Gravitropism in caulonemata of the moss Pottia intermedia

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Chaban, C. I.; Kern, V. D.; Ripetskyj, R. T.; Demkiv, O. T.; Sack, F. D.

1998-01-01

The gravitropism of caulonemata of Pottia intermedia is described and compared with that of other mosses. Spore germination produces primary protonemata including caulonemata which give rise to buds that form the leafy moss plant, the gametophore. Primary caulonemata are negatively gravitropic but their growth and the number of filaments are limited in the dark. Axenic culture of gametophores results in the production of secondary caulonemata that usually arise near the leaf base. Secondary protonemata that form in the light are agravitropic. Secondary caulonemata that form when gametophores are placed in the dark for several days show strong negative gravitropism and grow well in the dark. When upright caulonemata are reorientated to the horizontal or are inverted, upward bending can be detected after 1 h and caulonemata reach the vertical within 1-2 d. Clear amyloplast sedimentation occurs 10-15 minutes after horizontal placement and before the start of upward curvature. This sedimentation takes place in a sub-apical zone. Amyloplast sedimentation also takes place along the length of upright and inverted Pottia protonemata. These results support the hypothesis that amyloplast sedimentation functions in gravitropic sensing since sedimentation occurs before gravitropism in Pottia and since the location and presence of a unique sedimentation zone is conserved in all four mosses known to gravitropic protonomata.

Amyloplast Distribution Directs a Root Gravitropic Reaction

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Kordyum, Elizabeth

with regard to the participation of calcium ions and cytoskeletal elements in these processes is therefore substantial but still circumstantial and requires new experimental data. Using a new model - weak combined magnetic fields (CMFs), which elicit a variety of responses in plants, growth rate and fresh weight, seed germination, Ca2+ concentration, membrane permeability, with a frequency resonance to cyclotron frequency of calcium ions, we firstly showed that a root positive gravitropic reaction changes on a negative one. In this case, the paradoxical displacement of amylopasts-statoliths to the upper longitudinal cell wall of statocytes occurred in the direction opposite to a gravitational vector. Displacement of amyloplasts, which contain the abundance of free Ca2+ in the stroma, was accompanied with Ca2+ redistribution in the same direction in the cytosol and increasing around amyloplasts in comparison with the state magnetic field. In the elongation zone, calcium ions accumulated in the upper site of a gravistimulated root unlike a positive gravitropic reaction, and a root is bending in the same direction in which amyloplasts are displacing. It seems that a root gravitropic reaction, if it began, occurs by an usual physiological way resulting in root bending with an opposite sign. It is of a special interest that a root is bending to the same direction with displacing of amyloplasts: in positive gravitropism - downwards, in negative gravitropism - upwards. Peculiarities of calcium ion redistribution in statocytes under gravistimulation in such combined magnetic field are a new additional evidence of a Ca2+ ion significant role in gravitropism. Thus, our data support the starch-statolith hypothesis but also pose the question as to which forces displace amyloplasts against the gravity vector? We hope that these data will stimulate new research to better understand the mechanisms of plant graviperception and graviresponse. Gravistimulation of a root in the CMF with

Callose deposition during gravitropism of Zea mays and Pisum sativum and its inhibition by 2-deoxy-D-glucose

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Jaffe, M. J.; Leopold, A. C.

1984-01-01

In etiolated corn (Zea mays L.) and etiolated pea (Pisum sativum L.) seedlings, a gravitropic stimulation induces the deposition of callose. In the corn coleoptiles this occurs within 5 min of gravity stimulation, and prior to the beginning of curvature. Both gravitropic curvature and callose deposition reach their maxima by 12 h. Within the first 2 h more callose is deposited on the upper (concave) side, but after 2-3 h, this deposition pattern is reversed. An inhibitor of protein glycosylation, 2-deoxy-D-glucose (DDG), inhibits callose production and considerably retards gravitropic bending in both species of plants. Mannose can relieve the inhibition of gravitropic bending by DDG. The pea mutant "Ageotropum", which does not respond to gravity when etiolated, also fails to produce callose in response to a gravitic stimulus. These correlations indicate that callose deposition may be a biochemical component of gravitropism in plant shoots.

Inhibition of polar calcium movement and gravitropism in roots treated with auxin-transport inhibitors

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Lee, J. S.; Mulkey, T. J.; Evans, M. L.

1984-01-01

Primary roots of maize (Zea mays L.) and pea (Pisum sativum L.) exhibit strong positive gravitropism. In both species, gravistimulation induces polar movement of calcium across the root tip from the upper side to the lower side. Roots of onion (Allium cepa L.) are not responsive to gravity and gravistimulation induces little or no polar movement of calcium across the root tip. Treatment of maize or pea roots with inhibitors of auxin transport (morphactin, naphthylphthalamic acid, 2,3,5-triiodobenzoic acid) prevents both gravitropism and gravity-induced polar movement of calcium across the root tip. The results indicate that calcium movement and auxin movement are closely linked in roots and that gravity-induced redistribution of calcium across the root cap may play an important role in the development of gravitropic curvature.

Inhibitory effects of KN-93, an inhibitor of Ca2+ calmodulin-dependent protein kinase II, on light-regulated root gravitropism in maize

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Feldman, L. J.; Hidaka, H.

1993-01-01

Light is essential for root gravitropism in Zea mays L., cultivar Merit. It is hypothesized that calcium mediates this light-regulated response. KN-93, an inhibitor of calcium/calmodulin kinase II (CaMK II), inhibits light-regulated root gravitropism but does not affect light perception. We hypothesize that CaMK II, or a homologue, operates late in the light/gravity signal transduction chain. Here we provide evidence suggesting a possible physiological involvement of CaMK II in root gravitropism in plants.

Genetics of the gravitropic set-point angle in lateral organs of Arabidopsis

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Mullen, J.; Hangarter, R.

Research on gravity responses in plants has mostly focused on primary roots and shoots, which typically orient to a vertical orientation. However, the distribution of lateral organs and their typically non-vertical growth orientation are critical for the determination of plant form. For example, in Arabidopsis, when lateral roots emerge from the primary root, they grow at a nearly horizontal orientation. As they elongate, the roots slowly curve until they eventually reach a vertical orientation. The regulation of this lateral root orientation is an important component affecting the overall root system architecture. We found that this change in orientation is not simply due to the onset of gravitropic competence, as non-vertical lateral roots are capable of both positive and negative gravitropism. Thus, the horizontal growth the new lateral roots is determined by what is called the gravitropic set-point angle (GSA). This developmental control of the GSA of lateral roots in Arabidopsis provides a useful system for investigating the components involved in regulating gravitropic responses. Using this system, we have identified several Arabidopsis mutants that have altered lateral root orientations but maintain normal primary root orientation. Two of these mutants also have altered orientation of their rosette leaves, indicating some common mechanisms in the positioning of root and shoot lateral organs. Rosette leaves and lateral roots also have in common a regulation of orientation by red light that may be due to red-light-dependent changes in the GSA. Further molecular and physiological analyses of the GSA mutants will provide insight into the basis of GSA regulation and, thus, a better understanding of how gravity controls plant architecture. [This work was supported by the National Aeronautics and Space Administration through grant no. NCC 2-1200.

Transcriptional and Hormonal Regulation of Gravitropism of Woody Stems in Populus

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Suzanne Gerttula; Matthew S. Zinkgraf; Gloria K. Muday; Daniel R. Lewis; Farid M. Ibatullin; Harry Brumer; Foster Hart; Shawn D. Mansfield; Vladimir Filkov; Andrew Groover

2015-01-01

Angiosperm trees reorient their woody stems by asymmetrically producing a specialized xylem tissue, tension wood, which exerts a strong contractile force resulting in negative gravitropism of the stem. Here, we show, in Populus trees, that initial gravity perception and response occurs in specialized cells through sedimentation of starch-filled...

Actin is an essential component of plant gravitropic signaling pathways

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Braun, Markus; Hauslage, Jens; Limbach, Christoph

2003-08-01

A role of the actin cytoskeleton in the different phases of gravitropism in higher plant organs seems obvious, but experimental evidence is still inconclusive and contradictory. In gravitropically tip-growing rhizoids and protonemata, however, it is well documented that actin is an essential component of the tip-growth machinery and is involved either in the cellular mechanisms that lead to gravity sensing and in the processes of the graviresponses that result in the reorientation of the growth direction. All these processes depend on a complexly organized and highly dynamic organization of actin filaments whose diverse functions are coordinated by numerous associated proteins. Actin filaments and myosins mediate the transport of secretory vehicles to the growing tip and precisely control the delivery of cell wall material. In addition, both cell types use a very efficient actomyosin-based system to control and correct the position of their statoliths and to direct sedimenting statoliths to confined graviperception sites at the plasma membrane. The studies presented in this paper provide evidence for the essential role of actin in plant gravity sensing and the gravitropic responses. A unique actin-organizing center exists in the tip of characean rhizoids and protonemata which is associated with and dynamically regulated by a specific set of actin-dynamizing proteins. It is concluded that this highly dynamic apical actin array is an essential prerequisite for gravity sensing and gravity-oriented tip growth.

Gravitropism in higher plant shoots. VI. Changing sensitivity to auxin in gravistimulated soybean hypocotyls

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Rorabaugh, P. A.; Salisbury, F. B.

1989-01-01

Although the Cholodny-Went model of auxin redistribution has been used to explain the transduction phase of gravitropism for over 60 years, problems are apparent, especially with dicot stems. An alternative to an auxin gradient is a physiological gradient in which lower tissues of a horizontal stem become more sensitive than upper tissues to auxin already present. Changes in tissue sensitivity to auxin were tested by immersing marked Glycine max Merrill (soybean) hypocotyl sections in buffered auxin solutions (0, 10(-8) to 10(-2) molar indoleacetic acid) and observing bending and growth of upper and lower surfaces. The two surfaces of horizontal hypocotyl sections responded differently to the same applied auxin stimulus; hypocotyls bent up (lower half grew more) in buffer alone or in low auxin levels, but bent down (upper half grew more) in high auxin. Dose-response curves were evaluated with Michaelis-Menten kinetics, with auxin-receptor binding analogous to enzyme-substrate binding. Vmax for the lower half was usually greater than that for the upper half, which could indicate more binding sites in the lower half. Km of the upper half was always greater than that of the lower half (unmeasurably low), which could indicate that upper-half binding sites had a much lower affinity for auxin than lower-half sites. Dose-response curves were also obtained for sections scrubbed' (cuticle abraded) on top or bottom before immersion in auxin, and gravitropic memory' experiments of L. Brauner and A. Hagar (1958 Planta 51: 115-147) were duplicated. [1-14C]Indoleacetic acid penetration was equal into the two halves, and endogenous plus exogenously supplied (not radiolabeled) free auxin in the two halves (by gas chromatography-selected ion monitoring-mass spectrometry) was also equal. Thus, differential growth occurred without free auxin redistribution, contrary to Cholodny-Went but in agreement with a sensitivity model.

The effect of the external medium on the gravitropic curvature of rice (Oryza sativa, Poaceae) roots

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Staves, M. P.; Wayne, R.; Leopold, A. C.

1997-01-01

The roots of rice seedlings, growing in artificial pond water, exhibit robust gravitropic curvature when placed perpendicular to the vector of gravity. To determine whether the statolith theory (in which intracellular sedimenting particles are responsible for gravity sensing) or the gravitational pressure theory (in which the entire protoplast acts as the gravity sensor) best accounts for gravity sensing in rice roots, we changed the physical properties of the external medium with impermeant solutes and examined the effect on gravitropism. As the density of the external medium is increased, the rate of gravitropic curvature decreases. The decrease in the rate of gravicurvature cannot be attributed to an inhibition of growth, since rice roots grown in 100 Osm/m3 (0.248 MPa) solutions of different densities all support the same root growth rate but inhibit gravicurvature increasingly with increasing density. By contrast, the sedimentation rate of amyloplasts in the columella cells is unaffected by the external density. These results are consistent with the gravitational pressure theory of gravity sensing, but cannot be explained by the statolith theory.

Disruption of the actin cytoskeleton results in the promotion of gravitropism in inflorescence stems and hypocotyls of Arabidopsis

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Yamamoto, Kazuyoshi; Kiss, John Z.

2002-01-01

The actin cytoskeleton is hypothesized to play a major role in gravity perception and transduction mechanisms in roots of plants. To determine whether actin microfilaments (MFs) are involved in these processes in stem-like organs, we studied gravitropism in Arabidopsis inflorescence stems and hypocotyls. Localization studies using Alexa Fluor-phalloidin in conjugation with confocal microscopy demonstrated a longitudinally and transversely oriented actin MF network in endodermal cells of stems and hypocotyls. Latrunculin B (Lat-B) treatment of hypocotyls caused depolymerization of actin MFs in endodermal cells and a significant reduction of hypocotyl growth rates. Actin MFs in Lat-B-treated inflorescence stems also were disrupted, but growth rates were not affected. Despite disruption of the actin cytoskeleton in these two organs, Lat-B-treated stems and hypocotyls exhibited a promotion of gravitropic curvature in response to reorientation. In contrast, Lat-B reduced gravitropic curvature in roots but also reduced the growth rate. Thus, in contrast to prevailing hypotheses, our results suggest that actin MFs are not a necessary component of gravitropism in inflorescence stems and hypocotyls. Furthermore, this is the first study to demonstrate a prominent actin MF network in endodermal cells in the putative gravity-perceiving cells in stems.

The Ca2+ pump inhibitor, thapsigargin, inhibits root gravitropism in Arabidopsis thaliana

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DANIELA C URBINA

2006-01-01

Full Text Available Thapsigargin, a specific inhibitor of most animal intracellular SERCA-type Ca2+ pumps present in the sarcoplasmic/endoplasmic reticulum, was originally isolated from the roots of the Mediterranean plant Thapsia gargancia L. Here, we demonstrate that this root-derived compound is capable of altering root gravitropism in Arabidopsis thaliana. Thapsigargin concentrations as low as 0.1 µM alter root gravitropism whereas under similar conditions cyclopiazonic acid does not. Furthermore, a fluorescently conjugated thapsigargin (BODIPY FL thapsigargin suggests that target sites for thapsigargin are located in intracellular organelles in the root distal elongation zone and the root cap, regions known to regulate root gravitropism

Gravitropic reaction of primary seminal roots of Zea mays L. influenced by temperature and soil water potential.

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Nakamoto, T

1995-03-01

The growth of the primary seminal root of maize (Zea mays L.) is characterized by an initial negative gravitropic reaction and a later positive one that attains a plagiotropic liminal angle. The effects of temperature and water potential of the surrounding soil on these gravitropic reactions were studied. Temperatures of 32, 25, and 18C and soil water potentials of -5, -38, and -67 kPa were imposed and the direction of growth was measured for every 1 cm length of the root. The initial negative gravitropic reaction extended to a distance of about 10 cm from the grain. Higher temperatures reduced the initial negative gravitropic reaction. Lower soil water potential induced a downward growth at root emergence. A mathematical model, in which it was assumed that the rate of the directional change of root growth was a sum of a time-dependent negative gravitropic reaction and an establishment of the liminal angle, adequately fitted the distance-angle relations. It was suggested that higher temperatures and/or a lower water potential accelerated the diminution of the initial negative gravitropic reaction.

Effects of abscisic acid and xanthoxin on elongation and gravitropism in primary roots of Zea mays

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Lee, J. S.; Hasenstein, K. H.; Mulkey, T. J.; Yang, R. L.; Evans, M. L.

1990-01-01

We examined the involvement of abscisic acid (ABA) and xanthoxin (Xan) in maize root gravitropism by (1) testing the ability of ABA to allow positive gravitropism in dark-grown seedlings of the maize cultivar LG11, a cultivar known to require light for positive gravitropism of the primary root, (2) comparing curvature in roots in which half of the cap had been excised and replaced with agar containing either ABA or indole-3-acetic acid (IAA), (3) measuring gravitropism in roots of seedlings submerged in oxygenated solutions of ABA or IAA and (4) testing the effect of Xan on root elongation. Using a variety of methods of applying ABA to the root, we found that ABA did not cause horizontally-oriented primary roots of dark-grown seedlings to become positively gravitropic. Replacing half of the root cap of vertically oriented roots with an agar block containing ABA had little or no effect on curvature relative to that of controls in which the half cap was replaced by a plain agar block. Replacement of the removed half cap with IAA either canceled or reversed the curvature displayed by controls. When light-grown seedlings were submerged in ABA they responded strongly to gravistimulation while those in IAA did not. Xan (up to 0.1 mM) did not affect root elongation. The results indicate that ABA is not a likely mediator of root gravitropism and that the putative ABA precursor, Xan, lacks the appropriate growth-inhibiting properties to serve as a mediator of root gravitropism.

Space-time analysis of gravitropism in etiolated Arabidopsis hypocotyls using bioluminescence imaging of the IAA19 promoter fusion with a destabilized luciferase reporter.

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Yamamoto, Kotaro T; Watahiki, Masaaki K; Matsuzaki, Jun; Satoh, Soichirou; Shimizu, Hisayo

2017-07-01

Imaging analysis was carried out during the gravitropic response of etiolated Arabidopsis hypocotyls, using an IAA19 promoter fusion of destabilized luciferase as a probe. From the bright-field images we obtained the local deflection angle to the vertical, A, local curvature, C, and the partial derivative of C with respect to time, [Formula: see text]. These were determined every 19.9 µm along the curvilinear length of the hypocotyl, at ~10 min intervals over a period of ~6 h after turning hypocotyls through 90° to the horizontal. Similarly from the luminescence images we measured the luminescence intensity of the convex and concave flanks of the hypocotyl as well as along the median of the hypocotyl, to determine differential expression of auxin-inducible IAA19. Comparison of these parameters as a function of time and curvilinear length shows that the gravitropic response is composed of three successive elements: the first and second curving responses and a decurving response (autostraightening). The maximum of the first curving response occurs when A is 76° along the entire length of the hypocotyl, suggesting that A is the sole determinant in this response; in contrast, the decurving response is a function of both A and C, as predicted by the newly-proposed graviproprioception model (Bastien et al., Proc Natl Acad Sci USA 110:755-760, 2013). Further, differential expression of IAA19, with higher expression in the convex flank, is observed at A = 44°, and follows the Sachs' sine law. This also suggests that IAA19 is not involved in the first curving response. In summary, the gravitropic response of Arabidopsis hypocotyls consists of multiple elements that are each determined by separate principles.

Changes in cytosolic pH within Arabidopsis root columella cells play a key role in the early signaling pathway for root gravitropism

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Scott, A. C.; Allen, N. S.; Davies, E. (Principal Investigator)

1999-01-01

Ratiometric wide-field fluorescence microscopy with 1',7'- bis-(2-carboxyethyl)-5-(and-6)-carboxyfluorescein (BCECF)-dextran demonstrated that gravistimulation leads to rapid changes in cytoplasmic pH (pHc) in columella cells of Arabidopsis roots. The pHc of unstimulated columella cells in tiers 2 and 3, known sites of graviperception (E.B. Blancaflor, J.B. Fasano, S. Gilroy [1998] Plant Physiol 116: 213-222), was 7.22 +/- 0.02 pH units. Following gravistimulation, the magnitude and direction of pHc changes in these cells depended on their location in the columella. Cells in the lower side of tier 2 became more alkaline by 0.4 unit within 55 s of gravistimulation, whereas alkalinization of the cells on the upper side was slower (100 s). In contrast, all cells in tier 3 acidified by 0.4 pH unit within 480 s after gravistimulation. Disrupting these pHc changes in the columella cells using pHc modifiers at concentrations that do not affect root growth altered the gravitropic response. Acidifying agents, including bafilomycin A1, enhanced curvature, whereas alkalinizing agents disrupted gravitropic bending. These results imply that pHc changes in the gravisensing cells and the resultant pH gradients across the root cap are important at an early stage in the signal cascade leading to the gravitropic response.

Inhibition of phospholipase C disrupts cytoskeletal organization and gravitropic growth in Arabidopsis roots.

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Andreeva, Zornitza; Barton, Deborah; Armour, William J; Li, Min Y; Liao, Li-Fen; McKellar, Heather L; Pethybridge, Kylie A; Marc, Jan

2010-10-01

The phospholipase protein superfamily plays an important role in hormonal signalling and cellular responses to environmental stimuli. There is also growing evidence for interactions between phospholipases and the cytoskeleton. In this report we used a pharmacological approach to investigate whether inhibiting a member of the phospholipase superfamily, phospholipase C (PLC), affects microtubules and actin microfilaments as well as root growth and morphology of Arabidopsis thaliana seedlings. Inhibiting PLC activity using the aminosteroid U73122 significantly inhibited root elongation and disrupted root morphology in a concentration-dependent manner, with the response being saturated at 5 μM, whereas the inactive analogue U73343 was ineffective. The primary root appeared to lose growth directionality accompanied by root waving and formation of curls. Immunolabelling of roots exposed to increasingly higher U73122 concentrations revealed that the normal transverse arrays of cortical microtubules in the elongation zone became progressively more disorganized or depolymerized, with the disorganization appearing within 1 h of incubation. Likewise, actin microfilament arrays also were disrupted. Inhibiting PLC using an alternative inhibitor, neomycin, caused similar disruptions to both cytoskeletal organization and root morphology. In seedlings gravistimulated by rotating the culture plates by 90°, both U73122 and neomycin disrupted the normal gravitropic growth of roots and etiolated hypocotyls. The effects of PLC inhibitors are therefore consistent with the notion that, as with phospholipases A and D, PLC likewise interacts with the cytoskeleton, alters growth morphology, and is involved in gravitropism.

Characterizing pathways by which gravitropic effectors could move from the root cap to the root of primary roots of Zea mays

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Moore, R.; McClelen, C. E.

1989-01-01

Plasmodesmata linking the root cap and root in primary roots Zea mays are restricted to approx. 400 protodermal cells bordering approx. 110000 microns2 of the calyptrogen of the root cap. This area is less than 10% of the cross-sectional area of the root-tip at the cap junction. Therefore, gravitropic effectors moving from the root cap to the root can move symplastically only through a relatively small area in the centre of the root. Decapped roots are non-responsive to gravity. However, decapped roots whose caps are replaced immediately after decapping are strongly graviresponsive. Thus, gravicurvature occurs only when the root cap contacts the root, and symplastic continuity between the cap and root is not required for gravicurvature. Completely removing mucilage from the root tip renders the root non-responsive to gravity. Taken together, these data suggest that gravitropic effectors move apoplastically through mucilage from the cap to the root.

Characterization of a calcium/calmodulin-dependent protein kinase homolog from maize roots showing light-regulated gravitropism

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Lu, Y. T.; Hidaka, H.; Feldman, L. J.

1996-01-01

Roots of many species respond to gravity (gravitropism) and grow downward only if illuminated. This light-regulated root gravitropism is phytochrome-dependent, mediated by calcium, and inhibited by KN-93, a specific inhibitor of calcium/calmodulin-dependent protein kinase II (CaMK II). A cDNA encoding MCK1, a maize homolog of mammalian CaMK, has been isolated from roots of maize (Zea mays L.). The MCK1 gene is expressed in root tips, the site of perception for both light and gravity. Using the [35S]CaM gel-overlay assay we showed that calmodulin-binding activity of the MCK1 is abolished by 50 microM KN-93, but binding is not affected by 5 microM KN-93, paralleling physiological findings that light-regulated root gravitropism is inhibited by 50 microM KN-93, but not by 5 microM KN-93. KN-93 inhibits light-regulated gravitropism by interrupting transduction of the light signal, not light perception, suggesting that MCK1 may play a role in transducing light. This is the first report suggesting a physiological function for a CaMK homolog in light signal transduction.

Infrared light-emitting diode radiation causes gravitropic and morphological effects in dark-grown oat seedlings

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Johnson, C. F.; Brown, C. S.; Wheeler, R. M.; Sager, J. C.; Chapman, D. K.; Deitzer, G. F.

1996-01-01

Oat (Avena sativa cv Seger) seedlings were irradiated with IR light-emitting diode (LED) radiation passed through a visible-light-blocking filter. Infrared LED irradiated seedlings exhibited differences in growth and gravitropic response when compared to seedlings grown in darkness at the same temperature. Thus, the oat seedlings in this study were able to detect IR LED radiation. These findings call into question the use of IR LED as a safe-light for some photosensitive plant response experiments. These findings also expand the defined range of wavelengths involved in radiation-gravity (light-gravity) interactions to include wavelengths in the IR region of the spectrum.

Gibberellins and gravitropism in maize shoots: endogenous gibberellin-like substances and movement and metabolism of [3H]Gibberellin A20

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Rood, S. B.; Kaufman, P. B.; Abe, H.; Pharis, R. P.

1987-01-01

from these lower leaf sheath pulvini by capillary gas chromatography-selected ion monitoring. Results from all of these experiments are consistent with a role for GAs in the differential shoot growth that follows gravitropism, although the results do not eliminate the possibility that the redistribution of GAs results from the gravitropic response.

Control of gravitropic orientation. I. Non-vertical orientation by primary roots of maize results from decay of competence for orthogravitropic induction

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LaMotte, Clifford E.; Pickard, Barbara G.

2004-01-01

Plant organs may respond to gravity by vertical (orthogravitropic), oblique (plagiogravitropic) or horizontal (diagravitropic) growth. Primary roots of maize (Zea mays L.) provide a good system for studying such behaviours because they are reportedly capable of displaying all three responses. In current work using maize seedlings of the Silver Queen cultivar, stabilisation of growth at an oblique orientation was commonplace. Hypothetically, plagiogravitropism may be accomplished either by a process we call graded orthogravitropism or by hunting about a sensed non-vertical setpoint. In graded orthotropism primary bending is unidirectional and depends on facilitative stimuli that determine its extent. The hallmark of the setpoint mechanism is restorative curvature of either sign following a displacement; both diagravitropism and orthogravitropism are based on setpoints. Roots settled in a plagiogravitropic orientation were tested with various illumination and displacement protocols designed to distinguish between these two hypotheses. The tests refuted the setpoint hypothesis and supported that of graded orthotropism. No evidence of diagravitropism could be found, thus, earlier claims were likely based on inadequately controlled observations of graded orthotropism. We propose that orthotropism is graded by the sequential action of dual gravity receptors: induction of a vectorial gravitropic response requires gravitational induction of a separate facilitative response, whose decay in the absence of fresh stimuli can brake gravitropism at plagiotropic angles.

Comparative effects of auxin and abscisic acid on growth, hydrogen ion efflux and gravitropism in primary roots of maize

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Evans, M. L.; Mulkey, T. J.

1984-01-01

In order to test the idea that auxin action on root growth may be mediated by H(+) movement, the correlation of auxin action on growth and H(+) movement in roots was examined along with changes in H(+) efflux patterns associated with the asymmetric growth which occurs during gravitropism. The effects of indoleacetic acid (IAA) and abscisic acid (AbA) on growth, H(+) secretion, and gravitropism in roots were compared. Results show a close correlation existent between H(+) efflux and growth in maize roots. In intact roots there is strong H(+) efflux from the elongation zone. Growth-promoting concentrations of IAA stimulate H(+) efflux. During gravitropism the H(+) efflux from the elongation zone becomes asymmetric; the evidence indicates that auxin redistribution contributes to the development of acid efflux asymmetry. That AbA stimulates root growth is reflected in its ability to stimulate H(+) efflux from apical root segments.

Identification of a Gravitropism-Deficient Mutant in Rice

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He Yan

2017-03-01

Full Text Available A gravitropism-deficient mutant M96 was isolated from a mutant bank, generated by ethyl methane sulfonate (EMS mutagenesis of indica rice accession ZJ100. The mutant was characterized as prostrate growth at the beginning of germination, and the prostrate growth phenotype ran through the whole life duration. Tiller angle and tiller number of M96 increased significantly in comparison with the wild type. Tissue section observation analysis indicated that asymmetric stem growth around the second node occurred in M96. Genetic analysis and gene mapping showed that M96 was controlled by a single recessive nuclear gene, tentatively termed as gravitropism-deficient M96 (gdM96, which was mapped to a region of 506 kb flanked by markers RM5960 and InDel8 on the long arm of chromosome 11. Sequencing analysis of the open reading frames in this region revealed a nucleotide substitution from G to T in the third exon of LOC_Os11g29840. Additionally, real-time fluorescence quantitative PCR analysis showed that the expression level of LOC_Os11g29840 in the stems was much higher than in the roots and leaves in M96. Furthermore, the expression level was more than four times in M96 stem than in the wild type stem. Our results suggested that the mutant gene was likely a new allele to the reported gene LAZY1. Isolation of this new allele would facilitate the further characterization of LAZY1.

Analysis of growth patterns during gravitropic curvature in roots of Zea mays by use of a computer-based video digitizer

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Nelson, A. J.; Evans, M. L.

1986-01-01

A computer-based video digitizer system is described which allows automated tracking of markers placed on a plant surface. The system uses customized software to calculate relative growth rates at selected positions along the plant surface and to determine rates of gravitropic curvature based on the changing pattern of distribution of the surface markers. The system was used to study the time course of gravitropic curvature and changes in relative growth rate along the upper and lower surface of horizontally-oriented roots of maize (Zea mays L.). The growing region of the root was found to extend from about 1 mm behind the tip to approximately 6 mm behind the tip. In vertically-oriented roots the relative growth rate was maximal at about 2.5 mm behind the tip and declined smoothly on either side of the maximum. Curvature was initiated approximately 30 min after horizontal orientation with maximal (50 degrees) curvature being attained in 3 h. Analysis of surface extension patterns during the response indicated that curvature results from a reduction in growth rate along both the upper and lower surfaces with stronger reduction along the lower surface.

High-resolution mapping and genetic characterization of the Lazy-2 gravitropic mutant of tomato

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Behringer, F. J.; Lomax, T. L.

1999-01-01

Mutation of the Lazy-2 (Lz-2) gene in tomato (Lycopersicon esculentum mill.) produces a phytochrome-dependent reversal of shoot gravitropism, providing a unique genetic resource for investigating how signals from light modulate gravitropism. We mapped the Lz-2 gene using RFLPs and a PCR-based technique to assess the feasibility of positional cloning. Analysis of a 1338 plant backcross population between L. esculentum and L. pennellii placed Lz-2 within a 1.2 cM interval on chromosome 5, 0.4 cM from TG504-CT201A interval. The inabililty to resolve these markers indicates that Lz-2 resides in a centromeric region in which recombination is highly suppressed. Lazy-2 is tightly linked to but does not encode the gene for ACC4, an enzyme involved in ethylene biosynthesis. We also observed that Lz-2 is partially dominant under certain conditions and stages of development.

An Arabidopsis E3 Ligase, SHOOT GRAVITROPISM9, Modulates the Interaction between Statoliths and F-Actin in Gravity Sensing[W][OA

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Nakamura, Moritaka; Toyota, Masatsugu; Tasaka, Masao; Morita, Miyo Terao

2011-01-01

Higher plants use the sedimentation of amyloplasts in statocytes as statolith to sense the direction of gravity during gravitropism. In Arabidopsis thaliana inflorescence stem statocyte, amyloplasts are in complex movement; some show jumping-like saltatory movement and some tend to sediment toward the gravity direction. Here, we report that a RING-type E3 ligase SHOOT GRAVITROPISM9 (SGR9) localized to amyloplasts modulates amyloplast dynamics. In the sgr9 mutant, which exhibits reduced gravitropism, amyloplasts did not sediment but exhibited increased saltatory movement. Amyloplasts sometimes formed a cluster that is abnormally entangled with actin filaments (AFs) in sgr9. By contrast, in the fiz1 mutant, an ACT8 semidominant mutant that induces fragmentation of AFs, amyloplasts, lost saltatory movement and sedimented with nearly statically. Both treatment with Latrunculin B, an inhibitor of AF polymerization, and the fiz1 mutation rescued the gravitropic defect of sgr9. In addition, fiz1 decreased saltatory movement and induced amyloplast sedimentation even in sgr9. Our results suggest that amyloplasts are in equilibrium between sedimentation and saltatory movement in wild-type endodermal cells. Furthermore, this equilibrium is the result of the interaction between amyloplasts and AFs modulated by the SGR9. SGR9 may promote detachment of amyloplasts from AFs, allowing the amyloplasts to sediment in the AFs-dependent equilibrium of amyloplast dynamics. PMID:21602290

Circumnutation and its dependence on the gravity response in rice, morning glory and pea plants: verification by spaceflight experiments

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Takahashi, Hideyuki; Kobayashi, Akie; Fujii, Nobuharu; Yano, Sachiko; Shimazu, Toru; Kim, Hyejeong; Tomita, Yuuta; Miyazawa, Yutaka

Plant organs display helical growth movement known as circumnutation. This movement helps plant organs find suitable environmental cues. The amplitude, period and shape of the circumnutation differ depending on plant species or organs. Although the mechanism for circumnutation is unclear, it has long been argued whether circumnutation is involved with gravitropic response. Previously, we showed that shoots of weeping morning glory (we1 and we2) are impaired in not only the differentiation of endodermis (gravisensing cells) and gravitropic response, but also winding and circumnutation (Kitazawa et al., PNAS 102: 18742-18747, 2005). Here, we report a reduced circumnutation in the shoots of rice and the roots of pea mutants defective in gravitropic response. Coleoptiles of clinorotated rice seedlings and decapped roots of pea seedlings also showed a reduction of their circumnutational movement. These results suggest that circumnutation is tightly related with gravitropic response. In the proposed spaceflight experiments, “Plant Rotation”, we will verify the hypothesis that circumnutation requires gravity response, by using microgravity environment in KIBO module of the International Space Station. We will grow rice and morning glory plants under both muG and 1G conditions on orbit and monitor their growth by a camera. The downlinked images will be analyzed for the measurements of plant growth and nutational movements. This experiment will enable us to answer the question whether circumnutation depends on gravity response or not.

Calcium movements and the cellular basis of gravitropism

Science.gov (United States)

Roux, S. J.; Biro, R. L.; Hale, C. C.

An early gravity-transduction event in oat coleoptiles which precedes any noticeable bending is the accumulation of calcium on their prospective slower-growing side. Sub-cellular calcium localization studies indicate that the gravity-stimulated redistribution of calcium results in an increased concentration of calcium in the walls of responding cells. Since calcium can inhibit the extension growth of plant cell walls, this selective accumulation of calcium in walls may play a role in inducing the asymmetry of growth which characterizes gravitropism. The active transport of calcium from cells into walls is performed by a calcium-dependent ATPase localized in the plasma membrane. Evidence is presented in support of the hypothesis that this calcium pump is regulated by a feed-back mechanism which includes the participation of calmodulin.

Analysis of magnetic gradients to study gravitropism.

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Hasenstein, Karl H; John, Susan; Scherp, Peter; Povinelli, Daniel; Mopper, Susan

2013-01-01

Gravitropism typically is generated by dense particles that respond to gravity. Experimental stimulation by high-gradient magnetic fields provides a new approach to selectively manipulate the gravisensing system. The movement of corn, wheat, and potato starch grains in suspension was examined with videomicroscopy during parabolic flights that generated 20 to 25 s of weightlessness. During weightlessness, a magnetic gradient was generated by inserting a wedge into a uniform, external magnetic field that caused repulsion of starch grains. The resultant velocity of movement was compared with the velocity of sedimentation under 1 g conditions. The high-gradient magnetic fields repelled the starch grains and generated a force of at least 0.6 g. Different wedge shapes significantly affected starch velocity and directionality of movement. Magnetic gradients are able to move diamagnetic compounds under weightless or microgravity conditions and serve as directional stimulus during seed germination in low-gravity environments. Further work can determine whether gravity sensing is based on force or contact between amyloplasts and statocyte membrane system.

Diagnostic of Gravitropism-like Stabilizer of Inspection Drone Using Neural Networks

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Kruglova, Tatyana; Sayfeddine, Daher; Bulgakov, Alexey

2018-03-01

This paper discusses the enhancement of flight stability of using an inspection drone to scan the condition of buildings on low and high altitude. Due to aerial perturbations and wakes, the drone starts to shake and may be damaged. One of the mechanical optimization methods it so add a built-in stabilizing mechanism. However, the performance of this supporting device becomes critical on certain flying heights, thus to avoid losing the drone. The paper is divided in two parts: the description of the gravitropism-like stabilizer and the diagnostic of its status using wavelet transformation and neural network classification.

The microtubule cytoskeleton does not integrate auxin transport and gravitropism in maize roots

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Hasenstein, K. H.; Blancaflor, E. B.; Lee, J. S.

1999-01-01

The Cholodny-Went hypothesis of gravitropism suggests that the graviresponse is controlled by the distribution of auxin. However, the mechanism of auxin transport during the graviresponse of roots is still unresolved. To determine whether the microtubule (MT) cytoskeleton is participating in auxin transport, the cytoskeleton was examined and the movement of 3H-IAA measured in intact and excised taxol, oryzalin, and naphthylphthalamic acid (NPA)-treated roots of Zea mays cv. Merit. Taxol and oryzalin did not inhibit the graviresponse of roots but the auxin transport inhibitor NPA greatly inhibited both auxin transport and graviresponse. NPA had no effect on MT organization in vertical roots, but caused MT reorientation in horizontally placed roots. Regardless of treatment, the organization of MTs in intact roots differed from that in root segments. The MT inhibitors, taxol and oryzalin had opposite effects on the MTs, namely, depolymerization (oryzalin) and stabilization and thickening (taxol), but both treatments caused swelling of the roots. The data indicate that the MT cytoskeleton does not directly interfere with auxin transport or auxin-mediated growth responses in maize roots.

Root growth, secondary root formation and root gravitropism in carotenoid-deficient seedlings of Zea mays L

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Ng, Y. K.; Moore, R.

1985-01-01

The effect of ABA on root growth, secondary-root formation and root gravitropism in seedlings of Zea mays was investigated by using Fluridone-treated seedlings and a viviparous mutant, both of which lack carotenoids and ABA. Primary roots of seedlings grown in the presence of Fluridone grew significantly slower than those of control (i.e. untreated) roots. Elongation of Fluridone-treated roots was inhibited significantly by the exogenous application of 1 mM ABA. Exogenous application of 1 micromole and 1 nmole ABA had either no effect or only a slight stimulatory effect on root elongation, depending on the method of application. The absence of ABA in Fluridone-treated plants was not an important factor in secondary-root formation in seedlings less than 9-10 d old. However, ABA may suppress secondary-root formation in older seedlings, since 11-d-old control seedlings had significantly fewer secondary roots than Fluridone-treated seedlings. Roots of Fluridone-treated and control seedlings were graviresponsive. Similar data were obtained for vp-9 mutants of Z. mays, which are phenotypically identical to Fluridone-treated seedlings. These results indicate that ABA is necessary for neither secondary-root formation nor for positive gravitropism by primary roots.

Exogenous hydrogen peroxide reversibly inhibits root gravitropism and induces horizontal curvature of primary root during grass pea germination.

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Jiang, Jinglong; Su, Miao; Wang, Liyan; Jiao, Chengjin; Sun, Zhengxi; Cheng, Wei; Li, Fengmin; Wang, Chongying

2012-04-01

During germination in distilled water (dH(2)O) on a horizontally positioned Petri dish, emerging primary roots of grass pea (Lathyrus sativus L.) grew perpendicular to the bottom of the Petri dish, due to gravitropism. However, when germinated in exogenous hydrogen peroxide (H(2)O(2)), the primary roots grew parallel to the bottom of the Petri dish and asymmetrically, forming a horizontal curvature. Time-course experiments showed that the effect was strongest when H(2)O(2) was applied prior to the emergence of the primary root. H(2)O(2) failed to induce root curvature when applied post-germination. Dosage studies revealed that the frequency of primary root curvature was significantly enhanced with increased H(2)O(2) concentrations. This curvature could be directly counteracted by dimethylthiourea (DMTU), a scavenger of H(2)O(2), but not by diphenylene iodonium (DPI) and pyridine, inhibitors of H(2)O(2) production. Exogenous H(2)O(2) treatment caused both an increase in the activities of H(2)O(2)-scavenging enzymes [including ascorbate peroxidase (APX: EC 1.11.1.11), catalase (CAT: EC 1.11.1.6) and peroxidase (POD: EC 1.11.1.7)] and a reduction in endogenous H(2)O(2) levels and root vitality. Although grass pea seeds absorbed exogenous H(2)O(2) during seed germination, DAB staining of paraffin sections revealed that exogenous H(2)O(2) only entered the root epidermis and not inner tissues. These data indicated that exogenously applied H(2)O(2) could lead to a reversible loss of the root gravitropic response and a horizontal curvature in primary roots during radicle emergence of the seedling. Copyright © 2012 Elsevier Masson SAS. All rights reserved.

Nature and origin of the calcium asymmetry-arising during gravitropic response in etiolated pea epicotyls

International Nuclear Information System (INIS)

Migliaccio, F.; Galston, A.W.

1987-01-01

Seven day old etiolated pea epicotyls were loaded symmetrically with 3 H-indole 3-acetic acid (IAA) or 45 Ca 2+ , then subjected to 1.5 hours of 1g gravistimulation. Epidermal peels taken from top and bottom surfaces after 90 minutes showed an increase in IAA on the lower side and of Ca 2+ on the upper side. Inhibitors of IAA movement (TIBA, 9-hydroxyfluorene carboxylic acid) block the development of both IAA and Ca 2+ asymmetries, but substances known to interfere with normal Ca 2+ transport do not significantly alter either IAA or Ca 2+ asymmetries. These substances, however, are active in modifying both Ca 2+ uptake and efflux through oat and pea leaf protoplast membranes. The authors conclude that the 45 Ca 2+ fed to pea epicotyls occurs largely in the cell wall, and that auxin movement is primary and Ca 2+ movement secondary in gravitropism. They hypothesize that apoplastic Ca 2+ changes during the graviresponse because it is displaced by H + secreted through auxin-induced proton release. This proposed mechanism is supported by localized pH experiments, in which filter paper soaked in various buffers was applied to one side of a carborundum-abraded epicotyls. Buffer at pH 3 increased calcium loss from the side to which it is applied, whereas pH 7 buffer decreases it. Moreover, 10 micromolar IAA and 1 micromolar fusicoccin, which promote H + efflux, increase Ca 2+ release from pea epicotyl segments, whereas cycloheximide, which inhibits H + efflux, has the reverse effect

ARG1 (altered response to gravity) encodes a DnaJ-like protein that potentially interacts with the cytoskeleton

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Sedbrook, J. C.; Chen, R.; Masson, P. H.

1999-01-01

Gravitropism allows plant organs to direct their growth at a specific angle from the gravity vector, promoting upward growth for shoots and downward growth for roots. Little is known about the mechanisms underlying gravitropic signal transduction. We found that mutations in the ARG1 locus of Arabidopsis thaliana alter root and hypocotyl gravitropism without affecting phototropism, root growth responses to phytohormones or inhibitors of auxin transport, or starch accumulation. The positional cloning of ARG1 revealed a DnaJ-like protein containing a coiled-coil region homologous to coiled coils found in cytoskeleton-interacting proteins. These data suggest that ARG1 participates in a gravity-signaling process involving the cytoskeleton. A combination of Northern blot studies and analysis of ARG1-GUS fusion-reporter expression in transgenic plants demonstrated that ARG1 is expressed in all organs. Ubiquitous ARG1 expression in Arabidopsis and the identification of an ortholog in Caenorhabditis elegans suggest that ARG1 is involved in other essential processes.

Real-Time Gas Identification by Analyzing the Transient Response of Capillary-Attached Conductive Gas Sensor

Directory of Open Access Journals (Sweden)

Behzad Bahraminejad

2010-05-01

Full Text Available In this study, the ability of the Capillary-attached conductive gas sensor (CGS in real-time gas identification was investigated. The structure of the prototype fabricated CGS is presented. Portions were selected from the beginning of the CGS transient response including the first 11 samples to the first 100 samples. Different feature extraction and classification methods were applied on the selected portions. Validation of methods was evaluated to study the ability of an early portion of the CGS transient response in target gas (TG identification. Experimental results proved that applying extracted features from an early part of the CGS transient response along with a classifier can distinguish short-chain alcohols from each other perfectly. Decreasing time of exposition in the interaction between target gas and sensing element improved the reliability of the sensor. Classification rate was also improved and time of identification was decreased. Moreover, the results indicated the optimum interval of the early transient response of the CGS for selecting portions to achieve the best classification rates.

Activated by Combined Magnrtic Field Gravitropic Reaction Reply on Nanodose of Biologicaly Active Compounds

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Sheykina, Nadezhda; Bogatina, Nina

The new science direction nanotechnologies initiated a big jump in the pharmacology and medicine. This leads to the big development of homeopathy. The most interest appeared while investigating of the reaction of biological object on the nano dose of iologically substances. The changing of concentration (in nmol/l) of biologically active material is also possible during weak energy action. For instance, weak combined magnetic field may change a little the concentration of ions that are oriented parallel to the external magnetic field and, by the analogy with said above, lead to the similar effects. Simple estimations give the value for the threshold to the magnetic field by two orders smaller than the geomagnetic field. By this investigation we wanted to understand whether the analogy in the action of nano dose of biologically active substances and weak combined magnetic field presents and whether the action of one of these factors may be replaced by other one. The effect of one of biologically active substances NPA (Naphtyl-Phtalame Acid) solution with the concentration 0.01 mol/l on the gravitropic reaction of cress roots was investigated. It was shown that its effect was the inhibition of cress roots gravitropic reaction. The same inhibition was achieved by the combined magnetic field action on the cress roots, germinated in water. The alternative component of the combined magnetic field coincided formally with the cyclotron frequency of NPA ions. So the analogy in the action of nano dose of biologically active substances and weak combined magnetic field was shown. The combined magnetic field using allows to decrease sufficiently the dose of biologically active substances. This fact can be of great importance in pharmacy and medicine.

Small RNA Deep Sequencing and the Effects of microRNA408 on Root Gravitropic Bending in Arabidopsis

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Li, Huasheng; Lu, Jinying; Sun, Qiao; Chen, Yu; He, Dacheng; Liu, Min

2015-11-01

MicroRNA (miRNA) is a non-coding small RNA composed of 20 to 24 nucleotides that influences plant root development. This study analyzed the miRNA expression in Arabidopsis root tip cells using Illumina sequencing and real-time PCR before (sample 0) and 15 min after (sample 15) a 3-D clinostat rotational treatment was administered. After stimulation was performed, the expression levels of seven miRNA genes, including Arabidopsis miR160, miR161, miR394, miR402, miR403, miR408, and miR823, were significantly upregulated. Illumina sequencing results also revealed two novel miRNAsthat have not been previously reported, The target genes of these miRNAs included pentatricopeptide repeat-containing protein and diadenosine tetraphosphate hydrolase. An overexpression vector of Arabidopsis miR408 was constructed and transferred to Arabidopsis plant. The roots of plants over expressing miR408 exhibited a slower reorientation upon gravistimulation in comparison with those of wild-type. This result indicate that miR408 could play a role in root gravitropic response.

Amyloplast displacement is necessary for gravisensing in Arabidopsis shoots as revealed by a centrifuge microscope.

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Toyota, Masatsugu; Ikeda, Norifumi; Sawai-Toyota, Satoe; Kato, Takehide; Gilroy, Simon; Tasaka, Masao; Morita, Miyo Terao

2013-11-01

The starch-statolith hypothesis proposes that starch-filled amyloplasts act as statoliths in plant gravisensing, moving in response to the gravity vector and signaling its direction. However, recent studies suggest that amyloplasts show continuous, complex movements in Arabidopsis shoots, contradicting the idea of a so-called 'static' or 'settled' statolith. Here, we show that amyloplast movement underlies shoot gravisensing by using a custom-designed centrifuge microscope in combination with analysis of gravitropic mutants. The centrifuge microscope revealed that sedimentary movements of amyloplasts under hypergravity conditions are linearly correlated with gravitropic curvature in wild-type stems. We next analyzed the hypergravity response in the shoot gravitropism 2 (sgr2) mutant, which exhibits neither a shoot gravitropic response nor amyloplast sedimentation at 1 g. sgr2 mutants were able to sense and respond to gravity under 30 g conditions, during which the amyloplasts sedimented. These findings are consistent with amyloplast redistribution resulting from gravity-driven movements triggering shoot gravisensing. To further support this idea, we examined two additional gravitropic mutants, phosphoglucomutase (pgm) and sgr9, which show abnormal amyloplast distribution and reduced gravitropism at 1 g. We found that the correlation between hypergravity-induced amyloplast sedimentation and gravitropic curvature of these mutants was identical to that of wild-type plants. These observations suggest that Arabidopsis shoots have a gravisensing mechanism that linearly converts the number of amyloplasts that settle to the 'bottom' of the cell into gravitropic signals. Further, the restoration of the gravitropic response by hypergravity in the gravitropic mutants that we tested indicates that these lines probably have a functional gravisensing mechanism that is not triggered at 1 g. © 2013 The Authors The Plant Journal © 2013 John Wiley & Sons Ltd.

Utilizing the response patterns of a temperature modulated chemoresistive gas sensor for gas diagnosis

International Nuclear Information System (INIS)

Amini, Amir; Ghafarinia, Vahid

2011-01-01

The observed features in the temporal response patterns of a temperature-modulated chemoresistive gas sensor were used for gas diagnosis. The patterns were recorded for clean air and air contaminated with different levels of some volatile organic compounds while a staircase heating voltage waveform had been applied to the microheater of a tin oxide gas sensor that modulated its operating temperature. Combining the steady-state and transient parameters of the recorded responses in the 50-400 deg. C range resulted in discriminatory feature vectors which were utilized for contaminant classification. The information content of these feature vectors was proved sufficient for discrimination of methanol, ethanol, 1-butanol, and acetone contaminations in a wide concentration range.

Utilizing the response patterns of a temperature modulated chemoresistive gas sensor for gas diagnosis

Energy Technology Data Exchange (ETDEWEB)

Amini, Amir [Jannatabad College, Sama Organization, Islamic Azad University, Tehran (Iran, Islamic Republic of); Ghafarinia, Vahid, E-mail: amir.amini.elec@gmail.com, E-mail: ghafarinia@ee.kntu.ac.ir [Electrical Engineering Department, K. N. Toosi University of Technology, Tehran (Iran, Islamic Republic of)

2011-02-15

The observed features in the temporal response patterns of a temperature-modulated chemoresistive gas sensor were used for gas diagnosis. The patterns were recorded for clean air and air contaminated with different levels of some volatile organic compounds while a staircase heating voltage waveform had been applied to the microheater of a tin oxide gas sensor that modulated its operating temperature. Combining the steady-state and transient parameters of the recorded responses in the 50-400 deg. C range resulted in discriminatory feature vectors which were utilized for contaminant classification. The information content of these feature vectors was proved sufficient for discrimination of methanol, ethanol, 1-butanol, and acetone contaminations in a wide concentration range.

Fuel switching? Demand destruction? Gas market responses to price spikes

International Nuclear Information System (INIS)

Lippe, D.

2004-01-01

This presentation defined fuel switching and addressed the issue regarding which consumers have the capability to switch fuels. In response to short term price aberrations, consumers with fuel switching capabilities reduce their use of one fuel and increase consumption of an alternative fuel. For example, natural gas consumption by some consumers declines in response to price spikes relative to prices of alternative fuels. This presentation also addressed the issue of differentiating between fuel switching and demand destruction. It also demonstrated how to compare gas prices versus alternative fuel prices and how to determine when consumers will likely switch fuels. Price spikes have implications for long term trends in natural gas demand, supply/demand balances and prices. The power generating sector represents a particular class of gas consumers that reduce operating rates of gas fired plants and increase operating rates of other plants. Some gas consumers even shut down plants until gas prices declines and relative economies improve. Some practical considerations for fuel switching include storage tank capacity, domestic refinery production, winter heating season, and decline in working gas storage. tabs., figs

Gravity response mechanisms of lateral organs and the control of plant architecture in Arabidopsis

Science.gov (United States)

Mullen, J.; Hangarter, R.

Most research on gravity responses in plants has focused on primary roots and shoots, which typically grow in a vertical orientation. However, the patterns of lateral organ formation and their growth orientation, which typically are not vertical, govern plant architecture. For example, in Arabidopsis, when lateral roots emerge from the primary root, they grow at a nearly horizontal orientation. As they elongate, the roots slowly curve until they eventually reach a vertical orientation. The regulation of this lateral root orientation is an important component affecting the overall root system architecture. We have found that this change in orientation is not simply due to the onset of gravitropic competence, as non-vertical lateral roots are capable of both positive and negative gravitropism. Thus, the horizontal growth of the new lateral roots is determined by what is called the gravitropic set-point angle (GSA). In Arabidopsis shoots, rosette leaves and inflorescence branches also display GSA-dependent developmental changes in their orientation. The developmental control of the GSA of lateral organs in Arabidopsis provides us with a useful system for investigating the components involved in regulating directionality of tropistic responses. We have identified several Arabidopsis mutants that have either altered lateral root orientations, altered orientation of lateral organs in the shoot, or both, but maintain normal primary organ orientation. The mgsa ({m}odified {g}ravitropic {s}et-point {a}ngle) mutants with both altered lateral root and shoot orientation show that there are common components in the regulation of growth orientation in the different organs. Rosette leaves and lateral roots also have in common a regulation of positioning by red light. Further molecular and physiological analyses of the GSA mutants will provide insight into the basis of GSA regulation and, thus, a better understanding of how gravity controls plant architecture. [This work was

Interactions between red light, abscisic acid, and calcium in gravitropism

Science.gov (United States)

Leopold, A. C.; LaFavre, A. K.

1989-01-01

The effect of red light on orthogravitropism of Merit corn (Zea mays L.) roots has been attributed to its effects on the transduction phase of gravitropism (AC Leopold, SH Wettlaufer [1988] Plant Physiol 87:803-805). In an effort to characterize the orthogravitropic transduction system, comparative experiments have been carried out on the effects of red light, calcium, and abscisic acid (ABA). The red light effect can be completely satisfied with added ABA (100 micromolar) or with osmotic shock, which is presumed to increase endogenous ABA. The decay of the red light effect is closely paralleled by the decay of the ABA effect. ABA and exogenous calcium show strong additive effects when applied to either Merit or a line of corn which does not require red light for orthogravitropism. Measurements of the ABA content show marked increases in endogenous ABA in the growing region of the roots after red light. The interpretation is offered that red light or ABA may serve to increase the cytoplasmic concentrations of calcium, and that this may be an integral part of orthogravitropic transduction.

An ABC transporter B family protein, ABCB19, is required for cytoplasmic streaming and gravitropism of the inflorescence stems.

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Okamoto, Keishi; Ueda, Haruko; Shimada, Tomoo; Tamura, Kentaro; Koumoto, Yasuko; Tasaka, Masao; Morita, Miyo Terao; Hara-Nishimura, Ikuko

2016-01-01

A significant feature of plant cells is the extensive motility of organelles and the cytosol, which was originally defined as cytoplasmic streaming. We suggested previously that a three-way interaction between plant-specific motor proteins myosin XIs, actin filaments, and the endoplasmic reticulum (ER) was responsible for cytoplasmic streaming. (1) Currently, however, there are no reports of molecular components for cytoplasmic streaming other than the actin-myosin-cytoskeleton and ER-related proteins. In the present study, we found that elongated cells of inflorescence stems of Arabidopsis thaliana exhibit vigorous cytoplasmic streaming. Statistical analysis showed that the maximal velocity of plastid movements is 7.26 µm/s, which is much faster than the previously reported velocities of organelles. Surprisingly, the maximal velocity of streaming in the inflorescence stem cells was significantly reduced to 1.11 µm/s in an Arabidopsis mutant, abcb19-101, which lacks ATP BINDING CASSETTE SUBFAMILY B19 (ABCB19) that mediates the polar transport of the phytohormone auxin together with PIN-FORMED (PIN) proteins. Polar auxin transport establishes the auxin concentration gradient essential for plant development and tropisms. Deficiency of ABCB19 activity eventually caused enhanced gravitropic responses of the inflorescence stems and abnormally flexed inflorescence stems. These results suggest that ABCB19-mediated auxin transport plays a role not only in tropism regulation, but also in cytoplasmic streaming.

