Aviation Turbine Fuels from Tar Sands Bitumen and Heavy Oils. Part 2. Laboratory Sample Production.

DTIC Science & Technology

1987-07-01

tar sand bitumen from West Central Kentucky; and Sunnyside tar sand bitumen from the Uinta Basin , Utah. Each of the feedstocks had unique...fuel and about 50 volume percent heavy gas oil (600-1000°F). The Westken bitumen was overall the heaviest of the four feedstocks evaluated. K factors...was 40 weight percent and about 20 weight percent in the total crude. 3. San Ardo Heavy oil The San Ardo field is located in the Coastal basin of the

The extraction of bitumen from western oil sands. Final report, July 1989--September 1993

DOE Office of Scientific and Technical Information (OSTI.GOV)

Oblad, A.G.; Bunger, J.W.; Dahlstrom, D.A.

1994-03-01

Research and development of surface extraction and upgrading processes of western tar sands are described. Research areas included modified hot water, fluidized bed, and rotary kiln pyrolysis of tar sands for extraction of bitumen. Bitumen upgrading included solvent extraction of bitumen, and catalytic hydrotreating of bitumen. Characterization of Utah tar sand deposits is also included.

Heating tar sands formations while controlling pressure

DOEpatents

Stegemeier, George Leo [Houston, TX; Beer, Gary Lee [Houston, TX; Zhang, Etuan [Houston, TX

2010-01-12

Methods for treating a tar sands formation are described herein. Methods may include heating at least a section of a hydrocarbon layer in the formation from a plurality of heaters located in the formation. A pressure in the majority of the section may be maintained below a fracture pressure of the formation. The pressure in the majority of the section may be reduced to a selected pressure after the average temperature reaches a temperature that is above 240.degree. C. and is at or below pyrolysis temperatures of hydrocarbons in the section. At least some hydrocarbon fluids may be produced from the formation.

Laboratory studies to characterize the efficacy of sand capping a coal tar-contaminated sediment.

PubMed

Hyun, Seunghun; Jafvert, Chad T; Lee, Linda S; Rao, P Suresh C

2006-06-01

Placement of a microbial active sand cap on a coal tar-contaminated river sediment has been suggested as a cost effective remediation strategy. This approach assumes that the flux of contaminants from the sediment is sufficiently balanced by oxygen and nutrient fluxes into the sand layer such that microbial activity will reduce contaminant concentrations within the new benthic zone and reduce the contaminant flux to the water column. The dynamics of such a system were evaluated using batch and column studies with microbial communities from tar-contaminated sediment under different aeration and nutrient inputs. In a 30-d batch degradation study on aqueous extracts of coal tar sediment, oxygen and nutrient concentrations were found to be key parameters controlling the degradation rates of polycyclic aromatic hydrocarbons (PAHs). For the five PAHs monitored (naphthalene, fluorene, phenanthrene, anthracene, and pyrene), degradation rates were inversely proportional to molecular size. For the column studies, where three columns were packed with a 20-cm sand layer on the top of a 5 cm of sediment layer, flow was established to sand layers with (1) aerated water, (2) N(2) sparged water, or (3) HgCl(2)-sterilized N(2) sparged water. After steady-state conditions, PAH concentrations in effluents were the lowest in the aerated column, except for pyrene, whose concentration was invariant with all effluents. These laboratory scale studies support that if sufficient aeration can be achieved in the field through either active and passive means, the resulting microbially active sand layer can improve the water quality of the benthic zone and reduce the flux of many, but not all, PAHs to the water column.

An NMR (Nuclear Magnetic Resonance) Investigation of the Chemical Association and Molecular Dynamics in Asphalt Ridge Tar Sand Ore and Bitumen

DOE R&D Accomplishments Database

Netzel, D. A.; Coover, P. T.

1987-09-01

Preliminary studies on tar sand bitumen given in this report have shown that the reassociation of tar sand bitumen to its original molecular configuration after thermal stressing is a first-order process requiring nearly a week to establish equilibrium. Studies were also conducted on the dissolution of tar sand bitumen in solvents of varying polarity. At a high-weight fraction of solute to solvent the apparent molecular weight of the bitumen molecules was greater than that of the original bitumen when dissolved in chloroform-d{sub 1} and benzene-d{sub 6}. This increase in the apparent molecular weight may be due to micellar formation or a weak solute-solvent molecular complex. Upon further dilution with any of the solvents studied, the apparent molecular weight of the tar sand bitumen decreased because of reduced van der Waals forces of interaction and/or hydrogen bonding. To define the exact nature of the interactions, it will be necessary to have viscosity measurements of the solutions.

Natural radioactivity of the tar-sand deposits of Ondo State, Southwestern Nigeria

NASA Astrophysics Data System (ADS)

Fasasi, M. K.; Oyawale, A. A.; Mokobia, C. E.; Tchokossa, P.; Ajayi, T. R.; Balogun, F. A.

2003-06-01

A combination of gamma spectrometry and energy dispersive X-ray fluorescence was used to determine the presence and level of radioactivity of radionuclides in bituminous sand and overburden obtained from bituminous sand deposits in Ondo State Nigeria for the purpose of providing baseline data and assessing its impact on the environment. The radionuclides identified with reliable regularity belong to the decay series of naturally occurring radionuclides headed by 238U and 232Th. The non-decay series of naturally occurring 40K was found to be below the limit of detection. The average specific activity concentration values obtained for 214 Bi, 208Tl, and 226Ra in the overburden are 165.64±2.91, 150.25±2.91 and 60.97±2.27 Bq kg -1, respectively. The measured activity in the bituminous sand layer is so low that it can be said to be non-radioactive. The result of the EDXRF supports the presence of radioelements in the overburden, which are likely to be embedded in accessory minerals like zircon and tourmaline. Thus, surface exploration technique using soil-gas radon measurement will not yield the desired result. Furthermore, the level of radioelements and associated decay daughter 222Rn is not expected to cause any health hazard.

Production from multiple zones of a tar sands formation

DOEpatents

Karanikas, John Michael; Vinegar, Harold J

2013-02-26

A method for treating a tar sands formation includes providing heat to at least part of a hydrocarbon layer in the formation from a plurality of heaters located in the formation. The heat is allowed to transfer from the heaters to at least a portion of the formation. Fluids are produced from the formation through at least one production well that is located in at least two zones in the formation. The first zone has an initial permeability of at least 1 darcy. The second zone has an initial of at most 0.1 darcy. The two zones are separated by a substantially impermeable barrier.

Modeling surficial sand and gravel deposits

USGS Publications Warehouse

Bliss, J.D.; Page, N.J.

1994-01-01

Mineral-deposit models are an integral part of quantitative mineral-resource assessment. As the focus of mineral-deposit modeling has moved from metals to industrial minerals, procedure has been modified and may be sufficient to model surficial sand and gravel deposits. Sand and gravel models are needed to assess resource-supply analyses for planning future development and renewal of infrastructure. Successful modeling of sand and gravel deposits must address (1) deposit volumes and geometries, (2) sizes of fragments within the deposits, (3) physical characteristics of the material, and (4) chemical composition and chemical reactivity of the material. Several models of sand and gravel volumes and geometries have been prepared and suggest the following: Sand and gravel deposits in alluvial fans have a median volume of 35 million m3. Deposits in all other geologic settings have a median volume of 5.4 million m3, a median area of 120 ha, and a median thickness of 4 m. The area of a sand and gravel deposit can be predicted from volume using a regression model (log [area (ha)] =1.47+0.79 log [volume (million m3)]). In similar fashion, the volume of a sand and gravel deposit can be predicted from area using the regression (log [volume (million m3)]=-1.45+1.07 log [area (ha)]). Classifying deposits by fragment size can be done using models of the percentage of sand, gravel, and silt within deposits. A classification scheme based on fragment size is sufficiently general to be applied anywhere. ?? 1994 Oxford University Press.

Tar sand extraction by steam stimulation and steam drive: measurement of physical properties

DOE Office of Scientific and Technical Information (OSTI.GOV)

Linberg, W.R.

The measurement of the following thermophysical properties of Utah tar sands is in progress: thermal conductivity, specific heat relative permeability, and viscosity (of the recovered bitumen). During the report period (October 1, 1978 to November 1, 1979), experimental procedures have been developed and a basic data set has been measured. Additionally, standard core analysis has been performed for four drill sites in the Asphalt Ridge, Utah area.

Potential impacts to perennial springs from tar sand mining, processing, and disposal on the Tavaputs Plateau, Utah, USA.

PubMed

Johnson, William P; Frederick, Logan E; Millington, Mallory R; Vala, David; Reese, Barbara K; Freedman, Dina R; Stenten, Christina J; Trauscht, Jacob S; Tingey, Christopher E; Kip Solomon, D; Fernandez, Diego P; Bowen, Gabriel J

2015-11-01

Similar to fracking, the development of tar sand mining in the U.S. has moved faster than understanding of potential water quality impacts. Potential water quality impacts of tar sand mining, processing, and disposal to springs in canyons incised approximately 200 m into the Tavaputs Plateau, at the Uinta Basin southern rim, Utah, USA, were evaluated by hydrogeochemical sampling to determine potential sources of recharge, and chemical thermodynamic estimations to determine potential changes in transfer of bitumen compounds to water. Because the ridgetops in an area of the Tavaputs Plateau named PR Spring are starting to be developed for their tar sand resource, there is concern for potential hydrologic connection between these ridgetops and perennial springs in adjacent canyons on which depend ranching families, livestock, wildlife and recreationalists. Samples were collected from perennial springs to examine possible progression with elevation of parameters such as temperature, specific conductance, pH, dissolved oxygen, isotopic tracers of phase change, water-rock interaction, and age since recharge. The groundwater age dates indicate that the springs are recharged locally. The progression of hydrogeochemical parameters with elevation, in combination with the relatively short groundwater residence times, indicate that the recharge zone for these springs includes the surrounding ridges, and thereby suggests a hydrologic connection between the mining, processing, disposal area and the springs. Estimations based on chemical thermodynamic approaches indicate that bitumen compounds will have greatly enhanced solubility in water that comes into contact with the residual bitumen-solvent mixture in disposed tailings relative to water that currently comes into contact with natural tar. Copyright © 2015 Elsevier B.V. All rights reserved.

Systems and methods for producing hydrocarbons from tar sands formations

DOEpatents

Li, Ruijian [Katy, TX; Karanikas, John Michael [Houston, TX

2009-07-21

A system for treating a tar sands formation is disclosed. A plurality of heaters are located in the formation. The heaters include at least partially horizontal heating sections at least partially in a hydrocarbon layer of the formation. The heating sections are at least partially arranged in a pattern in the hydrocarbon layer. The heaters are configured to provide heat to the hydrocarbon layer. The provided heat creates a plurality of drainage paths for mobilized fluids. At least two of the drainage paths converge. A production well is located to collect and produce mobilized fluids from at least one of the converged drainage paths in the hydrocarbon layer.

In situ heat treatment from multiple layers of a tar sands formation

DOEpatents

Vinegar, Harold J.

2010-11-30

A method for treating a tar sands formation is disclosed. The method includes providing a drive fluid to a first hydrocarbon containing layer of the formation to mobilize at least some hydrocarbons in the first layer. At least some of the mobilized hydrocarbons are allowed to flow into a second hydrocarbon containing layer of the formation. Heat is provided to the second layer from one or more heaters located in the second layer. At least some hydrocarbons are produced from the second layer of the formation.

Method of condensing vaporized water in situ to treat tar sands formations

DOEpatents

Hsu, Chia-Fu

2010-03-16

Methods for treating a tar sands formation are described herein. Methods may include heating at least a section of a hydrocarbon layer in the formation from a plurality of heaters located in the formation. Heat may be allowed to transfer from the heaters to at least a first portion of the formation. Conditions may be controlled in the formation so that water vaporized by the heaters in the first portion is selectively condensed in a second portion of the formation. At least some of the fluids may be produced from the formation.

Moving hydrocarbons through portions of tar sands formations with a fluid

DOEpatents

Stegemeier, George Leo; Mudunuri, Ramesh Raju; Vinegar, Harold J.; Karanikas, John Michael; Jaiswal, Namit; Mo, Weijian

2010-05-18

A method for treating a tar sands formation is disclosed. The method includes heating a first portion of a hydrocarbon layer in the formation from one or more heaters located in the first portion. The heat is controlled to increase a fluid injectivity of the first portion. A drive fluid and/or an oxidizing fluid is injected and/or created in the first portion to cause at least some hydrocarbons to move from a second portion of the hydrocarbon layer to a third portion of the hydrocarbon layer. The second portion is between the first portion and the third portion. The first, second, and third portions are horizontally displaced from each other. The third portion is heated from one or more heaters located in the third portion. Hydrocarbons are produced from the third portion of the formation. The hydrocarbons include at least some hydrocarbons from the second portion of the formation.

Effects of varying marijuana potency on deposition of tar and delta9-THC in the lung during smoking.

PubMed

Matthias, P; Tashkin, D P; Marques-Magallanes, J A; Wilkins, J N; Simmons, M S

1997-12-01

To determine whether smoking more, compared to less, potent marijuana (MJ) cigarettes to a desired level of intoxication ("high") reduces pulmonary exposure to noxious smoke components, in 10 habitual smokers of MJ, we measured respiratory delivery and deposition of tar and delta9-tetrahydrocannabinol (THC), carboxyhemoglobin (COHb) boost, smoking topography, including cumulative puff volume (CPV) and breathholding time, change in heart rate (deltaHR) and "high" during ad lib smoking of 0, 1.77, and 3.95% MJ cigarettes on 3 separate days. At each session, subjects had access to only a single MJ cigarette. On average, smoking topography and COHb boost did not differ across the different strengths of MJ, while THC delivery, as well as HR, were significantly greater (p < 0.01) and tar deposition significantly less (p < 0.03) for 3.95% than 1.77% MJ. Although individual adaptations in smoking topography for 3.95% compared to 1.77% MJ were highly variable, three subjects with the lowest 3.95% MJ:1.77% MJ ratios for CPV also displayed the lowest 3.95% MJ:1.77% MJ ratios for tar deposition. In vitro studies using a standardized smoking technique revealed a mean 25% lower tar yield from 3.95% than 1.77% MJ (p < 0.05), but no difference between 1.77% and 0% marijuana. Under the conditions of this study, we conclude that tar delivery is reduced relative to THC content in a minority of subjects, and this reduction appears to be due to a reduced intake of smoke (decreased CPV) and/or a reduced tar yield from the stronger MJ preparation.

Depositional settings of sand beaches along whitewater rivers

USGS Publications Warehouse

Vincent, K.R.; Andrews, E.D.

2008-01-01

The numbers and sizes of sand beaches suitable for recreation along selected whitewater rivers in the western United States depend on sand concentrations, range of discharge and the size, frequency and type of depositional settings. River-width expansions downstream from constrictions are the predominant depositional setting for sand beaches in the upper Grand Canyon and along five Wild and Scenic Rivers in Idaho, but not along other rivers. Beaches located upstream from constrictions are rare, in general, except in the Grand Canyon. Beaches found in expansions without constrictions dominate depositional sites along the Yampa and Green Rivers, are fairly common along the rivers in Idaho, but are relatively rare in the Grand Canyon. The magnitude of flow expansion is a reliable predictor of beach size. Beaches located on the inside of curves are uncommon, in general, but can be important recreation sites. The mid-channel bar setting is the least important from a recreation standpoint because that setting is rare and beaches there are typically small, and emergent only at low flow. The frequency of beaches is highly variable among rivers and the concentration of sand in transport is only partially responsible. Of the rivers studied, the unregulated Yampa River carries the highest concentrations of suspended sand and has among the most beaches (1.2 beaches km-1). Emergent sand beaches are essentially nonexistent along the Deschutes River and are rare along other Oregon rivers, yet these rivers transport some sand. Sand beaches are fairly common (0.8-1.1 beaches km-1) along the regulated Colorado River, but are comparatively rare (0.6 beaches km-1) along the unregulated Middle Fork Salmon River. The suspended sand concentrations in study reaches of these two rivers are similar, and the difference in the frequency of beaches may be largely because the processes that create beach-deposition settings are less active along the Middle Fork Salmon.

Identification of sources of tar balls deposited along the Goa coast, India, using fingerprinting techniques.

PubMed

Suneel, V; Vethamony, P; Zakaria, M P; Naik, B G; Prasad, K V S R

2013-05-15

Deposition of tar balls along the coast of Goa, India is a common phenomenon during the southwest monsoon. Representative tar ball samples collected from various beaches of Goa and one Bombay High (BH) crude oil sample were subjected to fingerprint analysis based on diagnostic ratios of n-alkane, biomarkers of pentacyclic tri-terpanes and compound specific stable carbon isotope (δ¹³C) analysis to confirm the source. The results were compared with the published data of Middle East Crude Oil (MECO) and South East Asian Crude Oil (SEACO). The results revealed that the tar balls were from tanker-wash derived spills. The study also confirmed that the source is not the BH, but SEACO. The present study suggests that the biomarkers of alkanes and hopanes coupled with stable carbon isotope analysis act as a powerful tool for tracing the source of tar balls, particularly when the source specific biomarkers fail to distinguish the source. Copyright © 2013 Elsevier Ltd. All rights reserved.

Sand deposition in shoreline eddies along five Wild and Scenic Rivers, Idaho

USGS Publications Warehouse

Andrews, E.D.; Vincent, K.R.

2007-01-01

Sand bars deposited along the lateral margin of a river channel are frequently a focus of recreational activities. Sand bars are appealing sites on which to camp, picnic, fish and relax because they are relatively flat, soft, non-cohesive sand, free of vegetation and near the water's edge. The lack of vegetation and cohesion make sand bars easily erodible. Without appreciable deposition of new material, number and size of bars through a given reach of river will decline substantially over a period of years. We studied 63 beaches and their associated eddies located throughout 10 selected reaches within the designated Wild and Scenic River sections of the Lochsa, Selway, Middle Fork Clearwater, Middle Fork Salmon and Salmon Rivers in Idaho to determine the relation of beaches to the frequency and magnitude of streamflows that deposit appreciable quantities of sand. At present, these rivers have been altered little, if at all, by flow regulation, and only the Salmon River has substantial diversion upstream of a study reach. The river reaches studied have an abundance of sand bar beaches of appreciable size, in spite of suspended sand concentrations that rarely exceeded a few hundred milligrams per litre even during the largest floods. Calculated mean annual rates of deposition in an eddy vary from 5.8 to more than 100 cm depending primarily on: (1) the duration of streamflows that inundate the eddy sand bar depositions; (2) the rate of the flow exchange between the channel and an eddy and (3) the concentrations of suspended sand in the primary channel. The annual thickness of sand deposition in an eddy varies greatly from year to year depending on the duration of relatively large streamflows. Maximum annual sand depositions in an eddy are three to nine times the estimated long-term mean values. Relatively large, sustained floods deposit an appreciable portion of total deposition over a period of years. For the period of record, 1930-2002, the seven largest annual

The extraction of bitumen from western oil sands. Annual report, July 1991--July 1992

DOE Office of Scientific and Technical Information (OSTI.GOV)

Oblad, A.G.; Bunger, J.W.; Dahlstrom, D.A.

1992-08-01

The University of Utah tar sand research and development program is concerned with research and development on Utah is extensive oil sands deposits. The program has been intended to develop a scientific and technological base required for eventual commercial recovery of the heavy oils from oil sands and processing these oils to produce synthetic crude oil and other products such as asphalt. The overall program is based on mining the oil sand, processing the mined sand to recover the heavy oils and upgrading them to products. Multiple deposits are being investigated since it is believed that a large scale (approximatelymore » 20,000 bbl/day) plant would require the use of resources from more than one deposit. The tasks or projects in the program are organized according to the following classification: Recovery technologies which includes thermal recovery methods, water extraction methods, and solvent extraction methods; upgrading and processing technologies which covers hydrotreating, hydrocracking, and hydropyrolysis; solvent extraction; production of specialty products; and environmental aspects of the production and processing technologies. These tasks are covered in this report.« less

Modeling the impact of bubbling bed hydrodynamics on tar yield and its fluctuations during biomass fast pyrolysis

DOE PAGES

Xiong, Qingang; Ramirez, Emilio; Pannala, Sreekanth; ...

2015-10-09

The impact of bubbling bed hydrodynamics on temporal variations in the exit tar yield for biomass fast pyrolysis was investigated using computational simulations of an experimental laboratory-scale reactor. A multi-fluid computational fluid dynamics model was employed to simulate the differential conservation equations in the reactor, and this was combined with a multi-component, multi-step pyrolysis kinetics scheme for biomass to account for chemical reactions. The predicted mean tar yields at the reactor exit appear to match corresponding experimental observations. Parametric studies predicted that increasing the fluidization velocity should improve the mean tar yield but increase its temporal variations. Increases in themore » mean tar yield coincide with reducing the diameter of sand particles or increasing the initial sand bed height. However, trends in tar yield variability are more complex than the trends in mean yield. The standard deviation in tar yield reaches a maximum with changes in sand particle size. As a result, the standard deviation in tar yield increases with the increases in initial bed height in freely bubbling state, while reaches a maximum in slugging state.« less

Erosion and Deposition in Schaeberle Crater

NASA Image and Video Library

2016-01-14

Schaeberle Crater is a large, heavily-infilled crater with many interesting features. This image NASA Mars Reconnaissance Orbiter spacecraft shows a window into the crater fill deposit, showcasing eroding bedrock and aeolian landforms. This pit is located near the geometric center of our image, making it a central pit crater. Central pit craters are thought to form from impact melt draining through subsurface cracks in the deepest part of the crater shortly following impact. A closeup image shows light-toned bedrock and a small cliff that appears to be weathering away. Below the cliff there are several different types of aeolian features, including ripples and transverse aeolian ridges (TAR). The sand that forms the small, bluish ripples may be weathering out of the cliff face, in contrast to the larger, light-toned TAR which are thought to be currently inactive. More of the TAR are visible in another closeup image. In this case, they are clearly covered by a dark, ripple-covered sand sheet. We have only imaged this location once, so it is impossible to determine whether or not the sand sheet is blowing in the wind. But due to repeated HiRISE imaging in other areas, active dunes are now known to be common across Mars and we can reasonably speculate that these dunes are moving, too. http://photojournal.jpl.nasa.gov/catalog/PIA20339

Hydrogeology of sand and gravel deposits near Nepaug Reservoir, New Hartford and Burlington, Connecticut

USGS Publications Warehouse

Stone, Janet Radway; Starn, J. Jeffrey; Morrison, Jonathan

2001-01-01

Sand and gravel deposits near the Nepaug Reservoir in New Hartford and Burlington, Connecticut, were studied to provide a basis for ongoing investigations that will evaluate water-quality conditions in the watershed and the effects of sand and gravel mining on the quality of water in the reservoir. In the Nepaug area, surficial glacial materials overlie crystalline bedrock that is predominantly schist and gneiss. Along the western side of Nepaug Reservoir, glacial stratified deposits were laid down as ice-marginal deltas in a series of small glacial lakes that formed sequentially as the ice margin retreated northeastward through the area. These deposits are as much as 250 feet thick and are subdivided into coarse-grained units (gravel, sand and gravel, and sand deposits) and fine-grained units (very fine sand, silt, and clay deposits). Approximately 954 million cubic feet of sand and gravel is contained in four delineated deposits in two areas near the reservoir. The sand and gravel deposits adjacent to the Nepaug Reservoir can affect the physical and chemical responses of the watershed. Removal of the sand and gravel would likely result in increased streamflow peaks associated with storms and decreased streamflow during low-flow periods. Streamflow during floods and droughts at Burlington Brook and Clear Brook, a tributary to the Nepaug Reservoir, were compared to determine how the volume of sand and gravel in a watershed affects ground-water storage and the way water is released from storage. Removal of unsaturated deposits also may affect chemical interactions between water and sediment and cause changes in the amount of dissolved constituents in the water.

Varying properties of in situ heat treatment of a tar sands formation based on assessed viscosities

DOEpatents

Karanikas, John Michael; Vinegar, Harold J

2014-03-04

A method for treating a tar sands formation includes providing heat to at least part of a hydrocarbon layer in the formation from a plurality of heaters located in the formation. The heat is allowed to transfer from the heaters to at least a portion of the formation. A viscosity of one or more zones of the hydrocarbon layer is assessed. The heating rates in the zones are varied based on the assessed viscosities. The heating rate in a first zone of the formation is greater than the heating rate in a second zone of the formation if the viscosity in the first zone is greater than the viscosity in the second zone. Fluids are produced from the formation through the production wells.

Geomorphology and drift potential of major aeolian sand deposits in Egypt

NASA Astrophysics Data System (ADS)

Hereher, Mohamed E.

2018-03-01

Aeolian sand deposits cover a significant area of the Egyptian deserts. They are mostly found in the Western Desert and Northern Sinai. In order to understand the distribution, pattern and forms of sand dunes in these dune fields it is crucial to analyze the wind regimes throughout the sandy deserts of the country. Therefore, a set of wind data acquired from twelve meteorological stations were processed in order to determine the drift potential (DP), the resultant drift potential (RDP) and the resultant drift direction (RDD) of sand in each dune field. The study showed that the significant aeolian sand deposits occur in low-energy wind environments with the dominance of linear and transverse dunes. Regions of high-energy wind environments occur in the south of the country and exhibit evidence of deflation rather than accumulation with the occurrence of migratory crescentic dunes. Analysis of the sand drift potentials and their directions help us to interpret the formation of major sand seas in Egypt. The pattern of sand drift potential/direction suggests that the sands in these seas might be inherited from exogenous sources.

Silica removal from steamflood-produced water: South Texas tar sands pilot

DOE Office of Scientific and Technical Information (OSTI.GOV)

Thomas, S.A.; Yost, M.E.; Cathey, S.R.

1987-05-01

Steamflood-produced waters commonly contain suspended solids, oil, hardness-causing minerals, sulfide, and silica. Removal of these contaminants would make many of these waters suitable for recycling as steamer feedwater. Reuse of steamflood-produced waters increases steamer feedwater supplies and reduces water disposal requirements. This paper describes a field pilot study of silica removal from steamflood-produced water in the south Texas tar sands region. A hot-lime precipitation process was used to reduce dissolved silica (SiO/sub 2/) concentrations from 400 to less than 50 mg/L SiO/sub 2/ in Mary R. Saner Ranch produced water. Most water systems using hot-lime precipitation for silica removal requiremore » the addition of magnesium salt, as well as lime, to enhance silica removal. In this field study, however, addition of magnesium salt did not improve silica removal efficiency. Hydrated lime, CA(OH)/sub 2/, alone was sufficient to attain desired silica residual, 50 mg/L SiO/sub 2/. The dissolved silica adsorbed onto the CaCO/sub 3/ crystals formed by lime reacting with the alkalinity present in the produced water. Required lime dosage was approximately 900 mg/L Ca(OH)/sub 2/.« less

Hydraulic experiment on tsunami sand deposits relating with grain size distribution and magnitude of incident waves

NASA Astrophysics Data System (ADS)

Yamamoto, A.; Takahashi, T.; Harada, K.; Nojima, K.

2016-12-01

A huge earthquake occurred off the Tohoku district in Japan on March 11th, 2011. A massive tsunami generated by the earthquake attacked coastal areas and caused serious damage. The tsunami disaster requires to reconsider tsunami measures in the Nankai Trough. Many of the measures are based on histories of large earthquakes and tsunamis. Because they are low frequency disasters and their historical documents are limited, tsunami sand deposits have been expected to analyze paleotsunamis. Tsunami sand deposits, however, are only used to confirm the fact of tsunamis and to determine the relative magnitudes. The thickness of sand layer and the grain size may be clues to estimate the tsunami force. Further, it could reveal the tsunami source. These results are also useful to improve the present tsunami measures. The objective of this study is to investigate the formation mechanism of tsunami sand deposits by hydraulic experiment. A two-dimensional water channel consisted of a wave maker, a flat section and a slope section. A movable bed section with various grain sizes and distribution of sand was set at the end of flat section. Bore waves of several heights transported the sand to the slope section by run-up. Water surface elevation and velocity were measured at several points. Tsunami sand deposit distribution was also measured along the slope section. The experimental result showed that the amount of tsunami sand deposit was relating with the grain size distribution and the magnitude of incident waves. Further, the number of incident waves affected the profile of tsunami sand deposits.

Modeling Cape- and Ridge-Associated Marine Sand Deposits; A Focus on the U.S. Atlantic Continental Shelf

USGS Publications Warehouse

Bliss, James D.; Williams, S. Jeffress; Bolm, Karen S.

2009-01-01

Cape- and ridge-associated marine sand deposits, which accumulate on storm-dominated continental shelves that are undergoing Holocene marine transgression, are particularly notable in a segment of the U.S. Atlantic Continental Shelf that extends southward from the east tip of Long Island, N.Y., and eastward from Cape May at the south end of the New Jersey shoreline. These sand deposits commonly contain sand suitable for shore protection in the form of beach nourishment. Increasing demand for marine sand raises questions about both short- and long-term potential supply and the sustainability of beach nourishment with the prospects of accelerating sea-level rise and increasing storm activity. To address these important issues, quantitative assessments of the volume of marine sand resources are needed. Currently, the U.S. Geological Survey is undertaking these assessments through its national Marine Aggregates and Resources Program (URL http://woodshole.er.usgs.gov/project-pages/aggregates/). In this chapter, we present a hypothetical example of a quantitative assessment of cape-and ridge-associated marine sand deposits in the study area, using proven tools of mineral-resource assessment. Applying these tools requires new models that summarize essential data on the quantity and quality of these deposits. Two representative types of model are descriptive models, which consist of a narrative that allows for a consistent recognition of cape-and ridge-associated marine sand deposits, and quantitative models, which consist of empirical statistical distributions that describe significant deposit characteristics, such as volume and grain-size distribution. Variables of the marine sand deposits considered for quantitative modeling in this study include area, thickness, mean grain size, grain sorting, volume, proportion of sand-dominated facies, and spatial density, of which spatial density is particularly helpful in estimating the number of undiscovered deposits within an

Study on tar generated from downdraft gasification of oil palm fronds.

PubMed

Atnaw, Samson Mekbib; Kueh, Soo Chuan; Sulaiman, Shaharin Anwar

2014-01-01

One of the most challenging issues concerning the gasification of oil palm fronds (OPF) is the presence of tar and particulates formed during the process considering its high volatile matter content. In this study, a tar sampling train custom built based on standard tar sampling protocols was used to quantify the gravimetric concentration of tar (g/Nm3) in syngas produced from downdraft gasification of OPF. The amount of char, ash, and solid tar produced from the gasification process was measured in order to account for the mass and carbon conversion efficiency. Elemental analysis of the char and solid tar samples was done using ultimate analysis machine, while the relative concentration of the different compounds in the liquid tar was determined making use of a liquid gas chromatography (GC) unit. Average tar concentration of 4.928 g/Nm3 and 1.923 g/Nm3 was obtained for raw gas and cleaned gas samples, respectively. Tar concentration in the raw gas sample was found to be higher compared to results for other biomass materials, which could be attributed to the higher volatile matter percentage of OPF. Average cleaning efficiency of 61% which is comparable to that of sand bed filter and venturi scrubber cleaning systems reported in the literature was obtained for the cleaning system proposed in the current study.

Study on Tar Generated from Downdraft Gasification of Oil Palm Fronds

PubMed Central

Atnaw, Samson Mekbib; Kueh, Soo Chuan; Sulaiman, Shaharin Anwar

2014-01-01

One of the most challenging issues concerning the gasification of oil palm fronds (OPF) is the presence of tar and particulates formed during the process considering its high volatile matter content. In this study, a tar sampling train custom built based on standard tar sampling protocols was used to quantify the gravimetric concentration of tar (g/Nm3) in syngas produced from downdraft gasification of OPF. The amount of char, ash, and solid tar produced from the gasification process was measured in order to account for the mass and carbon conversion efficiency. Elemental analysis of the char and solid tar samples was done using ultimate analysis machine, while the relative concentration of the different compounds in the liquid tar was determined making use of a liquid gas chromatography (GC) unit. Average tar concentration of 4.928 g/Nm3 and 1.923 g/Nm3 was obtained for raw gas and cleaned gas samples, respectively. Tar concentration in the raw gas sample was found to be higher compared to results for other biomass materials, which could be attributed to the higher volatile matter percentage of OPF. Average cleaning efficiency of 61% which is comparable to that of sand bed filter and venturi scrubber cleaning systems reported in the literature was obtained for the cleaning system proposed in the current study. PMID:24526899

Silica removal from steamflood produced water: South Texas Tar Sands Pilot

DOE Office of Scientific and Technical Information (OSTI.GOV)

Thomas, S.A.; Cathey, S.R.; Yost, M.E.

1984-09-01

Steamflood produced waters commonly contain suspended solids, oil, hardness, sulfide, and silica. Removal of these contaminants would make many of these waters suitable candidates for recycling as steam feedwater. Reuse of steamflood produced waters will increase steamer feedwater supplies, as well as reduce water disposal requirements. This paper describes a field pilot study of silica removal from steamflood produced water in the South Texas Tar Sands region. A hot-lime precipitation process was used to reduce dissolved silica concentrations from 400 mg/l to less than 50 mg/l SiO/sub 2/ in Mary R. Saner Ranch produced water. Most water systems using hot-limemore » precipitation for silica removal call for the addition of magnesium salts, as well as lime, to enhance silica removal. In this field study, however, magnesium salt addition did not improve silica removal efficiency. Hydrated lime ((Ca(OH)/sub 2/), alone, was sufficient to attain the desired silica residual, 50 mg/l SiO/sub 2/. The dissolved silica adsorbed onto the CaCO/sub 3/ crystals formed by lime reacting with the alkalinity present in the produced water. Required lime dosage was approximately 900 mg/lCa(OH)/sub 2/. Residual silica concentrations were found to be strongly related to both precipitator pH and calcium ion concentration. Therefore, on-line pH and hardness monitoring may be used to estimate and control residual silica concentration. A 50,000-BPD (7,900 m/sup 3//d) produced water treating plant has been designed using results from this pilot study.« less

Aggradation and degradation of alluvial sand deposits, 1965 to 1986, Colorado River, Grand Canyon National Park, Arizona

USGS Publications Warehouse

Schmidt, John C.; Graf, Julia B.

1990-01-01

Alluvial sand deposits along the Colorado River in Grand Canyon National Park are used as campsites and are substrate for vegetation. The largest and most numerous of these deposits are formed in zones of recirculating current that are created downstream from where the channel is constricted by debris fans at tributary mouths. Alluvial sand deposits are classified by location and form. Separation and reattachment deposits are downstream from constrictions within recirculation zones. Separation deposits are near the point of flow separation and typically mantle large debris fans. Reattachment deposits are near the point of flow reattachment and project upstream beneath much of the zone of recirculating current. Upper-pool deposits are upstream from a constriction and are associated with backwaters. Channel-margin deposits line the channel and have the form of terraces. Some are created in small recirculation zones. Reattachment and channel-margin deposits are largest and most numerous in wide reaches, although small channel-margin deposits are used as campsites in the narrow Muav Gorge. Separation deposits are more uniformly distributed throughout Grand Canyon National Park than are other types of deposits. In some narrow reaches where the number of alluvial sand deposits used as campsites is small, separation deposits are a high percentage of the total. During high flows, both separation and reattachment deposits are initially scoured but are subsequently redeposited during flow recession. Sand is also exchanged between the main channel and recirculation zones. The rate of recession of high flows can affect the elevation of alluvial deposits that are left exposed after a flood has passed. Fluctuating flows that follow a period of steady discharge cause initial erosion of separation and reattachment deposits. A part of this eroded sand is transported to the main channel. Therefore, sand is exchanged between the main channel and recirculation zones and redistributed

Sand deposition in the Colorado River in the Grand Canyon from flooding of the Little Colorado River

USGS Publications Warehouse

Wiele, S.M.; Graf, J.B.; Smith, J.D.

1996-01-01

Methods for computing the volume of sand deposited in the Colorado River in Grand Canyon National Park by floods in major tributaries and for determining redistribution of that sand by main-channel flows are required for successful management of sand-dependent riparian resources. We have derived flow, sediment transport, and bed evolution models based on a gridded topography developed from measured channel topography and used these models to compute deposition in a short reach of the river just downstream from the Little Colorado River, the largest tributary in the park. Model computations of deposition from a Little Colorado River flood in January 1993 were compared to bed changes measured at 15 cross sections. The total difference between changes in cross-sectional area due to deposition computed by the model and the measured changes was 6%. A wide reach with large areas of recirculating flow and large depressions in the main channel accumulated the most sand, whereas a reach with similar planimetric area but a long, narrow shape and relatively small areas of recirculating flow and small depressions in the main channel accumulated only about a seventh as much sand. About 32% of the total deposition was in recirculation zones, 65% was in the main channel, and 3% was deposited along the channel margin away from the recirculation zone. Overall, about 15% of the total input of sand from this Little Colorado River flood was deposited in the first 3 km below the confluence, suggesting that deposition of the flood-derived material extended for only several tens of kilometers downstream from the confluence.

Identifying the source of tar balls deposited along the beaches of Goa in 2013 and comparing with historical data collected along the West Coast of India.

PubMed

Suneel, V; Vethamony, P; Naik, B G; Krishna, M S; Jadhav, Lakshmikant

2015-09-15

Deposition of oil residues, also known as tar balls, is a seasonal phenomenon, and it occurs only in the southwest monsoon season along the west coast of India. This has become a serious environmental issue, as Goa is a global tourist destination. The present work aims at identifying the source oil of the tar balls that consistently depositing along the Goa coast using multi-marker fingerprint technique. In this context, the tar ball samples collected in May 2013 from 9 beaches of Goa coast and crude oils from different oil fields and grounded ship were subject to multi-marker analyses such as n-alkanes, pentacyclic terpanes, regular steranes, compound specific isotope analysis (CSIA) and principle component analysis (PCA). The n-alkane weathering index shows that samples have been weathered to various degrees, and the status of weathering is moderate. Since the international tanker route passes closer to the west coast of India (WCI), it is generally presumed that tanker wash is the source of the tar balls. We found that 2010/2011 tar balls are as tanker wash, but the present study demonstrates that the Bombay High (BH) oil fields can also contribute to oil contamination (tar balls) along ≈ 650 km stretch of the WCI, running from Gujarat in the north to Goa in the south. The simulated trajectories show that all the particles released in April traveled in the southeast direction, and by May, they reached the Goa coast with the influence of circulation of Indian monsoon system. Copyright © 2015 Elsevier B.V. All rights reserved.

Coal Tar and Coal-Tar Pitch

Cancer.gov

Learn about coal-tar products, which can raise your risk of skin cancer, lung cancer, and other types of cancer. Examples of coal-tar products include creosote, coal-tar pitch, and certain preparations used to treat skin conditions such as eczema, psoriasis, and dandruff.

Modeling of flood-deposited sand distributions in a reach of the Colorado River below the Little Colorado River, Grand Canyon, Arizona

USGS Publications Warehouse

Wiele, S.M.

1998-01-01

A release from Glen Canyon Dam during March-April 1996 was designed to test the effectiveness with which the riparian environment could be renewed with discharges greatly in excess of the normal powerplant-restricted maximum. Of primary concern was the rebuilding of sand deposits along the channel sides that are important to the flora and fauna along the river corridor and that provide the only camp sites for riverside visitors to the Grand Canyon National Park. Analysis of the depositional processes with a model of flow, sand transport, and bed evolution shows that the sand deposits formed along the channel sides early during the high flow were affected only slightly by the decline in suspended-sand concentrations over the course of the controlled flood. Modeling results suggest that the removal of a large sand deposit over several hours was not a response to declining suspended-sand concentrations. Comparisons of the controlled-flood deposits with deposits formed during a flood in January 1993 on the Little Colorado River that contributed sufficient sand to raise the suspended-sand concentrations to predam levels in the main stem show that the depositional pattern as well as the magnitude is strongly influenced by the suspended-sand concentrations.

The chemistry of Saudi Arabian sand: A deposition problem on helicopter turbine airfoils

NASA Technical Reports Server (NTRS)

Smialek, James L.

1991-01-01

Recent operations in the Persian Gulf have exposed military helicopter turbines to excessive amounts of ingested sand. Fine particles, less than 10 microns, are able to bypass the particle separators and enter the cooling and combustion systems. The initial sand chemistry varies by location, but is made up of a calcium aluminum silicate glass, SiO2 low quartz (Ca,Mg) CO3 dolomite, CaCO3 calcite, and occasionally CaCl rocksalt. The sand reacts in the hot combustion gases and deposits onto the turbine vanes as CaSO4, glass, and various crystalline silicates. Deposits up to 0.25 in. thick have been collected. Although cooling hole plugging is a considerable problem, excessive corrosion is not commonly observed due to the high melting point of GaSO4.

The chemistry of Saudi Arabian sand - A deposition problem on helicopter turbine airfoils

NASA Astrophysics Data System (ADS)

Smialek, James L.; Archer, Frances A.; Garlick, Ralph G.

Operations in the Persian Gulf have exposed military helicopter turbines to excessive amounts of ingested sand. Fine particles, less than 10 microns, are able to bypass the particle separators and enter the cooling and combustion systems. The initial sand chemistry varies by location, but is made up of a calcium aluminum silicate glass, SiO2 low quartz, (Ca,Mg)CO3 dolomite, CaCO3 calcite, and occasionally NaCl rocksalt. The sand reacts in the hot combustion gases and deposits onto the turbine vanes as CaSO4, glass, and various crystalline silicates. Deposits up to 5 mm thick have been collected. Although cooling hole plugging is a considerable problem, excessive corrosion is not commonly observed due to the high melting point of CaSO4.

The Chemistry of Saudi Arabian Sand - A Deposition Problem on Helicopter Turbine Airfoils

NASA Technical Reports Server (NTRS)

Smialek, James L.; Archer, Frances A.; Garlick, Ralph G.

1992-01-01

Operations in the Persian Gulf have exposed military helicopter turbines to excessive amounts of ingested sand. Fine particles, less than 10 microns, are able to bypass the particle separators and enter the cooling and combustion systems. The initial sand chemistry varies by location, but is made up of a calcium aluminum silicate glass, SiO2 low quartz, (Ca,Mg)CO3 dolomite, CaCO3 calcite, and occasionally NaCl rocksalt. The sand reacts in the hot combustion gases and deposits onto the turbine vanes as CaSO4, glass, and various crystalline silicates. Deposits up to 5 mm thick have been collected. Although cooling hole plugging is a considerable problem, excessive corrosion is not commonly observed due to the high melting point of CaSO4.

Mineral Resource Assessment of Marine Sand Resources in Cape- and Ridge-Associated Marine Sand Deposits in Three Tracts, New York and New Jersey, United States Atlantic Continental Shelf

USGS Publications Warehouse

Bliss, James D.; Williams, S. Jeffress; Arsenault, Matthew A.

2009-01-01

Demand is growing in the United States and worldwide for information about the geology of offshore continental shelf regions, the character of the seafloor, and sediments comprising the seafloor and subbottom. Interest in locating sand bodies or high quality deposits that have potential as sources for beach nourishment and ecosystem restoration is especially great in some regions of the country. The Atlantic coast, particularly New York and New Jersey, has been the focus of these studies for the past 40 years with widely varying results. This study is the first attempt at applying probability statistics to modeling Holocene-age cape-and ridge-associated sand deposits and thus focuses on distinct sand body morphology. This modeling technique may have application for other continental shelf regions that have similar geologic character and late Quaternary sea-level transgression history. An estimated volume of 3.9 billion m3 of marine sand resources is predicted in the cape-and ridge-associated marine sand deposits in three representative regions or tracts on the continental shelf offshore of New York and New Jersey. These estimates are taken from probabilistic distributions of sand resources and are produced using deposit models and Monte Carlo Simulation (MCS) techniques. The estimated sand resources presented here are for only three tracts as described below and for Holocene age sand resources contained in cape-and ridge-associated marine sand deposit types within this area. Other areas may qualify as tracts for this deposit type and other deposit types and geologic ages (for example, paleo-stream channels, blanket and outwash deposits, ebb-tide shoals, and lower sea level-stand deltas), which are present on the New Jersey and New York continental shelf area but are not delineated and modeled in this initial evaluation. Admittedly, only a portion of these probable sand resources will ultimately be available and suitable for production, dependent largely on

Depositional analysis of Hill sand of Rodessa Formation (lower Cretaceous) in north Shongaloo-Red Rock field, Webster Parish, Louisiana

DOE Office of Scientific and Technical Information (OSTI.GOV)

Adamick, J.A.; Sartin, A.A.

1988-09-01

Hill sand is an informal subdivision of the Lower Cretaceous Rodessa Formation and is a common hydrocarbon reservoir in northeastern Texas, northern Louisiana, and southern Arkansas. The Hill sand is lithologically variable within the study area and consists of conglomerate, fine-grained sandstone, siltstone, mottled red-green claystone, black shale, and limestone. Five depositional environments were interpreted for lithofacies present in Hill sand cores from the North Shongaloo-Red Rock field. These include facies A, fluvial point bar; facies B, crevasse system; facies C, interdistributary bay; facies D, swamp; and facies E, carbonate interdistributary bay. Fluvial point bar and crevasse deposits commonly formmore » hydrocarbon reservoirs in the field. On a regional scale, depositional environments observed in the Hill sand include several fluvial deposystems trending northeast-southwest through Webster Parish. These deposystems terminate into deltaic distributary mouth bars along a northwest-southeast-trending coastline. Areas west of the coastline were occupied by shallow marine environments. Interchannel areas east of the coastline were occupied by interdistributary bay, lake, and crevasse environments in lower deltaic areas, and by lake, swamp, and crevasse environments in upper deltaic areas. Lowermost deposits of the Hill sand throughout the region are interpreted to consist of shallow marine environments. These marine deposits were overlain by thick, predominantly nonmarine sediments. Near the end of Hill sand deposition, the entire region was covered by very shallow marine environments, prior to deposition of the overlying First Lower Anhydrite Stringer.« less

Aeolian sand transport and aeolian deposits on Venus: A review

NASA Astrophysics Data System (ADS)

Kreslavsly, Mikhail A.; Bondarenko, Nataliya V.

2017-06-01

We review the current state of knowledge about aeolian sand transport and aeolian bedforms on planet Venus. This knowledge is limited by lack of observational data. Among the four planetary bodies of the Solar System with sufficient atmospheres in contact with solid surfaces, Venus has the densest atmosphere; the conditions there are transitional between those for terrestrial subaerial and subaqueous transport. The dense atmosphere causes low saltation threshold and short characteristic saltation length, and short scale length of the incipient dunes. A few lines of evidence indicate that the typical wind speeds exceed the saltation threshold; therefore, sand transport would be pervasive, if sand capable of saltation is available. Sand production on Venus is probably much slower than on the Earth; the major terrestrial sand sinks are also absent, however, lithification of sand through sintering is expected to be effective under Venus' conditions. Active transport is not detectable with the data available. Aeolian bedforms (transverse dunes) resolved in the currently available radar images occupy a tiny area on the planet; however, indirect observations suggest that small-scale unresolved aeolian bedforms are ubiquitous. Aeolian transport is probably limited by sand lithification causing shortage of saltation-capable material. Large impact events likely cause regional short-term spikes in aeolian transport by supplying a large amount of sand-size particles, as well as disintegration and activation of older indurated sand deposits. The data available are insufficient to understand whether the global aeolian sand transport occurs or not. More robust knowledge about aeolian transport on Venus is essential for future scientific exploration of the planet, in particular, for implementation and interpretation of geochemical studies of surface materials. High-resolution orbital radar imaging with local to regional coverage and desirable interferometric capabilities is the

Oil sands development and its impact on atmospheric wet deposition of air pollutants to the Athabasca Oil Sands Region, Alberta, Canada.

PubMed

Lynam, Mary M; Dvonch, J Timothy; Barres, James A; Morishita, Masako; Legge, Allan; Percy, Kevin

2015-11-01

Characterization of air pollutant deposition resulting from Athabasca oil sands development is necessary to assess risk to humans and the environment. To investigate this we collected event-based wet deposition during a pilot study in 2010-2012 at the AMS 6 site 30 km from the nearest upgrading facility in Fort McMurray, AB, Canada. Sulfate, nitrate and ammonium deposition was (kg/ha) 1.96, 1.60 and 1.03, respectively. Trace element pollutant deposition ranged from 2 × 10(-5) - 0.79 and exhibited the trend Hg < Se < As < Cd < Pb < Cu < Zn < S. Crustal element deposition ranged from 1.4 × 10(-4) - 0.46 and had the trend: La < Ce < Sr < Mn < Al < Fe < Mg. S, Se and Hg demonstrated highest median enrichment factors (130-2020) suggesting emissions from oil sands development, urban activities and forest fires were deposited. High deposition of the elements Sr, Mn, Fe and Mg which are tracers for soil and crustal dust implies land-clearing, mining and hauling emissions greatly impacted surrounding human settlements and ecosystems. Copyright © 2015 Elsevier Ltd. All rights reserved.

Identification of sources of tar balls deposited along the Southwest Caspian Coast, Iran using fingerprinting techniques.

PubMed

Shirneshan, Golshan; Bakhtiari, Alireza Riyahi; Memariani, Mahmoud

2016-10-15

In 2012, a significant number of tar balls occurred along the Southwest coasts of the Caspian Sea (Iran). Several oil fields of Turkmenistan, Azerbaijan and Iran might be sources of oil spills and lead to the formation of these tar balls. For source identification, 6 tar ball samples were collected from the Southwest beaches of the Caspian Sea and subjected to fingerprint analysis based on the distribution of the source-specific biomarkers of pentacyclic tri-terpanes and steranes. Comparing the diagenic ratios revealed that the tar balls were chemically similar and originated from the same source. Results of double ratio plots (e.g., C29/C30 versus ∑C31-C35/C30 and C28 αββ/(C27 αββ+C29 αββ) versus C29 αββ/(C27 αββ+C28 αββ)) in the tar balls and oils from Iran, Turkmenistan and Azerbaijan indicated that the tar balls might be the result of spills from Turkmenistan oil. Moreover, principle component analysis (PCA) using biomarker ratios on the tar balls and 20 crude oil samples from different wells of Azerbaijan, Iran and Turkmenistan oils showed that the tar balls collected at the Southwest beaches are highly similar to the Turkmenistan oil but one of the Azerbaijan oils (from Bahar field oils) was found to be also slightly close to the tar balls. The weathering characterizations based on the presence of UCM (unresolved complex mixture) and low/high molecular weight ratios (L/H) of alkanes and PAHs indicated the tar ball samples have been significantly influenced by natural weathering processes such as evaporation, photo-degradation and biodegradation. This is the first study of its kind in Iran to use fingerprinting for source identification of tar balls. Copyright © 2016 Elsevier B.V. All rights reserved.

The significance of discharge in the replenishment of sand bar deposits along the Colorado River through the Grand Canyon

NASA Astrophysics Data System (ADS)

Wiele, S.; Hazel, J.; Schmidt, J. C.; Melis, T.

2002-12-01

Topographic sandbar surveys, recovered scour chains, analysis of aerial photos, and modeling of sand deposition demonstrate that releases from Glen Canyon Dam greater than power-plant capacity (PPC; about 900 cubic meters per second) are significantly more effective than PPC-limited releases at redistributing sand from the channel bed to higher elevations along the channel margin. A release of 1,270 m3/s (1.4 times the PPC) for 7 days in 1996 tested the effectiveness with which sandbars could be restored by the manipulation of dam releases aimed at redistributing a limited sand supply. This high flow generally resulted in substantial increases in bar size, although some sandbars close to the dam eroded. Since 1996, releases for bar building and habitat maintenance (a 2-day release in 1997 and two 4-day releases in 2000) have been limited to PPC. Field measurements indicate that the 1996 release of 1,270 m3/s significantly increased the area and volume of sand deposits at elevations greater than the stage reached during typical post-dam flows. Minor aggradation occurred during the PPC flows. In 1996, the relative extent of erosion and deposition changed longitudinally downstream as evidenced by the area of substantial deposition exceeding that of erosion at sites further downstream. The number of bars that were substantially reworked, as measured by the number of bars that significantly increased or decreased in area at the elevation range of normal dam operations, was much greater at 1,270 m3/s than at 900 m3/s. Deposition from the 1,270 m3/s release persisted at many sites on a multi-year scale whereas deposition resulting from the PPC flows only lasted a few months. Minor deposition during PPC flows in 1997, however, was greatest in upstream reaches where bar erosion during normal flows had been more extensive. These observations show that deposition is sensitive to flow magnitude and depth of inundation as well as sand supply. Flow, sand transport, and bed

Coal tar phototherapy for psoriasis reevaluated: erythemogenic versus suberythemogenic ultraviolet with a tar extract in oil and crude coal tar

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lowe, N.J.; Wortzman, M.S.; Breeding, J.

1983-06-01

Recent studies have questioned the therapeutic value of coal tar versus ultraviolet (UV) radiation and their relative necessity in phototherapy for psoriasis. In this investigation, different aspects of tar phototherapy have been studied in single-blind bilateral paired comparison studies. The effects of 1% crude coal tar were compared with those of petrolatum in conjunction with erythemogenic and suberythemogenic doses of ultraviolet light (UVB) using a FS72 sunlamp tubed cabinet. Crude coal tar was clinically superior to petrolatum with suberythemogenic ultraviolet. With the erythemogenic UVB, petrolatum was equal in efficacy to crude coal tar. Suberythemogenic UVB was also used adjunctively tomore » compare the effects of a 5% concentration of a tar extract in an oil base to 5% crude coal tar in petrolatum or the oil base without tar. The tar extract in oil plus suberythemogenic UVB produced significantly more rapid improvement than the oil base plus UVB. The direct bilateral comparison of equal concentrations of tar extract in oil base versus crude coal tar in petrolatum in a suberythemogenic UV photo regimen revealed no statistical differences between treatments. In a study comparing tar extract in oil and the oil base without ultraviolet radiation, the tar extract in oil side responded more rapidly.« less

The Influences of Geologic Depositional Environments on Sand Boil Development, Tara Wildlife Lodge Area in Mississippi

DTIC Science & Technology

2016-03-01

ER D C/ G SL T R- 16 -7 The Influences of Geologic Depositional Environments on Sand Boil Development, Tara Wildlife Lodge Area in...client/default. ERDC/GSL TR-16-7 March 2016 The Influences of Geologic Depositional Environments on Sand Boil Development, Tara Wildlife Lodge...Army Corps of Engineers Washington, DC 20314-1000 ERDC/GSL TR-16-7 ii Abstract A comprehensive study of the subsurface geology in the Tara Wildlife

River of Sand

NASA Image and Video Library

2016-09-21

A dominant driver of surface processes on Mars today is aeolian (wind) activity. In many cases, sediment from this activity is trapped in low-lying areas, such as craters. Aeolian features in the form of dunes and ripples can occur in many places on Mars depending upon regional wind regimes. The Cerberus Fossae are a series of discontinuous fissures along dusty plains in the southeastern region of Elysium Planitia. This rift zone is thought to be the result of combined volcano-tectonic processes. Dark sediment has accumulated in areas along the floor of these fissures as well as inactive ripple-like aeolian bedforms known as "transverse aeolian ridges" (TAR). Viewed through HiRISE infrared color, the basaltic sand lining the fissures' floor stands out as deep blue against the light-toned dust covering the region. This, along with the linearity of the fissures and the wave-like appearance of the TAR, give the viewer an impression of a river cutting through the Martian plains. However, this river of sand does not appear to be flowing. Analyses of annual monitoring images of this region have not detected aeolian activity in the form of ripple migration thus far. http://photojournal.jpl.nasa.gov/catalog/PIA21063

Sedimentary processes associated with sand and boulder deposits formed by the 2011 Tohoku-oki tsunami at Sabusawa Island, Japan

NASA Astrophysics Data System (ADS)

Goto, Kazuhisa; Sugawara, Daisuke; Ikema, Satoko; Miyagi, Toyohiko

2012-12-01

This paper reports on the sedimentary processes of sand and boulder deposition at Sabusawa Island, Japan as a result of the 2011 Tohoku-oki tsunami. Boulders were composed of tuffaceous rocks and sourced from an earthquake-triggered slope failure as well as concrete fragments of seawall. They were scattered over the ground surface and did not form boulder ridges, although there was some local imbrication. The boulders were deposited on top of a sand layer indicating that the latter, possibly deposited from bed load, covered the ground surface first. This sand layer probably reduced friction allowing boulders to be transported more easily than might be expected across a hard ground with a high bottom friction. Sand deposits showed landward thinning and fining features, while the boulders showed a landward coarsening (tuffaceous boulders) or a landward fining (concrete boulders), indicating that large clasts were not necessarily scattered randomly but rather might have a clast size gradient with distance inland. These features are explained by the local topographic setting that constrained the directions of incoming and returning tsunami flows. Some clasts at the inland extent of the boulder field were covered by an upward fining sand layer. This feature suggests that the boulders were deposited prior to the suspended sands, with the latter subsequently laid down before the water level dropped below the top of the boulders. Such modern investigations of the sedimentary features of various sizes of grains and clasts immediately after a tsunami provide invaluable data for the reconstruction of inundation processes.

Event sand layers suggesting the possibility of tsunami deposits identified in the upper Holocene sequence nearby the Kuwana fault, central Japan

NASA Astrophysics Data System (ADS)

Niwa, Y.; Sugai, T.; Matsuzaki, H.

2012-12-01

The Kuwana fault is located on coastal area situated on inner part of the Ise Bay, central Japan, which opens to the Nankai Trough. This reverse fault displaces a late Pleistocene terrace surface with 1 to 2 mm/yr of average vertical slip rate, and a topset of delta at several meters, respectively. And, this fault is estimated to have generated two historical earthquakes (the AD 745 Tempyo and the AD 1586 Tensho earthquakes). We identified two event sand layers from upper Holocene sequence on the upthrown side of the Kuwana fault. Upper Holocene deposits in this study area show prograding delta sequence; prodelta mud, delta front sandy silt to sand, and flood plain sand/mud, respectively, from lower to upper. Two sand layers intervene in delta front sandy silt layer, respectively. Lower sand layer (S1) shows upward-coarsening succession, whereas upper sand layer (S2) upward-fining succession. These sand layers contain sharp contact, rip-up crust, and shell fragment, indicating strong stream flow. Radiocarbon ages show that these strong stream flow events occurred between 3000 and 1600 years ago. Decreasing of salinity is estimated from decreasing trend of electrical conductivity (EC) across S1. Based on the possibility that decreasing of salinity can be occurred by shallowing of water depth caused by coseismic uplift, and that S1 can be correlated with previously known faulting event on the Kuwana fault, S1 is considered to be tsunami deposits caused by faulting on the Kuwana fault. On the other hand, S2, which cannot be correlated with previously known faulting events on the Kuwana fault, may be tsunami deposits by ocean-trench earthquake or storm deposits. In the presentation, we will discuss more detail correlation of these sand deposits not only in the upthrown side of the Kuwana fault, but also downthrown side of the fault.

Metal catalysts for steam reforming of tar derived from the gasification of lignocellulosic biomass.

PubMed

Li, Dalin; Tamura, Masazumi; Nakagawa, Yoshinao; Tomishige, Keiichi

2015-02-01

Biomass gasification is one of the most important technologies for the conversion of biomass to electricity, fuels, and chemicals. The main obstacle preventing the commercial application of this technology is the presence of tar in the product gas. Catalytic reforming of tar appears a promising approach to remove tar and supported metal catalysts are among the most effective catalysts. Nevertheless, improvement of catalytic performances including activity, stability, resistance to coke deposition and aggregation of metal particles, as well as catalyst regenerability is greatly needed. This review focuses on the design and catalysis of supported metal catalysts for the removal of tar in the gasification of biomass. The recent development of metal catalysts including Rh, Ni, Co, and their alloys for steam reforming of biomass tar and tar model compounds is introduced. The role of metal species, support materials, promoters, and their interfaces is described. Copyright © 2014 Elsevier Ltd. All rights reserved.

Paleo-Environment and C-14 Dating: The Key to the Depositional Age of the Tha Chang and Related Sand Pits, Northeastern Thailand

NASA Technical Reports Server (NTRS)

Putthapiban, P.; Zolensky, M.; Jull, T.; Demartino, M.; Salyapongse, S.

