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Sample records for bearing foraminifera amphistegina

  1. Combined effects of sea water acidification and copper exposure on the symbiont-bearing foraminifer Amphistegina gibbosa

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    Marques, Joseane Aparecida; de Barros Marangoni, Laura Fernandes; Bianchini, Adalto

    2017-06-01

    Coral reefs are threatened by global and local stressors such as ocean acidification and trace metal contamination. Reliable early warning monitoring tools are needed to assess and monitor coral reef health. Symbiont-bearing foraminifers ( Amphistegina gibbosa) were kept under ambient conditions (no sea water acidification and no copper addition) or exposed to combinations of different levels of sea water pH (8.1, 7.8, 7.5 and 7.2) and environmentally relevant concentrations of dissolved copper (measured: 1.0, 1.6, 2.3 and 3.2 µg L-1) in a mesocosm system. After 10- and 25-d exposure, foraminifers were analyzed for holobiont Ca2+-ATPase activity, bleaching, growth and mortality. Enzyme activity was inhibited in foraminifers exposed to pH 7.2 and 3.2 µg L-1 Cu for 25 d. Bleaching frequency was also higher at pH 7.2 combined with copper addition. There was no significant effect of sea water acidification and copper addition on mortality. However, test size was smaller in foraminifers exposed to copper, with a positive interactive effect of sea water acidification. These findings can be explained by the higher availability of free copper ions at lower water pH. This condition would increase Cu competition with Ca2+ for the binding sites on the organism, thus inhibiting Ca2+-ATPase activity and affecting the organism's overall fitness. Findings reported here suggest that key processes in A. gibbosa, such as calcification and photosynthesis, are affected by the combined effect of global (sea water acidification) and local (copper contamination) stressors. Considering the experimental conditions employed (mesocosm system, possible ocean acidification scenarios, low copper concentrations, biomarkers of ecological relevance and chronic exposure), our findings support the use of foraminifera and biomarkers analyzed in the present study as reliable tools to detect and monitor the ecological impacts of multiple stressors in coral reef environments.

  2. The presence of the Indo-Pacific symbiont-bearing foraminifer Amphistegina lobifera in Greek coastal ecosystems (Aegean Sea, Eastern Mediterranean

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    M.V. TRIANTAPHYLLOU

    2009-12-01

    Full Text Available During the last decades, hundreds of species of Indo-Pacific origin from the Red Sea have traversed the Suez Canal and settled in the Eastern Mediterranean. Nowadays, Amphistegina lobifera Larsen, is known to be a successful immigrant that is widely distributed in the coastal ecosystems of the Eastern Mediterranean Sea. Amphistegina is the most common epiphytic, symbiont- bearing large foraminifer. In this study we provide additional data on the presence of this species in the coastal ecosystems of Aegean Sea, Greece. The high relative abundance of A. lobifera is the result of very successful adaptation of this species to local conditions and suggests that it has become a significant part of the epiphytic foraminiferal fauna.

  3. Molecular evidence for Lessepsian invasion of soritids (larger symbiont bearing benthic foraminifera.

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    Gily Merkado

    Full Text Available The Mediterranean Sea is considered as one of the hotspots of marine bioinvasions, largely due to the influx of tropical species migrating through the Suez Canal, so-called Lessepsian migrants. Several cases of Lessepsian migration have been documented recently, however, little is known about the ecological characteristics of the migrating species and their aptitude to colonize the new areas. This study focused on Red Sea soritids, larger symbiont-bearing benthic foraminifera (LBF that are indicative of tropical and subtropical environments and were recently found in the Israeli coast of the Eastern Mediterranean. We combined molecular phylogenetic analyses of soritids and their algal symbionts as well as network analysis of Sorites orbiculus Forskål to compare populations from the Gulf of Elat (northern Red Sea and from a known hotspot in Shikmona (northern Israel that consists of a single population of S. orbiculus. Our phylogenetic analyses show that all specimens found in Shikmona are genetically identical to a population of S. orbiculus living on a similar shallow water pebbles habitat in the Gulf of Elat. Our analyses also show that the symbionts found in Shikmona and Elat soritids belong to the Symbiodinium clade F5, which is common in the Red Sea and also present in the Indian Ocean and Caribbean Sea. Our study therefore provides the first genetic and ecological evidences that indicate that modern population of soritids found on the Mediterranean coast of Israel is probably Lessepsian, and is less likely the descendant of a native ancient Mediterranean species.

  4. Additive pressures of elevated sea surface temperatures and herbicides on symbiont-bearing foraminifera.

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    Joost W van Dam

    Full Text Available Elevated ocean temperatures and agrochemical pollution individually threaten inshore coral reefs, but these pressures are likely to occur simultaneously. Experiments were conducted to evaluate the combined effects of elevated temperature and the photosystem II (PSII inhibiting herbicide diuron on several types of symbiotic algae (diatom, dinoflagellate or rhodophyte of benthic foraminifera in hospite. Diuron was shown to evoke a direct effect on photosynthetic efficiency (reduced effective PSII quantum yield ΔF/F'(m, while elevated temperatures (>30 °C, only 2 °C above current average summer temperatures were observed to impact photosynthesis more indirectly by causing reductions in maximum PSII quantum yield (F(v/F(m, interpreted as photodamage. Additionally, elevated temperatures were shown to cause bleaching through loss of chlorophyll a in foraminifera hosting either diatoms or dinoflagellates. A significant linear correlation was found between reduced F(v/F(m and loss of chlorophyll a. In most cases, symbionts within foraminifera proved more sensitive to thermal stress in the presence of diuron (≥ 1 µg L(-1. The mixture toxicity model of Independent Action (IA described the combined effects of temperature and diuron on the photosystem of species hosting diatoms or dinoflagellates convincingly and in agreement with probabilistic statistics, so a response additive joint action can be assumed. We thus demonstrate that improving water quality can improve resilience of symbiotic phototrophs to projected increases in ocean temperatures. As IA described the observed combined effects from elevated temperature and diuron stress it may therefore be employed for prediction of untested mixtures and for assessing the efficacy of management measures.

  5. Additive pressures of elevated sea surface temperatures and herbicides on symbiont-bearing foraminifera.

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    van Dam, Joost W; Negri, Andrew P; Mueller, Jochen F; Altenburger, Rolf; Uthicke, Sven

    2012-01-01

    Elevated ocean temperatures and agrochemical pollution individually threaten inshore coral reefs, but these pressures are likely to occur simultaneously. Experiments were conducted to evaluate the combined effects of elevated temperature and the photosystem II (PSII) inhibiting herbicide diuron on several types of symbiotic algae (diatom, dinoflagellate or rhodophyte) of benthic foraminifera in hospite. Diuron was shown to evoke a direct effect on photosynthetic efficiency (reduced effective PSII quantum yield ΔF/F'(m)), while elevated temperatures (>30 °C, only 2 °C above current average summer temperatures) were observed to impact photosynthesis more indirectly by causing reductions in maximum PSII quantum yield (F(v)/F(m)), interpreted as photodamage. Additionally, elevated temperatures were shown to cause bleaching through loss of chlorophyll a in foraminifera hosting either diatoms or dinoflagellates. A significant linear correlation was found between reduced F(v)/F(m) and loss of chlorophyll a. In most cases, symbionts within foraminifera proved more sensitive to thermal stress in the presence of diuron (≥ 1 µg L(-1)). The mixture toxicity model of Independent Action (IA) described the combined effects of temperature and diuron on the photosystem of species hosting diatoms or dinoflagellates convincingly and in agreement with probabilistic statistics, so a response additive joint action can be assumed. We thus demonstrate that improving water quality can improve resilience of symbiotic phototrophs to projected increases in ocean temperatures. As IA described the observed combined effects from elevated temperature and diuron stress it may therefore be employed for prediction of untested mixtures and for assessing the efficacy of management measures.

  6. Recent Invasion of the Symbiont-Bearing Foraminifera Pararotalia into the Eastern Mediterranean Facilitated by the Ongoing Warming Trend.

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    Schmidt, Christiane; Morard, Raphael; Almogi-Labin, Ahuva; Weinmann, Anna E; Titelboim, Danna; Abramovich, Sigal; Kucera, Michal

    2015-01-01

    The eastern Mediterranean is a hotspot of biological invasions. Numerous species of Indo-pacific origin have colonized the Mediterranean in recent times, including tropical symbiont-bearing foraminifera. Among these is the species Pararotalia calcariformata. Unlike other invasive foraminifera, this species was discovered only two decades ago and is restricted to the eastern Mediterranean coast. Combining ecological, genetic and physiological observations, we attempt to explain the recent invasion of this species in the Mediterranean Sea. Using morphological and genetic data, we confirm the species attribution to P. calcariformata McCulloch 1977 and identify its symbionts as a consortium of diatom species dominated by Minutocellus polymorphus. We document photosynthetic activity of its endosymbionts using Pulse Amplitude Modulated Fluorometry and test the effects of elevated temperatures on growth rates of asexual offspring. The culturing of asexual offspring for 120 days shows a 30-day period of rapid growth followed by a period of slower growth. A subsequent 48-day temperature sensitivity experiment indicates a similar developmental pathway and high growth rate at 28°C, whereas an almost complete inhibition of growth was observed at 20°C and 35°C. This indicates that the offspring of this species may have lower tolerance to cold temperatures than what would be expected for species native to the Mediterranean. We expand this hypothesis by applying a Species Distribution Model (SDM) based on modern occurrences in the Mediterranean using three environmental variables: irradiance, turbidity and yearly minimum temperature. The model reproduces the observed restricted distribution and indicates that the range of the species will drastically expand westwards under future global change scenarios. We conclude that P. calcariformata established a population in the Levant because of the recent warming in the region. In line with observations from other groups of organisms

  7. Recent Invasion of the Symbiont-Bearing Foraminifera Pararotalia into the Eastern Mediterranean Facilitated by the Ongoing Warming Trend.

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    Christiane Schmidt

    Full Text Available The eastern Mediterranean is a hotspot of biological invasions. Numerous species of Indo-pacific origin have colonized the Mediterranean in recent times, including tropical symbiont-bearing foraminifera. Among these is the species Pararotalia calcariformata. Unlike other invasive foraminifera, this species was discovered only two decades ago and is restricted to the eastern Mediterranean coast. Combining ecological, genetic and physiological observations, we attempt to explain the recent invasion of this species in the Mediterranean Sea. Using morphological and genetic data, we confirm the species attribution to P. calcariformata McCulloch 1977 and identify its symbionts as a consortium of diatom species dominated by Minutocellus polymorphus. We document photosynthetic activity of its endosymbionts using Pulse Amplitude Modulated Fluorometry and test the effects of elevated temperatures on growth rates of asexual offspring. The culturing of asexual offspring for 120 days shows a 30-day period of rapid growth followed by a period of slower growth. A subsequent 48-day temperature sensitivity experiment indicates a similar developmental pathway and high growth rate at 28°C, whereas an almost complete inhibition of growth was observed at 20°C and 35°C. This indicates that the offspring of this species may have lower tolerance to cold temperatures than what would be expected for species native to the Mediterranean. We expand this hypothesis by applying a Species Distribution Model (SDM based on modern occurrences in the Mediterranean using three environmental variables: irradiance, turbidity and yearly minimum temperature. The model reproduces the observed restricted distribution and indicates that the range of the species will drastically expand westwards under future global change scenarios. We conclude that P. calcariformata established a population in the Levant because of the recent warming in the region. In line with observations from other

  8. Spatial Patterns in the Distribution, Diversity and Abundance of Benthic Foraminifera around Moorea (Society Archipelago, French Polynesia).

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    Fajemila, Olugbenga T; Langer, Martin R; Lipps, Jere H

    2015-01-01

    Coral reefs are now subject to global threats and influences from numerous anthropogenic sources. Foraminifera, a group of unicellular shelled organisms, are excellent indicators of water quality and reef health. Thus we studied a set of samples taken in 1992 to provide a foraminiferal baseline for future studies of environmental change. Our study provides the first island-wide analysis of shallow benthic foraminifera from around Moorea (Society Archipelago). We analyzed the composition, species richness, patterns of distribution and abundance of unstained foraminiferal assemblages from bays, fringing reefs, nearshore and back- and fore-reef environments. A total of 380 taxa of foraminifera were recorded, a number that almost doubles previous species counts. Spatial patterns of foraminiferal assemblages are characterized by numerical abundances of individual taxa, cluster groups and gradients of species richness, as documented by cluster, Fisher α, ternary plot and Principal Component Analyses (PCA). The inner bay inlets are dominated by stress-tolerant, mostly thin-shelled taxa of Bolivina, Bolivinella, Nonionoides, Elongobula, and Ammonia preferring low-oxygen and/or nutrient-rich habitats influenced by coastal factors such as fresh-water runoff and overhanging mangroves. The larger symbiont-bearing foraminifera (Borelis, Amphistegina, Heterostegina, Peneroplis) generally live in the oligotrophic, well-lit back- and fore-reef environments. Amphisteginids and peneroplids were among the few taxa found in the bay environments, probably due to their preferences for phytal substrates and tolerance to moderate levels of eutrophication. The fringing reef environments along the outer bay are characterized by Borelis schlumbergeri, Heterostegina depressa, Textularia spp. and various miliolids which represent a hotspot of diversity within the complex reef-lagoon system of Moorea. The high foraminiferal Fisher α and species richness diversity in outer bay fringing reefs

  9. Spatial Patterns in the Distribution, Diversity and Abundance of Benthic Foraminifera around Moorea (Society Archipelago, French Polynesia.

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    Olugbenga T Fajemila

    Full Text Available Coral reefs are now subject to global threats and influences from numerous anthropogenic sources. Foraminifera, a group of unicellular shelled organisms, are excellent indicators of water quality and reef health. Thus we studied a set of samples taken in 1992 to provide a foraminiferal baseline for future studies of environmental change. Our study provides the first island-wide analysis of shallow benthic foraminifera from around Moorea (Society Archipelago. We analyzed the composition, species richness, patterns of distribution and abundance of unstained foraminiferal assemblages from bays, fringing reefs, nearshore and back- and fore-reef environments. A total of 380 taxa of foraminifera were recorded, a number that almost doubles previous species counts. Spatial patterns of foraminiferal assemblages are characterized by numerical abundances of individual taxa, cluster groups and gradients of species richness, as documented by cluster, Fisher α, ternary plot and Principal Component Analyses (PCA. The inner bay inlets are dominated by stress-tolerant, mostly thin-shelled taxa of Bolivina, Bolivinella, Nonionoides, Elongobula, and Ammonia preferring low-oxygen and/or nutrient-rich habitats influenced by coastal factors such as fresh-water runoff and overhanging mangroves. The larger symbiont-bearing foraminifera (Borelis, Amphistegina, Heterostegina, Peneroplis generally live in the oligotrophic, well-lit back- and fore-reef environments. Amphisteginids and peneroplids were among the few taxa found in the bay environments, probably due to their preferences for phytal substrates and tolerance to moderate levels of eutrophication. The fringing reef environments along the outer bay are characterized by Borelis schlumbergeri, Heterostegina depressa, Textularia spp. and various miliolids which represent a hotspot of diversity within the complex reef-lagoon system of Moorea. The high foraminiferal Fisher α and species richness diversity in outer bay

  10. Boron incorporation in the foraminifer Amphistegina lessonii under a decoupled carbonate chemistry

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    Kaczmarek, K.; Langer, G.; Nehrke, G.; Horn, I.; Misra, S.; Janse, M.; Bijma, J.

    2015-03-01

    A number of studies have shown that the boron isotopic composition (δ11B) and the B / Ca ratio of biogenic carbonates (mostly foraminifers) can serve as proxies for two parameters of the ocean's carbonate chemistry, rendering it possible to calculate the entire carbonate system. However, the B incorporation mechanism into marine carbonates is still not fully understood and analyses of field samples show species-specific and hydrographic effects on the B proxies complicating their application. Identifying the carbonate system parameter influencing boron incorporation is difficult due to the co-variation of pH, CO32- and B(OH)4-. To shed light on the question which parameter of the carbonate system is related to the boron incorporation, we performed culture experiments with the benthic symbiont-bearing foraminifer Amphistegina lessonii using a decoupled pH-CO32- chemistry. The determination of the δ11B and B / Ca ratios was performed simultaneously by means of a new in situ technique combining optical emission spectroscopy and laser ablation MC-ICP-MS. The boron isotopic composition in the tests gets heavier with increasing pH and B / Ca increases with increasing B(OH)4- / HCO3- of the culture media. The latter indicates that boron uptake of A. lessonii features a competition between B(OH)4- and HCO3-. Furthermore, the simultaneous determination of B / Ca and δ11B on single specimens allows for assessing the relative variability of these parameters. Among different treatments the B / Ca shows an increasing variability with increasing boron concentration in the test whereas the variability in the isotope distribution is constant.

  11. Invertebrate shells (mollusca, foraminifera) as pollution indicators, Red Sea Coast, Egypt

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    Youssef, Mohamed; Madkour, Hashem; Mansour, Abbas; Alharbi, Wedad; El-Taher, Atef

    2017-09-01

    To assess the degree of pollution and its impact on the environment along the Red Sea Coast, the most abundant nine species of recent benthic foraminifera and three species of molluscan shells have been selected for the analysis of Fe, Mn, Zn, Cu, Pb, Ni, Co, and Cd concentrations. The selected foraminiferal species are: Textularia agglutinans, Amphispsorus hemprichii, Sorites marginalis, Peneroplis planatus, Borelis schlumbergeri, Amphistegina lessonii, Ammonia beccarii, Operculina gaimairdi, and Operculinella cumingii. The selected molluscan shells are: Lambis truncata and Strombus tricornis (gastropods) and Tridacana gigas (bivalves). The inorganic material analysis of foraminifera and molluscs from the Quseir and Safaga harbors indicates that foraminifera tests include higher concentrations of heavy metals such as Fe and Mn than molluscan shells. These results are supported by the black tests of porcelaneous foraminifera and reflect iron selectivity. The Cd and Pb concentrations in molluscan shells are high in the El Esh Area because of oil pollution at this site. The Cu, Zn, and Ni concentrations in the studied invertebrates are high at Quseir Harbor and in the El Esh Area because of the strong influence of terrigenous materials that are rich in these metals. The heavy metal contamination is mostly attributed to anthropogenic sources.

  12. 2. Tertiary Foraminifera

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    Umbgrove, J.H.F.

    1931-01-01

    In his review of the palaeozoology of Java, K. Martin could in 1919, record 49 foraminifera from tertiary strata of Java, on the strength of a critical study of the existant literature, and especially on the strength of his own studies and knowledge of the above mentioned fossils (Bibl. 49). In

  13. Variation in sensitivity of large benthic Foraminifera to the combined effects of ocean warming and local impacts.

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    Prazeres, Martina; Roberts, T Edward; Pandolfi, John M

    2017-03-23

    Large benthic foraminifera (LBF) are crucial marine calcifiers in coral reefs, and sensitive to environmental changes. Yet, many species successfully colonise a wide range of habitats including highly fluctuating environments. We tested the combined effects of ocean warming, local impacts and different light levels on populations of the common LBF Amphistegina lobifera collected along a cross-shelf gradient of temperature and nutrients fluctuations. We analysed survivorship, bleaching frequency, chlorophyll a content and fecundity. Elevated temperature and nitrate significantly reduced survivorship and fecundity of A. lobifera across populations studied. This pattern was exacerbated when combined with below optimum light levels. Inshore populations showed a consistent resistance to increased temperature and nitrate levels, but all populations studied were significantly affected by light reduction. These findings demonstrated the capacity of some populations of LBF to acclimate to local conditions; nonetheless improvements in local water quality can ultimately ameliorate effects of climate change in local LBF populations.

  14. Impact of seawater [Ca2+] on the calcification and calcite Mg / Ca of Amphistegina lessonii

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    Mewes, A.; Langer, G.; Thoms, S.; Nehrke, G.; Reichart, G. J.; de Nooijer, L. J.; Bijma, J.

    2015-01-01

    Mg / Ca ratios in foraminiferal tests are routinely used as paleotemperature proxies, but on long timescales, they also hold the potential to reconstruct past seawater Mg / Ca. The impact of both temperature and seawater Mg / Ca on Mg incorporation in Foraminifera has been quantified by a number of

  15. Shelf edge regime and foraminifera off Pondicherry, Bay of Bengal

    Digital Repository Service at National Institute of Oceanography (India)

    Setty, M.G.A.P.

    Amphistegina, Borelis, Operculina, Operculinoides@@, the Peneroplidae, and the Miliolidae may be due, in part, to their survival over long periods of time and also to their continued existence even today. Some species have a wider range of distribution extending from...

  16. Ocean acidification induces biochemical and morphological changes in the calcification process of large benthic foraminifera.

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    Prazeres, Martina; Uthicke, Sven; Pandolfi, John M

    2015-03-22

    Large benthic foraminifera are significant contributors to sediment formation on coral reefs, yet they are vulnerable to ocean acidification. Here, we assessed the biochemical and morphological impacts of acidification on the calcification of Amphistegina lessonii and Marginopora vertebralis exposed to different pH conditions. We measured growth rates (surface area and buoyant weight) and Ca-ATPase and Mg-ATPase activities and calculated shell density using micro-computer tomography images. In A. lessonii, we detected a significant decrease in buoyant weight, a reduction in the density of inner skeletal chambers, and an increase of Ca-ATPase and Mg-ATPase activities at pH 7.6 when compared with ambient conditions of pH 8.1. By contrast, M. vertebralis showed an inhibition in Mg-ATPase activity under lowered pH, with growth rate and skeletal density remaining constant. While M. vertebralis is considered to be more sensitive than A. lessonii owing to its high-Mg-calcite skeleton, it appears to be less affected by changes in pH, based on the parameters assessed in this study. We suggest difference in biochemical pathways of calcification as the main factor influencing response to changes in pH levels, and that A. lessonii and M. vertebralis have the ability to regulate biochemical functions to cope with short-term increases in acidity. © 2015 The Author(s) Published by the Royal Society. All rights reserved.

  17. Larger foraminifera distribution on a mesotrophic carbonate shelf in SW Sulawesi (Indonesia)

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    Renema, W.; Troelstra, S.R.

    2001-01-01

    Larger symbiont bearing foraminifera typically live in shallow tropical seas. In this study the fauna composition of patch reefs scattered over the Spermonde Shelf (SW Sulawesi, Indonesia), a mesotrophic carbonate shelf, is examined. The foraminiferal fauna of the Spermonde Shelf is characterised by

  18. Oxygen isotope fractionation and algal symbiosis in benthic foraminifera from the Gulf of Elat, Israel

    International Nuclear Information System (INIS)

    Buchardt, B.; Hansen, H.J.

    1977-01-01

    In order to investigate possible isotopic fractionations due to algal symbiosis the oxygen and carbon isotope compositions of shell carbonate from symbiont-free and symbiont-bearing benthic foraminifera have been compared to that of molluscs living at the same locality. The material was collected over a depth profile in the Gulf of Elat (Aqaba), Israel, covering the interval from 4 to 125 metres. After corrections variations for temperature with depth, characteristic 18 O-depletions were observed in the foraminiferal shell carbonate when compared to the molluscs. These depletions are interpreted as 1) a constant vital effect seen in all the foraminifera studied and 2) an additional, light-dependent vital effect observed in the symbiont-bearing forms only, caused by incorporation of photosynthetic oxygen formed by the symbiotic algae. This additional vital effect emphasizes the difficulties in applying foraminifera to oxygen isotope palaeotemperature analyses. No well-defined differences in carbon isotope compositions are observed between symbiont-bearing and symbiont-free foraminifera. (author)

  19. Oxygen isotope fractionation and algal symbiosis in benthic foraminifera from the Gulf of Elat, Israel

    Energy Technology Data Exchange (ETDEWEB)

    Buchardt, B; Hansen, H J [Copenhagen Univ. (Denmark)

    1977-01-01

    In order to investigate possible isotopic fractionations due to algal symbiosis the oxygen and carbon isotope compositions of shell carbonate from symbiont-free and symbiont-bearing benthic foraminifera have been compared to that of molluscs living at the same locality. The material was collected over a depth profile in the Gulf of Elat (Aqaba), Israel, covering the interval from 4 to 125 metres. After correcting for variations of temperature with depth, characteristic /sup 18/O-depletions were observed in the foraminiferal shell carbonate when compared to the molluscs. These depletions are interpreted as 1) a constant vital effect seen in all the foraminifera studied and 2) an additional, light-dependent vital effect observed in the symbiont-bearing forms only, caused by incorporation of photosynthetic oxygen formed by the symbiotic algae. This additional vital effect emphasizes the difficulties in applying foraminifera to oxygen isotope palaeotemperature analyses. No well-defined differences in carbon isotope compositions are observed between symbiont-bearing and symbiont-free foraminifera.

  20. Effects of lead pollution on Ammonia parkinsoniana (foraminifera): ultrastructural and microanalytical approaches.

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    Frontalini, F; Curzi, D; Giordano, F M; Bernhard, J M; Falcieri, E; Coccioni, R

    2015-01-30

    The responses of Ammonia parkinsoniana (Foraminifera) exposed to different concentrations of lead (Pb) were evaluated at the cytological level. Foraminifera-bearing sediments were placed in mesocosms that were housed in aquaria each with seawater of a different lead concentration. On the basis of transmission electron microscopy and environmental scanning electron microscopy coupled with energy dispersive spectrometer analyses, it was possible to recognize numerous morphological differences between untreated (i.e., control) and treated (i.e., lead enrichment) specimens. In particular, higher concentrations of this pollutant led to numerical increase of lipid droplets characterized by a more electron-dense core, proliferation of residual bodies, a thickening of the organic lining, mitochondrial degeneration, autophagosome proliferation and the development of inorganic aggregates.  All these cytological modifications might be related to the pollutant-induced stress and some of them such as the thickening of organic lining might suggest a potential mechanism of protection adopted by foraminifera.

  1. Foraminifera and changing pattern of monsoon rainfall

    Digital Repository Service at National Institute of Oceanography (India)

    Nigam, R.

    The palaeomonsoonal history can be reconstructed utilizing climatically sensitive properties of marine microorganisms; foraminifera. The results show a major boundary at 3500 years B.P. and periods of rather low precipitation approximately at 420...

  2. Foraminifera from the deep lake terraces, Vestfold hills, Antarctica

    Digital Repository Service at National Institute of Oceanography (India)

    Setty, M.G.A.P.; Williams, R.; Kerry, K.R.

    regarding disparity in abundance (paucity or even absence) of foraminifera in samples from identical elevations in the two transects are proposed: differential wind erosion occurred and foraminifera were deposited elsewhere; the faunas are remnants of debris...

  3. Automated species-level identification and segmentation of planktonic foraminifera using convolutional neural networks

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    Marchitto, T. M., Jr.; Mitra, R.; Zhong, B.; Ge, Q.; Kanakiya, B.; Lobaton, E.

    2017-12-01

    Identification and picking of foraminifera from sediment samples is often a laborious and repetitive task. Previous attempts to automate this process have met with limited success, but we show that recent advances in machine learning can be brought to bear on the problem. As a `proof of concept' we have developed a system that is capable of recognizing six species of extant planktonic foraminifera that are commonly used in paleoceanographic studies. Our pipeline begins with digital photographs taken under 16 different illuminations using an LED ring, which are then fused into a single 3D image. Labeled image sets were used to train various types of image classification algorithms, and performance on unlabeled image sets was measured in terms of precision (whether IDs are correct) and recall (what fraction of the target species are found). We find that Convolutional Neural Network (CNN) approaches achieve precision and recall values between 80 and 90%, which is similar precision and better recall than human expert performance using the same type of photographs. We have also trained a CNN to segment the 3D images into individual chambers and apertures, which can not only improve identification performance but also automate the measurement of foraminifera for morphometric studies. Given that there are only 35 species of extant planktonic foraminifera larger than 150 μm, we suggest that a fully automated characterization of this assemblage is attainable. This is the first step toward the realization of a foram picking robot.

  4. Distribution of foraminifera in the lagoons of certain Islands of the Lakshadweep Archipelago, Arabian Sea

    Digital Repository Service at National Institute of Oceanography (India)

    Rao, K.K; Sivadas, P.; Narayanan, B.; Jayalakshmy, K; Kutty, M.K

    , but arenaceous forms are very rare due to coarse nature of the deposits. Of the families observed, Miliolidae, Calcarinidae, and Amphisteginidae are most abundant and 2 species, Calcarina calcar and Amphistegina radiata are the most dominant. Planktonic...

  5. TOF-SIMS characterization of planktonic foraminifera

    International Nuclear Information System (INIS)

    Vering, G.; Crone, C.; Bijma, J.; Arlinghaus, H.F.

    2003-01-01

    Oceanic sediment properties that are closely related to former environmental (e.g. climatic) parameters are called 'proxies'. Planktonic foraminifera are small protists which make up part of the plankton. Certain element concentrations, element ratios and isotopic ratios of their calcite shell found in the sediment can be used as proxies reflecting the state of the ocean during the life of the animal; they supply useful information for the reconstruction of environmental parameters. Time-of-flight secondary ion mass spectrometry (TOF-SIMS) was used to examine the inner and outer part of foraminiferal shells, as well as foraminiferal shells dissolved in HCl. High resolution elemental images and mass spectra were obtained from the foraminifera. The data show that TOF-SIMS is a useful technique for determining the elemental distribution and for measuring isotope ratios such as δ 11 B with high precision in a single foraminiferal shell

  6. TOF-SIMS characterization of planktonic foraminifera

    Energy Technology Data Exchange (ETDEWEB)

    Vering, G.; Crone, C.; Bijma, J.; Arlinghaus, H.F

    2003-01-15

    Oceanic sediment properties that are closely related to former environmental (e.g. climatic) parameters are called 'proxies'. Planktonic foraminifera are small protists which make up part of the plankton. Certain element concentrations, element ratios and isotopic ratios of their calcite shell found in the sediment can be used as proxies reflecting the state of the ocean during the life of the animal; they supply useful information for the reconstruction of environmental parameters. Time-of-flight secondary ion mass spectrometry (TOF-SIMS) was used to examine the inner and outer part of foraminiferal shells, as well as foraminiferal shells dissolved in HCl. High resolution elemental images and mass spectra were obtained from the foraminifera. The data show that TOF-SIMS is a useful technique for determining the elemental distribution and for measuring isotope ratios such as {delta}{sup 11}B with high precision in a single foraminiferal shell.

  7. Vertical distribution of living mangrove foraminifera from KwaZulu ...

    African Journals Online (AJOL)

    Previous intertidal foraminiferal studies have predominantly focused on assemblages in surface sediments (0–1 cm), with the rationale that surface assemblages reflect the modern-day environment. Foraminifera live infaunally and therefore there is a need to document the infaunal vertical distribution of living foraminifera to ...

  8. Larger foraminifera from a relict structure off Karwar western Indian continental margin

    Digital Repository Service at National Institute of Oceanography (India)

    Setty, M.G.A.P.

    of such water masses having been present in the region. Among the larger forms, @iAmphistegina bicirculata, A. radiata@@ var. @ipapillosa@@ and @iOperculina ammonoides@@ indicate mixing, while @iNummulites cumingii@@ and @iBorelis schlumbergeri@@ were relict...

  9. Testing the Molecular Clock Using the Best Fossil Record: Case Studies from the Planktic Foraminifera

    Science.gov (United States)

    Steel, B. A.; Kucera, M.; Darling, K.

    2004-12-01

    derived AƒAøAøâ_sA¬A<Å"pinkAƒAøAøâ_sA¬Aøâ_zAø form may have been artificially truncated by diagenetic degradation of the meta-stable test pigmentation. The deep molecular splits for Gl. siphonifera (around 7 Ma for the two main morphologically distinguishable sub-types), whilst not so obviously at odds with the fossil record, still belie the very small amount of morphological evolution observed within the plexus. We have used morphometric methods on a large (over 2000 pooled specimens) dataset in an effort to independently test the molecular clock, using SEM-based measurement of pore metrics (for Gl. siphonifera) and a multivariate analysis of whole-test characteristics (for Gs. ruber). Comparison of results for the two species suggests interesting patterns; whilst the two cryptic sub-types of Gl. siphonifera seemingly can be traced through time and seem to respond to external oceanographic forcing, the sub-types of Gs. ruber appear to be truly cryptic, and cannot be distinguished in the fossil record beyond 0.7 Ma. This raises two important points; firstly, the molecular clock (at least for foraminifera) bears considerable scrutiny, appears to be relatively robust to substitution bias and is seemingly broadly in accordance with morphological data; and secondly, the relationship between form and function in planktic foraminifera appears to be ill-defined, raising important questions for functional morphology.

  10. Intertidal foraminifera from Miramar-Caranzalem Shoreline, Goa

    Digital Repository Service at National Institute of Oceanography (India)

    Setty, M.G.A.P.; Birajdar, S.M.; Nigam, R.

    Quantitative analysis of foraminifera (entire and broken) revealed that Rotalina, composed of 29 species, constituted 95.18% while Miliolina, composed of 11 species, and Textulariina, with 5 species were poorly represented. Temperature, salinity...

  11. Living planktonic foraminifera of the Wadge bank, Northern Indian Ocean

    Digital Repository Service at National Institute of Oceanography (India)

    Rao, K.K.; Jayalakshmy, K.V.; Panikkar, B.M.; Kutty, M.K.

    Twenty three species of living planktonic Foraminifera belonging to 11 genera have been studied from the Wadge Bank area off southern tip of the Indian peninsula. The fauna is characterized by species such as Globigerinoides conglobatus, G...

  12. Counts of Foraminifera from Selected North Atlantic Cores, LDEO

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Counts of primarily planktonic foraminifera from Dr. W.F. Ruddiman and staff at the Lamont-Doherty Earth Observatory of Columbia University are included in these...

  13. Benthic Foraminifera as ecological indicators for water quality on the Great Barrier Reef

    Science.gov (United States)

    Uthicke, Sven; Nobes, Kristie

    2008-07-01

    Benthic foraminifera are established indicators for Water Quality (WQ) in Florida and the Caribbean. However, nearshore coral reefs of the Great Barrier Reef (GBR) and other Pacific regions are also subjected to increased nutrient and sediment loads. Here, we investigate the use of benthic foraminifera as indicators to assess status and trends of WQ on GBR reefs. We quantified several sediment parameters and the foraminiferan assemblage composition on 20 reefs in four geographic regions of the GBR, and along a water column nutrient and turbidity gradient. Twenty-seven easily recognisable benthic foraminiferan taxa (>63 μm) were distinguished. All four geographic regions differed significantly ( p turbid inner shelf towards clearer outer shelf reefs. A RDA separated symbiotic and aposymbiotic (heterotrophic) taxa. In addition, total suspended solid and water column chlorophyll a concentrations were negatively correlated, and optical depth and distance to the mainland were positively correlated, with the abundance of symbiont-bearing taxa. Several large foraminifera were identified as indicators for offshore, clear water conditions. In contrast, heterotrophic rotaliids and a species retaining plastids ( Elphidium sp.) where highly characteristic for low light, higher nutrient conditions. Application of the FORAM index to GBR assemblage composition showed a significant increase in the value of this index with increased distance from the mainland in the Whitsunday region ( r2 = 0.75, p < 0.001), and therefore with increasing light and decreased nutrient availability. We conclude that it will be possible to apply this index to GBR and possibly other Pacific reefs after some adaptations and additional experimental work on species-specific limiting factors.

  14. Benthic foraminifera as proxy for oxygen-depleted conditions off the central west coast of India

    Digital Repository Service at National Institute of Oceanography (India)

    Nigam, R.; Mazumder, A.; Henriques, P.J.; Saraswat, R.

    In order to study the response of benthic foraminifera, especially the rectilinear bi- and tri-serial benthic foraminifera (RBF) to oxygen-depleted conditions from the Arabian Sea off central west coast of India, 103 surface sediment samples...

  15. Bearing system

    Science.gov (United States)

    Kapich, Davorin D.

    1987-01-01

    A bearing system includes backup bearings for supporting a rotating shaft upon failure of primary bearings. In the preferred embodiment, the backup bearings are rolling element bearings having their rolling elements disposed out of contact with their associated respective inner races during normal functioning of the primary bearings. Displacement detection sensors are provided for detecting displacement of the shaft upon failure of the primary bearings. Upon detection of the failure of the primary bearings, the rolling elements and inner races of the backup bearings are brought into mutual contact by axial displacement of the shaft.

  16. Effect of ocean acidification on the benthic foraminifera

    NARCIS (Netherlands)

    Keul, N.; Langer, G.; de Nooijer, L.J.; Bijma, J.

    2013-01-01

    About 30% of the anthropogenically released CO2 is taken up by the oceans; such uptake causes surface ocean pH to decrease and is commonly referred to as ocean acidification (OA). Foraminifera are one of the most abundant groups of marine calcifiers, estimated to precipitate ca. 50 % of biogenic

  17. Benthic foraminifera from the Adriatic Sea : principles of phenotypic variation

    NARCIS (Netherlands)

    Jorissen, F.J.

    1988-01-01

    The distribution and morphology of the benthic foraminifera in the Adriatic Sea appear to be strongly dependent on two primary controlling environmental parameters, oxygen concentration and food availability. These factors are both governed by the runoff from the Po and other Italian rivers, and

  18. On the phylogeny of the embryonic apparatus of some Foraminifera

    NARCIS (Netherlands)

    Cosijn, A.J.

    1942-01-01

    In the following pages data will be given about the size of the megalospheric embryonic apparatus, and of the size of the shell, of some Foraminifera. By comparing these data for a certain species from different samples, the relative ages of which are known, it will be possible, to get an insight

  19. Ecological partitioning and diversity in tropical planktonic foraminifera

    Directory of Open Access Journals (Sweden)

    Seears Heidi A

    2012-04-01

    Full Text Available Abstract Background Ecological processes are increasingly being viewed as an important mode of diversification in the marine environment, where the high dispersal potential of pelagic organisms, and a lack of absolute barriers to gene flow may limit the occurrence of allopatric speciation through vicariance. Here we focus on the potential role of ecological partitioning in the diversification of a widely distributed group of marine protists, the planktonic foraminifera. Sampling was conducted in the tropical Arabian Sea, during the southwest (summer monsoon, when pronounced environmental conditions result in a strong disparity in temperature, salinity and productivity between distinct northern and southern water masses. Results We uncovered extensive genetic diversity within the Arabian Sea planktonic foraminifera, identifying 13 morphospecies, represented by 20 distinct SSU rRNA genetic types. Several morphospecies/genetic types displayed non-random biogeographical distributions, partitioning between the northern and southern water masses, giving a strong indication of independent ecological adaptations. Conclusions We propose sea-surface primary productivity as the main factor driving the geographical segregation of Arabian Sea planktonic foraminifera, during the SW monsoon, with variations in symbiotic associations possibly playing a role in the specific ecological adaptations observed. Our findings suggest that ecological partitioning could be contributing to the high levels of 'cryptic' genetic diversity observed within the planktonic foraminifera, and support the view that ecological processes may play a key role in the diversification of marine pelagic organisms.

  20. Frequency distribution of foraminifera off Trivandrum, west coast of India

    Digital Repository Service at National Institute of Oceanography (India)

    Rao, K.K.; Kutty, M.K.; Panikkar, B.M.

    Fifty two species belonging to 31 genera of recent foraminifera have been identified from sediment samples collected from the inshore waters. Based on relative abundance of species, it is observed that along the coast, the nearshore region up to 5 m...

  1. Microfacies analysis of foraminifera rich sedimentary rocks from the Desert Plateau, central Egypt.

    Science.gov (United States)

    Karnitschar, C.; Briguglio, A.; Hohenegger, J.

    2012-04-01

    Microfacies analysis on some samples from the Thebes Group have been carried on by means of thin sections. The study area is included in the Libyan Desert Plateau (central Egypt) at following coordinates N27° 36'30.58" E29° 44'58.34", near the biggest dune of Egypt, the Ghard Abu Muharik. Because of the round shape of the rocks and the desert patina on the surface they could easily be classified as the so called "Melonstones", which are located more southwards and mainly composed by stromatolites. On the contrary, the investigated samples show a completely different fauna and therefore have been separated from the "Melonstones". Even if shape and size are very similar and the desert patina covers all surfaces the same way the differences are impressive. To investigate the samples, two thin-sections have been prepared and analyzed at the microscope. The observed fauna is composed by: agglutinated benthic foraminifera (e.g., Dictyoconus egypticus), complex larger miliolids (e.g., Pseudolacazina cf. danatae, Fabularia sp.), alveolinids (Alveolina vredenburgi), green algae (Dasycladaceae), echinoids and corals. Because of the presence of symbionts bearing larger benthic foraminifera, which need light to feed photosymbionts, the rock was formed in a shallow water environment. With the abundant rock-building benthic foraminifera and calcareous algae the limestone shows a tendency to the packstone/wackestone facies. Based on the presence of Alveolina vredenburgi, the age of the samples can be estimate as lowermost Eocene belonging to the shallow benthic zone 5 (sensu Serra-Kiel et al., 1998). According the obtained data on stratigraphy and palaeoecology, a partial palaeoenvironmental reconstruction is possible for the Libyan Desert Plateau where outcrops are largely missing. Because of the round shape of the samples and the patina which covers them all around it can be assumed that they have been transported from longer distance. According to the geological map of the

  2. The evolution of test size in the Planktic Foraminifera

    Science.gov (United States)

    Fraass, A.; Huber, B. T.; Kelly, D. C.

    2017-12-01

    Planktic foraminifera are vital tools for understanding paleoceanography, paleoclimate, and evolution. A dataset of measurements from all planktic foraminiferal species is used here to investigate how their size changes through the late Jurassic to Recent. The mean test size of planktic foraminifera increases in the Cretaceous and the Cenozoic, with substantial drops at the Aptian/Albian boundary, in the Coniacian and Santonian, with the end-Cretaceous extinction, and across the Paleocene/Eocene boundary. The Oligocene contains only a small drop in mean size, which is surprising given the substantial extinction of planktic foraminifera at that boundary. There is a qualitative connection between mean and median size and paleoceanographic events, but several key issues remain before rigorous quantitative interrogation of the dataset can be undertaken. In general, species that originate early in a family's range are smaller than those evolving later, though this is a weak relationship. Individual families do not always conform to that finding, however, and have both increasing and decreasing family age-size relationships. The 'three faunas' concept for foraminiferal evolution fails with respect to mean and median size; each diversification has a unique rate of increase and character. Lastly, through comparison with the Schmidt et al. (2004) population-level test size dataset, the size response to climate in the low-latitudes is at the species-level. In the high-latitude regions, however, the response to climate is at the population level. Thus, methods for uncovering climate responses in planktic foraminifera must be specific to the region. Taxonomic or macroevolutionary responses dominate the tropics and global signals, while the polar regions appear to have a unique, and more microevolutionary response.Schmidt, D., Thierstein, H., Bollmann, J., & Schiebel, R. (2004). Abiotic Forcing of Plankton Evolution in the Cenozoic. Science, 303(5655), 207-210.

  3. Planktic foraminifera form their shells via metastable carbonate phases

    OpenAIRE

    Jacob, D. E.; Wirth, R.; Agbaje, O. B. A.; Branson, O.; Eggins, S. M.

    2017-01-01

    The calcium carbonate shells of planktic foraminifera provide our most valuable geochemical archive of ocean surface conditions and climate spanning the last 100 million years, and play an important role in the ocean carbon cycle. These shells are preserved in marine sediments as calcite, the stable polymorph of calcium carbonate. Here, we show that shells of living planktic foraminifers Orbulina universa and Neogloboquadrina dutertrei originally form from the unstable calcium carbonate polym...

  4. MIDDLE TRIASSIC FORAMINIFERA FROM THE SECEDA CORE (DOLOMITES, NORTHERN ITALY

    Directory of Open Access Journals (Sweden)

    FLORIAN MAURER

    2002-11-01

    Full Text Available The assemblage of foraminifera in turbidite beds in Middle Triassic basinal deposits straddling the Anisian/Ladinian boundary interval was studied in 224 thin sections. The fauna consists mainly of shallow-water inhabitants, associated with calcareous hyaline foraminifera (Lagenina of open marine environment. Due to a well established  biostratigraphy in the studied interval, the first and last appearance of some shallow water, benthic foraminifera can be assigned to the Mid Triassic ammonoid stratigraphy. The species Meandrospira dinarica Kochansky-Devidè & Pantic and Arenovidalina chialingchiagensis Ho are limited to the Reitzi ammonoid zone. The species Variostoma alta Kristan and Hoyenella gr. sinensis both do not superate the Curionii zone in age in the studied succession.  The biostratigraphic most important event occurs at the base of the Gredleri zone,  with the appearance of the family Involutinidae Bütschli, represented by the genera Lamelliconus and Aulotortus. The faunal composition is similar to those of neighbouring paleoprovinces, but generally a lower faunistical diversification compared to foraminiferal assemblages in the Anisian or Carnian is observed.   

  5. Morphological and cytological responses of Ammonia (foraminifera) to copper contamination: Implication for the use of foraminifera as bioindicators of pollution

    International Nuclear Information System (INIS)

    Le Cadre, Valerie; Debenay, Jean-Pierre

    2006-01-01

    The effect of graded concentrations of copper was analyzed at morphological and cytological levels on two species of Ammonia (foraminifera) often found in polluted areas. The two species were sensitive to low concentration, but survived high concentration (threshold value -1 , lethal value > 200 μg l -1 ), which gives them a high potential value as bioindicators. Increasing concentrations lead to (1) increasing delay before production of new chambers, explaining dwarfism in polluted areas; (2) increasing delay before reproduction and decreasing number of juveniles, explaining low density; and (3) increasing proportion of deformed tests. Cytological modifications occurred only in deformed specimens (thickening of the organic lining, proliferation of fibrillar and of large lipidic vesicles, increased number of residual bodies). They may be responsible for anomalies in biomineralization processes. The detection of sulfur in deformed specimens suggests that foraminifers may have a detoxification mechanism with production of a metallothionein-like protein. - Results suggest a detoxification mechanism for copper in foraminifera

  6. Journal bearing

    Science.gov (United States)

    Menke, John R.; Boeker, Gilbert F.

    1976-05-11

    1. An improved journal bearing comprising in combination a non-rotatable cylindrical bearing member having a first bearing surface, a rotatable cylindrical bearing member having a confronting second bearing surface having a plurality of bearing elements, a source of lubricant adjacent said bearing elements for supplying lubricant thereto, each bearing element consisting of a pair of elongated relatively shallowly depressed surfaces lying in a cylindrical surface co-axial with the non-depressed surface and diverging from one another in the direction of rotation and obliquely arranged with respect to the axis of rotation of said rotatable member to cause a flow of lubricant longitudinally along said depressed surfaces from their distal ends toward their proximal ends as said bearing members are rotated relative to one another, each depressed surface subtending a radial angle of less than 360.degree., and means for rotating said rotatable bearing member to cause the lubricant to flow across and along said depressed surfaces, the flow of lubricant being impeded by the non-depressed portions of said second bearing surface to cause an increase in the lubricant pressure.

  7. Patterns of species richness and the center of diversity in modern Indo-Pacific larger foraminifera.

    Science.gov (United States)

    Förderer, Meena; Rödder, Dennis; Langer, Martin R

    2018-05-29

    Symbiont-bearing Larger Benthic Foraminifera (LBF) are ubiquitous components of shallow tropical and subtropical environments and contribute substantially to carbonaceous reef and shelf sediments. Climate change is dramatically affecting carbonate producing organisms and threatens the diversity and structural integrity of coral reef ecosystems. Recent invertebrate and vertebrate surveys have identified the Coral Triangle as the planet's richest center of marine life delineating the region as a top priority for conservation. We compiled and analyzed extensive occurrence records for 68 validly recognized species of LBF from the Indian and Pacific Ocean, established individual range maps and applied Minimum Convex Polygon (MCP) and Species Distribution Model (SDM) methodologies to create the first ocean-wide species richness maps. SDM output was further used for visualizing latitudinal and longitudinal diversity gradients. Our findings provide strong support for assigning the tropical Central Indo-Pacific as the world's species-richest marine region with the Central Philippines emerging as the bullseye of LBF diversity. Sea surface temperature and nutrient content were identified as the most influential environmental constraints exerting control over the distribution of LBF. Our findings contribute to the completion of worldwide research on tropical marine biodiversity patterns and the identification of targeting centers for conservation efforts.

  8. GAS BEARING

    Science.gov (United States)

    Skarstrom, C.W.

    1960-09-01

    A gas lubricated bearing for a rotating shaft is described. The assembly comprises a stationary collar having an annular member resiliently supported thereon. The collar and annular member are provided with cooperating gas passages arranged for admission of pressurized gas which supports and lubricates a bearing block fixed to the rotatable shaft. The resilient means for the annular member support the latter against movement away from the bearing block when the assembly is in operation.

  9. Grizzly bear

    Science.gov (United States)

    Schwartz, C.C.; Miller, S.D.; Haroldson, M.A.; Feldhamer, G.; Thompson, B.; Chapman, J.

    2003-01-01

    The grizzly bear inspires fear, awe, and respect in humans to a degree unmatched by any other North American wild mammal. Like other bear species, it can inflict serious injury and death on humans and sometimes does. Unlike the polar bear (Ursus maritimus) of the sparsely inhabited northern arctic, however, grizzly bears still live in areas visited by crowds of people, where presence of the grizzly remains physically real and emotionally dominant. A hike in the wilderness that includes grizzly bears is different from a stroll in a forest from which grizzly bears have been purged; nighttime conversations around the campfire and dreams in the tent reflect the presence of the great bear. Contributing to the aura of the grizzly bear is the mixture of myth and reality about its ferocity. unpredictable disposition, large size, strength, huge canines, long claws, keen senses, swiftness, and playfulness. They share characteristics with humans such as generalist life history strategies. extended periods of maternal care, and omnivorous diets. These factors capture the human imagination in ways distinct from other North American mammals. Precontact Native American legends reflected the same fascination with the grizzly bear as modern stories and legends (Rockwell 1991).

  10. Ecology of planktonic foraminifera and their symbiotic algae

    International Nuclear Information System (INIS)

    Gastrich, M.D.

    1986-01-01

    Two types of symbiotic algae occurred abundantly and persistently in the cytoplasm of several species of planktonic Foraminifera over a ten year period in different tropical and subtropical areas of the North Atlantic Ocean. These planktonic Foraminifera host species consistently harbored either dinoflagellates or a newly described minute coccoid algal type. There appeared to be a specific host-symbiont relationship in these species regardless of year, season or geographic locality. The larger ovoid dinoflagellates (Pyrrhophycophyta) occur in the spinose species Globigerinoides ruber, Globigerinoides sacculifer, G. conglobatus and Orbulina universa. The smaller alga, from 1.5 to 3.5 um in diameter, occurs in one spinose species Globigerinella aequilateralis and also in the non-spinose species Globigerinita glutinata, Globoquadrina dutertrei, Globorotalia menardii, Globorotalia cristata, Globorotalia inflata, Candeina nitida, in various juvenile specimens and at all seasons except the winter months in Pulleniatina obliquiloculata and Globorotalial hirsuta. Controlled laboratory studies indicated a significant C incorporation into the host cytoplasm and inorganic calcium carbonate test of Globigerinoides ruber. During incubation for up to two hours, the 14 C uptake into the cytoplasm and test in the light was significantly greater than uptake in the dark by living specimens or by dead foraminifers. There appears to be light-enhanced uptake of 14 C into the test with dinoflagellate photosynthesis contributing to host calcification. In culture, symbiotic algae were observed to survive for the duration of the lifespan of their hosts

  11. Salinity controls on Na incorporation in Red Sea planktonic foraminifera

    Science.gov (United States)

    Mezger, E. M.; de Nooijer, L. J.; Boer, W.; Brummer, G. J. A.; Reichart, G. J.

    2016-12-01

    Whereas several well-established proxies are available for reconstructing past temperatures, salinity remains challenging to assess. Reconstructions based on the combination of (in)organic temperature proxies and foraminiferal stable oxygen isotopes result in relatively large uncertainties, which may be reduced by application of a direct salinity proxy. Cultured benthic and planktonic foraminifera showed that Na incorporation in foraminiferal shell calcite provides a potential independent proxy for salinity. Here we present the first field calibration of such a potential proxy. Living planktonic foraminiferal specimens from the Red Sea surface waters were collected and analyzed for their Na/Ca content using laser ablation quadrupole inductively coupled plasma mass spectrometry. Using the Red Sea as a natural laboratory, the calibration covers a broad range of salinities over a steep gradient within the same water mass. For both Globigerinoides ruber and Globigerinoides sacculifer calcite Na/Ca increases with salinity, albeit with a relatively large intraspecimen and interspecimen variability. The field-based calibration is similar for both species from a salinity of 36.8 up to 39.6, while values for G. sacculifer deviate from this trend in the northernmost transect. It is hypothesized that the foraminifera in the northernmost part of the Red Sea are (partly) expatriated and hence should be excluded from the Na/Ca-salinity calibration. Incorporation of Na in foraminiferal calcite therefore provides a potential proxy for salinity, although species-specific calibrations are still required and more research on the effect of temperature is needed.

  12. An endemic post-CTB Pseudorhapydionina (foraminifera) from the Pyrenean palaeobioprovince

    Science.gov (United States)

    Consorti, Lorenzo; Caus, Esmeralda

    2015-04-01

    and Orbitokathina vonderschmitti, among others. All of this fauna that seems restricted to the Pyrenean palaeobioprovince are late Cretaceous GCMC newcomers. Thus, the presence of such morphotype in the deposits of the Late Cretaceous GCMC of the Pyrenean palaeobioprovincie arises the followings questions: is the Pyrenean taxon a CTB survivor? Or, are we faced with a morphological convergence? Positive answering to the first question would implicate that Pseudorhapydionina could have successfully migrated from the western Tethyan (Iberian Basin) to the Pyrenean Basin before the communication was stopped, without reaching an appropriate colonizing area, probably due to the different oceanographic conditions. But, the change of those conditions during the late Coniacian- early Santonian times, as it is demonstrated by the abundance of symbiont-bearing LBF taxa, had favored the installation of Pseudorhapydionina in the Santonian shallow-water environments. The hypothesis of a morphological convergence could be explained by the quite simple architecture of the present taxon. Notwithstanding, following the actual taxonomical classification in foraminifera, the presence of radial septula, which does not alternate with the intercameral foramina, and the absence of pillars definitively ascribed our specimens to the genus Pseudorhapydionina.

  13. Morphological and cytological responses of Ammonia (foraminifera) to copper contamination: Implication for the use of foraminifera as bioindicators of pollution

    Energy Technology Data Exchange (ETDEWEB)

    Le Cadre, Valerie [Universite d' Angers, UPRES-EA 2644, Laboratoire de Geologie, 2 Bd Lavoisier 49045 Angers cedex (France) and LEBIM - Laboratoire d' Etude des Bio-Indicateurs Marins, 85350 Ile d' Yeu (France)]. E-mail: val.jeje@wanadoo.fr; Debenay, Jean-Pierre [Universite d' Angers, UPRES-EA 2644, Laboratoire de Geologie, 2 Bd Lavoisier 49045 Angers cedex (France); LEBIM - Laboratoire d' Etude des Bio-Indicateurs Marins, 85350 Ile d' Yeu (France)

    2006-09-15

    The effect of graded concentrations of copper was analyzed at morphological and cytological levels on two species of Ammonia (foraminifera) often found in polluted areas. The two species were sensitive to low concentration, but survived high concentration (threshold value < 10 {mu}g l{sup -1}, lethal value > 200 {mu}g l{sup -1}), which gives them a high potential value as bioindicators. Increasing concentrations lead to (1) increasing delay before production of new chambers, explaining dwarfism in polluted areas; (2) increasing delay before reproduction and decreasing number of juveniles, explaining low density; and (3) increasing proportion of deformed tests. Cytological modifications occurred only in deformed specimens (thickening of the organic lining, proliferation of fibrillar and of large lipidic vesicles, increased number of residual bodies). They may be responsible for anomalies in biomineralization processes. The detection of sulfur in deformed specimens suggests that foraminifers may have a detoxification mechanism with production of a metallothionein-like protein. - Results suggest a detoxification mechanism for copper in foraminifera.

  14. Automatic Picking of Foraminifera: Design of the Foraminifera Image Recognition and Sorting Tool (FIRST) Prototype and Results of the Image Classification Scheme

    Science.gov (United States)

    de Garidel-Thoron, T.; Marchant, R.; Soto, E.; Gally, Y.; Beaufort, L.; Bolton, C. T.; Bouslama, M.; Licari, L.; Mazur, J. C.; Brutti, J. M.; Norsa, F.

    2017-12-01

    Foraminifera tests are the main proxy carriers for paleoceanographic reconstructions. Both geochemical and taxonomical studies require large numbers of tests to achieve statistical relevance. To date, the extraction of foraminifera from the sediment coarse fraction is still done by hand and thus time-consuming. Moreover, the recognition of morphotypes, ecologically relevant, requires some taxonomical skills not easily taught. The automatic recognition and extraction of foraminifera would largely help paleoceanographers to overcome these issues. Recent advances in automatic image classification using machine learning opens the way to automatic extraction of foraminifera. Here we detail progress on the design of an automatic picking machine as part of the FIRST project. The machine handles 30 pre-sieved samples (100-1000µm), separating them into individual particles (including foraminifera) and imaging each in pseudo-3D. The particles are classified and specimens of interest are sorted either for Individual Foraminifera Analyses (44 per slide) and/or for classical multiple analyses (8 morphological classes per slide, up to 1000 individuals per hole). The classification is based on machine learning using Convolutional Neural Networks (CNNs), similar to the approach used in the coccolithophorid imaging system SYRACO. To prove its feasibility, we built two training image datasets of modern planktonic foraminifera containing approximately 2000 and 5000 images each, corresponding to 15 & 25 morphological classes. Using a CNN with a residual topology (ResNet) we achieve over 95% correct classification for each dataset. We tested the network on 160,000 images from 45 depths of a sediment core from the Pacific ocean, for which we have human counts. The current algorithm is able to reproduce the downcore variability in both Globigerinoides ruber and the fragmentation index (r2 = 0.58 and 0.88 respectively). The FIRST prototype yields some promising results for high

  15. Planktic foraminifera form their shells via metastable carbonate phases.

    Science.gov (United States)

    Jacob, D E; Wirth, R; Agbaje, O B A; Branson, O; Eggins, S M

    2017-11-02

    The calcium carbonate shells of planktic foraminifera provide our most valuable geochemical archive of ocean surface conditions and climate spanning the last 100 million years, and play an important role in the ocean carbon cycle. These shells are preserved in marine sediments as calcite, the stable polymorph of calcium carbonate. Here, we show that shells of living planktic foraminifers Orbulina universa and Neogloboquadrina dutertrei originally form from the unstable calcium carbonate polymorph vaterite, implying a non-classical crystallisation pathway involving metastable phases that transform ultimately to calcite. The current understanding of how planktic foraminifer shells record climate, and how they will fare in a future high-CO 2 world is underpinned by analogy to the precipitation and dissolution of inorganic calcite. Our findings require a re-evaluation of this paradigm to consider the formation and transformation of metastable phases, which could exert an influence on the geochemistry and solubility of the biomineral calcite.

  16. Oxygen isotopic analyses of individual planktic foraminifera species: Implications for seasonality in the western Arabian Sea

    Digital Repository Service at National Institute of Oceanography (India)

    Naidu, P.D.; Niitsuma, N.; Naik, S.S.

    The variation of stable isotopes between individual shells of planktic foraminifera of a given species and size may provide short-term seasonal insight on Paleoceanography. In this context, oxygen isotope analyses of individual Globigerinoides...

  17. The relative sensitivity of benthonic foraminifera in the polluted marine environment of Cola Bay, Goa

    Digital Repository Service at National Institute of Oceanography (India)

    Setty, M.G.A.P.

    . The organic carbon content in the sediment is inversely proportional to the abundance of the benthonic populations. Living foraminifera are very useful in establishing zones of effects of pollutants in a region. Correlation coefficient between TFN and TSN...

  18. Planktonic foraminifera from a quaternary deep sea core from the southern Arabian Sea

    Digital Repository Service at National Institute of Oceanography (India)

    Naidu, P.D.; Rao, P.S.; Pattan, J.N.

    An investigation on planktonic foraminifera and calcium carbonate content of a box core collected at a depth of 2556 m from the southern part of the Arabian sea indicates faunal changes depicting Quaternary climatic fluctuations. Based on the study...

  19. The intriguing relationship between coiling direction and reproductive mode in benthic foraminifera

    Digital Repository Service at National Institute of Oceanography (India)

    Nigam, R.; Rao, A

    direction changes. The relationship between mode of reproduction and coiling directions in benthic foraminifera is explored. Benthic foraminiferal species Cavarotalia annectens (Paarker & Jones) in 58 samples obtained from a core off Karwar, west coast...

  20. Oxygen respiration rates of benthic foraminifera as measured with oxygen microsensors

    DEFF Research Database (Denmark)

    Geslin, E.; Risgaard-Petersen, N.; Lombard, Fabien

    2011-01-01

    of the foraminiferal specimens. The results show a wide range of oxygen respiration rates for the different species (from 0.09 to 5.27 nl cell−1 h−1) and a clear correlation with foraminiferal biovolume showed by the power law relationship: R = 3.98 10−3 BioVol0.88 where the oxygen respiration rate (R) is expressed......Oxygen respiration rates of benthic foraminifera are still badly known, mainly because they are difficult to measure. Oxygen respiration rates of seventeen species of benthic foraminifera were measured using microelectrodes and calculated on the basis of the oxygen fluxes measured in the vicinity...... groups (nematodes, copepods, ostracods, ciliates and flagellates) suggests that benthic foraminifera have a lower oxygen respiration rates per unit biovolume. The total contribution of benthic foraminifera to the aerobic mineralisation of organic matter is estimated for the studied areas. The results...

  1. Relationship between benthic foraminifera and sediment in the estuarine complex of Goa

    Digital Repository Service at National Institute of Oceanography (India)

    Dalal, S.G.

    Two indices of community association were used to elucidate the relationship between changes in species composition of benthic foraminifera and changes in the grain size composition of the sediment in estuarine complex of Goa. The degree...

  2. Sediment traps as a new tool for estimation of longevity of planktonic foraminifera

    Digital Repository Service at National Institute of Oceanography (India)

    Nigam, R.

    Sediment trap technique provides time series data of sinking particles (faunal and sediment) from surface to bottom of the sea. Besides many other applications, data can also be used to estimate life span of planktonic foraminifera. Based on rearing...

  3. Ecology and distribution of recent planktonic foraminifera in eastern part of Arabian Sea

    Digital Repository Service at National Institute of Oceanography (India)

    Rao, K.K.; Jayalakshmy, K.V.; Kutty, M.K.

    Thirty species of living planktonic foraminifera have been studied from 97 plankton tows collected from the eastern Arabian Sea with an accent on their ecological and distributional aspects. Species density is higher with less dominance in the deep...

  4. Proloculus size variation in Recent benthic foraminifera: Implications for paleoclimatic studies

    Digital Repository Service at National Institute of Oceanography (India)

    Nigam, R.; Rao, A.S.

    Ratios of dimorphic (microspheric/megalospheric) forms of Foraminifera are affected by temperature and hence are useful in paleoclimatic studies. In some cases, however, it is not possible to distinguish between the dimorphic forms and, therefore...

  5. Relationship between abundance and morphology of benthic foraminifera Epistominella exigua: Palaeoclimatic implications

    Digital Repository Service at National Institute of Oceanography (India)

    Saraswat, R.; Deopujari, A.; Nigam, R.; Henriques, P.J.

    The relationship between abundance (relative as well as absolute abundance) and morphology (size of the shell, numbers and proloculus size) of benthic foraminifera Epistominella exigua has been studied in a core to understand the influence...

  6. 70 kD stress protein (Hsp70) analysis in living shallow-water benthic foraminifera

    Digital Repository Service at National Institute of Oceanography (India)

    Heinz, P.; Marten, R.A; Linshy, V.N.; Haap, T.; Geslin, E.; Kohler, H-R.

    Hsp70 is a phylogenetically highly conserved protein family present in all eukaryotic organisms tested so far. Its synthesis is induced by proteotoxic stress. The detection of Hsp70 in foraminifera is presented here. We introduce a standard...

  7. Secondary calcification of planktic foraminifera from the Indian sector of Southern ocean

    Digital Repository Service at National Institute of Oceanography (India)

    Mohan, R.; Shetye, S.; Tiwari, M.; AnilKumar, N.

    This study focused on planktic foraminifera in plankton tows and surface sediments from the western Indian sector of Southern Ocean in order to evaluate the potential foraminiferal secondary calcification and/or dissolution in the sediment...