Canadian Gas Association response to the Voluntary Challenge and Registry

International Nuclear Information System (INIS)

1996-11-01

Since the inception of Canada's Voluntary Challenge and Registry (VCR) program in 1994, the Canadian Gas Association (CGA) and its members have been active in promoting emissions reductions. Natural gas is considered to be one of the cleanest fossil fuels. However, the industry faces several challenges. Over 50 per cent of Canadian production is exported to the US, but no credits are being received to offset emission reduction in the US from fuel switching to natural gas. Also, more than 80 per cent of the emissions from the natural gas cycle occur at the burner tip, therefore users of natural gas must share the responsibility for reducing emissions through conservation practices and greater use of high-efficiency equipment. The activities undertaken by the CGA in response to the VCR program, including research and technology development were reviewed, and a forecast of future activities was presented. It was predicted that the demand for Canadian natural gas will exceed the historic rate of emissions reductions accomplished through energy conservation and efficiency improvements, hence there is likely to be an increase in net emissions. An argument was made to establish proxy indicators of success for the gas industry for VCR, such as emissions on a unit basis (unit of energy, production, throughput, etc.) to take into account the fact that the increase in natural gas demand is, in part, the result of fuel switching from more polluting fuels

The determination of frequency response function of the RSG Gas by laplace transform analysis

International Nuclear Information System (INIS)

Tukiran, S.; Surian, P.; Jujuratisbela, U.

1997-01-01

The response function of the RSG-GAS reactor system to the reactivity perturbations is necessary to be analyzed due to the interrelation with reliability and safety of reactor operation. the response depends on the power frequency response function H(s), while H(s) depends on the zero power frequency response function Z(s) and dynamic power coefficient of reactivity Kp(s) determination of the frequency response function of the RSG-GAS reactor was done by Fourier transform analysis method. Z(s) was obtained by fourier transform of P(t) and Cj(t) became P(S) and Cj(s) in point kinetic equations. Second order of simpson rule was used for completion of its numerical integration. then. LYMPR (Laplace transform for multipurpose reactor) code was made with fortran 77 computer language in vax 8550 system. the LTMPR code is able to determine the frequency response function and period-reactivity relation of RSG-GAS reactor by rod drop method. Profile of power as rod drop, zero power (without reactivity feedback) was used for determination frequency response of RSG-GAS reactor. The results of calculations are in a good agreement with experiment result, so the LTMPR code can be used for analysis response frequency of the RSG-GAS reactor

Collection of gravitropic effectors from mucilage of electrotropically-stimulated roots of Zea mays L

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Fondren, W. M.; Moore, R.

1987-01-01

We placed agar blocks adjacent to tips of electrotropically stimulated primary roots of Zea mays. Blocks placed adjacent to the anode-side of the roots for 3 h induced significant curvature when subsequently placed asymmetrically on tips of vertically-oriented roots. Curvature was always toward the side of the root unto which the agar block was placed. Agar blocks not contacting roots and blocks placed adjacent to the cathode-side of electrotropically stimulated roots did not induce significant curvature when placed asymmetrically on tips of vertically-oriented roots. Atomic absorption spectrophotometry indicated that blocks adjacent to the anode-side of electrotropically-stimulated roots contained significantly more calcium than (1) blocks not contacting roots, and (2) blocks contacting the cathode-side of roots. These results demonstrate the presence of a gradient of endogenous Ca in mucilage of electrotropically-stimulated roots (i.e. roots undergoing gravitropic-like curvature).

Delicate regulation of the cGAS-MITA-mediated innate immune response.

Science.gov (United States)

Luo, Wei-Wei; Shu, Hong-Bing

2018-02-19

Although it has long been demonstrated that cytosolic DNA is a potent immune stimulant, it is only in recent years that the molecular mechanisms of DNA-stimulated innate immune responses have emerged. Studies have established critical roles for the DNA sensor cyclic GMP-AMP synthase (cGAS) and the adapter protein MITA/STING in the innate immune response to cytosolic DNA or DNA viruses. Although the regulation of cGAS-MITA/STING-mediated signaling remains to be fully investigated, understanding the processes involved may help to explain the mechanisms of innate immune signaling events and perhaps autoinflammatory diseases and to provide potential therapeutic targets for drug intervention. In this review, we summarize recent progress on the regulation of the cGAS-MITA/STING-mediated innate immune response to DNA viruses at the organelle-trafficking, post-translational and transcriptional levels.Cellular & Molecular Immunology advance online publication, 19 February 2018; doi:10.1038/cmi.2016.51.

cGAS-mediated control of blood-stage malaria promotes Plasmodium-specific germinal center responses.

Science.gov (United States)

Hahn, William O; Butler, Noah S; Lindner, Scott E; Akilesh, Holly M; Sather, D Noah; Kappe, Stefan Hi; Hamerman, Jessica A; Gale, Michael; Liles, W Conrad; Pepper, Marion

2018-01-25

Sensing of pathogens by host pattern recognition receptors is essential for activating the immune response during infection. We used a nonlethal murine model of malaria (Plasmodium yoelii 17XNL) to assess the contribution of the pattern recognition receptor cyclic GMP-AMP synthase (cGAS) to the development of humoral immunity. Despite previous reports suggesting a critical, intrinsic role for cGAS in early B cell responses, cGAS-deficient (cGAS-/-) mice had no defect in the early expansion or differentiation of Plasmodium-specific B cells. As the infection proceeded, however, cGAS-/- mice exhibited higher parasite burdens and aberrant germinal center and memory B cell formation when compared with littermate controls. Antimalarial drugs were used to further demonstrate that the disrupted humoral response was not B cell intrinsic but instead was a secondary effect of a loss of parasite control. These findings therefore demonstrate that cGAS-mediated innate-sensing contributes to parasite control but is not intrinsically required for the development of humoral immunity. Our findings highlight the need to consider the indirect effects of pathogen burden in investigations examining how the innate immune system affects the adaptive immune response.

Response mechanism for surface acoustic wave gas sensors based on surface-adsorption.

Science.gov (United States)

Liu, Jiansheng; Lu, Yanyan

2014-04-16

A theoretical model is established to describe the response mechanism of surface acoustic wave (SAW) gas sensors based on physical adsorption on the detector surface. Wohljent's method is utilized to describe the relationship of sensor output (frequency shift of SAW oscillator) and the mass loaded on the detector surface. The Brunauer-Emmett-Teller (BET) formula and its improved form are introduced to depict the adsorption behavior of gas on the detector surface. By combining the two methods, we obtain a theoretical model for the response mechanism of SAW gas sensors. By using a commercial SAW gas chromatography (GC) analyzer, an experiment is performed to measure the frequency shifts caused by different concentration of dimethyl methylphosphonate (DMMP). The parameters in the model are given by fitting the experimental results and the theoretical curve agrees well with the experimental data.

Apoplastic pH in corn root gravitropism: a laser scanning confocal microscopy measurement

International Nuclear Information System (INIS)

Taylor, D.P.; Slattery, J.; Leopold, A.C.

1996-01-01

The ability to measure the pH of the apoplast in situ is of special interest as a test of the cell wall acidification theory. Optical sectioning of living seedlings of corn roots using the laser scanning confocal microscope (LSCM) permits us to make pH measurements in living tissue. The pH of the apoplast of corn roots was measured by this method after infiltration with CI-NERF, a pH-sensitive dye, along with Texas Red Dextran 3000, a pH-insensitive dye, as an internal standard. In the elongation zone of corn roots, the mean apoplastic pH was 4.9. Upon gravitropic stimulation, the pH on the convex side of actively bending roots was 4.5. The lowering of the apoplastic pH by 0.4 units appears to be sufficient to account for the increased growth on that side. This technique provides site-specific evidence for the acid growth theory of cell elongation. The LSCM permits measurements of the pH of living tissues, and has a sensitivity of approximately 0.2 pH units. (author)

Fast response time alcohol gas sensor using nanocrystalline F

Indian Academy of Sciences (India)

Home; Journals; Bulletin of Materials Science; Volume 36; Issue 4. Fast response time alcohol gas sensor using nanocrystalline F-doped SnO2 films derived via sol–gel method. Sarbani Basu Yeong-Her Wang C Ghanshyam Pawan Kapur. Volume 36 Issue 4 August 2013 pp 521-533 ...

A structural comparison of the responses of US natural gas models

International Nuclear Information System (INIS)

Huntington, H.G.

1989-01-01

The EMF 9 scenarios were designed to elicit insights about possible future natural gas market conditions under alternative resource, demand, and oil price trends. These cases are also useful for probing the models themselves because the reported results for the different scenarios reveal important information about the behavioral responses represented in each model. This paper compares these responses in order to explain why they differ and what are the implications of these differences for analyzing gas markets. The integrating framework for this model comparison is a rudimentary supply-demand analysis of market forces that has been successfully applied to many commodity markets. A central theme in this approach is that supply and demand imbalances will eventually be rectified through an adjustment in prices that eliminates excess supply or demand. While this approach abstracts from the important regulatory and institutional constraints, it focuses attention on the growing importance of price determination in a gas market that has fast become integrated nationally as well as internationally. The recently signed and ratified Canadian-US Free Trade Agreement commits both governments not to restrict energy imports or exports or to impose minimum export price requirements, except under special conditions. As competitive forces become more important within the gas industry, this paradigm appears appropriate for probing key long-term relationships critical to this fuel's future. This paper focuses on the responses in total consumption, production, average wellhead price, and average delivered price in the United States for the eight models reporting these variables. Results are reported for 2000, which represent mid- to long-term adjustments for the most part. Responses for other years are shown in Appendix B and those for Canada in Appendix D

Effect of gas pressure on active screen plasma nitriding response

International Nuclear Information System (INIS)

Nishimoto, Akio; Nagatsuka, Kimiaki; Narita, Ryota; Nii, Hiroaki; Akamatsu, Katsuya

2010-01-01

An austenitic stainless steel AISI 304 was active screen plasma nitrided using a 304 steel screen to investigate the effect of the gas pressure on the ASPN response. The sample was treated for 18 ks at 723 K in 25% N2 + 75% H2 gases. The gas pressure was changed to 100, 600 and 1200 Pa. The distance between screen and sample was also changed to 10, 30 and 50 mm. The nitrided samples were characterized by appearance observation, surface roughness, optical microscopy, X-ray diffraction, and microhardness testing. After nitriding, polygonal particles with a normal distribution were observed at the center and edges of all the ASPN-treated sample surfaces. Particles on the sample surfaces were finer with an increase in the gas pressure. The nitrided layer with a greater and homogeneous thickness was obtained at a low gas pressure of 100 Pa. (author)

Rhizoids and protonemata of characean algae: model cells for research on polarized growth and plant gravity sensing.

Science.gov (United States)

Braun, M; Limbach, C

2006-12-01

Gravitropically tip-growing rhizoids and protonemata of characean algae are well-established unicellular plant model systems for research on gravitropism. In recent years, considerable progress has been made in the understanding of the cellular and molecular mechanisms underlying gravity sensing and gravity-oriented growth. While in higher-plant statocytes the role of cytoskeletal elements, especially the actin cytoskeleton, in the mechanisms of gravity sensing is still enigmatic, there is clear evidence that in the characean cells actin is intimately involved in polarized growth, gravity sensing, and the gravitropic response mechanisms. The multiple functions of actin are orchestrated by a variety of actin-binding proteins which control actin polymerisation, regulate the dynamic remodelling of the actin filament architecture, and mediate the transport of vesicles and organelles. Actin and a steep gradient of cytoplasmic free calcium are crucial components of a feedback mechanism that controls polarized growth. Experiments performed in microgravity provided evidence that actomyosin is a key player for gravity sensing: it coordinates the position of statoliths and, upon a change in the cell's orientation, directs sedimenting statoliths to specific areas of the plasma membrane, where contact with membrane-bound gravisensor molecules elicits short gravitropic pathways. In rhizoids, gravitropic signalling leads to a local reduction of cytoplasmic free calcium and results in differential growth of the opposite subapical cell flanks. The negative gravitropic response of protonemata involves actin-dependent relocation of the calcium gradient and displacement of the centre of maximal growth towards the upper flank. On the basis of the results obtained from the gravitropic model cells, a similar fine-tuning function of the actomyosin system is discussed for the early steps of gravity sensing in higher-plant statocytes.

Emergency Response Program Designing Based On Case Study ERP Regulations In Ilam Gas Refinery

Directory of Open Access Journals (Sweden)

Mehdi Tahmasbi

2015-08-01

Full Text Available The study of Emergency response plan designing is one of the most important prevention approaches in crisis management. This study aims to design emergency response plan based on case study ERP regulations in Ilam gas refinery. On the basis of risk assessment and identification techniques such as HAZOP and FMEA in Ilam gas refinery the risks have been prioritized and then according to this prioritization the design of possible scenarios which have the highest rate of occurrence and the highest level of damage has been separated. Possible scenarios were simulated with PHAST software. Then emergency response program has been designed for the special mode or similar cases. According to the internal emergency response plan for Ilam gas refinery and predictable conditions of the process special instructions should be considered at the time of the incident to suffer the least damage on people and environment in the shortest time possible.

The E3 ubiquitin ligase RNF185 facilitates the cGAS-mediated innate immune response.

Directory of Open Access Journals (Sweden)

Qiang Wang

2017-03-01

Full Text Available The cyclic GMP-AMP synthase (cGAS, upon cytosolic DNA stimulation, catalyzes the formation of the second messenger 2'3'-cGAMP, which then binds to stimulator of interferon genes (STING and activates downstream signaling. It remains to be elucidated how the cGAS enzymatic activity is modulated dynamically. Here, we reported that the ER ubiquitin ligase RNF185 interacted with cGAS during HSV-1 infection. Ectopic-expression or knockdown of RNF185 respectively enhanced or impaired the IRF3-responsive gene expression. Mechanistically, RNF185 specifically catalyzed the K27-linked poly-ubiquitination of cGAS, which promoted its enzymatic activity. Additionally, Systemic Lupus Erythematosus (SLE patients displayed elevated expression of RNF185 mRNA. Collectively, this study uncovers RNF185 as the first E3 ubiquitin ligase of cGAS, shedding light on the regulation of cGAS activity in innate immune responses.

Future arrangements for Great Britain's gas quality specifications. Government Response (including Summary of Responses) to consultation on future arrangements for Great Britain's gas quality specifications

International Nuclear Information System (INIS)

2007-01-01

Last year the Government consulted on GB's future gas quality specifications. The background is that some streams of imported gases have an energy content that exceeds the upper limit specified in GB's current gas quality regulations. The policy issue was whether to stick with the current regulated specifications, but at the cost of having to process imported gas to bring it within those specifications; or, at some time after 2020, to adjust those specifications, but at the cost of having to check (and potentially change) approximately 45m domestic gas appliances in 22m households, to ensure that they are capable of burning the high energy gas safely (and with a residual safety risk that some appliances are missed). The Consultation Document sought views on the proposal (backed up by the Partial Regulatory Impact Assessment) to adopt the 'no change' option. In the light of the responses, this is what the Government now proposes. The associated Impact Assessment estimates the total net benefit of the 'no change' option at UK Pounds 1.5bn - 14bn, with a best estimate of UK Pounds 8bn (NPV, 2005). The risks for gas prices and security of supply (included in the Impact Assessment) are judged to be small. The Government proposes a 'forward plan', consisting of support for Ofgem's work on maximising the commercial flexibilities for the GB gas market to handle gases of different specifications, whilst continuing to engage in EU discussions on the gas quality issue. (Author)

Activation of cGAS-dependent antiviral responses by DNA intercalating agents.

Science.gov (United States)

Pépin, Geneviève; Nejad, Charlotte; Thomas, Belinda J; Ferrand, Jonathan; McArthur, Kate; Bardin, Philip G; Williams, Bryan R G; Gantier, Michael P

2017-01-09

Acridine dyes, including proflavine and acriflavine, were commonly used as antiseptics before the advent of penicillins in the mid-1940s. While their mode of action on pathogens was originally attributed to their DNA intercalating activity, work in the early 1970s suggested involvement of the host immune responses, characterized by induction of interferon (IFN)-like activities through an unknown mechanism. We demonstrate here that sub-toxic concentrations of a mixture of acriflavine and proflavine instigate a cyclic-GMP-AMP (cGAMP) synthase (cGAS)-dependent type-I IFN antiviral response. This pertains to the capacity of these compounds to induce low level DNA damage and cytoplasmic DNA leakage, resulting in cGAS-dependent cGAMP-like activity. Critically, acriflavine:proflavine pre-treatment of human primary bronchial epithelial cells significantly reduced rhinovirus infection. Collectively, our findings constitute the first evidence that non-toxic DNA binding agents have the capacity to act as indirect agonists of cGAS, to exert potent antiviral effects in mammalian cells. © The Author(s) 2016. Published by Oxford University Press on behalf of Nucleic Acids Research.

Response of Elk to Habitat Modification Near Natural Gas Development

Science.gov (United States)

Van Dyke, Fred; Fox, Autumn; Harju, Seth M.; Dzialak, Matthew R.; Hayden-Wing, Larry D.; Winstead, Jeffrey B.

2012-11-01

Elk (Cervus elaphus) are known to shift habitat use in response to environmental modifications, including those associated with various forms of energy development. The specific behavioral responses underlying these trends, however, have not been effectively studied. To investigate such effects, we examined elk response to habitat alteration near natural gas wells in Las Animas County, Colorado, USA in 2008-2010. We created 10 1-ha openings in forests adjacent to 10 operating natural gas wells by removing standing timber in 2008, with concomitant establishment of 10 1-ha control sites adjacent to the same wells. On each site, we estimated elk use, indexed by pellet density, before and after timber removal. Concurrently, we measured plant production and cover, nutritional quality, species composition and biomass removed by elk and other large herbivores. Species richness and diversity, graminoid and forb cover, and graminoid and forb biomass increased on cut sites following tree removal. Differences were greater in 2010 than in 2009, and elk and deer removed more plant biomass in 2010 than 2009. Elk use of cut sites was 37 % lower than control sites in 2009, but 46 % higher in 2010. The initially lower use of cut sites may be attributable to lack of winter forage on these sites caused by timber removal and associated surface modification. The increased use of cut sites in 2010 suggested that elk possessed the behavioral capacity, over time, to exploit enhanced forage resources in the proximity of habitat modifications and human activity associated with maintenance of operating natural gas wells.

The Relationship Between Oil and Gas Industry Investment in Alternative Energy and Corporate Social Responsibility

Science.gov (United States)

Konyushikhin, Maxim

The U.S. Energy Information Administration forecasted energy consumption in the United States to increase approximately 19% between 2006 and 2030, or about 0.7% annually. The research problem addressed in this study was that the oil and gas industry's interest in alternative energy is contrary to its current business objectives and profit goals. The purpose of the quantitative study was to explore the relationship between oil and gas industry investments in alternative energy and corporate social responsibilities. Research questions addressed the relationship between alternative energy investment and corporate social responsibility, the role of oil and gas companies in alternative energy investment, and why these companies chose to invest in alternative energy sources. Systems theory was the conceptual framework, and data were collected from a sample of 25 companies drawn from the 28,000 companies in the oil and gas industry from 2004 to 2009. Multiple regression and correlation analysis were used to answer the research questions and test hypotheses using corporate financial data and company profiles related to alternative energy investment and corporate social responsibility in terms of oil and gas industry financial support of programs that serve the greater social good. Results indicated significant relationships between alternative energy investment and corporate social responsibility. With an increasing global population with energy requirements in excess of what is available using traditional means, the industry should increase investment in alternative sources. The research results may promote positive social change by increasing public awareness regarding the degree to which oil and gas companies invest in developing alternative energy sources, which might, in turn, inspire public pressure on companies in the oil and gas industry to pursue use of alternative energy.

Reducing pollution at five critical points of shale gas production: Strategies and institutional responses

International Nuclear Information System (INIS)

Centner, Terence J.

2016-01-01

While the public and governments debate the advisability of engaging in shale gas production, the United States has proceeded to develop its resources with an accompanying remarkable increase in natural gas production. The development of shale gas has not been without problems, and some countries have decided that shale gas production should not proceed until more is known about the accompanying health issues and environmental damages. From experiences in the United States, careful consideration of five critical points relating to shale gas production can form the basis for developing strategies for reducing discharges of pollutants: (1) casing and cementing, (2) handling wastewater, (3) venting and flaring, (4) equipment with air emissions, and (5) seismic events. For each strategy, institutional responses to markedly reduce the risks of harm to people and the environment are identified. These responses offer state and local governments ideas for enabling shale gas resources to be developed without sacrificing public health and environmental quality. - Highlights: •Shale gas development involves releases of unnecessary pollutants. •Major sources of unnecessary pollutants can be identified. •For major pollutant sources, strategies can be developed to reduce releases of contaminants. •Alternative strategies can offer firms and governments ways to reduce pollutant releases.

Optical Response of Poly (1,4-Phenylene-1,2-Di (P-Phenoxyphenyl Vinylene Towards Oxygen Gas

Directory of Open Access Journals (Sweden)

F.S Mehamod

2017-10-01

with terephthaloydichloride and biphenylether as starting materials and anhydrous AlCl3 as the catalyst, while the dpop-PDV was synthesized via the McMurry coupling reaction. The polymerization was carried out in THF with TiCl4 and Zn as the catalyst and reducing agent respectively. Characterization on monomer and polymer had been carried out by using FTIR, GCMS, DSC, TGA, GPC and melting point measurement. Response of the polymer towards oxygen gas was described in terms of fluorescence spectra, repeatability, reproducibility and the response curve. Results obtained showed that the fluorescence intensity decreased upon exposure to O2 gas, indicating that the polymer was responsive to the presence of the O2 gas and the sample was found regenerable by flushing the polymer solution with N2 gas.

Changes in root gravitropism, ultrastructure, and calcium balance of pea root statocytes induced by A23187

Science.gov (United States)

Belyavskaya, N.

The role for calcium in the regulation of a wide variety of cellular events in plants is well known. Calcium signaling has been implicated in plant gravitropism. A carboxylic acid antibiotic A23187 (calcimycin) has been widely used in biological studies since it can translocate calcium across membranes. Seedlings of Pisum sativum L. cv. Uladovsky germinated in a vertically oriented cylinder of moist filter paper soaked in water during 4.5 day had been treated with 10-5 M A23187 for 12 hr. Tips of primary roots of control and A23187-treated pea seedlings were fixed for electron microscopy and electron cytochemistry. Experiments with Pisum sativum 5- day seedlings placed horizontally for 4 h after treatment with 10 μM A23187 during 12 h found that the graviresponsiveness of their primary roots was lost completely (91 % of roots) or inhibited (24 +/- 6° in comparison with 88 +/- 8° in control). At ultrastructural level, there were observed distribution of amyloplasts around the nucleus, remarkable lengthening of statocytes, advanced vacuolization, changes in dictyosome structure, ER fragmentation, cell wall thinning in A23187-treated statocytes. Cytochemical study has indicated that statocytes exposed to calcimycin have contained a number of Ca-pyroantimonate granules detected Ca 2 + ions in organelles and hyaloplasm (unlike the control ones). The deposits were mainly associated with the plasma membrane. Among organelles, mitochondria were notable for their ability to accumulate Ca 2 +. In amyloplasts, a fine precipitate was predominately located in their stroma and envelope lumens. In cell walls, deposits of the reaction product were observed along the periphery and in the median zone. Localization of electron-dense granules of lead phosphate, which indicated Ca 2 +- ATPase activities in pea statocytes exposed to A23187, was generally consistent with that in untreated roots. Apart from plasma membrane, chromatin, and nucleolus components, the cytochemical reaction

Extraction of diagnostic parameters from the transient response of a porous electro ceramic gas sensor

International Nuclear Information System (INIS)

Hossein-Babaei, F.; Orvatinia, M.

2004-01-01

A novel concept for the diagnosis of a pure target gas in air is presented. The method employs a resistive gas sensor with a mm-thick highly porous electro ceramic gas sensitive body. The diagnosis is based on the fact that the diffusion time of the target gas through the porous body would depend on its molecular properties. The transient response of the device was analyzed based on a diffusion reaction equation. The solutions of the equation were shown to be of diagnostic merits. Such a device was fabricated by partial sintering of a Zn O body formed by low pressure pressing. The transient responses of the device to methanol, ethanol, poropanol and butanol were recorded. The analytical data, and the diagnostic parameters were resulted as the fitting parameters. Comparison of the parameters obtained with those available from the calibration experiments afforded target gas identification

Gravimorphism in rice and barley: promotion of leaf elongation by vertical inversion in agravitropically growing plants.

Science.gov (United States)

Abe, K; Takahashi, H; Suge, H

1998-12-01

We have compared shoot responses of agravitropic rice and barley plants to vertical inversion with those of normal ones. When rice plants were vertically inverted, the main stems of a japonica type of rice, cv. Kamenoo, showed negative gravitropism at nodes 2-15 of both elongated and non-elongated internodes. However, shoots of lazy line of rice, lazy-Kamenoo, bent gravitropically at nodes 11-15 only elongated internodes but not at nodes 2-10 of non-elongated ones. Thus, shoots of Kamenoo responded gravitropically at all stages of growth, whereas shoots of lazy-Kamenoo did not show gravitropic response before heading. In Kamenoo plants, lengths of both leaf-sheath and leaf-blade were shortened by vertical inversion, but those of the vertically inverted plants of lazy-Kamenoo were significantly longer than the plants in an upright position. When agravitropic and normal plants of barley were vertically inverted, the same results as in rice were obtained; elongation of both leaf-sheath and leaf-blade was inhibited in normal barley plants, Chikurin-Ibaragi No. 1, but significantly stimulated in agravitropic plants of serpentina barley. These results suggest that vertical inversion of rice and barley plants enhances the elongation growth of leaves in the absence of tropistic response.

Changes in root cap pH are required for the gravity response of the Arabidopsis root

Science.gov (United States)

Fasano, J. M.; Swanson, S. J.; Blancaflor, E. B.; Dowd, P. E.; Kao, T. H.; Gilroy, S.

2001-01-01

Although the columella cells of the root cap have been identified as the site of gravity perception, the cellular events that mediate gravity signaling remain poorly understood. To determine if cytoplasmic and/or wall pH mediates the initial stages of root gravitropism, we combined a novel cell wall pH sensor (a cellulose binding domain peptide-Oregon green conjugate) and a cytoplasmic pH sensor (plants expressing pH-sensitive green fluorescent protein) to monitor pH dynamics throughout the graviresponding Arabidopsis root. The root cap apoplast acidified from pH 5.5 to 4.5 within 2 min of gravistimulation. Concomitantly, cytoplasmic pH increased in columella cells from 7.2 to 7.6 but was unchanged elsewhere in the root. These changes in cap pH preceded detectable tropic growth or growth-related pH changes in the elongation zone cell wall by 10 min. Altering the gravity-related columella cytoplasmic pH shift with caged protons delayed the gravitropic response. Together, these results suggest that alterations in root cap pH likely are involved in the initial events that mediate root gravity perception or signal transduction.

Localization of cells containing sedimented amyloplasts in the shoots of normal and lazy rice seedlings.

Science.gov (United States)

Abe, K; Takahashi, H; Suge, H

1994-12-01

We have examined the localization of the cells containing sedimented amyloplasts (putative statocytes) and its relation to the graviresponding sites in the shoots of normal and lazy rice seedlings. All graviresponsive organs of the shoots of normal rice seedlings, the mesocotyl, the coleoptile and the leaf-sheath base, were found to possess the statocytes. This is the first indication that mesocotyl senses gravity by its own cells in inducing gravitropic bending in rice seedlings. In lazy-Kamenoo, although the shoots lost their gravitropic response with the advance of age, sedimentation of amyloplasts itself might not be attributable to the agravitropic growth of the shoots, because, including those of the leaf-sheath bases that had lost their response to gravity, sedimented amyloplasts appeared to be identical to those of normal Kamenoo and of younger seedlings of lazy-Kamenoo whose gravitropism is still apparent.

Novel gas sensor with dual response under CO(g) exposure: Optical and electrical stimuli

Science.gov (United States)

Rocha, L. S. R.; Cilense, M.; Ponce, M. A.; Aldao, C. M.; Oliveira, L. L.; Longo, E.; Simoes, A. Z.

2018-05-01

In this work, a lanthanum (La) doped ceria (CeO2) film, which depicted a dual gas sensing response (electric and optical) for CO(g) detection, was obtained by the microwave-assisted hydrothermal (HAM) synthesis and deposited by the screen-printing technique, in order to prevent deaths by intoxication with this life-threatening gas. An electric response under CO(g) exposure was obtained, along with an extremely fast optical response for a temperature of 380 °C, associated with Ce+4 reduction and vacancy generation. A direct optical gap was found to be around 2.31 eV from UV-Vis results, which corresponds to a transition from valence band to 4f states. Due to the anomalous electron configuration of cerium atoms with 4f electrons in its reduced state, they are likely to present an electric conduction based on the small polaron theory with a hopping mechanism responsible for its dual sensing response with a complete reversible behaviour.

Towards systems biology of the gravity response of higher plants -multiscale analysis of Arabidopsis thaliana root growth

Science.gov (United States)

Palme, Klaus; Aubry, D.; Bensch, M.; Schmidt, T.; Ronneberger, O.; Neu, C.; Li, X.; Wang, H.; Santos, F.; Wang, B.; Paponov, I.; Ditengou, F. A.; Teale, W. T.; Volkmann, D.; Baluska, F.; Nonis, A.; Trevisan, S.; Ruperti, B.; Dovzhenko, A.

Gravity plays a fundamental role in plant growth and development. Up to now, little is known about the molecular organisation of the signal transduction cascades and networks which co-ordinate gravity perception and response. By using an integrated systems biological approach, a systems analysis of gravity perception and the subsequent tightly-regulated growth response is planned in the model plant Arabidopsis thaliana. This approach will address questions such as: (i) what are the components of gravity signal transduction pathways? (ii) what are the dynamics of these components? (iii) what is their spatio-temporal regulation in different tis-sues? Using Arabidopsis thaliana as a model-we use root growth to obtain insights in the gravity response. New techniques enable identification of the individual genes affected by grav-ity and further integration of transcriptomics and proteomics data into interaction networks and cell communication events that operate during gravitropic curvature. Using systematic multiscale analysis we have identified regulatory networks consisting of transcription factors, the protein degradation machinery, vesicle trafficking and cellular signalling during the gravire-sponse. We developed approach allowing to incorporate key features of the root system across all relevant spatial and temporal scales to describe gene-expression patterns and correlate them with individual gene and protein functions. Combination of high-resolution microscopy and novel computational tools resulted in development of the root 3D model in which quantitative descriptions of cellular network properties and of multicellular interactions important in root growth and gravitropism can be integrated for the first time.

Functionalised zinc oxide nanowire gas sensors: Enhanced NO(2) gas sensor response by chemical modification of nanowire surfaces.

Science.gov (United States)

Waclawik, Eric R; Chang, Jin; Ponzoni, Andrea; Concina, Isabella; Zappa, Dario; Comini, Elisabetta; Motta, Nunzio; Faglia, Guido; Sberveglieri, Giorgio

2012-01-01

Surface coating with an organic self-assembled monolayer (SAM) can enhance surface reactions or the absorption of specific gases and hence improve the response of a metal oxide (MOx) sensor toward particular target gases in the environment. In this study the effect of an adsorbed organic layer on the dynamic response of zinc oxide nanowire gas sensors was investigated. The effect of ZnO surface functionalisation by two different organic molecules, tris(hydroxymethyl)aminomethane (THMA) and dodecanethiol (DT), was studied. The response towards ammonia, nitrous oxide and nitrogen dioxide was investigated for three sensor configurations, namely pure ZnO nanowires, organic-coated ZnO nanowires and ZnO nanowires covered with a sparse layer of organic-coated ZnO nanoparticles. Exposure of the nanowire sensors to the oxidising gas NO(2) produced a significant and reproducible response. ZnO and THMA-coated ZnO nanowire sensors both readily detected NO(2) down to a concentration in the very low ppm range. Notably, the THMA-coated nanowires consistently displayed a small, enhanced response to NO(2) compared to uncoated ZnO nanowire sensors. At the lower concentration levels tested, ZnO nanowire sensors that were coated with THMA-capped ZnO nanoparticles were found to exhibit the greatest enhanced response. ΔR/R was two times greater than that for the as-prepared ZnO nanowire sensors. It is proposed that the ΔR/R enhancement in this case originates from the changes induced in the depletion-layer width of the ZnO nanoparticles that bridge ZnO nanowires resulting from THMA ligand binding to the surface of the particle coating. The heightened response and selectivity to the NO(2) target are positive results arising from the coating of these ZnO nanowire sensors with organic-SAM-functionalised ZnO nanoparticles.

cGAS Senses Human Cytomegalovirus and Induces Type I Interferon Responses in Human Monocyte-Derived Cells.

Directory of Open Access Journals (Sweden)

Jennifer Paijo

2016-04-01

Full Text Available Human cytomegalovirus (HCMV infections of healthy individuals are mostly unnoticed and result in viral latency. However, HCMV can also cause devastating disease, e.g., upon reactivation in immunocompromised patients. Yet, little is known about human immune cell sensing of DNA-encoded HCMV. Recent studies indicated that during viral infection the cyclic GMP/AMP synthase (cGAS senses cytosolic DNA and catalyzes formation of the cyclic di-nucleotide cGAMP, which triggers stimulator of interferon genes (STING and thus induces antiviral type I interferon (IFN-I responses. We found that plasmacytoid dendritic cells (pDC as well as monocyte-derived DC and macrophages constitutively expressed cGAS and STING. HCMV infection further induced cGAS, whereas STING expression was only moderately affected. Although pDC expressed particularly high levels of cGAS, and the cGAS/STING axis was functional down-stream of STING, as indicated by IFN-I induction upon synthetic cGAMP treatment, pDC were not susceptible to HCMV infection and mounted IFN-I responses in a TLR9-dependent manner. Conversely, HCMV infected monocyte-derived cells synthesized abundant cGAMP levels that preceded IFN-I production and that correlated with the extent of infection. CRISPR/Cas9- or siRNA-mediated cGAS ablation in monocytic THP-1 cells and primary monocyte-derived cells, respectively, impeded induction of IFN-I responses following HCMV infection. Thus, cGAS is a key sensor of HCMV for IFN-I induction in primary human monocyte-derived DC and macrophages.

Gas priority users consultation : government response

International Nuclear Information System (INIS)

2007-01-01

This consultation document presents the results of an updated analysis of gas priority users comments on the UK government's proposals for updating the current priority lists, amending the eligibility criteria for priority user status, and simplifying the administration of the scheme. The extension of Category C priority users to include sites where interruption of gas supplies would lead to damage exceeding fifty million pounds to a plant at another site is discussed. It is acknowledged that there is a preference for a reduction of gas demand as opposed to a cessation in the case of an emergency gas supply deficit and details are given of a Task Group set up to examine options for reducing demand rather than cessation for large industrial gas users. The role of the Network Emergency Co-ordinator, support for a more flexible approach, pre-agreed rota interruption, a long-duration emergency, demand reduction, and the establishment of a Government/Industry Gas/Electricity Task Group are discussed, and the raising of the load shedding threshold of 25,000 therms/yr is considered

Response Functions for the Two-Dimensional Ultracold Fermi Gas: Dynamical BCS Theory and Beyond

Science.gov (United States)

Vitali, Ettore; Shi, Hao; Qin, Mingpu; Zhang, Shiwei

2017-12-01

Response functions are central objects in physics. They provide crucial information about the behavior of physical systems, and they can be directly compared with scattering experiments involving particles such as neutrons or photons. Calculations of such functions starting from the many-body Hamiltonian of a physical system are challenging and extremely valuable. In this paper, we focus on the two-dimensional (2D) ultracold Fermi atomic gas which has been realized experimentally. We present an application of the dynamical BCS theory to obtain response functions for different regimes of interaction strengths in the 2D gas with zero-range attractive interaction. We also discuss auxiliary-field quantum Monte Carlo (AFQMC) methods for the calculation of imaginary time correlations in these dilute Fermi gas systems. Illustrative results are given and comparisons are made between AFQMC and dynamical BCS theory results to assess the accuracy of the latter.

A simulation model for transient response of a gas separation module using a hollow fiber membrane

Energy Technology Data Exchange (ETDEWEB)

Sugiyama, Takahiko, E-mail: t-sugiyama@nucl.nagoya-u.ac.jp [Nagoya University, Fro-cho, Chikusa-ku, Nagoya 464-8603 (Japan); Miyahara, Naoya [Nagoya University, Fro-cho, Chikusa-ku, Nagoya 464-8603 (Japan); Tanaka, Masahiro [National Institute for Fusion Science, Oroshi-cho 322-6, Toki 509-5292 (Japan); Munakata, Kenzo [Akita University, Tegata Gakuen-cho 1-1, Akita-shi, Akita 010-8502 (Japan); Yamamoto, Ichiro [Nagoya University, Fro-cho, Chikusa-ku, Nagoya 464-8603 (Japan)

2011-10-15

A simulation model has been developed for transient response of a gas separation module using a hollow fiber membrane for the removal of tritium from the atmosphere of the confinement space. The mass transfer process such as sorption and desorption of gases at the surface of the dense layer and the porous support layer, diffusive transfer in the both layers are treated in the model. Sorption isotherm, mass transfer rate and permeance are estimated through step-wise transient response experiments. The present model represents well not only separation factors and recovery ratio at the steady state but also responses to the multi-step wise change in the sweep gas rate.

Functional Analysis of the Arabidopsis thaliana CDPK-Related Kinase Family: AtCRK1 Regulates Responses to Continuous Light

Directory of Open Access Journals (Sweden)

Abu Imran Baba

2018-04-01

Full Text Available The Calcium-Dependent Protein Kinase (CDPK-Related Kinase family (CRKs consists of eight members in Arabidopsis. Recently, AtCRK5 was shown to play a direct role in the regulation of root gravitropic response involving polar auxin transport (PAT. However, limited information is available about the function of the other AtCRK genes. Here, we report a comparative analysis of the Arabidopsis CRK genes, including transcription regulation, intracellular localization, and biological function. AtCRK transcripts were detectable in all organs tested and a considerable variation in transcript levels was detected among them. Most AtCRK proteins localized at the plasma membrane as revealed by microscopic analysis of 35S::cCRK-GFP (Green Fluorescence Protein expressing plants or protoplasts. Interestingly, 35S::cCRK1-GFP and 35S::cCRK7-GFP had a dual localization pattern which was associated with plasma membrane and endomembrane structures, as well. Analysis of T-DNA insertion mutants revealed that AtCRK genes are important for root growth and control of gravitropic responses in roots and hypocotyls. While Atcrk mutants were indistinguishable from wild type plants in short days, Atcrk1-1 mutant had serious growth defects under continuous illumination. Semi-dwarf phenotype of Atcrk1-1 was accompanied with chlorophyll depletion, disturbed photosynthesis, accumulation of singlet oxygen, and enhanced cell death in photosynthetic tissues. AtCRK1 is therefore important to maintain cellular homeostasis during continuous illumination.

Interaction between gas cooking and GSTM1 null genotype in bronchial responsiveness: results from the European Community Respiratory Health Survey

Science.gov (United States)

Amaral, André F S; Ramasamy, Adaikalavan; Castro-Giner, Francesc; Minelli, Cosetta; Accordini, Simone; Sørheim, Inga-Cecilie; Pin, Isabelle; Kogevinas, Manolis; Jõgi, Rain; Balding, David J; Norbäck, Dan; Verlato, Giuseppe; Olivieri, Mario; Probst-Hensch, Nicole; Janson, Christer; Zock, Jan-Paul; Heinrich, Joachim; Jarvis, Deborah L

2014-01-01

Background Increased bronchial responsiveness is characteristic of asthma. Gas cooking, which is a major indoor source of the highly oxidant nitrogen dioxide, has been associated with respiratory symptoms and reduced lung function. However, little is known about the effect of gas cooking on bronchial responsiveness and on how this relationship may be modified by variants in the genes GSTM1, GSTT1 and GSTP1, which influence antioxidant defences. Methods The study was performed in subjects with forced expiratory volume in one second at least 70% of predicted who took part in the multicentre European Community Respiratory Health Survey, had bronchial responsiveness assessed by methacholine challenge and had been genotyped for GSTM1, GSTT1 and GSTP1-rs1695. Information on the use of gas for cooking was obtained from interviewer-led questionnaires. Effect modification by genotype on the association between the use of gas for cooking and bronchial responsiveness was assessed within each participating country, and estimates combined using meta-analysis. Results Overall, gas cooking, as compared with cooking with electricity, was not associated with bronchial responsiveness (β=−0.08, 95% CI −0.40 to 0.25, p=0.648). However, GSTM1 significantly modified this effect (β for interaction=−0.75, 95% CI −1.16 to −0.33, p=4×10−4), with GSTM1 null subjects showing more responsiveness if they cooked with gas. No effect modification by GSTT1 or GSTP1-rs1695 genotypes was observed. Conclusions Increased bronchial responsiveness was associated with gas cooking among subjects with the GSTM1 null genotype. This may reflect the oxidant effects on the bronchi of exposure to nitrogen dioxide. PMID:24613990

Response of a relativistic quantum magnetized electron gas

International Nuclear Information System (INIS)

Melrose, Donald B; Weise, Jeanette I

2009-01-01

The response 4-tensor is derived for a spin-independent, relativistic magnetized quantum electron gas. The sum over spins is carried out both directly and using a procedure due to Ritus. The 4-tensor components are written in terms of a sum over the two solutions of the resonance condition for the particle 4-momentum. It is shown that the dispersive properties may be described in terms of a single plasma dispersion function, for arbitrary occupation numbers for electrons and positrons in each Landau level. The plasma dispersion function is evaluated explicitly in the completely degenerate and nondegenerate thermal limits. The perpendicular wave number appears in the arguments of J-functions, which are proportional to generalized Laguerre polynomials, but not in the plasma dispersion function. The result generalizes a known form for the response tensor for parallel propagation (in the completely degenerate case), when the J-functions are either zero or unity, to arbitrary angles of propagation.

Response of a thermal barrier system to acoustic excitation in a gas turbine nuclear reactor

International Nuclear Information System (INIS)

Betts, W.S. Jr.; Blevins, R.D.

1980-11-01

A gas turbine located within a High-Temperature Gas-Cooled Reactor (HTGR) induces high acoustic sound pressure levels into the primary coolant (helium). This acoustic loading induces high cycle fatigue stresses which may control the design of the thermal barrier system. This study examines the dynamic response of a thermal barrier configuration consisting of a fibrous insulation compressed against the reactor vessel by a coverplate which is held in position by a central attachment fixture. The results of dynamic vibration analyses indicate the effect of the plate size and curvature and the attachment size on the response of the thermal barrier

Soil gas radon response to environmental and soil physics variables

International Nuclear Information System (INIS)

Thomas, D.M.; Chen, C.; Holford, D.

1991-01-01

During the last three years a field study of soil gas radon activities conducted at Poamoho, Oahu, has shown that the primary environmental variables that control radon transport in shallow tropical soils are synoptic and diurnal barometric pressure changes and soil moisture levels. Barometric pressure changes drive advective transport and mixing of soil gas with atmospheric air; soil moisture appears to control soil porosity and permeability to enhance or inhibit advective and diffusive radon transport. An advective barrier test/control experiment has shown that advective exchange of soil gas and air may account for a substantial proportion of the radon loss from shallow soils but does not significantly affect radon activities at depths greater than 2.3 m. An irrigation test/control experiment also suggests that, at soil moisture levels approaching field capacity, saturation of soil macroporosity can halt all advective transport of radon and limit diffusive mobility to that occurring in the liquid phase. The results of the authors field study have been used to further refine and extend a numerical model, RN3D, that has been developed by Pacific Northwest Laboratories to simulate subsurface transport of radon. The field data have allowed them to accurately simulate the steady state soil gas radon profile at their field site and to track transient radon activities under the influence of barometric pressure changes and in response to changes in soil permeability that result from variations in soil moisture levels. Further work is continuing on the model to enable it to properly account for the relative effects of advective transport of soil gas through cracks and diffusive mobility in the bulk soils

Corporate environmental responsiveness strategies and competitiveness in the North American oil and gas industry

Energy Technology Data Exchange (ETDEWEB)

Sharma, S.

1996-12-31

An exploratory study was conducted in the Canadian oil and gas industries to build a perspective on the environmental responsive strategies employed by the industry. Based on this study and a detailed review of the literature, hypotheses were formulated regarding organizational determinants of environmental responsiveness strategies and the impact of these strategies on firm performance. The hypotheses were tested through a questionnaire-based comparative survey of multiple informants in the Canadian and U.S. oil and gas industries. Results revealed that environmental responsiveness was influenced by management interpretation of environmental issues as threats or opportunities. Other significant factors noted were company size and resources, and collaborative problem-solving relationships with stockholders seen as spokespersons for the natural environment. Managerial interpretations of environmental issues appeared to be affected by leadership styles, organization design factors such as managerial discretion in decisions on the business/ natural environment interface, and the use of environmental performance indicators in employee control systems. refs., figs.

Corporate environmental responsiveness strategies and competitiveness in the North American oil and gas industry

International Nuclear Information System (INIS)

Sharma, S.

1996-01-01

An exploratory study was conducted in the Canadian oil and gas industries to build a perspective on the environmental responsive strategies employed by the industry. Based on this study and a detailed review of the literature, hypotheses were formulated regarding organizational determinants of environmental responsiveness strategies and the impact of these strategies on firm performance. The hypotheses were tested through a questionnaire-based comparative survey of multiple informants in the Canadian and U.S. oil and gas industries. Results revealed that environmental responsiveness was influenced by management interpretation of environmental issues as threats or opportunities. Other significant factors noted were company size and resources, and collaborative problem-solving relationships with stockholders seen as spokespersons for the natural environment. Managerial interpretations of environmental issues appeared to be affected by leadership styles, organization design factors such as managerial discretion in decisions on the business/ natural environment interface, and the use of environmental performance indicators in employee control systems. refs., figs

Effect of Water Vapor and Surface Morphology on the Low Temperature Response of Metal Oxide Semiconductor Gas Sensors

Directory of Open Access Journals (Sweden)

Konrad Maier

2015-09-01

Full Text Available In this work the low temperature response of metal oxide semiconductor gas sensors is analyzed. Important characteristics of this low-temperature response are a pronounced selectivity to acid- and base-forming gases and a large disparity of response and recovery time constants which often leads to an integrator-type of gas response. We show that this kind of sensor performance is related to the trend of semiconductor gas sensors to adsorb water vapor in multi-layer form and that this ability is sensitively influenced by the surface morphology. In particular we show that surface roughness in the nanometer range enhances desorption of water from multi-layer adsorbates, enabling them to respond more swiftly to changes in the ambient humidity. Further experiments reveal that reactive gases, such as NO2 and NH3, which are easily absorbed in the water adsorbate layers, are more easily exchanged across the liquid/air interface when the humidity in the ambient air is high.

Seismic response of high temperature gas-cooled reactor core with block-type fuel, (2)

International Nuclear Information System (INIS)

Ikushima, Takeshi; Honma, Toshiaki.

1980-01-01

For the aseismic design of a high temperature gas-cooled reactor (HTGR) with block-type fuel, it is necessary to predict the motion and force of core columns and blocks. To reveal column vibration characteristics in three-dimensional space and impact response, column vibration tests were carried out with a scale model of a one-region section (seven columns) of the HTGR core. The results are as follows: (1) the column has a soft spring characteristic based on stacked blocks connected with loose pins, (2) the column has whirling phenomena, (3) the compression spring force simulating the gas pressure has the effect of raising the column resonance frequency, and (4) the vibration behavior of the stacked block column and impact response of the surrounding columns show agreement between experiment and analysis. (author)

Ionization and scintillation response of high-pressure xenon gas to alpha particles

International Nuclear Information System (INIS)

Álvarez, V; Cárcel, S; Cervera, A; Díaz, J; Ferrario, P; Gil, A; Gómez-Cadenas, J J; Borges, F I G; Conde, C A N; Fernandes, L M P; Freitas, E D C; Cebrián, S; Dafni, T; Gómez, H; Egorov, M; Gehman, V M; Goldschmidt, A; Esteve, R; Evtoukhovitch, P; Ferreira, A L

2013-01-01

High-pressure xenon gas is an attractive detection medium for a variety of applications in fundamental and applied physics. In this paper we study the ionization and scintillation detection properties of xenon gas at 10 bar pressure. For this purpose, we use a source of alpha particles in the NEXT-DEMO time projection chamber, the large scale prototype of the NEXT-100 neutrinoless double beta decay experiment, in three different drift electric field configurations. We measure the ionization electron drift velocity and longitudinal diffusion, and compare our results to expectations based on available electron scattering cross sections on pure xenon. In addition, two types of measurements addressing the connection between the ionization and scintillation yields are performed. On the one hand we observe, for the first time in xenon gas, large event-by-event correlated fluctuations between the ionization and scintillation signals, similar to that already observed in liquid xenon. On the other hand, we study the field dependence of the average scintillation and ionization yields. Both types of measurements may shed light on the mechanism of electron-ion recombination in xenon gas for highly-ionizing particles. Finally, by comparing the response of alpha particles and electrons in NEXT-DEMO, we find no evidence for quenching of the primary scintillation light produced by alpha particles in the xenon gas.

Multi-gas interaction modeling on decorated semiconductor interfaces: A novel Fermi distribution-based response isotherm and the inverse hard/soft acid/base concept

Energy Technology Data Exchange (ETDEWEB)

Laminack, William [Department of Physics, Georgia Institute of Technology, Atlanta, GA 30332 (United States); Gole, James, E-mail: James.Gole@physics.gatech.edu [Department of Physics, Georgia Institute of Technology, Atlanta, GA 30332 (United States); Department of Mechanical Engineering, Georgia Tech, Atlanta, GA 30332 (United States)

2015-12-30

Graphical abstract: Visual representation of the PS interface interacting with mixed gas configurations. The red dots correspond to nanostructured metal oxides. Each combination of distinct molecules are labeled below the pores, which are oversized in the figure. - Highlights: • First study of mixed gas analytes interacting with a micro-porous silicon substrate. • Responses are represented by a newly developed response absorption isotherm. • This isotherm is modeled on the basis of the Fermi distribution function. • The developing IHSAB concept explains multi-gas analyte–analyte interactions. - Abstract: A unique MEMS/NEMS approach is presented for the modeling of a detection platform for mixed gas interactions. Mixed gas analytes interact with nanostructured decorating metal oxide island sites supported on a microporous silicon substrate. The Inverse Hard/Soft acid/base (IHSAB) concept is used to assess a diversity of conductometric responses for mixed gas interactions as a function of these nanostructured metal oxides. The analyte conductometric responses are well represented using a combination diffusion/absorption-based model for multi-gas interactions where a newly developed response absorption isotherm, based on the Fermi distribution function is applied. A further coupling of this model with the IHSAB concept describes the considerations in modeling of multi-gas mixed analyte–interface, and analyte–analyte interactions. Taking into account the molecular electronic interaction of both the analytes with each other and an extrinsic semiconductor interface we demonstrate how the presence of one gas can enhance or diminish the reversible interaction of a second gas with the extrinsic semiconductor interface. These concepts demonstrate important considerations in the array-based formats for multi-gas sensing and its applications.

Correlations between gravitropic curvature and auxin movement across gravistimulated roots of Zea mays

Science.gov (United States)

Young, L. M.; Evans, M. L.; Hertel, R.

1990-01-01

We compared the kinetics of auxin redistribution across the caps of primary roots of 2-day-old maize (Zea mays, cv Merit) seedlings with the time course of gravitropic curvature. [3H] indoleacetic acid was applied to one side of the cap in an agar donor and radioactivity moving across the cap was collected in an agar receiver applied to the opposite side. Upon gravistimulation the roots first curved upward slightly, then returned to the horizontal and began curving downward, reaching a final angle of about 67 degrees. Movement of label across the caps of gravistimulated roots was asymmetric with preferential downward movement (ratio downward/upward = ca. 1.6, radioactivity collected during the 90 min following beginning of gravistimulation). There was a close correlation between the development of asymmetric auxin movement across the root cap and the rate of curvature, with both values increasing to a maximum and then declining as the roots approached the final angle of curvature. In roots preadapted to gravity (alternate brief stimulation on opposite flanks over a period of 1 hour) the initial phase of upward curvature was eliminated and downward bending began earlier than for controls. The correlation between asymmetric auxin movement and the kinetics of curvature also held in comparisons between control and preadapted roots. Both downward auxin transport asymmetry and downward curvature occurred earlier in preadapted roots than in controls. These findings are consistent with suggestions that the root cap is not only the site of perception but also the location of the initial redistribution of effectors that ultimately leads to curvature.

Pharmacological analysis of calcium transients in response to gravity vector change in Arabidopsis hypocotyls and petioles.

Science.gov (United States)

Toyota, M.; Furuichi, T.; Tatsumi, H.; Sokabe, M.

Plants regulate their growth and morphology in response to gravity field known as gravitropism in general In the process of gravitropism gravity sensing will form the critical earliest event which is supposed to take place in specialized cells statocytes such as columella cells and shoot endodermal cells Although gravistimulation is assumed to be converted into certain intracellular signals the underlying transduction mechanisms have hardly been explored One of the potential candidates for the intracellular signals is an increase in the cytoplasmic free calcium concentration Ca 2 c Here we measured Ca 2 c changes induced by gravistimulation in seedlings of Arabidopsis thaliana expressing aequorin as a calcium reporter When a plate of seedlings was turned through 180 r Ca 2 c transiently increased within 50 s and decayed exponentially with a time constant of ca 60 s The amplitude of the Ca 2 c increase was independent of the angular velocity of the rotation The Ca 2 c increase was reversibly blocked by extracellularly applied potential mechanosensitive channel blockers La 3 Gd 3 or a Ca 2 chelator BAPTA indicating that it arose from Ca 2 -influx via Ca 2 -permeable channel s on the plasma membrane Furthermore the Ca 2 c increase was attenuated by actin-disrupting drugs latrunculin B cytochalasin B but not by microtuble-disrupting drugs oryzalin nocodazole indicating that the activation of

The sensitivity and dynamic response of field ionization gas sensor based on ZnO nanorods

International Nuclear Information System (INIS)

Min Jiahua; Liang Xiaoyan; Wang Bin; Wang Linjun; Zhao Yue; Shi Weimin; Xia Yiben

2011-01-01

Field ionization gas sensors based on ZnO nanorods (50–300 nm in diameter, and 3–8 μm in length) with and without a buffer layer were fabricated, and the influence of the orientation of nano-ZnO on the ionization response of devices was discussed, including the sensitivity and dynamic response of the ZnO nanorods with preferential orientation. The results indicated that ZnO nanorods as sensor anode could dramatically decrease the breakdown voltage. The XRD and SEM images illustrated that nano-ZnO with a ZnO buffer layer displayed high c-axis orientation, which helps to significantly reduce the breakdown voltage. Device A based on ZnO nanorods with a ZnO buffer layer could distinguish toluene and acetone. The dynamic responses of device A to the NO x compounds presented the sensitivity of 0.045 ± 0.007 ppm/pA and the response speed within 17–40 s, and indicated a linear relationship between NO x concentration and current response at low NO x concentrations. In addition, the dynamic responses to benzene, isopropyl alcohol, ethanol, and methanol reveals that the device has higher sensitivity to gas with larger static polarizability and lower ionization energy.

Study on time response character for high pressure gas ionization chamber of krypton and xenon

International Nuclear Information System (INIS)

Tan Chunming; Wu Haifeng; Qing Shangyu; Wang Liqiang

2006-01-01

The time response character for Kr and Xe high pressure gas ionization chamber is analyzed and deduced. Compared with the measure data of pulse rising time for three gas-filled ionization chambers, the calculated and experimental results are equal to each other. The rising time less than 10 ms for this kind of ionization chamber can be achieved, so this ionization chamber is able to meet the requirement for imaging detection. (authors)

A meta-analysis of leaf gas exchange and water status responses to drought.

Science.gov (United States)

Yan, Weiming; Zhong, Yangquanwei; Shangguan, Zhouping

2016-02-12

Drought is considered to be one of the most devastating natural hazards, and it is predicted to become increasingly frequent and severe in the future. Understanding the plant gas exchange and water status response to drought is very important with regard to future climate change. We conducted a meta-analysis based on studies of plants worldwide and aimed to determine the changes in gas exchange and water status under different drought intensities (mild, moderate and severe), different photosynthetic pathways (C3 and C4) and growth forms (herbs, shrubs, trees and lianas). Our results were as follows: 1) drought negatively impacted gas exchange and water status, and stomatal conductance (gs) decreased more than other physiological traits and declined to the greatest extent in shrubs and C3 plants. Furthermore, C4 plants had an advantage compared to C3 plants under the same drought conditions. 2) The decrease in gs mainly reduced the transpiration rate (Tr), and gs could explain 55% of the decrease in the photosynthesis (A) and 74% of the decline in Tr. 3). Finally, gas exchange showed a close relationship with the leaf water status. Our study provides comprehensive information about the changes in plant gas exchange and water status under drought.