2012-01-01

Tha Chang sand pits, Nakhon Ratchasima Province and many other sand pits in the area adjacent to the Mun River are characterized by their fluviatile environment in association with mass wasting deposits, along the paleo-river channel and the flood plain of the Mun River. Sediments of these deposits are characterized by clasts of various rock types especially the resistant ones with frequent big tree trunks, logs and wood fragments in different sizes and various stages of transformation from moldering stage to lignification and petrification. Widespread pyritization of the lower horizon suggests strongly reducing environment during burial. The Tha Chang deposits have been received much attention from geoscientists especially paleontologist communities, as they contain fragments of some distinct vertebrate species such as Stegadon sp., hominoid primate, rhinoceros Aceratherium and others. Based on the associated mammal fauna and hominoid fossils, the late Miocene ( 9 - 6 Ma) was given for the time of deposition of this sand and gravel unit. Some other reports believed that sediments and materials of these sand and gravel quarries (pits) were deposited by high-energy flood pulses contemporaneous with the tektites forming event during mid-Pleistocene at c. 0.8 Ma. Interpretation from Palynostratigraphical study suggested that the lower horizon of Tha Chang sand pit was deposited during Pliocene/Pleistocene period and the upper horizons are Pleistoncene/Holocene. It is crystal clear that all the fluviatile sediments including tektites and almost all fossil fragments being deposited in these sand pits were, likely a multiple times reworked materials. Only some old bamboo trees, some old crowling trees and fossils grasses observed on the old river bank are considered in situ. C-14 dating of 5 old wood specimens from Tha Chang Sand Pits, 15 old wood specimens from Chumpuang Sand Pits and one sample of old pottery from a Chumpuang Sand Pit were carried out in the NSF

Coastal deposits of heavy mineral sands; Global significance and US resources

USGS Publications Warehouse

Van Gosen, Bradley S.; Bleiwas, Donald I.; Bedinger, George M.; Ellefsen, Karl J.; Shah, Anjana K.

2016-01-01

Ancient and modern coastal deposits of heavy mineral sands (HMS) are the principal source of several heavy industrial minerals, with mining and processing operations on every continent except Antarctica. For example, HMS deposits are the main source of titanium feedstock for the titanium dioxide (TiO2) pigments industry, obtained from the minerals ilmenite (Fe2+TiO3), rutile (TiO2) and leucoxene (an alteration product of ilmenite). HMS deposits are also the principal source of zircon (ZrSiO4), from which zirconium dioxide (ZrO2) is obtained for uses mostly in refractory products. Sometimes monazite [(Ce,La,Nd,Th)PO4] is recovered as a byproduct mineral, sought for its rare earth elements and thorium (Ault and others, 2016; Sengupta and Van Gosen, 2016; Van Gosen and Tulsidas, 2016). 

Highstand shelf fans: The role of buoyancy reversal in the deposition of a new type of shelf sand body

USGS Publications Warehouse

Steel, Elisabeth; Simms, Alexander R.; Warrick, Jonathan; Yokoyama, Yusuke

2016-01-01

Although sea-level highstands are typically associated with sediment-starved continental shelves, high sea level does not hinder major river floods. Turbidity currents generated by plunging of sediment-laden rivers at the fluvial-marine interface, known as hyperpycnal flows, allow for cross-shelf transport of suspended sand beyond the coastline. Hyperpycnal flows in southern California have deposited six subaqueous fans on the shelf of the northern Santa Barbara Channel in the Holocene. Using eight cores and nine grab samples, we describe the deposits, age, and stratigraphic architecture of two fans in the Santa Barbara Channel. Fan lobes have up to 3 m of relief and are composed of multiple hyperpycnite beds ∼5 cm to 40 cm thick. Deposit architecture and geometry suggest the hyperpycnal flows became positively buoyant and lifted off the seabed, resulting in well-sorted, structureless, elongate sand lobes. Contrary to conventional sequence stratigraphic models, the presence of these features on the continental shelf suggests that active-margin shelves may locally develop high-quality reservoir sand bodies during sea-level highstands, and that such shelves need not be solely the site of sediment bypass. These deposits may provide a Quaternary analogue to many well-sorted sand bodies in the rock record that are interpreted as turbidites but lack typical Bouma-type features.

Approach to Assessing the Effects of Aerial Deposition on Water Quality in the Alberta Oil Sands Region.

PubMed

Dayyani, Shadi; Daly, Gillian; Vandenberg, Jerry

2016-02-01

Snow cover forms a porous medium that acts as a receptor for aerially deposited polycyclic aromatic hydrocarbons (PAHs) and metals. The snowpack, acting as a temporary storage reservoir, releases contaminants accumulating over the winter during a relatively short melt period. This process could result in elevated concentrations of contaminants in melt water. Recent studies in the Alberta oil sands region have documented increases in snowpack and lake sediment concentrations; however, no studies have addressed the fate and transport of contaminants during the snowmelt period. This study describes modelling approaches that were developed to assess potential effects of aerially deposited PAHs and metals to snowpack and snowmelt water concentrations. The contribution of snowmelt to freshwater PAH concentrations is assessed using a dynamic, multi-compartmental fate model, and the contribution to metal concentrations is estimated using a mass-balance approach. The modelling approaches described herein were applied to two watersheds in the Alberta oil sands region for two planned oil sands developments. Accumulation of PAHs in a lake within the deposition zone was also modelled for comparison to observed concentrations.

Hydrodynamic implications of textural trends in sand deposits of the 2004 tsunami in Sri Lanka

USGS Publications Warehouse

Morton, R.A.; Goff, J.R.; Nichol, S.L.

2008-01-01

Field observations and sediment samples at a coastal-plain setting in southeastern Sri Lanka were used to document the erosional and depositional impacts of the 2004 Indian Ocean tsunami and to interpret the hydrodynamic processes that produced an extensive sand-sheet deposit. Tsunami deposit thicknesses ranged from 6 to 22??cm with thickness being controlled partly by antecedent topography. The deposit was composed of coarse to medium sand organized into plane-parallel laminae and a few laminasets. Vertical textural trends showed an overall but non-systematic upward fining and upward thinning of depositional units with an upward increase in heavy-mineral laminations at some locations. Repeated patterns in the vertical textural trends (upward fining, upward coarsening, uniform) were used to subdivide and correlate the deposit into five hydro-textural stratigraphic units. The depositional units were linked to hydrodynamic processes and upcurrent conditions, such as rates of sediment supply and composition of the sediment sources. Vertical changes in grain-size distributions recorded the depositional phases associated with flow acceleration, initial unsteady pulsating flow, relatively stable and uniform flow, flow deceleration, slack water, and return flow or flow redirection. Study results suggest that vertical textural trends from multiple cross-shore sections can be used to interpret complex tsunami flow histories, but at the location examined, interpretation of the lateral textural trends did not provide a basis for identifying the correct sediment transport pathways because flow near the landward boundary was multidirectional.

A new depositional model for sand-rich loess on the Buckley Flats outwash plain, northwestern Lower Michigan

NASA Astrophysics Data System (ADS)

Nyland, Kelsey E.; Schaetzl, Randall J.; Ignatov, Anthony; Miller, Bradley A.

2018-04-01

Loess was first studied in Michigan on the Buckley Flats, where outwash, overlain by ≈70 cm of loamy sediment, was originally interpreted as loess mixed with underlying sands. This paper re-evaluates this landscape through a spatial analysis of data from auger samples and soil pits. To better estimate the loamy sediment's initial textures, we utilized "filtered" laser diffraction data, which remove much of the coarser sand data. Textures of filtered silt data for the loamy sediment are similar to loess. The siltiest soils are found in the low-relief, central part of the Flats. Spatial analyses revealed that many silt fractions are nearly uniformly distributed, suggesting that the loess was not derived from a single source. The previous depositional model for the loamy mantle relied on loessfall followed by pedoturbation, but does not explain (1) the variation in sand contents across the Flats, or (2) the abrupt contact below the loamy mantle. This contact suggests that the outwash was frozen when the sediments above were deposited. Deep gullies at the western margins of the Flats were likely cut as permafrost facilitated runoff. Our new model for the origin of the loamy mantle suggests that the sands on the uplands were generated from eroding gullies and saltated onto the uplands along with loess that fell more widely. Sands saltating to the west of the Flats may have entrained some silts, facilitating loessfall downwind. At most sites, the loamy mantle gets increasingly silty near the surface, suggesting that saltation ended before loess deposition.

Tar removal during the fluidized bed gasification of plastic waste.

PubMed

Arena, Umberto; Zaccariello, Lucio; Mastellone, Maria Laura

2009-02-01

A recycled polyethylene was fed in a pilot plant bubbling fluidized bed gasifier, having an internal diameter of 0.381 m and a maximum feeding capacity of 90 kg/h. The experimental runs were carried out under various operating conditions: the bed temperature was kept at about 850 degrees C, the equivalence ratio varied between 0.2 and 0.35, the amount of bed material was between 131 and 215 kg, the fluidizing velocity was between 0.5 and 0.7 m/s, quartz sand and olivine were used as bed material, and air and steam were used as fluidizing reactants. The results confirm that the tar removal treatments applied inside the gasifier (primary methods) can eliminate or strongly reduce the need for a further downstream cleanup of the syngas. In particular, the utilization of a natural olivine as an in situ tar reduction agent remarkably improves the quality of the product gas, in terms of both high hydrogen volumetric fraction and larger syngas yield.

Deposit model for heavy-mineral sands in coastal environments: Chapter L in Mineral deposit models for resource assessment

USGS Publications Warehouse

Van Gosen, Bradley S.; Fey, David L.; Shah, Anjana K.; Verplanck, Philip L.; Hoefen, Todd M.

2014-01-01

Regional exploration for deposits of heavy-mineral sands can utilize the analyses of stream sediment samples for Ti, Hf, the rare earth elements, Th, and U, and geophysical surveys, particularly radiometric (gamma-ray spectrometry for K, U, and Th) and magnetic methods. Geophysical anomalies may be small, and surveys are generally more successful when conducted close to sources of interest.

Investigation of Reversing Sand Dunes at the Bruneau Dunes, Idaho, as Analogs for Features on Mars

NASA Astrophysics Data System (ADS)

Zimbelman, J. R.; Scheidt, S. P.

2012-12-01

The Bruneau Dunes in south-central Idaho include several large reversing sand dunes located within a cut-off meander of the Snake River. These dunes include the largest single-structured sand dune present in North America. Wind records from the Remote Automated Weather Station (RAWS) installation at the Mountain Home Air Force Base, which is ~21 km NW of the Bruneau Dunes, have proved to be very helpful in assessing the regional wind patterns at this section of the western Snake River Plains province; a bimodal wind regime is present, with seasonal changes of strong (sand-moving) winds blowing from either the northwest or the southeast. During April of 2011, we obtained ten precision topographic surveys across the southernmost reversing dune using a Differential Global Positioning System (DGPS). The DGPS data document the shape of the dune going from a low, broad sand ridge at the southern distal end of the dune to the symmetrically shaped 112-m-high central portion of the dune, where both flanks of the dune consist of active slopes near the angle of repose. These data will be useful in evaluating the reversing dune hypothesis proposed for enigmatic features on Mars called Transverse Aeolian Ridges (TARs), which could have formed either as large mega-ripples or small sand dunes. The symmetric profiles across TARs with heights greater than 1 m are more consistent with measured profiles of reversing sand dunes than with measured profiles of mega-ripples (whose surfaces are coated by large particles ranging from coarse sand to gravel, moved by saltation-induced creep). Using DGPS to monitor changes in the three-dimensional location of the crests of the reversing dunes at the Bruneau Dunes should provide a means for estimating the likely timescale for changes of TAR crests if the Martian features are indeed formed in the same manner as reversing sand dunes on Earth.

Retention in Treated Wastewater Affects Survival and Deposition of Staphylococcus aureus and Escherichia coli in Sand Columns

PubMed Central

Li, Jiuyi; Zhao, Xiaokang; Tian, Xiujun; Li, Jin; Sjollema, Jelmer

2015-01-01

The fate and transport of pathogenic bacteria from wastewater treatment facilities in the Earth's subsurface have attracted extensive concern over recent decades, while the impact of treated-wastewater chemistry on bacterial viability and transport behavior remains unclear. The influence of retention time in effluent from a full-scale municipal wastewater treatment plant on the survival and deposition of Staphylococcus aureus and Escherichia coli strains in sand columns was investigated in this paper. In comparison to the bacteria cultivated in nutrient-rich growth media, retention in treated wastewater significantly reduced the viability of all strains. Bacterial surface properties, e.g., zeta potential, hydrophobicity, and surface charges, varied dramatically in treated wastewater, though no universal trend was found for different strains. Retention in treated wastewater effluent resulted in changes in bacterial deposition in sand columns. Longer retention periods in treated wastewater decreased bacterial deposition rates for the strains evaluated and elevated the transport potential in sand columns. We suggest that the wastewater quality should be taken into account in estimating the fate of pathogenic bacteria discharged from wastewater treatment facilities and the risks they pose in the aquatic environment. PMID:25595758

Origin and prospectivity of heavy mineral enriched sand deposits along the Somaliland coastal areas

NASA Astrophysics Data System (ADS)

Ali, M. Y.; Hibberd, P.; Stoikovich, B.

2018-04-01

Sixty-one heavy mineral enriched samples along the Somaliland coast from Eil Sheikh to Ras Khatib, a distance of about 130 km, were analyzed using X-ray Fluorescence, X-ray Diffraction and SEM-EDS techniques. This study reveals that a considerable amount of heavy minerals is present along the Somaliland coast and confirms the presence of high concentration titanium and iron bearing minerals. However, the backshore deposits in the mouths of Waaheen and Biyo Gure ephemeral rivers as well as raised paleo-beaches in the east of port city of Berbera demonstrate the highest level of titaniferous heavy minerals with most samples showing concentration greater than 50 wt %. The titanium detected in geochemical analysis occurs in the form of ilmenite, rutile, titanite and titaniferous magnetite. Also, present in minor or trace amounts, are garnet, zircon and monazite. Heavy mineral accumulations in the east and west of Berbera have different mineralogical assemblages. The east of Berbera is dominated by quartz with moderate concentration of plagioclase, K-feldspar, magnetite, hematite and titanium bearing minerals, whereas in the west of Berbera, the dominant minerals are quartz, K-feldspar and plagioclase with variable proportions of ilmenite, rutile, mica, amphibole and pyroxene. These variations in mineral assemblages suggest different composition of the catchment areas that supply sediment to these deposits. The catchment area in the east of Berbera consists mainly of Proterozoic crystalline basement of the Qabri Bahar complex, Gabbro-Synenite belt and granitic intrusions that outcrop in Hudiso, Tulo Dibijo and surrounding areas. The primary sources of heavy minerals in the west of Berbera comprise of high-grade metamorphic rocks of the Mora and Qabri Bahar complexes as well as the Miocene volcanics that outcrop in Laferug and Hagabo areas. The heavy mineral sand deposits observed along the Somaliland coast have the potential to provide commercially important heavy

Maps showing characteristics of the Cabo Rojo West offshore sand deposit, southwestern Puerto Rico

USGS Publications Warehouse

Trumbull, James V.A.; Trias, Juan L.

1982-01-01

This report presents detailed information on a deposit of well-sorted coarse calcareous sand in water depths of 10-20 m in an area between 1 and 6 km west and southwest fo the promontory of Cabo Rojo, the southwesternmost corner of Puerto Rico. 

Low-tar and high-tar cigarettes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Holt, P.G.; Chalmer, J.E.; Roberts, L.M.

Mice were exposed for 7 to 8 minutes on weekdays to fresh smoke from high-tar (HT) or low-tar (LT) cigarettes for varying periods of up to 36 weeks. Mice exposed to HT cigarettes exhibited more marked alterations in humoral immune responsiveness, hematological profiles, and pulmonary pathologic findings than those exposed to LT cigarettes. However, cell-mediated immune responsiveness to both bacterial and tumor-specific antigens was depressed similarly in animals exposed to HT or LT cigarettes. Furthermore, the growth rates of subcutaneously established tumors were enhanced similarly in the two groups, with respect to those in control animals.

Influence of the presence of PAHs and coal tar on naphthalene sorption in soils

NASA Astrophysics Data System (ADS)

Bayard, Rémy; Barna, Ligia; Mahjoub, Borhane; Gourdon, Rémy

2000-11-01

concentrations (about 120 mg/kg) in the soil. In contrast, experiments carried out with coal tar particles revealed a significant effect. Naphthalene sorption appeared to be proportional to the amount of coal tar added to the sand or soil, and a much higher affinity of naphthalene for XOM ( Koc above 2000 cm 3/g) than SOM ( Koc around 300 cm 3/g) was observed. Naphthalene transport in the columns of sand or soil spiked with coal tar particles was simulated very satisfactorily with a dual double-domain model. Around 90% of naphthalene retention by coal tar was found to occur within the organic phase, suggesting a phase partition process which may be explained by the amorphous nature of the XOM and its extreme affinity for naphthalene. For SOM, however, which is present as porous microaggregates of clay and humic substances, with less affinity for naphthalene, only 1/3 of naphthalene retention was found to occur within the organic phase, underlining the significant role of surface adsorption in the short term behavior of naphthalene in soil. For longer contact times, the model simulations proposed in the present study should be coupled to slow sorption, aging and biodegradation models to describe long-term behavior of naphthalene in soil-tar-water systems.

Effects of sand burial on dew deposition on moss soil crust in a revegetated area of the Tennger Desert, Northern China

NASA Astrophysics Data System (ADS)

Jia, Rong-liang; Li, Xin-rong; Liu, Li-chao; Pan, Yan-xia; Gao, Yan-hong; Wei, Yong-ping

2014-11-01

Sand burial and dew deposition are two fundamental phenomena profoundly influencing biological soil crusts in desert areas. However, little information is available regarding the effects of sand burial on dew deposition on biological soil crusts in desert ecosystems. In this study, we evaluated the effects of sand burial at depths of 0 (control), 0.5, 1, 2 and 4 mm on dew formation and evaporation of three dominant moss crusts in a revegetated area of the Tengger Desert (Northern China) in 2010. The results revealed that sand burial significantly decreased the amount of dew deposited on the three moss crust types by acting as a semi-insulator retarding the dew formation and evaporation rates. The changes in surface temperature cannot fully explain the variations of the formation and evaporation rates of dew by moss crusts buried by sand. The extension of dew retention time was reflected by the higher dew ratios (the ratio of dew amount at a certain time to the maximum value in a daily course) in the daytime, and may to some extent have acted as compensatory mechanisms that diminished the negative effects of the reduction of dew amount induced by sand burial of moss crusts. The resistances to reduction of dewfall caused by sand burial among the three moss crusts were also compared and it was found that Bryum argenteum crust showed the highest tolerance, followed by crusts dominated by Didymodon vinealis and Syntrichia caninervis. This sequence corresponds well with the successional order of the three moss crusts in the revegetated area, thereby suggesting that resistance to reduction of dewfall may act as one mechanism by which sand burial drives the succession of moss crusts in desert ecosystems. This side effect of dew reduction induced by sand burial on biological soil crusts should be considered in future ecosystem construction and management of desert area.

Quantification of annual sediment deposits for sustainable sand management in Aghanashini river estuary.

PubMed

Ramachandra, T V; Vinay, S; Subash Chandran, M D

2018-01-15

Sedimentation involving the process of silt transport also carries nutrients from upstream to downstream of a river/stream. Sand being one of the important fraction of these sediments is extracted in order to cater infrastructural/housing needs in the region. This communication is based on field research in the Aghanshini river basin, west coast of India. Silt yield in the river basin and the sedimentation rate assessed using empirical techniques supplemented with field quantifications using soundings (SONAR), show the sediment yield of 1105-1367 kilo cum per year and deposition of sediment of 61 (2016) to 71 (2015) cm. Quantifications of extractions at five locations, reveal of over exploitation of sand to an extent of 30% with damages to the breeding ground of fishes, reduced productivity of bivalves, etc., which has affected dependent people's livelihood. This study provides vital insights towards sustainable sand harvesting through stringent management practices. Copyright © 2017 Elsevier Ltd. All rights reserved.

Retrogressive Failures in Sand Deposits of the Mississippi River. Report 1. Field Investigations, Laboratory Studies and Analysis of the Hypothesized Failure Mechanism

DTIC Science & Technology

1988-06-01

densities of Mississippi River point bar sands . 73. It is particularly conclusive to compare the available critical void ratio data for point bar sands on... River encounters the difficulty that the density of large parts of Zone A sands is between the upper and lower critical densities . All laboratory... sands of the Lower Mississippi River point bar deposits generally contain some strata of subcritical density , and the initial tendenc% of such sands

Topical tar: Back to the future

DOE Office of Scientific and Technical Information (OSTI.GOV)

Paghdal, K.V.; Schwartz, R.A.

2009-08-15

The use of medicinal tar for dermatologic disorders dates back to the ancient times. Although coal tar is utilized more frequently in modern dermatology, wood tars have also been widely employed. Tar is used mainly in the treatment of chronic stable plaque psoriasis, scalp psoriasis, atopic dermatitis, and seborrheic dermatitis, either alone or in combination therapy with other medications, phototherapy, or both. Many modifications have been made to tar preparations to increase their acceptability, as some dislike its odor, messy application, and staining of clothing. One should consider a tried and true treatment with tar that has led to clearingmore » of lesions and prolonged remission times. Occupational studies have demonstrated the carcinogenicity of tar; however, epidemiologic studies do not confirm similar outcomes when used topically. This article will review the pharmacology, formulations, efficacy, and adverse effects of crude coal tar and other tars in the treatment of selected dermatologic conditions.« less

Characteristics of PAH tar oil contaminated soils-Black particles, resins and implications for treatment strategies.

PubMed

Trellu, Clément; Miltner, Anja; Gallo, Rosita; Huguenot, David; van Hullebusch, Eric D; Esposito, Giovanni; Oturan, Mehmet A; Kästner, Matthias

2017-04-05

Tar oil contamination is a major environmental concern due to health impacts of polycyclic aromatic hydrocarbons (PAH) and the difficulty of reaching acceptable remediation end-points. Six tar oil-contaminated soils with different industrial histories were compared to investigate contamination characteristics by black particles. Here we provide a simple method tested on 6 soils to visualize and identify large amounts of black particles (BP) as either solid aggregates of resinified and weathered tar oil or various wood/coke/coal-like materials derived from the contamination history. These materials contain 2-10 times higher PAH concentrations than the average soil and were dominantly found in the sand fraction containing 42-86% of the total PAH. The PAH contamination in the different granulometric fractions was directly proportional to the respective total organic carbon content, since the PAH were associated to the carbonaceous particulate materials. Significantly lower (bio)availability of PAH associated to these carbonaceous phases is widely recognized, thus limiting the efficiency of remediation techniques. We provide a conceptual model of the limited mass transfer of PAH from resinated tar oil phases to the water phase and emphasize the options to physically separate BP based on their lower bulk density and slower settling velocity. Copyright © 2017 Elsevier B.V. All rights reserved.

Deposition of Suspended Clay to Open and Sand-Filled Framework Gravel Beds in a Laboratory Flume

NASA Astrophysics Data System (ADS)

Mooneyham, Christian; Strom, Kyle

2018-01-01

Pulses of fine sediment composed of sand, silt, and clay can be introduced to gravel bed rivers through runoff from burn-impacted hillslopes, landslides, bank failure, or the introduction of reservoir sediment as a result of sluicing or dam decommissioning. Here we present a study aimed at quantifying exchange between suspensions of clay and gravel beds. The questions that motivate the work are: how do bed roughness and pore space characteristics, shear velocity (u∗), and initial concentration (C0) affect clay deposition on or within gravel beds? Where does deposition within these beds occur, and can deposited clay be resuspended while the gravel is immobile? We examine these questions in a laboratory flume using acrylic, open-framework gravel, and armored sand-gravel beds under conditions of varying u∗ and C0. Deposition of clay occurred to all beds (even with Rouse numbers ˜ 0.01). We attribute deposition under full suspension conditions to be an outcome of localized protected zones where clay can settle and available pore space in the bed. For smooth wall cases, protection came from the viscous wall region and the development of bed forms; for the rough beds, protection came from separation zones and low-velocity pore spaces. Bed porosity was the strongest influencer of nondimensional deposition rate; deposition increased with porosity. Deposition was inversely related to u∗ for the acrylic bed runs; no influence of u∗ was found for the porous bed runs. Increases in discharge resulted in resuspension of clay from acrylic beds; no resuspension was observed in the porous bed runs.

Tracing industrial sulfur emissions in atmospheric sulfate deposition in the Athabasca Oil Sands Region, Alberta, Canada

Treesearch

Bernadette C. Proemse; Bernhard Mayer; Mark E. Fenn

2012-01-01

Anthropogenic S emissions in the Athabasca oil sands region (AOSR) in Alberta, Canada, affect SO4 deposition in close vicinity of industrial emitters. Between May 2008 and May 2009, SO4-S deposition was monitored using open field bulk collectors at 15 sites and throughfall collectors at 14 sites at distances between 3 and 113 km from one of the major emission stacks in...

Identification of source locations for atmospheric dry deposition of heavy metals during yellow-sand events in Seoul, Korea in 1998 using hybrid receptor models

NASA Astrophysics Data System (ADS)

Han, Young-Ji; Holsen, Thomas M.; Hopke, Philip K.; Cheong, Jang-Pyo; Kim, Ho; Yi, Seung-Muk

2004-10-01

Elemental dry deposition fluxes were measured using dry deposition plates from March to June 1998 in Seoul, Korea. During this spring sampling period several yellow-sand events characterized by long-range transport from China and Mongolia impacted the area. Understanding the impact of yellow-sand events on atmospheric dry deposition is critical to managing the heavy metal levels in the environment in Korea. In this study, the measured flux of a primarily crustal metal, Al and an anthropogenic metal, Pb was used with two hybrid receptor models, potential source contribution function (PSCF) and residence time weighted concentration (RTWC) for locating sources of heavy metals associated with atmospheric dry deposition fluxes during the yellow-sand events in Seoul, Korea. The PSCF using a criterion value of the 75th percentile of the measured dry deposition fluxes and RTWC results using the measured elemental dry deposition fluxes agreed well and consistently showed that there were large potential source areas in the Gobi Desert in China and Mongolia and industrial areas near Tianjin, Tangshan, and Shenyang in China. Major industrial areas of Shenyang, Fushun, and Anshan, the Central China loess plateau, the Gobi Desert, and the Alashan semi-desert in China were identified to be major source areas for the measured Pb flux in Seoul, Korea. For Al, the main industrial areas of Tangshan, Tianjin and Beijing, the Gobi Desert, the Alashan semi-desert, and the Central China loess plateau were found to be the major source areas. These results indicate that both anthropogenic sources such as industrial areas and natural sources such as deserts contribute to the high dry deposition fluxes of both Pb and Al in Seoul, Korea during yellow-sand events. RTWC resolved several high potential source areas. Modeling results indicated that the long-range transport of Al and Pb from China during yellow-sand events as well as non-yellow-sand spring daytimes increased atmospheric dry

Differential Effects of High Atmospheric N and S Deposition on Bog Plant/Lichen Tissue and Porewater Chemistry across the Athabasca Oil Sands Region.

PubMed

Wieder, R Kelman; Vile, Melanie A; Scott, Kimberli D; Albright, Cara M; McMillen, Kelly J; Vitt, Dale H; Fenn, Mark E

2016-12-06

Oil extraction and development activities in the Athabasca Oil Sands Region of northern Alberta, Canada, release NO x , SO x , and NH y to the atmosphere, ultimately resulting in increasing N and S inputs to surrounding ecosystems through atmospheric deposition. Peatlands are a major feature of the northern Alberta landscape, with bogs covering 6-10% of the land area, and fens covering 21-53%. Bulk deposition of NH 4 + -N, NO 3 - -N, dissolved inorganic N (DIN), and SO 4 2- -S, was quantified using ion-exchange resin collectors deployed at 23 locations, over 1-6 years. The results reveal maximum N and S deposition of 9.3 and 12.0 kg ha -1 yr -1 , respectively, near the oil sands industrial center (the midpoint between the Syncrude and Suncor upgrader stacks), decreasing with distance to a background deposition of 0.9 and 1.1 kg ha -1 yr -1 , respectively. To assess potential influences of high N and S deposition on bogs, we quantified N and S concentrations in tissues of two Sphagnum species, two lichen species, and four vascular plant species, as well as surface porewater concentrations of H + , NH 4 + -N, NO 3 - -N, SO 4 2- -S and dissolved organic N in 19 ombrotrophic bogs, distributed across a 3255 km 2 sampling area surrounding the oil sands industrial center. The two lichen species (Evernia mesomorpha and Cladonia mitis), two vascular plant species (Rhododendron groenlandicum and Picea mariana), and to a lesser extent one moss (Sphagnum fuscum), showed patterns of tissue N and S concentrations that were (1) highest near the oil sands industrial center and (2) positively correlated with bulk deposition of N or S. Concentrations of porewater H + and SO 4 2- -S, but not of NH 4 + -N, NO 3 - -N, DIN, or dissolved inorganic N, also were higher near the oil sands industrial center than at more distant locations. The oil sands region of northern Alberta is remote, with few roads, posing challenges to the monitoring of oil sands-related N and S deposition

Spatial variation in deposition rate coefficients of an adhesion-deficient bacterial strain in quartz sand.

PubMed

Tong, Meiping; Camesano, Terri A; Johnson, William P

2005-05-15

The transport of bacterial strain DA001 was examined in packed quartz sand under a variety of environmentally relevant ionic strength and flow conditions. Under all conditions, the retained bacterial concentrations decreased with distance from the column inlet at a rate that was faster than loglinear, indicating that the deposition rate coefficient decreased with increasing transport distance. The hyperexponential retained profile contrasted againstthe nonmonotonic retained profiles that had been previously observed for this same bacterial strain in glass bead porous media, demonstrating that the form of deviation from log-linear behavior is highly sensitive to system conditions. The deposition rate constants in quartz sand were orders of magnitude below those expected from filtration theory, even in the absence of electrostatic energy barriers. The degree of hyperexponential deviation of the retained profiles from loglinear behavior did not decrease with increasing ionic strength in quartz sand. These observations demonstrate thatthe observed low adhesion and deviation from log-linear behavior was not driven by electrostatic repulsion. Measurements of the interaction forces between DA001 cells and the silicon nitride tip of an atomic force microscope (AFM) showed that the bacterium possesses surface polymers with an average equilibrium length of 59.8 nm. AFM adhesion force measurements revealed low adhesion affinities between silicon nitride and DA001 polymers with approximately 95% of adhesion forces having magnitudes < 0.8 nN. Steric repulsion due to surface polymers was apparently responsible for the low adhesion to silicon nitride, indicating that steric interactions from extracellular polymers controlled DA001 adhesion deficiency and deviation from log-linear behavior on quartz sand.

Catalytic decomposition of tar derived from wood waste pyrolysis using Indonesian low grade iron ore as catalyst

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wicakso, Doni Rahmat; Chemical Engineering Department, Faculty of Engineering, Gadjah Mada University, Jalan Grafika No. 2 Bulaksumur, Yogyakarta, 55281; Sutijan

Low grade iron ore can be used as an alternative catalyst for bio-tar decomposition. Compared to other catalysts, such as Ni, Rd, Ru, Pd and Pt, iron ore is cheaper. The objective of this research was to investigate the effect of using low grade iron ore as catalyst for tar catalytic decomposition in fixed bed reactor. Tar used in this experiment was pyrolysis product of wood waste while the catalyst was Indonesian low grade iron ore. The variables studied were temperatures between 500 – 600 °C and catalyst weight between 0 – 40 gram. The first step, tar was evaporatedmore » at 450 °C to produce tar vapor. Then, tar vapor was flowed to fixed bed reactor filled low grade iron ore. Gas and tar vapor from reactor was cooled, then the liquid and uncondensable gas were analyzed by GC/MS. The catalyst, after experiment, was weighed to calculate total carbon deposited into catalyst pores. The results showed that the tar components that were heavy and light hydrocarbon were decomposed and cracked within the iron ore pores to from gases, light hydrocarbon (bio-oil) and carbon, thus decreasing content tar in bio-oil and increasing the total gas product. In conclusion, the more low grade iron ore used as catalyst, the tar content in the liquid decrease, the H{sup 2} productivity increased and calorimetric value of bio-oil increased.« less

Effect of different-sized colloids on the transport and deposition of titanium dioxide nanoparticles in quartz sand.

PubMed

Cai, Li; Peng, Shengnan; Wu, Dan; Tong, Meiping

2016-01-01

Colloids (non-biological and biological) with different sizes are ubiquitous in natural environment. The investigations regarding the influence of different-sized colloids on the transport and deposition behaviors of engineered-nanoparticles in porous media yet are still largely lacking. This study investigated the effects of different-sized non-biological and biological colloids on the transport of titanium dioxide nanoparticles (nTiO2) in quartz sand under both electrostatically favorable and unfavorable conditions. Fluorescent carboxylate-modified polystyrene latex microspheres (CML) with sizes of 0.2-2 μm were utilized as model non-biological colloids, while Gram-negative Escherichia coli (∼ 1 μm) and Gram-positive Bacillus subtilis (∼ 2 μm) were employed as model biological colloids. Under the examined solution conditions, both breakthrough curves and retained profiles of nTiO2 with different-sized CML particles/bacteria were similar as those without colloids under favorable conditions, indicating that the copresence of model colloids in suspensions had negligible effects on the transport and deposition of nTiO2 under favorable conditions. In contrast, higher breakthrough curves and lower retained profiles of nTiO2 with CML particles/bacteria relative to those without copresent colloids were observed under unfavorable conditions. Clearly, the copresence of model colloids increased the transport and decreased the deposition of nTiO2 in quartz sand under unfavorable conditions (solution conditions examined in present study). Both competition of deposition sites on quartz sand surfaces and the enhanced stability/dispersion of nTiO2 induced by copresent colloids were found to be responsible for the increased nTiO2 transport with colloids under unfavorable conditions. Moreover, the smallest colloids had the highest coverage on sand surface and most significant dispersion effect on nTiO2, resulting in the greatest nTiO2 transport. Copyright © 2015. Published

Environmental consequences of oil production from oil sands

NASA Astrophysics Data System (ADS)

Rosa, Lorenzo; Davis, Kyle F.; Rulli, Maria C.; D'Odorico, Paolo

2017-02-01

Crude oil from oil sands will constitute a substantial share of future global oil demand. Oil sands deposits account for a third of globally proven oil reserves, underlie large natural forested areas, and have extraction methods requiring large volumes of freshwater. Yet little work has been done to quantify some of the main environmental impacts of oil sands operations. Here we examine forest loss and water use for the world's major oil sands deposits. We calculate actual and potential rates of water use and forest loss both in Canadian deposits, where oil sands extraction is already taking place, and in other major deposits worldwide. We estimated that their exploitation, given projected production trends, could result in 1.31 km3 yr-1 of freshwater demand and 8700 km2 of forest loss. The expected escalation in oil sands extraction thus portends extensive environmental impacts.

Relation Between PAHs and Coal-Tar-Based Pavement Sealant in Urban Environments (Invited)

NASA Astrophysics Data System (ADS)

Mahler, B. J.; van Metre, P. C.

2010-12-01

Since 2003, coal-tar-based sealant products have come under increased scrutiny as a source of PAHs in urban environments. Sealant (or sealcoat) is the black, shiny substance often applied to asphalt pavement, in particular parking lots and driveways, for esthetic and maintenance purposes. Coal-tar-based sealant, one of the two primary pavement sealant types on the market, typically is 20-35 percent coal-tar pitch, a known carcinogen that is more than 50 percent polycyclic aromatic hydrocarbons (PAHs). The PAH content of the coal-tar-based sealant product is about 1,000 times that of a similar, asphalt-based product, on average. This difference is reflected in regional differences in sealant use and PAH concentrations in pavement dust. In the central and eastern U.S., where the coal-tar-based formulation is prevalent, ΣPAH in mobile particles from sealed pavement have been shown to be about 1,000 times higher than in the western U.S., where the asphalt-based formulation is prevalent (the median ΣPAH concentrations are 2,200 mg/kg in the central and eastern U.S. and 2.1 mg/kg in the western U.S.). Source apportionment modeling indicates that, in the central and eastern U.S., particles from sealed pavement are contributing the majority of the PAHs in recently deposited (post-1990) lake sediment, with implications for ecological health, and that coal-tar-based sealant is the primary cause of upward trends in PAHs in U.S. urban lakes. From the standpoint of human health, research indicates that mobile particles from parking lots with coal-tar-based sealant are tracked indoors, resulting in elevated PAH concentrations in house dust. Coal-tar-based sealcoat being applied to an asphalt parking lot at the University of Texas Pickle Research Center.

Atmospheric dry deposition of sulfur and nitrogen in the Athabasca Oil Sands Region, Alberta, Canada

Treesearch

Yu-Mei Hsu; Andrzej Bytnerowicz; Mark E. Fenn; Kevin E. Percy

2016-01-01

Due to the potential ecological effects on terrestrial and aquatic ecosystems from atmospheric deposition in the Athabasca Oil Sands Region (AOSR), Alberta, Canada, this study was implemented to estimate atmospheric nitrogen (N) and sulfur (S) inputs. Passive samplers were used to measure ambient concentrations of ammonia (NH3), nitrogen dioxide...

Techniques for assessing sand and gravel resources in glaciofluvial deposits; an example using the surficial geologic map of the Loudon Quadrangle, Merrimack and Belknap counties, New Hampshire

USGS Publications Warehouse

Sutphin, David M.; Drew, Lawrence J.; Fowler, Brian K.; Goldsmith, Richard

2002-01-01

A method for estimating the sand and gravel resources in glaciofluvial systems has been developed based on surficial mapping techniques that use the morphosequence concept and geographic information systems (GIS). Two different strategies are used to estimate gravel resources. One strategy estimates the sand and gravel resources contained in esker deposits; the other, which is more dependent on GIS, estimates resources in non-esker deposits. An attempt has been made to determine which deposits are sterilized; that is, those beneath the water table, adjacent to streams or roads, or encroached on by urbanization. Preliminary estimates using these methods indicate that about 158,000,000 m3 (206,000,000 yd3) of sand and gravel are present in the Soucook River valley part of the Loudon, N.H., 7.5-minute quadrangle. About 64,500,000 m3 (84,400,000 yd3) of these materials are in deposits above the water table. About 26 percent of the sand and gravel resources above the water table are unlikely to be mined because they have been sterilized. Of the remaining resources, 479,000 m3 (627,000 yd3) of gravel and 1,120,000 m3 (1,460,000 yd3) of sand are in esker deposits, and 9,400,000 m3 (12,300,000 yd3) of gravel and 38,300,000 m3 (50,100,000 yd3) of sand are in stratified non-esker deposits. With the addition of new well data, newer and more accurate estimates are possible.

Modeling of Grain Size Distribution of Tsunami Sand Deposits in V-shaped Valley of Numanohama During the 2011 Tohoku Tsunami

NASA Astrophysics Data System (ADS)

Gusman, A. R.; Satake, K.; Goto, T.; Takahashi, T.

2016-12-01

Estimating tsunami amplitude from tsunami sand deposit has been a challenge. The grain size distribution of tsunami sand deposit may have correlation with tsunami inundation process, and further with its source characteristics. In order to test this hypothesis, we need a tsunami sediment transport model that can accurately estimate grain size distribution of tsunami deposit. Here, we built and validate a tsunami sediment transport model that can simulate grain size distribution. Our numerical model has three layers which are suspended load layer, active bed layer, and parent bed layer. The two bed layers contain information about the grain size distribution. This numerical model can handle a wide range of grain sizes from 0.063 (4 ϕ) to 5.657 mm (-2.5 ϕ). We apply the numerical model to simulate the sedimentation process during the 2011 Tohoku earthquake in Numanohama, Iwate prefecture, Japan. The grain size distributions at 15 sample points along a 900 m transect from the beach are used to validate the tsunami sediment transport model. The tsunami deposits are dominated by coarse sand with diameter of 0.5 - 1 mm and their thickness are up to 25 cm. Our tsunami model can well reproduce the observed tsunami run-ups that are ranged from 16 to 34 m along the steep valley in Numanohama. The shapes of the simulated grain size distributions at many sample points located within 300 m from the shoreline are similar to the observations. The differences between observed and simulated peak of grain size distributions are less than 1 ϕ. Our result also shows that the simulated sand thickness distribution along the transect is consistent with the observation.

Sulfur Biogeochemistry of an Oil Sands Composite Tailings Deposit

PubMed Central

Warren, Lesley A.; Kendra, Kathryn E.; Brady, Allyson L.; Slater, Greg F.

2016-01-01

Composite tailings (CT), an engineered, alkaline, saline mixture of oil sands tailings (FFT), processed sand and gypsum (CaSO4; 1 kg CaSO4 per m3 FFT) are used as a dry reclamation strategy in the Alberta Oil Sands Region (AOSR). It is estimated that 9.6 × 108 m3 of CT are either in, or awaiting emplacement in surface pits within the AOSR, highlighting their potential global importance in sulfur cycling. Here, in the first CT sulfur biogeochemistry investigation, integrated geochemical, pyrosequencing and lipid analyses identified high aqueous concentrations of ∑H2S (>300 μM) and highly altered sulfur compounds composition; low cell biomass (3.3 × 106– 6.0 × 106 cells g−1) and modest bacterial diversity (H' range between 1.4 and 1.9) across 5 depths spanning 34 m of an in situ CT deposit. Pyrosequence results identified a total of 29,719 bacterial 16S rRNA gene sequences, representing 131 OTUs spanning19 phyla including 7 candidate divisions, not reported in oil sands tailings pond studies to date. Legacy FFT common phyla, notably, gamma and beta Proteobacteria, Firmicutes, Actinobacteria, and Chloroflexi were represented. However, overall CT microbial diversity and PLFA values were low relative to other contexts. The identified known sulfate/sulfur reducing bacteria constituted at most 2% of the abundance; however, over 90% of the 131 OTUs identified are capable of sulfur metabolism. While PCR biases caution against overinterpretation of pyrosequence surveys, bacterial sequence results identified here, align with phospholipid fatty acid (PLFA) and geochemical results. The highest bacterial diversities were associated with the depth of highest porewater [∑H2S] (22–24 m) and joint porewater co-occurrence of Fe2+ and ∑H2S (6–8 m). Three distinct bacterial community structure depths corresponded to CT porewater regions of (1) shallow evident Fe(II) (<6 m), (2) co-occurring Fe(II) and ∑H2S (6–8 m) and (3) extensive ∑H2S (6–34 m) (Uni

Process for hydrogenation of hydrocarbon tars

DOEpatents

Dolbear, Geoffrey E.

1978-07-18

Hydrocarbon tars of high asphaltene content such as tars obtained from pyrolysis of coal are dissolved in a solvent formed from the hydrogenation of the coal tars, and the resultant mixture hydrogenated in the presence of a catalyst at a pressure from about 1500 to 5000 psig at a temperature from about 500.degree. F to about the critical temperature of the solvent to form a light hydrocarbon as a solvent for the tars. Hydrogen content is at least three times the amount of hydrogen consumed.

Monitoring Sand Sheets and Dunes

NASA Image and Video Library

2017-06-12

NASA's Mars Reconnaissance Orbiter (MRO) captured this crater featuring sand dunes and sand sheets on its floor. What are sand sheets? Snow fall on Earth is a good example of sand sheets: when it snows, the ground gets blanketed with up to a few meters of snow. The snow mantles the ground and "mimics" the underlying topography. Sand sheets likewise mantle the ground as a relatively thin deposit. This kind of environment has been monitored by HiRISE since 2007 to look for movement in the ripples covering the dunes and sheets. This is how scientists who study wind-blown sand can track the amount of sand moving through the area and possibly where the sand came from. Using the present environment is crucial to understanding the past: sand dunes, sheets, and ripples sometimes become preserved as sandstone and contain clues as to how they were deposited The map is projected here at a scale of 25 centimeters (9.8 inches) per pixel. [The original image scale is 25 centimeters (9.8 inches) per pixel (with 1 x 1 binning); objects on the order of 75 centimeters (29.5 inches) across are resolved.] North is up. https://photojournal.jpl.nasa.gov/catalog/PIA21757

Inland aeolian deposits of the Iberian Peninsula: Sand dunes and clay dunes of the Duero Basin and the Manchega Plain. Palaeoclimatic considerations

NASA Astrophysics Data System (ADS)

Bernat Rebollal, M.; Pérez-González, A.

2008-12-01

This paper describes the latest research on the geomorphological characteristics, formation environment and chronology of the main inland aeolian deposits from the south-eastern Duero Basin (DB) and the Manchega Plain (MP) of the Iberian Peninsula. Similarities and differences between the aeolian deposits of these two locations are summarised. Wind deflation from the Guadiana and Júcar alluvial systems created the aeolian deposits of the MP. These deposits are mainly composed of quartz sands. However, in the San Juan alluvial plain (MP) there is a large extent of clay dunes formed by exposure to prevalent winds of seasonal playa-lakes with salt and clay sediments. In the DB, wind remobilisation of the small particles from Quaternary terraces and Tertiary arkosic sediments left aeolian deposits of quartz-feldspar sands. Textural parameters of the aeolian deposits show large variations depending on the location and the original deposit. Thus, in the DB the aeolian sands derived from the deflation of fluvial sediments are better sorted and smaller in grain size than those created by the deflation of arkosic sediments. Morphologically, simple and compound parabolic dunes (U-V forms, hemicyclic, lobate and elongate), crescentic and linear dunes, climbing dunes and blowout dunes have been recognized at both sites. Barchan and dome dunes are present only in the DB while "lunette lunette-clay dunes" are found only in the MP. In both locations, the large extent of aeolian sand sheets and the predominance of simple and compound parabolic dunes indicates the active role of sparse vegetation cover in the formation of this aeolian system. In the DB, dunes were formed by southwest and west winds, while in the MP the aeolian morphologies indicate that the prevalent winds were west and northwest. The chronology of the dune deposits is being determined with luminescence (TL-OSL) dating and Mass Spectrometry Analysis ( 14C-AMS). In this way, the aeolian activity and stabilisation

Method for treatment of tar-bearing fuel gas

DOE Office of Scientific and Technical Information (OSTI.GOV)

Frauen, L.L.; Kasper, S.

1986-01-07

A process is described of producing a fuel gas which contains condensable tar vapor when it leaves a gasifier, the improvement wherein the tar-bearing gases are treated to remove tar therefrom. The process consists of: (a) continuously conducting hot fuel gas from a gasifier to and discharging it into a spray chamber where the hot tar-bearing gas is contacted with a fine spray of water thereby cooling the tar vapor and evaporating the water to produce a fog-like dispersion of tar in an atmosphere of fuel gas with the temperature in the spray chamber maintained above the dew point ofmore » water; (b) continuously transferring the fuel gas and the dispersion of tar and water to an electrostatic precipitator and precipitating therein at least most of the condensed tar as a liquid; (c) removing the liquid tar so precipitated and conducting at least most of it to a tar burner; (d) burning the tar with no more than the stoichiometric supply of oxygen provided by air to produce oxygen-free and tar-free hot combustion gases; (e) conducting the hot combustion gases directly into a mixer into which the fuel gas and water vapor flows from the precipitator, thereby adding to the fuel gas the sensible heat of the combustion gases; and (f) conducting the mixture so produced to a place of use as a hot fuel gas mixture.« less

A multi-isotope approach for assessing industrial contributions to atmospheric nitrogen deposition in the Athabasca oil sands region in Alberta, Canada

Treesearch

Bernadette C. Proemse; Bernhard Mayer; Mark E. Fenn; Christopher S. Ross

2013-01-01

Industrial nitrogen (N) emissions in the Athabasca oil sands region (AOSR), Alberta, Canada, affect nitrate (NO3) and ammonium (NH4) deposition rates in close vicinity of industrial emitters. NO3-N and NH4-N open field and throughfall deposition rates were determined at various...

Vertical ground motion and its effects on liquefaction resistance of fully saturated sand deposits

PubMed Central

Kontoe, Stavroula; Taborda, David M. G.; Potts, David M.

2016-01-01

Soil liquefaction has been extensively investigated over the years with the aim to understand its fundamental mechanism and successfully remediate it. Despite the multi-directional nature of earthquakes, the vertical seismic component is largely neglected, as it is traditionally considered to be of much lower amplitude than the components in the horizontal plane. The 2010–2011 Canterbury earthquake sequence in New Zealand is a prime example that vertical accelerations can be of significant magnitude, with peak amplitudes well exceeding their horizontal counterparts. As research on this topic is very limited, there is an emerging need for a more thorough investigation of the vertical motion and its effect on soil liquefaction. As such, throughout this study, uni- and bidirectional finite-element analyses are carried out focusing on the influence of the input vertical motion on sand liquefaction. The effects of the frequency content of the input motion, of the depth of the deposit and of the hydraulic regime, using variable permeability, are investigated and exhaustively discussed. The results indicate that the usual assumption of linear elastic response when compressional waves propagate in a fully saturated sand deposit does not always hold true. Most importantly post-liquefaction settlements appear to be increased when the vertical component is included in the analysis. PMID:27616931

Vertical ground motion and its effects on liquefaction resistance of fully saturated sand deposits.

PubMed

Tsaparli, Vasiliki; Kontoe, Stavroula; Taborda, David M G; Potts, David M

2016-08-01

Soil liquefaction has been extensively investigated over the years with the aim to understand its fundamental mechanism and successfully remediate it. Despite the multi-directional nature of earthquakes, the vertical seismic component is largely neglected, as it is traditionally considered to be of much lower amplitude than the components in the horizontal plane. The 2010-2011 Canterbury earthquake sequence in New Zealand is a prime example that vertical accelerations can be of significant magnitude, with peak amplitudes well exceeding their horizontal counterparts. As research on this topic is very limited, there is an emerging need for a more thorough investigation of the vertical motion and its effect on soil liquefaction. As such, throughout this study, uni- and bidirectional finite-element analyses are carried out focusing on the influence of the input vertical motion on sand liquefaction. The effects of the frequency content of the input motion, of the depth of the deposit and of the hydraulic regime, using variable permeability, are investigated and exhaustively discussed. The results indicate that the usual assumption of linear elastic response when compressional waves propagate in a fully saturated sand deposit does not always hold true. Most importantly post-liquefaction settlements appear to be increased when the vertical component is included in the analysis.

Mineral resource of the month: industrial sand and gravel

USGS Publications Warehouse

Dolley, Thomas

2007-01-01

With many diverse uses, industrial sand and gravel, also known as silica sand, is one of the most important nonmetallic minerals in the world. Industrial sand and gravel is a mining industry term used for sands that have a very high percentage of silicon dioxide, or greater than 95 percent quartz. Deposits of industrial sand and gravel can be found virtually everywhere on Earth, but are less widespread than deposits of common construction sand and gravel. Industrial sand and gravel is distinctive in grain size, hardness, inertness and resistance to high temperature and chemical action. Beverage containers, fiberglass insulation, fiber-optic cables and light bulbs are just some of today’s many products produced from industrial sand and gravel.

Heat-resistant agent used for control sand of steam huff and puff heavy oil well

NASA Astrophysics Data System (ADS)

Zhang, F. S.; Liu, G. L.; Lu, Y. J.; Xiong, X. C.; Ma, J. H.; Su, H. M.

2018-01-01

Heat-resistant agent containing hydroxymethyl group was synthesized from coal tar, which has similar structure with phenolic resin and could improve the heat resistance of phenolic resin sand control agent. The results showed that the heat resistance of the sand control agent was improved by adding 10% to 30% heat-resistant agent, after 280°C high temperature treatment for 7d, the compressive strength of consolidated core was increased to more than 5MPa. The compressive strength of consolidation core was not decreased after immersion in formation water, crude oil, acid or alkaline medium, which showed good resistance to medium immersion. The sand control agent had small core damage and the core permeability damage ratio of sand control agent consolidation was only 18.7%.

Which Came First?

NASA Image and Video Library

2015-09-16

The workings of the Martian winds are visible in this image of sand dunes trapped inside an unnamed crater in southern Terra Cimmeria captured by NASA Mars Reconnaissance Orbiter spacecraft. Many of the craters in the Southern highlands of Mars contain sand dunes, and HiRISE is still in the process of mapping these dunes and determining how active they are today. So far, the dunes in these craters appear to be a mixed bunch, with some dunes actively advancing while others seem to be frozen in place. This image will be compared to a previous picture, to see how these dunes have changed since 2008. The sand dunes are the large, branched ridges and dark patches that are conspicuous against the bright background, particularly in the northwest corner of our picture. There are also signs of two other wind-related processes: smaller, brighter ridges line the floor of the crater in regularly spaced rows. These are also windblown deposits, mysterious "transverse aeolian ridges" or TARs that are more common in the Martian tropics. Faint, irregular dark lines cross the dunes and the TARs, marking the tracks of dust devils that vacuum the surface during southern summer. So, which came first? We can untangle the history of these processes by looking at the picture more closely. Over most of the image, it is obvious that the dark sand dunes bury the bright TARs, meaning that the sand dunes are younger than the TARs. But this relationship is not so clear for the southernmost dune we see in this picture. Here, the TARs look like they extend into the dune and merge with ripples on the dune's surface, suggesting that the TARs might be younger than the dunes. The question can be resolved by carefully examining an enhanced color cutout. The TARs are brighter and redder than the sand dunes and this color persists on the crests of the TARs as the sand encroaches, burying the valleys first and then the slopes and finally the TAR crests. This tells us that the unusual appearance of the

43 CFR 3140.0-5 - Definitions.

Code of Federal Regulations, 2012 CFR

2012-10-01

... for the removal of gas and nongaseous hydrocarbon substances other than coal, oil shale or gilsonite... Existing Oil and Gas Leases and Valid Claims Based on Mineral Locations § 3140.0-5 Definitions. As used in... Sand Areas, as containing substantial deposits of tar sand. (d) Owner of an oil and gas lease means all...

43 CFR 3140.0-5 - Definitions.

Code of Federal Regulations, 2013 CFR

2013-10-01

... for the removal of gas and nongaseous hydrocarbon substances other than coal, oil shale or gilsonite... Existing Oil and Gas Leases and Valid Claims Based on Mineral Locations § 3140.0-5 Definitions. As used in... Sand Areas, as containing substantial deposits of tar sand. (d) Owner of an oil and gas lease means all...

43 CFR 3140.0-5 - Definitions.

Code of Federal Regulations, 2014 CFR

2014-10-01

... for the removal of gas and nongaseous hydrocarbon substances other than coal, oil shale or gilsonite... Existing Oil and Gas Leases and Valid Claims Based on Mineral Locations § 3140.0-5 Definitions. As used in... Sand Areas, as containing substantial deposits of tar sand. (d) Owner of an oil and gas lease means all...

43 CFR 3140.0-5 - Definitions.

Code of Federal Regulations, 2011 CFR

2011-10-01

... for the removal of gas and nongaseous hydrocarbon substances other than coal, oil shale or gilsonite... Existing Oil and Gas Leases and Valid Claims Based on Mineral Locations § 3140.0-5 Definitions. As used in... Sand Areas, as containing substantial deposits of tar sand. (d) Owner of an oil and gas lease means all...

A study of global sand seas

USGS Publications Warehouse

McKee, Edwin D.

1979-01-01

The birth of the idea that led to this publication on "Global Sand Seas" dates back to the late 1920's. At that time I was engaged in a study of the Coconino Sandstone of Arizona's Grand Canyon. Considerable controversy existed then as to whether this sandstone was a subaqueous deposit or was composed of wind-formed dunes. It became apparent that definitive literature was sparse or lacking on types of dunes, global distribution of these types, the mechanics of their development, the precise nature of their internal structure of cross-stratificiation, and the relation of wind systems to these sand forms. Especially lacking were data on criteria that could confidently be used in the recognition of ancient dunes. The common denominator in this publication is eolian sand bodies. Although the book is concerned primarily with desert sand seas, the subject matter is not restricted to deserts; it includes many references to deposits of coastal sand and to sand bodies in humid climates. Nor does the book deal exclusively with dunes, which, according to most definitions, involve mounds or hills. Many references are made to sand sheets, sand stringers, and other types of sand deposits that have no prominent topographic expression. All sand bodies accumulated by the action of wind are discussed. Chapters A-J of this publication are primarily topical. Chapters cover the grain texture, the color, and the structure of modern dunes and other eolian sands. Special treatment is given to the relation of wind data to dune interpretation, the evolution of form in current-deposited sand bodies as determined from experimental studies, and the discriminant analysis technique for differentiating between coastal and inland desert sands. This topical part of the publication also includes an analysis of criteria used in ancient deposits to interpret their eolian genesis and a consideration of economic application of the principles described, including a discussion of potentials and problems

Transport of colloidal silica in unsaturated sand: Effect of charging properties of sand and silica particles.

PubMed

Fujita, Yosuke; Kobayashi, Motoyoshi

2016-07-01

We have studied the transport of colloidal silica in various degrees of a water-saturated Toyoura sand column, because silica particles are widely used as catalyst carriers and abrasive agents, and their toxicity is reported recently. Since water-silica, water-sand, and air-water interfaces have pH-dependent negative charges, the magnitude of surface charge was controlled by changing the solution pH. The results show that, at high pH conditions (pH 7.4), the deposition of colloidal silica to the sand surface is interrupted and the silica concentration at the column outlet immediately reaches the input concentration in saturated conditions. In addition, the relative concentration of silica at the column outlet only slightly decreases to 0.9 with decreasing degrees of water saturation to 38%, because silica particles are trapped in straining regions in the soil pore and air-water interface. On the other hand, at pH 5 conditions (low pH), where sand and colloid have less charge, reduced repulsive forces result in colloidal silica attaching onto the sand in saturated conditions. The deposition amount of silica particles remarkably increases with decreasing degrees of water saturation to 37%, which is explained by more particles being retained in the sand column associated with the air-water interface. In conclusion, at higher pH, the mobility of silica particles is high, and the air-water interface is inactive for the deposition of silica. On the other hand, at low pH, the deposition amount increases with decreasing water saturation, and the particle transport is inhibited. Copyright © 2016 Elsevier Ltd. All rights reserved.

An Introduction to Using Surface Geophysics to Characterize Sand and Gravel Deposits

USGS Publications Warehouse

Lucius, Jeffrey E.; Langer, William H.; Ellefsen, Karl J.

2006-01-01

This report is an introduction to surface geophysical techniques that aggregate producers can use to characterize known deposits of sand and gravel. Five well-established and well-tested geophysical methods are presented: seismic refraction and reflection, resistivity, ground penetrating radar, time-domain electromagnetism, and frequency-domain electromagnetism. Depending on site conditions and the selected method(s), geophysical surveys can provide information concerning aerial extent and thickness of the deposit, thickness of overburden, depth to the water table, critical geologic contacts, and location and correlation of geologic features. In addition, geophysical surveys can be conducted prior to intensive drilling to help locate auger or drill holes, reduce the number of drill holes required, calculate stripping ratios to help manage mining costs, and provide continuity between sampling sites to upgrade the confidence of reserve calculations from probable reserves to proved reserves. Perhaps the greatest value of geophysics to aggregate producers may be the speed of data acquisition, reduced overall costs, and improved subsurface characterization.

An Introduction to Using Surface Geophysics to Characterize Sand and Gravel Deposits

USGS Publications Warehouse

Lucius, Jeffrey E.; Langer, William H.; Ellefsen, Karl J.

2007-01-01

This report is an introduction to surface geophysical techniques that aggregate producers can use to characterize known deposits of sand and gravel. Five well-established and well-tested geophysical methods are presented: seismic refraction and reflection, resistivity, ground penetrating radar, time-domain electromagnetism, and frequency-domain electromagnetism. Depending on site conditions and the selected method(s), geophysical surveys can provide information concerning areal extent and thickness of the deposit, thickness of overburden, depth to the water table, critical geologic contacts, and location and correlation of geologic features. In addition, geophysical surveys can be conducted prior to intensive drilling to help locate auger or drill holes, reduce the number of drill holes required, calculate stripping ratios to help manage mining costs, and provide continuity between sampling sites to upgrade the confidence of reserve calculations from probable reserves to proved reserves. Perhaps the greatest value of geophysics to aggregate producers may be the speed of data acquisition, reduced overall costs, and improved subsurface characterization.

Gravel and sand resources of the New England-New York region

USGS Publications Warehouse

Currier, Louis W.

1955-01-01

Deposits of sand and gravel are widespread in the New England-New York regions and constitute one of its principal mineral resources. Most of the pits are operated intermittently to supply local needs. Because of the great number and variety of known deposits, and because they have been worked at countless points it is impracticable to describe in detail either the deposits or the individual pits. On the other hand, a broad description of the geologic modes of occurrence with relation to the regional geology will serve adequately to indicate the importance of the resource in the regional economy and development. Except for some special sands, such as "glass sand", certain molding and foundry sands, et. al., for which restrictive textural, compositional and physical properties are required, sand and gravel are used chiefly for local construction and are not commonly transported for long distances. Sand and gravel deposits of the region fall into four principal genetic categories - e.g., glacial, alluvial, marine, and aeolian. Of these, deposits of glacial origin are by far the most widespread and important.

40 CFR 721.10532 - Tar, brown coal.

Code of Federal Regulations, 2014 CFR

2014-07-01

... 40 Protection of Environment 31 2014-07-01 2014-07-01 false Tar, brown coal. 721.10532 Section 721... Tar, brown coal. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified as tar, brown coal (PMN P-12-167, CAS No. 101316-83-0) is subject to...

40 CFR 721.10532 - Tar, brown coal.

Code of Federal Regulations, 2013 CFR

2013-07-01

... 40 Protection of Environment 32 2013-07-01 2013-07-01 false Tar, brown coal. 721.10532 Section 721... Tar, brown coal. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified as tar, brown coal (PMN P-12-167, CAS No. 101316-83-0) is subject to...

