Science.gov

Sample records for 4h shell mounds

  1. Contaminant exposures at the 4H shell mounds in the Santa Barbara Channel.

    PubMed

    Phillips, Charles R; Salazar, Michael H; Salazar, Sandra M; Snyder, Barry J

    2006-12-01

    Remobilization, bioavailability, and potential toxicity of chemical contaminants were evaluated at the 4H shell mounds - the site of abandoned offshore oil and gas production platforms in the Santa Barbara Channel region of the Southern California Bight. Evaluations used a weight-of-evidence approach based on results from bulk phase chemical analyses and laboratory toxicity testing of shell mound cores, in situ field bioassays using caged mussels, and surficial sediment chemistry. Shell mound cores contained elevated concentrations of metals associated with drilling wastes (e.g., Ba, Cr, Pb, and Zn), as well as monocyclic and polycyclic aromatic hydrocarbons (PAHs). The highest concentrations along with pockets of free oil were associated with the middle "cuttings" stratum. Sediments composited from all core strata caused significant acute toxicity and bioaccumulation of Ba and PAHs in test organisms during laboratory exposures. In contrast, caged mussels placed at each of the shell mounds for a period of 57-58 days had greater than 90% survival, and there were no significant differences in survival of mussels placed at the shell mounds and corresponding reference sites. While all mussel samples exhibited increases in shell length, whole animal weight, and tissue lipid content, in some cases growth metrics for the shell mound mussels were significantly higher than those for the reference sites. Concentrations of metals, PAHs, and polychlorinated biphenyls (PCBs) in tissues of the shell mound mussels were not significantly different from those at reference sites. The presence of labile aromatic hydrocarbons in shell mound cores and absence of significant contaminant accumulation of tissues of caged mussels indicated that chemical contaminants are not being remobilized from the 4H shell mounds. Surficial bottom sediments near the shell mounds contained elevated Ba concentrations that probably were associated with drilling wastes. However, concentrations did not

  2. Contaminant exposures at the 4H shell mounds in the Santa Barbara Channel.

    PubMed

    Phillips, Charles R; Salazar, Michael H; Salazar, Sandra M; Snyder, Barry J

    2006-12-01

    Remobilization, bioavailability, and potential toxicity of chemical contaminants were evaluated at the 4H shell mounds - the site of abandoned offshore oil and gas production platforms in the Santa Barbara Channel region of the Southern California Bight. Evaluations used a weight-of-evidence approach based on results from bulk phase chemical analyses and laboratory toxicity testing of shell mound cores, in situ field bioassays using caged mussels, and surficial sediment chemistry. Shell mound cores contained elevated concentrations of metals associated with drilling wastes (e.g., Ba, Cr, Pb, and Zn), as well as monocyclic and polycyclic aromatic hydrocarbons (PAHs). The highest concentrations along with pockets of free oil were associated with the middle "cuttings" stratum. Sediments composited from all core strata caused significant acute toxicity and bioaccumulation of Ba and PAHs in test organisms during laboratory exposures. In contrast, caged mussels placed at each of the shell mounds for a period of 57-58 days had greater than 90% survival, and there were no significant differences in survival of mussels placed at the shell mounds and corresponding reference sites. While all mussel samples exhibited increases in shell length, whole animal weight, and tissue lipid content, in some cases growth metrics for the shell mound mussels were significantly higher than those for the reference sites. Concentrations of metals, PAHs, and polychlorinated biphenyls (PCBs) in tissues of the shell mound mussels were not significantly different from those at reference sites. The presence of labile aromatic hydrocarbons in shell mound cores and absence of significant contaminant accumulation of tissues of caged mussels indicated that chemical contaminants are not being remobilized from the 4H shell mounds. Surficial bottom sediments near the shell mounds contained elevated Ba concentrations that probably were associated with drilling wastes. However, concentrations did not

  3. From Shell Midden to Midden-Mound: The Geoarchaeology of Mound Key, an Anthropogenic Island in Southwest Florida, USA.

    PubMed

    Thompson, Victor D; Marquardt, William H; Cherkinsky, Alexander; Roberts Thompson, Amanda D; Walker, Karen J; Newsom, Lee A; Savarese, Michael

    2016-01-01

    Mound Key was once the capital of the Calusa Kingdom, a large Pre-Hispanic polity that controlled much of southern Florida. Mound Key, like other archaeological sites along the southwest Gulf Coast, is a large expanse of shell and other anthropogenic sediments. The challenges that these sites pose are largely due to the size and areal extent of the deposits, some of which begin up to a meter below and exceed nine meters above modern sea levels. Additionally, the complex depositional sequences at these sites present difficulties in determining their chronology. Here, we examine the development of Mound Key as an anthropogenic island through systematic coring of the deposits, excavations, and intensive radiocarbon dating. The resulting data, which include the reversals of radiocarbon dates from cores and dates from mound-top features, lend insight into the temporality of site formation. We use these insights to discuss the nature and scale of human activities that worked to form this large island in the context of its dynamic, environmental setting. We present the case that deposits within Mound Key's central area accumulated through complex processes that represent a diversity of human action including midden accumulation and the redeposition of older sediments as mound fill.

  4. From Shell Midden to Midden-Mound: The Geoarchaeology of Mound Key, an Anthropogenic Island in Southwest Florida, USA

    PubMed Central

    Cherkinsky, Alexander; Roberts Thompson, Amanda D.; Walker, Karen J.; Newsom, Lee A.; Savarese, Michael

    2016-01-01

    Mound Key was once the capital of the Calusa Kingdom, a large Pre-Hispanic polity that controlled much of southern Florida. Mound Key, like other archaeological sites along the southwest Gulf Coast, is a large expanse of shell and other anthropogenic sediments. The challenges that these sites pose are largely due to the size and areal extent of the deposits, some of which begin up to a meter below and exceed nine meters above modern sea levels. Additionally, the complex depositional sequences at these sites present difficulties in determining their chronology. Here, we examine the development of Mound Key as an anthropogenic island through systematic coring of the deposits, excavations, and intensive radiocarbon dating. The resulting data, which include the reversals of radiocarbon dates from cores and dates from mound-top features, lend insight into the temporality of site formation. We use these insights to discuss the nature and scale of human activities that worked to form this large island in the context of its dynamic, environmental setting. We present the case that deposits within Mound Key’s central area accumulated through complex processes that represent a diversity of human action including midden accumulation and the redeposition of older sediments as mound fill. PMID:27123928

  5. Synthesis of 4H/fcc-Au@Metal Sulfide Core-Shell Nanoribbons.

    PubMed

    Fan, Zhanxi; Zhang, Xiao; Yang, Jian; Wu, Xue-Jun; Liu, Zhengdong; Huang, Wei; Zhang, Hua

    2015-09-01

    Although great advances on the synthesis of Au-semiconductor heteronanostructures have been achieved, the crystal structure of Au components is limited to the common face-centered cubic (fcc) phase. Herein, we report the synthesis of 4H/fcc-Au@Ag2S core-shell nanoribbon (NRB) heterostructures from the 4H/fcc Au@Ag NRBs via the sulfurization of Ag. Remarkably, the obtained 4H/fcc-Au@Ag2S NRBs can be further converted to a novel class of 4H/fcc-Au@metal sulfide core-shell NRB heterostructures, referred to as 4H/fcc-Au@MS (M = Cd, Pb or Zn), through the cation exchange. We believe that these novel 4H/fcc-Au@metal sulfide NRB heteronanostructures may show some promising applications in catalysis, surface enhanced Raman scattering, solar cells, photothermal therapy, etc.

  6. Lutz's spontaneous sedimentation technique and the paleoparasitological analysis of sambaqui (shell mound) sediments

    PubMed Central

    Camacho, Morgana; Pessanha, Thaíla; Leles, Daniela; Dutra, Juliana MF; Silva, Rosângela; de Souza, Sheila Mendonça; Araujo, Adauto

    2013-01-01

    Parasite findings in sambaquis (shell mounds) are scarce. Although the 121 shell mound samples were previously analysed in our laboratory, we only recently obtained the first positive results. In the sambaqui of Guapi, Rio de Janeiro, Brazil, paleoparasitological analysis was performed on sediment samples collected from various archaeological layers, including the superficial layer as a control. Eggs of Acanthocephala, Ascaridoidea and Heterakoidea were found in the archaeological layers. We applied various techniques and concluded that Lutz's spontaneous sedimentation technique is effective for concentrating parasite eggs in sambaqui soil for microscopic analysis. PMID:23579793

  7. Electron spin resonance dating of human bones from Brazilian shell-mounds (Sambaquís).

    PubMed

    Mascarenhas, S; Baffa Filho, O; Ikeya, M

    1982-12-01

    Electron spin resonance (ESR) signals from bone increase with exposure to radiation. This permits the dating of ancient bone from its exposure to natural radiation over the centuries. The ESR technique was used for dating human bones from Brazilian shell mounds. The results were compared with 14C dates on charcoal found near the bone. The natural radiation dose rate of the bones was about 0.01 Gy/year (1 rad/year), similar to that found in Japanese shell-mounds. Ages of the bone samples dated ranged from 2000-5000 years BP.

  8. Geoarchaeological approaches to understanding human-environment interactions in Australia's tropical north: the Weipa shell mounds revisited.

    NASA Astrophysics Data System (ADS)

    Fanning, P. C.; Holdaway, S. J.; Shiner, J.; Petchey, F.

    2012-04-01

    Western Cape York Peninsula, particularly the Weipa region, has seen sustained archaeological investigation since the 1960s. These studies primarily concentrated on the shell mounds associated with coastal environments first observed at the beginning of the 20th century. Despite claims that the shell mounds were of natural origin, archaeological investigations convincingly demonstrated that they are primarily cultural deposits. Geomorphological studies indicate that chenier (beach ridge) formation occurred after sea-level stabilisation in the mid- to late Holocene, and is connected to the formation of estuaries at the mouths of the Mission, Pine, Hey and Embley Rivers. Anadara shell bed formation is in turn connected with the evolution of the estuaries. However, the relationship between shell mound age and location relative to the coastline at Weipa is neither well defined, nor tested at multiple locations. Given that the coast is susceptible to the effects of sea-level fluctuations and environmental change, and the Anadara beds can become depleted as a result of environmental shifts, the shell mounds provide a datable record of human reaction to coastal landscape and environmental change. Here, we report preliminary results of a new investigation of the shell mounds of the Weipa region. Radiocarbon and OSL-based age determinations from samples of shell, charcoal and sediment collected from trenches excavated into shell mounds on the northern shore of the Embley River indicate a relationship between the time of initial accumulation of shell and the age of the landform features upon which they were built, which in turn are a result of coastline evolution during the mid to late Holocene. These mounds are the oldest yet recorded for the Weipa region, with accumulation in one case commencing around 3500 cal BP. Accumulation appears to be more or less continuous, and abruptly ceases after 400-650 yrs. We discuss implications for understanding human

  9. Amino acid racemization dating of marine shells: A mound of possibilities

    PubMed Central

    Demarchi, Beatrice; Williams, Matt G.; Milner, Nicky; Russell, Nicola; Bailey, Geoff; Penkman, Kirsty

    2011-01-01

    Shell middens are one of the most important and widespread indicators for human exploitation of marine resources and occupation of coastal environments. Establishing an accurate and reliable chronology for these deposits has fundamental implications for understanding the patterns of human evolution and dispersal. This paper explores the potential application of a new methodology of amino acid racemization (AAR) dating of shell middens and describes a simple protocol to test the suitability of different molluscan species. This protocol provides a preliminary test for the presence of an intracrystalline fraction of proteins (by bleaching experiments and subsequent heating at high temperature), checking the closed system behaviour of this fraction during diagenesis. Only species which pass both tests can be considered suitable for further studies to obtain reliable age information. This amino acid geochronological technique is also applied to midden deposits at two latitudinal extremes: Northern Scotland and the Southern Red Sea. Results obtained in this study indicate that the application of this new method of AAR dating of shells has the potential to aid the geochronological investigation of shell mounds in different areas of the world. PMID:21776187

  10. Synthesis of 4H/fcc-Au@M (M = Ir, Os, IrOs) Core-Shell Nanoribbons For Electrocatalytic Oxygen Evolution Reaction.

    PubMed

    Fan, Zhanxi; Luo, Zhimin; Chen, Ye; Wang, Jie; Li, Bing; Zong, Yun; Zhang, Hua

    2016-08-01

    The high-yield synthesis of 4H/face-centered cubic (fcc)-Au@Ir core-shell nanoribbons (NRBs) is achieved via the direct growth of Ir on 4H Au NRBs under ambient conditions. Importantly, this method can be used to synthesize 4H/fcc-Au@Os and 4H/fcc-Au@IrOs core-shell NRBs. Significantly, the obtained 4H/fcc-Au@Ir core-shell NRBs demonstrate an exceptional electrocatalytic activity toward the oxygen evolution reaction under acidic condition, which is much higher than that of the commercial Ir/C catalyst.

  11. Impacts from Partial Removal of Decommissioned Oil and Gas Platforms on Fish Biomass and Production on the Remaining Platform Structure and Surrounding Shell Mounds.

    PubMed

    Claisse, Jeremy T; Pondella, Daniel J; Love, Milton; Zahn, Laurel A; Williams, Chelsea M; Bull, Ann S

    2015-01-01

    When oil and gas platforms become obsolete they go through a decommissioning process. This may include partial removal (from the surface to 26 m depth) or complete removal of the platform structure. While complete removal would likely eliminate most of the existing fish biomass and associated secondary production, we find that the potential impacts of partial removal would likely be limited on all but one platform off the coast of California. On average 80% of fish biomass and 86% of secondary fish production would be retained after partial removal, with above 90% retention expected for both metrics on many platforms. Partial removal would likely result in the loss of fish biomass and production for species typically found residing in the shallow portions of the platform structure. However, these fishes generally represent a small proportion of the fishes associated with these platforms. More characteristic of platform fauna are the primarily deeper-dwelling rockfishes (genus Sebastes). "Shell mounds" are biogenic reefs that surround some of these platforms resulting from an accumulation of mollusk shells that have fallen from the shallow areas of the platforms mostly above the depth of partial removal. We found that shell mounds are moderately productive fish habitats, similar to or greater than natural rocky reefs in the region at comparable depths. The complexity and areal extent of these biogenic habitats, and the associated fish biomass and production, will likely be reduced after either partial or complete platform removal. Habitat augmentation by placing the partially removed platform superstructure or some other additional habitat enrichment material (e.g., rock boulders) on the seafloor adjacent to the base of partially removed platforms provides additional options to enhance fish production, potentially mitigating reductions in shell mound habitat.

  12. Impacts from Partial Removal of Decommissioned Oil and Gas Platforms on Fish Biomass and Production on the Remaining Platform Structure and Surrounding Shell Mounds.

    PubMed

    Claisse, Jeremy T; Pondella, Daniel J; Love, Milton; Zahn, Laurel A; Williams, Chelsea M; Bull, Ann S

    2015-01-01

    When oil and gas platforms become obsolete they go through a decommissioning process. This may include partial removal (from the surface to 26 m depth) or complete removal of the platform structure. While complete removal would likely eliminate most of the existing fish biomass and associated secondary production, we find that the potential impacts of partial removal would likely be limited on all but one platform off the coast of California. On average 80% of fish biomass and 86% of secondary fish production would be retained after partial removal, with above 90% retention expected for both metrics on many platforms. Partial removal would likely result in the loss of fish biomass and production for species typically found residing in the shallow portions of the platform structure. However, these fishes generally represent a small proportion of the fishes associated with these platforms. More characteristic of platform fauna are the primarily deeper-dwelling rockfishes (genus Sebastes). "Shell mounds" are biogenic reefs that surround some of these platforms resulting from an accumulation of mollusk shells that have fallen from the shallow areas of the platforms mostly above the depth of partial removal. We found that shell mounds are moderately productive fish habitats, similar to or greater than natural rocky reefs in the region at comparable depths. The complexity and areal extent of these biogenic habitats, and the associated fish biomass and production, will likely be reduced after either partial or complete platform removal. Habitat augmentation by placing the partially removed platform superstructure or some other additional habitat enrichment material (e.g., rock boulders) on the seafloor adjacent to the base of partially removed platforms provides additional options to enhance fish production, potentially mitigating reductions in shell mound habitat. PMID:26332384

  13. Impacts from Partial Removal of Decommissioned Oil and Gas Platforms on Fish Biomass and Production on the Remaining Platform Structure and Surrounding Shell Mounds

    PubMed Central

    Claisse, Jeremy T.; Pondella, Daniel J.; Love, Milton; Zahn, Laurel A.; Williams, Chelsea M.; Bull, Ann S.

    2015-01-01

    When oil and gas platforms become obsolete they go through a decommissioning process. This may include partial removal (from the surface to 26 m depth) or complete removal of the platform structure. While complete removal would likely eliminate most of the existing fish biomass and associated secondary production, we find that the potential impacts of partial removal would likely be limited on all but one platform off the coast of California. On average 80% of fish biomass and 86% of secondary fish production would be retained after partial removal, with above 90% retention expected for both metrics on many platforms. Partial removal would likely result in the loss of fish biomass and production for species typically found residing in the shallow portions of the platform structure. However, these fishes generally represent a small proportion of the fishes associated with these platforms. More characteristic of platform fauna are the primarily deeper-dwelling rockfishes (genus Sebastes). “Shell mounds” are biogenic reefs that surround some of these platforms resulting from an accumulation of mollusk shells that have fallen from the shallow areas of the platforms mostly above the depth of partial removal. We found that shell mounds are moderately productive fish habitats, similar to or greater than natural rocky reefs in the region at comparable depths. The complexity and areal extent of these biogenic habitats, and the associated fish biomass and production, will likely be reduced after either partial or complete platform removal. Habitat augmentation by placing the partially removed platform superstructure or some other additional habitat enrichment material (e.g., rock boulders) on the seafloor adjacent to the base of partially removed platforms provides additional options to enhance fish production, potentially mitigating reductions in shell mound habitat. PMID:26332384

  14. 4-H and Iowa.

    ERIC Educational Resources Information Center

    Gore, Deborah, Ed.

    1988-01-01

    This issue focuses on Iowa's role in the historical development of the 4-H youth program. "Roots in Iowa" and "Jessie Field Shambaugh: The Mother of 4-H" (J. Friedel) describes the rural Iowan roots of the 4-H program, which today is located in 80 different countries, and give the story of its founder. Jessie Shambaugh, a rural Iowa teacher and…

  15. Stair-stepped Mound

    NASA Technical Reports Server (NTRS)

    2003-01-01

    MGS MOC Release No. MOC2-429, 22 July 2003

    This April 2003 Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows a stair-stepped mound of sedimentary rock (right of center) on the floor of a large impact crater in western Arabia Terra near 11.0oN, 4.4oW. Sedimentary rock outcrops are common in the craters of this region. The repeated thickness and uniformity of the layers that make up this mound suggest that their depositional environment was one in which cyclic or episodic events occurred over some period of time. The sediments might have been deposited in a lake, or they may have settled directly out of the atmosphere. Most of the layered material was later eroded away, leaving this circular mound and the other nearby mesas and knobs. The image is illuminated by sunlight from the lower left.

  16. Managing 4-H Volunteer Staff: A 4-H Intern Report.

    ERIC Educational Resources Information Center

    Martin, Hope M.

    The 4-H intern report organizes concepts and materials to aid the extension worker in his role as coordinator and trainer of 4-H volunteer staff. A 10-item task analysis of the extension worker--4-H and youth--as volunteer leader coordinator is presented. The importance of managing a volunteer staff is touched upon, and models for job descriptions…

  17. Mound Supports Galileo

    SciTech Connect

    Monsanto Research Corporation

    1986-01-01

    This video describes the invention of Radioisotope Thermoelectric Generators (RTGs) at Mound Laboratory, and radioisotope heat source production from 1 watt-thermal to 2400 watts-thermal. RTGs have been used in many space vehicles, but the RTG built for the Galileo mission to orbit Jupiter is the largest. This RTG unit will produce 4400 watts-thermal and convert to 300 watts-electric. The plutonium-238 heat source assembly and test at Mound is described. The RTGs are tested under simulated mission conditions. The RTG leakage radiation is carefully measured for background compensation for on-board radiation monitoring instruments.

  18. Keeping 4-H Volunteer Leaders.

    ERIC Educational Resources Information Center

    Smith, Keith L.; Bigler, Nancy M.

    1985-01-01

    This study showed that continuing and discontinuing volunteer 4-H Club leaders are significantly different in their geographical location, number of children in family, and number of children in family who have participated in 4-H. These variables may affect the volunteer's decision to continue serving as a 4-H Club leader. (Author/CT)

  19. Mound publications for 1991

    SciTech Connect

    Nowka, Stephen L.

    1992-05-01

    This document is a compilation of all Mound formal technical publications and oral presentations for calendar year 1991. It is intended to serve as an aid to personnel in obtaining or referring to specific publications by giving the proper complete reference for each information item published during the year. Some items, such as proceedings publications, may have issue dates or periods of coverage prior to 1991; however, they were formally published during 1991.

  20. Mound facility physical characterization

    SciTech Connect

    Tonne, W.R.; Alexander, B.M.; Cage, M.R.; Hase, E.H.; Schmidt, M.J.; Schneider, J.E.; Slusher, W.; Todd, J.E.

    1993-12-01

    The purpose of this report is to provide a baseline physical characterization of Mound`s facilities as of September 1993. The baseline characterizations are to be used in the development of long-term future use strategy development for the Mound site. This document describes the current missions and alternative future use scenarios for each building. Current mission descriptions cover facility capabilities, physical resources required to support operations, current safety envelope and current status of facilities. Future use scenarios identify potential alternative future uses, facility modifications required for likely use, facility modifications of other uses, changes to safety envelope for the likely use, cleanup criteria for each future use scenario, and disposition of surplus equipment. This Introductory Chapter includes an Executive Summary that contains narrative on the Functional Unit Material Condition, Current Facility Status, Listing of Buildings, Space Plans, Summary of Maintenance Program and Repair Backlog, Environmental Restoration, and Decontamination and Decommissioning Programs. Under Section B, Site Description, is a brief listing of the Site PS Development, as well as Current Utility Sources. Section C contains Site Assumptions. A Maintenance Program Overview, as well as Current Deficiencies, is contained within the Maintenance Program Chapter.

  1. Geoprospection of Mound A, Etowah Mounds State Park, Georgia

    NASA Astrophysics Data System (ADS)

    Reppert, P. M.; Schneider, K. A.; Garrison, E. G.

    2005-05-01

    Mound A, located at Etowah Mounds State Park, Georgia, was the subject of a multi-sensor geoprospection study in 2001-02. Mound A, a late prehistoric mound, built by the Mississippian Culture, ca. 1250 - 1400 AD,is, due to its size, ~ 1 ha in area at the base and 20 m in height, a formidable subject for the use of shallow geoprospection techniques. Techniques used were ground radar (GPR), conductivity (EM) and electrical (resistivity) methods. Common Mid-Point (CMP) radar data produced detail on the mound interior from surface to base. Electrical pesudo-sections produced excellent detail of the mound's interior. The EM data appears relevant for only the upper half of the mound, perhaps to a depth of 10 m, and suggests significant heterogeneity in the sediment fill used in the mound's construction. Our results speak directly to the efficacy of shallow geophyscial techniques in exploring large archeological mounds and tells. Another important aspect of this study is the use of a geoprospection approach as a non-invasice methodology for characterizing culturally sensitive archaeological sites.

  2. Thermochemistry of disputed soot formation intermediates C4H3 and C4H5.

    PubMed

    Wheeler, Steven E; Allen, Wesley D; Schaefer, Henry F

    2004-11-01

    Accurate isomeric energy differences and standard enthalpies of formation for disputed intermediates in soot formation, C(4)H(3) and C(4)H(5), have been determined through systematic extrapolations of ab initio energies. Electron correlation has been included through second-order Z-averaged perturbation theory (ZAPT2), and spin-restricted, open-shell coupled-cluster methods through triple excitations [ROCCSD, ROCCSD(T), and ROCCSDT] utilizing the correlation-consistent hierarchy of basis sets, cc-pVXZ (X = D, T, Q, 5, and 6), followed by extrapolations to the complete basis set limit via the focal point method of Allen and co-workers. Reference geometries were fully optimized at the ROCCSD(T) level with a TZ(2d1f,2p1d) basis set. Our analysis finds that the resonance-stabilized i-C(4)H(3) and i-C(4)H(5) isomers lie 11.8 and 10.7 kcal mol(-1) below E-n-C(4)H(3) and E-n-C(4)H(5), respectively, several kcal mol(-1) (more, less) than reported in recent (diffusion Monte Carlo, B3LYP density-functional) studies. Moreover, in these systems Gaussian-3 (G3) theory suffers from large spin contamination in electronic wave functions, poor reference geometries, and anomalous vibrational frequencies, but fortuitous cancellation of these sizable errors leads to isomerization energies apparently accurate to 1 kcal mol(-1). Using focal-point extrapolations for isodesmic reactions, we determine the enthalpies of formation (delta(f)H(0) (composite function)) for i-C(4)H(3), Z-n-C(4)H(3), E-n-C(4)H(3), i-C(4)H(5), Z-n-C(4)H(5), and E-n-C(4)H(5) to be 119.0, 130.8, 130.8, 78.4, 89.7, and 89.1 kcal mol(-1), respectively. These definitive values remove any remaining uncertainty surrounding the thermochemistry of these isomers in combustion models, allowing for better assessment of whether even-carbon pathways contribute to soot formation. PMID:15527344

  3. Thermochemistry of disputed soot formation intermediates C4H3 and C4H5

    NASA Astrophysics Data System (ADS)

    Wheeler, Steven E.; Allen, Wesley D.; Schaefer, Henry F.

    2004-11-01

    Accurate isomeric energy differences and standard enthalpies of formation for disputed intermediates in soot formation, C4H3 and C4H5, have been determined through systematic extrapolations of ab initio energies. Electron correlation has been included through second-order Z-averaged perturbation theory (ZAPT2), and spin-restricted, open-shell coupled-cluster methods through triple excitations [ROCCSD, ROCCSD(T), and ROCCSDT] utilizing the correlation-consistent hierarchy of basis sets, cc-pVXZ (X=D, T, Q, 5, and 6), followed by extrapolations to the complete basis set limit via the focal point method of Allen and co-workers. Reference geometries were fully optimized at the ROCCSD(T) level with a TZ(2d1f,2p1d) basis set. Our analysis finds that the resonance-stabilized i-C4H3 and i-C4H5 isomers lie 11.8 and 10.7 kcal mol-1 below E-n-C4H3 and E-n-C4H5, respectively, several kcal mol-1 (more, less) than reported in recent (diffusion Monte Carlo, B3LYP density-functional) studies. Moreover, in these systems Gaussian-3 (G3) theory suffers from large spin contamination in electronic wave functions, poor reference geometries, and anomalous vibrational frequencies, but fortuitous cancellation of these sizable errors leads to isomerization energies apparently accurate to 1 kcal mol-1. Using focal-point extrapolations for isodesmic reactions, we determine the enthalpies of formation (ΔfH0∘) for i-C4H3, Z-n-C4H3, E-n-C4H3, i-C4H5, Z-n-C4H5, and E-n-C4H5 to be 119.0, 130.8, 130.8, 78.4, 89.7, and 89.1 kcal mol-1, respectively. These definitive values remove any remaining uncertainty surrounding the thermochemistry of these isomers in combustion models, allowing for better assessment of whether even-carbon pathways contribute to soot formation.

  4. The Mud-Laden Mound.

    ERIC Educational Resources Information Center

    Sams, Larry M.

    1990-01-01

    A family's trip to Winterville Indian Mounds State Park in Mississippi is described, focusing on the frustrations of a gifted six-year old who fell in the muck of the Great Temple Mound, and on the joys of seeing spectacular displays of ancient earthworks. (JDD)

  5. Single Domain SmCo5@Co Exchange-coupled Magnets Prepared from Core/shell Sm[Co(CN)6]·4H2O@GO Particles: A Novel Chemical Approach

    PubMed Central

    Yang, Ce; Jia, Lihui; Wang, Shouguo; Gao, Chen; Shi, Dawei; Hou, Yanglong; Gao, Song

    2013-01-01

    SmCo5 based magnets with smaller size and larger maximum energy product have been long desired in various fields such as renewable energy technology, electronic industry and aerospace science. However, conventional relatively rough synthetic strategies will lead to either diminished magnetic properties or irregular morphology, which hindered their wide applications. In this article, we present a facile chemical approach to prepare 200 nm single domain SmCo5@Co core/shell magnets with coercivity of 20.7 kOe and saturation magnetization of 82 emu/g. We found that the incorporation of GO sheets is responsible for the generation of the unique structure. The single domain SmCo5 core contributes to the large coercivity of the magnets and the exchange-coupled Co shell enhances the magnetization. This method can be further utilized in the synthesis other Sm-Co based exchange-coupled magnets. PMID:24356309

  6. Gale Crater Mound

    NASA Technical Reports Server (NTRS)

    2003-01-01

    [figure removed for brevity, see original site]

    The eroded, layered deposit in Gale Crater is a mound of material rising 3 km above the crater floor. It has been sculpted by wind and possibly water to produce the dramatic landforms seen today. The origin of the sedimentary material that composes the mound remains a contested issue: was it produced from sedimentation in an ancient crater lake or by airfall onto dry land?

    Note: this THEMIS visual image has not been radiometrically nor geometrically calibrated for this preliminary release. An empirical correction has been performed to remove instrumental effects. A linear shift has been applied in the cross-track and down-track direction to approximate spacecraft and planetary motion. Fully calibrated and geometrically projected images will be released through the Planetary Data System in accordance with Project policies at a later time.

    NASA's Jet Propulsion Laboratory manages the 2001 Mars Odyssey mission for NASA's Office of Space Science, Washington, D.C. The Thermal Emission Imaging System (THEMIS) was developed by Arizona State University, Tempe, in collaboration with Raytheon Santa Barbara Remote Sensing. The THEMIS investigation is led by Dr. Philip Christensen at Arizona State University. Lockheed Martin Astronautics, Denver, is the prime contractor for the Odyssey project, and developed and built the orbiter. Mission operations are conducted jointly from Lockheed Martin and from JPL, a division of the California Institute of Technology in Pasadena.

    Image information: VIS instrument. Latitude -5.1, Longitude 137.5 East (222.5 West). 19 meter/pixel resolution.

  7. 4-H Club Goat Guide.

    ERIC Educational Resources Information Center

    Brown, R. Kipp

    This guide provides information for 4-H Club members who have decided on a club goat project. Topics include general information in the following areas: show rules; facilities and equipment (barns/sheds, fences, feeders, water containers, and equipment); selection (structural correctness, muscle, volume and capacity, style and balance, and growth…

  8. Seismic features of Winnipegosis mounds in Saskatchewan

    SciTech Connect

    Gendzwill, D.J.

    1988-07-01

    The Winnipegosis Formation of southern Saskatchewan is characterized by reefs or reeflike mounds in its upper member. Several characteristic features of the mounds permit their identification from seismic-reflection data. These features include reflections from the flanks of the mound, a change in the reflection continuity in the middle and base of the mound, a velocity pullup under the mound, and subsidence of strata over the mound. Dissolution of the salt which surrounds the mounds sometimes occurs, resulting in a drape structure. Some or all of these features may be present at the correct seismic stratigraphic level for Winnipegosis mounds, depending on the local conditions. Subsidence of strata over the mounds indicates compaction and porosity loss from the original mound or possibly the degree of dolomitization or pressure dissolution. Salt-removal features over or adjacent to the mounds indicate fluid movements. Approximate ages can be estimated from stratigraphic thinning and thickening relationships above such features. Complications in identifying Winnipegosis mounds may arise from thin-bed effects if the mounds are not very thick compared to a seismic wavelength. Confusion may also arise from anhydrite, which may encase the mounds or which may form a thick horizontal layer at the tops of the mounds, causing an interfering signal.

  9. Bizarre Crater Mound

    NASA Technical Reports Server (NTRS)

    2003-01-01

    [figure removed for brevity, see original site]

    Released 5 June 2003

    The height of the interior mound of sediment inside this crater exceeds the crater rim heights by 900 meters (3,000 ft). This is a confounding problem. How does all this material get inside this crater and actually rise higher than its holding chamber? What is this material? Where did it come from? Why is it still here? It is exactly these kinds of enigmas that makes Mars so very interesting.

    Image information: VIS instrument. Latitude 12.2, Longitude 26.3 East (333.7 West). 19 meter/pixel resolution.

    Note: this THEMIS visual image has not been radiometrically nor geometrically calibrated for this preliminary release. An empirical correction has been performed to remove instrumental effects. A linear shift has been applied in the cross-track and down-track direction to approximate spacecraft and planetary motion. Fully calibrated and geometrically projected images will be released through the Planetary Data System in accordance with Project policies at a later time.

    NASA's Jet Propulsion Laboratory manages the 2001 Mars Odyssey mission for NASA's Office of Space Science, Washington, D.C. The Thermal Emission Imaging System (THEMIS) was developed by Arizona State University, Tempe, in collaboration with Raytheon Santa Barbara Remote Sensing. The THEMIS investigation is led by Dr. Philip Christensen at Arizona State University. Lockheed Martin Astronautics, Denver, is the prime contractor for the Odyssey project, and developed and built the orbiter. Mission operations are conducted jointly from Lockheed Martin and from JPL, a division of the California Institute of Technology in Pasadena.

  10. 4-H in the 70's.

    ERIC Educational Resources Information Center

    Extension Service (USDA), Washington, DC.

    Developed under the leadership of the 1970 and 1971 Extension Committee on Organization and Policy 4-H Youth Subcommittees, the brochure offers a statement of potential and new directions for Extension 4-H youth programs. Opening sections deal with the functions of 4-H and balanced 4-H program expansion to serve seven million youth. Succeeding…

  11. Mound calorimetry for explosive surveillance

    SciTech Connect

    Shockey, G.C.; Rodenburg, W.W.

    1985-01-01

    Heat of reaction determinations of pyrotechnics and explosives is made at MRC-Mound by bomb calorimetry. Energy releases from ten calories to 94 kilocalories have been measured accurately using four different calorimeter systems. Each system is described and some heat of reaction results are given. 3 figs., 4 tabs.

  12. Paleoenvironmental setting of Paleozoic mud mounds

    SciTech Connect

    Wanless, H.R. . Dept. Geological Sciences); Tedesco, L.P. )

    1992-01-01

    Paleozoic carbonate mud mounds formed above storm wave base, which in many settings was in moderate to extremely shallow water. This is concluded by a comparative analysis of sedimentary structures, fabrics and small scale sequences occurring in Mississippian and Pennsylvanian mounds and in modern mud mounds and Halimeda bioherms. Most small mounds studied contain a shallowing sequence that represents shallowing into the zone of daily agitation. The bulk of each mound sequence is detrital deposition of layered mudstones to wackestones in the mound core and packstones to grainstones on the flanks and shoal cap. If macroskeletal fauna and flora are present, an autochthonous skeletal packstone may occur in the upper portion of the shallowing sequence beneath the detrital grainstone cap. Burrow excavations and grainy tubular tempestite infillings partially to completely modify the primary depositional fabric of all of these facies. Larger mounds studied are a composite of several to numerous smaller mound depositional sequences. High vertical relief of some larger mounds may be more the result of continued accommodation space provided by subsidence/downfaulting than be deposition in extremely deep water. Although the biotic components of carbonate mounds vary greatly through the Paleozoic, the contained sedimentary structures, fabrics and fundamental depositional sequences remain very similar. This suggests a general similarity in the mechanism and depositional setting of mound formation.

  13. Astronomical Aspects of Krakow's Monumental Mounds

    NASA Astrophysics Data System (ADS)

    Kozakiewicz, Joanna

    2015-05-01

    Krakus' mound and Wanda's mound are the largest prehistoric mounds in the region. According to the legend, they were raised by prehistoric Slavs as the burial sites of Krakow's founder - Krakus (or Krak), and his daughter - Wanda. Archaeological excavations have only been conducted on the mound of Krakus. They revealed that the mound was erected not earlier than the 1st century AD and not later than the 10th century AD. Furthermore, the studies conducted in the 1970s by professor Kotlarczyk showed that the azimuth connecting these mounds points to the sunrise on 1 May. As this day marks an important festival in the Celtic calendar - Beltaine - the two mounds could be related to the Celtic culture. This study presents the findings of the latest research.

  14. Adult 4-H Volunteer Empowerment in 4-H Youth Development Settings

    ERIC Educational Resources Information Center

    Olsen, Pamela

    2009-01-01

    The primary purpose of this study was to determine which factors related to adult 4-H volunteer empowerment in 4-H youth development settings. This study examined the relationship of adult 4-H volunteers' perceived leadership styles of Oregon 4-H Youth Development Educators (YDE) to the adult 4-H volunteer sense of empowerment. In addition,…

  15. Engaging Library Partners in 4-H Programming

    ERIC Educational Resources Information Center

    Fields, Nia Imani; Rafferty, Elizabeth

    2012-01-01

    When most people think about 4-H, they remember county fairs, livestock programs, and agricultural education. While these programs are still prominent, 4-H has grown in order to meet the growing demands of today's youth. The organization has expanded services and programs to serve rural, suburban, and urban youth in every state in the U.S. 4-H is…

  16. Strengthening 4-H by Analyzing Enrollment Data

    ERIC Educational Resources Information Center

    Hamilton, Stephen F.; Northern, Angela; Neff, Robert

    2014-01-01

    The study reported here used data from the ACCESS 4-H Enrollment System to gain insight into strengthening New York State's 4-H programming. Member enrollment lists from 2009 to 2012 were analyzed using Microsoft Excel to determine trends and dropout rates. The descriptive data indicate declining 4-H enrollment in recent years and peak…

  17. Martian Sedimentary Basins and Central Mound Formation

    NASA Astrophysics Data System (ADS)

    Bennett, K. A.; Bell, J. F., III

    2014-12-01

    Central mounds on Mars are observed as sedimentary deposits within crater interiors, but the specific processes responsible for their formation and subsequent modification are still debated. The deposits are hypothesized to have been created by either subaerial or subaqueous processes through one of two general formation mechanisms. The prevailing hypothesis suggests that after their craters were formed, sediment filled the entire crater and was later eroded into the morphologies we observe today. Alternatively, the sediment could have been deposited as the features we observe today without any significant erosion contributing to their mound shape. We conducted a survey of central mounds that occur within craters larger than 25 km in diameter located between ± 60° latitude on Mars. We use mound locations, mound offsets within their host craters, and mound heights to address various mound formation hypotheses. The results of this survey support the hypothesis that mound sediment once filled the entire host crater and was later eroded into the features we observe today. We propose that large Martian impact craters act as simplistic sedimentary basins. These basins "catch" any sediment that is being transported through the region. Any geologic process that involves transport of material (airfall dust, explosive volcanism, impact ejecta, etc.) could have contributed to the growth of this sediment fill, although the dominant process could vary based on location. During this depositional phase, several processes (ice/frost, water, etc.) could have cemented the material; then, at some point, the environment changed from depositional to erosional, leading to the formation of isolated mounds of sediment within these craters. Our study reveals that most mounds are offset from the center of their host crater in the same direction as the regional winds. For example, the mounds in Arabia Terra are offset towards the western portion of their craters. This observation is

  18. Air sparging: Much ado about mounding

    SciTech Connect

    Lundegard, P.D.

    1995-12-31

    Groundwater mounding is the upward movement of the water table that can occur in association with air injection into the saturated zone. Multiphase flow simulations are here used to define general mounding behavior and dynamics under simplified subsurface conditions. Field observations at three sites are then used to describe a range of expected groundwater mounding responses for subsurface conditions, ranging from relatively homogeneous to highly heterogeneous. Results show that mounding (1) is a transient response that is usually negligible at steady state, (2) dissipates by radial wavelike spreading, and (3) occurs well beyond the saturated zone region of airflow.

  19. 4-H Clover Awareness Teaching Guide.

    ERIC Educational Resources Information Center

    Rutherford, Barbara; Leach, Jennifer

    The purpose of this teaching guide is to introduce children in grades 1-4 and their parents to the 4-H program without the long-term commitment of the traditional 4-H club. The 4-H Clover Awareness Program was designed as an after-school program; however, it could be used in other settings such as a day camp. In addition to introducing children to…

  20. The Toddler: 4-H Child Development Project.

    ERIC Educational Resources Information Center

    Francis, Connie M.

    Part of a series for 4-H members between 9 and 19 years of age, this age-graded guide is designed to help children and adolescents: (1) understand the toddler's physical, mental, social, and emotional growth; (2) learn to care for a toddler; and (3) choose types of play that toddlers enjoy. Contents include suggestions on projects that 4-H members…

  1. Strengthening 4-H Program Communication through Technology

    ERIC Educational Resources Information Center

    Robideau, Kari; Santl, Karyn

    2011-01-01

    Advances in technology are transforming how youth and parents interact with programs. The Strengthening 4-H Communication through Technology project was implemented in eight county 4-H programs in Northwest Minnesota. This article outlines the intentional process used to effectively implement technology in program planning. The project includes:…

  2. Community Development: A 4-H Intern Report.

    ERIC Educational Resources Information Center

    Scheneman, C. Stephen

    State progress reports on the 4-H/Community Development program, a 1973 nationwide Federally sponsored program facilitating youth in community decision-making processes, indicate that the program appears to be evolving into a viable and integral part of the total 4-H program. Although the report describes unique program features of various States,…

  3. Geological mounds and their seismic expression

    SciTech Connect

    Swarbrick, R.E. )

    1991-03-01

    Mound geometry (convex upward structure developed above a subhorizontal surface) is common in many geological environments and frequently observed in 2-dimensions on seismic sections. Seismic mounds are typically associated with deep-water clastic sediments, e.g. submarine fans and slumps, and with a variety of carbonate depositional settings, e.g., reefs and banks, but also exist in other depositional settings. Recognition will be dependent on mound dimension, velocity contrast, amplitude strength, and the resolution of the seismic data. Since mounds can represent an important exploration target and recognition of porous, hydrocarbon-bearing section is all-important, careful restitution of the original depositional morphology from the seismic data is required. Details of present velocity distribution are critical, along with a realistic concept of any post-depositional modification, such as compaction, which may have taken place during burial. Where differential compaction is taking place, for example between sand and shale, seismic expression of morphology will be continually modified during progressive burial. Analysis of structure at the top and base of the mound can provide support for lithological interpretation based on other criteria, such as seismic facies analysis based on internal and external reflections. Modeling, using parameters from mounds in a variety of known depositional settings, illustrates many of the interpretational problems associated with seismic mounds and provides some objective criteria for analysis of mound morphology. Comparison is made with real data, principally from northwest Europe and North America.

  4. Sulphur Extraction at Bryan Mound

    SciTech Connect

    Kirby, Carolyn L; Lord, Anna C. Snider

    2015-08-01

    The Bryan Mound caprock was subjected to extens ive sulphur mining prior to the development of the Strategic Petroleum Reserve. Undoubtedl y, the mining has modified the caprock integrity. Cavern wells at Bryan Mound have been subject to a host of well integr ity concerns with many likely compromised by the cavernous capro ck, surrounding corrosive environment (H 2 SO 4 ), and associated elevated residual temperatures al l of which are a product of the mining activities. The intent of this study was to understand the sulphur mining process and how the mining has affected the stability of the caprock and how the compromised caprock has influenced the integrity of the cavern wells. After an extensiv e search to collect pert inent information through state agencies, literature sear ches, and the Sandia SPR librar y, a better understanding of the caprock can be inferred from the knowledge gaine d. Specifically, the discovery of the original ore reserve map goes a long way towards modeling caprock stability. In addition the gained knowledge of sulphur mining - subs idence, superheated corrosive wa ters, and caprock collapse - helps to better predict the post mi ning effects on wellbore integrity. This page intentionally left blank

  5. Scaling law for Dictyostelium Discoideum mounds

    NASA Astrophysics Data System (ADS)

    Voeltz, Camilla; Bodenschatz, Eberhard

    2004-03-01

    Little is known about how multicellular organisms regulate the size of their tissues during development. The eukaryote Dictyostelium Discoideum, may be studied as a model system. When starved, these amoebae aggregate and form cell mounds. These mounds develop into moving slugs and fruiting bodies consisting of a spore mass held atop a rigid stem of stalk cells. We report experiments on the development of mounds of Dicty-cells when confined to different heights. At the smallest height the amoebae are confined to a monolayer of cells in a 2d-plane. We found that the confinement inhibited the development of moving slugs and fruiting bodies. The cells aggregated and formed mounds whose size was found to be proportional to the height of the mounds. The precise mechanism is yet unknown. We will present the data and discuss possible mechanisms. This work is supported by the NSF through the Biocomplexity Program.

  6. COCARDE: new view on old mounds - an international network of carbonate mound research

    NASA Astrophysics Data System (ADS)

    Rüggeberg, A.; Foubert, A.; Vertino, A.; van Rooij, D.; Spezzaferri, S.; Henriet, J.-P.; Dullo, W.-C.; Cocarde Science Community

    2012-04-01

    Carbonate mounds are important contributors of life in different settings, from warm-water to cold-water environments, and throughout geological history. Research on modern cold-water coral carbonate mounds over the last decades made a major contribution to our overall understanding of these particular sedimentary systems. By looking to the modern carbonate mound community with cold-water corals as main framework builders, some fundamental questions could be addressed, until now not yet explored in fossil mound settings. The international network COCARDE (http://www.cocarde.eu) is a platform for exploring new insights in carbonate mound research of recent and ancient mound systems. The aim of the COCARDE network is to bring together scientific communities, studying Recent carbonate mounds in midslope environments in the present ocean and investigating fossil mounds spanning the whole Phanerozoic time, respectively. Scientific challenges in modern and ancient carbonate mound research got well defined during the ESF Magellan Workshop COCARDE in Fribourg, Switzerland (21.-24.01.2009). The Special Volume Cold-water Carbonate Reservoir systems in Deep Environments - COCARDE (Marine Geology, Vol. 282) was the major outcome of this meeting and highlights the diversity of Recent carbonate mound studies. The following first joint Workshop and Field Seminar held in Oviedo, Spain (16.-20.09.2009) highlighted ongoing research from both Recent and fossil academic groups integrating the message from the industry. The field seminar focused on mounds from the Carboniferous platform of Asturias and Cantabria, already intensively visited by industrial and academic researchers. However, by comparing ancient, mixed carbonate-siliciclastic mound systems of Cantabria with the Recent ones in the Porcupine Seabight, striking similarities in their genesis and processes in mound development asked for an integrated drilling campaign to understand better the 3D internal mound build-up. The

  7. Relationships between 4-H Volunteer Leader Competencies and Skills Youth Learn in 4-H Programs

    ERIC Educational Resources Information Center

    Radhakrishna, Rama; Ewing, John C.

    2011-01-01

    This article examined the relationships between 4-H volunteer leader competencies and skills youth learn in 4-H. Using a descriptive-correlational research, the study reported found significant relationships between leadership competencies and skills youth learn in 4-H. Regression analysis revealed that two variables--skills and…

  8. Middle Childhood: 4-H Child Development Project.

    ERIC Educational Resources Information Center

    Francis, Connie M.

    Part of a series for 4-H members between 9 and 19 years of age, this age-graded guide to the development of 6-, 7-, and 8-year-olds aims to help 4-H members who are children and adolescents themselves: (1) understand the physical, mental, social, and emotional development of children in middle childhood; (2) learn to care for a child in middle…

  9. Thermoregulation and ventilation of termite mounds

    NASA Astrophysics Data System (ADS)

    Korb, Judith

    2003-05-01

    Some of the most sophisticated of all animal-built structures are the mounds of African termites of the subfamily Macrotermitinae, the fungus-growing termites. They have long been studied as fascinating textbook examples of thermoregulation or ventilation of animal buildings. However, little research has been designed to provide critical tests of these paradigms, derived from a very small number of original papers. Here I review results from recent studies on Macrotermes bellicosus that considered the interdependence of ambient temperature, thermoregulation, ventilation and mound architecture, and that question some of the fundamental paradigms of termite mounds. M. bellicosus achieves thermal homeostasis within the mound, but ambient temperature has an influence too. In colonies in comparably cool habitats, mound architecture is adapted to reduce the loss of metabolically produced heat to the environment. While this has no negative consequences in small colonies, it produces a trade-off with gas exchange in large colonies, resulting in suboptimally low nest temperatures and increased CO2 concentrations. Along with the alteration in mound architecture, the gas exchange/ventilation mechanism also changes. While mounds in the thermally appropriate savannah have a very efficient circular ventilation during the day, the ventilation in the cooler forest is a less efficient upward movement of air, with gas exchange restricted by reduced surface exchange area. These results, together with other recent findings, question entrenched ideas such as the thermosiphon-ventilation mechanism or the assumption that mounds function to dissipate internally produced heat. Models trying to explain the proximate mechanisms of mound building, or building elements, are discussed.

  10. Thermoregulation and ventilation of termite mounds.

    PubMed

    Korb, Judith

    2003-05-01

    Some of the most sophisticated of all animal-built structures are the mounds of African termites of the subfamily Macrotermitinae, the fungus-growing termites. They have long been studied as fascinating textbook examples of thermoregulation or ventilation of animal buildings. However, little research has been designed to provide critical tests of these paradigms, derived from a very small number of original papers. Here I review results from recent studies on Macrotermes bellicosus that considered the interdependence of ambient temperature, thermoregulation, ventilation and mound architecture, and that question some of the fundamental paradigms of termite mounds. M. bellicosus achieves thermal homeostasis within the mound, but ambient temperature has an influence too. In colonies in comparably cool habitats, mound architecture is adapted to reduce the loss of metabolically produced heat to the environment. While this has no negative consequences in small colonies, it produces a trade-off with gas exchange in large colonies, resulting in suboptimally low nest temperatures and increased CO(2) concentrations. Along with the alteration in mound architecture, the gas exchange/ventilation mechanism also changes. While mounds in the thermally appropriate savannah have a very efficient circular ventilation during the day, the ventilation in the cooler forest is a less efficient upward movement of air, with gas exchange restricted by reduced surface exchange area. These results, together with other recent findings, question entrenched ideas such as the thermosiphon-ventilation mechanism or the assumption that mounds function to dissipate internally produced heat. Models trying to explain the proximate mechanisms of mound building, or building elements, are discussed.

  11. Synthesis of 4H/fcc Noble Multimetallic Nanoribbons for Electrocatalytic Hydrogen Evolution Reaction.

    PubMed

    Fan, Zhanxi; Luo, Zhimin; Huang, Xiao; Li, Bing; Chen, Ye; Wang, Jie; Hu, Yanling; Zhang, Hua

    2016-02-01

    Noble multimetallic nanomaterials, if only consisting of Au, Ag, Pt, and Pd, typically adopt the high-symmetry face-centered cubic (fcc) structure. Here for the first time, by using the 4H/fcc Au@Ag nanoribbons (NRBs) as seeds, we report the synthesis of 4H/fcc trimetallic Au@PdAg core-shell NRBs via the galvanic reaction method under ambient conditions. Moreover, this strategy can also be used to synthesize 4H/fcc trimetallic Au@PtAg and quatermetallic Au@PtPdAg core-shell NRBs. Impressively, for the first time, these alloy shells, i.e., PdAg, PtAg, and PtPdAg, epitaxially grown on the 4H/fcc Au core with novel 4H hexagonal phase were successfully synthesized. Remarkably, the obtained 4H/fcc Au@PdAg NRBs exhibit excellent electrocatalytic activity toward the hydrogen evolution reaction, which is even quite close to that of the commercial Pt black. We believe that our findings here may provide a novel strategy for the crystal-structure-controlled synthesis of advanced functional noble multimetallic nanomaterials with various promising applications.

  12. Formation of Mima mounds: A seismic hypothesis

    SciTech Connect

    Berg, A.W. )

    1990-03-01

    Mima mounds approximately 2.5 to 15 m in diameter and up to 3 m high occur on the ground surfaces at Mima Prairie, south of Olympia, Washington, in the Channeled Scabland of eastern Washington, and at many other locations in the United States and around the world. Small-scale Mima mounds can be produced experimentally by subjecting a plywood board covered with a thin veneer of loess to impacts that produce vibrations in the board. Experimentally produced mounds have characteristics that are nearly identical to those found in the field. This suggests that most Mima mounds formed as the result of seismic activity in conjunction with unconsolidated fine sediments on a relatively rigid planar substratum.

  13. Thermal Analysis of the Mound One Kilowatt Package

    SciTech Connect

    Or, Chuen T.

    1993-01-01

    The Mound One Kilowatt (1 KW) package was designed for the shipment of plutonium (Pu-238) with not more than 1 kW total heat dissipation. To comply with regulations, the Mound 1 kW package has to pass all the requirements under Normal Conditions of Transport (NCT; 38 degrees C ambient temperature) and Hypothetical Accident Conditions (HAC; package engulfed in fire for 30 minutes). Analytical and test results were presented in the Safety Analysis Report for Packaging (SARP) for the Mound 1 kW package, revision 1, April 1991. Some issues remained unresolved in that revision. In March 1992, Fairchild Space and Defense Corporation was commissioned by the Department of Energy to perform the thermal analyses. 3-D thermal models were created to perform the NCT and HAC analyses. Four shipping configurations in the SARP revision 3 were analyzed. They were: (1) The GPHS graphite impact shell (GIS) in the threaded product can (1000 W total heat generation); (2) The fueled clads in the welded product can (1000 W total heat generation); (3) The General Purpose Heat Source (GPHS) module (750 W total heat generation); and (4) The Multi-Hundred Watt (MHW) spheres (810 W total heat generation). Results from the four cases show that the GIS or fuel clad in the product can is the worse case. The temperatures predicted under NCT and HAC in all four cases are within the design limits. The use of helium instead of argon as cover gas provides a bigger safety margin. There is a duplicate copy.

  14. Groundwater Mounding Beneath Stormwater Infiltration Basins

    NASA Astrophysics Data System (ADS)

    Nimmer, M.; Thompson, A. M.; Misra, D.

    2007-12-01

    An accurate understanding of groundwater mound formation is important in the proper design of stormwater infiltration basins since these basins are often required to recharge a portion of pre-development infiltration volume. Mound formation due to localized recharge may reduce the infiltration rate of the basin and the ability of the soil to filter pollutants. The goal of this research was to understand groundwater mounding and the potential for contaminant transport resulting from recharge beneath stormwater infiltration basins. A 0.10 ha infiltration basin serving a 9.4 ha residential subdivision in Oconomowoc, Wisconsin was used in this study. Subsurface conditions included sand and gravel material and a groundwater table at 2.3 m below grade. Three storm events, 4.9 cm, 2.8 cm, and 4.3 cm, between August 2006 and April 2007 were modeled using the two-dimensional numerical model HYDRUS. The calibrated model was used to evaluate hypothetical basin operation scenarios for various basin sizes, soil types, ponding depths, and water table depths. The groundwater mound intersected the basin floor in most scenarios with loamy sand and sandy loam soils, an unsaturated thickness of 1.52 m, and a ponding depth of 0.61 m. No groundwater table response was observed with ponding depths less than 0.31 m with an unsaturated zone thickness of 6.09 m. The mound height was most sensitive to hydraulic conductivity and unsaturated zone thickness. A 7.6 cm sediment layer delayed the time to reach maximum mound height, but had a minimal effect on the magnitude of the mound. Mound heights increased as infiltration basin size increased.

  15. 4-H Textile Science Beginner Projects.

    ERIC Educational Resources Information Center

    Scholl, Jan

    This packet contains three 4-H projects for students beginning the sewing sequence of the textile sciences area. The projects cover basics of sewing using sewing machines, more difficult sewing machine techniques, and hand sewing. Each project provides an overview of what the student will learn, what materials are needed, and suggested projects…

  16. Multi-state 4-H energy program

    SciTech Connect

    Bakker, U.B.; Garthe, J.W.

    1983-06-01

    Through Agricultural Engineering 4-H Energy Programs, youth can be educated to gain knowledge, increase hands on skills, and incorporate energy-saving techniques into their lifestyle. In a pilot multi-state energy program tested by 13 states, youth increased their energy awareness.

  17. 4-H for Central City Minorities

    ERIC Educational Resources Information Center

    Paige, Joseph C.

    1970-01-01

    Joseph C. Paige is the Dean of Community Education and Director of Cooperative Extension Service of the only urban Land-Grant College, Federal City College, in Washington, D.C. Here he is interviewed about 4-H with children of poor ethnic groups in the District of Columbia. (NL)

  18. The Preschooler: 4-H Child Development Project.

    ERIC Educational Resources Information Center

    Francis, Connie M.

    Intended for 4-H participants who plan and implement activities in the area of child development, this booklet provides a study guide to help young learners: (1) gain understanding of a preschool child's physical, mental, social, and emotional growth; (2) learn to care for a preschooler and promote preschoolers' feelings of security and safety;…

  19. The Infant: 4-H Child Development Project.

    ERIC Educational Resources Information Center

    Francis, Connie M.

    This booklet for 4-H members who elect to undertake projects in child caregiving provides guidelines and information that help children and adolescents between 9 and 19 years of age: (1) understand infants' physical, mental, social, and emotional growth; (2) learn to care for a baby and promote feelings of security and safety; and (3) choose types…

  20. Separates. 4-H Textile Science Advanced Project.

    ERIC Educational Resources Information Center

    Scholl, Jan F.

    This booklet, which was developed for use by 4-H club members in Pennsylvania, contains the information required to sew a two-piece nontailored outfit and/or a one-or two-piece dress. The following are among the topics covered: the difference between a fiber and a fabric; properties of different fibers and fabrics; common jacket, neckline, sleeve,…

  1. 4-H Science Inquiry Video Series

    ERIC Educational Resources Information Center

    Green, Jeremy W.; Black, Lynette; Willis, Patrick

    2013-01-01

    Studies support science inquiry as a positive method and approach for 4-H professionals and volunteers to use for teaching science-based practices to youth. The development of a science inquiry video series has yielded positive results as it relates to youth development education and science. The video series highlights how to conduct science-rich…

  2. Effectiveness of the 4-H Program as Perceived by Parents of 4-H Participants

    ERIC Educational Resources Information Center

    Radhakrishna, Rama; Foley, Caitlin; Ingram, Patreese; Ewing, John C.

    2013-01-01

    The study reported here examined the effectiveness of 4-H program as perceived by parents of program participants. Descriptive-correlational design was employed, with data collected using a mail survey. Parents perceived 4-H as an effective organization in teaching life skills to youth. Significant relationships were found between parents'…

  3. National 4-H Common Measures: Initial Evaluation from California 4-H

    ERIC Educational Resources Information Center

    Lewis, Kendra M.; Horrillo, Shannon J.; Widaman, Keith; Worker, Steven M.; Trzesniewski, Kali

    2015-01-01

    Evaluation is a key component to learning about the effectiveness of a program. This article provides descriptive statistics of the newly developed National 4-H Common Measures (science, healthy living, citizenship, and youth development) based on data from 721 California 4-H youth. The measures were evaluated for their reliability and validity of…

  4. Preliminary Results from IODP Expedition 307, Porcupine Basin Carbonate Mounds

    NASA Astrophysics Data System (ADS)

    Williams, T.; Kano, A.; Ferdelman, T.; Henriet, J.; Shipboard Scientific Party, I.

    2005-12-01

    IODP Expedition 307 (April 26 - May 16, 2005) drilled three sites at Challenger Mound in the Porcupine Seabight, west of Ireland. Deep-water carbonate mounds up to 2 km wide and 200 m high have been found in typical water depths of 500-1000 m along the continental slope of NW Europe from Morocco to Norway. During the last ten years they have been studied using seismics, shallow coring, high resolution bathymetry, and remotely operated vehicles. The partly-buried Challenger Mound is the first to be completely cored to the mound base, with the aim of answering basic questions such as: What is the sedimentology and structure of the mound? What triggered mound initiation? How does the ecosystem interact with sedimentary fluxes to make the mound grow? How are mound growth phases related to glacial-interglacial cycles? What role do microbial communities and geochemical reaction play in the mound? Analytical work is at an early stage, but already shipboard results reveal some of the mound's secrets. The mound body consists of a 155-m-thick sequence of cold-water coral-bearing Pleistocene sediments (floatstone, rudstone, and wackestone), characterized by 10-meter-scale alternation of light gray and dark green intervals. The carbonate-rich and light-colored layers are partially lithified and feature poor coral preservation or even dissolution. The mound base, virtually identical in the on-mound and off-mound holes, is a sharp Pliocene erosional unconformity, separating coral-bearing sediments from a glauconitic and partly sandy siltstone. No evidence was found for a relation between mound development and hydrocarbon seepage. The results from Challenger Mound will help provide a depositional model with which to interpret deep water carbonate mounds in the geological rock record, and we look forward to future drilling of contrasting carbonate mounds.

  5. VIBRATIONALLY EXCITED C{sub 4}H

    SciTech Connect

    Cooksy, Andrew L.; Gottlieb, C. A.; Thaddeus, P.; Patel, Nimesh A.; Young, Ken H.; McCarthy, M. C.; Killian, T. C.

    2015-02-01

    Rotational spectra in four new excited vibrational levels of the linear carbon chain radical C{sub 4}H were observed in the millimeter band between 69 and 364 GHz in a low pressure glow discharge, and two of these were observed in a supersonic molecular beam between 19 and 38 GHz. All have rotational constants within 0.4% of the X{sup 2}Σ{sup +} ground vibrational state of C{sub 4}H and were assigned to new bending vibrational levels, two each with {sup 2}Σ and {sup 2}Π vibrational symmetry. The new levels are tentatively assigned to the 1ν{sub 6} and 1ν{sub 5} bending vibrational modes (both with {sup 2}Π symmetry), and the 1ν{sub 6}+1ν{sub 7} and 1ν{sub 5}+1ν{sub 6} combination levels ({sup 2}Σ symmetry) on the basis of the derived spectroscopic constants, relative intensities in our discharge source, and published laser spectroscopic and quantum calculations. Prior spectroscopic constants in the 1ν{sub 7} and 2ν{sub 7} levels were refined. Also presented are interferometric maps of the ground state and the 1ν{sub 7} level obtained with the Submillimeter Array (SMA) near 257 GHz which show that C{sub 4}H is present near the central star in IRC+10216. We found no evidence with the SMA for the new vibrationally excited levels of C{sub 4}H at a peak flux density averaged over a 3{sup ′′} synthesized beam of ⩾0.15 Jy/beam in the 294–296 and 304–306 GHz range, but it is anticipated that rotational lines in the new levels might be observed in IRC+10216 when ALMA attains its full design capability.

  6. Learnings and Recommendations to Advance 4-H Science Readiness

    ERIC Educational Resources Information Center

    Schmitt-McQuitty, Lynn; Carlos, Ramona; Smith, Martin H.

    2014-01-01

    The case study investigation reported here assessed California 4-H professionals' understanding of the essential components of effective 4-H Science programming as established by the National 4-H Science Mission Mandate. Using the 4-H Science Checklist as the basis for defining 4-H Science Readiness, academic and program staff were surveyed…

  7. The DeKalb mounds of northeastern Illinois as archives of deglacial history and postglacial environments

    NASA Astrophysics Data System (ADS)

    Curry, B. Brandon; Konen, Michael E.; Larson, Timothy H.; Yansa, Catherine H.; Hackley, Keith C.; Alexanderson, Helena; Lowell, Thomas V.

    2010-07-01

    The "type" DeKalb mounds of northeastern Illinois, USA (42.0°N, -88.7°W), are formed of basal sand and gravel overlain by rhythmically bedded fines, and weathered sand and gravel. Generally from 2 to 7 m thick, the fines include abundant fossils of ostracodes and uncommon leaves and stems of tundra plants. Rare chironomid head capsules, pillclam shells, and aquatic plant macrofossils also have been observed. Radiocarbon ages on the tundra plant fossils from the "type" region range from 20,420 to 18,560 cal yr BP. Comparison of radiocarbon ages of terrestrial plants from type area ice-walled lake plains and adjacent kettle basins indicate that the topographic inversion to ice-free conditions occurred from 18,560 and 16,650 cal yr BP. Outside the "type" area, the oldest reliable age of tundra plant fossils in DeKalb mound sediment is 21,680 cal yr BP; the mound occurs on the northern arm of the Ransom Moraine (-88.5436°W, 41.5028°N). The youngest age, 16,250 cal yr BP, is associated with a mound on the Deerfield Moraine (-87.9102°W, 42.4260°N) located about 9 km east of Lake Michigan. The chronology of individual successions indicates the lakes persisted on the periglacial landscape for about 300 to 1500 yr.

