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Sample records for fissure type vents

  1. Phimosis with Preputial Fissures as a Predictor of Undiagnosed Type 2 Diabetes in Adults.

    PubMed

    Huang, Yun-Ching; Huang, Yao-Kuang; Chen, Chih-Shou; Shindel, Alan W; Wu, Ching-Fang; Lin, Jian-Hui; Chiu, Kuo-Hsiung; Yang, Tzu-Hsin; Shi, Chung-Sheng

    2016-03-01

    Diabetes is usually asymptomatic in its early stage. Early diagnosis may improve outcomes by enabling initiation of treatment before end organ damage has progressed. The aim of this study was to determine whether the clinical sign of phimosis with preputial fissures is predictive of type 2 diabetes in patients not previously diagnosed with diabetes. Twenty-eight patients with acquired phimosis and preputial fissures were collected prospectively. Twenty-eight controls with acquired phimosis without preputial fissures were selected. Statistically significant differences were found in body mass index, random plasma glucose, glucosuria and glycosylated haemoglobin levels, but not in age, family history of diabetes, hypertension and classical hyperglycaemic symptoms. Diabetes was confirmed in all 28 patients in the preputial fissures group, but only 2 (7.1%) patients in the non-preputial fissures group (p < 0.0001). In conclusion, phimosis with preputial fissures may be a specific sign of undiagnosed diabetes mellitus. PMID:26349852

  2. Relationships between lava types, seafloor morphology, and the occurrence of hydrothermal venting in the ASHES vent field of Axial Volcano. [Axial Seamount Hydrothermal Emission Study

    SciTech Connect

    Hammond, S.R. )

    1990-08-10

    Deep-towed and submersible photographic surveys within the caldera of Axial Volcano have been integrated with high-resolution bathmetry to produce a geological map of the most active vent field in the caldera. Locations for over 2,000 photographs in and near the vent field were determined using a seafloor transponder network. Then each photograph was described utilizing a classification system which provides detailed information concerning lava type, hydrothermal activity, sediment cover, geological structure, and biology. Resulting data were entered into a digital data base, and computer-generated maps were created that portray spatial relationships between selected geological variables. In general, the entire ASHES field is characterized by pervasive low-temperature venting. The most vigorous venting is concentrated in an approximately 80 m {times} 80 m area where there are several high-temperature vents including some which are producing high-temperature vapor-phase fluids derived from a boiling hydrothermal system. Lava types within the ASHES vent field are grouped into three distinct morphologies: (1) smooth (flat-surfaced, ropy, and whorled) sheet flows, (2) lobate flows, and (3) jumbled-sheet flows. The most intense hydrothermal venting is concentrated in the smooth sheet flows and the lobate flows. The location of the ASHES field is mainly attributable to faulting which defines the southwest caldera wall, but the concentration of intense venting appears to be related also to the spatial distribution of lava types in the vent field and their contrasting permeabilities. Other structural trends of faults and fissures within the field also influence the location of individual events.

  3. Submarine fissure eruptions and hydrothermal vents on the southern Juan de Fuca Ridge: preliminary observations from the submersible Alvin.

    USGS Publications Warehouse

    Normark, W.R.

    1986-01-01

    The submersible Alvin was used to investigate 3 active hydrothermal discharge sites along the S Juan de Fuca Ridge in September 1984. The hydrothermal zones occur within a 10-30m-deep, 30-50m-wide cleft marking the center of the axial valley. This cleft is the eruptive locus for the axial valley. The hydrothermal vents coincide with the main eruptive vents along the cleft. Each hydrothermal zone has multiple discharge sites extending as much as 500m along the cleft. Sulfide deposits occur as clusters (15-100m2 area) of small chimneys (= or <2m high) and as individual and clustered fields of large, branched chimneys (= or <10m high). Recovered sulfide samples are predominantly the tops of chimneys and spires and typically contain more than 80% sphalerite and wurtzite with minor pyrrhotite, pyrite, marcasite, isocubanite, chalcopyrite, anhydrite, anhydrite, and amorphous silica. The associated hydrothermal fluids have the highest chlorinity of any reported to date.-Authors

  4. Anal fissure.

    PubMed

    Metcalf, Amanda M

    2002-12-01

    Anal fissure is a common condition with a characteristic presentation. Despite increased pharmaceutical options in the medical management of anal fissures, surgical therapy is not in danger of becoming obsolete. Lateral internal sphincterotomy remains an attractive option for many patients suffering from this painful condition. PMID:12516855

  5. Anal fissure

    PubMed Central

    Schlichtemeier, Steven; Engel, Alexander

    2016-01-01

    SUMMARY An anal fissure is a common, mostly benign, condition that can be acute or chronic. The diagnosis is usually made on history and physical examination, but further investigations are sometimes necessary. Primary fissures are usually benign and located in the posterior or anterior position. Secondary fissures are lateral or multiple and often indicate a more serious underlying pathology. The management of primary anal fissures is generally non-operative and includes increased dietary fibre, sitz baths, topical ointments and botulinum toxin injections. If these treatments are ineffective the patient will need a surgical referral. Secondary anal fissures require further investigation. Multidisciplinary management is preferable and is essential in the case of malignancy. PMID:27041801

  6. Chabazite in spodumene-bearing Alpine-type fissure veins from Hiddenite, North Carolina, USA

    NASA Astrophysics Data System (ADS)

    Wise, Michael A.

    2009-07-01

    Alpine-type fissure vein mineralization in the Hiddenite area of western North Carolina, USA consists mostly of quartz, but locally contains Cr-bearing beryl (emerald) or Cr-bearing spodumene (hiddenite). These gem minerals occur in mineral-lined cavities and may be accompanied by euhedral crystals of quartz, calcite, muscovite, rutile, albite, pyrite, siderite and dolomite. Chabazite-Ca occurs as a late stage phase in spodumene-bearing veins, but is absent in emerald-bearing veins. Chabazite-Ca occurs as simple penetrating twins of pseudocubic rhombohedra and as the lens-shaped variety, phacolite. Chabazite-Ca from Hiddenite contains minor amounts of Na, Mg, Fe and K. Phacolitic chabazite-Ca shows Fe-enriched but Mg-depleted cores relative to the rims. Chemical zoning is absent in rhombohedral chabazite. The Hiddenite chabazite apparently precipitated under low temperature (< 250°C) and low pressure (< 2 kbar) conditions during the waning stages of crystallization of an alkaline hydrothermal fluid.

  7. Shallow Subsurface Structures of Volcanic Fissures

    NASA Astrophysics Data System (ADS)

    Parcheta, C. E.; Nash, J.; Mitchell, K. L.; Parness, A.

    2015-12-01

    Volcanic fissure vents are a difficult geologic feature to quantify. They are often too thin to document in detail with seismology or remote geophysical methods. Additionally, lava flows, lava drain back, or collapsed rampart blocks typically conceal a fissure's surface expression. For exposed fissures, quantifying the surface (let along sub0surface) geometric expression can become an overwhelming and time-consuming task given the non-uniform distribution of wall irregularities, drain back textures, and the larger scale sinuosity of the whole fissure system. We developed (and previously presented) VolcanoBot to acquire robust characteristic data of fissure geometries by going inside accessible fissures after an eruption ends and the fissure cools off to <50 C. Data from VolcanoBot documents the fissure conduit geometry with a near-IR structured light sensor, and reproduces the 3d structures to cm-scale accuracy. Here we present a comparison of shallow subsurface structures (<30 m depth) within the Mauna Ulu fissure system and their counterpart features at the vent-to-ground-surface interface. While we have not mapped enough length of the fissure to document sinuosity at depth, we see a self-similar pattern of irregularities on the fissure walls throughout the entire shallow subsurface, implying a fracture mechanical origin similar to faults. These irregularities are, on average, 1 m across and protrude 30 cm into the drained fissure. This is significantly larger than the 10% wall roughness addressed in the engineering literature on fluid dynamics, and implies that magma fluid dynamics during fissure eruptions are probably not as passive nor as simple as previously thought. In some locations, it is possible to match piercing points across the fissure walls, where the dike broke the wall rock in order to propagate upwards, yet in other locations there are erosional cavities, again, implying complex fluid dynamics in the shallow sub-surface during fissure eruptions.

  8. Anal fissure

    MedlinePlus

    ... pain interferes with normal bowel movements Petroleum jelly Zinc oxide, 1% hydrocortisone cream, Preparation H, and other ... anal muscle Prescription creams such as nitrates or calcium channel blockers, applied over the fissure to help ...

  9. Radar Observations of Fissure-fed Basaltic Lava Flows, Craters of the Moon, Idaho

    NASA Technical Reports Server (NTRS)

    Martel, L.; Greeley, R.

    1985-01-01

    Changes in surface roughness of lava flows, estimated from dual polarization, synthetic aperture, X and L band side-looking airborne radar images, were tested as a means of locating fissure vent areas. If lava textures proess from smooth, near-vent shelly pahoehoe to hummocky pahoehoe to aa with distance from fissure vents, then radr images of the lava flows would show a progression from dark to brighter tones due to the flows' increasing radar back-scatter.

  10. Radar observations of fissure-fed basaltic lava flows, Craters of the Moon, Idaho

    NASA Astrophysics Data System (ADS)

    Martel, L.; Greeley, R.

    1985-04-01

    Changes in surface roughness of lava flows, estimated from dual polarization, synthetic aperture, X and L band side-looking airborne radar images, were tested as a means of locating fissure vent areas. If lava textures proess from smooth, near-vent shelly pahoehoe to hummocky pahoehoe to aa with distance from fissure vents, then radr images of the lava flows would show a progression from dark to brighter tones due to the flows' increasing radar back-scatter.

  11. The architecture and shallow conduits of Laki-type pyroclastic cones: insights into a basaltic fissure eruption

    NASA Astrophysics Data System (ADS)

    Reynolds, P.; Brown, R. J.; Thordarson, T.; Llewellin, E. W.

    2016-05-01

    Pyroclastic cones built along basaltic fissures provide important volcanological information, but it is often difficult to examine the early-erupted products due to burial by later products. Furthermore, it is rare to see the link between the feeder dyke and overlying cone fully exposed. In this study, we detail the architecture of a hybrid spatter cone, scoria half-cone and feeder dyke that has been dissected to below the pre-eruption surface by glacial floods. The cones were constructed during the 6-8 ka Rauðuborgir-Kvensöðul fissure eruption in North Iceland during Hawaiian- and Strombolian-style activities. Widening of their feeder dyke in the shallow sub-surface to produce an upward flaring morphology was accommodated by country rock removal and elastic host rock deformation. Ballistic calculations and stratigraphic relationships indicate that the scoria half-cone was constructed early in the eruption from the deposits of a lava fountain ~100 m high. A decline in fountain height and the generation of abundant welded deposits resulted in the formation of a nested spatter cone within the scoria half-cone. The cones are similar in structure and size to the hybrid scoria and spatter cones produced during the 15-km3 1783 Laki eruption and serve as a valuable window into the construction of pyroclastic edifices during basaltic fissure eruptions.

  12. SURFACE FISSURE FORMATION ABOVE UNDERGROUND COALSEAM FIRES: DIMENSIONLESS RELATIONSHIPS BETWEEN SURFACE FISSURES AND SUBSURFACE SUBSIDENCE

    NASA Astrophysics Data System (ADS)

    Ide, T. S.; Pollard, D. D.; Orr, F. M.

    2009-12-01

    Coalbed fires are uncontrolled subsurface fires that occur around the world. These fires are believed to be significant contributors to annual CO2 emissions. Although many of these fires have been burning for decades, researchers have only recently begun to investigate physical mechanisms that control fire behavior. One aspect that is poorly characterized is the relationship between subsurface combustion and surface fissures. At the surface above many fires, long, wide fissures are observed. At a coalbed fire near Durango, Colorado, these fissures form systematic orthogonal patterns that align with regional joints in the Upper Cretaceous Fruitland Formation. Understanding the mechanisms that form and widen these fissures is important, as the fissures are believed to play vital roles in sustaining the combustion in the subsurface by acting as chimneys for the escaping gases and conduits for incoming oxygen. In some of the coalbed fire simulation models available today, these fissures are treated as fixed boundary conditions, but we argue, using field observations and simulation results, that there exists a relationship between the location and magnitude of subsidence caused by the fire and the opening of fissures. Four distinct types of fissures are observed over the coalbed fire near Durango, CO. These fissures are termed ‘molehill’, ‘plateau’, ‘gaping’, and ‘narrow’ based on their surface appearances. Molehill fissures are marked by surface depressions on either side, causing the strata around the opening to form an apex towards the center of the fissure. Plateau fissures show a steep vertical offset on only one side with minimal horizontal displacement. Gaping fissures and narrow fissures are predominantly opening with little evidence for vertical displacements. Gaping fissures are defined as fissures with wide apertures (0.3 ~ 1.5m), while narrow fissures have apertures on the order of centimeters. A boundary element method code was used to show

  13. Engineering a robotic approach to mapping exposed volcanic fissures

    NASA Astrophysics Data System (ADS)

    Parcheta, C. E.; Parness, A.; Mitchell, K. L.

    2014-12-01

    Field geology provides a framework for advanced computer models and theoretical calculations of volcanic systems. Some field terrains, though, are poorly preserved or accessible, making documentation, quantification, and investigation impossible. Over 200 volcanologists at the 2012 Kona Chapman Conference on volcanology agreed that and important step forward in the field over the next 100 years should address the realistic size and shape of volcanic conduits. The 1969 Mauna Ulu eruption of Kīlauea provides a unique opportunity to document volcanic fissure conduits, thus, we have an ideal location to begin addressing this topic and provide data on these geometries. Exposed fissures can be mapped with robotics using machine vision. In order to test the hypothesis that fissures have irregularities with depth that will influence their fluid dynamical behavior, we must first map the fissure vents and shallow conduit to deci- or centimeter scale. We have designed, constructed, and field-tested the first version of a robotic device that will image an exposed volcanic fissure in three dimensions. The design phase included three steps: 1) create the payload harness and protective shell to prevent damage to the electronics and robot, 2) construct a circuit board to have the electronics communicate with a surface-based computer, and 3) prototype wheel shapes that can handle a variety of volcanic rock textures. The robot's mechanical parts were built using 3d printing, milling, casting and laser cutting techniques, and the electronics were assembled from off the shelf components. The testing phase took place at Mauna Ulu, Kīlauea, Hawai'i, from May 5 - 9, 2014. Many valuable design lessons were learned during the week, and the first ever 3D map from inside a volcanic fissure were successfully collected. Three vents had between 25% and 95% of their internal surfaces imaged. A fourth location, a non-eruptive crack (possibly a fault line) had two transects imaging the textures

  14. Anal fissure - series (image)

    MedlinePlus

    ... rectum through which passes stool during defecation. The anal sphincter is a critical mechanism for control of ... Anal fissures are tears in the skin overlying the anal sphincter, usually due to increased tone of ...

  15. Anal fissure - slideshow

    MedlinePlus

    ... this page: //medlineplus.gov/ency/presentations/100154.htm Anal fissure - series—Normal anatomy To use the sharing ... rectum through which passes stool during defecation. The anal sphincter is a critical mechanism for control of ...

  16. A Geophysical Study of Fissures in Pahrump, Nevada

    NASA Astrophysics Data System (ADS)

    Hirsch, A. C.; McEwan, M. J.; Howley, R. A.; Mehling, J. B.; Snelson, C. M.; Drohan, P.

    2004-12-01

    Earth fissures are surface expressions of deep fracturing subsidence systems caused by groundwater withdrawl greater than aquifer recharge. This type of subsidence is most common in arid environments of the south western U.S. such as, Las Vegas, NV, Phoenix, AZ, and areas in New Mexico. In addition, fissures have recently been identified in the Pahrump Valley in southwestern Nevada just west of Las Vegas. The city of Pahrump has experienced an increase in population and economic growth. This growth has lead to a higher demand in the use of the areas natural resources. One major concern is groundwater pumping and over-watering of the land surface. Pahrump has experienced significant differential subsidence within the valley causing significant structural damage to infrastructure. This differential subsidence is most readily identified by its surface expression as fissures. Earth fissures are not only shallow surface features but can be 10's of meters deep and 100's of meters long. These ground failures can be exacerbated by faults at depth, shallow bedrock, and/or differential compaction. However, the most significant cause is from groundwater withdrawl. Several geophysical methods were performed on the fissures to better understand their subsurface expression, trend, and ultimately their affect on the city of Pahrump. Seismic refraction, reflection, ground penetrating radar (GPR), and gravity measurements were performed on the fissures and surrounding area including local faults. Our initial studies show the fissures propagating for long distances, in a variety of shapes, and trending in a north-south direction. Initial GPR studies show high fissure reflections at approximately 1 and 1.5 meters along with general slumping features below these reflections. Fissures are an unmitigatable problem. Our results will help identify fissures in the area that do not have a surface expression as well as mapping the current fissures and their extent. These results can be used

  17. High-Temperature Hydrothermal Vent Field of Kolumbo Submarine Volcano, Aegean Sea: Site of Active Kuroko-Type Mineralization

    NASA Astrophysics Data System (ADS)

    Sigurdsson, H.; Carey, S.; Alexandri, M.; Vougioukalakis, G.; Croff, K.; Roman, C.; Sakellariou, D.; Anagnostou, C.; Rousakis, G.; Ioakim, C.; Gogou, A.; Ballas, D.; Misaridis, T.; Nomikou, P.

    2006-12-01

    Kolumbo submarine volcano is located 7 km north-east of the island of Santorini in the Hellenic arc (Greece), and comprises one of about twenty submarine cones in a NE-trending rift zone. Kolumbo erupted explosively in 1649-50AD, causing 70 fatalities on Santorini. Kolumbo's crater is 1700 m in diameter, with a crater rim at 10 m below sea level and crater floor at depth of 505 m. Recent marine geological investigations, using ROVs, reveal a very active high-temperature hydrothermal vent field in the northeastern part of the Kolumbo crater floor, about 25,000 m2. Vent chimneys up to 4 m high are vigorously emitting colorless gas plumes up to 10 m high in the water column. Temperatures up to 220oC are recorded in vent fluids. Some vents are in crater- like depressions, containing debris from collapsed extinct chimneys. The entire crater floor of Kolumbo is mantled by a reddish-orange bacterial mat, and bacterial filaments of a variety of colors cling to chimneys in dense clusters. Glassy tunicates and anemones are common in lower-temperature environments on the crater floor. Most chimneys show a high porosity, with a central conduit surrounded by an open and very permeable framework of sulfides and sulfates, aiding fluid flow through the chimney walls. In the sulfate-rich samples, blades of euhedral barite and anhydrite crystals coat the outside of the chimney wall, and layers of barite alternate with sulfide in the interior. The dominant sulfides are pyrite, sphalerite, wurtzite, marcasite and galena. Crusts on extinct and lower-temperature chimneys are composed of amorphous silica, goethite and halite. Sulfur isotope composition of sulfates is virtually at sea water values, whereas the sulfides are more depleted. Elevated levels of copper, gold and silver are observed in bulk composition of chimney samples. Both the structural setting, character of the vent field and sulfide/sulfate mineralogy and geochemistry indicate on-going Kuroko-type mineralization in the

  18. Vents to events: determining an eruption event record from volcanic vent structures for the Harrat Rahat, Saudi Arabia

    NASA Astrophysics Data System (ADS)

    Runge, Melody G.; Bebbington, Mark S.; Cronin, Shane J.; Lindsay, Jan M.; Kenedi, Catherine L.; Moufti, Mohammed Rashad H.

    2014-03-01

    Distributed "monogenetic" volcanic eruptions commonly occur in continental settings without obvious structural alignments or rifting/extensional structures. Nevertheless, these may develop as fissures, representing the surface expression of dykes with a range of orientations, especially when stress regimes vary over time and/or older crustal features and faults are exploited by rising magmas. Dykes reaching the surface as fissures can last hours to months and produce groups of closely aligned vents, hiding the true extent of the source fissure. Grouped or aligned vents in a distributed volcanic environment add complexity to hazard modelling where the majority of eruptions are single-vent, point-source features, represented by cones, craters or domes; i.e. vent groups may represent fissure events, or single eruptions coincidently located but erupted hundreds to tens of thousands of years apart. It is common practice in hazard estimation for intraplate monogenetic volcanism to assume that a single eruption cone or crater represents an individual eruptive event, but this could lead to a significant overestimate of temporal recurrence rates if multiple-site and fissure eruptions were common. For accurate recurrence rate estimates and hazard-event scenarios, a fissure eruption, with its multiple cones, must be considered as a single multi-dimensional eruptive event alongside the single-vent eruptions. We present a statistical method to objectively determine eruptive events from visible vents, and illustrate this using the 968 vents of the 10 Ma to 0.6 ka volcanic field of Harrat Rahat, Saudi Arabia. A further method is presented to estimate the number of hidden vents in a thick volcanic pile. By combining these two methods for Harrat Rahat, we determined an updated spatial recurrence rate estimate, and an average temporal recurrence rate of 7.5 × 10-5 events/year. This new analysis highlights more concentrated regions of higher temporal hazard in parts of Harrat Rahat

  19. Video monitoring analysis of the dynamics at fissure eruptions

    NASA Astrophysics Data System (ADS)

    Witt, Tanja; Walter, Thomas R.

    2016-04-01

    At basaltic eruption often lava fountains occur. The fountains mainly develop at erupting fissures, underlain by a magma-filled dike transporting the magma horizontally and vertically. Understanding of the dynamics of the deep dike and fracture mechanisms are mainly based on geophysical data as well as observations from seismic or geodetic networks. At the surface, however, new methods are needed to allow detailed interpretation on the eruption velocities, interactions between vents and complexities in the magma paths. With video cameras we collected imaging data from different erupting fissures. We find that lava fountaining is often correlated at distinct vents. From the frames of the videos we calculated the height and velocities of fountains as a function of time. Lava fountains often show a pulsating regime, that may change over time. Comparing the fountain height as a function of time of different vents by an time-dependent cross-correlation, we find a time lag between the pulses at adjacent vents. From this we derive an apparent velocity of temporal separation between vents, associated with the fountaining activity based on the calculated time lag and the vent distances. Although the correlation system can change episodically and sporadically, both the frequency of the fountains and eruption and the rest time between single fountains remain remarkably similar for adjacent lava fountains imply a controlling process in the magma feeder system itself. We present and compare our method for the Kamoamoa eruption 2011 (Hawaii) and the Holuhraun eruption 2014/2015 (Iceland). Both sites show a significant time shift between the single pulses of adjacent vents. We compare our velocities determined by this time shift to the assumed magma flow velocity in the dike as determined by independent models. Therefore we conjecture that the time shift of venting activity may allow to estimate the dynamics of magma and fluid migration at depth, as well as to identify the

  20. New volcanogenic-eruptive genetic type of diamond occurrence (based on studying the 2012-2013 Fissure Tolbachik Eruption in Kamchatka)

    NASA Astrophysics Data System (ADS)

    Karpov, Gennady; Anikin, Leonid; Filatov, Stanislav; Silaev, Valery; Petrovsky, Vitaly; Zolotarev, Andrey; Dunin-Barkovsky, Romuald; Volynets, Anna

    2014-05-01

    During the 2012-2013 Fissure Tolbachik eruption, diamonds were found both in fresh pyroclastics and in the effusive lava pores. Lavas are aphyric and subaphyric porous aluminous basaltic trachyandesites with rare megacrysts and subphenocrysts of plagioclase, olivine and pyroxene. Groundmass is hyalopilitic, pilotaxitic, occasionally hyaline, with abundant plagioclase microlites. So far, over 750 diamond grains have been found sized mostly 100-500 mkm. Generally, grains are well formed isometric, plane-faced and sharp-edged monocrystals of cubic-octahedral habit and green color, rarer colorless. Faces of rhombic-dodecahedron, tetragonal-trisoctahedron and trigonal-trisoctahedron also occur. Crystal cubic faces host pits of diffusive depletion, and pits with induction surfaces formed after the breakoff of syngenetic inclusions. Octahedral faces often show pyramidal etching pits formed at the dislocation outcrops. Pits contain coatings whose composition includes Fe, Mg, Ca, Si, and Cu-Sn (Zn) alloy films. Diamond X-ray diffraction data (Bruker APEX DUO, STOE IPDS II, MoKα-radiation, 788 reflections) show space group Fd-3m, cubic unit cell parameter a = 3.574(3) A and major reflections (111), (220), (311) etc. at Gandolfi pattern. Raman spectra with red beam reveal only one strong line at 1332 cm-1 typical for diamonds. Spectra excited by the 785 nm beam reveal a wide line with the peak at 1370 cm-1, whose intensity oscillates from 1% to 70% of the diamond line intensity at 1332 cm-1. Infrared absorption spectra reflect two lines with peaks at 1345 and 1130 cm-1, corresponding to structural C-defects (isolated N atoms). Partially, these defects occur in the positive charge state - N+. Structural nitrogen concentration in the form of C-defects varies from 150 to 500 ppm, while that in the form of N+ - from 10 to 30 ppm. Lines of infrared absorption on A and B1 nitrogen defects, as well as those on hydrogen defects typical for most natural diamonds, are not detected for

  1. Growing Hemorrhagic Choroidal Fissure Cyst

    PubMed Central

    Gelal, Fazıl; Gurkan, Gokhan; Feran, Hamit

    2016-01-01

    Choroidal fissure cysts are often incidentally discovered. They are usually asymptomatic. The authors report a case of growing and hemorrhagic choroidal fissure cyst which was treated surgically. A 22-year-old female presented with headache. Cranial MRI showed a left-sided choroidal fissure cyst. Follow-up MRI showed that the size of the cyst had increased gradually. Twenty months later, the patient was admitted to our emergency department with severe headache. MRI and CT showed an intracystic hematoma. Although such cysts usually have a benign course without symptoms and progression, they may rarely present with intracystic hemorrhage, enlargement of the cyst and increasing symptomatology. PMID:26962426

  2. Vented transmission

    SciTech Connect

    Nguyen, T.H.

    1990-01-29

    This patent describes a vented transmission. It comprises: a housing; a rotary input to the housing; a rotary output from the housing; transmission means within the housing interconnecting the input and the output and including a hollow, rotary shaft journaled within the housing; a vent tube having a first end extending into one end of the hollow shaft and a second end in fluid communication with the exterior of the housing; a shoulder within the hollow shaft and intermediate the ends of the vent tube and defining of relatively smaller diameter section near the first end of the vent tube that is within the hollow shaft and a relatively large diameter section nearer the second end of the vent tube; at least one aperture extending through the hollow shaft from the large diameter section immediately adjacent the shoulder; and a labyrinth seal at the interface of the vent tube and the large diameter section at a location between the aperture (s) and the second end of the vent tube.

  3. Influence of Geologic Setting on the Morphology, Mineralogy, and Geochemistry of Vent Deposits Along the Eastern Lau Spreading Center and Valu Fa Ridge

    NASA Astrophysics Data System (ADS)

    Tivey, M. K.; Evans, G. N.; Ferrini, V. L.

    2014-12-01

    Establishment of links between lithology, vent fluid chemistry, and vent deposit characteristics along the Eastern Lau Spreading Center (ELSC) and Valu Fa Ridge (VFR) was made possible using deep submergence vehicles and technology. ROV Jason was used to collect ultrahigh-resolution (submeter) bathymetric data sufficient to quantify characteristics of volcanic, tectonic and hydrothermal features; differences within vent fields from north to south include a change from low-relief volcanic domes cut by faults and fissures to higher aspect ratio volcanic domes dominated by aa-type lava morphologies (Ferrini et al., G-cubed, 2008). Highest temperature fluids are associated with crosscutting faults at all but Mariner vent field where faults are not observed. The detailed maps were used to target areas within vent fields for observations and sampling. Vent deposit morphologies are similar at the northernmost vent fields (Kilo Moana, TowCam, Tahi Moana), with black smokers and diffusers present on branched edifices. Vent deposits at the more southerly ABE, Tui Malila and Mariner vent fields vary in morphology, despite similar substrate lithology. Examples include abundant flanges at ABE and Tui Malila and ~20m-tall spires and squat barite-rich edifices at Mariner. Geochemical analyses and petrographic observations document the influence of lithology, fluid temperature, pH, and extents of seawater mixing on deposit formation. Concentrations of As, which increase from north to south, reflect lithologic control. Sb, Pb, and Ba concentrations also reflect lithologic control, but are affected as well by low pH and/or extents of seawater mixing. The significant differences in Mariner deposits reflect formation from very high temperature, low pH (<3 vs >4) fluids that keep Zn in solution, combined with local subsurface mixing. Overall, results document the influence of the Tonga Subduction Zone on vent deposits through its affects on lithology and vent fluid composition.

  4. Direct Monte Carlo Simulations of Gas Flow from Enceladus’ Nozzle-like Vents

    NASA Astrophysics Data System (ADS)

    Tucker, Orenthal; Combi, M. R.; Tenishev, V.

    2013-10-01

    Collective observations by the Cassini spacecraft indicate that the gas plumes emanating from Enceladus’ south pole contain micrometer sized ice grains that travel at speeds 50-80% lower than the bulk gas speed (Kempf et al., 2008, Hedman et al., 2009, Teolis et al., 2010). Previous studies indicate the difference in velocity originates below the surface, and the gas flow to the surface occurs supersonically suggestive of nozzle like vents (Schmidt et al., 2008, Hansen et al., 2011). Here we use a 2D Direct Monte Carlo Simulation (DSMC) technique (Bird, 1994) to model gas flow and grain acceleration in nozzle like fissures for Enceladus’ vent geometries. First, we use the DSMC technique to model the transition of the gas flow from inside the highly collisional vent to a couple of meters above the surface where the gas flow becomes essentially collisionless. Then the DSMC results for gas density, temperature and velocity are used with an equation of motion for the drag force on a grain entrenched in a gas. The flow is tracked in both the vertical direction from the vent opening, and the radial direction from the vent axis. It is impossible to consider every type of vent geometry, but using Cassini data for grain sizes and velocities within the plumes we consider a few vent geometries of different width, length, and opening angle with respect to the surface. The Enceladus vents are not likely to be axially symmetric, but the simulations provide insight into possible vent geometries, and the effect of the vent wall geometry on gas flow and grain acceleration for suggested plume water production rates (0.5 - 1×1028 s-1) inferred using Cassini data (Tenishev et al., 2010). We obtain density and velocity distributions at the vent exit for the gas and grains that can serve as parameters for plume models and be used as comparisons for interpretation of various Cassini measurements. Kempf, S., et al., 2008, Icarus 193, 2. Hedman, M.M., et al., 2009, AJ 693. Teolis, B

  5. Vented Capacitor

    DOEpatents

    Brubaker, Michael Allen; Hosking, Terry Alan

    2006-04-11

    A technique of increasing the corona inception voltage (CIV), and thereby increasing the operating voltage, of film/foil capacitors is described. Intentional venting of the capacitor encapsulation improves the corona inception voltage by allowing internal voids to equilibrate with the ambient environment.

  6. Construction and Evolution of an Ice-Confined Basaltic Eruptive Fissure Complex: Sveifluhals, SW Iceland

    NASA Astrophysics Data System (ADS)

    Mercurio, E. C.; Skilling, I. P.; Cameron, B.

    2009-05-01

    Ice-confined fissure-fed basaltic eruptions were common in Iceland during the Pleistocene. Most of these generated complexes consisting of closely spaced, sub-parallel, multi-vent ridges. Individual ridges are constructed mostly of numerous linked steep-sided mounds (point-source vents) and short ridges (fissure vents) of subaqueous lavas, most of which are draped by phreatomagmatic tephra. There are more than 1000 such ridges in Iceland and they represent an important, largely untapped, database on North Atlantic terrestrial ice conditions. Some of these complexes were of comparable length to the famous Laki fissure eruptions of 1783-1785. Sveifluhals is a 21.5-km long formerly ice-confined fissure complex of unknown age, but similar nearby centers have been dated at about 47ka. Ice-thickness estimates, based on volatile analysis of pillow rind glass vary from 70-400m. This is the first detailed study of such a complex, which focuses on how it was constructed in space and time, how it differs from published studies of simple single short fissure ice-confined centers, and how it interacted with the overlying ice. Initial results have identified vents with an average spacing of 0.7km on at least nine sub-parallel fissures, which are spaced about 0.1-0.5km apart. The vents are dominated by inward and outward-dipping rotated (oversteepened) blocks of bedded tephra, which overlies mostly slumped massive tephra. The tephra drapes subaqueous lava mounds that display marginal steep- ridges of subaqueous lavas, that may have been emplaced in short sub-ice tunnels. We have also identified several now dry lakes that formed in some inter-ridge areas, but whose age relationship to ridge construction is as yet uncertain. We present here our preliminary data on vent locations and estimates of product volumes, volumes of ice melted, and location of possible meltwater pathways. We discuss the most important differences of the processes and products of such ridge complexes compared

  7. Research of features related to land subsidence and ground fissure disasters in the Beijing Plain

    NASA Astrophysics Data System (ADS)

    Yang, Y.; Luo, Y.; Liu, M.; Wang, R.; Wang, H.

    2015-11-01

    This study overviews the development history, current situation, impact, and hazards of land subsidence and ground fissure disasters in the Beijing Plain (BP) and focuses on the disaster distribution and features of disaster-causing mechanisms. Currently, the BP is still in a rapid developmental stage of land subsidence. The development and distribution of land subsidence are affected by various factors including the thickness of Quaternary compressible clay, groundwater overexploitation, and the rapid development of urban construction. The causes of ground fissures in the BP are complex and diverse, with evidence of structure fissures, non-structure fissures, and mixed genesis fissures. Investigations of the Gaoliying ground fissure have shown that this fissure has evidence of fracture activity, with vertical deformation that is more significant than horizontal deformation. Furthermore, this ground fissure has characteristics of inter-annual periodicity and annual jumping. The land subsidence and ground fissures are all under structural control and impact each other, and more severe hazards may be induced under the superimposition of these two types of disasters. Effective measures and suggestions for disaster prevention and control are recommended on the basis of this study.

  8. An opening magmatic fissure: structural pattern of its termination

    NASA Astrophysics Data System (ADS)

    Zelenin, Egor A.; Kozhurin, Andrey I.; Pinegina, Tatiana K.; Mikhaylyukova, Polina G.

    2014-05-01

    Volcanic zones of Kamchatka bear two types of active faults and fractures. Faults of the first type are tectonic, so they are long-living with net offset growing with time by repeating movement. Faults of the second type could be termed volcano-tectonic as they couple with or are caused by eruptions and thus move just once. Authors have explored and described a NE-SW-striking fissure on the SW side of Gorely plateau in the South Kamchatka volcanic zone, which conducted magma 200 years ago (Selyangin, Ponomareva, 1999). The fissure depression is filled with basaltic-andesite lava. The 900 meters long southern terminus of the fissure is situated on the hill slope and therefore not overlapped with lava. The fissure ending is an asymmetric graben, deeper at its west side, up to 300 m wide and bounded by two nearly parallel normal faults. The graben floor is gradually deepening to the north, away from the terminus, down to 9-10 m. Bounding faults are perfectly expressed in topography, thus providing a rare opportunity for determination of fissure parameters. Both faults dip at 80-85°, that gives approximately up to 3 m of perpendicular extension and the same thickness of the dyke beneath. Vertical movements on the western and eastern bounding faults were accompanied by horizontal components, left-lateral and right-lateral, respectively. There are also several transverse north-facing scarps breaking the graben floor and not extending beyond its limits. The observed deformations altogether suggests simultaneous sinking of the graben floor and northward compensating movement of masses into the graben. Tectonic landforms we studied illustrate how strain could be compensated at the end of an opening fissure and provide some insight into similar settings at a regional and even global scale.

  9. Microbial isotopic signatures in calcareous tufa from Punta Mita coastal vents, Mexico

    NASA Astrophysics Data System (ADS)

    Canet, C.; Prol-Ledesma, R. M.; Melgarejo, J. C.; Reyes, A.

    2002-12-01

    Numerous small calcareous mounds accompanied by Ba, Hg and Tl mineralization occur in shallow submarine hydrothermal manifestations on the sea bottom, at 10 m depth, in Punta Mita (Western coast of Mexico). The formation of calcite mounds in these coastal vents provides an uncommon example of calcareous tufa deposits in a submarine hydrothermal environment. The hydrothermal activity consists in water and gas (essentially nitrogen and methane) venting at 85°C, through a 100 m fissure hosted in basaltic rocks and partially covered by unconsolidated sediments. The mounds consist of travertine-like metre-sized calcite aggregates that develop around the main submarine hot springs. Barite, sulphides (mostly pyrite and cinnabar) and phosphates (carbonate-hydroxylapatite) are also present in these mounds. Two main calcite types are texturally distinguished: firstly an earlier radial-fibrous generation, and a later fine-grained calcite generation that cements the detrital grains and fills the pore spaces. Stable isotope analyses were performed in calcite from these mounds. The δ13C measured values show a strong depletion in 13C, with values as low as -39.2 per mil (PDB). These values agree with a microbially mediated calcite mineralization process, by means of bacterial oxidation of vent derived methane. In contrast to most known cases of microbial methane oxidation, in Punta Mita this process took place under hydrothermal conditions.

  10. Fluoride release from fissure sealants.

    PubMed

    Garcia-Godoy, F; Abarzua, I; De Goes, M F; Chan, D C

    1997-01-01

    This 30-day study, compared the amounts and patterns of fluoride release from 5 commercially available fluoride-containing pit and fissure sealants: FluroShield, Helioseal-F, Ultraseal XT, Baritone L3, and Teethmate-F; Delton without fluoride, was used as control. Disc-shaped samples of each sealant were immersed in distilled water and the fluoride release was measured periodically until day 30. All the fluoridated sealants tested released measurable fluoride throughout the test period in a similar pattern: the greatest amount of fluoride was released in the first 24 hours after mixing, fell sharply on the second day and decreased slowly for the last days. On day one, Baritone L3 released significantly more fluoride than all other materials. Teethmate-F released the highest amount of fluoride during all the other time intervals from day 2, until day 30. PMID:9643204

  11. Gas venting system

    SciTech Connect

    Khan, Amjad; Dreier, Ken Wayne; Moulthrop, Lawrence Clinton; White, Erik James

    2010-06-29

    A system to vent a moist gas stream is disclosed. The system includes an enclosure and an electrochemical cell disposed within the enclosure, the electrochemical cell productive of the moist gas stream. A first vent is in fluid communication with the electrochemical cell for venting the moist gas stream to an exterior of the enclosure, and a second vent is in fluid communication with an interior of the enclosure and in thermal communication with the first vent for discharging heated air to the exterior of the enclosure. At least a portion of the discharging heated air is for preventing freezing of the moist gas stream within the first vent.

  12. Anorectal conditions: anal fissure and anorectal fistula.

    PubMed

    Fox, Audralan; Tietze, Pamela H; Ramakrishnan, Kalyanakrishnan

    2014-04-01

    Anal fissures are linear splits in the anal mucosa. Acute fissures typically resolve within a few weeks; chronic fissures persist longer than 8 to 12 weeks. Most fissures are posterior and midline and are related to constipation or anal trauma. Painful defecation and rectal bleeding are common symptoms. The diagnosis typically is clinical. High-fiber diet, stool softeners, and medicated ointments relieve symptoms and speed healing of acute fissures but offer limited benefit in chronic fissures. Lateral internal sphincterotomy is the surgical management of choice for chronic and refractory acute fissures. Anorectal fistula is an abnormal tract connecting the anorectal mucosa to the exterior skin. Fistulas typically develop after rupture or drainage of a perianal abscess. Fistulas are classified as simple or complex; low or high; and intersphincteric, transsphincteric, suprasphincteric, or extrasphincteric. Inspection of the perianal area identifies the skin opening, and anoscopy visualizes internal openings. The goal of management is to obliterate the tract and openings with negligible sphincter disruption to minimize incontinence. Fistulotomy is effective for simple fistulas; patients with complex fistulas may require fistulectomy. Other procedures that are used include injection of fibrin glue or insertion of a bioprosthetic plug into the fistula opening. PMID:24742084

  13. A robotic approach to mapping post-eruptive volcanic fissure conduits

    NASA Astrophysics Data System (ADS)

    Parcheta, Carolyn E.; Pavlov, Catherine A.; Wiltsie, Nicholas; Carpenter, Kalind C.; Nash, Jeremy; Parness, Aaron; Mitchell, Karl L.

    2016-06-01

    VolcanoBot was developed to map volcanic vents and their underlying conduit systems, which are rarely preserved and generally inaccessible to human exploration. It uses a PrimeSense Carmine 1.09 sensor for mapping and carries an IR temperature sensor, analog distance sensor, and an inertial measurement unit (IMU) inside a protective shell. The first field test succeeded in collecting valuable scientific data but revealed several needed improvements, including more rugged cable connections and mechanical couplers, increased ground clearance, and higher-torque motors for uphill mobility. The second field test significantly improved on all of these aspects but it traded electrical ruggedness for reduced data collection speed. Data collected by the VolcanoBots, while intermittent, yield the first insights into the cm-scale geometry of volcanic fissures at depths of up to 25 m. VolcanoBot was deployed at the 1969 Mauna Ulu fissure system on Kīlauea volcano in Hawai'i. It collected first-of-its-kind data from inside the fissure system. We hypothesized that 1) fissure sinuosity should decrease with depth, 2) irregularity should be persistent with depth, 3) any blockages in the conduit should occur at the narrowest points, and 4) the fissure should narrow with depth until it is too narrow for VolcanoBot to pass or is plugged with solidified lava. Our field campaigns did not span enough lateral or vertical area to test sinuosity. The preliminary data indicate that 1) there were many irregularities along fissures at depth, 2) blockages occurred, but not at obviously narrow locations, and 3) the conduit width remained a consistent 0.4-0.5 m for most of the upper 10 m that we analyzed.

  14. 24 CFR 3280.611 - Vents and venting.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ...) Materials—(1) Pipe. Vent piping shall be standard weight steel, wrought iron, brass, copper tube DWV, listed... fittings shall conform to the type of piping used. (i) Fittings for screw pipe shall be cast iron, malleable iron, plastic, or brass, with standard pipe threads. (ii) Fittings for copper tubing shall be...

  15. Complete genome sequence of the aerobic, heterotroph Marinithermus hydrothermalis type strain (T1T) from a deep-sea hydrothermal vent chimney

    SciTech Connect

    Copeland, A; Gu, Wei; Yasawong, Montri; Lapidus, Alla L.; Lucas, Susan; Deshpande, Shweta; Pagani, Ioanna; Tapia, Roxanne; Cheng, Jan-Fang; Goodwin, Lynne A.; Pitluck, Sam; Liolios, Konstantinos; Ivanova, N; Mavromatis, K; Mikhailova, Natalia; Pati, Amrita; Chen, Amy; Palaniappan, Krishna; Land, Miriam L; Pan, Chongle; Brambilla, Evelyne-Marie; Rohde, Manfred; Tindall, Brian; Sikorski, Johannes; Goker, Markus; Detter, J. Chris; Bristow, James; Eisen, Jonathan; Markowitz, Victor; Hugenholtz, Philip; Kyrpides, Nikos C; Klenk, Hans-Peter; Woyke, Tanja

    2012-01-01

    Marinithermus hydrothermalis Sako et al. 2003 is the type species of the monotypic genus Marinithermus. M. hydrothermalis T1 T was the first isolate within the phylum ThermusDeinococcus to exhibit optimal growth under a salinity equivalent to that of sea water and to have an absolute requirement for NaCl for growth. M. hydrothermalis T1 T is of interest because it may provide a new insight into the ecological significance of the aerobic, thermophilic decomposers in the circulation of organic compounds in deep-sea hydrothermal vent ecosystems. This is the first completed genome sequence of a member of the genus Marinithermus and the seventh sequence from the family Thermaceae. Here we describe the features of this organism, together with the complete genome sequence and annotation. The 2,269,167 bp long genome with its 2,251 protein-coding and 59 RNA genes is a part of the Genomic Encyclopedia of Bacteria and Archaea project.

  16. Hemoglobins from deep-sea hydrothermal vent scaleworms of the genus Branchipolynoe: a new type of quaternary structure.

    PubMed

    Hourdez, S; Lallier, F H; Green, B N; Toulmond, A

    1999-03-01

    Branchipolynoe symmytilida and B. seepensis are two scaleworms (Polychaeta; Polynoidae) living commensally in the mantle cavity of deep-sea hydrothermal vent and cold-seep mussels. In contrast with littoral members of this family, the two species exhibit a large amount of extracellular hemoglobin (Hb) in their coelomic fluid. Gel filtration revealed the existence of four different Hbs: one minor, high molecular mass (3x10(6) Da) Hb, V1-Hb, reminiscent of a vascular hexagonal bilayer annelid Hb; two major coelomic Hbs, C1-Hb, and C2-Hb, with unusual masses for extracellular annelid Hbs of 153 and 124 kDa respectively; and a minor probably coelomic Hb of 23 kDa (C3-Hb). Using electrospray ionization mass spectrometry, SDS-PAGE after subtilisin treatment, and tandem mass spectrometry, we showed that C1-Hb is a trimer of a 57,996 Da chain and C2-Hb is a dimer of a 57,648 Da chain, each chain being a four-domain/four-heme polypeptide. This multimeric, multidomain arrangement is unique among annelid Hbs and appears different from that of other known multidomain Hbs. PMID:10081955

  17. Narrow Vertical Caves: Mapping Volcanic Fissure Geometries

    NASA Astrophysics Data System (ADS)

    Parcheta, C.; Nash, J.; Parness, A.; Mitchell, K. L.; Pavlov, C. A.

    2015-10-01

    Volcanic conduits are difficult to quantify, but their geometry fundamentally influences how eruptions occur. We robotically map old fissure conduits - elongated narrow cracks in the ground that transported magma to the surface during an eruption.

  18. Overview of the precursors and dynamics of the 2012-13 basaltic fissure eruption of Tolbachik Volcano, Kamchatka, Russia

    NASA Astrophysics Data System (ADS)

    Belousov, Alexander; Belousova, Marina; Edwards, Benjamin; Volynets, Anna; Melnikov, Dmitry

    2015-12-01

    We present a broad overview of the 2012-13 flank fissure eruption of Plosky Tolbachik Volcano in the central Kamchatka Peninsula. The eruption lasted more than nine months and produced approximately 0.55 km3 DRE (volume recalculated to a density of 2.8 g/cm3) of basaltic trachyandesite magma. The 2012-13 eruption of Tolbachik is one of the most voluminous historical eruptions of mafic magma at subduction related volcanoes globally, and it is the second largest at Kamchatka. The eruption was preceded by five months of elevated seismicity and ground inflation, both of which peaked a day before the eruption commenced on 27 November 2012. The batch of high-Al magma ascended from depths of 5-10 km; its apical part contained 54-55 wt.% SiO2, and the main body 52-53 wt.% SiO2. The eruption started by the opening of a 6 km-long radial fissure on the southwestern slope of the volcano that fed multi-vent phreatomagmatic and magmatic explosive activity, as well as intensive effusion of lava with an initial discharge of > 440 m3/s. After 10 days the eruption continued only at the lower part of the fissure, where explosive and effusive activity of Hawaiian-Strombolian type occurred from a lava pond in the crater of the main growing scoria cone. The discharge rate for the nine month long, effusion-dominated eruption gradually declined from 140 to 18 m3/s and formed a compound lava field with a total area of ~ 36 km2; the effusive activity evolved from high-discharge channel-fed 'a'a lavas to dominantly low-discharge tube-fed pahoehoe lavas. On 23 August, the effusion of lava ceased and the intra-crater lava pond drained. Weak Strombolian-type explosions continued for several more days on the crater bottom until the end of the eruption around 5 September 2013. Based on a broad array of new data collected during this eruption, we develop a model for the magma storage and transport system of Plosky Tolbachik that links the storage zones of the two main genetically related magma

  19. Short communication: sclerosing meningioma in the deep sylvian fissure.

    PubMed

    Fukushima, Shintaro; Narita, Yoshitaka; Yonezawa, Motoki; Ohno, Makoto; Arita, Hideyuki; Miyakita, Yasuji; Ichimura, Koichi; Yoshida, Akihiko; Shibui, Soichiro

    2014-10-01

    Sclerosing meningioma is a rare type of meningeal tumor with extensive collagen depositions. Deep sylvian meningioma, a tumor that is unattached to the dura mater, is also unusual. The biological activity of both is controversial, as are therapeutic strategies. A heterogeneous contrast-enhanced mass in the right sylvian fissure of a 10-year-old boy with a 3-year history of epilepsy was identified via magnetic resonance imaging. The patient underwent partial surgical resection because the tumor was hard and contained numerous perforators arising from the right middle cerebral artery. The tumor was histologically diagnosed as sclerosing meningioma. Twelve months after surgery, the patient was asymptomatic and did not require any additional therapies. This case is the first report of a sclerosing meningioma arising in the deep sylvian fissure. We discuss the therapeutic dilemma of this case with respect to the current literature. PMID:24141724

  20. Modeling plaque fissuring and dissection during balloon angioplasty intervention.

    PubMed

    Gasser, T Christian; Holzapfel, Gerhard A

    2007-05-01

    Balloon angioplasty intervention is traumatic to arterial tissue. Fracture mechanisms such as plaque fissuring and/or dissection occur and constitute major contributions to the lumen enlargement. However, these types of mechanically-based traumatization of arterial tissue are also contributing factors to both acute procedural complications and chronic restenosis of the treatment site. We propose physical and finite element models, which are generally useable to trace fissuring and/or dissection in atherosclerotic plaques during balloon angioplasty interventions. The arterial wall is described as an anisotropic, heterogeneous, highly deformable, nearly incompressible body, whereas tissue failure is captured by a strong discontinuity kinematics and a novel cohesive zone model. The numerical implementation is based on the partition of unity finite element method and the interface element method. The later is used to link together meshes of the different tissue components. The balloon angioplasty-based failure mechanisms are numerically studied in 3D by means of an atherosclerotic-prone human external iliac artery, with a type V lesion. Image-based 3D geometry is generated and tissue-specific material properties are considered. Numerical results show that in a primary phase the plaque fissures at both shoulders of the fibrous cap and stops at the lamina elastica interna. In a secondary phase, local dissections between the intima and the media develop at the fibrous cap location with the smallest thickness. The predicted results indicate that plaque fissuring and dissection cause localized mechanical trauma, but prevent the main portion of the stenosis from high stress, and hence from continuous tissue damage. PMID:17385047

  1. Testing Geyser Models using Down-vent Data

    NASA Astrophysics Data System (ADS)

    Wang, C.; Munoz, C.; Ingebritsen, S.; King, E.

    2013-12-01

    Geysers are often studied as an analogue to magmatic volcanoes because both involve the transfer of mass and energy that leads to eruption. Several conceptual models have been proposed to explain geyser eruption, but no definitive test has been performed largely due to scarcity of down-vent data. In this study we compare simulated time histories of pressure and temperature against published data for the Old Faithful geyser in the Yellowstone National Park and new down-vent measurements from geysers in the El Tatio geyser field of northern Chile. We test two major types of geyser models by comparing simulated and field results. In the chamber model, the geyser system is approximated as a fissure-like conduit connected to a subsurface chamber of water and steam. Heat supplied to the chamber causes water to boil and drives geyser eruptions. Here the Navier-Stokes equation is used to simulate the flow of water and steam. In the fracture-zone model, the geyser system is approximated as a saturated fracture zone of high permeability and compressibility, surrounded by rock matrix of relatively low permeability and compressibility. Heat supply from below causes pore water to boil and drives geyser eruption. Here a two-phase form of Darcy's law is assumed to describe the flow of water and steam (Ingebritsen and Rojstaczer, 1993). Both models can produce P-T time histories qualitatively similar to field results, but the simulations are sensitive to assumed parameters. Results from the chamber model are sensitive to the heat supplied to the system and to the width of the conduit, while results from the fracture-zone model are most sensitive to the permeability of the fracture zone and the adjacent wall rocks. Detailed comparison between field and simulated results, such as the phase lag between changes of pressure and temperature, may help to resolve which model might be more realistic.

  2. Fissure distribution at Mauna Loa (Hawaii) as an example to understand shallow magma transfer at volcanoes

    NASA Astrophysics Data System (ADS)

    La Marra, Daniele; Acocella, Valerio; Trusdell, Frank

    2016-04-01

    Mauna Loa (Hawaii) is the largest active shield volcano on the Island of Hawai'i, covering more than half of it and rising to 4,169 meters above sea level. The volcano hosts the Moku'aweoweo summit caldera, from which two elongated rift zones depart: the Northeast Rift Zone (NERZ) and the Southwest Rift Zone (SWRZ). Most of Mauna Loa's eruptions begin with lava fountains from a series of fissure vents in the summit region and then often migrate to vents down either rift zone. Mauna Loa volcano shows a distinctive feature, being characterized by minor radial eruptive fissures (not related to the two main rifts) on the NW flank only. This study tries to explain such a selective distribution of vents, and thus of shallow magma transfer. To this aim, we run numerical models with different amount of opening of the two rift zones of Mauna Loa, as well as different amount of slip on its SE flank. Our results suggest that the selective occurrence of the radial fissures may be explained by the competition between two processes: a) rift intrusion (especially along the NERZ), promoting the development of radial dikes along the NW flank; b) flank slip, inhibiting the development of the radial dikes on the SE flank. The opening of the two non-parallel main rift zones of Mauna Loa promotes the local extension necessary to develop the radial dikes on the NW flank. A general model for the development of a third branch of radial rift, which may be also applied to Mt. Etna and some volcanoes on the Canary Islands, is proposed.

  3. Hydrothermal vents of Yellowstone Lake, Yellowstone National Park, Wyoming

    SciTech Connect

    Kaplinski, M.A.; Morgan, P. . Geology Dept.)

    1993-04-01

    Hydrothermal vent systems within Yellowstone Lake are located within the Yellowstone caldera in the northeastern and West Thumb sections of the lake. The vent systems lie within areas of extremely high geothermal gradients (< 1,000 C/km) in the lake sediments and occur as clusters of individual vents that expel both hydrothermal fluids and gas. Regions surrounding the vents are colonized by unique, chemotropic biologic communities and suggest that hydrothermal input plays an important role in the nutrient dynamics of the lake's ecosystem. The main concentration of hydrothermal activity occurs in the northeast region of the main lake body in a number of locations including: (1) along the shoreline from the southern edge of Sedge Bay to the inlet of Pelican Creek; (2) the central portion of the partially submerged Mary Bay phreatic explosion crater, within deep (30--50 m) fissures; (3) along the top of a 3 km long, steep-sided ridge that extends from the southern border of Mary Bay, south-southeast into the main lake basin; and (4) east of Stevenson Island along the lower portion of the slope (50--107 m) into the lake basin, within an anastomosing series of north to northwest trending, narrow troughs or fissures. Hydrothermal vents were also located within, and surrounding the West Thumb of Yellowstone Lake, with the main concentration occurring the offshore of the West Thumb and Potts Geyser Basin. Hydrothermal vents in Yellowstone Lake occur along fractures that have penetrated the lake sediments or along the tops of ridges and near shore areas. Underneath the lake, rising hydrothermal fluids encounter a semi-permeable cap of lake sediments. Upwardly convecting hydrothermal fluid flow may be diverted by the impermeable lake sediments along the buried, pre-existing topography. These fluids may continue to rise along topography until fractures are encountered, or the lake sediment cover is thinned sufficiently to allow egress of the fluids.