The Contribution of Oil Sands Industry Related Atmospheric THg and MeHg Deposition to Rivers of the Athabasca Oil Sands Region of Canada

NASA Astrophysics Data System (ADS)

Wasiuta, V. L.; Cooke, C. A.; Kirk, J.; Chambers, P. A.; Alexander, A. C.; Rooney, R. C.

2017-12-01

Rapid development of Oil Sands deposits in northern Alberta (Canada) raises concerns about human health and environmental impacts. We present results from a three-year study of winter-time atmospheric deposition of total mercury (THg) and methylmercury (MeHg) in six tributary watersheds of the Athabasca River. Seasonal snowpack THg and MeHg concentrations were obtained from spring-time sampling throughout the oil sands region. Winter-time Hg loads were then modeled at watershed and sub-basin scales using ArcGIS geostatistical kriging. To determine the potential impacts of snowmelt on aquatic ecosystems, six rivers were sampled at high frequency over 2012 to 2014 ice-free seasons. Hydrologic year (HY) and first discharge peak loads were then calculated from linear extrapolation of measured concentrations and mean daily discharge. Results showed high THg and MeHg loads from atmospheric deposition around regional upgrading facilities with loads diminishing outwards. This reflects the large proportion of particle bound Hg with a short atmospheric residence time, and deposition close to emission sources. Snowpacks within the six watersheds contained substantial proportions of tributary river THg and MeHg loads. For example, HY2014 snowpacks contained 24 to 46 % of river MeHg loads. All rivers showed a large proportion of HY loads discharged, within a few weeks, in the spring first discharge peak. HY2014 snowpack MeHg loads were greater than river loads in the first discharge peak for all watersheds except the High Hills. This first discharge peak is important as it occurs during critical growth periods for aquatic life. Large differences in tributary river THg and MeHg loads suggest factors other than atmospheric deposition and watershed scale contributed to the load. Considerably higher THg and MeHg snowpack loads in the Muskeg Watershed relative to river export suggest substantial losses to catchment soils or wetlands during snowmelt. Evaluation of factors that could

The impact of steam and current density on carbon formation from biomass gasification tar on Ni/YSZ, and Ni/CGO solid oxide fuel cell anodes

NASA Astrophysics Data System (ADS)

Mermelstein, Joshua; Millan, Marcos; Brandon, Nigel

The combination of solid oxide fuel cells (SOFCs) and biomass gasification has the potential to become an attractive technology for the production of clean renewable energy. However the impact of tars, formed during biomass gasification, on the performance and durability of SOFC anodes has not been well established experimentally. This paper reports an experimental study on the mitigation of carbon formation arising from the exposure of the commonly used Ni/YSZ (yttria stabilized zirconia) and Ni/CGO (gadolinium-doped ceria) SOFC anodes to biomass gasification tars. Carbon formation and cell degradation was reduced through means of steam reforming of the tar over the nickel anode, and partial oxidation of benzene model tar via the transport of oxygen ions to the anode while operating the fuel cell under load. Thermodynamic calculations suggest that a threshold current density of 365 mA cm -2 was required to suppress carbon formation in dry conditions, which was consistent with the results of experiments conducted in this study. The importance of both anode microstructure and composition towards carbon deposition was seen in the comparison of Ni/YSZ and Ni/CGO anodes exposed to the biomass gasification tar. Under steam concentrations greater than the thermodynamic threshold for carbon deposition, Ni/YSZ anodes still exhibited cell degradation, as shown by increased polarization resistances, and carbon formation was seen using SEM imaging. Ni/CGO anodes were found to be more resilient to carbon formation than Ni/YSZ anodes, and displayed increased performance after each subsequent exposure to tar, likely due to continued reforming of condensed tar on the anode.

Ripples and Dunes in Proctor Crater

NASA Image and Video Library

2017-10-09

NASA's Mars Reconnaissance Rover (MRO) has observed two types of wind (aeolian) features in Proctor Crater: large, dark features that are sand dunes, made up of basaltic particles, and smaller, light-toned ripples that we call "TAR," or "transverse aeolian ridges." The origin of the TARs is a mystery. They might be dust deposits, or perhaps coarse grained ripples that are coated in bright dust. These TARs are less than 10 meters tall, and are much smaller than the sand dunes that reach impressive heights of over 130 meters. In other places on Mars, TARs are generally older than sand dunes, but here in Proctor Crater, it is not so obvious. How can we tell which came first, the TARs or the dunes? The dunes are situated on top of the TARs, and with this information, we can say the dunes are clearly the younger formations here in Proctor Crater. Fortunately, HiRISE has a tool that can solve this riddle. By taking stereo images of the same region from two different locations, we can estimate the topography of the region by measuring the displacement of surface features from one picture to the other. The result is a quantitative estimate of the local surface topography, called a digital terrain model. The dunes are situated on top of the TARs, and with this information, we can say the dunes are clearly the younger formations here in Proctor Crater. https://photojournal.jpl.nasa.gov/catalog/PIA22040

Evaluating process origins of sand-dominated fluvial stratigraphy

NASA Astrophysics Data System (ADS)

Chamberlin, E.; Hajek, E. A.

2015-12-01

Sand-dominated fluvial stratigraphy is often interpreted as indicating times of relatively slow subsidence because of the assumption that fine sediment (silt and clay) is reworked or bypassed during periods of low accommodation. However, sand-dominated successions may instead represent proximal, coarse-grained reaches of paleo-river basins and/or fluvial systems with a sandy sediment supply. Differentiating between these cases is critical for accurately interpreting mass-extraction profiles, basin-subsidence rates, and paleo-river avulsion and migration behavior from ancient fluvial deposits. We explore the degree to which sand-rich accumulations reflect supply-driven progradation or accommodation-limited reworking, by re-evaluating the Castlegate Sandstone (Utah, USA) and the upper Williams Fork Formation (Colorado, USA) - two Upper Cretaceous sandy fluvial deposits previously interpreted as having formed during periods of relatively low accommodation. Both units comprise amalgamated channel and bar deposits with minor intra-channel and overbank mudstones. To constrain relative reworking, we quantify the preservation of bar deposits in each unit using detailed facies and channel-deposit mapping, and compare bar-deposit preservation to expected preservation statistics generated with object-based models spanning a range of boundary conditions. To estimate the grain-size distribution of paleo-sediment input, we leverage results of experimental work that shows both bed-material deposits and accumulations on the downstream side of bars ("interbar fines") sample suspended and wash loads of active flows. We measure grain-size distributions of bar deposits and interbar fines to reconstruct the relative sandiness of paleo-sediment supplies for both systems. By using these novel approaches to test whether sand-rich fluvial deposits reflect river systems with accommodation-limited reworking and/or particularly sand-rich sediment loads, we can gain insight into large

Investigations on Local Quartz Sand for Application in Glass Industry

NASA Astrophysics Data System (ADS)

Dararutana, Pisutti; Chetanachan, Prukswan; Wathanakul, Pornsawat; Sirikulrat, Narin

2009-03-01

Silica or glass sand is a special type of quartz sand that is suitable for glass-making, because of its high silica content, and its low content of iron oxide and other compounds. In Thailand, deposits of quartz sand are found as the beach and the river sands in many areas; eastern, southern, northeastern and northern. In this work, grain-size distribution and chemical analyses were carried out on 10 sand samples taken from various localities in Thailand such as Chanthaburi, Trat, Rayong, Chumphon, Nakhon Si, Pattani, Phuket, Songkhla, Nong Khai, and Tak provinces. The geological resources show that most of them are the surface-to-near-surface glass sand deposits. The sand grains in most deposits were mainly angular-to-rounded, except in some areas of either angular or rounded grains. Chemical analysis showed that the sands contained more than 95wt% silica and low content of Fe, Al, Ca, Mg, Na, and K. The concentration levels of these components in the samples confirm with internationally acceptable standard for glass production. The quartz sand dressing plants that used the spiral classifier to improve the properties of the quartz sands to meet the standard specifications are mostly located in the eastern area. It can be concluded that most of the quartz sand deposits in Thailand investigated show well-sorted grain-size with considerable purity, i.e. high-grade quality. The advanced works resulted in that these raw quartz sands can be used as raw material for fabrication of soda-lime, lead crystal, and lead-free high refractive index glasses. The colorless and various colored glass products have been satisfactorily used in the domestic art and glass manufactures.

Altitude of the top of the Sparta Sand and Memphis Sand in three areas of Arkansas

USGS Publications Warehouse

Pugh, Aaron L.; Westerfield, Paul W.; Gonthier, Gerard; Poynter, David T.

1998-01-01

The Sparta Sand and Memphis Sand form the second most productive aquifer in Arkansas. The Sparta Sand and Memphis Sand range in thick- ness from 0 to 900 feet, consisting of fine- to medium-grained sands interbedded with layers of silt, clay, shale, and minor amounts of lignite. Within the three areas of interest, the top surface of the Sparta Sand and Memphis Sand dips regionally east and southeast towards the axis of the Mississippi Embayment syncline and Desha Basin. Local variations in the top surface may be attributed to a combination of continued development of structural features, differential compaction, localized faulting, and erosion of the surface prior to subsequent inundation and deposition of younger sediments.

Geologic and paleoecologic studies of the Nebraska Sand Hills

USGS Publications Warehouse

Ahlbrandt, Thomas S.; Fryberger, S.G.; Hanley, John H.; Bradbury, J. Platt

1980-01-01

PART A: The Nebraska Sand Hills are an inactive, late Quaternary, most probably Holocene, dune field (covering 57,000 km 2 ) that have been eroded along streams and in blowouts, resulting in excellent lateral and vertical exposures of the stratification of dune and interdune sediments. This paper presents new data on the geometry, primary sedimentary structures, modification of sedimentary structures, direction of sand movement, and petrography of these eolian deposits. Eolian deposits of the Sand Hills occur as relatively thin (9-24 m) 'blanket' sands, composed of a complex of dune and discontinuous, diachronous interdune deposits unconformably overlying fluviolacustrine sediments. The internal stratification of large dunes in the Sand Hills (as high as 100 m), is similar to the internal stratification of smaller dunes of the same type in the Sand Hills, differing only in scale. Studies of laminae orientation in the Sand Hills indicate that transverse, barchan, and blowout dunes can be differentiated in rocks of eolian origin using both the mean dip angle of laminae and the mean angular deviation of dip direction. A variety of secondary structures modify or replace primary eolian stratification in the Sand Hills, the more common of which are dissipation structures and bioturbation. Dissipation structures in the Sand Hills may develop when infiltrating water deposits clay adjacent to less permeable layers in the sand, or along the upper margins of frozen layers that form in the sands during winter. Cross-bed measurements from dunes of the Nebraska Sand Hills necessitate a new interpretation of the past sand transport directions. The data from these measurements indicate a general northwest-to-southeast drift of sand, with a more southerly drift in the southeast part of the Sand Hills. A large area of small dunes < 100 m high) described by Smith (1965) as linear or seif in the central part of the Sand Hills was interpreted by him on the basis of morphology only. We

Tar Management and Recycling in Biomass Gasification and Syngas Purification

NASA Astrophysics Data System (ADS)

McCaffrey, Zach

Removal of tars is critical to the design and operation of biomass gasification systems as most syngas utilization processing equipment (e.g. internal combustion engines, gas turbines, fuel cells, and liquid fuel synthesis reactors) have a low tolerance for tar. Capturing and disposal of tar is expensive due to equipment costs, high hazardous waste disposal costs where direct uses cannot be found, and system energy losses incurred. Water scrubbing is an existing technique commonly used in gasification plants to remove contaminants and tar; however using water as the absorbent is non-ideal as tar compounds have low or no water solubility. Hydrophobic solvents can improve scrubber performance and this study evaluated tar solubility in selected solvents using slip-streams of untreated syngas from a laboratory fluidized bed reactor operated on almond composite feedstock using both air and steam gasification. Tar solubility was compared with Hansen's solubility theory to examine the extent to which the tar removal can be predicted. As collection of tar without utilization leads to a hazardous waste problem, the study investigated the effects of recycling tars back into the gasifier for destruction. Prior to experiments conducted on tar capture and recycle, characterizations of the air and steam gasification of the almond composite mix were made. This work aims to provide a better understanding of tar collection and solvent selection for wet scrubbers, and to provide information for designing improved tar management systems for biomass gasification.

Constraints on Paleotsunami Runup Derived from Sand Deposits Mantling Three Holocene Marine Terraces at Puatai Beach, Northern Hikurangi Subduction Margin, New Zealand

NASA Astrophysics Data System (ADS)

Clark, K.; Litchfield, N. J.; Cochran, U. A.; Berryman, K. R.; Power, W. L.; Steele, R.

2016-12-01

At Puatai Beach, Gisborne, New Zealand, a 90-m-long continuous trench was excavated across a sequence of three marine terraces. The trench exposed the stratigraphy of deposits mantling the stepped shore platforms. The sequence of shelly sand and gravel beach deposits and silty colluvium allowed us to reconstruct the timing of earthquakes that uplifted the terraces, and place constraints on the age, runup and inundation distances of tsunamis that impacted the coastline in the late Holocene. Radiocarbon ages from shelly beach deposits lying on the platforms were used to date the terrace uplift ages at 1920-1650 (upper), 1270-1030 (middle), and 520-320 (lower) cal. yr BP respectively; we interpret these ages as the timing of large (M7+) paleoearthquakes on the nearshore Gable End Fault. With the inner edge of the highest shore platform reaching 9 m elevation, this flight of terraces has an average uplift rate of 5.6 ± 1 mm/yr, the highest uplift rate along the Hikurangi margin. The silty colluvium layers overlying the beach deposits contain thin semi-continuous sand layers. Based on chronological, geomorphological, sedimentological and biological considerations we suggest that at least some of these sand layers are tsunami deposits. Three sand layers were dated at 1190-930, 400-100, and 450-150 cal. yr BP, and the chronological overlap of the latter two suggests they could be the same event. Estimates of tsunami run-up were obtained from the surveyed maximum heights, and allowing for terrace uplift, they were 9.3 ± 0.5 m, 12.6 ± 0.5 m and 4.2-1.2 ± 0.5 m amsl, for the two dated and one un-dated paleotsunamis respectively; inundation distances were 58 m, 61 m, and 23 m. The inferred tsunami ages are slightly younger than the time of uplift of the marine terraces, and this, as well as their stratigraphic position within colluvium, suggests they were not necessarily triggered by rupture of the Gable End Fault. The younger ages potentially overlap tsunami deposits

16 CFR 802.3 - Acquisitions of carbon-based mineral reserves.

Code of Federal Regulations, 2014 CFR

2014-01-01

... gas, shale or tar sands, or rights to reserves of oil, natural gas, shale or tar sands together with... gas, shale or tar sands, or rights to reserves of oil, natural gas, shale or tar sands and associated... pipeline and pipeline system or processing facility which transports or processes oil and gas after it...

16 CFR 802.3 - Acquisitions of carbon-based mineral reserves.

Code of Federal Regulations, 2010 CFR

2010-01-01

... gas, shale or tar sands, or rights to reserves of oil, natural gas, shale or tar sands together with... gas, shale or tar sands, or rights to reserves of oil, natural gas, shale or tar sands and associated... pipeline and pipeline system or processing facility which transports or processes oil and gas after it...

16 CFR 802.3 - Acquisitions of carbon-based mineral reserves.

Code of Federal Regulations, 2013 CFR

2013-01-01

... gas, shale or tar sands, or rights to reserves of oil, natural gas, shale or tar sands together with... gas, shale or tar sands, or rights to reserves of oil, natural gas, shale or tar sands and associated... pipeline and pipeline system or processing facility which transports or processes oil and gas after it...

16 CFR 802.3 - Acquisitions of carbon-based mineral reserves.

Code of Federal Regulations, 2012 CFR

2012-01-01

... gas, shale or tar sands, or rights to reserves of oil, natural gas, shale or tar sands together with... gas, shale or tar sands, or rights to reserves of oil, natural gas, shale or tar sands and associated... pipeline and pipeline system or processing facility which transports or processes oil and gas after it...

16 CFR 802.3 - Acquisitions of carbon-based mineral reserves.

Code of Federal Regulations, 2011 CFR

2011-01-01

... gas, shale or tar sands, or rights to reserves of oil, natural gas, shale or tar sands together with... gas, shale or tar sands, or rights to reserves of oil, natural gas, shale or tar sands and associated... pipeline and pipeline system or processing facility which transports or processes oil and gas after it...

Primary sedimentary structures and the internal architecture of a Martian sand body in search of evidence for sand transport and deposition

NASA Technical Reports Server (NTRS)

Basu, Abhijit

1988-01-01

Lunar experiences show that unmanned sample return missions, despite limitations on sample size, can produce invaluable data to infer crustal processes, regolith processes, regolith-atmosphere/ionosphere interaction processes, etc. Drill cores provide a record of regolith evolution as well as a more complete sample of the regolith than small scoops and/or rakes. It is proposed that: (1) a hole be drilled in a sand body to obtain continuous oriented cores; a depth of about 10 m would be compatible with what we know of bed form hierarchy of terrestrial stream deposits; (2) two trenches, at right angles to each other and close to the drill-hole, be dug and the walls scraped lightly such that primary/internal sedimentary structures of the sand body become visible; (3) the walls of the trenches be made gravitationally stable by impregnation techniques; (4) acetate or other peels of a strip on each wall be taken; and (5) appropriately scaled photographs of the walls be taken at different sun-angles to ensure maximum ease of interpretation of sedimentary structures; and, to correlate these structural features with those in the core at different depth levels of the core.

Final safety assessment of Coal Tar as used in cosmetics.

PubMed

2008-01-01

Coal Tar is a semisolid by-product obtained in the destructive distillation of bituminous coal, which functions in cosmetic products as a cosmetic biocide and denaturant--antidandruff agent is also listed as a function, but this is considered an over-the-counter (OTC) drug use. Coal Tar is a nearly black, viscous liquid, heavier than water, with a naphthalene-like odor and a sharp burning taste, produced in cooking ovens as a by-product in the manufacture of coke. Crude Coal Tar is composed of 48% hydrocarbons, 42% carbon, and 10% water. In 2002, Coal Tar was reported to the Food and Drug Administration (FDA) to be used in four formulations, all of which appear to be OTC drug products. Coal Tar is monographed by the FDA as Category I (safe and effective) OTC drug ingredient for use in the treatment of dandruff, seborrhoea, and psoriasis. Coal Tar is absorbed through the skin of animals and humans and is systemically distributed. In short-term studies, mice fed a diet containing Coal Tar found it unpalatable, but no adverse effects were reported other than weight loss; rats injected with Coal Tar experienced malaise in one study and decreased water intake and increased liver weights in another; rabbits injected with Coal Tar residue experienced eating avoidance, respiratory difficulty, sneezing, and weight loss. In a subchronic neurotoxicity study using mice, a mixture of phenols, cresols, and xylenols at concentrations approximately equal to those expected in Coal Tar extracts produced regionally selective effects, with a rank order of corpus striatum > cerebellum > cerebral cortex. Coal Tar applied to the backs of guinea pigs increases epidermal thickness. Painting female rabbits with tar decreases the absolute and relative weights of the ovaries and decreased the number of interstitial cells in the ovary. Four therapeutic Coal Tar preparations used in the treatment of psoriasis were mutagenic in the Ames assay. Urine and blood from patients treated with Coal Tar

Smokers' knowledge and understanding of advertised tar numbers: health policy implications.

PubMed

Cohen, J B

1996-01-01

This article examines health policy implications of providing smokers with numerical tar yield information in cigarette advertising. Results of a national probability telephone survey regarding smokers' knowledge and understanding of numerical tar yields and deliveries are reported. Few smokers knew the tar level of their own cigarettes (the exception being smokers of 1- to 5-mg tar cigarettes), and a majority could not correctly judge the relative tar levels of cigarettes. Smokers were unsure whether switching to lower-tar cigarettes would reduce their personal health risks. Many smokers relied on absolute numbers in making trade-offs between number of cigarettes smoked and their tar levels, thus confusion machine-rated tar-yields with actual amounts ingested. The wisdom of the present method of providing tar and nicotine numbers in ads and recommendations for modifying the test protocol are now under discussion. This research indicates that these tar numbers and their implications are poorly understood. The paper recommends revisions in tar ratings to make them more useful and a required statement on cigarette packages to more explicitly relate tar levels to major health risks.

The temporal relationship between advertising and sales of low-tar cigarettes.

PubMed

Reed, Mark B; Anderson, Christy M; Burns, David M

2006-12-01

To determine whether a temporal relationship exists between the advertising and sales of low-tar cigarettes. It was hypothesised that increases in the advertising of low-tar cigarettes would precede increases in sales for these cigarettes. The themes of cigarette advertisements were reviewed and coded for 20 low-tar cigarette brands advertised in 13 widely read magazines in the US between 1960 and 1996. These 20 brands represented most of the low-tar cigarette advertisements and cigarette sales from 1967 to 1996. Cigarette sales data were obtained from the 1994 Maxwell report that summarises all cigarette sales from 1925 to 1990. If the advertisement referred to the low-tar attributes of the cigarette advertised, the advertisement was coded as having a low-tar theme and was included in the analysis. Five different graphical presentations of the relationship between the advertising and sales of the 20 low-tar cigarette brands showed a temporal relationship between low-tar advertising and sales for these brands. This relationship was observed for brands that introduced a low-tar alternative into an existing brand family (eg, Marlboro Light) and for new exclusively low-tar brands (eg, Carlton). Despite large increases in the advertising for the exclusively low-tar brands, sales of these brands remained low relative to sales of the low-tar alternative brands. Increases in print advertising of 20 of the most popular low-tar cigarette brands were followed by increases in sales for these cigarettes. Despite increases in the advertising of exclusively low-tar brands in the mid-1970s and early 1980s, the sales of these brands never matched the sales of the low-tar alternative brands. This suggests that it may have been easier to get smokers to switch to low-tar brands within a brand family compared with entirely new low-tar brands. Over the past 30 years, the marketing of low-tar cigarettes as a healthier alternative to higher-tar cigarettes has resulted in these brands

7 CFR 3201.76 - Asphalt and tar removers.

Code of Federal Regulations, 2014 CFR

2014-01-01

... 7 Agriculture 15 2014-01-01 2014-01-01 false Asphalt and tar removers. 3201.76 Section 3201.76... Designated Items § 3201.76 Asphalt and tar removers. (a) Definition. Cleaning agents designed to remove asphalt or tar from equipment, roads, or other surfaces. (b) Minimum biobased content. The Federal...

7 CFR 3201.76 - Asphalt and tar removers.

Code of Federal Regulations, 2013 CFR

2013-01-01

... 7 Agriculture 15 2013-01-01 2013-01-01 false Asphalt and tar removers. 3201.76 Section 3201.76... Designated Items § 3201.76 Asphalt and tar removers. (a) Definition. Cleaning agents designed to remove asphalt or tar from equipment, roads, or other surfaces. (b) Minimum biobased content. The Federal...

Becquerel Crater Deposit

NASA Technical Reports Server (NTRS)

2002-01-01

(Released 28 May 2002) The finely layered deposit in Becquerel crater, seen in the center of this THEMIS image, is slowly being eroded away by the action of windblown sand. Dark sand from a source north of the bright deposit is collecting along its northern edge, forming impressive barchan style dunes. These vaguely boomerang-shaped dunes form with their two points extending in the downwind direction, demonstrating that the winds capable of moving sand grains come from the north. Grains that leave the dunes climb the eroding stair-stepped layers, collecting along the cliff faces before reaching the crest of the deposit. Once there, the sand grains are unimpeded and continue down the south side of the deposit without any significant accumulation until they fall off the steep cliffs of the southern margin. The boat-hull shaped mounds and ridges of bright material called yardangs form in response to the scouring action of the migrating sand. To the west, the deposit has thinned enough that the barchan dunes extend well into the deeply eroded north-south trending canyons. Sand that reaches the south side collects and reforms barchan dunes with the same orientation as those on the north side of the deposit. Note the abrupt transition between the bright material and the dark crater floor on the southern margin. Steep cliffs are present with no indication of rubble from the obvious erosion that produced them. The lack of debris at the base of the cliffs is evidence that the bright material is readily broken up into particles that can be transported away by the wind. The geological processes that are destroying the Becquerel crater deposit appear active today. But it is also possible that they are dormant, awaiting a particular set of climatic conditions that produces the right winds and perhaps even temperatures to allow the erosion to continue.

Smokers' knowledge and understanding of advertised tar numbers: health policy implications.

PubMed Central

Cohen, J B

1996-01-01

OBJECTIVES. This article examines health policy implications of providing smokers with numerical tar yield information in cigarette advertising. METHODS. Results of a national probability telephone survey regarding smokers' knowledge and understanding of numerical tar yields and deliveries are reported. RESULTS. Few smokers knew the tar level of their own cigarettes (the exception being smokers of 1- to 5-mg tar cigarettes), and a majority could not correctly judge the relative tar levels of cigarettes. Smokers were unsure whether switching to lower-tar cigarettes would reduce their personal health risks. Many smokers relied on absolute numbers in making trade-offs between number of cigarettes smoked and their tar levels, thus confusion machine-rated tar-yields with actual amounts ingested. CONCLUSIONS. The wisdom of the present method of providing tar and nicotine numbers in ads and recommendations for modifying the test protocol are now under discussion. This research indicates that these tar numbers and their implications are poorly understood. The paper recommends revisions in tar ratings to make them more useful and a required statement on cigarette packages to more explicitly relate tar levels to major health risks. PMID:8561236

The Australian tar derby: the origins and fate of a low tar harm reduction programme

PubMed Central

King, W; Carter, S; Borland, R; Chapman, S; Gray, N

2003-01-01

Objective: To document the development of the low tar harm reduction programme in Australia, including tobacco industry responses. Data sources: Tobacco industry documents, retail tobacco journals, newspapers, medical journals, and Anti-Cancer Council of Victoria (ACCV) newsletters and archival records. Study selection: Documents on the strategies and knowledge bases of the ACCV, other Australian health authorities, and the tobacco industry. Results: The ACCV built a durable system for measuring and publicising the tar and nicotine yields of Australian cigarettes and influencing their development. The tobacco industry initially sought to block the development of this system but later appeared to cooperate with it, as is evidenced by the current market dominance of low tar brands. However, behind the scenes, the industry used its substantial knowledge advantage regarding compensatory smoking and its ability to re-engineer cigarettes to gain effective control of the system and subvert the ACCV's objectives. Conclusions: Replacement of the low tar programme with new means of minimising the harms from cigarette smoking should be a policy priority for the Australian government. This will require regulation, rather than further voluntary agreements, and stringent monitoring of successor programmes will be necessary. PMID:14645950

Sand pulses and sand patches on the Colorado River in Grand Canyon

USGS Publications Warehouse

Grams, Paul E.; Buscombe, Daniel; Topping, David; Mueller, Erich R.

2017-01-01

Alluvial sandbars occur in lateral recirculation zones (eddies) along the Colorado River in Grand Canyon National Park (Schmidt, 1990). Resource managers periodically release controlled floods from the upstream Glen Canyon Dam to rebuild these bars (Grams et al., 2015), which erode during fluctuating dam releases, and by hillslope runoff and wind deflation (Hazel et al., 2010). Because the dam blocks upstream sediment, episodic floods from tributaries provide the only supply to replace eroded sand; and much of this sand originates from a single tributary (Topping et al., 2000). Here, we present new evidence for the downstream translation of the sand component of these sediment inputs as discontinuous sand pulses. Improved understanding of the behaviour of these sand pulses may be used to adjust the timing, magnitude, and duration of controlled floods to maximize potential for deposition on sandbars in different segments of the 450 km-long Grand Canyon.

Numerical simulation of wind-sand movement in the reversed flow region of a sand dune with a bridge built downstream.

PubMed

He, Wei; Huang, Ning; Xu, Bin; Wang, Wenbo

2018-04-23

A bridge built inside the reversed flow region of a sand dune will change the characteristics of wind-sand movement in this region. The Reynolds-averaged Navier-Stokes simulation and discrete particle tracing are used to simulate the wind-sand movement around a sand dune with a bridge built inside the reversed region. Three cases with different bridge positions are studied. The results show that 1) compared with the isolated dune case, a tall bridge built at the leeward toe leads to an increase in the deposition rate on the leeward slope and a longer reversed flow region downstream of the sand dune; meanwhile, the high speed of crosswind on the bridge indicates that some measures should be taken to protect trains from strong crosswind; 2) a low bridge at the leeward toe has little effect on the sand deposition and reversed flow region of the dune; however, low sand transport rate and crosswind speed on the bridge show that anti-crosswind/sand measures should be taken according to the actual situation and 3) a low bridge on the leeward slope has little effect on the length of reversed flow region, however, high crosswind speed and sand flux on the bridge reveal the need of anti-crosswind/sand measures on the bridge. Moreover, the bridges in the reversed flow region increase the sand flux near the leeward crest; as a result, the moving patterns of the sand dune are changed.

The temporal relationship between advertising and sales of low‐tar cigarettes

PubMed Central

Reed, Mark B; Anderson, Christy M; Burns, David M

2006-01-01

Objective and hypothesis To determine whether a temporal relationship exists between the advertising and sales of low‐tar cigarettes. It was hypothesised that increases in the advertising of low‐tar cigarettes would precede increases in sales for these cigarettes. Methods The themes of cigarette advertisements were reviewed and coded for 20 low‐tar cigarette brands advertised in 13 widely read magazines in the US between 1960 and 1996. These 20 brands represented most of the low‐tar cigarette advertisements and cigarette sales from 1967 to 1996. Cigarette sales data were obtained from the 1994 Maxwell report that summarises all cigarette sales from 1925 to 1990. If the advertisement referred to the low‐tar attributes of the cigarette advertised, the advertisement was coded as having a low‐tar theme and was included in the analysis. Results Five different graphical presentations of the relationship between the advertising and sales of the 20 low‐tar cigarette brands showed a temporal relationship between low‐tar advertising and sales for these brands. This relationship was observed for brands that introduced a low‐tar alternative into an existing brand family (eg, Marlboro Light) and for new exclusively low‐tar brands (eg, Carlton). Despite large increases in the advertising for the exclusively low‐tar brands, sales of these brands remained low relative to sales of the low‐tar alternative brands. Conclusions Increases in print advertising of 20 of the most popular low‐tar cigarette brands were followed by increases in sales for these cigarettes. Despite increases in the advertising of exclusively low‐tar brands in the mid‐1970s and early 1980s, the sales of these brands never matched the sales of the low‐tar alternative brands. This suggests that it may have been easier to get smokers to switch to low‐tar brands within a brand family compared with entirely new low‐tar brands. Over the past 30 years, the marketing of low‐tar

Insights from Askja sand sheet, Iceland, as a depositional analogue for the Bagnold Dune Field, Gale Crater, Mars.

NASA Astrophysics Data System (ADS)

Ukstins, I.; Sara, M.; Riishuus, M.; Schmidt, M. E.; Yingst, R. A.; Berger, J.

2017-12-01

Examining the compositional effect of aeolian transport and sorting processes on basaltic sands is significant for understanding the evolution of the Bagnold dune field, as well as other martian soils and sedimentary units. We use the Askja sand sheet, Iceland, as a testbed to quantify the nature of soil production and aeolian transport processes in a mafic system. Basalts from Askja and surrounding volcanic units, which can have high MgO (5-18 wt %) and high Fe2O3 (5-18 wt %), have been weathered to form mafic volcaniclastic deposits which are incorporated into a 40-km long sand sheet to the E-SE of the caldera, ranging from 10 cm to 10 m thick, and covering 240 km2. Ash and lava from the 2014-2015 Holuhraun eruption were emplaced onto the southeastern part of the sand sheet. The SW section is deflationary and defined by very fine to medium grained basaltic sand with ventifact cobbles and boulders. The central part is inflating and dominated by very fine-grained sand, relict lava fields, and small to large sand ripples (1 to 30 cm). The NE portion is also inflating but accumulation is limited to topographic depressions. Bulk chemistry of >200 sand samples are similar to Martian crust (SiO2: 48-52 wt %, MgO: 5-8 wt %, Fe2O3: 13-15 wt %). MgO concentrations vary with distance along the sand sheet, increasing by 1.5% over 10 km in the downwind direction (E, NE), then maintaining a relatively consistent concentration of 6.75 wt % over 18 km. Mean equancy of grains decreases 15 % to the E over 10 km followed by a plateau at 65 to 75 %. Material at depth tends to be of higher sphericity than material on or near the surface. Notably, MgO increases while the sphericity decreases and both data sets level off at 10 km, which suggests these two variables are related. These indicate input of material with prismoidal morphology around 10 km, and may be due to the Holuhraun eruption.

Plant Community and Nitrogen Deposition as Drivers of Alpha and Beta Diversities of Prokaryotes in Reconstructed Oil Sand Soils and Natural Boreal Forest Soils

PubMed Central

Prescott, Cindy E.; Renaut, Sébastien; Terrat, Yves; Grayston, Sue J.

2017-01-01

ABSTRACT The Athabasca oil sand deposit is one of the largest single oil deposits in the world. Following surface mining, companies are required to restore soil-like profiles that can support the previous land capabilities. The objective of this study was to assess whether the soil prokaryotic alpha diversity (α-diversity) and β-diversity in oil sand soils reconstructed 20 to 30 years previously and planted to one of three vegetation types (coniferous or deciduous trees and grassland) were similar to those found in natural boreal forest soils subject to wildfire disturbance. Prokaryotic α-diversity and β-diversity were assessed using massively parallel sequencing of 16S rRNA genes. The β-diversity, but not the α-diversity, differed between reconstructed and natural soils. Bacteria associated with an oligotrophic lifestyle were more abundant in natural forest soils, whereas bacteria associated with a copiotrophic lifestyle were more abundant in reconstructed soils. Ammonia-oxidizing archaea were most abundant in reconstructed soils planted with grasses. Plant species were the main factor influencing α-diversity in natural and in reconstructed soils. Nitrogen deposition, pH, and plant species were the main factors influencing the β-diversity of the prokaryotic communities in natural and reconstructed soils. The results highlight the importance of nitrogen deposition and aboveground-belowground relationships in shaping soil microbial communities in natural and reconstructed soils. IMPORTANCE Covering over 800 km2, land disturbed by the exploitation of the oil sands in Canada has to be restored. Here, we take advantage of the proximity between these reconstructed ecosystems and the boreal forest surrounding the oil sand mining area to study soil microbial community structure and processes in both natural and nonnatural environments. By identifying key characteristics shaping the structure of soil microbial communities, this study improved our understanding of

Sand effects on thermal barrier coatings for gas turbine engines

NASA Astrophysics Data System (ADS)

Walock, Michael; Barnett, Blake; Ghoshal, Anindya; Murugan, Muthuvel; Swab, Jeffrey; Pepi, Marc; Hopkins, David; Gazonas, George; Kerner, Kevin

Accumulation and infiltration of molten/ semi-molten sand and subsequent formation of calcia-magnesia-alumina-silicate (CMAS) deposits in gas turbine engines continues to be a significant problem for aviation assets. This complex problem is compounded by the large variations in the composition, size, and topology of natural sands, gas generator turbine temperatures, thermal barrier coating properties, and the incoming particulate's momentum. In order to simplify the materials testing process, significant time and resources have been spent in the development of synthetic sand mixtures. However, there is debate whether these mixtures accurately mimic the damage observed in field-returned engines. With this study, we provide a direct comparison of CMAS deposits from both natural and synthetic sands. Using spray deposition techniques, 7% yttria-stabilized zirconia coatings are deposited onto bond-coated, Ni-superalloy discs. Each sample is coated with a sand slurry, either natural or synthetic, and exposed to a high temperature flame for 1 hour. Test samples are characterized before and after flame exposure. In addition, the test samples will be compared to field-returned equipment. This research was sponsored by the US Army Research Laboratory, and was accomplished under Cooperative Agreement # W911NF-12-2-0019.

Coupled changes in sand grain size and sand transport driven by changes in the upstream supply of sand in the Colorado River: relative importance of changes in bed-sand grain size and bed-sand area

USGS Publications Warehouse

Topping, D.J.; Rubin, D.M.; Melis, T.S.

2007-01-01

Sand transport in the Colorado River in Marble and Grand canyons was naturally limited by the upstream supply of sand. Prior to the 1963 closure of Glen Canyon Dam, the river exhibited the following four effects of sand supply limitation: (1) hysteresis in sediment concentration, (2) hysteresis in sediment grain size coupled to the hysteresis in sediment concentration, (3) production of inversely graded flood deposits, and (4) development or modification of a lag between the time of a flood peak and the time of either maximum or minimum (depending on reach geometry) bed elevation. Construction and operation of the dam has enhanced the degree to which the first two of these four effects are evident, and has not affected the degree to which the last two effects of sand supply limitation are evident in the Colorado River in Marble and Grand canyons. The first three of the effects involve coupled changes in suspended-sand concentration and grain size that are controlled by changes in the upstream supply of sand. During tributary floods, sand on the bed of the Colorado River fines; this causes the suspended sand to fine and the suspended-sand concentration to increase, even when the discharge of water remains constant. Subsequently, the bed is winnowed of finer sand, the suspended sand coarsens, and the suspended-sand concentration decreases independently of discharge. Also associated with these changes in sand supply are changes in the fraction of the bed that is covered by sand. Thus, suspended-sand concentration in the Colorado River is likely regulated by both changes in the bed-sand grain size and changes in the bed-sand area. A physically based flow and suspended-sediment transport model is developed, tested, and applied to data from the Colorado River to evaluate the relative importance of changes in the bed-sand grain size and changes in the bed-sand area in regulating suspended-sand concentration. Although the model was developed using approximations for steady

First direct observation of the link between supercritical flow processes, crescent-shape bedforms and massive sand deposits

NASA Astrophysics Data System (ADS)

Hage, Sophie; Cartigny, Matthieu; Clare, Michael; Sumner, Esther; Talling, Peter; Vendettuoli, Daniela; Hughes Clarke, John; Hubbard, Stephen

2017-04-01

Massive sandstones have been studied in many outcrops worldwide as they form a building stone of good subsurface petroleum reservoirs. Massive sands are often associated with turbidites sequences in ancient sedimentary successions. Turbidites are widely known to result from the deceleration of turbidity currents, these underwater flows driven by the excess density of sediments they carry in suspension. Depositional processes that are associated with the formation of massive sands are still under debate in the literature and many theoretical mechanisms have been suggested based on outcrops interpretations, lab experiments and numerical models. Here we present the first field observations that show how massive sands are generated from flow instabilities associated with supercritical flow processes occurring in turbidity currents. We combine turbidity current measurements with seafloor topography observations on the active Squamish Delta, British Columbia (Canada). We show that supercritical flow processes shape crescent-shape bedforms on the seafloor, and how these crescent-shape bedforms are built by massive sands. This modern process-product link is then used to interpret massive sandstone successions found in ancient outcrops. We demonstrate that supercritical-flow processes can be recognised in outcrops and that these processes produce highly diachronous stratigraphic surfaces in the rock record. This has profound implications on how to interpret ancient geological successions and the Earth history they archive.

OSL age and stratigraphy of the Strauss sand sheet in New Mexico, USA

NASA Astrophysics Data System (ADS)

Hall, Stephen A.; Goble, Ronald J.

2015-07-01

The Strauss sand sheet occurs in south-central New Mexico, USA, and northern Chihuahua, Mexico, covering an area of about 4740 km2. Its chronology is determined by 19 OSL ages. The sand sheet formed primarily during three phases of eolian deflation and deposition, each phase with a separate sand source and under different climatic and environmental circumstances. The first phase of eolian sedimentation occurred 45 to 15 ka with the deposition of unit 1. The sand source for the first phase was beach-related features along the eastern shoreline of pluvial Lake Palomas in Mexico. The glacial-age climate was cool, wet, and windy because of the southern path of the jet stream at that time. After 15 ka, with the onset of warmer conditions of the Bølling-Allerød, the shutting down of the Palomas sand source, and wet conditions of the Younger Dryas, the sand sheet stabilized with weak soil development in unit 1. By 11 ka, the climate shifted to Holocene drying conditions and the second phase of sand accumulation began, forming unit 2; the sand source was the local deflation of the previously deposited unit 1 sand. The sand sheet stabilized again by 1.9 ka with slightly wetter late Holocene climate; a weak soil formed in unit 2 sand. About A.D. 1500 and extending to about A.D. 1850 or later, an A horizon formed on the sand sheet, probably in response to a desert grassland vegetation during the period of wet climate of the Little Ice Age. In an anthropogenic third phase of eolian activity, after A.D. 1850, the vegetation was likely disturbed by overgrazing; and the unit 2 and A horizon (unit 3) sands were deflated, resulting in the deposition of a thin layer of massive eolian sand (unit 4) across the sand sheet. By about A.D. 1900 mesquite shrubs had increased in abundance; and deflated sand, largely from unit 2, began to accumulate around the shrubs, forming coppice dunes (unit 5). Mesquite coppice dunes continued to increase in number and volume during the twentieth

Enriching acid rock drainage related microbial communities from surface-deposited oil sands tailings.

PubMed

Dean, Courtney; Xiao, Yeyuan; Roberts, Deborah J

2016-10-01

Little is known about the microbial communities native to surface-deposited pyritic oil sands tailings, an environment where acid rock drainage (ARD) could occur. The goal of this study was to enrich sulfur-oxidizing organisms from these tailings and determine whether different populations exist at pH levels 7, 4.5, and 2.5. Using growth-based methods provides model organisms for use in the future to predict potential activities and limitations of these organisms and to develop possible control methods. Thiosulfate-fed enrichment cultures were monitored for approximately 1 year. The results showed that the enrichments at pH 4.5 and 7 were established quicker than at pH 2.5. Different microbial community structures were found among the 3 pH environments. The sulfur-oxidizing microorganisms identified were most closely related to Halothiobacillus neapolitanus, Achromobacter spp., and Curtobacterium spp. While microorganisms related to Chitinophagaceae and Acidocella spp. were identified as the only possible iron-oxidizing and -reducing microbes. These results contribute to the general knowledge of the relatively understudied microbial communities that exist in pyritic oil sands tailings and indicate these communities may have a potential role in ARD generation, which may have implications for future tailings management.

Transverse Aeolian Ridges (TARs) on Mars II: Distributions, orientations, and ages

NASA Astrophysics Data System (ADS)

Berman, Daniel C.; Balme, Matthew R.; Rafkin, Scot C. R.; Zimbelman, James R.

2011-05-01

Transverse Aeolian Ridges (TARs), 10 m scale, ripple-like aeolian bedforms with simple morphology, are widespread on Mars but it is unknown what role they play in Mars' wider sediment cycle. We present the results of a survey of all Mars Global Surveyor Narrow angle images in a pole-to-pole study area, 45° longitude wide. Following on from the classification scheme and preliminary surveys of Balme et al. (Balme, M.R., Berman, D.C., Bourke, M.C., Zimbelman, J.R. [2008a]. Geomorphology 101, 703-720) and Wilson and Zimbelman (Wilson, S.A., Zimbelman, J.R. [2004]. J. Geophys. Res. 109 (E10). doi: 10.1029/2004JE002247) we searched more than 10,000 images, and found that over 2000 reveal at least 5% areal cover by TARs. The mean TAR areal cover in the study area is about 7% (3% in the northern hemisphere and 11% in the southern hemisphere) but TARs are not homogenously distributed - they are concentrated in the mid-low latitudes and almost absent poleward of 35°N and 55°S. We found no clear correlation between TAR distribution and any of thermal inertia, kilometer-scale roughness, or elevation. We did find that TARs are less common at extremes of elevation. We found that TARs are most common near the equator (especially in the vicinity of Meridiani Planum, in which area they have a distinctive "barchan-like" morphology) and in large southern-hemisphere impact craters. TARs in the equatorial band are usually associated with outcrops of layered terrain or steep slopes, hence their relative absence in the northern hemisphere. TARs in the southern hemisphere are most commonly associated with low albedo, intercrater dune fields. We speculate that the mid-latitude mantling terrain (e.g., Mustard, J.F., Cooper, C.D., Rifkin, M.K. [2001]. Nature 412, 411-414; Kreslavsky, M.A., Head, J.W. [2002]. J. Geophys. Res. 29 (15). doi: 10.1029/2002GL015392) could also play a role in covering TARs or inhibiting saltation. We compared TAR distribution with general circulation model (GCM

Sedimentary structures and textures of Rio Orinoco channel sands, Venezuela and Colombia

USGS Publications Warehouse

McKee, Edwin Dinwiddie

1989-01-01

Most sedimentary structures represented in sand bodies of the Rio Orinoco are tabular-planar cross-strata which, together with some wedge-planar cross-strata, are the products of sand-wave deposition. Locally, in areas of river meander where point bars characteristically form, trough structures forming festoon patterns are numerous. At a few localities, sets of nearly horizontal strata occur between tabular-planar sets and are interpreted to be the deposits of very fast currents of the upper flow regime; elsewhere, uncommon lenses and beds of silt, clay, or organic matter consisting of leaves and twigs, seem to be the result of quiet-water settling through gravity. By far the most common grain size represented in the tabular-planar and wedge-planar cross-strata of the sandwave deposits is medium sand (? - ? millimeter) as determined by screen analyses. Many samples, however, also contain moderate quantities of coarse or very coarse sand. Eolian dunes on top of the sand-wave deposits are dominantly fine grained. The river channel sands were determined to be largely moderately well sorted, although in some places they were mostly well sorted, and in others, mostly moderately sorted.

Spatial and temporal patterns in trace element deposition to lakes in the Athabasca oil sands region (Alberta, Canada)

NASA Astrophysics Data System (ADS)

Cooke, Colin A.; Kirk, Jane L.; Muir, Derek C. G.; Wiklund, Johan A.; Wang, Xiaowa; Gleason, Amber; Evans, Marlene S.

2017-12-01

The mining and processing of the Athabasca oil sands (Alberta, Canada) has been occurring for decades; however, a lack of consistent regional monitoring has obscured the long-term environmental impact. Here, we present sediment core results to reconstruct spatial and temporal patterns in trace element deposition to lakes in the Athabasca oil sands region. Early mining operations (during the 1970s and 1980s) led to elevated V and Pb inputs to lakes located <50 km from mining operations. Subsequent improvements to mining and upgrading technologies since the 1980s have reduced V and Pb loading to near background levels at many sites. In contrast, Hg deposition increased by a factor of ~3 to all 20 lakes over the 20th century, reflecting global-scale patterns in atmospheric Hg emissions. Base cation deposition (from fugitive dust emissions) has not measurably impacted regional lake sediments. Instead, results from a principal components analysis suggest that the presence of carbonate bedrock underlying lakes located close to development appears to exert a first-order control over lake sediment base cation concentrations and overall lake sediment geochemical composition. Trace element concentrations generally did not exceed Canadian sediment quality guidelines, and no spatial or temporal trends were observed in the frequency of guideline exceedence. Our results demonstrate that early mining efforts had an even greater impact on trace element cycling than has been appreciated previously, placing recent monitoring efforts in a critical long-term context.

Atmospheric tar balls from biomass burning in Mexico

NASA Astrophysics Data System (ADS)

Adachi, K.; Buseck, P. R.

2009-12-01

Tar balls are spherical, organic aerosol particles that result from biofuel or biomass burning. They absorb sunlight and cause warming of the atmosphere. Although distinctive when viewed with a transmission electron microscope (TEM) because of their spherical shape, much remains to be determined about details of their compositions, occurrences, and generation. Here we aim to characterize the occurrences of tar balls using individual-particle analyses with a TEM and to study their formation in young biomass-burning smoke. The samples were collected using the U.S. Forest Service Twin Otter aircraft during the MILAGRO (Megacity Initiative: Local and Global Research Observations) campaign conducted in March 2006. We analyzed 84 TEM grid samples from ~30 biomass-burning events near Mexico City and over Yucatan. Sixty samples were from young smoke (less than an hour old), and others were from haze that mainly occurred from biomass burning. Tar balls have neither an evident nucleus nor are they normally attached to other particles. They are almost perfectly spherical on TEM grids, indicating that they were solid when collected. It appears as if tar balls consist of lower volatility organic matter than many other organic aerosol particles. On average, 9% by number of biomass-burning aerosol particles were tar balls in samples collected between a few minutes to an hour after emission. On the other hand, samples collected within a few minutes after emission included few or no tar balls. The occurrences and abundances of atmospheric tar balls are important when evaluating the effects of smoke on local and regional climate.

Elevated Nitrogen Deposition from Alberta Oil Sands Development Stimulates Phosphatase Activity in Dominant Sphagnum Moss Species

NASA Astrophysics Data System (ADS)

Kashi, N. N.; Wieder, R.; Vile, M. A.

2013-12-01

Emissions of NOx associated with Alberta oil sands (AOS) development are leading to locally elevated atmospheric N deposition, in a region where background N deposition has been historically quite low (< 1 kg/ha/yr). This elevated N deposition has the potential to alter the ecosystem structure and function of nutrient-poor boreal peatlands. Nitrogen enrichment may alter soil microbial activity, which could be manifested in changes in extracellular enzyme activities. Since 2011, we have been experimentally adding N as NH4NO3 in simulated precipitation at 0, 5, 10, 15, 20, and 25 kg N ha/yr/ plus no-water controls to a boreal bog and a poor fen (3 replicate plots per treatment). In 2013, acid phosphatase activities in living plant capitulum of Sphagnum angustifolium, Sphagnum fuscum, and Sphagnum magellanicum were quantified in June and July using 4-methyumbelliferylphosphate and fluorescence detection of the enzymatically released methylumbelliferone (MUF). Phosphatase activities did not differ with N treatment for S. angustifolium in the bog (p=0.3409) or the poor fen (p=0.0629), or for S. fuscum in the bog (p=0.1950), averaging 35.0 × 0.7, 61.6 × 1.2, and 41.6 × 0.9 μmol MUF/g DWT/hr, respectively. For S. fuscum in the poor fen, phosphatase activities differed between N treatments (p=0.0275), ranging 40.6 × 1.1 μmol MUF/g DWT/hr in the control plots to 73.7 × 2.0 μmol MUF/g DWT/hr in the 5 kg/ha/yr N treatment plots; increasing N deposition did not result in a gradual change in enzyme activity. On the other hand, S. magellanicum phosphatase activities differed between N treatments (p=0.0189) and showed a pattern of generally increasing activity with increasing N deposition (37.4 × 0.5 μmol MUF/g DWT/hr in control plots; 97.9 × 4.5 μmol MUF/g DWT/hr in the 25 kg/ha/yr N treatment plots). The differing phosphatase responses between these dominant Sphagnum species suggest unique differences in nutrient balance and/or microbial activity. Combining the

Atmospheric Tar Balls: Particles from Biomass and Biofuel Burning

NASA Technical Reports Server (NTRS)

Posfai, Mihaly; Gelencser, Andras; Simonics, Renata; Arato, Krisztina; Li, Jia; Hobbs, Peter V.; Buseck, Peter R.

2004-01-01

Tar balls are amorphous, carbonaceous spherules that occur in the tropospheric aerosol as a result of biomass and biofuel burning. They form a distinct group of particles with diameters typically between 30 and 500 nm and readily identifiable with electron microscopy. Their lack of a turbostratic microstructure distinguishes them from soot, and their morphology and composition (approximately 90 mol% carbon) renders them distinct from other carbonaceous particles. Tar balls are particularly abundant in slightly aged (minutes to hours old) biomass smoke, indicating that they likely form by gas-to-particle conversion within smoke plumes. The material of tar balls is initially hygroscopic; however, the particles become largely insoluble as a result of free radical polymerization of their organic molecules. Consequently, tar balls are primarily externally mixed with other particle types, and they do not appreciably increase in size during aging. When tar balls coagulate with water-bearing particles, their material may partly dissolve and no longer be recognizable as distinct particles. Tar balls may contain organic compounds that absorb sunlight. They are an important, previously unrecognized type of carbonaceous (organic) atmospheric particle.

Sands at Gusev Crater, Mars

NASA Astrophysics Data System (ADS)

Cabrol, Nathalie A.; Herkenhoff, Kenneth; Knoll, Andrew H.; Farmer, Jack; Arvidson, Raymond; Grin, Edmond; Li, Ronxing; Fenton, Lori; Cohen, Barbara; Bell, James F.; Aileen Yingst, R.

2014-05-01

Processes, environments, and the energy associated with the transport and deposition of sand at Gusev Crater are characterized at the microscopic scale through the comparison of statistical moments for particle size and shape distributions. Bivariate and factor analyses define distinct textural groups at 51 sites along the traverse completed by the Spirit rover as it crossed the plains and went into the Columbia Hills. Fine-to-medium sand is ubiquitous in ripples and wind drifts. Most distributions show excess fine material, consistent with a predominance of wind erosion over the last 3.8 billion years. Negative skewness at West Valley is explained by the removal of fine sand during active erosion, or alternatively, by excess accumulation of coarse sand from a local source. The coarse to very coarse sand particles of ripple armors in the basaltic plains have a unique combination of size and shape. Their distribution display significant changes in their statistical moments within the ~400 m that separate the Columbia Memorial Station from Bonneville Crater. Results are consistent with aeolian and/or impact deposition, while the elongated and rounded shape of the grains forming the ripples, as well as their direction of origin, could point to Ma'adim Vallis as a possible source. For smaller particles on the traverse, our findings confirm that aeolian processes have dominated over impact and other processes to produce sands with the observed size and shape patterns across a spectrum of geologic (e.g., ripples and plains soils) and aerographic settings (e.g., wind shadows).

Sands at Gusev Crater, Mars

USGS Publications Warehouse

Cabrol, Nathalie A.; Herkenhoff, Kenneth E.; Knoll, Andrew H.; Farmer, Jack D.; Arvidson, Raymond E.; Grin, E.A.; Li, Ron; Fenton, Lori; Cohen, B.; Bell, J.F.; Yingst, R. Aileen

2014-01-01

Processes, environments, and the energy associated with the transport and deposition of sand at Gusev Crater are characterized at the microscopic scale through the comparison of statistical moments for particle size and shape distributions. Bivariate and factor analyses define distinct textural groups at 51 sites along the traverse completed by the Spirit rover as it crossed the plains and went into the Columbia Hills. Fine-to-medium sand is ubiquitous in ripples and wind drifts. Most distributions show excess fine material, consistent with a predominance of wind erosion over the last 3.8 billion years. Negative skewness at West Valley is explained by the removal of fine sand during active erosion, or alternatively, by excess accumulation of coarse sand from a local source. The coarse to very coarse sand particles of ripple armors in the basaltic plains have a unique combination of size and shape. Their distribution display significant changes in their statistical moments within the ~400 m that separate the Columbia Memorial Station from Bonneville Crater. Results are consistent with aeolian and/or impact deposition, while the elongated and rounded shape of the grains forming the ripples, as well as their direction of origin, could point to Ma'adim Vallis as a possible source. For smaller particles on the traverse, our findings confirm that aeolian processes have dominated over impact and other processes to produce sands with the observed size and shape patterns across a spectrum of geologic (e.g., ripples and plains soils) and aerographic settings (e.g., wind shadows).

Sand wave fields beneath the Loop Current, Gulf of Mexico: Reworking of fan sands

USGS Publications Warehouse

Kenyon, Neil H.; Akhmetzhanov, A.M.; Twichell, D.C.

2002-01-01

Extensive fields of large barchan-like sand waves and longitudinal sand ribbons have been mapped by deep-towed SeaMARC IA sidescan sonar on part of the middle and lower Mississippi Fan that lies in about 3200 m of water. The area is beneath the strongly flowing Loop Current. The bedforms have not been adequately sampled but probably consist of winnowed siliciclastic-foraminiferal sands. The size (about 200 m from wingtip to wingtip) and shape of the large barchans is consistent with a previously observed peak current speed of 30 cm/s, measured 25 m above the seabed. The types of small-scale bedforms and the scoured surfaces of chemical crusts, seen on nearby bottom photographs, indicate that near-bed currents in excess of 30 cm/s may sometimes occur. At the time of the survey the sand transport direction was to the northwest, in the opposite direction to the Loop Current but consistent with there being a deep boundary current along the foot of the Florida Escarpment. Some reworking of the underlying sandy turbidites and debris flow deposits is apparent on the sidescan sonar records. Reworking by deep-sea currents, resulting in erosion and in deposits characterised by coarsening upwards structures and cross-bedding, is a process that has been proposed for sand found in cores in shallower parts of the Gulf of Mexico. This process is more widespread than hitherto supposed. 

Controls on the abruptness of gravel-sand transitions

NASA Astrophysics Data System (ADS)

Venditti, J. G.; Church, M. A.; Lamb, M. P.; Domarad, N.; Rennie, C. D.

2014-12-01

As gravel-bedded rivers fine downstream, they characteristically exhibit an abrupt transition from gravel- to sand-bed. This is the only abrupt transition in grain-size that occurs in the fluvial system and has attracted considerable attention. A number of competing theories have been proposed to account for the abruptness of the transition, including base-level control, attrition of ~10mm gravel to produce sand, and sediment sorting processes. The prevailing theory for the emergence of abrupt transitions is size selective sorting of bimodal sediment wherein gravel deposits due to downstream declining shear stress, fining the bedload until a sand-bed emerges. We explored this hypothesis by examining grain-size, shear stress, gravel mobility and sand suspension thresholds through the gravel-sand transition (GST) of the Fraser River, British Columbia. The Fraser GST is an arrested gravel wedge with patches of gravel downstream of the wedge forming a diffuse extension. There is an abrupt change in bed slope through the transition that leads to an abrupt change in shear stress. The GST, bed-slope change and backwater caused by the ocean are all coincident spatially, which enhances the sharpness of the GST. Interestingly, the bimodal reach of the river occurs downstream of the GST and exhibits no downstream gradients in shear stress, suspended sediment flux, gravel mobility or sand suspension thresholds. This calls into question the prevailing theory for the emergence of an abrupt GST by size selective sorting. We provide evidence, both empirical and theoretical, that suggests the emergence of an abrupt GST is caused by rapid deposition of sand when fine gravel deposits. We argue that the emergence of gravel-sand transitions is a consequence of gravel-bedded rivers adopting a steeper slope than sand-bedded rivers. The abruptness arises because the bed slope required to convey the gravel load fixes the distal location of a terminal gravel wedge, and once the river has

Exceptional marine sand bodies in the Paleozoic of Oklahoma

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fritz, R.D.; Kuykendall, M.D.; Hooker, E.O.

Of the wide variety of sandstone reservoirs in Oklahoma, the most unusual types of sand bodies are present in the Atokan Spiro Sandstone, Devonian Misener Sandstone, and Morrowan lower Morrow Sandstone. The common factors are that upon correlation and mapping these units are channel-like (fluvial-deltaic) in geometry, but from petrographic evidence are quartz-rich shallow-marine units, with the exclusion of intraclastic and diagenetic constituents. Stratigraphic mapping of the Spiro Sandstone of the Arkoma basin indicates two types of sand bodies: channel and sheet. The marine channel-like deposits, 10-150 ft thick, probably were deposited on a paleosurface produced by a pre-Atokan unconformity.more » Examination of cores and outcrop indicate that both the channel and sheet Spiro sands contain shallow-marine fossils, limestones, peloidal chamosite, burrows, and bioturbation, all indicative of a shallow-marine setting. The Misener Sandstone of north-central Oklahoma ranges from 10 to 100 ft thick with sharp boundaries. It was deposited in pre-Frisco/Woodford eroded paleochannels. Core evidence for shallow-marine deposition is glauconite, phosphatic fossils and clasts, burrows, and bioturbation. These were probably deposited in an embayed, estuary-like environment. The lower Morrow Sandstone of the Anadarko basin is similar in geometry, except that the sand bodies are multistoried and multilateral and do not appear to be associated with a regional unconformity. The lower Morrow sandstones, usually 30-60 ft thick. commonly are elongated and deposited parallel to the shoreline. Deposition is inferred to be shallow-marine from marine fossils and glauconite.« less

Tar, nicotine, and carbon monoxide yields of some Nigerian cigarettes.

PubMed Central

Awotedu, A A; Higenbottam, T W; Onadeko, B O

1983-01-01

Fourteen cigarette brands manufactured in Nigeria in 1981 were analysed to determine the tar, nicotine, and carbon monoxide yields. Five of the brands belonged to the high and middle to high tar category (greater than 22 mg/cigarette) and nine to the middle tar (17-22 mg/cigarette) category. None of the cigarettes was in the low to middle and low tar (less than 17 mg/cigarette) category. The nicotine and carbon monoxide yields were similar to those of European cigarettes. Tobacco companies need to manufacture low tar cigarettes in the Third World as is the practice in the economically developed parts of the world. PMID:6619721

VAPOR PRESSURES AND HEATS OF VAPORIZATION OF PRIMARY COAL TARS

DOE Office of Scientific and Technical Information (OSTI.GOV)

Eric M. Suuberg; Vahur Oja

1997-07-01

This project had as its main focus the determination of vapor pressures of coal pyrolysis tars. It involved performing measurements of these vapor pressures and from them, developing vapor pressure correlations suitable for use in advanced pyrolysis models (those models which explicitly account for mass transport limitations). This report is divided into five main chapters. Each chapter is a relatively stand-alone section. Chapter A reviews the general nature of coal tars and gives a summary of existing vapor pressure correlations for coal tars and model compounds. Chapter B summarizes the main experimental approaches for coal tar preparation and characterization whichmore » have been used throughout the project. Chapter C is concerned with the selection of the model compounds for coal pyrolysis tars and reviews the data available to us on the vapor pressures of high boiling point aromatic compounds. This chapter also deals with the question of identifying factors that govern the vapor pressures of coal tar model materials and their mixtures. Chapter D covers the vapor pressures and heats of vaporization of primary cellulose tars. Chapter E discusses the results of the main focus of this study. In summary, this work provides improved understanding of the volatility of coal and cellulose pyrolysis tars. It has resulted in new experimentally verified vapor pressure correlations for use in pyrolysis models. Further research on this topic should aim at developing general vapor pressure correlations for all coal tars, based on their molecular weight together with certain specific chemical characteristics i.e. hydroxyl group content.« less

Plant Community and Nitrogen Deposition as Drivers of Alpha and Beta Diversities of Prokaryotes in Reconstructed Oil Sand Soils and Natural Boreal Forest Soils.

