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Sample records for acid leakage hypothesis

  1. Evaluating the Silicic Acid Leakage Hypothesis in the Pacific Sector of the Southern Ocean

    NASA Astrophysics Data System (ADS)

    Wall, A.; Baldwin, M.; Burckle, L.; Anderson, R.

    2004-12-01

    The Silicic Acid Leakage Hypothesis (SALH; Matsumoto et al., 2002; Glob. Biogeochem. Cycles 16, 10.1029/2001GB001442) posits that lower atmospheric carbon dioxide concentrations during glacial times resulted from a net transfer of dissolved silicic acid from the Southern Ocean to the tropics, coupled with a corresponding shift in phytoplankton taxa in tropical waters toward a greater dominance by diatoms (relative to today). If valid, then the SALH requires that opal burial rates in the Southern Ocean were lower than today during the Last Glacial Maximum (LGM), while contemporary opal burial rates in tropical regions were greater than today. Previous studies in the Indian and Atlantic sectors of the Southern Ocean have shown little to no net change between the LGM and the Holocene when opal burial rates are integrated across Subantarctic and Antarctic zones. This study aims to test a sub-hypothesis suggested by Chase et al. (Deep-Sea Research-II, v.50, 2003, 799-832) that silicic acid was exported only out of the Pacific sector. Piston cores from the SW Pacific sector of the Southern Ocean were analyzed to determine opal burial fluxes. Magnetic susceptibility and Eucampia antarctica abundances were used to determine glacial cycles and identify cores containing both LGM and Holocene sediment. Fluxes of opal, calcium carbonate, and lithogenic material were evaluated by normalizing to 230Th to correct for sediment focusing. Our results show opal flux at, and to the south of, the Antarctic Polar Front (APF) to have been lower during the LGM compared to the Holocene, consistent with previous results from throughout the Southern Ocean. North of the APF, two cores show higher opal fluxes during the LGM. However, due to a possible hiatus in one of the cores, the degree to which opal flux during the LGM was greater than during the Holocene has a large uncertainty. Additional analyses are planned to help reduce this uncertainty.

  2. Colorimetric determination of phosphoric acid leakage for phosphoric acid-doped polybenzimidazole membrane fuel cell applications

    NASA Astrophysics Data System (ADS)

    Jeong, Yeon Hun; Jung, Ju Hae; Choi, Euiji; Han, Seungyoon; Begley, Alina Irene; Yoo, Sung Jong; Jang, Jong Hyun; Kim, Hyoung-Juhn; Nam, Suk Woo; Lee, Kwan-Young; Kim, Jin Young

    2015-12-01

    A simple and precise colorimetric method for analyzing phosphoric acid leakage in phosphoric acid-doped polybenzimidazole membrane fuel cells is described. The developed method is based on the colorimetric determination from a rapid formation of molybdenum blue color by the reduction reaction of molybdate ions in the presence of phosphoric acid in the acidic medium. The color is stable up to a few months and can be used for the sensitive and accurate detection of phosphoric acid electrolyte which is discharged from the fuel cell during operation. Tests with a wide concentration range of phosphate compounds showed that it permits determination of phosphoric acid up to nanogram quantities. The developed detection method assists monitoring the phosphoric acid contents and developing stable operation strategies of fuel cells.

  3. Essential fatty acids and sleep: mini-review and hypothesis.

    PubMed

    Yehuda, S; Rabinovitz, S; Mostofsky, D I

    1998-02-01

    The neurochemical basis of sleep mechanisms (onset and maintenance) is still controversial although the phenomenon itself is known to be mediated by more than a single molecule. The list of suggested endogenous sleep substances is rather long, and there is no single 'sleep center' identified in the brain. The role of fatty acids, and essential fatty acids in particular, has been ignored in sleep research. This review proposes an integration of the current knowledge about the effects of fatty acids in sleep neurochemistry, wherein fatty acids are seen to exert a direct effect on neuronal membrane structure or indirectly on the dynamics of biochemical compounds (complex lipids, prostaglandins, neurotransmitters, amino acids, interleukins) necessary for the initiation and maintenance of sleep.

  4. Evidence that prolonged histamine suffusions produce transient increases in vascular permeability subsequent to the formation of venular macromolecular leakage sites. Proof of the Majno-Palade hypothesis.

    PubMed Central

    Horan, K. L.; Adamski, S. W.; Ayele, W.; Langone, J. J.; Grega, G. J.

    1986-01-01

    The aim of this study was to determine whether histamine-stimulated increases in macromolecular efflux are dependent on the formation of specific vascular leakage sites, or whether other mechanisms need to be invoked to explain the increase in macromolecular efflux produced by this inflammatory mediator. Intravital light microscopy was used to localize and quantitate vascular macromolecular leakage sites in the noneverted hamster cheek pouch. Fluorimetric measurements of plasma and suffusate tracer (FITC-D 70,000 mol wt) concentrations were utilized to quantitate changes in macromolecular efflux. In some experiments, the FITC-D was injected intravenously either at the start of or after the start of a prolonged histamine suffusion for estimation of the duration of the vascular FITC-D leakage response. In saline control cheek pouches there were few, if any, visible FITC-D vascular leakage sites and only small increases in the [FITC-D]s. The arteriolar vasodilators papaverine (1 X 10(-5) M) and isoproterenol (1 X 10(-5) M) failed to increase the formation of vascular FITC-D leakage sites, and the magnitude of the increase in [FITC-D]s produced by these agents was similar to that observed in saline controls. Histamine (1 X 10(-5) M) suffused for either 15, 60, or 120 minutes produced marked increases in [FITC-D]s and in the number of venular FITC-D leakage sites. The venular FITC-D leakage sites began to fade after 10-20 minutes, eventually disappearing altogether. In contrast, the [FITC-D]s was markedly increased throughout the 120-minute observation period. Treatment with papaverine prior to and during the 60-minute histamine suffusion failed to prevent the mediator-stimulated vascular leakage response. In contrast, similar treatment with isoproterenol inhibited the histamine-stimulated increases in [FITC-D]s and the formation of venular FITC-D leakage sites. When the tracer was injected intravenously at the start of the 60-minute histamine suffusion (1 X 10(-5) M

  5. Experimentally Testing the Hypothesis of a Limited Amino Acid Repertoire in Primitive Proteins

    NASA Astrophysics Data System (ADS)

    Akanuma, S.; Nakajima, Y.; Yokobori, S.; Yamagishi, A.

    2013-11-01

    It has been argued that a fewer amino acids were used in primitive proteins and later the repertoire increased up to 20. To test this hypothesis experimentally, we restricted the amino acid usage of a reconstructed, ancestral protein to reduced sets.

  6. Combined inhalational and oral supplementation of ascorbic acid may prevent influenza pandemic emergency: a hypothesis.

    PubMed

    Banerjee, Dibyajyoti; Kaul, Deepak

    2010-01-01

    Occurrence of influenza pandemics is a worldwide phenomenon and a significant cause of mortality and morbidity throughout the globe. It is due to mutations in the influenza virus genetic material creating antigenic drift of pathogenic viral proteins resulting in emergence of new influenza virus strains. Therefore, the vaccines available for prevention of influenza offer no protection against influenza pandemics caused by new virus strains. Moreover, the existing drugs used to combat influenza may be ineffective to treat influenza pandemics due to the emergence of drug resistance in the pandemic virus strain. Therefore, a working strategy must be developed to combat influenza pandemics. In this review we have addressed this problem and reviewed the published studies on ascorbic acid in the common cold and influenza and laboratory studies on the effect of ascorbic acid on influenza virus. We have also correlated the clinical and laboratory studies and developed a hypothesis to prevent influenza pandemics. PMID:20005468

  7. Experimental test of the superheavy fission hypothesis in acid residues from the allende meteorite

    SciTech Connect

    Flynn, G.J.

    1982-01-01

    A description of a series of experiments to find evidence to confirm or contradict the hypothesis that isotopically anomalous Xe (called CCF-Xe) in carbonaceous chondrite meteorites results from the fission decay of a superheavy element is given. The first two experiments were searches for fossil evidence - fission tracks and isotopic anomalies - of superheavy fission decay in the Allende carbonaceous chondrite. It was demonstrated that chromite, a mineral rich in CCF-Xe, records fission tracks, and a search for such tracks in Allende chromite was performed with negative results. It was also demonstrated in certain CCF-XE rich phases of Allende, isotopic anomalies like those seen in Xe should be detectable in Ba and the light rare earths. Preliminary results from a collaborative measurement (with the University of Paris) show the Ba isotopic ratios to be normal in a CCF-Xe rich Allende sample. The third experiment was motivated by reports of the detection of a live, fissioning superheavy element, using a neutron counting technique, in bulk Allende (Flerov, 1978). Since almost all of the allegedly fissiogenic Xe in Allende is concentrated in certain acid insoluble phases, we developed a technique to detect low-level fission activity in these phases. Allende acid insoluble residue (provided by the University of Chicago) was dispersed in a 1 mg/cm/sup 2/ layer, between two track recording detectors. An automatic track locating system was developed to allow large detector areas to be scanned for rate fission events.

  8. Role of nicotinic acid and nicotinamide in nicorandil-induced ulcerations: from hypothesis to demonstration.

    PubMed

    Trechot, Philippe; Jouzeau, Jean-Yves; Brouillard, Clotilde; Scala-Bertola, Julien; Petitpain, Nadine; Cuny, Jean-François; Gauchotte, Guillaume; Schmutz, Jean-Luc; Barbaud, Annick

    2015-10-01

    Nicorandil, a nicotinamide ester, was first reported to be involved in the induction of oral ulcers in 1997. Since then, many reports of single or multiple nicorandil-induced ulcerations (NIUs) have been reported. We hypothesised that in the case of high-dosage nicorandil or after an increased dosage of nicorandil, nicotinic acid and nicotinamide (two main metabolites of nicorandil) cannot appropriately merge into the endogenous pool of nicotinamide adenine dinucleotide/phosphate, which leads to abnormal distribution of these metabolites in the body. In recent or maintained trauma, nicotinamide increases blood flow at the edge of the raw area, inducing epithelial proliferation, while nicotinic acid ulcerates this epithelial formation, ultimately flooding the entire scar. We demonstrate, by comparison to a control patient non-exposed to nicorandil, an abnormal amount of nicotinic acid (×38) and nicotinamide (×11) in the ulcerated area in a patient with NIUs. All practitioners, especially geriatricians, dermatologists and surgeons, must be aware of these serious and insidious side effects of nicorandil. It is critical to rapidly reassess the risk-benefit ratio of this drug for any patient, and not only for those with diverticular diseases.

  9. Role of nicotinic acid and nicotinamide in nicorandil-induced ulcerations: from hypothesis to demonstration.

    PubMed

    Trechot, Philippe; Jouzeau, Jean-Yves; Brouillard, Clotilde; Scala-Bertola, Julien; Petitpain, Nadine; Cuny, Jean-François; Gauchotte, Guillaume; Schmutz, Jean-Luc; Barbaud, Annick

    2015-10-01

    Nicorandil, a nicotinamide ester, was first reported to be involved in the induction of oral ulcers in 1997. Since then, many reports of single or multiple nicorandil-induced ulcerations (NIUs) have been reported. We hypothesised that in the case of high-dosage nicorandil or after an increased dosage of nicorandil, nicotinic acid and nicotinamide (two main metabolites of nicorandil) cannot appropriately merge into the endogenous pool of nicotinamide adenine dinucleotide/phosphate, which leads to abnormal distribution of these metabolites in the body. In recent or maintained trauma, nicotinamide increases blood flow at the edge of the raw area, inducing epithelial proliferation, while nicotinic acid ulcerates this epithelial formation, ultimately flooding the entire scar. We demonstrate, by comparison to a control patient non-exposed to nicorandil, an abnormal amount of nicotinic acid (×38) and nicotinamide (×11) in the ulcerated area in a patient with NIUs. All practitioners, especially geriatricians, dermatologists and surgeons, must be aware of these serious and insidious side effects of nicorandil. It is critical to rapidly reassess the risk-benefit ratio of this drug for any patient, and not only for those with diverticular diseases. PMID:24028540

  10. Analyzing Leakage Through Cracks

    NASA Technical Reports Server (NTRS)

    Romine, William D.

    1993-01-01

    Two related computer programs written for use in analyzing leakage through cracks. Leakage flow laminar or turbulent. One program used to determine dimensions of crack under given flow conditions and given measured rate of leakage. Other used to determine rate of leakage of gas through crack of given dimensions under given flow conditions. Programs, written in BASIC language, accelerate and facilitate iterative calculations and parametric analyses. Solve equations of Fanno flow. Enables rapid solution of leakage problem.

  11. Hypothesis: Nitro-fatty acids play a role in plant metabolism.

    PubMed

    Sánchez-Calvo, Beatriz; Barroso, Juan B; Corpas, Francisco J

    2013-02-01

    The free radical molecule nitric oxide (NO) is involved in a wide range of plant functions such as growth, senescence, fruit ripening, and responses to adverse environmental conditions. NO and NO-derived molecules peroxynitrite and S-nitrosoglutathione are reactive nitrogen species (RNS) that can directly or indirectly interact with a broad spectrum of biomolecules that affect their biological functions. Plant NO research has focused on post-translational modifications in proteins, mainly S-nitrosylation and nitration. There are other potential target biomolecules in plants that have not been studied, which have been studied in animal systems, such as lipids. Nitro-fatty acids (NO(2)-FAs) are involved in pleiotropic activities in animal systems, including modulation of macrophage activation, prevention of leukocyte and platelet activation, and promotion of blood vessel relaxation. NO(2)-FAs are therefore novel mediators in NO signaling pathways and metabolism. This review will focus on these molecules and will highlight their potential in relation to the physiology of higher plants.

  12. Salvianolic Acid B Ameliorates Lipopolysaccharide-Induced Albumin Leakage from Rat Mesenteric Venules through Src-Regulated Transcelluar Pathway and Paracellular Pathway

    PubMed Central

    Liu, Yu-Ying; Zhang, Yu; He, Ke; Yang, Xiao-Yuan; Hu, Bai-He; Chang, Xin; Wang, Ming-Xia; Wei, Xiao-Hong; Fan, Jing-Yu; Wu, Xin-Min; Han, Jing-Yan

    2015-01-01

    Lipopolysaccharide (LPS) causes microvascular barrier disruption, leading to albumin leakage from microvessels resulting in a range of disastrous sequels. Salvianolic acid B (SalB) is a major water-soluble component derived from Salvia miltiorrhiza. Previous studies showed its potential to attenuate microvascular barrier dysfunction, but the underlying mechanism is not fully understood. The present study was intended to investigate the impact of SalB on endothelial cell barrier in vivo in rat mesenteric venules as well as in vitro in human umbilical vein endothelial cells (HUVECs), aiming at disclosing the mechanism thereof, particularly the role of Src in its action. Male Wistar rats were challenged by infusion of LPS (2 mg/kg/h) through left femoral vein for 90 min. SalB (5 mg/kg/h) was administrated either simultaneously with LPS or 30 min after LPS infusion through the left jugular vein. Vesicles in venular walls were observed by electron microscopy. HUVECs were incubated with LPS with or without SalB. The expression of Zonula occluden-1 (ZO-1), VE-cadherin, caveolin-1 and Src in HUVECs was assessed by Western blot and confocal microscopy, binding of SalB to Src was measured using Surface Plasmon Resonance and BioLayer Interferometry. Treatment with SalB inhibited albumin leakage from rat mesenteric venules and inhibited the increase of vesicle number in venular endothelial cells induced by LPS. In addition, SalB inhibited the degradation of ZO-1, the phosphorylation and redistribution of VE-cadherin, the expression and phosphorylation of caveolin-1, and phosphoirylation of Src in HUVECs exposed to LPS. Furthermore, SalB was found able to bind to Src. This study demonstrates that protection of SalB against microvascular barrier disruption is a process involving both para- and trans-endothelial cell pathway, and highly suggests Src as the key enzyme for SalB to work. PMID:25992563

  13. Land-use Leakage

    SciTech Connect

    Calvin, Katherine V.; Edmonds, James A.; Clarke, Leon E.; Bond-Lamberty, Benjamin; Kim, Son H.; Wise, Marshall A.; Thomson, Allison M.; Kyle, G. Page

    2009-12-01

    Leakage occurs whenever actions to mitigate greenhouse gas emissions in one part of the world unleash countervailing forces elsewhere in the world so that reductions in global emissions are less than emissions mitigation in the mitigating region. While many researchers have examined the concept of industrial leakage, land-use policies can also result in leakage. We show that land-use leakage is potentially as large as or larger than industrial leakage. We identify two potential land-use leakage drivers, land-use policies and bioenergy. We distinguish between these two pathways and run numerical experiments for each. We also show that the land-use policy environment exerts a powerful influence on leakage and that under some policy designs leakage can be negative. International “offsets” are a potential mechanism to communicate emissions mitigation beyond the borders of emissions mitigating regions, but in a stabilization regime designed to limit radiative forcing to 3.7 2/m2, this also implies greater emissions mitigation commitments on the part of mitigating regions.

  14. The Hypothesis that the Genetic Code Originated in Coupled Synthesis of Proteins and the Evolutionary Predecessors of Nucleic Acids in Primitive Cells

    PubMed Central

    Francis, Brian R.

    2015-01-01

    Although analysis of the genetic code has allowed explanations for its evolution to be proposed, little evidence exists in biochemistry and molecular biology to offer an explanation for the origin of the genetic code. In particular, two features of biology make the origin of the genetic code difficult to understand. First, nucleic acids are highly complicated polymers requiring numerous enzymes for biosynthesis. Secondly, proteins have a simple backbone with a set of 20 different amino acid side chains synthesized by a highly complicated ribosomal process in which mRNA sequences are read in triplets. Apparently, both nucleic acid and protein syntheses have extensive evolutionary histories. Supporting these processes is a complex metabolism and at the hub of metabolism are the carboxylic acid cycles. This paper advances the hypothesis that the earliest predecessor of the nucleic acids was a β-linked polyester made from malic acid, a highly conserved metabolite in the carboxylic acid cycles. In the β-linked polyester, the side chains are carboxylic acid groups capable of forming interstrand double hydrogen bonds. Evolution of the nucleic acids involved changes to the backbone and side chain of poly(β-d-malic acid). Conversion of the side chain carboxylic acid into a carboxamide or a longer side chain bearing a carboxamide group, allowed information polymers to form amide pairs between polyester chains. Aminoacylation of the hydroxyl groups of malic acid and its derivatives with simple amino acids such as glycine and alanine allowed coupling of polyester synthesis and protein synthesis. Use of polypeptides containing glycine and l-alanine for activation of two different monomers with either glycine or l-alanine allowed simple coded autocatalytic synthesis of polyesters and polypeptides and established the first genetic code. A primitive cell capable of supporting electron transport, thioester synthesis, reduction reactions, and synthesis of polyesters and

  15. Shroud leakage flow discouragers

    DOEpatents

    Bailey, Jeremy Clyde; Bunker, Ronald Scott

    2002-01-01

    A turbine assembly includes a plurality of rotor blades comprising a root portion, an airfoil having a pressure sidewall and a suction sidewall, and a top portion having a cap. An outer shroud is concentrically disposed about said rotor blades, said shroud in combination with said tip portions defining a clearance gap. At least one circumferential shroud leakage discourager is disposed within the shroud. The leakage discourager(s) increase the flow resistance and thus reduce the flow of hot gas flow leakage for a given pressure differential across the clearance gap to improve overall turbine efficiency.

  16. Universal leakage elimination

    SciTech Connect

    Byrd, Mark S.; Lidar, Daniel A.; Wu, L.-A.; Zanardi, Paolo

    2005-05-15

    'Leakage' errors are particularly serious errors which couple states within a code subspace to states outside of that subspace, thus destroying the error protection benefit afforded by an encoded state. We generalize an earlier method for producing leakage elimination decoupling operations and examine the effects of the leakage eliminating operations on decoherence-free or noiseless subsystems which encode one logical, or protected qubit into three or four qubits. We find that by eliminating a large class of leakage errors, under some circumstances, we can create the conditions for a decoherence-free evolution. In other cases we identify a combined decoherence-free and quantum error correcting code which could eliminate errors in solid-state qubits with anisotropic exchange interaction Hamiltonians and enable universal quantum computing with only these interactions.

  17. Quinolinic Acid Responses during Interferon-α-Induced Depressive Symptomatology in Patients with Chronic Hepatitis C Infection - A Novel Aspect for Depression and Inflammatory Hypothesis

    PubMed Central

    Baranyi, Andreas; Meinitzer, Andreas; Breitenecker, Robert J.; Amouzadeh-Ghadikolai, Omid; Stauber, Rudolf; Rothenhäusler, Hans-Bernd

    2015-01-01

    Background The aim of this exploratory study is to gain for the first time a more comprehensive picture of the impact of changes of quinolinic acid concentrations on depressive symptomatology during and after IFN-α therapy. Methods The quinolinic acid concentrations of 35 HCV patients are examined in a prospective survey over the entire period of IFN-α treatment as well as three months later at six different times (baseline, one, three, six and nine months after the beginning of IFN-α treatment, and after the end of treatment). Results During IFN-α treatment Hamilton Depression Rating Scale scores rise significantly. At the same time there is greater activity of indoleamine 2,3-dioxygenase, with a resulting increase in plasma kynurenine concentrations. Compared to baseline values quinolinic acid concentrations increase significantly during therapy, reflecting an increased neurotoxic challenge. In addition, patients with higher scores in the Hamilton Depression Rating Scale at six and nine months after starting therapy show significantly higher levels of quinolinic acid concentration. Conclusions The increase of quinolinic acid during IFN-α therapy might contribute to depressive symptomatology through the neurotoxic challenge caused by quinolinic acid. Subsequently, our exploratory study results support the inflammatory hypothesis of depression. The awareness of relevant risk factors of IFN-α treatment-induced depression is essential to develop preventative treatment strategies. PMID:26368809

  18. Effects of dietary fats on plasma lipids and lipoproteins: an hypothesis for the lipid-lowering effect of unsaturated fatty acids

    PubMed Central

    Spritz, Norton; Mishkel, Maurice A.

    1969-01-01

    Several aspects of the effects of dietary fat on plasma lipids and lipoproteins were investigated in 12 subjects during the long-term feeding of formulas containing 40% of their calories as either saturated or unsaturated fats. The changes in fatty acid composition of plasma lipids, shown previously to occur after prolonged feedings of a dietary fat, required 10-14 days to be complete and were synchronous with the effect of the fat on plasma lipid concentrations. The change in lipid concentration occurred in low but not in high density lipoproteins. The effects on lipid levels of the low density lipoproteins were found to occur with little or no effect on the concentration of the protein moiety of these lipoproteins; as a result, cholesterol- and phospholipid to protein ratios in low density lipoproteins fell during unsaturated fat feeding. The effects of dietary fat on plasma phospholipids were studied in detail: the relative amounts of phosphatidylcholine, phosphatidylethanolamine, sphingomyelin, and lysophosphatidylcholine were unaffected by the type of dietary fat. However, the molecular species of phosphatidylcholine were markedly affected. More than 90% of the fatty acids at the α-position were saturated during both saturated and unsaturated feedings. In contrast, during unsaturated feedings, linoleate at the β-position outnumbered oleate by approximately 4:1, whereas during saturated feedings these two types of fatty acids were present in nearly equal amounts. This paper also presents the following hypothesis for the lipid-lowering effect of unsaturated dietary fat: since unsaturated fatty acids occupy a greater area than saturated acids, they alter the spatial configuration of the lipids into which they are incorporated; as a result, fewer lipid molecules can be accommodated by the apoprotein of the low-density lipoproteins (LDL), and thus the lipid content of the lipoprotein is lowered. The experimental findings of this study, while not proving this

  19. Life Origination Hydrate Hypothesis (LOH-Hypothesis)

    PubMed Central

    Ostrovskii, Victor; Kadyshevich, Elena

    2012-01-01

    The paper develops the Life Origination Hydrate Hypothesis (LOH-hypothesis), according to which living-matter simplest elements (LMSEs, which are N-bases, riboses, nucleosides, nucleotides), DNA- and RNA-like molecules, amino-acids, and proto-cells repeatedly originated on the basis of thermodynamically controlled, natural, and inevitable processes governed by universal physical and chemical laws from CH4, niters, and phosphates under the Earth's surface or seabed within the crystal cavities of the honeycomb methane-hydrate structure at low temperatures; the chemical processes passed slowly through all successive chemical steps in the direction that is determined by a gradual decrease in the Gibbs free energy of reacting systems. The hypothesis formulation method is based on the thermodynamic directedness of natural movement and consists ofan attempt to mentally backtrack on the progression of nature and thus reveal principal milestones alongits route. The changes in Gibbs free energy are estimated for different steps of the living-matter origination process; special attention is paid to the processes of proto-cell formation. Just the occurrence of the gas-hydrate periodic honeycomb matrix filled with LMSEs almost completely in its final state accounts for size limitation in the DNA functional groups and the nonrandom location of N-bases in the DNA chains. The slowness of the low-temperature chemical transformations and their “thermodynamic front” guide the gross process of living matter origination and its successive steps. It is shown that the hypothesis is thermodynamically justified and testable and that many observed natural phenomena count in its favor. PMID:25382120

  20. Life Origination Hydrate Hypothesis (LOH-Hypothesis).

    PubMed

    Ostrovskii, Victor; Kadyshevich, Elena

    2012-01-01

    The paper develops the Life Origination Hydrate Hypothesis (LOH-hypothesis), according to which living-matter simplest elements (LMSEs, which are N-bases, riboses, nucleosides, nucleotides), DNA- and RNA-like molecules, amino-acids, and proto-cells repeatedly originated on the basis of thermodynamically controlled, natural, and inevitable processes governed by universal physical and chemical laws from CH4, niters, and phosphates under the Earth's surface or seabed within the crystal cavities of the honeycomb methane-hydrate structure at low temperatures; the chemical processes passed slowly through all successive chemical steps in the direction that is determined by a gradual decrease in the Gibbs free energy of reacting systems. The hypothesis formulation method is based on the thermodynamic directedness of natural movement and consists ofan attempt to mentally backtrack on the progression of nature and thus reveal principal milestones alongits route. The changes in Gibbs free energy are estimated for different steps of the living-matter origination process; special attention is paid to the processes of proto-cell formation. Just the occurrence of the gas-hydrate periodic honeycomb matrix filled with LMSEs almost completely in its final state accounts for size limitation in the DNA functional groups and the nonrandom location of N-bases in the DNA chains. The slowness of the low-temperature chemical transformations and their "thermodynamic front" guide the gross process of living matter origination and its successive steps. It is shown that the hypothesis is thermodynamically justified and testable and that many observed natural phenomena count in its favor. PMID:25382120

  1. Impact of food supplementation and methionine on high densities of cotton rats: Support of the amino-acid-quality hypothesis?

    USGS Publications Warehouse

    Webb, R.E.; Leslie, David M.; Lochmiller, R.L.; Masters, R.E.

    2005-01-01

    Considerable research supports the tenet that quantity and quality of food limit vertebrate populations. We evaluated predictions that increased availabilities of food and the essential amino acid methionine were related to population limitation of the hispid cotton rat (Sigmodon hispidus). Effects of supplemental food and methionine on density, survival, and reproductive parameters of wild cotton rats were assessed in north-central Oklahoma in 1998-1999. Twelve enclosed groups of 16 adult cotton rats each (8 male, 8 female) were randomly assigned to either no supplementation (control), supplementation with a mixed ration that had methionine at slightly below maintenance levels (0.20%), or a methionine-enhanced mixed ration (1.20%). In general, densities of cotton rats were twice as high and were sustained longer with dietary supplementation, and methionine-supplemented populations maintained the highest densities. Treatment effects on survival depended on time of year, with higher survival in supplemented enclosures in October and November. Per capita recruitment was highest with methionine-enhanced food. Treatment effects on proportions of overall and female cotton rats in reproductive condition depended on sampling date, but males were most reproductively active with methionine supplementation. Methionine supplementation resulted in an earlier and longer reproductive season. Density-dependent and density-independent factors no doubt interplay to determine population dynamics of cotton rats, but our results suggest that methionine plays a role in the population dynamics of wild cotton rats, apparently by enhancing overall density, recruitment, and reproductive activity of males.

  2. Is the interaction between fatty acids and tryptophan responsible for the efficacy of a ketogenic diet in epilepsy? The new hypothesis of action.

    PubMed

    Maciejak, P; Szyndler, J; Turzyńska, D; Sobolewska, A; Kołosowska, K; Krząścik, P; Płaźnik, A

    2016-01-28

    The effects of a ketogenic diet in controlling seizure activity have been proven in many studies, although its mechanism of action remains elusive in many regards. We hypothesize that the ketogenic diet may exert its antiepileptic effects by influencing tryptophan (TRP) metabolism. The aim of this study was to investigate the influence of octanoic and decanoic fatty acids (FAs), the main components in the MCT diet (medium-chain triglyceride diet, a subtype of the ketogenic diet), on the metabolism of TRP, the activity of the kynurenic pathway and the concentrations of monoamines and amino acids, including branched-chain amino acids (BCAA) and aromatic amino acids (AAA) in rats. The acute effects of FA on the sedation index and hippocampal electrical after-discharge threshold were also assessed. We observed that intragastric administration of FA increased the brain levels of TRP and the central and peripheral concentrations of kynurenic acid (KYNA), as well as caused significant changes in the brain and plasma concentrations of BCAA and AAA. We found that the administration of FA clearly increased the seizure threshold and induced sedation. Furthermore, we have demonstrated that blocking TRP passage into the brain abolished these effects of FA but had no similar effect on the formation of ketone bodies. Given that FAs are major components of a ketogenic diet, it is suggested that the anticonvulsant effects of a ketogenic diet may be at least partly dependent on changes in TRP metabolism. We also propose a more general hypothesis concerning the intracellular mechanism of the ketogenic diet. PMID:26601775

  3. Prehistory of the notion of circulating nucleic acids in plasma/serum (CNAPS): birth of a hypothesis.

    PubMed

    Stroun, Maurice; Anker, Philippe

    2006-09-01

    In the late 50s and early 60s of the last century, a theoretical fight was taking place between Western and Russian scientists about the theory explaining the mechanism of evolution. According to neo-Darwinism, evolution was the result of hazard and necessity, that is, mutations arriving by chance favoring the survival of the fittest. For the Russian geneticists, acquired characteristics were the basis of evolution, that is, the environment modified the characteristics of the gene. One of the main experiments on which the Russian geneticists based their theory was the transmission of hereditary characteristics by a special technique of grafting between two varieties of plants-a mentor plant and a pupil plant. The pupil variety being entirely dependent on the development of the mentor plant its hereditary characteristics were modified accordingly. In the Western world these experiments were regarded with doubt. We were among the few who tried to repeat this kind of experiment. After three generations of grafting between two varieties of eggplant, we succeeded in obtaining hereditary modifications of the pupil plants, which acquired some of the characteristics of the mentor variety. The linkage between some hereditary characteristics of the mentor plant were broken, the segregation of the offspring was abnormal, dominant characteristics appearing in the offspring of a recessive plant. Rather than adopting the views of the Russian scientists about acquired characteristics, we suggested that DNA was circulating between the mentor and pupil plants and assumed that some nucleic acid molecules bearing genetic information could enter the somatic and reproductive cells of the pupil plant at a propitious moment and remain active.

  4. Electrical leakage detection circuit

    DOEpatents

    Wild, Arthur

    2006-09-05

    A method is provided for detecting electrical leakage between a power supply and a frame of a vehicle or machine. The disclosed method includes coupling a first capacitor between a frame and a first terminal of a power supply for a predetermined period of time. The current flowing between the frame and the first capacitor is limited to a predetermined current limit. It is determined whether the voltage across the first capacitor exceeds a threshold voltage. A first output signal is provided when the voltage across the capacitor exceeds the threshold voltage.

  5. A linear model of the effects of disturbance on dissolved nitrogen leakage from forested watersheds

    NASA Astrophysics Data System (ADS)

    Eshleman, Keith N.

    2000-11-01

    The leakage of dissolved nitrogen (N), primarily in the form of nitrate, from forested watersheds in the mid-Appalachian region has important water quality ramifications for small acid-sensitive streams and for downstream receiving waters such as Chesapeake Bay. Dissolved N leakage is a common, well-documented response of forested watersheds to forest management practices such as clear-cutting. Patterns of N leakage from mid-Appalachian watersheds during the late 1980s and early 1990s have also been shown to display considerable temporal and spatial synchrony with outbreaks of defoliation by the gypsy moth (Lymantria dispar) larva (a nonnative forest insect pest). This evidence suggests that forest disturbance may be an important contributor to N leakage in the mid-Appalachian region. A logical first step in testing this hypothesis is evaluating the ability of a simple, unit nitrogen export response function (UNERF) model to explain temporal changes in annual N export from gaged forested watersheds in the years following disturbance. Annual N export data from seven such watersheds were analyzed as part of the study: two small (<0.5 km2) watersheds subjected to deforestation and five larger (1.6-12.6 km2) watersheds subjected to repetitive defoliation by the gypsy moth larva. Several forms of linear UNERF models, parameterized by deconvolution of annual time series of N export using linear programming or by a least squares method, were generally found to be minimally biased and to explain high percentages (38-98%) of the total variation in annual N export. Despite their neglect of spatial and temporal ecosystem nonlinearities these linear models appear reasonably robust, making them at least as useful as their more complex nonlinear brethren for purposes of regionalization.

  6. Duct Leakage Repeatability Testing

    SciTech Connect

    Walker, Iain; Sherman, Max

    2014-08-01

    The purpose of this report is to evaluate the repeatability of the three most significant measurement techniques for duct leakage using data from the literature and recently obtained field data. We will also briefly discuss the first two factors. The main question to be answered by this study is to determine if differences in the repeatability of these tests methods is sufficient to indicate that any of these methods is so poor that it should be excluded from consideration as an allowed procedure in codes and standards. The three duct leak measurement methods assessed in this report are the two duct pressurization methods that are commonly used by many practitioners and the DeltaQ technique. These are methods B, C and A, respectively of the ASTM E1554 standard. Although it would be useful to evaluate other duct leak test methods, this study focused on those test methods that are commonly used and are required in various test standards, such as BPI (2010), RESNET (2014), ASHRAE 62.2 (2013), California Title 24 (CEC 2012), DOE Weatherization and many other energy efficiency programs.

  7. Duct Leakage Repeatability Testing

    SciTech Connect

    Walker, Iain; Sherman, Max

    2014-01-01

    Duct leakage often needs to be measured to demonstrate compliance with requirements or to determine energy or Indoor Air Quality (IAQ) impacts. Testing is often done using standards such as ASTM E1554 (ASTM 2013) or California Title 24 (California Energy Commission 2013 & 2013b), but there are several choices of methods available within the accepted standards. Determining which method to use or not use requires an evaluation of those methods in the context of the particular needs. Three factors that are important considerations are the cost of the measurement, the accuracy of the measurement and the repeatability of the measurement. The purpose of this report is to evaluate the repeatability of the three most significant measurement techniques using data from the literature and recently obtained field data. We will also briefly discuss the first two factors. The main question to be answered by this study is to determine if differences in the repeatability of these tests methods is sufficient to indicate that any of these methods is so poor that it should be excluded from consideration as an allowed procedure in codes and standards.

  8. Multifamily Envelope Leakage Model

    SciTech Connect

    Faakye, Omari; Griffiths, Dianne

    2015-05-08

    “The cost for blower testing is high, because it is labor intensive, and it may disrupt occupants in multiple units. This high cost and disruption deter program participants, and dissuade them from pursuing energy improvements that would trigger air leakage testing, such as improvements to the building envelope.” This statement found in a 2012 report by Heschong Mahone Group for several California interests emphasizes the importance of reducing the cost and complexity of blower testing in multifamily buildings. Energy efficiency opportunities are being bypassed. The cost of single blower testing is on the order of $300. The cost for guarded blower door testing—the more appropriate test for assessing energy savings opportunities—could easily be six times that, and that’s only if you have the equipment and simultaneous access to multiple apartments. Thus, the proper test is simply not performed. This research seeks to provide an algorithm for predicting the guarded blower door test result based upon a single, total blower door test.

  9. Application Of The Climafor Baseline To Determine Leakage: TheCase Of Scolel Te.

    SciTech Connect

    De Jong, B.H.J.; Bazan, E. Esquivel; Quechulpa Montalvo, S.

    2007-06-01

    The acceptance of forestry-based project activities tomitigate greenhouse gases emissions has been subjected to a number ofmethodological questions to be answered, of which the most challengingare baseline establishment and identification of and measuring leakage.Here we pose hypotheses for and quantify leakage of the Scolel Te projectin Chiapas, Mexico. In this project small-scale farmers are implementingforestry, agroforestry, and forest conservation activities, with carbonsequestration as one of the goals. The main leakage monitoring domain isdefined as the area owned by the participating farmers or communitiesoutside the area where the specific project activities take place. Thenull-hypothesis (no leakage) is that non-project land owned by the farmeror community will experience the same carbon stock changes as predictedby the regional baseline, specifically developed for the project. Firstwe assessed the most likely causes and sources of leakage that may occurin the project. From this analysis, one type of leakage seems to beimportant, i.e., activity shifting. Second we estimated the leakage of asample of participating farmers and communities. Actual land use was thencompared with expected land use derived from the baseline. The Plan Vivoof each participant, complemented with readily available tools toidentify the main sources and drivers of leakage are used to developsimple leakage assessment procedures, as demonstrated in this paper.Negative leakage was estimated to be negligible in this study.Incorporating these procedures already in the project planning stage willreduce the uncertainties related to the actual carbon mitigationpotential of any forestry project.

  10. 49 CFR 230.78 - Leakage.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 4 2011-10-01 2011-10-01 false Leakage. 230.78 Section 230.78 Transportation... Signal Equipment § 230.78 Leakage. (a) Main reservoirs and related piping. Leakage from main reservoir... to 60 percent of the maximum operating pressure. (b) Brake cylinders. Leakage from brake...

  11. 49 CFR 230.78 - Leakage.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 49 Transportation 4 2014-10-01 2014-10-01 false Leakage. 230.78 Section 230.78 Transportation... Signal Equipment § 230.78 Leakage. (a) Main reservoirs and related piping. Leakage from main reservoir... to 60 percent of the maximum operating pressure. (b) Brake cylinders. Leakage from brake...

  12. 49 CFR 230.78 - Leakage.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Leakage. 230.78 Section 230.78 Transportation... Signal Equipment § 230.78 Leakage. (a) Main reservoirs and related piping. Leakage from main reservoir... to 60 percent of the maximum operating pressure. (b) Brake cylinders. Leakage from brake...

  13. 49 CFR 230.78 - Leakage.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 49 Transportation 4 2012-10-01 2012-10-01 false Leakage. 230.78 Section 230.78 Transportation... Signal Equipment § 230.78 Leakage. (a) Main reservoirs and related piping. Leakage from main reservoir... to 60 percent of the maximum operating pressure. (b) Brake cylinders. Leakage from brake...

  14. 49 CFR 230.78 - Leakage.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 49 Transportation 4 2013-10-01 2013-10-01 false Leakage. 230.78 Section 230.78 Transportation... Signal Equipment § 230.78 Leakage. (a) Main reservoirs and related piping. Leakage from main reservoir... to 60 percent of the maximum operating pressure. (b) Brake cylinders. Leakage from brake...

  15. Physiopathological hypothesis of cellulite.

    PubMed

    de Godoy, José Maria Pereira; de Godoy, Maria de Fátima Guerreiro

    2009-08-31

    A series of questions are asked concerning this condition including as regards to its name, the consensus about the histopathological findings, physiological hypothesis and treatment of the disease. We established a hypothesis for cellulite and confirmed that the clinical response is compatible with this hypothesis. Hence this novel approach brings a modern physiological concept with physiopathologic basis and clinical proof of the hypothesis. We emphasize that the choice of patient, correct diagnosis of cellulite and the technique employed are fundamental to success.

  16. Robust characterization of leakage errors

    NASA Astrophysics Data System (ADS)

    Wallman, Joel J.; Barnhill, Marie; Emerson, Joseph

    2016-04-01

    Leakage errors arise when the quantum state leaks out of some subspace of interest, for example, the two-level subspace of a multi-level system defining a computational ‘qubit’, the logical code space of a quantum error-correcting code, or a decoherence-free subspace. Leakage errors pose a distinct challenge to quantum control relative to the more well-studied decoherence errors and can be a limiting factor to achieving fault-tolerant quantum computation. Here we present a scalable and robust randomized benchmarking protocol for quickly estimating the leakage rate due to an arbitrary Markovian noise process on a larger system. We illustrate the reliability of the protocol through numerical simulations.

  17. Air-leakage control manual

    SciTech Connect

    Maloney, J.

    1991-05-01

    This manual is for builders and designers who are interested in building energy-efficient homes. The purpose of the manual is to provide the ``how and why`` of controlling air leakage by means of a system called the ``Simple Caulk and Seal`` (SIMPLE{center_dot}CS) system. This manual provides an overview of the purpose and contents of the manual; It discusses the forces that affect air leakage in homes and the benefits of controlling air leakage. Also discussed are two earlier approaches for controlling air leakage and the problems with these approaches. It describes the SIMPLE-{center_dot}CS system. It outlines the standard components of the building envelope that require sealing and provides guidelines for sealing them. It outlines a step-by-step procedure for analyzing and planning the sealing effort. The procedure includes (1) identifying areas to be sealed, (2) determining the most effective and convenient stage of construction in which to do the sealing, and (3) designating the appropriate crew member or trade to be responsible for the sealing.

  18. Air-Leakage Control Manual.

    SciTech Connect

    Maloney, Jim; Washington State Energy Office; United States. Bonneville Power Administration.

    1991-05-01

    This manual is for builders and designers who are interested in building energy-efficient homes. The purpose of the manual is to provide the how and why'' of controlling air leakage by means of a system called the Simple Caulk and Seal'' (SIMPLE{center dot}CS) system. This manual provides an overview of the purpose and contents of the manual; It discusses the forces that affect air leakage in homes and the benefits of controlling air leakage. Also discussed are two earlier approaches for controlling air leakage and the problems with these approaches. It describes the SIMPLE-{center dot}CS system. It outlines the standard components of the building envelope that require sealing and provides guidelines for sealing them. It outlines a step-by-step procedure for analyzing and planning the sealing effort. The procedure includes (1) identifying areas to be sealed, (2) determining the most effective and convenient stage of construction in which to do the sealing, and (3) designating the appropriate crew member or trade to be responsible for the sealing.

  19. Physiopathological Hypothesis of Cellulite

    PubMed Central

    de Godoy, José Maria Pereira; de Godoy, Maria de Fátima Guerreiro

    2009-01-01

    A series of questions are asked concerning this condition including as regards to its name, the consensus about the histopathological findings, physiological hypothesis and treatment of the disease. We established a hypothesis for cellulite and confirmed that the clinical response is compatible with this hypothesis. Hence this novel approach brings a modern physiological concept with physiopathologic basis and clinical proof of the hypothesis. We emphasize that the choice of patient, correct diagnosis of cellulite and the technique employed are fundamental to success. PMID:19756187

  20. 16 CFR 1507.5 - Pyrotechnic leakage.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 16 Commercial Practices 2 2010-01-01 2010-01-01 false Pyrotechnic leakage. 1507.5 Section 1507.5... FIREWORKS DEVICES § 1507.5 Pyrotechnic leakage. The pyrotechnic chamber in fireworks devices shall be sealed in a manner that prevents leakage of the pyrotechnic composition during shipping, handling,...

  1. 49 CFR 229.59 - Leakage.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Leakage. 229.59 Section 229.59 Transportation... TRANSPORTATION RAILROAD LOCOMOTIVE SAFETY STANDARDS Safety Requirements Brake System § 229.59 Leakage. (a) Leakage from the main air reservoir and related piping may not exceed an average of 3 pounds per...

  2. 16 CFR 1507.5 - Pyrotechnic leakage.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 16 Commercial Practices 2 2011-01-01 2011-01-01 false Pyrotechnic leakage. 1507.5 Section 1507.5... FIREWORKS DEVICES § 1507.5 Pyrotechnic leakage. The pyrotechnic chamber in fireworks devices shall be sealed in a manner that prevents leakage of the pyrotechnic composition during shipping, handling,...

  3. 16 CFR 1507.5 - Pyrotechnic leakage.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 16 Commercial Practices 2 2012-01-01 2012-01-01 false Pyrotechnic leakage. 1507.5 Section 1507.5... FIREWORKS DEVICES § 1507.5 Pyrotechnic leakage. The pyrotechnic chamber in fireworks devices shall be sealed in a manner that prevents leakage of the pyrotechnic composition during shipping, handling,...

  4. 49 CFR 229.59 - Leakage.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 49 Transportation 4 2013-10-01 2013-10-01 false Leakage. 229.59 Section 229.59 Transportation... TRANSPORTATION RAILROAD LOCOMOTIVE SAFETY STANDARDS Safety Requirements Brake System § 229.59 Leakage. (a) Leakage from the main air reservoir and related piping may not exceed an average of 3 pounds per...

  5. 49 CFR 229.59 - Leakage.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 49 Transportation 4 2012-10-01 2012-10-01 false Leakage. 229.59 Section 229.59 Transportation... TRANSPORTATION RAILROAD LOCOMOTIVE SAFETY STANDARDS Safety Requirements Brake System § 229.59 Leakage. (a) Leakage from the main air reservoir and related piping may not exceed an average of 3 pounds per...

  6. 49 CFR 229.59 - Leakage.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 4 2011-10-01 2011-10-01 false Leakage. 229.59 Section 229.59 Transportation... TRANSPORTATION RAILROAD LOCOMOTIVE SAFETY STANDARDS Safety Requirements Brake System § 229.59 Leakage. (a) Leakage from the main air reservoir and related piping may not exceed an average of 3 pounds per...

  7. 49 CFR 229.59 - Leakage.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 49 Transportation 4 2014-10-01 2014-10-01 false Leakage. 229.59 Section 229.59 Transportation... TRANSPORTATION RAILROAD LOCOMOTIVE SAFETY STANDARDS Safety Requirements Brake System § 229.59 Leakage. (a) Leakage from the main air reservoir and related piping may not exceed an average of 3 pounds per...

  8. 16 CFR 1507.5 - Pyrotechnic leakage.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 16 Commercial Practices 2 2013-01-01 2013-01-01 false Pyrotechnic leakage. 1507.5 Section 1507.5... FIREWORKS DEVICES § 1507.5 Pyrotechnic leakage. The pyrotechnic chamber in fireworks devices shall be sealed in a manner that prevents leakage of the pyrotechnic composition during shipping, handling,...

  9. 16 CFR 1507.5 - Pyrotechnic leakage.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 16 Commercial Practices 2 2014-01-01 2014-01-01 false Pyrotechnic leakage. 1507.5 Section 1507.5... FIREWORKS DEVICES § 1507.5 Pyrotechnic leakage. The pyrotechnic chamber in fireworks devices shall be sealed in a manner that prevents leakage of the pyrotechnic composition during shipping, handling,...

  10. "Geyser" leakage on fluorescein angiography.

    PubMed

    Levy, Jaime; Fagan, Xavier J; Lifshitz, Tova; Schneck, Marina

    2013-11-22

    An 82-year-old patient with diabetes was followed up due to moderate nonproliferative diabetic retinopathy with macular edema in the right eye. Visual acuity was 6/36. Focal macular laser was conducted (A). Three years later, the patient presented with blurry vision in the right eye. Visual acuity was 3/60. Vitreous hemorrhage was observed (B), and neovascularization of the disc was suspected (C). Fluorescein angiography (D, mid venous phase; E-F, recirculation phase) confirmed neovascularization of the disc and depicted a striking vertical leakage. Panretinal photocoagulation was started. Possible explanations for the "geyser" leakage may be either a partial posterior vitreous detachment allowing the fluorescein to track upwards but not elsewhere or a pocket of syneretic vitreous allowing the fluorescein passage in which to diffuse, much like the passage the blood would have taken.

  11. "Geyser" leakage on fluorescein angiography.

    PubMed

    Levy, Jaime; Fagan, Xavier J; Lifshitz, Tova; Schneck, Marina

    2013-01-01

    An 82-year-old patient with diabetes was followed up due to moderate nonproliferative diabetic retinopathy with macular edema in the right eye. Visual acuity was 6/36. Focal macular laser was conducted (A). Three years later, the patient presented with blurry vision in the right eye. Visual acuity was 3/60. Vitreous hemorrhage was observed (B), and neovascularization of the disc was suspected (C). Fluorescein angiography (D, mid venous phase; E-F, recirculation phase) confirmed neovascularization of the disc and depicted a striking vertical leakage. Panretinal photocoagulation was started. Possible explanations for the "geyser" leakage may be either a partial posterior vitreous detachment allowing the fluorescein to track upwards but not elsewhere or a pocket of syneretic vitreous allowing the fluorescein passage in which to diffuse, much like the passage the blood would have taken. PMID:24548789

  12. Heat exchanger leakage problem location

    NASA Astrophysics Data System (ADS)

    Hejčík, Jiří; Jícha, Miroslav

    2012-04-01

    Recent compact heat exchangers are very often assembled from numerous parts joined together to separate heat transfer fluids and to form the required heat exchanger arrangement. Therefore, the leak tightness is very important property of the compact heat exchangers. Although, the compact heat exchangers have been produced for many years, there are still technological problems associated with manufacturing of the ideal connection between the individual parts, mainly encountered with special purpose heat exchangers, e.g. gas turbine recuperators. This paper describes a procedure used to identify the leakage location inside the prime surface gas turbine recuperator. For this purpose, an analytical model of the leaky gas turbine recuperator was created to assess its performance. The results obtained are compared with the experimental data which were acquired during the recuperator thermal performance analysis. The differences between these two data sets are used to indicate possible leakage areas.