  4. Robust pulmonary lobe segmentation against incomplete fissures

    NASA Astrophysics Data System (ADS)

    Gu, Suicheng; Zheng, Qingfeng; Siegfried, Jill; Pu, Jiantao

    2012-03-01

    As important anatomical landmarks of the human lung, accurate lobe segmentation may be useful for characterizing specific lung diseases (e.g., inflammatory, granulomatous, and neoplastic diseases). A number of investigations showed that pulmonary fissures were often incomplete in image depiction, thereby leading to the computerized identification of individual lobes a challenging task. Our purpose is to develop a fully automated algorithm for accurate identification of individual lobes regardless of the integrity of pulmonary fissures. The underlying idea of the developed lobe segmentation scheme is to use piecewise planes to approximate the detected fissures. After a rotation and a global smoothing, a number of small planes were fitted using local fissures points. The local surfaces are finally combined for lobe segmentation using a quadratic B-spline weighting strategy to assure that the segmentation is smooth. The performance of the developed scheme was assessed by comparing with a manually created reference standard on a dataset of 30 lung CT examinations. These examinations covered a number of lung diseases and were selected from a large chronic obstructive pulmonary disease (COPD) dataset. The results indicate that our scheme of lobe segmentation is efficient and accurate against incomplete fissures.

  5. Outpatient treatment of fissure-in-ano.

    PubMed

    Badejo, O A

    1984-12-01

    A review of 86 cases of fissure-in-ano as seen in Ife is presented. The method of management is described and compared with other conservative methods of treatment. The results show a complete healing of the condition within two weeks as compared with four to six weeks recorded in other series. Healing was confirmed by a complete resolution of symptoms together with re-epithelisation of the fissure on inspection at proctoscopy. It is suggested that the described surgical management is simple, fast, cost reducing and time saving in the treatment of fissure-in-ano. It is further envisaged that this procedure may also serve as a means of relief to our already congested hospitals. PMID:6528355

  6. Effect of surface fissure on apparent resistivity measurements

    NASA Astrophysics Data System (ADS)

    Sailhac, P.; Gance, J.; Malet, J.

    2013-12-01

    Fissures are features of interest, prone to create preferential flow path, modifying locally the soil hydrogeological behavior. Electrical Resistivity Tomography (ERT) is a suitable tool to monitor such preferential flow path. However, this technique is not efficient in the presence of surface fissure, due to a bad resistivity recovering around the fissure vicinity during the inversion process. Therefore, we propose a description of fissure effect on raw apparent resistivity on three resistivity arrays. The purposes of the study are multiple. First, we aim at making ERT users aware of surface fissure effect, and propose a first help to interpret basically resistivity pseudo sections. Second, we propose to ERT users to automatically conduct a surface fissure survey on the studied profile, in order to consider each fissure in a forward DC model and to suppress their effect. Finally, this study is only a first step toward 2D fissure shape inversion, and time-lapse monitoring of fissure drying and filling. In this study, we create a fissure model based on different geomorphological descriptors. After describing the FEM-DC forward modeling strategy, we investigate the fissure effect on pseudo section of apparent resistivity for a Wenner-Schlumberger (WS), a dipole-dipole (DD) and a gradient (GRAD) array. We determine a fissure detectability threshold for each array and perform a sensitivity analysis on the different fissure parameters (position, width, depth, dip angles...). The crack filling or drying effect is also investigated. The possibility to remove fissure effect and to propose a first interpretation of time-lapse data is illustrated on real data. This study show again the higher sensitivity of the DD array compared to the GRAD and WS arrays. Not only the maximal amplitude in the pseudo section is higher for the DD array, but also the anomaly pattern created by the fissure is much larger for this acquisition geometry. The minimal depth detectable for the DD

  7. Thoracoscopic sympathetic clamping in a patient with an azygos fissure.

    PubMed

    Moon, Seok Whan; Yoon, Jeong Sub; Jo, Keon Hyeon; Wang, Young Pil; Park, Hyeon Jin

    2005-04-01

    We believe that an azygos fissure may predispose to bleeding during thoracoscopic surgery. An azygos fissure causes important morphologic changes in the superior mediastinum and thereby poses a risk of massive bleeding during thoracoscopic procedures. We report on a successful thoracoscopic procedure conducted in a patient with palmar hyperhidrosis and an azygos fissure and emphasize that the course of the thoracic sympathetic chain runs laterally along the base of the azygos fissure. PMID:15821627

  8. Geochemistry of the 2012-2013 Tolbachik Fissure eruption (Kamchatka, Russia)

    NASA Astrophysics Data System (ADS)

    Volynets, Anna; Melnikov, Dmitry; Belousov, Alexander; Belousova, Marina; Yakushev, Anton

    2014-05-01

    From November 27th, 2012, until the beginning of September 2013, a fissure eruption at the southern slope of Ploskiy Tolbachik volcano, Kamchatka, produced more than 0.52 km3 of lava (Dvigalo et al., 2014) and covered the area about 36 km2. The eruption was named as "The Institute of Volcanology and Seismology 50th Anniversary Fissure Tolbachik Eruption" (FTE-50). This is a manifestation of the ongoing high activity in Tolbachinskiy Dol (monogenetic zone around Ploskiy Tolbachik stratovolcano), which already produced in Holocene a lava field, covering more than 900 km2. FTE-50 lasted 9 months and exhibited some peculiar features, allowing us to distinguish it as a unique for Tolbachinskiy Dol: seismic activity only in the low energy class during 5 month prior to eruption (Kugaenko et al., 2013), the unusually high discharge rate at the beginning of the eruption (about 400 m3/sec), specific geochemical composition of the erupted lava. The eruption started from two vents, named after eminent Russian volcanologists as Menyailov (upper) and Naboko (lower) vents, and after three days all activity concentrated in the lower (Naboko) vent. All products of FTE-50 are richer in alkalis and TiO2 than previously studied lavas of Tolbachinskiy Dol. After the drastic change in composition at the beginning of the eruption, associated with the shift of the eruption center from the Menyailov to Naboko vent, when silica content dropped up to 2 wt.%, the composition remained practically constant until at least May 2013. Lavas of the Menyailov Vent are more acid than any of the earlier erupted rocks of the monogenetic zone (SiO2 up to 55.35 wt.%). Lavas of the Naboko Vent, at silica content close to the Southern Vent of the Great Fissure Tolbachik Eruption (1975-76) and other alumina-rich basaltic andesites of the Dol (52.5 wt.% in average in Naboko vent lavas vs. 51.8 wt.% in high-Al lavas from Tolb.Dol), have lowered concentrations of Al2O3 (16.3 wt.% vs. 17.1 wt/%), CaO (7.5 wt

  9. Battery venting system and method

    DOEpatents

    Casale, Thomas J.; Ching, Larry K. W.; Baer, Jose T.; Swan, David H.

    1999-01-05

    Disclosed herein is a venting mechanism for a battery. The venting mechanism includes a battery vent structure which is located on the battery cover and may be integrally formed therewith. The venting mechanism includes an opening extending through the battery cover such that the opening communicates with a plurality of battery cells located within the battery case. The venting mechanism also includes a vent manifold which attaches to the battery vent structure. The vent manifold includes a first opening which communicates with the battery vent structure opening and second and third openings which allow the vent manifold to be connected to two separate conduits. In this manner, a plurality of batteries may be interconnected for venting purposes, thus eliminating the need to provide separate vent lines for each battery. The vent manifold may be attached to the battery vent structure by a spin-welding technique. To facilitate this technique, the vent manifold may be provided with a flange portion which fits into a corresponding groove portion on the battery vent structure. The vent manifold includes an internal chamber which is large enough to completely house a conventional battery flame arrester and overpressure safety valve. In this manner, the vent manifold, when installed, lessens the likelihood of tampering with the flame arrester and safety valve.

  10. Battery venting system and method

    DOEpatents

    Casale, T.J.; Ching, L.K.W.; Baer, J.T.; Swan, D.H.

    1999-01-05

    Disclosed herein is a venting mechanism for a battery. The venting mechanism includes a battery vent structure which is located on the battery cover and may be integrally formed therewith. The venting mechanism includes an opening extending through the battery cover such that the opening communicates with a plurality of battery cells located within the battery case. The venting mechanism also includes a vent manifold which attaches to the battery vent structure. The vent manifold includes a first opening which communicates with the battery vent structure opening and second and third openings which allow the vent manifold to be connected to two separate conduits. In this manner, a plurality of batteries may be interconnected for venting purposes, thus eliminating the need to provide separate vent lines for each battery. The vent manifold may be attached to the battery vent structure by a spin-welding technique. To facilitate this technique, the vent manifold may be provided with a flange portion which fits into a corresponding groove portion on the battery vent structure. The vent manifold includes an internal chamber which is large enough to completely house a conventional battery flame arrester and overpressure safety valve. In this manner, the vent manifold, when installed, lessens the likelihood of tampering with the flame arrester and safety valve. 8 figs.

  11. Battery Vent Mechanism And Method

    DOEpatents

    Ching, Larry K. W.

    2000-02-15

    Disclosed herein is a venting mechanism for a battery. The venting mechanism includes a battery vent structure which is located on the battery cover and may be integrally formed therewith. The venting mechanism includes an opening extending through the battery cover such that the opening communicates with a plurality of battery cells located within the battery case. The venting mechanism also includes a vent manifold which attaches to the battery vent structure. The vent manifold includes a first opening which communicates with the battery vent structure opening and second and third openings which allow the vent manifold to be connected to two separate conduits. In this manner, a plurality of batteries may be interconnected for venting purposes, thus eliminating the need to provide separate vent lines for each battery. The vent manifold may be attached to the battery vent structure by a spin-welding technique. To facilitate this technique, the vent manifold may be provided with a flange portion which fits into a corresponding groove portion on the battery vent structure. The vent manifold includes an internal chamber which is large enough to completely house a conventional battery flame arrester and overpressure safety valve. In this manner, the vent manifold, when installed, lessens the likelihood of tampering with the flame arrester and safety valve.

  12. Payload bay atmospheric vent airflow testing at the Vibration and Acoustic Test Facility

    NASA Technical Reports Server (NTRS)

    Johnston, James D., Jr.

    1988-01-01

    Several concerns related to venting the Space Shuttle Orbiter payload bay during launch led to laboratory experiments with a flight-type vent box installed in the wall of a subsonic wind tunnel. This report describes the test setups and procedures used to acquire data for characterization of airflow through the vent box and acoustic tones radiated from the vent-box cavity. A flexible boundary-layer spoiler which reduced the vent-tone amplitude is described.

  13. Multiple I-Type Lysozymes in the Hydrothermal Vent Mussel Bathymodiolus azoricus and Their Role in Symbiotic Plasticity

    PubMed Central

    Detree, Camille; Chabenat, Apolline; Lallier, François H.; Satoh, Nori; Shoguchi, Eiichi; Tanguy, Arnaud; Mary, Jean

    2016-01-01

    The aim of this study was first to identify lysozymes paralogs in the deep sea mussel Bathymodiolus azoricus then to measure their relative expression or activity in different tissue or conditions. B. azoricus is a bivalve that lives close to hydrothermal chimney in the Mid-Atlantic Ridge (MAR). They harbour in specialized gill cells two types of endosymbiont (gram—bacteria): sulphide oxidizing bacteria (SOX) and methanotrophic bacteria (MOX). This association is thought to be ruled by specific mechanism or actors of regulation to deal with the presence of symbiont but these mechanisms are still poorly understood. Here, we focused on the implication of lysozyme, a bactericidal enzyme, in this endosymbiosis. The relative expression of Ba-lysozymes paralogs and the global anti-microbial activity, were measured in natural population (Lucky Strike -1700m, Mid-Atlantic Ridge), and in in situ experimental conditions. B. azoricus individuals were moved away from the hydrothermal fluid to induce a loss of symbiont. Then after 6 days some mussels were brought back to the mussel bed to induce a re-acquisition of symbiotic bacteria. Results show the presence of 6 paralogs in B. azoricus. In absence of symbionts, 3 paralogs are up-regulated while others are not differentially expressed. Moreover the global activity of lysozyme is increasing with the loss of symbiont. All together these results suggest that lysozyme may play a crucial role in symbiont regulation. PMID:26882089

  14. Multiple I-Type Lysozymes in the Hydrothermal Vent Mussel Bathymodiolus azoricus and Their Role in Symbiotic Plasticity.

    PubMed

    Detree, Camille; Chabenat, Apolline; Lallier, François H; Satoh, Nori; Shoguchi, Eiichi; Tanguy, Arnaud; Mary, Jean

    2016-01-01

    The aim of this study was first to identify lysozymes paralogs in the deep sea mussel Bathymodiolus azoricus then to measure their relative expression or activity in different tissue or conditions. B. azoricus is a bivalve that lives close to hydrothermal chimney in the Mid-Atlantic Ridge (MAR). They harbour in specialized gill cells two types of endosymbiont (gram-bacteria): sulphide oxidizing bacteria (SOX) and methanotrophic bacteria (MOX). This association is thought to be ruled by specific mechanism or actors of regulation to deal with the presence of symbiont but these mechanisms are still poorly understood. Here, we focused on the implication of lysozyme, a bactericidal enzyme, in this endosymbiosis. The relative expression of Ba-lysozymes paralogs and the global anti-microbial activity, were measured in natural population (Lucky Strike--1700 m, Mid-Atlantic Ridge), and in in situ experimental conditions. B. azoricus individuals were moved away from the hydrothermal fluid to induce a loss of symbiont. Then after 6 days some mussels were brought back to the mussel bed to induce a re-acquisition of symbiotic bacteria. Results show the presence of 6 paralogs in B. azoricus. In absence of symbionts, 3 paralogs are up-regulated while others are not differentially expressed. Moreover the global activity of lysozyme is increasing with the loss of symbiont. All together these results suggest that lysozyme may play a crucial role in symbiont regulation. PMID:26882089

  15. 24 CFR 3280.611 - Vents and venting.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... vent pipe or equivalent directly connected to the toilet drain within the distance allowed in § 3280... any other vent pipe. Vents for horizontal drains shall connect above the centerline of the drain... this section and as otherwise required by this standard. (b) Materials—(1) Pipe. Vent piping shall...

  16. 24 CFR 3280.611 - Vents and venting.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... for all changes in direction or size and where pipes are joined. The material and design of vent...) Size of vent piping—(1) Main vent. The drain piping for each toilet shall be vented by a 11/2 inch... toilet drain within the distance allowed in § 3280.611(c)(5), for 3-inch trap arms undiminished in...

  17. Dynamics of the 2014 Holuhraun fissure eruption analysed by video monitoring system

    NASA Astrophysics Data System (ADS)

    Witt, Tanja; Walter, Thomas R.

    2015-04-01

    Events on the volcanic system within the axial volcanic zones are linked to plate movements. The spreading and subsequent rifting of the crust take place at the plate boundary and occurs in distinct rifting episodes. These rifting episodes are characterized by earthquakes and volcanic eruptions within the central volcano or along fissures. For the subsurface structure of a volcanic system and the behavior of the magma plumbing system during major rifting episodes two contrasting models exists, (i) vertical feeding by a deep magma source or (ii) lateral feeding through a shallow magma chamber under the central volcano. The ongoing 2014 Holuhraun eruption is providing a unique opportunity to rigorously test the feeding paths of an active fissure eruption. Here we employ video images to analyse the height and velocity variation of the lava fountains at the Holuhraun eruption fissure. On the first day of the eruption we could set up in total five high resolution video cameras. With algorithms of photogrammetry and correlation analysis we interpret the behavior of the lava fountains. Results suggest a significal lateral propagation path of the dynamics of the active vents, and a lateral migration of the peaks and lows of distinct lava fountains. Although the correlation system can change episodically and sporadically, both the frequency of the lava fountains and the eruption and rest time between single fountains remain similar for adjacent lava fountains imply a controlling process in the magma feeder system itself. We interpret the results by a lateral magma and gas flow underlying and feeding the eruption fissure. Systematic recording and analysis of video data hence help to decide which magma plumbing system is more reliable. Additionally, the dataset allows us to compare the eruption behavior to seismic datasets.

  18. From fissure to fault: A model of fault growth in the Krafla Fissure System, NE Iceland

    NASA Astrophysics Data System (ADS)

    Bramham, Emma; Paton, Douglas; Wright, Tim

    2015-04-01

    Current models of fault growth examine the relationship of fault length (L) to vertical displacement (D) where the faults exhibit the classic fault shape of gradually increasing vertical displacement from zero at the fault tips to a maximum displacement (Dmax) at the middle of the fault. These models cannot adequately explain displacement-length observations at the Krafla fissure swarm, in Iceland's northern volcanic zone, where we observe that many of the faults with significant vertical displacements still retain fissure-like features, with no vertical displacement, along portions of their lengths. We have created a high resolution digital elevation model (DEM) of the Krafla region using airborne LiDAR and measured the displacement/length profiles of 775 faults, with lengths ranging from 10s to 1000s of metres. We have categorised the faults based on the proportion of the profile that was still fissure-like. Fully-developed faults (no fissure-like regions) were further grouped into those with profiles that had a flat-top geometry (i.e. significant proportion of fault length with constant throw), those with a bell-shaped throw profile and those that show regions of fault linkage. We suggest that a fault can most easily accommodate stress by displacing regions that are still fissure-like, and that a fault would be more likely to accommodate stress by linkage once it has reached the maximum displacement for its fault length. Our results demonstrate that there is a pattern of growth from fissure to fault in the Dmax/L ratio of the categorised faults and propose a model for this growth. These data better constrain our understanding of how fissures develop into faults but also provide insights into the discrepancy in D/L profiles from a typical bell-shaped distribution.

  19. Fissural volcanism, polygenetic volcanic fields, and crustal thickness in the Payen Volcanic Complex on the central Andes foreland (Mendoza, Argentina)

    NASA Astrophysics Data System (ADS)

    Mazzarini, F.; Fornaciai, A.; Bistacchi, A.; Pasquarè, F. A.

    2008-09-01

    Shield volcanoes, caldera-bearing stratovolcanoes, and monogenetic cones compose the large fissural Payen Volcanic Complex, located in the Andes foreland between latitude 35°S and 38°S. The late Pliocene-Pleistocene and recent volcanic activity along E-W trending eruptive fissures produced basaltic lavas showing a within-plate geochemical signature. The spatial distribution of fractures and monogenetic vents is characterized by self-similar clustering with well defined power law distributions. Vents have average spacing of 1.27 km and fractal exponent D = 1.33 defined in the range 0.7-49.3 km. The fractal exponent of fractures is 1.62 in the range 1.5-48.1 km. The upper cutoffs of fractures and vent fractal distributions (about 48-49 km) scale to the crustal thickness in the area, as derived from geophysical data. This analysis determines fractured media (crust) thickness associated with basaltic retroarc eruptions. We propose that the Payen Volcanic Complex was and is still active under an E-W crustal shortening regime.

  20. Anatomy and approaches along the cerebellar-brainstem fissures.

    PubMed

    Matsushima, Ken; Yagmurlu, Kaan; Kohno, Michihiro; Rhoton, Albert L

    2016-01-01

    OBJECT Fissure dissection is routinely used in the supratentorial region to access deeply situated pathology while minimizing division of neural tissue. Use of fissure dissection is also practical in the posterior fossa. In this study, the microsurgical anatomy of the 3 cerebellar-brainstem fissures (cerebellomesencephalic, cerebellopontine, and cerebellomedullary) and the various procedures exposing these fissures in brainstem surgery were examined. METHODS Seven cadaveric heads were examined with a microsurgical technique and 3 with fiber dissection to clarify the anatomy of the cerebellar-brainstem and adjacent cerebellar fissures, in which the major vessels and neural structures are located. Several approaches directed along the cerebellar surfaces and fissures, including the supracerebellar infratentorial, occipital transtentorial, retrosigmoid, and midline suboccipital approaches, were examined. The 3 heads examined using fiber dissection defined the anatomy of the cerebellar peduncles coursing in the depths of these fissures. RESULTS Dissections directed along the cerebellar-brainstem and cerebellar fissures provided access to the posterior and posterolateral midbrain and upper pons, lateral pons, floor and lateral wall of the fourth ventricle, and dorsal and lateral medulla. CONCLUSIONS Opening the cerebellar-brainstem and adjacent cerebellar fissures provided access to the brainstem surface hidden by the cerebellum, while minimizing division of neural tissue. Most of the major cerebellar arteries, veins, and vital neural structures are located in or near these fissures and can be accessed through them. PMID:26274986

  1. Visualization of three dimensional earth fissures in geological structure

    NASA Astrophysics Data System (ADS)

    Zhu, L.; Yu, J.; Liu, Y.; Gong, H.; Chen, Y.; Chen, B.

    2015-11-01

    This paper proposes a new method for visualizing the earth fissures of geological structure in three dimensional (3-D) domains on the basis of the seismic data and features information of earth fissures. The seismic data were interpreted for obtaining the stratagraphic data with various lithological information and the depth of the earth fissures. The spatial distribution of the ground fissures including the dip, strike and width were digitalized on an ArcGIS platform. Firstly, the 3-D geological structure was rebuilt using the Generalized Tri-Prism (GTP) method which is a real solid method for displaying geological structures. The GTP method can reflect the inner material of the strata and can simulate complicated geological structures such as faults and stratagraphic pinch outs. The upper and lower surfaces of each stratum consist of Triangle Irregular Networks (TIN). The inner solid between the two surfaces are a series of triangular prisms. Secondly, since the width of the ground fissure gradually decreases with depth, multiple edge lines of the earth fissures on the bottom stratum surface are deduced on the basis of the fissure characteristics. Then, the model of the earth fissures consisting of a series of triangular pyramids can be constructed using these points and the edge lines. A cutting operation was carried out on the 3-D geological structure using this ground fissures model. If the surfaces of the ground fissures model intersects with the GTPs in the geological structure model, new GTPs were generated within the local regions. During this process, the topological relations between TIN, triangular prism and lines were reconstructed so that the visualization of ground fissures in the geological structure model is realized. This method can facilitate the mechanism for studying fissures and avoid the gaps between the fissure solid and the geological structure to accurately reflect their 3-D characteristics.

  2. Subsurface Gas Flow and Ice Grain Acceleration within Enceladus and Europa Fissures: 2D DSMC Models

    NASA Astrophysics Data System (ADS)

    Tucker, O. J.; Combi, M. R.; Tenishev, V.

    2014-12-01

    The ejection of material from geysers is a ubiquitous occurrence on outer solar system bodies. Water vapor plumes have been observed emanating from the southern hemispheres of Enceladus and Europa (Hansen et al. 2011, Roth et al. 2014), and N2plumes carrying ice and ark particles on Triton (Soderblom et al. 2009). The gas and ice grain distributions in the Enceladus plume depend on the subsurface gas properties and the geometry of the fissures e.g., (Schmidt et al. 2008, Ingersoll et al. 2010). Of course the fissures can have complex geometries due to tidal stresses, melting, freezing etc., but directly sampled and inferred gas and grain properties for the plume (source rate, bulk velocity, terminal grain velocity) can be used to provide a basis to constrain characteristic dimensions of vent width and depth. We used a 2-dimensional Direct Simulation Monte Carlo (DSMC) technique to model venting from both axi-symmetric canyons with widths ~2 km and narrow jets with widths ~15-40 m. For all of our vent geometries, considered the water vapor source rates (1027­ - 1028 s-1) and bulk gas velocities (~330 - 670 m/s) obtained at the surface were consistent with inferred values obtained by fits of the data for the plume densities (1026 - 1028 s-1, 250 - 1000 m/s) respectively. However, when using the resulting DSMC gas distribution for the canyon geometries to integrate the trajectories of ice grains we found it insufficient to accelerate submicron ice grains to Enceladus' escape speed. On the other hand, the gas distributions in the jet like vents accelerated grains > 10 μm significantly above Enceladus' escape speed. It has been suggested that micron-sized grains are ejected from the vents with speeds comparable to the Enceladus escape speed. Here we report on these results including comparisons to results obtained from 1D models as well as discuss the implications of our plume model results. We also show preliminary results for similar considerations applied to Europa

  3. Time-dependent chamber and vent conditions during explosive caldera-forming eruptions

    NASA Astrophysics Data System (ADS)

    Folch, A.; Martí, J.

    2009-04-01

    We use a modified version of the CPIUC model [Macedonio, G., Neri, A., Martí, J., Folch, A., 2005. Temporal evolution of flow conditions in sustained explosive eruptions, Journal of Volcanology and Geothermal Research, 143, 153-172] to simulate chamber and vent conditions during the different phases of a piston-like caldera-forming eruption. Our idealized caldera-forming scenario assumes an initial central-vent conduit that, after critical chamber decompression, migrates to a fissure-vent peripheral conduit(s). Further decompression leads to final piston-like subsidence which stops only after the virtual destruction of the magmatic reservoir. The simulations find that the pressure at the conduit entrance drops during the decompression phases at a rate depending on the conduit geometry, chamber volatile zonation and fragmentation threshold. The higher the volume contrast between the initial central-vent and the final peripheral fissure-vent conduits, the higher the pressure drop and the jump in the mass eruption rate. Pressure increases back to lithostatic during piston subsidence while some compressible magma remains within the chamber. Finally, during the later phase, pressure experiments a gentle increase or decrease depending on the balance between deposition of intra-caldera material and decrease in the contents of volatiles as deeper chamber levels are tapped.

  4. Parachute having improved vent line stacking

    NASA Technical Reports Server (NTRS)

    Hengel, John E.

    1994-01-01

    A parachute having an improved vent line stacking wherein the parachute is provided with a canopy having a central vent opening and a vent band secured to the canopy around the periphery of the vent opening, with a plurality of vent lines each lying on a diameter of the vent opening and having its ends secured to the vent band on opposite sides of the vent opening is described. The vent lines are sewed to the vent band in an order such that the end of a first vent line is sewed to the vent band at a starting point with the end of a second vent band then being sewed to the vent band adjacent to and counterclockwise from the first band. A third vent band is sewed to the vent band adjacent to and clockwise from the first band, with a fourth vent band being sewed to the vent band adjacent to and counterclockwise from the second vent band. It can be seen that, if the vent lines are numbered in the order of being sewed to the vent band, the odd numbered vent lines will run consecutively in a clockwise direction and the even numbered lines will run consecutively in a counterclockwise direction from the starting point. With this order of assembly, each and every vent line will be separated from adjacent vent lines by no more than one vent line in the center of the vent opening where the vent lines cross.

  5. First hydrothermal active vent discovered on the Galapagos Microplate

    NASA Astrophysics Data System (ADS)

    Tao, C.; Li, H.; Wu, G.; Su, X.; Zhang, G.; Chinese DY115-21 Leg 3 Scientific Party

    2011-12-01

    The Galapagos Microplate (GM) lies on the western Gaplapagos Spreading Center (GSC), representing one of the classic Ridge-Ridge-Ridge (R-R-R) plate boundaries of the Nazca, Cocos, and Pacific plates. The presence of the 'black smoke' and hydrothermal vent community were firstly confirmed on the GSC. Lots of hydrothermal fields were discovered on the center and eastern GSC, while the western GSC has not been well investigated. During 17th Oct. to 9th Nov. 2009, the 3rd leg of Chinese DY115-21 cruise with R/V Dayangyihao has been launched along 2°N-5°S near equatorial East Pacific Rise (EPR). Two new hydrothermal fields were confirmed. One is named 'Precious Stone Mountain', which is the first hydrothermal field on the GM. The other is found at 101.47°W, 0.84°S EPR. The 'Precious Stone Mountain' hydrothermal field (at 101.49°W, 1.22°N) is located at an off-axial seamount on the southern GM boundary, with a depth from 1,450 to 1,700m. Hydrothermal fluids emitting from the fissures and hydrothermal fauna were captured by deep-tow video. Few mineral clasts of pyrite and chalcopyrite were separated from one sediment sample, but no sulfide chimney was found yet. Hydrothermal fauna such as alive mussels, crabs, shrimps, tubeworms, giant clams, as well as rock samples were collected by TV-Grab. The study of the seafloor classification with Simrad EM120 multi-beam echosounder has been conducted on the 'Precious Stone Mountain' hydrothermal field. The result indicates that seafloor materials around the hydrothermal field can be characterized into three types, such as the fresh lava, hydrothermal sediment, and altered rock.

  6. [Fissures in biliary calculi. Personal contribution (author's transl)].

    PubMed

    Nano, M; Potenzoni, F; Camandona, M; Casalegno, P A

    1979-04-01

    In a series of 70 patients suffering from biliary lithiasis, the roentgenologic findings of fissures in the calculi was observed in 5 cases examined by means of cholecystography and in 7 cases who underwent cholangiocholecystography. Fissures were demonstrated 11 times in calculi after surgery. The "Mercedes-Benz" sign was never observed at the abdominal examination without contrast medium. The presence of fissures may be an additional sign in the radiologic diagnosis of biliary calculi, but its value is not determinant. PMID:550199

  7. [Sylvius (1614-1672) and his fissure].

    PubMed

    van Gijn, Jan; Gijselhart, Joost P

    2010-01-01

    Franciscus dele Boë, or Sylvius, was born into a family of French Huguenots who had moved to the province of Hessen. He studied medicine in Sedan, Leiden and Basle. He was a private teacher in anatomy in Leiden for some years, and while teaching he drew the attention of his students to the long fissure on either side of the cerebral surface. He practised successfully as a physician in Amsterdam from 1641 onwards, until he was recalled to the chair of medicine in Leiden in 1658. He emphasized the role of chemical processes in the human body (iatrochemistry). PMID:20699035

  8. Corrections of surface fissure effect on apparent resistivity measurements

    NASA Astrophysics Data System (ADS)

    Gance, J.; Sailhac, P.; Malet, J.-P.

    2015-02-01

    Electrical resistivity tomography (ERT) is a useful tool to detect and track water flow paths in the subsoil. However, measurements are strongly affected by subsurface heterogeneities such as fissures of different sizes and genesis (shrinking-swelling, macropores and deformation). In this work, we focus on surface fissures characterized by dimensions lower than the interelectrode spacing and correct their effect on apparent resistivity pseudo-sections by incorporating fissure geometry in the topography. We show that fissures with depths greater than 0.10 times the interelectrode spacing for a dipole-dipole array and equal to 0.16 for the gradient array and the Wenner-Schlumberger arrays create significant anomalies (greater than 5 per cent) in the pseudo-section. Surface fissure widths and dip angles have little effect with respect to the fissure depths which can increase the apparent resistivity up to 200 per cent. The clogging of the fissures with water or soil material decreases the anomaly effect linearly with the percentage of filling. The correction of apparent resistivity values is possible for relatively simple fissure geometries and only requires a manual survey of the surface fissures. It allows to improve the quality of the inverted resistivity section by mitigating the inversion artefacts and therefore a better interpretation.

  9. Organogenesis of mild ocular coloboma in FLS mice: failure of basement membrane disintegration at optic fissure margins.

    PubMed

    Tsuji, Naho; Kita, Katsutoshi; Ozaki, Kiyokazu; Narama, Isao; Matsuura, Tetsuro

    2012-01-01

    Fatty Liver Shionogi (FLS) mice have been shown to develop a hereditary disorder characterized by localized retinochoroidal defects of the ventral fundus very similar to human typical ocular coloboma without microphthalmia. The objective of this study was to determine when and how the failure of the optic fissure closure occurs, and to clarify the disturbed mechanism of basement membrane disintegration during embryonal stage in FLS mice. Fetuses at day 11.5-15.5 of gestation were obtained from dams of FLS and BALB/c strain of mice. Coronal serial sections through the eye were examined by light and electron microscopy. The sections were followed by observation of the basement membrane using reaction with periodic acid-Schiff (PAS) reagent and immunohistochemical staining with anti-Laminin and anti-Type IV collagen antibodies. Both optic fissure margins closely approached each other up to GD 11.5 in all FLS and BALB/c embryos. The inner and outer layers of the optic cup did not normally fuse at midlenticular levels of the optic fissure in almost 70% of FLS fetuses by GD 15.5, whereas both margins were completely fused in all BALB/c fetuses of the same gestational day. In the FLS fetuses at GD 12.5, rolling on one side of fissure margins and consequent asymmetry were observed at the ventral optic fissure. The basement membrane persisted after the close contact of both sides of the fissure margins during GD 11.5 and 15.5. Ultrastructurally, the basal lamina was not disintegrated and mesenchymal cells intervened between the two neuroepithelial layers, resulting in complete separation of both fissure margins at GD 13.0. It is highly probable that the disturbed basement membrane disintegration right before optic fissure closure causes mild ocular coloboma without microphthalmia in FLS mice. PMID:22182670

  10. Coil spring venting arrangement

    DOEpatents

    McCugh, R.M.

    1975-10-21

    A simple venting device for trapped gas pockets in hydraulic systems is inserted through a small access passages, operated remotely, and removed completely. The device comprises a small diameter, closely wound coil spring which is pushed through a guide temporarily inserted in the access passage. The guide has a central passageway which directs the coil spring radially upward into the pocket, so that, with the guide properly positioned for depth and properly oriented, the coil spring can be pushed up into the top of the pocket to vent it. By positioning a seal around the free end of the guide, the spring and guide are removed and the passage is sealed.

  11. Distributed Computing for Seismic Data Retrieval using FISSURES DHI Client FMI Implimented from MatSeis 1.9

    NASA Astrophysics Data System (ADS)

    Hart, D. M.; Li, Q.; Creager, K. C.; Ning, R.; Crotwell, H. P.; Zuzlewski, S.; Hellman, S. B.; Schoch, K. S.; Laughbon, C. J.; Stromme, S. R.

    2004-12-01

    Three software development efforts have recently combined to allow a seamless method for obtaining data from the IRIS DMC over the Internet and analyzing it in MATLAB. During the past few years IRIS has constructed the initial framework and definitions for FISSURES servers and Data Handling Interface (DHI) clients. FISSURES uses the distributed computing language Common Object Request Broker Architecture (CORBA), which allows software systems to work across the Internet in a platform independent and computer-language neutral manner. Starting from the FISSURES object model three seismic services have been defined: event, network and seismogram. From these three object types a DHI client is used to access information through FISSURES services. Using the University of Washington developed FISSURES-Matlab-Interface (FMI) DHI client, all three FISSURES objects can be accessed via the Internet and downloaded into local MATLAB objects, allowing access to earthquake event catalogs, seismograms, network and instrument information. The DHI client FMI can be implemented from MatSeis. MatSeis, developed at Sandia National Laboratory, is a MATLAB based, Graphical User Interface (GUI) controlled software package with seismic data visualization, signal processing, and database importing and exporting capabilities, to list just a few. In this poster, we will discuss the seismic data retrieval currently prototyped for the IRIS DMC, as well as the planned connections to the Northern California Earthquake Data Center (NCEDC), Southern California Earthquake Data Center (SCEDC), and South Carolina Earth Physics Project (SCEPP) data center.

  12. Integral valve provides automatic relief and remote venting

    NASA Technical Reports Server (NTRS)

    Gilmore, R. F.

    1969-01-01

    In-line, pilot-operated, differential area, poppet type valve provides both automatic relief of a tank at a precise over-pressure and remote control of tank venting. Relief and vent operations are separate functions incorporated in an integral valve package.

  13. Overview of the 2012-13 basaltic fissure eruption of Tolbachik, Kamchatka, Russia

    NASA Astrophysics Data System (ADS)

    Belousov, Alexander; Belousova, Marina; Edwards, Benjamin; Volynetz, Anna; Melnikov, Dmitry; Senyukov, Sergey

    2014-05-01

    On 27 November 2012 a short-lived swarm of shallow (<10 km) earthquakes marked the onset of a new eruption from the Tolbachik volcanic complex, in east-central Kamchatka, Russia. The 3.5-km-long radial eruptive fissure opened on the south flank between 1500-2000 m a.s.l. Lava fountaining from multiple small vents ceased after several days and the eruption continued from vents at the southern end of the fissure. Almost continuous lava fountains up to 200 m high issued from a small lava lake located inside the broad, open crater of the largest cinder cone. While explosive activity was rather mild, initial discharge of lava was very high (up to 400 m3/s) and by the end of December 'a'a lava flows had travelled up to 17 km from the vent. SiO2 concentrations for the plagioclase-phyric lava were 54 wt.%, but then decreased to 52 wt.%. In January 2013 lava was transported through a system of lava tubes 1 km long and up to 5 m wide. From tube exit points it propagated in the form of channelized lava streams (velocities 1-3 m/s; discharge rates 30-50 m3/s); on lower slopes of the volcano it propagated mostly as 'a'a flows. Lava channels were frequently dammed by floating clinker and accretionary lava balls, which caused flooding of proximal areas by ropy/shelly/slabby pahoehoe lavas. Locally small volumes of lava were extruded through the upper surfaces and lateral levees of 'a'a lava to form very slowly inflating entrail pahoehoe lava lobes. Starting in mid-February the average intensity of the eruption gradually declined, with sporadic bursts in February and April. By May discharge rates of lava had decreased to approximately 15 m3/s and most of lava started to flow as entrail pahoehoe. By the beginning of June the volume of erupted products (dominantly lavas) reached 0.52km3. The effusion of lava continued until the end of August, when the lava lake in the crater of the active cinder cone became inactive. Weak strombolian outbursts from 1-3 small vents on the bottom of

  14. Vent Relief Valve Test

    NASA Technical Reports Server (NTRS)

    2008-01-01

    Shown is the disassembly, examination, refurbishment and testing of the LH2 ( liquid hydrogen) and LOX (liquid oxygen) vent and relief valves for the S-IVB-211 engine stage in support of the Constellation/Ares project. This image is extracted from high definition video and is the highest resolution available.

  15. Reconstructing recent basaltic fissure eruptions in the Afar Depression, Ethiopia, using satellite imagery

    NASA Astrophysics Data System (ADS)

    Barnie, T. D.; Ferguson, D. J.; Oppenheimer, C.

    2009-12-01

    Since 2005, there have been numerous dike intrusions in the Manda-Hararo rift segment in central Afar, Ethiopia, as part of an on-going rifting event similar to that which occurred at Krafla, Iceland between 1975 and 1984. Two of the dikes have been associated with basaltic fissure eruptions, in August 2007 and in June 2009. A large fissure eruption also occurred in the Erta ‘Ale volcanic range in northern Afar in November 2008, which may be related to the activity further south. These eruptions took place in remote areas and lasted only a few days, making field observation almost impossible. We must therefore rely on the geomorphology and geochemistry of the erupted deposits, and syn-eruption satellite observations of thermally emitted radiance and gas emissions to reconstruct the evolution of these eruptions. Reconstruction of the eruptions is important for i) understanding the relationship between dike intrusion and fissure eruption dynamics ii) understanding the relationship between eruption dynamics and the resulting deposits, iii) interpreting the deposits of pre-historic eruptions from previous rifting events, and iv) estimating the hazard posed to the local population by further activity. In this study we use pre- and post-eruption high resolution ASTER and ALI images to map the morphology of the erupted material, and SEVIRI and MODIS time series of the eruptions to track evolution of the vent dynamics and lava flows. These datasets are augmented by oblique aerial and ground based photographic and FLIR surveys of the cooling lava flows and tephra. ASTER and ALI images are also used to map older erupted materials, which allow us to compare this rifting event with previous events to anticipate future activity.

  16. Remote sensing and petrological observations on the 2012-2013 fissure eruption at Tolbachik volcano, Kamchatka: Implications for reconstruction of the eruption chronology

    NASA Astrophysics Data System (ADS)

    Melnikov, Dmitry; Volynets, Anna O.

    2015-12-01

    We present a reconstruction of the chronological sequence of events that took place during the first days of the 2012-2013 Tolbachik fissure eruption using petrological data and remote sensing methods. We were forced to use this approach because bad weather conditions did not allow direct observations during the first two days of the eruption. We interpreted infrared images from the scanning radiometer VIIRS Suomi NPP and correlated the output with the results of the geochemical study, including comparison of the ash, deposited at the period from 27 to 29 November, with the samples of lava and bombs erupted from the Menyailov and Naboko vents. We argue that the compositional change observed in the eruption products (the decrease of SiO2 concentration and K2O/MgO ratio, increase of MgO concentration and Mg#) started approximately 24 h after the eruption began. At this time the center of activity moved to the southern part of the fissure, where the Naboko group of vents was formed; therefore, this timeframe also characterizes the timing of the Naboko vent opening. The Naboko group of vents remained active until the end of eruption in September 2013.

  17. Monitoring an eruption fissure in 3D: video recording, particle image velocimetry and dynamics

    NASA Astrophysics Data System (ADS)

    Witt, Tanja; Walter, Thomas R.

    2015-04-01

    The processes during an eruption are very complex. To get a better understanding several parameters are measured. One of the measured parameters is the velocity of particles and patterns, as ash and emitted magma, and of the volcano itself. The resulting velocity field provides insights into the dynamics of a vent. Here we test our algorithm for 3 dimensional velocity fields on videos of the second fissure eruption of Bárdarbunga 2014. There we acquired videos from lava fountains of the main fissure with 2 high speed cameras with small angles between the cameras. Additionally we test the algorithm on videos from the geyser Strokkur, where we had 3 cameras and larger angles between the cameras. The velocity is calculated by a correlation in the Fourier space of contiguous images. Considering that we only have the velocity field of the surface smaller angles result in a better resolution of the existing velocity field in the near field. For general movements also larger angles can be useful, e.g. to get the direction, height and velocity of eruption clouds. In summary, it can be stated that 3D velocimetry can be used for several application and with different setup due to the application.

  18. On Small Disturbance Ascent Vent Behavior

    NASA Technical Reports Server (NTRS)

    Woronowicz, Michael

    2015-01-01

    As a spacecraft undergoes ascent in a launch vehicle, its ambient pressure environment transitions from one atmosphere to high vacuum in a matter of a few minutes. Venting of internal cavities is necessary to prevent the buildup of pressure differentials across cavity walls. These pressure differentials are often restricted to low levels to prevent violation of container integrity. Such vents usually consist of fixed orifices, ducts, or combinations of both. Duct conductance behavior is fundamentally different from that for orifices in pressure driven flows governing the launch vehicle ascent depressurization environment. Duct conductance is governed by the average pressure across its length, while orifice conductance is dictated by a pressure ratio. Hence, one cannot define a valid equivalent orifice for a given duct across a range of pressure levels. This presentation discusses development of expressions for these two types of vent elements in the limit of small pressure differentials, explores conditions for their validity, and compares their features regarding ascent depressurization performance.

  19. Fine Mapping and Introgressing a Fissure Resistance Locus

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Rice (Oryza sativa L.) kernel fissuring is a major concern of both rice producers and millers. Fissures are small cracks in rice kernels that increase breakage among kernels when transported or milled, which decrease the value of processed rice. This study employed molecular gene tagging methods to ...

  20. Instrumentation and measurement of airflow and temperature in attics fitted with ridge and soffit vents

    SciTech Connect

    Romero, M.I.; Brenner, R.J.

    1998-12-31

    This study established a research facility where airflow velocities, temperature, and differential pressures could be measured at the ridge of an attic. Following the construction of a test building, sensors were constructed, calibrated, and installed inside the attic. Paired tests were performed for three different ridge vent treatments; two were rolled type vents and one was a baffled vent. When both attics were fitted with the same ridge vent, the airspeed and differential pressure profiles at the ridge were very similar for both attics, indicating that any observed differences in airspeed and differential pressure were caused by the ridge vent treatment used. The baffled vent and rolled vents were then installed on the ridge of the west and east attics, respectively. The data demonstrated that the baffled ridge vent provided a minimum of twice the ridge airspeed of the rolled vents, when all wind conditions were considered. On the day selected to study the direction of the airflows at the ridge, the baffled vent had airflow speeds at the ridge similar to the rolled vent without fabric backing. The baffled vent allowed air to come out of the attic through both sides of the ridge (negative differential pressures on both sides), while the rolled vent without fabric backing caused air to enter through the south side of the ridge and exit through the north side (positive differential pressure on the south side and negative differential pressure on the north), in effect short-circuiting the vent. The fabric-backed rolled vent allowed attic air to come out of the attic through both sides of the ridge, as did the baffled vent, but the airspeed was slower. The baffled vent was the one with the highest airspeed at the ridge and also had both sides of the vent under negative differential pressure, providing the most effective ventilation.

  1. Numerical simulation of earth fissures due to groundwater withdrawal

    NASA Astrophysics Data System (ADS)

    Wang, Z.; Zhang, Y.; Wu, J.; Yu, J.; Gong, X.

    2015-11-01

    Excessive groundwater withdrawal can cause land subsidence and earth fissures. The initiation and propagation of earth fissures are related to tensile failure and crack propagation in soils. Based on fracture mechanics, the crack band model (CBM), one of the smear crack models which is relatively easy to construct and convenient to be integrated into standard finite element codes is used in this paper. The calculated results of CBM are less dependent on the sizes of finite elements. The model was applied to simulate the formation and propagation of earth fissures in the hydrostratigraphic units with a bedrock ridge. The simulated positions and patterns of earth fissures coincide with field observations, suggesting that the modeling approach is adept to simulate the initiation and propagation of earth fissures due to groundwater withdrawal.

  2. Pearl in interhemispheric fissure: A rare phenomenon.

    PubMed

    Agarwal, Vivek; Vijayan, Abhishek; Velho, Vernon; Mally, Rahul

    2012-10-01

    Epidermoid cysts (Keratin pearls) are benign congenital lesions, found commonly in cerebello-pontine angle, suprasellar cistern, sylvian cistern, pineal region, but they are very rare in interhemispheric fissure. Approaching these lesions are challenging to neurosurgeons because of narrow and deep fissure with surrounding vital structures. The present study constitutes an analysis of interhemispheric epidermoid managed at our hospital in last 10 years (Jan 2001-Dec 2010). Total 187 cases of intracranial epidermoid operated in our institute; eight of them were interhemispheric epidermoid making about 4.27% of all epidermoids. The patients were presented with seizures (50%), headache (37%), and weakness (25%). On examination, the common findings were decreased Mini mental score (MMSE) in 50%, motor deficit in 25%, and decreased visual acuity in 25% of cases. All patients underwent craniotomy across the midline as per the location of the lesions. In seven patients, tumors were resected by interhemispheric approach but in one by transcortical. Lesion were excised with microscope and endoscopic assistance with measures to prevent spillage of epidermoid tissue while excision. Post excision tumor bed was irrigated with hydrocortisone diluted saline. All patients except one improved after surgery and non-developed chemical meningitis. One patient of parietal interhemispheric epidermoid with transcortical approach developed weakness in immediate post-operative period. Patients were followed for average 6.8 year without any recurrence. Interhemispheric epidermoids are rare tumors. Achieving safe complete excision without spillage is surgical goal to prevent chemical meningitis and recurrence. Endoscope assists in achieving complete excision so decrease incidence of chemical meningitis and recurrence. PMID:23559996

  3. Methods for monitoring land subsidence and earth fissures in the Western USA

    NASA Astrophysics Data System (ADS)

    Fergason, K. C.; Rucker, M. L.; Panda, B. B.

    2015-11-01

    Depletion of groundwater resources in many deep alluvial basin aquifers in the Western USA is causing land subsidence, as it does in many regions worldwide. Land subsidence can severely and adversely impact infrastructure by changing the ground elevation, ground slope (grade) and through the development of ground cracks known as earth fissures that can erode into large gullies. Earth fissures have the potential to compromise the foundations of dams, levees, and other infrastructure and cause failure. Subsequent to an evaluation of the overall subsidence experienced in the vicinity of subsidence-impacted infrastructure, a detailed investigation to search for earth fissures, and design and/or mitigation of potentially effected infrastructure, a focused monitoring system should be designed and implemented. Its purpose is to provide data, and ultimately knowledge, to reduce the potential adverse impacts of land subsidence and earth fissure development to the pertinent infrastructure. This risk reduction is realized by quantifying the rate and distribution of ground deformation, and to detect ground rupture if it occurs, in the vicinity of the infrastructure. The authors have successfully designed and implemented monitoring systems capable of quantifying rates and distributions of ground subsidence and detection of ground rupture at multiple locations throughout the Western USA for several types of infrastructure including dams, levees, channels, basins, roadways, and mining facilities. Effective subsidence and earth fissure monitoring requires understanding and quantification of historic subsidence, estimation of potential future subsidence, delineation of the risk for earth fissures that could impact infrastructure, and motivation and resources to continue monitoring through time. A successful monitoring system provides the means to measure ground deformation, grade changes, displacement, and anticipate and assess the potential for earth fissuring. Employing multiple

  4. D0 Vent Stacks

    SciTech Connect

    Fuerst, J.D.; /Fermilab

    1988-01-22

    There are two nitrogen/argon exhaust headers in the D0 cryogenic piping system, one for the liquid argon dewar and another for the three argon calorimeters. These headers serve two functions, venting both nitrogen exhaust from the cooling loops and cold argon gas should any argon vessel blow a relief. These headers are vacuum jacketed until they exit the building. At that point, uninsulated exhaust stacks direct the flow into the atmosphere. This note deals with the these stacks.

  5. Spacecraft Compartment Venting

    NASA Technical Reports Server (NTRS)

    Scialdone, John J.

    1998-01-01

    At various time concerns have been expressed that rapid decompressions of compartments of gas pockets and thermal blankets during spacecraft launches may have caused pressure differentials across their walls sufficient to cause minor structural failures, separations of adhesively-joined parts, ballooning, and flapping of blankets. This paper presents a close form equation expressing the expected pressure differentials across the walls of a compartment as a function of the external to the volume pressure drops, the pressure at which the rates occur and the vent capability of the compartment. The pressure profiles measured inside the shrouds of several spacecraft propelled by several vehicles and some profiles obtained from ground vacuum systems have been included. The equation can be used to design the appropriate vent, which will preclude excessive pressure differentials. Precautions and needed approaches for the evaluations of the expected pressures have been indicated. Methods to make a rapid assessment of the response of the compartment to rapid external pressure drops have been discussed. These are based on the evaluation of the compartment vent flow conductance, the volume and the length of time during which the rapid pressure drop occurs.

  6. Staged venting of fuel cell system during rapid shutdown

    DOEpatents

    Keskula, Donald H.; Doan, Tien M.; Clingerman, Bruce J.

    2004-09-14

    A venting methodology and system for rapid shutdown of a fuel cell apparatus of the type used in a vehicle propulsion system. H.sub.2 and air flows to the fuel cell stack are slowly bypassed to the combustor upon receipt of a rapid shutdown command. The bypass occurs over a period of time (for example one to five seconds) using conveniently-sized bypass valves. Upon receipt of the rapid shutdown command, the anode inlet of the fuel cell stack is instantaneously vented to a remote vent to remove all H.sub.2 from the stack. Airflow to the cathode inlet of the fuel cell stack gradually diminishes over the bypass period, and when the airflow bypass is complete the cathode inlet is also instantaneously vented to a remote vent to eliminate pressure differentials across the stack.

  7. Staged venting of fuel cell system during rapid shutdown

    DOEpatents

    Clingerman, Bruce J.; Doan, Tien M.; Keskula, Donald H.

    2002-01-01

    A venting methodology and system for rapid shutdown of a fuel cell apparatus of the type used in a vehicle propulsion system. H.sub.2 and air flows to the fuel cell stack are slowly bypassed to the combustor upon receipt of a rapid shutdown command. The bypass occurs over a period of time (for example one to five seconds) using conveniently-sized bypass valves. Upon receipt of the rapid shutdown command, the anode inlet of the fuel cell stack is instantaneously vented to a remote vent to remove all H.sub.2 from the stack. Airflow to the cathode inlet of the fuel cell stack gradually diminishes over the bypass period, and when the airflow bypass is complete the cathode inlet is also instantaneously vented to a remote vent to eliminate pressure differentials across the stack.

  8. Airbag vent valve and system

    NASA Technical Reports Server (NTRS)

    Peterson, Leslie D. (Inventor); Zimmermann, Richard E. (Inventor)

    2001-01-01

    An energy absorbing airbag system includes one or more vent valve assemblies for controlling the release of airbag inflation gases to maintain inflation gas pressure within an airbag at a substantially constant pressure during a ride-down of an energy absorbing event. Each vent valve assembly includes a cantilever spring that is flat in an unstressed condition and that has a free end portion. The cantilever spring is secured to an exterior surface of the airbag housing and flexed to cause the second free end portion of the cantilever spring to be pressed, with a preset force, against a vent port or a closure covering the vent port to seal the vent port until inflation gas pressure within the airbag reaches a preselected value determined by the preset force whereupon the free end portion of the cantilever spring is lifted from the vent port by the inflation gases within the airbag to vent the inflation gases from within the airbag. The resilience of the cantilever spring maintains a substantially constant pressure within the airbag during a ride-down portion of an energy absorbing event by causing the cantilever spring to vent gases through the vent port whenever the pressure of the inflation gases reaches the preselected value and by causing the cantilever spring to close the vent port whenever the pressure of the inflation gases falls below the preselected value.

  9. Study of the deformation mechanism of the Gaoliying ground fissure

    NASA Astrophysics Data System (ADS)

    Cheng, G.; Wang, H.; Luo, Y.; Guo, H.

    2015-11-01

    The Gaoliying ground fissure in Beijing has caused building cracking and road damage, and has seriously influenced city construction. Based on investigations and trenching, the influences of the fault and the variation of groundwater levels on the formation mechanism of the Gaoliying ground fissure were investigated by using FLAC3D. The results indicated that (1) the surface location of Gaoliying fissure is controlled by the underlying normal fault activity, and over pumping further exacerbates development of the ground fissure; (2) when the groundwater level declines, obvious differential settlement occurs at both sides of the ground fissure, in which greater settlement occurs in the vicinity of the hanging wall, the greater the distance from the hanging wall, the smaller the ground subsidence, however smaller ground subsidence occurs in the vicinity of the footwall, the greater the distance from the footwall, the greater the ground subsidence; (3) the vertical velocity of the ground fissure triggered by the fault activity and groundwater decline ranges from 15.5 to 18.3 mm a-1, which is basically in line with the monitoring data. The fault activity contributes about 28-39 %, and the groundwater contributes about 61-72 % to the deformation of the ground fissure, respectively.

  10. Visual Observations and Geologic Settings of the Newly-Discovered Black Smoker Vent Sites Across the Galapagos Ridge-Hotspot Intersection

    NASA Astrophysics Data System (ADS)

    Anderson, P.; Haymon, R.; MacDonald, K.; White, S.

    2006-12-01

    Nearly one-fifth of the global mid-ocean ridge is hotspot-affected, yet very little is known about how hotspots affect quantity and distribution of high-temperature hydrothermal vents along the ridge. During the 2005-06 GalAPAGoS expedition, acoustic and plume sensor surveys were conducted across the Galapagos ridge- hotspot intersection, lon. 94.5ºW- lon. 89.5ºW, to map fine scale geologic features and locate hydrothermal plumes emanating from the ridge crest. Where significant plumes were detected, the Medea fiber-optic camera sled was used successfully to find and image high-temperature vents on the seafloor. With Medea we discovered and imaged the first active and recently extinct black smokers known along the entire Galapagos Spreading Center (GSC), and documented the geologic setting of these vents. The Medea survey imaged numerous inactive vents as well as 3 active high-temperature vent fields along the ridge at 94º 04.5'W (Navidad Site), 91º56.2'W (Iguanas Site) and 91º54.3'W (Pinguinos Site). Two recently extinct vent fields also were identified at 91º23.4'-23.7'W and 91º13.8'W. All of the high-temperature vent sites that we identified along the GSC are found above relatively shallow AMC reflectors and are located in the middle 20% of ridge segments. Without exception the vent sites are located along fissures atop constructional axial volcanic ridges (AVR's) composed of relatively young pillow basalts. In some cases, the vents were associated with collapses adjacent to the fissures. The fissures appear to be eruptive sources of the pillow lavas comprising the AVR's. Video images of the chimneys show mature, cylindrical structures, up to 14m high; little diffuse flow; few animals; and some worm casts and dead clam shells, suggesting prior habitation. We conclude that distribution of the vents is controlled by magmatic processes, (i.e., by locations of shallow AMC magma reservoirs and eruptive fissures above dike intrusions), and that there is

  11. Tapped-Hole Vent Path

    NASA Technical Reports Server (NTRS)

    Chandler, J. A.

    1983-01-01

    Long helical vent path cools and releases hot pyrotechnical gas that exits along its spiraling threads. Current design uses 1/4-28 threads with outer diameter of stud reduced by 0.025 in. (0.62 mm). To open or close gassampler bottle, pyrotechnic charges on either one side or other of valve cylinder are actuated. Gases vented slowly over long path are cool enough to present no ignition hazard. Vent used to meter flow in refrigeration, pneumaticcontrol, and fluid-control systems by appropriately adjusting size and length of vent path.