PubMed

Masse, Jacynthe; Prescott, Cindy E; Renaut, Sébastien; Terrat, Yves; Grayston, Sue J

2017-05-01

The Athabasca oil sand deposit is one of the largest single oil deposits in the world. Following surface mining, companies are required to restore soil-like profiles that can support the previous land capabilities. The objective of this study was to assess whether the soil prokaryotic alpha diversity (α-diversity) and β-diversity in oil sand soils reconstructed 20 to 30 years previously and planted to one of three vegetation types (coniferous or deciduous trees and grassland) were similar to those found in natural boreal forest soils subject to wildfire disturbance. Prokaryotic α-diversity and β-diversity were assessed using massively parallel sequencing of 16S rRNA genes. The β-diversity, but not the α-diversity, differed between reconstructed and natural soils. Bacteria associated with an oligotrophic lifestyle were more abundant in natural forest soils, whereas bacteria associated with a copiotrophic lifestyle were more abundant in reconstructed soils. Ammonia-oxidizing archaea were most abundant in reconstructed soils planted with grasses. Plant species were the main factor influencing α-diversity in natural and in reconstructed soils. Nitrogen deposition, pH, and plant species were the main factors influencing the β-diversity of the prokaryotic communities in natural and reconstructed soils. The results highlight the importance of nitrogen deposition and aboveground-belowground relationships in shaping soil microbial communities in natural and reconstructed soils. IMPORTANCE Covering over 800 km 2 , land disturbed by the exploitation of the oil sands in Canada has to be restored. Here, we take advantage of the proximity between these reconstructed ecosystems and the boreal forest surrounding the oil sand mining area to study soil microbial community structure and processes in both natural and nonnatural environments. By identifying key characteristics shaping the structure of soil microbial communities, this study improved our understanding of how

Ultrasound assisted, thermally activated persulfate oxidation of coal tar DNAPLs.

PubMed

Peng, Libin; Wang, Li; Hu, Xingting; Wu, Peihui; Wang, Xueqing; Huang, Chumei; Wang, Xiangyang; Deng, Dayi

2016-11-15

The feasibility of ultrasound assisted, thermally activated persulfate for effective oxidation of twenty 2-6 ringed coal tar PAHs in a biphasic tar/water system and a triphasic tar/soil/water system were investigated and established. The results indicate that ultrasonic assistance, persulfate and elevated reaction temperature are all required to achieve effective oxidation of coal tar PAHs, while the heating needed can be provided by ultrasonic induced heating as well. Further kinetic analysis reveals that the oxidation of individual PAH in the biphasic tar/water system follows the first-order kinetics, and individual PAH oxidation rate is primary determined by the mass transfer coefficients, tar/water interfacial areas, the aqueous solubility of individual PAH and its concentration in coal tar. Based on the kinetic analysis and experimental results, the contributions of ultrasound, persulfate and elevated reaction temperature to PAHs oxidation were characterized, and the effects of ultrasonic intensity and oxidant dosage on PAHs oxidation efficiency were investigated. In addition, the results indicate that individual PAH degradability is closely related to its reactivity as well, and the high reactivity of 4-6 ringed PAHs substantially improves their degradability. Copyright © 2016 Elsevier B.V. All rights reserved.

Modelling spiky acceleration response of dilative sand deposits during earthquakes with emphasis on large post-liquefaction deformation

NASA Astrophysics Data System (ADS)

Wang, Gang; Wei, Xing; Zhao, John

2018-01-01

The acceleration records at some liquefied sand deposits exhibit a distinctive spiky waveform, characterized by strong amplification and high-frequency components. A comprehensive constitutive model was used to analyze the mechanism of such spiky acceleration responses. An idealized single-degree-of-freedom (SDF) system was constructed, in which the force-displacement relation of the spring follows the stress-strain behavior of saturated sand during undrained shearing. The SDF system demonstrated that the spikes are directly related to the strain-hardening behavior of sand during post-liquefaction cyclic shearing. Furthermore, there exists a threshold shear strain length, which is in accordance with the limited amplitude of the fluid-like shear strain generated at instantaneous zero effective stress state during the post-liquefaction stage. The spiky acceleration can only occur when the cyclic shear strain exceeds the threshold shear strain length. It is also revealed that the time intervals between the acceleration spikes increase gradually along with the continuation of shaking because the threshold shear strain length increases gradually and then more time is needed to generate larger shear strain to cause strain hardening. Records at the Kushiro Port site and Port Island site during past earthquakes are simulated through the fully coupled method to validate the presented mechanism.

Fractal-like Tar Ball Aggregates from Wildfire Smoke

DOE Office of Scientific and Technical Information (OSTI.GOV)

Girotto, Giulia; China, Swarup; Bhandari, Janarjan

Tar balls are atmospheric particles abundant in slightly aged biomass burning smoke and have a significant, but highly uncertain, role on Earth's radiative balance. Tar balls are typically detected using electron microscopy; they are resistant to the electron beam, and generally, they are observed as individual spheres. Here, we report new observations of a significant fraction of tar ball aggregates (~27% by number) from samples collected in a plume of the Whitewater-Baldy Complex fire in New Mexico. The structure of these aggregates is fractal-like and follows a scale invariant power law similar to that of soot particles, despite the considerablymore » larger size and smaller number of monomers. We also present observations of tar ball aggregates from four other geographical locations, including from a remote high elevation site in the North Atlantic Ocean. Aggregation affects the particle optical properties and therefore, their climatic impact. We performed numerical simulations based on the observed morphology and estimated the effects of aggregation on the tar balls optical properties. We find that aggregation can enhance single scattering albedo by up to 41%.« less

The extraction of bitumen from western oil sands: Volume 2. Final report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Oblad, A.G.; Dahlstrom, D.A.; Deo, M.D.

1997-11-26

The program is composed of 20 projects, of which 17 are laboratory bench or laboratory pilot scale processes or computer process simulations that are performed in existing facilities on the University of Utah campus in north-east Salt Lake City. These tasks are: (1) coupled fluidized-bed bitumen recovery and coked sand combustion; (2) water-based recovery of bitumen; (3) oil sand pyrolysis in a continuous rotary kiln reactor; (4) oil sand pyrolysis in a large diameter fluidized bed reactor; (5) oil sand pyrolysis in a small diameter fluidized bed reactor; (6) combustion of spent sand in a transport reactor; (7) recovery andmore » upgrading of oil sand bitumen using solvent extraction methods; (8) fixed-bed hydrotreating of Uinta Basin bitumens and bitumen-derived hydrocarbon liquids; (9) ebullieted bed hydrotreating of bitumen and bitumen derived liquids; (10) bitumen upgrading by hydropyrolysis; (11) evaluation of Utah`s major oil sand deposits for the production of asphalt, high-energy jet fuels and other specialty products; (12) characterization of the bitumens and reservoir rocks from the Uinta Basin oil sand deposits; (13) bitumen upgrading pilot plant recommendations; (14) liquid-solid separation and fine tailings thickening; (15) in-situ production of heavy oil from Uinta Basin oil sand deposits; (16) oil sand research and development group analytical facility; and (17) process economics. This volume contains reports on nine of these projects, references, and a bibliography. 351 refs., 192 figs., 65 tabs.« less

77 FR 5833 - Notice of Availability of the Draft Programmatic Environmental Impact Statement for Allocation of...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-02-06

... of the Draft Programmatic Environmental Impact Statement for Allocation of Oil Shale and Tar Sands... of Oil Shale and Tar Sands Resources on Lands Administered by the BLM in Colorado, Utah, and Wyoming... preferred method of commenting. Mail: Addressed to: Oil Shale and Tar Sands Resources Draft Programmatic EIS...

Sydney Tar Ponds Remediation: Experience to China

ERIC Educational Resources Information Center

Liu, Fan; Bryson, Ken A.

2009-01-01

The infamous "Sydney Tar Ponds" are well known as one of the largest toxic waste sites of Canada, due to almost 100 years of steelmaking in Sydney, a once beautiful and peaceful city located on the east side of Cape Breton Island, Nova Scotia. This article begins with a contextual overview of the Tar Ponds issue including a brief…

Effect of Transport and Aging Processes on Metal Speciation in Iron Oxyhydroxide Aggregates, Tar Creek Superfund Site, Oklahoma

NASA Astrophysics Data System (ADS)

Estes, E. R.; Schaider, L. A.; Shine, J. P.; Brabander, D. J.

2010-12-01

Following the cessation of mining activity in the late 20th century, Tar Creek Superfund Site was left highly contaminated by Pb, Zn, and Cd. Tar Creek, which flows through the site and into the Neosho River, has been studied extensively because of its potential to transport metals from the mining site to downstream communities. Previous research identified aggregated iron oxyhydroxide material, which forms when mine seepage mixes with Tar Creek surface water, as a major transport vector of metals. Frequent flooding in Tar Creek deposits aggregates on downstream floodplains, where wetting and drying processes alter the speciation of iron and other metals. This study seeks to better quantify those changes and to determine how transport and aging affects the human and ecological health risk. Sequential extractions of aggregate samples collected from the creek demonstrate that Fe is present in both amorphous (10-35% of Fe extracted) and more crystalline (8-23% of Fe extracted) phases. Substantial portions of heavy metals sorb to amorphous iron oxyhydroxide phases (accounting for 10-30% of Pb and Zn extracted) but are not associated with more crystalline iron oxide phases (representing only 1% or less of the Pb and Zn extracted). Samples have a high organic matter content (18-25% mass loss on ignition), but only Fe was significantly extracted by the oxidizing step targeting organic matter (1-2% of Pb and Zn extracted, but 10-26% of Fe extracted). The majority of metals were extracted by the soluble or residual steps. If metals and organic matter inhibit transformation of amorphous iron oxyhydroxide material to nano and crystalline iron oxides, then a steady-state volume of amorphous iron oxyhydroxide material with a high total sorption capacity may exist within Tar Creek, enhancing the metal flux accommodated by this transport mechanism. Once transported downstream and deposited on floodplains, however, it is hypothesized that repeated changes in soil matrix

76 FR 21003 - Notice of Intent To Prepare a Programmatic Environmental Impact Statement (EIS) and Possible Land...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-04-14

... Allocation of Oil Shale and Tar Sands Resources on Lands Administered by the Bureau of Land Management in... to prepare a Programmatic EIS for Allocation of Oil Shale and Tar Sands Resources on Lands... following methods: Web site: http://blm.gov/st5c . Mail: BLM Oil Shale and Tar Sands Resources Leasing...

Rebound of a coal tar creosote plume following partial source zone treatment with permanganate.

PubMed

Thomson, N R; Fraser, M J; Lamarche, C; Barker, J F; Forsey, S P

2008-11-14

The long-term management of dissolved plumes originating from a coal tar creosote source is a technical challenge. For some sites stabilization of the source may be the best practical solution to decrease the contaminant mass loading to the plume and associated off-site migration. At the bench-scale, the deposition of manganese oxides, a permanganate reaction byproduct, has been shown to cause pore plugging and the formation of a manganese oxide layer adjacent to the non-aqueous phase liquid creosote which reduces post-treatment mass transfer and hence mass loading from the source. The objective of this study was to investigate the potential of partial permanganate treatment to reduce the ability of a coal tar creosote source zone to generate a multi-component plume at the pilot-scale over both the short-term (weeks to months) and the long-term (years) at a site where there is >10 years of comprehensive synoptic plume baseline data available. A series of preliminary bench-scale experiments were conducted to support this pilot-scale investigation. The results from the bench-scale experiments indicated that if sufficient mass removal of the reactive compounds is achieved then the effective solubility, aqueous concentration and rate of mass removal of the more abundant non-reactive coal tar creosote compounds such as biphenyl and dibenzofuran can be increased. Manganese oxide formation and deposition caused an order-of-magnitude decrease in hydraulic conductivity. Approximately 125 kg of permanganate were delivered into the pilot-scale source zone over 35 days, and based on mass balance estimates <10% of the initial reactive coal tar creosote mass in the source zone was oxidized. Mass discharge estimated at a down-gradient fence line indicated >35% reduction for all monitored compounds except for biphenyl, dibenzofuran and fluoranthene 150 days after treatment, which is consistent with the bench-scale experimental results. Pre- and post-treatment soil core data

Aerolian erosion, transport, and deposition of volcaniclastic sands among the shifting sand dunes, Christmas Lake Valley, Oregon: TIMS image analysis

NASA Technical Reports Server (NTRS)

Edgett, Kenneth S.; Ramsey, Michael S.; Christensen, Philip R.

1995-01-01

Remote sensing is a tool that, in the context of aeolian studies, offers a synoptic view of a dune field, sand sea, or entire desert region. Blount et al. (1990) presented one of the first studies demonstrating the power of multispectral images for interpreting the dynamic history of an aeolian sand sea. Blount's work on the Gran Desierto of Mexico used a Landsat TM scene and a linear spectral mixing model to show where different sand populations occur and along what paths these sands may have traveled before becoming incorporated into dunes. Interpretation of sand transport paths and sources in the Gran Desierto led to an improved understanding of the origin and Holocene history of the dunes. With the anticipated advent of the EOS-A platform and ASTER thermal infrared capability in 1998, it will become possible to look at continental sand seas and map sand transport paths using 8-12 mu m bands that are well-suited to tracking silicate sediments. A logical extension of Blount's work is to attempt a similar study using thermal infrared images. One such study has already begun by looking at feldspar, quartz, magnetite, and clay distributions in the Kelso Dunes of southern California. This paper describes the geology and application of TIMS image analysis of a less-well known Holocene dune field in south central Oregon using TIMS data obtained in 1991.

Solid fossil-fuel recovery by electrical induction heating in situ - A proposal

NASA Astrophysics Data System (ADS)

Fisher, S.

1980-04-01

A technique, termed electrical induction heating, is proposed for in situ processes of energy production from solid fossil fuels, such as bitumen production from underground distillation of oil sand; oil by underground distillation of oil shale; petroleum from heavy oil by underground mobilization of heavy oil, from either residues of conventional liquid petroleum deposits or new deposits of viscous oil; methane and coal tar from lignite and coal deposits by underground distillation of coal; and generation of electricity by surface combustion of low calorific-value gas from underground coke gasification by combustion of the organic residue left from the underground distillation of coal by induction heating. A method of surface distillation of mined coking coal by induction heating to produce coke, methane, and coal tar is also proposed.

48 CFR Appendix to Part 1252 - Tar Matrix

Code of Federal Regulations, 2010 CFR

2010-10-01

... 48 Federal Acquisition Regulations System 5 2010-10-01 2010-10-01 false Tar Matrix Appendix to Part 1252 Federal Acquisition Regulations System DEPARTMENT OF TRANSPORTATION CLAUSES AND FORMS SOLICITATION PROVISIONS AND CONTRACT CLAUSES Pt. 1252, App. Appendix to Part 1252—Tar Matrix ER27DE05.000...

Integrated Biomass Gasification with Catalytic Partial Oxidation for Selective Tar Conversion

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhang, Lingzhi; Wei, Wei; Manke, Jeff

Biomass gasification is a flexible and efficient way of utilizing widely available domestic renewable resources. Syngas from biomass has the potential for biofuels production, which will enhance energy security and environmental benefits. Additionally, with the successful development of low Btu fuel engines (e.g. GE Jenbacher engines), syngas from biomass can be efficiently used for power/heat co-generation. However, biomass gasification has not been widely commercialized because of a number of technical/economic issues related to gasifier design and syngas cleanup. Biomass gasification, due to its scale limitation, cannot afford to use pure oxygen as the gasification agent that used in coal gasification.more » Because, it uses air instead of oxygen, the biomass gasification temperature is much lower than well-understood coal gasification. The low temperature leads to a lot of tar formation and the tar can gum up the downstream equipment. Thus, the biomass gasification tar removal is a critical technology challenge for all types of biomass gasifiers. This USDA/DOE funded program (award number: DE-FG36-O8GO18085) aims to develop an advanced catalytic tar conversion system that can economically and efficiently convert tar into useful light gases (such as syngas) for downstream fuel synthesis or power generation. This program has been executed by GE Global Research in Irvine, CA, in collaboration with Professor Lanny Schmidt's group at the University of Minnesota (UoMn). Biomass gasification produces a raw syngas stream containing H2, CO, CO2, H2O, CH4 and other hydrocarbons, tars, char, and ash. Tars are defined as organic compounds that are condensable at room temperature and are assumed to be largely aromatic. Downstream units in biomass gasification such as gas engine, turbine or fuel synthesis reactors require stringent control in syngas quality, especially tar content to avoid plugging (gum) of downstream equipment. Tar- and ash-free syngas streams are a

Geologic assessments and characterization of marine sand resources - Gulf of Mexico region

USGS Publications Warehouse

Williams, S. Jeffress; Cichon, Helana A.

1993-01-01

The U.S. Geological Survey conducts geologic surveys and research in marine areas of the United States and its territories and possessions. An objective in some of the investigations is locating and evaluating marine sand and gravel resources and interpretation of the origins of the sand body deposits. Results from such studies over the past 30 years show that many extremely large deposits are located close to expanding metropolitan areas, which have a need for aggregate materials for construction, and near-developed coastal areas, where beach replenishment may be used to mitigate coastal erosion. The Gulf of Mexico continental shelf from the Florida Peninsula to the Mexico border is an enormous area, but little attention has been directed on sand and gravel resources. Based on limited surveys, the total sand and gravel resources for the entire Gulf of Mexico is estimated to be 269 billion cubic meters. However, the sand tends to be fine-grained and is often mixed with mud; gravel deposits, except for shell, are mostly nonexistent.

An enhanced approach for the use of satellite-derived leaf area index values in dry deposition modeling in the Athabasca oil sands region.

PubMed

Davies, Mervyn; Cho, Sunny; Spink, David; Pauls, Ron; Desilets, Michael; Shen, Yan; Bajwa, Kanwardeep; Person, Reid

2016-12-15

In the Athabasca oil sands region (AOSR) of Northern Alberta, the dry deposition of sulphur and nitrogen compounds represents a major fraction of total (wet plus dry) deposition due to oil sands emissions. The leaf area index (LAI) is a critical parameter that affects the dry deposition of these gaseous and particulate compounds to the surrounding boreal forest canopy. For this study, LAI values based on Moderate Resolution Imaging Spectroradiometer satellite imagery were obtained and compared to ground-based measurements, and two limitations with the satellite data were identified. The satellite LAI data firstly represents one-sided LAI values that do not account for the enhanced LAI associated with needle leaf geometry, and secondly, underestimates LAI in winter-time northern latitude regions. An approach for adjusting satellite LAI values for different boreal forest cover types, as a function of time of year, was developed to produce more representative LAI values that can be used by air quality sulphur and nitrogen deposition models. The application of the approach increases the AOSR average LAI for January from 0.19 to 1.40, which represents an increase of 637%. Based on the application of the CALMET/CALPUFF model system, this increases the predicted regional average dry deposition of sulphur and nitrogen compounds for January by factors of 1.40 to 1.30, respectively. The corresponding AOSR average LAI for July increased from 2.8 to 4.0, which represents an increase of 43%. This increases the predicted regional average dry deposition of sulphur and nitrogen compounds for July by factors of 1.28 to 1.22, respectively. These findings reinforce the importance of the LAI metric for predicting the dry deposition of sulphur and nitrogen compounds. While satellite data can provide enhanced spatial and temporal resolution, adjustments are identified to overcome associated limitations. This work is considered to have application for other deposition model studies where

Geologic map of Great Sand Dunes National Park, Colorado

USGS Publications Warehouse

Madole, Richard F.; VanSistine, D. Paco; Romig, Joseph H.

2016-10-20

Geologic mapping was begun after a range fire swept the area of what is now the Great Sand Dunes National Park in April 2000. The park spans an area of 437 square kilometers (or about 169 square miles), of which 98 percent is blanketed by sediment of Quaternary age, the Holocene and Pleistocene Epochs; hence, this geologic map of the Great Sand Dunes National Park is essentially a surficial geologic map. These surficial deposits are diverse and include sediment of eolian (windblown), alluvial (stream and sheetwash), palustrine (wetlands and marshes), lacustrine (lake), and mass-wasting (landslides) origin. Sediment of middle and late Holocene age, from about 8,000 years ago to the present, covers about 80 percent of the park.Fluctuations in groundwater level during Holocene time caused wetlands on the nearby lowland that bounds the park on the west to alternately expand and contract. These fluctuations controlled the stability or instability of eolian sand deposits on the downwind (eastern) side of the lowland. When groundwater level rose, playas became lakes, and wet or marshy areas formed in many places. When the water table rose, spring-fed streams filled their channels and valley floors with sediment. Conversely, when groundwater level fell, spring-fed streams incised their valley floors, and lakes, ponds, and marshes dried up and became sources of windblown sand.Discharge in streams draining the west flank of the Sangre de Cristo Range is controlled primarily by snowmelt and flow is perennial until it reaches the mountain front, beyond which streams begin losing water at a high rate as the water soaks into the creek beds. Even streams originating in the larger drainage basins, such as Sand and Medano Creeks, generally do not extend much more than 4 km (about 2.5 miles) beyond where they exit the mountains.The Great Sand Dunes contain the tallest dunes (maximum height about 750 feet, or 230 m) in North America. These dunes cover an area of 72 square kilometers

Banded TARs in Iapygia

NASA Image and Video Library

2014-09-10

The tropics of Mars are commonly littered with small bright ripples that were somehow shaped by the wind. NASA Mars Reconnaissance Orbiter might provide a valuable clue to the formation of transverse aeolian ridges TARs elsewhere on Mars.

Emplacement and dewatering of the world's largest exposed sand injectite complex

NASA Astrophysics Data System (ADS)

Sherry, Timothy J.; Rowe, Christie D.; Kirkpatrick, James D.; Brodsky, Emily E.

2012-08-01

Sandstone injectites form by up or down-section flow of a mobilized sand slurry through fractures in overlying rock. They act as reservoirs and high-permeability conduits through lower permeability rock in hydrocarbon systems. The Yellow Bank Creek Complex, Santa Cruz County, California is the largest known exposure of a sandstone injectite in the world. The complex contains granular textures that record processes of sand slurry flow, multiple pore fluids, and dewatering after emplacement. The injection was initially mobilized from a source containing both water and hydrocarbons. The water-sand slurry reached emplacement depth first, due to lower fluid viscosity. As the sand slurry emplaced, the transition from slurry flow to pore water percolation occurred. This transition resulted in preferred flow channels ˜6 mm wide in which sand grains were weakly aligned (laminae). The hydrocarbon-sand slurry intruded the dewatering sands and locally deformed the laminae. Compaction of the injectite deposit and pore fluid escape caused spaced compaction bands and dewatering pipes which created convolutions of the laminae. The hydrocarbon-rich sand slurry is preserved today as dolomite-cemented sand with oil inclusions. The laminae in this injectite are easily detected due to preferential iron oxide-cementation of the well-aligned sand laminae, and lack of cement in the alternating laminae. Subtle textures like these may develop during sand flow and be present but difficult to detect in other settings. They may explain permeability anisotropy in other sand deposits.

The Halekulani Sand Channel and Makua Shelf sediment deposits: Are they a sand resource for replenishing Waikiki's beaches?

USGS Publications Warehouse

Hampton, M.A.; Fletcher, C. H.; Barry, J.H.; Lemmo, S.J.; ,

2000-01-01

The Halekulani Sand Channel and the Makua Shelf off the south shore of Oahu contain at least 1.3 million m3 of sediment that is a possible resource for nourishing degraded sections of Waikiki Beach. A sidescan sonar survey indicates continuous sediment cover within the channel and on the shelf, and samples from the top and bottom of vibracores from the channel and shelf contain from 29% to 77% of grains between 0 to 2.5 phi (1 to 0.177 mm), the size range of four samples from Waikiki Beach. Compositional analyses indicate high variability, but the vibracore samples normally have relatively high Halimeda content compared to beach sand samples. Laboratory tests show a positive correlation of abrasion with Halimeda content, suggesting that the offshore sediment would abrade more than beach sediment under nearshore wave action. The common gray color of the offshore sediment can be aesthetically undesirable for sand on popular tourist beaches such as Waikiki; however, visual observation of native beach sand indicates that a significant component of gray color is endemic to many Hawaiian beaches. The gray color was removed in the laboratory by soaking in heated hydrogen peroxide. The geological properties of the offshore sediment indicate potential as a resource for beach nourishment, but industrial treatment might be necessary to remove excess fine and coarse grains, and possibly the gray color. Further, the abrasion potential might have to be considered in calculating beach sand losses over time.

29 CFR 1910.1002 - Coal tar pitch volatiles; interpretation of term.

Code of Federal Regulations, 2013 CFR

2013-07-01

... 29 Labor 6 2013-07-01 2013-07-01 false Coal tar pitch volatiles; interpretation of term. 1910.1002... Hazardous Substances § 1910.1002 Coal tar pitch volatiles; interpretation of term. As used in § 1910.1000 (Table Z-1), coal tar pitch volatiles include the fused polycyclic hydrocarbons which volatilize from the...

29 CFR 1910.1002 - Coal tar pitch volatiles; interpretation of term.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 29 Labor 6 2010-07-01 2010-07-01 false Coal tar pitch volatiles; interpretation of term. 1910.1002... Hazardous Substances § 1910.1002 Coal tar pitch volatiles; interpretation of term. As used in § 1910.1000 (Table Z-1), coal tar pitch volatiles include the fused polycyclic hydrocarbons which volatilize from the...

29 CFR 1910.1002 - Coal tar pitch volatiles; interpretation of term.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 29 Labor 6 2011-07-01 2011-07-01 false Coal tar pitch volatiles; interpretation of term. 1910.1002... Hazardous Substances § 1910.1002 Coal tar pitch volatiles; interpretation of term. As used in § 1910.1000 (Table Z-1), coal tar pitch volatiles include the fused polycyclic hydrocarbons which volatilize from the...

29 CFR 1910.1002 - Coal tar pitch volatiles; interpretation of term.

Code of Federal Regulations, 2012 CFR

2012-07-01

... 29 Labor 6 2012-07-01 2012-07-01 false Coal tar pitch volatiles; interpretation of term. 1910.1002... Hazardous Substances § 1910.1002 Coal tar pitch volatiles; interpretation of term. As used in § 1910.1000 (Table Z-1), coal tar pitch volatiles include the fused polycyclic hydrocarbons which volatilize from the...

29 CFR 1910.1002 - Coal tar pitch volatiles; interpretation of term.

Code of Federal Regulations, 2014 CFR

2014-07-01

... 29 Labor 6 2014-07-01 2013-07-01 true Coal tar pitch volatiles; interpretation of term. 1910.1002... Hazardous Substances § 1910.1002 Coal tar pitch volatiles; interpretation of term. As used in § 1910.1000 (Table Z-1), coal tar pitch volatiles include the fused polycyclic hydrocarbons which volatilize from the...

Coal tar-containing asphalt - resource or hazardous waste?

DOE Office of Scientific and Technical Information (OSTI.GOV)

Andersson-Skold, Y.; Andersson, K.; Lind, B.

2007-09-30

Coal tar was used in Sweden for the production of asphalt and for the drenching of stabilization gravel until 1973. The tar has high concentrations of polycyclic aromatic hydrocarbons (PAH), some of which may be strongly carcinogenic. Approximately 20 million tonnes of tar-containing asphalt is present in the public roads in Sweden. Used asphalt from rebuilding can be classified as hazardous waste according to the Swedish Waste Act. The cost of treating the material removed as hazardous waste can be very high due to the large amount that has to be treated, and the total environmental benefit is unclear. Themore » transport of used asphalt to landfill or combustion will affect other environmental targets. The present project, based on three case studies of road projects in Sweden, evaluates the consequences of four scenarios for handling the material: reuse, landfill, biological treatment, and incineration. The results show that reuse of the coal tar-containing materials in new road construction is the most favorable alternative in terms of cost, material use, land use, energy consumption, and air emissions.« less

Sand Volcano Following Earthquake

NASA Technical Reports Server (NTRS)

1989-01-01

Sand boil or sand volcano measuring 2 m (6.6 ft.) in length erupted in median of Interstate Highway 80 west of the Bay Bridge toll plaza when ground shaking transformed loose water-saturated deposit of subsurface sand into a sand-water slurry (liquefaction) in the October 17, 1989, Loma Prieta earthquake. Vented sand contains marine-shell fragments. Sand and soil grains have faces that can cause friction as they roll and slide against each other, or even cause sticking and form small voids between grains. This complex behavior can cause soil to behave like a liquid under certain conditions such as earthquakes or when powders are handled in industrial processes. Mechanics of Granular Materials (MGM) experiments aboard the Space Shuttle use the microgravity of space to simulate this behavior under conditions that carnot be achieved in laboratory tests on Earth. MGM is shedding light on the behavior of fine-grain materials under low effective stresses. Applications include earthquake engineering, granular flow technologies (such as powder feed systems for pharmaceuticals and fertilizers), and terrestrial and planetary geology. Nine MGM specimens have flown on two Space Shuttle flights. Another three are scheduled to fly on STS-107. The principal investigator is Stein Sture of the University of Colorado at Boulder. (Credit: J.C. Tinsley, U.S. Geological Survey)

An Old-Growth Definition for Sand Pine Forests

Treesearch

Kenneth W. Outcalt

1997-01-01

Sand pine scrub, Society of American Foresters cover type 69 (Eyre 1980), grows on deep, droughty, infertile sands of marine and aeolian origin. Water and wind formed these features as sea levels fluctuated during past glacial and interglacial periods (Kurz 1942, Laessle 1958, Brooks 1972). Because of washing and sorting during transport and deposition, soil parent...

Interpreting Hydraulic Conditions from Morphology, Sedimentology, and Grain Size of Sand Bars in the Colorado River in Grand Canyon

NASA Astrophysics Data System (ADS)

Rubin, D. M.; Topping, D. J.; Schmidt, J. C.; Grams, P. E.; Buscombe, D.; East, A. E.; Wright, S. A.

2015-12-01

During three decades of research on sand bars and sediment transport in the Colorado River in Grand Canyon, we have collected unprecedented quantities of data on bar morphology, sedimentary structures, grain size of sand on the riverbed (~40,000 measurements), grain size of sand in flood deposits (dozens of vertical grain-size profiles), and time series of suspended sediment concentration and grain size (more than 3 million measurements using acoustic and laser-diffraction instruments sampling every 15 minutes at several locations). These data, which include measurements of flow and suspended sediment as well as sediment within the deposits, show that grain size within flood deposits generally coarsens or fines proportionally to the grain size of sediment that was in suspension when the beds were deposited. The inverse problem of calculating changing flow conditions from a vertical profile of grain size within a deposit is difficult because at least two processes can cause similar changes. For example, upward coarsening in a deposit can result from either an increase in discharge of the flow (causing coarser sand to be transported to the depositional site), or from winnowing of the upstream supply of sand (causing suspended sand to coarsen because a greater proportion of the bed that is supplying sediment is covered with coarse grains). These two processes can be easy to distinguish where suspended-sediment observations are available: flow-regulated changes cause concentration and grain size of sand in suspension to be positively correlated, whereas changes in supply can cause concentration and grain size of sand in suspension to be negatively correlated. The latter case (supply regulation) is more typical of flood deposits in Grand Canyon.

Assessment of sand quality on concrete performance : examination of acidic and sulfate/sulfide-bearing sands.

DOT National Transportation Integrated Search

2014-12-01

The purpose of this research is to examine how the presence of sulfide- and sulfate-containing : minerals in acidic aggregates may affect the properties of mortar and concrete. Analyses were : performed to compare two sands from a deposit in the Geor...

Transformation-associated recombination (TAR) cloning for genomics studies and synthetic biology

PubMed Central

Kouprina, Natalay; Larionov, Vladimir

2016-01-01

Transformation-associated recombination (TAR) cloning represents a unique tool for isolation and manipulation of large DNA molecules. The technique exploits a high level of homologous recombination in the yeast Sacharomyces cerevisiae. So far, TAR cloning is the only method available to selectively recover chromosomal segments up to 300 kb in length from complex and simple genomes. In addition, TAR cloning allows the assembly and cloning of entire microbe genomes up to several Mb as well as engineering of large metabolic pathways. In this review, we summarize applications of TAR cloning for functional/structural genomics and synthetic biology. PMID:27116033

Offshore sand resources for coastal erosion control in Louisiana

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ramsey, K.E.; Penland, S.; McBride, R.A.

1990-09-01

An inventory of existing geophysical data supplemented by more than 15,000 km of high-resolution seismic profiles and 400 vibracores collected cooperatively by the Louisiana Geological Survey and US Geological Survey since 1981 indicates that a wide range of aggregate minerals occurs on the continental shelf in a variety of depositional settings. The distribution of these deposits is controlled by the geometry of the preexisting fluvial and deltaic channel systems and the stratigraphic signature of the Holocene Transgression across these features. The geology of coastal and offshore Louisiana is tied to the depositional history of the Mississippi River. Offshore of themore » delta plain, five types of aggregate sources can be identified: inner shelf shoals, submerged barrier islands, tidal inlets, distributary channels, and barrier platforms. This paper describes the geology of offshore Louisiana, the available geophysical data sets, and the distribution of aggregate mineral resources. On the continental shelf of the Mississippi River delta plain, two extensive seismic survey grids have been developed by the Louisiana Geological Survey and US Geological Survey. The most prospective resources found are the huge sand bodies of Ship Shoal and associated distributaries, Cat Island Pass tidal channels and associated tidal deltas, and Barataria Pass/Grand Terre tidal channels and associated tidal deltas. East of the mouth of the Mississippi River are the Chandeleur Islands, where LGS identified seven major sand resource targets, truncated barrier-spit and tidal inlet deposits, submerged beach ridges, and distributaries associated with abandoned St. Bernard delta complexes. Abundant sand resources can be found in offshore Louisiana. Many of the sand bodies contain heavy minerals, but their concentration and distribution is unknown. Other potential sand resources not yet adequately explored include Sabine Bank, the Outer Shoal, and the St. Bernard shoal.« less

Coal tar induces AHR-dependent skin barrier repair in atopic dermatitis

PubMed Central

van den Bogaard, Ellen H.; Bergboer, Judith G.M.; Vonk-Bergers, Mieke; van Vlijmen-Willems, Ivonne M.J.J.; Hato, Stanleyson V.; van der Valk, Pieter G.M.; Schröder, Jens Michael; Joosten, Irma; Zeeuwen, Patrick L.J.M.; Schalkwijk, Joost

2013-01-01

Topical application of coal tar is one of the oldest therapies for atopic dermatitis (AD), a T helper 2 (Th2) lymphocyte–mediated skin disease associated with loss-of-function mutations in the skin barrier gene, filaggrin (FLG). Despite its longstanding clinical use and efficacy, the molecular mechanism of coal tar therapy is unknown. Using organotypic skin models with primary keratinocytes from AD patients and controls, we found that coal tar activated the aryl hydrocarbon receptor (AHR), resulting in induction of epidermal differentiation. AHR knockdown by siRNA completely abrogated this effect. Coal tar restored filaggrin expression in FLG-haploinsufficient keratinocytes to wild-type levels, and counteracted Th2 cytokine–mediated downregulation of skin barrier proteins. In AD patients, coal tar completely restored expression of major skin barrier proteins, including filaggrin. Using organotypic skin models stimulated with Th2 cytokines IL-4 and IL-13, we found coal tar to diminish spongiosis, apoptosis, and CCL26 expression, all AD hallmarks. Coal tar interfered with Th2 cytokine signaling via dephosphorylation of STAT6, most likely due to AHR-regulated activation of the NRF2 antioxidative stress pathway. The therapeutic effect of AHR activation herein described opens a new avenue to reconsider AHR as a pharmacological target and could lead to the development of mechanism-based drugs for AD. PMID:23348739

Coal tar induces AHR-dependent skin barrier repair in atopic dermatitis.

PubMed

van den Bogaard, Ellen H; Bergboer, Judith G M; Vonk-Bergers, Mieke; van Vlijmen-Willems, Ivonne M J J; Hato, Stanleyson V; van der Valk, Pieter G M; Schröder, Jens Michael; Joosten, Irma; Zeeuwen, Patrick L J M; Schalkwijk, Joost

2013-02-01

Topical application of coal tar is one of the oldest therapies for atopic dermatitis (AD), a T helper 2 (Th2) lymphocyte-mediated skin disease associated with loss-of-function mutations in the skin barrier gene, filaggrin (FLG). Despite its longstanding clinical use and efficacy, the molecular mechanism of coal tar therapy is unknown. Using organotypic skin models with primary keratinocytes from AD patients and controls, we found that coal tar activated the aryl hydrocarbon receptor (AHR), resulting in induction of epidermal differentiation. AHR knockdown by siRNA completely abrogated this effect. Coal tar restored filaggrin expression in FLG-haploinsufficient keratinocytes to wild-type levels, and counteracted Th2 cytokine-mediated downregulation of skin barrier proteins. In AD patients, coal tar completely restored expression of major skin barrier proteins, including filaggrin. Using organotypic skin models stimulated with Th2 cytokines IL-4 and IL-13, we found coal tar to diminish spongiosis, apoptosis, and CCL26 expression, all AD hallmarks. Coal tar interfered with Th2 cytokine signaling via dephosphorylation of STAT6, most likely due to AHR-regulated activation of the NRF2 antioxidative stress pathway. The therapeutic effect of AHR activation herein described opens a new avenue to reconsider AHR as a pharmacological target and could lead to the development of mechanism-based drugs for AD.

Sampling of tar from sewage sludge gasification using solid phase adsorption.

PubMed

Ortiz González, Isabel; Pérez Pastor, Rosa Ma; Sánchez Hervás, José Ma

2012-06-01

Sewage sludge is a residue from wastewater treatment plants which is considered to be harmful to the environment and all living organisms. Gasification technology is a potential source of renewable energy that converts the sewage sludge into gases that can be used to generate energy or as raw material in chemical synthesis processes. But tar produced during gasification is one of the problems for the implementation of the gasification technology. Tar can condense on pipes and filters and may cause blockage and corrosion in the engines and turbines. Consequently, to minimize tar content in syngas, the ability to quantify tar levels in process streams is essential. The aim of this work was to develop an accurate tar sampling and analysis methodology using solid phase adsorption (SPA) in order to apply it to tar sampling from sewage sludge gasification gases. Four types of commercial SPA cartridges have been tested to determine the most suitable one for the sampling of individual tar compounds in such streams. Afterwards, the capacity, breakthrough volume and sample stability of the Supelclean™ ENVI-Carb/NH(2), which is identified as the most suitable, have been determined. Basically, no significant influences from water, H(2)S or NH(3) were detected. The cartridge was used in sampling real samples, and comparable results were obtained with the present and traditional methods.

Probing interaction of a fluorescent ligand with HIV TAR RNA

NASA Astrophysics Data System (ADS)

Qi, Liang; Zhang, Jing; He, Tian; Huo, Yuan; Zhang, Zhi-Qi

2017-02-01

Trans-activator of Transcription (Tat) antagonists could block the interaction between Tat protein and its target, trans-activation responsive region (TAR) RNA, to inhibit Tat function and prevent human immunodeficiency virus type 1 (HIV-1) replication. For the first time, a small fluorescence ligand, ICR 191, was found to interact with TAR RNA at the Tat binding site and compete with Tat. It was also observed that the fluorescence of ICR 191 could be quenched when binding to TAR RNA and recovered when discharged via competition with Tat peptide or a well-known Tat inhibitor, neomycin B. The binding parameters of ICR 191 to TAR RNA were determined through theoretical calculations. Mass spectrometry, circular dichroism and molecular docking were used to further confirm the interaction of ICR 191 with TAR RNA. Inspired by these discoveries, a primary fluorescence model for the discovery of Tat antagonists was built using ICR 191 as a fluorescence indicator and the feasibility of this model was evaluated. This ligand-RNA interaction could provide a new strategy for research aimed at discovering Tat antagonists.

Thermocatalytic treatment of biomass tar model compounds via radio frequency.

PubMed

Anis, Samsudin; Zainal, Z A; Bakar, M Z A

2013-05-01

A new effective RF tar thermocatalytic treatment process with low energy intensive has been proposed to remove tar from biomass gasification. Toluene and naphthalene as biomass tar model compounds were removed via both thermal and catalytic treatment over a wide temperature range from 850 °C to 1200 °C and 450 °C to 900 °C, respectively at residence time of 0-0.7 s. Thermal characteristics of the new technique are also described in this paper. This study clearly clarified that toluene was much easier to be removed than naphthalene. Soot was found as the final product of thermal treatment of the tar model and completely removed during catalytic treatment. Radical reactions generated by RF non-thermal effect improve the tar removal. The study showed that Y-zeolite has better catalytic activity compared to dolomite on toluene and naphthalene removal due to its acidic nature and large surface area, even at lower reaction temperature of about 550 °C. Copyright © 2013 Elsevier Ltd. All rights reserved.

Assessment of tar pollution on the United Arab emirates beaches

DOE Office of Scientific and Technical Information (OSTI.GOV)

Abu-Hilal, A.H.; Khordagui, H.K.

1993-01-01

In light of the inadequate information concerning stranded tar on the southwest beaches of the Arabian Gulf and the Gulf of Oman, particularly following the massive oil releases during the Gulf War, the present investigation was designed to provide reference-integrated information on the nature, location, and levels of stranded tar balls on the beaches of the United Arab Emirates (UAE). The recorded levels appeared to be higher than expected or previously reported. The tar distribution pattern, in addition to the degree of weathering, indicates that the massive oil release during the Gulf War did not reach the UAE shorelines. Themore » highest reported levels of stranded tar ever recorded in the Arabian Gulf at Jabal Dhannah apparently originated from oil spills and tankers' ballast water at the main oil terminal at the Al-Ruwaiss oil refinery some 10 km to the east. The surprising, relatively high levels of stranded tar on the beaches of the Gulf of Oman were solely attributed to the heavy navigation traffic close to the shorelines. 19 refs., 2 figs., 3 tabs.« less

Early Pliocene Hiatus in Sand Output by the Colorado River: Evidence From Marine Deposits in the Salton Trough, Southern California

NASA Astrophysics Data System (ADS)

Dorsey, R. J.; Bykerk-Kauffman, A.

2015-12-01

Early Pliocene deposits in the western Salton Trough preserve a high-fidelity record of sediment dispersal into the marine realm during initiation and early evolution of the Colorado River (CR). Grain-size fractionation, sediment routing, and transport dynamics of the early CR delta are recorded in sediments of the Fish Creek - Vallecito basin, which was located ~100 km south of Yuma along the transform plate boundary at 5 Ma. Early Pliocene delivery of CR sand to the basin took place in two distinct pulses: (1) deposition of sandy turbidites (Wind Caves Mbr of the Latrania Fm) in a restricted submarine canyon at Split Mt Gorge between ~5.3 and 5.1 Ma; and (2) progradation of a thick, widespread, coarsening-up deltaic sequence of marine mudstone, sandstone, and coquinas (Deguynos Fm) between ~4.8 and 4.2 Ma. Estimated flux of CR sediment during Wind Caves deposition was weak (~3-5 Mt/yr) compared to the long-term average (172±64 Mt/yr). The two pulses of CR sand input are separated by the Coyote Clay (CC, ~5.1-4.8 Ma), a regionally correlable, greenish-yellow-weathering marine claystone unit at the base of the Deguynos Fm. CC gradationally overlies Wind Caves turbidites in the area of the paleocanyon. In contrast, in the Coyote Mts 15-23 km to the south and SE, CC rests on coarse-grained locally-derived late Miocene sedimentary rocks, Alverson volcanics, and metamorphic basement rock along a regional unconformity. Identical claystone facies occur in the NW Indio Hills (restores to Yuma at the mouth of the CR at 5 Ma), and Sierra Cucapa in Mexico (~200 km south of Yuma at 5 Ma). Marine localities outside of the Wind Caves paleocanyon experienced slow to negligible sedimentation along a rugged rocky shoreline until abrupt arrival of CR-derived clay. CC accumulated in a sand-starved, pro-delta marine setting (Winker, 1987) over an inferred N-S distance of ~200 km. We therefore reject an alternate hypothesis that CC accumulated on the muddy slope of the prograding CR

Tar Production from Biomass Pyrolysis in a Fluidized Bed Reactor: A Novel Turbulent Multiphase Flow Formulation

NASA Technical Reports Server (NTRS)

Bellan, J.; Lathouwers, D.

2000-01-01

A novel multiphase flow model is presented for describing the pyrolysis of biomass in a 'bubbling' fluidized bed reactor. The mixture of biomass and sand in a gaseous flow is conceptualized as a particulate phase composed of two classes interacting with the carrier gaseous flow. The solid biomass is composed of three initial species: cellulose, hemicellulose and lignin. From each of these initial species, two new solid species originate during pyrolysis: an 'active' species and a char, thus totaling seven solid-biomass species. The gas phase is composed of the original carrier gas (steam), tar and gas; the last two species originate from the volumetric pyrolysis reaction. The conservation equations are derived from the Boltzmann equations through ensemble averaging. Stresses in the gaseous phase are the sum of the Newtonian and Reynolds (turbulent) contributions. The particulate phase stresses are the sum of collisional and Reynolds contributions. Heat transfer between phases, and heat transfer between classes in the particulate phase is modeled, the last resulting from collisions between sand and biomass. Closure of the equations must be performed by modeling the Reynolds stresses for both phases. The results of a simplified version (first step) of the model are presented.

Radon, radionuclides and the Cretaceous Folkestone Sands - gamma spectroscopy and geochemical analysis of silver sands and associated deposits in the SE of England.

NASA Astrophysics Data System (ADS)

Gillmore, Gavin; Al-Rafai, Yousef; Flowers, Alan

2017-04-01

Radon concentrations in a historic sand mine in Surrey, UK (Reigate Caves), have been measured by both real-time and time-averaged methods over a number of years. These mines are not identified as being in a 'Radon Affected Area' as defined by Public Health England, although concentrations show a summer level of 640 Bqm3 +-44 Bqm3. Average radon concentrations (September 2013 to January 2014) in Reigate caves were above the UK 200 Bqm3 domestic Action Level, above the UK domestic Target Level (of 100 Bqm3) but below the current workplace Action Level of 400 Bqm3. By way of a comparison radon has also been measured in nearby Dorking (South Street Caves). These enigmatic caves were not mined for sand for glass manufacture as Reigate Caves were and there is speculation on why the caves were created. Both are visited by tourists on a semi-regular basis. Dorking caves have a different morphology with radon concentrations in Autumn 2016 of up to 1940 +/- 230 Bqm3. The caves in Reigate are situated along Tunnel Road. These mines were also used as air raid shelters and wine stores. They consist of an East and West system and an older cave (Barons cave) which may have a medieval origin. As the Western Caves are now a shooting range our work has been carried out in the Eastern section at Reigate. Where Dorking is concerned the shops and houses in the town have extensive interconnected cellars and galleries cut into these sands. The caves probably date from the 17th century but were used quite extensively for wine storage in the 19th century due to their constant 140C air temperatures. Real-time measurements were taken with a Durridge Rad7 with time-averaged CR39 SSNTDs being placed throughout the cave systems to assess radon distribution and compare results with the real-time detector. Both caves contain marine shallow-water deposited locking (having tensile and compressive strength) silica sands of the Cretaceous Lower Greensand Group, Folkestone Formation, with little

Long-term sand supply to Coachella Valley Fringe-toed Lizard Habitat in the Northern Coachella Valley, California

USGS Publications Warehouse

Griffiths, Peter G.; Webb, Robert H.; Lancaster, Nicholas; Kaehler, Charles A.; Lundstrom, Scott C.

2002-01-01

The Coachella Valley fringe-toed lizard (Uma inornata) is a federally listed threatened species that inhabits active sand dunes in the vicinity of Palm Springs, California. The Whitewater Floodplain and Willow Hole Reserves provide some of the primary remaining habitat for this species. The sediment-delivery system that creates these active sand dunes consists of fluvial depositional areas fed episodically by ephemeral streams. Finer fluvial sediments (typically sand size and finer) are mobilized in a largely unidirectional wind field associated with strong westerly winds through San Gorgonio Pass. The fluvial depositional areas are primarily associated with floodplains of the Whitewater?San Gorgonio Rivers and Mission Creek?Morongo Wash; other small drainages also contribute fluvial sediment to the eolian system. The eolian dunes are transitory as a result of unidirectional sand movement from the depositional areas, which are recharged with fine-grained sediment only during episodic floods that typically occur during El Ni?o years. Eolian sand moves primarily from west to east through the study area; the period of maximum eolian activity is April through June. Wind speed varies diurnally, with maximum velocities typically occurring during the afternoon. Development of alluvial fans, alteration of stream channels by channelization, in-stream gravel mining, and construction of infiltration galleries were thought to reduce the amount of fluvial sediment reaching the depositional areas upwind of Uma habitat. Also, the presence of roadways, railroads, and housing developments was thought to disrupt or redirect eolian sand movement. Most of the sediment yield to the fluvial system is generated in higher elevation areas with little or no development, and sediment yield is affected primarily by climatic fluctuations and rural land use, particularly livestock grazing and wildfire. Channelization benefits sediment delivery to the depositional plains upwind of the reserves

Differential effects of high atmospheric N and S deposition on bog plant/lichen tissue and porewater chemistry across the Athabasca Oil Sands Region

Treesearch

R. Kelman Wieder; Melanie A. Vile; Kimberli D. Scott; Cara M. Albright; Kelly J. McMillen; Dale H. Vitt; Mark E. Fenn

2016-01-01

Oil extraction and development activities in the Athabasca Oil Sands Region of northern Alberta, Canada, release NOx, SOx, and NHy to the atmosphere, ultimately resulting in increasing N and S inputs to surrounding ecosystems through atmospheric deposition. Peatlands are a major feature of the northern Alberta landscape, with bogs covering 6-10% of the land area, and...

An investigation of waste foundry sand in asphalt concrete mixtures.

PubMed

Bakis, Recep; Koyuncu, Hakan; Demirbas, Ayhan

2006-06-01

A laboratory study regarding the reuse of waste foundry sand in asphalt concrete production by replacing a certain portion of aggregate with WFS was undertaken. The results showed that replacement of 10% aggregates with waste foundry sand was found to be the most suitable for asphalt concrete mixtures. Furthermore, the chemical and physical properties of waste foundry sand were analysed in the laboratory to determine the potential effect on the environment. The results indicated that the investigated waste foundry sand did not significantly affect the environment around the deposition

Thermodynamic analysis of tar reforming through auto-thermal reforming process

DOE Office of Scientific and Technical Information (OSTI.GOV)

Nurhadi, N., E-mail: nurhadi@tekmira.esdm.go.id; Diniyati, Dahlia; Efendi, M. Ade Andriansyah

2015-12-29

Fixed bed gasification is a simple and suitable technology for small scale power generation. One of the disadvantages of this technology is producing tar. So far, tar is not utilized yet and being waste that should be treated into a more useful product. This paper presents a thermodynamic analysis of tar conversion into gas producer through non-catalytic auto-thermal reforming technology. Tar was converted into components, C, H, O, N and S, and then reacted with oxidant such as mixture of air or pure oxygen. Thus, this reaction occurred auto-thermally and reached chemical equilibrium. The sensitivity analysis resulted that the mostmore » promising process performance occurred at flow rate of air was reached 43% of stoichiometry while temperature of process is 1100°C, the addition of pure oxygen is 40% and preheating of oxidant flow is 250°C. The yield of the most promising process performance between 11.15-11.17 kmol/h and cold gas efficiency was between 73.8-73.9%.The results of this study indicated that thermodynamically the conversion of tar into producer gas through non-catalytic auto-thermal reformingis more promising.« less

Groundwater contamination by organic bases derived from coal-tar wastes

USGS Publications Warehouse

Pereira, W.E.; Rostad, C.E.; Garbarino, J.R.; Hult, M.F.

1983-01-01

A fluid sample from a shallow aquifer contaminated by coal-tar wastes was analyzed for organic bases. The sample consisted of a mixture of aqueous and oily-tar phases. The phases were separated by centrifugation and filtration. Organic bases were isolated from each phase by pH adjustment and solvent extraction. Organic bases in the oily-tar phase were further purified by neutral-alumina, micro-column adsorption chromatography. Separation and identification of the organic bases in each phase were achieved by using capillary gas chromatography-mass spectrometry-computer (GC-MS-COM) and probe distillation-high resolution mass spectrometry (PD-HRMS) techniques. Organic bases present in the aqueous phase included primary aromatic amines (such as aniline, alkylated anilines, and naphthylamines) as well as azaarenes (such as alkylated pyridines, quinolines, acridine, and benzoquinolines). The oily-tar phase contained acridine, benzacridines, dibenzacridines, and numerous other azaarenes, the elemental compositions of which were determined by PD-HRMS. Azaarenes in the oily-tar phase, varying in size from 6 to 12 rings, are reported for the first time. The origin and environmental significance of these compounds are discussed. ?? 1983.

Sand ramps as palaeoenvironmental archives: Integrating general principles and regional contexts through reanalysis of the Klipkraal Sands, South Africa

NASA Astrophysics Data System (ADS)

Rowell, Alexandra L. K.; Thomas, David S. G.; Bailey, Richard M.; Holmes, Peter J.

2018-06-01

Sand ramps occur on a continuum of topographically-controlled landforms, ranging from purely aeolian features (climbing/falling dunes) to talus cones and alluvial fans. Sand ramps have been identified as potentially important palaeoenvironmental archives in dryland regions that possess relatively few Quaternary proxy records. Their utility however requires not only good age control of depositional phases but clear identification of process regimes, determined through morphological and sedimentological analyses, with several recent studies indicating the complexities of palaeoenvironmental interpretations and the controls of ramp development (Bateman et al., 2012; Rowell et al., 2018). Klipkraal Sands is a sand ramp on the north-eastern margin of the semi-arid Karoo that has been important for inferences of the extent of southern African Late Quaternary aeolian activity (Thomas et al., 2002). We reanalyse this feature, in the light of both its significance and other recent studies that have inferred extensive southern African LGM aeolian activity (Telfer et al., 2012, 2014). New sedimentological data and twelve OSL dates indicate the Klipkraal Sands formed episodically between 100-0.14 ka, rather than accumulating rapidly, while sedimentological data question the aeolian affinities of the bulk of the feature. Therefore, Klipkraal is reinterpreted as showing no particular affinity to the LGM, with sediments locally sourced with a significant colluvial component. Only the upper historical sediments can be clearly interpreted as aeolian deposits. A complex interplay of processes is suggested, for which a meaningful palaeoenvironmental interpretation cannot be easily defined. This implies that the local geomorphic processes and controls operating on sand ramps need to be established before they can be fully utilised as palaeoenvironmental archives, with implications for their interpretation worldwide.

Deciphering structure-activity relationships in a series of Tat/TAR inhibitors.

PubMed

Pascale, Lise; González, Alejandro López; Di Giorgio, Audrey; Gaysinski, Marc; Teixido Closa, Jordi; Tejedor, Roger Estrada; Azoulay, Stéphane; Patino, Nadia

2016-11-01

A series of pentameric "Polyamide Amino Acids" (PAAs) compounds derived from the same trimeric precursor have been synthesized and investigated as HIV TAR RNA ligands, in the absence and in the presence of a Tat fragment. All PAAs bind TAR with similar sub-micromolar affinities but their ability to compete efficiently with the Tat fragment strongly differs, IC50 ranging from 35 nM to >2 μM. While NMR and CD studies reveal that all PAA interact with TAR at the same site and induce globally the same RNA conformational change upon binding, a comparative thermodynamic study of PAA/TAR equilibria highlights distinct TAR binding modes for Tat competitor and non-competitor PAAs. This led us to suggest two distinct interaction modes that have been further validated by molecular modeling studies. While the binding of Tat competitor PAAs induces a contraction at the TAR bulge region, the binding of non-competitor ones widens it. This could account for the distinct PAA ability to compete with Tat fragment. Our work illustrates how comparative thermodynamic studies of a series of RNA ligands of same chemical family are of value for understanding their binding modes and for rationalizing structure-activity relationships.

Anatomy of a shoreface sand ridge revisited using foraminifera: False Cape Shoals, Virginia/North Carolina inner shelf

USGS Publications Warehouse

Robinson, M.M.; McBride, R.A.

2008-01-01

Certain details regarding the origin and evolution of shelf sand ridges remain elusive. Knowledge of their internal stratigraphy and microfossil distribution is necessary to define the origin and to determine the processes that modify sand ridges. Fourteen vibracores from False Cape Shoal A, a well-developed shoreface-attached sand ridge on the Virginia/North Carolina inner continental shelf, were examined to document the internal stratigraphy and benthic foraminiferal assemblages, as well as to reconstruct the depositional environments recorded in down-core sediments. Seven sedimentary and foraminiferal facies correspond to the following stratigraphic units: fossiliferous silt, barren sand, clay to sandy clay, laminated and bioturbated sand, poorly sorted massive sand, fine clean sand, and poorly sorted clay to gravel. The units represent a Pleistocene estuary and shoreface, a Holocene estuary, ebb tidal delta, modern shelf, modern shoreface, and swale fill, respectively. The succession of depositional environments reflects a Pleistocene sea-level highstand and subsequent regression followed by the Holocene transgression in which barrier island/spit systems formed along the Virginia/North Carolina inner shelf ???5.2 ka and migrated landward and an ebb tidal delta that was deposited, reworked, and covered by shelf sand.

Anatomy of a shoreface sand ridge revisted using foraminifera: False Cape Shoals, Virginia/North Carolina inner shelf

USGS Publications Warehouse

Robinson, Marci M.; McBride, Randolph A.

2008-01-01

Certain details regarding the origin and evolution of shelf sand ridges remain elusive. Knowledge of their internal stratigraphy and microfossil distribution is necessary to define the origin and to determine the processes that modify sand ridges. Fourteen vibracores from False Cape Shoal A, a well-developed shoreface-attached sand ridge on the Virginia/North Carolina inner continental shelf, were examined to document the internal stratigraphy and benthic foraminiferal assemblages, as well as to reconstruct the depositional environments recorded in down-core sediments. Seven sedimentary and foraminiferal facies correspond to the following stratigraphic units: fossiliferous silt, barren sand, clay to sandy clay, laminated and bioturbated sand, poorly sorted massive sand, fine clean sand, and poorly sorted clay to gravel. The units represent a Pleistocene estuary and shoreface, a Holocene estuary, ebb tidal delta, modern shelf, modern shoreface, and swale fill, respectively. The succession of depositional environments reflects a Pleistocene sea-level highstand and subsequent regression followed by the Holocene transgression in which barrier island/spit systems formed along the Virginia/North Carolina inner shelf not, vert, ~5.2 ka and migrated landward and an ebb tidal delta that was deposited, reworked, and covered by shelf sand.

Application of fluid-rock reaction studies to in situ recovery from oil sand deposits, Alberta, Canada - I. Aqueous phase results for an experimental-statistical study of water-bitumen-shale reactions

NASA Astrophysics Data System (ADS)

Boon, J. A.; Hitchon, Brian

1983-02-01

In situ recovery operations in oil sand deposits effectively represent man-imposed low to intermediate temperature metamorphism of the sediments in the deposit. In order to evaluate some of the reactions which occur, a factorial experiment was earned out in which a shale from the Lower Cretaceous McMurray Formation in the Athabasca oil sand deposit of Alberta, in the presence or absence of bitumen, was subjected to hydrothermal treatment with aqueous fluids of varying pH and salinity, at two different temperatures, for periods up to 92 hours. The aqueous fluid was analyzed and the analytical data subjected to statistical factor analysis and analysis of variance, which enabled identification of the main processes, namely, cation exchange, the production of two types of colloidal material, and the dissolution of quartz There is also saturation of the aqueous phase by. as yet unidentified, "total organic carbon" and complete conversion and removal of all nitrogen in the shale to the aqueous phase. These reactions have implications with regards to the economics of the in situ recovery process, specifically with respect to the reuse and/or disposal of the produced water and the plugging of the pore space and hence of reduction of permeability between the injection and production wells. As a result of these experiments it is suggested that monitoring of the composition of the produced water from in situ recovery operations in oil sand deposits would be advisable.