  13. Hypothesis analysis methods, hypothesis analysis devices, and articles of manufacture

    DOEpatents

    Sanfilippo, Antonio P.; Cowell, Andrew J.; Gregory, Michelle L.; Baddeley, Robert L.; Paulson, Patrick R.; Tratz, Stephen C.; Hohimer, Ryan E.

    2012-03-20

    Hypothesis analysis methods, hypothesis analysis devices, and articles of manufacture are described according to some aspects. In one aspect, a hypothesis analysis method includes providing a hypothesis, providing an indicator which at least one of supports and refutes the hypothesis, using the indicator, associating evidence with the hypothesis, weighting the association of the evidence with the hypothesis, and using the weighting, providing information regarding the accuracy of the hypothesis.

  14. Calculating the GONG Leakage Matrix

    NASA Astrophysics Data System (ADS)

    Hill, F.; Howe, R.

    Since spherical harmonics do not form a complete orthonormal basis set over a portion of a sphere, helioseismic spectra computed for a specific target mode with degree ellt and azimuthal degree mt also contain modes with nearby ell'' and m''. These spatial leaks greatly increase the complexity of the observed spectrum, complicating the spectral fitting and degrading the resulting mode parameter estimates. This is particularly true where the target mode and the leaks have similar frequencies. Some strategies for fitting helioseismic spectra explicitly include the leakage matrix which estimates the relative strength of a mode (ell'' and m'') in the spectrum at (ellt,mt). Since the fitting methods assume that the matrix is correct and apply it as a constraint, an inaccurate matrix introduces systematic errors in the estimated mode parameters. It is thus important to have as accurate a matrix as possible. Here we report on the calculation of the leakage matrix for the GONG observations. The matrix elements are essentially the integrals (over the observed portion of the solar surface) of the crossproducts of the two spherical harmonics. However, several effects have been included to increase the accuracy of the matrix. These include the projection factor of the observable (velocity, intensity, modulation), the spatial apodization applied to the data, the finite rectangular pixel dimensions of the observations, and possible errors in the estimated image geometry. Other factors to be incorporated are the observed MTF, the merging of the GONG images, and the horizontal components of the oscillatory velocity field. We will compare the latest calculation with the observed spectrum and assess the relative importance of the input factors. We will also compare the leakage matrices for velocity and intensity to estimate their contribution to the large apparent differences in the helioseismic spectra obtained from these observables.

  15. Hypothesis of Lithocoding: Origin of the Genetic Code as a "Double Jigsaw Puzzle" of Nucleobase-Containing Molecules and Amino Acids Assembled by Sequential Filling of Apatite Mineral Cellules.

    PubMed

    Skoblikow, Nikolai E; Zimin, Andrei A

    2016-05-01

    The hypothesis of direct coding, assuming the direct contact of pairs of coding molecules with amino acid side chains in hollow unit cells (cellules) of a regular crystal-structure mineral is proposed. The coding nucleobase-containing molecules in each cellule (named "lithocodon") partially shield each other; the remaining free space determines the stereochemical character of the filling side chain. Apatite-group minerals are considered as the most preferable for this type of coding (named "lithocoding"). A scheme of the cellule with certain stereometric parameters, providing for the isomeric selection of contacting molecules is proposed. We modelled the filling of cellules with molecules involved in direct coding, with the possibility of coding by their single combination for a group of stereochemically similar amino acids. The regular ordered arrangement of cellules enables the polymerization of amino acids and nucleobase-containing molecules in the same direction (named "lithotranslation") preventing the shift of coding. A table of the presumed "LithoCode" (possible and optimal lithocodon assignments for abiogenically synthesized α-amino acids involved in lithocoding and lithotranslation) is proposed. The magmatic nature of the mineral, abiogenic synthesis of organic molecules and polymerization events are considered within the framework of the proposed "volcanic scenario". PMID:27048216

  16. The dysconnection hypothesis (2016).

    PubMed

    Friston, Karl; Brown, Harriet R; Siemerkus, Jakob; Stephan, Klaas E

    2016-10-01

    Twenty years have passed since the dysconnection hypothesis was first proposed (Friston and Frith, 1995; Weinberger, 1993). In that time, neuroscience has witnessed tremendous advances: we now live in a world of non-invasive neuroanatomy, computational neuroimaging and the Bayesian brain. The genomics era has come and gone. Connectomics and large-scale neuroinformatics initiatives are emerging everywhere. So where is the dysconnection hypothesis now? This article considers how the notion of schizophrenia as a dysconnection syndrome has developed - and how it has been enriched by recent advances in clinical neuroscience. In particular, we examine the dysconnection hypothesis in the context of (i) theoretical neurobiology and computational psychiatry; (ii) the empirical insights afforded by neuroimaging and associated connectomics - and (iii) how bottom-up (molecular biology and genetics) and top-down (systems biology) perspectives are converging on the mechanisms and nature of dysconnections in schizophrenia. PMID:27450778

  17. The gender similarities hypothesis.

    PubMed

    Hyde, Janet Shibley

    2005-09-01

    The differences model, which argues that males and females are vastly different psychologically, dominates the popular media. Here, the author advances a very different view, the gender similarities hypothesis, which holds that males and females are similar on most, but not all, psychological variables. Results from a review of 46 meta-analyses support the gender similarities hypothesis. Gender differences can vary substantially in magnitude at different ages and depend on the context in which measurement occurs. Overinflated claims of gender differences carry substantial costs in areas such as the workplace and relationships. PMID:16173891

  18. The gender similarities hypothesis.

    PubMed

    Hyde, Janet Shibley

    2005-09-01

    The differences model, which argues that males and females are vastly different psychologically, dominates the popular media. Here, the author advances a very different view, the gender similarities hypothesis, which holds that males and females are similar on most, but not all, psychological variables. Results from a review of 46 meta-analyses support the gender similarities hypothesis. Gender differences can vary substantially in magnitude at different ages and depend on the context in which measurement occurs. Overinflated claims of gender differences carry substantial costs in areas such as the workplace and relationships.

  19. The Keystone Pathogen Hypothesis

    PubMed Central

    Hajishengallis, George; Darveau, Richard P.; Curtis, Michael A.

    2012-01-01

    Recent studies have highlighted the importance of the human microbiome in host health and disease. However, for the most part the mechanisms by which the microbiome mediates disease, or protection from it, remain poorly understood. The “keystone pathogen” hypothesis holds that certain low-abundance microbial pathogens can orchestrate inflammatory disease by remodelling a normally benign microbiota into a dysbiotic one. In this Opinion, we critically assess the available literature in support of this hypothesis, which may provide a novel conceptual basis for the development of targeted diagnostic and treatment modalities for complex dysbiotic diseases. PMID:22941505

  20. Reversal of corticosterone-induced BDNF alterations by the natural antioxidant alpha-lipoic acid alone and combined with desvenlafaxine: Emphasis on the neurotrophic hypothesis of depression.

    PubMed

    de Sousa, Caren Nádia Soares; Meneses, Lucas Nascimento; Vasconcelos, Germana Silva; Silva, Márcia Calheiros Chaves; da Silva, Jéssica Calheiros; Macêdo, Danielle; de Lucena, David Freitas; Vasconcelos, Silvânia Maria Mendes

    2015-12-15

    Brain derived neurotrophic factor (BDNF) is linked to the pathophysiology of depression. We hypothesized that BDNF is one of the neurobiological pathways related to the augmentation effect of alpha-lipoic acid (ALA) when associated with antidepressants. Female mice were administered vehicle or CORT 20mg/kg during 14 days. From the 15th to 21st days the animals were divided in groups that were further administered: vehicle, desvenlafaxine (DVS) 10 or 20mg/kg, ALA 100 or 200mg/kg or the combinations of DVS10+ALA100, DVS20+ALA100, DVS10+ALA200 or DVS20+ALA200. ALA or DVS alone or in combination reversed CORT-induced increase in immobility time in the forced swimming test and decrease in sucrose preference, presenting, thus, an antidepressant-like effect. DVS10 alone reversed CORT-induced decrease in BDNF in the prefrontal cortex (PFC), hippocampus (HC) and striatum (ST). The same was observed in the HC and ST of ALA200 treated animals. The combination of DVS and ALA200 reversed CORT-induced alterations in BDNF and even, in some cases, increased the levels of this neurotrophin when compared to vehicle-treated animals in HC and ST. Taken together, these results suggest that the combination of the DVS+ALA may be valuable for treating conditions in which BDNF levels are decreased, such as depression.

  1. Leakage-current properties of encapsulants

    NASA Technical Reports Server (NTRS)

    Wen, L. C.

    1986-01-01

    A theoretical modeling of leakage current in ethylene vinyl acetate (EVA) and polyvinyl butyral (PVB) modules is being developed and is described. The modeling effort derives mathematical relationships for the bulk and surface conductivites of EVA and PVB, the surface conductivities of glass and polymeric films, and the EVA and PVB pottants, all as functions of environmental parameters. Results from the modeling indicate that for glass/EVA, the glass surface controls the interfacial conductivity, although EVA bulk conductivity controls total leakage current. For PVB/glass, the interface conductivity controls leakage currents for relative humidity (RH) less than 40 to 50%, but PVB bulk conductivity controls leakage current above 50% RH.

  2. Improving stopping construction to minimize leakage

    PubMed Central

    Grau, Roy H.; Mazzella, Andrew L.; Martikainen, Anu L.

    2015-01-01

    The proper sealing of stoppings is an important step in reducing leakage from the intake to the return airways. Leakage and the subsequent loss of ventilation resulting from improperly sealed stoppings can lead to unhealthy and unsafe working conditions. The research presented in this paper investigates the total leakage of a stopping, including air leakage through the stopping, at the stopping perimeter, and through the coalbed. The study also examines sealing considerations for stoppings that are constructed under roof control screen, the effects that wooden wedges had on inhibiting efficient application of polyurethane foam sealant, and airflow leakage through the surrounding coal. The work involved building a stopping in a dead end room of the NIOSH Safety Research Coal Mine and then pressurising the room using compressed air. Stopping leakage was evaluated by measuring air pressure loss in the enclosed room due to the air leakage. Part of the research utilises a diluted soap solution that was applied to the stopping and the surrounding coal to detect air leakage signified by bubble formations. The results show that stopping leakage can be minimised with proper sealing PMID:26379366

  3. Surface-active properties of lipophilic antioxidants tyrosol and hydroxytyrosol fatty acid esters: a potential explanation for the nonlinear hypothesis of the antioxidant activity in oil-in-water emulsions.

    PubMed

    Lucas, Ricardo; Comelles, Francisco; Alcántara, David; Maldonado, Olivia S; Curcuroze, Melanie; Parra, Jose L; Morales, Juan C

    2010-07-14

    Our group has recently observed a nonlinear tendency in antioxidant capacity of different hydroxytyrosol fatty acid esters in fish oil-in-water emulsions, where a maximum of antioxidant efficiency appeared for hydroxytyrosol octanoate. These results appear to disagree with the antioxidant polar paradox. Because the physical location of the antioxidants in an oil-water interface has been postulated as an important factor in explaining this behavior, we have prepared a series of tyrosol and hydroxytyrosol fatty acid esters with different chain length and studied their surface-active properties in water, because these physicochemical parameters could be directly related to the preferential placement at the interface. We have found that tyrosol and hydroxytyrosol fatty acid esters are relevant surfactants when the right hydrophilic-lipophilic balance (HLB) is attained and, in some cases, as efficient as emulsifiers commonly used in industry, such as Brij 30 or Tween 20. Moreover, a nonlinear dependency of surfactant effectiveness is observed with the increase in chain length of the lipophilic antioxidants. This tendency seems to fit quite well with the reported antioxidant activity in emulsions, and the best antioxidant of the series (hydroxytyrosol octanoate) is also a very effective surfactant. This potential explanation of the nonlinear hypothesis will help in the rational design of antioxidants used in oil-in-water emulsions.

  4. The Qualitative Similarity Hypothesis

    ERIC Educational Resources Information Center

    Paul, Peter V.; Lee, Chongmin

    2010-01-01

    Evidence is presented for the qualitative similarity hypothesis (QSH) with respect to children and adolescents who are d/Deaf or hard of hearing. The primary focus is on the development of English language and literacy skills, and some information is provided on the acquisition of English as a second language. The QSH is briefly discussed within…

  5. Radiofrequency radiation leakage from microwave ovens.

    PubMed

    Lahham, Adnan; Sharabati, Afifeh

    2013-12-01

    This work presents data on the amount of radiation leakage from 117 microwave ovens in domestic and restaurant use in the West Bank, Palestine. The study of leakage is based on the measurements of radiation emissions from the oven in real-life conditions by using a frequency selective field strength measuring system. The power density from individual ovens was measured at a distance of 1 m and at the height of centre of door screen. The tested ovens were of different types, models with operating powers between 1000 and 1600 W and ages ranging from 1 month to >20 y, including 16 ovens with unknown ages. The amount of radiation leakage at a distance of 1 m was found to vary from 0.43 to 16.4 μW cm(-2) with an average value equalling 3.64 μW cm(-2). Leakages from all tested microwave ovens except for seven ovens (∼6 % of the total) were below 10 μW cm(-2). The highest radiation leakage from any tested oven was ∼16.4 μW cm(-2), and found in two cases only. In no case did the leakage exceed the limit of 1 mW cm(-2) recommended by the ICNIRP for 2.45-GHz radiofrequency. This study confirms a linear correlation between the amount of leakage and both oven age and operating power, with a stronger dependence of leakage on age.

  6. 49 CFR 236.735 - Current, leakage.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... Current, leakage. A stray electric current of relatively small value which flows through or across the... 49 Transportation 4 2010-10-01 2010-10-01 false Current, leakage. 236.735 Section 236.735 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL RAILROAD...

  7. 49 CFR 236.735 - Current, leakage.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... Current, leakage. A stray electric current of relatively small value which flows through or across the... 49 Transportation 4 2012-10-01 2012-10-01 false Current, leakage. 236.735 Section 236.735 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL RAILROAD...

  8. 49 CFR 236.735 - Current, leakage.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... Current, leakage. A stray electric current of relatively small value which flows through or across the... 49 Transportation 4 2011-10-01 2011-10-01 false Current, leakage. 236.735 Section 236.735 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL RAILROAD...

  9. 49 CFR 236.735 - Current, leakage.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... Current, leakage. A stray electric current of relatively small value which flows through or across the... 49 Transportation 4 2014-10-01 2014-10-01 false Current, leakage. 236.735 Section 236.735 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL RAILROAD...

  10. 49 CFR 236.735 - Current, leakage.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... Current, leakage. A stray electric current of relatively small value which flows through or across the... 49 Transportation 4 2013-10-01 2013-10-01 false Current, leakage. 236.735 Section 236.735 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL RAILROAD...

  11. Predicting Envelope Leakage in Attached Dwellings

    SciTech Connect

    Faakye, O.; Arena, L.; Griffiths, D.

    2013-07-01

    The most common method for measuring air leakage is to use a single blower door to pressurize and/or depressurize the test unit. In detached housing, the test unit is the entire home and the single blower door measures air leakage to the outside. In attached housing, this 'single unit', 'total', or 'solo' test method measures both the air leakage between adjacent units through common surfaces as well air leakage to the outside. Measuring and minimizing this total leakage is recommended to avoid indoor air quality issues between units, reduce energy losses to the outside, reduce pressure differentials between units, and control stack effect. However, two significant limitations of the total leakage measurement in attached housing are: for retrofit work, if total leakage is assumed to be all to the outside, the energy benefits of air sealing can be significantly over predicted; for new construction, the total leakage values may result in failing to meet an energy-based house tightness program criterion. The scope of this research is to investigate an approach for developing a viable simplified algorithm that can be used by contractors to assess energy efficiency program qualification and/or compliance based upon solo test results.

  12. Analysis of Leakage Flows in Turbomachinery

    NASA Technical Reports Server (NTRS)

    Sindir, M. M.

    1986-01-01

    Navier-Stokes calculations predict leakage flow in high-pressure fuel pump. Accurate calculation of internal turbomachinery flow dynamics helps spot possible failure modes and establishes coupling between cyclic loading and structural dynamics. Approach also useful in analyzing two-and quasi-three-dimensional leakage flows in other turbomachinery components.

  13. Bag Test Measures Leakage From Insulated Pipe

    NASA Technical Reports Server (NTRS)

    Schock, Kent D.; Easter, Barry P.

    1994-01-01

    Test quantifies leakage of gas from pipe even though pipe covered with insulation. Involves use of helium analyzer to measure concentration of helium in impermeable bag around pipe. Test administered after standard soap-solution bubble test indicates presence and general class of leakage.

  14. Calculating Leakage Around Turbopump Inducer Shrouds

    NASA Technical Reports Server (NTRS)

    Meng, Sen Yih; Sindir, Munir M.

    1987-01-01

    New mathematical model for leakage flow around shrouded turbopump inducers yields more realistic analyses from which designers determine best geometry for leakage-flow-reinjection ports. Also, designers use calculated velocity profile at inducer leading edge to determine blade-angle distribution of inducer leading edge.

  15. The interactive brain hypothesis

    PubMed Central

    Di Paolo, Ezequiel; De Jaegher, Hanne

    2012-01-01

    Enactive approaches foreground the role of interpersonal interaction in explanations of social understanding. This motivates, in combination with a recent interest in neuroscientific studies involving actual interactions, the question of how interactive processes relate to neural mechanisms involved in social understanding. We introduce the Interactive Brain Hypothesis (IBH) in order to help map the spectrum of possible relations between social interaction and neural processes. The hypothesis states that interactive experience and skills play enabling roles in both the development and current function of social brain mechanisms, even in cases where social understanding happens in the absence of immediate interaction. We examine the plausibility of this hypothesis against developmental and neurobiological evidence and contrast it with the widespread assumption that mindreading is crucial to all social cognition. We describe the elements of social interaction that bear most directly on this hypothesis and discuss the empirical possibilities open to social neuroscience. We propose that the link between coordination dynamics and social understanding can be best grasped by studying transitions between states of coordination. These transitions form part of the self-organization of interaction processes that characterize the dynamics of social engagement. The patterns and synergies of this self-organization help explain how individuals understand each other. Various possibilities for role-taking emerge during interaction, determining a spectrum of participation. This view contrasts sharply with the observational stance that has guided research in social neuroscience until recently. We also introduce the concept of readiness to interact to describe the practices and dispositions that are summoned in situations of social significance (even if not interactive). This latter idea links interactive factors to more classical observational scenarios. PMID:22701412

  16. Mesoamerican cosmovision: an hypothesis.

    NASA Astrophysics Data System (ADS)

    Franch, J. A.

    In the present conference the author explains a new hypothesis to interpret the cosmogonic vision of the people and the cultures from the Mesoamerican area during the precolumbian period. The hypothesis at issue consists in irregular octahedrical form, or as two pyramids jointed by the base in such a manner that the celestial pyramid has thirteen heavens in the form of platforms in such a way that the zenith is the seventh platform; on the contrary, the infraworld pyramid has nine platforms. The sequence of the heavens comes to an end in the number 13 heaven, or the West side of the world, that is to say the Omeyocan or the Tamoanchan, whereas the ninth infraworld is the Apochcalocan. This is the point of the intercommunication between the celestial world and the infraworld, the place of Death and Birth. In order to develop that hypothesis the author has a great number of ethnographic testimonies taken from Totonacs, Tzotziles, Mayas and, along with this, from Southamerican areas, as it is the case of the Kogi, of Colombia. The author has also considered the evidence that proceeds from the ancient codices as well as numerous samples of sculptures and reliefs, especially from the Aztec culture.

  17. Serotonergic hypothesis of sleepwalking.

    PubMed

    Juszczak, Grzegorz R; Swiergiel, Artur H

    2005-01-01

    Despite widespread prevalence of sleepwalking, its etiology and pathophysiology are not well understood. However, there is some evidence that sleepwalking can be precipitated by sleep-disordered breathing. A hypothesis is proposed that serotonergic system may be a link between sleep-disordered breathing and sleepwalking. Serotonergic neurons meet basic requirements for such a role because they are activated by hypercapnia, provide a tonic excitatory drive that gates afferent inputs to motoneurons, and the activity of serotonergic neurons can be dissociated from the level of arousal. This paper discusses also drug-induced somnambulism and co-occurrence of sleepwalking and other disorders such as migraine and febrile illness.

  18. Relationship between membrane damage, leakage of intracellular compounds, and inactivation of Escherichia coli treated by pressurized CO2.

    PubMed

    Yao, Chunyan; Li, Xiaodong; Bi, Weiwei; Jiang, Chen

    2014-08-01

    The relationship between membrane damage, leakage of intracellular compounds, and inactivation of Escherichia coli treated by pressurized CO2 was investigated by assessing the inactivation, bacterial cell membrane permeability, the leakage of protein, nucleic acid, and K(+) and Mg(2+) of E. coli. The results indicated that pressurized CO2 treatment induced the leakage of protein in E. coli, but the time of leakage was lagged behind the time of 99% E. coli inactivation, so it was only the secondary phenomenon of inactivation. The inactivation of E. coli was related to the leakage of nucleic acid, K(+) , Mg(2+) induced by the pressurized CO2 treatment. There was direct relationship between the inactivation of E. coli and the damaging effect of pressurized CO2 treatment on the cell membrane of E. coli.

  19. Air leakage of newly instaled residential windows

    SciTech Connect

    Weidt, J.; Weidt, J.

    1980-06-01

    The air-leakage characteristics of five major window designs were measured in a field survey conducted in Twin Cities, Minnesota. A total of 192 windows (16 manufacturers) were tested at 58 sites representing a cross-section of single-family homes, townhouses, low- and high-rise apartments, and condominiums. Air-leakage measurements of the installed windows were compared with the current standard used by industry and government of 0.50 ft/sup 3//min/linear ft of crack. Other parameters studied were: effect of sash and frame material, effect of leakage between window frame and wall, differences among the product lines of a single manufacturer and between manufacturers, effect of installation practices, effect of cold weather on performance, change in performance over time for older windows, and performance of fixed glazing. Based on industry and government standards, 40% of all windows tested showed air-leakage characteristics higher than the 0.50 cfm/lfc standard, and 60% exceeded manufacturers' specifications for performance which in some cases were lower than the general industry standard. Analysis of the impact of various parameters on air-leakage performance showed that the operational design of the window was the most critical determinant although the ranking changes if performance is expressed in cfm/unit area or cfm/opening area. Air leakage was measured using a portable pressurization chamber. Smoke pencils, thermographic techniques and extensive photographic documentation provided additional data as to the location and cause of air leakage problems.

  20. Constraining Effects of Brine Leakage from Carbon Sequestration Sites

    NASA Astrophysics Data System (ADS)

    Wunsch, A.; Navarre-Sitchler, A. K.; McCray, J. E.

    2011-12-01

    Research has shown that pressure build up associated with injection of CO2 into a deep saline aquifer has the potential to promote brine leakage into overlying formations. In order to understand and quantify chemical changes in an underground source of drinking water (USDW) invaded by deep saline brines, we analyzed over 90,000 brine geochemical data entries from the NETL NATCARB brine database to identify potential brine constituents of concern. Using a variety of statistical methods and EPA regulatory levels or standards (RLS) we narrowed the list of brine constituents of potential concern to USDWs to TDS, thallium, chloride, sulfate and arsenic. Somewhat surprisingly, the distribution of reported pH had a fairly narrow distribution around a median value of 7.4, with over 78% of values complying with EPA recommended secondary standard for drinking water acidity. The pH distribution implies that unlike pure CO2 leakage, far-field brine leakage (i.e., brine not in contact with CO2) is not expected to bear a low-pH signature, thus suggesting use of other means of geochemical monitoring for brine leakage, such as electrical conductivity. Geochemical mixing models of brine and dilute water were used to constrain mixing ratios where RLS values are exceeded for the TDS, thallium and chloride. TDS and chloride exceed the EPA secondary standards at a brine/USDW mixing ratio of 0.012 and 0.459, respectively. The thallium maximum contaminant level (MCL) is exceeded at a brine/USDW mixing ratio of 0.3753, smaller than the chloride mixing ratio. However, sorption and/or desorption processes may alter thallium concentrations along a leakage pathway resulting in lower concentrations in the aquifer than predicted by simple mixing models. While leakage into USDWs has received considerable attention, brine contamination of groundwater used for irrigation of agricultural crops is also an important area of research. Our calculations suggest that almost all crops grown in the United

  1. Composite seal reduces alkaline battery leakage

    NASA Technical Reports Server (NTRS)

    Clatterbuck, C. H.; Plitt, K. F.

    1965-01-01

    Composite seal consisting of rubber or plastic washers and a metal washer reduces alkaline battery leakage. Adhesive is applied to each washer interface, and the washers are held together mechanically.

  2. Temperature effects on soybean imbibition and leakage.

    PubMed

    Leopold, A C

    1980-06-01

    As a part of an analysis of the nature of chilling injury to seeds, measurements were made of the initial linear rates of water entry into and solute leakage out of cotyledons of soybean at various temperatures. Arrhenius plots were approximately linear for water entry into both living and dead cotyledons, with the slope (and activation energy) for entry into living cells being insignificantly higher than for dead cells, suggesting little effect of membrane barriers on water entry. The plots for solute leakage showed 10-fold lower leakage rates from living than from dead tissues; a reversal of slope in the Arrhenius plot at temperatures below 15 C reflected increasing leakage rates, interpreted as a quantitative disruption of membrane reorganization at the temperatures associated with chilling injury.

  3. Apparatus for detecting leakage of liquid sodium

    DOEpatents

    Himeno, Yoshiaki

    1978-01-01

    An apparatus for detecting the leakage of liquid sodium includes a cable-like sensor adapted to be secured to a wall of piping or other equipment having sodium on the opposite side of the wall, and the sensor includes a core wire electrically connected to the wall through a leak current detector and a power source. An accidental leakage of the liquid sodium causes the corrosion of a metallic layer and an insulative layer of the sensor by products resulted from a reaction of sodium with water or oxygen in the atmospheric air so as to decrease the resistance between the core wire and the wall. Thus, the leakage is detected as an increase in the leaking electrical current. The apparatus is especially adapted for use in detecting the leakage of liquid sodium from sodium-conveying pipes or equipment in a fast breeder reactor.

  4. Initial DAB Argon Storage Dewar Leakage

    SciTech Connect

    Dixon, K.; /Fermilab

    1990-05-30

    Any detectable leakage emanating from the argon storage dewar is undesirable; not only from a safety standpoint (eg, cryogenic burns, asphyxiation, etc.), but also small amounts of air back diffusing through leaks can render the argon unsuitable for the future physics experiments to take place within the cryostats. Whereas leakage through some of the control and manually operated valves on the dewar does not necessarily infroduce any of the above hazards directly, it could be high enough to be an economical, and perhaps an operational nuisance. Contained in the following is a compilation of the final leakage rates associated with the dewar during the period of January through May of 1990 and the raw data from which they were derived from. Also contained is a calculation of the total maximum allowable leakage rate int%ut of the dewar. The general strategy employed while leak checking the dewar was to eliminate all leaks found which could be relatively easily stopped and to reduce the more difficult ones to an acceptable level. Leakage past the seats/plugs of control and main relief valves in addition to leakage past the ball seals in the diverter valve fell into the latter category. Helium mass spectrometer leak detector (HMSLD), rate of rise (ROR) method, and throughput calculations based on effective pumping speeds were the means used to determine leakage rates. Usually the HMSLD method was used to detect the numerous smaller leaks (1 OE-S to 1 OE-1 0 std eels) which were eventually stopped by thread tightening, gasket replacement. redesign, etc. The ROR method helped measure the leakage past valve plugs and establish outgassing rates for volumes deemed as being tight; ie, no detectable leakage using the HMSLD. The throughput calculation was used only to determine the relatively large leak past the plug/seat of the vaporizer valve. A sample calculation of each leakage rate determining method is attached to this note. All leakage rates are given for helium gas at

  5. [Bile leakage in laparoscopic cholecystectomy. Authors' experience].

    PubMed

    Sperlongano, P; Pisaniello, D; Corsale, I; Cozza, G

    1999-01-01

    The Authors report their experience of two patients with bile leakage following videocholecystectomy (VLC) among a series of 163 cases. Reviewing the Literature, they analyze possible causes and mechanisms of bile spillage occurring after VCL. They also suggest some guidelines for a safe VLC, stressing the importance of the routinary placement of the sub-hepatic drainage to remove 48 hours to early detect possible bile leakages after surgery.

  6. Gate leakage mechanisms in strained Si devices

    NASA Astrophysics Data System (ADS)

    Yan, L.; Olsen, S. H.; Kanoun, M.; Agaiby, R.; O'Neill, A. G.

    2006-11-01

    This work investigates gate leakage mechanisms in advanced strained Si /SiGe metal-oxide-semiconductor field-effect transistor (MOSFET) devices. The impact of virtual substrate Ge content, epitaxial material quality, epitaxial layer structure, and device processing on gate oxide leakage characteristics are analyzed in detail. In state of the art MOSFETs, gate oxides are only a few nanometers thick. In order to minimize power consumption, leakage currents through the gate must be controlled. However, modifications to the energy band structure, Ge diffusion due to high temperature processing, and Si /SiGe material quality may all affect gate oxide leakage in strained Si devices. We show that at high oxide electric fields where gate leakage is dominated by Fowler-Nordheim tunneling, tensile strained Si MOSFETs exhibit lower leakage levels compared with bulk Si devices. This is a direct result of strain-induced splitting of the conduction band states. However, for device operating regimes at lower oxide electric fields Poole-Frenkel emissions contribute to strained Si gate leakage and increase with increasing virtual substrate Ge content. The emissions are shown to predominantly originate from surface roughness generating bulk oxide traps, opposed to Ge diffusion, and can be improved by introducing a high temperature anneal. Gate oxide interface trap density exhibits a dissimilar behavior and is highly sensitive to Ge atoms at the oxidizing surface, degrading with increasing thermal budget. Consequently advanced strained Si /SiGe devices are inadvertently subject to a potential tradeoff between power consumption (gate leakage current) and device reliability (gate oxide interface quality).

  7. Measuring Heat-Exchanger Water Leakage

    NASA Technical Reports Server (NTRS)

    Zampiceni, J.

    1986-01-01

    Water leakage in heat exchanger measured directly with help of electroytic hygrometer. In new technique, flow of nitrogen gas set up in one loop of heat exchanger. Other loop filled with water under pressure. Water concentration produced by leakage of water into nitrogen flow measured by hygrometer. New measurement method determines water concentrations up to 2,000 parts per million with accuracy of +/- 5 percent.

  8. Technology evaluation for space station atmospheric leakage

    SciTech Connect

    Lemon, D.K.; Friesel, M.A.; Griffin, J.W.; Skorpik, J.R.; Shepard, C.L.; Antoniak, Z.I.; Kurtz, R.J.

    1990-02-01

    A concern in operation of a space station is leakage of atmosphere through seal points and through the walls as a result of damage from particle (space debris and micrometeoroid) impacts. This report describes a concept for a monitoring system to detect atmosphere leakage and locate the leak point. The concept is based on analysis and testing of two basic methods selected from an initial technology survey of potential approaches. 18 refs., 58 figs., 5 tabs.

  9. Leakage Suppression in the Toric Code

    NASA Astrophysics Data System (ADS)

    Suchara, Martin; Cross, Andrew; Gambetta, Jay

    2015-03-01

    Quantum codes excel at correcting local noise but fail to correct leakage faults that excite qubits to states outside the computational space. Aliferis and Terhal have shown that an accuracy threshold exists for leakage faults using gadgets called leakage reduction units (LRUs). However, these gadgets reduce the threshold and increase experimental complexity, and the costs have not been thoroughly understood. We explore a variety of techniques for leakage resilience in topological codes. Our contributions are threefold. First, we develop a leakage model that differs in critical details from earlier models. Second, we use Monte-Carlo simulations to survey several syndrome extraction circuits. Third, given the capability to perform 3-outcome measurements, we present a dramatically improved syndrome processing algorithm. Our simulations show that simple circuits with one extra CNOT per qubit reduce the accuracy threshold by less than a factor of 4 when leakage and depolarizing noise rates are comparable. This becomes a factor of 2 when the decoder uses 3-outcome measurements. Finally, when the physical error rate is less than 2 ×10-4 , placing LRUs after every gate may achieve the lowest logical error rate. We expect that the ideas may generalize to other topological codes.

  10. EFFECTS OF LEAKAGE NEUTRAL PARTICLES ON SHOCKS

    SciTech Connect

    Ohira, Yutaka

    2012-10-20

    In this paper, we investigate effects of neutral particles on shocks propagating into the partially ionized medium. We find that for 120 km s{sup -1} < u {sub sh} < 3000 km s{sup -1} (u {sub sh} is the shock velocity), about 10% of upstream neutral particles leak into the upstream region from the downstream region. Moreover, we investigate how the leakage neutral particles affect the upstream structure of the shock and particle accelerations. Using four-fluid approximations (upstream ions, upstream neutral particles, leakage neutral particles, and pickup ions), we provide analytical solutions of the precursor structure due to leakage neutral particles. It is shown that the upstream flow is decelerated in the precursor region and the shock compression ratio becomes smaller than without leakage neutral particles, but the total compression ratio does not change. Even if leakage of neutral particles is small (a few percent of total upstream particles), this smaller compression ratio of the shock can explain steep gamma-ray spectra from young supernova remnants. Furthermore, leakage neutral particles could amplify the magnetic field and heat the upstream region.

  11. Heparin Leakage in Central Venous Catheters by Hemodynamic Transport

    NASA Astrophysics Data System (ADS)

    Barbour, Michael; McGah, Patrick; Gow, Kenneth; Aliseda, Alberto

    2014-11-01

    Central venous catheters (CVCs), placed in the superior vena cava for hemodialysis, are routinely filled with heparin, an anticoagulant, while not in use to maintain patency and prevent thrombus formation at the catheter tip. However, the heparin-lock procedure places the patient at risk for systemic bleeding incidences, as heparin is known to leak into the blood stream. We propose that the driving mechanism behind heparin leakage is advective-diffusive transport due to the pulsatile blood flow surrounding the catheter tip. This novel hypothesis is based on Planar Laser Induced Fluorescence (PLIF) measurements of heparin transport from a CVC placed inside an in vitro pulsatile flow loop and validated with CFD simulations. The results show an initial, fast (<10s), advection-dominated phase that rapidly depletes the concentration of heparin at the CVC tip, followed by a slow, diffusion-limited phase inside the catheter lumen, where concentration is still high, that is insufficient at replenishing the lost heparin at the tip. These results, which estimate leakage rates consistent with published in vivo data, predict that the concentration of heparin at the catheter tip is effectively zero for the majority of the interdialytic phase, rendering the heparin lock ineffective.

  12. 40 CFR 264.252 - Action leakage rate.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 26 2011-07-01 2011-07-01 false Action leakage rate. 264.252 Section... Piles § 264.252 Action leakage rate. (a) The Regional Administrator shall approve an action leakage rate for waste pile units subject to § 264.251(c) or (d). The action leakage rate is the maximum...

  13. 40 CFR 264.252 - Action leakage rate.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 27 2013-07-01 2013-07-01 false Action leakage rate. 264.252 Section... Piles § 264.252 Action leakage rate. (a) The Regional Administrator shall approve an action leakage rate for waste pile units subject to § 264.251(c) or (d). The action leakage rate is the maximum...

  14. 49 CFR 192.706 - Transmission lines: Leakage surveys.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 49 Transportation 3 2014-10-01 2014-10-01 false Transmission lines: Leakage surveys. 192.706... Transmission lines: Leakage surveys. Leakage surveys of a transmission line must be conducted at intervals not... transports gas in conformity with § 192.625 without an odor or odorant, leakage surveys using leak...

  15. 40 CFR 264.222 - Action leakage rate.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 26 2014-07-01 2014-07-01 false Action leakage rate. 264.222 Section... Impoundments § 264.222 Action leakage rate. (a) The Regional Administrator shall approve an action leakage rate for surface impoundment units subject to § 264.221 (c) or (d). The action leakage rate is the...

  16. 40 CFR 264.252 - Action leakage rate.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 27 2012-07-01 2012-07-01 false Action leakage rate. 264.252 Section... Piles § 264.252 Action leakage rate. (a) The Regional Administrator shall approve an action leakage rate for waste pile units subject to § 264.251(c) or (d). The action leakage rate is the maximum...

  17. 49 CFR 192.723 - Distribution systems: Leakage surveys.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 49 Transportation 3 2013-10-01 2013-10-01 false Distribution systems: Leakage surveys. 192.723... Distribution systems: Leakage surveys. (a) Each operator of a distribution system shall conduct periodic leakage surveys in accordance with this section. (b) The type and scope of the leakage control...

  18. 40 CFR 264.252 - Action leakage rate.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 25 2010-07-01 2010-07-01 false Action leakage rate. 264.252 Section... Piles § 264.252 Action leakage rate. (a) The Regional Administrator shall approve an action leakage rate for waste pile units subject to § 264.251(c) or (d). The action leakage rate is the maximum...

  19. 40 CFR 264.222 - Action leakage rate.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 27 2012-07-01 2012-07-01 false Action leakage rate. 264.222 Section... Impoundments § 264.222 Action leakage rate. (a) The Regional Administrator shall approve an action leakage rate for surface impoundment units subject to § 264.221 (c) or (d). The action leakage rate is the...

  20. 49 CFR 192.723 - Distribution systems: Leakage surveys.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 3 2010-10-01 2010-10-01 false Distribution systems: Leakage surveys. 192.723... Distribution systems: Leakage surveys. (a) Each operator of a distribution system shall conduct periodic leakage surveys in accordance with this section. (b) The type and scope of the leakage control...

  1. 40 CFR 264.302 - Action leakage rate.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 26 2014-07-01 2014-07-01 false Action leakage rate. 264.302 Section... § 264.302 Action leakage rate. (a) The Regional Administrator shall approve an action leakage rate for landfill units subject to § 264.301(c) or (d). The action leakage rate is the maximum design flow rate...

  2. 40 CFR 264.252 - Action leakage rate.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 26 2014-07-01 2014-07-01 false Action leakage rate. 264.252 Section... Piles § 264.252 Action leakage rate. (a) The Regional Administrator shall approve an action leakage rate for waste pile units subject to § 264.251(c) or (d). The action leakage rate is the maximum...

  3. 49 CFR 192.723 - Distribution systems: Leakage surveys.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 49 Transportation 3 2012-10-01 2012-10-01 false Distribution systems: Leakage surveys. 192.723... Distribution systems: Leakage surveys. (a) Each operator of a distribution system shall conduct periodic leakage surveys in accordance with this section. (b) The type and scope of the leakage control...

  4. 40 CFR 264.222 - Action leakage rate.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 26 2011-07-01 2011-07-01 false Action leakage rate. 264.222 Section... Impoundments § 264.222 Action leakage rate. (a) The Regional Administrator shall approve an action leakage rate for surface impoundment units subject to § 264.221 (c) or (d). The action leakage rate is the...

  5. 40 CFR 264.222 - Action leakage rate.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 25 2010-07-01 2010-07-01 false Action leakage rate. 264.222 Section... Impoundments § 264.222 Action leakage rate. (a) The Regional Administrator shall approve an action leakage rate for surface impoundment units subject to § 264.221 (c) or (d). The action leakage rate is the...

  6. 49 CFR 192.723 - Distribution systems: Leakage surveys.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 3 2011-10-01 2011-10-01 false Distribution systems: Leakage surveys. 192.723... Distribution systems: Leakage surveys. (a) Each operator of a distribution system shall conduct periodic leakage surveys in accordance with this section. (b) The type and scope of the leakage control...

  7. 49 CFR 192.706 - Transmission lines: Leakage surveys.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 49 Transportation 3 2012-10-01 2012-10-01 false Transmission lines: Leakage surveys. 192.706... Transmission lines: Leakage surveys. Leakage surveys of a transmission line must be conducted at intervals not... transports gas in conformity with § 192.625 without an odor or odorant, leakage surveys using leak...

  8. 40 CFR 264.222 - Action leakage rate.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 27 2013-07-01 2013-07-01 false Action leakage rate. 264.222 Section... Impoundments § 264.222 Action leakage rate. (a) The Regional Administrator shall approve an action leakage rate for surface impoundment units subject to § 264.221 (c) or (d). The action leakage rate is the...

  9. 49 CFR 192.706 - Transmission lines: Leakage surveys.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 3 2011-10-01 2011-10-01 false Transmission lines: Leakage surveys. 192.706... Transmission lines: Leakage surveys. Leakage surveys of a transmission line must be conducted at intervals not... transports gas in conformity with § 192.625 without an odor or odorant, leakage surveys using leak...

  10. 49 CFR 192.723 - Distribution systems: Leakage surveys.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 49 Transportation 3 2014-10-01 2014-10-01 false Distribution systems: Leakage surveys. 192.723... Distribution systems: Leakage surveys. (a) Each operator of a distribution system shall conduct periodic leakage surveys in accordance with this section. (b) The type and scope of the leakage control...

  11. 40 CFR 264.302 - Action leakage rate.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 26 2011-07-01 2011-07-01 false Action leakage rate. 264.302 Section... § 264.302 Action leakage rate. (a) The Regional Administrator shall approve an action leakage rate for landfill units subject to § 264.301(c) or (d). The action leakage rate is the maximum design flow rate...

  12. 40 CFR 264.302 - Action leakage rate.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 27 2013-07-01 2013-07-01 false Action leakage rate. 264.302 Section... § 264.302 Action leakage rate. (a) The Regional Administrator shall approve an action leakage rate for landfill units subject to § 264.301(c) or (d). The action leakage rate is the maximum design flow rate...

  13. 40 CFR 264.302 - Action leakage rate.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 27 2012-07-01 2012-07-01 false Action leakage rate. 264.302 Section... § 264.302 Action leakage rate. (a) The Regional Administrator shall approve an action leakage rate for landfill units subject to § 264.301(c) or (d). The action leakage rate is the maximum design flow rate...

  14. 40 CFR 264.302 - Action leakage rate.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 25 2010-07-01 2010-07-01 false Action leakage rate. 264.302 Section... § 264.302 Action leakage rate. (a) The Regional Administrator shall approve an action leakage rate for landfill units subject to § 264.301(c) or (d). The action leakage rate is the maximum design flow rate...

  15. 21 CFR 870.2640 - Portable leakage current alarm.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Portable leakage current alarm. 870.2640 Section... leakage current alarm. (a) Identification. A portable leakage current alarm is a device used to measure the electrical leakage current between any two points of an electrical system and to sound an alarm...

  16. 49 CFR 192.706 - Transmission lines: Leakage surveys.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 49 Transportation 3 2013-10-01 2013-10-01 false Transmission lines: Leakage surveys. 192.706... Transmission lines: Leakage surveys. Leakage surveys of a transmission line must be conducted at intervals not... transports gas in conformity with § 192.625 without an odor or odorant, leakage surveys using leak...

  17. Determination of leakage areas in nuclear piping

    SciTech Connect

    Keim, E.

    1997-04-01

    For the design and operation of nuclear power plants the Leak-Before-Break (LBB) behavior of a piping component has to be shown. This means that the length of a crack resulting in a leak is smaller than the critical crack length and that the leak is safely detectable by a suitable monitoring system. The LBB-concept of Siemens/KWU is based on computer codes for the evaluation of critical crack lengths, crack openings, leakage areas and leakage rates, developed by Siemens/KWU. In the experience with the leak rate program is described while this paper deals with the computation of crack openings and leakage areas of longitudinal and circumferential cracks by means of fracture mechanics. The leakage areas are determined by the integration of the crack openings along the crack front, considering plasticity and geometrical effects. They are evaluated with respect to minimum values for the design of leak detection systems, and maximum values for controlling jet and reaction forces. By means of fracture mechanics LBB for subcritical cracks has to be shown and the calculation of leakage areas is the basis for quantitatively determining the discharge rate of leaking subcritical through-wall cracks. The analytical approach and its validation will be presented for two examples of complex structures. The first one is a pipe branch containing a circumferential crack and the second one is a pipe bend with a longitudinal crack.

  18. Sustainable management of leakage from wastewater pipelines.

    PubMed

    DeSilva, D; Burn, S; Tjandraatmadja, G; Moglia, M; Davis, P; Wolf, L; Held, I; Vollertsen, J; Williams, W; Hafskjold, L

    2005-01-01

    Wastewater pipeline leakage is an emerging concern in Europe, especially with regards to the potential effect of leaking effluent on groundwater contamination and the effects infiltration has on the management of sewer reticulation systems. This paper describes efforts by Australia, in association with several European partners, towards the development of decision support tools to prioritize proactive rehabilitation of wastewater pipe networks to account for leakage. In the fundamental models for the decision support system, leakage is viewed as a function of pipeline system deterioration. The models rely on soil type identification across the service area to determine the aggressiveness of the pipe environment and for division of the area into zones based on pipe properties and operational conditions. By understanding the interaction between pipe materials, operating conditions, and the pipe environment in the mechanisms leading to pipe deterioration, the models allow the prediction of leakage rates in different zones across a network. The decision support system utilizes these models to predict the condition of pipes in individual zones, and to optimize the utilization of rehabilitation resources by targeting the areas with the highest leakage rates.

  19. Leakage Sign for Primary Intracerebral Hemorrhage

    PubMed Central

    Hirohata, Masaru; Nakamura, Yukihiko; Takeshige, Nobuyuki; Aoki, Takachika; Hattori, Gousuke; Sakata, Kiyohiko; Abe, Toshi; Uchiyama, Yuusuke; Sakamoto, Teruo; Morioka, Motohiro

    2016-01-01

    Background and Purpose— Recent studies of intracerebral hemorrhage treatments have highlighted the need to identify reliable predictors of hematoma expansion. Several studies have suggested that the spot sign on computed tomographic angiography (CTA) is a sensitive radiological predictor of hematoma expansion in the acute phase. However, the spot sign has low sensitivity for hematoma expansion. In this study, we evaluated the usefulness of a novel predictive method, called the leakage sign. Methods— We performed CTA for 80 consecutive patients presenting with spontaneous intracerebral hemorrhage. Two scans were completed: CTA phase and delayed phase (5 minutes after the CTA phase). By comparing the CTA phase images, we set a region of interest with a 10-mm diameter and calculated the Hounsfield units. We defined a positive leakage sign as a >10% increase in Hounsfield units in the region of interest. Additionally, hematoma expansion was determined on plain computed tomography at 24 hours in patients who did not undergo emergent surgery. Results— Positive spot signs and leakage signs were present in 18 (22%) patients and 35 (43%) patients, respectively. The leakage sign had higher sensitivity (93.3%) and specificity (88.9%) for hematoma expansion than the spot sign. The leakage sign, but not the spot sign, was significantly related with poor outcomes (severely disabled, vegetative state, and death) in all of the patients (P=0.03) and in patients with a hemorrhage in the putamen (P=0.0016). Conclusions— The results indicate that the leakage sign is a useful and sensitive method to predict hematoma expansion. PMID:26931155

  20. Inward leakage in tight-fitting PAPRs.

    PubMed

    Koh, Frank C; Johnson, Arthur T; Rehak, Timothy E

    2011-01-01

    A combination of local flow measurement techniques and fog flow visualization was used to determine the inward leakage for two tight-fitting powered air-purifying respirators (PAPRs), the 3M Breathe-Easy PAPR and the SE 400 breathing demand PAPR. The PAPRs were mounted on a breathing machine head form, and flows were measured from the blower and into the breathing machine. Both respirators leaked a little at the beginning of inhalation, probably through their exhalation valves. In both cases, the leakage was not enough for fog to appear at the mouth of the head form.

  1. Air heater leakage: worse than you think

    SciTech Connect

    Guffre, J.

    2006-04-15

    Every good engineer knows that you cannot control what you cannot measure. In the case of rotary regenerative air heaters, many plants fail to limit the negative impact of heater leakage because they use measurement procedures and/or devices that fail to take into account its indirect effects. For a 500 MW coal-fired plant the heat energy that air heaters capture and recycle amounts to about 60% of that existing in the boiler, equivalent to 1.5 Btu per hour. This article explains the importance of accurately measuring leakage levels and the need to use modern seals to make heaters air-tight. 4 figs.

  2. Inward Leakage in Tight-Fitting PAPRs

    PubMed Central

    Koh, Frank C.; Johnson, Arthur T.; Rehak, Timothy E.

    2011-01-01

    A combination of local flow measurement techniques and fog flow visualization was used to determine the inward leakage for two tight-fitting powered air-purifying respirators (PAPRs), the 3M Breathe-Easy PAPR and the SE 400 breathing demand PAPR. The PAPRs were mounted on a breathing machine head form, and flows were measured from the blower and into the breathing machine. Both respirators leaked a little at the beginning of inhalation, probably through their exhalation valves. In both cases, the leakage was not enough for fog to appear at the mouth of the head form. PMID:21647352

  3. Is the Aluminum Hypothesis Dead?

    PubMed Central

    2014-01-01

    The Aluminum Hypothesis, the idea that aluminum exposure is involved in the etiology of Alzheimer disease, dates back to a 1965 demonstration that aluminum causes neurofibrillary tangles in the brains of rabbits. Initially the focus of intensive research, the Aluminum Hypothesis has gradually been abandoned by most researchers. Yet, despite this current indifference, the Aluminum Hypothesis continues to attract the attention of a small group of scientists and aluminum continues to be viewed with concern by some of the public. This review article discusses reasons that mainstream science has largely abandoned the Aluminum Hypothesis and explores a possible reason for some in the general public continuing to view aluminum with mistrust. PMID:24806729

  4. Is the Aluminum Hypothesis dead?

    PubMed

    Lidsky, Theodore I

    2014-05-01

    The Aluminum Hypothesis, the idea that aluminum exposure is involved in the etiology of Alzheimer disease, dates back to a 1965 demonstration that aluminum causes neurofibrillary tangles in the brains of rabbits. Initially the focus of intensive research, the Aluminum Hypothesis has gradually been abandoned by most researchers. Yet, despite this current indifference, the Aluminum Hypothesis continues to attract the attention of a small group of scientists and aluminum continues to be viewed with concern by some of the public. This review article discusses reasons that mainstream science has largely abandoned the Aluminum Hypothesis and explores a possible reason for some in the general public continuing to view aluminum with mistrust.