  8. Mound-Interface Kinetics in Dictyostelium Aggregation

    NASA Astrophysics Data System (ADS)

    Tutu, Hiroki

    2002-09-01

    The mound development of the cellular slime mold amoebae Dictyostelium discoideum is studied with an interface kinetic model for the height of cell layers. As a competitive role for the chemotaxis, we compare two types of curvature relaxations; the surface relaxation induced by cell-substrate affinity (model A), and that comes from a cell-cell adhesive effect (model B). It is found that both models are characterized by the growth law for the maximum mound height. Based on a self-similarity scaling hypothesis for the spatial structure of streaming pattern, we suggest a scaling law for the growth of mound-height hmax ˜ t1-1/α+β/α with α = 2 (4) for the model A (B) and a number 0 ≤ β < 1.

  9. A global survey of martian central mounds: Central mounds as remnants of previously more extensive large-scale sedimentary deposits

    NASA Astrophysics Data System (ADS)

    Bennett, Kristen A.; Bell, James F.

    2016-01-01

    We conducted a survey of central mounds within large (>25 km diameter) impact craters on Mars. We use mound locations, mound offsets within their host craters, and relative mound heights to address and extend various mound formation hypotheses. The results of this survey support the hypothesis that mound sediments once filled their host craters and were later eroded into the features we observe today. The majority of mounds are located near the boundaries of previously identified large-scale sedimentary deposits. We discuss the implications of the hypothesis that central mounds are part of previously more extensive sedimentary units that filled and overtopped underlying impact craters. In this scenario, as erosion of the sedimentary unit occurred, the sediment within impact craters was preserved slightly longer than the overlying sediment because it was sheltered by the crater walls. Our study also reveals that most mounds are offset from the center of their host crater in the same direction as the present regional winds (e.g., the mounds in Arabia Terra are offset towards the western portion of their craters). We propose that this implies that wind has been the dominant agent causing the erosion of central mounds. Mound offset (r) is normalized to each crater's radius. The Mound offset (θ) is such that 0 is north and 270 is west.

  10. Interplay of instabilities in mounded surface growth

    SciTech Connect

    Chakrabarti, Buddhapriya; Dasgupta, Chandan

    2005-02-01

    We numerically study a one-dimensional conserved growth equation with competing linear (Ehrlich-Schwoebel) and nonlinear instabilities. As a control parameter is varied, this model exhibits a nonequilibrium phase transition between two mounded states, one of which exhibits slope selection and the other does not. The coarsening behavior of the mounds in these two phases is studied in detail. In the absence of noise, the steady-state configuration depends crucially on which of the two instabilities dominates the early time behavior.

  11. Three-dimensional sampling method for characterizing ant mounds

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A field-portable 3D laser scanner was employed as a means of digitizing the surface of fire ant (Solenopsis invicta Buren) mounds for analysis of shape and orientation in Mississippi and Oklahoma. Estimates of above-ground mound volume obtained through manual measurements of mound length, width, an...

  12. Dynamic Thermal Structure of Imported Fire Ant Mounds

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A study was undertaken to characterize surface temperatures of imported fire ant (Solenopsis invicta Buren, S. richteri Forel, and their hybrid) mounds as it relates to sun position and shape of the mounds, to better understand factors that affect absorption of solar radiation by the nest mound and ...

  13. From the Au nano-clusters to the nanoparticles on 4H-SiC (0001)

    PubMed Central

    Li, Ming-Yu; Zhang, Quanzhen; Pandey, Puran; Sui, Mao; Kim, Eun-Soo; Lee, Jihoon

    2015-01-01

    The control over the configuration, size, and density of Au nanoparticles (NPs) has offered a promising route to control the spatial confinement of electrons and photons, as a result, Au NPs with a various configuration, size and density are witnessed in numerous applications. In this work, we investigate the evolution of self-assembled Au nanostructures on 4H-SiC (0001) by the systematic variation of annealing temperature (AT) with several deposition amount (DA). With the relatively high DAs (8 and 15 nm), depending on the AT variation, the surface morphology drastically evolve in two distinctive phases, i.e. (I) irregular nano-mounds and (II) hexagonal nano-crystals. The thermal energy activates adatoms to aggregate resulting in the formation of self-assembled irregular Au nano-mounds based on diffusion limited agglomeration at comparatively low annealing temperature, which is also accompanied with the formations of hillocks and granules due to the dewetting of Au films and surface reordering. At high temperature, hexagonal Au nano-crystals form with facets along {111} and {100} likely due to anisotropic distribution of surface energy induced by the increased volume of NPs. With the small DA (3 nm), only dome shaped Au NPs are fabricated along with the variation of AT from low to elevated temperature. PMID:26354098

  14. From the Au nano-clusters to the nanoparticles on 4H-SiC (0001).

    PubMed

    Li, Ming-Yu; Zhang, Quanzhen; Pandey, Puran; Sui, Mao; Kim, Eun-Soo; Lee, Jihoon

    2015-01-01

    The control over the configuration, size, and density of Au nanoparticles (NPs) has offered a promising route to control the spatial confinement of electrons and photons, as a result, Au NPs with a various configuration, size and density are witnessed in numerous applications. In this work, we investigate the evolution of self-assembled Au nanostructures on 4H-SiC (0001) by the systematic variation of annealing temperature (AT) with several deposition amount (DA). With the relatively high DAs (8 and 15 nm), depending on the AT variation, the surface morphology drastically evolve in two distinctive phases, i.e. (I) irregular nano-mounds and (II) hexagonal nano-crystals. The thermal energy activates adatoms to aggregate resulting in the formation of self-assembled irregular Au nano-mounds based on diffusion limited agglomeration at comparatively low annealing temperature, which is also accompanied with the formations of hillocks and granules due to the dewetting of Au films and surface reordering. At high temperature, hexagonal Au nano-crystals form with facets along {111} and {100} likely due to anisotropic distribution of surface energy induced by the increased volume of NPs. With the small DA (3 nm), only dome shaped Au NPs are fabricated along with the variation of AT from low to elevated temperature.

  15. From the Au nano-clusters to the nanoparticles on 4H-SiC (0001).

    PubMed

    Li, Ming-Yu; Zhang, Quanzhen; Pandey, Puran; Sui, Mao; Kim, Eun-Soo; Lee, Jihoon

    2015-01-01

    The control over the configuration, size, and density of Au nanoparticles (NPs) has offered a promising route to control the spatial confinement of electrons and photons, as a result, Au NPs with a various configuration, size and density are witnessed in numerous applications. In this work, we investigate the evolution of self-assembled Au nanostructures on 4H-SiC (0001) by the systematic variation of annealing temperature (AT) with several deposition amount (DA). With the relatively high DAs (8 and 15 nm), depending on the AT variation, the surface morphology drastically evolve in two distinctive phases, i.e. (I) irregular nano-mounds and (II) hexagonal nano-crystals. The thermal energy activates adatoms to aggregate resulting in the formation of self-assembled irregular Au nano-mounds based on diffusion limited agglomeration at comparatively low annealing temperature, which is also accompanied with the formations of hillocks and granules due to the dewetting of Au films and surface reordering. At high temperature, hexagonal Au nano-crystals form with facets along {111} and {100} likely due to anisotropic distribution of surface energy induced by the increased volume of NPs. With the small DA (3 nm), only dome shaped Au NPs are fabricated along with the variation of AT from low to elevated temperature. PMID:26354098

  16. Mounds View Environmental Education Project, Report #1.

    ERIC Educational Resources Information Center

    Budde, Duane

    Prepared for the 1971 National Science Teachers Association (NSTA) Annual Meeting, this collection of ideas, activities, and unit plans from the Mounds View Environmental Education Project would be useful for junior and senior high school teachers and curriculum planners. Content includes: (1) a senior high course outline and daily lesson plans…

  17. Diurnal respiration of a termite mound

    NASA Astrophysics Data System (ADS)

    King, Hunter; Ocko, Samuel; Mahadevan, L.

    2014-11-01

    Many species of fungus-harvesting termites build largely empty, massive mound structures which protrude from the ground above their subterranean nests. It has been long proposed that the function of these mounds is to facilitate exchange of heat, humidity, and respiratory gases; this would give the colony a controlled climate in which to raise fungus and brood. However, the specific mechanism by which the mound achieves ventilation has remained a topic of debate, as direct measurement of internal air flows has remained difficult. By directly measuring these elusive, tiny flows with a custom sensor, we find that the mound architecture of the species Odontotermes obesus takes advantage of daily oscillations in ambient temperature to drive convection and gas transport. This contradicts previous theories, which point to internal metabolic heating and external wind as driving forces. Our result, a novel example of deriving useful work from a fluctuating scalar parameter, should contribute to better understanding insect swarm construction and possible development in passive human architecture, both of which have been spurred by previous research on termites. We acknowledge support from HFSP.

  18. Self-assembly of C4H-type hydrogenated graphene.

    PubMed

    Liu, Zilong; Xue, Qingzhong; Xing, Wei; Du, Yonggang; Han, Zhide

    2013-11-21

    We demonstrate by molecular dynamic (MD) simulations that patterned partially hydrogenated graphene (C4H) can self-assemble at room temperature. The main driving force of the self-assembly of C4H is due to the one-sided distribution of hydrogen and the corresponding asymmetric orientation of sp(3) bonding, there exists strong electrostatic repulsion between the relatively close H atoms. The simulations show that C4H can self-assemble into various carbon nanoscroll (CNS) structures, this is mainly controlled by its geometry (size and aspect ratio). And the carbon nanotube (CNT) is a good candidate to activate and guide C4H to form CNS, whose core size can be controlled. Meanwhile, a novel CNT/C4H core/shell composite nanostructure is also formed. The theoretical results shed important light on a feasible approach to fabricate high-quality CNS and other novel nanostructures including core/shell structures, which hold great potential applications in optics, optoelectronic devices, hydrogen storage, sensors, and energy storage in supercapacitors or batteries. PMID:24064528

  19. Mound site environmental report for calendar year 1991

    SciTech Connect

    Bauer, L.R.

    1992-06-01

    Mound is a government-owned facility operated by EG&G Mound Applied Technologies for the U.S. Department of Energy (DOE). This integrated production, development, and research site performs work in support of DOE`s weapon and energy related programs, with emphasis on explosive, nuclear, and energy technology. The purpose of this report is to inform the public about the impact of Mound`s operations on the population and the environment. This report summarizes data from the Environmental Monitoring Program, through which Mound maintains continuous surveillance of radiological and nonradiological substances released from the facility.

  20. Independent technical review of the Mound Plant

    SciTech Connect

    Not Available

    1994-06-01

    This report documents an Independent Technical Review (ITR) of the facilities, organizations, plans, and activities required to transition particular elements of the Mound Plant from Defense Program (DP) funded operation as appropriate either to community developed reuse or safe deactivation leading to decontamination and decommissioning (D&D). The review was conducted at the request of the Dr. Willis Bixby, Deputy Assistant Secretary, U.S. Department of Energy EM-60, Office of Facility Transition and Management and is a consensus of the nine member ITR Team. Information for the review was drawn from documents provided to the ITR Team by the Miamisburg Area Office (MB) of the DOE, EG&G, the City of Miamisburg, and others; and from presentations, discussions, interviews, and facility inspections at the Mound Plant during the weeks of March 14 and March 28, 1994. During the week of April 25, 1994, the ITR Team met at Los Alamos, New Mexico to develop consensus recommendations. A presentation of the core recommendations was made at the Mound Plant on May 5, 1994. This is an independent assessment of information available to, and used by, the Mound Plant personnel. Repetition of the information is not meant to imply discovery by the ITR Team. Team members, however, acting as independent reviewers, frequently assess the information from a perspective that differs significantly from that of the Mound Plant personnel. The report is based on information obtained and conditions observed during the March 1994 review interval. The ITR process and normal site work often initiate rapid, beneficial changes in understanding and organization immediately following the review. These changes frequently alter conditions observed during the review, but the report does not address changes subsequent to the review interval.

  1. The development of cold-water coral mounds along the Moroccan Atlantic and Mediterranean margins revealed by MeBo drillings

    NASA Astrophysics Data System (ADS)

    Hebbeln, Dierk; Wienberg, Claudia; Frank, Norbert

    2015-04-01

    Cold-water corals (CWC) mostly occur in intermediate water depths between 200 m and 1000 m and are capable of forming substantial seafloor structures, so-called coral carbonate mounds. These mounds can reach heights from a few meters up to >300 m and are composed of a mixture of CWC (and other shell) fragments and hemipelagic sediments, that both individually serve as distinct paleo-archives. IODP Leg 307 drilled through Challenger Mound at the Irish margin and revealed for the first time the full life history of a coral mound. However, although CWC occur almost worldwide, the 155 m long Challenger Mound record was for many years the only record from a coral mound exceeding 10 m in length. During expedition MSM36 with the German R/V MARIA S. MERIAN in spring 2014, several coral mounds along the Moroccan margin, both in the Atlantic Ocean and in the Mediterranean Sea, were drilled (actually: push-cored) by applying the Bremen Seafloor Drill Rig MeBo. The MeBo is a remotely controlled drilling system that is lowered from the vessel to the seafloor. Energy supply and video control are secured by an umbilical linking the MeBo to the vessel. The scientific foci of expedition MSM36 were to investigate (1) the long-term development of CWC mounds in both areas over the last several 100,000 years in relation to changes in the ambient environmental conditions in the respective intermediate waters, (2) the life time history of these mounds, and (3) the forcing factors for the initiation and decease of individual mounds. In both working areas, a total amount of 11 sites were successfully drilled with MeBo. Eight drillings were conducted at CWC mounds (on-mound sites) and 3 drillings in the direct vicinity of the mounds (off-mound sites) in order to obtain continuous paleoceanographic records. Drilling depths ranged between 17 m and 71 m with the latter corresponding to the maximum drilling depth of MeBo. The core recoveries varied between the sites and ranged between 47% and

  2. Minnesota 4-H Science of Agriculture Challenge: Infusing Agricultural Science and Engineering Concepts into 4-H Youth Development

    ERIC Educational Resources Information Center

    Rice, Joshua E.; Rugg, Bradley; Davis, Sharon

    2016-01-01

    Youth involved in 4-H projects have been engaged in science-related endeavors for years. Since 2006, 4-H has invested considerable resources in the advancement of science learning. The new Minnesota 4-H Science of Agriculture Challenge program challenges 4-H youth to work together to identify agriculture-related issues in their communities and to…

  3. Diversity Inclusion in 4-H Youth Programs: Examining the Perceptions among West Virginia 4-H Youth Professionals

    ERIC Educational Resources Information Center

    LaVergne, Douglas D.

    2013-01-01

    The study reported here sought to examine the perceptions of 4-H youth professionals towards diversity inclusion in 4-H youth programs. A majority of professionals positively reported that there are benefits for youth of color and youth with disabilities in 4-H youth programs. Respondents indicated that the lack of information about 4-H youth…

  4. Curtiss JN-4H Towing Model Wing

    NASA Technical Reports Server (NTRS)

    1921-01-01

    In 1919 the NACA Langley laboratory received its first three research aircraft which were Curtiss JN-4Hs borrowed from the US Army Air Service at Langley Field. One of the first research projects of the laboratory initiated that year was a flight investigation of the lift and drag characteristics of the JN-4H. One of the objectives of the flight tests was to obtain data for correlation with wind-tunnel test results measured at MIT and to aid in the derivation of techniques for extrapolation of model results to full-scale conditions. In a pioneering aeronautical effort in 1920, pressure orifices were installed in the horizontal tail of one of the Jennies and connected to glass manometers for pressure measurements that could be photographed in flight. The NACA also used the aircraft in some of the earliest experiments on maneuverability in 1921. In addition to serving as test subjects, the aircraft were used for measurements of aerodynamic behavior of aircraft components. In this photograph made in 1921, one of the JN- 4Hs is towing a model of an aircraft wing to obtain lift and drag information for comparison to tunnel results. All three Jenny aircraft departed Langley in 1923. Reference: 'Flying the Frontiers: NACA and NASA Experimental Aircraft' by Arthur Pearcy. Naval Institute Press, 1993. ISBN 1-55750-258-7

  5. Geology of Damon Mound Salt Dome, Texas

    SciTech Connect

    Collins, E.W.

    1989-01-01

    Geological investigation of the stratigraphy, cap-rock characteristics, deformation and growth history, and growth rate of a shallow coastal diapir. Damon Mound salt dome, located in Brazoria County, has salt less than 600 feet and cap rock less than 100 feet below the surface; a quarry over the dome provides excellent exposures of cap rock as well as overlying Oligocene to Pleistocene strata. These conditions make it ideal as a case study for other coastal diapirs that lack bedrock exposures. Such investigations are important because salt domes are currently being considered by chemical waste disposal companies as possible storage and disposal sites. In this book, the author reviews previous research, presents additional data on the subsurface and surface geology at Damon Mound, and evaluates Oligocene to post-Pleistocene diapir growth.

  6. Dynamic thermal structure of imported fire ant mounds.

    PubMed

    Vogt, James T; Wallet, Bradley; Coy, Steven

    2008-01-01

    A study was undertaken to characterize surface temperatures of mounds of imported fire ant, Solenopsis invicta Buren (Hymenoptera: Formicidae) and S. richteri Forel, and their hybrid, as it relates to sun position and shape of the mounds, to better understand factors that affect absorption of solar radiation by the nest mound and to test feasibility of using thermal infrared imagery to remotely sense mounds. Mean mound surface temperature peaked shortly after solar noon and exceeded mean surface temperature of the surrounding surface. Temperature range for mounds and their surroundings peaked near solar noon, and the temperature range of the mound surface exceeded that of the surrounding area. The temperature difference between mounds and their surroundings peaked around solar noon and ranged from about 2 to 10 degrees C. Quadratic trends relating temperature measurements to time of day (expressed as percentage of daylight hours from apparent sunrise to apparent sunset) explained 77 to 88% of the variation in the data. Mounds were asymmetrical, with the apex offset on average 81.5 +/- 1.2 mm to the north of the average center. South facing aspects were about 20% larger than north facing aspects. Mound surface aspect and slope affected surface temperature; this affect was greatly influenced by time of day. Thermal infrared imagery was used to illustrate the effect of mound shape on surface temperature. These results indicate that the temperature differences between mounds and their surroundings are sufficient for detection using thermal infrared remote sensing, and predictable temporal changes in surface temperature may be useful for classifying mounds in images.

  7. Upper Carboniferous reef mounds and climate change

    SciTech Connect

    West, R.R.; Archer, A.W. )

    1992-01-01

    Tetractinomorph demosponges (chaetetids) are a minor component of extant tropical reefs, but they were the major framebuilder of reef mounds during the Westphalian (Carboniferous). These chaetetids were confined to tropical latitudes during the Carboniferous, reached an abundance peak in the Westphalian, and then declined suddenly until the Upper Triassic. After their decline, red and green algae became the dominant reef builders of the Stephanian. The marked decline of chaetetids corresponds with the disappearance, and/or decline of other marine benthic invertebrates, as well as some terrestrial plants and is the basis for the biostratigraphic boundary between the Westphalian and Stephanian (Desmoinesian and Missourian). This biostratigraphic boundary coincides with a minor extinction event and a major'' climatic change. The Westphalian climate was wetter than that of the Stephanian, and in the midcontinent this change is recorded by a gradual decline in coals and siliciclastic lithologies and a corresponding increase in carbonate lithologies. A rise in water temperature might be expected in a drier tropical climate, and if extant chaetetids are any clue, elevated water temperature may have been detrimental. Extant chaetetids are associated with tropical coral reefs that are confined to a narrow temperature range. It is not unreasonable to suggest that elevated seawater temperatures were responsible, in part, for the disappearance of chaetetid reef mounds. Red and green algae, presumably more tolerate of higher water temperatures, became the major framebuilders of reef mounds in the Stephanian. Thus, the demise of chaetetid reef mounds, and other organisms at the end of the Westphalian, may be the result of global warming.

  8. Troubleshooting guide for Mound calorimeter systems

    SciTech Connect

    Breakall, K.L.; Duff, M.F.; Rodenburg, W.W.

    1988-06-29

    This report is to be used as a tool for troubleshooting Mound calorimeter systems. It describes in simple language the equilibration, prediction, and servo-control modes of operation. A problem-cause-action table provides suggestions and, in some cases, directs personnel to one of six troubleshooting flow charts included in the report. Using the flow charts, laboratory personnel should be able to rcognize and troubleshoot most problems that occur. 4 figs., 1 tab.

  9. EG G Mound Applied Technologies payroll system

    SciTech Connect

    Not Available

    1992-02-07

    EG G Mound Applied Technologies, Inc., manages and operates the Mound Facility, Miamisburg, Ohio, under a cost-plus-award-fee contract administered by the Department of Energy's Albuquerque Field Office. The contractor's Payroll Department is responsible for prompt payment in the proper amount to all persons entitled to be paid, in compliance with applicable laws, regulations, and legal decisions. The objective was to determine whether controls were in place to avoid erroneous payroll payments. EG G Mound Applied Technologies, Inc., did not have all the internal controls required by General Accounting Office Title 6, Pay, Leave, and Allowances.'' Specifically, they did not have computerized edits, separation of duties and responsibilities, and restricted access to payroll data files. This condition occurred because its managers were not aware of Title 6 requirements. As a result, the contractor could not assure the Department of Energy that payroll costs were processes accurately; and fraud, waste, or abuse of Department of Energy funds could go undetected. Our sample of 212 payroll transactions from a population of 66,000 in FY 1991 disclosed only two minor processing errors and no instances of fraud, waste or abuse.

  10. The Big E (Energy). 4-H Energy Project. 4-H Member's E-Book, Unit 1.

    ERIC Educational Resources Information Center

    Caldwell, William; And Others

    This activity and record book is designed for unit 1 (ages 9-11) of the Nebraska 4-H Energy Project. In this project, members are required to: (1) use energy wisely by closing doors and turning off lights; (2) inspecting homes for energy use at least once; (3) judging the best use of lighting in a home; (4) sharing ideas about energy use in a…

  11. CPR: Purposeful Action. Putting New Life into 4-H.

    ERIC Educational Resources Information Center

    Jones, Deborah A.; Smith, William C.

    1988-01-01

    In Ohio, 4-H professionals found that it is necessary to conduct market research to have an effective program. Cardiopulmonary resuscitation (CPR) training has been successful in strengthening the 4-H position in the marketplace. (JOW)

  12. Cartografical And Geodetical Aspects Of The Krakus Mound In Cracow

    NASA Astrophysics Data System (ADS)

    Banasik, Piotr

    2015-12-01

    In this work the fate of the Krakus Mound, the oldest of all existing Krakow's mounds, has been presented. The work was carried out based on selected iconographic, cartographic and geodetic documents. Using as an example old views, panoramas of the city and maps, various functions that the Krakus Mound was fulfilling over its long history were shown. An attempt was made to document the military significance of this mound and the surrounding hills. The particular astro-geodetic importance of the Krakus Mound on the scale of the city and southern Poland region was widely discussed. The Krakus Mound also inscribed itself in the history of the use of GPS technology as well as research on the local determination of the geoid in the area of Krakow.

  13. Hamsters?! What Does 4-H Stand for, Anyway?

    ERIC Educational Resources Information Center

    Grundeen, Brenda

    This paper briefly traces the history of 4-H youth development programs, explains what youth development is, and shows how the experiential learning model is used in 4-H. Begun over 75 years ago as a means of extending the learning of the land-grant university to rural youth, 4-H is part of the Cooperative Extension Service. The curriculum…

  14. The 4-H Club Meeting: An Essential Youth Development Strategy

    ERIC Educational Resources Information Center

    Cassels, Alicia; Post, Liz; Nestor, Patrick I.

    2015-01-01

    The club meeting has served as a key delivery method for 4-H programming across the United States throughout its history. A survey of WV 4-H community club members reinforces the body of evidence that the 4-H club meeting is an effective vehicle for delivering positive youth learning opportunities within the umbrella of the Essential Elements of…

  15. Using Digital Classrooms to Conduct 4-H Club Meetings

    ERIC Educational Resources Information Center

    West, Patricia; Fuhrman, Nicholas E.; Morgan, A. Christian; Duncan, Dennis W.

    2012-01-01

    Using computer technology and digital classrooms to conduct 4-H Club meetings is an efficient way to continue delivering quality 4-H programming during times of limited resources and staff. Nineteen Junior and Senior 4-H'ers participated in seven digital classroom workshops using the Wimba Classroom application. These digital classroom…

  16. Factors Affecting Teen Involvement in Pennsylvania 4-H Programming

    ERIC Educational Resources Information Center

    Gill, Bart E.; Ewing, John C.; Bruce, Jacklyn A.

    2010-01-01

    The study reported here determined the factors that affect teen involvement in 4-H programming. The design of the study was descriptive and correlational in nature. Using a purposive sampling procedure, a survey questionnaire was distributed to all (N=214) 4-H members attending the 4-H State Leadership Conference. The major findings of the study…

  17. A lone biodetrital mound in the Chesterian (Carboniferous) of Alabama?

    USGS Publications Warehouse

    Kopaska-Merkel, D. C.; Haywick, D.W.

    2001-01-01

    A carbonate mound in the Chesterian Bangor Limestone of Lawrence County, Alabama, consists chiefly of packstone and grainstone dominated by echinoderm ossicles and fragments of fenestrate bryozoans. In-situ colonies of the rugose coral Caninia flaccida comprise about 8% of the mound by volume. The exposed portion of the mound is approximately 25 m wide, 1.6 m thick at the thickest point and roughly circular in plan. The mound developed on top of a shallow ooid shoal that had been cemented and stabilised during an earlier episode of sub-aerial exposure. Subsequent flooding of the exposed shoal surface permitted establishment of the mound biota. Lateral and vertical facies relationships suggest that the mound possessed about 45 cm of synoptic relief when fully developed. Rugose corals, fenestrate and ramose bryozoans, stalked echinoderms, and sessile soft-bodied organisms encrusted by foraminifera colonised the shoal, forming a mound. Baffling resulted in deposition of mixed-fossil packstone containing locally derived debris and coated grains from the surrounding sea floor. Strong currents within the mound are indicated by preferred orientation of corals and by coarse, commonly cross-stratified grainstone in channels between neighboring coral colonies. Corals are most abundant on the windward side of the mound, where they account for about 13% of the mound compared to 6- 10% in the central part of the mound, and 2-4% on the leeward flank. Biodetrital mounds such as the one described here are uncommon in upper Paleozoic strata and previously unknown in the Bangor Limestone. Of 10 carbonate buildups we examined in the Bangor in Alabama and Tennessee, only one is a biodetrital mound. Two are rugose coral-microbial reefs, one is a coral biostrome, and six are dominated by microbialite. The Bangor shelf, previously interpreted as sedimentologically simple, appears to contain many small mounds of quite varied characteristics. Also, the discovery of a biodetrital mound in

  18. The Goodlett-Denny mound: a glimpse at 45 years of Pennsylvania treethrow mound evolution with implications for mass wasting

    NASA Astrophysics Data System (ADS)

    Small, Thomas W.

    1997-03-01

    A rootplate/mound formed by the uprooting of a black cherry tree ( Prunus serotina) in Potter County, Pennsylvania, was photographed in 1950 near the time of formation and again in 1952 and 1963 by J.C. Goodlett and C.S. Denny. The mound was located and photographed by the author in 1989 with the aid of background trees with identifying peculiarities and using the earlier consistent perspectives. Between 1950 and 1963 most of the rootmass had decomposed, leaving a mound with an estimated volume of 5.28 m 3 in 1963. By 1989 the mound had lost 60% of its 1963 height and its volume had diminished to 2.09 m 3. Mean annual erosion on the mound from 1989 to 1995 was much less than during the 1963-1989 period indicating a diminishing sediment contribution to the forest floor commensurate with lowering of the mound surface.

  19. Asphalt mounds and associated biota on the Angolan margin

    NASA Astrophysics Data System (ADS)

    Jones, Daniel O. B.; Walls, Anne; Clare, Michael; Fiske, Mike S.; Weiland, Richard J.; O'Brien, Robert; Touzel, Daniel F.

    2014-12-01

    Release of hydrocarbons from sediments is important in increasing habitat heterogeneity on deep ocean margins. Heterogeneity arises from variation in abiotic and biotic conditions, including changes in substratum, geochemistry, fluid flow, biological communities and ecological interactions. The seepage of heavy hydrocarbons to the seafloor is less well studied than most other cold seep systems and may lead to the formation of asphalt mounds. These have been described from several regions, particularly the Gulf of Mexico. Here, we describe the structure, potential formation and biology of a large asphalt mound province in Block 31SE Angola. A total of 2254 distinct mound features was identified by side-scan sonar, covering a total area of 3.7 km2 of seafloor. The asphalt mounds took a number of forms from small (<0.5 m diameter; 13% observations) mounds to large extensive (<50 m diameter) structures. Some of the observed mounds were associated with authigenic carbonate and active seepage (living chemosynthetic fauna present in addition to the asphalt). The asphalt mounds are seabed accumulations of heavy hydrocarbons formed from subsurface migration and fractionation of reservoir hydrocarbons primarily through a network of faults. In Angola these processes are controlled by subsurface movement of salt structures. The asphalt mounds were typically densely covered with epifauna (74.5% of mounds imaged had visible epifauna) although individual mounds varied considerably in epifaunal coverage. Of the 49 non-chemosynthetic megafaunal taxa observed, 19 taxa were only found on hard substrata (including asphalt mounds), 2 fish species inhabited the asphalt mounds preferentially and 27 taxa were apparently normal soft-sediment fauna. Antipatharians (3.6±2.3% s.e.) and poriferans (2.6±1.9% s.e.) accounted for the highest mean percentage of the observed cover, with actinarians (0.9±0.4% s.e.) and alcyonaceans (0.4±0.2% s.e.) covering smaller proportions of the area

  20. Why 4-H Members Leave: A Study of Discontinuance through Both Current 4-H Members and Former Members

    ERIC Educational Resources Information Center

    Chilek, Kevin Dwayne

    2012-01-01

    4-H members quit. It is part of every 4-H program, and according to the research, it is even part of growing up. If only we knew why they quit, we could possibly do something about it. To date, the reasons youth join 4-H have been more thoroughly researched than the reasons they quit. This study explores why youth choose to discontinue membership…

  1. Environmental assessment for Mound Plant decontamination and decommissioning projects, Mound Plant, Miamisburg, Ohio

    SciTech Connect

    1995-05-01

    The U.S. Department of Energy (DOE) has prepared an Environmental Assessment (EA) for seven decontamination and decommissioning (D&D) projects at the Mound Plant in Miamisburg, Ohio, that have not been previously addressed in the Final Environmental Impact Statement for the Mound Facility (June 1979). Based on the information presented in the EA, the DOE has determined that the proposed action is not a major Federal action significantly affecting the quality of the human environment within the meaning of the National Environmental Policy Act (NEPA) of 1969. Therefore, the preparation of an Environmental Impact Statement (EIS) is not required and the Department is issuing this Finding of No Significant Impact (FONSI).

  2. The Oneida County 4-H Conservation Field Days Conflict.

    ERIC Educational Resources Information Center

    Brown, Stephen C.; Vonhof, Sarah; Kelley, Alicia

    2003-01-01

    Examines the various perspectives held by the three major organizations involved (an environmental citizens group, a local sportsmen's club, and the cooperative extension service) regarding a conflict over a 4-H program involving hunting and wildlife management. Discusses why the 4-H program's attempt to build consensus among the organizations was…

  3. Embracing Scientific and Engineering Practices in 4-H

    ERIC Educational Resources Information Center

    Worker, Steven M.

    2013-01-01

    The 4-H Science Initiative has renewed efforts to strengthen 4-H programmatic and evaluation efforts in science and engineering education. A fundamental component of this initiative is to provide opportunities to youth to aid in their development of science process skills; however, emerging research stresses the importance of engaging youth in…

  4. Council of Presidents: A Multifaceted Idea for 4-H

    ERIC Educational Resources Information Center

    Torretta, Alayne

    2015-01-01

    Communication between 4-H professionals and the youth they work with is an important part of a successful 4-H program. By creating a Council of Presidents comprised of officers of all the clubs in your county, you can increase communication while assuring your program addresses all four essential elements. The Council is also as a vehicle for…

  5. 4-H Participation and Science Interest in Youth

    ERIC Educational Resources Information Center

    Heck, Katherine; Carlos, Ramona M.; Barnett, Cynthia; Smith, Martin H.

    2012-01-01

    The study reported here investigated the impacts of participation in 4-H on young people's interest and participation in science. Survey data were collected from relatively large and ethnically diverse samples of elementary and high school-aged students in California. Results indicated that although elementary-grade 4-H members are not more…

  6. Geochemical Arrays at Woolsey Mound Seafloor Observatory

    NASA Astrophysics Data System (ADS)

    Sleeper, K.; Wilson, R. M.; Chanton, J.; Lapham, L.; Farr, N.; Camilli, R.; Martens, C. S.; Pontbriand, C.

    2011-12-01

    A suite of geochemical monitoring arrays has been developed for the Woolsey Mound Seafloor Observatory in the northern Gulf of Mexico to evaluate the oceanographic and tectonic forcing factors on the formation and stability of gas hydrates. These arrays are designed to collect sustained, time-series data of chemical concentrations, gradients and fluxes from the subsurface to the seafloor and into the near bottom water column. A Pore Fluid Array provides time-series measurements of methane, sulfate and salinity in subsurface pore waters to evaluate microbial activity, hydrate formation and/or hydrate dissociation. A Chimney Sampler Array collects in situ chemical and physical readings at the benthic boundary. The array is designed around a vertical cylinder with a known volume and washout rate for measuring chemical gradients and flux at the seafloor. The Benthic Boundary Layer Array extends into the water column with a package of sensors in a node close to the seafloor and a similar node 20 m above the seafloor to evaluate upward, downward and transversely advecting fluids. The three arrays can be used in concert to evaluate a release of methane by the dissociation of gas hydrates: the Pore Fluid Array identifies the breakdown of gas hydrates in the subsurface, the Chimney Array determines the rate of flux at the seafloor and the Benthic Boundary Layer Array evaluates the fate of the release in the water column. Combining the data from the geochemical arrays with output from the geophysical arrays provides key information to evaluate the specific and relative importance of tectonic and oceanographic triggers for hydrate dissociation. New probes and deployment platforms have been developed for the installation and maintenance of the arrays and new systems are in place and under development for the recovery of the data. Generally, the complete array or its components have to be recovered to download the data. However, this summer 2011, a new optic modem system was

  7. Biotic Origin for Mima Mounds Supported by Numerical Model

    NASA Astrophysics Data System (ADS)

    Gabet, E. J.; Perron, J.; Johnson, D. L.

    2013-12-01

    Mima mounds are ~1-m-high hillocks found on every continent except Antarctica. Despite often numbering in the millions within a single field, their origin has been a mystery, with proposed explanations ranging from glacial processes to seismic shaking. One hypothesis proposes that mounds in North America are built by burrowing mammals to provide refuge from seasonally saturated soils. We test this hypothesis with a numerical model, parameterized with measurements of soil transport by gophers from a California mound field, that couples animal behavior with geomorphic processes. The model successfully simulates the development of the mounds, as well as key details such as the creation of vernal pools, small intermound basins that provide habitat for endemic species. Furthermore, we demonstrate that the spatial structure of the modeled mound fields is similar to actual mound fields and provides an example of self-organized topographic features. We conclude that, scaled by body mass, Mima mounds are the largest structures built by non-human mammals, and may provide a rare example of an evolutionary coupling between landforms and the organisms that create them.

  8. Biotic origin for Mima mounds supported by numerical modeling

    NASA Astrophysics Data System (ADS)

    Gabet, Emmanuel J.; Perron, J. Taylor; Johnson, Donald L.

    2014-02-01

    Mima mounds are ~ 1-m-high hillocks found on every continent except Antarctica. Despite often numbering in the millions within a single field, their origin has been a mystery, with proposed explanations ranging from glacial processes to seismic shaking. One hypothesis proposes that mounds in North America are built by burrowing mammals to provide refuge from seasonally saturated soils. We test this hypothesis with a numerical model, parameterized with measurements of soil transport by gophers from a California mound field, that couples animal behavior with geomorphic processes. The model successfully simulates the development of the mounds as well as key details such as the creation of vernal pools, small intermound basins that provide habitat for endemic species. Furthermore, we demonstrate that the spatial structure of the modeled mound fields is similar to actual mound fields and provides an example of self-organized topographic features. We conclude that, scaled by body mass, Mima mounds are the largest structures built by nonhuman mammals and may provide a rare example of an evolutionary coupling between landforms and the organisms that create them.

  9. Late Mississippian lime mud mounds, Pitkin Formation, northern Arkansas

    SciTech Connect

    Manger, W.L.; Ar, V.P.; Webb, G.E.

    1984-04-01

    Carbonates deposited under shallow, open shelf conditions during the Late Mississippian in northern Arkansas exhibit numerous discrete to coalescing lime mud mounds up to 20 m (65 ft) high and tens of meters in diameter. The mounds are composed of a carbonate mud core, typically with fenestrate texture, entrapped by a loosely organized framework dominated by cystoporate bryozoans and rugose corals in the lower part, and by blue-green algae and cryptostomous bryozoans in the upper part. Disarticulated crinozoan detritus is common throughout the core, suggesting that these organisms also contributed to entrapment of lime mud. During deposition, the mud core was indurated enough to support and preserve vertical burrows. Also, rubble of core mudstone is found on the flanks of some mounds, suggesting some erosion. Intermound lithology is a shoaling-upward sequence dominated by oolitic and bioclastic grainstones and packstones. Shale is also present in minor amounts. The Pitkin mounds, interbedded with these intermound sequences, developed contemporaneously with them. Depositional relief was probably less than 3 m (10 ft). The mounds expanded laterally during periods of quieter water; their growth was impeded during times of higher energy. Contacts of the mound and intermound lithologic characteristics are sharp, truncating surfaces. Mound deposition ended with the onset of high energy conditions throughout the region.

  10. Stabilization of 4H hexagonal phase in gold nanoribbons

    PubMed Central

    Fan, Zhanxi; Bosman, Michel; Huang, Xiao; Huang, Ding; Yu, Yi; Ong, Khuong P.; Akimov, Yuriy A.; Wu, Lin; Li, Bing; Wu, Jumiati; Huang, Ying; Liu, Qing; Eng Png, Ching; Lip Gan, Chee; Yang, Peidong; Zhang, Hua

    2015-01-01

    Gold, silver, platinum and palladium typically crystallize with the face-centred cubic structure. Here we report the high-yield solution synthesis of gold nanoribbons in the 4H hexagonal polytype, a previously unreported metastable phase of gold. These gold nanoribbons undergo a phase transition from the original 4H hexagonal to face-centred cubic structure on ligand exchange under ambient conditions. Using monochromated electron energy-loss spectroscopy, the strong infrared plasmon absorption of single 4H gold nanoribbons is observed. Furthermore, the 4H hexagonal phases of silver, palladium and platinum can be readily stabilized through direct epitaxial growth of these metals on the 4H gold nanoribbon surface. Our findings may open up new strategies for the crystal phase-controlled synthesis of advanced noble metal nanomaterials. PMID:26216712

  11. Integrated study of Mississippian Lodgepole Waulsortian Mounds, Williston Basin, USA

    SciTech Connect

    Kupecz, J.A.; Arestad, J.F.; Blott, J. E.

    1996-06-01

    Waulsortian-type carbonate buildups in the Mississippian Lodgepole Formation, Williston Basin, constitute prolific oil reservoirs. Since the initial discovery in 1993, five fields have been discovered: Dickinson Field (Lodgepole pool); Eland Field; Duck Creek Field, Versippi Field; and Hiline Field. Cumulative production (October, 1995) is 2.32 million barrels of oil and 1.34 BCF gas, with only 69,000 barrels of water. Oil gravity ranges from 41.4 to 45.3 API. Both subsurface cores from these fields as well as outcrop (Bridget Range, Big Snowy and Little Belt Mountains, Montana) are composed of facies representing deposition in mound, reworked mound, distal reworked mound, proximal flank, distal flank, and intermound settings. Porosity values within the mound and reworked mound facies are up to 15%; permeability values (in places fracture-enhanced) are up to tens of Darcies. Geometries of the mounds are variable. Mound thicknesses in the subsurface range from approximately 130-325 feet (40-100 meters); in outcrop thicknesses range from less than 30 ft (9 m) to over 250 ft (76 m). Subsurface areal dimensions range from approximately 0.5 x 1.0 mi (0.8 x 1.6 km) to 3.5 x 5.5 mi (5.6 x 8.8 km). Integration of seismic data with core and well-log models sheds light on the exploration for Lodgepole mounds. Seismic modeling of productive mounds in the Dickinson and Eland fields identifies characteristics useful for exploration, such as local thickening of the Lodgepole to Three Forks interval. These observations are confirmed in reprocessed seismic data across Eland field and on regional seismic data. Importantly, amplitude versus offset modeling identifies problems with directly detecting and identifying porosity within these features with amplitude analyses. In contrast, multicomponent seismic data has great potential for imaging these features and quantifying porous zones within them.

  12. Fractal-mound growth of pentacene thin films

    NASA Astrophysics Data System (ADS)

    Zorba, Serkan; Shapir, Yonathan; Gao, Yongli

    2006-12-01

    The growth mechanism of pentacene film formation on SiO2 substrate was investigated with a combination of atomic force microscopy measurements and numerical modeling. In addition to the diffusion-limited aggregation (DLA) that has already been shown to govern the growth of the ordered pentacene thin films, it is shown here that the Schwoebel barrier effect steps in and disrupts the desired epitaxial growth for the subsequent layers, leading to mound growth. The terraces of the growing mounds have a fractal dimension of 1.6, indicating a lateral DLA shape. This growth morphology thus combines horizontal DLA-like growth with vertical mound growth.

  13. Biodiversity and ecological composition of macrobenthos on cold-water coral mounds and adjacent off-mound habitat in the bathyal Porcupine Seabight, NE Atlantic

    NASA Astrophysics Data System (ADS)

    Henry, Lea-Anne; Roberts, J. Murray

    2007-04-01

    The cold-water scleractinian corals Lophelia pertusa and Madrepora oculata form mound structures on the continental shelf and slope in the NE Atlantic. This study is the first to compare the taxonomic biodiversity and ecological composition of the macrobenthos between on- and off-mound habitats. Seven box cores from the summits of three mounds and four cores from an adjacent off-mound area in the Belgica Mound Province in the Porcupine Seabight yielded 349 species, including 10 undescribed species. On-mound habitat was three times more speciose, and was richer with higher evenness and significantly greater Shannon's diversity than off-mound. Species composition differed significantly between habitats and the four best discriminating species were Pliobothrus symmetricus (more frequent off-mound), Crisia nov. sp, Aphrocallistes bocagei and Lophelia pertusa (all more frequent on-mound). Filter/suspension feeders were significantly more abundant on-mound, while deposit feeders were significantly more abundant off-mound. Species composition did not significantly differ between mounds, but similarity within replicates decreased from Galway MoundMound. We propose that, despite having greater vertical habitat heterogeneity that supports higher biodiversity, coral mounds have a characteristic "reef fauna" linked to species' biology that contrasts with the higher horizontal habitat heterogeneity conferred by the action of deposit feeders and a varied seabed sedimentary facies off-mound. Standardisation of equipment and restriction of analyses to higher taxonomic levels would facilitate prospective comparative analyses of cold-water coral biodiversity across larger spatio-temporal scales.

  14. Evolution of Mound Morphology in Reversible Homoepitaxy on Cu(100)

    SciTech Connect

    Zuo, J.; Wendelken, J.

    1997-04-01

    Evolution of mound morphology in reversible homoepitaxy on Cu(100) was studied via spot-profile-analysis (SPA) LEED and scanning tunneling microscopy. The mound separation shows coarsening vs growth time with L(t){approximately}t{sup 1/4}, in support of theory based on capillarity between mounds. The growth ultimately reaches a steady state characterized by a selected mound angle of {approximately}5.6{degree}. We suggest that this results from a downhill current driven by step edge line tension in balance with an uphill current due to the Schwoebel barrier effect. Also, we have clarified the interpretation for the evolution of the SPA-LEED profile from a ring structure to a single time-invariant peak. {copyright} {ital 1997} {ital The American Physical Society}

  15. 2. CONCRETE PADDING AREA BETWEEN BERM MOUNDS, LOOKING NORTH FROM ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    2. CONCRETE PADDING AREA BETWEEN BERM MOUNDS, LOOKING NORTH FROM TOP OF BERM. - NIKE Missile Base C-84, Acid Fueling Station, North of Launch Area Entrance Drive, eastern central portion of base, Barrington, Cook County, IL

  16. Possible Frost Mounds in an Ancient Martian Lake Bed

    NASA Astrophysics Data System (ADS)

    Cabrol, Nathalie A.; Grin, Edmond A.; Pollard, Wayne H.

    2000-05-01

    Circular to elongated mounds are observed in Gusev crater in the Aeolis subquadrangle of Mars. They are arranged in a large cluster and show different stages of evolution, from fresh to scar structures. Their morphology and morphometric ratios are comparable to those of terrestrial frost mounds. This study shows how the paleolacustrine environment of the Ma'adim Vallis/Gusev crater hydrogeologic system may have provided a suitable environment for the formation of frost mounds. Alternate hypotheses of formation including volcanism, fluvial erosion, and eolian erosion are discussed. Other features such as heavings, curvilinear troughs, hills, ridges, and depressions support the idea of a sediment/ice interaction. The typology of the mounds and plausible mechanisms for their formation are proposed. Their presence could support the model of a massive water body in Gusev during the Amazonian and provide indicators of paleoenvironmental conditions at the time of their formation.

  17. VIEW LOOKING NORTHEAST AT EARTH MOUND. NOTE THE RECTANGULAR OPENINGS ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    VIEW LOOKING NORTHEAST AT EARTH MOUND. NOTE THE RECTANGULAR OPENINGS USED FOR OBSERVATION EQUIPMENT AND PERISCOPE TOPS. - Marshall Space Flight Center, Redstone Rocket (Missile) Test Stand, Dodd Road, Huntsville, Madison County, AL

  18. 1. Perspective view southwest of filtration bed with earth mounded ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    1. Perspective view southwest of filtration bed with earth mounded over facility. Armory Street appears in the foreground. - Lake Whitney Water Filtration Plant, Filtration Plant, South side of Armory Street between Edgehill Road & Whitney Avenue, Hamden, New Haven County, CT

  19. Simulation of Groundwater Mounding Beneath Hypothetical Stormwater Infiltration Basins

    USGS Publications Warehouse

    Carleton, Glen B.

    2010-01-01

    Groundwater mounding occurs beneath stormwater management structures designed to infiltrate stormwater runoff. Concentrating recharge in a small area can cause groundwater mounding that affects the basements of nearby homes and other structures. Methods for quantitatively predicting the height and extent of groundwater mounding beneath and near stormwater Finite-difference groundwater-flow simulations of infiltration from hypothetical stormwater infiltration structures (which are typically constructed as basins or dry wells) were done for 10-acre and 1-acre developments. Aquifer and stormwater-runoff characteristics in the model were changed to determine which factors are most likely to have the greatest effect on simulating the maximum height and maximum extent of groundwater mounding. Aquifer characteristics that were changed include soil permeability, aquifer thickness, and specific yield. Stormwater-runoff variables that were changed include magnitude of design storm, percentage of impervious area, infiltration-structure depth (maximum depth of standing water), and infiltration-basin shape. Values used for all variables are representative of typical physical conditions and stormwater management designs in New Jersey but do not include all possible values. Results are considered to be a representative, but not all-inclusive, subset of likely results. Maximum heights of simulated groundwater mounds beneath stormwater infiltration structures are the most sensitive to (show the greatest change with changes to) soil permeability. The maximum height of the groundwater mound is higher when values of soil permeability, aquifer thickness, or specific yield are decreased or when basin depth is increased or the basin shape is square (and values of other variables are held constant). Changing soil permeability, aquifer thickness, specific yield, infiltration-structure depth, or infiltration-structure shape does not change the volume of water infiltrated, it changes the

  20. Sodium diffusion in 4H-SiC

    SciTech Connect

    Linnarsson, M. K. Hallén, A.

    2014-09-01

    Sodium diffusion has been studied in p-type 4H-SiC. Heat treatments have been performed from 1200 °C to 1800 °C for 1 min to 4 h. Secondary ion mass spectrometry has been used to measure the sodium distribution. We show that sodium has a considerable mobility at 1200 °C in p-type 4H-SiC. On the other hand for sodium atoms trapped at suitable sites the mobility is limited up to 1800 °C. Trap limited diffusion kinetics is suggested and an effective diffusivity has been extracted with an activation energy of 4 eV for sodium diffusion in p-type 4H-SiC.

  1. Environmental assessment for commercialization of the Mound Plant

    SciTech Connect

    Not Available

    1994-10-26

    In November 1993 US DOE decided to phase out operations at the Mound Plant in Miamisburg, Ohio, with the goal of releasing the site for commercial use. The broad concept is to transform the plant into an advanced manufacturing center with the main focus on commercializing products and other technology. DOE proposes to lease portions of the Mound Plant to commercial enterprises. This Environmental Impact statement has a finding of no significant impact in reference to such action.

  2. Properties of homoepitaxial 4H-SiC and characteristics of Ti/4H-SiC Schottky barrier diodes

    NASA Astrophysics Data System (ADS)

    Chen, G.; Li, Z. Y.; Bai, S.; Han, P.

    2008-02-01

    This paper describes the properties of the homoepitaxial 4H-SiC layer, the fabrication and electrical parameters of Ti/4H-SiC Schottky barrier diode (SBD). The 4H-SiC epitaxial layers, grown on the commercially available 8°off-oriented Si-face(0001) single-crystal 4H-SiC wafers, have been performed at 1550~1600°C by using the step controlled epitaxy with low pressure chemical vapor deposition. X-ray diffraction measurement result indicates the single crystal nature of the epilayer, and Raman spectrum shows the typical 4H-SiC feature peaks. When the off-oriented angle of substrate is 8°, the epitaxial growth perfectly replicates the substrate's polytype. High quality 4H-SiC epilayer has been generated on the 4H-SiC substrate. Ti/4H-SiC SBDs with blocking voltage 1kV have been made on an undoped epilayer with 12um in thick and 3×10 15cm -3 in carrier density. The ideality factor n=1.16 and the effective barrier height φ e=0.9V of the Ti/4H-SiC SBDs are measured with method of forward density-voltage (J-V). The diode rectification ratio of forward to reverse (defined at +/-1V) is over 10 7 at room temperature. By using B + implantation, an amorphous layer as the edge termination is formed. The SBDs have on-state current density of 200A/cm2 at a forward voltage drop of about 2V. The specific on-resistance for the rectifier is found to be as 6.6mΩ•cm2.

  3. Termite mounds harness diurnal temperature oscillations for ventilation

    PubMed Central

    King, Hunter; Ocko, Samuel; Mahadevan, L.

    2015-01-01

    Many species of millimetric fungus-harvesting termites collectively build uninhabited, massive mound structures enclosing a network of broad tunnels that protrude from the ground meters above their subterranean nests. It is widely accepted that the purpose of these mounds is to give the colony a controlled microclimate in which to raise fungus and brood by managing heat, humidity, and respiratory gas exchange. Although different hypotheses such as steady and fluctuating external wind and internal metabolic heating have been proposed for ventilating the mound, the absence of direct in situ measurement of internal air flows has precluded a definitive mechanism for this critical physiological function. By measuring diurnal variations in flow through the surface conduits of the mounds of the species Odontotermes obesus, we show that a simple combination of geometry, heterogeneous thermal mass, and porosity allows the mounds to use diurnal ambient temperature oscillations for ventilation. In particular, the thin outer flutelike conduits heat up rapidly during the day relative to the deeper chimneys, pushing air up the flutes and down the chimney in a closed convection cell, with the converse situation at night. These cyclic flows in the mound flush out CO2 from the nest and ventilate the colony, in an unusual example of deriving useful work from thermal oscillations. PMID:26316023

  4. Termite mounds harness diurnal temperature oscillations for ventilation.

    PubMed

    King, Hunter; Ocko, Samuel; Mahadevan, L

    2015-09-15

    Many species of millimetric fungus-harvesting termites collectively build uninhabited, massive mound structures enclosing a network of broad tunnels that protrude from the ground meters above their subterranean nests. It is widely accepted that the purpose of these mounds is to give the colony a controlled microclimate in which to raise fungus and brood by managing heat, humidity, and respiratory gas exchange. Although different hypotheses such as steady and fluctuating external wind and internal metabolic heating have been proposed for ventilating the mound, the absence of direct in situ measurement of internal air flows has precluded a definitive mechanism for this critical physiological function. By measuring diurnal variations in flow through the surface conduits of the mounds of the species Odontotermes obesus, we show that a simple combination of geometry, heterogeneous thermal mass, and porosity allows the mounds to use diurnal ambient temperature oscillations for ventilation. In particular, the thin outer flutelike conduits heat up rapidly during the day relative to the deeper chimneys, pushing air up the flutes and down the chimney in a closed convection cell, with the converse situation at night. These cyclic flows in the mound flush out CO2 from the nest and ventilate the colony, in an unusual example of deriving useful work from thermal oscillations.

  5. Termite mounds harness diurnal temperature oscillations for ventilation.

    PubMed

    King, Hunter; Ocko, Samuel; Mahadevan, L

    2015-09-15

    Many species of millimetric fungus-harvesting termites collectively build uninhabited, massive mound structures enclosing a network of broad tunnels that protrude from the ground meters above their subterranean nests. It is widely accepted that the purpose of these mounds is to give the colony a controlled microclimate in which to raise fungus and brood by managing heat, humidity, and respiratory gas exchange. Although different hypotheses such as steady and fluctuating external wind and internal metabolic heating have been proposed for ventilating the mound, the absence of direct in situ measurement of internal air flows has precluded a definitive mechanism for this critical physiological function. By measuring diurnal variations in flow through the surface conduits of the mounds of the species Odontotermes obesus, we show that a simple combination of geometry, heterogeneous thermal mass, and porosity allows the mounds to use diurnal ambient temperature oscillations for ventilation. In particular, the thin outer flutelike conduits heat up rapidly during the day relative to the deeper chimneys, pushing air up the flutes and down the chimney in a closed convection cell, with the converse situation at night. These cyclic flows in the mound flush out CO2 from the nest and ventilate the colony, in an unusual example of deriving useful work from thermal oscillations. PMID:26316023

  6. Food preferences and mound-building behaviour of the mound-building mice Mus spicilegus

    NASA Astrophysics Data System (ADS)

    Hölzl, Michaela; Krištofík, Ján; Darolová, Alžbeta; Hoi, Herbert

    2011-10-01

    Optimal foraging strategies and food choice are influenced by various factors, e.g. availability, size and caloric content of the food type and predation risk. However, food choice criteria may change when food is not eaten immediately but has to be carried to a storage site for later use. For example, handling time in terms of harvesting and transport time should be optimized, particularly when the risk of predation is high. Thus, it is not clear whether food selected by hoarding animals reflects their food preference due to intrinsic features of the food type, e.g. size, caloric or lipid content, or whether the food type selected is a compromise that also considers the handling time required for harvesting and transport. We investigate this question in relation to food hoarding behaviour in mound-building mice. In autumn, mound-building mice Mus spicilegus collect seeds and other plant material and cover it with soil. Such above-ground storage is quite unusual for rodents. Here, we investigated whether there is a relationship between the seed species preferred as building materials and those preferred for food. We conducted a seed preference test using three most collected weed species for mound building. Controlling factors like food availability or predation risk, mice prefer Setaria spp. as food, although Amaranthus spp. and Chenopodium spp. were preferentially harvested and stored. By including the availability of the three species, our experimental results were confirmed, namely, a clear preference for Setaria spp. Also, handling time and seed size revealed to influence plant choice.

  7. Hydrodynamic Conditions Influencing Cold-Water Coral Carbonate Mound Development (Challenger Mound, Porcupine Seabight, NE Atlantic): a Contribution to IODP Exp307

    NASA Astrophysics Data System (ADS)

    Thierens, M.; Odonnell, R.; Stuut, J.; Titschack, J.; Dorschel, B.; Wheeler, A. J.

    2007-12-01

    Cold-water coral carbonate mounds are complex geo-biological systems, originating from the interplay of hydrodynamic, sedimentological and biological factors. As changes in hydrodynamic and sedimentary regime are assumed to be amongst the main controls on mound evolution, reconstruction of the hydrodynamic and palaeoclimatic microenvironment on-mound, compared to the background environmental conditions (as seen off- mound), contributes to the fundamental understanding of these intriguing features and the development of a cold- water coral carbonate mound development model. Challenger Mound, one of the large cold-water coral carbonate mounds along the eastern Porcupine Seabight continental margin (NE Atlantic, SW off Ireland), was successfully drilled during IODP Expedition 307, providing the first complete recovery of a continuous sedimentary sequence through a carbonate mound. High-resolution particle size analysis of the terrigenous sediment component is used as primary proxy for reconstructing the hydrodynamic conditions during mound development. First results indicate repeated shifts in hydrodynamic conditions during sediment deposition on Challenger Mound, from lower-energetic conditions to higher-energetic environments and visa versa, which might reflect environmental variation over interglacial-glacial timescales throughout the whole mound development period. In conjunction with other available data, this dataset provides insight in local current regimes and sediment dynamics, the specific role of cold-water corals in these complex geo-biological systems and the differentiation of different sediment contributors to the coral mound system and its surroundings.

  8. Isomer Energy Differences for the C4H3 and C4H5 Isomers UsingDiffusion Monte Carlo

    SciTech Connect

    Domin, D.; Lester Jr., W.A.; Whitesides, R.; Frenklach, M.

    2007-12-01

    A new diffusion Monte Carlo study is performed on the isomers of C{sub 4}H{sub 3} and C{sub 4}H{sub 5} emulating the methodology of a previous study [Int. J. Chem. Kinetics 33, 808 (2001)]. Using the same trial wave function form of the previous study, substantially different isomerization energies were found owing to the use of larger walker populations in the present work. The energy differences between the E and I isomers of C{sub 4}H{sub 3} were found to be 10.5 {+-} 0.5 kcal/mol and for C{sub 4}H{sub 5}, 9.7 {+-} 0.6 kcal/mol. These results are in reasonable accord with recent MRCI and CCSD(T) findings.

  9. Electronic spectra of C4H3Cl+ isomers

    NASA Astrophysics Data System (ADS)

    Chakrabarty, S.; Rudnev, V.; Fulara, J.; Dietsche, R.; Nagy, A.; Garkusha, I.; Mazzotti, F. J.; Rice, C. A.; Maier, J. P.

    2012-12-01

    Two experimental methods were applied to identify the structure and electronic transitions of C4H3Cl+ isomers. The first is a direct absorption technique where mass-selected ions are embedded in 6 K neon matrices using a mass-selected ion beam and absorption spectra of different C4H3Cl+ isomers were thus observed. The second is a gas phase method on ions which have been collisional cooled with cryogenic helium inside of a 22-pole ion trap. The c-type (1)2 A‧ ← X 2 A″ electronic transition of a C4H3Cl+ isomer could then be measured by a one-colour, two-photon technique at 20 and 50 K in the gas phase. The two sets of data, complemented by calculated excitation energies, allowed the assignment of particular isomers. Rotational structure in the gas phase spectra was resolved for C4H3 35Cl+ and C4H3 37Cl+ isomers of cis-1-chlorobutenynylium. The analysis leads to the spectroscopic constants: T 00 = 19 184.680(5), ? , ? , ? , ? , ? and ? (all in cm-1).

  10. On the Ionization Energies of C4H3 Isomers

    SciTech Connect

    Kaiser, Ralf I.; Mebel, Alexander; Kostko, Oleg; Ahmed, Musahid

    2009-09-16

    We have conducted a combined experimental and theoretical study on the formation of distinct isomers of resonantly stabilized free radicals, C4H3, which are important intermediates in the formation of polycyclic aromatic hydrocarbons in combustion flames and possibly in the interstellar medium. Our study utilized laser ablation of graphite in combination with seeding the ablated species in neat methylacetylene gas which also acted as a reagent. Photoionization efficiency (PIE) curves were recorded of the C4H3 isomers at the Advanced Light Source from 8.0 to 10.3 eV. The experimental PIE curve was compared with theoretical ones suggesting the formation of four C4H3 radicals: two acyclic structures i-C4H3 [1] and E/Z-n-C4H3 [2E/2Z]and two cyclic isomers 3 and 4. These molecules are likely formed via an initial addition of ground state carbon atoms to the carbon-carbon triple bond of the methylacetylene molecule followed by isomerization via hydrogen migrations and ring opening and emission of atomic hydrogen from these intermediates.

  11. Controls on mound formation and effects of fluid ascent on the gas hydrate system of mound structures offshore Costa Rica

    NASA Astrophysics Data System (ADS)

    Planert, L.; Klaeschen, D.; Berndt, C.; Hensen, C.; Brueckmann, W.

    2010-12-01

    Our analysis of 2D MCS seismic data from the Middle America margin provides an insight into the buildup and formation mechanisms of mound structures and the effects of fluid ascent on the gas hydrate system observed on the continental slope offshore Costa Rica. Our targets, Mounds 11&12, are the sites of IODP drilling proposal 633-Full2, which aims to enhance the general understanding of complex forearc dewatering processes of the erosive subduction system off Costa Rica. Major sites of dewatering planned for drilling are mounds, related to mud diapirism/volcanism and precipitation of authigenic carbonates, and large-scale slides related to the subduction of seamounts. Geochemical analysis of methane hydrate and chloride anomalies as well as heat flow modeling of the mounds indicate deeply sourced fluids discharged by clay dehydration at the decollement. Hence, the hydrogeological system at this margin appears to be dominated by the fracture porosity of faults which extend through the overriding plate and provide the paths for fluids liberated by early dehydration reactions from the plate boundary. In order to test the hypothesis of deeply sourced and fault-controlled dewatering sites and to better understand the interactions between gas hydrate formation and dissociation with the fluid ascent from the deep sources, new pre-site survey seismic profiles were acquired using the 36-gun, four-string linear gun array of R/V Marcus Langseth, and a 240 channel streamer with 3000 m of active length. The seismic lines were prestack depth migrated, in which the velocity model is iteratively improved using depth focusing analysis and residual moveout correction on common image point gathers. Improvement of the deep imaging involved multiple attenuation and detailed velocity analysis of the lower sedimentary portions and beneath the basement down to the plate boundary. Our results reveal an upward bending of the bottom simulating reflection (BSR) directly beneath the mounds

  12. Density Functional Exploration of C4H3N Isomers.

    PubMed

    Custer, Thomas; Szczepaniak, Urszula; Gronowski, Marcin; Fabisiewicz, Emilia; Couturier-Tamburelli, Isabelle; Kołos, Robert

    2016-07-28

    Molecules having C4H3N stoichiometry are of astrophysical interest. Two of these, methylcyanoacetylene (CH3C3N) and its structural isomer allenyl cyanide (H2CCCHN), have been observed in interstellar space, while several more have been examined in laboratories. Here we describe, for a broad range of C4H3N isomers, density functional calculations (B3LYP/aug-cc-pVTZ) of molecular parameters including the energetics, geometries, rotational constants, electric dipole moments, polarizabilities, vibrational IR frequencies, IR absorption intensities, and Raman activities. Singlet-triplet splittings as well as singlet vertical electronic excitation energies are given for selected species. The identification of less stable C4H3N molecules, generated in ongoing spectroscopic experiments, relies heavily on these quantum chemical predictions. PMID:27341606

  13. Environmental monitoring at Mound: 1986 report

    SciTech Connect

    Carfagno, D.G.; Farmer, B.M.

    1987-05-11

    The local environment around Mound was monitored for tritium and plutonium-238. The results are reported for 1986. Environmental media analyzed included air, water, vegetation, foodstuffs, and sediment. The average concentrations of plutonium-238 and tritium were within the DOE interim air and water Derived Concentration Guides (DCG) for these radionuclides. The average incremental concentrations of plutonium-238 and tritium oxide in air measured at all offsite locations during 1986 were 0.03% and 0.01%, respectively, of the DOE DCGs for uncontrolled areas. The average incremental concentration of plutonium-238 measured at all locations in the Great Miami River during 1986 was 0.0005% of the DOE DCG. The average incremental concentration of tritium measured at all locations in the Great Miami River during 1986 was 0.005% of the DOE DCG. The average incremental concentrations of plutonium-238 found during 1986 in surface and area drinking water were less than 0.00006% of the DOE DCG. The average incremental concentration of tritium in surface water was less than 0.005% of the DOE DCG. All tritium in drinking water data is compared to the US EPA Drinking Water Standard. The average concentrations in local private and municipal drinking water systems were less than 25% and 1.5%, respectively. Although no DOE DCG is available for foodstuffs, the average concentrations are a small fraction of the water DCG (0.04%). The concentrations of sediment samples obtained at offsite surface water sampling locations were extremely low and therefore represent no adverse impact to the environment. The dose equivalent estimates for the average air, water, and foodstuff concentrations indicate that the levels are within 1% of the DOE standard of 100 mrem. None of these exceptions, however, had an adverse impact on the water quality of the Great Miami River or caused the river to exceed Ohio Stream Standards. 20 refs., 5 figs., 31 tabs.