Aviation Turbine Fuels from Tar Sands Bitumen and Heavy Oils. Part 3. Laboratory Sample Production.

DTIC Science & Technology

1987-12-01

FILD7 ar Sands, Heavy Ois Jet Fue - - - etF IE L D G R O U P S U B -G R O U P , u e -. IT - 3 seC m ) A s h l GROUP SB-RP Fue-i-T-33-A Reduced Crude...connec- tion with processes for heavy oil cracking and related catalysts. * program which allowed processing of bitumen stocks . The overall process flow

Effect of water addition in a microwave assisted thermal cracking of biomass tar gasification

NASA Astrophysics Data System (ADS)

Warsita, A.; Surya, I.

2018-02-01

Producer gas from biomass gasification is plagued by the presence of tar which causes pipe blockages. Thermal and catalytic treatments in a microwave reactor have been shown to be effective methods for removing tar from producer gas. A question arises as to the possibility of enhancing the removal mechanism by adding water into the reactor. Thermal treatment with a various amount of water was added at temperatures in the range of 800-1200°C. The tar removal efficiency obtained 96.32% at the optimum temperature of 1200°C at the water to tar ratio (W/T) of 0.3. This study shows that the removal of tar by microwave irradiation with water addition is a significant and effective method in tar cracking.

The TAR effect: when the ones who dislike become the ones who are disliked.

PubMed

Gawronski, Bertram; Walther, Eva

2008-09-01

Four studies tested whether a source's evaluations of other individuals can recursively transfer to the source, such that people who like others acquire a positive valence, whereas people who dislike others acquire a negative valence (Transfer of Attitudes Recursively; TAR). Experiment 1 provides first evidence for TAR effects, showing recursive transfers of evaluations regardless of whether participants did or did not have prior knowledge about the (dis)liking source. Experiment 2 shows that previously but not subsequently acquired knowledge about targets that were (dis)liked by a source overrode TAR effects in a manner consistent with cognitive balance. Finally, Experiments 3 and 4 demonstrate that TAR effects are mediated by higher order propositional inferences (in contrast to lower order associative processes), in that TAR effects on implicit attitude measures were fully mediated by TAR effects on explicit attitude measures. Commonalities and differences between the TAR effect and previously established phenomena are discussed.

Coal-tar based pavement sealant toxicity to freshwater macroinvertebrates.

PubMed

Bryer, Pamela J; Scoggins, Mateo; McClintock, Nancy L

2010-05-01

Non-point-source pollution is a major source of ecological impairment in urban stream systems. Recent work suggests that coal-tar pavement sealants, used extensively to protect parking areas, may be contributing a large portion of the polycyclic aromatic hydrocarbon (PAH) loading seen in urban stream sediments. The hypothesis that dried coal-tar pavement sealant flake could alter the macroinvertebrate communities native to streams in Austin, TX was tested using a controlled outdoor laboratory type approach. The treatment groups were: control, low, medium, and high with total PAH concentrations (TPAH = sum of 16 EPA priority pollutant PAHs) of 0.1, 7.5, 18.4, & 300 mg/kg respectively. The low, medium, and high treatments were created via the addition of dried coal-tar pavement sealant to a sterile soil. At the start of the 24-day exposure, sediment from a minimally impacted local reference site containing a community of live sediment-dwelling benthic macroinvertebrates was added to each replicate. An exposure-dependent response was found for several stream health measures and for several individual taxa. There were community differences in abundance (P = 0.0004) and richness (P < 0.0001) between treatments in addition to specific taxa responses, displaying a clear negative relationship with the amount of coal-tar sealant flake. These results support the hypothesis that coal-tar pavement sealants contain bioavailable PAHs that may harm aquatic environments. Copyright 2009 Elsevier Ltd. All rights reserved.

Ground-water contamination by organic bases derived from coal-tar wastes

USGS Publications Warehouse

Pereira, Wilfred E.; Rostad, Colleen E.; Garbarino, John R.; Hult, Marc F.

1983-01-01

A fluid sample from a shallow aquifer contaminated by coal-tar wastes was analyzed for organic bases. The sample consisted of a mixture of aqueous and oily-tar phases. The phases were separated by centrifugation and filtration. Organic bases were isolated from each phase by pH adjustment and solvent extraction. Organic bases in the oily-tar phase were further purified by neutral-alumina, micro-column adsorption chromatography. Separation and identification of the organic bases in each phase were achieved by using capillary gas chromatography-mass spectrometry-computer (GC-MS-COM) and probe distillation-high resolution mass spectrometry (PD-HRMS) techniques. Organic bases present in the aqueous phase included primary aromatic amines (such as aniline, alkylated anilines, and naphthylamines) as well as azaarenes (such as alkylated pyridines, quinolines, acridine, and benzoquinolines). The oily-tar phase contained acridine, benzacridines, dibenzacridines, and numerous other azaarenes, the elemental compositions of which were determined by PD-HRMS. Azaarenes in the oily-tar phase, varying in size from 6 to 12 rings, are reported for the first time. The origin and environmental significance of these compounds are discussed.

Role of TAR RNA splicing in translational regulation of simian immunodeficiency virus from rhesus macaques.

PubMed Central

Viglianti, G A; Rubinstein, E P; Graves, K L

1992-01-01

The untranslated leader sequences of rhesus macaque simian immunodeficiency virus mRNAs form a stable secondary structure, TAR. This structure can be modified by RNA splicing. In this study, the role of TAR splicing in virus replication was investigated. The proportion of viral RNAs containing a spliced TAR structure is high early after infection and decreases at later times. Moreover, proviruses containing mutations which prevent TAR splicing are significantly delayed in replication. These mutant viruses require approximately 20 days to achieve half-maximal virus production, in contrast to wild-type viruses, which require approximately 8 days. We attribute this delay to the inefficient translation of unspliced-TAR-containing mRNAs. The molecular basis for this translational effect was examined in in vitro assays. We found that spliced-TAR-containing mRNAs were translated up to 8.5 times more efficiently than were similar mRNAs containing an unspliced TAR leader. Furthermore, these spliced-TAR-containing mRNAs were more efficiently associated with ribosomes. We postulate that the level of TAR splicing provides a balance for the optimal expression of both viral proteins and genomic RNA and therefore ultimately controls the production of infectious virions. Images PMID:1629957

Eolian depositional phases during the past 50 ka and inferred climate variability for the Pampean Sand Sea, western Pampas, Argentina

NASA Astrophysics Data System (ADS)

Tripaldi, Alfonsina; Forman, Steven L.

2016-05-01

The Pampean Sand Sea, which occurs from the Argentinian Pampas to the eastern Andean piedmont, hosts presently stabilized dune fields spanning the late Quaternary. This study integrates previous results and presents new geomorphic, stratigraphic, sedimentological, and chronologic data for nineteen >2 m-thick eolian successions for the San Luis paleo-dune field, western Pampas, to better constrain the depositional history. Six eolian depositional phases are identified spanning the past 50 ka, interposed with paleosols and/or bounded by erosive surfaces. Age control was from 61 OSL ages of small aliquots of quartz grains from eolian stratigraphic units. The inferred timing of eolian phases are at ca. 70 ± 10 yr, 190 ± 20 yr, 12 to 1 ka, 22 to 17 ka, 29 to 24 ka, and 40 to 32 ka. A maximum span for periods of pedogenesis at ca. 12 to 17 ka, 22 to 24 ka, and 29 to 32 ka was provided by bounding OSL ages, which broadly overlap with high stands of pluvial lakes and glacier advances in the central Andes. We infer that the added precipitation may reflect expansion of the Southern Hemisphere monsoon, associated with Northern Hemisphere Heinrich events, leading to episodes of significantly wetter conditions (>350 mm MAP) to at least 35° S. Most of the Holocene (12 ka to 0.8 ka) was characterized by sand sheet deposit under drier than present conditions (100-450 mm MAP), associated with Monte-type vegetation (shrub steppe). The latest two eolian depositional phases, occurred at ca. 190 and 70 yr ago, during the historic period with European settlement and are related to anthropogenic landscape disturbance, though the youngest phase was concomitant with 1930s drought. Wet conditions dominated since ca. AD 1970 with new lakes and rivers forming across this eolian terrain; an incongruous environmental response in reference to drier conditions for most of the Holocene.

Selected constituents in the smoke of domestic low tar cigarettes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Griest, W. H.; Quincy, R. B.; Guerin, M. R.

Thirty-two brands of domestic commercial low tar and nicotine cigarettes were analyzed for their production of tar, nicotine, nitrogen oxides (as nitric oxide), hydrogen cyanide, acrolein, carbon monoxide and carbon dioxide under standard analytical smoking conditions. Results are compared with published data for certain brands.

The contribution of low tar cigarettes to environmental tobacco smoke

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chortyk, O.T.; Schlotzhauer, W.S.

A series of low tar cigarettes (LTC) were smoked and the quantities of condensable mainstream (inhaled) and sidestream (between puffs) smoke compounds were determined and compared to those produced by a high tar, nonfilter cigarette. It was found that the LTC produced large quantities of sidestream smoke condensates, about equal to the high tar cigarette, and contained very high levels of toxic or cocarcinogenic phenols. On an equal weight basis, the LTC emitted more of these hazardous compounds into sidestream and environmental tobacco smoke. Higher smoke yields of a flavor additive and a sugar degradation product indicated addition of suchmore » compounds during the manufacture of LTC. It was concluded that, compared to a high tar cigarette, smoking LTC may be better for the smoker, but not for the nearby nonsmoker. Information should be developed to allow smokers to choose LTC that produce lower levels of hazardous compounds in their environmentally emitted sidestream smoke.« less

Development of an ash particle deposition model considering build-up and removal mechanisms

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kjell Strandstroem; Christian Muellera; Mikko Hupa

2007-12-15

Slagging and fouling on heat exchanger surfaces in power boilers fired with fossil fuels and fuel mixtures has a significant influence on boiler efficiency and availability. Mathematical modelling has long been considered a suitable method to assist boiler operators to determine optimized operating conditions for an existing furnace. The ultimate goal in ash deposition prediction is hereby the determination of the total amount of material deposited and hence the determination of the total reduction in efficiency. Depending on the fuels fired the total deposited mass is a combination of ash particle deposition and ash particle erosion due to non-sticky particles.more » The novel ash particle deposition model presented in this work considers deposition of sticky ash particles, cleansing of deposit by non-sticky sand particles and sticking of sand due to contact with sticky ash. The steady-state modelling results for the total amount of ash deposited on the deposition probe of an entrained flow reactor presented in this work agree well with the experimental data. Only at very high fractions of sand added as non-sticky material, a significant influence of the sand on the overall mass deposited was found. Since the model considers sticking of non-sticking sand due to contact with sticky ash, the fraction of sand deposited on the probe was especially studied. Using a correction factor to consider the influence of operating time on the steady-state simulations led to good agreement between simulations and experimental data. 12 refs., 10 figs.« less

The offshore export of sand during exceptional discharge from California rivers

USGS Publications Warehouse

Warrick, Jonathan A.; Barnard, Patrick L.

2012-01-01

Littoral cells along active tectonic margins receive large inputs of sand and gravel from coastal watersheds and commonly lose this sediment to submarine canyons. One hypothesis is that the majority of coarse (sand and gravel) river sediment discharge will be emplaced within and immediately “resupply” local littoral cells. A competing hypothesis is that the infrequent, large floods that supply the majority of littoral sediment may discharge water-sediment mixtures within negatively buoyant hyperpycnal plumes that transport sediment offshore of the littoral cell. Here we summarize pre- and post-flood surveys of two wave-dominated California (United States) river deltas during record to near-record floods to help evaluate these hypotheses: the 1982–1983 delta at the San Lorenzo River mouth and the 2005 delta at the Santa Clara River mouth. Flood sedimentation at both deltas resulted in several meters of aggradation and hundreds of meters of offshore displacement of isobaths. One substantial difference between these deltas was the thick (>2 m) aggradation of sand on the inner shelf of the Santa Clara River delta that contained substantial amounts (∼50%) of littoral-grade sediment. Once deposited on the inner shelf, only a fraction (∼20%) of this river sand was observed to migrate toward the beach over the following 5 yr. Furthermore, simple hypopycnal plume behavior could not explain deposition of this sand on the inner shelf. Thus, during an exceptional flood a substantial amount of littoral-grade sand was exported offshore of the littoral system at the Santa Clara River mouth—likely from hyperpycnal plume processes—and was deposited on the inner shelf.

21 CFR 740.18 - Coal tar hair dyes posing a risk of cancer.

Code of Federal Regulations, 2012 CFR

2012-04-01

... 21 Food and Drugs 7 2012-04-01 2012-04-01 false Coal tar hair dyes posing a risk of cancer. 740.18... (CONTINUED) COSMETICS COSMETIC PRODUCT WARNING STATEMENTS Warning Statements § 740.18 Coal tar hair dyes... coal tar hair dye containing any ingredient listed in paragraph (b) of this section shall bear, in...

TAR SANDS LEACHATE STUDY

EPA Science Inventory

An inhouse research project was conducted by the EPA's Industrial Environmental Research Laboratory (IERL) at the T&E Facility in Cincinnati, Ohio, to provide information concerning the potential for release of contaminants to groundwater from in-situ and above-ground processed t...

DOE Office of Scientific and Technical Information (OSTI.GOV)

Murphey, P. C.; Daitch, D.; Environmental Science Division

In August 2005, the U.S. Congress enacted the Energy Policy Act of 2005, Public Law 109-58. In Section 369 of this Act, also known as the ''Oil Shale, Tar Sands, and Other Strategic Unconventional Fuels Act of 2005,'' Congress declared that oil shale and tar sands (and other unconventional fuels) are strategically important domestic energy resources that should be developed to reduce the nation's growing dependence on oil from politically and economically unstable foreign sources. In addition, Congress declared that both research- and commercial-scale development of oil shale and tar sands should (1) be conducted in an environmentally sound mannermore » using management practices that will minimize potential impacts, (2) occur with an emphasis on sustainability, and (3) benefit the United States while taking into account concerns of the affected states and communities. To support this declaration of policy, Congress directed the Secretary of the Interior to undertake a series of steps, several of which are directly related to the development of a commercial leasing program for oil shale and tar sands. One of these steps was the completion of a programmatic environmental impact statement (PEIS) to analyze the impacts of a commercial leasing program for oil shale and tar sands resources on public lands, with an emphasis on the most geologically prospective lands in Colorado, Utah, and Wyoming. For oil shale, the scope of the PEIS analysis includes public lands within the Green River, Washakie, Uinta, and Piceance Creek Basins. For tar sands, the scope includes Special Tar Sand Areas (STSAs) located in Utah. This paleontological resources overview report was prepared in support of the Oil Shale and Tar Sands Resource Management Plan Amendments to Address Land Use Allocations in Colorado, Utah, and Wyoming and PEIS, and it is intended to be used by Bureau of Land Management (BLM) regional paleontologists and field office staff to support future projectspecific

Connecting Brabant's cover sand landscapes through landscape history

NASA Astrophysics Data System (ADS)

Heskes, Erik; van den Ancker, Hanneke; Jungerius, Pieter Dirk; Harthoorn, Jaap; Maes, Bert; Leenders, Karel; de Jongh, Piet; Kluiving, Sjoerd; van den Oetelaar, Ger

2015-04-01

Noord-Brabant has the largest variety of cover sand landscapes in The Netherlands, and probably in Western Europe. During the Last Ice Age the area was not covered by land ice and a polar desert developed in which sand dunes buried the existing river landscapes. Some of these polar dune landscapes experienced a geomorphological and soil development that remained virtually untouched up to the present day, such as the low parabolic dunes of the Strabrechtse Heide or the later and higher dunes of the Oisterwijkse Vennen. As Noord-Brabant lies on the fringe of a tectonic basin, the thickness of cover sand deposits in the Centrale Slenk, part of a rift through Europe, amounts up to 20 metres. Cover sand deposits along the fault lines cause the special phenomenon of 'wijst' to develop, in which the higher grounds are wetter than the boarding lower grounds. Since 4000 BC humans settled in these cover sand landscapes and made use of its small-scale variety. An example are the prehistoric finds on the flanks and the historic towns on top of the 'donken' in northwest Noord-Brabant, where the cover sand landscapes are buried by river and marine deposits and only the peaks of the dunes protrude as donken. Or the church of Handel that is built beside a 'wijst' source and a site of pilgrimage since living memory. Or the 'essen' and plaggen agriculture that developed along the stream valleys of Noord-Brabant from 1300 AD onwards, giving rise to geomorphological features as 'randwallen' and plaggen soils of more than a metre thickness. Each region of Brabant each has its own approach in attracting tourists and has not yet used this common landscape history to connect, manage and promote their territories. We propose a landscape-historical approach to develop a national or European Geopark Brabants' cover sand landscapes, in which each region focuses on a specific part of the landscape history of Brabant, that stretches from the Late Weichselian polar desert when the dune

Modeling grain size variations of aeolian gypsum deposits at White Sands, New Mexico, using AVIRIS imagery

USGS Publications Warehouse

Ghrefat, H.A.; Goodell, P.C.; Hubbard, B.E.; Langford, R.P.; Aldouri, R.E.

2007-01-01

Visible and Near-Infrared (VNIR) through Short Wavelength Infrared (SWIR) (0.4-2.5????m) AVIRIS data, along with laboratory spectral measurements and analyses of field samples, were used to characterize grain size variations in aeolian gypsum deposits across barchan-transverse, parabolic, and barchan dunes at White Sands, New Mexico, USA. All field samples contained a mineralogy of ?????100% gypsum. In order to document grain size variations at White Sands, surficial gypsum samples were collected along three Transects parallel to the prevailing downwind direction. Grain size analyses were carried out on the samples by sieving them into seven size fractions ranging from 45 to 621????m, which were subjected to spectral measurements. Absorption band depths of the size fractions were determined after applying an automated continuum-removal procedure to each spectrum. Then, the relationship between absorption band depth and gypsum size fraction was established using a linear regression. Three software processing steps were carried out to measure the grain size variations of gypsum in the Dune Area using AVIRIS data. AVIRIS mapping results, field work and laboratory analysis all show that the interdune areas have lower absorption band depth values and consist of finer grained gypsum deposits. In contrast, the dune crest areas have higher absorption band depth values and consist of coarser grained gypsum deposits. Based on laboratory estimates, a representative barchan-transverse dune (Transect 1) has a mean grain size of 1.16 ??{symbol} (449????m). The error bar results show that the error ranges from - 50 to + 50????m. Mean grain size for a representative parabolic dune (Transect 2) is 1.51 ??{symbol} (352????m), and 1.52 ??{symbol} (347????m) for a representative barchan dune (Transect 3). T-test results confirm that there are differences in the grain size distributions between barchan and parabolic dunes and between interdune and dune crest areas. The t-test results

Hydrogeology of glacial deposits in a preglacial bedrock valley, Waukesha County, Wisconsin

USGS Publications Warehouse

Batten, W.G.; Conlon, T.D.

1993-01-01

Results of a 6.5-hour aquifer test indicate that the silty sand and gravel deposits have an average transmissivity of about 140 feet squared per day and an average storage coefficient of about 1.2x10"3 at one location. The horizontal hydraulic conductivity of these deposits averages about 4 feet per day. Analysis of drawdown indicates that these deposits are part of a leaky confined-aquifer system and that some water is derived from storage in an overlying clay layer. The transmissivity value determined from this aquifer test and a lack of clean sand and gravel encountered in other test holes indicate that glacial deposits at these sites may not yield enough water for a large municipal water supply. Sand and gravel deposits, capable of development as a municipal supply, may be present in the southern part of the study area. However, additional test holes are needed to determine whether adequate sand and gravel deposits underlie this area.

Understanding the stability of pyrolysis tars from biomass in a view point of free radicals.

PubMed

He, Wenjing; Liu, Qingya; Shi, Lei; Liu, Zhenyu; Ci, Donghui; Lievens, Caroline; Guo, Xiaofen; Liu, Muxin

2014-03-01

Fast pyrolysis of biomass has attracted increasing attention worldwide to produce bio-tars that can be upgraded into liquid fuels and chemicals. However, the bio-tars are usually poor in quality and stability and are difficult to be upgraded. To better understand the nature of the bio-tars, this work reveals radical concentration of tars derived from pyrolysis of two kinds of biomass. The tars were obtained by condensing the pyrolysis volatiles in 3s. It shows that the tars contain large amounts of radicals, at a level of 10(16)spins/g, and are able to generate more radicals at temperatures of 573K or higher, reaching a level of 10(19)spins/g at 673K in less than 30min. The radical generation in the tar samples is attributed to the formation of THF insoluble matters (coke), which also contain radicals. The radical concentrations of the aqueous liquids obtained in pyrolysis are also studied. Copyright © 2014 Elsevier Ltd. All rights reserved.

Catalytic Tar Reduction for Assistance in Thermal Conversion of Space Waste for Energy Production

NASA Technical Reports Server (NTRS)

Caraccio, Anne Joan; Devor, Robert William; Hintze, Paul E.; Muscatello, Anthony C.; Nur, Mononita

2014-01-01

The Trash to Gas (TtG) project investigates technologies for converting waste generated during spaceflight into various resources. One of these technologies was gasification, which employed a downdraft reactor designed and manufactured at NASA's Kennedy Space Center (KSC) for the conversion of simulated space trash to carbon dioxide. The carbon dioxide would then be converted to methane for propulsion and water for life support systems. A minor byproduct of gasification includes large hydrocarbons, also known as tars. Tars are unwanted byproducts that add contamination to the product stream, clog the reactor and cause complications in analysis instrumentation. The objective of this research was to perform reduction studies of a mock tar using select catalysts and choose the most effective for primary treatment within the KSC downdraft gasification reactor. Because the KSC reactor is operated at temperatures below typical gasification reactors, this study evaluates catalyst performance below recommended catalytic operating temperatures. The tar reduction experimentation was observed by passing a model tar vapor stream over the catalysts at similar conditions to that of the KSC reactor. Reduction in tar was determined using gas chromatography. Tar reduction efficiency and catalyst performances were evaluated at different temperatures.

Coal-tar-based pavement sealants—a potent source of PAHs

USGS Publications Warehouse

Mahler, Barbara J.; Van Metre, Peter C.

2017-01-01

P avement sealants are applied to the asphalt pavement of many parking lots, driveways, and even playgrounds in North America (Figure 1), where, when first applied, they render the pavement glossy black and looking like new. Sealant products used commercially in the central, eastern, and northern United States typically are coal-tarbased, whereas those used in the western United States typically are asphalt-based. Although the products look similar, they are chemically different. Coal-tarbased pavement sealants typically are 25-35 percent (by weight) coal tar or coal-tar pitch, materials that are known human carcinogens and that contain high concentrations of polycyclic aromatic hydrocarbons (PAHs) and related chemicals (unless otherwise noted, all Figure 1. Pavement sealant is commonly used to seal parking lots, playgrounds, and driveways throughout the United States. Sealants used in the central, northern, eastern, and southern United States typically contain coal tar or coal-tar pitch, both of which are known human carcinogens. Photos by the U.S. Geological Survey. data in this article are from Mahler et al. 2012 and references therein).

Geochemistry of radioactive elements in bituminous sands and sandstones of Permian bitumen deposits of Tatarstan (east of the Russian plate)

NASA Astrophysics Data System (ADS)

Mullakaev, A. I.; Khasanov, R. R.; Badrutdinov, O. R.; Kamaletdinov, I. R.

2018-05-01

The article investigates geochemical features of Permian (Cisuralian, Ufimian Stage and Biarmian, Kazanian Stage of the General Stratigraphic Scale of Russia) bituminous sands and sandstones located on the territory of the Volga-Ural oil and gas province (Republic of Tatarstan). Natural bitumens are extracted using thermal methods as deposits of high-viscosity oils. In the samples studied, the specific activity of natural radionuclides from the 238U (226Ra), 232Th, and 40K series was measured using gamma spectrometry. As a result of the precipitation of uranium and thorium and their subsequent decay, the accumulation of radium (226Ra and 228Ra) has been shown to occur in the bituminous substance. In the process of exploitation of bitumen-bearing rock deposits (as an oil fields) radium in the composition of a water-oil mixture can be extracted to the surface or deposited on sulfate barriers, while being concentrated on the walls of pipes and other equipment. This process requires increased attention to monitoring and inspection the environmental safety of the exploitation procedure.

Implications of Use of Coal-Tar-Based Pavement Sealcoat on Urban Water Quality

NASA Astrophysics Data System (ADS)

Van Metre, P. C.

2015-12-01

Coal-tar-based (CT) sealcoat is used to protect and improve the appearance of asphalt pavement of driveways and parking lots primarily in the central and eastern U.S. and in Canada. CT sealcoat typically is 20 to 35% crude coal tar or coal-tar pitch and contains from 50,000 to 100,000 mg/kg polycyclic aromatic hydrocarbons (PAH), about 1,000 times more than asphalt-based (AS) sealcoat or asphalt itself. Tires and snowplows abrade the friable sealcoat surface into fine particles—median total PAH concentrations in dust from CT-sealcoated pavement are 2,200 mg/kg compared to a median concentration of 11 mg/kg for dust from unsealed pavement. Use of CT sealcoat has several implications for urban streams and lakes. Source apportionment modeling has indicated that, in regions where CT sealcoat is prevalent, particles from sealcoated pavement are contributing the majority of the PAHs to recently deposited lake sediment, often resulting in sediment concentrations above toxicity thresholds based on effects-based sediment quality guidelines. Acute 2-day laboratory toxicity testing of simulated runoff from CT-sealcoated pavement to a cladoceran (Ceriodaphnia dubia) and fathead minnows (Pimephales promelas) demonstrated that toxicity continues for samples collected for weeks or months following sealcoat application and that toxicity is enhanced by exposure to UV light. Using the fish-liver cell line RTL-W1, runoff collected as much as 36 days following CT-sealcoat application has been demonstrated to cause DNA damage and impair DNA repair capacity. These results demonstrate that CT runoff is a potential hazard to aquatic ecosystems and that exposure to sunlight can enhance toxicity and genetic damage. Recent research has provided direct evidence that restricting use of CT sealcoat in a watershed can lead to a substantial reduction in PAH concentrations in receiving water bodies.

Provenance of aeolian sands in the Hetao Plain, northwestern China

NASA Astrophysics Data System (ADS)

Yang, Xingchen; Cai, Maotang; Ye, Peisheng; Ye, Mengni; Li, Chenglu; Wu, Hang; Lu, Jing; Wang, Tao; Zhao, Zhirong; Luzhou, Yangfan; Liu, Chao

2018-06-01

Patches of aeolian sand are distributed throughout the Hetao Plain, which pose threats to farming and agriculture. Identification of the provenance of the aeolian sands may help with efforts to alleviate ecological stress in Inner Mongolia and in the paleoenvironmental interpretation of sandy sequences. This study uses geochemical data to determine the provenance of aeolian sands from the Hetao Plain. Provenance discrimination diagrams revealed that the aeolian sands were mainly derived from mixed source felsic granites and granodiorites, which have undergone weak sedimentary recycling. The chemical index of alteration and A-CN-K data indicated that the aeolian sediments were transported over a short distance. Comparison of trace element and rare earth element (REE) ratios of the aeolian sands with rock samples from potential source areas has revealed that aeolian sand deposits in the Hetao Plain were mainly derived from Sertengshan and Yellow River sediments. The Langshan and Ordos Plateau may represent additional sand sources for the Hetao Plain.

Wet scrubbing of biomass producer gas tars using vegetable oil

NASA Astrophysics Data System (ADS)

Bhoi, Prakashbhai Ramabhai

The overall aims of this research study were to generate novel design data and to develop an equilibrium stage-based thermodynamic model of a vegetable oil based wet scrubbing system for the removal of model tar compounds (benzene, toluene and ethylbenzene) found in biomass producer gas. The specific objectives were to design, fabricate and evaluate a vegetable oil based wet scrubbing system and to optimize the design and operating variables; i.e., packed bed height, vegetable oil type, solvent temperature, and solvent flow rate. The experimental wet packed bed scrubbing system includes a liquid distributor specifically designed to distribute a high viscous vegetable oil uniformly and a mixing section, which was designed to generate a desired concentration of tar compounds in a simulated air stream. A method and calibration protocol of gas chromatography/mass spectroscopy was developed to quantify tar compounds. Experimental data were analyzed statistically using analysis of variance (ANOVA) procedure. Statistical analysis showed that both soybean and canola oils are potential solvents, providing comparable removal efficiency of tar compounds. The experimental height equivalent to a theoretical plate (HETP) was determined as 0.11 m for vegetable oil based scrubbing system. Packed bed height and solvent temperature had highly significant effect (p0.05) effect on the removal of model tar compounds. The packing specific constants, Ch and CP,0, for the Billet and Schultes pressure drop correlation were determined as 2.52 and 2.93, respectively. The equilibrium stage based thermodynamic model predicted the removal efficiency of model tar compounds in the range of 1-6%, 1-4% and 1-2% of experimental data for benzene, toluene and ethylbenzene, respectively, for the solvent temperature of 30° C. The NRTL-PR property model and UNIFAC for estimating binary interaction parameters are recommended for modeling absorption of tar compounds in vegetable oils. Bench scale

Acid Tar Lagoons: Management and Recovery

NASA Astrophysics Data System (ADS)

Bohers, Anna; Hroncová, Emília; Ladomerský, Juraj

2017-04-01

This contribution presents the issue with possibility of definitive removal of dangerous environmental burden in Slovakia - serious historical problem of two acid tar lagoons. In relation to their removal, no technology has been found so far - technologically and economically suitable, what caused problems with its management. Locality Predajná is well known in Slovakia by its character of contrasts: it is situated in the picturesque landscape of National Park buffer zone of Nízke Tatry, on the other site it is contaminated by 229 211m3 of acid tar with its characteristics of toxicity, carcinogenicity, teratogenicity, mutagenicity and toxicity especially for animals and plants. Acid tar in two landfills with depth of 1m in case of the first lagoon and 9,5m in case of the second lagoon is a waste product derived from operation of Petrochema Dubová - refinery and petrochemical plant whose activity was to process the crude oil through processes of sulfonation and adsorption technology for producing lubricating and special oils, synthetic detergents and special white oils for cosmetic and medical purposes. A part of acid tar was incinerated in two incineration plats. Concentration of SO2 in combustion gases was too high and it was not possible to decrease it under the value of 2000 mg.mn-3 [LADOMERSKÝ, J. - SAMEŠOVÁ, D.: Reduction in sulfur dioxide emissions waste gases of incineration plant. Acta facultatis ecologiae. 1999, p. 217-223]. That is why it was necessary to put them out of operation. Later, because of public opposition it was not possible to build a new incineration plat corresponding to the state of the art. Even though actual Slovak and European legislative for protection of environment against such impacts, neither of tried methods - bio or non-biologic treatment methods - was proved as suitable for processing or for recovery in the reason of different factors admission: i.e. strong aggressivity, difficulty with handling because of its sludgy and

Porous Carbon Nanofibers from Electrospun Biomass Tar/Polyacrylonitrile/Silver Hybrids as Antimicrobial Materials.

PubMed

Song, Kunlin; Wu, Qinglin; Zhang, Zhen; Ren, Suxia; Lei, Tingzhou; Negulescu, Ioan I; Zhang, Quanguo

2015-07-15

A novel route to fabricate low-cost porous carbon nanofibers (CNFs) using biomass tar, polyacrylonitrile (PAN), and silver nanoparticles has been demonstrated through electrospinning and subsequent stabilization and carbonization processes. The continuous electrospun nanofibers had average diameters ranging from 392 to 903 nm. The addition of biomass tar resulted in increased fiber diameters, reduced thermal stabilities, and slowed cyclization reactions of PAN in the as-spun nanofibers. After stabilization and carbonization, the resultant CNFs showed more uniformly sized and reduced average diameters (226-507 nm) compared to as-spun nanofibers. The CNFs exhibited high specific surface area (>400 m(2)/g) and microporosity, attributed to the combined effects of phase separations of the tar and PAN and thermal decompositions of tar components. These pore characteristics increased the exposures and contacts of silver nanoparticles to the bacteria including Gram-positive Staphylococcus aureus and Gram-negative Escherichia coli, leading to excellent antimicrobial performances of as-spun nanofibers and CNFs. A new strategy is thus provided for utilizing biomass tar as a low-cost precursor to prepare functional CNFs and reduce environmental pollutions associated with direct disposal of tar as an industrial waste.

Estimating tar and nicotine exposure: human smoking versus machine generated smoke yields.

PubMed

St Charles, F K; Kabbani, A A; Borgerding, M F

2010-02-01

Determine human smoked (HS) cigarette yields of tar and nicotine for smokers using their own brand in their everyday environment. A robust, filter analysis method was used to estimate the tar and nicotine yields for 784 subjects. Seventeen brands were chosen to represent a wide range of styles: 85 and 100 mm lengths; menthol and non-menthol; 17, 23, and 25 mm circumference; with tar yields [Federal Trade Commission (FTC) method] ranging from 1 to 18 mg. Tar bands chosen corresponded to yields of 1-3 mg, 4-6 mg, 7-12 mg, and 13+ mg. A significant difference (p<0.0001) in HS yields of tar and nicotine between tar bands was found. Machine-smoked yields were reasonable predictors of the HS yields for groups of subjects, but the relationship was neither exact nor linear. Neither the FTC, the Massachusetts (MA) nor the Canadian Intensive (CI) machine-smoking methods accurately reflect the HS yields across all brands. The FTC method was closest for the 7-12 mg and 13+ mg products and the MA method was closest for the 1-3mg products. The HS yields for the 4-6 mg products were approximately midway between the FTC and the MA yields. HS nicotine yields corresponded well with published urinary and plasma nicotine biomarker studies. 2009 Elsevier Inc. All rights reserved.

Timing and petroleum sources for the Lower Cretaceous Mannville Group oil sands of northern Alberta based on 4-D modeling

USGS Publications Warehouse

Higley, D.K.; Lewan, M.D.; Roberts, L.N.R.; Henry, M.

2009-01-01

The Lower Cretaceous Mannville Group oil sands of northern Alberta have an estimated 270.3 billion m3 (BCM) (1700 billion bbl) of in-place heavy oil and tar. Our study area includes oil sand accumulations and downdip areas that partially extend into the deformation zone in western Alberta. The oil sands are composed of highly biodegraded oil and tar, collectively referred to as bitumen, whose source remains controversial. This is addressed in our study with a four-dimensional (4-D) petroleum system model. The modeled primary trap for generated and migrated oil is subtle structures. A probable seal for the oil sands was a gradual updip removal of the lighter hydrocarbon fractions as migrated oil was progressively biodegraded. This is hypothetical because the modeling software did not include seals resulting from the biodegradation of oil. Although the 4-D model shows that source rocks ranging from the Devonian-Mississippian Exshaw Formation to the Lower Cretaceous Mannville Group coals and Ostracode-zone-contributed oil to Mannville Group reservoirs, source rocks in the Jurassic Fernie Group (Gordondale Member and Poker Chip A shale) were the initial and major contributors. Kinetics associated with the type IIS kerogen in Fernie Group source rocks resulted in the early generation and expulsion of oil, as early as 85 Ma and prior to the generation from the type II kerogen of deeper and older source rocks. The modeled 50% peak transformation to oil was reached about 75 Ma for the Gordondale Member and Poker Chip A shale near the west margin of the study area, and prior to onset about 65 Ma from other source rocks. This early petroleum generation from the Fernie Group source rocks resulted in large volumes of generated oil, and prior to the Laramide uplift and onset of erosion (???58 Ma), which curtailed oil generation from all source rocks. Oil generation from all source rocks ended by 40 Ma. Although the modeled study area did not include possible western

29 CFR 1926.1102 - Coal tar pitch volatiles; interpretation of term.

Code of Federal Regulations, 2014 CFR

2014-07-01

... 29 Labor 8 2014-07-01 2014-07-01 false Coal tar pitch volatiles; interpretation of term. 1926.1102 Section 1926.1102 Labor Regulations Relating to Labor (Continued) OCCUPATIONAL SAFETY AND HEALTH... Hazardous Substances § 1926.1102 Coal tar pitch volatiles; interpretation of term. Note: The requirements...

29 CFR 1926.1102 - Coal tar pitch volatiles; interpretation of term.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 29 Labor 8 2011-07-01 2011-07-01 false Coal tar pitch volatiles; interpretation of term. 1926.1102 Section 1926.1102 Labor Regulations Relating to Labor (Continued) OCCUPATIONAL SAFETY AND HEALTH... Hazardous Substances § 1926.1102 Coal tar pitch volatiles; interpretation of term. Note: The requirements...

29 CFR 1926.1102 - Coal tar pitch volatiles; interpretation of term.

Code of Federal Regulations, 2012 CFR

2012-07-01

... 29 Labor 8 2012-07-01 2012-07-01 false Coal tar pitch volatiles; interpretation of term. 1926.1102 Section 1926.1102 Labor Regulations Relating to Labor (Continued) OCCUPATIONAL SAFETY AND HEALTH... Hazardous Substances § 1926.1102 Coal tar pitch volatiles; interpretation of term. Note: The requirements...

29 CFR 1926.1102 - Coal tar pitch volatiles; interpretation of term.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 29 Labor 8 2010-07-01 2010-07-01 false Coal tar pitch volatiles; interpretation of term. 1926.1102 Section 1926.1102 Labor Regulations Relating to Labor (Continued) OCCUPATIONAL SAFETY AND HEALTH... Hazardous Substances § 1926.1102 Coal tar pitch volatiles; interpretation of term. Note: The requirements...

Exploring how sand ramps respond to Quaternary environmental change in Southern Africa

NASA Astrophysics Data System (ADS)

Rowell, Alex; Thomas, David; Bailey, Richard

2014-05-01

The current climate of southern Africa is particularly complex and interesting due to the interaction of several climatic systems. However, reconstructions of how these systems behaved in the past, and how the environment responded, have been hampered by a general paucity of records and poor chronological control. Sand ramps may provide the potential to improve palaeoenvironmental reconstructions of southern Africa (and beyond). Formed against a topographic barrier, sand ramps include a combination of aeolian, fluvial and colluvial deposits in varying proportions. Therefore, they have the potential to record changes in moisture availability, circulation patterns and sediment supply which can be independently dated using luminescence dating. Nevertheless relatively little attention has been paid to these features and thus the environmental controls on their formation are not yet fully understood. In particular, there is debate as to whether they reflect deposition during a 'window of opportunity' in which high-magnitude, low-frequency events are recorded (Bateman et al. 2012) or whether they record more gradual, cyclic climate change (Bertram, 2003) or even if there is a uniform control on their formation. This research aims to investigate how sand ramps respond to environmental change and what they can tell us about the paleoenvironment of southern Africa. This poster displays preliminary results based on initial field investigation. This confirmed sand ramps to be ubiquitous in southern Africa and that they record a complex interaction of aeolian, fluvial and colluvial deposits which appears to differ between sand ramps. Preliminary luminescence dating results and sedimentology are displayed for two sand ramps, one from south west Namibia the other from the Karoo region of South Africa.

A search for aquifers of sand and gravel by electrical-resistivity methods in north-central New Castle County, Delaware

USGS Publications Warehouse

Spicer, H. Cecil; McCullough, Richard A.; Mack, Frederick K.

1955-01-01

A search for aquifers in an area immediately north of the Chesapeake and Delaware Canal in New Castle, Del., has been made by an electrical resistivity study.  The search located 32 sites that may be underlain by sand and gravel. The thicker deposits are significant with respect to the occurrence of ground water, and all of them are of interest as possible sources of sand and gravel for construction purposes, such as for highway construction.  The thickness of these deposits ranges from 4.4 feet to 77 feet, and the computed resistivity for these ranges from a low of 97,800 ohm-cms to a high of 423,800 ohm-cms.  The study located with certainty one buried channel filled with sand and gravel deposits and pointed out the possibility of others that may be aquifers.  The interpretations show that a large deposit of sand and gravel is present in the eastern part of the area investigated and it is tentatively assumed that this deposit is continuous and may yield large quantities of ground water.  Places where the deposit was found to be the thickest and of high resistivity are described.

Task 3.9 -- Catalytic tar cracking. Semi-annual report, January 1--June 30, 1995

DOE Office of Scientific and Technical Information (OSTI.GOV)

Young, B.C.; Timpe, R.C.

1995-12-31

Tar produced in the gasification of coal is deleterious to the operation of downstream equipment including fuel cells, gas turbines, hot-gas stream cleanup filters, and pressure swing adsorption systems. Catalytic cracking of tars to smaller hydrocarbons can be an effective means to remove these tars from gas streams and, in the process, generate useful products, e.g., methane gas, which is crucial to the operation of molten carbonate fuel cells. The objectives of this project are to investigate whether gasification tars can be cracked by synthetic nickel-substituted micamontmorillonite, zeolite, or dolomite material; and whether the tars can be cracked selectively bymore » these catalysts to produce a desired liquid and/or gas stream. Results to date are presented in the cited papers.« less

Microwave-induced cracking of pyrolytic tars coupled to microwave pyrolysis for syngas production.

PubMed

Beneroso, D; Bermúdez, J M; Montes-Morán, M A; Arenillas, A; Menéndez, J A

2016-10-01

Herein a new process is proposed to produce a syngas-rich gas fraction (>80vol% H2+CO) from biowaste based on microwave heating within two differentiated steps in order to avoid tars production. The first step consists of the microwave pyrolysis of biowaste induced by a char-based susceptor at 400-800°C; tars, char and syngas-rich gas fractions being produced. The tars are then fed into the second step where a portion of the char from the first step is used as a bed material in a 0.3:1wt% ratio. This bed is heated up by microwaves up to 800°C, allowing thermal cracking of tars and additional syngas (>90vol% H2+CO) being then produced. This new concept arises as an alternative technology to the gasification of biowastes for producing syngas with no need for catalysts or gasifying reagents to minimise tars production. Copyright © 2016 Elsevier Ltd. All rights reserved.

29 CFR 1915.1002 - Coal tar pitch volatiles; interpretation of term.

Code of Federal Regulations, 2014 CFR

2014-07-01

... 29 Labor 7 2014-07-01 2014-07-01 false Coal tar pitch volatiles; interpretation of term. 1915.1002 Section 1915.1002 Labor Regulations Relating to Labor (Continued) OCCUPATIONAL SAFETY AND HEALTH... Toxic and Hazardous Substances § 1915.1002 Coal tar pitch volatiles; interpretation of term. Note: The...

29 CFR 1915.1002 - Coal tar pitch volatiles; interpretation of term.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 29 Labor 7 2011-07-01 2011-07-01 false Coal tar pitch volatiles; interpretation of term. 1915.1002 Section 1915.1002 Labor Regulations Relating to Labor (Continued) OCCUPATIONAL SAFETY AND HEALTH... Toxic and Hazardous Substances § 1915.1002 Coal tar pitch volatiles; interpretation of term. Note: The...

29 CFR 1915.1002 - Coal tar pitch volatiles; interpretation of term.

Code of Federal Regulations, 2013 CFR

2013-07-01

... 29 Labor 7 2013-07-01 2013-07-01 false Coal tar pitch volatiles; interpretation of term. 1915.1002 Section 1915.1002 Labor Regulations Relating to Labor (Continued) OCCUPATIONAL SAFETY AND HEALTH... Toxic and Hazardous Substances § 1915.1002 Coal tar pitch volatiles; interpretation of term. Note: The...

29 CFR 1915.1002 - Coal tar pitch volatiles; interpretation of term.

Code of Federal Regulations, 2012 CFR

2012-07-01

... 29 Labor 7 2012-07-01 2012-07-01 false Coal tar pitch volatiles; interpretation of term. 1915.1002 Section 1915.1002 Labor Regulations Relating to Labor (Continued) OCCUPATIONAL SAFETY AND HEALTH... Toxic and Hazardous Substances § 1915.1002 Coal tar pitch volatiles; interpretation of term. Note: The...

29 CFR 1915.1002 - Coal tar pitch volatiles; interpretation of term.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 29 Labor 7 2010-07-01 2010-07-01 false Coal tar pitch volatiles; interpretation of term. 1915.1002 Section 1915.1002 Labor Regulations Relating to Labor (Continued) OCCUPATIONAL SAFETY AND HEALTH... Toxic and Hazardous Substances § 1915.1002 Coal tar pitch volatiles; interpretation of term. Note: The...

Enhanced Column Filtration for Arsenic Removal from Water: Polymer-Templated Iron Oxide Nanoparticles Immobilized on Sand via Layer-by-Layer Deposition

NASA Astrophysics Data System (ADS)

Cheng, Calvin Chia-Hung

Arsenic is ubiquitous in water sources around the world and is highly toxic. While precipitation and membrane filtration techniques are successfully implemented in developed cities, they are unsuitable for rural and low-resource settings lacking centralized facilities. This thesis presents the use of ultra-small iron oxide (Fe2O3) nanoparticles functionalized on sand granules for use as a house-hold scale adsorption filter. Water-stable alpha-Fe2O3 (hematite) nanoparticles (<10 nm) were synthesized via a collapsed-polymer approach using poly(acrylic acid) and Fe3+ ions. The nanoparticles exhibited high arsenic adsorption, with 147 +/- 2 mg As(III) per g Fe2O3 and 91 +/- 10 mg As(V) per g Fe2O3. The platform was also used to synthesize iron-based composites, including magnetite (Fe 3O4) and Fe-Cu oxide nanoparticles. For use as a column filter, Fe2O3-PAA nanoparticles were functionalized on sand granules using a layer-by-layer deposition method, with the nanoparticles embedded in the negative layer. The removal of As(III) by the Fe2O 3-PAA functionalized column was described by reversible 1st order kinetics where the forward and reverse rate constants were 0.31 hr -1 and 0.097 hr-1, respectively. Implemented as a passive water filter with 30 x 30 x 50 cm3 dimensions, the filter has an expected lifetime in the order of many years. By controlling the flow rate of the column depending on contamination levels, the filter effectively removes arsenic down to the safety limit of 0.01 mg/L. In a parallel project, the layer-by-layer deposition of Poly(diallydimethyl ammonium chloride) (PDDA) and poly(sodium 5-styrenesulfonate) (PSS) was exploited for a highly practical synthesis of discrete gradient surfaces. By independently controlling the concentration of NaCl in PDDA and PSS deposition solutions, a 2-dimensional matrix of surfaces was created in 96-well microtiter plates. Distinct non-monotonic dye adsorption patterns on the gradient surfaces was observed. Practical

Risk Assessment for Children Exposed to Beach Sands Impacted by Oil Spill Chemicals.

PubMed

Black, Jennifer C; Welday, Jennifer N; Buckley, Brian; Ferguson, Alesia; Gurian, Patrick L; Mena, Kristina D; Yang, Ill; McCandlish, Elizabeth; Solo-Gabriele, Helena M

2016-08-27

Due to changes in the drilling industry, oil spills are impacting large expanses of coastlines, thereby increasing the potential for people to come in contact with oil spill chemicals. The objective of this manuscript was to evaluate the health risk to children who potentially contact beach sands impacted by oil spill chemicals from the Deepwater Horizon disaster. To identify chemicals of concern, the U.S. Environmental Protection Agency's (EPA's) monitoring data collected during and immediately after the spill were evaluated. This dataset was supplemented with measurements from beach sands and tar balls collected five years after the spill. Of interest is that metals in the sediments were observed at similar levels between the two sampling periods; some differences were observed for metals levels in tar balls. Although PAHs were not observed five years later, there is evidence of weathered-oil oxidative by-products. Comparing chemical concentration data to baseline soil risk levels, three metals (As, Ba, and V) and four PAHs (benzo[a]pyrene, benz[a]anthracene, benzo[b]fluoranthene, and dibenz[a,h]anthracene) were found to exceed guideline levels prompting a risk assessment. For acute or sub-chronic exposures, hazard quotients, computed by estimating average expected contact behavior, showed no adverse potential health effects. For cancer, computations using 95% upper confidence limits for contaminant concentrations showed extremely low increased risk in the 10(-6) range for oral and dermal exposure from arsenic in sediments and from dermal exposure from benzo[a]pyrene and benz[a]anthracene in weathered oil. Overall, results suggest that health risks are extremely low, given the limitations of available data. Limitations of this study are associated with the lack of toxicological data for dispersants and oil-spill degradation products. We also recommend studies to collect quantitative information about children's beach play habits, which are necessary to more

Porous media grain size distribution and hydrodynamic forces effects on transport and deposition of suspended particles.

PubMed

Ahfir, Nasre-Dine; Hammadi, Ahmed; Alem, Abdellah; Wang, HuaQing; Le Bras, Gilbert; Ouahbi, Tariq

2017-03-01

The effects of porous media grain size distribution on the transport and deposition of polydisperse suspended particles under different flow velocities were investigated. Selected Kaolinite particles (2-30μm) and Fluorescein (dissolved tracer) were injected in the porous media by step input injection technique. Three sands filled columns were used: Fine sand, Coarse sand, and a third sand (Mixture) obtained by mixing the two last sands in equal weight proportion. The porous media performance on the particle removal was evaluated by analysing particles breakthrough curves, hydro-dispersive parameters determined using the analytical solution of convection-dispersion equation with a first order deposition kinetics, particles deposition profiles, and particle-size distribution of the recovered and the deposited particles. The deposition kinetics and the longitudinal hydrodynamic dispersion coefficients are controlled by the porous media grain size distribution. Mixture sand is more dispersive than Fine and Coarse sands. More the uniformity coefficient of the porous medium is large, higher is the filtration efficiency. At low velocities, porous media capture all sizes of suspended particles injected with larger ones mainly captured at the entrance. A high flow velocity carries the particles deeper into the porous media, producing more gradual changes in the deposition profile. The median diameter of the deposited particles at different depth increases with flow velocity. The large grain size distribution leads to build narrow pores enhancing the deposition of the particles by straining. Copyright © 2016. Published by Elsevier B.V.

Microbial metabolism alters pore water chemistry and increases consolidation of oil sands tailings.

PubMed

Arkell, Nicholas; Kuznetsov, Petr; Kuznetsova, Alsu; Foght, Julia M; Siddique, Tariq

2015-01-01

Tailings produced during bitumen extraction from surface-mined oil sands ores (tar sands) comprise an aqueous suspension of clay particles that remain dispersed for decades in tailings ponds. Slow consolidation of the clays hinders water recovery for reuse and retards volume reduction, thereby increasing the environmental footprint of tailings ponds. We investigated mechanisms of tailings consolidation and revealed that indigenous anaerobic microorganisms altered porewater chemistry by producing CO and CH during metabolism of acetate added as a labile carbon amendment. Entrapped biogenic CO decreased tailings pH, thereby increasing calcium (Ca) and magnesium (Mg) cations and bicarbonate (HCO) concentrations in the porewater through dissolution of carbonate minerals. Soluble ions increased the porewater ionic strength, which, with higher exchangeable Ca and Mg, decreased the diffuse double layer of clays and increased consolidation of tailings compared with unamended tailings in which little microbial activity was observed. These results are relevant to effective tailings pond management strategies. Copyright © by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America, Inc.

The sand-deposition impact of artificial gravel beds on the protection of the Mogao Grottoes

PubMed Central

Li, Guo Shuai; Qu, Jian Jun; Li, Xu Zhi; Wang, Wan Fu

2014-01-01

Gravel beds can prevent sand-dust emission and weaken sand-dust flux. We used wind-tunnel experiments and field observations on artificial gravel beds above the Mogao Grottoes to quantify their impact. In the report, we identified a significant correlation between gravel roughness and its ability to trap wind-transported sand. The optimal combinations of gravel diameter and coverage were determined. The greatest roughness is achieved when small gravel coverage is 75%, medium 40% and large 45%. We found that initial wind speed and gravel coverage are the key factors controlling the amount of sand trapped by the gravel beds. PMID:24614183

Drivers of drift sand dynamics; a reconstruction for the Wekeromse Zand, the Netherlands

NASA Astrophysics Data System (ADS)

Hendriks, Chantal; Sonneveld, Marthijn; Wallinga, Jakob

2013-04-01

Inland active drift sand landscapes are regarded as unique ecosystems of great historical and geomorphological value. Recent studies have highlighted the role of multiple factors in the initiation and stabilization of drift sand landscapes. To unravel the importance of different forcings (e.g. agricultural practices, climate) and their interplay, insight in the chronology of drift sand dynamics is essential. In this study, we aimed to reconstruct the dynamics of the drift sand landscape of the Wekeromse Zand (central Netherlands) and to develop a conceptual model to understand the processes involved. The Wekeromse Zand study area (370 ha) is located on the border of a central push moraine and is characterised by open active drift sands (14 ha) and vegetated hills and valleys. The surroundings are dominated by modern agricultural practices, and remnants from ancient iron age Celtic Field systems showing that the area has been in agricultural use since at least the Iron Age. For the study area we: i) analysed historical maps going back to the early 19th century, ii) performed a field survey to map the palaeolandscape (before drift sand activation) and iii) employed optically stimulated luminescence (OSL) dating of drift sand deposits on 11 samples from two locations to determine the timing of drift sand deposition. Analysis of the available topographic maps showed no substantial aeolean activity of the area outside its morphological boundaries. OSL dating revealed that two drift sand layers were deposited between 1373 and 1462 AD and between 1680 and 1780 AD. A layer with a higher organic matter content was found at one of the sites. This suggests that the Wekeromse Zand has known three relatively stable periods: i) a period between the start of the Holocene to the Late Medieval Period, ii) in between the Medieval climatic optimum and the climatic Maunder minimum, and iii) current situation. Despite the fact that agricultural activities occurred in this area from the

Dust deposits on Mars: The 'parna' analog

NASA Technical Reports Server (NTRS)

Greeley, Ronald; Williams, Steven H.

1994-01-01

Parna is an Autralian aboriginal word meaning 'sandy dust'. It has been applied to deposits of clay, silt, and sand which were initially transported by the wind as aggregates, or pellets, of sand size. Parna is distinguished by its silt and clay content, which in some cases exceeds 85% of the total volume of the deposit. Much of the fine-grained playa silt and clay is incorporated into the parna as sand-sized aggregates, which greatly facilitate their transportation and reworking by the wind. Rain following aggregate emplacement can cause their disintegration, rendering the parna immobile by the wind, yet some pellets can survive several wetting/drying episodes. Parna deposits on Earth occur both as dune forms and as sheet deposits which mantle older terrains. In both cases the deposits are typically derived from lacustrine (lake) beds, such as playas. There is substantial evidence to suggest that bodies of water existed on Mars in the past. Thus, the potential is high for lacustrine deposits and the formation of parna on Mars. Although no parna dunes have been identified, it is suggested that the deposits derived from White Rock (-8 deg, 335 deg W), near Mamers Valles (34 deg, 343 deg W), and elsewhere on Mars may represent sheet parna. Data obtained from Mars-94/96 missions and potential landed spacecraft may provide additional evidence for the existence of parna on Mars.

Petrogenic organic carbon and PAHs in snow deposited on Athabasca oil sands region lakes

NASA Astrophysics Data System (ADS)

Ahad, J. M.; Pakdel, H.; Gammon, P. R.; Savard, M. M.

2017-12-01

Fugitive dust associated with surface mining activities is one of the principal vectors for transport of airborne contaminants in Canada's Athabasca oil sands (AOS) region. The two main sources for mining-related dust - unprocessed oil sand and petroleum coke (petcoke) - contain high levels of bitumen-derived organic contaminants such as polycyclic aromatic hydrocarbons (PAHs). Here, we report the radiocarbon (14C) contents of solvent-extractable organics in snow particulates deposited during the winter of 2016-17 on fourteen lakes across the AOS region to quantify the contribution of anthropogenic dust transported directly to these ecosystems. Concentrations of parent and alkylated PAHs were determined in both dissolved and particulate fractions of snow. Radiocarbon isotope ratios (Δ14C) ranged from -805 to -177‰, indicating a significant contribution of petrogenic or fossil (i.e., Δ14C = -1000‰) carbon in snowpack dust at some sites. More negative Δ14C values were generally found in samples containing higher levels of particulate matter and at lakes closer to the geographic center of AOS mining operations. Concentrations of PAHs > 2 rings were significantly higher in the particulate phase and in samples with the largest petrogenic carbon components. Relatively high levels of PAHs at some distal sites associated with less negative Δ14C values pointed to an important modern carbon contribution, potentially ash originating from the 1.5 million acre 2016 Fort McMurray wildfire. As demonstrated here, fugitive dust in snow covering AOS region lakes can contain significant petrogenic organic carbon and high levels of PAHs, particularly in areas close (i.e., < 25 km) to the center of AOS mining operations. The spring snowmelt thus provides a direct pathway for mining-related contaminants to lake sediments.

Stratigraphic framework of inner shelf storm-dominated sand ridges, Alabama EEZ: Implications for sequence stratigraphy, global climate change, and petroleum exploration

DOE Office of Scientific and Technical Information (OSTI.GOV)

Davies, D.J.; Parker, S.J.

The Alabama exclusive economic zone (EEZ) contains an abundance of orthoquartzitic shelf sand ridges elongate northwest-southeast diagonally from the shoreline. Soft-sediment peels from 59 Vibracores[sup TM] from the Alabama inner shelf permit detailed description of sand ridge sedimentary structures, fabrics, and eight sea-floor sediment types. These overlie the pre-Holocene sequence boundary and lower Holocene transgressive sediments. In general, the ridges are capped by coarse stacked graded shelly sands, echinoid sands, and clean sands deposited well above storm wave base. The graded shelly sand microfacies, the most common sediment type, is inferred to represent shelf storm deposits because of its gradedmore » nature, sharp base, and variable thickness (0.1 to 4 m). Considerable patchiness of facies is found on a single sand ridge. The facies patchiness may result from the interplay between relict sediment distribution, present hydrodynamics and local difference in preserved shell content. Due to the microtidal regime of the Alabama EEZ and the prevalence of the graded sands on the ridge crests, the ridges are interpreted to be dominantly storm-wave in origin. This type of coarse, clean sandy deposit is a poorly studied yet important possible model for many shelf-sand petroleum reservoirs.« less

Texture and depositional history of near-surface alluvial deposits in the central part of the western San Joaquin Valley, California

USGS Publications Warehouse

Laudon, Julie; Belitz, Kenneth

1989-01-01

Saline conditions and associated high levels of selenium and other soluble trace elements in soil, shallow ground water, and agricultural drain water of the western San Joaquin Valley, California, have prompted a study of the texture of near-surface alluvial deposits in the central part of the western valley. Texture is characterized by the percentage of coarse-grained sediment present within a specified subsurface depth interval and is used as a basis for mapping the upper 50 feet of deposits. Resulting quantitative descriptions of the deposits are used to interpret the late Quaternary history of the area. Three hydrogeologic units--Coast Range alluvium, flood-basin deposits, and Sierran sand--can be recognized in the upper 50 feet of deposits in the central part of the western San Joaquin Valley. The upper 30 feet of Coast Range alluvium and the adjacent 5 to 35 feet of flood-basin deposits are predominantly fine grained. These fine-grained Coast Range deposits are underlain by coarse-grained channel deposits. The fine-grained flood basin deposits are underlain by coarse-grained Sierran sand. The extent and orientation of channel deposits below 20 feet in the Coast Range alluvium indicate that streams draining the Coast Range may have been tributary to the axial stream that deposited the Sierran sand and that streamflow may have been to the southeast. The fining-upward stratigraphic sequence in the upper 50 feet of deposits and the headward retreat of tributary stream channels from the valley trough with time support a recent hypothesis of climatic control of alluviation in the western San Joaquin Valley.

Coal-tar-based pavement sealcoat—Potential concerns for human health and aquatic life

USGS Publications Warehouse

Mahler, Barbara J.; Woodside, Michael D.; Van Metre, Peter C.

2016-04-20

Aquatic Life Concerns—Runoff from coal-tar-sealcoated pavement, even runoff collected more than 3 months after sealcoat application, is acutely toxic to fathead minnows and water fleas, two species commonly used to assess toxicity to aquatic life. Exposure to even highly diluted runoff from coal-tar-sealcoated pavement can cause DNA damage and impair DNA repair. These findings demonstrate that coal-tar-sealcoat runoff can remain a risk to aquatic life for months after application.

Measurements of wind, aeolian sand transport, and precipitation in the Colorado River corridor, Grand Canyon, Arizona; January 2005 to January 2006

USGS Publications Warehouse

Draut, Amy E.; Rubin, David M.