  5. Management of long-term persistent air leakage developed after bullectomy for giant bullous lung disease associated with neurofibromatosis type 1.

    PubMed

    Kim, Si-Wook; Kim, Dohun

    2016-01-01

    Persistent air leakage is a serious and sometimes fatal complication of bullous lung disease surgery. A 32-year-old man with lung involvement of neurofibromatosis type I underwent bullectomy for huge bullae and recurrent pneumothorax. Persistent postoperative air leakage developed and the lung was totally collapsed. The initial surgery failed, but a second trial employing a novel suture technique on half-absorbed polyglycolic acid (PGA) felt successfully resolved the massive air leakage. Pneumothorax did not recur and the patient remained stable without dyspnea. Thus, a suture technique employing half-absorbed PGA felt was an effective option for managing persistent air leakage.

  6. Management of long-term persistent air leakage developed after bullectomy for giant bullous lung disease associated with neurofibromatosis type 1

    PubMed Central

    Kim, Si-Wook

    2016-01-01

    Persistent air leakage is a serious and sometimes fatal complication of bullous lung disease surgery. A 32-year-old man with lung involvement of neurofibromatosis type I underwent bullectomy for huge bullae and recurrent pneumothorax. Persistent postoperative air leakage developed and the lung was totally collapsed. The initial surgery failed, but a second trial employing a novel suture technique on half-absorbed polyglycolic acid (PGA) felt successfully resolved the massive air leakage. Pneumothorax did not recur and the patient remained stable without dyspnea. Thus, a suture technique employing half-absorbed PGA felt was an effective option for managing persistent air leakage. PMID:26904244

  7. Measurements of the atmospheric neutron leakage rate

    NASA Technical Reports Server (NTRS)

    Lockwood, J. A.; Ifedili, S. O.; Jenkins, R. W.

    1973-01-01

    The atmospheric neutron leakage rate in the energy range from 0.01 to 10,000,000 eV has been measured as a function of latitude, altitude, and time with a neutron detector on board the Ogo 6 satellite. The latitude dependence of the neutron leakage is in reasonable agreement with that predicted by Lingenfelter (1963) and Light et al. (1973) if the neutron energy spectrum has the shape calculated by Newkirk (1963). The change in the neutron latitude dependence with the cosmic ray modulation agrees with the predictions of Lingenfelter and Light et al. For several solar proton events enhancements were observed in the neutron counting rates at lambda greater than or equal to 70 deg. Such events, however, provide an insignificant injection of protons at E less than or equal to 20 MeV into the radiation belts. An isotropic angular distribution of the neutron leakage in the energy range from 0.1 keV to 10 MeV best fits the observed altitude dependence of the neutron leakage flux.

  8. Control of Air Leakage in Buildings.

    ERIC Educational Resources Information Center

    Wilson, A. Grant

    This discussion of air leakage emphasizes cause and provides suggestions for elimination of undesirable effects. Cause parameters described are--(1) pressure differential, (2) building shape, (3) temperature differential, (4) opening sizes, (5) mechanical system pressures, and (6) climatic factors. Effects discussed are--(1) increased mechanical…

  9. Seasonal variation in effective leakage area

    SciTech Connect

    Dickinson, J.B.; Feustel, H.E.

    1986-01-01

    Previous research on the seasonal changes in airtightness has been conducted by other researchers on one or two houses in one location. This paper describes air leakage rate measurements using the fan pressurization technique performed monthly over a period of one year in ten occupied houses in three different climates. The purpose of this study is to determine the seasonal variation in effective leakage area in houses in different climates. The three sets of houses included in this study are located in Reno, Nevada (semi-arid, high desert), Truckee, California (alpine, mountainous), and the San Francisco Bay Area (temperate, coastal). The houses are all wood-frame construction and range from one year to seventy years in age. Indoor and outdoor air temperatures, wind speed, and the moisture content of wood framing and other building components were measured at the time of each fan pressurization test. Indoor moisture levels were monitored by measuring the moisture content of a reference block of wood that was located indoors at each site. The results indicate a seasonal variation in effective leakage area in some but not all of the houses; the largest variations are seen in the Truckee houses with effective leakage areas up to 45% higher in the summer as compared to those measured in midwinter.

  10. Imaging inflammatory plasma leakage in vivo.

    PubMed

    Kenne, E; Lindbom, L

    2011-05-01

    Increased vascular permeability and consequent plasma leakage from postcapillary venules is a cardinal sign of inflammation. Although the movement of plasma constituents from the vasculature to the affected tissue aids in clearing the inflammatory stimulus, excessive plasma extravasation can lead to hospitalisation or death in cases such as influenza-induced pneumonia, burns or brain injury. The use of intravital imaging has significantly contributed to the understanding of the mechanisms controlling the vascular permeability alterations that occur during inflammation. Today, intravital imaging can be performed using optical and non-optical techniques. Optical techniques, which are generally used in experimental settings, include traditional intravital fluorescence microscopy and near-infrared fluorescence imaging. Magnetic resonance (MRI) and radioisotopic imaging are used mainly in the clinical setting, but are increasingly used in experimental work, and can detect plasma leakage without optics. Although these methods are all able to visualise inflammatory plasma leakage in vivo, the spatial and temporal resolution differs between the techniques. In addition, they vary with regards to invasiveness and availability. This overview discusses the use of imaging techniques in the visualisation of inflammatory plasma leakage. PMID:21437352

  11. Reduction of valve leakage - A concept

    NASA Technical Reports Server (NTRS)

    Doshi, N. H.; Salvinski, R. J.

    1971-01-01

    Leakage elimination occurs by increasing pressure on poppet seat, heating poppet plunger or cooling valve body, and then exerting force between 4.45 and 44.5 kN at poppet seat interface. Valves are useful in handling of corrosive fluids.

  12. Pressure Gauges Monitor Leakage Past Seals

    NASA Technical Reports Server (NTRS)

    Smith, Steven A.

    1990-01-01

    Method devised to measure leakage of gas past each of two sets of primary and secondary seals into common volume from which aggregate flow measured. Although method applicable only to specific combination of flow configuration and thermal conditions, it serves as example of more general approach involving use of statistical analysis to extract additional information from measurements.

  13. Bronchial Venular Leakage During Endotoxin Shock

    PubMed Central

    Pietra, G. G.; Szidon, J. P.; Carpenter, H. A.; Fishman, A. P.

    1974-01-01

    The pulmonary effects of endotoxin shock were investigated in dogs by a combination of anatomic and physiologic technics. Shock was produced in 14 dogs by injecting Escherichia coli lipopolysaccharide intravenously. Three dogs in hypovolemic shock and 6 untreated dogs served as controls. Colloidal carbon was injected intravenously to detect sites of pathologic increase in vascular permeability. During the first hour of endotoxin shock, bronchial venules allowed carbon and blood elements to traverse their walls, whereas no leakage of these large particles or ultrastructural changes could be detected in the alveolar walls. Only after the first hour was bronchial venular leakage accompanied by focal degenerative changes in the alveolar endothelium, focal interstitial edema in the alveolar septum and sequestration of damaged leukocytes in the alveolar capillaries. In contrast to these observations in endotoxin shock, control dogs in hypovolemic shock did not show bronchial venous leakage. Our findings suggest that the leakage of bronchial venules may be involved in the pathogenesis of pulmonary interstitial edema caused by endotoxin shock. ImagesFig 2Fig 3Fig 4Fig 1 PMID:4611225

  14. Threshold Hypothesis: Fact or Artifact?

    ERIC Educational Resources Information Center

    Karwowski, Maciej; Gralewski, Jacek

    2013-01-01

    The threshold hypothesis (TH) assumes the existence of complex relations between creative abilities and intelligence: linear associations below 120 points of IQ and weaker or lack of associations above the threshold. However, diverse results have been obtained over the last six decades--some confirmed the hypothesis and some rejected it. In this…

  15. A new hypothesis of drug refractory epilepsy: neural network hypothesis.

    PubMed

    Fang, Min; Xi, Zhi-Qin; Wu, Yuan; Wang, Xue-Feng

    2011-06-01

    Drug refractory is an important clinical problem in epilepsy, affecting a substantial number of patients globally. Mechanisms underlying drug refractory need to be understood to develop rational therapies. Current two prevailing theories on drug refractory epilepsy (DRE) include the target hypothesis and the transporter hypothesis. However, those hypotheses could not be adequate to explain the mechanisms of all the DRE. Thus, we propose another possible mechanism of DRE, which is neural network hypothesis. It is hypothesized that seizure-induced alterations of brain plasticity including axonal sprouting, synaptic reorganization, neurogenesis and gliosis could contribute to the formation of abnormal neural network, which has not only avoided the inhibitory effect of endogenous antiepileptic system but also prevented the traditional antiepileptic drugs from entering their targets, eventually leading to DRE. We will illustrate this hypothesis at molecular and structural level based on our recent studies and other related researches.

  16. 40 CFR 91.324 - Analyzer leakage check.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... Analyzer leakage check. (a) Vacuum side leak check. (1) Check any location within the analysis system where a vacuum leak could affect the test results. (2) The maximum allowable leakage rate on the...

  17. 40 CFR 91.324 - Analyzer leakage check.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... Analyzer leakage check. (a) Vacuum side leak check. (1) Check any location within the analysis system where a vacuum leak could affect the test results. (2) The maximum allowable leakage rate on the...

  18. 40 CFR 91.324 - Analyzer leakage check.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... Analyzer leakage check. (a) Vacuum side leak check. (1) Check any location within the analysis system where a vacuum leak could affect the test results. (2) The maximum allowable leakage rate on the...

  19. 40 CFR 91.324 - Analyzer leakage check.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... Analyzer leakage check. (a) Vacuum side leak check. (1) Check any location within the analysis system where a vacuum leak could affect the test results. (2) The maximum allowable leakage rate on the...

  20. 40 CFR 91.324 - Analyzer leakage check.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... Analyzer leakage check. (a) Vacuum side leak check. (1) Check any location within the analysis system where a vacuum leak could affect the test results. (2) The maximum allowable leakage rate on the...

  1. Reserves in Context: Planning for Leakage from Protected Areas.

    PubMed

    Renwick, Anna R; Bode, Michael; Venter, Oscar

    2015-01-01

    When protected areas reduce threats within their boundaries, they often displace a portion of these threats into adjacent areas through a process known as 'leakage', undermining conservation objectives. Using theoretical models and a case study of terrestrial mammals in Indonesia, we develop the first theoretical explanation of how leakage impacts conservation actions, and highlight conservation strategies that mitigate these impacts. Although leakage is a socio-economic process, we demonstrate that its negative impacts are also affected by the distribution of species, with leakage having larger impacts in landscapes with homogeneous distribution of species richness. Moreover, leakage has a greater negative effect when conservation strategies are implemented opportunistically, even creating the potential for perversely negative consequences from protected area establishment. Leakage thereby increases the relative benefits of systematic conservation planning over opportunism, especially in areas with high leakage and heterogeneously distributed species. Although leakage has the potential to undermine conservation actions, conservation planning can minimize this risk.

  2. Measuring Leakage in a Pressurized-Fluid Loop

    NASA Technical Reports Server (NTRS)

    Clarke, Brian D.

    1987-01-01

    Technique applied to systems with inaccessible parts and connections. Fluid added to system by fluid-injection assembly to make up for leakage. Amount required to restore pressure in system is measure of leakage rate.

  3. Nonlinear Acoustics Used To Reduce Leakage Flow

    NASA Technical Reports Server (NTRS)

    Daniels, Christopher C.; Steinetz, Bruce M.

    2004-01-01

    Leakage and wear are two fundamental problems in all traditional turbine seals that contribute to an engine's inefficiency. The solutions to seal leakage and wear conflict in the conventional design space. Reducing the clearance between the seal and rotating shaft reduces leakage but increases wear because of increased contact incidents. Increasing the clearance to reduce the contact between parts reduces wear but increases parasitic leakage. The goal of this effort is to develop a seal that restricts leakage flow using acoustic pressure while operating in a noncontacting manner, thereby increasing life. In 1996, Dr. Timothy Lucas announced his discovery of a method to produce shock-free high-amplitude pressure waves. For the first time, the formation of large acoustic pressures was possible using dissonant resonators. A pre-prototype acoustic seal developed at the NASA Glenn Research Center exploits this fundamental acoustic discovery: a specially shaped cavity oscillated at the contained fluid's resonant frequency produces high-amplitude acoustic pressure waves of a magnitude approaching those required of today's seals. While the original researchers are continuing their development of acoustic pumps, refrigeration compressors, and electronic thermal management systems using this technology, the goal of researchers at Glenn is to apply these acoustic principles to a revolutionary sealing device. When the acoustic resonator shape is optimized for the sealing device, the flow from a high-pressure cavity to a low-pressure cavity will be restricted by a series of high-amplitude standing pressure waves of higher pressure than the pressure to be sealed. Since the sealing resonator cavity will not touch the adjacent sealing structures, seal wear will be eliminated, improving system life. Under a cooperative agreement between Glenn and the Ohio Aerospace Institute (OAI), an acoustic-based pre-prototype seal was demonstrated for the first time. A pressurized cavity was

  4. Trending of Overboard Leakage of ISS Cabin Atmosphere

    NASA Technical Reports Server (NTRS)

    Schaezler, Ryan N.; Cook, Anthony J.; Leonard, Daniel J.; Ghariani, Ahmed

    2011-01-01

    The International Space Station (ISS) overboard leakage of cabin atmosphere is continually tracked to identify new or aggravated leaks and to provide information for planning of nitrogen supply to the ISS. The overboard leakage is difficult to trend with various atmosphere constituents being added and removed. Changes to nitrogen partial pressure is the nominal means of trending the overboard leakage. This paper summarizes the method of the overboard leakage trending and presents findings from the trending.

  5. Evaluating the Stage Learning Hypothesis.

    ERIC Educational Resources Information Center

    Thomas, Hoben

    1980-01-01

    A procedure for evaluating the Genevan stage learning hypothesis is illustrated by analyzing Inhelder, Sinclair, and Bovet's guided learning experiments (in "Learning and the Development of Cognition." Cambridge: Harvard University Press, 1974). (Author/MP)

  6. 49 CFR 178.345-13 - Pressure and leakage tests.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 3 2011-10-01 2011-10-01 false Pressure and leakage tests. 178.345-13 Section 178... Specifications for Containers for Motor Vehicle Transportation § 178.345-13 Pressure and leakage tests. (a) Each cargo tank must be pressure and leakage tested in accordance with this section and §§ 178.346-5,...

  7. 49 CFR 178.345-13 - Pressure and leakage tests.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 2 2010-10-01 2010-10-01 false Pressure and leakage tests. 178.345-13 Section 178... PACKAGINGS Specifications for Containers for Motor Vehicle Transportation § 178.345-13 Pressure and leakage tests. (a) Each cargo tank must be pressure and leakage tested in accordance with this section...

  8. 49 CFR 178.345-13 - Pressure and leakage tests.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 49 Transportation 3 2012-10-01 2012-10-01 false Pressure and leakage tests. 178.345-13 Section 178... Specifications for Containers for Motor Vehicle Transportation § 178.345-13 Pressure and leakage tests. (a) Each cargo tank must be pressure and leakage tested in accordance with this section and §§ 178.346-5,...

  9. 49 CFR 178.345-13 - Pressure and leakage tests.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 49 Transportation 3 2014-10-01 2014-10-01 false Pressure and leakage tests. 178.345-13 Section 178... Specifications for Containers for Motor Vehicle Transportation § 178.345-13 Pressure and leakage tests. (a) Each cargo tank must be pressure and leakage tested in accordance with this section and §§ 178.346-5,...

  10. 49 CFR 178.345-13 - Pressure and leakage tests.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 49 Transportation 3 2013-10-01 2013-10-01 false Pressure and leakage tests. 178.345-13 Section 178... Specifications for Containers for Motor Vehicle Transportation § 178.345-13 Pressure and leakage tests. (a) Each cargo tank must be pressure and leakage tested in accordance with this section and §§ 178.346-5,...

  11. 42 CFR 84.92 - Exhalation valve leakage test.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 42 Public Health 1 2011-10-01 2011-10-01 false Exhalation valve leakage test. 84.92 Section 84.92... Breathing Apparatus § 84.92 Exhalation valve leakage test. (a) Dry exhalation valves and valve seats will be...) Leakage between the valve and the valve seat shall not exceed 30 milliliters per minute....

  12. 42 CFR 84.123 - Exhalation valve leakage test.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 42 Public Health 1 2010-10-01 2010-10-01 false Exhalation valve leakage test. 84.123 Section 84....123 Exhalation valve leakage test. (a) Dry exhalation valves and valve seats will be subjected to a suction of 25 mm. water-column height while in a normal operating position. (b) Leakage between the...

  13. 42 CFR 84.92 - Exhalation valve leakage test.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 42 Public Health 1 2010-10-01 2010-10-01 false Exhalation valve leakage test. 84.92 Section 84.92... Breathing Apparatus § 84.92 Exhalation valve leakage test. (a) Dry exhalation valves and valve seats will be...) Leakage between the valve and the valve seat shall not exceed 30 milliliters per minute....

  14. 42 CFR 84.123 - Exhalation valve leakage test.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 42 Public Health 1 2011-10-01 2011-10-01 false Exhalation valve leakage test. 84.123 Section 84....123 Exhalation valve leakage test. (a) Dry exhalation valves and valve seats will be subjected to a suction of 25 mm. water-column height while in a normal operating position. (b) Leakage between the...

  15. 46 CFR 98.30-17 - Leakage containment.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 4 2014-10-01 2014-10-01 false Leakage containment. 98.30-17 Section 98.30-17 Shipping... Intermediate Bulk Containers § 98.30-17 Leakage containment. (a) No person may transfer a product to or from a... or more and must have a means of draining or removing any leakage without mixing...

  16. 47 CFR 76.1804 - Aeronautical frequencies: leakage monitoring (CLI).

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 47 Telecommunication 4 2013-10-01 2013-10-01 false Aeronautical frequencies: leakage monitoring... Aeronautical frequencies: leakage monitoring (CLI). An MVPD shall notify the Commission before transmitting any... to be used; and (g) For MVPDs subject to § 76.611, the cumulative signal leakage index derived...

  17. 47 CFR 76.1803 - Signal leakage monitoring.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 47 Telecommunication 4 2012-10-01 2012-10-01 false Signal leakage monitoring. 76.1803 Section 76... MULTICHANNEL VIDEO AND CABLE TELEVISION SERVICE Reports and Filings § 76.1803 Signal leakage monitoring. MVPDs... of the method by which compliance with basic signal leakage criteria is achieved and the method...

  18. 46 CFR 98.30-15 - Leakage containment.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 4 2013-10-01 2013-10-01 false Leakage containment. 98.30-15 Section 98.30-15 Shipping... Leakage containment. (a) No person may transfer a product to or from a vessel unless there is a container... draining or removing any leakage without mixing incompatible products or discharging into the...

  19. 30 CFR 57.4102 - Spillage and leakage.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 30 Mineral Resources 1 2012-07-01 2012-07-01 false Spillage and leakage. 57.4102 Section 57.4102... Control Prohibitions/precautions/housekeeping § 57.4102 Spillage and leakage. Flammable or combustible liquid spillage or leakage shall be removed in a timely manner or controlled to prevent a fire hazard....

  20. 49 CFR 174.750 - Incidents involving leakage.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 49 Transportation 2 2014-10-01 2014-10-01 false Incidents involving leakage. 174.750 Section 174... Detailed Requirements for Class 7 (Radioactive) Materials § 174.750 Incidents involving leakage. (a) In... case of obvious leakage, or if it appears likely that the inside container may have been damaged,...

  1. 40 CFR 265.302 - Action leakage rate.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 26 2014-07-01 2014-07-01 false Action leakage rate. 265.302 Section... FACILITIES Landfills § 265.302 Action leakage rate. (a) The owner or operator of landfill units subject to § 265.301(a) must submit a proposed action leakage rate to the Regional Administrator when...

  2. 49 CFR 174.750 - Incidents involving leakage.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 2 2011-10-01 2011-10-01 false Incidents involving leakage. 174.750 Section 174... Detailed Requirements for Class 7 (Radioactive) Materials § 174.750 Incidents involving leakage. (a) In... case of obvious leakage, or if it appears likely that the inside container may have been damaged,...

  3. 47 CFR 76.1804 - Aeronautical frequencies: leakage monitoring (CLI).

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 47 Telecommunication 4 2011-10-01 2011-10-01 false Aeronautical frequencies: leakage monitoring... Aeronautical frequencies: leakage monitoring (CLI). An MVPD shall notify the Commission before transmitting any... to be used; and (g) For MVPDs subject to § 76.611, the cumulative signal leakage index derived...

  4. 40 CFR 265.302 - Action leakage rate.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 26 2011-07-01 2011-07-01 false Action leakage rate. 265.302 Section... FACILITIES Landfills § 265.302 Action leakage rate. (a) The owner or operator of landfill units subject to § 265.301(a) must submit a proposed action leakage rate to the Regional Administrator when...

  5. 42 CFR 84.92 - Exhalation valve leakage test.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 42 Public Health 1 2014-10-01 2014-10-01 false Exhalation valve leakage test. 84.92 Section 84.92... Breathing Apparatus § 84.92 Exhalation valve leakage test. (a) Dry exhalation valves and valve seats will be...) Leakage between the valve and the valve seat shall not exceed 30 milliliters per minute....

  6. 30 CFR 56.4102 - Spillage and leakage.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 30 Mineral Resources 1 2012-07-01 2012-07-01 false Spillage and leakage. 56.4102 Section 56.4102... Control Prohibitions/precautions/housekeeping § 56.4102 Spillage and leakage. Flammable or combustible liquid spillage or leakage shall be removed in a timely manner or controlled to prevent a fire hazard....

  7. 40 CFR 265.222 - Action leakage rate.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 27 2012-07-01 2012-07-01 false Action leakage rate. 265.222 Section... FACILITIES Surface Impoundments § 265.222 Action leakage rate. (a) The owner or operator of surface impoundment units subject to § 265.221(a) must submit a proposed action leakage rate to the...

  8. 30 CFR 56.4102 - Spillage and leakage.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 30 Mineral Resources 1 2011-07-01 2011-07-01 false Spillage and leakage. 56.4102 Section 56.4102... Control Prohibitions/precautions/housekeeping § 56.4102 Spillage and leakage. Flammable or combustible liquid spillage or leakage shall be removed in a timely manner or controlled to prevent a fire hazard....

  9. 30 CFR 57.4102 - Spillage and leakage.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Spillage and leakage. 57.4102 Section 57.4102... Control Prohibitions/precautions/housekeeping § 57.4102 Spillage and leakage. Flammable or combustible liquid spillage or leakage shall be removed in a timely manner or controlled to prevent a fire hazard....

  10. 46 CFR 98.30-15 - Leakage containment.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 4 2010-10-01 2010-10-01 false Leakage containment. 98.30-15 Section 98.30-15 Shipping... Leakage containment. (a) No person may transfer a product to or from a vessel unless there is a container... draining or removing any leakage without mixing incompatible products or discharging into the water....

  11. 40 CFR 265.302 - Action leakage rate.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 27 2013-07-01 2013-07-01 false Action leakage rate. 265.302 Section... FACILITIES Landfills § 265.302 Action leakage rate. (a) The owner or operator of landfill units subject to § 265.301(a) must submit a proposed action leakage rate to the Regional Administrator when...

  12. 46 CFR 98.30-15 - Leakage containment.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 4 2012-10-01 2012-10-01 false Leakage containment. 98.30-15 Section 98.30-15 Shipping... Leakage containment. (a) No person may transfer a product to or from a vessel unless there is a container... draining or removing any leakage without mixing incompatible products or discharging into the water....

  13. 47 CFR 76.1803 - Signal leakage monitoring.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 47 Telecommunication 4 2014-10-01 2014-10-01 false Signal leakage monitoring. 76.1803 Section 76... MULTICHANNEL VIDEO AND CABLE TELEVISION SERVICE Reports and Filings § 76.1803 Signal leakage monitoring. MVPDs... of the method by which compliance with basic signal leakage criteria is achieved and the method...

  14. 42 CFR 84.123 - Exhalation valve leakage test.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 42 Public Health 1 2013-10-01 2013-10-01 false Exhalation valve leakage test. 84.123 Section 84....123 Exhalation valve leakage test. (a) Dry exhalation valves and valve seats will be subjected to a suction of 25 mm. water-column height while in a normal operating position. (b) Leakage between the...

  15. 42 CFR 84.123 - Exhalation valve leakage test.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 42 Public Health 1 2014-10-01 2014-10-01 false Exhalation valve leakage test. 84.123 Section 84....123 Exhalation valve leakage test. (a) Dry exhalation valves and valve seats will be subjected to a suction of 25 mm. water-column height while in a normal operating position. (b) Leakage between the...

  16. 40 CFR 265.255 - Action leakage rates.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 26 2014-07-01 2014-07-01 false Action leakage rates. 265.255 Section... FACILITIES Waste Piles § 265.255 Action leakage rates. (a) The owner or operator of waste pile units subject to § 265.254 must submit a proposed action leakage rate to the Regional Administrator when...

  17. 40 CFR 265.222 - Action leakage rate.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 25 2010-07-01 2010-07-01 false Action leakage rate. 265.222 Section... FACILITIES Surface Impoundments § 265.222 Action leakage rate. (a) The owner or operator of surface impoundment units subject to § 265.221(a) must submit a proposed action leakage rate to the...

  18. 40 CFR 265.222 - Action leakage rate.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 27 2013-07-01 2013-07-01 false Action leakage rate. 265.222 Section... FACILITIES Surface Impoundments § 265.222 Action leakage rate. (a) The owner or operator of surface impoundment units subject to § 265.221(a) must submit a proposed action leakage rate to the...

  19. 30 CFR 56.4102 - Spillage and leakage.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 30 Mineral Resources 1 2013-07-01 2013-07-01 false Spillage and leakage. 56.4102 Section 56.4102... Control Prohibitions/precautions/housekeeping § 56.4102 Spillage and leakage. Flammable or combustible liquid spillage or leakage shall be removed in a timely manner or controlled to prevent a fire hazard....

  20. 49 CFR 174.750 - Incidents involving leakage.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 49 Transportation 2 2012-10-01 2012-10-01 false Incidents involving leakage. 174.750 Section 174... Detailed Requirements for Class 7 (Radioactive) Materials § 174.750 Incidents involving leakage. (a) In... case of obvious leakage, or if it appears likely that the inside container may have been damaged,...

  1. 40 CFR 265.255 - Action leakage rates.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 25 2010-07-01 2010-07-01 false Action leakage rates. 265.255 Section... FACILITIES Waste Piles § 265.255 Action leakage rates. (a) The owner or operator of waste pile units subject to § 265.254 must submit a proposed action leakage rate to the Regional Administrator when...

  2. 47 CFR 76.1804 - Aeronautical frequencies: leakage monitoring (CLI).

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 47 Telecommunication 4 2010-10-01 2010-10-01 false Aeronautical frequencies: leakage monitoring... Aeronautical frequencies: leakage monitoring (CLI). An MVPD shall notify the Commission before transmitting any... to be used; and (g) For MVPDs subject to § 76.611, the cumulative signal leakage index derived...

  3. 46 CFR 98.30-15 - Leakage containment.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 4 2011-10-01 2011-10-01 false Leakage containment. 98.30-15 Section 98.30-15 Shipping... Leakage containment. (a) No person may transfer a product to or from a vessel unless there is a container... draining or removing any leakage without mixing incompatible products or discharging into the water....

  4. 49 CFR 174.750 - Incidents involving leakage.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 2 2010-10-01 2010-10-01 false Incidents involving leakage. 174.750 Section 174... Detailed Requirements for Class 7 (Radioactive) Materials § 174.750 Incidents involving leakage. (a) In... case of obvious leakage, or if it appears likely that the inside container may have been damaged,...

  5. 30 CFR 56.4102 - Spillage and leakage.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Spillage and leakage. 56.4102 Section 56.4102... Control Prohibitions/precautions/housekeeping § 56.4102 Spillage and leakage. Flammable or combustible liquid spillage or leakage shall be removed in a timely manner or controlled to prevent a fire hazard....

  6. 40 CFR 265.255 - Action leakage rates.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 27 2012-07-01 2012-07-01 false Action leakage rates. 265.255 Section... FACILITIES Waste Piles § 265.255 Action leakage rates. (a) The owner or operator of waste pile units subject to § 265.254 must submit a proposed action leakage rate to the Regional Administrator when...

  7. 30 CFR 57.4102 - Spillage and leakage.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 30 Mineral Resources 1 2013-07-01 2013-07-01 false Spillage and leakage. 57.4102 Section 57.4102... Control Prohibitions/precautions/housekeeping § 57.4102 Spillage and leakage. Flammable or combustible liquid spillage or leakage shall be removed in a timely manner or controlled to prevent a fire hazard....

  8. 49 CFR 174.750 - Incidents involving leakage.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 49 Transportation 2 2013-10-01 2013-10-01 false Incidents involving leakage. 174.750 Section 174... Detailed Requirements for Class 7 (Radioactive) Materials § 174.750 Incidents involving leakage. (a) In... case of obvious leakage, or if it appears likely that the inside container may have been damaged,...

  9. 47 CFR 76.1803 - Signal leakage monitoring.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 47 Telecommunication 4 2013-10-01 2013-10-01 false Signal leakage monitoring. 76.1803 Section 76... MULTICHANNEL VIDEO AND CABLE TELEVISION SERVICE Reports and Filings § 76.1803 Signal leakage monitoring. MVPDs... of the method by which compliance with basic signal leakage criteria is achieved and the method...

  10. 30 CFR 57.4102 - Spillage and leakage.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 30 Mineral Resources 1 2011-07-01 2011-07-01 false Spillage and leakage. 57.4102 Section 57.4102... Control Prohibitions/precautions/housekeeping § 57.4102 Spillage and leakage. Flammable or combustible liquid spillage or leakage shall be removed in a timely manner or controlled to prevent a fire hazard....

  11. 30 CFR 56.4102 - Spillage and leakage.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 30 Mineral Resources 1 2014-07-01 2014-07-01 false Spillage and leakage. 56.4102 Section 56.4102... Control Prohibitions/precautions/housekeeping § 56.4102 Spillage and leakage. Flammable or combustible liquid spillage or leakage shall be removed in a timely manner or controlled to prevent a fire hazard....

  12. 40 CFR 265.255 - Action leakage rates.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 26 2011-07-01 2011-07-01 false Action leakage rates. 265.255 Section... FACILITIES Waste Piles § 265.255 Action leakage rates. (a) The owner or operator of waste pile units subject to § 265.254 must submit a proposed action leakage rate to the Regional Administrator when...

  13. 40 CFR 265.222 - Action leakage rate.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 26 2011-07-01 2011-07-01 false Action leakage rate. 265.222 Section... FACILITIES Surface Impoundments § 265.222 Action leakage rate. (a) The owner or operator of surface impoundment units subject to § 265.221(a) must submit a proposed action leakage rate to the...

  14. 42 CFR 84.123 - Exhalation valve leakage test.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 42 Public Health 1 2012-10-01 2012-10-01 false Exhalation valve leakage test. 84.123 Section 84....123 Exhalation valve leakage test. (a) Dry exhalation valves and valve seats will be subjected to a suction of 25 mm. water-column height while in a normal operating position. (b) Leakage between the...

  15. 40 CFR 265.302 - Action leakage rate.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 27 2012-07-01 2012-07-01 false Action leakage rate. 265.302 Section... FACILITIES Landfills § 265.302 Action leakage rate. (a) The owner or operator of landfill units subject to § 265.301(a) must submit a proposed action leakage rate to the Regional Administrator when...

  16. 47 CFR 76.1804 - Aeronautical frequencies: leakage monitoring (CLI).

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 47 Telecommunication 4 2012-10-01 2012-10-01 false Aeronautical frequencies: leakage monitoring... Aeronautical frequencies: leakage monitoring (CLI). An MVPD shall notify the Commission before transmitting any... to be used; and (g) For MVPDs subject to § 76.611, the cumulative signal leakage index derived...

  17. 40 CFR 265.302 - Action leakage rate.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 25 2010-07-01 2010-07-01 false Action leakage rate. 265.302 Section... FACILITIES Landfills § 265.302 Action leakage rate. (a) The owner or operator of landfill units subject to § 265.301(a) must submit a proposed action leakage rate to the Regional Administrator when...

  18. 40 CFR 265.222 - Action leakage rate.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 26 2014-07-01 2014-07-01 false Action leakage rate. 265.222 Section... FACILITIES Surface Impoundments § 265.222 Action leakage rate. (a) The owner or operator of surface impoundment units subject to § 265.221(a) must submit a proposed action leakage rate to the...

  19. 47 CFR 76.1803 - Signal leakage monitoring.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 47 Telecommunication 4 2011-10-01 2011-10-01 false Signal leakage monitoring. 76.1803 Section 76... MULTICHANNEL VIDEO AND CABLE TELEVISION SERVICE Reports and Filings § 76.1803 Signal leakage monitoring. MVPDs... of the method by which compliance with basic signal leakage criteria is achieved and the method...

  20. 42 CFR 84.92 - Exhalation valve leakage test.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 42 Public Health 1 2012-10-01 2012-10-01 false Exhalation valve leakage test. 84.92 Section 84.92... Breathing Apparatus § 84.92 Exhalation valve leakage test. (a) Dry exhalation valves and valve seats will be...) Leakage between the valve and the valve seat shall not exceed 30 milliliters per minute....

  1. 40 CFR 265.255 - Action leakage rates.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 27 2013-07-01 2013-07-01 false Action leakage rates. 265.255 Section... FACILITIES Waste Piles § 265.255 Action leakage rates. (a) The owner or operator of waste pile units subject to § 265.254 must submit a proposed action leakage rate to the Regional Administrator when...

  2. 42 CFR 84.92 - Exhalation valve leakage test.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 42 Public Health 1 2013-10-01 2013-10-01 false Exhalation valve leakage test. 84.92 Section 84.92... Breathing Apparatus § 84.92 Exhalation valve leakage test. (a) Dry exhalation valves and valve seats will be...) Leakage between the valve and the valve seat shall not exceed 30 milliliters per minute....

  3. 30 CFR 57.4102 - Spillage and leakage.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 30 Mineral Resources 1 2014-07-01 2014-07-01 false Spillage and leakage. 57.4102 Section 57.4102... Control Prohibitions/precautions/housekeeping § 57.4102 Spillage and leakage. Flammable or combustible liquid spillage or leakage shall be removed in a timely manner or controlled to prevent a fire hazard....

  4. 47 CFR 76.1803 - Signal leakage monitoring.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 47 Telecommunication 4 2010-10-01 2010-10-01 false Signal leakage monitoring. 76.1803 Section 76... MULTICHANNEL VIDEO AND CABLE TELEVISION SERVICE Reports and Filings § 76.1803 Signal leakage monitoring. MVPDs... of the method by which compliance with basic signal leakage criteria is achieved and the method...

  5. 47 CFR 76.1804 - Aeronautical frequencies: leakage monitoring (CLI).

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 47 Telecommunication 4 2014-10-01 2014-10-01 false Aeronautical frequencies: leakage monitoring... Aeronautical frequencies: leakage monitoring (CLI). An MVPD shall notify the Commission before transmitting any... to be used; and (g) For MVPDs subject to § 76.611, the cumulative signal leakage index derived...

  6. Simple leakage flow model for brush seals

    NASA Astrophysics Data System (ADS)

    Chupp, Raymond E.; Dowler, Constance A.; Holle, Glenn F.

    1991-06-01

    Brush seals are potential replacements for some or most of the air-to-air labyrinth seals in gas turbine engines. A simple flow model is presented to generalize brush seal leakage performance throughout the range of test and application environments. The model uses a single parameter, effective brush thickness, to correlate flow through the seal. This effective brush thickness is a measure of the compactness of the bristle bed. Initial model results have been obtained using leakage flow data from two investigators. The results indicate that this simple single parameter model gives insight into the active nature of a brush seal and approximately accounts for the effect of fluid temperature, especially at the higher pressure ratios, where brush seals are commonly applied.

  7. 3DHZETRN: Neutron leakage in finite objects

    NASA Astrophysics Data System (ADS)

    Wilson, John W.; Slaba, Tony C.; Badavi, Francis F.; Reddell, Brandon D.; Bahadori, Amir A.

    2015-11-01

    The 3DHZETRN formalism was recently developed as an extension to HZETRN with an emphasis on 3D corrections for neutrons and light ions. Comparisons to Monte Carlo (MC) simulations were used to verify the 3DHZETRN methodology in slab and spherical geometry, and it was shown that 3DHZETRN agrees with MC codes to the degree that various MC codes agree among themselves. One limitation of such comparisons is that all of the codes (3DHZETRN and three MC codes) utilize different nuclear models/databases; additionally, using a common nuclear model is impractical due to the complexity of the software. It is therefore difficult to ascertain if observed discrepancies are caused by transport code approximations or nuclear model differences. In particular, an important simplification in the 3DHZETRN formalism assumes that neutron production cross sections can be represented as the sum of forward and isotropic components, where the forward component is subsequently solved within the straight-ahead approximation. In the present report, previous transport model results in specific geometries are combined with additional results in related geometries to study neutron leakage using the Webber 1956 solar particle event as a source boundary condition. A ratio is defined to quantify the fractional neutron leakage at a point in a finite object relative to a semi-infinite slab geometry. Using the leakage ratio removes some of the dependence on the magnitude of the neutron production and clarifies the effects of angular scattering and absorption with regard to differences between the models. Discussion is given regarding observed differences between the MC codes and conclusions drawn about the need for further code development. Although the current version of 3DHZETRN is reasonably accurate compared to MC simulations, this study shows that improved leakage estimates can be obtained by replacing the isotropic/straight-ahead approximation with more detailed descriptions.

  8. Atomic Oxygen Effects on Seal Leakage

    NASA Technical Reports Server (NTRS)

    Christensen, John R.; Underwood, Steve D.; Kamenetzky, Rachel R.; Vaughn, Jason A.

    1999-01-01

    Common Berthing Mechanism (CBM provides the structural interface between separate International Space Station (ISS) elements, such as the Laboratory and Node modules. The CBM consists of an active and a passive half that join together with structural bolts. The seal at this interface is the CBM-to-CBM molded seal. The CBM-to-CBM interface is assembled on orbit, thus the seals can be exposed to the space environment for up to 65 hours. Atomic Oxygen/Vacuum Ultraviolet radiation (AO/VUV) in space is a potential hazard to the seals. Testing was conducted to determine the effect on leakage of the CBM-to-CBM seal material exposed to AO/VUV. The sealing materials were S383 silicone and V835 fluorocarbon material. Control samples, which were not exposed to the AO/VUV environment, were used to ensure that ff any changes in leakage occurred, they could be attributed to the AO/VUV exposure. After exposure to the AO/VUV environment the leakage increase was dramatic for the fluorocarbon. This testing was a major contributing factor in selecting silicone as the CBM-to-CBM seal material.

  9. Atomic Oxygen Effects on Seal Leakage

    NASA Technical Reports Server (NTRS)

    Christensen, John R.; Underwood, Steve D.; Kamenetzky, Rachel R.; Vaughn, Jason A.

    1998-01-01

    Common Berthing Mechanism (CBM) provides the structural interface between separate International Space Station (ISS) elements, such as the Laboratory and Node modules. The CBM consists of an active and a passive half that join together with structural bolts. The seal at this interface is the CBM-to-CBM molded seal. The CBM-to-CBM interface is assembled on orbit, thus the seals can be exposed to the space environment for up to 65 hours. Atomic Oxygen/Vacuum Ultraviolet radiation (AO/VUV) in space is a potential hazard to the seals. Testing was conducted to determine the effect on leakage of the CBM-to-CBM seal material exposed to AO/VUV. The sealing materials were S383 silicone and V835 fluorocarbon material. Control samples, which were not exposed to the AO/VUV environment, were used to ensure that if any changes in leakage occurred, they could be attributed to the AO/VUV exposure. After exposure to the AO/VUV environment the leakage increase was dramatic for the fluorocarbon. This testing was a major contributing factor in selecting silicone as the CBM-to-CBM seal material.

  10. Temporal patterns of nitrogen leakage from mid-Appalachian forested watersheds: Role of insect defoliation

    NASA Astrophysics Data System (ADS)

    Eshleman, Keith N.; Morgan, Raymond P.; Webb, James R.; Deviney, Frank A.; Galloway, James N.

    1998-08-01

    Fluxes of dissolved nitrogen (N) as nitrate from forested watersheds in the mid-Appalachian region have important water quality ramifications for small acid-sensitive streams and for downstream receiving waters such as the Chesapeake Bay. Previous studies of N leakage have suggested that annual dissolved N fluxes from small watersheds can vary by several orders of magnitude and may be increasing as second-growth forests gradually become N saturated from the accrual of atmospheric N loadings. In this study, we examined the temporal (intra-annual and interannual) variability in dissolved nitrate fluxes from five small (area < 15 km2) forested watersheds in the mid-Appalachian region from 1988 to 1995. At all sites, nitrate concentrations were observed to increase dramatically during storm flow events, with nitric acid contributing significantly to depressions in pH and acid-neutralizing capacity; annual nitrate fluxes were dominated by high-discharge periods. Interannually, the fluxes at each site varied by 1-2 orders of magnitude, but the patterns of N leakage displayed considerable synchrony with outbreaks of gypsy moth caterpillar defoliation that began in the late 1980s and early 1990s in this region. N leakage from forested watersheds apparently lagged the initial defoliation by several months to perhaps a year or more. Defoliation outbreaks by the gypsy moth caterpillar (or other herbivorous pests) thus provide an alternative explanation of N leakage from forest ecosystems. Poorly documented insect defoliations, rather than premature N saturation of intact forest ecosystems, need to be considered as a possible explanation of N leakage from forested watersheds in the mid-Appalachian region and elsewhere.

  11. FELERION: a new approach for leakage power reduction

    NASA Astrophysics Data System (ADS)

    R, Anjana; Somkuwar, Ajay

    2014-12-01

    The circuit proposed in this paper simultaneously reduces the sub threshold leakage power and saves the state of art aspect of the logic circuits. Sleep transistors and PMOS-only logic are used to further reduce the leakage power. Sleep transistors are used as the keepers to reduce the sub threshold leakage current providing the low resistance path to the output. PMOS-only logic is used between the pull up and pull down devices to mitigate the leakage power further. Our proposed fast efficient leakage reduction circuit not only reduces the leakage current but also reduces the power dissipation. Power and delay are analyzed at the 32 nm BSIM4 model for a chain of four inverters, NAND, NOR and ISCAS-85 c17 benchmark circuits using DSCH3 and the Microwind tool. The simulation results reveal that our proposed approach mitigates leakage power by 90%-94% as compared to the conventional approach.

  12. Reserves in Context: Planning for Leakage from Protected Areas

    PubMed Central

    Renwick, Anna R.; Bode, Michael; Venter, Oscar

    2015-01-01

    When protected areas reduce threats within their boundaries, they often displace a portion of these threats into adjacent areas through a process known as ‘leakage’, undermining conservation objectives. Using theoretical models and a case study of terrestrial mammals in Indonesia, we develop the first theoretical explanation of how leakage impacts conservation actions, and highlight conservation strategies that mitigate these impacts. Although leakage is a socio-economic process, we demonstrate that its negative impacts are also affected by the distribution of species, with leakage having larger impacts in landscapes with homogeneous distribution of species richness. Moreover, leakage has a greater negative effect when conservation strategies are implemented opportunistically, even creating the potential for perversely negative consequences from protected area establishment. Leakage thereby increases the relative benefits of systematic conservation planning over opportunism, especially in areas with high leakage and heterogeneously distributed species. Although leakage has the potential to undermine conservation actions, conservation planning can minimize this risk. PMID:26053163

  13. Simulation of permeability evolution of leakage pathway in carbonate-rich caprocks in carbon sequestration

    NASA Astrophysics Data System (ADS)

    Guo, B.; Fitts, J. P.; Dobossy, M. E.; Peters, C. A.

    2013-12-01

    the Michigan basin at an injection rate of 1 Mt/y. As an example, for a CVF value of 5%, the brine leakage rate after fifty years for a leakage pathway 1,000 m distance from the injection well is 0.88 kg/s, which is 2.4% larger than if there were no geochemical evolution of the permeability. In a sensitivity analysis with regard to the distance between the leakage pathway and the injection well, it was found that the cumulative leakage first increases with the distance and the relationship reverses after a certain distance. When the leakage pathway is farther away, the pressure increment drops leading to less acid brine flow; meanwhile, the time before the CO2 plume reaches the pathway is longer and this lengthens the reaction time with brine. Thirdly, we explored the role that SO2 would play if it were present as a co-injectant in carbon sequestration. The reaction considered is SO2 hydrolysis to form sulfurous acid. We expect the sulfurous acid will erode the calcite faster than carbonic acid because it is a stronger acid. Contrary to intuition, the simulation results showed a decrease in permeability due to CaSO3 precipitation in replacement of CaCO3, as CaSO3 has a larger molar volume.

  14. Radiation induced leakage current and stress induced leakage current in ultra-thin gate oxides

    SciTech Connect

    Ceschia, M.; Paccagnella, A. |; Cester, A.; Scarpa, A.; Ghidini, G.

    1998-12-01

    Low-field leakage current has been measured in thin oxides after exposure to ionizing radiation. This Radiation Induced Leakage Current (RILC) can be described as an inelastic tunneling process mediated by neutral traps in the oxide, with an energy loss of about 1 eV. The neutral trap distribution is influenced by the oxide field applied during irradiation, thus indicating that the precursors of the neutral defects are charged, likely being defects associated to trapped holes. The maximum leakage current is found under zero-field condition during irradiation, and it rapidly decreases as the field is enhanced, due to a displacement of the defect distribution across the oxide towards the cathodic interface. The RILC kinetics are linear with the cumulative dose, in contrast with the power law found on electrically stressed devices.

  15. EVA Suit Microbial Leakage Investigation Project

    NASA Technical Reports Server (NTRS)

    Falker, Jay; Baker, Christopher; Clayton, Ronald; Rucker, Michelle

    2016-01-01

    The objective of this project is to collect microbial samples from various EVA suits to determine how much microbial contamination is typically released during simulated planetary exploration activities. Data will be released to the planetary protection and science communities, and advanced EVA system designers. In the best case scenario, we will discover that very little microbial contamination leaks from our current or prototype suit designs, in the worst case scenario, we will identify leak paths, learn more about what affects leakage--and we'll have a new, flight-certified swab tool for our EVA toolbox.

  16. Counselor Hypothesis-Testing Strategies.

    ERIC Educational Resources Information Center

    Strohmer, Douglas C.; Newman, Lisa J.

    1983-01-01

    Reports two experiments relevant to the questioning strategies counselors use in testing their hypotheses about clients. Results supported the idea that counselors are able to take a tentative hypothesis about a client and test its accuracy against additional independent, unbiased observations of the client. (LLL)

  17. On the Weyl curvature hypothesis

    SciTech Connect

    Stoica, Ovidiu Cristinel

    2013-11-15

    The Weyl curvature hypothesis of Penrose attempts to explain the high homogeneity and isotropy, and the very low entropy of the early universe, by conjecturing the vanishing of the Weyl tensor at the Big-Bang singularity. In previous papers it has been proposed an equivalent form of Einstein’s equation, which extends it and remains valid at an important class of singularities (including in particular the Schwarzschild, FLRW, and isotropic singularities). Here it is shown that if the Big-Bang singularity is from this class, it also satisfies the Weyl curvature hypothesis. As an application, we study a very general example of cosmological models, which generalizes the FLRW model by dropping the isotropy and homogeneity constraints. This model also generalizes isotropic singularities, and a class of singularities occurring in Bianchi cosmologies. We show that the Big-Bang singularity of this model is of the type under consideration, and satisfies therefore the Weyl curvature hypothesis. -- Highlights: •The singularities we introduce are described by finite geometric/physical objects. •Our singularities have smooth Riemann and Weyl curvatures. •We show they satisfy Penrose’s Weyl curvature hypothesis (Weyl=0 at singularities). •Examples: FLRW, isotropic singularities, an extension of Schwarzschild’s metric. •Example: a large class of singularities which may be anisotropic and inhomogeneous.

  18. Argument as Hypothesis-Testing.

    ERIC Educational Resources Information Center

    Zarefsky, David

    The argumentative perspective enables rhetoric to function in a manner analagous to science or analytic philosophy, yielding reliable knowledge about nonempirical topics, which other methods cannot address. In short, argumentation is the equivalent of hypothesis-testing. Forensics should offer laboratory experience in developing this perspective…

  19. Paternal leakage of mitochondrial DNA in experimental crosses of populations of the potato cyst nematode Globodera pallida.

    PubMed

    Hoolahan, Angelique H; Blok, Vivian C; Gibson, Tracey; Dowton, Mark

    2011-12-01

    Animal mtDNA is typically assumed to be maternally inherited. Paternal mtDNA has been shown to be excluded from entering the egg or eliminated post-fertilization in several animals. However, in the contact zones of hybridizing species and populations, the reproductive barriers between hybridizing organisms may not be as efficient at preventing paternal mtDNA inheritance, resulting in paternal leakage. We assessed paternal mtDNA leakage in experimental crosses of populations of a cyst-forming nematode, Globodera pallida. A UK population, Lindley, was crossed with two South American populations, P5A and P4A. Hybridization of these populations was supported by evidence of nuclear DNA from both the maternal and paternal populations in the progeny. To assess paternal mtDNA leakage, a ~3.4 kb non-coding mtDNA region was analyzed in the parental populations and in the progeny. Paternal mtDNA was evident in the progeny of both crosses involving populations P5A and P4A. Further, paternal mtDNA replaced the maternal mtDNA in 22 and 40 % of the hybrid cysts from these crosses, respectively. These results indicate that under appropriate conditions, paternal leakage occurs in the mtDNA of parasitic nematodes, and supports the hypothesis that hybrid zones facilitate paternal leakage. Thus, assumptions of strictly maternal mtDNA inheritance may be frequently violated, particularly when divergent populations interbreed.