  12. Safe venting of hydrogen

    SciTech Connect

    Stewart, W.F.; Dewart, J.M.; Edeskuty, F.J.

    1990-01-01

    The disposal of hydrogen is often required in the operation of an experimental facility that contains hydrogen. Whether the vented hydrogen can be discharged to the atmosphere safely depends upon a number of factors such as the flow rate and atmospheric conditions. Calculations have been made that predict the distance a combustible mixture can extend from the point of release under some specified atmospheric conditions. Also the quantity of hydrogen in the combustible cloud is estimated. These results can be helpful in deciding of the hydrogen can be released directly to the atmosphere, or if it must be intentionally ignited. 15 refs., 5 figs., 2 tabs.

  13. Tornado protection by venting

    SciTech Connect

    Cavanagh, C.A.

    1987-01-01

    The purpose of this paper is to demonstrate the ability to protect a modern nuclear power plant from the effects of a tornado by the use of a system of venting in all safety-related structures outside of the containment. The paper demonstrates this by presenting a method of analysis and of equipment selection that fully complies with the intent and the letter of applicable federal regulatory guides. A report of an actual tornado in the City of Kalamazoo, Michigan, suggests that the concept of sealing a plant during a tornado may not always be applicable.

  14. Two Vent Fields Discovered at the Ultraslow Spreading Arctic Ridge System

    NASA Astrophysics Data System (ADS)

    Pedersen, R. B.; Thorseth, I. H.; Hellevang, B.; Schultz, A.; Taylor, P.; Knudsen, H. P.; Steinsbu, B. O.

    2005-12-01

    Two high-temperature vent fields were discovered at the Mohns Ridge during an expedition with the Norwegian research vessel "G.O. Sars" in July 2005. Both vent fields are located within the southernmost segment of the Mohns Ridge approximately 50 km north of the West Jan Mayen Fracture Zone. Water depths along this segment range from 3800 meters close to the fracture zone to ~500 meters at the segment centre where the vent fields are located. The largest field - named "Gallionella Garden" - is situated within a rift graben where high- and low-temperature venting occurs along ridge-parallel normal faults and fissures. Presently we have documented high- and low-temperature venting along more then 2 km of the fault and fissure system in the area. The high-temperature venting takes place at around 550 mbsl at the base of a 100 meter high fault wall and was traced ~500 meters along strike. The field consists of at least 10 major vent sites, each composed of multiple chimneys that are up to 5-10 meters tall. There are also large areas of diffuse flow. The temperature of the vent fluids was measured to be above 260°C at a chimney orifice. This is at the boiling point of seawater at these water depths, and gas bubbling was observed at several of the vent sites. A sample of the top of a chimney consists of anhydrite, barite, sphalerite and pyrite. Outside the high-temperature vent area mounds of ferric iron are abundant. Such deposits have presently been traced along ~2 km of the faults and fissure system in the area. The deposits are predominantly made up of branching and twisted stalks comparable to those formed by the iron oxidizing bacteria Gallionella ferruginea showing that the precipitation is mediated by microbial activity. The temperatures below the upper crust of a mound were measured to be one degree above the ambient water temperature. The Fe-oxyhydroxides show Nd-isotope compositions similar to the basaltic crust and Sr-isotope compositions close to that of

  15. Calcified gallstone fissures: the reversed Mercedes Benz sign.

    PubMed

    Strijk, S P

    1987-01-01

    This article describes the occurrence of an unusual radiating pattern of calcification in the center of large radiolucent gallstones. The radiographic findings are attributed to calcium deposition within the fissures of biliary calculi. PMID:3556975

  16. Vented gaseous deflagrations modelling of hinged inertial vent covers.

    PubMed

    Molkov, V V; Grigorash, A V; Eber, R M; Makarov, D V

    2004-12-10

    The model of explosion pressure build up in enclosures with inertial vent covers and the CINDY code implementing the model are validated against experiments by Hochst and Leuckel (1998) in a 50 m3 vessel with a pair of ceiling-mounted upwards-opening hinged doors in a 'butterfly' configuration with surface densities of 73 and 124 kg/m2 under conditions of initially quiescent and turbulent mixtures. The model and the code are further validated against an experiment by Zalosh (1978) in a 33.5 m3 room-like enclosure with a pair of wall-mounted rectangular doors, in a parallel configuration, each hinged at its bottom edge with a surface density of 23.1 kg/m2 and initially quiescent mixture. A formula for the torque acting upon a rotating venting door is derived under conditions of vent cover jet formation. The vent cover jet effect decreases the torque three times compared to an elementary approach valid at the start of vent cover movement. It is demonstrated that, similar to translating vent covers, the vent cover jet effect is crucial for prediction of interdependent vent cover displacement in time and pressure transients. PMID:15561358

  17. 24 CFR 3280.611 - Vents and venting.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 24 Housing and Urban Development 5 2010-04-01 2010-04-01 false Vents and venting. 3280.611 Section 3280.611 Housing and Urban Development Regulations Relating to Housing and Urban Development (Continued) OFFICE OF ASSISTANT SECRETARY FOR HOUSING-FEDERAL HOUSING COMMISSIONER, DEPARTMENT OF HOUSING AND URBAN DEVELOPMENT MANUFACTURED...

  18. Differential compaction mechanism for earth fissures near Casa Grande, Arizona.

    USGS Publications Warehouse

    Jachens, R.C.; Holzer, T.L.

    1982-01-01

    Precise gravity measurements indicate that earth fissures or tension cracks caused by ground-water withdrawal within a 10km2 area SE of Casa Grande are associated with relief on the buried interface between the alluvial aquifer and underlying bedrock. These relations suggest that the fissures are forming in response to localized differential compaction caused by localized variations of aquifer-system thickness. -from Authors

  19. Implications of ground-deformation measurements across earth fissures in subsidence areas in the southwestern USA

    USGS Publications Warehouse

    Holzer, Thomas L.

    2010-01-01

    Ground deformation was monitored at earth fissures in areas of land subsidence induced by groundwater extraction in the southwestern United States. The ground deformation is consistent with the mechanism that fissures are caused by horizontal strains generated by bending of overburden in response to localized differential compaction. Subsidence profiles indicated that localized differential subsidence occurred across the fissures and that maximum convex-upward curvature was at the fissure. The overall shape of the profile stayed similar with time, and maximum curvature remained stationary at the fissure. Horizontal displacements were largest near the fissure, and generally were small to negligible away from the fissure. Maximum tensile horizontal strains were at the fissure and coincided with maximum curvature in the subsidence profiles. Horizontal tensile strain continued to accumulate at fissures after they formed with rates of opening ranging from 30 to 120 microstrain/year at fissures in Arizona.

  20. Predominant cultivable microflora of human dental fissure plaque.

    PubMed Central

    Theilade, E; Fejerskov, O; Karring, T; Theilade, J

    1982-01-01

    Plaque developed in 10 occlusal fissures from unerupted third molars during implantation for 200 to 270 days in lower molars of dental students was studied. To characterize the predominant cultivable flora, 592 isolates (51 to 67 from each fissure) were subcultured from anaerobic roll tubes. Twenty-eight of the isolates were lost. Streptococci constituted 8 to 86% (median, 45%) of the isolates, Streptococcus mutans constituted 0 to 86% (median, 25%) and S. sanguis constituted 0 to 15% (median, 1%). A few isolates of "S. mitior" and "S. milleri" were found, but no S. salivarius. Staphylococci made up 0 to 23% (median, 9%). Gram-positive rods constituted 6 to 59% (median, 35%). Of these, 0 to 46% (median, 18%) were Actinomyces naeslundii and A. viscosus, but no anaerobic actinomyces were isolated. Arachnia and propionibacteria made up small proportions, lactobacilli were isolated from two fissures, constituting 10 and 29%, and eubacteria were isolated from one fissure (27%). Gram-negative cocci made up 0 to 46% (media, 4%). Only two isolates of gram-negative rods were found, both facultative anaerobes. Although 8 of the 10 fissures had large proportions of S. mutans, lactobacilli, or both, no caries was found even with microradiography. The large individual variation probably reflects differences in initial colonization from saliva and in growth conditions in each fissure. PMID:7095858

  1. Battery vent valve

    SciTech Connect

    McCartney, C.P. Jr.; Montgomery, C.C.; Meadows, C.A.; Cole, B.A.

    1988-10-25

    This patent describes an electric storage battery comprising (1) a container defining a compartment containing gas-generating electro-chemical means for producing an electric current, and (2) check/relief valve means operatively associated with the container upon closing to isolate the electrochemical means from the ambient atmosphere and upon opening to vent the compartment when the internal pressure of the gas generated in the compartment exceeds a predetermined superatmospheric pressure the improvement wherein the valve comprises: a housing defining a vent chamber and including a valve seat projecting into the chamber, the seat having a sloping exterior sealing surface; an inlet in one end of the housing for admitting gas into the chamber from the compartment; means for exhausting the gas from the chamber to the environment; and a sealing member in the chamber circumscribing the inlet for controlling the internal pressures at which the opening and closing occurs and as necessary, for dumping relatively large volumes of the gas without excessive build-up of the internal pressure in the container. The sealing member comprising an annular elastomeric skirt secured at one end and having a tubular portion extending from the one end above the inlet so as to provide an internal annular surface exposed to the internal gas pressure and a sealing edge on the interior of the other end of the tubular portion circumferentially sealing engaging the sloping exterior sealing surface when the valve is closed

  2. EVALUATION OF SOIL VENTING APPLICATION

    EPA Science Inventory

    The ability of soil venting to inexpensively remove large amounts of volatile organic compounds (VOCs) from contaminated soils is well established. However, the time required using venting to remediate soils to low contaminant levels often required by state and federal regulators...

  3. Pulmonary Fissure Integrity and Collateral Ventilation in COPD Patients

    PubMed Central

    Pu, Jiantao; Wang, Zhimin; Gu, Suicheng; Fuhrman, Carl; Leader, Joseph K.; Meng, Xin; Tedrow, John; Sciurba, Frank C.

    2014-01-01

    Purpose To investigate whether the integrity (completeness) of pulmonary fissures affects pulmonary function in patients with chronic obstructive pulmonary disease (COPD). Materials and Methods A dataset consisting of 573 CT exams acquired on different subjects was collected from a COPD study. According to the global initiative for chronic obstructive lung disease (GOLD) criteria, these subjects (examinations) were classified into five different subgroups, namely non-COPD (222 subjects), GOLD-I (83 subjects), GOLD-II (141 subjects), GOLD-III (63 subjects), and GOLD-IV (64 subjects), in terms of disease severity. An available computer tool was used to aid in an objective and efficient quantification of fissure integrity. The correlations between fissure integrity, and pulmonary functions (e.g., FEV1, and FEV1/FVC) and COPD severity were assessed using Pearson and Spearman's correlation coefficients, respectively. Results For the five sub-groups ranging from non-COPD to GOLD-IV, the average integrities of the right oblique fissure (ROF) were 81.8%, 82.4%, 81.8%, 82.8%, and 80.2%, respectively; the average integrities of the right horizontal fissure (RHF) were 62.6%, 61.8%, 62.1%, 62.2%, and 62.3%, respectively; the average integrities of the left oblique fissure (LOF) were 82.0%, 83.2%, 81.7%, 82.0%, and 78.4%, respectively; and the average integrities of all fissures in the entire lung were 78.0%, 78.6%, 78.1%, 78.5%, and 76.4%, respectively. Their Pearson correlation coefficients with FEV1 and FE1/FVC range from 0.027 to 0.248 with p values larger than 0.05. Their Spearman correlation coefficients with COPD severity except GOLD-IV range from −0.013 to −0.073 with p values larger than 0.08. Conclusion There is no significant difference in fissure integrity for patients with different levels of disease severity, suggesting that the development of COPD does not change the completeness of pulmonary fissures and incomplete fissures alone may not contribute to the

  4. Ice-Confined Basaltic Eruptive Fissure Complexes in Iceland: Accessible Analogs for Understanding Shallow Submarine Ridge Construction

    NASA Astrophysics Data System (ADS)

    Skilling, I. P.; Mercurio, E.; Cameron, B. I.

    2009-12-01

    In southwest Iceland, the onshore Mid-Atlantic Ridge (Reykjanes Ridge) forms a series of fissure and central vent (“shield”) volcanic complexes, known as the Western Volcanic Zone (WVZ). Sveifluháls is one of the longest fissure-fed complexes in the WVZ, and was erupted in an ice-confined environment during the Last Glacial Maximum. There are more than 1000 similar such glaciovolcanic ridges in Iceland, but there are few detailed studies of their construction. The complexes are both an important record of North Atlantic terrestrial ice presence and thicknesses in the Pleistocene, and are accessible analogs for submarine basaltic ridge volcanism in water less than a few hundred metres deep. This study focuses on the volcanic and sedimentary processes, products and depositional environments at Sveifluháls. Sveifluháls is a complex of closely spaced, sub-parallel, and multiple vent ridges. Ridges are constructed of numerous, regularly-spaced to overlapping and steep-sided topographic highs (point-source vents or tuff cones) and short, lower, intervening ridge segments (fissure vents or “tuff ridges”). Both tuff cones and tuff ridges consist dominantly of basal subaqueous lavas draped by phreatomagmatic tephra. Point-source vents have an average spacing of 0.7 km. Up to nine sub-parallel fissures/ridges occur, spaced 0.03-0.5 km apart. Ridges range from a few hundred metres to 21.5km in length. The majority of the phreatomagmatic has been rotated, slumped or slid. An upper sequence of inward and outward-dipping, over-steepened (rotated) “soft-margined” domains and angular blocks of bedded, subaqueously-deposited “Surtseyan” lapilli tuff, overlies more widespread aprons of very similar, but mostly slumped massive tephra. Important results to date include the observation that 1-2m wide dikes, emplaced into formerly wet unconsolidated tephra, form a volumetrically important part of the complex. The host tephra commonly shows evidence of deformation and

  5. Identification of possible recent water/lava source vents in the Cerberus plains: Stratigraphic andcrater count age constraints

    NASA Astrophysics Data System (ADS)

    Thomas, Rebecca J.

    2013-04-01

    In order to investigate sources of lava and water to the Cerberus plains of Mars, geomorphological mapping on High Resolution Imaging Science Experiment (HiRISE) images was carried out to reveal the history of activity of fissures and pits which lie upstream of channels and deposits associated with a wrinkle ridge near Cerberus Fossae. The fissures and pits are superbly exposed and imaged, and flows and channels emanate directly from them, interpreted as clear evidence that these are vents. The mapping establishes stratigraphic relationships between the plains and the channels and deposits originating from the vents, establishing the vent history. For example, to the south of the wrinkle ridge, both incised channels and leveed flows extend onto the southern plain and are clearly the final phase of plains-forming activity. Conversely, to the north, vent-sourced channels only incise the plain close to the ridge—beyond that, they are overlain by large-scale regional flows that appear to have originated from the direction of Athabasca Valles. In the southeast, there is evidence of contemporaneity between vent-sourced activity and large-scale plains-forming flow that was not sourced from the vents, indicating that activity here was part of a broader process of Cerberus plains formation from multiple sources. Crater counts show all the activity to be Late Amazonian, with the latest activity tentatively dating to circa 11 Ma. Thus, this study implies that very recent outflows from these vents contributed to the formation of the Cerberus plains and constrains the timing and local flow direction of plains-forming deposits from other sources.

  6. Arteries and Veins of the Sylvian Fissure and Insula: Microsurgical Anatomy.

    PubMed

    Delion, Matthieu; Mercier, Philippe; Brassier, Gilles

    2016-01-01

    We present a vascular anatomical study of the arteries and veins of the sylvian fissure and insula.A good knowledge of the sylvian fissure, the insula, and their vascular relationship would seem mandatory before performing surgery in this area, whatever the type of surgery (aneurysms, arteriovenous malformations, insular tumors).We start with the sylvian fissure and insula morphology, followed by the MCA description and its perforators, with special attention paid to the insular perforators. We demonstrate that the long insular perforators penetrating in the superior part of the posterior short gyrus and long gyri vascularize, respectively, the corticonuclear and corticospinal fasciculi. We particularly insist too on three anatomical constants regarding the vascularization of the insula, already described in the literature: The superior periinsular sulcus is the only sulcus on the lateral surface of the brain without an artery along its axis; the superior branch of the MCA supplies the anterior insular pole and both the anterior and middle short gyri in 100 % of cases; in at least 90 % of cases, the artery that supplied the central insular sulcus continued on to become the central artery.We end with the anatomical study of the veins and cisterns. PMID:26508410

  7. Resin infiltration of fissure caries with various techniques of pretreatment in vitro.

    PubMed

    Lausch, Julian; Paris, Sebastian; Selje, Timo; Dörfer, Christof E; Meyer-Lueckel, Hendrik

    2015-01-01

    The resin infiltration technique might be used for occlusal caries lesions in order to arrest their progression. This in vitro study evaluated the influence of various modifications of the infiltration technique on the penetration abilities of the infiltrant into occlusal lesions. Extracted human molars and premolars (n = 140) with non-cavitated white spot lesions were randomly allocated to 7 groups. As control, specimens were etched with 15% hydrochloric acid (HCl) gel for 120 s and resin infiltrated for 180 s (Icon; DMG). As modification HCl gel reduced in surface tension and viscosity with and without abrasives was applied using 3 different types of brushes either to oscillate or rub the HCl gel onto the enamel surface. The median maximum lesion depth was 1,232 µm (interquartile range 882-1,513). Compared with the control procedure [23% (16/50)] a higher percentage penetration was observed if the HCl gel was mixed with a small amount of abrasives were rubbed into the fissures using a modified brush with stiff bristles that were adjusted to the fissure relief for either 120 s [100% (64/100)] or 30 s [98% (61/100); p < 0.05; Mann-Whitney test]. All other experimental treatments resulted in penetration results in-between. It can be concluded that the use of an abrasive HCl gel in conjunction with a modified brush mostly enhances resin infiltration into fissure caries lesions. PMID:25427531

  8. Vesicle size analysis of magmatic and phreatomagmatic phases of the 934-40 AD Eldgjá fissure eruption, southern Iceland

    NASA Astrophysics Data System (ADS)

    Thordarson, T.; Moreland, W.; Houghton, B. F.

    2014-12-01

    Eldgjá is a ~75 km volcanic fissure which erupted in the middle of the 10th century. It belongs to the Katla volcanic system and is of the mixed-cone row type. The eruption lasted several years and produced two large lava fields (18.3 km3) and a widespread basaltic tephra deposit (4.5 km3 or 1.3 km3 DRE). Proximal tephra deposits are up to 5 m thick and contain as many as 10 sub-units which vary in thickness parallel to the fissure, indicating multiple points of origin. Many of the lowest units were produced by phreatomagmatic activity and dispersion of these units indicate an origin below the Mýrdalsjökull glacier. Two sections were chosen to represent magmatic and phreatomagmatic activity. A 3.7 m section at Skælingar, 0.5 km south-east of Eldgjá, represents the magmatic products. The phreatomagmatic products are represented by a 2.7 m thick section at Stóragil, located 10-15 km south and east of the vent system. The sampled phreatomagmatic part of the section is 1.12 m thick. These sections were logged and then each sub-unit was sampled for density analysis which involves picking 100 clasts in the 8 to 32 mm size range from horizons less than 5 cm thick. Thin-sections were then made from representative clasts of each sub-unit. Nested images of these thin-sections were analysed for vesicle size and shape. The magmatic clasts have unimodal, normal to moderately log-normal density distributions with a mean density of 7900-7500 kg.m-3 (60-70% vesicularity) and a range of around 8600 kg.m-3 (40% vesicularity). The log-normal distribution of some samples may be explained by the inclusion of previously degassed magma in the eruption. The section at Stóragil contains both phreatomagmatic and magmatic products. The phreatomagmatic samples have characteristic plateau-like distributions with a mean density of 7200-7500 kg.m-3 (70-80% vesicularity) and a range of around 8420 kg.m-3 (45% vesicularity). One layer shows a change from phreatomagmatic to magmatic

  9. Open Fissure Folds record coseismic loading and postseismic stress relaxation

    NASA Astrophysics Data System (ADS)

    Nüchter, Jens-Alexander

    2015-03-01

    Open Fissure Folds hosted by high pressure/low temperature metamorphic rocks of south Evia (Greece) are introduced, their structural and microstructural record is analysed, and a mechanical model is proposed. Open Fissure Folds are preserved as at least two parallel folded quartz-feldspar veins separated by narrow buckled rock columns. The veins originated as tensile cracks that propagated in the middle crust driven by high differential stress. Features diagnostic for Open Fissure Folds indicate that the rock columns represented the layers of high viscosity, and not the veins as consistently reported in many previous studies on folded veins. This record is taken to indicate that buckling of the rock columns initiated after arrest of the fractures and terminated prior to complete vein sealing. Accordingly, mechanical decoupling by open fissures allowed for buckling of the rock columns in response to episodic creep of the host rocks according to stress relaxation, as expected for postseismic deformation in the earthquake cycle. I propose that the parental fractures propagated in response to quasi-instantaneous coseismic loading of the middle crust. Buckling was attributed to transient postseismic creep and stress relaxation. Complete sealing of the veins occurred when stresses were largely relaxed. Each Open Fissure Fold records the stress and strain history of a single earthquake.

  10. 24 CFR 3280.611 - Vents and venting.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ...) Materials—(1) Pipe. Vent piping shall be standard weight steel, wrought iron, brass, copper tube DWV, listed... fixture unit loading. (4) The device shall be installed in a location that permits a free flow of air...

  11. Provisions for containment venting in Germany

    SciTech Connect

    Wilhelm, J.G.

    1997-08-01

    In this short paper an overlook is given of the systems developed in Germany for filtered containment venting and their implementation in nuclear power plants. More information on the development can be found in the Proceedings of the DOE/NRC Aircleaning Conferences. In Germany, 28.8 % of the electric energy is produced by 19 nuclear power reactors. No new power reactor is expected to be built at least within the next ten years, but France and Germany cooperate in the development of a future European Power Reactor (ERP). This reactor type will be fitted with a core catcher and passive cooling in order to avoid serious consequences of a hypothetical core meltdown accident so that provisions for containment venting are not required. 3 refs., 6 figs., 1 tab.

  12. Research on positioning of Xi'an ground fissures with InSAR quality map

    NASA Astrophysics Data System (ADS)

    Xu, Li; Zhao, Chao-ying

    2011-02-01

    Xi'an ground fissure is a typical geo-hazard with nearly half a century history, which have been caused serious damages to roads, building and other civil facilities. Based on the theory of deformation de-correlation of the active ground fissures, this manuscript mainly investigated the positioning method of active ground fissures by analyzing the pseudo-coherence map of adaptively filtered differential interferogram. We took two ERS1 SAR data during 1992-1993 as an example to investigate the active fissures position during this period. Consequently, high consistency between newly detected fissures and the ground fissure map from engineering geological investigation can be achieved.

  13. Cost considerations in the treatment of anal fissures.

    PubMed

    Brisinda, Giuseppe; Bianco, Giuseppe; Silvestrini, Nicola; Maria, Giorgio

    2014-08-01

    Anal fissure is a split in the lining of the distal anal canal. Lateral internal sphincterotomy remains the gold standard for treatment of anal fissure. Although technique is simple and effective, a drawback of this surgical procedure is its potential to cause minor but some times permanent alteration in rectal continence. Conservative approaches (such as topical application of ointment or botulinum toxin injections) have been proposed in order to treat this condition without any risk of permanent injury of the internal anal sphincter. These treatments are effective in a large number of patients. Furthermore, with the ready availability of medical therapies to induce healing of anal fissure, the risk of a first-line surgical approach is difficult to justify. The conservative treatments have a lower cost than surgery. Moreover, evaluation of the actual costs of each therapeutic option is important especially in times of economic crisis and downsizing of health spending. PMID:24867398

  14. Perioperative Identification of an Accessory Fissure of the Right Lung

    PubMed Central

    Taverne, Yannick; Kleinrensink, Gert-Jan; de Rooij, Peter

    2015-01-01

    Anatomical variations of lungs are common in clinical practice; however, they are sometimes overlooked in routine imaging. Surgical anatomy of the lung is complex and many variations are known to occur. A defective pulmonary development gives rise to variations in lobes and fissures. Morphological presentation is of clinical importance and profound knowledge of the organogenesis and functional anatomy is imperative for the interpretation and evaluation of lung pathophysiology and subsequent surgical intervention. However, appreciating them on radiographs and CT scans is difficult and they are therefore often either not identified or completely misinterpreted. As presented in this case report, an accessory fissure separating the superior segment of the right lower lobe from its native lobe was seen perioperatively and could only retrospectively be defined on X-rays and CT scan. It is imperative to keep in mind that accessory fissures can be missed on imaging studies and thus can make the surgical procedure more challenging. PMID:26185701

  15. Marginal Microleakage of Conventional Fissure Sealants and Self-Adhering Flowable Composite as Fissure Sealant in Permanent Teeth

    PubMed Central

    Rahimian-Imam, Sara; Fayazi, Mohammad Reza

    2015-01-01

    Objectives: Application of sealants is a safe and effective way to prevent occlusal caries in the posterior teeth. A successful sealant therapy depends on good isolation. Decreased steps of adhesive application may enable proper isolation and use of self-adhering flowable composites for sealant therapy. This study sought to compare the marginal microleakage of fissure sealants and self-adhering flowable composites in permanent teeth. Materials and Methods: This in vitro, experimental study was conducted on 60 extracted human premolar teeth. The teeth were divided randomly into two groups of 30. In the first group, fissure sealant (Clinpro, 3M ESPE, USA) was placed on the teeth. In the second group, self-adhering flowable composite (Vertise Flow, Kerr, USA) was applied as the sealant. Then, both groups were immersed in 0.5% fuchsin dye solution for 24 hours. Sectioned samples were observed with a stereomicroscope for the extent of dye penetration. Data were analyzed using SPSS 21 and the Mann-Whitney test (P<0.05). Results: Microleakage in the fissure sealant group was significantly higher than that in the self-adhering flowable composite group (P<0.001). Conclusion: Microleakage was less using self-adhering flowable composite compared to conventional fissure sealant; therefore, self-adhering flowable composite can be used as a suitable fissure sealant in permanent teeth. PMID:26884777

  16. Potential biomass in deep-sea hydrothermal vent ecosystem

    NASA Astrophysics Data System (ADS)

    Nakamura, K.; Takai, K.

    2012-12-01

    Since the first discovery of black smoker vents hosting chemosynthetic macrofaunal communities (Spiess et al., 1980), submarine hydrothermal systems and associated biota have attracted interest of many researchers (e.g., Humphris et al., 1995; Van Dover, 2000; Wilcock et al., 2004). In the past couple of decades, particular attention has been paid to chemolithoautotrophic microorganisms that sustain the hydrothermal vent-endemic animal communities as the primary producer. This type of microorganisms obtains energy from inorganic substances (e.g., sulfur, hydrogen, and methane) derived from hydrothermal vent fluids, and is often considered as an important modern analogue to the early ecosystems of the Earth as well as the extraterrestrial life in other planets and moons (e.g., Jannasch and Mottl, 1985; Nealson et al., 2005; Takai et al., 2006). Even today, however, the size of this type of chemosynthetic deep-sea hydrothermal vent ecosystem is largely unknown. Here, we present geophysical and geochemical constraints on potential biomass in the deep-sea hydrothermal vent ecosystem. The estimation of the potential biomass in the deep-sea hydrothermal vent ecosystem is based on hydrothermal fluid flux calculated from heat flux (Elderfield and Schltz, 1996), maximum chemical energy available from metabolic reactions during mixing between hydrothermal vent fluids and seawater (McCollom, 2007), and maintenance energy requirements of the chemolithoautotrophic microorganisms (Hoehler, 2004). The result shows that the most of metabolic energy sustaining the deep-sea hydrothermal vent ecosystem is produced by oxidation reaction of reduced sulfur, although some parts of the energy are derived from hydrogenotrophic and methanotrophic reactions. The overall total of the potential biomass in deep-sea hydrothermal vent ecosystem is calculated to be much smaller than that in terrestrial ecosystems including terrestrial plants. The big difference in biomass between the

  17. Pit and fissure sealant: review of the literature.

    PubMed

    Simonsen, Richard J

    2002-01-01

    For this literature review of pit and fissure sealant, 1,465 references were selected by a search for "sealants" on PubMed. References were limited to dental journals and papers in the English language. The search comprised papers from 1971 to October 2001. Additional papers of historical significance prior to 1971 were added from memory and from reference lists published in early papers. This paper reviewed the literature on pit and fissure sealants under the following subheadings: (1) laboratory studies, (2) clinical technique and tooth preparation, (3) etching time, (4) auxiliary application of pit and fissure sealant, (5) retention and caries prevention, (6) fluoride used with sealants and fluoride-containing sealant, (7) glass ionomer materials as sealants, (8) options in sealant: filled vs unfilled; colored vs clear; autocure vs light-initiated, (9) sealant placed over caries in a therapeutic manner, (10) cost effectiveness of sealant application, (11) underuse of pit and fissure sealant, (12) the estrogenicity issue, (13) use of an intermediate bonding layer to improve retention, (14) new developments and projections, and (15) summary and conclusions. From a careful and thorough review of peer-reviewed publications on pit and fissure sealant, it is clear that sealants are safe, effective and underused (at least underused in the United States). Pit and fissure sealant is best applied to high-risk populations by trained auxiliaries using sealant that incorporates the benefit of an intermediate bonding layer, applied under the rubber dam or with some alternative short-term, but effective, isolation technique, onto an enamel surface that has been cleaned with an air polishing technique and etched with 35% phosphoric acid for 15 seconds. The dental profession awaits with enthusiasm, and some impatience, the incorporation of dentin-bonding technology into the development of a modern, more durable, resin-based sealant. PMID:12412954

  18. Cement penetration after patella venting.

    PubMed

    Jones, Christopher W; Lam, Li-On; Butler, Adam; Wood, David J; Walsh, William R

    2009-01-01

    There is a high rate of patellofemoral complications following total knee arthroplasty. Optimization of the cement-bone interface by venting and suction of the tibial plateau has been shown to improve cement penetration. Our study was designed to investigate if venting the patella prior to cementing improved cement penetration. Ten paired cadaver patellae were allocated prior to resurfacing to be vented or non-vented. Bone mineral density (BMD) was measured by DEXA scanning. In vented specimens, a 1.6 mm Kirschner wire was used to breach the anterior cortex at the center. Specimens were resurfaced with standard Profix instrumentation and Versabond bone cement (Smith and Nephew PLC, UK). Cement penetration was assessed from Faxitron and sectioned images by a digital image software package (ImageJ V1.38, NIH, USA). Wilcoxon rank sum test was used to assess the difference in cement penetration between groups. The relationship between BMD and cement penetration was analyzed by Pearson correlation coefficient. There was a strong negative correlation between peak BMD and cement penetration when analyzed independent of experimental grouping (r(2)=-0.812, p=0.004). Wilcoxon rank sum testing demonstrated no significant difference (rank sum statistic W=27, p=0.579) in cement penetration between vented (10.53%+/-4.66; mean+/-std dev) and non-vented patellae (11.51%+/-6.23; mean+/-std dev). Venting the patella using a Kirschner wire does not have a significant effect on the amount of cement penetration achieved in vitro using Profix instrumentation and Versabond cement. PMID:19010682

  19. On small disturbance ascent vent behavior

    NASA Astrophysics Data System (ADS)

    Woronowicz, M. S.

    2012-10-01

    As a spacecraft undergoes ascent in a launch vehicle, its ambient pressure environment transitions from one atmosphere to high vacuum in a matter of a few minutes. Venting of internal cavities is necessary to prevent the buildup of pressure differentials across cavity walls. These pressure differentials are often restricted to low levels to prevent violation of container integrity. Such vents usually consist of fixed orifices, ducts, or combinations of both. Duct conductance behavior is fundamentally different from that for orifices in pressure driven flows governing the launch vehicle ascent depressurization environment. Duct conductance is governed by the average pressure across its length, while orifice conductance is dictated by a pressure ratio. Hence, one cannot define a valid "equivalent orifice" for a given duct across a range of pressure levels. The purpose of this paper is to develop expressions for these two types of vent elements in the limit of small pressure differentials, explore conditions for their validity, and to compare features regarding ascent depressurization performance.

  20. 2D models of gas flow and ice grain acceleration in Enceladus' vents using DSMC methods

    NASA Astrophysics Data System (ADS)

    Tucker, Orenthal J.; Combi, Michael R.; Tenishev, Valeriy M.

    2015-09-01

    The gas distribution of the Enceladus water vapor plume and the terminal speeds of ejected ice grains are physically linked to its subsurface fissures and vents. It is estimated that the gas exits the fissures with speeds of ∼300-1000 m/s, while the micron-sized grains are ejected with speeds comparable to the escape speed (Schmidt, J. et al. [2008]. Nature 451, 685-688). We investigated the effects of isolated axisymmetric vent geometries on subsurface gas distributions, and in turn, the effects of gas drag on grain acceleration. Subsurface gas flows were modeled using a collision-limiter Direct Simulation Monte Carlo (DSMC) technique in order to consider a broad range of flow regimes (Bird, G. [1994]. Molecular Gas Dynamics and the Direct Simulation of Gas Flows. Oxford University Press, Oxford; Titov, E.V. et al. [2008]. J. Propul. Power 24(2), 311-321). The resulting DSMC gas distributions were used to determine the drag force for the integration of ice grain trajectories in a test particle model. Simulations were performed for diffuse flows in wide channels (Reynolds number ∼10-250) and dense flows in narrow tubular channels (Reynolds number ∼106). We compared gas properties like bulk speed and temperature, and the terminal grain speeds obtained at the vent exit with inferred values for the plume from Cassini data. In the simulations of wide fissures with dimensions similar to that of the Tiger Stripes the resulting subsurface gas densities of ∼1014-1020 m-3 were not sufficient to accelerate even micron-sized ice grains to the Enceladus escape speed. In the simulations of narrow tubular vents with radii of ∼10 m, the much denser flows with number densities of 1021-1023 m-3 accelerated micron-sized grains to bulk gas speed of ∼600 m/s. Further investigations are required to understand the complex relationship between the vent geometry, gas source rate and the sizes and speeds of ejected grains.

  1. Hemorrhoids and anal fissures in inflammatory bowel disease.

    PubMed

    D'Ugo, S; Stasi, E; Gaspari, A L; Sileri, P

    2015-12-01

    Perianal disease is a common complication of inflammatory bowel disease (IBD). It includes different conditions from more severe and potentially disabling ones, such as abscesses and fistulas, to more benign conditions such as hemorrhoids, skin tags and fissures. Most literature has been focused on anal sepsis and fistulae, as they carry the majority of disease burden and often alter the natural course of the disease. Hemorrhoids and anal fissures in patients with IBD have been overlooked, although they can represent a challenging problem. The management of hemorrhoids and fissures in IBD patients may be difficult and may significantly differ compared to the non-affected population. Historically surgery was firmly obstructed, and hemorrhoidectomy or sphincterotomy in patients with associated diagnosis of IBD was considered harmful, although literature data is scant and based on small series. Various authors reported an incidence of postoperative complications higher in IBD than in the general populations, with potential severe events. Considering that a spontaneous healing is possible, the first line management should be a medical therapy. In patients non-responding to conservative measures it is possible a judicious choice of surgical options on a highly selective basis; this can lead to acceptable results, but the risk of possible complications needs to be considered. In this review it is analyzed the current literature on the incidence, symptoms and treatment options of hemorrhoids and anal fissures in patients with Crohn's disease and ulcerative colitis. PMID:26446683

  2. Dental Pit and Fissure Sealants: Implications for School Health Personnel.

    ERIC Educational Resources Information Center

    McCormack-Brown, K. R.; And Others

    1989-01-01

    To promote good personal hygiene practices in students, school health personnel must be informed about dental pit and fissure sealants and related programs. Adoption and maintenance of such programs may depend on the success of school health personnel in educating administrators and policymakers. (SM)

  3. High-Resolution Micro-Bathymetry Mapping in the Lau Basin: Examples From the Tui Malila and Mariner Vent Sites

    NASA Astrophysics Data System (ADS)

    Ferrini, V.; Sterling, A.; Martinez, F.; Tivey, M. K.; Mottl, M.; Kim, S.

    2005-12-01

    High-resolution SM2000 (200 kHz) multibeam sonar data were collected at six vent areas on the Lau Basin spreading center in April 2005. Data were acquired during near-bottom surveys conducted with the ROV Jason II at altitudes ranging from 5 to 20 m. High altitude (20 m) bathymetric surveys were complemented by near-bottom visual surveys, which provided ground-truth observations of the seafloor. Combined with Doppler and Long Baseline (LBL) Navigation, these bathymetry data provide sub-meter resolution of seafloor features, and reveal individual vent structures, faults and fissures. We present bathymetry data from two sites located 22 km apart, which are geologically and biologically distinct and exhibit contrasts in venting styles and biota. The Mariner vent field contains massive vent structures, many of which are taller than 25 m, with active venting from their bases and sides. Fluids exit as vigorous, high-temperature (< 363°C) black smoker fluids through chalcopyrite-lined conduits, and as less focused flow from porous beehive structures. Inactive structures are friable and are composed of iron- and copper-oxides. There was little evidence of faulting or fracture at the vent field, but we note the presence of collapsed volcanic dome structures. The vent fauna at Mariner is very limited; only Bythograeid and Galatheid crabs, and one Brisingid Seastar, were found. Tui Malila, by contrast, is characterized by shorter and wider branched vent structures with coalesced spires, the tops of which were actively venting. There is extensive faulting and fracture at this site, as well as a number of large flanges and areas of diffuse flow. At Tui Malila fluids exit tall structures through chalcopyrite- and zinc-lined conduits (at temperatures < 312°C), from beneath flanges, and directly from andesite. Hydrothermal breccias are also present. Tui Malila hosts a more typical vent community, with greater abundances of both Bythograeid and Galatheid crabs, mostly within 4 m

  4. Selection for fissure resistance now made possible in early breeding generations

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Rice kernel fissuring is one of the leading causes of milling yield losses. Any reduction in fissuring can result in direct increases in yield and profit for both producers and millers. While most U.S. rice varieties yield around 55% head rice, the fissure-resistant varieties ‘Cypress’, ‘Saber’ an...

  5. Numerical modeling of the evolution of two-phase zone under fissured caprock

    SciTech Connect

    Yano, Y.; Ishido, T.

    1993-01-28

    A vapor-dominated two-phase zone would be formed in a geothermal reservoir under fissured caprock, if the permeability of the fissure is much smaller than a critical permeability which is estimated by an energy balance. If the permeability of the fissure is large, then the rule of minimum mass input would be applied.

  6. New method opens opportunity to proactively select for fissure resistance in early breeding generations

    Technology Transfer Automated Retrieval System (TEKTRAN)

    WANTED: New rice varieties improved for resistance to kernel fissuring. Rice kernel fissuring is one of the leading causes of reduced milling yield. Any reduction in fissuring can result in direct increases in yield and profit for both producers and millers. While most U.S. rice varieties yield a...

  7. Complete genome sequence of the thermophilic sulfur-reducer Desulfurobacterium thermolithotrophum type strain (BSAT) from a deep-sea hydrothermal vent

    SciTech Connect

    Goker, Markus; Daligault, Hajnalka E.; Mwirichia, Romano; Lapidus, Alla L.; Deshpande, Shweta; Pagani, Ioanna; Tapia, Roxanne; Cheng, Jan-Fang; Goodwin, Lynne A.; Pitluck, Sam; Liolios, Konstantinos; Ivanova, N; Mavromatis, K; Mikhailova, Natalia; Pati, Amrita; Chen, Amy; Palaniappan, Krishna; Han, Cliff; Land, Miriam L; Hauser, Loren John; Pan, Chongle; Brambilla, Evelyne-Marie; Rohde, Manfred; Spring, Stefan; Sikorski, Johannes; Wirth, Reinhard; Detter, J. Chris; Woyke, Tanja; Bristow, James; Eisen, Jonathan; Markowitz, Victor; Hugenholtz, Philip; Kyrpides, Nikos C; Klenk, Hans-Peter

    2011-01-01

    Desulfurobacterium thermolithotrophum L'Haridon et al. 1998 is the type species of the ge- nus Desulfurobacterium which belongs to the family Desulfurobacteriaceae. The species is of interest because it represents the first thermophilic bacterium that can act as a primary pro- ducer in the temperature range of 45-75 C (optimum 70 C) and is incapable of growing un- der microaerophilic conditions. Strain BSAT preferentially synthesizes high-melting-point fatty acids (C18 and C20) which is hypothesized to be a strategy to ensure the functionality of the membrane at high growth temperatures. This is the second completed genome sequence of a member of the family Desulfurobacteriaceae and the first sequence from the genus Desulfu- robacterium. The 1,541,968 bp long genome harbors 1,543 protein-coding and 51 RNA genes and is a part of the Genomic Encyclopedia of Bacteria and Archaea project.

  8. Modeling of zero gravity venting

    NASA Technical Reports Server (NTRS)

    Merte, H., Jr.

    1984-01-01

    The venting of cylindrical containers partially filled with initially saturated liquids was conducted under zero gravity conditions and compared with an analytical model which determined the effect of interfacial mass transfer on the ullage pressure response during venting. A model is proposed to improve the estimation of the interfacial mass transfer. Duhammel's superposition integral is incorporated in this analysis to approximate the transient temperature response of the interface, treating the liquid as a semiinfinite solid with conduction heat transfer. This approach to estimating interfacial mass transfer gives improved response when compared to previous models. The model still predicts a pressure decrease greater than those in the experiments reported.

  9. Reactor pressure vessel vented head

    DOEpatents

    Sawabe, James K.

    1994-01-11

    A head for closing a nuclear reactor pressure vessel shell includes an arcuate dome having an integral head flange which includes a mating surface for sealingly mating with the shell upon assembly therewith. The head flange includes an internal passage extending therethrough with a first port being disposed on the head mating surface. A vent line includes a proximal end disposed in flow communication with the head internal passage, and a distal end disposed in flow communication with the inside of the dome for channeling a fluid therethrough. The vent line is fixedly joined to the dome and is carried therewith when the head is assembled to and disassembled from the shell.

  10. Double-Porosity Models for a Fissured Groundwater Reservoir With Fracture Skin

    NASA Astrophysics Data System (ADS)

    Moench, Allen F.

    1984-07-01

    Theories of flow to a well in a double-porosity groundwater reservoir are modified to incorporate effects of a thin layer of low-permeability material or fracture skin that may be present at fracture-block interfaces as a result of mineral deposition or alteration. The commonly used theory for flow in double- porosity formations that is based upon the assumption of pseudo-steady state block-to-fissure flow is shown to be a special case of the theory presented in this paper. The latter is based on the assumption of transient block-to-fissure flow with fracture skin. Under conditions where fracture skin has a hydraulic conductivity that is less than that of the matrix rock, it may be assumed to impede the interchange of fluid between the fissures and blocks. Resistance to flow at fracture-block interfaces tends to reduce spatial variation of hydraulic head gradients within the blocks. This provides theoretical justification for neglecting the divergence of flow in the blocks as required by the pseudo-steady state flow model. Coupled boundary value problems for flow to a well discharging at a constant rate were solved in the Laplace domain. Both slab-shaped and sphere-shaped blocks were considered, as were effects of well bore storage and well bore skin. Results obtained by numerical inversion were used to construct dimensionless-type curves that were applied to well test data, for a pumped well and for an observation well, from the fractured volcanic rock terrane of the Nevada Test Site.

  11. 14 CFR 29.975 - Fuel tank vents and carburetor vapor vents.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 14 Aeronautics and Space 1 2013-01-01 2013-01-01 false Fuel tank vents and carburetor vapor vents. 29.975 Section 29.975 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION AIRCRAFT AIRWORTHINESS STANDARDS: TRANSPORT CATEGORY ROTORCRAFT Powerplant Fuel System § 29.975 Fuel tank vents and carburetor vapor vents....

  12. 14 CFR 25.975 - Fuel tank vents and carburetor vapor vents.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 14 Aeronautics and Space 1 2013-01-01 2013-01-01 false Fuel tank vents and carburetor vapor vents. 25.975 Section 25.975 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION AIRCRAFT AIRWORTHINESS STANDARDS: TRANSPORT CATEGORY AIRPLANES Powerplant Fuel System § 25.975 Fuel tank vents and carburetor vapor vents....

  13. Monitoring of the volcanic rock compositions during the 2012-2013 fissure eruption at Tolbachik volcano, Kamchatka

    NASA Astrophysics Data System (ADS)

    Volynets, Anna O.; Edwards, Benjamin R.; Melnikov, Dmitry; Yakushev, Anton; Griboedova, Irina

    2015-12-01

    Here we present the results from monitoring of the composition of rocks produced during the 2012-2013 fissure eruption at Tolbachik volcano (FTE). Major and trace element concentrations in 75 samples are reported. Products of this eruption are represented by high alumina basaltic trachyandesites with higher alkalis and titanium contents than in all previously studied rocks of the Tolbachik monogenetic volcanic field. Rocks erupted during the first three days (27-30 November) from the northern (also called Menyailov) group of vents are the most silica- and alkali-rich (SiO2 concentrations up to 55.35 wt.% and K2O up to 2.67 wt.%). From December onwards, when the eruptive activity switched from the Menyailov vents to the southern (Naboko) group of vents, silica content dropped by 2 wt.%, concentrations of MgO, FeO, TiO2 and Mg# increased, and K2O and Na2O concentrations and K2O/MgO ratio decreased. For the rest of the eruption the compositions of rocks remained constant and homogeneous; no systematic compositional differences between lava, bombs and scoria samples are evident. Trace element distributions in the rocks of the Menyailov and Naboko vent lavas are relatively uniform; Menyailov lavas have slightly higher Th, Nb, Hf, Y, and HREE concentrations than the Naboko vent lavas at more or less constant element ratios. We explain the initial change in geochemistry by tapping of a slightly cooler and fractionated (~ 3% Mt and 8% Cpx) upper part of the magma storage zone before the main storage area began to feed the eruption. Thermodynamic constraints show that apparent liquidus temperatures varied from 1142 °C to 1151 °C, and thermodynamic modeling shows that variations in compositions are consistent with a high degree of low pressure (100-300 MPa), nominally anhydrous fractionation of a parent melt compositionally similar to the 1975 Northern Breakthrough high-Mg basalt. Geochemistry, petrological observations and modeling are in agreement with the newly erupted

  14. A Computational Geometry Approach to Automated Pulmonary Fissure Segmentation in CT Examinations

    PubMed Central

    Pu, Jiantao; Leader, Joseph K; Zheng, Bin; Knollmann, Friedrich; Fuhrman, Carl; Sciurba, Frank C; Gur, David

    2010-01-01

    Identification of pulmonary fissures, which form the boundaries between the lobes in the lungs, may be useful during clinical interpretation of CT examinations to assess the early presence and characterization of manifestation of several lung diseases. Motivated by the unique nature of the surface shape of pulmonary fissures in three-dimensional space, we developed a new automated scheme using computational geometry methods to detect and segment fissures depicted on CT images. After a geometric modeling of the lung volume using the Marching Cube Algorithm, Laplacian smoothing is applied iteratively to enhance pulmonary fissures by depressing non-fissure structures while smoothing the surfaces of lung fissures. Next, an Extended Gaussian Image based procedure is used to locate the fissures in a statistical manner that approximates the fissures using a set of plane “patches.” This approach has several advantages such as independence of anatomic knowledge of the lung structure except the surface shape of fissures, limited sensitivity to other lung structures, and ease of implementation. The scheme performance was evaluated by two experienced thoracic radiologists using a set of 100 images (slices) randomly selected from 10 screening CT examinations. In this preliminary evaluation 98.7% and 94.9% of scheme segmented fissure voxels are within 2 mm of the fissures marked independently by two radiologists in the testing image dataset. Using the scheme detected fissures as reference, 89.4% and 90.1% of manually marked fissure points have distance ≤ 2 mm to the reference suggesting a possible under-segmentation of the scheme. The case-based RMS (root-mean-square) distances (“errors”) between our scheme and the radiologist ranged from 1.48±0.92 to 2.04±3.88 mm. The discrepancy of fissure detection results between the automated scheme and either radiologist is smaller in this dataset than the inter-reader variability. PMID:19272987

  15. The effect of vegetation on infiltration in shallow soils underlain by fissured bedrock

    NASA Astrophysics Data System (ADS)

    Stothoff, S. A.; Or, D.; Groeneveld, D. P.; Jones, S. B.

    1999-05-01

    Mean annual infiltration above the high-level waste repository proposed to be sited at Yucca Mountain, Nevada, has a large impact on assessments of repository performance. Ongoing investigations of infiltration processes have identified the relatively horizontal caprock environment above portions of the repository as a potentially large source of infiltrating waters, due to shallow, permeable soils above a moderately welded tuff with large soil-filled fissures. The combination of shallow soils and fissured bedrock allows rapid penetration of wetting pulses to below the rooting zone. Plant uptake can strongly reduce net infiltration in arid environments with high water storage capacity, and, despite the low water storage capacity, there is a relatively high vegetation density in this environment. The apparent discrepancy between high vegetation density and low water storage motivates the study of plant-hydrologic interactions in this semiarid environment. Field observations were coupled with plant- and landscape-scale models to provide insight into plant-hydrologic interactions. Several lines of evidence, including: (i) linear plant growth features observed on aerial photographs; (ii) comparisons of plant cover within the fissured environment and comparable environments lacking fissures; and (iii) direct excavations, all suggest that the widely spaced soil-filled fissures are conducive to plant growth even when fissures are buried at soil depths exceeding 30 cm. Results from a mechanistic simulation model for root growth into fissures suggest that the additional (sheltered) plant-available soil water within fissures provides a competitive advantage for plant establishment. Therefore, plants that germinate above a fissure are more likely to survive, in turn developing linear features above fissures. Having established that plants preferentially root within soil-filled fissures in the caprock environment, a set of simulations were performed to examine the hydrologic

  16. [Aortic intramural hematoma fissuration: atypical presentation in an aircraft pilot].

    PubMed

    Fozzato, Francesca; Prioli, Maria Antonia; Santini, Francesco; Menini, Fabio; Pavan, Michela; Guarise, Paola; Vassanelli, Corrado

    2010-02-01

    Aortic intramural hematoma is a life-threatening thoracic aortic pathology. In this report we describe a case of fissuration of an aortic intramural hematoma with atypical clinical presentation, which occurred in an aircraft pilot. The patient was admitted to our emergency room with transient chest pain developed during a flight landing, followed only by persistent abdominal pain. The ECG and cardiac enzymes were normal. A portable two-dimensional transthoracic echocardiogram showed aortic root dilation and pericardial effusion. Transesophageal echocardiography showed aortic intramural hematoma with fissuration into the pericardial space. The angio-computed tomography confirmed the diagnosis. Two hours after admission the patient, with signs of cardiac tamponade, underwent Bentall surgical intervention without complications. PMID:20408481

  17. Delayed Superior Orbital Fissure Syndrome After Reconstruction of Blowout Fracture.

    PubMed

    Kim, Young Joon; Choi, Woong Kyu

    2016-01-01

    The superior orbital fissure syndrome (SOFS) has been known to be a condition caused by impairment of the nerves that cross the superior orbital fissure. Traumatic SOFS is an uncommon complication which occurs usually within 48 hours after a facial injury. A 25-year-old male sustained facial trauma following an altercation. Clinical findings on presentation included swelling, ecchymosis, hyphema, subretinal hemorrhage, and mild extraocular movement limitation upon lateral gaze on his right eyelids. Facial computed tomography scan confirmed fractures of the medial walls of the right orbit and herniation of orbital soft tissue without the incarceration of medial rectus muscle. Ten days after the trauma, the operation was performed. On postoperative day 16, the patient showed ptosis of the right upper eyelid with a fixed pupil, and there was a hypoesthesia over the distribution of the right supraorbital and supratrochlear nerves. The authors diagnosed as a delayed SOFS and prescribed 4 mg of methylprednisolone q.i.d. for 30 days. After steroid therapy, extraocular movement limitations improved progressively. After 8 months, movement was completely restored. The authors experienced delayed SOFS on posttrauma day 27, and it was treated by steroid therapy. Surgical intervention is required when there is an evident etiology such as underlying hematoma or plate migration. If the reason is not clear like our case, steroid therapy can be considered as one of the options. Particularly, the authors should give special attention to the patient who has congenitally narrow superior orbital fissure, like Fujiwara et al suggested. PMID:26674904

  18. Effect of Different Vent Configurations on the Interruption Performance of Arc Chamber

    NASA Astrophysics Data System (ADS)

    Chen, Degui; Li, Xingwen; Dai, Ruicheng

    Gas flow in arc quenching chamber has an important effect on the interruption capability of low voltage circuit breakers. In this paper, based on a simplified model of arc chamber with a single break, which can be opened by the electro-dynamics repulsion force automatically, the effect of different vent configurations including middle vent and side vent on the interruption performance is investigated. First, the experiments are carried out to compare the different performance in the interruption process between middle vent type and side vent type. In addition, according to the experimental model, a 3-D magneto-hydrodynamic model was developed by adapting and modified the commercial computational fluid dynamics software FLUENT. The simulation results show the same trend in arc motion as explained in the experimental conclusions in theory.

  19. EXPOSED BEAM AND VINYL VENTED SOFFIT MATERIAL IN THE CARPORT ...

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

    EXPOSED BEAM AND VINYL VENTED SOFFIT MATERIAL IN THE CARPORT ON THE SOUTHEAST SIDE OF THE UNIT - Camp H.M. Smith and Navy Public Works Center Manana Title VII (Capehart) Housing, U-Shaped Two-Bedroom Single-Family Type 6, Birch Circle, Elm Drive, Elm Circle, and Date Drive, Pearl City, Honolulu County, HI

  20. Location of seismic events and eruptive fissures on the Piton de la Fournaise volcano using seismic amplitudes

    USGS Publications Warehouse

    Battaglia, J.; Aki, K.

    2003-01-01

    We present a method for locating the source of seismic events on Piton de la Fournaise. The method is based on seismic amplitudes corrected for station site effects using coda site amplification factors. Once corrected, the spatial distribution of amplitudes shows smooth and simple contours for many types of events, including rockfalls, long-period events and eruption tremor. On the basis of the simplicity of these distributions we develop inversion methods for locating their origins. To achieve this, the decrease of the amplitude as a function of the distance to the source is approximated by the decay either of surface or body waves in a homogeneous medium. The method is effective for locating rockfalls, long-period events, and eruption tremor sources. The sources of eruption tremor are usually found to be located at shallow depth and close to the eruptive fissures. Because of this, our method is a useful tool for locating fissures at the beginning of eruptions.

  1. Electrochemical cell having a safety vent closure

    SciTech Connect

    Zupancic, R.L.

    1982-05-11

    A safety blow-out vent closure for galvanic cells, such as nonaqueous oxyhalide cells, which comprises the employment of a conductive tubular member secured to the cell's housing and surrounding a vent orifice in the cell's housing and wherein a deformable member is force-fitted in said vent orifice and adapted to at least partially be ejected from the vent orifice upon the build up of a predetermined internal gas pressure within the cell. The invention is also directed to a method for assembling an electrochemical cell with the above-described safety vent closure.