  14. Sorptive removal of arsenate using termite mound.

    PubMed

    Fufa, Fekadu; Alemayehu, Esayas; Lennartz, Bernd

    2014-01-01

    Long-term consumption of arsenic results in severe and permanent health damages. The aim of the study was to investigate arsenate (As(V)) sorption capacity of termite mound (TM), containing mainly silicon, aluminum, iron and titanium oxides, under batch adsorption setup. The pattern of As(V) removal with varying contact time, solution pH, adsorbent dose, As(V) concentration and competing anions was investigated. Dissolution of the adsorbent was insignificant under the equilibrium conditions. Equilibrium was achieved within 40 min of agitation time. Kinetic data of As(V) adsorption followed well the pseudo-second order equation (R(2) > 0.99). High As(V) removal efficiency (∼ 99%) was observed over a pH range ∼ 3-∼ 10, which is of great importance in the practical application. The Freundlich and Dubinin-Radushkevich isotherms well described (R(2) > 0.99, χ(2) ∼ 0.05) the equilibrium As(V) adsorption, giving a coefficient of adsorption 1.48 mg(1-1/n)L(1/n)/g and a saturation capacity 13.50 mg/g respectively. The obtained value of mean sorption energy (EDR = 13.32 kJ/mol) suggested the chemisorption mechanism of As(V) adsorption on TM. The removal of As(V) was significantly decreased in the presence of phosphate ions. The As(V) loaded adsorbent was successfully regenerated using NaOH solution with insignificant loss of metals. Therefore, the results of the study demonstrated that TM could be considered as a promising adsorbent for the treatment of As(V) in drinking water. PMID:24309232

  15. Marine reservoir effect deduced from 14C dates on marine shells and terrestrial remains at archeological sites in Japan

    NASA Astrophysics Data System (ADS)

    Nakamura, Toshio; Nishida, Iwao; Takada, Hideki; Okuno, Mitsuru; Minami, Masayo; Oda, Hirotaka

    2007-06-01

    Paired marine and terrestrial samples were collected at archeological shell mounds in Kagoshima, Saga and Aichi prefectures and selected from sediment samples bored at the Mawaki archeological site in Ishikawa prefecture, to evaluate the local marine reservoir effect in Japan. The local reservoir corrections, ΔR, were evaluated to be 8 ± 110 and -178 ± 113 14C years for Miyasaka shell mound, -125 ± 50 to -45 ± 49 and -86 ± 48 to -21 ± 50 14C years for Higashimyo shell mound, -46 ± 52, 40 ± 44, -136 ± 44 and 100 ± 44 14C years for Yoshigo shell mound, -255 ± 38 and -146 ± 46 14C years for Kuzubasama shell mound, -71 ± 33, -30 ± 85 and -78 ± 74 14C years on average for C4, C5 and C6 cores, respectively, from the Mawaki site. The existing data along with the present results suggest that the ΔR values obtained for central to southern part of Japan are consistent with zero or a bit negative, but are different from the ΔR values of 200 to 500 14C years for the northern parts of the Japanese archipelago.

  16. The Gale Crater Mound in a Regional Geologic Setting

    NASA Technical Reports Server (NTRS)

    Allen, Carlton C.; Korn, L. K.

    2012-01-01

    The Mars Science Laboratory Rover Curiosity is commencing a two-year investigation of Gale crater and Mt. Sharp, the crater s prominent central mound. Gale is a 155 km, late Noachian / early Hesperian impact crater located near the dichotomy boundary separating the southern highlands from the northern plains. The central mound is composed of layered sedimentary rock, with upper and lower mound units separated by a prominent erosional unconformity (Milliken et al., 2010). The lower mound is of particular interest, as it contains secondary minerals indicative of a striking shift from water-rich to water-poor conditions on early Mars. A key unknown in the history of Gale is the relationship between the sedimentary units in the mound and sedimentary sequences in the surrounding region. We employed orbital remote sensing data to determine if areas within a 1,000 km radius of Gale match the characteristics of sedimentary units in Mt. Sharp. Regions of interest were defined based on: the mound s inferred age (late Noachian to early Hesperian), altitude range (-4,600 m to +400 m), and THEMIS nighttime brightness (a proxy for thermal inertia). This combination of characteristics is matched by two extensive units, the late Noachian subdued cratered unit Npl2 and Noachian / Hesperian undivided material HNu (Greeley and Guest, 1987), located along the dichotomy. Geomorphic units have been mapped within the Gale mound by Thomson et al. (2011) based on albedo, layering and erosional characteristics. Using orbital CTX, MOC and HiRISE images we examined all areas within our regions of interest for analogous geomorphic units in the same altitude ranges as the corresponding units in Mt. Sharp. The most convincing geomorphic analogs to lower mound units, dominated by fine-scale layering and prominent yardangs, were located approximately 200 km northeast and southeast of Gale in late Noachian unit Npl2. The most convincing geomorphic analogs to upper mound layered units are located

  17. HiRISE observations of fractured mounds: Possible Martian pingos

    USGS Publications Warehouse

    Dundas, C.M.; Mellon, M.T.; McEwen, A.S.; Lefort, A.; Keszthelyi, L.P.; Thomas, N.

    2008-01-01

    Early images from the High Resolution Imaging Science Experiment (HiRISE) camera have revealed small fractured mounds in the Martian mid-latitudes. HiRISE resolves fractures on the mound surfaces, indicating uplift, and shows that the mound surface material resembles that of the surrounding landscape. Analysis of Mars Orbiter Camera (MOC) images shows that in Utopia Planitia the mounds lie almost exclusively between 35-45??N. This range coincides with the peak-abundance latitudes of several landforms attributed to ground water or ice, including gullies, and suggests a ground ice-related origin. The best terrestrial analogues for the observed mound morphology are pingos, although some differences are noted. The presence of uncollapsed. pingos would indicate the presence of near-surface ground ice in the Martian mid-latitudes, at depths greater than the ???1 meter sampled by orbital spectrometers. Pingo formation may require near-surface liquid water, which is consistent with a shallow groundwater model for the origin of gullies. Copyright 2008 by the American Geophysical Union.

  18. HiRISE observations of fractured mounds: Possible Martian pingos

    NASA Astrophysics Data System (ADS)

    Dundas, Colin M.; Mellon, Michael T.; McEwen, Alfred S.; Lefort, Alexandra; Keszthelyi, Laszlo P.; Thomas, Nicolas

    2008-02-01

    Early images from the High Resolution Imaging Science Experiment (HiRISE) camera have revealed small fractured mounds in the Martian mid-latitudes. HiRISE resolves fractures on the mound surfaces, indicating uplift, and shows that the mound surface material resembles that of the surrounding landscape. Analysis of Mars Orbiter Camera (MOC) images shows that in Utopia Planitia the mounds lie almost exclusively between 35-45°N. This range coincides with the peak-abundance latitudes of several landforms attributed to ground water or ice, including gullies, and suggests a ground ice-related origin. The best terrestrial analogues for the observed mound morphology are pingos, although some differences are noted. The presence of uncollapsed pingos would indicate the presence of near-surface ground ice in the Martian mid-latitudes, at depths greater than the ~1 meter sampled by orbital spectrometers. Pingo formation may require near-surface liquid water, which is consistent with a shallow groundwater model for the origin of gullies.

  19. The Big E (Energy). 4-H Member Guide, Unit 2.

    ERIC Educational Resources Information Center

    Caldwell, William; And Others

    This activity and record book is designed for unit 2 (ages 12-14) of the Nebraska 4-H Energy Project. Aims, energy attitudes to be developed, and instructions are provided for each activity. Activities include: (1) a word search of energy-related words (with definitions provided); (2) determining fuel waste; (3) reading electric/gas meters and…

  20. Textile Science Leader's Guide. 4-H Textile Science.

    ERIC Educational Resources Information Center

    Scholl, Jan

    This instructor's guide provides an overview of 4-H student project modules in the textile sciences area. The guide includes short notes explaining how to use the project modules, a flowchart chart showing how the project areas are sequenced, a synopsis of the design and content of the modules, and some program planning tips. For each of the…

  1. Effectiveness of the Indiana 4-H Tractor Program: Alumni Perceptions.

    ERIC Educational Resources Information Center

    Carrabba, James J., Jr.; Talbert, B. Allen; Field, William E.; Tormoehlen, Roger

    2001-01-01

    Responses from Indiana 4-H tractor driving contestants 1982-197 (n=139) showed that 74% were employed on farms; most felt the contests effectively taught tractor safety and made them generally aware of safety. However, many still engaged in risky behaviors such as not wearing seatbelts in tractors with rollover protective structures or allowing…

  2. "Ohio 4-H CARTEENS": Peer Intervention Safety Program.

    ERIC Educational Resources Information Center

    Cropper, Rebecca J.

    1999-01-01

    Ohio 4-H's CARTEENS seeks to reduce juvenile traffic violations in a program designed and presented by teen peer educators with guidance and technical assistance from the state highway patrol. Teens examined court data to determine content, which includes defensive driving, rural road safety, and dealing with peer pressure. (SK)

  3. Fashion Revue. 4-H Textile Science Activity Guide.

    ERIC Educational Resources Information Center

    Scholl, Jan

    This publication was developed to help students participating in Fashion Review, a 4-H event in which students model a clothing outfit and accessories and are judged on their modeling ability, their presentation, and how well the clothing and accessory choices complement the students' skin tones, hair color, figure or physique, personality, and…

  4. Minnesota 4-H Youth Program Quality Improvement Model

    ERIC Educational Resources Information Center

    Herman, Margo; Grant, Samantha

    2015-01-01

    The University of Minnesota Extension Center for Youth Development made an organizational decision in 2011 to invest in a system-wide approach to implement youth program quality into the 4-H program using the Youth Program Quality Assessment (YPQA) tool. This article describes the four key components to the Minnesota Youth Program Quality…

  5. The Big E (Energy). 4-H Member Guide, Unit 3.

    ERIC Educational Resources Information Center

    Caldwell, William; And Others

    This activity and record book is designed for unit 3 (ages 15-19) of the Nebraska 4-H Energy Project. Aims, energy attitudes to be developed, and instructions are provided for each activity. Activities include: (1) determining ways to reduce energy waste with hot water heaters; (2) making personal choices about using appliances; (3) conducting a…

  6. Marketing Strategies for Recruiting 4-H Members in West Virginia.

    ERIC Educational Resources Information Center

    Wingenbach, Gary J.; Nestor, Cheryl; Lawrence, Layle D.; Gartin, Stacy A.; Woloshuk, Jean; Mulkeen, Patricia

    2000-01-01

    According to a survey of 174 West Virginia 4-H members aged 13-18, the Internet and word of mouth were most effective in recruiting new members. Active messages stressing camps, fun, and friendship had the most influence on retention. A statewide marketing plan was recommended. (SK)

  7. Keys To The Kansas Environment. 4-H School Enrichment Program.

    ERIC Educational Resources Information Center

    Kansas State Univ., Manhattan. Extension Service.

    The 4-H Club packet for preschool and elementary school children contains nine "keys", or short learning exercises, designed to enrich science and environmental education both in and out of the classroom. Each "key" includes the purpose of the activity, the intended audience, the best time of the year for the activity, background information,…

  8. Folkpatterns 4-H Leader's Guide: A Cultural Heritage Project.

    ERIC Educational Resources Information Center

    Kozma, LuAnne Gaykowski

    Folkpatterns is a 4-H program in which young people investigate folklore, cultural traditions, and local history. These materials include a leader's guide and Folkpatterns activities. The leader's guide provides information for leading a Folkpatterns project and 12 sample meeting plans to be used with Folkpatterns members or to be adapted for use…

  9. CONSERVING OUR NATURAL RESOURCES, A 4-H LEADER'S GUIDE.

    ERIC Educational Resources Information Center

    AMICK, W. ROBERT; AND OTHERS

    AN EFFECTIVE 4-H CONSERVATION PROGRAM IS DEVELOPED AROUND THE FOLLOWING BASIC CONCEPTS--(1) MAN IS A PART OF THE NATURAL WORLD, IN WHICH THERE ARE MANY VALUABLE MATERIALS, (2) MAN HAS LEARNED TO USE MANY OF THOSE MATERIALS FOR HUMAN SUSTENANCE AND BETTERMENT, AND (3) MAN'S ECONOMIC, SOCIAL, AND GENERAL WELFARE IS LARGELY DEPENDENT UPON THE MANNER…

  10. Self-Protection: A New Approach to 4-H Health.

    ERIC Educational Resources Information Center

    Wright, Sharon K. B.

    This document introduces the issue of self-protection as the Minnesota 4-H Youth Development response to self-destructive behavior among adolescents. It presents findings from a statewide survey of over 36,000 secondary school students using the Minnesota Adolescent Health Survey. Responses are given in the areas of health, school attitudes,…

  11. The Evaluation Attitudes and Practices of 4-H Educators

    ERIC Educational Resources Information Center

    Lekies, Kristi S.; Bennett, Amanda M.

    2011-01-01

    Extension educators are expected to conduct program evaluation. An Internet survey was sent to county 4-H educators in Ohio to examine their evaluation attitudes and practices, as well as barriers to conducting evaluation. Respondents indicated a range of attitudes about evaluation and limited use of different designs and methods. Having enough…

  12. Implementing and Assessing 4-H Educational Activity Kits for Children

    ERIC Educational Resources Information Center

    Scheer, Scott D.; Yeske, Janine; Zimmer, Bruce

    2011-01-01

    Educational activity kits were developed and implemented through a statewide effort for 4-H Youth Development Extension programs serving 5-8 year-old children. The purpose of the kits was to promote life skills in children and assess the learning environment. Data was collected based on the observations of 577 children across 22 counties. Findings…

  13. A Phenomenological Look at 4-H Volunteer Motives for Service

    ERIC Educational Resources Information Center

    Schrock, Jessalyn; Kelsey, Kathleen D.

    2013-01-01

    Volunteers play a vital role in 4-H programs. Without their service, many programs would not be possible. Understanding volunteer motives provides Extension educators with tools for finding high-quality volunteers. The research reported here used McClelland's (1985) framework for motivation (affiliation, achievement, and power) and…

  14. Cell Sorting in the Mound Stage of Dictyostelium

    NASA Astrophysics Data System (ADS)

    Jiang, Yi; Levine, Herbert; Glazier, James

    1998-03-01

    In the mound stage of slime mold Dictyostelium discoideum, cells differentiated into two types: pre-stalk and pre-spore. Pre-stalk cells sort and form a tip at the apex of the mound of prespore cells. How this pattern forms is as yet unknown. A cellular level model allows us to simulate both differential cell adhesion and chemotaxis, two principle mechanisms for cell migration. Simulations show that with differential adhesion only, pre-stalk cells move to the surface of the mound but form no tip. With chemotaxis driven by an outgoing circular wave only, a tip forms but contains both pre-stalk and pre-spore cells. Only for a narrow range of relative strengths between differential adhesion and chemotaxis, can both mechanisms work in concert to form a tip which contains only pre-stalk cells. The simulations provide a method to determine the processes necessary for patterning and suggest a series of further experiments.

  15. Environmental survey preliminary report, Mound Plant, Miamisburg, Ohio

    SciTech Connect

    Not Available

    1987-03-01

    This report presents the preliminary findings from the first phase of the Environmental Survey of the United States Department of Energy (DOE) Mound Plant, conducted August 18 through 29, 1986. The objective of the Survey is to identify environmental problems and areas of environmental risk associated with the Mound Plant. The Survey covers all environmental media and all areas of environmental regulation. It is being performed in accordance with the DOE Environmental Survey Manual. The on-site phase of the Survey involves the review of existing site environmental data, observations of the operations carried on at the Mound Plant, and interviews with site personnel. The Survey found no environmental problems at the Mound Plant that represent an immediate threat to human life. The environmental problems identified at the Mound Plant by the Survey confirm that the site is confronted with a number of environmental problems which are by and large a legacy from past practices at a time when environmental problems were less well understood. Theses problems vary in terms of their magnitude and risk, as described in this report. Although the sampling and analysis performed by the Mound Plant Survey will assist in further identifying environmental problems at the site, a complete understanding of the significance of some of the environmental problems identified requires a level of study and characterization that is beyond the scope of the Survey. Actions currently under way or planned at the site, particularly the Phase II activities of the Comprehensive Environmental Analysis and Response Program (CEARP) as developed and implemented by the Albuquerque Operations Office, will contribute toward meeting this requirement. 85 refs., 24 figs., 20 tabs.

  16. Perennial mounds in Utopia Planitia: (HiRISE) Evidence of a Glacial Origin

    NASA Astrophysics Data System (ADS)

    Soare, R. J.; Osinski, G. R.; Thomson, L.

    2009-03-01

    Here, we use HiRISE and high-resolution MOC images to discuss sub-kilometer pingo-like mounds in Utopia Planita. The mounds show geological characteristics consistent with formation by glacial accumulation, and ablation by sublimation.

  17. Shallow water mud-mounds of the Early Devonian Buchan Group, East Gippsland, Australia

    NASA Astrophysics Data System (ADS)

    Tosolini, A.-M. P.; Wallace, M. W.; Gallagher, S. J.

    2012-12-01

    The Lower Devonian Rocky Camp Member of the Murrindal Limestone, Buchan Group of southeastern Australia consists of a series of carbonate mud-mounds and smaller lagoonal bioherms. The Rocky Camp mound is the best exposed of the mud-mounds and has many characteristics in common with Waulsortian (Carboniferous) mounds. Detailed paleoecological and sedimentological studies indicate that the mound initially accumulated in the photic zone, in contrast to most of the previously recorded mud-mounds. Five facies are present in the mud-mound: a Dasycladacean Wackestone Facies at the base of the mound represents a moderate energy, shallow water bank environment within the photic zone. A Crinioidal Wackestone Facies was deposited in a laterally equivalent foreslope setting. A Poriferan-Crinoidal Mudstone Facies developed in a quiet, deeper water, lee-side mound setting associated with a minor relative sea-level rise. A Stromatoporoid-Coralline Packstone Facies in the upper part of the mound deposited in a high-energy, fair-weather wave base, mound-front environment. The crest of the mound is represented by a Crinoidal-Receptaculitid Packstone Facies indicative of a moderate-energy mound-top environment in the photic zone, sheltered by the mound-front stromatoporoid-coral communities. A mound flank facies is present on the southern side of the mound and this consists of high-energy crinoidal grainstones. Mud-mound deposition was terminated by a transgression that deposited dark gray, fossil-poor marl of the overlying Taravale Formation. The Rocky Camp mound appears to have originated in shallow water photic zone conditions and grew into a high-energy environment, with the mound being eventually colonized by corals and stromatoporoids. The indications of a high-energy environment during later mound growth (growth form of colonial metazoans and grainstones of the flanking facies) suggest that the micrite in the mound was autochthonous and implies the presence of an energy

  18. Native American Calendric Orientation at Town Creek Indian Mound

    NASA Astrophysics Data System (ADS)

    Tiede, V. R.

    2005-12-01

    Evidence is presented for a newly discovered set of interior solar alignments - the equinox and summer solstice meridian transits - at a prehistoric Native American structure in the Southeast United States. Because North Carolina's Town Creek Indian Mound is the only Mississippian temple-mound accurately reconstructed from overhead photo-mosaics, the site is uniquely suited for applying the techniques of astro-archaeology (G. S. Hawkins 1983). Implications of the new findings for interpreting Muskogean ethnographic literature as well as future archaeoastronomical research at other Southeastern sites (e.g., Ocmulgee National Monument Earth Lodge, Georgia) are discussed.

  19. Analysis of Subsidence Data for the Bryan Mound Site, Texas

    SciTech Connect

    Bauer, Stephen J.

    1999-07-01

    The elevation change data measured at the Bryan Mound Strategic Petroleum Reserve (SPR) site over the last 16+ years has been studied and a model utilized to project elevation changes into the future. The subsidence rate at Bryan Mound is low in comparison with other Strategic Petroleum Reserve sites and has decreased with time due to the maintenance of higher operating pressures and the normal decrease in creep closure rate of caverns with time. However, the subsidence at the site is projected to continue. A model was developed to project subsidence values 20 years into the future; no subsidence related issues are apparent from these projections.

  20. New Jersey 4-H Goat Extravaganza: Efficiently Meeting the Educational Needs of 4-H Goat Project Members, Volunteers, and Parents

    ERIC Educational Resources Information Center

    Ripberger, Chad

    2014-01-01

    The 4-H Goat Extravaganza maximizes limited resources to help youth and adults develop knowledge and skills in goat care and management. It capitalizes on the talents and interests of volunteers to efficiently combine a goat-themed art show, team presentation contest, quiz bowl, skillathon, and adult workshop into 1 day. This article outlines the…

  1. Water Worlds. 4-H Member's Guide M-5-18; 4-H Leaders Guide L-5-18.

    ERIC Educational Resources Information Center

    Hawkes, Janet E.; And Others

    This pocket folder of materials is designed to provide children aged 9 to 12 with an opportunity to explore and observe aquatic environments. The package includes a 4-H Leader's guide, member's guide, and supplementary materials. The leader's guide contains safety considerations, tips and techniques, and additional activities for getting started…

  2. Starting and Maintaining a Marine Aquarium: 4-H Members Guide [and] 4-H Member's Project Record Book.

    ERIC Educational Resources Information Center

    Crenshaw, Neil

    The guide and the project record book included in this document are designed for 4-H members who would like to start a salt-water aquarium project. The guide includes the following topics: (1) general requirements for salt-water aquariums; (2) directions for making an aquarium; (3) suggestions for where to locate it; (4) pros and cons of using…

  3. The Gale Crater Mound in a Regional Geologic Setting: Mapping and Probing Surrounding Outcrops for Areas Akin to the Central Mound at Gale

    NASA Technical Reports Server (NTRS)

    Korn, Lisa; Allen, Carlton

    2013-01-01

    There are several hypotheses on the origin of Gale Crater s central mound. These include ground water upwelling [1], aeolian, ice, volcanic [1-3], lacustrine [1-3], hydrothermal [1-3], and polar deposits [2]. The Mars Science Laboratory rover, Curiosity, landed in Gale Crater on August 6, 2012. It is currently analyzing samples along its traverse towards a channel and layered deposits that will provide insight into the sedimentary history of the crater [4]. Located at 5S, 138E, Gale is a 155km diameter, Late Noachian/Early Hesperian crater. It is situated along the southern highlands/northern lowlands dichotomy boundary and contains a central mound that rises approximately 5km from the crater floor [1]. The highest parts of Mt. Sharp are higher than the northern rim, but are roughly the same height as the southern rim. Mt. Sharp is divided into an upper mound and a lower mound, which are separated by an erosional unconformity [2]. The lower mound s sequences span the Late Noachian/Early Hesperian Epoch [1], while the upper mound s age is poorly constrained. The lower mound s sequences feature parallel beds of varying thickness, albedo, texture, and dip angle that are eroded into channels and yardangs [2]. The upper mound has finer layers at higher angles [1] with yardangs, serrated erosional patterns, and lobate features [3]. The lower mound also exhibits an upward progression of phyllosilicate to sulfate rich sediments, contrasting the upper mound s lack of hydrated minerals [4].

  4. Radiocarbon dating of large termite mounds of the miombo woodland of Katanga, DR Congo

    NASA Astrophysics Data System (ADS)

    Erens, Hans; Boudin, Mathieu; Mees, Florias; Dumon, Mathijs; Mujinya, Basile; Van Strydonck, Mark; Baert, Geert; Boeckx, Pascal; Van Ranst, Eric

    2015-04-01

    The miombo woodlands of South Katanga (D.R. Congo) are characterized by a high spatial density of large conic termite mounds built by Macrotermes falciger (3 to 5 ha-1, ~5 m high, ~15 m in diameter). The time it takes for these mounds to attain this size is still largely unknown. In this study, the age of four of these mounds is determined by 14C-dating the acid-insoluble organic carbon fraction of samples taken along the central vertical axis of two active and two abandoned mounds. The age sequence in the active mounds is erratic, but the results for the abandoned mounds show a logical increase of 14C-age with depth. The ages measured at 50 cm above ground level were 2335 - 2119 cal yr BP for the large abandoned mound (630 cm high), and 796 - 684 cal yr BP for the small abandoned mound (320 cm high). Cold-water-extractable organic carbon (CWEOC) measurements combined with spectroscopic analysis revealed that the lower parts of the active mounds may have been contaminated with recent carbon that leached from the active nest. Nonetheless, this method appears to provide reliable age estimates of large, abandoned termite mounds, which are older than previously estimated. Furthermore, historical mound growth rates seem to correspond to past temperature changes, suggesting a relation between past environmental conditions and mound occupancy. Keywords : 14C, water-extractable carbon, low-temperature combustion

  5. 29. Overall view taken from top of water storage mound ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    29. Overall view taken from top of water storage mound showing building 104, mess hall in lower left, building 101, administration, recreation, and storage building in center, and building 103, non-commissioned officers quarters and enlisted men barracks on far right, looking northeast - Nike Missile Battery MS-40, County Road No. 260, Farmington, Dakota County, MN

  6. Stable isotope sales: Mound customer and shipment summaries, FY 1988

    SciTech Connect

    Flayler, K.A.

    1990-04-23

    This report lists Mound's sales of stable isotopes of noble gases, carbon, oxygen, nitrogen, chlorine, bromine, and sulfur for fiscal year 1988. Purchasers are listed alphabetically and are divided into domestic and foreign groups. Cross-reference indexes by location and by isotope purchases are included for all customers. 3 tabs.

  7. 28. Overall view taken from top of water storage mound ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    28. Overall view taken from top of water storage mound showing building 154, missile assembly building on right, Minnesota Department of Transportation communication tower in center, and Minnesota Bureau of Mines wind tunnel on left, looking southwest toward launch pad area - Nike Missile Battery MS-40, County Road No. 260, Farmington, Dakota County, MN

  8. VIEW LOOKING SOUTHWEST AT THE EARTH MOUND USED TO ENCASE ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    VIEW LOOKING SOUTHWEST AT THE EARTH MOUND USED TO ENCASE THE INSTRUMENTATION AND CONTROL TANKS AND PROTECT EQUIPMENT. NOTE THE TEST STAND IN THE BACKGROUND RIGHT. - Marshall Space Flight Center, Redstone Rocket (Missile) Test Stand, Dodd Road, Huntsville, Madison County, AL

  9. Imported Fire Ant Mound Building in Response to Simulated Rainfall

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Imported fire ant (Solenopsis richteri x invicta) mounds in northeastern Mississippi were subjected to four treatments from late July through early September, 2006: application of water (7.5 L) and placement of an inverted 19 L bucket on top; application of water only; application of an inverted buc...

  10. 32. Overall view taken from top of water storage mound ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    32. Overall view taken from top of water storage mound showing building 154, missile assembly building in center, and building 161, fallout shelter in lower right corner, looking west - Nike Missile Battery MS-40, County Road No. 260, Farmington, Dakota County, MN

  11. Test fire environmental testing operations at Mound Applied Technologies

    SciTech Connect

    1992-03-01

    This paper describes Mound Laboratory`s environmental testing operations. The function of environmental testing is to perform quality environmental (thermal, mechanical, spin, resistance, visual) testing/conditioning of inert/explosive products to assure their compliance with specified customer acceptance criteria. Capabilities, organization, equipment specifications, and test facilities are summarized.

  12. Stable isotope sales: Mound customer and shipment summaries, FY 1986

    SciTech Connect

    Kramer, L.R.; Flayler, K.A.

    1988-05-20

    A listing is given of Mound's sales of stable isotopes of noble gases, carbon, oxygen, nitrogen, chlorine, and sulfur for fiscal year 1986. Purchasers are listed alphabetically and are divided into domestic and foreign groups. Cross-reference indexes by location and by isotope are included for all customers. 3 tabs.

  13. Stable isotopes sales: Mound customer and shipment summaries, FY 1985

    SciTech Connect

    Flayler, K.A.

    1987-12-15

    A listing is given of Mound's sales of stable isotopes of noble gases, deuterium, carbon, oxygen, nitrogen, chlorine, bromine, and sulfur for fiscal year 1985. Purchasers are listed alphabetically and are divided into domestic and foreign groups. A cross-reference index by location is included for domestic and foreign customers. Cross-reference listings by isotope purchased are included for all customers.

  14. Beaufort Sea deep-water gas hydrate recovery from a seafloor mound in a region of widespread BSR occurrence

    USGS Publications Warehouse

    Hart, Patrick E.; Pohlman, John W.; Lorenson, T.D.; Edwards, Brian D.

    2011-01-01

    Gas hydrate was recovered from the Alaskan Beaufort Sea slope north of Camden Bay in August 2010 during a U.S. Coast Guard Cutter Healy expedition (USCG cruise ID HLY1002) under the direction of the U.S. Geological Survey (USGS). Interpretation of multichannel seismic (MCS) reflection data collected in 1977 by the USGS across the Beaufort Sea continental margin identified a regional bottom simulating reflection (BSR), indicating that a large segment of the Beaufort Sea slope is underlain by gas hydrate. During HLY1002, gas hydrate was sampled by serendipity with a piston core targeting a steep-sided bathymetric high originally thought to be an outcrop of older, exposed strata. The feature cored is an approximately 1100m diameter, 130 m high conical mound, referred to here as the Canning Seafloor Mound (CSM), which overlies the crest of a buried anticline in a region of sub-parallel compressional folds beneath the eastern Beaufort outer slope. An MCS profile shows a prominent BSR upslope and downslope from the mound. The absence of a BSR beneath the CSM and occurrence of gas hydrate near the summit indicates that free gas has migrated via deep-rooted thrust faults or by structural focusing up the flanks of the anticline to the seafloor. Gas hydrate recovered from near the CSM summit at a subbottom depth of about 5.7 meters in a water depth of 2538 m was of nodular and vein-filling morphology. Although the hydrate was not preserved, residual gas from the core liner contained >95% methane by volume when corrected for atmospheric contamination. The presence of trace C4+hydrocarbons (<0.1% by volume) confirms at least a minor thermogenic component. Authigenic carbonates and mollusk shells found throughout the core indicate sustained methane-rich fluid advection and possible sediment extrusion contributing to the development of the mound. Blister-like inflation of the seafloor caused by formation and accumulation of shallow hydrate lenses is also a likely factor in CSM

  15. Growth and form of the mound in Gale Crater, Mars: Slope wind enhanced erosion and transport

    NASA Astrophysics Data System (ADS)

    Kite, Edwin S.; Lewis, Kevin W.; Lamb, Michael P.; Newman, Claire E.; Richardson, Mark I.

    2013-05-01

    Ancient sediments provide archives of climate and habitability on Mars. Gale Crater, the landing site for the Mars Science Laboratory (MSL), hosts a 5-km-high sedimentary mound (Mount Sharp/Aeolis Mons). Hypotheses for mound formation include evaporitic, lacustrine, fluviodeltaic, and aeolian processes, but the origin and original extent of Gale’s mound is unknown. Here we show new measurements of sedimentary strata within the mound that indicate ˜3° outward dips oriented radially away from the mound center, inconsistent with the first three hypotheses. Moreover, although mounds are widely considered to be erosional remnants of a once crater-filling unit, we find that the Gale mound’s current form is close to its maximal extent. Instead we propose that the mound’s structure, stratigraphy, and current shape can be explained by growth in place near the center of the crater mediated by wind-topography feedbacks. Our model shows how sediment can initially accrete near the crater center far from crater-wall katabatic winds, until the increasing relief of the resulting mound generates mound-flank slope winds strong enough to erode the mound. The slope wind enhanced erosion and transport (SWEET) hypothesis indicates mound formation dominantly by aeolian deposition with limited organic carbon preservation potential, and a relatively limited role for lacustrine and fluvial activity. Morphodynamic feedbacks between wind and topography are widely applicable to a range of sedimentary and ice mounds across the Martian surface, and possibly other planets.

  16. Diversity of fungi from the mound nests of Formica ulkei and adjacent non-nest soils.

    PubMed

    Duff, Lyndon B; Urichuk, Theresa M; Hodgins, Lisa N; Young, Jocelyn R; Untereiner, Wendy A

    2016-07-01

    Culture-based methods were employed to recover 3929 isolates of fungi from soils collected in May and July 2014 from mound nests of Formica ulkei and adjacent non-nest sites. The abundance, diversity, and richness of species from nest mounds exceeded those of non-mound soils, particularly in July. Communities of fungi from mounds were more similar to those from mounds than non-mounds; this was also the case for non-mound soils with the exception of one non-mound site in July. Species of Aspergillus, Paecilomyces, and Penicillium were dominant in nest soils and represented up to 81.8% of the taxa recovered. Members of the genus Aspergillus accounted for the majority of Trichocomaceae from nests and were represented almost exclusively by Aspergillus navahoensis and Aspergillus pseudodeflectus. Dominant fungi from non-mound sites included Cladosporium cladosporioides, Geomyces pannorum, and species of Acremonium, Fusarium, Penicillium, and Phoma. Although mound nests were warmer than adjacent soils, the dominance of xerotolerant Aspergillus in soils from mounds and the isolation of the majority of Trichocomaceae at 25 and 35 °C suggests that both temperature and water availability may be determinants of fungal community structure in nests of F. ulkei.

  17. How cold-water coral mounds modify their physical environment and therefore influence reef development

    NASA Astrophysics Data System (ADS)

    Mienis, F.; Duineveld, G.; Lavaleye, M.; van Haren, H.; Mohn, C.; Cyr, F.

    2015-12-01

    Cold-water coral framework acts as a sediment trap and as a result kilometres long and up to 360m high mound structures have formed on the SE Rockall Bank. Earlier observations showed that most of the mounds have their summits around 550 m water depth and summits have been reported as being covered with living coral. Pelagia cruises in 2012 and 2013 revealed completely new insights in mound development. Video transects across mounds with different morphology showed that summits of the highest and largest mounds are presently not covered by living coral as opposed to smaller and lower mounds which are covered with a thriving living coral framework. Measurements in the water column with CTD and near-bottom with benthic landers and thermistor string showed that turbulence is likely the most important factor influencing nutrient and food supply and thus coral growth. It seems that the large mounds have outgrown themselves and that their relatively large size and flat summits are limiting turbulence, thereby limiting oxygen, nutrient and food replenishment. Redistribution of nutrients, oxygen and food is vital for ecosystem functioning and reef development. The presence of a healthy coral cover on the summits of the small mounds was also shown by the vertical mound growth rate measured in sediment cores. These showed fourfold higher sedimentation rates during the Holocene on small mounds compared to highest mounds.

  18. Diversity of fungi from the mound nests of Formica ulkei and adjacent non-nest soils.

    PubMed

    Duff, Lyndon B; Urichuk, Theresa M; Hodgins, Lisa N; Young, Jocelyn R; Untereiner, Wendy A

    2016-07-01

    Culture-based methods were employed to recover 3929 isolates of fungi from soils collected in May and July 2014 from mound nests of Formica ulkei and adjacent non-nest sites. The abundance, diversity, and richness of species from nest mounds exceeded those of non-mound soils, particularly in July. Communities of fungi from mounds were more similar to those from mounds than non-mounds; this was also the case for non-mound soils with the exception of one non-mound site in July. Species of Aspergillus, Paecilomyces, and Penicillium were dominant in nest soils and represented up to 81.8% of the taxa recovered. Members of the genus Aspergillus accounted for the majority of Trichocomaceae from nests and were represented almost exclusively by Aspergillus navahoensis and Aspergillus pseudodeflectus. Dominant fungi from non-mound sites included Cladosporium cladosporioides, Geomyces pannorum, and species of Acremonium, Fusarium, Penicillium, and Phoma. Although mound nests were warmer than adjacent soils, the dominance of xerotolerant Aspergillus in soils from mounds and the isolation of the majority of Trichocomaceae at 25 and 35 °C suggests that both temperature and water availability may be determinants of fungal community structure in nests of F. ulkei. PMID:27192606

  19. Are termite mounds biofilters for methane? - Challenges and new approaches to quantify methane oxidation in termite mounds

    NASA Astrophysics Data System (ADS)

    Nauer, Philipp A.; Hutley, Lindsay B.; Bristow, Mila; Arndt, Stefan K.

    2015-04-01

    Methane emissions from termites contribute around 3% to global methane in the atmosphere, although the total source estimate for termites is the most uncertain among all sources. In tropical regions, the relative source contribution of termites can be far higher due to the high biomass and relative importance of termites in plant decomposition. Past research focused on net emission measurements and their variability, but little is known about underlying processes governing these emissions. In particular, microbial oxidation of methane (MOX) within termite mounds has rarely been investigated. In well-studied ecosystems featuring an oxic matrix above an anoxic methane-producing habitat (e.g. landfills or sediments), the fraction of oxidized methane (fox) can reach up to 90% of gross production. However, conventional mass-balance approaches to apportion production and consumption processes can be challenging to apply in the complex-structured and almost inaccessible environment of a termite mound. In effect, all field-based data on termite-mound MOX is based on one study that measured isotopic shifts in produced and emitted methane. In this study a closed-system isotope fractionation model was applied and estimated fox ranged from 10% to almost 100%. However, it is shown here that by applying an open-system isotope-pool model, the measured isotopic shifts can also be explained by physical transport of methane alone. Different field-based methods to quantify MOX in termite mounds are proposed which do not rely on assumptions of physical gas transport. A simple approach is the use of specific inhibitors for MOX, e.g. difluoromethane (CH2F2), combined with chamber-based flux measurements before and after their application. Data is presented on the suitability of different inhibitors and first results of their application in the field. Alternatively, gas-tracer methods allow the quantification of methane oxidation and reaction kinetics without knowledge of physical gas

  20. Reef mounds indicate timing of hydrocarbon charge off Seychelles

    SciTech Connect

    Plummer, P.

    1998-07-06

    Carbonate mounds developed on Coetivy Bank and the northern Seychelles Plateau appear to have formed in response to pulses of hydrocarbon fluid migration along underlying faults during the late Paleocene and late Eocene. Gas chimneys emanating from these mounds are evident on seismic data, while gas sniffer and/or UV fluorescence anomalies have been recorded in the overlying waters. Such a combination of hydrocarbon anomalies is indicative of minor active gas seepage and confirms the prospectivity of these features and their underlying sequences. Recently it has also been realized that both authigenic and biogenic carbonates proliferate above faults from which hydrocarbon seepage occurs, forming chemosynthetic reefs. When identified on seismic data, such reef/fault associations constitute seismic hydrocarbon indicators (SHIs), and the reefs/faults off Seychelles have been interpreted as SHIs. This paper discusses the geology, source rocks, thermal history, and chemosynthetic reefs.

  1. 4H-SiC detectors for ultraviolet light monitoring

    NASA Astrophysics Data System (ADS)

    Mazzillo, M.; Sciuto, A.; Badalà, P.; Carbone, B.; Russo, A.; Coffa, S.

    2015-02-01

    Silicon Carbide (SiC) provides the unique property of near-perfect visible blindness and very high signal-to-noise ratio due to the high quantum efficiency and low dark current even at high temperature. These features make SiC the best available material for the manufacturing of visible blind semiconductor ultraviolet (UV) light detectors. Thanks to their properties, SiC detectors have been extensively used in fact for flame detection monitoring, UV sterilization and astronomy. Here we report on the electrical and optical performance of patterned thin metal film NiSi/4H-SiC vertical Schottky photodiodes with different semiconductor exposed area suitably designed for UV light monitoring.

  2. Experimental investigations of the hypernucleus Λ4H

    NASA Astrophysics Data System (ADS)

    Achenbach, P.; Schulz, F.; Aulenbacher, S.; Beričič, J.; Bleser, S.; Böhm, R.; Bosnar, D.; Correa, L.; Distler, M. O.; Esser, A.; Fonvieille, H.; Friščić, I.; Fujii, Y.; Fujita, M.; Gogami, T.; Kanda, H.; Kaneta, M.; Kegel, S.; Kohl, Y.; Kusaka, W.; Margaryan, A.; Merkel, H.; Mihovilovič, M.; Müller, U.; Nagao, S.; Nakamura, S. N.; Pochodzalla, J.; Sanchez Lorente, A.; Schlimme, B. S.; Schoth, M.; Sfienti, C.; Širca, S.; Steinen, M.; Takahashi, Y.; Tang, L.; Thiel, M.; Tsukada, K.; Tyukin, A.; Weber, A.

    2016-03-01

    Negatively charged pions from two-body decays of stopped Λ4H hypernuclei were studied in 2012 at the Mainz Microtron MAMI, Germany. The momenta of the decay-pions were measured with unprecedented precision by using high-resolution magnetic spectrometers. A challenge of the experiment was the tagging of kaons from associated K+∧ production off a Be target at very forward angles. In the year 2014, this experiment was continued with a better control of the systematic uncertainties, with better suppression of coincident and random background, improved particle identification, and with higher luminosities. Another key point of the progress was the improvement in the absolute momentum calibration of the magnetic spectrometers.

  3. A Reevaluation of the DeKalb Mounds of Northern Illinois

    NASA Astrophysics Data System (ADS)

    Konen, M.; Curry, B.

    2007-12-01

    We re-examined the classic DeKalb Mounds of Northern Illinois in order to better understand their genesis, morphology, spatial distribution, and usefulness in reconstructing deglacial and postglacial environments. Flemal et al. (1973) interpreted the mounds to be relict pingos resulting from an intense periglacial environment during the late Wisconsin. Thousands of mounds occur in the study area. The mounds range in size from 20 m to more than 5 km in diameter and typically rise 1 to 8 m above the surrounding loess mantled till surface. These low relief mounds are composed of either a raised border surrounding a low center ("donuts") or are flat-topped ("pancakes"). Modern soil properties are strongly related to mound position and subtle sedimentologic and topographic changes. In some locations multiple mounds appear to be superimposed on one another. The typical mound stratigraphy includes subglacial diamicton at the base, less than 1 m of glaciofluvial sands and gravels or debris flow diamicton, 1 to 6 m of fossiliferous, rhythmically bedded lake sediment, 0.3 to 3 m of glaciofluvial sands and gravels or debris flow diamicton, all capped by approximately 1.2 m of loess. The lake sediment is rich in ostracodes and tundra plant remains. Smaller mounds are typically symmetrical while the larger mounds are more elliptical in shape with a long axis trending northeast to southwest. Many of the larger mounds appear to be aggregates of smaller lakes that coalesced as glacial ice stagnated. Our reinterpretation of the mounds is that there genesis is related to deglaciation and ice-stagnation and not to post glacial permafrost processes. We interpret all of the DeKalb Mounds to be ice-walled lakes and not pingos.

  4. Extended defects in 4H-silicon carbide homoepitaxial layers

    NASA Astrophysics Data System (ADS)

    Zhang, Xuan

    The purpose of this thesis is to study the structure of extended defects in 4H-SIC homoepitaxial layers, and to identify their nucleation mechanisms. Characteristics of basal plane dislocations in 4H-SiC epilayers were investigated in a comprehensive manner, including their morphologies, Burgers' vectors, positions, and correlation with the extended defects propagating from the substrate. Plan-view transmission x-ray topography was the major characterization technique used in this study. Complementary data was obtained by KOH etching and optical microscopy. Trace of glide was detected on every basal plane dislocation in the entire 3-inch epilayer. In the center area of the epi-wafer, the glide can extend to macroscopic distance and form edge-type dislocations at the epilayer/surface interface. During the motion, dislocation half loop arrays were found to nucleate at the growth front. The magnitude of the resolved shear stress was estimated based on the radius of curvature of the dislocation lines. It surpassed the critical resolved shear stress at the epitaxial growth temperature. The stress was identified to be compressive in the epilayer. Its origin was studied. Nitrogen-doping-difference-induced misfit strain was excluded as the source of the stress. The structures of two morphological defects, 'carrots' and 'arrows', were studied. Cross-section x-ray topography was used to image the structure of carrot defect in whole. The defect was found to nucleate at the epilayer/substrate interface on a threading screw dislocation propagating from the substrate. Its structure was mainly composed of a prismatic stacking fault and a Frank-type basal plane stacking fault. The arrow defect was found to be produced by a spheroid shape inclusion in the volume of the epilayer. Zone axis diffraction pattern under transmission electron microscope identified the nature of the inclusion as 3C-SIC. It was determined to nucleate at the substrate surface contaminations.

  5. Non-dune eolian sand in Indian mounds

    NASA Astrophysics Data System (ADS)

    Tanner, William F.

    1980-02-01

    Indian mounds, near Careyville, Florida, about 2.0 m high, are located on hillsides and hilltops 10 to 20 m above the floodplain of the nearest river (Choctawhatchee). Each mound is composed largely of quartz sand, with a scattering of artefacts and stream pebbles (not in layers), but with no visible bedding. Probability plots showed 25 Gaussian distributions, 18 having the 'dune hump', three having the 'surf break' and nine being doubly-truncated or having other patterns of unknown or uncertain origin. The surf breaks probably were inherited from pre-Pleistocene marine terraces in the area. The pebbles and the sand were not introduced by the same agency. The sand probability plots, taken as a set, indicate an eolian origin. The rough symmetry of the mounds, and the lack of cross-bedding, argue against a migrating dune origin. On a variability plot (showing the variability of the means versus the variability of the standard deviations), one suite of samples fell clearly within the 'dune' number field, a second suite in the overlap area between 'dune' and 'beach', and a third suite, taken immediately adjacent to a creek bed, plotted in the overlap area between 'beach' and 'coastal plain stream'. The pebbles, of common Southern Appalachian types, are attributed to the activities of the inhabitants, perhaps children. The sand is thought to have been carried by the wind, perhaps from nearby river sand bars, or from areas burned either by lightning-set wildfires or as part of "slash-and-burn" agriculture. The mounds are thought to represent clearings (for huts), and hence good trapping devices for wind-borne sand.

  6. Seismic characterization of mound reservoirs using iterative modeling procedure

    SciTech Connect

    Rafison, B.J.; Stuart, C.J.

    1989-04-01

    A seismic stratigraphic analysis based on seismic attribute and stratigraphic modeling techniques was done on Paleocene submarine fan mounds in two North Sea blocks. The principal objective of these studies was to develop new interpretation concepts for resolving and mapping sandstone buildups and channel fills. Improved resolution and interpretation of these features should contribute to development of Paleocene exploration plays and reservoir characterization in these blocks.

  7. EG&G Mound Applied Technologies payroll system

    SciTech Connect

    Not Available

    1992-02-07

    EG&G Mound Applied Technologies, Inc., manages and operates the Mound Facility, Miamisburg, Ohio, under a cost-plus-award-fee contract administered by the Department of Energy`s Albuquerque Field Office. The contractor`s Payroll Department is responsible for prompt payment in the proper amount to all persons entitled to be paid, in compliance with applicable laws, regulations, and legal decisions. The objective was to determine whether controls were in place to avoid erroneous payroll payments. EG&G Mound Applied Technologies, Inc., did not have all the internal controls required by General Accounting Office Title 6, ``Pay, Leave, and Allowances.`` Specifically, they did not have computerized edits, separation of duties and responsibilities, and restricted access to payroll data files. This condition occurred because its managers were not aware of Title 6 requirements. As a result, the contractor could not assure the Department of Energy that payroll costs were processes accurately; and fraud, waste, or abuse of Department of Energy funds could go undetected. Our sample of 212 payroll transactions from a population of 66,000 in FY 1991 disclosed only two minor processing errors and no instances of fraud, waste or abuse.

  8. Implementation of linear bias corrections for calorimeters at Mound

    SciTech Connect

    Barnett, T.M.

    1993-12-31

    In the past, Mound has generally made relative bias corrections as part of the calibration of individual calorimeters. The correction made was the same over the entire operating range of the calorimeter, regardless of the magnitude of the range. Recently, an investigation was performed to check the relevancy of using linear bias corrections to calibrate the calorimeters. The bias is obtained by measuring calibrated plutonium and/or electrical heat standards over the operating range of the calorimeter. The bias correction is then calculated using a simple least squares fit (y = mx + b) of the bias in milliwatts over the operating range of the calorimeter in watts. The equation used is B{sub i} = B{sub 0} + (B{sub w} * W{sub m}), where B{sub i} is the bias at any given power in milliwatts, B{sub 0} is the intercept (absolute bias in milliwatts), B{sub w} is the slope (relative bias in milliwatts per watt), and W{sub m} is the measured power in watts. The results of the study showed a decrease in the random error of bias corrected data for most of the calorimeters which are operated over a large wattage range (greater than an order of magnitude). The linear technique for bias correction has been fully implemented at Mound and has been included in the Technical Manual, ``A Measurement Control Program for Radiometric Calorimeters at Mound`` (MD-21900).

  9. Intergenerational Panels at Centennial Events: Stimulating Discussion about Continuity and Change in the 4-H Program

    ERIC Educational Resources Information Center

    Kaplan, Matthew S.; Weikert, Ben; Scholl, Jan; Rushton, Mya

    2013-01-01

    This article introduces an intergenerational strategy for organizations planning centennial celebratory events. The methods and findings from the 4-H through the Generations session conducted at the joint 4-H Leadership Conference and 4-H Leaders Forum to celebrate the Pennsylvania 4-H Centennial are reported. Youth and adult participants shared…

  10. North Central Region 4-H Volunteers: Documenting Their Contributions and Volunteer Development

    ERIC Educational Resources Information Center

    Nippolt, Pamela Larson; Pleskac, Sue; Schwartz, Vicki; Swanson, Doug

    2012-01-01

    Documenting volunteer contributions strengthens Extension partnerships with volunteers. A team of North Central Region 4-H volunteer specialists collaborated to conduct a study of 4-H volunteer contributions and impacts related to working with youth within the 4-H program. Over three thousand (3,332) 4-H volunteers from throughout the 12-state…

  11. Using Cold-water Coral Mini-mounds as Analogue for Giant Mound Growth: Assessment of Environmental Drivers and Anthropogenic Impact

    NASA Astrophysics Data System (ADS)

    Collart, T.; Stewart, H. A.; Howell, K.; Bourillet, J. F.; Llave, E.; Blamart, D.; Mienis, F.; Van Rooij, D.

    2015-12-01

    Cold-water coral (CWC) reefs are formed by framework building scleratinians Lophelia pertusa and Madrepora oculata that baffle sediment and over time, have the potential to develop into large coral mounds of up to 300m high (e.g. Belgica Mound Province). The detailed mechanisms of initiation and build-up of such large CWC mounds are however not yet fully understood. It is therefore essential to study smaller mounds (often termed "mini-mounds") that can be interpreted as earlier growth stages that haven't had the time to coalesce and develop into larger mounds. The FWO Minimound project (2013-2017) aims to investigate CWC mini-mounds within the Bay of Biscay (European Margin) in order to determine the impact of: (1) palaeoceanographic changes related to glacial-interglacial climate change in the last 15 ka, (2) hydrocarbon seepage processes and (3) anthropogenic fishing activities on CWC habitats. The project targets three minimound provinces: the Ferrol Canyon (Cantabrian Margin), the Guilvinec Canyon (Armorican Margin) and the Explorer and Dangeard Canyons (Celtic Margin). These mini-mounds are fossil and occur at relative shallow depths on the interface between the Eastern North Atlantic Central Water (ENACW) and the Mediterranean Outflow Water (MOW). Contrastingly, most living CWC reefs in this region of the Atlantic, dwell in the deeper MOW depth range, relying on the density and dynamics of this water mass for their food supply. In order to investigate the initiation, growth and demise of CWC mini-mounds, 35m of USBL guided sediment cores were retrieved from the Explorer and Dangeard Interfluves. We present data of sedimentological, geochemical and palaeoceanographic analyses throughout the cores, coupled with high-resolution geophysical data. Preliminary results indicate that the mound base is associated with a strong shift in sedimentation regime potentially linked to climate driven palaeoceanographic changes of the MOW-ENACW interface.

  12. MVC Shell

    2008-06-03

    Provides the shell of a plugin based application environment that builds on MVC Framework to allow one to rapidly construct an application by using a collection of plugins. The MVC Shell is implemented in C# as a .NET 2.0 application that can then be used as a shell for building a plugin based application. The infrastructure allows for dynamically processing a specified collection of plugins in order to determine the functionality of the application, wheremore » all plugins operate within the context of the underlying MVC Framework environment.« less

  13. Tectonic control on sea-floor relief and the localization of Lower Mississippian Waulsortian mounds, New Mexico

    NASA Astrophysics Data System (ADS)

    Jeffery, David L.

    1997-11-01

    Lower Mississippian carbonate mud-rich bioherms, generally referred to as Waulsortian mounds, are commonly associated with low-paleolatitude carbonate ramp settings and have recently been recognized as important hydrocarbon reservoirs. The factors controlling localization of Waulsortian mounds have heretofore been poorly understood. Stratal relations exposed in the Alamogordo Member of the Lake Valley Formation in the Sacramento Mountains of New Mexico illustrate the effects of tectonism on carbonate sedimentation prior to, during, and after mound growth. They indicate that mound initiation and localization were strongly controlled by tectonically generated, intraramp, sea-floor topography. These observations bear strongly on understanding the controls on localization and growth of mud mounds in general. Stratal geometries observed in the underlying Andrecito Member indicate that this topography was modified by erosional and depositional processes prior to mound initiation. Mounds formed on the surfaces and margins of the intraramp topography as the result of aggradational, in situ accumulation of biogenic sediment. Differences in growth geometry of stratal units within individual mounds and differences between mounds are correlated with position of the mound on the ramp and the deformation occurring immediately prior to mound growth. It is probable that local tectonism continued during mound growth, and that local differences in the amount of relative uplift resulted in different amounts of space for growth of individual mounds, and thus determined differences in mound size and geometry.

  14. Nutrient dynamics and plant assemblages of Macrotermes falciger mounds in a savanna ecosystem

    NASA Astrophysics Data System (ADS)

    Muvengwi, Justice; Ndagurwa, Hilton G. T.; Nyenda, Tatenda; Mbiba, Monicah

    2016-10-01

    Termites through mound construction and foraging activities contribute significantly to carbon and nutrient fluxes in nutrient-poor savannas. Despite this recognition, studies on the influence of termite mounds on carbon and nitrogen dynamics in sub-tropical savannas are limited. In this regard, we examined soil nutrient concentrations, organic carbon and nitrogen mineralization in incubation experiments in mounds of Macrotermes falciger and surrounding soils of sub-tropical savanna, northeast Zimbabwe. We also addressed whether termite mounds altered the plant community and if effects were similar across functional groups i.e. grasses, forbs or woody plants. Mound soils had significantly higher silt and clay content, pH and concentrations of calcium (Ca), magnesium (Mg), potassium (K), organic carbon (C), ammonium (NH4+) and nitrate (NO3-) than surrounding soils, with marginal differences in phosphorus (P) and sodium (Na) between mounds and matrix soils. Nutrient enrichment increased by a factor ranging from 1.5 for C, 4.9 for Mg up to 10.3 for Ca. Although C mineralization, nitrification and nitrification fraction were similar between mounds and matrix soils, nitrogen mineralization was elevated on mounds relative to surrounding matrix soils. As a result, termite mounds supported unique plant communities rich and abundant in woody species but less diverse in grasses and forbs than the surrounding savanna matrix in response to mound-induced shifts in soil parameters specifically increased clay content, drainage and water availability, nutrient status and base cation (mainly Ca, Mg and Na) concentration. In conclusion, by altering soil properties such as texture, moisture content and nutrient status, termite mounds can alter the structure and composition of sub-tropical savanna plant communities, and these results are consistent with findings in other savanna systems suggesting that increase in soil clay content, nutrient status and associated changes in the plant

  15. Galapagos hydrothermal mounds: stratigraphy and chemistry revealed by deep-sea drilling.

    PubMed

    Natland, J H; Rosendahl, B; Hekinian, R; Dmitriev, Y; Fodor, R V; Goll, R M; Hoffert, M; Humphris, S E; Mattey, D P; Petersen, N; Roggenthen, W; Schrader, E L; Srivastava, R K; Warren, N

    1979-05-11

    The Galápagos mounds sea-floor hydrothermal system is at least 300,000 years old and once produced manganese-poor sediments, which nearly blanketed the area of the present mounds field. Present-day mound deposits are limited manganese-rich exposures, suggesting that the system has changed from rock-to water-dominated and has diminished in intensity with time.

  16. Biogeochemical study of termite mounds: a case study from Tummalapalle area of Andhra Pradesh, India.

    PubMed

    Arveti, Nagaraju; Reginald, S; Kumar, K Sunil; Harinath, V; Sreedhar, Y

    2012-04-01

    Termite mounds are abundant components of Tummalapalle area of uranium mineralization of Cuddapah District of Andhra Pradesh, India. The systematic research has been carried out on the application of termite mound sampling to mineral exploration in this region. The distribution of chemical elements Cu, Pb, Zn, Ni, Co, Cr, Li, Rb, Sr, Ba, and U were studied both in termite soils and adjacent surface soils. Uranium accumulations were noticed in seven termite mounds ranging from 10 to 36 ppm. A biogeochemical parameter called "Biological Absorption Coefficient" of the termite mounds indicated the termite affected soils contained huge amounts of chemical elements than the adjacent soils. PMID:21594643

  17. Variability of soil properties within large termite mounds in South Katanga, DRC - origins and applications.

    NASA Astrophysics Data System (ADS)

    Erens, Hans; Bazirake Mujinya, Basile; Boeckx, Pascal; Baert, Geert; Mees, Florias; Van Ranst, Eric

    2014-05-01

    The miombo woodlands of South Katanga (D.R. Congo) are characterized by a high spatial density of large conic termite mounds built by Macrotermes falciger (3 to 5 ha-1). With an average height of 5.05 m and diameter of 14.88 m, these are some of the largest biogenic structures in the world. The mound material is known to differ considerably from the surrounding Ferralsols. Specifically, mound material exhibits a finer texture, higher CEC and exchangeable basic cation content, lower organic matter content, and an accumulation of phosphorous, nitrate and secondary carbonates. However, as demonstrated by the present study, these soil properties are far from uniform within the volume of the mound. The termites' nesting and foraging activity, combined with pedogenic processes over extended periods of time, generates a wide range of physical, chemical, and biological conditions in different parts of the mound. Analysis of samples taken along a cross-section of a large active mound allowed generating contour plots, thus visualizing the variability of soil properties within the mound. The central columns of three other mounds were sampled to confirm apparent trends. The contour plots show that the mounds comprise four functional zones: (i) the active nest, found at the top; (ii) an accumulation zone , in more central parts of the mound; (iii) a dense inactive zone, surrounding the accumulation zone and consisting of accumulated erosion products from former active nests; and (iv) the outer mantle, characterized by intense varied biological activity and by a well-developed soil structure. Intermittent leaching plays a key role in explaining these patterns. Using radiocarbon dating, we found that some of these mounds are at least 2000 years old. Their current size and shape is likely the result of successive stages of erosion and rebuilding, in the course of alternating periods of mound abandonment and recolonization. Over time, termite foraging combined with limited leaching

  18. Biogeochemical study of termite mounds: a case study from Tummalapalle area of Andhra Pradesh, India.

    PubMed

    Arveti, Nagaraju; Reginald, S; Kumar, K Sunil; Harinath, V; Sreedhar, Y

    2012-04-01

    Termite mounds are abundant components of Tummalapalle area of uranium mineralization of Cuddapah District of Andhra Pradesh, India. The systematic research has been carried out on the application of termite mound sampling to mineral exploration in this region. The distribution of chemical elements Cu, Pb, Zn, Ni, Co, Cr, Li, Rb, Sr, Ba, and U were studied both in termite soils and adjacent surface soils. Uranium accumulations were noticed in seven termite mounds ranging from 10 to 36 ppm. A biogeochemical parameter called "Biological Absorption Coefficient" of the termite mounds indicated the termite affected soils contained huge amounts of chemical elements than the adjacent soils.

  19. Morphology and spatial patterns of Macrotermes mounds in the SE Katanga, D.R. Congo

    NASA Astrophysics Data System (ADS)

    Bazirake Mujinya, Basile; Mees, Florias; Erens, Hans; Baert, Geert; Van Ranst, Eric

    2015-04-01

    The spatial distribution patterns and morphological characteristics of Macrotermes falciger mounds were investigated in the Lubumbashi area, D.R. Congo. Examination of the spatial patterns of M. falciger mounds on high resolution satellite images reveals a mean areal number density of 2.9 ± 0.4 mounds ha-1. The high relative number of inactive mounds in the region, along with their regular distribution pattern, suggests that current termite mound occurrences are largely palaeostructures. Mound positions in the habitat are consistent with intraspecific competition rather than soil and substrate characteristics as controlling factor. Detailed morphological description of five deep termite-mound profiles (~7 m height/depth) shows that carbonate pedofeatures are present in all studied profiles, in contrast to the control soils. They mainly occur in the form of soft powdery masses, nodules and coatings on ped faces, all clearly pedogenic. Carbonate coatings occur mainly between 1 m above the soil surface and 1 m below that level in all mound profiles. Carbonate nodules do show a different distribution pattern at each site. Furthermore, when the studied profiles are considered to represent a toposequence, the stone layer occurs at greater depth in topographically low areas compared to crest and slope positions, which is mainly conditioned by erosion. The clay content of epigeal mounds increases from the summit to the toe slope, which can be largely related to differences in parent material. The Mn-Fe oxide concentrations occurring in all studied termite mound profiles reflect a seasonally high perched water table beneath the mound, which is more pronounced at the lower slope positions.

  20. Plant Mounds as Concentration and Stabilization Agents for Actinide Soil Contaminants in Nevada

    SciTech Connect

    D.S. Shafer; J. Gommes

    2009-02-03

    Plant mounds or blow-sand mounds are accumulations of soil particles and plant debris around the base of shrubs and are common features in deserts in the southwestern United States. An important factor in their formation is that shrubs create surface roughness that causes wind-suspended particles to be deposited and resist further suspension. Shrub mounds occur in some plant communities on the Nevada Test Site, the Nevada Test and Training Range (NTTR), and Tonopah Test Range (TTR), including areas of surface soil contamination from past nuclear testing. In the 1970s as part of early studies to understand properties of actinides in the environment, the Nevada Applied Ecology Group (NAEG) examined the accumulation of isotopes of Pu, 241Am, and U in plant mounds at safety experiment and storage-transportation test sites of nuclear devices. Although aerial concentrations of these contaminants were highest in the intershrub or desert pavement areas, the concentration in mounds were higher than in equal volumes of intershrub or desert pavement soil. The NAEG studies found the ratio of contaminant concentration of actinides in soil to be greater (1.6 to 2.0) in shrub mounds than in the surrounding areas of desert pavement. At Project 57 on the NTTR, 17 percent of the area was covered in mounds while at Clean Slate III on the TTR, 32 percent of the area was covered in mounds. If equivalent volumes of contaminated soil were compared between mounds and desert pavement areas at these sites, then the former might contain as much as 34 and 62 percent of the contaminant inventory, respectively. Not accounting for radionuclides associated with shrub mounds would cause the inventory of contaminants and potential exposure to be underestimated. In addition, preservation of shrub mounds could be important part of long-term stewardship if these sites are closed by fencing and posting with administrative controls.

  1. Characteristics and origin of Earth-mounds on the Eastern Snake River Plain, Idaho

    SciTech Connect

    Tullis, J.A.

    1995-09-01

    Earth-mounds are common features on the Eastern Snake River Plain, Idaho. The mounds are typically round or oval in plan view, <0.5 m in height, and from 8 to 14 m in diameter. They are found on flat and sloped surfaces, and appear less frequently in lowland areas. The mounds have formed on deposits of multiple sedimentary environments. Those studied included alluvial gravel terraces along the Big Lost River (late Pleistocene/early Holocene age), alluvial fan segments on the flanks of the Lost River Range (Bull Lake and Pinedale age equivalents), and loess/slopewash sediments overlying basalt flows. Backhoe trenches were dug to allow characterization of stratigraphy and soil development. Each mound has features unique to the depositional and pedogenic history of the site; however, there are common elements to all mounds that are linked to the history of mound formation. Each mound has a {open_quotes}floor{close_quotes} of a sediment or basement rock of significantly different hydraulic conductivity than the overlying sediment. These paleosurfaces are overlain by finer-grained sediments, typically loess or flood-overbank deposits. Mounds formed in environments where a sufficient thickness of fine-grained sediment held pore water in a system open to the migration to a freezing front. Heaving of the sediment occurred by the growth of ice lenses. Mound formation occurred at the end of the Late Pleistocene or early in the Holocene, and was followed by pedogenesis. Soils in the mounds were subsequently altered by bioturbation, buried by eolian deposition, and eroded by slopewash runoff. These secondary processes played a significant role in maintaining or increasing the mound/intermound relief.

  2. Controls on Pennsylvanian algal-mound distribution in mid-continent North America

    SciTech Connect

    Price, R.C.; Mitchell, J.C.; Ravn, R.L.