  20. Predicting Envelope Leakage in Attached Dwellings (Fact Sheet)

    SciTech Connect

    Not Available

    2013-11-01

    The most common method of measuring air leakage is to perform single (or solo) blower door pressurization and/or depressurization test. In detached housing, the single blower door test measures leakage to the outside. In attached housing, however, this "solo" test method measures both air leakage to the outside and air leakage between adjacent units through common surfaces. Although minimizing leakage to neighboring units is highly recommended to avoid indoor air quality issues between units, reduce pressure differentials between units, and control stack effect, the energy benefits of air sealing can be significantly overpredicted if the solo air leakage number is used in the energy analysis. Guarded blower door testing is more appropriate for isolating and measuring leakage to the outside in attached housing. This method uses multiple blower doors to depressurize adjacent spaces to the same level as the unit being tested. Maintaining a neutral pressure across common walls, ceilings, and floors acts as a "guard" against air leakage between units. The resulting measured air leakage in the test unit is only air leakage to the outside. Although preferred for assessing energy impacts, the challenges of performing guarded testing can be daunting.

  1. Geologic Carbon Sequestration: Leakage Potential and Policy Implications

    NASA Astrophysics Data System (ADS)

    Bielicki, J. M.; Peters, C. A.; Fitts, J. P.; Wilson, E. J.

    2014-12-01

    The geologic reservoirs that could be used for long-term sequestration of carbon dioxide (CO2) may have natural or manmade pathways that allow injected CO2, or the brine it displaces, to leak into overlying formations. Using a basin-scale leakage estimation model, we investigated the geophysical parameters that govern this leakage, and the resulting accumulations of leaked fluids in overlying formations. The results are discussed in the context of two polices aimed at governing long-term sequestration and protecting groundwater: the U.S. DOE guideline for storage permanence and the U.S. EPA UIC Program Class VI Rule. For a case study of CO2 injection into the Mt. Simon sandstone in the Michigan sedimentary basin, we showed that (1) the U.S. DOE guideline would allow for more leakage from larger injection projects than for smaller ones; (2) leakage amounts are determined mostly by well leakage permeability rather than by variation in formation permeabilities; (3) numerous leaking wells with anomalously high leakage permeabilities are necessary in order to achieve substantial leakage rates; (4) leakage can reach potable groundwater but intervening stratigraphic traps reduce the amount to be multiple orders of magnitude less than the leakage out of the reservoir, and (5) this leakage can reduce the Area of Review that is defined by the U.S. EPA as the area within which leakage can threaten groundwater. In summary, leakage that exceeds the U.S. DOE storage permanence goal would occur only under extreme conditions, the amount that reaches shallow potable groundwater may be inconsequential from a pollution standpoint, and leakage may be beneficial. Future federal policies should be harmonized to achieve the dual goals of protecting groundwater while allowing for adaptive management that incorporates uncertainties and imperfections inherent in geologic reservoirs.

  2. Gender and the hygiene hypothesis.

    PubMed

    Clough, Sharyn

    2011-02-01

    The hygiene hypothesis offers an explanation for the correlation, well-established in the industrialized nations of North and West, between increased hygiene and sanitation, and increased rates of asthma and allergies. Recent studies have added to the scope of the hypothesis, showing a link between decreased exposure to certain bacteria and parasitic worms, and increased rates of depression and intestinal auto-immune disorders, respectively. What remains less often discussed in the research on these links is that women have higher rates than men of asthma and allergies, as well as many auto-immune disorders, and also depression. The current paper introduces a feminist understanding of gender socialization to the epidemiological and immunological picture. That standards of cleanliness are generally higher for girls than boys, especially under the age of five when children are more likely to be under close adult supervision, is a robust phenomenon in industrialized nations, and some research points to a cross-cultural pattern. I conclude that, insofar as the hygiene hypothesis successfully identifies standards of hygiene and sanitation as mediators of immune health, then attention to the relevant patterns of gender socialization is important. The review also makes clear that adding a feminist analysis of gender socialization to the hygiene hypothesis helps explain variation in morbidity rates not addressed by other sources and responds to a number of outstanding puzzles in current research. Alternative explanations for the sex differences in the relevant morbidity rates are also discussed (e.g., the effects of estrogens). Finally, new sources of evidence for the hygiene hypothesis are suggested in the form of cross-cultural and other natural experiments. PMID:21195519

  3. EM information leakage from display unit and visual inspection for its leakage source

    NASA Astrophysics Data System (ADS)

    Watanabe, Takashi; Sako, Hiroshi

    2013-05-01

    Display unit emits a small amount of electromagnetic wave. Although it is weak enough to prevent interference with human body, information leaks through it. This paper presents an experiment on exploring the leakage source by visually inspecting the screen images reconstructed from captured electromagnetic waves. Additionally, some countermeasures are investigated to avoid the problem.

  4. Optical imaging to map blood-brain barrier leakage

    NASA Astrophysics Data System (ADS)

    Jaffer, Hayder; Adjei, Isaac M.; Labhasetwar, Vinod

    2013-11-01

    Vascular leakage in the brain is a major complication associated with brain injuries and certain pathological conditions due to disruption of the blood-brain barrier (BBB). We have developed an optical imaging method, based on excitation and emission spectra of Evans Blue dye, that is >1000-fold more sensitive than conventional ultraviolet spectrophotometry. We used a rat thromboembolic stroke model to validate the usefulness of our method for vascular leakage. Optical imaging data show that vascular leakage varies in different areas of the post-stroke brain and that administering tissue plasminogen activator causes further leakage. The new method is quantitative, simple to use, requires no tissue processing, and can map the degree of vascular leakage in different brain locations. The high sensitivity of our method could potentially provide new opportunities to study BBB leakage in different pathological conditions and to test the efficacy of various therapeutic strategies to protect the BBB.

  5. Residential Forced Air System Cabinet Leakage and Blower Performance

    SciTech Connect

    Walker, Iain S.; Dickerhoff, Darryl J.; Delp, William W.

    2010-03-01

    This project evaluated the air leakage and electric power consumption of Residential HVAC components, with a particular focus on air leakage of furnace cabinets. Laboratory testing of HVAC components indicated that air leakage can be significant and highly variable from unit to unit ? indicating the need for a standard test method and specifying maximum allowable air leakage in California State energy codes. To further this effort, this project provided technical assistance for the development of a national standard for Residential HVAC equipment air leakage. This standard is being developed by ASHRAE and is called"ASHRAE Standard 193P - Method of test for Determining the Air Leakage Rate of HVAC Equipment". The final part of this project evaluated techniques for measurement of furnace blower power consumption. A draft test procedure for power consumption was developed in collaboration with the Canadian General Standards Board: CSA 823"Performance Standard for air handlers in residential space conditioning systems".

  6. Ecological Hypothesis of Dentin and Root Caries.

    PubMed

    Takahashi, Nobuhiro; Nyvad, Bente

    2016-01-01

    Recent advances regarding the caries process indicate that ecological phenomena induced by bacterial acid production tilt the de- and remineralization balance of the dental hard tissues towards demineralization through bacterial acid-induced adaptation and selection within the microbiota - from the dynamic stability stage to the aciduric stage via the acidogenic stage [Takahashi and Nyvad, 2008]. Dentin and root caries can also be partly explained by this hypothesis; however, the fact that these tissues contain a considerable amount of organic material suggests that protein degradation is involved in caries formation. In this review, we compiled relevant histological, biochemical, and microbiological information about dentin/root caries and refined the hypothesis by adding degradation of the organic matrix (the proteolytic stage) to the abovementioned stages. Bacterial acidification not only induces demineralization and exposure of the organic matrix in dentin/root surfaces but also activation of dentin-embedded and salivary matrix metalloproteinases and cathepsins. These phenomena initiate degradation of the demineralized organic matrix in dentin/root surfaces. While a bacterial involvement has never been confirmed in the initial degradation of organic material, the detection of proteolytic/amino acid-degrading bacteria and bacterial metabolites in dentin and root caries suggests a bacterial digestion and metabolism of partly degraded matrix. Moreover, bacterial metabolites might induce pulpitis as an inflammatory/immunomodulatory factor. Root and dentin surfaces are always at risk of becoming demineralized in the oral cavity, and exposed organic materials can be degraded by host-derived proteases contained in saliva and dentin itself. New approaches to the prevention and treatment of root/dentin caries are required. PMID:27458979

  7. Metabolic hypothesis for human altriciality

    PubMed Central

    Dunsworth, Holly M.; Warrener, Anna G.; Deacon, Terrence; Ellison, Peter T.; Pontzer, Herman

    2012-01-01

    The classic anthropological hypothesis known as the “obstetrical dilemma” is a well-known explanation for human altriciality, a condition that has significant implications for human social and behavioral evolution. The hypothesis holds that antagonistic selection for a large neonatal brain and a narrow, bipedal-adapted birth canal poses a problem for childbirth; the hominin “solution” is to truncate gestation, resulting in an altricial neonate. This explanation for human altriciality based on pelvic constraints persists despite data linking human life history to that of other species. Here, we present evidence that challenges the importance of pelvic morphology and mechanics in the evolution of human gestation and altriciality. Instead, our analyses suggest that limits to maternal metabolism are the primary constraints on human gestation length and fetal growth. Although pelvic remodeling and encephalization during hominin evolution contributed to the present parturitional difficulty, there is little evidence that pelvic constraints have altered the timing of birth. PMID:22932870

  8. Postoperative Cerebrospinal Fluid Leakage Associated With Total En Bloc Spondylectomy.

    PubMed

    Yokogawa, Noriaki; Murakami, Hideki; Demura, Satoru; Kato, Satoshi; Yoshioka, Katsuhito; Hayashi, Hiroyuki; Ishii, Takayoshi; Igarashi, Takashi; Fang, Xiang; Tsuchiya, Hiroyuki

    2015-07-01

    Cerebrospinal fluid (CSF) leakage is a serious postoperative complication associated with total en bloc spondylectomy. The authors examined the risk factors for CSF leakage after this procedure. A total of 72 patients underwent total en bloc spondylectomy at the authors' institution between May 2010 and April 2013. Postoperative CSF leakage was observed in 17 of the 72 patients (23.6%). The results of univariate analysis suggested that age 54 years or older, preoperative surgical site irradiation, resection of 3 or more vertebral bodies, and dural injury were significant risk factors for postoperative CSF leakage after total en bloc spondylectomy. Multivariate analysis showed that preoperative surgical site irradiation was the only significant risk factor for postoperative CSF leakage (adjusted odds ratio, 5.22; 95% confidence interval, 1.03-26.45, P=.046). The authors also assessed the course of treatment for postoperative CSF leakage in each patient. Of 17 patients with postoperative CSF leakage, 13 recovered without further complications, but 4 required reoperation (2 for wound dehiscence, 1 for surgical site infection, and 1 for severe intracranial hypotension). All 4 patients who required reoperation had a history of surgical site irradiation. Thus, this study suggests that careful consideration should be given to postoperative CSF leakage in patients with a history of surgical site irradiation. These findings may contribute to the management of postoperative CSF leakage associated with total en bloc spondylectomy and supplement the information given to the patient in the process of obtaining informed consent.

  9. Information Leakage Analysis by Abstract Interpretation

    NASA Astrophysics Data System (ADS)

    Zanioli, Matteo; Cortesi, Agostino

    Protecting the confidentiality of information stored in a computer system or transmitted over a public network is a relevant problem in computer security. The approach of information flow analysis involves performing a static analysis of the program with the aim of proving that there will not be leaks of sensitive information. In this paper we propose a new domain that combines variable dependency analysis, based on propositional formulas, and variables' value analysis, based on polyhedra. The resulting analysis is strictly more accurate than the state of the art abstract interpretation based analyses for information leakage detection. Its modular construction allows to deal with the tradeoff between efficiency and accuracy by tuning the granularity of the abstraction and the complexity of the abstract operators.

  10. Fluid leakage near the percolation threshold

    NASA Astrophysics Data System (ADS)

    Dapp, Wolf B.; Müser, Martin H.

    2016-02-01

    Percolation is a concept widely used in many fields of research and refers to the propagation of substances through porous media (e.g., coffee filtering), or the behaviour of complex networks (e.g., spreading of diseases). Percolation theory asserts that most percolative processes are universal, that is, the emergent powerlaws only depend on the general, statistical features of the macroscopic system, but not on specific details of the random realisation. In contrast, our computer simulations of the leakage through a seal—applying common assumptions of elasticity, contact mechanics, and fluid dynamics—show that the critical behaviour (how the flow ceases near the sealing point) solely depends on the microscopic details of the last constriction. It appears fundamentally impossible to accurately predict from statistical properties of the surfaces alone how strongly we have to tighten a water tap to make it stop dripping and also how it starts dripping once we loosen it again.

  11. Fluid leakage near the percolation threshold.

    PubMed

    Dapp, Wolf B; Müser, Martin H

    2016-01-01

    Percolation is a concept widely used in many fields of research and refers to the propagation of substances through porous media (e.g., coffee filtering), or the behaviour of complex networks (e.g., spreading of diseases). Percolation theory asserts that most percolative processes are universal, that is, the emergent powerlaws only depend on the general, statistical features of the macroscopic system, but not on specific details of the random realisation. In contrast, our computer simulations of the leakage through a seal--applying common assumptions of elasticity, contact mechanics, and fluid dynamics--show that the critical behaviour (how the flow ceases near the sealing point) solely depends on the microscopic details of the last constriction. It appears fundamentally impossible to accurately predict from statistical properties of the surfaces alone how strongly we have to tighten a water tap to make it stop dripping and also how it starts dripping once we loosen it again. PMID:26839261

  12. Torque Transmission Device at Zero Leakage

    NASA Technical Reports Server (NTRS)

    Hendricks, R. C.; Mullen, R. L.

    2005-01-01

    In a few critical applications, mechanical transmission of power by rotation at low speed is required without leakage at an interface. Herein we examine a device that enables torque to be transmitted across a sealed environmental barrier. The barrier represents the restraint membrane through which the torque is transmitted. The power is transferred through elastic deformation of a circular tube into an elliptical cross-section. Rotation of the principle axis of the ellipse at one end results in a commensurate rotation of an elliptical cross section at the other end of the tube. This transfer requires no rigid body rotation of the tube allowing a membrane to seal one end from the other. Both computational and experimental models of the device are presented.

  13. Fluid leakage near the percolation threshold

    PubMed Central

    Dapp, Wolf B.; Müser, Martin H.

    2016-01-01

    Percolation is a concept widely used in many fields of research and refers to the propagation of substances through porous media (e.g., coffee filtering), or the behaviour of complex networks (e.g., spreading of diseases). Percolation theory asserts that most percolative processes are universal, that is, the emergent powerlaws only depend on the general, statistical features of the macroscopic system, but not on specific details of the random realisation. In contrast, our computer simulations of the leakage through a seal—applying common assumptions of elasticity, contact mechanics, and fluid dynamics—show that the critical behaviour (how the flow ceases near the sealing point) solely depends on the microscopic details of the last constriction. It appears fundamentally impossible to accurately predict from statistical properties of the surfaces alone how strongly we have to tighten a water tap to make it stop dripping and also how it starts dripping once we loosen it again. PMID:26839261

  14. Beyond the Black Queen Hypothesis.

    PubMed

    Mas, Alix; Jamshidi, Shahrad; Lagadeuc, Yvan; Eveillard, Damien; Vandenkoornhuyse, Philippe

    2016-09-01

    The Black Queen Hypothesis, recently proposed to explain an evolution of dependency based on gene loss, is gaining ground. This paper focuses on how the evolution of dependency transforms interactions and the community. Using agent-based modeling we suggest that species specializing in the consumption of a common good escape competition and therefore favor coexistence. This evolutionary trajectory could open the way for novel long-lasting interactions and a need to revisit the classically accepted assembly rules. Such evolutionary events also reshape the structure and dynamics of communities, depending on the spatial heterogeneity of the common good production. Let Black be the new black! PMID:26953598

  15. A Molecular–Structure Hypothesis

    PubMed Central

    Boeyens, Jan C. A.

    2010-01-01

    The self-similar symmetry that occurs between atomic nuclei, biological growth structures, the solar system, globular clusters and spiral galaxies suggests that a similar pattern should characterize atomic and molecular structures. This possibility is explored in terms of the current molecular structure-hypothesis and its extension into four-dimensional space-time. It is concluded that a quantum molecule only has structure in four dimensions and that classical (Newtonian) structure, which occurs in three dimensions, cannot be simulated by quantum-chemical computation. PMID:21151437

  16. Antiaging therapy: a prospective hypothesis.

    PubMed

    Shahidi Bonjar, Mohammad Rashid; Shahidi Bonjar, Leyla

    2015-01-01

    This hypothesis proposes a new prospective approach to slow the aging process in older humans. The hypothesis could lead to developing new treatments for age-related illnesses and help humans to live longer. This hypothesis has no previous documentation in scientific media and has no protocol. Scientists have presented evidence that systemic aging is influenced by peculiar molecules in the blood. Researchers at Albert Einstein College of Medicine, New York, and Harvard University in Cambridge discovered elevated titer of aging-related molecules (ARMs) in blood, which trigger cascade of aging process in mice; they also indicated that the process can be reduced or even reversed. By inhibiting the production of ARMs, they could reduce age-related cognitive and physical declines. The present hypothesis offers a new approach to translate these findings into medical treatment: extracorporeal adjustment of ARMs would lead to slower rates of aging. A prospective "antiaging blood filtration column" (AABFC) is a nanotechnological device that would fulfill the central role in this approach. An AABFC would set a near-youth homeostatic titer of ARMs in the blood. In this regard, the AABFC immobilizes ARMs from the blood while blood passes through the column. The AABFC harbors antibodies against ARMs. ARM antibodies would be conjugated irreversibly to ARMs on contact surfaces of the reaction platforms inside the AABFC till near-youth homeostasis is attained. The treatment is performed with the aid of a blood-circulating pump. Similar to a renal dialysis machine, blood would circulate from the body to the AABFC and from there back to the body in a closed circuit until ARMs were sufficiently depleted from the blood. The optimal application criteria, such as human age for implementation, frequency of treatments, dosage, ideal homeostasis, and similar concerns, should be revealed by appropriate investigations. If AABFC technology undergoes practical evaluations and gains approval

  17. In search of the hypothesis.

    PubMed Central

    Kaufman, J S; Cooper, R S

    1995-01-01

    Epidemiologic studies of racial differences sorely lack sound and explicit hypotheses. Race is a social convention, not a biological concept. Its careless use in epidemiology demonstrates a failure to generate appropriate hypotheses to study its role in health. Studies of hypertension in blacks illustrate the point. Two underlying pitfalls plague hypothesis generation: directionality involving the null and alternative hypotheses and circularity, where efforts to understand social factors have the effect of emphasizing racial differences. The proper prescription is to identify explicitly the hypotheses of interest, including their origins and implication. Images p662-a p665-a PMID:8570813

  18. A quantitative methodology to assess the risks to human health from CO 2 leakage into groundwater

    NASA Astrophysics Data System (ADS)

    Siirila, Erica R.; Navarre-Sitchler, Alexis K.; Maxwell, Reed M.; McCray, John E.

    2012-02-01

    Leakage of CO 2 and associated gases into overlying aquifers as a result of geologic carbon capture and sequestration may have adverse impacts on aquifer drinking-water quality. Gas or aqueous-phase leakage may occur due to transport via faults and fractures, through faulty well bores, or through leaky confining materials. Contaminants of concern include aqueous salts and dissolved solids, gaseous or aqueous-phase organic contaminants, and acidic gas or aqueous-phase fluids that can liberate metals from aquifer minerals. Here we present a quantitative risk assessment framework to predict potential human health risk from CO 2 leakage into drinking water aquifers. This framework incorporates the potential release of CO 2 into the drinking water aquifer; mobilization of metals due to a decrease in pH; transport of these metals down gradient to municipal receptors; distributions of contaminated groundwater to multiple households; and exposure and health risk to individuals using this water for household purposes. Additionally, this framework is stochastic, incorporates detailed variations in geological and geostatistical parameters and discriminates between uncertain and variable parameters using a two-stage, or nested, Monte Carlo approach. This approach is demonstrated using example simulations with hypothetical, yet realistic, aquifer characteristics and leakage scenarios. These example simulations show a greater risk for arsenic than for lead for both cancer and non-cancer endpoints, an unexpected finding. Higher background groundwater gradients also yield higher risk. The overall risk and the associated uncertainty are sensitive to the extent of aquifer stratification and the degree of local-scale dispersion. These results all highlight the importance of hydrologic modeling in risk assessment. A linear relationship between carcinogenic and noncarcinogenic risk was found for arsenic and suggests action levels for carcinogenic risk will be exceeded in exposure

  19. 49 CFR 178.348-5 - Pressure and leakage test.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 3 2011-10-01 2011-10-01 false Pressure and leakage test. 178.348-5 Section 178... Specifications for Containers for Motor Vehicle Transportation § 178.348-5 Pressure and leakage test. (a) Each cargo tank must be tested in accordance with § 178.345-13 and this section. (b) Pressure test....

  20. 49 CFR 178.346-5 - Pressure and leakage tests.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... is equipped with vapor recovery equipment may be leakage tested in accordance with 40 CFR 63.425(e). To satisfy the leakage test requirements of this paragraph, the test specified in 40 CFR 63.425(e)(1) must be conducted using air. The hydrostatic test alternative permitted under Appendix A to 40 CFR...

  1. 49 CFR 178.348-5 - Pressure and leakage test.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 2 2010-10-01 2010-10-01 false Pressure and leakage test. 178.348-5 Section 178... PACKAGINGS Specifications for Containers for Motor Vehicle Transportation § 178.348-5 Pressure and leakage test. (a) Each cargo tank must be tested in accordance with § 178.345-13 and this section. (b)...

  2. 49 CFR 178.347-5 - Pressure and leakage test.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 49 Transportation 3 2013-10-01 2013-10-01 false Pressure and leakage test. 178.347-5 Section 178... Specifications for Containers for Motor Vehicle Transportation § 178.347-5 Pressure and leakage test. (a) Each cargo tank must be tested in accordance with § 178.345-13 and this section. (b) Pressure test....

  3. 49 CFR 178.346-5 - Pressure and leakage tests.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... is equipped with vapor recovery equipment may be leakage tested in accordance with 40 CFR 63.425(e). To satisfy the leakage test requirements of this paragraph, the test specified in 40 CFR 63.425(e)(1) must be conducted using air. The hydrostatic test alternative permitted under Appendix A to 40 CFR...

  4. 49 CFR 178.347-5 - Pressure and leakage test.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 2 2010-10-01 2010-10-01 false Pressure and leakage test. 178.347-5 Section 178... PACKAGINGS Specifications for Containers for Motor Vehicle Transportation § 178.347-5 Pressure and leakage test. (a) Each cargo tank must be tested in accordance with § 178.345-13 and this section. (b)...

  5. 49 CFR 178.348-5 - Pressure and leakage test.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 49 Transportation 3 2014-10-01 2014-10-01 false Pressure and leakage test. 178.348-5 Section 178... Specifications for Containers for Motor Vehicle Transportation § 178.348-5 Pressure and leakage test. (a) Each cargo tank must be tested in accordance with § 178.345-13 and this section. (b) Pressure test....

  6. 49 CFR 178.348-5 - Pressure and leakage test.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 49 Transportation 3 2012-10-01 2012-10-01 false Pressure and leakage test. 178.348-5 Section 178... Specifications for Containers for Motor Vehicle Transportation § 178.348-5 Pressure and leakage test. (a) Each cargo tank must be tested in accordance with § 178.345-13 and this section. (b) Pressure test....

  7. 49 CFR 178.346-5 - Pressure and leakage tests.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... is equipped with vapor recovery equipment may be leakage tested in accordance with 40 CFR 63.425(e). To satisfy the leakage test requirements of this paragraph, the test specified in 40 CFR 63.425(e)(1) must be conducted using air. The hydrostatic test alternative permitted under Appendix A to 40 CFR...

  8. 49 CFR 178.347-5 - Pressure and leakage test.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 3 2011-10-01 2011-10-01 false Pressure and leakage test. 178.347-5 Section 178... Specifications for Containers for Motor Vehicle Transportation § 178.347-5 Pressure and leakage test. (a) Each cargo tank must be tested in accordance with § 178.345-13 and this section. (b) Pressure test....

  9. 49 CFR 178.347-5 - Pressure and leakage test.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 49 Transportation 3 2014-10-01 2014-10-01 false Pressure and leakage test. 178.347-5 Section 178... Specifications for Containers for Motor Vehicle Transportation § 178.347-5 Pressure and leakage test. (a) Each cargo tank must be tested in accordance with § 178.345-13 and this section. (b) Pressure test....

  10. 49 CFR 178.347-5 - Pressure and leakage test.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 49 Transportation 3 2012-10-01 2012-10-01 false Pressure and leakage test. 178.347-5 Section 178... Specifications for Containers for Motor Vehicle Transportation § 178.347-5 Pressure and leakage test. (a) Each cargo tank must be tested in accordance with § 178.345-13 and this section. (b) Pressure test....

  11. 49 CFR 178.348-5 - Pressure and leakage test.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 49 Transportation 3 2013-10-01 2013-10-01 false Pressure and leakage test. 178.348-5 Section 178... Specifications for Containers for Motor Vehicle Transportation § 178.348-5 Pressure and leakage test. (a) Each cargo tank must be tested in accordance with § 178.345-13 and this section. (b) Pressure test....

  12. 49 CFR 178.346-5 - Pressure and leakage tests.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... is equipped with vapor recovery equipment may be leakage tested in accordance with 40 CFR 63.425(e). To satisfy the leakage test requirements of this paragraph, the test specified in 40 CFR 63.425(e)(1) must be conducted using air. The hydrostatic test alternative permitted under Appendix A to 40 CFR...

  13. 40 CFR 89.316 - Analyzer leakage and response time.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... Equipment Provisions § 89.316 Analyzer leakage and response time. (a) Vacuum side leak check. (1) Any location within the analysis system where a vacuum leak could affect the test results must be checked. (2) The maximum allowable leakage rate on the vacuum side is 0.5 percent of the in-use flow rate for...

  14. 40 CFR 90.324 - Analyzer leakage check.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... Provisions § 90.324 Analyzer leakage check. (a) Vacuum side leak check. (1) Check any location within the analysis system where a vacuum leak could affect the test results. (2) The maximum allowable leakage rate on the vacuum side is 0.5 percent of the in-use flow rate for the portion of the system being...

  15. 40 CFR 89.316 - Analyzer leakage and response time.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... Equipment Provisions § 89.316 Analyzer leakage and response time. (a) Vacuum side leak check. (1) Any location within the analysis system where a vacuum leak could affect the test results must be checked. (2) The maximum allowable leakage rate on the vacuum side is 0.5 percent of the in-use flow rate for...

  16. 40 CFR 90.324 - Analyzer leakage check.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... Provisions § 90.324 Analyzer leakage check. (a) Vacuum side leak check. (1) Check any location within the analysis system where a vacuum leak could affect the test results. (2) The maximum allowable leakage rate on the vacuum side is 0.5 percent of the in-use flow rate for the portion of the system being...

  17. 40 CFR 89.316 - Analyzer leakage and response time.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... Equipment Provisions § 89.316 Analyzer leakage and response time. (a) Vacuum side leak check. (1) Any location within the analysis system where a vacuum leak could affect the test results must be checked. (2) The maximum allowable leakage rate on the vacuum side is 0.5 percent of the in-use flow rate for...

  18. 40 CFR 89.316 - Analyzer leakage and response time.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... Equipment Provisions § 89.316 Analyzer leakage and response time. (a) Vacuum side leak check. (1) Any location within the analysis system where a vacuum leak could affect the test results must be checked. (2) The maximum allowable leakage rate on the vacuum side is 0.5 percent of the in-use flow rate for...

  19. 40 CFR 90.324 - Analyzer leakage check.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... Provisions § 90.324 Analyzer leakage check. (a) Vacuum side leak check. (1) Check any location within the analysis system where a vacuum leak could affect the test results. (2) The maximum allowable leakage rate on the vacuum side is 0.5 percent of the in-use flow rate for the portion of the system being...

  20. 40 CFR 89.316 - Analyzer leakage and response time.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... Equipment Provisions § 89.316 Analyzer leakage and response time. (a) Vacuum side leak check. (1) Any location within the analysis system where a vacuum leak could affect the test results must be checked. (2) The maximum allowable leakage rate on the vacuum side is 0.5 percent of the in-use flow rate for...

  1. 40 CFR 90.324 - Analyzer leakage check.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... Provisions § 90.324 Analyzer leakage check. (a) Vacuum side leak check. (1) Check any location within the analysis system where a vacuum leak could affect the test results. (2) The maximum allowable leakage rate on the vacuum side is 0.5 percent of the in-use flow rate for the portion of the system being...

  2. 40 CFR 90.324 - Analyzer leakage check.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... Provisions § 90.324 Analyzer leakage check. (a) Vacuum side leak check. (1) Check any location within the analysis system where a vacuum leak could affect the test results. (2) The maximum allowable leakage rate on the vacuum side is 0.5 percent of the in-use flow rate for the portion of the system being...

  3. Improved Steam Turbine Leakage Control with a Brush Seal Design

    NASA Astrophysics Data System (ADS)

    Turnquist, Norman; Chupp, Raymond E.; Pastrana, Ryan; Wolfe, Chris; Burnett, Mark

    2002-10-01

    This paper presents an improved steam turbine leakage control system with a brush seal design. The contents include: 1) Typical Design Characteristics; 2) Typical Brush Seal Locations; 3) Reduced Leakage Rates; 4) Performance Benefits; 5) System Considerations; 6) Rotor Dynamics; 7) Laboratory Tests and 8) Field Experience.

  4. 42 CFR 84.158 - Exhalation valve leakage test.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 42 Public Health 1 2010-10-01 2010-10-01 false Exhalation valve leakage test. 84.158 Section 84... Respirators § 84.158 Exhalation valve leakage test. (a) Dry exhalation valves and valve seats will be... between the valve and valve seat shall not exceed 30 milliliters per minute....

  5. 42 CFR 84.158 - Exhalation valve leakage test.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 42 Public Health 1 2011-10-01 2011-10-01 false Exhalation valve leakage test. 84.158 Section 84... Respirators § 84.158 Exhalation valve leakage test. (a) Dry exhalation valves and valve seats will be... between the valve and valve seat shall not exceed 30 milliliters per minute....

  6. A CONCEPTUAL UNDERSTANDING OF LEAKAGE DURING SOIL-GAS SAMPLING

    EPA Science Inventory

    A heuristic model is developed to develop a conceptual understanding of leakage during soil-gas sampling. Leakage is shown to be simply a function of the permeability contrast between the formation and borehole and geometric factors. As the ratio of formation to borehole permea...

  7. 42 CFR 84.158 - Exhalation valve leakage test.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 42 Public Health 1 2013-10-01 2013-10-01 false Exhalation valve leakage test. 84.158 Section 84... Respirators § 84.158 Exhalation valve leakage test. (a) Dry exhalation valves and valve seats will be subjected to a suction of 25 mm. water-column height while in a normal operating position. (b)...

  8. 42 CFR 84.158 - Exhalation valve leakage test.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 42 Public Health 1 2014-10-01 2014-10-01 false Exhalation valve leakage test. 84.158 Section 84... Respirators § 84.158 Exhalation valve leakage test. (a) Dry exhalation valves and valve seats will be subjected to a suction of 25 mm. water-column height while in a normal operating position. (b)...

  9. 42 CFR 84.158 - Exhalation valve leakage test.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 42 Public Health 1 2012-10-01 2012-10-01 false Exhalation valve leakage test. 84.158 Section 84... Respirators § 84.158 Exhalation valve leakage test. (a) Dry exhalation valves and valve seats will be subjected to a suction of 25 mm. water-column height while in a normal operating position. (b)...

  10. North Pacific High: an hypothesis

    NASA Astrophysics Data System (ADS)

    Kenyon, Kern E.

    An hypothesis is offered for the cause and maintenance of the North Pacific High (NPH). Over a broad but well defined open ocean area, in the mid-latitude North Pacific, the ocean heats the atmosphere from below, and outside the boundaries of the heat source the ocean cools the air at the sea surface. Vertical thermal convection in the air over the heat source brings down relatively cool dry air, producing a horizontal contrast mainly in relative humidity inside and outside the heat source region. Consequently relatively high density air is produced over the heat source, and if the temperature is approximately constant, then the barometric pressure will be high over the heat source as well. Being unstable, due to a horizontal pressure gradient, the high density air will try to move radially outward from the heat source, and the Coriolis force will bend the outward flow into a clockwise circulation around the center of high pressure. The heat source is provided by a broad northeastward warm surface current, previously described, that crosses mid-latitudes on the eastern side of the North Pacific at all times of the year. Given the known characteristics of the warm current, the heat source mechanism can explain the observed seasonal variations of the NPH also. A more complete substantiation (or refutation) of the general hypothesis for the origin of the NPH must await the accumulation of additional oceanic and atmospheric data.

  11. Technology Solutions Case Study: Predicting Envelope Leakage in Attached Dwellings

    SciTech Connect

    2013-11-01

    The most common method of measuring air leakage is to perform single (or solo) blower door pressurization and/or depressurization test. In detached housing, the single blower door test measures leakage to the outside. In attached housing, however, this “solo” test method measures both air leakage to the outside and air leakage between adjacent units through common surfaces. In an attempt to create a simplified tool for predicting leakage to the outside, Building America team Consortium for Advanced Residential Buildings (CARB) performed a preliminary statistical analysis on blower door test results from 112 attached dwelling units in four apartment complexes. Although the subject data set is limited in size and variety, the preliminary analyses suggest significant predictors are present and support the development of a predictive model. Further data collection is underway to create a more robust prediction tool for use across different construction types, climate zones, and unit configurations.

  12. Endoscopic Treatment of Stump Leakage Related to the Ileal Conduit

    PubMed Central

    Odemis, Bulent; Oztas, Erkin; Akpinar, Muhammet Yener; Olcucuoglu, Erkan; Kayacetin, Ertugrul

    2016-01-01

    Abstract Background: Ileal conduit with leakage from either the anastomotic site or the stump is associated with high morbidity and mortality rates. The standard treatment of stump leakage is surgery. Case Presentation: A 60-year-old male patient was admitted to our hospital with complaint of hematuria and bladder carcinoma was diagnosed. After performing radical cystectomy and ileal conduit, he developed fever with abdominal pain within the first week of surgery. Stump leakage was diagnosed by endoscopic examination performed through a gastroscope. After two over-the-scope clips (OTSCs) were applied to the stump, vinyl mesh was inserted into the space between the OTSCs. Later, cyanoacrylat and lipiodol were repelled on the OTSCs and vinyl mesh. Subsequently, stump leakage was resolved. Conclusion: This is the first case of stump leakage related to ileal conduit that has been treated endoscopically, according to the current literature. PMID:27579432

  13. Capillary leakage in travelers with dengue infection: implications for pathogenesis.

    PubMed

    Meltzer, Eyal; Heyman, Zahava; Bin, Hanna; Schwartz, Eli

    2012-03-01

    Dengue hemorrhagic fever is characterized by the presence of a capillary leak syndrome. Its pathogenesis is presumed to differ from that of classical dengue fever (DF) and to be associated with secondary dengue infection. Returning travelers given a diagnosis of DF were evaluated for capillary leakage with abdominal sonography. Data were compared between travelers with primary/secondary infection defined by epidemiologic and serologic parameters. A total of 12 (34.3%) of 35 patients had sonographic signs of capillary leakage. Most (85%) patients with capillary leakage had classical DF. Capillary leak was diagnosed in 32% of primary dengue cases and in 40% of secondary dengue cases (P = 0.69). The two patients given a diagnosis of dengue hemorrhagic fever had primary infections. The high prevalence of capillary leakage among travelers, most of them with primary exposure to dengue, calls into question the importance of secondary infection in causing capillary leakage in dengue infection.

  14. Suppressing leakage by localized doping in Si nanotransistor channels.

    PubMed

    Maassen, Jesse; Guo, Hong

    2012-12-28

    By first principles atomistic analysis we demonstrate how controlled localized doping distributions in nanoscale Si transistors can suppress leakage currents. We consider dopants (B and P atoms) to be randomly confined to a ≈1  nm width doping region in the channel. If this region is located away from the electrodes, roughly 20% of the channel length L, the tunneling leakage is reduced 2× compared to the case of uniform doping and shows little variation. Oppositely, we find the leakage current increases by orders of magnitude and may result in large device variability. We calculate the maximum and minimum conductance ratio that characterizes the tunnel leakage for various values of L. We conclude that doping engineering provides a possible approach to resolve the critical issue of leakage current in nanotransistors. PMID:23368599

  15. Study on Acoustic Catheter of Boiler Tube Leakage Monitoring Systems

    NASA Astrophysics Data System (ADS)

    Lv, Yongxing; Feng, Qiang

    Boiler tube leakage is the major reason of affecting the safe operation of the unit now, there are 3 methods of the "four tube" leakage detection: Traditional method, filtering method and acoustic spectrum analysis, acoustic spectrum analysis is the common method, but this method have low sensitivity and the sensor damage easily. Therewith, designed the special acoustic catheter with acoustic resonance cavity type, proved by experiments, the acoustic catheter with acoustic resonance cavity type can enhance leakage sound, can accurately extract leakage signals, has high sensitivity, and can avoid the effect of sensor by fire and hot-gas when the furnace is in positive pressure situation, reduce the installation and maintenance costs of the boiler tube leakage monitor system.

  16. Effects of protein leakage on online monitoring of ultraviolet absorbance in spent dialysate.

    PubMed

    Yamamoto, Ken-Ichiro; Hirakawa, Shinya; Murakami, Jun; Akiba, Takashi; Mineshima, Michio

    2016-09-01

    Recently, dialysis dose during hemodialysis treatment has been monitored by measuring the concentration of urea-like solutes such as uric acid in spent dialysate using near-ultraviolet (UV) light. The measured absorbance has been shown to have a good correlation with the time course of urea level even if the absorbance does not result from urea. However, the spent dialysate includes various solutes such as uric acid and albumin as well as unknown solutes that also absorb UV light. The effects of these solutes on monitored absorbance values are not clear. In this study, we evaluated the effect of protein leakage on data from the UV monitoring of spent dialysate. Albumin leakage in the earlier stage of the treatment may result in an increase in absorbance greater than the expected value. As a result, there is a possibility that the dialysis dose is overestimated. On the other hand, the quantity of albumin leakage could be estimated by a spent dialysate monitoring technique combined with a protein removal process.

  17. Ecology: Darwin's naturalization hypothesis challenged.

    PubMed

    Duncan, Richard P; Williams, Peter A

    2002-06-01

    Naturalized plants can have a significant ecological and economic impact, yet they comprise only a fraction ot the plant species introduced by humans. Darwin proposed that introduced plant species will be less likely to establish a self-sustaining wild population in places with congeneric native species because the introduced plants have to compete with their close relatives, or are more likely to be attacked by native herbivores or pathogens, a theory known as Darwin's naturalization hypothesis. Here we analyze a complete list of seed-plant species that have been introduced to New Zealand and find that those with congeneric relatives are significantly more, not less, likely to naturalize--perhaps because they share with their native relatives traits that pre-adapt them to their new environment.

  18. A maximum hypothesis of transpiration

    NASA Astrophysics Data System (ADS)

    Wang, Jingfeng; Bras, Rafael L.; Lerdau, Manuel; Salvucci, Guido D.

    2007-09-01

    We hypothesize that the system of liquid water in leaf tissues and the water vapor in the atmosphere tends to evolve towards a potential equilibrium as quickly as possible by maximization of the transpiration rate. We make two assumptions in formulating the transpiration rate: (1) stomatal aperture is directly controlled by guard cell turgor (or leaf water potential); (2) CO2 flux can be used as a nonparametric equivalent of stomatal conductance for a given stomatal function (not necessarily optimal in terms of the water use efficiency for photosynthesis). Transpiration is then expressed as a function of leaf temperature, CO2 flux (as a surrogate of stomatal conductance), and sensible heat flux characterizing the transport mechanism at a given level of radiative energy input. Maximization of transpiration constrained by the energy balance equation leads to vanishing derivatives of transpiration with respect to leaf temperature and CO2 flux. We have obtained observational evidence in support of the proposed hypothesis.

  19. The selection-arena hypothesis.

    PubMed

    Stearns, S C

    1987-01-01

    The selection arena hypothesis offers one answer to a puzzling question. Why do some organisms produce many more fertilized zygotes than are actually reared to hatching, birth, or release-then neglect, discard, resorb, or eat some of them, or allow them to eat each other? It makes four assumptions: (1) zygotes are cheap; (2) after conception the investment of parental time, energy, or risk into offspring continues; (3) offspring vary in fitness; (4) variation in offspring fitness can be identified by the mother at an early stage of the life cycle. If these assumptions hold, then one general prediction follows: the parent should overproduce zygotes, identify those with lower expected fitness, then either kill and reabsorb them, let them be eaten by sibs, or simply stop feeding them in order to invest in more promising offspring. The explanation appears to apply to a wide range of phenomena whose common cause had not previously been appreciated. These include: (1) polyovulation in some bats, tenrecs, the plains viscacha, and the pronghorn antelope; (2) cases of recurrent, consecutive, spontaneous abortions in humans; (3) some cases of surplus flower production and fruit abortion; (4) sex-ratio adjustment in red deer, mice, and coypus; (5) some types of cannibalism, including possible cases in mice, sharks, and wasps. Some cases that might be explained by the selection arena hypothesis are also plausibly explained by other causes, including bet-hedging reproductive investment in the face of unpredictable food supplies, and inter-specific or inter-familial aggression as an alternative to parent-offspring or sib-sib cannibalism. PMID:2961604

  20. Thermal image analysis for detecting facemask leakage

    NASA Astrophysics Data System (ADS)

    Dowdall, Jonathan B.; Pavlidis, Ioannis T.; Levine, James

    2005-03-01

    Due to the modern advent of near ubiquitous accessibility to rapid international transportation the epidemiologic trends of highly communicable diseases can be devastating. With the recent emergence of diseases matching this pattern, such as Severe Acute Respiratory Syndrome (SARS), an area of overt concern has been the transmission of infection through respiratory droplets. Approved facemasks are typically effective physical barriers for preventing the spread of viruses through droplets, but breaches in a mask"s integrity can lead to an elevated risk of exposure and subsequent infection. Quality control mechanisms in place during the manufacturing process insure that masks are defect free when leaving the factory, but there remains little to detect damage caused by transportation or during usage. A system that could monitor masks in real-time while they were in use would facilitate a more secure environment for treatment and screening. To fulfill this necessity, we have devised a touchless method to detect mask breaches in real-time by utilizing the emissive properties of the mask in the thermal infrared spectrum. Specifically, we use a specialized thermal imaging system to detect minute air leakage in masks based on the principles of heat transfer and thermodynamics. The advantage of this passive modality is that thermal imaging does not require contact with the subject and can provide instant visualization and analysis. These capabilities can prove invaluable for protecting personnel in scenarios with elevated levels of transmission risk such as hospital clinics, border check points, and airports.

  1. Theory and Application of Magnetic Flux Leakage Pipeline Detection.

    PubMed

    Shi, Yan; Zhang, Chao; Li, Rui; Cai, Maolin; Jia, Guanwei

    2015-12-10

    Magnetic flux leakage (MFL) detection is one of the most popular methods of pipeline inspection. It is a nondestructive testing technique which uses magnetic sensitive sensors to detect the magnetic leakage field of defects on both the internal and external surfaces of pipelines. This paper introduces the main principles, measurement and processing of MFL data. As the key point of a quantitative analysis of MFL detection, the identification of the leakage magnetic signal is also discussed. In addition, the advantages and disadvantages of different identification methods are analyzed. Then the paper briefly introduces the expert systems used. At the end of this paper, future developments in pipeline MFL detection are predicted.

  2. Theory and Application of Magnetic Flux Leakage Pipeline Detection

    PubMed Central

    Shi, Yan; Zhang, Chao; Li, Rui; Cai, Maolin; Jia, Guanwei

    2015-01-01

    Magnetic flux leakage (MFL) detection is one of the most popular methods of pipeline inspection. It is a nondestructive testing technique which uses magnetic sensitive sensors to detect the magnetic leakage field of defects on both the internal and external surfaces of pipelines. This paper introduces the main principles, measurement and processing of MFL data. As the key point of a quantitative analysis of MFL detection, the identification of the leakage magnetic signal is also discussed. In addition, the advantages and disadvantages of different identification methods are analyzed. Then the paper briefly introduces the expert systems used. At the end of this paper, future developments in pipeline MFL detection are predicted. PMID:26690435

  3. Atlantic multi-decadal oscillation covaries with Agulhas leakage

    PubMed Central

    Biastoch, Arne; Durgadoo, Jonathan V.; Morrison, Adele K.; van Sebille, Erik; Weijer, Wilbert; Griffies, Stephen M.

    2015-01-01

    The interoceanic transfer of seawater between the Indian Ocean and the Atlantic, ‘Agulhas leakage', forms a choke point for the overturning circulation in the global ocean. Here, by combining output from a series of high-resolution ocean and climate models with in situ and satellite observations, we construct a time series of Agulhas leakage for the period 1870–2014. The time series demonstrates the impact of Southern Hemisphere westerlies on decadal timescales. Agulhas leakage shows a correlation with the Atlantic Multi-decadal Oscillation on multi-decadal timescales; the former leading by 15 years. This is relevant for climate in the North Atlantic. PMID:26656850

  4. The Over-Pruning Hypothesis of Autism

    ERIC Educational Resources Information Center

    Thomas, Michael S. C.; Davis, Rachael; Karmiloff-Smith, Annette; Knowland, Victoria C. P.; Charman, Tony

    2016-01-01

    This article outlines the "over-pruning hypothesis" of autism. The hypothesis originates in a neurocomputational model of the regressive sub-type (Thomas, Knowland & Karmiloff-Smith, 2011a, 2011b). Here we develop a more general version of the over-pruning hypothesis to address heterogeneity in the timing of manifestation of ASD,…

  5. Multijurisdictional economies, the Tiebout Hypothesis, and sorting

    PubMed Central

    Wooders, Myrna H.

    1999-01-01

    The Tiebout Hypothesis asserts that, when it is efficient to have multiple jurisdictions providing local public goods, then competition between jurisdictions for residents will lead to a near-optimal outcome. Research from cooperative game theory both provides a foundation for the hypothesis and extends the hypothesis to diverse situations where small groups of participants are effective. PMID:10485868

  6. The venom optimization hypothesis revisited.

    PubMed

    Morgenstern, David; King, Glenn F

    2013-03-01

    Animal venoms are complex chemical mixtures that typically contain hundreds of proteins and non-proteinaceous compounds, resulting in a potent weapon for prey immobilization and predator deterrence. However, because venoms are protein-rich, they come with a high metabolic price tag. The metabolic cost of venom is sufficiently high to result in secondary loss of venom whenever its use becomes non-essential to survival of the animal. The high metabolic cost of venom leads to the prediction that venomous animals may have evolved strategies for minimizing venom expenditure. Indeed, various behaviors have been identified that appear consistent with frugality of venom use. This has led to formulation of the "venom optimization hypothesis" (Wigger et al. (2002) Toxicon 40, 749-752), also known as "venom metering", which postulates that venom is metabolically expensive and therefore used frugally through behavioral control. Here, we review the available data concerning economy of venom use by animals with either ancient or more recently evolved venom systems. We conclude that the convergent nature of the evidence in multiple taxa strongly suggests the existence of evolutionary pressures favoring frugal use of venom. However, there remains an unresolved dichotomy between this economy of venom use and the lavish biochemical complexity of venom, which includes a high degree of functional redundancy. We discuss the evidence for biochemical optimization of venom as a means of resolving this conundrum.

  7. Alien abduction: a medical hypothesis.

    PubMed

    Forrest, David V

    2008-01-01

    In response to a new psychological study of persons who believe they have been abducted by space aliens that found that sleep paralysis, a history of being hypnotized, and preoccupation with the paranormal and extraterrestrial were predisposing experiences, I noted that many of the frequently reported particulars of the abduction experience bear more than a passing resemblance to medical-surgical procedures and propose that experience with these may also be contributory. There is the altered state of consciousness, uniformly colored figures with prominent eyes, in a high-tech room under a round bright saucerlike object; there is nakedness, pain and a loss of control while the body's boundaries are being probed; and yet the figures are thought benevolent. No medical-surgical history was apparently taken in the above mentioned study, but psychological laboratory work evaluated false memory formation. I discuss problems in assessing intraoperative awareness and ways in which the medical hypothesis could be elaborated and tested. If physicians are causing this syndrome in a percentage of patients, we should know about it; and persons who feel they have been abducted should be encouraged to inform their surgeons and anesthesiologists without challenging their beliefs.

  8. Hypothesis: neoplasms in myotonic dystrophy

    PubMed Central

    Hilbert, James E.; Martens, William; Thornton, Charles A.; Moxley, Richard T.; Greene, Mark H.