  2. The fissure: interlobar collateral ventilation and implications for endoscopic therapy in emphysema

    PubMed Central

    Koster, Theodoor David; Slebos, Dirk-Jan

    2016-01-01

    In patients with severe emphysema, bronchoscopic lung volume reduction using one-way valves is a promising therapeutic option to improve lung function and quality of life. The goal of this treatment is to achieve a complete lobar atelectasis. In a significant proportion of patients, this atelectasis cannot be achieved due to interlobar collateral ventilation. This collateral ventilation is generated through incomplete lobar fissures. Therefore, only patients with complete fissures and no collateral ventilation can be selected for endobronchial therapy with one-way valves. Incomplete fissures are very common and exhibit a great variation in anatomy. The reported prevalence is 17%–85% for the right major fissure, 19%–74% for the left major fissure, and 20%–90% for the minor fissure. There are several methods of measuring or predicting the presence of collateral ventilation, with computed tomography (CT)-fissure analysis and the Chartis measurement being the most important. CT-fissure analysis is an indirect method to measure the completeness of fissures as a surrogate for collateral ventilation. The Chartis system is an endobronchial method to directly measure the presence of collateral ventilation. Both methods have unique value, and the combination of both can accurately predict the treatment response to the bronchoscopic placement of endobronchial valves. This review provides an in-depth view of lung fissure and collateral ventilation to help understand its importance in selecting the appropriate patients for new emphysema treatments and thus avoid useless treatment in unsuitable patients. PMID:27110109

  3. Giant desiccation fissures filled with calcareous eolian sand, Hermosa Formation (Pennsylvanian), southeastern Utah

    NASA Astrophysics Data System (ADS)

    Loope, David B.; Haverland, Zsolt E.

    1988-04-01

    At two stratigraphic intervals within the upper member of the Upper Pennsylvanian Hermosa Formation, calcareous eolian sand fills downward-tapering fissures that are as much as 18 cm wide and 5.7 m deep. Fissure fillings define orthogonal polygons 10 m or more in diameter. One of the host beds is primarily composed of subtidally deposited limestone, the other is a thinly laminated, nonmarine red siltstone. Both systems of fissure fillings are directly overlain and underlain by large-scale cross-stratified, calcareous eolianites. The limestone host bed contains chert pseudomorphs after gypsum. Compaction of host rocks contorted fissure fillings and caused doming of eolian strata over each fissure. Platy mineral grains in fissure fillings are aligned subparallel to bedding in the host rocks, supporting the view that the fissures were passively filled rather than forcefully injected. These ancient fissure systems are similar in scale and pattern to those that define giant desiccation polygons in numerous Great Basin playas. The Pennsylvanian fissures, like their Holocene counterparts, probably formed when groundwater tables dropped from shallow levels within fine-grained, impermeable deposits into underlying aquifers, greatly decreasing the extent of the capillary fringe. Our study of the fissures and host rocks supports the hypothesis that carbonate grains within the eolianites were deflated from uncemented marine sediments that were broadly exposed during regressive intervals.

  4. A Review of Cyanoacrylate Liquid Skin Protectant and Its Efficacy on Pedal Fissures

    PubMed Central

    Vlahovic, Tracey C.; Hinton, Elizabeth A.; Chakravarthy, Debashish; Fleck, Cynthia Ann

    2011-01-01

    Introduction Skin fissures are a common dermatologic condition caused by excessive dry skin, numerous systemic diseases, and backless shoe gear. They are defects in skin that fall into the category of damaged, partial-thickness skin wounds, as opposed to full-thickness wounds. Patients with heel fissures are at an increased risk for developing infection, which could cause more severe issues, especially in patients with diabetes and peripheral vascular disease. Methods Five patients from Temple Foot and Ankle Institute, Philadelphia, PA, with a total of 8 heel fissures and 2 hallux fissures, were studied. Patients were dispensed 9 vials of a cyanoacrylate liquid skin protectant (Marathon™, Medline Industries, Inc, Mundelein, IL) to be applied to the fissure every 3 days. Patients returned every 2 weeks for follow-up in clinic. Results The hallux fissures and 4 of the heel fissures went to complete closure after 2 weeks. There was an average decrease of 1.16 cm in length of the heel fissure dimensions after 2 weeks and an average decrease of 1.1 cm in length of the hallux fissures. Conclusion This novel skin protectant proved to be a comfortable, easy, and effective tool in aiding the resolution of pedal skin fissures. PMID:24527155

  5. Wear of two pit and fissure sealants in contact with primary teeth

    PubMed Central

    Galo, Rodrigo; Contente, Marta Maria Martins Giamatei; Borsatto, Maria Cristina

    2014-01-01

    Objectives: Wear simulations may provide an indication of the clinical performance of pit-and-fissure sealants when associated with primary teeth as counterbody, restricting the involved variables. The aim of this study was to evaluate wear of dental materials used as pit-and-fissure sealants in contact with primary teeth. Materials and Methods: A resinous sealant (Fluroshield®) and a resin-modified glass ionomer cement (Vitremer®) were selected in a post-plate design, using as counterbody primary tooth pins (4 × 4 × 2 mm) at 3 and 10 N vertical load, 1 Hz frequency, 900 wear cycles in artificial saliva (n = 15). Attrition coefficient values were obtained and the material and primary tooth volumes were analyzed. Data were analyzed statistically by ANOVA and Duncan's test (P < 0.05). Results: Fluroshield® presented the highest attrition coefficient values for the 3 N but these values decreased significantly for the 10 N load. The means for volume loss (3 mm) of the different samples after the wear test were not statistically different for the materials. The volume loss values for the primary teeth were statistically different and there was an increase in volume loss with the increase of the load applied in the wear tests. Conclusions: Differences were also observed with regard to the surface deformation characteristics. The wear rates of primary tooth enamel vary according to the type of material and the load applied during mastication. PMID:24966777

  6. Reactor pressure vessel vented head

    DOEpatents

    Sawabe, J.K.

    1994-01-11

    A head for closing a nuclear reactor pressure vessel shell includes an arcuate dome having an integral head flange which includes a mating surface for sealingly mating with the shell upon assembly therewith. The head flange includes an internal passage extending therethrough with a first port being disposed on the head mating surface. A vent line includes a proximal end disposed in flow communication with the head internal passage, and a distal end disposed in flow communication with the inside of the dome for channeling a fluid therethrough. The vent line is fixedly joined to the dome and is carried therewith when the head is assembled to and disassembled from the shell. 6 figures.

  7. Differences in recovery between deep-sea hydrothermal vent and vent-proximate communities after a volcanic eruption

    NASA Astrophysics Data System (ADS)

    Gollner, Sabine; Govenar, Breea; Arbizu, Pedro Martinez; Mills, Susan; Le Bris, Nadine; Weinbauer, Markus; Shank, Timothy M.; Bright, Monika

    2015-12-01

    Deep-sea hydrothermal vents and the surrounding basalt seafloor are subject to major natural disturbance events such as volcanic eruptions. In the near future, anthropogenic disturbance in the form of deep-sea mining could also significantly affect the faunal communities of hydrothermal vents. In this study, we monitor and compare the recovery of insular, highly productive vent communities and vent-proximate basalt communities following a volcanic eruption that destroyed almost all existing communities at the East Pacific Rise, 9°50‧N in 2006. To study the recovery patterns of the benthic communities, we placed settlement substrates at vent sites and their proximate basalt areas and measured the prokaryotic abundance and compared the meio- and macrofaunal species richness and composition at one, two and four years after the eruption. In addition, we collected samples from the overlying water column with a pelagic pump, at one and two years after the volcanic eruption, to determine the abundance of potential meiofauna colonisers. One year after eruption, mean meio- and macrofaunal abundances were not significantly different from pre-eruption values in vent habitats (meio: 8-1838 ind. 64 cm-2 in 2006; 3-6246 ind. 64 cm-2 in 2001/02; macro: 95-1600 ind. 64 cm-2 in 2006; 205-4577 ind. 64 cm-2 in 2001/02) and on non-vent basalt habitats (meio: 10-1922 ind. 64 cm-2 in 2006; 8-328 ind. 64 cm-2 in 2003/04; macro: 14-3351 ind. 64 cm-2 in 2006; 2-63 ind. 64 cm-2 in 2003/04), but species recovery patterns differed between the two habitat types. In the vent habitat, the initial community recovery was relatively quick but incomplete four years after eruption, which may be due to the good dispersal capabilities of vent endemic macrofauna and vent endemic dirivultid copepods. At vents, 42% of the pre-eruption meio- and 39% of macrofaunal species had returned. In addition, some new species not evident prior to the eruption were found. At the tubeworm site Tica, a total of 26

  8. Assessing the atmospheric and climatic effects of basaltic fissure eruptions. A case study Nornahraun, North Iceland, 2014-2015.

    NASA Astrophysics Data System (ADS)

    Gallagher, Catherine; Burton, Kevin; Thordarson, Thorvaldur; Vye-Brown, Charlotte; Brown, Richard

    2015-04-01

    A volcanic eruption's ability to release sulphur gases into the atmosphere is one of the critical factors in assessing their climatic and environmental effects, because it is directly linked to the potential H2SO4 aerosol burden produced [1]. Basaltic fissure eruptions loft large amounts of sulphur into the atmosphere because of the efficient degassing of volatiles and halogens from the magma at the vent [2-4] coupled with the high sulphur yield of basaltic magma. The common nature of this style of eruption and its products, regardless of magnitude, means that our understanding of the exact processes which influence atmospheric chemistry and environmental impact is very important. The Nornahraun fissure eruption in North Iceland that began on the 31st August 2014, has quickly become one of the best documented eruptions of its kind, through systematic monitoring and sampling by the Institute of Earth Sciences eruption team and The Icelandic Meteorological Office. As a result it is an excellent modern analogue for historic or ancient basaltic fissure eruptions, for which the amount of degassing can only be estimated through petrological and geochemical methods. It also serves as a timely testing platform for novel geochemical proxies. This study uses the exceptional sensitivity of the 187Os-187Re radiogenic system to the presence of crustal material [5], and highly siderophile stable isotopes Cu, Zn and S to indicate the chemistry and degassing of the melt carrying S to the surface. The geochemical isotopic proxies will be tested using established petrological methods and gas emission data. This study concentrates on determining the following key parameters: (1) The source of volatiles in the magma indicated though the pressure dependence of S solubility. (2) The mechanism of aerosol and gas release into the atmosphere is dictated both by the chemistry of the melt that controls the S species (H2S, SO2 or FeS2) present [6], and by the mechanism of transfer. (3) The

  9. Tectonic and magmatic controls on the location of post-subduction monogenetic volcanoes in Baja California, Mexico, revealed through spatial analysis of eruptive vents

    NASA Astrophysics Data System (ADS)

    Germa, Aurélie; Connor, Laura J.; Cañon-Tapia, Edgardo; Le Corvec, Nicolas

    2013-12-01

    Post-subduction (12.5 Ma to less than 1 Ma) monogenetic volcanism on the Baja California peninsula, Mexico, formed one of the densest intra-continental areas of eruptive vents on Earth. It includes about 900 vents within an area ˜700 km long (N-S) and 70 to 150 km wide (W-E). This study shows that post-subduction volcanic activity was distributed along this arc and that modes exist in the volcano distribution, indicating that productivity of the magma source region was not uniform along the length of the arc. Vent clustering, vent alignments, and cone elongations were measured within eight monogenetic volcanic fields located along the peninsula. Results indicate that on a regional scale, vent clustering varies from north to south with denser spatial clustering in the north on the order of 1.9 × 10-1 vents/km2 to less dense clustering in the south on the order of 7.8 × 10-2 vents/km2. San Quintin, San Carlos, Jaraguay, and Santa Clara are spatially distinct volcanic fields with higher eruptive vent densities suggesting the existence of individual melt columns that may have persisted over time. In contrast, the San Borja, Vizcaino, San Ignacio, and La Purisima vent fields show lower degrees of vent clustering and no obvious spatial gaps between fields, thus indicating an area of more distributed volcanism. Insight into the lithospheric stress field can be gained from vent alignments and vent elongation measurements. Within the fields located along the extinct, subduction-related volcanic arc, elongation patterns of cinder cones and fissure-fed spatter cones, vent clusters, and vent alignments trend NW-SE and N-S. Within the Santa Clara field, located more to the west within the forearc, elongation patterns of the same volcanic features trend NE-SW. These patterns suggest that magmatism was more focused in the forearc and in the northern part of Baja California than in its southern region. Within the extinct arc, magma ascent created volcano alignments and elongate

  10. Evidence for a Chemoautotrophically Based Food Web at Inactive Hydrothermal Vents (Manus Basin)

    NASA Astrophysics Data System (ADS)

    van Dover, C. L.; Erickson, K.; Macko, S.

    2008-12-01

    Hydrothermal vents are ephemeral systems. When venting shuts down, sulfide-dependent taxa die off, and non-vent taxa can colonize the hard substrata. In Manus Basin (Papua New Guinea), where active and inactive sulfide mounds are interspersed, hydroids, cladorhizid sponges, barnacles, and bamboo sponges, and other invertebrate types may occupy inactive sulfide mounds. Carbon and nitrogen isotopic compositions of animals occupying inactive sulfide mounds are consistent with nutritional dependence on either chemoautotrophically or photosynthetically produced organic material, but sulfur isotopic compositions of these animals point to a chemoautotrophic source of sulfur from dissolved sulfide in vent fluids rather than sulfur derived from seawater sulfate through photosynthesis. Given that suspension-feeding and micro- carnivorous invertebrates are the biomass dominants at inactive sulfide mounds, the primary source of chemoautotrophic nutrition is likely suspended particulates and organisms delivered from nearby active vents.

  11. Evidence for a chemoautotrophically based food web at inactive hydrothermal vents (Manus Basin)

    NASA Astrophysics Data System (ADS)

    Erickson, K. L.; Macko, S. A.; Van Dover, C. L.

    2009-09-01

    Hydrothermal vents are ephemeral systems. When venting shuts down, sulfide-dependent taxa die off, and non-vent taxa can colonize the hard substrata. In Manus Basin (Papua New Guinea), where hydrothermally active and inactive sites are interspersed, hydroids, cladorhizid sponges, barnacles, bamboo corals, and other invertebrate types may occupy inactive sites. Carbon and nitrogen isotopic compositions of animals occupying inactive sites are consistent with nutritional dependence on either chemoautotrophically or photosynthetically produced organic material, but sulfur isotopic compositions of these animals point to a chemoautotrophic source of sulfur from dissolved sulfide in vent fluids rather than sulfur derived from seawater sulfate through photosynthesis. Given that suspension-feeding and micro-carnivorous invertebrates are the biomass dominants at inactive sites, the primary source of chemoautotrophic nutrition is likely suspended particulates and organisms delivered from nearby active vents.

  12. Endemic hydrothermal vent species identified in the open ocean seed bank.

    PubMed

    Gonnella, Giorgio; Böhnke, Stefanie; Indenbirken, Daniela; Garbe-Schönberg, Dieter; Seifert, Richard; Mertens, Christian; Kurtz, Stefan; Perner, Mirjam

    2016-01-01

    Hydrothermal vent systems host microbial communities among which several microorganisms have been considered endemic to this type of habitat. It is still unclear how these organisms colonize geographically distant hydrothermal environments. Based on 16S rRNA gene sequences, we compare the bacterial communities of sixteen Atlantic hydrothermal vent samples with our own and publicly available global open ocean samples. Analysing sequences obtained from 63 million 16S rRNA genes, the genera we could identify in the open ocean waters contained 99.9% of the vent reads. This suggests that previously observed vent exclusiveness is, in most cases, probably an artefact of lower sequencing depth. These findings are a further step towards elucidating the role of the open ocean as a seed bank. They can explain the predicament of how species expected to be endemic to vent systems are able to colonize geographically distant hydrothermal habitats and contribute to our understanding of whether 'everything is really everywhere'. PMID:27573109

  13. Enamel fusion using a carbon dioxide laser: A technique for sealing pits and fissures

    SciTech Connect

    Walsh, L.J.; Perham, S.J. )

    1991-05-01

    The well-established enhanced resistance of lased enamel to demineralization is the basis for clinical application of the carbon dioxide laser to caries prevention. This in vitro study examined the effect of focused infrared laser radiation on sound enamel and early pit and fissure caries. Low power levels (2-5 W) induced localized melting and resolidification of enamel with little surface destruction. For sound fissures, fusion of enamel from the lateral walls of the fissure eliminated the fissure space, providing a sealant effect; while in carious fissures, carious enamel was vaporized and adjacent sound enamel fused to partially eliminate the defect. The technique for enamel fusion using CO2 lasers has potential application for sealing pits and fissures and producing physicochemical alterations in enamel which may have preventive benefits.

  14. Comparative study of vent and seep macrofaunal communities in the Guaymas Basin

    NASA Astrophysics Data System (ADS)

    Portail, M.; Olu, K.; Escobar-Briones, E.; Caprais, J. C.; Menot, L.; Waeles, M.; Cruaud, P.; Sarradin, P. M.; Godfroy, A.; Sarrazin, J.

    2015-09-01

    Understanding the ecological processes and connectivity of chemosynthetic deep-sea ecosystems requires comparative studies. In the Guaymas Basin (Gulf of California, Mexico), the presence of seeps and vents in the absence of a biogeographic barrier, and comparable sedimentary settings and depths offers a unique opportunity to assess the role of ecosystem-specific environmental conditions on macrofaunal communities. Six seep and four vent assemblages were studied, three of which were characterised by common major foundation taxa: vesicomyid bivalves, siboglinid tubeworms and microbial mats. Macrofaunal community structure at the family level showed that density, diversity and composition patterns were primarily shaped by seep- and vent-common abiotic factors including methane and hydrogen sulfide concentrations, whereas vent environmental specificities (higher temperature, higher metal concentrations and lower pH) were not significant. The type of substratum and the heterogeneity provided by foundation species were identified as additional structuring factors and their roles were found to vary according to fluid regimes. At the family level, seep and vent similarity reached at least 58 %. All vent families were found at seeps and each seep-specific family displayed low relative abundances (< 5 %). Moreover, 85 % of the identified species among dominant families were shared between seep and vent ecosystems. This study provides further support to the hypothesis of continuity among deep-sea seep and vent ecosystems.

  15. Temporal change in megafauna at the Rose Garden hydrothermal vent (Galapagos Rift; eastern tropical Pacific)

    NASA Astrophysics Data System (ADS)

    Hessler, Robert R.; Smithey, William M.; Boudrias, Michel A.; Keller, Clifford H.; Lutz, Richard A.; Childress, James J.

    1988-10-01

    Hydrothermal vent communities must undergo substantial temporal change because of their dynamic physical milieu. This was verified in March 1985, when the Rose Garden hydrothermal vent on the Galapagos Rift was revisited after 5 1/4 years' absence. Comparison of photographs from the two visits revealed considerable faunal change. Among the hosts to chemoautotrophic bacteria, vestimentiferans were reduced from dominance to very low numbers. The mytilid was now extremely abundant and dominated vent openings. Vesicomyids also were more abundant. In general, vent-field suspension feeders had declined; anemones were distinctly less abundant, and siphonophores and enteropneusts were virtually absent. The decline of serpulids was likely, but less obvious. Of the mobile scavengers and carnivores, both galatheids and whelks were distincly more common. These community changes appear to result from both continuing recruitment and changes in the physical milieu. While the growth of some populations could have resulted from expanding opportunities, the population of at least one, the vesicomyid, had not achieved carrying capacity in 1979, and this could have pertained to others as well. The decrease of vestimentiferans may have been caused by declining vent-water flux, a process that would favor mytilids, or more complete vent-water filtration by the mytilids themselves. The same factors also could explain the reduction of vent-field filter feeders. These observations suggest that early stages in the cycle of Galapagos-type vent communities are likely to be dominated by vestimentiferans, but that bivalves will replace them with time.

  16. Joints, fissures, and voids in rhyolite welded ash-flow tuff at Teton damsite, Idaho

    USGS Publications Warehouse

    Prostka, Harold J.

    1977-01-01

    Several kinds of joints, fissures, and voids are present in densely welded rhyolite ash-flow tuff at Teton damsite. Older fissures and voids probably were formed in the ash-flow sheet during secondary flowage, which probably was caused by differential compaction or settling over irregular topography. The younger, more abundant fissures are mostly steep cooling joints that probably have been opened farther by horizontal tectonic extension and gravitational creep, perhaps aided by lateral stress relief.

  17. Caries-preventive effect of fissure sealants: a systematic review.

    PubMed

    Mejàre, Ingegerd; Lingström, Peter; Petersson, Lars G; Holm, Anna-Karin; Twetman, Svante; Källestål, Carina; Nordenram, Gunilla; Lagerlöf, Folke; Söder, Birgitta; Norlund, Anders; Axelsson, Susanna; Dahlgren, Helena

    2003-12-01

    The objectives of this study were to evaluate systematically the evidence of the caries-preventive effect of fissure sealing of occlusal tooth surfaces and to examine factors potentially modifying the effect. The search strategies included electronic databases, reference lists of articles, and selected textbooks. Inclusion criteria were randomized or quasi-randomized clinical trials or controlled clinical trials comparing fissure sealing with no treatment or another preventive treatment in children up to 14 years of age at the start; the outcome measure was caries increment; the diagnostic criteria had been described; and the follow-up time was at least 2 years. Inclusion decisions were taken and grading of the studies was done independently by two of the authors. The main measure of effect was relative risk reduction. Thirteen studies using resin-based or glass ionomer sealant materials were included in the final analysis. The results showed that most studies were performed during the 1970s and a single application had been utilized. The relative caries risk reduction pooled estimate of resin-based sealants on permanent 1st molars was 33% (relative risk = 0.67; CI = 0.55-0.83). The effect depended on retention of the sealant. In conclusion, the review suggests limited evidence that fissure sealing of 1st permanent molars with resin-based materials has a caries-preventive effect. The evidence is incomplete for permanent 2nd molars, premolars and primary molars and for glass ionomer cements. Overall, there remains a need for further trials of high quality, particularly in child populations with a low and a high caries risk, respectively. PMID:14960003

  18. Bonding Agents in Pit and Fissure Sealants: A Review

    PubMed Central

    Das, Usha Mohan; G, Suma

    2009-01-01

    Dental adhesive systems used for bonding dental resins to enamel and dentin have evolved through several "generations," with changes in chemistry, mechanism, number of bottles, application technique, and clinical effectiveness. The trend in the latest generation of dental bonding systems is to reduce the number of components and clinical placement steps. The introduction of i bond, a single-bottle dental adhesive system, is the latest of the new generation materials, and combines etchant, adhesive, and desensitizer in one component. This paper describes different dentin bonding agents, its evolution, mechanism of action and different commercially available dentin bonding agents and their role in the retention of pit and fissure sealant. PMID:25206115

  19. Sylvian fissure epidermoid cyst presenting with intention tremor

    PubMed Central

    Shah, Abhidha; Makkiyah, Feda; Goel, Atul

    2016-01-01

    Epidermoid tumors are benign tumors which contain keratin, cellular debris, and cholesterol, and are lined with stratified squamous epithelium. They grow in discreet silence sustained over a multitude of years. The tumors most commonly present with headache and seizures. We report the case of a 24-year-old male with a large sylvian fissure epidermoid tumor who presented with intention tremor. The patient was operated, and a near-total excision of the tumor was performed with a resolution of the tremor. PMID:27057232

  20. Fluoride release and uptake abilities of different fissure sealants

    PubMed Central

    Andenna, Gianluigi; Ceci, Matteo; Beltrami, Riccardo; Colombo, Marco; Cucca, Lucia

    2016-01-01

    Background The long-term capability of resin sealants and glass ionomer cements to release fluoride is associated to a reduction in pit and fissure caries. The regular use of fluoride varnishes/toothpastes can result in the absorption of fluoride into the sealant. The objective of the present study was to assess the fluoride release/uptake capacities of different fissure sealants. Material and Methods Three different fissure sealants (Fuji Triage/GC, Fissurit FX/Voco and Grandio Seal/Voco) were examined. Ten discs of each material were prepared. Each disc was incubated with distilled water and then the solution analyzed for diluted for fluoride concentration, using a combination of fluoride electrode (OrionGP 1 S/N 13824, Orion Research Inc, Boston, MA, USA) connected to an expandable ion analyzer (Orion 720A, Orion Research Inc, Boston, MA, USA). Standard curves between 1 and 100 ppm F- were used to calibrate the electrode. Cumulative fluoride release was measured on days 1, 2, 3, 5, 7, 21, 35 and 49, then two different fluoride varnishes/pastes (Profluorid Varnish/Voco, MI Paste Plus/GC), were applied to the sealants tested, and fluoride release (after reuptake) was measured on days 56, 70 and 84. Results Kruskal Wallis test confirmed significant differences in fluoride release between Fuji Triage/GC and Fissurit FX/Voco and Grandio Seal/Voco from day 1 (P < 0.001). The application of fluoride varnish Profluorid Varnish enhanced the fluoride release for all sealants (P < 0.05). MI Paste Plus enhanced the fluoride release for all sealants except for Fuji Triage/GC (P > 0.05). Conclusions The GIC-based sealant (Fuji Triage/GC) released significantly more fluoride than the resin sealants tested. The exposure to the fluoridated varnish (Profluorid Varnish) significantly recharged the sealants tested more than the CPP-ACPF toothpaste (MI Paste Plus). Key words:Fissure sealants, fluoride release, fluoride uptake, glass ionomer cements. PMID:27398179

  1. 40 CFR 65.62 - Process vent group determination.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ..., or Group 2B) for each process vent. Group 1 process vents require control, and Group 2A and 2B... 40 Protection of Environment 15 2011-07-01 2011-07-01 false Process vent group determination. 65... (CONTINUED) CONSOLIDATED FEDERAL AIR RULE Process Vents § 65.62 Process vent group determination. (a)...

  2. 40 CFR 65.62 - Process vent group determination.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ..., or Group 2B) for each process vent. Group 1 process vents require control, and Group 2A and 2B... 40 Protection of Environment 16 2012-07-01 2012-07-01 false Process vent group determination. 65... (CONTINUED) CONSOLIDATED FEDERAL AIR RULE Process Vents § 65.62 Process vent group determination. (a)...

  3. 40 CFR 65.62 - Process vent group determination.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ..., or Group 2B) for each process vent. Group 1 process vents require control, and Group 2A and 2B... 40 Protection of Environment 15 2010-07-01 2010-07-01 false Process vent group determination. 65... (CONTINUED) CONSOLIDATED FEDERAL AIR RULE Process Vents § 65.62 Process vent group determination. (a)...

  4. 40 CFR 65.62 - Process vent group determination.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ..., or Group 2B) for each process vent. Group 1 process vents require control, and Group 2A and 2B... 40 Protection of Environment 16 2013-07-01 2013-07-01 false Process vent group determination. 65... (CONTINUED) CONSOLIDATED FEDERAL AIR RULE Process Vents § 65.62 Process vent group determination. (a)...

  5. Fissure sealants: Knowledge and practice of Yemeni dental practitioners

    PubMed Central

    Al-Maweri, Sadeq Ali; Al-Jamaei, Aisha Ahmed; Halboub, Esam Saleh; Al-Soneidar, Walid Ahmed; Tarakji, Bassel; Alsalhani, Anas

    2016-01-01

    Objectives This study was conducted to evaluate Yemeni dental practitioners' knowledge and practices concerning fissure sealants. Materials and Methods: A modified questionnaire consisted of 25-items was distributed to 500 dentists working in Sana'a City. Descriptive statistics and Chi-square/Fisher's exact tests were used for statistical analyses. Results: The response rate was 74%. Most of the respondents were male (61.3%), general practitioners (84.2%), and had <5 years of clinical experience (48.3%). The respondents showed a reasonable level of knowledge about sealants, with the majority (88%) believed that there is strong scientific evidence about fissure sealants effectiveness and around 90% showed a good understanding of sealant placement instructions. On the other hand, respondents showed insufficient knowledge about sealants clinical practice. Conclusion: Although a high proportion of dental practitioners showed adequate knowledge about dental sealant, following guidelines and standardized procedures in clinical practice is lacking. These emphasize the need for regular continuing education courses for dental professional. PMID:27095903

  6. Mapping radiating graben-fissure systems and pit crater chains on Venus

    NASA Astrophysics Data System (ADS)

    Davey, Sarah

    This study has mapped two types of extensional tectono-magmatic structures including radiating graben-fissure systems (RGFS) in the Idunn Mons and Mielikki Mons study areas, and pit crater chains in Idunn Mons, Themis Regio, Ulfrun Regio, and Ganiki Planitia on Venus. The areas selected to map RGFS host high emissivity anomalies focused on a single volcano and are proposed to reflect younger lava flows which might have occurred as recently as 250 ka. A relative chronology of RGFS is determined using cross-cutting relationships between interacting systems and surface geology. The Idunn Mons high emissivity anomaly is host to the youngest magmatic and volcanic activity, while the Mielikki Mons high emissivity anomaly is not the youngest. Hierarchical clusters of pit crater chains are predominantly focused on RGFS and coronae. It is hypothesized that hierarchical clustering is due to a lithology related variable as lithology may dictate how tensile stress is expressed.

  7. Mineralization of Alvinella polychaete tubes at hydrothermal vents

    PubMed Central

    Georgieva, M N; Little, C T S; Ball, A D; Glover, A G

    2015-01-01

    Alvinellid polychaete worms form multilayered organic tubes in the hottest and most rapidly growing areas of deep-sea hydrothermal vent chimneys. Over short periods of time, these tubes can become entirely mineralized within this environment. Documenting the nature of this process in terms of the stages of mineralization, as well as the mineral textures and end products that result, is essential for our understanding of the fossilization of polychaetes at hydrothermal vents. Here, we report in detail the full mineralization of Alvinella spp. tubes collected from the East Pacific Rise, determined through the use of a wide range of imaging and analytical techniques. We propose a new model for tube mineralization, whereby mineralization begins as templating of tube layer and sublayer surfaces and results in fully mineralized tubes comprised of multiple concentric, colloform, pyrite bands. Silica appeared to preserve organic tube layers in some samples. Fine-scale features such as protein fibres, extracellular polymeric substances and two types of filamentous microbial colonies were also found to be well preserved within a subset of the tubes. The fully mineralized Alvinella spp. tubes do not closely resemble known ancient hydrothermal vent tube fossils, corroborating molecular evidence suggesting that the alvinellids are a relatively recent polychaete lineage. We also compare pyrite and silica preservation of organic tissues within hydrothermal vents to soft tissue preservation in sediments and hot springs. PMID:25556400

  8. Mineralization of Alvinella polychaete tubes at hydrothermal vents.

    PubMed

    Georgieva, M N; Little, C T S; Ball, A D; Glover, A G

    2015-03-01

    Alvinellid polychaete worms form multilayered organic tubes in the hottest and most rapidly growing areas of deep-sea hydrothermal vent chimneys. Over short periods of time, these tubes can become entirely mineralized within this environment. Documenting the nature of this process in terms of the stages of mineralization, as well as the mineral textures and end products that result, is essential for our understanding of the fossilization of polychaetes at hydrothermal vents. Here, we report in detail the full mineralization of Alvinella spp. tubes collected from the East Pacific Rise, determined through the use of a wide range of imaging and analytical techniques. We propose a new model for tube mineralization, whereby mineralization begins as templating of tube layer and sublayer surfaces and results in fully mineralized tubes comprised of multiple concentric, colloform, pyrite bands. Silica appeared to preserve organic tube layers in some samples. Fine-scale features such as protein fibres, extracellular polymeric substances and two types of filamentous microbial colonies were also found to be well preserved within a subset of the tubes. The fully mineralized Alvinella spp. tubes do not closely resemble known ancient hydrothermal vent tube fossils, corroborating molecular evidence suggesting that the alvinellids are a relatively recent polychaete lineage. We also compare pyrite and silica preservation of organic tissues within hydrothermal vents to soft tissue preservation in sediments and hot springs. PMID:25556400

  9. Explosive Volcanic Eruptions from Linear Vents on Earth, Venus and Mars: Comparisons with Circular Vent Eruptions

    NASA Technical Reports Server (NTRS)

    Glaze, Lori S.; Baloga, Stephen M.; Wimert, Jesse

    2010-01-01

    Conditions required to support buoyant convective plumes are investigated for explosive volcanic eruptions from circular and linear vents on Earth, Venus, and Mars. Vent geometry (linear versus circular) plays a significant role in the ability of an explosive eruption to sustain a buoyant plume. On Earth, linear and circular vent eruptions are both capable of driving buoyant plumes to equivalent maximum rise heights, however, linear vent plumes are more sensitive to vent size. For analogous mass eruption rates, linear vent plumes surpass circular vent plumes in entrainment efficiency approximately when L(sub o) > 3r(sub o) owing to the larger entrainment area relative to the control volume. Relative to circular vents, linear vents on Venus favor column collapse and the formation of pyroclastic flows because the range of conditions required to establish and sustain buoyancy is narrow. When buoyancy can be sustained, however, maximum plume heights exceed those from circular vents. For current atmospheric conditions on Mars, linear vent eruptions are capable of injecting volcanic material slightly higher than analogous circular vent eruptions. However, both geometries are more likely to produce pyroclastic fountains, as opposed to convective plumes, owing to the low density atmosphere. Due to the atmospheric density profile and water content on Earth, explosive eruptions enjoy favorable conditions for producing sustained buoyant columns, while pyroclastic flows would be relatively more prevalent on Venus and Mars. These results have implications for the injection and dispersal of particulates into the planetary atmosphere and the ability to interpret the geologic record of planetary volcanism.

  10. Fracture mechanical behavior of red sandstone containing a single fissure and two parallel fissures after exposure to different high temperature treatments

    NASA Astrophysics Data System (ADS)

    Yang, Sheng-Qi; Jing, Hong-Wen; Huang, Yan-Hua; Ranjith, P. G.; Jiao, Yu-Yong

    2014-12-01

    A detailed understanding of the brittle deformation behavior of sandstone containing pre-existing flaws at elevated temperatures is a key concern in underground engineering. In this research, uniaxial compression tests were performed to evaluate the effect of high temperature treatments (300, 600 or 900 °C) on the strength, deformability and fracture coalescence behavior of a sandstone containing either a single fissure or two parallel fissures. All experiments focused on rectangular prismatic (80 × 160 × 30 mm) specimens of red sandstone. Constant strain rate experiments were performed on either: (1) specimens that contained a single 2 mm-wide fissure or (2) specimens that contained two 2 mm-wide parallel fissures. The specimens containing either one or two fissures were either left at room temperature (i.e., no heat treatment), or heat treated to 300, 600 or 900 °C prior to experimentation. The results demonstrated that, in all cases, the strength and stiffness of red sandstone was increased at 300 °C, before decreasing up to our maximum temperature of 900 °C. However, the peak strain at failure always showed an increase when the temperature was increased. The crack initiation, propagation and coalescence process were monitored during the deformation using both photographic monitoring and acoustic emission (AE) monitoring techniques. The monitoring results showed that the cracking process depended on both the fissure geometry and the heat treatment temperature. The potential mechanisms causing the differences in the mechanical behavior observed with increasing temperature are discussed, as is the influence of the single fissure and the two parallel fissures on the crack evolution process. These results are important and valuable to understand the fracture mechanism of rock engineering in deep underground mining excavations and nuclear waste depositories.

  11. First Active Hydrothermal Vent Fields Discovered at the Equatorial Southern East Pacific Rise

    NASA Astrophysics Data System (ADS)

    Tao, C.; Lin, J.; Wu, G.; German, C. R.; Yoerger, D. R.; Chen, Y. J.; Guo, S.; Zeng, Z.; Han, X.; Zhou, N.; Li, J.; Xia, S.; Wang, H.; Ding, T.; Gao, S.; Qian, X.; Cui, R.; Zhou, J.; Ye, D.; Zhang8, Y.; Zhang, D.; Li, L.; Zhang, X.; Li, Y.; Wu, X.; Li, S.; He, Y.; Huang, W.; Wang, Y.; Wang, T.; Li, X.; Wang, K.; Gai, Y.; Science Party, D.; Baker, E. T.; Nakamura14, K.

    2008-12-01

    The third leg of the 2008 Chinese DY115-20 expedition on board R/V Dayangyihao has successfully discovered, for the first time, active hydrothermal vent fields on the fast-spreading Southern East Pacific Rise (SEPR) near the equator. This expedition follows the work of a 2005 expedition by R/V Dayangyihao, during which water column turbidity anomalies were measured in the region. The newly discovered vent fields are located along a 22-km-long ridge segment of the SEPR at 102.655°W/2.22°S, 102.646°W/2.152°S, 102.619°W/2.078°S, and 102.62°W/2.02°S, respectively, as well as on an off-axial volcano near 102.456°W/1.369°S. A significant portion of the activity appears to be concentrated along the edges of a seafloor fissure system. Furthermore, water column turbidity anomalies were observed over off-axis volcanoes near 102.827°W/2.084°S and 102.58°W/2.019°S. Video footage of the vent fields and water column turbidity, temperature, and methane anomalies were recorded by a deep-towed integrated system consisting of video, still camera, CTD, and ADCP, and MAPR and METS sensors. Two active hydrothermal fields at 2.217°S and 2.023°S were then extensively photographed and surveyed using the autonomous underwater vehicle ABE of the Woods Hole Oceanographic Institution (WHOI). Four samples of hydrothermal chimneys were successfully obtained by a TV-guided grab in three locations, showing evidence of high-temperature hydrothermal venting.

  12. Holocene intracontinental deformation of the northern North China Plain: Evidence of tectonic ground fissures

    NASA Astrophysics Data System (ADS)

    Xu, Liqing; Li, Sanzhong; Cao, Xianzhi; Somerville, I. D.; Suo, Yanhui; Liu, Xin; Dai, Liming; Zhao, Shujuan; Guo, Lingli; Wang, Pengcheng; Cao, Huahua

    2016-04-01

    Following the collecting and analyzing of field data on the geometry and kinematics characteristics of ground fissures in the northern North China Plain (NNCP), this paper shows that en échelon ground fissures or tectonic ground fissures with a length of several meters to tens of kilometers extending along active faults are possibly controlled by underlying active faults. There are two groups of tectonic ground fissures developed in the NNCP. One group consists of ENE-trending "right-stepping" ground fissures, some of which have a component of sinistral motion. The other group is NNE-trending "left-stepping" ground fissures with dextral motion. A large amount of data from trenches, boreholes and seismic exploration reflect that they are active-faulting-related. The NNW-trending regional extensional stress field and the reactivation of pre-existing faults are the major factors controlling ground fissures. Data from the Quaternary sedimentary records, deep incised valleys, the distribution of earthquakes and ground fissures, and our field work show that the Holocene intracontinental deformation of the NNCP is characterized by intense faulting and northwestward tilting, which may be related to a NNW-SSE-oriented tensional stress field in the shallow crust and asthenospheric upwelling in the mantle.

  13. Response to early generation selection for resistance to rice kernel fissuring

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The value of milled rice (Oryza sativa L.) depends on the percent whole versus broken kernels after milling. Kernel fissures caused by pre- or post-harvest stresses are the leading cause of breakage upon milling. ‘Cypress’ is known to be more fissure resistant (FR) than most cultivars, but breeding ...

  14. Early screening of recombinant inbred lines for fissure resistance in non-semidwarf rice

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Rice (Oryza sativa L.) kernel fissuring poses a major problem for both rice farmers and millers. It results in the decreased value of milled rice because of the increase in the percentage of broken kernels associated with fissuring. This study employs the use of fine mapping to increase the genetic ...

  15. 21 CFR 872.3765 - Pit and fissure sealant and conditioner.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Pit and fissure sealant and conditioner. 872.3765 Section 872.3765 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES DENTAL DEVICES Prosthetic Devices § 872.3765 Pit and fissure sealant...

  16. 21 CFR 872.3765 - Pit and fissure sealant and conditioner.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Pit and fissure sealant and conditioner. 872.3765 Section 872.3765 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES DENTAL DEVICES Prosthetic Devices § 872.3765 Pit and fissure sealant...

  17. 21 CFR 872.3765 - Pit and fissure sealant and conditioner.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Pit and fissure sealant and conditioner. 872.3765 Section 872.3765 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES DENTAL DEVICES Prosthetic Devices § 872.3765 Pit and fissure sealant...

  18. 21 CFR 872.3765 - Pit and fissure sealant and conditioner.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Pit and fissure sealant and conditioner. 872.3765 Section 872.3765 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES DENTAL DEVICES Prosthetic Devices § 872.3765 Pit and fissure sealant...

  19. Preserving rice quality: fine mapping and introgressing a fissure resistance locus

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Rice (Oryza sativa L.) kernel fissuring is a major concern of both rice producers and millers. Fissures are small cracks in the rice kernels that increase the percentage of breakage among the kernels when they are transported and milled, which decreases the value of processed rice. This study employ...

  20. 46 CFR 151.15-5 - Venting.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ...) Pressure-vacuum venting. A normally closed venting system fitted with a device to automatically limit the pressure or vacuum in the tank to design limits. Pressure-vacuum relief valves shall comply with the... devices in accordance with the requirements of § 54.15-13 of this chapter. (2) When a...

  1. A bestiary of ordinary vent activities at Stromboli (and what it tells us about vent conditions)

    NASA Astrophysics Data System (ADS)

    Gaudin, Damien; Taddeucci, Jacopo; Scarlato, Piergiorgio

    2015-04-01

    Normal active degassing at Stromboli (Aeolian Islands, Italy) is traditionally divided in two classes. Puffing correspond to the frequent (~1 Hz) release of small gas pockets (0.5 - 1 m of diameter) at low exit velocities (5 - 15 m/s). Whereas, Strombolian explosions occur at a frequency of 1 - 10 per hour, and are characterized the ejection of bombs and/or ash at high velocities (50 - 400 m/s). In order to get a broader overview of two types of degassing, we used a thermal high speed FLIR SC655 camera to monitor the temperature anomalies generated by the expelled gas, ash, and/or bombs. The enhanced time and spatial resolutions of the camera (200 frames per second, 15 cm wide pixels) enables to use numerical algorithms to distinguish and characterize individual ejection events. In particular, for each explosion and puff, we compute the temperature, the volume, the exit point and the rise velocities of the expelled material. These values, as well as the frequency of the release events, are used to portray a total of 12 vent activities, observed during three field campaigns in 2012, 2013 and 2014. Sustained puffing was visible on 7 cases, with an intensity ranging on at least two orders of magnitude. Although the released gas volume is sometimes highly variable, on some cases, constant sized puffs allows to define a typical discharge frequency ranging between 0.4 and 1.5 Hz. Regular Strombolian explosions, with various duration, intensity and ash contents, are reported in 6 cases, 2 of them simultaneously presenting a puffing activity. In some cases, we noticed modifications of the vent activity just before the explosions. These precursors, usually lasting about 1 second but occasionally reaching 10 seconds, can be sorted into 1) increase of the puffing activity ; 2) emission of gas plumes ; 3) inflation of the visible vent surface. Finally, one vent activity was hybrid between puffing and Strombolian explosions, with frequent explosions (1 Hz) ejecting numerous

  2. Groundwater-Mining-Induced Subsidence and Earth Fissures in Cedar Valley, Southwestern Utah

    NASA Astrophysics Data System (ADS)

    Knudsen, T. R.; Inkenbrandt, P.; Lund, W. R.; Lowe, M.; Bowman, S. D.

    2014-12-01

    Groundwater pumping in excess of recharge (groundwater mining) has lowered the potentiometric surface in Cedar Valley, southwestern Utah, by as much as 114 feet since 1939. Lowering the potentiometric surface (head decline) has caused permanent compaction of fine-grained sediments of the Cedar Valley aquifer. Recently acquired interferometric synthetic aperture radar (InSAR) imagery shows that land subsidence is occurring over an ~100 square-mile area, including two pronounced subsidence bowls in the northeastern (Enoch graben) and southwestern (Quichapa Lake area) parts of the valley. A lack of accurate historical benchmark elevation data over much of the valley prevents detailed long-term quantification of subsidence. In response to the land subsidence, earth fissures have formed along the margins of the Enoch graben and north and west of Quichapa Lake. Our initial inventory of Cedar Valley fissures, which relied on aerial-photography analysis, identified 3.9 miles of fissures in 2009. With newly acquired light detection and ranging (LiDAR) coverage in 2011, we more than doubled the total length of mapped fissures to 8.3 miles. Fissures on the west side of the Enoch graben exhibit ongoing vertical surface displacement with rates as high as 1.7 inches/year. The largest Enoch-graben-west fissure has displaced street surfaces, curb and gutter, and sidewalks, and has reversed the flow direction of a sewer line in a partially developed subdivision. Several Cedar Valley fissures are closely associated with, and in some places coincident with, mapped Quaternary faults. While the majority of Cedar Valley fissures are mapped in agricultural areas, continued groundwater mining and resultant subsidence will likely cause existing fissures to lengthen and new fissures to form that may eventually impact other developed areas of the valley.

  3. Filtered venting considerations in the United States

    SciTech Connect

    Dallman, R.J.; Hulman, L.G.; Kudrick, J.

    1988-01-01

    The capability to vent with or without attenuation of fission products exists at some US facilities. In addition, two utilities have proposed enhanced capabilities, and generic enhancements are being considered under a regulatory evaluation of severe accident vulnerabilities at all US commercial reactors. The paper 1) summarizes the history of filtered venting in the US including significant past and proposed related research; 2) summarizes an assessment of the positive and negative safety aspects of venting for a class of 24 US reactors (BWR Mark I), and 3) discusses the regulatory assessments being made of filtered venting as a severe accident management strategy, including potential attributes of both accident prevention and mitigation associated with venting. Lastly, based on a review of available literature on European initiatives, questions are raised; answers to which would significantly help US evaluations. 10 refs., 2 tabs.

  4. Low Gravity venting of Refrigerant 11

    NASA Technical Reports Server (NTRS)

    Labus, T. L.; Aydelott, J. C.; Lacovic, R. F.

    1972-01-01

    An experimental investigation was conducted in a five-second zero gravity facility to examine the effects of venting initially saturated Refrigerant 11 from a cylindrical container (15-cm diameter) under reduced gravitational conditions. The system Bond numbers studied were 0 (weightlessness), 9 and 63; the liquid exhibited a nearly zero-degree contact angle on the container surface. During the venting process, both liquid-vapor interface and liquid bulk vaporization occurred. The temperature of the liquid in the immediate vicinity of the liquid-vapor interface was found to decrease during venting, while the liquid bulk temperature remained constant. Qualitative observations of the effects of system acceleration, vent rate, and vapor volume presented. Quantitative information concerning the ullage pressure decay during low gravity venting is also included.

  5. Turbulent atmospheric plumes above line sources with an application to volcanic fissure eruptions on the terrestrial planets

    NASA Technical Reports Server (NTRS)

    Stothers, Richard B.

    1989-01-01

    The theory of turbulent plumes maintained above steady line sources of buoyancy is worked out in detail within the limitations of Taylor's entrainment assumption. It is applied to the structure of a pure plume injected into a stably stratified atmosphere. Volcanic basalt eruptions that develop from long, narrow vents create line source plumes, which rise well above the magmatic fire fountains playing near the ground level. The eruption of Laki in 1783 may provide an example of this style of eruption. Flood basalts are more ancient examples. Evidence of enormous fissure eruptions that occurred in the past on Mars and Venus also exists. Owing to the different properties of the atmospheres on these two planets from those on the earth, heights of line source plumes are expected to vary in the ratios 1:6:0.6 (earth:Mars:Venus). It is very unlikely that the observed increase of sulfur dioxide above the Venusian cloud deck in 1978 could have been due to a line source volcanic eruption, even if it had been a flood basalt eruption.

  6. Exploring rock fissures: does a specialized root morphology explain endemism on granite outcrops?

    PubMed Central

    Poot, Pieter; Hopper, Stephen D.; van Diggelen, Josepha M.H.

    2012-01-01

    Background and Aims Worldwide, many plant species are confined to open, shallow-soil, rocky habitats. Although several hypotheses have been proposed to explain this habitat specificity, none has been convincing. We suggest that the high level of endemism on shallow soils is related to the edaphic specialization needed to survive in these often extremely drought-prone habitats. Previous research has shown that species endemic to ironstone communities in SW Australia have a specialized root morphology that enhances their chance to access fissures in the underlying rock. Here we test the generality of these findings for species that are confined to a shallow-soil habitat that is of much greater global significance: granite outcrops. Methods We compared temporal and spatial root growth and allocation of three endemic woody perennials of SW Australian granite outcrop communities with those of congeners occurring on nearby deeper soils. Seedlings of all species were grown in 1·2 m long custom-made containers with a transparent bottom that allowed monitoring of root growth over time. Key Results The granite outcrop endemics mostly differed in a predictable way from their congeners from deeper soils. They generally invested a larger portion of their biomass in roots, distributed their roots faster and more evenly over the container and had a lower specific root length. In different species pairs the outcrop endemics achieved their apparent advantage by a different combination of the aforementioned traits. Conclusions Our results are consistent with earlier work, indicating that species restricted to different types of drought-prone shallow-soil communities have undergone similar selection pressures. Although adaptive in their own habitat in terms of obtaining access to fissures in the underlying rock, these root system traits are likely to be maladaptive in deeper soil habitats. Therefore, our results may provide an explanation for the narrow endemism of many shallow

  7. Evidence not practised: the underutilisation of preventive fissure sealants.

    PubMed

    Bonetti, D L

    2014-04-01

    International and UK professional organisations, Cochrane systematic reviews, and international and UK guidance documents all support the application of preventive fissure sealants (PFSs) as an effective treatment for reducing caries. However, PFSs are well known to be underutilised in primary care. This paper collates data from PFS-relevant studies in Scotland, which has a large population of children at caries risk, to identify the beliefs and factors dentists perceive as influencing their decision not to provide this treatment. This information provides a platform to suggest how to increase the application of PFSs in this region (a standardised audit incorporating evidence-based behaviour change techniques, supplemental guidance on how to implement gold-standard recommendations in practice, training). This may also be relevant outside of Scotland, as well as to the implementation of other evidence-based behaviours in practice. PMID:24722094

  8. Oil heat venting technology residential heating systems

    SciTech Connect

    Krajewski, R.F.; Celebi, Y.; Strasser, J.

    1991-05-01

    Tests were conducted on two oil-fired space heating appliances (a boiler and a furnace). Instead of using a chimney these appliances were configured to exhaust the combustion products through the side wall of the building (sidewall vent). The products of combustion were extracted mechanically (power-vent) from each of the appliances by using a fan (induced-draft fan) in the vent system. Measurements were made of the time required to clear the appliances of combustion products by running the vent fan after burner shutdown (postpurge). These measurements indicated that one minute of postpurge was sufficient to clear the combustion products. The required postpurge duration was longer when based upon controlling nozzle temperature rise after burner shutdown. This is due to heat soakback from the combustion chamber. In order to hold nozzle temperatures down, the required postpurge period was estimated to be about 3 minutes for the furnace and about 7 minutes for the boiler. Measurements were also made of the off-cycle energy losses due to postpurge duration. Furnaces are more severely impacted by postpurge losses than are boilers. In addition, tests were conducted on two boilers to determine the off-cycle losses due to an actual chimney system. A comparison of these results to those of the side-wall vent tests revealed the need for short postpurge durations to minimize losses. Calculations were made using the DOE test procedure and compared to the results of tests. Experimental results show that direct-vent systems perform as well as chimney-vent systems in terms of off-cycle losses. There is potential for an efficiency advantage for direct-vent over chimney-vent systems if postpurge requirements can be reduced. Initial efforts in developing a computer program for venting design and analysis are described. 7 refs., 39 figs., 4 tabs.

  9. Pleistocene microvertebrates from fissure-fillings in Thailand

    NASA Astrophysics Data System (ADS)

    Chaimanee, Yaowalak; Jaeger, Jean-Jacques; Suteethorn, Varavudh

    Microvertebrates (and among them specially, rodents) have contributed to the elaboration of precise biochronological time scales and to the reconstitution of Pleistocene paleoenvironments in several parts of the world (North America, Africa, Europe and Japan). They have been demonstrated to be highly sensitive to climatic changes since they are very sensitive to vegetation changes. Up to now, no data is available for Southeast Asia and very few information is available concerning the nature of climatic changes which affected that part of the tropical world during the Pleistocene. In the past few years, we have discovered several fissure fillings in Thailand yielding numerous remains of microvertebrates which have been extracted by dissolution in acetic acid solution. These deposits are the result of the feeding activity of predators, like owls or diurnal raptors, whose pellets are accumulated in caves or fissures. Eleven localities, located in Central (2), Eastern (1), Western (2) and Peninsular Thailand (6) have been investigated so far. Several rodent species, belonging to 9 genera of Murinae (rats and mice) and 9 genera of Sciuridae (squirrels) have been identified in these localities. The most important differences with the extant representatives often concern the size of the teeth of these fossil species. The meaning of these size differences is not yet clearly understood since they can be attributed either to significant time differences between localities (microevolution) or as the result of size variations related to climatic changes (clinical variations). More data will have to be collected to calibrate the temporal frame. Already, important modification of the geographic distribution of some species have been discovered which testify that during the Pleistocene, significative climatic changes have affected Southeast Asia. For example, Exilisciurus, a squirrel which is presently restricted to Borneo has been recognized in Peninsular Thailand. Also, Iomys

  10. Neotectonic activity at the Giant Gjallar Vent (Norwegian Sea) indicates a future phase of active fluid venting

    NASA Astrophysics Data System (ADS)

    Dumke, Ines; Berndt, Christian; Crutchley, Gareth; Couillard, Mélanie; Gay, Aurélien

    2013-04-01

    The Giant Gjallar Vent (GGV) is a hydrothermal vent complex that formed during the opening of the North Atlantic at about 55 Ma. Sill intrusions into Cretaceous organic-rich sediments led to the production and subsequent vigorous seafloor venting of methane. A later phase of fluid escape occurred in mid-Oligocene times. The GGV is characterised by two pipes of 440 m and 480 m in diameter that reach up to the Base Late Pliocene Unconformity (BLPU) between the Kai and Naust formations. The unconformity is strongly deformed over an area of c. 18,000 km² across the vent, with a positive relief of up to 38 m above the surrounding paleo-seafloor. The overlying sediments of the Naust Formation conformally drape this deformation, smoothing its relief to a maximum of 15 m at the modern seafloor. The sediment drape indicates present inactivity of the vent system, as does the absence of indicators of active fluid escape in the water column during RV METEOR cruise M87-2 in 2012. However, high-resolution 2D seismic and Parasound data from the same cruise, and exploration-type 3D seismic data acquired by Norsk Hydro, show several indications for recent to ongoing activity at the GGV. Beneath the BLPU, strong frequency attenuation and chaotic reflections indicate the presence of free gas. At the edges of the extent of chaotic reflections, subvertical faults cut the unconformity as well as horizons of the lower and middle Naust Formation, suggesting tectonic activity after deposition of these horizons. Neotectonic activity is further indicated by the extensive occurrence of shallow faults apparent in Parasound records in the immediate vicinity of the vent and up to 16 km away. Some of these faults reach the seafloor. The observed deformation and faults may be the result of fluids accumulating beneath the BLPU due to increased loading of the oozy Kai Formation by denser glacigenic Naust sediments. Because of the lower permeability of the Naust Formation, the unconformity acts as a

  11. Discrete element modeling on the crack evolution behavior of brittle sandstone containing three fissures under uniaxial compression

    NASA Astrophysics Data System (ADS)

    Yang, Sheng-Qi; Huang, Yan-Hua; Ranjith, P. G.; Jiao, Yu-Yong; Ji, Jian

    2015-12-01

    Based on experimental results of brittle, intact sandstone under uniaxial compression, the micro-parameters were firstly confirmed by adopting particle flow code (PFC^{2D}). Then, the validation of the simulated models were cross checked with the experimental results of brittle sandstone containing three parallel fissures under uniaxial compression. The simulated results agreed very well with the experimental results, including the peak strength, peak axial strain, and ultimate failure mode. Using the same micro-parameters, the numerical models containing a new geometry of three fissures are constructed to investigate the fissure angle on the fracture mechanical behavior of brittle sandstone under uniaxial compression. The strength and deformation parameters of brittle sandstone containing new three fissures are dependent to the fissure angle. With the increase of the fissure angle, the elastic modulus, the crack damage threshold, and the peak strength of brittle sandstone containing three fissures firstly increase and secondly decrease. But the peak axial strain is nonlinearly related to the fissure angle. In the entire process of deformation, the crack initiation and propagation behavior of brittle sandstone containing three fissures under uniaxial compression are investigated with respect to the fissure angle. Six different crack coalescence modes are identified for brittle sandstone containing three fissures under uniaxial compression. The influence of the fissure angle on the length of crack propagation and crack coalescence stress is evaluated. These investigated conclusions are very important for ensuring the stability and safety of rock engineering with intermittent structures.