    1985-02-01

    Middle (Desmoinesian) and Upper (Missourian) Pennsylvanian phylloid algal-mound distribution in Missouri, Kansas, and Oklahoma is largely controlled by subtle sea-floor topography. Topographic highs served as loci favoring initiation and continued growth of complexes. Topographic highs controlling mound distribution are the shelf-edge rise in northeastern Oklahoma, the Bourbon arch in southeastern Kansas and the Mine Creek prodeltaic shale buildup in west-central Missouri. Outcrop studies document controls on development of these mounds and reveal the potential for development of stacked mounds. This will help exploration for these features in the subsurface to the west. The shelf-edge rise and Mine Creek prodeltaic shale buildup control the location of the Oologah algal-mound complex and an isolated algal mound in the Pawnee Limestone, respectively. These apparently were positive features only during Middle Pennsylvanian time. In contrast, the Bourbon arch apparently was controlled by basement faulting and remained high for a more-extended period of time. Both Middle and Upper Pennsylvanian algal mounds coincide with the geographic position of the Bourbon arch and result in a stacked-mound complex. Evidence suggesting that the Bourbon arch was a positive feature are (1) thinning of clastics over the feature and (2) change from anoxic, black, fissile, and phosphatic basinal shales to oxygenated, diversely fossiliferous gray shales over the arch.

  3. Plants in Your Ants: Using Ant Mounds to Test Basic Ecological Principles

    ERIC Educational Resources Information Center

    Zettler, Jennifer A.; Collier, Alexander; Leidersdorf, Bil; Sanou, Missa Patrick

    2010-01-01

    Urban students often have limited access to field sites for ecological studies. Ubiquitous ants and their mounds can be used to study and test ecology-based questions. We describe how soil collected from ant mounds can be used to investigate how biotic factors (ants) can affect abiotic factors in the soil that can, in turn, influence plant growth.

  4. An Exercise in Field Archaeology for the Gifted: Fake Mound, Genuine Scholarship.

    ERIC Educational Resources Information Center

    White, John R.

    1992-01-01

    At an archaeology camp program for gifted youngsters, students ages 11-16 built a mound with 5 archaeological levels, for future exploration. The "fake" mound ensured that student interest would be maintained, that students would learn about special problems and situations, and that irreplaceable bits of prehistory would not risk being damaged.…

  5. The ultraviolet photochemistry of diacetylene - Direct detection of primary products of the metastable C4H2* + C4H2 reaction

    NASA Technical Reports Server (NTRS)

    Bandy, Ralph E.; Lakshminarayan, Chitra; Frost, Rex K.; Zwier, Timothy S.

    1993-01-01

    The products of diacetylene's ultraviolet photochemistry over the 245-220 nm region were directly determined in experiments where C4H2 was excited within a small reaction tube attached to a pulsed nozzle. The products formed in the collisions of C4H2* with C4H2 were subsequently ionized by vacuum UV radiation (at 118 nm) in the ion source of a time-of-flight mass spectrometer. It was found that the reaction of C4H2* with C4H2 produces C6H2 (+C2H2), C8H2 (+2H,H2), and C8H3 (+H), confirming the results of Glicker and Okabe (1987). Under certain conditions, secondary products were observed. Mechanisms for the observed reactions are proposed.

  6. Expression analysis of kenaf cinnamate 4-hydroxylase (C4H) ortholog during developmental and stress responses

    Technology Transfer Automated Retrieval System (TEKTRAN)

    This study was conducted to clone and analyze the expression pattern of a C4H gene encoding cinnamate 4-hydroxylase from kenaf (Hibiscus cannabinus L.). A full-length C4H ortholog was cloned using degenerate primers and the RACE (rapid amplification of cDNA ends) method. The full-length C4H ortholog...

  7. Stewardship as a Means to Create Organizational Reform: A View into Minnesota 4-H Youth Development

    ERIC Educational Resources Information Center

    Skuza, Jennifer A.; Freeman, Dorothy M.; Bremseth, Tamara J.; Doering, Shirley A.; Quinlan, Robert B.; Morreim, Patricia A.; Deidrick, James C.

    2010-01-01

    Minnesota 4-H Youth Development (MN 4-H) used stewardship as a means to create organizational reform to address the public use of the 4-H name and emblem in terms of risk management, real estate and equipment, and finances. A task force implemented a participatory process with colleagues and stakeholders to build and implement the reform effort.…

  8. Relationship between Participation in 4-H and Community Leadership in Rural Montana

    ERIC Educational Resources Information Center

    Flynn, Allison; Frick, Martin; Steele, Douglas

    2010-01-01

    Studies on the impact of 4-H on former members generally use alumni as one cohort. In rural states, such as Montana, it is important to understand the impact of 4-H on alumni in these rural areas and the role 4-H plays in community involvement. The study reported here sought to determine the perception of current community leaders in rural Montana…

  9. Perceptions of Missouri 4-H Youth Development Personnel Regarding Interorganizational Cooperative Behavior

    ERIC Educational Resources Information Center

    McKim, Billy R.; Torres, Robert M.

    2011-01-01

    Perceptions of 4-H youth development personnel regarding interorganizational cooperation were studied between the perceived and desired levels of cooperative activities between 4-H youth development personnel and secondary agriculture teachers. Results indicated that 4-H youth development personnel wanted higher levels of coordinated efforts…

  10. Perceptions of Texas 4-H Livestock Ambassadors on Career Development, Higher Education, and Leadership Development

    ERIC Educational Resources Information Center

    Zanolini, William F.; Rayfield, John; Ripley, Jeff

    2013-01-01

    Selected 4-H youth participated in the Texas 4-H Livestock Ambassador program. Forty-five youth participated in the 3-day program delivered by university professors and staff, Texas AgriLife Extension faculty and industry representatives. An instrument was developed and administered to the Texas 4-H Livestock Ambassadors at the end of their first…

  11. Understanding the Knowledge and Use of Experiential Learning within Pennsylvania 4-H Clubs

    ERIC Educational Resources Information Center

    Bechtel, Robyn; Ewing, John C.; Threeton, Mark; Mincemoyer, Claudia

    2013-01-01

    Experiential learning is incorporated into the National 4-H curriculum. However, the state 4-H staff in Pennsylvania is unsure of the current knowledge and use of experiential learning within the local 4-H clubs. An online survey was distributed to Extension educators and volunteer leaders within Pennsylvania to assess the current knowledge and…

  12. Text to Speech: A 4-H Model of Accessibility and Inclusion

    ERIC Educational Resources Information Center

    Green, Jeremy W.

    2012-01-01

    4-H project manuals play an integral part in a youth's ability to achieve mastery in a specific project area. For youth who struggle with reading, written 4-H materials prove inadequate in addressing the needs of the learner. This article proposes a new delivery method of 4-H educational material designed to create a more inclusive and…

  13. Examination of Attitude and Interest Measures for 4-H Science Evaluation

    ERIC Educational Resources Information Center

    Lewis, Kendra M.; Worker, Steven M.

    2015-01-01

    Science education research has demonstrated the influence of affect on learning. The National 4-H Science Logic Model outlines outcomes from youth participation in 4-H science programs, which includes attitude and interest outcomes. The associated measure, the National 4-H Science Common Measure, assesses these attitude constructs and not other…

  14. Stakeholder participation in the Mound Plant environmental monitoring program

    SciTech Connect

    Bauer, L.R.

    1996-12-31

    The Mound Plant is a 306-acre U.S. Department of Energy (DOE) site located in southwest Ohio. Historically, the plant has researched, developed, and evaluated nuclear weapons components. This mission is nearing completion, and the site is on an accelerated schedule for environmental restoration. However, in support of remaining operations and decommissioning and decontamination projects, EG&G Mound continues to operate extensive networks of effluent and environmental monitors and samplers. The data generated by these networks are reported to stakeholders through formal and informal reports, newsletters, public meetings, press releases, and other mechanisms deemed appropriate. Among all of the Environmental Monitoring Program (EMP) results reported to stakeholders each year, regulators and area residents continue to demonstrate keen interest in the detection of radionuclides in the off-site environment. Technical exchanges on this subject have been held with the Ohio Environmental Protection Agency (OEPA), the Ohio Department of Health, and the Miamisburg Environmental Safety and Health Citizens Action Group. Exchanges held to date have focused on the water-sampling program; the air-sampling program will be studied subsequently.

  15. Lucky Mound field: A new Mississippian Sherwood shoreline field

    SciTech Connect

    Fisher, R.W. ); Hendricks, M.L. )

    1991-06-01

    Lucky Mound field produces oil and gas from the Sherwood interval of the Mississippian Mission Canyon Formation. Presently, eight wells are producing with development ongoing. Extensive coring, testing, logging, and petrographic evaluations throughout the field have allowed for detailed analysis of reservoir characteristics and paleoenvironmental interpretation. Sherwood shoreline fields typically produce from reservoir-quality packstones and grainstones trapped by a lateral facies changes into impermeable dolomite and anhydrite. At Lucky Mound, packstones, grainstones, and a productive dolomite facies all contribute to the producing interval. The productive dolomite facies is generally found in the upper portion of the Sherwood along the eastern margin of the field. Porosity as high as 22% and permeability values up to 16 md are present in the dolomite facies. These dolomites are the result of complete to partial replacement of micrite. In addition, the dolomitization process has enhanced intercrystalline and intraparticle porosity throughout the Sherwood interval. Pore types present include vuggy, intergranular, intraparticle, and intercrystalline. Pore occluding and replacive cements include fibrous calcite, prismatic calcite spar, baroque dolomite, anhydrite, celestite, pyrite, and chert. An understanding of carbonate depositional environments, diagenetic processes, Williston basin structural development, and Sherwood reservoir behavior is essential in the exploration for new Sherwood fields.

  16. Nonlinear dynamics of coiling, and mounding in viscoelastic jets

    NASA Astrophysics Data System (ADS)

    Majmudar, Trushant; Ober, Thomas; McKinley, Gareth

    2009-11-01

    Free surface continuous jets of non-Newtonian fluids, although relevant for many industrial processes like bottle filling, remain poorly understood in terms of fundamental fluid dynamics. Here we present a systematic study of the effect of viscoelasticity on the dynamics of continuous jets of worm-like micellar surfactant solutions of varying viscosities and elasticities, and model yield-stress fluids. We systematically vary the height of the drop and the flow rate in order to study the effects of varying geometric and kinematic parameters. We observe that for fluids with higher elastic relaxation times, folding is the preferred mode. In contrast, for low elasticity fluids we observe complex nonlinear dynamics consisting of coiling, folding, and irregular meandering as the height of the fall increases. Beyond this regime, the jet dynamics smoothly crosses over to exhibit the ``leaping shampoo" or the Kaye effect. Upon increasing the flow rate to very high values, the ``leaping shampoo" state disappears and is replaced by a pronounced mounding or ``heaping". A subsequent increase in the flow rate results in finger-like protrusions to emerge out of the mound and climb up towards the nozzle. This novel transition is currently under investigation and remains a theoretical challenge.

  17. Electromagnetic surveying of seafloor mounds in the northern Gulf of Mexico

    USGS Publications Warehouse

    Ellis, M.; Evans, R.L.; Hutchinson, D.; Hart, P.; Gardner, J.; Hagen, R.

    2008-01-01

    Seafloor controlled source electromagnetic data, probing the uppermost 30 m of seafloor sediments, have been collected with a towed magnetic dipole-dipole system across two seafloor mounds at approximately 1300 m water depth in the northern Gulf of Mexico. One of these mounds was the focus of??a recent gas hydrate research drilling program. Rather than the highly resistive response expected of massive gas hydrate within the confines of the mounds, the EM data are dominated by the effects of raised temperatures and pore fluid salinities that result in an electrically conductive seafloor. This structure suggests that fluid advection towards the seafloor is taking place beneath both mounds. Similar responses are seen at discrete locations away from the mounds in areas that might be associated with faults, further suggesting substantial shallow fluid circulation. Raised temperatures and salinities may inhibit gas hydrate formation at depth as has been suggested at other similar locations in the Gulf of Mexico. ?? 2008 Elsevier Ltd.

  18. The nature and origin of Mafic Mound in the South Pole-Aitken Basin

    NASA Astrophysics Data System (ADS)

    Moriarty, Daniel P.; Pieters, Carle M.

    2015-10-01

    "Mafic Mound" is a distinctive and enigmatic feature 75 km across and 1 km high near the center of the vast South Pole-Aitken Basin (SPA). Using several modern data sets, we characterize the composition, morphology, and gravity signature of the structure in order to assess its origin. Mafic Mound is found to exhibit a perched circular depression and a homogeneous high-Ca pyroxene-bearing composition. Several formation hypotheses based on known lunar processes are evaluated, including the possibilities that Mafic Mound represents (1) uplifted mantle, (2) SPA-derived impact melt, (3) a basalt-filled impact crater, or (4) a volcanic construct. Individually, these common processes cannot fully reproduce the properties of Mafic Mound. Instead, we propose a hybrid origin in which Mafic Mound is an edifice formed by magmatic processes induced by the formation and evolution of SPA. This form of nonmare volcanism has not previously been documented on the Moon.

  19. Kentucky and Tennessee. Mounds of potential pay in Ft. Payne reef trend

    SciTech Connect

    Bigelow, T.

    1983-06-01

    It is one of the hottest areas in Tennessee. Largely centered in Fentress, Scott and Morgan counties, the Ft. Payne reefs are a series of subsurface mounds, parallel to one another, that seemingly align in a northeast- southwest direction. The mounds are at depths of 1000 to 2500 ft. To the west near the Cincinnati Arch, the mounds are relatively shallow. Whereas to the southeast the mounds downdip at a rate of ca 50 ft/mile toward the Appalachian fold belt. Most activity to date has been in the shallower Ft. Payne. Production varies greatly, from 5 bopd/well to more than 900 bopd/well. There are 21 producing fields in the Ft. Payne, with total production in excess of 6 million bbl. The mounds are of Lower Mississippian age and are thought to have been deposited along a transgressive/regressive shoreline.

  20. COCARDE - a research platform for a new look to ancient mounds

    NASA Astrophysics Data System (ADS)

    Rüggeberg, Andres; Henriet, Jean-Pierre; Foubert, Anneleen; van Rooij, David; Samankassou, Elias; Dullo, Wolf-Christian; Spezzaferri, Silvia; Science Community, Cocarde

    2010-05-01

    Carbonate mounds are important contributors of life in different settings, from warm-water to cold-water environments, and throughout geological history. Research on modern carbonate mounds over the last years made a major contribution to our overall understanding of these particular sedimentary systems. By looking to the modern carbonate mound community, some fundamental questions could be addressed, until now not yet explored in fossil mound settings. The international network COCARDE (Cold-Water Carbonate Reservoir Systems in Deep Environment) is a platform for exploring new insights in cold- and warm-water carbonate mound research of recent and ancient mound systems (http://www.cocarde.eu). One aim of the COCARDE network is to bring scientific communities together, to study recent carbonate mounds in midslope environments in the present ocean, and to investigate fossil mounds spanning the whole Phanerozoic time. Scientific challenges on modern and ancient carbonate mound systems got already well defined during two dedicated workshops of the COCARDE network: 1) the ESF Magellan COCARDE Workshop in Fribourg, Switzerland, January 21-24, 2009, and 2) the ESF MiCROSYSTEMS - FWO COCARDE Flanders - ESF CHECREEF Workshop and Field Seminar, Oviedo, Spain, September 16-20, 2009. The wide spectrum of disciplines in geosciences and biology are summarized in the following five topics for the carbonate mound research: i) Palaeoenvironment; ii) The Microbial Filter; iii) Petrophysical Characterization; iv) Connectivity and Compartmentalization - the Fluid System; v) Advancing our Insight in Phanerozoic Reef Systems - the Slope Niche. One of the most important outcomes of these meetings was the identification of the need for combined research efforts on fossil and modern carbonate settings to provide the baseline reference standard for a better understanding of these exceptional systems and their potential as hydrocarbon reservoirs.

  1. Elimination of the Mound-Building Termite, Nasutitermes exitiosus (Isoptera: Termitidae) in South-Eastern Australia Using Bistrifluron Bait.

    PubMed

    Webb, Garry A; Mcclintock, Charles

    2015-12-01

    Bistrifluron, a benzoylphenylurea compound, was evaluated for efficacy against Nasutitermes exitiosus (Hill), a mound-building species in southern Australia. Bistrifluron bait (trade name Xterm) was delivered as containerized pellets inserted into plastic feeding stations implanted in the sides of mounds-60 g for bistrifluron bait-treated mounds and 120 g of blank bait for untreated mounds. Termites actively tunneled in the gaps between pellets and removed bait from the canisters. All five treated mounds were eventually eliminated, and all five untreated mounds remained active at the end of the trial. Four of the five treated mounds were considered dead and excavated after 26 wk, but there were earlier signs of mound distress-reduced repair of experimental casement damage and reduced activity in bait canisters by 22 wk and reduced internal mound temperature after 11 wk. One treated mound showed activity in the bait station right through until almost the end of the trial (47 wk), but excavation at 49 wk showed no further activity in the mound. The five untreated colonies removed on average 97% of blank bait offered, while the five treated colonies removed on average 39.1% of bait offered. There was a wide variation in temperature profiles of mounds (up to 15°C for both minimum and maximum internal temperatures), from the beginning of the trial and even before the effects of baiting were evident.

  2. Effigy mound sites as cultural landscapes: A geophysical spatial analysis of two Late Woodland sites in southeastern Wisconsin

    NASA Astrophysics Data System (ADS)

    Kaufmann, Kira E.

    This dissertation is a spatial analysis of a class of sacred sites known as Effigy Mounds during the Late Woodland period in southeast Wisconsin, circa A.D. 700--1100. Effigy Mounds are earthworks in the shape of animals, conical, linear, or geometric shapes. The research is focused on the upper Rock River Drainage in southern Wisconsin, a region where Effigy Mounds are very common. Although there are many theories concerning the meanings of Effigy Mounds, there is no cohesive description of Effigy Mounds as landscape elements and their function in the use of space by Late Woodland people. This research connects cultural and cognitive aspects of Native American cosmology with physical manifestations on the landscape. Effigy Mounds are examined from ideological and physical perspectives that are not mutually exclusive. Effigy Mounds are viewed as signifiers with multiple levels of function and meaning including sacred space, territorial markers, and mechanisms of social control and cohesion. Investigation at two Late Woodland Effigy Mound sites, Indian Mounds County Park in Jefferson County and Nitschke Mounds County Park in Dodge County, shows that landscape utilization varied significantly within and among Effigy Mound sites. An alternative model to understand Late Woodland Effigy Mound sites as ritual landscapes explores these features, their distribution across space, and the connection to internal site structures by synthesizing multidisciplinary data from historical ethnographic accounts, previous archaeological surveys, and new geophysical data. This multidisciplinary approach provides an example applicable to other landscape studies.

  3. Elimination of the Mound-Building Termite, Nasutitermes exitiosus (Isoptera: Termitidae) in South-Eastern Australia Using Bistrifluron Bait.

    PubMed

    Webb, Garry A; Mcclintock, Charles

    2015-12-01

    Bistrifluron, a benzoylphenylurea compound, was evaluated for efficacy against Nasutitermes exitiosus (Hill), a mound-building species in southern Australia. Bistrifluron bait (trade name Xterm) was delivered as containerized pellets inserted into plastic feeding stations implanted in the sides of mounds-60 g for bistrifluron bait-treated mounds and 120 g of blank bait for untreated mounds. Termites actively tunneled in the gaps between pellets and removed bait from the canisters. All five treated mounds were eventually eliminated, and all five untreated mounds remained active at the end of the trial. Four of the five treated mounds were considered dead and excavated after 26 wk, but there were earlier signs of mound distress-reduced repair of experimental casement damage and reduced activity in bait canisters by 22 wk and reduced internal mound temperature after 11 wk. One treated mound showed activity in the bait station right through until almost the end of the trial (47 wk), but excavation at 49 wk showed no further activity in the mound. The five untreated colonies removed on average 97% of blank bait offered, while the five treated colonies removed on average 39.1% of bait offered. There was a wide variation in temperature profiles of mounds (up to 15°C for both minimum and maximum internal temperatures), from the beginning of the trial and even before the effects of baiting were evident. PMID:26470378

  4. 77 FR 59615 - Decision To Evaluate a Petition To Designate a Class of Employees From the Mound Plant in...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-09-28

    ... HUMAN SERVICES Decision To Evaluate a Petition To Designate a Class of Employees From the Mound Plant in... evaluate a petition to designate a class of employees from the Mound Plant in Miamisburg, Ohio, to be... warranted by the evaluation, is as follows: Facility: Mound Plant. Location: Miamisburg, Ohio. Job...

  5. 75 FR 27783 - Decision To Evaluate a Petition To Designate a Class of Employees From the Mound Site in...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-05-18

    ... HUMAN SERVICES Decision To Evaluate a Petition To Designate a Class of Employees From the Mound Site in... employees from the Mound site in Miamisburg, Ohio, to be included in the Special Exposure Cohort under the...: Facility: Mound site. Location: Miamisburg, Ohio. Job Titles and/or Job Duties: All employees of...

  6. Vibration of Shells

    NASA Technical Reports Server (NTRS)

    Leissa, A. W.

    1973-01-01

    The vibrational characteristics and mechanical properties of shell structures are discussed. The subjects presented are: (1) fundamental equations of thin shell theory, (2) characteristics of thin circular cylindrical shells, (3) complicating effects in circular cylindrical shells, (4) noncircular cylindrical shell properties, (5) characteristics of spherical shells, and (6) solution of three-dimensional equations of motion for cylinders.

  7. Building Atoms Shell by Shell.

    ERIC Educational Resources Information Center

    Sussman, Beverly

    1993-01-01

    Describes an atom-building activity where students construct three-dimensional models of atoms using a styrofoam ball as the nucleus and pom-poms, gum drops, minimarshmallows, or other small items of two different colors to represent protons and neutrons attached. Rings of various sizes with pom-poms attached represent electron shells and…

  8. Shell worlds

    NASA Astrophysics Data System (ADS)

    Roy, Kenneth I.; Kennedy, Robert G., III; Fields, David E.

    2013-02-01

    The traditional concept of terraforming assumes ready availability of candidate planets with acceptable qualities: orbiting a star in its "Goldilocks zone", liquid water, enough mass, years longer than days, magnetic field, etc. But even stipulating affordable interstellar travel, we still might never find a good candidate elsewhere. Whatever we found likely would require centuries of heavy terraforming, just as Mars or Venus would here. Our increasing appreciation of the ubiquity of life suggests that any terra nova would already possess it. We would then face the dilemma of introducing alien life forms (us, our microbes) into another living world. Instead, we propose a novel method to create habitable environments for humanity by enclosing airless, sterile, otherwise useless planets, moons, and even large asteroids within engineered shells, which avoids the conundrum. These shells are subject to two opposing internal stresses: compression due to the primary's gravity, and tension from atmospheric pressure contained inside. By careful design, these two cancel each other resulting in zero net shell stress. Beneath the shell an Earth-like environment could be created similar in almost all respects to that of Home, except for gravity, regardless of the distance to the sun or other star. Englobing a small planet, moon, or even a dwarf planet like Ceres, would require astronomical amounts of material (quadrillions of tons) and energy, plus a great deal of time. It would be a quantum leap in difficulty over building Dyson Dots or industrializing our solar system, perhaps comparable to a mission across interstellar space with a living crew within their lifetime. But when accomplished, these constructs would be complete (albeit small) worlds, not merely large habitats. They could be stable across historic timescales, possibly geologic. Each would contain a full, self-sustaining ecology, which might evolve in curious directions over time. This has interesting implications

  9. Concordance in mate choice in female mound-building mice.

    PubMed

    Beigneux, Emilie; Féron, Christophe; Gouat, Patrick

    2012-03-01

    Females must evaluate male quality to perform mate choice. Since females generally base their selection on different male features, individual females may differ in their choice. In this study, we show that concordance between females in mate choice decisions may arise without any experimental maximization of a particular attractive trait. Choice tests were performed in mound-building mice, Mus spicilegus, a monogamous species. Body odours of two male donors were presented to 12 female subjects individually. To determine female choice, the same pair of males was presented three times to a female. Four different pairs of male body odours were used. Male donors, not related to females, were selected at random in our polymorphic breeding stock. Using this two-way choice design, female mice displayed a clear choice and had a similar preference for particular males.

  10. Three-dimensional potential flow over hills and oval mounds

    NASA Technical Reports Server (NTRS)

    Siegel, R.

    1976-01-01

    An analysis was made of the potential flow behavior for an initially uniform flow passing over a single axisymmetric hill, an oval mound, and a combination of two hills. Small perturbation theory was used, and the resulting Laplace equation for the perturbation velocity potential was solved by using either a product solution or a Green's function. The three dimensional solution is of interest in calculating the pressure distribution around obstacles, the flow of pollutants carried by the wind, and the augmentation of wind velocity for windmill siting. The augmentation in velocity at the top of a hill was found to be proportional to the hill height relative to a characteristic width dimension of the hill. An axisymmetric hill produced about 20 percent less velocity increase than a two dimensional ridge having the same cross-sectional profile.

  11. Microseismic Monitoring of the Mounds Drill Cuttings Injection Tests

    SciTech Connect

    Branagan, P.T.; Mahrer, K.D.; Moschovidis, Z.A.; Warpinski, N.R.; Wolhart, S.L.

    1999-01-25

    This paper describes the microseismic mapping of repeated injections of drill cuttings into two separate formations at a test site near Mounds, OK. Injections were performed in sandstone and shale formations at depths of 830 and 595 m, respectively. Typical injection disposal was simulated using multiple small-volume injections over a three-day period, with long shut-in periods interspersed between the injections. Microseismic monitoring was achieved using a 5-level array of wireline-run, triaxial- accelerometer receivers in a monitor well 76 m from the disposed well. Results of the mapped microseismic locations showed that the disposal domti W= generally aligns with the major horizontal stress with some variations in azimuth and that wide variations in height and length growth occurred with continued injections. These experiments show that the cuttings injection process cm be adequately monitored from a downhole, wireline-run receiver array, thus providing process control and environmental assurance.

  12. Composition of seismically identified satellite mounds surrounding Greater Aneth field, southeast Utah

    SciTech Connect

    Eby, D.E. ); Groen, W.G.; Johnson, J.F. )

    1993-08-01

    Five different types of satellite mounds have been encountered during drilling and extensive coring of approximately 40 high-resolution CDP (common depth point) seismic anomalies in the Desert Creek interval of the Pennsylvanian (Desmoinesian) Paradox Formation around the periphery of Greater Aneth field. The composition and diagenetic modification of these mound types directly affect the quality of porosity and permeability within each satellite buildup. The mound types and their principal characteristics are (1) crinoid-sponge limestone with wackestone to packstone fabrics; (2) coralline algal boundstones that are slightly dolomitized; (3) bryozoan-dominated lime boundstones with no significant dissolution porosity; (4) phylloid algal bafflestones with extensive dissolution and some dolomitization occasionally overlain by dolomitized stromatolitic/thrombolitic boundstones; and (5) stacked bioclastic grainstones with extensive dissolution and complete dolomitization. Controls on the development of each mound type appear to be a function of water depth and prevailing water energy. Mound types 1 and 2 typically have low porosity, whereas type 3 preserved primary porosity. Types 4 and 5 commonly exhibit extensive porosity and permeability modification through freshwater dissolution and early dolomitization. Up to five cycles of buildup growth can occur within the Desert Creek satellite mounds. Mound composition types will recur or change to another growth type depending upon local water depth and energy conditions. Calibration of seismic amplitude variations can be used in imaging reservoir size and porosity variation.

  13. Ground-squirrel mounds and related patterned ground along the San Andreas Fault in Central California

    USGS Publications Warehouse

    Wallace, Robert E.

    1991-01-01

    Extensive areas of mound topography and related patterned ground, apparently derived from the mounds of the California Ground Squirrel (Spermophilus beecheyi beecheyi), are in central California.  The relation of patterned ground to the San Andreas fault west of Bakersfield may provide insight into the timing of deformation along the fault as well as the history of ground squirrels.  Mound topography appears to have evolved through several stages from scattered mounds currently being constructed on newly deposited alluvial surfaces, to saturation of areas by mounds, followed by coalescence, elongation and lineation of the mounds.  Elongation, coalescence and modification of the mounds has been primarily by wind, but to a lesser extent by drainage and solifluction.  A time frame including ages of 4,000, 10,500, 29,000, and 73,000 years BP is derived by relating the patterns to slip on the San Andreas fault.  Further relating of the patterns to faulting, tilting, and warping may illuminate details of the rates and history of deformation.  Similarly, relating the patterns to the history of ground squirrel activity may help answer such problems as rates of dispersal and limits on population density.

  14. Overview of surface studies on high energy materials at Mound

    SciTech Connect

    Moddeman, W.E.; Collins, L.W.; Wang, P.S.; Haws, L.D.; Wittberg, T.N.

    1980-01-01

    Since 1975 Mound has been examining the surface structure of high energy materials and the interaction of these materials with various metal containers. The high energy materials that have been studied include: the pyrotechnic TiH/sub x//KClO/sub 4/, the Al/Cu/sub 2/O machinable thermite, the PETN, HMX and RDX explosives, and two plastic bonded explosives (PBX). Aluminum and alloys of Fe, Ni and Cr have been used as the containment materials. Two aims in this research are: (1) the elucidation of the mechanism of pyrotechnic ignition and (2) the compatibility of high energy materials with their surroundings. New information has been generated by coupling Auger electron spectroscopy (AES) and x-ray photoelectron spectroscopy (XPS) with thermal data. In particular, AES and XPS studies on the pyrotechnic materials and on thermites have shown the mechanism of ignition to be nearly independent of the type of oxidizer present but directly related to surface chemistry of the fuels. In studies on the two PBX's, PBX-9407 and LX-16, it was concluded that the Exon coating on 9407 was complete and greater than or equal to 100A; whereas in LX-16, the coating was < 100A or even incomplete. AES and scanning Auger have been used to characterize the surface composition and oxide thickness for an iron-nickel alloy and showed the thicker oxides to have the least propensity for atmospheric hydrocarbon adsorption. Data are presented and illustrations made which highlight this new approach to studying ignition and compatibility of high energy materials. Finally, the salient features of the X-SAM-800 purchased by Mound are discussed in light of future studies on high energy materials.

  15. Surgical anatomy of the midcheek and malar mounds.

    PubMed

    Mendelson, Bryan C; Muzaffar, Arshad R; Adams, William P

    2002-09-01

    The anatomy of the midcheek has not been satisfactorily described to adequately explain midcheek aging and malar mounds, nor has it suggested a logical approach to their correction or provided sufficient detail for safe surgery in this area. This cadaver study, which was complemented by many operative dissections, located a missing link: a glide plane space overlying the body of the zygoma. The space functions to allow mobility of the orbicularis oculi, where it overlies the zygoma and the origins of the elevator muscles to the upper lip. The space is a cleft between the sub-orbicularis oculi fat and the preperiosteal fat and is lined by a fine membrane. The anatomic boundaries are clearly defined by retaining ligaments, which correlate with the triangularity of the space. Several anatomic features provide the functional characteristics of the prezygomatic space, including the (1) absence of direct attachments between the orbicularis in the roof to the floor, (2) more rigid inferior boundary formed by the zygomatic ligaments, and (3) more mobile upper ligamentous boundary formed by the orbicularis retaining ligament (separating from the preseptal space of the lower lid). These components determine the characteristic aging changes that occur in this region and explain much about malar mounds. An appreciation of this anatomy has several surgical implications. The prezygomatic space is a junction area that can be approached from the temple, lower lid, and cheek. The zygomatic branches of the facial nerve to the orbicularis do not cross the space; rather, they course in the walls and in the sub-orbicularis fat within the roof of the space.

  16. [Flora Differentiation among Local Ecotopes in the Transzonal Study of Forest-Steppe and Steppe Mounds].

    PubMed

    Lisetskii, F N; Sudnik-Wojcikowska, B; Moysiyenko, I I

    2016-01-01

    Flora similarity was assessed using complete floristic lists of five ecotopes in each of four mounds along the transect from meadow steppes to desert steppes. It was found that the circumapical similitude of floras is more significant than the expositional similitude. Soil analysis in separate ecotopes showed that regular changes in the biogeochemical features are manifested along the topographic gradient and under the effect of the insolation exposure of slopes in local (mound) ecosystems. It was noted that the slopes are characterized by the most abundant steppe vegetation classes in the phytosociological spectrum of mound ecotopes.

  17. Decay of silicon mounds: scaling laws and description with continuum step parameters

    PubMed

    Ichimiya; Hayashi; Williams; Einstein; Uwaha; Watanabe

    2000-04-17

    The decay of mounds about a dozen layers high on the Si(111)-(7x7) surface has been measured quantitatively by scanning tunneling microscopy and compared with analytic predictions for the power-law dependence on time predicted for a step-mediated decay mechanism. Conformably, we find an exponent 1/4 associated with the (3D) decay of the mound height and exponent 1/3 associated with the (2D) decay of top-layer islands. Using parameters from a continuum step model, we capture the essence of the kinetics. Qualitative features distinguish these mounds from multilayer islands found on metals.

  18. [Flora Differentiation among Local Ecotopes in the Transzonal Study of Forest-Steppe and Steppe Mounds].

    PubMed

    Lisetskii, F N; Sudnik-Wojcikowska, B; Moysiyenko, I I

    2016-01-01

    Flora similarity was assessed using complete floristic lists of five ecotopes in each of four mounds along the transect from meadow steppes to desert steppes. It was found that the circumapical similitude of floras is more significant than the expositional similitude. Soil analysis in separate ecotopes showed that regular changes in the biogeochemical features are manifested along the topographic gradient and under the effect of the insolation exposure of slopes in local (mound) ecosystems. It was noted that the slopes are characterized by the most abundant steppe vegetation classes in the phytosociological spectrum of mound ecotopes. PMID:27396182

  19. Indigenous utilization of termite mounds and their sustainability in a rice growing village of the central plain of Laos

    PubMed Central

    2011-01-01

    Background The objective of this study was to investigate the indigenous utilization of termite mounds and termites in a rain-fed rice growing village in the central plain of Laos, where rice production is low and varies year-to-year, and to assess the possibility of sustainable termite mound utilization in the future. This research was carried out from 2007 to 2009. Methods The termites were collected from their mounds and surrounding areas and identified. Twenty villagers were interviewed on their use of termites and their mounds in the village. Sixty-three mounds were measured to determine their dimensions in early March, early July and middle to late November, 2009. Results Eleven species of Termitidae were recorded during the survey period. It was found that the villagers use termite mounds as fertilizer for growing rice, vegetable beds and charcoal kilns. The villagers collected termites for food and as feed for breeding fish. Over the survey period, 81% of the mounds surveyed increased in volume; however, the volume was estimated to decrease by 0.114 m3 mound-1 year-1 on average due to several mounds being completely cut out. Conclusion It was concluded that current mound utilization by villagers is not sustainable. To ensure sustainable termite utilization in the future, studies should be conducted to enhance factors that promote mound restoration by termites. Furthermore, it will be necessary to improve mound conservation methods used by the villagers after changes in the soil mass of mounds in paddy fields and forests has been measured accurately. The socio-economic factors that affect mound utilization should also be studied. PMID:21849087

  20. 4-H PetPALS Juvenile Diversion Program Supports At-Risk Youth and Seniors

    ERIC Educational Resources Information Center

    Goble, Connie L.; Miller, Lucinda B.

    2014-01-01

    The 4-H PetPALS Juvenile Diversion Program provides a partnership opportunity with Extension and the juvenile court system to positively impact lives of at-risk youth. At-risk youth are taught by 4-H PetPALS adult volunteer leaders and 4-H PetPALS members to value and respect the human-animal bond, as well as to understand and empathize with…

  1. AB INITIO CHARACTERIZATION OF C{sup -}{sub 4}, C{sub 4}H, AND C{sub 4}H{sup -}

    SciTech Connect

    Senent, M. L.

    2010-01-10

    Using state-of-the-art theoretical methods, we investigate the stable isomers of C{sup -}{sub 4}, C{sub 4}H and C{sub 4}H{sup -}. Three of them are relevant for astrophysics and astrochemistry. These computations are performed using highly correlated ab initio methods and the aug-cc-pVXZ (X = T,Q) basis sets. In addition to the linear isomers, we predict the existence of several cyclic and branched forms for these molecules. For all the molecular species of interest here, sets of spectroscopic parameters are determined with perturbation theory, which compare quite well with experiment. For l - C{sub 4}H{sup -}(X {sup 1}SIGMA{sup +}), the quartic force field is computed at the coupled cluster level of theory. This force field is derived from full nine-dimensional potential energy surface generated close to the equilibrium geometry of this anion. Finally, we treat the thermochemistry of the hydrogen attachment and the electron attachment reactions that may lead to the formation of the C{sub 4}H{sup -} from either C{sup -}{sub 4} or C{sub 4}H.

  2. Assessment of the AWC TRUclean process for use on Mound soils and sediments

    SciTech Connect

    Rogers, D.R.

    1989-03-23

    The AWC TRUclean System has been proposed as a method to reduce the volume of LSA waste during D&D excavation of Pu-238 contaminated soils on the Mound Site and Pu-238 contaminated sediments in the Miami-Erie Canal. Following test runs with Mound soil, AWC suggested that the TRUclean Process could reduce the amount of LSA waste by greater than 90% if a machine could be built and used to process the Mound soil. The cost savings which could potentially be realized by assuming this magnitude of volume reduction were thought to be significant on large projects. These preliminary results suggested that a review of the TRUclean Process and the 1987 test results should be performed to determine a course of action. The AWC TRUclean Process and the test data have been evaluated and the potential effectiveness of the process determined for use on Mound soils and/or on the sediments in the Miami-Erie Canal.

  3. Buried cold-water coral mounds and contourite deposits in the Atlantic Moroccan Coral Province

    NASA Astrophysics Data System (ADS)

    Vandorpe, Thomas; Hebbeln, Dierk; Wienberg, Claudia; Van den Berghe, Michèle; Van Rooij, David

    2016-04-01

    The Atlantic Moroccan Coral Province (AMCP) is situated in the southern Gulf of Cadiz roughly between 34° 50'N to 35°35'N and 6°30'W to 7°15'W. The region displays tectonic (ridges and both large transverse as well as small normal and reverse faults) as well as sedimentological features (drifts deposits and sediment waves). Eleven mud volcanoes are present in the northern part of the region as well (Vandorpe et al., in press). Besides the presence of many surfacing small cold-water coral mounds, hundreds to thousands of mounds were discovered in the subsurface through 2D seismic parasound and sparker seismic profiles. Over 90% of the mounds are situated at water depths between 600 and 1000 meters and most of them occur in clusters. The cold-water coral mounds are rather small in this region (compared to the 100 m high mounds in the Belgica Province in the Porcupine basin (Huvenne et al., 2003)). Their widths vary between 20 and 200 m with a modus around 60 m, while their heights vary between 2 and 40 m with a modus around 10 m. Moreover, ten horizons at which mound growth initiated can be distinguished, compared to the single mound growth event observed in the Porcupine Basin (Huvenne et al., 2003). This points towards rapidly changing environmental conditions in the AMCP which were sometimes favourable for initiation and growth of cold-water coral mounds. These favourable periods rapidly switched to periods when corals were not able to settle and the mounds could get buried. Mound growth initiates mostly at elevated places, e.g. tectonic ridges, outcropping bedrock or even previous cold-water coral mounds. Elevated places deflect bottom currents and increase the amount of food particles and sediments delivered to the corals, but also create sedimentological features such as contourites. The contourite deposits in the region greatly depend on the slope of the topography against which they are present (Vandorpe et al., in press). When mounds were able to reach a

  4. Sedimentary Mounds on Mars: Tracing Present-day Formation Processes into the Past

    NASA Technical Reports Server (NTRS)

    Niles, P. B.; Michalski, J.; Edwards, C. S.

    2014-01-01

    High resolution photography and spectroscopy of the martian surface (MOC, HiRISE) from orbit has revolutionized our view of Mars with one and revealed spectacular views of finely layered sedimentary materials throughout the globe [1]. Some of these sedimentary deposits are 'mound' shaped and lie inside of craters (Fig 1). Crater mound deposits are found throughout the equatorial region, as well as ice-rich deposits found in craters in the north and south polar region [2-4]. Despite their wide geographical extent and varying volatile content, the 'mound' deposits have a large number of geomorphic and structural similarities that suggest they formed via equivalent processes. Thus, modern depositional processes of ice and dust can serve as an invaluable analog for interpreting the genesis of ancient sedimentary mound deposits.

  5. Integrated research on the Pen Duick cold-water coral mounds: the MiCROSYSTEMS approach

    NASA Astrophysics Data System (ADS)

    van Rooij, David; de Mol, Lies; Blamart, Dominique; Mienis, Furu; Wehrmann, Laura M.; Barbieri, Roberto; Maignien, Lois; Templer, Stefanie P.; de Haas, Henk; Henriet, Jean-Pierre

    2010-05-01

    The ESF EuroDIVERSITY MiCROSYSTEMS project aimed to turn the cold-water coral (CWC) mounds on the Pen Duick Escarpment (PDE) in the Gulf of Cadiz into a natural laboratory, exploring this highly complex biotope and to characterize its biodiversity. A common point of discussion with all other CWC mound provinces, surpassing its broad range of regional and morphological variability, concerns the driving forces regarding the initiation of these complex deep-water systems. Both oceanographic and geological processes have been proposed to play a significant role in the mound nucleation, growth and decline. During IODP Expedition 307, the importance of biogeochemical processes was already elucidated. Here, we present the preliminary results of the MD169 campaign as an integrated case study of three PDE CWC mounds: Alpha, Beta and Gamma mounds. Although cold-water corals are a common feature on the adjacent cliffs, mud volcanoes and seafloor, no actual living reef has been observed during the many ROV surveys. This multidisciplinary study aims to present a comprehensive and holistic view on the local dynamic geological and oceanographic environment. Coring data suggests (past or present) methane seepage near the Pen Duick Escarpment. Several sources and pathways are proposed, among which a stratigraphic migration through uplifted Miocene series underneath PDE. Its dominant morphology has influenced the local hydrodynamics within the course of the Pliocene, as documented by the emplacement of a sediment drift. Predominantly during post-Middle Pleistocene glacial episodes, favourable conditions were present for mound growth. An additional advantage for CWC mound nucleation near the top of PDE is offered through seepage-related carbonate crusts which might offer elevated colonization positions. Present-day seabed observations also suggested a possible important role of open coral rubble frameworks in the mound building process. These graveyards not only act as sediment trap

  6. Some characteristics of soils on the man made mounds in the Harran Plain of Turkey.

    PubMed

    Irmak, Seyyid; Surucu, Abdülkadir

    2007-12-15

    Morphological, chemical and some mineralogical characteristics of five soils, were researched to understand the genesis of soils on the man made mounds in the Harran Plain, in the Southeast Anatolia Region of Turkey. Five soil profiles developed on the man made mounds in the arid region. Time and climate have affected soil formation. Also, parent material has influenced the chemistry of soils. The parent material of man made mounds were carried from around soils in the Harran Plain by men in years ago. The parent materials of around soils are calcareous parent materials and alluvium materials. Pedon 1 was described on the Konuklu man made mounds the northeast of the study area and Pedon 5 was described on the Küplüce man made mounds the southeast of the study area. According to the place of man made mounds were ordered from north to south as following: Pedon 1, Pedon 2, Pedon 3, Pedon 4 and Pedon 5. The old of Konuklu mounds is approximately 5000-6000 years. The old of Sultantepe and Koruklu mounds are approximately 6000 years. Pedon 4 which was described on the old Harran city remnants have the youngest soils of study area. The Harran mounds was made in 1258 A.I. by Mongolians. Mongolians destroyed the Harran City and made the Harran mounds. The most important pedogenic processes is carbonate leaching and accumulation in the pedon 5 on the Küplüce man made mounds. The CaCO3 content of Pedon 5 may be attributed to eolian addition from Syria. Total Al2O3 contents of soils higher than total Fe2O3 content. According to the degree of soil formation the profiles were ordered as following: Pedon 3 > Pedon 5 > Pedon 2 > Pedon 1 > Pedon 4. The results of total elements analysis were used to determine the beta leaching factor according to Jenny. The leaching factor were determined as < 1 in the Pedon 1 (0.99), Pedon 2 (0.97), Pedon 3 (0.74) and Pedon 5 (0.92). The leaching factor were determined as >1 in the Pedon 4(1.13).

  7. Archaeological mounds as analogs of engineered covers for waste disposal sites: Literature review and progress report. [Appendix contains bibliography and data on archaeological mounds

    SciTech Connect

    Chatters, J C; Gard, H A

    1991-09-01

    Closure caps for low-level radioactive waste disposal facilities are typically designed as layered earthen structures, the composition of which is intended to prevent the infiltration of water and the intrusion of the public into waste forms. Federal regulations require that closure caps perform these functions well enough that minimum exposure guidelines will be met for at least 500 years. Short-term experimentation cannot mimic the conditions that will affect closure caps on the scale of centuries, and therefore cannot provide data on the performance of cap designs over long periods of time. Archaeological mounds hundreds to thousands of years old which are closely analogous to closure caps in form, construction details, and intent can be studied to obtain the necessary understanding of design performance. Pacific Northwest Laboratory conducted a review and analysis of archaeological literature on ancient human-made mounds to determine the quality and potential applicability of this information base to assessments of waste facility design performance. A bibliography of over 200 English-language references was assembled on mound structures from the Americas, Europe, and Asia. A sample of these texts was read for data on variables including environmental and geographic setting, condition, design features, construction. Detailed information was obtained on all variables except those relating to physical and hydrological characteristics of the mound matrix, which few texts presented. It is concluded that an extensive amount of literature and data are available on structures closely analogous to closure caps and that this information is a valuable source of data on the long-term performance of mounded structures. Additional study is recommended, including an expanded analysis of design features reported in the literature and field studies of the physical and hydraulic characteristics of different mound designs. 23 refs., 10 figs., 12 tabs.

  8. An exhumed Palaeozoic underwater scenery: the Visean mud mounds of the eastern Anti-Atlas (Morocco)

    NASA Astrophysics Data System (ADS)

    Wendt, Jobst; Kaufmann, Bernd; Belka, Zdzislaw

    2001-12-01

    About one hundred carbonate mud mounds, covering an area of 440 km 2 in the eastern Anti-Atlas of Morocco, constitute one of the largest mound agglomerations known so far from Lower Carboniferous settings. They occur within a 4000-m-thick succession of shales with intercalated bedded limestones, sandstones, and siltstones. According to conodont and goniatite biostratigraphy, mound formation started in the early Gnathodus texanus Zone and terminated during the G. bilineatus Zone of the Visean stage. Individual mounds are a few metres to 30 m high, have base diameters of up to 300 m and are concentrated in several parallel, WNW-ESE running belts. From their lithology and facies relationships, four types of mounds can be distinguished: (1) massive crinoidal wacke- or packstones without stromatactis; (2) massive crinoidal wacke- or packstones with rare stromatactis; (3) similar to (2), but allochthonous; and (4) biodetrital (skeletal) grainstone mounds. While carbonate deposition in types (1) to (3) was probably triggered by microbial precipitation, type (4) is the result of a predominantly mechanical accumulation of skeletal debris. Biota in the four types comprise a great variety of invertebrates, among which crinoids, sponges, and bryozoans are most common. Diagenesis of the mound carbonates was dominated by recrystallization of micritic matrix and organic remains and late burial cementation. Oxygen and carbon isotope data of brachiopod and crinoid ossicles, matrix, and early marine cements plot in a large field and do not allow definite conclusions about the composition of the ambient seawater. Microbial activity and the absence or scarcity of green algae, colonial corals and coralline sponges suggest deposition of the mounds in moderate water depth close to the lower limit of the photic zone.

  9. Isotope Biogeochemistry of Sulfur in a Cold-Water Carbonate Mound (IODP Site 1317)

    NASA Astrophysics Data System (ADS)

    Ferdelman, T. G.; Boettcher, M. E.

    2007-12-01

    To establish a depositional model for cold-water carbonate mounds, Challenger Mound and adjacent continental slope sites were drilled during IODP Expedition 307 in May 2005. Although a role for methane seepage and subsequent anaerobic oxidation was discounted both as a hard-round substrate for mound initiation and as a principal source of carbonate within the mound succession, interstitial water profiles of sulfate, alkalinity, Mg, and Sr indicated a tight coupling between carbonate diagenesis and mircrobial sulfate reduction. The reaction of sulfide with siliciclastic iron-bearing minerals to form pyrite was proposed to account for enhanced diagenetic carbonate precipitation (Ferdelman et al., 2006; Proc. IODP, vol. 307; doi:10.2204/iodp.proc.307.2006). To characterize these geomicrobial sulfur transformations in the carbonate mound sediments, the inorganic and stable isotope geochemical compositions of pore water sulfate and solid phase reduced sulfur compounds were performed. Acid-volatile sulfur (AVS) and pyrite del 34S compositions were usually similar and exhibited an increasing trend of from -40 per mil near surface to -20 per mil at the mound base at 132 mbsf. However, several excursions to more 34S sulfur enriched pyrite to values >0 per mil were observed in the deeper sections of the mound sequence. These excursions may be linked transitory changes in the depth of the methane-sulfate transition zone during mound build-up. The oxygen isotopic composition of residual dissolved sulfate indicates intracellular isotope exchange processes within the cells of SRBs, leading to increasing equilibration between extracellular pore water and sulfate.

  10. Bacterial density and community structure associated with aggregate size fractions of soil-feeding termite mounds.

    PubMed

    Fall, S; Nazaret, S; Chotte, J L; Brauman, A

    2004-08-01

    The building and foraging activities of termites are known to modify soil characteristics such as the heterogeneity. In tropical savannas the impact of the activity of soil-feeding termites ( Cubitermes niokoloensis) has been shown to affect the properties of the soil at the aggregate level by creating new soil microenvironments (aggregate size fractions) [13]. These changes were investigated in greater depth by looking at the microbial density (AODC) and the genetic structure (automated rRNA intergenic spacer analysis: ARISA) of the communities in the different aggregate size fractions (i.e., coarse sand, fine sand, coarse silt, fine silt, and dispersible clays) separated from compartments (internal and external wall) of three Cubitermes niokoloensis mounds. The bacterial density of the mounds was significantly higher (1.5 to 3 times) than that of the surrounding soil. Within the aggregate size fractions, the termite building activity resulted in a significant increase in bacterial density within the coarser fractions (>20 mum). Multivariate analysis of the ARISA profiles revealed that the bacterial genetic structures of unfractionated soil and soil aggregate size fractions of the three mounds was noticeably different from the savanna soil used as a reference. Moreover, the microbial community associated with the different microenvironments in the three termite mounds revealed three distinct clusters formed by the aggregate size fractions of each mound. Except for the 2-20 mum fraction, these results suggest that the mound microbial genetic structure is more dependent upon microbial pool affiliation (the termite mound) than on the soil location (aggregate size fraction). The causes of the specificity of the microbial community structure of termite mound aggregate size fractions are discussed.

  11. Monolayer growth modes of Re and Nb on 4H -SiC(0001) and 4H-SiC(0001¯)

    NASA Astrophysics Data System (ADS)

    Bryant, K. W.; Bozack, M. J.

    2005-01-01

    Auger electron spectroscopy (AES) and secondary electron emission have been used to specify the room temperature monolayer adsorption characteristics of Re and Nb on the basal, polar surfaces of 4H -SiC. Measurement of the secondary electron emission current relates the absorbed crystal current to the change in AES peak-to-peak signal intensities for both substrate and adsorbate. For the 4H-SiC(0001) Si-face surface, both metals grow by formation of a single monolayer followed by growth of simultaneous monolayers. For the 4H -SiC(0001¯) C-face surface, both metals grow layer by layer (Frank-van der Merwe). Measurements of the coefficient of attenuation, inelastic mean free path, and coverage versus Auger intensities are also reported.

  12. The Surales, Self-Organized Earth-Mound Landscapes Made by Earthworms in a Seasonal Tropical Wetland.

    PubMed

    Zangerlé, Anne; Renard, Delphine; Iriarte, José; Suarez Jimenez, Luz Elena; Adame Montoya, Kisay Lorena; Juilleret, Jérôme; McKey, Doyle

    2016-01-01

    The formation, functioning and emergent properties of patterned landscapes have recently drawn increased attention, notably in semi-arid ecosystems. We describe and analyze a set of similarly spectacular landforms in seasonal tropical wetlands. Surales landscapes, comprised of densely packed, regularly spaced mounds, cover large areas of the Orinoco Llanos. Although descriptions of surales date back to the 1940's, their ecology is virtually unknown. From data on soil physical and chemical properties, soil macrofauna, vegetation and aerial imagery, we provide evidence of the spatial extent of surales and how they form and develop. Mounds are largely comprised of earthworm casts. Recognizable, recently produced casts account for up to one-half of total soil mass. Locally, mounds are relatively constant in size, but vary greatly across sites in diameter (0.5-5 m) and height (from 0.3 m to over 2 m). This variation appears to reflect a chronosequence of surales formation and growth. Mound shape (round to labyrinth) varies across elevational gradients. Mounds are initiated when large earthworms feed in shallowly flooded soils, depositing casts that form 'towers' above water level. Using permanent galleries, each earthworm returns repeatedly to the same spot to deposit casts and to respire. Over time, the tower becomes a mound. Because each earthworm has a restricted foraging radius, there is net movement of soil to the mound from the surrounding area. As the mound grows, its basin thus becomes deeper, making initiation of a new mound nearby more difficult. When mounds already initiated are situated close together, the basin between them is filled and mounds coalesce to form larger composite mounds. Over time, this process produces mounds up to 5 m in diameter and 2 m tall. Our results suggest that one earthworm species drives self-organizing processes that produce keystone structures determining ecosystem functioning and development. PMID:27168157

  13. The Surales, Self-Organized Earth-Mound Landscapes Made by Earthworms in a Seasonal Tropical Wetland.

    PubMed

    Zangerlé, Anne; Renard, Delphine; Iriarte, José; Suarez Jimenez, Luz Elena; Adame Montoya, Kisay Lorena; Juilleret, Jérôme; McKey, Doyle

    2016-01-01

    The formation, functioning and emergent properties of patterned landscapes have recently drawn increased attention, notably in semi-arid ecosystems. We describe and analyze a set of similarly spectacular landforms in seasonal tropical wetlands. Surales landscapes, comprised of densely packed, regularly spaced mounds, cover large areas of the Orinoco Llanos. Although descriptions of surales date back to the 1940's, their ecology is virtually unknown. From data on soil physical and chemical properties, soil macrofauna, vegetation and aerial imagery, we provide evidence of the spatial extent of surales and how they form and develop. Mounds are largely comprised of earthworm casts. Recognizable, recently produced casts account for up to one-half of total soil mass. Locally, mounds are relatively constant in size, but vary greatly across sites in diameter (0.5-5 m) and height (from 0.3 m to over 2 m). This variation appears to reflect a chronosequence of surales formation and growth. Mound shape (round to labyrinth) varies across elevational gradients. Mounds are initiated when large earthworms feed in shallowly flooded soils, depositing casts that form 'towers' above water level. Using permanent galleries, each earthworm returns repeatedly to the same spot to deposit casts and to respire. Over time, the tower becomes a mound. Because each earthworm has a restricted foraging radius, there is net movement of soil to the mound from the surrounding area. As the mound grows, its basin thus becomes deeper, making initiation of a new mound nearby more difficult. When mounds already initiated are situated close together, the basin between them is filled and mounds coalesce to form larger composite mounds. Over time, this process produces mounds up to 5 m in diameter and 2 m tall. Our results suggest that one earthworm species drives self-organizing processes that produce keystone structures determining ecosystem functioning and development.

  14. The Surales, Self-Organized Earth-Mound Landscapes Made by Earthworms in a Seasonal Tropical Wetland

    PubMed Central

    Iriarte, José; Suarez Jimenez, Luz Elena; Adame Montoya, Kisay Lorena; Juilleret, Jérôme; McKey, Doyle

    2016-01-01

    The formation, functioning and emergent properties of patterned landscapes have recently drawn increased attention, notably in semi-arid ecosystems. We describe and analyze a set of similarly spectacular landforms in seasonal tropical wetlands. Surales landscapes, comprised of densely packed, regularly spaced mounds, cover large areas of the Orinoco Llanos. Although descriptions of surales date back to the 1940’s, their ecology is virtually unknown. From data on soil physical and chemical properties, soil macrofauna, vegetation and aerial imagery, we provide evidence of the spatial extent of surales and how they form and develop. Mounds are largely comprised of earthworm casts. Recognizable, recently produced casts account for up to one-half of total soil mass. Locally, mounds are relatively constant in size, but vary greatly across sites in diameter (0.5–5 m) and height (from 0.3 m to over 2 m). This variation appears to reflect a chronosequence of surales formation and growth. Mound shape (round to labyrinth) varies across elevational gradients. Mounds are initiated when large earthworms feed in shallowly flooded soils, depositing casts that form ‘towers’ above water level. Using permanent galleries, each earthworm returns repeatedly to the same spot to deposit casts and to respire. Over time, the tower becomes a mound. Because each earthworm has a restricted foraging radius, there is net movement of soil to the mound from the surrounding area. As the mound grows, its basin thus becomes deeper, making initiation of a new mound nearby more difficult. When mounds already initiated are situated close together, the basin between them is filled and mounds coalesce to form larger composite mounds. Over time, this process produces mounds up to 5 m in diameter and 2 m tall. Our results suggest that one earthworm species drives self-organizing processes that produce keystone structures determining ecosystem functioning and development. PMID:27168157

  15. 7 CFR 8.9 - Use in 4-H fund raising.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ...-raising programs using the 4-H Name or Emblem may be carried out for specific educational purposes. Such... Research, Education, and Extension Service, United States Department of Agriculture, or a designee, if the fund-raising program is multi-State or Nationwide. (b) When used to promote 4-H educational...

  16. The 4-H Debate Project: Getting Adults and Children Involved in Communication.

    ERIC Educational Resources Information Center

    Atwater, Deborah F.

    Intended to enhance adult leadership skills, the 4-H Debate Project, developed by the 4-H Communication Committee of Delaware County (Pennsylvania), was designed to (1) increase the members' knowledge of library skills through research, (2) make them aware of current issues, (3) help them to become better public speakers and communicators, (4)…

  17. Factors Related to the Developmental Experiences of Youth Serving as 4-H Camp Counselors

    ERIC Educational Resources Information Center

    Carter, David N.; Kotrlik, Joe W.

    2008-01-01

    The purpose of this study was to investigate the developmental experiences of high-school-aged 4-H youth volunteering as counselors at Louisiana 4-H summer camps. A total of 288 counselors from 10 different camping sessions participated in the study. The Youth Experiences Survey 2.0 and the Developmental Experience Survey measured the personal…

  18. The Challenges Associated with Change in 4-H/Youth Development.

    ERIC Educational Resources Information Center

    McKee, Renee K.; Talbert, B. Allen; Barkman, Susan J.

    2002-01-01

    A survey of 97 Indiana 4-H/youth development educators and interviews with staff and volunteer board members indicated that volunteers believe in core 4-H values, recommend reaching more and different youth, and believe that the rural image inhibits progress. Staff interactions with volunteers, lack of parental involvement, group organization and…

  19. Bringing Carnaval Drum and Dance Traditions into 4-H Programming for Latino Youth

    ERIC Educational Resources Information Center

    Conklin-Ginop, Evelyn; Braverman, Marc T.; Caruso, Robyn; Bone, Dennis

    2011-01-01

    4-H Bloco Drum and Dance is an afterschool program that teaches adolescents drumming, dancing, and theater arts in the rich traditions of Brazilian Carnaval. Teens learn to express themselves in a variety of modalities and perform at community events. The program was developed by a community coalition that included 4-H, other youth programs, and…

  20. Cinnamate 4-Hydroxylase (C4H) genes from Leucaena leucocephala: a pulp yielding leguminous tree.

    PubMed

    Kumar, Santosh; Omer, Sumita; Patel, Krunal; Khan, Bashir M

    2013-02-01

    Leucaena leucocephala is a leguminous tree species accounting for one-fourth of raw material supplied to paper and pulp industry in India. Cinnamate 4-Hydroxylase (C4H, EC 1.14.13.11) is the second gene of phenylpropanoid pathway and a member of cytochrome P450 family. There is currently intense interest to alter or modify lignin content of L. leucocephala. Three highly similar C4H alleles of LlC4H1 gene were isolated and characterized. The alleles shared more than 98 % sequence identity at amino acid level to each other. Binding of partial promoter of another C4H gene LlC4H2, to varying amounts of crude nuclear proteins isolated from leaf and stem tissues of L. leucocephala formed two loose and one strong complex, respectively, suggesting that the abundance of proteins that bind with the partial C4H promoter is higher in stem tissue than in leaf tissue. Quantitative Real Time PCR study suggested that among tissues of same age, root tissues had highest level of C4H transcripts. Maximum transcript level was observed in 30 day old root tissue. Among the tissues investigated, C4H activity was highest in 60 day old root tissues. Tissue specific quantitative comparison of lignin from developing seedling stage to 1 year old tree stage indicated that Klason lignin increased in tissues with age. PMID:23070917

  1. 4-H and Forestry Afterschool Clubs: A Collaboration to Foster Stewardship Attitudes and Behaviors in Youth

    ERIC Educational Resources Information Center

    Gupta, Angela S.; Grant, Samantha; Strauss, Andrea Lorek

    2012-01-01

    The University of Minnesota Extension's 4-H and Forestry Afterschool program combined the 4-H structure and various forestry curricula to foster positive attitudes towards the environment and stewardship-related behaviors as these may serve as precursors to later choices that benefit the environment. Evaluation of third through fifth grade…

  2. The Effects of Age, Gender, and 4-H Involvement on Life Skill Development

    ERIC Educational Resources Information Center

    Haas, Bruce E.; Mincemoyer, Claudia C.; Perkins, Daniel F.

    2015-01-01

    The study reported here examined the effects of age, gender, and 4-H involvement in clubs on life skill development of youth ages eight to 18 over a 12-month period. Regression analyses found age, gender, and 4-H involvement significantly influenced life skill development. Results found that females have higher levels of competencies in life…

  3. 4-H and Tech Ed Partnership Gets Students Geeked about STEM

    ERIC Educational Resources Information Center

    Ivey, Debra; Quam, Greg

    2009-01-01

    This article discusses the 4-H Gateway Academies specifically designed to enhance science, technology, engineering, and math (STEM) skills and knowledge in middle school youth. The innovative summer day camps partnered Project Lead the Way--trained teachers with county 4-H staff from University of Wisconsin-Extension (UW-Extension) Cooperative…

  4. Birds in Your Backyard. 4-H Leaders Guide. L-5-17.

    ERIC Educational Resources Information Center

    Hawkes, Janet E.; Held Phillips, Diane

    This pocket folder of instructional materials is designed to introduce youth aged 9 to 12 to ornithology, the study of birds. The package includes a 4-H member's guide and a Leader's guide. The illustrated 4-H member's guide contains information about attracting and feeding birds. It also includes activities for cooking for birds, making bird…

  5. Acquisition, Custody, and Storage of Firearms Used in 4-H Shooting Sports Programs

    ERIC Educational Resources Information Center

    White, David J.; Smith, Jedediah D.

    2014-01-01

    Shooting sports has been a 4-H program offering since the 1930's. Tragic events related to the use of firearms as weapons have caused public and private entities to evaluate and consider the appropriateness of youth access to and usage of firearms. 4-H educators have the primary responsibility for managing the risk associated with shooting…

  6. 4-H and School-Age Care: A Great Combination! Point of View.

    ERIC Educational Resources Information Center

    Vandenbergh, Barbara D.