    2011-01-01

    Tumorigenesis is a multi-step process due to an accumulation of genetic mutations in multiple genes in diverse pathways which ultimately lead to loss of control over cell growth. It is well known that inheritance of rare germline mutations in genes involved in tumorigenesis pathways confer high lifetime risk of neoplasia in affected individuals. Furthermore, a substantial number of multiple malformation syndromes include cancer susceptibility in their phenotype. Studies of the mechanisms underlying these inherited syndromes have added to the understanding of both normal development and the pathophysiology of carcinogenesis. Myotonic dystrophy (DM) represents a group of autosomal dominant, multisystemic diseases that share the clinical features of myotonia, muscle weakness, and early-onset cataracts. Myotonic dystrophy type 1 (DM1) and myotonic dystrophy type 2 (DM2) result from unstable nucleotide repeat expansions in their respective genes. There have been multiple reports of tumors in individuals with DM, most commonly benign calcifying cutaneous tumors known as pilomatricomas. We provide a summary of the tumors reported in DM and a hypothesis for a possible mechanism of tumorigenesis. We hope to stimulate further study into the potential role of DM genes in tumorigenesis, and help define DM pathogenesis, and facilitate developing novel treatment modalities. PMID:19642006

  9. The oxidative hypothesis of senescence.

    PubMed

    Gilca, M; Stoian, I; Atanasiu, V; Virgolici, B

    2007-01-01

    The oxidative hypothesis of senescence, since its origin in 1956, has garnered significant evidence and growing support among scientists for the notion that free radicals play an important role in ageing, either as "damaging" molecules or as signaling molecules. Age-increasing oxidative injuries induced by free radicals, higher susceptibility to oxidative stress in short-lived organisms, genetic manipulations that alter both oxidative resistance and longevity and the anti-ageing effect of caloric restriction and intermittent fasting are a few examples of accepted scientific facts that support the oxidative theory of senescence. Though not completely understood due to the complex "network" of redox regulatory systems, the implication of oxidative stress in the ageing process is now well documented. Moreover, it is compatible with other current ageing theories (e.g, those implicating the mitochondrial damage/mitochondrial-lysosomal axis, stress-induced premature senescence, biological "garbage" accumulation, etc). This review is intended to summarize and critically discuss the redox mechanisms involved during the ageing process: sources of oxidant agents in ageing (mitochondrial -electron transport chain, nitric oxide synthase reaction- and non-mitochondrial- Fenton reaction, microsomal cytochrome P450 enzymes, peroxisomal beta -oxidation and respiratory burst of phagocytic cells), antioxidant changes in ageing (enzymatic- superoxide dismutase, glutathione-reductase, glutathion peroxidase, catalase- and non-enzymatic glutathione, ascorbate, urate, bilirubine, melatonin, tocopherols, carotenoids, ubiquinol), alteration of oxidative damage repairing mechanisms and the role of free radicals as signaling molecules in ageing.

  10. Cerebrospinal Fluid Leakage after Thoracic Decompression

    PubMed Central

    Hu, Pan-Pan; Liu, Xiao-Guang; Yu, Miao

    2016-01-01

    Objective: The objective of this study is to review cerebrospinal fluid leakage (CSFL) after thoracic decompression and describe its regular and special features. Data Sources: Literature cited in this review was retrieved from PubMed and Medline and was primarily published during the last 10 years. “Cerebrospinal fluid”, “leakage”, “dural tears”, and “thoracic decompression” were the indexed terms. Relevant citations in the retrieved articles were also screened to include more data. Study Selection: All retrieved literature was scrutinized, and four categories were recorded: incidence and risk factors, complications, treatment modalities, and prognosis. Results: CSFL is much more frequent after thoracic decompression than after cervical and lumbar spinal surgeries. Its occurrence is related to many clinical factors, especially the presence of ossified ligaments and the adhesion of the dural sac. While its impact on the late neurological recovery is currently controversial, CSFL increases the risk of other perioperative complications, such as low intracranial pressure symptoms, infection, and vascular events. The combined use of primary repairs during the operation and conservative treatment postoperatively is generally effective for most CSFL cases, whereas lumbar drains and reoperations should be implemented as rescue options for refractory cases only. Conclusions: CSFL after thoracic decompression has not been specifically investigated, so the present study provides a systematic and comprehensive review of the issue. CSFL is a multi-factor-related complication, and pathological factors play a decisive role. The importance of CSFL is in its impact on the increased risk of other complications during the postoperative period. Methods to prevent these complications are in need. In addition, though the required treatment resources are not special for CSFL after thoracic decompression, most CSFL cases are conservatively curable, and surgeons should be

  11. 49 CFR 192.706 - Transmission lines: Leakage surveys.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... TRANSPORTATION OF NATURAL AND OTHER GAS BY PIPELINE: MINIMUM FEDERAL SAFETY STANDARDS Maintenance § 192.706... transports gas in conformity with § 192.625 without an odor or odorant, leakage surveys using leak...

  12. Cement Leakage into Adjacent Vertebral Body Following Percutaneous Vertebroplasty

    PubMed Central

    Park, Jae Hoo; Kim, Hyeun Sung

    2016-01-01

    Percutaneous vertebroplasty (PV) is a minimally invasive procedure for osteoporotic vertebral compression fractures that fail to respond to conventional conservative treatment. It significantly improves intolerable back pain within hours, and has a low complication rate. Although rare, PV is not free of complications, most of which are directly related to cement leakage. Because of its association with new adjacent fracture, the importance of cement leakage into the adjacent disc space is paramount. Here, we report an interesting case of cement leakage into the adjacent upper vertebral body as well as disc space following PV. To the best of our knowledge, there has been no report of cement leakage into the adjacent vertebral body following PV. This rare case is presented along with a review of the literature. PMID:27437018

  13. 21 CFR 870.2640 - Portable leakage current alarm.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... (CONTINUED) MEDICAL DEVICES CARDIOVASCULAR DEVICES Cardiovascular Monitoring Devices § 870.2640 Portable... the electrical leakage current between any two points of an electrical system and to sound an alarm...

  14. 21 CFR 870.2640 - Portable leakage current alarm.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... (CONTINUED) MEDICAL DEVICES CARDIOVASCULAR DEVICES Cardiovascular Monitoring Devices § 870.2640 Portable... the electrical leakage current between any two points of an electrical system and to sound an alarm...

  15. 21 CFR 870.2640 - Portable leakage current alarm.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... (CONTINUED) MEDICAL DEVICES CARDIOVASCULAR DEVICES Cardiovascular Monitoring Devices § 870.2640 Portable... the electrical leakage current between any two points of an electrical system and to sound an alarm...

  16. 21 CFR 870.2640 - Portable leakage current alarm.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... (CONTINUED) MEDICAL DEVICES CARDIOVASCULAR DEVICES Cardiovascular Monitoring Devices § 870.2640 Portable... the electrical leakage current between any two points of an electrical system and to sound an alarm...

  17. Defect-Enabled Electrical Current Leakage in Ultraviolet Light-Emitting Diodes

    DOE PAGES

    Moseley, Michael William; Allerman, Andrew A.; Crawford, Mary H.; Wierer, Jonathan; Smith, Michael L.; Biedermann, Laura

    2015-04-13

    The AlGaN materials system offers a tunable, ultra-wide bandgap that is exceptionally useful for high-power electronics and deep ultraviolet optoelectronics. Moseley et al. (pp. 723–726) investigate a structural defect known as an open-core threading dislocation or ''nanopipe'' that is particularly detrimental to devices that employ these materials. Furthermore, an AlGaN thin film was synthesized using metal-organic chemical-vapor deposition. Electrical current leakage is detected at a discrete point using a conductive atomic-force microscope (CAFM). However, no physical feature or abnormality at this location was visible by an optical microscope. The AlGaN thin film was then etched in hot phosphoric acid, andmore » the same location that was previously analyzed was revisited with the CAFM. The point that previously exhibited electrical current leakage had been decorated with a 1.1 μm wide hexagonal pit, which identified the site of electrical current leakage as a nanopipe and allows these defects to be easily observed by optical microscopy. Moreover, with this nanopipe identification and quantification strategy, the authors were able to correlate decreasing ultraviolet light-emitting diode optical output power with increasing nanopipe density.« less

  18. Air leakage on the postoperative day: powerful factor of postoperative recurrence after thoracoscopic bullectomy

    PubMed Central

    Jeon, Hyun Woo; Kye, Yeo Kon; Kim, Kyung Soo

    2016-01-01

    Background Primary spontaneous pneumothorax (PSP) is a relatively common disorder in young patients. Although various surgical techniques have been introduced, recurrence after video-assisted thoracoscopic surgery (VATS) remains high. The aim of study was to identify the risk factors for postoperative recurrence after thoracoscopic bullectomy in the spontaneous pneumothorax. Methods From January 2011 through March 2013, two hundreds and thirty two patients underwent surgery because of pneumothorax. Patients with a secondary pneumothorax, as well as cases of single port surgery, an open procedure, additional pleural procedure (pleurectomy, pleural abrasion) or lack of medical records were excluded. The records of 147 patients with PSP undergoing 3-port video-assisted thoracoscopic bullectomy with staple line coverage using an absorbable polyglycolic acid (PGA) sheet were retrospectively reviewed. Results The median age was 19 years (range, 11−34 years) with male predominance (87.8%). Median postoperative hospital stay was 3 days (range, 1−10 days) without mortality. Complications were developed in five patients. A total of 24 patients showed postoperative recurrence (16.3%). Younger age less than 17 years old and immediate postoperative air leakage were risk factors for postoperative recurrence after thoracoscopic bullectomy by multivariate analysis. Conclusions Immediate postoperative air leakage was the risk factor for postoperative recurrence. However, further study will be required for the correlation of air leakage with recurrence. PMID:26904217

  19. Defect-Enabled Electrical Current Leakage in Ultraviolet Light-Emitting Diodes

    SciTech Connect

    Moseley, Michael William; Allerman, Andrew A.; Crawford, Mary H.; Wierer, Jonathan; Smith, Michael L.; Biedermann, Laura

    2015-04-13

    The AlGaN materials system offers a tunable, ultra-wide bandgap that is exceptionally useful for high-power electronics and deep ultraviolet optoelectronics. Moseley et al. (pp. 723–726) investigate a structural defect known as an open-core threading dislocation or ''nanopipe'' that is particularly detrimental to devices that employ these materials. Furthermore, an AlGaN thin film was synthesized using metal-organic chemical-vapor deposition. Electrical current leakage is detected at a discrete point using a conductive atomic-force microscope (CAFM). However, no physical feature or abnormality at this location was visible by an optical microscope. The AlGaN thin film was then etched in hot phosphoric acid, and the same location that was previously analyzed was revisited with the CAFM. The point that previously exhibited electrical current leakage had been decorated with a 1.1 μm wide hexagonal pit, which identified the site of electrical current leakage as a nanopipe and allows these defects to be easily observed by optical microscopy. Moreover, with this nanopipe identification and quantification strategy, the authors were able to correlate decreasing ultraviolet light-emitting diode optical output power with increasing nanopipe density.

  20. Segmentation and the pairing hypothesis.

    PubMed

    Bragason, Orn

    2004-09-30

    The effect of stimulus contiguity and response contingency on responding in chain schedules was examined in two experiments. In Experiment 1, four pigeons were trained on two simple three-link chain schedules that alternated within sessions. Initial links were correlated with a variable-interval 30s schedule, and middle and terminal links were correlated with interdependent variable-interval 30s variable-interval 30s schedules. The combined duration of the interdependent schedules summed to 60s. The two chains differed with respect to signaling of the schedule components: a two-stimulus chain had one stimulus paired with the initial link and one stimulus paired with both the middle and the terminal link, while a three-stimulus chain had a different stimulus paired with the each of the three links. The results showed that the two-stimulus chain maintained lower initial-link responding than the three-stimulus chain. In Experiment 2, four pigeons were exposed to three separate conditions, the two- and three-stimulus chains of Experiment 1 and a three-stimulus chain that had a 3s delay to terminal-link entry from the middle-link response that produced it. The two-stimulus chain maintained lower initial-link responding than the three-stimulus chain, as in Experiment 1, and a similar initial-link responding was maintained by the two-stimulus chain and the three-stimulus chain with the delay contingency. The results demonstrate that a stimulus noncontiguous with food can maintain responding that is sometimes greater than a stimulus contiguous with food, depending on the response contingency for terminal-link entry. The results are contrary to the pairing hypothesis of conditioned reinforcement.

  1. Testing the geometric clutch hypothesis.

    PubMed

    Lindemann, Charles B

    2004-12-01

    The Geometric Clutch hypothesis is based on the premise that transverse forces (t-forces) acting on the outer doublets of the eukaryotic axoneme coordinate the action of the dynein motors to produce flagellar and ciliary beating. T-forces result from tension and compression on the outer doublets when a bend is present on the flagellum or cilium. The t-force acts to pry the doublets apart in an active bend, and push the doublets together when the flagellum is passively bent and thus could engage and disengage the dynein motors. Computed simulations of this working mechanism have reproduced the beating pattern of simple cilia and flagella, and of mammalian sperm. Cilia-like beating, with a clearly defined effective and recovery stroke, can be generated using one uniformly applied switching algorithm. When the mechanical properties and dimensions appropriate to a specific flagellum are incorporated into the model the same algorithm can simulate a sea urchin or bull sperm-like beat. The computed model reproduces many of the observed behaviors of real flagella and cilia. The model can duplicate the results of outer arm extraction experiments in cilia and predicted two types of arrest behavior that were verified experimentally in bull sperm. It also successfully predicted the experimentally determined nexin elasticity. Calculations based on live and reactivated sea urchin and bull sperm yielded a value of 0.5 nN/microm for the t-force at the switch-point. This is a force sufficient to overcome the shearing force generated by all the dyneins on one micron of outer doublet. A t-force of this magnitude should produce substantial distortion of the axoneme at the switch-point, especially in spoke or spoke-head deficient motile flagella. This concrete and verifiable prediction is within the grasp of recent advances in imaging technology, specifically cryoelectron microscopy and atomic force microscopy. PMID:15567522

  2. Infantile amnesia: a neurogenic hypothesis.

    PubMed

    Josselyn, Sheena A; Frankland, Paul W

    2012-08-16

    In the late 19th Century, Sigmund Freud described the phenomenon in which people are unable to recall events from early childhood as infantile amnesia. Although universally observed, infantile amnesia is a paradox; adults have surprisingly few memories of early childhood despite the seemingly exuberant learning capacity of young children. How can these findings be reconciled? The mechanisms underlying this form of amnesia are the subject of much debate. Psychological/cognitive theories assert that the ability to maintain detailed, declarative-like memories in the long term correlates with the development of language, theory of mind, and/or sense of "self." However, the finding that experimental animals also show infantile amnesia suggests that this phenomenon cannot be explained fully in purely human terms. Biological explanations of infantile amnesia suggest that protracted postnatal development of key brain regions important for memory interferes with stable long-term memory storage, yet they do not clearly specify which particular aspects of brain maturation are causally related to infantile amnesia. Here, we propose a hypothesis of infantile amnesia that focuses on one specific aspect of postnatal brain development--the continued addition of new neurons to the hippocampus. Infants (humans, nonhuman primates, and rodents) exhibit high levels of hippocampal neurogenesis and an inability to form lasting memories. Interestingly, the decline of postnatal neurogenesis levels corresponds to the emergence of the ability to form stable long-term memory. We propose that high neurogenesis levels negatively regulate the ability to form enduring memories, most likely by replacing synaptic connections in preexisting hippocampal memory circuits.

  3. The viral hypothesis in parkinsonism.

    PubMed

    Elizan, T S; Casals, J

    1983-01-01

    The most crucial unanswered question in Parkinson's disease is its fundamental cause. Since Carlsson's original suggestion that dopamine may be a transmitter in the central nervous system involved in the control of motor function and that it may be involved in the Parkinsonian syndrome (Carlsson, 1959), and the now-classic paper by Ehringer and Hornykiewicz (1960) which definitively showed the significant reduction of dopamine concentration in the neostriatum of cases of idiopathic Parkinson and postencephalitic parkinsonism, the vast amount of work on the subject has focused on the biochemical and pharmacologic correlates of this dopaminergic system failure involving particularly the nigrostriatal pathways. The concept of a specific neurotransmitter deficiency associated with a specific neurological syndrome potentially amenable to replacement therapy, has appropriately generated a considerable degree of clinical and research interest for over 20 years, but, with few exceptions, there has been hardly any focused or concerted research effort on looking at direct causal factors or primary initiating events in this disease process. As in Alzheimer's disease, another of the degenerative diseases of the brain of unknown origin with a specific biochemical substrate, any etiologic hypothesis for Parkinson's disease--whether a virus, an age-related immune system dysfunction, a genetic factor, a "trophic" substance, or a toxin--would have to explain the selective involvement of specific transmitter-defined neuronal pathways, the non-specificity of the brain lesions that define the disease, and the clinical involvement of a sizeable segment of the aging population. Of the several plausible hypotheses mentioned earlier, which are not necessarily mutually exclusive, we would like to critically consider the possibility of a viral cause. PMID:6583315

  4. Biliary leakage after urgent cholecystectomy: Optimization of endoscopic treatment

    PubMed Central

    Ljubičić, Neven; Bišćanin, Alen; Pavić, Tajana; Nikolić, Marko; Budimir, Ivan; Mijić, August; Đuzel, Ana

    2015-01-01

    AIM: To investigate the results of endoscopic treatment of postoperative biliary leakage occurring after urgent cholecystectomy with a long-term follow-up. METHODS: This is an observational database study conducted in a tertiary care center. All consecutive patients who underwent endoscopic retrograde cholangiography (ERC) for presumed postoperative biliary leakage after urgent cholecystectomy in the period between April 2008 and April 2013 were considered for this study. Patients with bile duct transection and biliary strictures were excluded. Biliary leakage was suspected in the case of bile appearance from either percutaneous drainage of abdominal collection or abdominal drain placed at the time of cholecystectomy. Procedural and main clinical characteristics of all consecutive patients with postoperative biliary leakage after urgent cholecystectomy, such as indication for cholecystectomy, etiology and type of leakage, ERC findings and post-ERC complications, were collected from our electronic database. All patients in whom the leakage was successfully treated endoscopically were followed-up after they were discharged from the hospital and the main clinical characteristics, laboratory data and common bile duct diameter were electronically recorded. RESULTS: During a five-year period, biliary leakage was recognized in 2.2% of patients who underwent urgent cholecystectomy. The median time from cholecystectomy to ERC was 6 d (interquartile range, 4-11 d). Endoscopic interventions to manage biliary leakage included biliary stent insertion with or without biliary sphincterotomy. In 23 (77%) patients after first endoscopic treatment bile flow through existing surgical drain ceased within 11 d following biliary therapeutic endoscopy (median, 4 d; interquartile range, 2-8 d). In those patients repeat ERC was not performed and the biliary stent was removed on gastroscopy. In seven (23%) patients repeat ERC was done within one to fourth week after their first ERC

  5. Expedient methods of respiratory protection. II. Leakage tests. Final report

    SciTech Connect

    Cooper, D.W.; Hinds, W.C.; Price, J.M.; Weker, R.; Yee, H.S.

    1983-07-01

    The following readily-available materials were tested on a manikin connected to a breathing simulator to determine the fraction of an approximately 2-..mu..m-diameter aerosol that would leak around the seal of the materials to the manikin's face: cotton/polyester shirt material, cotton handkerchief material, toweling (a wash cloth), a surgical mask (Johnson and Johnson Co., model HRI 8137), and a NIOSH-approved disposable face mask (3M, model number 8710). The leakage tests were performed to supplement the measurements of penetration through the materials, conducted as the first phase of this investigation. The leakage tests were performed with the materials held on to the face by three methods, leakage fractions being determined from comparisons with the penetration of the same aerosol for the materials fully taped to the face. At a breathing rate of 37 liters per minute, mean leakages ranged from 0.0 percent to 63 percent. Mean penetrations exclusive of leakage ranged from 0.6 percent to 39 percent. Use of nylon hosiery material (panty hose) to hold the handkerchief material or the disposable face mask to the face was found to be very effective in preventing leakage. Such a combination could be expected to reduce leakage around the handkerchief to about ten percent or less in practice, and around the mask to less than one percent, offering substantial protection from accidentally generated aerosols. The reduction in leakage around the mask provided by the hosiery material suggests the adaptation and use of such an approach in regular industrial hygiene practice. The third and final phase of this investigation is underway, in which the penetration of the materials by particles with diameters between 0.05 and 0.5 ..mu..m is being measured and the effectiveness of the methods for dose reduction in the presence of radioactive aerosols is being modeled.

  6. New theoretical model and experiments on the leakage of refrigerant mixtures in a tank

    SciTech Connect

    Gao, Z.; Schreiber, W.; Ma, Y.

    1999-07-01

    A theoretical model of the isothermal leakage of refrigerant mixtures from a tank is presented. The model analyzes the isothermal leakage process of non-azeotropic mixture and the influence of leakage ratio on composition shift, vapor quality, and pressure. A simulation based on the model shows: (1) the composition shift caused by vapor leakage is more pronounced than by liquid leakage; (2) with the leakage ratio increasing, the composition shift trend varies with initial mass capacity, particularly when the leakage ratio is greater than 0.8; (3) the pressure drop is pronounced during the vapor leakage, but does not change during liquid leakage unless the leakage ratio is high. A series of leakage experiments are performed in a newly developed experimental system. The theoretical and experimental results match closely.

  7. Energy Efficient High-Pressure Turbine Leakage Technology Report

    NASA Technical Reports Server (NTRS)

    Gardner, W. B.

    1980-01-01

    The leakage test program was one of such supporting technology programs structured to provide guidance to the Energy Efficient Engine High Pressure Turbine Component Design Effort. Leakage reduction techniques were identified and evaluated. Test models were used to simulate component leak paths and to evaluate leakage reduction techniques. These models simulated the blade/disk attachment, the vane inner platform attachment, and the vane outer platform attachment combined with the blade outer airseal. Disk blade attachment testing indicated that leakage in this area could be reduced to very low levels by paying careful attention to the tolerances along the contact surface between the blade vibration damper and the blade platform contact surface. The aim of feather seal testing was to achieve a goal for an effective leakage gap of one mil (.001 inch) per inch of feather seal length. Results indicated that effective gaps even below the goal level were achievable by (1) maintaining close tolerances between feather seals and their slots to minimize end gaps and limit seal rotation, (2) avoiding feather seal overlap, and (3) minimizing feather seal intersections. W seals were shown to be effective leakage control devices. Wire rope, in its present state of development, was shown not to be an effective sealing concept for application to the component design.

  8. Field size dependent mapping of medical linear accelerator radiation leakage.

    PubMed

    Bezin, Jérémi Vũ; Veres, Attila; Lefkopoulos, Dimitri; Chavaudra, Jean; Deutsch, Eric; de Vathaire, Florent; Diallo, Ibrahima

    2015-03-01

    The purpose of this study was to investigate the suitability of a graphics library based model for the assessment of linear accelerator radiation leakage. Transmission through the shielding elements was evaluated using the build-up factor corrected exponential attenuation law and the contribution from the electron guide was estimated using the approximation of a linear isotropic radioactive source. Model parameters were estimated by a fitting series of thermoluminescent dosimeter leakage measurements, achieved up to 100 cm from the beam central axis along three directions. The distribution of leakage data at the patient plane reflected the architecture of the shielding elements. Thus, the maximum leakage dose was found under the collimator when only one jaw shielded the primary beam and was about 0.08% of the dose at isocentre. Overall, we observe that the main contributor to leakage dose according to our model was the electron beam guide. Concerning the discrepancies between the measurements used to calibrate the model and the calculations from the model, the average difference was about 7%. Finally, graphics library modelling is a readily and suitable way to estimate leakage dose distribution on a personal computer. Such data could be useful for dosimetric evaluations in late effect studies.

  9. Platelet function alterations in dengue are associated with plasma leakage.

    PubMed

    Michels, M; Alisjahbana, B; De Groot, P G; Indrati, A R; Fijnheer, R; Puspita, M; Dewi, I M W; van de Wijer, L; de Boer, E M S; Roest, M; van der Ven, A J A M; de Mast, Q

    2014-08-01

    Severe dengue is characterised by thrombocytopenia, plasma leakage and bleeding. Platelets are important for preservation of endothelial integrity. We hypothesised that platelet activation with secondary platelet dysfunction contribute to plasma leakage. In adult Indonesian patients with acute dengue, we measured platelet activation status and the response to the platelet agonist TRAP using flow cytometer-based assays. Patients were monitored daily for plasma leakage by ultrasonography. Acute dengue was associated with platelet activation with an increased expression of the activated fibrinogen receptor (αIIbβ3), the lysosomal marker CD63 and the alpha-granule marker CD62P (P-selectin). Upon maximal platelet activation by TRAP, platelet function defects were observed with a significantly reduced maximal activated αIIbβ3 and CD63 expression and reduced platelet-monocyte and platelet-neutrophil complexes. Patients in the lowest tertile of activated αIIbβ3 and CD63 expression had an odds ratio for plasma leakage of 5.2 (95% confidence interval [CI] 1.3-22.7) and 3.9 (95% CI 1.1-13.7), respectively, compared to the highest tertile. Platelet-derived serotonin has previously been related to plasma leakage and we found increased intra-platelet serotonin concentrations in our patients. In conclusion, platelet activation with platelet function alterations can be found in patients with acute dengue and this may contribute to dengue-associated plasma leakage.

  10. Acute Alcohol Intoxication-Induced Microvascular Leakage

    PubMed Central

    Doggett, Travis M.; Breslin, Jerome W.

    2014-01-01

    Background Alcohol intoxication can increase inflammation and worsen injury, yet the mechanisms involved are not clear. We investigated whether acute alcohol intoxication elevates microvascular permeability, and investigated potential signaling mechanisms in endothelial cells that may be involved. Methods Conscious rats received a 2.5 g/kg alcohol bolus via gastric catheters to produce acute intoxication. Microvascular leakage of intravenously administered FITC-albumin from the mesenteric microcirculation was assessed by intravital microscopy. Endothelial-specific mechanisms were studied using cultured endothelial cell monolayers. Transendothelial electrical resistance (TER) served as an index of barrier function, before and after treatment with alcohol or its metabolite acetaldehyde. Pharmacologic agents were used to test the roles of alcohol metabolism, oxidative stress, p38 mitogen-activated protein (MAP) kinase, myosin light chain kinase (MLCK), rho kinase (ROCK), and exchange protein activated by cAMP (Epac). VE-cadherin localization was investigated to assess junctional integrity. Rac1 and RhoA activation were assessed by ELISA assays. Results Alcohol significantly increased FITC-albumin extravasation from the mesenteric microcirculation. Alcohol also significantly decreased TER and disrupted VE-cadherin organization at junctions. Acetaldehyde significantly decreased TER, but inhibition of ADH or application of a superoxide dismutase mimetic failed to prevent alcohol-induced decreases in TER. Inhibition of p38 MAP kinase, but not MLCK or ROCK, significantly attenuated the alcohol-induced barrier dysfunction. Alcohol rapidly decreased GTP-bound Rac1 but not RhoA during the drop in TER. Activation of Epac increased TER, but did not prevent alcohol from decreasing TER. However, activation of Epac after initiation of alcohol-induced barrier dysfunction quickly resolved TER to baseline levels. Conclusions Our results suggest that alcohol intoxication increases

  11. THERMAL REGAIN FROM DISPLACEMENT OF DUCT LEAKAGE WITHIN INSULATION.

    SciTech Connect

    ANDREWS,J.W.

    2002-05-01

    In one type of duct efficiency retrofit, additional insulation is added to a duct system that is already insulated. For example, a layer of R-4 insulation might be: added to a duct system that already has R-4 installed. It is possible that--either by chance or by design--the add-on layer, while not stopping duct leaks, might cause the leakage air to flow longitudinally for a distance, parallel to the duct, before it finds a way out of the newly added outer layer. This could happen by chance if the outer and inner layers of insulation have seams at different locations. Perhaps more usefully, if such longitudinal displacement of the leakage air turned out to be useful, it might be designed into the makeup of the outer insulation layer intended to be used in the retrofit. It is plausible that this leakage air might serve a useful function in keeping the insulation layer warmer (or, in the air-conditioning mode, cooler) than it would be in the absence of the leakage. By being held close to the ducts for a while, it might establish an artificially warmer (or cooler, in air conditioning) zone around the ducts. To the extent that this effect would reduce the heat losses from the ducts, the leakage should be credited with a ''thermal regain'' in the same way that leakage into buffer zones is credited with thermal regain when the leakage air warms (or cools) the buffer zone relative to the temperature it would have in the absence of such duct leakage. The purpose of this report is to investigate whether and to what extent such thermal regain exists. The model developed below applies to a situation where there are two distinct layers of insulation around the duct, with leakage air moving between them in a longitudinal direction for a distance before it finds its way out from the outer insulation layer. It may also apply approximately where there is a single insulation layer with an air barrier on the outside. Leakage air may pass into the insulation itself and thence

  12. 47 CFR 76.1706 - Signal leakage logs and repair records.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 47 Telecommunication 4 2012-10-01 2012-10-01 false Signal leakage logs and repair records. 76.1706... leakage logs and repair records. Cable operators shall maintain a log showing the date and location of each leakage source identified pursuant to § 76.614, the date on which the leakage was repaired,...

  13. 47 CFR 76.1706 - Signal leakage logs and repair records.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 47 Telecommunication 4 2011-10-01 2011-10-01 false Signal leakage logs and repair records. 76.1706... leakage logs and repair records. Cable operators shall maintain a log showing the date and location of each leakage source identified pursuant to § 76.614, the date on which the leakage was repaired,...

  14. 47 CFR 76.1706 - Signal leakage logs and repair records.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 47 Telecommunication 4 2013-10-01 2013-10-01 false Signal leakage logs and repair records. 76.1706... leakage logs and repair records. Cable operators shall maintain a log showing the date and location of each leakage source identified pursuant to § 76.614, the date on which the leakage was repaired,...

  15. 47 CFR 76.1706 - Signal leakage logs and repair records.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 47 Telecommunication 4 2014-10-01 2014-10-01 false Signal leakage logs and repair records. 76.1706... leakage logs and repair records. Cable operators shall maintain a log showing the date and location of each leakage source identified pursuant to § 76.614, the date on which the leakage was repaired,...

  16. The Leakage Risk Monetization Model for Geologic CO2 Storage.

    PubMed

    Bielicki, Jeffrey M; Pollak, Melisa F; Deng, Hang; Wilson, Elizabeth J; Fitts, Jeffrey P; Peters, Catherine A

    2016-05-17

    We developed the Leakage Risk Monetization Model (LRiMM) which integrates simulation of CO2 leakage from geologic CO2 storage reservoirs with estimation of monetized leakage risk (MLR). Using geospatial data, LRiMM quantifies financial responsibility if leaked CO2 or brine interferes with subsurface resources, and estimates the MLR reduction achievable by remediating leaks. We demonstrate LRiMM with simulations of 30 years of injection into the Mt. Simon sandstone at two locations that differ primarily in their proximity to existing wells that could be leakage pathways. The peak MLR for the site nearest the leakage pathways ($7.5/tCO2) was 190x larger than for the farther injection site, illustrating how careful siting would minimize MLR in heavily used sedimentary basins. Our MLR projections are at least an order of magnitude below overall CO2 storage costs at well-sited locations, but some stakeholders may incur substantial costs. Reliable methods to detect and remediate leaks could further minimize MLR. For both sites, the risk of CO2 migrating to potable aquifers or reaching the atmosphere was negligible due to secondary trapping, whereby multiple impervious sedimentary layers trap CO2 that has leaked through the primary seal of the storage formation.

  17. Suppression and control of leakage field in electromagnetic helical microwiggler

    SciTech Connect

    Ohigashi, N.; Tsunawaki, Y.; Imasaki, K.

    1995-12-31

    Shortening the period of electromagnetic wiggler introduces both the radical increase of the leakage field and the decrease of the field in the gap region. The leakage field is severer problem in planar electromagnetic wiggler than in helical wiggler. Hence, in order to develop a short period electromagnetic wiggler, we have adopted {open_quotes}three poles per period{close_quotes} type electromagnetic helical microwiggler. In this work, we inserted the permanent magnet (PM) blocks with specific magnetized directions in the space between magnetic poles, for suppressing the leakage field flowing out from a pole face to the neighboring pole face. These PM-blocks must have higher intrinsic coersive force than saturation field of pole material. The gap field due to each pole is adjustable by controlling the leakage fields, that is, controlling the position of each iron screw set in each retainer fixing the PM-blocks. At present time, a test wiggler with period 7.8mm, periodical number 10 and gap length 4.6mm has been manufactured. Because the ratio of PM-block aperture to gap length is important parameter to suppress the leakage field, the parameter has been surveyed experimentally for PM-blocks with several dimensions of aperture. The field strength of 3-5kG (K=0.2-0.4) would be expected in the wiggler.

  18. Controlling leakage losses in subwavelength grating silicon metamaterial waveguides.

    PubMed

    Sarmiento-Merenguel, J Darío; Ortega-Moñux, Alejandro; Fédéli, Jean-Marc; Wangüemert-Pérez, J Gonzalo; Alonso-Ramos, Carlos; Durán-Valdeiglesias, Elena; Cheben, Pavel; Molina-Fernández, Íñigo; Halir, Robert

    2016-08-01

    Subwavelength gratings (SWG) are photonic structures with a period small enough to suppress diffraction, thereby acting as artificial dielectric materials, also called all-dielectric metamaterials. This property has been exploited in many high-performance photonic integrated devices in the silicon-on-insulator (SOI) platform. While SWG waveguides are theoretically lossless, they may exhibit leakage penalty to the substrate due to a combination of reduced modal confinement and finite thickness of the buried oxide (BOX) layer. In this Letter, for the first time, to the best of our knowledge, we analyze substrate leakage losses in SWG waveguides. We establish a direct relation between the effective index of the waveguide mode and the leakage losses which, remarkably, is independent of the geometric parameters of the SWG waveguide. This universal relation is demonstrated both numerically and experimentally, and it provides practical design guidelines to mitigate leakage losses. For BOX thicknesses of 2 and 3 μm, we find negligible leakage losses when the mode effective index is higher than 1.65 and 1.55, respectively. PMID:27472589

  19. Gas-path leakage seal for a gas turbine

    DOEpatents

    Wolfe, C.E.; Dinc, O.S.; Bagepalli, B.S.; Correia, V.H.; Aksit, M.F.

    1996-04-23

    A gas-path leakage seal is described for generally sealing a gas-path leakage-gap between spaced-apart first and second members of a gas turbine (such as combustor casing segments). The seal includes a generally imperforate foil-layer assemblage which is generally impervious to gas and is located in the leakage-gap. The seal also includes a cloth-layer assemblage generally enclosingly contacting the foil-layer assemblage. In one seal, the first edge of the foil-layer assemblage is left exposed, and the foil-layer assemblage resiliently contacts the first member near the first edge to reduce leakage in the ``plane`` of the cloth-layer assemblage under conditions which include differential thermal growth of the two members. In another seal, such leakage is reduced by having a first weld-bead which permeates the cloth-layer assemblage, is attached to the metal-foil-layer assemblage near the first edge, and unattachedly contacts the first member. 4 figs.

  20. Gas-path leakage seal for a gas turbine

    DOEpatents

    Wolfe, Christopher E.; Dinc, Osman S.; Bagepalli, Bharat S.; Correia, Victor H.; Aksit, Mahmut F.

    1996-01-01

    A gas-path leakage seal for generally sealing a gas-path leakage-gap between spaced-apart first and second members of a gas turbine (such as combustor casing segments). The seal includes a generally imperforate foil-layer assemblage which is generally impervious to gas and is located in the leakage-gap. The seal also includes a cloth-layer assemblage generally enclosingly contacting the foil-layer assemblage. In one seal, the first edge of the foil-layer assemblage is left exposed, and the foil-layer assemblage resiliently contacts the first member near the first edge to reduce leakage in the "plane" of the cloth-layer assemblage under conditions which include differential thermal growth of the two members. In another seal, such leakage is reduced by having a first weld-bead which permeates the cloth-layer assemblage, is attached to the metal-foil-layer assemblage near the first edge, and unattachedly contacts the first member.

  1. Radio frequency leakage current from unipolar laparoscopic electrocoagulators.

    PubMed

    DiNovo, J A

    1983-09-01

    Radio frequency (RF) leakage current has been suspected of causing accidental tissue burns associated with laparoscopic electrocoagulation used for tubal sterilization. A study was done to determine the levels of capacitively coupled RF leakage current from six unipolar laparoscopes manufactured by five companies. Leakage current values ranging from less than 100 mA to over 550 mA were measured at electrosurgical unit power settings of up to 150 w into 1,000 ohms. These levels represent 24-62% of the total electrosurgical current generated by the electrosurgical units. Using a criterion for tissue injury of 100 mA/sq cm applied for ten seconds, leakage current levels exceeding 400 mA are capable of producing burns either at the abdominal wall or to internal organs that accidentally come into contact with the body of the laparoscope. One of the six devices tested had leakage current levels higher than 400 mA at power settings lower than 100 w. Capacitance measurements between the unipolar laparoscope body and the forceps ranged from 53 to 140 picofarads.

  2. Leakage Flow Characteristics in Expander for CO2 Refrigeration Cycle

    NASA Astrophysics Data System (ADS)

    Fukuta, Mitsuhiro; Adachi, Masaaki; Yanagisawa, Tadashi; Ogi, Yasuhiro

    Carbon dioxide (CO2) is considered to be an alternative to HFC refrigerants due to its non-flammability, non-toxicity and small global warming potential. To improve the performance of the CO2 refrigeration cycle, using an expander as an expansion device to recover a throttling loss has been examined. Since an inlet condition of the expander is supercritical and an exit is subcritical, leakage through a narrow clearance in the expander becomes a transcritical flow where the condition changes from the supercritical to the subcritical. It is necessary to clarify the characteristics of the transcritical leakage flow through the narrow clearance, because the leakage flow has serious influence on the expander performance. In this study, the transcritical leakage flow is modeled analytically and the flow characteristic is examined by the model. The calculated mass flow rate agrees with the experimental one. It is found that frictional loss accounts for a half of pressure drop both in the supercritical and two phase region at any inlet temperature tested in this study. In addition, the sealing effect of oil on the transcritical leakage flow rate is shown to be little.

  3. Percutaneous Management of Postoperative Duodenal Stump Leakage with Foley Catheter

    SciTech Connect

    Oh, Jung Suk Lee, Hae Giu Chun, Ho Jong; Choi, Byung Gil; Lee, Sang Hoon; Hahn, Seong Tai; Ohm, Joon Young

    2013-10-15

    Purpose: This study was designed to evaluate retrospectively the safety and efficacy of the percutaneous management of duodenal stump leakage with a Foley catheter after subtotal gastrectomy. Methods: Ten consecutive patients (M:F = 9:1, median age: 64 years) were included in this retrospective study. The duodenal stump leakages were diagnosed in all the patients within a median of 10 days (range, 6-20). At first, the patients underwent percutaneous drainage on the day of or the day after confirmation of the presence of duodenal stump leakage, and then the Foley catheters were replaced at a median of 9 days (range, 6-38) after the percutaneous drainage. Results: Foley catheters were placed successfully in the duodenal lumen of all the patients under a fluoroscopic guide. No complication was observed during and after the procedures in all the patients. All of the patients started a regular diet 1 day after the Foley catheter placement. The patients were discharged at a median of 7 days (range, 5-14) after the Foley catheter placement. The catheters were removed in an outpatient clinic 10-58 days (median, 28) after the Foley catheter placement. Conclusions: Fluoroscopy-guided percutaneous Foley catheter placement may be a safe and effective treatment option for postoperative duodenal stump leakage and may allow for shorter hospital stays, earlier oral intake, and more effective control of leakage sites.

  4. Radio frequency leakage current from unipolar laparoscopic electrocoagulators.

    PubMed

    DiNovo, J A

    1983-09-01

    Radio frequency (RF) leakage current has been suspected of causing accidental tissue burns associated with laparoscopic electrocoagulation used for tubal sterilization. A study was done to determine the levels of capacitively coupled RF leakage current from six unipolar laparoscopes manufactured by five companies. Leakage current values ranging from less than 100 mA to over 550 mA were measured at electrosurgical unit power settings of up to 150 w into 1,000 ohms. These levels represent 24-62% of the total electrosurgical current generated by the electrosurgical units. Using a criterion for tissue injury of 100 mA/sq cm applied for ten seconds, leakage current levels exceeding 400 mA are capable of producing burns either at the abdominal wall or to internal organs that accidentally come into contact with the body of the laparoscope. One of the six devices tested had leakage current levels higher than 400 mA at power settings lower than 100 w. Capacitance measurements between the unipolar laparoscope body and the forceps ranged from 53 to 140 picofarads. PMID:6226780

  5. The Leakage Risk Monetization Model for Geologic CO2 Storage.

    PubMed

    Bielicki, Jeffrey M; Pollak, Melisa F; Deng, Hang; Wilson, Elizabeth J; Fitts, Jeffrey P; Peters, Catherine A

    2016-05-17

    We developed the Leakage Risk Monetization Model (LRiMM) which integrates simulation of CO2 leakage from geologic CO2 storage reservoirs with estimation of monetized leakage risk (MLR). Using geospatial data, LRiMM quantifies financial responsibility if leaked CO2 or brine interferes with subsurface resources, and estimates the MLR reduction achievable by remediating leaks. We demonstrate LRiMM with simulations of 30 years of injection into the Mt. Simon sandstone at two locations that differ primarily in their proximity to existing wells that could be leakage pathways. The peak MLR for the site nearest the leakage pathways ($7.5/tCO2) was 190x larger than for the farther injection site, illustrating how careful siting would minimize MLR in heavily used sedimentary basins. Our MLR projections are at least an order of magnitude below overall CO2 storage costs at well-sited locations, but some stakeholders may incur substantial costs. Reliable methods to detect and remediate leaks could further minimize MLR. For both sites, the risk of CO2 migrating to potable aquifers or reaching the atmosphere was negligible due to secondary trapping, whereby multiple impervious sedimentary layers trap CO2 that has leaked through the primary seal of the storage formation. PMID:27052112

  6. Understanding instrumental Stokes leakage in Murchison Widefield Array polarimetry

    NASA Astrophysics Data System (ADS)

    Sutinjo, A.; O'Sullivan, J.; Lenc, E.; Wayth, R. B.; Padhi, S.; Hall, P.; Tingay, S. J.

    2015-01-01

    This paper offers an electromagnetic, more specifically array theory, perspective on understanding strong instrumental polarization effects for planar low-frequency "aperture arrays" with the Murchison Widefield Array (MWA) as an example. A long-standing issue that has been seen here is significant instrumental Stokes leakage after calibration, particularly in Stokes Q at high frequencies. A simple model that accounts for interelement mutual coupling is presented which explains the prominence of Q leakage seen when the array is scanned away from zenith in the principal planes. On these planes, the model predicts current imbalance in the X (E-W) and Y (N-S) dipoles and hence the Q leakage. Although helpful in concept, we find that this model is inadequate to explain the full details of the observation data. This finding motivates further experimentation with more rigorous models that account for both mutual coupling and embedded element patterns. Two more rigorous models are discussed: the "full" and "average" embedded element patterns. The viability of the full model is demonstrated by simulating current MWA practice of using a Hertzian dipole model as a Jones matrix estimate. We find that these results replicate the observed Q leakage to approximately 2 to 5%. Finally, we offer more direct indication for the level of improvement expected from upgrading the Jones matrix estimate with more rigorous models. Using the average embedded pattern as an estimate for the full model, we find that Q leakage of a few percent is achievable.

  7. [Marginal leakage in composite resin restorations in posterior teeth. Effect of material, cavity preparation and enamel conditioning at the cervical level].

    PubMed

    Marotta Araujo, R; da Silva Filho, F P; Dias Mendes, A J

    1990-01-01

    The purpose of this "in vitro" study was to investigate the cervical marginal leakage in class II restorations with chemically cured resin (P10) and light-cured resin (P30) in two types of cavities: conventional and adhesive. The effect of acid-etching in this area was also observed. Dentine adhesive Scotchbond was used in all experimental groups. Leakage was evidenced by Rodamina B dye penetration after thermocycling procedure between 10 degrees C and 50 degrees C temperature and analysed by using Zeiss Stereoscopic Magnifying Glass (10 X). According to the results obtained marginal leakage occurred in all experimental groups, with lower percentage for adhesives cavities when enamel acid-etching and light-cured resin P30 was used.

  8. A quantitative methodology to assess the risks to human health from CO2 leakage into groundwater

    NASA Astrophysics Data System (ADS)

    Siirila, E.; Sitchler, A.; Maxwell, R. M.; McCray, J. E.

    2010-12-01

    Leakage of CO2 and associated gases into overlying aquifers as a result of geologic carbon capture and sequestration may have adverse impacts on aquifer drinking-water quality. Gas or aqueous-phase leakage may occur due to transport via faults and fractures, through faulty well bores, or through leaky confining materials. Contaminants of concern include aqueous salts and dissolved solids, gaseous or aqueous-phase organic contaminants, and acidic gas or aqueous-phase fluids that can liberate metals from aquifer minerals. Here we present a quantitative risk assessment framework to predict potential human health risk from CO2 leakage into drinking water aquifers. This framework incorporates the potential release of CO2 into the drinking water aquifer; mobilization of metals due to a decrease in pH; transport of these metals down gradient to municipal receptors; distributions of contaminated groundwater to multiple households; and exposure and health risk to individuals using this water for household purposes. Additionally, this framework is stochastic, incorporates detailed variations in geological and geostatistical parameters and discriminates between uncertain and variable parameters using a two-stage, or nested, Monte Carlo approach. This approach is demonstrated using example simulations with hypothetical, yet realistic, aquifer characteristics and leakage scenarios. These example simulations show a greater risk for arsenic than for lead for both cancer and non-cancer endpoints, an unexpected finding given greater toxicity of lead at lower doses than arsenic. It was also found that higher background groundwater gradients also yield higher risk. The overall risk and the associated uncertainty are sensitive to the extent of aquifer stratification and the degree of local-scale dispersion. These results all highlight the importance of hydrologic modeling in risk assessment. A linear relationship between carcinogenic and noncarcinogenic risk was found for arsenic and

  9. The Input Hypothesis: An Inside Look.

    ERIC Educational Resources Information Center

    Higgs, Theodore V.

    1985-01-01

    Summarizes and discusses Krashen's "input hypothesis" as presented in his "Principles and Practice in Second Language Acquisition." Suggests that the input hypothesis fails to account convincingly for arrested second language acquisition in an acquisition-rich environment and that it is not directly applicable to U.S. high school and university…

  10. A Model of the Relative Income Hypothesis

    ERIC Educational Resources Information Center

    Sanders, Shane

    2010-01-01

    James Duesenberry's (1949) relative income hypothesis holds substantial empirical credibility, as well as a rich set of implications. Although present in the pages of leading economics journals, the hypothesis has become all but foreign to the blackboards of economics classrooms. To help reintegrate the concept into the undergraduate economics…

  11. Ecosystem Succession and Nutrient Retention: A Hypothesis

    ERIC Educational Resources Information Center

    Vitousek, Peter M.; Reiners, William A.

    1975-01-01

    A hypothesis is presented for the regulation of elemental losses from terrestrial ecosystems. Losses of elements are controlled by the net increment of biomass growth and the elemental composition of this net increment. According to this hypothesis, loss rates are highest in early succession and in steady state ecosystems. (Author/EB)

  12. The Interaction Hypothesis: A Literature Review

    ERIC Educational Resources Information Center

    Tran, Thu Hoang

    2009-01-01

    This paper will examine the interaction hypothesis (IH) in second language acquisition (SLA). To begin with a short discussion of the confusing terms in SLA such as theory, model, hypothesis, and construct will be done so as to help readers easily understand theories in the field of SLA and related concepts. Next, what the IH is, and who proposed…

  13. Statistics and Hypothesis Testing in Biology.

    ERIC Educational Resources Information Center

    Maret, Timothy J.; Ziemba, Robert E.

    1997-01-01

    Suggests that early in their education students be taught to use basic statistical tests as rigorous methods of comparing experimental results with scientific hypotheses. Stresses that students learn how to use statistical tests in hypothesis-testing by applying them in actual hypothesis-testing situations. To illustrate, uses questions such as…

  14. Three Strategies for Elaborating the Cultivation Hypothesis.

    ERIC Educational Resources Information Center

    Potter, W. James

    1988-01-01

    Uses three strategies (dividing cultivation into component subprocesses, testing for an intervening variable, and contingent relationships) for elaborating the cultivation hypothesis. Finds evidence that cultivation effects do exist but that dividing the socialization process does not increase the predictive power of the cultivation hypothesis.…

  15. Current Status of the Molecular Clock Hypothesis

    ERIC Educational Resources Information Center

    Hermann, Gilbert

    2003-01-01

    Molecular genetics is a rapidly changing field with new developments almost from day to day. One interesting hypothesis that has come from everyone's ability to sequence proteins and/or genes is that of the molecular clock. This hypothesis postulates that homologous sequences of DNA and thus macro molecules evolve at a constant and invariable rate…

  16. Crack detection and leakage monitoring on reinforced concrete pipe

    NASA Astrophysics Data System (ADS)

    Feng, Qian; Kong, Qingzhao; Huo, Linsheng; Song, Gangbing

    2015-11-01

    Reinforced concrete underground pipelines are some of the most widely used types of structures in water transportation systems. Cracks and leakage are the leading causes of pipeline structural failures which directly results in economic losses and environmental hazards. In this paper, the authors propose a piezoceramic based active sensing approach to detect the cracks and the further leakage of concrete pipelines. Due to the piezoelectric properties, piezoceramic material can be utilized as both the actuator and the sensor in the active sensing approach. The piezoceramic patch, which is sandwiched between protective materials called ‘smart aggregates,’ can be safely embedded into concrete structures. Circumferential and axial cracks were investigated. A wavelet packet-based energy analysis was developed to distinguish the type of crack and determine the further leakage based on different stress wave energy attenuation propagated through the cracks.

  17. Identifying and Managing Gas Leakage from Subsurface Sources

    NASA Astrophysics Data System (ADS)

    Benson, S. M.