2006-01-01

This report presents measurements of aeolian sediment-transport rates, wind speed and direction, and precipitation records from six locations that contain aeolian deposits in the Colorado River corridor through Grand Canyon, Grand Canyon National Park, Arizona. Aeolian deposits, many of which contain and preserve archaeological material, are an important part of the Grand Canyon ecosystem. This report contains data collected between January 2005 and January 2006, and is the second in a series; the first contained data that were collected between November 2003 and December 2004 (Draut and Rubin, 2005; http://pubs.usgs.gov/of/2005/1309/). Analysis of data collected in 2005 shows great spatial and seasonal variation in wind and precipitation patterns. Total annual rainfall can vary by more than a factor of two over distances ~ 10 km. Western Grand Canyon received substantially more precipitation than the eastern canyon during the abnormally wet winter of 2005. Great spatial variability in precipitation indicates that future sedimentary and geomorphic studies would benefit substantially from continued or expanded data collection at multiple locations along the river corridor, because rainfall records collected by NPS at Phantom Ranch (near river-mile 88) cannot be assumed to apply to other areas of the canyon. Wind velocities and sand transport in 2005 were greatest during May and June, with maximum winds locally as high as ~25 m s-1, and transport rates locally >100 g cm-1 d-1. This represents a later peak in seasonal aeolian sand transport compared to the previous year, in which transport rates were greatest in April and May 2004. Dominant wind direction varies with location, but during the spring windy season the greatest transport potential was directed upstream in Marble Canyon (eastern Grand Canyon). At all locations, rates of sand transport during the spring windy season were 5–15 times higher than at other times of year. This information has been used to

Effects of sand fences on coastal dune vegetation distribution

NASA Astrophysics Data System (ADS)

Grafals-Soto, Rosana

2012-04-01

Sand fences are important human adjustments modifying the morphology of developed shores. The effects of sand fences on sediment transport and deposition in their initial stages have been well studied, but little is known about the effect of deteriorated sand fences that have become partially buried low scale barriers within the dune, potentially benefiting vegetation growth by protecting it from onshore stress. Data on vegetation, topography and fence characteristics were gathered at three dune sites in Ocean City, New Jersey on September 2007 and March 2008 to evaluate the effect of fences within the dune on vegetation distribution. Variables include: distance landward of dune toe, degree of sheltering from onshore stressors, net change in surface elevation (deposition or erosion), vegetation diversity and density, presence of remnant fence, and distance landward of fence. Results for the studied environment reveal that 1) vegetation diversity or density does not increase near remnant fences because most remnants are lower than average vegetation height and can not provide shelter; but 2) vegetation distribution is related to topographic variables, such as degree of sheltering, that are most likely the result of sand accretion caused by fence deployment. Fence deployment that prioritizes the creation of topographically diverse dunes within a restricted space may increase the diversity and density of the vegetation, and the resilience and value of developed dunes. Managers should consider the benefits of using sand fences on appropriately wide beaches to create a protective dune that is also diverse, functional and better able to adapt to change.

Optical dating of tsunami-laid sand from an Oregon coastal lake

USGS Publications Warehouse

Ollerhead, J.; Huntley, D.J.; Nelson, A.R.; Kelsey, H.M.

2001-01-01

Optical ages for five samples of tsunami-laid sand from an Oregon coastal lake were determined using an infrared optical-dating method on K-feldspar separates and, as a test of accuracy, compared to ages determined by AMS 14C dating of detrital plant fragments found in the same beds. Two optical ages were about 20% younger than calibrated 14C ages of about 3.1 and 4.3 ka. Correction of the optical ages using measured anomalous fading rates brings them into agreement with the 14C ages. The approach used holds significant promise for improving the accuracy of infrared optical-dating methods. Luminescence data for the other three samples result in optical age limits much greater than the 14C ages. These data provide a textbook demonstration of the correlation between scatter in the luminescence intensity of individual sample aliquots and their normalization values that is expected when the samples contain sand grains not adequately exposed to daylight just prior to or during deposition and burial. Thus, the data for these three samples suggest that the tsunamis eroded young and old sand deposits before dropping the sand in the lake. ?? 2001 Elsevier Science Ltd. All rights reserved.

Bitumen recovery from oil sands using deep eutectic solvent and its aqueous solutions

NASA Astrophysics Data System (ADS)

Pulati, Nuerxida

Oil sands compose a significant proportion of the world's known oil reserves. Oil sands are also known as tar sands and bituminous sands, are complex mixtures of sand, clays, water and bitumen, which is "heavy" and highly viscous oil. The extraction and separation of bitumen from oil sands requires significant amount of energy and large quantities of water and poses several environmental challenges. Bitumen can be successfully separated from oil sands using imidazolium based ionic liquids and nonpolar solvents, however, ionic liquids are expensive and toxic. In this thesis, the ionic liquid alternatives- deep eutectic solvent, were investigated. Oil sands separation can be successfully achieved by using deep eutectic solvents DES (choline chloride and urea) and nonpolar solvent naphtha in different types of oil sands, including Canadian ("water-wet"), Utah ("oil-wet") and low grade Kentucky oil sands. The separation quality depends on oil sands type, including bitumen and fine content, and separation condition, such as solvent ratio, temperature, mixing time and mechanical centrifuge. This separation claims to the DES ability to form ion /charge layering on mineral surface, which results in reduction of adhesion forces between bitumen and minerals and promote their separation. Addition of water to DES can reduce DES viscosity. DES water mixture as a media, oil sands separation can be achieved. However, concentration at about 50 % or higher might be required to obtain a clear separation. And the separation efficiency is oil sands sample dependent. The highest bitumen extraction yield happened at 75% DES-water solution for Utah oil sands samples, and at 50 60% DES-water solutions for Alberta oil sands samples. Force curves were measured using Atomic Force Microscopy new technique, PeakForce Tapping Quantitative Nanomechanical Mapping (PFTQNM). The results demonstrate that, by adding DES, the adhesion force between bitumen and silica and dissipation energy will

Phytotoxicity and Plant Productivity Analysis of Tar-Enriched Biochars

NASA Astrophysics Data System (ADS)

Keller, M. L.; Masiello, C. A.; Dugan, B.; Rudgers, J. A.; Capareda, S. C.

2008-12-01

Biochar is one of the three by-products obtained by the pyrolysis of organic material, the other two being syngas and bio-oil. The pyrolysis of biomass has generated a great amount of interest in recent years as all three by-products can be put toward beneficial uses. As part of a larger project designed to evaluate the hydrologic impact of biochar soil amendment, we generated a biochar through fast pyrolysis (less than 2 minutes) of sorghum stock at 600°C. In the initial biochar production run, the char bin was not purged with nitrogen. This inadvertent change in pyrolysis conditions produced a fast-pyrolysis biochar enriched with tars. We chose not to discard this batch, however, and instead used it to test the impact of tar-enriched biochars on plants. A suite of phytotoxicity tests were run to assess the effects of tar-rich biochar on plant germination and plant productivity. We designed the experiment to test for negative effects, using an organic carbon and nutrient-rich, greenhouse- optimized potting medium instead of soil. We used Black Seeded Simpson lettuce (Lactuca sativa) as the test organism. We found that even when tars are present within biochar, biochar amendment up to 10% by weight caused increased lettuce germination rates and increased biomass productivity. In this presentation, we will report the statistical significance of our germination and biomass data, as well as present preliminary data on how biochar amendment affects soil hydrologic properties.

Carbazole is a naturally occurring inhibitor of angiogenesis and inflammation isolated from antipsoriatic coal tar

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jack L. Arbiser; Baskaran Govindarajan; Traci E. Battle

2006-06-15

Coal tar is one of the oldest and an effective treatment for psoriasis. Coal tar has been directly applied to the skin, or used in combination with UV light as part of the Goeckerman treatment. The use of coal tar has caused long-term remissions in psoriasis, but has fallen out of favor because the treatment requires hospitalization and coal tar is poorly acceptable aesthetically to patients. Thus, determining the active antipsoriatic component of coal tar is of considerable therapeutic interest. We fractionated coal tar into its components, and tested them using the SVR angiogenesis inhibitor assay. Treatment of SVR endothelialmore » cells with coal tar fractions resulted in the isolation of a single fraction with antiangiogenic activity. The active antiangiogenic compound in coal tar is carbazole. In addition to antiangiogenic activity, carbazole inhibited the production of inflammatory IL-15 by human mononuclear cells. IL-15 is elevated in psoriasis and is thought to contribute to psoriatic inflammation. Carbazole treatment also reduced activity of inducible nitric oxide synthase (iNOS), which is proinflammatory and elevated in psoriasis. The effect of carbazole on upstream pathways in human psoriasis was determined, and carbazole was shown to inhibit signal transducer and activator of transcription (stat)3-mediated transcription, which has been shown to be relevant in human psoriasis. IL-15, iNOS, and stat3 activation require the activation of the small GTPase rac for optimal activity. Carbazole was found to inhibit rac activation as a mechanism for its inhibition of downstream inflammatory and angiogenic pathways. Given its antiangiogenic and anti-inflammatory activities, carbazole is likely a major component of the antipsoriatic activity of coal tar. Carbazole and derivatives may be useful in the therapy of human psoriasis.« less

Deposits from the 12 July Dome Collapse and Explosive Activity at Soufriere Hills Volcano, 12-15 July 2003

NASA Astrophysics Data System (ADS)

Edmonds, M.; Herd, R.; Strutt, M.; Mann, C.

2003-12-01

A large dome collapse took place on 12-13 July 2003 at Soufriere Hills Volcano. This event was the largest in magnitude during the 1995-2003 eruption and involved over 120 million m3 andesite dome and talus material. The collapse took place over 18 hours and culminated in an explosive phase that continued intermittently until 15 July 2003. Prior to the collapse, the total volume of the dome was 230 million m3 and was made up of remnants of lava erupted 1997-2001, talus material and fresh andesite dome lava erupted during the last two years. Talus made up around 50% of the total dome volume. This paper describes and interprets the pyroclastic flow and airfall deposits from this event, using other monitoring data and empirical evidence to reconstruct the dome collapse. The airfall and pyroclastic flow deposits were studied in detail over the weeks following the collapse. Airfall deposits were studied at 45 locations around the island and 75 samples were collected for analysis. The surge deposit stretched over 10 km2 on land and 35 pits were dug at intervals through it. The sections were described and sampled, yielding a further 60 samples for grain size analysis. Further sampling was carried out on the block and ash deposits in the Tar River Valley and on the Tar River Fan. Pumices from the post-collapse explosion sequence were collected and their densities measured and mass coverage estimated. Deposit maps for airfall, lithics and pumices were constructed for all of the individual events and a map to show the distribution of the main surge unit was generated. The collapse was monitored in real-time using the MVO seismic network and observations from the field. The sequence of events was as follows. From 09:00 to 18:00, low-energy pyroclastic flows took place, confined to the Tar River Valley, which reached the sea at the mouth of Tar River. These flows gradually increased in energy throughout the day but were not associated with energetic, large surges. By 18:00 the

Reduced tar, nicotine, and carbon monoxide exposure while smoking ultralow- but not low-yield cigarettes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Benowitz, N.L.; Jacob, P. III; Yu, L.

An unresolved public health issue is whether some modern cigarettes are less hazardous than other and whether patients who cannot stop smoking should be advised to switch to lower-yield cigarettes. The authors studied tar (estimated by urine mutagenicity), nicotine, and carbon monoxide exposure in habitual smokers switched from their usual brand to high- (15 mg of tar), low- (5 mg of tar), or ultralow-yield (1 mg of tar) cigarettes. There were no differences in exposure comparing high- or low-yield cigarettes, but tar and nicotine exposures were reduced by 49% and 56%, respectively, and carbon monoxide exposure by 36% while smokingmore » ultralow-yield cigarettes. Similarly, in 248 subjects smoking their self-selected brand, nicotine intake, estimated by blood concentrations of its metabolite continine, was 40% lower in those who smoked ultralow but no different in those smoking higher yields of cigarettes. The data indicate that ultralow-yield cigarettes do deliver substantial doses of tar, nicotine, and carbon monoxide, but that exposure are considerably less than for other cigarettes.« less

Pollutant sensitivity of the endangered Tar River Spinymussel as assessed by single chemical and effluent toxicity tests

USGS Publications Warehouse

Augspurger, Thomas P.; Wang, Ning; Kunz, James L.; Ingersoll, Christopher G.

2014-01-01

The federally endangered Tar River spinymussel (Elliptio steinstansana) is endemic to the Tar River and Neuse River systems in North Carolina. The extent to which water quality limits Tar River spinymussels’ recovery is important to establish, and one aspect of that is understanding the species’ pollutant sensitivity. The primary objectives of this study were to 1) develop captive propagation and culture methods for Tar River spinymussels; 2) determine the pollutant sensitivity of captively propagated Tar River spinymussels; 3) examine the utility of the non-endangered yellow lance (Elliptio lanceolata), yellow lampmussel (Lampsilis cariosa) and notched rainbow (Villosa constricta) as surrogates for the Tar River spinymussels’ chemical sensitivity; 4) develop a 7-d method for conducting effluent toxicity tests starting with newly transformed mussels; 5) assess the toxicity of municipal wastewater effluents discharged into the Tar River spinymussels’ current and historic habitat; and, 6) evaluate the protection afforded by existing effluent toxicity test requirements.

Non-cohesive silt turbidity current flow processes; insights from proximal sandy-silt and silty-sand turbidites, Fiordland, New Zealand

NASA Astrophysics Data System (ADS)

Strachan, Lorna J.; Bostock, Helen C.; Barnes, Philip M.; Neil, Helen L.; Gosling, Matthew

2016-08-01

Silt-rich turbidites are commonly interpreted as distal marine deposits. They are associated with interlaminated clay and silt deposition from the upper and rear portions of turbidity currents. Here, multibeam bathymetry and shallow sediment core data from the intra-slope Secretary Basin, Fiordland, New Zealand, located < 10 km from shore, are used to describe a suite of late Holocene proximal sandy-silt and silty-sand turbidites that contain negligible clay and a wide variety of vertical grading patterns. The steep, rugged catchment to the Secretary Basin is dominated by a complex tributary turbidite channel network that feeds the low gradient Secretary Basin floor intra-slope lobe. Sediment core T49 is located within the lobe and positioned between shallow channels that are prone to deposition from decelerating, silty-sand and sandy-silt turbidity currents. The wide variety of sedimentary structures and vertical grading patterns, dominated by inversely graded beds, implies a range of non-cohesive flow processes, with deposition from multiphase, mixed mode (turbulent and laminar) flows that have undergone a variety of up-dip flow transformations. Most flows were initially erosive followed by deposition of partitioned 2- or 3- phase mixed mode flows that include high-density transitional and laminar flows that can be fore- or after-runners to low-density turbulent flow sections. Turbulence is inferred to have been suppressed in high-density flows by increasing flow concentration of both sands and silts. The very fine and fine sand modal grain sizes of sandy-silt and silty-sand turbidites are significantly coarser than classical abyssal plain silt turbidites and are generally coarser than overbank silt turbidites. While the low percentage of clays within Secretary Basin sandy-silt and silty-sand turbidites represents a fundamental difference between these and other silt and mud turbidites, we suggest these beds represent a previously undescribed suite of proximal

Effects of human chromosome 12 on interactions between Tat and TAR of human immunodeficiency virus type 1.

PubMed Central

Alonso, A; Cujec, T P; Peterlin, B M

1994-01-01

Rates of transcriptions of the human immunodeficiency virus are greatly increased by the viral trans activator Tat. In vitro, Tat binds to the 5' bulge of the trans-activation response (TAR) RNA stem-loop, which is present in all viral transcripts. In human cells, the central loop in TAR and its cellular RNA-binding proteins are also critical for the function of Tat. Previously, we demonstrated that in rodent cells (CHO cells), but not in those which contain the human chromosome 12 (CHO12 cells), Tat-TAR interactions are compromised. In this study, we examined the roles of the bulge and loop in TAR in Tat trans activation in these cells. Whereas low levels of trans activation depended solely on interactions between Tat and the bulge in CHO cells, high levels of trans activation depended also on interactions between Tat and the loop in CHO12 cells. Since the TAR loop binding proteins in these two cell lines were identical and different from their human counterpart, the human chromosome 12 does not encode TAR loop binding proteins. In vivo binding competition studies with TAR decoys confirmed that the binding of Tat to TAR is more efficient in CHO12 cells. Thus, the protein(s) encoded on human chromosome 12 helps to tether Tat to TAR via its loop, which results in high levels of trans activation. Images PMID:8083988

Sand resources, regional geology, and coastal processes for shoreline restoration: case study of Barataria shoreline, Louisiana

USGS Publications Warehouse

Kindinger, Jack G.; Flocks, James G.; Kulp, Mark; Penland, Shea; Britsch, Louis D.

2002-01-01

The Louisiana barrier shoreline of Barataria Basin, which lies within the western Mississippi River delta, has undergone significant retreat during the past 100 years. The most practical restoration method to rebuild these shorelines is sand nourishment. Seismic and sonar interpretations verified with geologic samples (vibracores and borings) indicate that there are nine sand targets within the Barataria study area that meet or exceed the minimum criteria for potential resource sites. However, the near surface lithology in the basin is typically silts and clays. Locating suitable sand resources for shoreline restoration is challenging. The sand units are associated with geologic depositional systems such as ebb-tidal deltas, distributary mouth bars, and channel fill (undifferentiated fluvial or tidal inlet channels). The nine potential sand targets consist primarily of fine sand and can be delineated into three surficial and six buried features. The surficial features contain approximately 10% of the total sand resources identified. At least 90% of the sand resources need overburden sediment removed prior to use; almost 570 million yd3 (438.5 mil m3) of overburden will need to be removed if the entire resource is mined. In this study, we identified 396 to 532 mil yd3 (305.8 to 410.8 mil m3) of potential sand deposits for shoreline restoration. Previous studies using less dense survey methods greatly over-estimated sand resources available in this area. Many fluvial channels reported previously as sand-filled are mud-filled. Contrary to these previous studies, few fluvial subsystems in this region have abundant sand resources.

Influence of cigarette filter ventilation on smokers' mouth level exposure to tar and nicotine.

PubMed

Caraway, John W; Ashley, Madeleine; Bowman, Sheri A; Chen, Peter; Errington, Graham; Prasad, Krishna; Nelson, Paul R; Shepperd, Christopher J; Fearon, Ian M

2017-12-01

Cigarette filter ventilation allows air to be drawn into the filter, diluting the cigarette smoke. Although machine smoking reveals that toxicant yields are reduced, it does not predict human yields. The objective of this study was to investigate the relationship between cigarette filter ventilation and mouth level exposure (MLE) to tar and nicotine in cigarette smokers. We collated and reviewed data from 11 studies across 9 countries, in studies performed between 2005 and 2013 which contained data on MLE from 156 products with filter ventilation between 0% and 87%. MLE among 7534 participants to tar and nicotine was estimated using the part-filter analysis method from spent filter tips. For each of the countries, MLE to tar and nicotine tended to decrease as filter ventilation increased. Across countries, per-cigarette MLE to tar and nicotine decreased as filter ventilation increased from 0% to 87%. Daily MLE to tar and nicotine also decreased across the range of increasing filter ventilation. These data suggest that on average smokers of highly ventilated cigarettes are exposed to lower amounts of nicotine and tar per cigarette and per day than smokers of cigarettes with lower levels of ventilation. Copyright © 2017 British American Tobacco. Published by Elsevier Inc. All rights reserved.

Impact of genetic variants on haematopoiesis in patients with thrombocytopenia absent radii (TAR) syndrome.

PubMed

Manukjan, Georgi; Bösing, Hendrik; Schmugge, Markus; Strauß, Gabriele; Schulze, Harald

2017-11-01

Thrombocytopenia absent radii (TAR) syndrome is clearly defined by the combination of radial aplasia and reduced platelet counts. The genetics of TAR syndrome has recently been resolved and comprises a microdeletion on Chromosome 1 including the RBM8A gene and a single nucleotide polymorphism (SNP) either at the 5' untranslated region (5'UTR) or within the first intron of RBM8A. Although phenotypically readily diagnosed after birth, the genetic determination of particular SNPs in TAR syndrome harbours valuable information to evaluate disease severity and treatment decisions. Here, we present clinical data in a cohort of 38 patients and observed that platelet counts in individuals with 5'UTR SNP are significantly lower compared to patients bearing the SNP in intron 1. Moreover, elevated haemoglobin values could only be assessed in patients with 5'UTR SNP whereas white blood cell count is unaffected, indicating that frequently observed anaemia in TAR patients could also be SNP-dependent whereas leucocytosis does not correlate with genetic background. However, this report on a large cohort provides an overview of important haematological characteristics in TAR patients, facilitating evaluation of the various traits in this disease and indicating the importance of genetic validation for TAR syndrome. © 2017 John Wiley & Sons Ltd.

Technology for the production of Zero Q.I pitch from coal tar

NASA Astrophysics Data System (ADS)

Karthik, K.; Kumar, K. Rajesh; Rao, C. V. Nageswara; Kumar, B. Vinod; Murty, J. V. S.

2013-06-01

Zero Quinoline Insolubles (Q.I) pitch is a special type of pitch obtained from pre-treatment of coal tar, which is converted into pitch. This is used for impregnation of electrodes for improving the strength, electrical properties and also used as a pre-cursor for Mesophase pitch for producing Mesophase pitch based carbon fibers, carbon foam, and Meso carbon micro beads. This paper discusses the technology of Q.I separation from Coal Tar by using decantation of Coal Tar mixed with Heavy Creosote Oil (HC Oil) at different temperatures. By this method we were able to produce the Zero Q.I pitch with a Q.I value of 0.1%.

Depositional environments of some Pleistocene coastal terrace deposits, southwestern Oregon - case history of progradational beach and dune sequence.

USGS Publications Warehouse

Hunter, R.E.

1980-01-01

These deposits comprise a basal gravelly unit and 3 overlying sandy units, each with mud beds, a paleosol, or the modern soil in its uppermost part. The gravelly unit is interpreted as a progradational deposit. The main parts of the sandy units are made up of 1) a crossbedded sand facies, the dominant structure in which is medium-scale crossbedding (interpreted as the product of small eolian dunes), and 2) an irregularly bedded sand facies, which is locally pebbly and is dominated by scour-and-fill structures, interpreted as deposits of interdune ephemeral streams, ephemeral ponds, and wet to dry subaerial flats. The mud beds and paleosols represent times of temporary stabilization of the dune field.- from Author

Exosomes from HIV-1-infected Cells Stimulate Production of Pro-inflammatory Cytokines through Trans-activating Response (TAR) RNA*

PubMed Central

Sampey, Gavin C.; Saifuddin, Mohammed; Schwab, Angela; Barclay, Robert; Punya, Shreya; Chung, Myung-Chul; Hakami, Ramin M.; Asad Zadeh, Mohammad; Lepene, Benjamin; Klase, Zachary A.; El-Hage, Nazira; Young, Mary; Iordanskiy, Sergey; Kashanchi, Fatah

2016-01-01

HIV-1 infection results in a chronic illness because long-term highly active antiretroviral therapy can lower viral titers to an undetectable level. However, discontinuation of therapy rapidly increases virus burden. Moreover, patients under highly active antiretroviral therapy frequently develop various metabolic disorders, neurocognitive abnormalities, and cardiovascular diseases. We have previously shown that exosomes containing trans-activating response (TAR) element RNA enhance susceptibility of undifferentiated naive cells to HIV-1 infection. This study indicates that exosomes from HIV-1-infected primary cells are highly abundant with TAR RNA as detected by RT-real time PCR. Interestingly, up to a million copies of TAR RNA/μl were also detected in the serum from HIV-1-infected humanized mice suggesting that TAR RNA may be stable in vivo. Incubation of exosomes from HIV-1-infected cells with primary macrophages resulted in a dramatic increase of proinflammatory cytokines, IL-6 and TNF-β, indicating that exosomes containing TAR RNA could play a direct role in control of cytokine gene expression. The intact TAR molecule was able to bind to PKR and TLR3 effectively, whereas the 5′ and 3′ stems (TAR microRNAs) bound best to TLR7 and -8 and none to PKR. Binding of TAR to PKR did not result in its phosphorylation, and therefore, TAR may be a dominant negative decoy molecule in cells. The TLR binding through either TAR RNA or TAR microRNA potentially can activate the NF-κB pathway and regulate cytokine expression. Collectively, these results imply that exosomes containing TAR RNA could directly affect the proinflammatory cytokine gene expression and may explain a possible mechanism of inflammation observed in HIV-1-infected patients under cART. PMID:26553869

Paleobiology of the Sand Beneath the Valders Diamicton at Valders, Wisconsin

NASA Astrophysics Data System (ADS)

Maher, Louis J.; Miller, Norton G.; Baker, Richard G.; Curry, B. Brandon; Mickelson, David M.

1998-03-01

Previously undescribed pollen, plant macrofossils, molluscs, and ostracodes were recovered from a 2.5-m-thick glaciolacustrine unit of silty sand and clay at Valders, Wisconsin. The interstadial sediment was deposited about 12,200 14C yr B.P. after retreat of the Green Bay lobe that deposited diamicton of the Horicon Formation, and before advance of the Lake Michigan lobe that deposited the red-brown diamicton of the Valders Member of the Kewaunee Formation. Fluctuations of abundance of Candona subtriangulata, Cytherissa lacustris,and three other species define four ostracode biozones in the lower 1.7 m, suggesting an open lake environment that oscillated in depth and proximity to glacial ice. Pollen is dominated by Piceaand Artemisia,but the low percentages of many other types of long-distance origin suggest that the terrestrial vegetation was open and far from the forest border. The upper part of the sediment, a massive sand deposited in either a shallow pond or a sluggish stream, contains a local concentration of plant macrofossils. The interpretation of a cold open environment is supported by the plant macrofossils of more than 20 species, dominated by those of open mineral soils ( Arenaria rubella, Cerastium alpinumtype, Silene acaulis, Sibbaldia procumbens, Dryas integrifolia, Vaccinium uliginosumvar. alpinum, Armeria maritima,etc.) that in North America occur largely in the tundra and open tundra-forest ecotone of northern Canada. Ice-wedge casts occur in the sand.

Paleobiology of the Sand Beneath the Valders Diamicton at Valders, Wisconsin

USGS Publications Warehouse

Maher, L.J.; Miller, N.G.; Baker, R.G.; Curry, B. Brandon; Mickelson, D.M.

1998-01-01

Previously undescribed pollen, plant macrofossils, molluscs, and ostracodes were recovered from a 2.5-m-thick glaciolacustrine unit of silty sand and clay at Valders, Wisconsin. The interstadial sediment was deposited about 12,200 14C yr B.P. after retreat of the Green Bay lobe that deposited diamicton of the Horicon Formation, and before advance of the Lake Michigan lobe that deposited the red-brown diamicton of the Valders Member of the Kewaunee Formation. Fluctuations of abundance of Candona subtriangulata, Cytherissa lacustris, and three other species define four ostracode biozones in the lower 1.7 m, suggesting an open lake environment that oscillated in depth and proximity to glacial ice. Pollen is dominated by Picea and Artemisia, but the low percentages of many other types of longdistance origin suggest that the terrestrial vegetation was open and far from the forest border. The upper part of the sediment, a massive sand deposited in either a shallow pond or a sluggish stream, contains a local concentration of plant macrofossils. The interpretation of a cold open environment is supported by the plant macrofossils of more than 20 species, dominated by those of open mineral soils (Arenaria rubella, Cerastium alpinum type, Silene acaulis, Sibbaldia procumbens, Dryas integrifolia, Vaccinium uliginosum var. alpinum, Armeria maritima, etc.) that in North America occur largely in the tundra and open tundra-forest ecotone of northern Canada. Ice-wedge casts occur in the sand. ?? 1998 University of Washington.

Physicochemical Approaches for the Remediation of Former Manufactured Gas Plant Tars

NASA Astrophysics Data System (ADS)

Hauswirth, S.; Miller, C. T.

2014-12-01

Former manufactured gas plant (FMGP) tars are one of the most challenging non-aqueous phase liquid (NAPL) contaminants to remediate due to their complex chemical composition, high viscosities, and ability to alter wettability. In this work, we investigate several in situ remediation techniques for the removal of tar from porous media. Batch and column experiments were conducted to test the effectiveness of mobilization, solubilization, and chemical oxidation remediation approaches. Alkaline (NaOH), surfactant (Triton X-100), and polymer (xanthan gum) agents were used in various combinations to reduce tar-water interfacial tension, increase flushing solution viscosity, and increase the solubilities of tar components. Base-activated sodium persulfate was used alone and in combination with surfactant to chemically oxidized tar components. The effectiveness of each method was assessed in terms of both removal of PAHs from the system and reduction of dissolved-phase effluent polycyclic aromatic hydrocarbon (PAH) concentrations. In column studies, alkaline-polymer (AP) and alkaline-surfactant-polymer (ASP) solutions efficiently mobilized 81-93% and 95-96% of residual PAHs, respectively, within two pore volumes. The impact of AP flushing on dissolved-phase PAH concentrations was relatively low; however, the concentrations of several low molar mass PAHs were significantly reduced after ASP flushing. Surfactant-polymer (SP) solutions removed over 99% of residual PAHs through a combination of mobilization and solubilization, and reduced the post-remediation, dissolved-phase total PAH concentration by 98.4-99.1%. Degradation of residual PAHs by base-activated sodium persulfate was relatively low (30-50%), and had little impact on dissolved-phase PAH concentrations.

Thermal Cracking of Tars in a Continuously Fed Reactor with Steam

DTIC Science & Technology

2011-05-01

Fluidized Bed using biomass 8 Tars  Mixture of organic components present in gasification product gas with high molecular weight hydrocarbons [MW...Disable sulfur removal systems FoulingPlugging [Ref. 3: Biomass Gasification – Tar and Particles in Product Gases Sampling and Analysis”, European...P., and Nussbaumer T., “Gas Cleaning Requirements for Internal Combustion Engine Applications of Fixed Bed Biomass Gasification ”, Biomass and

Cold Preparation of Heroin in a Black Tar Market.

PubMed

Roth, Alexis M; Armenta, Richard F; Wagner, Karla D; Strathdee, Steffanie A; Goldshear, Jesse L; Cuevas-Mota, Jazmine; Garfein, Richard S

2017-07-29

Black tar heroin is typically prepared for injection with heat which decreases the risk of HIV transmission by inactivating the virus. We received reports that persons who inject drugs (PWID) in Tijuana, Baja California, Mexico, a black tar heroin market, were using only water to dissolve heroin. Because Tijuana abuts San Diego County, CA, United States, we undertook the present analyses to determine the prevalence of this practice among PWID in San Diego, California. PWID completed quarterly behavioral assessments and serological testing for blood-borne viruses. Bivariate and multivariable logistic regression models were constructed to assess for individual, social, and structural correlates of preparing heroin without heat within the preceding 6 months. Nearly half of black tar heroin users (149/305) reported they had prepared heroin without heat within 6 months. In multivariable analysis, cold preparation was independently associated with younger age (10 year decrease; AOR = 1.25; 95% CI 1.03, 1.53), more drug injecting acquaintances (per 5 acquaintance increase; AOR = 1.05; 95% CI 1.01, 1.09) and prefilled syringe use (injecting drugs from syringes that are already filled with drugs before purchase; AOR = 1.86; 95% CI 1.14, 3.02). Conclusions/Importance: To our knowledge, this is the first paper to report that PWID living in a black tar heroin market are preparing heroin without heat. Additional research is needed to determine whether this is an endemic practice or PWID are engaging in new forms of drug preparation in response to changes in the environment.

The Auxin Biosynthetic TRYPTOPHAN AMINOTRANSFERASE RELATED TaTAR2.1-3A Increases Grain Yield of Wheat.

PubMed

Shao, An; Ma, Wenying; Zhao, Xueqiang; Hu, Mengyun; He, Xue; Teng, Wan; Li, Hui; Tong, Yiping

2017-08-01

Controlling the major auxin biosynthetic pathway to manipulate auxin content could be a target for genetic engineering of crops with desired traits, but little progress had been made because low or high auxin contents often cause developmental inhibition. Here, we performed a genome-wide analysis of bread wheat ( Triticum aestivum ) to identify the Tryptophan Aminotransferase of Arabidopsis1/Tryptophan Aminotransferase-Related (TAA1/TAR) genes that function in the tryptophan-dependent pathway of auxin biosynthesis. Sequence mining together with gene cloning identified 15 TaTAR genes, among which 12 and three genes were phylogenetically close to Arabidopsis ( Arabidopsis thaliana ) AtTAR2 and AtTAR3, respectively. TaTAR2.1 had the most abundant transcripts in the TaTAR2 genes and was expressed mainly in roots and up-regulated by low nitrogen (N) availability. Knockdown of TaTAR2.1 caused vegetative and reproductive deficiencies and impaired lateral root (LR) growth under both high- and low-N conditions. Overexpressing TaTAR2.1-3A in wheat enhanced LR branching, plant height, spike number, grain yield, and aerial N accumulation under different N supply levels. In addition, overexpressing TaTAR2.1-3A in Arabidopsis elevated auxin accumulation in the primary root tip, LR tip, LR primordia, and cotyledon and hypocotyl and increased primary root length, visible LR number, and shoot fresh weight under high- and low-N conditions. Our results indicate that TaTAR2.1 is critical for wheat growth and also shows potential for genetic engineering to reach the aim of improving the grain yield of wheat. © 2017 American Society of Plant Biologists. All Rights Reserved.

Use of mineral oil Fleet enema for the removal of a large tar burn: a case report.

PubMed

Carta, Tricia; Gawaziuk, Justin; Liu, Song; Logsetty, Sarvesh

2015-03-01

Extensive hot tar burns are relatively uncommon. Management of these burns provides a significant clinical challenge especially with respect to tar removal involving a large total body surface area (TBSA), without causing further tissue injury. We report a case of an over 40-year old male construction worker who was removing a malfunctioning cap from broken valve. This resulted in tar spraying over the anterior surface of his body including legs, feet, chest, abdomen, arms, face and oral cavity (80% TBSA covered in tar resulting in a 50% TBSA burn injury). Initially, petrolatum-based, double antibiotic ointment was used to remove the tar, based on our previous experience with small tar burns. However, this was time-consuming and ineffective. The tar was easily removed with mineral oil without irritation. In order to meet the demand for quantity of mineral oil, the pharmacy suggested using mineral oil Fleet enema (C.B. Fleet Company, Inc., Lynchburg, Virginia, USA). The squeezable bottle and catheter tip facilitated administration of oil into the patient's construction boots and under clothing that was adhered to the patient's skin. Tar removal requires an effective, non-toxic and non-irritating agent. Mineral oil is such an agent. For patients that may present with a large surface area tar burn, using mineral oil Fleet enema is a viable option that facilitates application into difficult areas. Grant Support: The Firefighters' Burn Fund (Manitoba) supported this project. Copyright © 2014 Elsevier Ltd and ISBI. All rights reserved.

Experimental Study of Sand Production and Mud Erosion Phenomena for Sand Mud Alternate Layer

NASA Astrophysics Data System (ADS)

Oyama, H.; Sato, T.

2014-12-01

Methane hydrates are crystalline, ice-like compounds under specific thermodynamic conditions. The existence of methane hydrates is confirmed in the Nankai Trough, an offshore area of Japan. Japan's Methane Hydrate Research and Development Program (MH21) has been under way at this area. In the early 2013, the world's first intentional gas production attempt from marine gas hydrate deposits was tried and accomplished in the Daini Atumi Knoll area of the Eastern Nankai Trough. For gas production, depressurization method has been considered as a promising gas production technique from methane hydrate reservoirs. However, considering of continuous gas production over a long period, there is still something to clarify. The methane hydrate crystals are very small and existed in the intergranular pores of sandy layer of turbidite sediments. When the intergranular methane hydrates will be dissociated, it is considered that dissociated gas and water flow will cause sand production and mud erosion phenomena of turbidite sediments. The production of framework sands into a well is one of the problems plaguing the gas because of its adverse effects on well productivity and equipment. If the eroded mud is accumulated in the pore space of sand, skin is generated and permeability becomes lower. In addition, mud erosion has a negative effect for the well stability. This research presents an experimental study to understand sand production and mud erosion phenomena for sand mud alternate layer. The aims of this study are to understand these phenomena and clarify driving forces. In our experiments, we used an artificial sedimentary core and performed experiments under various conditions. As the results, the driving forces of these phenomena are not dissociation gas flow but water flow through pore.

Partitioning studies of coal-tar constituents in a two-phase contaminated ground-water system

USGS Publications Warehouse

Rostad, C.E.; Pereira, W.E.; Hult, M.F.

1985-01-01

Organic compounds derived from coal-tar wastes in a contaminated aquifer in St. Louis Park, Minnesota, were identified, and their partition coefficients between the tar phase and aqueous phase were determined and compared with the corresponding n-octanol/water partition coefficients. Coal tar contains numerous polycyclic aromatic compounds, many of which are suspected carcinogens or mutagens. Groundwater contamination by these toxic compounds may pose an environmental health hazard in nearby public water-supply wells. Fluid samples from this aquifer developed two phases upon settling: an upper aqueous phase, and a lower oily-tar phase. After separating the phases, polycyclic aromatic compounds in each phase were isolated using complexation with N-methyl-2-pyrrolidone and identified by fused-silica capillary gas chromatography/mass spectrometry. Thirty-one of the polycyclic aromatic compounds were chosen for further study from four different classes: 12 polycyclic aromatic hydrocarbons, 10 nitrogen heterocycles, 5 sulfur heterocycles, and 4 oxygen heterocycles. Within each compound class, the tar/water partition coefficients of these compounds were reasonably comparable with the respective n-octanol/water partition coefficient.

Episodic Eolian Sand Deposition in the Past 4000 Years in Cape COD National Seashore, Massachusetts, USA in Response to Possible Hurricane/storm and Anthropogenic Disturbances

NASA Astrophysics Data System (ADS)

Forman, Steven

2015-02-01

The eolian sand depositional record for a dune field within Cape Cod National Seashore, Massachusetts is posit as a sensitive indicator of environmental disturbances in the late Holocene from a combination of factors such as hurricane/storm and forest fire occurrence, and anthropogenic activity. Stratigraphic and sedimentologic observations, particularly the burial of spodosol-like soils, and associated 14C and OSL ages that are concordant indicate at least six eolian depositional events at ca. 3750, 2500, 1800, 960, 430 and <250 years ago. The two oldest events are documented at just one locality and thus, the pervasiveness of this eolian activity is unknown. However, the four younger events are identified in three or more sites and show evidence for dune migration and sand sheet accretion. The timing of eolian deposition, particularly the initiation age, corresponds to documented periods of increased storminess/hurricane activity in the North Atlantic Ocean at ca. 2.0 to 1.6, and 1.0 ka and also a wetter coastal climate, which suppressed the occurrence of forest fire. Thus, local droughts are not associated with periods of dune movement in this mesic environment. Latest eolian activity on outer Cape Cod commenced in the past 300 to 500 years and may reflect multiple factors including broad-scale landscape disturbance with European colonization, an increased incidence of forest fires and heightened storminess. Eolian systems of Cape Cod appear to be sensitive to landscape disturbance and prior to European settlement may reflect predominantly hurricane/storm disturbance, despite generally mesic conditions in past 4 ka.

Assessment of Mud-Capped Dredge Pit Evolution Offshore Louisiana: Implications to Sand Excavation and Coastal Restoration

NASA Astrophysics Data System (ADS)

Xu, K.; Miner, M. D.; Bentley, S. J.; Li, C.; Obelcz, J.; O'Connor, M. C.

2016-02-01

The shelf offshore Louisiana is characterized by a dominantly muddy seafloor with a paucity of restoration-quality sand proximal to shore. Discrete sand deposits associated with ancient rivers that incised the shelf during lower sea-level positions occur close to shore. These shelf channel sands have been targeted for coastal restoration projects resulting in significant cost savings over more distal deposits. Several recent projects targeted shelf paleo-fluvial deposits comprising relatively deep (10 m) channel sands underlying a muddy overburden. Because of contrasting characteristics of cohesive mud vs. non-cohesive sand and potential modern fluvial mud supply from the Mississippi and Atchafalaya Rivers, long term pit evolution is poorly understood relative to their more common sand-only counterparts. Alterations to seafloor topography from dredging shelf sediment resources can potentially affect oil and gas infrastructure or other resources of concern (i.e. historic shipwrecks) located proximal to dredge pits. Site-specific data required to make accurate predictions and empirical measurements to test and validate predictive models were only available for Peveto Channel offshore Holly Beach, Louisiana. Here we present new geophysical and geological data (bathymetry, sidescan, subbottom, and radionuclide of sediment cores) and physical oceanographic observations (hydrodynamics and sediment dynamics) collected at Raccoon Island (dredged in 2013) dredge pit in Louisiana. These field data collections along with pre-existing data provide a time-series to capture evolution at Raccoon Island post-excavation. Conceptual morphological models will be developed for dredge pit evolution and testing effectiveness of setback buffers protecting pipelines, habitats, and cultural resources. Our results will increase decision making ability regarding safety and protecting environmental and cultural resources, and better management of valuable sand resources.

The importance of sand in the formation of avulsion channels within experimental fans that develop from sediment mixtures of mud and sand

NASA Astrophysics Data System (ADS)

Iscen, N.; Strom, K.

2017-12-01

Autogenic channel migration and avulsion has long been recognized as important drivers of alluvial fan dynamics. In the literature, several field studies have documented that the presence and the amount of sand transport through a channel is important for channel incision in alluvial fans and deltas. In our experiments, we present the general autogenic avulsion cycle of experimental alluvial fans with mixtures of cohesive sediment and sand with a range of boundary conditions, and we detail the importance of mobile sand fraction in the development of channels that lead to avulsion. Experimental observations demonstrate that new channels form at topographically low regions within the floodplain providing that sand is transported to these topographic lows due to overbank flow or levee breaching. In addition to the sediment transported from upstream, erosion of a previous deposit and an ongoing backfilling nearby are observed as the possible sources of sand getting into the ghost channels. We explore whether the presence of sand is important for channel development because it increases abrasion of the channel or because it changes the roughness characteristics of the flow. We also examine the affect of sediment and water supply change on the newly described channelization process and link distinctive channel morphologies to different stages of described channel development and the avulsion process.

A photographic method for estimating wear of coal tar sealcoat from parking lots

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mateo Scoggins; Tom Ennis; Nathan Parker

2009-07-01

Coal-tar-based sealcoat has been recognized as an important source of PAHs to the environment through wear and transport via stormwater runoff. Sealcoat removal rates have not been measured or even estimated in the literature due to the complex array of physical and chemical process involved. A photographic study was conducted that incorporates all sources of wear using 10 coal tar-sealed parking lots in Austin, Texas, with sealcoat age ranging from 0 to 5 years. Randomly located photographs from each parking lot were analyzed digitally to quantify black sealed areas versus lighter colored unsealed areas at the pixel level. The resultsmore » indicate that coal tar sealcoat wears off of the driving areas of parking lots at a rate of approximately 4.7% per year, and from the parking areas of the lots at a rate of approximately 1.4% per year. The overall annual loss of sealcoat was calculated at 2.4%. This results in an annual delivery to the environment of 0.51 g of PAHs per m{sup 2} of coal tar-sealed parking lot. These values provide a more robust and much higher estimate of loading of PAHs from coal tar sealcoated parking lots when compared to other available measures. 20 refs., 6 figs.« less

Clear cutting (10-13th century) and deep stable economy (18-19th century) as responsible interventions for sand drifting and plaggic deposition in cultural landscapes on aeolian sands (SE-Netherlands).

NASA Astrophysics Data System (ADS)

van Mourik, Jan; Vera, Hein; Wallinga, Jakob

2013-04-01

The landscape in extensive areas in SE-Netherlands is underlain by coversand, deposited during the Late Glacial of the Weichselian. In the Preboreal, aeolian processes reduced soil formation. From the Preboreal to the Atlantic a deciduous climax forest developed. The geomorphology was a coversand landscape, composed of ridges (umbric podzols), coversand plains (gleyic podzols), coversand depressions (histic podzols) and small valleys (gleysols). The area was used by hunting people during the Late Paleolithic and Mesolithic. During the Bronze and Iron Ages the area was populated by people, living from forest grazing, shifting cultivation and trade. The natural deciduous forest gradually degraded into Calluna heath. The deforestation accelerated the soil acidification and affected the hydrology, which is reflected in drying out of ridges and wetting of depressions, promoting the development of histic podzols and even histosols. Aeolian erosion was during this period restricted to local, small scale sand drifting, related to natural hazards as forest fires and hurricanes and shifting cultivation. Sustainable crop productivity on chemically poor sandy substrates required application of organic fertilizers, composed of a mixture of organic litter and animal manure with a very low mineral compound, produced in shallow stables. At least since 1000 AD, heath management was regulated by a series of rules that aimed to protect the valuable heat lands against degradation. During the 11th, 12th and 13th centuries there was an increasing demand for wood and clear cutting transformed the majority of the forests in driftsand landscapes. The most important market was formed by the very wealthy Flemish cities. The exposed soil surface was subjected to wind erosion and sand drifting which endangered the Calluna heath, arable land and even farmhouses. As a consequence, umbric podzols, the natural climax soil under deciduous forests on coversand, degraded into larger scale driftsand

Morphology of transverse aeolian ridges (TARs) on Mars from a large sample: Further evidence of a megaripple origin?

NASA Astrophysics Data System (ADS)

Hugenholtz, Chris H.; Barchyn, Thomas E.; Boulding, Adam

2017-04-01

Using HiRISE digital terrain models (DTMs), we developed a large morphological dataset to examine the three-dimensional shape, size, and scaling of Martian transverse aeolian ridges (TARs). Considerable debate exists on the characteristic morphology of TARs and the origins of these enigmatic bedforms. Some researchers suggest polygenesis or multiple classes of similar bedforms. Reliably characterizing the morphology of TARs is an essential prerequisite to developing and evaluating process-based models of TAR genesis and unraveling aeolian processes on the surface of Mars. We present measurements of TAR morphology from a large, DTM-derived dataset (n = 2295). We focused on TARs with 'simple' morphologies in order enable more defensible discretization. Histograms and cumulative log-frequency plots of morphometric parameters (length, width, height, elongation ratio, and wavelength) indicate the sample represents a continuum of bedforms from a single population. A typical TAR from our dataset is 88.5 m long (longest planview axis), 17.3 m wide (shortest planview axis), 1.3 m tall, and has a wavelength of 25.8 m. Combined with these data, the bulk of evidence presented to date suggests that interpreting TARs as megaripples is the most viable working hypothesis.

Impacts of Cation Type and Clay on Transport of Surface-modified Nanoparticles through Saturated Sand Columns

NASA Astrophysics Data System (ADS)

Torkzaban, S.; Wan, J.; Tokunaga, T. K.

2010-12-01

Transport of three different nanoparticles (NPs) was studied in columns packed with different sands (unwashed Accusand, washed Accusand, and ultrapure quartz) at different ionic strengths (IS) and cation types. The NPs were functionalized (polyacrylic acid) quantum dots (QDs), carboxylic-modified latex, and bare silica. Scanning electron microscopy (SEM) and energy-dispersive X-ray (EDX) analysis showed there were regions on the unwashed Accusand grains covered with clay particles. The SEM images of washed Accusand showed that the sand surfaces contained significantly less clay coatings. The breakthrough curves (BTCs) of QDs and latex NPs from unwashed Accusand columns showed minute deposition at 50 and 100 mM Na+. However, significant NP deposition occurred in unwashed Accusand columns at 0.5, 1, and 2 mM Ca2+. The amount of deposition increased as the Ca2+ concentration was increased. These results suggest that, in contrast to monovalent Na+, divalent Ca2+ enhanced deposition of the NPs. The BTCs of QDs and latex NPs in washed Accusand exhibited a similar trend as those of unwashed Accusand, however, much less deposition occurred at any given IS. The BTCs from the ultrapure quartz sand column showed negligible QD deposition at 2 mM Ca2+. Following completion of column experiments, a few Accusand sand grains were analyzed with SEM and the images showed that most of QDs were deposited on the clay surfaces. In contrast with our results from surface-modified NPs, the column experiments using bare silica NPs at 5 mM Ca2+ in unwashed Accusand showed negligible deposition. The enhanced deposition of surface-modified NPs may be attributed to cation bridging in which Ca2+ cations serve as a bridge between the NP, which contain carboxyl group on its surface, and negatively charged clay surfaces at 7. Because Ca2+ is commonly a major cation in groundwater, our results suggest that transport of carboxylic ligand-modified NPs may be very limited in subsurface environments.

TarPmiR: a new approach for microRNA target site prediction.

PubMed

Ding, Jun; Li, Xiaoman; Hu, Haiyan

2016-09-15

The identification of microRNA (miRNA) target sites is fundamentally important for studying gene regulation. There are dozens of computational methods available for miRNA target site prediction. Despite their existence, we still cannot reliably identify miRNA target sites, partially due to our limited understanding of the characteristics of miRNA target sites. The recently published CLASH (crosslinking ligation and sequencing of hybrids) data provide an unprecedented opportunity to study the characteristics of miRNA target sites and improve miRNA target site prediction methods. Applying four different machine learning approaches to the CLASH data, we identified seven new features of miRNA target sites. Combining these new features with those commonly used by existing miRNA target prediction algorithms, we developed an approach called TarPmiR for miRNA target site prediction. Testing on two human and one mouse non-CLASH datasets, we showed that TarPmiR predicted more than 74.2% of true miRNA target sites in each dataset. Compared with three existing approaches, we demonstrated that TarPmiR is superior to these existing approaches in terms of better recall and better precision. The TarPmiR software is freely available at http://hulab.ucf.edu/research/projects/miRNA/TarPmiR/ CONTACTS: haihu@cs.ucf.edu or xiaoman@mail.ucf.edu Supplementary data are available at Bioinformatics online. © The Author 2016. Published by Oxford University Press.

Tar analysis from biomass gasification by means of online fluorescence spectroscopy

NASA Astrophysics Data System (ADS)

Baumhakl, Christoph; Karellas, Sotirios

2011-07-01

Optical methods in gas analysis are very valuable mainly due to their non-intrusive character. That gives the possibility to use them for in-situ or online measurements with only optical intervention in the measurement volume. In processes like the gasification of biomass, it is of high importance to monitor the gas quality in order to use the product gas in proper machines for energy production following the restrictions in the gas composition but also improving its quality, which leads to high efficient systems. One of the main problems in the biomass gasification process is the formation of tars. These higher hydrocarbons can lead to problems in the operation of the energy system. Up to date, the state of the art method used widely for the determination of tars is a standardized offline measurement system, the so-called "Tar Protocol". The aim of this work is to describe an innovative, online, optical method for determining the tar content of the product gas by means of fluorescence spectroscopy. This method uses optical sources and detectors that can be found in the market at low cost and therefore it is very attractive, especially for industrial applications where cost efficiency followed by medium to high precision are of high importance.

Identification of discontinuous sand pulses on the bed of the Colorado River in Grand Canyon

NASA Astrophysics Data System (ADS)

Mueller, E. R.; Grams, P. E.; Buscombe, D.; Topping, D. J.

2017-12-01

Decades of research on alluvial sandbars and sand transport on the Colorado River in Grand Canyon has contributed to in-depth understanding of the sand budget and lead to management actions designed to rebuild eroded sandbars. However, some basic, but difficult to address, questions about the processes and rates of sand movement through the system still limit our ability to predict geomorphic responses. The coarse fraction of the bed is heterogeneous and varies among boulders, cobble, gravel, and bedrock. Sand covers these substrates in patches of variable size and thickness, fills interstices to varying degrees, and forms mixed sand/coarse bed configurations such as linear stripes. Understanding the locations of sand accumulation, the quantities of sand contained in those locations, and the processes by which sand is exchanged among depositional locations is needed to predict the morphological response of sandbars to management actions, such as the controlled flood releases, and to predict whether sandbars are likely to increase or decrease in size over long (i.e. decadal) time periods. Here, we present evidence for the downstream translation of the sand component of tributary sediment inputs as discontinuous sand pulses. The silt and clay (mud) fraction of sediment introduced episodically by seasonal floods from tributary streams is transported entirely in suspension and moves through the 400 km series of canyons in a few days. The sand fraction of this sediment, which is transported on the bed and in suspension, moves downstream in sand pulses that we estimate range in length from a few km to tens of km. Owing to the complex geomorphic organization, the sand pulses are not detectable as coherent bed features; each individual sand pulse is comprised of many isolated storage locations, separated by rapids and riffles where sand cover is sparse. The presence of the sand pulses is inferred by the existence of alternating segments of sand accumulation and depletion

Prey-sensing and orientational behaviors of sand scorpions

NASA Astrophysics Data System (ADS)

Brownell, Philip

2000-03-01

Sand scorpions use exquisitely sensitive vibrational and chemosensory systems to locate prey and identify prospective mates active on the sand surface. Prey location is determined by input to a static array of 8 vibration-sensitive receptors, each responding as phase-locked accelerometers to compressional and surface waves conducted through sand. Angular orientation of the target is determined from passing surface (Rayleigh) waves, target distance possibly from the time delay between arrival of compressional and surface waves. For localization and identification of prospective mates, male scorpions use sexually dimorphic chemosensory appendages, the pectines, which are swept over a static stimulus field (chemical trail deposited on sand). These organs support a 2D array of closely-spaced (freq = 100/mm) sensilla containing more than 10^6 neurons, all projecting with great topographic precision to the central nervous system. Movement of this sensory array over a static stimulus field creates timing within the sensory signal. The potential importance of timing as a means of increasing sensitivity and selectivity of sensory response in two distinctly different modes is discussed.

Submarine sand dunes and sedimentary environments in Oceanographer Canyon.

USGS Publications Warehouse

Valentine, P.C.; Cooper, R.A.; Uzmann, J.R.

1984-01-01

Observations from research submersibles in the northern part of Oceanographer Canyon reveal the presence of an extensive field of large sand dunes on the canyon floor. The dunes are medium to coarse sand, are oriented across the axis, and the largest of them are as high as 3 m and have wavelengths up to 15 m. Their asymmetry, grain size, and height suggest that they are formed by axial currents flowing up- and downcanyon and that the largest dunes require flows of at least 70 cm/sec. Shelf sand, low in silt and clay content, is transported by currents down and along the canyon walls onto the canyon floor. As the sand enters the canyon, it is mixed with immobile gravel deposits on the canyon rim; lower on the walls, the sand is mixed with silt and clay burrowed by organisms from the semiconsolidated sandy silt that underlies the canyon walls and floor. Upon reaching the canyon floor, the sand is sculpted into bed forms by currents, and the fines are winnowed out and transported out of the canyon. At present, the shelf and canyon walls are being eroded by bottom currents and burrowing organisms, whereas the canyon floor is covered by mobile sand that moves both up and down the axis in this part of the canyon.

Skin cancer in patients with psoriasis treated with coal tar. A 25-year follow-up study

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pittelkow, M.R.; Perry, H.O.; Muller, S.A.

1981-08-01

For many years, crude coal tar has been used for the treatment of psoriasis. The possible carcinogenic effect of crude coal tar and ultraviolet (UV) radiation (Goeckerman regimen), considered individually or in combination, has been of some concern to physicians. A 25-year follow-up study was completed on 280 patients with psoriasis who were hospitalized and treated with crude coal tar and UV radiation at the Mayo Clinic, Rochester, Minn, during the years 1950 through 1954. The results of this study suggest that the incidence of skin cancer is not appreciably increased above the expected incidence for the general population whenmore » patients are treated with coal tar ointments. It seems that the Goeckerman regimen (topical crude coal tar combined with UV radiation) can be used with minimal risk for skin cancer in the treatment of psoriasis.« less

Volatilization of polycyclic aromatic hydrocarbons from coal-tar-sealed pavement

USGS Publications Warehouse

Van Metre, Peter C.; Majewski, Michael S.; Mahler, Barbara J.; Foreman, William T.; Braun, Christopher L.; Wilson, Jennifer T.; Burbank, Teresa L.

2012-01-01

Coal-tar-based pavement sealants, a major source of PAHs to urban water bodies, are a potential source of volatile PAHs to the atmosphere. An initial assessment of volatilization of PAHs from coal-tar-sealed pavement is presented here in which we measured summertime gas-phase PAH concentrations 0.03 m and 1.28 m above the pavement surface of seven sealed (six with coal-tar-based sealant and one with asphalt-based sealant) and three unsealed (two asphalt and one concrete) parking lots in central Texas. PAHs also were measured in parking lot dust. The geometric mean concentration of the sum of eight frequently detected PAHs (ΣPAH8) in the 0.03-m samples above sealed lots (1320 ng m-3) during the hottest part of the day was 20 times greater than that above unsealed lots (66.5 ng m-3). The geometric mean concentration in the 1.28-m samples above sealed lots (138 ng m-3) was five times greater than above unsealed lots (26.0 ng m-3). Estimated PAH flux from the sealed lots was 60 times greater than that from unsealed lots (geometric means of 88 and 1.4 μg m-2 h-1, respectively). Although the data set presented here is small, the much higher estimated fluxes from sealed pavement than from unsealed pavement indicate that coal-tar-based sealants are emitting PAHs to urban air at high rates compared to other paved surfaces.

Laboratory studies of dune sand for the use of construction industry in Sri Lanka

NASA Astrophysics Data System (ADS)

de Silva Jayawardena, Upali; Wijesuriya, Roshan; Abayaweera, Gayan; Viduranga, Tharaka

2015-04-01

With the increase of the annual sand demand for the construction industry the excessive excavation of river sand is becoming a serious environmental problem in Sri Lanka. Therefore, it is necessary to explore the possibility for an alternative to stop or at least to minimize river sand mining activities. Dune sand is one of the available alternative materials to be considered instead of river sand in the country. Large quantities of sand dunes occur mainly along the NW and SE coastal belt which belong to very low rainfall Dry Zone coasts. The height of dune deposits, vary from 1m to about 30 meters above sea level. The objective of this paper is to indicate some studies and facts on the dune sand deposits of Sri Lanka. Laboratory studies were carried out for visual observations and physical properties at the initial stage and then a number of tests were carried out according to ASTM standards to obtain the compressive strength of concrete cylinders and mortar cubes mixing dune sand and river sand in different percentages keeping a constant water cement ratio. Next the water cement ratio was changed for constant dune sand and river sand proportion. Microscopic analysis shows that the dune sand consist of 95 % of quartz and 5 % of garnet, feldspar, illmenite and other heavy minerals with clay, fine dust, fine shell fragments and organic matters. Grains are sub-rounded to angular and tabular shapes. The grain sizes vary from fine to medium size of sand with silt. The degree of sorting and particle size observed with dune sands are more suited with the requirement of fine aggregates in the construction industry. The test result indicates that dune sand could be effectively used in construction work without sieving and it is ideal for wall plastering due to its'-uniformity. It could also be effectively used in concrete and in mortars mixing with river sand. The best mixing ratio is 75% dune sand and 25% river sand as the fine aggregate of concrete. For mortar the mixing

Iron(II) supramolecular helicates interfere with the HIV-1 Tat–TAR RNA interaction critical for viral replication

PubMed Central

Malina, Jaroslav; Hannon, Michael J.; Brabec, Viktor

2016-01-01

The interaction between the HIV-1 transactivator protein Tat and TAR (transactivation responsive region) RNA, plays a critical role in HIV-1 transcription. Iron(II) supramolecular helicates were evaluated for their in vitro activity to inhibit Tat–TAR RNA interaction using UV melting studies, electrophoretic mobility shift assay, and RNase A footprinting. The results demonstrate that iron(II) supramolecular helicates inhibit Tat-TAR interaction at nanomolar concentrations by binding to TAR RNA. These studies provide a new insight into the biological potential of metallosupramolecular helicates. PMID:27405089

Iron(II) supramolecular helicates interfere with the HIV-1 Tat-TAR RNA interaction critical for viral replication.

PubMed

Malina, Jaroslav; Hannon, Michael J; Brabec, Viktor

2016-07-12

The interaction between the HIV-1 transactivator protein Tat and TAR (transactivation responsive region) RNA, plays a critical role in HIV-1 transcription. Iron(II) supramolecular helicates were evaluated for their in vitro activity to inhibit Tat-TAR RNA interaction using UV melting studies, electrophoretic mobility shift assay, and RNase A footprinting. The results demonstrate that iron(II) supramolecular helicates inhibit Tat-TAR interaction at nanomolar concentrations by binding to TAR RNA. These studies provide a new insight into the biological potential of metallosupramolecular helicates.