    1999-01-01

    Discusses the positive relationship between 4-H programs and school-age care programs, advocating the use of 4-H programs as a model for care, or as a source of care, caregiver training, or curriculum. Notes the role of the Cooperative Extension System in training and supporting school-age care providers. (JPB)

  7. Food Challenge: Serving Up 4-H to Non-Traditional Audiences

    ERIC Educational Resources Information Center

    Dodd, Sara; Follmer-Reece, Holly E.; Kostina-Ritchey, Erin; Reyna, Roxanna

    2015-01-01

    This article describes a novel approach for introducing 4-H to non-traditional/diverse audiences using 4-H Food Challenge. Set in a low SES and minority-serving rural school, Food Challenge was presented during the school day to all 7th grade students, with almost half voluntarily participating in an after-school club component. Program design…

  8. College Transition Study Shows 4-H Helps Youth Prepare for and Succeed in College

    ERIC Educational Resources Information Center

    Ratkos, Judy; Knollenberg, Lauren

    2015-01-01

    Many young adults enter college without the knowledge and skills necessary to succeed. The purpose of the study reported here was to determine if 4-H helps develop life skills needed for the transition to college and overall college success. An online survey was sent to college-attending 4-H alumni and a comparison group, with a final sample size…

  9. 4-H Youth Development: The Past, the Present, and the Future

    ERIC Educational Resources Information Center

    Borden, Lynne M.; Perkins, Daniel F.; Hawkey, Kyle

    2014-01-01

    The 4-H Program within Cooperative Extension is more than 100 years old. As we celebrate 100 years of Cooperative Extension, the foundation built by the 4-H Program serves as grounds to meet the needs of today's youth. The diversity of the youth who participate continues to grow, families continue to become less traditional, potential…

  10. 4-H Healthy Living Programs with Impact: A National Environmental Scan

    ERIC Educational Resources Information Center

    Downey, Laura H.; Peterson, Donna J.; LeMenestrel, Suzanne; Leatherman, JoAnne; Lang, James

    2014-01-01

    The 4-H youth development program of the nation's 109 land-grant universities and the Cooperative Extension System is one of the largest youth development organization in the United States serving approximately six million youth. The 4-H Healthy Living initiative began in 2008 to promote achievement of optimal physical, social, and emotional…

  11. Characteristics and Perceptions of 4-H Participants: Gender and Age Differences across Adolescence

    ERIC Educational Resources Information Center

    Bartoszuk, Karin; Randall, Brandy A.

    2011-01-01

    The study reported here examined 367 adolescent 4-H participants in terms of demographic, psychological, behavioral, and relational characteristics, as well as their perceptions and experiences in 4-H. Overall, participants scored high on all outcome variables except having a diverse population in their club. Older participants were more…

  12. Fitting the Framework: The STEM Institute and the 4-H Essential Elements

    ERIC Educational Resources Information Center

    Sallee, Jeff; Peek, Gina G.

    2014-01-01

    Extension and 4-H youth development programs are addressing a shortage of scientists, engineers, and other related professionals by promoting science, technology, engineering, and math (STEM). This case study illustrates how the Oklahoma 4-H Youth Development program trained youth-adult teams to design and implement STEM projects. The STEM…

  13. Global 4-H Network: Laying the Groundwork for Global Extension Opportunities

    ERIC Educational Resources Information Center

    Major, Jennifer; Miller, Rhonda

    2012-01-01

    A descriptive study examining 4-H programs in Africa, Asia, and Europe was conducted to provide understanding and direction in the establishment of a Global 4-H Network. Information regarding structure, organizational support, funding, and programming areas was gathered. Programs varied greatly by country, and many partnered with other 4-H…

  14. Zonation of Microbial Communities by a Hydrothermal Mound in the Atlantis II Deep (the Red Sea)

    PubMed Central

    Wang, Yong; Li, Jiang Tao; He, Li Sheng; Yang, Bo; Gao, Zhao Ming; Cao, Hui Luo; Batang, Zenon; Al-Suwailem, Abdulaziz; Qian, Pei-Yuan

    2015-01-01

    In deep-sea geothermal rift zones, the dispersal of hydrothermal fluids of moderately-high temperatures typically forms subseafloor mounds. Major mineral components of the crust covering the mound are barite and metal sulfides. As a result of the continental rifting along the Red Sea, metalliferous sediments accumulate on the seafloor of the Atlantis II Deep. In the present study, a barite crust was identified in a sediment core from the Atlantis II Deep, indicating the formation of a hydrothermal mound at the sampling site. Here, we examined how such a dense barite crust could affect the local environment and the distribution of microbial inhabitants. Our results demonstrate distinctive features of mineral components and microbial communities in the sediment layers separated by the barite crust. Within the mound, archaea accounted for 65% of the community. In contrast, the sediments above the barite boundary were overwhelmed by bacteria. The composition of microbial communities under the mound was similar to that in the sediments of the nearby Discovery Deep and marine cold seeps. This work reveals the zonation of microbial communities after the formation of the hydrothermal mound in the subsurface sediments of the rift basin. PMID:26485717

  15. Oil reservoirs in grainstone aprons around Bryozoan Mounds, Upper Harrodsburg Limestone, Mississippian, Illinois Basin

    SciTech Connect

    Jobe, H.; Saller, A.

    1995-06-01

    Several oil pools have been discovered recently in the upper Harrodsburg Limestone (middle Mississippian) of the Illinois basin. A depositional model for bryozoan mound complexes has allowed more successful exploration and development in this play. In the Johnsonville area of Wayne County, Illinois, three lithofacies are dominant in the upper Harrodsburg: (1) bryozoan boundstones, (2) bryozoan grainstones, and (3) fossiliferous wackestones. Bryozoan boundstones occur as discontinuous mounds and have low porosity. Although bryozoan boundstones are not the main reservoir lithofacies, they are important because they influenced the distribution of bryozoan grainstones and existing structure. Bryozoan grainstones have intergranular porosity and are the main reservoir rock. Bryozoan fragments derived from bryozoan boundstone mounds were concentrated in grainstones around the mounds. Fossiliferous wackestones are not porous and form vertical and lateral seals for upper Harrodsburg grainstones. Fossiliferous wackestones were deposited in deeper water adjacent to bryozoan grainstone aprons, and above grainstones and boundstones after the mounds were drowned. Upper Harrodsburg oil reservoirs occur where grainstone aprons are structurally high. The Harrodsburg is a good example of a carbonate mound system where boundstone cores are not porous, but adjacent grainstones are porous. Primary recovery in these upper Harrodsburg reservoirs is improved by strong pressure support from an aquifer in the lower Harrodsburg. Unfortunately, oil production is commonly decreased by water encroaching from that underlying aquifer.

  16. Textural variation within Great Salt Lake algal mounds: Chapter 8.5 in Stromatolites

    USGS Publications Warehouse

    1976-01-01

    This chapter discusses textural variation within the Great Salt Lake algal mounds. Great Salt Lake algal mounds contain: (1) a framework of non-skeletal, algally induced aragonite precipitates; (2) internal sediment; and (3) inorganic cement. These three elements create a variety of laminated, poorly laminated, and unlaminated internal textures. Interior framework precipitates bear little resemblance to the present living film of the mound surface. Internal texture of the mounds is believed to be largely relict and to have resulted from precipitation by algae different than those presently living at the surface. The most probable cause of local extinction of the algal flora is change in brine salinity. Precipitated blue-green algal structures in ancient rocks may indicate other than normal marine salinity and near shore sedimentation. Extreme variation of internal texture reflects extreme environmental variability typical of closed basin lakes. Recognition of mounds similar to those in the Great Salt Lake can be a first step toward recognition of ancient hyper-saline lake deposits, if such an interpretation is substantiated by consideration of the entire depositional milieu of precipitated algal mounds.

  17. Regional Mapping and Spectral Analysis of Mounds in Acidalia Planitia, Mars

    NASA Technical Reports Server (NTRS)

    Amador, E. S.; Allen, Carlton; Oehler, D. Z.

    2010-01-01

    Acidalia Planitia is a approx.3000 km diameter planum located in the northern plains of Mars. It is believed to be a sedimentary basin containing an accumulation of sediments brought by Hesperian outflow channels that drained the Highlands. A large number of high-albedo mounds have been identified across this basin [1-2] and understanding the process that formed them should help us understand the history of this region. Farrand et al. [2] showed that the mounds are dark in THEMIS (Thermal Emission Imaging System) nighttime IR (infrared) image data. This implies that the mounds have a lower thermal inertia than the surrounding plains (Fig. 1), suggesting that the material of the mounds is fine-grained or unconsolidated. Farrand et al. [2] also reviewed potential analogs for the mounds and concluded that a combination of mud volcanoes with evaporites around geysers or springs is most consistent with all the data. We have built on this work by creating regional maps of the features and analyzing CRISM (Compact Reconnaissance Imaging Spectrometer for Mars) data to see if there are mineralogical differences between the mounds and surrounding plains.

  18. Zonation of Microbial Communities by a Hydrothermal Mound in the Atlantis II Deep (the Red Sea).

    PubMed

    Wang, Yong; Li, Jiang Tao; He, Li Sheng; Yang, Bo; Gao, Zhao Ming; Cao, Hui Luo; Batang, Zenon; Al-Suwailem, Abdulaziz; Qian, Pei-Yuan

    2015-01-01

    In deep-sea geothermal rift zones, the dispersal of hydrothermal fluids of moderately-high temperatures typically forms subseafloor mounds. Major mineral components of the crust covering the mound are barite and metal sulfides. As a result of the continental rifting along the Red Sea, metalliferous sediments accumulate on the seafloor of the Atlantis II Deep. In the present study, a barite crust was identified in a sediment core from the Atlantis II Deep, indicating the formation of a hydrothermal mound at the sampling site. Here, we examined how such a dense barite crust could affect the local environment and the distribution of microbial inhabitants. Our results demonstrate distinctive features of mineral components and microbial communities in the sediment layers separated by the barite crust. Within the mound, archaea accounted for 65% of the community. In contrast, the sediments above the barite boundary were overwhelmed by bacteria. The composition of microbial communities under the mound was similar to that in the sediments of the nearby Discovery Deep and marine cold seeps. This work reveals the zonation of microbial communities after the formation of the hydrothermal mound in the subsurface sediments of the rift basin. PMID:26485717

  19. The Role of Benthic Currents and Sediment Transport On Deep-water Coral Mound Morphology and Growth: Examples From The Belgica and Moira Mounds, Eastern Porcupine Seabight, NE Atlantic

    NASA Astrophysics Data System (ADS)

    Wheeler, A.; Kozachenko, M.; Olu-Le Roy, K.

    Deep-water corals and associated carbonate mound build-ups are extensive along the European continental margin coincident with areas of strong benthic current activity and, often, regions of active sand transport. Although as yet unsubstantiated links to hydrocarbon seepage may play a defining role in the generation of carbonate mounds, the growth of mounds is strongly influenced by benthic current activity. Furthermore, the morphology of mounds, both in terms of their overall shape and surface morpho- logical features, is strongly dictated by the benthic-currents. Giant carbonate mounds, e.g. the Thérèse Mound, Belgica Mound province, eastern Porcupine Seabight, NE Atlantic, show upstream growth (through biological and sed- imentary accretion) with downstream scour and sediment starvation influencing their overall morphology. The surface morphological details of these giant mounds show distinct relationships to sediment waves that have become colonised and stabilised by coral and associated communities. Once colonised, the sandwave surface-morphology is mimic by biological growth with corals preferential growing on wave crests, taking advantage of stronger current and nutrient flux, to form coral banks. Furthermore, erosion of carbonate mounds by strong current activity exposes suitable hard substrates for further coral colonisation. Paradoxically therefore, mound erosion stimulates further coral growth illustrating another benthic-current control on mound growth. The Moira Mounds in the Belgica Mound Province, Porcupine Seabight are small coral-colonised mound features (tens of metres across and a few metres high) that represent an early stage of mound development and much younger then their giant carbonate mound counterparts. These features occur in areas of active sand transport, on rippled sand sheets and the upstream margins of sediment wave fields. Once coral colonies gained a SfootingT in these areas, coral colonies trap sand and build posi- & cedil; 1

  20. Simple method for the growth of 4H silicon carbide on silicon substrate

    NASA Astrophysics Data System (ADS)

    Asghar, M.; Shahid, M. Y.; Iqbal, F.; Fatima, K.; Nawaz, Muhammad Asif; Arbi, H. M.; Tsu, R.

    2016-03-01

    In this study we report thermal evaporation technique as a simple method for the growth of 4H silicon carbide on p-type silicon substrate. A mixture of Si and C60 powder of high purity (99.99%) was evaporated from molybdenum boat. The as grown film was characterized by XRD, FTIR, UV-Vis Spectrophotometer and Hall Measurements. The XRD pattern displayed four peaks at 2Θ angles 28.550, 32.700, 36.100 and 58.900 related to Si (1 1 1), 4H-SiC (1 0 0), 4H-SiC (1 1 1) and 4H-SiC (2 2 2), respectively. FTIR, UV-Vis spectrophotometer and electrical properties further strengthened the 4H-SiC growth.

  1. Ultra high voltage MOS controlled 4H-SiC power switching devices

    NASA Astrophysics Data System (ADS)

    Ryu, S.; Capell, C.; Van Brunt, E.; Jonas, C.; O'Loughlin, M.; Clayton, J.; Lam, K.; Pala, V.; Hull, B.; Lemma, Y.; Lichtenwalner, D.; Zhang, Q. J.; Richmond, J.; Butler, P.; Grider, D.; Casady, J.; Allen, S.; Palmour, J.; Hinojosa, M.; Tipton, C. W.; Scozzie, C.

    2015-08-01

    Ultra high voltage (UHV, >15 kV) 4H-silicon carbide (SiC) power devices have the potential to significantly improve the system performance, reliability, and cost of energy conversion systems by providing reduced part count, simplified circuit topology, and reduced switching losses. In this paper, we compare the two MOS based UHV 4H-SiC power switching devices; 15 kV 4H-SiC MOSFETs and 15 kV 4H-SiC n-IGBTs. The 15 kV 4H-SiC MOSFET shows a specific on-resistance of 204 mΩ cm2 at 25 °C, which increased to 570 mΩ cm2 at 150 °C. The 15 kV 4H-SiC MOSFET provides low, temperature-independent, switching losses which makes the device more attractive for applications that require higher switching frequencies. The 15 kV 4H-SiC n-IGBT shows a significantly lower forward voltage drop (VF), along with reasonable switching performance, which make it a very attractive device for high voltage applications with lower switching frequency requirements. An electrothermal analysis showed that the 15 kV 4H-SiC n-IGBT outperforms the 15 kV 4H-SiC MOSFET for applications with switching frequencies of less than 5 kHz. It was also shown that the use of a carrier storage layer (CSL) can significantly improve the conduction performance of the 15 kV 4H-SiC n-IGBTs.

  2. Cost estimate for muddy water palladium production facility at Mound

    SciTech Connect

    McAdams, R.K.

    1988-11-30

    An economic feasibility study was performed on the ''Muddy Water'' low-chlorine content palladium powder production process developed by Mound. The total capital investment and total operating costs (dollars per gram) were determined for production batch sizes of 1--10 kg in 1-kg increments. The report includes a brief description of the Muddy Water process, the process flow diagram, and material balances for the various production batch sizes. Two types of facilities were evaluated--one for production of new, ''virgin'' palladium powder, and one for recycling existing material. The total capital investment for virgin facilities ranged from $600,000 --$1.3 million for production batch sizes of 1--10 kg, respectively. The range for recycle facilities was $1--$2.3 million. The total operating cost for 100% acceptable powder production in the virgin facilities ranged from $23 per gram for a 1-kg production batch size to $8 per gram for a 10-kg batch size. Similarly for recycle facilities, the total operating cost ranged from $34 per gram to $5 per gram. The total operating cost versus product acceptability (ranging from 50%--100% acceptability) was also evaluated for both virgin and recycle facilities. Because production sizes studied vary widely and because scale-up factors are unknown for batch sizes greater than 1 kg, all costs are ''order-of-magnitude'' estimates. All costs reported are in 1987 dollars.

  3. Earth-mounded concrete bunker PLAP technical approach

    SciTech Connect

    Eng, R.

    1989-11-01

    Under the US DOE Prototype License Application Project (PLAP), Ebasco Services Incorporated was commissioned to develop a preliminary design of the Earth-Mounded Concrete Bunker (EMCB) concept for low-level radioactive waste (LLW) disposal. The EMCB disposal concept is of great interest because it represents the only engineered LLW disposal technology currently in use in the commercial sector. By definition, the EMCB disposal structure is located partially below grade and partially above grade. The concrete bunker is an engineered structure designed to be structurally stable for the prerequisite time horizon. The basic design parameters of the disposal facility were stipulated by US DOE, a northeast site location, representative waste, 30 year operational life, and a 250,000 ft{sup 3}/year disposal capacity. The design was developed to satisfy only US NRC Part 61 disposal requirements, not individual state requirements that may go beyond Part 61 requirements. The technical safety analysis of the preliminary design was documented according to the format specifications of NUREG-1199, to the extent practicable with quite limited resources.

  4. Bryan Mound SPR cavern 113 remedial leach stage 1 analysis.

    SciTech Connect

    Rudeen, David Keith; Weber, Paula D.; Lord, David L.

    2013-08-01

    The U.S. Strategic Petroleum Reserve implemented the first stage of a leach plan in 2011-2012 to expand storage volume in the existing Bryan Mound 113 cavern from a starting volume of 7.4 million barrels (MMB) to its design volume of 11.2 MMB. The first stage was terminated several months earlier than expected in August, 2012, as the upper section of the leach zone expanded outward more quickly than design. The oil-brine interface was then re-positioned with the intent to resume leaching in the second stage configuration. This report evaluates the as-built configuration of the cavern at the end of the first stage, and recommends changes to the second stage plan in order to accommodate for the variance between the first stage plan and the as-built cavern. SANSMIC leach code simulations are presented and compared with sonar surveys in order to aid in the analysis and offer projections of likely outcomes from the revised plan for the second stage leach.

  5. Origin Hypotheses for Kilometer-Scale Mounds on Dwarf Planet Ceres

    NASA Astrophysics Data System (ADS)

    Sizemore, Hanna G.; Platz, Thomas; Schmidt, Britney E.; Scully, Jennifer E. C.; Russell, Christopher T.; Mest, Scott C.; Crown, David A.; Sykes, Mark V.; Hughson, Kynan H. G.; Chilton, Heather T.; Williams, David A.; Pieters, Carle M.; Marchi, Simone; Travis, Bryan; Raymond, Carol A.

    2015-11-01

    The Dawn Framing Camera has revealed numerous domical to conical features on Ceres, which may have relevance to the presence and history of near-surface ice. These features fall into two broad classes, large domes 10s to >100 km in diameter exhibiting 1-5 km of positive relief, and small mounds <10 km in diameter exhibiting sub-kilometer relief. Here, we propose three hypotheses for the origin of the ~150 small mounds identified thus far, and discuss morphological observations that could support each hypothesis as higher resolution data becomes available.Hypothesis 1: Kilometer-scale mounds are produced by localized eruption of cryomagma or hydrothermal material. Observational tests: Kilometer and sub-kilometer scale albedo variations; sub-kilometer flow features on individual mounds; localized vents; conical or domical shape. Challenge: Features are smaller than convective plumes expected from thermal evolution modeling.Hypothesis 2: Kilometer-scale mounds are analogous to terrestrial and martian pingos, which grow by drawing liquid water through a silicate matrix as a freezing front propagates downward. Observational tests: Mounds occurring on smooth material that floods or embays large-scale features; little or no local albedo variation; no small flows associated with individual mounds; domical or ring-shape; concentric or radial fractures on dome, or central depression. Challenge: Small Cerean mounds observed thus far are an order of magnitude larger than terrestrial or martian pingos.Hypothesis 3: Kilometer-scale mounds are rootless cones analogous to features observed on the surface of volcanic flows in volatile-rich regions of Earth and Mars. Rootless cones are produced when layers of fluid material inundate a region; localized devolatilization of a layer mobilizes clasts to form cone-shaped deposits. Observational tests: Mounds on smooth material that floods or embays large-scale features; conical, not domical, profile; large central

  6. Wiggles and Wags: Dog 1--Fun Activities for You and Your Dog. 4-H Skills for Life Animal Series. National 4-H Curriculum. BU-08166

    ERIC Educational Resources Information Center

    National 4-H Council, 2005

    2005-01-01

    These guides are activity guides. Several fact-filled books about dogs are listed as resources on this guide. The activities are active, hands-on, and engaging and are guided by the 4-H motto: Learning by Doing. As youth explore a dog project topic of interest to them, they also practice essential life skills. Although a few dog project youth will…

  7. Science Targets in the Landing Ellipse and Lower Mound at the Gale Crater Field Site

    NASA Astrophysics Data System (ADS)

    Anderson, R. B.; Bell, J. F.

    2011-12-01

    The Mars Science Laboratory (MSL) rover Curiosity will land at the ~155 km diameter Gale Crater (4.6°S 137.2°E) in early August of 2012. The landing ellipse is centered in the northwestern floor of the crater on an alluvial fan composed of material from the crater rim. MSL will sample this material and test the hypothesis that the fan was deposited by flowing liquid water, and then drive south toward the base of the >5km tall central mound of layered rocks. Along this traverse, the smooth, low-thermal-inertia surface of the alluvial fan transitions to a fractured, layered, and spectrally neutral high thermal inertia unit. MSL will be able to assess the interpretation of this unit as cemented alluvial material and determine the cementing agent. Fresh craters in the high thermal inertia unit are important targets for MSL because their ejecta has had less exposure to the harsh radiation environment of the surface which can destroy biomarkers. Continuing south, MSL will descend across a short scarp where the units of the crater floor have eroded to expose the underlying basal unit of the mound. This erosion has formed ridged mesas interpreted to be lithified aeolian bedforms that are part of a widespread "mound-skirting" unit. MSL will test the hypothesis that this unit comprises debris shed from the mound during an early stage of erosion. The heavily fractured basal unit is partially obscured by relatively young mafic dunes, which will provide information about modern aeolian processes on Mars. After analyzing the basal unit and the dunes, MSL will begin climbing the layered rocks of the mound, beginning with a light-toned ridge which shows spectral evidence of hydrated sulfates. Beyond this ridge, the rover will encounter a phyllosilicate-bearing surface exposed in a trough paralleling the ridge. These lower mound layers are the primary targets of the MSL traverse. MSL will test the hypothesis that the lower mound sediments were deposited in a lacustrine setting

  8. Concentration of Actinides in Plant Mounds at Safety Test Nuclear Sites in Nevada

    SciTech Connect

    David S. Shafer; Jenna Gommes

    2008-09-15

    Plant mounds or blow-sand mounds are accumulations of soil particles and plant debris around large shrubs and are common features in deserts in the southwestern United States. Believed to be an important factor in their formation, the shrubs create surface roughness that causes wind-suspended particles to be deposited and resist further suspension. Shrub mounds occur in some plant communities on the Nevada Test Site, the Nevada Test and Training Range (NTTR), and Tonopah Test Range (TTR), including areas of surface soil contamination from past nuclear testing. In the 1970s as part of early studies to understand properties of actinides in the environment, the Nevada Applied Ecology Group (NAEG) examined the accumulation of isotopes of Pu, {sup 241}Am, and U in plant mounds at safety test sites. The NAEG studies found concentrations of these contaminants to be greater in shrub mounds than in the surrounding areas of desert pavement. For example, at Project 57 on the NTTR, it was estimated that 15 percent of the radionuclide inventory of the site was associated with shrub mounds, which accounted for 17 percent of the surface area of the site, a ratio of inventory to area of 0.85. At Clean Slate III at the TTR, 29 percent of the inventory was associated with approximately 32 percent of the site covered by shrub mounds, a ratio of 0.91. While the total inventory of radionuclides in intershrub areas was greater, the ratio of radionuclide inventory to area was 0.40 and 0.38, respectively, at the two sites. The comparison between the shrub mounds and adjacent desert pavement areas was made for only the top 5 cm since radionuclides at safety test sites are concentrated in the top 5 cm of intershrub areas. Not accounting for radionuclides associated with the shrub mounds would cause the inventory of contaminants and potential exposure to be underestimated. As part of its Environmental Restoration Soils Subproject, the U.S. Department of Energy (DOE), National Nuclear

  9. Carbonate mound reservoirs in the paradox formation: An outcrop analogue along the San Juan River, Southeastern Utah

    SciTech Connect

    Chidsey, T. C. Jr.; Morgan, C.D.; Eby, D.E.

    1996-06-01

    Carbonate mound reservoirs within the Pennsylvanian (Desmoinesian) Paradox Formation are major producers of oil and gas in the Paradox basin of Utah, Colorado, and Arizona. Outcrops of the Paradox Formation along the San Juan River of southeastern Utah provide small-scale analogues of reservoir heterogeneity, flow barriers and baffles, lithofacies, and geometry. These characteristics can be used in reservoir simulation models for secondary/tertiary recovery of oil from small fields in the basin. Exposures of the Paradox Formation Ismay zone in the Wild Horse Canyon area display lateral facies changes from phylloid algal mounds to off-mound detrital wedges or fans bounded at the top by a flooding surface. The phylloid mounds are composed of bafflestone, skeletal grainstone, packstone, and cementstone. Algal plates, brachiopods, bryozoans, and rugose corals are commonly found in the phylloid mounds. The mound wall is composed of rudstone, lumpstone, and cementstone. The detrital fan consists of transported algal material, grainstone, and mudstone with open-marine fossils. Within the mound complex is an inter-mound trough tentatively interpreted to be a tidal channel. The geometry and composition of the rocks in the trough significantly add to the overall heterogeneity of the mound. Reservoir models are being developed for possible water- and carbon-dioxide floods of small Paradox basin fields to determine the most effective secondary/tertiary recovery method. The models will include lithologic fabrics, flooding surfaces, and inter-mound troughs, based on the mound complex exposed at Wild Horse Canyon. This project may also provide reservoir information for simulation models in small Paleozoic carbonate mound fields in other basins worldwide.

  10. Synthesis and characterization of 4-aryl-4H-chromenes from H-cardanol.

    PubMed

    Rao, Hulluru Surya Prakash; Kamalraj, Mani

    2014-09-01

    We have synthesized and characterized a variety of fat-soluble, low-melting and medicinally useful 4-aryl-4H-chromenes from H-cardanol (side-chain perhydrogenated cardanol, 3-pentadecylphenol), a renewable and low-cost product from locally grown cashew nut trees (Anacardium occidentale L.). We incorporated H-cardanol into the aromatic rings of either 4H-chromene or phenol, or both. Substitution of C4SMe in N-methyl-4-(methylthio)-3-nitro-4H-chromene-2-amines with H-cardanol was regio-specific at the C6 position. PMID:25918806

  11. Using Multiple Youth Programming Delivery Modes to Drive the Development of Social Capital in 4-H Participants

    ERIC Educational Resources Information Center

    Kinsey, Sharon

    2013-01-01

    This article focuses on how 4-H youth participants are building social capital, or connections among individuals and community members, through their 4-H experiences. These experiences can be seen through the lens of such 4-H delivery modes as the traditional 4-H club, after-school programs, and school enrichment programs. In addition, other…

  12. HiRISE Observations of Martian Mid-Latitude Fractured Mounds

    NASA Astrophysics Data System (ADS)

    Dundas, C. M.; Mellon, M. T.; McEwen, A. S.; Lefort, A.; Keszthelyi, L. P.; Thomas, N.; HiRISE Team

    2007-12-01

    The High Resolution Imaging Science Experiment (HiRISE) camera has now returned thousands of images of the Martian surface with pixel scale as small as 26 cm/pixel. These have revealed fractured mounds up to several hundred meters in diameter, bearing some morphological resemblance to terrestrial pingos (ice-cored hills formed by freezing groundwater). Pingos on Mars would be valuable indicators of ground ice and have been suggested at a number of sites, but in several cases reexamination has supported different origins. Some differences do exist between the fractured mounds and terrestrial pingos. In several instances, the mounds have roughly trapezoidal topographic profiles with flat, fractured summits. Other morphologies are also seen; we report on the range of morphologies observed so far by HiRISE and similarities and differences with pingos on Earth. The fractured mounds observed to date generally appear in the mid-latitudes, at a range of longitudes. Mars Orbiter Camera (MOC) images of flat-topped mounds in Utopia Planitia (including some previously proposed pingos) show a similar latitudinal dependence, generally occurring between 35-45° N. This supports a ground- ice related origin, particularly since the latitude range is close to the peak-abundance latitude of some other features likely related to water or ice, such as gullies. It is still uncertain whether the formation mechanism of the fractured mounds is the same as terrestrial pingos in detail. We discuss the distribution, properties and settings of fractured mounds observed planet-wide by HiRISE.

  13. Permanent groundwater storage in basaltic dyke fractures and termite mound viability

    NASA Astrophysics Data System (ADS)

    Mège, Daniel; Rango, Tewodros

    2010-04-01

    Many basaltic dykes of the Ethiopian flood basalt province are observed in the northwestern Ethiopian lowlands. In this area, the termites preferentially build their epigeous mounds on the top of dolerite dykes. The relationship between termite mounds and dykes is investigated from the analysis of their distribution along one of these dykes, of thickness 2-5 m, that we could follow over 2000 m. Termite mounds are periodically spaced (mean distance 63 m, R2 = 0.995), and located exclusively where the topographic relief of the dyke is not more than 2 m above the surrounding area. From these observations and from the geological context, a hydrological circuit model is proposed in which (1) dykes are preferential conduits for groundwater drainage during the rainy season due to pervasive jointing, (2) during the dry season, the portion of the dyke forming a local topographic relief area dries up more quickly than the surroundings, the elevation difference between the dyke summit and the surroundings being a factor restricting termite mound development. For dyke topographic relief >2 m, drying is an obstacle for maintaining the appropriate humidity for the termite colony life. Periodic termite mound spacing is unlikely to be related to dyke or other geological properties. It is more likely related to termite population behaviour, perhaps to clay shortage, which restricts termite population growth by limiting the quantity of building material available for mound extension, and triggers exploration for a new colonization site that will be located along the dyke at a distance from the former colony that may be controlled by the extent of the zone covered by its trail pheromones. This work brings out the importance of dykes in channelling and storing groundwater in semiarid regions, and shows that dykes can store groundwater permanently in such settings even though the dry season is half the year long. It contributes also to shedding light on water supply conditions

  14. Microbial Biodiversity in the Subsurface of Carbonate Mounds from the Gulf of Cadiz off Morocco

    NASA Astrophysics Data System (ADS)

    Templer, S. P.; Stadnitskaia, A.; de Haas, H.; Bernasconi, S.; Vasconcelos, C.; McKenzie, J. A.

    2008-12-01

    The study area, El Arraiche mud volcano field, is situated 35 km offshore the north-western Moroccan margin, on top of the accretionary wedge of the Gulf of Cadiz. An exploratory cruise of R/V Belgica in 2002 off Larache (Morocco) has led to the discovery of small mounds topping ridges and structural heights, respectively on Pen Duick Escarpment, Renard Ridge, Vernadsky Ridge and Al Idrisi Ridge. These mounds are found amidst 9 giant mud volcanoes and occur in a setting where focused fluid seepage is observed. Subsequent cruises have confirmed the colonization by dominantly lifeless cold-water corals and have unveiled extensive fields of seep-related carbonates in off-reef regions. We present the microbial biodiversity of the subsurface of two different carbonate mounds (alpha- and beta-mound) flanked by a giant double- peaked mud volcano in the Pen Duick Mound Province in a water depths of 500-600 m. Most of the sediment comprises pelagic calcite (coccoliths), detrital quartz and authigenic dolomite, often observed encasing coccoliths. Stable carbon isotope values of the bulk carbonate range from -7 to -15 permil indicating the involvement of microbes in the production of bicarbonate ions. Pore water analysis evidences a sharp sulphate-methane-transition (SMT) zone at 3.5 m below the mound top, whereas the depth of no sulfate is much deeper in the surrounding sediments. The horizon characterized by a strong corrosion of the coral fragments is just lying above and at the front of the recent location of the zone of anaerobic methane oxidation (AOM). In order to define the primary microbial community involved in carbonate precipitation, we did direct culturing, DNA isolation and PCR analysis of functional genes, including archaeal and bacterial 16S rRNA gene analysis. In combination with a DGGE approach, we developed a microbial biodiversity profile along the two carbonate mounds.

  15. Lithofacies distribution and reservoir heterogeneity within Pennsylvanian phylloid algal mounds, western Orogrande basin, New Mexico

    SciTech Connect

    Giles, K.A.; Soreghan, G.S.

    1996-12-31

    Pennsylvanian strata within the San Andres Mountains (western Orogrande basin) contain very well-developed phylloid algal bioherms, but these bioherms remain understudied owing to their location within the bounds of the U.S. Army White Sands Missile Range. The exposed Upper Pennsylvanian section within Hembrillo Canyon affords a three-dimensional view of mound structure, and thus an excellent opportunity for characterizing lithofacies distribution and reservoir heterogeneity that may prove useful for exploration/exploitation efforts in analogous petroliferous systems. The mounds are developed within a mixed carbonate-clastic shallow marine section punctuated by shoaling-upward cycles. Each mound site consists of a slack of individual biohermal growth events characterized by a subtidal wackestone initiation phase, core boundstone phase, and peritidal to subaerially exposed packstone/grainstone terminal phase. Individual biohermal growth events range up to 30 m in thickness; vertical stacking of these bioherms has produced aggregate mounds reaching up to 100 m in stratigraphic thickness and 300 m in diameter. Individual blohermal thicknesses decrease abruptly and markedly away from mound sites, and calcareous mudstones dominate in intermound regions. The controlling influences of paleogeography and glacioeustasy, respectively, produced the pronounced lateral and vertical heterogeneity characterizing these and analogous phylloid algal mound systems. Reservoirs within these systems are highly compartmentalized: wackestone initiation phases and peritidal to subaerial termination phases that envelope core facies may serve as porosity and permeability barriers that effectively partition the reservoir. Recognition of the scale, character, and probable controls on these lateral and vertical changes is important for effective exploration and exploitation in phylloid algal mound systems.

  16. Gopher mounds decrease nutrient cycling rates and increase adjacent vegetation in volcanic primary succession.

    PubMed

    Yurkewycz, Raymond P; Bishop, John G; Crisafulli, Charles M; Harrison, John A; Gill, Richard A

    2014-12-01

    Fossorial mammals may affect nutrient dynamics and vegetation in recently initiated primary successional ecosystems differently than in more developed systems because of strong C and N limitation to primary productivity and microbial communities. We investigated northern pocket gopher (Thomomys talpoides) effects on soil nutrient dynamics, soil physical properties, and plant communities on surfaces created by Mount St. Helens' 1980 eruption. For comparison to later successional systems, we summarized published studies on gopher effects on soil C and N and plant communities. In 2010, 18 years after gopher colonization, we found that gophers were active in ~2.5% of the study area and formed ~328 mounds ha(-1). Mounds exhibited decreased species density compared to undisturbed areas, while plant abundance on mound margins increased 77%. Plant burial increased total soil carbon (TC) by 13% and nitrogen (TN) by 11%, compared to undisturbed soils. Mound crusts decreased water infiltration, likely explaining the lack of detectable increases in rates of NO3-N, NH4-N or PO4-P leaching out of the rooting zone or in CO2 flux rates. We concluded that plant burial and reduced infiltration on gopher mounds may accelerate soil carbon accumulation, facilitate vegetation development at mound edges through resource concentration and competitive release, and increase small-scale heterogeneity of soils and communities across substantial sections of the primary successional landscape. Our review indicated that increases in TC, TN and plant density at mound margins contrasted with later successional systems, likely due to differences in physical effects and microbial resources between primary successional and older systems.

  17. Lithofacies distribution and reservoir heterogeneity within Pennsylvanian phylloid algal mounds, western Orogrande basin, New Mexico

    SciTech Connect

    Giles, K.A. ); Soreghan, G.S. )

    1996-01-01

    Pennsylvanian strata within the San Andres Mountains (western Orogrande basin) contain very well-developed phylloid algal bioherms, but these bioherms remain understudied owing to their location within the bounds of the U.S. Army White Sands Missile Range. The exposed Upper Pennsylvanian section within Hembrillo Canyon affords a three-dimensional view of mound structure, and thus an excellent opportunity for characterizing lithofacies distribution and reservoir heterogeneity that may prove useful for exploration/exploitation efforts in analogous petroliferous systems. The mounds are developed within a mixed carbonate-clastic shallow marine section punctuated by shoaling-upward cycles. Each mound site consists of a slack of individual biohermal growth events characterized by a subtidal wackestone initiation phase, core boundstone phase, and peritidal to subaerially exposed packstone/grainstone terminal phase. Individual biohermal growth events range up to 30 m in thickness; vertical stacking of these bioherms has produced aggregate mounds reaching up to 100 m in stratigraphic thickness and 300 m in diameter. Individual blohermal thicknesses decrease abruptly and markedly away from mound sites, and calcareous mudstones dominate in intermound regions. The controlling influences of paleogeography and glacioeustasy, respectively, produced the pronounced lateral and vertical heterogeneity characterizing these and analogous phylloid algal mound systems. Reservoirs within these systems are highly compartmentalized: wackestone initiation phases and peritidal to subaerial termination phases that envelope core facies may serve as porosity and permeability barriers that effectively partition the reservoir. Recognition of the scale, character, and probable controls on these lateral and vertical changes is important for effective exploration and exploitation in phylloid algal mound systems.

  18. Office of Inspector General report on audit of shutdown and transition of the Mound Plant

    SciTech Connect

    1997-06-24

    With the end of the Cold War, the Department of Energy (Department) has greatly reduced the production of nuclear weapons and redirected the capabilities and focus of the weapons complex. As part of this redirection, the Mound Plant was transferred from a Defense Program site to an Environmental Management site with emphasis on accelerated cleanup and transition of facilities and personal property to the local community. This audit was initiated to determine if the shutdown and transition of the Mound Plant was progressing effectively and efficiently. The Department prepared a Nonnuclear Consolidation Plan (NCP) designed to reduce its costs of operation by closing and consolidating facilities. In contrast to the goal of the NCP, the Department plans to keep a portion of the Mound Plant open solely to perform work for other Federal agencies. Specifically, the Department has decided to continue assembling and testing isotopic heat sources and radioisotope thermoelectric generators (HS/RTG) at the Mound Plant despite the transfer or planned transfer of all other production operations.The Office of Nuclear Energy, Science and Technology decided to continue its HS/RTG operations at the Mound Plant without adequately considering the overall economic goals of the Department. As a result, the Department may not achieve the savings envisioned by the NCP. Also, the Department may incur between $4 million and $8.5 million more than necessary each year to continue its HS/RTG operations at the Mound Plant. Additionally, if the HS/RTG operations stay at the Mound Plant, the Department will spend more than $3 million to consolidate these operations into one location.

  19. A photographic and acoustic transect across two deep-water seafloor mounds, Mississippi Canyon, northern Gulf of Mexico

    USGS Publications Warehouse

    Hart, P.E.; Hutchinson, D.R.; Gardner, J.; Carney, R.S.; Fornari, D.

    2008-01-01

    In the northern Gulf of Mexico, a series of seafloor mounds lie along the floor of the Mississippi Canyon in Atwater Valley lease blocks 13 and 14. The mounds, one of which was drilled by the Chevron Joint Industry Project on Methane Hydrates in 2005, are interpreted to be vent-related features that may contain significant accumulations of gas hydrate adjacent to gas and fluid migration pathways. The mounds are located ???150 km south of Louisiana at ???1300 m water depth. New side-scan sonar data, multibeam bathymetry, and near-bottom photography along a 4 km northwest-southeast transect crossing two of the mounds (labeled D and F) reveal the mounds' detailed morphology and surficial characteristics. Mound D, ???250 m in diameter and 7-10 m in height, has exposures of authigenic carbonates and appears to result from a seafloor vent of slow-to-moderate flux. Mound F, which is ???400 m in diameter and 10-15 m high, is covered on its southwest flank by extruded mud flows, a characteristic associated with moderate-to-rapid flux. Chemosynthetic communities visible on the bottom photographs are restricted to bacterial mats on both mounds and mussels at Mound D. No indications of surficial gas hydrates are evident on the bottom photographs.

  20. Hydrophobins Sc3 and Sc4 gene expression in mounds, fruiting bodies and vegetative hyphae of Schizophyllum commune.

    PubMed

    Banerjee, Goutami; Robertson, Deborah L; Leonard, Thomas J

    2008-03-01

    An abnormal growth form called mound has been hypothesized to be a neoplasm in the filamentous fungus Schizophyllum commune. An alternative hypothesis is that mounds represent some unusual developmental form in the fruiting body morphogenetic pathway. Hydrophobin proteins have been found in fruiting bodies where they line the surface of gas exchange pores and function to keep the pores hydrophobic. To further determine possible relationships between mounds and fruiting bodies, mound tissue was examined for gas exchange pores and the presence of hydrophobins. Cryoscanning electron microscopic images revealed the presence of channels in mound tissue and presumptive hydrophobin rodlets similar to the air channels in fruiting bodies. Hydrophobin gene expression was also measured in mound tissue using quantitative real-time PCR and showed both monokaryotic and dikaryotic mound tissue exhibited high expression of the dikaryotic specific Sc4 hydrophobin gene. In contrast, Sc4 hydrophobin expression was barely detectable in monokaryotic fruiting bodies. The expression of Sc4 hydrophobin genes in mounds suggests mound development uses this aspect of the dikaryotic fruiting developmental pathway.

  1. Comparison of two carbonate mound sequences in the Lower Ordovician El Paso Formation, west Texas and southern New Mexico

    SciTech Connect

    Clemons, R.E.

    1985-01-01

    The El Paso Formations consists of four members, in ascending order: Hitt Canyon, Jose McKelligon and Padre. Mounds in the McKelligon Member exposed in the southern Franklin Mountains were described by Toomey (1970). Most of these mounds are small but one large one is 5.8 m thick and about 13.7 m long in outcrop. The mound rock is chiefly bioclastic wackestone with minor packstone and boundstone. The varied fauna contains echinoderms, sponges and spicules, gastropods, trilobites, digitate algae, Nuia, Girvanella, Pulchrilamina, Calathium, and minor brachiopods and cephalopods. Intraclastic, bioclastic grainstone fills channels cut in the mounds. Similar, but smaller and less spectacular mounds occur in the McKelligon Member in the Florida, Big Hatchet, and Caballo Mountains, Lone Mountain, Cooke's Range, and elsewhere in southwestern New Mexico. A second type of mound is common in the upper part of the Hitt Canyon Member in the Cooke's Range, Red Hills, Caballo and Big Hatchet Mountains. These mounds also are typically small but one in the Red Hills is 13.7 m thick and about 30 m long in outcrop. The mound complex is about 75-80% SH-C and LLH-C stromatolite boundstone and bioclastic wackestone. The remaining 20-25% is bioclastic packstone and grainstone between the SH-C stromatolites and filling channels cut in the mound complex. The limited fauna contains small fragments of echinoderms, gastropods, trilobites, spicules, and Nuia.

  2. Reaching Migrant Farmworker Youth through 4-H Career and Workforce Programs.

    ERIC Educational Resources Information Center

    Wille, Celina G.

    1999-01-01

    Migrant-farm-worker youth learned about employment and educational opportunities in agriculture through a 4-H-sponsored conference. The conference was developed by a partnership of university extension, community organizations, schools, and private industry. (SK)

  3. Ferromagnetism in proton irradiated 4H-SiC single crystal

    SciTech Connect

    Zhou, Ren-Wei; Wang, Hua-Jie; Chen, Wei-Bin; Li, Fei; Liu, Xue-Chao Zhuo, Shi-Yi; Shi, Er-Wei

    2015-04-15

    Room-temperature ferromagnetism is observed in proton irradiated 4H-SiC single crystal. An initial increase in proton dose leads to pronounced ferromagnetism, accompanying with obvious increase in vacancy concentration. Further increase in irradiation dose lowers the saturation magnetization with the decrease in total vacancy defects due to the defects recombination. It is found that divacancies are the mainly defects in proton irradiated 4H-SiC and responsible for the observed ferromagnetism.

  4. Phosphorus doping of 4H SiC by liquid immersion excimer laser irradiation

    SciTech Connect

    Ikeda, Akihiro; Nishi, Koji; Ikenoue, Hiroshi; Asano, Tanemasa

    2013-02-04

    Phosphorus doping of 4H SiC is performed by KrF excimer laser irradiation of 4H SiC immersed in phosphoric acid. Phosphorus is incorporated to a depth of a few tens of nanometers at a concentration of over 10{sup 20}/cm{sup 3} without generating significant crystal defects. Formation of a pn junction diode with an ideality factor of 1.06 is demonstrated.

  5. Seepage carbonate mounds in Cenozoic sedimentary sequences from the Las Minas Basin, SE Spain

    NASA Astrophysics Data System (ADS)

    Pozo, M.; Calvo, J. P.; Scopelliti, G.; González-Acebrón, L.

    2016-04-01

    A number of carbonate mounds composed of indurate, strongly folded and/or brecciated calcite and dolomite beds occur interstratified in Cenozoic sedimentary sequences from the Las Minas Basin. Part of the fabric of the rock forming the carbonate mounds is composed of laminated to banded dolostone similar to the host rock but showing contrasted lithification. Moreover, the carbonate deposits of the mounds display aggrading neomorphism of dolomite, partial replacement of dolomite by calcite, calcite cementation, and extensive silicification, locally resulting in box-work fabric. Eight main lithofacies were distinguished in the carbonate mound deposits. In some lithofacies, chert is present as both microcrystalline to fibro-radial quartz and opal, the latter occurring mainly as cement whereas the former replace the carbonate and infill voids. Yet one of the carbonate mounds shows distinctive petrography and geochemical features thus suggesting a distinctive growth pattern. The carbon isotope compositions of calcite from the mound samples range from - 11.56 to - 5.15 δ‰ whilst dolomite is depleted in 13C, with values of - 12.38 to 3.02 δ‰. Oxygen isotopic compositions vary from - 9.42 to - 4.64 δ‰ for calcite and between - 6.68 and 8.19 δ‰ for dolomite. Carbonate in the mounds shows significant enrichment in Co, Cr, Ni and Pb content, especially in the strongly deformed (F-2-2 lithofacies) and brecciated carbonate (F-4). The carbonate deposits show depletion in REE and Y in contrast to that determined in lutite. The formation of the carbonate mounds was related to local artesian seepage thermal water flows of moderate to relative high temperatures. Pressure differences between the low permeability host rock and the circulating fluids accounted for dilational fracturing and brecciation of the host sediment packages, which combined with precipitation of new carbonate and silica mineral phases. Locally, some carbonate mounds developed where groundwater

  6. Fabrication of High-Q Nanobeam Photonic Crystals in Epitaxially Grown 4H-SiC.

    PubMed

    Bracher, David O; Hu, Evelyn L

    2015-09-01

    Silicon carbide (SiC) is an intriguing material due to the presence of spin-active point defects in several polytypes, including 4H-SiC. For many quantum information and sensing applications involving such point defects, it is important to couple their emission to high quality optical cavities. Here we present the fabrication of 1D nanobeam photonic crystal cavities (PCC) in 4H-SiC using a dopant-selective etch to undercut a homoepitaxially grown epilayer of p-type 4H-SiC. These are the first PCCs demonstrated in 4H-SiC and show high quality factors (Q) of up to ∼7000 as well as low modal volumes of <0.5 (λ/n)(3). We take advantage of the high device yield of this fabrication method to characterize hundreds of devices and determine which PCC geometries are optimal. Additionally, we demonstrate two methods to tune the resonant wavelengths of the PCCs over 5 nm without significant degradation of the Q. Lastly, we characterize nanobeam PCCs coupled to luminescence from silicon vacancy point defects (V1, V2) in 4H-SiC. The fundamental modes of two such PCCs are tuned into spectral overlap with the zero phonon line (ZPL) of the V2 center, resulting in an intensity increase of up to 3-fold. These results are important steps on the path to developing 4H-SiC as a platform for quantum information and sensing.

  7. The crystal structure of "green" Cs 2[VOF 4(H 2O)] and its relationship to "blue" Cs 2[VOF 4(H 2O)

    NASA Astrophysics Data System (ADS)

    Mattes, Rainer; Foerster, Harry

    1982-11-01

    Crystals of a second, "green" modification of Cs 2[VOF 4(H 2O)] were obtained from aqueous solution. Their crystal structure was studied on the basis of three-dimensional X-ray data. The structure is orthorhombic, a = 8.231(3), b = 10.323(3), c = 8.497(3) Å, V = 722.0Å 3, Z = 4, space group Ccmm. The final R and RW were 0.035 and 0.048, respectively, for 421 independent reflections. As the already known "blue" modification, the present structure contains isolated, highly deformed octahedral [VOF 4(H 2O)] 2- ions with the oxygen atoms in trans positions. The cesium sublattice and the orientation of the anions to each other are completely different in both modifications. uv/VIS reflection, and ir and Raman spectra of both modifications are discussed.

  8. The character, origin and palaeoenvironmental significance of the Wonderkrater spring mound, South Africa

    NASA Astrophysics Data System (ADS)

    McCarthy, T. S.; Ellery, W. N.; Backwell, L.; Marren, P.; Klerk, B. de; Tooth, S.; Brandt, D.; Woodborne, S.

    2010-08-01

    Wonderkrater is a spring mound consisting entirely of peat in excess of 8 m thick. It has yielded a pollen record extending back over 35,000 years, which has provided one of the very few proxy climatic records for the interior of southern Africa in the Late Pleistocene and Holocene. The current investigation of the morphology and sedimentology of the site has revealed that the peat mound formed due to artesian conditions at the spring, but that accumulation of the thick peat succession was made possible because of clastic sedimentation on the surrounding piedmont which in turn was brought about by aggradation on the adjacent Nyl River floodplain. The peat mound has remained elevated relative to the surrounding piedmont for most of the 35,000 year period. Aggradation of the mound was slower during the Late Pleistocene than the Holocene (0.06-0.1 m/1000 year and 0.2-0.38 m/1000 year, respectively). Controlled archaeological excavations yielded a diverse late Pleistocene fauna preserved in peat and sand in the mound. A 1 m thick, coarse sand horizon at the base of the peat deposit contained a rich Middle Stone Age (>30 k year) lithic assemblage. The MSA sand layer likely represents an arid phase, suggesting the site's antiquity as a place of refuge for Quaternary animals and the people that hunted them.

  9. Soil respiration in pits and mounds following an experimental forest blowdown

    SciTech Connect

    Millikin, C.S.; Bowden, R.D.

    1996-11-01

    Extensive uprooting of trees by windthrow can create areas of severe soil disturbance in temperate forests. Specifically, uprooted trees leave shaded pits and mounds of exposed roots and mineral soil. To assess the contribution of pit and mound microenvironments to overall soil respiration in an experimental hurricane blowdown at the Harvard Forest Long-Term Ecological Research site (MA), summer CO{sub 2} effluxes were measured on pit, mound, and undisturbed microsites. Mean CO{sub 2} effluxes were 45.4, 80.1, and 99.0 mgC m{sup -2} h{sup -1} for pit, mound, and control microsites, respectively. Although soil respiration is lower in areas of disturbed soil than in undisturbed areas, the total efflux contribution (5.3%) form pits and mounds to the overall flux rate at the site was small. The area-weighted soil respiration estimate is 3.1% lower than the estimate obtained using flux measurements from control locations alone. Measurements taken from undisturbed plots represent a small but systematic overestimate of soil respiration across the site. 25 refs., 1 fig.

  10. [Spatial correlation of active mounds locative distribution of Solenopsis invicta Buren polygyne populations].

    PubMed

    Lu, Yong-yue; Li, Ning-dong; Liang, Guang-wen; Zeng, Ling

    2007-01-01

    By using geostatistic method, this paper studied the spatial distribution patterns of the active mounds of Solenopsis invicta Buren polygyne populations in Wuchuan and Shenzhen, and built up the spherical models of the interval distances and semivariances of the mounds. The semivariograms were described at the two directions of east-west and south-north, which were obviously positively correlated to the interval distances, revealing that the active mounds in locative area were space-dependent. The ranges of the 5 spherical models constructed for 5 sampling plots in Wuchuan were 9.1 m, 7.6 m, 23.5 m, 7.5 m and 14.5 m, respectively, with an average of 12.4 m. The mounds of any two plots in this range were significantly correlated. There was a randomicity in the spatial distribution of active mounds, and the randomicity index (Nugget/Sill) was 0.7034, 0.9247, 0.4398, 1.1196 and 0.4624, respectively. In Shenzhen, the relationships between the interval distances and semivariances were described by 7 spherical models, and the ranges were 14.5 m, 11.2 m, 10.8 m, 17.6 m, 11.3 m, 9.9 m and 12.8 m, respectively, with an average of 12.6 m.

  11. Behavior of subaqueous sediment mounds: Effect on dredged material disposal site capacity

    SciTech Connect

    Poindexter, M.E.

    1988-01-01

    Dredging of contaminated sediments and subsequent disposal at legally designated disposal sites is an internationally accepted disposal alternative when adherence to strict disposal practices is maintained. As more highly contaminated sediments in the heavily industrialized harbors of the world must be dredged to maintain navigation and economic viability, use of subaqueous dredged material disposal sites is expected to increase. Use of these subaqueous sites has necessitated development of procedures to analyze disposal site capacity based upon physical, chemical, and biological considerations. A methodology of analysis was developed in this study to investigate the behavior of the crated subaqueous sediment mounds. Emphasis was placed upon the geotechnical engineering aspects of mound behavior although the methodology also includes chemical and biological aspects. This methodology was applied to four field sites at which dredged material mounds have been created. The procedure successfully predicted the geotechnical engineering behavior of the constructed dredged material mounds. This methodology of analysis provides a useful tool for evaluation of subaqueous disposal sites and the dredged materials mounds created within these sites.

  12. The malar septum: the anatomic basis of malar mounds and malar edema.

    PubMed

    Pessa, J E; Garza, J R

    1997-01-01

    The anatomy of malar mounds and malar edema is evaluated in a series of 18 fresh cadaver dissections. Dye injection, histologic evaluation, and gross anatomic dissection are used to identify a previously unrecognized fascial structure of the lower eyelid and cheek. The malar septum originates from orbital rim periosteum superiorly and inserts into cheek skin 2.5 to 3 cm inferior to the lateral canthus. This fascial structure acts as a relatively impermeable barrier that allows tissue edema and hemoglobin pigment to accumulate above its cutaneous insertion. The malar septum, which acts as both a functional and a structural barrier, defines the lower boundary of several clinical entities: malar mounds, malar edema, malar festoons, and periorbital ecchymosis. The permeability characteristics of the malar septum suggest that, at least in some persons, malar mounds may be accentuated by chronic lower eyelid edema, and these characteristics may imply a time course in the progressive development from malar edema to malar mounds and, ultimately, to malar festoons. The anatomy of the malar septum is clinically relevant because it defines the four anatomic compartments of the malar mound that should be considered during surgery: the superior compartment of suborbicularis oculi fat, orbicularis oculi muscle, and superficial cheek fat and cheek skin superior to the cutaneous insertion of the malar septum.

  13. Environmental assessment and planning at Mound - environmental monitoring capabilities and personnel profiles

    SciTech Connect

    1996-07-01

    Through its long experience with radioactive materials, Mound has developed a comprehensive, routine, offsite, environmental surveillance program to safeguard its employees, the physical plant, and the integrity of the surrounding environment from any potential adverse effects of its widely diverse operations. Effluent samples are analyzed for radiological and non-radiological parameters. The environment surrounding Mound Facility is continuously monitored - air, water, foodstuffs, vegetation, soil, and silt samples are analyzed to ensure that radioisotopic concentrations and other possible pollutants are well within the stringent standards adopted by the Department of Energy, the Environmental Protection Agencies (both federal and state), and various regional and local agencies. Moreover, this environmental surveillance program has been designed to ensure that the facility is designed, constructed, managed, operated, and maintained in a manner that continues to meet all federal, state, and local standards for environmental protection. Work in environmental science has been broadened to assess environmental factors associated with various aspects of the National Energy Plan. Both the management and staff at Mound have undertaken a firm commitment to make Mound`s environmental monitoring capabilities available to agencies that have the responsibility for the resolution of important environmental issues.

  14. Conversion of the Bryan Mound geological site characterization reports to a three-dimensional model.

    SciTech Connect

    Stein, Joshua S.; Rautman, Christopher Arthur

    2005-04-01

    The Bryan Mound salt dome, located near Freeport, Texas, is home to one of four underground crude oil-storage facilities managed by the U. S. Department of Energy Strategic Petroleum Reserve (SPR) Program. Sandia National Laboratories, as the geotechnical advisor to the SPR, conducts site-characterization investigations and other longer-term geotechnical and engineering studies in support of the program. This report describes the conversion of two-dimensional geologic interpretations of the Bryan Mound site into three-dimensional geologic models. The new models include the geometry of the salt dome, the surrounding sedimentary units, mapped faults, and the 20 oil-storage caverns at the site. This work provides an internally consistent geologic model of the Bryan Mound site that can be used in support of future work.

  15. The induction of atherosclerotic plaque-like mounds in cultures of aortic smooth muscle cells.

    PubMed

    May, J F; Paule, W J; Rounds, D E; Blankenhorn, D H; Zemplenyi, T

    1975-07-18

    Smooth muscle cells harvested from the tunica media of piglet aortae were maintained in continous culture for 10 months. When grown in the presence of 95% air and 5% CO2 they maintained a mature morphology as evaluated ultrastructurally. As these populations became confluent, the cells became oriented parallel to each other. When grown in the presence of 4% O2, 91% N2, and 5% CO2, this polarized pattern was disrupted. Focal areas of lipid accumulation were observed, succeeded by mound formation at these sites. The mound stained positive with PAS, aldehyde fuchsin, and oil red O. They were surrounded by 2-4 layers of intact cells. The centers of the mound were composed of extracellular material and cell debris.

  16. Distribution and physical traits of red wood ant mounds in a managed Rhodope mountains forest.

    PubMed

    Tsikas, Angelos; Karanikola, Paraskevi; Papageorgiou, Aristotelis C

    2016-07-01

    Red wood ants (RWA) are of great ecological importance for the forest ecosystem. Forestry practices, like clear-cutting, and trampling load, due to tourism, logging, and grazing stock, can greatly affect their colonies, disturbing their microhabitat. RWA in Greek forests have not been investigated so far. We herein report on the distribution and morphological traits of Formica lugubris mounds studied in Elatia forest (Rhodope mountains, Northern Greece), an all-aged managed mixed forest where selective logging practices are performed. Nearby vegetation, slope, canopy cover, shrub density, and distance from the nearest neighboring trees were also recorded. Mound density was shown to be much higher in this Greek forest compared to RWA mounds in other European-managed forests. Furthermore, we recorded a continuous nest establishment, despite forest management disturbances and trampling load. Our study suggests that single-tree selective forestry practices are essential for creating ideal microhabitats for the RWA and, therefore, for maintaining RWA populations.

  17. Distribution and physical traits of red wood ant mounds in a managed Rhodope mountains forest.

    PubMed

    Tsikas, Angelos; Karanikola, Paraskevi; Papageorgiou, Aristotelis C

    2016-07-01

    Red wood ants (RWA) are of great ecological importance for the forest ecosystem. Forestry practices, like clear-cutting, and trampling load, due to tourism, logging, and grazing stock, can greatly affect their colonies, disturbing their microhabitat. RWA in Greek forests have not been investigated so far. We herein report on the distribution and morphological traits of Formica lugubris mounds studied in Elatia forest (Rhodope mountains, Northern Greece), an all-aged managed mixed forest where selective logging practices are performed. Nearby vegetation, slope, canopy cover, shrub density, and distance from the nearest neighboring trees were also recorded. Mound density was shown to be much higher in this Greek forest compared to RWA mounds in other European-managed forests. Furthermore, we recorded a continuous nest establishment, despite forest management disturbances and trampling load. Our study suggests that single-tree selective forestry practices are essential for creating ideal microhabitats for the RWA and, therefore, for maintaining RWA populations. PMID:27345521

  18. Analysis of cavern stability at the Bryan Mound SPR site.

    SciTech Connect

    Ehgartner, Brian L.; Sobolik, Steven Ronald

    2009-04-01

    This report presents computational analyses that simulate the structural response of caverns at the Strategic Petroleum Reserve Bryan Mound site. The cavern field comprises 20 caverns. Five caverns (1, 2, 4, and 5; 3 was later plugged and abandoned) were acquired from industry and have unusual shapes and a history dating back to 1946. The other 16 caverns (101-116) were leached according to SPR standards in the mid-1980s and have tall cylindrical shapes. The history of the caverns and their shapes are simulated in a 3-D geomechanics model of the site that predicts deformations, strains, and stresses. Future leaching scenarios due to oil drawdowns using fresh water are also simulated by increasing the volume of the caverns. Cavern pressures are varied in the model to capture operational practices in the field. The results of the finite element model are interpreted to provide information on the current and future status of subsidence, well integrity, and cavern stability. The most significant result in this report is relevant to caverns 1, 2, and 5. The caverns have non-cylindrical shapes and have potential regions where the surrounding salt may be damaged during workover procedures. During a workover the normal cavern operating pressure is lowered to service a well. At this point the wellhead pressures are atmospheric. When the workover is complete, the cavern is repressurized. The resulting elastic stresses are sufficient to cause tension and large deviatoric stresses at several locations. With time, these stresses relax to a compressive state due to salt creep. However, the potential for salt damage and fracturing exists. The analyses predict tensile stresses at locations with sharp-edges in the wall geometry, or in the case of cavern 5, in the neck region between the upper and lower lobes of the cavern. The effects do not appear to be large-scale, however, so the only major impact is the potential for stress-induced salt falls in cavern 5, potentially leading to

  19. Antarctic Mirabilite Mounds as Mars Analogs: The Lewis Cliffs Ice Tongue Revisited

    NASA Technical Reports Server (NTRS)

    Socki, Richard A.; Sun, Tao; Niles, Paul B.; Harvey, Ralph P.; Bish, David L.; Tonui, Eric

    2012-01-01

    It has been proposed, based on geomorphic and geochemical arguments, that subsurface water has played an important role in the history of water on the planet Mars [1]. Subsurface water, if present, could provide a protected and long lived environment for potential life. Discovery of gullies [2] and recurring slopes [3] on Mars suggest the potential for subsurface liquid water or brines. Recent attention has also focused on small (< approx. 1km dia.) mound-like geomorphic features discovered within the mid to high latitudes on the surface of Mars which may be caused by eruptions of subsurface fluids [4, 5]. We have identified massive but highly localized Na-sulfate deposits (mirabilite mounds, Na2SO4 .10H2O) that may be derived from subsurface fluids and may provide insight into the processes associated with subsurface fluids on Mars. The mounds are found on the end moraine of the Lewis Cliffs Ice Tongue (LCIT) [6] in the Transantarctic Mountains, Antarctica, and are potential terrestrial analogs for mounds observed on the martian surface. The following characteristics distinguish LCIT evaporite mounds from other evaporite mounds found in Antarctic coastal environments and/or the McMurdo Dry Valleys: (1) much greater distance from the open ocean (approx.500 km); (2) higher elevation (approx.2200 meters); and (3) colder average annual temperature (average annual temperature = -30 C for LCIT [7] vs. 20 C at sea level in the McMurdo region [8]. Furthermore, the recent detection of subsurface water ice (inferred as debris-covered glacial ice) by the Mars Reconnaissance Orbiter [9] supports the use of an Antarctic glacial environment, particularly with respect to the mirabilite deposits described in this work, as an ideal terrestrial analog for understanding the geochemistry associated with near-surface martian processes. S and O isotopic compositions.

  20. Can mima-like mounds be Vertisol relics (Far North Region of Cameroon, Chad Basin)?

    NASA Astrophysics Data System (ADS)

    Diaz, Nathalie; Dietrich, Fabienne; Cailleau, Guillaume; Sebag, David; Ngounou Ngatcha, Benjamin; Verrecchia, Eric P.

    2016-05-01

    Non-anthropogenic earth mounds, defined as mima-like mounds in this study, have recently been observed in non-carbonate watersheds along the Sudano-Sahelian belt in the Chad Basin. In the Diamare piedmont (northern Cameroon) they are particularly well developed within stream networks. In less eroded areas, they occur as whaleback, flattened morphologies, or even as buried features. All these shapes are composed of clay-rich sediment associated with high proportions of secondary carbonate nodules and Fesbnd Mn micro-nodules. Their soil structure is prismatic to massive and vertical cracks are observed locally. Grain-size distributions emphasize the clay-rich nature of the sediment, with average clay contents of 32% ± 12.8% (n = 186), which is significantly higher than the clay content in the adjacent sediments in the landscape (mean = 10% ± 4%, n = 21). Moreover, high proportions of smectite characterize the soil, with average contents of 34 ± 7% (n = 25). At the micro-scale, the groundmass has a cross-striated b-fabric, with embedded smooth subangular quartz and feldspar grains of the silt-size fraction. All the characteristics point to altered vertic properties in the clay-rich sediment composing the mima-like mounds. Mima-like mounds are thus interpreted as degraded Vertisols. Compared to present-day Vertisols occurring in the piedmont, mima-like mounds are located upstream. It is thus proposed that the Vertisol areas were more extensive during a former and wetter period than the present-day. Subsequent changing climatic conditions increased erosion, revealing the gilgai micro-relief by preferential erosion in micro-lows rather than in micro-highs. Mima-like mounds of the Chad Basin might thus result from pedogenesis combined with later erosion. These local processes can be inherited from regional climatic variations during the Late Pleistocene-Holocene and likely be related to the African Humid Period.