Multi-gas interaction modeling on decorated semiconductor interfaces: A novel Fermi distribution-based response isotherm and the inverse hard/soft acid/base concept

Science.gov (United States)

Laminack, William; Gole, James

2015-12-01

A unique MEMS/NEMS approach is presented for the modeling of a detection platform for mixed gas interactions. Mixed gas analytes interact with nanostructured decorating metal oxide island sites supported on a microporous silicon substrate. The Inverse Hard/Soft acid/base (IHSAB) concept is used to assess a diversity of conductometric responses for mixed gas interactions as a function of these nanostructured metal oxides. The analyte conductometric responses are well represented using a combination diffusion/absorption-based model for multi-gas interactions where a newly developed response absorption isotherm, based on the Fermi distribution function is applied. A further coupling of this model with the IHSAB concept describes the considerations in modeling of multi-gas mixed analyte-interface, and analyte-analyte interactions. Taking into account the molecular electronic interaction of both the analytes with each other and an extrinsic semiconductor interface we demonstrate how the presence of one gas can enhance or diminish the reversible interaction of a second gas with the extrinsic semiconductor interface. These concepts demonstrate important considerations in the array-based formats for multi-gas sensing and its applications.

The ARG1-LIKE2 gene of Arabidopsis functions in a gravity signal transduction pathway that is genetically distinct from the PGM pathway

Science.gov (United States)

Guan, Changhui; Rosen, Elizabeth S.; Boonsirichai, Kanokporn; Poff, Kenneth L.; Masson, Patrick H.

2003-01-01

The arl2 mutants of Arabidopsis display altered root and hypocotyl gravitropism, whereas their inflorescence stems are fully gravitropic. Interestingly, mutant roots respond like the wild type to phytohormones and an inhibitor of polar auxin transport. Also, their cap columella cells accumulate starch similarly to wild-type cells, and mutant hypocotyls display strong phototropic responses to lateral light stimulation. The ARL2 gene encodes a DnaJ-like protein similar to ARG1, another protein previously implicated in gravity signal transduction in Arabidopsis seedlings. ARL2 is expressed at low levels in all organs of seedlings and plants. arl2-1 arg1-2 double mutant roots display kinetics of gravitropism similar to those of single mutants. However, double mutants carrying both arl2-1 and pgm-1 (a mutation in the starch-biosynthetic gene PHOSPHOGLUCOMUTASE) at the homozygous state display a more pronounced root gravitropic defect than the single mutants. On the other hand, seedlings with a null mutation in ARL1, a paralog of ARG1 and ARL2, behave similarly to the wild type in gravitropism and other related assays. Taken together, the results suggest that ARG1 and ARL2 function in the same gravity signal transduction pathway in the hypocotyl and root of Arabidopsis seedlings, distinct from the pathway involving PGM.

Adaptation response of Arabidopsis thaliana to random positioning

Science.gov (United States)

Kittang, A.-I.; Winge, P.; van Loon, J. J. W. A.; Bones, A. M.; Iversen, T.-H.

2013-10-01

Arabidopsis thaliana seedlings were exposed on a Random Positioning Machine (RPM) under light conditions for 16 h and the samples were analysed using microarray techniques as part of a preparation for a space experiment on the International Space Station (ISS). The results demonstrated a moderate to low regulation of 55 genes (genes). Genes encoding proteins associated with the chaperone system (e.g. heat shock proteins, HSPs) and enzymes in the flavonoid biosynthesis were induced. Most of the repressed genes were associated with light and sugar responses. Significant up-regulation of selected HSP genes was found by quantitative Real-Time PCR in 1 week old plants after the RPM exposure both in light and darkness. Higher quantity of DPBA (diphenylboric acid 2-amino-ethyl ester) staining was observed in the whole root and in the root elongation zone of the seedlings exposed on the RPM by use of fluorescent microscopy, indicating higher flavonoid content. The regulated genes and an increase of flavonoids are related to several stresses, but increased occurrence of HSPs and flavonoids are also representative for normal growth (e.g. gravitropism). The response could be a direct stress response or an integrated response of the two signal pathways of light and gravity resulting in an overall light response.

Lazy gene (la) responsible for both an agravitropism of seedlings and lazy habit of tiller growth in rice (Oryza sativa L.).

Science.gov (United States)

Abe, K; Takahashi, H; Suge, H

1996-12-01

Using an isogenic line of rice having lazy gene (la), we studied the correlation between the agravitropic response at the young seedling stage and the lazy habit (prostrate growth of tillers) at the more advanced stage of growth. In this study, it was found that both agravitropism and lazy habit were controlled by the single recessive la gene. That is, F2 segregants of Kamenoo x lazy-Kamenoo, which had an agravitropic response at their young seedling stage, showed a lazy habit of growth in the more advanced stage of vegetative growth. On the other hand, seedlings that showed normal gravitropic curvature at their early stage of growth had an upright growth in the mature stage.

Gas Composition Sensor for Natural Gas and Biogas

NARCIS (Netherlands)

Boersma, A.; Sweelsen, J.; Blokland, H.

2016-01-01

The calorific value of energetic gasses is an important parameter in the quality assessment of gas steams, and can be calculated from the chemical composition of the gas. An array of capacitive sensor electrodes was developed, each functionalized with a gas responsive coating to measure the

Protein synthesis in geostimulated root caps

Science.gov (United States)

Feldman, L. J.

1982-01-01

A study is presented of the processes occurring in the root cap of corn which are requisite for the formation of root cap inhibitor and which can be triggered or modulated by both light and gravity. The results of this study indicate the importance of protein synthesis for light-induced gravitropic bending in roots. Root caps in which protein synthesis is prevented are unable to induce downward bending. This suggests that light acts by stimulating proteins which are necessary for the translation of the gravitropic stimulus into a growth response (downward bending). The turnover of protein with time was also examined in order to determine whether light acts by stimulating the synthesis of unique proteins required for downward growth. It is found that auxin in combination with light allows for the translation of the gravitropic stimulus into a growth response at least in part through the modification of protein synthesis. It is concluded that unique proteins are stimulated by light and are involved in promoting the downward growth in roots which are responding to gravity.

The dew point response of the annulus gas system of Bruce NGS A

International Nuclear Information System (INIS)

Kenchington, J.; Ellis, P.J.; Meranda, D.

1983-01-01

The dew point response of the Annulus Gas System in Bruce A, Units 1 and 2 has been modelled in order to alert the operator of the presence of heavy water and to estimate the leak rate into the annulus. The computer model can be easily adapted to determine the Annulus Gas System dew point response in any station. It models the complex arrangement of the system and the transportation of moisture through the annuli by a combination of plug flow and mixing of CO 2 and D 2 O vapor. It predicts the response of the dew point monitor for a range of specified leak rates and positions of a leaking channel in a string of channels. This model has been used to calculate the variation of dew point and rate of change of dew point with respect to time (t). It shows that there is a maximum in the rate of dew point change (dT/dt) with respect to the corresponding dew point (T). This maximum is unique for a given leak rate and channel position. It is independent of the starting time for the leak. The computer programme has been verified by an analytical solution for the model

Enhancement of gas sensor response of nanocrystalline zinc oxide for ammonia by plasma treatment

International Nuclear Information System (INIS)

Hou, Yue; Jayatissa, Ahalapitiya H.

2014-01-01

The effect of oxygen plasma treatment on nanocrystalline ZnO thin film based gas sensor was investigated. ZnO thin films were synthesized on alkali-free glass substrates by a sol–gel process. ZnO thin films were treated with oxygen plasma to change the number of vacancies/defects in ZnO. The effect of oxygen plasma on the structural, electrical, optical and gas sensing properties was investigated as a function of plasma treatment time. The results suggest that the microstructure and the surface morphology can be tuned by oxygen plasma treatment. The optical transmission in the visible range varies after the oxygen plasma treatment. Moreover, it is found that the oxygen plasma has significant impact on the electrical properties of ZnO thin films indicating a variation of resistivity. The oxygen plasma treated ZnO thin film exhibits an enhanced sensing response towards NH 3 in comparison with that of the as-deposited ZnO sensor. When compared with the as-deposited ZnO film, the sensing response was improved by 50% for the optimum oxygen plasma treatment time of 8 min. The selectivity of 8 min plasma treated ZnO sensor was also examined for an important industrial gas mixture of H 2 , CH 4 and NH 3 .

Response of a reactor building due to detonation of flat layered gas clouds

International Nuclear Information System (INIS)

Frik, G.

1984-05-01

The stress of the containment of a PWR plant of today is calculated for the loading of three detonating flat layered gas clouds. The dynamic response of the structure due to the blast wave is determined and comparisons are made with previous results of the detonating stochiometric gas cloud and with results of the individual task 11A (GRS). The calculations were realized with the method of modal superposition and linear elastic material laws. The stress conditions of the structure were comprehended by three loading cases of the flat, layered gas clouds. The first loading case B(a) leads to high stresses, which are not interpretable with a linear analysis. On the other hand, the loading case B(b) leads to stresses which are not much above and B(c) to stresses which are not much below the yield stress. It is demonstrated for a linear analysis, that the structure will not be injured by the detonation wave of case B(c). (orig./HP) [de

Hydrothermal synthesis of p-type nanocrystalline NiO nanoplates for high response and low concentration hydrogen gas sensor application

KAUST Repository

Nakate, Umesh T.; Lee, Gun Hee; Ahmad, Rafiq; Patil, Pramila; Bhopate, Dhanaji P.; Hahn, Y.B.; Yu, Y.T.; Suh, Eun-kyung

2018-01-01

High quality nanocrystalline NiO nanoplates were synthesized using surfactant and template free hydrothermal route. The gas sensing properties of NiO nanoplates were investigated. The nanoplates morphology of NiO with average thickness ~20 nm and diameter ~100 nm has been confirmed by FE-SEM and TEM. Crystalline quality of NiO has been studied using HRTEM and SAED techniques. Structural properties and elemental compositions have been analysed by XRD and energy dispersive spectrometer (EDS) respectively. The detailed investigation of structural parameters has been carried out. The optical properties of NiO were analyzed from UV-Visible and photoluminescence spectra. NiO nanoplates have good selectivity towards hydrogen (H2) gas. The lowest H2 response of 3% was observed at 2 ppm, whereas 90% response was noted for 100 ppm at optimized temperature of 200 °C with response time 180 s. The H2 responses as functions of different operating temperature as well as gas concentrations have been studied along with sensor stability. The hydrogen sensing mechanism was also elucidated.

Hydrothermal synthesis of p-type nanocrystalline NiO nanoplates for high response and low concentration hydrogen gas sensor application

KAUST Repository

Nakate, Umesh T.

2018-05-30

High quality nanocrystalline NiO nanoplates were synthesized using surfactant and template free hydrothermal route. The gas sensing properties of NiO nanoplates were investigated. The nanoplates morphology of NiO with average thickness ~20 nm and diameter ~100 nm has been confirmed by FE-SEM and TEM. Crystalline quality of NiO has been studied using HRTEM and SAED techniques. Structural properties and elemental compositions have been analysed by XRD and energy dispersive spectrometer (EDS) respectively. The detailed investigation of structural parameters has been carried out. The optical properties of NiO were analyzed from UV-Visible and photoluminescence spectra. NiO nanoplates have good selectivity towards hydrogen (H2) gas. The lowest H2 response of 3% was observed at 2 ppm, whereas 90% response was noted for 100 ppm at optimized temperature of 200 °C with response time 180 s. The H2 responses as functions of different operating temperature as well as gas concentrations have been studied along with sensor stability. The hydrogen sensing mechanism was also elucidated.

Gas response properties of citrate gel synthesized nanocrystalline MgFe2O4: Effect of sintering temperature

International Nuclear Information System (INIS)

Patil, J.Y.; Mulla, I.S.; Suryavanshi, S.S.

2013-01-01

Graphical abstract: Display Omitted Highlights: ► Synthesis of nanocrystalline MgFe 2 O 4 by economical citrate gel combustion method. ► Structural, morphological, and gas response properties of MgFe 2 O 4 . ► Enhancement in selectivity of MgFe 2 O 4 towards LPG with sintering temperature. ► Use of MgFe 2 O 4 to detect different gases at different operating temperatures. -- Abstract: Spinel type MgFe 2 O 4 material was synthesized by citrate gel combustion method. The effect of sintering temperature on structural, morphological, and gas response properties was studied. The powder X-ray diffraction pattern and transmission electron microscope study confirms nanocrystalline spinel structure of the synthesized powder. The material was tested for response properties to various reducing gases like liquid petroleum gas (LPG), acetone, ethanol, and ammonia. The results demonstrated n-type semiconducting behavior of MgFe 2 O 4 material. It was revealed that MgFe 2 O 4 sintered at 973 K was most sensitive to LPG at 648 K and to acetone at 498 K. However MgFe 2 O 4 sintered at 1173 K exhibited higher response and selectivity to LPG with marginal increase in the operating temperature. Furthermore, the sensor exhibited a fast response and a good recovery. It was observed that the particles size, porosity, and surface activity of the sensor material is affected by the sintering temperature.

Isolation of a novel mutant gene for soil-surface rooting in rice (Oryza sativa L.).

Science.gov (United States)

Hanzawa, Eiko; Sasaki, Kazuhiro; Nagai, Shinsei; Obara, Mitsuhiro; Fukuta, Yoshimichi; Uga, Yusaku; Miyao, Akio; Hirochika, Hirohiko; Higashitani, Atsushi; Maekawa, Masahiko; Sato, Tadashi

2013-11-20

Root system architecture is an important trait affecting the uptake of nutrients and water by crops. Shallower root systems preferentially take up nutrients from the topsoil and help avoid unfavorable environments in deeper soil layers. We have found a soil-surface rooting mutant from an M2 population that was regenerated from seed calli of a japonica rice cultivar, Nipponbare. In this study, we examined the genetic and physiological characteristics of this mutant. The primary roots of the mutant showed no gravitropic response from the seedling stage on, whereas the gravitropic response of the shoots was normal. Segregation analyses by using an F2 population derived from a cross between the soil-surface rooting mutant and wild-type Nipponbare indicated that the trait was controlled by a single recessive gene, designated as sor1. Fine mapping by using an F2 population derived from a cross between the mutant and an indica rice cultivar, Kasalath, revealed that sor1 was located within a 136-kb region between the simple sequence repeat markers RM16254 and 2935-6 on the terminal region of the short arm of chromosome 4, where 13 putative open reading frames (ORFs) were found. We sequenced these ORFs and detected a 33-bp deletion in one of them, Os04g0101800. Transgenic plants of the mutant transformed with the genomic fragment carrying the Os04g0101800 sequence from Nipponbare showed normal gravitropic responses and no soil-surface rooting. These results suggest that sor1, a rice mutant causing soil-surface rooting and altered root gravitropic response, is allelic to Os04g0101800, and that a 33-bp deletion in the coding region of this gene causes the mutant phenotypes.

Coupled multiphase flow and closure analysis of repository response to waste-generated gas at the Waste Isolation Pilot Plant (WIPP)

Energy Technology Data Exchange (ETDEWEB)

Freeze, G.A.; Larson, K.W. [INTERA Inc., Austin, TX (United States); Davies, P.B. [Sandia National Laboratories, Albuquerque, NM (United States)

1995-10-01

A long-term assessment of the Waste Isolation Pilot Plant (WIPP) repository performance must consider the impact of gas generation resulting from the corrosion and microbial degradation of the emplaced waste. A multiphase fluid flow code, TOUGH2/EOS8, was adapted to model the processes of gas generation, disposal room creep closure, and multiphase (brine and gas) fluid flow, as well as the coupling between the three processes. System response to gas generation was simulated with a single, isolated disposal room surrounded by homogeneous halite containing two anhydrite interbeds, one above and one below the room. The interbeds were assumed to have flow connections to the room through high-permeability, excavation-induced fractures. System behavior was evaluated by tracking four performance measures: (1) peak room pressure; (2) maximum brine volume in the room; (3) total mass of gas expelled from the room; and (4) the maximum gas migration distance in an interbed. Baseline simulations used current best estimates of system parameters, selected through an evaluation of available data, to predict system response to gas generation under best-estimate conditions. Sensitivity simulations quantified the effects of parameter uncertainty by evaluating the change in the performance measures in response to parameter variations. In the sensitivity simulations, a single parameter value was varied to its minimum and maximum values, representative of the extreme expected values, with all other parameters held at best-estimate values. Sensitivity simulations identified the following parameters as important to gas expulsion and migration away from a disposal room: interbed porosity; interbed permeability; gas-generation potential; halite permeability; and interbed threshold pressure. Simulations also showed that the inclusion of interbed fracturing and a disturbed rock zone had a significant impact on system performance.

Coupled multiphase flow and closure analysis of repository response to waste-generated gas at the Waste Isolation Pilot Plant (WIPP)

International Nuclear Information System (INIS)

Freeze, G.A.; Larson, K.W.; Davies, P.B.

1995-10-01

A long-term assessment of the Waste Isolation Pilot Plant (WIPP) repository performance must consider the impact of gas generation resulting from the corrosion and microbial degradation of the emplaced waste. A multiphase fluid flow code, TOUGH2/EOS8, was adapted to model the processes of gas generation, disposal room creep closure, and multiphase (brine and gas) fluid flow, as well as the coupling between the three processes. System response to gas generation was simulated with a single, isolated disposal room surrounded by homogeneous halite containing two anhydrite interbeds, one above and one below the room. The interbeds were assumed to have flow connections to the room through high-permeability, excavation-induced fractures. System behavior was evaluated by tracking four performance measures: (1) peak room pressure; (2) maximum brine volume in the room; (3) total mass of gas expelled from the room; and (4) the maximum gas migration distance in an interbed. Baseline simulations used current best estimates of system parameters, selected through an evaluation of available data, to predict system response to gas generation under best-estimate conditions. Sensitivity simulations quantified the effects of parameter uncertainty by evaluating the change in the performance measures in response to parameter variations. In the sensitivity simulations, a single parameter value was varied to its minimum and maximum values, representative of the extreme expected values, with all other parameters held at best-estimate values. Sensitivity simulations identified the following parameters as important to gas expulsion and migration away from a disposal room: interbed porosity; interbed permeability; gas-generation potential; halite permeability; and interbed threshold pressure. Simulations also showed that the inclusion of interbed fracturing and a disturbed rock zone had a significant impact on system performance

Regional Ventilation Changes in the Lung: Treatment Response Mapping by Using Hyperpolarized Gas MR Imaging as a Quantitative Biomarker.

Science.gov (United States)

Horn, Felix C; Marshall, Helen; Collier, Guilhem J; Kay, Richard; Siddiqui, Salman; Brightling, Christopher E; Parra-Robles, Juan; Wild, Jim M

2017-09-01

Purpose To assess the magnitude of regional response to respiratory therapeutic agents in the lungs by using treatment response mapping (TRM) with hyperpolarized gas magnetic resonance (MR) imaging. TRM was used to quantify regional physiologic response in adults with asthma who underwent a bronchodilator challenge. Materials and Methods This study was approved by the national research ethics committee and was performed with informed consent. Imaging was performed in 20 adult patients with asthma by using hyperpolarized helium 3 ( 3 He) ventilation MR imaging. Two sets of baseline images were acquired before inhalation of a bronchodilating agent (salbutamol 400 μg), and one set was acquired after. All images were registered for voxelwise comparison. Regional treatment response, ΔR(r), was calculated as the difference in regional gas distribution (R[r] = ratio of inhaled gas to total volume of a voxel when normalized for lung inflation volume) before and after intervention. A voxelwise activation threshold from the variability of the baseline images was applied to ΔR(r) maps. The summed global treatment response map (ΔR net ) was then used as a global lung index for comparison with metrics of bronchodilator response measured by using spirometry and the global imaging metric percentage ventilated volume (%VV). Results ΔR net showed significant correlation (P treatment effect was detected with all metrics; however, ΔR net showed a lower intersubject coefficient of variation (64%) than all of the other tests (coefficient of variation, ≥99%). Conclusion TRM provides regional quantitative information on changes in inhaled gas ventilation in response to therapy. This method could be used as a sensitive regional outcome metric for novel respiratory interventions. © RSNA, 2017 Online supplemental material is available for this article.

A NRESPG Monte Carlo code for the calculation of neutron response functions for gas counters

Energy Technology Data Exchange (ETDEWEB)

Kudo, K; Takeda, N; Fukuda, A [Electrotechnical Lab., Tsukuba, Ibaraki (Japan); Torii, T; Hashimoto, M; Sugita, T; Yang, X; Dietze, G

1996-07-01

In this paper, we show the outline of the NRESPG and some typical results of the response functions and efficiencies of several kinds of gas counters. The cross section data for the several kinds of filled gases and the wall material of stainless steel or aluminum are taken mainly from ENDF/B-IV. The ENDF/B-V for stainless steel is also used to investigate the influence on pulse height spectra of gas counters due to the difference of nuclear data files. (J.P.N.)

Sumoylation Promotes the Stability of the DNA Sensor cGAS and the Adaptor STING to Regulate the Kinetics of Response to DNA Virus.

Science.gov (United States)

Hu, Ming-Ming; Yang, Qing; Xie, Xue-Qin; Liao, Chen-Yang; Lin, Heng; Liu, Tian-Tian; Yin, Lei; Shu, Hong-Bing

2016-09-20

During viral infection, sensing of cytosolic DNA by the cyclic GMP-AMP synthase (cGAS) activates the adaptor protein STING and triggers an antiviral response. Little is known about the mechanisms that determine the kinetics of activation and deactivation of the cGAS-STING pathway, ensuring effective but controlled innate antiviral responses. Here we found that the ubiquitin ligase Trim38 targets cGas for sumoylation in uninfected cells and during the early phase of viral infection. Sumoylation of cGas prevented its polyubiquitination and degradation. Trim38 also sumoylated Sting during the early phase of viral infection, promoting both Sting activation and protein stability. In the late phase of infection, cGas and Sting were desumoylated by Senp2 and subsequently degraded via proteasomal and chaperone-mediated autophagy pathways, respectively. Our findings reveal an essential role for Trim38 in the innate immune response to DNA virus and provide insight into the mechanisms that ensure optimal activation and deactivation of the cGAS-STING pathway. Copyright © 2016 Elsevier Inc. All rights reserved.

Stimuli-Responsive NO Release for On-Demand Gas-Sensitized Synergistic Cancer Therapy.

Science.gov (United States)

Fan, Wenpei; Yung, Bryant C; Chen, Xiaoyuan

2018-03-08

Featuring high biocompatibility, the emerging field of gas therapy has attracted extensive attention in the medical and scientific communities. Currently, considerable research has focused on the gasotransmitter nitric oxide (NO) owing to its unparalleled dual roles in directly killing cancer cells at high concentrations and cooperatively sensitizing cancer cells to other treatments for synergistic therapy. Of particular note, recent state-of-the-art studies have turned our attention to the chemical design of various endogenous/exogenous stimuli-responsive NO-releasing nanomedicines and their biomedical applications for on-demand NO-sensitized synergistic cancer therapy, which are discussed in this Minireview. Moreover, the potential challenges regarding NO gas therapy are also described, aiming to advance the development of NO nanomedicines as well as usher in new frontiers in this fertile research area. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Hydrodynamic theory for quantum plasmonics: Linear-response dynamics of the inhomogeneous electron gas

DEFF Research Database (Denmark)

Yan, Wei

2015-01-01

We investigate the hydrodynamic theory of metals, offering systematic studies of the linear-response dynamics for an inhomogeneous electron gas. We include the quantum functional terms of the Thomas-Fermi kinetic energy, the von Weizsa¨cker kinetic energy, and the exchange-correlation Coulomb...... energies under the local density approximation. The advantages, limitations, and possible improvements of the hydrodynamic theory are transparently demonstrated. The roles of various parameters in the theory are identified. We anticipate that the hydrodynamic theory can be applied to investigate the linear...... response of complex metallic nanostructures, including quantum effects, by adjusting theory parameters appropriately....

Geologic and porous media factors affecting the 2007 production response characteristics of the JOGMEC/NRCan/AURORA Mallik gas hydrate production research well

Energy Technology Data Exchange (ETDEWEB)

Dallimore, S. R.; Wright, J. F.; Nixon, F. M. [Natural Resources Canada, Sidney, BC (Canada). Geological Survey of Canada; Kurihara, M. [Japan Oil Engineering, Tokyo (Japan); Yamamoto, K.; Fujii, T.; Fujii, K.; Numasawa, M.; Yasuda, M. [Japan Oil, Gas, Metals National Corp., Chiba (Japan). Technical Research Centre; Imasato, Y. [Schlumberger K.K., Fuchinombe (Japan)

2008-07-01

The joint research project between Japan Oil, Gas and Metals National Corporation (JOGMEC), Natural Resources Canada (NRCan) and the Aurora Research Institute was conducted in an effort to measure and monitor the response of a terrestrial gas hydrate reservoir to pressure draw down. This paper reviewed the geologic setting and porous media conditions of a concentrated gas hydrate production interval between 1093 and 1105 m. The short-duration production test was conducted at the Mallik site in Canada's Mackenzie Delta in April 2007. The production interval consists of a sand-dominated succession with occasional silty sand interbeds. Gas hydrate occurs primarily within the sediment pore spaces, with concentrations ranging between 50-90 per cent. Experiments on pore water salinity and porous media conditions on pressure-temperature stability suggest that the partition between gas hydrate stability and instability should be considered as a phase boundary zone rather than a discrete threshold. The experiment revealed that there are significant changes to the physical properties following gas hydrate dissociation, with sediments containing no hydrate behaving as unconsolidated sands. A strong reservoir response to pressure draw down was observed with increasing gas flow during the testing period. Sand inflow to the well during the test may be attributed to loss of sediment strength during gas hydrate dissociation, with the sediment behaving as a gasified slurry. It was concluded that the gas flow response observed during the 2007 production test at Mallik was highly influenced by porous media properties and by the geological heterogeneities which may initiate high permeability conduits in sediments within the production interval of the Mallik gas hydrate reservoir. 18 refs., 6 figs.

A Monte Carlo simulation of the microdosimetric response for thick gas electron multiplier

International Nuclear Information System (INIS)

Hanu, A.; Byun, S.H.; Prestwich, W.V.

2010-01-01

The neutron microdosimetric responses of the thick gas electron multiplier (THGEM) detector were simulated. The THGEM is a promising device for microdosimetry, particularly for measuring the dose spectra of intense radiation fields and for collecting two-dimensional microdosimetric distributions. To investigate the response of the prototype THGEM microdosimetric detector, a simulation was developed using the Geant4 Monte Carlo code. The simulation calculates the deposited energy in the detector sensitive volume for an incident neutron beam. Both neutron energy and angular responses were computed for various neutron beam conditions. The energy response was compared with the reported experimental microdosimetric spectra as well as the evaluated fluence-to-kerma conversion coefficients. The effects of using non-tissue equivalent materials were also investigated by comparing the THGEM detector response with the response of an ideal detector in identical neutron field conditions. The result of the angular response simulations revealed severe angular dependencies for neutron energies above 100 keV. The simulation of a modified detector design gave an angular response pattern close to the ideal case, showing a fluctuation of less than 10% over the entire angular range.

Interaction between gas cooking and GSTM1 null genotype in bronchial responsiveness: results from the European Community Respiratory Health Survey.

NARCIS (Netherlands)

Amaral, A.F.S.; Ramasamy, A.; Castro-Giner, F.; Minelli, C.; Accordini, S.; Sorheim, I.C.; Pin, I.; Kogevinas, M.; Jögi, R.; Balding, D.J.; Norbäck, D.; Verlato, G.; Olivieri, M.; Probst-Hensch, N.; Janson, C.; Zock, J.P.; Heinrich, J.; Jarvis, D.L.

2014-01-01

Background: Increased bronchial responsiveness is characteristic of asthma. Gas cooking, which is a major indoor source of the highly oxidant nitrogen dioxide, has been associated with respiratory symptoms and reduced lung function. However, little is known about the effect of gas cooking on

Fast response of carbon monoxide gas sensors using a highly porous network of ZnO nanoparticles decorated on 3D reduced graphene oxide

Science.gov (United States)

Ha, Nguyen Hai; Thinh, Dao Duc; Huong, Nguyen Thanh; Phuong, Nguyen Huy; Thach, Phan Duy; Hong, Hoang Si

2018-03-01

Zinc oxide (ZnO) nanoparticles loaded onto 3D reduced graphene oxide (3D-RGO) for carbon monoxide (CO) sensing were synthesized using hydrothermal method. The highly porous ZnO/3D-RGO configuration was stable without collapsing and was deposited on the micro-heater of the CO gas sensor. The resulting CO gas sensor displayed high sensitivity, fast response/recovery, and good linearity. The sensor achieved a response value of 85.2% for 1000 ppm CO at a working temperature of 200 °C. The response and recovery times of the sensor were 7 and 9 s for 1000 ppm CO at 200 °C. Similarly, the response value, response time, and recovery time of the sensor at room temperature were 27.5%, 14 s, and 15 s, respectively. The sensor demonstrated a distinct response to various CO concentrations in the range of 1-1000 ppm and good selectivity toward CO gas. In addition, the sensor exhibited good repeatability in multi-cycle and long-term stability.

Fast response of sprayed vanadium pentoxide (V{sub 2}O{sub 5}) nanorods towards nitrogen dioxide (NO{sub 2}) gas detection

Energy Technology Data Exchange (ETDEWEB)

Mane, A.A. [Thin Film Nanomaterials Laboratory, Department of Physics, Shivaji University, Kolhapur 416 004 (India); General Science and Humanities Department, Sant Gajanan Maharaj College of Engineering, Mahagaon, 416 503 (India); Suryawanshi, M.P. [Optoelectronics Convergence Research Center, Department of Materials Science and Engineering, Chonnam National University, 300, Yongbong-Dong, Buk-Gu, Gwangju 500-757 (Korea, Republic of); Kim, J.H., E-mail: jinhyeok@chonnam.ac.kr [Optoelectronics Convergence Research Center, Department of Materials Science and Engineering, Chonnam National University, 300, Yongbong-Dong, Buk-Gu, Gwangju 500-757 (Korea, Republic of); Moholkar, A.V., E-mail: avmoholkar@gmail.com [Thin Film Nanomaterials Laboratory, Department of Physics, Shivaji University, Kolhapur 416 004 (India)

2017-05-01

Highlights: • Effect of solution concentration on physicochemical properties of sprayed V{sub 2}O{sub 5} nanorods is studied. • Good response and short response-recovery times of V{sub 2}O{sub 5} nanorods towards NO{sub 2} gas show it is potential material for fabrication of NO{sub 2} sensor. • The chemisorption mechanism of NO{sub 2} gas on the V{sub 2}O{sub 5} nanorods is discussed. - Abstract: The V{sub 2}O{sub 5} nanorods have been successfully spray deposited at optimized substrate temperature of 400 °C onto the glass substrates using vanadium trichloride (VCl{sub 3}) solution of different concentrations. The effect of solution concentration on the physicochemical and NO{sub 2} gas sensing properties of sprayed V{sub 2}O{sub 5} nanorods is studied at different operating temperatures and gas concentrations. The XRD study reveals the formation of V{sub 2}O{sub 5} having an orthorhombic symmetry. The FE-SEM micrographs show the nanorods-like morphology of V{sub 2}O{sub 5}. The AFM micrographs exhibit a well covered granular surface topography. For direct allowed transition, the band gap energy values are found to be decreased from 2.45 eV to 2.42 eV. The nanorods deposited with 30 mM solution concentration shows the maximum response of 24.2% for 100 ppm NO{sub 2} gas concentration at an operating temperature of 200 °C with response and recovery times of 13 s and 140 s, respectively. Finally, the chemisorption mechanism of NO{sub 2} gas on the V{sub 2}O{sub 5} nanorods is discussed.

Leaf gas exchange characteristics of three neotropical mangrove species in response to varying hydroperiod

Science.gov (United States)

Krauss, Ken W.; Twilley, Robert R.; Doyle, Thomas W.; Gardiner, Emile S.

2006-01-01

We determined how different hydroperiods affected leaf gas exchange characteristics of greenhouse-grown seedlings (2002) and saplings (2003) of the mangrove species Avicennia germinans (L.) Stearn., Laguncularia racemosa (L.) Gaertn. f., and Rhizophora mangle L. Hydroperiod treatments included no flooding (unflooded), intermittent flooding (intermittent), and permanent flooding (flooded). Plants in the intermittent treatment were measured under both flooded and drained states and compared separately. In the greenhouse study, plants of all species maintained different leaf areas in the contrasting hydroperiods during both years. Assimilation–light response curves indicated that the different hydroperiods had little effect on leaf gas exchange characteristics in either seedlings or saplings. However, short-term intermittent flooding for between 6 and 22 days caused a 20% reduction in maximum leaf-level carbon assimilation rate, a 51% lower light requirement to attain 50% of maximum assimilation, and a 38% higher demand from dark respiration. Although interspecific differences were evident for nearly all measured parameters in both years, there was little consistency in ranking of the interspecific responses. Species by hydroperiod interactions were significant only for sapling leaf area. In a field study, R. mangle saplings along the Shark River in the Everglades National Park either demonstrated no significant effect or slight enhancement of carbon assimilation and water-use efficiency while flooded. We obtained little evidence that contrasting hydroperiods affect leaf gas exchange characteristics of mangrove seedlings or saplings over long time intervals; however, intermittent flooding may cause short-term depressions in leaf gas exchange. The resilience of mangrove systems to flooding, as demonstrated in the permanently flooded treatments, will likely promote photosynthetic and morphological adjustment to slight hydroperiod shifts in many settings..

Fast response of sprayed vanadium pentoxide (V2O5) nanorods towards nitrogen dioxide (NO2) gas detection

Science.gov (United States)

Mane, A. A.; Suryawanshi, M. P.; Kim, J. H.; Moholkar, A. V.

2017-05-01

The V2O5 nanorods have been successfully spray deposited at optimized substrate temperature of 400 °C onto the glass substrates using vanadium trichloride (VCl3) solution of different concentrations. The effect of solution concentration on the physicochemical and NO2 gas sensing properties of sprayed V2O5 nanorods is studied at different operating temperatures and gas concentrations. The XRD study reveals the formation of V2O5 having an orthorhombic symmetry. The FE-SEM micrographs show the nanorods-like morphology of V2O5. The AFM micrographs exhibit a well covered granular surface topography. For direct allowed transition, the band gap energy values are found to be decreased from 2.45 eV to 2.42 eV. The nanorods deposited with 30 mM solution concentration shows the maximum response of 24.2% for 100 ppm NO2 gas concentration at an operating temperature of 200 °C with response and recovery times of 13 s and 140 s, respectively. Finally, the chemisorption mechanism of NO2 gas on the V2O5 nanorods is discussed.

Responses to water stress of gas exchange and metabolites in Eucalyptus and Acacia spp.

Science.gov (United States)

Warren, Charles R; Aranda, Ismael; Cano, F Javier

2011-10-01

Studies of water stress commonly examine either gas exchange or leaf metabolites, and many fail to quantify the concentration of CO₂ in the chloroplasts (C(c)). We redress these limitations by quantifying C(c) from discrimination against ¹³CO₂ and using gas chromatography-mass spectrometry (GC-MS) for leaf metabolite profiling. Five Eucalyptus and two Acacia species from semi-arid to mesic habitats were subjected to a 2 month water stress treatment (Ψ(pre-dawn) = -1.7 to -2.3 MPa). Carbohydrates dominated the leaf metabolite profiles of species from dry areas, whereas organic acids dominated the metabolite profiles of species from wet areas. Water stress caused large decreases in photosynthesis and C(c), increases in 17-33 metabolites and decreases in 0-9 metabolites. In most species, fructose, glucose and sucrose made major contributions to osmotic adjustment. In Acacia, significant osmotic adjustment was also caused by increases in pinitol, pipecolic acid and trans-4-hydroxypipecolic acid. There were also increases in low-abundance metabolites (e.g. proline and erythritol), and metabolites that are indicative of stress-induced changes in metabolism [e.g. γ-aminobutyric acid (GABA) shunt, photorespiration, phenylpropanoid pathway]. The response of gas exchange to water stress and rewatering is rather consistent among species originating from mesic to semi-arid habitats, and the general response of metabolites to water stress is rather similar, although the specific metabolites involved may vary. © 2011 Blackwell Publishing Ltd.

Gas sensing properties of indium–gallium–zinc–oxide gas sensors in different light intensity

Directory of Open Access Journals (Sweden)

Kuen-Lin Chen

2015-06-01

Full Text Available We have successfully observed the change in indium–gallium–zinc–oxide (IGZO gas sensor sensitivity by controlling the light emitting diode (LED power under the same gas concentrations. The light intensity dependence of sensor properties is discussed. Different LED intensities obviously affected the gas sensor sensitivity, which decays with increasing LED intensity. High LED intensity decreases not only gas sensor sensitivity but also the response time (T90, response time constant (τres and the absorption rate per second. Low intensity irradiated to sensor causes high sensitivity, but it needs larger response time. Similar results were also observed in other kinds of materials such as TiO2. According to the results, the sensing properties of gas sensors can be modulated by controlling the light intensity.

Metallurgical response of an AISI 4140 steel to different plasma nitriding gas mixtures

Directory of Open Access Journals (Sweden)

Adão Felipe Oliveira Skonieski

2013-01-01

Full Text Available Plasma nitriding is a surface modification process that uses glow discharge to diffuse nitrogen atoms into the metallic matrix of different materials. Among the many possible parameters of the process, the gas mixture composition plays an important role, as it impacts directly the formed layer's microstructure. In this work an AISI 4140 steel was plasma nitrided under five different gas compositions. The plasma nitriding samples were characterized using optical and scanning electron microscopy, microhardness test, X-ray diffraction and GDOES. The results showed that there are significant microstructural and morphological differences on the formed layers depending on the quantity of nitrogen and methane added to the plasma nitriding atmosphere. Thicknesses of 10, 5 and 2.5 µm were obtained when the nitrogen content of the gas mixtures were varied. The possibility to obtain a compound layer formed mainly by γ'-Fe4N nitrides was also shown. For all studied plasma nitriding conditions, the presence of a compound layer was recognized as being the responsible to hinder the decarburization on the steel surface. The highest value of surface hardness - 1277HV - were measured in the sample which were nitrided with 3vol.% of CH4.

Comparison of information content of temporal response of chemoresistive gas sensor under three different temperature modulation regimes for gas detection of different feature reduction methods

Science.gov (United States)

Hosseini-Golgoo, S. M.; Salimi, F.; Saberkari, A.; Rahbarpour, S.

2017-12-01

In the present work the feature extraction of transient response of a resistive gas sensor under temperature cycling, temperature transient, and temperature combination methods were compared. So, the heater were stimulated by three pulse (cycling), ramp (transient) and staircase (combination) waveforms. The period or duration of all waves was equal to 40 s. Methanol, ethanol, 1-propanol, 1-butanol, toluene and acetone each at 11 different concentration levels in the range of 100 to 2000 ppm were used as the target gases. The utilized sensor was TGS-813 that made by Figaro Company. Recorded results were studied and heuristic features such as peak, rise time, slope and curvature of recorded responses were extracted for each heater waveform. Results showed that although application of this feature extraction method to all waveforms led to gas diagnoses, best results were achieved in the case of staircase waveform. The combination waveform had enough information to separate all examined target gases.

A new proposal for greenhouse gas emissions responsibility allocation: best available technologies approach.

Science.gov (United States)

Berzosa, Álvaro; Barandica, Jesús M; Fernández-Sánchez, Gonzalo

2014-01-01

In recent years, several methodologies have been developed for the quantification of greenhouse gas (GHG) emissions. However, determining who is responsible for these emissions is also quite challenging. The most common approach is to assign emissions to the producer (based on the Kyoto Protocol), but proposals also exist for its allocation to the consumer (based on an ecological footprint perspective) and for a hybrid approach called shared responsibility. In this study, the existing proposals and standards regarding the allocation of GHG emissions responsibilities are analyzed, focusing on their main advantages and problems. A new model of shared responsibility that overcomes some of the existing problems is also proposed. This model is based on applying the best available technologies (BATs). This new approach allocates the responsibility between the producers and the final consumers based on the real capacity of each agent to reduce emissions. The proposed approach is demonstrated using a simple case study of a 4-step life cycle of ammonia nitrate (AN) fertilizer production. The proposed model has the characteristics that the standards and publications for assignment of GHG emissions responsibilities demand. This study presents a new way to assign responsibilities that pushes all the actors in the production chain, including consumers, to reduce pollution. © 2013 SETAC.

Gas-ion laser with gas pressure maintenance means

International Nuclear Information System (INIS)

Thatcher, J.B.

1975-01-01

A gas-ion laser is described including means to maintain the ionizable gas in the laser cavity at a rather constant pressure over an extended period of time to significantly increase the useful life of the gas-ion laser. The gas laser includes a gas makeup system having a high pressure source or storage container and a regulating valve. The valve has a permeable solid state orifice member through which the gas flows from the high pressure source to the laser cavity to replenish the gas in the laser cavity and maintain the gas pressure in the cavity rather constant. The permeable orifice member is selected from a solid state material having a permeability that is variable in relation to the magnitude of the energy applied to the orifice member. The gas-ion laser has a valve operating means such as a heater for varying the applied energy such as thermal energy to the member to regulate the gas flow. Additionally, the gas-ion laser has a valve control means that is responsive to the gas pressure in the laser cavity for controlling the valve control means to maintain the pressure at a desired level. (U.S.)

FIN5 positively regulates far-red light responses in Arabidopsis thaliana

International Nuclear Information System (INIS)

Cho, D.S.; Hong, S.H.; Nam, H.G.; Soh, M.S.

2003-01-01

We report the characterization of a semi-dominant mutation fin5-1 (far-red insensitive 5-1) of Arabidopsis, which was isolated from genetic screening of phytochrome A (phyA) signaling components. Plants with the fin5-1 mutation exhibited a long hypocotyl phenotype when grown under far-red (FR) light, but not under red light. Physiological analyses implied that FIN5 might be differentially involved in diverse responses that are regulated by phyA under continuous FR light. Anthocyanin accumulation, gravitropic response of hypocotyl growth, and FR light-preconditioned blocking of greening were also impaired in the fin5-1 mutant, whereas photoperiodic floral induction was not, if at all, significantly affected. Moreover, light-regulated expression of the CHS, PORA and PsbS genes was attenuated in fin5-1 mutant plants, while the light-induced expression of CAB was normal. The mutation exhibited semi-dominance regarding control of hypocotyl growth in FR light. We suggest that FIN5 defines a novel branch in the network of phyA signaling in Arabidopsis. (author)

Oil and Gas Security. Emergency Response of IEA Countries - Denmark 2011 update

Energy Technology Data Exchange (ETDEWEB)

NONE

2011-08-12

This publication provides a detailed look at the specific systems in Denmark for responding to an oil supply crisis. Initially prepared as a chapter in the overarching publication on the emergency response mechanisms in various IEA member countries, the IEA has started a new cycle of reviews which now includes reviewing gas emergency policies. Rather than waiting for the completion of the current review cycle to renew the full larger publication, the IEA will be making available updates to the country chapters as these become available following the country's review.

Oil and Gas Security. Emergency Response of IEA Countries - Norway 2011 update

Energy Technology Data Exchange (ETDEWEB)

NONE

2011-08-12

This publication provides a detailed look at the specific systems in Norway for responding to an oil supply crisis. Initially prepared as a chapter in the overarching publication on the emergency response mechanisms in various IEA member countries, the IEA has started a new cycle of reviews which now includes reviewing gas emergency policies. Rather than waiting for the completion of the current review cycle to renew the full larger publication, the IEA will be making available updates to the country chapters as these become available following the country's review.

Oil and Gas Security. Emergency Response of IEA Countries - Poland 2011 update

Energy Technology Data Exchange (ETDEWEB)

NONE

2011-08-12

This publication provides a detailed look at the specific systems in Poland for responding to an oil supply crisis. Initially prepared as a chapter in the overarching publication on the emergency response mechanisms in various IEA member countries, the IEA has started a new cycle of reviews which now includes reviewing gas emergency policies. Rather than waiting for the completion of the current review cycle to renew the full larger publication, the IEA will be making available updates to the country chapters as these become available following the country's review.

Oil and Gas Security. Emergency Response of IEA Countries - Spain 2011 update

Energy Technology Data Exchange (ETDEWEB)

NONE

2011-08-12

This publication provides a detailed look at the specific systems in Spain for responding to an oil supply crisis. Initially prepared as a chapter in the overarching publication on the emergency response mechanisms in various IEA member countries, the IEA has started a new cycle of reviews which now includes reviewing gas emergency policies. Rather than waiting for the completion of the current review cycle to renew the full larger publication, the IEA will be making available updates to the country chapters as these become available following the country's review.

Oil and Gas Security. Emergency Response of IEA Countries - Italy 2010 update

Energy Technology Data Exchange (ETDEWEB)

NONE

2010-07-01

This publication provides a detailed look at the specific systems in Italy for responding to an oil supply crisis. Initially prepared as a chapter in the overarching publication on the emergency response mechanisms in various IEA member countries, the IEA has started a new cycle of reviews which now includes reviewing gas emergency policies. Rather than waiting for the completion of the current review cycle to renew the full larger publication, the IEA will be making available updates to the country chapters as these become available following the country's review.

Oil and Gas Security. Emergency Response of IEA Countries - Belgium 2010 update

Energy Technology Data Exchange (ETDEWEB)

NONE

2011-08-12

This publication provides a detailed look at the specific systems in Belgium for responding to an oil supply crisis. Initially prepared as a chapter in the overarching publication on the emergency response mechanisms in various IEA member countries, the IEA has started a new cycle of reviews which now includes reviewing gas emergency policies. Rather than waiting for the completion of the current review cycle to renew the full larger publication, the IEA will be making available updates to the country chapters as these become available following the country's review.

Oil and Gas Security. Emergency Response of IEA Countries - Portugal 2011 update

Energy Technology Data Exchange (ETDEWEB)

NONE

2011-08-12

This publication provides a detailed look at the specific systems in Portugal for responding to an oil supply crisis. Initially prepared as a chapter in the overarching publication on the emergency response mechanisms in various IEA member countries, the IEA has started a new cycle of reviews which now includes reviewing gas emergency policies. Rather than waiting for the completion of the current review cycle to renew the full larger publication, the IEA will be making available updates to the country chapters as these become available following the country's review.

Oil and Gas Security. Emergency Response of IEA Countries - Ireland 2011 update

Energy Technology Data Exchange (ETDEWEB)

NONE

2011-08-12

This publication provides a detailed look at the specific systems in Ireland for responding to an oil supply crisis. Initially prepared as a chapter in the overarching publication on the emergency response mechanisms in various IEA member countries, the IEA has started a new cycle of reviews which now includes reviewing gas emergency policies. Rather than waiting for the completion of the current review cycle to renew the full larger publication, the IEA will be making available updates to the country chapters as these become available following the country's review.

Oil and Gas Security. Emergency Response of IEA Countries - Canada 2010 update

Energy Technology Data Exchange (ETDEWEB)

NONE

2010-07-01

This publication provides a detailed look at the specific systems in Canada for responding to an oil supply crisis. Initially prepared as a chapter in the overarching publication on the emergency response mechanisms in various IEA member countries, the IEA has started a new cycle of reviews which now includes reviewing gas emergency policies. Rather than waiting for the completion of the current review cycle to renew the full larger publication, the IEA will be making available updates to the country chapters as these become available following the country's review.

Oil and Gas Security. Emergency Response of IEA Countries - Luxembourg 2010 update

Energy Technology Data Exchange (ETDEWEB)

NONE

2010-07-01

This publication provides a detailed look at the specific systems in Luxembourg for responding to an oil supply crisis. Initially prepared as a chapter in the overarching publication on the emergency response mechanisms in various IEA member countries, the IEA has started a new cycle of reviews which now includes reviewing gas emergency policies. Rather than waiting for the completion of the current review cycle to renew the full larger publication, the IEA will be making available updates to the country chapters as these become available following the country's review.

Remarkable separability of circulation response to Arctic sea ice loss and greenhouse gas forcing

Science.gov (United States)

McCusker, K. E.; Kushner, P. J.; Fyfe, J. C.; Sigmond, M.; Kharin, V. V.; Bitz, C. M.

2017-08-01

Arctic sea ice loss may influence midlatitude climate by changing large-scale circulation. The extent to which climate change can be understood as greenhouse gas-induced changes that are modulated by this loss depends on how additive the responses to the separate influences are. A novel sea ice nudging methodology in a fully coupled climate model reveals that the separate effects of doubled atmospheric carbon dioxide (CO2) concentrations and associated Arctic sea ice loss are remarkably additive and insensitive to the mean climate state. This separability is evident in several fields throughout most of the year, from hemispheric to synoptic scales. The extent to which the regional response to sea ice loss sometimes agrees with and sometimes cancels the response to CO2 is quantified. The separability of the responses might provide a means to better interpret the diverse array of modeling and observational studies of Arctic change and influence.

Agricultural demands for natural gas and liquified petroleum gas in the USA

International Nuclear Information System (INIS)

Uri, N.D.; Gill, M.

1992-01-01

This study endeavours to determine whether farmers adjust their consumption of natural gas and liquefied petroleum gas in response to changes in the unit price of energy. A demand model is specified and estimated. The conclusions suggest that the unit price of natural gas (liquefied petroleum gas) is a factor impacting the quantity of natural gas (liquefied petroleum gas) demanded by farmers, but there is no indication that other types of energy are substitutes for natural gas or liquefied petroleum gas. Additionally, the number of acres irrigated is an important factor driving the demand for natural gas and liquefied petroleum gas. Finally, the estimated models of natural gas and liquefied petroleum gas demand were structurally stable over the period 1971-1989. (author)

Gas response properties of citrate gel synthesized nanocrystalline MgFe{sub 2}O{sub 4}: Effect of sintering temperature

Energy Technology Data Exchange (ETDEWEB)

Patil, J.Y. [School of Physical Sciences, Solapur University Solapur-413255 (India); Mulla, I.S. [Emeritus Scientist (CSIR), Centre for Materials for Electronic Technology(C-MET) Pune-411 008 (India); Suryavanshi, S.S., E-mail: sssuryavanshi@rediffmail.com [School of Physical Sciences, Solapur University Solapur-413255 (India)

2013-02-15

Graphical abstract: Display Omitted Highlights: ► Synthesis of nanocrystalline MgFe{sub 2}O{sub 4} by economical citrate gel combustion method. ► Structural, morphological, and gas response properties of MgFe{sub 2}O{sub 4}. ► Enhancement in selectivity of MgFe{sub 2}O{sub 4} towards LPG with sintering temperature. ► Use of MgFe{sub 2}O{sub 4} to detect different gases at different operating temperatures. -- Abstract: Spinel type MgFe{sub 2}O{sub 4} material was synthesized by citrate gel combustion method. The effect of sintering temperature on structural, morphological, and gas response properties was studied. The powder X-ray diffraction pattern and transmission electron microscope study confirms nanocrystalline spinel structure of the synthesized powder. The material was tested for response properties to various reducing gases like liquid petroleum gas (LPG), acetone, ethanol, and ammonia. The results demonstrated n-type semiconducting behavior of MgFe{sub 2}O{sub 4} material. It was revealed that MgFe{sub 2}O{sub 4} sintered at 973 K was most sensitive to LPG at 648 K and to acetone at 498 K. However MgFe{sub 2}O{sub 4} sintered at 1173 K exhibited higher response and selectivity to LPG with marginal increase in the operating temperature. Furthermore, the sensor exhibited a fast response and a good recovery. It was observed that the particles size, porosity, and surface activity of the sensor material is affected by the sintering temperature.

Demographic response of Louisiana Waterthrush, a stream obligate songbird of conservation concern, to shale gas development

Science.gov (United States)

Frantz, Mack W.; Wood, Petra B.; Sheehan, James; George, Gregory

2018-01-01

Shale gas development continues to outpace the implementation of best management practices for wildlife affected by development. We examined demographic responses of the Louisiana Waterthrush (Parkesia motacilla) to shale gas development during 2009–2011 and 2013–2015 in a predominantly forested landscape in West Virginia, USA. Forest cover across the study area decreased from 95% in 2008 to 91% in 2015, while the area affected by shale gas development increased from 0.4% to 3.9%. We quantified nest survival and productivity, a source–sink threshold, riparian habitat quality, territory density, and territory length by monitoring 58.1 km of forested headwater streams (n = 14 streams). Across years, we saw annual variability in nest survival, with a general declining trend over time. Of 11 a priori models tested to explain nest survival (n = 280 nests), 4 models that included temporal, habitat, and shale gas covariates were supported, and 2 of these models accounted for most of the variation in daily nest survival rate. After accounting for temporal effects (rainfall, nest age, and time within season), shale gas development had negative effects on nest survival. Population-level nest productivity declined and individual productivity was lower in areas disturbed by shale gas development than in undisturbed areas, and a source–sink threshold suggested that disturbed areas were more at risk of being sink habitat. Riparian habitat quality scores, as measured by a U.S. Environmental Protection Agency index and a waterthrush-specific habitat suitability index, differed by year and were negatively related to the amount of each territory disturbed by shale gas development. Territory density was not related to the amount of shale gas disturbance, but decreased over time as territory lengths increased. Overall, our results suggest a decline in waterthrush site quality as shale gas development increases, despite relatively small site-wide forest loss.

The persistence of the gravity signal in flax roots

Science.gov (United States)

Hasenstein, Karl H.

Although the presentation time of gravitropism has been studied, no data exist as to how long a reorientation stimulus affects the gravitropic response of a root. We tested the duration of gravitropic curvature in roots of Linum usitatissimum after reversing a one hour, 90 degree gravistimulus by increasing time intervals in vertical orientation before clinorotating the roots and acquiring infrared digital images. Clinorotation was performed either parallel or perpendicular to the gravity vector. Under either condition the gravistimulus affected curvature during clinorotation only between two to three minutes. Maximal curvature after one minute of vertical reorientation was 15 degrees within one hour. After three minutes in vertical orientation the observed curvature was not statistically different from vertically growing roots. In both orientations, maximum curvature occurred after 1hr. Perpendicular (horizontal) clinorotation showed decreasing curvature with increasing reorientation time. Parallel (vertical) clinorotation resulted in greater variability to the reorientation time. These data indicate that the gravity stimulus operates essentially memory free and that clinorotation affects the gravity response. Therefore all aspects of clinorotation need to be studied before an assessment of clinostats for the simulation of microgravity is possible and a time limit for memory effects of mechanostimulation can be determined.

Optospectroscopic Detection of Primary Reactions Associated with the Graviperception of Phycomyces. Effects of Micro- and Hypergravity1

Science.gov (United States)

Schmidt, Werner; Galland, Paul

2004-01-01

The graviperception of sporangiophores of the fungus Phycomyces blakesleeanus involves gravity-induced absorbance changes (GIACs) that represent primary responses of gravitropism (Schmidt and Galland, 2000). GIACs (ΔA460–665) of sporangiophores were measured in vivo with a micro-dual wavelength spectrometer at 460 and 665 nm. Sporangiophores that were placed horizontally displayed an instant increase of the GIACs while the return to the vertical position elicited an instant decrease. The GIACs are specific for graviperception, because they were absent in a gravitropism mutant with a defective madJ gene. During parabola flights hypergravity (1.8g) elicited a decrease of the GIACs, while microgravity (0 ± 3 × 10−2g) elicited an instant increase. Hypergravity that was generated in a centrifuge (1.5–6.5g) elicited also a decrease of the GIACs that saturated at about 5g. The GIACs have a latency of about 20 ms or shorter and are thus the fastest graviresponses ever measured for fungi, protists, and plants. The threshold for eliciting the GIACs is near 3 × 10−2g, which coincides numerically with the threshold for gravitropic bending. In contrast to gravitropic bending, which requires long-term stimulation, GIACs can be elicited by stimuli as short as 20 to 100 ms, leading to an extremely low threshold dose (acceleration × time) of about 3 × 10−3g s, a value, which is four orders of magnitude below the ones described for other organisms and which makes the GIACs of Phycomyces blakesleeanus the most sensitive gravi-response in literature. PMID:15122026

Improved gas mixtures for gas-filled particle detectors

Science.gov (United States)

Christophorou, L.G.; McCorkle, D.L.; Maxey, D.V.; Carter, J.G.