  12. Modeling of earth fissures caused by land subsidence due to groundwater withdrawal

    NASA Astrophysics Data System (ADS)

    Panda, B. B.; Rucker, M. L.; Fergason, K. C.

    2015-11-01

    Land subsidence and earth fissures are phenomena related to groundwater withdrawal in a sedimentary basin. If the rock basement or basin lithology is irregular, both vertical and horizontal displacements can be induced due to differential settlement and tensile stresses appearing in the soil mass. If the differential settlement is of sufficient magnitude, earth fissuring can occur within tensile zones. The magnitudes of compaction and fissure geometry are closely related to the thickness and skeletal compressibility of fine-grained sediments within the aquifer system. Land subsidence and earth fissuring were modeled by employing a two-dimensional (2-D) coupled seepage and stress-strain finite element analysis. The basin bedrock geometry, lithological variation, measurements of surface displacements, and changes in hydraulic head were the critical input parameter for the subsidence modeling. Simulation results indicate that strain had exceeded the approximate threshold for fissure formation of 0.02 to 0.06 % in the area of the identified fissures. The numerical model was used to predict future subsidence and potential earth fissures for flood control structures within the metro Phoenix area.

  13. Infrasound from the 2007 fissure eruptions of Kīlauea Volcano, Hawai'i

    USGS Publications Warehouse

    Fee, D.; Garces, M.; Orr, T.; Poland, M.

    2011-01-01

    Varied acoustic signals were recorded at Kīlauea Volcano in mid-2007, coincident with dramatic changes in the volcano's activity. Prior to this time period, Pu'u 'Ō'ō crater produced near-continuous infrasonic tremor and was the primary source of degassing and lava effusion at Kīlauea. Collapse and draining of Pu'u 'Ō'ō crater in mid-June produced impulsive infrasonic signals and fluctuations in infrasonic tremor. Fissure eruptions on 19 June and 21 July were clearly located spatially and temporally using infrasound arrays. The 19 June eruption from a fissure approximately mid-way between Kīlauea's summit and Pu'u 'O'o produced infrasound for ~30 minutes-the only observed geophysical signal associated with the fissure opening. The infrasound signal from the 21 July eruption just east of Pu'u 'Ō'ō shows a clear azimuthal progression over time, indicative of fissure propagation over 12.9 hours. The total fissure propagation rate is relatively slow at 164 m/hr, although the fissure system ruptured discontinuously. Individual fissure rupture times are estimated using the acoustic data combined with visual observations.

  14. Preferential flow in fissured sediments in desert soils related to radioactive waste disposal

    SciTech Connect

    Scanlon, B.R.; Raney, J.A. . Bureau of Economic Geology)

    1992-01-01

    Unsaturated flow in fissured sediments in the Chihuahuan Desert of Texas was examined to determine if these features act as preferred pathways for water and solute transport. Fissures are surface features, or gulleys, that are underlain by fractures filled with sediment derived from surrounding areas. Hydraulic and chemical approaches were used to investigate unsaturated flow processes beneath and adjacent to fissures, and the results were compared with data from surrounding geomorphic systems such as arroyos, ephemeral streams, and interstreams. Typically, high water potentials in surficial sediments result from infiltration of recent precipitation. Below this surficial zone of high water potentials lies a zone of low water potentials that is much thinner beneath the fissure than in adjacent sediments or in sediments beneath ephemeral streams and interstreams. Maximum chloride concentrations in profiles in the near-surface fissured sediments were much lower than those measured in all other geomorphic systems. The corresponding moisture velocities in the fissured sediments ranged from 10 to 70 mm/yr. A tracer experiment demonstrated higher downward water and solute transport in the fracture fill beneath the fissure relative to adjacent sediments. Numerical simulations of the tracer experiment with the computer code TRACR3D reproduced the overall shape of the tracer plume. Sensitivity analyses demonstrated that the tracer plume is most sensitive to spatial variability in soil texture and the corresponding hydraulic parameters. The results from this study suggest that sediments in the fissured area act as preferred pathways in the shallow subsurface because surface runoff is concentrated in the fissures and because underlying fractures and cavities provide avenues for moisture and solute transport.

  15. VOC transport in vented drums containing simulated waste sludge

    SciTech Connect

    Liekhus, K.J.; Gresham, G.L.; Rae, C.; Connolly, M.J.

    1994-02-01

    A model is developed to estimate the volatile organic compound (VOC) concentration in the headspace of the innermost layer of confinement in a lab-scale vented waste drum containing simulated waste sludge. The VOC transport model estimates the concentration using the measured VOC concentration beneath the drum lid and model parameters defined or estimated from process knowledge of drum contents and waste drum configuration. Model parameters include the VOC diffusion characteristic across the filter vent, VOC diffusivity in air, size of opening in the drum liner lid, the type and number of layers of polymer bags surrounding the waste, VOC permeability across the polymer, and the permeable surface area of the polymer bags. Comparison of model and experimental results indicates that the model can accurately estimate VOC concentration in the headspace of the innermost layer of confinement. The model may be useful in estimating the VOC concentration in actual waste drums.

  16. Monitoring arrangement for vented nuclear fuel elements

    DOEpatents

    Campana, Robert J.

    1981-01-01

    In a nuclear fuel reactor core, fuel elements are arranged in a closely packed hexagonal configuration, each fuel element having diametrically opposed vents permitting 180.degree. rotation of the fuel elements to counteract bowing. A grid plate engages the fuel elements and forms passages for communicating sets of three, four or six individual vents with respective monitor lines in order to communicate vented radioactive gases from the fuel elements to suitable monitor means in a manner readily permitting detection of leakage in individual fuel elements.

  17. Hydrogen venting characteristics of commercial carbon-composite filters and applications to TRU waste

    SciTech Connect

    Callis, E.L.; Marshall, R.S.; Cappis, J.H.

    1997-04-01

    The generation of hydrogen (by radiolysis) and of other potentially flammable gases in radioactive wastes which are in contact with hydrogenous materials is a source of concern, both from transportation and on-site storage considerations. Because very little experimental data on the generation and accumulation of hydrogen was available in actual waste materials, work was initiated to experimentally determine factors affecting the concentration of hydrogen in the waste containers, such as the hydrogen generation rate, (G-values) and the rate of loss of hydrogen through packaging and commercial filter-vents, including a new design suitable for plastic bags. This report deals only with the venting aspect of the problem. Hydrogen venting characteristics of two types of commercial carbon-composite filter-vents, and two types of PVC bag closures (heat-sealed and twist-and-tape) were measured. Techniques and equipment were developed to permit measurement of the hydrogen concentration in various layers of actual transuranic (TRU) waste packages, both with and without filter-vents. A test barrel was assembled containing known configuration and amounts of TRU wastes. Measurements of the hydrogen in the headspace verified a hydrogen release model developed by Benchmark Environmental Corporation. These data were used to calculate revised wattage Emits for TRU waste packages incorporating the new bag filter-vent.

  18. Diverse styles of submarine venting on the ultraslow spreading Mid-Cayman Rise

    PubMed Central

    German, C. R.; Bowen, A.; Coleman, M. L.; Honig, D. L.; Huber, J. A.; Jakuba, M. V.; Kinsey, J. C.; Kurz, M. D.; Leroy, S.; McDermott, J. M.; de Lépinay, B. Mercier; Nakamura, K.; Seewald, J. S.; Smith, J. L.; Sylva, S. P.; Van Dover, C. L.; Whitcomb, L. L.; Yoerger, D. R.

    2010-01-01

    Thirty years after the first discovery of high-temperature submarine venting, the vast majority of the global mid-ocean ridge remains unexplored for hydrothermal activity. Of particular interest are the world’s ultraslow spreading ridges that were the last to be demonstrated to host high-temperature venting but may host systems particularly relevant to prebiotic chemistry and the origins of life. Here we report evidence for previously unknown, diverse, and very deep hydrothermal vents along the ∼110 km long, ultraslow spreading Mid-Cayman Rise (MCR). Our data indicate that the MCR hosts at least three discrete hydrothermal sites, each representing a different type of water-rock interaction, including both mafic and ultramafic systems and, at ∼5,000 m, the deepest known hydrothermal vent. Although submarine hydrothermal circulation, in which seawater percolates through and reacts with host lithologies, occurs on all mid-ocean ridges, the diversity of vent types identified here and their relative geographic isolation make the MCR unique in the oceans. These new sites offer prospects for an expanded range of vent-fluid compositions, varieties of abiotic organic chemical synthesis and extremophile microorganisms, and unparalleled faunal biodiversity—all in close proximity. PMID:20660317

  19. Diverse styles of submarine venting on the ultra-slow spreading Mid-Cayman Rise (Invited)

    NASA Astrophysics Data System (ADS)

    German, C. R.; Bowen, A.; Coleman, M. L.; Honig, D. L.; Huber, J. A.; Jakuba, M.; Kinsey, J. C.; Kurz, M. D.; Leroy, S.; McDermott, J.; Mercier de Lepinay, B. F.; Nakamura, K.; Seewald, J.; Smith, J.; Sylva, S.; van Dover, C. L.; Whitcomb, L. L.; Yoerger, D. R.

    2010-12-01

    Thirty years after the first discovery of high-temperature submarine venting, the vast majority of the global Mid Ocean Ridge remains unexplored for hydrothermal activity. Of particular interest are the world’s ultra-slow spreading ridges which were the last to be demonstrated to host high-temperature venting, but may host systems particularly relevant to pre-biotic chemistry and the origins of life. Here we report first evidence for diverse and very deep hydrothermal vents along the ~110 km long, ultra-slow spreading Mid-Cayman Rise collected using a combination of CTD-rosette operations and dives of the Hybrid Remotely Operated Vehicle (HROV) Nereus in 2009 followed by shore based work-up of samples for geochemical and microbiological analyses. Our data indicate that the Mid-Cayman Rise hosts at least three discrete hydrothermal sites, each representing a different type of water-rock interaction, including both mafic and ultra-mafic systems and, at ~5000 m, the deepest known hydrothermal vent. Although submarine hydrothermal circulation, in which seawater percolates through and reacts with host lithologies, occurs on all mid-ocean ridges, the diversity of vent-types identified here and their relative geographic isolation make the Mid-Cayman Rise unique in the oceans. These new sites offer prospects for: an expanded range of vent-fluid compositions; varieties of abiotic organic chemical synthesis and extremophile microorganisms; and unparalleled faunal biodiversity - all in close proximity.

  20. 24 CFR 3280.710 - Venting, ventilation and combustion air.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 24 Housing and Urban Development 5 2010-04-01 2010-04-01 false Venting, ventilation and combustion... Fuel Burning Systems § 3280.710 Venting, ventilation and combustion air. (a) The venting as required by... appliance listing and the appliance manufacturer's instructions. (b) Venting and combustion air...

  1. 24 CFR 3280.710 - Venting, ventilation and combustion air.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 24 Housing and Urban Development 5 2011-04-01 2011-04-01 false Venting, ventilation and combustion... Fuel Burning Systems § 3280.710 Venting, ventilation and combustion air. (a) The venting as required by... appliance listing and the appliance manufacturer's instructions. (b) Venting and combustion air...

  2. 40 CFR 65.143 - Closed vent systems.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 15 2011-07-01 2011-07-01 false Closed vent systems. 65.143 Section 65...) CONSOLIDATED FEDERAL AIR RULE Closed Vent Systems, Control Devices, and Routing to a Fuel Gas System or a Process § 65.143 Closed vent systems. (a) Closed vent system equipment and operating requirements....

  3. 46 CFR 153.362 - Venting system drain.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 5 2010-10-01 2010-10-01 false Venting system drain. 153.362 Section 153.362 Shipping... Systems § 153.362 Venting system drain. Unless a cargo vent system at every point is level or slopes back... system must have a drain valve at each low point (trap) in the vent line....

  4. 14 CFR 125.159 - Vent and drain lines.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 3 2010-01-01 2010-01-01 false Vent and drain lines. 125.159 Section 125... Requirements § 125.159 Vent and drain lines. All vent and drain lines, and their fittings, that are located in... Administrator finds that the rupture or breakage of any vent or drain line may result in a fire hazard....

  5. BIOREMEDIATED SOIL VENTING OF LIGHT HYDROCARBONS

    EPA Science Inventory

    The effectiveness and feasibility of bioremediated soil venting of light hydrocarbons in the unsaturated zone was investigated. Degradation mechanics were considered as a one dimensional balance of storage, linear sorption, vertical advection, and Michaelis-Menton kinetics. he re...

  6. External Tank GH2 Vent Arm

    NASA Technical Reports Server (NTRS)

    Reichle, G. E.; Glassburn, C. W.

    1985-01-01

    Because the venting of free hydrogen gas to the atmosphere presents an extremely hazardous situation, it was necessary to devise a means for safe, controlled venting of the shuttle external tank gaseous hydrogen during and after liquid hydrogen tank loading. Several design concepts that were considered initially were discarded as unfeasible because of vehicle weight restrictions, high cost, and because the proposed structure was itself deemed a hazard due to the vehicle's nonvertical launch trajectory. These design concepts are discussed. A design employing a support structure/access arm attached to the fixed service structure was finally selected. The various design problems resolved included vent arm disconnect/drop interference, minimizing refurbishment due to launch damage, disconnect reliability, vehicle movement tracking, minimizing vent line pressure drop, and the presence of other vehicle services at the same centralized supply area. Six launches have proven the system to be reliable, efficient, and of nearly zero refurbishment cost.

  7. Efficient Vent Unloading of Air Compressors

    NASA Technical Reports Server (NTRS)

    Muhonen, Alvin J.

    1987-01-01

    Method for unloading one-and two-stage reciprocating air compressors increases energy efficiency and inhibits deterioration of components. In new unloader configuration, compressor vented to atmosphere on downstream side. Method implemented expeditiously as modification of existing systems.

  8. VentDB: A Global Online Synthesis Database of Seafloor Hydrothermal Spring Geochemistry

    NASA Astrophysics Data System (ADS)

    Mottl, M. J.; Lehnert, K. A.; Johansson, A. K.; Hsu, L.

    2011-12-01

    Chemical data for seafloor hydrothermal springs are fundamental to the study of mid-ocean ridge and seafloor processes, ocean water chemistry, and global geochemical cycles, as well as vent ecosystems and the sub-seafloor biosphere. So far, these data have been accessible only in the scientific literature or in online data catalogs where they are widely dispersed in individual data tables, and are often insufficiently documented for re-use. We have developed VentDB as an online data system for geochemical data for hydrothermal springs that will facilitate access and analysis of these data. VentDB uses the concept and architecture of the popular PetDB database for seafloor igneous and metamorphic rock geochemistry (www.petdb.org) to provide easy and fast access to a global synthesis of seafloor hydrothermal spring geochemical data. The VentDB database contains concentrations of major and trace species, dissolved gases, and radiogenic and isotopic ratios for hydrothermal vents on the seafloor. Further chemical or physical properties of hydrothermal springs can be included in the future if desired. The database comprises both the calculated hydrothermal end-member solution compositions as estimated by extrapolation of the concentrations of individual chemical species to a Mg concentration of zero, and the raw data for hydrothermal solution samples as collected, where available. Data quality is documented by including information for the raw analytical data about the analytical method, precision, and reference material measurements, and quality control parameters for end-member compositions including the lowest Mg measured in any sample, the number of samples and correlation coefficient of the linear regression, and the charge balance for the extrapolated zero-Mg composition. The database also includes information about the sampled locations (geospatial coordinates, vent or vent field names, names of other physiographic features), temperature, flow and vent type

  9. Zero-gravity venting of three refrigerants

    NASA Technical Reports Server (NTRS)

    Labus, T. L.; Aydelott, J. C.; Amling, G. E.

    1974-01-01

    An experimental investigation of venting cylindrical containers partially filled with initially saturated liquids under zero-gravity conditions was conducted in the NASA Lewis Research Center 5-second zero-gravity facility. The effect of interfacial mass transfer on the ullage pressure response during venting was analytically determined, based on a conduction analysis applied to an infinitely planer (flat) liquid-vapor interface. This pressure response was compared with both the experimental results and an adiabatic decompression computation.

  10. Safe venting of ``red oil`` runaway reactions

    SciTech Connect

    Paddleford, D.F.; Fauske, H.K.

    1994-12-21

    Calorimetry testing of Tri-n-butyl phosphate (TBP) saturated with strong nitric acid was performed to determine the relationship between vent size and pressure buildup in the event of a runaway reaction. These experiments show that runaway can occur in an open system, but that even when runaway is induced in the TBP/HN0{sub 3} system, dangerous pressure buildup will be prevented with practical vent size.

  11. Vented coke oven door apparatus

    SciTech Connect

    Brown, H. B.; Gerding, C. C.

    1980-08-12

    A vented coke oven door includes a door frame having a vertical face surface carrying a plug assembly having a central vertical internal opening to conduct coke oven gas generated at the bottom of a coal charge in a coke oven chamber. The plug assembly includes a plurality of u-shaped refractory plug segments arranged in an end-to-end aligned relation with leg sections of each u-shaped segment extending horizontally into an abutting relation with the face surface of the door frame. Each leg section carries either an embedded hooked end or a t-shaped head of a threaded fastener which is supported by the door frame so that the leg sections are unrestrained against movement toward and away from each other in response to a thermal gradient across the wall thickness of the refractory plug segment. A backing plug plate is fitted into a recess in the leg sections of each plug segment to provide a closure wall to the u-shaped configuration of the segments and forms the vertical passageway for conducting coke oven gas. The backing plug plate has an exposed layer of cast refractory overlying a layer of insulation used to protect the door frame. A seal strip extends about the outer periphery of the door frame to prevent emission of coke oven gas from the coking chamber.

  12. The vent microbiome: patterns and drivers

    NASA Astrophysics Data System (ADS)

    Pachiadaki, M.

    2015-12-01

    Microbial processes within deep-sea hydrothermal vents affect the global biogeochemical cycles. Still, there are significant gaps in our understanding of the microbiology and the biogeochemistry of deep-sea hydrothermal systems. Vents differ in temperature, host rock composition and fluid chemistry; factors that are hypothesized to shape the distribution of the microbial communities, their metabolic capabilities and their activities. Using large-scale single cell genomics, we obtained insights into the genomic content of several linkages of a diffuse flow vent. The genomes show high metabolic versatility. Sulfur oxidation appears to be predominant but there is the potential of using a variety of e- donors and acceptors to obtain energy. To further assess the ecological importance of the vent auto- and heterotrophs, the global biogeography of the analyzed lineages will be investigated by fragment recruitment of metagenomes produced from the same site as well as other hydrothermal systems. Metatranscriptomic and metaproteomic data will be integrated to examine the expression of the predominant metabolic pathways and thus the main energy sources driving chemoautotrophic production. The comparative analysis of the key players and associated pathways among various vent sites that differ in physicochemical characteristics is anticipated to decipher the patterns and drivers of the global dispersion and the local diversification of the vent microbiome.

  13. Mechanical benefits of conservative restoration for dental fissure caries.

    PubMed

    Zhang, Zhongpu; Zheng, Keke; Li, Eric; Li, Wei; Li, Qing; Swain, Michael V

    2016-01-01

    The principle of minimal intervention dentistry (MID) is to limit removal of carious tooth tissue while maximizing its repair and survival potential. The objective of this study is to explore the fracture resistance of a permanent molar tooth with a fissure carious lesion along with three clinical restoration procedures, namely one traditional and two conservative approaches, based upon MID. The traditional restoration employs extensive surgical removal of enamel and dentine about the cavity to eliminate potential risk of further caries development, while conservative method #1 removes significantly less enamel and infected dentine, and conservative method #2 only restores the overhanging enamel above the cavity and leaves the infected and affected dentine as it was. An extended finite element method (XFEM) is adopted here to analyze the fracture behaviors of both two-dimensional (2D) and three-dimensional (3D) modeling of these four different scenarios. It was found that the two conservative methods exhibited better fracture resistance than the traditional restorative method. Although conservative method #2 has less fracture resistance than method #1, it had significantly superior fracture resistance compared to other restorations. More important, after cavity sealing it may potentially enhance the opportunity for remineralization and improved loading bearing capacity and fracture resistance. PMID:26298801

  14. Land subsidence and earth fissures due to groundwater withdrawal in the Southern Yangtse Delta, China

    NASA Astrophysics Data System (ADS)

    Zhang, Yun; Xue, Yu-Qun; Wu, Ji-Chun; Yu, Jun; Wei, Zi-Xin; Li, Qin-Fen

    2008-08-01

    Excessive extraction of groundwater has caused severe land subsidence and earth fissures in the Southern Yangtse Delta, China. Based on field data, the temporal and spatial distribution of land subsidence is investigated and the causes for earth fissures are analyzed. The areal distribution of the land subsidence is closely related to the cones of depression in the main exploited aquifers. The compaction of a hydrostratigraphic unit depends on its mechanical behavior, thickness, compressibility, and the piezometric level changing. The primary subsidence layers in Shanghai have been the first aquitard before 1990 and the third confined aquifer since then. But the second aquitard unit was the primary subsidence layer in Changzhou. Earth fissures, trending in several directions, occurred in the Husu tectonic zone. They were mainly caused by differential subsidence and horizontal displacement that resulted from tensile stress and shear stress in units. The majority of fissures in the study area are tensile.

  15. Use of CO2 laser in pit and fissure caries prevention: clinical evaluation

    NASA Astrophysics Data System (ADS)

    Brugnera, Aldo, Jr.; Rosso, Naomi; Duarte, Danilo; Guedes Pinto, Antonio C.; Genovese, Walter J.

    1997-05-01

    In this four-year follow up in vivo controlled study, 112 human permanent first molars, from children between the ages of 6 and 11 years old were used to investigate the viability of the CO2 laser in promoting carie-free occlusal surfaces in permanent molars, as an isolated form of treatment or associated with conventional fissure sealants. The findings suggest that occlusal caries prevention only by means of CO2 laser irradiation is not effective; that the utilization of photo-activated sealants, as well as its association with CO2 laser, applied over the occlusal fissures, are effective means of preventing occlusal caries and that the application of CO2 laser over occlusal fissures, prior to the application of a photo-activated fissure sealant, improves the retention of the sealant.

  16. 21 CFR 872.3765 - Pit and fissure sealant and conditioner.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... (CONTINUED) MEDICAL DEVICES DENTAL DEVICES Prosthetic Devices § 872.3765 Pit and fissure sealant and... depressions (faults in the enamel) in the biting surfaces of teeth to prevent cavities. (b)...

  17. Painless Ulcers and Fissures of Toes: Hereditary Sensory Neuropathy, Not Leprosy

    PubMed Central

    Rao, Angoori Gnaneshwar

    2016-01-01

    Hereditary sensory neuropathies (HSN) are rare genetically determined neuropathies. They often manifest as painless injuries in children. We present HSN in a 5-year-old boy who presented with recurrent fissuring and ulceration involving both great toes. PMID:26955138

  18. Geologic form and setting of a hydrothermal vent field at latitude 10/sup 0/56'N, East Pacific Rise: a detailed study using Angus and Alvin

    SciTech Connect

    McConachy, T.F.; Ballard, R.D.; Mottl, M.J.; Von Herzen, R.P.

    1986-04-01

    A hydrothermal vent field, here called the Feather Duster site, occurs on the eastern marginal high near the edge of a narrow (95-m) and shallow (15-20-m) axial graben, within an area dominated by sheet flows and collapse features. The sheet flows are intermediate in relative age between younger fluid-flow lavas on the floor of the axial graben and older pillow (constructional) lavas on the marginal highs. Hydrothermal activity occurs in two zones within a 65 by 45 m area. The main zone is located where a fissure system and sulfide-sulfate chimneys vent warm (9-47/sup 0/C) and hot (347/sup 0/C) hydrothermal fluids. Here, two mounds of massive sulfide totaling about 200 t are forming. One occurs at the base of a 3-m-high scarp which is the wall of a drained lava lake; the other is perched on top of the scarp. 19 references, 4 figures.

  19. Putative fissure-resistance QTLs mapped to chromosomes 1 and 8 based on allelic frequency differences observed between fissure-resistant and fissure-susceptible progeny from two segregating populations

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Whole rice kernels have two to three times more market value than broken, which means that any reduction in milling yield results in financial losses for both rice producers and millers. One of the primary causes of rice breakage during milling is fissuring of the rice before it even enters the mil...

  20. Explosion testing for the container venting system

    SciTech Connect

    Cashdollar, K.L.; Green, G.M.; Thomas, R.A.; Demiter, J.A.

    1993-09-30

    As part of the study of the hazards of inspecting nuclear waste stored at the Hanford Site, the US Department of Energy and Westinghouse Hanford Company have developed a container venting system to sample the gases that may be present in various metal drums and other containers. In support of this work, the US Bureau of Mines has studied the probability of ignition while drilling into drums and other containers that may contain flammable gas mixtures. The Westinghouse Hanford Company drilling procedure was simulated by tests conducted in the Bureau`s 8-liter chamber, using the same type of pneumatic drill that will be used at the Hanford Site. There were no ignitions of near-stoichiometric hydrogen-air or methane-air mixtures during the drilling tests. The temperatures of the drill bits and lids were measured by an infrared video camera during the drilling tests. These measured temperatures are significantly lower than the {approximately}500{degree}C autoignition temperature of uniformly heated hydrogen-air or the {approximately}600{degree}C autoignition temperature of uniformly heated methane-air. The temperatures are substantially lower than the 750{degree}C ignition temperature of hydrogen-air and 1,220{degree}C temperature of methane-air when heated by a 1-m-diameter wire.

  1. Fluorine mapping in sound and carious fissures of human teeth using PIGE

    NASA Astrophysics Data System (ADS)

    Yamamoto, H.; Nomachi, M.; Yasuda, K.; Iwami, Y.; Ebisu, S.; Sakai, T.; Fukuda, M.

    2005-04-01

    By using the PIGE technique at JAERI Takasaki, we measured fluorine (F) distribution in a micro area of occlusal fissures in the enamel of human teeth. The fissures were classified into three groups: Group I, no caries; Group II, incipient caries; Group III, advanced caries. The extracted teeth were embedded in epoxy resin and cut along the longitudinal axis through the fissures. The F concentration in the fissure at the cut surface was measured. A 1.7 MeV proton beam accelerated by the TIARA single-ended accelerator was delivered to a micro-beam apparatus. The beam spot size was about 1 μm with a beam current of about 100 pA. A nuclear reaction, 19F (p,αγ)16O, was used to measure the F concentration and gamma-rays from this reaction were detected with a 4″ NaI(Tl) detector. X-rays induced by proton were detected with a Ge detector to measure calcium concentration and the beam intensity was monitored with the X-ray yield from a copper foil for quantitative analysis. The obtained results were shown as two-dimensional mapping. In all specimens, an F concentration was observed around the fissure. The F concentration varied depending on the location of the fissure and decreased towards the inner part of the tooth. The maximum F concentration values in the measured area ranged from 3500-11700 ppm (mean = 6000 ppm) in Group I, 2400-10700 ppm (mean = 6300 ppm) in Group II, and 5200-16900 ppm (mean = 9300 ppm) in Group III. Although high F concentrations tended to be measured in the carious fissures, high values were also recognized in the sound fissures. More studies are necessary to clarify the relationship between F and carious lesions.

  2. Adaptive Management of Land Subsidence and Ground Fissuring in the Chino Groundwater Basin, California

    NASA Astrophysics Data System (ADS)

    Malone, A.; Rolfe, T.; Wildermuth, M.; Kavounas, P.

    2014-12-01

    The Chino Basin, located in southern California, is a large alluvial groundwater basin with storage in excess of five million acre-feet. The basin has a long history of groundwater development for various uses dating back to the early 1900s. As a result, piezometric heads declined basin-wide during the past century - in some areas by more than 200 feet. Declines of this magnitude typically cause irreversible aquifer-system compaction, which in turn results in subsidence at the ground surface. In portions of Chino Basin, land subsidence has been differential and accompanied by ground fissuring, which damaged existing infrastructure and poses concerns for new and existing development.Chino Basin Watermaster, the agency responsible for groundwater basin management, has recognized that land subsidence and ground fissuring should be minimized to the extent possible. At the same time, Watermaster is implementing aggressive groundwater-supply programs that include controlled overdraft and the possibility of causing head declines in areas prone to subsidence and fissuring. The groundwater-supply programs must also address the subsidence and fissuring phenomena.From 2001 to 2005, Watermaster conducted a technical investigation to characterize the extent, rate, and mechanisms of subsidence and fissuring. The investigation employed InSAR and ground-level surveying of benchmarks to monitor ground-surface deformation, and borehole extensometers and piezometric monitoring to establish the relationships between groundwater production, piezometric levels, and aquifer-system deformation. Based on the results of the investigation, Watermaster developed: (i) subsidence-management criteria for the areas experiencing acute subsidence and fissuring, and (ii) an adaptive management program to minimize the potential for future subsidence and fissuring across the entire Chino Basin. The science-based program includes ongoing monitoring, which now includes sophisticated fissure

  3. Comparative study of vent and seep macrofaunal communities in the Guaymas Basin

    NASA Astrophysics Data System (ADS)

    Portail, M.; Olu, K.; Escobar-Briones, E.; Caprais, J. C.; Menot, L.; Waeles, M.; Cruaud, P.; Sarradin, P. M.; Godfroy, A.; Sarrazin, J.

    2015-06-01

    Understanding the ecological processes and connectivity of chemosynthetic deep-sea ecosystems requires comparative studies. In the Guaymas Basin (Gulf of California, Mexico), the presence of seeps and vents in the absence of biogeographic barrier, comparable sedimentary settings and depths offers a unique opportunity to assess the role of ecosystem specific environmental conditions on macrofaunal communities. Six seep and four vent assemblages were studied, three of which were characterised by common major foundation taxa: vesicomyid bivalves, siboglinid tubeworms and microbial mats. Macrofaunal community structure at the family level showed that density, diversity and composition patterns were primarily shaped by seep and vent common abiotic factors including methane and hydrogen sulphide concentrations. The type of substratum and the heterogeneity provided by foundation species were identified as additional structuring factors and their roles were found to vary according to fluid regimes. Surprisingly, the presence of vent environmental specificities, with higher temperature, higher metal concentrations and lower pH was not significant in explaining community patterns. Moreover, Guaymas seep and vent shared an important number of common species suggesting frequent connections between the two ecosystems. Finally, this study provides further support for the hypothesis of continuity among deep-sea seep and vent ecosystems.

  4. Monitoring on Xi'an ground fissures deformation with TerraSAR-X data

    USGS Publications Warehouse

    Zhao, C.; Zhang, Q.; Zhu, W.; Lu, Zhiming

    2012-01-01

    Owing to the fine resolution of TerraSAR-X data provided since 2007, this paper applied 6 TerraSAR data (strip mode) during 3rd Dec. 2009 to 23rd Mar. 2010 to detect and monitor the active fissures over Xi'an region. Three themes have been designed for high precision detection and monitoring of Xi'an-Chang'an fissures, as small baseline subsets (SBAS) to test the atmospheric effects of differential interferograms pair stepwise, 2-pass differential interferogram with very short baseline perpendicular to generate the whole deformation map with 44 days interval, and finally, corner reflector (CR) technique was used to closely monitor the relative deformation time series between two CRs settled crossing two ground fissures. Results showed that TerraSAR data are a good choice for small-scale ground fissures detection and monitoring, while special considerations should be taken for their great temporal and baseline decorrelation. Secondly, ground fissures in Xi'an were mostly detected at the joint section of stable and deformable regions. Lastly, CR-InSAR had potential ability to monitor relative deformation crossing fissures with millimeter precision.

  5. Energy metabolism and cellular homeostasis trade-offs provide the basis for a new type of sensitivity to ocean acidification in a marine polychaete at a high-CO2 vent: adenylate and phosphagen energy pools versus carbonic anhydrase.

    PubMed

    Turner, Lucy M; Ricevuto, Elena; Massa-Gallucci, Alexia; Gambi, Maria-Cristina; Calosi, Piero

    2015-07-01

    Species distributions and ecology can often be explained by their physiological sensitivity to environmental conditions. Whilst we have a relatively good understanding of how these are shaped by temperature, for other emerging drivers, such as PCO2  we know relatively little. The marine polychaete Sabella spallanzanii increases its metabolic rate when exposed to high PCO2  conditions and remains absent from the CO2 vent of Ischia. To understand new possible pathways of sensitivity to CO2 in marine ectotherms, we examined the metabolic plasticity of S. spallanzanii exposed in situ to elevated PCO2  by measuring fundamental metabolite and carbonic anhydrase concentrations. We show that whilst this species can survive elevated PCO2  conditions in the short term, and exhibits an increase in energy metabolism, this is accompanied by a significant decrease in carbonic anhydrase concentration. These homeostatic changes are unlikely to be sustainable in the longer term, indicating S. spallanzanii may struggle with future high PCO2  conditions. PMID:25987731

  6. Fracturing and earthquake activity within the Prestahnúkur fissure swarm in the Western Volcanic Rift Zone of Iceland

    NASA Astrophysics Data System (ADS)

    Hjartardóttir, Ásta Rut; Hjaltadóttir, Sigurlaug; Einarsson, Páll; Vogfjörd, Kristín.; Muñoz-Cobo Belart, Joaquín.

    2015-12-01

    The Prestahnúkur fissure swarm is located within the ultraslowly spreading Western Volcanic Zone in Iceland. The fissure swarm is characterized by normal faults, open fractures, and evidence of subglacial fissure eruptions (tindars). In this study, fractures and faults within the Prestahnúkur fissure swarm were mapped in detail from aerial photographs to determine the extent and activity of the fissure swarm. Earthquakes during the last ~23 years were relocated to map the subsurface fault planes that they delineate. The Prestahnúkur fissure swarm is 40-80 km long and up to ~20 km wide. Most of the areas of the fissure swarm have been glacially eroded, although a part of it is covered by postglacial lava flows. The fissure swarm includes numerous faults with tens of meters vertical offset within the older glacially eroded part, whereas open fractures are found within postglacial lava flows. Comparison of relocated earthquakes and surface fractures indicates that some of the surface fractures have been activated at depth during the last ~23 years, although no dike intrusions have been ongoing. The existence of tindars nevertheless indicates that dike intrusions and rifting events do occur within the Prestahnúkur fissure swarm. The low-fracture density within postglacial lava flows and low density of postglacial eruptive fissures indicate that rifting episodes occur less often than in the faster spreading Northern Volcanic Zone.

  7. 14 CFR 29.975 - Fuel tank vents and carburetor vapor vents.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... top part of the expansion space so that venting is effective under normal flight conditions. In..., during— (i) Normal flight operation; (ii) Maximum rate of ascent and descent; and (iii) Refueling and... attitude or the level flight attitude, unless drainage is provided; (6) No vent or drainage provision...

  8. 14 CFR 29.975 - Fuel tank vents and carburetor vapor vents.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... top part of the expansion space so that venting is effective under normal flight conditions. In..., during— (i) Normal flight operation; (ii) Maximum rate of ascent and descent; and (iii) Refueling and... attitude or the level flight attitude, unless drainage is provided; (6) No vent or drainage provision...

  9. 14 CFR 25.975 - Fuel tank vents and carburetor vapor vents.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... top part of the expansion space so that venting is effective under any normal flight condition. In..., during— (i) Normal flight operation; (ii) Maximum rate of ascent and descent; and (iii) Refueling and... attitude or the level flight attitude, unless drainage is provided; and (6) No vent or drainage...

  10. 14 CFR 23.975 - Fuel tank vents and carburetor vapor vents.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 14 Aeronautics and Space 1 2013-01-01 2013-01-01 false Fuel tank vents and carburetor vapor vents. 23.975 Section 23.975 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION AIRCRAFT AIRWORTHINESS STANDARDS: NORMAL, UTILITY, ACROBATIC, AND COMMUTER CATEGORY AIRPLANES Powerplant Fuel System § 23.975 Fuel tank...

  11. 14 CFR 29.975 - Fuel tank vents and carburetor vapor vents.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... top part of the expansion space so that venting is effective under normal flight conditions. In..., during— (i) Normal flight operation; (ii) Maximum rate of ascent and descent; and (iii) Refueling and... attitude or the level flight attitude, unless drainage is provided; (6) No vent or drainage provision...

  12. 14 CFR 29.975 - Fuel tank vents and carburetor vapor vents.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... top part of the expansion space so that venting is effective under normal flight conditions. In..., during— (i) Normal flight operation; (ii) Maximum rate of ascent and descent; and (iii) Refueling and... attitude or the level flight attitude, unless drainage is provided; (6) No vent or drainage provision...

  13. 14 CFR 25.975 - Fuel tank vents and carburetor vapor vents.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... top part of the expansion space so that venting is effective under any normal flight condition. In..., during— (i) Normal flight operation; (ii) Maximum rate of ascent and descent; and (iii) Refueling and... attitude or the level flight attitude, unless drainage is provided; and (6) No vent or drainage...

  14. 14 CFR 25.975 - Fuel tank vents and carburetor vapor vents.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... top part of the expansion space so that venting is effective under any normal flight condition. In..., during— (i) Normal flight operation; (ii) Maximum rate of ascent and descent; and (iii) Refueling and... attitude or the level flight attitude, unless drainage is provided; and (6) No vent or drainage...

  15. 14 CFR 25.975 - Fuel tank vents and carburetor vapor vents.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... top part of the expansion space so that venting is effective under any normal flight condition. In..., during— (i) Normal flight operation; (ii) Maximum rate of ascent and descent; and (iii) Refueling and... attitude or the level flight attitude, unless drainage is provided; and (6) No vent or drainage...

  16. ANALYSIS OF VENTING OF A RESIN SLURRY

    SciTech Connect

    Laurinat, J.; Hensel, S.

    2012-03-27

    A resin slurry venting analysis was conducted to address safety issues associated with overpressurization of ion exchange columns used in the Purex process at the Savannah River Site (SRS). If flow to these columns were inadvertently interrupted, an exothermic runaway reaction could occur between the ion exchange resin and the nitric acid used in the feed stream. The nitric acid-resin reaction generates significant quantities of noncondensable gases, which would pressurize the column. To prevent the column from rupturing during such events, rupture disks are installed on the column vent lines. The venting analysis models accelerating rate calorimeter (ARC) tests and data from tests that were performed in a vented test vessel with a rupture disk. The tests showed that the pressure inside the test vessel continued to increase after the rupture disk opened, though at a slower rate than prior to the rupture. Calculated maximum discharge rates for the resin venting tests exceeded the measured rates of gas generation, so the vent size was sufficient to relieve the pressure in the test vessel if the vent flow rate was constant. The increase in the vessel pressure is modeled as a transient phenomenon associated with expansion of the resin slurry/gas mixture upon rupture of the disk. It is postulated that the maximum pressure at the end of this expansion is limited by energy minimization to approximately 1.5 times the rupture disk burst pressure. The magnitude of this pressure increase is consistent with the measured pressure transients. The results of this analysis demonstrate the need to allow for a margin between the design pressure and the rupture disk burst pressure in similar applications.

  17. Identification of possible recent water/lava source fissures in the Cerberus Plains: stratigraphic and crater count age constraints

    NASA Astrophysics Data System (ADS)

    Thomas, Rebecca J.

    2013-04-01

    The Cerberus plains are one of the youngest surfaces on Mars. They are thought to have been formed by lava and/or water flows, but there is considerable debate regarding the source of this material. Much of the material forming the western plains, including the Athabasca Valles outflow channels, appears to have flowed from the region of the Cerberus Fossae graben system [1,2,3] and limited areas forming the eastern plains may have been erupted by low shield volcanoes [4,5]. However, flow of material from west to east is obstructed by a ridge centred on 157°E, 7°N and, prior to this study, vents which might be the source of fluid of a low enough viscosity to form the majority of the flat eastern plains had not been identified. We studied new HiRISE (25cm/px, High Resolution Science Imaging Experiment) images of the ridge between the east and west plains and observed possible source vents for this material: the ridge is cut by a series of pits and fissures which lie at the heads of flows and channels extending towards the surrounding plains. In order to establish the stratigraphic relationships between the vents and plains, this study produced large scale geomorphological maps based on the HiRISE images. The mapping showed that both incised channels and leveed flows extend onto the plain to the south of the ridge and that these were the final phase of plains-forming activity in that region. Conversely, to the north, ridge-sourced deposits only form the plains surface close to the ridge - beyond that, they are overlain by large-scale regional flows that appear to have originated from the direction of Athabasca Valles. In the southeast, a large-scale flow which does not emanate from this ridge forms the plains surface, but there is evidence that the youngest outflow activity from the ridge was contemporaneous with emplacement of this unit. We also performed crater counts to age-date the surfaces and these indicate that plains-forming and ridge-sourced units are of a

  18. Examination of frit vent from Sixty-Watt Heat Source simulant fueled clad vent set

    SciTech Connect

    Ulrich, G.B.

    1995-11-01

    The flow rate and the metallurgical condition of a frit vent from a simulant-fueled clad vent set (CVS) that had been hot isostatically pressed (HIP) for the Sixty-Watt Heat Source program were evaluated. The flow rate form the defueled vent cup subassembly was reduced approximately 25% from the original flow rate. No obstructions were found to account for the reduced flow rate. Measurements indicate that the frit vent powder thickness was reduced about 30%. Most likely, the powder was compressed during the HIP operation, which increased the density of the powder layer and thus reduced the flow rate of the assembly. All other observed manufacturing attributes appeared to be normal, but the vent hole activation technique needs further refinement before it is used in applications requiring maximum CVS integrity.

  19. Automatic venting valve for gas storage tank

    SciTech Connect

    Johnson, H.

    1986-12-02

    A control valve is described for blocking atmospheric venting of gas fumes contained within a gasoline storage tank during tanker refill operations. The gasoline tank includes a venting tube coupled to open space within the top of the tank to provide air intake for pressure equalization as gasoline is gradually removed from the tank, the control valve comprising: a. a rigid, tubular valve casing having a top opening, a bottom opening and a flow channel therebetween; b. means for attaching the bottom end of the casing to an upper end of the venting tube such that the valve flow channel forms a continuation venting path for the venting tube; c. first and second valve seats and an intermediate seating member coupled to the casing and at least partially contained within the flow channel. The seating member is configured in shape and size to form restricted air space between the seating member and a surrounding wall of the flow channel to be reversibly displaceable in response to fume exhaust expelled during refill operations.

  20. Comparison of Various Concentrations of Tricalcium Phosphate Nanoparticles on Mechanical Properties and Remineralization of Fissure Sealants

    PubMed Central

    Tavassoli-Hojjati, Sara; Atai, Mohammad; Haghgoo, Roza; Rahimian-Imam, Sara; Kameli, Somayeh; Ahmaian-Babaki, Fatemeh; Hamzeh, Faezeh; Ahmadyar, Maryam

    2014-01-01

    Objective: The aim of this study was to investigate the mechanical properties (flexural strength, micro-shear bond strength) and remineralizing potential of fissure sealants by adding various concentrations of β-tricalcium phosphate nanoparticles. Materials and Methods: This in-vitro study consisted of five experimental groups containing prepared nano-fisssure sealants (1–5 wt.% β-TCP nanoparticles) and two control groups containing a prepared and a commercial fissure sealant. Flexural/micro-shear bond strength values were measured using Zwick test machine. Cavities on sixty healthy premolar teeth were filled with the fissure sealants containing 0–5 wt.% of nano β-TCP. The samples were assessed for remineralization under scanning electron microscopy (SEM) and EDAX. Kolmogorov-Smirnov test, One-way ANOVA and Tukey’s Post Hoc analysis/HSD were used to analyze the data. Results: There was no significant difference between the flexural strengths/elastic modulus of the 0–5 wt.% nano β-TCP groups (p>0.05). The average flexural strength/elastic modulus of the prepared fissure sealant group (0%) was significantly higher than the commercial fissure sealant group (Clinpro) (p<0.05). There was no significant difference between micro-shear bond strengths of the experimental groups (1–5 wt.%), and between the commercial and the prepared (0%) fissure sealant groups (p>0.05). Examining the samples under SEM showed a significant increase in thickness of the intermediate layer with increasing concentrations of β-TCP nanoparticles (p<0.05). Conclusion: Addition of 1–5 wt.% β-TCP nanoparticles to the fissure sealants significantly increased the remineralization potential without affecting the mechanical properties. PMID:25584048

  1. Retention of resin-based filled and unfilled pit and fissure sealants: A comparative clinical study

    PubMed Central

    Reddy, V. Rajashekar; Chowdhary, Nagalakshmi; Mukunda, K. S.; Kiran, N. K.; Kavyarani, B. S.; Pradeep, M. C.

    2015-01-01

    Background and Objectives: The most caries-susceptible period of a permanent first molar tooth is the eruption phase, during which the enamel is not fully matured and it is usually difficult for the child to clean the erupting tooth surfaces. Sealing occlusal pits and fissures with resin-based pit and fissure sealants is a proven method to prevent occlusal caries. The difference in the viscosity of the sealants differs in the penetration into pit and fissures and abrasive wear resistance property due to the addition of filler particles. The present study was conducted to evaluate and compare the retention of the resin-based filled (Helioseal F, Ivoclar Vivadent) and unfilled (Clinpro, 3M ESPE) pit and fissure sealants, which is important for their effectiveness. Materials and Methods: Fifty-six children between the age group of 6 and 9 years, with all four newly erupted permanent first molars were selected. Sealants were applied randomly using split mouth design technique on permanent first molars. Evaluation of sealant retention was performed at regular intervals over 12 months, using Simonsen's criteria at 2nd, 4th, 6th, 8th, 10th and 12th month. The results were subjected to statistical analysis. Results: At the end of our study period (12th month), 53.57% showed complete retention, 37.50% showed partial retention, and 8.83% showed complete missing of resin-based filled (Helioseal F) pit and fissure sealant. And, 64.29% showed complete retention, 32.14% showed partial retention, and 3.57% showed complete missing of resin-based unfilled (Clinpro) pit and fissure sealant. This difference in retention rates between filled and unfilled pit and fissure sealants was not statistically significant. Conclusion: The difference in retention rates between Helioseal F and Clinpro was not statistically significant, but Clinpro (unfilled) sealant showed slightly higher retention rates and clinically better performance than Helioseal F (filled). PMID:25821368

  2. Investigations Into Tank Venting for Propellant Resupply

    NASA Technical Reports Server (NTRS)

    Hearn, H. C.; Harrison, Robert A. (Technical Monitor)

    2002-01-01

    Models and simulations have been developed and applied to the evaluation of propellant tank ullage venting, which is integral to one approach for propellant resupply. The analytical effort was instrumental in identifying issues associated with resupply objectives, and it was used to help develop an operational procedure to accomplish the desired propellant transfer for a particular storable bipropellant system. Work on the project was not completed, and several topics have been identified as requiring further study; these include the potential for liquid entrainment during the low-g and thermal/freezing effects in the vent line and orifice. Verification of the feasibility of this propellant venting and resupply approach still requires additional analyses as well as testing to investigate the fluid and thermodynamic phenomena involved.

  3. Medium Fidelity Simulation of Oxygen Tank Venting

    NASA Technical Reports Server (NTRS)

    Sweet, Adam; Kurien, James; Lau, Sonie (Technical Monitor)

    2001-01-01

    The item to he cleared is a medium-fidelity software simulation model of a vented cryogenic tank. Such tanks are commonly used to transport cryogenic liquids such as liquid oxygen via truck, and have appeared on liquid-fueled rockets for decades. This simulation model works with the HCC simulation system that was developed by Xerox PARC and NASA Ames Research Center. HCC has been previously cleared for distribution. When used with the HCC software, the model generates simulated readings for the tank pressure and temperature as the simulated cryogenic liquid boils off and is vented. Failures (such as a broken vent valve) can be injected into the simulation to produce readings corresponding to the failure. Release of this simulation will allow researchers to test their software diagnosis systems by attempting to diagnose the simulated failure from the simulated readings. This model does not contain any encryption software nor can it perform any control tasks that might be export controlled.

  4. Why does a mature volcano need new vents? The case of the New Southeast Crater at Etna

    NASA Astrophysics Data System (ADS)

    Acocella, Valerio; Neri, Marco; Behncke, Boris; Bonforte, Alessandro; Del Negro, Ciro; Ganci, Gaetana

    2016-06-01

    Mature volcanoes usually erupt from a persistent summit crater. Permanent shifts in vent location are expected to occur after significant structural variations and are seldom documented. Here we provide such an example that recently occurred at Etna. Eruptive activity at Mount Etna during 2007 focused at the Southeast Crater (SEC), the youngest (formed in 1971) and most active of the four summit craters, and consisted of six paroxysmal episodes. The related erupted volumes, determined by field-based measurements and radiant heat flux curves measured by satellite, totalled 8.67 x 106 m3. The first four episodes occurred, between late-March and early-May, from the summit of the SEC and short fissures on its flanks. The last two episodes occurred, in September and November, from a new vent ("pit crater" or "proto-NSEC") at the SE base of the SEC cone; this marked the definitive demise of the old SEC and the shift to the new vent. The latter, fed by NW-SE striking dikes propagating from the SEC conduit, formed since early 2011 an independent cone (the New Southeast Crater, or "NSEC") at the base of the SEC. Detailed geodetic reconstruction and structural field observations allow defining the surface deformation pattern of Mount Etna in the last decade. These suggest that the NSEC developed under the NE-SW trending tensile stresses on the volcano summit promoted by accelerated instability of the NE flank of the volcano during inflation periods. The development of the NSEC is not only important from a structural point of view, as its formation may also lead to an increase in volcanic hazard. The case of the NSEC at Etna here reported shows how flank instability may control the distribution and impact of volcanism, including the prolonged shift of the summit vent activity in a mature volcano.

  5. Spatial Compilation of Holocene Volcanic Vents in the Western Conterminous United States

    NASA Astrophysics Data System (ADS)

    Ramsey, D. W.; Siebert, L.

    2015-12-01

    A spatial compilation of all known Holocene volcanic vents in the western conterminous United States has been assembled. This compilation records volcanic vent location (latitude/longitude coordinates), vent type (cinder cone, dome, etc.), geologic map unit description, rock type, age, numeric age and reference (if dated), geographic feature name, mapping source, and, where available, spatial database source. Primary data sources include: USGS geologic maps, USGS Data Series, the Smithsonian Global Volcanism Program (GVP) catalog, and published journal articles. A total of 726 volcanic vents have been identified from 45 volcanoes or volcanic fields spanning ten states. These vents are found along the length of the Cascade arc in the Pacific Northwest, widely around the Basin and Range province, and at the southern margin of the Colorado Plateau into New Mexico. The U.S. Geological Survey (USGS) National Volcano Early Warning System (NVEWS) identifies 28 volcanoes and volcanic centers in the western conterminous U.S. that pose moderate, high, or very high threats to surrounding communities based on their recent eruptive histories and their proximity to vulnerable people, property, and infrastructure. This compilation enhances the understanding of volcano hazards that could threaten people and property by providing the context of where Holocene eruptions have occurred and where future eruptions may occur. Locations in this compilation can be spatially compared to located earthquakes, used as generation points for numerical hazard models or hazard zonation buffering, and analyzed for recent trends in regional volcanism and localized eruptive activity.

  6. Composition of gases vented from a condenser

    SciTech Connect

    Lyon, R.N.

    1980-08-01

    Designers of systems that involve condensers often need to predict the amount of process vapor that accompanies the noncondensable gases that are vented from the condensers. An approximation is given that appears to provide, in many cases, reasonably accurate values for the mole ratio of process vapor to noncondensable gases in the vented mixture. The approximation is particularly applicable to flash and direct-contact power systems for geothermal brines and ocean thermal energy conversion (OTEC). More regorous relationships are available for exceptional cases.

  7. Vented Cavity Radiant Barrier Assembly And Method

    DOEpatents

    Dinwoodie, Thomas L.; Jackaway, Adam D.

    2000-05-16

    A vented cavity radiant barrier assembly (2) includes a barrier (12), typically a PV module, having inner and outer surfaces (18, 22). A support assembly (14) is secured to the barrier and extends inwardly from the inner surface of the barrier to a building surface (14) creating a vented cavity (24) between the building surface and the barrier inner surface. A low emissivity element (20) is mounted at or between the building surface and the barrier inner surface. At least part of the cavity exit (30) is higher than the cavity entrance (28) to promote cooling air flow through the cavity.

  8. Geological and geochemical controls on the distribution of Alviniconcha vent snail symbioses: Have we finally linked mantle to microbe? (Invited)

    NASA Astrophysics Data System (ADS)

    Girguis, P. R.; Beinart, R.; Sanders, J.; Seewald, J.

    2010-12-01

    Gastropods of the genus Alviniconcha are found at hydrothermal vent fields in the Western Pacific, and have been reported to associate with either γ- or ɛ-Proteobacterial endosymbionts. These symbionts harness energy from the oxidation of chemicals in vent fluid to fix inorganic carbon and are the primary source of nutrition for the holobiont. An extensive sampling effort during a recent expedition to the Eastern Lau Spreading Center (ELSC) has revealed that Alviniconcha host both previously observed symbiont types, as well as an additional γ- proteobacterial symbiont. Specifically, we collected 266 Alviniconcha individuals from four vent fields along the spreading center (30-140km apart) which span the north-south transition from fast spreading, basalt-hosted to slower spreading, andesite-hosted fields. Vent fluids from each field were also analyzed for the abundances of aqueous volatile and non-volatile species. The symbionts of all collected Alviniconcha were genotyped using restriction fragment length polymorphism analysis as well as quantitative PCR. Individuals were found to primarily host one of the three symbiont genotypes (two γ- and one ɛ-Proteobacteria). Notably, we found that the two northern-most sites (basalt-hosted vents) were greatly dominated by individuals with the ɛ-Proteobacterial symbiont, while the two southern sites (andesite-hosted vents) were dominated by individuals hosting one of the two γ-Proteobacterial symbionts. This pattern corresponds to differences in the aqueous chemistry of the vent fluids along the spreading center. In particular, we have measured higher concentrations of hydrogen and hydrogen sulfide in the vent fluids at the northern sites than in the fluids of the southern sites. We posit that vent chemistry -which is influenced by subsurface water-rock interactions- may be influencing the dominance of each symbiont type along the ELSC. The putative implications for the role that geology and geochemistry plays in

  9. Quantifying diffuse and discrete venting at the Tour Eiffel vent site, Lucky Strike hydrothermal field

    NASA Astrophysics Data System (ADS)

    Mittelstaedt, Eric; EscartíN, Javier; Gracias, Nuno; Olive, Jean-Arthur; Barreyre, Thibaut; Davaille, Anne; Cannat, Mathilde; Garcia, Rafael

    2012-04-01

    The relative heat carried by diffuse versus discrete venting of hydrothermal fluids at mid-ocean ridges is poorly constrained and likely varies among vent sites. Estimates of the proportion of heat carried by diffuse flow range from 0% to 100% of the total axial heat flux. Here, we present an approach that integrates imagery, video, and temperature measurements to accurately estimate this partitioning at a single vent site, Tour Eiffel in the Lucky Strike hydrothermal field along the Mid-Atlantic Ridge. Fluid temperatures, photographic mosaics of the vent site, and video sequences of fluid flow were acquired during the Bathyluck'09 cruise (Fall, 2009) and the Momarsat'10 cruise (Summer, 2010) to the Lucky Strike hydrothermal field by the ROV Victor6000 aboard the French research vessel the "Pourquoi Pas"? (IFREMER, France). We use two optical methods to calculate the velocities of imaged hydrothermal fluids: (1) for diffuse venting, Diffuse Flow Velocimetry tracks the displacement of refractive index anomalies through time, and (2) for discrete jets, Particle Image Velocimetry tracks eddies by cross-correlation of pixel intensities between subsequent images. To circumvent video blurring associated with rapid velocities at vent orifices, exit velocities at discrete vents are calculated from the best fit of the observed velocity field to a model of a steady state turbulent plume where we vary the model vent radius and fluid exit velocity. Our results yield vertical velocities of diffuse effluent between 0.9 cm s-1 and 11.1 cm s-1 for fluid temperatures between 3°C and 33.5°C above that of ambient seawater, and exit velocities of discrete jets between 22 cm s-1 and 119 cm s-1 for fluid temperatures between 200°C and 301°C above ambient seawater. Using the calculated fluid velocities, temperature measurements, and photo mosaics of the actively venting areas, we calculate a heat flux due to diffuse venting from thin fractures of 3.15 ± 2.22 MW, discrete venting of

  10. Automatic recognition of lung lobes and fissures from multislice CT images

    NASA Astrophysics Data System (ADS)

    Zhou, Xiangrong; Hayashi, Tatsuro; Hara, Takeshi; Fujita, Hiroshi; Yokoyama, Ryujiro; Kiryu, Takuji; Hoshi, Hiroaki

    2004-05-01

    Computer-aided diagnosis (CAD) has been expected to help radiologists to improve the accuracy of abnormality detection and reduce the burden during CT image interpretations. In order to realize such functions, automated segmentations of the target organ regions are always required by CAD systems. This paper describes a fully automatic processing procedure, which is designed to identify inter-lobe fissures and divide lung into five lobe regions. The lung fissures are disappeared very fuzzy and indefinite in CT images, so that it is very difficult to extract fissures directly based on its CT values. We propose a method to solve this problem using the anatomy knowledge of human lung. We extract lung region firstly and then recognize the structures of lung vessels and bronchus. Based on anatomy knowledge, we classify the vessels and bronchus on a lobe-by-lobe basis and estimate the boundary of each lobe region as the initial fissure locations. Within those locations, we extract lung fissures precisely based on an edge detection method and divide lung regions into five lung lobes lastly. The performance of the proposed method was evaluated using 9 patient cases of high-resolution multi-slice chest CT images; the improvement has been confirmed with the reliable recognition results.