Holocene beach buildup and coastal aeolian sand incursions off the Nile littoral cell

NASA Astrophysics Data System (ADS)

Roskin, Joel; Sivan, Dorit; Shtienberg, Gilad; Porat, Naomi; Bookman, Revital

2017-04-01

Israel's coastal plain is abundant with sand originating from the Nile littoral cell. The inland windblown loose sand has formed 3-6 km wide lobe-like sand and dune fields currently comprised of foredunes, linear and northeasterly facing transverse and parabolic dunes that are currently stabilized by vegetation. This study reviews the architecture and history of the these dune fields aiming to: (a) Date the timings of beach accretion, and sand and dune incursions. (b) Discriminate between natural and human-induced forcing factors of sand mobilization and stabilization in time and space. (c) Present a model of the dunescape development. (d) Assess scenarios of sand transport in the future charcaterized by intense human impact and climate change. Luminescence ages, radiocarbon dates and relative ages from previously published geological and archaeological reports, historical texts, together with new optically stimulated luminescence (OSL) ages and stratigraphic and sedimentological data are analyzed. The deposition, mobilizations and preservation of the sand bodies, initially induced by the decline in sea level rise at 6-4 ka, were later controlled by historic land-use intensity and modern land-use/negligence practices. At 6 ka, beach sand buildup rapidly started. Where aeolianite ridges bordered the coast, pulses of sand with biogenic carbonate grains unconformably draped the ridges and rapidly consolidated into a distinct sandy calcarenite unit. Further east, sand sheets and low dunes partly pedogenized following their incursion, but did not cement. The water retention capacities of the sand sheets enabled the establishment of a sand-stabilizing vegetation cover that probably became an attractive environment for fuel and grazing. The growing Hellenistic-Roman-Byzantine ( 2.4-1.3 ka) populations probably led to increased consumption and massive destruction of sand stabilizing vegetation, enabling sand erodibility and mobilization during winter storms. The sand

MAHLI at the Rocknest sand shadow: Science and science-enabling activities

NASA Astrophysics Data System (ADS)

Minitti, M. E.; Kah, L. C.; Yingst, R. A.; Edgett, K. S.; Anderson, R. C.; Beegle, L. W.; Carsten, J. L.; Deen, R. G.; Goetz, W.; Hardgrove, C.; Harker, D. E.; Herkenhoff, K. E.; Hurowitz, J. A.; Jandura, L.; Kennedy, M. R.; Kocurek, G.; Krezoski, G. M.; Kuhn, S. R.; Limonadi, D.; Lipkaman, L.; Madsen, M. B.; Olson, T. S.; Robinson, M. L.; Rowland, S. K.; Rubin, D. M.; Seybold, C.; Schieber, J.; Schmidt, M.; Sumner, D. Y.; Tompkins, V. V.; Van Beek, J. K.; Van Beek, T.

2013-11-01

Martian solar days 57-100, the Mars Science Laboratory Curiosity rover acquired and processed a solid (sediment) sample and analyzed its mineralogy and geochemistry with the Chemistry and Mineralogy and Sample Analysis at Mars instruments. An aeolian deposit—herein referred to as the Rocknest sand shadow—was inferred to represent a global average soil composition and selected for study to facilitate integration of analytical results with observations from earlier missions. During first-time activities, the Mars Hand Lens Imager (MAHLI) was used to support both science and engineering activities related to sample assessment, collection, and delivery. Here we report on MAHLI activities that directly supported sample analysis and provide MAHLI observations regarding the grain-scale characteristics of the Rocknest sand shadow. MAHLI imaging confirms that the Rocknest sand shadow is one of a family of bimodal aeolian accumulations on Mars—similar to the coarse-grained ripples interrogated by the Mars Exploration Rovers Spirit and Opportunity—in which a surface veneer of coarse-grained sediment stabilizes predominantly fine-grained sediment of the deposit interior. The similarity in grain size distribution of these geographically disparate deposits support the widespread occurrence of bimodal aeolian transport on Mars. We suggest that preservation of bimodal aeolian deposits may be characteristic of regions of active deflation, where winnowing of the fine-sediment fraction results in a relatively low sediment load and a preferential increase in the coarse-grained fraction of the sediment load. The compositional similarity of Martian aeolian deposits supports the potential for global redistribution of fine-grained components, combined with potential local contributions.

Process for removing heavy metal compounds from heavy crude oil

DOEpatents

Cha, Chang Y.; Boysen, John E.; Branthaver, Jan F.

1991-01-01

A process is provided for removing heavy metal compounds from heavy crude oil by mixing the heavy crude oil with tar sand; preheating the mixture to a temperature of about 650.degree. F.; heating said mixture to up to 800.degree. F.; and separating tar sand from the light oils formed during said heating. The heavy metals removed from the heavy oils can be recovered from the spent sand for other uses.

Structure, age and origin of the bay-mouth shoal deposits, Chesapeake Bay, Virginia

USGS Publications Warehouse

Colman, Steven M.; Berquist, C.R.; Hobbs, C. H.

1988-01-01

The mouth of Chesapeake Bay contains a distinctive shoal complex and related deposits that result from the complex interaction of three different processes: (1) progradation of a barrier spit at the southern end of the Delmarva Peninsula, (2) strong, reversing tidal currents that transport and rework sediment brought to the bay mouth from the north, and (3) landward (bayward) net non-tidal circulation and sediment transport. Together, these processes play a major role in changing the configuration of the estuary and filling it with sediment. The deposits at the mouth of the bay hold keys both to the evolution of the bay during the Holocene transgression and to the history of previous generations of the bay. The deposit associated with the shoals at the mouth of the bay, the bay-mouth sand, is a distinct stratigraphic unit composed mostly of uniform, gray, fine sand. The position and internal structure of the unit shows that it is related to near-present sea level, and thus is less than a few thousand years old. The processes affecting the upper surface of the deposit and the patterns of erosion and deposition at this surface are complex, but the geometry and structure of the deposit indicate that it is a coherent unit that is prograding bayward and tending to fill the estuary. The source of the bay-mouth sand is primarily outside the bay in the nearshore zone of the Delmarva Peninsula and on the inner continental shelf. The internal structure of the deposit, its surface morphology, its heavy-mineral composition, bottom-current studies, comparative bathymetry, and sediment budgets all suggest that sand is brought to the bay mouth by southerly longshore drift along the Delmarva Peninsula and then swept into the bay. In addition to building the southward- and bayward-prograding bay-mouth sand, these processes result in sand deposition tens of kilometers into the bay. ?? 1988.

Seismic stratigraphy and depositional history of late Quaternary deposits at the eastern Yellow Sea shelf

NASA Astrophysics Data System (ADS)

Yoo, Dong-Geun; Lee, Gwang-Soo; Kim, Gil-Young; Chang, Se-Won; Kim, Kyoung-Jin

2017-04-01

The late Quaternary stratigraphy and sedimentation at the eastern Yellow Sea shelf was studied using a dense network of high-resolution, single-channel seismic reflection profiles and sediment data. The shelf sequence in this area consists of six seismic units formed since the LGM. During the LGM, the study area was completely exposed, resulting in subaerial erosion associated with paleo-channel incision by the Huanghe and Korean Rivers. As the shelf was flooded, the incised channels were backfilled fluvial or coastal sediments, forming incised channel-fill deposits (SU1). The paleo-river may have supplied abundant terrigenous sediments to the study area around the paleo-river mouth and adjacent area. These sediments were trapped within the paleo-estuary and formed SU2, regarded as an estuarine deposit. Two types of serial sand ridges (SU3 and SU5) which correspond to transgressive deposits developed. SU3 on the southern part, west of Jeju Island (80 110 m deep) is regarded as a moribund-type mainly formed during the early to middle stage of transgression. These are thought to have ceased growing and remobilizing. In contrast, SU5 (occurring 30 50 m deep off the Korean Peninsula) is generally regarded as active sand ridges deposited during the late stage of transgression and is partly modified by modern tidal currents. As the transgression continued, the near-surface sediments were reworked and redistributed by shelf erosion, resulting in a thin veneer of transgressive sands (SU4). The uppermost unit (SU6) formed the Heuksan Mud Belt (HMB), which is one of the most prominent mud deposits in the Yellow Sea. The lower part of the HMD corresponds to shelf-mud deposited during the late stage of transgression, whereas the upper part consists of a recent shelf-delta developed after the highstand sea level at about 7 ka BP.

Crystallization and preliminary X-ray diffraction analysis of the periplasmic domain of the Escherichia coli aspartate receptor Tar and its complex with aspartate

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mise, Takeshi; Matsunami, Hideyuki; Samatey, Fadel A.

The periplasmic domain of the E. coli aspartate receptor Tar was cloned, expressed, purified and crystallized with and without bound ligand. The crystals obtained diffracted to resolutions of 1.58 and 1.95 Å, respectively. The cell-surface receptor Tar mediates bacterial chemotaxis toward an attractant, aspartate (Asp), and away from a repellent, Ni{sup 2+}. To understand the molecular mechanisms underlying the induction of Tar activity by its ligands, the Escherichia coli Tar periplasmic domain with and without bound aspartate (Asp-Tar and apo-Tar, respectively) were each crystallized in two different forms. Using ammonium sulfate as a precipitant, crystals of apo-Tar1 and Asp-Tar1 weremore » grown and diffracted to resolutions of 2.10 and 2.40 Å, respectively. Alternatively, using sodium chloride as a precipitant, crystals of apo-Tar2 and Asp-Tar2 were grown and diffracted to resolutions of 1.95 and 1.58 Å, respectively. Crystals of apo-Tar1 and Asp-Tar1 adopted space group P4{sub 1}2{sub 1}2, while those of apo-Tar2 and Asp-Tar2 adopted space groups P2{sub 1}2{sub 1}2{sub 1} and C2, respectively.« less

A tsunami deposit from Vancouver Island, Canada ― Geological evidence for the penultimate great Cascadia earthquake?

NASA Astrophysics Data System (ADS)

Tanigawa, K.; Sawai, Y.; Bobrowsky, P. T.; Huntley, D.; Goff, J. R.; Shinozaki, T.

2017-12-01

We examined tsunami deposits within salt marshes at Tofino, Ucluelet and Port Alberni along the west coast of Vancouver Island aligned with the Cascadia Subduction Zone. Previous studies in 1990s reported tsunami deposits associated with the 1964 Alaska, the 1700 Cascadia and older earthquakes from these sites (Clague and Bobrowsky, 1994a; b). However, the ages of older tsunami deposits were not well constrained. We excavated pits and collected salt marsh sediments in 2015 and 2016. Sand layers interbedded within peat and mud deposits occur at widely separated sites on Vancouver Island. Two visible sand layers were observed in Tofino, four in Ucluelet and three in Port Alberni; which is consistent with previous studies. We used a combination of 210Pb, 137Cs and 14C dating to constrain the depositional ages of sand layers. Plant microfossils and insects obtained directly above and below each sand layer were used for radiocarbon dating. Radiocarbon ages indicate that the sand layer prior to the 1700 tsunami sediments was deposited between 550-300 calendar years before present. This depositional age is correlative to the T2 event of the Cascadia Subduction Zone turbidite history (Goldfinger et al., 2012). References: Clague and Bobrowsky (1994a) Quaternary Research, 41, 176-184. Clague and Bobrowsky (1994b) GSA Bulletin 106, 1293-1303. Goldfinger et al. (2012) USGS Professional Paper 1661-F, 170 p.

Risk Assessment for Children Exposed to Beach Sands Impacted by Oil Spill Chemicals

PubMed Central

Black, Jennifer C.; Welday, Jennifer N.; Buckley, Brian; Ferguson, Alesia; Gurian, Patrick L.; Mena, Kristina D.; Yang, Ill; McCandlish, Elizabeth; Solo-Gabriele, Helena M.

2016-01-01

Due to changes in the drilling industry, oil spills are impacting large expanses of coastlines, thereby increasing the potential for people to come in contact with oil spill chemicals. The objective of this manuscript was to evaluate the health risk to children who potentially contact beach sands impacted by oil spill chemicals from the Deepwater Horizon disaster. To identify chemicals of concern, the U.S. Environmental Protection Agency’s (EPA’s) monitoring data collected during and immediately after the spill were evaluated. This dataset was supplemented with measurements from beach sands and tar balls collected five years after the spill. Of interest is that metals in the sediments were observed at similar levels between the two sampling periods; some differences were observed for metals levels in tar balls. Although PAHs were not observed five years later, there is evidence of weathered-oil oxidative by-products. Comparing chemical concentration data to baseline soil risk levels, three metals (As, Ba, and V) and four PAHs (benzo[a]pyrene, benz[a]anthracene, benzo[b]fluoranthene, and dibenz[a,h]anthracene) were found to exceed guideline levels prompting a risk assessment. For acute or sub-chronic exposures, hazard quotients, computed by estimating average expected contact behavior, showed no adverse potential health effects. For cancer, computations using 95% upper confidence limits for contaminant concentrations showed extremely low increased risk in the 10−6 range for oral and dermal exposure from arsenic in sediments and from dermal exposure from benzo[a]pyrene and benz[a]anthracene in weathered oil. Overall, results suggest that health risks are extremely low, given the limitations of available data. Limitations of this study are associated with the lack of toxicological data for dispersants and oil-spill degradation products. We also recommend studies to collect quantitative information about children’s beach play habits, which are necessary to more

Gravel Mobility in a High Sand Content Riverbed

NASA Astrophysics Data System (ADS)

Haschenburger, J. K.

2017-12-01

In sand-gravel channels, sand may modify gravel transport by changing conditions of entrainment and promoting longer displacements or gravel may inhibit sand transport if concentrated into distinct deposits, which restrict sand supply with consequences for migrating bedform size or form. This study reports on gravel mobility in the lower San Antonio River, Texas, where gravel content in the bed material ranges from about 1% to more than 20%. Sediment transport observations were collected at three U.S. Geological Survey gauging stations by deploying a Helley-Smith sampler with a 0.2 mm mesh bag from which transport rates and mobile grain sizes were determined. The flow rates sampled translate into an annual exceedance expectation from 0.2% to 98%. Gravel transport rates are generally two orders of magnitude smaller than the rates of sand transport. However, the finest gravels are transported at rates on the same order of magnitude as the coarsest sands. At all sites, the 2 and 2.8 mm fractions are transported at the lowest flow rate sampled, suggesting mobility for at least 38% to as much as 98% of the year. Fractions as large as 8 mm are mobilized at flow rates that are expected between 25% and 53% of the year. The largest fractions captured in the sampling (16 to 32 mm) require flows closer to bankfull conditions that occur no more than 0.8% of the year. Results document that some gravel sizes can be frequently transported in low gradient riverbeds with high sand content.

Diverse Deposits in Melas Chasma

NASA Image and Video Library

2015-07-29

This scene captured by NASA Mars Reconnaissance Orbiter includes chaotic deposits with a wide range of colors. The deposits are distinctive with both unique colors and small-scale textures such as fracture patterns. These are probably sedimentary rocks, transported and deposited in water or air. The original layers may have been jumbled in a landslide. Dark or reddish sand dunes cover some of the bedrock. http://photojournal.jpl.nasa.gov/catalog/PIA19860

Pesticide and transformation product detections and age-dating relations from till and sand deposits

USGS Publications Warehouse

Warner, K.L.; Morrow, W.S.

2007-01-01

Pesticide and transformation product concentrations and frequencies in ground water from areas of similar crop and pesticide applications may vary substantially with differing lithologies. Pesticide analysis data for atrazine, metolachlor, alachlor, acetochlor, and cyanazine and their pesticide transformation products were collected at 69 monitoring wells in Illinois and northern Indiana to document occurrence of pesticides and their transformation products in two agricultural areas of differing lithologies, till, and sand. The till is primarily tile drained and has preferential fractured flow, whereas the sand primarily has surface water drainage and primary porosity flow. Transformation products represent most of the agricultural pesticides in ground water regardless of aquifer material - till or sand. Transformation products were detected more frequently than parent pesticides in both the till and sand, with metolachlor ethane sulfonic acid being most frequently detected. Estimated ground-water recharge dates for the sand were based on chlorofluorocarbon analyses. These age-dating data indicate that ground water recharged prior to 1990 is more likely to have a detection of a pesticide or pesticide transformation product. Detections were twice as frequent in ground water recharged prior to 1990 (82%) than in ground water recharged on or after 1990 (33%). The highest concentrations of atrazine, alachlor, metolachlor, and their transformation products, also were detected in samples from ground water recharged prior to 1990. These age/pesticide detection relations are opposite of what would normally be expected, and may be the result of preferential flow and/or ground-water mixing between aquifers and aquitards as evident by the detection of acetochlor transformation products in samples with estimated ground-water ages predating initial pesticide application. ?? 2007 American Water Resources Association.

Data report for the geologic and scenic quality evaluation of selected sand and gravel sites on the Wind River Indian Reservation, Wyoming

USGS Publications Warehouse

Langer, William H.; Van Gosen, Bradley S.; Arbogast, Belinda; Lindsey, David A.

2011-01-01

In April 2005, the U.S. Geological Survey (USGS) conducted field studies on the Wind River Indian Reservation, Wyoming, to inventory and evaluate sand and gravel deposits underlying river terraces on tribal lands along the Wind River. This report contains the results for 12 sites of sand and gravel deposits evaluated for their potential use as aggregate in Portland cement concrete, asphalt, and base course. The report provides the results of: * The USGS geologic studies and engineering tests. * A conclusion and recommendation for the best use of sand and gravel materials. * Calculations of available sand and gravel materials. * A scenic quality landscape inventory and evaluation.

Potential contributions of asphalt and coal tar to black carbon quantification in urban dust, soils, and sediments

USGS Publications Warehouse

Yang, Y.; Mahler, B.J.; Van Metre, P.C.; Ligouis, B.; Werth, C.J.

2010-01-01

Measurements of black carbon (BC) using either chemical or thermal oxidation methods are generally thought to indicate the amount of char and/or soot present in a sample. In urban environments, however, asphalt and coal-tar particles worn from pavement are ubiquitous and, because of their pyrogenic origin, could contribute to measurements of BC. Here we explored the effect of the presence of asphalt and coal-tar particles on the quantification of BC in a range of urban environmental sample types, and evaluated biases in the different methods used for quantifying BC. Samples evaluated were pavement dust, residential and commercial area soils, lake sediments from a small urban watershed, and reference materials of asphalt and coal tar. Total BC was quantified using chemical treatment through acid dichromate (Cr2O7) oxidation and chemo-thermal oxidation at 375??C (CTO-375). BC species, including soot and char/charcoal, asphalt, and coal tar, were quantified with organic petrographic analysis. Comparison of results by the two oxidation methods and organic petrography indicates that both coal tar and asphalt contribute to BC quantified by Cr2O7 oxidation, and that coal tar contributes to BC quantified by CTO-375. These results are supported by treatment of asphalt and coal-tar reference samples with Cr2O7 oxidation and CTO-375. The reference asphalt is resistant to Cr2O7 oxidation but not to CTO-375, and the reference coal tar is resistant to both Cr2O7 oxidation and CTO-375. These results indicate that coal tar and/or asphalt can contribute to BC measurements in samples from urban areas using Cr2O7 oxidation or CTO-375, and caution is advised when interpreting BC measurements made with these methods. ?? 2010 Elsevier Ltd.

A comparison of physicochemical methods for the remediation of porous medium systems contaminated with tar

NASA Astrophysics Data System (ADS)

Hauswirth, Scott C.; Miller, Cass T.

2014-10-01

The remediation of former manufactured gas plant (FMGP) sites contaminated with tar DNAPLs (dense non-aqueous phase liquids) presents a significant challenge. The tars are viscous mixtures of thousands of individual compounds, including known and suspected carcinogens. This work investigates the use of combinations of mobilization, solubilization, and chemical oxidation approaches to remove and degrade tars and tar components in porous medium systems. Column experiments were conducted using several flushing solutions, including an alkaline-polymer (AP) solution containing NaOH and xanthan gum (XG), a surfactant-polymer (SP) solution containing Triton X-100 surfactant (TX100) and XG, an alkaline-surfactant-polymer (ASP) solution containing NaOH, TX100, and XG, and base-activated sodium persulfate both with and without added TX100. The effectiveness of the flushing solutions was assessed based on both removal of polycyclic aromatic hydrocarbon (PAH) mass and on the reduction of dissolved-phase PAH concentrations. SP flushes of 6.6 to 20.9 PV removed over 99% of residual PAH mass and reduced dissolved-phase concentrations by up to two orders of magnitude. ASP flushing efficiently removed 95-96% of residual PAH mass within about 2 PV, and significantly reduced dissolved-phase concentrations of several low molar mass compounds, including naphthalene, acenaphthene, fluorene, and phenanthrene. AP flushing removed a large portion of the residual tar (77%), but was considerably less effective than SP and ASP in terms of the effect on dissolved PAH concentrations. Persulfate was shown to oxidize tar components, primarily those with low molar mass, however, the overall degradation was relatively low (30-50% in columns with low initial tar saturations), and the impact on dissolved-phase concentrations was minimal.

Estimated sand and gravel resources of the South Merrimack, Hillsborough County, New Hampshire, 7.5-minute quadrangle

USGS Publications Warehouse

Sutphin, D.M.; Drew, L.J.; Fowler, B.K.

2006-01-01

A computer methodology is presented that allows natural aggregate producers, local governmental, and nongovernmental planners to define specific locations that may have sand and gravel deposits meeting user-specified minimum size, thickness, and geographic and geologic criteria, in areas where the surficial geology has been mapped. As an example, the surficial geologic map of the South Merrimack quadrangle was digitized and several digital geographic information system databases were downloaded from the internet and used to estimate the sand and gravel resources in the quadrangle. More than 41 percent of the South Merrimack quadrangle has been mapped as having sand and (or) gravel deposited by glacial meltwaters. These glaciofluvial areas are estimated to contain a total of 10 million m3 of material mapped as gravel, 60 million m3 of material mapped as mixed sand and gravel, and another 50 million m3 of material mapped as sand with minor silt. The mean thickness of these areas is about 1.95 meters. Twenty tracts were selected, each having individual areas of more than about 14 acres4 (5.67 hectares) of stratified glacial-meltwater sand and gravel deposits, at least 10-feet (3.0 m) of material above the watertable, and not sterilized by the proximity of buildings, roads, streams and other bodies of water, or railroads. The 20 tracts are estimated to contain between about 4 and 10 million short tons (st) of gravel and 20 and 30 million st of sand. The five most gravel-rich tracts contain about 71 to 82 percent of the gravel resources in all 20 tracts and about 54-56 percent of the sand. Using this methodology, and the above criteria, a group of four tracts, divided by narrow areas sterilized by a small stream and secondary roads, may have the highest potential in the quadrangle for sand and gravel resources. ?? Springer Science+Business Media, LLC 2006.

Volatilization of polycyclic aromatic hydrocarbons from coal-tar-sealed pavement.

PubMed

Van Metre, Peter C; Majewski, Michael S; Mahler, Barbara J; Foreman, William T; Braun, Christopher L; Wilson, Jennifer T; Burbank, Teresa L

2012-06-01

Coal-tar-based pavement sealants, a major source of PAHs to urban water bodies, are a potential source of volatile PAHs to the atmosphere. An initial assessment of volatilization of PAHs from coal-tar-sealed pavement is presented here in which we measured summertime gas-phase PAH concentrations 0.03 m and 1.28 m above the pavement surface of seven sealed (six with coal-tar-based sealant and one with asphalt-based sealant) and three unsealed (two asphalt and one concrete) parking lots in central Texas. PAHs also were measured in parking lot dust. The geometric mean concentration of the sum of eight frequently detected PAHs (ΣPAH(8)) in the 0.03-m samples above sealed lots (1320 ng m(-3)) during the hottest part of the day was 20 times greater than that above unsealed lots (66.5 ng m(-3)). The geometric mean concentration in the 1.28-m samples above sealed lots (138 ng m(-3)) was five times greater than above unsealed lots (26.0 ng m(-3)). Estimated PAH flux from the sealed lots was 60 times greater than that from unsealed lots (geometric means of 88 and 1.4 μg m(-2) h(-1), respectively). Although the data set presented here is small, the much higher estimated fluxes from sealed pavement than from unsealed pavement indicate that coal-tar-based sealants are emitting PAHs to urban air at high rates compared to other paved surfaces. Published by Elsevier Ltd.

Development of secondary chamber for tar cracking-improvement of wood pyrolysis performance in pre-vacuum chamber

NASA Astrophysics Data System (ADS)

Siahaan, S.; Homma, H.; Homma, H.

2018-02-01

Energy crisis and global warming, in other words, climate change are critical topics discussed in various parts of the world. Global warming primarily result from too much emission of carbon dioxide (CO2) in the atmosphere. To mitigate global warming, or climate change and improve electrification in rural areas, wood pyrolysis technology is developed in a laboratory scale, of which gases are directly applicable to the gas engine generator. Our laboratory has developed a prototype of wood pyrolysis plant with a pre-vacuum chamber. However, tar yield was around 40 wt% of feedstock. This research aims to reduce tar yield by secondary tar cracking. For the secondary tar cracking, a secondary pre-vacuum chamber is installed after primary pre-vacuum chamber. Gases generated in the primary pre-vacuum chamber are lead into the secondary chamber that is heated up to 1000 K. This paper reports performance of the secondary chamber for secondary tar cracking in homogeneous mode and heterogeneous mode with char.

Nugget-Navaho-Aztec sandstone: interaction of eolian sand sea with Andean-type volcanic arc

DOE Office of Scientific and Technical Information (OSTI.GOV)

Marzolf, J.E.

1986-05-01

The Nugget-Navaho-Aztec sand sea was deposited east of an Andean-type volcanic arc. During the early stage of eolian deposition, fluvially transported sand was concentrated in the marine littoral zone and returned inland by onshore winds from the northwest. With progressive development of the arc, the sea withdrew. Wind direction changed from northwest to northeast. Previously deposited eolian sand was transported southwestward into the volcanic arc. Proximity of the arc can be detected with great difficulty by examining eolian and underlying red-bed facies. In southern Nevada, the volcanic arc is undetectable in eolian facies, but thin sandstone beds containing volcanic clastsmore » or weathered feldspar in the finer grained red-bed facies indicate arc volcanism; volcanic clasts are distinct in a basal conglomerate. Westward into California, the sub-Aztec Sandstone contains volcanic pebbles. The upper part of the Aztec Sandstone contains a 1 to 2-m thick volcaniclastic siltstone. Farther west, the Aztec Sandstone is interbedded with volcanic flows, ash flows, and flow breccias. These rocks might easily be mistaken for red beds in well cores or cuttings. Sand in sets of large-scale cross-beds remain virtually identical in composition and texture to sand in eolian facies of the Colorado Plateau. Where sets of eolian cross-beds lie on volcanics, the quartzose sandstone contains pebble to cobble-size volcanic clasts. Locally, cross-bed sets of yellowish-white, quartzose sandstone alternate with purplish-gray cross-bed sets containing numerous pebble to cobble-size volcanic clasts. The ability to recognize volcanic indicators within Nugget-Navaho-Aztec eolian facies is important in delineating the western margin of the back-arc eolian basin.« less

Hydraulic experiment on formation mechanism of tsunami deposit and verification of sediment transport model for tsunamis

NASA Astrophysics Data System (ADS)

Yamamoto, A.; Takahashi, T.; Harada, K.; Sakuraba, M.; Nojima, K.

2017-12-01

An underestimation of the 2011 Tohoku tsunami caused serious damage in coastal area. Reconsideration for tsunami estimation needs knowledge of paleo tsunamis. The historical records of giant tsunamis are limited, because they had occurred infrequently. Tsunami deposits may include many of tsunami records and are expected to analyze paleo tsunamis. However, present research on tsunami deposits are not able to estimate the tsunami source and its magnitude. Furthermore, numerical models of tsunami and its sediment transport are also important. Takahashi et al. (1999) proposed a model of movable bed condition due to tsunamis, although it has some issues. Improvement of the model needs basic data on sediment transport and deposition. This study investigated the formation mechanism of tsunami deposit by hydraulic experiment using a two-dimensional water channel with slope. In a fixed bed condition experiment, velocity, water level and suspended load concentration were measured at many points. In a movable bed condition, effects of sand grains and bore wave on the deposit were examined. Yamamoto et al. (2016) showed deposition range varied with sand grain sizes. In addition, it is revealed that the range fluctuated by number of waves and wave period. The measurements of velocity and water level showed that flow was clearly different near shoreline and in run-up area. Large velocity by return flow was affected the amount of sand deposit near shoreline. When a cutoff wall was installed on the slope, the amount of sand deposit repeatedly increased and decreased. Especially, sand deposit increased where velocity decreased. Takahashi et al. (1999) adapted the proposed model into Kesennuma bay when the 1960 Chilean tsunami arrived, although the amount of sand transportation was underestimated. The cause of the underestimation is inferred that the velocity of this model was underestimated. A relationship between velocity and sediment transport has to be studied in detail, but

Method for in situ heating of hydrocarbonaceous formations

DOEpatents

Little, William E.; McLendon, Thomas R.

1987-01-01

A method for extracting valuable constituents from underground hydrocarbonaceous deposits such as heavy crude tar sands and oil shale is disclosed. Initially, a stratum containing a rich deposit is hydraulically fractured to form a horizontally extending fracture plane. A conducting liquid and proppant is then injected into the fracture plane to form a conducting plane. Electrical excitations are then introduced into the stratum adjacent the conducting plate to retort the rich stratum along the conducting plane. The valuable constituents from the stratum adjacent the conducting plate are then recovered. Subsequently, the remainder of the deposit is also combustion retorted to further recover valuable constituents from the deposit. Various R.F. heating systems are also disclosed for use in the present invention.

Flow and sand transport over an immobile gravel bed.

USDA-ARS?s Scientific Manuscript database

Many dams in the USA and elsewhere have exceeded their design life and are being considered for remediation or removal, which will result in the reintroduction of fine sediments, often into coarse grained armored substrates, downstream of dams. The deposition of sand in the interstices of the grave...

Natural and human controls of the Holocene evolution of the beach, aeolian sand and dunes of Caesarea (Israel)

NASA Astrophysics Data System (ADS)

Roskin, J.; Sivan, D.; Shtienberg, G.; Roskin, E.; Porat, N.; Bookman, R.

2015-12-01

The study focuses on the Holocene appearance, chronology and drivers of beach sand deposition and inland aeolian sand transport around the Roman-Byzantine ruins of Caesarea, Israel. Beach sand, sand sheets, nebkha, linear and transverse dunes as well as parabolic and transverse interdunes along two transects were sampled in the current study down to their substrate. Sixteen new optically stimulated luminescence ages cluster at ∼5.9-3.3 ka, ∼1.2-1.1 ka (800-900 AD) and ∼190-120 years ago (1825-1895 AD) indicating times of middle and late Holocene sand sheet depositions and historical dune stabilization. The first age cluster indicates that beach sand accumulated when rates of global sea level rise declined around 6-5 ka. Until ∼4 ka sand sheets encroached up to 2.5 km inland. Historical and archaeological evidence points to sand mobilization since the first century AD. Sand sheets dating to 1.2-1.1 ka, coevally found throughout the dunefield represent sand stabilization due to vegetation reestablishment attributed to gradual and fluctuating decline in human activity from the middle Early Islamic period until the 10th century. Historical and chronological evidence of the existence of transverse and coppice dunes from the 19th century suggest that dunes only formed in the last few centuries. The study illustrates the initial role of natural processes, in this case decline in global sea level rise and the primary and later role of fluctuating human activity upon coastal sand mobility. The study distinguishes between sand sheets and dunes and portrays them as sensors of environmental changes.

Optical, Physical and Chemical Properties of Tar Balls Observed During the Yosemite Aerosol Characterization Study

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hand, Jenny L.; Malm, W. C.; Laskin, Alexander

2005-11-09

The Yosemite Aerosol Characterization Study of summer 2002 (YACS) occurred during an active fire season in the western U. S., and provided an opportunity to investigate many unresolved issues related to the radiative effects of biomass burning aerosols. Single particle analysis was performed on field collected aerosol samples using an array of electron microscopy techniques. Amorphous carbon spheres, or “tar balls”, were present in samples collected during episodes of high particle light scattering coefficients that occurred during the peak of a smoke/haze event. The highest concentrations of light-absorbing carbon from a dual-wavelength aethalometer (λ = 370 and 880 nm) occurredmore » during periods when the particles were predominantly tar balls, indicating they do absorb light in the UV and near-IR range of the solar spectrum. Closure experiments of mass concentrations and light scattering coefficients during periods dominated by tar balls did not require any distinct assumptions of organic carbon molecular weight correction factors, density, or refractive index compared to periods dominated by other types of organic carbon aerosols. Measurements of the hygroscopic behavior of tar balls using an environmental SEM indicate that tar balls do not exhibit deliquescence, but do uptake some water at high (~83 %) relative humidity. The ability of tar balls to efficiently scatter and absorb light, and to absorb water has important implications for their role in regional haze and climate fence.« less

Dissociation of Hexavalent Chromium from Sanded Paint Particles into a Simulated Lung Fluid

DTIC Science & Technology

2006-06-01

was simulated with a porcine based mucin . Sanded particles were collected based on particle size into the impactor’s six petri dishes, which...was used to imitate particle deposition onto a layer of lung fluid. The lung fluid was simulated with a porcine based mucin . Sanded particles were...documented as those directly related to corrosion control such as maintenance, repair, treatment , washing, painting, depainting, and sealing. These

A homemade sand-volcano in a gassy alluvial plain (Medolla, Italy): when shallow drilling triggers violent degassing

NASA Astrophysics Data System (ADS)

Capaccioni, Bruno; Coltorti, Massimo; Todesco, Micol; Cremoni, Stefano; Di Giuseppe, Dario; Faccini, Barbara; Tessari, Umberto

2017-04-01

Sand volcanoes are remarkable geological features which form when shallow, water-saturated sand deposits are set in motion and reach the surface. This commonly occurs during earthquakes, as a result of liquefaction of waterlogged bodies, but some of these sand emissions are unrelated to seismic events. We present the case of a sand eruption triggered by a Cone Penetration Test (CPT) near Medolla (Italy), on the 10th of October 2014. A large amount of natural gas (CO2 and CH4)was erupted together with a mixture of water and sand, creating a sand volcano. The event was recorded and its evolution and final result were analyzed from several points of view. Our multidisciplinary approach involved morphological and sedimentological studies on the sand-volcano, chemical and isotopic analysis of discharged gases, repeated measurements of gas flux on the drill hole and of diffuse degassing in the surrounding area and numerical modelling of the aquifer feeding the discharge. Our results suggest that a geyser discharging a mixture of gas and water, capable of building a sand volcano, requires the presence of a shallow pressurized reservoir (1.2 MPa) where water coexists with a small amount of exsolved gas (a volume fraction of 0.05). The violent degassing occurred in Medolla confirms the role that a free gas phase may have in favoring the mobilization of liquid water and loose deposits, even in the absence of a seismic event.

Comparative evaluation of topical calcipotriol versus coal tar and salicylic acid ointment in chronic plaque psoriasis.

PubMed

Singh, Preeti; Gupta, Surabhi; Abidi, Afroz; Krishna, Arvind

2013-08-01

Calcipotriol is a newer topical treatment option available for plaque psoriasis and coal tar being one of the oldest treatment and still in use. To evaluate and compare the differences in terms of efficacy, safety and relapse with Calcipotriol 0.005% (50 mcg/gm) and 6% coal tar and 3% salicylic ointment in patients with Plaque psoriasis. SETTING and Study conducted on 60 patients of plaque psoriasis, who attended the skin OPD in our hospital. The patients with mild to moderate plaque psoriasis were selected. 60 patients were enrolled for the study after obtaining informed consent. Subjects were asked to apply Calcipotriol 0.005% (50 mcg/gm) (Heximar Win care) twice a day on the right side plaques and on left side plaques, Petroleum jelly (Vaseline) in the morning and 6% coal tar and 3% salicylic ointment (Protar® Percos) at nighttime. PASI score was used to assess the reponse to therapy at 2nd, 4th, 6th and 8th week. After treatment subjects were observed for 6 weeks for any relapse. It was done by paired t-test and independent sample t-test. The results showed that statistically significant difference was seen in the mean percentage reduction of PASI score between both the groups, at all the assessment visits, 2, 4, 6, and 8 weeks, the mean percentage reduction at 2 weeks for calcipotriol being 21±12.06 and for coal tar being 13.44±11.19 (P=0.000), at 4 weeks for calcipotriol was 40±16.71 and for coal tar 25±99 (P=0.000), at 6 weeks for calcipotriol was 53.99+-22.43 and for coal tar 41±21.23 (P=0.002), at 8 weeks for calcipotriol was 62.73±24.04 and for coal tar was 51.53±23.27 (P=0.11). Relapse was seen in 5/60 (8.3%) of patients on calcipotriol treated side and 9/60 (15%) of patients with coal tar treated side. Thus it can be concluded that calcipotriol cream is more efficacious when compared with coal tar and does have a quick response. It is well tolerated and acceptable cosmetically.

Disturbance of the inclined inserting-type sand fence to wind-sand flow fields and its sand control characteristics

NASA Astrophysics Data System (ADS)

Cheng, Jian-jun; Lei, Jia-qiang; Li, Sheng-yu; Wang, Hai-feng

2016-06-01

The inclined inserting-type sand fence is a novel sand retaining wall adopted along the Lanxin High-Speed Railway II in Xinjiang for controlling and blocking sand movement. To verify the effectiveness of the new fence structure for sand prevention, a wind tunnel test was used for flow field test simulation of the sand fence. The results indicate that the inclined inserting-type sand fence was able to deflect the flow of the sand and was able to easily form an upward slant acceleration zone on the leeward side of the sand fence. As shown by the percentage change in sand collection rates on the windward side and the leeward side of the sand fence, the sand flux per unit area at 4 m height in the slant upward direction increased on the leeward side of the inclined inserting-type sand fence. By comparing the flow fields, this site is an acceleration zone, which also reaffirms the correspondence of wind-sand flow fields with the spatial distribution characteristic of the wind-carried sand motion. The field sand collection data indicates that under the effects of the inclined inserting-type sand fence, the sandy air currents passing in front and behind the sand fence not only changed in quality, but the grain composition and particle size also significantly changed, suggesting that the inclined inserting-type sand fence has a sorting and filtering effect on the sandy air currents that passed through. The fence retained coarse particulates on the windward side and fine particulates within the shade of the wind on the leeward side.

Selected constituents in the smokes of U. S. commercial cigaretts: tar, nicotine, carbon monoxide and carbon dioxide

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jenkins, R.A.; Quincy, R.B.; Guerin, M.R.

One hundred twenty-one brands of United States commercial cigarettes were analyzed for their deliveries of tar, nicotine, carbon monoxide, and carbon dioxide under standard analytical smoking conditions. The sample included both filter and nonfilter cigarettes. Comparisons of carbon monoxide deliveries over the range of observed tar deliveries indicated a very high correlation between CO and tar for filter cigarettes, but nonfilter cigarettes tended to produce much less CO than would have been predicted from their tar deliveries. Comparison of ORNL nicotine values for specific brands with those determined by the Federal Trade Commission yield no statistically significant differences between laboratories.more » 4 figures, 6 tables.« less

Ligand-induced changes in 2-aminopurine fluorescence as a probe for small molecule binding to HIV-1 TAR RNA

PubMed Central

BRADRICK, THOMAS D.; MARINO, JOHN P.

2004-01-01

Replication of human immunodeficiency virus type 1 (HIV-1) is regulated in part through an interaction between the virally encoded trans-activator protein Tat and the trans-activator responsive region (TAR) of the viral RNA genome. Because TAR is highly conserved and its interaction with Tat is required for efficient viral replication, it has received much attention as an antiviral drug target. Here, we report a 2-aminopurine (2-AP) fluorescence-based assay for evaluating potential TAR inhibitors. Through selective incorporation of 2-AP within the bulge (C23 or U24) of a truncated form of the TAR sequence (Δ TAR-ap23 and Δ TAR-ap24), binding of argininamide, a 24-residue arginine-rich peptide derived from Tat, and Neomycin has been characterized using steady-state fluorescence. Binding of argininamide to the 2-AP ΔTAR constructs results in a four- to 11-fold increase in fluorescence intensity, thus providing a sensitive reporter of that interaction (KD ~ 1 mM). Similarly, binding of the Tat peptide results in an initial 14-fold increase in fluorescence (KD ~ 25 nM), but is then followed by a slight decrease that is attributed to an additional, lower-affinity association(s). Using the ΔTAR-ap23 and TAR-ap24 constructs, two classes of Neomycin binding sites are detected; the first molecule of antibiotic binds as a noncompetitive inhibitor of Tat/argininamide (KD ~ 200 nM), whereas the second, more weakly bound molecule(s) becomes associated in a presumably nonspecific manner (KD ~ 4 μM). Taken together, the results demonstrate that the 2-AP fluorescence-detected binding assays provide accurate and general methods for quantitatively assessing TAR interactions. PMID:15273324

Vanadium Geochemistry of Oil Sands Fluid Petroleum Coke.

PubMed

Nesbitt, Jake A; Lindsay, Matthew B J

2017-03-07

Vanadium has previously been linked to elevated toxicity of leachates derived from oil sands petroleum coke. However, geochemical controls on V mobility within coke deposits remain poorly constrained. Detailed examinations of porewater and solid-phase V geochemistry were therefore performed on oil sands fluid petroleum coke deposits in Alberta, Canada. Sample collection focused on both active and reclaimed deposits, which contained more than 3 × 10 7 m 3 of fluid petroleum coke. Dissolved V concentrations were highest (up to 3.0 mg L -1 ) immediately below the water table but decreased rapidly with increasing depth. This trend corresponded to a transition from mildly acidic (pH 6-7) and oxic conditions to mildly alkaline (pH 7-8.5) and anoxic conditions. Scanning electron microscopy (SEM), electron microprobe analysis (EMPA), and micro-X-ray fluorescence (μXRF) mapping revealed coke particles exhibited an internal structure characterized by successive concentric layers. The outer margins of these layers were characterized by elevated V, Fe, Si, and Al concentrations, indicating the presence of inorganic phases. Micro-X-ray absorption near-edge structure (μXANES) spectroscopy revealed that V speciation was dominated by V(IV) porphyrins except at outer margins of layers, where octahedrally coordinated V(III) was a major component. Minor to trace V(V) was also detected within fluid petroleum coke particles.

Pyrolysis of aseptic packages (tetrapak) in a laboratory screw type reactor and secondary thermal/catalytic tar decomposition.

PubMed

Haydary, J; Susa, D; Dudáš, J

2013-05-01

Pyrolysis of aseptic packages (tetrapak cartons) in a laboratory apparatus using a flow screw type reactor and a secondary catalytic reactor for tar cracking was studied. The pyrolysis experiments were realized at temperatures ranging from 650 °C to 850 °C aimed at maximizing of the amount of the gas product and reducing its tar content. Distribution of tetrapak into the product yields at different conditions was obtained. The presence of H2, CO, CH4, CO2 and light hydrocarbons, HCx, in the gas product was observed. The Aluminum foil was easily separated from the solid product. The rest part of char was characterized by proximate and elemental analysis and calorimetric measurements. The total organic carbon in the tar product was estimated by elemental analysis of tars. Two types of catalysts (dolomite and red clay marked AFRC) were used for catalytic thermal tar decomposition. Three series of experiments (without catalyst in a secondary cracking reactor, with dolomite and with AFRC) at temperatures of 650, 700, 750, 800 and 850 °C were carried out. Both types of catalysts have significantly affected the content of tars and other components in pyrolytic gases. The effect of catalyst on the tetrapack distribution into the product yield on the composition of gas and on the total organic carbon in the tar product is presented in this work. Copyright © 2013 Elsevier Ltd. All rights reserved.

Identification of amino acids that promote specific and rigid TAR RNA-tat protein complex formation.

PubMed

Edwards, Thomas E; Robinson, Bruce H; Sigurdsson, Snorri Th

2005-03-01

The Tat protein and the transactivation responsive (TAR) RNA form an essential complex in the HIV lifecycle, and mutations in the basic region of the Tat protein alter this RNA-protein molecular recognition. Here, EPR spectroscopy was used to identify amino acids, flanking an essential arginine of the Tat protein, which contribute to specific and rigid TAR-Tat complex formation by monitoring changes in the mobility of nitroxide spin-labeled TAR RNA nucleotides upon binding. Arginine to lysine N-terminal mutations did not affect TAR RNA interfacial dynamics. In contrast, C-terminal point mutations, R56 in particular, affected the mobility of nucleotides U23 and U38, which are involved in a base-triple interaction in the complex. This report highlights the role of dynamics in specific molecular complex formation and demonstrates the ability of EPR spectroscopy to study interfacial dynamics of macromolecular complexes.

Down in the Paleochannels

NASA Image and Video Library

2015-11-27

This whole area, located in Solis Planum, is an interesting, tectonic terrain south of Noctis Labrynthus which generally slopes toward the south as seen by NASA Mars Reconnaissance Orbiter spacecraft. Transverse aeolian ridges -- or TAR -- are mysterious, wind-blown features that are intermediate in size between ripples and much larger sand dunes. Ripples form from hopping sand grains, and dunes form from sand grains being blown over longer distances. One hypothesis for TAR formation is that larger grains like pebbles are rolled on top of smaller ripples; then, finer dust settles into the cracks, "inflating" the pebbles, making the TAR larger than typical ripples. Looking between the TAR, one sees a network of ancient, beaten-up channels that were carved by water, lava, or both. This whole area is located in Solis Planum, an interesting, tectonic terrain south of Noctis Labrynthus which generally slopes toward the south. http://photojournal.jpl.nasa.gov/catalog/PIA20157

Machine-smoking studies of cigarette filter color to estimate tar yield by visual assessment and through the use of a colorimeter.

PubMed

Morton, Michael J; Williams, David L; Hjorth, Heather B; Smith, Jennifer H

2010-04-01

This paper explores using the intensity of the stain on the end of the filter ("filter color") as a vehicle for estimating cigarette tar yield, both by instrument reading of the filter color and by visual comparison to a template. The correlation of machine-measured tar yield to filter color measured with a colorimeter was reasonably strong and was relatively unaffected by different puff volumes or different tobacco moistures. However, the correlation of filter color to machine-measured nicotine yield was affected by the moisture content of the cigarette. Filter color, as measured by a colorimeter, was generally comparable to filter extraction of either nicotine or solanesol in its correlation to machine-smoked tar yields. It was found that the color of the tar stain changes over time. Panelists could generally correctly order the filters from machine-smoked cigarettes by tar yield using the intensity of the tar stain. However, there was considerable variation in the panelist-to-panelist tar yield estimates. The wide person-to-person variation in tar yield estimates, and other factors discussed in the text could severely limit the usefulness and practicality of this approach for visually estimating the tar yield of machine-smoked cigarettes. Copyright 2009 Elsevier Inc. All rights reserved.

Preliminary assessments of the occurrence and effects of utilization of sand and aggregate resources of the Louisiana inner shelf

USGS Publications Warehouse

Suter, J.R.; Mossa, J.; Penland, S.

1989-01-01

Louisiana is experiencing the most critical coastal erosion and land loss problem in the United States. Shoreline erosion rates exceed 6 m/yr in more than 80% of the Louisiana coastal zone and can be up to 50 m/yr in areas impacted by hurricanes. The barrier islands have decreased in area by some 40% since 1880. Land loss from coastal marshlands and ridgelands from both natural and human-induced processes is estimated to exceed 100 km2/yr. In response, a two-phase plan has been established, calling for barrier-island restoration and beach nourishment, both requiring large amounts of sand. The plan will be cost-effective only if sand can be found offshore in sufficient quantities close to project sites. To locate such deposits, the Louisiana Geological Survey is conducting an inventory of nearshore sand resources on the Louisiana continental shelf. Exploration for offshore sand deposits is conducted in two phases, with high-resolution seismic reflection profiling to locate potential sand bodies followed by vibracoring to confirm seismic intepretations and obtain samples for textural characterization. As part of the initial stages of the program, reconnaissance high-resolution seismic investigations of three areas of the continental shelf representing different stages in the evolutionary sequence of barrier shorelines were carried out. The Timbalier Islands, flanking barriers of the eroding Caminada-Moreau headland, contain potential sand resources associated with buried tidal and distributary channels. The Chandeleur Islands, a barrier-island arc, have potential offshore sands in the form of truncated spit and tidal inlet deposits, submerged beach ridges, and distributary channels. Trinity Shoal, an inner shelf shoal, is an offshore feature containing up to 2 ?? 109 m3 of material, most of which is probably fine sand. These reconnaissance surveys have demonstrated the occurrence of sand resources on the Louisiana continental shelf. Utilization of such deposits for

A case-control study of asphalt and tar exposure and lung cancer in minorities.

PubMed

McClean, Michael D; Kelsey, Karl T; Sison, Jennette D; Quesenberry, Charles P; Wrensch, Margaret R; Wiencke, John K

2011-11-01

Considerable controversy surrounds the carcinogenic potential of asphalt and tar. Since minority individuals may have had relatively high historical exposures, we investigated asphalt and tar exposure and lung cancer risk among African Americans and Latino Americans. We conducted a case-control study of lung cancer among African Americans and Latino Americans in the San Francisco Bay area (422 cases, 894 controls). A questionnaire was used to obtain detailed work histories and exposure information. Self-reported exposure to asphalt and tar as well as other factors (e.g., smoking, automobile exhaust, and asbestos) were evaluated as predictors of lung cancer risk. Potential effect modification by cytochrome P450 (CYP) 1A1 was also explored. Self-reported duration of exposure to asphalt and tar was associated with a statistically significant excess risk of lung cancer in the overall population (OR: 1.11, 95% CI: 1.01-1.22), evaluating risk per year of exposure. Years of exposure to automobile exhaust (OR: 1.02, 95% CI: 1.00-1.05) and asbestos (OR: 1.04, 95% CI: 1.02-1.06) were also associated with statistically significant elevations in risk. In Latino Americans, the lung cancer risks associated with polycyclic aromatic hydrocarbon-related exposures were consistently higher in the CYP1A1 wild-type subjects as compared to the variant genotype subjects, and the interaction was statistically significant for smoking and the CYP1A1 M2 polymorphism (P-value(interaction) = 0.02). These data are consistent with the literature suggesting that exposure to asphalt and tar may increase risk of lung cancer. However, it was not possible to separate the effects and asphalt and tar in this study. Copyright © 2011 Wiley Periodicals, Inc.

A Case-Control Study of Asphalt and Tar Exposure and Lung Cancer in Minorities

PubMed Central

McClean, Michael D.; Kelsey, Karl T.; Sison, Jennette D; Quesenberry, Charles P; Wrensch, Margaret R; Wiencke, John K.

2011-01-01

Objectives Considerable controversy surrounds the carcinogenic potential of asphalt and tar. Since minority individuals may have had relatively high historical exposures, we investigated asphalt and tar exposure and lung cancer risk among African Americans and Latino Americans. Methods We conducted a case-control study of lung cancer among African Americans and Latino Americans in the San Francisco Bay area (422 cases, 894 controls). A questionnaire was used to obtain detailed work histories and exposure information. Self-reported exposure to asphalt and tar as well as other factors (eg. smoking, automobile exhaust, and asbestos) were evaluated as predictors of lung cancer risk. Potential effect modification by cytochrome P450 (CYP) 1A1 was also explored. Results Self-reported duration of exposure to asphalt and tar was associated with a statistically significant excess risk of lung cancer in the overall population (OR: 1.11, 95%CI: 1.01–1.22), evaluating risk per year of exposure. Years of exposure to automobile exhaust (OR: 1.02, 95%CI: 1.00–1.05) and asbestos (OR: 1.04, 95%CI: 1.02–1.06) were also associated with statistically significant elevations in risk. In Latino Americans, the lung cancer risks associated with polycyclic aromatic hydrocarbon-related exposures were consistently higher in the CYP1A1 wildtype subjects as compared to the variant genotype subjects, and the interaction was statistically significant for smoking and the CYP1A1 M2 polymorphism (p-valueinteraction=0.02). Conclusions These data are consistent with the literature suggesting that exposure to asphalt and tar may increase risk of lung cancer. However, it was not possible to separate the effects and asphalt and tar in this study. PMID:21882217

Why do sand furrow distributions vary in the North Polar latitudes on Mars?

NASA Astrophysics Data System (ADS)

Bourke, Mary; McGaley-Towle, Zoe

2014-05-01

Sand dunes on Mars display geomorphic evidence of an active and dynamic sediment flux. Barchan dunes migrate, ripples move and the slipface morphology changes annually. Aeolian sediment transport is seasonally constrained and linked to cryogenic processes. Sand furrows are geomorphic features that are eroded into the surface of dunes. They form during sublimation of the seasonal carbon dioxide deposit which moves gas and sand through vents in the ice (cryo-venting) (Bourke, 2013). They are visible on the surface of dunes using the highest resolution images available for Mars. Previous work has noted that the distribution of furrows varies spatially both on individual dunes and at different Polar locations. Here we report on the preliminary findings of a mapping project that seeks to confirm this previous qualitative observation. In addition, we aim to explain the observed spatial and temporal variation in sand furrows on North Polar dunes. Ten polar sites that reflect a latitudinal range of 9.5º are being analysed. The HiRISE images were acquired between 16/2/2012 and 31/05/2012, over a period of 105 Earth days or 102 Sols. We have completed mapping of 1711 sand furrows in an 84 km2 area of sand dunes, i.e. at four of the ten sites. The data confirm that there is variability in the distribution of sand furrows in the Polar Region. While data from all ten sites will be required to fully test the assertion of a latitudinal control, it is worth noting that the two most northerly sites have a significantly higher density of furrows compared to the two lower latitude sites. As the seasonal ice thickness is known to increases pole-ward on Mars, our data suggest that effective furrow formation may be linked to ice deposit thickness. In particular, it suggests that a threshold in ice thickness must be crossed in order for effective cryo-venting to occur. Bourke, M.C., 2013. Sand Furrows: A new surface feature on Martian dunes, EGU, EGU2013-11859, Vienna.

Mineral magnetic characteristics of the late Quaternary coastal red sands of Bheemuni, East Coast (India)

NASA Astrophysics Data System (ADS)

Srivastava, Priyeshu; Sangode, S. J.; Parmar, Nikita; Meshram, D. C.; Jadhav, Priyanka; Singhvi, A. K.

2016-11-01

The voluminous red sand deposits of Bheemuni in the east coast of India provide record of coastal land-sea interaction during the late Quaternary climatic and eustatic oscillations. Limited information on the origin and depositional environments of these red sands and their chronology is available. We studied two inland to coast cross profiles from Bheemuni red sand deposits using mineral magnetism, color characteristics and Citrate-bicarbonate-dithionite (CBD) extractable pedogenic iron oxides over 23 horizons along with optically stimulated luminescence (OSL) chronology at 6 horizons. The oldest exposed bed had an optical age of 48.9 ± 1.7 ka. Differential ages between the two parallel sections (SOS = 48.9 ± 1.7 to 12.1 ± 0.3 ka and IMD = 29.3 ± 3.5 ka) suggest laterally shifting fluvial sedimentation. Both the profiles show significant amount of antiferromagnetic oxide (hematite) along with ferrimagnetic (magnetite/maghemite) mineral composition. The granulometric (/domain-) sensitive parameters (χFD, χARM, SIRM/χLF and χARM/χLF) indicate variable concentration of superparamagnetic (SP) and single domain (SD) particles between the two profiles. The higher frequency dependent and pedogenic magnetic susceptibilities (χFD and χpedo) in the younger (IMD) profile suggest enhanced pedogenesis under a warm-wet climate post 29.3 ka and also during Holocene. A combination of hard isothermal remanent magnetization (HIRM) and redness rating (RR) index indicates distinct but variable concentration of a) crystalline and b) poorly crystalline (pigmentary) hematites in both the profiles. We consider that the former (#a) is derived from hinterland red soils and possibly due to post-depositional diagenesis, and the latter (#b) precipitated from the dissolved iron under fluvial regime imparting the unique red coloration to Bheemuni sands. Partial to complete alteration of ferromagnesian minerals due to pedogenesis in hinterlands under warm-wet climate was therefore the

The linear relationship between cigarette tar and nicotine yields: regulatory implications for smoke constituent ratios.

PubMed

St Charles, F K; Cook, C J; Clayton, P M

2011-02-01

Cigarette smoke analyte yields are often expressed as ratios relative to tar or nicotine yields, usually to compare different products or to estimate human uptake of smoke in relation to nicotine uptake measurements. The method, however, can lead to distorted interpretations, especially in the case of ratios from ultra-low tar yield cigarettes. In brief, as tar yields decrease below the 5–6 mg per cigarette range, the tar-to-nicotine ratio (TNR) decreases rapidly in a non-linear fashion. If, however, the nicotine yield, rather than the ratio, is plotted versus the tar yield, the non-linearity disappears and a straight line is obtained, with a slight positive intercept for nicotine on the ordinate. Unlike the ratio, the slope appears to depend only on the concentration of the nicotine in the blend and does not appear to vary with smoking parameters such as puff volume, puff interval or length smoked or with cigarette design parameters such as length, circumference or the amount of filtration or filter ventilation. Therefore, such a slope is analogous to the TNR although, unlike that ratio, it is invariant. Even more simply, the concentration of the nicotine in the blend, at least for American blend-style cigarettes, provides a similar index.

Sand dunes on the central Delmarva Peninsula, Maryland and Delaware

USGS Publications Warehouse

Denny, Charles Storrow; Owens, James Patrick

1979-01-01

Inconspicuous ancient sand dunes are present in parts of the central Delmarva Peninsula, Maryland and Delaware. Many dunes are roughly V-shaped, built by northwest winds, especially on the east sides of some of the large rivers. On the uplands, the form and spacing of the dunes are variable. A surficial blanket composed mainly of medium and fine-grained sand-the Parsonsburg Sand-forms both the ancient dunes and the broad plains between the dunes. The sand that forms the dunes is massive and intensely burrowed in the upper part; traces of horizontal or slightly inclined bedding appear near the base. Quartz is the dominant mineral constituent of the sand. Microline is abundant in the very fine to fine sand fraction. The heavy-mineral assemblages (high zircon, tourmaline, rutile) are more mature than in most of the possible source rocks. The most abundant minerals in the clay-sized fraction are dioctahedral vermiculite, kaolinite, illite, montmorillonite, and gibbsite. The first four minerals are common in deposits of late Wisconsin and Holocene age. The gibbsite may be detrital, coming from weathered rocks of Tertiary age. The soil profile in the dune sand is weakly to moderately developed. At or near the base of the Parsonsburg Sand are peaty beds that range in age from about 30,000 to about 13,000 radiocarbon years B.P. Microfloral assemblages in the peaty beds suggest that the dunes on the uplands formed in a spruce parkland during the late Wisconsin glacial maximum. The river dunes may also be of late Wisconsin age, but could be Holocene.

Secondary ferroan dolomite rhombs in oil reservoirs, Chadra Sands, Gialo field, Libya

DOE Office of Scientific and Technical Information (OSTI.GOV)

Al-Shaieb, Z.; Shelton, J.W.

1978-03-01

Oil-productive, Oligocene Chadra sands in Gialo field, Libya, at depths of 600 to 750 m contain small dolomite rhombs. The rhombs are present as single crystals on detrital grains and as nonmosaic aggregates in pore space. The dolomite is calcium-rich and contains up to 10% iron but not measurable sodium or strontium. Total dissolved solids of produced interstitial water from the Chadra sand range from about 4,500 to 10,000 ppM. Introduction of fresh (meteoric) water into the Chadra sands, which were deposited in shallow-marine (shelf) environment, was responsible for formation of the dolomite rhombs. Iron in the dolomite rhombs wasmore » derived from alteration of galuconite.« less

Microbes in Beach Sands: Integrating Environment, Ecology and Public Health

PubMed Central

Whitman, Richard; Harwood, Valerie J.; Edge, Thomas A.; Nevers, Meredith; Byappanahalli, Muruleedhara; Vijayavel, Kannappan; Brandão, João; Sadowsky, Michael J.; Alm, Elizabeth Wheeler; Crowe, Allan; Ferguson, Donna; Ge, Zhongfu; Halliday, Elizabeth; Kinzelman, Julie; Kleinheinz, Greg; Przybyla-Kelly, Kasia; Staley, Christopher; Staley, Zachery; Solo-Gabriele, Helena M.

2014-01-01

SUMMARY Beach sand is a habitat that supports many microbes, including viruses, bacteria, fungi and protozoa (micropsammon). The apparently inhospitable conditions of beach sand environments belie the thriving communities found there. Physical factors, such as water availability and protection from insolation; biological factors, such as competition, predation, and biofilm formation; and nutrient availability all contribute to the characteristics of the micropsammon. Sand microbial communities include autochthonous species/phylotypes indigenous to the environment. Allochthonous microbes, including fecal indicator bacteria (FIB) and waterborne pathogens, are deposited via waves, runoff, air, or animals. The fate of these microbes ranges from death, to transient persistence and/or replication, to establishment of thriving populations (naturalization) and integration in the autochthonous community. Transport of the micropsammon within the habitat occurs both horizontally across the beach, and vertically from the sand surface and ground water table, as well as at various scales including interstitial flow within sand pores, sediment transport for particle-associated microbes, and the large-scale processes of wave action and terrestrial runoff. The concept of beach sand as a microbial habitat and reservoir of FIB and pathogens has begun to influence our thinking about human health effects associated with sand exposure and recreational water use. A variety of pathogens have been reported from beach sands, and recent epidemiology studies have found some evidence of health risks associated with sand exposure. Persistent or replicating populations of FIB and enteric pathogens have consequences for watershed/beach management strategies and regulatory standards for safe beaches. This review summarizes our understanding of the community structure, ecology, fate, transport, and public health implications of microbes in beach sand. It concludes with recommendations for future

Design-Based Peptidomimetic Ligand Discovery to Target HIV TAR RNA Using Comparative Analysis of Different Docking Methods.