Improved binary and tertiary gas mixture for gas-filled particle detectors are provided. The components are chosen on the basis of the principle that the first component is one gas or mixture of two gases having a large electron scattering cross section at energies of about 0.5 eV and higher, and the second component is a gas (Ar) having a very small cross section at and below about 0.5 eV; whereby fast electrons in the gaseous mixture are slowed into the energy range of about 0.5 eV where the cross section for the mixture is small and hence the electron mean free path is large. The reduction in both the cross section and the electron energy results in an increase in the drift velocity of the electrons in the gas mixtures over that for the separate components for a range of E/P (pressure-reduced electron field) values. Several gas mixtures are provided that provide faster response in gas-filled detectors for convenient E/P ranges as compared with conventional gas mixtures.

Response Optimization of a Chemical Gas Sensor Array using Temperature Modulation

Directory of Open Access Journals (Sweden)

Cristhian Durán

2018-04-01

Full Text Available This paper consists of the design and implementation of a simple conditioning circuit to optimize the electronic nose performance, where a temperature modulation method was applied to the heating resistor to study the sensor’s response and confirm whether they are able to make the discrimination when exposed to different volatile organic compounds (VOC’s. This study was based on determining the efficiency of the gas sensors with the aim to perform an electronic nose, improving the sensitivity, selectivity and repeatability of the measuring system, selecting the type of modulation (e.g., pulse width modulation for the analytes detection (i.e., Moscatel wine samples (2% of alcohol and ethyl alcohol (70%. The results demonstrated that by using temperature modulation technique to the heating resistors, it is possible to realize the discrimination of VOC’s in fast and easy way through a chemical sensors array. Therefore, a discrimination model based on principal component analysis (PCA was implemented to each sensor, with data responses obtaining a variance of 94.5% and accuracy of 100%.

Climate Response to Negative Greenhouse Gas Radiative Forcing in Polar Winter

Science.gov (United States)

Flanner, M. G.; Huang, X.; Chen, X.; Krinner, G.

2018-02-01

Greenhouse gas (GHG) additions to Earth's atmosphere initially reduce global outgoing longwave radiation, thereby warming the planet. In select environments with temperature inversions, however, increased GHG concentrations can actually increase local outgoing longwave radiation. Negative top of atmosphere and effective radiative forcing (ERF) from this situation give the impression that local surface temperatures could cool in response to GHG increases. Here we consider an extreme scenario in which GHG concentrations are increased only within the warmest layers of winter near-surface inversions of the Arctic and Antarctic. We find, using a fully coupled Earth system model, that the underlying surface warms despite the GHG addition exerting negative ERF and cooling the troposphere in the vicinity of the GHG increase. This unique radiative forcing and thermal response is facilitated by the high stability of the polar winter atmosphere, which inhibit thermal mixing and amplify the impact of surface radiative forcing on surface temperature. These findings also suggest that strategies to exploit negative ERF via injections of short-lived GHGs into inversion layers would likely be unsuccessful in cooling the planetary surface.

The common HAQ STING variant impairs cGAS-dependent antibacterial responses and is associated with susceptibility to Legionnaires' disease in humans.

Directory of Open Access Journals (Sweden)

Juan S Ruiz-Moreno

2018-01-01

Full Text Available The cyclic GMP-AMP synthase (cGAS-STING pathway is central for innate immune sensing of various bacterial, viral and protozoal infections. Recent studies identified the common HAQ and R232H alleles of TMEM173/STING, but the functional consequences of these variants for primary infections are unknown. Here we demonstrate that cGAS- and STING-deficient murine macrophages as well as human cells of individuals carrying HAQ TMEM173/STING were severely impaired in producing type I IFNs and pro-inflammatory cytokines in response to Legionella pneumophila, bacterial DNA or cyclic dinucleotides (CDNs. In contrast, R232H attenuated cytokine production only following stimulation with bacterial CDN, but not in response to L. pneumophila or DNA. In a mouse model of Legionnaires' disease, cGAS- and STING-deficient animals exhibited higher bacterial loads as compared to wild-type mice. Moreover, the haplotype frequency of HAQ TMEM173/STING, but not of R232H TMEM173/STING, was increased in two independent cohorts of human Legionnaires' disease patients as compared to healthy controls. Our study reveals that the cGAS-STING cascade contributes to antibacterial defense against L. pneumophila in mice and men, and provides important insight into how the common HAQ TMEM173/STING variant affects antimicrobial immune responses and susceptibility to infection.ClinicalTrials.gov DRKS00005274, German Clinical Trials Register.

The common HAQ STING variant impairs cGAS-dependent antibacterial responses and is associated with susceptibility to Legionnaires' disease in humans.

Science.gov (United States)

Ruiz-Moreno, Juan S; Hamann, Lutz; Shah, Javeed A; Verbon, Annelies; Mockenhaupt, Frank P; Puzianowska-Kuznicka, Monika; Naujoks, Jan; Sander, Leif E; Witzenrath, Martin; Cambier, John C; Suttorp, Norbert; Schumann, Ralf R; Jin, Lei; Hawn, Thomas R; Opitz, Bastian

2018-01-01

The cyclic GMP-AMP synthase (cGAS)-STING pathway is central for innate immune sensing of various bacterial, viral and protozoal infections. Recent studies identified the common HAQ and R232H alleles of TMEM173/STING, but the functional consequences of these variants for primary infections are unknown. Here we demonstrate that cGAS- and STING-deficient murine macrophages as well as human cells of individuals carrying HAQ TMEM173/STING were severely impaired in producing type I IFNs and pro-inflammatory cytokines in response to Legionella pneumophila, bacterial DNA or cyclic dinucleotides (CDNs). In contrast, R232H attenuated cytokine production only following stimulation with bacterial CDN, but not in response to L. pneumophila or DNA. In a mouse model of Legionnaires' disease, cGAS- and STING-deficient animals exhibited higher bacterial loads as compared to wild-type mice. Moreover, the haplotype frequency of HAQ TMEM173/STING, but not of R232H TMEM173/STING, was increased in two independent cohorts of human Legionnaires' disease patients as compared to healthy controls. Our study reveals that the cGAS-STING cascade contributes to antibacterial defense against L. pneumophila in mice and men, and provides important insight into how the common HAQ TMEM173/STING variant affects antimicrobial immune responses and susceptibility to infection. ClinicalTrials.gov DRKS00005274, German Clinical Trials Register.

The common HAQ STING variant impairs cGAS-dependent antibacterial responses and is associated with susceptibility to Legionnaires’ disease in humans

Science.gov (United States)

Hamann, Lutz; Verbon, Annelies; Mockenhaupt, Frank P.; Puzianowska-Kuznicka, Monika; Naujoks, Jan; Sander, Leif E.; Witzenrath, Martin; Schumann, Ralf R.; Hawn, Thomas R.

2018-01-01

The cyclic GMP-AMP synthase (cGAS)-STING pathway is central for innate immune sensing of various bacterial, viral and protozoal infections. Recent studies identified the common HAQ and R232H alleles of TMEM173/STING, but the functional consequences of these variants for primary infections are unknown. Here we demonstrate that cGAS- and STING-deficient murine macrophages as well as human cells of individuals carrying HAQ TMEM173/STING were severely impaired in producing type I IFNs and pro-inflammatory cytokines in response to Legionella pneumophila, bacterial DNA or cyclic dinucleotides (CDNs). In contrast, R232H attenuated cytokine production only following stimulation with bacterial CDN, but not in response to L. pneumophila or DNA. In a mouse model of Legionnaires’ disease, cGAS- and STING-deficient animals exhibited higher bacterial loads as compared to wild-type mice. Moreover, the haplotype frequency of HAQ TMEM173/STING, but not of R232H TMEM173/STING, was increased in two independent cohorts of human Legionnaires’ disease patients as compared to healthy controls. Our study reveals that the cGAS-STING cascade contributes to antibacterial defense against L. pneumophila in mice and men, and provides important insight into how the common HAQ TMEM173/STING variant affects antimicrobial immune responses and susceptibility to infection. Trial registration ClinicalTrials.gov DRKS00005274, German Clinical Trials Register PMID:29298342

Selling gas, selling services

International Nuclear Information System (INIS)

Moncel, V.

1999-01-01

Traditionally, the commercial activities of gas companies have been limited almost exclusively to the sale of gas. However, several socioeconomic factors specific to the gas industry, such as increasing customer expectations, competition between gas operators, a growing emphasis on services in many companies and the opening of public monopolies to competition, will bring inevitable change. Moreover, these developments coincide with imminent gas market opening. In response to the changing situation, the gas industry will seek to develop a range of multi-service offers, probably through external partnerships. (authors)

Physiological and behavioral responses of poultry exposed to gas-filled high expansion foam.

Science.gov (United States)

McKeegan, D E F; Reimert, H G M; Hindle, V A; Boulcott, P; Sparrey, J M; Wathes, C M; Demmers, T G M; Gerritzen, M A

2013-05-01

Disease control measures require poultry to be killed on farms to minimize the risk of disease being transmitted to other poultry and, in some cases, to protect public health. We assessed the welfare implications for poultry of the use of high-expansion gas-filled foam as a potentially humane, emergency killing method. In laboratory trials, broiler chickens, adult laying hens, ducks, and turkeys were exposed to air-, N2-, or CO2-filled high expansion foam (expansion ratio 300:1) under standardized conditions. Birds were equipped with sensors to measure cardiac and brain activity, and measurements of oxygen concentration in the foam were carried out. Initial behavioral responses to foam were not pronounced but included headshakes and brief bouts of wing flapping. Both N2- and CO2-filled foam rapidly induced ataxia/loss of posture and vigorous wing flapping in all species, characteristic of anoxic death. Immersion in air-filled, high expansion foam had little effect on physiology or behavior. Physiological responses to both N2- and CO2-filled foam were characterized by a pronounced bradyarrythymia and a series of consistent changes in the appearance of the electroencephalogram. These were used to determine an unequivocal time to loss of consciousness in relation to submersion. Mean time to loss of consciousness was 30 s in hens and 18 s in broilers exposed to N2-filled foam, and 16 s in broilers, 1 s in ducks, and 15 s in turkeys exposed to CO2-filled foam. Euthanasia achieved with anoxic foam was particularly rapid, which is explained by the very low oxygen concentrations (below 1%) inside the foam. Physiological observations and postmortem examination showed that the mode of action of high expansion, gas-filled foam is anoxia, not occlusion of the airway. These trials provide proof-of-principle that submersion in gas-filled, high expansion foam provides a rapid and highly effective method of euthanasia, which may have potential to provide humane emergency killing

Hydrogen Detection With a Gas Sensor Array – Processing and Recognition of Dynamic Responses Using Neural Networks

Directory of Open Access Journals (Sweden)

Gwiżdż Patryk

2015-03-01

Full Text Available An array consisting of four commercial gas sensors with target specifications for hydrocarbons, ammonia, alcohol, explosive gases has been constructed and tested. The sensors in the array operate in the dynamic mode upon the temperature modulation from 350°C to 500°C. Changes in the sensor operating temperature lead to distinct resistance responses affected by the gas type, its concentration and the humidity level. The measurements are performed upon various hydrogen (17-3000 ppm, methane (167-3000 ppm and propane (167-3000 ppm concentrations at relative humidity levels of 0-75%RH. The measured dynamic response signals are further processed with the Discrete Fourier Transform. Absolute values of the dc component and the first five harmonics of each sensor are analysed by a feed-forward back-propagation neural network. The ultimate aim of this research is to achieve a reliable hydrogen detection despite an interference of the humidity and residual gases.

Oil and Gas Security. Emergency Response of IEA Countries - Czech Republic 2010 update

Energy Technology Data Exchange (ETDEWEB)

NONE

2010-07-01

This publication provides a detailed look at the specific systems in Czech Republic for responding to an oil supply crisis. Initially prepared as a chapter in the overarching publication on the emergency response mechanisms in various IEA member countries, the IEA has started a new cycle of reviews which now includes reviewing gas emergency policies. Rather than waiting for the completion of the current review cycle to renew the full larger publication, the IEA will be making available updates to the country chapters as these become available following the country's review.

Oil and Gas Security. Emergency Response of IEA Countries - Slovak Republic 2011 update

Energy Technology Data Exchange (ETDEWEB)

NONE

2011-08-12

This publication provides a detailed look at the specific systems in Slovak Republic for responding to an oil supply crisis. Initially prepared as a chapter in the overarching publication on the emergency response mechanisms in various IEA member countries, the IEA has started a new cycle of reviews which now includes reviewing gas emergency policies. Rather than waiting for the completion of the current review cycle to renew the full larger publication, the IEA will be making available updates to the country chapters as these become available following the country's review.

Oil and Gas Security. Emergency Response of IEA Countries - United Kingdom 2010 update

Energy Technology Data Exchange (ETDEWEB)

NONE

2010-07-01

This publication provides a detailed look at the specific systems in United Kingdom for responding to an oil supply crisis. Initially prepared as a chapter in the overarching publication on the emergency response mechanisms in various IEA member countries, the IEA has started a new cycle of reviews which now includes reviewing gas emergency policies. Rather than waiting for the completion of the current review cycle to renew the full larger publication, the IEA will be making available updates to the country chapters as these become available following the country's review.

Oil and Gas Security. Emergency Response of IEA Countries - New Zealand 2010 update

Energy Technology Data Exchange (ETDEWEB)

NONE

2010-07-01

This publication provides a detailed look at the specific systems in New Zealand for responding to an oil supply crisis. Initially prepared as a chapter in the overarching publication on the emergency response mechanisms in various IEA member countries, the IEA has started a new cycle of reviews which now includes reviewing gas emergency policies. Rather than waiting for the completion of the current review cycle to renew the full larger publication, the IEA will be making available updates to the country chapters as these become available following the country's review.

The microtubule associated protein END BINDING 1 represses root responses to mechanical cues.

Science.gov (United States)

Gleeson, Laura; Squires, Shannon; Bisgrove, Sherryl R

2012-05-01

The ability of roots to navigate around rocks and other debris as they grow through the soil requires a mechanism for detecting and responding to input from both touch and gravity sensing systems. The microtubule associated protein END BINDING 1b (EB1b) is involved in this process as mutants have defects responding to combinations of touch and gravity cues. This study investigates the role of EB1b in root responses to mechanical cues. We find that eb1b-1 mutant roots exhibit an increase over wild type in their response to touch and that the expression of EB1b genes in transgenic mutants restores the response to wild type levels, indicating that EB1b is an inhibitor of the response. Mutant roots are also hypersensitive to increased levels of mechanical stimulation, revealing the presence of another process that activates the response. These findings are supported by analyses of double mutants between eb1b-1 and seedlings carrying mutations in PHOSPHOGLUCOMUTASE (PGM), ALTERED RESPONSE TO GRAVITY1 (ARG1), or TOUCH3 (TCH3), genes that encode proteins involved in gravity sensing, signaling, or touch responses, respectively. A model is proposed in which root responses to mechanical cues are modulated by at least two competing regulatory processes, one that promotes touch-mediated growth and another, regulated by EB1b, which dampens root responses to touch and enhances gravitropism. © 2012. Published by Elsevier Ireland Ltd. All rights reserved.

Medium-induced change of the optical response of metal clusters in rare-gas matrices

Science.gov (United States)

Xuan, Fengyuan; Guet, Claude

2017-10-01

Interaction with the surrounding medium modifies the optical response of embedded metal clusters. For clusters from about ten to a few hundreds of silver atoms, embedded in rare-gas matrices, we study the environment effect within the matrix random phase approximation with exact exchange (RPAE) quantum approach, which has proved successful for free silver clusters. The polarizable surrounding medium screens the residual two-body RPAE interaction, adds a polarization term to the one-body potential, and shifts the vacuum energy of the active delocalized valence electrons. Within this model, we calculate the dipole oscillator strength distribution for Ag clusters embedded in helium droplets, neon, argon, krypton, and xenon matrices. The main contribution to the dipole surface plasmon red shift originates from the rare-gas polarization screening of the two-body interaction. The large size limit of the dipole surface plasmon agrees well with the classical prediction.

Transient response simulation of gas separation membrane module for an atmosphere detritiation system

International Nuclear Information System (INIS)

Sugiyama, Takahiko; Tanaka, Masahiro; Munakata, Kenzo; Yamamoto, Ichiro

2012-01-01

Transient response of a gas separation membrane module for the atmosphere detritiation system was numerically simulated with a mass transfer model. The module contains thousands of hollow fiber type polyimide membranes. The simulation model took into account permeation of water vapor through the dense layer of the membrane, diffusive transfer through the porous support layer and adsorption/desorption of water vapor into the matrix of the porous layer. The slow responses of the water vapor concentration in the retentate and the permeation rate were well reproduced by the present simulation, and transient changes in a follow fiber membrane were investigated in detail. The inventory and the mean residence time of water vapor at 303 K were estimated for the commercial membrane module (UMS-B2, Ube industries, Ltd.) as 5.7 × 10 −3 mol and 380 s, respectively.

Do circulating long non-coding RNAs (lncRNAs) (LincRNA-p21, GAS 5, HOTAIR) predict the treatment response in patients with head and neck cancer treated with chemoradiotherapy?

Science.gov (United States)

Fayda, Merdan; Isin, Mustafa; Tambas, Makbule; Guveli, Murat; Meral, Rasim; Altun, Musa; Sahin, Dilek; Ozkan, Gozde; Sanli, Yasemin; Isin, Husniye; Ozgur, Emre; Gezer, Ugur

2016-03-01

Long non-coding RNAs (lncRNAs) have been shown to be aberrantly expressed in head and neck cancer (HNC). The aim of the present study was to evaluate plasma levels of three lncRNA molecules (lincRNA-p21, GAS5, and HOTAIR) in the treatment response in HNC patients treated with radical chemoradiotherapy (CRT). Forty-one patients with HNC were enrolled in the study. Most of the patients had nasopharyngeal carcinoma (n = 27, 65.9 %) and locally advanced disease. Blood was drawn at baseline and treatment evaluation 4.5 months after therapy. lncRNAs in plasma were measured by semiquantitative PCR. Treatment response was evaluated according to clinical examination, RECIST and PERCIST criteria based on magnetic resonance imaging (MRI), and positron emission tomography with computed tomography (PET/CT) findings. Complete response (CR) rates were 73.2, 36.6, and 50 % for clinical investigation, PET/CT-, or MRI-based response evaluation, respectively. Predictive value of lncRNAs was investigated in patients with CR vs. those with partial response (PR)/progressive disease (PD). We found that post-treatment GAS5 levels in patients with PR/PD were significantly higher compared with patients with CR based on clinical investigation (p = 0.01). Receiver operator characteristic (ROC) analysis showed that at a cutoff value of 0.3 of GAS5, sensitivity and specificity for clinical tumor response were 82 and 77 %, respectively. Interestingly, pretreatment GAS5 levels were significantly increased in patients with PR/PD compared to those with CR upon MRI-based response evaluation (p = 0.042). In contrast to GAS5, pretreatment or post-treatment lincRNA-p21 and HOTAIR levels were not informative for treatment response. Our results suggest that circulating GAS5 could be a biomarker in predicting treatment response in HNC patients.

Human plasmacytoid dentritic cells elicit a Type I Interferon response by sensing DNA via the cGAS-STING signaling pathway.

Science.gov (United States)

Bode, Christian; Fox, Mario; Tewary, Poonam; Steinhagen, Almut; Ellerkmann, Richard K; Klinman, Dennis; Baumgarten, Georg; Hornung, Veit; Steinhagen, Folkert

2016-07-01

Plasmacytoid dendritic cells (pDCs) are a major source of type I interferon (IFN) and are important for host defense by sensing microbial DNA via TLR9. pDCs also play a critical role in the pathogenesis of IFN-driven autoimmune diseases. Yet, this autoimmune reaction is caused by the recognition of self-DNA and has been linked to TLR9-independent pathways. Increasing evidence suggests that the cytosolic DNA receptor cyclic GMP-AMP (cGAMP) synthase (cGAS) is a critical component in the detection of pathogens and contributes to autoimmune diseases. It has been shown that binding of DNA to cGAS results in the synthesis of cGAMP and the subsequent activation of the stimulator of interferon genes (STING) adaptor to induce IFNs. Our results show that the cGAS-STING pathway is expressed and activated in human pDCs by cytosolic DNA leading to a robust type I IFN response. Direct activation of STING by cyclic dinucleotides including cGAMP also activated pDCs and knockdown of STING abolished this IFN response. These results suggest that pDCs sense cytosolic DNA and cyclic dinucleotides via the cGAS-STING pathway and that targeting this pathway could be of therapeutic interest. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Fast response time alcohol gas sensor using nanocrystalline F ...

Indian Academy of Sciences (India)

been used in gas sensor applications, i.e. adsorption ability, catalytic ... sity, as well as grain boundary alteration (Yamazoe 1991;. 521 ... oxide surface using a catalyst layer or gas filter layer. Shukla .... mobility and sheet resistance were measured using resisti- .... ation considerably reduces the conversion efficiency in flat.

Graviresponsiveness and abscisic-acid content of roots of carotenoid-deficient mutants of Zea mays L

Science.gov (United States)

Moore, R.; Smith, J. D.

1985-01-01

The abscisic-acid (ABA) content of roots of the carotenoid-deficient w-3, vp-5, and vp-7 mutants of Z. mays was analyzed using gas chromatography-mass spectrometry with an analysis sensitivity of 6 ng ABA g-1 fresh weight (FW). Roots of normal seedlings of the same lines were characterized by the following amounts of ABA (as ng ABA g-1 FW, +/- standard deviation): w-3, 279 +/- 43; vp-5, 237 +/- 26; vp-7, 338 +/- 61. We did not detect any ABA in roots of any of the mutants. Thus, the lack of carotenoids in these mutants correlated positively with the apparent absence of ABA. Primary roots of normal and mutant seedlings were positively gravitropic, with no significant differences in the curvatures of roots of normal as compared with mutant seedlings. These results indicate that ABA 1) is synthesized in maize roots via the carotenoid pathway, and 2) is not necessary for positive gravitropism by primary roots of Z. mays.

An investigation of the matrix sensitivity of refinery gas analysis using gas chromatography with flame ionisation detection.

Science.gov (United States)

Ferracci, Valerio; Brown, Andrew S; Harris, Peter M; Brown, Richard J C

2015-02-27

The response of a flame ionisation detector (FID) on a gas chromatograph to methane, ethane, propane, i-butane and n-butane in a series of multi-component refinery gas standards was investigated to assess the matrix sensitivity of the instrument. High-accuracy synthetic gas standards, traceable to the International System of Units, were used to minimise uncertainties. The instrument response exhibited a small dependence on the component amount fraction: this behaviour, consistent with that of another FID, was thoroughly characterised over a wide range of component amount fractions and was shown to introduce a negligible bias in the analysis of refinery gas samples, provided a suitable reference standard is employed. No significant effects of the molar volume, density and viscosity of the gas mixtures on the instrument response were observed, indicating that the FID is suitable for the analysis of refinery gas mixtures over a wide range of component amount fractions provided that appropriate drift-correction procedures are employed. Copyright © 2015 Elsevier B.V. All rights reserved.

Metal oxide-based gas sensor and microwave broad-band measurements: an innovative approach to gas sensing

International Nuclear Information System (INIS)

Jouhannaud, J; Rossignol, J; Stuerga, D

2007-01-01

We outline the development of a gas sensor using microwave technology (0.3 MHz to 3 GHz). The sensor is a coaxial structure into which is introduced a sensitive material. An electromagnetic field (microwave), sent out through the sensor by a vectorial network analyzer, solicits the sensitive material exposed to a gas. The observed variation in the sensor response is due to the variation in the adsorption of this gas. SrTiO 3 , demonstrated to be the highly sensitive to water vapour, is exposed to different gases (saturated vapour of water, ethanol and toluene). The response of the sensor is quantitative and typical for each gas. This method of measurement leads to the development of an alternative to the current gas sensor

Effect of cage vs. floor litter environments on the pulmonary hypertensive response to intravenous endotoxin and on blood-gas values in broilers.

Science.gov (United States)

Wang, W; Erf, G F; Wideman, R F

2002-11-01

Intravenous endotoxin has been shown to trigger a delayed pulmonary hypertensive response that varies widely in magnitude and duration among individual broilers. It was proposed that this individual variability may reflect immunological differences acquired during previous respiratory challenges that might have subsequently altered the endotoxin-initiated biochemical cascade. In Experiment 1, we tested the hypothesis that, when compared with broilers reared in clean stainless steel cages (Cage group), broilers reared on floor litter (Floor group) should experience a greater respiratory challenge and therefore may consistently exhibit a more enhanced pulmonary hypertensive response to intravenous endotoxin. Birds in the Cage group were grown in stainless steel cages at a low density (72 birds/8 m2 chamber), and fecal and dander materials were removed daily. Birds in the Floor group were reared on wood-shavings litter at a higher density (110 birds/8 m2 chamber). Pulmonary and systemic mean arterial pressures and blood-gas values were evaluated prior to and following the intravenous administration of 1 mg Salmonella typhimurium endotoxin. Broilers in the Floor and Cage groups exhibited pulmonary hypertensive responses to endotoxin that were very similar in terms of time of onset, duration, and magnitude, as well as variability in the response among individuals. Systemic hypotension also developed similarly in both groups following endotoxin injection. Blood-gas values indicated that the partial pressure of CO2 and the HCO3- concentration in arterial blood were higher (P broilers, and confirmed the negative impact of floor rearing on blood-gas values. We conclude that broilers reared on the floor inhaled litter dust and noxious fumes, which impaired pulmonary gas exchange and increased the arterial partial pressure of CO2 when compared with broilers reared in clean stainless steel cages. Nevertheless, the pulmonary hypertensive response to endotoxin did not differ

The Gas Congress

International Nuclear Information System (INIS)

2009-01-01

This document is published before a congress which will address the struggle against climate change, the security of the gas supply chain, the responses of energy groups to environmental and economic challenges, the opening of the gas market, the European energy policy, the future role of gas in the third industrial revolution, and the security of gas supplies. After an introduction briefly discussing these issues and the impacts of the French 'Grenelle de l'Environnement' and the struggle against climate change for gas production and consumption, several interviews are proposed with actors belonging to the AFG (Association Francaise du Gaz), ADEME, European Commission, Total, GDF Suez, other professional bodies, or local communities

The hormone response element mimic sequence of GAS5 lncRNA is sufficient to induce apoptosis in breast cancer cells

Science.gov (United States)

Pickard, Mark R.; Williams, Gwyn T.

2016-01-01

Growth arrest-specific 5 (GAS5) lncRNA promotes apoptosis, and its expression is down-regulated in breast cancer. GAS5 lncRNA is a decoy of glucocorticoid/related receptors; a stem-loop sequence constitutes the GAS5 hormone response element mimic (HREM), which is essential for the regulation of breast cancer cell apoptosis. This preclinical study aimed to determine if the GAS5 HREM sequence alone promotes the apoptosis of breast cancer cells. Nucleofection of hormone-sensitive and –insensitive breast cancer cell lines with a GAS5 HREM DNA oligonucleotide increased both basal and ultraviolet-C-induced apoptosis, and decreased culture viability and clonogenic growth, similar to GAS5 lncRNA. The HREM oligonucleotide demonstrated similar sequence specificity to the native HREM for its functional activity and had no effect on endogenous GAS5 lncRNA levels. Certain chemically modified HREM oligonucleotides, notably DNA and RNA phosphorothioates, retained pro-apoptotic. activity. Crucially the HREM oligonucleotide could overcome apoptosis resistance secondary to deficient endogenous GAS5 lncRNA levels. Thus, the GAS5 lncRNA HREM sequence alone is sufficient to induce apoptosis in breast cancer cells, including triple-negative breast cancer cells. These findings further suggest that emerging knowledge of structure/function relationships in the field of lncRNA biology can be exploited for the development of entirely novel, oligonucleotide mimic-based, cancer therapies. PMID:26862727

75 Easy Life Science Demonstrations. Teacher Book.

Science.gov (United States)

Kardos, Thomas

This book is a collection of life science classroom demonstrations. Explanations that review key concepts are included. Topics are: stimulus and response; gravitropism; phototropism; living organisms; carbon dioxide; gases emitted by plants; greenhouse effect; stomata; transpiration; leaf skeletons; seed growth; water evaporation in plants; carbon…

Natural gas market assessment. Canadian natural gas market mechanisms: Recent experiences and developments

International Nuclear Information System (INIS)

1993-11-01

The increase in natural gas demand and the associated expansions of most of the pipeline systems serving western Canada have reduced the excess deliverability or excess productive capacity that existed at the time of deregulation of the natural gas industry in 1985. Based on an industry survey, the responses of natural gas buyers and sellers to recent supply difficulties are described. Specific production, transportation, and contractual difficulties were encountered in winter 1992/93 as production was stretched to meet record levels of demand during periods of very cold temperatures and as short-term spot prices reached very high levels. Problems at this time included wellhead freezeups, pipeline outages, and inadequate contract terms and conditions. Methods used to maintain gas flows to end users are reviewed, including a discussion of force majeure, spot gas purchases, storage, supply curtailment, and special loan arrangements. In 1992/93, in most instances where the responsibility fell on the end-user to solve the supply problem, the difficulty was shifted to local distribution companies who have traditionally had more experience with such situations. No cases were identified where either a firm or interruptible end-user was forced to curtail gas consumption because of inadequate supply. New market mechanisms are emerging that will enable buyers and sellers of western Canadian gas to avoid many of the problems encountered in 1992/93. These include prearranged backstopping arrangements, short-term spot markets, access to other gas basins, standardized gas contracts, electronic trading, and price risk management tools. 11 figs

Nano-Hydroxyapatite Thick Film Gas Sensors

International Nuclear Information System (INIS)

Khairnar, Rajendra S.; Mene, Ravindra U.; Munde, Shivaji G.; Mahabole, Megha P.

2011-01-01

In the present work pure and metal ions (Co and Fe) doped hydroxyapatite (HAp) thick films have been successfully utilized to improve the structural, morphological and gas sensing properties. Nanocrystalline HAp powder is synthesized by wet chemical precipitation route, and ion exchange process is employed for addition of Co and Fe ions in HAp matrix. Moreover, swift heavy ion irradiation (SHI) technique is used to modify the surface of pure and metal ion exchanged HAp with various ion fluence. The structural investigation of pure and metal ion exchanged HAp thick films are carried out using X-ray diffraction and the presence of functional group is observed by means FTIR spectroscopy. Furthermore, surface morphology is visualized by means of SEM and AFM analysis. CO gas sensing study is carried out for, pure and metal ions doped, HAp thick films with detail investigation on operating temperature, response/recovery time and gas uptake capacity. The surface modifications of sensor matrix by SHI enhance the gas response, response/recovery and gas uptake capacity. The significant observation is here to note that, addition of Co and Fe in HAp matrix and surface modification by SHI improves the sensing properties of HAp films drastically resulting in gas sensing at relatively lower temperatures.

Method of controlling weld chamber purge and cover gas atmosphere

International Nuclear Information System (INIS)

Yeo, D.

1992-01-01

A method of controlling the gas atmosphere in a welding chamber includes detecting the absence of a fuel rod from the welding chamber and, in response thereto, initiating the supplying of a flow of argon gas to the chamber to purge air therefrom. Further, the method includes detecting the entry of a fuel rod in the welding chamber and, in response thereto, terminating the supplying of the flow of argon gas to the chamber and initiating the supplying of a flow of helium gas to the chamber to purge argon gas therefrom and displace the argon gas in the chamber. Also, the method includes detecting the withdrawal of the fuel rod from the welding chamber and, in response thereto, terminating the supplying of the flow of helium gas to the chamber and initiating the supplying of argon to the chamber to purge the air therefrom. The method also includes detecting the initiation of a weld cycle and, in response thereto, momentarily supplying a flow of argon gas to the welding electrode tip for initiating the welding arc. (Author)

Multiple responses optimization in the development of a headspace gas chromatography method for the determination of residual solvents in pharmaceuticals

Directory of Open Access Journals (Sweden)

Carla M. Teglia

2015-10-01

Full Text Available An efficient generic static headspace gas chromatography (HSGC method was developed, optimized and validated for the routine determination of several residual solvents (RS in drug substance, using a strategy with two sets of calibration. Dimethylsulfoxide (DMSO was selected as the sample diluent and internal standards were used to minimize signal variations due to the preparative step. A gas chromatograph from Agilent Model 6890 equipped with flame ionization detector (FID and a DB-624 (30 m×0.53 mm i.d., 3.00 µm film thickness column was used. The inlet split ratio was 5:1. The influencing factors in the chromatographic separation of the analytes were determined through a fractional factorial experimental design. Significant variables: the initial temperature (IT, the final temperature (FT of the oven and the carrier gas flow rate (F were optimized using a central composite design. Response transformation and desirability function were applied to find out the optimal combination of the chromatographic variables to achieve an adequate resolution of the analytes and short analysis time. These conditions were 30 °C for IT, 158 °C for FT and 1.90 mL/min for F. The method was proven to be accurate, linear in a wide range and very sensitive for the analyzed solvents through a comprehensive validation according to the ICH guidelines. Keywords: Headspace gas chromatography, Residual solvents, Pharmaceuticals, Surface response methodology, Desirability function

A mutation in the Arabidopsis HYL1 gene encoding a dsRNA binding protein affects responses to abscisic acid, auxin, and cytokinin

Science.gov (United States)

Lu, C.; Fedoroff, N.

2000-01-01

Both physiological and genetic evidence indicate interconnections among plant responses to different hormones. We describe a pleiotropic recessive Arabidopsis transposon insertion mutation, designated hyponastic leaves (hyl1), that alters the plant's responses to several hormones. The mutant is characterized by shorter stature, delayed flowering, leaf hyponasty, reduced fertility, decreased rate of root growth, and an altered root gravitropic response. It also exhibits less sensitivity to auxin and cytokinin and hypersensitivity to abscisic acid (ABA). The auxin transport inhibitor 2,3,5-triiodobenzoic acid normalizes the mutant phenotype somewhat, whereas another auxin transport inhibitor, N-(1-naph-thyl)phthalamic acid, exacerbates the phenotype. The gene, designated HYL1, encodes a 419-amino acid protein that contains two double-stranded RNA (dsRNA) binding motifs, a nuclear localization motif, and a C-terminal repeat structure suggestive of a protein-protein interaction domain. We present evidence that the HYL1 gene is ABA-regulated and encodes a nuclear dsRNA binding protein. We hypothesize that the HYL1 protein is a regulatory protein functioning at the transcriptional or post-transcriptional level.

De-linking oil and gas; The cost of Gulf gas; Middle East gas must look to Europe

International Nuclear Information System (INIS)

Aissaoui, Ali; Jensen, Jim; Stern, Jonathan

1994-01-01

This item consists of letters in response to an article by Robert Mabro on the prospects for gas in North Africa and the Middle East. The first letter is concerned with the issue of de-linking oil and gas. It is argued that the introduction of an ecotax, far from its creators' intentions, may deter investment in the natural gas industry to the benefit of coal and oil producers, rather than promoting gas as the fuel which best protects the environment. The second writer points out the Middle East's geographical disadvantage in aiming to supply natural gas to Europe. While reserves are ample, they are also readily available closer to European consumers, and without extra transportation costs. Markets nearby are either already functioning or, in areas such as India or Pakistan, prohibitively expensive in terms of pipeline construction or other technology. The last author also argues for investment in large-scale pipeline projects in order to use the Middle Eastern gas reserves, but stresses the need for political and security problems to be addressed at the same time. (UK)

Critical consideration on the relationship between auxin transport and calcium transients in gravity perception of Arabidopsis seedlings

Science.gov (United States)

Toyota, Masatsugu; Furuichi, Takuya; Tatsumi, Hitoshi

2008-01-01

Plants regulate their growth and morphogenesis in response to gravity field, known as gravitropism. In the early process of gravitropism, changes in the gravity vector (gravistimulation) are transduced into certain intracellular signals, termed gravity perception. The plant hormone auxin is not only a crucial factor to represent gravitropism but also a potential signaling molecule for gravity perception. Another strong candidate for the signaling molecule is calcium ion of which cytoplasmic concentration ([Ca2+]c) is known to increase in response to gravistimulation. However, relationship between these two factors, say which is in the first place, has been controversial. This issue is addressed here mainly based on recent progress including our latest studies. Gravistimulation by turning plants 180° induced a two-peaked [Ca2+]c-increase lasting for several minutes in Arabidopsis seedlings expressing apoaequorin; only the second peak was sensitive to the gravistimulation. Peak amplitudes of the [Ca2+]c-increase were attenuated by the 10 µM auxin transport inhibitor (TIBA) and vesicle trafficking inhibitor (BFA), whereas the onset time and rate of rise of the second peak were not significantly altered. This result indicates that polar auxin transport is not involved in the initial phase of the second [Ca2+]c-increase. It is likely that the gravi-induced [Ca2+]c-increase constitutes an upstream event of the auxin transport, but may positively be modulated by auxin since its peak amplitude is attenuated by the inhibition of auxin transport. PMID:19513245

Quick response to growth opportunities makes a winner of Piedmont Natural Gas

Energy Technology Data Exchange (ETDEWEB)

1981-02-01

Diversification became a necessity to Piedmont Natural Gas Co. as it increasingly faced curtailments and restrictions on supplies from its single energy source, Transcontinental Gas Pipeline Corp. Passage of the Natural Gas Policy Act of 1978 marked the beginning of a turnaround in Piedmont's sharply curtailed gas supplies, keeping Piedmont totally involved in both conventional marketing and construction and expansion into diversified operations. Its diversifications include (1) a program of energy-saving conservation services, (2) formation of a propane gas division, and (3) distribution of fuel oil, all of which helped Piedmont become a full-service energy-distribution system.

Sensitivity analysis and economic optimization studies of inverted five-spot gas cycling in gas condensate reservoir

OpenAIRE

Shams Bilal; Yao Jun; Zhang Kai; Zhang Lei

2017-01-01

Gas condensate reservoirs usually exhibit complex flow behaviors because of propagation response of pressure drop from the wellbore into the reservoir. When reservoir pressure drops below the dew point in two phase flow of gas and condensate, the accumulation of large condensate amount occurs in the gas condensate reservoirs. Usually, the saturation of condensate accumulation in volumetric gas condensate reservoirs is lower than the critical condensate saturation that causes trapping of large...

Effect of the Detector Width and Gas Pressure on the Frequency Response of a Micromachined Thermal Accelerometer

Directory of Open Access Journals (Sweden)

Johann Courteaud

2011-05-01

Full Text Available In the present work, the design and the environmental conditions of a micromachined thermal accelerometer, based on convection effect, are discussed and studied in order to understand the behavior of the frequency response evolution of the sensor. It has been theoretically and experimentally studied with different detector widths, pressure and gas nature. Although this type of sensor has already been intensively examined, little information concerning the frequency response modeling is currently available and very few experimental results about the frequency response are reported in the literature. In some particular conditions, our measurements show a cut-off frequency at −3 dB greater than 200 Hz. By using simple cylindrical and planar models of the thermal accelerometer and an equivalent electrical circuit, a good agreement with the experimental results has been demonstrated.

Phosphorene as a Superior Gas Sensor: Selective Adsorption and Distinct I-V Response.

Science.gov (United States)

Kou, Liangzhi; Frauenheim, Thomas; Chen, Changfeng

2014-08-07

Recent reports on the fabrication of phosphorene, that is, mono- or few-layer black phosphorus, have raised exciting prospects of an outstanding two-dimensional (2D) material that exhibits excellent properties for nanodevice applications. Here, we study by first-principles calculations the adsorption of CO, CO2, NH3, NO, and NO2 gas molecules on a monolayer phosphorene. Our results predict superior sensing performance of phosphorene that rivals or even surpasses that of other 2D materials such as graphene and MoS2. We determine the optimal adsorption positions of these molecules on the phosphorene and identify molecular doping, that is, charge transfer between the molecules and phosphorene, as the driving mechanism for the high adsorption strength. We further calculated the current-voltage (I-V) relation using the nonequilibrium Green's function (NEGF) formalism. The transport features show large (1-2 orders of magnitude) anisotropy along different (armchair or zigzag) directions, which is consistent with the anisotropic electronic band structure of phosphorene. Remarkably, the I-V relation exhibits distinct responses with a marked change of the I-V relation along either the armchair or the zigzag directions depending on the type of molecules. Such selectivity and sensitivity to adsorption makes phosphorene a superior gas sensor that promises wide-ranging applications.

Gas allocation plans based on failures scenarios: PETROBRAS-Gas and Power Sector

Energy Technology Data Exchange (ETDEWEB)

Faertes, Denise; Vieira, Flavia; Saker, Leonardo; Heil, Luciana [PETROBRAS, Rio de Janeiro, RJ (Brazil); Galvao, Joao [DNV, Rio de Janeiro, RJ (Brazil)

2009-07-01

The purpose of this paper is to present gas allocation plans developed for PETROBRAS Gas and Power Sector, considering failure to supply scenarios that could occur along gas supply network. Those scenarios, as well as the associated contingency plans, were identified and validated by an experienced team, composed by engineers and operators from different PETROBRAS sectors. The key issue of concern was the anticipation of possible undesired scenarios that could imply on contract shortfalls, the evaluation of possible maneuvers, taking into account best gas delivery allocation. Different software were used for the simulation of best gas supply allocation and for the verification of delivery pressure and conditions for final consumers. The ability of being capable of dealing with undesired or crisis scenarios, based on suitable anticipation levels, is, nowadays, a highly valuable attribute to be presented by competitive corporations, for best crisis management and prompt recovery response. Those plans are being used by Gas and Power Gas Operation Control Centre and as an input for reliability modeling of gas supply chain. (author)

Geriatric Anxiety Scale: item response theory analysis, differential item functioning, and creation of a ten-item short form (GAS-10).

Science.gov (United States)

Mueller, Anne E; Segal, Daniel L; Gavett, Brandon; Marty, Meghan A; Yochim, Brian; June, Andrea; Coolidge, Frederick L

2015-07-01

The Geriatric Anxiety Scale (GAS; Segal et al. (Segal, D. L., June, A., Payne, M., Coolidge, F. L. and Yochim, B. (2010). Journal of Anxiety Disorders, 24, 709-714. doi:10.1016/j.janxdis.2010.05.002) is a self-report measure of anxiety that was designed to address unique issues associated with anxiety assessment in older adults. This study is the first to use item response theory (IRT) to examine the psychometric properties of a measure of anxiety in older adults. A large sample of older adults (n = 581; mean age = 72.32 years, SD = 7.64 years, range = 60 to 96 years; 64% women; 88% European American) completed the GAS. IRT properties were examined. The presence of differential item functioning (DIF) or measurement bias by age and sex was assessed, and a ten-item short form of the GAS (called the GAS-10) was created. All GAS items had discrimination parameters of 1.07 or greater. Items from the somatic subscale tended to have lower discrimination parameters than items on the cognitive or affective subscales. Two items were flagged for DIF, but the impact of the DIF was negligible. Women scored significantly higher than men on the GAS and its subscales. Participants in the young-old group (60 to 79 years old) scored significantly higher on the cognitive subscale than participants in the old-old group (80 years old and older). Results from the IRT analyses indicated that the GAS and GAS-10 have strong psychometric properties among older adults. We conclude by discussing implications and future research directions.

Landfill gas: planning and regulation

International Nuclear Information System (INIS)

Nealon, T.

1991-01-01

There is no legislation in the UK that relates directly to landfill gas. However, various pieces of legislation do exist which control all aspects of landfill and therefore, indirectly, landfill gas. This legislation includes Planning Acts, The Control of Pollution Act, Health and Safety at Work Acts, and Public Health Acts, and affects landfill gas throughout the life of the site - from planning stage to long after the last load has been deposited and restoration has been carried out. Responsibility for ensuring compliance with these various Acts lies with a variety of Authorities, including Plannning Authorities, Waste Disposal Authorities, and Environmental Health Authorities. Responsibility for actual compliance with the Acts lies with the operator, for active sites, and the landowner in the case of closed sites. (author)

Gas Sensing Performance of Pure and Modified BST Thick Film Resistor

Directory of Open Access Journals (Sweden)

G. H. JAIN

2008-04-01

Full Text Available Barium Strontium Titanate (BST-(Ba0.87Sr0.13TiO3 ceramic powder was prepared by mechanochemical process. The thick films of different thicknesses of BST were prepared by screen-printing technique and gas-sensing performance of these films was tested for various gases. The films showed highest response and selectivity to ammonia gas. The pure BST film was surface modified by surfactant CrO3 by using dipping technique. The surface modified film suppresses the response to ammonia and enhances to H2S gas. The surface modification of films changes the adsorption-desorption relationship with the target gas and shifts its selectivity. The gas response, selectivity, response and recovery time of the pure and modified films were measured and presented.

Owners responsibility of refrigeration equipment according F-Gas-regulation 'EC 842/2006' and answers; Betreiberpflichten nach 'F-Gas-Verordnung' EG 842/2006 und Antworten darauf

Energy Technology Data Exchange (ETDEWEB)

Beermann, Karsten [IKKE gGmbH, Duisburg (Germany)

2012-08-15

The results of the F-Gas-regulation EC 842/2006 are some responsibilities for owners of refrigeration equipment. To fulfill these duties exist e-learning training modules and different tools which are the result of a European LEONARDO- project. Particularly the awareness of the equipment owner and the certified person (refrigeration technician) according the regulation will be the main background of a safe handling of refrigerants for an effective environmental protection. Interested persons and companies will find helpful information to learn good practice. (orig.)

Multi-annual forward estimate - gas 2017

International Nuclear Information System (INIS)

2017-01-01

GRDF, GRTgaz, SPEGNN and TIGF gas transport and distribution operators have the responsibility to publish a reference document about the multi-annual forward estimate of gas consumption evolution and renewable gas production. This document is the second joint forecast report published by the 4 French gas operators. It presents, first, the situation, hypotheses, analysis and perspectives of the 4 main sectoral gas markets (residential, tertiary, industrial, mobility), then, the centralized power generation and cogeneration, next, the production of renewable gas (different sectors, hypotheses, analysis and perspectives), and finally, a multi-sectorial vision according to 3 different scenarios

Multi-annual forward estimate - gas 2016

International Nuclear Information System (INIS)

2016-01-01

GRDF, GRTgaz, SPEGNN and TIGF gas transport and distribution operators have the responsibility to publish a reference document about the multi-annual forward estimate of gas consumption evolution and renewable gas production. This document is the first joint forecast report published by the 4 French gas operators. It presents, first, the situation, hypotheses, analysis and perspectives of the 4 main sectoral gas markets (residential, tertiary, industrial, mobility), then, the centralized power generation and cogeneration, next, the production of renewable gas (different sectors, hypotheses, analysis and perspectives), and finally, a multi-sectorial vision according to 3 different scenarios

Gas. The Energy of Possibility

International Nuclear Information System (INIS)

2017-01-01

GRTgaz launches a campaign to introduce the general public to all the gas energy industry's advanced solutions for the future of energy. Gas takes on new forms through innovative and ambitious solutions that offer concrete applications in territories: producing biomethane from agricultural, industrial or domestic waste, transforming excess renewable electricity into storable renewable gas, using gas and biomethane for cleaner land transport and, in liquid form, cleaner sea transport. In support of this energy source, France can rely on its discreet and robust gas infrastructure to promote the growing dynamic and offer a response to major challenges, such as air quality, waste management and renewable energy storage

A Novel CO2-Responsive Viscoelastic Amphiphilic Surfactant Fluid for Fracking in Enhanced Oil/Gas Recovery

Science.gov (United States)

Zhong, L.; Wu, X.; Dai, C.

2017-12-01

Over the past decade, the rapid rise of unconventional shale gas and tight sandstone oil development through horizontal drilling and high volume hydraulic fracturing has expanded the extraction of hydrocarbon resources. Hydraulic fracturing fluids play very important roles in enhanced oil/gas recovery. However, damage to the reservoir rock and environmental contamination caused by hydraulic fracturing flowback fluids has raised serious concerns. The development of reservoir rock friendly and environmental benign fracturing fluids is in immediate demand. Studies to improve properties of hydraulic fracturing fluids have found that viscoelastic surfactant (VES) fracturing fluid can increase the productivity of gas/oil and be efficiently extracted after fracturing. Compared to conventional polymer fracturing fluid, VES fracturing fluid has many advantages, such as few components, easy preparation, good proppant transport capacity, low damage to cracks and formations, and environment friendly. In this work, we are developing a novel CO2-responsive VES fracking fluid that can readily be reused. This fluid has a gelling-breaking process that can be easily controlled by the presence of CO2 and its pressure. We synthesized erucamidopropyl dimethylamine (EA) as a thickening agent for hydraulic fracturing fluid. The influence of temperature, presence of CO2 and pressure on the viscoelastic behavior of this fluid was then investigated through rheological measurements. The fracturing fluid performance and recycle property were lastly studied using core flooding tests. We expect this fluid finds applications not only in enhanced oil/gas recovery, but also in areas such as controlling groundwater pollution and microfluidics.

Influence of myocardial oxygen demand on the coronary vascular response to arterial blood gas changes in humans.

Science.gov (United States)

Vermeulen, Tyler Dennis; Boulet, Lindsey M; Stembridge, Mike; Williams, Alexandra Mackenzie; Anholm, James D; Subedi, Prajan; Gasho, Chris; Ainslie, Philip N; Feigl, Eric O; Foster, Glen Edward

2018-03-30

It remains unclear if the human coronary vasculature is inherently sensitive to changes in arterial PO 2 and PCO 2 or if coronary vascular responses are the result of concomitant increases in myocardial O 2 consumption/demand (MVO 2 ). We hypothesized that the coronary vascular response to PO 2 and PCO 2 would be attenuated in healthy men when MVO 2 was attenuated with β 1 -adrenergic receptor blockade. Healthy men (n=11; age: 25 {plus minus} 1 years) received intravenous esmolol (β 1 -adrenergic receptor antagonist) or volume-matched saline in a double-blind, randomized, crossover study, and were exposed to poikilocapnic hypoxia, isocapnic hypoxia, and hypercapnic hypoxia. Measurements made at baseline and following 5-min of steady state at each gas manipulation included left anterior descending coronary blood velocity (LAD V ; Doppler echocardiography), heart rate and arterial blood pressure. LAD V values at the end of each hypoxic condition were compared between esmolol and placebo. Rate pressure product (RPP) and left-ventricular mechanical energy (ME LV ) were calculated as indices of MVO 2 . All gas manipulations augmented RPP, ME LV , and LAD V but only RPP and ME LV were attenuated (4-18%) following β 1 -adrenergic receptor blockade (P<0.05). Despite attenuated RPP and MELV responses, β 1 -adrenergic receptor blockade did not attenuate the mean LADV vasodilatory response when compared to placebo during poikilocapnic hypoxia (29.4{plus minus}2.2 vs. 27.3{plus minus}1.6 cm/s) and isocapnic hypoxia (29.5{plus minus}1.5 vs. 30.3{plus minus}2.2 cm/s). Hypercapnic hypoxia elicited a feed-forward coronary dilation that was blocked by β 1 -adrenergic receptor blockade. These results indicate a direct influence of arterial PO 2 on coronary vascular regulation that is independent of MVO 2 .

Corporate renewal in the natural gas industry

International Nuclear Information System (INIS)

Simpson, B.

1994-01-01

The changes occurring at the gas-related operating companies of Nova Corporation of Alberta are reviewed. These companies include Nova Gas Transmission, Alberta's major gas pipeline company, which moved 3.8 trillion ft 3 of gas in 1993; Nova Gas Services, a provider of gas management services to customers in Canada, USA, and Mexico; and Novacorp International, a joint venture investor in gas pipeline developments and consulting. The changes were made in response to increased competition in the gas transport industry following the deregulation process that started in the mid-1980s. A strategic direction based on growth rather than cost-cutting was chosen in order to make the Nova companies dominant players in North American gas supply. Nova's confidence in being able to implement such a strategy is based on four factors: abundant supply of gas and high potential for growth in the Western Canada Sedimentary Basin; steadily growing demand for gas; the development of a market-responsive industry; and the emergence of a truly North American market that includes Mexico. Business transformation teams were established with the task of finding out the right business design to meet customer needs and to provide exceptional service. Detailed plans for implementing the transformation are being completed, and a performance measurement system with clear targets has been developed to measure the success of the transformation

Soviet Union: priority development of gas industry forecast

International Nuclear Information System (INIS)

Chernomyrdyn, V.S.

1991-01-01

The development of gas production and utilization in the Soviet Union is outlined, and the substantial contribution of the gas industry in restraining negative processes in the economy during the transition to a market economy is highlighted. The state owned Gazprom concern which is responsible for gas supply, the large ringed Integrated Gas Supply Systems, exports, underground gas storage, potential reserves, and the growth in gas productions are discussed. (UK)

Oil and gas in British Columbia : 10 steps to responsible development

International Nuclear Information System (INIS)

2004-04-01

The British Columbia government has proposed to double production of oil and gas, the burning of which causes global warming. West Coast Environmental Law (WCEL) claims there is a strong divide between British Columbia's plans to expand the production and use of fossil fuels, and the international scientific consensus regarding the negative aspects of global warming. The impacts of oil and gas production negatively affect the health of local citizens, First Nations rights and the environment. Offshore oil and gas development could also threaten fisheries and pollute sensitive marine ecosystems. WCEL criticizes the fact that the British Columbia government has streamlined environmental regulations, has laid off compliance monitoring staff, and has given subsidies to the highly profitable oil and gas industry. WCEL argues that the impact of fossil fuel production must be mitigated to limit the damage to lands and people in British Columbia. The organization has proposed 10 recommendations to the British Columbia government. The recommendations focus on impacts of land-based oil and gas development rather than offshore impacts. WCEL claims that adoption of the 10-point mitigation plan is vital for putting British Columbia on the path toward sustainable development. 43 refs

Productivity improvements in gas distribution

International Nuclear Information System (INIS)

Young, M.R.

1997-01-01

In 1993, the Hilmer Report resulted in the introduction of the National Competition Policy which, in the case of the gas industry, aims to promote gas-on-gas competition where to date it has been excluded. In response, and to prepare for wide gas industry reform, Gas and Fuel formed three fundamentally different core businesses on 1 July 1996 - Energy Retail, Network, and Contestable Services. In one productivity improvement initiative which is believed to be unique, Gas and Fuel appointed three companies as strategic alliance partners for distribution system maintenance. Gas and Fuel can now concentrate on its core role as asset manager which owns and operates the distribution system while procuring all services from what will become non-regulated businesses. This Paper details this initiative and the benefits which have resulted from overall changes and improvements, and outlines the challenges facing Gas and Fuel in the future. (au)

Study the gas sensing properties of boron nitride nanosheets

International Nuclear Information System (INIS)

Sajjad, Muhammad; Feng, Peter

2014-01-01

Graphical abstract: - Highlights: • We synthesized boron nitride nanosheets (BNNSs) on silicon substrate. • We analyzed gas sensing properties of BNNSs-based gas-sensor device. • CH 4 gas is used to measure gas-sensing properties of the device. • Quick response and recovery time of the device is recorded. • BNNSs showed excellent sensitivity to the working gas. - Abstract: In the present communication, we report on the synthesis of boron nitride nanosheets (BNNSs) and study of their gas sensing properties. BNNSs are synthesized by irradiating pyrolytic hexagonal boron nitride (h-BN) target using CO 2 laser pulses. High resolution transmission electron microscopic measurements (HRTEM) revealed 2-dientional honeycomb crystal lattice structure of BNNSs. HRTEM, electron diffraction, XRD and Raman scattering measurements clearly identified h-BN. Gas sensing properties of synthesized BNNSs were analyzed with prototype gas sensor using methane as working gas. A systematic response curve of the sensor is recorded in each cycle of gas “in” and “out”; suggesting excellent sensitivity and high performance of BNNSs-based gas-sensor

Magnesium ferrite nanoparticles: a rapid gas sensor for alcohol

Science.gov (United States)

Godbole, Rhushikesh; Rao, Pratibha; Bhagwat, Sunita

2017-02-01

Highly porous spinel MgFe2O4 nanoparticles with a high specific surface area have been successfully synthesized by a sintering free auto-combustion technique and characterized for their structural and surface morphological properties using XRD, BET, TEM and SEM techniques. Their sensing properties to alcohol vapors viz. ethanol and methanol were investigated. The site occupation of metal ions was investigated by VSM. The as-synthesized sample shows the formation of sponge-like porous material which is necessary for gas adsorption. The gas sensing characteristics were obtained by measuring the gas response as a function of operating temperature, concentration of the gas, and the response-recovery time. The response of magnesium ferrite to ethanol and methanol vapors was compared and it was revealed that magnesium ferrite is more sensitive and selective to ethanol vapor. The sensor operates at a substantially low vapor concentration of about 1 ppm of alcohol vapors, exhibits fantastic response reproducibility, long term reliability and a very fast response and recovery property. Thus the present study explored the possibility of making rapidly responding alcohol vapor sensor based on magnesium ferrite. The sensing mechanism has been discussed in co-relation with magnetic and morphological properties. The role of occupancy of Mg2+ ions in magnesium ferrite on its gas sensing properties has also been studied and is found to influence the response of magnesium ferrite ethanol sensor.