  11. In Vitro Comparison of Microleakage of Two Materials Used as Pit and Fissure Sealants

    PubMed Central

    Bahrololoomi, Zahra; Soleymani, Aliasghar; Heydari, Zahra

    2011-01-01

    Background and aims Marginal seal of the material is extremely important in fissure sealant therapy. The aim of this study was to investigate microleakage of flowable composite resins and conventional fissure sealants with or without dentin bonding agent. Materials and methods The occlusal surface of 60 intact extracted human premolars, divided into four groups, were cleaned with pumice/slurry, etched with 37% phosphoric acid for 15 seconds, rinsed and dried. Groups were treated differ-ently: Excite bonding agent followed by Helioseal F fissure sealant in group1; Helioseal F alone in group 2; Excite bonding agent followed by Tetric Flow in group 3; and Tetric Flow alone in group 4. Light-curing was done after each application. After thermocycling, the whole surface of each specimen was coated with nail varnish except for one millimeter around the fissure sealant. The teeth were immersed in 2% basic fuchsin for 24 hours and then sectioned buccolingually. The sections were analyzed for leakage under a stereomicroscope. Data was analyzed by Kruskal-Wallis and Mann-Whitney tests at asignificance level of P < 0.05. Results There were no statistically significant differencesbetween the study groups in terms of the mean microleakage scores (P > 0.05), except for groups 2 and 4 (P = 0.002) and groups 3 and 4 (P = 0.033). Conclusion Use of a flowable composite with bonding agent is a good alternative for sealing pits and fissures; however, further in vitro and in vivo studies are necessary. PMID:22991611

  12. Long-distance magma transport from arc volcanoes inferred from the submarine eruptive fissures offshore Izu-Oshima volcano, Izu-Bonin arc

    NASA Astrophysics Data System (ADS)

    Ishizuka, Osamu; Geshi, Nobuo; Kawanabe, Yoshihisa; Ogitsu, Itaru; Taylor, Rex N.; Tuzino, Taqumi; Sakamoto, Izumi; Arai, Kohsaku; Nakano, Shun

    2014-09-01

    Long-distance lateral magma transport away from volcanic centers in island arcs is emerging as a common phenomenon where the regional stress regime is favorable. It should also be recognized as an important factor in the construction and growth of island arcs, and a potential trigger for devastating eruptions. In this contribution, we report on recent investigations into the magma dynamics of Izu-Oshima volcano, an active basaltic volcano with an extensive fissure system. Izu-Oshima is flanked by numerous, subparallel NW-SE trending submarine ridges extending up to 22 km to the NW and the SE from the central vent. During a recent submersible survey we have identified that these ridges are fissures which erupted basaltic spatter and lava flows. Furthermore, lavas are petrographically similar along each ridge, while there are noticeable differences between ridges. The subparallel ridges are observed to transect a series of seamounts - the Izu-Tobu monogenetic volcanoes - which are dispersed across this area of the rear-arc. However, there are consistent petrographic and chemical differences between these seamounts and the ridges, indicating that they have different magma sources, yet, they are essentially bounding each other in dive tracks. The most appropriate scenario for their development is one where the Izu-Tobu Volcanoes are fed by an "in-situ" underlying source, while the NW-SE ridges are fed by lateral magma transport from Izu-Oshima. Magma erupted from each ridge is of a consistent geochemistry along its length, but has experienced crystal fractionation and some plagioclase accumulation. Compositions of the ridges are also very similar to lavas from the subaerial cones that can be traced down the flanks of Izu-Oshima. This implies that pairs of subaerial cones and submarine ridges represent the locus of magma transport events away from the storage system beneath Izu-Oshima. Hence, magma from this crustal reservoir moved upward to feed the on-edifice cones

  13. 46 CFR 38.20-1 - Venting-T/ALL.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... relief valve and the vent outlets. (h) Provisions shall be made to drain condensate from the vent header piping. Special precautions shall insure that condensate does not accumulate at or near the relief...

  14. 46 CFR 38.20-1 - Venting-T/ALL.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... relief valve and the vent outlets. (h) Provisions shall be made to drain condensate from the vent header piping. Special precautions shall insure that condensate does not accumulate at or near the relief...

  15. 46 CFR 38.20-1 - Venting-T/ALL.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... relief valve and the vent outlets. (h) Provisions shall be made to drain condensate from the vent header piping. Special precautions shall insure that condensate does not accumulate at or near the relief...

  16. Flow fields of low pressure vent exhausts

    NASA Technical Reports Server (NTRS)

    Scialdone, John J.

    1989-01-01

    The flow field produced by low pressure gas vents are described based on experimental data obtained from tests in a large vacuum chamber. The gas density, pressure, and flux at any location in the flow field are calculated based on the vent plume description and the knowledge of the flow rate and velocity of the venting gas. The same parameters and the column densities along a specified line of sight traversing the plume are also obtained and shown by a computer-generated graphical representation. The fields obtained with a radially scanning Pitot probe within the exhausting gas are described by a power of the cosine function, the mass rate and the distance from the exit port. The field measurements were made for gas at pressures ranging from 2 to 50 torr venting from pipe fittings with diameters of 3/16 inch to 1-1/2 inches I.D. (4.76 mm to 38.1 mm). The N(2) mass flow rates ranged from 2E-4 to 3.7E-1 g/s.

  17. Flow fields of low pressure vent exhausts

    NASA Technical Reports Server (NTRS)

    Scialdone, John J.

    1990-01-01

    The flow field produced by low pressure gas vents are described based on experimental data obtained from tests in a large vacuum chamber. The gas density, pressure, and flux at any location in the flow field are calculated based on the vent plume description and the knowledge of the flow rate and velocity of the venting gas. The same parameters and the column densities along a specified line of sight traversing the plume are also obtained and shown by a computer generated graphical representation. The fields obtained with a radically scanning Pitot probe within the exhausting gas are described by a power of the cosine function, the mass rate, and the distance from the exit port. The field measurements were made for gas at pressures ranging from 2 to 50 torr venting from pipe fittings with diameters to 3/16 to 1-1/2 inches I.D. (4.76 to 38.1 mm). The N2 mass flow rates ranged from 2E-4 to 3.7E-1 g/s.

  18. 33 CFR 159.61 - Vents.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 33 Navigation and Navigable Waters 2 2011-07-01 2011-07-01 false Vents. 159.61 Section 159.61 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) POLLUTION MARINE... to minimize clogging by either the contents of the tank or climatic conditions such as snow or ice....

  19. 33 CFR 159.61 - Vents.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 33 Navigation and Navigable Waters 2 2010-07-01 2010-07-01 false Vents. 159.61 Section 159.61 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) POLLUTION MARINE... to minimize clogging by either the contents of the tank or climatic conditions such as snow or ice....

  20. Preoperational test report, vent building ventilation system

    SciTech Connect

    Clifton, F.T.

    1997-11-04

    This represents a preoperational test report for Vent Building Ventilation Systems, Project W-030. Project W-030 provides a ventilation upgrade for the four Aging Waste Facility tanks. The system provides Heating, Ventilation, and Air Conditioning (HVAC) for the W-030 Ventilation Building. The tests verify correct system operation and correct indications displayed by the central Monitor and Control System.

  1. 46 CFR 98.25-70 - Venting.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 4 2011-10-01 2011-10-01 false Venting. 98.25-70 Section 98.25-70 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) CARGO AND MISCELLANEOUS VESSELS SPECIAL CONSTRUCTION, ARRANGEMENT, AND OTHER PROVISIONS FOR CERTAIN DANGEROUS CARGOES IN BULK Anhydrous Ammonia in Bulk §...

  2. 46 CFR 98.25-70 - Venting.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 4 2014-10-01 2014-10-01 false Venting. 98.25-70 Section 98.25-70 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) CARGO AND MISCELLANEOUS VESSELS SPECIAL CONSTRUCTION, ARRANGEMENT, AND OTHER PROVISIONS FOR CERTAIN DANGEROUS CARGOES IN BULK Anhydrous Ammonia in Bulk §...

  3. 46 CFR 98.25-70 - Venting.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 4 2010-10-01 2010-10-01 false Venting. 98.25-70 Section 98.25-70 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) CARGO AND MISCELLANEOUS VESSELS SPECIAL CONSTRUCTION, ARRANGEMENT, AND OTHER PROVISIONS FOR CERTAIN DANGEROUS CARGOES IN BULK Anhydrous Ammonia in Bulk §...

  4. 46 CFR 98.25-70 - Venting.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 4 2013-10-01 2013-10-01 false Venting. 98.25-70 Section 98.25-70 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) CARGO AND MISCELLANEOUS VESSELS SPECIAL CONSTRUCTION, ARRANGEMENT, AND OTHER PROVISIONS FOR CERTAIN DANGEROUS CARGOES IN BULK Anhydrous Ammonia in Bulk §...

  5. 46 CFR 98.25-70 - Venting.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 4 2012-10-01 2012-10-01 false Venting. 98.25-70 Section 98.25-70 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) CARGO AND MISCELLANEOUS VESSELS SPECIAL CONSTRUCTION, ARRANGEMENT, AND OTHER PROVISIONS FOR CERTAIN DANGEROUS CARGOES IN BULK Anhydrous Ammonia in Bulk §...

  6. Computer controlled vent and pressurization system

    NASA Technical Reports Server (NTRS)

    Cieslewicz, E. J.

    1975-01-01

    The Centaur space launch vehicle airborne computer, which was primarily used to perform guidance, navigation, and sequencing tasks, was further used to monitor and control inflight pressurization and venting of the cryogenic propellant tanks. Computer software flexibility also provided a failure detection and correction capability necessary to adopt and operate redundant hardware techniques and enhance the overall vehicle reliability.

  7. Electrochemical cell having improved pressure vent

    DOEpatents

    Dean, Kevin; Holland, Arthur; Fillmore, Donn

    1993-01-01

    The electrochemical cell of the instant invention includes a case having a gas outlet, one or more positive electrodes positioned within the case, one or more negative electrodes positioned within the case electrode separators positioned between the positive and negative electrodes, electrolyte positioned within the case, and a pressure vent for releasing internal pressure occurring in the case to the surrounding atmosphere. The pressure vent is affixed to the case covering the gas outlet, the pressure vent includes a vent housing having a hollow interior area in gaseous communication with the surrounding atmosphere and the interior of the case via the gas outlet, a pressure release piston positioned within the hollow interior area, the pressure release piston sized to surround the gas outlet and having a seal groove configured to encapsulate all but one surface of a seal mounted within the seal groove, leaving the non-encapsulated surface of the seal exposed, and a compression spring positioned to urge the pressure release piston to compress the seal in the seal groove and block the gas outlet in the case.

  8. 24 CFR 3280.710 - Venting, ventilation and combustion air.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... HOUSING AND URBAN DEVELOPMENT MANUFACTURED HOME CONSTRUCTION AND SAFETY STANDARDS Heating, Cooling and...: (1) An integral vent system listed or certified as part of the appliance. (2) A venting system... appliance listing and the appliance manufacturer's instructions. (b) Venting and combustion air...

  9. 40 CFR 65.62 - Process vent group determination.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 16 2014-07-01 2014-07-01 false Process vent group determination. 65.62 Section 65.62 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) CONSOLIDATED FEDERAL AIR RULE Process Vents § 65.62 Process vent group determination. (a) Group status. The owner or operator of a...

  10. 33 CFR 183.520 - Fuel tank vent systems.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 33 Navigation and Navigable Waters 2 2010-07-01 2010-07-01 false Fuel tank vent systems. 183.520...) BOATING SAFETY BOATS AND ASSOCIATED EQUIPMENT Fuel Systems Equipment Standards § 183.520 Fuel tank vent systems. (a) Each fuel tank must have a vent system that prevents pressure in the tank from exceeding...

  11. 14 CFR 27.975 - Fuel tank vents.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 14 Aeronautics and Space 1 2014-01-01 2014-01-01 false Fuel tank vents. 27.975 Section 27.975... STANDARDS: NORMAL CATEGORY ROTORCRAFT Powerplant Fuel System § 27.975 Fuel tank vents. (a) Each fuel tank... system must be designed to minimize spillage of fuel through the vents to an ignition source in the...

  12. 40 CFR 63.1406 - Reactor batch process vent provisions.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 12 2013-07-01 2013-07-01 false Reactor batch process vent provisions... Resins § 63.1406 Reactor batch process vent provisions. (a) Emission standards. Owners or operators of reactor batch process vents located at new or existing affected sources shall comply with paragraph...

  13. 40 CFR 63.1406 - Reactor batch process vent provisions.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 12 2012-07-01 2011-07-01 true Reactor batch process vent provisions... § 63.1406 Reactor batch process vent provisions. (a) Emission standards. Owners or operators of reactor... reactor batch process vent located at a new affected source shall control organic HAP emissions...

  14. 40 CFR 63.1406 - Reactor batch process vent provisions.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 11 2010-07-01 2010-07-01 true Reactor batch process vent provisions... § 63.1406 Reactor batch process vent provisions. (a) Emission standards. Owners or operators of reactor... reactor batch process vent located at a new affected source shall control organic HAP emissions...

  15. 40 CFR 63.1406 - Reactor batch process vent provisions.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 11 2011-07-01 2011-07-01 false Reactor batch process vent provisions... § 63.1406 Reactor batch process vent provisions. (a) Emission standards. Owners or operators of reactor... reactor batch process vent located at a new affected source shall control organic HAP emissions...

  16. 40 CFR 63.1406 - Reactor batch process vent provisions.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 12 2014-07-01 2014-07-01 false Reactor batch process vent provisions... Resins § 63.1406 Reactor batch process vent provisions. (a) Emission standards. Owners or operators of reactor batch process vents located at new or existing affected sources shall comply with paragraph...

  17. 46 CFR 64.63 - Minimum emergency venting capacity.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 2 2010-10-01 2010-10-01 false Minimum emergency venting capacity. 64.63 Section 64.63... emergency venting capacity. (a) The total emergency venting capacity (Q) of the relief devices of an... in square feet. L=Latent heat of the product being vaporized at relieving conditions in Btu per...

  18. 40 CFR 63.1408 - Aggregate batch vent stream provisions.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... from all aggregate batch vent streams in the compliance demonstration required for reactor batch... comply with the mass emission limit for reactor batch process vents. ... 40 Protection of Environment 11 2010-07-01 2010-07-01 true Aggregate batch vent stream...

  19. 14 CFR 34.11 - Standard for fuel venting emissions.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... FUEL VENTING AND EXHAUST EMISSION REQUIREMENTS FOR TURBINE ENGINE POWERED AIRPLANES Engine Fuel Venting Emissions (New and In-Use Aircraft Gas Turbine Engines) § 34.11 Standard for fuel venting emissions. (a) No... turbine engine subject to the subpart. This paragraph is directed at the elimination of...

  20. 14 CFR 34.11 - Standard for fuel venting emissions.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... FUEL VENTING AND EXHAUST EMISSION REQUIREMENTS FOR TURBINE ENGINE POWERED AIRPLANES Engine Fuel Venting Emissions (New and In-Use Aircraft Gas Turbine Engines) § 34.11 Standard for fuel venting emissions. (a) No... turbine engine subject to the subpart. This paragraph is directed at the elimination of...

  1. 14 CFR 34.11 - Standard for fuel venting emissions.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... FUEL VENTING AND EXHAUST EMISSION REQUIREMENTS FOR TURBINE ENGINE POWERED AIRPLANES Engine Fuel Venting Emissions (New and In-Use Aircraft Gas Turbine Engines) § 34.11 Standard for fuel venting emissions. (a) No... turbine engine subject to the subpart. This paragraph is directed at the elimination of...

  2. 14 CFR 34.11 - Standard for fuel venting emissions.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... FUEL VENTING AND EXHAUST EMISSION REQUIREMENTS FOR TURBINE ENGINE POWERED AIRPLANES Engine Fuel Venting Emissions (New and In-Use Aircraft Gas Turbine Engines) § 34.11 Standard for fuel venting emissions. (a) No... turbine engine subject to the subpart. This paragraph is directed at the elimination of...

  3. 46 CFR 153.358 - Venting system flow capacity.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 5 2010-10-01 2010-10-01 false Venting system flow capacity. 153.358 Section 153.358 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) CERTAIN BULK DANGEROUS CARGOES SHIPS... Venting Systems § 153.358 Venting system flow capacity. (a) The cross-sectional flow area of any...

  4. "Venting" in the Workplace: An Ethnographic Study among Resident Assistants.

    ERIC Educational Resources Information Center

    Burchard, Brendon

    The term "venting" has been used interchangeably with negatively-connotated words like "outburst,""bitching,""complaining," and with more functional words like "disclosing." A literature review of venting showed that researchers have approached the term from multiple perspectives. Because of the ambiguity of what venting is or is not, why it is…

  5. 46 CFR 153.354 - Venting system inlet.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 5 2012-10-01 2012-10-01 false Venting system inlet. 153.354 Section 153.354 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) CERTAIN BULK DANGEROUS CARGOES SHIPS CARRYING BULK LIQUID, LIQUEFIED GAS, OR COMPRESSED GAS HAZARDOUS MATERIALS Design and Equipment Cargo Venting Systems § 153.354 Venting system inlet....

  6. 46 CFR 151.15-6 - Venting piping.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 5 2010-10-01 2010-10-01 false Venting piping. 151.15-6 Section 151.15-6 Shipping COAST... LIQUID HAZARDOUS MATERIAL CARGOES Tanks § 151.15-6 Venting piping. (a) The back pressure in the relief... condensate which may accumulate in the vent piping. (b)...

  7. 46 CFR 151.15-6 - Venting piping.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 5 2011-10-01 2011-10-01 false Venting piping. 151.15-6 Section 151.15-6 Shipping COAST... LIQUID HAZARDOUS MATERIAL CARGOES Tanks § 151.15-6 Venting piping. (a) The back pressure in the relief... condensate which may accumulate in the vent piping. (b)...

  8. 33 CFR 183.520 - Fuel tank vent systems.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 33 Navigation and Navigable Waters 2 2012-07-01 2012-07-01 false Fuel tank vent systems. 183.520...) BOATING SAFETY BOATS AND ASSOCIATED EQUIPMENT Fuel Systems Equipment Standards § 183.520 Fuel tank vent systems. (a) Each fuel tank must have a vent system that prevents pressure in the tank from exceeding...

  9. 14 CFR 121.261 - Vent and drain lines.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 3 2010-01-01 2010-01-01 false Vent and drain lines. 121.261 Section 121... drain lines. All vent and drain lines and their fittings, that are located in a designated fire zone... the rupture or breakage of any vent or drain line may result in a fire hazard....

  10. 40 CFR 63.1321 - Batch process vents provisions.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 11 2010-07-01 2010-07-01 true Batch process vents provisions. 63.1321... Standards for Hazardous Air Pollutant Emissions: Group IV Polymers and Resins § 63.1321 Batch process vents provisions. (a) Batch process vents. Except as specified in paragraphs (b) through (d) of this...

  11. Discovery of a black smoker vent field and vent fauna at the Arctic Mid-Ocean Ridge

    PubMed Central

    Pedersen, Rolf B.; Rapp, Hans Tore; Thorseth, Ingunn H.; Lilley, Marvin D.; Barriga, Fernando J. A. S.; Baumberger, Tamara; Flesland, Kristin; Fonseca, Rita; Früh-Green, Gretchen L.; Jorgensen, Steffen L.

    2010-01-01

    The Arctic Mid-Ocean Ridge (AMOR) represents one of the most slow-spreading ridge systems on Earth. Previous attempts to locate hydrothermal vent fields and unravel the nature of venting, as well as the provenance of vent fauna at this northern and insular termination of the global ridge system, have been unsuccessful. Here, we report the first discovery of a black smoker vent field at the AMOR. The field is located on the crest of an axial volcanic ridge (AVR) and is associated with an unusually large hydrothermal deposit, which documents that extensive venting and long-lived hydrothermal systems exist at ultraslow-spreading ridges, despite their strongly reduced volcanic activity. The vent field hosts a distinct vent fauna that differs from the fauna to the south along the Mid-Atlantic Ridge. The novel vent fauna seems to have developed by local specialization and by migration of fauna from cold seeps and the Pacific. PMID:21119639

  12. Evidence for Hydrothermal Vents as "Biogeobatteries" (Invited)

    NASA Astrophysics Data System (ADS)

    Nielsen, M. E.; Girguis, P. R.

    2010-12-01

    Hydrothermal vents are unique systems that play an important role in oceanic biogeochemical cycles. As chemically reduced hydrothermal fluid mixes with cold oxic seawater, minerals precipitate out of solution resulting in chimney structures composed largely of metal sulfides and anhydrite. Pyrite, which is a natural semi-conductor, is the primary sulfide mineral, but other minerals within chimneys are also conductive (e.g. chalcopyrite, wurtzite, and some iron oxides). Sulfide chimneys are also known to host an extensive endolithic microbial community. Accordingly, submarine hydrothermal systems appear to be examples of biogeobatteries, wherein conductive mineral assemblages span naturally occuring redox gradients and enable anaerobic microbes to access oxygen as an oxidant via extracellular electron transfer (or EET). To test this hypothesis, we ran a series of electrochemical laboratory experiments in which pyrite was used as an anode (in a vessel flushed with hydrothermal-like fluid). When placed in continuity with a carbon fiber cathode, pyrite was found to accept and conduct electrons from both abiotic and biological processes (microbial EET). Specifically, electrical current increased 4-fold (5 nA/m2 to 20 nA/m2) in response to inoculation with a slurry prepared from a hydrothermal vent sample. Inspection of the pyrite anode with SEM revealed ubiquitous coverage by microbes. DNA was extracted from the anodes and the inoculum, and was subjected to pyrosequencing to examine prokaryotic diversity. These data suggest that key microbial phylotypes were enriched upon the pyrite, implicating them in EET. In addition, we deployed an in situ experiment based on microbial fuel cell architecture with a graphite anode inserted into a vent wall coupled to a carbon fiber cathode outside the vent. We observed current production over the course of one year, implying microbial EET in situ. Via pyrosequencing, we observed that the microbial community on the anode was

  13. An experimental study on fracture mechanical behavior of rock-like materials containing two unparallel fissures under uniaxial compression

    NASA Astrophysics Data System (ADS)

    Huang, Yan-Hua; Yang, Sheng-Qi; Tian, Wen-Ling; Zeng, Wei; Yu, Li-Yuan

    2016-06-01

    Strength and deformability characteristics of rock with pre-existing fissures are governed by cracking behavior. To further research the effects of pre-existing fissures on the mechanical properties and crack coalescence process, a series of uniaxial compression tests were carried out for rock-like material with two unparallel fissures. In the present study, cement, quartz sand, and water were used to fabricate a kind of brittle rock-like material cylindrical model specimen. The mechanical properties of rock-like material specimen used in this research were all in good agreement with the brittle rock materials. Two unparallel fissures (a horizontal fissure and an inclined fissure) were created by inserting steel during molding the model specimen. Then all the pre-fissured rock-like specimens were tested under uniaxial compression by a rock mechanics servo-controlled testing system. The peak strength and Young's modulus of pre-fissured specimen all first decreased and then increased when the fissure angle increased from 0° to 75°. In order to investigate the crack initiation, propagation and coalescence process, photographic monitoring was adopted to capture images during the entire deformation process. Moreover, acoustic emission (AE) monitoring technique was also used to obtain the AE evolution characteristic of pre-fissured specimen. The relationship between axial stress, AE events, and the crack coalescence process was set up: when a new crack was initiated or a crack coalescence occurred, the corresponding axial stress dropped in the axial stress-time curve and a big AE event could be observed simultaneously. Finally, the mechanism of crack propagation under microscopic observation was discussed. These experimental results are expected to increase the understanding of the strength failure behavior and the cracking mechanism of rock containing unparallel fissures.

  14. Pulmonary Fissure Detection in CT Images Using a Derivative of Stick Filter.

    PubMed

    Xiao, Changyan; Stoel, Berend C; Bakker, M Els; Peng, Yuanyuan; Stolk, Jan; Staring, Marius

    2016-06-01

    Pulmonary fissures are important landmarks for recognition of lung anatomy. In CT images, automatic detection of fissures is complicated by factors like intensity variability, pathological deformation and imaging noise. To circumvent this problem, we propose a derivative of stick (DoS) filter for fissure enhancement and a post-processing pipeline for subsequent segmentation. Considering a typical thin curvilinear shape of fissure profiles inside 2D cross-sections, the DoS filter is presented by first defining nonlinear derivatives along a triple stick kernel in varying directions. Then, to accommodate pathological abnormality and orientational deviation, a [Formula: see text] cascading and multiple plane integration scheme is adopted to form a shape-tuned likelihood for 3D surface patches discrimination. During the post-processing stage, our main contribution is to isolate the fissure patches from adhering clutters by introducing a branch-point removal algorithm, and a multi-threshold merging framework is employed to compensate for local intensity inhomogeneity. The performance of our method was validated in experiments with two clinical CT data sets including 55 publicly available LOLA11 scans as well as separate left and right lung images from 23 GLUCOLD scans of COPD patients. Compared with manually delineating interlobar boundary references, our method obtained a high segmentation accuracy with median F1-scores of 0.833, 0.885, and 0.856 for the LOLA11, left and right lung images respectively, whereas the corresponding indices for a conventional Wiemker filtering method were 0.687, 0.853, and 0.841. The good performance of our proposed method was also verified by visual inspection and demonstration on abnormal and pathological cases, where typical deformations were robustly detected together with normal fissures. PMID:26766371

  15. The effect of CT technical factors on quantification of lung fissure integrity

    NASA Astrophysics Data System (ADS)

    Chong, D.; Brown, M. S.; Ochs, R.; Abtin, F.; Brown, M.; Ordookhani, A.; Shaw, G.; Kim, H. J.; Gjertson, D.; Goldin, J. G.

    2009-02-01

    A new emphysema treatment uses endobronchial valves to perform lobar volume reduction. The degree of fissure completeness may predict treatment efficacy. This study investigated the behavior of a semiautomated algorithm for quantifying lung fissure integrity in CT with respect to reconstruction kernel and dose. Raw CT data was obtained for six asymptomatic patients from a high-risk population for lung cancer. The patients were scanned on either a Siemens Sensation 16 or 64, using a low-dose protocol of 120 kVp, 25 mAs. Images were reconstructed using kernels ranging from smooth to sharp (B10f, B30f, B50f, B70f). Research software was used to simulate an even lower-dose acquisition of 15 mAs, and images were generated at the same kernels resulting in 8 series per patient. The left major fissure was manually contoured axially at regular intervals, yielding 37 contours across all patients. These contours were read into an image analysis and pattern classification system which computed a Fissure Integrity Score (FIS) for each kernel and dose. FIS values were analyzed using a mixed-effects model with kernel and dose as fixed effects and patient as random effect to test for difference due to kernel and dose. Analysis revealed no difference in FIS between the smooth kernels (B10f, B30f) nor between sharp kernels (B50f, B70f), but there was a significant difference between the sharp and smooth groups (p = 0.020). There was no significant difference in FIS between the two low-dose reconstructions (p = 0.882). Using a cutoff of 90%, the number of incomplete fissures increased from 5 to 10 when the imaging protocol changed from B50f to B30f. Reconstruction kernel has a significant effect on quantification of fissure integrity in CT. This has potential implications when selecting patients for endobronchial valve therapy.

  16. A novel method of anal fissure laser surgery: a pilot study.

    PubMed

    Esfahani, Mehran Nasr; Madani, Golnoush; Madhkhan, Sepideh

    2015-08-01

    Anal fissure is a common painful problem, affecting all age groups. Its pathophysiology is based on high sphincter pressures and reduced blood supplying and treatments which means that it generally reduces anal pressures and increases anodermal blood flow. Since each of the anal fissure's routine therapies has some limitations such as definite risk of permanent fecal incontinence and high recurrence rate, we tried to find a more effective and less invasive procedure. In this pilot study which was implemented on 25 male and female patients aged 20-75 years, diagnosed clinically with chronic anal fissure, the Carbon Dioxide Laser Fractional was used to treat patients. In order to first remove fibrotic and granulation tissues, the base and the edges of the fissure were laser beamed. Eight spots were made on the sphincter by the laser on its continuous mode; somehow, they were passed through the full thickness of sphincter without interrupting its continuance. Afterwards, the area around the fissure ulcer was irradiated by deep fractional mode of the laser to stimulate the submucosa to regenerate and rejuvenate. After going through this procedure, patients were followed up within 6 months to 1 year. Pain, bleeding, and constipation were significantly improved. None of the patients had recurrence after a 1-year follow-up, and none of them had fecal incontinence and/or inability to control the passage of gas too. This study revealed that this new laser-based surgery is a simple, safe, and effective procedure to treat the anal fissure that can be performed with local anesthesia in an outpatient clinic with minimal postoperative morbidity. PMID:26067925

  17. Processes and interactions in macrofaunal assemblages at hydrothermal vents: A modeling perspective

    NASA Astrophysics Data System (ADS)

    Shea, Katriona; Metaxas, Anna; Young, Curtis R.; Fisher, Charles R.

    Our understanding of the biological assemblages at hydrothermal vents is growing rapidly, in part facilitated by the coupling of experimental and observational methods with theoretical modeling efforts. We review theoretical approaches in four main areas and link them to empirical studies of the biology of hydrothermal vent systems. First, we describe models of dispersal of vent organisms within and among vent sites. These models fall broadly into two categories: those based on larval biology and currents that predict dispersal capabilities from a source, and those using genetic data to address historical genetic links between populations. Then we discuss models for individual and population growth at a location and give examples from work in a biologically similar deep-sea environment: cold seeps. Third, we address how these two aspects can be integrated using models that couple dispersal and demography. Last, we summarize existing modeling approaches for community succession in other types of habitats, and outline the conceptual models and the sorts of data that currently exist for hydrothermal vent communities. Throughout, we also examine the use of models in improving experimental design.

  18. Safety Testing of Left Ventricular Vent Valves.

    PubMed

    Gavin, Caroline; Coblentz, John; Acsell, Jeffrey R; Shackelford, Anthony G; Sistino, Joseph J

    2015-03-01

    Vent vacuum relief valves (VRVs) are used to limit the negative pressure at the ventricular vent catheter tip as well as prevent reversal of blood flow and prevention of air embolism. The purpose of this study was to evaluate the performance of three commercially available ventricular vent valves. The negative pressure at which the vent valve opened was measured at the valve inlet using high-fidelity pressure transducers. Also, the flow rate at which air entrainment occurred due to valve opening was recorded. Using a 51.5 cm column of saline, the resistance for each valve was calculated. The mean ± SD opening negative pressures were -231.3 ± 35.2 mmHg for the Quest Medical valve, -219.8 mmHg ± 17.2 for the Sorin valve, and -329.6 · 38.0 mmHg for the Terumo valve. The red Quest Medical valve opened at a lower flow (1.44 ± .03 L/min) than the dark blue Sorin valve (2.93 ± .01 L/min) and light blue LH130 Terumo valve (2.36 ± .02 L/min). The Sorin valve had the least resistance of 34.1 dyn-s/cm, followed by the Terumo LH130 valve resistance of 58.1 dyn·s/cm5, and the Quest Medical VRV-II valve with a resistance of 66.5 dyn·s/cm. We found that the valves are significantly different in the negative pressure generated. Understanding the limitations of these devices is important to reduce the occurrence of adverse events associated with venting and to select the best device for a specific clinical application. PMID:26390676

  19. Double-porosity models for a fissured groundwater reservoir with fracture skin.

    USGS Publications Warehouse

    Moench, A.F.

    1984-01-01

    Theories of flow to a well in a double-porosity groundwater reservoir are modified to incorporate effects of a thin layer of low-permeability material or fracture skin that may be present at fracture-block interfaces as a result of mineral deposition or alteration. The commonly used theory for flow in double-porosity formations that is based upon the assumption of pseudo-steady state block-to-fissure flow is shown to be a special case of the theory presented in this paper. The latter is based on the assumption of transient block-to-fissure flow with fracture skin.-from Author

  20. An Unusual Stress Metabolite from a Hydrothermal Vent Fungus Aspergillus sp. WU 243 Induced by Cobalt.

    PubMed

    Ding, Chihong; Wu, Xiaodan; Auckloo, Bibi Nazia; Chen, Chen-Tung Arthur; Ye, Ying; Wang, Kuiwu; Wu, Bin

    2016-01-01

    A novel hybrid polyketide-terpenoid, aspergstressin (1), possessing a unique fused polycyclic structure, was induced from culture broth of strain Aspergillus sp. WU 243 by cobalt ion stimulation. The strain was isolated from the digestive gland of Xenograpsus testudinatus, a unique type of crab which dwells in the Kueishantao hydrothermal vents off Taiwan. The chemical structure and relative configuration of the stress metabolite were established by spectroscopic means. Aspergillus sp. WU 243 produced aspergstressin (1) only under cobalt stressed culture conditions. The results show that stress-driven discovery of new natural products from hydrothermal vent fungi is an effective strategy to unveil the untapped reservoir of small molecules from species found in the hydrothermal vent environment. PMID:26805789

  1. An Unusual Stress Metabolite from a Hydrothermal Vent Fungus Aspergillus sp. WU 243 Induced by Cobalt.

    PubMed

    Ding, Chihong; Wu, Xiaodan; Auckloo, Bibi Nazia; Chen, Chen-Tung Arthur; Ye, Ying; Wang, Kuiwu; Wu, Bin

    2016-01-01

    A novel hybrid polyketide-terpenoid, aspergstressin (1), possessing a unique fused polycyclic structure, was induced from culture broth of strain Aspergillus sp. WU 243 by cobalt ion stimulation. The strain was isolated from the digestive gland of Xenograpsus testudinatus, a unique type of crab which dwells in the Kueishantao hydrothermal vents off Taiwan. The chemical structure and relative configuration of the stress metabolite were established by spectroscopic means. Aspergillus sp. WU 243 produced aspergstressin (1) only under cobalt stressed culture conditions. The results show that stress-driven discovery of new natural products from hydrothermal vent fungi is an effective strategy to unveil the untapped reservoir of small molecules from species found in the hydrothermal vent environment. PMID:26784166

  2. 49 CFR 179.300-13 - Venting, loading and unloading valves.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 49 Transportation 3 2013-10-01 2013-10-01 false Venting, loading and unloading valves. 179.300-13..., loading and unloading valves. (a) Valves shall be of approved type, made of metal not subject to rapid deterioration by lading, and shall withstand tank test pressure without leakage. The valves shall be...

  3. 49 CFR 179.300-13 - Venting, loading and unloading valves.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 49 Transportation 3 2014-10-01 2014-10-01 false Venting, loading and unloading valves. 179.300-13..., loading and unloading valves. (a) Valves shall be of approved type, made of metal not subject to rapid deterioration by lading, and shall withstand tank test pressure without leakage. The valves shall be...

  4. 49 CFR 179.300-13 - Venting, loading and unloading valves.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 3 2011-10-01 2011-10-01 false Venting, loading and unloading valves. 179.300-13..., loading and unloading valves. (a) Valves shall be of approved type, made of metal not subject to rapid deterioration by lading, and shall withstand tank test pressure without leakage. The valves shall be...

  5. Ecology of deep-sea hydrothermal vent communities: A review

    SciTech Connect

    Lutz, R.A.; Kennish, M.J. )

    1993-08-01

    The present article reviews studies of the past 15 years of active and inactive hydrothermal vents. The focus of the discussion is on the ecology of the biological communities inhabiting hydrothermal vents. These communities exhibit high densities and biomass, low species diversity, rapid growth rates, and high metabolic rates. The authors attempt to relate the biology of hydrothermal vent systems to geology. Future directions for hydrothermal vent research are suggested. Since many vent populations are dependent on hydrothermal fluids and are consequently unstable, both short- and long-term aspects of the ecology of the vent organisms and the influence of chemical and geological factors on the biology of vent systems need to be established. 200 refs., 28 figs.

  6. Genetic susceptibility to dental caries on pit and fissure and smooth surfaces.

    PubMed

    Shaffer, J R; Wang, X; Desensi, R S; Wendell, S; Weyant, R J; Cuenco, K T; Crout, R; McNeil, D W; Marazita, M L

    2012-01-01

    Carious lesions are distributed nonuniformly across tooth surfaces of the complete dentition, suggesting that the effects of risk factors may be surface-specific. Whether genes differentially affect caries risk across tooth surfaces is unknown. We investigated the role of genetics on two classes of tooth surfaces, pit and fissure surfaces (PFS) and smooth surfaces (SMS), in more than 2,600 subjects from 740 families. Participants were examined for surface-level evidence of dental caries, and caries scores for permanent and/or primary teeth were generated separately for PFS and SMS. Heritability estimates (h(2), i.e. the proportion of trait variation due to genes) of PFS and SMS caries scores were obtained using likelihood methods. The genetic correlations between PFS and SMS caries scores were calculated to assess the degree to which traits covary due to common genetic effects. Overall, the heritability of caries scores was similar for PFS (h(2) = 19-53%; p < 0.001) and SMS (h(2) = 17-42%; p < 0.001). Heritability of caries scores for both PFS and SMS in the primary dentition was greater than in the permanent dentition and total dentition. With one exception, the genetic correlation between PFS and SMS caries scores was not significantly different from 100%, indicating that (mostly) common genes are involved in the risk of caries for both surface types. Genetic correlation for the primary dentition dfs (decay + filled surfaces) was significantly less than 100% (p < 0.001), indicating that genetic factors may exert differential effects on caries risk in PFS versus SMS in the primary dentition. PMID:22286298

  7. Effects of anterior cingulate fissurization on cognitive control during stroop interference.

    PubMed

    Huster, Rene J; Wolters, Carsten; Wollbrink, Andreas; Schweiger, Elisabeth; Wittling, Werner; Pantev, Christo; Junghofer, Markus

    2009-04-01

    The midcingulate cortex, as part of the more anteriorly located cingulate regions, is thought to play a major role in cognitive processes like conflict monitoring or response selection. Regarding midcingulate fissurization, the occurrence of a second or paracingulate sulcus is more common in the left than in the right hemisphere and has been shown to be associated with an advantageous performance on tests of executive functions. However, the cognitive mechanisms underlying such behavioral differences are completely unknown. The current study addressed this issue by comparing subjects with a low and a high degree of left hemispheric midcingulate fissurization while collecting behavioral as well as electrophysiological correlates of Stroop interference. A high degree of fissurization was associated with decreased behavioral Stroop interference accompanied by a stronger and prolonged frontal negative potential to incongruent trials starting around 320 ms. This increased frontal negativity is assumed to reflect an enhanced activity of a conflict monitoring system located in the midcingulate cortex. In contrast and starting around 400 ms, subjects with low fissurization revealed an increased positivity over parieto-occipital regions suggesting a compensatory need for enhanced effortful cognitive control in this group. These results contribute to the understanding of the neuronal implementation of individual differences regarding attentional mechanisms. PMID:18570202

  8. Identification of genetic loci underlying the kernel fissure-resistance exhibited by 'cypress' and 'saber'

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The economic value of broken rice is about half that of whole milled rice, so one goal of producers, millers, and rice breeders is to reduce broken grains that result from the dehusking and milling processes One of the primary causes of rice breakage is fissuring, or cracking, of the rice before it ...

  9. Giant desiccation fissures on the Black Rock and Smoke Creek Deserts, Nevada

    USGS Publications Warehouse

    Willden, R.; Mabey, D.R.

    1961-01-01

    Open fissures, from 100 to several hundred feet apart, that have produced polygonal patterns on the Black Rock Desert, Nevada, are believed to be giant desiccation cracks resulting from a secular trend toward aridity in the last few decades. Similar features on the Smoke Creek Desert probably have the same origin.

  10. Study of Operated Patients of Lateral Internal Anal Sphincterotomy for Chronic Anal Fissure

    PubMed Central

    Patel, Harshad Shankarlal; Chavda, Jagdish; Parikh, Jayesh; Naik, Nehal

    2013-01-01

    Introduction: Anal fissure causes significant morbidity in the population. It is proposed that elevated sphincter pressures may cause ischaemia of the anal lining and this may be responsible for the pain of anal fissures and their failure to heal. When pharmacologic therapy fails or fissures recur frequently, lateral internal sphincterotomy is the surgical treatment of choice. Material and Methods: Retrospective analysis was done of admitted and operated patients of anal fissure by lateral anal internal sphincterotomy either by open or closed technique between April 2010 and November 2011 in Gujarat Medical Education & Research Society Medical College, Sola, Ahmedabad, India. The follow-up data of all patients was evaluated for pain relief, recurrence, wound infection, incontinence to flatus or stool or both for a period of up to 6 months. Results: Wound infection rate was 10.3% in open method and 4.2% in closed method. Incontinence to flatus was 8.3% in closed method and 3.4% in open method. This was temporary and controlled within a 1 week. Incontinence to stool was 3.4% in open method which was temporary and controlled within 2 weeks while none in closed method. None of the patients in either group had come with recurrence within 6 months follow-up. Conclusion: Lateral anal internal sphincterotomy is safe regarding long term incontinence and effective regarding recurrence. PMID:24551659

  11. Influence of matrix diffusion and exchange reactions on radiocarbon ages in fissured carbonate aquifers

    SciTech Connect

    Maloszewski, P. ); Zuber, A. )

    1991-08-01

    The parallel fissure model coupled with the equation of diffusion into the matrix and with exchange reaction equations has been used to derive a simple formula for estimating the influence of matrix porosity and reaction parameters on the determination of radiocarbon ages in fissured carbonate rocks. Examples of evidently too great radiocarbon ages in carbonate formations, which are not explainable by models for the initial {sup 14}C corrections, can easily be explained by this formula. Parameters obtained for a chalk formation from a known multitracer experiment combined with a pumping test suggest a possibility of {sup 14}C ages more than three orders of magnitude greater than the ages which would be observed if the radiocarbon transport took place only in the mobile water in the fissures. It is shown that contrary to the solute movement on a small scale and with a variable input, the large-scale movement, characteristic for the {sup 14}C dating, does not necessarily require the knowledge of kinetic parameters, because they may be replaced by the distribution coefficient. Discordant tritium and {sup 14}C concentrations are commonly interpreted as a proof of mixing either in the aquifer or at the discharge site. For fissured carbonate formations, however, an alternative explanation is given by the derived model showing a considerable delay of {sup 14}C with respect to nonsorbable tracers.

  12. Mapping the fissure potential zones based on microtremor measurement in Denpasar City, Bali

    NASA Astrophysics Data System (ADS)

    Prabowo, U. N.; Marjiyono; Sismanto

    2016-01-01

    Denpasar City and its vicinity considered as the areas with excessive ground water exploitation and high earthquake intensity. These conditions will cause these area potential with land subsidence which is triggering ground fissures. This research aims are to mapping the fissures potential areas based on microtremor measurement in Denpasar City and its vicinity. Ground fissures will happen if the land subsidence occurs in the areas which have different bedrock height beneath its sedimentary layer. The height of bedrock is determined by reducing surface elevation with the sedimentary layer thickness. This sedimentary layer thickness obtained from microtremor measurement using HVSR method, and Shear wave velocity (VS) obtained from microtremor array measurement which is analyzed by Spatial Auto Correlation (SPAC) method. The result from HVSR method as well as Peak Ground Acceleration (PGA) value are then analyzed to get ground shear strain value, which is the soil surface strain and its effect when earthquake occurs. Based on the bedrock map, it can be estimated that the bedrock layer forms structure in the southern part of the research areas and the potential fissuring area due to the massive ground water exploitation is in the west Denpasar Subdistrict. In addition, based on the bedrock map and ground shear strain value which combined with Simple Additive Weight (SAW) method, there are two areas having Assuring potential, i.e west and south Denpasar Subdistricts.

  13. Radiating graben-fissure systems in the Ulfrun Regio area, Venus

    NASA Astrophysics Data System (ADS)

    Studd, D.; Ernst, R. E.; Samson, C.

    2011-09-01

    Radiating graben-fissure systems are common on Venus. Most are thought to be underlain by mafic dykes, fed by centrally-located magmatic centres. From previous work it has been shown that these magmatic plumbing systems can extend out up to 2000 km or more and that interaction between neighbouring systems can provide insight into the relative chronology of their magmatic centres. Systematic mapping of graben-fissure systems has potential as a tool for regional magmatic chronology and correlation on Venus. This methodology is applied to the Ulfrun Regio area (200-240°E, 0-25°N) where we mapped 47,000 graben and fissures. From these, 66 radiating systems comprised of 13,000 individual graben and fissures, and having radii of up to 2000 km have been identified, and are interpreted to be underlain by dyke swarms focussed on magmatic centres. Cross-cutting relationships among these systems and with the Hecate Chasma rift zone have been examined to provide a relative chronology for the magmatic centres. Two trends emerged: (a) an apparent younging from the southwest to northeast of the study area and (b) a cluster of older ages in the southwest, linked to the Atla Regio mantle plume.

  14. Tensions and Fissures: The Politics of Standardised Testing and Accountability in Ontario, 1995-2015

    ERIC Educational Resources Information Center

    Pinto, Laura Elizabeth

    2016-01-01

    While Ontario has received international accolades for its enactment of province-wide standardised testing upon the formation of the Education Quality and Accountability Office (EQAO), a closer look at provincial assessments over a 20-year span reveals successes as well as systemic tensions and fissures. The purpose of this paper is twofold.…

  15. Sparger system for MMH-helium vents

    NASA Astrophysics Data System (ADS)

    Rakow, A.

    1983-09-01

    Based on a calculated vent flow rate and MMH concentration, a TI-59 program was run to determine total sparger hole area for a given sparger inlet pressure. Hole diameter is determined from a mass transfer analysis in the holding tank to achieve complete capture of MMH. In addition, based on oxidation kinetics and vapor pressure data, MMh atmospheric concentrations are determined 2 ft above the holding tank.

  16. Sparger system for MMH-helium vents

    NASA Technical Reports Server (NTRS)

    Rakow, A.

    1983-01-01

    Based on a calculated vent flow rate and MMH concentration, a TI-59 program was run to determine total sparger hole area for a given sparger inlet pressure. Hole diameter is determined from a mass transfer analysis in the holding tank to achieve complete capture of MMH. In addition, based on oxidation kinetics and vapor pressure data, MMh atmospheric concentrations are determined 2 ft above the holding tank.

  17. Comparative Study of Vented vs. Unvented Crawlspaces

    SciTech Connect

    Biswas, Kaushik; Christian, Jeffrey E; Gehl, Anthony C

    2011-10-01

    There has been a significant amount of research in the area of building energy efficiency and durability. However, well-documented quantitative information on the impact of crawlspaces on the performance of residential structures is lacking. The objective of this study was to evaluate and compare the effects of two crawlspace strategies on the whole-house performance of a pair of houses in a mixed humid climate. These houses were built with advanced envelope systems to provide energy savings of 50% or more compared to traditional 2010 new construction. One crawlspace contains insulated walls and is sealed and semi-conditioned. The other is a traditional vented crawlspace with insulation in the crawlspace ceiling. The vented (traditional) crawlspace contains fiberglass batts installed in the floor chase cavities above the crawl, while the sealed and insulated crawlspace contains foil-faced polyisocyanurate foam insulation on the interior side of the masonry walls. Various sensors to measure temperatures, heat flux through crawlspace walls and ceiling, and relative humidity were installed in the two crawlspaces. Data from these sensors have been analyzed to compare the performance of the two crawlspace designs. The analysis results indicated that the sealed and insulated crawlspace design is better than the traditional vented crawlspace in the mixed humid climate.

  18. The effects of vent-notch area on bulging and thinning during the clad vent test closure-weld operation

    SciTech Connect

    Ulrich, G.B.

    1996-09-01

    The internal gas pressure during clad vent set (CVS) welding is vented through aligned vent notches in each cup. For Galileo, Ulysses, and most of Cassini CVS production, the vent-notch dimensional requirements for both cups were as follows: (1) vent-notch depth, 0.15/0.20 mm; (2) vent-notch width, 0.25/0.35 nun; (3) bottom of vent-notch comers, sharp to full radius; (4) top of vent-notch edge, 0.05 mm maximum break; and (5) maximum variation between vent notch and grit-blasted triangle centerlines, 3{degrees}. During the fuel encapsulation operation (with {sup 238}PuO{sub 2} fuel pellets) at Los Alamos National Laboratory (LANL), excessive bulges or blowouts at the CVS closure-weld tie-in location occurred with 11.8% (27 out of 229) of the flight-quality welds made with the aforementioned standard vent-notch dimensions. These bulges and blowouts are primarily the result of inadequate venting of the increased gas pressure during the thermal cycle of the closure-weld operation. Proper venting is dependent mostly upon the weld parameters and the total vent-notch area. Because of the increased incidence of bulges/blowouts in the {sup 238}PuO{sub 2}-fueled CVS units, LANL personnel requested that consideration be given to increasing the vent-notch size to minimize further the loss of CVS hardware and the potential loss of {sup 238}PuO{sub 2} pellets. Thus, increasing further the production yield of the closure-weld operation would avoid potentially severe schedule delays.

  19. Effects of menthol essence and breast milk on the improvement of nipple fissures in breastfeeding women

    PubMed Central

    Akbari, Sedigheh Amir Ali; Alamolhoda, Seideh Hanieh; Baghban, Alireza Akbarzadeh; Mirabi, Parvaneh

    2014-01-01

    Background: Nipple fissure is a common disorder during breastfeeding. With high prevalence of nipple fissures and its impacts on breastfeeding, as well as the existence of evidence in favor of the application of peppermint as an antiinflammatory and antiinfection herb, the purpose of this study is to determine the effect of Menthol essence on improving nipple fissures in the primiparous breastfeeding women. Materials and Methods: This study was conducted using a clinical trial method. Samples were divided randomly into two groups of 55 women. The women in the peppermint group applied four drops of Menthol essence on their nipple and areola after each feeding. The control group applied four drops of their own milk on the nipple and areola after each feeding. Then, the two groups were studied on days 10 and 14 postpartum. For intensity of pain, the visual analog scale (0-10 cm) and to measure the severity of damage, Amir scale (1-10 cm) were applied and the existence or lack of nipple discharge was also recorded. The data were analyzed using SPSS 17 software. Results: The mean intensity of pain and nipple fissure before treatment (8.55 ± 1.74) and day 10 after delivery (4.26 ± 1.57) and before treatment and day 14 after delivery in the case group (1.32 ± 1.02) had a significant difference (P < 0.001). Nipple discharge between the two groups, before treatment (%75.2) and day 10 after delivery (%31.6) and before treatment and day 14 after delivery (%15.7), the case group had a significant difference (P < 0.001). Conclusion: Menthol essence can improve nipple fissures in the primiparous breastfeeding women. PMID:25364362

  20. The biological deep sea hydrothermal vent as a model to study carbon dioxide capturing enzymes.

    PubMed

    Minic, Zoran; Thongbam, Premila D

    2011-01-01

    Deep sea hydrothermal vents are located along the mid-ocean ridge system, near volcanically active areas, where tectonic plates are moving away from each other. Sea water penetrates the fissures of the volcanic bed and is heated by magma. This heated sea water rises to the surface dissolving large amounts of minerals which provide a source of energy and nutrients to chemoautotrophic organisms. Although this environment is characterized by extreme conditions (high temperature, high pressure, chemical toxicity, acidic pH and absence of photosynthesis) a diversity of microorganisms and many animal species are specially adapted to this hostile environment. These organisms have developed a very efficient metabolism for the assimilation of inorganic CO₂ from the external environment. In order to develop technology for the capture of carbon dioxide to reduce greenhouse gases in the atmosphere, enzymes involved in CO₂ fixation and assimilation might be very useful. This review describes some current research concerning CO₂ fixation and assimilation in the deep sea environment and possible biotechnological application of enzymes for carbon dioxide capture. PMID:21673885

  1. The Biological Deep Sea Hydrothermal Vent as a Model to Study Carbon Dioxide Capturing Enzymes

    PubMed Central

    Minic, Zoran; Thongbam, Premila D.

    2011-01-01

    Deep sea hydrothermal vents are located along the mid-ocean ridge system, near volcanically active areas, where tectonic plates are moving away from each other. Sea water penetrates the fissures of the volcanic bed and is heated by magma. This heated sea water rises to the surface dissolving large amounts of minerals which provide a source of energy and nutrients to chemoautotrophic organisms. Although this environment is characterized by extreme conditions (high temperature, high pressure, chemical toxicity, acidic pH and absence of photosynthesis) a diversity of microorganisms and many animal species are specially adapted to this hostile environment. These organisms have developed a very efficient metabolism for the assimilation of inorganic CO2 from the external environment. In order to develop technology for the capture of carbon dioxide to reduce greenhouse gases in the atmosphere, enzymes involved in CO2 fixation and assimilation might be very useful. This review describes some current research concerning CO2 fixation and assimilation in the deep sea environment and possible biotechnological application of enzymes for carbon dioxide capture. PMID:21673885

  2. Post-eruption succession of macrofaunal communities at diffuse flow hydrothermal vents on Axial Volcano, Juan de Fuca Ridge, Northeast Pacific

    NASA Astrophysics Data System (ADS)

    Marcus, Jean; Tunnicliffe, Verena; Butterfield, David A.