    2015-12-01

    Subsurface gas accumulations exist from both natural sources such as hydrocarbon reservoirs, as well as, man-made sources such as natural gas storage, gas pipelines, CO2 storage, or even H2 storage. Both natural and manmade sources of subsurface gases have the potential to leak to the surface. Leakage can cause safety hazards and detrimental impacts associated with the release of greenhouse gases into the atmosphere. Leak management, which involves identifying, characterizing, assessing, and remediating leakage requires a coordinated and systematic approach to effectively deal with these occurrences. Here an overall workflow for leak management is presented, along with technological options and challenges for successful implementation. Many tools and approaches for leak management are available and in use today. However, the increased attention to leakage from a larger variety of sources, particularly associated with legacy facilities and infrastructure, raises new issues and challenges that are highlighted here.

  18. An Investigation of Tendon Corrosion-Inhibitor Leakage into Concrete

    SciTech Connect

    Costello, J.F.; Naus, D.J.; Oland, C.B.

    1999-07-05

    During inspections performed at US nuclear power plants several years ago, some of the prestressed concrete containment had experienced leakage of the tendon sheathing filler. A study was conducted to indicate the extent of the leakage into the concrete and its potential effects on concrete properties. Concrete core samples were obtained from the Trojan Nuclear Plant. Examination and testing of the core samples indicated that the appearance of tendon sheathing filler on the surface was due to leakage of the filler from the conduits and its subsequent migration to the concrete surface through cracks that were present. Migration of the tendon sheathing filler was confined to the cracks with no perceptible movement into the concrete. Results of compressive strength tests indicated that the concrete quality was consistent in the containment and that the strength had increased relative to the strength at 28 days age.

  19. Leakage radiation microscope for observation of non-transparent samples.

    PubMed

    Merlo, Juan M; Ye, Fan; Burns, Michael J; Naughton, Michael J

    2014-09-22

    We describe a leakage radiation microscope technique that can be used to extend the leakage radiation microscopy to optically non-transparent samples. In particular, two experiments are presented, first to demonstrate that acquired images with our configuration correspond to the leakage radiation phenomenon and second, to show possible applications by directly imaging a plasmonic structure that previously could only be imaged with a near-field scanning optical microscope. It is shown that the measured surface plasmon wavelength and propagation length agree with theoretically-calculated values. This configuration opens the possibility to study important effects where samples are optically non-transparent, as in plasmonic cavities and single hole plasmonic excitation, without the use of time-consuming near-field scanning optical microscopy.

  20. Air Leakage of U.S. Homes: Model Prediction

    SciTech Connect

    Sherman, Max H.; McWilliams, Jennifer A.

    2007-01-01

    Air tightness is an important property of building envelopes. It is a key factor in determining infiltration and related wall-performance properties such as indoor air quality, maintainability and moisture balance. Air leakage in U.S. houses consumes roughly 1/3 of the HVAC energy but provides most of the ventilation used to control IAQ. The Lawrence Berkeley National Laboratory has been gathering residential air leakage data from many sources and now has a database of more than 100,000 raw measurements. This paper uses a model developed from that database in conjunction with US Census Bureau data for estimating air leakage as a function of location throughout the US.

  1. Albumin leakage in online hemodiafiltration, more convective transport, more losses?

    PubMed

    Vega, Almudena; Quiroga, Borja; Abad, Soraya; Aragoncillo, Inés; Arroyo, David; Panizo, Nayara; López-Gómez, Juan M

    2015-06-01

    Online hemodiafiltration (OL-HDF) has now demonstrated some benefits in reducing mortality. It seems that rising convective volumes improve the outcomes, but the risks of it, such as albumin leakage, are not well defined yet. The aim of the present study was to evaluate the albumin leakage using two different filters with 20 and 30 L of post-dilution OL-HDF. In this cross-sectional study, 20 prevalent patients receiving post-dilution OL-HDL were included. We analyzed two dialyzers: FX1000, FMC and Polyflux 210H, Gambro. During four consecutive dialysis sessions, monitors were programmed using control-volume to obtain 20 or 30 L with both dialyzers. We collected albumin samples of the effluent at 5, 15, 30, 45 and 60 min and performed area under the curve (AUC) determinations for evaluating the losses. Mean patient age was 60 ± 9 years, and 70% were men. Albumin leakage was significant higher with Polyflux 210H when compared to FX 1000 FMC. A convective volume of 30 L produced greater albumin leakage than 20 L with both filters, though only with the FX 1000 FMC was it significant (minimum albumin leakage during first hour with FX 1000 FMC 20 L: 79.2 [0.0-175.7] mg; 30 liters: 403.3 [63.5-960.7] mg; with PF 210 Gambro 20 L: 869.1 [420.0-3214.7] mg; 30 L: 1841.7 [443.8-3417.5] mg). During OL-HDF, convective transport causes albumin leakage at least during the first hour. The albumin concentration in the effluent differs according to the type of filter used and the convective volume.

  2. Measuring Agulhas Current strength and leakage from satellite altimetry

    NASA Astrophysics Data System (ADS)

    Le Bars, Dewi; De Ruijter, Wilhelmus P. M.; Dijkstra, Henk A.

    2013-04-01

    The Agulhas leakage is a flux of relatively warm and salty water from the Indian Ocean to the South Atlantic Ocean. It occurs south of the African continent where the Agulhas Current retroflects and sheds large anticyclonic eddies that quickly break up and mix with the surrounding water. This is one of the most energetic regions of the world ocean and the Agulhas leakage is therefore very difficult to quantify. In recent years two independent studies (Biastoch et al. 2009, Rouault et al. 2009) using different ocean models pointed out the possibility that the strength of the Agulhas leakage could have increased over the last decades. Unfortunately several discrepancies exist between these two studies on the magnitude and the causes of this increase showing the limitations of numerical modelling in this area. In this work we use a combination of along-track and mapped satellite geostrophic velocities to compute the strength of the Agulhas Current and to follow Lagrangian particles released in its core. The results confirm a positive trend of the volume of Agulhas leakage over the last two decades. This allows us to investigate the dependence of the leakage to upstream conditions like the Agulhas Current transport, the pattern and strength of the westerly winds and to test previous theories on the relations between these factors. Biastoch, A., Böning, C. W., Schwarzkopf, F. U. and Lutjeharms, J. R. E.: Increase in Agulhas leakage due to poleward shift of Southern Hemisphere westerlies, Nature, 462(7272), 495-498, doi:10.1038/nature08519, 2009. Rouault, M., Penven, P. and Pohl, B.: Warming in the Agulhas Current system since the 1980's, Geophys. Res. Lett, 36(L12602), doi:10.1029/2009GL037987, 2009.

  3. Antifreeze glycoproteins inhibit leakage from liposomes during thermotropic phase transitions.

    PubMed Central

    Hays, L M; Feeney, R E; Crowe, L M; Crowe, J H; Oliver, A E

    1996-01-01

    Antifreeze glycoproteins (AFGPs), found in the blood of polar fish at concentrations as high as 35 g/liter, are known to prevent ice crystal growth and depress the freezing temperature of the blood. Previously, Rubinsky et al. [Rubinsky, B., Mattioli, M., Arav, A., Barboni, B. & Fletcher, G. L. (1992) Am. J. Physiol. 262, R542-R545] provided evidence that AFGPs block ion fluxes across membranes during cooling, an effect that they ascribed to interactions with ion channels. We investigated the effects of AFGPs on the leakage of a trapped marker from liposomes during chilling. As these liposomes are cooled through the transition temperature, they leak approximately 50% of their contents. Addition of less than 1 mg/ml of AFGP prevents up to 100% of this leakage, both during chilling and warming through the phase transition. This is a general effect that we show here applies to liposomes composed of phospholipids with transition temperatures ranging from 12 degrees C to 41 degrees C. Because these results were obtained with liposomes composed of phospholipids alone, we conclude that the stabilizing effects of AFGPs on intact cells during chilling reported by Rubinsky et al. may be due to a nonspecific effect on the lipid components of native membranes. There are other proteins that prevent leakage, but only under specialized conditions. For instance, antifreeze proteins, bovine serum albumin, and ovomucoid all either have no effect or actually induce leakage. Following precipitation with acetone, all three proteins inhibited leakage, although not to the extent seen with AFGPs. Alternatively, there are proteins such as ovotransferrin that have no effect on leakage, either before or after acetone precipitation. PMID:8692905

  4. Semianalytical solution for CO2 leakage through an abandoned well.

    PubMed

    Nordbotten, Jan Martin; Celia, Michael A; Bachu, Stefan; Dahle, Helge K

    2005-01-15

    Capture and subsequent injection of carbon dioxide into deep geological formations is being considered as a means to reduce anthropogenic emissions of CO2 to the atmosphere. If such a strategy is to be successful, the injected CO2 must remain within the injection formation for long periods of time, at least several hundred years. Because mature continental sedimentary basins have a century-long history of oil and gas exploration and production, they are characterized by large numbers of existing oil and gas wells. For example, more than 1 million such wells have been drilled in the state of Texas in the United States. These existing wells represent potential leakage pathways for injected CO2. To analyze leakage potential, modeling tools are needed that predict leakage rates and patterns in systems with injection and potentially leaky wells. A new semianalytical solution framework allows simple and efficient prediction of leakage rates for the case of injection of supercritical CO2 into a brine-saturated deep aquifer. The solution predicts the extent of the injected CO2 plume, provides leakage rates through an abandoned well located at an arbitrary distance from the injection well, and estimates the CO2 plume extent in the overlying aquifer into which the fluid leaks. Comparison to results from a numerical multiphase flow simulator show excellent agreement. Example calculations show the importance of outer boundary conditions, the influence of both density and viscosity contrasts in the resulting solutions, and the potential importance of local upconing around the leaky well. While several important limiting assumptions are required, the new semianalytical solution provides a simple and efficient procedure for estimation of CO2 leakage for problems involving one injection well, one leaky well, and multiple aquifers separated by impermeable aquitards. PMID:15707061

  5. Is intervertebral cement leakage a risk factor for new adjacent vertebral collapse?

    PubMed

    Churojana, Anchalee; Songsaeng, Dittapong; Khumtong, Rujimas; Suwanbundit, Anek; Saliou, Guillaume

    2014-10-31

    This retrospective study evaluated the relationship between intervertebral cement leakage and new adjacent vertebral fracture and describes the different characteristics of cement leakage. Increased risk of new adjacent vertebral fracture (NF) has been reported to be a complication of cement leakage in vertebroplasty. In our observation, an incidental intervertebral cement leakage may occur during vertebroplasty but is commonly asymptomatic. The study focused on osteoporotic collapse patients who had percutaneous vertebroplasty (PV) between 2005 and 2007. We divided patients into leakage and non-leakage groups and compared the incidence of NF. Leakage characteristics were divided into three types: Type I intervertebral-extradiscal leakage, Type II intradiscal leakage and Type III combined leakage. Visual analog scale for pain and the Karnofsky Performance Status at 24 h, three months, six months and one year were compared between groups and types of leakages. Among 148 PVs (102 patients) there were 30 leakages (20.27%) and 21(14.19%) NFs. The incidence of NF did not significantly differ between leakage and non-leakage groups (P<0.05). Type II was the most common type of leakage (15/30). Reduction of average pain and improvement of Karnofsky Performance Status score did not differ between groups (P< 0.05). Type II had decreased pain score < type I and III at 24 h (P < 0.01), three months and six months (P < 0.1) but not at one year (P<0.10). Type II also had decreased pain score < non-leakage group only at 24 h (P<0.05). Intervertebral cement leakage is not an increased risk for NF, influenced outcomes of pain relief or improvement of physical function. Intradiscal leakage (Type II) is the most common characteristic of cement leakage and probably related to delayed pain relief.

  6. Measured effect of step axial location on labyrinth seal leakage

    NASA Technical Reports Server (NTRS)

    Morrison, G. L.; Rhode, D. L.

    1992-01-01

    An advanced, finite volume code has been extensively used in a parametric design study of simple stepped seals, in order to ascertain a leakage-minimizing optimal design and test it, in conjunction with the baseline case of the wear-ring seal of a high pressure pump. It is found that a significant leakage effect arises from this shifting of the rotor and stator sealing surfaces; at extremely low rpm, a significant shaft speed effect occurs for the optimized design in some shaft locations.

  7. Atlantic multi-decadal oscillation covaries with Agulhas leakage

    DOE PAGES

    Biastoch, Arne; Durgadoo, Jonathan V.; Morrison, Adele K.; van Sebille, Erik; Weijer, Wilbert; Griffies, Stephen M.

    2015-12-10

    The interoceanic transfer of seawater between the Indian Ocean and the Atlantic, ‘Agulhas leakage’, forms a choke point for the overturning circulation in the global ocean. Here, by combining output from a series of high-resolution ocean and climate models with in situ and satellite observations, we construct a time series of Agulhas leakage for the period 1870–2014. The time series demonstrates the impact of Southern Hemisphere westerlies on decadal timescales. Agulhas leakage shows a correlation with the Atlantic Multi-decadal Oscillation on multi-decadal timescales; the former leading by 15 years. Lastly, this is relevant for climate in the North Atlantic.

  8. Microvascular leakage of plasma proteins after PUVA and UVA

    SciTech Connect

    Staberg, B.; Worm, A.M.; Rossing, N.; Brodthagen, H.

    1982-04-01

    The transcapillary escape rate of albumin (TERalb), is a parameter of the leakage of macromolecules from the total microvasculature. In patients with psoriasis short-term PUVA treatment induces an increase in TERalb. In this study TERalb was measured in 3 groups of normal humans treated with PUVA, UVA and 8-methoxypsoralen. Treatment with PUVA and UVA caused a statistically significant increase in TERalb, whereas treatment with 8-methoxypsoralen did not induce any measurable changes. It is concluded that the UVA irradiation causes the abnormal leakage of macromolecules, whereas psoralen is not the responsible component. Furthermore the phenomenon can be elicited in normals and is not based on a preexisting psoriasis.

  9. Leakage neutron radiation in a medical electron accelerator

    NASA Astrophysics Data System (ADS)

    Paredes, Lydia; Balcazar, Miguel; Genis, Roberto; Ortiz, Raúl

    2001-10-01

    A simple method was used for the calculation of neutron yield produced by main components of medical electron accelerator head, using a simplified geometric model with spherical-shell for the head shielding made of different materials. The leakage neutron radiation on the patient plane and outside the patient plane at one meter from the x-ray target for a Varian accelerator model Clinac 2100C was evaluated experimentally, using Panasonic UD-802 and UD-809 thermoluminescent dosimeters and CR-39 nuclear track dosimeters. The measured values of leakage neutron radiation were lower than the limits specified in the NCRP-102 and IEC 60601-2-1-Ed.2.0 reports.

  10. The arsenic exposure hypothesis for Alzheimer disease.

    PubMed

    Gong, Gordon; OʼBryant, Sid E

    2010-01-01

    Prior research has shown that arsenic exposure induces changes that coincide with most of the developmental, biochemical, pathologic, and clinical features of Alzheimer disease (AD) and associated disorders. On the basis of this literature, we propose the Arsenic Exposure Hypothesis for AD that is inclusive of and cooperative with the existing hypotheses. Arsenic toxicity induces hyperphosphorylation of protein tau and overtranscription of the amyloid precursor protein, which are involved in the formation of neurofibrillary tangles and brain amyloid plaques, consistent with the amyloid hypothesis of AD. Arsenic exposure has been associated with cardiovascular diseases and associated risk factors, which is in agreement with the vascular hypothesis of AD. Arsenic exposure invokes brain inflammatory responses, which resonates with the inflammatory hypotheses of AD. Arsenic exposure has been linked to reduced memory and intellectual abilities in children and adolescents, which provides a biologic basis for the developmental origin of health and disease hypothesis for AD. Arsenic and its metabolites generate free radicals causing oxidative stress and neuronal death, which fits the existing oxidative stress hypothesis. Taken together, the arsenic exposure hypothesis for AD provides a parsimonious testable hypothesis for the development and progression of this devastating disease at least for some subsets of individuals.

  11. Knowledge dimensions in hypothesis test problems

    NASA Astrophysics Data System (ADS)

    Krishnan, Saras; Idris, Noraini

    2012-05-01

    The reformation in statistics education over the past two decades has predominantly shifted the focus of statistical teaching and learning from procedural understanding to conceptual understanding. The emphasis of procedural understanding is on the formulas and calculation procedures. Meanwhile, conceptual understanding emphasizes students knowing why they are using a particular formula or executing a specific procedure. In addition, the Revised Bloom's Taxonomy offers a twodimensional framework to describe learning objectives comprising of the six revised cognition levels of original Bloom's taxonomy and four knowledge dimensions. Depending on the level of complexities, the four knowledge dimensions essentially distinguish basic understanding from the more connected understanding. This study identifiesthe factual, procedural and conceptual knowledgedimensions in hypothesis test problems. Hypothesis test being an important tool in making inferences about a population from sample informationis taught in many introductory statistics courses. However, researchers find that students in these courses still have difficulty in understanding the underlying concepts of hypothesis test. Past studies also show that even though students can perform the hypothesis testing procedure, they may not understand the rationale of executing these steps or know how to apply them in novel contexts. Besides knowing the procedural steps in conducting a hypothesis test, students must have fundamental statistical knowledge and deep understanding of the underlying inferential concepts such as sampling distribution and central limit theorem. By identifying the knowledge dimensions of hypothesis test problems in this study, suitable instructional and assessment strategies can be developed in future to enhance students' learning of hypothesis test as a valuable inferential tool.

  12. Hypothesis-free? No such thing

    SciTech Connect

    Wiley, H. S.

    2008-06-01

    Finding meaningful relationships in complex datasets requires starting with the appropriate data. A hypothesis usually takes the form of a mechanistic relationship between a specific cause and a consequent effect, and this will almost always depend on experimental context. There are some circumstances when data must be gathered in the absence of context or hypothesis to characterize a system, but it is unrealistic to expect such preliminary studies to lead to significant biological insights. For this, you need a hypothesis. Systems biology might be the future of biology, but we still need hypotheses to take us where we want to go.

  13. 49 CFR 178.346-5 - Pressure and leakage tests.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... CFR 63.425(e). To satisfy the leakage test requirements of this paragraph, the test specified in 40 CFR 63.425(e)(1) must be conducted using air. The hydrostatic test alternative permitted under Appendix A to 40 CFR Part 60 (“Method 27—Determination of Vapor Tightness of Gasoline Delivery Tank...

  14. Detectivity of gas leakage based on electromagnetic radiation transfer

    NASA Astrophysics Data System (ADS)

    Long, Yunting; Wang, Lingxue; Li, Jiakun; Zhang, Changxing; Zhang, Bei

    2011-05-01

    Standoff detection of gas leakage is a fundamental need in petrochemical and power industries. The passive gas imaging system using thermal imager has been proven to be efficient to visualize leaking gas which is not visible to the naked eye. The detection probability of gas leakage is the basis for designing a gas imaging system. Supposing the performance parameters of the thermal imager are known, the detectivity based on electromagnetic radiation transfer model to image gas leakage is analyzed. This model takes into consideration a physical analysis of the gas plume spread in the atmosphere-the interaction processes between the gas and its surrounding environment, the temperature of the gas and the background, the background surface emissivity, and also gas concentration, etc. Under a certain environmental conditions, through calculating the radiation reaching to the detector from the camera's optical field of view, we obtain an entity "Gas Equivalent Blackbody Temperature Difference (GEBTD)" which is the radiation difference between the on-plume and off-plume regions. Comparing the GEBTD with the Noise Equivalent Temperature Difference (NETD) of the thermal imager, we can know whether the system can image the gas leakage. At last, an example of detecting CO2 gas by JADE MWIR thermal imager with a narrow band-pass filter is presented.

  15. Exploitation of Unintentional Information Leakage from Integrated Circuits

    ERIC Educational Resources Information Center

    Cobb, William E.

    2011-01-01

    The information leakage of electronic devices, especially those used in cryptographic or other vital applications, represents a serious practical threat to secure systems. While physical implementation attacks have evolved rapidly over the last decade, relatively little work has been done to allow system designers to effectively counter the…

  16. 75 FR 20546 - Total Inward Leakage Requirements for Respirators

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-04-20

    ...: Centers for Disease Control and Prevention, Department of Health and Human Services. ACTION: Notice of proposed rulemaking; reopening of comment period. SUMMARY: The Centers for Disease Control and Prevention... for Occupational Safety and Health (NIOSH) of CDC, entitled ``Total Inward Leakage Requirements...

  17. 75 FR 29699 - Total Inward Leakage Requirements for Respirators

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-05-27

    ... HUMAN SERVICES Centers for Disease Control and Prevention 42 CFR Part 84 RIN 0920-AA33 Total Inward Leakage Requirements for Respirators AGENCY: The National Institute for Occupational Safety and Health (NIOSH) of the Centers for Disease Control and Prevention (CDC), Department of Health and Human...

  18. Leakage Currents and Gas Generation in Advanced Wet Tantalum Capacitors

    NASA Technical Reports Server (NTRS)

    Teverovsky, Alexander

    2015-01-01

    Currently, military grade, established reliability wet tantalum capacitors are among the most reliable parts used for space applications. This has been achieved over the years by extensive testing and improvements in design and materials. However, a rapid insertion of new types of advanced, high volumetric efficiency capacitors in space systems without proper testing and analysis of degradation mechanisms might increase risks of failures. The specifics of leakage currents in wet electrolytic capacitors is that the conduction process is associated with electrolysis of electrolyte and gas generation resulting in building up of internal gas pressure in the parts. The risk associated with excessive leakage currents and increased pressure is greater for high value advanced wet tantalum capacitors, but it has not been properly evaluated yet. In this work, in Part I, leakages currents in various types of tantalum capacitors have been analyzed in a wide range of voltages, temperatures, and time under bias. Gas generation and the level of internal pressure have been calculated in Part II for different case sizes and different hermeticity leak rates to assess maximal allowable leakage currents. Effects related to electrolyte penetration to the glass seal area have been studied and the possibility of failures analyzed in Part III. Recommendations for screening and qualification to reduce risks of failures have been suggested.

  19. Complications in Percutaneous Vertebroplasty Associated with Puncture or Cement Leakage

    SciTech Connect

    Baumann, Clemens Fuchs, Heiko; Kiwit, Juergen; Westphalen, Kerstin; Hierholzer, Johannes

    2007-04-15

    Due to the minimally invasive character and excellent clinical outcome of percutaneous vertebroplasty (PVP), the procedure is being performed in greatly increasing numbers. While PVP has a low complication rate in general, severe complications can occur. We focus on the imaging appearance of complications of PVP associated with puncture or cement leakage-from harmless to life-threatening.

  20. Leakage of fluid in different types of tracheal tubes.

    PubMed

    Winklmaier, U; Wüst, K; Schiller, S; Wallner, F

    2006-10-01

    The aim of this study was to evaluate leakage of liquids, i.e., water and saliva, past low-pressure cuffs of tracheostomy tubes. Three different types of tracheostomy tubes, TRACOE vario (TRACOE Medical GmbH, Germany), Rüsch Ultra-Tracheoflex (Rüsch GmbH, Germany), and Portex Blue Line Ultra (Smiths Medical, UK) were tested in isolated pig tracheas. Sixty samples (10 tubes each of 7- and 8-mm inner diameter of each type) were used. Four different experiments were devised: type 1 (water and artificial ventilation), type 2 (water and no artificial ventilation), type 3 (saliva and artificial ventilation), and type 4 (saliva and no artificial ventilation). Six milliliters of water or artificial saliva were infused over the cuff and the volume of fluid that leaked past the cuff was measured after 5, 10, and 15 min. Intracuff pressure was also measured three times. The saliva experiments resulted in less leakage than the water experiments. Leakage after treatment with water or artificial saliva is higher without artificial ventilation than with ventilation. The amount of leakage among the tubes with respect to manufacturer showed statistically significant results. However, there were no differences among tracheostomy tubes with respect to internal diameter.

  1. Visual Inspection of Water Leakage from Ground Penetrating Radar Radargram

    NASA Astrophysics Data System (ADS)

    Halimshah, N. N.; Yusup, A.; Mat Amin, Z.; Ghazalli, M. D.

    2015-10-01

    Water loss in town and suburban is currently a significant issue which reflect the performance of water supply management in Malaysia. Consequently, water supply distribution system has to be maintained in order to prevent shortage of water supply in an area. Various techniques for detecting a mains water leaks are available but mostly are time-consuming, disruptive and expensive. In this paper, the potential of Ground Penetrating Radar (GPR) as a non-destructive method to correctly and efficiently detect mains water leaks has been examined. Several experiments were designed and conducted to prove that GPR can be used as tool for water leakage detection. These include instrument validation test and soil compaction test to clarify the maximum dry density (MDD) of soil and simulation studies on water leakage at a test bed consisting of PVC pipe burying in sand to a depth of 40 cm. Data from GPR detection are processed using the Reflex 2D software. Identification of water leakage was visually inspected from the anomalies in the radargram based on GPR reflection coefficients. The results have ascertained the capability and effectiveness of the GPR in detecting water leakage which could help avoiding difficulties with other leak detection methods.

  2. THE CARBON DIOXIDE LEAKAGE FROM CHAMBERS MEASURED USING SULFUR HEXAFLUORIDE

    EPA Science Inventory

    In plant chamber studies, if Co2 leaking from a chamber is not quantified, it can lead to an overestimate of assimilation rates and an underestimate of respiration rates: consequently, it is critical that Co2 leakage be determined. Sulfur Hexafluoride (SF6) was introduced into t...

  3. Blower-door techniques for measuring interzonal leakage

    SciTech Connect

    Hult, Erin L.; Sherman, Max H.; Walker, Iain

    2013-01-01

    Abstract The standard blower door test methods, such as ASTM E779, describe how to use a single blower door to determine the total leakage of a single-zone structure such as a detached single-family home. There are no standard test methods for measuring interzonal leakage in a two-zone or multi-zone building envelope such as might be encountered in with an attached garage or in a multifamily building. Some practitioners have been using techniques that involve making multiple measurements with a single blower door as well as combined measurements using multiple blower doors. Even for just two zones there are dozens of combinations of one-door and two-door test protocols that could conceivably be used to determine the interzonal air tightness. We examined many of these two-zone configurations using both simulation and measured data to estimate the accuracy and precision of each technique for realistic measurement scenarios. We also considered the impact of taking measurements at a single pressure versus over multiple pressures. We compared the various techniques and evaluated them for specific uses. Some techniques work better in one leakage regime; some are more sensitive to wind and other noise; some are more suited to determining only a subset of the leakage values. This paper makes recommendations on which techniques to use or not use for various cases and provides data that could be used to develop future test methods.

  4. Osmotic Stressing, Membrane Leakage, and Fluorescence: An Introductory Biochemistry Demonstration

    ERIC Educational Resources Information Center

    Seu, Kalani J.

    2015-01-01

    A fluorescence demonstration is described that incorporates several fundamental aspects of an introductory biochemistry course. A variation of a known leakage assay is utilized to prepare vesicles containing a quenched fluorophore. The vesicles are exposed to several osmotic environments ranging from isotonic to hypotonic. The degree of vesicle…

  5. Modeling sewage leakage to surrounding groundwater and stormwater drains.

    PubMed

    Ly, Duy Khiem; Chui, Ting Fong May

    2012-01-01

    Underground sewage pipe systems deteriorate over time resulting in cracks and joint defects. Sewage thus leaks out and contaminates the surrounding groundwater and the surface water in stormwater drains. Many studies have investigated the problem of sewage leakage but no published studies, to the best knowledge of the authors, have examined the hydrologic interactions between leaky sewage pipes, groundwater and stormwater drains. This study numerically models such interactions using generic conditions in Singapore. It first develops accurate representations of weep holes and leaky sewage pipes, and further shows the long-term and short-term system responses to rainfall events. Some of the implications include: (1) quality of water seeping into the drains tends to be low in dry years; (2) complete contaminant attenuation after pipe rehabilitation takes several years; (3) responses to rainfall events at weep holes are immediate but the effects on sewage leakage might only show up a few days later. The simulation results allow us to better understand the local-scale migration of sewage leakage from a sewage pipe to nearby stormwater drains. With calibrations and verifications with local field data, the modeling framework would be applicable and beneficial to the sewage leakage monitoring and sewage pipe rehabilitation worldwide.

  6. Plutonium Finishing Plant assessment of confinement system bypass leakage

    SciTech Connect

    Dick, J.D.

    1996-09-30

    The purpose of this report is to document walk-through`s of the safety class confinement systems at the Plutonium Finishing Plant (PFP). In addition this document outlines the actions taken to assess the confinement system for bypass leakage as well as establishing disposition for discovered deficiencies at the PFP.

  7. Vented piston seal prevents fluid leakage between two chambers

    NASA Technical Reports Server (NTRS)

    Mac Glashan, W. F.; Morrison, R.

    1964-01-01

    To prevent fluid leakage around piston seals separating two fluids under differential pressure, a venting system has been devised. Two methods may be used for venting seals through internal passages to an external low-pressure area, O-ring or split-ring seals.

  8. Can paternal leakage maintain sexually antagonistic polymorphism in the cytoplasm?

    PubMed Central

    Kuijper, B; Lane, N; Pomiankowski, A

    2015-01-01

    A growing number of studies in multicellular organisms highlight low or moderate frequencies of paternal transmission of cytoplasmic organelles, including both mitochondria and chloroplasts. It is well established that strict maternal inheritance is selectively blind to cytoplasmic elements that are deleterious to males – ’mother's curse’. But it is not known how sensitive this conclusion is to slight levels of paternal cytoplasmic leakage. We assess the scope for polymorphism when individuals bear multiple cytoplasmic alleles in the presence of paternal leakage, bottlenecks and recurrent mutation. When fitness interactions among cytoplasmic elements within an individual are additive, we find that sexually antagonistic polymorphism is restricted to cases of strong selection on males. However, when fitness interactions among cytoplasmic elements are nonlinear, much more extensive polymorphism can be supported in the cytoplasm. In particular, mitochondrial mutants that have strong beneficial fitness effects in males and weak deleterious fitness effects in females when rare (i.e. ’reverse dominance’) are strongly favoured under paternal leakage. We discuss how such epistasis could arise through preferential segregation of mitochondria in sex-specific somatic tissues. Our analysis shows how paternal leakage can dampen the evolution of deleterious male effects associated with predominant maternal inheritance of cytoplasm, potentially explaining why ’mother's curse’ is less pervasive than predicted by earlier work. PMID:25653025

  9. Killing Me Softly: The Fetal Origins Hypothesis*

    PubMed Central

    Almond, Douglas

    2013-01-01

    In the epidemiological literature, the fetal origins hypothesis associated with David J. Barker posits that chronic, degenerative conditions of adult health, including heart disease and type 2 diabetes, may be triggered by circumstance decades earlier, in utero nutrition in particular. Economists have expanded on this hypothesis, investigating a broader range of fetal shocks and circumstances and have found a wealth of later-life impacts on outcomes including test scores, educational attainment, and income, along with health. In the process, they have provided some of the most credible observational evidence in support of the hypothesis. The magnitude of the impacts is generally large. Thus, the fetal origins hypothesis has not only survived contact with economics, but has flourished. PMID:25152565

  10. Putting Down the Discovery Learning Hypothesis

    ERIC Educational Resources Information Center

    Chambers, David W.

    1971-01-01

    The author analyzes some of the conceptual problems which have prevented a direct test of the discovery learning hypothesis, provides an operational definition of discovery learning, and proposes an improved experimental paradigm. Appended are 38 references. (AA)

  11. Complement Propriety and Conspiracy in Nanomedicine: Perspective and a Hypothesis.

    PubMed

    Moghimi, Seyed Moein

    2016-04-01

    The complement system is the first line of body's defense against intruders and it acts as a functional bridge between innate and adaptive arms of the immune system. This commentary examines the key roles of complement activation in response to nanomedicine administration, including nucleic acid complexes. These comprise beneficial (eg, adjuvanticity) as well as adverse effects (eg, infusion-related reactions). Pigs (and sheep) are often used as predictive models of nanomedicine-mediated infusion-related reactions in humans. The validity of these models in relation to human responses is questioned, and an alternative hypothesis is presented. PMID:26720796

  12. Radiation leakage dose from Elekta electron collimation system.

    PubMed

    Pitcher, Garrett M; Hogstrom, Kenneth R; Carver, Robert L

    2016-09-08

    This study provided baseline data required for a greater project, whose objective was to design a new Elekta electron collimation system having significantly lighter electron applicators with equally low out-of field leakage dose. Specifically, off-axis dose profiles for the electron collimation system of our uniquely configured Elekta Infinity accelerator with the MLCi2 treatment head were measured and calculated for two primary purposes: 1) to evaluate and document the out-of-field leakage dose in the patient plane and 2) to validate the dose distributions calculated using a BEAMnrc Monte Carlo (MC) model for out-of-field dose profiles. Off-axis dose profiles were measured in a water phantom at 100 cm SSD for 1 and 2 cm depths along the in-plane, cross-plane, and both diagonal axes using a cylindrical ionization chamber with the 10 × 10 and 20 × 20 cm2 applicators and 7, 13, and 20 MeV beams. Dose distributions were calculated using a previously developed BEAMnrc MC model of the Elekta Infinity accelerator for the same beam energies and applicator sizes and compared with measurements. Measured results showed that the in-field beam flatness met our acceptance criteria (± 3% on major and ±4% on diagonal axes) and that out-of-field mean and maximum percent leakage doses in the patient plane met acceptance criteria as specified by the International Electrotechnical Commission (IEC). Cross-plane out-of-field dose profiles showed greater leakage dose than in-plane profiles, attributed to the curved edges of the upper X-ray jaws and multileaf collimator. Mean leakage doses increased with beam energy, being 0.93% and 0.85% of maximum central axis dose for the 10 × 10 and 20 × 20 cm2 applicators, respectively, at 20 MeV. MC calculations predicted the measured dose to within 0.1% in most profiles outside the radiation field; however, excluding model-ing of nontrimmer applicator components led to calculations exceeding measured data by as much as 0.2% for some regions

  13. Radiation leakage dose from Elekta electron collimation system.

    PubMed

    Pitcher, Garrett M; Hogstrom, Kenneth R; Carver, Robert L

    2016-01-01

    This study provided baseline data required for a greater project, whose objective was to design a new Elekta electron collimation system having significantly lighter electron applicators with equally low out-of field leakage dose. Specifically, off-axis dose profiles for the electron collimation system of our uniquely configured Elekta Infinity accelerator with the MLCi2 treatment head were measured and calculated for two primary purposes: 1) to evaluate and document the out-of-field leakage dose in the patient plane and 2) to validate the dose distributions calculated using a BEAMnrc Monte Carlo (MC) model for out-of-field dose profiles. Off-axis dose profiles were measured in a water phantom at 100 cm SSD for 1 and 2 cm depths along the in-plane, cross-plane, and both diagonal axes using a cylindrical ionization chamber with the 10 × 10 and 20 × 20 cm2 applicators and 7, 13, and 20 MeV beams. Dose distributions were calculated using a previously developed BEAMnrc MC model of the Elekta Infinity accelerator for the same beam energies and applicator sizes and compared with measurements. Measured results showed that the in-field beam flatness met our acceptance criteria (± 3% on major and ±4% on diagonal axes) and that out-of-field mean and maximum percent leakage doses in the patient plane met acceptance criteria as specified by the International Electrotechnical Commission (IEC). Cross-plane out-of-field dose profiles showed greater leakage dose than in-plane profiles, attributed to the curved edges of the upper X-ray jaws and multileaf collimator. Mean leakage doses increased with beam energy, being 0.93% and 0.85% of maximum central axis dose for the 10 × 10 and 20 × 20 cm2 applicators, respectively, at 20 MeV. MC calculations predicted the measured dose to within 0.1% in most profiles outside the radiation field; however, excluding model-ing of nontrimmer applicator components led to calculations exceeding measured data by as much as 0.2% for some regions

  14. Altered Phase Behavior in Membranes of Aging Dry Pollen May Cause Imbibitional Leakage.

    PubMed Central

    Van Bilsen, DGJL.; Hoekstra, F. A.; Crowe, L. M.; Crowe, J. H.

    1994-01-01

    Aging of dry pollen has been shown to coincide with increases of free fatty acids and lysophospholipids. These compounds reduce the integrity of hydrated liposomes made from isolated pollen phospholipids but do not lead to their total destruction. However, a massive, instantaneous leakage occurs upon imbibition of dry cattail pollen (Typha latifolia) that has aged to the point of complete loss of viability. To resolve the apparent discrepancy in stability between hydrated and dry membranes, the lyotropic phase behavior of two liposome systems containing lysophospholipid (12 mol%) was studied with differential scanning calorimetry and Fourier transform infrared spectroscopy. In both systems dehydration caused phase separation of the lipids. Fourier transform infrared data concerning phase behavior of isolated membranes from aging pollen and of membranes in situ did not show phase separations, probably because the assay technique was not sufficiently sensitive to detect them. However, aging of the pollen resulted in a permanent increase in the gel-to-liquid crystalline phase transition temperature (Tm) of isolated membranes and in a broadening of the transition in situ. We conclude that the increase in Tm of hydrated membranes may be more closely related to the leakage. PMID:12232157

  15. Leakage of Experimental Information to Potential Future Subjects by Debriefed Subjects

    ERIC Educational Resources Information Center

    Diener, Edward; And Others

    1972-01-01

    Leakage of experimental information from debreifed subjects into a university subject pool was studied. It was concluded that in settings similar to those of the experiment, leakage of information is not a serious problem. (Authors)

  16. Does the dopamine hypothesis explain schizophrenia?

    PubMed

    Lau, Chi-Ieong; Wang, Han-Cheng; Hsu, Jung-Lung; Liu, Mu-En

    2013-01-01

    The dopamine hypothesis has been the cornerstone in the research and clinical practice of schizophrenia. With the initial emphasis on the role of excessive dopamine, the hypothesis has evolved to a concept of combining prefrontal hypodopaminergia and striatal hyperdopaminergia, and subsequently to the present aberrant salience hypothesis. This article provides a brief overview of the development and evidence of the dopamine hypothesis. It will argue that the current model of aberrant salience explains psychosis in schizophrenia and provides a plausible linkage between the pharmacological and cognitive aspects of the disease. Despite the privileged role of dopamine hypothesis in psychosis, its pathophysiological rather than etiological basis, its limitations in defining symptoms other than psychosis, as well as the evidence of other neurotransmitters such as glutamate and adenosine, prompt us to a wider perspective of the disease. Finally, dopamine does explain the pathophysiology of schizophrenia, but not necessarily the cause per se. Rather, dopamine acts as the common final pathway of a wide variety of predisposing factors, either environmental, genetic, or both, that lead to the disease. Other neurotransmitters, such as glutamate and adenosine, may also collaborate with dopamine to give rise to the entire picture of schizophrenia. PMID:23843581

  17. Multiple hypothesis tracking for the cyber domain

    NASA Astrophysics Data System (ADS)

    Schwoegler, Stefan; Blackman, Sam; Holsopple, Jared; Hirsch, Michael J.

    2011-09-01

    This paper discusses how methods used for conventional multiple hypothesis tracking (MHT) can be extended to domain-agnostic tracking of entities from non-kinematic constraints such as those imposed by cyber attacks in a potentially dense false alarm background. MHT is widely recognized as the premier method to avoid corrupting tracks with spurious data in the kinematic domain but it has not been extensively applied to other problem domains. The traditional approach is to tightly couple track maintenance (prediction, gating, filtering, probabilistic pruning, and target confirmation) with hypothesis management (clustering, incompatibility maintenance, hypothesis formation, and Nassociation pruning). However, by separating the domain specific track maintenance portion from the domain agnostic hypothesis management piece, we can begin to apply the wealth of knowledge gained from ground and air tracking solutions to the cyber (and other) domains. These realizations led to the creation of Raytheon's Multiple Hypothesis Extensible Tracking Architecture (MHETA). In this paper, we showcase MHETA for the cyber domain, plugging in a well established method, CUBRC's INFormation Engine for Real-time Decision making, (INFERD), for the association portion of the MHT. The result is a CyberMHT. We demonstrate the power of MHETA-INFERD using simulated data. Using metrics from both the tracking and cyber domains, we show that while no tracker is perfect, by applying MHETA-INFERD, advanced nonkinematic tracks can be captured in an automated way, perform better than non-MHT approaches, and decrease analyst response time to cyber threats.

  18. Pasture succession in the Neotropics: extending the nucleation hypothesis into a matrix discontinuity hypothesis.

    PubMed

    Peterson, Chris J; Dosch, Jerald J; Carson, Walter P

    2014-08-01

    The nucleation hypothesis appears to explain widespread patterns of succession in tropical pastures, specifically the tendency for isolated trees to promote woody species recruitment. Still, the nucleation hypothesis has usually been tested explicitly for only short durations and in some cases isolated trees fail to promote woody recruitment. Moreover, at times, nucleation occurs in other key habitat patches. Thus, we propose an extension, the matrix discontinuity hypothesis: woody colonization will occur in focal patches that function to mitigate the herbaceous vegetation effects, thus providing safe sites or regeneration niches. We tested predictions of the classical nucleation hypothesis, the matrix discontinuity hypothesis, and a distance from forest edge hypothesis, in five abandoned pastures in Costa Rica, across the first 11 years of succession. Our findings confirmed the matrix discontinuity hypothesis: specifically, rotting logs and steep slopes significantly enhanced woody colonization. Surprisingly, isolated trees did not consistently significantly enhance recruitment; only larger trees did so. Finally, woody recruitment consistently decreased with distance from forest. Our results as well as results from others suggest that the nucleation hypothesis needs to be broadened beyond its historical focus on isolated trees or patches; the matrix discontinuity hypothesis focuses attention on a suite of key patch types or microsites that promote woody species recruitment. We argue that any habitat discontinuities that ameliorate the inhibition by dense graminoid layers will be foci for recruitment. Such patches could easily be manipulated to speed the transition of pastures to closed canopy forests. PMID:24972697

  19. Pasture succession in the Neotropics: extending the nucleation hypothesis into a matrix discontinuity hypothesis.

    PubMed

    Peterson, Chris J; Dosch, Jerald J; Carson, Walter P

    2014-08-01

    The nucleation hypothesis appears to explain widespread patterns of succession in tropical pastures, specifically the tendency for isolated trees to promote woody species recruitment. Still, the nucleation hypothesis has usually been tested explicitly for only short durations and in some cases isolated trees fail to promote woody recruitment. Moreover, at times, nucleation occurs in other key habitat patches. Thus, we propose an extension, the matrix discontinuity hypothesis: woody colonization will occur in focal patches that function to mitigate the herbaceous vegetation effects, thus providing safe sites or regeneration niches. We tested predictions of the classical nucleation hypothesis, the matrix discontinuity hypothesis, and a distance from forest edge hypothesis, in five abandoned pastures in Costa Rica, across the first 11 years of succession. Our findings confirmed the matrix discontinuity hypothesis: specifically, rotting logs and steep slopes significantly enhanced woody colonization. Surprisingly, isolated trees did not consistently significantly enhance recruitment; only larger trees did so. Finally, woody recruitment consistently decreased with distance from forest. Our results as well as results from others suggest that the nucleation hypothesis needs to be broadened beyond its historical focus on isolated trees or patches; the matrix discontinuity hypothesis focuses attention on a suite of key patch types or microsites that promote woody species recruitment. We argue that any habitat discontinuities that ameliorate the inhibition by dense graminoid layers will be foci for recruitment. Such patches could easily be manipulated to speed the transition of pastures to closed canopy forests.

  20. 47 CFR 76.1706 - Signal leakage logs and repair records.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 47 Telecommunication 4 2010-10-01 2010-10-01 false Signal leakage logs and repair records. 76.1706... leakage logs and repair records. Cable operators shall maintain a log showing the date and location of... the probable cause of the leakage. The log shall be kept on file for a period of two years and...

  1. 49 CFR 176.710 - Care following leakage or sifting of radioactive materials.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 2 2010-10-01 2010-10-01 false Care following leakage or sifting of radioactive... CARRIAGE BY VESSEL Detailed Requirements for Radioactive Materials § 176.710 Care following leakage or... segregated from unnecessary contact with personnel. In case of obvious leakage, or if the inside...

  2. 47 CFR 76.611 - Cable television basic signal leakage performance criteria.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 47 Telecommunication 4 2013-10-01 2013-10-01 false Cable television basic signal leakage... television basic signal leakage performance criteria. (a) No cable television system shall commence or... one of the following cable television basic signal leakage performance criteria: (1) Prior to...

  3. 42 CFR 84.182 - Exhalation valve leakage test; minimum requirements.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 42 Public Health 1 2010-10-01 2010-10-01 false Exhalation valve leakage test; minimum requirements...-Powered Air-Purifying Particulate Respirators § 84.182 Exhalation valve leakage test; minimum requirements... height while in a normal operating position. (b) Leakage between the valve and valve seat shall...

  4. 42 CFR 84.182 - Exhalation valve leakage test; minimum requirements.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 42 Public Health 1 2012-10-01 2012-10-01 false Exhalation valve leakage test; minimum requirements...-Powered Air-Purifying Particulate Respirators § 84.182 Exhalation valve leakage test; minimum requirements... height while in a normal operating position. (b) Leakage between the valve and valve seat shall...

  5. 42 CFR 84.204 - Exhalation valve leakage test; minimum requirements.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 42 Public Health 1 2010-10-01 2010-10-01 false Exhalation valve leakage test; minimum requirements... Chemical Cartridge Respirators § 84.204 Exhalation valve leakage test; minimum requirements. (a) Dry... normal operating position. (b) Leakage between the valve and valve seat shall not exceed 30...

  6. 49 CFR 176.710 - Care following leakage or sifting of radioactive materials.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 49 Transportation 2 2013-10-01 2013-10-01 false Care following leakage or sifting of radioactive... CARRIAGE BY VESSEL Detailed Requirements for Radioactive Materials § 176.710 Care following leakage or... segregated from unnecessary contact with personnel. In case of obvious leakage, or if the inside...

  7. 42 CFR 84.1150 - Exhalation valve leakage test; minimum requirements.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 42 Public Health 1 2012-10-01 2012-10-01 false Exhalation valve leakage test; minimum requirements... Combination Gas Masks § 84.1150 Exhalation valve leakage test; minimum requirements. (a) Dry exhalation valves... operating position. (b) Leakage between the valve and valve seat shall not exceed 30 milliliters per minute....

  8. 42 CFR 84.182 - Exhalation valve leakage test; minimum requirements.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 42 Public Health 1 2011-10-01 2011-10-01 false Exhalation valve leakage test; minimum requirements...-Powered Air-Purifying Particulate Respirators § 84.182 Exhalation valve leakage test; minimum requirements... height while in a normal operating position. (b) Leakage between the valve and valve seat shall...

  9. 42 CFR 84.1150 - Exhalation valve leakage test; minimum requirements.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 42 Public Health 1 2014-10-01 2014-10-01 false Exhalation valve leakage test; minimum requirements... Combination Gas Masks § 84.1150 Exhalation valve leakage test; minimum requirements. (a) Dry exhalation valves... operating position. (b) Leakage between the valve and valve seat shall not exceed 30 milliliters per minute....

  10. 42 CFR 84.182 - Exhalation valve leakage test; minimum requirements.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 42 Public Health 1 2014-10-01 2014-10-01 false Exhalation valve leakage test; minimum requirements...-Powered Air-Purifying Particulate Respirators § 84.182 Exhalation valve leakage test; minimum requirements... height while in a normal operating position. (b) Leakage between the valve and valve seat shall...

  11. 42 CFR 84.1150 - Exhalation valve leakage test; minimum requirements.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 42 Public Health 1 2010-10-01 2010-10-01 false Exhalation valve leakage test; minimum requirements... Combination Gas Masks § 84.1150 Exhalation valve leakage test; minimum requirements. (a) Dry exhalation valves... operating position. (b) Leakage between the valve and valve seat shall not exceed 30 milliliters per minute....

  12. 49 CFR 176.710 - Care following leakage or sifting of radioactive materials.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 49 Transportation 2 2014-10-01 2014-10-01 false Care following leakage or sifting of radioactive... CARRIAGE BY VESSEL Detailed Requirements for Radioactive Materials § 176.710 Care following leakage or... segregated from unnecessary contact with personnel. In case of obvious leakage, or if the inside...

  13. 47 CFR 76.611 - Cable television basic signal leakage performance criteria.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 47 Telecommunication 4 2012-10-01 2012-10-01 false Cable television basic signal leakage... television basic signal leakage performance criteria. (a) No cable television system shall commence or... one of the following cable television basic signal leakage performance criteria: (1) Prior to...

  14. 42 CFR 84.1150 - Exhalation valve leakage test; minimum requirements.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 42 Public Health 1 2013-10-01 2013-10-01 false Exhalation valve leakage test; minimum requirements... Combination Gas Masks § 84.1150 Exhalation valve leakage test; minimum requirements. (a) Dry exhalation valves... operating position. (b) Leakage between the valve and valve seat shall not exceed 30 milliliters per minute....

  15. 42 CFR 84.204 - Exhalation valve leakage test; minimum requirements.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 42 Public Health 1 2011-10-01 2011-10-01 false Exhalation valve leakage test; minimum requirements... Chemical Cartridge Respirators § 84.204 Exhalation valve leakage test; minimum requirements. (a) Dry... normal operating position. (b) Leakage between the valve and valve seat shall not exceed 30...

  16. 42 CFR 84.182 - Exhalation valve leakage test; minimum requirements.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 42 Public Health 1 2013-10-01 2013-10-01 false Exhalation valve leakage test; minimum requirements...-Powered Air-Purifying Particulate Respirators § 84.182 Exhalation valve leakage test; minimum requirements... height while in a normal operating position. (b) Leakage between the valve and valve seat shall...