  1. Pre-Columbian landscape impact and agriculture in the Monumental Mound region of the Llanos de Moxos, lowland Bolivia

    NASA Astrophysics Data System (ADS)

    Whitney, Bronwen S.; Dickau, Ruth; Mayle, Francis E.; Soto, J. Daniel; Iriarte, José

    2013-09-01

    We present a multiproxy study of land use by a pre-Columbian earth mounds culture in the Bolivian Amazon. The Monumental Mounds Region (MMR) is an archaeological sub-region characterized by hundreds of pre-Columbian habitation mounds associated with a complex network of canals and causeways, and situated in the forest-savanna mosaic of the Llanos de Moxos. Pollen, phytolith, and charcoal analyses were performed on a sediment core from a large lake (14 km2), Laguna San José (14°56.97'S, 64°29.70'W). We found evidence of high levels of anthropogenic burning from AD 400 to AD 1280, corroborating dated occupation layers in two nearby excavated habitation mounds. The charcoal decline pre-dates the arrival of Europeans by at least 100 yr, and challenges the notion that the mounds culture declined because of European colonization. We show that the surrounding savanna soils were sufficiently fertile to support crops, and the presence of maize throughout the record shows that the area was continuously cultivated despite land-use change at the end of the earth mounds culture. We suggest that burning was largely confined to the savannas, rather than forests, and that pre-Columbian deforestation was localized to the vicinity of individual habitation mounds, whereas the inter-mound areas remained largely forested.

  2. Relict nebkhas (pimple mounds) record prolonged late Holocene drought in the forested region of south-central United States

    NASA Astrophysics Data System (ADS)

    Seifert, Christopher L.; Cox, Randel Tom; Forman, Steven L.; Foti, Tom L.; Wasklewicz, Thad A.; McColgan, Andrew T.

    2009-05-01

    The origin and significance of pimple mounds (low, elliptical to circular dune-like features found across much of the south-central United States) have been debated for nearly two centuries. We cored pimple mounds at four sites spanning the Ozark Plateau, Arkansas River Valley, and Gulf of Mexico Coastal Plain and found that these mounds have a regionally consistent textural asymmetry such that there is a significant excess of coarse-grained sediment within their northwest flanks. We interpret this asymmetry as evidence of an eolian depositional origin of these mounds and conclude they are relict nebkhas (coppice dunes) deposited during protracted middle to late Holocene droughts. These four mounds yield optically stimulated luminescence ages between 2400 and 700 yr that correlate with well-documented periods of eolian activity and droughts on the southern Great Plains, including the Medieval Climate Anomaly. We conclude vegetation loss during extended droughts led to local eolian deflation and pimple mound deposition. These mounds reflect landscape response to multi-decadal droughts for the south-central U.S. The spatial extent of pimple mounds across this region further underscores the severity and duration of late Holocene droughts, which were significantly greater than historic droughts.

  3. Subsurface microbiology and biogeochemistry of a deep, cold-water carbonate mound from the Porcupine Seabight (IODP Expedition 307)

    PubMed Central

    Webster, Gordon; Blazejak, Anna; Cragg, Barry A; Schippers, Axel; Sass, Henrik; Rinna, Joachim; Tang, Xiaohong; Mathes, Falko; Ferdelman, Timothy G; Fry, John C; Weightman, Andrew J; Parkes, R John

    2009-01-01

    The Porcupine Seabight Challenger Mound is the first carbonate mound to be drilled (∼270 m) and analyzed in detail microbiologically and biogeochemically. Two mound sites and a non-mound Reference site were analyzed with a range of molecular techniques [catalyzed reporter deposition-fluorescence in situ hybridization (CARD-FISH), quantitative PCR (16S rRNA and functional genes, dsrA and mcrA), and 16S rRNA gene PCR-DGGE] to assess prokaryotic diversity, and this was compared with the distribution of total and culturable cell counts, radiotracer activity measurements and geochemistry. There was a significant and active prokaryotic community both within and beneath the carbonate mound. Although total cell numbers at certain depths were lower than the global average for other subseafloor sediments and prokaryotic activities were relatively low (iron and sulfate reduction, acetate oxidation, methanogenesis) they were significantly enhanced compared with the Reference site. In addition, there was some stimulation of prokaryotic activity in the deepest sediments (Miocene, > 10 Ma) including potential for anaerobic oxidation of methane activity below the mound base. Both Bacteria and Archaea were present, with neither dominant, and these were related to sequences commonly found in other subseafloor sediments. With an estimate of some 1600 mounds in the Porcupine Basin alone, carbonate mounds may represent a significant prokaryotic subseafloor habitat. PMID:18826439

  4. Overview of the earth mounded concrete bunker prototype license application project: Objectives and approach

    SciTech Connect

    Conner, J.E.

    1989-11-01

    This paper presents an overview of the objectives and approach taken in developing the Earth-mounded Concrete Bunker Prototype License Application Project. The Prototype License Application Project was initiated by the Department of Energy`s National Low-Level Waste Management Program in early 1987 and completed in November 1988. As part of this project a prototype safety analysis report was developed. The safety analysis report evaluates the licensibility of an earth-mounded concrete bunker for a low-level radioactive waste (LLW) disposal facility located on a hypothetical site in the northeastern United States. The project required approximately five person-years and twenty months to develop.

  5. CFD Growth of 3C-SiC on 4H/6H Mesas

    NASA Technical Reports Server (NTRS)

    Neudeck, Philip G.; Trunek, Andrew J.; Spry, David J.; Powell, J. Anthony; Du, Hui; Skowronski, Marek; Huang, XianRong; Dudley, Michael

    2006-01-01

    This article describes growth and characterization of the highest quality reproducible 3C-SiC heteroepitaxial films ever reported. By properly nucleating 3C-SiC growth on top of perfectly on-axis (0001) 4H-SiC mesa surfaces completely free of atomic scale steps and extended defects, growth of 3C-SiC mesa heterofilms completely free of extended crystal defects can be achieved. In contrast, nucleation and growth of 3C-SiC mesa heterofilms on top of 4H-SiC mesas with atomic-scale steps always results in numerous observable dislocations threading through the 3C-SiC epilayer. High-resolution X-ray diffraction and transmission electron microscopy measurements indicate non-trivial in-plane lattice mismatch between the 3C and 4H layers. This mismatch is somewhat relieved in the step-free mesa case via misfit dislocations confined to the 3C/4H interfacial region without dislocations threading into the overlying 3C-SiC layer. These results indicate that the presence or absence of steps at the 3C/4H heteroepitaxial interface critically impacts the quality, defect structure, and relaxation mechanisms of single-crystal heteroepitaxial 3C-SiC films.

  6. Existence of {sub {lambda}}{sub {lambda}}{sup 4}H: A variational Monte Carlo search

    SciTech Connect

    Shoeb, Mohammad

    2005-02-01

    A variational Monte Carlo (VMC) calculation for the binding energy B{sub {lambda}}{sub {lambda}} of the lightest hypernucleus {sub {lambda}}{sub {lambda}}{sup 4}H has been performed in the four-body {lambda}{lambda}pn model. A range of input {lambda}{lambda} potentials of moderate strength produce a particle-stable {sub {lambda}}{sub {lambda}}{sup 4}H for the simulated NSC97e and f {lambda}N potentials, whereas the phenomenological Minnesota {lambda}N potential needs a much stronger {lambda}{lambda} potential to bind. The VMC results for B{sub {lambda}}{sub {lambda}} agree with the prediction of the stochastic variational model but contradict the recent Faddeev-Yakubovsky calculation. As reported earlier, B{sub {lambda}}{sub {lambda}} is sensitive to the triplet {lambda}N channel for a given {lambda}{lambda} potential. The B{sub {lambda}}{sub {lambda}} of {sub {lambda}}{sub {lambda}}{sup 4}H in the three-body {lambda}{lambda}d cluster model is consistent with but slightly lower than the Faddeev calculation. The VMC method predicts a stable {sub {lambda}}{sub {lambda}}{sup 4}H system in both models and thus offers the possibility of identifying {sub {lambda}}{sub {lambda}}{sup 4}H in a future extension of E906 or of a related experiment at KEK, provided the simulated potentials are true representations of realistic Nijmegen potentials.

  7. CVD Growth of 3C-SiC on 4H/6H Mesas

    SciTech Connect

    Neudeck,P.; Trunek, A.; Spry, D.; Powell, J.; Du, H.; Skowronski, M.; Huang, X.; Dudley, M.

    2006-01-01

    This article describes growth and characterization of the highest quality reproducible 3C-SiC heteroepitaxial films ever reported. By properly nucleating 3C-SiC growth on top of perfectly on-axis (0001) 4H-SiC mesa surfaces completely free of atomic scale steps and extended defects, growth of 3C-SiC mesa heterofilms completely free of extended crystal defects can be achieved. In contrast, nucleation and growth of 3C-SiC mesa heterofilms on top of 4H-SiC mesas with atomic-scale steps always results in numerous observable dislocations threading through the 3C-SiC epilayer. High-resolution X-ray diffraction (HRXRD) and high resolution cross-sectional transmission electron microscopy (HRXTEM) measurements indicate non-trivial, in-plane, lattice mismatch between the 3C and 4H layers. This mismatch is somewhat relieved in the step-free mesa case via misfit dislocations confined to the 3C/4H interfacial region without dislocations threading into the overlying 3C-SiC layer. These results indicate that the presence or absence of steps at the 3C/4H heteroepitaxial interface critically impacts the quality, defect structure, and relaxation mechanisms of single-crystal heteroepitaxial 3C-SiC films.

  8. Effect of neutron irradiation on charge collection efficiency in 4H-SiC Schottky diode

    NASA Astrophysics Data System (ADS)

    Wu, Jian; Jiang, Yong; Lei, Jiarong; Fan, Xiaoqiang; Chen, Yu; Li, Meng; Zou, Dehui; Liu, Bo

    2014-01-01

    The charge collection efficiency (CCE) in 4H-SiC Schottky diode is studied as a function of neutron fluence. The 4H-SiC diode was irradiated with fast neutrons of a critical assembly in Nuclear Physics and Chemistry Institute and CCE for 3.5 MeV alpha particles was then measured as a function of the applied reverse bias. It was found from our experiment that an increase of neutron fluence led to a decrease of CCE. In particular, CCE of the diode was less than 1.3% at zero bias after an irradiation at 8.26×1014 n/cm2. A generalized Hecht's equation was employed to analyze CCE in neutron irradiated 4H-SiC diode. The calculations nicely fit the CCE of 4H-SiC diode irradiated at different neutron fluences. According to the calculated results, the extracted electron μτ product (μτ)e and hole μτ product (μτ)h of the irradiated 4H-SiC diode are found to decrease by increasing the neutron fluence.

  9. Physiological and Biogeochemical Traits of Bleaching and Recovery in the Mounding Species of Coral Porites lobata: Implications for Resilience in Mounding Corals

    PubMed Central

    Levas, Stephen J.; Grottoli, Andréa G.; Hughes, Adam; Osburn, Christopher L.; Matsui, Yohei

    2013-01-01

    Mounding corals survive bleaching events in greater numbers than branching corals. However, no study to date has determined the underlying physiological and biogeochemical trait(s) that are responsible for mounding coral holobiont resilience to bleaching. Furthermore, the potential of dissolved organic carbon (DOC) as a source of fixed carbon to bleached corals has never been determined. Here, Porites lobata corals were experimentally bleached for 23 days and then allowed to recover for 0, 1, 5, and 11 months. At each recovery interval a suite of analyses were performed to assess their recovery (photosynthesis, respiration, chlorophyll a, energy reserves, tissue biomass, calcification, δ13C of the skeletal, δ13C, and δ15N of the animal host and endosymbiont fractions). Furthermore, at 0 months of recovery, the assimilation of photosynthetically acquired and zooplankton-feeding acquired carbon into the animal host, endosymbiont, skeleton, and coral-mediated DOC were measured via 13C-pulse-chase labeling. During the first month of recovery, energy reserves and tissue biomass in bleached corals were maintained despite reductions in chlorophyll a, photosynthesis, and the assimilation of photosynthetically fixed carbon. At the same time, P. lobata corals catabolized carbon acquired from zooplankton and seemed to take up DOC as a source of fixed carbon. All variables that were negatively affected by bleaching recovered within 5 to 11 months. Thus, bleaching resilience in the mounding coral P. lobata is driven by its ability to actively catabolize zooplankton-acquired carbon and seemingly utilize DOC as a significant fixed carbon source, facilitating the maintenance of energy reserves and tissue biomass. With the frequency and intensity of bleaching events expected to increase over the next century, coral diversity on future reefs may favor not only mounding morphologies but species like P. lobata, which have the ability to utilize heterotrophic sources of fixed carbon

  10. Physiological and biogeochemical traits of bleaching and recovery in the mounding species of coral Porites lobata: implications for resilience in mounding corals.

    PubMed

    Levas, Stephen J; Grottoli, Andréa G; Hughes, Adam; Osburn, Christopher L; Matsui, Yohei

    2013-01-01

    Mounding corals survive bleaching events in greater numbers than branching corals. However, no study to date has determined the underlying physiological and biogeochemical trait(s) that are responsible for mounding coral holobiont resilience to bleaching. Furthermore, the potential of dissolved organic carbon (DOC) as a source of fixed carbon to bleached corals has never been determined. Here, Porites lobata corals were experimentally bleached for 23 days and then allowed to recover for 0, 1, 5, and 11 months. At each recovery interval a suite of analyses were performed to assess their recovery (photosynthesis, respiration, chlorophyll a, energy reserves, tissue biomass, calcification, δ(13)C of the skeletal, δ(13)C, and δ(15)N of the animal host and endosymbiont fractions). Furthermore, at 0 months of recovery, the assimilation of photosynthetically acquired and zooplankton-feeding acquired carbon into the animal host, endosymbiont, skeleton, and coral-mediated DOC were measured via (13)C-pulse-chase labeling. During the first month of recovery, energy reserves and tissue biomass in bleached corals were maintained despite reductions in chlorophyll a, photosynthesis, and the assimilation of photosynthetically fixed carbon. At the same time, P. lobata corals catabolized carbon acquired from zooplankton and seemed to take up DOC as a source of fixed carbon. All variables that were negatively affected by bleaching recovered within 5 to 11 months. Thus, bleaching resilience in the mounding coral P. lobata is driven by its ability to actively catabolize zooplankton-acquired carbon and seemingly utilize DOC as a significant fixed carbon source, facilitating the maintenance of energy reserves and tissue biomass. With the frequency and intensity of bleaching events expected to increase over the next century, coral diversity on future reefs may favor not only mounding morphologies but species like P. lobata, which have the ability to utilize heterotrophic sources of

  11. Nickel ohmic contacts of high-concentration P-implanted 4H-SiC

    NASA Astrophysics Data System (ADS)

    Chunjuan, Liu; Su, Liu; Jingjing, Feng; Rong, Wu

    2012-03-01

    Different-dose phosphorus ion implantation into 4H-SiC followed by high-temperature annealing was investigated. AlN/BN and graphite post-implantation annealing for ion-implanted SiC at 1650 °C for 30 min was conducted to electrically activate the implanted P+ ions. Ni contacts to the P+-implanted 4H-SiC layers were examined by transmission line model and Hall measurements fabricated on P-implanted (0001). The results indicated that a high-quality ohmic contact and specific contact resistivity of 1.30 × 10-6 Ω · cm2 was obtained for the P+-implanted 4H-SiC layers. The ρC values of the Ni-based implanted layers decreased with increasing P doping concentrations, and a weaker temperature dependence was observed for different samples in the 200-500 K temperature range.

  12. Termite mound emissions of CH4 and CO2 are primarily determined by seasonal changes in termite biomass and behaviour.

    PubMed

    Jamali, Hizbullah; Livesley, Stephen J; Dawes, Tracy Z; Hutley, Lindsay B; Arndt, Stefan K

    2011-10-01

    Termites are a highly uncertain component in the global source budgets of CH(4) and CO(2). Large seasonal variations in termite mound fluxes of CH(4) and CO(2) have been reported in tropical savannas but the reason for this is largely unknown. This paper investigated the processes that govern these seasonal variations in CH(4) and CO(2) fluxes from the mounds of Microcerotermes nervosus Hill (Termitidae), a common termite species in Australian tropical savannas. Fluxes of CH(4) and CO(2) of termite mounds were 3.5-fold greater in the wet season as compared to the dry season and were a direct function of termite biomass. Termite biomass in mound samples was tenfold greater in the wet season compared to the dry season. When expressed per unit termite biomass, termite fluxes were only 1.2 (CH(4)) and 1.4 (CO(2))-fold greater in the wet season as compared to the dry season and could not explain the large seasonal variations in mound fluxes of CH(4) and CO(2). Seasonal variation in both gas diffusivity through mound walls and CH(4) oxidation by mound material was negligible. These results highlight for the first time that seasonal termite population dynamics are the main driver for the observed seasonal differences in mound fluxes of CH(4) and CO(2). These findings highlight the need to combine measurements of gas fluxes from termite mounds with detailed studies of termite population dynamics to reduce the uncertainty in quantifying seasonal variations in termite mound fluxes of CH(4) and CO(2).

  13. Differences between bacterial communities in the gut of a soil-feeding termite (Cubitermes niokoloensis) and its mounds.

    PubMed

    Fall, Saliou; Hamelin, Jérôme; Ndiaye, Farma; Assigbetse, Komi; Aragno, Michel; Chotte, Jean Luc; Brauman, Alain

    2007-08-01

    In tropical ecosystems, termite mound soils constitute an important soil compartment covering around 10% of African soils. Previous studies have shown (S. Fall, S. Nazaret, J. L. Chotte, and A. Brauman, Microb. Ecol. 28:191-199, 2004) that the bacterial genetic structure of the mounds of soil-feeding termites (Cubitermes niokoloensis) is different from that of their surrounding soil. The aim of this study was to characterize the specificity of bacterial communities within mounds with respect to the digestive and soil origins of the mound. We have compared the bacterial community structures of a termite mound, termite gut sections, and surrounding soil using PCR-denaturing gradient gel electrophoresis (DGGE) analysis and cloning and sequencing of PCR-amplified 16S rRNA gene fragments. DGGE analysis revealed a drastic difference between the genetic structures of the bacterial communities of the termite gut and the mound. Analysis of 266 clones, including 54 from excised bands, revealed a high level of diversity in each biota investigated. The soil-feeding termite mound was dominated by the Actinobacteria phylum, whereas the Firmicutes and Proteobacteria phyla dominate the gut sections of termites and the surrounding soil, respectively. Phylogenetic analyses revealed a distinct clustering of Actinobacteria phylotypes between the mound and the surrounding soil. The Actinobacteria clones of the termite mound were diverse, distributed among 10 distinct families, and like those in the termite gut environment lightly dominated by the Nocardioidaceae family. Our findings confirmed that the soil-feeding termite mound (C. niokoloensis) represents a specific bacterial habitat in the tropics.

  14. Synthesis, antifungal activity and docking study of 2-amino-4H-benzochromene-3-carbonitrile derivatives

    NASA Astrophysics Data System (ADS)

    Mirjalili, BiBi Fatemeh; Zamani, Leila; Zomorodian, Kamiar; Khabnadideh, Soghra; Haghighijoo, Zahra; Malakotikhah, Zahra; Ayatollahi Mousavi, Seyyed Amin; Khojasteh, Shaghayegh

    2016-07-01

    Pathogenic fungi are associated with diseases ranging from simple dermatosis to life-threatening infections, particularly in immunocompromised patients. During the past two decades, resistance to established antifungal drugs has increased dramatically and has made it crucial to identify novel antimicrobial compounds. Here, we selected 12 new compounds of 2-amino-4H-benzochromene-3-carbonitrile drivetives (C1-C12) for synthesis by using nano-TiCl4.SiO2 as efficient and green catalyst, then nine of synthetic compounds were evaluated against different species of fungi, positive gram and negative gram of bacteria. Standard and clinical strains of antibiotics sensitive and resistant fungi and bacteria were cultured in appropriate media. Biological activity of the 2-amino-4H-benzochromene-3-carbonitrile derivatives against fungi and bacteries were estimated by the broth micro-dilution method as recommended by clinical and laboratory standard institute (CLSI). In addition minimal fangicidal and bactericial concenteration of the compounds were also determined. Considering our results showed that compound 2-amino-4-(4-methyl benzoate)-4H-benzo[f]chromen-3-carbonitrile (C9) had the most antifungal activity against Aspergillus clavatus, Candida glabarata, Candida dubliniensis, Candida albicans and Candida tropicalis at concentrations ranging from 8 to ≤128 μg/mL. Also compounds 2-amino-4-(3,4-dimethoxyphenyl)-4H-benzo[f]chromen-3-carbonitrile (C4) and 2-amino-4-(4-isopropylphenyl)-4H-benzo[f]chromen-3-carbonitrile (C3) had significant inhibitory activities against Epidermophyton floccosum following 2-amino-4-(4-methylbenzoate)-4H-benzo[f]chromen-3-carbonitrile (C9), respectively. Docking simulation was performed to insert compounds C3, C4 and C9 in to CYP51 active site to determine the probable binding model.

  15. Adult volunteerism in Pennsylvania 4-H natural resources programs for youth

    NASA Astrophysics Data System (ADS)

    Smith, Sanford Sherrick

    2001-07-01

    Pennsylvania's 4-H Youth Development Program relies on adult volunteers to reach youth with educational information and opportunities. Finding adults willing to do this volunteer work is challenging. This study looks at the current status of adult volunteerism with natural resources 4-H projects, and seeks to understand potential volunteers. The literature has much to offer in regards to general volunteer trends, management, motivations, and task preferences; however, few studies focus on volunteers in natural resources or environmental education. A telephone survey conducted with county 4-H agents revealed that only 3.2% of Pennsylvania's 4-H volunteers work with natural resources projects in 56 out of 67 counties, and that very few volunteers have any formal background in natural resources. Semi-structured interviews with 41 adult volunteers currently working with natural resources projects explored volunteer demographics, history, program design preferences, and ideas for seeking more volunteers. Findings from the telephone survey and the semi-structured interviews were used to generate a mail survey with large, random samples from three population groups: (1) 4-H Volunteers, (2) 4-H Parents, and (3) Natural Resources Professionals. Confidence with youth and subject matter, and adult willingness to volunteer was explored for each of the groups in relation to background, demographic characteristics, motivational needs, past and present volunteer activity, personal interests, and program design importance. Natural resources subject matter confidence was shown to be the most significant variable determining willingness to volunteer for all three groups. The variables that contributed to subject matter and youth confidence varied for each population. Key variables effecting willingness to volunteer included outdoor activity level, personal interest in natural resources, the need to fulfill feelings of social responsibility, and confidence with youth. Program design

  16. Anti-reflective nano- and micro-structures on 4H-SiC for photodiodes

    PubMed Central

    2011-01-01

    In this study, nano-scale honeycomb-shaped structures with anti-reflection properties were successfully formed on SiC. The surface of 4H-SiC wafer after a conventional photolithography process was etched by inductively coupled plasma. We demonstrate that the reflection characteristic of the fabricated photodiodes has significantly reduced by 55% compared with the reference devices. As a result, the optical response Iillumination/Idark of the 4H-SiC photodiodes were enhanced up to 178%, which can be ascribed primarily to the improved light trapping in the proposed nano-scale texturing. PMID:21711744

  17. Crystal and molecular structure of 2,4,4-trisubstituted 5-amino-4 H-imidazoles

    NASA Astrophysics Data System (ADS)

    Bellanato, J.; Avendaño, C.; Ramos, M. T.; Smith-Verdier, P.; Florencio, F.; Garcia-Blanco, S.

    Three 5-amino-4 H-imidazole derivatives 2(2-pyridyl) and 2-ethoxycarbonyl-4,4-pentamethylene-5-amino-and 2(2-pyridyl)-4,4-dimethyl-5(2-pyridylamino)4 H-imidazoles have been studied by i.r. and Raman spectroscopy. The crystal structure of one has been determined by X-ray diffraction. The tautomeric amino-imino equilibrium in different working conditions is also studied from spectroscopic data. The amino and the unconjugated imino forms are characterized.

  18. Estimation of negative ions in VHF SiH4/H2 plasma

    NASA Astrophysics Data System (ADS)

    Yamane, Tsukasa; Nakano, Shinya; Nakao, Sachiko; Takeuchi, Yoshiaki; Ichiki, Ryuta; Muta, Hiroshi; Uchino, Kiichiro; Kawai, Yoshinobu

    2014-11-01

    The characteristics of a VHF SiH4/H2 plasma (frequency: 60 MHz) at high pressures were examined as a function of silane concentration with a heated Langmuir probe. Anomalous reductions in electron saturation current were observed, suggesting the existence of many negative ions. An estimation of the concentration of negative ions was attempted using the sheath theory including negative ions. It was found that there exist H- and SiH3- ions as dominant negative ions in the VHF SiH4/H2 plasma. In addition, the measured floating potential agreed with the theoretical value.

  19. Classification Shell Game.

    ERIC Educational Resources Information Center

    Etzold, Carol

    1983-01-01

    Discusses shell classification exercises. Through keying students advanced from the "I know what a shell looks like" stage to become involved in the classification process: observing, labeling, making decisions about categories, and identifying marine animals. (Author/JN)

  20. The early diagenetic and PETROphysical behaviour of recent cold-water CARbonate mounds in Deep Environments (PETROCARDE)

    NASA Astrophysics Data System (ADS)

    Foubert, Anneleen; Pirlet, Hans; Thierens, Mieke; de Mol, Ben; Henriet, Jean-Pierre; Swennen, Rudy

    2010-05-01

    Sub-recent cold-water carbonate mounds localized in deeper slope settings on the Atlantic continental margins cannot be any longer neglected in the study of carbonate systems. They clearly play a major role in the dynamics of mixed siliciclastic-carbonate and/or carbonate-dominated continental slopes. Carbonate accumulation rates of cold-water carbonate mounds are about 4 to 12 % of the carbonate accumulation rates of tropical shallow-water reefs but exceed the carbonate accumulation rates of their slope settings by a factor of 4 to 12 (Titschack et al., 2009). These findings emphasize the importance of these carbonate factories as carbonate niches on the continental margins. The primary environmental architecture of such carbonate bodies is well-characterized. However, despite proven evidences of early diagenesis overprinting the primary environmental record (e.g. aragonite dissolution) (Foubert & Henriet, 2009), the extent of early diagenetic and biogeochemical processes shaping the petrophysical nature of mounds is until now not yet fully understood. Understanding (1) the functioning of a carbonate mound as biogeochemical reactor triggering early diagenetic processes and (2) the impact of early diagenesis on the petrophysical behaviour of a carbonate mound in space and through time are necessary (vital) for the reliable prediction of potential late diagenetic processes. Approaching the fossil carbonate mound record, through a profound study of recent carbonate bodies is innovative and will help to better understand processes observed in the fossil mound world (such as cementation, brecciation, fracturing, etc…). In this study, the 155-m high Challenger mound (Porcupine Seabight, SW of Ireland), drilled during IODP Expedition 307 aboard the R/V Joides Resolution (Foubert & Henriet, 2009), and mounds from the Gulf of Cadiz (Moroccan margin) will be discussed in terms of early diagenetic processes and petrophysical behaviour. Early differential diagenesis

  1. Managing for Motivation: Herzberg's Motivation-Hygiene Theory and Its Application to 4-H Leadership. National Intern Report.

    ERIC Educational Resources Information Center

    Freeman, Walter J.

    A study examined the organizational factors contributing to the motivation of 4-H volunteer leaders. A modified form of Herzberg's Motivation-Hygiene Theory served as the research design of the study. A total of 149 4-H leaders were interviewed regarding thirteen job factors: recognition; personal growth; relationships with other 4-H leaders,…

  2. Maine 4-H Afterschool Academy--A Professional Development Opportunity for Out-of-School-Time Providers

    ERIC Educational Resources Information Center

    Lobley, Jennifer; Ouellette, Kristy L.

    2013-01-01

    The Maine 4-H Afterschool Academy trained 369 after-school and out of school time providers in 2011. This easy-to-adapt professional development opportunity used blended learning, a combination of in-person and Web-based opportunities. Providers successfully learned concepts and practical knowledge regarding 4-H, specifically 4-H Science. In…

  3. Current Practices for Training Staff to Accommodate Youth with Special Health Care Needs in the 4-H Camp Setting

    ERIC Educational Resources Information Center

    Mouton, Lauren; Bruce, Jacklyn

    2013-01-01

    The theory of inclusion is the foundation for the study reported here; inclusion is a focus not only of formal education, but also of nonformal educational settings such as 4-H. Ideally, 4-H camps are designed to serve youth of all backgrounds and abilities. By accommodating youth with special health care needs, 4-H camps are effectively meeting…

  4. E-Learning for 4-H Volunteers: Who Uses It, and What Can We Learn from Them?

    ERIC Educational Resources Information Center

    Ouellette, Kristy L.; Lesmeister, Marilyn K.; Lobley, Jennifer; Gross, Kerry M.

    2014-01-01

    Orienting and training 4-H volunteers are critical to individuals and the organization. The two-part study reported here re-establishes the profile of the 4-H volunteer and evaluates both the format and content of e-Learning for 4-H Volunteers modules launched in 2006. Volunteers from seven states perceived that online modules made learning more…

  5. A large-scale middle Miocene carbonate (?) mound structure in the Norwegian-Danish Basin: evidence for hydrocarbon migration?

    NASA Astrophysics Data System (ADS)

    Andresen, K. J.; Clausen, O. R.; Huuse, M.

    2007-12-01

    A mounded structure has been observed in the Norwegian-Danish Basin about 10 km east of the Coffee Soil Fault outside the Central Graben and almost directly on top of the mid-Miocene unconformity. The mounded structure has been mapped using 3D seismic data; it consists of two culminations arranged in a triangular area; one is 1500 m long, 800 m wide and 70 m high while the other is 800 m long, 400 m wide and 30 m high. The composite mound comprises a volume of some 29 mio m3 and is characterised by a high positive reflection amplitude at the top, differential compaction as compared to the surrounding sediments and velocity pull up in underlying reflections. These observations indicate a high velocity fill with higher acoustic impedance and less compaction than that of the surrounding sediments, and the interior of the mounded structure has thus been interpreted as a relatively hard, coarse grained or well cemented sediment. The observed mound is an isolated feature and there have been no reports on any similar structures in the surrounding area. Several possible morphological mound-shaped features have been considered such as igneous and clastic intrusions and extrusions, mud volcanoes, contourites, turbidites and carbonate mounds. The succession below the mound shows no vertical disturbance such as seismic chimneys or deformation of layers, and this seems to exclude an extrusive origin, which most likely would have had some influence on the sedimentary succession. Investigation of the base reflection in the surrounding area shows no sign of any erosional features such as submarine channels and this appears to exclude an origin as a turbidite or contourite since these features often are associated with some kind of erosion. Large present day seismic chimneys have been found in close proximity to the mound along with numerous elongated pockmarks in the Miocene succession right above the mound. These observations indicate that the study area is highly influenced by

  6. Stable isotope sales: Mound Facility customer and shipment summaries, FY 1981

    SciTech Connect

    Ruwe, Jr, A H

    1982-10-01

    A listing is given of Mound Facility's sales of stable isotopes of noble gases, carbon, oxygen, nitrogen, chlorine, and sulfur for Fiscal Year 1981. Purchasers are listed alphabetically and are divided into domestic and foreign groups. A cross-reference index by location is included for domestic customers. Cross-reference listings by isotope purchased are included for all customers.

  7. Early Triassic calcimicrobial mounds and biostromes of the Nanpanjiang basin, south China

    NASA Astrophysics Data System (ADS)

    Lehrmann, Daniel J.

    1999-04-01

    Early Triassic framestones were discovered in the interior of an isolated, marine carbonate platform in the Nanpanjiang basin. The framestones occur in two horizons: (1) the lowermost Triassic (Griesbachian), as biostromes as much as 15 m thick, and (2) the upper part of the Lower Triassic (Smithian or Spathian) as isolated domal or inverted conical mounds as much as 1.5 m thick. The mounds and biostromes consist of a rigid calcimicrobial framework enclosing a network of internal cavities, 1 to 3 cm across, filled with peloidal-skeletal sediment. The framework is made of irregular-to-tufted masses of chambered-to-clotted micrite structures referable to Renalcis, a calcified coccoid cyanobacteria. The framework is reinforced by microbial induced micritic crusts as well as marine cement. Metazoan fossils within the framework include gastropods, bivalves, ostracodes, spirorbids, and brachiopods. The Early Triassic is widely considered to have been a global gap in reef and reef mound development. The global reef gap concept has formed the foundation of models of reef evolution and of the reorganization of reef ecosystems after the end-Permian extinction. These models should be revised to account for the existence of Early Triassic calcimicrobial mounds and biostromes discussed herein.

  8. Mapping the fluid flow of the Mariana Mounds ridge flank hydrothermal system: Pore water chemical tracers

    SciTech Connect

    Wheat, C.G.; McDuff, R.E.

    1995-05-10

    The authors present a conceptual model of fluid circulation in a ridge flank hydrothermal system, the Mariana Mounds. The model is based on chemical data from pore waters extracted from piston cores and from push cores collected by deep-sea research vessel Alvin in small, meter-sized mounds situated on a local topographic high. These mounds are located within a region of heat flow exceeding that calculated from a conductive model and are zones of strong pore water upflow. The authors have interpreted the chemical data with time-dependent transport-reaction models to estimate pore water velocities. In the mounds themselves pore water velocities reach several meters per year to kilometers per year. Within about 100 m from these zones of focused upflow velocities decrease to several centimeters per year up to tens of centimeters per year. A large area of low heat flow surrounds these heat flow and topographic highs, with upwelling pore water velocities less than 2 cm/yr. In some nearby cores, downwelling of bottom seawater is evident but at speeds less than 2 cm/yr. Downwelling through the sediments appears to be a minor source of seawater recharge to the basaltic basement. The authors conclude that the principal source of seawater recharge to basement is where basement outcrops exist, most likely a scarpt about 2-4 km to the east and southeast of the study area. 71 refs., 14 figs., 3 tabs.

  9. Cultural Symbolism behind the Architectural Design of Mounds Park All-Nations Magnet School.

    ERIC Educational Resources Information Center

    Pewewardy, Cornell; May, Paul G.

    1992-01-01

    The architectural design of Mounds Park All-Nations Magnet School (St. Paul, Minnesota) incorporates cultural symbols representing the Native American worldview and Medicine Wheel Circle beliefs, as well as design elements from aboriginal housing styles, and colors and sculptured elements that reinforce the relationship of nature to building. (SV)

  10. SEASONAL SHIFTS IN THE HYPERSPECTRAL CHARACTERIZATION OF IMPORTED FIRE ANT (HYMENOPTERA: FORMICIDAE) MOUND FEATURES IN TURFGRASS

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Safe, expedient, and cost-effective field- to landscape-scale treatments of imported fire ant (IFA) infestations require technological developments that exploit the use of remotely-sensed contrasting features to detect cryptic mounds in heavily-managed turfgrass. Ground-based implementation of hyper...

  11. Seasonal Shifts in the Hyperspectral Characterization of Imported Fire Ant (Hymenoptera: Formicidae) Mound Features in Turfgrass

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Safe, expedient, and cost-effective field- to landscape-scale treatments of imported fire ant (IFA) infestations require technological developments that exploit the use of remotely-sensed contrasting features to detect cryptic mounds in heavily-managed turfgrass. Ground-based implementation of hyper...

  12. Effects of simulated and natural rainfall on summer mound construction by imported fire ants (Hymenoptera: Formicidae)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Imported fire ant (Solenopsis richteri x invicta) mounds in northeastern Mississippi were subjected to four treatments from late July through early September, 2006: application of water (7.5 L) and placement of an inverted 19 L bucket on top; application of water only; application of an inverted buc...

  13. Marketing research for EE G Mound Applied Technologies' heat treatment process of high strength materials

    SciTech Connect

    Shackson, R.H.

    1991-10-09

    This report summarizes research conducted by ITI to evaluate the commercialization potential of EG G Mound Applied Technologies' heat treatment process of high strength materials. The remainder of the report describes the nature of demand for maraging steel, extent of demand, competitors, environmental trends, technology life cycle, industry structure, and conclusion. (JL)

  14. Massive Dissociation of Subsurface Gas Hydrates and Collapse of Gas Hydrate Mounds during the LGM in the Eastern Margin of Japan Sea: Evidence from Benthic Forams and U/Th ages of Authigenic Carbonates

    NASA Astrophysics Data System (ADS)

    Matsumoto, R.; Takeuchi, E.; Sanno, R.

    2008-12-01

    A number of gigantic methane plumes, ca. 600 m high, and massive blocks of gas hydrate, ca. 0.5 m x 1.0 m, have been observed on the Umitaka spur and Joetsu knoll, eastern margin of Japan Sea. Large pockmarks and mounds, ca. 0.5 km in diameter, develop on the spur and knoll. The mounds exhibit rough morphological features characterized by small valleys of 5m wide, steep cliffs, crater-like depressions of 10 m in diameter, and scattered carbonate nodules and crusts of various size and shape with occasional gas hydrate blocks and veins and gas venting. To the contrary, pockmarks are inactive, partly filled by well-stratified mud without any indication of gas venting. 2D and 3D seismic surveys have recognized widely distributed BSRs at around 150 mbsf over the spur and knoll. Seismic profiles delineated deep gas chimney structures below the pockmarks and mounds. Unusual pull-up structures within gas chimneys indicate massive accumulation of gas hydrate. All these findings are likely to suggest that massive hydrate deposits both in gas chimneys at depths and hydrate mounds on the spur and knoll were collapsed and floated up to the sea surface, leaving big holes (= pockmarks) on the seafloor. Quantitative analysis of foraminiferal assemblage has revealed that the well laminated, burrow-free 17 to 22 ka sediments are substantially barren for benthic forams but for unusual species which has been believed to survive under high methane environments. Shells of such a few benthic formas from around 20 ka sediments are anomalously depleted in C-13. U-Th ages of authigenic carbonates of CH4-induced carbonate nodules and crusts are likely to center around 20 ka. Above line of evidences all suggest that gas hydrate system was collapsed and methane fluxes were enhanced during the last glacial maximum (LGM), presumably due to low stand of sea level and pressure release. Broken gas hydrate blocks are expected to float up to the sea surface to supply significant amount of methane to

  15. Middle School Dropout? Enrollment Trends in the California 4-H Youth Development Program

    ERIC Educational Resources Information Center

    Russell, Stephen T.; Heck, Katherine E.

    2008-01-01

    There is a widespread belief that youth drop out of youth development programs during the middle school years. Alternative explanations for the smaller number of adolescent program participants have yet to be explored. We examine age trends in program enrollment using data from over 221,000 youth enrolled in the California 4-H Youth Development…

  16. Promoting the Essential Elements of 4-H Youth Development through an Experiential Learning Model

    ERIC Educational Resources Information Center

    Meyer, Shelley; Jones, Kenneth R.

    2015-01-01

    The purpose of the project reported here was to apply Experiential Learning Theory to a context involving middle and high school aged youth while assessing the four concepts (belonging, mastery, independence, and generosity) in relation to the 4-H youth development essential elements. The conclusions of the project's evaluation suggest…

  17. Performance statistics of the FORTRAN 4 /H/ library for the IBM system/360

    NASA Technical Reports Server (NTRS)

    Clark, N. A.; Cody, W. J., Jr.; Hillstrom, K. E.; Thieleker, E. A.

    1969-01-01

    Test procedures and results for accuracy and timing tests of the basic IBM 360/50 FORTRAN 4 /H/ subroutine library are reported. The testing was undertaken to verify performance capability and as a prelude to providing some replacement routines of improved performance.

  18. A Partnership Model for Training Episodic Environmental Stewardship 4-H Volunteers

    ERIC Educational Resources Information Center

    Young, Jane Chin; Alexander, Janice; Smith, Martin H.

    2013-01-01

    The Marin Environmental Stewardship pilot project demonstrates the potential for a partnership model that brings together external and internal collaborators to recruit and train episodic 4-H volunteers to meet environmental education needs within a community. The clientele served by the volunteers trained through the project was at-risk, urban…

  19. Formation of low-temperature cirrus from H2SO4/H2O aerosol droplets.

    PubMed

    Bogdan, A; Molina, M J; Sassen, K; Kulmala, M

    2006-11-23

    We present experimental results obtained with a differential scanning calorimeter (DSC) that indicate the small ice particles in low-temperature cirrus clouds are not completely solid but rather coated with an unfrozen H2SO4/H2O overlayer. Our results provide a new look on the formation, development, and microphysical properties of low-temperature cirrus clouds.

  20. The Value of 4-H Judging Teams--Missouri Dairy Judging Alumni Survey

    ERIC Educational Resources Information Center

    Deaver, Karla; Probert, Ted

    2016-01-01

    Former Missouri 4-H Dairy Judging Team members responded to a survey about life skills development and the value of the judging team experience. Results of the survey indicate that judging team experience was highly influential in the development of communication, public speaking, and presentation skills. Respondents also indicated that judging…

  1. Children and their 4-H animal projects: How children use science in agricultural activity

    NASA Astrophysics Data System (ADS)

    Emo, Kenneth Roy

    Many children are introduced to science through informal educational programs. 4-H, an educational youth program, has a history of introducing scientific practices into agriculture. The purpose of this ethnographically-driven case study is to examine how science informs the actions of children raising market animals in a 4-H project. For two years the researcher collected data on 4-H children with market animal projects. Observations, interviews, and artifacts gathered are interpreted using the framework of activity theory. This study provides evidence for how the context of an activity system influences individual actions. Rules developed by the organization guide the actions of children to incorporate physical and psychological tools of science into their project to achieve the object: producing animals of proper weight and quality to be competitive in the county fair. Children learn the necessary actions from a community of practitioners through which expertise is distributed. Children's learning is demonstrated by the way their participation in their project changes with time, from receiving assistance from others to developing expertise in which they provide assistance to others. The strength of this educational experience is how children apply specific tools of science in ways that provide meaning and relevancy to their 4-H activity.

  2. Determining Directions for Change in a County 4-H Youth Program: The Role of Evaluation.

    ERIC Educational Resources Information Center

    Braverman, Marc; And Others

    This paper describes the evaluation of the 4-H youth program (serving ages 9 through 19) in Yolo County, California. The paper concentrates on the first component of the evaluation plan, a telephone survey of community needs and perceptions regarding services for youth which was conducted in November, 1984. The originally perceived questions…

  3. The Big E (Energy). 4-H Leader's Guide for Units 2 & 3.

    ERIC Educational Resources Information Center

    Caldwell, William; And Others

    This leader's guide is designed for units 2 and 3 of the Nebraska 4-H Energy Project. The goals of the project are to: (1) help young people understand energy problems related to life styles; (2) use energy resources carefully; (3) guide members in choosing their own energy alternatives; and (4) to enjoy together the challenges and creativity of…

  4. Participant Comfort with and Application of Inquiry-Based Learning: Results from 4-H Volunteer Training

    ERIC Educational Resources Information Center

    Haugen, Heidi; Stevenson, Anne; Meyer, Rebecca L.

    2016-01-01

    This article explores how a one-time training designed to support learning transfer affected 4-H volunteers' comfort levels with the training content and how comfort levels, in turn, affected the volunteers' application of tools and techniques learned during the training. Results of a follow-up survey suggest that the training participants…

  5. Diastereoselectivity in prebiotically relevant 5(4H)-oxazolone-mediated peptide couplings.

    PubMed

    Beaufils, Damien; Danger, Grégoire; Boiteau, Laurent; Rossi, Jean-Christophe; Pascal, Robert

    2014-03-21

    A stereochemical study of a potentially prebiotic peptide-forming reaction was carried out as the first part of a systems chemistry investigation of potential paths for symmetry breaking. Substantial diastereomeric excesses result from a fast epimerization of the 5(4H)-oxazolone intermediate in aqueous solution.

  6. A Beach and Dune Community. 4-H Marine Science. Member's Guide. Activity I. MSp 1.

    ERIC Educational Resources Information Center

    Auburn Univ., AL. Cooperative Extension Service.

    The investigation in this booklet is designed to provide 4-H members with opportunities to identify common plants and animals found on beaches and sand dunes and to determine the role of the plants and animals in this community. Learners are provided with a picture of a hypothetical beach and sand dune and a list of organisms (included in the…

  7. 4-H Tractor Operator Program Teaches Employability Skills and Safety to Youth

    ERIC Educational Resources Information Center

    Barrett, Debra K.

    2013-01-01

    For Michigan State University Extension, the Berrien County 4-H Tractor Operator Program has provided tractor safety education to teens for over 30 years. The certification training satisfies current requirements for operation of a 20 PTO HP or greater agricultural tractor by 14- and 15-year-old youth employed on property "not" owned,…

  8. Bio-Security Proficiencies Project for Beginning Producers in 4-H

    ERIC Educational Resources Information Center

    Smith, Martin H.; Meehan, Cheryl L.; Borba, John A.

    2014-01-01

    Improving bio-security practices among 4-H members who raise and show project animals is important. Bio-security measures can reduce the risk of disease spread and mitigate potential health and economic risks of disease outbreaks involving animal and zoonotic pathogens. Survey data provided statistical evidence that the Bio-Security Proficiencies…

  9. Stakeholder Satisfaction with a 4-H Extension Program for Five- to Eight-Year-Old Children.

    ERIC Educational Resources Information Center

    Scheer, Scott D.; Lafontaine, Kenneth R.

    1999-01-01

    A 4-H K-2 program was evaluated by 277 parents, 144 volunteers, and 44 extension agents. These stakeholders believed the program was beneficial and effective in improving children's life skills (self-esteem, making friends, making choices, learning and physical skills). (SK)

  10. 4-H Chickquest: Connecting Agri-Science with STEM Standards in Urban Schools

    ERIC Educational Resources Information Center

    Horton, Robert L.; Krieger, Jackie; Halasa, Katrina

    2013-01-01

    While young students are more capable of scientific inquiry than previously believed, elementary school teachers are often inexperienced in and lack confidence with teaching science. ChickQuest is a 4-H-created embryology curriculum for third-graders that meets Ohio state science standards, teaches STEM skills, and promotes ongoing interaction…

  11. 4-H Horticulture Project Activity Guides. Leader's Guide and Units 1-3.

    ERIC Educational Resources Information Center

    Illinois Univ., Urbana. Cooperative Extension Service.

    This document, concerning the 4-H horticulture project, includes a leader's guide and three youth activity guides. The leader's guide can be used to plan group project meetings that are both fun and educational. Activities can be adapted to various age groups. The leader's guide includes basic information for growing plants indoors and outdoors,…

  12. The Big E (Energy). 4-H Leader's Guide [for Unit 1].

    ERIC Educational Resources Information Center

    Caldwell, William; And Others

    This guide is designed for leaders of the Nebraska 4-H Energy Project. The goals of the project are to: (1) help young people understand energy problems related to life styles; (2) use energy resources carefully; (3) guide members in choosing their own energy alternatives; and (4) enjoy together the challenges and creativity of finding energy…

  13. Pennsylvania Youth in Action: 4-H Community Development. Adult Leader's Guide.

    ERIC Educational Resources Information Center

    Pennsylvania State Univ., University Park. Dept. of Agricultural and Extension Education.

    Designed to assist leaders in their roles as catalysts, advisors, and resource persons for the Pennsylvania Youth in Action 4-H Community Development program, the guide provides complementary educational, craft, and recreation suggestions to enhance student workbooks for three community development activity units. The first section focuses on the…

  14. County Clustering for the California 4-H Youth Development Program: Impacts and Lessons Learned

    ERIC Educational Resources Information Center

    Subramaniam, Aarti; Dasher, Harry Steve; Young, Jane Chin

    2012-01-01

    In response to budgetary constraints, a new staffing structure, the Pilot Leadership Plan, was proposed for California's 4-H Youth Development Program. County clusters were formed, each led by a coordinator. The plan was piloted for 2 years to provide insight into how county clustering could support Extension staff to increase and enhance…

  15. 4H-SiC photodiode model for DC SPICE circuit simulation

    NASA Astrophysics Data System (ADS)

    Kociubiński, Andrzej; Duk, Mariusz; Korona, Mateusz; Muzyka, Krzysztof

    2015-09-01

    Technology, characterization and in particularly modeling of 4H-SiC photodiode have been presented in this paper. Modeling and simulation has been performed using PSPICE environment. Comparison of simulation with real results for electrical characteristic (I-V) of circular SiC photodiodes has been also presented.

  16. Bufexamac ameliorates LPS-induced acute lung injury in mice by targeting LTA4H

    PubMed Central

    Xiao, Qiang; Dong, Ningning; Yao, Xue; Wu, Dang; Lu, Yanli; Mao, Fei; Zhu, Jin; Li, Jian; Huang, Jin; Chen, Aifang; Huang, Lu; Wang, Xuehai; Yang, Guangxiao; He, Guangyuan; Xu, Yong; Lu, Weiqiang

    2016-01-01

    Neutrophils play an important role in the occurrence and development of acute lung injury (ALI). Leukotriene B4 (LTB4), a hydrolysis product of epoxide leukotriene A4 (LTA4) catalyzed by LTA4 hydrolase (LTA4H), is one of the most potent chemoattractants for neutrophil. Bufexamac is a drug widely used as an anti-inflammatory agent on the skin, however, the mechanism of action is still not fully understood. In this study, we found bufexamac was capable of specifically inhibiting LTA4H enzymatic activity and revealed the mode of interaction of bufexamac and LTA4H using X-ray crystallography. Moreover, bufexamac significantly prevented the production of LTB4 in neutrophil and inhibited the fMLP-induced neutrophil migration through inhibition of LTA4H. Finally, bufexamac significantly attenuated lung inflammation as reflected by reduced LTB4 levels and weakened neutrophil infiltration in bronchoalveolar lavage fluid from a lipopolysaccharide-induced ALI mouse model. In summary, our study indicates that bufexamac acts as an inhibitor of LTB4 biosynthesis and may have potential clinical applications for the treatment of ALI. PMID:27126280

  17. Endocrine Aspects of 4H Leukodystrophy: A Case Report and Review of the Literature

    PubMed Central

    Billington, Emma; Bernard, Geneviève; Gibson, William; Corenblum, Bernard

    2015-01-01

    Introduction. 4H leukodystrophy is an autosomal recessive RNA polymerase III-related leukodystrophy, characterized by hypomyelination, with or without hypodontia (or other dental abnormalities) and hypogonadotropic hypogonadism. Case Presentation. We describe a 28-year-old female who presented with primary amenorrhea at the age of 19. She had a history of very mild neurological and dental abnormalities. She was found to have hypogonadotropic hypogonadism, and magnetic resonance imaging of the brain showed hypomyelination. The diagnosis of 4H leukodystrophy was made. She was subsequently found to have mutations in the POLR3B gene, which encodes the second largest subunit of RNA polymerase III. She wished to become pregnant and failed to respond to pulsatile GnRH but achieved normal follicular growth and ovulation with subcutaneous gonadotropin therapy. Discussion. Patients with 4H leukodystrophy may initially present with hypogonadotropic hypogonadism, particularly if neurological and dental manifestations are subtle. Making the diagnosis has important implications for prognosis and management. Progressive neurologic deterioration is expected, and progressive endocrine dysfunction may occur. Patients with 4H leukodystrophy should be counseled about disease progression and about this disease's autosomal recessive inheritance pattern. In those who wish to conceive, ovulation induction may be achieved with subcutaneous gonadotropin therapy, but pulsatile GnRH does not appear to be effective. PMID:26113998

  18. South Carolina's Model for Initiating Hispanic 4-H Clubs

    ERIC Educational Resources Information Center

    Lippert, Robert; Rembert, Kellye

    2012-01-01

    Over the past 5 years, through the initiative of several county Extension agents, South Carolina 4-H has established a successful model for bringing Hispanic youth into our program. We have found the most effective method is to initiate contact and establish partnerships with the principals and ESOL instructors in the local schools. Through this…

  19. Louisiana 4-H Seeds of Service School Gardens: A Descriptive View

    ERIC Educational Resources Information Center

    Cater, Melissa; Fox, Janet; Fletcher, Bobby Jr.

    2012-01-01

    Louisiana 4-H Seeds of Service School Gardens, a K-12 Learn and Serve Grant program, provides a descriptive view of how school gardens along with classroom instruction link curriculum to outdoor classrooms. The purpose of the process evaluation was to describe curriculum implementation fidelity, reach of the gardening program to participants, use…

  20. Possession, Transportation, and Use of Firearms by Older Youth in 4-H Shooting Sports Programs

    ERIC Educational Resources Information Center

    White, David J.; Williver, S. Todd

    2014-01-01

    Thirty years ago we would think nothing of driving to school with a jackknife in our pocket or rifle in the gun rack. Since then, the practices of possessing, transporting, and using firearms have been limited by laws, rules, and public perception. Despite restrictions on youth, the Youth Handgun Safety Act does afford 4-H shooting sports members…

  1. Giant polygons and mounds in the lowlands of Mars: signatures of an ancient ocean?

    PubMed

    Oehler, Dorothy Z; Allen, Carlton C

    2012-06-01

    This paper presents the hypothesis that the well-known giant polygons and bright mounds of the martian lowlands may be related to a common process-a process of fluid expulsion that results from burial of fine-grained sediments beneath a body of water. Specifically, we hypothesize that giant polygons and mounds in Chryse and Acidalia Planitiae are analogous to kilometer-scale polygons and mud volcanoes in terrestrial, marine basins and that the co-occurrence of masses of these features in Chryse and Acidalia may be the signature of sedimentary processes in an ancient martian ocean. We base this hypothesis on recent data from both Earth and Mars. On Earth, 3-D seismic data illustrate kilometer-scale polygons that may be analogous to the giant polygons on Mars. The terrestrial polygons form in fine-grained sediments that have been deposited and buried in passive-margin, marine settings. These polygons are thought to result from compaction/dewatering, and they are commonly associated with fluid expulsion features, such as mud volcanoes. On Mars, in Chryse and Acidalia Planitiae, orbital data demonstrate that giant polygons and mounds have overlapping spatial distributions. There, each set of features occurs within a geological setting that is seemingly analogous to that of the terrestrial, kilometer-scale polygons (broad basin of deposition, predicted fine-grained sediments, and lack of significant horizontal stress). Regionally, the martian polygons and mounds both show a correlation to elevation, as if their formation were related to past water levels. Although these observations are based on older data with incomplete coverage, a similar correlation to elevation has been established in one local area studied in detail with newer higher-resolution data. Further mapping with the latest data sets should more clearly elucidate the relationship(s) of the polygons and mounds to elevation over the entire Chryse-Acidalia region and thereby provide more insight into this

  2. Giant polygons and mounds in the lowlands of Mars: signatures of an ancient ocean?

    PubMed

    Oehler, Dorothy Z; Allen, Carlton C

    2012-06-01

    This paper presents the hypothesis that the well-known giant polygons and bright mounds of the martian lowlands may be related to a common process-a process of fluid expulsion that results from burial of fine-grained sediments beneath a body of water. Specifically, we hypothesize that giant polygons and mounds in Chryse and Acidalia Planitiae are analogous to kilometer-scale polygons and mud volcanoes in terrestrial, marine basins and that the co-occurrence of masses of these features in Chryse and Acidalia may be the signature of sedimentary processes in an ancient martian ocean. We base this hypothesis on recent data from both Earth and Mars. On Earth, 3-D seismic data illustrate kilometer-scale polygons that may be analogous to the giant polygons on Mars. The terrestrial polygons form in fine-grained sediments that have been deposited and buried in passive-margin, marine settings. These polygons are thought to result from compaction/dewatering, and they are commonly associated with fluid expulsion features, such as mud volcanoes. On Mars, in Chryse and Acidalia Planitiae, orbital data demonstrate that giant polygons and mounds have overlapping spatial distributions. There, each set of features occurs within a geological setting that is seemingly analogous to that of the terrestrial, kilometer-scale polygons (broad basin of deposition, predicted fine-grained sediments, and lack of significant horizontal stress). Regionally, the martian polygons and mounds both show a correlation to elevation, as if their formation were related to past water levels. Although these observations are based on older data with incomplete coverage, a similar correlation to elevation has been established in one local area studied in detail with newer higher-resolution data. Further mapping with the latest data sets should more clearly elucidate the relationship(s) of the polygons and mounds to elevation over the entire Chryse-Acidalia region and thereby provide more insight into this

  3. High efficiency 4H-SiC betavoltaic power sources using tritium radioisotopes

    NASA Astrophysics Data System (ADS)

    Thomas, Christopher; Portnoff, Samuel; Spencer, M. G.

    2016-01-01

    Realization of an 18.6% efficient 4H-silicon carbide (4H-SiC) large area betavoltaic power source using the radioisotope tritium is reported. A 200 nm 4H-SiC P+N junction is used to collect high-energy electrons. The electron source is a titanium tritide (TiH3x) foil, or an integrated titanium tritide region formed by the diffusion of tritium into titanium. The specific activity of the source is directly measured. Dark current measured under short circuit conditions was less than 6.1 pA/cm2. Samples measured with an external tritium foil produced an open circuit voltage of 2.09 V, short circuit current of 75.47 nA/cm2, fill factor of 0.86, and power efficiency of 18.6%. Samples measured with an integrated source produced power efficiencies of 12%. Simulations were done to determine the beta spectrum (modified by self absorption) exiting the source and the electron hole pair generation function in the 4H-SiC. The electron-hole pair generation function in 4H-SiC was modeled as a Gaussian distribution, and a closed form solution of the continuity equation was used to analyze the cell performance. The effective surface recombination velocity in our samples was found to be 105-106 cm/s. Our analysis demonstrated that the surface recombination dominates the performance of a tritium betavoltaic device but that using a thin P+N junction structure can mitigate some of the negative effects.

  4. Experimental Durability Testing of 4H SiC JFET Integrated Circuit Technology at 727 C

    NASA Technical Reports Server (NTRS)

    Spry, David; Neudeck, Phil; Chen, Liangyu; Chang, Carl; Lukco, Dorothy; Beheim, Glenn M

    2016-01-01

    We have reported SiC integrated circuits (IC's) with two levels of metal interconnect that have demonstrated prolonged operation for thousands of hours at their intended peak ambient operational temperature of 500 C [1, 2]. However, it is recognized that testing of semiconductor microelectronics at temperatures above their designed operating envelope is vital to qualification. Towards this end, we previously reported operation of a 4H-SiC JFET IC ring oscillator on an initial fast thermal ramp test through 727 C [3]. However, this thermal ramp was not ended until a peak temperature of 880 C (well beyond failure) was attained. Further experiments are necessary to better understand failure mechanisms and upper temperature limit of this extreme-temperature capable 4H-SiC IC technology. Here we report on additional experimental testing of custom-packaged 4H-SiC JFET IC devices at temperatures above 500 C. In one test, the temperature was ramped and then held at 727 C, and the devices were periodically measured until electrical failure was observed. A 4H-SiC JFET on this chip electrically functioned with little change for around 25 hours at 727 C before rapid increases in device resistance caused failure. In a second test, devices from our next generation 4H-SiC JFET ICs were ramped up and then held at 700 C (which is below the maximum deposition temperature of the dielectrics). Three ring oscillators functioned for 8 hours at this temperature before degradation. In a third experiment, an alternative die attach of gold paste and package lid was used, and logic circuit operation was demonstrated for 143.5 hours at 700 C.

  5. Testing the directed dispersal hypothesis: are native ant mounds (Formica sp.) favorable microhabitats for an invasive plant?

    PubMed

    Berg-Binder, Moni C; Suarez, Andrew V

    2012-07-01

    Ant-mediated seed dispersal may be a form of directed dispersal if collected seeds are placed in a favorable microhabitat (e.g., in or near an ant nest) that increases plant establishment, growth, and/or reproduction relative to random locations. We investigated whether the native ant community interacts with invasive leafy spurge (Euphorbia esula) in a manner consistent with predictions of the directed dispersal hypothesis. Resident ants quickly located and dispersed 60% of experimentally offered E. esula seeds. Additionally, 40% of seeds whose final deposition site was observed were either brought inside or placed on top of an ant nest. Seed removal was 100% when seeds were placed experimentally on foraging trails of mound-building Formica obscuripes, although the deposition site of these seeds is unknown. Natural density and above-ground biomass of E. esula were greater on Formica mound edges compared to random locations. However, seedling recruitment and establishment from experimentally planted E. esula seeds was not greater on mound edges than random locations 3 m from the mound. Soil from Formica mound edges was greater in available nitrogen and available phosphorus relative to random soil locations 3 m from the mound. These results suggest Formica ant mounds are favorable microhabitats for E. esula growth following seedling establishment, a likely consequence of nutrient limitation during plant growth. The results also indicate positive species interactions may play an important role in biological invasions.

  6. Human pharmacology of 3,4-methylenedioxymethamphetamine (MDMA, ecstasy) after repeated doses taken 4 h apart Human pharmacology of MDMA after repeated doses taken 4 h apart.

    PubMed

    Farré, Magí; Tomillero, Angels; Pérez-Mañá, Clara; Yubero, Samanta; Papaseit, Esther; Roset, Pere-Nolasc; Pujadas, Mitona; Torrens, Marta; Camí, Jordi; de la Torre, Rafael

    2015-10-01

    3,4-Methylenedioxymethamphetamine (MDMA, ecstasy) is a popular psychostimulant, frequently associated with multiple administrations over a short period of time. Repeated administration of MDMA in experimental settings induces tolerance and metabolic inhibition. The aim is to determine the acute pharmacological effects and pharmacokinetics resulting from two consecutive 100mg doses of MDMA separated by 4h. Ten male volunteers participated in a randomized, double-blind, crossover, placebo-controlled trial. The four conditions were placebo plus placebo, placebo plus MDMA, MDMA plus placebo, and MDMA plus MDMA. Outcome variables included pharmacological effects and pharmacokinetic parameters. After a second dose of MDMA, most effects were similar to those after a single dose, despite a doubling of MDMA concentrations (except for systolic blood pressure and reaction time). After repeated MDMA administration, a 2-fold increase was observed in MDMA plasma concentrations. For a simple dose accumulation MDMA and MDA concentrations were higher (+23.1% Cmax and +17.1% AUC for MDMA and +14.2% Cmax and +10.3% AUC for MDA) and HMMA and HMA concentrations lower (-43.3% Cmax and -39.9% AUC for HMMA and -33.2% Cmax and -35.1% AUC for HMA) than expected, probably related to MDMA metabolic autoinhibition. Although MDMA concentrations doubled after the second dose, most pharmacological effects were similar or slightly higher in comparison to the single administration, except for systolic blood pressure and reaction time which were greater than predicted. The pharmacokinetic-effects relationship suggests that when MDMA is administered at a 4h interval there exists a phenomenon of acute tolerance to its effects.

  7. Sub-kilometre (intra-crater) mounds in Utopia Planitia, Mars: character, occurrence and possible formation hypotheses

    NASA Astrophysics Data System (ADS)

    Soare, Richard J.; Conway, Susan J.; Pearce, Geoffrey D.; Costard, François; Séjourné, Antoine

    2013-08-01

    At the middle latitudes of Utopia Planitia (˜35-45°N; ˜65-101°E) hundreds of small-sized mounds located in sub-kilometre impact craters dot the landscape. Their shape varies from circular to crescentic and their height ranges from ˜10 to 50 m. Often, metre to decametre pitting is observed, as is metres-thick banding or stratification. Mound albedo is relatively high, i.e. ˜0.16. The plain's terrain in the region, previously linked to the latitude-dependent mantle (LDM) of ice-dust, displays pitting and albedo similar to the small intra-crater mounds. Some workers have suggested that the mounds and the plain's terrain share a common ice-dust origin. If so, then scrutinising the mounds could provide analogical insight on the key geological characteristics and spatial distribution of the LDM itself. Other workers have hypothesised that the mounds are eroded sedimentary landforms or periglacial mounds underlain by a perennial ice-core (closed-system pingos). In this article we develop and then discuss each of the three mound-hypotheses in a much more substantial manner than has been done hitherto. Towards this end we use high-resolution images, present a detailed regional-map of mound distribution and establish a regional platform of topographical analysis using MOLA data superposed on a large-scale CTX mosaic. Although the ice-dust hypothesis is consistent with some observations and measurements, we find that a (loess-based) sedimentary hypothesis shows greater plausibility. Of the three hypotheses evaluated, the pingo or periglacial one is the weakest.

  8. Fluctuating shells under pressure

    PubMed Central

    Paulose, Jayson; Vliegenthart, Gerard A.; Gompper, Gerhard; Nelson, David R.