    2009-09-01

    Hydrothermal vents harbor dense aggregations of invertebrate fauna supported by chemosynthesis. Severe tectonic events and volcanic eruptions frequently destroy vent communities and initiate primary succession at new vents on ridge-crest submarine lava flows. An eruption on Axial Volcano (˜1500 m depth), a seamount on the Juan de Fuca Ridge (JdFR) in the northeast Pacific Ocean, occurred in January 1998, which created new substratum and vents. This study examines the development of the macrofaunal vent assemblages associated with tubeworms ( Ridgeia piscesae) at eight diffuse flow vents over the following 3 years. Biological collections by suction of lava surfaces also characterized "pre-tubeworm assemblages". Coupled fluid sampling showed an overall decrease in temperature, sulphide, and sulphide-to-heat ratios over 3 years as well as large spatial variability across the new vents. We examined collections of pre-eruption diffuse flow vent assemblages at Axial Volcano to compare the stages of new community development to "mature" vents. Mature vent assemblages are characterized by two major community types dominated by limpets ( Lepetodrilus fucensis) and alvinellid polychaetes ( Paralvinella pandorae and/or P. palmiformis). The following post-eruption succession patterns emerged. First, R. piscesae tubeworms took up to 3 years to establish aggregations at the new vents, and the majority of pre-tubeworm assemblages were dominated by grazing polychaetes. Second, species colonized quickly and by 30 months after habitat creation >60% of Axial's species pool had arrived at the new vents; abundance at mature vents predicted colonization success with some notable exceptions. Third, shifts in species dominance occurred rapidly and by Year 3 new vent assemblages resembled mature, pre-eruption communities. In general, tubeworm assemblages were dominated by alvinellid polychaetes ( P. pandorae and P. palmiformis) in the first 2 years post-eruption, with limpets ( L

  3. Chemolithotrophic sulfur-oxidizing bacteria from the galapagos rift hydrothermal vents.

    PubMed

    Ruby, E G; Wirsen, C O; Jannasch, H W

    1981-08-01

    Three distinct physiological types of sulfur-oxidizing bacteria were enriched and isolated from samples collected at several deep-sea hydrothermal vents (2,550 m) of the Galapagos Rift ocean floor spreading center. Twelve strains of the obligately chemolithotrophic genus Thiomicrospira were obtained from venting water and from microbial mats covering surfaces in the immediate vicinity of the vents. From these and other sources two types of obligately heterotrophic sulfur oxidizers were repeatedly isolated that presumably oxidized thiosulfate either to sulfate (acid producing; 9 strains) or to polythionates (base producing; 74 strains). The former were thiobacilli-like, exhibiting a thiosulfate-stimulated increase in growth and CO(2) incorporation, whereas the latter were similar to previously encountered pseudomonad-like heterotrophs. The presence of chemolithotrophic sulfur-oxidizing bacteria in the sulfide-containing hydrothermal water supports the hypothesis that chemosynthesis provides a substantial primary food source for the rich populations of invertebrates found in the immediate vicinity of the vents. PMID:16345831

  4. Chemolithotrophic Sulfur-Oxidizing Bacteria from the Galapagos Rift Hydrothermal Vents

    PubMed Central

    Ruby, E. G.; Wirsen, C. O.; Jannasch, H. W.

    1981-01-01

    Three distinct physiological types of sulfur-oxidizing bacteria were enriched and isolated from samples collected at several deep-sea hydrothermal vents (2,550 m) of the Galapagos Rift ocean floor spreading center. Twelve strains of the obligately chemolithotrophic genus Thiomicrospira were obtained from venting water and from microbial mats covering surfaces in the immediate vicinity of the vents. From these and other sources two types of obligately heterotrophic sulfur oxidizers were repeatedly isolated that presumably oxidized thiosulfate either to sulfate (acid producing; 9 strains) or to polythionates (base producing; 74 strains). The former were thiobacilli-like, exhibiting a thiosulfate-stimulated increase in growth and CO2 incorporation, whereas the latter were similar to previously encountered pseudomonad-like heterotrophs. The presence of chemolithotrophic sulfur-oxidizing bacteria in the sulfide-containing hydrothermal water supports the hypothesis that chemosynthesis provides a substantial primary food source for the rich populations of invertebrates found in the immediate vicinity of the vents. Images PMID:16345831

  5. Effect of Local Crystallographic Texture on the Fissure Formation During Charpy Impact Testing of Low-Carbon Steel

    NASA Astrophysics Data System (ADS)

    Ghosh, Abhijit; Patra, Sudipta; Chatterjee, Arya; Chakrabarti, Debalay

    2016-06-01

    The severity of the formation of fissures (also known as splitting or delamination) on the fracture surface of Charpy impact-tested samples of a low-carbon steel has been found to increase with the decrease in finish rolling temperature [1093 K to 923 K (820 °C to 650 °C)]. Combined scanning electron microscopy and electron back-scattered diffraction study revealed that crystallographic texture was the prime factor responsible for the fissure formation. Through-thickness texture band composed of cube [Normal Direction (ND)║<001>] and gamma [ND║<111>] orientations developed during the inter-critical rolling treatment. Strain incompatibility between these two texture bands causes fissure cracking on the main fracture plane. A new approach based on the angle between {001} planes of neighboring crystals has been employed in order to estimate the `effective grain size,' which is used to determine the cleavage fracture stress on different planes of a sample. The severity of fissure formation was found to be directly related to the difference in cleavage fracture stress between the `main fracture plane' and `fissure plane.' Clustering of ferrite grains having cube texture promoted the fissure crack propagation along the transverse `fissure plane,' by increasing the `effective grain size' and decreasing the cleavage fracture stress on that plane.

  6. Effects of Vent Asymmetry on Steady and Unsteady Eruption Dynamics

    NASA Astrophysics Data System (ADS)

    Sim, S.; Ogden, D.

    2013-12-01

    Models of volcanic eruptions are typically based on symmetric vent and conduit geometries. However, in natural settings, these features are rarely perfectly symmetric. For example, the May 18, 1980 eruption of Mount St Helens (MSH) took place through a highly asymmetrical crater due to the preceding landslide and subsequent vent erosion. In supersonic, high-pressure eruptions, such as what may have occurred at MSH, vent and crater asymmetry can strongly affect the directionality of the eruption. Here we explore flow dynamics resulting from a supersonic, high-pressure eruption though an asymmetric volcanic vent and a symmetric vent using a both unsteady numerical simulations and semi-analytical steady-state models. Preliminary results from both methods suggest that asymmetric vent shape may provide a first-order effect on dynamics of the initial phases of explosive eruptions.

  7. Flashback flame arrester devices for fuel cargo tank vapor vents

    NASA Technical Reports Server (NTRS)

    Bjorklund, R. A.; Kushida, R. O.

    1981-01-01

    The flame quenching capability of four types of flame arresting devices suitable for installation on fuel cargo tank vents of marine transport vessels is evaluated. A single 30 mesh screen, a dual 20 mesh screen, a spiral wound crimped metal ribbon, and a packed bed of ballast rings were tested. Flame speed and flame penetration of the test arresters were determined. Eight fuels representative of bulk cargoes were tested. The test arresters quenched a minimum of three flashback flames from all eight fuels, with one exception: high speed ethylene flames penetrated the dual 20 mesh screen on three tests. The arresters withstood the sustained flame from a propane/air mixture for 30 minutes. None of the arresters withstood the sustained flame from an ethylene/air mixture for more than 7 minutes.

  8. Prevalence of Dental Caries and Fissure Sealants in a Portuguese Sample of Adolescents

    PubMed Central

    Veiga, Nélio J.; Pereira, Carlos M.; Ferreira, Paula C.; Correia, Ilidio J.

    2015-01-01

    Introduction The aims of this study were to assess the prevalence of dental caries and the DMFT index, as well as the distribution pattern of pit and fissure sealants on permanent teeth in a Portuguese sample of adolescents, and to assess whether the existing usage of sealants and socio-demographic factors are correlated to caries prevalence on the examined sample. Materials and Methods A cross-sectional study was designed with a sample of 447 adolescents aged 12 to 18 years old, attending a public school in Sátão, Portugal. A self-administered questionnaire with questions about oral health behaviours and socio-economic status was answered by adolescents in the classroom. Clinical examination of oral health status and assessment of fissure sealants were accomplished by only one trained member of the research team. Results We obtained a DMFT index of 3.32 (2.92), which indicates a moderate level of prevalence of dental caries. When considering a DMFT = 0, we found significant statistical differences between the parents´ level of education (≤ 4th grade = 26.3 vs 5th–12th grade = 18.8 vs <12th grade = 43.3, p = 0.001), gender (male = 27.3 vs female = 19.6, p = 0.04), age (≤15 years = 27.1 vs <15 years = 18.5, p = 0.02), presence of fissure sealants (yes = 30.6 vs no = 13.5, p = 0.001) and experience of dental pain (no = 25.4 vs yes = 16.8, p = 0.02). When analyzing the prevalence of fissure sealants, we verified that 58.8% of adolescents had at least one fissure sealant applied. Significant statistical differences were found when analyzing the presence of fissure sealants related with parents´educational level (<9th grade, OR = 1.56 CI95% = 1.05–2.54), gender (female, OR = 1.86 CI95% = 1.19–2.98), experience of dental pain (yes, OR = 0.62 CI95% = 0.39–0.97) and presence of dental caries (yes, OR = 0.35 CI95% = 0.19–0.65). Conclusions The moderate level of caries prevalence reveals the need of improvement of primary prevention interventions among

  9. King's Bowl Pit Crater, Lava Field and Eruptive Fissure, Idaho - A Multipurpose Volcanic Planetary Analog

    NASA Astrophysics Data System (ADS)

    Hughes, S. S.; Garry, B.; Kobs-Nawotniak, S. E.; Sears, D. W. G.; Borg, C.; Elphic, R. C.; Haberle, C. W.; Kobayashi, L.; Lim, D. S. S.; Sears, H.; Skok, J. R.; Heldmann, J. L.

    2014-12-01

    King's Bowl (KB) and its associated eruptive fissure and lava field on the eastern Snake River Plain, is being investigated by the NASA SSERVI FINESSE (Field Investigations to Enable Solar System Science and Exploration) team as a planetary analog to similar pits on the Moon, Mars and Vesta. The 2,220 ± 100 BP basaltic eruption in Craters of the Moon National Monument and Preserve represents early stages of low shield growth, which was aborted when magma supply was cut off. Compared to mature shields, KB is miniscule, with ~0.02 km3 of lava over ~3 km2, yet the ~6 km long series of fissures, cracks and pits are well-preserved for analog studies of volcanic processes. The termination of eruption was likely related to proximity of the 2,270 ± 50 BP eruption of the much larger Wapi lava field (~5.5 km3 over 325 km2 area) on the same rift. Our investigation extends early work by R. Greeley and colleagues, focusing on imagery, compositional variations, ejecta distribution, dGPS profiles and LiDAR scans of features related to: (1) fissure eruptions - spatter ramparts, cones, feeder dikes, extension cracks; (2) lava lake formation - surface morphology, squeeze-ups, slab pahoehoe lava mounds, lava drain-back, flow lobe overlaps; and (3) phreatic steam blasts - explosion pits, ejecta blankets of ash and blocks. Preliminary results indicate multiple fissure eruptions and growth of a basin-filled lava lake up to ~ 10 m thick with outflow sheet lava flows. Remnant mounds of original lake crust reveal an early high lava lake level, which subsided as much as 5 m as the molten interior drained back into the fissure system. Rapid loss of magma supply led to the collapse of fissure walls allowing groundwater influx that triggered multiple steam blasts along at least 500 m. Early blasts occurred while lake magma pressure was still high enough to produce squeeze-ups when penetrated by ejecta blocks. The King's Bowl pit crater exemplifies processes of a small, but highly energetic

  10. 46 CFR 153.353 - High velocity vents.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 5 2010-10-01 2010-10-01 false High velocity vents. 153.353 Section 153.353 Shipping... Systems § 153.353 High velocity vents. The discharge point of a B/3 or 4m venting system must be located..., unimpeded jet; (b) The jet has a minimum exit velocity of 30 m/sec (approx. 98.4 ft/sec); and (c) The...

  11. 46 CFR 153.353 - High velocity vents.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 5 2011-10-01 2011-10-01 false High velocity vents. 153.353 Section 153.353 Shipping... Systems § 153.353 High velocity vents. The discharge point of a B/3 or 4m venting system must be located..., unimpeded jet; (b) The jet has a minimum exit velocity of 30 m/sec (approx. 98.4 ft/sec); and (c) The...

  12. 46 CFR 153.352 - B/3 and 4 m venting system outlets.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 5 2010-10-01 2010-10-01 false B/3 and 4 m venting system outlets. 153.352 Section 153... Cargo Venting Systems § 153.352 B/3 and 4 m venting system outlets. A B/3 or 4 m venting system outlet must: (a) Discharge vertically upwards; and (b) Prevent precipitation from entering the vent system....

  13. Getting the bigger picture: Using precision Remotely Operated Vehicle (ROV) videography to acquire high-definition mosaic images of newly discovered hydrothermal vents in the Southern Ocean

    NASA Astrophysics Data System (ADS)

    Marsh, Leigh; Copley, Jonathan T.; Huvenne, Veerle A. I.; Tyler, Paul A.; Isis ROV Facility

    2013-08-01

    Direct visual observations from submersible vehicles at hydrothermal vents typically only reveal a fraction of the vent environment at any one time. We describe the use of precision Remotely Operated Vehicle (ROV) videography to produce extensive mosaic images of hydrothermal vent chimneys and surrounding seafloor areas (c. 250 m2), with sufficient resolution to determine distributions of macro- and megafauna. Doppler velocity log navigation (DVLNAV) was used to follow overlapping vertical survey lines in a fixed plane facing a vent chimney, while acquiring high-definition video imagery using a forward-looking camera. The DVLNAV also enabled the vehicle to follow overlapping horizontal survey lines while acquiring seafloor imagery from a downward-looking video camera and mapping variations in seawater temperature. Digital stills images extracted from video were used to compile high-resolution composite views of the surveyed areas. Applying these image acquisition techniques at vent fields on the East Scotia Ridge, Southern Ocean, revealed consistent patterns of faunal zonation around vent sources, variations in proportions of faunal assemblage types on different faces of a vent chimney, and differences in proportions of faunal assemblages between two different vent fields. The technique can therefore be used to determine the composition and spatial distribution of fauna across complex areas of topography, such as vent fields, where mosaic images of vertical structures cannot currently be acquired using other platforms such as autonomous underwater vehicles (AUVs). These image acquisition techniques, demonstrated here in the first ROV dives at newly discovered vent fields, may offer an appropriate technology for rapid baseline studies required by the potential mining of seafloor massive sulfides (SMS).

  14. Experimental investigation on influence of smoke venting velocity and vent height on mechanical smoke exhaust efficiency.

    PubMed

    Jie, Ji; Kaiyuan, Li; Wei, Zhong; Ran, Huo

    2010-05-15

    A set of burning experiments were conducted to investigate the influence of smoke vent height and exhausting velocity on mechanical smoke exhausting efficiency. Results have shown that the smoke exhausting process becomes more efficient due to the increased smoke vent height and the decreased exhausting velocity, which eliminate the plug-holing issue with fewer disturbances on the smoke layer interface. For each certain exhausting velocity, there is a critical value of distance between the vent and the bottom of the smoke layer. When the distance is less than the critical value, the smoke exhausting is inefficient, and the efficiency decreases sharply as the distance decreases. Contrarily, when the distance is greater than the critical value, a good efficiency can be acquired and the exhausted smoke increased relatively slowly as the distance increases. A critical Froude number, proposed by Hinkley to predict the onset of plug-holing effect in gravity venting systems, was validated in the experiments. However, the experimental results indicate that in the tests without the plug-holing, the fresh air entrained due to smoke exhausting is up to 48% of the mechanical exhausting rate. PMID:20042292

  15. 14 CFR 23.975 - Fuel tank vents and carburetor vapor vents.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... or level flight attitudes, unless drainage is provided. Any drain valve installed must be accessible... one tank and it is necessary to use these tanks in a definite sequence for any reason, the vapor vent... fuel during acrobatic maneuvers, including short periods of inverted flight, must be prevented. It...

  16. 14 CFR 23.975 - Fuel tank vents and carburetor vapor vents.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... or level flight attitudes, unless drainage is provided. Any drain valve installed must be accessible... one tank and it is necessary to use these tanks in a definite sequence for any reason, the vapor vent... fuel during acrobatic maneuvers, including short periods of inverted flight, must be prevented. It...

  17. 14 CFR 23.975 - Fuel tank vents and carburetor vapor vents.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... or level flight attitudes, unless drainage is provided. Any drain valve installed must be accessible... one tank and it is necessary to use these tanks in a definite sequence for any reason, the vapor vent... fuel during acrobatic maneuvers, including short periods of inverted flight, must be prevented. It...

  18. 14 CFR 23.975 - Fuel tank vents and carburetor vapor vents.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... or level flight attitudes, unless drainage is provided. Any drain valve installed must be accessible... one tank and it is necessary to use these tanks in a definite sequence for any reason, the vapor vent... fuel during acrobatic maneuvers, including short periods of inverted flight, must be prevented. It...

  19. Ground fissures in the area of Mavropigi Village (N. Greece): Seismotectonics or mining activity?

    NASA Astrophysics Data System (ADS)

    Kalogirou, Eleni; Tsapanos, Theodoros; Karakostas, Vassilios; Marinos, Vassilios; Chatzipetros, Alexandros

    2014-12-01

    In the beginning of July 2010, a ground fissure was observed in the field near the village of Mavropigi (Northern Greece) and specifically in its NW side. Later on (early September), a second ground fissure was perceived, close and almost parallel to the first one and very close to the limits of the lignite exploitation mine (by the Public Power Corporation, PPC). It was observed that the village of Mavropigi slides away slowly towards the PPC lignite mine. Geological, seismological, as well as geotechnical survey in the field indicated that the phenomenon is related to the coal mining exploitation in the near vicinity of the village rather than to any seismotectonic activity in the surrounding area.

  20. Artificial recharge through a well in fissured carbonate rock, west St. Paul, Minnesota

    USGS Publications Warehouse

    Reeder, Harold O.; Wood, Warren W.; Ehrlich, G.G.; Sun, Ren Jen

    1976-01-01

    The injection test demonstrated that it is hydrologically feasible to recharge the Prairie du Chien Group and the Jordan Sandstone artificially through wells completed in the Prairie du Chien Group. The fissures in the Prairie du Chien Group act as conduits through which water spreads. The water passes into the Jordan Sandstone from the Prairie du Chien over a larger area than it would if it were injected directly into the Jordan.

  1. Quality Assessment of Information About Pit and Fissure Sealants in Persian Websites in 2012

    PubMed Central

    Ghasemi, Leila

    2016-01-01

    Objectives: Despite the increasing use of Internet, there is no supervision over the accuracy and quality of the information provided in the web. To deal with this problem, health specialists should take part in planning, publishing and supervision of online health-related information. The aim of this study was to evaluate the quality of information related to pit and fissure sealants in Persian websites. Materials and Methods: In this cross-sectional study, Persian websites providing information about fissure sealants were found using Google search engine. The searched keywords according to the MeSH database were “patient education” and “fissure sealant”. After applying the exclusion criteria, 37 websites out of 500 initial links remained in the study. These websites were evaluated based on a researcher-made checklist. The validity and reliability of the checklist were evaluated and confirmed. Descriptive analysis was applied to report the results of our study using SPSS version 11.5. Results: The average score for the quality of information was 22.46 out of 38. The minimum scores were 16 and 30 and belonged to Pezeshkanemrooz.com and Asa85.blogfa.com , respectively. The results showed that 62.2% of the answers were scored 2–4 and 37.8% were scored 1; therefore, the overall quality of the published content was rated to be moderate for 62.2% and low for 37.8% of the websites. Conclusions: Overall, the quality of information related to fissure sealant provided in Persian websites was good; however, the information given was mostly incomplete and could be improved. The main problems were doubtful credibility and outdated information.

  2. The metallurgical integrity of the frit vent assembly diffusion bond

    NASA Astrophysics Data System (ADS)

    Ulrich, G. B.

    1994-06-01

    Iridium alloy clad vent sets (CVS's) are now being made by Energy Systems at the Oak Ridge Y-12 Plant. These CVS's are being made for the US Department of Energy's (NE-53) General Purpose Heat Source- Radioisotope Thermoelectric Generator (GPHS-RTG) program, which is to supply electrical power for the National Aeronautics and Space Administration's Cassini mission to Saturn. A GPHS-RTG has 72 CVS'. Each CVS encapsulates one (238)PuO2 fuel pellet. The helium gas produced from the alpha decay of the (238)Pu is vented through a nominal 0.45-mm-diam hole in the vent cup of each CVS. A frit vent assembly that is electron beam welded over the vent hole allows helium gas to escape but prevents plutonia fines from exiting. The metallurgical integrity of frit vent assemblies produced by Martin Marietta Energy Systems, Inc. (Energy Systems) were compared with those produced earlier by EG&G-Mound Applied Technology, Inc. (EG&G-MAT). Scanning electron microscope (SEM) photographs were taken (at magnifications of from 126x to 1,000x) of the starting frit vent powder and the diffusion-bonded powder in finished frit vent assemblies produced by Energy Systems and EG&G-MAT. Frit vent assemblies also were metallographically prepared and visually examined/photographed at magnifications of from 50x to 1,000x. The SEM and metallographic examinations of the particle-to-particle and particle-to-foil component diffusion bonds indicated that the Energy Systems-produced and EG&G-MAT-produced frit vent assemblies have comparable metallurgical integrity. Statistical analysis of the Energy Systems production data shows that the frit vent manufacturing yield is 91%.

  3. The metallurgical integrity of the frit vent assembly diffusion bond

    SciTech Connect

    Ulrich, G.B.

    1994-06-01

    Iridium alloy clad vent sets (CVSs) are now being made by Energy Systems at the Oak Ridge Y-12 Plant. These CVSs are being made for the US Department of Energy`s (NE-53) General Purpose Heat Source- Radioisotope Thermoelectric Generator (GPHS-RTG) program, which is to supply electrical power for the National Aeronautics and Space Administration`s Cassini mission to Saturn. A GPHS-RTG has 72 CVSs. Each CVS encapsulates one {sup 238}PuO{sub 2} fuel pellet. The helium gas produced from the alpha decay of the {sup 238}Pu is vented through a nominal 0.45-mm-diam hole in the vent cup of each CVS. A frit vent assembly that is electron beam welded over the vent hole allows helium gas to escape but prevents plutonia fines from exiting. The metallurgical integrity of frit vent assemblies produced by Martin Marietta Energy Systems, Inc. (Energy Systems) were compared with those produced earlier by EG&G-Mound Applied Technology, Inc. (EG&G-MAT). Scanning electron microscope (SEM) photographs were taken (at magnifications of from 126X to 1,000X) of the starting frit vent powder and the diffusion-bonded powder in finished frit vent assemblies produced by Energy Systems and EG&G-MAT. Frit vent assemblies also were metallographically prepared and visually examined/photographed at magnifications of from 50X to 1,000X. The SEM and metallographic examinations of the particle-to-particle and particle-to-foil component diffusion bonds indicated that the Energy Systems-produced and EG&G-MAT-produced frit vent assemblies have comparable metallurgical integrity. Statistical analysis of the Energy Systems production data shows that the frit vent manufacturing yield is 91%.

  4. Potential for aquifer compaction, land subsidence, and earth fissures in the Tucson basin, Pima County, Arizona

    USGS Publications Warehouse

    Anderson, S.R.

    1987-01-01

    In 1979 the U.S. Geological Survey, in cooperation with the city of Tucson, began an investigation of aquifer compaction and its effects in the Tucson basin, including the potential hazards of aquifer compaction and subsequent damage to engineered structures, roads, water supply systems, gaslines, and sewage systems. Groundwater is the main source of water for irrigation, public supply, and industry. Pumping has exceeded recharge for several decades, and declines in groundwater levels have occurred in parts of the basin. In places, water level declines have resulted in small amounts of aquifer compaction and land subsidence. Further water level declines in parts of the Tucson basin may result in large amounts of aquifer compaction and land subsidence. Differential land subsidence may, in places, be accompanied by the formation of earth fissures. Aquifer compaction, land subsidence, and earth fissures can damage or affect the functional capability of manmade features. Specifically, aquifer compaction may damage wells, fissures may damage engineered structures, and differential land subsidence may affect structures such as sewers and water-supply systems that are dependent on gravity for their operation. (USGS)

  5. An Experimental and Numerical Study on Cracking Behavior of Brittle Sandstone Containing Two Non-coplanar Fissures Under Uniaxial Compression

    NASA Astrophysics Data System (ADS)

    Yang, Sheng-Qi; Tian, Wen-Ling; Huang, Yan-Hua; Ranjith, P. G.; Ju, Yang

    2016-04-01

    To understand the fracture mechanism in all kinds of rock engineering, it is important to investigate the fracture evolution behavior of pre-fissured rock. In this research, we conducted uniaxial compression experiments to evaluate the influence of ligament angle on the strength, deformability, and fracture coalescence behavior of rectangular prismatic specimens (80 × 160 × 30 mm) of brittle sandstone containing two non-coplanar fissures. The experimental results show that the peak strength of sandstone containing two non-coplanar fissures depends on the ligament angle, but the elastic modulus is not closely related to the ligament angle. With the increase of ligament angle, the peak strength decreased at a ligament angle of 60°, before increasing up to our maximum ligament angle of 120°. Crack initiation, propagation, and coalescence were all observed and characterized from the inner and outer tips of pre-existing non-coplanar fissures using photographic monitoring. Based on the results, the sequence of crack evolution in sandstone containing two non-coplanar fissures was analyzed in detail. In order to fully understand the crack evolution mechanism of brittle sandstone, numerical simulations using PFC2D were performed for specimens containing two non-coplanar fissures under uniaxial compression. The results are in good agreement with the experimental results. By analyzing the stress field, the crack evolution mechanism in brittle sandstone containing two non-coplanar fissures under uniaxial compression is revealed. These experimental and numerical results are expected to improve the understanding of the unstable fracture mechanism of fissured rock engineering structures.

  6. Fracturing and Seismicity at the Prestahnúkur Fissure Swarm in the Ultra-Slowly Spreading Western Volcanic Zone, Iceland

    NASA Astrophysics Data System (ADS)

    Hjartardottir, A. R.; Hjaltadottir, S.; Einarsson, P.; Vogfjord, K. S.

    2014-12-01

    Extension across the mid-Atlantic plate boundary in south Iceland is taken up by two parallel zones, the Western and the Eastern Volcanic Zones. Spreading across the western zone is of the order of 1-7 mm/year, qualifying it as an ultra-slow rift. The Prestahnúkur fissure swarm in the Western Volcanic Zone offers an opportunity to study magma-tectonic interaction in an ultra-slow spreading setting. In this study, fractures and faults were mapped in detail from aerial photographs to determine the extent of the fissure swarm. The fissure swarm is about 60 km long and 10 km wide, although its extent to the south is uncertain due to its linkage with the adjacent Hengill fissure swarm. The fissure swarm has both open fractures, indicating postglacial activation, and normal faults with up to 45 m vertical offset. Hyaloclastite ridges („tindars"), produced by subglacial fissure eruptions during the Pleistocene, are found within the fissure swarm, as well as postglacial lava flows. Intermittent seismicity occurs in the area. Earthquakes during the last ~24 years were relocated to study their relation with the surface fractures. Relocation of these events indicate that some of the fractures seen on surface have been activated during these years. The small cumulative seismic moment and slow spreading measured by geodetic methods nevertheless show that no dike intrusions have occurred during this period. Pleistocene tindars and Holocene lavas are clear indications of magmatism, however. We therefore suggest that the Prestahnúkur fissure swarm is mainly formed by diking and rifting during rifting episodes, whereas small scale fracture movements can occur during inter-rifting periods. The present small-scale fracture movements may indicate lack of magma to drive dike intrusions.

  7. Geomicrobiology of deep-sea hydrothermal vents.

    PubMed

    Jannasch, H W; Mottl, M J

    1985-08-23

    During the cycling of seawater through the earth's crust along the mid-ocean ridge system, geothermal energy is transferred into chemical energy in the form of reduced inorganic compounds. These compounds are derived from the reaction of seawater with crustal rocks at high temperatures and are emitted from warm (vents at depths of 2000 to 3000 meters. Chemolithotrophic bacteria use these reduced chemical species as sources of energy for the reduction of carbon dioxide (assimilation) to organic carbon. These bacteria form the base of the food chain, which permits copious populations of certain specifically adapted invertebrates to grow in the immediate vicinity of the vents. Such highly prolific, although narrowly localized, deep-sea communities are thus maintained primarily by terrestrial rather than by solar energy. Reduced sulfur compounds appear to represent the major electron donors for aerobic microbial metabolism, but methane-, hydrogen-, iron-, and manganese-oxidizing bacteria have also been found. Methanogenic, sulfur-respiring, and extremely thermophilic isolates carry out anaerobic chemosynthesis. Bacteria grow most abundantly in the shallow crust where upwelling hot, reducing hydrothermal fluid mixes with downwelling cold, oxygenated seawater. The predominant production of biomass, however, is the result of symbiotic associations between chemolithotrophic bacteria and certain invertebrates, which have also been found as fossils in Cretaceous sulfide ores of ophiolite deposits. PMID:17841485

  8. MAVEN Contamination Venting and Outgassing Analysis

    NASA Technical Reports Server (NTRS)

    Petro, Elaine M.; Hughes, David W.; Secunda, Mark S.; Chen, Philip T.; Morrissey, James R.; Riegle, Catherine A.

    2014-01-01

    Mars Atmosphere and Volatile EvolutioN (MAVEN) is the first mission to focus its study on the Mars upper atmosphere. MAVEN will study the evolution of the Mars atmosphere and climate, by examining the conduit through which the atmosphere has to pass as it is lost to the upper atmosphere. An analysis was performed for the MAVEN mission to address two distinct concerns. The first goal of the analysis was to perform an outgassing study to determine where species outgassed from spacecraft materials would redistribute to and how much of the released material might accumulate on sensitive surfaces. The second portion of the analysis serves to predict what effect, if any, Mars atmospheric gases trapped within the spacecraft could have on instrument measurements when re-released through vents. The re-release of atmospheric gases is of interest to this mission because vented gases from a higher pressure spacecraft interior could bias instrument measurements of the Mars atmosphere depending on the flow rates and directions.

  9. Geomicrobiology of Deep-Sea Hydrothermal Vents

    NASA Astrophysics Data System (ADS)

    Jannasch, Holger W.; Mottl, Michael J.

    1985-08-01

    During the cycling of seawater through the earth's crust along the midocean ridge system, geothermal energy is transferred into chemical energy in the form of reduced inorganic compounds. These compounds are derived from the reaction of seawater with crustal rocks at high temperatures and are emitted from warm (<= 25 degrees C) and hot (~ 350 degrees C) submarine vents at depths of 2000 to 3000 meters. Chemolithotrophic bacteria use these reduced chemical species as sources of energy for the reduction of carbon dioxide (assimilation) to organic carbon. These bacteria form the base of the food chain, which permits copious populations of certain specifically adapted invertebrates to grow in the immediate vicinity of the vents. Such highly prolific, although narrowly localized, deep-sea communities are thus maintained primarily by terrestrial rather than by solar energy. Reduced sulfur compounds appear to represent the major electron donors for aerobic microbial metabolism, but methane-, hydrogen-, iron-, and manganese-oxidizing bacteria have also been found. Methanogenic, sulfur-respiring, and extremely thermophilic isolates carry out anaerobic chemosynthesis. Bacteria grow most abundantly in the shallow crust where upwelling hot, reducing hydrothermal fluid mixes with downwelling cold, oxygenated seawater. The predominant production of biomass, however, is the result of symbiotic associations between chemolithotrophic bacteria and certain invertebrates, which have also been found as fossils in Cretaceous sulfide ores of ophiolite deposits.

  10. Diffuse flow from hydrothermal vents. Doctoral thesis

    SciTech Connect

    Trivett, D.A.

    1991-08-01

    The effluent from a collection of diffuse hydrothermal vents was modelled to determine the fate of the source of flow under typical environmental conditions at seafloor spreading centers. A laboratory simulation was conducted to test an analytic model of diffuse plume rise. The results showed that diffuse plumes are likely to remain near the seafloor, with their maximum rise height scaled with the diameter of the source of diffuse flow. The entrainment of ambient seawater into these plumes is limited by the proximity to the seafloor, thus slowing the rate of dilution. The model of diffuse plume behaviour was used to guide the design and implementation of a scheme for monitoring the flow from diffuse hydrothermal vents in the ocean. A deployment of an array at the Southern Juan de Fuca Ridge yielded measurements of a variety of diffuse plume properties, including total heat output. Two distinct sources of hydrothermal flow were detected during the field deployment. The larger source was 1-1.5km north of the instrument array, and its energy output was 450 + or - 270MW. A smaller source was located 100m east of one instrument in the array. The energy output of the source was 12 + or - 8MW. The rise heights of the centerlines of these plumes were 45m and 10m, respectively.

  11. Hydrothermal venting of greenhouse gases triggering Early Jurassic global warming

    NASA Astrophysics Data System (ADS)

    Svensen, Henrik; Planke, Sverre; Chevallier, Luc; Malthe-Sørenssen, Anders; Corfu, Fernando; Jamtveit, Bjørn

    2007-04-01

    The climate change in the Toarcian (Early Jurassic) was characterized by a major perturbation of the global carbon cycle. The event lasted for approximately 200,000 years and was manifested by a global warming of ˜ 6 °C, anoxic conditions in the oceans, and extinction of marine species. The triggering mechanisms for the perturbation and environmental change are however strongly debated. Here, we present evidence for a rapid formation and transport of greenhouse gases from the deep sedimentary reservoirs in the Karoo Basin, South Africa. Magmatic sills were emplaced during the initial stages of formation of the Early Jurassic Karoo Large Igneous Province, and had a profound influence on the fate of light elements in the organic-rich sedimentary host rocks. Total organic carbon contents and vitrinite reflectivity data from contact aureoles around the sills show that organic carbon was lost from the country rocks during heating. We present data from a new type of geological structures, termed breccia pipes, rooted in the aureoles within the shale of the Western Karoo Basin. The breccia pipes are cylindrical structures up to 150 meters in diameter and are mainly comprised of brecciated and baked black shale. Thousands of breccia pipes were formed due to gas pressure build-up during metamorphism of the shales, resulting in venting of greenhouse gases to the Toarcian atmosphere. Mass balance calculations constrained by new aureole data show that up to 1800 Gt of CO 2 was formed from organic material in the western Karoo Basin. About 15 times this amount of CO 2 (27,400 Gt) may have formed in the entire basin during the intrusive event. U-Pb dating of zircons from a sill related to many of the pipes demonstrates that the magma was emplaced 182.5 ± 0.4 million years ago. This supports a causal relationship between the intrusive volcanism, the gas venting, and the Toarcian global warming.

  12. Where are the undiscovered hydrothermal vents on oceanic spreading ridges?

    NASA Astrophysics Data System (ADS)

    Beaulieu, Stace E.; Baker, Edward T.; German, Christopher R.

    2015-11-01

    In nearly four decades since the discovery of deep-sea vents, one-third of the length of global oceanic spreading ridges has been surveyed for hydrothermal activity. Active submarine vent fields are now known along the boundaries of 46 out of 52 recognized tectonic plates. Hydrothermal survey efforts over the most recent decade were sparked by national and commercial interests in the mineral resource potential of seafloor hydrothermal deposits, as well as by academic research. Here we incorporate recent data for back-arc spreading centers and ultraslow- and slow-spreading mid-ocean ridges (MORs) to revise a linear equation relating the frequency of vent fields along oceanic spreading ridges to spreading rate. We apply this equation globally to predict a total number of vent fields on spreading ridges, which suggests that ~900 vent fields remain to be discovered. Almost half of these undiscovered vent fields (comparable to the total of all vent fields discovered during 35 years of research) are likely to occur at MORs with full spreading rates less than 60 mm/yr. We then apply the equation regionally to predict where these hydrothermal vents may be discovered with respect to plate boundaries and national jurisdiction, with the majority expected to occur outside of states' exclusive economic zones. We hope that these predictions will prove useful to the community in the future, in helping to shape continuing ridge-crest exploration.

  13. 46 CFR 56.50-85 - Tank-vent piping.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... of the tanks to vent pipes. (2) Tanks having a comparatively small surface, such as fuel oil settling... closure device shall be situated so as not to damage these screens. (10) The diameter of each vent pipe... for water ballast tanks, and 21/2 inches nominal pipe size for fuel oil tanks, except that...

  14. An authoritative global database for active submarine hydrothermal vent fields

    NASA Astrophysics Data System (ADS)

    Beaulieu, Stace E.; Baker, Edward T.; German, Christopher R.; Maffei, Andrew

    2013-11-01

    The InterRidge Vents Database is available online as the authoritative reference for locations of active submarine hydrothermal vent fields. Here we describe the revision of the database to an open source content management system and conduct a meta-analysis of the global distribution of known active vent fields. The number of known active vent fields has almost doubled in the past decade (521 as of year 2009), with about half visually confirmed and others inferred active from physical and chemical clues. Although previously known mainly from mid-ocean ridges (MORs), active vent fields at MORs now comprise only half of the total known, with about a quarter each now known at volcanic arcs and back-arc spreading centers. Discoveries in arc and back-arc settings resulted in an increase in known vent fields within exclusive economic zones, consequently reducing the proportion known in high seas to one third. The increase in known vent fields reflects a number of factors, including increased national and commercial interests in seafloor hydrothermal deposits as mineral resources. The purpose of the database now extends beyond academic research and education and into marine policy and management, with at least 18% of known vent fields in areas granted or pending applications for mineral prospecting and 8% in marine protected areas.

  15. Automatic protective vent has fail-safe feature

    NASA Technical Reports Server (NTRS)

    Dameron, C. E.

    1966-01-01

    Delayed vent valve system in a mechanical backing pump in a vacuum system allows the pneumatic foreline valve to seal before the pump vent opens. The system is designed to be fail-safe and operate even though there is loss of electrical power.

  16. 46 CFR 153.463 - Vent system discharges.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... BULK LIQUID, LIQUEFIED GAS, OR COMPRESSED GAS HAZARDOUS MATERIALS Design and Equipment Special Requirements for Flammable Or Combustible Cargoes § 153.463 Vent system discharges. The discharge of a venting... to carry a flammable or combustible cargo; and (b) Table 1 requires the cargo to have a PV...

  17. 46 CFR 153.463 - Vent system discharges.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... BULK LIQUID, LIQUEFIED GAS, OR COMPRESSED GAS HAZARDOUS MATERIALS Design and Equipment Special Requirements for Flammable Or Combustible Cargoes § 153.463 Vent system discharges. The discharge of a venting... to carry a flammable or combustible cargo; and (b) Table 1 requires the cargo to have a PV...

  18. 46 CFR 153.463 - Vent system discharges.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... BULK LIQUID, LIQUEFIED GAS, OR COMPRESSED GAS HAZARDOUS MATERIALS Design and Equipment Special Requirements for Flammable Or Combustible Cargoes § 153.463 Vent system discharges. The discharge of a venting... to carry a flammable or combustible cargo; and (b) Table 1 requires the cargo to have a PV...

  19. 46 CFR 153.463 - Vent system discharges.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... BULK LIQUID, LIQUEFIED GAS, OR COMPRESSED GAS HAZARDOUS MATERIALS Design and Equipment Special Requirements for Flammable Or Combustible Cargoes § 153.463 Vent system discharges. The discharge of a venting... to carry a flammable or combustible cargo; and (b) Table 1 requires the cargo to have a PV...

  20. 46 CFR 153.463 - Vent system discharges.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... BULK LIQUID, LIQUEFIED GAS, OR COMPRESSED GAS HAZARDOUS MATERIALS Design and Equipment Special Requirements for Flammable Or Combustible Cargoes § 153.463 Vent system discharges. The discharge of a venting... to carry a flammable or combustible cargo; and (b) Table 1 requires the cargo to have a PV...

  1. Thermodynamic Vent System Test in a Low Earth Orbit Simulation

    NASA Technical Reports Server (NTRS)

    VanOverbeke, Thomas J.

    2004-01-01

    A thermodynamic vent system for a cryogenic nitrogen tank was tested in a vacuum chamber simulating oxygen storage in low earth orbit. The nitrogen tank was surrounded by a cryo-shroud at -40 F. The tank was insulated with two layers of multi-layer insulation. Heat transfer into cryogenic tanks causes phase change and increases tank pressure which must be controlled. A thermodynamic vent system was used to control pressure as the location of vapor is unknown in low gravity and direct venting would be wasteful. The thermodynamic vent system consists of a Joule-Thomson valve and heat exchanger installed on the inlet side of the tank mixer-pump. The combination is used to extract thermal energy from the tank fluid, reducing temperature and ullage pressure. The system was sized so that the tank mixer-pump operated a small fraction of the time to limit motor heating. Initially the mixer used sub-cooled liquid to cool the liquid-vapor interface inducing condensation and pressure reduction. Later, the thermodynamic vent system was used. Pressure cycles were performed until steady-state operation was demonstrated. Three test runs were conducted at tank fills of 97, 80, and 63 percent. Each test was begun with a boil-off test to determine heat transfer into the tank. The lower tank fills had time averaged vent rates very close to steady-state boil-off rates showing the thermodynamic vent system was nearly as efficient as direct venting in normal gravity.

  2. Deep-sea primary production at the Galapagos hydrothermal vents

    SciTech Connect

    Karl, D.M.; Wirsen, C.O.; Jannasch, H.W.

    1980-03-21

    Dense animal populations surrounding recently discovered hydrothermal vents at the Galapagos Rift sea-floor spreading center, 2550 meters deep, are probably sustained by microbial primary production. Energy in the form of geothermically reduced sulfur compounds emitted from the vents is liberated during oxidation and used for the reduction of carbon dioxide to organic matter by chemosynthetic bacteria.

  3. 40 CFR 63.1429 - Process vent monitoring requirements.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... bypass lines that could divert a process vent stream away from the combustion, recovery, or recapture... of a process vent that uses a combustion, recovery, or recapture device to comply with the process... requirements in § 63.1439(f). Approval shall be requested if the owner or operator: (1) Uses a...

  4. Hydrogen Vent Ground Umbilical Quick Disconnect - Flight Seal Advanced Development

    NASA Technical Reports Server (NTRS)

    Girard, Doug; Jankowski, Fred; Minich, Mark C.; Yu, Weiping

    2012-01-01

    This project is a team effort between NASA Engineering (NE) and Team QNA Engineering personnel to provide support for the Umbilical Systems Development project which is funded by Advanced Exploration Systems (AES) and 21st Century Launch Complex. Specifically, this project seeks to develop a new interface between the PPBE baselined Legacy SSP LH2 Vent Arm QD probe and SLS vent seal.

  5. Device damps fluid pressure oscillations in vent valve

    NASA Technical Reports Server (NTRS)

    Nein, H. J.

    1968-01-01

    Device, containing a tuned series arrangement of two plenum chambers and two orifices, damps high pressure fluid oscillations in a vent valve. Used in conjunction with vent valves, it relieves gas pressure that develops in liquid hydrogen and liquid oxygen tanks used on a space vehicle.

  6. Convection venting lensed reflector-type compact fluorescent lamp system

    DOEpatents

    Pelton, Bruce A.; Siminovitch, Michael

    1997-01-01

    Disclosed herein is a fluorescent lamp housing assembly capable of providing convection cooling to the lamp and the ballast. The lens of the present invention includes two distinct portions, a central portion and an apertured portion. The housing assembly further includes apertures so that air mass is able to freely move up through the assembly and out ventilation apertures.

  7. Convection venting lensed reflector-type compact fluorescent lamp system

    DOEpatents

    Pelton, B.A.; Siminovitch, M.

    1997-07-29

    Disclosed herein is a fluorescent lamp housing assembly capable of providing convection cooling to the lamp and the ballast. The lens of the present invention includes two distinct portions, a central portion and an apertured portion. The housing assembly further includes apertures so that air mass is able to freely move up through the assembly and out ventilation apertures. 12 figs.

  8. Feasibility and Safety Assessment for Advanced Reactor Concepts Using Vented Fuel

    SciTech Connect

    Klein, Andrew; Matthews, Topher; Lenhof, Renae; Deason, Wesley; Harter, Jackson

    2015-01-16

    Recent interest in fast reactor technology has led to renewed analysis of past reactor concepts such as Gas Fast Reactors and Sodium Fast Reactors. In an effort to make these reactors more economic, the fuel is required to stay in the reactor for extended periods of time; the longer the fuel stays within the core, the more fertile material is converted into usable fissile material. However, as burnup of the fuel-rod increases, so does the internal pressure buildup due to gaseous fission products. In order to reach the 30 year lifetime requirements of some reactor designs, the fuel pins must have a vented-type design to allow the buildup of fission products to escape. The present work aims to progress the understanding of the feasibility and safety issues related to gas reactors that incorporate vented fuel. The work was separated into three different work-scopes: 1. Quantitatively determine fission gas release from uranium carbide in a representative helium cooled fast reactor; 2. Model the fission gas behavior, transport, and collection in a Fission Product Vent System; and, 3. Perform a safety analysis of the Fission Product Vent System. Each task relied on results from the previous task, culminating in a limited scope Probabilistic Risk Assessment (PRA) of the Fission Product Vent System. Within each task, many key parameters lack the fidelity needed for comprehensive or accurate analysis. In the process of completing each task, the data or methods that were lacking were identified and compiled in a Gap Analysis included at the end of the report.

  9. Assessment of Literature Related to Combustion Appliance Venting Systems

    SciTech Connect

    Rapp, V. H.; Less, B. D.; Singer, B. C.; Stratton, J. C.; Wray, C. P.

    2015-02-01

    In many residential building retrofit programs, air tightening to increase energy efficiency is often constrained by safety concerns with naturally vented combustion appliances. Tighter residential buildings more readily depressurize when exhaust equipment is operated, making combustion appliances more prone to backdraft or spill combustion exhaust into the living space. Several measures, such as installation guidelines, vent sizing codes, and combustion safety diagnostics, are in place with the intent to prevent backdrafting and combustion spillage, but the diagnostics conflict and the risk mitigation objective is inconsistent. This literature review summarizes the metrics and diagnostics used to assess combustion safety, documents their technical basis, and investigates their risk mitigations. It compiles information from the following: codes for combustion appliance venting and installation; standards and guidelines for combustion safety diagnostics; research evaluating combustion safety diagnostics; research investigating wind effects on building depressurization and venting; and software for simulating vent system performance.

  10. Trophic regions of a hydrothermal plume dispersing away from an ultramafic-hosted vent-system: Von Damm vent-site, Mid-Cayman Rise

    NASA Astrophysics Data System (ADS)

    Bennett, Sarah A.; Coleman, Max; Huber, Julie A.; Reddington, Emily; Kinsey, James C.; McIntyre, Cameron; Seewald, Jeffrey S.; German, Christopher R.