  17. 42 CFR 84.204 - Exhalation valve leakage test; minimum requirements.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 42 Public Health 1 2014-10-01 2014-10-01 false Exhalation valve leakage test; minimum requirements... Chemical Cartridge Respirators § 84.204 Exhalation valve leakage test; minimum requirements. (a) Dry... normal operating position. (b) Leakage between the valve and valve seat shall not exceed 30...

  18. 42 CFR 84.204 - Exhalation valve leakage test; minimum requirements.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 42 Public Health 1 2013-10-01 2013-10-01 false Exhalation valve leakage test; minimum requirements... Chemical Cartridge Respirators § 84.204 Exhalation valve leakage test; minimum requirements. (a) Dry... normal operating position. (b) Leakage between the valve and valve seat shall not exceed 30...

  19. 47 CFR 76.611 - Cable television basic signal leakage performance criteria.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 47 Telecommunication 4 2010-10-01 2010-10-01 false Cable television basic signal leakage... television basic signal leakage performance criteria. (a) No cable television system shall commence or... one of the following cable television basic signal leakage performance criteria: (1) prior to...

  20. 49 CFR 176.710 - Care following leakage or sifting of radioactive materials.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 49 Transportation 2 2012-10-01 2012-10-01 false Care following leakage or sifting of radioactive... CARRIAGE BY VESSEL Detailed Requirements for Radioactive Materials § 176.710 Care following leakage or... segregated from unnecessary contact with personnel. In case of obvious leakage, or if the inside...

  1. 40 CFR 86.166-12 - Method for calculating emissions due to air conditioning leakage.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... to air conditioning leakage. 86.166-12 Section 86.166-12 Protection of Environment ENVIRONMENTAL... for calculating emissions due to air conditioning leakage. This section describes procedures used to determine a refrigerant leakage rate in grams per year from vehicle-based air conditioning units....

  2. 42 CFR 84.1150 - Exhalation valve leakage test; minimum requirements.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 42 Public Health 1 2011-10-01 2011-10-01 false Exhalation valve leakage test; minimum requirements... Combination Gas Masks § 84.1150 Exhalation valve leakage test; minimum requirements. (a) Dry exhalation valves... operating position. (b) Leakage between the valve and valve seat shall not exceed 30 milliliters per minute....

  3. 42 CFR 84.204 - Exhalation valve leakage test; minimum requirements.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 42 Public Health 1 2012-10-01 2012-10-01 false Exhalation valve leakage test; minimum requirements... Chemical Cartridge Respirators § 84.204 Exhalation valve leakage test; minimum requirements. (a) Dry... normal operating position. (b) Leakage between the valve and valve seat shall not exceed 30...

  4. 49 CFR 176.710 - Care following leakage or sifting of radioactive materials.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 2 2011-10-01 2011-10-01 false Care following leakage or sifting of radioactive... CARRIAGE BY VESSEL Detailed Requirements for Radioactive Materials § 176.710 Care following leakage or... segregated from unnecessary contact with personnel. In case of obvious leakage, or if the inside...

  5. 40 CFR 86.166-12 - Method for calculating emissions due to air conditioning leakage.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... to air conditioning leakage. 86.166-12 Section 86.166-12 Protection of Environment ENVIRONMENTAL... for calculating emissions due to air conditioning leakage. This section describes procedures used to determine a refrigerant leakage rate in grams per year from vehicle-based air conditioning units....

  6. 47 CFR 76.611 - Cable television basic signal leakage performance criteria.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 47 Telecommunication 4 2014-10-01 2014-10-01 false Cable television basic signal leakage... television basic signal leakage performance criteria. (a) No cable television system shall commence or... one of the following cable television basic signal leakage performance criteria: (1) Prior to...

  7. The over-pruning hypothesis of autism.

    PubMed

    Thomas, Michael S C; Davis, Rachael; Karmiloff-Smith, Annette; Knowland, Victoria C P; Charman, Tony

    2016-03-01

    This article outlines the over-pruning hypothesis of autism. The hypothesis originates in a neurocomputational model of the regressive sub-type (Thomas, Knowland & Karmiloff-Smith, 2011a, 2011b). Here we develop a more general version of the over-pruning hypothesis to address heterogeneity in the timing of manifestation of ASD, including new computer simulations which reconcile the different observed developmental trajectories (early onset, late onset, regression) via a single underlying atypical mechanism; and which show how unaffected siblings of individuals with ASD may differ from controls either by inheriting a milder version of the pathological mechanism or by co-inheriting the risk factors without the pathological mechanism. The proposed atypical mechanism involves overly aggressive synaptic pruning in infancy and early childhood, an exaggeration of a normal phase of brain development. We show how the hypothesis generates novel predictions that differ from existing theories of ASD including that (1) the first few months of development in ASD will be indistinguishable from typical, and (2) the earliest atypicalities in ASD will be sensory and motor rather than social. Both predictions gain cautious support from emerging longitudinal studies of infants at-risk of ASD. We review evidence consistent with the over-pruning hypothesis, its relation to other current theories (including C. Frith's under-pruning proposal; C. Frith, 2003, 2004), as well as inconsistent data and current limitations. The hypothesis situates causal accounts of ASD within a framework of protective and risk factors (Newschaffer et al., 2012); clarifies different versions of the broader autism phenotype (i.e. the implication of observed similarities between individuals with autism and their family members); and integrates data from multiple disciplines, including behavioural studies, neuroscience studies, genetics, and intervention studies. PMID:25845529

  8. Gas-path leakage seal for a turbine

    DOEpatents

    Bagepalli, Bharat Sampathkumaran; Aksit, Mahmut Faruk; Farrell, Thomas Raymond

    1999-01-01

    A gas-path leakage seal for generally sealing a gas-path leakage-gap between spaced-apart first and second members of a turbine (such as combustor casing segments of a gas turbine). The seal includes a flexible and generally imperforate metal sheet assemblage having opposing first and second surfaces and two opposing raised edges extending a generally identical distance above and below the surfaces. A first cloth layer assemblage has a thickness generally equal to the previously-defined identical distance and is superimposed on the first surface between the raised edges. A second cloth layer assemblage is generally identical to the first cloth layer assemblage and is superimposed on the second surface between the raised edges.

  9. Leakage current measurements of a pixelated polycrystalline CVD diamond detector

    NASA Astrophysics Data System (ADS)

    Zain, R. M.; Maneuski, D.; O'Shea, V.; Bates, R.; Blue, A.; Cunnigham, L.; Stehl, C.; Berderman, E.; Rahim, R. A.

    2013-01-01

    Diamond has several desirable features when used as a material for radiation detection. With the invention of synthetic growth techniques, it has become feasible to look at developing diamond radiation detectors with reasonable surface areas. Polycrystalline diamond has been grown using a chemical vapour deposition (CVD) technique by the University of Augsburg and detector structures fabricated at the James Watt Nanofabrication Centre (JWNC) in the University of Glasgow in order to produce pixelated detector arrays. The anode and cathode contacts are realised by depositing gold to produce ohmic contacts. Measurements of I-V characteristics were performed to study the material uniformity. The bias voltage is stepped from -1000V to 1000V to investigate the variation of leakage current from pixel to pixel. Bulk leakage current is measured to be less than 1nA.

  10. Remote laser detection of natural gas leakages from pipelines

    SciTech Connect

    Petukhov, V O; Gorobets, V A; Andreev, Yu M; Lanskii, G V

    2010-02-28

    A differential absorption lidar based on a tunable TEA CO{sub 2} laser emitting at 42 lines of the 'hot' 01{sup 1}1 - 11{sup 1}0 band in the range from 10.9 to 11.4 {mu}m is developed for detecting natural gas leakages from oil pipelines by measuring the ethane content in the atmosphere. The ethane detection sensitivity is 0.9 ppm km. The presence of methane does not distort the measurement results. The developed lidar can detect the natural gas leakage from kilometre heights at the flying velocities up to 200 km h{sup -1} and a probe pulse repetition rate of 5 Hz. (laser applications and other topics in quantum electronics)

  11. Gas-path leakage seal for a turbine

    DOEpatents

    Bagepalli, B.S.; Aksit, M.F.; Farrell, T.R.

    1999-08-10

    A gas-path leakage seal for generally sealing a gas-path leakage-gap between spaced-apart first and second members of a turbine (such as combustor casing segments of a gas turbine). The seal includes a flexible and generally imperforate metal sheet assemblage having opposing first and second surfaces and two opposing raised edges extending a generally identical distance above and below the surfaces. A first cloth layer assemblage has a thickness generally equal to the previously-defined identical distance and is superimposed on the first surface between the raised edges. A second cloth layer assemblage is generally identical to the first cloth layer assemblage and is superimposed on the second surface between the raised edges. 5 figs.

  12. Turbocharger with sliding piston, and having vanes and leakage dams

    DOEpatents

    Roberts, Quentin; Alnega, Ahmed

    2011-12-06

    A turbocharger having a sliding piston for regulating exhaust gas flow into the turbine wheel includes a set of first vanes mounted on a fixed first wall of the turbine nozzle and projecting axially toward an opposite second wall of the nozzle, and/or a set of second vanes mounted on the end of the piston and projecting in an opposite axial direction toward the first wall of the nozzle. For the/each set of vanes, there are leakage dams formed on the wall that is adjacent the vane tips when the piston is closed. The leakage dams are closely adjacent the vane tips and discourage exhaust gas from leaking in a generally radial direction past the vane tips as the piston just begins to open from its fully closed position.

  13. Energetic magnetospheric ions at the dayside magnetopause - Leakage or merging?

    NASA Technical Reports Server (NTRS)

    Sibeck, D. G.; Mcentire, R. W.; Lui, A. T. Y.; Lopez, R. E.; Krimigis, S. M.

    1987-01-01

    The leakage model for the escape of energetic magnetospheric particles into the magnetosheath is described, making comparisons with the merging model where possible. Reported observations of energetic particles at the dayside magnetopause are reexamined, and it is concluded that they do not conclusively support the merging model, either on a case-by-case basis or statistically. New observations made by the Charge Composition Explorer satellite during the Active Magnetospheric Particle Tracer Explorers program are presented. They indicate that magnetospheric ions of all species steadily escape into the magnetosheath and stream away from the magnetopause, regardless of the magnetosheath magnetic field orientation. It is concluded that the leakage model explains both the new and old observations at least as well as, or better than, the merging model.

  14. An excitatory synapse hypothesis of depression

    PubMed Central

    Thompson, Scott M.; Kallarackal, Angy J.; Kvarta, Mark D.; Van Dyke, Adam M.; LeGates, Tara A.; Cai, Xiang

    2015-01-01

    Depression is a common cause of mortality and morbidity, but the biological bases of the deficits in emotional and cognitive processing remain incompletely understood. Current antidepressant therapies are effective in only some patients and act slowly. We propose an excitatory synapse hypothesis of depression in which chronic stress and genetic susceptibility cause changes in the strength of subsets of glutamatergic synapses at multiple locations, including the prefrontal cortex, hippocampus and nucleus accumbens, leading to a dysfunction of cortico-mesolimbic reward circuitry that underlies many of the symptoms of depression. This hypothesis accounts for current depression treatments and suggests an updated framework for the development of better therapeutic compounds. PMID:25887240

  15. Migraine: the platelet hypothesis after 10 years.

    PubMed

    Hanington, E

    1989-01-01

    The proposal that migraine is a blood disorder and caused by a primary abnormality of platelet behaviour was first put forward in 1978. This paper outlines the basis on which the proposal was made and the way in which the platelet hypothesis can account for the many facets of the disorder. It also reports further studies of platelet composition and function which have been undertaken by a large number of independent workers during the past ten years. The results of their investigations provide strong additional support for the platelet hypothesis in migraine.

  16. Binding and leakage of barium in alginate microbeads.

    PubMed

    Mørch, Yrr A; Qi, Meirigeng; Gundersen, Per Ole M; Formo, Kjetil; Lacik, Igor; Skjåk-Braek, Gudmund; Oberholzer, Jose; Strand, Berit L

    2012-11-01

    Microbeads of alginate crosslinked with Ca(2+) and/or Ba(2+) are popular matrices in cell-based therapy. The aim of this study was to quantify the binding of barium in alginate microbeads and its leakage under in vitro and accumulation under in vivo conditions. Low concentrations of barium (1 mM) in combination with calcium (50 mM) and high concentrations of barium (20 mM) in gelling solutions were used for preparation of microbeads made of high-G and high-M alginates. High-G microbeads accumulated barium from gelling solution and contained higher concentrations of divalent ions for both low- and high-Ba exposure compared with high-G microbeads exposed to calcium solely and to high-M microbeads for all gelling conditions. Although most of the unbound divalent ions were removed during the wash and culture steps, leakage of barium was still detected during storage. Barium accumulation in blood and femur bone of mice implanted with high-G beads was found to be dose-dependent. Estimated barium leakage relevant to transplantation to diabetic patients with islets in alginate microbeads showed that the leakage was 2.5 times lower than the tolerable intake value given by WHO for high-G microbeads made using low barium concentration. The similar estimate gave 1.5 times higher than is the tolerable intake value for the high-G microbeads made using high barium concentration. To reduce the risk of barium accumulation that may be of safety concern, the microbeads made of high-G alginate gelled with a combination of calcium and low concentration of barium ions is recommended for islet transplantation.

  17. Binding and Leakage of Barium in Alginate Microbeads

    PubMed Central

    Mørch, Yrr A.; Qi, Meirigeng; Gundersen, Per Ole M.; Formo, Kjetil; Lacik, Igor; Skjåk-Bræk, Gudmund; Oberholzer, Jose; Strand, Berit L.

    2013-01-01

    Microbeads of alginate cross-linked with Ca2+ and/or Ba2+ are popular matrices in cell-based therapy. The aim of this study was to quantify the binding of barium in alginate microbeads and its leakage under in vitro and accumulation under in vivo conditions. Low concentrations of barium (1 mM) in combination with calcium (50 mM) and high concentrations of barium (20 mM) in gelling solutions were used for preparation of microbeads made of high-G and high-M alginates. High-G microbeads accumulated barium from gelling solution and contained higher concentrations of divalent ions for both low- and high-Ba exposure compared to high-G microbeads exposed to calcium solely and to high-M microbeads for all gelling conditions. Although most of the unbound divalent ions were removed during the wash and culture steps, leakage of barium was still detected during storage. Barium accumulation in blood and femur bone of mice implanted with high-G beads was found to be dose-dependent. Estimated barium leakage relevant to transplantation to diabetic patients with islets in alginate microbeads showed that the leakage was 2.5 times lower than the tolerable intake value given by WHO for high-G microbeads made using low barium concentration. The similar estimate gave 1.5 times higher than is the tolerable intake value for the high-G microbeads made using high barium concentration. In order to reduce the risk of barium accumulation that may be of safety concern, the microbeads made of high-G alginate gelled with a combination of calcium and low concentration of barium ions is recommended for islet transplantation. PMID:22700168

  18. Determining corrosion defect geometry from magnetic flux leakage pig data

    SciTech Connect

    Nestleroth, J.B.; Rust, S.W.; Burgoon, D.A.; Haines, H.

    1996-08-01

    Accurate determination of the size of corrosion defects is important for determining defect severity. Many magnetic flux leakage pigs employ strong magnetizers and a large number of sensors for improved defect geometry determination methods. Analysis of data from 128 metal loss defects examined repeatedly under different test conditions is used to illustrate pig performance capabilities. An assessment of two inspection variables that can degrade performance is also presented.

  19. CO2 leakage risk in 3D heterogeneous formations

    NASA Astrophysics Data System (ADS)

    Hou, Z.; Murray, C. J.; Rockhold, M. L.

    2011-12-01

    In this study we use a stochastic sensitivity analysis framework to evaluate the impact of 3D spatial heterogeneity in permeability on CO2 leakage risk. The leakage is defined as the total mass of CO2 moving into the overburden through the caprock-overburden interface, in both gaseous and liquid (dissolved) phases. The entropy-based framework has the ability to quantify the uncertainty associated with the input parameters/factors in the form of prior pdfs (probability density functions). Effective sampling of the prior pdfs enables us to explore the parameter space and systematically evaluate the individual and combined effects of the factors/parameters of interest on CO2 leakage risk. The parameters that are considered in the study include: mean, variance, and horizontal to vertical spatial anisotropy ratio for caprock permeability, and those same parameters for reservoir permeability. Given the sampled spatial variogram parameters, multiple realizations of permeability fields were generated using GSLIB subroutines. For each permeability field, a numerical simulator STOMP (water-salt-CO2-energy operational mode) is used to simulate the CO2 migration within the reservoir and caprock up to 50 years after injection. Due to intensive computational demand, a scalable version simulator, eSTOMP, is run on the Jaguar supercomputer. We then perform statistical analyses and summarize the relationships between the parameters of interest (mean/variance/anisotropy ratio of caprock/reservoir permeability) and CO2 leakage ratio. We will also present the effects of those parameters on CO2 plume radius and reservoir injectivity.

  20. Alternative magnetic flux leakage modalities for pipeline inspection

    SciTech Connect

    Katragadda, G.; Lord, W.; Sun, Y.S.; Udpa, S.; Udpa, L.

    1996-05-01

    Increasing quality consciousness is placing higher demands on the accuracy and reliability of inspection systems used in defect detection and characterization. Nondestructive testing techniques often rely on using multi-transducer approaches to obtain greater defect sensitivity. This paper investigates the possibility of taking advantage of alternative modalities associated with the standard magnetic flux leakage tool to obtain additional defect information, while still using a single excitation source.

  1. Giant mid-esophageal diverticulum. Conservative treatment of postoperative leakage.

    PubMed

    Dallatomasina, S; Casaccia, M; Chessa, M; Serrano, J; Nardi, I; Troilo, B; Miggino, M; Valente, U

    2009-01-01

    Mid-esophageal diverticula are rare entities. Only symptomatic patients usually receive surgical treatment. Esophageal leakage is one of the most common complications after these procedures. Though in literature, operative management is the preferred treatment for esophageal fistula, conservative approach is described in case of small leaks. We report a case of an operated giant mid-esophageal diverticulum complicated with an esophageal fistula. The patient underwent a surgical treatment and recovered completely.

  2. Dual-Diaphragm Tank With Leakage-Indicating Drain

    NASA Technical Reports Server (NTRS)

    Tuthill, Wallace C., Jr.

    1991-01-01

    Proposed tank includes dual diaphragm with telltale drain to separate two fluids. If leak occurred in one diaphragm, other diaphragm prevents mixing of two fluids; meanwhile, leakage accumulates in drain and alerts inspector to need for repair. Conceived for bladder tanks for use in zero gravity, concept adaptable to such commercial uses as hydraulic accumulators in industrial hydraulic systems, hydraulic systems in aircraft, and water pressure tanks.

  3. Bacterial coronal leakage after obturation with three root canal sealers.

    PubMed

    Timpawat, S; Amornchat, C; Trisuwan, W R

    2001-01-01

    The purpose of this study was to compare the bacterial leakage of root canals obturated with three root canal sealers, using Endodontalis faecalis as a microbial tracer to determine the length of time for bacteria to penetrate through the obturated root canal to the root apex. Seventy-five, single-rooted teeth with straight root canals had the crown cut off at the cementoenamel junction. Root canals were instrumented by a step-back technique. The prepared teeth were randomly divided into 3 groups of 19 teeth each and another 2 groups as positive and negative controls (9 teeth each). The experimental groups were dependent on the sealer used: AH-Plus, Apexit, and Ketac-Endo. The root canals were obturated using a lateral condensation technique. After 24 h the teeth were attached to microcentrifuge tubes with 2 mm of the root apex submerged in Brain Heart Infusion broth in glass test tubes. The coronal portions of the root canal filling materials were placed in contact with E. faecalis. The teeth were observed for bacterial leakage daily for 30 and 60 days. With the chi2 test for comparing pairs of groups at the 0.05 level (p < 0.05), there was no statistical difference between Ketac-Endo and AH-Plus (p > 0.06), but Apexit had significantly higher leakage (p < 0.05) at 30 days. After 60 days there was no statistical difference between Ketac-Endo and Apexit (p > 0.05), but Apexit leaked more than AH-Plus. The conclusion drawn from this experiment was that epoxy resin root canal sealer was found to be more adaptable to the root canal wall and filling material than a calcium hydroxide sealer when bacterial coronal leakage was studied.

  4. The energy impact of air leakage through insulated walls

    SciTech Connect

    Bhattacharyya, S.; Claridge, D.E.

    1995-08-01

    Infiltration is customarily assumed to increase the heating and cooling load of a building by an amount equal to the mass flow rate of the infiltration times the enthalpy difference between the inside and outside air--with the latent portion of the enthalpy difference sometimes neglected. An experimental and analytical investigation has been conducted on the actual energy impact of air leakage on a well-characterized insulated stud-cavity wall specimen. Calorimetric measurements conducted on the specimen with measured amounts of air leakage introduced under a variety of controlled conditions and configurations verify earlier test cell measurements showing that infiltration heat exchange can lead to a much smaller change in the energy load due to infiltration than is customarily calculated and show the dependence of infiltration heat exchange on flow rate and path length. A analytical model based on fundamental heat and mass transfer principles has been developed and the predicted values of Infiltration Heat Exchange Effectiveness, {var_epsilon}, as a function of air flow rates and effective path length for five study-cavity wall specimen test configurations were consistent with the experimental results. Significant experimental results include: (i) {epsilon} values in the 0.16--0.7 range in the stud-cavity and (ii) {epsilon} values of 0.16 to 0.34 for air exiting the stud-cavity directly across from the entry. These results indicate that significant heat recovery is probable for most leakage occurring through insulated stud cavities.

  5. Air Leakage and Air Transfer Between Garage and Living Space

    SciTech Connect

    Rudd, Armin

    2014-09-01

    This research project focused on evaluation of air transfer between the garage and living space in a single-family detached home constructed by a production homebuilder in compliance with the 2009 International Residential Code and the 2009 International Energy Conservation Code. The project gathered important information about the performance of whole-building ventilation systems and garage ventilation systems as they relate to minimizing flow of contaminated air from garage to living space. A series of 25 multi-point fan pressurization tests and additional zone pressure diagnostic testing characterized the garage and house air leakage, the garage-to-house air leakage, and garage and house pressure relationships to each other and to outdoors using automated fan pressurization and pressure monitoring techniques. While the relative characteristics of this house may not represent the entire population of new construction configurations and air tightness levels (house and garage) throughout the country, the technical approach was conservative and should reasonably extend the usefulness of the results to a large spectrum of house configurations from this set of parametric tests in this one house. Based on the results of this testing, the two-step garage-to-house air leakage test protocol described above is recommended where whole-house exhaust ventilation is employed.

  6. Using Biomineralization Sealing for Leakage Mitigation in Shale

    NASA Astrophysics Data System (ADS)

    Gerlach, R.; Rothman, A.; Hiebert, R.; Cunningham, A. B.

    2013-12-01

    Estimates of the number of abandoned wells in the U.S and abroad range in the millions, all of which have a high probability of leaking at some point during their lifetime. We are currently focusing on developing technologies for sealing unwanted leakage pathways in fractured shales. We are investigating the feasibility of a plugging technology, which is based on the microbially-induced precipitation of carbonate minerals. Microbes can hydrolyze urea to ultimately change the saturation state of various minerals, including carbonates, such as calcium carbonate. The resulting biocement (calcium carbonate) has been demonstrated by us to cement together heavily fractured shale and drastically reduce the permeability of fractures in shale cores. We propose this technology for mitigating leakage from abandoned wells and as an alternative to more traditional, cement-based plugging technologies. We have demonstrated the principal feasibility of this technology for ensuring geologic CO2 storage in deep saline aquifers through the plugging of small aperture leaks such as fractures or delamination interfaces in the vicinity of injection wells. Fractured shale might reduce production efficiency as well as pose a risk to the environment due to leakage of hydrocarbons in the form of gas and liquid. The biomineralization technology can be delivered via low viscosity fluids and could potentially have significant advantages including a time- and space-dependent placement of biocement plugs in the immediate vicinity of wells as well as further away from the wellbore in the rock formation.

  7. Surface Leakage Mechanisms in III-V Infrared Barrier Detectors

    NASA Astrophysics Data System (ADS)

    Sidor, D. E.; Savich, G. R.; Wicks, G. W.

    2016-09-01

    Infrared detector epitaxial structures employing unipolar barriers exhibit greatly reduced dark currents compared to simple pn-based structures. When correctly positioned within the structure, unipolar barriers are highly effective at blocking bulk dark current mechanisms. Unipolar barriers are also effective at suppressing surface leakage current in infrared detector structures employing absorbing layers that possess the same conductivity type in their bulk and at their surface. When an absorbing layer possesses opposite conductivity types in its bulk and at its surface, unipolar barriers are not solutions to surface leakage. This work reviews empirically determined surface band alignments of III-V semiconductor compounds and modeled surface band alignments of both gallium-free and gallium-containing type-II strained layer superlattice material systems. Surface band alignments are used to predict surface conductivity types in several detector structures, and the relationship between surface and bulk conductivity types in the absorbing layers of these structures is used as the basis for explaining observed surface leakage characteristics.

  8. Geochemical implications of brine leakage into freshwater aquifers.

    PubMed

    Wunsch, Assaf; Navarre-Sitchler, Alexis K; McCray, John E

    2013-01-01

    CO(2) injection into deep saline formations as a way to mitigate climate change raises concerns that leakage of saline waters from the injection formations will impact water quality of overlying aquifers, especially underground sources of drinking water (USDWs). This paper aims to characterize the geochemical composition of deep brines, with a focus on constituents that pose a human health risk and are regulated by the U.S. Environmental Protection Agency (USEPA). A statistical analysis of the NATCARB brine database, combined with simple mixing model calculations, show total dissolved solids and concentrations of chloride, boron, arsenic, sulfate, nitrate, iron and manganese may exceed plant tolerance or regulatory levels. Twelve agricultural crops evaluated for decreased productivity in the event of brine leakage would experience some yield reduction due to increased TDS at brine-USDW ratios of < 0.1, and a 50% yield reduction at < 0.2 brine-USDW ratio. A brine-USDW ratio as low as 0.004 may result in yield reduction in the most sensitive crops. The USEPA TDS secondary standard is exceeded at a brine fraction of approximately 0.002. To our knowledge, this is the first study to consider agricultural impacts of brine leakage, even though agricultural withdrawals of groundwater in the United States are almost three times higher than public and domestic withdrawals.

  9. Indoor-Outdoor Air Leakage of Apartments and Commercial Buildings

    SciTech Connect

    Price, P.N.; Shehabi, A.; Chan, R.W.; Gadgil, A.J.

    2006-06-01

    We compiled and analyzed available data concerning indoor-outdoor air leakage rates and building leakiness parameters for commercial buildings and apartments. We analyzed the data, and reviewed the related literature, to determine the current state of knowledge of the statistical distribution of air exchange rates and related parameters for California buildings, and to identify significant gaps in the current knowledge and data. Very few data were found from California buildings, so we compiled data from other states and some other countries. Even when data from other developed countries were included, data were sparse and few conclusive statements were possible. Little systematic variation in building leakage with construction type, building activity type, height, size, or location within the u.s. was observed. Commercial buildings and apartments seem to be about twice as leaky as single-family houses, per unit of building envelope area. Although further work collecting and analyzing leakage data might be useful, we suggest that a more important issue may be the transport of pollutants between units in apartments and mixed-use buildings, an under-studied phenomenon that may expose occupants to high levels of pollutants such as tobacco smoke or dry cleaning fumes.

  10. Sensitivity of the house pressure test for duct leakage to variations in the distribution of air leakage in the house envelope

    SciTech Connect

    Andrews, J.W.

    1998-12-01

    The house pressure test for air leakage in ducts calculates the signed difference between the supply and return leakage from the response of the air pressure in the house to operation of the system fan. The currently accepted version of this calculation was based on particular assumptions about how the house envelope leakage is distributed between the walls, ceiling, and floor. This report generalizes the equation to account for an arbitrary distribution of envelope leakage. It concludes that the currently accepted equation is usually accurate to within {+-}5%, but in a small proportion of cases the results may diverge by 50% or more.

  11. Relationship between Leakage Current and Pollution Deposits on the Surface of Polymeric Insulator

    NASA Astrophysics Data System (ADS)

    Miyake, Takuma; Seo, Yuya; Sakoda, Tatsuya; Otsubo, Masahisa

    Application of polymeric materials used for housing insulators is considered. However, because polymeric insulator is organic matter, the aged deterioration is anxious. The lifetime of polymeric insulator is influenced by environmental conditions such as ultraviolet, acid rain, and polluted deposits. A change of the surface condition of polymeric material causes the dry band arc discharge and the discharge may lower the insulation strength. To investigate the relationship between insoluble pollution and occurrence of dry band arc discharge, we performed a salt-fog test with ethylene vinyl acetate (EVA) samples. The results showed that the heavy erosion caused by frequent dry band arc discharges occurred even in the case of a light polluted condition. Additionally, a very characteristic increase tendency in leakage current with a period of about 5 h was observed during the mist period.

  12. Hypothesis Formation and Testing in Clinical Judgment.

    ERIC Educational Resources Information Center

    Strohmer, Douglas C.; And Others

    1983-01-01

    Examined the influence of cognitive complexity and client observation on the quality of clinical hypotheses counselors develop and the number of questions generated to test them. Results showed no effect of these variables on hypothesis quality; but a significant interaction between client observations on the number of questions developed. (LLL)

  13. The Hypothesis of Incommensurability and Multicultural Education

    ERIC Educational Resources Information Center

    McDonough, Tim

    2009-01-01

    This article describes the logical and rhetorical grounds for a multicultural pedagogy that teaches students the knowledge and skills needed to interact creatively in the public realm betwixt and between cultures. I begin by discussing the notion of incommensurability. I contend that this hypothesis was intended to perform a particular rhetorical…

  14. In Defense of Chi's Ontological Incompatibility Hypothesis

    ERIC Educational Resources Information Center

    Slotta, James D.

    2011-01-01

    This article responds to an article by A. Gupta, D. Hammer, and E. F. Redish (2010) that asserts that M. T. H. Chi's (1992, 2005) hypothesis of an "ontological commitment" in conceptual development is fundamentally flawed. In this article, I argue that Chi's theoretical perspective is still very much intact and that the critique offered by Gupta…

  15. Diagnostic Hypothesis Generation and Human Judgment

    ERIC Educational Resources Information Center

    Thomas, Rick P.; Dougherty, Michael R.; Sprenger, Amber M.; Harbison, J. Isaiah

    2008-01-01

    Diagnostic hypothesis-generation processes are ubiquitous in human reasoning. For example, clinicians generate disease hypotheses to explain symptoms and help guide treatment, auditors generate hypotheses for identifying sources of accounting errors, and laypeople generate hypotheses to explain patterns of information (i.e., data) in the…

  16. Hypothesis on the nature of atmospheric UFOs

    NASA Astrophysics Data System (ADS)

    Mukharev, L. A.

    1991-08-01

    A hypothesis is developed according to which the atmospheric UFO phenomenon has an electromagnetic nature. It is suggested that an atmospheric UFO is an agglomeration of charged atmospheric dust within which there exists a slowly damped electromagnetic field. This field is considered to be the source of the observed optical effects and the motive force of the UFO.

  17. Forty Years Later: Updating the Fossilization Hypothesis

    ERIC Educational Resources Information Center

    Han, ZhaoHong

    2013-01-01

    A founding concept in second language acquisition (SLA) research, fossilization has been fundamental to understanding second language (L2) development. The Fossilization Hypothesis, introduced in Selinker's seminal text (1972), has thus been one of the most influential theories, guiding a significant bulk of SLA research for four decades; 2012…

  18. A Developmental Study of the Infrahumanization Hypothesis

    ERIC Educational Resources Information Center

    Martin, John; Bennett, Mark; Murray, Wayne S.

    2008-01-01

    Intergroup attitudes in children were examined based on Leyen's "infrahumanization hypothesis". This suggests that some uniquely human emotions, such as shame and guilt (secondary emotions), are reserved for the in-group, whilst other emotions that are not uniquely human and shared with animals, such as anger and pleasure (primary emotions), are…

  19. Sleep memory processing: the sequential hypothesis

    PubMed Central

    Giuditta, Antonio

    2014-01-01

    According to the sequential hypothesis (SH) memories acquired during wakefulness are processed during sleep in two serial steps respectively occurring during slow wave sleep (SWS) and rapid eye movement (REM) sleep. During SWS memories to be retained are distinguished from irrelevant or competing traces that undergo downgrading or elimination. Processed memories are stored again during REM sleep which integrates them with preexisting memories. The hypothesis received support from a wealth of EEG, behavioral, and biochemical analyses of trained rats. Further evidence was provided by independent studies of human subjects. SH basic premises, data, and interpretations have been compared with corresponding viewpoints of the synaptic homeostatic hypothesis (SHY). Their similarities and differences are presented and discussed within the framework of sleep processing operations. SHY’s emphasis on synaptic renormalization during SWS is acknowledged to underline a key sleep effect, but this cannot marginalize sleep’s main role in selecting memories to be retained from downgrading traces, and in their integration with preexisting memories. In addition, SHY’s synaptic renormalization raises an unsolved dilemma that clashes with the accepted memory storage mechanism exclusively based on modifications of synaptic strength. This difficulty may be bypassed by the assumption that SWS-processed memories are stored again by REM sleep in brain subnuclear quantum particles. Storing of memories in quantum particles may also occur in other vigilance states. Hints are provided on ways to subject the quantum hypothesis to experimental tests. PMID:25565985

  20. Vacuum counterexamples to the cosmic censorship hypothesis

    SciTech Connect

    Miller, B.D.

    1981-07-01

    In cylindrically symmetric vacuum spacetimes it is possible to specify nonsingular initial conditions such that timelike singularities will (necessarily) evolve from these conditions. Examples are given; the spacetimes are somewhat analogous to one of the spherically symmetric counterexamples to the cosmic censorship hypothesis.

  1. A new hypothesis on HIV cure

    PubMed Central

    Hladik, Florian

    2015-01-01

    In this opinion article, I provide the rationale for my hypothesis that nucleoside reverse transcriptase inhibitors (NRTIs) may prevent human immunodeficiency virus (HIV) cure by promoting the survival of cells with integrated provirus. If correct, we may be closer to a cure than we realize. PMID:26380071

  2. The Marathon Group Hypothesis: An Unanswered Question

    ERIC Educational Resources Information Center

    Marks, Stephen E.; And Others

    1973-01-01

    The authors of this article contend that the Guinan and Foulds study was inadequately designed and executed, and the results indicate little of the "usefulness" of the test, much less illuminate the important hypothesis central to the investigation. Specific suggestions for further research in marathon group evaluation are made. (Author)

  3. Television Exposure Measures and the Cultivation Hypothesis.

    ERIC Educational Resources Information Center

    Potter, W. James; Chang, Ik Chin

    1990-01-01

    Describes study of students in grades 8 through 12 that was conducted to determine the degree to which television messages influence a person's construction of reality (the cultivation hypothesis). Research methodology that tests the effects of television exposure is examined with emphasis on the importance of demographic control variables. (38…

  4. Perceived Reality and the Cultivation Hypothesis.

    ERIC Educational Resources Information Center

    Potter, W. James

    1986-01-01

    Tested cultivation hypothesis by studying relationships between amount of television viewing by high school students and college students and their estimates of chances of victimization and causes of death. Stepwise multiple regression analyses were performed to determine importance of perceived reality, demographic, and televison viewing measures…

  5. Trouble for the most attractive channel hypothesis

    NASA Astrophysics Data System (ADS)

    Holdom, B.; Roux, F. S.

    1999-01-01

    We show that the next-to-leading corrections to the kernel of the gap equation can be large and of opposite sign to the lowest order kernel, in the presence of a gauge boson mass. This calls into question the reliability of the most attractive channel hypothesis.

  6. Total inward leakage of nanoparticles through filtering facepiece respirators.

    PubMed

    Rengasamy, Samy; Eimer, Benjamin C

    2011-04-01

    Nanoparticle (<100 nm size) exposure in workplaces is a major concern because of the potential impact on human health. National Institute for Occupational Safety and Health (NIOSH)-approved particulate respirators are recommended for protection against nanoparticles based on their filtration efficiency at sealed conditions. Concerns have been raised on the lack of information for face seal leakage of nanoparticles, compromising respiratory protection in workplaces. To address this issue, filter penetration and total inward leakage (TIL) through artificial leaks were measured for NIOSH-approved N95 and P100 and European certified Conformit'e Europe'en-marked FFP2 and FFP3 filtering facepiece respirator models sealed to a breathing manikin kept inside a closed chamber. Monodisperse sucrose aerosols (8-80 nm size) generated by electrospray or polydisperse NaCl aerosols (20-1000 nm size) produced by atomization were passed into the chamber. Filter penetration and TIL were measured at 20, 30, and 40 l min(-1) breathing flow rates. The most penetrating particle size (MPPS) was ∼50 nm and filter penetrations for 50 and 100 nm size particles were markedly higher than the penetrations for 8 and 400 nm size particles. Filter penetrations increased with increasing flow rates. With artificially introduced leaks, the TIL values for all size particles increased with increasing leak sizes. With relatively smaller size leaks, the TIL measured for 50 nm size particles was ∼2-fold higher than the values for 8 and 400 nm size particles indicating that the TIL for the most penetrating particles was higher than for smaller and larger size particles. The data indicate that higher concentration of nanoparticles could occur inside the breathing zone of respirators in workplaces where nanoparticles in the MPPS range are present, when leakage is minimal compared to filter penetration. The TIL/penetration ratios obtained for 400 nm size particles were larger than the ratios obtained for

  7. Einstein's Revolutionary Light-Quantum Hypothesis

    NASA Astrophysics Data System (ADS)

    Stuewer, Roger H.

    2005-05-01

    The paper in which Albert Einstein proposed his light-quantum hypothesis was the only one of his great papers of 1905 that he himself termed ``revolutionary.'' Contrary to widespread belief, Einstein did not propose his light-quantum hypothesis ``to explain the photoelectric effect.'' Instead, he based his argument for light quanta on the statistical interpretation of the second law of thermodynamics, with the photoelectric effect being only one of three phenomena that he offered as possible experimental support for it. I will discuss Einstein's light-quantum hypothesis of 1905 and his introduction of the wave-particle duality in 1909 and then turn to the reception of his work on light quanta by his contemporaries. We will examine the reasons that prominent physicists advanced to reject Einstein's light-quantum hypothesis in succeeding years. Those physicists included Robert A. Millikan, even though he provided convincing experimental proof of the validity of Einstein's equation of the photoelectric effect in 1915. The turning point came after Arthur Holly Compton discovered the Compton effect in late 1922, but even then Compton's discovery was contested both on experimental and on theoretical grounds. Niels Bohr, in particular, had never accepted the reality of light quanta and now, in 1924, proposed a theory, the Bohr-Kramers-Slater theory, which assumed that energy and momentum were conserved only statistically in microscopic interactions. Only after that theory was disproved experimentally in 1925 was Einstein's revolutionary light-quantum hypothesis generally accepted by physicists---a full two decades after Einstein had proposed it.

  8. Cortical Neural Computation by Discrete Results Hypothesis

    PubMed Central

    Castejon, Carlos; Nuñez, Angel

    2016-01-01

    One of the most challenging problems we face in neuroscience is to understand how the cortex performs computations. There is increasing evidence that the power of the cortical processing is produced by populations of neurons forming dynamic neuronal ensembles. Theoretical proposals and multineuronal experimental studies have revealed that ensembles of neurons can form emergent functional units. However, how these ensembles are implicated in cortical computations is still a mystery. Although cell ensembles have been associated with brain rhythms, the functional interaction remains largely unclear. It is still unknown how spatially distributed neuronal activity can be temporally integrated to contribute to cortical computations. A theoretical explanation integrating spatial and temporal aspects of cortical processing is still lacking. In this Hypothesis and Theory article, we propose a new functional theoretical framework to explain the computational roles of these ensembles in cortical processing. We suggest that complex neural computations underlying cortical processing could be temporally discrete and that sensory information would need to be quantized to be computed by the cerebral cortex. Accordingly, we propose that cortical processing is produced by the computation of discrete spatio-temporal functional units that we have called “Discrete Results” (Discrete Results Hypothesis). This hypothesis represents a novel functional mechanism by which information processing is computed in the cortex. Furthermore, we propose that precise dynamic sequences of “Discrete Results” is the mechanism used by the cortex to extract, code, memorize and transmit neural information. The novel “Discrete Results” concept has the ability to match the spatial and temporal aspects of cortical processing. We discuss the possible neural underpinnings of these functional computational units and describe the empirical evidence supporting our hypothesis. We propose that fast

  9. Exploiting multi-proxy analysis of marine sediments in the southeast Atlantic: Intensification of Agulhas leakage tied to the start of the 100ka cycles.

    NASA Astrophysics Data System (ADS)

    Petrick, Benjamin; McClymont, Erin; Marret, Fabienne

    2013-04-01

    The transition in orbital forcing from a 41 ka world to a 100 ka world was a major change in the climate regime over the last 1.5 Ma but its causes and its impacts are still being investigated. Here, we present reconstructions of sea-surface temperature (SST), salinity, and plankton assemblages obtained from a single core, ODP site 1087 (31°28'S, 15°19'E, 1374m water depth) spanning the last 1.5 Ma. Our hypothesis is that the response and position of the Agulhas leakage, which transfers heat and salt to the SE Atlantic region, has shifted as a result of changes in the dominant periodicity of orbital forcing. We draw on evidence from the alkenone (U37K') proxy for SST, dinoflagllate species analysis, and foraminifera oxygen isotopes for salinity and ice volume, to identify changes in the input of the Agulhas leakage to the SE Atlantic. We present the first continuous record of SE Atlantic SSTs reaching to 1.5 Ma which spans both the 41 kyr and 100 kyr glacial cycles. We identify large changes in SST and salinity on glacial-interglacial timescales, but show that there is a consistent pattern of SSTs leading salinity and then global ice volume change, so that deglaciation occurs some 5-10 kyr after the onset of rapid warming in the SE Atlantic during the recent glacials and interglacials. This early warming pattern, which characterizes the most recent cycles, began to develop as early at 900 ka, as the 100 kyr cycles became dominant. Before this time there is little evidence of Agulhas leakage in the ODP1087 record. We also show that over the last 600 ka there has been a strengthening of the Agulhas Leakage which has led to warmer interglacials over this time period. Overall the record shows that the strength and location of the Agulhas leakage is sensitive to changes in the dominant cycles in the climate.

  10. The GAIA Hypothesis and Chaos in Daisyworld.

    NASA Astrophysics Data System (ADS)

    Flynn, Cathal Michael

    1993-01-01

    To correctly model the climate it is necessary to include the effects of the biosphere. The Gaia hypothesis claims that the earth's living matter, air, oceans, and land form a complex system which has the capacity to regulate the earth's climate. A model developed by Lovelock and Watson to demonstrate the Gaia hypothesis is explained and the results of their work are reviewed. Only steady state behavior is observed in the Daisyworld model. The work of Zeng et al. on the presence of chaos in Daisyworld is reviewed as an introduction to our own work. The presence of oscillatory and even chaotic behavior in this Daisyworld model brings into question the Gaia hypothesis. We develop a model of two-dimensional crystal growth called Crystalworld. The Crystalworld model is similar to the Daisyworld model in that there is a coupling between the growing entities and their environment via temperature. The results of this model are similar to that of the Daisyworld model. We present the results of another modified model of Daisyworld which we developed. This modified model takes into account the finite response time of the daisies to changes in the planet's climatic conditions. With a generation time introduced into the model equations, while retaining the differential equation format, it is found that the system can show oscillatory and chaotic behavior. These results show that any climate-biosphere model must contain a time delay and that such a time delay leads to behavior which contradicts the Gaia hypothesis. In order to determine the effects of introducing more species we develop a model with two species of daisies and a parasite species. For this Parasite-Daisyworld model steady state, periodic and chaotic behavior is found. A comparison between the results of this model and that of Zeng et al. is made. The results of the Parasite-Daisyworld model show that increasing the number of species does not lead to increased regulation. This contradicts the Gaia hypothesis and

  11. Monetizing Leakage Risk of Geologic CO2 Storage using Wellbore Permeability Frequency Distributions

    NASA Astrophysics Data System (ADS)

    Bielicki, Jeffrey; Fitts, Jeffrey; Peters, Catherine; Wilson, Elizabeth

    2013-04-01

    Carbon dioxide (CO2) may be captured from large point sources (e.g., coal-fired power plants, oil refineries, cement manufacturers) and injected into deep sedimentary basins for storage, or sequestration, from the atmosphere. This technology—CO2 Capture and Storage (CCS)—may be a significant component of the portfolio of technologies deployed to mitigate climate change. But injected CO2, or the brine it displaces, may leak from the storage reservoir through a variety of natural and manmade pathways, including existing wells and wellbores. Such leakage will incur costs to a variety of stakeholders, which may affect the desirability of potential CO2 injection locations as well as the feasibility of the CCS approach writ large. Consequently, analyzing and monetizing leakage risk is necessary to develop CCS as a viable technological option to mitigate climate change. Risk is the product of the probability of an outcome and the impact of that outcome. Assessment of leakage risk from geologic CO2 storage reservoirs requires an analysis of the probabilities and magnitudes of leakage, identification of the outcomes that may result from leakage, and an assessment of the expected economic costs of those outcomes. One critical uncertainty regarding the rate and magnitude of leakage is determined by the leakiness of the well leakage pathway. This leakiness is characterized by a leakage permeability for the pathway, and recent work has sought to determine frequency distributions for the leakage permeabilities of wells and wellbores. We conduct a probabilistic analysis of leakage and monetized leakage risk for CO2 injection locations in the Michigan Sedimentary Basin (USA) using empirically derived frequency distributions for wellbore leakage permeabilities. To conduct this probabilistic risk analysis, we apply the RISCS (Risk Interference of Subsurface CO2 Storage) model (Bielicki et al, 2013a, 2012b) to injection into the Mt. Simon Sandstone. RISCS monetizes leakage risk

  12. CO2-Brine Rheology Could Suppress Leakage From Geologic Carbon Sequestration Sites

    NASA Astrophysics Data System (ADS)

    Wang, S.; Clarens, A. F.

    2011-12-01

    Geologic carbon sequestration (GCS) in the deep subsurface is an attractive means for storing large volumes of CO2 over the long term. GCS is predicated on there being minimal leakage of CO2 to the surface since this would negate the climate change benefits and could also create a human health risk. Despite the importance of understanding leakage processes to GCS deployment, the phenomena remain especially difficult to characterize because CO2, driven by buoyant forces out of host formations, must travel over long length scales, encountering varied geologic formations and endogenous brines, and experiencing a wide range of shear, temperature and pressure conditions that result in complex phase behavior. This study explores the rheology of CO2-brine mixtures in an effort to better characterize the geophysics of a rising parcel of CO2 in the subsurface. Experimental work in this area to date has assumed that CO2-brine mixtures will exhibit simple Newtonian behavior. The hypothesis of this work is that CO2-brine mixtures will move through porous media generating high shear rates, caused by the small pore sizes, that could result in more complex flow phenomena. The rheological properties of single and multiphase CO2-brine mixtures were measured over a range of GCS-relevant temperature, pressure, ionic strength, and shear conditions using a rotational rheometer fitted with a high-pressure vessel and a low viscosity measurement unit. Under liquid-liquid equilibrium (LLE) conditions CO2-brine mixtures were found to exhibit consistently Newtonian behavior with the effective viscosity generally increasing with respect to CO2(aq) concentration. A small dip in viscosity occurs at the pressure corresponding to the transition of CO2 from liquid to gas but this minor effect is not likely to have an appreciable impact on leakage rates. More significantly, under vapor-liquid equilibrium (VLE) conditions, CO2-brine suspensions exhibit complex viscoelastic behavior that could

  13. Roger Sperry and his chemoaffinity hypothesis.

    PubMed

    Meyer, R L

    1998-10-01

    In the early 1940s, Roger Sperry performed a series of insightful experiments on the visual system of lower vertebrates that led him to draw two important conclusions: When optic fibers were severed, the regenerating fibers grew back to their original loci in the midbrain tectum to re-establish a topographical set of connections; and the re-establishment of these orderly connections underlay the orderly behavior of the animal. From these conclusions, he inferred that each optic fiber and each tectal neuron possessed cytochemical labels that uniquely denoted their neuronal type and position and that optic fibers could utilize these labels to selectively navigate to their matching target cell. This inference was subsequently formulated into a general explanation of how neurons form ordered interconnections during development and became known as the chemoaffinity hypothesis. The origins of this hypothesis, the controversies that surrounded it for several decades and its eventual acceptance, are discussed in this article. PMID:9845045

  14. A hypothesis for delayed dynamic earthquake triggering

    USGS Publications Warehouse

    Parsons, T.

    2005-01-01

    It's uncertain whether more near-field earthquakes are triggered by static or dynamic stress changes. This ratio matters because static earthquake interactions are increasingly incorporated into probabilistic forecasts. Recent studies were unable to demonstrate all predictions from the static-stress-change hypothesis, particularly seismicity rate reductions. However, current dynamic stress change hypotheses do not explain delayed earthquake triggering and Omori's law. Here I show numerically that if seismic waves can alter some frictional contacts in neighboring fault zones, then dynamic triggering might cause delayed triggering and an Omori-law response. The hypothesis depends on faults following a rate/state friction law, and on seismic waves changing the mean critical slip distance (Dc) at nucleation zones.

  15. Exploring heterogeneous market hypothesis using realized volatility

    NASA Astrophysics Data System (ADS)

    Chin, Wen Cheong; Isa, Zaidi; Mohd Nor, Abu Hassan Shaari

    2013-04-01

    This study investigates the heterogeneous market hypothesis using high frequency data. The cascaded heterogeneous trading activities with different time durations are modelled by the heterogeneous autoregressive framework. The empirical study indicated the presence of long memory behaviour and predictability elements in the financial time series which supported heterogeneous market hypothesis. Besides the common sum-of-square intraday realized volatility, we also advocated two power variation realized volatilities in forecast evaluation and risk measurement in order to overcome the possible abrupt jumps during the credit crisis. Finally, the empirical results are used in determining the market risk using the value-at-risk approach. The findings of this study have implications for informationally market efficiency analysis, portfolio strategies and risk managements.