Gas by the turn of the century

Energy Technology Data Exchange (ETDEWEB)

McDonald, S. [Sable Offshore Energy Inc., Halifax, NS (Canada)

1999-07-01

The impact that the Sable Offshore Energy Project will have on the economy of Nova Scotia was discussed with particular focus on the current status of the project and the growth of the offshore industry in eastern Canada. Exploration activity in the area, which has been headed by Mobil Oil Canada and Shell Canada Ltd., has been ongoing for more than three decades. The development plan for the project gained final regulatory approval in 1997. Sable Offshore Energy Inc. is responsible for the development and production of the raw gas from six offshore natural gas fields including Thebaud, Venture, North Triumph, Alma, Glenelg, and South Venture. Combined, these six fields have reserves estimated at 3.5 trillion cubic feet of natural gas to be produced over the next 20 to 25 years. Sable Offshore Energy Inc. will also be responsible for processing the gas and associated liquids to market quality at onshore facilities. Sable Offshore Energy Inc. is an owner operating company representing Mobil Oil Canada, Shell Canada Ltd., Imperial Oil Resources, Nova Scotia Resources, and Mosbacher Operating Ltd. These owner companies are responsible for marketing the natural gas and associated liquids in the Maritimes and elsewhere in North America. The Maritimes and Northeast Pipeline Co. will transport Sable natural gas to markets in Nova Scotia, New Brunswick and New England as early as November 1999.

Gas by the turn of the century

International Nuclear Information System (INIS)

McDonald, S.

1999-01-01

The impact that the Sable Offshore Energy Project will have on the economy of Nova Scotia was discussed with particular focus on the current status of the project and the growth of the offshore industry in eastern Canada. Exploration activity in the area, which has been headed by Mobil Oil Canada and Shell Canada Ltd., has been ongoing for more than three decades. The development plan for the project gained final regulatory approval in 1997. Sable Offshore Energy Inc. is responsible for the development and production of the raw gas from six offshore natural gas fields including Thebaud, Venture, North Triumph, Alma, Glenelg, and South Venture. Combined, these six fields have reserves estimated at 3.5 trillion cubic feet of natural gas to be produced over the next 20 to 25 years. Sable Offshore Energy Inc. will also be responsible for processing the gas and associated liquids to market quality at onshore facilities. Sable Offshore Energy Inc. is an owner operating company representing Mobil Oil Canada , Shell Canada Ltd., Imperial Oil Resources, Nova Scotia Resources, and Mosbacher Operating Ltd. These owner companies are responsible for marketing the natural gas and associated liquids in the Maritimes and elsewhere in North America. The Maritimes and Northeast Pipeline Co. will transport Sable natural gas to markets in Nova Scotia, New Brunswick and New England as early as November 1999

Natural gas: modern application - the environmental question

International Nuclear Information System (INIS)

Suarez, Miriam Liliana Hinostroza; Guerra, Sinclair Mallet-Guy

1999-01-01

Natural gas has been proposed as a transition fuel. The combustion of natural gas emits less CO 2 per unit of energy than the combustion of other fossil fuels. Increased reliance upon natural gas in preference to other fossil fuels would be encouraged to mitigate greenhouse gas releases while more comprehensive responses are devised to provide more time for adaptation to the inevitable climate change. In this context, the article overviews of natural gas and its relation with the environment

The Jarvis gas release incident

International Nuclear Information System (INIS)

Manocha, J.

1992-01-01

On 26 September, 1991, large volumes of natural gas were observed to be leaking from two water wells in the Town of Jarvis. Gas and water were being ejected from a drilled water well, at which a subsequent gas explosion occurred. Measurements of gas concentrations indicated levels far in excess of the lower flammability limit at several locations. Electrical power and natural gas services were cut off, and residents were evacuated. A state of emergency was declared, and gas was found to be flowing from water wells, around building foundations, and through other fractures in the ground. By 27 September the volumes of gas had reduced substantially, and by 30 September all residents had returned to their homes and the state of emergency was cancelled. The emergency response, possible pathways of natural gas into the aquifer, and public relations are discussed. It is felt that the likelihood of a similar incident occurring in the future is high. 11 figs

Asymmetric price responses, market integration and market power: A study of the U.S. natural gas market

International Nuclear Information System (INIS)

Murry, Donald; Zhu, Zhen

2008-01-01

We studied the market performance at selected, representative natural gas trading hubs in the U.S. and documented different price behaviors among various hubs. With NYMEX prices as the competitive benchmark, we found empirically that the spot price responses at some trading hubs were systematically asymmetric, thus demonstrating a market advantage by either buyers or sellers. We further found that the presence of market power was a very plausible explanation for this price behavior at some hubs. (author)

Louisiana waterthrush and benthic macroinvertebrate response to shale gas development

Science.gov (United States)

Wood, Petra; Frantz, Mack W.; Becker, Douglas A.

2016-01-01

Because shale gas development is occurring over large landscapes and consequently is affecting many headwater streams, an understanding of its effects on headwater-stream faunal communities is needed. We examined effects of shale gas development (well pads and associated infrastructure) on Louisiana waterthrush Parkesia motacilla and benthic macroinvertebrate communities in 12 West Virginia headwater streams in 2011. Streams were classed as impacted (n = 6) or unimpacted (n = 6) by shale gas development. We quantified waterthrush demography (nest success, clutch size, number of fledglings, territory density), a waterthrush Habitat Suitability Index, a Rapid Bioassessment Protocol habitat index, and benthic macroinvertebrate metrics including a genus-level stream-quality index for each stream. We compared each benthic metric between impacted and unimpacted streams with a Student's t-test that incorporated adjustments for normalizing data. Impacted streams had lower genus-level stream-quality index scores; lower overall and Ephemeroptera, Plecoptera, and Trichoptera richness; fewer intolerant taxa, more tolerant taxa, and greater density of 0–3-mm individuals (P ≤ 0.10). We then used Pearson correlation to relate waterthrush metrics to benthic metrics across the 12 streams. Territory density (no. of territories/km of stream) was greater on streams with higher genus-level stream-quality index scores; greater density of all taxa and Ephemeroptera, Plecoptera, and Trichoptera taxa; and greater biomass. Clutch size was greater on streams with higher genus-level stream-quality index scores. Nest survival analyses (n = 43 nests) completed with Program MARK suggested minimal influence of benthic metrics compared with nest stage and Habitat Suitability Index score. Although our study spanned only one season, our results suggest that shale gas development affected waterthrush and benthic communities in the headwater streams we studied. Thus, these ecological effects of

Effect of foundation embedment on the seismic response of a high-temperature gas-cooled reactor plant

International Nuclear Information System (INIS)

Lee, T.H.; Thompson, R.W.; Charman, C.M.

1983-01-01

The effects of soil-structure interaction during seismic events upon the dynamic response of a High Temperature Gas-Cooled Reactor plant (HTGR) have been investigated for both surface-founded and embedded basemats. The influence from foundation embedment has been quantitatively assessed through a series of theoretical studies on plants of various sizes. The surface-founded analyses were performed using frequency-independent soil impedance parameters, while the embedded plant analyses utilized finite element models simulated on the FLUSH computer program. The seismic response of the surface-founded plants has been used to establish the standard-site design in-structure response spectra. These analyses were performed by using the linear modal formulation based on conventional soil stiffness and damping values. They serve as reference solutions to which the response data of the corresponding embedded plants are compared. In these comparison studies the responses of embedded plants were generally found to be lower than those of the corresponding surface-founded plants. Additional studies on the surface-founded plants have recently been performed by considering inelastic soil behavior. These inelastic solutions, which treat the soil as an elasto-plastic medium exhibiting hysteretic unloading-reloading characteristics in time, have reduced the response of surface-founded plants. Numerical results are presented in terms of in-structure response spectra along with other pertinent seismic load data at key levels of the plant. Analysis techniques for future studies using viscoelastic halfspace representation and inelastic finite element modeling for soil are also discussed

Response speed of SnO2-based H2S gas sensors with CuO nanoparticles

International Nuclear Information System (INIS)

Chowdhuri, Arijit; Gupta, Vinay; Sreenivas, K.; Kumar, Rajeev; Mozumdar, Subho; Patanjali, P. K.

2004-01-01

CuO nanoparticles on sputtered SnO 2 thin-film surface exhibit a fast response speed (14 s) and recovery time (61 s) for trace level (20 ppm) H 2 S gas detection. The sensitivity of the sensor (S∼2.06x10 3 ) is noted to be high at a low operating temperature of 130 deg. C. CuO nanoparticles on SnO 2 allow effective removal of excess adsorbed oxygen from the uncovered SnO 2 surface due to spillover of hydrogen dissociated from the H 2 S-CuO interaction

Sprayed zinc oxide films: Ultra-violet light-induced reversible surface wettability and platinum-sensitization-assisted improved liquefied petroleum gas response.

Science.gov (United States)

Nakate, Umesh T; Patil, Pramila; Bulakhe, R N; Lokhande, C D; Kale, Sangeeta N; Naushad, Mu; Mane, Rajaram S

2016-10-15

We report the rapid (superhydrophobic to superhydrophilic) transition property and improvement in the liquefied petroleum gas (LPG) sensing response of zinc oxide (ZnO) nanorods (NRs) on UV-irradiation and platinum (Pt) surface sensitization, respectively. The morphological evolution of ZnO NRs is evidenced from the field emission scanning electron microscope and atomic force microscope digital images and for the structural elucidation X-ray diffraction pattern is used. Elemental survey mapping is obtained from energy dispersive X-ray analysis spectrum. The optical properties have been studied by UV-Visible and photoluminescence spectroscopy measurements. The rapid (120sec) conversion of superhydrophobic (154°) ZnO NRs film to superhydrophilic (7°) is obtained under UV light illumination and the superhydrophobicity is regained by storing sample in dark. The mechanism for switching wettability behavior of ZnO NRs has thoroughly been discussed. In second phase, Pt-sensitized ZnO NRs film has demonstrated considerable gas sensitivity at 260ppm concentration of LPG. At 623K operating temperature, the maximum LPG response of 58% and the response time of 49sec for 1040ppm LPG concentration of Pt- sensitized ZnO NRs film are obtained. This higher LPG response of Pt-sensitized ZnO NRs film over pristine is primarily due to electronic effect and catalytic effect (spill-over effect) caused by an additional of Pt on ZnO NRs film surface. Copyright © 2016 Elsevier Inc. All rights reserved.

Corporate Spheres of Responsibility: Architects, Cowboys, and Eco-Warriors in Myanmar’s Oil & Gas Industry

Directory of Open Access Journals (Sweden)

Hillary Strasser

2017-04-01

Full Text Available Myanmar's recently opened economy is flush with incoming investment and activity. World leaders advocate that all businesses entering the country must operate in a "socially responsible manner." However, the history of corporate social responsibility (CSR in Myanmar is undefined, contradictory, and complex. Thus, to get a handle around what it means to be “responsible,” this paper investigates the collective way in which actors in the petroleum industry in Myanmar enact CSR from 1990 to 2014. The oil and gas (O&G industry is the most lucrative, and arguably powerful, national sector. The practice and philosophy of CSR, which originated in this industry, is now proclaimed to be the starting point for this newly charted course of responsible business in Myanmar. Yet, activists and critics maintain that CSR is an insincere PR measure of profit maximization whereby companies can conduct business as normal. I argue that CSR in the Myanmar petroleum industry is influenced by more complex factors than profit maximization or image management. CSR initiatives are sculpted by (1 the geography of petroleum extraction, (2 corporate philosophies and company national origins, and (3 type of company operations. The petroleum industry’s CSR activities to date, in terms of geographic span and development targets, all fit into a spectrum of assumed spheres of corporate responsibility that have been forged by the corporate ‘architects’ and tempered by geographic and global forces.

European gas market developments. Opportunities and threats

International Nuclear Information System (INIS)

Van Oostvoorn, F.

1998-09-01

The paper is based on two studies conducted by ECN, namely a study entitled 'An analysis of the West-European gas market: a company approach' and another entitled 'Developments of gas markets across Europe' to be published in November 1998. The paper addresses the past driving factors responsible for the increasing share of gas in the EU energy demand. Furthermore it very briefly discusses the rising dependency of the European Union (EU) on gas imports from non-EU sources such as Russia and the expected gas-to-gas competition in a large number of EU countries in the next decades. 25 refs

Effects of Textural Properties on the Response of a SnO2-Based Gas Sensor for the Detection of Chemical Warfare Agents

Directory of Open Access Journals (Sweden)

Duk Dong Lee

2011-07-01

Full Text Available The sensing behavior of SnO2-based thick film gas sensors in a flow system in the presence of a very low concentration (ppb level of chemical agent simulants such as acetonitrile, dipropylene glycol methyl ether (DPGME, dimethyl methylphosphonate (DMMP, and dichloromethane (DCM was investigated. Commercial SnO2 [SnO2(C] and nano-SnO2 prepared by the precipitation method [SnO2(P] were used to prepare the SnO2 sensor in this study. In the case of DCM and acetonitrile, the SnO2(P sensor showed higher sensor response as compared with the SnO2(C sensors. In the case of DMMP and DPGME, however, the SnO2(C sensor showed higher responses than those of the SnO2(P sensors. In particular, the response of the SnO2(P sensor increased as the calcination temperature increased from 400 °C to 800 °C. These results can be explained by the fact that the response of the SnO2-based gas sensor depends on the textural properties of tin oxide and the molecular size of the chemical agent simulant in the detection of the simulant gases (0.1–0.5 ppm.

Electrodes for Semiconductor Gas Sensors

Science.gov (United States)

Lee, Sung Pil

2017-01-01

The electrodes of semiconductor gas sensors are important in characterizing sensors based on their sensitivity, selectivity, reversibility, response time, and long-term stability. The types and materials of electrodes used for semiconductor gas sensors are analyzed. In addition, the effect of interfacial zones and surface states of electrode–semiconductor interfaces on their characteristics is studied. This study describes that the gas interaction mechanism of the electrode–semiconductor interfaces should take into account the interfacial zone, surface states, image force, and tunneling effect. PMID:28346349

Geomechanical response of permafrost-associated hydrate deposits to depressurization-induced gas production

Science.gov (United States)

Rutqvist, J.; Moridis, G.J.; Grover, T.; Collett, T.

2009-01-01

In this simulation study, we analyzed the geomechanical response during depressurization production from two known hydrate-bearing permafrost deposits: the Mallik (Northwest Territories, Canada) deposit and Mount Elbert (Alaska, USA) deposit. Gas was produced from these deposits at constant pressure using horizontal wells placed at the top of a hydrate layer (HL), located at a depth of about 900??m at the Mallik site and 600??m at the Mount Elbert site. The simulation results show that general thermodynamic and geomechanical responses are similar for the two sites, but with substantially higher production and more intensive geomechanical responses at the deeper Mallik deposit. The depressurization-induced dissociation begins at the well bore and then spreads laterally, mainly along the top of the HL. The depressurization results in an increased shear stress within the body of the receding hydrate and causes a vertical compaction of the reservoir. However, its effects are partially mitigated by the relatively stiff permafrost overburden, and compaction of the HL is limited to less than 0.4%. The increased shear stress may lead to shear failure in the hydrate-free zone bounded by the HL overburden and the downward-receding upper dissociation interface. This zone undergoes complete hydrate dissociation, and the cohesive strength of the sediment is low. We determined that the likelihood of shear failure depends on the initial stress state as well as on the geomechanical properties of the reservoir. The Poisson's ratio of the hydrate-bearing formation is a particularly important parameter that determines whether the evolution of the reservoir stresses will increase or decrease the likelihood of shear failure.

A functional TOC complex contributes to gravity signal transduction in Arabidopsis.

Science.gov (United States)

Strohm, Allison K; Barrett-Wilt, Greg A; Masson, Patrick H

2014-01-01

Although plastid sedimentation has long been recognized as important for a plant's perception of gravity, it was recently shown that plastids play an additional function in gravitropism. The Translocon at the Outer envelope membrane of Chloroplasts (TOC) complex transports nuclear-encoded proteins into plastids, and a receptor of this complex, Toc132, was previously hypothesized to contribute to gravitropism either by directly functioning as a gravity signal transducer or by indirectly mediating the plastid localization of a gravity signal transducer. Here we show that mutations in multiple genes encoding TOC complex components affect gravitropism in a genetically sensitized background and that the cytoplasmic acidic domain of Toc132 is not required for its involvement in this process. Furthermore, mutations in TOC132 enhance the gravitropic defect of a mutant whose amyloplasts lack starch. Finally, we show that the levels of several nuclear-encoded root proteins are altered in toc132 mutants. These data suggest that the TOC complex indirectly mediates gravity signal transduction in Arabidopsis and support the idea that plastids are involved in gravitropism not only through their ability to sediment but also as part of the signal transduction mechanism.

Response of small pitot tubes in gas-liquid flows

International Nuclear Information System (INIS)

Davis, M.R.

1980-01-01

The pressure rise experienced by a pitot tube immersed in a bubbly gas-liquid mixture flow exceeds that predicted by homogeneous flow analysis under conditions where the pitot is smaller than the mean bubble size. A systematic dependence of the deviation from homogeneous flow analysis exists, depending upon the mixture void fraction. A maximum effect is observed at a void fraction of 0.60, where the pressure rise was found to be 1.73 times the predicted stagnation pressure rise or 0.87 of the mixture momentum flux density. The magnitude of these effects is comparable with similar effects reported elsewhere for gas/solid mixture flow due to relative motion between phases in the vicinity of the sensing probe tip. (orig.)

Gas exchange and growth responses to nutrient enrichment in invasive Glyceria maxima and native New Zealand Carex species

DEFF Research Database (Denmark)

Sorrell, Brian Keith; Brix, Hans; Fitridge, Isla

2012-01-01

We compared photosynthetic gas exchange, the photosynthesis-leaf nitrogen (N) relationship, and growth response to nutrient enrichment in the invasive wetland grass Glyceria maxima (Hartman) Holmburg with two native New Zealand Carex sedges (C. virgata Boott and C. secta Boott), to explore...... the ecophysiological traits contributing to invasive behaviour. The photosynthesis-nitrogen relationship was uniform across all three species, and the maximum light-saturated rate of photosynthesis expressed on a leaf area basis (Amaxa) did not differ significantly between species. However, specific leaf area (SLA...... the sedges, but correlations between leaf N, gas exchange parameters (Amaxa, Amaxm, Rd and gs) and RGR were all highly significant in G. maxima, whereas they were weak or absent in the sedges. Allocation of biomass (root:shoot ratio, leaf mass ratio, root mass ratio), plant N and P content, and allocation...

Natural gas industry in Bulgaria

International Nuclear Information System (INIS)

Mashkin, L.

1994-01-01

An overview of the Bulgarian natural gas industry is presented. The starting point was the discovery of the indigenous Chiren gas-field in 1967. The first agreement with the ex-USSR for supply of natural gas and construction of main pipelines was signed in 1968. The state gas company BULGARGAZ is responsible for transportation, storage, distribution, processing and marketing of the gas to over 150 industrial companies in the country, as well as for the transportation services to gas importers in neighboring Turkey. The GAZSTROJMONTAZH company accomplish the construction of the local and transit pipelines to Turkey and Greece, as well as of some objects in Iran, Syria, Ukraine and Germany. In the past 20 years, 87890 million m 3 natural gas from Russia are supplied and 846 million m 3 - from domestic sources. The share of natural gas in the overall energy balance is 13.6% for 1992. The restructuring and further development of gas industry require to take into account some factors as: security in supply; investments for technical assurance; pricing policy for natural gas; development of private business. Some administrative problems are also mentioned. 2 tabs., 1 fig

Finland's leading natural gas company

International Nuclear Information System (INIS)

Anon.

2000-01-01

The ownership structure of Finland's leading natural gas company, Gasum, changed fundamentally in 1999, and the company is now no longer a subsidiary of Fortum Corporation. 'Our new strong and broad ownership base will enable us to develop the natural gas business and pipeline network in Finland in response to the requirements of our Finnish customers', says Antero Jaennes, Gasum's Chairman and CEO, who stresses that Gasum is committed to remaining the leading developer of the Finnish natural gas market and the number-one gas supplier. Natural gas usage in Finland in 1999 totalled 3.9 billion m 3 (38.7 TWh), unchanged from 1998. Natural gas accounted for 11% of Finland's total primary energy need, as it did in 1998. The proportion of natural gas used in district heating rose by 2% to 36%, and moved down 2% in power generation to 10%. Industry's use of natural gas fell 1% to 17%. 75% of natural gas was used in combined heat and power (CHP) generation in industry and district heating. In 2000, Gasum expects to sell 4 billion m 3 of natural gas (40 TWh)

Research on Distributed Gas Detection Based on Hollow-core Photonic Crystal Fiber

Directory of Open Access Journals (Sweden)

Gui XIN

2014-07-01

Full Text Available We have demonstrated a distributed gas detection system by using hollow-core photonic crystal fiber (HC-PCF as a gas chamber. The HC-PCF gas chamber has several lateral micro- channels fabricated by the femtosecond laser. The HC-PCF is connected to the single mode fiber by thermal splicing, and gas can diffuse in hollow-core of PCF via micro-channels. Compared to the traditional gas chamber, the HC-PCF gas chamber has relatively simpler construction and quite stability. According to experiment results, the system response time of 15 s has been achieved for a 5 cm HC-PCF which has ten channels with 4mm channel distance. It would construct long sensing length fiber gas sensor that the side holes and the splicer have introduced very little loss. Thus make it possible to achieve highly sensitive sensing system without influencing the response time. By using self-reference demodulation algorithm and space division multiplexing technique, distributed gas detection system with fast response was achieved.

Photosynthesis Decrease and Stomatal Control of Gas Exchange in Abies alba Mill. in Response to Vapor Pressure Difference.

Science.gov (United States)

Guehl, J M; Aussenac, G

1987-02-01

The responses of steady state CO(2) assimilation rate (A), transpiration rate (E), and stomatal conductance (g(s)) to changes in leaf-to-air vapor pressure difference (DeltaW) were examined on different dates in shoots from Abies alba trees growing outside. In Ecouves, a provenance representative of wet oceanic conditions in Northern France, both A and g(s) decreased when DeltaW was increased from 4.6 to 14.5 Pa KPa(-1). In Nebias, which represented the dry end of the natural range of A. alba in southern France, A and g(s) decreased only after reaching peak levels at 9.0 and 7.0 Pa KPa(-1), respectively. The representation of the data in assimilation rate (A) versus intercellular CO(2) partial pressure (C(i)) graphs allowed us to determine how stomata and mesophyll photosynthesis interacted when DeltaW was increased. Changes in A were primarily due to alterations in mesophyll photosynthesis. At high DeltaW, and especially in Ecouves when soil water deficit prevailed, A declined, while C(i) remained approximately constant, which may be interpreted as an adjustment of g(s) to changes in mesophyll photosynthesis. Such a stomatal control of gas exchange appeared as an alternative to the classical feedforward interpretation of E versus DeltaW responses with a peak rate of E. The gas exchange response to DeltaW was also characterized by considerable deviations from the optimization theory of IR Cowan and GD Farquhar (1977 Symp Soc Exp Biol 31: 471-505).

Deregulation of natural gas in Georgia

International Nuclear Information System (INIS)

Wise, S.

2002-01-01

The Natural Gas Competition and Deregulation Act of 1997 in Georgia is discussed. New legislation passed the Natural Gas Consumer Relief Act in 2002 legislative session to provide additional protection and increase competition. This Act and its impacts are discussed in detail. Additional commission responsibilities are summarized. (R.P.)

Metering; Accurate, fast response the key. [In gas distribution companies

Energy Technology Data Exchange (ETDEWEB)

Johnson, J. (Atlanta Gas Light Co. of Georgia (US))

1990-06-01

Automated meter reading systems are quickly becoming a necessity for local gas distribution companies in the United States, especially as end-users involve themselves in the energy business. With open-access transportation available from the pipelines, balancing on the various systems has become critical, not only from a contractual standpoint but for billing purposes as well. Improved accuracy and decreased time period for accessing gas consumption data are the major motivators in the decision to install a remote data acquisition system. The Metretek system which is one source of this new technology described. (author).

The gas sensing characteristics of bismuth chromate material. [BiCrO

Energy Technology Data Exchange (ETDEWEB)

Yifan, Hu; Rongchang, Yin [Dept. of Physics, Huazhong Univ. of Science and Tech., Wuhan, HB (China)

1990-11-16

A thick film gas sensor made from porous bismuthchromate is presented. The sensor operates by the bulk conductivity of bismuth chromate semiconductor catalyst. When a reducing gas is present, the catalyst is reduced and produces highly mobile oxygen vacancies, which have a direct effect on the carrier density throughout the sample. In the air, on the other hand, this process is completely reversible. Therefore the sensor response to a reducing gas is indicated by an increase in the conductance of the sensor. It is found that only exposed to alcohol vapour the sensor shows a high response, while exposure of the sensor to ketone vapour produces comparatively little response and to other vapour like alkenes, alkanes, hydrogen, and carbon monoxide basically no response. Other advantages include long term stability, lack of sensitivity to water vapour, a fast response, and a lower operating temperature than the gas sensors now in use. (orig.).

Strategies implemented by the textile industry in response to natural-gas curtailments

Energy Technology Data Exchange (ETDEWEB)

Schreibeis, R.L.

1980-01-01

An examination is made of specific activities undertaken by textile firms in North and South Carolina and Georgia to insulate themselves against production losses resulting from natural gas curtailments. Results of the research effort focusing on investigating patterns or trends of precautionary activities undertaken by the textile industry in response to fuel interruptions are presented. Chapter II delineates the scope of the project, research design, and nature of the textile industry. One hundred candidate firms for detailed study were identified and 34 discussed their alternate fuel strategies. Information obtained was analyzed by means of two statistical analysis techniques. Methods employed and results are described in Chapter III. Overall results are presented in Chapter IV. Variations in the strategies implemented by various concerns were accounted for in terms of geographic location, plant size, plant type, and the duration and extent of curtailment impacts. Ranges of expenditures for short- and long-term strategies are identified.

Gas-phase photocatalysis in μ-reactors

DEFF Research Database (Denmark)

Vesborg, Peter Christian Kjærgaard; Olsen, Jakob Lind; Henriksen, Toke Riishøj

2010-01-01

Gas-phase photocatalysis experiments may benefit from the high sensitivity and good time response in product detection offered by μ-reactors. We demonstrate this by carrying out CO oxidation and methanol oxidation over commercial TiO2 photocatalysts in our recently developed high-sensitivity reac......Gas-phase photocatalysis experiments may benefit from the high sensitivity and good time response in product detection offered by μ-reactors. We demonstrate this by carrying out CO oxidation and methanol oxidation over commercial TiO2 photocatalysts in our recently developed high...

EPA Participates in Energy Roundtable with States, Tribes, Businesses and Environmental Groups to Enhance Coordination and Promote Responsible Domestic Production of Oil and Gas Resources

Science.gov (United States)

EPA News Release: EPA Participates in Energy Roundtable with States, Tribes, Businesses and Environmental Groups to Enhance Coordination and Promote Responsible Domestic Production of Oil and Gas Resources

A new method for calculating gas saturation of low-resistivity shale gas reservoirs

Directory of Open Access Journals (Sweden)

Jinyan Zhang

2017-09-01

Full Text Available The Jiaoshiba shale gas field is located in the Fuling area of the Sichuan Basin, with the Upper Ordovician Wufeng–Lower Silurian Longmaxi Fm as the pay zone. At the bottom of the pay zone, a high-quality shale gas reservoir about 20 m thick is generally developed with high organic contents and gas abundance, but its resistivity is relatively low. Accordingly, the gas saturation calculated by formulas (e.g. Archie using electric logging data is often much lower than the experiment-derived value. In this paper, a new method was presented for calculating gas saturation more accurately based on non-electric logging data. Firstly, the causes for the low resistivity of shale gas reservoirs in this area were analyzed. Then, the limitation of traditional methods for calculating gas saturation based on electric logging data was diagnosed, and the feasibility of the neutron–density porosity overlay method was illustrated. According to the response characteristics of neutron, density and other porosity logging in shale gas reservoirs, a model for calculating gas saturation of shale gas was established by core experimental calibration based on the density logging value, the density porosity and the difference between density porosity and neutron porosity, by means of multiple methods (e.g. the dual-porosity overlay method by optimizing the best overlay coefficient. This new method avoids the effect of low resistivity, and thus can provide normal calculated gas saturation of high-quality shale gas reservoirs. It works well in practical application. This new method provides a technical support for the calculation of shale gas reserves in this area. Keywords: Shale gas, Gas saturation, Low resistivity, Non-electric logging, Volume density, Compensated neutron, Overlay method, Reserves calculation, Sichuan Basin, Jiaoshiba shale gas field

A study of the response of a gas ionization chamber to different sources of ionizing radiation

International Nuclear Information System (INIS)

Zamble-Dieguez, F.E.

1988-05-01

The response of the TAMU Forward Hadron Calorimeter Chambers to neutrons from a 2 39Pu-Be source was investigated in hope of developing a strategy to reduce the effects of the background events called /open quotes/Texas towers/close quotes/ in the CDF trigger for the next run. The response to a standard ( 5 5Fe γ-ray) energy source was also studied and found to be similar to that of the chambers installed at CDF. In addition, the effects of different sampling gases and intermediate absorbers on the rate of large energy pulses were investigated. The neutron data were compared with the energy spectrum measured in CDF and that simulated using Monte Carlo techniques. It was found that the large energy pulse frequency can be reduced by as much as 50% if a non-hydrogenous sampling gas is used in conjunction with a neutron moderator

Recognizing Physisorption and Chemisorption in Carbon Nanotubes Gas Sensors by Double Exponential Fitting of the Response.

Science.gov (United States)

Calvi, Andrea; Ferrari, Alberto; Sbuelz, Luca; Goldoni, Andrea; Modesti, Silvio

2016-05-19

Multi-walled carbon nanotubes (CNTs) have been grown in situ on a SiO 2 substrate and used as gas sensors. For this purpose, the voltage response of the CNTs as a function of time has been used to detect H 2 and CO 2 at various concentrations by supplying a constant current to the system. The analysis of both adsorptions and desorptions curves has revealed two different exponential behaviours for each curve. The study of the characteristic times, obtained from the fitting of the data, has allowed us to identify separately chemisorption and physisorption processes on the CNTs.

Natural Gas Regulation

International Nuclear Information System (INIS)

1995-01-01

The regulation of Natural Gas. Natural gas Regulation clarifies and consolidates the legal and institutional framework for development of the industry through six principal elements: 1) Establishment of a vision of the industry. 2) Development of regulatory objectives. 3) Determination of relationships among industry participants. 4) Clear specification of the role of PEMEX in the industry. 5) Definition of the functions of the Regulatory authority. 6) Creation of a transition regime. In parallel with the development of the substantive legal framework, the law of the Comision Reguladora de Energia (CRE) was also enacted by Congress in October 1995 to strength the institutional framework and implement the legal changes. This law defines the CRE as an agency of the Energy Ministry with technical, operational, and budgetary autonomy, and responsibility for implementing natural gas industry regulation. (Author)

Northern Ireland gas industry

Energy Technology Data Exchange (ETDEWEB)

Anderson, R S [Belfast City Council Gas Dept.; Asquith, R S; Brown, J M; McKay, G

1977-07-01

Throughout Northern Ireland the production of town gas is derived from hydrocarbon feedstocks. In the larger undertakings in Northern Ireland the feedstock is light distillate; a light petroleum feedstock which is a crude gasoline comprised mainly of pentanes, reformed in catalytic plants. The remaining gas undertakings produce a liquefied petroleum gas (LPG)/air mixture using a mixture of either butane or propane and air. The individual gas units and the type of reforming feedstock are shown. A review of the oil-dependence of town gas and electricity production in Northern Ireland has been considered and is mainly responsible for the high fuel prices experienced in the community. A detailed description of the reforming process has been described, and considerable efforts have been made to optimize the process. In spite of substantial economic savings being made on the processing unit, the gas industry is very susceptible to the changes in oil prices which have escalated rapidly in recent years. The difference in gas prices between the United Kingdom and Northern Ireland indicates that North Sea gas would offer major economic benefits to the gas industry in Northern Ireland, which is operating at a substantial loss at the moment. The industrial concerns, which are dependent on gas and therefore paying high fuel costs, suffer in competition with outside companies. The injection of a moderately cheap natural gas supply to the community may encourage industrial expansion and provide work in a high unemployment area. Although substantial costs must be incurred in distribution pipelines and burner conversions if Northern Ireland changes to natural gas, there appears to be a strong case to introduce North Sea gas in the near future.

Sensitivity analysis and economic optimization studies of inverted five-spot gas cycling in gas condensate reservoir

Directory of Open Access Journals (Sweden)

Shams Bilal

2017-08-01

Full Text Available Gas condensate reservoirs usually exhibit complex flow behaviors because of propagation response of pressure drop from the wellbore into the reservoir. When reservoir pressure drops below the dew point in two phase flow of gas and condensate, the accumulation of large condensate amount occurs in the gas condensate reservoirs. Usually, the saturation of condensate accumulation in volumetric gas condensate reservoirs is lower than the critical condensate saturation that causes trapping of large amount of condensate in reservoir pores. Trapped condensate often is lost due to condensate accumulation-condensate blockage courtesy of high molecular weight, heavy condensate residue. Recovering lost condensate most economically and optimally has always been a challenging goal. Thus, gas cycling is applied to alleviate such a drastic loss in resources.

Estimation of demand function on natural gas and study of demand analysis

Energy Technology Data Exchange (ETDEWEB)

Kim, Y.D. [Korea Energy Economics Institute, Euiwang (Korea, Republic of)

1998-04-01

Demand Function is estimated with several methods about the demand on natural gas, and analyzed per usage. Since the demand on natural gas, which has big share of heating use, has a close relationship with temperature, the inter-season trend of price and income elasticity is estimated considering temperature and economic formation. Per usage response of natural gas demand on the changes of price and income is also estimated. It was estimated that the response of gas demand on the changes of price and income occurs by the change of number of users in long term. In case of the response of unit consumption, only industrial use shows long-term response to price. Since gas price barely responds to the change of exchange rate, it seems to express the price-making mechanism that does not reflect timely the import condition such as exchange rate, etc. 16 refs., 12 figs., 13 tabs.

Studies on Gas Sensing Performance of Pure and Surface Chrominated Indium Oxide Thick Film Resistors

Directory of Open Access Journals (Sweden)

D. N. CHAVAN

2010-12-01

Full Text Available The thick films of AR grade In2O3 were prepared by standard screen-printing technique. The gas sensing performance of thick film was tested for various gases. It showed maximum gas response to ethanol vapor at 350 oC for 80 ppm. To improve the gas response and selectivity of the film towards a particular gas, In2O3 thick films were modified by dipping them in an aqueous solution of 0.1 M CrO3 for different intervals of time. The surface chrominated (20 min In2O3 thick film showed maximum response to H2S gas (40 ppm than pure In2O3 thick film at 250 oC. Chromium oxide on the surface of the film shifts the gas response from ethanol vapor to H2S gas. A systematic study of sensing performance of the sensor indicates the key role played by chromium oxide on the surface of thick film. The selectivity, gas response and recovery time of the sensor were measured and presented.

Offshore industry: medical emergency response in the offshore oil and gas industry.

Science.gov (United States)

Ponsonby, Will; Mika, Frano; Irons, Greg

2009-08-01

The hunt for oil and gas has taken workers into new more distant locations including those offshore. The remoteness of the offshore platforms and vessels coupled with the potential risk of being cut off by bad weather presents particular challenges for medical emergency response (MER). Firstly to define the challenges for MER in terms of locations, population and epidemiology of injuries and illnesses in the offshore environment. Secondly to give examples of legal requirements and industry standards to manage MER. Thirdly to look at existing and emerging practice to manage these challenges. A review of published literature was supplemented with a summary of current practice in the industry. Medical professionals (medics) working offshore on installations and vessels are primarily responsible for the medical care of the workers. The medics have clinics with suitable medical equipment for managing emergencies as well as providing limited primary care. Some countries have legislation that stipulate minimum requirements. Where there is no national legislation, industry and company guidance is used to define the MER standards. Supervision of the offshore medics is often provided by doctors on shore via radio and phone links. These methods of communication are now being augmented with more sophisticated telemedicine solutions such as the Internet and live video links. These newer solutions allow for prompt high-quality care and provide the scope for a variety of new treatment options to be available for the offshore workforce.

Leaf age affects the responses of foliar injury and gas exchange to tropospheric ozone in Prunus serotina seedlings

Energy Technology Data Exchange (ETDEWEB)

Zhang Jianwei, E-mail: jianweizhang@fs.fed.u [Environmental Resources Research Institute, Pennsylvania State University, University Park, PA 16802 (United States); School of Forest Resources, Pennsylvania State University, University Park, PA 16802 (United States); Schaub, Marcus; Ferdinand, Jonathan A. [Environmental Resources Research Institute, Pennsylvania State University, University Park, PA 16802 (United States); Skelly, John M. [Department of Plant Pathology, Pennsylvania State University, University Park, PA 16802 (United States); Steiner, Kim C. [School of Forest Resources, Pennsylvania State University, University Park, PA 16802 (United States); Savage, James E. [Department of Plant Pathology, Pennsylvania State University, University Park, PA 16802 (United States)

2010-08-15

We investigated the effect of leaf age on the response of net photosynthesis (A), stomatal conductance (g{sub wv}), foliar injury, and leaf nitrogen concentration (N{sub L}) to tropospheric ozone (O{sub 3}) on Prunus serotina seedlings grown in open-plots (AA) and open-top chambers, supplied with either carbon-filtered or non-filtered air. We found significant variation in A, g{sub wv}, foliar injury, and N{sub L} (P < 0.05) among O{sub 3} treatments. Seedlings in AA showed the highest A and g{sub wv} due to relatively low vapor pressure deficit (VPD). Older leaves showed significantly lower A, g{sub wv}, N{sub L}, and higher foliar injury (P < 0.001) than younger leaves. Leaf age affected the response of A, g{sub wv}, and foliar injury to O{sub 3}. Both VPD and N{sub L} had a strong influence on leaf gas exchange. Foliar O{sub 3}-induced injury appeared when cumulative O{sub 3} uptake reached 8-12 mmol m{sup -2}, depending on soil water availability. The mechanistic assessment of O{sub 3}-induced injury is a valuable approach for a biologically relevant O{sub 3} risk assessment for forest trees. - Ozone effects on symptom development and leaf gas exchange interacted with leaf age and N-content on black cherry seedlings.

Effects of flow rate and gas mixture on the welfare of weaned and neonate pigs during gas euthanasia.

Science.gov (United States)

Sadler, L J; Hagen, C D; Wang, C; Widowski, T M; Johnson, A K; Millman, S T

2014-02-01

The objectives of this study were to assess efficacy and welfare implications of gas euthanasia when applied to weaned and neonate pigs. Parameters associated with welfare, which were measured before loss of consciousness, included open-mouth breathing, ataxia, righting response, and escape attempts. Two age groups (weaned and neonate) were assessed in 9 gas treatments arranged in a 2 × 4 factorial design, with 2 gas types (CO2 = 100% CO2 and 50:50 = 50:50 CO2:argon) and 4 flow rates (box volume exchange/min: slow = 20%; medium = 35%; fast = 50%; prefill = prefilled followed by 20%) and a control treatment in which ambient air was passed through the box. Pig pairs (10/treatment) were placed in a modified Euthanex AgPro system (Euthanex Corp., Palmer, PA). Behavioral and physiological responses were observed directly and from video recordings for latency, duration, prevalence (percent of pigs affected), and frequency (number of occurrences/pig). Data were analyzed as linear mixed models or with a Cox proportional hazard model as appropriate. Piglet pair was the experimental unit. For the weaned pig, welfare was superior with CO2 relative to 50:50 within 1 or more flow rates on the basis of reduced duration of open-mouth breathing, duration of ataxia, frequency of escape attempts, and duration and frequency of righting response (P euthanasia. As such, a 50:50 CO2:argon gas mixture and slower flow rates should be avoided when euthanizing weaned or neonate pigs with gas methods. Neonate pigs succumb to the effects of gas euthanasia quicker than weaned pigs and display fewer signs of distress.

Genetic Analysis of Gravity Signal Transduction in Arabidopsis thaliana Seedlings

Science.gov (United States)

Boonsirichai, K.; Harrison, B.; Stanga, J.; Young, L.-S.; Neal, C.; Sabat, G.; Murthy, N.; Harms, A.; Sedbrook, J.; Masson, P.

The primary roots of Arabidopsis thaliana seedlings respond to gravity stimulation by developing a tip curvature that results from differential cellular elongation on opposite flanks of the elongation zone. This curvature appears modulated by a lateral gradient of auxin that originates in the gravity-perceiving cells (statocytes) of the root cap through an apparent lateral repositioning of a component the auxin efflux carrier complex within these cells (Friml et al, 2002, Nature 415: 806-809). Unfortunately, little is known about the molecular mechanisms that govern early phases of gravity perception and signal transduction within the root-cap statocytes. We have used a molecular genetic approach to uncover some of these mechanisms. Mutations in the Arabidopsis ARG1 and ARL2 genes, which encode J-domain proteins, resulted in specific alterations in root and hypocotyl gravitropism, without pleiotropic phenotypes. Interestingly, ARG1 and ARL2 appear to function in the same genetic pathway. A combination of molecular genetic, biochemical and cell-biological approaches were used to demonstrate that ARG1 functions in early phases of gravity signal transduction within the root and hypocotyl statocytes, and is needed for efficient lateral auxin transport within the cap. The ARG1 protein is associated with components of the secretory and/or endosomal pathways, suggesting its role in the recycling of components of the auxin efflux carrier complex between plasma membrane and endosome (Boonsirichai et al, 2003, Plant Cell 15:2612-2625). Genetic modifiers of arg1-2 were isolated and shown to enhance the gravitropic defect of arg1-2, while resulting in little or no gravitropic defects in a wild type ARG1 background. A slight tendency for arg1-2;mar1-1 and arg1-2;mar2-1 double-mutant organs to display an opposite gravitropic response compared to wild type suggests that all three genes contribute to the interpretation of the gravity-vector information by seedling organs. The

Natural gas in the transportation sector

Energy Technology Data Exchange (ETDEWEB)

Ask, T Oe; Einang, P M; Stenersen, D [MARINTEK (Norway)

1996-12-01

The transportation sector is responsible for more than 50% of all oil products consumed, and it is the fastest growing oil demand sector and the fastest growing source of emissions. During the last 10 years there have been a considerable and growing effort in developing internal combustion gas engines. This effort has resulted in gas engines with efficiencies comparable to the diesel engines and with emissions considerably lower than engines burning conventional fuels. This development offers us opportunities to use natural gas very efficiently also in the transportation sector, resulting in reduced emissions. However, to utilize all the built in abilities natural gas has as engine fuel, the natural gas composition must be kept within relatively narrow limits. This is the case with both diesel and gasoline today. A further development require therefore specified natural gas compositions, and the direct use of pipeline natural gas as today would only in limited areas be acceptable. An interesting possibility for producing a specified natural gas composition is by LNG (Liquid Natural Gas) production. (EG)

Gas cooled traction drive inverter

Science.gov (United States)

Chinthavali, Madhu Sudhan

2013-10-08

The present invention provides a modular circuit card configuration for distributing heat among a plurality of circuit cards. Each circuit card includes a housing adapted to dissipate heat in response to gas flow over the housing. In one aspect, a gas-cooled inverter includes a plurality of inverter circuit cards, and a plurality of circuit card housings, each of which encloses one of the plurality of inverter cards.

Morphological response to a North Sea bed depression induced by gas mining

NARCIS (Netherlands)

Fluit, C.C.J.M.; Hulscher, Suzanne J.M.H.

2002-01-01

Gas mining leads to saucer-like surface depressions. In the North Sea, gas is currently mined at several offshore locations. The associated bed depression has a similar spatial extent as offshore tidal sandbanks, which are large-scale bed patterns covering a significant part of the North Sea bottom.

Sensitivity and environmental response of the CMS RPC gas gain monitoring system

CERN Document Server

Benussi, L.; Colafranceschi, S.; Fabbri, F.L.; Giardoni, M.; Ortenzi, B.; Paolozzi, A.; Passamonti, L.; Pierluigi, D.; Ponzio, B.; Russo, A.; Colaleo, A.; Loddo, F.; Maggi, M.; Ranieri, A.; Abbrescia, M.; Iaselli, G.; Marangelli, B.; Natali, S.; Nuzzo, S.; Pugliese, G.; Romano, F.; Roselli, G.; Trentadue, R.; Tupputi, S.; Guida, R.; Polese, G.; Sharma, A.; Cimmino, A.; Lomidze, D.; Paolucci, D.; Piccolo, P.; Baesso, P.; Necchi, M.; Pagano, D.; Ratti, S.P.; Vitulo, P.; Viviani, C.

Results from the gas gain monitoring (GGM) system for the muon detector using RPC in the CMS experiment at the LHC is presented. The system is designed to provide fast and accurate determination of any shift in the working point of the chambers due to gas mixture changes.

Visualization of Atomization Gas Flow and Melt Break-up Effects in Response to Nozzle Design

Energy Technology Data Exchange (ETDEWEB)

Anderson, Iver; Rieken, Joel; Meyer, John; Byrd, David; Heidloff, Andy

2011-04-01

Both powder particle size control and efficient use of gas flow energy are highly prized goals for gas atomization of metal and alloy powder to minimize off-size powder inventory (or 'reverb') and excessive gas consumption. Recent progress in the design of close-coupled gas atomization nozzles and the water model simulation of melt feed tubes were coupled with previous results from several types of gas flow characterization methods, e.g., aspiration measurements and gas flow visualization, to make progress toward these goals. Size distribution analysis and high speed video recordings of gas atomization reaction synthesis (GARS) experiments on special ferritic stainless steel alloy powders with an Ar+O{sub 2} gas mixture were performed to investigate the operating mechanisms and possible advantages of several melt flow tube modifications with one specific gas atomization nozzle. In this study, close-coupled gas atomization under closed wake gas flow conditions was demonstrated to produce large yields of ultrafine (dia.<20 {mu}m) powders (up to 32%) with moderate standard deviations (1.62 to 1.99). The increased yield of fine powders is consistent with the dual atomization mechanisms of closed wake gas flow patterns in the near-field of the melt orifice. Enhanced size control by stabilized pre-filming of the melt with a slotted trumpet bell pour tube was not clearly demonstrated in the current experiments, perhaps confounded by the influence of the melt oxidation reaction that occurred simultaneously with the atomization process. For this GARS variation of close-coupled gas atomization, it may be best to utilize the straight cylindrical pour tube and closed wake operation of an atomization nozzle with higher gas mass flow to promote the maximum yields of ultrafine powders that are preferred for the oxide dispersion strengthened alloys made from these powders.

The Eastring gas pipeline in the context of the Central and Eastern European gas supply challenge

Science.gov (United States)

Mišík, Matúš; Nosko, Andrej

2017-11-01

Ever since the 2009 natural gas crisis, energy security has been a crucial priority for countries of Central and Eastern Europe. Escalating in 2014, the conflict between Ukraine and Russia further fuelled negative expectations about the future development of energy relations for the region predominantly supplied by Russia. As a response to the planned cessation of gas transit through the Brotherhood pipeline, which brings Russian gas to Europe via Ukraine and Slovakia, the Slovak transmission system operator Eustream proposed the Eastring pipeline. This Perspective analyses this proposal and argues that neither the perceived decrease in Slovak energy security nor the loss of economic rent from the international gas transit should be the main policy driver behind such a major infrastructure project. Although marketed as an answer to current Central and Eastern European gas supply security challenges, the Eastring pipeline is actually mainly focused on issues connected to the Slovak gas transit.

Oil and gas site contamination risks : improved oversight needed

International Nuclear Information System (INIS)

2010-02-01

British Columbia has seen record levels of activities in the oil and gas sector. Upstream petroleum processes include exploration, well completion and production. Site contamination can occur during all of these activities, resulting in potential environmental and human health impacts. Although well operators are responsible by law for site restoration, there is a potential risk that some operators will not fulfill their responsibilities, thereby leaving the province liable for the site restoration costs. In British Columbia, the BC Oil and Gas Commission (OGC) is responsible for managing these risks through oversight activities designed to ensure that industry meets its obligations. The OGC also manages the orphan sites reclamation fund. This report presented an audit of the OGC in order to determine if it is providing adequate oversight of upstream oil and gas site contamination risks. The audit examined whether the agency responsibilities are clear and whether the OGC is fully aware of the environmental and financial risks associated with upstream oil and gas site contamination. The audit also examined if the OGC has established appropriate procedures to oversee the risks and to inform the public of how effectively site contamination risks are being managed. The report presented the audit background, audit expectations, findings, conclusions and recommendations. It was concluded that the OGC's oversight of the environmental and financial risks associated with oil and gas site contamination needs improving. tabs., figs.

Semiconducting oxide gas-sensitive resistors

International Nuclear Information System (INIS)

Dusastre, V.J.

1998-01-01

The overall aim of this thesis is to describe the gas sensing behaviour of a wide range of metal oxide semiconductors which exhibit tremendous changes in their electrical resistance at high temperatures (typically > 300 deg. C) upon exposure to traces (ppm) of reactive gases present in the air. The effects of surface segregation in antimony-doped tin dioxide (Sn 1-y Sb y O 2 ) on both the electrical response to water vapour and the catalytic combustion of methane in the presence of water vapour were demonstrated. Effects of microstructure, and especially particle size, on the behaviour (sensitivity and selectivity) of these compounds to carbon monoxide and methane were also demonstrated. A change in behaviour correlating with the Debye length was shown. Theoretical calculation methods were used to model surface segregation and surface defects. Antimony segregates as Sb 3+ and the complex (Sn(II).V o ) is a stable surface species. A model for gas response and surface reaction involving this complex is proposed. The properties of solid solution series prepared by systematic cation substitution as a way of understanding the gas response mechanism linked to the surface chemistry has been examined in (CrNbO 4 )x(Sn 1-y Sb y O 2 ) 1-x , Ti x (Sn 1-y Sb y ) 1-x O 2 , and (MWO 4 )x([Sn-Ti]O 2 ) 1x [with M: Mn, Fe, Co, Ni, Cu, Zn]. Effects of stoichiometry, microstructure, combustion gradient and surface segregation on gas (water, carbon monoxide, methane, propane and ammonia) sensitivity and selectivity have been observed and discussed. (author)

US crude oil, natural gas, and natural gas liquids reserves: 1990 annual report

International Nuclear Information System (INIS)

1991-09-01

The primary focus of this report is to provide an accurate estimate of US proved reserves of crude oil, natural gas, and natural gas liquids. These estimates were considered essential to the development, implementation, and evaluation of natural energy policy and legislation. In the past, the government and the public relied upon industry estimates of proved reserves. These estimates were prepared jointly by the American Petroleum Institute (API) and the American Gas Association (AGA) and published in their annual report, Reserves of Crude Oil, Natural Gas Liquids, and Natural Gas in the United States and Canada. However, API and AGA ceased publication of reserves estimates after their 1979 report. By the mid-1970's, various federal agencies had separately established programs to collect data on, verify, or independently estimate domestic proved reserves of crude oil or natural gas. Each program was narrowly defined to meet the particular needs of the sponsoring agency. In response to recognized need for unified, comprehensive proved reserves estimates, Congress in 1977 required the Department of Energy to prepare such estimates. To meet this requirement, the EIA's reserves program was undertaken to establish a unified, verifiable, comprehensive, and continuing statistical series for proved reserves of crude oil and natural gas. The program was expanded to include proved reserves of natural gas liquids in the 1979 report. 36 refs., 11 figs., 16 tabs

Sensing characteristics of nanocrystalline bismuth oxide clad-modified fiber optic gas sensor

Science.gov (United States)

Manjula, M.; Karthikeyan, B.; Sastikumar, D.

2017-08-01

Gas sensing properties of nanocrystalline bismuth oxide clad - modified fiber optic sensor is reported for ammonia, ethanol, methanol and acetone gasses at room temperature. The output of sensor increases or decreases for certain gasses when the concentration of the gas is increased. The sensor exhibits high response and good selectivity to methanol gas. Time response characteristics of the sensor are also reported.

Hydrogen gas sensing feature of polyaniline/titania (rutile) nanocomposite at environmental conditions

Energy Technology Data Exchange (ETDEWEB)

Milani Moghaddam, Hossain, E-mail: hossainmilani@yahoo.com [Solid State Physics Department, University of Mazandaran, Babolsar (Iran, Islamic Republic of); Nasirian, Shahruz [Solid State Physics Department, University of Mazandaran, Babolsar (Iran, Islamic Republic of); Basic Sciences Department, Mazandaran University of Science and Technology, Babol (Iran, Islamic Republic of)

2014-10-30

Graphical abstract: - Highlights: • Polyaniline/titania (rutile) nanocomposite (TPNC) was synthesized by a chemical oxidative polymerization method. • Surface morphology and titania (rutile) wt% in TPNC sensors were significant factors for H{sub 2} gas sensing. • TPNC sensors could be used for H{sub 2} gas sensing at different R.H. humidity. • TPNC Sensors exhibited considerable sensitive, reversible and repeatable response to H{sub 2} gas at environmental conditions. - Abstract: The resistance-based sensors of polyaniline/titania (rutile) nanocomposite (TPNC) were prepared by spin coating technique onto an epoxy glass substrate with Cu-interdigited electrodes to study their hydrogen (H{sub 2}) gas sensing features. Our findings are that the change of the surface morphology, porosity and wt% of titania in TPNCs have a significant effect on H{sub 2} gas sensing of sensors. All of the sensors had a reproducibility response toward 0.8 vol% H{sub 2} gas at room temperature, air pressure and 50% relative humidity. A sensor with 40 wt% of titania nanoparticles had better response/recovery time and the response than other sensors. Moreover, H{sub 2} gas sensing mechanism of TPNC sensors based contact areas and the correlation of energy levels between PANI chains and the titania grains were studied.

Process optimization for microcystin-LR degradation by Response Surface Methodology and mechanism analysis in gas-liquid hybrid discharge system.

Science.gov (United States)

Zhang, Yi; Wei, Hanyu; Xin, Qing; Wang, Mingang; Wang, Qi; Wang, Qiang; Cong, Yanqing

2016-12-01

A gas-liquid hybrid discharge system was applied to microcystin-LR (MC-LR) degradation. MC-LR degradation was completed after 1 min under a pulsed high voltage of 16 kV, gas-liquid interface gap of 10 mm and oxygen flow rate of 160 L/h. The Box-Behnken Design was proposed in Response Surface Methodology to evaluate the influence of pulsed high voltage, electrode distance and oxygen flow rate on MC-LR removal efficiency. Multiple regression analysis, focused on multivariable factors, was employed and a reduced cubic model was developed. The ANOVA analysis shows that the model is significant and the model prediction on MC-LR removal was also validated with experimental data. The optimum conditions for the process are obtained at pulsed voltage of 16 kV, gas-liquid interface gap of 10 mm and oxygen flow rate of 120 L/h with ta removal efficiency of MC-LR of 96.6%. The addition of catalysts (TiO 2 or Fe 2+ ) in the gas-liquid hybrid discharge system was found to enhance the removal of MC-LR. The intermediates of MC-LR degradation were analyzed by liquid chromatography/mass spectrometry. The degradation pathway proposed envisaged the oxidation of hydroxyl radicals and ozone, and attack of high-energy electrons on the unsaturated double bonds of Adda and Mdha, with MC-LR finally decomposing into small molecular products. Copyright © 2016 Elsevier Ltd. All rights reserved.