    2012-01-01

    Thermal fluctuations strongly modify the large length-scale elastic behavior of cross-linked membranes, giving rise to scale-dependent elastic moduli. Whereas thermal effects in flat membranes are well understood, many natural and artificial microstructures are modeled as thin elastic shells. Shells are distinguished from flat membranes by their nonzero curvature, which provides a size-dependent coupling between the in-plane stretching modes and the out-of-plane undulations. In addition, a shell can support a pressure difference between its interior and its exterior. Little is known about the effect of thermal fluctuations on the elastic properties of shells. Here, we study the statistical mechanics of shape fluctuations in a pressurized spherical shell, using perturbation theory and Monte Carlo computer simulations, explicitly including the effects of curvature and an inward pressure. We predict novel properties of fluctuating thin shells under point indentations and pressure-induced deformations. The contribution due to thermal fluctuations increases with increasing ratio of shell radius to thickness and dominates the response when the product of this ratio and the thermal energy becomes large compared with the bending rigidity of the shell. Thermal effects are enhanced when a large uniform inward pressure acts on the shell and diverge as this pressure approaches the classical buckling transition of the shell. Our results are relevant for the elasticity and osmotic collapse of microcapsules. PMID:23150558

  9. Thermodynamic calculations in the system CH4-H2O and methane hydrate phase equilibria

    USGS Publications Warehouse

    Circone, S.; Kirby, S.H.; Stern, L.A.

    2006-01-01

    Using the Gibbs function of reaction, equilibrium pressure, temperature conditions for the formation of methane clathrate hydrate have been calculated from the thermodynamic properties of phases in the system CH4-H 2O. The thermodynamic model accurately reproduces the published phase-equilibria data to within ??2 K of the observed equilibrium boundaries in the range 0.08-117 MPa and 190-307 K. The model also provides an estimate of the third-law entropy of methane hydrate at 273.15 K, 0.1 MPa of 56.2 J mol-1 K-1 for 1/n CH4??H 2O, where n is the hydrate number. Agreement between the calculated and published phase-equilibria data is optimized when the hydrate composition is fixed and independent of the pressure and temperature for the conditions modeled. ?? 2006 American Chemical Society.

  10. Detection of minority carrier traps in p-type 4H-SiC

    SciTech Connect

    Alfieri, G.; Kimoto, T.

    2014-03-03

    Contrarily to the case of n-type 4H-SiC, very little is known about the presence of minority carrier traps in p-type epilayers. In this study, we performed the electrical characterization of as-grown, electron irradiated, and thermally oxidized p-type 4H-SiC, by using minority carrier transient spectroscopy. Four minority carrier traps are reported in 1.6–2.3 eV energy range above the valence band edge (E{sub V}). Particular emphasis is given to the mid-gap minority carrier trap (EH{sub 6∕7}) and to its correlation to an energetically close mid-gap majority carrier trap (HK4)

  11. Magnesium chloride tetrahydrate, MgCl2·4H2O.

    PubMed

    Schmidt, Horst; Hennings, Erik; Voigt, Wolfgang

    2012-01-01

    The title compound, MgCl(2)·4H(2)O, was crystallized at 403 K and its structure determined at 200 K. The structure is built up from MgCl(2)(H(2)O)(4) octahedra with a trans configuration. Each complex is situated on a crystallographic twofold axis, with the rotation axis aligned along one H(2)O-Mg-OH(2) axis. They are connected by a complex network of O-H···Cl hydrogen bonds. The structure contains two-dimensional sections that are essentially identical to those in the reported tetrahydrates of CrCl(2), FeCl(2), FeBr(2) and CoBr(2), but they are stacked in a different manner in MgCl(2)·4H(2)O compared with the transition metal structures.

  12. A 4H Silicon Carbide Gate Buffer for Integrated Power Systems

    SciTech Connect

    Ericson, N; Frank, S; Britton, C; Marlino, L; Ryu, SH; Grider, D; Mantooth, A; Francis, M; Lamichhane, R; Mudholkar, M; Shepherd, P; Glover, M; Valle-Mayorga, J; McNutt, T; Barkley, A; Whitaker, B; Cole, Z; Passmore, B; Lostetter, A

    2014-02-01

    A gate buffer fabricated in a 2-mu m 4H silicon carbide (SiC) process is presented. The circuit is composed of an input buffer stage with a push-pull output stage, and is fabricated using enhancement mode N-channel FETs in a process optimized for SiC power switching devices. Simulation and measurement results of the fabricated gate buffer are presented and compared for operation at various voltage supply levels, with a capacitive load of 2 nF. Details of the design including layout specifics, simulation results, and directions for future improvement of this buffer are presented. In addition, plans for its incorporation into an isolated high-side/low-side gate-driver architecture, fully integrated with power switching devices in a SiC process, are briefly discussed. This letter represents the first reported MOSFET-based gate buffer fabricated in 4H SiC.

  13. The C4H radical and the diffuse interstellar bands. An ab initio study

    NASA Technical Reports Server (NTRS)

    Kolbuszewski, Marcin

    1994-01-01

    An ab initio study of the low-lying electronic states of C4H has been presented where the species studied has a chi(2)sigma(+) ground state and two low lying pi states. Based on the vertical and adiabatic excitation energies between those states it is suggested that the 4428 A diffuse interstellar band is not carried by C4H. The application of the particle in a box model shows strong coincidences between the strong DIB's and predicted wavelengths of pi-pi transitions in C(2n)H series. Based on those coincidences, it is suggested the C(2n)H species as good candidates for carriers of diffuse interstellar bands.

  14. Donor-acceptor-pair emission in fluorescent 4H-SiC grown by PVT method

    SciTech Connect

    Liu, Xi Zhuo, Shi-Yi; Gao, Pan; Huang, Wei; Yan, Cheng-Feng; Shi, Er-Wei

    2015-04-15

    Fluorescent SiC, which contains donor and acceptor impurities with optimum concentrations, can work as a phosphor for visible light emission by donor-acceptor-pair (DAP) recombination. In this work, 3 inch N-B-Al co-doped fluorescent 4H-SiC crystals are prepared by PVT method. The p-type fluorescent 4H-SiC with low aluminum doping concentration can show intensive yellow-green fluorescence at room temperature. N-B DAP peak wavelength shifts from 578nm to 525nm and weak N-Al DAP emission occurred 403/420 nm quenches, when the temperature increases from 4K to 298K. The aluminum doping induces higher defect concentration in the fluorescent crystal and decreases optical transmissivity of the crystal in the visible light range. It triggers more non-radiative recombination and light absorption losses in the crystal.

  15. Characteristic morphologies of triangular defects on Si-face 4H-SiC epitaxial films

    NASA Astrophysics Data System (ADS)

    Yamashita, T.; Naijo, T.; Matsuhata, H.; Momose, K.; Osawa, H.; Okumura, H.

    2016-01-01

    Triangular defects with a characteristic morphology consisting of a 3C-type structure were investigated on Si-face 4H-SiC epitaxial films using electron microscopy. Two types of triangular defects were investigated: one with a single valley on the surface along the [ 11 2 bar 0 ] direction and another with several parallel ridges and valleys called "washboard-like defects". The defects with a single valley had a characteristic domain structure consisting of four 3C crystals, which is similar to that of previously reported comet-shaped defects on the C-face. It is shown that the 3C domain in the washboard-like defect is covered by 4H layers with a washboard-like morphology.

  16. Electric-field dependence of electron drift velocity in 4H-SiC

    NASA Astrophysics Data System (ADS)

    Ivanov, P. A.; Potapov, A. S.; Samsonova, T. P.; Grekhov, I. V.

    2016-09-01

    Room temperature isothermal forward current-voltage characteristics of mesa-epitaxial 4H-SiC Schottky diodes were measured at high electric fields (beyond 105 V/cm) in the 34-μm thick n-base doped at 1 × 1015 cm-3. The effect of diode self-heating on current was minimized when using single 4-ns pulses. The analytical formula was derived for the dependence of electron drift velocity on electric field along c-axis.

  17. Enantioselective synthesis of 4H-pyranonaphthoquinones via sequential squaramide and silver catalysis.

    PubMed

    Kaya, Uğur; Chauhan, Pankaj; Hack, Daniel; Deckers, Kristina; Puttreddy, Rakesh; Rissanen, Kari; Enders, Dieter

    2016-01-28

    An enantioselective one-pot Michael addition/hydroalkoxylation reaction between 2-hydroxy-1,4-naphthoquinones and alkyne-tethered nitroalkenes catalyzed by a cinchona-derived squaramide and a silver(I) salt has been developed. The sequential protocol provides a direct access to 4H-pyranonaphthoquinones in moderate to very good yields and good to excellent enantioselectivities at a very low catalyst loading (0.5 mol%) of the squaramide.

  18. Resistance of 4H-SiC Schottky barriers at high forward-current densities

    SciTech Connect

    Ivanov, P. A. Samsonova, T. P.; Il’inskaya, N. D.; Serebrennikova, O. Yu.; Kon’kov, O. I.; Potapov, A. S.

    2015-07-15

    The resistance of Schottky barriers based on 4H-SiC is experimentally determined at high forward-current densities. The measured resistance is found to be significantly higher than the resistance predicted by classical mechanisms of electron transport in Schottky contacts. An assumption concerning the crucial contribution of the tunnel-transparent intermediate oxide layer between the metal and semiconductor to the barrier resistance is proposed and partially justified.

  19. Polarographic study of cadmium 5-hydroxy 2-(hydroxymethyl) 4H-pyran-4-one complex

    NASA Technical Reports Server (NTRS)

    Wilson, Ray F.; Daniels, Robert C.

    1989-01-01

    A polarographic study was performed on the products formed in the interaction of cadmium (II) with a 5-hydroxy 2-(hydroxymethyl) 4H-Pyran-4-one, using varying conditions of pH, supporting electrolytes, and concentrations. Measurements using the differential pulse method show that cadmium (II) exhibits a molar combining ratio of complexing agents to cation ranging from 1 to 1 to 3 to 1 depending on the pH and the supporting electrolyte employed.

  20. Enantioselective synthesis of 4H-pyranonaphthoquinones via sequential squaramide and silver catalysis.

    PubMed

    Kaya, Uğur; Chauhan, Pankaj; Hack, Daniel; Deckers, Kristina; Puttreddy, Rakesh; Rissanen, Kari; Enders, Dieter

    2016-01-28

    An enantioselective one-pot Michael addition/hydroalkoxylation reaction between 2-hydroxy-1,4-naphthoquinones and alkyne-tethered nitroalkenes catalyzed by a cinchona-derived squaramide and a silver(I) salt has been developed. The sequential protocol provides a direct access to 4H-pyranonaphthoquinones in moderate to very good yields and good to excellent enantioselectivities at a very low catalyst loading (0.5 mol%) of the squaramide. PMID:26660230

  1. High Resolution Topography Analysis on Threading Edge Dislocations in 4H-SiC Epilayers

    SciTech Connect

    Kamata, I.; Nagano, M; Tsuchida, H; Chen, Y; Dudley, M

    2009-01-01

    Threading edge dislocations (TEDs) in a 4H-SiC epitaxial layer are investigated using high-resolution synchrotron topography. Six types of TED image are confirmed to correspond to the Burgers vector directions by a comparison of computer simulated images and observed topography images in crystal boundaries. Using a mapping method, a wide spatial distribution of the six types of TED is examined in a quarter section of a 2-inch wafer.

  2. Theoretical microwave spectral constants for C3H/+/ and C4H/+/

    NASA Technical Reports Server (NTRS)

    Wilson, S.; Green, S.

    1980-01-01

    A number of linear conjugated carbon chain molecules have been observed in the interstellar gas. It has been suggested that ion molecule chemistry schemes may explain the formation of these compounds. In the present paper, theoretical bond lengths and rotation constants are obtained for C3H(+) and C4H(+). Calculations for C3 are used to assess the accuracy of the former. Recent results for C2H(+) are examined.

  3. Isotopic Constraints on Sources and Benthic Turnover at Mound 12, Western Costa Rican Margin

    NASA Astrophysics Data System (ADS)

    Rehder, G.; Mau, S.; Linke, P.; Stange, K.

    2004-12-01

    During several expeditions, we investigated the emission and isotopic signature of methane at several mounds of the western continental margin off Costa Rica and Nicaragua. All of the mounds investigated, either created by mud volcanism or mud diapirism, show indications of fluid venting, including authigenic carbonates, chemoautotrophic consortia, salt depleted pore waters, and methane plumes in the water column. However, the amount of methane released as well as the stable carbon isotopic ratio (del C-13) vary considerably. Here we report on results from Mound 12, a mound with a very weak morphological expression; that is only 30 m high and elongated in northeast-southwest direction with diameters of about 1 to 1.6 km. Data were gathered using standard CTD/rosette equipment, a bottom water sampler enabling to resolve the methane distribution within the lowermost meter of the water column, a benthic chamber lander (BCL), multicorer and piston corer deployments. Data show a very light biogenic methane source (del C-13 < -90 permil within the sediments), -76 permil in the lowermost water samples with concentrations up to 100 nmo/L, and a methane background of - 45 permil 20 m above the vent site. High oxygen demand immediately at a site with bacterial mats in connection to lower carbon stable isotopic ratios with increasing sediment depth is in contrast to low oxygen demand and heavier stable isotopic ratios with increasing sediment depth only one meter apart. Moreover, the relation of methane concentration vs. isotopic signature above the vent sites implies considerable oxidation and fractionation in the benthic boundary layer (BBL) above the vent site, which is supported by some biomarker investigations at the same site. Significant oxidation of methane above vent sites within the BBL has not been reported so far. An alternative explanation, which is the existence of an additional methane source with an isotopic signature similar to the background ( del C-13 =-45

  4. Carbon-antisite vacancy defect in 4H silicon carbide for realizing solid state qubit

    NASA Astrophysics Data System (ADS)

    Gali, Adam; Szász, Krisztián; Ivády, Viktor; Abrikosov, Igor; Bockstedte, Michel; Janzén, Erik

    2015-03-01

    Dopants in solids are promising candidates for implementations of quantum bits for quantum computing. Silicon carbide (SiC) with engineered point defects is considered as very promising material for the next generation devices, with applications ranging from electronics and photonics to quantum computing. Employing density functional theory and many body perturbation theory, we show that the neutral carbon antisite-vacancy pair (CAV) has high spin ground state, and that its spin may be coherently manipulated by optical excitation in n-type 4H SiC. As the positively charged CAV defect in 4H SiC has been recently engineered to act as single photon source, our finding brings a hope that optically addressed quantum bits can be realized by the neutral CAV defects in 4H SiC, and provide an additional target for researchers seeking for solid state single color centers for quantum information processes and metrology. The calculated zero-phonon line of the optically excited state is about 1550 nm (0.8 eV) which perfectly fits to the telecom wavelengths, that makes this qubit candidate very promising for integration of quantum optics devices with existing fiber optics technology. Lendület program of Hungarian Academy of Sciences, the Knut & Alice Wallenberg Foundation, Swedish Research Council, US DoE.

  5. Combustion of CH4/H2/air mixtures in catalytic microreactors.

    PubMed

    Specchia, Stefania; Vella, Luigi D; Burelli, Sara; Saracco, Guido; Specchia, Vito

    2009-03-23

    The combustion of CH(4)/H(2)/HC mixtures in a very small space represents an alternative, innovative way to produce thermal/electrical energy. Pd/NiCrO(4) catalysts are lined on SiC monoliths via in situ solution combustion synthesis (SCS), and the monoliths are then tested by feeding CH(4), H(2), and lean CH(4)/H(2) mixtures into a lab-scale test rig at an output thermal power of 7.6 MW(th) m(-3). In all cases, the combustion temperature shifts to values lower than those observed in non-catalytic combustion. When the power density is kept constant (by adding H(2) to the gas mixture), the value of CH(4)-T(50) (the half-conversion temperature of CH(4)) decreases relative to that of pure CH(4), and the slope of the conversion curve becomes steeper. The higher the H(2) concentration is, the higher the reactivity of the mixture towards CH(4) oxidation-probably due to a higher production of H(2) reactive radicals (OH).

  6. Demonstration of the First 4H-SiC EUV Detector with Large Detection Area

    NASA Technical Reports Server (NTRS)

    Xin, Xiaobin; Yan, Feng; Koeth, Timothy W.; Hu, Jun; Zhao, Jian H.

    2005-01-01

    Ultraviolet (UV) and Extreme Ultraviolet (EUV) detectors are very attractive in astronomy, photolithography and biochemical applications. For EUV applications, most of the semiconductor detectors based on PN or PIN structures suffer from the very short penetration depth. Most of the carries are absorbed at the surface and recombined there due to the high surface recombination before reach the depletion region, resulting very low quantum efficiency. On the other hand, for Schottky structures, the active region starts from the surface and carriers generated from the surface can be efficiently collected. 4H-Sic has a bandgap of 3.26eV and is immune to visible light background noise. Also, 4H-Sic detectors usually have very good radiation hardness and very low noise, which is very important for space applications where the signal is very weak. The E W photodiodes presented in this paper are based on Schottky structures. Platinum (Pt) and Nickel (Ni) are selected as the Schottky contact metals, which have the highest electron work functions (5.65eV and 5.15eV, respectively) among all the known metals on 4H-Sic.

  7. Laboratory detection of the C3N an C4H free radicals

    NASA Technical Reports Server (NTRS)

    Gottlieb, C. A.; Gottlieb, E. W.; Thaddeus, P.; Kawamura, H.

    1983-01-01

    The millimeter-wave spectra of the linear carbon chain free radicals C3N and C4H, first identified in IRC + 10216 and hitherto observed only in a few astronomical sources, have been detected with a Zeeman-modulated spectrometer in laboratory glow discharges through low pressure flowing mixtures of N2 + HC3N and He + HCCH, respectively. Four successive rotational transitions between 168 and 198 GHz have been measured for C3N, and five rotational transitions between 143 and 200 GHz for C4H; each is a well-resolved spin doublet owing to the unpaired electron present in both species. Precise values for the rotational, centrifugal distortion, and spin doubling constants have been obtained, which, with hyperfine constants derived from observations of the lower rotational transitions in the astronomical source TMC 1, allow all the rotational transitions of C3N and C4H at frequencies less than 300 GHz to be calculated to an absolute accuracy exceeding 1 ppm.

  8. A remarkable activity of human leukotriene A4 hydrolase (LTA4H) toward unnatural amino acids.

    PubMed

    Byzia, Anna; Haeggström, Jesper Z; Salvesen, Guy S; Drag, Marcin

    2014-05-01

    Leukotriene A4 hydrolase (LTA4H--EC 3.3.2.6) is a bifunctional zinc metalloenzyme, which processes LTA4 through an epoxide hydrolase activity and is also able to trim one amino acid at a time from N-terminal peptidic substrates via its aminopeptidase activity. In this report, we have utilized a library of 130 individual proteinogenic and unnatural amino acid fluorogenic substrates to determine the aminopeptidase specificity of this enzyme. We have found that the best proteinogenic amino acid recognized by LTA4H is arginine. However, we have also observed several unnatural amino acids, which were significantly better in terms of cleavage rate (k cat/K m values). Among them, the benzyl ester of aspartic acid exhibited a k cat/K m value that was more than two orders of magnitude higher (1.75 × 10(5) M(-1) s(-1)) as compared to L-Arg (1.5 × 10(3) M(-1) s(-1)). This information can be used for design of potent inhibitors of this enzyme, but may also suggest yet undiscovered functions or specificities of LTA4H.

  9. Extended charge accumulation in ruthenium-4H-imidazole-based black absorbers: a theoretical design concept.

    PubMed

    Kupfer, Stephan

    2016-05-11

    A theoretical-guided design concept aiming to achieve highly efficient unidirectional charge transfer and multi-charge separation upon successive photoexcitation for light-harvesting dyes in the scope of supramolecular photocatalysts is presented. Four 4H-imidazole-ruthenium(ii) complexes incorporating a biimidazole-based electron-donating ligand sphere have been designed based on the well-known 4H-imidazole-ruthenium(ii) polypyridyl dyes. The quantum chemical evaluation, performed at the density functional and time-dependent density functional level of theory, revealed extraordinary unidirectional charge transfer bands from the near-infrared to the ultraviolet region of the absorption spectrum upon multi-photoexcitation. Spectro-electrochemical simulations modeling photoexcited intermediates determined the outstanding multi-electron storage capacity for this novel class of black dyes. These remarkable photochemical and photophysical properties are found to be preserved upon site-specific protonation rendering 4H-imidazole-ruthenium(ii) biimidazole dyes ideal for light-harvesting applications in the field of solar energy conversion. PMID:27121270

  10. Multiple shell fusion targets

    DOEpatents

    Lindl, J.D.; Bangerter, R.O.

    1975-10-31

    Multiple shell fusion targets for use with electron beam and ion beam implosion systems are described. The multiple shell targets are of the low-power type and use a separate relatively low Z, low density ablator at large radius for the outer shell, which reduces the focusing and power requirements of the implosion system while maintaining reasonable aspect ratios. The targets use a high Z, high density pusher shell placed at a much smaller radius in order to obtain an aspect ratio small enough to protect against fluid instability. Velocity multiplication between these shells further lowers the power requirements. Careful tuning of the power profile and intershell density results in a low entropy implosion which allows breakeven at low powers. For example, with ion beams as a power source, breakeven at 10-20 Terrawatts with 10 MeV alpha particles for imploding a multiple shell target can be accomplished.

  11. Interfacial atomic site characterization by photoelectron diffraction for 4H-AlN/4H-SiC(11\\bar{2}0) heterojunction

    NASA Astrophysics Data System (ADS)

    Maejima, Naoyuki; Horita, Masahiro; Matsui, Hirosuke; Matsushita, Tomohiro; Daimon, Hiroshi; Matsui, Fumihiko

    2016-08-01

    The interfacial atomic structure of an AlN thin film on a nonpolar 4H-SiC(11\\bar{2}0) substrate grown by atomic Al and N plasma deposition was studied by photoelectron diffraction and spectroscopy. The epitaxial growth of the thin film was confirmed by the comparison of element-specific photoelectron intensity angular distributions (PIADs). Depth profiles were analyzed by angle-resolved constant-final-state-mode X-ray photoelectron spectroscopy (AR-XPS). No polar angular dependence was observed in Al 2p spectra, while an additional intermixing component was found in interface-sensitive N 1s spectra. The site-specific N 1s PIADs for the AlN film and an intermixing component were derived from two N 1s PIADs with different binding energies. We attributed the intermixing component to SiN interfacial layer sites. In order to prevent SiN growth at the interface, we deposited Al on the SiC(11\\bar{2}0) substrate prior to the AlN growth. A significant reduction in the amount of intermixing components at the AlN/SiC interface was confirmed by AR-XPS.

  12. Imperfection Insensitive Thin Shells

    NASA Astrophysics Data System (ADS)

    Ning, Xin

    The buckling of axially compressed cylindrical shells and externally pressurized spherical shells is extremely sensitive to even very small geometric imperfections. In practice this issue is addressed by either using overly conservative knockdown factors, while keeping perfect axial or spherical symmetry, or adding closely and equally spaced stiffeners on shell surface. The influence of imperfection-sensitivity is mitigated, but the shells designed from these approaches are either too heavy or very expensive and are still sensitive to imperfections. Despite their drawbacks, these approaches have been used for more than half a century. This thesis proposes a novel method to design imperfection-insensitive cylindrical shells subject to axial compression. Instead of following the classical paths, focused on axially symmetric or high-order rotationally symmetric cross-sections, the method in this thesis adopts optimal symmetry-breaking wavy cross-sections (wavy shells). The avoidance of imperfection sensitivity is achieved by searching with an evolutionary algorithm for smooth cross-sectional shapes that maximize the minimum among the buckling loads of geometrically perfect and imperfect wavy shells. It is found that the shells designed through this approach can achieve higher critical stresses and knockdown factors than any previously known monocoque cylindrical shells. It is also found that these shells have superior mass efficiency to almost all previously reported stiffened shells. Experimental studies on a design of composite wavy shell obtained through the proposed method are presented in this thesis. A method of making composite wavy shells and a photogrametry technique of measuring full-field geometric imperfections have been developed. Numerical predictions based on the measured geometric imperfections match remarkably well with the experiments. Experimental results confirm that the wavy shells are not sensitive to imperfections and can carry axial compression

  13. Geometry-Lithology-Origin: Solving the mystery of the Late Miocene mounded features below Lake Balaton

    NASA Astrophysics Data System (ADS)

    Visnovitz, Ferenc; Horváth, Ferenc; Surányi, Gergely

    2014-05-01

    The Department of Geophysics and Space Sciences of Eötvös University has carried out single- and multichannel water seismic surveys at the Lake Balaton since 1993. The dense grid of 2D profiles offers a high resolution image of the Late Miocene sedimentary strata (Tihany, Somló and Szák Formations) up to a thickness of 200 meters below the lake. These strata can be divided into smaller sedimentary units by numerous parasequence boundaries (Sztanó&Magyar, 2007). In one of these parasequence interesting, high amplitude mounded features have been observed that follow a seismic horizon over large area. It means that these features indicate a Late Miocene regional event. In terms of their shape these mounds are few tens of meters wide, several tens to a hundreds of meters long and few meters high. Their geometry and inner structure were mapped from 2D segments that were used for 3D reconstructions. The shape and stratigraphic position of these features have inspired Sacchi and Horvath (1999) to interpret them as the subsurface equivalent of the fresh-water siliceous-limestone mounds exposed on the Tihany Peninsula. They held these mounds as an evidence of dryland conditions in the time period of the formation of a Late Miocene erosional surface (PAN-2) that they regarded as a 3rd order sequence boundary. In addition to this so called "travertine" concept another explanation was also formulated as the mounds are the product of sedimentary failures e.g. slumps or water escape. To solve the problem an offshore drilling with a total depth of 19 meters was accomplished in October 2013 to sample one of these mounds and determine their origin. The well has not crossed any travertine body, instead alternating layers of clay-silt and very fine sand - without any convincing sign of fluid escape structures - were found in the core (typical lithology of the Tihany Formation). 3D structural analysis of the mounds revealed spherical organization composing bodies that are

  14. Genesis and fluid source in Arabia crater mounds: mapping, fractal analysis, and impact simulations

    NASA Astrophysics Data System (ADS)

    Pozzobon, R.; Mazzarini, F.; Rossi, A.; Lucchetti, A.; Pondrelli, M.; Marinangeli, L.; Martellato, E.; Cremonese, G.; Massironi, M.

    2013-12-01

    Arabia Terra is dominated by heavily cratered terrains, and some peculiar landforms can be found mostly in craters interior. With high-resolution images from HiRISE (25 cm/px) and CTX (6 m/px) cameras pitted cones, mounds and knobs can be easily recognized. Those mounds are interpreted to have worked as pathways for subsurface fluid. It is commonly hypothesized that Arabia Terra is an area of past fluid activity, being crater central bulges a place of sulfate precipitation. In this work we investigate the presence, origin and timing of their formation as well as the the depth of the mounds fluid source. The spatial distribution of monogenic eruptive structures within volcanic areas on Earth has been linked to fracture systems that allowed an efficient hydraulic connection between surface and crustal or subcrustal magma reservoirs. Self-similarity in vent distribution is described by a power law distribution with fractal exponent D and defined over a range of lengths comprised between a lower limit (lower cutoff, Lco) and an upper limit (upper cutoff, Uco). On Earth, volcanic vents as well as mud volcanoes have shown that the Uco of their fractal distribution scales with the depth of pressurized fluid reservoirs. The same approach has been this applied to mounds mapped at Firsoff and Crommelin craters. 431 mounds were mapped on Firsoff Crater's floor, and 160 on Crommelin Crater's floor. The reslulting Uco for both craters are similar giving a source depth of 2.3 ×0.3 km from Firsoff Crater's ground floor and 2.6 ×0.5 km from Crommelin's floor. Hence it is possible to hypothesize a common regional-scale pressurized fluid level at 2.5 km of depth from craters floor. Morphogic and stratigraphical analyses of the high-resolution imagery and topography of those mounds allowed us to discern from actual mud volcano candidates and stratigraphic erosional remnants. We also studied the craters formation by simulating the impact with the hydrocode. We used iSALE shock code

  15. Sources of Sulfate Found in Mounds and Lakes at the Lewis Cliffs Ice Tongue, Transantarctic

    NASA Technical Reports Server (NTRS)

    Socki, Richard; Sun, Tao; Harvey, Ralph P.; Bish, David L.; Tonui, Eric; Bao, Huiming; Niles, Paul B.

    2012-01-01

    Massive but highly localized Na-sulfate mounds (mirabilite, Na2SO4.10H2O) have been found at the terminal moraine of the Lewis Cliffs Ice Tongue (LCIT), Antarctica. (Sigma)34S and (Sigma)18O values of LCIT mirabilite range from +48.8 to +49.3% (CDT), and -16.6 to -17.1% (V-SMOW), respectively, while (Delta)17O average -0.37% (V-SMOW). LCIT mirabilite mounds are isotopically different from other mirabilite mounds found in coastal regions of Antarctica, which have isotope values close to seawater compositions. (Sigma)18O and (Delta)17O values suggest the incorporation of isotopically light glacial water. Data point to initial sulfate formation in an anoxic water body, either as a stratified anoxic deep lake on the surface, a sub-glacial water reservoir, or a sub-glacial lake. Several surface lakes of varying size are also present within this region of the LCIT, and in some cases are adjacent to the mirabilite mounds. O and D isotope compositions of surface lakes confirm they are derived from a mixture of glacial ice and snow that underwent moderate evaporation. (Sigma)18O and (Sigma)D (V-SMOW) values of snow, ice, and lake water range from -64.2 to -29.7%, and -456.0 to -231.7%, respectively. However, the isotope chemistry of these surface lakes is extremely different from the mounds. Dissolved SO4-2 (Sigma)34S and (Sigma)18O values range from +12.0 to +20.0% and -12.8 to -22.2% (the most negative (Sigma)18O of terrestrial sulfate ever reported), respectively, with sulfate (Delta)17O ranging from +0.93 to 2.24%. Ion chromatography data show that lake water is fresh to brackish in origin, with TDS less than 1500 ppm, and sulfate concentration less than 431 ppm. Isotope and chemical data suggest that these lakes are unlikely the source of the mirabilite mounds. We suggest that lake water sulfate is potentially composed of a mixture of atmospheric sulfate and minor components of sulfate of weathering origin, much like the sulfate in the polar plateau soils of the Mc

  16. Methane fluxes from the mound-building termite species of North Australian savannas

    NASA Astrophysics Data System (ADS)

    Jamali, H.; Livesely, S. J.; Arndt, S. K.; Dawes-Gromadzki, T.; Cook, G. D.; Hutley, L.

    2009-04-01

    Termites are estimated to contribute 3-19% to the global methane emissions. These estimates have large uncertainties because of the limited number of field-based studies and species studied, as well as issues of diel and seasonal variation. We measured methane fluxes from four common mound-building termite species (Microcerotermes nervosus, n=26; M. serratus, n=4; Tumulitermes pastinator, n=5; and Amitermes darwini, n=4) in tropical savannas near Darwin in the Northern Territory, Australia. Methane fluxes from replicated termite mounds were measured in the field using manual chambers with fluxes reported on a mound volume basis. Methane flux was measured in both wet and dry seasons and diel variation was investigated by measuring methane flux every 4 hours over a 24 hour period. Mound temperature was measured concurrently with flux to examine this relationship. In addition, five M. nervosus mounds removed from the field and incubated under controlled temperature conditions over a 24 hour period to remove the effect of varying temperature. During the observation campaigns, mean monthly minimum and maximum temperatures for February (wet season) were 24.7 and 30.8°C, respectively, and were 20.1 to 31.4 °C in June (dry season). Annual rainfall in 2008 for Darwin was 1970.1 mm, with a maximum of 670 mm falling in February and no rain in May and June. Methane fluxes were greatest in the wet season for all species, ranging from 265.1±101.1 (T. pastinator) to 2256.6±757.1 (M. serratus) µg CH4-C/m3/h. In the dry season, methane fluxes were at their lowest, ranging from 10.0±5.5 (T. pastinator) to 338.0±165.9 (M. serratus) µg CH4-C/m3/h. On a diel basis, methane fluxes were smallest at the coolest time of the day (~0700 hrs) and greatest at the warmest (~1400 hrs) for all species, and for both wet and dry seasons. Typical diel variation in flux from M. serratus dominated mounds ranged from 902.6±261.9 to 1392.1±408.1 µg CH4-C/m3/h in wet season and 99.6±57.4 to

  17. Corrosion of copper in Mound's single-pass potable water systems

    SciTech Connect

    Schleitweiler, P.M.; Miller, P.S.

    1990-12-07

    An increase in the number of copper plumbing failures at Mound prompted a thorough analysis of the failed components. Most of the components were elbow joints. All of these parts exhibited the same type of accelerated deterioration. The failed parts were analyzed optically and by scanning electron microscopy. Water chemistry, solder, and soldering fluxes were evaluated to determine their possible roles in the accelerated attack. Cross-sectioning of the elbow joints revealed residual soldering flux and cutting burrs on the inside of the elbows. Water analysis showed Mound's water was rated as corrosive. Recommendations for improved workmanship and design are presented. Testing of potable water at a regular basis was also recommended. 8 refs., 10 figs., 3 tabs.

  18. Composting of cow dung and crop residues using termite mounds as bulking agent.

    PubMed

    Karak, Tanmoy; Sonar, Indira; Paul, Ranjit K; Das, Sampa; Boruah, R K; Dutta, Amrit K; Das, Dilip K

    2014-10-01

    The present study reports the suitability of termite mounds as a bulking agent for composting with crop residues and cow dung in pit method. Use of 50 kg termite mound with the crop residues (stover of ground nut: 361.65 kg; soybean: 354.59 kg; potato: 357.67 kg and mustard: 373.19 kg) and cow dung (84.90 kg) formed a good quality compost within 70 days of composting having nitrogen, phosphorus and potassium as 20.19, 3.78 and 32.77 g kg(-1) respectively with a bulk density of 0.85 g cm(-3). Other physico-chemical and germination parameters of the compost were within Indian standard, which had been confirmed by the application of multivariate analysis of variance and multivariate contrast analysis. Principal component analysis was applied in order to gain insight into the characteristic variables. Four composting treatments formed two different groups when hierarchical cluster analysis was applied.

  19. Island-dynamics model for mound formation: effect of a step-edge barrier.

    PubMed

    Papac, Joe; Margetis, Dionisios; Gibou, Frederic; Ratsch, Christian

    2014-08-01

    We formulate and implement a generalized island-dynamics model of epitaxial growth based on the level-set technique to include the effect of an additional energy barrier for the attachment and detachment of atoms at step edges. For this purpose, we invoke a mixed, Robin-type, boundary condition for the flux of adsorbed atoms (adatoms) at each step edge. In addition, we provide an analytic expression for the requisite equilibrium adatom concentration at the island boundary. The only inputs are atomistic kinetic rates. We present a numerical scheme for solving the adatom diffusion equation with such a mixed boundary condition. Our simulation results demonstrate that mounds form when the step-edge barrier is included, and that these mounds steepen as the step-edge barrier increases. PMID:25215739

  20. Association among active seafloor deformation, mound formation, and gas hydrate growth and accumulation within the seafloor of the Santa Monica Basin, offshore California

    USGS Publications Warehouse

    Paull, C.K.; Normark, W.R.; Ussler, W.; Caress, D.W.; Keaten, R.

    2008-01-01

    Seafloor blister-like mounds, methane migration and gas hydrate formation were investigated through detailed seafloor surveys in Santa Monica Basin, offshore of Los Angeles, California. Two distinct deep-water (??? 800??m water depth) topographic mounds were surveyed using an autonomous underwater vehicle (carrying a multibeam sonar and a chirp sub-bottom profiler) and one of these was explored with the remotely operated vehicle Tiburon. The mounds are > 10??m high and > 100??m wide dome-shaped bathymetric features. These mounds protrude from crests of broad anticlines (~ 20??m high and 1 to 3??km long) formed within latest Quaternary-aged seafloor sediment associated with compression between lateral offsets in regional faults. No allochthonous sediments were observed on the mounds, except slumped material off the steep slopes of the mounds. Continuous streams of methane gas bubbles emanate from the crest of the northeastern mound, and extensive methane-derived authigenic carbonate pavements and chemosynthetic communities mantle the mound surface. The large local vertical displacements needed to produce these mounds suggests a corresponding net mass accumulation has occurred within the immediate subsurface. Formation and accumulation of pure gas hydrate lenses in the subsurface is proposed as a mechanism to blister the seafloor and form these mounds. ?? 2008 Elsevier B.V. All rights reserved.

  1. Organic matter quality and supply to deep-water coral/mound systems of the NW European Continental Margin

    NASA Astrophysics Data System (ADS)

    Kiriakoulakis, K.; Freiwald, A.; Fisher, E.; Wolff, G. A.

    2007-02-01

    Comparison of five deep-water coral (DWC)/mound ecosystems along the European Continental Margin shows that suspended particulate organic matter (sPOM), a potential food source, is lipid rich and of high quality. However, there are differences between the sites. The Darwin and Pelagia Mounds (N. Rockall Trough and N. Porcupine Bank, respectively) have higher proportions of labile particulate lipids (including high proportions of polyunsaturated fatty acids) in the benthic boundary layer than Logachev, Hovland and Belgica Mounds (Rockall Bank, S. Porcupine Bank and Porcupine Seabight, respectively). The high quality sPOM could be transported downslope from the euphotic zone. There is some evidence for inter-annual variability at some sites (e.g. Hovland and Logachev Mounds) as large differences in suspended lipid and particulate organic carbon concentrations were observed over the sampling period. Elevated total organic carbon contents of sediments at mound sites, relative to control sites in some cases (particularly Darwin Mounds), probably reflect local hydrodynamic control and the trapping of sPOM by the DWC. Fresh POM can be relatively rapidly transferred to significant depth (up to 8 cm) through bioturbation that is evident at all sites. There is no clear evidence of present day hydrocarbon seepage at any of the sites.

  2. Do epigeal termite mounds increase the diversity of plant habitats in a tropical rain forest in peninsular Malaysia?

    PubMed

    Beaudrot, Lydia; Du, Yanjun; Rahman Kassim, Abdul; Rejmánek, Marcel; Harrison, Rhett D

    2011-01-01

    The extent to which environmental heterogeneity can account for tree species coexistence in diverse ecosystems, such as tropical rainforests, is hotly debated, although the importance of spatial variability in contributing to species co-existence is well recognized. Termites contribute to the micro-topographical and nutrient spatial heterogeneity of tropical forests. We therefore investigated whether epigeal termite mounds could contribute to the coexistence of plant species within a 50 ha plot at Pasoh Forest Reserve, Malaysia. Overall, stem density was significantly higher on mounds than in their immediate surroundings, but tree species diversity was significantly lower. Canonical correspondence analysis showed that location on or off mounds significantly influenced species distribution when stems were characterized by basal area. Like studies of termite mounds in other ecosystems, our results suggest that epigeal termite mounds provide a specific microhabitat for the enhanced growth and survival of certain species in these species-rich tropical forests. However, the extent to which epigeal termite mounds facilitate species coexistence warrants further investigation.

  3. Dickinson field lodgepole reservoir: Significance of this Waulsortian-type mound to exploration in the Williston Basin

    SciTech Connect

    Johnson, M.S.

    1995-07-01

    Conoco`s No. 74 Dickinson State well, a deep test in Dickinson Field, Stark County, North Dakota, was completed in early 1993 capable of producing over 2,000 BOPD. It represents the first commercial oil production from the Lower Mississippian Lodgepole Formation in the U.S. portion of the Williston Basin. Three additional oil producers have now been completed and this Lodgepole discovery is fully developed. The producing reservoir, at depths of 9,700 to 10,000 ft, is a Waulsortian-type mound approximately 300 ft thick with a characteristic faunal assemblage of bryozoans and crinoids. The mound has an areal extent of slightly more than 1 square mile. Similar Waulsortian-type mounds have been recognized in rocks of Paleozoic age around the world, but have only been reported in the Williston Basin during the past decade. Such mounds are shallow to deep water deposits, tend to develop over structurally or topographically-positive areas, and may form by algal or by current action in conjunction with baffling action caused by bryozoans. The prolific nature of the Conoco discovery, plus several more-recent excellent mound discoveries in this same area, have caused renewed drilling and leasing activity. These events have also encouraged a review of existing seismic data, the shooting of new 3-D seismic programs and re-analysis of wells previously drilled through the Lodgepole Formation for evidence of similar mounds elsewhere in the basin.

  4. Decadal-scale variations in geomagnetic field intensity from ancient Cypriot slag mounds

    NASA Astrophysics Data System (ADS)

    Shaar, Ron; Tauxe, Lisa; Ben-Yosef, Erez; Kassianidou, Vasiliki; Lorentzen, Brita; Feinberg, Joshua M.; Levy, Thomas E.

    2015-01-01

    models based on direct observations since the 1830s show that the averaged relative change in field intensity on Earth's surface over the past 170 years is less than 4.8% per decade. It is unknown if these rates represent the typical behavior of secular variations due to insufficient temporal resolution of archaeomagnetic records from earlier periods. To address this question, we investigate two ancient slag mounds in Cyprus—Skouriotissa Vouppes (SU1, fourth to fifth centuries CE, 21 m in height), and Mitsero Kokkinoyia (MK1, seventh to fifth centuries BCE, 8 m in height). The mounds are multilayered sequences of slag and charcoals that accumulated near ancient copper production sites. We modeled the age-height relation of the mounds using radiocarbon dates, and estimated paleointensities using Thellier-type IZZI experiments with additional anisotropy, cooling rate, and nonlinear TRM assessments. To screen out ambiguous paleointensity interpretations, we applied strict selection criteria at the specimen/sample levels. To ensure objectivity, consistency, and robust error estimation, we employed an automatic interpretation technique and put the data available in the MagIC database. The analyses yielded two independent subcentury-scale paleointensity time series. The MK1 data indicate relatively stable field at the time the mound accumulated. In contrast, the SU1 data demonstrate changes that are comparable in magnitude to the fastest changes inferred from geomagnetic models. We suggest that fast changes observed in the published archaeomagnetic data from the Levant are driven by two longitudinally paired regions, the Middle East and South Africa, that show unusual activity in geomagnetic models.

  5. Deciduous enamel defects in prehistoric Americans from Dickson Mounds: prenatal and postnatal stress.

    PubMed

    Blakey, M L; Armelagos, G J

    1985-04-01

    The month of onset, duration, and incidence of dental enamel hypoplasia and hypocalcification was determined in sub-adults from the Dickson Mounds (Illinois) skeletal series (A.D. 950-1300). The onset of enamel defects occurred predominantly during the intrauterine period, suggesting maternal stress. There are marked differences in survivorship and the duration of enamel disruption in those affected prenatally and postnatally. The relationship between these data and studies of adult dentition is examined.

  6. Brief communication: Conjoined twins at angel mounds? an ancient DNA perspective.

    PubMed

    Marshall, Charla; Tench, Patricia A; Cook, Della Collins; Kaestle, Frederika A

    2011-09-01

    Conjoined twins are born when a single fertilized egg partially splits into two fetuses. A hypothetical case of infant conjoined twins from Angel Mounds, a Middle Mississippian site (A.D. 1050-1400) on the Ohio River near Evansville, Indiana, was discovered in 1941. Morphological analysis does not rule out the field interpretation of this double burial as twins. Ancient mitochondrial DNA recovered from both infants demonstrates that they were not maternal relatives, and hence that they cannot have been conjoined twins.

  7. Chemistry and mineralogy of samples from the strategic petroleum reserve Bryan Mound site

    SciTech Connect

    Bild, R. W.

    1980-08-01

    The goal of the Strategic Petroleum Reserve (SPR) program is to protect the United States from a temporary cutoff of imported crude oil by stockpiling a reserve of oil in caverns in Gulf Coast salt domes. Some suitable caverns already exist as a result of solution mining activities by commercial mining companies. Most of the caverns for the program, however, will be solution mined specifically for the SPR program. The tasks assigned to Sandia National Laboratories include conducting a geotechnical program and providing interim technical support for the leaching of the first five caverns in the Bryan Mound, Texas, salt dome. This report describes chemical, mineralogical and petrological work done at Sandia as of May 1, 1980 in support of Bryan Mound activities. Samples of Bryan Mound salt cores, sidewall samples and drill cuttings have been subjected to chemical, mineralogical and petrographic analysis. Halite (NaCl) was the major mineral in all samples with anhydrite (CaSO/sub 4/) a common accessory. Minor or trace sylvite (KCl) and quartz (SiO/sub 2/) were detected in some sidewall samples. Other minor minerals found in drill cuttings included quartz; mixed carbonates of Fe, Ca and Mg; and several iron oxides. Possibly the carbonates are reaction products with the basic drilling mud or possibly pieces of caprock which contaminated the cuttings. The iron oxides were probably produced by corrosion of the drill stem or bit. Densities of several core samples were determined and insoluble residue was counted for radioactivity.

  8. Pre-operational safety appraisal Tritiated Scrap Recovery Facility, Mound facility

    SciTech Connect

    Dauby, J.J.; Flanagan, T.M.; Metcalf, L.W.; Rhinehammer, T.B.

    1996-07-01

    The purpose of this report is to identify, assess, and document the hazards which are associated with the proposed operation of the Tritiated Scrap Recovery Facility at Mound Facility. A Pre-operational Safety Appraisal is a requirement as stated in Department of Energy Order 5481.1, Safety Analysis and Review System. The operations to be conducted in the new Tritiated Scrap Waste Recovery Facility are not new, but a continuation of a prime mission of Mound`s i.e. recovery of tritium from waste produced throughout the DOE complex. The new facility is a replacement of an existing process started in the early 1960`s and incorporates numerous design changes to enhance personnel and environmental safety. This report also documents the safety of a one time operation involving the recovery of tritium from material obtained by the Department of Energy from the State of Arizona. This project will involve the processing of 240,000 curies of tritium contained in glass ampoules that were to be used in items such as luminous dial watches. These were manufactured by the now defunct American Atomics Corporation, Tucson, Arizona.

  9. Mineralogy, chemical composition and structure of the MIR Mound, TAG Hydrothermal Field

    NASA Astrophysics Data System (ADS)

    Stepanova, T. V.; Krasnov, S. G.; Cherkashev, G. A.

    The study of samples collected from the surface of the MIR mound (TAG Hydrothermal Field) by video-controlled hydraulic grab allowed identification of a number of mineralogical types. These include pyrite-chalcopyrite (Py-Cp), bornite-chalcopyrite-opaline (Bn-Cp-Op) and sphalerite-opaline (Sp-Op) sulfide chimneys, massive sulfides composed of pyrite (Py), chalcopyrite-pyrite (Cp-Py), marcasite-pyrite-opaline (Mc-Py-Op), sphalerite-pyrite-opaline (Sp-Py-Op) and sphalerite-chalcopyrite-pyrite-opaline (Sp-Cp-Py-Op), as well as siliceous and Fe-Mn oxide hydrothermal deposits. Most of the minor elements (Ag, Au, Cd, Ga, Hg, Sb and Pb) are associated with Zn-rich massive sulfides, Co Bi, Pb, and As with Ferich ones, while Cu-rich sulfides are depleted of trace metals. Cu-enriched assemblages are concentrated in the northern part, Zn-enriched in the center, and siliceous rocks in the south of the MIR mound. According to paragenetic relations, the development of the mound started with the formation of quartz (originally opaline) rocks and dendritic assemblages of melnikovite-pyrite, followed by deposition of chalcopyrite and recrystallization of primary pyrite, subsequent generation of sphalerite-rich assemblages and final deposition of opaline rocks. The late renewal of hydrothermal activity led to local formation of Cu-rich chimneys enriched in Au, Ag, Hg and Pb probably due to their remobilization from inner parts of the deposit.

  10. The Nest Growth of the Neotropical Mound-Building Termite, Cornitermes cumulans: A Micromorphological Analysis

    PubMed Central

    Cosarinsky, Marcela I.

    2011-01-01

    The nests of Cornitermes cumulans K. (Isoptera: Termitidae), a very common termite in South American grasslands, display notable morphological transformations during the development of the colony. Young colonies inhabit small subterranean nests that develop into large, conspicuous, epigean mounds, inhabited by very populous colonies. Those macromorphological transformations are accompanied by micromorphological changes occurring gradually in the nest walls. The micromorphological changes during nest development described in the present study expand on previous macromorphological descriptions by explaining the re-organization of the soil components during nest growth. In subterranean nests, walls are composed of piles of lensshaped aggregates of soil material, each one surrounded by a thin organic coating. As the nest grows, mound walls are constructed by disassembling this first lenticular structure and rearranging the materials in a new fabric, where sand grains are loosely distributed among soil microaggregates of organic matter and clay. This is also a temporary construction, because the walls of large nests are composed of a porous mass of sands densely cemented with organic matter and clay in the mound, and a compact mass of the same components in the floor. PMID:22224433

  11. Ultra-High Voltage 4H-SiC Bi-Directional Insulated Gate Bipolar Transistors

    NASA Astrophysics Data System (ADS)

    Chowdhury, Sauvik

    4H- Silicon Carbide (4H-SiC) is an attractive material for power semiconductor devices due to its large bandgap, high critical electric field and high thermal conductivity compared to Silicon (Si). For ultra-high voltage applications (BV > 10 kV), 4H-SiC Insulated Gate Bipolar Transistors (IGBTs) are favored over unipolar transistors due to lower conduction losses. With improvements in SiC materials and processing technology, promising results have been demonstrated in the area of conventional unidirectional 4H-SiC IGBTs, with breakdown voltage ratings up to 27 kV. This research presents the experimental demonstration of the world's first high voltage bi-directional power transistors in 4H-SiC. Traditionally, four (two IGBTs and two diodes) or two (two reverse blocking IGBTs) semiconductor devices are necessary to yield a bidirectional switch. With a monolithically integrated bidirectional switch as presented here, the number of semiconductor devices is reduced to only one, which results in increased reliability and reduced cost of the overall system. Additionally, by using the unique dual gate operation of BD-IGBTs, switching losses can be reduced to a small fraction of that in conventional IGBTs, resulting in increased efficiency. First, the performance limits of SiC IGBTs are calculated by using analytical methods. The performance benefits of SiC IGBTs over SiC unipolar devices and Si IGBTs are quantified. Numerical simulations are used to optimize the unit cell and edge termination structures for a 15 kV SiC BD-IGBT. The effect of different device parameters on BD-IGBT static and switching performance are quantified. Second, the process technology necessary for the fabrication of high voltage SiC BD-IGBTs is optimized. The effect of different process steps on parameters such as breakdown voltage, carrier lifetime, gate oxide reliability, SiO2-SiC interface charge density is quantified. A carrier lifetime enhancement process has been optimized for lightly doped

  12. Iridescence color of shells

    NASA Astrophysics Data System (ADS)

    Liu, Yan

    2002-06-01

    Some shells from both salt water and fresh water show the phenomenon of iridescence color. Pearls and mother-of-pearls also display this phenomenon. In the past, the cause of the iridescence color was attributed to interference. A scanning electron microscope (SEM) was used to study the surface structure of the shell of the mollusk Pinctada Margaritifera. There is a groove structure of reflection grating on the surface area in where the iridescence color appears. An optic experiment with a laser obtained a diffraction pattern produced by the reflection grating structure of the shell. The study led to a conclusion that the iridescence color of the shell is caused by diffraction. A SEM image of the shells of an abalone Haliotis Rufescens (red abalone) showed a statistically regularly arranged tile structure that serves as a two-dimensional grating. This grating structure causes the iridescence color of the shell of red abalone. The dominant color of the iridescence of shells is caused by the uneven grating efficiency in the visible wavelength range when a shell functions as a reflection grating. The wavelength of the dominant color should be at or near the wavelength of the maximum efficiency of the grating.

  13. Static cylindrical matter shells

    NASA Astrophysics Data System (ADS)

    Arık, Metin; Delice, Özgür

    2005-08-01

    Static cylindrical shells composed of massive particles arising from matching of two different Levi-Civita space-times are studied for the shell satisfying either an isotropic or an anisotropic equation of state. We find that these solutions satisfy the energy conditions for certain ranges of the parameters.

  14. Atomistic Simulations of Epitaxial Recrystallization in 4H-SiC along the [0001] Direction

    SciTech Connect

    Gao, Fei; Zhang, Yanwen; Devanathan, Ram; Posselt, Matthias; Weber, William J.

    2007-02-16

    Molecular dynamics (MD) methods have been employed to study the epitaxail recrystallization and amorphous-to-crystalline (a-c) transition in 4H-SiC, with simulation times of up to a few hundred ns and at temperatures of 1500 and 2000 K. Three nano-sized amorphous layers with the normal of a-c interfaces along the [-12-10 ], [-1010] and [0001] directions, respectively, were created within a crystalline cell to investigate the anisotropies of recrystallization processes. The recovery of bond defects at the interfaces is an important process driving the initial epitaxial recrystallization of the amorphous layers. The amorphous layers with the a-c interface normal along the [-12-10] direction can be completely recrystallized at the temperatures of 1500 and 2000 K, and along the [0001] direction at 2000 K. However, the recrystallized region is defected with dislocations and stacking faults. The temperatures required for complete recrystallization are in good agreement with those observed in experiments. On the other hand, the recrystallization processes for the a-c interface normal along [-1010] direction are hindered by the nucleation of polycrystalline phases. These secondary ordered phases have been identified as 4H- and 3C-SiC with different crystallographic orientations to the original 4H-SiC. The bond mismatches at the interfaces between different microcrystals result in the formation of a number of stacking faults. The temperature is an important parameter to control the nucleation of the secondary ordered phase, whereas the size of amorphous region has a significant effect on their growth. These results are in good agreement with the previous experimental observations.

  15. High responsivity 4H-SiC based metal-semiconductor-metal ultraviolet photodetectors

    NASA Astrophysics Data System (ADS)

    Yang, Weifeng; Zhang, Feng; Liu, Zhuguang; Lü, Ying; Wu, Zhengyun

    2008-11-01

    4H-SiC based metal-semiconductor-metal (MSM) photodetectors with diverse spacing were designed, fabricated, and characterized, in which nickel Schottky contacts were needed. Current-voltage and spectral responsivity measurements were carried out at room temperature. The fabricated 4 μm-spacing device showed a very low dark current (0.25 pA at 5 V bias voltage), a typical responsivity of 0.103 A/W at 20 V, and a peak response wavelength at 290 nm. The fabricated devices held a high DUV to visible rejection ratio of >103.

  16. Transient collector modulation of 4H-SiC BJTs during switch-on process

    NASA Astrophysics Data System (ADS)

    Yuferev, Valentin S.; Levinshtein, Michael E.; Ivanov, Pavel A.; Zhang, Jon Q.; Palmour, John W.

    2016-09-01

    Main physical features of the collector resistance modulation processes have been studied via a one-dimensional simulation for n+-p-n0-n+ 4H-SiC bipolar junction transistor. The motion dynamics of minority carriers (holes) across the n0 collector layer during the switch-on process is traced. It is demonstrated that the effective modulation of the collector resistance is only possible in the case of a rather fast transistor switch-on. A necessary condition for the fast switch-on is the large amplitude and short leading edge of the base current pulse.

  17. Hydrogen Gas Sensors Fabricated on Atomically Flat 4H-SiC Webbed Cantilevers

    NASA Technical Reports Server (NTRS)

    Neudeck, Philip G.; Spry, David J.; Trunek, Andrew J.; Evans, Laura J.; Chen, Liang-Yu; Hunter, Gary W.; Androjna, Drago

    2007-01-01

    This paper reports on initial results from the first device tested of a "second generation" Pt-SiC Schottky diode hydrogen gas sensor that: 1) resides on the top of atomically flat 4H-SiC webbed cantilevers, 2) has integrated heater resistor, and 3) is bonded and packaged. With proper selection of heater resistor and sensor diode biases, rapid detection of H2 down to concentrations of 20 ppm was achieved. A stable sensor current gain of 125 +/- 11 standard deviation was demonstrated during 250 hours of cyclic test exposures to 0.5% H2 and N2/air.

  18. 4H-SiC Schottky photodiodes for ultraviolet flame detection

    NASA Astrophysics Data System (ADS)

    Mazzillo, M.; Sciuto, A.

    2015-10-01

    In the last few years silicon carbide (SiC) has emerged as an appropriate material for the detection of very low ultraviolet photon fluxes even at elevated temperatures. In this paper we report on the electro-optical characteristics of large area interdigit Ni2Si/4H-SiC photodiodes in TO metal can package with a suitable molded cap quartz window with high transmission in the ultraviolet wavelength range. The detectors have been tested for the detection of the ultraviolet component of the yellow flame emitted by a small candle, showing good sensitivity for very weak photon fluxes notwithstanding the linear operation condition of the photodiodes.

  19. Dynamic characteristics of 4H-SiC drift step recovery diodes

    SciTech Connect

    Ivanov, P. A. Kon’kov, O. I.; Samsonova, T. P.; Potapov, A. S.; Grekhov, I. V.

    2015-11-15

    The dynamic characteristics of 4H-SiC p{sup +}–p–n{sub 0}–n{sup +} diodes are experimentally studied in the pulsed modes characteristic of the operation of drift step recovery diodes (DSRD-mode). The effect of the subnanosecond termination of the reverse current maintained by electron-hole plasma preliminarily pumped by a forward current pulse is analyzed in detail. The influence exerted on the DSRD effect by the amplitude of reverse-voltage pulses, the amplitude and duration of forward-current pulses, and the time delay between the forward and reverse pulses is demonstrated and accounted for.

  20. 4H-SiC JFET Multilayer Integrated Circuit Technologies Tested Up to 1000 K

    NASA Technical Reports Server (NTRS)

    Spry, D. J.; Neudeck, P. G.; Chen, L.; Chang, C. W.; Lukco, D.; Beheim, G. M.

    2015-01-01

    Testing of semiconductor electronics at temperatures above their designed operating envelope is recognized as vital to qualification and lifetime prediction of circuits. This work describes the high temperature electrical testing of prototype 4H silicon carbide (SiC) junction field effect transistor (JFET) integrated circuits (ICs) technology implemented with multilayer interconnects; these ICs are intended for prolonged operation at temperatures up to 773K (500 C). A 50 mm diameter sapphire wafer was used in place of the standard NASA packaging for this experiment. Testing was carried out between 300K (27 C) and 1150K (877 C) with successful electrical operation of all devices observed up to 1000K (727 C).

  1. Atomic oxidation of large area epitaxial graphene on 4H-SiC(0001)

    SciTech Connect

    Velez-Fort, E.; Ouerghi, A.; Silly, M. G.; Sirtti, F.; Eddrief, M.; Marangolo, M.; Shukla, A.

    2014-03-03

    Structural and electronic properties of epitaxial graphene on 4H-SiC were studied before and after an atomic oxidation process. X-ray photoemission spectroscopy indicates that oxygen penetrates into the substrate and decouples a part of the interface layer. Raman spectroscopy demonstrates the increase of defects due to the presence of oxygen. Interestingly, we observed on the near edge x-ray absorption fine structure spectra a splitting of the π* peak into two distinct resonances centered at 284.7 and 285.2 eV. This double structure smears out after the oxidation process and permits to probe the interface architecture between graphene and the substrate.

  2. Development of 17 kV 4H-SiC PiN diode

    NASA Astrophysics Data System (ADS)

    Runhua, Huang; Yonghong, Tao; Ling, Wang; Gang, Chen; Song, Bai; Rui, Li; Yun, Li; Zhifei, Zhao

    2016-08-01

    The design, fabrication, and electrical characteristics of a 4H-SiC PiN diode with breakdown voltage higher than 17 kV are presented. The three-zone JTE has been used in the fabrication. Numerical simulations have been performed to optimize the parameters of the edge termination technique. The epilayer properties of the N-type are 175 μm with a doping of 2 × 1014 cm-3. With the three-zone JTE, a typical breakdown voltage of 17 kV has been achieved. Project supported by the National High Technology Research and Development Program of China (No. 2014AA041401).

  3. Development of 17 kV 4H-SiC PiN diode

    NASA Astrophysics Data System (ADS)

    Runhua, Huang; Yonghong, Tao; Ling, Wang; Gang, Chen; Song, Bai; Rui, Li; Yun, Li; Zhifei, Zhao

    2016-08-01

    The design, fabrication, and electrical characteristics of a 4H-SiC PiN diode with breakdown voltage higher than 17 kV are presented. The three-zone JTE has been used in the fabrication. Numerical simulations have been performed to optimize the parameters of the edge termination technique. The epilayer properties of the N-type are 175 μm with a doping of 2 × 1014 cm‑3. With the three-zone JTE, a typical breakdown voltage of 17 kV has been achieved. Project supported by the National High Technology Research and Development Program of China (No. 2014AA041401).

  4. Nuclear shell evolution

    NASA Astrophysics Data System (ADS)

    Bentley, Ian

    2016-03-01

    The appearance and disappearance of nuclear shells and sub-shells has been at the forefront of recent nuclear theory and experimental efforts. This work extends a previously introduced method of structural analysis and applies it to protons in an attempt to provide a more complete understanding of shell structure in nuclei. Experimental observables including the mean square charge radius, as well as other spectroscopic and mass related quantities have been analyzed for shell structure features. A preliminary analysis using Nilsson coefficient fits of experimental quantities, such as odd mass spectra and B(E2) values, along isotopic chains will be discussed. The goal of this work is to provide a means of predicting shell structure far from stability. This work was supported by the National Science Foundation under Grants PHY1419765 and PHY0822648.

  5. Cohesive Elements for Shells

    NASA Technical Reports Server (NTRS)

    Davila, Carlos G.; Camanho, Pedro P.; Turon, Albert

    2007-01-01

    A cohesive element for shell analysis is presented. The element can be used to simulate the initiation and growth of delaminations between stacked, non-coincident layers of shell elements. The procedure to construct the element accounts for the thickness offset by applying the kinematic relations of shell deformation to transform the stiffness and internal force of a zero-thickness cohesive element such that interfacial continuity between the layers is enforced. The procedure is demonstrated by simulating the response and failure of the Mixed Mode Bending test and a skin-stiffener debond specimen. In addition, it is shown that stacks of shell elements can be used to create effective models to predict the inplane and delamination failure modes of thick components. The results indicate that simple shell models can retain many of the necessary predictive attributes of much more complex 3D models while providing the computational efficiency that is necessary for design.

  6. Carbonate mound evolution and coral diagenesis viewed by U-series dating of deep water corals

    NASA Astrophysics Data System (ADS)

    Frank, N.; Ricard, E.; Blamart, D.; van der Land, C.; Colin, C.; Foubert, A.; van Rooij, D.; van Weering, T.