  8. The 'Natural Laboratory', a tool for deciphering growth, lifetime and population dynamics in larger benthic foraminifera

    Science.gov (United States)

    Hohenegger, Johann

    2015-04-01

    The shells of symbiont-bearing larger benthic Foraminifera (LBF) represent the response to physiological requirements in dependence of environmental conditions. All compartments of the shell such as chambers and chamberlets accommodate the growth of the cell protoplasm and are adaptations for housing photosymbiotic algae. Investigations on the biology of LBF were predominantly based on laboratory studies. The lifetime of LBF under natural conditions is still unclear. LBF, which can build >100 chambers during their lifetime, are thought to live at least one year under natural conditions. This is supported by studies on population dynamics of eulittoral foraminifera. In species characterized by a time-restricted single reproduction period the mean size of specimens increases from small to large during lifetime simultaneously reducing individual number. This becomes more complex when two or more reproduction times are present within a one-year cycle leading to a mixture of abundant small individuals with few large specimens during the year, while keeping mean size more or less constant. This mixture is typical for most sublittoral megalospheric (gamonts or schizonts) LBF. Nothing is known on the lifetime of agamonts, the diploid asexually reproducing generation. In all hyaline LBF it is thought to be significantly longer than 1 year based on the large size and considering the mean chamber building rate of the gamont/schizonts. Observations on LBF under natural conditions have not been performed yet in the deeper sublittoral. This reflects the difficulties due to intense hydrodynamics that hinder deploying technical equipment for studies in the natural environment. Therefore, studying growth, lifetime and reproduction of sublittoral LBF under natural conditions can be performed using the so-called 'natural laboratory' in comparison with laboratory investigations. The best sampling method in the upper sublittoral from 5 to 70 m depth is by SCUBA diving. Irregular

  9. Planktonic foraminifera in the Arctic: potentials and issues regarding modern and quaternary populations

    International Nuclear Information System (INIS)

    Eynaud, Frederique

    2011-01-01

    Calcareous microfossils are widely used by paleoceanographers to investigate past sea-surface hydrology. Among these microfossils, planktonic foraminifera are probably the most extensively used tool (e.g. [1] for a review), as they are easy to extract from the sediment and can also be used for coupled geochemical (e.g; δ 18 O, δ 13 C, Mg/Ca) and paleo-ecological investigations. Planktonic foraminifera are marine protists, which build a calcareous shell made of several chambers which reflect in their chemistry the properties of the ambient water-masses. Planktonic foraminifera are known to thrive in various habitats, distributed not only along a latitudinal gradient, but also along different water-depth intervals within surface waters (0-1000 m). Regarding their biogeographical distribution, planktonic foraminifera assemblages therefore mirror different water-masses properties, such as temperature, salinity and nutrient content of the surface water in which they live. The investigation of the specific composition of a fossil assemblage (relative abundances) is therefore a way to empirically obtain (paleo)information on past variations of sea-surface hydrological parameters. This paper focuses on the planktonic foraminifera record from the Arctic domain. This polar region records peculiar sea-surface conditions, with the influence of nearly perennial sea-ice cover development. This has strong impact on living foraminifera populations and on the preservation of their shells in the underlying sediments.

  10. Planktonic foraminifera in the Arctic: potentials and issues regarding modern and quaternary populations

    Energy Technology Data Exchange (ETDEWEB)

    Eynaud, Frederique, E-mail: f.eynaud@epoc.u-bordeaux1.fr [Universite Bordeaux I, Laboratoire EPOC (Environnements et Paleoenvironnements OCeaniques), UMR CNRS 5805, Avenue des facultes, 33405 Talence cedex - France (France)

    2011-05-15

    Calcareous microfossils are widely used by paleoceanographers to investigate past sea-surface hydrology. Among these microfossils, planktonic foraminifera are probably the most extensively used tool (e.g. [1] for a review), as they are easy to extract from the sediment and can also be used for coupled geochemical (e.g; {delta}{sup 18}O, {delta}{sup 13}C, Mg/Ca) and paleo-ecological investigations. Planktonic foraminifera are marine protists, which build a calcareous shell made of several chambers which reflect in their chemistry the properties of the ambient water-masses. Planktonic foraminifera are known to thrive in various habitats, distributed not only along a latitudinal gradient, but also along different water-depth intervals within surface waters (0-1000 m). Regarding their biogeographical distribution, planktonic foraminifera assemblages therefore mirror different water-masses properties, such as temperature, salinity and nutrient content of the surface water in which they live. The investigation of the specific composition of a fossil assemblage (relative abundances) is therefore a way to empirically obtain (paleo)information on past variations of sea-surface hydrological parameters. This paper focuses on the planktonic foraminifera record from the Arctic domain. This polar region records peculiar sea-surface conditions, with the influence of nearly perennial sea-ice cover development. This has strong impact on living foraminifera populations and on the preservation of their shells in the underlying sediments.

  11. Effect of varying frontal systems on stable oxygen and carbon isotopic compositions of modern planktic foraminifera of Southern Ocean

    Digital Repository Service at National Institute of Oceanography (India)

    Tiwari, M.; Mohan, R.; Meloth, T.; Naik, S.S.; Sudhakar, M.

    , sediment cores and other physi- cal oceanographic parameters were collected. Here, we present the isotopic results obtained from planktic foraminifera from the plankton net samples and sur- face sediments. We find that, in this region too, plank- tic... characteristics in the Indian sector of the Southern Ocean. The δ 18 O value of planktic foraminifera is mainly governed by SST fluctuations: the samples be- come isotopically heavier polewards. Further, the plank- tic foraminifera appear to secrete...

  12. Hydrodynamic bearings

    CERN Document Server

    Bonneau, Dominique; Souchet, Dominique

    2014-01-01

    This Series provides the necessary elements to the development and validation of numerical prediction models for hydrodynamic bearings. This book describes the rheological models and the equations of lubrication. It also presents the numerical approaches used to solve the above equations by finite differences, finite volumes and finite elements methods.

  13. Foraminifera and Thecamoebians as hydrodynamic indicators for Amazon estuarine system

    Science.gov (United States)

    Laut, L. L.; Figueiredo, A. G.; Santos, V. F.; Souza-Vieira, S.

    2007-05-01

    The Amazon mangrove forest in Brazilian territory is one of the most extended in the world. It goes from Ponta do Tubarao (4S e 43W) to Cape Orange (5N e 51W) along 2,250 km of coast line. Because the Amazon River System influence, it can be divided into two regions; one with river influence toward north and the other without river influence. In order to characterize the mangrove environment hydrodynamic on both sides of the Amazon River System, foraminifera and thecamoebians assemblages were investigated in the sediment of two estuaries; Araguari to the North (1 15S - 50 30W) and Caete to the South (0 50S - 46 30W). For both estuaries forams and thecamoebians species distribution are atypical relative to other world regions. In both, there are only few calcareous forams and almost all are small and possible of being transported in suspension. Typical estuarine species were not identified. The typical mangrove forams which are agglutinated species were dominant in both estuaries. However, the Caete estuary has a large number of forams species (29), indicating better efficiency in mixing fresh and salt water in comparison to the Araguari. On the other hand, the Araguari has big richness of thecamoebians species (15) indicating fresh water prevalence. The fresh water predominance is due to the Amazon water plume being diverted to the Amapa coast where the Araguari estuary is located. The foraminifera species was also used to determine the salt water penetration in the estuary. In the Caete estuary, salt water penetrates to about 40 km while in the Araguari it does coincide with the limit of the bore tide wave "pororoca" penetration, 45 km. Based on the species succession (forams to thecamoebians species) the Araguary estuary can be divided into three regions controlled by turbidity: the outer, middle and inner estuary. The Caete species succession is not that clear and only could be divided based on salinity into outer and inner estuary. In both estuaries forams and

  14. Bearing structures

    International Nuclear Information System (INIS)

    Lee, A.S.; Preece, G.E.

    1988-01-01

    A hydrostatic bearing for the lower end of the vertical shaft of a sodium pump comprises a support shell encircling the shaft and a bush located between the shell and shaft. Liquid sodium is fed from the pump outlet to the bush/shaft and bush/shell interfaces to provide hydrostatic support. The bush outer surface and the shell inner surface are of complementary part-spherical shape and the bush floats relative to the shaft so that the bush can align itself with the shaft axis. Monitoring of the relative rotational speed of the bush with respect to the shaft (such rotation being induced by the viscous drag forces present) is also performed for the purposes of detecting abnormal operation of the bearing or partial seizure, at least one magnet is rotatable with the bush, and a magnetic sensor provides an output having a frequency related to the speed of the bush. (author)

  15. Ecological tolerances of Miocene larger benthic foraminifera from Indonesia

    Science.gov (United States)

    Novak, Vibor; Renema, Willem

    2018-01-01

    To provide a comprehensive palaeoenvironmental reconstruction based on larger benthic foraminifera (LBF), a quantitative analysis of their assemblage composition is needed. Besides microfacies analysis which includes environmental preferences of foraminiferal taxa, statistical analyses should also be employed. Therefore, detrended correspondence analysis and cluster analysis were performed on relative abundance data of identified LBF assemblages deposited in mixed carbonate-siliciclastic (MCS) systems and blue-water (BW) settings. Studied MCS system localities include ten sections from the central part of the Kutai Basin in East Kalimantan, ranging from late Burdigalian to Serravallian age. The BW samples were collected from eleven sections of the Bulu Formation on Central Java, dated as Serravallian. Results from detrended correspondence analysis reveal significant differences between these two environmental settings. Cluster analysis produced five clusters of samples; clusters 1 and 2 comprise dominantly MCS samples, clusters 3 and 4 with dominance of BW samples, and cluster 5 showing a mixed composition with both MCS and BW samples. The results of cluster analysis were afterwards subjected to indicator species analysis resulting in the interpretation that generated three groups among LBF taxa: typical assemblage indicators, regularly occurring taxa and rare taxa. By interpreting the results of detrended correspondence analysis, cluster analysis and indicator species analysis, along with environmental preferences of identified LBF taxa, a palaeoenvironmental model is proposed for the distribution of LBF in Miocene MCS systems and adjacent BW settings of Indonesia.

  16. Journal Bearings

    Directory of Open Access Journals (Sweden)

    Renato Brancati

    1999-01-01

    determined after acquiring and analysing the orbits described by the journal axis for assigned unbalance values in different operating conditions. Analysis of the results shows some particular operating features that were not entirely predicted by the theoretical model and which may give rise to malfunctions in the rotor-tilting pad bearings system. The tests were carried out in the rotor dynamics laboratory of the Dipartimento di Ingegneria Meccanica per l'Energetica at the University of Naples.

  17. Camshaft bearing arrangement

    Energy Technology Data Exchange (ETDEWEB)

    Aoi, K.; Ozawa, T.

    1986-06-10

    A bearing arrangement is described for the camshaft of an internal combustion engine or the like which camshaft is formed along its length in axial order with a first bearing surface, a first cam lobe, a second bearing surface, a second cam lobe, a third bearing surface, a third cam lobe and a fourth bearing surface, the improvement comprising first bearing means extending around substantially the full circumference of the first bearing surface and journaling the first bearing surface, second bearing means extending around substantially less than the circumference of the second bearing surface and journaling the second bearing surface, third bearing means extending around substantially less than the circumference of the third bearing surface and journaling the third bearing surface, and fourth bearing means extending around substantially the full circumference of the fourth bearing surface and journaling the first bearing surface.

  18. Recent benthic foraminifera assemblages from mangrove swamp and channels of Abu Dhabi (UAE)

    Science.gov (United States)

    Fiorini, Flavia; Lokier, Stephen W.; Odeh, Weaam A. S. Al; Paul, Andreas; Song, Jianfeng; Freeman, Mark; Michel, Françoise

    2017-04-01

    Zonation of Recent mangrove environments can be defined using benthic foraminifera, however, little is known about foraminifera from mangrove environments of the Persian/Arabian Gulf. The objective of this study is to produce a detailed micropaleontological and sedimentological analysis to identify foraminiferal associations from mangrove swamps and channels located on the eastern side of Abu Dhabi Island (UAE). Detailed sediment sampling collection in mangal environments of Eastern Abu Dhabi was carried out to assess the distribution of benthic foraminifera in different sedimentary facies in the mangal and in the surrounding natural environments of the upper and lower intertidal area (mud flats and channels). A 100 m transect across a natural channel in a mangal on the eastern side of Abu Dhabi Island was sampled in detail for sedimentological and foraminiferal analysis. Forty-seven samples were collected at 2 meter intervals along the transect in a number of different sedimentary facies including; fine sediment in areas exposed during low tide and close to mangrove trees (Avicennia marina), fine sediment rich in leaf material, coarse sediment in channels, and coarse sediments with a shell lag. At each sampling location environmental parameters were recorded, including water depth, salinity, temperature and pH. Samples collected for foraminiferal analysis were stained in rose Bengal in order to identify living specimens. Samples collected on the mud flat at the margin of the channel show a living foraminiferal assemblage characterised by abundant foraminifera belonging to the genera Ammonia, Elphidium, Cribroelphidium, Triloculina, Quinqueloculina, Sigmoilinita, Spiroloculina, Peneroplis and Spirolina. Samples collected in the lower (wet) intertidal area close to Avicennia marina roots, presented a low-diversity assemblage mostly comprising small-sized opportunistic foraminifera of the genera Ammonia and Cribroelphidium along with rare Triloculina and

  19. Geochemistry of trace elements and Sr- Nd isotopes of foraminifera shell from the Okinawa Trough

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Trace elemental associations and Sr - Nd isotopic compositions are of important to recognition of biogenic material from mixed marine sediments. The foraminifera shell from the Okinawa Trough strongly enrichesSr, P, Mn andBa, enriches Li, U, Th, Sc, Co, Cu, Pb, Zn, Cr, Rb, Y, Sb and light rare earth elements, slightly enriches V, Ga, Zr, Nb, Cd and middle rare earth elements,is short of Mo, In, Sn, Cs, Hf, Ta, W, Ti, Bi and heavy rare earth elements. The mechanism of elemental enrichment in forminifera is the concentrations of trace elements in sea water and selective absorption of trace elements during foraminifera living, as well as the geochemical affinity between major elements and trace elements. The REE (rare earth elements) partition pattern of foraminifera shell of the Okinawa Trough shows enrichment of middle rare earth elements with slightly negative Ce anomaly,which are different from those of foraminifera of the Pacific Ocean. The Sr, Nd isotopic ratios of the Okinawa Trough foraminifera are 0.709 769 and 0.512 162, respectively, which are different not only from those of oceanic water, but also from those of river water of China's Mainland, the former is slightly higher than those of oceanic water, but much lower than those of river water; the latter is slightly lower than those of oceanic water, but higher than those of river water, demonstrating that the Okinawa Trough sea water has been influenced by river water of China's Mainland.

  20. Presence of Foraminifera of Superfamily Komokioidea (Order Astrorhizida) in Colombian deep Caribbean waters.

    Science.gov (United States)

    Tavera-Martínez, Laura; Marchant, Margarita

    2017-10-20

    Research regarding deep-sea benthic foraminifera in the Colombian Caribbean requires further development given the complete lack of information related to the different groups that constitute associations and the ecological functions they fulfill. For this purpose, a taxonomic description of Superfamily Komokioidea was composed from macrofauna samples from between 1,215 m and 3,179 m depth, obtained during the research cruise ANH-COL 4 and COL 5 carried out in 2014. Results showed foraminifera belonging to the three families: Komokiidae, Baculellidae, and Normaninidae, inclu-ding five genera (Lana, Komokia, Ipoa, Normaninam, and Catena) and five species (Lana neglecta, Komokia multiramosa, Normanina conferta, Ipoa fragila, and Catena piriformis). This study presents knowledge regarding deep-sea Colombian Caribbean benthic foraminifera, which to date have not been recorded from this region. Their depth distribution when compared with other studies from the Atlantic and Pacific, allows the expansion of taxonomic inventories and the characterization of biodiversity within poorly explored regions.

  1. Three dimensional morphological studies of Larger Benthic Foraminifera at the population level using micro computed tomography

    Science.gov (United States)

    Kinoshita, Shunichi; Eder, Wolfgang; Woeger, Julia; Hohenegger, Johann; Briguglio, Antonino; Ferrandez-Canadell, Carles

    2015-04-01

    Symbiont-bearing larger benthic Foraminifera (LBF) are long-living marine (at least 1 year), single-celled organisms with complex calcium carbonate shells. Their morphology has been intensively studied since the middle of the nineteenth century. This led to a broad spectrum of taxonomic results, important from biostratigraphy to ecology in shallow water tropical to warm temperate marine palaeo-environments. However, it was necessary for the traditional investigation methods to cut or destruct specimens for analysing the taxonomically important inner structures. X-ray micro-computed tomography (microCT) is one of the newest techniques used in morphological studies. The greatest advantage is the non-destructive acquisition of inner structures. Furthermore, the running improve of microCT scanners' hard- and software provides high resolution and short time scans well-suited for LBF. Three-dimensional imaging techniques allow to select and extract each chamber and to measure easily its volume, surface and several form parameters used for morphometric analyses. Thus, 3-dimensional visualisation of LBF-tests is a very big step forward from traditional morphology based on 2-dimensional data. The quantification of chamber form is a great opportunity to tackle LBF structures, architectures and the bauplan geometry. The micrometric digital resolution is the only way to solve many controversies in phylogeny and evolutionary trends of LBF. For the present study we used micro-computed tomography to easily investigate the chamber number of every specimen from statistically representative part of populations to estimate population dynamics. Samples of living individuals are collected at monthly intervals from fixed locations. Specific preparation allows to scan up to 35 specimens per scan within 2 hours and to obtain the complete digital dataset for each specimen of the population. MicroCT enables thus a fast and precise count of all chambers built by the foraminifer from its

  2. Pre-monsoon living planktonic foraminifera from the Southeastern Arabian Sea

    Digital Repository Service at National Institute of Oceanography (India)

    Guptha, M.V.S.; Naidu, P.D.; Muralinath, A.S.

    LOGICAL SoCIETY OF INDIA Vol. 36, Dec. 1990, pp. 654 to 660 Pre-Monsoon Living Planktonic Foraminifera from the Southeastern Arabian Sea M. V. S. GUPTHA.. P. DIVAKAR NAlDU AND A. S. MURALINATH Nalional Institute of Oceanography, Dona Paula, Goa 403004...

  3. A Record of Rotaloid Foraminifera from the Upper Permian-Lower ...

    African Journals Online (AJOL)

    PRABHAS PANDE

    INTRODUCTION. In the history of organic evolution, the end of Palaeozoic Era was marked by the conspicuous event of mass extinctions. Amongst foraminifera, as many as fourteen families became extinct. (Loeblich and Tappan, 1964) during the Permian Period and many new families evolved in the. Mesozoic. There is a ...

  4. Foraminifera as climatic indicators in the sediments of Western Indian continental shelf

    Digital Repository Service at National Institute of Oceanography (India)

    Setty, M.G.A.P.

    to tell, which can be unravelled by careful analysis and interpretation. Foraminifera are primarily of two kinds-planktonic and benthonic-each having a significant role to play. Therefore, in the study of a sample, the planktonic and benthonic populations...

  5. Paleoecology of benthic foraminifera from the Miocene of the San Jacinto Basin, Colombia

    Science.gov (United States)

    Poveda, John Sebastian; Fiorini, Flavia; Andres Trejos, Raul; Vallejo, Diego Felipe; Pardo, Andres

    2015-04-01

    Quantitative benthic foraminifera analysis was conducted on 34 samples collected from a borehole core (393.72m deep) drilled by Colombian Hydrocarbon Agency (ANH) on 2009 in the San Jacinto basin (Northern Colombia). The aims of the research were to define a taxonomical data-bank of Miocene benthic foraminifera for this region, to use the benthic foraminifera assemblages to interpret the paleoenvironment and to identify paleoenvironmental changes. The bottom of the section was dated between lowest Burdigalian to middle Langhian (20.393-17.721 Ma) based on calcareous nannofossils bioevents: LO Helicosphaera ampliaperta, HCO Sphenolithus belemnos and LCO Sphenolithus heteromorphus. The benthic foraminifera fauna identified in the studied samples is composed for the majority of calcareous hyaline tests and is dominated by infaunal taxas. Species belonging to the genera Uvigerina and Lenticulina are commonly occurring in the studied section together with other species typical of outer-shelf upper-bathyal environment. Cibicidoides spp., abundant in the lower part of the section, abruptly decreases in abundance in the upper part. Species belonging to the opportunistic genera Bulimina and Bolivina are more abundant in the upper part of the section. Variability in the abundance of opportunistic species can be associated with tectonic disturbance on the Sinu-San Jacinto fold belt (NW of Colombia) as a result of collision of the Caribbean plate against NW of South America. The tectonics could lead a perturbation on deep ocean sedimentation and circulation.

  6. Living planktonic foraminifera during the late summer monsoon period in the Arabian Sea

    Digital Repository Service at National Institute of Oceanography (India)

    Guptha, M.V.S.; Mohan, R.; Muralinath, A.S.

    with deepening of the mixed layer, since this species preferentially dwells in nutrient-rich upwelling waters. The population density of planktonic foraminifera ranges between 31 and 185 specimens per 10@u-3@@m@u3@@. The low absolute numbers of planktonic...

  7. Effect of carbonate ion concentration and irradiance on calcification in planktonic foraminifera

    DEFF Research Database (Denmark)

    Lombard, Fabien; da Rocha, R. E.; Bijma, J.

    2010-01-01

    rates of these two species are projected to be 6 to 13% lower than the present conditions, while the final shell weights are reduced by 20 to 27% for O. universa and by 4 to 6% for G. sacculifer. These results indicate that ocean acidification would impact on calcite production by foraminifera and may...

  8. The Foraminifera of the Saba Bank Expedition, 1972 (Cicar Cruises 34, 35)

    NARCIS (Netherlands)

    Hofker, J.

    1980-01-01

    INTRODUCTION Bottom samples obtained by means of a Van Veen grab during the 1972 Saba Bank Expedition (CICAR cruises 34 and 35) appeared to comprise many samples with Foraminifera. This material was kindly put at my disposal by Dr. D. van Harten of the Geological Institute of the University of

  9. Morphological deformities of benthic foraminifera in response to nearshore pollution of the Red Sea, Egypt.

    Science.gov (United States)

    El-Kahawy, R; El-Shafeiy, M; Helal, S A; Aboul-Ela, N; El-Wahab, M Abd

    2018-04-28

    The Red Sea encompasses a wide range of tropical marine habitats that are stressed due to anthropogenic activities. The main anthropogenic activities are hydrocarbon exploration and important trading harbors. This work aims to assess the influence of the Red Sea coastal heavy metal contamination on the marine meiofauna along three sites (Ras Gharib, Safaga, and Quseir). Eight heavy metal (Cu, Cd, Zn, Pb, Cr, Co, Ni, and Mn) contents are considered in four benthic foraminiferal species (Elphidium striatopunctatum, Amphistegina lobifera, Amphisorus hemprichii, and Ammonia beccarii). Quseir Harbor showed the highest level of pollution followed by Safaga and Ras Gharib sites. The analyzed benthic foraminiferal tests displayed noteworthy high concentrations of Cd, Zn, and Pb in Quseir Harbor which could be attributed to the anthropogenic activities in the nearshore areas. Some foraminiferal tests exhibited abnormalities in their apertures, coiling, and shape of chambers. A comparison between normal and deformed foraminiferal tests revealed that the deformed ones are highly contaminated with elevated heavy metal contents such as Fe, Mn, Ni, and Cd. Statistics in addition to geo-accumulation and pollution load indices reveal a whistling alarm for the Quseir harbor. The present data are necessary to improve conservation and management of the Red Sea ecosystem in the near future.

  10. Regional variations in the fluxes of foraminifera carbonate, coccolithophorid carbonate and biogenic opal in the northern Indian Ocean

    Digital Repository Service at National Institute of Oceanography (India)

    Ramaswamy, V.; Gaye, B.

    Mass fluxes of diatom opal, planktonic foraminifera carbonate and coccolithophorid carbonate were measured with time-series sediment traps at six sites in the Arabian Sea, Bay of Bengal and Equatorial Indian Ocean (EIOT). The above fluxes were...

  11. Distribution of planktonic foraminifera in waters of the submarine coral banks in southeast Arabian Sea during winter

    Digital Repository Service at National Institute of Oceanography (India)

    Rao, K.K.; Jayalakshmy, K.V.; Balasubramanian, T.

    Twentyfive species of planktonic foraminifera are recorded from 36 plankton tows collected from waters of the submerged coral banks- Bassas de Pedro, Sesostris and Cora Divh-located at northern end of the Laccadive group of islands in southeastern...

  12. Benthic foraminifera distribution in high polluted sediments from Niterói Harbor (Guanabara Bay), Rio de Janeiro, Brazil

    OpenAIRE

    Claudia G. Vilela; Daniele S. Batista; José A. Batista-Neto; Mirian Crapez; John J. Mcallister

    2004-01-01

    Dockyards and harbors are recognized as being important locations where sediment-associated pollutants can accumulate, which constitutes an environmental risk to aquatic life due to potential uptake and accumulation of heavy metals in the biota. The aim of this paper is to assess the concentrations and the effects of some heavy metals in the benthic foraminifera assemblage in Niterói Harbor. Low concentrations in the benthic foraminifera as well as the dominance of indicative species such as ...

  13. Distribution of living larger benthic foraminifera in littoral environments of the United Arab Emirates

    Science.gov (United States)

    Fiorini, Flavia; Lokier, Stephen W.

    2015-04-01

    The distribution of larger benthic foraminifera in Recent littoral environment of the United Arab Emirates (Abu Dhabi and Western regions) was investigated with the aim of understanding the response of those foraminifera to an increase in water salinity. For this purpose, 100 sediment samples from nearshore shelf, beach-front, channel, lagoon, and intertidal environment were collected. Sampling was undertaken at a water depth shallower than 15 m in water with a temperature of 22 to 35˚C, a salinity ranging from 40 to 60‰ and a pH of 8. Samples were stained with rose Bengal at the moment of sample collection in order to identify living specimens. The most abundant epiphytic larger benthic foraminifera in the studied area were Peneroplis pertusus and P. planatus with less common Spirolina areatina, S. aciculate and Sorites marginalis. The living specimens of the above mentioned species with normal test growing were particularly abundant in the nearshore shelf and lagoonal samples collected on seaweed. Dead specimens were concentrated in the coarser sediments of the beach-front, probably transported from nearby environments. Shallow coastal ponds are located in the upper intertidal zone and have a maximum salinity of 60‰ and contain abundant detached seagrass. Samples collected from these ponds possess a living foraminifera assemblage dominated by Peneroplis pertusus and P. planatus. High percentages (up to 50% of the stained assemblage) of Peneroplis presented abnormality in test growth, such as the presence of multiple apertures with reduced size, deformation in the general shape of the test, irregular suture lines and abnormal coiling. The high percentage of abnormal tests reflects natural environmental stress mainly caused by high and variable salinity. The unique presence of living epiphytic species, suggests that epiphytic foraminifera may be transported into the pond together with seagrass and continued to live in the pond. This hypothesis is supported by

  14. Benthic foraminifera in the plankton following storms: what does this mean for (palaeo)-ecological interpretations?

    Science.gov (United States)

    Hart, Malcolm; Molina, Giulia; Smart, Christopher; Widdicombe, Claire

    2017-04-01

    The Western Channel Observatory was established by the Natural Environment Research Council (NERC), with Plymouth Marine Laboratory managing the two autonomous buoys that are located to the south of Plymouth in the English Channel (Stations L4 and E1): see Smyth et al. (2015). These two locations are now monitored continually and there is regular sampling of the water column and the sea floor at both locations. At Station L4, despite being in waters with a depth of 50 m, benthic foraminifera are regularly found in the surface water plankton samples. Some of these benthic foraminifera contain algal symbionts, indicating that they may be living at the time of capture. If benthic foraminifera can be entrained in the water column, while still living, then this provides a mechanism for 'migration' that is much more rapid and efficient than the rate at which protists could migrate within, or on, the sediment surface. Recolonization by foraminifera, following disturbance, could well be facilitated by this mechanism which has only rarely been reported in the literature (e.g., Murray, 1965). It is clearly limited to depths impacted by fair weather ( 30 m) or storm wave base (80 - 100 m). Data gathered during winter 2015-2016 certainly indicate that, following storm events, the larger the number of benthic foraminifera in the plankton tows and the greater their overall size. Some of the individuals being observed appear to contain sediment, indicating that they have been picked up from the sediment surface and, despite their greater weight, have still been transported into the plankton. Using data from the nearby sea area, off-shore and within Plymouth Sound, we are trying to ascertain if the recorded assemblage is from the L4 area, or whether they have been transported out from shallower-water environments, possibly assisted by increased run-off caused by heavy rainfall (associated with the storms). Clearly, re-distribution of foraminifera in the environment might make

  15. REKONSTRUKSI BATIMETRI DAN IKLIM PURBA BERDASARKAN FORAMINIFERA DAERAH RALLA BARRU, SULAWESI SELATAN INDONESIA

    Directory of Open Access Journals (Sweden)

    Meutia Farida

    2017-10-01

    Full Text Available Daerah Ralla terletak di Kabupaten Barru Provinsi Sulawesi Selatan, tersusun atas batuan karbonat dan vulkanik. Salah satu komponen utama penyusun batuan ini adalah kandungan fosil foraminifera baik planktonik maupun bentonik yang jumlahnya melimpah. Penentuan umur dan lingkungan pengendapan purba (paleobathymetry, menggunakan foraminifera sebagai proksi iklim purba (paleoclimate yang baik. Pengambilan sampel dilakukan dengan metode Penampang Stratigrafi Terukur (Measuring Section pada singkapan napal dan batugamping dengan ketebalan mencapai 748,16 sentimeter yang terdiri dari 23 lapisan batuan. Hasil identifikasi dan determinasi fosil foraminifera menunjukkan bahwa pada sampel terdapat 46 spesies bentonik dan 28 spesies planktonik, dengan kisaran umur batuan adalah Eosen Bawah bagian atas (P9 – Eosen Tengah bagian tengah (P11, perubahan batimetri dengan siklus pengendapan inner neritic – upper bathyal - outer neritic. Jumlah spesies yang beragam dan sangat melimpah serta ukuran fosil yang besar menunjukkan nutrisi pada saat itu sangat berlimpah, dengan temperatur 0⁰– 27⁰C sebagai kondisi iklim hangat (warm water. Ralla area is located in Barru District, South Sulawesi Province which consisted of carbonate and volcanic rocks. One of the main components of these rocks is foraminifera fossils, include planktonic and bentonic which founded to be abundance. In determining the age and depositional environment (paleobathymetry, foraminifera fossils could be used as a good paleoclimate proxy. The research was conducted by Stratigraphy Measured (Measuring Section method in marl and limestone outcrop with a thickness of up to 748.16 centimeters which consists of 23 rock layers. Identification and determination of foraminifera fossils suggests that there are 46 bentonic and 28 planktonic species on samples, which are estimated the age of the rocks range from the end of lower Eocene (P9 till the middle of Middle Eocene (P11, bathymetry changes

  16. Passive magnetic bearing configurations

    Science.gov (United States)

    Post, Richard F [Walnut Creek, CA

    2011-01-25

    A journal bearing provides vertical and radial stability to a rotor of a passive magnetic bearing system when the rotor is not rotating and when it is rotating. In the passive magnetic bearing system, the rotor has a vertical axis of rotation. Without the journal bearing, the rotor is vertically and radially unstable when stationary, and is vertically stable and radially unstable when rotating.

  17. Morphological changes during the ontogeny of Velapertina indigena (Foraminifera) from the Transylvanian Basin (Romania)

    International Nuclear Information System (INIS)

    Kiss, P.; Ruman, A.; Hudackova, N.; Hermanova, Z

    2017-01-01

    Species Velapertina indigena (Luczkowska, 1955) represents common Upper Badenian planktonic foraminifera in the Western Carpathians region. Correct taxonomic determination is often precluded by the complicated ontogenetic evolution resulted into several distinguished morphological stages. In this study the inner shell structures were observed by using tomographic microscope to identify five ontogenetic stages (sensu Brummer). General morphological features of the shell, such as the chamber shape and number, the aperture position and character, the wall texture, and the chambers coiling direction were documented for each stage. The reconstructed ontogenetic model, composed of five ontogenetic stages, was correlated with the 'five stage concept' of Globigerinoides sacculifer. Our study shows potential of the tomographic microscope visualization in improvement of the correct taxonomic classification of non-adult individuals as well as the foraminifera trophic mechanisms interpretation. (authors)

  18. Decalcification of benthic foraminifera due to "Hebei Spirit" oil spill, Korea.

    Science.gov (United States)

    Lee, Yeon Gyu; Kim, Shin; Jeong, Da Un; Lee, Jung Sick; Woo, Han Jun; Park, Min Woo; Kim, Byeong Hak; Son, Maeng Hyun; Choi, Yang Ho

    2014-10-15

    In order to determine the effects on foraminifera due to spilled crude oil in the "Herbei Spirit" incident, a study of benthic foraminiferal assemblages was carried out on sediment samples collected from the Sogeunri tidal flat, Taean Peninsula, Korea. Breakages of the chambers in the Ammonia beccarii and Elphidium subincertum species of the Sogeunri tidal flat with a low pH (6.98 on average) were marked. These chamber breakages occurred in 71.6% of A. beccarii and are thought to be caused by decalcification due to the fall in pH resulting from the "Hebei Spirit" oil spill. The factors that affect breakage of the chamber in benthic foraminifera under low pH condition may be not only deto decalcification but also to exposure duration of substrata in the tidal flat spilled crude oil. Copyright © 2014 Elsevier Ltd. All rights reserved.

  19. Recent benthic foraminifera and sedimentary facies distribution of the Abu Dhabi (United Arab Emirates) coastline

    Science.gov (United States)

    Fiorini, Flavia; Lokier, Stephen W.

    2014-05-01

    The distribution of benthic foraminifera and sedimentary facies from Recent coastline environments adjacent to the coastline of Abu Dhabi (UAE) was studied in detail with the aim to: 1) provide reliable analogs for understanding and interpreting the depositional environment of ancient shallow-marine sediments from the UAE; 2) assess any modifications in the distribution of benthic environments and sedimentary facies in an area affected by significant anthropogenic activities - particular construction and land reclamation. A total of 100 sea-floor sediment samples were collected in different shallow-marine sedimentary environments (nearshore shelf, beach-front, channels, ooid shoals, lagoon and mangals) close to the coastline of Abu Dhabi Island. Where possible, we revisited the sampling sites used in several studies conducted in the middle of last century (prior to any significant anthropogenic activities) to assess temporal changes in Recent benthic foraminifera and sedimentary facies distribution during the last 50 years. Five foraminiferal assemblages were recognized in the studied area. Species with a porcellaneous test mainly belonging to the genera Quinqueloculina, Triloculina, Spiroloculina, Sigmoilinita are common in all studied areas. Larger benthic foraminifera Peneroplis and Spirolina are particularly abundant in samples collected on seaweed. Hyaline foraminifera mostly belonging to the genera Elphidium, Ammonia, Bolivina and Rosalina are also common together with Miliolidae in the nearshore shelf and beach front. Agglutinated foraminifera (Clavulina, Textularia, Ammobaculites and Reophax) are present in low percentages. The species belonging to the genera Ammobaculites and Reophax are present only in the finest grain samples particularly in lagoons and mangal environments and have not been reported previously in the studied area. The majority of the ooid shoal sediments, the coarser sediments of the beach-front and samples collected in dredged channels

  20. Foraminifera Population from South Africa Coast Line (Indian and Atlantic Oceans

    Directory of Open Access Journals (Sweden)

    Engin Meriç

    2014-11-01

    Full Text Available Cape Town is the second-largest city of the Republic of South Africa. Research is conducted in 3 different stations: Maori Bay, which lies in the southwest of Cape Town, and Pyramid Rock and Partridge Points which lies in the False Bay, southeast part of Cape Town. Samples are taken from young sediments at 10.00 and 20.00 m depths, and collected by scuba-diving method. The aim of the study is to investigate the living benthic foraminifera assemblages in the Atlantic Ocean, and to compare these assemblages with the southeastern part of the Atlantic Ocean, the Arabian Sea, Indian Ocean and Western Pacific assemblages. Moreover, the aim of the study is to determine whether there are any benthic foraminifera forms reaching to the Mediterranean from Pacific Ocean, Indian Ocean or Red Sea via Suez Channel.

  1. Vertical distribution and isotopic composition of living planktonic foraminifera in the western North Atlantic

    International Nuclear Information System (INIS)

    Fairbanks, R.G.; Wiebe, P.H.; Be, A.W.H.

    1980-01-01

    Thirteen species of planktonic foraminifera collected with vertically stratified zooplankton tows in the slope water, Gulf Stream cold core ring, and northern Sargasso Sea show significant differences in their vertical distributions in the upper 200 meters of these different hydrographic regimes. Gulf Stream cold core rings may be responsible for a southern displacement of the faunal boundary associated with the Gulf Stream when reconstructed from the deep-sea sediment record. Oxygen isotope analyses of seven species reveal that nonspinose species (algal symbiont-barren) apparently calcify in oxygen isotope equilibrium, whereas spinose species usually calcify out of oxygen isotope equilibrium by approximately -0.3 to -0.4 per mil in delta 18 O values. The isotope data indicate that foraminifera shells calcify in depth zones that are significantly narrower than the overall vertical distribution of a species would imply

  2. Foraminifera [Marine Microfossil] as an additional tool for archaeologists - Examples from the Arabian Sea

    Digital Repository Service at National Institute of Oceanography (India)

    Nigam, R.

    or- ganisms, their presence and absence could be a deci- GLIMPSES OF MARINE ARCHAEOLOGY IN INDIA sive factor in interpreting whether any ancient water body was filled with fresh or marine (brackish) water. With this intention, the author has..., a conceptual model (Figure 4) was provided and techniques were developed for use of foraminifera as a proxy to determine the paleomonsoons. Studies on core samples off Karwar (Figure 5), west coast of India showed the clear signals of marked...

  3. Living benthic Foraminifera from the Saquarema lagoonal system (Rio de Janeiro, southeastern Brazil)

    OpenAIRE

    Belart, Pierre; Laut, Vanessa; Clemente, Iara; Raposo, Débora; Martins, Virgínia; Frontalini, Fabrizio; Lorini, Maria; Fortes, Rafael; Laut, Lazaro

    2017-01-01

    Transitional environments such as coastal lagoons with narrow connections to the sea are ecosystems very sensitive to natural or anthropogenic pressures. They are biodiversity hotspots and for this reason it should be studied and preserved. This study lists the benthic Foraminifera species from the Saquarema lagoonal system (SLS), Rio de Janeiro state, Brazil. This complex ecosystem consists of four large connected lagoons, namely Urussanga, Jardim, Boqueirão, and Saquarema. A poorly diversif...

  4. Planktonic Foraminifera Proxies Calibration Off the NW Iberian Margin: Nutrients Approach

    Science.gov (United States)

    Salgueiro, E.; Castro, C. G.; Zuniga, D.; Martin, P. A.; Groeneveld, J.; de la Granda, F.; Villaceiros-Robineau, N.; Alonso-Perez, F.; Alberto, A.; Rodrigues, T.; Rufino, M. M.; Abrantes, F. F. G.; Voelker, A. H. L.

    2014-12-01

    Planktonic foraminifera (PF) shells preserved in marine sediments are a useful tool to reconstruct productivity conditions at different geological timescales. However, the accuracy of these paleoreconstructions depends on the data set and calibration quality. Several calibration works have been defining and improving the use of proxies for productivity and nutrient cycling parameters. Our contribution is centred on a multi-proxy calibration at a regional coastal upwelling system. To minimize the existing uncertainties affecting the use of trace elements and C stable isotopes as productivity proxy in the high productivity upwelling areas, we investigate the content and distribution of Ba/Ca and δ13C in the water column, its transference into the planktonic foraminifera shells, and, how the living planktonic foraminifera Ba/Ca and δ13C signal is related to the same planktonic foraminiferal species preserved in the sediment record. This study is based on a large data set from two stations (RAIA - 75m water depth, and CALIBERIA - 350m water depth) located off the NW Iberian margin (41.5-42.5ºN; 9-10ºW), and includes: i) two year monthly water column data (temperature, salinity, nutrients, chlorophyll a, Ba/Ca, and δ13C-DIC); ii) seasonal Ba/Ca, δ13C in several living PF species at both stations; and iii) Ba/Ca and δ13C in several PF species from a large set of core-top sediment samples in the study region. Additionally, total organic carbon and total alkenones were also measured in the sediment. Our results showed the link between productivity proxies in the surface sediment foraminifera assemblage and the processes regulating the actual phytoplankton dynamics in an upwelling area. The understanding of this relationship has special relevance since it gives fundamental information related to the past oceanic biogeochemistry and/or climate and improves the prevision of future changes against possible climate variability due to anthropogenic forcing.

  5. Addressing environmental issues through foraminifera – Case studies from the Arabian Sea

    Digital Repository Service at National Institute of Oceanography (India)

    Nigam, R.

    of relict foraminifera in certain environments also helps in deciphering palaeo-sea level conditions (Mazumder, 2004; Panchang et al., communicated). Significant Results: The relative rise and fall of sea level over the time has been studied with the help... and shared or distributed, contributing to balance the economy of the country during the time of crisis. Sufficient or excess rainfall conditions will even improve relationship between the states as well as bordering countries sharing water resources...

  6. Megalodon, mako shark and planktonic foraminifera from the continental shelf off Portugal and their age

    OpenAIRE

    ANTUNES, M.; LEGOINHA, P.; BALBINO, A.

    2015-01-01

    Turbidite fragments collected by a fishing net off the central Portuguese coast (Peniche) present some fossils. The matrix is phosphatized and iron-rich with small quantities of manganese, zinc and copper. The occurrence of Megaselachus megalodon most probably excludes an age older than Middle Miocene. Its very advanced evolution stage is consistent with a Pliocene age. Based on planktonic foraminifera in depressions of cetacean skulls recovered in the same way, from the same area...

  7. Time-response of cultured deep-sea benthic foraminifera to different algal diets

    Science.gov (United States)

    Heinz, P.; Hemleben, Ch; Kitazato, H.

    2002-03-01

    The vertical distribution of benthic foraminifera in the surface sediment is influenced by environmental factors, mainly by food and oxygen supply. An experiment of three different time series was performed to investigate the response of deep-sea benthic foraminifera to simulated phytodetritus pulses under stable oxygen concentrations. Each series was fed constantly with one distinct algal species in equivalent amounts. The temporal reactions of the benthic foraminifera with regard to the vertical distribution in the sediment, the total number, and the species composition were observed and compared within the three series. Additionally, oxygen contents and bacterial cell numbers were measured to ensure that these factors were invariable and did not influence foraminiferal communities. The addition of algae leads to higher population densities 21 days after food was added. Higher numbers of individuals were probably caused by higher organic levels, which in turn induced reproduction. A stronger response is found after feeding with Amphiprora sp. and Pyramimonas sp., compared to Dunaliella tertiolecta. At a constant high oxygen supply, no migration to upper layers was observed after food addition, and more individuals were found in deeper layers. The laboratory results thus agree with the predictions of the TROX-model. An epifaunal microhabitat preference was shown for Adercotryma glomerata. Hippocrepina sp. was spread over the entire sediment depth with a shallow infaunal maximum. Melonis barleeanum preferred a deeper infaunal habitat. Bacterial cell concentrations were stable during the laboratory experiments and showed no significant response to higher organic fluxes.

  8. Carbon isotopic fractionation in live benthic foraminifera -comparison with inorganic precipitate studies

    International Nuclear Information System (INIS)

    Grossmann, E.L.

    1984-01-01

    Carbon and oxygen isotopic analyses have been performed on live-stained aragonitic and calcitic benthic foraminifera and dissolved inorganic carbon from the Southern California Borderland to examine carbon isotopic fractionation in foraminifera. Temperature, salinity and pH data have also been collected to permit accurate determination of the delta 13 C of bicarbonate ion and thus aragonite-HCO 3 - and calcite-HCO 3 - isotopic enrichment factors (epsilonsub(ar-b) and epsilonsub(cl-b), respectively). Only species which precipitate in 18 O equilibrium have been considered. epsilonsub (ar-b) values based on Hoeglundina elegans range from 1.9 per mille at 2.7 deg C to 1.1 per mille at 9.5 deg C. The temperature dependence of epsilonsub(ar-b) is considerably greater than the equilibrium equation would predict and may be due to a vital effect. The calcitic foraminifera Cassidulina tortuosa, Cassidulina braziliensis, and Cassidulina limbata, Bank and Terrace dwellers, have similar delta 13 C values and yield an average epsilonsub(cl-b) value of -0.2 +- 0.1 per mille between 8 deg and 10 deg C. Calcitic Uvigerina curticosta, Uvigerina peregrina, and megalospheric B, argentea, Slope and Basin dwellers, are -0.7 +- 0.1 per mille enriched relative to ambient bicarbonate for 3 to 9 deg C. (author)

  9. Surface ocean metabarcoding confirms limited diversity in planktonic foraminifera but reveals unknown hyper-abundant lineages.

    Science.gov (United States)

    Morard, Raphaël; Garet-Delmas, Marie-José; Mahé, Frédéric; Romac, Sarah; Poulain, Julie; Kucera, Michal; de Vargas, Colomban

    2018-02-07

    Since the advent of DNA metabarcoding surveys, the planktonic realm is considered a treasure trove of diversity, inhabited by a small number of abundant taxa, and a hugely diverse and taxonomically uncharacterized consortium of rare species. Here we assess if the apparent underestimation of plankton diversity applies universally. We target planktonic foraminifera, a group of protists whose known morphological diversity is limited, taxonomically resolved and linked to ribosomal DNA barcodes. We generated a pyrosequencing dataset of ~100,000 partial 18S rRNA foraminiferal sequences from 32 size fractioned photic-zone plankton samples collected at 8 stations in the Indian and Atlantic Oceans during the Tara Oceans expedition (2009-2012). We identified 69 genetic types belonging to 41 morphotaxa in our metabarcoding dataset. The diversity saturated at local and regional scale as well as in the three size fractions and the two depths sampled indicating that the diversity of foraminifera is modest and finite. The large majority of the newly discovered lineages occur in the small size fraction, neglected by classical taxonomy. These unknown lineages dominate the bulk [>0.8 µm] size fraction, implying that a considerable part of the planktonic foraminifera community biomass has its origin in unknown lineages.

  10. Towards radiocarbon dating of single foraminifera with a gas ion source

    Science.gov (United States)

    Wacker, L.; Lippold, J.; Molnár, M.; Schulz, H.

    2013-01-01

    Carbonate shells from foraminifera are often analysed for radiocarbon to determine the age of deep-sea sediments or to assess radiocarbon reservoir ages. However, a single foraminiferal test typically contains only a few micrograms of carbon, while most laboratories require more than 100 μg for radiocarbon dating with an accelerator mass spectrometry (AMS) system. The collection of the required amount of foraminifera for a single analyses is therefore time consuming and not always possible. Here, we present a convenient method to measure the radiocarbon content of foraminifera using an AMS system fitted with a gas ion source. CO2 is liberated from 150 to 1150 μg of carbonate in septum sealed vials by acid decomposition of the carbonate. The CO2 is collected on a zeolite trap and subsequently transferred to a syringe from where it is delivered to the ion source. A sample of 400 μg (50 μg C) typically gives a 12C- ion source current of 10-15 μA over 20 min, yielding a measurement precision of less than 7 per mil for a modern sample. Using this method, we were able to date a single 560 μg Cibicides pseudoungerianus test at 14,030 ± 160 radiocarbon years. Only a minor modification to our existing gas handling system was required and the system is fully automatable to further reduce the effort involved for sample preparation.

  11. Towards radiocarbon dating of single foraminifera with a gas ion source

    International Nuclear Information System (INIS)

    Wacker, L.; Lippold, J.; Molnár, M.; Schulz, H.

    2013-01-01

    Carbonate shells from foraminifera are often analysed for radiocarbon to determine the age of deep-sea sediments or to assess radiocarbon reservoir ages. However, a single foraminiferal test typically contains only a few micrograms of carbon, while most laboratories require more than 100 μg for radiocarbon dating with an accelerator mass spectrometry (AMS) system. The collection of the required amount of foraminifera for a single analyses is therefore time consuming and not always possible. Here, we present a convenient method to measure the radiocarbon content of foraminifera using an AMS system fitted with a gas ion source. CO 2 is liberated from 150 to 1150 μg of carbonate in septum sealed vials by acid decomposition of the carbonate. The CO 2 is collected on a zeolite trap and subsequently transferred to a syringe from where it is delivered to the ion source. A sample of 400 μg (50 μg C) typically gives a 12 C − ion source current of 10–15 μA over 20 min, yielding a measurement precision of less than 7 per mil for a modern sample. Using this method, we were able to date a single 560 μg Cibicides pseudoungerianus test at 14,030 ± 160 radiocarbon years. Only a minor modification to our existing gas handling system was required and the system is fully automatable to further reduce the effort involved for sample preparation.

  12. Towards radiocarbon dating of single foraminifera with a gas ion source

    Energy Technology Data Exchange (ETDEWEB)

    Wacker, L., E-mail: wacker@phys.ethz.ch [Laboratory of Ion Beam Physics, ETH Zurich, 8093 Zurich (Switzerland); Lippold, J. [Heidelberg Academy of Sciences, 69120 Heidelberg (Germany); Molnar, M. [Laboratory of Ion Beam Physics, ETH Zurich, 8093 Zurich (Switzerland); Institute of Nuclear Research, Hungarian Academy of Sciences, 4026 Debrecen (Hungary); Schulz, H. [Institute for Geosciencies, University of Tuebingen, 72076 Tuebingen (Germany)

    2013-01-15

    Carbonate shells from foraminifera are often analysed for radiocarbon to determine the age of deep-sea sediments or to assess radiocarbon reservoir ages. However, a single foraminiferal test typically contains only a few micrograms of carbon, while most laboratories require more than 100 {mu}g for radiocarbon dating with an accelerator mass spectrometry (AMS) system. The collection of the required amount of foraminifera for a single analyses is therefore time consuming and not always possible. Here, we present a convenient method to measure the radiocarbon content of foraminifera using an AMS system fitted with a gas ion source. CO{sub 2} is liberated from 150 to 1150 {mu}g of carbonate in septum sealed vials by acid decomposition of the carbonate. The CO{sub 2} is collected on a zeolite trap and subsequently transferred to a syringe from where it is delivered to the ion source. A sample of 400 {mu}g (50 {mu}g C) typically gives a {sup 12}C{sup -} ion source current of 10-15 {mu}A over 20 min, yielding a measurement precision of less than 7 per mil for a modern sample. Using this method, we were able to date a single 560 {mu}g Cibicides pseudoungerianus test at 14,030 {+-} 160 radiocarbon years. Only a minor modification to our existing gas handling system was required and the system is fully automatable to further reduce the effort involved for sample preparation.

  13. Foraminifera Models to Interrogate Ostensible Proxy-Model Discrepancies During Late Pliocene

    Science.gov (United States)

    Jacobs, P.; Dowsett, H. J.; de Mutsert, K.

    2017-12-01

    Planktic foraminifera faunal assemblages have been used in the reconstruction of past oceanic states (e.g. the Last Glacial Maximum, the mid-Piacenzian Warm Period). However these reconstruction efforts have typically relied on inverse modeling using transfer functions or the modern analog technique, which by design seek to translate foraminifera into one or two target oceanic variables, primarily sea surface temperature (SST). These reconstructed SST data have then been used to test the performance of climate models, and discrepancies have been attributed to shortcomings in climate model processes and/or boundary conditions. More recently forward proxy models or proxy system models have been used to leverage the multivariate nature of proxy relationships to their environment, and to "bring models into proxy space". Here we construct ecological models of key planktic foraminifera taxa, calibrated and validated with World Ocean Atlas (WO13) oceanographic data. Multiple modeling methods (e.g. multilayer perceptron neural networks, Mahalanobis distance, logistic regression, and maximum entropy) are investigated to ensure robust results. The resulting models are then driven by a Late Pliocene climate model simulation with biogeochemical as well as temperature variables. Similarities and differences with previous model-proxy comparisons (e.g. PlioMIP) are discussed.

  14. Carbon isotopic fractionation in live benthic foraminifera -comparison with inorganic precipitate studies

    Energy Technology Data Exchange (ETDEWEB)

    Grossmann, E L [University of Southern California, Los Angeles (USA). Dept. of Geological Sciences

    1984-07-01

    Carbon and oxygen isotopic analyses have been performed on live-stained aragonitic and calcitic benthic foraminifera and dissolved inorganic carbon from the Southern California Borderland to examine carbon isotopic fractionation in foraminifera. Temperature, salinity and pH data have also been collected to permit accurate determination of the delta/sup 13/C of bicarbonate ion and thus aragonite-HCO/sub 3//sup -/ and calcite-HCO/sub 3//sup -/ isotopic enrichment factors (epsilonsub(ar-b) and epsilonsub(cl-b), respectively). Only species which precipitate in /sup 18/O equilibrium have been considered. epsilonsub (ar-b) values based on Hoeglundina elegans range from 1.9 per mille at 2.7 deg C to 1.1 per mille at 9.5 deg C. The temperature dependence of epsilonsub(ar-b) is considerably greater than the equilibrium equation would predict and may be due to a vital effect. The calcitic foraminifera Cassidulina tortuosa, Cassidulina braziliensis, and Cassidulina limbata, Bank and Terrace dwellers, have s

  15. Planktonic foraminifera-derived environmental DNA extracted from abyssal sediments preserves patterns of plankton macroecology

    Directory of Open Access Journals (Sweden)

    R. Morard

    2017-06-01

    Full Text Available Deep-sea sediments constitute a unique archive of ocean change, fueled by a permanent rain of mineral and organic remains from the surface ocean. Until now, paleo-ecological analyses of this archive have been mostly based on information from taxa leaving fossils. In theory, environmental DNA (eDNA in the sediment has the potential to provide information on non-fossilized taxa, allowing more comprehensive interpretations of the fossil record. Yet, the process controlling the transport and deposition of eDNA onto the sediment and the extent to which it preserves the features of past oceanic biota remains unknown. Planktonic foraminifera are the ideal taxa to allow an assessment of the eDNA signal modification during deposition because their fossils are well preserved in the sediment and their morphological taxonomy is documented by DNA barcodes. Specifically, we re-analyze foraminiferal-specific metabarcodes from 31 deep-sea sediment samples, which were shown to contain a small fraction of sequences from planktonic foraminifera. We confirm that the largest portion of the metabarcode originates from benthic bottom-dwelling foraminifera, representing the in situ community, but a small portion (< 10 % of the metabarcodes can be unambiguously assigned to planktonic taxa. These organisms live exclusively in the surface ocean and the recovered barcodes thus represent an allochthonous component deposited with the rain of organic remains from the surface ocean. We take advantage of the planktonic foraminifera portion of the metabarcodes to establish to what extent the structure of the surface ocean biota is preserved in sedimentary eDNA. We show that planktonic foraminifera DNA is preserved in a range of marine sediment types, the composition of the recovered eDNA metabarcode is replicable and that both the similarity structure and the diversity pattern are preserved. Our results suggest that sedimentary eDNA could preserve the ecological structure of

  16. Low Latitude Pelagic Foraminifera Found in the Hudson River: Are They Hurricane Deposits?

    Science.gov (United States)

    Monahan, K. M.; Abbott, D. H.; Hoenisch, B.; Breger, D.

    2011-12-01

    River sediment cores provide a record of past environmental changes through stacked layers of sediments. In core CD02-29A, recovered from the southern Hudson River, a significant number of tropical planktic foraminifer tests were found. Foraminifera were concentrated in sediment layers of low impedance, suggesting high carbonate content. Because modern planktic foraminifera are exclusively marine, their presence in Hudson sediments in the core was remarkable. We can think of only two mechanisms that could explain this observation: either living specimens are carried upriver with the daily tides, or storm surges carry large amounts of seawater and re-suspended marine sediment upriver. To test for the presence of living specimens in Hudson River water, plankton tow samples were collected during high tide at the Hudson Battery south of the sample site, and at Piermont Pier north of the sample site and no living foraminifera were found. In addition, oxygen isotope (δ18O) analyses reveal a marine composition but the large difference in δ18O between the two surface dwelling species Globigerinoides ruber (pink) and Globigerinoides sacculifer, picked from the same sediment layer, suggests re-suspension and mixing of marine sediment deposits. Because only planktic, tropical to subtropical foraminiferal assemblages were found, the Hudson River deposits differ from previously recorded storm deposits found on Long Island and in New Jersey. In particular, the foraminiferal assemblages contain up to 40% G. ruber (pink), suggesting a highly tropical signal from a location where abundances of G. ruber are very low. This data, in addition to the pulsed occurrence of tests in the sediment suggests that the introduction of planktic foraminifera into the Hudson River must be driven by rare events. We suggest that storm surges from rare high-intensity hurricanes most likely explain the presence of these tests in Hudson River sediments, possibly assisted by the Gulf Stream entraining

  17. Teddy Bear Stories

    DEFF Research Database (Denmark)

    van Leeuwen, Theo; Caldas-Coulthardt, Carmen

    2014-01-01

    This paper presents a semiotic analysis of a key cultural artefact, the teddy bear. After introducing the iconography of the teddy bear, it analyses different kinds of stories to show how teddy bears are endowed with meaning in everyday life: stories from children's books, reminiscenses by adults...... bears have traditionally centred on interpersonal relations within the nuclear family, but have recently been institutionalized and commercialized....

  18. Spatial and temporal distribution patterns of benthic foraminifera in the Northeast Water Polynya, Greenland

    Science.gov (United States)

    Ahrens, Michael J.; Graf, Gerhard; Altenbach, Alexander V.

    1997-01-01

    Abundance, biofacies and ATP content of benthic foraminifera (>63 μm) were studied in the Northeast Water (NEW) Polynya (77-81°N, 5-17°W) over the ice-free summer, 1993, to investigate how a polynya system might influence the underlying benthic community. In the living assemblage, distinguished by Rose Bengal staining, over 60 taxa could be identified. The biofacies identified was similar to that of other Arctic shelf habitats. Foraminifera were counted in 3 size fractions (63-125 μm, 125-250 μm and >250 μm), with 65% of the foraminifera occurring in the smallest size fraction (63-125 μm). Total abundances (>63 μm) in the uppermost 1 cm averaged approximately 200 ind/10 cm 3 and declined down-core, as did the number of species. Abundances and species composition correlated positively with sediment chlorophyll and ATP content, with maxima occurring in the shallower northern regions of the polynya, suggesting a general dependence on food. Foraminera biomass was estimated to be 0.1-0.3 g C org/m 2. Abundances, biomass and ATP content were comparable to ice-free, deep-sea regions in the Norwegian Sea. Temporal changes observed over a 2 month period at one location were difficult to distinguish from spatial and analytical variability. Contrary to expectations, growth was unpronounced at the community and at a species level, implying either a delayed response of the benthic foraminiferal community to food inputs from the overlying water column or the presence of biological limitations other than food, such as predation.

  19. Living Behaviors and Molecular Characterization of Benthic Foraminifera in the Arabian Gulf

    Science.gov (United States)

    Arslan, Muhammad; Kaminski, Michael; Khalil, Amjad; Holzmann, Maria

    2016-04-01

    The benthic foraminifera are among the major carbonate producers in modern Arabian Gulf waters and are found living in all marine habitats. They have been recognized as proxies to assess paleoenvironmental changes, however, their biological behaviors in modern environments needs to be further studied. The current study attempts to explain the biology of benthic foraminifera in terms of their living behaviors and molecular characterization, from different regions of the western side of the Arabian Gulf. Accordingly, two major groups of benthic foraminifera, namely rotaliids and miliolids, are examined under laboratory conditions. Results illustrate that the rotaliids are more resistant to environmental changes than miliolids, as their granular reticulopodial network is stronger than among the miliolids, with high cytoplasmic streaming. The pseudopodia extend out from both primary and secondary apertures, and aid the organism in locomotion by attaching to the wall of hard substrate. As a result they drag their whole bodies toward the direction of motion. In rotaliids, the movement rate is high and is attributed to the extension of pseudopodia through all apertures, compared with miliolids in which pseudopodia extend out from the primary aperture only. The innate behavior of both groups was observed as a function of external stimulus, i.e., light, nutrients, and availability of substrate. The observation on average life span reflected that the rotaliids was able to survive longer than miliolids. Molecular analysis reveals the presence of four groups, i.e., Ammonia, Murrayinella, Glabratellina, and Elphidium which support the morphological taxonomy at the genus level. However, BLAST analysis contradicts the species level taxonomy, which challenges the classification based upon hard-shell morphology. Nevertheless, monophyletic clustering is observed among all major groups. The study concludes that the morphological taxonomy needs to be augmented by molecular analysis

  20. Diversity, distribution, and morphological deformities among living Foraminifera in hypersaline Salwa Bay, Saudi Arabia

    Science.gov (United States)

    Olalekan Amao, Abduljamiu; Kaminski, Michael

    2016-04-01

    The Arabian Gulf is considered a naturally stressed environment due to extremes of salinity and summer temperatures. Anthropogenic influences such as rapid urbanisation projects, maritime transport, and large numbers of desalination plants and oil-related activities compounds the problem. Foraminifera are known to be resilient under such stressful conditions. The purpose of our study is to document the foraminiferal diversity and abundance in the hypersaline Salwa Bay area, near the Saudi Arabian-Qatar Border. We expect the foraminiferal fauna in Salwa Bay to be adapted to extremes in salinity, and we wish to document any species that might be endemic or uniquely adapted to the area. Shannon-Wiener index, relative abundance, species richness, and the percentage of morphological deformities were determined for samples collected from the bay. Salwa Bay is the most saline extension of the Arabian Gulf with high salinity, water temperature and evaporation rate, which is attributed to slow flushing rates, coral reef barriers and higher residency time of the water. Environmental parameters measured at the time of collection were depth (10-110 cm), salinity (52.6-53.0) total dissolved solids (48.8-49.4 g/l), and temperature (27-27.6°C). The foraminiferal assemblages in Salwa Bay are dominated by porcelaneous foraminifera, which include Peneroplis pertusus, Peneroplis planatus, Coscinospira hemprichii and Coscinospira acicularis. The most common species across the sampled transect is Peneroplis pertusus. Hyaline species were also found, but agglutinated foraminifera are absent. Diversity in Salwa Bay is lower compared with localities that have "normal" salinity, and many of the foraminifera display conspicuous morphological deformities. Approximately 55% of the assemblage exhibits mild to severe deformities such as fusion of two adults or double tests, protuberance on the spiral side, abnormal arrangement of the chambers, abnormal shape of the proloculus and modification

  1. Does temperature affect dimorphic reproduction in benthic foraminifera? A culture experiment on Rosalina leei

    Digital Repository Service at National Institute of Oceanography (India)

    Nigam, R.; Caron, D.A.

    ,15 . ? For correspondence. (e - mail: nigam@csnio.ren.nic.in ) First, a preliminary survey was made for collection of benthic foraminifera from sea grasses and surface sed i- ment samples from three locations near Woods Hole, Massachusetts, USA, viz. (i) Vineyar d..., 15 , 26 ? 34. 3. Rottger, R., Fladung, M., Schmaljo hann, R., Spi n dler, M. and Zacharias, H., J. Foram. Res ., 1986, 16 , 141 ? 149. 4. Harney, J. N., Hallock, P. and Jalge, H. K., J. F o ram. Res ., 1998, 28 , 141 ? 147. 5. Lee, J...

  2. Polar bears, Ursus maritimus

    Science.gov (United States)

    Rode, Karyn D.; Stirling, Ian

    2017-01-01

    Polar bears are the largest of the eight species of bears found worldwide and are covered in a pigment-free fur giving them the appearance of being white. They are the most carnivorous of bear species consuming a high-fat diet, primarily of ice-associated seals and other marine mammals. They range throughout the circumpolar Arctic to the southernmost extent of seasonal pack ice.

  3. EcoBears

    DEFF Research Database (Denmark)

    Nielsen, Nick; Pedersen, Sandra Bleuenn; Sørensen, Jens Ager

    2015-01-01

    In this paper, we introduce the EcoBears concept that aims to augment household appliances with functional and aesthetic features to promote their "use'' and "longevity of use'' to prevent their disposal. The EcoBears also aim to support the communication of environmental issues in the home setting....... We present our initial design and implementation of the EcoBears that consist of two bear modules (a mother and her cub). We also present our preliminary concept validations and lessons learned to be considered for future directions....

  4. Bearing restoration by grinding

    Science.gov (United States)

    Hanau, H.; Parker, R. J.; Zaretsky, E. V.; Chen, S. M.; Bull, H. L.

    1976-01-01

    A joint program was undertaken by the NASA Lewis Research Center and the Army Aviation Systems Command to restore by grinding those rolling-element bearings which are currently being discarded at aircraft engine and transmission overhaul. Three bearing types were selected from the UH-1 helicopter engine (T-53) and transmission for the pilot program. No bearing failures occurred related to the restoration by grinding process. The risk and cost of a bearing restoration by grinding programs was analyzed. A microeconomic impact analysis was performed.

  5. Polar bears at risk

    Energy Technology Data Exchange (ETDEWEB)

    Norris, S.; Rosentrater, L.; Eid, P.M. [WWF International Arctic Programme, Oslo (Norway)

    2002-05-01

    Polar bears, the world's largest terrestrial carnivore, spend much of their lives on the arctic sea ice. This is where they hunt and move between feeding, denning, and resting areas. The world population, estimated at 22,000 bears, is made up of 20 relatively distinct populations varying in size from a few hundred to a few thousand animals. About 60 per cent of all polar bears are found in Canada. In general, the status of this species is stable, although there are pronounced differences between populations. Reductions in the extent and thickness of sea ice has lead the IUCN Polar Bear Specialist Group to describe climate change as one of the major threats facing polar bears today. Though the long-term effects of climate change will vary in different areas of the Arctic, impacts on the condition and reproductive success of polar bears and their prey are likely to be negative. Longer ice-free periods resulting from earlier break-up of sea ice in the spring and later formation in the fall is already impacting polar bears in the southern portions of their range. In Canada's Hudson Bay, for example, bears hunt on the ice through the winter and into early summer, after which the ice melts completely, forcing bears ashore to fast on stored fat until freeze-up in the fall. The time bears have on the ice to hunt and build up their body condition is cut short when the ice melts early. Studies from Hudson Bay show that for every week earlier that ice break-up occurs, bears will come ashore 10 kg lighter and in poorer condition. It is likely that populations of polar bears dividing their time between land and sea will be severely reduced and local extinctions may occur as greenhouse gas emissions continue to rise and sea ice melts. Expected changes in regional weather patterns will also impact polar bears. Rain in the late winter can cause maternity dens to collapse before females and cubs have departed, thus exposing occupants to the elements and to predators. Such

  6. Diachronous ranges of benthonic Foraminifera in the Eocene of Alabama and South Carolina

    International Nuclear Information System (INIS)

    Willard, G.D.; Fallaw, W.C.; Snipes, D.S.