CdO Doped Indium Oxide Thick Film as a Low Temperature H2S Gas Sensor

Directory of Open Access Journals (Sweden)

D. N. CHAVAN

2011-06-01

Full Text Available The thick films of AR grade In2O3 were prepared by standard screen-printing technique. The gas sensing performance of thick film was tested for various gases. It showed maximum gas response to ethanol vapor at 350 oC for 80 ppm. To improve the gas response and selectivity of the film towards a particular gas, In2O3 thick films were modified by dipping them in an aqueous solution of 0.1 M CdCl2 for different intervals of time. The surface modified (10 min In2O3 thick film showed maximum response to H2S gas (10 ppm than pure In2O3 thick film at 150 oC. Cadmium oxide on the surface of the film shifts the gas response from ethanol vapor to H2S gas. A systematic study of sensing performance of the thick films indicates the key role played by cadmium oxide on the surface of thick films. The selectivity, gas response and recovery time of the thick films were measured and presented.

Characterizing the drivers of seedling leaf gas exchange responses to warming and altered precipitation: indirect and direct effects.

Science.gov (United States)

Smith, Nicholas G; Pold, Grace; Goranson, Carol; Dukes, Jeffrey S

2016-01-01

Anthropogenic forces are projected to lead to warmer temperatures and altered precipitation patterns globally. The impact of these climatic changes on the uptake of carbon by the land surface will, in part, determine the rate and magnitude of these changes. However, there is a great deal of uncertainty in how terrestrial ecosystems will respond to climate in the future. Here, we used a fully factorial warming (four levels) by precipitation (three levels) manipulation experiment in an old-field ecosystem in the northeastern USA to examine the impact of climatic changes on leaf carbon exchange in five species of deciduous tree seedlings. We found that photosynthesis generally increased in response to increasing precipitation and decreased in response to warming. Respiration was less sensitive to the treatments. The net result was greater leaf carbon uptake in wetter and cooler conditions across all species. Structural equation modelling revealed the primary pathway through which climate impacted leaf carbon exchange. Net photosynthesis increased with increasing stomatal conductance and photosynthetic enzyme capacity (V cmax ), and decreased with increasing respiration of leaves. Soil moisture and leaf temperature at the time of measurement most heavily influenced these primary drivers of net photosynthesis. Leaf respiration increased with increasing soil moisture, leaf temperature, and photosynthetic supply of substrates. Counter to the soil moisture response, respiration decreased with increasing precipitation amount, indicating that the response to short- (i.e. soil moisture) versus long-term (i.e. precipitation amount) water stress differed, possibly as a result of changes in the relative amounts of growth and maintenance demand for respiration over time. These data (>500 paired measurements of light and dark leaf gas exchange), now publicly available, detail the pathways by which climate can impact leaf gas exchange and could be useful for testing assumptions in

Gas Selectivity Control in Co3O4 Sensor via Concurrent Tuning of Gas Reforming and Gas Filtering using Nanoscale Hetero-Overlayer of Catalytic Oxides.

Science.gov (United States)

Jeong, Hyun-Mook; Jeong, Seong-Yong; Kim, Jae-Hyeok; Kim, Bo-Young; Kim, Jun-Sik; Abdel-Hady, Faissal; Wazzan, Abdulaziz A; Al-Turaif, Hamad Ali; Jang, Ho Won; Lee, Jong-Heun

2017-11-29

Co 3 O 4 sensors with a nanoscale TiO 2 or SnO 2 catalytic overlayer were prepared by screen-printing of Co 3 O 4 yolk-shell spheres and subsequent e-beam evaporation of TiO 2 and SnO 2 . The Co 3 O 4 sensors with 5 nm thick TiO 2 and SnO 2 overlayers showed high responses (resistance ratios) to 5 ppm xylene (14.5 and 28.8) and toluene (11.7 and 16.2) at 250 °C with negligible responses to interference gases such as ethanol, HCHO, CO, and benzene. In contrast, the pure Co 3 O 4 sensor did not show remarkable selectivity toward any specific gas. The response and selectivity to methylbenzenes and ethanol could be systematically controlled by selecting the catalytic overlayer material, varying the overlayer thickness, and tuning the sensing temperature. The significant enhancement of the selectivity for xylene and toluene was attributed to the reforming of less reactive methylbenzenes into more reactive and smaller species and oxidative filtering of other interference gases, including ubiquitous ethanol. The concurrent control of the gas reforming and oxidative filtering processes using a nanoscale overlayer of catalytic oxides provides a new, general, and powerful tool for designing highly selective and sensitive oxide semiconductor gas sensors.

Ether gas-sensor based on Au nanoparticles-decorated ZnO microstructures

Directory of Open Access Journals (Sweden)

Roberto López

Full Text Available An ether gas-sensor was fabricated based on gold nanoparticles (Au-NPs decorated zinc oxide microstructures (ZnO-MS. Scanning electron microscope (SEM and high-resolution transmission electron microscope (HRTEM measurements were performed to study morphological and structural properties, respectively, of the ZnO-MS. The gas sensing response was evaluated in a relatively low temperature regime, which ranged between 150 and 250 °C. Compared with a sensor fabricated from pure ZnO-MS, the sensor based on Au-NPs decorated ZnO-MS showed much better ether gas response at the highest working temperature. In fact, pure ZnO-MS based sensor only showed a weak sensitivity of about 25%. The improvement of the ether gas response for sensor fabricated with Au-NPs decorated ZnO-MS was attributed to the catalytic activity of the Au-NPs. Keywords: ZnO microstructures, Au nanoparticles, Ether, Gas sensor

Snowflake-Shaped ZnO Nanostructures-Based Gas Sensor for Sensitive Detection of Volatile Organic Compounds

Directory of Open Access Journals (Sweden)

Tianli Han

2017-01-01

Full Text Available Volatile organic compounds (VOCs have been considered severe risks to human health. Gas sensors for the sensitive detection of VOCs are highly required. However, the preparation of gas-sensing materials with a high gas diffusion performance remains a great challenge. Here, through a simple hydrothermal method accompanied with a subsequent thermal treatment, a special porous snowflake-shaped ZnO nanostructure was presented for sensitive detection of VOCs including diethyl ether, methylbenzene, and ethanol. The fabricated gas sensors exhibit a good sensing performance including high responses to VOCs and a short response/recovery time. The responses of the ZnO-based gas sensor to 100 ppm ethanol, methylbenzene, and diethyl ether are about 27, 21, and 11, respectively, while the response times to diethyl ether and methylbenzene are less than 10 seconds. The gas adsorption-desorption kinetics is also investigated, which shows that the gas-sensing behaviors to different target gases are remarkably different, making it possible for target recognition in practical applications.

A dwarf wheat mutant is associated with increased drought ...

African Journals Online (AJOL)

... was significantly higher than Jingdong 6. Most of the s-dwarf seedlings survived in recovering experiement after water loss. The stalk of s-dwarf seedling also showed reduced gravitropism. This is the first report about a new dwarf wheat mutant associated with increased drought resistance and altered stalk gravitropism.

Adenovirus Detection by the cGAS/STING/TBK1 DNA Sensing Cascade

Science.gov (United States)

Lam, Eric; Stein, Saskia

2014-01-01

Adenovirus (Ad) infection triggers a cell-specific antiviral response following exposure of viral DNA to the intracellular compartment. A variety of DNA sensors (DAI, AIM2, DDx41, RNA polymerase [Pol] III, and IFI16 [p204]) have been identified in recent years; however, the DNA sensor involved in detection of adenovirus has not been established. Cyclic GMP-AMP synthase (cGAS), a DNA sensor that produces a cyclic guanine-adenine dinucleotide (cGAMP) inducer of STING, has been examined to determine its role in generating an antiadenoviral response. Short hairpin RNA (shRNA) lentiviral vectors targeting TBK1, STING, and cGAS were established in murine MS1 endothelial and RAW 264.7 macrophage cell lines. Knockdown of TBK1, STING, and cGAS results in a dramatic reduction in the activation of the primary antiviral response marker phosphorylated interferon (IFN) response factor 3 (IRF3) following exposure to adenovirus. Furthermore, activation of secondary type I IFN signaling targets (ptyrSTAT1 and ptyrSTAT2 [ptyrSTAT1/2]) was also compromised. Consistent with compromised activation of primary and secondary response markers, transcriptional activation of IRF3-responsive genes (beta IFN [IFN-β], ISG15, ISG54) and secondary response transcripts were diminished in cells knocked down in cGAS, STING, or TBK1. These data establish cGAS as the dominant cytosolic DNA sensor responsible for detection of internalized adenovirus leading to induction of the type I interferon antiviral cascade. PMID:24198409

A Novel Design of Rescue Capsule considering the Pressure Characteristics and Thermal Dynamic Response with Thermomechanical Coupling Action Subjected to Gas Explosion Load

Directory of Open Access Journals (Sweden)

Xiaowei Zhai

2017-01-01

Full Text Available To ensure the structural safety and reliability of coal mine rescue capsule in disastrous surroundings after gas explosion, in this paper, the thermomechanical coupling effect on a certain structure subjected to gas explosion was analyzed, and then a novel rescue capsule with a combination of radius and square features was designed according to the underground surroundings and relevant regulations on mine rescue devices. Foremost, the coupling mechanism of thermal-fluid-solid interaction between gas explosion shock wave and rescue capsule and the thermal dynamic response of the capsule subjected to explosion load of gas/air mixture was investigated and revealed by employing LS-DYNA. The variation laws and characteristics of stress field, displacement field, and temperature field of the capsule were analyzed based on the simulation results. Results show that the structural safety, tightness, and reliability of the capsule meet the requirements of the national safety regulations. The design method presented in this work provides a new thought for design of coal mine rescue capsule.

Signal perception, transduction, and response in gravity resistance. Another graviresponse in plants

Science.gov (United States)

Hoson, T.; Saito, Y.; Soga, K.; Wakabayashi, K.

Resistance to the gravitational force is a serious problem that plants have had to solve to survive on land. Mechanical resistance to the pull of gravity is thus a principal graviresponse in plants, comparable to gravitropism. Nevertheless, only limited information has been obtained for this gravity response. We have examined the mechanism of gravity-induced mechanical resistance using hypergravity conditions produced by centrifugation. As a result, we have clarified the outline of the sequence of events leading to the development of mechanical resistance. The gravity signal may be perceived by mechanoreceptors (mechanosensitive ion channels) on the plasma membrane and it appears that amyloplast sedimentation in statocytes is not involved. Transformation and transduction of the perceived signal may be mediated by the structural or physiological continuum of microtubule-cell membrane-cell wall. As the final step in the development of mechanical resistance, plants construct a tough body by increasing cell wall rigidity. The increase in cell wall rigidity is brought about by modification of the metabolism of certain wall constituents and modification of the cell wall environment, especially pH. We need to clarify the details of each step by future space and ground-based experiments.

Carbon-Nanotube-Based Chemical Gas Sensor

Science.gov (United States)

Kaul, Arunpama B.

2010-01-01

Conventional thermal conductivity gauges (e.g. Pirani gauges) lend themselves to applications such as leak detectors, or in gas chromatographs for identifying various gas species. However, these conventional gauges are physically large, operate at high power, and have a slow response time. A single-walled carbon-nanotube (SWNT)-based chemical sensing gauge relies on differences in thermal conductance of the respective gases surrounding the CNT as it is voltage-biased, as a means for chemical identification. Such a sensor provides benefits of significantly reduced size and compactness, fast response time, low-power operation, and inexpensive manufacturing since it can be batch-fabricated using Si integrated-circuit (IC) process technology.

Gas Centrifuges and Nuclear Proliferation

Energy Technology Data Exchange (ETDEWEB)

Albright, David

2004-09-15

Gas centrifuges have been an ideal enrichment method for a wide variety of countries. Many countries have built gas centrifuges to make enriched uranium for peaceful nuclear purposes. Other countries have secretly sought centrifuges to make highly enriched uranium for nuclear weapons. In more recent times, several countries have secretly sought or built gas centrifuges in regions of tension. The main countries that have been of interest in the last two decades have been Pakistan, Iraq, Iran, and North Korea. Currently, most attention is focused on Iran, Pakistan, and North Korea. These states did not have the indigenous abilities to make gas centrifuges, focusing instead on illicit and questionable foreign procurement. The presentation covered the following main sections: Spread of centrifuges through illicit procurement; Role of export controls in stopping proliferation; Increasing the transparency of gas centrifuge programs in non-nuclear weapon states; and, Verified dismantlement of gas centrifuge programs. Gas centrifuges are important providers of low enriched uranium for civil nuclear power reactors. They also pose special nuclear proliferation risks. We all have special responsibilities to prevent the spread of gas centrifuges into regions of tension and to mitigate the consequences of their spread into the Middle East, South Asia, and North Asia.

Gas selectivity of SILAR grown CdS nano-bulk junction

Science.gov (United States)

Jayakrishnan, R.; Nair, Varun G.; Anand, Akhil M.; Venugopal, Meera

2018-03-01

Nano-particles of cadmium sulphide were deposited on cleaned copper substrate by an automated sequential ionic layer adsorption reaction (SILAR) system. The grown nano-bulk junction exhibits Schottky diode behavior. The response of the nano-bulk junction was investigated under oxygen and hydrogen atmospheric conditions. The gas response ratio was found to be 198% for Oxygen and 34% for Hydrogen at room temperature. An increase in the operating temperature of the nano-bulk junction resulted in a decrease in their gas response ratio. A logarithmic dependence on the oxygen partial pressure to the junction response was observed, indicating a Temkin isothermal behavior. Work function measurements using a Kelvin probe demonstrate that the exposure to an oxygen atmosphere fails to effectively separate the charges due to the built-in electric field at the interface. Based on the benefits like simple structure, ease of fabrication and response ratio the studied device is a promising candidate for gas detection applications.

Methods for Gas Sensing with Single-Walled Carbon Nanotubes

Science.gov (United States)

Kaul, Anupama B. (Inventor)

2013-01-01

Methods for gas sensing with single-walled carbon nanotubes are described. The methods comprise biasing at least one carbon nanotube and exposing to a gas environment to detect variation in temperature as an electrical response.

Miniaturized Planar Room Temperature Ionic Liquid Electrochemical Gas Sensor for Rapid Multiple Gas Pollutants Monitoring.

Science.gov (United States)

Wan, Hao; Yin, Heyu; Lin, Lu; Zeng, Xiangqun; Mason, Andrew J

2018-02-01

The growing impact of airborne pollutants and explosive gases on human health and occupational safety has escalated the demand of sensors to monitor hazardous gases. This paper presents a new miniaturized planar electrochemical gas sensor for rapid measurement of multiple gaseous hazards. The gas sensor features a porous polytetrafluoroethylene substrate that enables fast gas diffusion and room temperature ionic liquid as the electrolyte. Metal sputtering was utilized for platinum electrodes fabrication to enhance adhesion between the electrodes and the substrate. Together with carefully selected electrochemical methods, the miniaturized gas sensor is capable of measuring multiple gases including oxygen, methane, ozone and sulfur dioxide that are important to human health and safety. Compared to its manually-assembled Clark-cell predecessor, this sensor provides better sensitivity, linearity and repeatability, as validated for oxygen monitoring. With solid performance, fast response and miniaturized size, this sensor is promising for deployment in wearable devices for real-time point-of-exposure gas pollutant monitoring.

Remarkable separability of the circulation response to Arctic sea ice loss and greenhouse gas forcing

Science.gov (United States)

McCusker, K. E.; Kushner, P. J.; Fyfe, J. C.; Sigmond, M.; Kharin, V. V.; Bitz, C. M.

2017-12-01

Arctic sea ice loss has an important effect on local climate through increases in ocean to atmosphere heat flux and associated feedbacks, and may influence midlatitude climate by changing large-scale circulation that can enhance or counter changes that are due to greenhouse gases. The extent to which climate change in a warming world can be understood as greenhouse gas-induced changes that are modulated by Arctic sea ice loss depends on how additive the responses to the separate influences are. Here we use a novel sea ice nudging methodology in the Canadian Earth System Model, which has a fully coupled ocean, to isolate the effects of Arctic sea ice loss and doubled atmospheric carbon dioxide (CO2) to determine their additivity and sensitivity to mean state. We find that the separate effects of Arctic sea ice loss and doubled CO2 are remarkably additive and relatively insensitive to mean climate state. This separability is evident in several thermodynamic and dynamic fields throughout most of the year, from hemispheric to synoptic scales. The extent to which the regional response to sea ice loss sometimes agrees with and sometimes cancels the response to CO2 is quantified. In this model, Arctic sea ice loss enhances the CO2-induced surface air temperature changes nearly everywhere and zonal wind changes over the Pacific sector, whereas sea ice loss counters CO2-induced sea level pressure changes nearly everywhere over land and zonal wind changes over the Atlantic sector. This separability of the response to Arctic sea ice loss from the response to CO2 doubling gives credence to the body of work in which Arctic sea ice loss is isolated from the forcing that modified it, and might provide a means to better interpret the diverse array of modeling and observational studies of Arctic change and influence.

Numerical Study of Particle Interaction in Gas-Particle and Liquid-Particle Flows: Part II Particle Response

Directory of Open Access Journals (Sweden)

K. Mohanarangam

2009-09-01

Full Text Available In this paper the numerical model, which was presented in the first paper (Mohanarangam & Tu; 2009 of this series of study, is employed to study the different particle responses under the influence of two carrier phases namely the gas and the liquid. The numerical model takes into consideration the turbulent behaviour of both the carrier and the dispersed phases, with additional equations to take into account the combined fluid particle behaviour, thereby effecting a two-way coupling. The first paper in this series showed the distinct difference in particulate response both at the mean as well as at the turbulent level for two varied carrier phases. In this paper further investigation has been carried out over a broad range of particle Stokes number to further understand their behaviour in turbulent environments. In order to carry out this prognostic study, the backward facing step geometry of Fessler and Eaton (1999 has been adopted, while the inlet conditions for the carrier as well as the particle phases correspond to that of the experiments of Founti and Klipfel (1998. It is observed that at the mean velocity level the particulate velocities increased with a subsequent increase in the Stokes number for both the GP (Gas-Particle as well as the LP (Liquid-Particle flow. It was also observed that across the Stokes number there was a steady increase in the particulate turbulence for the GP flows with successive increase in Stokes number. However, for the LP flows, the magnitude of the increase in the particulate turbulence across the increasing of Stokes number is not as characteristic as the GP flow. Across the same sections for LP flows the majority of the trend shows a decrease after which they remain more or less a constant.

Novel bacterial gas sensor proteins with transition metal-containing prosthetic groups as active sites.

Science.gov (United States)

Aono, Shigetoshi

2012-04-01

Gas molecules function as signaling molecules in many biological regulatory systems responsible for transcription, chemotaxis, and other complex physiological processes. Gas sensor proteins play a crucial role in regulating such biological systems in response to gas molecules. New sensor proteins that sense oxygen or nitric oxide have recently been found, and they have been characterized by X-ray crystallographic and/or spectroscopic analysis. It has become clear that the interaction between a prosthetic group and gas molecules triggers dynamic structural changes in the protein backbone when a gas sensor protein senses gas molecules. Gas sensor proteins employ novel mechanisms to trigger conformational changes in the presence of a gas. In gas sensor proteins that have iron-sulfur clusters as active sites, the iron-sulfur clusters undergo structural changes, which trigger a conformational change. Heme-based gas sensor proteins reconstruct hydrogen-bonding networks around the heme and heme-bound ligand. Gas sensor proteins have two functional states, on and off, which are active and inactive, respectively, for subsequent signal transduction in response to their physiological effector molecules. To fully understand the structure-function relationships of gas sensor proteins, it is vital to perform X-ray crystal structure analyses of full-length proteins in both the on and off states.

Coalbed methane and tight gas no longer unconventional resources

International Nuclear Information System (INIS)

Gatens, M.

2006-01-01

Unconventional gas refers to natural gas contained in difficult-to-produce formations that require special drilling and completion techniques to achieve commercial production. It includes tight gas, coal seams, organic shales, and gas hydrates. Canada's vast unconventional gas resource is becoming an increasingly important part of the country's gas supply. The emergence of unconventional gas production in Canada over the past several years has made the unconventional increasingly conventional in terms of industry activity. It was suggested that in order to realize the potential for unconventional gas in Canada, all stakeholders should engage to ensure the development is environmentally responsible. Unconventional gas accounts for nearly one third of U.S. gas production. It also accounts for nearly 5 Bcf per day and growing. The impetus to this sudden growth has been the gradual and increasing contribution of tight sands and limes to Canadian production, which accounts for more than 4 Bcf per day. Coalbed methane (CBM) is at 0.5 Bcf per day and growing. In response to expectations that CBM will reach 2 to 3 Bcf per day over the next 2 decades, Canadian producers are placing more emphasis on unconventional resource plays, including organic shales and gas hydrates. As such, significant growth of unconventional gas is anticipated. This growth will be facilitated by the adoption of U.S..-developed technologies and new Canadian technologies. It was suggested that research and development will be key to unlocking the unconventional gas potential. It was also suggested that the already existing, strong regulatory structure should continue in order to accommodate this growth in a sustainable manner. figs

Method and apparatus for preventing overspeed in a gas turbine

Science.gov (United States)

Walker, William E.

1976-01-01

A method and apparatus for preventing overspeed in a gas turbine in response to the rapid loss of applied load is disclosed. The method involves diverting gas from the inlet of the turbine, bypassing the same around the turbine and thereafter injecting the diverted gas at the turbine exit in a direction toward or opposing the flow of gas through the turbine. The injected gas is mixed with the gas exiting the turbine to thereby minimize the thermal shock upon equipment downstream of the turbine exit.

Coulomb sum rules in the relativistic Fermi gas model

International Nuclear Information System (INIS)

Do Dang, G.; L'Huillier, M.; Nguyen Giai, Van.

1986-11-01

Coulomb sum rules are studied in the framework of the Fermi gas model. A distinction is made between mathematical and observable sum rules. Differences between non-relativistic and relativistic Fermi gas predictions are stressed. A method to deduce a Coulomb response function from the longitudinal response is proposed and tested numerically. This method is applied to the 40 Ca data to obtain the experimental Coulomb sum rule as a function of momentum transfer

Maritimes natural gas market : an overview and assessment

International Nuclear Information System (INIS)

Booth, G.

2003-01-01

In 1987, Canada's National Energy Board (NEB) adopted a market-based procedure (MBP) to assess long-term gas exports. The MPB included monitoring and assessment of Maritimes natural gas markets. The NEB is responsible for interprovincial and international oil and gas pipelines as well as tolls and tariffs on NEB-regulated pipelines. The NEB is also responsible for electricity and natural gas exports and exploration programs on federally regulated lands not covered by an Accord agreement. The province of New Brunswick requested a new set of rules for the export of natural gas from the Maritimes to ensure competitiveness with other jurisdictions. The NEB decided that the public interest is best served by allowing the market to work. It also decided that the developing Maritimes market faces several challenges not faced by buyers in the export market. It was concluded that the market is working reasonably well to meet the needs of domestic consumers. 20 per cent of Scotian gas is being used in the Maritimes and many laterals have been constructed to extend service. Most major population centres have natural gas. However, there is no residential or commercial natural gas service in Nova Scotia, and only limited penetration of natural gas in residential and commercial markets in New Brunswick. Maritimers have a long history of using other fuel options and must make capital investment to switch to natural gas. They must, therefore, be convinced that investment will pay off in fuel savings and other benefits. The NEB will have to improve price transparency and strive for regulatory efficiency and cooperation with other jurisdictions. 2 figs

Gene expression polymorphisms and ESTs associated with gravitropic response of subterranean branch meristems and growth habit in Leymus wildryes

Science.gov (United States)

Parminder Kaur; Ivan W. Mott; Steven R. Larson; B. Shaun Bushman; Alvaro G. Hernandez; W. Ryan Kim; Lei Liu; Mark A. Mikel

2008-01-01

Negatively orthogeotropic (NOGT) tiller and diageotropic (DGT) rhizome meristems develop from the same type of lateral axillary meristems and phytomer structure. Although subterranean NOGT and DGT buds appear similar, they display different responses to gravity and perhaps other cues governing branch angle and overall growth habit (GH). Leymus wildryes show remarkable...

On factors influencing air-water gas exchange in emergent wetlands

Science.gov (United States)

Ho, David T.; Engel, Victor C.; Ferron, Sara; Hickman, Benjamin; Choi, Jay; Harvey, Judson W.

2018-01-01

Knowledge of gas exchange in wetlands is important in order to determine fluxes of climatically and biogeochemically important trace gases and to conduct mass balances for metabolism studies. Very few studies have been conducted to quantify gas transfer velocities in wetlands, and many wind speed/gas exchange parameterizations used in oceanographic or limnological settings are inappropriate under conditions found in wetlands. Here six measurements of gas transfer velocities are made with SF6 tracer release experiments in three different years in the Everglades, a subtropical peatland with surface water flowing through emergent vegetation. The experiments were conducted under different flow conditions and with different amounts of emergent vegetation to determine the influence of wind, rain, water flow, waterside thermal convection, and vegetation on air-water gas exchange in wetlands. Measured gas transfer velocities under the different conditions ranged from 1.1 cm h−1 during baseline conditions to 3.2 cm h−1 when rain and water flow rates were high. Commonly used wind speed/gas exchange relationships would overestimate the gas transfer velocity by a factor of 1.2 to 6.8. Gas exchange due to thermal convection was relatively constant and accounted for 14 to 51% of the total measured gas exchange. Differences in rain and water flow among the different years were responsible for the variability in gas exchange, with flow accounting for 37 to 77% of the gas exchange, and rain responsible for up to 40%.

Potential biodefense model applications for portable chlorine dioxide gas production.

Science.gov (United States)

Stubblefield, Jeannie M; Newsome, Anthony L

2015-01-01

Development of decontamination methods and strategies to address potential infectious disease outbreaks and bioterrorism events are pertinent to this nation's biodefense strategies and general biosecurity. Chlorine dioxide (ClO2) gas has a history of use as a decontamination agent in response to an act of bioterrorism. However, the more widespread use of ClO2 gas to meet current and unforeseen decontamination needs has been hampered because the gas is too unstable for shipment and must be prepared at the application site. Newer technology allows for easy, onsite gas generation without the need for dedicated equipment, electricity, water, or personnel with advanced training. In a laboratory model system, 2 unique applications (personal protective equipment [PPE] and animal skin) were investigated in the context of potential development of decontamination protocols. Such protocols could serve to reduce human exposure to bacteria in a decontamination response effort. Chlorine dioxide gas was capable of reducing (2-7 logs of vegetative and spore-forming bacteria), and in some instances eliminating, culturable bacteria from difficult to clean areas on PPE facepieces. The gas was effective in eliminating naturally occurring bacteria on animal skin and also on skin inoculated with Bacillus spores. The culturable bacteria, including Bacillus spores, were eliminated in a time- and dose-dependent manner. Results of these studies suggested portable, easily used ClO2 gas generation systems have excellent potential for protocol development to contribute to biodefense strategies and decontamination responses to infectious disease outbreaks or other biothreat events.

Nanowire-based gas sensors

NARCIS (Netherlands)

Chen, X.; Wong, C.K.Y.; Yuan, C.A.; Zhang, G.

2013-01-01

Gas sensors fabricated with nanowires as the detecting elements are powerful due to their many improved characteristics such as high surface-to-volume ratios, ultrasensitivity, higher selectivity, low power consumption, and fast response. This paper gives an overview on the recent process of the

Hydrogen gas sensing feature of polyaniline/titania (rutile) nanocomposite at environmental conditions

Science.gov (United States)

Milani Moghaddam, Hossain; Nasirian, Shahruz

2014-10-01

The resistance-based sensors of polyaniline/titania (rutile) nanocomposite (TPNC) were prepared by spin coating technique onto an epoxy glass substrate with Cu-interdigited electrodes to study their hydrogen (H2) gas sensing features. Our findings are that the change of the surface morphology, porosity and wt% of titania in TPNCs have a significant effect on H2 gas sensing of sensors. All of the sensors had a reproducibility response toward 0.8 vol% H2 gas at room temperature, air pressure and 50% relative humidity. A sensor with 40 wt% of titania nanoparticles had better response/recovery time and the response than other sensors. Moreover, H2 gas sensing mechanism of TPNC sensors based contact areas and the correlation of energy levels between PANI chains and the titania grains were studied.

Possibilities of gas-phase radio-chromatography application to permanent-gas analysis

International Nuclear Information System (INIS)

Dupuis, M.C.; Charrier, G.; Alba, C.; Massimino, D.

1970-01-01

The gas-phase radio-chromatography technique has been applied to the rapid analysis of permanent gases (H 2 , O 2 , N 2 , A, Kr, Xe, CO, CH 4 ) labelled with radioactive indicators ( 3 H, 37 A, 85 Kr, 133 Xe). After calibration, the components of such a mixture can be identified and their concentrations measured in less than two hours, using a sample volume of from 0.1 to 10 cm 3 . The minimum detectable activity is of the order of 10 -4 μC for each radioactive isotope. The measurements are reproducible to about 2 to 3 per cent. This work has been mainly concerned with the influence of parameters affecting the response of the radioactivity detector (ionization chamber or gas flow proportional counter). The method has very numerous applications both theoretically, for the study of chromatographic phenomena under ideal conditions (infinitesimal concentrations made possible by the use of radioactive tracers), and practically, for rapid and accurate radiochemical analysis of radioactive gas mixtures. (authors) [fr

The 'Shale Gas Revolution'. Hype and Reality

International Nuclear Information System (INIS)

Stevens, P.

2010-09-01

The 'shale gas revolution' - responsible for a huge increase in unconventional gas production in the US over the last couple of years - is creating huge investor uncertainties for international gas markets and renewables and could result in serious gas shortages in 10 years time. This report casts serious doubt over industry confidence in the 'revolution', questioning whether it can spread beyond the US, or indeed be maintained within it, as environmental concerns, high depletion rates and the fear that US circumstances may be impossible to replicate elsewhere, come to the fore. Investor uncertainty will reduce investment in future gas supplies to lower levels than would have happened had the 'shale gas revolution' not hit the headlines. While the markets will eventually solve this problem, rising gas demand and the long lead-in-times on most gas projects are likely to inflict high prices on consumers in the medium term. The uncertainties created by the 'shale gas revolution' are also likely to compound existing investor uncertainty in renewables for power generation in the aftermath of Copenhagen. The serious possibility of cheap, relatively clean gas may threaten investment in more expensive lower carbon technologies.

Graviresponsiveness of surgically altered primary roots of Zea mays

Science.gov (United States)

Maimon, E.; Moore, R.

1991-01-01

We examined the gravitropic responses of surgically altered primary roots of Zea mays to determine the route by which gravitropic inhibitors move from the root tip to the elongating zone. Horizontally oriented roots, from which a 1-mm-wide girdle of epidermis plus 2-10 layers of cortex were removed from the apex of the elongating zone, curve downward. However, curvature occurred only apical to the girdle. Filling the girdle with mucilage-like material transmits curvature beyond the girdle. Vertically oriented roots with a half-girdle' (i.e. the epidermis and 2-10 layers of the cortex removed from half of the circumference of the apex of the elongating zone) curve away from the girdle. Inserting the half-girdle at the base of the elongating zone induces curvature towards the girdle. Filling the half-circumference girdles with mucilage-like material reduced curvature significantly. Stripping the epidermis and outer 2-5 layers of cortex from the terminal 1.5 cm of one side of a primary root induces curvature towards the cut, irrespective of the root's orientation to gravity. This effect is not due to desiccation since treated roots submerged in water also curved towards their cut surface. Coating a root's cut surface with a mucilage-like substance minimizes curvature. These results suggest that the outer cell-layers of the root, especially the epidermis, play an important role in root gravicurvature, and the gravitropic signals emanating from the root tip can move apoplastically through mucilage.

Natural gas market assessment ten years after deregulation

International Nuclear Information System (INIS)

1996-11-01

Changes which have taken place in the Canadian natural gas market in the ten years since the gas market was de-regulated, were reviewed. A 1985 agreement created conditions for a competitive natural gas market. However, the National Energy Board ensured that the pipeline transmission sector of the gas industry would continue to be regulated because of its natural monopoly characteristics. Open non-discriminatory access was to be provided to all shippers on inter-provincial gas pipelines. One objective of this report was to provide the Board with the means of assuring itself that the market was operating in such a way that Canadian requirements for natural gas were being met at fair market prices. The report also provided a review of the major changes in the gas producing and transmission sector, and reviewed developments in gas markets and sales practices. The overall assessment was that the natural gas industry was efficient and responsive to the demands of the marketplace. 5 tabs., 30 figs

Shale Gas Development and Brook Trout: Scaling Best Management Practices to Anticipate Cumulative Effects

Science.gov (United States)

Smith, David; Snyder, Craig D.; Hitt, Nathaniel P.; Young, John A.; Faulkner, Stephen P.

2012-01-01

Shale gas development may involve trade-offs between energy development and benefits provided by natural ecosystems. However, current best management practices (BMPs) focus on mitigating localized ecological degradation. We review evidence for cumulative effects of natural gas development on brook trout (Salvelinus fontinalis) and conclude that BMPs should account for potential watershed-scale effects in addition to localized influences. The challenge is to develop BMPs in the face of uncertainty in the predicted response of brook trout to landscape-scale disturbance caused by gas extraction. We propose a decision-analysis approach to formulating BMPs in the specific case of relatively undisturbed watersheds where there is consensus to maintain brook trout populations during gas development. The decision analysis was informed by existing empirical models that describe brook trout occupancy responses to landscape disturbance and set bounds on the uncertainty in the predicted responses to shale gas development. The decision analysis showed that a high efficiency of gas development (e.g., 1 well pad per square mile and 7 acres per pad) was critical to achieving a win-win solution characterized by maintaining brook trout and maximizing extraction of available gas. This finding was invariant to uncertainty in predicted response of brook trout to watershed-level disturbance. However, as the efficiency of gas development decreased, the optimal BMP depended on the predicted response, and there was considerable potential value in discriminating among predictive models through adaptive management or research. The proposed decision-analysis framework provides an opportunity to anticipate the cumulative effects of shale gas development, account for uncertainty, and inform management decisions at the appropriate spatial scales.

Proposal for data acquisition system of gas chromatograph and natural gas transfer custody via web; Proposta para um sistema de aquisicao de dados de cromatografia e medicao fiscal de gas natural via web

Energy Technology Data Exchange (ETDEWEB)

Santana, Jose Paulo C.; Guimaraes, Marcelo F.; Zeitoune, Rafael J. [PETROBRAS, Rio de Janeiro, RJ (Brazil)

2005-07-01

In this paper, is presented a proposal of a Chromatograph and Transfer Custody Measurement Data Acquisition System through Web, complementary to the SCADA System, responsible for control and monitoring PETROBRAS Gas Pipelines, intended to comply with the requirements of the Gerencias de Qualidade e Medicao (MQD) and Planejamento Integrado da Logistica (PCL) from PETROBRAS Gas e Energia, regarding the evaluation of the quality of the natural gas that is being commercialized, as well as its billing. (author)

Comparing success levels of different neural network structures in extracting discriminative information from the response patterns of a temperature-modulated resistive gas sensor

Science.gov (United States)

Hosseini-Golgoo, S. M.; Bozorgi, H.; Saberkari, A.

2015-06-01

Performances of three neural networks, consisting of a multi-layer perceptron, a radial basis function, and a neuro-fuzzy network with local linear model tree training algorithm, in modeling and extracting discriminative features from the response patterns of a temperature-modulated resistive gas sensor are quantitatively compared. For response pattern recording, a voltage staircase containing five steps each with a 20 s plateau is applied to the micro-heater of the sensor, when 12 different target gases, each at 11 concentration levels, are present. In each test, the hidden layer neuron weights are taken as the discriminatory feature vector of the target gas. These vectors are then mapped to a 3D feature space using linear discriminant analysis. The discriminative information content of the feature vectors are determined by the calculation of the Fisher’s discriminant ratio, affording quantitative comparison among the success rates achieved by the different neural network structures. The results demonstrate a superior discrimination ratio for features extracted from local linear neuro-fuzzy and radial-basis-function networks with recognition rates of 96.27% and 90.74%, respectively.

Comparing success levels of different neural network structures in extracting discriminative information from the response patterns of a temperature-modulated resistive gas sensor

International Nuclear Information System (INIS)

Hosseini-Golgoo, S M; Bozorgi, H; Saberkari, A

2015-01-01

Performances of three neural networks, consisting of a multi-layer perceptron, a radial basis function, and a neuro-fuzzy network with local linear model tree training algorithm, in modeling and extracting discriminative features from the response patterns of a temperature-modulated resistive gas sensor are quantitatively compared. For response pattern recording, a voltage staircase containing five steps each with a 20 s plateau is applied to the micro-heater of the sensor, when 12 different target gases, each at 11 concentration levels, are present. In each test, the hidden layer neuron weights are taken as the discriminatory feature vector of the target gas. These vectors are then mapped to a 3D feature space using linear discriminant analysis. The discriminative information content of the feature vectors are determined by the calculation of the Fisher’s discriminant ratio, affording quantitative comparison among the success rates achieved by the different neural network structures. The results demonstrate a superior discrimination ratio for features extracted from local linear neuro-fuzzy and radial-basis-function networks with recognition rates of 96.27% and 90.74%, respectively. (paper)

Modeling Coma Gas Jets in Comet Hale-Bopp

Science.gov (United States)

Lederer, S. M.; Campins, H.

2001-01-01

We present an analysis of OH, CN, and C2 jets observed in Comet Hale-Bopp. The relative contributions from and composition of the coma gas sources, and the parameters describing the active areas responsible for the gas jets will be discussed. Additional information is contained in the original extended abstract.

Compact permanent magnet H⁺ ECR ion source with pulse gas valve.

Science.gov (United States)

Iwashita, Y; Tongu, H; Fuwa, Y; Ichikawa, M

2016-02-01

Compact H(+) ECR ion source using permanent magnets is under development. Switching the hydrogen gas flow in pulse operations can reduce the gas loads to vacuum evacuation systems. A specially designed piezo gas valve chops the gas flow quickly. A 6 GHz ECR ion source equipped with the piezo gas valve is tested. The gas flow was measured by a fast ion gauge and a few ms response time is obtained.

Akt Kinase-Mediated Checkpoint of cGAS DNA Sensing Pathway

Directory of Open Access Journals (Sweden)

Gil Ju Seo

2015-10-01

Full Text Available Upon DNA stimulation, cyclic GMP-AMP synthase (cGAS synthesizes the second messenger cyclic GMP-AMP (cGAMP that binds to the STING, triggering antiviral interferon-β (IFN-β production. However, it has remained undetermined how hosts regulate cGAS enzymatic activity after the resolution of DNA immunogen. Here, we show that Akt kinase plays a negative role in cGAS-mediated anti-viral immune response. Akt phosphorylated the S291 or S305 residue of the enzymatic domain of mouse or human cGAS, respectively, and this phosphorylation robustly suppressed its enzymatic activity. Consequently, expression of activated Akt led to the reduction of cGAMP and IFN-β production and the increase of herpes simplex virus 1 replication, whereas treatment with Akt inhibitor augmented cGAS-mediated IFN-β production. Furthermore, expression of the phosphorylation-resistant cGAS S291A mutant enhanced IFN-β production upon DNA stimulation, HSV-1 infection, and vaccinia virus infection. Our study identifies an Akt kinase-mediated checkpoint to fine-tune hosts’ immune responses to DNA stimulation.

Negative/positive chemotaxis of a droplet: Dynamic response to a stimulant gas

Science.gov (United States)

Sakuta, Hiroki; Magome, Nobuyuki; Mori, Yoshihito; Yoshikawa, Kenichi

2016-05-01

We report here the repulsive/attractive motion of an oil droplet floating on an aqueous phase caused by the application of a stimulant gas. A cm-sized droplet of oleic acid is repelled by ammonia vapor. In contrast, a droplet of aniline on an aqueous phase moves toward hydrochloric acid as a stimulant. The mechanisms of these characteristic behaviors of oil droplets are discussed in terms of the spatial gradient of the interfacial tension caused by the stimulant gas.

Observed gas hydrate morphologies in marine sediment

Energy Technology Data Exchange (ETDEWEB)

Holland, M.; Schultheiss, P.; Roberts, J.; Druce, M. [Geotek Ltd., Daventry, Northamptonshire (United Kingdom)

2008-07-01

The morphology of gas hydrate in marine sediments determines the basic physical properties of the sediment-hydrate matrix and provides information regarding the formation of gas hydrate deposits, and the nature of the disruption that will occur on dissociation. Small-scale morphology is useful in estimating the concentrations of gas hydrate from geophysical data. It is also important for predicting their response to climate change or commercial production. Many remote techniques for gas hydrate detection and quantification depend on hydrate morphology. In this study, morphology of gas hydrate was examined in HYACINTH pressure cores from recent seagoing expeditions. Visual and infrared observations from non-pressurized cores were also used. The expeditions and pressure core analysis were described in detail. This paper described the difference between two types of gas hydrate morphologies, notably pore-filling and grain-displacing. Last, the paper addressed the impact of hydrate morphology. It was concluded that a detailed morphology of gas hydrate is an essential component for a full understanding of the past, present, and future of any gas hydrate environment. 14 refs., 4 figs.

Gas characterization system operation, maintenance, and calibration plan

International Nuclear Information System (INIS)

Tate, D.D.

1996-01-01

This document details the responsibilities and requirements for operation, maintenance, and calibration of the Gas Characterization Systems (GCS) analytical instrumentation. It further, defines the division of responsibility between the Characterization Monitoring Development organization and Tank Farms Operations

Graphene oxide for gas detection under standard humidity conditions

International Nuclear Information System (INIS)

Donarelli, Maurizio; Prezioso, Stefano; Perrozzi, Francesco; Ottaviano, Luca; Giancaterini, Luca; Cantalini, Carlo; Treossi, Emanuele; Palermo, Vincenzo; Santucci, Sandro

2015-01-01

Graphene oxide (GO) synthesis is the easiest way to functionalize graphene, preserving the high graphene surface to volume ratio. Therefore, GO is a promising candidate for gas sensing applications. In this paper, an easy-to-fabricate and high sensitivity GO-based gas sensor is proposed. The device is fabricated by drop-casting a solution of GO flakes dispersed in water on a prepatterned Si 3 N 4 substrate with 30 μm spaced Pt electrodes. The sensing material has been studied using scanning electron microscopy and x-ray photoelectron spectroscopy. The large lateral dimensions of the flakes (tens of microns) allow single GO flake to bridge adjacent electrodes. The high quality of the synthesized flakes results in the gas sensor high sensitivity to and low detection limit (20 ppb) of NO 2 . The gas sensor response to NO 2 has been studied in various relative humidity environments and it is demonstrated not to be affected by the presence of water vapor. Finally, the gas sensor responses to acetone, toluene, ethanol, and ammonia are reported. (paper)

Response to gravity by Zea mays seedlings. I. Time course of the response

Science.gov (United States)

Bandurski, R. S.; Schulze, A.; Dayanandan, P.; Kaufman, P. B.

1984-01-01

Gravistimulation induces an asymmetric distribution of free indole-3-acetic acid (IAA) in the cortex-epidermis of the Zea mays L. cv 'Stowells Evergreen' mesocotyl within 15 minutes, the shortest time tested. IAA was measured by an isotope dilution method as the pentaflurobenzyl ester. The per cent IAA in the lower half of the mescotyl cortex was 56 to 57% at 15, 30, and 90 minutes after stimulus initiation. Curvature is detectable in the mescotyl within 3 minutes after beginning gravitropic stimulation. The rate of curvature of the mesocotyl increases during the first 60 minutes to maximum of about 30 degrees per hour. Thus, the growth asymmetry continues to increase for 45 minutes after hormone asymmetry is established. Free IAA occurs predominantly in the stele of the mesocotyl whereas esterified IAA is mainly in the mesocotyl cortex-epidermis. This compartmentation may permit determining in which tissue the hormone asymmetry arises. Current data suggest the asymmetry originated in the stele.

cGAS Conducts Micronuclei DNA Surveillance.

Science.gov (United States)

de Oliveira Mann, Carina C; Kranzusch, Philip J

2017-10-01

DNA damage elicits a potent proinflammatory immune response. A collection of four papers now reveals that micronuclear DNA is a new cell intrinsic immunostimulatory molecule, and that accumulation of the immune sensor cyclic GMP-AMP synthase (cGAS) in micronuclei leads to a cell-cycle-dependent proinflammatory response following DNA damage. Copyright © 2017 Elsevier Ltd. All rights reserved.

A Smart Gas Sensor Insensitive to Humidity and Temperature Variations

International Nuclear Information System (INIS)

Hajmirzaheydarali, Mohammadreza; Ghafarinia, Vahid

2011-01-01

The accuracy of the quantitative sensing of volatile organic compounds by chemoresistive gas sensors suffers from the fluctuations in the background atmospheric conditions. This is caused by the drift-like terms introduced in the responses by these instabilities, which should be identified and compensated. Here, a mathematical model is presented for a specific chemoresistive gas sensor, which facilitates these identification and compensation processes. The resistive gas sensor was considered as a multi-input-single-output system. Along with the steady state value of the measured sensor resistance, the ambient humidity and temperature are the inputs to the system, while the concentration level of the target gas is the output. The parameters of the model were calculated based on the experimental database. The model was simulated by the utilization of an artificial neural network. This was connected to the sensor and could deliver the correct contamination level upon receiving the measured gas response, ambient humidity and temperature.

Workshop on Gas Channels

Science.gov (United States)

2013-02-07

Effect of pressure on gas permeability. In Fish … Different channels or splice variants at different depth.  HRE (hypoxia-response elements): which...proteins unexpectedly have HREs . HIF-1.  Shear stress:  expression of NOS  Are different splice variants used under different conditions?  Size

Determination of dynamic variations in the optical properties of graphene oxide in response to gas exposure based on thin-film interference.

Science.gov (United States)

Tabassum, Shawana; Dong, Liang; Kumar, Ratnesh

2018-03-05

We present an effective yet simple approach to study the dynamic variations in optical properties (such as the refractive index (RI)) of graphene oxide (GO) when exposed to gases in the visible spectral region, using the thin-film interference method. The dynamic variations in the complex refractive index of GO in response to exposure to a gas is an important factor affecting the performance of GO-based gas sensors. In contrast to the conventional ellipsometry, this method alleviates the need of selecting a dispersion model from among a list of model choices, which is limiting if an applicable model is not known a priori. In addition, the method used is computationally simpler, and does not need to employ any functional approximations. Further advantage over ellipsometry is that no bulky optics is required, and as a result it can be easily integrated into the sensing system, thereby allowing the reliable, simple, and dynamic evaluation of the optical performance of any GO-based gas sensor. In addition, the derived values of the dynamically changing RI values of the GO layer obtained from the method we have employed are corroborated by comparing with the values obtained from ellipsometry.

Canadian natural gas market dynamics and pricing : an update

International Nuclear Information System (INIS)

2002-10-01

This energy market assessment (EMA) report discusses natural gas price formation and describes the current functioning of regional gas markets in Canada. This EMA also describes the factors affecting the price of natural gas in Canada and examines natural gas markets on a region-by region basis. It is shown that as part of an integrated North American market, prices of natural gas in Canada reflect supply and demand factors in both Canada and the United States. During the low oil price period of 1997/1998, high demand for natural gas outpaced the supply because of low drilling and production activity by producers. In response to the increased demand and lower levels of supply, the price of natural gas increased significantly in 1999 and 2000. This was followed by a period of market adjustment. The importance of electronic trading systems for enhancing price discovery was also discussed with reference to how spot and futures markets allow market participants to manage price volatility. It was determined that Canadians have had access to natural gas on terms and conditions equal to export customers, and at equal pricing. In early November 2000, natural gas prices in North American began to rise due to low levels of natural gas in storage. The price shocks were felt unevenly across the North American market. In response to the high prices, consumers conserved energy use, and many industrial users switched to cheaper fuels. By the spring 2001, demand continued to decrease at a time when production was high. These factors contributed to the downward pressure on gas prices. This EMA discusses the structure of market transactions and market adjustment mechanisms. It is presented in the context of the approaching 2002/2003 winter season where the tightening between natural gas supply and demand is expected to result in price volatility. 28 figs

Nanostructured ZrO2 Thick Film Resistors as H2-Gas Sensors Operable at Room Temperature

Directory of Open Access Journals (Sweden)

K. M. GARADKAR

2009-11-01

Full Text Available Nanostructured ZrO2 powder was synthesized by microwave assisted sol-gel method. The material was characterized by XRD and SEM techniques. X-Ray diffraction studies confirm that a combination of tetragonal and monoclinic zirconia nanoparticles is obtained by using microwave-assisted method. The nanopowder was calcined at an optimized temperature of 400 °C for 3 h. The prepared powder had crystalline size about 25 nm. Thick films of synthesized ZrO2 powder were prepared by screen printing technique. The gas sensing performances of these films for various gases were tested. Films showed highest response to H2 (50 ppm gas at room temperature with poor responses to others (1000 ppm. The quick response and fast recovery are the main features of this sensor. The effects of microstructure, operating temperature and gas concentration on the gas response, selectivity, response time and recovery time of the sensor in the presence of H2 gas and others were studied and discussed.

Environmental requirements for oil and gas operations in Saskatchewan

International Nuclear Information System (INIS)

Nystuen, L.J.

1997-01-01

The administration and regulation of environmental issues regarding the oil and gas industry in Saskatchewan were discussed. The political and cultural differences in Saskatchewan that make environmental processes distinct from its neighbouring jurisdictions were described. The following Saskatchewan legislation deals with environmental requirements: Environmental Management and Protection Act, Environmental Assessment Act, Oil and Gas Conservation Act, Wildlife Habitat Protection Act, Clean Air Act, Planning and Development Act, Forest Act, Water Corporation Act, Heritage Property Act, and Parks Act. The Saskatchewan Department of Energy and Mines (SEM) is the primary regulator of the upstream oil and gas industry. It regulates the construction, operation, reporting and abandonment requirements for oilfield operations. SEM also manages crude oil prior to refining and manages the wastes contaminated with crude oil. Provisions of the relevant Acts regarding drilling in environmentally sensitive areas, flaring requirements, transporting and disposing of oilfield wastes, road-building, operating restrictions, emergency response plans, spill clean-up responsibilities, well abandonment and site reclamation responsibilities were discussed. 8 refs., 2 tabs

New directions in gas processing

International Nuclear Information System (INIS)

Anon.

1996-01-01

Papers presented at the Insight conference held on January 30, 1996 in Calgary, Alberta, were contained in this volume. The conference was devoted to a discussion of new directions in the gas processing business, the changing business environment, new processing technologies, and means by which current facilities agreements can be adapted to the new commercial reality. High operating costs which have resulted in the downsizing and restructuring of the industry, and partnering with a third party in the gathering and processing operations, with apparently beneficial result both to plant owners, as well to third party processors, received the most attention. The relationship between the gas processor and the gas producer as they relate to the Petroleum Joint Venture Association (PJVA) Gas Processing Agreement, which defines the obligations of third parties, was the center of discussion. Regulatory changes and the industry's response to the changes was also on the agenda. Refs., tabs., figs

PP and PS seismic response from fractured tight gas reservoirs: a case study

International Nuclear Information System (INIS)

Jianming, Tang; Shaonan, Zhang; Li, Xiang-Yang

2008-01-01

In this paper, we present an example of using PP and PS converted-wave data recorded by digital micro-eletro-mechanical-systems (MEMS) to evaluate a fractured tight gas reservoir from the Xinchang gas field in Sichuan, China. For this, we analyse the variations in converted shear-wave splitting, Vp/Vs ratio and PP and PS impedance, as well as other attributes based on absorption and velocity dispersion. The reservoir formation is tight sandstone, buried at a depth of about 5000 m, and the converted-wave data reveal significant shear-wave splitting over the reservoir formation. We utilize a rotation technique to extract the shear-wave polarization and time delay from the data, and a small-window correlation method to build time-delay spectra that allow the generation of a time-delay section. At the reservoir formation, the shear-wave time delay is measured at 20 ms, about 15% shear-wave anisotropy, correlating with the known gas reservoirs. Furthermore, the splitting anomalies are consistent with the characteristics of other attributes such as Vp/Vs ratio and P- and S-wave acoustic and elastic impedance. The P-wave shows consistent low impedance over the reservoir formation, whilst the S-wave impedance shows relatively high impedance. The calculated gas indicator based on absorption and velocity dispersion yields a high correlation with the gas bearing formations. This confirms the benefit of multicomponent seismic data from digital MEMS sensors

Decision in the matter of a generic hearing in respect to market issues and conduct related to the sale of gas and customer services in the natural gas industry in New Brunswick

International Nuclear Information System (INIS)

2003-01-01

In response to changes in the Gas Distribution Act and the Gas Distributor Marketing Regulation, the New Brunswick Board of Commissioners of Public Utilities (Board), issued an order in June 2003 for a generic hearing regarding the sale of gas and customer services in the natural gas industry in New Brunswick. The purpose of the hearing was to have an open discussion among intervenors regarding several issues, such as whether the Code of Conduct provides fair and adequate rules for marketers; should Enbridge Gas New Brunswick (EGNB) be required to follow rules similar to the Code of Conduct; the requirements surrounding letters of credit; the Board's decision on Rules and Regulations regarding the billing conduct of gas distributors and marketers; the information that should be provided by a gas marketer or a distributor to the customer before the customer enters into an agreement for the supply of gas; the need for information on price volatility; the need for EGNB to notify potential customers of all possible suppliers of gas; the removal of automatic renewal clauses from gas retailers' contracts; how the Board should determine if prices are reasonably and sufficiently competitive; financial reporting requirements; the role of the Board in response to customer complaints regarding the sale of gas by a distributor; and, the Board's action regarding Enbridge Atlantic's plan to exit the New Brunswick market. This report provided the response to these issues by 10 intervenors

Spectral Decomposition and Other Seismic Attributes for Gas Hydrate Prospecting

Energy Technology Data Exchange (ETDEWEB)

McConnell, Dan

2018-02-25

Studying the sediments at the base of gas hydrate stability is ideal for determining the seismic response to gas hydrate saturation. First, assuming gas migration to the shallow section, this area is more likely to have concentrated gas hydrate because it encompasses the zone in which upward moving buoyant gas transitions to form immobile gas hydrate deposits. Second, this zone is interesting because these areas have the potential to show a hydrate filled zone and a gas filled zone within the same sediments. Third, the fundamental measurement within seismic data is impedance contrasts between velocity*density layers. High saturation gas hydrates and free gas inhabit opposite ends of these measurements making the study of this zone ideal for investigating the seismic characteristics of gas hydrate and, hence, the investigation of other seismic attributes that may indicate gas hydrate fill.

Gas Sensing Properties of Pure and Cr Activated WO3 Thick Film Resistors

Directory of Open Access Journals (Sweden)

V. B. GAIKWAD

2010-09-01

Full Text Available Thick films of WO3 (Tungsten Oxide were prepared by screen-printing techniques. The surfaces of the films were modified by dipping them into an aqueous solution of Chromium Oxide (CrO3 for different intervals of time, followed by firing at 550 oC for 30 min. The gas sensing performance of the pure and Cr2O3-modified films was tested for various gases at different temperatures. The unmodified films showed response to H2S, ethanol and cigar smoke. However Cr2O3- modified films suppresses gas sensing response to all gases except H2S. The surface modification, using dipping process, altered the adsorbate-adsorbent interactions, which gave the specific selectivity and enhanced sensitivity to H2S gas. The gas response, selectivity, thermal stability and recovery time of the sensor were measured and presented. The role played by surface chromium species to improve gas sensing performance is discussed.

Transient dynamic crack propagation in gas pressurised pipelines

International Nuclear Information System (INIS)

Caldis, E.S.; Owen, D.R.J.; Taylor, C.