    2007-12-01

    U-series dating of constructional deep sea corals is a powerful tool to reconstruct the evolution of carbonate mound sediments driven by coral growth, sediment trapping and diagenesis. Here we have investigated in great detail the time framework of constructional corals such as L. pertusa and M. oculata on 5 different mounds of the eastern North Atlantic (on Rockall Bank and in Porcupine Seabight) taken at variable depth and location (610 to 880m water depth). Periods favorable for coral growth are the Holocene and prior interglacials such as marine isotope stage 5 and 7, while glacial coral growth seems inhibited or extremely reduced. Coral development is almost continuous throughout the Holocene since mound re-colonization about 10,500 years ago. Mound accumulation rates vary between 20 and 220 cm/kyr determined from the coral age - depth relationship in each core. Those changes are most likely driven by changes between horizontal and vertical mound accumulation, food supply and ocean circulation. In addition, coral dating allowed to identify an important erosional event recorded in core MD01-2455G from Rockall Bank. Here a 1m thick sediment layer containing ancient corals likely from the start of Holocene re-colonization was displaced (collapsed) from further upslope on top of younger corals of ~2500 to 3000 years age. Prior to the initiation of coral growth diagenesis occurred frequently resulting in (1) the construction of so called carbonate hardgrounds and/or (2) the dissolution of the pre-Holocene coral framework. Solely, the deepest selected core in Porcupine Seabight (MD01-2463G at 880m depth) reveals coral re-colonization on an undisturbed ancient reef structure that dates back to 250,000 years. Diagenesis of earlier coral reef generations leading to coral dissolution leads to a loss of magnetic susceptibility and open system behavior of the coral skeletons with respect to U-series dating. While the processes causing such diagenetic layers are barely

  7. Pleistocene periglacial cryogenic mounds (lithalsas) on basalt plateaus in the western Pannonian Basin

    NASA Astrophysics Data System (ADS)

    Sebe, Krisztina; Csillag, Gábor

    2015-04-01

    On some basalt plateaus of the western Pannonian Basin, Hungary, fields of circular depressions occur. They are traditionally called "basalt karst' and their formation has been attributed either to collapse over karstifying rocks or to anthropogenic action (quarrying); however, both of these theories are questionable. The depressions are situated between elevations of 350-500 m a.s.l. and are characteristically surrounded by circular raised rims or ramparts. They measure a few m-s (up to ~10 m) in diameter, the ramparts emerge 0.5-1.5 m above the surrounding level ground and encircle a depression of 1-2 (-3) m deep in the middle. Depressions cluster in well delineated, high-density groups, with individual fields containing several dozens of these forms. Neighbouring ramparts are tightly packed, often interfere and depressions can thus coalesce creating composite forms. The ramparts are composed of coarse (dm-sized) basalt blocks, whose material is identical to that of the surrounding terrain and seems to originate from the depression. Many of the depressions host ephemeral ponds. Raised rims exclude formation of these landforms by any karstic processes. The anthropogenic theory is opposed by the lack of the remains of any facilities (e.g. roads), of tools and by the very illogical distribution and geometry of depressions from the point of human use. On the contrary, we interpret these ramparted depressions as being of periglacial origin, remnants of cryogenic mounds. The central depression and the emergent rampart can be well explained by the ice core raising the overlying rock and by the radial downsliding of this material on the ice core to the margins. Within cryogenic mounds, clustering and size of the forms fits the characteristics of perennial frost mound without peat cover, i.e. lithalsas or minerogenic palsas. Cryogenic mounds are important paleoclimatic indicators. Based on modern analogs, these lithalsa scars indicate the former presence of discontinuous

  8. POTENTIAL IMPACT OF BLENDING RESIDUAL SOLIDS FROM TANKS 18/19 MOUNDS WITH TANK 7 OPERATIONS

    SciTech Connect

    Eibling, R; Erich Hansen, E; Bradley Pickenheim, B

    2007-03-29

    High level waste tanks 18F and 19F have residual mounds of waste which may require removal before the tanks can be closed. Conventional slurry pump technology, previously used for waste removal and tank cleaning, has been incapable of removing theses mounds from tanks 18F and 19F. A mechanical cleaning method has been identified that is potentially capable of removing and transferring the mound material to tank 7F for incorporation in a sludge batch for eventual disposal in high level waste glass by the Defense Waste Processing Facility. The Savannah River National Laboratory has been requested to evaluate whether the material transferred from tanks 18F/19F by the mechanical cleaning technology can later be suspended in Tank 7F by conventional slurry pumps after mixing with high level waste sludge. The proposed mechanical cleaning process for removing the waste mounds from tanks 18 and 19 may utilize a high pressure water jet-eductor that creates a vacuum to mobilize solids. The high pressure jet is also used to transport the suspended solids. The jet-eductor system will be mounted on a mechanical crawler for movement around the bottom of tanks 18 and 19. Based on physical chemical property testing of the jet-eductor system processed IE-95 zeolite and size-reduced IE-95 zeolite, the following conclusions were made: (1) The jet-eductor system processed zeolite has a mean and median particle size (volume basis) of 115.4 and 43.3 microns in water. Preferential settling of these large particles is likely. (2) The jet-eductor system processed zeolite rapidly generates settled solid yield stresses in excess of 11,000 Pascals in caustic supernates and will not be easily retrieved from Tank 7 with the existing slurry pump technology. (3) Settled size-reduced IE-95 zeolite (less than 38 microns) in caustic supernate does not generate yield stresses in excess of 600 Pascals in less than 30 days. (4) Preferential settling of size-reduced zeolite is a function of the amount of

  9. Complete genome sequence of the marine, cellulose and xylan degrading bacterium Glaciecola sp. 4H-3-7+YE-5

    SciTech Connect

    Klippel, Dr Barbara; Bruce, David; Davenport, Karen W.; Goodwin, Lynne A.; Han, James; Han, Shunsheng; Land, Miriam L; Mikhailova, Natalia; Nolan, Matt; Pennacchio, Len; Pitluck, Sam; Tapia, Roxanne; Woyke, Tanja; Wiebusch, Sigrid; Basner, Alexander; Abe, Fumiyoshi; Horikoshi, Koki; Antranikian, Garabed

    2011-01-01

    Glaciecola sp. 4H-3-7+YE-5 was isolated from deep sea sediments at Suruga Bay in Japan and is capable of efficiently hydrolyzing cellulose and xylan. The complete genome sequence of Glaciecola sp. 4H-3-7+YE-5 revealed several genes encoding putatively novel glycoside hydrolases associated with plant biomass degradation.

  10. A Mixed Method Study of Positional Leadership of North Dakota 4-H Ambassador and State FFA Officer Alumni

    ERIC Educational Resources Information Center

    Peterson, Nels Milan

    2010-01-01

    The purpose of this mixed method study was to determine the positional leadership of North Dakota 4-H and FFA leadership alumni. This study determined the influence of youth development programs on statewide leadership alumni (those who served from 1970 to 2000) and community leadership roles as adults. Former North Dakota 4-H Ambassador Alumni…

  11. Understanding Life Skills Gained from and Reasons for Youth Participation in the Tennessee 4-H Sheep Skillathon

    ERIC Educational Resources Information Center

    Davis, Terra Kimes; Stripling, Christopher T.; Stephens, Carrie A.; Loveday, H. Dwight

    2016-01-01

    The high number of U.S. youth exhibiting at-risk behavior points to a lack of life skills development. We determined the effects of participating in one state's 4-H sheep skillathon on youths' life skills development and the youths' reasons for participating. The target population was 2014 Tennessee 4-H Sheep Skillathon participants (N = 153), and…

  12. Eat, Grow, Lead 4-H: An Innovative Approach to Deliver Campus- Based Field Experiences to Pre-Entry Extension Educators

    ERIC Educational Resources Information Center

    Weeks, Penny Pennington; Weeks, William G.

    2012-01-01

    Eat, Grow, Lead 4-H Club was created as a pilot program for college students seeking to gain experience as non-formal youth educators, specifically serving pre-entry level Extension educators through a university-based 4-H club. Seventeen student volunteers contributed an estimated 630 hours of service to the club during spring 2011. The club…

  13. Family Diversity in a Youth Organization: Involvement of Single-Parent Families and Stepfamilies in 4-H.

    ERIC Educational Resources Information Center

    Ganong, Lawrence H.

    1993-01-01

    Evaluated involvement of children from single-parent and stepparent households in 4-H clubs. Used case study approach, with data collected via written materials; interviews with 4-H staff; and mailed questionnaires from professional staff, paraprofessionals, and parents. Children from single-parent households were found to be underrepresented, as…

  14. Effect of Doping Concentration Variations in PVT-Grown 4H-SiC Wafers

    NASA Astrophysics Data System (ADS)

    Yang, Yu; Guo, Jianqiu; Goue, Ouloide; Raghothamachar, Balaji; Dudley, Michael; Chung, Gil; Sanchez, Edward; Quast, Jeff; Manning, Ian; Hansen, Darren

    2016-04-01

    Synchrotron white beam x-ray topography studies carried out on 4H-SiC wafers characterized by locally varying doping concentrations reveals the presence of overlapping Shockley stacking faults generated from residual surface scratches in regions of higher doping concentrations after the wafers have been subjected to heat treatment. The stacking faults are rhombus-shaped and bound by Shockley partial dislocations. The fault generation process is driven by the fact that in regions of higher doping concentrations, a faulted crystal containing double Shockley faults is more stable than a perfect 4H-SiC crystal at the high temperatures (>1000°C) that the wafers are subject to during heat treatment. We have developed a model for the formation mechanism of the rhombus-shaped stacking faults. Our studies show that during heat treatment of the wafer, such double Shockley faults can be generated in regions where dislocation sources are presents (e.g. scratches or low-angle boundaries) and when the nitrogen doping concentration exceeds a certain level.

  15. Evaluation of 4H-SiC Thermal Oxide Reliability Using Area-Scaling Method

    NASA Astrophysics Data System (ADS)

    Senzaki, Junji; Shimozato, Atsushi; Okamoto, Mitsuo; Kojima, Kazutoshi; Fukuda, Kenji; Okumura, Hajime; Arai, Kazuo

    2009-08-01

    The reliability of thermal oxides grown on an n-type 4H-SiC(0001) was investigated using an area-scaling method, and the influence of dislocation defects on the time-dependent dielectric breakdown characteristics of thermal oxides was examined. A thermal oxide was grown by dry oxidation at 1200 °C followed by nitrogen post-oxidation annealing. Using the area-scaling method, the time-to-breakdown (tBD) distribution curves of metal-oxide-semiconductor (MOS) capacitors with different gate area sizes were converged to a single one. It was clearly shown that origins of dielectric breakdown are edge breakdown and dislocation-related breakdown for steep and gradual slopes of the area-scaling normalized tBD distribution curve, respectively. In addition, a yield analysis of MOS capacitors quantitatively indicated that both threading screw dislocation and basal plane dislocation are predominant killer defects for the dielectric breakdown of thermal oxides on the 4H-SiC(0001) face.

  16. Characterization of V-shaped defects in 4H-SiC homoepitaxial layers

    DOE PAGESBeta

    Zhang, Lihua; Su, Dong; Kisslinger, Kim; Stach, Eric; Chung, Gil; Zhang, Jie; Thomas, Bernd; Sanchez, Edward K; Mueller, Stephan G.; Hansen, Darren; et al

    2014-12-04

    Synchrotron white beam x-ray topography images show that faint needle-like surface morphological features observed on the Si-face of 4H-SiC homoepitaxial layers using Nomarski optical microscopy are associated with V shaped stacking faults in the epilayer. KOH etching of the V shaped defect reveals small oval pits connected by a shallow line which corresponding to the surface intersections of two partial dislocations and the stacking fault connecting them. Transmission electron microscopy (TEM) specimens from regions containing the V shaped defects were prepared using focused ion beam milling, and stacking sequences of (85), (50) and (63) are observed at the faulted regionmore » with high resolution TEM. In order to study the formation mechanism of V shaped defect, low dislocation density 4H-SiC substrates were chosen for epitaxial growth, and the corresponding regions before and after epitaxy growth are compared in SWBXT images. It is found that no defects in the substrate are directly associated with the formation of the V shaped defect. Simulation results of the contrast from the two partial dislocations associated with V shaped defect in synchrotron monochromatic beam x-ray topography reveals the opposite sign nature of their Burgers vectors. Therefore, a mechanism of 2D nucleation during epitaxy growth is postulated for the formation of the V shaped defect, which requires elimination of non-sequential 1/4[0001] bilayers from the original structure to create the observed faulted stacking sequence.« less

  17. Characterization of V-shaped defects in 4H-SiC homoepitaxial layers

    SciTech Connect

    Zhang, Lihua; Su, Dong; Kisslinger, Kim; Stach, Eric; Chung, Gil; Zhang, Jie; Thomas, Bernd; Sanchez, Edward K; Mueller, Stephan G.; Hansen, Darren; Loboda, Mark J.; Wu, Fangzhen; Wang, Huanhuan; Raghothamachar, Balaji; Dudley, Michael

    2014-12-04

    Synchrotron white beam x-ray topography images show that faint needle-like surface morphological features observed on the Si-face of 4H-SiC homoepitaxial layers using Nomarski optical microscopy are associated with V shaped stacking faults in the epilayer. KOH etching of the V shaped defect reveals small oval pits connected by a shallow line which corresponding to the surface intersections of two partial dislocations and the stacking fault connecting them. Transmission electron microscopy (TEM) specimens from regions containing the V shaped defects were prepared using focused ion beam milling, and stacking sequences of (85), (50) and (63) are observed at the faulted region with high resolution TEM. In order to study the formation mechanism of V shaped defect, low dislocation density 4H-SiC substrates were chosen for epitaxial growth, and the corresponding regions before and after epitaxy growth are compared in SWBXT images. It is found that no defects in the substrate are directly associated with the formation of the V shaped defect. Simulation results of the contrast from the two partial dislocations associated with V shaped defect in synchrotron monochromatic beam x-ray topography reveals the opposite sign nature of their Burgers vectors. Therefore, a mechanism of 2D nucleation during epitaxy growth is postulated for the formation of the V shaped defect, which requires elimination of non-sequential 1/4[0001] bilayers from the original structure to create the observed faulted stacking sequence.

  18. Exploration of Defects in 4H-SiC MOSFETs via Spin Dependent Charge Pumping

    NASA Astrophysics Data System (ADS)

    Anders, Mark; Lenahan, Patrick; Lelis, Aivars

    4H-SiC MOSFETs have great promise for use in high temperature and high voltage applications. Unfortunately, defects at the SiC/SiO2 interface reduce the performance of these devices. Previously, our group utilized electrically detected magnetic resonance (EDMR) detected via spin dependent recombination (SDR) to identify such SiC/SiO2 interface defects utilizing the bipolar amplification (BAE) biasing scheme; we observed SiC silicon vacancies, E-prime centers, and hydrogen complexed E-prime centers. All of these defects must have levels around the middle of the SiC band gap because they are effective recombination centers. We expanded our studies to include EDMR detection via spin dependent charge pumping (SDCP) at low field, X band, and K band, allowing EDMR exploration of nearly the entire 4H-SiC band gap. Perhaps the most important finding of the (nearly) full band gap measurements is the absence of the carbon dangling bond spectrum in the SDCP. Additionally, in nMOSFETs, we observe an SDCP EDMR spectrum dominated by a silicon vacancy, whereas in pMOSFETs, we also observe a strong, nearly isotropic single line spectrum with g = 2.00244 and 2.00248 when the c-axis is nearly parallel and perpendicular to the magnetic field, respectively. The results suggest that silicon vacancy centers dominate nMOSFET interfaces whereas additional defects clearly play important roles in pMOSFETs.

  19. n-ZnO/p-4H-SiC diode: Structural, electrical, and photoresponse characteristics

    SciTech Connect

    Guziewicz, M. Jung, W.

    2015-09-07

    Epitaxial n-type ZnO film has been grown, on a commercial 5 μm thick p-type 4H-SiC(00.1) Al doped epilayer, by atomic layer deposition. A full width at half maximum of the ZnO 00.2 diffraction peak rocking curve of 0.34°{sup  }± 0.02° has been measured. Diodes formed on the n-ZnO/p-4H-SiC heterostructure show rectifying behavior with a forward to reverse current ratio at the level of 10{sup 9} at ±4 V, a leakage current density of ∼6 × 10{sup −8} A/cm{sup 2}, and a low ideality factor equal to 1.17 ± 0.04. In addition, the diodes exhibit selective photoresponse with a maximum at 367 nm, and with a current increase of ∼10{sup 3} under illuminations with respect to the dark value, which makes such devices prospective candidates for ultraviolet light sensors.

  20. Comprehensive study of a 4H-SiC MES-MOSFET

    NASA Astrophysics Data System (ADS)

    Jamali Mahabadi, S. E.; Amini Moghadam, Hamid

    2015-11-01

    In this paper, we studied the enhancement of the breakdown voltage in the 4H-SiC MESFET-MOSFET (MES-MOSFET) structure which we have proposed in our previous work. We compared this structure with Conventional Bulk-MOSFET (CB-MOSFET) and Field plated Conventional Bulk-MOSFET (FCB-MOSFET) structures. The 4H-SiC MES-MOSFET structure consists of two additional schottky buried gates which behave like a Metal on Semiconductor (MES) at the interface of the active region and substrate. The motivation for this structure was to enhance the breakdown voltage by introducing a new technique of utilizing the reduced surface field (RESURF) concept. In our comparison and investigation we used a two-dimensional device simulator. Our simulation results show that the breakdown voltage of the proposed structure is 3.7 and 2.9 times larger than CB-MOSFET and FCB-MOSFET structures, respectively. We also showed that the threshold voltage and the slope of drain current (ID) as a function of drain-source voltage (VDS) for all the structures is the same.

  1. Characterization of the Minimum Energy Paths for the Ring Closure Reactions of C4H3 with Acetylene

    NASA Technical Reports Server (NTRS)

    Walch, Stephen P.

    1995-01-01

    The ring closure reaction of C4H3 with acetylene to give phenyl radical is one proposed mechanism for the formation of the first aromatic ring in hydrocarbon combustion. There are two low-lying isomers of C4H3; 1-dehydro-buta-l-ene-3-yne (n-C4H3) and 2-dehydro-buta-l-ene-3-yne (iso-C4H3). It has been proposed that only n-C4H3 reacts with acetylene to give phenyl radical, and since iso-C4H3 is more stable than n-C4H3, formation of phenyl radical by this mechanism is unlikely. We report restricted Hartree-Fock (RHF) plus singles and doubles configuration interaction calculations with a Davidson's correction (RHF+1+2+Q) using the Dunning correlation consistent polarized valence double zeta basis set (cc-pVDZ) for stationary point structures along the reaction pathway for the reactions of n-C4H3 and iso-C4H3 with acetylene. n-C4H3 plus acetylene (9.4) has a small entrance channel barrier (17.7) (all energetics in parentheses are in kcal/mol with respect to iso-C4H3 plus acetylene) and the subsequent closure steps leading to phenyl radical (-91.9) are downhill with respect to the entrance channel barrier. Iso-C4H3 Plus acetylene also has an entrance channel barrier (14.9) and there is a downhill pathway to 1-dehydro-fulvene (-55.0). 1-dehydro-fulvene can rearrange to 6-dehydro-fulvene (-60.3) by a 1,3-hydrogen shift over a barrier (4.0), which is still below the entrance channel barrier, from which rearrangement to phenyl radical can occur by a downhill pathway. Thus, both n-C4H3 and iso-C4H3 can react with acetylene to give phenyl radical with small barriers.

  2. [Spatial pattern of sand-mound of Nitraria in different habitat at the southeastern fringe of the Tengger desert].

    PubMed

    Jia, Xiao-Hong; Li, Xin-Rong

    2008-07-01

    Based on the geo-statistics and quantitative ecology method, the spatial pattern of sand-mound of Nitraria was been analyzed in different habitat at the southeastern fringe of the Tengger desert in order to keep the natural mounds stability and ecological efficiency. The results showed that the different groundwater level and plant growth condition resulted in difference of Nitraria population at capacity of withstanding sand bury and the effect of sand-binding. The coverage, density and biomass of Nitraria population at the lacustrine basin lowland were significant higher than those of the alluvial fan (p < 0.01). Although the height of Nitraria population at the lacustrine basin lowland was lower than that of the alluvial fan, there was no significant difference between two habitat (p > 0.05). The height and volume of sand-mound was 1.20 m and 88.19 m3 at the lacustrine basin lowland, 1.14 m and 33.16 m3 at the alluvial fan, respectively. The size and distribution of sand-mound was significant difference at different habitat (p < 0.01). The mound of the lacustrine basin lowland has the tendency of large patch and low density, developed longer scale pattern in auto-correlated distance, and those of the alluvial fan just the reverse. The spatial heterogeneity of mound size and volume of accumulation sand in the lacustrine basin lowland can be controlled by auto-correlated factors at 1.2-84 m scale, and the random factors at under 100 m controlled the spatial heterogeneity in the alluvial fan. Especially, the size and volume of sand-mound has constant variation at under the 100 m scale in the alluvial fan, and has random spatial pattern without law. PMID:18828398

  3. Paleoenvironmental reconstruction of microbial mud mound derived boulders from gravity-flow polymictic megabreccias (Visean, SW Spain)

    NASA Astrophysics Data System (ADS)

    Rodríguez-Martínez, M.; Moreno-González, I.; Mas, R.; Reitner, J.

    2012-07-01

    The Upper Visean outcrops from the Guadiato Valley (Córdoba, SW Spain) provide a well-preserved record of the mud mound factory, which was developed in a mainly siliciclastic synorogenic foreland basin during the oblique sinistral collision of two terranes (Ossa Morena and Central Iberian blocks). The first onset of mud mound development has been recorded as microbial mud mound-derived boulders in polymictic megabreccias as result of strong tectonic activity. The Upper Visean record from the Mississippian central band at Guadiato Valley starts with lower heterolithic units (up to 180 m thick) and shows two major tectonically-controlled cycles: a fining upwards interval (FU) followed by a coarsening upwards interval (CU). These cycles are linked to two active margins with gravelly fan delta development and different source areas. Mud mound-derived boulders occur in the CU interval and are formed by peloidal primary and secondary (reworked) automicrites and allomicrites, showing a diverse faunal and floral assemblage, although never as the main skeletal framebuilders. However, the observed coeval richness in sponges (lyssacinose hexactinellids and non-lithistid demosponges) and the diverse calcareous algae assemblage in mud mound derived boulders are not common in other Visean buildups. The growth cavities display changes in the geopetal relationships between fillings and the secondary cavities containing sand to gravel fillings reflecting a complex pre-boulder and mud mound derived boulder history. Detailed mapping, sampling, stratigraphic and microfacial analyses have allowed the reconstruction of the mud mounds sedimentary environment prior to the collapse, transport and emplacement as boulders with polymictic gravels.

  4. NMR and ESR characterization of activated carbons produced from pecan shells

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A large number of solid-state NMR and ESR experiments were explored as potential tools to study chemical structure, mobility, and pore volume of activated carbon. We used a model system where pecan shells were activated with phosphoric acid, and carbonized at 450ºC for 4 h with varying amounts of ai...

  5. Models of formation and activity of spring mounds in the mechertate-chrita-sidi el hani system, eastern Tunisia: implications for the habitability of Mars.

    PubMed

    Essefi, Elhoucine; Komatsu, Goro; Fairén, Alberto G; Chan, Marjorie A; Yaich, Chokri

    2014-01-01

    Spring mounds on Earth and on Mars could represent optimal niches of life development. If life ever occurred on Mars, ancient spring deposits would be excellent localities to search for morphological or chemical remnants of an ancient biosphere. In this work, we investigate models of formation and activity of well-exposed spring mounds in the Mechertate-Chrita-Sidi El Hani (MCSH) system, eastern Tunisia. We then use these models to explore possible spring mound formation on Mars. In the MCSH system, the genesis of the spring mounds is a direct consequence of groundwater upwelling, triggered by tectonics and/or hydraulics. As they are oriented preferentially along faults, they can be considered as fault spring mounds, implying a tectonic influence in their formation process. However, the hydraulic pressure generated by the convergence of aquifers towards the surface of the system also allows consideration of an origin as artesian spring mounds. In the case of the MCSH system, our geologic data presented here show that both models are valid, and we propose a combined hydro-tectonic model as the likely formation mechanism of artesian-fault spring mounds. During their evolution from the embryonic (early) to the islet ("island") stages, spring mounds are also shaped by eolian accumulations and induration processes. Similarly, spring mounds have been suggested to be relatively common in certain provinces on the Martian surface, but their mode of formation is still a matter of debate. We propose that the tectonic, hydraulic, and combined hydro-tectonic models describing the spring mounds at MCSH could be relevant as Martian analogs because: (i) the Martian subsurface may be over pressured, potentially expelling mineral-enriched waters as spring mounds on the surface; (ii) the Martian subsurface may be fractured, causing alignment of the spring mounds in preferential orientations; and (iii) indurated eolian sedimentation and erosional remnants are common features on Mars

  6. Models of Formation and Activity of Spring Mounds in the Mechertate-Chrita-Sidi El Hani System, Eastern Tunisia: Implications for the Habitability of Mars

    PubMed Central

    Essefi, Elhoucine; Komatsu, Goro; Fairén, Alberto G.; Chan, Marjorie A.; Yaich, Chokri

    2014-01-01

    Spring mounds on Earth and on Mars could represent optimal niches of life development. If life ever occurred on Mars, ancient spring deposits would be excellent localities to search for morphological or chemical remnants of an ancient biosphere. In this work, we investigate models of formation and activity of well-exposed spring mounds in the Mechertate-Chrita-Sidi El Hani (MCSH) system, eastern Tunisia. We then use these models to explore possible spring mound formation on Mars. In the MCSH system, the genesis of the spring mounds is a direct consequence of groundwater upwelling, triggered by tectonics and/or hydraulics. As they are oriented preferentially along faults, they can be considered as fault spring mounds, implying a tectonic influence in their formation process. However, the hydraulic pressure generated by the convergence of aquifers towards the surface of the system also allows consideration of an origin as artesian spring mounds. In the case of the MCSH system, our geologic data presented here show that both models are valid, and we propose a combined hydro-tectonic model as the likely formation mechanism of artesian-fault spring mounds. During their evolution from the embryonic (early) to the islet (“island”) stages, spring mounds are also shaped by eolian accumulations and induration processes. Similarly, spring mounds have been suggested to be relatively common in certain provinces on the Martian surface, but their mode of formation is still a matter of debate. We propose that the tectonic, hydraulic, and combined hydro-tectonic models describing the spring mounds at MCSH could be relevant as Martian analogs because: (i) the Martian subsurface may be over pressured, potentially expelling mineral-enriched waters as spring mounds on the surface; (ii) the Martian subsurface may be fractured, causing alignment of the spring mounds in preferential orientations; and (iii) indurated eolian sedimentation and erosional remnants are common features on

  7. Stratigraphy and petrology of petroleum-producing Waulsortian-type carbonate mounds in Fort Payne formation (Lower Mississippian) of north-central Tennessee

    SciTech Connect

    MacQuown, W.C.; Perkins, J.H.

    1982-08-01

    The petroleum-producing subsurface mounds of the Fort Payne Formation (Lower Mississippian) in north-central Tennessee represent a facies that is generally absent or poorly developed in surface sections to the west, near the Cincinnati arch, and to the east, in the Appalachian fold belt. The cross section and isopach maps of the Fort Payne mound unit and submound unit, and a structural map of the underlying Chattanooga Shale provide evidence for predicting undiscovered mounds by interpolating and extrapolating along several northeast-southwest mound trends. Interpretations are based on subsurface data, and they are reinforced by a comparison with the analogous Waulsortian mounds and lenses of the same age in Europe. Waulsortian-type mounds are widespread on the surface of western Europe and North America. However, differences in morphology, porosity development, and the emplacement of petroleum in Fort Payne mounds are related to local paleogeography in a shallow cratonic-shelf sea subjected to cyclic regression and transgression due to regional tectono-eustatic events. Fort Payne mounds produced more than 5.5 million bbl of oil through 1980. Although the source beds have not been identified, petroleum may have been derived from the submound or mound units of the Fort Payne Formation, or from the underlying Chattanooga Shale.

  8. Models of formation and activity of spring mounds in the mechertate-chrita-sidi el hani system, eastern Tunisia: implications for the habitability of Mars.

    PubMed

    Essefi, Elhoucine; Komatsu, Goro; Fairén, Alberto G; Chan, Marjorie A; Yaich, Chokri

    2014-01-01

    Spring mounds on Earth and on Mars could represent optimal niches of life development. If life ever occurred on Mars, ancient spring deposits would be excellent localities to search for morphological or chemical remnants of an ancient biosphere. In this work, we investigate models of formation and activity of well-exposed spring mounds in the Mechertate-Chrita-Sidi El Hani (MCSH) system, eastern Tunisia. We then use these models to explore possible spring mound formation on Mars. In the MCSH system, the genesis of the spring mounds is a direct consequence of groundwater upwelling, triggered by tectonics and/or hydraulics. As they are oriented preferentially along faults, they can be considered as fault spring mounds, implying a tectonic influence in their formation process. However, the hydraulic pressure generated by the convergence of aquifers towards the surface of the system also allows consideration of an origin as artesian spring mounds. In the case of the MCSH system, our geologic data presented here show that both models are valid, and we propose a combined hydro-tectonic model as the likely formation mechanism of artesian-fault spring mounds. During their evolution from the embryonic (early) to the islet ("island") stages, spring mounds are also shaped by eolian accumulations and induration processes. Similarly, spring mounds have been suggested to be relatively common in certain provinces on the Martian surface, but their mode of formation is still a matter of debate. We propose that the tectonic, hydraulic, and combined hydro-tectonic models describing the spring mounds at MCSH could be relevant as Martian analogs because: (i) the Martian subsurface may be over pressured, potentially expelling mineral-enriched waters as spring mounds on the surface; (ii) the Martian subsurface may be fractured, causing alignment of the spring mounds in preferential orientations; and (iii) indurated eolian sedimentation and erosional remnants are common features on Mars

  9. Failure of Viral Shells

    NASA Astrophysics Data System (ADS)

    Klug, William S.; Bruinsma, Robijn F.; Michel, Jean-Philippe; Knobler, Charles M.; Ivanovska, Irena L.; Schmidt, Christoph F.; Wuite, Gijs J. L.

    2006-12-01

    We report a combined theoretical and experimental study of the structural failure of viral shells under mechanical stress. We find that discontinuities in the force-indentation curve associated with failure should appear when the so-called Föppl von Kármán (FvK) number exceeds a critical value. A nanoindentation study of a viral shell subject to a soft-mode instability, where the stiffness of the shell decreases with increasing pH, confirms the predicted onset of failure as a function of the FvK number.

  10. Plasma ignition and steady state simulations of the Linac4 H{sup −} ion source

    SciTech Connect

    Mattei, S. Lettry, J.; Grudiev, A.; Ohta, M.; Yasumoto, M.; Hatayama, A.

    2014-02-15

    The RF heating of the plasma in the Linac4 H{sup −} ion source has been simulated using a particle-in-cell Monte Carlo collision method. This model is applied to investigate the plasma formation starting from an initial low electron density of 10{sup 12} m{sup −3} and its stabilization at 10{sup 18} m{sup −3}. The plasma discharge at low electron density is driven by the capacitive coupling with the electric field generated by the antenna, and as the electron density increases the capacitive electric field is shielded by the plasma and induction drives the plasma heating process. Plasma properties such as e{sup −}/ion densities and energies, sheath formation, and shielding effect are presented and provide insight to the plasma properties of the hydrogen plasma.

  11. Evaluation of MOS structures processed on 4H SiC layers grown by PVT epitaxy

    NASA Astrophysics Data System (ADS)

    Ciechonski, R. R.; Syväjärvi, M.; Wahab, Q.; Yakimova, R.

    2005-12-01

    MOS capacitors have been fabricated on 4H-SiC epilayers grown by physical vapor transport (PVT) epitaxy. The properties were compared with those on similar structures based on chemical vapor deposition (CVD) layers. Capacitance-voltage ( C- V) and conductance measurements ( G- V) were performed in the frequency range of 1 kHz to 1 MHz and also at temperatures up to 475 K. Detailed investigations of the PVT structures indicate a stable behaviour of the interface traps from room temperature up to 475 K. The amount of positive oxide charge QO is 6.83 × 10 9 cm -2 at room temperature and decreases with temperature increase. This suggests that the processed devices are temperature stable. The density of interface states Dit obtained by Nicollian-Brews conductance method is lower in the structure based on the PVT grown sample.

  12. Band gap states of Ti, V, and Cr in 4H-silicon carbide

    NASA Astrophysics Data System (ADS)

    Achtziger, Norbert; Witthuhn, Wolfgang

    1997-07-01

    Band gap states of Ti, V, and Cr in n-type 4H-SiC were investigated by radiotracer deep level transient spectroscopy (DLTS). Doping with the radioactive isotopes 48V and 51Cr was done by recoil implantation followed by annealing (1600 K). Repeated DLTS measurements during the elemental transmutation of these isotopes to 48Ti and 51V, respectively, reveal the corresponding concentration changes of band gap states. Thus, six levels are identified in the band gap: Cr levels at 0.15, 0.18, and 0.74 eV, one V level at 0.97 eV, and two Ti levels at 0.13 and 0.17 eV below the conduction band edge.

  13. 4H-SiC UV Photo Detector with Large Area and Very High Specific Detectivity

    NASA Technical Reports Server (NTRS)

    Yan, Feng; Shahid, Aslam; Franz, David; Xin, Xiaobin; Zhao, Jian H.; Zhao, Yuegang; Winer, Maurice

    2004-01-01

    Pt/4H-SiC Schottky photodiodes have been fabricated with the device areas up to 1 sq cm. The I-V characteristics and photo-response spectra have been measured and analyzed. For a 5 mm x 5 mm area device leakage current of 1 x 10(exp 15)A at zero bias and 1.2 x 10(exp 14)A at -IV have been established. The quantum efficiency is over 30% from 240nm to 320nm. The specific detectivity, D(sup *), has been calculated from the directly measured leakage current and quantum efficiency data and are shown to be higher than 10(exp 15) cmHz(sup 1/2)/W from 210nm to 350nm with a peak D(sup *) of 3.6 x 10(exp 15)cmH(sup 1/2)/W at 300nm.

  14. Excess leakage currents in high-voltage 4H-SiC Schottky diodes

    SciTech Connect

    Ivanov, P. A. Grekhov, I. V.; Potapov, A. S.; Samsonova, T. P.; Il'inskaya, N. D.; Kon'kov, O. I.; Serebrennikova, O. Yu.

    2010-05-15

    The high-voltage 4H-SiC Schottky diodes are fabricated with a nickel barrier and a guard system in the form of 'floating' planar p-n junctions. The analysis of I-V characteristics measured in a wide temperature range shows that the forward current is caused by thermionic emission; however, the current is 'excessive' in the reverse direction. It is assumed that the reverse current flows locally through the points of the penetrating-dislocation outcrop to the Ni-SiC interface. The shape of reverse I-V characteristics makes it possible to conclude that the electron transport is governed by the monopolar-injection mechanism (the space-charge limited current) with participation of capture traps.

  15. Characterization and Modeling of 4H-SiC Lateral MOSFETs for Integrated Circuit Design

    SciTech Connect

    Mudholkar, M; Mantooth, HA

    2013-06-01

    A new process in 4H-SiC is developed that features n-type buried and inversion channel lateral MOSFETs that are fabricated with several different channel lengths (2-8 mu m) and widths (8-32 mu m) and characterized over a wide temperature range (25 degrees C-225 degrees C). It is shown that the on-resistance of enhancement-mode SiC MOSFETs reduces with temperature despite a reduction in inversion mobility because of the interaction of interface states with temperature. To enable integrated circuit development using the developed MOSFETs, their electrical characteristics are modeled over geometry and temperature using the industry standard PSP MOSFET model. A new mathematical formulation to describe the presence of the interface states is also developed and implemented in the PSP model, and excellent agreement is shown between measurement and simulation using the modified PSP model.

  16. Evidence for near-infrared photoluminescence of nitrogen vacancy centers in 4 H -SiC

    NASA Astrophysics Data System (ADS)

    Zargaleh, S. A.; Eble, B.; Hameau, S.; Cantin, J.-L.; Legrand, L.; Bernard, M.; Margaillan, F.; Lauret, J.-S.; Roch, J.-F.; von Bardeleben, H. J.; Rauls, E.; Gerstmann, U.; Treussart, F.

    2016-08-01

    We present evidence of near-infrared photoluminescence (PL) signature of nitrogen vacancy centers (NCVSi) - in silicon carbide (SiC). This center exhibits an S =1 ground state spin similar to the NV- center in diamond. We have performed photoluminescence excitation measurements at cryogenic temperature and demonstrated efficient photoexcitation of distinct photoluminescence from (NCVSi)- in 4 H -SiC. Furthermore, by correlating the energies of measured zero phonon lines (ZPLs) with theoretical values derived from hybrid density functional theory each of the ZPLs has been associated to the respective occupation of hexagonal (h ) and quasicubic (k ) lattice sites in close analogy to neutral divacancy centers (VCVSi) 0 in the same material. Finally, with the appropriate choice of excitation energy we demonstrated the selective excitation of (NCVSi) - PL with no contamination by (VCVSi) 0 PL, thereby opening the way towards the optical detection of (NCVSi) - electron spin resonance.

  17. Irradiation of 4H-SiC UV detectors with heavy ions

    SciTech Connect

    Kalinina, E. V. Lebedev, A. A.; Bogdanova, E.; Berenquier, B.; Ottaviani, L.; Violina, G. N.; Skuratov, V. A.

    2015-04-15

    Ultraviolet (UV) photodetectors based on Schottky barriers to 4H-SiC are formed on lightly doped n-type epitaxial layers grown by the chemical vapor deposition method on commercial substrates. The diode structures are irradiated at 25°C by 167-MeV Xe ions with a mass of 131 amu at a fluence of 6 × 10{sup 9} cm{sup −2}. Comparative studies of the optical and electrical properties of as-grown and irradiated structures with Schottky barriers are carried out in the temperature range 23–180°C. The specific features of changes in the photosensitivity and electrical characteristics of the detector structures are accounted for by the capture of photogenerated carriers into traps formed due to fluctuations of the conduction-band bottom and valence-band top, with subsequent thermal dissociation.

  18. An Integrated Gate Driver in 4H-SiC for Power Converter Applications

    SciTech Connect

    Ericson, Milton Nance; Frank, Steven Shane; Britton, Charles; Janke, Devon D; Ezell, N Dianne Bull; Ryu, Sei_Hyung; Mantooth, Alan; Francis, Dr. Matt; Lanmichhane, Dr. Ranjan; Shepherd, Dr. Paul; Glover, Dr. Michael; Whitaker, Mr. Bret; Cole, Mr. Zach; Passmore, Mr. Brandon; Mcnutt, Tyler

    2014-01-01

    A gate driver fabricated in a 2-um 4H silicon carbide (SiC) process is presented. This process was optimized for vertical power MOSFET fabrication but accommodated integration of a few low-voltage device types including N-channel MOSFETs, resistors, and capacitors. The gate driver topology employed incorporates an input level translator, variable power connections, and separate power supply connectivity allowing selection of the output signal drive amplitude. The output stage utilizes a source follower pull-up device that is both overdriven and body source connected to improve rise time behavior. Full characterization of this design driving a SiC power MOSFET is presented including rise and fall times, propagation delays, and power consumption. All parameters were measured to elevated temperatures exceeding 300 C. Details of the custom test system hardware and software utilized for gate driver testing are also provided.

  19. Detection of powder formation in SiH4/H2 glow discharges

    NASA Astrophysics Data System (ADS)

    Alexiou, G.; Tsigaras, G.; Amanatides, E.; Mataras, D.

    2016-03-01

    Time-resolved self-bias voltage measurements and spatiotemporal resolved optical emission spectroscopy were used in order to monitor particle formation and instabilities in the initial stage of 13.56 MHz SiH4/H2. The effect of total gas pressure on the particles formation and the time required for the plasma to reach steady state was investigated. Both techniques were very sensitive in monitoring the nucleation and coagulation phase of particles formation. The characteristic times required for reaching steady state were similar for both techniques indicating that electrical properties and chemical kinetics are affected in a similar way from particle formation. The increase of pressure resulted in a significant shortening of the instability period and this can be a significant advantage in the deposition of device grade silicon thin films.

  20. Characterization of N-doped multilayer graphene grown on 4H-SiC (0001)

    NASA Astrophysics Data System (ADS)

    Arezki, Hakim; Ho, Kuan-I.; Jaffré, Alexandre; Alamarguy, David; Alvarez, José; Kleider, Jean-Paul; Lai, Chao-Sung; Boutchich, Mohamed

    2015-02-01

    Large-area graphene film doped with hetero-atoms is of great interest for a wide spectrum of nanoelectronics applications, such as field effect devices, super capacitors, fuel cells among many others. Here, we report the structural and electronic properties of nitrogen doped multilayer graphene on 4H-SiC (0001). The incorporation of nitrogen during the growth causes an increase in the D band on the Raman signature indicating that the nitrogen is creating defects. The analysis of micro-Raman mapping of G, D, 2D bands shows a predominantly trilayer graphene with a D band inherent to doping and inhomogeneous dopant distribution at the step edges. Ultraviolet photoelectron spectroscopy (UPS) indicates an n type work function (WF) of 4.1 eV. In addition, a top gate FET device was fabricated showing n-type I-V characteristic after the desorption of oxygen with high electron and holes mobilities.

  1. Accelerated Clean-up of the United States Department of Energy, Mound Nuclear Weapons Facility in Miamisburg, Ohio

    SciTech Connect

    Lehew, J.G.; Bradford, J.D.; Cabbil, C.C.

    2006-07-01

    CH2M HILL is executing a performance-based contract with the United States Department of Energy to accelerate the safe closure of the nuclear facilities at the former Mound plant in Miamisburg, Ohio. The contract started in January 2003 with a target completion date of March 31, 2006. Our accelerated baseline targets completion of the project 2 years ahead of the previous baseline schedule, by spring 2006, and for $200 million less than previous estimates. This unique decommissioning and remediation project is located within the City of Miamisburg proper and is designed for transfer of the property to the Miamisburg Mound Community Improvement Corporation for industrial reuse. The project is being performed with the Miamisburg Mound Community Improvement Corporation and their tenants co-located on the site creating significant logistical, safety and stakeholder challenges. The project is also being performed in conjunction with the United States Department of Energy, United States Environmental Protection Agency, and the Ohio Environmental Protection Agency under the Mound 2000 regulatory cleanup process. The project is currently over 95% complete. To achieve cleanup and closure of the Mound site, CH2M HILL's scope includes: - Demolition of 64 nuclear, radiological and commercial facilities - Preparation for Transfer of 9 facilities (including a Category 2 nuclear facility) to the Miamisburg Mound Community Improvement Corporation for industrial reuse - Removal of all above ground utility structures and components, and preparation for transfer of 9 utility systems to Miamisburg Mound Community Improvement Corporation - Investigation, remediation, closure, and documentation of all known Potential Release Sites contaminated with radiological and chemical contamination (73 identified in original contract) - Storage, characterization, processing, packaging and shipment of all waste and excess nuclear materials - Preparation for Transfer of the 306 acre site to the

  2. Charcot-Marie-Tooth Disease Type 4H Resulting from Compound Heterozygous Mutations in FGD4 from Nonconsanguineous Korean Families.

    PubMed

    Hyun, Young Se; Lee, Jinho; Kim, Hye Jin; Hong, Young Bin; Koo, Heasoo; Smith, Alec S T; Kim, Deok-Ho; Choi, Byung-Ok; Chung, Ki Wha

    2015-11-01

    Charcot-Marie-Tooth disease type 4H (CMT4H) is an autosomal recessive demyelinating subtype of peripheral enuropathies caused by mutations in the FGD4 gene. Most CMT4H patients are in consanguineous Mediterranean families characterized by early onset and slow progression. We identified two CMT4H patients from a Korean CMT cohort, and performed a detailed genetic and clinical analysis in both cases. Both patients from nonconsanguineous families showed characteristic clinical manifestations of CMT4H including early onset, scoliosis, areflexia, and slow disease progression. Exome sequencing revealed novel compound heterozygous mutations in FGD4 as the underlying cause in both families (p.Arg468Gln and c.1512-2A>C in FC73, p.Met345Thr and c.2043+1G>A (p.Trp663Trpfs*30) in FC646). The missense mutations were located in highly conserved RhoGEF and PH domains which were predicted to be pathogenic in nature by in silico modeling. The CMT4H occurrence frequency was calculated to 0.7% in the Korean demyelinating CMT patients. This study is the first report of CMT4H in Korea. FGD4 assay could be considered as a means of molecular diagnosis for sporadic cases of demyelinating CMT with slow progression.

  3. Measurement of Optical, Mechanical and Transport properties of the hexagonal closed packed 4H polytype of metallic silver

    NASA Astrophysics Data System (ADS)

    Chakraborty, Indrani; Shirodkar, Sharmila N.; Gohil, Smita; Waghmare, Umesh; Ayyub, Pushan

    2013-03-01

    Optical, mechanical and transport property measurements were done on the hexagonal closed packed (hcp) 4H polytype of Ag with stacking sequence ABCBABCB.. grown as bulk films on Al2O3 substrates. Diffused reflectance measurements done on the 4H films showed a general loss of reflectivity amounting to a decrease of 35% as compared to normal fcc (3C) Ag near 500 nm with a blueshift of 5nm in the bulk plasmon frequency, possibly due to the modified electronic structure of the hcp form. Raman spectroscopic measurements showed the appearance of a peak at 64.3 cm-1 at 4K which underwent ``Mode softening,'' that is shifted to lower wave numbers with increase of temperature and disappeared above 350K. Low temperature transport measurements done on 4H films gave the in-plane resistivity value to be 39 times higher than that of a similarly synthesized fcc Ag film at 295 K. Vicker's microhardness measurements done on the 4H films showed that the 4H samples to be almost 5 times harder than the 3C Ag. Density functional theory simulations were done to obtain the phonon dispersion, band structure and nature of Fermi surface for the 4H Ag which corroborated with the experimental observations. The 4H form appears to be a much less metallic, darker and harder form of Ag.

  4. Elastic platonic shells.

    PubMed

    Yong, Ee Hou; Nelson, David R; Mahadevan, L

    2013-10-25

    On microscopic scales, the crystallinity of flexible tethered or cross-linked membranes determines their mechanical response. We show that by controlling the type, number, and distribution of defects on a spherical elastic shell, it is possible to direct the morphology of these structures. Our numerical simulations show that by deflating a crystalline shell with defects, we can create elastic shell analogs of the classical platonic solids. These morphologies arise via a sharp buckling transition from the sphere which is strongly hysteretic in loading or unloading. We construct a minimal Landau theory for the transition using quadratic and cubic invariants of the spherical harmonic modes. Our approach suggests methods to engineer shape into soft spherical shells using a frozen defect topology.

  5. Hollow spherical shell manufacture

    DOEpatents

    O'Holleran, T.P.

    1991-11-26

    A process is disclosed for making a hollow spherical shell of silicate glass composition in which an aqueous suspension of silicate glass particles and an immiscible liquid blowing agent is placed within the hollow spherical cavity of a porous mold. The mold is spun to reduce effective gravity to zero and to center the blowing agent, while being heated so as to vaporize the immiscible liquid and urge the water carrier of the aqueous suspension to migrate into the body of the mold, leaving a green shell compact deposited around the mold cavity. The green shell compact is then removed from the cavity, and is sintered for a time and a temperature sufficient to form a silicate glass shell of substantially homogeneous composition and uniform geometry. 3 figures.

  6. Hollow spherical shell manufacture

    DOEpatents

    O'Holleran, Thomas P.

    1991-01-01

    A process for making a hollow spherical shell of silicate glass composition in which an aqueous suspension of silicate glass particles and an immiscible liquid blowing agent is placed within the hollow spherical cavity of a porous mold. The mold is spun to reduce effective gravity to zero and to center the blowing agent, while being heated so as to vaporize the immiscible liquid and urge the water carrier of the aqueous suspension to migrate into the body of the mold, leaving a green shell compact deposited around the mold cavity. The green shell compact is then removed from the cavity, and is sintered for a time and a temperature sufficient to form a silicate glass shell of substantially homogeneous composition and uniform geometry.

  7. C-Shell Cookbook

    NASA Astrophysics Data System (ADS)

    Currie, Malcolm J.

    This cookbook describes the fundamentals of writing scripts using the UNIX C shell. It shows how to combine Starlink and private applications with shell commands and constructs to create powerful and time-saving tools for performing repetitive jobs, creating data-processing pipelines, and encapsulating useful recipes. The cookbook aims to give practical and reassuring examples to at least get you started without having to consult a UNIX manual. However, it does not offer a comprehensive description of C-shell syntax to prevent you from being overwhelmed or intimidated. The topics covered are: how to run a script, defining shell variables, prompting, arithmetic and string processing, passing information between Starlink applications, obtaining dataset attributes and FITS header information, processing multiple files and filename modification, command-line arguments and options, and loops. There is also a glossary.

  8. Clinical spectrum of 4H leukodystrophy caused by POLR3A and POLR3B mutations

    PubMed Central

    Vanderver, Adeline; van Spaendonk, Rosalina M.L.; Schiffmann, Raphael; Brais, Bernard; Bugiani, Marianna; Sistermans, Erik; Catsman-Berrevoets, Coriene; Kros, Johan M.; Pinto, Pedro Soares; Pohl, Daniela; Tirupathi, Sandya; Strømme, Petter; de Grauw, Ton; Fribourg, Sébastien; Demos, Michelle; Pizzino, Amy; Naidu, Sakkubai; Guerrero, Kether; van der Knaap, Marjo S.; Bernard, Geneviève

    2014-01-01

    Objective: To study the clinical and radiologic spectrum and genotype–phenotype correlation of 4H (hypomyelination, hypodontia, hypogonadotropic hypogonadism) leukodystrophy caused by mutations in POLR3A or POLR3B. Methods: We performed a multinational cross-sectional observational study of the clinical, radiologic, and molecular characteristics of 105 mutation-proven cases. Results: The majority of patients presented before 6 years with gross motor delay or regression. Ten percent had an onset beyond 10 years. The disease course was milder in patients with POLR3B than in patients with POLR3A mutations. Other than the typical neurologic, dental, and endocrine features, myopia was seen in almost all and short stature in 50%. Dental and hormonal findings were not invariably present. Mutations in POLR3A and POLR3B were distributed throughout the genes. Except for French Canadian patients, patients from European backgrounds were more likely to have POLR3B mutations than other populations. Most patients carried the common c.1568T>A POLR3B mutation on one allele, homozygosity for which causes a mild phenotype. Systematic MRI review revealed that the combination of hypomyelination with relative T2 hypointensity of the ventrolateral thalamus, optic radiation, globus pallidus, and dentate nucleus, cerebellar atrophy, and thinning of the corpus callosum suggests the diagnosis. Conclusions: 4H is a well-recognizable clinical entity if all features are present. Mutations in POLR3A are associated with a more severe clinical course. MRI characteristics are helpful in addressing the diagnosis, especially if patients lack the cardinal non-neurologic features. PMID:25339210

  9. Development of 4H-pyridopyrimidines: a class of selective bacterial protein synthesis inhibitors

    PubMed Central

    2012-01-01

    Background We have identified a series of compounds that inhibit protein synthesis in bacteria. Initial IC50's in aminoacylation/translation (A/T) assays ranged from 3 to14 μM. This series of compounds are variations on a 5,6,7,8-tetrahydropyrido[4,3-d]pyrimidin-4-ol scaffold (e.g., 4H-pyridopyrimidine). Methods Greater than 80 analogs were prepared to investigate the structure-activity relationship (SAR). Structural modifications included changes in the central ring and substituent modifications in its periphery focusing on the 2- and 6-positions. An A/T system was used to determine IC50 values for activity of the analogs in biochemical assays. Minimum inhibitory concentrations (MIC) were determined for each analog against cultures of Enterococcus faecalis, Moraxella catarrhalis, Haemophilus influenzae, Streptococcus pneumoniae, Staphylococcus aureus, Escherichia coli tolC mutants and E. coli modified with PMBN. Results Modifications to the 2-(pyridin-2-yl) ring resulted in complete inactivation of the compounds. However, certain modifications at the 6-position resulted in increased antimicrobial potency. The optimized compounds inhibited the growth of E. faecalis, M. catarrhalis, H. influenzae, S. pneumoniae, S. aureus, E. coli tolC, mutants and E. coli modified with PMBN with MIC values of 4, ≤ 0.12, 1, 2, 4, 1, 1 μg/ml, respectively. IC50 values in biochemical assay were reduced to mid-nanomolar range. Conclusion 4H-pyridopyrimidine analogs demonstrate broad-spectrum inhibition of bacterial growth and modification of the compounds establishes SAR. PMID:22373064

  10. Cryogenesis study of a pingo-like mound in the Akkol valley of the Russian Altai Mountains

    NASA Astrophysics Data System (ADS)

    Iwahana, G.; Fukui, K.; Fujii, Y.; Ostanin, O.; Mikhailov, N.

    2008-12-01

    Vertical outcrop of a pingo-like mound found in the Akkol valley of the Russian Altai Mountains is described. Several pingo-like mounds were found on the valley floor at about 2300 m ASL. They are 5 - 10 m high and up to 50 m in diameter. Part of a 5 m mound had collapsed into adjacent pond with continuous water supply from streams on the mountain ridge nearby and top 4 m section had been revealed. Highly complex combinations of segregated ice lenses were observed in the outcrop. Ice veins, which are consisted by a number of thick ice lenses, develop radially from the core of the mound. The areas in-between the ice veins had fine parallel lenticular cryostructure. Surface soil layer (about one meter) and patchy soil parts between ice lenses were made of fine till of lacustrine sediments. delta O18 values of water from these ice lenses range from -15 to -18. Spatial distribution of the isotope values was well correlated with the spatial pattern of the ice lenses"f distribution. In addition to segregation of ice lenses perpendicular to the temperature gradient, contribution of relatively rapid formation of ice in radial direction from the core of the mound can be large in this three dimensional frost heave phenomenon.

  11. Ft-Ir Spectroscopic Analysis of Potsherds Excavated from the First Settlement Layer of Kuriki Mound, Turkey

    NASA Astrophysics Data System (ADS)

    Bayazit, Murat; Isik, Iskender; Cereci, Sedat; Issi, Ali; Genc, Elif

    The region covering Southeastern Anatolia takes place in upper Mesopotamia, so it has numerous cultural heritages due to its witness to various social movements of different civilizations in ancient times. Kuruki Mound is located on the junction point of Tigris River and Batman Creek, near Oymatas village which is almost 15 km to Batman, Turkey. The mound is dated back to Late Chalcolithic. Archaeological excavations are carried out on two hills named as “Kuriki Mound-1” and “Kuriki Mound-2” in which 4-layer and 2-layer settlements have been revealed, respectively. This region will be left under the water by the reservoir lake of Ilısu Dam when its construction is completed. Thus, characterization of ancient materials such as potsherds, metals and skeleton ruins should be rapidly done. In this study, 12 potsherds excavated from Layer-1 (the first settlement layer after the surface) in Kuriki Mound-2 were investigated by FT-IR spectrometry. Energy dispersive X-ray fluorescence (EDXRF) and X-ray diffraction (XRD) analyses were used as complementary techniques in order to expose chemical and mineralogical/phase contents, respectively. Obtained results showed that the potteries have been produced with calcareous clays and they include moderate amounts of MgO, K2O, Na2O and Fe2O3 in this context. Additionally, high temperature phases have also been detected with XRD analyses in some samples.

  12. Technical Review Report for the Mound 1KW Package Safety Analysis Report for Packaging Addendum No. 1, through Revision b

    SciTech Connect

    DiSabatino, A; West, M; Hafner, R; Russell, E

    2007-10-04

    This Technical Review Report (TRR) documents the review, performed by the Lawrence Livermore National Laboratory (LLNL) staff, at the request of the U.S. Department of Energy (DOE), on the 'Mound 1KW Package Safety Analysis Report for Packaging, Addendum No. 1, Revision b', dated May 2007 (Addendum 1). The Mound 1KW Package is certified by DOE Certificate of Compliance (CoC) number USA/9516/B(U)F-85 for the transportation of Type B quantities of plutonium heat source material. The safety analysis of the package is documented in the 'Safety Analysis Report for Packaging (SARP) for the Mound 1KW Package' (i.e., the Mound 1KW SARP, or the SARP). Addendum 1 incorporates a new fueled capsule assembly payload. The following changes have been made to add this payload: (1) The primary containment vessel (PCV) will be of the same design, but will increase in height to 11.16 in.; (2) A new graphite support block will be added to support up to three fueled capsule assemblies per package; (3) The cutting groove height on the secondary containment vessel (SCV) will be heightened to accommodate the taller PCV; and (4) A 3.38 in. high graphite filler block will be placed on top of the PCV. All other packaging features, as described in the Mound 1KW SARP [3], remain unchanged. This report documents the LLNL review of Addendum 1[1]. The specific review for each SARP Chapter is documented herein.

  13. Interpretation of Late Cretaceous Volcanic Mounds and Surrounding Gulfian Series Formations Using 3D Seismic Data in Zavala County, Texas

    NASA Astrophysics Data System (ADS)

    Bennett, Laura Claire

    The Late Cretaceous Gulfian series is a prominent and important series across the State of Texas that has been extensively studied since the nineteenth century. It is composed of series of southeast-dipping shelf carbonates and clastics deposited on the northwest margin of the Gulf of Mexico Basin. In south Texas, the Gulfian series was deposited in the Rio Grande Embayment and Maverick Basin and is comprised of the Eagle Ford Group, Austin Group, Anacacho Limestone, San Miguel Formation, Olmos Formation, and Escondido Formation that crop out and continue basinward in the subsurface. Late Cretaceous volcanism formed volcanic mounds composed of altered palagonite tuff that are clustered into two fields, including the Uvalde Field centered in Zavala County. Using the Pedernales 3D seismic survey, located in east-central Zavala County, several volcanic mounds were identified and mapped without the use of well log data by identifying structures and characteristics associated with the volcanic mounds. Isolating these mounds through mapping enabled the mapping of the tops surrounding Gulfian formations, Lower Eagle Ford, Upper Eagle Ford, Austin, Anacacho, and San Miguel, for which time-structure, amplitude, similarity/coherency attribute, and isochron maps were generated. By using 3D seismic data, the volcanic mounds and their relation to surrounding rocks can be better interpreted.

  14. Connecting Kids To The Universe: Partnering With 4-H Youth Development To Pilot 'Afterschool Universe' In New York

    NASA Astrophysics Data System (ADS)

    Schaff, Nancy

    2008-05-01

    4-H Youth Development - as the youth program of the Cooperative Extension system associated with the land grant university in every state - is an ideal partner for statewide dissemination of EPO programs. With funding from a Chandra Cycle 9 EPO grant we are piloting `Afterschool Universe’ in five urban locations in New York State. `Afterschool Universe’ is an education/outreach effort sponsored by NASA's Beyond Einstein program and was developed in partnership with the Imagine the Universe EPO program. The program is targeted at middle school students in out-of-school-time settings and explores basic astronomy concepts focused on the Universe beyond the solar system. Consisting of 12 sessions of engaging hands-on activities, the flexibly structured program can be used in a variety of settings, including astronomy days, youth groups, summer camps, and afterschool programs. Partnering with 4-H Youth Development helps us reach large numbers of underserved and underrepresented minority youth and girls in widely dispersed areas of New York and fits ideally with the current national 4-H SET (science, engineering, and technology) initiative and emphasis on 4-H afterschool programming. The pilot program provides teaching kits and workshops for program leaders. Our 4-H county partners recruit afterschool program staff, science center staff, 4-H volunteers, 4-H teens, and other youth group leaders as workshop participants. The 4-H program will house and loan the kit to trained leaders. By providing kits and training in 2008, we are gearing up for International Year of Astronomy programs in 2009 in out-of-school settings. Based on pilot results, we will seek additional funding to expand the program. The poster will discuss kit development, 4-H partnership, workshops, participating organizations, target audiences, successes, and challenges.

  15. Shells and Patterns

    ERIC Educational Resources Information Center

    Sutley, Jane

    2009-01-01

    "Shells and Patterns" was a project the author felt would easily put smiles on the faces of her fifth-graders, and teach them about unity and the use of watercolor pencils as well. It was thrilling to see the excitement in her students as they made their line drawings of shells come to life. For the most part, they quickly got the hang of…

  16. Double shell liner implosions

    SciTech Connect

    Sorokin, S. A.; Chaikovsky, S. A.

    1997-05-05

    Experiments on the double shell liner (DSL) implosions with and without an initial axial magnetic were performed on the SNOP-3 pulse generator (1.1 MA, 100 ns). In implosions of a DSL without an initial axial magnetic field, high radial compressions of the inner shell were observed, as in previous experiments with an initial axial magnetic field. Possible mechanisms for the formation of the initial azimuthal magnetic field are discussed.

  17. Discovery of hydrothermally active and extinct talc mounds on the Mid-Cayman Rise

    NASA Astrophysics Data System (ADS)

    Hodgkinson, M.; Murton, B. J.; Roberts, S.

    2013-12-01

    Since 1977, hydrothermal vents have been the subject of intense scientific interest due to their role in cooling the oceanic crust and global geochemical cycles. Until now, two types of hydrothermal system have been identified: one, driven by magmatic heat extruding ';black smoker' fluids; and another, involving serpentinisation of ultramafic rocks and the precipitation of carbonate/brucite chimneys. Here, we present details of a new, off-axis type of hydrothermal system consisting of mounds of predominately botryoidal talc (a magnesium-silicate) with accessory silica and copper sulphides, and chimneys exhaling fluids of moderate temperature and pH. Discovered on the Mid-Cayman Rise (MCR) in 2010, the Von Damm Vent Field (VDVF) features a NNW-ESE-trending line of four overlapping cones, the largest of which is 75 m high by 150 m in diameter. The VDVF is hosted in the gabbroic footwall of the Mount Dent Oceanic Core Complex (MDOCC), which includes serpentinised peridotite at depth. The largest cone vents clear fluids from two main orifices at its summit, with primary temperatures of 215°C. Elsewhere, both focussed and diffuse flow areas emit fluids with temperatures of up to 150°C. The surrounding ~1 m thick pelagic sediment contains abundant pockmarks that emit methane-rich fluids at temperatures of less than 10°C. During the return to the MCR in early 2013, several other talc mounds were discovered within a kilometre of the active VDVF. These inactive mounds also comprise an assemblage of botryoidal talc, silica, disseminated sulphides (including chalcopyrite) and sulphates. One of these mounds (Mystic Mount) is double the volume of the active VDVF. The unique dominance of talc as the major mineral forming the hydrothermal structures indicates unusual vent fluid compositions that are able to carry both copper (at high-temperatures) and precipitate magnesium silicate. Thermodynamic modelling indicates that talc precipitates on mixing a moderately acidic, silica

  18. Synthesis of N-Aryl-3,5-dichloro-4H-1,2,6-thiadiazin-4-imines from 3,4,4,5-Tetrachloro-4H-1,2,6-thiadiazine.

    PubMed

    Kalogirou, Andreas S; Manoli, Maria; Koutentis, Panayiotis A

    2015-08-21

    Condensation of 3,4,4,5-tetrachloro-4H-1,2,6-thiadiazine with a range of anilines gave 22 N-aryl-3,5-dichloro-4H-1,2,6-thiadiazin-4-imines in 43-96% yields. The scope and limitations of this condensation are briefly investigated. Furthermore, mono- and bis-substitution of the C-3 and C-5 chlorines of 3,5-dichloro-N-phenyl-4H-1,2,6-thiadiazin-4-imine by amine and alkoxide nucleophiles is explored. Finally, Stille coupling chemistry is used to prepare several N-phenyl-3,5-diaryl-4H-1,2,6-thiadiazin-4-imines. PMID:26261875

  19. Early Carboniferous (Tournasian-early Visean) global paleogeography, Paleostorm tracts, and the distribution of Waulsortian and Waulsortian-like carbonate mud mounds

    SciTech Connect

    King, D.T. Jr. )

    1990-05-01

    Tournasian-early Visean mud mounds (i.e., Waulsortian and Waulsortian-like mounds) are unlike other carbonate buildups in the stratigraphic record because they lack an identifiable frame-building organism. Waulsortian mounds are comprised mainly of carbonate mud; Waulsortian-like mounds are mud-rich and contain a significant percent of skeletal grains, especially crinoids and bryozoa. This study has revealed that all of the reported Waulsortian and Waulsortian-like mounds developed in low paleolatitudes either on the southern shelf margin of the Laurussian paleocontinent or in the Laurussian interior seaway. Waulsortian and Waulsortian-like mounds are specifically not present in low-latitude regions of other paleocontinents. As Tournasian-early Visean carbonate deposition was widespread in the range of 30{degree}N to 10{degree}S, the very restricted paleogeographic distribution of Waulsortian and Waulsortian-like mound locations suggests a mechanism or set of conditions that effectively limited the distribution of mud mounds. Considering the Tournasian-early Visean distribution of paleocontinents and the principles that govern the movement of modern hurricanes, tropical storms, and winter storms, the tracts of hurricanes, tropical storms, and winter storms probably crossed all main submerged paleocontinental areas except the southern Laurussian shelf margin and the Laurussian interior seaway, the two areas where mud mounds developed. The lack of storm energy in these two large areas of Laurussia provided long-term stability and thus enhanced the growth prospects of the frame-deficient Waulsortian and Waulsortian-like mud mounds. Lack of extensive periodic wave reworking and other storm-induced devastation helps to account for enigmatic features such as general mound symmetry, great size, high depositional relief (as much as 220 m), and side steepness (as steep as 50{degree}).

  20. Mound Spring Complexes in Central Australia: An Analog for Martian Groundwater Fed Outflow Channels?

    NASA Technical Reports Server (NTRS)

    Clarke, J. D. A.; Stoker, C.

    2003-01-01

    The arid inland of Australia contains a diversity of landscapes and landscape processes, often of great antiquity, extending back to the Mesozoic and Paleozoic. The potential of this landscape as a source of Mars analogs has, however, been little explored. The few examples studied so far include radiation-tolerant microbes in thermal springs and hematite-silica hydrothermal alteration near Arkaroola in the Finders Ranges, and aeolian landforms at Gurra Gurra water hole the north east of Arkaroola. Further Australian Mars analog studies were provided by the studies of Bourke and Zimbelman of the paleoflood record of the Todd and Hale Rivers in central Australia. To facilitate study of such analogues, Mars Society Australia has embarked on a project to construct a Mars Analog Research Station near Arkaroola. The international scientific community will soon have the opportunity to participate in Mars analog studies in central Australia utilizing this facility. An area of considerable Mars analog potential is the mound spring complexes that occur at the margins of the Great Artesian Basin (GAB) which underlies 22% of the Australian continent and covers 1.7 million km2. The mound springs are formed when ground water flows to a topographic low, and subsurface strata dips up causing a hydrological head at the surface. Minerals precipitated at the spring discharge zone form low mesas or "mounds", the height of which are controlled by the hydrological head. This paper describes the Dalhousie Mound Spring Complex (DMC) in the northern part of South Australia (Figure 1), and its potential as a Mars analog. Hydrogeology: The DMC consists of a cluster of more than 60 active springs formed by natural discharge from the GAB). Total measured discharge from the GAB is 1.74 GL per day, estimated unfocussed natural leakage through the aquaclude is thought be approximately equal to this figure. Some 54 ML per day are currently discharged by the DMC, 3% of the measured total. The