    1994-01-01

    Seventeen species of benthonic Foraminifera reported by Bandy (1949) from the Eocene of Little Stave Creek in Clarke County, Alabama were identified from the middle eocene Santee Limestone and the upper Eocene Dry Branch Formation in Aiken and Barnwell counties, South Carolina. Of the 17 species, seven occurred in South Carolina stratigraphically above or below the ranges listed by Bandy. Bandy made a detailed study of Foraminifera from the Claibornian and Jacksonian Tallahatta, Lisbon, Gosport, Moodys Branch, and Yazoo formations exposed on Little Stave Creek and plotted the stratigraphic ranges within the section of numerous species. The authors' samples came from well cores at the Savannah River Site in South Carolina. Of 13 species from the middle Eocene Santee and also reported by Bandy, four are stratigraphically below the lowest occurrence listed by Bandy, and one is stratigraphically above the highest occurrence. Of four species from the upper Eocene Dry Branch Formation and also listed by Bandy, two are stratigraphically above his highest occurrence. Dockery and Nystrom (1992) and Campbell (1993) have described diachroneity among mollusks in the Eocene of South Carolina. Caution should be used in relying on a small number of species in correlating Eocene deposits in the Atlantic and Gulf coastal plains

  7. Response of deep-sea benthic foraminifera to Miocene paleoclimatic events, DSDP site 289

    International Nuclear Information System (INIS)

    Woodruff, F.; Douglas, R.G.

    1981-01-01

    Changes in the Miocene deep-sea benthic foraminifera at DSDP Site 289 closely correlate to the climatically induced variations in deep and bottom waters in the Pacific Ocean. In early Miocene time, oxygen and carbon isotopes indicate that bottom waters were relatively warm and poorly oxygenated. Benthic foraminiferal assemblages are characterized by various species inherited from the Oligocene. Expansion of the Antarctic icecap in the early middle Miocene, 14-16 m.y. ago, increased oxygen isotope values, produced cold, more oxygenated bottom waters and lead to a turnover in the benthic foraminifera. An Oligocene-early Miocene assemblage was replaced by a cibicidoid-dominated assemblage. Some species became extinct and benthic faunas became more bathymetrically restricted with the increased stratification of deep waters in the ocean. In mid-Miocene time, Epistominella exigua and E. umbonifera, indicative of young, oxygenated bottom waters, are relatively common at DSDP Site 289. Further glacial expansion 5-9 m.y. ago lowered sealevel, increased oceanic upwelling and associated biological productivity and intensified the oxygen minima. Abundant hispid and costate uvigerines become a dominant faunal element at shallow depths above 2500 m as E. umbonifera becomes common to abundant below 2500 m. By late Miocene time, benthic faunas similar in species composition and proportion to modern faunas on the Ontong-Java plateau, had become established. (Auth.)

  8. Seaweed fails to prevent ocean acidification impact on foraminifera along a shallow-water CO2 gradient.

    Science.gov (United States)

    Pettit, Laura R; Smart, Christopher W; Hart, Malcolm B; Milazzo, Marco; Hall-Spencer, Jason M

    2015-05-01

    Ocean acidification causes biodiversity loss, alters ecosystems, and may impact food security, as shells of small organisms dissolve easily in corrosive waters. There is a suggestion that photosynthetic organisms could mitigate ocean acidification on a local scale, through seagrass protection or seaweed cultivation, as net ecosystem organic production raises the saturation state of calcium carbonate making seawater less corrosive. Here, we used a natural gradient in calcium carbonate saturation, caused by shallow-water CO2 seeps in the Mediterranean Sea, to assess whether seaweed that is resistant to acidification (Padina pavonica) could prevent adverse effects of acidification on epiphytic foraminifera. We found a reduction in the number of species of foraminifera as calcium carbonate saturation state fell and that the assemblage shifted from one dominated by calcareous species at reference sites (pH ∼8.19) to one dominated by agglutinated foraminifera at elevated levels of CO2 (pH ∼7.71). It is expected that ocean acidification will result in changes in foraminiferal assemblage composition and agglutinated forms may become more prevalent. Although Padina did not prevent adverse effects of ocean acidification, high biomass stands of seagrass or seaweed farms might be more successful in protecting epiphytic foraminifera.

  9. Foraminifera, Thecamoebians and Palynomorphs as Hydrodynamic Indicators in Araguari Estuary, Amazonian Coast, Amapá State – Brazil

    Directory of Open Access Journals (Sweden)

    Odete Fátima Machado

    2010-01-01

    Full Text Available The Araguari estuarine dynamics is singular among traditional models of estuaries under tidal regime due to influence of macrotidal and tidal bore. In order to establish estuarine zones in Araguari according foraminifera, thecamoebians, paliynomorphs and physical-chemistry parameters, sixteen sample stations were established along the estuary. Turbidity and temperature were the environmental parameters which allowed determination of the estuarine gradient. Eighteen species of foraminifera, ten of thecamoebians and fourteen of particulate organic matter types were identified. Cluster analysis in R-mode showed three microorganism assemblages and four palynomorph ones. The CCA analyze shows turbidity and total organic matter with the most influence over foraminiferal and thecamoebians distribution at Araguari. Clustering analysis in Q-mode using all data formed four groups suggesting three estuarine zones in Araguari: Zone I composed of thecamoebian species and continental palynomorphs; Zone II - composed by mangrove foraminifera, thecamoebians and all palynomorph assemblages; and Zone III – composed by mangrove and estuarine foraminifera and all palynomorph assemblages.

  10. Marine connections of Amazonia: Evidence from foraminifera and dinoflagellate cysts (early to middle Miocene, Colombia/Peru)

    NARCIS (Netherlands)

    Boonstra, M.; Ramos, M.I.F.; Lammertsma, E.I.; Antoine, P.-O; Hoorn, C.

    2015-01-01

    Species composition in the present-day Amazonian heartland has an imprint of past marine influence. The exact nature, timing and extent of this marine influence, however, are largely unresolved. Here we use calcareous tests of foraminifera and marine palynomorphs from Miocene sediments in

  11. Four new species of deep water agglutinated foraminifera from the Oligocene-Miocene of the Congo Fan (offshore Angola)

    OpenAIRE

    Kender, S.; Kaminski, M. A.; Jones, R. W.

    2006-01-01

    Four new species of deep-water agglutinated benthic foraminifera are described from the Oligocene and Miocene of the Congo Fan, offshore Angola. Scherochorella congoensis n.sp., Paratrochamminoides goroyskiformis n.sp., Haplophragmoides nauticus n.sp. and Portatrochammina profunda n.sp. all occur in deep-sea turbiditic shales and sands from the distal section of the Congo Fan.

  12. Recent benthic foraminifera and sedimentary facies from mangrove swamps and channels of Abu Dhabi (United Arab Emirates)

    Science.gov (United States)

    Fiorini, Flavia; Odeh, Weaam A. S. Al; Lokier, Stephen W.; Paul, Andreas

    2016-04-01

    Zonation of Recent mangrove environments can be defined using benthic foraminifera, however, little is known about foraminifera from mangrove environments of the Arabian Gulf. The objective of this study is to produce a detailed micropaleontological and sedimentological analysis to identify foraminiferal associations in several coastline environments (mangrove swamps and channels) located on the eastern side of Abu Dhabi Island (UAE). Detailed sediment sampling collection in mangal environments of Eastern Abu Dhabi was carried out to assess the distribution of living and dead benthic foraminifera in different sedimentary facies in the mangal and in the surrounding area comprising natural environments of the upper and lower intertidal area (mud flats and channels) and areas modified by anthropogenic activities (dredged channels). The fine-grain sediments collected near mangrove (Avicenna marina) roots presented a high abundance of living and dead foraminifera tests. The assemblages in these samples show very low diversity and are almost entirely constituted of small-sized opportunistic species belonging to the genera Ammonia and Elphidium. In particular: • Samples collected on the mud flat and in ponds at the margin of the channel show a foraminiferal assemblage characterised by abundant foraminifera belonging to the genera Ammonia, Elphidium, Triloculina, Quinqueloculina, Peneroplis and Spirolina. • Samples collected in the lower (wet) intertidal area close to Avicenna marina roots, presented a low-diversity assemblage mostly comprising opportunistic foraminifera of the genera Ammonia and Elphidium along with rare miliolidae. • Samples from the upper intertidal area (dry) close to Avicenna marina roots, produced an assemblage exclusively composed of small-sized opportunistic Ammonia and Elphidium, together with abundant specimens belonging to the genera Trochammina. Throchammina specimens have not been previously recorded from Recent sedimentary samples of

  13. Benthic foraminifera

    Digital Repository Service at National Institute of Oceanography (India)

    Saraswat, R.; Nigam, R.

    (Nolet and Corliss, 1990). Differences in the abundance of oxygen-sensitive and dissolution-prone benthic foraminiferal species between the Last Glacial Maximum (LGM) and the Holocene in the abyssal waters of the southwestern Gulf of Mexico were used... (2009) Deep-sea benthic diversity linked to seasonality of pelagic productivity. Deep Sea Research Part I: Oceanographic Research Papers 56: 835-841. Culver S (1988) New foraminiferal depth zonation of the northwestern Gulf of Mexico. Palaios 3: 69...

  14. Ultra-precision bearings

    CERN Document Server

    Wardle, F

    2015-01-01

    Ultra-precision bearings can achieve extreme accuracy of rotation, making them ideal for use in numerous applications across a variety of fields, including hard disk drives, roundness measuring machines and optical scanners. Ultraprecision Bearings provides a detailed review of the different types of bearing and their properties, as well as an analysis of the factors that influence motion error, stiffness and damping. Following an introduction to basic principles of motion error, each chapter of the book is then devoted to the basic principles and properties of a specific type of bearin

  15. Early Miocene benthic foraminifera and biostratigraphy of the Qom Formation, Deh Namak, Central Iran

    Science.gov (United States)

    Daneshian, Jahanbakhsh; Dana, Leila Ramezani

    2007-03-01

    A total of 165 samples were collected from the Qom Formation investigated in a stratigraphic section north of Deh Namak, in Central Iran. From these, 35 genera and 47 species of benthic foraminifera were identified. The age of the studied section is Early Miocene (Aquitanian to Early Burdigalian) based on the occurrence of Borelis melo curdica, Meandropsina anahensis, Meandropsina iranica, Elphidium sp. 14, Peneroplis farsensis, and Triloculina tricarinata. The thickness of the Qom Formation is 401 m of which 161.2 m is early Burdigalian in age. Foraminiferal assemblages in the Deh Namak section are referable to the Borelis melo group- Meandropsina iranica Assemblage Zone and Miogypsinoides- Archaias-Valvulinid Assemblage Zone of [Adams, T.D., Bourgeois, F., 1967. Asmari biostratigraphy. Iranian Oil Operating Companies, Geological and Exploration Division, Report1074 (unpublished) 1-37.] described originally from the Asmari Formation.

  16. Biological fractionation of oxygen and carbon isotopes by recent benthic foraminifera

    International Nuclear Information System (INIS)

    Woodruff, F.; Douglas, R.G.

    1980-01-01

    Recent deep-sea benthic foraminifera from five East Pacific Rise box core tops have been analyzed for oxygen and carbon isotopic composition. The five equatorial stations, with water depths of between 3200 and 4600 m, yielded fourteen specific and generic taxonomic groups. Of the taxa analyzed, Uvigerina spp. most closely approaches oxygen isotopic equilibrium with ambient sea water. Pyrgo spp. was next closest to isotopic equilibrium, being on the average 0.59 per thousand depleted in 18 O relative to Uvigerina spp. Oridorsalis umbonatus also has relatively high delta 18 O values. Most other taxa were depleted in 18 O by large amounts. In no taxa was the carbon in the CaCO 3 secreted in carbon isotopic equilibrium with the dissolved HCO 3 - of ambient sea water. (Auth.)

  17. Species dominance and equitability: patterns in Cenozoic foraminifera of eastern North America

    Science.gov (United States)

    Gibson, T.G.; Hill, E.E.

    1992-01-01

    Species dominance in benthonic foraminifera, represented by percent of the assemblage composed of the single most abundant species, shows little change in observed range of values from shallow into deep-marine waters in 1005 samples from the Gulf of Mexico, Atlantic, and Arctic margins of North America. This finding contrasts with the model that species dominance is highest in shallow-marine environments and decreases offshore into deeper marine waters. Equitability, the relation of all species abundances within an assemblage, also shows little change between the values found in shallow-marine assemblages and those found in assemblages from deeper water environments. Equitability and dominance values found in 421 assemblages from Palaeocene, Eocene, Miocene, and Pleistocene strata of the Atlantic and E Gulf of Mexico coastal plains are similar to the modern values. -from Authors

  18. Burdigalian turbid water patch reef environment revealed by larger benthic foraminifera

    Science.gov (United States)

    Novak, V.; Renema, W.; Throughflow-project

    2012-04-01

    Ancient isolated patch reefs outcropping from siliciclastic sediments are a trademark for the Miocene carbonate deposits occurring in East Kalimantan, Indonesia. They develop in transitional shelf sediments deposited between deltaic and deep marine deposits (Allen and Chambers, 1998). The Batu Putih Limestone (Wilson, 2005) and similar outcrops in adjacent areas have been characterized as shallow water carbonates influenced by high siliciclastic input, showing low relief patch reefs in turbid waters. Larger benthic foraminifera (LBF) are excellent markers for biochronology and paleoenvironmental reconstruction. This study aims to reveal age and paleoenvironment of a shallow water carbonate patch reef developed in mixed depositional system by using LBF and microfacies analysis. The studied section is located near Bontang, East Kalimantan, and is approximately 80 m long and 12 m high. It is placed within Miocene sediments in the central part of the Kutai Basin. Patch reef and capping sediments were logged through eight transects along section and divided into nine different lithological units from which samples were collected. Thin sections and isolated specimens of larger benthic foraminifera were analyzed and recognized to species level (where possible) providing age and environmental information. Microfacies analysis of thin sections included carbonate classification (textural scheme of Dunham, 1962) and assemblage composition of LBF, algae and corals relative abundance. Three environmentally indicative groups of LBF were separated based on test morphology, habitat or living relatives (Hallock and Glenn, 1986). Analysed foraminifera assemblage suggests Burdigalian age (Tf1). With use of microfacies analysis nine successive lithological units were grouped into five facies types. Paleoenvironmental reconstruction of LBF fossil assemblage indicate two cycles of possible deepening recorded in the section. Based on high muddy matrix ratio in analyzed thin-sections we

  19. Rapid deterioration of sediment surface habitats in Bellingham Bay, Washington State, as indicated by benthic foraminifera.

    Science.gov (United States)

    Nesbitt, Elizabeth A; Martin, Ruth A; Martin, David E; Apple, Jude

    2015-08-15

    Foraminiferal assemblages in sediment grab samples were utilized to evaluate the impacts of anthropogenic activities on benthic habitats in Bellingham Bay, Washington State, U.S.A. Seventy-three samples taken in 1987, 1997, 2006 and 2010 yielded 35 species of foraminifera from 28 genera. Assemblage composition and diversity data indicate a marked deterioration between 1987 and 2010, contrary to the published Chemical Index, but analogous to the situation with macrobiota. Correlation of diversity with chemical pollutants and metals did not identify any significant correlations, however, an unrelated but highly relevant study of bottom water dissolved oxygen concentrations and pH in Bellingham Bay suggests eutrophication with accompanying hypoxia and acidification may be part of the cause. Thus, the metrics of contamination alone do not adequately characterize habitat viability, and benthic foraminiferal assemblages provide insight into the health of coastal ecosystems. Published by Elsevier Ltd.

  20. Equivalent dose determination in foraminifera: analytical description of the CO2--signal dose-response curve

    International Nuclear Information System (INIS)

    Hoffmann, D.; Woda, C.; Mangini, A.

    2003-01-01

    The dose-response of the CO 2 - signal (g=2.0006) in foraminifera with ages between 19 and 300 ka is investigated. The sum of two exponential saturation functions is an adequate function to describe the dose-response curve up to an additional dose of 8000 Gy. It yields excellent dating results but requires an artificial doses of at least 5000 Gy. For small additional doses of about 500 Gy the single exponential saturation function can be used to calculate a reliable equivalent dose D E , although it does not describ the dose-response for higher doses. The CO 2 - -signal dose-response indicates that the signal has two components of which one is less stable than the other

  1. Can abundance of protists be inferred from sequence data: a case study of foraminifera.

    Directory of Open Access Journals (Sweden)

    Alexandra A-T Weber

    Full Text Available Protists are key players in microbial communities, yet our understanding of their role in ecosystem functioning is seriously impeded by difficulties in identification of protistan species and their quantification. Current microscopy-based methods used for determining the abundance of protists are tedious and often show a low taxonomic resolution. Recent development of next-generation sequencing technologies offered a very powerful tool for studying the richness of protistan communities. Still, the relationship between abundance of species and number of sequences remains subjected to various technical and biological biases. Here, we test the impact of some of these biological biases on sequence abundance of SSU rRNA gene in foraminifera. First, we quantified the rDNA copy number and rRNA expression level of three species of foraminifera by qPCR. Then, we prepared five mock communities with these species, two in equal proportions and three with one species ten times more abundant. The libraries of rDNA and cDNA of the mock communities were constructed, Sanger sequenced and the sequence abundance was calculated. The initial species proportions were compared to the raw sequence proportions as well as to the sequence abundance normalized by rDNA copy number and rRNA expression level per species. Our results showed that without normalization, all sequence data differed significantly from the initial proportions. After normalization, the congruence between the number of sequences and number of specimens was much better. We conclude that without normalization, species abundance determination based on sequence data was not possible because of the effect of biological biases. Nevertheless, by taking into account the variation of rDNA copy number and rRNA expression level we were able to infer species abundance, suggesting that our approach can be successful in controlled conditions.

  2. Lunar periodicity in the shell flux of planktonic foraminifera in the Gulf of Mexico

    Science.gov (United States)

    Jonkers, Lukas; Reynolds, Caitlin E.; Richey, Julie N.; Hall, Ian R.

    2015-01-01

    Synchronised reproduction offers clear benefits to planktonic foraminifera – an important group of marine calcifiers – as it increases the chances of successful gamete fusion. Such synchrony requires tuning to an internal or external clock. Evidence exists for lunar reproductive cycles in some species, but its recognition in shell flux time series has proven difficult, raising questions about reproductive strategies. Using spectral analysis of a 4-year time series (mostly at weekly resolution) from the northern Gulf of Mexico, we show that the shell flux ofGloborotalia menardii, Globigerinella siphonifera, Orbulina universa, Globigerinoides sacculifer, Globigerinoides ruber (both pink and white varieties), Pulleniatina obliquiloculata, Neogloboquadrina dutertrei, Globigerinella calida and Globigerinita glutinata is characterised by lunar periodicity. However, the lunar rhythm is not present in all size fractions of each species and tends to be more dominant in the flux of larger shells, consistent with reproduction being more prevalent in larger specimens. Lunar periodicity is superimposed on longer term/seasonal changes in the shell fluxes, but accounts for a significant part of the variance in the fluxes. The amplitude of the lunar cycle increases roughly proportional with the magnitude of the flux, demonstrating that most of the population is indeed affected by lunar-phased synchronisation. In most species peak fluxes occur predominantly around, or just after, full moon. Only G. siphonifera and G. calida show a contrasting pattern with peaks concentrated around new moon. Although the exact cause of the synchronisation remains elusive, our data considerably increase the number of species for which lunar synchronised reproduction is reported and suggest that such reproductive behaviour is common in many species of planktonic foraminifera.

  3. Deglacial Western Equatorial Pacific pCO2 Reconstruction Using Boron Isotopes of Planktonic Foraminiferas

    Science.gov (United States)

    Kubota, K.; Yokoyama, Y.; Ishikawa, T.; Sagawa, T.; Ikehara, M.; Yamazaki, T.

    2017-12-01

    During the last deglaciation (ca. 19 - 11 ka), partial pressure of CO2 (pCO2) of the atmosphere increased by 80 μatm. Many paleoceanographers point out that the ocean had played an important role in atmospheric CO2 rise, since the ocean have 60 times larger capacity to store carbon compared to the atmosphere. However, evidence on where carbon was transferred from the ocean to the atmosphere is still lacking, hampering our understanding of global carbon cycles in glacial-interglacial timescales. Boron isotope of skeletons of marine calcifying organisms such as corals and foraminiferas can pin down where CO2 source/sink existed, because boron isotopes of marine calcium carbonates is dependent on seawater pH, from which pCO2 of the past seawater can be reconstructed. In previous studies using the boron isotope teqnique, Martinez-Boti et al. (2015, Nature) and Kubota et al. (2014, Scientific Reports) revealed that central and eastern parts of the equatorial Pacific acted as a CO2 source (i.e., CO2 emission) during the last deglaciation, suggesting the equatorial Pacific's contribution to atmospheric CO2 rise. However, some conflicting results have been confirmed in a marine sediment record from the western part of the equatorial Pacific (Palmer & Pearson, 2003, Science), making the conclusion elusive. In this presentation, we will show new results of Mg/Ca, oxygen isotope, and boron isotope measurements during the last 35 ka on two species of surface dwelling foraminiferas (Globigerinoides ruber and G. sacculifer) which was hand-picked separatedly from a well-dated marine sediment core recovered from the West Caroline Basin (KR05-15 PC01) (Yamazaki et al., 2008, GRL). From the new records, we will discuss how the equatorial Pacific behaved during the last deglaciation and how it related to the global carbon cycles.

  4. Arrival and expansion of the invasive foraminifera Trochammina hadai Uchio in Padilla Bay, Washington

    Science.gov (United States)

    McGann, Mary; Grossman, Eric E.; Takesue, Renee K.; Penttila, Dan; Walsh, John P.; Corbett, Reide

    2012-01-01

    Trochammina hadai Uchio, a benthic foraminifera native to Japanese estuaries, was first identified as an invasive in 1995 in San Francisco Bay and later in 16 other west coast estuaries. To investigate the timing of the arrival and expansion of this invasive species in Padilla Bay, Washington, we analyzed the distribution of foraminifera in two surface samples collected in 1971, in nine surface samples collected by Scott in 1972–1973, as well as in two cores (Padilla Flats 3 and Padilla V1/V2) obtained in 2004. Trochanimina hadai, originally identified as the native Trochammina pacifica Cushman in several early foraminiferal studies, dominates the assemblage of most of the surface samples. In the Padilla V1/V2 and Padilla Flats 3 cores, the species' abundance follows a pattern of absence, first appearance, rapid expansion commonly seen shortly after the arrival of a successful biological invasion, setback, and second expansion. Using Q-mode cluster analysis, pre-expansion and expansion assemblages were identified. Pb-210 dating of these cores proved unsuccessful. However, based on T. hadai's first appearance occurring stratigraphically well above sedimentological changes in the cores that reflect deposition of sediments in the bay due to previous diversions of the Skagit River, and its dominance in the early 1970s surface samples, we conclude that the species arrived in Padilla Bay somewhere between the late 1800s and 1971. Trochammina hadai may have been introduced into the bay in the 1930s when oyster culturing began there or, at a minimum, ten years prior to its appearance in San Francisco Bay.

  5. A decline in benthic foraminifera following the deepwater horizon event in the northeastern Gulf of Mexico.

    Science.gov (United States)

    Schwing, Patrick T; Romero, Isabel C; Brooks, Gregg R; Hastings, David W; Larson, Rebekka A; Hollander, David J

    2015-01-01

    Sediment cores were collected from three sites (1000-1200 m water depth) in the northeastern Gulf of Mexico from December 2010 to June 2011 to assess changes in benthic foraminiferal density related to the Deepwater Horizon (DWH) event (April-July 2010, 1500 m water depth). Short-lived radioisotope geochronologies (²¹⁰Pb, ²³⁴Th), organic geochemical assessments, and redox metal concentrations were determined to relate changes in sediment accumulation rate, contamination, and redox conditions with benthic foraminiferal density. Cores collected in December 2010 indicated a decline in density (80-93%). This decline was characterized by a decrease in benthic foraminiferal density and benthic foraminiferal accumulation rate (BFAR) in the surface 10 mm relative to the down-core mean in all benthic foraminifera, including the dominant genera (Bulimina spp., Uvigerina spp., and Cibicidoides spp.). Cores collected in February 2011 documented a site-specific response. There was evidence of a recovery in the benthic foraminiferal density and BFAR at the site closest to the wellhead (45 NM, NE). However, the site farther afield (60 NM, NE) recorded a continued decline in benthic foraminiferal density and BFAR down to near-zero values. This decline in benthic foraminiferal density occurred simultaneously with abrupt increases in sedimentary accumulation rates, polycyclic aromatic hydrocarbon (PAH) concentrations, and changes in redox conditions. Persistent reducing conditions (as many as 10 months after the event) in the surface of these core records were a possible cause of the decline. Another possible cause was the increase (2-3 times background) in PAH's, which are known to cause benthic foraminifera mortality and inhibit reproduction. Records of benthic foraminiferal density coupled with short-lived radionuclide geochronology and organic geochemistry were effective in quantifying the benthic response and will continue to be a valuable tool in determining the long

  6. Benthic foraminifera baseline assemblages from a coastal nearshore reef complex on the central Great Barrier Reef

    Science.gov (United States)

    Johnson, Jamie; Perry, Chris; Smithers, Scott; Morgan, Kyle

    2016-04-01

    Declining water quality due to river catchment modification since European settlement (c. 1850 A.D.) represents a major threat to the health of coral reefs on Australia's Great Barrier Reef (GBR), particularly for those located in the coastal waters of the GBR's inner-shelf. These nearshore reefs are widely perceived to be most susceptible to declining water quality owing to their close proximity to river point sources. Despite this, nearshore reefs have been relatively poorly studied with the impacts and magnitudes of environmental degradation still remaining unclear. This is largely due to ongoing debates concerning the significance of increased sediment yields against naturally high background sedimentary regimes. Benthic foraminifera are increasingly used as tools for monitoring environmental and ecological change on coral reefs. On the GBR, the majority of studies have focussed on the spatial distributions of contemporary benthic foraminiferal assemblages. While baseline assemblages from other environments (e.g. inshore reefs and mangroves) have been described, very few records exist for nearshore reefs. Here, we present preliminary results from the first palaeoecological study of foraminiferal assemblages of nearshore reefs on the central GBR. Cores were recovered from the nearshore reef complex at Paluma Shoals using percussion techniques. Recovery was 100%, capturing the entire Holocene reef sequence of the selected reef structures. Radiocarbon dating and subsequent age-depth modelling techniques were used to identify reef sequences pre-dating European settlement. Benthic foraminifera assemblages were reconstructed from the identified sequences to establish pre-European ecological baselines with the aim of providing a record of foraminiferal distribution during vertical reef accretion and against which contemporary ecological change may be assessed.

  7. Roller bearing geometry design

    Science.gov (United States)

    Savage, M.; Pinkston, B. H. W.

    1976-01-01

    A theory of kinematic stabilization of rolling cylinders is extended and applied to the design of cylindrical roller bearings. The kinematic stabilization mechanism puts a reverse skew into the rolling elements by changing the roller taper. Twelve basic bearing modification designs are identified amd modeled. Four have single transverse convex curvature in their rollers while eight have rollers which have compound transverse curvature made up of a central cylindrical band surrounded by symmetric bands with slope and transverse curvature. The bearing designs are modeled for restoring torque per unit axial displacement, contact stress capacity, and contact area including dynamic loading, misalignment sensitivity and roller proportion. Design programs are available which size the single transverse curvature roller designs for a series of roller slopes and load separations and which design the compound roller bearings for a series of slopes and transverse radii of curvature. The compound rollers are proportioned to have equal contact stresses and minimum size. Design examples are also given.

  8. DW_BEAR

    Data.gov (United States)

    Department of Homeland Security — Subset of BEAR (Bi-Weekly Examination Analysis and Reporting) data used for financial audit remediation reporting within the Coast Guard Business Intelligence (CGBI)...

  9. Rolling bearing analysis

    CERN Document Server

    Harris, Tedric A

    2001-01-01

    One of the most well-known experts in the field brings cutting-edge research to practitioners in the new edition of this important reference. Covers the improved mathematical calculations for rolling bearing endurance developed by the American Society of Mechanical Engineers and the Society of Lubrication and Tribology Engineers. Updated with new material on Condition-Based Maintenance, new testing methods, and new bearing materials.

  10. Gear bearing drive

    Science.gov (United States)

    Mavroidis, Constantinos (Inventor); Vranish, John M. (Inventor); Weinberg, Brian (Inventor)

    2011-01-01

    A gear bearing drive provides a compact mechanism that operates as an actuator providing torque and as a joint providing support. The drive includes a gear arrangement integrating an external rotor DC motor within a sun gear. Locking surfaces maintain the components of the drive in alignment and provide support for axial loads and moments. The gear bearing drive has a variety of applications, including as a joint in robotic arms and prosthetic limbs.

  11. Load responsive hydrodynamic bearing

    Science.gov (United States)

    Kalsi, Manmohan S.; Somogyi, Dezso; Dietle, Lannie L.

    2002-01-01

    A load responsive hydrodynamic bearing is provided in the form of a thrust bearing or journal bearing for supporting, guiding and lubricating a relatively rotatable member to minimize wear thereof responsive to relative rotation under severe load. In the space between spaced relatively rotatable members and in the presence of a liquid or grease lubricant, one or more continuous ring shaped integral generally circular bearing bodies each define at least one dynamic surface and a plurality of support regions. Each of the support regions defines a static surface which is oriented in generally opposed relation with the dynamic surface for contact with one of the relatively rotatable members. A plurality of flexing regions are defined by the generally circular body of the bearing and are integral with and located between adjacent support regions. Each of the flexing regions has a first beam-like element being connected by an integral flexible hinge with one of the support regions and a second beam-like element having an integral flexible hinge connection with an adjacent support region. A least one local weakening geometry of the flexing region is located intermediate the first and second beam-like elements. In response to application of load from one of the relatively rotatable elements to the bearing, the beam-like elements and the local weakening geometry become flexed, causing the dynamic surface to deform and establish a hydrodynamic geometry for wedging lubricant into the dynamic interface.

  12. Variability of the planktonic foraminifera community across the Eocene/Oligocene boundary, Fuente Caldera Section, Baetic Ranges (Spain)

    Science.gov (United States)

    Legarda-Lisarri, A.

    2013-12-01

    During the Eocene/Oligocene transition, in a massive extinction event that took place about 33.7 million years ago, the current high resolution study analyzes qualitatively and quantitatively the community structure of the planktonic foraminifera that were preserved in the hemipelagic sediments of the Tethys Sea. The sampled section of the Fuente Caldera column, located in the Baetic mountain ranges, spans a register of 396,551.7 years. Based in the identification of 27 species, that belong to 13 genera and 2 families of foraminifera, there have been found three biozones of Gonzalvo Zonation (Gonzalvo, 2002) in the studied stratigraphic interval: Turborotalia cocoaensis and Cribrohantkenina lazzarii Biozones (Rupelian), and Paragloborotalia increbescens (Priabonian). The planktonic foraminifera associations variability patterns are defined by paleoecologic indexes (diversity index, high and low latitude species index and planktonic and benthic foraminifera index), by geochemical proxies: δ18O and δ13C and by 'Q' Mode Factor Analysis. They prove that the deposition environment is outer platform and also, they suggest that the studied area in the Tethys Sea underwent many thermal pulses, during which some species extinct or appear. In the first extinction event the species Turborotalia cocoaensis and Turborotalia cunialensis became extinct. In the second one, Hantkenina alabamensis, Hantkenina brevispina, Cribrohantkenina lazzarii and Pseudohastigerina micra became extinct while a succession occured; Globigerina officinalis, Globoturborotalita anguliofficinalis and Tenuitellinata angustiumbilicata appeared. The cooling event that finished in the Lower Oligocene was the biggest of these pulses, which was extremely abrupt and corresponds to the Oi-1 event that was described by Miller (Miller, 1991). All this evidences that the planktonic foraminifera extinction in the Upper Eocene was a gradual and fast event, what is supported by the Factor Analysis application. Key

  13. Eocene sea temperatures for the mid-latitude southwest Pacific from Mg/Ca ratios in planktonic and benthic foraminifera

    Science.gov (United States)

    Creech, John B.; Baker, Joel A.; Hollis, Christopher J.; Morgans, Hugh E. G.; Smith, Euan G. C.

    2010-11-01

    We have used laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) to measure elemental (Mg/Ca, Al/Ca, Mn/Ca, Zn/Ca, Sr/Ca, and Ba/Ca) ratios of 13 species of variably preserved early to middle Eocene planktonic and benthic foraminifera from New Zealand. The foraminifera were obtained from Ashley Mudstone, mid-Waipara River, South Island, which was deposited at bathyal depth ( ca. 1000 m) on the northern margin of the east-facing Canterbury Basin at a paleo-latitude of ca. 55°S. LA-ICP-MS data yield trace element depth profiles through foraminifera test walls that can be used to identify and exclude zones of surficial contamination and infilling material resulting from diagenetic coatings, mineralisation and detrital sediment. Screened Mg/Ca ratios from 5 species of foraminifera are used to calculate sea temperatures from late Early to early Middle Eocene ( ca. 51 to 46.5 Ma), a time interval that spans the termination of the Early Eocene Climatic Optimum (EECO). During this time, sea surface temperatures (SST) varied from 30 to 24 °C, and bottom water temperatures (BWT) from 21 to 14 °C. Comparison of Mg/Ca sea temperatures with published δ 18O and TEX 86 temperature data from the same samples (Hollis et al., 2009) shows close correspondence, indicating that LA-ICP-MS can provide reliable Mg/Ca sea temperatures even where foraminiferal test preservation is variable. Agreement between the three proxies also implies that Mg/Ca-temperature calibrations for modern planktonic and benthic foraminifera can generally be applied to Eocene species, although some species (e.g., V. marshalli) show significant calibration differences. The Mg/Ca ratio of the Eocene ocean is constrained by our data to be 35-50% lower than the modern ocean depending on which TEX 86 - temperature calibration (Kim et al., 2008; Liu et al., 2009) - is used to compare with the Mg/Ca sea temperatures. Sea temperatures derived from δ 18O analysis of foraminifera from Waipara show

  14. Constraining Seasonal and Vertical Distributions of Planktonic Foraminifera for Paleoclimate Reconstruction Since MIS3 at the Axial Seamount, Juan de Fuca Ridge

    Science.gov (United States)

    Chen, S. L.; Ravelo, A. C.; Clague, D. A.

    2015-12-01

    The California Current is an upwelling region with dynamic interactions between circulation, biological productivity and ecology. A 77 cm piston push core was taken from the Juan de Fuca Ridge Axial Seamount using a Remotely Operated Vehicle (ROV) (2213m, 45.55º N, 130.08º W), an active submarine volcano ~480 km off Oregon's coast. Five radiocarbon dates indicate that the sediment ranges from 42.6 ka at 77 cm to 17.6 ka at 15 cm, with an average sediment accumulation rate of 2.47 cm/ka from 77-15 cm, and an average rate of 0.85 cm/ka during the postglacial period (the core representing subtropical, subartic, and arctic fauna have been used to constrain changes in vertical and seasonal temperature since Marine Isotope Stage 3 (MIS3). Measurements of δ18O of the upwelling species Globigerina bulloides, the thermocline dwelling species Neogloboquadrina dutertrei, and the warm mixed-layer species Orbulina universa are offset from each other, reflecting vertical and seasonal variation among the planktonic foraminifera. Of the three species, G. bulloides shows the least variation in δ18O, possibly indicating that marked changes in temperature are masking changes in the δ18O of seawater due to global ice volume changes. G. bulloides and O. universa δ18O values are similar in MIS 3 and diverge with time, indicating the development of strong seasonal succession of species, since the last glacial maximum. Bulk nitrogen isotopes and nitrogen flux provide additional constraints on upwelling strength and insight into local biological productivity and nutrient dynamics. Obtaining Mg/Ca data will clarify the δ 18O interpretation except deep in the core where metal-bearing authigenic precipitates affect Mg concentrations. These climatic proxies together provide insight into how global climate change and local seamount volcanism impacts regional productivity in the California Current.

  15. Climate Drives Polar Bear Origins

    Science.gov (United States)

    In their provocative analysis of northern bears (“Nuclear genomic sequences reveal that polar bears are an old and distinct bear lineage,” Reports, 20 April, p. 344), F. Hailer et al. use independent nuclear loci to show that polar bears originated during the middle Pleistocene, rather than during t...

  16. Watchable Wildlife: The Black Bear

    Science.gov (United States)

    Lynn L. Rogers

    1992-01-01

    Black bears are the bears people most often encounter. Black bears live in forests over much of North America, unlike grizzlies that live only in Alaska, northern and western Canada, and the northern Rocky Mountains. This brochure presents the latest information on black bear life and how this species responds to an ever-increasing number of campers, hikers, and...

  17. Tribology of alternative bearings.

    Science.gov (United States)

    Fisher, John; Jin, Zhongmin; Tipper, Joanne; Stone, Martin; Ingham, Eileen

    2006-12-01

    The tribological performance and biological activity of the wear debris produced has been compared for highly cross-linked polyethylene, ceramic-on-ceramic, metal-on-metal, and modified metal bearings in a series of in vitro studies from a single laboratory. The functional lifetime demand of young and active patients is 10-fold greater than the estimated functional lifetime of traditional polyethylene. There is considerable interest in using larger diameter heads in these high demand patients. Highly cross-linked polyethylene show a four-fold reduction in functional biological activity. Ceramic-on-ceramic bearings have the lowest wear rates and least reactive wear debris. The functional biological activity is 20-fold lower than with highly cross-linked polyethylene. Hence, ceramic-on-ceramic bearings address the tribological lifetime demand of highly active patients. Metal-on-metal bearings have substantially lower wear rates than highly cross-linked polyethylene and wear decreases with head diameter. Bedding in wear is also lower with reduced radial clearance. Differential hardness ceramic-on-metal bearings and the application of ceramic-like coatings reduce metal wear and ion levels.

  18. The morphogroups of small agglutinated foraminifera from the Devonian carbonate complex of the Prague Synform, (Barrandian area, Czech Republic)

    Czech Academy of Sciences Publication Activity Database

    Holcová, K.; Slavík, Ladislav

    2013-01-01

    Roč. 386, č. 5 (2013), s. 210-214 ISSN 0031-0182 Grant - others:Rada Programu interní podpory projektů mezinárodní spolupráce AV ČR(CZ) M100131201 Institutional support: RVO:67985831 Keywords : Barrandian area * Early Devonian * foraminifera * morphogroups Subject RIV: DB - Geology ; Mineralogy Impact factor: 2.752, year: 2013

  19. Selandian-Thanetian larger foraminifera from the lower Jafnayn Formation in the Sayq area (eastern Oman Mountains)

    Energy Technology Data Exchange (ETDEWEB)

    Serra-Kiel, J.; Vicedo, V.; Razin, P.; Grelaud, C.

    2016-07-01

    The larger foraminifera of the lower part of the Jafnayn Formation outcropping in the Wadi Sayq, in the Paleocene series of the eastern Oman Mountains, have been studied and described in detail. The analysis have allowed us to develop a detailed systematic description of each taxa, constraining their biostratigraphic distribution and defining the associated foraminifera assemblages. The taxonomic study has permitted us to identify each morphotype precisely and describe three new taxa, namely, Ercumentina sayqensis n. gen. n. sp. Lacazinella rogeri n. sp. and Globoreticulinidae new family. The first assemblage is characterized by the presence of Coskinon sp., Dictyoconus cf. turriculus Hottinger and Drobne, Anatoliella ozalpiensis Sirel, Ercumentina sayqensis n. gen. n. sp. SerraKiel and Vicedo, Lacazinella rogeri n. sp. Serra-Kiel and Vicedo, Mandanella cf. flabelliformis Rahaghi, Azzarolina daviesi (Henson), Lockhartia retiata Sander, Dictyokathina simplex Smout and Miscellanites globularis (Rahaghi). The second assemblage is constituted by the forms Pseudofallotella persica (Hottinger and Drobne), Dictyoconus cf. turriculus Hottinger and Drobne, Lacazinella rogeri n. sp. Serra-Kiel and Vicedo, Azzarolina daviesi (Henson), Keramosphera? cf. iranica Rahaghi, Lockhartia haimei (Davies), Lockhartia retiata Sander, Sakesaria trichilata Sander, Kathina delseota Smout, Elazigina harabekayisensis Sirel, Daviesina khatiyahi Smout, and Miscellanea juliettae Leppig. The first assemblage can be considered to belong to the Shallow Bentic Zone SBZ2 (early Selandian age), and the second assemblage to the SBZ3 (late Selandian-early Thanetian age).This paper shows, for the first time in the Middle East area, a correlation between the Selandian larger foraminifera and planktonic foraminifera biozones. (Author)

  20. Selandian-Thanetian larger foraminifera from the lower Jafnayn Formation in the Sayq area (eastern Oman Mountains)

    International Nuclear Information System (INIS)

    Serra-Kiel, J.; Vicedo, V.; Razin, P.; Grelaud, C.

    2016-01-01

    The larger foraminifera of the lower part of the Jafnayn Formation outcropping in the Wadi Sayq, in the Paleocene series of the eastern Oman Mountains, have been studied and described in detail. The analysis have allowed us to develop a detailed systematic description of each taxa, constraining their biostratigraphic distribution and defining the associated foraminifera assemblages. The taxonomic study has permitted us to identify each morphotype precisely and describe three new taxa, namely, Ercumentina sayqensis n. gen. n. sp. Lacazinella rogeri n. sp. and Globoreticulinidae new family. The first assemblage is characterized by the presence of Coskinon sp., Dictyoconus cf. turriculus Hottinger and Drobne, Anatoliella ozalpiensis Sirel, Ercumentina sayqensis n. gen. n. sp. SerraKiel and Vicedo, Lacazinella rogeri n. sp. Serra-Kiel and Vicedo, Mandanella cf. flabelliformis Rahaghi, Azzarolina daviesi (Henson), Lockhartia retiata Sander, Dictyokathina simplex Smout and Miscellanites globularis (Rahaghi). The second assemblage is constituted by the forms Pseudofallotella persica (Hottinger and Drobne), Dictyoconus cf. turriculus Hottinger and Drobne, Lacazinella rogeri n. sp. Serra-Kiel and Vicedo, Azzarolina daviesi (Henson), Keramosphera? cf. iranica Rahaghi, Lockhartia haimei (Davies), Lockhartia retiata Sander, Sakesaria trichilata Sander, Kathina delseota Smout, Elazigina harabekayisensis Sirel, Daviesina khatiyahi Smout, and Miscellanea juliettae Leppig. The first assemblage can be considered to belong to the Shallow Bentic Zone SBZ2 (early Selandian age), and the second assemblage to the SBZ3 (late Selandian-early Thanetian age).This paper shows, for the first time in the Middle East area, a correlation between the Selandian larger foraminifera and planktonic foraminifera biozones. (Author)

  1. Incorporation of Mg and Sr in calcite of cultured benthic foraminifera: impact of calcium concentration and associated calcite saturation state

    Directory of Open Access Journals (Sweden)

    M. Raitzsch

    2010-03-01

    Full Text Available We investigated the effect of the calcium concentration in seawater and thereby the calcite saturation state (Ω on the magnesium and strontium incorporation into benthic foraminiferal calcite under laboratory conditions. For this purpose individuals of the shallow-water species Heterostegina depressa (precipitating high-Mg calcite, symbiont-bearing and Ammonia tepida (low-Mg calcite, symbiont-barren were cultured in media under a range of [Ca2+], but similar Mg/Ca ratios. Trace element/Ca ratios of newly formed calcite were analysed with Laser Ablation Inductively Coupled Plasma Mass Spectrometry (LA-ICP-MS and normalized to the seawater elemental composition using the equation DTE=(TE/Cacalcite/(TE/Caseawater. The culturing study shows that DMg of A. tepida significantly decreases with increasing Ω at a gradient of −4.3×10−5 per Ω unit. The DSr value of A. tepida does not change with Ω, suggesting that fossil Sr/Ca in this species may be a potential tool to reconstruct past variations in seawater Sr/Ca. Conversely, DMg of H. depressa shows only a minor decrease with increasing Ω, while DSr increases considerably with Ω at a gradient of 0.009 per Ω unit. The different responses to seawater chemistry of the two species may be explained by a difference in the calcification pathway that is, at the same time, responsible for the variation in the total Mg incorporation between the two species. Since the Mg/Ca ratio in H. depressa is 50–100 times higher than that of A. tepida, it is suggested that the latter exhibits a mechanism that decreases the Mg/Ca ratio of the calcification fluid, while the high-Mg calcite forming species may not have this physiological tool. If the dependency of Mg incorporation on seawater [Ca2+] is also valid for deep

  2. Partial tooth gear bearings

    Science.gov (United States)

    Vranish, John M. (Inventor)

    2010-01-01

    A partial gear bearing including an upper half, comprising peak partial teeth, and a lower, or bottom, half, comprising valley partial teeth. The upper half also has an integrated roller section between each of the peak partial teeth with a radius equal to the gear pitch radius of the radially outwardly extending peak partial teeth. Conversely, the lower half has an integrated roller section between each of the valley half teeth with a radius also equal to the gear pitch radius of the peak partial teeth. The valley partial teeth extend radially inwardly from its roller section. The peak and valley partial teeth are exactly out of phase with each other, as are the roller sections of the upper and lower halves. Essentially, the end roller bearing of the typical gear bearing has been integrated into the normal gear tooth pattern.

  3. Effect of ocean acidification on the benthic foraminifera Ammonia sp. is caused by a decrease in carbonate ion concentration

    Directory of Open Access Journals (Sweden)

    N. Keul

    2013-10-01

    Full Text Available About 30% of the anthropogenically released CO2 is taken up by the oceans; such uptake causes surface ocean pH to decrease and is commonly referred to as ocean acidification (OA. Foraminifera are one of the most abundant groups of marine calcifiers, estimated to precipitate ca. 50 % of biogenic calcium carbonate in the open oceans. We have compiled the state of the art literature on OA effects on foraminifera, because the majority of OA research on this group was published within the last three years. Disparate responses of this important group of marine calcifiers to OA were reported, highlighting the importance of a process-based understanding of OA effects on foraminifera. We cultured the benthic foraminifer Ammonia sp. under a range of carbonate chemistry manipulation treatments to identify the parameter of the carbonate system causing the observed effects. This parameter identification is the first step towards a process-based understanding. We argue that [CO32−] is the parameter affecting foraminiferal size-normalized weights (SNWs and growth rates. Based on the presented data, we can confirm the strong potential of Ammonia sp. foraminiferal SNW as a [CO32−] proxy.

  4. Biocenoses of benthic foraminifera of the Aveiro Continental Shelf (Portugal: influence of the upwelling events and other shelf processes

    Directory of Open Access Journals (Sweden)

    Maria Virgínia Alves Martins

    2017-03-01

    Full Text Available This work aims to compare the dimensions and composition of benthic foraminiferal biocenoses (living specimens during two summer sampling events. Forty-four sediment samples were collected on the Aveiro Continental Shelf (Center of Portugal (latitude of 40º30'N-40º50'N, longitude of 8º46'W-9º20'W for granulometry, total organic matter (TOM and living foraminiferal analyses. The sediment samples were collected during summers of 1994 and 1995, on stations located along transects (east-west direction and between the bathymetries of 10-200 m. During the sampling campaigns, measurements of salinity, temperature and density data were recorded in the water column. The results showed that the living assemblages were mainly found in stations located between 20-80 m depth. The abundance of living foraminifera was generally reduced at depths <20 m in the so-called “coastal deposits”, where the sediments are frequently remobilized and transported by the littoral drift. Living benthic foraminiferal densities were also reduced in stations at 80-200 m depth, despite the high sedimentary TOM contents. Results obtained in this work indicate that, in this marine setting, the most determinant factors for the dimension and composition of living foraminifera are not the sediments’ granulometry and organic matter content. In fact, the coastal dynamics, sediment stability, availability of quality food, among other factors, such as the bottom salinity oscillations and their combination, should better explain the abundance of living foraminifera and the biocenoses composition.

  5. Marine ecology conditions at Weda Bay, North Maluku based on statistical analysis on distribution of recent foraminifera

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    Kurniasih Anis

    2017-01-01

    Full Text Available Analysis of foraminifera in geology,usually being used to find the age of rocks/ sediments and depositional environment. In this study, recent foraminifera was used not only to determinethe sedimentary environment,but also to estimate the ecological condition of the water through a statistical approach.Analysis was performed quantitatively in 10 surface seabed sediment samples in Weda Bay North Maluku. The analysis includes dominance (Sympson Index, diversity and evenness (Shannon Index, and the ratio of planktonic -benthic. The results were shown in the plotting diagram of M-R-T (Miliolid-Rotalid-Textularid to determine the depositional environment. Quantitative analysis was performed using Past software (paleontological version Statistic 1:29.The analysis result showed there was no domination of certain taxon with a moderate degree of evenness and stable communities and considerably a moderate diversity. The results of this analysis indicated that research area had a stable water conditions with the optimum level of carbonate content, oxygen supply, salinity, and temperature. The ratio of planktonic and benthic indicate the relative depth, which was deeper the water increased the percentage of planktonic foraminifera. Based on M-R-T diagram showed the distribution of sediment deposited on exposed carbonate (carbonate platform environment with normal saline.

  6. Late Neogene foraminifera from the northern Namibian continental shelf and the transition to the Benguela Upwelling System

    Science.gov (United States)

    Bergh, Eugene W.; Compton, John S.; Frenzel, Peter

    2018-05-01

    Middle Miocene to Plio-Pleistocene foraminifera provide insights into the palaeoenvironment on the northern Namibian continental shelf located at the far northern end of the present-day Benguela Upwelling System (BUS). Biostratigraphy and Strontium Isotope Stratigraphy (SIS) of the recovered basal olive-green mud unit indicate an age of 16 to 14 Ma. A sharp, erosional contact separates the basal mud from the overlying Plio-Pleistocene gravelly pelletal phosphorite sands. Grain size data, P/B ratios and benthic diversity indices indicate a change between the middle Miocene and overlying Plio-Pleistocene palaeoenvironments linked to the timing and conditions associated with the initiation of the BUS. The different lithological units and microfossil assemblages in the olive-green mud unit and the overlying pelletal phosphorite units support the late Miocene initiation of the BUS and the northwards migration of the Angola-Benguela Front. Planktic foraminifera indicate a shift from warmer surface water conditions to cooler conditions during the initiation of the BUS. Benthic palaeobathymetric ranges and P/B ratios are consistent with outer shelf water depths suggesting a deeper palaeoenvironment during the Mid-Miocene Climatic Optimum (MMCO) than today. Benthic foraminifera in the middle Miocene are dominated by large (>1 mm) taxa and adapted to oligotrophic environments before the initiation of the BUS. The benthic assemblage composition indicates that bottom water conditions changed to eutrophic conditions during the Plio-Pleistocene under intensified upwelling conditions.

  7. Benthic Foraminifera and Bacterial Activity as a Proxy for Environmental Characterization in Potengi Estuary, Rio Grande do Norte, Brazil

    Directory of Open Access Journals (Sweden)

    Frederico S. da Silva

    2010-01-01

    Full Text Available The aim of this study was to identify possible zonation patterns and assess the environmental impact on the Potengi River Estuary, Rio Grande do Norte State, through the distribution of benthic foraminifera associated to bacterial activity and abiotic parameters. Six sediment samples were collected from locations that presented clear signs of pollution. The environment was predominantly anaerobic and fermentation occurred at all sites. Forty-two species of foraminifera were identified. The dominant species were Ammonia tepida and Arenoparrella mexicana, which are known to be opportunistic, and able to adapt to rapidly changing conditions. CCA analyses showed that salinity and organic matter, followed by bacterial carbon, were more strongly linked to organism distribution in the Potengi River Estuary. Dissolved oxygen concentration, temperature and total organic matter were higher at the estuary mouth than at the other sites, creating favorable conditions for foraminiferal growth and allowing the faunistic succession on the upper estuary. As foraminifera assemblages when associated to environmental parameters can be used as efficient proxies for environmental diagnosis, these results suggest that the Potengi Estuary is under great stress from the surrounding urban development.

  8. The long way of planktonic Foraminifera from biostratigraphy to paleoceanography (Jean Baptiste Lamarck Medal Lecture)

    Science.gov (United States)

    Premoli Silva, Isabella

    2014-05-01

    The mid of the last century was a time of flourishing studies concerning the importance of planktonic foraminifera in precisely dating and correlating sedimentary successions after the publication of the first biostratigraphic schemes provided by the Suisse Group (i.e. Kugler, Bolli, Broennimann) from the Caribbean region and former Southern USSR (Subbotina). Soon after Bolli's Trinidad scheme was widespread, planktonic foraminiferal distribution from Upper Cretaceous to Miocene was investigated intensively for dating the Neogene stratotypes, whose identifications were mainly based on poorly age-diagnostic, facies-controlled macrofossils, and for calibrating Paleogene larger foraminiferal distributions. Since these early works planktonic foraminiferal biostratigraphy was continously ameliorated, extended in time from Early Cretaceous to Recent by several authors and from different settings and domains, reaching progressively the current higher resolution, now calibrated to calcareous nannofossil distributions. To be mentioned, the detailed biostratigraphic studies on the Gubbio section (central Italy) provided (1) the first carefull documentation of the mass extinction of Cretaceous planktonic foraminifera, the presence of tiny Cretaceous survivors, and the rapid recovery of Danian assemblages, and (2) the first calibration of the Upper Cretaceous to Eocene reversal polarity scale in which the K/Pg boundary was demonstrated to fall within the magnetic reversal C29r. A major step forward was the recovery, since 1968, of several thousand of cores from over 1000 holes drilled in all oceans by the DSDP, ODP and IODP projects. The recovery of deep-sea sediments from all latitudes opened a new research field, the paleoceanography. Based on the large knowledge acquired on modern organisms in the '60s, for the Paleogene and Cretaceous reconstructions we started from the assumption that these extinct organisms lived in the water column like their modern counterpart and were

  9. ENSO activity during the last climate cycle using Individual Foraminifera Analysis

    Science.gov (United States)

    Leduc, G.; Vidal, L.; Thirumalai, K.

    2017-12-01

    The El Niño / Southern Oscillation (ENSO) is the principal mode of interannual climate variability and affects key climate parameters such as low-latitude rainfall variability. Recent climate modeling experiments tend to suggest an increase in the frequency of both El Niño and La Niña events in the future, but these results remain model-dependent and require to be validated by paleodata-model comparisons. Fossil corals indicate that the ENSO variance during the 20th century is particularly high as compared to other time periods of the Holocene. Beyond the Holocene, however, little is known on past ENSO changes, which makes difficult to test paleoclimate model simulations that are used to study the ENSO sensitivity to various types of forcings. We have expanded an Individual Foraminifera Analysis (IFA) dataset using the thermocline-dwelling N. dutertrei on a marine core collected in the Panama Basin (Leduc et al., 2009), that has proven to be a skillful way to reconstruct the ENSO (Thirumalai et al., 2013). Our new IFA dataset comprehensively covers the Holocene, allowing to verify how the IFA method compares with ENSO reconstructions using corals. The dataset then extends back in time to Marine Isotope Stage 6 (MIS), with a special focus the last deglaciation and Termination II (MIS5/6) time windows, as well as key time periods to tests the sensitivity of ENSO to ice volume and orbital parameters. The new dataset confirms variable ENSO activity during the Holocene and weaker activity during LGM than during the Holocene, as a recent isotope-enabled climate model simulations of the LGM suggests (Zhu et al., 2017). Such pattern is reproduced for the Termination II. Leduc, G., L. Vidal, O. Cartapanis, and E. Bard (2009), Modes of eastern equatorial Pacific thermocline variability: Implications for ENSO dynamics over the last glacial period, Paleoceanography, 24, PA3202, doi:10.1029/2008PA001701. Thirumalai, K., J. W. Partin, C. S. Jackson, and T. M. Quinn (2013

  10. Anthropogenic infilling of a Bermudian sinkhole and its impact on sedimentation and benthic foraminifera in the adjacent anchialine cave environment

    Directory of Open Access Journals (Sweden)

    Jacquelyn N. Cresswell

    2017-09-01

    Full Text Available In the mid-20th century, an inland brackish pond from Bermuda, known as Eve’s Pond, was filled with marine sediment from an adjacent coastal lagoon. At this time, an eyewitness reported “…sediment billowing out of the Green Bay Cave for days…”, which is a marine-dominated anchialine cave located proximal to the former location of Eve’s Pond (~200 m. The purpose of this study was to evaluate the potential impact of this infilling event on cave sedimentation and benthic meiofaunal communities, as proxied by the unicellular protists foraminifera that remain preserved in the sediment record. Eight sediment cores were collected from an underwater passage in Green Bay Cave in a transect towards the location where Eve’s Pond was surveyed in 1901 CE. The sediment cores were analyzed for visual and density changes (photography, X-radiography, textural variability, benthic foraminifera fauna and diversity, and radiocarbon dating. The recovered sediment cores mostly sampled a late Holocene carbonate mud facies that had been described during previous research in the cave, with benthic foraminiferal assemblages post-dating the onset of seawater circulating between the saline groundwater flooding the cave and the adjacent Harrington Sound ~1,900 years ago. However, two cores located further into the cave (cores 13 and 17 contain a carbonate sand layer with lagoon foraminifera that is anomalous with respect to the Holocene depositional history of the cave and is most likely related to the mid-20th century infilling of Eve’s Pond. Examination of these two cores showed that after the infilling event, the community of benthic foraminifera rapidly reverted to pre-impact assemblages with foraminiferal stygophiles (e.g., Spirophthalmidium emaciatum, Sigmoilina tenuis, which were not displaced by new colonizers introduced into the cave by the dredge spoils. We caution that the results cannot be extrapolated to the pelagic crustacean community, but the

  11. Magnetically leviated superconducting bearing

    Science.gov (United States)

    Weinberger, Bernard R.; Lynds, Jr., Lahmer

    1993-01-01

    A magnetically levitated superconducting bearing includes a magnet (2) mounted on a shaft (12) that is rotatable around an axis of rotation and a Type II superconductor (6) supported on a stator (14) in proximity to the magnet (2). The superconductor (6) is positioned so that when it is cooled to its superconducting state in the presence of a magnetic field, it interacts with the magnet (2) to produce an attractive force that levitates the magnet (2) and supports a load on the shaft (12). The interaction between the superconductor (6) and magnet(2) also produces surface screening currents (8) that generate a repulsive force perpendicular to the load. The bearing also has means for maintaining the superconductor at a temperature below its critical temperature (16, 18). The bearing could also be constructed so the magnet (2) is supported on the stator (14) and the superconductor (6) is mounted on the shaft (12). The bearing can be operated by cooling the superconductor (6) to its superconducting state in the presence of a magnetic field.

  12. Disruptive selection and bet-hedging in planktonic Foraminifera: Shell morphology as predictor of extinctions

    Directory of Open Access Journals (Sweden)

    Manuel F. G. Weinkauf

    2014-10-01

    Full Text Available Extinction is a remarkably difficult phenomenon to study under natural conditions. This is because the outcome of stress exposure and associated fitness reduction is not known until the extinction occurs and it remains unclear whether there is any phenotypic reaction of the exposed population that can be used to predict its fate. Here we take advantage of the fossil record, where the ecological outcome of stress exposure is known. Specifically, we analyze shell morphology of planktonic Foraminifera in sediment samples from the Mediterranean, during an interval preceding local extinctions. In two species representing different plankton habitats, we observe shifts in trait state and decrease in variance in association with non-terminal stress, indicating stabilizing selection. At terminal stress levels, immediately before extinction, we observe increased growth asymmetry and trait variance, indicating disruptive selection and bet-hedging. The pre-extinction populations of both species show a combination of trait states and trait variance distinct from all populations exposed to non-terminal levels of stress. This finding indicates that the phenotypic history of a population may allow the detection of threshold levels of stress, likely to lead to extinction. It is thus an alternative to population dynamics in studying and monitoring natural population ecology.

  13. Technical Note: On methodologies for determining the size-normalised weight of planktic foraminifera

    Directory of Open Access Journals (Sweden)

    C. J. Beer

    2010-07-01

    Full Text Available The size-normalised weight (SNW of planktic foraminifera, a measure of test wall thickness and density, is potentially a valuable palaeo-proxy for marine carbon chemistry. As increasing attention is given to developing this proxy it is important that methods are comparable between studies. Here, we compare SNW data generated using two different methods to account for variability in test size, namely (i the narrow (50 μm range sieve fraction method and (ii the individually measured test size method. Using specimens from the 200–250 μm sieve fraction range collected in multinet samples from the North Atlantic, we find that sieving does not constrain size sufficiently well to isolate changes in weight driven by variations in test wall thickness and density from those driven by size. We estimate that the SNW data produced as part of this study are associated with an uncertainty, or error bar, of about ±11%. Errors associated with the narrow sieve fraction method may be reduced by decreasing the size of the sieve window, by using larger tests and by increasing the number tests employed. In situations where numerous large tests are unavailable, however, substantial errors associated with this sieve method remain unavoidable. In such circumstances the individually measured test size method provides a better means for estimating SNW because, as our results show, this method isolates changes in weight driven by variations in test wall thickness and density from those driven by size.

  14. Environmental Quality Assessment of Bizerte Lagoon (Tunisia) Using Living Foraminifera Assemblages and a Multiproxy Approach

    Science.gov (United States)

    Alves Martins, Maria Virgínia; Zaaboub, Noureddine; Aleya, Lotfi; Frontalini, Fabrizio; Pereira, Egberto; Miranda, Paulo; Mane, Miguel; Rocha, Fernando; Laut, Lazaro; El Bour, Monia

    2015-01-01

    This study investigated the environmental quality of the Bizerte Lagoon (Tunisia) through an integrated approach that combined environmental, biogeochemical, and living benthic foraminiferal analyses. Specifically, we analyzed the physicochemical parameters of the water and sediment. The textural, mineralogical, and geochemical characteristics of the sediment, including total organic carbon, total nitrogen, simultaneously extracted metals (SEM), acid volatile sulfides (AVS), chlorophyll a, CaCO3, and changes in bacterial populations and carbon isotopes were measured. The SEM/AVS values indicated the presence of relatively high concentrations of toxic metals in only some areas. Foraminiferal assemblages were dominated by species such as A. parkinsoniana (20–91%), Bolivina striatula (coastal lagoons both in Mediterranean and northeast Atlantic regions. The results of this work suggest that Bizerte Lagoon is a unique setting. This lagoon is populated by typical marine species that invaded this ecosystem, attracted not only by the prevailing favorable environmental conditions but also by the abundance and quality of food. The results indicate that the metal pollution found in some areas have a negative impact on the assemblages of foraminifera. At present, however, this negative impact is not highly alarming. PMID:26372655

  15. Larger foraminifera of the Devil's Den and Blue Hole sinkholes, Florida

    Science.gov (United States)

    Cotton, Laura J.; Eder, Wolfgang; Floyd, James

    2018-03-01

    Shallow-water carbonate deposits are well-known from the Eocene of the US Gulf Coast and Caribbean. These deposits frequently contain abundant larger benthic foraminifera (LBF). However, whilst integrated stratigraphic studies have helped to refine the timing of LBF overturning events within the Tethys and Indo-Pacific regions with respect to global bio- and chemo-stratigraphic records, little recent work has been carried out in the Americas. The American LBF assemblages are distinctly different from those of Europe and the Indo-Pacific. It is therefore essential that the American bio-province is included in studies of LBF evolution, biodiversity and climate events to understand these processes on a global scale.Here we present the LBF ranges from two previously unpublished sections spanning 35 and 29 m of the upper Eocene Ocala limestone, as the early stages of a larger project addressing the taxonomy and biostratigraphy of the LBF of Florida. The study indicates that the lower member of the Ocala limestone may be Bartonian rather than Priabonian in age, with implications for the biostratigraphy of the region. In addition, the study highlights the need for multiple sites to assess the LBF assemblages and fully constrain ranges across Florida and the US Gulf and suggests potential LBF events for future integrated stratigraphic study.

  16. Magnitude of the Suess Effect in North Atlantic - a Study of Foraminifera and Transient Tracer Simulations

    Science.gov (United States)

    Zhou, Y.; Oppo, D.; Gebbie, G.; Thornalley, D. J.

    2016-02-01

    The Suess Effect is the decrease of δ 13C in the atmosphere due to the burning of fossil fuels. The recent decrease in δ 13C in the deep sea due to uptake of carbon has been measured in samples taken on hydrographic surveys, although these surveys only provide snapshots of deep sea δ 13C. The long-term decrease in δ 13C has been estimated using modern hydrographic properties, but there are no direct measurements. Here we present records of δ 13C from benthic and planktonic foraminifera, collected south of Iceland in the North Atlantic Ocean. The cores have high accumulation rates and, based on radiocarbon, modern core tops. We find a monotonic decreasing trend since 1850 that is significant in two out of the three benthic records we have generated. A tracer simulation, with Transit Time Distribution and Equilibrium Time Distribution generated from previous tracer modeling studies, predicts a trend that is similar to our observations at the core sites. The presence of the Suess Effect in some of the cores is consistent with previous estimates on the uptake of anthropogenic CO{}2 in the newly formed North Atlantic Deep Water.

  17. Global latitudinal species diversity gradient in deep-sea benthic foraminifera

    Science.gov (United States)

    Culver, Stephen J.; Buzas, Martin A.

    2000-02-01

    Global scale patterns of species diversity for modern deep-sea benthic foraminifera, an important component of the bathyal and abyssal meiofauna, are examined using comparable data from five studies in the Atlantic, ranging over 138° of latitude from the Norwegian Sea to the Weddell Sea. We show that a pattern of decreasing diversity with increasing latitude characterises both the North and South Atlantic. This pattern is confirmed for the northern hemisphere by independent data from the west-central North Atlantic and the Arctic basin. Species diversity in the North Atlantic northwards from the equator is variable until a sharp fall in the Norwegian Sea (ca. 65°N). In the South Atlantic species diversity drops from a maximum in latitudes less than 30°S and then decreases slightly from 40 to 70°S. For any given latitude, North Atlantic diversity is generally lower than in the South Atlantic. Both ecological and historical factors related to food supply are invoked to explain the formation and maintenance of the latitudinal gradient of deep-sea benthic foraminiferal species diversity. The gradient formed some 36 million years ago when global climatic cooling led to seasonally fluctuating food supply in higher latitudes.