1983-01-01

The prime limitation of dynamic fracture analysis is the lack of a fundamental crack advance theory which can be easily and economically adopted for use with numerical models. The necessity for the inclusion of inertia effects in the solution of certain problem classes is now evident, but most transient dynamic fracture models considered to date include (of necessity) some intuitive/empirical parameters with a frequent need of a priori knowledge of experimental solutions. The particular problem considered in this study is Mode I transient dynamic crack propagation in gas pressurised pipelines. The steel pipe is modelled using thin shell Semiloof finite elements and its transient response is coupled to a one-dimensional finite element model of the compressible gas equations, incorporating a lateral gas flow parameter. The pipe is governed by the usual dynamic equilibrium equation which is discretised in the time domain by a central difference explicit algorithm. The compressible gas response is modelled by the Continuity and Momentum equations and time discretisation is performed by means of a fully backward difference scheme in time. (orig./GL)

Rapid and selective detection of acetone using hierarchical ZnO gas sensor for hazardous odor markers application.

Science.gov (United States)

Jia, Qianqian; Ji, Huiming; Zhang, Ying; Chen, Yalu; Sun, Xiaohong; Jin, Zhengguo

2014-07-15

Hierarchical nanostructured ZnO dandelion-like spheres were synthesized via solvothermal reaction at 200°C for 4h. The products were pure hexagonal ZnO with large exposure of (002) polar facet. Side-heating gas sensor based on hierarchical ZnO spheres was prepared to evaluate the acetone gas sensing properties. The detection limit to acetone for the ZnO sensor is 0.25ppm. The response (Ra/Rg) toward 100ppm acetone was 33 operated at 230°C and the response time was as short as 3s. The sensor exhibited remarkable acetone selectivity with negligible response toward other hazardous gases and water vapor. The high proportion of electron depletion region and oxygen vacancies contributed to high gas response sensitivity. The hollow and porous structure of dandelion-like ZnO spheres facilitated the diffusion of gas molecules, leading to a rapid response speed. The largely exposed (002) polar facets could adsorb acetone gas molecules easily and efficiently, resulting in a rapid response speed and good selectivity of hierarchical ZnO spheres gas sensor at low operating temperature. Copyright © 2014 Elsevier B.V. All rights reserved.

A Rapid Process for Fabricating Gas Sensors

Directory of Open Access Journals (Sweden)

Chun-Ching Hsiao

2014-07-01

Full Text Available Zinc oxide (ZnO is a low-toxicity and environmentally-friendly material applied on devices, sensors or actuators for “green” usage. A porous ZnO film deposited by a rapid process of aerosol deposition (AD was employed as the gas-sensitive material in a CO gas sensor to reduce both manufacturing cost and time, and to further extend the AD application for a large-scale production. The relative resistance change (△R/R of the ZnO gas sensor was used for gas measurement. The fabricated ZnO gas sensors were measured with operating temperatures ranging from 110 °C to 180 °C, and CO concentrations ranging from 100 ppm to 1000 ppm. The sensitivity and the response time presented good performance at increasing operating temperatures and CO concentrations. AD was successfully for applied for making ZnO gas sensors with great potential for achieving high deposition rates at low deposition temperatures, large-scale production and low cost.

From comic relief to real understanding; how intestinal gas causes symptoms.

LENUS (Irish Health Repository)

Quigley, E M M

2012-02-03

Gas content and transit appear to conspire with the motor and sensory responses of the gut to produce gas related symptoms, both in normal individuals and especially in patients with irritable bowel syndrome (IBS). In relation to gas in IBS, two questions need to be addressed: do IBS patients produce more gas and what are the relationships between intestinal gas and symptoms? The balance of evidence seems to indicate that distension is a real phenomenon in IBS and that such distension accurately reflects gas content. More problematic is extrapolation of the observations relating symptoms to gas transit and retention.

Natural gas contracts in efficient portfolios

Energy Technology Data Exchange (ETDEWEB)

Sutherland, R.J.

1994-12-01

This report addresses the {open_quotes}contracts portfolio{close_quotes} issue of natural gas contracts in support of the Domestic Natural Gas and Oil Initiative (DGOI) published by the U.S. Department of Energy in 1994. The analysis is a result of a collaborative effort with the Public Service Commission of the State of Maryland to consider {open_quotes}reforms that enhance the industry`s competitiveness{close_quotes}. The initial focus of our collaborative effort was on gas purchasing and contract portfolios; however, it became apparent that efficient contracting to purchase and use gas requires a broader consideration of regulatory reform. Efficient portfolios are obtained when the holder of the portfolio is affected by and is responsible for the performance of the portfolio. Natural gas distribution companies may prefer a diversity of contracts, but the efficient use of gas requires that the local distribution company be held accountable for its own purchases. Ultimate customers are affected by their own portfolios, which they manage efficiently by making their own choices. The objectives of the DGOI, particularly the efficient use of gas, can be achieved when customers have access to suppliers of gas and energy services under an improved regulatory framework. The evolution of the natural gas market during the last 15 years is described to account for the changing preferences toward gas contracts. Long-term contracts for natural gas were prevalent before the early 1980s, primarily because gas producers had few options other than to sell to a single pipeline company, and this pipeline company, in turn, was the only seller to a gas distribution company.

Natural gas monthly, September 1991. [Contains glossary

Energy Technology Data Exchange (ETDEWEB)

1991-10-18

The Natural Gas Monthly highlights activities, events, and analyses of interest to public and private sector organizations associated with the natural gas industry. Volume and price data are presented each month for natural gas production distribution consumption, and interstate pipeline activities. Producer-related activities and underground storage data are also reported. From time to time, the NGM features articles designed to assist readers in using and interpreting natural gas information. The data in this publication are collected on surveys conducted by the EIA to fulfill its responsibilities for gathering and reporting energy data. Some of the data are collected under the authority of the Federal Energy Regulatory Commission (FERC), an independent commission within the DOE, which has jurisdiction primarily in the regulation of electric utilities and the interstate natural gas industry. Geographic coverage is the 50 States and the District of Columbia.

Greenhouse gas emissions in salt marshes and their response to nitrogen loading

Science.gov (United States)

Tang, J.; Moseman-Valtierra, S.; Kroeger, K. D.; Morkeski, K.; Carey, J.

2015-12-01

Salt marshes play an important role in global and regional carbon and nitrogen cycling. Anthropogenic nitrogen loading may alter greenhouse gas (GHG, including CO2, CH4, and N2O) emissions and carbon sequestration in salt marshes. We measured GHG emissions biweekly for two growing seasons across a nitrogen-loading gradient of four Spartina salt marshes in Waquoit Bay, Massachusetts. In addition, we conducted nitrogen addition experiments in a pristine marsh by adding low and high nitrate bi-weekly during the summer. The GHG flux measurements were made in situ with a state-of-the-art mobile gas measurement system using the cavity ring down technology that consists of a CO2/CH4 analyzer (Picarro) and an N2O/CO analyzer (Los Gatos). We observed strong seasonal variations in greenhouse gas emissions. The differences in gas emissions across the nitrogen gradient (between 1 and 10 gN m-2y-1) were not significant, but strong pulse emissions of N2O were observed after nitrogen was artificially added to the marsh. We found that the studied salt marsh was a significant carbon sink (NEP ~ 380 gC m-2y-1). CH4 fluxes are 3 orders of magnitude less than CO2 fluxes in the salt marsh. Carbon fluxes are driven by light, salinity, tide, and temperature. We conclude that restoration or conservation of this carbon sink has a significant social benefit for carbon credit.

Working under the PJVA gas processing agreement

International Nuclear Information System (INIS)

Collins, S.

1996-01-01

The trend in the natural gas industry is towards custom processing. New gas reserves tend to be smaller and in tighter reservoirs than in the past. This has resulted in plants having processing and transportation capacity available to be leased to third parties. Major plant operators and owners are finding themselves in the business of custom processing in a more focused way. Operators recognize that the dilution of operating costs can result in significant benefits to the plant owners as well as the third party processor. The relationship between the gas processor and the gas producer as they relate to the Petroleum Joint Venture Association (PJVA) Gas Processing Agreement were discussed. Details of the standard agreement that clearly defines the responsibilities of the third party producer and the processor were explained. In addition to outlining obligations of the parties, it also provides a framework for fee negotiation. It was concluded that third party processing can lower facility operating costs, extend facility life, and keep Canadian gas more competitive in holding its own in North American gas markets

Hazard assessments of double-shell flammable gas tanks

International Nuclear Information System (INIS)

Fox, G.L.; Stepnewski, D.D.

1994-01-01

This report is the fourth in a series of hazard assessments performed on the double-shell flammable gas watch list tanks. This report focuses on hazards associated with the double-shell watch list tanks (101-AW, 103-AN, 104-AN, and 105-AN). While a similar assessment has already been performed for tank 103-SY, it is also included here to incorporate a more representative slurry gas mixture and provide a consistent basis for comparing results for all the flammable gas tanks. This report is intended to provide an in-depth assessment by considering the details of the gas release event and slurry gas mixing as the gas is released from the waste. The consequences of postulated gas ignition are evaluated using a plume burn model and updated ignition frequency predictions. Tank pressurization which results from a gas burn, along with the structural response, is also considered. The report is intended to support the safety basis for work activities in flammable gas tanks by showing margins to safety limits that are available in the design and procedures

Microbial activities in soil near natural gas leaks

Energy Technology Data Exchange (ETDEWEB)

Adamse, A D; Hoeks, J; de Bont, J A.M.; van Kessel, J F

1972-01-01

From the present experiments it may be concluded that in the surroundings of natural gas leaks, methane, ethane and possibly some other components of the natural gas are oxidized by microbial activities as long as oxygen is available. This is demonstrated by an increased oxygen consumption and carbon dioxide production, as well as by increased numbers of different types of bacteria. The resulting deficiency of oxygen, the excess of carbon dioxide, and perhaps the formation of inhibitory amounts of ethylene, are considered to be mainly responsible for the death of trees near natural gas leaks. Also the long period of time needed by the soil to recover, may be due to prolonged microbial activities, as well as to the presence of e.g. ethylene. The present experiments suggest that especially methane-oxidizing bacteria of the Methylosinus trichosporium type were present in predominating numbers and consequently have mainly been responsible for the increased oxygen consumption. However, some fungi oxidizing components of natural gas, including methane and ethane may also have contributed to the increased microbial activities in the soil. The same will be true of a possible secondary microflora on products derived from microorganisms oxidizing natural gas components. 12 references, 9 figures, 7 tables.

Leaf age affects the responses of foliar injury and gas exchange to tropospheric ozone in Prunus serotina seedlings

International Nuclear Information System (INIS)

Zhang Jianwei; Schaub, Marcus; Ferdinand, Jonathan A.; Skelly, John M.; Steiner, Kim C.; Savage, James E.

2010-01-01

We investigated the effect of leaf age on the response of net photosynthesis (A), stomatal conductance (g wv ), foliar injury, and leaf nitrogen concentration (N L ) to tropospheric ozone (O 3 ) on Prunus serotina seedlings grown in open-plots (AA) and open-top chambers, supplied with either carbon-filtered or non-filtered air. We found significant variation in A, g wv , foliar injury, and N L (P 3 treatments. Seedlings in AA showed the highest A and g wv due to relatively low vapor pressure deficit (VPD). Older leaves showed significantly lower A, g wv , N L , and higher foliar injury (P wv , and foliar injury to O 3 . Both VPD and N L had a strong influence on leaf gas exchange. Foliar O 3 -induced injury appeared when cumulative O 3 uptake reached 8-12 mmol m -2 , depending on soil water availability. The mechanistic assessment of O 3 -induced injury is a valuable approach for a biologically relevant O 3 risk assessment for forest trees. - Ozone effects on symptom development and leaf gas exchange interacted with leaf age and N-content on black cherry seedlings.

The mode of lymphoblastoid cell death in response to gas phase cigarette smoke is dose-dependent

Directory of Open Access Journals (Sweden)

Baltatzis George E

2009-09-01

Full Text Available Abstract Background Cigarette smoke (CS is the main cause in the development of chronic obstructive pulmonary disease (COPD, the pathogenesis of which is related to an extended inflammatory response. In this study, we investigated the effect of low and high doses of gas phase cigarette smoke (GPS on cultured lymphocyte progenitor cells, using techniques to assess cell viability and to elucidate whether cells die of apoptosis or necrosis upon exposure to different doses of GPS. Methods In our approach we utilised a newly-established system of exposure of cells to GPS that is highly controlled, accurately reproducible and simulates CS dosage and kinetics that take place in the smokers' lung. This system was used to study the mode of cell death upon exposure to GPS in conjunction with a range of techniques widely used for cell death studies such as Annexin V staining, activation of caspase -3, cytoplasmic release of cytochrome C, loss of mitochondrial membrane potential and DNA fragmentation. Results Low doses of GPS induced specific apoptotic indexes in CCRF-CEM cells. Specifically, cytochrome C release and cleaved caspase-3 were detected by immunofluorescence, upon treatment with 1-3 puffs GPS. At 4 h post-exposure, caspase-3 activation was observed in western blot analysis, showing a decreasing pattern as GPS doses increased. Concomitant with this behaviour, a dose-dependent change in Δψm depolarization was monitored by flow cytometry 2 h post-exposure, while at 4 h Δψm collapse was observed at the higher doses, indicative of a shift to a necrotic demise. A reduction in DNA fragmentation events produced by 5 puffs GPS as compared to those provoked by 3 puffs GPS, also pointed towards a necrotic response at the higher dose of GPS. Conclusion Collectively, our results support that at low doses gas phase cigarette smoke induces apoptosis in cultured T-lymphocytes, whereas at high doses GPS leads to necrotic death, by-passing the characteristic

Multi-level modelling of the response of the ultraminiature proportional counter: gas gain phenomena and pulse height spectra

International Nuclear Information System (INIS)

Olko, P.; Moutarde, C.; Segur, P.

1995-01-01

The ultraminiature proportional counters, UMC, unique radiation detectors for monitoring high intensity therapy fields, designed by Kliauga and operated at Columbia University (USA), have yielded a number of pulse height distributions for photons, neutrons and ions at simulated diameters of 5-50 nm. Monte Carlo calculations of the gas gain in such a counter questioned the possibility of achieving proportionally at such low simulated diameters. The response of the UMC has now been modelled taking into account both fluctuations of energy deposited in the counter volume and its calculated gas gain. Energy deposition was calculated using the MOCA-14, MOCA-8 and TRION codes, whereby distributions of ionisations d(j) after irradiations with 137 Cs, 15 MeV neutrons and 7 MeV.amu -1 deuterons were obtained. Monte Carlo calculations of electron avalanches in UMC show that the size of the single-electron avalanche P(n) reaching the anode depends strongly on the location of the primary ionisation within the counter volume. Distributions of the size of electron avalanches for higher numbers of primary ionisations, P *j (n), were obtained by successive convolutions of P(n). Finally, the counter response was obtained by weighting P *j (n) over d(j) distributions. On comparing the measured and calculated spectra it was concluded that the previously proposed single-electron peak calibration method might not be valid for the UMC due to the excessive width and overlap of electron avalanche distributions. Better agreement between the measured and calculated spectra is found if broader electron avalanche distributions than those used in the present calculations, are assumed. (author)

Approaching the millennium - strategies for the gas buyers

International Nuclear Information System (INIS)

Holder, J.; Kelton, F.

1998-01-01

An overview of what is in store for gas purchasing in Ontario's new deregulated market was presented. Basically, responsibilities will shift from the utility to market players. The impact of this shift on marketers, on end-users and on the utility were assessed. In the new millennium, Consumers Gas, which is Canada's largest and oldest natural gas distributor, will be operating under a new name, Enbridge. The company will focus on developing marketing programs to position natural gas as the number one fuel choice for residential, commercial, apartments, vehicles, cogeneration and industrial markets. The evolution of the 200 customer market model( i.e. large volume customers, gas marketers, commercial customers and residential customers as a group), what each of these groups want from Enbridge, and what Enbridge can deliver as the wholesale provider of natural gas delivery services rounded out the discussion. figs

Rosneftegazstroy - Russia's premier oil and gas contractor

International Nuclear Information System (INIS)

Anon.

1996-01-01

This special Petroleum Economist Sponsored Supplement looks at the present condition and future prospects of the Russian oil and gas industry. Russia's chief oil and gas contractor, Rosneftegazstroy, a joint stock company formed in 1991, took over from the former Soviet Union's Ministry of Oil and Gas Construction and from Neftegazstroy, the State concern. Responsible for the exploration and exploitation of the country's huge oil and gas reserves, Rosneftegazstroy has a mammoth task ahead to modernize and create an adequate infrastructure for its new commercial basis. Its foreign investment projects are described and plans for rebuilding and new developments are discussed. Russia's fuel and energy industries now show clear signs of increasing activity, amid a backdrop of falling production overall. (UK)

Active mems microbeam device for gas detection

KAUST Repository

Bouchaala, Adam M.

2017-10-05

Sensors and active switches for applications in gas detection and other fields are described. The devices are based on the softening and hardening nonlinear response behaviors of microelectromechanical systems (MEMS) clamped-clamped microbeams. In that context, embodiments of gas-triggered MEMS microbeam sensors and switches are described. The microbeam devices can be coated with a Metal-Organic Framework to achieve high sensitivity. For gas sensing, an amplitude-based tracking algorithm can be used to quantify an amount of gas captured by the devices according to frequency shift. Noise analysis is also conducted according to the embodiments, which shows that the microbeam devices have high stability against thermal noise. The microbeam devices are also suitable for the generation of binary sensing information for alarming, for example.

High School Forum. The Solution: "Derivation of the Ideal Gas Law."

Science.gov (United States)

Herron, J. Dudley, Ed.

1980-01-01

Presents responses to an earlier report concerning a procedure for the derivation of the Ideal Gas Law from Charles', Boyle's, and other gas laws. Logic errors and solutions that work are discussed. (CS)

Sympathoadrenal, cardiovascular and blood gas responses to highly selective mu and delta opioid peptides.

Science.gov (United States)

Kiritsy-Roy, J A; Marson, L; Van Loon, G R

1989-12-01

The relative importance of mu and delta opioid receptors in brain regulation of sympathoadrenal, cardiovascular and respiratory function was investigated using highly selective mu and delta opioid peptide analogs. Groups of conscious rats received i.c.v. injections of either the mu-selective agonist, [D-Ala2, MePhe4, Gly-ol5]enkephalin (DAMGO) or the delta-selective agonist, [D-Pen2, D-Pen5]enkephalin (DPDPE). Blood pressure and heart rate were recorded continuously via a chronic catheter in the carotid artery, and arterial blood samples were taken at intervals through the same catheter for determination of blood pH, pCO2, pO2 and plasma catecholamine concentrations. Both DAMGO and DPDPE increased plasma catecholamine levels and blood pressure in a dose-related manner. The slopes of the dose-response lines were parallel, but the delta compound was about 250 times less potent than DAMGO. Only the highest dose of 5 nmol of DAMGO caused a significant bradycardia, mediated by parasympathetic (vagal) activation. DAMGO and DPDPE also induced dose-dependent acidosis, with DAMGO again being much more potent than DPDPE. The effects of both DAMGO and DPDPE on plasma catecholamines, blood pressure and blood gases were antagonized by a mu-selective dose of naloxone (0.4 mg/kg i.a.). Intracerebroventricular administration of the delta-selective antagonist, ICI 174,864, only partially attenuated sympathoadrenal and blood gas responses to DAMGO or DPDPE. The pressor responses to DAMGO or DPDPE were resistant to antagonism by ICI 174,864. These results indicate that brain opioid receptors regulating autonomic outflow, cardiovascular and respiratory function are mainly of the mu type, although a delta opioid system may contribute to sympathoadrenal and respiratory effects of opioids.

Akt Kinase-Mediated Checkpoint of cGAS DNA Sensing Pathway.

Science.gov (United States)

Seo, Gil Ju; Yang, Aerin; Tan, Brandon; Kim, Sungyoon; Liang, Qiming; Choi, Younho; Yuan, Weiming; Feng, Pinghui; Park, Hee-Sung; Jung, Jae U

2015-10-13

Upon DNA stimulation, cyclic GMP-AMP synthase (cGAS) synthesizes the second messenger cyclic GMP-AMP (cGAMP) that binds to the STING, triggering antiviral interferon-β (IFN-β) production. However, it has remained undetermined how hosts regulate cGAS enzymatic activity after the resolution of DNA immunogen. Here, we show that Akt kinase plays a negative role in cGAS-mediated anti-viral immune response. Akt phosphorylated the S291 or S305 residue of the enzymatic domain of mouse or human cGAS, respectively, and this phosphorylation robustly suppressed its enzymatic activity. Consequently, expression of activated Akt led to the reduction of cGAMP and IFN-β production and the increase of herpes simplex virus 1 replication, whereas treatment with Akt inhibitor augmented cGAS-mediated IFN-β production. Furthermore, expression of the phosphorylation-resistant cGAS S291A mutant enhanced IFN-β production upon DNA stimulation, HSV-1 infection, and vaccinia virus infection. Our study identifies an Akt kinase-mediated checkpoint to fine-tune hosts' immune responses to DNA stimulation. Copyright © 2015 The Authors. Published by Elsevier Inc. All rights reserved.

Self-Test Procedures for Gas Sensors Embedded in Microreactor Systems

Science.gov (United States)

Helwig, Andreas; Hackner, Angelika; Zappa, Dario; Sberveglieri, Giorgio

2018-01-01

Metal oxide (MOX) gas sensors sensitively respond to a wide variety of combustible, explosive and poisonous gases. However, due to the lack of a built-in self-test capability, MOX gas sensors have not yet been able to penetrate safety-critical applications. In the present work we report on gas sensing experiments performed on MOX gas sensors embedded in ceramic micro-reaction chambers. With the help of an external micro-pump, such systems can be operated in a periodic manner alternating between flow and no-flow conditions, thus allowing repetitive measurements of the sensor resistances under clean air, R0, and under gas exposure, Rgas, to be obtained, even under field conditions. With these pairs of resistance values, eventual drifts in the sensor baseline resistance can be detected and drift-corrected values of the relative resistance response Resp=(R0−Rgas)/R0 can be determined. Residual poisoning-induced changes in the relative resistance response can be detected by reference to humidity measurements taken with room-temperature-operated capacitive humidity sensors which are insensitive to the poisoning processes operative on heated MOX gas sensors. PMID:29401673

Self-Test Procedures for Gas Sensors Embedded in Microreactor Systems.

Science.gov (United States)

Helwig, Andreas; Hackner, Angelika; Müller, Gerhard; Zappa, Dario; Sberveglieri, Giorgio

2018-02-03

Metal oxide (MOX) gas sensors sensitively respond to a wide variety of combustible, explosive and poisonous gases. However, due to the lack of a built-in self-test capability, MOX gas sensors have not yet been able to penetrate safety-critical applications. In the present work we report on gas sensing experiments performed on MOX gas sensors embedded in ceramic micro-reaction chambers. With the help of an external micro-pump, such systems can be operated in a periodic manner alternating between flow and no-flow conditions, thus allowing repetitive measurements of the sensor resistances under clean air, R 0 , and under gas exposure, R g a s , to be obtained, even under field conditions. With these pairs of resistance values, eventual drifts in the sensor baseline resistance can be detected and drift-corrected values of the relative resistance response R e s p = ( R 0 - R g a s ) / R 0 can be determined. Residual poisoning-induced changes in the relative resistance response can be detected by reference to humidity measurements taken with room-temperature-operated capacitive humidity sensors which are insensitive to the poisoning processes operative on heated MOX gas sensors.

Individual hollow and mesoporous aero-graphitic microtube based devices for gas sensing applications

Science.gov (United States)

Lupan, Oleg; Postica, Vasile; Marx, Janik; Mecklenburg, Matthias; Mishra, Yogendra K.; Schulte, Karl; Fiedler, Bodo; Adelung, Rainer

2017-06-01

In this work, individual hollow and mesoporous graphitic microtubes were integrated into electronic devices using a FIB/SEM system and were investigated as gas and vapor sensors by applying different bias voltages (in the range of 10 mV-1 V). By increasing the bias voltage, a slight current enhancement is observed, which is mainly attributed to the self-heating effect. A different behavior of ammonia NH3 vapor sensing by increasing the applied bias voltage for hollow and mesoporous microtubes with diameters down to 300 nm is reported. In the case of the hollow microtube, an increase in the response was observed, while a reverse effect has been noticed for the mesoporous microtube. It might be explained on the basis of the higher specific surface area (SSA) of the mesoporous microtube compared to the hollow one. Thus, at room temperature when the surface chemical reaction rate (k) prevails on the gas diffusion rate (DK) the structures with a larger SSA possess a higher response. By increasing the bias voltage, i.e., the overall temperature of the structure, DK becomes a limiting step in the gas response. Therefore, at higher bias voltages the larger pores will facilitate an enhanced gas diffusion, i.e., a higher gas response. The present study demonstrates the importance of the material porosity towards gas sensing applications.

Suppressive oligodeoxynucleotides containing TTAGGG motifs inhibit cGAS activation in human monocytes.

Science.gov (United States)

Steinhagen, Folkert; Zillinger, Thomas; Peukert, Konrad; Fox, Mario; Thudium, Marcus; Barchet, Winfried; Putensen, Christian; Klinman, Dennis; Latz, Eicke; Bode, Christian

2018-04-01

Type I interferon (IFN) is a critical mediator of autoimmune diseases such as systemic lupus erythematosus (SLE) and Aicardi-Goutières Syndrome (AGS). The recently discovered cyclic-GMP-AMP (cGAMP) synthase (cGAS) induces the production of type I IFN in response to cytosolic DNA and is potentially linked to SLE and AGS. Suppressive oligodeoxynucleotides (ODN) containing repetitive TTAGGG motifs present in mammalian telomeres have proven useful in the treatment of autoimmune diseases including SLE. In this study, we demonstrate that the suppressive ODN A151 effectively inhibits activation of cGAS in response to cytosolic DNA, thereby inhibiting type I IFN production by human monocytes. In addition, A151 abrogated cGAS activation in response to endogenous accumulation of DNA using TREX1-deficient monocytes. We demonstrate that A151 prevents cGAS activation in a manner that is competitive with DNA. This suppressive activity of A151 was dependent on both telomeric sequence and phosphorothioate backbone. To our knowledge this report presents the first cGAS inhibitor capable of blocking self-DNA. Collectively, these findings might lead to the development of new therapeutics against IFN-driven pathologies due to cGAS activation. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Onsite gas storage for industrial customers

International Nuclear Information System (INIS)

Shikari, Y.A.

1990-01-01

The changing pattern of industrial gas marketing in the United States and other countries has placed new pressures on industrial users to assume responsibility for assuring their own supply. Technological changes in manufacturing processes have placed greater emphasis on assuring fuel quality and many processes can no longer tolerate near-substitutes such as distillate fuel oil and LPG. One way to take advantage of lower cost interruptible gas service contracts is to provide stand-by sources of gas onsite which can be used when the primary supply is curtailed. This paper describes the methods which an industrial gas consumer could use to store gas onsite (or close by an industrial factory) and their technical and economic advantages or limitations. The regulatory factors such as environmental and safety issues are reviewed and the advantages and disadvantages of each method are described. The application of emerging technologies such as storing natural gas on adsorbents at low pressure and solid absorption in LPG are reviewed and the research needed to make them acceptable is discussed. The potential applications in the marketplace are also discussed and the economics of onsite storage of natural gas is compared to other alternatives. (author). 11 refs, 5 figs, 1 tab

Trends in risks associated with gas

International Nuclear Information System (INIS)

Pequignot, H.; Bertin, M.

1980-01-01

'Gas' is regarded at present as one of the forms of energy which presents the least health problems. All studies comparing the hazards of the various forms of energy have come to the same conclusion. For reasons of method this article views the situation from the viewpoint of the responsibilities and liabilities of the gas undertakings. When the gas supplied to customers was produced from coal, the risks inherent in mining the coal were not added to those of the production and distribution of the gas. Likewise, the problems raised by the production and transport of petroleum products which may be used by the gas industry, apart from natural gas of course, will not be considered here. At the outset, three particular points deserve to be stressed: Hazards exist at the stage of use and not at that of production; in this respect, gas differs from nuclear power and coal and the problems of prevention are therefore quite different; The hazards have declined sharply in the course of the past 25 years, and even at the distribution stage they have become fewer than in the case of most other forms of energy; The collection of epidemiological data was, and still is, better than in other power industries

Light yield as a function of gas pressure and electric field in gas scintillation proportional counters

International Nuclear Information System (INIS)

Favata, F.; Smith, A.; Bavdaz, M.; Kowalski, T.Z.

1990-01-01

We have investigated the dependence of the scintillation light output for Xe on gas pressure in the range 0.14-1.4 bar, using a gas scintillation proportional counter, in different experimental configurations. We have compared our work with that of previous workers, and have shown that both our results and the results of previous authors are compatible with the intrinsic light output being independent of gas pressure, with any observed dependence being a pure experimental effect due to the spectral response of the various UV detectors used. We also use our experimental data for determining the ratio between the cross section of the Xe 2 ** +Xe→Xe 2 * +Xe reaction and the rate of the Xe 2 ** →2Xe+γ UV reaction. (orig.)

The response of the Tore Supra edge plasma to supersonic pulsed gas injection

Czech Academy of Sciences Publication Activity Database

Pánek, Radomír; Gunn, J. P.; Bucalossi, J.; Ďuran, Ivan; Geraud, A.; Hron, Martin; Loarer, T.; Pégourié, B.; Stöckel, Jan; Tsitrone, E.

337-339, č. 16 (2005), s. 530-534 ISSN 0022-3115. [Plasma Surface Interactions /16./. Portland, 24.5.2005-28.5.2005] R&D Projects: GA ČR(CZ) GP202/03/P062 Institutional research plan: CEZ:AV0Z20430508 Keywords : Edge plasma * Gas injection and fuelling * probes * Plasma flow * Tore Supra Subject RIV: BL - Plasma and Gas Discharge Physics Impact factor: 1.414, year: 2005

The effectiveness of policies to transform a gas-exporting country into a gas-transit country: The case of The Netherlands

International Nuclear Information System (INIS)

Schipperus, Ouren T.; Mulder, Machiel

2015-01-01

The Netherlands has been a major European natural gas producer and exporter for many decades, but now faces the challenge to deal with diminishing resources. In response, the Dutch government initiated a gas-hub strategy, which is the policy to transform the gas industry from an export-oriented business into a transit-oriented business. This policy included a number of investments in the gas infrastructure as well as institutional reforms to enhance the liquidity of the gas market. We study the effects of this gas-hub policy. Using hourly data on the Dutch gas balance over the period 2006–2013, we find that gas storage and trading have become more important, but that the level of gas in transit in the Netherlands remained fairly constant. Consequently, the Dutch gas industry is still mainly oriented on domestic production and export of gas, while the Dutch gas hub (TTF) has become a key virtual trading place. The policy lesson from the Dutch experience is that implementing a gas-hub strategy requires significant investments in the gas infrastructure, while their effects do not necessarily become visible in the short run. -- Highlights: •The Netherlands has been a major gas producer and exporter for decades. •This country implemented a gas hub policy to deal with diminishing resources. •We study the effects of this policy using hourly data over the period 2006–2013. •Storage and trading became more important, but transit hardly grew. •The investments in the gas hub did not have clear effects in the short term

Metal oxide nanostructures as gas sensing devices

CERN Document Server

Eranna, G

2016-01-01

Metal Oxide Nanostructures as Gas Sensing Devices explores the development of an integrated micro gas sensor that is based on advanced metal oxide nanostructures and is compatible with modern semiconductor fabrication technology. This sensor can then be used to create a compact, low-power, handheld device for analyzing air ambience. The book first covers current gas sensing tools and discusses the necessity for miniaturized sensors. It then focuses on the materials, devices, and techniques used for gas sensing applications, such as resistance and capacitance variations. The author addresses the issues of sensitivity, concentration, and temperature dependency as well as the response and recovery times crucial for sensors. He also presents techniques for synthesizing different metal oxides, particularly those with nanodimensional structures. The text goes on to highlight the gas sensing properties of many nanostructured metal oxides, from aluminum and cerium to iron and titanium to zinc and zirconium. The final...

Nonlinear-Based MEMS Sensors and Active Switches for Gas Detection

KAUST Repository

Bouchaala, Adam M.; Jaber, Nizar; Yassine, Omar; Shekhah, Osama; Chernikova, Valeriya; Eddaoudi, Mohamed; Younis, Mohammad I.

2016-01-01

The objective of this paper is to demonstrate the integration of a MOF thin film on electrostatically actuated microstructures to realize a switch triggered by gas and a sensing algorithm based on amplitude tracking. The devices are based on the nonlinear response of micromachined clamped-clamped beams. The microbeams are coated with a metal-organic framework (MOF), namely HKUST-1, to achieve high sensitivity. The softening and hardening nonlinear behaviors of the microbeams are exploited to demonstrate the ideas. For gas sensing, an amplitude-based tracking algorithm is developed to quantify the captured quantity of gas. Then, a MEMS switch triggered by gas using the nonlinear response of the microbeam is demonstrated. Noise analysis is conducted, which shows that the switch has high stability against thermal noise. The proposed switch is promising for delivering binary sensing information, and also can be used directly to activate useful functionalities, such as alarming.

Nonlinear-Based MEMS Sensors and Active Switches for Gas Detection

KAUST Repository

Bouchaala, Adam M.

2016-05-25

The objective of this paper is to demonstrate the integration of a MOF thin film on electrostatically actuated microstructures to realize a switch triggered by gas and a sensing algorithm based on amplitude tracking. The devices are based on the nonlinear response of micromachined clamped-clamped beams. The microbeams are coated with a metal-organic framework (MOF), namely HKUST-1, to achieve high sensitivity. The softening and hardening nonlinear behaviors of the microbeams are exploited to demonstrate the ideas. For gas sensing, an amplitude-based tracking algorithm is developed to quantify the captured quantity of gas. Then, a MEMS switch triggered by gas using the nonlinear response of the microbeam is demonstrated. Noise analysis is conducted, which shows that the switch has high stability against thermal noise. The proposed switch is promising for delivering binary sensing information, and also can be used directly to activate useful functionalities, such as alarming.

Nonlinear-Based MEMS Sensors and Active Switches for Gas Detection.

Science.gov (United States)

Bouchaala, Adam; Jaber, Nizar; Yassine, Omar; Shekhah, Osama; Chernikova, Valeriya; Eddaoudi, Mohamed; Younis, Mohammad I

2016-05-25

The objective of this paper is to demonstrate the integration of a MOF thin film on electrostatically actuated microstructures to realize a switch triggered by gas and a sensing algorithm based on amplitude tracking. The devices are based on the nonlinear response of micromachined clamped-clamped beams. The microbeams are coated with a metal-organic framework (MOF), namely HKUST-1, to achieve high sensitivity. The softening and hardening nonlinear behaviors of the microbeams are exploited to demonstrate the ideas. For gas sensing, an amplitude-based tracking algorithm is developed to quantify the captured quantity of gas. Then, a MEMS switch triggered by gas using the nonlinear response of the microbeam is demonstrated. Noise analysis is conducted, which shows that the switch has high stability against thermal noise. The proposed switch is promising for delivering binary sensing information, and also can be used directly to activate useful functionalities, such as alarming.

Separated influence of crude oil prices on regional natural gas import prices

International Nuclear Information System (INIS)

Ji, Qiang; Geng, Jiang-Bo; Fan, Ying

2014-01-01

This paper analyses the impact of global economic activity and international crude oil prices on natural gas import prices in three major natural gas markets using the panel cointegration model. It also investigates the shock impacts of the volatility and the increase and decrease of oil prices on regional natural gas import prices. The results show that both global economic activity and international crude oil prices have significant long-term positive effects on regional natural gas import prices. The volatility of international crude oil prices has a negative impact on regional natural gas import prices. The shock impact is weak in North America, lags in Europe and is most significant in Asia, which is mainly determined by different regional policies for price formation. In addition, the response of natural gas import prices to increases and decreases in international crude oil prices shows an asymmetrical mechanism, of which the decrease impact is relatively stronger. - Highlights: • Impacts of world economy and oil prices on regional natural gas prices are analysed • North American natural gas prices are mainly affected by world economy • Asian and European natural gas prices are mainly affected by oil prices • The volatility of oil prices has a negative impact on regional natural gas prices • The response of natural gas import prices to oil prices up and down shows asymmetry

Current status of natural gas in Asia and future problems; Asia no tennen gas josei no genjo to kongo no tenbo

Energy Technology Data Exchange (ETDEWEB)

Takahashi, K. [The Institute of Energy Economics, Tokyo (Japan)

1997-01-30

This paper describes current status of natural gas in individual countries of Asia and future prospects. Japan is the largest consuming country, and consumes 29% of Asia-Pacific region. Japan, Korea and Taiwan consume 35%. All of natural gas are imported. Indonesia, the largest LNG exporting country in the world, makes efforts to develop natural gas in response to the future shortage of oil with the economic growth. In Malaysia, natural gas utilization is extending for the diversification of energy. Natural gas utilization occupies 36% of primary energy consumption, which results in the reduced oil consumption. Brunei is an important natural gas supplier in Asia, and 90% of the production is exported. Australia has a large reserve of natural gas, which is exported besides domestic use. China has a large latent demand as well as India. In Taiwan, most of natural gas is imported. In Korea, demand of city gas has extended in addition to power generation, and it will extend in future. Current conditions in Vietnam and Thailand are also described. In the Philippine, natural gas is not used. 3 figs., 8 tabs.

A Model of Solid State Gas Sensors

Science.gov (United States)

Woestman, J. T.; Brailsford, A. D.; Shane, M.; Logothetis, E. M.

1997-03-01

Solid state gas sensors are widely used to measure the concentrations of gases such as CO, CH_4, C_3H_6, H_2, C_3H8 and O2 The applications of these sensors range from air-to-fuel ratio control in combustion processes including those in automotive engines and industrial furnaces to leakage detection of inflammable and toxic gases in domestic and industrial environments. As the need increases to accurately measure smaller and smaller concentrations, problems such as poor selectivity, stability and response time limit the use of these sensors. In an effort to overcome some of these limitations, a theoretical model of the transient behavior of solid state gas sensors has been developed. In this presentation, a model for the transient response of an electrochemical gas sensor to gas mixtures containing O2 and one reducing species, such as CO, is discussed. This model accounts for the transport of the reactive species to the sampling electrode, the catalyzed oxidation/reduction reaction of these species and the generation of the resulting electrical signal. The model will be shown to reproduce the results of published steady state models and to agree with experimental steady state and transient data.

Development of a detection sensor for lethal H2S gas.

Science.gov (United States)

Park, Young-Ho; Kim, Yong-Jae; Lee, Chang-Seop

2012-07-01

The gas which may be lethal to human body with short-term exposure in common industrial fields or workplaces in LAB may paralyze the olfactory sense and impose severe damages to central nervous system and lung. This study is concerned with the gas sensor which allows individuals to avoid the toxic gas that may be generated in the space with residues of organic wastes under 50 degrees C or above. This study investigates response and selectivity of the sensor to hydrogen sulfide gas with operating temperatures and catalysts. The thick-film semiconductor sensor for hydrogen sulfide gas detection was fabricated WO3/SnO2 prepared by sol-gel and precipitation methods. The nanosized SnO2 powder mixed with the various metal oxides (WO3, TiO2, and ZnO) and doped with transition metals (Au, Ru, Pd Ag and In). Particle sizes, specific surface areas and phases of sensor materials were investigated by SEM, BET and XRD analyses. The metal-WO3/SnO2 thick films were prepared by screen-printing method. The measured response to hydrogen sulfide gas is defined as the ratio (Ra/R,) of the resistance of WO3ISnO2 film in air to the resistance of WO3/SnO2 film in a hydrogen sulfide gas. It was shown that the highest response and selectivity of the sensor for hydrogen sulfide by doping with 1 wt% Ru and 10 wt% WO3 to SnO2 at the optimum operating temperature of 200 degrees C.

Thermal response of core and central-cavity components of a high-temperature gas-cooled reactor in the absence of forced convection coolant flow

International Nuclear Information System (INIS)

Whaley, R.L.; Sanders, J.P.

1976-09-01

A means of determining the thermal responses of the core and the components of a high-temperature gas-cooled reactor after loss of forced coolant flow is discussed. A computer program, using a finite-difference technique, is presented together with a solution of the confined natural convection. The results obtained are reasonable and demonstrate that the computer program adequately represents the confined natural convection

Fission-gas-bubble mobility in oxide fuel: a critical analysis

International Nuclear Information System (INIS)

Tam, S.W.; Johnson, C.E.

1983-08-01

The available volatile fission product release data has confirmed the general viability of the scaling model of volatile fission product release in which the fractional release rates of the volatile fission products scale as that of the fission gas. The question of whether fission gas bubbles can move sufficiently fast to be a significant mechanism responsible for fission gas release from the fuel is considered. The mean jump distance per jump of the hopping process in gas bubble motion is analyzed. Surface roughness is also considered

Effect of Ni Doping on Gas Sensing Performance of ZnO Thick Film Resistor

Directory of Open Access Journals (Sweden)

M. K. DEORE

2010-11-01

Full Text Available This work investigates the use of ZnO-NiO as a H2S metal oxide thick film gas sensor. To find the optimum ratio of NiO to ZnO, two compositions were prepared using different molecular percentages and prepared as a thick film paste. These pastes were then screen-printed onto glass substrates with suitable binder. The final composition of each film was determined using SEM analysis. The films were used to detect CO, CL2, ethanol, Amonia and H2S. For each composition tested, the highest responses where displayed for H2S gas. The Thick film having composition of equal molar ZnO and NiO shows the highest response at operating temp. 350 0C for 100 ppm level. The gas response, selectivity, response and recovery time of the sensor were measured and presented. The role played by NiO species is to improve the gas sensing performance is discussed.

Pre-monarchical political leadership among the Gas, with special ...

African Journals Online (AJOL)

... Gas to the coast. The transition from priestly theocracy to chiefly rule became necessary as a response to the pressure on the Gas as the middlemen between the merchants on the coast and the other inland groups. Institute of African Studies: Research Review Volume Research Review Supplement 17 2006: pp. 137-147 ...

Northern Hemisphere Winter Climate Response to Greenhouse Gas, Ozone, Solar and Volcanic Forcing

Science.gov (United States)

Shindell, Drew T.; Schmidt, Gavin A.; Miller, Ron L.; Rind, David; Hansen, James E. (Technical Monitor)

2001-01-01

The Goddard Institute for Space Studies (GISS) climate/middle atmosphere model has been used to study the impacts of increasing greenhouse gases, polar ozone depletion, volcanic eruptions, and solar cycle variability. We focus on the projection of the induced responses onto Northern Hemisphere winter surface climate. Changes in the model's surface climate take place largely through enhancement of existing variability patterns, with greenhouse gases, polar ozone depletion and volcanic eruptions primarily affecting the Arctic Oscillation (AO) pattern. Perturbations descend from the stratosphere to the surface in the model by altering the propagation of planetary waves coming up from the surface, in accord with observational evidence. Models lacking realistic stratospheric dynamics fail to capture these wave flux changes. The results support the conclusion that the stratosphere plays a crucial role in recent AO trends. We show that in our climate model, while ozone depletion has a significant effect, greenhouse gas forcing is the only one capable of causing the large, sustained increase in the AO observed over recent decades. This suggests that the AO trend, and a concurrent strengthening of the stratospheric vortex over the Arctic, are very likely anthropogenic in origin.

Gas and Gas Pains

Science.gov (United States)

... to produce gas. Often, relatively simple changes in eating habits can lessen bothersome gas. Certain digestive system disorders, ... such as soda and beer, increase stomach gas. Eating habits, such as eating too quickly, drinking through a ...

Sensitivity analysis and economic optimization studies of inverted five-spot gas cycling in gas condensate reservoir

Science.gov (United States)

Shams, Bilal; Yao, Jun; Zhang, Kai; Zhang, Lei

2017-08-01

Gas condensate reservoirs usually exhibit complex flow behaviors because of propagation response of pressure drop from the wellbore into the reservoir. When reservoir pressure drops below the dew point in two phase flow of gas and condensate, the accumulation of large condensate amount occurs in the gas condensate reservoirs. Usually, the saturation of condensate accumulation in volumetric gas condensate reservoirs is lower than the critical condensate saturation that causes trapping of large amount of condensate in reservoir pores. Trapped condensate often is lost due to condensate accumulation-condensate blockage courtesy of high molecular weight, heavy condensate residue. Recovering lost condensate most economically and optimally has always been a challenging goal. Thus, gas cycling is applied to alleviate such a drastic loss in resources. In gas injection, the flooding pattern, injection timing and injection duration are key parameters to study an efficient EOR scenario in order to recover lost condensate. This work contains sensitivity analysis on different parameters to generate an accurate investigation about the effects on performance of different injection scenarios in homogeneous gas condensate system. In this paper, starting time of gas cycling and injection period are the parameters used to influence condensate recovery of a five-spot well pattern which has an injection pressure constraint of 3000 psi and production wells are constraint at 500 psi min. BHP. Starting injection times of 1 month, 4 months and 9 months after natural depletion areapplied in the first study. The second study is conducted by varying injection duration. Three durations are selected: 100 days, 400 days and 900 days. In miscible gas injection, miscibility and vaporization of condensate by injected gas is more efficient mechanism for condensate recovery. From this study, it is proven that the application of gas cycling on five-spot well pattern greatly enhances condensate recovery

Gas, gas, gas... discoveries and developments booming worldwide

International Nuclear Information System (INIS)

Maxwell, F.

2000-01-01

Deep water exploration is yielding more than billion barrel oil fields. Unocal's 3 May discovery of 2-3 Tcf of gas in its Kutei block of Indonesia marks the first major discovery of natural gas in the deep water frontier: Wildcats Gula and Gada were drilled in over 1800 m of water as part of an aggressive search for gas instigated by Unocal last year. The author makes a survey of gas exploration and development throughout the world. (author)

Titanium dioxide-based carbon monoxide gas sensors: Effects of crystallinity and chemistry on sensitivity

Science.gov (United States)

Seeley, Zachary Mark

Among metal-oxide gas sensors which change electrical resistive properties upon exposure to target gasses, titanium dioxide (TiO2) has received attention for its sensitivity and stability during high temperature (>500°C) operation. However, due to the sensing mechanism sensitivity, selectivity, and stability remain as critical deficiencies to be resolved before these sensors reach commercial use. In this study, TiO2 thick films of approximately 30mum and thin films of approximately 1mum thick were fabricated to assess the influence of their material properties on gas sensing mechanism. Increased calcination temperature of TiO2 thick films led to grain growth, reduction in specific surface area, and particle-particle necking. These properties are known to degrade sensitivity; however the measured carbon monoxide (CO) gas response improved with increasing calcination temperature up to 800°C. It was concluded that the sensing improvement was due to increased crystallinity within the films. Sensing properties of TiO2 thin films of were also dependent on crystallization, however; due to the smaller volume of material, they reached optimized crystallization at lower temperatures of 650°C, compared to 800°C for thick films. Incorporation of tungsten (W) and nickel (Ni) ions into the films created donor and acceptor defect sites, respectively, within the electronic band gap of TiO2. The additional n-type defects in W-doped TiO 2 improved n-type CO response, while p-type defects in Ni-doped TiO 2 converted the gas response to p-type. Chemistry of thin films had a more significant impact on the electrical properties and gas response than did microstructure or crystallinity. Doped films could be calcined at higher temperatures and yet remain highly sensitive to CO. Thin films with p-n bi-layer structure were fabricated to determine the influence of a p-n junction on gas sensing properties. No effect of the junction was observed and the sensing response neared the average

Curvature Induced by Amyloplast Magnetophoresis in Protonemata of the Moss Ceratodon purpureus1

Science.gov (United States)

Kuznetsov, Oleg A.; Schwuchow, Jochen; Sack, Fred D.; Hasenstein, Karl H.

1999-01-01

After gravistimulation of Ceratodon purpureus (Hedw.) Brid. protonemata in the dark, amyloplast sedimentation was followed by upward curvature in the wild-type (WT) and downward curvature in the wwr mutant (wrong way response). We used ponderomotive forces induced by high-gradient magnetic fields (HGMF) to simulate the effect of gravity and displace the presumptive statoliths. The field was applied by placing protonemata either between two permanent magnets at the edge of the gap, close to the edge of a magnetized ferromagnetic wedge, or close to a small (<1 mm) permanent magnet. Continuous application of an HGMF in all three configurations resulted in plastid displacement and induced curvature in tip cells of WT and wwr protonemata. WT cells curved toward the HGMF, and wwr cells curved away from the HGMF, comparable to gravitropism. Plastids isolated from protonemal cultures had densities ranging from 1.24 to 1.38 g cm−3. Plastid density was similar for both genotypes, but the mutant contained larger plastids than the WT. The size difference might explain the stronger response of the wwr protonemata to the HGMF. Our data support the plastid-based theory of gravitropic sensing and suggest that HGMF-induced ponderomotive forces can substitute for gravity. PMID:9952461

Requirements for gas quality and gas appliances

NARCIS (Netherlands)

Levinsky, Howard; Gersen, Sander; Kiewiet, Bert

2015-01-01

Introduction The gas transmission network in the Netherlands transports two different qualities of gas, low-calorific gas known as G-gas or L-gas and, high calorific gas (H-gas). These two gas qualities are transported in separate networks, and are connected by means of five blending and conversion

Zirconia-based solid state chemical gas sensors

CERN Document Server

Zhuiykov, S

2000-01-01

This paper presents an overview of chemical gas sensors, based on solid state technology, that are sensitive to environmental gases, such as O sub 2 , SO sub x , NO sub x , CO sub 2 and hydrocarbons. The paper is focussed on performance of electrochemical gas sensors that are based on zirconia as a solid electrolyte. The paper considers sensor structures and selection of electrode materials. Impact of interfaces on sensor performance is discussed. This paper also provides a brief overview of electrochemical properties of zirconia and their effect on sensor performance. Impact of auxiliary materials on sensors performance characteristics, such as sensitivity, selectivity, response time and recovery time, is also discussed. Dual gas sensors that can be applied for simultaneous monitoring of the concentration of both oxygen and other gas phase components, are briefly considered

77 FR 23105 - Supporting Safe and Responsible Development of Unconventional Domestic Natural Gas Resources

Science.gov (United States)

2012-04-17

... 2011, natural gas provided 25 percent of the energy consumed in the United States. Its production creates jobs and provides economic benefits to the entire domestic production supply chain, as well as to... appropriate safeguards, natural gas can provide a cleaner source of energy than other fossil fuels. For these...

PSO-RBF Neural Network PID Control Algorithm of Electric Gas Pressure Regulator

Directory of Open Access Journals (Sweden)

Yuanchang Zhong

2014-01-01

Full Text Available The current electric gas pressure regulator often adopts the conventional PID control algorithm to take drive control of the core part (micromotor of electric gas pressure regulator. In order to further improve tracking performance and to shorten response time, this paper presents an improved PID intelligent control algorithm which applies to the electric gas pressure regulator. The algorithm uses the improved RBF neural network based on PSO algorithm to make online adjustment on PID parameters. Theoretical analysis and simulation result show that the algorithm shortens the step response time and improves tracking performance.

Effects of ethylene on the kinetics of curvature and auxin redistribution in gravistimulated roots of Zea mays

Science.gov (United States)

Lee, J. S.; Evans, M. L.

1990-01-01

We tested the involvement of ethylene in maize (Zea mays L.) root gravitropism by measuring the kinetics of curvature and lateral auxin movement in roots treated with ethylene, inhibitors of ethylene synthesis, or inhibitors of ethylene action. In the presence of ethylene the latent period of gravitropic curvature appeared to be increased somewhat. However, ethylene-treated roots continued to curve after control roots had reached their final angle of curvature. Consequently, maximum curvature in the presence of ethylene was much greater in ethylene-treated roots than in controls. Inhibitors of ethylene biosynthesis or action had effects on the kinetics of curvature opposite to that of ethylene, i.e. the latent period appeared to be shortened somewhat while total curvature was reduced relative to that of controls. Label from applied 3H-indole-3-acetic acid was preferentially transported toward the lower side of stimulated roots. In parallel with effects on curvature, ethylene treatment delayed the development of gravity-induced asymmetric auxin movement across the root but extended its duration once initiated. The auxin transport inhibitor, 1-N-naphthylphthalamic acid reduced both gravitropic curvature and the effect of ethylene on curvature. Since neither ethylene nor inhibitors of ethylene biosynthesis or action prevented curvature, we conclude that ethylene does not mediate the primary differential growth response causing curvature. Because ethylene affects curvature and auxin transport in parallel, we suggest that ethylene modifies curvature by affecting gravity-induced lateral transport of auxin, perhaps by interfering with adaptation of the auxin transport system to the gravistimulus.

Breathing Clean : Considering the Switch to Natural Gas Buses

OpenAIRE

Kojima, Masami

2001-01-01

In response to emerging epidemiological evidence of the toxicity of diesel vehicular emissions, there is growing interest in substituting conventional diesel with much cleaner natural gas in cities where ambient concentrations of particulate matter are markedly higher than what is internationally considered acceptable. This paper compares the performance of natural gas and conventional die...

Gas sensing with gold-decorated vertically aligned carbon nanotubes.

Science.gov (United States)

Mudimela, Prasantha R; Scardamaglia, Mattia; González-León, Oriol; Reckinger, Nicolas; Snyders, Rony; Llobet, Eduard; Bittencourt, Carla; Colomer, Jean-François

2014-01-01

Vertically aligned carbon nanotubes of different lengths (150, 300, 500 µm) synthesized by thermal chemical vapor deposition and decorated with gold nanoparticles were investigated as gas sensitive materials for detecting nitrogen dioxide (NO2) at room temperature. Gold nanoparticles of about 6 nm in diameter were sputtered on the top surface of the carbon nanotube forests to enhance the sensitivity to the pollutant gas. We showed that the sensing response to nitrogen dioxide depends on the nanotube length. The optimum was found to be 300 µm for getting the higher response. When the background humidity level was changed from dry to 50% relative humidity, an increase in the response to NO2 was observed for all the sensors, regardless of the nanotube length.

Gas sensing with gold-decorated vertically aligned carbon nanotubes

Directory of Open Access Journals (Sweden)

Prasantha R. Mudimela

2014-06-01

Full Text Available Vertically aligned carbon nanotubes of different lengths (150, 300, 500 µm synthesized by thermal chemical vapor deposition and decorated with gold nanoparticles were investigated as gas sensitive materials for detecting nitrogen dioxide (NO2 at room temperature. Gold nanoparticles of about 6 nm in diameter were sputtered on the top surface of the carbon nanotube forests to enhance the sensitivity to the pollutant gas. We showed that the sensing response to nitrogen dioxide depends on the nanotube length. The optimum was found to be 300 µm for getting the higher response. When the background humidity level was changed from dry to 50% relative humidity, an increase in the response to NO2 was observed for all the sensors, regardless of the nanotube length.

Electrospray-printed nanostructured graphene oxide gas sensors

Science.gov (United States)

Taylor, Anthony P.; Velásquez-García, Luis F.

2015-12-01

We report low-cost conductometric gas sensors that use an ultrathin film made of graphene oxide (GO) nanoflakes as transducing element. The devices were fabricated by lift-off metallization and near-room temperature, atmospheric pressure electrospray printing using a shadow mask. The sensors are sensitive to reactive gases at room temperature without requiring any post heat treatment, harsh chemical reduction, or doping with metal nanoparticles. The sensors’ response to humidity at atmospheric pressure tracks that of a commercial sensor, and is linear with changes in humidity in the 10%-60% relative humidity range while consuming recipes yielded nearly identical response characteristics, suggesting that intrinsic properties of the film control the sensing mechanism. The gas sensors successfully detected ammonia at concentrations down to 500 ppm (absolute partial pressure of ˜5 × 10-4 T) at ˜1 T pressure, room temperature conditions. The sensor technology can be used in a great variety of applications including air conditioning and sensing of reactive gas species in vacuum lines and abatement systems.