  16. Geochemical confirmation of the lunar magmasphere hypothesis

    NASA Technical Reports Server (NTRS)

    Warren, P. H.

    1985-01-01

    The lunar magmasphere (or magma ocean) hypothesis was originally conceived to account for the enrichment of cumulus plagioclase (Al and Ca) in the main (highlands) portion of the crust. The great age of the highlands, and the complementary pattern of Eu anomalies between the highlands and the younger mare basalts, helped convince most specialists that the magmasphere hypothesis is correct. Doubts persist, however, particularly among physicists concerned about heat sources. It was shown in 1976 that a plot of Na/Ca vs. Mg/Fe for pristine highlands cumulates manifests a profound bimodality: One group, the Mg-rich rocks, plots along a normal igneous trend of inverse correlation between Na/Ca and Mg/Fe; the other group, the ferroan anorthosites (FAN), features low Na/Ca and low Mg/Fe. Only the FAN group can be plausibly linked to plag. flotation over the magmasphere.

  17. Hypothesis: microtubules, a key to Alzheimer disease.

    PubMed Central

    Matsuyama, S S; Jarvik, L F

    1989-01-01

    Alzheimer disease (AD) is a clinicopathologic syndrome of unknown etiology with numerous abnormalities in neuronal and nonneuronal cells. A review of the literature suggests that a common basic intracellular defect may underlie many of the reported abnormalities. We hypothesize impairment of the microtubule (MT) system as one explanation for the pathogenesis of AD. Evidence in support of the hypothesis includes the following: MTs are ubiquitous and vital cell components, unequally distributed, with the highest concentration in the brain; various abnormalities, including the key neuropathologic lesions, can be explained by impairments of the MT system; and experiments utilizing pharmacologic agents known to disrupt MTs have reproduced certain abnormalities observed in AD. The hypothesis provides a framework for systematic investigations of MTs at the cellular and molecular levels as well as the basis for in vivo diagnostic tests for AD. PMID:2813384

  18. Roger Sperry and his chemoaffinity hypothesis.

    PubMed

    Meyer, R L

    1998-10-01

    In the early 1940s, Roger Sperry performed a series of insightful experiments on the visual system of lower vertebrates that led him to draw two important conclusions: When optic fibers were severed, the regenerating fibers grew back to their original loci in the midbrain tectum to re-establish a topographical set of connections; and the re-establishment of these orderly connections underlay the orderly behavior of the animal. From these conclusions, he inferred that each optic fiber and each tectal neuron possessed cytochemical labels that uniquely denoted their neuronal type and position and that optic fibers could utilize these labels to selectively navigate to their matching target cell. This inference was subsequently formulated into a general explanation of how neurons form ordered interconnections during development and became known as the chemoaffinity hypothesis. The origins of this hypothesis, the controversies that surrounded it for several decades and its eventual acceptance, are discussed in this article.

  19. Tests of the Giant Impact Hypothesis

    NASA Technical Reports Server (NTRS)

    Jones, J. H.

    1998-01-01

    The giant impact hypothesis has gained popularity as a means of explaining a volatile-depleted Moon that still has a chemical affinity to the Earth. As Taylor's Axiom decrees, the best models of lunar origin are testable, but this is difficult with the giant impact model. The energy associated with the impact would be sufficient to totally melt and partially vaporize the Earth. And this means that there should he no geological vestige of Barber times. Accordingly, it is important to devise tests that may be used to evaluate the giant impact hypothesis. Three such tests are discussed here. None of these is supportive of the giant impact model, but neither do they disprove it.

  20. The Neural Rejuvenation Hypothesis of Cocaine Addiction

    PubMed Central

    Dong, Yan; Nestler, Eric J.

    2014-01-01

    A leading hypothesis guiding current molecular and cellular research of drug addiction conceptualizes key aspects of addiction as a form of memory, in which common neuroplasticity mechanisms that mediate normal learning and memory processes are “hijacked” by exposure to drugs of abuse to produce pathologic addiction-related memories. Such addiction-related memories are particularly robust and long-lasting and once formed, less amenable to updating. Here, we propose the Neural Rejuvenation Hypothesis of Cocaine Addiction: that repeated exposure to drugs of abuse induces some plasticity mechanisms that are normally associated with brain development within the brain’s reward circuitry, which mediate the highly efficient and unusually stable memory abnormalities that characterize addiction. PMID:24958329

  1. Kelvin on an old, celebrated hypothesis

    NASA Astrophysics Data System (ADS)

    Harrison, Edward

    1986-07-01

    Lord Kelvin in 1901 tested an ``old and celebrated hypothesis'' that if we could see far enough into space the whole sky would be occupied with stellar disks all of perhaps the same brightness as the Sun. Kelvin was the first to solve quantitatively and correctly the riddle of a dark night sky, a riddle that had been previously solved qualitatively by Edgar Allan Poe, and is now known as Olbers' paradox.

  2. Sea otter health: challenging a pet hypothesis

    USGS Publications Warehouse

    Lafferty, Kevin D.

    2015-01-01

    A recent series of studies on tagged sea otters (Enhydra lutris nereis) challenges the hypothesis that sea otters are sentinels of a dirty ocean, in particular, that pet cats are the main source of exposure to Toxoplasma gondii in central California. Counter to expectations, sea otters from unpopulated stretches of coastline are less healthy and more exposed to parasites than city-associated otters. Ironically, now it seems that spillover from wildlife, not pets, dominates spatial patterns of disease transmission.

  3. Moon origin - The impact-trigger hypothesis

    NASA Technical Reports Server (NTRS)

    Hartmann, William K.

    1986-01-01

    Arguments in favor of the impact-trigger model of lunar origin are presented. Lunar properties favoring this hypothesis include: (1) lunar iron and volatile deficiency; (2) angular momentum of the earth-moon system; and (3) similar O isotopes, bulk iron contents, and densities of earth's mantle and the moon. It is shown that the intense early bombardment averaged during earth's formation was several billion times the present meteoritic mass flux, consistent with a giant impact.

  4. Sea otter health: Challenging a pet hypothesis

    PubMed Central

    Lafferty, Kevin D.

    2015-01-01

    A recent series of studies on tagged sea otters (Enhydra lutris nereis) challenges the hypothesis that sea otters are sentinels of a dirty ocean, in particular, that pet cats are the main source of exposure to Toxoplasma gondii in central California. Counter to expectations, sea otters from unpopulated stretches of coastline are less healthy and more exposed to parasites than city-associated otters. Ironically, now it seems that spillover from wildlife, not pets, dominates spatial patterns of disease transmission. PMID:26155464

  5. An impact hypothesis for Venus argon anomalies

    NASA Astrophysics Data System (ADS)

    Kaula, W. M.; Newman, W. I.

    1997-03-01

    The Ar-36+38 argon-excess anomally of Venus has been hypothesized to have its origin in the impact of an outer solar system body of about 100-km diameter. A critical evaluation is made of this hypothesis and its competitors; it is judged that its status must for the time being remain one of 'Sherlock Holmes' type, in that something so improbable must be accepted when all alternatives are eliminated.

  6. Sea otter health: Challenging a pet hypothesis.

    PubMed

    Lafferty, Kevin D

    2015-12-01

    A recent series of studies on tagged sea otters (Enhydra lutris nereis) challenges the hypothesis that sea otters are sentinels of a dirty ocean, in particular, that pet cats are the main source of exposure to Toxoplasma gondii in central California. Counter to expectations, sea otters from unpopulated stretches of coastline are less healthy and more exposed to parasites than city-associated otters. Ironically, now it seems that spillover from wildlife, not pets, dominates spatial patterns of disease transmission. PMID:26155464

  7. Testing the single-state dominance hypothesis

    SciTech Connect

    Álvarez-Rodríguez, R.; Moreno, O.; Moya de Guerra, E.; Sarriguren, P.; Šimkovic, F.; Faessler, A.

    2013-12-30

    We present a theoretical analysis of the single-state dominance hypothesis for the two-neutrino double-beta decay process. The theoretical framework is a proton-neutron QRPA based on a deformed Hartree-Fock mean field with BCS pairing correlations. We focus on the decays of {sup 100}Mo, {sup 116}Cd and {sup 128}Te. We do not find clear evidences for single-state dominance within the present approach.

  8. The spline probability hypothesis density filter

    NASA Astrophysics Data System (ADS)

    Sithiravel, Rajiv; Tharmarasa, Ratnasingham; McDonald, Mike; Pelletier, Michel; Kirubarajan, Thiagalingam

    2012-06-01

    The Probability Hypothesis Density Filter (PHD) is a multitarget tracker for recursively estimating the number of targets and their state vectors from a set of observations. The PHD filter is capable of working well in scenarios with false alarms and missed detections. Two distinct PHD filter implementations are available in the literature: the Sequential Monte Carlo Probability Hypothesis Density (SMC-PHD) and the Gaussian Mixture Probability Hypothesis Density (GM-PHD) filters. The SMC-PHD filter uses particles to provide target state estimates, which can lead to a high computational load, whereas the GM-PHD filter does not use particles, but restricts to linear Gaussian mixture models. The SMC-PHD filter technique provides only weighted samples at discrete points in the state space instead of a continuous estimate of the probability density function of the system state and thus suffers from the well-known degeneracy problem. This paper proposes a B-Spline based Probability Hypothesis Density (S-PHD) filter, which has the capability to model any arbitrary probability density function. The resulting algorithm can handle linear, non-linear, Gaussian, and non-Gaussian models and the S-PHD filter can also provide continuous estimates of the probability density function of the system state. In addition, by moving the knots dynamically, the S-PHD filter ensures that the splines cover only the region where the probability of the system state is significant, hence the high efficiency of the S-PHD filter is maintained at all times. Also, unlike the SMC-PHD filter, the S-PHD filter is immune to the degeneracy problem due to its continuous nature. The S-PHD filter derivations and simulations are provided in this paper.

  9. Temperature and leakage aware techniques to improve cache reliability

    NASA Astrophysics Data System (ADS)

    Akaaboune, Adil

    Decreasing power consumption in small devices such as handhelds, cell phones and high-performance processors is now one of the most critical design concerns. On-chip cache memories dominate the chip area in microprocessors and thus arises the need for power efficient cache memories. Cache is the simplest cost effective method to attain high speed memory hierarchy and, its performance is extremely critical for high speed computers. Cache is used by the microprocessor for channeling the performance gap between processor and main memory (RAM) hence the memory bandwidth is frequently a bottleneck which can affect the peak throughput significantly. In the design of any cache system, the tradeoffs of area/cost, performance, power consumption, and thermal management must be taken into consideration. Previous work has mainly concentrated on performance and area/cost constraints. More recent works have focused on low power design especially for portable devices and media-processing systems, however fewer research has been done on the relationship between heat management, Leakage power and cost per die. Lately, the focus of power dissipation in the new generations of microprocessors has shifted from dynamic power to idle power, a previously underestimated form of power loss that causes battery charge to drain and shutdown too early due the waste of energy. The problem has been aggravated by the aggressive scaling of process; device level method used originally by designers to enhance performance, conserve dissipation and reduces the sizes of digital circuits that are increasingly condensed. This dissertation studies the impact of hotspots, in the cache memory, on leakage consumption and microprocessor reliability and durability. The work will first prove that by eliminating hotspots in the cache memory, leakage power will be reduced and therefore, the reliability will be improved. The second technique studied is data quality management that improves the quality of the data

  10. Paleoindian demography and the extraterrestrial impact hypothesis

    PubMed Central

    Buchanan, Briggs; Collard, Mark; Edinborough, Kevan

    2008-01-01

    Recently it has been suggested that one or more large extraterrestrial (ET) objects struck northern North America 12,900 ± 100 calendar years before present (calBP) [Firestone RB, et al. (2007) Proc Natl Acad Sci USA 104: 16016–16021]. This impact is claimed to have triggered the Younger Dryas major cooling event and resulted in the extinction of the North American megafauna. The impact is also claimed to have caused major cultural changes and population decline among the Paleoindians. Here, we report a study in which ≈1,500 radiocarbon dates from archaeological sites in Canada and the United States were used to test the hypothesis that the ET resulted in population decline among the Paleoindians. Following recent studies [e.g., Gamble C, Davies W, Pettitt P, Hazelwood L, Richards M (2005) Camb Archaeol J 15:193–223), the summed probability distribution of the calibrated dates was used to identify probable changes in human population size between 15,000 and 9,000 calBP. Subsequently, potential biases were evaluated by modeling and spatial analysis of the dated occupations. The results of the analyses were not consistent with the predictions of extraterrestrial impact hypothesis. No evidence of a population decline among the Paleoindians at 12,900 ± 100 calBP was found. Thus, minimally, the study suggests the extraterrestrial impact hypothesis should be amended. PMID:18697936

  11. Air Leakage and Air Transfer Between Garage and Living Space

    SciTech Connect

    Rudd, A.

    2014-09-01

    This research project focused on evaluation of air transfer between the garage and living space in a single-family detached home constructed by a production homebuilder in compliance with the 2009 International Residential Code and the 2009 International Energy Conservation Code. The project gathered important information about the performance of whole-building ventilation systems and garage ventilation systems as they relate to minimizing flow of contaminated air from garage to living space. A series of 25 multi-point fan pressurization tests and additional zone pressure diagnostic testing characterized the garage and house air leakage, the garage-to-house air leakage, and garage and house pressure relationships to each other and to outdoors using automated fan pressurization and pressure monitoring techniques. While the relative characteristics of this house may not represent the entire population of new construction configurations and air tightness levels (house and garage) throughout the country, the technical approach was conservative and should reasonably extend the usefulness of the results to a large spectrum of house configurations from this set of parametric tests in this one house. Based on the results of this testing, the two-step garage-to-house air leakage test protocol described above is recommended where whole-house exhaust ventilation is employed. For houses employing whole-house supply ventilation (positive pressure) or balanced ventilation (same pressure effect as the Baseline condition), adherence to the EPA Indoor airPLUS house-to-garage air sealing requirements should be sufficient to expect little to no garage-to-house air transfer.

  12. Power Beaming Leakage Radiation as a SETI Observable

    NASA Astrophysics Data System (ADS)

    Benford, James N.; Benford, Dominic J.

    2016-07-01

    The most observable leakage radiation from an advanced civilization may well be from the use of power beaming to transfer energy and accelerate spacecraft. Applications suggested for power beaming involve launching spacecraft to orbit, raising satellites to a higher orbit, and interplanetary concepts involving space-to-space transfers of cargo or passengers. We also quantify beam-driven launch to the outer solar system, interstellar precursors, and ultimately starships. We estimate the principal observable parameters of power beaming leakage. Extraterrestrial civilizations would know their power beams could be observed, and so could put a message on the power beam and broadcast it for our receipt at little additional energy or cost. By observing leakage from power beams we may find a message embedded on the beam. Recent observations of the anomalous star KIC 8462852 by the Allen Telescope Array (ATA) set some limits on extraterrestrial power beaming in that system. We show that most power beaming applications commensurate with those suggested for our solar system would be detectable if using the frequency range monitored by the ATA, and so the lack of detection is a meaningful, if modest, constraint on extraterrestrial power beaming in that system. Until more extensive observations are made, the limited observation time and frequency coverage are not sufficiently broad in frequency and duration to produce firm conclusions. Such beams would be visible over large interstellar distances. This implies a new approach to the SETI search: instead of focusing on narrowband beacon transmissions generated by another civilization, look for more powerful beams with much wider bandwidth. This requires a new approach for their discovery by telescopes on Earth. Further studies of power beaming applications should be performed, potentially broadening the parameter space of the observable features that we have discussed here.

  13. Leakage of decision uncertainty into movement execution in Parkinson's disease?

    PubMed

    Praamstra, Peter; Loing, Andrea F; de Lange, Floris P

    2014-01-01

    The concept of segregated basal ganglia-cortical loops entails that functional disturbances may result from abnormal processing within loops, but also from abnormal communication between loops. Cognitive and motor processes subserved by different basal ganglia-frontal loops may interfere with one another as a result of such abnormal communication, leakage, between loops. In Parkinson's disease, movement execution has been found susceptible to decision uncertainty, attributed to this mechanism. Here, we evaluate whether this mechanism of abnormal coupling or leakage extends to perceptual decision-making with trial-by-trial control of decision uncertainty. We examined 10 Parkinson's disease (PD) patients and healthy control subjects in a random-dot motion direction discrimination task with concurrent EEG recording. Random-dot motion was manipulated to make direction discrimination easy or difficult. Reaction times (RT) and movement times (MT) were recorded, and EEG was analysed to extract movement-related potentials. Easy versus difficult direction discrimination produced robust, equally large RT differences in patients and controls (>400 ms), along with a marked difference in error rates, confirming the efficacy of the task. Effects of easy versus difficult discrimination on MT were comparatively small (<50 ms) and did not differ between groups, despite robustly slower MT in patients. Lateralised movement-related EEG potentials reproduced the MT difference between patients and controls. Together, the results do not demonstrate an enhanced effect of decision uncertainty onto movement execution in PD. We surmise that leakage of decision uncertainty into movement execution is probably task-dependent, consistent with the view that the degree to which partial information is allowed to influence the motor system is under strategic control. PMID:24091773

  14. [Diagnosis of cerebrospinal fluid leakages by gamma-cisternography].

    PubMed

    Oberson, R

    1976-01-01

    Cerebrospinal fluid (CSF) leakages either secondary (traumatic) or spontaneous (non-traumatic) are first considered in their frequency and origin. The exact topography of the various meningeal and cranial lesions involved are difficult to assess particularly in the most important groups of persistant traumatic CSF rhinorrhea and recurrent meningitis. Among the various diagnostic approaches, direct observation is always necessary, but of limited value. Standard X-rays must be followed by multidirectionnal tomography (Polytome) and, whenever available, computed tomodensitography of the base of the skull. Brain pneumography provides a thorough setting fourth of the congenital or acquired cerebral lesions as well as the new cranio-meningeal conditions. Difficulties encountered with the techniques of subdurography and Pantopaque injection are underlined. Three radioisotope techniques are considered. 1) The earlier technique of cotton-pledgets only shows the external orifice. 2) The recent proposal of nuclide cranial subdurography is criticized for ignoring the leptomeningeal bag. 3) Radioisotope cisternography (RIC) or gamma-cisternography is described more precisely. It remains the most complete and appropriate method for observing the natural behaviour of the leakage. RIC with fistulography is performed through suboccipital injection of 99mTc-DTPA. RIC provides essential clues on the relative importance of associated dynamic disturbances of the third circulation and morphological changes of its anatomical bed (stenoses and widenings of the ependymal and leptomeningeal spaces). If present, the leakage may be directly shown on the RIC pictures. If rhinorrhea is abundant, there is no difficulty in assessing side and site of the fistula. If rhinorrhea is occult, dubious or intermittent, diagnosis is often difficult. There are also indirect signs of rhinorrhea: leptomeningeal dilatation near a frontal or ethmoidal fracture, contamination of the rhinopharynx, examination of

  15. Impeller leakage flow modeling for mechanical vibration control

    NASA Technical Reports Server (NTRS)

    Palazzolo, Alan B.

    1996-01-01

    HPOTP and HPFTP vibration test results have exhibited transient and steady characteristics which may be due to impeller leakage path (ILP) related forces. For example, an axial shift in the rotor could suddenly change the ILP clearances and lengths yielding dynamic coefficient and subsequent vibration changes. ILP models are more complicated than conventional-single component-annular seal models due to their radial flow component (coriolis and centrifugal acceleration), complex geometry (axial/radial clearance coupling), internal boundary (transition) flow conditions between mechanical components along the ILP and longer length, requiring moment as well as force coefficients. Flow coupling between mechanical components results from mass and energy conservation applied at their interfaces. Typical components along the ILP include an inlet seal, curved shroud, and an exit seal, which may be a stepped labyrinth type. Von Pragenau (MSFC) has modeled labyrinth seals as a series of plain annular seals for leakage and dynamic coefficient prediction. These multi-tooth components increase the total number of 'flow coupled' components in the ILP. Childs developed an analysis for an ILP consisting of a single, constant clearance shroud with an exit seal represented by a lumped flow-loss coefficient. This same geometry was later extended to include compressible flow. The objective of the current work is to: supply ILP leakage-force impedance-dynamic coefficient modeling software to MSFC engineers, base on incompressible/compressible bulk flow theory; design the software to model a generic geometry ILP described by a series of components lying along an arbitrarily directed path; validate the software by comparison to available test data, CFD and bulk models; and develop a hybrid CFD-bulk flow model of an ILP to improve modeling accuracy within practical run time constraints.

  16. Appropriate sampling for intracellular amino acid analysis in five phylogenetically different yeasts.

    PubMed

    Bolten, Christoph J; Wittmann, Christoph

    2008-11-01

    Methanol quenching and fast filtration, the two most common sampling protocols in microbial metabolome analysis, were validated for intracellular amino acid analysis in phylogenetically different yeast strains comprising Saccharomyces cerevisiae, Kluyveromyces marxianus, Pichia pastoris, Schizosaccharomyces pombe and Zygosaccharomyces bailii. With only few exceptions for selected amino acids, all yeasts exhibited negligible metabolite leakage during quenching with 60% cold buffered methanol. Slightly higher leakage was observed with increasing methanol content in the quenching solution. Fast filtration resulted in identical levels for intracellular amino acids in all strains tested. The results clearly demonstrate the validity of both approaches for leakage-free sampling of amino acids in yeast.

  17. Magnetic mechanisms of magnetic flux leakage nondestructive testing

    NASA Astrophysics Data System (ADS)

    Sun, Yanhua; Kang, Yihua

    2013-10-01

    The widely applied magnetic flux leakage (MFL) nondestructive testing for ferrous materials has been simply explained by "MFL escaping from defects and being induced is exactly the MFL testing principle," with a rough application for evaluation. Hence, we analyze the "escape" course of MFL generation using magnetic refraction and explain the reason why the MFL technology really exists in practice. Furthermore, we also point out that the presently so-called MFL testing technique essentially hides a different signal component arising from bump-shaped defects features unlike the MFL caused by concave-shaped ones, explained by another forming mechanism.

  18. Numerical Simulations of Leakage from Underground LPG Storage Caverns

    SciTech Connect

    Yamamoto, Hajime; Pruess, Karsten

    2004-09-01

    To secure a stable supply of petroleum gas, underground storage caverns for liquified petroleum gas (LPG) are commonly used in many countries worldwide. Storing LPG in underground caverns requires that the surrounding rock mass remain saturated with groundwater and that the water pressure be higher than the liquid pressure inside the cavern. In previous studies, gas containment criteria for underground gas storage based on hydraulic gradient and pressure have been discussed, but these studies do not consider the physicochemical characteristics and behavior of LPG such as vaporization and dissolution in groundwater. Therefore, while these studies are very useful for designing storage caverns, they do not provide better understanding of the either the environmental effects of gas contamination or the behavior of vaporized LPG. In this study, we have performed three-phase fluid flow simulations of gas leakage from underground LPG storage caverns, using the multiphase multicomponent nonisothermal simulator TMVOC (Pruess and Battistelli, 2002), which is capable of solving the three-phase nonisothermal flow of water, gas, and a multicomponent mixture of volatile organic chemicals (VOCs) in multidimensional heterogeneous porous media. A two-dimensional cross-sectional model resembling an actual underground LPG facility in Japan was developed, and gas leakage phenomena were simulated for three different permeability models: (1) a homogeneous model, (2) a single-fault model, and (3) a heterogeneous model. In addition, the behavior of stored LPG was studied for the special case of a water curtain suddenly losing its function because of operational problems, or because of long-term effects such as clogging of boreholes. The results of the study indicate the following: (1) The water curtain system is a very powerful means for preventing gas leakage from underground storage facilities. By operating with appropriate pressure and layout, gas containment can be ensured. (2

  19. Pharmacological effects of various venoms on cutaneous capillary leakage.

    PubMed

    Burnett, J W; Calton, G J

    1986-01-01

    Studies to counteract the cutaneous vasopermeability actions of a wasp (Vespa orientalis), an anemone (Bolocera tuediae) and three jellyfish (Chironex fleckeri, Chrysaora quinquecirrha and Physalia physalis) venoms were conducted by using various pharmacological antagonists. Piripost (a leukotriene inhibitor) reduced vasopermeability if administered 5 min prior to challenge with the jellyfish venoms. Methysergide counteracted the vasopermeability of three of four coelenterate venoms, whereas indomethacin was effective against capillary leakage induced by Chironex venom. These studies indicate that anti-dermonecrotic therapy against various venoms will have to be species-specific. PMID:2875548

  20. Effects of brush seal morphology on leakage and pressure drops

    NASA Technical Reports Server (NTRS)

    Braun, M. J.; Yang, Y.; Hendricks, R. C.

    1991-01-01

    Research on brush seals which was undertaken earlier by Braun et al. (1990) is continued. Particular attention is given to the effects of brush positioning, design, and morphology on sealing surfaces, fluid leakage, and associated pressure drops. It is found that both the structure and the design of the brush are important to its performance. High resistance to the flow of the brush/fence combination can result in catastrophic failure of the brush, while at lower flow resistances, the failure is more gradual.

  1. A novel method to determine air leakage in heat pump clothes dryers

    DOE PAGES

    Bansal, Pradeep; Mohabir, Amar; Miller, William

    2016-01-06

    A heat pump clothes dryer offers the potential to save a significant amount of energy as compared with conventional vented electric dryers. Although heat pump clothes dryers (HPCD) offer higher energy efficiency; it has been observed that they are prone to air leakages, which inhibits the HPCD's gain in efficiency. This study serves to develop a novel method of quantifying leakage, and to determine specific leakage locations in the dryer drum and air circulation system. The basis of this method is the American Society of Testing and Materials (ASTM) standard E779 10, which is used to determine air leakage areamore » in a household ventilation system through fan pressurization. This ASTM method is adapted to the dryer system, and the leakage area is determined by an analysis of the leakage volumetric flow - pressure relationship. Easily accessible leakage points were quantified: the front and back crease (in the dryer drum), the leakage in the dryer duct, the air filter, and the remaining leakage in the drum. The procedure allows investigators to determine major components contributing to leakage in HPCDs, thus improving component design features that result in more efficient HPCD systems.« less

  2. A NOVEL METHOD TO DETERMINE AIR LEAKAGE IN HEAT PUMP CLOTHES DRYERS

    SciTech Connect

    Bansal, Pradeep; Miller, William A

    2016-01-01

    A heat pump clothes dryer offers the potential to save a significant amount of energy as compared with conventional vented electric dryers. Although heat pump clothes dryers (HPCD) offer higher energy efficiency; it has been observed that they are prone to air leakages, which inhibits the HPCD's gain in efficiency. This study serves to develop a novel method of quantifying leakage, and to determine specific leakage locations in the dryer drum and air circulation system. The basis of this method is the American Society of Testing and Materials (ASTM) standard E779 10, which is used to determine air leakage area in a household ventilation system through fan pressurization. This ASTM method is adapted to the dryer system, and the leakage area is determined by an analysis of the leakage volumetric flow - pressure relationship. Easily accessible leakage points were quantified: the front and back crease (in the dryer drum), the leakage in the dryer duct, the air filter, and the remaining leakage in the drum. The procedure allows investigators to determine major components contributing to leakage in HPCDs, thus improving component design features that result in more efficient HPCD systems.

  3. Origin of Translation - the Hypothesis of Permanently Attached Adaptors

    NASA Astrophysics Data System (ADS)

    Tyagi, Sanjay

    1981-12-01

    A mechanism for prebiotic translation is proposed in which primeval transfer-RNA (adaptors) are assumed to be permanently associated with messenger nucleic acid molecules. Residual ‘fossil’ evidences are found to be present within the base sequences of contemporary tRNAs, suggesting the existence of inter-primal-tRNA interactions necessary for the mechanism. The structure of proposed primal-tRNA is such that it can not only choose its own amino acid in the absence of aminoacyl synthetase, but can also associate nonspecifically with adjacent primal-tRNA molecules attached to the neighbouring codons. Such associations can give rise, through cooperative binding between message and adaptors to the ‘static template surfaces’ which can direct translation of nucleotide sequences into those of amino acids. The origins of ribosomes and contemporary genetic code are suggested by this hypothesis. Proposed structures and processes are thermodynamically compatible. The approximate date of occurence of the proposed system is calculated, which is consistent with the period of occurence of the earliest organisms with ribosomes.

  4. Low standby leakage 12T SRAM cell characterisation

    NASA Astrophysics Data System (ADS)

    Yadav, Arjun; Nakhate, Sangeeta

    2016-09-01

    In this work, a low power and variability-aware static random access memory (SRAM) architecture based on a twelve-transistor (12T) cell is proposed. This cell obtains low static power dissipation due to a parallel global latch (G-latch) and storage latch (S-latch), along with a global wordline (GWL), which offer a high cell ratio and pull-up ratio for reliable read and write operations and a low cell ratio and pull-up ratio during idle mode to reduce the standby power dissipation. In the idle state, only the S-latch stores bits, while the G-latch is isolated from the S-latch and the GWL is deactivated. The leakage power consumption of the proposed SRAM cell is thereby reduced by 38.7% compared to that of the conventional six-transistor (6T) SRAM cell. This paper evaluates the impact of the chip supply voltage and surrounding temperature variations on the standby leakage power and observes considerable improvement in the power dissipation. The read/write access delay, read static noise margin (SNM) and write SNM were evaluated, and the results were compared with those of the standard 6T SRAM cell. The proposed cell, when compared with the existing cell using the Monte Carlo method, shows an appreciable improvement in the standby power dissipation and layout area.

  5. An Advanced Leakage Scheme for Neutrino Treatment in Astrophysical Simulations

    NASA Astrophysics Data System (ADS)

    Perego, A.; Cabezón, R. M.; Käppeli, R.

    2016-04-01

    We present an Advanced Spectral Leakage (ASL) scheme to model neutrinos in the context of core-collapse supernovae (CCSNe) and compact binary mergers. Based on previous gray leakage schemes, the ASL scheme computes the neutrino cooling rates by interpolating local production and diffusion rates (relevant in optically thin and thick regimes, respectively) separately for discretized values of the neutrino energy. Neutrino trapped components are also modeled, based on equilibrium and timescale arguments. The better accuracy achieved by the spectral treatment allows a more reliable computation of neutrino heating rates in optically thin conditions. The scheme has been calibrated and tested against Boltzmann transport in the context of Newtonian spherically symmetric models of CCSNe. ASL shows a very good qualitative and a partial quantitative agreement for key quantities from collapse to a few hundreds of milliseconds after core bounce. We have proved the adaptability and flexibility of our ASL scheme, coupling it to an axisymmetric Eulerian and to a three-dimensional smoothed particle hydrodynamics code to simulate core collapse. Therefore, the neutrino treatment presented here is ideal for large parameter-space explorations, parametric studies, high-resolution tests, code developments, and long-term modeling of asymmetric configurations, where more detailed neutrino treatments are not available or are currently computationally too expensive.

  6. Variable cycle stirling engine and gas leakage control system therefor

    SciTech Connect

    Otters, J.

    1984-12-25

    An improved thermal engine of the type having a displacer body movable between the hot end and the cold end of a chamber for subjecting a fluid within that chamber to a thermodynamic cycle and having a work piston driven by the fluid for deriving a useful work output. The work piston pumps a hydraulic fluid and a hydraulic control valve is connected in line with the hydraulic output conduit such that the flow of hydraulic fluid may be restricted to any desired degree or stopped altogether. The work piston can therefore be controlled by means of a controller device independently from the movement of the displacer such that a variety of engine cycles can be obtained for optimum engine efficiency under varying load conditions. While a Stirling engine cycle is particularly contemplated, other engine cycles may be obtained by controlling the movement of the displacer and work pistons. Also disclosed are a working gas recovery system for controlling leakage of working gas from the displacer chamber, and a compound work piston arrangement for preventing leakage of hydraulic fluid around the work piston into the displacer chamber.

  7. Effect of masticatory cycles on apical leakage of obturated teeth.

    PubMed

    Esber, S; Blum, J Y; Chazel, J C; Parahy, E

    1998-05-01

    This study investigated the effect of apical leakage due to masticatory cycles on root canal treatment. Twenty upper maxillary molars were first obturated using the warm vertical compaction technique. Four maxillary casts were then built, with each holding four of the sample molars. The molars were embedded in resin with the roots separated from the resin by means of a light silicon. The four remaining teeth served as controls and were not submitted to occlusal forces. A mechanical device to simulate masticatory cycles subjected the teeth to 0.5 x 10(6) cycles (group A), 10(6) cycles (group B), 2 x 10(6) cycles (group C), and 3 x 10(6) cycles (group D); the control was group E. The roots were placed in 2% methylene blue dye solution for 72 h and then sectioned longitudinally so that dye penetration could be measured. The mean values of dye penetration were: 3.70 +/- 0.69 mm, group A; 5.00 +/- 1.14 mm, group B; 6.00 +/- 1.01 mm, group C; 7.23 +/- 0.66 mm, group D; and 2.74 +/- 0.75 mm, group E. The value of dye penetration increased in correlation with the number of masticatory cycles. This in vitro study suggests the significant effect of masticatory loads on apical leakage. PMID:9641106

  8. Greater focus needed on methane leakage from natural gas infrastructure.

    PubMed

    Alvarez, Ramón A; Pacala, Stephen W; Winebrake, James J; Chameides, William L; Hamburg, Steven P

    2012-04-24

    Natural gas is seen by many as the future of American energy: a fuel that can provide energy independence and reduce greenhouse gas emissions in the process. However, there has also been confusion about the climate implications of increased use of natural gas for electric power and transportation. We propose and illustrate the use of technology warming potentials as a robust and transparent way to compare the cumulative radiative forcing created by alternative technologies fueled by natural gas and oil or coal by using the best available estimates of greenhouse gas emissions from each fuel cycle (i.e., production, transportation and use). We find that a shift to compressed natural gas vehicles from gasoline or diesel vehicles leads to greater radiative forcing of the climate for 80 or 280 yr, respectively, before beginning to produce benefits. Compressed natural gas vehicles could produce climate benefits on all time frames if the well-to-wheels CH(4) leakage were capped at a level 45-70% below current estimates. By contrast, using natural gas instead of coal for electric power plants can reduce radiative forcing immediately, and reducing CH(4) losses from the production and transportation of natural gas would produce even greater benefits. There is a need for the natural gas industry and science community to help obtain better emissions data and for increased efforts to reduce methane leakage in order to minimize the climate footprint of natural gas. PMID:22493226

  9. Development of monitoring system of helium leakage from canister

    SciTech Connect

    Toriu, D.; Ushijima, S.; Takeda, H.

    2013-07-01

    This paper presents a computational method for the helium leakage from a canister. The governing equations for compressible fluids consist of mass conservation equation in Eulerian description, momentum equations and energy equation. The numerical procedures are divided into three phases, advection, diffusion and acoustic phases, and the equations of compressible fluids are discretized with a finite volume method. Thus, the mass conservation law is sufficiently satisfied in the calculation region. In particular, our computational method enables us to predict the change of the temperature distributions around the canister boundaries by calculating the governing equations for the compressible gas flows, which are leaked out from a slight crack on the canister boundary. In order to confirm the validity of our method, it was applied to the basic problem, 2-dimensional natural convection flows in a rectangular cavity. As a result, it was shown that the naturally convected flows can be reasonably simulated by our method. Furthermore, numerical experiments were conducted for the helium leakage from canister and we derived a close relationship between the inner pressure and the boundary temperature distributions.

  10. Angiopoietin-2 is critical for cytokine-induced vascular leakage.

    PubMed

    Benest, Andrew V; Kruse, Karoline; Savant, Soniya; Thomas, Markus; Laib, Anna M; Loos, Elias K; Fiedler, Ulrike; Augustin, Hellmut G

    2013-01-01

    Genetic experiments (loss-of-function and gain-of-function) have established the role of Angiopoietin/Tie ligand/receptor tyrosine kinase system as a regulator of vessel maturation and quiescence. Angiopoietin-2 (Ang-2) acts on Tie2-expressing resting endothelial cells as an antagonistic ligand to negatively interfere with the vessel stabilizing effects of constitutive Ang-1/Tie-2 signaling. Ang-2 thereby controls the vascular response to inflammation-inducing as well as angiogenesis-inducing cytokines. This study was aimed at assessing the role of Ang-2 as an autocrine (i.e. endothelial-derived) regulator of rapid vascular responses (within minutes) caused by permeability-inducing agents. Employing two independent in vivo assays to quantitatively assess vascular leakage (tracheal microsphere assay, 1-5 min and Miles assay, 20 min), the immediate vascular response to histamine, bradykinin and VEGF was analyzed in Ang-2-deficient (Ang-2(-/-)) mice. In comparison to the wild type control mice, the Ang2(-/-) mice demonstrated a significantly attenuated response. The Ang-2(-/-) phenotype was rescued by systemic administration (paracrine) of an adenovirus encoding Ang-2. Furthermore, cytokine-induced intracellular calcium influx was impaired in Ang-2(-/-) endothelioma cells, consistent with reduced phospholipase activation in vivo. Additionally, recombinant human Ang-2 (rhAng-2) alone was unable to induce vascular leakage. In summary, we report here in a definite genetic setting that Ang-2 is critical for multiple vascular permeability-inducing cytokines. PMID:23940579

  11. Leakage predictions for Rayleigh-step, helium-purge seals

    NASA Technical Reports Server (NTRS)

    Proctor, Margaret P.

    1988-01-01

    Rayleigh-step, helium purge, annular shaft seals, studied for use in liquid oxygen turbopumps, generate a hydrodynamic force that enables the seal to follow shaft perturbations. Hence, smaller clearances can be used to reduce seal leakage. FLOWCAL, a computer code developed by Mechanical Technology Incorporated, predicts gas flow rate through an annular seal with an axial pressure gradient. Analysis of a 50-mm Rayleigh-step, helium-purge, annular seal showed the flow rate increased axial pressure gradient, downstream pressure, and eccentricity ratio. Increased inlet temperature reduced leakage. Predictions made at maximum and minimum clearances (due to centrifugal and thermal growths, machining tolerances and + or - 2 percent uncertainty in the clearance measurement) placed wide boundaries on expected flow rates. The widest boundaries were set by thermal growth conditions. Predicted flow rates for a 50-mm Rayleigh-step, helium-purge, annular seal underestimated measured flow rates by three to seven times. However, the analysis did accurately predict flow rates for choked gas flow through annular seals when compared to flow rates measured in two other independent studies.

  12. Greater focus needed on methane leakage from natural gas infrastructure.

    PubMed

    Alvarez, Ramón A; Pacala, Stephen W; Winebrake, James J; Chameides, William L; Hamburg, Steven P

    2012-04-24

    Natural gas is seen by many as the future of American energy: a fuel that can provide energy independence and reduce greenhouse gas emissions in the process. However, there has also been confusion about the climate implications of increased use of natural gas for electric power and transportation. We propose and illustrate the use of technology warming potentials as a robust and transparent way to compare the cumulative radiative forcing created by alternative technologies fueled by natural gas and oil or coal by using the best available estimates of greenhouse gas emissions from each fuel cycle (i.e., production, transportation and use). We find that a shift to compressed natural gas vehicles from gasoline or diesel vehicles leads to greater radiative forcing of the climate for 80 or 280 yr, respectively, before beginning to produce benefits. Compressed natural gas vehicles could produce climate benefits on all time frames if the well-to-wheels CH(4) leakage were capped at a level 45-70% below current estimates. By contrast, using natural gas instead of coal for electric power plants can reduce radiative forcing immediately, and reducing CH(4) losses from the production and transportation of natural gas would produce even greater benefits. There is a need for the natural gas industry and science community to help obtain better emissions data and for increased efforts to reduce methane leakage in order to minimize the climate footprint of natural gas.

  13. Albumin microvascular leakage in brains with diabetes mellitus.

    PubMed

    Fujihara, Ryuji; Chiba, Yoichi; Nakagawa, Toshitaka; Nishi, Nozomu; Murakami, Ryuta; Matsumoto, Koichi; Kawauchi, Machi; Yamamoto, Tetsuji; Ueno, Masaki

    2016-09-01

    Their aim was to examine whether microvascular leakage of endogenous albumin, a representative marker for blood-brain barrier (BBB) damage, was induced in the periventricular area of diabetic db/db mice because periventricular white matter hyperintensity formation in magnetic resonance images was accelerating in elderly patients with diabetes mellitus. Using light and electron microscopes, and semi-quantitative analysis techniques, immunoreactivity of endogenous albumin, indicating vascular permeability, was examined in the periventricular area and spinal cord of db/db mice and db/+m control mice. Greater immunoreactivity of albumin was observed in the vessel wall of the periventricular area of db/db mice than in controls. Additionally, weak immunoreactivity was observed in the spinal cord of both db/db mice and controls. The number of gold particles, indicating immunoreactivity of albumin, in the perivascular area of db/db mice was significantly higher than that of control mice, but there was no significant difference in the number of particles in the spinal cord between db/db mice and controls. These findings suggest that albumin microvascular leakage, or BBB breakdown, is induced in the periventricular area of diabetic mice. Microsc. Res. Tech. 79:833-837, 2016. © 2016 Wiley Periodicals, Inc. PMID:27333535

  14. Temperature spans for growth: Hypothesis and discussion

    SciTech Connect

    Wiegel, J. )

    1990-01-01

    In recent years the upper and lower temperature limits for growth of pure cultures of microorganisms have been extended at least to 110C and [minus]14C, respectively. There are no organisms which grow at both 0C and 100C and, therefore, organisms are grouped according to their ranges of growth temperatures. Thus, the questions of importance are: (1) What is the widest temperature range (temperature span) over which a single organism can grow and (2) How much can one alter the temperature spans of an organism The concept of cryptic thermophiles' is used to explain some of the published data on the latter question. A wider temperature range can be very important for organisms in various ways, since it makes an organism more versatile with regard to changes in the environment. Also, it enables the organism to utilize a wider range of ecological niches. Some aerobic and anaerobic extreme thermophiles will grow within a span of more than 40C. Furthermore, such organisms are regarded suitable for biotechnological applications as well. The following hypothesis is presented and discussed: these organisms have two sets of key enzymes, and their synthesis is regulated by temperature. Such organisms are capable of growing in two different ranges, such as the mesophilic and thermophilic ranges. The hypothesis is based on the fact that these bacteria exhibit broken Arrhenius plots, and is illustrated with 'temperature tolerant extreme thermophiles' as the major example. However, the hypothesis is not restricted to this group, but it also applicable to the 'temperature tolerant thermophiles and mesophiles'.

  15. Telomeres and longevity: testing an evolutionary hypothesis.

    PubMed

    Haussmann, Mark F; Mauck, Robert A

    2008-01-01

    Identifying mechanisms that underlie variation in adult survivorship provide insight into the evolution of life history strategies and phenotypic variation in longevity. There is accumulating evidence that shortening telomeres, the protective caps at the ends of chromosomes, play an important role in individual variation in longevity. Given that telomeres generally shorten with age, it was surprising to find that in a population of a long-lived seabird, Leach's storm petrel, telomeres appear to lengthen with age. This unique finding suggested that the longest lived individuals are able to elongate telomeres, an interpretation we call the "elongation hypothesis." Alternatively, the "selection hypothesis" states that the longest lived individuals start with the longest telomeres and variation in telomere length decreases with age due to the selective disappearance of individuals with short telomeres. In the same population in which evidence supporting both hypotheses was uncovered, we tested mutually exclusive predictions from the elongation and selection hypotheses by measuring telomere length with the telomere restriction fragment assay in hatchling and old, adult storm petrels. As previously found, adult birds had longer telomeres on average compared with hatchlings. We also found that 3 hatchlings had mean telomere lengths exceeding that of the most extreme old bird, old birds on average had longer initial telomere lengths than hatchlings, and the variance in mean telomere length was significantly greater for hatchlings than for old birds, all predicted by the selection hypothesis. Perhaps more surprisingly, the oldest adults also show little or no accumulation of short telomeres over time, a pattern unknown in other species. Long telomeres are thought to provide a buffer against cellular senescence and be generally indicative of genome stability and overall cell health. In storm petrels, because the progressive accumulation of short telomeres appears negligible

  16. Consumer Health Information Seeking as Hypothesis Testing

    PubMed Central

    Keselman, Alla; Browne, Allen C.; Kaufman, David R.

    2008-01-01

    Objective Despite the proliferation of consumer health sites, lay individuals often experience difficulty finding health information online. The present study attempts to understand users' information seeking difficulties by drawing on a hypothesis testing explanatory framework. It also addresses the role of user competencies and their interaction with internet resources. Design Twenty participants were interviewed about their understanding of a hypothetical scenario about a family member suffering from stable angina and then searched MedlinePlus® consumer health information portal for information on the problem presented in the scenario. Participants' understanding of heart disease was analyzed via semantic analysis. Thematic coding was used to describe information seeking trajectories in terms of three key strategies: verification of the primary hypothesis, narrowing search within the general hypothesis area and bottom-up search. Results Compared to an expert model, participants' understanding of heart disease involved different key concepts, which were also differently grouped and defined. This understanding provided the framework for search-guiding hypotheses and results interpretation. Incorrect or imprecise domain knowledge led individuals to search for information on irrelevant sites, often seeking out data to confirm their incorrect initial hypotheses. Online search skills enhanced search efficiency, but did not eliminate these difficulties. Conclusions Regardless of their web experience and general search skills, lay individuals may experience difficulty with health information searches. These difficulties may be related to formulating and evaluating hypotheses that are rooted in their domain knowledge. Informatics can provide support at the levels of health information portals, individual websites, and consumer education tools. PMID:18436912

  17. Updating the Lamellar Hypothesis of Hippocampal Organization

    PubMed Central

    Sloviter, Robert S.; Lømo, Terje

    2012-01-01

    Andersen et al. (1971) proposed that excitatory activity in the entorhinal cortex propagates topographically to the dentate gyrus, and on through a “trisynaptic circuit” lying within transverse hippocampal “slices” or “lamellae.” In this way, a relatively simple structure might mediate complex functions in a manner analogous to the way independent piano keys can produce a nearly infinite variety of unique outputs. The lamellar hypothesis derives primary support from the “lamellar” distribution of dentate granule cell axons (the mossy fibers), which innervate dentate hilar neurons and area CA3 pyramidal cells and interneurons within the confines of a thin transverse hippocampal segment. Following the initial formulation of the lamellar hypothesis, anatomical studies revealed that unlike granule cells, hilar mossy cells, CA3 pyramidal cells, and Layer II entorhinal cells all form axonal projections that are more divergent along the longitudinal axis than the clearly “lamellar” mossy fiber pathway. The existence of pathways with “translamellar” distribution patterns has been interpreted, incorrectly in our view, as justifying outright rejection of the lamellar hypothesis (Amaral and Witter, 1989). We suggest that the functional implications of longitudinally projecting axons depend not on whether they exist, but on what they do. The observation that focal granule cell layer discharges normally inhibit, rather than excite, distant granule cells suggests that longitudinal axons in the dentate gyrus may mediate “lateral” inhibition and define lamellar function, rather than undermine it. In this review, we attempt a reconsideration of the evidence that most directly impacts the physiological concept of hippocampal lamellar organization. PMID:23233836

  18. Migraine pathogenesis: the neural hypothesis reexamined.

    PubMed

    Blau, J N

    1984-05-01

    The hypothesis that migraine is a primary neurological disturbance with secondary vascular manifestations is tested by analysing the five phases of migraine attacks and the eight groups of recognised precipitating factors. Accessory evidence from cerebral blood flow and EEG recordings taken during attacks is also considered. The evidence supports the concept that the sensory cortex and hypothalamus could be initiating sites for migraine attacks, and indicates that a neurological mechanism, suggested by Liveing and Gowers 100 years ago, remains viable and needs to be considered in future research.

  19. The SSME seal test program: Leakage tests for helically-grooved seals

    NASA Technical Reports Server (NTRS)

    Childs, D. W.

    1983-01-01

    Helically grooved annular seal configurations were tested in highly turbulent flow to determine if reduced leakage and enhanced stability would result from the pumping action of the seal. It was found that: (1) leakage of a helically grooved seals decreases with running speed; (2) leakage reduction due to increased running speed is greater at lower values of R sub a; (3) an asymptote for leakage reduction is indicated with increasing running speed; (4) leakage is reduced by reducing the ridge (minimum) and average clearances; (5) leakage increases with increasing pitch angles and with increasing groove depth. Plain seals with smooth rotors and stators will leak more than a helically grooved seal. It was also found that plain seals with a rough rotor and a rough stator leak less than a properly designed helically grooved seal. A properly designed helically grooved seal consumes at least twice as much power as a conventional annular seal.

  20. Leakage detection and location in gas pipelines through an LPV identification approach

    NASA Astrophysics Data System (ADS)

    Lopes dos Santos, P.; Azevedo-Perdicoúlis, T.-P.; Jank, G.; Ramos, J. A.; Martins de Carvalho, J. L.

    2011-12-01

    A new approach to gas leakage detection in high pressure distribution networks is proposed, where two leakage detectors are modelled as a linear parameter varying (LPV) system whose scheduling signals are, respectively, intake and offtake pressures. Running the two detectors simultaneously allows for leakage location. First, the pipeline is identified from operational data, supplied by REN-Gasodutos and using an LPV systems identification algorithm proposed in [1]. Each leakage detector uses two Kalman filters where the fault is viewed as an augmented state. The first filter estimates the flow using a calculated scheduling signal, assuming that there is no leakage. Therefore it works as a reference. The second one uses a measured scheduling signal and the augmented state is compared with the reference value. Whenever there is a significant difference, a leakage is detected. The effectiveness of this method is illustrated with an example where a mixture of real and simulated data is used.