  18. Environmental Quality Assessment of Bizerte Lagoon (Tunisia Using Living Foraminifera Assemblages and a Multiproxy Approach.

    Directory of Open Access Journals (Sweden)

    Maria Virgínia Alves Martins

    Full Text Available This study investigated the environmental quality of the Bizerte Lagoon (Tunisia through an integrated approach that combined environmental, biogeochemical, and living benthic foraminiferal analyses. Specifically, we analyzed the physicochemical parameters of the water and sediment. The textural, mineralogical, and geochemical characteristics of the sediment, including total organic carbon, total nitrogen, simultaneously extracted metals (SEM, acid volatile sulfides (AVS, chlorophyll a, CaCO3, and changes in bacterial populations and carbon isotopes were measured. The SEM/AVS values indicated the presence of relatively high concentrations of toxic metals in only some areas. Foraminiferal assemblages were dominated by species such as A. parkinsoniana (20-91%, Bolivina striatula (<40%, Hopkinsina atlantica (<17%, and Bolivina ordinaria (<15% that cannot be considered typical of impacted coastal lagoons both in Mediterranean and northeast Atlantic regions. The results of this work suggest that Bizerte Lagoon is a unique setting. This lagoon is populated by typical marine species that invaded this ecosystem, attracted not only by the prevailing favorable environmental conditions but also by the abundance and quality of food. The results indicate that the metal pollution found in some areas have a negative impact on the assemblages of foraminifera. At present, however, this negative impact is not highly alarming.

  19. Agglutinated Foraminifera indicate a deep bottom current over the Hovgaard Ridge, West of Spitsbergen

    Science.gov (United States)

    Kaminski, Michael; Frank, Niessen

    2015-04-01

    The Hovgård Ridge is situated in Fram Strait, west of Spitsbergen. The ridge either represents a submerged fragment of continental crust or an upwarped fragmant of ocean crust within the Fram Strait. Its crest rises to a water depth of approx. 1170 m. During Expedition 87 of the Icebreaker POLARSTERN in August 2014, a sediment-echosounding profile was recorded and a boxcore station was collected from the crest of Hovgård Ridge at 1169 m water depth. The surficial sediment at this station consists of dark yellowish brown pebbly-sandy mud with a minor admixture of biogenic components in the coarse fraction. Patches of large tubular foraminifera and isolated pebbles were clearly visible on the sediment surface. The sediment surface of the boxcore was covered with patches of large (>1 mm diameter) large tubular astrorhizids belonging mostly to the species Astrorhiza crassatina Brady, with smaller numbers of Saccorhiza, Hyperammina, and Psammosiphonella. Non-tubular species consist mainly of opportunistic forms such as Psammosphaera and Reophax. The presence of large suspension-feeding tubular genera as well as opportunistic forms, as well as sediment winnowing, point to the presence of a deep current at this locality that is strong enough to disturb the benthic fauna. This is confirmed by data obtained from sediment echosounding, which exhibit lateral variation of relative sedimentation rates within the Pleistocene sedimentary drape covering the ridge indicative of winnowing in a south-easterly direction.

  20. A note on the Pavonina flabelliformis D'Orbigny (benthic foraminifera) from the Arabian Sea

    Digital Repository Service at National Institute of Oceanography (India)

    Khare, N.

    . flabelliformis in modern sediments off Karwar suggests and updates the lower depth limit to 33 metre as against reported from deeper regions in previous studies. This will have significant bearing in paleodepth studies of sedimentary strata having fossils...

  1. Actuators for Active Magnetic Bearings

    Directory of Open Access Journals (Sweden)

    Eric H. Maslen

    2017-10-01

    Full Text Available The literature of active magnetic bearing (AMB technology dates back to at least 1937 when the earliest work that clearly describes an active magnetic bearing system was published by Jesse Beams [...

  2. Delayed child-bearing.

    Science.gov (United States)

    Johnson, Jo-Ann; Tough, Suzanne

    2012-01-01

    To provide an overview of delayed child-bearing and to describe the implications for women and health care providers. Delayed child-bearing, which has increased greatly in recent decades, is associated with an increased risk of infertility, pregnancy complications, and adverse pregnancy outcome. This guideline provides information that will optimize the counselling and care of Canadian women with respect to their reproductive choices. Maternal age is the most important determinant of fertility, and obstetric and perinatal risks increase with maternal age. Many women are unaware of the success rates or limitations of assisted reproductive technology and of the increased medical risks of delayed child-bearing, including multiple births, preterm delivery, stillbirth, and Caesarean section. This guideline provides a framework to address these issues. Studies published between 2000 and August 2010 were retrieved through searches of PubMed and the Cochrane Library using appropriate key words (delayed child-bearing, deferred pregnancy, maternal age, assisted reproductive technology, infertility, and multiple births) and MeSH terms (maternal age, reproductive behaviour, fertility). The Internet was also searched using similar key words, and national and international medical specialty societies were searched for clinical practice guidelines and position statements. Data were extracted based on the aims, sample, authors, year, and results. The quality of evidence was rated using the criteria described in the Report of the Canadian Task Force on Preventive Health Care (Table 1). The Society of Obstetricians and Gynaecologists of Canada. RECOMMENDATIONS 1. Women who delay child-bearing are at increased risk of infertility. Prospective parents, especially women, should know that their fecundity and fertility begin to decline significantly after 32 years of age. Prospective parents should know that assisted reproductive technologies cannot guarantee a live birth or completely

  3. Government Risk-Bearing

    CERN Document Server

    1993-01-01

    The u.s. government bulks large in the nation's financial markets. The huge volume of government-issued and -sponsored debt affects the pricing and volume ofprivate debt and, consequently, resource allocation between competing alternatives. What is often not fully appreciated is the substantial influence the federal government wields overresource allocation through its provisionofcreditandrisk-bearing services to the private economy. Because peopleand firms generally seekto avoid risk, atsomeprice they are willing to pay another party to assume the risk they would otherwise face. Insurance companies are a class of private-sector firms one commonly thinks of as providing these services. As the federal government has expanded its presence in the U.S. economy during this century, it has increasingly developed programs aimed at bearing risks that the private sector either would not take on at any price, or would take on but atapricethoughtto besogreatthatmostpotentialbeneficiarieswouldnotpurchase the coverage. To...

  4. Passive magnetic bearing system

    Science.gov (United States)

    Post, Richard F.

    2014-09-02

    An axial stabilizer for the rotor of a magnetic bearing provides external control of stiffness through switching in external inductances. External control also allows the stabilizer to become a part of a passive/active magnetic bearing system that requires no external source of power and no position sensor. Stabilizers for displacements transverse to the axis of rotation are provided that require only a single cylindrical Halbach array in its operation, and thus are especially suited for use in high rotation speed applications, such as flywheel energy storage systems. The elimination of the need of an inner cylindrical array solves the difficult mechanical problem of supplying support against centrifugal forces for the magnets of that array. Compensation is provided for the temperature variation of the strength of the magnetic fields of the permanent magnets in the levitating magnet arrays.

  5. Stacked magnet superconducting bearing

    International Nuclear Information System (INIS)

    Rigney, T.K. II; Saville, M.P.

    1993-01-01

    A superconducting bearing is described, comprising: a plurality of permanent magnets magnetized end-to-end and stacked side-by-side in alternating polarity, such that flux lines flow between ends of adjacent magnets; isolating means, disposed between said adjacent magnets, for reducing flux leakage between opposing sides of said adjacent magnets; and a member made of superconducting material having at least one surface in communication with said flux lines

  6. Radium bearing waste disposal

    International Nuclear Information System (INIS)

    Tope, W.G.; Nixon, D.A.; Smith, M.L.; Stone, T.J.; Vogel, R.A.; Schofield, W.D.

    1995-01-01

    Fernald radium bearing ore residue waste, stored within Silos 1 and 2 (K-65) and Silo 3, will be vitrified for disposal at the Nevada Test Site (NTS). A comprehensive, parametric evaluation of waste form, packaging, and transportation alternatives was completed to identify the most cost-effective approach. The impacts of waste loading, waste form, regulatory requirements, NTS waste acceptance criteria, as-low-as-reasonably-achievable principles, and material handling costs were factored into the recommended approach

  7. Magnetic translator bearings

    Science.gov (United States)

    Hockney, Richard L. (Inventor); Downer, James R. (Inventor); Eisenhaure, David B. (Inventor); Hawkey, Timothy J. (Inventor); Johnson, Bruce G. (Inventor)

    1990-01-01

    A magnetic bearing system for enabling translational motion includes a carriage and a shaft for movably supporting the carriage; a first magnetic bearing fixed to one of the carriage and shaft and slidably received in a first channel of the other of the carriage and shaft. The first channel is generally U shaped with two side walls and a back wall. The magnetic bearing includes a pair of spaced magnetic pole pieces, each pole piece having a pair of electromagnetic coils mounted on poles on opposite ends of the pole piece proximate the side walls, and a third electromagnetic coil mounted on a pole of the pole piece proximate the backwall; a motion sensor for sensing translational motion along two axes and rotationally about three axes of the carriage and shaft relative to each other; and a correction circuit responsive to the sensor for generating a correction signal to drive the coils to compensate for any misalignment sensed between the carriage and the shaft.

  8. Bearing for liquid metal pump

    International Nuclear Information System (INIS)

    Dickinson, R.J.; Pennell, W.E.; Wasko, J.

    1984-01-01

    A liquid metal pump bearing support comprises a series of tangentially oriented spokes that connect the bearing cylinder to the pump internals structure. The spokes may be arranged in a plurality of planes extending from the bearing cylinder to the pump internals with the spokes in one plane being arranged alternately with those in the next plane. The bearing support structure provides the pump with sufficient lateral support for the bearing structure together with the capability of accommodating differential thermal expansion without adversely affecting pump performance

  9. Ground-truthing the Foraminifera-bound Nitrogen Isotope Paleo-proxy in the Modern Sargasso Sea

    Science.gov (United States)

    Smart, S.; Ren, H. A.; Fawcett, S. E.; Conte, M. H.; Rafter, P. A.; Ellis, K. K.; Weigand, M. A.; Sigman, D. M.

    2016-02-01

    We present the nitrogen isotope ratios (δ15N) of planktonic foraminifera, a type of calcifying zooplankton, collected from surface ocean net tows, moored sediment traps and core-top sediments at the Bermuda Atlantic Time-series Study site in the Sargasso Sea between 2009 and 2013. Consistent with previous measurements from low-latitude core-top sediments, the annually averaged δ15N of organic matter bound within the shells of euphotic zone-dwelling foraminifera approximates that of thermocline nitrate, the dominant source of new nitrogen to Sargasso Sea surface waters. Based on net tow collections in the upper 200 m of the water column, we observe no systematic difference between the biomass δ15N and shell-bound δ15N of a given foraminifera species. For multiple species, the δ15N of net tow-collected upper ocean shells is lower than shells from sediment traps (by 0.5-2.1‰) and lower than shells from seafloor sediments (by 0.5-1.4‰). We are currently investigating whether these differences reflect actual processes affecting shell-bound δ15N or instead relate to the different time periods over which the three sample types integrate. The foraminiferal biomass δ15N time-series from the surface Sargasso Sea exhibits significant seasonal variations, with the lowest values in fall and the highest values in spring. The roles of hydrography, biogeochemistry, and ecosystem dynamics in driving these seasonal variations will be discussed. These data from the modern subtropical ocean form part of a greater effort to ground-truth the use of foram-bound δ15N to reconstruct past nutrient conditions, not only as a recorder of the isotopic composition of nitrogen supply in oligotrophic environments but also as a recorder of the degree of nitrate consumption in high-latitude regions such as the Southern Ocean.

  10. Benthic foraminifera record and geochemical studies to reconstruct the recent (~400 ya) paleoenvironment of Tomales Bay, California

    Science.gov (United States)

    Flores, S. C.; Hill, T. M.; Russell, A. D.; Brooks, G.

    2010-12-01

    We are conducting investigations of calcareous benthic foraminifera acquired from Tomales Bay, California to reconstruct geochemical conditions of the bay for the past ~400 years, a time period of both natural and anthropogenic environmental change. Tomales Bay, located ~50km northwest of San Francisco, is a long (20.4 km), narrow (0.7 - 1.7 km) and shallow (2.0 - 6.0 m) bay that exhibits long-residence times and is stratified in the summer due to seasonal hypersalinity. Tomales Bay is a unique environment for climate and environmental change research because of the wide documented variability in carbonate parameters (pH, alkalinity, DIC) due to freshwater input from terrestrial sources that decreases aragonite and calcite saturation states. The historical record provided by benthic foraminiferal species and geochemistry, sedimentary carbon (TOC and TIC) analyses, and investigations of recent (Rose-Bengal stained) foraminifera are being utilized to constrain 3 major processes: 1) the range of temperature and salinity shifts over the past 400 years, 2) the relative dominance of marine- vs. fresh-water sources to the bay, and 3) the extent to which freshwater input and runoff may influence water chemistry (saturation state, Ω) with impacts on foraminiferal calcification. Four sediment cores were acquired in 2009 and 2010, and subsequently age-dated utilizing radiocarbon analyses (seven samples). Results indicate an increase in preservation of agglutinated versus calcareous foraminiferal tests (shells) since the mid-1900’s, and greater abundances of agglutinated tests found near freshwater sources. The major calcareous foraminifera present in the record include Elphidium hannai, Elphidium excavatum, Ammonia tepida, and Buccella frigida. Results from oxygen and carbon stable isotope analyses as well as total organic carbon (by weight) for all the cores will also be presented. These results will be compared to modern observations and instrumental records of

  11. Benthic foraminifera or Ostracoda? Comparing the accuracy of palaeoenvironmental indicators from a Pleistocene lagoon of the Romagna coastal plain (Italy)

    Science.gov (United States)

    Barbieri, Giulia; Vaiani, Stefano Claudio

    2018-01-01

    Integrated analyses of multiple groups of microfossils are frequently performed to unravel the palaeoenvironmental evolution of subsurface coastal successions, where the complex interaction among several palaeoecological factors can be detected with benthic assemblages. This work investigates the palaeoenvironmental resolution potential provided by benthic foraminifera and ostracoda within a Pleistocene lagoonal succession of the Romagna coastal plain (northern Italy). Quantitative approaches and statistical techniques have been applied to both groups in order to understand the main factors that controlled the composition of assemblages and compare the palaeoecological record provided by single fossil groups. The two faunal groups are characterized by the high dominance of opportunistic species (Ammonia tepida-Ammonia parkinsoniana and Cyprideis torosa); however, detailed palaeoecological information is inferred from less common taxa. Benthic foraminiferal assemblages are mainly determined by the frequencies of abnormal individuals and species related to high concentrations of organic matter, showing two assemblages: a stressed assemblage, consistent with a brackish-water environment subject to salinity and oxygen fluctuations, and an unstressed assemblage, which indicates more stable conditions. Despite the lower number of species, ostracoda show more significant differences in terms of species composition and ecological structure between their three assemblages, formed in response to a salinity gradient and indicative of inner, central, and outer lagoon conditions. The stratigraphic distribution of ostracod assemblages shows a general transgressive-regressive trend with minor fluctuations, whereas benthic foraminifera highlight the presence of a significant palaeoenvironmental stress. In this case, the higher abundance along the stratigraphic succession, the higher differentiation of the assemblages, and the well-defined relationship between taxa and ecological

  12. Benthic foraminifera (Protista) as indicators of metal pollution in areas of historic mining: examples from southwest England

    Science.gov (United States)

    Hart, Malcolm; Smart, Christopher

    2016-04-01

    Southwest England has been, from Roman times, an important mining area supplying a range of important metals, including copper, tin, tungsten, arsenic, zinc, silver, etc. This mining activity virtually disappeared in the twentieth century, although one tungsten mine near Plymouth has recently re-opened. Large areas of Cornwall and West Devon are now inscribed as the 'Cornish Mining World Heritage Site' on the cultural list of UNESCO. Many of the old mines with their spoil heaps and tailings dams are now protected and, together with the mineral-rich local geology, provide many catchments with on-going metal pollution. In January 1992, after a period of prolonged, heavy rainfall Wheal Jane mine flooded and discharged heavily polluted, acidic, water into Restonguet Creek and the Fal Estuary. This event provided the setting for a detailed investigation of the immediate impact of the pollution and the resulting environmental improvements caused by engineering interventions and natural re-adjustment. Benthic foraminifera disappeared from Restronguet Creek for a number of years and while there is now an abundant, though low diversity, estuarine assemblage of foraminifera living in the creek there are still high levels (pollution can be used to compare with the test deformity data. In other estuarine systems in southwest England, such as the River Fowey and the River Tamar, levels of deformity are less, though still significant for areas no longer being actively mined. This demonstrates that polluted sediments in all these estuaries, which can be disturbed during floods or times of stormy weather, and the background levels of metal elements in the catchments that supply these estuaries, are sufficient to maintain these levels of deformity in the long term. OLUGBODE, O.I., HART, M.B. & STUBBLES, S.J. 2005. Foraminifera from Restronguet Creek: monitoring recovery from the Wheal Jane pollution incident. Geoscience in south-west England, 11, 82-92.

  13. Benthic foraminifera distribution in high polluted sediments from Niterói Harbor (Guanabara Bay, Rio de Janeiro, Brazil

    Directory of Open Access Journals (Sweden)

    Claudia G. Vilela

    2004-03-01

    Full Text Available Dockyards and harbors are recognized as being important locations where sediment-associated pollutants can accumulate, which constitutes an environmental risk to aquatic life due to potential uptake and accumulation of heavy metals in the biota. The aim of this paper is to assess the concentrations and the effects of some heavy metals in the benthic foraminifera assemblage in Niterói Harbor. Low concentrations in the benthic foraminifera as well as the dominance of indicative species such as Ammonia tepida, Buliminella elegantissima and Bolivina lowmani can be associated with an environment under stress. In addition, the occurrence of test abnormalities among foraminifera may represent a useful biomarker for evaluating long-term environmental impacts in a coastal region.Estaleiros e portos são locais reconhecidamente importantes onde poluentes associados a sedimentos podem acumular, constituindo um risco ambiental para a vida aquática devido ao potencial de captação e acumulação de metais pesados na biota. O propósito deste trabalho é avaliar as concentrações e os efeitos de alguns metais pesados na assembléia de foraminíferos bentônicos no Porto de Niterói. Baixas concentrações de foraminíferos bentônicos bem como a dominância de espécies indicativas como Ammonia tepida, Buliminella elegantissima e Bolivina lowmani podem ser associadas a um ambiente sob estresse. A ocorrência de anormalidades entre os foraminíferos pode representar um útil biomarcador para avaliação de impactos ambientais de longo termo em uma região costeira.

  14. Response of benthic foraminifera to 4.2 ka cooling event in the Nakdong River delta, southeast Korea

    Science.gov (United States)

    Takata, H.; Khim, B. K.; Cheong, D.; Shin, S.

    2016-02-01

    Here we report the change of benthic foraminifera in response to 4.2 ka cooling event in the Nakdong River delta (southeastern Korea). It has been known that this cooling event caused climatic deteriorations in the world, which is closely related to the decline/development of the civilizations (e.g., Kawahata et al., 2009). This event was also correlated to one of Bond Events in the North Atlantic. Because coastal sediment depositions have been influenced by both oceanographic and terrestrial climatic changes, the study may provide us clue to understand the possible teleconnection of the cooling event between the North Atlantic and the East Asian margin. We investigated fossil benthic foraminiferal faunas and planktonic/total foraminiferal ratio (P/T ratio) at two borehole cores, ND-01 and ND-02 (landward and seaward sites, respectively). Common constituents are taxa from bay to shelf environments in the East Asian margin. Biotic response of benthic foraminifera partly changed after 4.2 ka showing that Haynesina sp. A (opportunistic species?) decreased significantly at core ND-01. In addition, P/T ratio at both core sites showed temporal decline at 4.2 ka. This suggests the decreasing influence of the seawater relative to the coastal water. Holocene fluctuations of the Tsushima Warm Current, a branch of Kuroshio, flowing off the Nakdong River delta, have been documented. The decline pattern of P/T ratio in this area is similar to that of total sulfur content in Lake Tougou-ike, southwestern Japan at 4 ka which was interpreted as the influence of the small sea-level falling (Kato et al., 2003). According to the similar stratigraphic variation patterns between our and their studies, our finding suggests that this event was not regional but related to the fluctuations of the Tsushima Warm Current. Thus, biotic response of benthic foraminifera in the Nakdong River delta recorded 4.2 ka cooling event related to temporal weakening of the Tsushima Warm Current.

  15. Bearing construction for refrigeration compresssor

    Science.gov (United States)

    Middleton, Marc G.; Nelson, Richard T.

    1988-01-01

    A hermetic refrigeration compressor has a cylinder block and a crankshaft rotatable about a vertical axis to reciprocate a piston in a cylinder on the cylinder block. A separate bearing housing is secured to the central portion of the cylinder block and extends vertically along the crankshaft, where it carries a pair of roller bearings to journal the crankshaft. The crankshaft has a radially extending flange which is journaled by a thrust-type roller bearing above the bearing housing to absorb the vertical forces on the crankshaft so that all three of the roller bearings are between the crankshaft and the bearing housing to maintain and control the close tolerances required by such bearings.

  16. Annual and seasonal distribution of intertidal foraminifera and stable carbon isotope geochemistry, Bandon Marsh, Oregon, USA

    Science.gov (United States)

    Milker, Yvonne; Horton, Benjamin; Vane, Christopher; Engelhart, Simon; Nelson, Alan R.; Witter, Robert C.; Khan, Nicole S.; Bridgeland, William

    2014-01-01

    We investigated the influence of inter-annual and seasonal differences on the distribution of live and dead foraminifera, and the inter-annual variability of stable carbon isotopes (d13C), total organic carbon (TOC) values and carbon to nitrogen (C/N) ratios in bulk sediments from intertidal environments of Bandon Marsh (Oregon, USA). Living and dead foraminiferal species from 10 stations were analyzed over two successive years in the summer (dry) and fall (wet) seasons. There were insignificant inter-annual and seasonal variations in the distribution of live and dead species. But there was a noticeable decrease in calcareous assemblages (Haynesina sp.) between live populations and dead assemblages, indicating that most of the calcareous tests were dissolved after burial; the agglutinated assemblages were comparable between constituents. The live populations and dead assemblages were dominated by Miliammina fusca in the tidal flat and low marsh, Jadammina macrescens, Trochammina inflata and M. fusca in the high marsh, and Trochamminita irregularis and Balticammina pseudomacrescens in the highest marsh to upland. Geochemical analyses (d13C, TOC and C/N of bulk sedimentary organic matter) show no significant influence of inter-annual variations but a significant correlation of d13C values (R = 20.820, p , 0.001), TOC values (R = 0.849, p , 0.001) and C/N ratios (R = 0.885, p , 0.001) to elevation with respect to the tidal frame. Our results suggest that foraminiferal assemblages and d13C and TOC values, as well as C/N ratios, in Bandon Marsh are useful in reconstructing paleosea-levels on the North American Pacific coast.

  17. TEST FUSION IN ADULT FORAMINIFERA: A REVIEW WITH NEW OBSERVATIONS OF AN EARLY EOCENE NUMMULITES SPECIMEN

    Science.gov (United States)

    Ferràndez-Cañadell, Carles; Briguglio, Antonino; Hohenegger, Johann; Wöger, Julia

    2015-01-01

    In foraminifera, so-called “double tests” usually arise due to abnormal growth originating mainly from twinning, but may also be caused by irregularities in the early chambers and by regeneration after test injury that modifies the direction of growth. A fourth cause of double tests has only rarely been reported: the fusion of the tests of two adult individuals. We studied an early Eocene Nummulites double test consisting of two adult individuals that fused after an extended period of independent growth. The specimen was studied using computed tomography with micrometric resolution (micro-CT) that allowed bi- and three-dimensional visualization of the internal structure. Before fusion each individual test had 30–36 chambers, which, by comparison with growth rates in recent nummulitids, implies at least three months of independent growth. After fusion, the compound test grew in two spirals that fused after about one whorl and then continued in a single spiral. To fuse their tests, either adult individuals have to be forced to do so or the allorecognition (ability to distinguish between self and another individual) mechanisms must fail. A possible explanation for the merged Nummulites tests in this study is forced fusion in attached individuals after surviving ingestion and digestion by a metazoan. Alternatively, environmental stress could lead to a failure of allorecognition mechanisms and/or foraminiferal motility. Once fused, subsequent growth seems to be determined mainly by the relative orientation of individual tests. In any case, the frequency in which adult fusion occurs remains unknown. PMID:26166916

  18. Distributions of Benthic Foraminifera in the Salisbury Embayment before and after the PETM Onset

    Science.gov (United States)

    Range, M. M.; Robinson, M. M.

    2017-12-01

    Abrupt climatic perturbations associated with the onset of the Paleocene-Eocene Thermal Maximum (PETM) caused major disruptions to the shallow shelf ecology along the U.S. Atlantic Coastal Plain. Several studies examine the changes in benthic foraminiferal assemblages across the PETM in neritic sediments in New Jersey, Maryland, and Virginia and describe a hydrological and sedimentological paradigm shift that marks the Paleocene-Eocene boundary. In the Salisbury Embayment, a flexural low between the South Jersey High and the Norfolk Arch, this shift is seen in the transition between the upper Paleocene Aquia Formation and the lower Eocene Marlboro Clay. Here we map the abundance of seven benthic foraminifera species from five sites within the Salisbury Embayment from both the uppermost Aquia Formation and the lowermost Marlboro Clay. In addition to the benthic foraminiferal turnover at the PETM onset, we show a geographic distribution of species that highlights a past latitudinal biogeographic zonation not unlike what is found on the modern shelf in this region. Sites document a change in the abundance of species between the late Paleocene and early Eocene, showing a decrease in biodiversity of benthic species along the U.S. Atlantic Coast. Spatial extent of the different species also changed across the Paleocene-Eocene boundary. On the modern Atlantic shelf, a biogeographic zonation is due to the path of the Gulf Stream marking a boundary between relatively cold sea-surface temperatures to the north and warmer temperatures to the south, guided by the geomorphic expression of the mid-Atlantic coastline. During the Paleocene-Eocene transition, we suspect a similar boundary likely existed between the New Jersey sites and the Maryland and Virginia sites. We speculate that with the addition of more assemblage data, we will be able to partially reconstruct the geomorphic expression of the PETM coastline and/or the path of major coastal ocean currents.

  19. Benthic Foraminifera, Food in the Deep Sea, and Limits to Bentho-Pelagic Coupling

    Science.gov (United States)

    Thomas, E.; Boscolo-Galazzo, F.; Arreguin-Rodrigu, G. J.; Ortiz, S.; Alegret, L.

    2015-12-01

    The deep-sea is the largest habitat on Earth, contains highly diverse biota, but is very little known. Many of its abundant benthic biota (e.g., nematodes) are not preserved in the fossil record. Calcareous and agglutinated benthic foraminifera (unicellular eukaryotes, Rhizaria; efficient dispersers) and ostracodes (Animalia, Crustacea; non-efficient dispersers) are the most common organisms providing a fossil record of deep-sea environments. Very little food is supplied to the deep-sea, because organic matter produced by photosynthesis is largely degraded before it arrives at the seafloor. Only a few % of organic matter is carried to the ocean bottom by 'marine snow', with its particle size and behavior in the water column controlled by surface ecosystem structure, including type of dominant primary producers (diatoms, cyanobacteria). Food supply and its seasonality are generally seen as the dominant control on benthic assemblages (combined with oxygenation), providing bentho-pelagic coupling between primary and benthic productivity. Benthic foraminiferal assemblages (composition and density) thus are used widely to estimate past productivity, especially during episodes of global climate change, ocean acidification, and mass extinction of primary producers. We show that some environmental circumstances may result in interrupting bentho-pelagic coupling, e.g. through lateral supply of organic matter along continental margins (adding more refractory organic matter), through trophic focusing and/or fine particle winnowing on seamounts (giving an advantage to suspension feeders), and through carbonate undersaturation (giving advantage to infaunal over epifaunal calcifyers). In addition, increased remineralization of organic matter combined with increased metabolic rates may cause assemblages to reflect more oligotrophic conditions at stable primary productivity during periods of global warming. As a result, benthic foraminiferal accumulation rates must be carefully

  20. 77 FR 70423 - Black Bear Hydro Partners, LLC and Black Bear Development Holdings, LLC and Black Bear SO, LLC...

    Science.gov (United States)

    2012-11-26

    ... Bear Hydro Partners, LLC and Black Bear Development Holdings, LLC and Black Bear SO, LLC; Notice of..., 2012, Black Bear Hydro Partners, LLC, sole licensee (transferor) and Black Bear Development Holdings, LLC and Black Bear SO, LLC (transferees) filed an application for the partial the transfer of licenses...

  1. Introgressive hybridization: brown bears as vectors for polar bear alleles.

    Science.gov (United States)

    Hailer, Frank

    2015-03-01

    The dynamics and consequences of introgression can inform about numerous evolutionary processes. Biologists have therefore long been interested in hybridization. One challenge, however, lies in the identification of nonadmixed genotypes that can serve as a baseline for accurate quantification of admixture. In this issue of Molecular Ecology, Cahill et al. (2015) analyse a genomic data set of 28 polar bears, eight brown bears and one American black bear. Polar bear alleles are found to be introgressed into brown bears not only near a previously identified admixture zone on the Alaskan Admiralty, Baranof and Chichagof (ABC) Islands, but also far into the North American mainland. Elegantly contrasting admixture levels at autosomal and X chromosomal markers, Cahill and colleagues infer that male-biased dispersal has spread these introgressed alleles away from the Late Pleistocene contact zone. Compared to a previous study on the ABC Island population in which an Alaskan brown bear served as a putatively admixture-free reference, Cahill et al. (2015) utilize a newly sequenced Swedish brown bear as admixture baseline. This approach reveals that brown bears have been impacted by introgression from polar bears to a larger extent (up to 8.8% of their genome), than previously known, including the bear that had previously served as admixture baseline. No evidence for introgression of brown bear into polar bear is found, which the authors argue could be a consequence of selection. Besides adding new exciting pieces to the puzzle of polar/brown bear evolutionary history, the study by Cahill and colleagues highlights that wildlife genomics is moving from analysing single genomes towards a landscape genomics approach. © 2015 John Wiley & Sons Ltd.

  2. Taxonomy and distribution of benthic foraminifera from the sediments of Palk Strait, Tamil Nadu, east coast of India

    Digital Repository Service at National Institute of Oceanography (India)

    Gandhi, S.; Rajamanickam, G.V.; Nigam, R.

    .la-b. - Bhalla and Nigam, 1979, p.239. pl. 1.- Nigam and Theide. 1983, pp. 148-149, pl.13, figs.l0a-b. - Mayankar, 1994, p.138, pl.15. - Rao, 1998. p.192. pl.47. figs 5-6. Hypotype : Length - 0.40 mm Breadth - 0.24 mm Remarks : The same species has also been... of western India. Contr. Cush. Found. Forain. Re\\. 7 : 15-24. Bhalia, S.B. and Bhalla, S.N. 1959. Recent foraminifera from the beach sands at Puri, Orissa. Jour. Pal. Soc. India, 4:78-81. Boltovskoy, E. 1954. Foraminiferos de la Bahia San Blas. Rivista del...

  3. Response of shallow water benthic foraminifera to a 13C-labeled food pulse in the laboratory

    Digital Repository Service at National Institute of Oceanography (India)

    Linshy, V.N.; Nigam, R; Heinz, P.

    foraminifera in deep-sea food webs and carbon cycling In: Rowe GT, Pariente V (eds) Deep-Sea food chains and global carbon cycle, Kluwer Academic publishers, The Netherlands, p.63-91 Giullard RR, Ryther JH (1962) Studies of marine planktonic diatoms. I... afterwards to avoid the lysis of cells and stored at −80°C until freeze-drying. The final 13C- concentration in the algae was 75 atom % 13C. 2.3 Experiment Set-up Two time series were incubated for these investigations: one for Ammonia tepida and one...

  4. Multiproxies (benthic foraminifera, ostracods and biopolymers approach applied to identify the environmental partitioning of the Guadiana River Estuary (Iberian Peninsula

    Directory of Open Access Journals (Sweden)

    Lazaro Luiz Mattos Laut

    2016-04-01

    Full Text Available The Guadiana River is the fourth longest river in Europe and is a natural frontier between southern Portugal and Spain. This river was historically used to transport minerals exploited in the region since the Roman Empire and therefore suffered human interventions that have been intensified after the industrial revolution. The Guadiana River has in its limits the Guadiana Valley Natural Park, which is of great value for the Conservation of Geobiodiversity. This study mainly aims to identify zones with the environmental characteristics in the estuarine area of the Guadiana River based on the distribution and ecology of microorganisms (ostracods and foraminifera associated with physicochemical parameters and sedimentological and geochemical (carbohydrate, lipid, protein, total organic carbon and total sulfur data. Fifty-five foraminifera taxa were identified along the estuary with dominance of Ammonia tepida and Miliammina fusca and 13 ostracods taxa with dominance Leptocythere lacertosa and Loxoconcha elliptica. Detrended correspondence analysis (DCA performed using biotic and abiotic variables indicated that pH, grain size, total organic carbon (TOC and lipids were the most influent factors in the distribution of these organisms. Four zones were identified in the Guadiana River estuary: i Low estuary - region with the largest marine influence with sandy sediment, higher salinity and total sulfur and mainly represented by the dominance of estuarine species of foraminifera (Ammonia tepida and Cribroelphidium vadescens and by the ostracods (Darwinula stevensoni, Semicytherura sulcata and Urocythereis oblonga; ii Intermediate estuary - region characterized by neutral pH and sandy sediment enriched in carbohydrates; this region is characterized by the presence of the ostracods species Cytherois fischeri and Neocytherideis subulata and by calcareous and agglutinated species in foraminiferal assemblages; iii Upper estuary - silt, high TOC, proteins and

  5. Methodology for single-cell genetic analysis of planktonic foraminifera for studies of protist diversity and evolution

    Directory of Open Access Journals (Sweden)

    Agnes Katharina Maria Weiner

    2016-12-01

    Full Text Available Single-cell genetic analysis is an essential method to investigate the biodiversity and evolutionary ecology of marine protists. In protist groups that do not reproduce under laboratory conditions, this approach provides the only means to directly associate molecular sequences with cell morphology. The resulting unambiguous taxonomic identification of the DNA sequences is a prerequisite for barcoding and analyses of environmental metagenomic data. Extensive single-cell genetic studies have been carried out on planktonic foraminifera over the past 20 years to elucidate their phylogeny, cryptic diversity, biogeography and the relationship between genetic and morphological variability. In the course of these investigations, it has become evident that genetic analysis at the individual specimen level is confronted by innumerable challenges ranging from the negligible amount of DNA present in the single cell to the substantial amount of DNA contamination introduced by endosymbionts or food particles. Consequently, a range of methods has been developed and applied throughout the years for the genetic analysis of planktonic foraminifera in order to enhance DNA amplification success rates. Yet, the description of these methods in the literature rarely occurred with equivalent levels of detail and the different approaches have never been compared in terms of their efficiency and reproducibility. Here, aiming at a standardization of methods, we provide a comprehensive review of all methods that have been employed for the single-cell genetic analysis of planktonic foraminifera. We compile data on success rates of DNA amplification and use these to evaluate the effects of key parameters associated with the methods of sample collection, storage and extraction of single-cell DNA. We show that the chosen methods influence the success rates of single-cell genetic studies, but the differences between them are not sufficient to hinder comparisons between studies

  6. Application of individual foraminifera Mg/Ca and δ18O analyses for paleoceanographic reconstructions in the Bay of Bengal and other active depositional environments

    Science.gov (United States)

    Fritz-Endres, T.; Dekens, P.; Fehrenbacher, J. S.; Spero, H. J.; Stine, A.

    2017-12-01

    Paleoceanographic research traditionally focuses on regions where sediment deposition is minimally affected by transport. However, sediment fans near tectonically active regions provide an opportunity to link oceanographic climate to terrestrial processes. Sediment cores recovered during IODP Expedition 354 in the Bay of Bengal include hemipelagic sections that record the history of tectonic uplift and the development of the Indian Monsoon through the last 10 Ma. Although these cores provide a unique opportunity to link marine and terrestrial climate, the complex depositional environment requires that the source of foraminifera is carefully considered before using these proxies to reconstruct oceanographic conditions. Foraminifera in Bengal Fan sediments may have been transported via turbidity currents from the northern Bay of Bengal, where the seasonal variability of SST and SSS is larger compared to the southern Bay of Bengal. We measured single Globigerinoides sacculifer Mg/Ca and δ18O from mudline samples of IODP Site U1454 (8.4°N, 85.5°E, 3721 m water depth) near the modern active channel and Site U1449 (8.4°N, 88.7°E, 3653 m water depth) far from channel activity. We compare these sites to single G. sacculifer from the core-top sample of Site 342KL (20.6°N, 90.1°E, 1256 m water depth) located on the continental shelf. Each foraminifera lives 2-4 weeks and the distribution of 60 to 80 data points reflects the seasonal range of SST and SSS at the location where the foraminifera calcified. Measurements in foraminifera from Site U1449 (away from active channel) are statistically different from the site in the northern Bay of Bengal and more consistent with local conditions. Conversely, foraminifera from the site near the active channel reflect a combined signal of local conditions recorded from the site far from channel activity and those recorded from the continental shelf. This suggests a portion of foraminifera from the active channel site have been

  7. A transgressive Santonian-Campanian boundary sequence revisited - High resolution planktonic and benthic foraminifera stratigraphy of the Schattau section, Northern Calcareous Alps.

    Science.gov (United States)

    Wolfgring, Erik; Wagreich, Michael; Summesberger, Herbert; Kroh, Andreas

    2016-04-01

    The Schattau section is part of the Austrian Gosau Group, Northern Calcareous Alps. We record a Santonian to early Campanian transgressive sequence. Previous investigations already provide a biostratigraphic framework; a multidisciplinary study to reveal the local stratigraphy and palaeoenvironmental properties: Planktonic foraminifera, calcareous nannoplankton, ammonite, echinoid and crinoid biostratigraphy data suggest a Santonian to earliest Campanian age for this section (see Wagreich et al., 2009). This work aims at a high resolution assessment of foraminiferal assemblages recorded from a time interval that has undergone significant palaeoenvironmental changes. The Santonian Hochmoos Formation, with the Sandkalkbank Member representing it's topmost subunit, is overlain by the Santonian to Campanian Bibereck Formation. While The Hochmoos Formation records a shallowing succession that finds the Sandkalkbank Member (representing very shallow conditions, sometimes sub aerial exposure) at its top. The overlying Bibereck Formation records a distinct deepening trend displaying increasingly marine, neritic to outer neritic conditions. The stratigraphically older subunits of the Schattau sections are characterised by abundant larger benthic foraminifera (Nummofallotia cretacea), miliolid foraminifera (Quinqueloculina spp, Spiroloculina fassistomata) as well as rotaliid foraminifera (Hoeglundia spp., Gavellina spp.). The Sandkalkbank member marks the end of the shallow water sequence recorded from foraminifera assemblages at the Schattau section. Up section communities are characterised by increasing share of planktonic foraminifera. Biostratigraphic marker fossils like Dicarinella asymetrica and Sigalia sp. (decoratissima?) were identified and indicate a Santonian age for the Bibereck Formation. The appearance of Globotruncanita elevata and disappearance of D. asymetrica and Sigalia sp. Suggests an early Campanian age for the topmost part of the Schattau section

  8. Bathymetric preference of four major genera of rectilinear benthic foraminifera within oxygen minimum zone in Arabian Sea off central west coast of India.

    Digital Repository Service at National Institute of Oceanography (India)

    Mazumder, A.; Nigam, R.

    species, including two species of Bolivina and a single species of Uvigerina, with the bathymetrical variation from the northern Gulf of Mexico. But there is no attempt to correlate the total population of any important genus of rectilinear foraminifera...–900. Malakoff D 1998 Death by suffocation in the Gulf of Mexico; Science 281 190–192. Mallon J, Glock N and Scho¨nfeld J 2012 The response of benthic foraminifera to low-oxygen conditions of the Peruvian oxygen minimum zone; In: ANOXIA: Evidence for eukaryote...

  9. Self lubricating fluid bearings

    International Nuclear Information System (INIS)

    Kapich, D.D.

    1980-01-01

    The invention concerns self lubricating fluid bearings, which are used in a shaft sealed system extending two regions. These regions contain fluids, which have to be isolated. A first seal is fluid tight for the first region between the carter shaft and the shaft. The second seal is fluid tight between the carter and the shaft, it communicates with the second region. The first fluid region is the environment surrounding the shaft carter. The second fluid region is a part of a nuclear reactor which contains the cooling fluid. The shaft is conceived to drive a reactor circulating and cooling fluid [fr

  10. Nanoprecipitation in bearing steels

    International Nuclear Information System (INIS)

    Barrow, A.T.W.; Rivera-Diaz-del-Castillo, P.E.J.

    2011-01-01

    θ-phase is the main hardening species in bearing steels and appears in both martensitically and bainitically hardened microstructures. This work presents a survey of the microstrucural features accompanying nanoprecipitation in bearing steels. Nanoprecipitate structures formed in 1C-1.5Cr wt.% with additions of Cr, Mn, Mo, Si and Ni are studied. The work is combined with thermodynamic calculations and neural networks to predict the expected matrix composition, and whether this will transform martensitically or bainitically. Martensite tetragonality, composition and the amount of retained austenite are related to hardness and the type of nanoprecipitate structures in martensitic grades. The θ-phase volume fraction, the duration of the bainite to austenite transformation and the amount of retained austenite are related to hardness and a detailed quantitative description of the precipitate nanostructures. Such description includes compositional studies using energy-dispersive spectroscopy, which shows that nanoprecipitate formation takes place under paraequilibrium. Special attention is devoted to a novel two-step bainite tempering process which shows maximum hardness; we prove that this is the most effective process for incorporating solute into the precipitates, which are finer than those resulting from one-step banitic transformation processes.

  11. Superconducting bearings in flywheels

    Energy Technology Data Exchange (ETDEWEB)

    Coombs, T.A.; Campbell, A.M.; Ganney, I.; Lo, W. [Cambridge Univ. (United Kingdom). Interdisciplinary Research Centre in Superconductivity (IRC); Twardowski, T. [International Energy Systems, Chester High Road, Neston, South Wirral (United Kingdom); Dawson, B. [British Nuclear Fuels, Capenhurst, South Wirral (United Kingdom)

    1998-05-01

    Investigations are being carried out into the use of superconducting magnetic bearings to levitate energy storage flywheels. In a planned program of work, Cambridge University are aiming to produce a practical bearing system for Pirouette(TM). The Pirouette(TM) system is designed to provide 5 kWh of recoverable energy which is currently recoverable at a rate of 5 kW (future revisions will provide up to 50 kW). IES (a British Nuclear Fuels subsidiary) the owners of the Pirouette(TM) machine have supplied Cambridge with a flywheel. This flywheel weighs >40 kg and is being levitated using an Evershed-type arrangement in which the superconductor is being used to stabilize the interaction between two magnets. To date we have demonstrated stable levitation in static and low speed tests in a rig designed for low speeds of rotation in air. A second rig which is currently under construction at BNFL will run in vacuum at speeds of up to 50 (orig.) 5 refs.

  12. Computational design of rolling bearings

    CERN Document Server

    Nguyen-Schäfer, Hung

    2016-01-01

    This book comprehensively presents the computational design of rolling bearings dealing with many interdisciplinary difficult working fields. They encompass elastohydrodynamics (EHD), Hertzian contact theory, oil-film thickness in elastohydrodynamic lubrication (EHL), bearing dynamics, tribology of surface textures, fatigue failure mechanisms, fatigue lifetimes of rolling bearings and lubricating greases, Weibull distribution, rotor balancing, and airborne noises (NVH) in the rolling bearings. Furthermore, the readers are provided with hands-on essential formulas based on the up-to-date DIN ISO norms and helpful examples for computational design of rolling bearings. The topics are intended for undergraduate and graduate students in mechanical and material engineering, research scientists, and practicing engineers who want to understand the interactions between these working fields and to know how to design the rolling bearings for automotive industry and many other industries.

  13. Benthic foraminifera and heavy metals distribution: A case study from the Naples Harbour (Tyrrhenian Sea, Southern Italy)

    International Nuclear Information System (INIS)

    Ferraro, L.; Sprovieri, M.; Alberico, I.; Lirer, F.; Prevedello, L.; Marsella, E.

    2006-01-01

    The analysis of 90 surficial sediments from three docks of the Naples Harbour (Levante, Granili, and Diaz) permits to compare the distribution modes of heavy metals with grain sizes, total organic carbon content (TOC) and distribution patterns of benthic foraminifera. Foraminiferal density and species richness decrease with the increasing toxic elements concentrations from the Levante to the Diaz dock. Median concentrations of Ni, Pb, Zn, and Hg (medians of 21.43 mg/kg, 270.24 mg/kg, 489.65 mg/kg, and 1.18 mg/kg, respectively) were reported for the Diaz dock where foraminifera are absent, thus suggesting a possible impact of toxic elements on the benthic ecosystem balance. Compared to the unpolluted marine sediments of the Granili dock, the Levante area shows higher heavy metals levels and a quasi-oligotypic benthic assemblage. This is dominated by the tolerant species Ammonia tepida that may be used as bio-indicator of pollution of anthropised marine sediments. - Benthic foraminiferal density and species distribution may be used as pollution indicators

  14. Decalcification and survival of benthic foraminifera under the combined impacts of varying pH and salinity.

    Science.gov (United States)

    Charrieau, Laurie M; Filipsson, Helena L; Nagai, Yukiko; Kawada, Sachiko; Ljung, Karl; Kritzberg, Emma; Toyofuku, Takashi

    2018-04-03

    Coastal areas display natural large environmental variability such as frequent changes in salinity, pH, and carbonate chemistry. Anthropogenic impacts - especially ocean acidification - increase this variability, which may affect the living conditions of coastal species, particularly, calcifiers. We performed culture experiments on living benthic foraminifera to study the combined effects of lowered pH and salinity on the calcification abilities and survival of the coastal, calcitic species Ammonia sp. and Elphidium crispum. We found that in open ocean conditions (salinity ∼35) and lower pH than usual values for these species, the specimens displayed resistance to shell (test) dissolution for a longer time than in brackish conditions (salinity ∼5 to 20). However, the response was species specific as Ammonia sp. specimens survived longer than E. crispum specimens when placed in the same conditions of salinity and pH. Living, decalcified juveniles of Ammonia sp. were observed and we show that desalination is one cause for the decalcification. Finally, we highlight the ability of foraminifera to survive under Ω calc  salinity and [Ca 2+ ] as building blocks are crucial for the foraminiferal calcification process. Copyright © 2018 Elsevier Ltd. All rights reserved.

  15. Distribution of foraminifera in Chincoteague Bay and the marshes of Assateague Island and the adjacent vicinity, Maryland and Virginia

    Science.gov (United States)

    Ellis, Alisha M.; Shaw, Jaimie; Osterman, Lisa E.; Smith, Christopher G.

    2017-11-28

    Scientists from the U.S. Geological Survey (USGS), St. Petersburg Coastal and Marine Science Center conducted a seasonal collection of estuarine, marsh, and sandy washover surface sediments from Chincoteague Bay, Tom’s Cove, and the surrounding Assateague Island and Delmarva Peninsula in March–April and October 2014, after Hurricane Sandy. Micropaleontology samples were collected as part of a complementary USGS Coastal and Marine Geology Program Sea-level and Storm Impacts on Estuarine Environments and Shorelines project study. For comparison with estuarine and overwash deposited foraminifera, a group of scientists from the USGS Woods Hole Coastal and Marine Science Center in Massachusetts collected samples offshore of Assateague Island on the inner continental shelf during a seafloor mapping study in the summer of 2014 and shipped select samples to the St. Petersburg Coastal and Marine Science Center. The micropaleontological subsamples analyzed for foraminifera at each site can be used to establish a foraminiferal baseline assemblage that takes into consideration the seasonal variability of the various species, regarding density and geographic extent, which are influenced by transient and stable environmental parameters. By understanding what parameters affect the various foraminiferal assemblages, researchers can delineate how alterations in salinity, temperature, or marsh-to-bay interactions, such as marsh erosion, might affect that assemblage.

  16. Low palaeoelevation of the northern Lhasa terrane during late Eocene: Fossil foraminifera and stable isotope evidence from the Gerze Basin.

    Science.gov (United States)

    Wei, Yi; Zhang, Kexin; Garzione, Carmala N; Xu, Yadong; Song, Bowen; Ji, Junliang

    2016-06-08

    The Lhasa terrane is a key region for understanding the paleoelevation of the southern Tibetan Plateau after India-Asia collision. The Gerze Basin, located in the northern part of the Lhasa terrane, is a shortening-related basin. We discovered Lagena laevis (Bandy) fossils in upper Eocene strata of the Gerze Basin. This type of foraminifera is associated with lagoon and estuarine environments, indicating that the northern part of the Lhasa terrane was near sea level during the late Eocene. We speculate that these foraminifera were transported inland by storm surges to low elevation freshwater lakes during times of marine transgressions. This inference is consistent with the relatively positive δ(18)O values in carbonate from the same deposits that indicate low palaeoelevations close to sea level. Considering the palaeoelevation results from the nearby Oligocene basins at a similar latitude and the volcanic history of the Lhasa terrane, we infer that large-magnitude surface uplift of the northern Lhasa terrane occurred between late Eocene and late Oligocene time.

  17. Grease lubrication in rolling bearings

    CERN Document Server

    Lugt, Piet M

    2012-01-01

    The definitive book on the science of grease lubrication for roller and needle bearings in industrial and vehicle engineering. Grease Lubrication in Rolling Bearings provides an overview of the existing knowledge on the various aspects of grease lubrication (including lubrication systems) and the state of the art models that exist today. The book reviews the physical and chemical aspects of grease lubrication, primarily directed towards lubrication of rolling bearings. The first part of the book covers grease composition, properties and rheology, including thermal

  18. Hydrostatic and hybrid bearing design

    CERN Document Server

    Rowe, W B

    1983-01-01

    Hydrostatic and Hybrid Bearing Design is a 15-chapter book that focuses on the bearing design and testing. This book first describes the application of hydrostatic bearings, as well as the device pressure, flow, force, power, and temperature. Subsequent chapters discuss the load and flow rate of thrust pads; circuit design, flow control, load, and stiffness; and the basis of the design procedures and selection of tolerances. The specific types of bearings, their design, dynamics, and experimental methods and testing are also shown. This book will be very valuable to students of engineering des

  19. Quantifying the effect of seasonal and vertical habitat tracking on planktonic foraminifera proxies

    Directory of Open Access Journals (Sweden)

    L. Jonkers

    2017-06-01

    Full Text Available The composition of planktonic foraminiferal (PF calcite is routinely used to reconstruct climate variability. However, PF ecology leaves a large imprint on the proxy signal: seasonal and vertical habitats of PF species vary spatially, causing variable offsets from annual mean surface conditions recorded by sedimentary assemblages. PF seasonality changes with temperature in a way that minimises the environmental change that individual species experience and it is not unlikely that changes in depth habitat also result from such habitat tracking. While this behaviour could lead to an underestimation of spatial or temporal trends as well as of variability in proxy records, most palaeoceanographic studies are (implicitly based on the assumption of a constant habitat. Up to now, the effect of habitat tracking on foraminifera proxy records has not yet been formally quantified on a global scale. Here we attempt to characterise this effect on the amplitude of environmental change recorded in sedimentary PF using core top δ18O data from six species. We find that the offset from mean annual near-surface δ18O values varies with temperature, with PF δ18O indicating warmer than mean conditions in colder waters (on average by −0.1 ‰ (equivalent to 0.4 °C per °C, thus providing a first-order quantification of the degree of underestimation due to habitat tracking. We use an empirical model to estimate the contribution of seasonality to the observed difference between PF and annual mean δ18O and use the residual Δδ18O to assess trends in calcification depth. Our analysis indicates that given an observation-based model parametrisation calcification depth increases with temperature in all species and sensitivity analysis suggests that a temperature-related seasonal habitat adjustment is essential to explain the observed isotope signal. Habitat tracking can thus lead to a significant reduction in the amplitude of recorded environmental change

  20. Benthic foraminifera response to Holocene environmental changes in the ria de Muros (NW Spain)

    Science.gov (United States)

    Diz, P.; Francés, G.; Pena, L. D.; Nombela, M. A.; Alejo, I.

    2003-04-01

    Benthic foraminifera assemblages from the outer sector of the ría de Muros have been analyzed in order to obtain a detailed reconstruction of Holocene environmental evolution. The studied core (EUGC-3B: 42' 45.10'N; 9' 02.23'W, at 38 m.b.s.l. and 410 cm length) consists of muddy sand from the core bottom (8200 cal yr BP) to 200 cm (2700 cal yr BP) and mainly mud from 200 cm to the core top. Measurements of geochemical properties carried out by a XRF core scanner revealed different signatures in the two aforementioned intervals and an enhancing terrigenous influence during the last 2000 yr. The prevalence of Bulimina spp., Nonion fabum, Ammonia beccarii and Cibicides ungerianus along the whole core indicates high organic carbon concentration and/or low oxygenation levels into the sediment. Nevertheless, the percentage of these species shows noticeable changes, indicating the existence of five periods with different environmental conditions. The basal assemblage (8200-7500 cal yr BP) is dominated by epifaunal taxa and it can be interpreted as a low sea level assemblage. An increase of fresh water influence during the Holocene Climate Optimum (7500-5000 cal yr BP) is revealed by maxima percentages of A. beccarii. The oceanic influence increased during the Subboreal period (5000-2750 cal yr BP) leading to an active water interchange between the ría and the open ocean and a higher marine productivity. The oceanic influence is recorded by the increase of typical marine species as Elphidium advenum, Bulimina spp., N. fabum, and Nonionella turgida. The appearance of Rectuvigerina phlegeri at 4000 cal yr BP denotes full marine conditions. Environmental conditions similar to the current ones were achieved during the Subatlantic period (2750-Rec). In a first step an assemblage dominated by Bulimina spp. N. fabum, and C. ungerianus permit us to interpret a relatively stable period with episodic pulses of fluvial influence. Afterwards the appearance and the rapid increase of

  1. Glacial-interglacial changes in the surface water characteristics of the Andaman Sea: Evidence from stable isotopic ratios of planktonic foraminifera

    Digital Repository Service at National Institute of Oceanography (India)

    Ahmad, S.M.; Patil, D.J.; Rao, P.S.; Nath, B.N.; Rao, B.R.; Rajagopalan, G.

    ; Nature 343 549--551 Shackleton N J 1974 Attainment of isotopic equilibrium between ocean water and benthonic foraminifera genus Uvigerina: Isotopic changes in the ocean during the last glacial; In: Les Methodes quantitatives d'etude des variation du... climat au cours du pleistocene. Coll. Int. CNRS Paris 119 203--210 156 S M Ahmad et al ...

  2. Benthic foraminifera as biostratigraphical and paleoecological indicators: An example from Oligo-Miocene deposits in the SW of Zagros basin, Iran

    Directory of Open Access Journals (Sweden)

    Asghar Roozpeykar

    2016-01-01

    Full Text Available The Asmari Formation is a predominantly carbonate lithostratigraphic unit that outcrops in the Zagros Basin. Micropaleontological studies of the Asmari Formation in the Dehdasht area led to the identification of 51 species of foraminifera taxa. Among the foraminifera, Nummulites cf. vascus, Operculin sp., Operculina complanata, Eulepidina dilatata, Eulepidina elephantine, Ditrupa sp., Miogypsina sp., Elphidium sp. 14, and Borelis melo curdica are the most important. The Lepidocyclina-Operculina-Ditrupa assemblage zone represents the Rupelian–Chattian age. The Aquitanian age is also defined by co-occurrence of Miogypsina sp. and Elphidium sp. 14, and finally, the first occurrence of Borelis melo curdica represents the Burdigalian. Based on faunal assemblages, the following paleoenvironmental settings are determined for the deposition of the study section: (1 the deep, offshore settings in the aphotic zone dominated by pelagic and small benthic foraminifera; (2 the low energy, turbid and low light parts of the oligophotic zone characterized by large and flat lepidocyclinids (Eulepidina and Nummulitidae; (3 the low turbidity, deeper part of the inner ramp dominated by Miogypsinoides, Neorotalia, Lepidocyclina, Operculina and Archias; (4 the shallow, marginal marine environment exposed to salinity fluctuations (short-term salinity fluctuations or fully marine conditions dominated by small benthic Foraminifera (Ammonia and Elphidium; (5 highly translucent, shallowest part of the inner ramp dominated by representatives of Borelis, Meandropsina and Peneroplis. The biotic assemblages represent warm tropical waters with oligotrophic to slightly mesotrophic conditions.

  3. The evaluation of Computed Tomography hard- and software tools for micropaleontologic studies on foraminifera

    Science.gov (United States)

    van Loo, D.; Speijer, R.; Masschaele, B.; Dierick, M.; Cnudde, V.; Boone, M.; de Witte, Y.; Dewanckele, J.; van Hoorebeke, L.; Jacobs, P.

    2009-04-01

    Foraminifera (Forams) are single-celled amoeba-like organisms in the sea, which build a tiny calcareous multi-chambered shell for protection. Their enormous abundance, great variation of shape through time and their presence in all marine deposits made these tiny microfossils the oil companies' best friend by facilitating the detection of new oil wells. Besides the success of forams in the oil and gas industry, they are also a most powerful tool for reconstructing climate change in the past. The shell of a foraminifer is a tiny gold mine of information both geometrical as chemical. However, until recently the best information on this architecture was only obtained through imaging the outside of a shell with Scanning Electron Microscopy (SEM), giving no clues towards internal structures other than single snapshots through breaking a specimen apart. With X-ray computed tomography (CT) it is possible to overcome this problem and uncover a huge amount of geometrical information without destructing the samples. Using the last generation of micro-CT's, called nano-CT, because of the sub-micron resolution, it is now possible to perform adequate imaging even on these tiny samples without needing huge facilities. In this research, a comparison is made between different X-ray sources and X-ray detectors and the resulting image resolution. Both sharpness, noise and contrast are very important parameters that will have important effects on the accuracy of the results and on the speed of data-processing. Combining this tomography technique with specific image processing software, called segmentation, it is possible to obtain a 3D virtual representation of the entire forams shell. This 3D virtual object can then be used for many purposes, from which automatic measurement of the chambers size is one of the most important ones. The segmentation process is a combination of several algorithms that are often used in CT evaluation, in this work an evaluation of those algorithms is

  4. Superconducting bearings for flywheel applications

    Energy Technology Data Exchange (ETDEWEB)

    Abrahamsen, Asger Bech

    2001-05-01

    A literature study on the application of superconducting bearings in energy storage flywheel systems. The physics of magnetic levitation and superconductors are presented in the first part of the report, followed by a discussion of the literature found on the applications of superconducting bearings in flywheels. (au)

  5. Superconducting bearings for flywheel applications

    DEFF Research Database (Denmark)

    Abrahamsen, A.B.

    2001-01-01

    A literature study on the application of superconducting bearings in energy storage flywheel systems. The physics of magnetic levitation and superconductors are presented in the first part of the report, followed by a discussion of the literature found onthe applications of superconducting bearings...

  6. Carbon and nitrogen uptake of calcareous benthic foraminifera along a depth-related oxygen gradient in the OMZ of the Arabian Sea

    Directory of Open Access Journals (Sweden)

    Annekatrin Julie Enge

    2016-02-01

    Full Text Available Foraminifera are an important faunal element of the benthos in oxygen-depleted settings such as Oxygen Minimum Zones (OMZs where they can play a relevant role in the processing of phytodetritus. We investigated the uptake of phytodetritus (labeled with 13C and 15N by cal-careous foraminifera in the 0-1 cm sediment horizon under different oxygen concentrations within the OMZ in the eastern Arabian Sea. The in situ tracer experiments were carried out along a depth transect on the Indian margin over a period of 4 to 10 days. The uptake of phy-todetrital carbon within 4 days by all investigated species shows that phytodetritus is a rele-vant food source for foraminifera in OMZ sediments. The decrease of total carbon uptake from 540 to 1100 m suggests a higher demand for carbon by species in the low-oxygen core region of the OMZ or less food competition with macrofauna. Especially Uvigerinids showed high uptake of phytodetrital carbon at the lowest oxygenated site. Variation in the ratio of phytodetrital carbon to nitrogen between species and sites indicates that foraminiferal carbon and nitrogen use can be decoupled and different nutritional demands are found between spe-cies. Lower ratio of phytodetrital carbon and nitrogen at 540 m could hint for greater demand or storage of food-based nitrogen, ingestion or hosting of bacteria under almost anoxic condi-tions. Shifts in the foraminiferal assemblage structure (controlled by oxygen or food availabil-ity and in the presence of other benthic organisms account for observed changes in the pro-cessing of phytodetritus in the different OMZ habitats. Foraminifera dominate the short-term processing of phytodetritus in the OMZ core but are less important in the lower OMZ bounda-ry region of the Indian margin as biological interactions and species distribution of foraminif-era change with depth and oxygen levels.

  7. Space Station alpha joint bearing

    Science.gov (United States)

    Everman, Michael R.; Jones, P. Alan; Spencer, Porter A.

    1987-01-01

    Perhaps the most critical structural system aboard the Space Station is the Solar Alpha Rotary Joint which helps align the power generation system with the sun. The joint must provide structural support and controlled rotation to the outboard transverse booms as well as power and data transfer across the joint. The Solar Alpha Rotary Joint is composed of two transition sections and an integral, large diameter bearing. Alpha joint bearing design presents a particularly interesting problem because of its large size and need for high reliability, stiffness, and on orbit maintability. The discrete roller bearing developed is a novel refinement to cam follower technology. It offers thermal compensation and ease of on-orbit maintenance that are not found in conventional rolling element bearings. How the bearing design evolved is summarized. Driving requirements are reviewed, alternative concepts assessed, and the selected design is described.

  8. Flywheel Challenge: HTS Magnetic Bearing

    International Nuclear Information System (INIS)

    Werfel, F N; Floegel-Delor, U; Riedel, T; Rothfeld, R; Wippich, D; Goebel, B

    2006-01-01

    A 200 mm cylindrical engineering prototype high temperature superconducting (HTS) was designed and fabricated. Measurements show that the 17 kg PM rotor can suspend safely 1000 kg in axial direction and 470 kg radially. The rationale for the bearing performance is to stabilize a 400 kg rotor of a new compact 5 kWh/280 kW flywheel energy storage system (COM - FESS). Measurements of the magnetic bearing force, stiffness and drag-torque are presented indicated the successful targeting a milestone in the HTS bearing technology. The influence of the PM configuration and the YBCO temperature on the bearing performance was experimentally studied, providing high-force or high-stiffness behaviour. The axial stiffness 5 kN/mm at 0.5 mm displacement is the highest value of a HTS bearing we know

  9. Journal bearing impedance descriptions for rotordynamic applications

    NARCIS (Netherlands)

    Childs, D.W.; Moes, H.; Leeuwen, van H.J.

    1977-01-01

    Bearing impedance vectors are introduced for plain journal bearings which define the bearing reaction force components as a function of the bearing motion. Impedance descriptions are developed directly for the approximate Ocvirk (short) and Sommerfeld (long) bearing solutions. The impedance vector

  10. Benthic foraminifera cultured over a large salinity gradient: first results and comparison with field data from the Baltic Sea.

    Science.gov (United States)

    Groeneveld, Jeroen; Filipsson, Helena L.; Austin, William E. N.; Darling, Kate; Quintana Krupinski, Nadine B.

    2015-04-01

    Some of the most significant challenges in paleoclimate research arise from the need to both understand and reduce the uncertainty associated with proxy methods for climate reconstructions. This is especially important for shelf and coastal environments where increasing numbers of high-resolution paleorecords are being generated. These challenges are further highlighted in connection with ECORD/IODP Expedition 347: Baltic Sea Paleoenvironments. This large-scale drilling operation took place in the Baltic Sea region during the autumn of 2013. At this time, there is a pressing need for proxy calibrations directly targeted at the brackish Baltic environment. Within the CONTEMPORARY project we are investigating different temperature and salinity proxy variables through a combination of field- and culture-based benthic foraminiferal samples, together with genetic characterization (genotyping) of the morphospecies. We have completed two field campaigns where we collected (living) foraminifera and water samples at several sites, ranging from fully marine to low salinity conditions. The core-top foraminifera have been analysed for trace metal/Ca, stable oxygen and carbon isotopes, and faunal composition. Living foraminifera collected from the sediment-water interface were cultured in sea water in two long-term experiments at different temperatures (5°C and 10°C) and at three different salinities (15, 25, and 35). The first experiment yielded a large number of reproduced and experimentally-grown Elphidium specimens. The second experiment resulted in growth but no reproduction. We will provide a summary of the experimentally grown material and discuss the challenges of generating new proxy calibrations for foraminiferal shell geochemistry in the Baltic Sea. Furthermore, specimens of Elphidium and Ammonia, found at two sampling sites (Anholt, Kattegat and Hanöbay) with differing salinities, were genotyped and the results indicate that the same genotype of Elphidium is

  11. Foraminifera eco-biostratigraphy of the southern Evoikos outer shelf, central Aegean Sea, during MIS 5 to present

    Science.gov (United States)

    Drinia, Hara; Antonarakou, Assimina; Tsourou, Theodora; Kontakiotis, George; Psychogiou, Maria; Anastasakis, George

    2016-09-01

    The South Evoikos Basin is a marginal basin in the Aegean Sea which receives little terrigenous supply and its sedimentation is dominated by hemipelagic processes. Late Quaternary benthic and planktonic foraminifera from core PAG-155 are investigated in order to understand their response to the glacial-interglacial cycles in this region. The quantitative analysis of planktonic foraminifera, coupled with accelerator mass spectrometry (14C-AMS) radiocarbon date measurements, provide an integrated chrono-stratigraphic time framework over the last 90 ka (time interval between late Marine Isotopic Stages 5 and 1; MIS5-MIS1). The temporary appearance and disappearance as well as several abundance peaks in the quantitative distribution of selected climate-sensitive planktonic species allowed the identification of several eco-bioevents, useful to accurately mark the boundaries of the eco-biozones widely recognized in the Mediterranean records and used for large-scale correlations. The established bio-ecozonation scheme allows a detailed palaecological reconstruction for the late Pleistocene archive in the central Aegean, and furthermore provides a notable contribution for palaeoclimatic studies, facilitating intercorrelations between various oceanographic basins. The quantitative analyses of benthic foraminifera identify four distinct assemblages, namely Biofacies: Elphidium spp., Haynesina spp. Biofacies, characterized by neritic species, dominated during the transition from MIS 5 to MIS 4; Cassidulina laevigata/carinata Biofacies dominated till 42 ka (transgressive trend from MIS 4 to MIS 3); Bulimina gibba Biofacies dominated from 42 ka to 9.5 ka (extensive regression MIS 3,2 through lowstand and early transgression; beginning of MIS 1); Bulimina marginata, Uvigerina spp. Biofacies dominated from 9.5 ka to the present (late transgression through early highstand; MIS 1)., This study showed that the South Evoikos Basin which is characterized by its critical depths and

  12. Recipe Book for Larger Benthic Foraminifera X-ray Investigation: a Process Approach

    Science.gov (United States)

    Wolfgring, E.; Briguglio, A.; Hohenegger, J.