Process and system for removing impurities from a gas

Science.gov (United States)

Henningsen, Gunnar; Knowlton, Teddy Merrill; Findlay, John George; Schlather, Jerry Neal; Turk, Brian S

2014-04-15

A fluidized reactor system for removing impurities from a gas and an associated process are provided. The system includes a fluidized absorber for contacting a feed gas with a sorbent stream to reduce the impurity content of the feed gas; a fluidized solids regenerator for contacting an impurity loaded sorbent stream with a regeneration gas to reduce the impurity content of the sorbent stream; a first non-mechanical gas seal forming solids transfer device adapted to receive an impurity loaded sorbent stream from the absorber and transport the impurity loaded sorbent stream to the regenerator at a controllable flow rate in response to an aeration gas; and a second non-mechanical gas seal forming solids transfer device adapted to receive a sorbent stream of reduced impurity content from the regenerator and transfer the sorbent stream of reduced impurity content to the absorber without changing the flow rate of the sorbent stream.

Large scale gas injection test (Lasgit): Results from two gas injection tests

International Nuclear Information System (INIS)

Cuss, R. J.; Harrington, J. F.; Noy, D. J.; Wikman, A.; Sellin, P.

2011-01-01

entry occurs at a gas pressure close to, or slightly in excess of, the local stress state and is associated with a rapid increase in flux, linked to a series of kicks in axial and radial stress and pore water pressure. Post peak gas flux exhibits dynamic behaviour, symptomatic of unstable gas flow. When gas injection is stopped, flux into the clay rapidly reduces before entering an extended period of very small flows. This is accompanied by a rapid reduction in pressure which decays to an asymptotic value close to that of the total stress locally within the deposition hole. Examination of the data shows considerable evidence for the development of a highly-dynamic, tortuous network of pressure induced pathways which evolve both temporally and geo-spatially within the clay, opening and closing due to local changes in gas pressure and/or effective stress. These detailed observations do not conform to standard concepts of two-phase flow. The bentonite response to the passage of gas suggests that pathway dilation is the primary mechanism governing gas migration within the Lasgit system. The important coupling between gas, stress and pore water pressure at the repository scale is clearly evident with the data. The importance and interdependencies of this coupling will be investigated in future experiments planned at the Lasgit experimental site. (authors)

Gas expulsion in highly substructured embedded star clusters

Science.gov (United States)

Farias, J. P.; Fellhauer, M.; Smith, R.; Domínguez, R.; Dabringhausen, J.

2018-06-01

We investigate the response of initially substructured, young, embedded star clusters to instantaneous gas expulsion of their natal gas. We introduce primordial substructure to the stars and the gas by simplistically modelling the star formation process so as to obtain a variety of substructure distributed within our modelled star-forming regions. We show that, by measuring the virial ratio of the stars alone (disregarding the gas completely), we can estimate how much mass a star cluster will retain after gas expulsion to within 10 per cent accuracy, no matter how complex the background structure of the gas is, and we present a simple analytical recipe describing this behaviour. We show that the evolution of the star cluster while still embedded in the natal gas, and the behaviour of the gas before being expelled, is crucial process that affect the time-scale on which the cluster can evolve into a virialized spherical system. Embedded star clusters that have high levels of substructure are subvirial for longer times, enabling them to survive gas expulsion better than a virialized and spherical system. By using a more realistic treatment for the background gas than our previous studies, we find it very difficult to destroy the young clusters with instantaneous gas expulsion. We conclude that gas removal may not be the main culprit for the dissolution of young star clusters.

Nonlinear-Based MEMS Sensors and Active Switches for Gas Detection

Directory of Open Access Journals (Sweden)

Adam Bouchaala

2016-05-01

Full Text Available The objective of this paper is to demonstrate the integration of a MOF thin film on electrostatically actuated microstructures to realize a switch triggered by gas and a sensing algorithm based on amplitude tracking. The devices are based on the nonlinear response of micromachined clamped-clamped beams. The microbeams are coated with a metal-organic framework (MOF, namely HKUST-1, to achieve high sensitivity. The softening and hardening nonlinear behaviors of the microbeams are exploited to demonstrate the ideas. For gas sensing, an amplitude-based tracking algorithm is developed to quantify the captured quantity of gas. Then, a MEMS switch triggered by gas using the nonlinear response of the microbeam is demonstrated. Noise analysis is conducted, which shows that the switch has high stability against thermal noise. The proposed switch is promising for delivering binary sensing information, and also can be used directly to activate useful functionalities, such as alarming.

Nonlinear-Based MEMS Sensors and Active Switches for Gas Detection

Science.gov (United States)

Bouchaala, Adam; Jaber, Nizar; Yassine, Omar; Shekhah, Osama; Chernikova, Valeriya; Eddaoudi, Mohamed; Younis, Mohammad I.

2016-01-01

The objective of this paper is to demonstrate the integration of a MOF thin film on electrostatically actuated microstructures to realize a switch triggered by gas and a sensing algorithm based on amplitude tracking. The devices are based on the nonlinear response of micromachined clamped-clamped beams. The microbeams are coated with a metal-organic framework (MOF), namely HKUST-1, to achieve high sensitivity. The softening and hardening nonlinear behaviors of the microbeams are exploited to demonstrate the ideas. For gas sensing, an amplitude-based tracking algorithm is developed to quantify the captured quantity of gas. Then, a MEMS switch triggered by gas using the nonlinear response of the microbeam is demonstrated. Noise analysis is conducted, which shows that the switch has high stability against thermal noise. The proposed switch is promising for delivering binary sensing information, and also can be used directly to activate useful functionalities, such as alarming. PMID:27231914

Kinetic response study in chemiresistive gas sensor based on carbon nanotube surface functionalized with substituted phthalocyanines

Science.gov (United States)

Sharma, Anshul Kumar; Kumar, Pankaj; Saini, Rajan; Bedi, R. K.; Mahajan, Aman

2016-05-01

A kind of hybrid material is prepared by functionalizing multi-wall carbon nanotubes (MWCNTs-COOH) with substituted copper phthalocyanine and the formation of CuPcOC8/MWCNTs-COOH hybrid is confirmed by scanning electron microscopy and transmission electron microscopy. The results indicated that on the surface of nanotubes substituted CuPcOC8 derivatives has been successfully anchored through π-π stacking interaction. The gas sensing application of the fabricated hybrid material is tested upon exposure to different hazardous species, specifically NO2, NO, Cl2 and NH3 at operating temperature of 150˚C. It has been demonstrated that for Cl2 minimum detection limit of CuPcOC8/MWCNTs-COOH hybrid is 100 ppb. The response of hybrid sensor is found to be increased with increase in the concentration of Cl2.

Selectivity enhancement of indium-doped SnO2 gas sensors

International Nuclear Information System (INIS)

Salehi, A.

2002-01-01

Indium doping was used to enhance the selectivity of SnO 2 gas sensor. Both indium-doped and undoped SnO 2 gas sensors fabricated with different deposition techniques were investigated. The changes in the sensitivity of the sensors caused by selective gases (hydrogen and wood smoke) ranging from 500 to 3000 ppm were measured at different temperatures from 50 to 300 deg. C. The sensitivity peaks of the samples exhibit different values for selective gases with a response time of approximately 0.5 s. Thermally evaporated indium-doped SnO 2 gas sensor shows a considerable increase in the sensitivity peak of 27% in response to wood smoke, whereas it shows a sensitivity peak of 7% to hydrogen. This is in contrast to the sputter deposited indium-doped SnO 2 gas sensor, which exhibits a much lower sensitivity peak of approximately 2% to hydrogen and wood smoke compared to undoped SnO 2 gas sensors fabricated by chemical vapor deposition and spray pyrolysis. Scanning electron microscopy shows that different deposition techniques result in different porosity of the films. It is observed that the thermally evaporated indium-doped SnO 2 gas sensor shows high porosity, while the sputtered sample exhibits almost no porosity

Temperature and distortion transients in gas tungsten-arc weldments

International Nuclear Information System (INIS)

Glickstein, S.S.; Friedman, E.

1979-10-01

An analysis and test program to develop a fundamental understanding of the gas tungsten-arc welding process has been undertaken at the Bettis Atomic Power Laboratory to develop techniques to determine and control the various welding parameters and weldment conditions so as to result in optimum weld response characteristics. These response characteristics include depth of penetration, weld bead configuration, weld bead sink and roll, distortion, and cracking sensitivity. The results are documented of that part of the program devoted to analytical and experimental investigations of temperatures, weld bead dimensions, and distortions for moving gas tungsten-arc welds applied to Alloy 600 plates

Inhibitors of plant hormone transport

Czech Academy of Sciences Publication Activity Database

Klíma, Petr; Laňková, Martina; Zažímalová, Eva

2016-01-01

Roč. 253, č. 6 (2016), s. 1391-1404 ISSN 0033-183X R&D Projects: GA MŠk(CZ) LD15088 Institutional support: RVO:61389030 Keywords : polar auxin transport * acid-binding protein * gnom arf-gef * equilibrative nucleoside transporter * efflux carrier polarity * plasma-membrane-protein * cultured tobacco cells * arabidopsis-thaliana * gravitropic response * brefeldin-a * Plant hormones * Transport * Inhibitors * Auxin * Cytokinins * Strigolactones * Abscisic acid * Cell biology Subject RIV: ED - Physiology Impact factor: 2.870, year: 2016

The cGAS-cGAMP-STING pathway connects DNA damage to inflammation, senescence, and cancer.

Science.gov (United States)

Li, Tuo; Chen, Zhijian J

2018-05-07

Detection of microbial DNA is an evolutionarily conserved mechanism that alerts the host immune system to mount a defense response to microbial infections. However, this detection mechanism also poses a challenge to the host as to how to distinguish foreign DNA from abundant self-DNA. Cyclic guanosine monophosphate (GMP)-adenosine monophosphate (AMP) synthase (cGAS) is a DNA sensor that triggers innate immune responses through production of the second messenger cyclic GMP-AMP (cGAMP), which binds and activates the adaptor protein STING. However, cGAS can be activated by double-stranded DNA irrespective of the sequence, including self-DNA. Although how cGAS is normally kept inactive in cells is still not well understood, recent research has provided strong evidence that genomic DNA damage leads to cGAS activation to stimulate inflammatory responses. This review summarizes recent findings on how genomic instability and DNA damage trigger cGAS activation and how cGAS serves as a link from DNA damage to inflammation, cellular senescence, and cancer. © 2018 Li and Chen.

Nanostructured ZnO films for potential use in LPG gas sensors

Science.gov (United States)

Latyshev, V. M.; Berestok, T. O.; Opanasyuk, A. S.; Kornyushchenko, A. S.; Perekrestov, V. I.

2017-05-01

The aim of the work was to obtain ZnO nanostructures with heightened surface area and to study relationship between formation method and gas sensor properties towards propane-butane mixture (LPG). In order to synthesize ZnO nanostructures chemical and physical formation methods have been utilized. The first one was chemical bath deposition technology and the second one magnetron sputtering of Zn followed by oxidation. Optimal method and technological parameters corresponding to formation of material with the highest sensor response have been determined experimentally. Dynamical gas sensor response at different temperature values and dependencies of the sensor sensitivity on the temperature at different LPG concentrations in air have been investigated. It has been found, that sensor response depends on the sample morphology and has the highest value for the structure consisting of thin nanowires. The factors that lead to the decrease in the gas sensor operating temperature have been determined.

Regulating power for gas boilers in houses. Surplus power from wind power plants for natural gas boilers; Regulerkraft pae villakedelomraedet. Overskuds-el fra vindmoeller til naturgaskedler

Energy Technology Data Exchange (ETDEWEB)

Larsen, Michael; Frederiksen, Karsten V.

2011-08-15

The aim of the project is to clarify the potential development of a simple electric heating unit to gas installations in houses, so that natural gas for heating can be replaced with surplus wind power. The gas network in this way becomes an energy storage for power. In this preliminary project the aim is to estimate the value of these solutions and to verify in the lab, whether it is possible to establish and activate a simple and inexpensive electric heating unit on a typical gas boiler installation. In addition, it must be clarified whether it is possible to establish a simple communication with price signal from the balancing responsible. Based on the preliminary analyses and based on the electric heating unit, which is used in this project, it is estimated that there is a potential for the use of an electric heating unit on gas boilers in houses, and there is also a market, although there are limitations in relation to space and possibly also to the price. The price is estimated to be between 1,500 and 3,000 DKK per. installation (installed). However, this should be further investigated, including that the power balancing responsible /electricity trading companies assess the social value of using the electric heating unit as an element in the regulating power market. Regarding price signal, it is clear that communication opportunities are present at least with two of the balancing responsible companies, but it requires adaptation before a simple price signal to a gas boiler installation can be established. Price wise it is considered feasible. (LN)

Study on the inside gas flow visualization of oxygen sensor cover; Kashika ni yoru O2 sensor cover nai no gas nagare hyoka

Energy Technology Data Exchange (ETDEWEB)

Hocho, S; Mitsuishi, Y; Inagaki, M [Nippon Soken, Inc., Tokyo (Japan); Hamaguchi, S; Mizusawa, K [Toyota Motor Corp., Aichi (Japan)

1997-10-01

In order to make clear the difference of the response time between the oxygen sensors with different protection covers, we visualized gas flow inside of sensor covers by means of two experimental methods: One is `Smoke Suspension Method` using liquid paraffin vapor as the smoke. With smoke suspension method, we detected the streamlines inside of the covers. The other is `Color Reaction Method` using the reaction of phenolphthalein and NH3 gas. With color reaction method, we confirmed the streamline inside of the cover and furthermore detected the difference of the response time of each sensor. 3 refs., 7 figs., 1 tab.

Investigations of X-ray response of single wire anode Ar-N2 flow type gas scintillation proportional counters

International Nuclear Information System (INIS)

Garg, S.P.; Sharma, R.C.

1984-01-01

The X-ray response of single wire anode gas scintillation proportional counters of two different geometries operated with argon+nitrogen gases in continuous flow has been investigated with wire anodes of diameters 25 μm to 1.7 mm. An energy resolution of 19% is obtained for 5.9 keV X-rays entering the counter perpendicular to the anode in pill-box geometry with 25 μm diameter anode. With cylindrical geometry counters energy obtained at 5.9 keV are 18%, 24% and 33% for 50 μm, 0.5 mm and 1.7 mm diameter anodes respectively. An analysis of the observed resolution shows that the contribution from photon counting statistics to the relative variance of scintillation pulses even for X-rays in Ar-N 2 single wire anode gas scintillation proportional counters is small and is not a limiting factor. The energy resolution with thicker anodes, where the contribution from the variance of the charge multiplication factor also has been minimised, is found to deteriorate mainly by the interaction in the scintillation production region. Comments are made on the possibility of improvement in energy resolution by suppression of pulses due to such interactions with the help of the pulse risetime discrimination technique. (orig.)

A comparative study of gas-gas miscibility processes in underground gas storage reservoirs

Energy Technology Data Exchange (ETDEWEB)

Rafiee, M.M.; Schmitz, S. [DBI - Gastechnologisches Institut gGmbH, Freiberg (Germany)

2013-08-01

Intermixture of gases in underground gas reservoirs have had great weight for natural gas storage in UGS projects with substitution of cushion gas by inert gases or changing the stored gas quality or origin, as for the replacement of town gas by natural gas. It was also investigated during the last years for Enhanced Gas Recovery (EGR) and Carbon Capture and Storage (CCS) projects. The actual importance of its mechanisms is discussed for the H{sub 2} storage in Power to Gas to Power projects (PGP). In these approaches miscibility of the injected gas with the gas in place in the reservoir plays an important role in the displacement process. The conditions and parameters for the gas-gas displacement and mixing have been investigated in previous projects, as e.g. the miscibility of CO{sub 2} with natural gas (CLEAN). Furthermore the miscibility process of town gas with natural gas and sauer gas with sweet gas were also previously measured and compared in laboratory. The objective of this work is to investigate the miscibility of H{sub 2} injection into natural gas reservoirs using a compositional and a black oil reservoir simulator. Three processes of convection, dispersion and diffusion are considered precisely. The effect of gas miscibility is studied for both simulators and the results are compared to find optimum miscibility parameters. The findings of this work could be helpful for further pilot and field case studies to predict and monitor the changes in gas composition and quality. In future this monitoring might become more important when PGP together with H{sub 2}-UGS, as storage technology, will help to successfully implement the change to an energy supply from more renewable sources. Similarly the method confirms the use of the black oil simulator as an alternative for gas-gas displacement and sequestration reservoir simulation in comparison to the compositional simulator. (orig.)

The structural basis of gas-responsive transcription by the human nuclear hormone receptor REV-ERBbeta.

Directory of Open Access Journals (Sweden)

Keith I Pardee

2009-02-01

Full Text Available Heme is a ligand for the human nuclear receptors (NR REV-ERBalpha and REV-ERBbeta, which are transcriptional repressors that play important roles in circadian rhythm, lipid and glucose metabolism, and diseases such as diabetes, atherosclerosis, inflammation, and cancer. Here we show that transcription repression mediated by heme-bound REV-ERBs is reversed by the addition of nitric oxide (NO, and that the heme and NO effects are mediated by the C-terminal ligand-binding domain (LBD. A 1.9 A crystal structure of the REV-ERBbeta LBD, in complex with the oxidized Fe(III form of heme, shows that heme binds in a prototypical NR ligand-binding pocket, where the heme iron is coordinately bound by histidine 568 and cysteine 384. Under reducing conditions, spectroscopic studies of the heme-REV-ERBbeta complex reveal that the Fe(II form of the LBD transitions between penta-coordinated and hexa-coordinated structural states, neither of which possess the Cys384 bond observed in the oxidized state. In addition, the Fe(II LBD is also able to bind either NO or CO, revealing a total of at least six structural states of the protein. The binding of known co-repressors is shown to be highly dependent upon these various liganded states. REV-ERBs are thus highly dynamic receptors that are responsive not only to heme, but also to redox and gas. Taken together, these findings suggest new mechanisms for the systemic coordination of molecular clocks and metabolism. They also raise the possibility for gas-based therapies for the many disorders associated with REV-ERB biological functions.

The Structural Basis of Gas-Responsive Transcription by the Human Nuclear Hormone Receptor REV-ERBβ

Science.gov (United States)

Pardee, Keith I; Xu, Xiaohui; Reinking, Jeff; Schuetz, Anja; Dong, Aiping; Liu, Suya; Zhang, Rongguang; Tiefenbach, Jens; Lajoie, Gilles; Plotnikov, Alexander N; Botchkarev, Alexey; Krause, Henry M; Edwards, Aled

2009-01-01

Heme is a ligand for the human nuclear receptors (NR) REV-ERBα and REV-ERBβ, which are transcriptional repressors that play important roles in circadian rhythm, lipid and glucose metabolism, and diseases such as diabetes, atherosclerosis, inflammation, and cancer. Here we show that transcription repression mediated by heme-bound REV-ERBs is reversed by the addition of nitric oxide (NO), and that the heme and NO effects are mediated by the C-terminal ligand-binding domain (LBD). A 1.9 Å crystal structure of the REV-ERBβ LBD, in complex with the oxidized Fe(III) form of heme, shows that heme binds in a prototypical NR ligand-binding pocket, where the heme iron is coordinately bound by histidine 568 and cysteine 384. Under reducing conditions, spectroscopic studies of the heme-REV-ERBβ complex reveal that the Fe(II) form of the LBD transitions between penta-coordinated and hexa-coordinated structural states, neither of which possess the Cys384 bond observed in the oxidized state. In addition, the Fe(II) LBD is also able to bind either NO or CO, revealing a total of at least six structural states of the protein. The binding of known co-repressors is shown to be highly dependent upon these various liganded states. REV-ERBs are thus highly dynamic receptors that are responsive not only to heme, but also to redox and gas. Taken together, these findings suggest new mechanisms for the systemic coordination of molecular clocks and metabolism. They also raise the possibility for gas-based therapies for the many disorders associated with REV-ERB biological functions. PMID:19243223

Gas: an asset for the climate?

International Nuclear Information System (INIS)

Icart, Laura; Boesinger, Cecile

2015-01-01

Within the perspective and context of the soon coming COP 21, a set of articles addresses the solutions developed by the gas industry to create a green energy with the so-called renewable gases. A manager explains the role enterprises may play and their responsibilities to face the climate challenge. An article outlines the still high level of subsidies awarded to fossil energies in the world (notably in OECD countries) which goes against efforts to reduce gas emissions and to struggle against climate change. The next article presents the gas booster technology and its associated techniques which is used to empty pressurized gas ducts to perform works without releasing natural gas in the atmosphere. A researcher then discusses the role gas may have in a new global strategy for climate. Then, while mentioning an experiment in Chagny, an article briefly comments the development of the bio-methane sector. A map is given with indication of the commitments of gas-producing and gas-consuming countries in terms of objectives of reduction of greenhouse gas emissions, of share of renewable energy. The next article presents the recently opened installation for the processing of biogas issued from sludge of a wastewater treatment plant near Strasbourg (reactions of different involved actors are given). Different persons from the gas sector (Engie, Butagaz, GRTgaz, TIGF, professional bodies) and in charge of innovation, sustainable development or environment give their point of view on expectations and projects of their company to face the climate challenge. An article then comments the success of recent tests performed on the integration of renewable isobutene into gas bottle for domestic use, and a last one reports examples which illustrate the expertise of Butagaz in the agriculture sector to help farmers to improve the energy capacity of their barns

Economic growth and greenhouse gas emissions

Energy Technology Data Exchange (ETDEWEB)

Ansuategi, Alberto [Environment Department, University of York, York (United Kingdom); Escapa, Marta [Foundations of Economic Analysis Department, University of the Basque Country, Bilbao (Spain)

2002-01-01

Recent empirical research has examined the relationship between certain indicators of environmental degradation and income, concluding that in some cases an inverted U-shaped relationship, which has been called an environmental Kuznets curve (EKC), exists between these variables. Unfortunately, this inverted U-shaped relationship does not hold for greenhouse gas emissions. One explanation of the absence of EKC-like behavior in greenhouse gas emissions is that greenhouse gases are special pollutants that create global, not local, disutility. But the international nature of global warming is not the only reason that prevents de-linking greenhouse gas emissions from economic growth. The intergenerational nature of the negative impact of greenhouse gas emissions may have also been an important factor preventing the implementation of greenhouse gas abatement measures in the past. In this paper we explore the effect that the presence of intergenerational spillovers has on the emissions-income relationship. We use a numerically calibrated overlapping generations model of climate-economy interactions. We conclude that: (1) the intertemporal responsibility of the regulatory agency, (2) the institutional capacity to make intergenerational transfers and (3) the presence of intergenerationally lagged impact of emissions constitute important determinants of the relationship between economic growth and greenhouse gas emissions.

British Gas plans global gas unit expansion

International Nuclear Information System (INIS)

Vielvoye, R.

1991-01-01

This paper reports on developing a global gas business, a British Gas plc's strategy for evolving a state owned U.K. gas company to a privatized worldwide oil and gas giant. By 2000, BG's global gas business is expected to provide 20% of its revenues, compared with 40% each from its exploration and production operations and its U.K. gas business. The global gas unit (GGU) plans to meet its targets mainly through acquiring holdings in gas transmission and distribution companies around the world. In the 12 months since GGU was established, it has made two such major acquisitions in this area. BG acquired Consumers Gas Co., Ltd., Ontario, Canada's biggest natural gas distribution company, for $943.5 million. It also took a 10% stake in Catalana de Gas SA, Barcelona, the largest privately owned gas utility in Spain and in terms of number of customers, the fourth largest in western Europe. BG also is targeting additional revenues from developing gas fired cogeneration systems in developing countries with gas reserves but no established transmission and distribution systems

Active mems microbeam device for gas detection

KAUST Repository

Bouchaala, Adam M.; Jaber, Nizar; Younis, Mohammad I.

2017-01-01

Sensors and active switches for applications in gas detection and other fields are described. The devices are based on the softening and hardening nonlinear response behaviors of microelectromechanical systems (MEMS) clamped-clamped microbeams

Modeling of municipal greenhouse gas emissions. Calculation of greenhouse gas emissions and the reduction possibilities of Dutch municipalities

NARCIS (Netherlands)

Vries de, Willem

2011-01-01

Summary Municipalities represent an active governmental layer in the Netherlands. They often have ambitions to reduce greenhouse gas emissions. In this way the municipalities take responsibility to reduce the threat of global warming. To implement effect

Futures trading and the storage of North American natural gas

Energy Technology Data Exchange (ETDEWEB)

Serletis, Apostolos; Shahmoradi, Asghar [Calgary Univ., Dept. of Economics, Calgary, AB (Canada)

2006-03-15

This paper tests the theory of storage in North American natural gas markets, using the Fama and French (1988) indirect test. In particular, we test the theory's prediction that when inventory is high, large inventory responses to shocks imply roughly equal changes in spot and futures prices, whereas when inventory is low, smaller inventory responses to shocks imply larger changes in spot prices than in futures prices. Our tests on spot and futures North American natural gas prices confirm these predictions of the theory of storage. (Author)

Metal-Organic Frameworks for Sensing Applications in the Gas Phase

Directory of Open Access Journals (Sweden)

Sabine Achmann

2009-03-01

Full Text Available Several metal-organic framework (MOF materials were under investigated to test their applicability as sensor materials for impedimetric gas sensors. The materials were tested in a temperature range of 120 °C - 240 °C with varying concentrations of O2, CO2, C3H8, NO, H2, ethanol and methanol in the gas atmosphere and under different test gas humidity conditions. Different sensor configurations were studied in a frequency range of 1 Hz -1 MHz and time-continuous measurements were performed at 1 Hz. The materials did not show any impedance response to O2, CO2, C3H8, NO, or H2 in the gas atmospheres, although for some materials a significant impedance decrease was induced by a change of the ethanol or methanol concentration in the gas phase. Moreover, pronounced promising and reversible changes in the electric properties of a special MOF material were monitored under varying humidity, with a linear response curve at 120 °C. Further investigations were carried out with differently doped MOF materials of this class, to evaluate the influence of special dopants on the sensor effect.

Glutamylation of the DNA sensor cGAS regulates its binding and synthase activity in antiviral immunity.

Science.gov (United States)

Xia, Pengyan; Ye, Buqing; Wang, Shuo; Zhu, Xiaoxiao; Du, Ying; Xiong, Zhen; Tian, Yong; Fan, Zusen

2016-04-01

Cyclic GMP-AMP synthase (cGAS) senses cytosolic DNA during viral infection and catalyzes synthesis of the dinucleotide cGAMP, which activates the adaptor STING to initiate antiviral responses. Here we found that deficiency in the carboxypeptidase CCP5 or CCP6 led to susceptibility to DNA viruses. CCP5 and CCP6 were required for activation of the transcription factor IRF3 and interferons. Polyglutamylation of cGAS by the enzyme TTLL6 impeded its DNA-binding ability, whereas TTLL4-mediated monoglutamylation of cGAS blocked its synthase activity. Conversely, CCP6 removed the polyglutamylation of cGAS, whereas CCP5 hydrolyzed the monoglutamylation of cGAS, which together led to the activation of cGAS. Therefore, glutamylation and deglutamylation of cGAS tightly modulate immune responses to infection with DNA viruses.

Preparation and Study of NH3 Gas Sensing Behavior of Fe2O3 Doped ZnO Thick Film Resistors

Directory of Open Access Journals (Sweden)

D. R. Patil

2006-08-01

Full Text Available The preparation, characterization and gas sensing properties of pure and Fe2O3-ZnO mixed oxide semiconductors have been investigated. The mixed oxides were obtained by mixing ZnO and Fe2O3 in the proportion 1:1, 1:0.5 and 0.5:1. Pure ZnO was observed to be insensitive to NH3 gas. However, mixed oxides (with ZnO: Fe2O3 =1:0.5 were observed to be highly sensitive to ammonia gas. Upon exposure to NH3 gas, the barrier height of Fe2O3-ZnO intergranular regions decreases markedly due to the chemical transformation of Fe2O3 into well conducting ferric ammonium hydroxide leading to a drastic decrease in resistance. The crucial gas response was found to NH3 gas at 3500C and no cross response was observed to other hazardous and polluting gases. The effects of microstructure and doping concentration on the gas response, selectivity, response and recovery of the sensor in the presence of NH3 gas were studied and discussed.

Comparison of Airway Responses Induced in a Mouse Model by the Gas and Particulate Fractions of Gasoline Direct Injection Engine Exhaust

Directory of Open Access Journals (Sweden)

Caitlin L. Maikawa

2018-03-01

Full Text Available Diesel exhaust has been associated with asthma, but its response to other engine emissions is not clear. The increasing prevalence of vehicles with gasoline direct injection (GDI engines motivated this study, and the objective was to evaluate pulmonary responses induced by acute exposure to GDI engine exhaust in an allergic asthma murine model. Mice were sensitized with an allergen to induce airway hyperresponsiveness or treated with saline (non-allergic group. Animals were challenged for 2-h to exhaust from a laboratory GDI engine operated at conditions equivalent to a highway cruise. Exhaust was filtered to assess responses induced by the particulate and gas fractions. Short-term exposure to particulate matter from GDI engine exhaust induced upregulation of genes related to polycyclic aromatic hydrocarbon (PAH metabolism (Cyp1b1 and inflammation (TNFα in the lungs of non-allergic mice. High molecular weight PAHs dominated the particulate fraction of the exhaust, and this response was therefore likely attributable to the presence of these PAHs. The particle fraction of GDI engine exhaust further contributed to enhanced methacholine responsiveness in the central and peripheral tissues in animals with airway hyperresponsiveness. As GDI engines gain prevalence in the vehicle fleet, understanding the health impacts of their emissions becomes increasingly important.

Comparison of Airway Responses Induced in a Mouse Model by the Gas and Particulate Fractions of Gasoline Direct Injection Engine Exhaust.

Science.gov (United States)

Maikawa, Caitlin L; Zimmerman, Naomi; Ramos, Manuel; Shah, Mittal; Wallace, James S; Pollitt, Krystal J Godri

2018-03-01

Diesel exhaust has been associated with asthma, but its response to other engine emissions is not clear. The increasing prevalence of vehicles with gasoline direct injection (GDI) engines motivated this study, and the objective was to evaluate pulmonary responses induced by acute exposure to GDI engine exhaust in an allergic asthma murine model. Mice were sensitized with an allergen to induce airway hyperresponsiveness or treated with saline (non-allergic group). Animals were challenged for 2-h to exhaust from a laboratory GDI engine operated at conditions equivalent to a highway cruise. Exhaust was filtered to assess responses induced by the particulate and gas fractions. Short-term exposure to particulate matter from GDI engine exhaust induced upregulation of genes related to polycyclic aromatic hydrocarbon (PAH) metabolism ( Cyp1b1 ) and inflammation ( TNFα ) in the lungs of non-allergic mice. High molecular weight PAHs dominated the particulate fraction of the exhaust, and this response was therefore likely attributable to the presence of these PAHs. The particle fraction of GDI engine exhaust further contributed to enhanced methacholine responsiveness in the central and peripheral tissues in animals with airway hyperresponsiveness. As GDI engines gain prevalence in the vehicle fleet, understanding the health impacts of their emissions becomes increasingly important.

Study of physical properties, gas generation and gas retention in simulated Hanford waste

International Nuclear Information System (INIS)

Bryan, S.A.; Pederson, L.R.; Scheele, R.D.

1993-04-01

The purpose of this study was to establish the chemical and physical processes responsible for the generation and retention of gases within high-level waste from Tank 101-SY on the Hanford Site. This research, conducted using simulated waste on a laboratory scale, supports the development of mitigation/remediation strategies for Tank 101-SY. Simulated waste formulations are based on actual waste compositions. Selected physical properties of the simulated waste are compared to properties of actual Tank 101-SY waste samples. Laboratory studies using aged simulated waste show that significant gas generation occurs thermally at current tank temperatures (∼60 degrees C). Gas compositions include the same gases produced in actual tank waste, primarily N 2 , N 2 O, and H 2 . Gas stoichiometries have been shown to be greatly influenced by several organic and inorganic constituents within the simulated waste. Retention of gases in the simulated waste is in the form of bubble attachment to solid particles. This attachment phenomenon is related to the presence of organic constituents (HEDTA, EDTA, and citrate) of the simulated waste. A mechanism is discussed that relates the gas bubble/particle interactions to the partially hydrophobic surface produced on the solids by the organic constituents

Oil and Gas Emergency Policy: Germany 2012 update

Energy Technology Data Exchange (ETDEWEB)

NONE

2012-07-01

Germany has very little domestic oil and natural gas production and relies heavily on imports. It has well diversified and flexible oil and natural gas supply infrastructure, which consists of crude, product and gas pipelines and crude and oil product import terminals. Natural gas is imported into Germany exclusively by cross-border pipeline. The country has no LNG infrastructure, although some German companies have booked capacities in overseas LNG terminals. Oil continues to be the main source of energy in Germany although it has declined markedly since the early 1970s. It now represents approximately 32% of Germany’s total primary energy supply (TPES). Natural gas consumption in Germany has declined 10% since 2006. Demand was 90 bcm in 2010, down from 100 bcm in 2005. According to government commissioned analysis, the total consumption of natural gas in Germany is expected to continue to decline over the long term. The share of natural gas in Germany’s TPES is currently around 22%. German oil stock levels are generally well above the required 90-days. Total oil stock levels in Germany were equivalent to 140 days net imports in April 2012. Since 1998, the German oil stockholding agency (EBV) has been solely responsible for meeting Germany's 90-day stockholding obligation. The Oil Stockholding Act stipulates that the EBV shall constantly maintain stocks of oil and petroleum products at a level equivalent to or above 90 days of net imports. There is no minimum stockholding obligation on industry, so industry held commercial stocks are held in addition to the EBV stocks. There are several legal tools available to German authorities for natural gas emergency response. These include Ordinances that can be used to restrict the sale, purchase or use of goods, both in terms of quantity and time, or permit them only for certain priority purposes, to ensure that vital energy needs are met. There are no compulsory natural gas storage requirements in Germany, and no

The Mexican energy sector: integrated dynamic analysis of the natural gas/refining system

International Nuclear Information System (INIS)

Barnes-Regueiro, Francisco; Leach, Matthew; Ruth, Matthias

2002-01-01

Environmental regulations in Mexico could dramatically increase demand for natural gas in the following years. This increase could lead to gas price shocks and a counter-intuitive increase in carbon emissions. The effect would be accentuated if Mexico lacks the funds required to carry on with investments in gas development and processing capacity. With the use of a dynamic computer model, this study addresses responses of the Mexican oil and gas industries to perturbations such as: changes in regulatory and environmental policies; changes in institutional arrangements such as those arising from market liberalization; and lack of availability of investment funds. The study also assesses how regulatory policies can be designed to minimize the economic inefficiencies arising from the business cycle disruptions that some perturbations may cause. In addition, this study investigates how investment responses will shape the Mexican energy sector in the future, particularly with respect to both the relative importance of different fuels for power generation and heating purposes and the nature of competition in the Mexican natural gas market. Furthermore, this study explores the direct consequences of these responses on the level of carbon emissions. (Author)

Accounting for gas in a de-regulated environment

International Nuclear Information System (INIS)

Zawalykut, P.M.

1992-01-01

Since the natural gas industry was deregulated, the method of buying, selling and moving gas has changed significantly. Post-deregulation, the pipeline company moves the gas but does not acquire ownership. The full impact of deregulation is seen in opening up the market for buying and selling gas. Tracking of gas has become critical. The service customer is now buying and moving gas. The end-use customer nominates to the distribution company a quantity of gas to be transported. Responsibility is placed on the customer to estimate loads as accurately as possible to avoid possible charges. The distribution company passes the end-user nomination to the upstream transmission company, which in turn passes it along, a process that is repeated until the nomination reaches the production company. Authorizations for gas follow a similar path. The major difference between sales and service gas is the accounting and tracking. As the customer will not consume the exact amount nominated, there will be an imblance between what was nominated and metered. There will also be imbalances between what the producer places into the pipeline and what was nominated. These processes can cause administrative problems, and many customers are moving from sales to service

Life-cycle greenhouse gas emissions of shale gas, natural gas, coal, and petroleum.

Science.gov (United States)

Burnham, Andrew; Han, Jeongwoo; Clark, Corrie E; Wang, Michael; Dunn, Jennifer B; Palou-Rivera, Ignasi

2012-01-17

The technologies and practices that have enabled the recent boom in shale gas production have also brought attention to the environmental impacts of its use. It has been debated whether the fugitive methane emissions during natural gas production and transmission outweigh the lower carbon dioxide emissions during combustion when compared to coal and petroleum. Using the current state of knowledge of methane emissions from shale gas, conventional natural gas, coal, and petroleum, we estimated up-to-date life-cycle greenhouse gas emissions. In addition, we developed distribution functions for key parameters in each pathway to examine uncertainty and identify data gaps such as methane emissions from shale gas well completions and conventional natural gas liquid unloadings that need to be further addressed. Our base case results show that shale gas life-cycle emissions are 6% lower than conventional natural gas, 23% lower than gasoline, and 33% lower than coal. However, the range in values for shale and conventional gas overlap, so there is a statistical uncertainty whether shale gas emissions are indeed lower than conventional gas. Moreover, this life-cycle analysis, among other work in this area, provides insight on critical stages that the natural gas industry and government agencies can work together on to reduce the greenhouse gas footprint of natural gas.

Spin Start Line Effects on the J2X Gas Generator Chamber Acoustics

Science.gov (United States)

Kenny, R. Jeremy

2011-01-01

The J2X Gas Generator engine design has a spin start line connected near to the turbine inlet vanes. This line provides helium during engine startup to begin turbomachinery operation. The spin start line also acts as an acoustic side branch which alters the chamber's acoustic modes. The side branch effectively creates 'split modes' in the chamber longitudinal modes, in particular below the first longitudinal mode and within the frequency range associated with the injection-coupled response of the Gas Generator. Interaction between the spin start-modified chamber acoustics and the injection-driven response can create a higher system response than without the spin start attached to the chamber. This work reviews the acoustic effects of the spin start line as seen throughout the workhorse gas generator test program. A simple impedance model of the spin start line is reviewed. Tests were run with no initial spin start gas existing in the line, as well as being initially filled with nitrogen gas. Tests were also run with varying spin start line lengths from 0" to 40". Acoustic impedance changes due to different spin start gas constituents and line lengths are shown. Collected thermocouple and static pressure data in the spin start line was used to help estimate the fluid properties along the line length. The side branch impedance model was coupled to a chamber impedance model to show the effects on the overall chamber response. Predictions of the spin start acoustic behavior for helium operation are shown and compared against available data.

Characteristic Value Method of Well Test Analysis for Horizontal Gas Well

Directory of Open Access Journals (Sweden)

Xiao-Ping Li

2014-01-01

Full Text Available This paper presents a study of characteristic value method of well test analysis for horizontal gas well. Owing to the complicated seepage flow mechanism in horizontal gas well and the difficulty in the analysis of transient pressure test data, this paper establishes the mathematical models of well test analysis for horizontal gas well with different inner and outer boundary conditions. On the basis of obtaining the solutions of the mathematical models, several type curves are plotted with Stehfest inversion algorithm. For gas reservoir with closed outer boundary in vertical direction and infinite outer boundary in horizontal direction, while considering the effect of wellbore storage and skin effect, the pseudopressure behavior of the horizontal gas well can manifest four characteristic periods: pure wellbore storage period, early vertical radial flow period, early linear flow period, and late horizontal pseudoradial flow period. For gas reservoir with closed outer boundary both in vertical and horizontal directions, the pseudopressure behavior of the horizontal gas well adds the pseudosteady state flow period which appears after the boundary response. For gas reservoir with closed outer boundary in vertical direction and constant pressure outer boundary in horizontal direction, the pseudopressure behavior of the horizontal gas well adds the steady state flow period which appears after the boundary response. According to the characteristic lines which are manifested by pseudopressure derivative curve of each flow period, formulas are developed to obtain horizontal permeability, vertical permeability, skin factor, reservoir pressure, and pore volume of the gas reservoir, and thus the characteristic value method of well test analysis for horizontal gas well is established. Finally, the example study verifies that the new method is reliable. Characteristic value method of well test analysis for horizontal gas well makes the well test analysis

Short-term Canadian natural gas deliverability 2006-2008 : an energy market assessment

International Nuclear Information System (INIS)

2006-10-01

This report presented an assessment of the expected capability of Canadian gas production through to the year 2008. Strong natural gas prices have led to record drilling levels in Canada's natural gas industry. North American natural gas prices reached a peak near the end of 2005. The rise in prices during 2005 reflected high world crude oil prices, a tight balance between natural gas supply and demand, and disruptions to United States gas supply from 2 hurricanes. In response to rising prices, western Canada drilling activity achieved new highs in early 2006. Higher drilling rates also reflected rising costs for key inputs of steel, fuel, and labour. Gas prices have since softened due to a storage overhang resulting from a mild winter. The combination of rising costs and softening prices has impacted margins for Canadian gas producers. In response, some producers have reduced drilling expansion plans in coalbed methane (CBM) and shallow gas plays in the Western Canadian Sedimentary Basin (WCSB). Increases in deeper gas drilling have been maintained. Total gas drilling for 2006 is expected to rise by 3 per cent compared to 2005. The report projected a small increase in Canada's total annual gas production from 484 million m 3 /d in 2005 to 491 million m 3 /d in 2008. Annual average deliverability of conventional gas is expected to decline slightly over the projection period. The decrease is expected to be more than offset by growth in CBM production in western Canada, which is expected to increase from 8 million m 3 /d in 2005 to 27 million m 3 /d in 2008. 5 tabs., 5 figs

Origin of natural gas; Tennen gas no kigen

Energy Technology Data Exchange (ETDEWEB)

Katayama, Y. [The Institute of Applied Energy, Tokyo (Japan)

1996-03-20

Natural gas, which is a general term of flammable hydrocarbon gases such as methane, is classified by origin into the following categories : (1) oil field gas (oil gas), (2) aquifers (bacteria-fermented methane), (3) coal gas (coal field gas), and (4) abiogenetic gas. The natural gas which has (1-4) origins and is now used as resource in a large quantity is (1) oil field gas. This gas is a hydrocarbon gas recovered in the production process of petroleum and contains components such as ethane, propane and butane. To the contrary, (2) aquifers and (3) coal gas have methane as main component. As (4) abiogenetic methane, there are gas formed in inorganic reaction in activities of submarine volcanos and deep gas (earth origin gas). Oil field gas has kerogen origin. Aquifers were formed by fermentation of organic matters. Coal gas was formed by coalification of vitrinite. As abiogenetic methane, there are inorganic reaction formation gas and deep gas, the latter of which exists little as resource. 7 refs., 11 figs., 1 tab.

Agricultural sources of greenhouse gas emissions

International Nuclear Information System (INIS)

Rochette, P.

2003-01-01

The author described different sources of greenhouse gas emissions resulting from agricultural activities and the process by which carbon dioxide, nitrous oxide, and methane are generated on Canadian farms. The author also proposed some practices that would contribute to the reduction of greenhouse gas emissions. A brief description of the greenhouse effect was also provided with special emphasis on the agricultural sector. In 1996, the Canadian agricultural sector was responsible for approximately 10 per cent of greenhouse gas emissions in the country. Given the increase in farm animals and more intensive agricultural activities, it is estimated that greenhouse gas emissions generated by the agricultural sector will increase by 20 per cent by 2010 if current practices remain in effect. The most optimistic scenarios indicate that the agricultural sector could achieve or even exceed Canada's Kyoto Protocol commitments mainly through organic material sequestration in soils. The possibility for farmers to sell greenhouse gas credits could motivate farmers into adopting various practices that reduce emissions of greenhouse gases. However, the author indicated that the best motivation for farmers is the fact that adopting such practices would also lead to more efficient agricultural production. 5 refs., 4 figs

Methanol Gas-Sensing Properties of SWCNT-MIP Composites

Science.gov (United States)

Zhang, Jin; Zhu, Qin; Zhang, Yumin; Zhu, Zhongqi; Liu, Qingju

2016-11-01

The single-walled carbon nanotube (SWCNT)-molecularly imprinted powder (MIP) composites in this paper were prepared by mixing SWCNTs with MIPs. The structure and micrograph of the as-prepared SWCNTs-MIPs samples were characterized by XRD and TEM. The gas-sensing properties were tested through indirect-heating sensors based on SWCNT-MIP composites fabricating on an alumina tube with Au electrodes and Pt wires. The results showed that the structure of SWCNTs-MIPs is of orthogonal perovskite and the average particle size of the SWCNTs-MIPs was in the range of 10-30 nm. SWCNTs-MIPs exhibit good methanol gas-sensitive properties. At 90 °C, the response to 1 ppm methanol is 19.7, and the response to the interferent is lower than 5 to the other interferent gases (ethanol, formaldehyde, toluene, acetone, ammonia, and gasoline). The response time and recovery time are 50 and 58 s, respectively.

Assisting Gas Optimization in CO2 Laser Welding

DEFF Research Database (Denmark)

Gong, Hui; Olsen, Flemming Ove

1996-01-01

High quality laser welding is achieved under the condition of optimizing all process parameters. Assisting gas plays an important role for sound welds. In the conventional welding process assisting gas is used as a shielding gas to prevent that the weld seam oxidates. In the laser welding process...... assisting gas is also needed to control the laser induced plasma.Assisting gas is one of the most important parameters in the laser welding process. It is responsible for obtaining a quality weld which is characterized by deep penetration, no interior imperfections, i.e. porosity, no crack, homogeneous seam...... surface, etc. In this work a specially designed flexible off-axis nozzle capable of adjusting the angle of the nozzle, the diameter of the nozzle, and the distance between the nozzle end and the welding zone is tested. In addition to the nozzle parameters three gases, Nitrogen, Argon, and Helium...

Surging electricity demand growth bolsters outlook for natural gas

International Nuclear Information System (INIS)

Koen, A.D.

1994-01-01

Economic expansion and regulatory reform are combining to boost global opportunities for burning gas to generate electric power. Companies producing, marketing, or transporting gas are capitalizing on the improved outlook by seizing on synergistic roles in the power generation chain. Much of the improved outlook for gas stems from projected hearty increases in global demand for electricity. Bechtel Power Corp., estimates global power generation capacity during 1994--2003 will increase to as much as 1.2 billion kw, about 25% of which could be added by independent power production (IPPs). Since about 200 bcf of gas reserves producing about 20 MMcfd of gas is needed to fuel of a 100,000 kw electric generating station for 25 years, that adds up to a major growth opportunity for gas producers. The paper discusses the assessment of gas reserves, US power growth, the intent of the Energy Policy Act of 1992 (Epact), effects of Epact, gas industry response, power marketing units, synergistic possibilities, effects on US utilities, international power imperatives, non-US projects, funding good projects, and forecasting future developments

Kinetic response study in chemiresistive gas sensor based on carbon nanotube surface functionalized with substituted phthalocyanines

Energy Technology Data Exchange (ETDEWEB)

Sharma, Anshul Kumar; Saini, Rajan; Bedi, R. K.; Mahajan, Aman, E-mail: dramanmahajan@yahoo.co.in, E-mail: anshulsharma.phy@gmail.com [Material Science Laboratory, Department of Physics, Guru Nanak Dev University, Amritsar 143005 (India); Kumar, Pankaj [Department of Applied Sciences, I.K. Gujral Punjab Technical University, Kapurthala 144601 (India)

2016-05-06

A kind of hybrid material is prepared by functionalizing multi-wall carbon nanotubes (MWCNTs-COOH) with substituted copper phthalocyanine and the formation of CuPcOC{sub 8}/MWCNTs-COOH hybrid is confirmed by scanning electron microscopy and transmission electron microscopy. The results indicated that on the surface of nanotubes substituted CuPcOC{sub 8} derivatives has been successfully anchored through π-π stacking interaction. The gas sensing application of the fabricated hybrid material is tested upon exposure to different hazardous species, specifically NO{sub 2}, NO, Cl{sub 2} and NH{sub 3} at operating temperature of 150°C. It has been demonstrated that for Cl{sub 2} minimum detection limit of CuPcOC{sub 8}/MWCNTs-COOH hybrid is 100 ppb. The response of hybrid sensor is found to be increased with increase in the concentration of Cl{sub 2}.

Nuclear Well Log Properties of Natural Gas Hydrate Reservoirs

Science.gov (United States)

Burchwell, A.; Cook, A.

2015-12-01

Characterizing gas hydrate in a reservoir typically involves a full suite of geophysical well logs. The most common method involves using resistivity measurements to quantify the decrease in electrically conductive water when replaced with gas hydrate. Compressional velocity measurements are also used because the gas hydrate significantly strengthens the moduli of the sediment. At many gas hydrate sites, nuclear well logs, which include the photoelectric effect, formation sigma, carbon/oxygen ratio and neutron porosity, are also collected but often not used. In fact, the nuclear response of a gas hydrate reservoir is not known. In this research we will focus on the nuclear log response in gas hydrate reservoirs at the Mallik Field at the Mackenzie Delta, Northwest Territories, Canada, and the Gas Hydrate Joint Industry Project Leg 2 sites in the northern Gulf of Mexico. Nuclear logs may add increased robustness to the investigation into the properties of gas hydrates and some types of logs may offer an opportunity to distinguish between gas hydrate and permafrost. For example, a true formation sigma log measures the thermal neutron capture cross section of a formation and pore constituents; it is especially sensitive to hydrogen and chlorine in the pore space. Chlorine has a high absorption potential, and is used to determine the amount of saline water within pore spaces. Gas hydrate offers a difference in elemental composition compared to water-saturated intervals. Thus, in permafrost areas, the carbon/oxygen ratio may vary between gas hydrate and permafrost, due to the increase of carbon in gas hydrate accumulations. At the Mallik site, we observe a hydrate-bearing sand (1085-1107 m) above a water-bearing sand (1107-1140 m), which was confirmed through core samples and mud gas analysis. We observe a decrease in the photoelectric absorption of ~0.5 barnes/e-, as well as an increase in the formation sigma readings of ~5 capture units in the water-bearing sand as

Papers of a Canadian Institute conference : Unconventional gas symposium : Tight gas, gas shales, coalbed methane, gas hydrates

International Nuclear Information System (INIS)

2003-01-01

This symposium provided an opportunity for participants to learn from gas industry leaders in both Canada and the United States, different strategies to cost-effectively develop unconventional gas resources. In particular, the representative from EnCana Corporation discussed the results of tight gas drilling in Northeastern British Columbia. The speaker for MGV Energy reported on the outcome of test drilling for coalbed methane (CBM) in Southern Alberta. The economic development of tight gas reservoirs in the United States Permian Basin was discussed by the speaker representing BP America Production Company. The role of unconventional gas in the North American natural gas supply and demand picture was dealt with by TransCanada PipeLines Limited and Canadian Gas Potential Committee. The trend for natural gas prices in North America was examined by Conoco Inc. The Geological Survey of Canada addressed the issue of gas hydrate potential in the Mackenzie Delta Mallik Field. In addition, one presentation by El Paso Production Company discussed the successful drilling for deep, tight gas and CBM in the United States. There were nine presentations at this symposium, of which three were indexed separately for inclusion in this database. refs., tabs., figs

Public safety and sour gas quarterly progress report October - December 2002

Energy Technology Data Exchange (ETDEWEB)

Sikora, V.; Lillo, H.; Craig, M.; Neilson, G.

2003-01-01

This third quarterly progress report for the business year 2002-2003 on the Alberta Energy and Utilities Board (EUB) Public Safety and Sour Gas initiative covers projects based on the 87 recommendations made by the Provincial Advisory Committee on Public Safety and Sour Gas (Advisory Committee) in December 2000. As of December 2002, work has been completed on 16 recommendations and is proceeding on 50 recommendations. This report includes several tables indicating the status of recommendations as either complete or ongoing. The recommendation categories include: (1) sour gas development, planning and approval, (2) sour gas operations, (3) emergency preparedness, and (4) information, communication and consultation. The report also summarizes the health effects and sour gas research. Recommendations completed as of December 2002 include: plant proliferation; pre-license review of critical well license applications; license application training/certification information requirement; increase sour gas inspections; increase inspections of new and noncompliant operators; implement 100 per cent inspection rate for critical wells near people; response to sour gas complaints; enhance EUB capability to monitor for complaint response/compliance; complaint/incident response program for Aboriginal communities; interim policy on ERP review and reduced EPZs; infrastructure and resources for Aboriginal community ERP; field staff in industry-landowner discussions; EUB involvement in mediation of application issues; and, timely and meaningful public consultation for First Nations and Metis. Alberta Health and Wellness is currently evaluating the health effects of H{sub 2}S and SO{sub 2} and the work is near completion. Other ongoing work includes the development of a draft protocol to address the involvement of regional health authorities (RHAs), the early involvement of RHAs and other local government bodies, and a process for communication between the EUB field staff and

Infrared spectroscopy for monitoring gas hydrates in aqueous solution

Energy Technology Data Exchange (ETDEWEB)

Dobbs, G.T.; Luzinova, Y.; Mizaikoff, B. [Georgia Inst. of Technology, Atlanta, GA (United States). School of Chemistry and Biochemistry; Raichlin, Y.; Katzir, A. [Tel-Aviv Univ., Tel-Aviv (Israel). Shool of Physics and Astronomy

2008-07-01

This paper introduced the first principles for monitoring gas hydrate formation and dissociation in aqueous solution by evaluating state-responsive infrared (IR) absorption features of water with fiberoptic evanescent field spectroscopy. A first order linear functional relationship was also derived according to Lambert Beer's law in order to quantify the percentage gas hydrate within the volume of water probed via the evanescent field. In addition, spectroscopic studies evaluating seafloor sediments collected from a gas hydrate site in the Gulf of Mexico revealed minimal spectral interferences from sediment matrix components. As such, evanescent field sensing strategies were established as a promising perspective for monitoring the dynamics of gas hydrates in oceanic environments. 21 refs., 5 figs.

The ocean's role in polar climate change: asymmetric Arctic and Antarctic responses to greenhouse gas and ozone forcing.

Science.gov (United States)

Marshall, John; Armour, Kyle C; Scott, Jeffery R; Kostov, Yavor; Hausmann, Ute; Ferreira, David; Shepherd, Theodore G; Bitz, Cecilia M

2014-07-13

In recent decades, the Arctic has been warming and sea ice disappearing. By contrast, the Southern Ocean around Antarctica has been (mainly) cooling and sea-ice extent growing. We argue here that interhemispheric asymmetries in the mean ocean circulation, with sinking in the northern North Atlantic and upwelling around Antarctica, strongly influence the sea-surface temperature (SST) response to anthropogenic greenhouse gas (GHG) forcing, accelerating warming in the Arctic while delaying it in the Antarctic. Furthermore, while the amplitude of GHG forcing has been similar at the poles, significant ozone depletion only occurs over Antarctica. We suggest that the initial response of SST around Antarctica to ozone depletion is one of cooling and only later adds to the GHG-induced warming trend as upwelling of sub-surface warm water associated with stronger surface westerlies impacts surface properties. We organize our discussion around 'climate response functions' (CRFs), i.e. the response of the climate to 'step' changes in anthropogenic forcing in which GHG and/or ozone-hole forcing is abruptly turned on and the transient response of the climate revealed and studied. Convolutions of known or postulated GHG and ozone-hole forcing functions with their respective CRFs then yield the transient forced SST response (implied by linear response theory), providing a context for discussion of the differing warming/cooling trends in the Arctic and Antarctic. We speculate that the period through which we are now passing may be one in which the delayed warming of SST associated with GHG forcing around Antarctica is largely cancelled by the cooling effects associated with the ozone hole. By mid-century, however, ozone-hole effects may instead be adding to GHG warming around Antarctica but with diminished amplitude as the ozone hole heals. The Arctic, meanwhile, responding to GHG forcing but in a manner amplified by ocean heat transport, may continue to warm at an accelerating rate.

Energy transition: the role of the gas vector

International Nuclear Information System (INIS)

Renard, Suzanne; Mazzega, Anthony

2013-01-01

GrDF (Gaz de France network Distribution) takes on all the responsibility functions - technical, industrial and legal - for a natural gas distribution network of almost 200 000 km, the most extensive in Europe. In the course of France's national debate on energy transition, GrDF presented its scenario out to 2050. One of its main conclusions: gas infrastructures can play a major role, accommodating new production, while ensuring solidarity between regions. (authors)

Novel gas sensors based on carbon nanotube networks

International Nuclear Information System (INIS)

Sayago, I; Aleixandre, M; Horrillo, M C; Fernandez, M J; Gutierrez, J; Terrado, E; Lafuente, E; Maser, W K; Benito, A M; Martinez, M T; Munoz, E; Urriolabeitia, E P; Navarro, R

2008-01-01