PubMed

Fu, Junjie; Xia, Amy; Dai, Yao; Qi, Xin

2016-01-01

Discovering molecules capable of binding to HIV trans-activation responsive region (TAR) RNA thereby disrupting its interaction with Tat protein is an attractive strategy for developing novel antiviral drugs. Computational docking is considered as a useful tool for predicting binding affinity and conducting virtual screening. Although great progress in predicting protein-ligand interactions has been achieved in the past few decades, modeling RNA-ligand interactions is still largely unexplored due to the highly flexible nature of RNA. In this work, we performed molecular docking study with HIV TAR RNA using previously identified cyclic peptide L22 and its analogues with varying affinities toward HIV-1 TAR RNA. Furthermore, sarcosine scan was conducted to generate derivatives of CGP64222, a peptide-peptoid hybrid with inhibitory activity on Tat/TAR RNA interaction. Each compound was docked using CDOCKER, Surflex-Dock and FlexiDock to compare the effectiveness of each method. It was found that FlexiDock energy values correlated well with the experimental Kd values and could be used to predict the affinity of the ligands toward HIV-1 TAR RNA with a superior accuracy. Our results based on comparative analysis of different docking methods in RNA-ligand modeling will facilitate the structure-based discovery of HIV TAR RNA ligands for antiviral therapy.

Provenance and recycling of Arabian desert sand

NASA Astrophysics Data System (ADS)

Garzanti, Eduardo; Vermeesch, Pieter; Andò, Sergio; Vezzoli, Giovanni; Valagussa, Manuel; Allen, Kate; Kadi, Khalid; Al-Juboury, Ali

2013-04-01

This study seeks to determine the ultimate origin of aeolian sand in Arabian deserts by high-resolution petrographic and heavy-mineral techniques combined with zircon U-Pb geochronology. Point-counting is used here as the sole method by which unbiased volume percentages of heavy minerals can be obtained. A comprehensive analysis of river and wadi sands from the Red Sea to the Bitlis-Zagros orogen allowed us to characterize all potential sediment sources, and thus to quantitatively constrain provenance of Arabian dune fields. Two main types of aeolian sand can be distinguished. Quartzose sands with very poor heavy-mineral suites including zircon occupy most of the region comprising the Great Nafud and Rub' al-Khali Sand Seas, and are largely recycled from thick Lower Palaeozoic quartzarenites with very minor first-cycle contributions from Precambrian basement, Mesozoic carbonate rocks, or Neogene basalts. Instead, carbonaticlastic sands with richer lithic and heavy-mineral populations characterize coastal dunes bordering the Arabian Gulf from the Jafurah Sand Sea of Saudi Arabia to the United Arab Emirates. The similarity with detritus carried by the axial Tigris-Euphrates system and by transverse rivers draining carbonate rocks of the Zagros indicates that Arabian coastal dunes largely consist of far-travelled sand, deposited on the exposed floor of the Gulf during Pleistocene lowstands and blown inland by dominant Shamal northerly winds. A dataset of detrital zircon U-Pb ages measured on twelve dune samples and two Lower Palaeozoic sandstones yielded fourteen identical age spectra. The age distributions all show a major Neoproterozoic peak corresponding to the Pan-African magmatic and tectonic events by which the Arabian Shield was assembled, with minor late Palaeoproterozoic and Neoarchean peaks. A similar U-Pb signature characterizes also Jafurah dune sands, suggesting that zircons are dominantly derived from interior Arabia, possibly deflated from the Wadi al

Provenance and recycling of Arabian desert sand

NASA Astrophysics Data System (ADS)

Garzanti, Eduardo; Vermeesch, Pieter; Andò, Sergio; Vezzoli, Giovanni; Valagussa, Manuel; Allen, Kate; Kadi, Khalid A.; Al-Juboury, Ali I. A.

2013-05-01

This study seeks to determine the ultimate origin of aeolian sand in Arabian deserts by high-resolution petrographic and heavy-mineral techniques combined with zircon U-Pb geochronology. Point-counting is used here as the sole method by which unbiased volume percentages of heavy minerals can be obtained. A comprehensive analysis of river and wadi sands from the Red Sea to the Bitlis-Zagros orogen allowed us to characterize all potential sediment sources, and thus to quantitatively constrain provenance of Arabian dune fields. Two main types of aeolian sand can be distinguished. Quartzose sands with very poor heavy-mineral suites including zircon occupy most of the region comprising the Great Nafud and Rub' al-Khali Sand Seas, and are largely recycled from thick Lower Palaeozoic quartzarenites with very minor first-cycle contributions from Precambrian basement, Mesozoic carbonate rocks, or Neogene basalts. Instead, carbonaticlastic sands with richer lithic and heavy-mineral populations characterize coastal dunes bordering the Arabian Gulf from the Jafurah Sand Sea of Saudi Arabia to the United Arab Emirates. The similarity with detritus carried by the axial Tigris-Euphrates system and by transverse rivers draining carbonate rocks of the Zagros indicates that Arabian coastal dunes largely consist of far-travelled sand, deposited on the exposed floor of the Gulf during Pleistocene lowstands and blown inland by dominant Shamal northerly winds. A dataset of detrital zircon U-Pb ages measured on twelve dune samples and two Lower Palaeozoic sandstones yielded fourteen identical age spectra. The age distributions all show a major Neoproterozoic peak corresponding to the Pan-African magmatic and tectonic events by which the Arabian Shield was assembled, with minor late Palaeoproterozoic and Neoarchean peaks. A similar U-Pb signature characterizes also Jafurah dune sands, suggesting that zircons are dominantly derived from interior Arabia, possibly deflated from the Wadi al

FeS-coated sand for removal of arsenic(III) under anaerobic conditions in permeable reactive barriers

USGS Publications Warehouse

Han, Y.-S.; Gallegos, T.J.; Demond, A.H.; Hayes, K.F.

2011-01-01

Iron sulfide (as mackinawite, FeS) has shown considerable promise as a material for the removal of As(III) under anoxic conditions. However, as a nanoparticulate material, synthetic FeS is not suitable for use in conventional permeable reactive barriers (PRBs). This study developed a methodology for coating a natural silica sand to produce a material of an appropriate diameter for a PRB. Aging time, pH, rinse time, and volume ratios were varied, with a maximum coating of 4.0 mg FeS/g sand achieved using a pH 5.5 solution at a 1:4 volume ratio (sand: 2 g/L FeS suspension), three days of aging and no rinsing. Comparing the mass deposited on the sand, which had a natural iron-oxide coating, with and without chemical washing showed that the iron-oxide coating was essential to the formation of a stable FeS coating. Scanning electron microscopy images of the FeS-coated sand showed a patchwise FeS surface coating. X-ray photoelectron spectroscopy showed a partial oxidation of the Fe(II) to Fe(III) during the coating process, and some oxidation of S to polysulfides. Removal of As(III) by FeS-coated sand was 30% of that by nanoparticulate FeS at pH 5 and 7. At pH 9, the relative removal was 400%, perhaps due to the natural oxide coating of the sand or a secondary mineral phase from mackinawite oxidation. Although many studies have investigated the coating of sands with iron oxides, little prior work reports coating with iron sulfides. The results suggest that a suitable PRB material for the removal of As(III) under anoxic conditions can be produced through the deposition of a coating of FeS onto natural silica sand with an iron-oxide coating. ?? 2010 Elsevier Ltd.

Trouvelot Crater Deposit

NASA Image and Video Library

2002-12-04

Like many of the craters in the Oxia Palus region of Mars, Trouvelot Crater, shown in this NASA Mars Odyssey image, hosts an eroded, light-toned, sedimentary deposit on its floor. Compared with the much larger example in Becquerel Crater to the NE, the Trouvelot deposit has been so eroded by the scouring action of dark, wind-blown sand that very little of it remains. Tiny outliers of bright material separated from the main mass attest to the once, more really extensive coverage by the deposit. A similar observation can be made for White Rock, the best known example of a bright, crater interior deposit. The origin of the sediments in these deposits remains enigmatic but they are likely the result of fallout from ash or dust carried by the thin martian atmosphere. http://photojournal.jpl.nasa.gov/catalog/PIA04017

Sedimentology and composition of sands injected during the seismic crisis of May 2012 (Emilia, Italy): clues for source layer identification and liquefaction regime

NASA Astrophysics Data System (ADS)

Fontana, D.; Lugli, S.; Marchetti Dori, S.; Caputo, R.; Stefani, M.

2015-07-01

In May 2012 widespread sand blows formed along buried channels in the eastern sector of the Po Plain (Northern Italy) as a consequence of a series of seismic events with main shocks of Mw 6.1 and 5.9. At San Carlo (Ferrara) a trench dug a few week after the earthquakes exposed sand dikes cutting through an old Reno River channel-levee system that was diverted in the 18th century and was deposited starting from the 14th century (unit A). This sequence overlies a Holocene muddy floodplain deposits and contains scattered sandy channel deposits (unit B) and a Pleistocene channel sand unit (unit C). Sands with inverse and normal grading, concave layering and vertical lamination coexisting along the dikes suggest multiple rhythmic opening and closing of the fractures that were injected and filled by a slurry of sand during the compression pulses, and emptied during the extension phase. The pulse mechanism may have lasted for several minutes and formed well stratified sand volcanoes structures that formed at the top of the fractures. Sands from dikes and from the various units show well defined compositional fields from lithoarenitic to quartz-feldspar-rich compositions. Sands from the old Reno levee and channel fill (unit A) have abundant lithic fragments derived from the erosion of Apennine sedimentary carbonate and terrigenous successions. Composition of the sand filling the dikes show clear affinities with sand layers of the old Reno River channel (Unit A) and clearly differ from any sand from deeper Holocene and Pleistocene layers (Unit B and C), which are richer in quartz and feldspar and poorer in sedimentary lithic fragments. Sorting related to sediment flux variations did not apparently affect the sand composition across the sedimentary structures. Textural and compositional data indicate that the liquefaction processes originated from a relatively shallow source consisting of channel sands located within Unit A at 6.8.to 7.5 m depth.

Ubiquitous tar balls with a California-source signature on the shorelines of Prince William Sound, Alaska

USGS Publications Warehouse

Kvenvolden, K.A.; Hostettler, F.D.; Carlson, P.R.; Rapp, J.B.; Threlkeld, C.N.; Warden, A.

1995-01-01

Although the shorelines of Prince William Sound still bear traces of the 1989 Exxon Valdez oil spill, most of the flattened tar balls that can be found today on these shorelines are not residues of Exxon Valdez oil. Instead, the carbon-isotopic and hydrocarbon-biomarker signatures of 61 tar ball samples, collected from shorelines throughout the northern and western parts of the sound, are all remarkably similar and have characteristics consistent with those of oil products that originated from the Monterey Formation source rocks of California. The carbon-isotopic compositions of the tar balls are all closely grouped (??13CPDB = -23.7 ?? 0.2???), within the range found in crude oils from those rocks, but are distinct from isotopic compositions of 28 samples of residues from the Exxon Valdez oil spill (??13CPDB = -29.4 ?? 0.1???). Likewise, values for selected biomarker ratios in the tar balls are all similar but distinct from values of residues from the 1989 oil spill. Carbon-isotopic and biomarker signatures generally relate the tar balls to oil products used in Alaska before ???1970 for construction and pavements. How these tar balls with such similar geochemical characteristics became so widely dispersed throughout the northern and western parts of the sound is not known with certainty, but the great 1964 Alaska earthquake was undoubtedly an important trigger, causing spills from ruptured storage facilities of California-sourced asphalt and fuel oil into Prince William Sound.

Microplastic and tar pollution on three Canary Islands beaches: An annual study.

PubMed

Herrera, A; Asensio, M; Martínez, I; Santana, A; Packard, T; Gómez, M

2018-04-01

Marine debris accumulation was analyzed from three exposed beaches of the Canary Islands (Lambra, Famara and Las Canteras). Large microplastics (1-5mm), mesoplastics (5-25mm) and tar pollution were assessed twice a month for a year. There was great spatial and temporal variability in the Canary Island coastal pollution. Seasonal patterns differed at each location, marine debris concentration depended mainly of local-scale wind and wave conditions. The most polluted beach was Lambra, a remote beach infrequently visited. The types of debris found were mainly preproduction resin pellets, plastic fragments and tar, evidencing that pollution was not of local origin, but it cames from the open sea. The levels of pollution were similar to those of highly industrialized and contaminated regions. This study corroborates that the Canary Islands are an area of accumulation of microplastics and tar rafted from the North Atlantic Ocean by the southward flowing Canary Current. Copyright © 2017 Elsevier Ltd. All rights reserved.

Numerical simulation of vortex pyrolysis reactors for condensable tar production from biomass

DOE Office of Scientific and Technical Information (OSTI.GOV)

Miller, R.S.; Bellan, J.

1998-08-01

A numerical study is performed in order to evaluate the performance and optimal operating conditions of vortex pyrolysis reactors used for condensable tar production from biomass. A detailed mathematical model of porous biomass particle pyrolysis is coupled with a compressible Reynolds stress transport model for the turbulent reactor swirling flow. An initial evaluation of particle dimensionality effects is made through comparisons of single- (1D) and multi-dimensional particle simulations and reveals that the 1D particle model results in conservative estimates for total pyrolysis conversion times and tar collection. The observed deviations are due predominantly to geometry effects while directional effects frommore » thermal conductivity and permeability variations are relatively small. Rapid ablative particle heating rates are attributed to a mechanical fragmentation of the biomass particles that is modeled using a critical porosity for matrix breakup. Optimal thermal conditions for tar production are observed for 900 K. Effects of biomass identity, particle size distribution, and reactor geometry and scale are discussed.« less

Understanding the fate and transport of petroleum hydrocarbons from coal tar within gasholders.

PubMed

Coulon, Frédéric; Orsi, Roberto; Turner, Claire; Walton, Chris; Daly, Paddy; Pollard, Simon J T

2009-02-01

Coal tars have been identified as posing a threat to human health due to their toxic, mutagenic and carcinogenic characteristics. Workers involved in former gasholders decommissioning are potentially exposed to relevant concentrations of volatile and semi-volatile hydrocarbons upon opening up derelict tanks and during tar excavation/removal. While information on contaminated sites air-quality and its implications on medium-long term exposure is available, acute exposure issues associated with the execution of critical tasks are less understood. Calculations indicated that the concentration of a given contaminant in the gasholder vapour phase only depends on the coal tar composition, being only barely affected by the presence of water in the gasholder and the tar volume/void space ratio. Fugacity modelling suggested that risk-critical compounds such as benzene, naphthalene and other monocyclic and polycyclic aromatic hydrocarbons may gather in the gasholder air phase at significant concentrations. Gasholder emissions were measured on-site and compared with the workplace exposure limits (WELs) currently in use in UK. While levels for most of the toxic compounds were far lower than WELs, benzene air-concentrations where found to be above the accepted threshold. In addition due to the long exposure periods involved in gasholder decommissioning and the significant contribution given by naphthalene to the total coal tar vapour concentration, the adoption of a WEL for naphthalene may need to be considered to support operators in preventing human health risk at the workplace. The Level I fugacity approach used in this study demonstrated its suitability for applications to sealed environments such as gasholders and its further refining could provide a useful tool for land remediation risk assessors.

DeepMirTar: a deep-learning approach for predicting human miRNA targets.

PubMed

Wen, Ming; Cong, Peisheng; Zhang, Zhimin; Lu, Hongmei; Li, Tonghua

2018-06-01

MicroRNAs (miRNAs) are small noncoding RNAs that function in RNA silencing and post-transcriptional regulation of gene expression by targeting messenger RNAs (mRNAs). Because the underlying mechanisms associated with miRNA binding to mRNA are not fully understood, a major challenge of miRNA studies involves the identification of miRNA-target sites on mRNA. In silico prediction of miRNA-target sites can expedite costly and time-consuming experimental work by providing the most promising miRNA-target-site candidates. In this study, we reported the design and implementation of DeepMirTar, a deep-learning-based approach for accurately predicting human miRNA targets at the site level. The predicted miRNA-target sites are those having canonical or non-canonical seed, and features, including high-level expert-designed, low-level expert-designed, and raw-data-level, were used to represent the miRNA-target site. Comparison with other state-of-the-art machine-learning methods and existing miRNA-target-prediction tools indicated that DeepMirTar improved overall predictive performance. DeepMirTar is freely available at https://github.com/Bjoux2/DeepMirTar_SdA. lith@tongji.edu.cn, hongmeilu@csu.edu.cn. Supplementary data are available at Bioinformatics online.

Microbial shaping of wrinkle structures in siliciclastic deposits

NASA Astrophysics Data System (ADS)

Bosak, T.; Mariotti, G.; Pruss, S. B.; Perron, J.; O'Grady, M.

2013-12-01

Wrinkle structures are millimeter- to centimeter-scale elongated or reticulate sedimentary structures that resemble symmetric ripples. Sharp-crested and flat-topped wrinkle structures up to 1 cm wide occur on numerous bedding planes in the Neoproterozoic and Cambrian, as well as in some Archean and Phanerozoic siliciclastic deposits. Because similar, but unlithified structures occur in some modern, microbially-colonized sands, wrinkle structures are typically interpreted as microbially induced sedimentary structures. However, it is unclear if physical processes, such as the motion of suspended sand grains, can produce similar features in sand even before microbial colonization. We introduced mat fragments to the surface of silica sand in wave tanks and generated sharp-crested, flat-topped and pitted wrinkle structures. The abrasion of the sandy surface by rolling, low density, millimeter-size fragments of microbial mats produces wrinkle structures at extremely weak orbital velocities that cannot move sand grains in the absence of light particles. Wrinkle structures form in a few hours and can become colonized by microbial mats within weeks. Thus, wrinkle structures are patterns formed by microbially mediated sand motion at low orbital velocities in the absence of bioturbation. Once formed, wrinkle structures can be colonized and stabilized by microbial mats, but the shape of these mats does not dictate the shape of wrinkle structures. These experiments bolster the interpretation of wrinkle structures as morphological signatures of organic particles and early life in Archean and Proterozoic siliciclastic deposits.

Galveston Island, Texas, Sand Management Strategies

DTIC Science & Technology

2016-07-01

should be a component of any final design strategy. Not only is construction of a dry berm along the eastern end of the seawall a high priority, but it...they erode sand from the upper part of the beach (the part that is normally dry : the dune, the berm and the foreshore slope) and deposit it within...beach in Dade County: Its impact on the community. Papers Presented at Annual Conferences on Beach Preservation, (1984 and 1985), 114–121

Human immunodeficiency virus type 1 LTR TATA and TAR region sequences required for transcriptional regulation.

PubMed Central

Garcia, J A; Harrich, D; Soultanakis, E; Wu, F; Mitsuyasu, R; Gaynor, R B

1989-01-01

The human immunodeficiency virus (HIV) type 1 LTR is regulated at the transcriptional level by both cellular and viral proteins. Using HeLa cell extracts, multiple regions of the HIV LTR were found to serve as binding sites for cellular proteins. An untranslated region binding protein UBP-1 has been purified and fractions containing this protein bind to both the TAR and TATA regions. To investigate the role of cellular proteins binding to both the TATA and TAR regions and their potential interaction with other HIV DNA binding proteins, oligonucleotide-directed mutagenesis of both these regions was performed followed by DNase I footprinting and transient expression assays. In the TATA region, two direct repeats TC/AAGC/AT/AGCTGC surround the TATA sequence. Mutagenesis of both of these direct repeats or of the TATA sequence interrupted binding over the TATA region on the coding strand, but only a mutation of the TATA sequence affected in vivo assays for tat-activation. In addition to TAR serving as the site of binding of cellular proteins, RNA transcribed from TAR is capable of forming a stable stem-loop structure. To determine the relative importance of DNA binding proteins as compared to secondary structure, oligonucleotide-directed mutations in the TAR region were studied. Local mutations that disrupted either the stem or loop structure were defective in gene expression. However, compensatory mutations which restored base pairing in the stem resulted in complete tat-activation. This indicated a significant role for the stem-loop structure in HIV gene expression. To determine the role of TAR binding proteins, mutations were constructed which extensively changed the primary structure of the TAR region, yet left stem base pairing, stem energy and the loop sequence intact. These mutations resulted in decreased protein binding to TAR DNA and defects in tat-activation, and revealed factor binding specifically to the loop DNA sequence. Further mutagenesis which inverted

Elevated radionuclide concentrations in heavy mineral-rich beach sands in the Cox's Bazar region, Bangladesh and related possible radiological effects.

PubMed

Zaman, Mashrur; Schubert, Michael; Antao, Sytle

2012-01-01

The study focuses on elevated levels of environmental radioactivity present in heavy mineral deposits located along a 120-km coastal section of Cox's Bazar on the eastern panhandle of Bangladesh. The deposits are situated in or at sand dunes located on the recent beach (foredune area) or in attached paleo-beach areas (backdune area). This study investigates activity concentrations in bulk beach sands (six representative samples) and in five mineral fractions separated from the beach sands in order to assess potential radio-ecological effects and the possible use of the mineral deposits as a source for uranium and thorium. The bulk beach sands and individual mineral fractions were analysed by gamma-ray spectroscopy. The activity concentrations of U-238, U-235, Th-232 and K-40 in the bulk beach sand samples were found to be considerably high and positively correlated to the concentration of heavy minerals in the sand. In the mineral fractions, the highest activity concentrations were found in the zircon fraction followed by garnet, rutile, ilmenite and magnetite. The determination of (i) the radium activity, (ii) several radiation hazard indices and (iii) adsorbed and effective gamma doses allowed to assess the related exposure of the environment and the local population to elevated radioactivity. It becomes evident from the present data that (1) if raw sands or mineral fractions mined in the study area are used for building purposes or industrial use, their activity concentrations have to be considered from a radio-ecological perspective and (2) if mining and processing of the minerals is being considered, uranium and thorium may become strategically significant by-products.

Airflow Dynamics and Sand Transport over a Coastal Foredune with Large Woody Debris.

NASA Astrophysics Data System (ADS)

Grilliot, M. J.; Walker, I. J.; Bauer, B. O.

2016-12-01

Airflow dynamics and sand transport patterns over beach-foredune systems are complex due to the effects of topographic forcing and varied surface roughness elements. The role of large woody debris (LWD) as a roughness element in foredune dynamics is understudied compared to the effects of plant cover. Unlike plants, non-porous objects like LWD impose bluff body effects and induce secondary flow circulation that varies with LWD size, density, and arrangement. It is hypothesized that modified flow patterns over LWD can influence beach-dune sediment budgets and dune geometry via changes to mean near-surface flow patterns, turbulence, sand transport pathways and sedimentation patterns. In turn, LWD may act as an accretion anchor and store appreciable amounts of aeolian sand that subsequently may provide an enhanced buffer against coastal and/or wind erosion. This study examines turbulent airflow dynamics and related sand transport patterns for oblique onshore flow conditions over a mesotidal beach and scarped dune on Calvert Island, British Columbia, Canada. Abundant exposed LWD fronting the foredune enhances turbulent Reynolds stress (RS) and turbulence intensity (TI) near the surface. During low, yet competent wind speeds (6.54 m s-1), RS and TI are not competent enough in the sheltered flow regions within the LWD matrix and sediment deposition occurs. However, small zones of localized acceleration were observed with sand transport. Higher wind speeds, well above the entrainment threshold, increase RS and TI over LWD relative to the beach, facilitating sediment transport through and over the LWD matrix, with localized pockets of deposition in sheltered areas. The majority of LWD deposits on beaches in the region are anthropogenic logging debris and are known to be decreasing since the 1950s, but likely earlier. Thus, it is important to understand how non-porous roughness elements, like LWD, affect beach-dune sediment budgets and evolution, particularly in light of

Constraints on the age of the Great Sand Dunes, Colorado, from subsurface stratigraphy and OSL dates

USGS Publications Warehouse

Madole, Richard F.; Mahan, Shannon; Romig, Joseph H.; Havens, Jeremy C.

2013-01-01

The age of the Great Sand Dunes has been debated for nearly 150 yr. Seven ages ranging from Miocene to late Holocene have been proposed for them. This paper presents new information—chiefly subsurface stratigraphic data, OSL dates, and geomorphic evidence—that indicates that the Great Sand Dunes began to form in the latter part of the middle Pleistocene. The dunes overlie a thick wedge of piedmont-slope deposits, which in turn overlies sediment of Lake Alamosa, a paleolake that began to drain about 440 ka. The wedge of piedmont-slope deposits extends westward for at least 23 km and is as much as 60 m thick at a distance of 10 km from the Sangre de Cristo Range. Ostracodes from one well indicate that the eastern shoreline of Lake Alamosa extended to within 4.3 km of where the Great Sand Dunes eventually formed. The time represented by the wedge of piedmont-slope deposits is not known exactly, but the wedge post-dates 440 ka and was in place prior to 130 ka because by then the dunes overlying it were sufficiently close and tall enough to obstruct streams draining from the Sangre de Cristo Range.

Prediction of Liquefaction Potential of Dredge Fill Sand by DCP and Dynamic Probing

DOE Office of Scientific and Technical Information (OSTI.GOV)

Alam, Md. Jahangir; Azad, Abul Kalam; Rahman, Ziaur

2008-07-08

From many research it is proved that liquefaction potential of sand is function of mainly relative density and confining pressure. During routine site investigations, high-quality sampling and laboratory testing of sands are not feasible because of inevitable sample disturbance effects and budgetary constraints. On the other hand quality control of sand fill can be done by determining in situ density of sand in layer by layer which is expensive and time consuming. In this paper TRL DCP (Transportation Research Laboratory Dynamic Cone Penetration) and DPL (Dynamic Probing Light) are calibrated to predict the relative density of sand deposit. For thismore » purpose sand of known relative density is prepared in a calibration chamber which is a mild steel cylinder with diameter 0.5 m and height 1.0 m. Relative density of sand is varied by controlling height of fall and diameter of hole of sand discharge bowl. After filling, every time DPL and DCP tests are performed and for every blow the penetration of cone is recorded. N10 is then calculated from penetration records. Thus a database is compiled where N10 and relative densities are known. A correlation is made between N{sub 10} and relative density for two types of sand. A good correlation of N{sub 10} and relative density is found.« less

Evaluation of Durability Parameters of Concrete with Manufacture Sand and River Sand

NASA Astrophysics Data System (ADS)

Sangoju, Bhaskar; Ramesh, G.; Bharatkumar, B. H.; Ramanjaneyulu, K.

2017-09-01

Most of the states in our country have banned sand quarrying from the river beds, causing a scarcity of natural river sand for the construction sector. Manufacture sand (M-sand) is one of the alternate solutions to replace the river sand (R-sand) in concrete. The main aim of the present study is to evaluate the durability parameters of concrete with M-sand when compared to that of concrete with R-sand. Corrosion of reinforcement is one of the main deteriorating mechanisms of reinforced concrete due to the ingress of chloride ions or carbon-di-oxide. For comparative evaluation of durability parameters, accelerated tests such as Rapid Chloride Permeability Test, Rapid Chloride Migration Test and accelerated carbonation test were carried out on specimens of R-sand and M-sand. All tests were carried out after 90 days of casting. Test results reveal that the durability parameters of the concrete with M-sand in chloride induced environment is relatively better than that of concrete with R-sand and hence is recommended to use M-sand as a replacement to R-sand.

Upgrading producer gas quality from rubber wood gasification in a radio frequency tar thermocatalytic treatment reactor.

PubMed

Anis, Samsudin; Zainal, Z A

2013-12-01

This study focused on improving the producer gas quality using radio frequency (RF) tar thermocatalytic treatment reactor. The producer gas containing tar, particles and water was directly passed at a particular flow rate into the RF reactor at various temperatures for catalytic and thermal treatments. Thermal treatment generates higher heating value of 5.76 MJ Nm(-3) at 1200°C. Catalytic treatments using both dolomite and Y-zeolite provide high tar and particles conversion efficiencies of about 97% on average. The result also showed that light poly-aromatic hydrocarbons especially naphthalene and aromatic compounds particularly benzene and toluene were still found even at higher reaction temperatures. Low energy intensive RF tar thermocatalytic treatment was found to be effective for upgrading the producer gas quality to meet the end user requirements and increasing its energy content. Copyright © 2013 Elsevier Ltd. All rights reserved.

Determination of the conformational ensemble of the TAR RNA by X-ray scattering interferometry

PubMed Central

Walker, Peter

2017-01-01

Abstract The conformational ensembles of structured RNA's are crucial for biological function, but they remain difficult to elucidate experimentally. We demonstrate with HIV-1 TAR RNA that X-ray scattering interferometry (XSI) can be used to determine RNA conformational ensembles. X-ray scattering interferometry (XSI) is based on site-specifically labeling RNA with pairs of heavy atom probes, and precisely measuring the distribution of inter-probe distances that arise from a heterogeneous mixture of RNA solution structures. We show that the XSI-based model of the TAR RNA ensemble closely resembles an independent model derived from NMR-RDC data. Further, we show how the TAR RNA ensemble changes shape at different salt concentrations. Finally, we demonstrate that a single hybrid model of the TAR RNA ensemble simultaneously fits both the XSI and NMR-RDC data set and show that XSI can be combined with NMR-RDC to further improve the quality of the determined ensemble. The results suggest that XSI-RNA will be a powerful approach for characterizing the solution conformational ensembles of RNAs and RNA-protein complexes under diverse solution conditions. PMID:28108663

Determination of the conformational ensemble of the TAR RNA by X-ray scattering interferometry.

PubMed

Shi, Xuesong; Walker, Peter; Harbury, Pehr B; Herschlag, Daniel

2017-05-05

The conformational ensembles of structured RNA's are crucial for biological function, but they remain difficult to elucidate experimentally. We demonstrate with HIV-1 TAR RNA that X-ray scattering interferometry (XSI) can be used to determine RNA conformational ensembles. X-ray scattering interferometry (XSI) is based on site-specifically labeling RNA with pairs of heavy atom probes, and precisely measuring the distribution of inter-probe distances that arise from a heterogeneous mixture of RNA solution structures. We show that the XSI-based model of the TAR RNA ensemble closely resembles an independent model derived from NMR-RDC data. Further, we show how the TAR RNA ensemble changes shape at different salt concentrations. Finally, we demonstrate that a single hybrid model of the TAR RNA ensemble simultaneously fits both the XSI and NMR-RDC data set and show that XSI can be combined with NMR-RDC to further improve the quality of the determined ensemble. The results suggest that XSI-RNA will be a powerful approach for characterizing the solution conformational ensembles of RNAs and RNA-protein complexes under diverse solution conditions. © The Author(s) 2017. Published by Oxford University Press on behalf of Nucleic Acids Research.

Hurricane Sandy washover deposits on Fire Island, New York

USGS Publications Warehouse

La Selle, SeanPaul M.; Lunghino, Brent D.; Jaffe, Bruce E.; Gelfenbaum, Guy; Costa, Pedro J.M.

2017-02-16

Washover deposits on Fire Island, New York, from Hurricane Sandy in 2012 were investigated a year after the storm to document the sedimentary characteristics of hurricane washover features. Sediment data collected in the field includes stratigraphic descriptions and photos from trenches, bulk sediment samples, U-channels, and gouge and push cores. Samples and push cores were further analyzed in the laboratory for grain size, density variations using x-ray computed tomography (CT), and surface microtexture using a scanning electron microscope (SEM). Elevation profiles of washover features were measured using Differential Global Positioning System (DGPS) with Real Time Kinematic processing. The DGPS elevations were compared to lidar (light detection and ranging) data from pre- and post-Sandy surveys to assess the degree to which washover deposit thicknesses changed within the year following deposition. Hurricane Sandy washover deposits as much as 1 meter thick were observed in trenches. Initial results show that the upper parts of the deposits have been reworked significantly in some places by wind, but there are still areas where the deposits are almost entirely intact. Where mostly intact, the washover deposits consist of massive or weakly laminated sand near the base, overlain by more strongly laminated sands.

Regional aeolian dynamics and sand mixing in the Gran Desierto - Evidence from Landsat Thematic Mapper images

NASA Technical Reports Server (NTRS)

Blount, Grady; Greeley, Ronald; Christensen, Phillip R.; Smith, Milton O.; Adams, John B.

1990-01-01

Mesoscale mapping of spatial variations in sand composition of the Gran Desierto (Sonora, Mexico) was carried out on multispectral Landsat TM images of this region, making it possible to examine the dynamic development of sand sheets and dunes. Compositions determined from remote imagery were found to agree well with samples from selected areas. The sand populations delineated were used to describe the sediment source areas, transport paths, and deposition sites. The image analysis revealed important compositional variations aver large areas that were not readily apparent in the field data.

The geology of the Florida land-pebble phosphate deposits

USGS Publications Warehouse

Cathcart, J.B.; Blade, L.V.; Davidson, D.F.; Ketner, K.B.

1952-01-01

The land-pebble phosphate district is on the Gulf Coastal Plain of Florida. The phosphate deposits are in the Bone Valley formation, dated Pliocene by most writers. These strata overlie the Miocene Hawthorn formation and are overlain by consolidated sands 3 to 20 feet thick. The minable phosphate deposits, called “matrix” in the district, range from a featheredge to about 50 feet in thickness and consist of phosphatic pellets and nodules, quartz sand, and montmorillonitic clay in about equal proportions. Locally the matrix displays cross-bedding and horizontal laminations, but elsewhere it is structureless. The phosphorite particles, composed largely of carbonate-fluorapatite, range in diameter from less than 0.1 mm to about 60 cm and in P2O5 content from 30 to 36 percent. Coarse-pebble deposits, containing 30 to 34 percent P2O5 are found mainly on basement highs; and fine-pebble deposits, containing 32 to 36 percent P2O5 are, are found in basement lows. Deposits in the northern part of the field contain more phosphate particles and their P2O5 content is higher than those in the southern part. The upper part of the phosphatic strata is leached to an advanced degree and consists of quartz sand and clay-sized particules of pseudowavellite and wavellite. The leached zone ranges in thickness from a featheredge to 60 feet. The origin of the land-pebble deposits is incompletely known. Possible modes of origin are a residuum of Miocene age, or a reworked residuum of Pliocene or Quaternary age.

Design and Verification of Blast Densification for Highway Embankments of Liquefiable Sands

DOT National Transportation Integrated Search

2012-10-26

As part of a larger effort to investigate the effects of blast densification on the properties and : behavior of compacted sand deposits, this study presents a procedure for replicating in the : laboratory the occluded gas bubbles believed to exist i...

Coastal eolian sand-ramp development related to paleo-sea-level changes during the Latest Pleistocene and Holocene (21–0 ka) in San Miguel Island, California, U.S.A.

USGS Publications Warehouse

Peterson, Curt D.; Erlandson, Jon M.; Stock, Errol; Hostetler, Steven W.; Price, David M.

2017-01-01

Coastal eolian sand ramps (5–130 m elevation) on the northern slope (windward) side of the small San Miguel Island (13 km in W-E length) range in age from late Pleistocene to modern time, though a major hiatus in sand-ramp growth occurred during the early Holocene marine transgression (16–9 ka). The Holocene sand ramps (1–5 m measured thicknesses) currently lack large dune forms, thereby representing deflated erosional remnants, locally covering thicker late Pleistocene sand-ramp deposits. The ramp sand was initially supplied from the adjacent island-shelf platform, extending about 20 km north of the present coastline. The sand-ramp deposits and interbedded loess soils were 14C dated using 112 samples from 32 archaeological sites and other geologic sections. Latest Pleistocene sand ramps (66–18 ka) were derived from across-shelf eolian sand transport during marine low stands. Shoreward wave transport supplied remobilized late Pleistocene sand from the inner shelf to Holocene beaches, where dominant NW winds supplied sand to the sand ramps. The onset dates of the sand-ramp deposition in San Miguel are 7.2 ± 1.5 ka (sample n = 14). The internal strata dates in the vertically accreting sand ramps are 3.4 ± 1.7 ka (n = 34). The sand ramps in San Miguel show wide-scale termination of sand supply in the latest Holocene time. The sand-ramp top dates or burial dates are 1.7 ± 0.9 ka (n = 28). The latest Holocene sand ramps are truncated along most of the island's northern coastline, indicating recent losses of nearshore sand reserves to onshore, alongshore, and, possibly, offshore sand sinks. The truncated sand ramps in San Miguel Island and in other sand-depleted marine coastlines provide warnings about future beach erosion and/or shoreline retreat from accelerated sea-level rise accompanying predicted global warming.

Sand transportation and reverse patterns over leeward face of sand dune

NASA Astrophysics Data System (ADS)

Jiang, Hong; Dun, Hongchao; Tong, Ding; Huang, Ning

2017-04-01

Sand saltation has complex interactions with turbulent flow and dune form. Most models of wind-blown sand consider ideal circumstances such as steady wind velocity and a flat surface, and the bulk of data on wind flow and sand transport over an individual dune has focused mostly on the influence of dune shape or inter-dune space on the wind flow, neglecting the effect of morphology on sand saltation, particularly airflow and sand transportation over the leeward slope. Wind flow structures over the leeward slope of sand dunes have a fundamental influence on the organization of sand dunes. In order to understand sand dune dynamics, lee face airflow and sediment transportation should be paid more attention. Previous field observations could not measure turbulent flow structure well because of the limited observation points and the influence of experiment structure on wind field. In addition, the reverse sand particles over leeward face could not be collected by sand trap in field. Numerous field observations could not measure turbulent flow structure because of the limited observation points and the influence of experimental structures on the wind field. In addition, the reverse transport of sand particles over leeward face could not be collected by sand traps in field. Therefore, this paper aims to investigate the turbulent flow structure and sand transport pattern over the leeward slope. A numerical model of sand saltation over slope terrain is constructed, which also considers the coupling effects between air flow and sand particles. The large eddy simulation method is used to model turbulent flow. Sand transport is simulated by tracking the trajectory of each sand particle. The results show that terrain significantly alters the turbulent air flow structure and wind-blown sand movement, especially over the leeward slope. Here, mass flux increases initially and then decreases with height in the reversed flow region in the direction of wind flow, and the mass flux

Shoreline erosion and decadal sediment accumulation in the Tar-Pamlico estuary, North Carolina, USA: A source-to-sink analysis

NASA Astrophysics Data System (ADS)

Eulie, Devon O.; Corbett, D. Reide; Walsh, J. P.

2018-03-01

Estuaries contain vital habitats and it is important to understand how these areas respond to human activities and natural processes such as sea-level rise and wave attack. As estuarine shorelines erode or become modified with hard structures, there is potential for significantly altering the availability of sediment and the filling of coastal systems. This study used a source-to-sink approach and quantified rates of shoreline erosion in the Tar-Pamlico sub-estuary, a tributary of the larger Albemarle-Pamlico Estuarine System (APES). The average shoreline change rate (SCR) determined using an end-point method was -0.5 ± 0.9 m yr-1 for the Tar-Pamlico. Incorporating bulk density estimates, this contributes 0.6 × 105 tons of fine sediment to the system annually, or after accounting for fluvial input, about 40% of the total sediment supply to the sub-estuary. The role of the Tar-Pamlico as a sink for these sediments was addressed using the radionuclide tracers 210Pb and 137Cs. Radionuclide activities and sediment accumulation rates identified several depositional regions, in particular in the middle of the estuary. Linear sediment accumulation rates ranged from 0.10 ± 0.02 to 0.38 ± 0.02 g cm-2 yr-1, and total storage of fine sediment in the system was 1.6 × 105 t yr-1. It was not possible to confidently discern a change in the rate of shoreline erosion or seabed accumulation. A preliminary budget for fine sediments (grain-size <63 μm) was then calculated to compare erosional sources with sedimentary sinks. Almost all (∼93.0%) of the fine sediment entering the system was accumulated and stored, while only about 7.0% was exported to Pamlico Sound.

SULFUR TOLERANT CATALYSTS FOR BIOMASS TAR REMOVAL - PHASE I

EPA Science Inventory

In this Small Business Innovation Research (SBIR) project, NexTech Materials proposes a catalytic reforming approach to remove waste tar from gasified biomass on nickel-based catalysts. Biomass gasification is a potential renewable route to producing electricity, liquid fue...

On the origin and age of the Great Sand Dunes, Colorado

USGS Publications Warehouse

Madole, R.F.; Romig, J.H.; Aleinikoff, J.N.; VanSistine, D.P.; Yacob, E.Y.

2008-01-01

Over the past 100??yr, several hypotheses have been proposed for the origin and age of the Great Sand Dunes. These hypotheses differ widely in the descriptions of dune morphometry, the immediate source of eolian sand, and when sand transport occurred. The primary purpose of this paper is to evaluate these hypotheses and, where warranted, to present new ideas about the origin and age of the Great Sand Dunes. To evaluate the previous hypotheses, we had to develop more detailed information about the surficial geology of the northern San Luis Valley. Thus, we mapped the surficial geology of an area extending several tens of kilometers north, south, and west of the Great Sand Dunes and examined subsurface stratigraphy in more than 200 wells and borings. In addition, we used relative-dating criteria and several radiocarbon and OSL ages to establish the chronology of surficial deposits, and we determined the U-Pb ages of detrital zircons to obtain information about the sources of the sand in the Great Sand Dunes. The first principal finding of this study is that the lower part of the closed basin north of the Rio Grande, referred to here as the sump, is the immediate source of the sand in the Great Sand Dunes, rather than the late Pleistocene flood plain of the Rio Grande (the most widely accepted hypothesis). A second principal finding is that the Great Sand Dunes are older than late Pleistocene. They postdate the draining of Lake Alamosa, which began ??? 440??ka, and predate the time when streams draining the west flank of the Sangre de Cristo Mountains were deflected by incipient dunes that formed near the mountain front. Geomorphic and stratigraphic evidence indicate that this deflection occurred prior to the end of the next to last glaciation (Bull Lake), i.e., prior to ??? 130??ka.

Late Holocene eolian activity in the mineralogically mature Nebraska Sand Hills

USGS Publications Warehouse

Muhs, D.R.; Stafford, Thomas W.; Swinehart, J.B.; Cowherd, S.D.; Mahan, S.A.; Bush, C.A.; Madole, R.F.; Maat, P.B.

1997-01-01

The age of sand dunes in the Nebraska Sand Hills has been controversial, with some investigators suggesting a full-glacial age and others suggesting that they were last active in the late Holocene. New accelerator mass spectrometry radiocarbon ages of unaltered bison bones and organic-rich sediments suggest that eolian sand deposition occurred at least twice in the past 3000 14C yr B.P. in three widely separated localities and as many as three times in the past 800 14C yr at three other localities. These late Holocene episodes of eolian activity are probably the result of droughts more intense than the 1930s "Dust Bowl" period, based on independent Great Plains climate records from lake sediments and tree rings. However, new geochemical data indicate that the Nebraska Sand Hills are mineralogically mature. Eolian sands in Nebraska have lower K-feldspar (and K2O, Rb, and Ba) contents than most possible source sediments and lower K-feldspar contents than dunes of similar age in Colorado. The most likely explanation for mineralogical maturity is reduction of sand-sized K-feldspar to silt-sized particles via ballistic impacts due to strong winds over many cycles of eolian activity. Therefore, dunes of the Nebraska Sand Hills must have had a long history, probably extending over more than one glacial-interglacial cycle, and the potential for reactivation is high, with or without a future greenhouse warming. ?? 1997 University of Washington.

Connecting onshore and offshore near-surface geology: Delaware's sand inventory project

USGS Publications Warehouse

Ramsey, K.W.; Jordan, R.R.; Talley, J.H.

1999-01-01

Beginning in 1988, the Delaware Geological Survey began a program to inventory on-land sand resources suitable for beach nourishment. The inventory included an assessment of the native beach textures using existing data and developing parameters of what would be considered suitable sand textures for Delaware's Atlantic beaches. An assessment of the economics of on-land sand resources was also conducted, and it was determined that the cost of the sand was competitive with offshore dredging costs. In addition, the sand resources were put into a geologic context for purposes of predicting which depositional environments and lithostratigraphic units were most likely to produce suitable sand resources. The results of the work identified several suitable on-land sand resource areas in the Omar and Beaverdam formations that were deposited in barrier-tidal delta and fluvial-estuarine environments, respectively. The identified on-land resources areas have not been utilized due to difficulties of truck transport and development pressures in the resource areas. The Delaware Geological Survey's participation in years 8, 9, and 10 of the Continental Margins Program was developed to extend the known resource areas onshore to offshore Delaware in order to determine potential offshore sand resources for beach nourishment. Years 8 and 9 involved primarily the collection of all available data on the offshore geology. These data included all seismic lines, surface grab samples, and cores. The data were filtered for those that had reliable locations and geologic information that could be used for geologic investigations. Year 10 completed the investigations onshore by construction of a geologic cross-section from data along the coast of Delaware from Cape Henlopen to Fenwick. This cross section identified the geologic units and potential sand resource bodies as found immediately along the coast. These units and resources are currently being extended offshore and tied to known and

Chronology and geochemistry of late Holocene eolian deposits in the Brandon Sand Hills, Manitoba, Canada

USGS Publications Warehouse

Wolfe, S.A.; Muhs, D.R.; David, P.P.; McGeehin, J.P.

2000-01-01

Accelerator mass spectrometry and conventional radiocarbon age determinations of organic matter from paleosols indicate that the Brandon Sand Hills area of southern Manitoba has been subjected to recurrent intervals of eolian activity in the past 5000 years. Although precise regional correlations are precluded by dating uncertainties, periods of most notable paleosol development occurred around 2300 to 2000, 1400 to 1000, and 600 to 500 cal yr BP with eolian activity occurring before and after each of these periods. Episodes of eolian activity may correspond to periods of regional drought, whereas paleosols mark periods of increased moisture availability and stabilization by vegetation. The geochemistry of the eolian sands, paleosols and source sediments indicates that partial leaching of carbonates occurs from pedogenesis during humid climatic phases, and that this is probably the primary mechanism of carbonate depletion of eolian sands in this area. Recent trends in sand dune activity from historic aerial photography and early explorers' accounts indicate that the few active dunes that presently exist have stabilized at a rate of 10-20% per decade, despite several severe droughts in the 20th century. This may be attributed to pre-settlement droughts that were more severe than those in historic times although regional dune stabilization may also be related, in part, to the spread of forest cover in the past few hundred years. Crown copyright (C) 2000 Published by Elsevier Science Ltd. All rights reserved.

33 CFR 165.927 - Safety Zone; St. Louis River, Duluth/Interlake Tar Remediation Site, Duluth, MN.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 33 Navigation and Navigable Waters 2 2010-07-01 2010-07-01 false Safety Zone; St. Louis River, Duluth/Interlake Tar Remediation Site, Duluth, MN. 165.927 Section 165.927 Navigation and Navigable... Coast Guard District § 165.927 Safety Zone; St. Louis River, Duluth/Interlake Tar Remediation Site...

Model of modern dynamic deposition in the east China Sea

NASA Astrophysics Data System (ADS)

Zhou, Fugen

1989-09-01

Since the last rising of sea level, two branches of the Kuroshio, the Huanghai (Yellow Sea) coastal current (HCC; mainly cold water mass) and the Changjiang River outflow have controlled the modern dynamic deposition in the East China Sea. There are three depositing areas on the sea-bed under the above currents: a relict sand area un der the Taiwan Warm Current and the Huanghai Warm Current at the south-eastern area, the about 60 km2 round mud bank under the Huanghai Coastal Current at the northern area and the large subaqueous delta of mainly fine sand and silt under the Changjiang discharge flow in its estuary and the large narrow mud bank under the Zhejiang-Fujian Coastal Current, another round mud bank under the Changjiang discharge flow off Hangzhou Bay. The relict sand area has a coarsesand block under the Taiwan Warm Current bypassing Taiwan at the northern part of the island. The two round mud banks were formed in relatively static states by an anticlockwise converging cyclonic eddy. The coarsesand block was formed by a clockwise diverging cyclonic eddy. This new dynamic deposition theory can be used to explain not only the dynamic deposition process of clay, but also the patchy distribution of sediments on the shelves of the world ocean s.

PAH volatilization following application of coal-tar-based pavement sealant

USGS Publications Warehouse

Van Metre, Peter C.; Majewski, Michael S.; Mahler, Barbara J.; Foreman, William T.; Braun, Christopher L.; Wilson, Jennifer T.; Burbank, Teresa L.

2012-01-01

Coal-tar-based pavement sealants, a major source of PAHs to urban water bodies, have recently been identified as a source of volatile PAHs to the atmosphere. We tracked the volatilization of PAHs for 1 year after application of a coal-tar-based pavement sealant by measuring gas-phase PAH concentrations above the pavement surface and solid-phase PAH concentrations in sealant scraped from the surface. Gas-phase concentrations at two heights (0.03 and 1.28 m) and wind speed were used to estimate volatilization flux. The sum of the concentrations of eight frequently detected PAHs (ΣPAH8) in the 0.03-m sample 1.6 h after application (297,000 ng m-3) was about 5000 times greater than that previously reported for the same height above unsealed parking lots (66 ng m-3). Flux at 1.6 h after application was estimated at 45,000 μg m-2 h-1 and decreased rapidly during the 45 days after application to 160 μg m-2 h-1. Loss of PAHs from the adhered sealant also was rapid, with about a 50% decrease in solid-phase ΣPAH8 concentration over the 45 days after application. There was general agreement, given the uncertainties, in the estimated mass of ΣPAH8 lost to the atmosphere on the basis of air sampling (2–3 g m-2) and adhered sealant sampling (6 g m-2) during the first 16 days after application, translating to a loss to the atmosphere of one-quarter to one-half of the PAHs in the sealcoat product. Combining the estimated mass of ΣPAH8 released to the atmosphere with a national-use estimate of coal-tar-based sealant suggests that PAH emissions from new coal-tar-based sealcoat applications each year (~1000 Mg) are larger than annual vehicle emissions of PAHs for the United States.

Experimental tsunami deposits: Linking hydrodynamics to sediment entrainment, advection lengths and downstream fining

NASA Astrophysics Data System (ADS)

Johnson, Joel P. L.; Delbecq, Katie; Kim, Wonsuck; Mohrig, David

2016-01-01

A goal of paleotsunami research is to quantitatively reconstruct wave hydraulics from sediment deposits in order to better understand coastal hazards. Simple models have been proposed to predict wave heights and velocities, based largely on deposit grain size distributions (GSDs). Although seemingly consistent with some recent tsunamis, little independent data exist to test these equations. We conducted laboratory experiments to evaluate inversion assumptions and uncertainties. A computer-controlled lift gate instantaneously released 6.5 m3 of water into a 32 m flume with shallow ponded water, creating a hydraulic bore that transported sand from an upstream source dune. Differences in initial GSDs and ponded water depths influenced entrainment, transport, and deposition. While the source dune sand was fully suspendable based on size alone, experimental tsunamis produced deposits dominated by bed load sand transport in the upstream 1/3 of the flume and suspension-dominated transport downstream. The suspension deposits exhibited downstream fining and thinning. At 95% confidence, a published advection-settling model predicts time-averaged flow depths to approximately a factor of two, and time-averaged downstream flow velocities to within a factor of 1.5. Finally, reasonable scaling is found between flume and field cases by comparing flow depths, inundation distances, Froude numbers, Rouse numbers and grain size trends in suspension-dominated tsunami deposits, justifying laboratory study of sediment transport and deposition by tsunamis.

Holocene reworking of a sand sheet in the Merrimack Embayment, Western Gulf of Maine

USGS Publications Warehouse

Hein, C.J.; FitzGerald, D.M.; Barnhardt, W.

2007-01-01

Recent bathymetric, backscatter, and seafloor sediment samples demonstrate that a large sand sheet was formed in the inner shelf by the reworking of the Merrimack River lowstand delta (deposited 12 kya; currently at 45 m depth) and braid plain during the Holocene transgression. Asymmetric bedforms and distinct grain size distributions suggest the sand sheet is actively being reworked by inner-shelf processes. Bottom sediments range from silty sand at the submerged delta to coarse sand and fine gravel in the innermost shelf (depth: 10-50 m). Coarse-grained sand comprises an expansive (32 km2 ) featureless sand sheet centered off the Merrimack River. Fine-grained sand discontinuously overlies this sand sheet in many locations and forms long wavelength (100 – 800 m), low amplitude (1-2 m), asymmetrical bedforms. Sets of these bedforms are oriented from slightly oblique offshore to onshore; several bedform sets are located within 1 km and oriented orthogonally to one another. Along the paleo-delta front north-northwest oriented bedforms are dominant. Inshore of these features, the bedforms become more closely spaced and have orientations to the west and westsouthwest. Preliminary data suggest that the combined forcings of instantaneous storm-wave generated shear stress and storm-induced currents associated with high energy northeast storm events may be responsible for sand sheet reworking and bedform development.

Developing technologies for synthetic fuels

NASA Astrophysics Data System (ADS)

Sprow, F. B.

1981-05-01

After consideration of a likely timetable for the development of a synthetic fuels industry and its necessary supporting technology, the large variety of such fuels and their potential roles is assessed along with their commercialization outlook. Among the fuel production methods considered are: (1) above-ground retorting of oil shale; (2) in-situ shale retorting; (3) open pit mining of tar sands; (4) in-situ steam stimulation of tar sands; (5) coal gasification; (6) methanol synthesis from carbon monoxide and hydrogen; and (7) direct coal liquefaction by the hydrogenation of coal. It is shown that while the U.S. has very limited resource bases for tar sands and heavy crudes, the abundance of shale in the western states and the abundance and greater geographical dispersion of coal will make these the two most important resources of a future synthetic fuels industry.

Welded slump-graded sand couplets: evidence for slide generated turbidity currents

NASA Astrophysics Data System (ADS)

Stanley, Daniel Jean

1982-09-01

Some massive channelized strata preserved in the rock record are characterized by a lower slump member which evolves upward to a turbidite. This merging is indicative of probable generation of sediment gravity flows from submarine sliding. Conditions essential for deposition of such sequences are short transport distance between point of failure and depositional site, and an environment likely to retain both facies. Fan valleys are a likely setting for welded couplets: flowing sand, initiated by the sliding event, comes to rest at nearly the same time and position as the slump mass deposited near the base of the valley wall and in the axis proper.

Impact of Genetic Variations in HIV-1 Tat on LTR-Mediated Transcription via TAR RNA Interaction.

PubMed

Ronsard, Larance; Ganguli, Nilanjana; Singh, Vivek K; Mohankumar, Kumaravel; Rai, Tripti; Sridharan, Subhashree; Pajaniradje, Sankar; Kumar, Binod; Rai, Devesh; Chaudhuri, Suhnrita; Coumar, Mohane S; Ramachandran, Vishnampettai G; Banerjea, Akhil C

2017-01-01

HIV-1 evades host defense through mutations and recombination events, generating numerous variants in an infected patient. These variants with an undiminished virulence can multiply rapidly in order to progress to AIDS. One of the targets to intervene in HIV-1 replication is the trans -activator of transcription (Tat), a major regulatory protein that transactivates the long terminal repeat promoter through its interaction with trans -activation response (TAR) RNA. In this study, HIV-1 infected patients ( n = 120) from North India revealed Ser46Phe (20%) and Ser61Arg (2%) mutations in the Tat variants with a strong interaction toward TAR leading to enhanced transactivation activities. Molecular dynamics simulation data verified that the variants with this mutation had a higher binding affinity for TAR than both the wild-type Tat and other variants that lacked Ser46Phe and Ser61Arg. Other mutations in Tat conferred varying affinities for TAR interaction leading to differential transactivation abilities. This is the first report from North India with a clinical validation of CD4 counts to demonstrate the influence of Tat genetic variations affecting the stability of Tat and its interaction with TAR. This study highlights the co-evolution pattern of Tat and predominant nucleotides for Tat activity, facilitating the identification of genetic determinants for the attenuation of viral gene expression.

Generation and migration of Bitumen and oil from the oil shale interval of the Eocene Green River formation, Uinta Basin, Utah

USGS Publications Warehouse

Johnson, Ronald C.; Birdwell, Justin E.; Mercier, Tracey J.

2016-01-01

The results from the recent U.S. Geological Survey assessment of in-place oil shale resources of the Eocene Green River Formation, based primarily on the Fischer assay method, are applied herein to define areas where the oil shale interval is depleted of some of its petroleum-generating potential along the deep structural trough of the basin and to make: (1) a general estimates of the amount of this depletion, and (2) estimate the total volume of petroleum generated. Oil yields (gallons of oil per ton of rock, GPT) and in-place oil (barrels of oil per acre, BPA) decrease toward the structural trough of the basin, which represents an offshore lacustrine area that is believed to have originally contained greater petroleum-generating potential than is currently indicated by measured Fischer assay oil yields. Although this interval is considered to be largely immature for oil generation based on vitrinite reflectance measurements, the oil shale interval is a likely source for the gilsonite deposits and much of the tar sands in the basin. Early expulsion of petroleum may have occurred due to the very high organic carbon content and oil-prone nature of the Type I kerogen present in Green River oil shale. In order to examine the possible sources and migration pathways for the tar sands and gilsonite deposits, we have created paleogeographic reconstructions of several oil shale zones in the basin as part of this study.

Dark grains of sand: a geological storytelling

NASA Astrophysics Data System (ADS)

Gallo Maresca, Magda

2017-04-01

In the secondary Italian school the Earth science learning begins at first year, in synergy with other natural science subjects such as Astronomy, Chemistry and Biology. Italian teachers have to focus on the landscape geomorphological aspects and often Earth processes are difficult to display since they are related to certain phenomena happened during the past and often far from the involved country. In order to better understand the environment surrounding us, very simple and poor materials, like sands, allow the teachers to create attractive lab experiences. According to the IBSE (Inquiry Based Science Education) approach, a learning unit has been implemented starting from a walking along the light carbonate beaches of the Adriatic sea: a smart look to the sands ("engage step"), stroke the students fantasy pushing them to explore some strange black grains on the sands. Dirty sands? Or rock landscape, soil degradation and Ofanto river and coastal processes (erosion, transportation and deposition)? This was the teaching challenge. Due to the youngest age, a third level, guided inquiry, was adopted so the teacher is the "guide of inquiry" encouraging the students using the research question ("Why is the sand dark?", "Do all sands look the same?", "Where does it come from?") and driving the students around their investigation plans ("How can I measure grain size?"). A procedure to answer the above questions and validate the results and explanations has been implemented to allow the students to be proactive in their study. During the learning activities will be the students to ask for field trip to elaborate their new knowledge, verify and visualize the speculated processes. The teaching skills allow to address several geosciences domains such as mineralogy, petrology, regional geology and geodynamics as well as other scientific disciplines such as mathematics (more specifically statistics), forensic science and even life sciences (the presence of bioclasts might

Marketing 'less harmful, low-tar' cigarettes is a key strategy of the industry to counter tobacco control in China.

PubMed

Yang, Gonghuan

2014-03-01

While the 'low-tar' scheme has been widely recognised as a misleading tactic used by the tobacco industry to deceive the public about the true risks of cigarette smoking, a similar campaign using the slogan of 'less harmful, low tar' was launched by the Chinese tobacco industry, that is, State Tobacco Monopoly Administration/China National Tobacco Corporation and began to gain traction during the last decade. Despite the fact that no sufficient research evidence supports the claims made by the industry that these cigarettes are safer, the Chinese tobacco industry has continued to promote them using various health claims. As a result, the production and sales of 'less harmful, low-tar' cigarettes have increased dramatically since 2000. Recently, a tobacco industry senior researcher, whose main research area is 'less harmful, low-tar' cigarettes, was elected as an Academician to the prestigious Chinese Academy of Engineering for his contribution to developing 'less harmful, low-tar' cigarettes. The tobacco researcher's election caused an outcry from the tobacco control community and the general public in China. This paper discusses the Chinese tobacco industry's 'less harmful, low-tar' initiatives and calls for the Chinese government to stop the execution of this deceptive strategy for tobacco marketing.

Relationship between cigarette format and mouth-level exposure to tar and nicotine in smokers of Russian king-size cigarettes.

PubMed

Ashley, Madeleine; Dixon, Mike; Prasad, Krishna

2014-10-01

Differences in length and circumference of cigarettes may influence smoker behaviour and exposure to smoke constituents. Superslim king-size (KSSS) cigarettes (17mm circumference versus 25mm circumference of conventional king-size [KS] cigarettes), have gained popularity in several countries, including Russia. Some smoke constituents are lower in machine-smoked KSSS versus KS cigarettes, but few data exist on actual exposure in smokers. We investigated mouth-level exposure (MLE) to tar and nicotine in Russian smokers of KSSS versus KS cigarettes and measured smoke constituents under machine-smoking conditions. MLE to tar was similar for smokers of 1mg ISO tar yield products, but lower for smokers of 4mg and 7mg KSSS versus KS cigarettes. MLE to nicotine was lower in smokers of 4mg KSSS versus KS cigarettes, but not for other tar bands. No gender differences were observed for nicotine or tar MLE. Under International Organization for Standardization, Health Canada Intense and Massachusetts regimes, KSSS cigarettes tended to yield less carbon monoxide, acetaldehyde, nitric oxide, acrylonitrile, benzene, 1,3-butadiene and tobacco-specific nitrosamines, but more formaldehyde, than KS cigarettes. In summary, differences in MLE were observed between cigarette formats, but not systematically across pack tar bands. Copyright © 2014 The Authors. Published by Elsevier Inc. All rights reserved.

A NEW MODEL OF PODIAL DEPOSIT FEEDING IN THE SAND DOLLAR, MELLITA QUINQUJESPERFORATA (LESKE): THE SIEVE HYPOTHESIS CHALLENGED.