    2012-04-01

    During the past years X-ray microtomography (microCT) has become an essential tool in imaging procedures in micropaleontology. Apart from highest standards in accuracy, well conducted microCT scans aim to resolve the whole specimen in constant quality and free from any artifacts or visual interferences. Normally, to get used to X-ray techniques and get usable results, countless attempts are needed, resulting in enormous waste of time. This work tries to provide an insight into how best exploitable results can be obtained from the scanning process concerning Larger Benthic Foraminifera (LBF). As each specimen features different characteristics regarding substantial composition, density and conservation status, it is impossible and probably erroneous to give standardized guidelines even within this systematic group. Depending on the attributes of the specimen and on the desired visualization, several details have to be taken into account. Samples preparation: to get sharp images the X-ray has to cross the specimen along its shortest diameter, for LBF the equatorial view is almost always the best positioning (not for alveolinids!). The container itself has to be chosen wisely as well; it must not affect a flawless penetration of the specimen by the X-ray and has to provide a high degree of stability. Small plastic pipettes are perfect to store the specimen (or specimens) and some cardboard may help in keeping the position. The nature and quality of the paste used to fixate the object and its container are essential in ensuring a smooth rotation of the specimen which is inevitable for the consistent quality of the image and to avoid vibrations. Scan parameters: beside the correct choice of dedicated filters (which are always different depending on the working station), settings for kv, µA and resolution might have to be revised for each new object to deliver optimal results. Standard values for hyaline forms with empty chambers are normally around 80 Kv and 100 u

  13. Bone Regeneration of Rat Tibial Defect by Zinc-Tricalcium Phosphate (Zn-TCP Synthesized from Porous Foraminifera Carbonate Macrospheres

    Directory of Open Access Journals (Sweden)

    Joshua Chou

    2013-12-01

    Full Text Available Foraminifera carbonate exoskeleton was hydrothermally converted to biocompatible and biodegradable zinc-tricalcium phosphate (Zn-TCP as an alternative biomimetic material for bone fracture repair. Zn-TCP samples implanted in a rat tibial defect model for eight weeks were compared with unfilled defect and beta-tricalcium phosphate showing accelerated bone regeneration compared with the control groups, with statistically significant bone mineral density and bone mineral content growth. CT images of the defect showed restoration of cancellous bone in Zn-TCP and only minimal growth in control group. Histological slices reveal bone in-growth within the pores and porous chamber of the material detailing good bone-material integration with the presence of blood vessels. These results exhibit the future potential of biomimetic Zn-TCP as bone grafts for bone fracture repair.

  14. Ostracoda and foraminifera as short-term tracers of environmental changes in very polluted areas: the Odiel Estuary (SW Spain)

    International Nuclear Information System (INIS)

    Ruiz, F.; Gonzalez-Regalado, M.L.; Borrego, J.; Abad, M.; Pendon, J.G.

    2004-01-01

    The analysis of 17 cores collected in the Odiel Estuary (SW Spain) permits delimiting the recent evolution of this zone during the past decades and the influence of natural and anthropogenic factors on the distribution of Ostracoda and Foraminifera. In the upper estuary, the coincidence of acid waters, prolonged subaerial exposure, and coarse sediments may explain the absence or the disappearance of these microorganisms during the industrial period (1966-1985) in the major part of this area. In the lower estuary, sedimentary evolution and industrial wastes are the main factors influencing both the distribution and trends of the populations of these two groups. Finally, the main changes observed in the marine estuary are due to the sedimentary effects of the construction of two banks and the dredging of the main estuarine channel. - In a polluted estuary, the meiofaunal assemblages experience different changes even in adjacent sedimentary environments, closely related to anthropogenic and natural causes

  15. Biomonitoring polluted sediments in Arctic regions - possibilities and challenges using benthic foraminifera. Case studies from northern Norway

    Science.gov (United States)

    Skirbekk, Kari; Dijkstra, Noortje; Junttila, Juho; Sternal, Beata; Pedersen, Kristine Bondo; Forwick, Matthias; Carroll, JoLynn

    2016-04-01

    Biomonitoring pollution in marine environments using benthic foraminifera assemblages have proven to be a valid method for many regions. Two important reasons for their suitability are their sensitivity to changes in the environment and their rapid response time due to short life cycles. In addition, they are preserved in the sedimentary record, allowing for baseline studies of conditions prior to introduction of contaminants. Species of benthic foraminifera that appear to tolerate polluted sediments are referred to as opportunistic species. This notion is in general used for species able to dominate environments that are too stressful for most species. The high latitude setting of the northern Norwegian coastal zone experience high seasonality and, hence, largely changing conditions throughout a year: variations in water mass domination, freshwater influence, temperature and current velocity. It is possible that an environment like this is inhibited by a higher amount of opportunistic species generally thriving under high stress conditions. This might make the use of benthic foraminifera for biomonitoring more challenging, as the faunal compositions may be a result of a complex set of processes. Consequently, large datasets are necessary in order to make reliable conclusions, which in time may be used as generalized guidelines for biomonitoring in this geographical area. Here, we present preliminary results of benthic foraminiferal assemblages from two sites in Finnmark, northern Norway, which have been exposed to pollution. The main site is Repparfjorden, where the inner parts of the fjord were used as a submarine waste deposal site for mine tailings from a local copper mine during the 1970´s. Results from four marine sediment cores (10-20 cm long) containing sediments classified to be in moderate to very bad state (according to Norwegian sediment quality criteria) are presented. The contamination is seen in intervals of elevated copper content dated to the 1970

  16. Eastern slopes grizzly bear project

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2001-01-01

    The cumulative effects of human activities on the grizzly bears in the central Canadian Rockies are not well known. As a result, a project was initiated in 1994 to address the urgent requirement for accurate scientific information on the habitat and populations of grizzly bears in the area of the Banff National Park and Kananaskis Country. This area is probably the most heavily used and developed area where the grizzly still survives. The information gathered throughout the course of this study will be used to better protect and manage the bears and other sensitive carnivores in the region. Using telemetry, researchers are monitoring 25 grizzly bears which were radio-collared in a 22,000 square-kilometer area in the upper Bow Valley drainage of the eastern Alberta slopes. The researchers involved in the project are working with representatives from Husky Oil and Talisman Energy on the sound development of the Moose Mountain oil and gas field without adversely affecting the grizzly bear population. Information collected over seven years indicated that the grizzly bears have few and infrequent offspring. Using the information gathered so far, the location of the Moose Mountain to Jumping Pound pipeline was carefully selected, since the bears recover very slowly from high mortality, and also considering that the food and cover had already been compromised by the high number of roads, trails and other human activities in the area. The status of the population and habitat of the grizzly bear will be assessed upon the conclusion of the field research phase in 2001. Models will be updated using the data obtained during eight years and will assist in the understanding of complex variables that affect grizzly bears.

  17. EFFECT OF BEARING MACROGEOMETRY ON BEARING PERFORMANCE IN ELASTOHYDRODYNAMIC LUBRICATION

    Directory of Open Access Journals (Sweden)

    Emin GÜLLÜ

    2000-01-01

    Full Text Available During manufacturing, ideal dimension and mutual positioning of machine elements proposed in project desing can be achieved only within certain range of tolerances. These tolerances, being classified in two groups, related to micro and macro geometry of machine elements, don't have to effect the functioning of these elements. So, as for all machine elements, investigation of the effects of macro and micro tolerances for journal bearings is important. In this study, we have investigated the effect of macro geometric irregularities of journal bearings on performance characteristics. In this regard, we have studied the change of bearing performance in respect to deviation from ideal circle for an elliptic shaft with small ovality rolling in circular journal bearing.

  18. Increased temperature causes different carbon and nitrogen processing patterns in two common intertidal foraminifera (Ammonia tepida and Haynesina germanica

    Directory of Open Access Journals (Sweden)

    J. Wukovits

    2017-06-01

    Full Text Available Benthic foraminifera are highly abundant heterotrophic protists in marine sediments, but future environmental changes will challenge the tolerance limits of intertidal species. Metabolic rates and physiological processes in foraminifera are strongly dependent on environmental temperatures. Temperature-related stress could therefore impact foraminiferal food source processing efficiency and might result in altered nutrient fluxes through the intertidal food web. In this study, we performed a laboratory feeding experiment on Ammonia tepida and Haynesina germanica, two dominant foraminiferal species of the German Wadden Sea/Friedrichskoog, to test the effect of temperature on phytodetritus retention. The specimens were fed with 13C and 15N labelled freeze-dried Dunaliella tertiolecta (green algae at the start of the experiment and were incubated at 20, 25 and 30 °C respectively. Dual labelling was applied to observe potential temperature effects on the relation of phytodetrital carbon and nitrogen retention. Samples were taken over a period of 2 weeks. Foraminiferal cytoplasm was isotopically analysed to investigate differences in carbon and nitrogen uptake derived from the food source. Both species showed a positive response to the provided food source, but carbon uptake rates of A. tepida were 10-fold higher compared to those of H. germanica. Increased temperatures had a far stronger impact on the carbon uptake of H. germanica than on A. tepida. A distinct increase in the levels of phytodetrital-derived nitrogen (compared to more steady carbon levels could be observed over the course of the experiment in both species. The results suggest that higher temperatures have a significant negative effect on the carbon exploitation of H. germanica. For A. tepida, higher carbon uptake rates and the enhanced tolerance range for higher temperatures could outline an advantage in warmer periods if the main food source consists of chlorophyte phytodetritus

  19. Increased temperature causes different carbon and nitrogen processing patterns in two common intertidal foraminifera (Ammonia tepida and Haynesina germanica)

    Science.gov (United States)

    Wukovits, Julia; Enge, Annekatrin Julie; Wanek, Wolfgang; Watzka, Margarete; Heinz, Petra

    2017-06-01

    Benthic foraminifera are highly abundant heterotrophic protists in marine sediments, but future environmental changes will challenge the tolerance limits of intertidal species. Metabolic rates and physiological processes in foraminifera are strongly dependent on environmental temperatures. Temperature-related stress could therefore impact foraminiferal food source processing efficiency and might result in altered nutrient fluxes through the intertidal food web. In this study, we performed a laboratory feeding experiment on Ammonia tepida and Haynesina germanica, two dominant foraminiferal species of the German Wadden Sea/Friedrichskoog, to test the effect of temperature on phytodetritus retention. The specimens were fed with 13C and 15N labelled freeze-dried Dunaliella tertiolecta (green algae) at the start of the experiment and were incubated at 20, 25 and 30 °C respectively. Dual labelling was applied to observe potential temperature effects on the relation of phytodetrital carbon and nitrogen retention. Samples were taken over a period of 2 weeks. Foraminiferal cytoplasm was isotopically analysed to investigate differences in carbon and nitrogen uptake derived from the food source. Both species showed a positive response to the provided food source, but carbon uptake rates of A. tepida were 10-fold higher compared to those of H. germanica. Increased temperatures had a far stronger impact on the carbon uptake of H. germanica than on A. tepida. A distinct increase in the levels of phytodetrital-derived nitrogen (compared to more steady carbon levels) could be observed over the course of the experiment in both species. The results suggest that higher temperatures have a significant negative effect on the carbon exploitation of H. germanica. For A. tepida, higher carbon uptake rates and the enhanced tolerance range for higher temperatures could outline an advantage in warmer periods if the main food source consists of chlorophyte phytodetritus. These conditions are

  20. Non-contacting "snubber bearing" for passive magnetic bearing systems

    Science.gov (United States)

    Post, Richard F

    2017-08-22

    A new non-contacting magnetic "snubber" bearing is provided for application to rotating systems such as vehicular electromechanical battery systems subject to frequent accelerations. The design is such that in the equilibrium position the drag force of the snubber is very small (milliwatts). However in a typical case, if the rotor is displaced by as little as 2 millimeters a large restoring force is generated without any physical contact between the stationary and rotating parts of the snubber bearing.

  1. Bears, Big and Little. Young Discovery Library Series.

    Science.gov (United States)

    Pfeffer, Pierre

    This book is written for children 5 through 10. Part of a series designed to develop their curiosity, fascinate them and educate them, this volume describes: (1) the eight species of bears, including black bear, brown bear, grizzly bear, spectacled bear, sun bear, sloth bear, polar bear, and giant panda; (2) geographical habitats of bears; (3)…

  2. LEPINOCONUS CHIOCCHINII GEN. N., N. SP., A CONICAL AGGLUTINATED FORAMINIFERA FROM THE UPPER CRETACEOUS OF ITALY

    Directory of Open Access Journals (Sweden)

    ERZIKA CRUZ-ABAD

    2017-04-01

    Full Text Available A new conical agglutinated foraminifer, Lepinoconus chiocchinii gen n., n. sp. from the lower Campanian shallow-water platform deposits of the Lepini Mountains (central Apennines, Italy, is described. It has a pseudo-keriothecal wall structure, uniserial arrangement of the adult chambers and multiple apertures. The exoskeleton is constituted by beams (main and intercalary continuous from one chamber to the next, while the endoskeleton bears pillars. The new taxon is included in the Coskinolinidae family. Lepinoconus chiocchinii gen. n., n. sp. is known from southern Italy, Greece and Albania.

  3. Water-bearing explosive compositions

    Energy Technology Data Exchange (ETDEWEB)

    Gay, G M

    1970-12-21

    An explosive water-bearing composition, with high detonation velocity, comprises a mixture of (1) an inorganic oxidizer salt; (2) nitroglycerine; (3) nitrocellulose; (4) water; and (5) a water thickening agent. (11 claims)

  4. Failure analysis of superconducting bearings

    Energy Technology Data Exchange (ETDEWEB)

    Rastogi, Amit; Campbell, A M; Coombs, T A [Department of Engineering, University of Cambridge, Cambridge CB2 1PZ (United Kingdom)

    2006-06-01

    The dynamics of superconductor bearings in a cryogenic failure scenario have been analyzed. As the superconductor warms up, the rotor goes through multiple resonance frequencies, begins to slow down and finally touches down when the superconductor goes through its transition temperature. The bearing can be modelled as a system of springs with axial, radial and cross stiffness. These springs go through various resonant modes as the temperature of the superconductor begins to rise. We have presented possible explanations for such behavio0008.

  5. Superconducting composite for magnetic bearings

    International Nuclear Information System (INIS)

    Rigney, T.K. II.

    1995-01-01

    A composite includes granules of Type II superconducting material and granules of rare-earth permanent magnets that are distributed in a binder. The composite is a two-phase structure that combines the properties of the superconductor and magnets with the flexibility and toughness of a polymeric material. A bearing made from this composite has the load capacity and stiffness of a permanent magnet bearing with added stability from a Type II superconducting material. 7 figs

  6. Effects of short-term environmental disturbances on living benthic foraminifera during the Pacific oyster summer mortality in the Marennes-Oléron Bay (France).

    Science.gov (United States)

    Bouchet, Vincent M P; Debenay, Jean-Pierre; Sauriau, Pierre-Guy; Radford-Knoery, Joël; Soletchnik, Patrick

    2007-09-01

    Sediment cores were collected from April to August 2004 on tidal mudflats of the macrotidal Marennes-Oléron Bay (SW France), famous for the cultivation of Pacific oysters (Crassostrea gigas). The response of living (stained) benthic foraminifera to short-term biogeochemical disturbances in the sediment and overlying water, which may be involved in oyster summer mortality, was monitored. Short-term hypoxia occurred in early June, in conjunction with a sudden rise in temperature. In mid-June, the ammonia content of sediment porewater increased, leading to potentially maximal flux towards overlying waters. Foraminiferal assemblages, particularly in the topmost layer, were altered. Ammonia tepida was the most tolerant to temperature increase and hypoxic conditions whereas Brizalina variabilis and Haynesina germanica were sensitive to organic degradation and hypoxia. Cribroelphidium gunteri was the most opportunistic during recolonisation. Benthic foraminifera showed that short-term biochemical changes in the sediment are toxic and may be involved in the summer mortality of Pacific oysters.

  7. 49 CFR 229.69 - Side bearings.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Side bearings. 229.69 Section 229.69....69 Side bearings. (a) Friction side bearings with springs designed to carry weight may not have more than 25 percent of the springs in any one nest broken. (b) Friction side bearings may not be run in...

  8. PFR²: a curated database of planktonic foraminifera 18S ribosomal DNA as a resource for studies of plankton ecology, biogeography and evolution.

    Science.gov (United States)

    Morard, Raphaël; Darling, Kate F; Mahé, Frédéric; Audic, Stéphane; Ujiié, Yurika; Weiner, Agnes K M; André, Aurore; Seears, Heidi A; Wade, Christopher M; Quillévéré, Frédéric; Douady, Christophe J; Escarguel, Gilles; de Garidel-Thoron, Thibault; Siccha, Michael; Kucera, Michal; de Vargas, Colomban

    2015-11-01

    Planktonic foraminifera (Rhizaria) are ubiquitous marine pelagic protists producing calcareous shells with conspicuous morphology. They play an important role in the marine carbon cycle, and their exceptional fossil record serves as the basis for biochronostratigraphy and past climate reconstructions. A major worldwide sampling effort over the last two decades has resulted in the establishment of multiple large collections of cryopreserved individual planktonic foraminifera samples. Thousands of 18S rDNA partial sequences have been generated, representing all major known morphological taxa across their worldwide oceanic range. This comprehensive data coverage provides an opportunity to assess patterns of molecular ecology and evolution in a holistic way for an entire group of planktonic protists. We combined all available published and unpublished genetic data to build PFR(2), the Planktonic foraminifera Ribosomal Reference database. The first version of the database includes 3322 reference 18S rDNA sequences belonging to 32 of the 47 known morphospecies of extant planktonic foraminifera, collected from 460 oceanic stations. All sequences have been rigorously taxonomically curated using a six-rank annotation system fully resolved to the morphological species level and linked to a series of metadata. The PFR(2) website, available at http://pfr2.sb-roscoff.fr, allows downloading the entire database or specific sections, as well as the identification of new planktonic foraminiferal sequences. Its novel, fully documented curation process integrates advances in morphological and molecular taxonomy. It allows for an increase in its taxonomic resolution and assures that integrity is maintained by including a complete contingency tracking of annotations and assuring that the annotations remain internally consistent. © 2015 John Wiley & Sons Ltd.

  9. Moving beyond the age-depth model paradigm in deep-sea palaeoclimate archives: dual radiocarbon and stable isotope analysis on single foraminifera

    Science.gov (United States)

    Lougheed, Bryan C.; Metcalfe, Brett; Ninnemann, Ulysses S.; Wacker, Lukas

    2018-04-01

    Late-glacial palaeoclimate reconstructions from deep-sea sediment archives provide valuable insight into past rapid changes in ocean chemistry. Unfortunately, only a small proportion of the ocean floor with sufficiently high sediment accumulation rate (SAR) is suitable for such reconstructions using the long-standing age-depth model approach. We employ ultra-small radiocarbon (14C) dating on single microscopic foraminifera to demonstrate that the long-standing age-depth model method conceals large age uncertainties caused by post-depositional sediment mixing, meaning that existing studies may underestimate total geochronological error. We find that the age-depth distribution of our 14C-dated single foraminifera is in good agreement with existing bioturbation models only after one takes the possibility of Zoophycos burrowing into account. To overcome the problems associated with the age-depth paradigm, we use the first ever dual 14C and stable isotope (δ18O and δ13C) analysis on single microscopic foraminifera to produce a palaeoclimate time series independent of the age-depth paradigm. This new state of the art essentially decouples single foraminifera from the age-depth paradigm to provide multiple floating, temporal snapshots of ocean chemistry, thus allowing for the successful extraction of temporally accurate palaeoclimate data from low-SAR deep-sea archives. This new method can address large geographical gaps in late-glacial benthic palaeoceanographic reconstructions by opening up vast areas of previously disregarded, low-SAR deep-sea archives to research, which will lead to an improved understanding of the global interaction between oceans and climate.

  10. On a grain of sand - a microhabitat for the opportunistic agglutinated foraminifera Hemisphaerammina apta n. sp., from the early Eocene Arctic Ocean

    Science.gov (United States)

    McNeil, David H.; Neville, Lisa A.

    2018-02-01

    Hemisphaerammina apta n. sp. is an attached monothalamous agglutinated foraminifera discovered in shelf sediments of the early Eocene Arctic Ocean. It is a simple yet distinctive component of the endemic agglutinated foraminiferal assemblage that colonized the Arctic Ocean after the microfaunal turnover caused by the Paleocene-Eocene Thermal Maximum. Associated foraminifera are characterized by a high percentage of monothalamous species (up to 60 %) and are entirely agglutinated indicating a brackish (mesohaline) early Eocene Arctic Ocean. Hemisphaerammina apta occurs exclusively as individuals attached to fine detrital grains (0.2 to 1.8 mm) of sediment. It is a small species (0.06 to 0.2 mm in diameter), fine-grained, with a low hemispherical profile, no floor across the attachment area, no substantive marginal flange, no internal structures, and no aperture. Lacking an aperture, it apparently propagated and fed through minute (micrometre-sized) interstitial pores in the test wall. Attachment surfaces vary from concave to convex and rough to smooth. Grains for attachment are diverse in shape and type but are predominantly of quartz and chert. The presence of H. apta in the early Eocene was an opportunistic response to an environment with an active hydrological system (storm events). Attachment to grains of sand would provide a more stable base on a sea floor winnowed by storm-generated currents. Active transport is indicated by the relative abundance of reworked foraminifera mixed with in situ species. Contemporaneous reworking and colonization by H. apta is suggested by its attachment to a reworked specimen of Cretaceous foraminifera.

  11. Moving beyond the age–depth model paradigm in deep-sea palaeoclimate archives: dual radiocarbon and stable isotope analysis on single foraminifera

    Directory of Open Access Journals (Sweden)

    B. C. Lougheed

    2018-04-01

    Full Text Available Late-glacial palaeoclimate reconstructions from deep-sea sediment archives provide valuable insight into past rapid changes in ocean chemistry. Unfortunately, only a small proportion of the ocean floor with sufficiently high sediment accumulation rate (SAR is suitable for such reconstructions using the long-standing age–depth model approach. We employ ultra-small radiocarbon (14C dating on single microscopic foraminifera to demonstrate that the long-standing age–depth model method conceals large age uncertainties caused by post-depositional sediment mixing, meaning that existing studies may underestimate total geochronological error. We find that the age–depth distribution of our 14C-dated single foraminifera is in good agreement with existing bioturbation models only after one takes the possibility of Zoophycos burrowing into account. To overcome the problems associated with the age–depth paradigm, we use the first ever dual 14C and stable isotope (δ18O and δ13C analysis on single microscopic foraminifera to produce a palaeoclimate time series independent of the age–depth paradigm. This new state of the art essentially decouples single foraminifera from the age–depth paradigm to provide multiple floating, temporal snapshots of ocean chemistry, thus allowing for the successful extraction of temporally accurate palaeoclimate data from low-SAR deep-sea archives. This new method can address large geographical gaps in late-glacial benthic palaeoceanographic reconstructions by opening up vast areas of previously disregarded, low-SAR deep-sea archives to research, which will lead to an improved understanding of the global interaction between oceans and climate.

  12. BIOTIC (FORAMINIFERA AND THECAMOEBIANS AND ABIOTIC PARAMETERS AS PROXIES FOR IDENTIFICATION OF THE ENVIRONMENTAL HETEROGENEITY IN CAETÉ RIVER ESTUARY, AMAZON COAST, BRAZIL

    Directory of Open Access Journals (Sweden)

    Lazaro Luiz Mattos Laut1

    2016-01-01

    Full Text Available Foraminifera and thecamoebians assemblages were analyzed at Caeté River Estuary in order to identify saline gradients and intensity of human impacts. In the study area, 29 species of foraminifera typically from intertidal environments and 11 species of thecamoebians were identified. The microfaunal assemblages were characterized by low diversity, averaging 1.9 at the mouth and 0.5 near Bragança City. These values are common in transitional coastal environments along de Brazilian Coast. Statistical analysis, based on the relative abundance of species, did not reveal the presence of an estuarine gradient, which was corroborated by the physical and chemical parameters measured in the field. An increasing of sedimentary fine fraction and organic matter occurs in the intermediate region of the estuary, indicating attenuation of the stream influence. The calcareous foraminifera species were associated with high salinity, temperature and pH values. The agglutinated species were associated with muddy sediment, total organic matter and lower salinity. Four environmental compartments were identified based on biotic and abiotic analysis, but they do not represent the classic estuarine gradient, instead, they represent the differences in the freshwater supply and mangrove distance.

  13. Environmental controls on the distribution of living (stained) benthic foraminifera on the continental slope in the Campos Basin area (SW Atlantic)

    Science.gov (United States)

    Yamashita, Cintia; Mello e Sousa, Silvia Helena de; Vicente, Thaisa Marques; Martins, Maria Virgínia; Nagai, Renata Hanae; Frontalini, Fabrizio; Godoi, Sueli Susana; Napolitano, Dante; Burone, Letícia; Carreira, Renato; Figueira, Rubens Cesar Lopes; Taniguchi, Nancy Kazumi; Rezende, Carlos Eduardo de; Koutsoukos, Eduardo Apostolos Machado

    2018-05-01

    Living (stained) benthic foraminifera from deep-sea stations in the Campos Basin, southeastern Brazilian continental margin, were investigated to understand their distribution patterns and ecology, as well as the oceanographic processes that control foraminiferal distribution. Sediments were collected from 1050 m to 1950 m of water depth during the austral winter of 2003, below the Intermediate Western Boundary Current (IWBC) and the Deep Water Boundary Current (DWBC). Based on statistical analysis, vertical flux of particulate organic matter and the grain size of sediment seem to be the main factors controlling the spatial distribution of benthic foraminifera. The middle slope (1050 m deep) is characterized by relatively high foraminiferal density and a predominance of phytodetritus-feeding foraminifera such as Epistominella exigua and Globocassidulina subglobosa. The occurrence of these species seems to reflect the Brazil Current System (BCS). The above-mentioned currents are associated with the relatively high vertical flux of particulate organic matter and the prevalence of sandy sediments, respectively. The lower slope (between 1350 and 1950 m of water depth) is marked by low foraminiferal density and assemblages composed of Bolivina spp. and Brizalina spp., with low particulate organic matter flux values, muddy sediments, and more refractory organic matter. The distribution of this group seems to be related to episodic fluxes of food particles to the seafloor, which are influenced by the BCS at the surface and are deposited under low deep current activity (DWBC).

  14. Determination on the chemical composition of Ammonia beccarii shell using SEM and EDX: Preliminary study of benthic foraminifera capacity in response to anthropogenic metal contamination in coastal areas

    Science.gov (United States)

    Rositasari, R.; Suratno; Yogaswara, D.

    2018-02-01

    The use of single-celled and shelled biota, such as foraminifera that lives as benthic, in coastal environmental monitoring activity is very efficient. Several species of the Ammonia have been used as a proxy of various aquatic environmental monitoring activities. Chemical constituents screening in foraminiferal shell is a step ahead to identify the capacity of benthic foraminifera in responding to anthropogenic metal contamination in coastal water areas. The initial hypothesis of this study is the calcite test of Ammonia beccarii binds the anthropogenic metal in its shell structure and triggers the deformation test. The normal and abnormal shells of Ammonia specimens from Jakarta Bay and Batam waters are used in this study. The Ponar grab was used to sample surface sediment in Jakarta Bay and Batam waters in 2015, and the short core was used to acquire substratum sediment in Jakarta Bay in 2011.The Ammonia beccarii shell was analyzed using SEM and EDX detectors (Scanning Electron Microscope and Energy Dispersive X-ray). The shooting was performed three times in each test, i.e. in the first chamber (proloculus), the last chamber and the chamber between the two. The main building blocks of the foraminifera test are oxygen with an average weight range of 42.86 - 58.79% and carbon with an average weight range of 17.69 - 26.32%. There is a tendency for low levels of C and O elements in the abnormal tests.

  15. Superconductor bearings, flywheels and transportation

    International Nuclear Information System (INIS)

    Werfel, F N; Floegel-Delor, U; Rothfeld, R; Riedel, T; Goebel, B; Wippich, D; Schirrmeister, P

    2012-01-01

    This paper describes the present status of high temperature superconductors (HTS) and of bulk superconducting magnet devices, their use in bearings, in flywheel energy storage systems (FESS) and linear transport magnetic levitation (Maglev) systems. We report and review the concepts of multi-seeded REBCO bulk superconductor fabrication. The multi-grain bulks increase the averaged trapped magnetic flux density up to 40% compared to single-grain assembly in large-scale applications. HTS magnetic bearings with permanent magnet (PM) excitation were studied and scaled up to maximum forces of 10 kN axially and 4.5 kN radially. We examine the technology of the high-gradient magnetic bearing concept and verify it experimentally. A large HTS bearing is tested for stabilizing a 600 kg rotor of a 5 kWh/250 kW flywheel system. The flywheel rotor tests show the requirement for additional damping. Our compact flywheel system is compared with similar HTS–FESS projects. A small-scale compact YBCO bearing with in situ Stirling cryocooler is constructed and investigated for mobile applications. Next we show a successfully developed modular linear Maglev system for magnetic train operation. Each module levitates 0.25t at 10 mm distance during one-day operation without refilling LN 2 . More than 30 vacuum cryostats containing multi-seeded YBCO blocks are fabricated and are tested now in Germany, China and Brazil.

  16. Noise estimation of oil lubricated journal bearings

    International Nuclear Information System (INIS)

    Rho, Byoung Hoo; Kim, Kyung Woong

    2003-01-01

    Noise estimating procedures of oil lubricated journal bearings are presented. Nonlinear analysis of rotor-bearing system including unbalance mass of the rotor is performed in order to obtain acoustical properties of the bearing. Acoustical properties of the bearing are investigated through frequency analysis of the pressure fluctuation of the fluid film calculated from the nonlinear analysis. Noise estimating procedures presented in this paper could aid in the evaluation and understanding of acoustical properties of oil lubricated journal bearings

  17. Changes in plain bearing technology

    CERN Document Server

    Koring, Rolf

    2012-01-01

    A unique fusion of theoretical and practical knowledge, Changes in Plain Bearing Technology, by Rolf Koring, covers a meaningful range of expertise in this field.Drawing from years of experience in design development, materials selection, and their correlation to real-life part failure, this title, co-published by SAE International and expert Verlag (Germany), concentrates on hydrodynamic bearings lined with white metals, also known as Babbits.Written under the assumption that even the most mature body of knowledge can be revisited and improved, Changes in Plain Bearing Technology is a courageous and focused approach to questioning accepted test results and looking at alternative material compounds, and their application suitability.The process, which leads to innovative answers on how the technology is transforming itself to respond to new market requirements, shows how interdisciplinary thinking can recognize new potential in long-established industrial modus operandi.Tackling the highly complex issue of co...

  18. 'Dodo' and 'Baby Bear' Trenches

    Science.gov (United States)

    2008-01-01

    NASA's Phoenix Mars Lander's Surface Stereo Imager took this image on Sol 11 (June 5, 2008), the eleventh day after landing. It shows the trenches dug by Phoenix's Robotic Arm. The trench on the left is informally called 'Dodo' and was dug as a test. The trench on the right is informally called 'Baby Bear.' The sample dug from Baby Bear will be delivered to the Phoenix's Thermal and Evolved-Gas Analyzer, or TEGA. The Baby Bear trench is 9 centimeters (3.1 inches) wide and 4 centimeters (1.6 inches) deep. The Phoenix Mission is led by the University of Arizona, Tucson, on behalf of NASA. Project management of the mission is by NASA's Jet Propulsion Laboratory, Pasadena, Calif. Spacecraft development is by Lockheed Martin Space Systems, Denver.

  19. Tolerance of allogromiid Foraminifera to severely elevated carbon dioxide concentrations: Implications to future ecosystem functioning and paleoceanographic interpretations

    Science.gov (United States)

    Bernhard, Joan M.; Mollo-Christensen, Elizabeth; Eisenkolb, Nadine; Starczak, Victoria R.

    2009-02-01

    Increases in the partial pressure of carbon dioxide (pCO 2) in the atmosphere will significantly affect a wide variety of terrestrial fauna and flora. Because of tight atmospheric-oceanic coupling, shallow-water marine species are also expected to be affected by increases in atmospheric carbon dioxide concentrations. One proposed way to slow increases in atmospheric pCO 2 is to sequester CO 2 in the deep sea. Thus, over the next few centuries marine species will be exposed to changing seawater chemistry caused by ocean-atmospheric exchange and/or deep-ocean sequestration. This initial case study on one allogromiid foraminiferal species ( Allogromia laticollaris) was conducted to begin to ascertain the effect of elevated pCO 2 on benthic Foraminifera, which are a major meiofaunal constituent of shallow- and deep-water marine communities. Cultures of this thecate foraminiferan protist were used for 10-14-day experiments. Experimental treatments were executed in an incubator that controlled CO 2 (15 000; 30 000; 60 000; 90 000; 200 000 ppm), temperature and humidity; atmospheric controls (i.e., ~ 375 ppm CO 2) were executed simultaneously. Although the experimental elevated pCO 2 values are far above foreseeable surface water pCO 2, they were selected to represent the spectrum of conditions expected for the benthos if deep-sea CO 2 sequestration becomes a reality. Survival was assessed in two independent ways: pseudopodial presence/absence and measurement of adenosine triphosphate (ATP), which is an indicator of cellular energy. Substantial proportions of A. laticollaris populations survived 200 000 ppm CO 2 although the mean of the median [ATP] of survivors was statistically lower for this treatment than for that of atmospheric control specimens. After individuals that had been incubated in 200 000 ppm CO 2 for 12 days were transferred to atmospheric conditions for ~ 24 h, the [ATP] of live specimens (survivors) approximated those of the comparable atmospheric

  20. Variations of the paleo-productivity in benthic foraminifera records in MIS 3 from western South China Sea

    Science.gov (United States)

    Niu, Y.; Du, J.; Huang, B.; Chen, M.

    2010-12-01

    Understanding climate change of last glacial age as the background information of climate forecasting is particularly important in climate research. Marine Isotope Stage 3 (MIS 3, 61-24 ka B.P.) is a relative warm and unstable period in the last glacial. Millennium scale abrupt climate changes, such as Heinrich events and Dansgaard-Oeschger (D-O) cycles, are identified in this period. Research topic on the variations of monsoon during the glacial cycles, especially in MIS 3, is critical for understanding low latitude climatic change and the global paleo-environment as a whole. Fortunately, high resolution sedimentary records in western South China Sea provide us valuable materials to uncover how East Asia Summer Monsoon (EASM) system acts in a highly fluctuating climate ambient like MIS 3. Core 17954 is located in the modern summer upwelling area off the Vietnam coast in western South China Sea (SCS), its sediments record the variations of upwelling generated by EASM. In this work, we carry out paleo-ecological analyses on planktonic ( Neogloboquadrina dutertrei, Globigerina bulloides) and benthic foraminifera (Bulimina aculeate, Uvigerina peregrina, Cibicidoides wuellerstorfi, ect.) sampled from Core 17954 to investigate paleo-productivity and nutrition change of western SCS and its relation to EASM. The results show that benthic and planktonic foraminifera have similar responses to nutrition change. Various indicators of productivity on the basis of benthic foraminiferal analyses reflect an overall three stage change trend: productivity gradually increases from the beginning of MIS 3 (60-40 ka) to its maximum during 35-30 ka, and finally declines after 30 ka. There is also another important discovery, if we observe the climate change in MIS 3 as a whole, we can also find western SCS and Northern Hemisphere High latitude have strong correspondences in such changes: Heinrich events coincided with high productivity events in the western SCS. Further, the result of

  1. Benthic foraminifera as tools in interpretation of subsurface hydrocarbon fluid flow at Veslemøy High and Hola-Vesterålen areas of the Barents Sea.

    Science.gov (United States)

    Baranwal, Soma; Sauer, Simone; Knies, Jochen; Chand, Shyam; Jensen, Henning; Klug, Martin

    2014-05-01

    Relatively few studies have focused on high-latitude benthic foraminifera related to hydrocarbon seeps. In this study, we present micropaleontological data from 8 gravity cores from the Veslemøy High and 4 surface sediments (0-1cm) from Hola-Vesterålen, Norway. The study of hydrocarbon impregnation and its effect on benthic foraminfera was conducted on selected sediment samples from the calcium-rich Holocene sediments of the Veslemøy High. The assemblage of foraminifera have been identified from three regional clusters. Cluster I and II are dominated by benthic foraminifera Buccella, Cassidulina, Cibicides, Discopulvinulina, Epistominella, Pullenia and Trifarina. Cluster III is distinct with an elevated abundance of Cassidulina, Cibicides and Trifarina with significant (>5 %) occurrence of Nonionella and Uvigerina. There is no apparent dissolution on the preserved foraminifera. However, there can be differential dissolution or destruction of the more fragile (thinner-walled test) species like Epistominella, Nonionella or Pullenia while leaving behind over-represented species like Cibicides or Trifarina (both preferring coarse grained, high energy areas that can withstand permanent winnowing and redeposition) with higher preservation potential. Also, Cluster III is placed right over the underlying fault line with shallow seep-indications and thus the fluids released may have induced the dissolution of the fragile species. Moreover, the significant occurrence of benthic foraminifera Nonionella auris, and Uvigerina peregrina, in Holocene deposits of Cluster III may be indicative of environments influenced by hydrocarbon migration to the seafloor. Previous studies have reported active natural hydrocarbon seepage in the Hola area and the stable carbon and hydrogen isotopic composition of methane in the sediments suggests a predominantly thermogenic methane source. The seep-assemblage is composed of Cibicides (~60%), Cassidulina, Discanomalina, Textularia and

  2. Growth, chamber building rate and reproduction time of Palaeonummulites venosus (Foraminifera) under natural conditions

    Science.gov (United States)

    Kinoshita, Shunichi; Eder, Wolfgang; Wöger, Julia; Hohenegger, Johann; Briguglio, Antonino

    2017-12-01

    We investigated the symbiont-bearing benthic foraminifer Palaeonummulites venosus to determine the chamber building rate (CBR), test diameter increase rate (DIR), reproduction time and longevity using the `natural laboratory' approach. This is based on the decomposition of monthly obtained frequency distributions of chamber number and test diameter into normally distributed components. Test measurements were taken using MicroCT. The shift of the mean and standard deviation of component parameters during the 15-month investigation period was used to calculate Michaelis-Menten functions applied to estimate the averaged CBR and DIR under natural conditions. The individual dates of birth were estimated using the inverse averaged CBR and the inverse DIR fitted by the individual chamber number or the individual test diameter at the sampling date. Distributions of frequencies and densities (i.e., frequency divided by sediment weight) based on both CBR and DIR revealed continuous reproduction throughout the year with two peaks, a stronger one in June determined as the onset of the summer generation (generation 1) and a weaker one in November determined as the onset of the winter generation (generation 2). This reproduction scheme explains the presence of small and large specimens in the same sample. Longevity, calculated as the maximum difference in days between the individual's birth date and the sampling date, is approximately 1.5 yr, an estimation obtained by using both CBR and DIR.

  3. Discovery of Orbitolinids (Foraminifera) at Lebyin, Thazi Township, Myanmar: Its Stratigraphic and Paleogeographic Significance

    International Nuclear Information System (INIS)

    Zaw Win; Pe Maung Than; Min Swe

    2001-07-01

    The purpose of this paper is to present the results of preliminary assessment on the orbitolinids discovered for the first time from an isolated hillock (locally known as Peinyoin Hill) situated at just northwest of Lebyin village (lying on the Thazi-Shwenyaung Rail Road), and from the limestone lenses embedded within a sequence of tuffaceous sandstone, mudstone and conglomerates that is exposed on the west of the Myit-thar Stream. The present preliminary examination reveals that the orbitolinid fauna at the limestone hillock consists of Paracoskinolina cf. sunnilandensis Iraqia sp., and Simplorbitolina spp., indicating an early Cretaceous age (probably Aptian-Albian). On the other hand, the limestone lenses exposed on the west of the Myit-thar Stream bear Iraqia thailandensis (=Haurania thailandensis Kemper]. From this faunal evidence and prevailing lithostratigraphic characteristics, it has reached to the final conclusion that these controversial outcrops are no longer needed to be lumped in the Late Paleozoic Lebyin Group in the Plateau Limestone Group, but must be designated as a southern continuation of the Pan Laung Formation of Jurassic-Cretaceous age. (author)

  4. The correct "ball bearings" data.

    Science.gov (United States)

    Caroni, C

    2002-12-01

    The famous data on fatigue failure times of ball bearings have been quoted incorrectly from Lieblein and Zelen's original paper. The correct data include censored values, as well as non-fatigue failures that must be handled appropriately. They could be described by a mixture of Weibull distributions, corresponding to different modes of failure.

  5. Little Bear Fire Summary Report

    Science.gov (United States)

    Sarah McCaffrey; Melanie Stidham; Hannah. Brenkert-Smith

    2013-01-01

    In June 2012, immediately after the Little Bear Fire burned outside Ruidoso, New Mexico, a team of researchers interviewed fire managers, local personnel, and residents to understand perceptions of the event itself, communication, evacuation, and pre-fire preparedness. The intensity of fire behavior and resulting loss of 242 homes made this a complex fire with a...

  6. Satellite monitoring of black bear.

    Science.gov (United States)

    Craighead, J. J.; Craighead, F. C., Jr.; Varney, J. R.; Cote, C. E.

    1971-01-01

    Description of a feasibility experiment recently performed to test the use of a satellite system for telemetering environmental and physiological data from the winter den of a 'hibernating' black bear, Ursus americanus. The instrumentation procedure and evaluations of the equipment performance and sensory data obtained are discussed in detail.

  7. Glomospirella cantabrica n. sp., and other benthic foraminifera from Lower Cretaceous Urgonian-type carbonates of Cantabria, Spain: Biostratigraphic implications

    Energy Technology Data Exchange (ETDEWEB)

    Schlagintweit, F.; Rosales, I.; Najarro, M.

    2016-07-01

    A new benthic foraminifer is described as Glomospirella cantabrica n. sp. from several sections of the upper Aptian Reocín Formation and one occurrence from the lowermost Albian Las Peñosas Formation of Cantabria (northern Spain). It represents a rather large-sized Glomospirella, with up to eight planispiral whorls, observed in lagoonal wackestones and packstones. The upper Aptian (upper Gargasian–Clansayesian) age is indicated by the co-occurrence with other benthic foraminifera, i.e. orbitolinids. Further biostratigraphic data of the Aptian-p.p. Albian shallow-water carbonates of the North Cantabrian Basin is provided. The rareness of dasycladalean green algae in these deposits is also highlighted. The resulting stratigraphic and biostratigraphic scheme is integrated in a framework of depositional sequences of the North Cantabrian Basin and compared with the sequential schemes of other areas of the Basque-Cantabrian Basin and the Iberian Chain. Similitudes suggest that these depositional sequences are related to global sea-level changes. (Author)

  8. Characterizing the variability of benthic foraminifera in the northeastern Gulf of Mexico following the Deepwater Horizon event (2010-2012).

    Science.gov (United States)

    Schwing, P T; O'Malley, B J; Romero, I C; Martínez-Colón, M; Hastings, D W; Glabach, M A; Hladky, E M; Greco, A; Hollander, D J

    2017-01-01

    Following the Deepwater Horizon (DWH) event in 2010 subsurface hydrocarbon intrusions (1000-1300 m) and an order of magnitude increase in flocculent hydrocarbon deposition caused increased concentrations of hydrocarbons in continental slope sediments. This study sought to characterize the variability [density, Fisher's alpha (S), equitability (E), Shannon (H)] of benthic foraminifera following the DWH event. A series of sediment cores were collected at two sites in the northeastern Gulf of Mexico from 2010 to 2012. At each site, three cores were utilized for benthic faunal analysis, organic geochemistry, and redox metal chemistry, respectively. The surface intervals (∼0-10 mm) of the sedimentary records collected in December 2010 at DSH08 and February 2011 at PCB06 were characterized by significant decreases in foraminiferal density, S, E, and H, relative to the down-core intervals as well as previous surveys. Non-metric multidimensional scaling (nMDS) analysis suggested that a 3-fold increase in polycyclic aromatic hydrocarbon (PAH) concentration in the surface interval, relative to the down-core interval, was the environmental driver of benthic foraminiferal variability. These records suggested that the benthic foraminiferal recovery time, following an event such as the DWH, was on the order of 1-2 years.

  9. Paleocene to Middle Miocene planktic foraminifera of the southwestern Salisbury Embayment, Virginia and Maryland: biostratigraphy, allostratigraphy, and sequence stratigraphy

    Science.gov (United States)

    Poag, C.W.; Commeau, J.A.

    1995-01-01

    The Paleocene to Middle Miocene sedimentary fill of the southwestern Salisbury Embayment contains a fragmental depositional record, interrupted by numerous local diastems and regional unconformities. Using planktic foraminiferal biostratigraphy, 15 unconformity-bounded depositional units have been identified, assigned to six formations and seven alloformations previously recognized in the embayment. The units correlate with second- and third-order sequences of the Exxon sequence stratigraphy model, and include transgressive and highstand systems tracts. Alloformation, formation, and sequence boundaries are marked by abrupt, scoured, burrowed, erosional surfaces, which display lag deposits, biostratigraphic gaps, and intense reworking of microfossils above and below the boundaries.Paleocene deposits represent the upper parts of upper Pleocene Biochronozones P4 and P5, and rest uncomformably  on Cretaceous sedimentary beds of various ages (Maastrichtian to Albian). Lower Eocene deposits represent parts of Biochronozones P6 and P9. Middle Eocene strata represent mainly parts of Biochronozones P11, P12, and P14. Upper Eocene sediments include parts of Biochronozones P15, P16, and P17. Oligocene deposits encompass parts of Biochronozones. N4b to N7 undifferentiated, P21a, and, perhaps, N4a. Lower Miocene deposits encompass parts of Biochronozones N4b to N7 undifferentiated. Middle Miocene strata represent mainly parts of Biochronorones N8, N9, and N10.Nine plates of scanning electron micrographs illustrate the principal planktic foraminifera used to establish the biostratigraphic framework. Two new informal formine of Praeterenuitella praegemma Li, 1987, are introduced.

  10. New evidence on the origin of non-spinose pitted-cancellate species of the early Danian planktonic foraminifera

    Science.gov (United States)

    Arenillas, Ignacio; Arz, Jose Antonio

    2013-06-01

    Intermediate forms identified in some of the most continuous lower Danian sections allow a better understanding of the origin and evolution of pitted (Globanomalina) and cancellate (Praemurica) planktonic foraminifera. Both Globanomalina and Praemurica are part of a major Paleocene lineage, namely the "non-spinose lineage", which started to diverge in the early Danian. Transitional specimens strongly suggest the evolution from Parvularugoglobigerina to Globanomalina, and then to Praemurica. These evolutionary turnovers were quite rapid (probably lasting less than 10 kyr), and seem to have begun in the time equivalent of the lower part of the E. simplicissima Subzone, namely the middle part of the standard Zone Pa. The initial evolutionary trends within this non-spinose lineage were the increase of test size and lip thickness, and the evolution from tiny pore-murals to large pore-pits, and from smooth to pitted and finally cancellate walls. Biostratigraphic data suggest that evolution of the wall texture preceded the morphological evolution within each genus. The oldest species of both Globanomalina and Praemurica, namely G. archeocompressa and Pr. taurica, initially retained the external morphology of the ancestral Parvularugoglobigerina eugubina. Since their divergence, Globanomalina and Praemurica followed a separate evolutionary path, evolving into morphologically different species.

  11. Phylogeography of the tropical planktonic foraminifera lineage globigerinella reveals isolation inconsistent with passive dispersal by ocean currents.

    Directory of Open Access Journals (Sweden)

    Agnes K M Weiner

    Full Text Available Morphologically defined species of marine plankton often harbor a considerable level of cryptic diversity. Since many morphospecies show cosmopolitan distribution, an understanding of biogeographic and evolutionary processes at the level of genetic diversity requires global sampling. We use a database of 387 single-specimen sequences of the SSU rDNA of the planktonic foraminifera Globigerinella as a model to assess the biogeographic and phylogenetic distributions of cryptic diversity in marine microplankton on a global scale. Our data confirm the existence of multiple, well isolated genetic lineages. An analysis of their abundance and distribution indicates that our sampling is likely to approximate the actual total diversity. Unexpectedly, we observe an uneven allocation of cryptic diversity among the phylogenetic lineages. We show that this pattern is neither an artifact of sampling intensity nor a function of lineage age. Instead, we argue that it reflects an ongoing speciation process in one of the three major lineages. Surprisingly, four of the six genetic types in the hyperdiverse lineage are biogeographically restricted to the Indopacific. Their mutual co-occurrence and their hierarchical phylogenetic structure provide no evidence for an origin through sudden habitat fragmentation and their limitation to the Indopacific challenges the view of a global gene flow within the warm-water provinces. This phenomenon shows that passive dispersal is not sufficient to describe the distribution of plankton diversity. Rather, these organisms show differentiated distribution patterns shaped by species interactions and reflecting phylogenetic contingency with unique histories of diversification rates.

  12. Phylogeography of the tropical planktonic foraminifera lineage globigerinella reveals isolation inconsistent with passive dispersal by ocean currents.

    Science.gov (United States)

    Weiner, Agnes K M; Weinkauf, Manuel F G; Kurasawa, Atsushi; Darling, Kate F; Kucera, Michal; Grimm, Guido W

    2014-01-01

    Morphologically defined species of marine plankton often harbor a considerable level of cryptic diversity. Since many morphospecies show cosmopolitan distribution, an understanding of biogeographic and evolutionary processes at the level of genetic diversity requires global sampling. We use a database of 387 single-specimen sequences of the SSU rDNA of the planktonic foraminifera Globigerinella as a model to assess the biogeographic and phylogenetic distributions of cryptic diversity in marine microplankton on a global scale. Our data confirm the existence of multiple, well isolated genetic lineages. An analysis of their abundance and distribution indicates that our sampling is likely to approximate the actual total diversity. Unexpectedly, we observe an uneven allocation of cryptic diversity among the phylogenetic lineages. We show that this pattern is neither an artifact of sampling intensity nor a function of lineage age. Instead, we argue that it reflects an ongoing speciation process in one of the three major lineages. Surprisingly, four of the six genetic types in the hyperdiverse lineage are biogeographically restricted to the Indopacific. Their mutual co-occurrence and their hierarchical phylogenetic structure provide no evidence for an origin through sudden habitat fragmentation and their limitation to the Indopacific challenges the view of a global gene flow within the warm-water provinces. This phenomenon shows that passive dispersal is not sufficient to describe the distribution of plankton diversity. Rather, these organisms show differentiated distribution patterns shaped by species interactions and reflecting phylogenetic contingency with unique histories of diversification rates.

  13. Genomic evidence of geographically widespread effect of gene flow from polar bears into brown bears

    OpenAIRE

    Cahill, James A; Stirling, Ian; Kistler, Logan; Salamzade, Rauf; Ersmark, Erik; Fulton, Tara L; Stiller, Mathias; Green, Richard E; Shapiro, Beth

    2015-01-01

    © 2014 The Authors. Molecular Ecology Published by John Wiley & Sons Ltd. Polar bears are an arctic, marine adapted species that is closely related to brown bears. Genome analyses have shown that polar bears are distinct and genetically homogeneous in comparison to brown bears. However, these analyses have also revealed a remarkable episode of polar bear gene flow into the population of brown bears that colonized the Admiralty, Baranof and Chichagof islands (ABC islands) of Alaska. Here, we...

  14. TOOL ASSEMBLY WITH BI-DIRECTIONAL BEARING

    Science.gov (United States)

    Longhurst, G.E.

    1961-07-11

    A two-direction motion bearing which is incorporated in a refueling nuclear fuel element trsnsfer tool assembly is described. A plurality of bi- directional bearing assembliesare fixed equi-distantly about the circumference of the transfer tool assembly to provide the tool assembly with a bearing surface- for both axial and rotational motion. Each bi-directional bearing assembly contains a plurality of circumferentially bulged rollers mounted in a unique arrangement which will provide a bearing surface for rotational movement of the tool assembly within a bore. The bi-direc tional bearing assembly itself is capable of rational motion and thus provides for longitudinal movement of the tool assembly.

  15. Estimating Wear Of Installed Ball Bearings

    Science.gov (United States)

    Keba, John E.; Mcvey, Scott E.

    1993-01-01

    Simple inspection and measurement technique makes possible to estimate wear of balls in ball bearing, without removing bearing from shaft on which installed. To perform measurement, one observes bearing cage while turning shaft by hand to obtain integral number of cage rotations and to measure, to nearest 2 degrees, number of shaft rotations producing cage rotations. Ratio between numbers of cages and shaft rotations depends only on internal geometry of bearing and applied load. Changes in turns ratio reflect changes in internal geometry of bearing provided measurements made with similar bearing loads. By assuming all wear occurs on balls, one computes effective value for this wear from change in turns ratio.

  16. EFFECT OF CLEARANCE THE BALL BEARINGS ON INCORRECT WORK OF THREE-SUPORT BEARING SHAFT

    Directory of Open Access Journals (Sweden)

    Jarosław KACZOR

    2014-06-01

    Full Text Available Durability deep groove ball bearings depends on factors (called attributes design, technological and operational. Among the design features one of the most important is play in the bearings. Polish Norm shows five groups of looseness in the bearings, in which the play range from 0 to 105 microns. Manufacturers of rolling bearings they only play group, which has a bearing data, without giving the exact value of the slack. Aim of this study is to determine how it affects the play in the bearings to work three-bearing shafts, including elasticity and resilience three-bearing shafts.

  17. Journal and Wave Bearing Impedance Calculation Software

    Science.gov (United States)

    Hanford, Amanda; Campbell, Robert

    2012-01-01

    The wave bearing software suite is a MALTA application that computes bearing properties for user-specified wave bearing conditions, as well as plain journal bearings. Wave bearings are fluid film journal bearings with multi-lobed wave patterns around the circumference of the bearing surface. In this software suite, the dynamic coefficients are outputted in a way for easy implementation in a finite element model used in rotor dynamics analysis. The software has a graphical user interface (GUI) for inputting bearing geometry parameters, and uses MATLAB s structure interface for ease of interpreting data. This innovation was developed to provide the stiffness and damping components of wave bearing impedances. The computational method for computing bearing coefficients was originally designed for plain journal bearings and tilting pad bearings. Modifications to include a wave bearing profile consisted of changing the film thickness profile given by an equation, and writing an algorithm to locate the integration limits for each fluid region. Careful consideration was needed to implement the correct integration limits while computing the dynamic coefficients, depending on the form of the input/output variables specified in the algorithm.

  18. Stable isotopes to detect food-conditioned bears and to evaluate human-bear management

    Science.gov (United States)

    Hopkins, John B.; Koch, Paul L.; Schwartz, Charles C.; Ferguson, Jake M.; Greenleaf, Schuyler S.; Kalinowski, Steven T.

    2012-01-01

    We used genetic and stable isotope analysis of hair from free-ranging black bears (Ursus americanus) in Yosemite National Park, California, USA to: 1) identify bears that consume human food, 2) estimate the diets of these bears, and 3) evaluate the Yosemite human–bear management program. Specifically, we analyzed the isotopic composition of hair from bears known a priori to be food-conditioned or non-food-conditioned and used these data to predict whether bears with an unknown management status were food-conditioned (FC) or non-food-conditioned (NFC). We used a stable isotope mixing model to estimate the proportional contribution of natural foods (plants and animals) versus human food in the diets of FC bears. We then used results from both analyses to evaluate proactive (population-level) and reactive (individual-level) human–bear management, and discussed new metrics to evaluate the overall human–bear management program in Yosemite. Our results indicated that 19 out of 145 (13%) unknown bears sampled from 2005 to 2007 were food-conditioned. The proportion of human food in the diets of known FC bears likely declined from 2001–2003 to 2005–2007, suggesting proactive management was successful in reducing the amount of human food available to bears. In contrast, reactive management was not successful in changing the management status of known FC bears to NFC bears, or in reducing the contribution of human food to the diets of FC bears. Nine known FC bears were recaptured on 14 occasions from 2001 to 2007; all bears were classified as FC during subsequent recaptures, and human–bear management did not reduce the amount of human food in the diets of FC bears. Based on our results, we suggest Yosemite continue implementing proactive human–bear management, reevaluate reactive management, and consider removing problem bears (those involved in repeated bear incidents) from the population.

  19. Technology development for indigenous water lubricated bearings

    International Nuclear Information System (INIS)

    Limaye, P.K.; Soni, N.L.; Agrawal, R.G.

    2010-01-01

    Water Lubricated Bearings (WLB) are used in various mechanisms of fuel handling systems of PHWRs and AHWR. Availability and random failures of these bearings was a major factor in refuelling operations. Indigenous development of these bearings was taken up and 7 types of antifriction bearings in various sizes (totaling 37 variants) for PHWR, AHWR and Dhruva applications were successfully developed. This paper deals with various aspects of WLB development. (author)

  20. Research In Diagnosing Bearing Defects From Vibrations

    Science.gov (United States)

    Zoladz, T.; Earhart, E.; Fiorucci, T.

    1995-01-01

    Report describes research in bearing-defect signature analysis - use of vibration-signal analysis to diagnose defects in roller and ball bearings. Experiments performed on bearings in good condition and other bearings in which various parts scratched to provide known defects correlated with vibration signals. Experiments performed on highly instrumented motor-driven rotor assembly at speeds up to 10,050 r/min, using accelerometers, velocity probes, and proximity sensors mounted at various locations on assembly to measure vibrations.

  1. Cool Polar Bears: Dabbing on the Texture

    Science.gov (United States)

    O'Connell, Jean

    2011-01-01

    In this article, the author describes how her second-graders created their cool polar bears. The students used the elements of shape and texture to create the bears. They used Monet's technique of dabbing paint so as to give the bear some texture on his fur.

  2. 49 CFR 229.64 - Plain bearings.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Plain bearings. 229.64 Section 229.64 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL RAILROAD ADMINISTRATION....64 Plain bearings. A plain bearing box shall contain visible free oil and may not be cracked to the...

  3. Bearing-Mounting Concept Accommodates Thermal Expansion

    Science.gov (United States)

    Nespodzany, Robert; Davis, Toren S.

    1995-01-01

    Pins or splines allow radial expansion without slippage. Design concept for mounting rotary bearing accommodates differential thermal expansion between bearing and any structure(s) to which bearing connected. Prevents buildup of thermal stresses by allowing thermal expansion to occur freely but accommodating expansion in such way not to introduce looseness. Pin-in-slot configuration also maintains concentricity.

  4. Bears and pipeline construction in Alaska

    Energy Technology Data Exchange (ETDEWEB)

    Follmann, E.H.; Hechtel, J.L. (Univ. of Alaska Fairbanks, AK (USA))

    1990-06-01

    Serious problems were encountered with bears during construction of the 1274-km trans-Alaska oil pipeline between Prudhoe Bay and Valdez. This multi-billion-dollar project traversed both black bear (Ursus americanus Pallas) and grizzly bear (U. arctos L.) habitat throughtout its entire length. Plans for dealing with anticipated problems with bears were often inadequate. Most (71%) problems occurred north of the Yukon River in a previously roadless wilderness where inadequate refuse disposal and widespread animal feeding created dangerous situations. Of the 192 officially reported bear problems associated with the Trans-Alaska Pipeline System (TAPS) (1971-1979), about 65% involved the presence of bears in camps or dumps, 13% the feeding of bears on garbage or handouts, 10% property damage or economic loss, 7% bears under and in buildings, and only 5% charges by bears. Remarkably, no bear-related injuries were reported, suggesting that bears became accustomed to people and did not regard them as a threat. Following construction of the TAPS there have been proposals for pipelines to transport natural gas from Prudhoe Bay to southern and Pacific-rim markets. Based on past experience, some animal control measures were developed during the planning phase for the authorized gas pipeline route in Alaska. Fences installed around 100-person survey camps were found to be effective in deterring bears in two traditionally troublesome areas. 16 refs., 7 figs., 1 tab.

  5. Fractal analysis of polar bear hairs

    Directory of Open Access Journals (Sweden)

    Wang Qing-Li

    2015-01-01

    Full Text Available Hairs of a polar bear (Ursus maritimus are of superior properties such as the excellent thermal protection. Why do polar bears can resist such cold environment? The paper concludes that its fractal porosity plays an important role, and its fractal dimensions are very close to the golden mean, 1.618, revealing the possible optimal structure of polar bear hair.

  6. 36 CFR 13.1236 - Bear orientation.

    Science.gov (United States)

    2010-07-01

    ... 36 Parks, Forests, and Public Property 1 2010-07-01 2010-07-01 false Bear orientation. 13.1236 Section 13.1236 Parks, Forests, and Public Property NATIONAL PARK SERVICE, DEPARTMENT OF THE INTERIOR... Developed Area § 13.1236 Bear orientation. All persons visiting the BCDA must receive an NPS-approved Bear...

  7. 14 CFR 29.623 - Bearing factors.

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Bearing factors. 29.623 Section 29.623... STANDARDS: TRANSPORT CATEGORY ROTORCRAFT Design and Construction General § 29.623 Bearing factors. (a... subject to pounding or vibration, must have a bearing factor large enough to provide for the effects of...

  8. 14 CFR 27.623 - Bearing factors.

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Bearing factors. 27.623 Section 27.623... STANDARDS: NORMAL CATEGORY ROTORCRAFT Design and Construction General § 27.623 Bearing factors. (a) Except... subject to pounding or vibration, must have a bearing factor large enough to provide for the effects of...

  9. 14 CFR 25.623 - Bearing factors.

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Bearing factors. 25.623 Section 25.623... STANDARDS: TRANSPORT CATEGORY AIRPLANES Design and Construction General § 25.623 Bearing factors. (a) Except... subject to pounding or vibration, must have a bearing factor large enough to provide for the effects of...

  10. 14 CFR 23.623 - Bearing factors.

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Bearing factors. 23.623 Section 23.623... Bearing factors. (a) Each part that has clearance (free fit), and that is subject to pounding or vibration, must have a bearing factor large enough to provide for the effects of normal relative motion. (b) For...

  11. The BEAR Beamline at Elettra

    International Nuclear Information System (INIS)

    Nannarone, S.; Pasquali, L.; Selvaggi, G.; Borgatti, F.; DeLuisa, A.; Doyle, B.P.; Gazzadi, G.C.; Giglia, A.; Finetti, P.; Pedio, M.; Mahne, N.; Naletto, G.; Pelizzo, M.G.; Tondello, G.

    2004-01-01

    The BEAR (Bending Magnet for Emission Absorption and Reflectivity) beamline is installed at the right exit of the 8.1 bending magnet at ELETTRA. The beamline - in operation since January 2003 - delivers linear and circularly polarized radiation in the 5 - 1600 eV energy range. The experimental station is composed of a UHV chamber for reflectivity, absorption, fluorescence and angle resolved photoemission measurements and a UHV chamber for in-situ sample preparation

  12. BEAR

    DEFF Research Database (Denmark)

    Houmøller, Sabina Storbjerg; Wolff, Anne; Hougaard, Dan Dupont

    2017-01-01

    profiling and fitting strategies. Data from 2000 patients are collected from the departments of Audiology in Odense and Aalborg University Hospital. Some of the registered variables include gender, age, and health related questions, noise exposure and whether they are suffering from tinnitus. The database...... subgroups of HA users, including experienced versus new HA users will be made. Previous noise exposure and the relation to the occurrence of tinnitus will be investigated as well....

  13. Delayed recolonization of foraminifera in a suddenly flooded tidal (former freshwater) marsh in Oregon (USA): Implications for relative sea-level reconstructions

    Science.gov (United States)

    Milker, Yvonne; Horton, Benjamin P.; Khan, Nicole S.; Nelson, Alan R.; Witter, Robert C.; Engelhart, Simon E.; Ewald, Michael; Brophy, Laura; Bridgeland, William T.

    2016-04-01

    Stratigraphic sequences beneath salt marshes along the U.S. Pacific Northwest coast preserve 7000 years of plate-boundary earthquakes at the Cascadia subduction zone. The sequences record rapid rises in relative sea level during regional coseismic subsidence caused by great earthquakes and gradual falls in relative sea level during interseismic uplift between earthquakes. These relative sea-level changes are commonly quantified using foraminiferal transfer functions with the assumption that foraminifera rapidly recolonize salt marshes and adjacent tidal flats following coseismic subsidence. The restoration of tidal inundation in the Ni-les'tun unit (NM unit) of the Bandon Marsh National Wildlife Refuge (Oregon), following extensive dike removal in August 2011, allowed us to directly observe changes in foraminiferal assemblages that occur during rapid "coseismic" (simulated by dike removal with sudden tidal flooding) and "interseismic" (stabilization of the marsh following flooding) relative sea-level changes analogous to those of past earthquake cycles. We analyzed surface sediment samples from 10 tidal stations at the restoration site (NM unit) from mudflat to high marsh, and 10 unflooded stations in the Bandon Marsh control site. Samples were collected shortly before and at 1- to 6-month intervals for 3 years after tidal restoration of the NM unit. Although tide gauge and grain-size data show rapid restoration of tides during approximately the first 3 months after dike removal, recolonization of the NM unit by foraminifera was delayed at least 10 months. Re-establishment of typical tidal foraminiferal assemblages, as observed at the control site, required 31 months after tidal restoration, with Miliammina fusca being the dominant pioneering species. If typical of past recolonizations, this delayed foraminiferal recolonization affects the accuracy of coseismic subsidence estimates during past earthquakes because significant postseismic uplift may shortly follow

  14. Scaling laws for radial foil bearings

    Science.gov (United States)

    Honavara Prasad, Srikanth

    The effects of fluid pressurization, structural deformation of the compliant members and heat generation in foil bearings make the design and analysis of foil bearings very complicated. The complex fluid-structural-thermal interactions in foil bearings also make modeling efforts challenging because these phenomena are governed by highly non-linear partial differential equations. Consequently, comparison of various bearing designs require detailed calculation of the flow fields (velocities, pressures), bump deflections (structural compliance) and heat transfer phenomena (viscous dissipation in the fluid, frictional heating, temperature profile etc.,) resulting in extensive computational effort (time/hardware). To obviate rigorous computations and aid in feasibility assessments of foil bearings of various sizes, NASA developed the "rule of thumb" design guidelines for estimation of journal bearing load capacity. The guidelines are based on extensive experimental data. The goal of the current work is the development of scaling laws for radial foil bearings to establish an analytical "rule of thumb" for bearing clearance and bump stiffness. The use of scale invariant Reynolds equation and experimentally observed NASA "rule of thumb" yield scale factors which can be deduced from first principles. Power-law relationships between: a. Bearing clearance and bearing radius, and b. bump stiffness and bearing radius, are obtained. The clearance and bump stiffness values obtained from scaling laws are used as inputs for Orbit simulation to study various cases. As the clearance of the bearing reaches the dimensions of the material surface roughness, asperity contact breaks the fluid film which results in wear. Similarly, as the rotor diameter increases (requiring larger bearing diameters), the load capacity of the fluid film should increase to prevent dry rubbing. This imposes limits on the size of the rotor diameter and consequently bearing diameter. Therefore, this thesis aims

  15. Fossil and Genetic Evidence for the Polyphyletic Nature of the Planktonic Foraminifera "Globigerinoides", and Description of the New Genus Trilobatus

    Science.gov (United States)

    Spezzaferri, Silvia; Kucera, Michal; Pearson, Paul Nicholas; Wade, Bridget Susan; Rappo, Sacha; Poole, Christopher Robert; Morard, Raphaël; Stalder, Claudio

    2015-01-01

    Planktonic foraminifera are one of the most abundant and diverse protists in the oceans. Their utility as paleo proxies requires rigorous taxonomy and comparison with living and genetically related counterparts. We merge genetic and fossil evidence of “Globigerinoides”, characterized by supplementary apertures on spiral side, in a new approach to trace their “total evidence phylogeny” since their first appearance in the latest Paleogene. Combined fossil and molecular genetic data indicate that this genus, as traditionally understood, is polyphyletic. Both datasets indicate the existence of two distinct lineages that evolved independently. One group includes “Globigerinoides” trilobus and its descendants, the extant “Globigerinoides” sacculifer, Orbulina universa and Sphaeroidinella dehiscens. The second group includes the Globigerinoides ruber clade with the extant G. conglobatus and G. elongatus and ancestors. In molecular phylogenies, the trilobus group is not the sister taxon of the ruber group. The ruber group clusters consistently together with the modern Globoturborotalita rubescens as a sister taxon. The re-analysis of the fossil record indicates that the first “Globigerinoides” in the late Oligocene are ancestral to the trilobus group, whereas the ruber group first appeared at the base of the Miocene with representatives distinct from the trilobus group. Therefore, polyphyly of the genus "Globigerinoides" as currently defined can only be avoided either by broadening the genus concept to include G. rubescens and a large number of fossil species without supplementary apertures, or if the trilobus group is assigned to a separate genus. Since the former is not feasible due to the lack of a clear diagnosis for such a broad genus, we erect a new genus Trilobatus for the trilobus group (type species Globigerina triloba Reuss) and amend Globoturborotalita and Globigerinoides to clarify morphology and wall textures of these genera. In the new

  16. Relationships Between Temperature, pH, and Crusting on Mg/Ca Ratios in Laboratory-Grown Neogloboquadrina Foraminifera

    Science.gov (United States)

    Davis, Catherine V.; Fehrenbacher, Jennifer S.; Hill, Tessa M.; Russell, Ann D.; Spero, Howard J.

    2017-11-01

    Mg/Ca ratio paleothermometry in foraminifera is an important tool for the reconstruction and interpretation of past environments. However, existing Mg/Ca:temperature relationships for planktic species inhabiting middle- and high-latitude environments are limited by a lack of information about the development and impact of low-Mg/Ca ratio "crusts" and the influence of the carbonate system on Mg/Ca ratios in these groups. To address this, we cultured individual specimens of Neogloboquadrina incompta and Neogloboquadrina pachyderma in seawater across a range of temperature (6°-12°C) and pH (7.4-8.2). We found by laser ablation inductively couple mass spectrometry analyses of shells that culture-grown crust calcite in N. incompta had a lower Mg/Ca ratio than ontogenetic calcite formed at the same temperature, suggesting that temperature is not responsible for the low-Mg/Ca ratio of neogloboquadrinid crusts. The Mg/Ca:temperature relationship for ontogenetic calcite in N. incompta was consistent with the previously published culture-based relationship, and no significant relationship was found between Mg/Ca ratios and pH in this species. However, the Mg/Ca ratio in laboratory-cultured N. pachyderma was much higher than that reported in previous core top and sediment trap samples, due to lack of crust formation in culture. Application of our ontogenetic calcite-specific Mg/Ca:temperature relationships to fossil N. pachyderma and N. incompta from five intervals in cores from the Santa Barbara Basin and the Bering Sea shows that excluding crust calcite in fossil specimens may improve Mg/Ca-based temperature estimates.

  17. Improvement of journal bearing operation at heavy misalignment using bearing flexibility and compliant liners

    DEFF Research Database (Denmark)

    Thomsen, Kim; Klit, Peder

    2012-01-01

    A flexure journal bearing design is proposed that will improve operational behaviour of a journal bearing at pronounced misalignment. Using a thermoelastohydrodynamic model, it is shown that the proposed flexure journal bearing has vastly increased the hydrodynamic performance compared to the stiff...... bearing when misaligned. The hydrodynamic performance is evaluated on lubricant film thickness, pressure and temperature. Furthermore, the influence of a compliant bearing liner is investigated and it is found that it increases the hydrodynamic performance when applied to a stiff bearing, whereas...... the liner has practically no influence on the flexure journal bearing's performance....

  18. A motor with superconducting magnetic bearings

    International Nuclear Information System (INIS)

    Gladun, A.; Stoye, P.; Verges, P.; Gawalek, W.; Habisreuther, T.; Goernert, P.

    1993-01-01

    Superconducting bearings may be one of the most promising near term applications of HTSC. For use at liquid nitrogen temperature and below, they offer the advantage of lower energy consumption and higher reliability. Different bearing configurations have been proposed. But in order to substitute for conventional bearings a further increase in the critical current density of the superconductor and improved bearing concepts are necessary. For this it is necessary to take into account the peculiarities of the interaction between permanent magnets and bulk superconductors. As a contribution to this programme we present the model of a motor with superconducting magnetic bearings. (orig.)

  19. [Advances in studies on bear bile powder].

    Science.gov (United States)

    Zhou, Chao-fan; Gao, Guo-jian; Liu, Ying

    2015-04-01

    In this paper, a detailed analysis was made on relevant literatures about bear bile powder in terms of chemical component, pharmacological effect and clinical efficacy, indicating bear bile powder's significant pharmacological effects and clinical application in treating various diseases. Due to the complex composition, bear bile powder is relatively toxic. Therefore, efforts shall be made to study bear bile powder's pharmacological effects, clinical application, chemical composition and toxic side-effects, with the aim to provide a scientific basis for widespread reasonable clinical application of bear bile powder.

  20. Valve assembly having remotely replaceable bearings

    International Nuclear Information System (INIS)

    Johnson, E.R.; Tanner, D.E.

    1980-01-01

    A valve assembly having remotely replaceable bearings is disclosed wherein a valve disc is supported within a flow duct for rotation about a pair of axially aligned bearings, one of which is carried by a spindle received within a diametral bore in the valve disc, and the other of which is carried by a bearing support block releasably mounted on the duct circumferentially of an annular collar on the valve disc coaxial with its diametrical bore. The spindle and bearing support block are adapted for remote removal to facilitate servicing or replacement of the valve disc support bearings

  1. Ball Bearing Analysis with the ORBIS Tool

    Science.gov (United States)

    Halpin, Jacob D.

    2016-01-01

    Ball bearing design is critical to the success of aerospace mechanisms. Key bearing performance parameters, such as load capability, stiffness, torque, and life all depend on accurate determination of the internal load distribution. Hence, a good analytical bearing tool that provides both comprehensive capabilities and reliable results becomes a significant asset to the engineer. This paper introduces the ORBIS bearing tool. A discussion of key modeling assumptions and a technical overview is provided. Numerous validation studies and case studies using the ORBIS tool are presented. All results suggest the ORBIS code closely correlates to predictions on bearing internal load distributions, stiffness, deflection and stresses.

  2. Servo Reduces Friction In Flexure Bearing

    Science.gov (United States)

    Clingman, W. Dean

    1991-01-01

    Proposed servocontrol device reduces such resistive torques as stiction, friction, ripple, and cogging in flexure bearing described in LAR-14348, "Flexure Bearing Reduces Startup Friction". Reduces frictional "bump" torque encountered when bearing ball runs into buildup of grease on bearing race. Also used as cable follower to reduce torque caused by cable and hoses when they bend because of motion of bearing. New device includes torquer across ball race. Torquer controlled by servo striving to keep flexure at null, removing torque to outer ring. In effect, device is inner control loop reducing friction, but does not control platforms or any outer-control-loop functions.

  3. The architecture and associated fauna of Perouvianella peruviana, an endemic larger benthic foraminifera from the Cenomanian–Turonian transition interval of central Peru

    DEFF Research Database (Denmark)

    Consorti, Lorenzo; Navarro-Ramirez, Juan Pablo; Bodin, Stéphane

    2018-01-01

    -strategist foraminifera coexisted with P. peruviana. Moreover, a first description of the soritid taxa Pseudopeneroplis oyonensis n. gen., n. sp. is provided. Interestingly,the superposition of local and global environmental patterns onto the Western Peruvian shelf water masses triggered a mass development...... that were not affected by environmental conditions related to the Cenomanian–Turonian transition. A new architectural analysis of P. peruviana tests found in abundance in central Peru has permitted a detailed update on its systematic and functional morphology. The paleoenvironment associated with the P...

  4. Identification of Bearing Failure Using Signal Vibrations

    Science.gov (United States)

    Yani, Irsyadi; Resti, Yulia; Burlian, Firmansyah

    2018-04-01

    Vibration analysis can be used to identify damage to mechanical systems such as journal bearings. Identification of failure can be done by observing the resulting vibration spectrum by measuring the vibration signal occurring in a mechanical system Bearing is one of the engine elements commonly used in mechanical systems. The main purpose of this research is to monitor the bearing condition and to identify bearing failure on a mechanical system by observing the resulting vibration. Data collection techniques based on recordings of sound caused by the vibration of the mechanical system were used in this study, then created a database system based bearing failure due to vibration signal recording sounds on a mechanical system The next step is to group the bearing damage by type based on the databases obtained. The results show the percentage of success in identifying bearing damage is 98 %.

  5. A prototype construction of bearing heater system

    International Nuclear Information System (INIS)

    Firman Silitonga

    2007-01-01

    A bearing heater system has been successfully constructed using transformer-like method of 1000 VA power, 220 V primary voltage, and 50 Hz electrical frequency. The bearing heater consists of primary coil 230 turns, U type and bar-type iron core with 36 cm 2 , 9 cm 2 ,and 3 cm 2 cross-section, and electrical isolation. The bearing heater is used to enlarge the diameter of the bearing so that it can be easily fixed on an electric motor shaft during replacement because the heating is conducted by treated the bearing as a secondary coil of a transformer. This bearing heater can be used for bearing with 3 and 6 cm of inner diameter and 12 cm of maximum outside diameter. (author)

  6. Noise of oil lubricated journal bearings

    International Nuclear Information System (INIS)

    Rho, Byoung Hoo; Kim, Kyung Woong

    2002-01-01

    The purpose of the paper is to provide a procedure to calculate the noise of oil lubricated journal bearings. To do this, the nonlinear transient analysis of rotor-bearing system including rotor imbalance is performed. Acoustical properties of the bearing are investigated through frequency analysis of the pressure fluctuation of the fluid film calculated from the nonlinear analysis. Furthermore, a transmission theory of plane waves on a boundary of the outer surface of the bearing is used to obtain the sound pressure level of the bearing. Results show that the sound pressure level of the bearing can be increased with the rotational speed of the rotor although the whirl amplitude of the rotor is decreased at high speed. Noise estimating procedures presented in this paper could be an aid in the evaluation and understanding of acoustical properties of oil lubricated journal bearings

  7. Genomic evidence of geographically widespread effect of gene flow from polar bears into brown bears.

    Science.gov (United States)

    Cahill, James A; Stirling, Ian; Kistler, Logan; Salamzade, Rauf; Ersmark, Erik; Fulton, Tara L; Stiller, Mathias; Green, Richard E; Shapiro, Beth

    2015-03-01

    Polar bears are an arctic, marine adapted species that is closely related to brown bears. Genome analyses have shown that polar bears are distinct and genetically homogeneous in comparison to brown bears. However, these analyses have also revealed a remarkable episode of polar bear gene flow into the population of brown bears that colonized the Admiralty, Baranof and Chichagof islands (ABC islands) of Alaska. Here, we present an analysis of data from a large panel of polar bear and brown bear genomes that includes brown bears from the ABC islands, the Alaskan mainland and Europe. Our results provide clear evidence that gene flow between the two species had a geographically wide impact, with polar bear DNA found within the genomes of brown bears living both on the ABC islands and in the Alaskan mainland. Intriguingly, while brown bear genomes contain up to 8.8% polar bear ancestry, polar bear genomes appear to be devoid of brown bear ancestry, suggesting the presence of a barrier to gene flow in that direction. © 2014 The Authors. Molecular Ecology Published by John Wiley & Sons Ltd.

  8. Development and Evaluation of Titanium Spacesuit Bearings

    Science.gov (United States)

    Rhodes, Richard; Battisti, Brian; Ytuarte, Raymond, Jr.; Schultz, Bradley

    2016-01-01

    The Z-2 Prototype Planetary Extravehicular Space Suit Assembly is a continuation of NASA's Z-series of spacesuits, designed with the intent of meeting a wide variety of exploration mission objectives, including human exploration of the Martian surface. Incorporating titanium bearings into the Z-series space suit architecture allows us to reduce mass by an estimated 23 lbs per suit system compared to the previously used stainless steel bearing race designs, without compromising suit functionality. There are two obstacles to overcome when using titanium for a bearing race- 1) titanium is flammable when exposed to the oxygen wetted environment inside the space suit and 2) titanium's poor wear properties are often challenging to overcome in tribology applications. In order to evaluate the ignitability of a titanium space suit bearing, a series of tests were conducted at White Sands Test Facility (WSTF) that introduced the bearings to an extreme test profile, with multiple failures imbedded into the test bearings. The testing showed no signs of ignition in the most extreme test cases; however, substantial wear of the bearing races was observed. In order to design a bearing that can last an entire exploration mission (approx. 3 years), design parameters for maximum contact stress need to be identified. To identify these design parameters, bearing test rigs were developed that allow for the quick evaluation of various bearing ball loads, ball diameters, lubricants, and surface treatments. This test data will allow designers to minimize the titanium bearing mass for a specific material and lubricant combination and design around a cycle life requirement for an exploration mission. This paper reviews the current research and testing that has been performed on titanium bearing races to evaluate the use of such materials in an enriched oxygen environment and to optimize the bearing assembly mass and tribological properties to accommodate for the high bearing cycle life for an

  9. Conditioning of alpha bearing wastes

    International Nuclear Information System (INIS)

    1991-01-01

    Alpha bearing wastes are generated during the reprocessing of spent fuel, mixed oxide fuel fabrication, decommissioning and other activities. The safe and effective management of these wastes is of particular importance owing to the radiotoxicity and long lived characteristics of certain transuranic (TRU) elements. The management of alpha bearing wastes involves a number of stages which include collection, characterization, segregation, treatment, conditioning, transport, storage and disposal. This report describes the currently available matrices and technologies for the conditioning of alpha wastes and relates them to their compatibility with the other stages of the waste management process. The selection of a specific immobilization process is dependent on the waste treatment state and the subsequent handling, transport, storage and disposal requirements. The overall objectives of immobilization are similar for all waste producers and processors, which are to produce: (a) Waste forms with sufficient mechanical, physical and chemical stability to satisfy all stages of handling, transport and storage (referred to as the short term requirements), and (b) Waste forms which will satisfy disposal requirements and inhibit the release of radionuclides to the biosphere (referred to as the long term requirements). Cement and bitumen processes have already been successfully applied to alpha waste conditioning on the industrial scale in many of the IAEA Member States. Cement systems based on BFS and pozzolanic cements have emerged as the principal encapsulation matrices for the full range of alpha bearing wastes. Alternative technologies, such as polymers and ceramics, are being developed for specific waste streams but are unlikely to meet widespread application owing to cost and process complexity. The merits of alpha waste conditioning are improved performance in transport, storage and disposal combined with enhanced public perception of waste management operations. These

  10. Comparison of Alignment Correction Angles Between Fixed-Bearing and Mobile-Bearing UKA.

    Science.gov (United States)

    Inoue, Atsuo; Arai, Yuji; Nakagawa, Shuji; Inoue, Hiroaki; Yamazoe, Shoichi; Kubo, Toshikazu

    2016-01-01

    Good outcomes have been reported with both fixed-bearing and mobile-bearing unicompartmental knee arthroplasty (UKA). However, overcorrected alignment could induce the progression of arthritis on the non-arthroplasty side. Changes of limb alignment after UKA with both types of bearings (fixed bearing: 24 knees, mobile bearing: 28 knees) were investigated. The mean difference between the preoperative standing femoral-tibial angle (FTA) and postoperative standing FTA was significantly larger in mobile bearing UKA group. In fixed-bearing UKA, there must be some laxity in MCL tension so that a 2-mm tension gauge can be inserted. In mobile-bearing UKA, appropriate MCL tension is needed to prevent bearing dislocation. This difference in MCL tension may have caused the difference in the correction angle between the groups. Copyright © 2016 Elsevier Inc. All rights reserved.

  11. Seismic isolation rubber bearings for nuclear facilities

    International Nuclear Information System (INIS)

    Fujita, Takafumi

    1991-01-01

    This paper describes results of biaxial breaking tests by compression and shear and by tension and shear for seismic isolation rubber bearings with bolted-type connections. The bearings used in the tests were low-damping rubber bearings, high-damping rubber bearings, and lead-rubber bearings. Three modes of failure of the bolted-type bearings were observed in the tests. They are the breaking failure by tension and shear; the breaking failure by compression and shear; and the buckling failure by compression and shear. The first and the second modes of failures are almost independent of the types and the sizes of the bearings. The breaking conditions of those failure modes are described in the axial-stress-shear-strain plane. This expression is useful for the evaluation of safety margins of the bearings. The paper outlines the basic design of the nuclear-grade bearings which were used for large-scale rubber bearing tests in a research project for seismic isolation of FBR plants. It also discusses the protection method against aging and the quality control which are important for implementation. (orig./HP)

  12. Seismic isolation rubber bearings for nuclear facilities

    International Nuclear Information System (INIS)

    Fujita, Takafumi

    1989-01-01

    This paper describes results of biaxial breaking tests by compression and shear and by tension and shear for seismic isolation rubber bearings with bolted-type connections. The bearings used in the tests were low-damping rubber bearings, high-damping rubber bearings, and lead-rubber bearings. Three modes of failure of the bolted-type bearings were observed in the tests. They are the breaking failure by tension and shear; the breaking failure by compression and shear; and the buckling failure by compression and shear. The first and the second modes of failures are almost independent of the types and the sizes of the bearings. The breaking conditions of those failure modes are described in the axial stress-shear strain plane. This expression is useful for the evaluation of safety margins of the bearings. The paper outlines the basic design of the nuclear-grade bearings which were used for large-scale rubber bearing tests in a research project for seismic isolation of fast breeder reactor (FBR) plants. The paper also discusses the protection method against aging and the quality control which are important for implementation

  13. The functional significance of the spinose keel structure of benthic foraminifera: inferences from Miliolina cristata Millett, 1898 (Miliolida) from northeast Romania

    Science.gov (United States)

    Dumitriţa Dumitriu, Simina; Dubicka, Zofia; Ionesi, Viorel

    2018-01-01

    The paper presents Miocene (lower Sarmatian) benthic foraminifera from the FH3P1 Rădăuţi Core section from the northwestern part of the Moldavian Platform, Romania. Based on foraminiferal assemblages we infer sediments were deposited in shallow-water, including marine-marginal environments, of varying salinities from brackish to normal marine with some short and rather small sea-level changes. Moreover, we describe for the first time in the Moldavian Platform a very rare species, Miliolina cristata Millett, which presents a characteristic spinose keel. Based on a detailed study of the test morphology and its variability, observed in picked material as well as in thin sections, we discuss some palaeoecological aspects of these foraminifera. M. cristata probably does not constitute a distinctive species, but it is more probable that some miliolid taxa developed such an exoskeletal feature in response to new environmental conditions, such as more turbulent water. Accordingly, our study would support the thesis that one of the functions of the benthic foraminiferal spines is to stabilize foraminiferal tests found in sandy substrates from high-energy environments.

  14. Attempt of absolute dating and reconstitutions of climate changes in the Caribbean Sea: multi-proxy approaches to planktonic foraminifera and fine aragonitic fraction

    International Nuclear Information System (INIS)

    Sepulcre, S.

    2008-06-01

    Absolute dating of climate archives is essential to better understand climate mechanisms. A marine sediment core from the Caribbean Sea enriched in fine-grained aragonite (suitable to U/Th dating) has been studied for both planktonic foraminifera tests (≥150 μm) and fine fraction (≤63 μm) over the last one million years using mineralogical and geochemical approaches. This study aims at i) examining lead/lag of δ 18 O and radiometric ages of the different-size fractions and ii) reconstructing paleo-environment in the area. The fine fraction mineralogy is strongly influenced by glacial-interglacial sea level changes. The offset of δ 18 O and 14 C ages between the fine and foraminifera fractions during Termination I is partly explained by a bioturbation model. Attempt of U/Th dating to Termination II and V reveals that the fine fraction contains non-radiogenic Th, which needs further analytical development. Reconstructed surface water δ 18 O changes suggest a decrease in surface water salinity at the end of Mid-Pleistocene Transition related to ITCZ position over the Caribbean Sea. (author)

  15. A review of bear farming and bear trade in Lao People's Democratic Republic

    Directory of Open Access Journals (Sweden)

    E. Livingstone

    2018-01-01

    Full Text Available This study reviews the bear farming industry in Lao PDR with the objective of documenting the current number of commercial bear facilities (i.e. captive bear facilities judged to be trading in bear bile and/or bears and bear parts and the number of bears contained within these facilities, noting changes since it was last examined between 2000 and 2012 by Livingstone and Shepherd (2014. We surveyed all known commercial bear facilities and searched for previously unrecorded facilities. We compared our records with Livingstone and Shepherd (2014 and corrected some duplicate records from their study. In 2017, we recorded seven commercial facilities; four dedicated bear farms, and three tiger farms that were reportedly also keeping bears. We found that between 2012 and 2017 the recorded number of dedicated bear farms reduced by two, and the recorded number of tiger farms also keeping bears increased by one. Within the same period, the total number of captive bears among all facilities in Lao PDR hardly changed (+one, but the number of bears within each facility did. The northern facilities, owned by ethnic Chinese, have expanded since 2012, and central and southern facilities have downsized or closed. While bear farming appears to be downsizing in Lao PDR overall, efforts to phase it out are undermined by the expansion of foreign owned facilities in the north, within Special and Specific Economic Zones that largely cater to a Chinese market, and where the Lao government's efforts to enforce laws and protect wildlife appear to be lacking. Closing the facilities in the north will require political will and decisive law enforcement. Keywords: Bear farms, Bear bile, Gall bladder, Urso-deoxycholic acid, Bear bile extraction facilities, Lao PDR, Ursus thibetanus

  16. Benthic foraminifera and bottom water evolution in the middle-southern Okinawa Trough during the last 18 ka

    Institute of Scientific and Technical Information of China (English)

    LI Tiegang; XIANG Rong; SUN Rongtao; CAO Qiyuan

    2005-01-01

    A piston sediment core E017 from the middle-southern Okinawa Trough was investigated. A preliminary study of the deep-water evolution since 18 cal. ka BP was performed based on the quantitative census data of benthic foraminiferal fauna, together with planktonic foraminiferal oxygen and carbon isotope, AMS14C dating, and the previous results achieved in the southern Okinawa Trough. The result shows that the benthic fauna was dominated by Bulimina aculeata (d'Orbigny), Uvigerina peregrina (Cushman), Hispid Uvigerina and Uvigerina dirupta (Todd) during the glaciation-deglaciation before 9.2 cal. ka BP, while Epistominella exigua (Brady), Pullenia bulloides (d'Orbigny), Cibicidoides hyalina (Hofker), Sphaeroidina bulloides (d'Orbigny) and Globocassidulina subglobosa (Brady) predominated the fauna in the post-glacial period after 9.2 cal. ka BP. The benthic foraminifera accumulation rate (BFAR), paleoproductivity estimates and benthic foraminiferal assemblage conformably indicate that surface water paleoproductivity and organic matter flux during the glaciation-deglaciation were higher than those of the post-glacial period in the middle-southern Okinawa Trough, and gradually enhanced from the southern to the central Okinawa Trough during the glaciation-deglaciation, which could be caused by the discrepancy of the terrigenous nutrients supply. High abundances of E. exigua, an indicator of pulsed organic matter input, after 9.2 cal. ka BP may indicate that the intensity of seasonally riverine pulsed flux during the post-glacial period was stronger than that of the glaciation-deglaciation period, and the seasonal influx in the central trough might be stronger than in the south. The temporal distributions of the typical species indicating bottom water oxygen content and ventilation condition show that the ventilation of the bottom water during the post-glacial period is more active than the glaciation-deglaciation, which reflects that the evolution of the intermediate and

  17. New insights to ecology, ontogeny and teratology of Larger Benthic Foraminifera by biometrics based on microCT.

    Science.gov (United States)

    Briguglio, A.; Fabienke, W.; Wolfgring, E.; Ferrández Cañadell, C.; Hohenegger, J.

    2012-04-01

    The main function of tests in Larger Benthic Foraminifera (LBF) is to provide their endosymbiotic algae with enough light to obtain net photosynthetic rates and to create sufficient accommodation space. To study the relation between these two factors and to understand how the cell reacts to growth and to the environment, the newly developed technique of X-ray micro-Computer-Tomography (microCT) allows measurement of all characters of complex tests without destruction. Growth studies on 48 specimens of living and fossil species have been performed. The volumes of the lumina have been calculated as well as further 2-dimensional parameters related to volumes as chamber height, chamber width and septal distance. The volumes of chamber lumina represent cell growth in their sequence, thus demonstrating interruptions, increase/decrease or oscillations in growth rates caused by external factors affecting growth during life time (e.g. seasons). Correlations between volumes and the one-dimensional parameters have been calculated to check the form of relationship. According to our results, some parameters seem to oscillate exactly as the volume (therefore accommodating it), while others seem to oscillate constantly around a given growth function. Concerning the palaeobiology, beside the study of specimens with 'normal' growth, thus not drastically affected by external factors, some interesting morphologies have been investigated. Pluriembryonal apparati as well as secondary equatorial layers have been segmented, extracted and quantified in almost 15 specimens of Cycloclypeus carpenteri, 8 twin specimens of nummulitids tests have been also investigated to show where and how the fusion starts and volumetric quantifications of each single spiral in multispiral grown test of some large Eocene Nummulitids has also been calculated to show in which way and when (ontogenetically) a new spiral starts. The combination of all measurements allows interpretation of different biological

  18. Dinoflagellate cysts and benthic foraminifera in surface sediments from the Mar Piccolo in Taranto (Ionian Sea, Southern Italy)

    Science.gov (United States)

    Ferraro, L.; Rubino, F.; Frontalini, F.; Belmonte, M.; Di Leo, A.; Giandomenico, S.; Greco, M.; Lirer, F.; Spada, L.; Vallefuoco, M.

    2012-12-01

    Coastal areas have traditionally been places of human settlement, with the increasing development of cities, industries and other human-related activities possibly having an impact on the aquatic ecosystem. These impacts may take the form of pollution from industrial, domestic, agricultural or mining activities. For this reason, attention to marine environmental problems has recently increased and the search for new methodologies and techniques for the monitoring of coastal-marine areas become more and more active and accurate. In this context biological indicators result a useful tool to provide indication of environmental conditions including the presence or absence of contaminants; in fact biological monitoring is more directly related to the ecological health of an ecosystem than are chemical data. The increasing importance of bioindicators is also encouraged within the European Union's Water Framework Directive (WFD), which aims to achieve a good ecological status in all European water bodies (i.e., rivers, lakes and coastal waters). Among the wide range of bioindicators, 5 biological elements are listed within the WFD: phytoplankton, macroalgae, angiosperms, benthic invertebrates and fishes. Benthic invertebrates as foraminifera represent a group of protozoa widely distributed in all brackish and marine environments which are used in studies assessing the environmental quality of areas subject to intense human activity. Moreover in coastal marine environments benthic and pelagic domain present several relationships, one of these is represented by the life cycles of phytoplankton species, as Dinoflagellates, which include the production of benthic stages (cysts). These dormant stages, which accumulate in confined marine muddy areas, such as ports, lagoons or estuaries, can reach high densities, similar to the seed banks of terrestrial plants. The cysts have a high preservation potential and can rest in/on the sediments for decades. Due to this peculiar

  19. Electron beam melting of bearing materials

    Energy Technology Data Exchange (ETDEWEB)

    Goldschmied, G.; Schuler, A. (Technische Univ., Vienna (Austria). Inst. fuer Allgemeine Elektrotechnik); Elsinger, G.; Koroschetz, F. (MIBA Gleitlager AG, Laakirchen (Austria)); Tschegg, E.K. (Technische Univ., Vienna (Austria). Inst. fuer Angewandte und Technische Physik)

    1990-06-01

    This paper reports on a surface treatment method for the bearing materials AlSn6 which permits the use of this material without the overlay usually required. Microstructural refinement is achieved by means of a surface melting technique using an electron beam with successive rapid solidification. Extremely fine tin precipitates are formed in the melted surface layer which lead to significantly better tribological properties of the bearing material. Tests compared the tribological properties for AlSn6 bearings treated by the surface melting technique with those of untreated bearings. Whereas all untreated bearings failed by seizure after only 2 h of testing, 30% of the tested bearings which had been surface melted survived the entire testing program without damage.

  20. Bearing Health Assessment Based on Chaotic Characteristics

    Directory of Open Access Journals (Sweden)

    Chen Lu

    2013-01-01

    Full Text Available Vibration signals extracted from rotating parts of machinery carry a lot of useful information about the condition of operating machine. Due to the strong non-linear, complex and non-stationary characteristics of vibration signals from working bearings, an accurate and reliable health assessment method for bearing is necessary. This paper proposes to utilize the selected chaotic characteristics of vibration signal for health assessment of a bearing by using self-organizing map (SOM. Both Grassberger-Procaccia algorithm and Takens' theory are employed to calculate the characteristic vector which includes three chaotic characteristics, such as correlation dimension, largest Lyapunov exponent and Kolmogorov entropy. After that, SOM is used to map the three corresponding characteristics into a confidence value (CV which represents the health state of the bearing. Finally, a case study based on vibration datasets of a group of testing bearings was conducted to demonstrate that the proposed method can reliably assess the health state of bearing.

  1. Trends in Controllable Oil Film Bearings

    DEFF Research Database (Denmark)

    Santos, Ilmar

    2011-01-01

    This work gives an overview about the theoretical and experimental achievements of mechatronics applied to oil film bearings, with the aim of: controlling the lateral vibration of flexible rotating shafts; modifying bearing dynamic characteristics, as stiffness and damping properties; increasing......" components and be applied to rotating machines with the goal of avoiding unexpected stops of plants, performing rotordynamic tests and identifying model parameters "on site". Emphasis is given to the controllable lubrication (active lubrication) applied to different types of oil film bearings, i...

  2. Use of the Boron partition coefficient ‘KD’ and B/Ca from planktonic foraminifera in the estimation of past seawater pCO2

    Digital Repository Service at National Institute of Oceanography (India)

    Naik, S.S.; Naidu, P.D.

    We assess the usefulness of the empirical boron partition coefficient, KD and B/Ca measured from planktonic foraminifera in estimation of pCO2 using three different relationships between KD and temperature derived...

  3. Technical Development Path for Gas Foil Bearings

    Science.gov (United States)

    Dellacorte, Christopher

    2016-01-01

    Foil gas bearings are in widespread commercial use in air cycle machines, turbocompressors and microturbine generators and are emerging in more challenging applications such as turbochargers, auxiliary power units and propulsion gas turbines. Though not well known, foil bearing technology is well over fifty years old. Recent technological developments indicate that their full potential has yet to be realized. This paper investigates the key technological developments that have characterized foil bearing advances. It is expected that a better understanding of foil gas bearing development path will aid in future development and progress towards more advanced applications.

  4. Gearbox Reliability Collaborative Bearing Calibration

    Energy Technology Data Exchange (ETDEWEB)

    van Dam, J.

    2011-10-01

    NREL has initiated the Gearbox Reliability Collaborative (GRC) to investigate the root cause of the low wind turbine gearbox reliability. The GRC follows a multi-pronged approach based on a collaborative of manufacturers, owners, researchers and consultants. The project combines analysis, field testing, dynamometer testing, condition monitoring, and the development and population of a gearbox failure database. At the core of the project are two 750kW gearboxes that have been redesigned and rebuilt so that they are representative of the multi-megawatt gearbox topology currently used in the industry. These gearboxes are heavily instrumented and are tested in the field and on the dynamometer. This report discusses the bearing calibrations of the gearboxes.

  5. Nuclear genomic sequences reveal that polar bears are an old and distinct bear lineage.

    Science.gov (United States)

    Hailer, Frank; Kutschera, Verena E; Hallström, Björn M; Klassert, Denise; Fain, Steven R; Leonard, Jennifer A; Arnason, Ulfur; Janke, Axel

    2012-04-20

    Recent studies have shown that the polar bear matriline (mitochondrial DNA) evolved from a brown bear lineage since the late Pleistocene, potentially indicating rapid speciation and adaption to arctic conditions. Here, we present a high-resolution data set from multiple independent loci across the nuclear genomes of a broad sample of polar, brown, and black bears. Bayesian coalescent analyses place polar bears outside the brown bear clade and date the divergence much earlier, in the middle Pleistocene, about 600 (338 to 934) thousand years ago. This provides more time for polar bear evolution and confirms previous suggestions that polar bears carry introgressed brown bear mitochondrial DNA due to past hybridization. Our results highlight that multilocus genomic analyses are crucial for an accurate understanding of evolutionary history.

  6. Treatment of alpha bearing wastes

    International Nuclear Information System (INIS)

    1988-01-01

    This report deals with the current state of the art of alpha waste treatment, which is an integral part of the overall nuclear waste management system. The International Atomic Energy Agency (IAEA) defines alpha bearing waste as 'waste containing one or more alpha emitting radionuclides, usually actinides, in quantities above acceptable limits'. The limits are established by national regulatory bodies. The limits above which wastes are considered as alpha contaminated refer to the concentrations of alpha emitters that need special consideration for occupational exposures and/or potential safety, health, or environmental impact during one or more steps from generation through disposal. Owing to the widespread use of waste segregation by source - that is, based upon the 'suspect origin' of the material - significant volumes of waste are being handled as alpha contaminated which, in fact, do not require such consideration by reason of risk or environmental concern. The quantification of de minimis concepts by national regulatory bodies could largely contribute to the safe reduction of waste volumes and associated costs. Other factors which could significantly contribute to the reduction of alpha waste arisings are an increased application of assaying and sorting, instrumentation and the use of feedback mechanisms to control or modify the processes which generate these wastes. Alpha bearing wastes are generated during fabrication and reprocessing of nuclear fuels, decommissioning of alpha contaminated facilities, and other activities. Most alpha wastes are contact handled, but a small portion may require shielding or remote handling because of high levels of neutron (n), beta (β), or gamma (γ) emissions associated with the waste material. This report describes the sources and characteristics of alpha wastes and strategies for alpha waste management. General descriptions of treatment processes for solid and liquid alpha wastes are included. 71 refs, 14 figs, 9 tabs

  7. Evaluation of bearing configurations using the single bearing tester in liquid nitrogen

    Science.gov (United States)

    Jett, T.; Hall, P.; Thom, R.

    1991-01-01

    Various bearing configurations were tested using the Marshall Space Flight Center single bearing tester with LN2 as the cryogenic coolant. The baseline was one Rocketdyne phase one high pressure oxidizer turbopump (HPOTP) pump end 45-mm bore bearing. The bearing configurations that were tested included a Salox/M cage configuration, a silicon nitride ball configuration, an elongated cage configuration, and a Bray 601 grease configuration.

  8. Rolling Bearing Life Prediction, Theory, and Application

    Science.gov (United States)

    Zaretsky, Erwin V.

    2016-01-01

    A tutorial is presented outlining the evolution, theory, and application of rolling-element bearing life prediction from that of A. Palmgren, 1924; W. Weibull, 1939; G. Lundberg and A. Palmgren, 1947 and 1952; E. Ioannides and T. Harris, 1985; and E. Zaretsky, 1987. Comparisons are made between these life models. The Ioannides-Harris model without a fatigue limit is identical to the Lundberg-Palmgren model. The Weibull model is similar to that of Zaretsky if the exponents are chosen to be identical. Both the load-life and Hertz stress-life relations of Weibull, Lundberg and Palmgren, and Ioannides and Harris reflect a strong dependence on the Weibull slope. The Zaretsky model decouples the dependence of the critical shear stress-life relation from the Weibull slope. This results in a nominal variation of the Hertz stress-life exponent. For 9th- and 8th-power Hertz stress-life exponents for ball and roller bearings, respectively, the Lundberg-Palmgren model best predicts life. However, for 12th- and 10th-power relations reflected by modern bearing steels, the Zaretsky model based on the Weibull equation is superior. Under the range of stresses examined, the use of a fatigue limit would suggest that (for most operating conditions under which a rolling-element bearing will operate) the bearing will not fail from classical rolling-element fatigue. Realistically, this is not the case. The use of a fatigue limit will significantly overpredict life over a range of normal operating Hertz stresses. (The use of ISO 281:2007 with a fatigue limit in these calculations would result in a bearing life approaching infinity.) Since the predicted lives of rolling-element bearings are high, the problem can become one of undersizing a bearing for a particular application. Rules had been developed to distinguish and compare predicted lives with those actually obtained. Based upon field and test results of 51 ball and roller bearing sets, 98 percent of these bearing sets had acceptable

  9. Unbalance Response Prediction for Rotors on Ball Bearings Using Speed and Load Dependent Nonlinear Bearing Stiffness

    Science.gov (United States)

    Fleming, David P.; Poplawski, J. V.

    2003-01-01

    Rolling-element bearing forces vary nonlinearly with bearing deflection. Thus an accurate rotordynamic analysis requires that bearing forces corresponding to the actual bearing deflection be utilized. For this work bearing forces were calculated by COBRA-AHS, a recently developed rolling-element bearing analysis code. Bearing stiffness was found to be a strong function of bearing deflection, with higher deflection producing markedly higher stiffness. Curves fitted to the bearing data for a range of speeds and loads were supplied to a flexible rotor unbalance response analysis. The rotordynamic analysis showed that vibration response varied nonlinearly with the amount of rotor imbalance. Moreover, the increase in stiffness as critical speeds were approached caused a large increase in rotor and bearing vibration amplitude over part of the speed range compared to the case of constant bearing stiffness. Regions of bistable operation were possible, in which the amplitude at a given speed was much larger during rotor acceleration than during deceleration. A moderate amount of damping will eliminate the bistable region, but this damping is not inherent in ball bearings.

  10. Phylogeography of mitochondrial DNA variation in brown bears and polar bears

    Science.gov (United States)

    Shields, Gerald F.; Adams, Deborah; Garner, Gerald W.; Labelle, Martine; Pietsch, Jacy; Ramsay, Malcolm; Schwartz, Charles; Titus, Kimberly; Williamson, Scott

    2000-01-01

    We analyzed 286 nucleotides of the middle portion of the mitochondrial cytochrome b gene of 61 brown bears from three locations in Alaska and 55 polar bears from Arctic Canada and Arctic Siberia to test our earlier observations of paraphyly between polar bears and brown bears as well as to test the extreme uniqueness of mitochondrial DNA types of brown bears on Admiralty, Baranof, and Chichagof (ABC) islands of southeastern Alaska. We also investigated the phylogeography of brown bears of Alaska's Kenai Peninsula in relation to other Alaskan brown bears because the former are being threatened by increased human development. We predicted that: (1) mtDNA paraphyly between brown bears and polar bears would be upheld, (2) the mtDNA uniqueness of brown bears of the ABC islands would be upheld, and (3) brown bears of the Kenai Peninsula would belong to either clade II or clade III of brown bears of our earlier studies of mtDNA. All of our predictions were upheld through the analysis of these additional samples.

  11. Phylogeography of mitochondrial DNA variation in brown bears and polar bears.

    Science.gov (United States)

    Shields, G F; Adams, D; Garner, G; Labelle, M; Pietsch, J; Ramsay, M; Schwartz, C; Titus, K; Williamson, S

    2000-05-01

    We analyzed 286 nucleotides of the middle portion of the mitochondrial cytochrome b gene of 61 brown bears from three locations in Alaska and 55 polar bears from Arctic Canada and Arctic Siberia to test our earlier observations of paraphyly between polar bears and brown bears as well as to test the extreme uniqueness of mitochondrial DNA types of brown bears on Admiralty, Baranof, and Chichagof (ABC) islands of southeastern Alaska. We also investigated the phylogeography of brown bears of Alaska's Kenai Peninsula in relation to other Alaskan brown bears because the former are being threatened by increased human development. We predicted that: (1) mtDNA paraphyly between brown bears and polar bears would be upheld, (2) the mtDNA uniqueness of brown bears of the ABC islands would be upheld, and (3) brown bears of the Kenai Peninsula would belong to either clade II or clade III of brown bears of our earlier studies of mtDNA. All of our predictions were upheld through the analysis of these additional samples. Copyright 2000 Academic Press.

  12. State Space Formulation of Nonlinear Vibration Responses Collected from a Dynamic Rotor-Bearing System: An Extension of Bearing Diagnostics to Bearing Prognostics.

    Science.gov (United States)

    Tse, Peter W; Wang, Dong

    2017-02-14

    Bearings are widely used in various industries to support rotating shafts. Their failures accelerate failures of other adjacent components and may cause unexpected machine breakdowns. In recent years, nonlinear vibration responses collected from a dynamic rotor-bearing system have been widely analyzed for bearing diagnostics. Numerous methods have been proposed to identify different bearing faults. However, these methods are unable to predict the future health conditions of bearings. To extend bearing diagnostics to bearing prognostics, this paper reports the design of a state space formulation of nonlinear vibration responses collected from a dynamic rotor-bearing system in order to intelligently predict bearing remaining useful life (RUL). Firstly, analyses of nonlinear vibration responses were conducted to construct a bearing health indicator (BHI) so as to assess the current bearing health condition. Secondly, a state space model of the BHI was developed to mathematically track the health evolution of the BHI. Thirdly, unscented particle filtering was used to predict bearing RUL. Lastly, a new bearing acceleration life testing setup was designed to collect natural bearing degradation data, which were used to validate the effectiveness of the proposed bearing prognostic method. Results show that the prediction accuracy of the proposed bearing prognostic method is promising and the proposed bearing prognostic method is able to reflect future bearing health conditions.

  13. State Space Formulation of Nonlinear Vibration Responses Collected from a Dynamic Rotor-Bearing System: An Extension of Bearing Diagnostics to Bearing Prognostics

    Directory of Open Access Journals (Sweden)

    Peter W. Tse

    2017-02-01

    Full Text Available Bearings are widely used in various industries to support rotating shafts. Their failures accelerate failures of other adjacent components and may cause unexpected machine breakdowns. In recent years, nonlinear vibration responses collected from a dynamic rotor-bearing system have been widely analyzed for bearing diagnostics. Numerous methods have been proposed to identify different bearing faults. However, these methods are unable to predict the future health conditions of bearings. To extend bearing diagnostics to bearing prognostics, this paper reports the design of a state space formulation of nonlinear vibration responses collected from a dynamic rotor-bearing system in order to intelligently predict bearing remaining useful life (RUL. Firstly, analyses of nonlinear vibration responses were conducted to construct a bearing health indicator (BHI so as to assess the current bearing health condition. Secondly, a state space model of the BHI was developed to mathematically track the health evolution of the BHI. Thirdly, unscented particle filtering was used to predict bearing RUL. Lastly, a new bearing acceleration life testing setup was designed to collect natural bearing degradation data, which were used to validate the effectiveness of the proposed bearing prognostic method. Results show that the prediction accuracy of the proposed bearing prognostic method is promising and the proposed bearing prognostic method is able to reflect future bearing health conditions.

  14. Friction coefficients of PTFE bearing liner

    Science.gov (United States)

    Daniels, C. M.

    1979-01-01

    Data discusses frictional characteristics of PTFE (polytetrafluoroethylene) under temperature extremes and in vacuum environment. Tests were also run on reduced scale hardware to determine effects of vacuum. Data is used as reference by designers of aircraft-control system rod-end bearings and for bearings used in polar regions.

  15. Shaft Center Orbit in Dynamically Loaded Bearings

    DEFF Research Database (Denmark)

    Klit, Peder

    2005-01-01

    The aim of this work is to demonstrate how to utilize the bearings damping coe±cients to estimate the orbit for a dynamically loaded journal bearing. The classical method for this analysis was developed by Booker in 1965 [1]and described further in 1972 [2]. Several authors have re¯ned this metho...

  16. Can polar bear hairs absorb environmental energy?

    Directory of Open Access Journals (Sweden)

    He Ji-Huan

    2011-01-01

    Full Text Available A polar bear (Ursus maritimus has superior ability to survive in harsh Arctic regions, why does the animal have such an excellent thermal protection? The present paper finds that the unique labyrinth cavity structure of the polar bear hair plays an important role. The hair can not only prevent body temperature loss but can also absorb energy from the environment.

  17. 33 CFR 117.543 - Bear Creek.

    Science.gov (United States)

    2010-07-01

    ... 33 Navigation and Navigable Waters 1 2010-07-01 2010-07-01 false Bear Creek. 117.543 Section 117.543 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY BRIDGES DRAWBRIDGE OPERATION REGULATIONS Specific Requirements Maryland § 117.543 Bear Creek. (a) The draws of the Baltimore...

  18. Measurement of Wear in Radial Journal Bearings

    NARCIS (Netherlands)

    Ligterink, D.J.; Ligterink, D.J.; de Gee, A.W.J.

    1996-01-01

    this article, the measurement of wear in radial journal bearings is discussed, where a distinction is made between stationary and non-stationary contact conditions. Starting with Holm/Archard's wear law, equations are derived for the calculation of the specific wear rate k of the bearing material as

  19. Stabilizing gas bearing in free piston machines

    Science.gov (United States)

    Dhar, Manmohan (Inventor)

    1992-01-01

    In a free piston engine, to reduce dynamic loads on the reciprocating elements caused by a time varying pressure gradient across the gas bearing and close clearance seals provided therein, drain galleries are incorporated at the ends of the gas bearings to isolate the same, and circumferentially spaced grooves are incorporated in the close clearance seal region.

  20. Accuracy of Spindle Units with Hydrostatic Bearings

    Directory of Open Access Journals (Sweden)

    Fedorynenko Dmytro

    2016-06-01

    Full Text Available The work is devoted to the research of precision regularities in a spindle unit by the trajectory of the spindle installed on hydrostatic bearings. The mathematical model of trajectories spindle with lumped parameters that allows to define the position of the spindle with regard the simultaneous influence of design parameters, geometrical deviations ofform, temperature deformation bearing surfaces, the random nature of operational parameters and technical loads of hydrostatic bearings has been developed. Based on the results of numerical modeling the influence of shape errors of bearing surface of hydrostatic bearing on the statistical characteristics of the radius vector trajectories of the spindle by varying the values rotational speed of the spindle and oil pressure in front hydrostatic bearing has been developed. The obtained statistical regularities of precision spindle unit have been confirmed experimentally. It has been shown that an effective way to increase the precision of spindle units is to regulate the size of the gap in hydrostatic spindle bearings. The new design of an adjustable hydrostatic bearing, which can improve the accuracy of regulation size gap has been proposed.

  1. On the dynamics of ball bearings

    NARCIS (Netherlands)

    Wensing, J.A.

    1998-01-01

    This investigation on the dynamic behaviour of ball bearings was motivated by the demand for silent bearings in noise-sensitive applications, especially in the household appliance and automotive industry. The present investigations are intended to provide a clear understanding of the role of the

  2. Nonlinear Dynamic Response of Compliant Journal Bearings

    Directory of Open Access Journals (Sweden)

    Glavatskih S.

    2012-07-01

    Full Text Available This paper investigates the dynamic response of the compliant tilting pad journal bearings subjected to synchronous excitation. Bearing compliance is affected by the properties of pad liner and pad support geometry. Different unbalance eccentricities are considered. It is shown that bearing dynamic response is non-linear. Journal orbit complexity increases with pad compliance though the orbit amplitudes are marginally affected at low loads. At high loads, the journal is forced to operate outside the bearing clearance. The polymer liner reduces the maximum oil film pressure by a factor of 2 when compared to the white metal liner. The nonlinear dynamic response of compliant tilting pad journal bearings is thoroughly discussed.

  3. The dynamic state monitoring of bearings system

    Directory of Open Access Journals (Sweden)

    Marek Krynke

    2015-03-01

    Full Text Available The article discusses the methods of dynamic state monitoring of bearings system. A vibration signal contains important technical information about the machine condition and is currently the most frequently used in diagnostic bearings systems. One of the main ad-vantages of machine condition monitoring is identifying the cause of failure of the bearings and taking preventative measures, otherwise the operation of such a machine will lead to frequent replacement of the bearings. Monitoring changes in the course of the operation of machin-ery repair strategies allows keeping the conditioned state of dynamic failure conditioned preventive repairs and repairs after-failure time. In addition, the paper also presents the fundamental causes of bearing failure and identifies mechanisms related to the creation of any type of damage.

  4. Transient response of two lobe aerodynamic journal bearing

    Directory of Open Access Journals (Sweden)

    Saurabh Kumar Yadav

    2018-03-01

    Full Text Available The dynamic behavior of a rotor-dynamic system is greatly affected by the performance of aerodynamic bearing and the performance of bearing is characterized by the stiffness and damping coefficients. In the present work, stiffness and damping coefficients of bearing are computed and the performance of the bearing is greatly changed with the change in bearing air film profile. The effect of lobe offset factors on the transient performance of aerodynamic bearing is presented. Bifurcation and Poincare diagrams of two lobe journal bearing have been presented for different offset factors. A bearing designer can judge the bearing performance based on bifurcation diagrams.

  5. Geology and geomorphology of Bear Lake Valley and upper Bear River, Utah and Idaho

    Science.gov (United States)

    Reheis, M.C.; Laabs, B.J.C.; Kaufman, D.S.

    2009-01-01

    Bear Lake, on the Idaho-Utah border, lies in a fault-bounded valley through which the Bear River flows en route to the Great Salt Lake. Surficial deposits in the Bear Lake drainage basin provide a geologic context for interpretation of cores from Bear Lake deposits. In addition to groundwater discharge, Bear Lake received water and sediment from its own small drainage basin and sometimes from the Bear River and its glaciated headwaters. The lake basin interacts with the river in complex ways that are modulated by climatically induced lake-level changes, by the distribution of active Quaternary faults, and by the migration of the river across its fluvial fan north of the present lake. The upper Bear River flows northward for ???150 km from its headwaters in the northwestern Uinta Mountains, generally following the strike of regional Laramide and late Cenozoic structures. These structures likely also control the flow paths of groundwater that feeds Bear Lake, and groundwater-fed streams are the largest source of water when the lake is isolated from the Bear River. The present configuration of the Bear River with respect to Bear Lake Valley may not have been established until the late Pliocene. The absence of Uinta Range-derived quartzites in fluvial gravel on the crest of the Bear Lake Plateau east of Bear Lake suggests that the present headwaters were not part of the drainage basin in the late Tertiary. Newly mapped glacial deposits in the Bear River Range west of Bear Lake indicate several advances of valley glaciers that were probably coeval with glaciations in the Uinta Mountains. Much of the meltwater from these glaciers may have reached Bear Lake via groundwater pathways through infiltration in the karst terrain of the Bear River Range. At times during the Pleistocene, the Bear River flowed into Bear Lake and water level rose to the valley threshold at Nounan narrows. This threshold has been modified by aggradation, downcutting, and tectonics. Maximum lake

  6. EFFECT OF CLEARANCE THE BALL BEARINGS ON INCORRECT WORK OF THREE-SUPORT BEARING SHAFT

    OpenAIRE

    Jarosław KACZOR

    2014-01-01

    Durability deep groove ball bearings depends on factors (called attributes) design, technological and operational. Among the design features one of the most important is play in the bearings. Polish Norm shows five groups of looseness in the bearings, in which the play range from 0 to 105 microns. Manufacturers of rolling bearings they only play group, which has a bearing data, without giving the exact value of the slack. Aim of this study is to determine how it affects the play in the bea...

  7. Failure of GIMBAL bearing in directional GYRO

    International Nuclear Information System (INIS)

    Pervaiz, R.; Baig, N.A.; Shahid, M.; Ahmad, A.; Chohan, G.Y.

    2003-01-01

    This paper relates to the directional gyro of a sensing device used in indigenously developed surface-to-surface missile. The assembling of more than one thousand components in the form of several sub assemblies including hundreds of silver solders of this device was done in the hundred-thousands-class clean room according to assembly procedure. Whereas more than twenty bearings including gimbals bearings were assembled in the ten-thousands-class clean room after inspection/ testing them on beating testing system as per routine. The device was entered in testing and adjustment phase after successful completion of assembly work. The directional gyro qualified all the tests except the most critical one, the drift-rate. The drift-rate of outer gimbal was 60% more than permissible limit whereas drift-rate of inner gimbal was found O.K. It was diagnosed that at least one inner gimbal bearing out of two had some problem. The results were same after rebalancing of gimbals three times. The directional gyro was disassembled in clean room and the radial-thrust-bearing was recovered and flange bearing which are inner gimbal bearings. They were checked on bearing testing system and it was found that flange-bearing had more friction than permissible limit and hence rejected but radial thrust bearing were declared O.K. The gyro was reassembled with new O.K. flange bearing and the assembly work was completed in all respects. The sensing device qualified all the tests including the drift-rate. This case study is being presented to emphasize the importance of careful assembly of gyro in clean environment. (author)

  8. 49 CFR 230.102 - Tender plain bearing journal boxes.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Tender plain bearing journal boxes. 230.102... Locomotives and Tenders Running Gear § 230.102 Tender plain bearing journal boxes. Plain bearing journal boxes... expected to damage the bearing; or have a detrimental effect on the lubrication of the journal and bearing...

  9. Faunal and stable isotopic analyses of benthic foraminifera from the Southeast Seep on Kimki Ridge offshore southern California, USA

    Science.gov (United States)

    McGann, Mary; Conrad, James E.

    2018-01-01

    deep infaunal species of Globobulimina, the shallow infaunal species Uvigerina peregrina, the epifaunal species Cibicidoides wuellerstorfi, and the shallow infaunal but aragonite-shelled species Hoeglundina elegans. The δ13C values downcore among each benthic species indicates ongoing fluid seepage through at least the last 3800 cal yr B.P. at Southeast Seep. Besides the continual local seepage, evidence from δ13C values of planktic foraminifera in the seep core suggest two pulses of methane (at 3000 and 3700 cal yr B.P.) were released that were large enough to influence much of the water column. Paired benthic and planktic foraminiferal stable oxygen isotope records provide evidence that there were no paleoenvironmental changes such as increased bottom-water temperature or changes in oxygen isotopic composition of bottom and pore waters during this 3800-year record to induce the methane releases. Instead, Southeast Seep appears to be the result of local faulting providing pathways for fluid to flow to the seafloor at a fault stepover or transpressional bend in the regional strike-slip system.

  10. Genomic Evidence of Widespread Admixture from Polar Bears into Brown Bears during the Last Ice Age.

    Science.gov (United States)

    Cahill, James A; Heintzman, Peter D; Harris, Kelley; Teasdale, Matthew D; Kapp, Joshua; Soares, Andre E R; Stirling, Ian; Bradley, Daniel; Edwards, Ceiridwen J; Graim, Kiley; Kisleika, Aliaksandr A; Malev, Alexander V; Monaghan, Nigel; Green, Richard E; Shapiro, Beth

    2018-05-01

    Recent genomic analyses have provided substantial evidence for past periods of gene flow from polar bears (Ursus maritimus) into Alaskan brown bears (Ursus arctos), with some analyses suggesting a link between climate change and genomic introgression. However, because it has mainly been possible to sample bears from the present day, the timing, frequency, and evolutionary significance of this admixture remains unknown. Here, we analyze genomic DNA from three additional and geographically distinct brown bear populations, including two that lived temporally close to the peak of the last ice age. We find evidence of admixture in all three populations, suggesting that admixture between these species has been common in their recent evolutionary history. In addition, analyses of ten fossil bears from the now-extinct Irish population indicate that admixture peaked during the last ice age, whereas brown bear and polar bear ranges overlapped. Following this peak, the proportion of polar bear ancestry in Irish brown bears declined rapidly until their extinction. Our results support a model in which ice age climate change created geographically widespread conditions conducive to admixture between polar bears and brown bears, as is again occurring today. We postulate that this model will be informative for many admixing species pairs impacted by climate change. Our results highlight the power of paleogenomics to reveal patterns of evolutionary change that are otherwise masked in contemporary data.

  11. Bear-ly” learning: Limits of abstraction in black bear cognition

    Directory of Open Access Journals (Sweden)

    Jennifer Vonk

    2018-02-01

    Full Text Available We presented two American black bears (Ursus americanus with a serial list learning memory task, and one of the bears with a matching-to-sample task. After extended training, both bears demonstrated some success with the memory task but failed to generalize the overarching rule of the task to novel stimuli. Matching to sample proved even more difficult for our bear to learn. We conclude that, despite previous success in training bears to respond to natural categories, quantity discriminations, and other related tasks, that bears may possess a cognitive limitation with regards to learning abstract rules. Future tests using different procedures are necessary to determine whether this is a limit of bears’ cognitive capacities, or a limitation of the current tasks as presented. Future tests should present a larger number of varying stimuli. Ideally, bears of various species should be tested on these tasks to demonstrate species as well as individual differences.

  12. Boron isotope-based seasonal paleo-pH reconstruction for the Southeast Atlantic - A multispecies approach using habitat preference of planktonic foraminifera

    Science.gov (United States)

    Raitzsch, Markus; Bijma, Jelle; Benthien, Albert; Richter, Klaus-Uwe; Steinhoefel, Grit; Kučera, Michal

    2018-04-01

    The boron isotopic composition of planktonic foraminiferal shell calcite (δ11BCc) provides valuable information on the pH of ambient water at the time of calcification. Hence, δ11BCc of fossil surface-dwelling planktonic foraminifera can be used to reconstruct ancient aqueous pCO2 if information on a second carbonate system parameter, temperature and salinity is available. However, pH and pCO2 of surface waters may vary seasonally, largely due to changes in temperature, DIC, and alkalinity. As also the shell fluxes of planktonic foraminifera show species-specific seasonal patterns that are linked to intra-annual changes in temperature, it is obvious that δ11BCc of a certain species reflects the pH and thus pCO2 biased towards a specific time period within a year. This is important to consider for the interpretation of fossil δ11BCc records that may mirror seasonal pH signals. Here we present new Multi-Collector Inductively Coupled Mass Spectrometry (MC-ICPMS) δ11BCc coretop data for the planktonic foraminifera species Globigerina bulloides, Globigerinoides ruber, Trilobatus sacculifer and Orbulina universa and compare them with δ11Bborate derived from seasonally resolved carbonate system parameters. We show that the inferred season-adjusted δ11BCc /δ11Bborate relationships are similar to existing calibrations and can be combined with published δ11BCc field and culture data to augment paleo-pH calibrations. To test the applicability of these calibrations, we used a core drilled on the Walvis Ridge in the Southeast Atlantic spanning the last 330,000 years to reconstruct changes in surface-water pCO2. The reconstruction based on G. bulloides, which reflects the austral spring season, was shown to yield values that closely resemble the Vostok ice-core data indicating that surface-water pCO2 was close to equilibrium with the atmosphere during the cooler spring season. In contrast, pCO2 estimated from δ11BCc of O. universa, T. sacculifer and G. ruber that

  13. Bottom water production variability in the Ross Sea slope during the Late-Pleistocene-Holocene as revealed by benthic foraminifera and sediment geochemistry

    Science.gov (United States)

    Asioli, A.; Langone, L.; Tateo, F.; Giannossi, M. L.; Giglio, F.; Summa, V.; Piva, A.; Ridente, D.; Trincardi, F.

    2009-04-01

    The Antarctic area produces bottom waters that ventilate the vast majority of the deep basins in the rest of the world ocean. The rate of formation in the source area and the strength of these cold bottom waters affect their flow toward the equator and are key factors affecting the Global Thermohaline Circulation during modern and past climate conditions. We present the results of a multidisciplinary study carried out on a core collected in 2377m of water depth on the slope off the Drygalski Basin (Ross Sea), along the modern path of the bottom waters. The goal of this research is to detect a qualitative signal of possible changes in the rate of bottom water production during the Late Pleistocene-Holocene by integrating micropaleontological and geochemical proxies. The micropaleontological signal is represented by the quantitative and qualitative variations of the agglutinated benthic foraminifera assemblages, while the amount of TOC, nitrogen, δ13C, δ15N, biogenic silica, CaCO3 in the sediment, along with the bulk rock mineralogy, provide information on the paleoproductivity and allow reconstruction of changes in the paleocirculation. The chronology is supported by 14C AMS datings on organic matter. Although this study is still in progress, the results obtained allow the following observations: 1) the Holocene sequence includes a major turnover around 8-8.5 calib kyr BP, leading to reduced nutrient utilization, probably reflecting an increased nutrient supply induced by an enhanced Upper Circumpolar Deep Water upwelling; 2) within this general context, the total concentration of benthic foraminifera preserved in the fossil component records millennial scale cycles of variable amplitude after 8.5 calib kyr BP and to present time. This oscillatory trend is paralleled by other parameters, such as the magnetic susceptibility, the dry density, the sheet silicates and the δ15N; 3) minima in foraminifera concentration reflect relatively increased dissolution, weaker

  14. Vibration model of rolling element bearings in a rotor-bearing system for fault diagnosis

    Science.gov (United States)

    Cong, Feiyun; Chen, Jin; Dong, Guangming; Pecht, Michael

    2013-04-01

    Rolling element bearing faults are among the main causes of breakdown in rotating machines. In this paper, a rolling bearing fault model is proposed based on the dynamic load analysis of a rotor-bearing system. The rotor impact factor is taken into consideration in the rolling bearing fault signal model. The defect load on the surface of the bearing is divided into two parts, the alternate load and the determinate load. The vibration response of the proposed fault signal model is investigated and the fault signal calculating equation is derived through dynamic and kinematic analysis. Outer race and inner race fault simulations are realized in the paper. The simulation process includes consideration of several parameters, such as the gravity of the rotor-bearing system, the imbalance of the rotor, and the location of the defect on the surface. The simulation results show that different amplitude contributions of the alternate load and determinate load will cause different envelope spectrum expressions. The rotating frequency sidebands will occur in the envelope spectrum in addition to the fault characteristic frequency. This appearance of sidebands will increase the difficulty of fault recognition in intelligent fault diagnosis. The experiments given in the paper have successfully verified the proposed signal model simulation results. The test rig design of the rotor bearing system simulated several operating conditions: (1) rotor bearing only; (2) rotor bearing with loader added; (3) rotor bearing with loader and rotor disk; and (4) bearing fault simulation without rotor influence. The results of the experiments have verified that the proposed rolling bearing signal model is important to the rolling bearing fault diagnosis of rotor-bearing systems.

  15. Reconstruct the past thermocline circulation in the Atlantic: calcification depths and Mg/Ca-temperature calibrations for 6 deep-dwelling planktonic foraminifera

    Science.gov (United States)

    Cleroux, C.; deMenocal, P.; Arbuszewski, J.; Linsley, B.

    2012-04-01

    The subtropical cells are shallow meridional overturning circulations driven by the atmospheric circulation and the deep thermohaline circulation. They connect the mid-latitude and the tropic, release latten heat to the atmosphere and impact climate on decadal to longer time scale. The upper water column temperature and salinity structures of the ocean reflect this circulation. We present proxies to study these past structures. We performed stable oxygen isotope (δ18O) and trace element ratio measurements on one surface-dwelling (G. ruber)1 and six deep-dwelling planktonic foraminifera species (N. dutertrei, G. inflata, G. tumida, G. truncatulinoides, G. hirsuta and G. crassaformis) on 66 coretops spanning from 35°N to 20°S along the Mid-Atlantic ridge. Comparison between measured δ18O and predicted δ18O (using water column temperature and seawater δ18O), shows that N. dutertrei, G. tumida, G. hirsuta and G. crassaformis keep the same apparent calcification depth along the transect (respectively: 125m, 150m, 700m and 800m). Calcification at two depth levels was also tested. For the six deep-dwelling species, we establish Mg/Ca-temperature calibrations with both atlas temperature at the calcification depth and isotopic temperature. We present Mg/Ca-temperature equations for species previously very poorly calibrated. The δ18O and temperature (Mg/Ca derived) on the six planktonic foraminifera species faithfully reproduce the modern water column structure of the upper 800 m depth, establishing promising proxies for past subsurface reconstruction. 1 Arbuszewski, J. J., P. B. deMenocal, A. Kaplan, and C. E. Farmer (2010), On the fidelity of shell-derived δ18Oseawater estimates, Earth and Planetary Science Letters, 300(3-4), 185-196.

  16. Seasonal Trends and Inter-Individual Heterogeneity: A multi-species record of Mg, Sr, Ba, & Mn in Planktic Foraminifera from the Modern Cariaco Basin

    Science.gov (United States)

    Davis, C. V.; Thunell, R.; Astor, Y. M.

    2017-12-01

    The trace element to calcium ratios (TE/Ca) of planktic foraminifera shells are a valuable tool for paleoceanographic reconstructions, and represent a combination of environmental, ecological and biological signals. We present here a three-year record (2010-2013) of TE/Ca (Mg, Sr, Ba, Mn) from four species of foraminifera (Orbulina universa, Globigerina ruber, Globigerinella siphonifera, and Globorotalia menardii) collected by plankton tow in the modern Cariaco basin. Each tow is paired with in situ measurements of water column properties, allowing a direct comparison between shell geochemistry and calcification environment. A combination of Laser Ablation and solution ICP-MS analyses are used to document seasonality, primarily due to the alternating influence of wind-driven coastal upwelling and riverine inputs, in shell TE/Ca. Individual shell data further allows for the quantification of trace element heterogeneity among individual shells within single tows. All TE/Ca ratios vary temporally and show inter-individual variability within single tows. The spread in TE/Ca differs between element and species, with Mg/Ca ratios being the most variable. Despite this, Mg/Ca still tracks temperature changes in G. ruber, O. universa, and G. menardii, with G. ruber most closely reproducing sea surface temperature. Some species show chamber-to-chamber differences in trace element ratios, with G. ruber Mg/Ca and Ba/Ca decreasing in younger chambers (but not other elements) and Mg/Ca, Mn/Ca and Ba/Ca decreasing in younger chambers in G. siphonifera. We find the original Mn/Ca to be variable both temporally and between species, with G. menardii in some samples having extremely high ratios (100 μmol/mol). Assessing seasonal trends and environmental drivers of TE/Ca variability and quantifying the extent of inter-individual heterogeneity in these species will inform the use of their shells as geochemical proxies.

  17. The Effects of Temperature and Salinity on Mg Incorporation in Planktonic Foraminifera Globigerinoides ruber (white): Results from a Global Sediment Trap Mg/Ca Database

    Science.gov (United States)

    Gray, W. R.; Weldeab, S.; Lea, D. W.

    2015-12-01

    Mg/Ca in Globigerinoides ruber is arguably the most important proxy for sea surface temperature (SST) in tropical and sub tropical regions, and as such guides our understanding of past climatic change in these regions. However, the sensitivity of Mg/Ca to salinity is debated; while analysis of foraminifera grown in cultures generally indicates a sensitivity of 3 - 6% per salinity unit, core-top studies have suggested a much higher sensitivity of between 15 - 27% per salinity unit, bringing the utility of Mg/Ca as a SST proxy into dispute. Sediment traps circumvent the issues of dissolution and post-depositional calcite precipitation that hamper core-top calibration studies, whilst allowing the analysis of foraminifera that have calcified under natural conditions within a well constrained period of time. We collated previously published sediment trap/plankton tow G. ruber (white) Mg/Ca data, and generated new Mg/Ca data from a sediment trap located in the highly-saline tropical North Atlantic, close to West Africa. Calcification temperature and salinity were calculated for the time interval represented by each trap/tow sample using World Ocean Atlas 2013 data. The resulting dataset comprises >240 Mg/Ca measurements (in the size fraction 150 - 350 µm), that span a temperature range of 18 - 28 °C and 33.6 - 36.7 PSU. Multiple regression of the dataset reveals a temperature sensitivity of 7 ± 0.4% per °C (p < 2.2*10-16) and a salinity sensitivity of 4 ± 1% per salinity unit (p = 2*10-5). Application of this calibration has significant implications for both the magnitude and timing of glacial-interglacial temperature changes when variations in salinity are accounted for.

  18. The Chicxulub impact is synchronous with the planktonic foraminifera mass extinction at the Cretaceous/Paleogene boundary: new evidence from the Moncada section, Cuba

    Energy Technology Data Exchange (ETDEWEB)

    Arenillas, I.; Arz, J.A.; Grajales-Nishimura, J.M.; Melendez, A.; Rojas-Consuegra, R.

    2016-07-01

    The Moncada section, western Cuba, is one of the few sections across the Cretaceous/Paleogene (K/Pg) boundary in the Gulf of Mexico and Caribbean where an Ir anomaly has been identified toward and above the top of a clastic unit, locally called the Moncada Formation (Fm.). The Moncada Fm. is enriched in ejecta (altered glass spherules, shocked quartz, melt rock fragments, etc.) and represents the local Complex Clastic Unit (CCU) linked to the Chicxulub impact event. This CCU is overlain by a 2-3cm thick bed of Ir-rich, dark, calcareous claystone which represents the “K/T Boundary Clay” at Moncada. All lowermost Danian Planktonic Foraminiferal zones and Acme-Stages (PFAS) were identified, suggesting stratigraphic continuity across the Danian and indicating that the Moncada Fm. is K/Pg boundary in age. High-resolution biostratigraphic data suggest that the mass extinction event of planktonic foraminifera at the K/Pg boundary was more severe than previously suggested. The absence of cosmopolitan, generalist Cretaceous species in the Danian deposits of Moncada supports the hypothesis that only Guembelitria survived the mass extinction triggered by the Chicxulub impact event. The high Ir-concentration and the ejecta-rich clay laminations identified in the lowermost Danian of Moncada (Ancón Fm.) are explained partly as the redeposition of ejecta material eroded and reworked from higher topographic levels, still contaminated by toxic trace elements (e.g., Cu and Ni) of meteoritic origin. These pollutants of meteoritic origin could have affected the ecological conditions of the pelagic environment for thousands of years after the K/Pg boundary, being particularly intense just after the Chicxulub impact. The ecological stress due to the pollutants partly explains the catastrophic mass extinction of planktonic foraminifera at the K/Pg boundary and their subsequent evolutionary radiation. (Author)

  19. Polar bears and sea ice habitat change

    Science.gov (United States)

    Durner, George M.; Atwood, Todd C.; Butterworth, Andy

    2017-01-01

    The polar bear (Ursus maritimus) is an obligate apex predator of Arctic sea ice and as such can be affected by climate warming-induced changes in the extent and composition of pack ice and its impacts on their seal prey. Sea ice declines have negatively impacted some polar bear subpopulations through reduced energy input because of loss of hunting habitats, higher energy costs due to greater ice drift, ice fracturing and open water, and ultimately greater challenges to recruit young. Projections made from the output of global climate models suggest that polar bears in peripheral Arctic and sub-Arctic seas will be reduced in numbers or become extirpated by the end of the twenty-first century if the rate of climate warming continues on its present trajectory. The same projections also suggest that polar bears may persist in the high-latitude Arctic where heavy multiyear sea ice that has been typical in that region is being replaced by thinner annual ice. Underlying physical and biological oceanography provides clues as to why polar bear in some regions are negatively impacted, while bears in other regions have shown no apparent changes. However, continued declines in sea ice will eventually challenge the survival of polar bears and efforts to conserve them in all regions of the Arctic.

  20. Grizzly bear diet shifting on reclaimed mines

    Directory of Open Access Journals (Sweden)

    Bogdan Cristescu

    2015-07-01

    Full Text Available Industrial developments and reclamation change habitat, possibly altering large carnivore food base. We monitored the diet of a low-density population of grizzly bears occupying a landscape with open-pit coal mines in Canada. During 2009–2010 we instrumented 10 bears with GPS radiocollars and compared their feeding on reclaimed coal mines and neighboring Rocky Mountains and their foothills. In addition, we compared our data with historical bear diet for the same population collected in 2001–2003, before extensive mine reclamation occurred. Diet on mines (n=331 scats was dominated by non-native forbs and graminoids, while diets in the Foothills and Mountains consisted primarily of ungulates and Hedysarum spp. roots respectively, showing diet shifting with availability. Field visitation of feeding sites (n=234 GPS relocation clusters also showed that ungulates were the main diet component in the Foothills, whereas on reclaimed mines bears were least carnivorous. These differences illustrate a shift to feeding on non-native forbs while comparisons with historical diet reveal emergence of elk as an important bear food. Food resources on reclaimed mines attract bears from wilderness areas and bears may be more adaptable to landscape change than previously thought. The grizzly bear’s ready use of mines cautions the universal view of this species as umbrella indicative of biodiversity.

  1. Genetic control of biennial bearing in apple

    Science.gov (United States)

    Guitton, Baptiste; Kelner, Jean-Jacques; Velasco, Riccardo; Gardiner, Susan E.; Chagné, David; Costes, Evelyne

    2012-01-01

    Although flowering in mature fruit trees is recurrent, floral induction can be strongly inhibited by concurrent fruiting, leading to a pattern of irregular fruiting across consecutive years referred to as biennial bearing. The genetic determinants of biennial bearing in apple were investigated using the 114 flowering individuals from an F1 population of 122 genotypes, from a ‘Starkrimson’ (strong biennial bearer)בGranny Smith’ (regular bearer) cross. The number of inflorescences, and the number and the mass of harvested fruit were recorded over 6 years and used to calculate 26 variables and indices quantifying yield, precocity of production, and biennial bearing. Inflorescence traits exhibited the highest genotypic effect, and three quantitative trait loci (QTLs) on linkage group (LG) 4, LG8, and LG10 explained 50% of the phenotypic variability for biennial bearing. Apple orthologues of flowering and hormone-related genes were retrieved from the whole-genome assembly of ‘Golden Delicious’ and their position was compared with QTLs. Four main genomic regions that contain floral integrator genes, meristem identity genes, and gibberellin oxidase genes co-located with QTLs. The results indicated that flowering genes are less likely to be responsible for biennial bearing than hormone-related genes. New hypotheses for the control of biennial bearing emerged from QTL and candidate gene co-locations and suggest the involvement of different physiological processes such as the regulation of flowering genes by hormones. The correlation between tree architecture and biennial bearing is also discussed. PMID:21963613

  2. Genomic sequencing of Pleistocene cave bears

    Energy Technology Data Exchange (ETDEWEB)

    Noonan, James P.; Hofreiter, Michael; Smith, Doug; Priest, JamesR.; Rohland, Nadin; Rabeder, Gernot; Krause, Johannes; Detter, J. Chris; Paabo, Svante; Rubin, Edward M.

    2005-04-01

    Despite the information content of genomic DNA, ancient DNA studies to date have largely been limited to amplification of mitochondrial DNA due to technical hurdles such as contamination and degradation of ancient DNAs. In this study, we describe two metagenomic libraries constructed using unamplified DNA extracted from the bones of two 40,000-year-old extinct cave bears. Analysis of {approx}1 Mb of sequence from each library showed that, despite significant microbial contamination, 5.8 percent and 1.1 percent of clones in the libraries contain cave bear inserts, yielding 26,861 bp of cave bear genome sequence. Alignment of this sequence to the dog genome, the closest sequenced genome to cave bear in terms of evolutionary distance, revealed roughly the expected ratio of cave bear exons, repeats and conserved noncoding sequences. Only 0.04 percent of all clones sequenced were derived from contamination with modern human DNA. Comparison of cave bear with orthologous sequences from several modern bear species revealed the evolutionary relationship of these lineages. Using the metagenomic approach described here, we have recovered substantial quantities of mammalian genomic sequence more than twice as old as any previously reported, establishing the feasibility of ancient DNA genomic sequencing programs.

  3. Eastern slopes grizzly bear project : project update

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2002-01-01

    This report updates a study to examine the cumulative effects of human activities on the grizzly bears in the central Canadian Rockies. The project was initiated in 1994 to acquire accurate scientific information on the habitat and populations of grizzly bears in the area of the Banff National Park and Kananaskis Country. This area is probably the most heavily used and developed area where the grizzly still survives. The information gathered throughout the course of the study is used to better protect and manage the bears and other sensitive carnivores in the region. Using telemetry, researchers monitored 25 grizzly bears which were radio-collared in a 22,000 square-kilometer area in the upper Bow Valley drainage of the eastern Alberta slopes. The researchers worked with representatives from Husky Oil and Rigel Energy on the development of the Moose Mountain oil and gas field without adversely affecting the grizzly bear population. Information collected over eight years indicates that the grizzly bears have few and infrequent offspring. Using the information gathered thus far, the location of the Moose Mountain to Jumping Pound pipeline was carefully selected, since the bears suffer from high mortality, and the food and cover had already been compromised by the high number of roads, trails and other human activities in the area. The research concluded in November 2001 provides sufficient information to accurately asses the status of the grizzly bear population and habitat. The data will be analyzed and integrated in 2002 into models that reflect the variables affecting grizzly bears and a final report will be published.

  4. Rotor Vibration Reduction via Active Hybrid Bearings

    DEFF Research Database (Denmark)

    Nicoletti, Rodrigo; Santos, Ilmar

    2002-01-01

    The use of fluid power to reduce and control rotor vibration in rotating machines is investigated. An active hybrid bearing is studied, whose main objective is to reduce wear and vibration between rotating and stationary machinery parts. By injecting pressurised oil into the oil film, through...... orifices machined in the bearing pads, one can alter the machine dynamic characteristics, thus enhancing its operational range. A mathematical model of the rotor-bearing system, as well as of the hydraulic system, is presented. Numerical results of the system frequency response show good agreement...

  5. Microeconomic analysis of military aircraft bearing restoration

    Science.gov (United States)

    Hein, G. F.

    1976-01-01

    The risk and cost of a bearing restoration by grinding program was analyzed. A microeconomic impact analysis was performed. The annual cost savings to U.S. Army aviation is approximately $950,000.00 for three engines and three transmissions. The capital value over an indefinite life is approximately ten million dollars. The annual cost savings for U.S. Air Force engines is approximately $313,000.00 with a capital value of approximately 3.1 million dollars. The program will result in the government obtaining bearings at lower costs at equivalent reliability. The bearing industry can recover lost profits during a period of reduced demand and higher costs.

  6. Superconducting bearings for a LHe transfer pump

    Science.gov (United States)

    Kloeppel, S.; Muehsig, C.; Funke, T.; Haberstroh, C.; Hesse, U.; Lindackers, D.; Zielke, S.; Sass, P.; Schoendube, R.

    2017-12-01

    Superconducting bearings are used in a number of applications for high speed, low loss suspension. Most of these applications suspend a warm shaft and thus require continuous cooling, which leads to additional power consumption. Therefore, it seems advantageous to use these bearings in systems that are inherently cold. One respective application is a submerged pump for the transfer of liquid helium into mobile dewars. Centrifugal pumps require tight sealing clearances, especially for low viscosity fluids and small sizes. This paper covers the design and qualification of superconducting YBCO bearings for a laboratory sized liquid helium transfer pump. Emphasis is given to the axial positioning, which strongly influences the achievable volumetric efficiency.

  7. Camshaft bearing arrangement for overhead cam engine

    Energy Technology Data Exchange (ETDEWEB)

    Yoshikawa, M.

    1985-01-01

    In an assembly for an internal combustion engine comprising a cylinder block, a cylinder head detachably affixed to the cylinder block by a plurality of threaded fastening means, a plurality of poppet valves supported for reciprocation in the cylinder head and a camshaft for operating the poppet valves, the improvement is described comprising a cam carrier detachably affixed to the cylinder head and overlying the threaded fastening means, and a bearing cap affixed to the cam carrier. The cam carrier and the bearing cap have bearing surfaces for journaling the camshaft.

  8. Compressor ported shroud for foil bearing cooling

    Science.gov (United States)

    Elpern, David G [Los Angeles, CA; McCabe, Niall [Torrance, CA; Gee, Mark [South Pasadena, CA

    2011-08-02

    A compressor ported shroud takes compressed air from the shroud of the compressor before it is completely compressed and delivers it to foil bearings. The compressed air has a lower pressure and temperature than compressed outlet air. The lower temperature of the air means that less air needs to be bled off from the compressor to cool the foil bearings. This increases the overall system efficiency due to the reduced mass flow requirements of the lower temperature air. By taking the air at a lower pressure, less work is lost compressing the bearing cooling air.

  9. Public Perceptions of Bears and Management Interventions in Japan

    OpenAIRE

    Sakurai, Ryo; Jacobson, Susan K.

    2011-01-01

    Conservation of bears is a challenge globally. In Japan, Asiatic black bears (Ursus thibetanus) and brown bears (Ursus arctos) are considered a nuisance because of agricultural and property damage and personal human danger due to occasional human casualties. Reduction of human–bear conflicts in Japan would improve long-term conservation of bears and reduce risks to human health and safety. To understand Japanese perceptions of and experience with bears, we analyzed results of 5 public surveys...

  10. Management of brown bears (Ursus arctos) in Europe.

    OpenAIRE

    Klenzendorf, Sybille A.

    1997-01-01

    Management of Brown Bears (Ursus arctos) in Europe. Sybille A. Klenzendorf (Abstract) Successful conservation of brown bears (Ursus arctos) in Europe is associated with public acceptance of damages caused by bears. Recent increases in sheep depredation and beehive damage in central Austria resulted in the deaths of two bears there. Since bear numbers are low in most European populations, alternatives to the elimination of problem bears associated with dam...

  11. State Space Formulation of Nonlinear Vibration Responses Collected from a Dynamic Rotor-Bearing System: An Extension of Bearing Diagnostics to Bearing Prognostics

    OpenAIRE

    Peter W. Tse; Dong Wang

    2017-01-01

    Bearings are widely used in various industries to support rotating shafts. Their failures accelerate failures of other adjacent components and may cause unexpected machine breakdowns. In recent years, nonlinear vibration responses collected from a dynamic rotor-bearing system have been widely analyzed for bearing diagnostics. Numerous methods have been proposed to identify different bearing faults. However, these methods are unable to predict the future health conditions of bearings. To exten...

  12. Molecular phylogeny and SNP variation of polar bears (Ursus maritimus), brown bears (U. arctos), and black bears (U. americanus) derived from genome sequences.

    Science.gov (United States)

    Cronin, Matthew A; Rincon, Gonzalo; Meredith, Robert W; MacNeil, Michael D; Islas-Trejo, Alma; Cánovas, Angela; Medrano, Juan F

    2014-01-01

    We assessed the relationships of polar bears (Ursus maritimus), brown bears (U. arctos), and black bears (U. americanus) with high throughput genomic sequencing data with an average coverage of 25× for each species. A total of 1.4 billion 100-bp paired-end reads were assembled using the polar bear and annotated giant panda (Ailuropoda melanoleuca) genome sequences as references. We identified 13.8 million single nucleotide polymorphisms (SNP) in the 3 species aligned to the polar bear genome. These data indicate that polar bears and brown bears share more SNP with each other than either does with black bears. Concatenation and coalescence-based analysis of consensus sequences of approximately 1 million base pairs of ultraconserved elements in the nuclear genome resulted in a phylogeny with black bears as the sister group to brown and polar bears, and all brown bears are in a separate clade from polar bears. Genotypes for 162 SNP loci of 336 bears from Alaska and Montana showed that the species are genetically differentiated and there is geographic population structure of brown and black bears but not polar bears.

  13. How to live with black bears

    Science.gov (United States)

    Lynn L. Rogers

    1988-01-01

    A black bear in camp requires caution but is not cause for great alarm. Most are timid enough to be scared away by yelling, waving, and banging pans. But a few are too accustomed to people to be bothered.

  14. Centrifuge advances using HTS magnetic bearings

    Science.gov (United States)

    Werfel, F. N.; Flögel-Delor, U.; Rothfeld, R.; Wippich, D.; Riedel, T.

    2001-05-01

    Passive magnetic bearings are of increasing technical interest. We performed experiments with centrifugal rotors to analyze gyroscopic forces in terms imbalance, rotor elasticity and damping. Centrifuge rotors need to be operated soft and stable without whirling the sediments. In order to evaluate optimal parameters critical and resonance behaviors are investigated. Eccentricities up 2 mm are safely passed by accelerating test wheels. In a simple model we describe the effect of passing critical rotational speeds. Measurements of bearing properties and wheel performance are presented. We have constructed a first prototype centrifuge designed with a HTS double bearing which operates a titanium rotor safely up to 30 000 rpm. A 15 W Stirling cooler serves cryogenics of the YBCO stators. From the experiments design guidelines for centrifugal applications with HTS bearings are given.

  15. Hydrostatic radial bearing of centrifugal pump

    International Nuclear Information System (INIS)

    Skalicky, A.

    1976-01-01

    A hydrostatic radial pump is described characterized by the fact that part of the medium off-taken from delivery is used as a lubricating medium. Two additional bodies are placed alongside a hydrostatic bearing with coils in between them and the pump shaft; the coils have an opposite pitch. The feed channel for the hydrostatic bearing pocket is linked to delivery. The coil outlets are connected to the pump suction unit. Two rotating coils placed alongside the hydrostatic bearing will considerably simplify the communication channel design and reduce the dependence on the pump shaft deflections. The addition of another rotating coil in the close vicinity of the pump shaft or directly on the shaft further increases the efficiency. The bearing can be used in designing vertical circulating pumps for the cooling circuits of nuclear reactors. (J.B.)

  16. Ceramic Rail-Race Ball Bearings

    Science.gov (United States)

    Balzer, Mark A.; Mungas, Greg S.; Peters, Gregory H.

    2010-01-01

    Non-lubricated ball bearings featuring rail races have been proposed for use in mechanisms that are required to function in the presence of mineral dust particles in very low-pressure, dry environments with extended life. Like a conventional ball bearing, the proposed bearing would include an inner and an outer ring separated by balls in rolling contact with the races. However, unlike a conventional ball bearing, the balls would not roll in semi-circular or gothic arch race grooves in the rings: instead, the races would be shaped to form two or more rails (see figure). During operation, the motion of the balls would push dust particles into the spaces between the rails where the particles could not generate rolling resistance for the balls

  17. Bearings for the HFIR control plates

    International Nuclear Information System (INIS)

    Abbatiello, A.A.

    1975-08-01

    Recent accelerated wear of HFIR bearings seems to be a more advanced stage of the situation encountered in 1967. The latest observations are in agreement with the hypothesis that high-frequency impact loads at a 30 0 angle on these bearings are the apparent basic cause of their short life. In view of the limited possibilities for change at this stage of HFIR operation, the region of best payoff seems to be an increase in the load-carrying area at some acceptable sacrifice of low rolling friction. On this basis three types of bearings are proposed for test--two of these are journal types and one is a slider type. The next planned shutdown for major parts replacement provides an opportunity to test these modified bearing types in the HFIR under full mechanical operating conditions but without nuclear operation. The program is recommended for consideration and adoption. (U.S.)

  18. Mathematical simulation of bearing ring grinding process

    Science.gov (United States)

    Koltunov, I. I.; Gorbunova, T. N.; Tumanova, M. B.

    2018-03-01

    The paper suggests the method of forming a solid finite element model of the bearing ring. Implementation of the model allowed one to evaluate the influence of the inner cylindrical surface grinding scheme on the ring shape error.

  19. LIGHT-WEIGHT LOAD-BEARING STRUCTURE

    DEFF Research Database (Denmark)

    2009-01-01

    The invention relates to a light-weight load-bearing structure (1) with optimized compression zone (2), where along one or more compression zones (2) in the structure (1) to be cast a core (3) of strong concrete is provided, which core (3) is surrounded by concrete of less strength (4) compared...... to the core (3) of strong concrete. The invention also relates to a method of casting of light-weight load-bearing structures (1) with optimized compression zone (2) where one or more channels, grooves, ducts, pipes and/or hoses (5) formed in the load-bearing structure (1) serves as moulds for moulding one...... or more cores (3) of strong concrete in the light-weight load-bearing structure (1)....

  20. Covalently linked bisporphyrins bearing tetraphenylporphyrin and ...

    Indian Academy of Sciences (India)

    Covalently linked bisporphyrins bearing tetraphenylporphyrin and perbromoporphyrin units: Synthesis and their properties. Puttaiah Bhyrappa V Krishnan ... yields of the TPP moiety. Electrochemical redox and fluorescence data seem to suggest the possible existence of intramolecular interactions in these bisporphyrins.

  1. Cavitation Peening of Aerospace Bearings, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — High-value bearings are a critical part of the safety, reliability, cost and performance of modern aircraft. A typical passenger jet will have 100 to 175 high-valve...

  2. Active magnetic bearings used as exciters for rolling element bearing outer race defect diagnosis.

    Science.gov (United States)

    Xu, Yuanping; Di, Long; Zhou, Jin; Jin, Chaowu; Guo, Qintao

    2016-03-01

    The active health monitoring of rotordynamic systems in the presence of bearing outer race defect is considered in this paper. The shaft is assumed to be supported by conventional mechanical bearings and an active magnetic bearing (AMB) is used in the mid of the shaft location as an exciter to apply electromagnetic force to the system. We investigate a nonlinear bearing-pedestal system model with the outer race defect under the electromagnetic force. The nonlinear differential equations are integrated using the fourth-order Runge-Kutta algorithm. The simulation and experimental results show that the characteristic signal of outer race incipient defect is significantly amplified under the electromagnetic force through the AMBs, which is helpful to improve the diagnosis accuracy of rolling element bearing׳s incipient outer race defect. Copyright © 2016 ISA. Published by Elsevier Ltd. All rights reserved.

  3. Genetic relationships of extant brown bears (Ursus arctos) and polar bears (Ursus maritimus).

    Science.gov (United States)

    Cronin, Matthew A; MacNeil, Michael D

    2012-01-01

    Polar bears (Ursus maritimus) and brown bears (Ursus arctos) are closely related species for which extensive mitochondrial and nuclear phylogenetic comparisons have been made. We used previously published genotype data for 8 microsatellite DNA loci from 930 brown bears in 19 populations and 473 polar bears in 16 populations to compare the population genetic relationships of extant populations of the species. Genetic distances (Nei standard distance = 1.157), the proportion of private alleles (52% of alleles are not shared by the species), and Bayesian cluster analysis are consistent with morphological and life-history characteristics that distinguish polar bears and brown bears as different species with little or no gene flow among extant populations.

  4. Tool Indicates Contact Angles In Bearing Raceways

    Science.gov (United States)

    Akian, Richard A.; Butner, Myles F.

    1995-01-01

    Tool devised for use in measuring contact angles between balls and races in previously operated ball bearings. Used on both inner and outer raceways of bearings having cross-sectional widths between approximately 0.5 and 2.0 in. Consists of integral protractor mounted in vertical plane on bracket equipped with leveling screws and circular level indicator. Protractor includes rotatable indicator needle and set of disks of various sizes to fit various raceway curvatures.

  5. Comments to a polar bear population model

    OpenAIRE

    Øritsland, Nils Are

    1985-01-01

    Larsen, T. & Ugland, K. I. (Polar Research 2 n.s., 117-118) note correctly that a Leslie matrix model treats cubs and females as independent units which is not the case for polar bears. Population projections using the Leslie model with hunting mortalities added are instructive first approximations in evaluations of field data, however, and are recommended as exercises also for polar bear biologists. An APL programme for such projections is available.

  6. Apparatus Would Measure Temperatures Of Ball Bearings

    Science.gov (United States)

    Gibson, John C.; Fredricks, Thomas H.

    1995-01-01

    Rig for testing ball bearings under radial and axial loads and measuring surface temperatures undergoing development. Includes extensible thermocouples: by means of bellows as longitudinal positioners, thermocouples driven into contact with bearing balls to sense temperatures immediately after test run. Not necessary to disassemble rig or to section balls to obtain indirect indications of maximum temperatures reached. Thermocouple measurements indicate temperatures better than temperature-sensitive paints.

  7. Encapsulated Ball Bearings for Rotary Micro Machines

    Science.gov (United States)

    2007-01-01

    occurrence as well as the overall tribological properties of the bearing mechanism. Firstly, the number of stainless steel balls influences not only the load...stacks.iop.org/JMM/17/S224 Abstract We report on the first encapsulated rotary ball bearing mechanism using silicon microfabrication and stainless steel balls...The method of capturing stainless steel balls within a silicon race to support a silicon rotor both axially and radially is developed for rotary micro

  8. Active Vibration Control of Hydrodynamic Journal Bearings

    Science.gov (United States)

    Tůma, J.; Šimek, J.; Škuta, J.; Los, J.; Zavadil, J.

    Rotor instability is one of the most serious problems of high-speed rotors supported by sliding bearings. With constantly increasing parameters, new machines problems with rotor instability are encountered more and more often. Even though there are many solutions based on passive improvement of the bearing geometry to enlarge the operational speed range of the journal bearing, the paper deals with a working prototype of a system for the active vibration control of journal bearings with the use of piezoactuators. The actively controlled journal bearing consists of a movable bushing, which is actuated by two piezoactuators. It is assumed that the journal vibration is measured by a pair of proximity probes. Force produced by piezoactuators and acting at the bushing is controlled according to error signals derived from the proximity probe output signals. The active vibration control was tested with the use of a test rig, which consists of a rotor supported by two controllable journal bearings and driven by an inductive motor up to 23,000 rpm. As it was proved by experiments the active vibration control extends considerably the range of the rotor operational speed.

  9. Consumption choice by bears feeding on salmon.

    Science.gov (United States)

    Gende, S M; Quinn, T P; Willson, M F

    2001-05-01

    Consumption choice by brown (Ursus arctos) and black bears (U. americanus) feeding on salmon was recorded for over 20,000 bear-killed fish from 1994 to 1999 in Bristol Bay (sockeye salmon, Oncorhynchus nerka) and southeastern Alaska (pink, O. gorbuscha and chum salmon O. keta). These data revealed striking patterns of partial and selective consumption that varied with relative availability and attributes of the fish. As the availability of salmon decreased, bears consumed a larger proportion of each fish among both years and habitats. When availability was high (absolute number and density of salmon), bears consumed less biomass per captured fish, targeting energy-rich fish (those that had not spawned) or energy-rich body parts (eggs in females; brain in males). In contrast, individual fish were consumed to a much greater extent, regardless of sex or spawning status, in habitats or years of low salmon availability. The proportion of biomass consumed per fish was similar for males and females, when spawning status was statistically controlled, but bears targeted different body parts: the body flesh, brain and dorsal hump in males and the roe in females. Bears thus appeared to maximize energy intake by modifying the amount and body parts consumed, based on availability and attributes of spawning salmon.

  10. Adaptive Spindle Balancing Using Magnetically Levitated Bearings

    International Nuclear Information System (INIS)

    BARNEY, PATRICK S.; LAUFFER, JAMES P.; PETTEYS, REBECCA; REDMOND, JAMES M.; SULLIVAN, WILLIAM N.

    1999-01-01

    A technological break through for supporting rotating shafts is the active magnetic bearing (AMB). Active magnetic bearings offer some important advantages over conventional ball, roller or journal bearings such as reduced frictional drag, no physical contact in the bearing, no need for lubricants, compatibility with high vacuum and ultra-clean environments, and ability to control shaft position within the bearing. The disadvantages of the AMB system are the increased cost and complexity, reduced bearing stiffness and the need for a controller. Still, there are certain applications, such as high speed machining, biomedical devices, and gyroscopes, where the additional cost of an AMB system can be justified. The inherent actuator capabilities of the AMB offer the potential for active balancing of spindles and micro-shaping capabilities for machine tools, The work presented in this paper concentrates on an AMB test program that utilizes the actuator capability to dynamically balance a spindle. In this study, an unbalanced AMB spindle system was enhanced with an LMS (Least Mean Squares) algorithm combined with an existing PID (proportional, integral, differential) control. This enhanced controller significantly improved the concentricity of an intentionally unbalanced shaft. The study included dynamic system analysis, test validation, control design and simulation, as well as experimental implementation using a digital LMS controller

  11. Hydrostatic bearing with a stepped duct

    International Nuclear Information System (INIS)

    Krevsun, Eh.P.; Ivanov, A.A.

    1975-01-01

    A method for calculating and experimental data from tests on a hydrostatic bearing whose operating hydraulic channel is formed by two cylincrical surfaces, are presented. Unlike currently used hydrostatic bearings, the bearing described has no capillary choke or diaphragm choke at the entrance. This simplifies the construction and increases the reliability, especially when it is operated with corrosive liquids or liquids containing solid suspensoids and causing erosion and blockage of the choke structures. In order to obtain the calculated relations, the flow of a liquid from the bearing in the axial direction to one side through a part of an aperture of unit width was examined. The effect of rotating the axle, of flow in the circumferential direction, and curvature of the aperture was not considered. Isothermal and laminar flows were considered. Because of the simplicity of the hydraulic circuit and the satisfactory properties (bearing capability and flow rate), the bearing described may be used in pumps operating with corrosive liquids, with those containing solid suspensoids and in nuclear energy establishments. (author)

  12. A semi-analytical bearing model considering outer race flexibility for model based bearing load monitoring

    Science.gov (United States)

    Kerst, Stijn; Shyrokau, Barys; Holweg, Edward

    2018-05-01

    This paper proposes a novel semi-analytical bearing model addressing flexibility of the bearing outer race structure. It furthermore presents the application of this model in a bearing load condition monitoring approach. The bearing model is developed as current computational low cost bearing models fail to provide an accurate description of the more and more common flexible size and weight optimized bearing designs due to their assumptions of rigidity. In the proposed bearing model raceway flexibility is described by the use of static deformation shapes. The excitation of the deformation shapes is calculated based on the modelled rolling element loads and a Fourier series based compliance approximation. The resulting model is computational low cost and provides an accurate description of the rolling element loads for flexible outer raceway structures. The latter is validated by a simulation-based comparison study with a well-established bearing simulation software tool. An experimental study finally shows the potential of the proposed model in a bearing load monitoring approach.

  13. Ancient DNA reveals differences in behaviour and sociality between brown bears and extinct cave bears.

    Science.gov (United States)

    Fortes, Gloria G; Grandal-d'Anglade, Aurora; Kolbe, Ben; Fernandes, Daniel; Meleg, Ioana N; García-Vázquez, Ana; Pinto-Llona, Ana C; Constantin, Silviu; de Torres, Trino J; Ortiz, Jose E; Frischauf, Christine; Rabeder, Gernot; Hofreiter, Michael; Barlow, Axel

    2016-10-01

    Ancient DNA studies have revolutionized the study of extinct species and populations, providing insights on phylogeny, phylogeography, admixture and demographic history. However, inferences on behaviour and sociality have been far less frequent. Here, we investigate the complete mitochondrial genomes of extinct Late Pleistocene cave bears and middle Holocene brown bears that each inhabited multiple geographically proximate caves in northern Spain. In cave bears, we find that, although most caves were occupied simultaneously, each cave almost exclusively contains a unique lineage of closely related haplotypes. This remarkable pattern suggests extreme fidelity to their birth site in cave bears, best described as homing behaviour, and that cave bears formed stable maternal social groups at least for hibernation. In contrast, brown bears do not show any strong association of mitochondrial lineage and cave, suggesting that these two closely related species differed in aspects of their behaviour and sociality. This difference is likely to have contributed to cave bear extinction, which occurred at a time in which competition for caves between bears and humans was likely intense and the ability to rapidly colonize new hibernation sites would have been crucial for the survival of a species so dependent on caves for hibernation as cave bears. Our study demonstrates the potential of ancient DNA to uncover patterns of behaviour and sociality in ancient species and populations, even those that went extinct many tens of thousands of years ago. © 2016 John Wiley & Sons Ltd.

  14. Variation in the composition of corals, fishes, sponges, echinoderms, ascidians, molluscs, foraminifera and macroalgae across a pronounced in-to-offshore environmental gradient in the Jakarta Bay-Thousand Islands coral reef complex.

    Science.gov (United States)

    Cleary, D F R; Polónia, A R M; Renema, W; Hoeksema, B W; Rachello-Dolmen, P G; Moolenbeek, R G; Budiyanto, A; Yahmantoro; Tuti, Y; Giyanto; Draisma, S G A; Prud'homme van Reine, W F; Hariyanto, R; Gittenberger, A; Rikoh, M S; de Voogd, N J

    2016-09-30

    Substrate cover, water quality parameters and assemblages of corals, fishes, sponges, echinoderms, ascidians, molluscs, benthic foraminifera and macroalgae were sampled across a pronounced environmental gradient in the Jakarta Bay-Thousand Islands reef complex. Inshore sites mainly consisted of sand, rubble and turf algae with elevated temperature, dissolved oxygen, pH and chlorophyll concentrations and depauperate assemblages of all taxa. Live coral cover was very low inshore and mainly consisted of sparse massive coral heads and a few encrusting species. Faunal assemblages were more speciose and compositionally distinct mid- and offshore compared to inshore. There were, however, small-scale differences among taxa. Certain midshore sites, for example, housed assemblages resembling those typical of the inshore environment but this differed depending on the taxon. Substrate, water quality and spatial variables together explained from 31% (molluscs) to 72% (foraminifera) of the variation in composition. In general, satellite-derived parameters outperformed locally measured parameters. Copyright © 2016 Elsevier Ltd. All rights reserved.

  15. EMP and SIMS studies on Mn/Ca and Fe/Ca systematics in benthic foraminifera from the Peruvian OMZ: a contribution to the identification of potential redox proxies and the impact of cleaning protocols

    OpenAIRE

    Glock, N.; Eisenhauer, A.; Liebetrau, V.; Wiedenbeck, M.; Hensen, C.; Nehrke, G.

    2012-01-01

    In this study we present an initial dataset of Mn/Ca and Fe/Ca ratios in tests of benthic foraminifera from the Peruvian oxygen minimum zone (OMZ) determined with SIMS. These results are a contribution to a better understanding of the proxy potential of these elemental ratios for ambient redox conditions. Foraminiferal tests are often contaminated by diagenetic coatings, like Mn rich carbonate- or Fe and Mn rich (oxyhydr)oxide coatings. Thus, it is substantial to assure that...

  16. Transient Vibration Prediction for Rotors on Ball Bearings Using Load-dependent Non-linear Bearing Stiffness

    Science.gov (United States)

    Fleming, David P.; Poplawski, J. V.

    2002-01-01

    Rolling-element bearing forces vary nonlinearly with bearing deflection. Thus an accurate rotordynamic transient analysis requires bearing forces to be determined at each step of the transient solution. Analyses have been carried out to show the effect of accurate bearing transient forces (accounting for non-linear speed and load dependent bearing stiffness) as compared to conventional use of average rolling-element bearing stiffness. Bearing forces were calculated by COBRA-AHS (Computer Optimized Ball and Roller Bearing Analysis - Advanced High Speed) and supplied to the rotordynamics code ARDS (Analysis of Rotor Dynamic Systems) for accurate simulation of rotor transient behavior. COBRA-AHS is a fast-running 5 degree-of-freedom computer code able to calculate high speed rolling-element bearing load-displacement data for radial and angular contact ball bearings and also for cylindrical and tapered roller beatings. Results show that use of nonlinear bearing characteristics is essential for accurate prediction of rotordynamic behavior.

  17. Polar bears: the fate of an icon.

    Science.gov (United States)

    Fitzgerald, Kevin T

    2013-11-01

    Polar bears are one of the most iconic animals on our planet. Worldwide, even people who would never see one are drawn to these charismatic arctic ice hunters. They are the world's largest terrestrial carnivore, and despite being born on land, they spend most of their lives out on the sea ice and are considered a marine mammal. Current global studies estimate there are around 20,000 animals in some 19 discrete circumpolar populations. Aside from pregnant females denning in the winter months to give birth, the white bears do not hibernate. They spend their winters on the sea ice hunting seals, an activity they are spectacularly adapted for. Research on these animals is incredibly difficult because of the inhospitable surroundings they inhabit and how inaccessible they make the bears. For many years, the sum of our understanding of the natural history of polar bears came from tracks, scats, the remains of their kills, abandoned dens, and anecdotal observations of native hunters, explorers, and early biologists. Nonetheless, the last 40 years have seen a much better picture of their biology emerge thanks to, first, dedicated Canadian researchers and, later, truly international efforts of workers from many countries. Veterinarians have contributed to our knowledge of the bears by delivering and monitoring anesthesia, obtaining blood samples, performing necropsies, investigating their reproduction, conducting radiotelemetry studies, and examining their behavior. Recently, new technologies have been developed that revolutionize the study of the lives and natural history of undisturbed polar bears. These advances include better satellite radiotelemetry equipment and the development of remote-controlled miniature devices equipped with high-definition cameras. Such new modalities provide dramatic new insights into the life of polar bears. The remarkable degree of specialized adaptation to life on the sea ice that allowed the bears to be successful is the very reason that

  18. A circumpolar monitoring framework for polar bears

    Science.gov (United States)

    Vongraven, Dag; Aars, Jon; Amstrup, Steven C.; Atkinson, Stephen N.; Belikov, Stanislav; Born, Erik W.; DeBruyn, T.D.; Derocher, Andrew E.; Durner, George M.; Gill, Michael J.; Lunn, Nicholas J.; Obbard, Martyn E.; Omelak, Jack; Ovsyanikov, Nikita; Peacock, Elizabeth; Richardson, E.E.; Sahanatien, Vicki; Stirling, Ian; Wiig, Øystein

    2012-01-01

    Polar bears (Ursus maritimus) occupy remote regions that are characterized by harsh weather and limited access. Polar bear populations can only persist where temporal and spatial availability of sea ice provides adequate access to their marine mammal prey. Observed declines in sea ice availability will continue as long as greenhouse gas concentrations rise. At the same time, human intrusion and pollution levels in the Arctic are expected to increase. A circumpolar understanding of the cumulative impacts of current and future stressors is lacking, long-term trends are known from only a few subpopulations, and there is no globally coordinated effort to monitor effects of stressors. Here, we describe a framework for an integrated circumpolar monitoring plan to detect ongoing patterns, predict future trends, and identify the most vulnerable polar bear subpopulations. We recommend strategies for monitoring subpopulation abundance and trends, reproduction, survival, ecosystem change, human-caused mortality, human–bear conflict, prey availability, health, stature, distribution, behavioral change, and the effects that monitoring itself may have on polar bears. We assign monitoring intensity for each subpopulation through adaptive assessment of the quality of existing baseline data and research accessibility. A global perspective is achieved by recommending high intensity monitoring for at least one subpopulation in each of four major polar bear ecoregions. Collection of data on harvest, where it occurs, and remote sensing of habitat, should occur with the same intensity for all subpopulations. We outline how local traditional knowledge may most effectively be combined with the best scientific methods to provide comparable and complementary lines of evidence. We also outline how previously collected intensive monitoring data may be sub-sampled to guide future sampling frequencies and develop indirect estimates or indices of subpopulation status. Adoption of this framework

  19. Mass Loss Rates of Fasting Polar Bears.

    Science.gov (United States)

    Pilfold, Nicholas W; Hedman, Daryll; Stirling, Ian; Derocher, Andrew E; Lunn, Nicholas J; Richardson, Evan

    2016-01-01

    Polar bears (Ursus maritimus) have adapted to an annual cyclic regime of feeding and fasting, which is extreme in seasonal sea ice regions of the Arctic. As a consequence of climate change, sea ice breakup has become earlier and the duration of the open-water period through which polar bears must rely on fat reserves has increased. To date, there is limited empirical data with which to evaluate the potential energetic capacity of polar bears to withstand longer fasts. We measured the incoming and outgoing mass of inactive polar bears (n = 142) that were temporarily detained by Manitoba Conservation and Water Stewardship during the open-water period near the town of Churchill, Manitoba, Canada, in 2009-2014. Polar bears were given access to water but not food and held for a median length of 17 d. Median mass loss rates were 1.0 kg/d, while median mass-specific loss rates were 0.5%/d, similar to other species with high adiposity and prolonged fasting capacities. Mass loss by unfed captive adult males was identical to that lost by free-ranging individuals, suggesting that terrestrial feeding contributes little to offset mass loss. The inferred metabolic rate was comparable to a basal mammalian rate, suggesting that while on land, polar bears can maintain a depressed metabolic rate to conserve energy. Finally, we estimated time to starvation for subadults and adult males for the on-land period. Results suggest that at 180 d of fasting, 56%-63% of subadults and 18%-24% of adult males in this study would die of starvation. Results corroborate previous assessments on the limits of polar bear capacity to withstand lengthening ice-free seasons and emphasize the greater sensitivity of subadults to changes in sea ice phenology.

  20. 49 CFR 215.107 - Defective plain bearing box: General.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Defective plain bearing box: General. 215.107... Suspension System § 215.107 Defective plain bearing box: General. A railroad may not place or continue in... the bearing; or (2) Have a detrimental effect on the lubrication of the journal and the bearings. ...

  1. 77 FR 77070 - Black Bear Hydro Partners, LLC;

    Science.gov (United States)

    2012-12-31

    ... DEPARTMENT OF ENERGY Federal Energy Regulatory Commission [Project No. 2727-086] Black Bear Hydro...: October 24, 2012. d. Submitted By: Black Bear Hydro Partners, LLC (Black Bear Hydro). e. Name of Project... designating Black Bear Hydro as the Commission's non-federal representative for carrying out informal...

  2. What Can We Learn?--The Algonquin Bear Attack.

    Science.gov (United States)

    Strickland, Dan

    1992-01-01

    Describes a bear attack in Algonquin Park in Lake Opeongo (Canada) in which a man and woman were killed. Hypothesizes that the bear deliberately preyed on its victims and concludes that the bear was physically normal. Despite this isolated attack, the chance of being attacked by a black bear when camping is virtually nonexistent. (KS)

  3. Wear numbers for ball cup and journal bearings

    NARCIS (Netherlands)

    Ligterink, D.J.; Moes, H.

    1980-01-01

    A wear number is defined for ball cup bearings and for journal bearings where the cup and the cylindrical bearing are made of soft material. This dimensionless wear number provides a relation between the following five quantities: the radius of the ball or the length of the journal bearing in

  4. 46 CFR 61.20-23 - Tailshaft clearance; bearing weardown.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 2 2010-10-01 2010-10-01 false Tailshaft clearance; bearing weardown. 61.20-23 Section...; bearing weardown. (a) Water lubricated bearings, other than rubber, must be rebushed as follows: (1) Where the propelling machinery is located amidship, the after stern tube bearing must be rebushed when it is...

  5. Noise reduction of rotating machinery by viscoelastic bearing supports

    NARCIS (Netherlands)

    Tillema, H.G.

    2003-01-01

    The demand for silent rolling bearing applications, such as electric motors and gearboxes, has resulted in an investigation of viscoelastic bearing supports. By placing a thin viscoelastic layer between the bearing outer ring and the surrounding structure, vibrations of the shaft-bearing arrangement

  6. Bearing assemblies, apparatuses, and motor assemblies using the same

    Science.gov (United States)

    Sexton, Timothy N.; Cooley, Craig H.; Knuteson, Cody W.

    2015-12-29

    Various embodiments of the invention relate to bearing assemblies, apparatuses and motor assemblies that include geometric features configured to impart a selected amount of heat transfer and/or hydrodynamic film formation. In an embodiment, a bearing assembly may include a plurality of superhard bearing pads distributed circumferentially about an axis. At least some of the plurality of superhard bearing pads may include a plurality of sub-superhard bearing elements defining a bearing surface. At least some of the plurality of sub-superhard bearing elements may be spaced from one another by one or more voids to impart a selected amount of heat transfer and hydrodynamic film formation thereon during operation. The bearing assembly may also include a support ring that carries the plurality of superhard bearing pads. In addition, at least a portion of the sub-superhard bearing elements may extend beyond the support ring.

  7. Comment on "Nuclear genomic sequences reveal that polar bears are an old and distinct bear lineage".

    Science.gov (United States)

    Nakagome, Shigeki; Mano, Shuhei; Hasegawa, Masami

    2013-03-29

    Based on nuclear and mitochondrial DNA, Hailer et al. (Reports, 20 April 2012, p. 344) suggested early divergence of polar bears from a common ancestor with brown bears and subsequent introgression. Our population genetic analysis that traces each of the genealogies in the independent nuclear loci does not support the evolutionary model proposed by the authors.

  8. Local Attitudes towards Bear Management after Illegal Feeding and Problem Bear Activity.

    Science.gov (United States)

    Dubois, Sara; Fraser, David

    2013-09-12

    The "pot bears" received international media attention in 2010 after police discovered the intentional feeding of over 20 black bears during the investigation of an alleged marijuana-growing operation in Christina Lake, British Columbia, Canada. A two-phase random digit dialing survey of the community was conducted in 2011 to understand local perspectives on bear policy and management, before and after a summer of problem bear activity and government interventions. Of the 159 households surveyed in February 2011, most had neutral or positive attitudes towards bears in general, and supported the initial decision to feed the food-conditioned bears until the autumn hibernation. In contrast to wildlife experts however, most participants supported relocating the problem bears, or allowing them to remain in the area, ahead of killing; in part this arose from notions of fairness despite the acknowledged problems of relocation. Most locals were aware of the years of feeding but did not report it, evidently failing to see it as a serious form of harm, even after many bears had been killed. This underscores the importance of preventive action on wildlife feeding and the need to narrow the gap between public and expert opinion on the likely effects of relocation versus killing.

  9. Acoustic Emission Monitoring of Incipient in Journal Bearings - Part I : Detectability and measurement for bearing damages

    International Nuclear Information System (INIS)

    Yoon, Dong Jin; Kwon, Oh Yang; Chung, Min Hwa; Kim, Kyung Woong

    1994-01-01

    In contrast to the machinery using rolling element bearings, systems with journal bearings generally operate in large scale and under severe loading condition such as steam generator turbines and internal combustion engines. Failure of the bearings in these machinery can result in the system breakdown. To avoid the time consuming repair and considerable economic loss, the detection of incipient failure in journal bearings becomes very important. In this experimental approach, acoustic emission monitoring is applied to the detection of incipient failure caused by several types of abnormal operating condition most probable in the journal bearing systems. It has been known that the intervention of foreign materials, insufficient lubrication and misassembly etc. are principal factors to cause bearing failure and distress. The experiment was conducted under such designed conditions as hard particles in the lubrication layer, insufficient lubrication, and metallic contact in the simulated journal bearing system. The results showed that acoustic emission could be an effective tool to detect the incipient failure in journal bearings

  10. FRICTION TORQUE IN THE SLIDE BEARINGS

    Directory of Open Access Journals (Sweden)

    BONDARENKO L. N.

    2016-09-01

    Full Text Available Summary. Problem statement. Until now slide bearings are used widely in engineering. But the calculation is made on obsolete method that is based on undetermined parameters such as wear of the bearing shell. It is accepted in the literature that if the shaft and liner material are homogeneous, the workpiece surface are cylindrical as they wear and contact between them occurs at all points contact arc. Research objective. The purpose of this study is determine a friction torque in the slide bearings of power-basis parameters. Conclusions. Since the friction is primarily responsible for wear of cinematic pairs “pin – liner” and “pivot – liner” slide bearings. It is shown that the friction torquesof angles wrap, that are obtained by the formulas and given in literature, are not only qualitatively but also quantitatively, namely, the calculation by literature to the formulas the friction torques are proportional to the angle wrap and the calculation by improved formulas the friction torques are inversely proportional to the angle wrap due to the reduction the normal pressure. Underreporting friction torque at large angle wrap is between 40 and 15 %. The difference in the magnitude of friction torque in the run-in and run-out cinematic pairs with real method of machining is 2...3 %, which it is possible to declare of reducing the finish of contacting surface of slide bearings.

  11. Nonlinear Dynamical Analysis for a Plain Bearing

    Directory of Open Access Journals (Sweden)

    Ali Belhamra

    2014-03-01

    Full Text Available This paper investigates the nonlinear dynamic behavior for a plain classic bearing (fluid bearing lubricated by a non-Newtonian fluid of a turbo machine rotating with high speed; this type of fluid contains additives viscosity (couple-stress fluid film. The solution of the nonlinear dynamic problem of this type of bearing is determined with a spatial discretisation of the modified Reynolds' equation written in dynamic mode by using the optimized short bearing theory and a temporal discretisation for equations of rotor motion by the help of Euler's explicit diagram. This study analyzes the dynamic behavior of a rotor supported by two couple-stress fluid film journal lubricant enhances the dynamic stability of the rotor-bearing system considerably compared to that obtained when using a traditional Newtonian lubricant. The analysis shows that the dynamic behavior of a shaft which turns with high velocities is strongly nonlinear even for poor eccentricities of unbalance; the presence of parameters of couple stress allows strongly attenuating the will synchrony (unbalance and asynchrony (whipping amplitudes of vibrations of the shaft which supports more severe conditions (large unbalances.

  12. Identifying lubricant options for compressor bearing designs

    Science.gov (United States)

    Karnaz, J.; Seeton, C.; Dixon, L.

    2017-08-01

    Today’s refrigeration and air conditioning market is not only driven by the environmental aspects of the refrigerants, but also by the energy efficiency and reliability of system operation. Numerous types of compressor designs are used in refrigeration and air conditioning applications which means that different bearings are used; and in some cases, multiple bearing types within a single compressor. Since only one lubricant is used, it is important to try to optimize the lubricant to meet the various demands and requirements for operation. This optimization entails investigating different types of lubricant chemistries, viscosities, and various formulation options. What makes evaluating these options more challenging is the refrigerant which changes the properties of the lubricant delivered to the bearing. Once the lubricant and refrigerant interaction are understood, through various test methods, then work can start on collaborating with compressor engineers on identifying the lubricant chemistry and formulation options. These interaction properties are important to the design engineer to make decisions on the adequacy of the lubricant before compressor tests are started. This paper will discuss the process to evaluate lubricants for various types of compressors and bearing design with focus on what’s needed for current refrigerant trends. In addition, the paper will show how the lubricant chemistry choice can be manipulated through understanding of the bearing design and knowledge of interaction with the refrigerant to maximize performance. Emphasis will be placed on evaluation of synthetic lubricants for both natural and synthetic low GWP refrigerants.

  13. Wear of rolling element bearings in sodium

    International Nuclear Information System (INIS)

    Campbell, C.S.

    1976-01-01

    Rolling element bearings and related mechanisms are attractive for service in liquid sodium but it is not clear what minimum wear rate can be anticipated. For axially loaded angular contact bearings rotation is incompatible with pure rolling on both races and wear arises from the resulting ball spin. The initial pressure distributions and sizes of the contact ellipses can be calculated but will change with bearing wear. However, the most effective distribution for producing wear would be for the full loads to be borne on the tips of the contact areas, whose maximum length is given by examination of the race wear tracks. A calculation on such a basis should set a lower limit for the wear coefficient. Both the torque and instantaneous wear rate of a bearing will be similar functions of the integral over the contact areas of the product of contact pressure and radius from the ball spin axis. A better estimate of wear coefficient should be obtained by relating the average torque, the average wear, the initial torque and the initial wear where the conditions are known. Analysis of tests in sodium at 400 0 C of high speed steel and Stellite bearings by these methods indicates specific wear rates of the order of 10 -15 m 3 /N-m, not unduly out of line with the range of values found in conventional sliding tests

  14. Core top confirmation of the carbonate ion effect in multiple species of planktic foraminifera and a reassessment of the upper water column equatorial Pacific δ13CFORAM records.

    Science.gov (United States)

    Fehrenbacher, J. S.; Spero, H. J.

    2017-12-01

    Planktic foraminifera carbon (δ13CFORAM) and oxygen (δ18OFORAM) isotope records play a vital role in paleoceanographic reconstructions. The δ18OFORAM values are typically minimally offset from equilibrium δ18O-calcite and are widely applied in oceanographic reconstructions of upper water column hydrography. In contrast, δ13CFORAM are underutilized in paleoceanographic reconstructions. δ13CFORAM are more difficult to interpret due to species-specific δ13CFORAM offsets from the δ13C of the dissolved inorganic carbon of seawater (δ13CDIC). In this study, we analyzed the δ18OFORAM and δ13CFORAM of individual foraminifera shells from a suite of planktic foraminifer species obtained from core top (Holocene) intervals from Eastern Equatorial Pacific (TR163-19), Western Caribbean (ODP 999A), and Equatorial Indian Ocean (ODP 714A) cores. We also include published records from the Western Equatorial Pacific (MW91-9 15GGC). We find the δ13CFORAM offsets from the local water column δ13CDIC are large, variable, region specific, and are correlated to the ambient carbonate ion concentration ([CO32-]) of seawater. We show that the regional offsets from δ13CDIC are due to the carbonate ion effect (CIE) on δ13CFORAM (Spero et al., 1997; Bijma et al., 1999) and variations in water column [CO32-]. More importantly, our results demonstrate that regional and/or culture based δ13CFORAM offsets from δ13CDIC are not applicable globally. Rather, owing to regional differences in water column [CO32-] and species-specific relationships between [CO32-] and δ13CFORAM, δ13CFORAM must be corrected for the regional CIE in order to infer vertical δ13CDIC gradients or to compare δ13CFORAM records from one region to another. Laboratory culture suggests the carbonate ion effect on δ18OFORAM is 1/3 that of δ13CFORAM (Spero et al., 1997). Thus, in order to obtain correct δ18OFORAM temperatures or δ18OSW (when used in conjunction with Mg/Ca) the δ18OFORAM offsets from δ18

  15. Environmental impact of the largest petroleum terminal in SE Brazil: A multiproxy analysis based on sediment geochemistry and living benthic foraminifera.

    Directory of Open Access Journals (Sweden)

    Wânia Duleba

    Full Text Available The Dutos e Terminais do Centro Sul (DTCS is one of the largest petroleum terminals of the South America located in the São Sebastião Channel (SSC on the southeastern Brazilian coast. The aims of this study were to compare the sediment quality near the DTCS with that of several sites in the SSC region including the Araçá (AR domestic sewage outfall and to assess the efficiency of the DTCS wastewater treatment plant. To achieve these goals, textural, geochemical, and living benthic foraminifera results were analyzed for the DTCS, AR, and SSC regions. Sediments in the DTCS area were silty with high concentrations of total organic carbon (1.7-2.4%, total nitrogen (0.2-0.3%, total sulfur (0.4-0.6%, and total (0.12-0.18% and inorganic phosphorous (0.07-0.11%. These values were higher than those in sediments collected in the SSC and Araçá regions. The sediments' concentrations of As, Cd, Cr, Cu, Hg, Ni, Pb, and Zn in the SSC and AR regions were lower than their corresponding probable effect levels (PELs. However, sediments near the DTCS were enriched with As, Cu, and Ni, whose concentrations exceeded their corresponding threshold effect levels (TELs. Around the DTCS outfall diffusers, living foraminiferal densities and diversities were lower than those for the other areas studied. In the DTCS area, it was necessary to search 50 to 190 cm3 of sediment to find 100 live specimens. In the SSC and Araçá areas, a maximum of 40 cm3 of sediment was enough to locate 100 live specimens. The lower density and diversity of living foraminifera around the DTCS than around the other areas illustrates the impact of the environmental stress caused by the presence of pollutants. These results indicate that the wastewater treatment plant efficiency is low and its discharge of pollutants from petrochemical waste liquids affects the benthic fauna around the DTCS in a potentially harmful manner.

  16. Environmental impact of the largest petroleum terminal in SE Brazil: A multiproxy analysis based on sediment geochemistry and living benthic foraminifera

    Science.gov (United States)

    Duleba, Wânia; Teodoro, Andreia C.; Debenay, Jean-Pierre; Gubitoso, Silas; Pregnolato, Leonardo Antônio; Lerena, Laura Misailidis; Prada, Silvio Miranda; Bevilacqua, José Eduardo

    2018-01-01

    The Dutos e Terminais do Centro Sul (DTCS) is one of the largest petroleum terminals of the South America located in the São Sebastião Channel (SSC) on the southeastern Brazilian coast. The aims of this study were to compare the sediment quality near the DTCS with that of several sites in the SSC region including the Araçá (AR) domestic sewage outfall and to assess the efficiency of the DTCS wastewater treatment plant. To achieve these goals, textural, geochemical, and living benthic foraminifera results were analyzed for the DTCS, AR, and SSC regions. Sediments in the DTCS area were silty with high concentrations of total organic carbon (1.7–2.4%), total nitrogen (0.2–0.3%), total sulfur (0.4–0.6%), and total (0.12–0.18%) and inorganic phosphorous (0.07–0.11%). These values were higher than those in sediments collected in the SSC and Araçá regions. The sediments’ concentrations of As, Cd, Cr, Cu, Hg, Ni, Pb, and Zn in the SSC and AR regions were lower than their corresponding probable effect levels (PELs). However, sediments near the DTCS were enriched with As, Cu, and Ni, whose concentrations exceeded their corresponding threshold effect levels (TELs). Around the DTCS outfall diffusers, living foraminiferal densities and diversities were lower than those for the other areas studied. In the DTCS area, it was necessary to search 50 to 190 cm3 of sediment to find 100 live specimens. In the SSC and Araçá areas, a maximum of 40 cm3 of sediment was enough to locate 100 live specimens. The lower density and diversity of living foraminifera around the DTCS than around the other areas illustrates the impact of the environmental stress caused by the presence of pollutants. These results indicate that the wastewater treatment plant efficiency is low and its discharge of pollutants from petrochemical waste liquids affects the benthic fauna around the DTCS in a potentially harmful manner. PMID:29432425

  17. Comparison of fixed-bearing and mobile-bearing total knee arthroplasty after high tibial osteotomy.

    Science.gov (United States)

    Hernigou, Philippe; Huys, Maxime; Pariat, Jacques; Roubineau, François; Flouzat Lachaniette, Charles Henri; Dubory, Arnaud

    2018-02-01

    There is no information comparing the results of fixed-bearing total knee replacement and mobile-bearing total knee replacement in the same patients previously treated by high tibial osteotomy. The purpose was therefore to compare fixed-bearing and mobile-bearing total knee replacements in patients treated with previous high tibial osteotomy. We compared the results of 57 patients with osteoarthritis who had received a fixed-bearing prosthesis after high tibial osteotomy with the results of 41 matched patients who had received a rotating platform after high tibial osteotomy. The match was made for length of follow-up period. The mean follow-up was 17 years (range, 15-20 years). The patients were assessed clinically and radiographically. The pre-operative knee scores had no statistically significant differences between the two groups. So was the case with the intra-operative releases, blood loss, thromboembolic complications and infection rates in either group. There was significant improvement in both groups of knees, and no significant difference was observed between the groups (i.e., fixed-bearing and mobile-bearing knees) for the mean Knee Society knee clinical score (95 and 92 points, respectively), or the Knee Society knee functional score (82 and 83 points, respectively) at the latest follow-up. However, the mean post-operative knee motion was higher for the fixed-bearing group (117° versus 110°). In the fixed-bearing group, one knee was revised because of periprosthetic fracture. In the rotating platform mobile-bearing group, one knee was revised because of aseptic loosening of the tibial component. The Kaplan-Meier survivorship for revision at ten years of follow-up was 95.2% for the fixed bearing prosthesis and 91.1% for the rotating platform mobile-bearing prosthesis. Although we did manage to detect significant differences mainly in clinical and radiographic results between the two groups, we found no superiority or inferiority of the mobile-bearing

  18. Assessing bear-human conflicts in the Yukon Territory

    OpenAIRE

    Lukie, Raechel Dawn

    2010-01-01

    Managing conflicts between bears and humans is vital for human safety and for the conservation of bears. This study investigated black bear (Ursus americanus) and grizzly bear (Ursus arctos) interactions with humans in 18 major communities of the Yukon Territory. I used an information theoretic approach to generate predictive models of the relative potential of bear-human interaction for the 9 conservation officer management regions in the Yukon Territory. I independently modeled interactions...

  19. On the future of controllable fluid film bearings

    DEFF Research Database (Denmark)

    Santos, Ilmar

    2011-01-01

    lubrication regimes, i.e., as tilting-pad journal bearings, multi-recess journal bearings and plain journal bearings. After a comprehensive overview of the theoretical and experimental technological advancements achieved in university laboratories, the feasibility of industrial applications is highlighted......This work gives an overview of the theoretical and experimental achievements of mechatronics applied to fluid film bearings. Compressible and uncompressible fluids are addressed. Rigid and elastic (deformable) bearing profiles are investigated. Hydraulic, pneumatic, magnetic and piezoelectric...

  20. Nuclear fuel handling grapple carriage with self-lubricating bearing

    International Nuclear Information System (INIS)

    Wade, E.E.

    1978-01-01

    Disclosed is a nuclear fuel handling grapple carriage having a bearing with a lubricant reservoir that is capable of being refilled when the bearing and reservoir are submerged in a lubricant pool. The lubricant reservoir supplies lubricant to the bearing while the bearing allows a small amount of lubricant to leak passed appropriately placed seals creating a positive out flow of lubricant thereby preventing foreign material from entering the bearing

  1. Removable bearing arrangement for a wind turbine generator

    Science.gov (United States)

    Bagepalli, Bharat Sampathkumaran; Jansen, Patrick Lee; Gadre, Aniruddha Dattatraya

    2010-06-15

    A wind generator having removable change-out bearings includes a rotor and a stator, locking bolts configured to lock the rotor and stator, a removable bearing sub-assembly having at least one shrunk-on bearing installed, and removable mounting bolts configured to engage the bearing sub-assembly and to allow the removable bearing sub-assembly to be removed when the removable mounting bolts are removed.

  2. Foraminiferal Range Expansions: The Mediterranean Sea as a natural laboratory for climate induced invasions

    Science.gov (United States)

    Hortense Mouanga, Gloria; Langer, Martin R.

    2015-04-01

    Climate change and biological invasions are key processes that modify biodiversity. One of the most severely affected areas of global change is the Mediterranean Sea, where global warming and the opening of the Suez Canal triggered a mass invasion of tropical Red Sea taxa into Mediterranean territories. Climate models prognosticate that the Mediterranean Sea will be one of the most affected ocean regions and may thus serve as a natural laboratory of future global changes. Among the key taxa that are rapidly expanding their latitudinal range in the Mediterranean Sea are symbiont-bearing foraminifera of the genus Amphistegina. Their range expansion strongly correlates with rising sea surface temperatures and mirrors processes of global change. Amphisteginid foraminifera are among the most prolific foraminiferal species and contribute significantly to shallow-water carbonate sediments. Given their prominent environmental role, rapid biogeographic range expansion, and impact on native ecosystems, amphisteginid range expansion and invasion into new territory are likely to trigger changes in ecosystem functioning. Among the uncertainties, it is not known whether all parts of the Mediterranean will be affected equally and to what extent amphisteginid invasions will impact native biotas. We have initiated a new baseline study to explore the effects of invasive amphisteginids on native foraminiferal biotas and to monitor expansion rates and effects on ecosystem functioning along the current range expansion front. We will present new data on recent shift along the range expansion front and discuss cascading effects on community structures and species richness of native foraminiferal biotas. The magnitude and effects that climate change will have on the Mediterranean foraminiferal faunas may ultimately serve as an example of what would happen along expansion fronts in global oceans.

  3. Bear bile: dilemma of traditional medicinal use and animal protection

    Science.gov (United States)

    Feng, Yibin; Siu, Kayu; Wang, Ning; Ng, Kwan-Ming; Tsao, Sai-Wah; Nagamatsu, Tadashi; Tong, Yao

    2009-01-01

    Bear bile has been used in Traditional Chinese Medicine (TCM) for thousands of years. Modern investigations showed that it has a wide range of pharmacological actions with little toxicological side effect and the pure compounds have been used for curing hepatic and biliary disorders for decades. However, extensive consumption of bear bile made bears endangered species. In the 1980's, bear farming was established in China to extract bear bile from living bears with "Free-dripping Fistula Technique". Bear farming is extremely inhumane and many bears died of illness such as chronic infections and liver cancer. Efforts are now given by non-governmental organizations, mass media and Chinese government to end bear farming ultimately. At the same time, systematic research has to be done to find an alternative for bear bile. In this review, we focused on the literature, laboratory and clinical results related to bear bile and its substitutes or alternative in English and Chinese databases. We examined the substitutes or alternative of bear bile from three aspects: pure compounds derived from bear bile, biles from other animals and herbs from TCM. We then discussed the strategy for stopping the trading of bear bile and issues of bear bile related to potential alternative candidates, existing problems in alternative research and work to be done in the future. PMID:19138420

  4. Bear bile: dilemma of traditional medicinal use and animal protection

    Directory of Open Access Journals (Sweden)

    Nagamatsu Tadashi

    2009-01-01

    Full Text Available Abstract Bear bile has been used in Traditional Chinese Medicine (TCM for thousands of years. Modern investigations showed that it has a wide range of pharmacological actions with little toxicological side effect and the pure compounds have been used for curing hepatic and biliary disorders for decades. However, extensive consumption of bear bile made bears endangered species. In the 1980's, bear farming was established in China to extract bear bile from living bears with "Free-dripping Fistula Technique". Bear farming is extremely inhumane and many bears died of illness such as chronic infections and liver cancer. Efforts are now given by non-governmental organizations, mass media and Chinese government to end bear farming ultimately. At the same time, systematic research has to be done to find an alternative for bear bile. In this review, we focused on the literature, laboratory and clinical results related to bear bile and its substitutes or alternative in English and Chinese databases. We examined the substitutes or alternative of bear bile from three aspects: pure compounds derived from bear bile, biles from other animals and herbs from TCM. We then discussed the strategy for stopping the trading of bear bile and issues of bear bile related to potential alternative candidates, existing problems in alternative research and work to be done in the future.

  5. Big bearings. Unsung hero; Kyodaina jikuuke. Hitome ni tsukanai hatarakimono

    Energy Technology Data Exchange (ETDEWEB)

    Nanba, S. [Koyo Seiko Co. Ltd., Osaka (Japan)

    1997-03-05

    This paper introduces examples of the use of big bearings. Bearings are divided largely into those used for radial load supporting and those used for thrust load supporting, while big bearings are often used for the latter usage. Thrust bearings include a cutter heat supporting bearing for tunnel excavator working underground, in addition to those used for swing motion of parabolic antennas and tower cranes. A bearing used in an excavator has an outer diameter of about half that of the excavator. The outer diameter of a shielding machine practically used in tunnel drilling currently has an outer diameter of 14,140 mm, and the outer diameter of the bearing is 7200 mm (bearing weighing 45 tons). Other big thrust bearings may include a swing tower swinging thrust bearing used in a continuous casting facility. Big radial bearings are used in iron and steel making facilities. This paper describes two examples of bearings used in this application. A spherical roller bearing to support converter trunion should be of an ultra big size to withstand total weight of about 1400 tons composed of a converter weight and weight of steel to be processed. A four-row cylindrical roller bearing to support the backup roll of a thick plate rolling mill is a bearing with durability against large loads to support reduction rolls whose size have become increasingly large. 2 refs., 5 figs.

  6. Active Magnetic Bearings – Magnetic Forces

    DEFF Research Database (Denmark)

    Kjølhede, Klaus

    2006-01-01

    Parameter identification procedures and model validation are major steps towards intelligent machines supported by active magnetic bearings (AMB). The ability of measuring the electromagnetic bearing forces, or deriving them from measuring the magnetic flux, strongly contributes to the model...... of the work is the characterization of magnetic forces by using two experimental different experimental approaches. Such approaches are investigated and described in details. A special test rig is designed where the 4 poles - AMB is able to generate forces up to 1900 N. The high precision characterization...... of the magnetic forces are led by using different experimental tests: (I) by using hall sensors mounted directly on the poles (precise measurements of the magnetic flux) and by an auxiliary system, composed of strain gages and flexible beams attached to the rotor; (II) by measuring the input current and bearing...

  7. Robust bearing estimation for 3-component stations

    International Nuclear Information System (INIS)

    CLAASSEN, JOHN P.

    2000-01-01

    A robust bearing estimation process for 3-component stations has been developed and explored. The method, called SEEC for Search, Estimate, Evaluate and Correct, intelligently exploits the inherent information in the arrival at every step of the process to achieve near-optimal results. In particular the approach uses a consistent framework to define the optimal time-frequency windows on which to make estimates, to make the bearing estimates themselves, to construct metrics helpful in choosing the better estimates or admitting that the bearing is immeasurable, and finally to apply bias corrections when calibration information is available to yield a single final estimate. The algorithm was applied to a small but challenging set of events in a seismically active region. It demonstrated remarkable utility by providing better estimates and insights than previously available. Various monitoring implications are noted from these findings

  8. Experimental investigations of active air bearings

    DEFF Research Database (Denmark)

    Santos, Ilmar; Morosi, Stefano

    2012-01-01

    Along with traditional oil lubrication, increasing demand for high-speed applications has renewed attention to gas bearings technology. Traditional aerostatic and aerodynamic gas lubrication has been widely used in a variety of applications, ranging from high-speed spindles to micro and meso......-scale turbomachinery. The present paper deals with experimental rotordynamic testing of a flexible rotor supported by hybrid aerostaticaerodynamic gas journal bearing equipped with an electronic radial air injection system. From a rotordynamic point of view there are two phenomena that limit the widespread...... of traditional gas lubrication: 1) Low damping makes operation across critical speed dangerous, as even low level of unbalance can generate large vibration responses. This is especially problematic for gas bearing applications, which often operate in the supercritical region. Moreover, 2) An upper bound...

  9. Powder metallurgy bearings for advanced rocket engines

    Science.gov (United States)

    Fleck, J. N.; Killman, B. J.; Munson, H.E.

    1985-01-01

    Traditional ingot metallurgy was pushed to the limit for many demanding applications including antifriction bearings. New systems require corrosion resistance, better fatigue resistance, and higher toughness. With conventional processing, increasing the alloying level to achieve corrosion resistance results in a decrease in other properties such as toughness. Advanced powder metallurgy affords a viable solution to this problem. During powder manufacture, the individual particle solidifies very rapidly; as a consequence, the primary carbides are very small and uniformly distributed. When properly consolidated, this uniform structure is preserved while generating a fully dense product. Element tests including rolling contact fatigue, hot hardness, wear, fracture toughness, and corrosion resistance are underway on eleven candidate P/M bearing alloys and results are compared with those for wrought 440C steel, the current SSME bearing material. Several materials which offer the promise of a significant improvement in performance were identified.

  10. Big Bear Exploration Ltd. 1998 annual report

    International Nuclear Information System (INIS)

    1999-01-01

    During the first quarter of 1998 Big Bear completed a purchase of additional assets in the Rainbow Lake area of Alberta in which light oil purchase was financed with new equity and bank debt. The business plan was to immediately exploit these light oil assets, the result of which would be increased reserves, production and cash flow. Although drilling results in the first quarter on the Rainbow Lake properties was mixed, oil prices started to free fall and drilling costs were much higher than expected. As a result, the company completed a reduced program which resulted in less incremental loss and cash flow than it budgeted for. On April 29, 1998, Big Bear entered into agreement with Belco Oil and Gas Corp. and Moan Investments Ltd. for the issuance of convertible preferred shares at a gross value of $15,750,000, which shares were eventually converted at 70 cents per share to common equity. As a result of the continued plunge in oil prices, the lending value of the company's assets continued to fall, requiring it to take action in order to meet its financial commitments. Late in the third quarter Big Bear issued equity for proceeds of $11,032,000 which further reduced the company's debt. Although the company has been extremely active in identifying and pursuing acquisition opportunities, it became evident that Belco Oil and Gas Corp. and Big Bear did nor share common criteria for acquisitions, which resulted in the restructuring of their relationship in the fourth quarter. With the future of oil prices in question, Big Bear decided that it would change its focus to that of natural gas and would refocus ts efforts to acquire natural gas assets to fuel its growth. The purchase of Blue Range put Big Bear in a difficult position in terms of the latter's growth. In summary, what started as a difficult year ended in disappointment

  11. Grizzly bear habitat selection is scale dependent.

    Science.gov (United States)

    Ciarniello, Lana M; Boyce, Mark S; Seip, Dale R; Heard, Douglas C

    2007-07-01

    The purpose of our study is to show how ecologists' interpretation of habitat selection by grizzly bears (Ursus arctos) is altered by the scale of observation and also how management questions would be best addressed using predetermined scales of analysis. Using resource selection functions (RSF) we examined how variation in the spatial extent of availability affected our interpretation of habitat selection by grizzly bears inhabiting mountain and plateau landscapes. We estimated separate models for females and males using three spatial extents: within the study area, within the home range, and within predetermined movement buffers. We employed two methods for evaluating the effects of scale on our RSF designs. First, we chose a priori six candidate models, estimated at each scale, and ranked them using Akaike Information Criteria. Using this method, results changed among scales for males but not for females. For female bears, models that included the full suite of covariates predicted habitat use best at each scale. For male bears that resided in the mountains, models based on forest successional stages ranked highest at the study-wide and home range extents, whereas models containing covariates based on terrain features ranked highest at the buffer extent. For male bears on the plateau, each scale estimated a different highest-ranked model. Second, we examined differences among model coefficients across the three scales for one candidate model. We found that both the magnitude and direction of coefficients were dependent upon the scale examined; results varied between landscapes, scales, and sexes. Greenness, reflecting lush green vegetation, was a strong predictor of the presence of female bears in both landscapes and males that resided in the mountains. Male bears on the plateau were the only animals to select areas that exposed them to a high risk of mortality by humans. Our results show that grizzly bear habitat selection is scale dependent. Further, the

  12. The sweet lung: Chewing gummi bear aspiration.

    Science.gov (United States)

    Tavladaki, Theonimfi; Fitrolaki, Michaela-Diana; Spanaki, Anna-Maria; Ilia, Staurula; Geromarkaki, Elissabet; Briassoulis, George

    2012-07-01

    Inhalation of foreign bodies, a leading cause of accidental death, is most common in preschool children. In this article we report our experience with a 5-year-old Greek girl who presented with a 24-hour history of sore throat, chest pain, and shortness of breath. Emergency bronchoscopy was performed and multiple small chewing gummi bear (HARIBO) particles impacted in the orifices of the right main bronchus and right lobar and segmentalinic bronchi were successfully removed and aspirated. Aspiration of gummi bears, which is for the first time reported, may cause a silent choking episode leading to life-threatening bronchi obstruction at multiple sites, even in children older than 4 years.

  13. Closure Welding of Plutonium Bearing Storage Containers

    International Nuclear Information System (INIS)

    Cannell, G.R.

    2002-01-01

    A key element in the Department of Energy (DOE) strategy for the stabilization, packaging and storage of plutonium-bearing materials involves closure welding of DOE-STD-3013 Outer Containers (3013 container). The 3013 container provides the primary barrier and pressure boundary preventing release of plutonium-bearing materials to the environment. The final closure (closure weld) of the 3013 container must be leaktight, structurally sound and meet DOE STD 3013 specified criteria. This paper focuses on the development, qualification and demonstration of the welding process for the closure welding of Hanford PFP 3013 outer containers

  14. Hydrodynamic bearing lubricated with magnetic fluids

    International Nuclear Information System (INIS)

    Urreta, H; Leicht, Z; Sanchez, A; Agirre, A; Kuzhir, P; Magnac, G

    2009-01-01

    This paper summarizes the work carried out in the development of hydrodynamic lubricated journal bearings with magnetic fluids. Two different fluids have been analyzed, one ferrofluid from FERROTEC APG s10n and one magnetorheological fluid from LORD Corp., MRF122-2ED. Theoretical analysis has been carried out with numerical solutions of Reynolds equation, based on apparent viscosity modulation for ferrofluid and Bingham model for MR fluid. To validate this model, one test bench has been designed, manufactured and set up, where preliminary results shown in this paper demonstrate that magnetic fluids can be used to develop active journal bearings.

  15. R+D works for the further development of high temperature reactors. (1) Captive bearing experiments for active magnetic bearings. (2) Captive bearing test for HTR blowers

    International Nuclear Information System (INIS)

    1991-01-01

    When using active magnetic bearings as blower shaft bearings, blower motors and bearings must be protected against mechanical damage in case of faults (example: total electrical supply failure due to the supply cables breaking). So-called captive bearings are provided, in order to be able to shut the blowers down safely in such faults. These captive bearings are roller bearings which are additionally fitted in the area of the blower shaft bearings, to prevent mechanical contact between the blower rotor and stator. As there was little experience available for the given boundary conditions, such as - speed, - acceleration, - bearing load, - bearing dimensions, - ambient conditions, appropriate development and tests had to be carried out. It was important to determine suitable captive bearings and the necessary ambient conditions, which will make it possible to support the failures of the magnetic bearings to be expected in 40 years' operation of the reactor without damage and to meet the requirements of the captive bearings. (orig./GL) [de

  16. REPLICAÇÃO DE FÓSSEIS DE FORAMINIFERA UTILIZANDO REAPROVEITAMENTO DE “ISOPOR” COM ALUNOS DO IFPB-CG

    Directory of Open Access Journals (Sweden)

    Hermes de Oliveira Machado Filho

    2011-09-01

    Full Text Available Os fósseis são unidades paleontológicas preciosas e difíceis de serem coletadas para pesquisas ou principalmente para aulas práticas sobre o passado geológica da Terra. Desta forma, lançam-se mão de técnicas alternativas para se fazer réplicas dessas unidades. O presente artigo vem apresentar atividades de sistemática paleozoológica, utilizando o “isopor” como matéria prima para confecção de modelos de fósseis em aulas práticas para a comunidade escolar do Instituto Federal de Educação, Ciência e Tecnologia da Paraíba, campus de Campina Grande. Dessa forma, o instituto está iniciando a construção de um acervo visual 3D alternativo de fósseis guia do grupo dos Foraminifera, em específico, os bioindicadores de petróleo, além de contribuir para reutilização de resíduos sólidos poluidores ao meio ambiente.

  17. Late Paleocene-middle Eocene benthic foraminifera on a Pacific seamount (Allison Guyot, ODP Site 865): Greenhouse climate and superimposed hyperthermal events

    Science.gov (United States)

    Arreguín-Rodríguez, Gabriela J.; Alegret, Laia; Thomas, Ellen

    2016-03-01

    We investigated the response of late Paleocene-middle Eocene (~60-37.5 Ma) benthic foraminiferal assemblages to long-term climate change and hyperthermal events including the Paleocene-Eocene Thermal Maximum (PETM) at Ocean Drilling Program (ODP) Site 865 on Allison Guyot, a seamount in the Mid-Pacific Mountains. Seamounts are isolated deep-sea environments where enhanced current systems interrupt bentho-pelagic coupling, and fossil assemblages from such settings have been little evaluated. Assemblages at Site 865 are diverse and dominated by cylindrical calcareous taxa with complex apertures, an extinct group which probably lived infaunally. Dominance of an infaunal morphogroup is unexpected in a highly oligotrophic setting, but these forms may have been shallow infaunal suspension feeders, which were ecologically successful on the current-swept seamount. The magnitude of the PETM extinction at Site 865 was similar to other sites globally, but lower diversity postextinction faunas at this location were affected by ocean acidification as well as changes in current regime, which might have led to increased nutrient supply through trophic focusing. A minor hyperthermal saw less severe effects of changes in current regime, with no evidence for carbonate dissolution. Although the relative abundance of infaunal benthic foraminifera has been used as a proxy for surface productivity through bentho-pelagic coupling, we argue that this proxy can be used only in the absence of changes in carbonate saturation and current-driven biophysical linking.

  18. Impact of Fixed-Bearing and Mobile-Bearing Tibial Insert in Unicondylar Knee Arthroplasty

    Directory of Open Access Journals (Sweden)

    Mehmet Faruk Çatma

    2016-06-01

    Full Text Available INTRODUCTION: The aim of the study is to investigate the impact of fixed or mobile-bearing tibial inserts on patellofemoral arthrosis and evaluate which one to be preferred for patients with patellofemoral arthrosis. METHODS: Operated in our clinic between January 2009 and February 2013, 33 with patellofemoral arthritis together with anteromedial compartment arthritis were included in the study. Patellofemoral joints of patients were evaluated according to the scoring system defined by Fulkerson-Shea. RESULTS: Unicondylar knee arthroplasty with fixed-bearing tibial insertsand 22 (66,6% (male: 3, female: 19 and unicondylar knee arthroplasty with mobile-bearing tibial inserts 11 (33,9 % (male: 2, female: 9 were implanted.Average knee flexion was found to be 116,5 (100-135 degrees in 22 patients with mobile-bearing tibial inserts, and 114,5 (95-135 in 11 patients with fixed-bearing tibial inserts. DISCUSSION AND CONCLUSION: Patellofemoral arthrosis is an important factor for unicondylar knee arthroplasty prognosis and one of the determinants of patient satisfaction. Significantly less patellofemoral complaints were seen with UKA with fixed-bearing tibial insert compared to mobile-bearing tibial insert.

  19. Local Attitudes towards Bear Management after Illegal Feeding and Problem Bear Activity

    Directory of Open Access Journals (Sweden)

    David Fraser

    2013-09-01

    Full Text Available The “pot bears” received international media attention in 2010 after police discovered the intentional feeding of over 20 black bears during the investigation of an alleged marijuana-growing operation in Christina Lake, British Columbia, Canada. A two-phase random digit dialing survey of the community was conducted in 2011 to understand local perspectives on bear policy and management, before and after a summer of problem bear activity and government interventions. Of the 159 households surveyed in February 2011, most had neutral or positive attitudes towards bears in general, and supported the initial decision to feed the food-conditioned bears until the autumn hibernation. In contrast to wildlife experts however, most participants supported relocating the problem bears, or allowing them to remain in the area, ahead of killing; in part this arose from notions of fairness despite the acknowledged problems of relocation. Most locals were aware of the years of feeding but did not report it, evidently failing to see it as a serious form of harm, even after many bears had been killed. This underscores the importance of preventive action on wildlife feeding and the need to narrow the gap between public and expert opinion on the likely effects of relocation versus killing.

  20. Geometric modeling in the problem of ball bearing accuracy

    Science.gov (United States)

    Glukhov, V. I.; Pushkarev, V. V.; Khomchenko, V. G.

    2017-06-01

    The manufacturing quality of ball bearings is an urgent problem for machine-building industry. The aim of the research is to improve the geometric specifications accuracy of bearings based on evidence-based systematic approach and the method of adequate size, location and form deviations modeling of the rings and assembled ball bearings. The present work addressed the problem of bearing geometric specifications identification and the study of these specifications. The deviation from symmetric planar of rings and bearings assembly and mounting width are among these specifications. A systematic approach to geometric specifications values and ball bearings tolerances normalization in coordinate systems will improve the quality of bearings by optimizing and minimizing the number of specifications. The introduction of systematic approach to the international standards on rolling bearings is a guarantee of a significant increase in accuracy of bearings and the quality of products where they are applied.

  1. Diet and morphology of extant and recently extinct northern bears

    Science.gov (United States)

    Mattson, David J.

    1998-01-01

    I examined the relationship of diets to skull morphology of extant northern bears and used this information to speculate on diets of the recently extinct cave (Ursus spelaeus) and short-faced (Arctodus simus) bears. Analyses relied upon published skull measurements and food habits of Asiatic (U. thibetanus) and American (U. americanus) black bears, polar bears (U. maritimus), various subspecies of brown bears (U. arctos), and the giant panda (Ailuropoda melanoleuca). Principal components analysis showed major trends in skull morphology related to size, crushing force, and snout shape. Giant pandas, short-faced bears, cave bears, and polar bears exhibited extreme features along these gradients. Diets of brown bears in colder, often non-forested environments were distinguished by large volumes of roots, foliage, and vertebrates, while diets of the 2 black bear species and brown bears occupying broadleaf forests contained greater volumes of mast and invertebrates and overlapped considerably. Fractions of fibrous foods in feces (foliage and roots) were strongly related to skull morphology (R2=0.97)">(R2=0.97). Based on this relationship, feces of cave and short-faced bears were predicted to consist almost wholly of foliage, roots, or both. I hypothesized that cave bears specialized in root grubbing. In contrast, based upon body proportions and features of the ursid digestive tract, I hypothesized that skull features associated with crushing force facilitated a carnivorous rather than herbivorous diet for short-faced bears.

  2. The economics of roadside bear viewing

    Science.gov (United States)

    Richardson, Leslie; Rosen, Tatjana; Gunther, Kerry; Schwartz, Chuck

    2014-01-01

    Viewing bears along roadside habitats is a popular recreational activity in certain national parks throughout the United States. However, safely managing visitors during traffic jams that result from this activity often requires the use of limited park resources. Using unique visitor survey data, this study quantifies economic values associated with roadside bear viewing in Yellowstone National Park, monetary values that could be used to determine whether this continued use of park resources is warranted on economic grounds. Based on visitor expenditure data and results of a contingent visitation question, it is estimated that summer Park visitation would decrease if bears were no longer allowed to stay along roadside habitats, resulting in a loss of 155 jobs in the local economy. Results from a nonmarket valuation survey question indicate that on average, visitors to Yellowstone National Park are willing to pay around $41 more in Park entrance fees to ensure that bears are allowed to remain along roads within the Park. Generalizing this value to the relevant population of visitors indicates that the economic benefits of allowing this wildlife viewing opportunity to continue could outweigh the costs of using additional resources to effectively manage these traffic jams.

  3. Bearing capacity check of aluminum profiles

    Directory of Open Access Journals (Sweden)

    Cristian Grigoraşenco

    2013-06-01

    Full Text Available Because of suspended ceiling options to be customizable they are the choice for implementation in spaces like offices buildings, schools, hospitals and commercial premises. Recent problems with suspended gypsum ceilings falling in some commercial premises led to verification by tensile test and flexural bearing capacity of 5 types of aluminum elements used to suspend the ceilings.

  4. Minimization and identification of conducted emission bearing ...

    Indian Academy of Sciences (India)

    high frequency line to ground current or common mode current and hence bearing current; introducing ... The draw back of the filter method is the ... isolated for its successful operation and this is not possible in many process/engineering ... In the push-pull amplifier, the IGBTs (the IGBTs are used in the switch mode and not.

  5. Method of treating oil-bearing shale

    Energy Technology Data Exchange (ETDEWEB)

    Freeman, N H

    1926-04-14

    The process is given for treating shale or other oil-bearing mineral which consists of the application of dry heat to render the oil soluble and subjects the product of the heat treatment to an operation to extract the soluble oils.

  6. Angular-momentum-bearing modes in fission

    International Nuclear Information System (INIS)

    Moretto, L.G.; Peaslee, G.F.; Wozniak, G.J.

    1989-03-01

    The angular-momentum-bearing degrees of freedom involved in the fission process are identified and their influence on experimental observables is discussed. The excitation of these modes is treated in the ''thermal'' limit, and the resulting distributions of observables are calculated. Experiments demonstrating the role of these modes are presented and discussed. 61 refs., 12 figs

  7. Load-Bearing Capacity of Roof Trusses

    DEFF Research Database (Denmark)

    Sørensen, John Dalsgaard; Damkilde, Lars; Munch-Andersen, J.

    2004-01-01

    systems such as roof trusses are established and statistical characteristics of the load bearing capacity are determined. The results show that there is a significant increase in the characteristic (nominal) value and a reduction in the coefficient of variation (COV) for typical loads such as permanent...

  8. Self-lubricating fluid bearing assembly

    International Nuclear Information System (INIS)

    Kapich, D.D.

    1981-01-01

    A sealed self-lubricating fluid bearing assembly is described for circulating fluid in the form of a gas coolant in a nuclear reactor, the power for the circulator being provided by a shaft located within the primary containment vessel. In such a system the reactor coolant is isolated from the fluid region at the far end of the drive shaft. (U.K.)

  9. Telemetry experiments with a hibernating black bear

    Science.gov (United States)

    Craighead, J. J.; Varney, J. R.; Sumner, J. S.; Craighead, F. C., Jr.

    1972-01-01

    The objectives of this research were to develop and test telemetry equipment suitable for monitoring physiological parameters and activity of a hibernating bear in its den, to monitor this data and other environmental information with the Nimbus 3 IRLS data collection system, and to refine immobilizing, handling, and other techniques required in future work with wild bears under natural conditions. A temperature-telemetering transmitter was implanted in the abdominal cavity of a captive black bear and body temperature data was recorded continuously during a 3 month hibernation period. Body temperatures ranging between 37.5 and 31.8 C were observed. Body temperature and overall activity were influenced by disturbances and ambient den temperature. Nychthemeral temperature changes were not noticable. A load cell weight recording device was tested for determining weight loss during hibernation. Monitoring of data by satellite was not attempted. The implanted transmitter was removed and the bear was released with a radiolocation collar at the conclusion of the experiment.

  10. Additive Manufacturing for Low Volume Bearings

    Energy Technology Data Exchange (ETDEWEB)

    Tate, John G. [Schaeffler Group USA, Spartanburg, SC (United States); Richardson, Bradley S. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Love, Lonnie J. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2017-09-01

    ORNL worked with the Schaeffler Group USA to explore additive manufacturing techniques that might be appropriate for prototyping of bearing cages. Multiple additive manufacturing techniques were investigated, including e-beam, binder jet and multiple laser based processes. The binder jet process worked best for the thin, detailed cages printed.

  11. Thermo-hydrodynamic lubrication in hydrodynamic bearings

    CERN Document Server

    Bonneau, Dominique; Souchet, Dominique

    2014-01-01

    This Series provides the necessary elements to the development and validation of numerical prediction models for hydrodynamic bearings. This book describes the thermo-hydrodynamic and the thermo-elasto-hydrodynamic lubrication. The algorithms are methodically detailed and each section is thoroughly illustrated.

  12. Experimental investigation of gas aerostatic bearings

    Czech Academy of Sciences Publication Activity Database

    Steinbauer, P.; Šika, Z.; Kozánek, Jan; Šimek, J.

    2008-01-01

    Roč. 3, - (2008), s. 769-776 ISSN 1335-2393 R&D Projects: GA ČR GA101/06/1787 Institutional research plan: CEZ:AV0Z20760514 Keywords : aerostatic bearing * experimental identification * measurement Subject RIV: BI - Acoustics

  13. An Interview About Hunting a Black Bear

    OpenAIRE

    G.yu lha

    2009-01-01

    The respondent describes the first time he killed a black bear while hunting. The fifty one audio and nine video files in this collection include: villages’ life stories, circle-dancing songs and performance, local history, folk tales, and interviews from Siyuewu Village, Puxi Township, Rangtang County, Aba Tibetan and Qiang Autonomous Prefecture, Sichuan Province, China. World Oral Literature Project

  14. Heavy Bearings Exploitation Energy and Reduction Methods

    Science.gov (United States)

    Szekely, V. G.; Cioară, R.

    2016-11-01

    The global trend of resource conservation so as “not to compromise the ability of future generation's development” is the fundamental basis of the concept of sustainable development. Concordant with this, the energy efficiency of products is increasingly discussed and frequently taken into account in the design stage. In more cases a product is more appreciated and more attractive as the energy consumption and its associated materials are lower. In the production stage, said consumption advantages primarily the manufacturer, particularly through low consumption thereof. In the operational phase, low energy and materials consumption represents an user advantage and it's a major argument in the decision to purchase and use a particular product. Heavy bearings are frequent products used in wind turbines that are producing non-conventional “clean” energy, as windmills. An enhanced energy efficiency bearing contributes to the enhancement of the overall efficiency of the wind turbines. Based on a suitable mathematical model, this paper identifies and recommends courses of action to reduce the operating energy of heavy bearing through the “cage” - which is the subject of a much larger research - with the highest priority. The identified actions may constitute from a set of requirements for the design stage of the heavy bearing predominantly oriented towards innovation-invention.

  15. Extended Life Testing of Duplex Ball Bearings

    Science.gov (United States)

    Mobley, Jeffrey; Robertson, Michael; Hodges, Charles

    2016-01-01

    Sierra Nevada Corporation’s Space Systems performed bearing life testing for the Scan Mirror Motor/Encoder Assembly (SMMA), part of the Scan Mirror Assembly on-board the Aerosol Polarimetry Sensor (APS) on the NASA Glory Spacecraft. The baseline bearing life test duration extended beyond the launch date for the Glory Spacecraft; a risk that the program was willing to undertake with the understanding that if any anomalies or failures occurred before the required life was achieved, then the mission objectives or operating profile could be modified on orbit to take those results into account. Even though the Glory Spacecraft failed to reach orbit during its launch in March of 2011, the bearing life testing was continued through a mutual understanding of value between Sierra Nevada Corporation and our customer; with a revised goal of testing to failure rather than completing a required number of life cycles. Life testing thus far has not only exceeded the original mission required life, but has also exceeded the published test data for Cumulative Degradation Factor (CDF) from NASA/CR-2009-215681. Many lessons were learned along the way regarding long life testing. The bearing life test has been temporarily suspended due to test support equipment issues.

  16. Load Bearing Equipment for Bone and Muscle

    Science.gov (United States)

    Shackelford, Linda; Griffith, Bryan

    2015-01-01

    Resistance exercise on ISS has proven effective in maintaining bone mineral density and muscle mass. Exploration missions require exercise with similar high loads using equipment with less mass and volume and greater safety and reliability than resistance exercise equipment used on ISS (iRED, ARED, FWED). Load Bearing Equipment (LBE) uses each exercising person to create and control the load to the partner.

  17. Geologic feasibility of selected chalk-bearing sequences within the conterminous United States with regard to siting of radioactive-waste repositories

    International Nuclear Information System (INIS)

    Gonzales, S.

    1975-11-01

    Various geologic and hydrologic parameters are evaluated in relation to assessing the potential for repository storage of high-level radioactive wastes within several stratigraphic sequences dominated by chalks and chalky limestones. The former lithology is defined as a carbonate rock consisting mainly of very fine-grained particles of micritic calcite. Although chalks also contain coarser-grained particles such as shells of fossil foraminifera and non-calcitic minerals like quartz, most contain more than 90 percent micritic material. The latter represents broken fossil coccolith plates. The chalk-dominated formations discussed are exposed and underlie two different physiographic provinces which nevertheless display a general similarity in both being regions of extensive plains. The Niobrara Formation occurs mainly within the Great Plains province, while the Austin Chalk of Texas and the Selma Group of Alabama and Mississippi are located in the western and eastern Gulf Coastal Plain, respectively. The preliminary assessment is that chalk-bearing sequences show some promise and are deserving of added consideration and evaluation. Containment for hundreds of thousands of years would seem possible given certain assumptions. The most promising units from the three studied are the Niobrara Formation and Selma Group. Regional and local conditions make the Austin more suspect

  18. Hybrid bearings for LH2 and LO2 turbopumps

    Science.gov (United States)

    Butner, M. F.; Lee, F. C.

    1985-01-01

    Hybrid combinations of hydrostatic and ball bearings can improve bearing performance for liquid hydrogen and liquid oxygen turbopumps. Analytic studies were conducted to optimize hybrid bearing designs for the SSME-type turbopump conditions. A method to empirically determine damping coefficients was devised. Four hybrid bearing configurations were designed, and three were fabricated. Six hybrid and hydrostatic-only bearing configurations will be tested for steady-state and transient performance, and quantification of damping coefficients. The initial tests were conducted with the liquid hydrogen bearing.

  19. Fault tolerant homopolar magnetic bearings with flux invariant control

    International Nuclear Information System (INIS)

    Na, Uhn Joo

    2006-01-01

    The theory for a novel fault-tolerant 4-active-pole homopolar magnetic bearing is developed. If any one coil of the four coils in the bearing actuator fail, the remaining three coil currents change via an optimal distribution matrix such that the same opposing pole, C-core type, control fluxes as those of the un-failed bearing are produced. The homopolar magnetic bearing thus provides unaltered magnetic forces without any loss of the bearing load capacity even if any one coil suddenly fails. Numerical examples are provided to illustrate the novel fault-tolerant, 4-active pole homopolar magnetic bearings

  20. Direct Model Reference Adaptive Control for a Magnetic Bearing

    Energy Technology Data Exchange (ETDEWEB)

    Durling, Mike [Rensselaer Polytechnic Inst., Troy, NY (United States)

    1999-11-01

    A Direct Model Reference Adaptive Controller (DMRAC) is applied to a magnetic bearing test stand. The bearing of interest is the MBC 500 Magnetic Bearing System manufactured by Magnetic Moments, LLC. The bearing model is presented in state space form and the system transfer function is measured directly using a closed-loop swept sine technique. Next, the bearing models are used to design a phase-lead controller, notch filter and then a DMRAC. The controllers are tuned in simulations and finally are implemented using a combination of MATLAB, SIMULINK and dSPACE. The results show a successful implementation of a DMRAC on the magnetic bearing hardware.

  1. Thermohydrodynamic analysis of cryogenic liquid turbulent flow fluid film bearings

    Science.gov (United States)

    Andres, Luis San

    1993-01-01

    A thermohydrodynamic analysis is presented and a computer code developed for prediction of the static and dynamic force response of hydrostatic journal bearings (HJB's), annular seals or damper bearing seals, and fixed arc pad bearings for cryogenic liquid applications. The study includes the most important flow characteristics found in cryogenic fluid film bearings such as flow turbulence, fluid inertia, liquid compressibility and thermal effects. The analysis and computational model devised allow the determination of the flow field in cryogenic fluid film bearings along with the dynamic force coefficients for rotor-bearing stability analysis.

  2. Bear maul craniocerebral trauma in Kashmir Valley.

    Science.gov (United States)

    Bashir, Sheikh Adil; Rasool, Altaf; Zaroo, Mohamad Inam; Wani, Adil Hafeez; Zargar, Haroon Rashid; Darzi, Mohammad Ashraf; Khursheed, Nayil

    2013-01-01

    Craniocerebral injuries constitute the bulk of the trauma patients in all the tertiary-care hospitals. Bear attacks as a cause of trauma to the brain and its protective covering are rare. This was a hospital-based retrospective (January 1990 to July 2005) and prospective study (August 2005 to December 2010). Craniocerebral trauma was seen in 49 patients of bear maul injuries. Loss of scalp tissue was seen in 17 patients, 13 of whom had exposed pericranium and needed split-thickness skin grafting, while 4 patients with exposed skull bones required scalp transposition flaps as an initial procedure. Skull bone fractures without associated brain injury were observed in 24 cases. Frontal bone was the site of fracture in the majority of cases (95%). Surgical intervention was needed in 18 patients for significantly depressed fractures. Three of these patients had depressed frontal bone fractures with underlying contusions and needed brain debridement and duraplasty. Injury to the brain was observed in 8 patients. Trauma to the brain and its protective coverings as a result of bear attacks is rarely known. Brain injury occurs less commonly as compared to soft tissue and bony injury. Craniocerebral trauma as a result of bear assaults has been a hitherto neglected area of trauma as the past reported incidence has been very low. Of late, the incidence and severity of such attacks has assumed grave proportions in areas adjacent to known bear habitats. An innocuous-looking surface wound might be the only presentation of an underlying severe brain trauma. Public awareness has to be generated to protect the people living in hilly areas.

  3. The role of human outdoor recreation in shaping patterns of grizzly bear-black bear co-occurrence.

    Directory of Open Access Journals (Sweden)

    Andrew Ladle

    Full Text Available Species' distributions are influenced by a combination of landscape variables and biotic interactions with other species, including people. Grizzly bears and black bears are sympatric, competing omnivores that also share habitats with human recreationists. By adapting models for multi-species occupancy analysis, we analyzed trail camera data from 192 trail camera locations in and around Jasper National Park, Canada to estimate grizzly bear and black bear occurrence and intensity of trail use. We documented (a occurrence of grizzly bears and black bears relative to habitat variables (b occurrence and intensity of use relative to competing bear species and motorised and non-motorised recreational activity, and (c temporal overlap in activity patterns among the two bear species and recreationists. Grizzly bears were spatially separated from black bears, selecting higher elevations and locations farther from roads. Both species co-occurred with motorised and non-motorised recreation, however, grizzly bears reduced their intensity of use of sites with motorised recreation present. Black bears showed higher temporal activity overlap with recreational activity than grizzly bears, however differences in bear daily activity patterns between sites with and without motorised and non-motorised recreation were not significant. Reduced intensity of use by grizzly bears of sites where motorised recreation was present is a concern given off-road recreation is becoming increasingly popular in North America, and can negatively influence grizzly bear recovery by reducing foraging opportunities near or on trails. Camera traps and multi-species occurrence models offer non-invasive methods for identifying how habitat use by animals changes relative to sympatric species, including humans. These conclusions emphasise the need for integrated land-use planning, access management, and grizzly bear conservation efforts to consider the implications of continued access for

  4. The role of human outdoor recreation in shaping patterns of grizzly bear-black bear co-occurrence.

    Science.gov (United States)

    Ladle, Andrew; Steenweg, Robin; Shepherd, Brenda; Boyce, Mark S

    2018-01-01

    Species' distributions are influenced by a combination of landscape variables and biotic interactions with other species, including people. Grizzly bears and black bears are sympatric, competing omnivores that also share habitats with human recreationists. By adapting models for multi-species occupancy analysis, we analyzed trail camera data from 192 trail camera locations in and around Jasper National Park, Canada to estimate grizzly bear and black bear occurrence and intensity of trail use. We documented (a) occurrence of grizzly bears and black bears relative to habitat variables (b) occurrence and intensity of use relative to competing bear species and motorised and non-motorised recreational activity, and (c) temporal overlap in activity patterns among the two bear species and recreationists. Grizzly bears were spatially separated from black bears, selecting higher elevations and locations farther from roads. Both species co-occurred with motorised and non-motorised recreation, however, grizzly bears reduced their intensity of use of sites with motorised recreation present. Black bears showed higher temporal activity overlap with recreational activity than grizzly bears, however differences in bear daily activity patterns between sites with and without motorised and non-motorised recreation were not significant. Reduced intensity of use by grizzly bears of sites where motorised recreation was present is a concern given off-road recreation is becoming increasingly popular in North America, and can negatively influence grizzly bear recovery by reducing foraging opportunities near or on trails. Camera traps and multi-species occurrence models offer non-invasive methods for identifying how habitat use by animals changes relative to sympatric species, including humans. These conclusions emphasise the need for integrated land-use planning, access management, and grizzly bear conservation efforts to consider the implications of continued access for motorised

  5. Yellowstone grizzly bear investigations: Annual report of the Interagency Grizzly Bear Study Team, 2001

    Science.gov (United States)

    Schwartz, Charles C.; Haroldson, Mark A.

    2001-01-01

    The contents of this Annual Report summarize results of monitoring and research from the 2001 field season. The report also contains a summary of nuisance grizzly bear (Ursus arctos horribilis) management actions.

  6. Yellowstone grizzly bear investigations: Annual report of the Interagency Grizzly Bear Study Team, 2006

    Science.gov (United States)

    Schwartz, Charles C.; Haroldson, Mark A.; West, Karrie K.

    2007-01-01

    The contents of this Annual Report summarize results of monitoring and research from the 2006 field season. The report also contains a summary of nuisance grizzly bear (Ursus arctos horribilis) management actions.

  7. Improvement of Railroad Roller Bearing Test Procedures & Development of Roller Bearing Diagnostic Techniques. Volume 2.

    Science.gov (United States)

    1982-04-01

    A comprehensive review of existing basic diagnostic techniques applicable to the railcar roller bearing defect and failure problem was made. Of the potentially feasible diagnostic techniques identified, high frequency vibration was selected for exper...

  8. Ostracoda and Foraminifera associated with macrofauna of marginal marine origin in continental sabkha sediments of Tayma (NW Saudi Arabia)

    Science.gov (United States)

    Pint, Anna; Frenzel, Peter; Engel, Max; Plessen, Birgit; Melzer, Sandra; Brückner, Helmut

    2016-04-01

    The oasis Tayma in northwestern Saudi Arabia (27°38'N, 38°33'E) is well known for its rich archaeological heritage and also hosts a key sedimentary record of Holocene environmental change.The palaeontologically investigated material comes from two 5.5 m long sediment cores taken in the northeastern and central part of the sabkha and two outcrops of shoreline deposits at the northeastern and southwestern margin of a large lake. Microfossil-rich layers have an age of about 9.2-ca. 8 ka BP. The sandy and carbonate-dominated sediments contain autochthonous balanids, the gastropods Melanoides tuberculatus and hydrobiids as well as the foraminifers Ammonia tepida (Cushman, 1926), Quinqueloculina seminula (Linnaeus, 1758), and Flintionoides labiosa (d'Orbigny, 1839). This brackish water association is completed by partially mass-occurrence of Cyprideis torosa (JONES, 1850), an euryhaline and generally widely tolerant ostracod species. Only the smooth shelled morphotype littoralis occurs. The association indicates a large brackish water lake with temporary freshwater inflows. All species documented originate in the marginal marine environment of the Red or Mediterranean Sea within the intertidal zone and hence they are adapted for strong environmental changes. We assume negative water balance under arid climatic conditions as cause for the high salinity of this athalassic lake. Sieve-pore analyses and shell chemistry suppose a trend of increasing salinity towards the top of the studied microfossil-bearing sections. This pattern is confirmed by increasing test malformation ratios of foraminifers. The marine origin of the fauna is surprising in this area 250 km away from the sea in an altitude of about 800 m a.s.l. We assume an avian-mediated transport of eggs, larvae or even adult animals to this site. The brackish water character of the lake enabled a permanent settling of marginal marine foraminifers, ostracods and even macrofauna as gastropods and balanids. The studied

  9. The thermodynamic properties of a new type catcher bearing used in active magnetic bearings system

    International Nuclear Information System (INIS)

    Jin, Chaowu; Zhu, Yili; Xu, Longxiang; Xu, Yuanping; Zheng, Yantong

    2015-01-01

    Normally a rotor levitated by active magnetic bearings (AMBs) system would rotate without contacting with any stator component, but the possibility still remains that the supporting force might lose temporarily or permanently, thus requiring the Catcher bearings (CBs) to provide backup protection in case of the failure of AMBs. A new type CB with two separate rolling element bearing series could have the speed distribution between the inner race and intermediate race according to certain ratio, in which the speed of each roller element bearing decreases with the limit speed of the whole CB increasing, offering high capability to sustain its initial rotation speed. Based on the theory of heat transfer, tribology, and rotor dynamics, this paper analyzes the thermal structure of double-decker catcher bearing (DDCB) and single-decker catcher bearing (SDCB), respectively. Through this structure, the thermal resistances and equations of heat transfer can be obtained. Then we calculate the friction heat and temperature distribution in the various CBs upon rotor's dropping on SDCB or DDCB, followed by the discussion on the CBs temperature rise's effects on lubrication conditions and rotor dynamics parameters. Finally various experiments are carried out to measure the temperature rise of different CBs. The results obtained validate the theoretical analysis and also provide main methods to reduce heat generation. Using DDCB is proved to be effective to reduce the temperature rise. - Highlights: • The DDCB is a more suitable catcher bearing for AMBs. • Compared to SDCB, using DDCB, the temperature rise can decrease in the same states. • A lower viscosity of lubricant may induce a lower temperature rise. • The inner raceway temperature of the first layer bearing is the highest. • Reducing the unbalance mass of the rotor is a method to decrease the temperature rise

  10. Local Attitudes towards Bear Management after Illegal Feeding and Problem Bear Activity

    OpenAIRE

    David Fraser; Sara Dubois

    2013-01-01

    Simple Summary The “pot bears” received international media attention in 2010 after police discovered the intentional feeding of black bears during the investigation of an alleged marijuana-growing operation in Christina Lake, British Columbia. Residents of this small community were surveyed by phone twice over the following year, before and after government actions. This study aimed to understand local attitudes on how these bears should be managed and whether they differed from existing bea...

  11. Reduced Bearing Excursion After Mobile-Bearing Unicompartmental Knee Arthroplasty is Associated With Poor Functional Outcomes.

    Science.gov (United States)

    Wahal, Naman; Gaba, Sahil; Malhotra, Rajesh; Kumar, Vijay; Pegg, Elise C; Pandit, Hemant

    2018-02-01

    A small proportion of patients with mobile unicompartmental knee arthroplasty (UKA) report poor functional outcomes in spite of optimal component alignment on postoperative radiographs. The purpose of this study is to assess whether there is a correlation between functional outcome and knee kinematics. From a cohort of consecutive cases of 150 Oxford medial UKA, patients with fair/poor functional outcome at 1-year postsurgery (Oxford Knee Score [OKS] bearing position with knee flexion angle. Mean OKS in the fair/poor group was 29.9 and the mean OKS in the good/excellent group was 41.1. The tibial slope, time taken to complete the exercises, and patellar tendon angle trend over the flexion range were similar in both the groups; however, bearing position and the extent of bearing excursion differed significantly. The total bearing excursion in the OKS bearing was positioned 1.7 mm more posterior on the tibia in the OKS bearing excursion and positioning, are associated with worse functional outcomes after mobile UKA. Copyright © 2017 Elsevier Inc. All rights reserved.

  12. Monitoring of lubrication conditions in journal bearing by acoustic emission

    International Nuclear Information System (INIS)

    Yoon, Dong Jin; Kwon, Oh Yang; Jung, Min Hwa

    1993-01-01

    Systems with journal bearings generally operate in large scale and under severe loading conditions such as steam generator turbines and internal combustion engines, in contrast to the machinery using rolling element bearings. Failure of the bearings in these machinery can result in the system breakdown. To avoid the time consuming repair and considerable economic loss, the detection of incipient failure in journal bearings becomes very important. In this experimental approach, acoustic emission monitoring is employed to the detection of incipient failure caused by intervention of foreign particles most probable in the journal bearing systems. It has been known that the intervention of foreign materials, insufficient lubrication and misassembly etc. are principal factors to cause bearing failure and distress. The experiment was conducted under such designed conditions as inserting alumina particles to the lubrication layer in the simulated journal bearing system. The results showed that acoustic emission could be an effective tool to detect the incipient failure in journal bearings.

  13. Trichinella and polar bears: a limited risk for humans.

    Science.gov (United States)

    Dupouy-Camet, J; Bourée, P; Yera, H

    2017-07-01

    In this review, we identified 63 cases reported since World War II of human trichinellosis linked to the consumption of parasitized polar bear (Ursus maritimus) meat. This low number contrasts to the numerous cases of human trichinellosis related to consumption of the meat of black (U. americanus) or brown bears (U. arctos). The prevalence of Trichinella infection is high in bears, but larval muscular burden is usually lower in polar bears compared to other bear species. Polar bears, therefore, seem to play a limited role in the transmission of trichinellosis to humans, as native residents living in the Arctic traditionally consume well-cooked bear meat, and travellers and foreign hunters have only limited access to this protected species due to the declining polar bear population.

  14. Nuclear fuel handling grapple carriage with self-lubricating bearing

    International Nuclear Information System (INIS)

    1977-01-01

    This invention relates to the provision of a fuel handling grapple carriage for a sodium cooled fast breeder reactor with sodium coolant lubricated bearings in which contamination of the bearings is prevented. (UK)

  15. Fatigue life of drilling bit bearings under arbitrary random loads

    Energy Technology Data Exchange (ETDEWEB)

    Talimi, M.; Farshidi, R. [Calgary Univ., AB (Canada)

    2009-07-01

    A fatigue analysis was conducted in order to estimate the bearing life of a roller cone rock bit under arbitrary random loads. The aim of the study was to reduce bearing failures that can interrupt well operations. Fatigue was considered as the main reason for bearing failure. The expected value of cumulative fatigue damage was used to estimate bearing life. An equation was used to express the relation between bearing life and bearing load when the bearing was subjected to a steady load and constant speed. The Palmgren-Miner hypothesis was used to determine the ultimate tensile strength of the material. The rain flow counting principle was used to determine distinct amplitude cycles. Hertzian equations were used to determine maximum stress loads. Fourier series were used to obtain simple harmonic functions for estimating stress-life relations. It was concluded that the method can be used during the well planning phase to prevent bearing failures. 6 refs.

  16. Modeling of Hybrid Permanent Magnetic-Gas Bearings

    DEFF Research Database (Denmark)

    Morosi, Stefano; Santos, Ilmar

    2009-01-01

    Modern turbomachinery applications require nowadays ever-growing rotational speeds and high degree of reliability. It then becomes natural to focus the attention of the research to contact-free bearings elements. The present alternatives focus on gas lubricated journal bearings or magnetic bearings....... In the present paper, a detailed mathematical modeling of the gas bearing based on the compressible form of the Reynolds equation is presented. Perturbation theory is applied in order to identify the dynamic characteristic of the bearing. Due to the simple design of the magnetic bearings elements - being...... the rotor equilibrium position can be made independent on the rotational speed and applied load; it becomes function of the passive magnetic bearing offset. By adjusting the offset it is possible to significantly influence the dynamic coefficients of the hybrid bearing....

  17. Experimental Study and Dynamic Modeling of Metal Rubber Isolating Bearing

    International Nuclear Information System (INIS)

    Zhang, Ke; Zhou, Yanguo; Jiang, Jian

    2015-01-01

    In this paper, dynamic shear mechanical properties of a new metal rubber isolating bearing is tested and studied. The mixed damping model is provided for theoretical modeling of MR isolating bearing, the shear stiffness and damping characteristics of the MR bearing can be analyzed separately and easily discussed, and the mixed damping model is proved to be an rather effective approach. The test results indicate that loading frequency bears little impact over shear property of metal rubber isolating bearing, the total energy consumption of metal rubber isolating bearing increases with the increase in loading amplitude. With the increase in loading amplitude, the stiffness of the isolating bearing will reduce showing its “soft property”; and the type of damping force gradually changes to be close to dry friction. The features of “soft property” and dry friction energy consumption of metal rubber isolating bearing are very useful in practical engineering application. (paper)

  18. Blade Bearing Friction Estimation of Operating Wind Turbines

    DEFF Research Database (Denmark)

    Perisic, Nevena; Pedersen, Bo Juul; Kirkegaard, Poul Henning

    2012-01-01

    Blade root bearing on a wind turbine (WTG) enables pitching of blades for power control and rotor braking and is a WTG critical component. As the size of modern WTGs is constantly increasing, this leads to relatively less rigid bearings, more sensitive to deformations, thus WTG operational...... reliability can be increased by continuous monitoring of blade bearing. High blade bearing friction is undesirable, as it may be associated with excessive heating of the surfaces, damage and/or inefficient operation. Thus, continuous observation of bearing friction level is crucial for blade bearing health...... monitoring systems. A novel algorithm for online monitoring of bearing friction level is developed combining physical knowledge about pitch system dynamics with state estimator, i.e. observer theory and signal processing assuming realistic sensor availability. Results show estimation of bearing friction...

  19. Self-Bearing Motor-Generator for Flywheels, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — Self-bearing or ?bearingless? motors perform both motor and bearing support functions but such devices have not yet achieved speeds above 15,000 rpm. The innovation...

  20. Evaluation of ball and roller bearings restored by grinding

    Science.gov (United States)

    Parker, R. J.; Zaretsky, E. V.; Chen, S. M.

    1976-01-01

    A joint program was undertaken to restore by grinding those rolling-element bearings which are currently being discarded at aircraft engine and transmission overhaul. Three bearing types were selected from the UH-1 helicopter engine (T-53) and transmission for the pilot program. Groups of each of these bearings were visually and dimensionally inspected for suitability for restoration. A total of 250 bearings were restored by grinding. Of this number, 30 bearings from each type were endurance tested to a TBO of 1600 hours. No bearing failures occurred related to the restoration by grinding process. The two bearing failures which occurred were due to defective rolling elements and were typical of those which may occur in new bearings. The restorable component yield to the three groups was in excess of 90 percent.

  1. Reporting underage consensual sex after the Teddy Bear case: A ...

    African Journals Online (AJOL)

    recent Teddy Bear Clinic for Abused Children, and Resources Aimed at the. Prevention of ... Act until the Constitutional Court confirms the judgement of the. Teddy Bear ... an obligation on all service providers, including doctors, nurses and.

  2. Modeling of dynamically loaded hydrodynamic bearings at low Sommerfeld numbers

    DEFF Research Database (Denmark)

    Thomsen, Kim

    Current state of the art within the wind industry dictates the use of conventional rolling element bearings for main bearings. As wind turbine generators increase in size and output, so does the size of the main bearings and accordingly also the cost and potential risk of failure modes. The cost...... and failure risk of rolling element bearings do, however, grow exponentially with the size. Therefore hydrodynamic bearings can prove to be a competitive alternative to the current practice of rolling element bearings and ultimately help reducing the cost and carbon footprint of renewable energy generation....... The challenging main bearing operation conditions in a wind turbine pose a demanding development task for the design of a hydrodynamic bearing. In general these conditions include operation at low Reynolds numbers with frequent start and stop at high loads as well as difficult operating conditions dictated...

  3. Stepping-Motion Motor-Control Subsystem For Testing Bearings

    Science.gov (United States)

    Powers, Charles E.

    1992-01-01

    Control subsystem closed-loop angular-position-control system causing motor and bearing under test to undergo any of variety of continuous or stepping motions. Also used to test bearing-and-motor assemblies, motors, angular-position sensors including rotating shafts, and like. Monitoring subsystem gathers data used to evaluate performance of bearing or other article under test. Monitoring subsystem described in article, "Monitoring Subsystem For Testing Bearings" (GSC-13432).

  4. Static Load Distribution in Ball Bearings

    Science.gov (United States)

    Ricci, Mario

    2010-01-01

    A numerical procedure for computing the internal loading distribution in statically loaded, single-row, angular-contact ball bearings when subjected to a known combined radial and thrust load is presented. The combined radial and thrust load must be applied in order to avoid tilting between inner and outer rings. The numerical procedure requires the iterative solution of Z + 2 simultaneous nonlinear equations - where Z is the number of the balls - to yield an exact solution for axial and radial deflections, and contact angles. Numerical results for a 218 angular-contact ball bearing have been compared with those from the literature and show significant differences in the magnitudes of the ball loads, contact angles, and the extent of the loading zone.

  5. An Evershed type superconducting flywheel bearing

    Energy Technology Data Exchange (ETDEWEB)

    Cansiz, A.; Campbell, A.M.; Coombs, T.A

    2003-07-15

    The objective of this work is to develop a bearing using high temperature superconductors (HTSs) for use in an energy storage flywheel. The experimental apparatus includes a cylindrical rotor levitated with the Evershed design in which the majority of the levitation force is provided by a permanent magnet arrangement and the stabilization of the system is achieved by HTS elements. The design characteristics and dynamics of the bearing associated with the rotor part are presented. The instrumentation measures the out of balance force and magnetomechanical stiffness associated with the rotor. A study of the rotational losses was performed using free spin down experiments associated with magnetic field variation measurements. The results are consistent with the loss being caused by hysteresis in the superconductor due to magnet inhomogeneity.

  6. Radioactivity and the French uranium bearing minerals

    International Nuclear Information System (INIS)

    Guiollard, P.Ch.; Boisson, J.M.; Leydet, J.C.; Meisser, N.

    1998-01-01

    This special issue of Regne Mineral journal is entirely devoted to the French uranium mining industry. It comprises 4 parts dealing with: the uranium mining industry in France (history, uranium rush, deposits, geologic setting, prosperity and recession, situation in 1998, ore processing); radioactivity and the uranium and its descendants (discovery, first French uranium bearing ores, discovery of radioactivity, radium and other uranium descendants, radium mines, uranium mines, atoms, elements and isotopes, uranium genesis, uranium decay, isotopes in an uranium ore, spontaneous fission, selective migration of radionuclides, radon in mines and houses, radioactivity units, radioprotection standards, new standards and controversies, natural and artificial radioactivity, hazards linked with the handling and collecting of uranium ores, conformability with radioprotection standards, radioactivity of natural uranium minerals); the French uranium bearing minerals (composition, crystal structure, reference, etymology, fluorescence). (J.S.)

  7. Bearing Assembly With Carbonate Resistant Anti-Seizing Properties

    Science.gov (United States)

    2014-01-28

    surface. Dkt . No. 101805 Application No. ?? REPLACEMENT SHEET? /21 LINEAR MOVEMENT ROTATIONAL MOVEMENT BEARING SURFACE ROTOR OR SLIDER BEARING ROTOR...OR SLIDER BEARING SHAFT FIG. 1 (PRIOR ART) FIG. 2 (PRIOR ART) Dkt . No. 101805 Application No. ?? REPLACEMENT SHEET? /22 100 110 112 114 120 118 116 120 118 114 112 110 LINEAR MOVEMENT ROTATIONAL MOVEMENT 100 FIG. 3 FIG. 4

  8. Marking behavior of Andean bears in an Ecuadorian cloud forest

    NARCIS (Netherlands)

    Filipczyková, Eva; Heitkonig, Ignas; Castellanos, Armando; Hantson, Wouter; Steyaert, Sam M.J.G.

    2017-01-01

    Very little is known about marking behavior of the endangered Andean bear (Tremarctos ornatus). Here, we present a first detailed description of Andean bear marking behavior obtained using camera traps. From November 2012 to April 2013, we inspected 16 bear trails in the Napo province of eastern

  9. The Imagined Bear | Bieder | Current Writing: Text and Reception in ...

    African Journals Online (AJOL)

    This spiritual power was often articulated through stories such as those presented here where bears are portrayed as powerful sacred spirits; as ancestors, healers, shape-shifters, lovers and mates. The stories, however, are not just about bears; the stories are also about cultures and how peoplo saw themselves in bears ...

  10. 49 CFR 230.103 - Tender roller bearing journal boxes.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Tender roller bearing journal boxes. 230.103... Locomotives and Tenders Running Gear § 230.103 Tender roller bearing journal boxes. Tender roller bearing journal boxes shall be maintained in a safe and suitable condition. ...

  11. 77 FR 5201 - Drawbridge Operation Regulation; Bear Creek, Dundalk, MD

    Science.gov (United States)

    2012-02-02

    ...-AA09 Drawbridge Operation Regulation; Bear Creek, Dundalk, MD AGENCY: Coast Guard, DHS. ACTION: Notice... operation of the Baltimore County highway bridge at Wise Avenue across Bear Creek, mile 3.4, between Dundalk... Avenue across Bear Creek, mile 3.4 between Dundalk and Sparrows Point, MD. This change would require the...

  12. Trichinella surveillance in black bears (Ursus americanus) from Oregon, USA.

    Science.gov (United States)

    Mortenson, J A; Kent, M L; Fowler, D R; Chomel, B B; Immell, D A

    2014-01-01

    We used serology and muscle digestion to test black bears (Ursus americanus) from western Oregon, USA, for Trichinella. Results indicate black bears in Oregon are not part of a sylvatic cycle for Trichinella, and risk of human exposure to Trichinella larvae from eating black bear meat from Oregon appears low.

  13. Oak-Black Bear Relationships in Southeastern Uplands

    Science.gov (United States)

    Joseph D. Clark

    2004-01-01

    Bears (Ursus americanus) primarily occur in upland habitats in the Southeast because uplands were the last to be developed for agriculture and were more likely to become publicly owned. National parks and forests created in the early to mid-1900s served as sources to supply surrounding uplands with bears. Bears could not survive in southeastern...

  14. Superconducting Meissner effect bearings for cryogenic turbomachines, phase 2

    Science.gov (United States)

    Valenzuela, Javier A.; Martin, Jerry L.

    1994-02-01

    This is the final report of a Phase 2 SBIR project to develop Meissner effect bearings for miniature cryogenic turbomachines. The bearing system was designed for use in miniature cryogenic turboexpanders in reverse-Brayton-cycle cryocoolers. The cryocoolers are designed to cool sensors on satellites. Existing gas bearings for this application run in a relatively warm state. The heat loss from the bearings into the shaft and into the cold process gas imposes a penalty on the cycle efficiency. By using cold Meissner effect bearings, this heat loss could be minimized, and the input power per unit of cooling for these cryocoolers could be reduced. Two bearing concepts were explored in this project. The first used an all-magnetic passive radial suspension to position the shaft over a range of temperatures from room temperature to 77 K. This bearing concept was proven to be feasible, but impractical for the miniature high-speed turbine application since it lacked the required shaft positioning accuracy. A second bearing concept was then developed. In this concept, the Meissner effect bearings are combined with self-acting gas bearings. The Meissner effect bearing provides the additional stiffness and damping required to stabilize the shaft at low temperature, while the gas bearing provides the necessary accuracy to allow very small turbine tip clearances (5mm) and high speeds (greater than 500,000 rpm).

  15. Mechanical design problems associated with turbopump fluid film bearings

    Science.gov (United States)

    Evces, Charles R.

    1990-01-01

    Most high speed cryogenic turbopumps for liquid propulsion rocket engines currently use ball or roller contact bearings for rotor support. The operating speeds, loads, clearances, and environments of these pumps combine to make bearing wear a limiting factor on turbopump life. An example is the high pressure oxygen turbopump (HPOTP) used in the Space Shuttle Main Engine (SSME). Although the HPOTP design life is 27,000 seconds at 30,000 rpms, or approximately 50 missions, bearings must currently be replaced after 2 missions. One solution to the bearing wear problem in the HPOTP, as well as in future turbopump designs, is the utilization of fluid film bearings in lieu of continuous contact bearings. Hydrostatic, hydrodynamic, and damping seal bearings are all replacement candidates for contact bearings in rocket engine high speed turbomachinery. These three types of fluid film bearings have different operating characteristics, but they share a common set of mechanical design opportunities and difficulties. Results of research to define some of the mechanical design issues are given. Problems considered include transient strat/stop rub, non-operational rotor support, bearing wear inspection and measurement, and bearing fluid supply route. Emphasis is given to the HPOTP preburner pump (PBP) bearing, but the results are pertinent to high-speed cryogenic turbomachinery in general.

  16. PROVIDING SERVICEABILITY OF STRUCTURAL BEARING TYPES FOR ROADWAY BRIDGES

    Directory of Open Access Journals (Sweden)

    R. I. Polyuga

    2010-03-01

    Full Text Available In the article the description of structural bearing types for roadway bridges and their classification is given. Special attention is paid to effective bearings with elastomeric materials – rubber, pot, spherical ones. Characteristic defects of structural bearings and demands of serviceability are noticed.

  17. 7 CFR 761.53 - Interest bearing accounts.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 7 2010-01-01 2010-01-01 false Interest bearing accounts. 761.53 Section 761.53... AGRICULTURE SPECIAL PROGRAMS GENERAL PROGRAM ADMINISTRATION Supervised Bank Accounts § 761.53 Interest bearing accounts. (a) A supervised bank account, if possible, will be established as an interest bearing deposit...

  18. 49 CFR 215.111 - Defective plain bearing.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Defective plain bearing. 215.111 Section 215.111... § 215.111 Defective plain bearing. A railroad may not place or continue in service a car, if the car has a plain bearing— (a) That is missing, cracked, or broken; (b) On which the bearing liner— (1) Is...

  19. Modelling and simulation of a compliant tilting pad air bearing

    NARCIS (Netherlands)

    Duijnhouwer, F.; Nijmeijer, H.

    The compliant tilting pad air bearing concept, a tilting pad bearing with the pivot of the pads placed on radial springs, is a promising aerodynamic bearing solution. Nevertheless, its non-linear dynamics make a time domain dynamic simulation model an essential tool for the design of rotor systems

  20. 49 CFR 215.113 - Defective plain bearing wedge.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Defective plain bearing wedge. 215.113 Section 215... Suspension System § 215.113 Defective plain bearing wedge. A railroad may not place or continue in service a car, if a plain bearing wedge on that car is— (a) Missing; (b) Cracked; (c) Broken; or (d) Not located...