    2013-02-01

    type</span>="main">Abstract Deep-sea ultramafic-hosted <span class="hlt">vent</span> systems have the potential to provide large amounts of metabolic energy to both autotrophic and heterotrophic microorganisms in their dispersing hydrothermal plumes. Such <span class="hlt">vent</span>-systems release large quantities of hydrogen and methane to the water column, both of which can be exploited by autotrophic microorganisms. Carbon cycling in these hydrothermal plumes may, therefore, have an important influence on open-ocean biogeochemistry. In this study, we investigated an ultramafic-hosted system on the Mid-Cayman Rise, emitting metal-poor and hydrogen sulfide-, methane-, and hydrogen-rich hydrothermal fluids. Total organic carbon concentrations in the plume ranged between 42.1 and 51.1 μM (background = 43.2 ± 0.7 μM (n = 5)) and near-field plume samples with elevated methane concentrations imply the presence of chemoautotrophic primary production and in particular methanotrophy. In parts of the plume characterized by persistent potential temperature anomalies but lacking elevated methane concentrations, we found elevated organic carbon concentrations of up to 51.1 μM, most likely resulting from the presence of heterotrophic communities, their extracellular products and <span class="hlt">vent</span> larvae. Elevated carbon concentrations up to 47.4 μM were detected even in far-field plume samples. Within the Von Damm hydrothermal plume, we have used our data to hypothesize a microbial food web in which chemoautotrophy supports a heterotrophic community of microorganisms. Such an active microbial food web would provide a source of labile organic carbon to the deep ocean that should be considered in any future studies evaluating sources and sinks of carbon from hydrothermal <span class="hlt">venting</span> to the deep ocean.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015IzAOP..51..667F','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015IzAOP..51..667F"><span id="translatedtitle">Seismic processes and migration of magma during the Great Tolbachik <span class="hlt">Fissure</span> Eruption of 1975-1976 and Tolbachik <span class="hlt">Fissure</span> Eruption of 2012-2013, Kamchatka Peninsula</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Fedotov, S. A.; Slavina, L. B.; Senyukov, S. L.; Kuchay, M. S.</p> <p>2015-12-01</p> <p>Seismic and volcanic processes in the area of the northern group of volcanoes (NGV) in Kamchatka Peninsula that accompanied the Great Tolbachik <span class="hlt">Fissure</span> Eruption (GTFE) of 1975-1976 and the Tolbachik <span class="hlt">Fissure</span> Eruption (TFE, or "50 let IViS" due to anniversary of the Institute of Volcanology and Seismology, Far East Branch, Russian Academy of Sciences) of 2012-2013 and the seismic activity between these events are considered. The features of evolution of seismic processes of the major NGV volcanoes (Ploskii Tolbachik, Klyuchevskoy, Bezymannyi, and Shiveluch) are revealed. The distribution of earthquakes along depth, their spatial and temporal migration, and the relation of seismic and volcanic activity are discussed. The major features of seismic activity during the GTFE preparation and evolution and a development of earthquake series preceding the origin of the northern and southern breaks are described. The character of seismic activity between the GTFE and TFE is shown. The major peculiarities of evolution of seismic activity preceding and accompanying the TFE are described. The major magma sources and conduits of the NGV volcanoes are identified, as is the existence of a main conduit in the mantle and a common intermediate source for the entire NGV, the depth of which is 25-35 km according to seismic data. The depth of a neutral buoyancy layer below the NGV is 15-20 km and the source of areal volcanism of magnesian basalts northeast of the Klyuchevskoy volcano is located at depth of ~20 km. These data support the major properties of a 2010 geophysical model of magmatic feeding system of the Klyuchevskoy group of volcanoes. The present paper covers a wider NGV area and is based on the real experimental observations.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20080047210','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20080047210"><span id="translatedtitle">Deep-Sea Hydrothermal-<span class="hlt">Vent</span> Sampler</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Behar, Alberto E.; Venkateswaran, Kasthur; Matthews, Jaret B.</p> <p>2008-01-01</p> <p>An apparatus is being developed for sampling water for signs of microbial life in an ocean hydrothermal <span class="hlt">vent</span> at a depth of as much as 6.5 km. Heretofore, evidence of microbial life in deep-sea hydrothermal <span class="hlt">vents</span> has been elusive and difficult to validate. Because of the extreme conditions in these environments (high pressures and temperatures often in excess of 300 C), deep-sea hydrothermal- <span class="hlt">vent</span> samplers must be robust. Because of the presumed low density of biomass of these environments, samplers must be capable of collecting water samples of significant volume. It is also essential to prevent contamination of samples by microbes entrained from surrounding waters. Prior to the development of the present apparatus, no sampling device was capable of satisfying these requirements. The apparatus (see figure) includes an intake equipped with a temperature probe, plus several other temperature probes located away from the intake. The readings from the temperature probes are utilized in conjunction with readings from flowmeters to determine the position of the intake relative to the hydrothermal plume and, thereby, to position the intake to sample directly from the plume. Because it is necessary to collect large samples of water in order to obtain sufficient microbial biomass but it is not practical to retain all the water from the samples, four filter arrays are used to concentrate the microbial biomass (which is assumed to consist of particles larger than 0.2 m) into smaller volumes. The apparatus can collect multiple samples per dive and is designed to process a total volume of 10 L of <span class="hlt">vent</span> fluid, of which most passes through the filters, leaving a total possibly-microbe-containing sample volume of 200 mL remaining in filters. A rigid titanium nose at the intake is used for cooling the sample water before it enters a flexible inlet hose connected to a pump. As the water passes through the titanium nose, it must be cooled to a temperature that is above a mineral</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015DPS....4741003M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015DPS....4741003M"><span id="translatedtitle"><span class="hlt">Venting</span> of CO2 at Enceladus’ Surface</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Matson, Dennis L.; Davies, Ashley G.; Johnson, Torrence V.; Combe, Jean-Philippe; McCord, Tom B.; Radebaugh, Jani</p> <p>2015-11-01</p> <p>Enceladus has CO2 surface deposits in its South Polar Region that have been recently mapped by J.-P. Combe et al. (2015 AGU Fall Meeting). Assuming that these are CO2 frost, we show how they can be formed. We use an ocean-water circulation model [1] that specifies pressure gradients that drive water to the surface from a relatively gas-rich, subsurface ocean. We now examine the movement of CO2 to the surface; formation of shallow CO2 gas pockets in the ice; and the <span class="hlt">venting</span> of CO2, when at least some of the gas freezes to form frost. If the local heat flow is known (cf. [2]), then the depths of the corresponding gas pockets can be calculated. References: [1] Matson et al. (2012) Icarus, 221, 53-62. [2] Howett et al. (2011) J. Geophys. Res. 116, E03003. Acknowledgements: AGD thanks the NASA OPR Program for support.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19730009838','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19730009838"><span id="translatedtitle">Design improvement, qualification testing, purge and <span class="hlt">vent</span> investigation, fabrication, and documentation of a GAC-9 insulation system</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Shriver, C. B.; Apisa, J. N.; Kariotis, A. H.</p> <p>1971-01-01</p> <p>Results of the research and development program to determine the purge and <span class="hlt">vent</span> characteristics of the GAC-9 insulation system are summarized. The work scope comprised: (1) literature survey; (2) design improvement and insulation effort; (3) testing; and (4) evaluation of test results. Program objectives to be realized are: (1) definition of purge gas flow characteristics of the GAC-9 insulation system through laboratory measurements; and (2) demonstration of insulation effectiveness as a system for prelaunch purging and launch <span class="hlt">venting</span> of the 76-cm diameter calorimeter, which is a subscale model simulating a realistic <span class="hlt">type</span> of GAC-9 insulation application.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012AGUFM.V21A2750K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012AGUFM.V21A2750K"><span id="translatedtitle">1891 Submarine eruption of Foerstner volcano (Pantelleria, Sicily) : insights into the <span class="hlt">vent</span> structure of basaltic balloon eruptions</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kelly, J. T.; Carey, S.; Bell, K. L.; Rosi, M.; Marani, M.; Roman, C.; Pistolesi, M.; Baker, E. T.</p> <p>2012-12-01</p> <p> second, previously unknown <span class="hlt">vent</span> located north of Foerstner volcano at a depth of around 350 meters. Given the close proximity of these two <span class="hlt">vents</span>, the differences in deposit <span class="hlt">types</span> may be due to changing eruption style as a function of water depth. The abundant pillow flow lobes observed at the northern <span class="hlt">vent</span> are most likely the result of more effusive eruptions occurring in deeper water (350 m) whereas the dominantly fragmental nature of material in the main southern <span class="hlt">vent</span> indicates more vigorous explosive activity at shallower levels (250 m). Based on the nature of deposits found at the <span class="hlt">vent</span> areas, the basaltic balloons of the 1891 Foerstner eruption are suspected to be a result of both coarse, localized fire fountaining activity and detachment from gas-charged flow lobes. The larger and shallower southern <span class="hlt">vent</span> area is likely to have been the main source of the basaltic balloons observed on the surface during the 1891 eruption. A review of other historic eruptions that have produced basaltic balloons suggests that this style of activity is likely to be restricted to a rather narrow range of water depths and thus recognition of the distinct deposits produced by this <span class="hlt">type</span> of activity in ancient deposits could help place important paleodepth constraints on volcaniclastic sequences.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016HydJ...24..649C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016HydJ...24..649C"><span id="translatedtitle">Land subsidence and earth <span class="hlt">fissures</span> in south-central and southern Arizona, USA</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Conway, Brian D.</p> <p>2016-05-01</p> <p>Land subsidence due to groundwater overdraft has been an ongoing problem in south-central and southern Arizona (USA) since the 1940s. The first earth <span class="hlt">fissure</span> attributed to excessive groundwater withdrawal was discovered in the early 1950s near Picacho. In some areas of the state, groundwater-level declines of more than 150 m have resulted in extensive land subsidence and earth <span class="hlt">fissuring</span>. Land subsidence in excess of 5.7 m has been documented in both western metropolitan Phoenix and Eloy. The Arizona Department of Water Resources (ADWR) has been monitoring land subsidence since 2002 using interferometric synthetic aperture radar (InSAR) and since 1998 using a global navigation satellite system (GNSS). The ADWR InSAR program has identified more than 25 individual land subsidence features that cover an area of more than 7,300 km2. Using InSAR data in conjunction with groundwater-level datasets, ADWR is able to monitor land subsidence areas as well as identify areas that may require additional monitoring. One area of particular concern is the Willcox groundwater basin in southeastern Arizona, which is the focus of this paper. The area is experiencing rapid groundwater declines, as much as 32.1 m during 2005-2014 (the largest land subsidence rate in Arizona State—up to 12 cm/year), and a large number of earth <span class="hlt">fissures</span>. The declining groundwater levels in Arizona are a challenge for both future groundwater availability and mitigating land subsidence associated with these declines. ADWR's InSAR program will continue to be a critical tool for monitoring land subsidence due to excessive groundwater withdrawal.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4890055','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4890055"><span id="translatedtitle">Ability of Pit and <span class="hlt">Fissure</span> Sealant-containing Amorphous Calcium Phosphate to inhibit Enamel Demineralization</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Owais, Arwa I; Kawaja, Wasan</p> <p>2016-01-01</p> <p>ABSTRACT Aim: To evaluate the effect of amorphous calcium phosphate (ACP)-containing pit and <span class="hlt">fissure</span> sealant on inhibition of enamel demineralization in vitro. Materials and methods: Enamel specimens (n = 75) were prepared using freshly extracted noncarious human third molars. Box-shaped cavities (8 × 2 × 2 mm) on the buccal or lingual surfaces were prepared and restored with resin-based sealant (Concise™), ACP-containing sealant (Aegis®) or fluoride-containing sealant (Conseal-F™). The samples were acid challenged in a demineralizing solution of 50 mmol/l lactic acid at pH 5.0 for 4 days. The change in enamel microhardness (ASuH) was calculated. Data were analyzed using one-way analysis of variance (ANOVA) and Tukey’s post hoc test. Results: The mean SuH0 (±SD) (in Vicker’s unit) prior to the acid challenge was: Concise™ (318.83 ± 33.86), Aegis® (331.03 ± 21.52), Conseal-F™ (310.12 ± 34.31). Following the acid challenge, the values dropped in all groups and ASuH (±SD) values were 269.17 ± 47.49, 151.39 ± 23.96 and 175.79 ± 32.39 respectively. Conclusion: The ACP-containing pit and <span class="hlt">fissure</span> sealant has the potential to inhibit enamel demineralization. How to cite this article: Zawaideh FI, Owais AI, Kawaja W. Ability of pit and <span class="hlt">fissure</span> sealant-containing amorphous calcium phosphate to inhibit enamel demineralization. Int J Clin Pediatr Dent 2016;9(1):10-14. PMID:27274148</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/21232364','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/21232364"><span id="translatedtitle">Biogeography of hydrothermal <span class="hlt">vent</span> communities along seafloor spreading centers.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Van Dover, C L</p> <p>1990-08-01</p> <p>Compared to terrestrial and shallow-water habitats, deep-sea hydrothermal <span class="hlt">vents</span> are unique environments characterized by their local insularity, global distribution, individual ephemerality, collective geological longevity, geochemical homogeneity, and their physical and energetic isolation from the catastrophic events implicated in the extinction and speciation of terrestrial and shallow-water forms. Development of <span class="hlt">vent</span> communities has thus occurred in novel biogeographical contexts that challenge our ability to understand evolutionary processes in the deep sea. Recent field work by French, Canadian, German, Japanese and American scientists has revealed intriguing patterns in the taxonomic composition and distribution of <span class="hlt">vent</span> organisms at geographically disjunct study sites. PMID:21232364</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015EPJWC..9202062P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015EPJWC..9202062P"><span id="translatedtitle">Visualization of the air flow behind the automotive benchmark <span class="hlt">vent</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Pech, Ondrej; Jedelsky, Jan; Caletka, Petr; Jicha, Miroslav</p> <p>2015-05-01</p> <p>Passenger comfort in cars depends on appropriate function of the cabin HVAC system. A great attention is therefore paid to the effective function of automotive <span class="hlt">vents</span> and proper formation of the flow behind the ventilation outlet. The article deals with the visualization of air flow from the automotive benchmark <span class="hlt">vent</span>. The visualization was made for two different shapes of the inlet channel connected to the benchmark <span class="hlt">vent</span>. The smoke visualization with the laser knife was used. The influence of the shape of the inlet channel to the airflow direction, its enlargement and position of air flow axis were investigated.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://medlineplus.gov/ency/article/001130.htm','NIH-MEDLINEPLUS'); return false;" href="https://medlineplus.gov/ency/article/001130.htm"><span id="translatedtitle">Anal <span class="hlt">fissure</span></span></a></p> <p><a target="_blank" href="http://medlineplus.gov/">MedlinePlus</a></p> <p></p> <p></p> <p>... cream, if pain interferes with normal bowel movements Petroleum jelly Zinc oxide, 1% hydrocortisone cream, Preparation H, ... is accredited by URAC, also known as the American Accreditation HealthCare Commission (www.urac.org). URAC's accreditation ...</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li class="active"><span>19</span></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_19 --> <div id="page_20" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li class="active"><span>20</span></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="381"> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.fascrs.org/patients/disease-condition/anal-fissure','NIH-MEDLINEPLUS'); return false;" href="https://www.fascrs.org/patients/disease-condition/anal-fissure"><span id="translatedtitle">Anal <span class="hlt">Fissure</span></span></a></p> <p><a target="_blank" href="http://medlineplus.gov/">MedlinePlus</a></p> <p></p> <p></p> <p>Skip to main content ASCRS Patients Educational Resources Diseases and Conditions Patient Education Library Patient Success Stories Treatments and Screening Resources Find a Surgeon Hereditary Colorectal Cancer Registries Helpful Links Physicians ...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.aaom.com/index.php?option=com_content&view=article&id=130:fissured-tongue&catid=22:patient-condition-information&Itemid=120','NIH-MEDLINEPLUS'); return false;" href="http://www.aaom.com/index.php?option=com_content&view=article&id=130:fissured-tongue&catid=22:patient-condition-information&Itemid=120"><span id="translatedtitle"><span class="hlt">Fissured</span> Tongue</span></a></p> <p><a target="_blank" href="http://medlineplus.gov/">MedlinePlus</a></p> <p></p> <p></p> <p>... Executive Committee Board of Trustees Governance Past Presidents Staff/Contact History Awards Our Partners Membership Membership Categories Renew Your Membership Login Fellowship Academic Fellowship Affiliate Fellowship (AFAOM) Application Process Fellowship Study ...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/25710951','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/25710951"><span id="translatedtitle">Treating pit-and-<span class="hlt">fissure</span> caries: a systematic review and network meta-analysis.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Schwendicke, F; Jäger, A M; Paris, S; Hsu, L Y; Tu, Y K</p> <p>2015-04-01</p> <p>For shallow or moderately deep pit-and-<span class="hlt">fissure</span> lesions, various treatment options are available: (1) noninvasive treatments (e.g., fluoride application, antibacterial treatments, oral hygiene advice) avoid any dental hard tissue removal; (2) microinvasive treatments (e.g., sealing) remove only a few micrometers of hard tissues by etching; and minimally invasive methods (e.g., "preventive" resin/sealant restoration) remove carious dentin but avoid sacrificing sound tissues. We aimed at systematically reviewing and comparing these strategies for treating pit-and-<span class="hlt">fissure</span> lesions in permanent teeth using network meta-analysis. Randomized or nonrandomized clinical trials investigating shallow or moderately deep primary caries lesions in <span class="hlt">fissured</span> or pitted surfaces were included. We compared the risk of requiring invasive treatments or any retreatments in noninvasive, microinvasive, and minimally invasive treated lesions; untreated lesions were used as controls. Five electronic databases were systematically screened up to September 2013 and cross-referencing performed. Pairwise and network meta-analyses were performed and odds ratios and 95% confidence intervals (CI) calculated. Certainty of estimates was evaluated via GRADE criteria. From a total of 2,214 identified records, 14 studies representing 1,440 patients with 3,551 treated lesions were included. Pairwise meta-analysis found microinvasive and minimally invasive treated lesions to require less invasive retreatments than control lesions (odds ratios [95% confidence intervals]: 0.13 [0.07 to 0.26], 0.13 [0.03 to 0.50], respectively), whereas the estimate for noninvasively treated lesions remained nonsignificant (0.64 [0.39 to 1.06]). These findings were reflected in the strategy ranking stemming from network meta-analysis (first, minimally invasive; second, microinvasive; third, noninvasive). However, microinvasive treatment required significantly more total retreatments (including resealing) than minimally or</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/6239257','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/6239257"><span id="translatedtitle">[Endotracheal hemorrhage caused by <span class="hlt">fissuration</span> of the innominate artery during prolonged intubation. Surgical treatment].</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Couraud, L; Hafez, A; Velly, J F</p> <p>1984-11-24</p> <p>We present our surgical procedure for the control of tracheal haemorrhages due to <span class="hlt">fissuration</span> of the innominate artery in patients with prolonged tracheal intubation or tracheostomy. Temporary haemostasis and protection of the airways against flooding are ensured by downward advancement of the tube, overinflation of the cuffs and digital pressure if required. The fistula is then located and surgical haemostasis is obtained by resection of the innominate artery away from the infected area. The arterial stumps are covered up for protection against secondary infection. Re-establishment of blood flow is not systematic. Cervicosternotomy is regarded as the incision of choice. No complication was encountered in patients treated by this method. PMID:6239257</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/22526973','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/22526973"><span id="translatedtitle">A prospective randomized trial comparing stapler and laser techniques for interlobar <span class="hlt">fissure</span> completion during pulmonary lobectomy.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Marulli, Giuseppe; Droghetti, Andrea; Di Chiara, Francesco; Calabrese, Francesca; Rebusso, Alessandro; Perissinotto, Egle; Muriana, Giovanni; Rea, Federico</p> <p>2013-02-01</p> <p>Alveolar air leaks, often resulting from lung tissue traumatization during dissection of <span class="hlt">fissures</span>, still remain a challenging problem in lung surgery. Several tools and techniques have been used to reduce air leakage, but none was judged ideal. This prospective, randomized trial was designed to evaluate the feasibility, safety, and effectiveness of completion of <span class="hlt">fissures</span> during pulmonary lobectomy by using a laser system. A standard stapler technique was used for comparison; the primary goal was to reach at least a comparable result. Forty-four patients were enrolled, 22 were treated with standard technique by using staplers (S) and 22 underwent laser (L) dissection. Randomization to one of the two groups was intraoperative after evaluating the presence of incomplete <span class="hlt">fissure</span> (grade 3-4 following Craig's classification). A Thulium laser 2010 nm (Cyber TM, Quanta System, Italy) was used at power of 40 W. Outcome primary measures were the evaluation and duration of intra- and postoperative air leaks, the rate of complications, and the hospital stay. Air leaks (2.1 ± 4.2 vs 3.6 ± 7.2 days; p = 0.98) and chest tube duration (6.4 ± 4.2 vs 7.5 ± 6.3 days, p = 0.44) were lower in L compared with S group even if these were not statistically significant. Complications (36.4 vs 77.3 %; p = 0.006), hospital stay (6.9 ± 3.8 vs 9.9 ± 6.9 days; p = 0.03), hospitalization costs (5,650 vs 8,147 euros; p = 0.01), and procedure costs (77 % of difference; p < 0.0001) were significantly lower for L group, while operative time was longer (197 ± 34 vs 158 ± 41 min; p = 0.004). The use of laser dissection to prevent postoperative air leaks is effective and comparable with stapler technique. Aero-haemostatic laser properties (by sealing of small blood vessels and checking air leaks) allow a safe application during pulmonary lobectomy in interlobar <span class="hlt">fissure</span> completion avoiding stapler use. PMID:22526973</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016RMRE...49..477M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016RMRE...49..477M"><span id="translatedtitle">A Stress-Induced Permeability Evolution Model for <span class="hlt">Fissured</span> Porous Media</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Ma, Jianjun; Wang, Jun</p> <p>2016-02-01</p> <p>A unified permeability evolution model is proposed to capture the evolution of permeability induced by stress. This model is formulated within a conventional permeability-porosity power function, with special attentions being paid to the effects of shear deformation-induced tortuosity and compaction-induced closure of <span class="hlt">fissures</span> through a permeability resistance parameter. This model contains a small amount number of parameters, which can be calibrated based on conventional experiments. The proposed model is validated through comparison between model simulation and experimental results for sandstones under a wide range of confining pressures. Good performance demonstrates the capability of the proposed permeability evolution model.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015PIAHS.372..291C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015PIAHS.372..291C"><span id="translatedtitle">Continuous monitoring of an earth <span class="hlt">fissure</span> in Chino, California, USA - a management tool</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Carpenter, M. C.</p> <p>2015-11-01</p> <p>Continuous measurements of deformation have been made in Chino, California across an earth <span class="hlt">fissure</span> and nearby unfissured soil since 2011 in two buried, horizontal, 150 mm pipes, 51 m long, which are connected by sealed boxes enclosing vertical posts at mostly 6 m intervals. Horizontal displacements and normal strain are measured in one line using nine end-to-end quartz tubes that are attached to posts and span <span class="hlt">fissured</span> or unfissured soil. The free ends of the tubes are supported by slings and move relative to the attachment post of the next quartz tube. Linear variable differential transformer (LVDT) sensors measure the relative movements. Five biaxial tilt sensors were also attached to selected posts in that line. Relative vertical movement was measured at nine locations along the line in the second pipe using low-level differential pressure sensors. The second pipe is half full of water giving a free water surface along its length. Data are recorded on a Campbell CR10 using multiplexers. The quartz-tube horizontal extensometers have exhibited more than 3 mm of predominantly elastic opening and closing in response to about 32 m of seasonal drawdown and recovery, respectively, in an observation well 0.8 km to the south. The nearest production well is 1.6 km to the west. The horizontal strain was 5.9 × 10-5 or 30 % of the lowest estimate of strain-at-failure for alluvium. Maximum relative vertical movement was 4.8 mm. Maximum tilt in the <span class="hlt">fissure</span> zone was 0.09 arcdeg while tilt at a separate sensor 100 m to the east was 0.86 arcdeg, indicating a wider zone of deformation than is spanned by the instrumentation. High correlation of horizontal displacements during drawdown, and especially recovery, with change in effective stress supports differential compaction as the mechanism for earth-<span class="hlt">fissure</span> movement. The continuous measurements of horizontal strain coupled with water-level fluctuations and vertical borehole extensometry can provide a real-time adaptive management</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014IzAOP..50..745E','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014IzAOP..50..745E"><span id="translatedtitle">Tectonics and magma chambers of the recent Tolbachik <span class="hlt">Fissure</span> Eruption (Kamchatka Peninsula)</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Ermakov, V. A.; Gontovaya, L. I.; Senyukov, S. L.</p> <p>2014-12-01</p> <p>Structural-geological, petrological, seismotectonic, and seismotomographic data received in regions of areal volcanism of the south-southwest sector of the Plosky Tolbachik volcano area are considered. The <span class="hlt">fissure</span> eruption occurring here from November 2012 to the middle of September 2013 was called 50 years of IVS after the 50th anniversary of the Institute of Volcanology and Seismology, Far Eastern Branch, Russian Academy of Sciences. A joint analysis of new and retrospective data allows us to suggest a model for the recent eruption and formulate some problems for future studies and eruption forecasting.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2015PIAHS.372..305Z&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2015PIAHS.372..305Z&link_type=ABSTRACT"><span id="translatedtitle">Different scale land subsidence and ground <span class="hlt">fissure</span> monitoring with multiple InSAR techniques over Fenwei basin, China</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Zhao, C.; Zhang, Q.; Yang, C.; Zhang, J.; Zhu, W.; Qu, F.; Liu, Y.</p> <p>2015-11-01</p> <p>Fenwei basin, China, composed by several sub-basins, has been suffering severe geo-hazards in last 60 years, including large scale land subsidence and small scale ground <span class="hlt">fissure</span>, which caused serious infrastructure damages and property losses. In this paper, we apply different InSAR techniques with different SAR data to monitor these hazards. Firstly, combined small baseline subset (SBAS) InSAR method and persistent scatterers (PS) InSAR method is used to multi-track Envisat ASAR data to retrieve the large scale land subsidence covering entire Fenwei basin, from which different land subsidence magnitudes are analyzed of different sub-basins. Secondly, PS-InSAR method is used to monitor the small scale ground <span class="hlt">fissure</span> deformation in Yuncheng basin, where different spatial deformation gradient can be clearly discovered. Lastly, different track SAR data are contributed to retrieve two-dimensional deformation in both land subsidence and ground <span class="hlt">fissure</span> region, Xi'an, China, which can be benefitial to explain the occurrence of ground <span class="hlt">fissure</span> and the correlation between land subsidence and ground <span class="hlt">fissure</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010AGUFM.B23J..02P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010AGUFM.B23J..02P"><span id="translatedtitle">Energy and Carbon Flow: Comparing ultramafic- and basalt-hosted <span class="hlt">vents</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Perner, M.; Bach, W.; Seifert, R.; Strauss, H.; Laroche, J.</p> <p>2010-12-01</p> <p>In deep-sea <span class="hlt">vent</span> habitats hydrothermal fluids provide the grounds for life by supplying reduced inorganic compounds (e.g. H2, sulfide). Chemolithoautotrophs can oxidize these substrates hereby yielding energy, which can then be used to fuel autotrophic CO2 fixation. Depending on the <span class="hlt">type</span> of host rocks (and the degree of admixed ambient seawater) the availability of inorganic electron donors can vary considerably. While in ultramafic-hosted <span class="hlt">vents</span> H2 levels are high and H2-oxidizing metabolisms are thought to dominate, in basalt-hosted <span class="hlt">vents</span>, H2 is much lower and microbial sulfide oxidation is considered to prevail [1, 2]. We have investigated the effect of H2 and sulfide availability on the microbial community of distinct H2-rich and H2-poor <span class="hlt">vent</span> sites along the Mid-Atlantic Ridge. Hydrothermally influenced samples were collected from the H2-rich ultramafic-hosted Logatchev field (15°N) and the comparatively H2-poor basalt-hosted <span class="hlt">vents</span> from 5°S and 9°S. We conducted catabolic energy calculations to estimate the potential of various electron donors to function as microbial energy sources. We performed incubation experiments with hydrothermal fluids amended with H2 or sulfide and radioactively labelled bicarbonate and determined H2 and sulfide consumption and carbon incorporation rates. We constructed metagenomic libraries for sequence-based screening of genes encoding key enzymes for H2 uptake (NiFe uptake hydrogenases, group 1), sulfide oxidation (sulfide quinone oxidoreductase, sqr) and CO2 fixation pathways (RubisCOs of the Calvin cycle [CBB] and beta-subunit of the ATP citrate lyase of the reductive tricarboxylic acid cycle [rTCA]). We evaluated parts of the metagenomes from basalt-hosted sites by pyrosequencing. Based on our incubation experiments - under the conditions applied - we could not confirm that generally H2 consumption rates and biomass syntheses in fluids derived from ultramafic-hosted locations are significantly enhanced over those from basalt</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.gpo.gov/fdsys/pkg/CFR-2011-title46-vol5/pdf/CFR-2011-title46-vol5-sec153-352.pdf','CFR2011'); return false;" href="https://www.gpo.gov/fdsys/pkg/CFR-2011-title46-vol5/pdf/CFR-2011-title46-vol5-sec153-352.pdf"><span id="translatedtitle">46 CFR 153.352 - B/3 and 4 m <span class="hlt">venting</span> system outlets.</span></a></p> <p><a target="_blank" href="http://www.gpo.gov/fdsys/browse/collectionCfr.action?selectedYearFrom=2011&page.go=Go">Code of Federal Regulations, 2011 CFR</a></p> <p></p> <p>2011-10-01</p> <p>... 46 Shipping 5 2011-10-01 2011-10-01 false B/3 and 4 m <span class="hlt">venting</span> system outlets. 153.352 Section 153.352 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) CERTAIN BULK DANGEROUS CARGOES... Cargo <span class="hlt">Venting</span> Systems § 153.352 B/3 and 4 m <span class="hlt">venting</span> system outlets. A B/3 or 4 m <span class="hlt">venting</span> system...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2016EGUGA..1813553K&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2016EGUGA..1813553K&link_type=ABSTRACT"><span id="translatedtitle">3D structure and formation of hydrothermal <span class="hlt">vent</span> complexes in the Møre Basin</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kjoberg, Sigurd; Schmiedel, Tobias; Planke, Sverre; Svensen, Henrik H.; Galland, Oliver; Jerram, Dougal A.</p> <p>2016-04-01</p> <p>The mid-Norwegian Møre margin is regarded as a <span class="hlt">type</span> example of a volcanic rifted margin, with its formation usually related to the influence of the Icelandic plume activity. The area is characterized by the presence of voluminous basaltic complexes such as extrusive lava sequences, intrusive sills and dikes, and hydrothermal <span class="hlt">vent</span> complexes within the Møre Basin. Emplacement of hydrothermal <span class="hlt">vent</span> complexes is accommodated by deformation of the host rock. The edges of igneous intrusions mobilize fluids by heat transfer into the sedimentary host rock (aureoles). Fluid expansion may lead to formation of piercing structures due to upward fluid migration. Hydrothermal <span class="hlt">vent</span> complexes induce bending of overlying strata, leading to the formation of dome structures at the paleo-surface. These dome structures are important as they indicate the accommodation created for the intrusions by deformation of the upper layers of the stratigraphy, and may form important structures in many volcanic margins. Both the morphological characteristics of the upper part and the underlying feeder-structure (conduit-zone) can be imaged and studied on 3D seismic data. Seismic data from the Tulipan prospect located in the western part of the Møre Basin have been used in this study. The investigation focusses on (1) the <span class="hlt">vent</span> complex geometries, (2) the induced surface deformation patterns, (3) the relation to the intrusions (heat source), as well as (4) the emplacement depth of the hydrothermal <span class="hlt">vent</span> complexes. We approach this by doing a detailed 3D seismic interpretation of the Tulipan seismic data cube. The complexes formed during the initial Eocene, and are believed to be a key factor behind the rapid warming event called the Paleocene-Eocene thermal maximum (PETM). The newly derived understanding of age, eruptive deposits, and formation of hydrothermal <span class="hlt">vent</span> complexes in the Møre Basin enables us to contribute to the general understanding of the igneous plumbing system in volcanic basins and</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('//www.loc.gov/pictures/collection/hh/item/ca1500.photos.012939p/','SCIGOV-HHH'); return false;" href="//www.loc.gov/pictures/collection/hh/item/ca1500.photos.012939p/"><span id="translatedtitle">48. DETAIL VIEW OF AIR <span class="hlt">VENT</span> AT 'CATFISH' LAUNCH PAD ...</span></a></p> <p><a target="_blank" href="http://www.loc.gov/pictures/collection/hh/">Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey</a></p> <p></p> <p></p> <p>48. DETAIL VIEW OF AIR <span class="hlt">VENT</span> AT 'CATFISH' LAUNCH PAD Everett Weinreb, photographer, March 1988 - Mount Gleason Nike Missile Site, Angeles National Forest, South of Soledad Canyon, Sylmar, Los Angeles County, CA</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('//www.loc.gov/pictures/collection/hh/item/ca1500.photos.012938p/','SCIGOV-HHH'); return false;" href="//www.loc.gov/pictures/collection/hh/item/ca1500.photos.012938p/"><span id="translatedtitle">47. VIEW OF AIR <span class="hlt">VENT</span> AT 'CATFISH' SILO, LOOKING SOUTHEAST. ...</span></a></p> <p><a target="_blank" href="http://www.loc.gov/pictures/collection/hh/">Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey</a></p> <p></p> <p></p> <p>47. VIEW OF AIR <span class="hlt">VENT</span> AT 'CATFISH' SILO, LOOKING SOUTHEAST. ENTRANCE TO 'BRAVO' IN BACK Everett Weinreb, photographer, March 1988 - Mount Gleason Nike Missile Site, Angeles National Forest, South of Soledad Canyon, Sylmar, Los Angeles County, CA</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('//www.loc.gov/pictures/collection/hh/item/ca3272.photos.206903p/','SCIGOV-HHH'); return false;" href="//www.loc.gov/pictures/collection/hh/item/ca3272.photos.206903p/"><span id="translatedtitle">View of building 11070 showing <span class="hlt">vents</span> and forced air system ...</span></a></p> <p><a target="_blank" href="http://www.loc.gov/pictures/collection/hh/">Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey</a></p> <p></p> <p></p> <p>View of building 11070 showing <span class="hlt">vents</span> and forced air system on east side, looking southwest. - Naval Ordnance Test Station Inyokern, China Lake Pilot Plant, Maintenance Shop, C Street, China Lake, Kern County, CA</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('//www.loc.gov/pictures/collection/hh/item/ca1499.photos.012875p/','SCIGOV-HHH'); return false;" href="//www.loc.gov/pictures/collection/hh/item/ca1499.photos.012875p/"><span id="translatedtitle">10. VIEW OF SILO DOORS, AIR <span class="hlt">VENTS</span>, AND ESCAPE HATCH, ...</span></a></p> <p><a target="_blank" href="http://www.loc.gov/pictures/collection/hh/">Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey</a></p> <p></p> <p></p> <p>10. VIEW OF SILO DOORS, AIR <span class="hlt">VENTS</span>, AND ESCAPE HATCH, LOOKING EAST. WHITE STRUCTURES BELONG TO CURRENT OCCUPANTS Everett Weinreb, photographer, April 1988 - Los Pinetos Nike Missile Site, Santa Clara Road, Los Angeles National Forest, Sylmar, Los Angeles County, CA</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('//www.loc.gov/pictures/collection/hh/item/mo1878.photos.364072p/','SCIGOV-HHH'); return false;" href="//www.loc.gov/pictures/collection/hh/item/mo1878.photos.364072p/"><span id="translatedtitle">Looking North at Reactor Number One and Air <span class="hlt">Vent</span> on ...</span></a></p> <p><a target="_blank" href="http://www.loc.gov/pictures/collection/hh/">Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey</a></p> <p></p> <p></p> <p>Looking North at Reactor Number One and Air <span class="hlt">Vent</span> on Fourth Floor of Oxide Building - Hematite Fuel Fabrication Facility, Oxide Building & Oxide Loading Dock, 3300 State Road P, Festus, Jefferson County, MO</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=GPN-2000-000700&hterms=Gas+explosion+model&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3DGas%2Bexplosion%2Bmodel','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=GPN-2000-000700&hterms=Gas+explosion+model&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3DGas%2Bexplosion%2Bmodel"><span id="translatedtitle"><span class="hlt">Vent</span> Flowing Cold Gas and T/C Rake</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p></p> <p>1963-01-01</p> <p><span class="hlt">Vent</span> flowing cryogenic fuel and T/C Rake mounted on a 1/10 scale model Centaur in the l0 x l0 Foot Supersonic Wind Tunnel. The fuel being used is liquid hydrogen. The point of the test is to determine how far to expel <span class="hlt">venting</span> fuel from the rocket body to prevent explosion at the base of the vehicle. This <span class="hlt">vent</span> is used as a safety valve for the fumes created when loading the fuel tanks during launch preparation. Liquid hydrogen has to be kept at a very low temperature. As it heats, it turns to gas and increases pressure in the tank. It therefore has to be <span class="hlt">vented</span> overboard while the rocket sits on the pad. The test is being run at the Lewis Research Center, now known as John H. Glenn Research Center, Lewis Field.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.gpo.gov/fdsys/pkg/CFR-2014-title40-vol26/pdf/CFR-2014-title40-vol26-sec265-1032.pdf','CFR2014'); return false;" href="https://www.gpo.gov/fdsys/pkg/CFR-2014-title40-vol26/pdf/CFR-2014-title40-vol26-sec265-1032.pdf"><span id="translatedtitle">40 CFR 265.1032 - Standards: Process <span class="hlt">vents</span>.</span></a></p> <p><a target="_blank" href="http://www.gpo.gov/fdsys/browse/collectionCfr.action?selectedYearFrom=2014&page.go=Go">Code of Federal Regulations, 2014 CFR</a></p> <p></p> <p>2014-07-01</p> <p>... owner or operator of a fa-cil-ity with process <span class="hlt">vents</span> associated with distillation, fractionation, thin-film evaporation, solvent extraction or -air or steam stripping operations man-aging haz-ard-ous...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.gpo.gov/fdsys/pkg/CFR-2012-title40-vol27/pdf/CFR-2012-title40-vol27-sec265-1032.pdf','CFR2012'); return false;" href="https://www.gpo.gov/fdsys/pkg/CFR-2012-title40-vol27/pdf/CFR-2012-title40-vol27-sec265-1032.pdf"><span id="translatedtitle">40 CFR 265.1032 - Standards: Process <span class="hlt">vents</span>.</span></a></p> <p><a target="_blank" href="http://www.gpo.gov/fdsys/browse/collectionCfr.action?selectedYearFrom=2012&page.go=Go">Code of Federal Regulations, 2012 CFR</a></p> <p></p> <p>2012-07-01</p> <p>... owner or operator of a fa-cil-ity with process <span class="hlt">vents</span> associated with distillation, fractionation, thin-film evaporation, solvent extraction or -air or steam stripping operations man-aging haz-ard-ous...</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li class="active"><span>20</span></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_20 --> <div id="page_21" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li class="active"><span>21</span></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="401"> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.gpo.gov/fdsys/pkg/CFR-2013-title40-vol27/pdf/CFR-2013-title40-vol27-sec265-1032.pdf','CFR2013'); return false;" href="https://www.gpo.gov/fdsys/pkg/CFR-2013-title40-vol27/pdf/CFR-2013-title40-vol27-sec265-1032.pdf"><span id="translatedtitle">40 CFR 265.1032 - Standards: Process <span class="hlt">vents</span>.</span></a></p> <p><a target="_blank" href="http://www.gpo.gov/fdsys/browse/collectionCfr.action?selectedYearFrom=2013&page.go=Go">Code of Federal Regulations, 2013 CFR</a></p> <p></p> <p>2013-07-01</p> <p>... owner or operator of a fa-cil-ity with process <span class="hlt">vents</span> associated with distillation, fractionation, thin-film evaporation, solvent extraction or -air or steam stripping operations man-aging haz-ard-ous...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('//www.loc.gov/pictures/collection/hh/item/fl0440.photos.207442p/','SCIGOV-HHH'); return false;" href="//www.loc.gov/pictures/collection/hh/item/fl0440.photos.207442p/"><span id="translatedtitle">DETAILS, ENTRY AND ROOF <span class="hlt">VENT</span>, SOUTHERN SECTION OF THE WEST ...</span></a></p> <p><a target="_blank" href="http://www.loc.gov/pictures/collection/hh/">Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey</a></p> <p></p> <p></p> <p>DETAILS, ENTRY AND ROOF <span class="hlt">VENT</span>, SOUTHERN SECTION OF THE WEST (FRONT) FACADE, LOOKING NORTHEAST - Eglin Air Force Base, Storehouse & Company Administration, Southeast of Flager Road, Nassau Lane, & southern edge of Weekly Bayou, Valparaiso, Okaloosa County, FL</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('//www.loc.gov/pictures/collection/hh/item/fl0440.photos.207437p/','SCIGOV-HHH'); return false;" href="//www.loc.gov/pictures/collection/hh/item/fl0440.photos.207437p/"><span id="translatedtitle">DETAILS, ROOF <span class="hlt">VENTS</span> AND WINDOWS, NORTHERN CORNER SECTION OF THE ...</span></a></p> <p><a target="_blank" href="http://www.loc.gov/pictures/collection/hh/">Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey</a></p> <p></p> <p></p> <p>DETAILS, ROOF <span class="hlt">VENTS</span> AND WINDOWS, NORTHERN CORNER SECTION OF THE EAST (REAR) FACADE, LOOKING NORTHWEST - Eglin Air Force Base, Storehouse & Company Administration, Southeast of Flager Road, Nassau Lane, & southern edge of Weekly Bayou, Valparaiso, Okaloosa County, FL</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.gpo.gov/fdsys/pkg/CFR-2011-title40-vol20/pdf/CFR-2011-title40-vol20-sec87-11.pdf','CFR2011'); return false;" href="https://www.gpo.gov/fdsys/pkg/CFR-2011-title40-vol20/pdf/CFR-2011-title40-vol20-sec87-11.pdf"><span id="translatedtitle">40 CFR 87.11 - Standard for fuel <span class="hlt">venting</span> emissions.</span></a></p> <p><a target="_blank" href="http://www.gpo.gov/fdsys/browse/collectionCfr.action?selectedYearFrom=2011&page.go=Go">Code of Federal Regulations, 2011 CFR</a></p> <p></p> <p>2011-07-01</p> <p>... fuel <span class="hlt">venting</span> emissions shall be discharged into the atmosphere from any new or in-use aircraft gas... discharge to the atmosphere of fuel drained from fuel nozzle manifolds after engines are shut down and...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=20040065937&hterms=deep+vent&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3Ddeep%2Bvent','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=20040065937&hterms=deep+vent&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3Ddeep%2Bvent"><span id="translatedtitle">Optical Detection of Organic Chemical Biosignatures at Hydrothermal <span class="hlt">Vents</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Conrad, P. G.; Lane, A. L.; Bhartia, R.; Hug, W. H.</p> <p>2004-01-01</p> <p>We have developed a non-contact, optical life detection instrument that can detect organic chemical biosignatures in a number of different environments, including dry land, shallow aqueous, deep marine or in ice. Hence, the instrument is appropriate as a biosignature survey tool both for Mars exploration or in situ experiments in an ice-covered ocean such as one might wish to explore on Europa. Here, we report the results we obtained on an expedition aboard the Russian oceanographic vessel Akademik Mstislav Keldysh to hydrothermal <span class="hlt">vent</span> sites in the Pacific Ocean using our life detection instrument MCDUVE, a multichannel, deep ultraviolet excitation fluorescence detector. MCDUVE detected organic material distribution on rocks near the <span class="hlt">vent</span>, as well as direct detection of organisms, both microbial and microscopic. We also were able to detect organic material issuing directly from <span class="hlt">vent</span> chimneys, measure the organic signature of the water column as we ascended, and passively observe the emission of light directly from some <span class="hlt">vents</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('//www.loc.gov/pictures/collection/hh/item/ct0598.photos.317472p/','SCIGOV-HHH'); return false;" href="//www.loc.gov/pictures/collection/hh/item/ct0598.photos.317472p/"><span id="translatedtitle">42. VIEW EAST OF PLASTIC STACK (PROBABLY PVC) WHICH <span class="hlt">VENTED</span> ...</span></a></p> <p><a target="_blank" href="http://www.loc.gov/pictures/collection/hh/">Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey</a></p> <p></p> <p></p> <p>42. VIEW EAST OF PLASTIC STACK (PROBABLY PVC) WHICH <span class="hlt">VENTED</span> FUMES FROM THE DIPPING OPERATIONS IN BUILDING 49A; BUILDING 49 IS AT THE LEFT OF THE PHOTOGRAPH - Scovill Brass Works, 59 Mill Street, Waterbury, New Haven County, CT</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('//www.loc.gov/pictures/collection/hh/item/mn0595.photos.197886p/','SCIGOV-HHH'); return false;" href="//www.loc.gov/pictures/collection/hh/item/mn0595.photos.197886p/"><span id="translatedtitle">61. View of exhaust air <span class="hlt">vent</span> (foreground), escape hatch, and ...</span></a></p> <p><a target="_blank" href="http://www.loc.gov/pictures/collection/hh/">Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey</a></p> <p></p> <p></p> <p>61. View of exhaust air <span class="hlt">vent</span> (foreground), escape hatch, and elevator doors at launch pad "A" with building 157, sentry control box on right, looking southwest - Nike Missile Battery MS-40, County Road No. 260, Farmington, Dakota County, MN</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('//www.loc.gov/pictures/collection/hh/item/id0093.photos.059686p/','SCIGOV-HHH'); return false;" href="//www.loc.gov/pictures/collection/hh/item/id0093.photos.059686p/"><span id="translatedtitle">7. Front of northern kiln group, looking north. <span class="hlt">Vents</span> are ...</span></a></p> <p><a target="_blank" href="http://www.loc.gov/pictures/collection/hh/">Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey</a></p> <p></p> <p></p> <p>7. Front of northern kiln group, looking north. <span class="hlt">Vents</span> are visible in all kilns, in two rows above present grade. - Warren King Charcoal Kilns, 5 miles west of Idaho Highway 28, Targhee National Forest, Leadore, Lemhi County, ID</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('//www.loc.gov/pictures/collection/hh/item/hi0873.photos.576217p/','SCIGOV-HHH'); return false;" href="//www.loc.gov/pictures/collection/hh/item/hi0873.photos.576217p/"><span id="translatedtitle">DETAIL OF WEST END SLIDING DOOR AND EAVE <span class="hlt">VENTS</span> ON ...</span></a></p> <p><a target="_blank" href="http://www.loc.gov/pictures/collection/hh/">Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey</a></p> <p></p> <p></p> <p>DETAIL OF WEST END SLIDING DOOR AND EAVE <span class="hlt">VENTS</span> ON THE SOUTH SIDE - Hickam Field, Practice Bomb Loading Shed, Bomb Storage Road near the intersection of Moffet and Kamakahi Streets, Honolulu, Honolulu County, HI</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('//www.loc.gov/pictures/collection/hh/item/ca2228.photos.324343p/','SCIGOV-HHH'); return false;" href="//www.loc.gov/pictures/collection/hh/item/ca2228.photos.324343p/"><span id="translatedtitle">22. STEEL ARCH SEGMENT AND <span class="hlt">VENT</span> IN OFFICE, ROOM 2351, ...</span></a></p> <p><a target="_blank" href="http://www.loc.gov/pictures/collection/hh/">Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey</a></p> <p></p> <p></p> <p>22. STEEL ARCH SEGMENT AND <span class="hlt">VENT</span> IN OFFICE, ROOM 2351, SECOND FLOOR, NORTH SIDE. - Hughes Aircraft Company, Processing & Electronics Building, 6775 Centinela Avenue, Los Angeles, Los Angeles County, CA</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20080003809','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20080003809"><span id="translatedtitle">Turbofan Engine Core Compartment <span class="hlt">Vent</span> Aerodynamic Configuration Development Methodology</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Hebert, Leonard J.</p> <p>2006-01-01</p> <p>This paper presents an overview of the design methodology used in the development of the aerodynamic configuration of the nacelle core compartment <span class="hlt">vent</span> for a typical Boeing commercial airplane together with design challenges for future design efforts. Core compartment <span class="hlt">vents</span> exhaust engine subsystem flows from the space contained between the engine case and the nacelle of an airplane propulsion system. These subsystem flows typically consist of precooler, oil cooler, turbine case cooling, compartment cooling and nacelle leakage air. The design of core compartment <span class="hlt">vents</span> is challenging due to stringent design requirements, mass flow sensitivity of the system to small changes in <span class="hlt">vent</span> exit pressure ratio, and the need to maximize overall exhaust system performance at cruise conditions.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19970025336','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19970025336"><span id="translatedtitle"><span class="hlt">Vented</span> Tank Resupply Experiment--Flight Test Results</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Chato, David J.; Martin, Timothy A.</p> <p>1997-01-01</p> <p>This paper reports the results of the <span class="hlt">Vented</span> Tank Resupply Experiment (VTRE) which was flown as a payload on STS 77. VTRE looks at the ability of vane Propellant Management Devices (PMD) to separate liquid and gas in low gravity. VTRE used two clear 0.8 cubic foot tanks one spherical and one with a short barrel section and transferred Refrigerant 113 between them as well as <span class="hlt">venting</span> it to space. Tests included retention of liquid during transfer, liquid free <span class="hlt">venting</span>, and recovery of liquid into the PMD after thruster firing. Liquid was retained successfully at the highest flow rate tested (2.73 gpm). Liquid free <span class="hlt">vents</span> were achieved for both tanks, although at a higher flow rate (0.1591 cfm) for the spherical tank than the other (0.0400 cfm). Recovery from a thruster firing which moved the liquid to the opposite end of the tank from the PMD was achieved in 30 seconds.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.gpo.gov/fdsys/pkg/CFR-2013-title40-vol21/pdf/CFR-2013-title40-vol21-sec87-11.pdf','CFR2013'); return false;" href="https://www.gpo.gov/fdsys/pkg/CFR-2013-title40-vol21/pdf/CFR-2013-title40-vol21-sec87-11.pdf"><span id="translatedtitle">40 CFR 87.11 - Standard for fuel <span class="hlt">venting</span> emissions.</span></a></p> <p><a target="_blank" href="http://www.gpo.gov/fdsys/browse/collectionCfr.action?selectedYearFrom=2013&page.go=Go">Code of Federal Regulations, 2013 CFR</a></p> <p></p> <p>2013-07-01</p> <p>... fuel <span class="hlt">venting</span> emissions shall be discharged into the atmosphere from any new or in-use aircraft gas... discharge to the atmosphere of fuel drained from fuel nozzle manifolds after engines are shut down and...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.gpo.gov/fdsys/pkg/CFR-2014-title40-vol20/pdf/CFR-2014-title40-vol20-sec87-11.pdf','CFR2014'); return false;" href="https://www.gpo.gov/fdsys/pkg/CFR-2014-title40-vol20/pdf/CFR-2014-title40-vol20-sec87-11.pdf"><span id="translatedtitle">40 CFR 87.11 - Standard for fuel <span class="hlt">venting</span> emissions.</span></a></p> <p><a target="_blank" href="http://www.gpo.gov/fdsys/browse/collectionCfr.action?selectedYearFrom=2014&page.go=Go">Code of Federal Regulations, 2014 CFR</a></p> <p></p> <p>2014-07-01</p> <p>... <span class="hlt">venting</span> emissions shall be discharged into the atmosphere from any new or in-use aircraft gas turbine... the atmosphere of fuel drained from fuel nozzle manifolds after engines are shut down and does...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.gpo.gov/fdsys/pkg/CFR-2014-title14-vol1/pdf/CFR-2014-title14-vol1-sec34-11.pdf','CFR2014'); return false;" href="https://www.gpo.gov/fdsys/pkg/CFR-2014-title14-vol1/pdf/CFR-2014-title14-vol1-sec34-11.pdf"><span id="translatedtitle">14 CFR 34.11 - Standard for fuel <span class="hlt">venting</span> emissions.</span></a></p> <p><a target="_blank" href="http://www.gpo.gov/fdsys/browse/collectionCfr.action?selectedYearFrom=2014&page.go=Go">Code of Federal Regulations, 2014 CFR</a></p> <p></p> <p>2014-01-01</p> <p>... fuel <span class="hlt">venting</span> emissions shall be discharged into the atmosphere from any new or in-use aircraft gas... discharge to the atmosphere of fuel drained from fuel nozzle manifolds after engines are shut down and...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.gpo.gov/fdsys/pkg/CFR-2010-title40-vol20/pdf/CFR-2010-title40-vol20-sec87-11.pdf','CFR'); return false;" href="https://www.gpo.gov/fdsys/pkg/CFR-2010-title40-vol20/pdf/CFR-2010-title40-vol20-sec87-11.pdf"><span id="translatedtitle">40 CFR 87.11 - Standard for fuel <span class="hlt">venting</span> emissions.</span></a></p> <p><a target="_blank" href="http://www.gpo.gov/fdsys/browse/collectionCfr.action?selectedYearFrom=2010&page.go=Go">Code of Federal Regulations, 2010 CFR</a></p> <p></p> <p>2010-07-01</p> <p>... fuel <span class="hlt">venting</span> emissions shall be discharged into the atmosphere from any new or in-use aircraft gas... discharge to the atmosphere of fuel drained from fuel nozzle manifolds after engines are shut down and...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('//www.loc.gov/pictures/collection/hh/item/il0718.photos.034827p/','SCIGOV-HHH'); return false;" href="//www.loc.gov/pictures/collection/hh/item/il0718.photos.034827p/"><span id="translatedtitle">15. SANDSORTING BUILDING, SECOND FLOOR, VIEW OF DUST COLLECTION <span class="hlt">VENTS</span>, ...</span></a></p> <p><a target="_blank" href="http://www.loc.gov/pictures/collection/hh/">Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey</a></p> <p></p> <p></p> <p>15. SAND-SORTING BUILDING, SECOND FLOOR, VIEW OF DUST COLLECTION <span class="hlt">VENTS</span>, LOOKING SOUTHWEST - Mill "C" Complex, Sand-Sorting Building, South of Dee Bennet Road, near Illinois River, Ottawa, La Salle County, IL</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('//www.loc.gov/pictures/collection/hh/item/ca2475.photos.325614p/','SCIGOV-HHH'); return false;" href="//www.loc.gov/pictures/collection/hh/item/ca2475.photos.325614p/"><span id="translatedtitle">DETAIL OF WINDOW AND ROOF <span class="hlt">VENT</span> AT EAST ELEVATION GABLE ...</span></a></p> <p><a target="_blank" href="http://www.loc.gov/pictures/collection/hh/">Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey</a></p> <p></p> <p></p> <p>DETAIL OF WINDOW AND ROOF <span class="hlt">VENT</span> AT EAST ELEVATION GABLE END; CAMERA FACING WEST. - Mare Island Naval Shipyard, Transportation Building & Gas Station, Third Street, south side between Walnut Avenue & Cedar Avenue, Vallejo, Solano County, CA</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('//www.loc.gov/pictures/collection/hh/item/ca2475.photos.325615p/','SCIGOV-HHH'); return false;" href="//www.loc.gov/pictures/collection/hh/item/ca2475.photos.325615p/"><span id="translatedtitle">DETAIL OF SECOND STORY WINDOWS AND ROOF <span class="hlt">VENT</span> ON SOUTH ...</span></a></p> <p><a target="_blank" href="http://www.loc.gov/pictures/collection/hh/">Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey</a></p> <p></p> <p></p> <p>DETAIL OF SECOND STORY WINDOWS AND ROOF <span class="hlt">VENT</span> ON SOUTH END OF EAST ELEVATION; CAMERA WEST. - Mare Island Naval Shipyard, Transportation Building & Gas Station, Third Street, south side between Walnut Avenue & Cedar Avenue, Vallejo, Solano County, CA</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014AGUFM.P41B3898P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014AGUFM.P41B3898P"><span id="translatedtitle">The Implications of Flank <span class="hlt">Vents</span> on Olympus Mons</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Peters, S.; Christensen, P. R.</p> <p>2014-12-01</p> <p>Flank <span class="hlt">vents</span> are a common feature on polygenetic volcanoes. They indicate that magma has propagated away from the main conduit and/or magma chamber. Flank <span class="hlt">vents</span> and flank eruptions have been documented and studied on a number of terrestrial volcanoes and to a lesser degree on Mars. The distribution of volcanic <span class="hlt">vents</span> about a central caldera can provide information on radial dikes and tectonic stresses acting on the volcano, and can constrain models involving the emplacement and flexure of the edifice (e.g. Nakamura, 1976; McGovern and Solomon, 1993). In the absence of spectral data (due to optically thick dust cover) and in situ observations, morphology is a powerful tool for ascertaining the eruptive and tectonic history of Olympus Mons. Approximately 190 high-resolution CTX (Context Camera) images covering Olympus Mons have been mosaicked together. The analysis of a CTX mosaic reveals Mars's largest shield volcano in stunning detail and allows for a thorough analysis of the targeted features. Preliminary results show numerous flank <span class="hlt">vents</span> some of which produce leveed channels on the slopes of Olympus Mons. Some <span class="hlt">vents</span> display varying morphologies, suggesting that the style of volcanism has evolved over time. Flank <span class="hlt">vents</span> are observed to occur over a range of elevations, although a paucity of <span class="hlt">vents</span> is observed on the lower flank. Analyses are ongoing and include mapping the spatial and elevation distribution of flank <span class="hlt">vents</span> on the shield. Once mapped, the distribution of flank <span class="hlt">vents</span> will define the orientation of tectonic stresses acting on Olympus Mons and help determine whether they are influenced by underlying topography, regional scale processes or a combination of both. In addition, these <span class="hlt">vents</span> act as a window into the subsurface which can help characterize dike emplacement within the shield. Furthermore, the morphology of flank <span class="hlt">vents</span> will provide information on the evolution of their eruptive styles. All of this information is crucial to help understand the</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li class="active"><span>21</span></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_21 --> <div id="page_22" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li class="active"><span>22</span></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li><a href="#" onclick='return showDiv("page_24");'>24</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="421"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016GeoRL..43.6212C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016GeoRL..43.6212C"><span id="translatedtitle">Understanding the link between circumferential dikes and eruptive <span class="hlt">fissures</span> around calderas based on numerical and analog models</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Corbi, Fabio; Rivalta, Eleonora; Pinel, Virginie; Maccaferri, Francesco; Acocella, Valerio</p> <p>2016-06-01</p> <p>Active calderas are seldom associated with circumferential eruptive <span class="hlt">fissures</span>, but eroded magmatic complexes reveal widespread circumferential dikes. This suggests that, while the conditions to emplace circumferential dikes are easily met, mechanisms must prevent them from reaching the surface. We explain this discrepancy with experiments of air injection into gelatin shaped as a volcano with caldera. Analog dikes show variable deflection, depending on the competition between overpressure, Pe, and topographic unloading, Pl; when Pl/Pe = 4.8-5.3, the dikes propagate orthogonal to the least compressive stress. Due to the unloading, they become circumferential and stall below the caldera rim; buoyancy is fundamental for the further rise and circumferential <span class="hlt">fissure</span> development. Numerical models quantitatively constrain the stress orientation within the gelatin, explaining the observed circumferential dikes. Our results explain how dikes propagate below the rim of felsic and mafic calderas, but only in the latter they are prone to feed circumferential <span class="hlt">fissures</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/27037717','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/27037717"><span id="translatedtitle">Detailed modeling of palpebral <span class="hlt">fissure</span> and its influence on SAR and temperature rise in human eye under GHz exposures.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Diao, Yinliang; Leung, Sai-Wing; He, Yaqing; Sun, Weinong; Chan, Kwok-Hung; Siu, Yun-Ming; Kong, Richard</p> <p>2016-05-01</p> <p>This article investigates variations in specific absorption rate and temperature rise in human eye caused by changes in palpebral <span class="hlt">fissure</span>, the extent of opening between eyelids, under GHz plane-wave electromagnetic (EM) exposures. Detailed human head models with different palpebral <span class="hlt">fissure</span> features were developed with a refined spatial resolution of 0.25 mm. These head models were then incorporated into both EM and bio-heat simulations, but using finite-difference time-domain method and finite-difference method, respectively. Maximum temperature rise in lens was found to be 0.8°C under EM exposure at 100 W/m(2) . Results reveal that changes in palpebral <span class="hlt">fissure</span> would produce a 0.23°C variation in maximum temperature rise in lens. Bioelectromagnetics. 37:256-263, 2016. © 2016 Wiley Periodicals, Inc. PMID:27037717</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/21956178','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/21956178"><span id="translatedtitle">Novel <span class="hlt">venting</span> technique for intramedullary rod fixation of pathologic fractures.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Wilkens, Kenneth J; Nicolaou, Daemeon A M; Lee, Mark A</p> <p>2011-10-01</p> <p>This article introduces a novel technique to <span class="hlt">vent</span> the femur and potentially decrease the embolic load created by reaming during intramedullary rod fixation of impending pathologic femur fractures. We used readily available operating room equipment to create a distal femoral <span class="hlt">vent</span> hole without interfering with standard intramedullary instrumentation and with minimal increase in surgical time. This technique can be used for the prophylactic intramedullary stabilization of impending pathologic femur fractures from metabolic bone disease, metastatic cancer, and bisphosphonate use. PMID:21956178</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=2247939','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=2247939"><span id="translatedtitle"><span class="hlt">Vent</span>Sim: a simulation model of cardiopulmonary physiology.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Rutledge, G. W.</p> <p>1994-01-01</p> <p><span class="hlt">Vent</span>Sim is a quantitative model that predicts the effects of alternative ventilator settings on the cardiopulmonary physiology of critically ill patients. <span class="hlt">Vent</span>Sim is an expanded version of the physiologic model in <span class="hlt">Vent</span>Plan, an application that provides ventilator-setting recommendations for patients in the intensive care unit. <span class="hlt">Vent</span>Sim includes a ventilator component, an airway component, and a circulation component. The ventilator component predicts the pressures and airflows that are generated by a volume-cycled, constant-flow ventilator. The airway component has anatomic and physiologic deadspace compartments, and two alveolar compartments that participate in gas exchange with two pulmonary blood-flow compartments in the circulatory component. The circulatory component also has a shunt compartment that allows a fraction of blood flow to bypass gas exchange in the lungs, and a tissue compartment that consumes oxygen and generates carbon dioxide. The <span class="hlt">Vent</span>Sim model is a set of linked first-order difference equations, with control variables that correspond to the ventilator settings, dependent variables that correspond to the physiologic state, and one independent variable, time. Because the model has no steady state solution, <span class="hlt">Vent</span>Sim solves the equations by numeric integration, which is computation intensive. Simulation results demonstrate that <span class="hlt">Vent</span>Sim predicts the effects of a variety of physiologic abnormalities that cannot be represented in less complex models such as the <span class="hlt">Vent</span>Plan model. For a ventilator-management application, the time-critical nature of ventilator-setting decisions limits the use of complex models. Advanced ventilator-management applications may include a mechanism to select patient-specific models that balance the trade-off of benefit of model detail and cost of computation delay. PMID:7950050</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1998JGR...103.2597S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1998JGR...103.2597S"><span id="translatedtitle">Fluid <span class="hlt">venting</span> in the eastern Aleutian Subduction Zone</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Suess, Erwin; Bohrmann, Gerhard; von Huene, Roland; Linke, Peter; Wallmann, Klaus; Lammers, Stephan; Sahling, Heiko; Winckler, Gisela; Lutz, Richard A.; Orange, Daniel</p> <p>1998-02-01</p> <p>Fluid <span class="hlt">venting</span> has been observed along 800 km of the Alaska convergent margin. The fluid <span class="hlt">venting</span> sites are located near the deformation front, are controlled by subsurface structures, and exhibit the characteristics of cold seeps seen in other convergent margins. The more important characteristics include (1) methane plumes in the lower water column with maxima above the seafloor which are traceable to the initial deformation ridges; (2) prolific colonies of <span class="hlt">vent</span> biota aligned and distributed in patches controlled by fault scarps, over-steepened folds or outcrops of bedding planes; (3) calcium carbonate and barite precipitates at the surface and subsurface of <span class="hlt">vents</span>; and (4) carbon isotope evidence from tissue and skeletal hard parts of biota, as well as from carbonate precipitates, that <span class="hlt">vents</span> expel either methane- or sulfide-dominated fluids. A biogeochemical approach toward estimating fluid flow rates from individual <span class="hlt">vents</span> based on oxygen flux measurements and <span class="hlt">vent</span> fluid analysis indicates a mean value of 5.5±0.7 L m-2 d-1 for tectonics-induced water flow [Wallmann et al., 1997b]. A geophysical estimate of dewatering from the same area [von Huene et al., 1997] based on sediment porosity reduction shows a fluid loss of 0.02 L m-2 d-1 for a 5.5 km wide converged segment near the deformation front. Our video-guided surveys have documented <span class="hlt">vent</span> biota across a minimum of 0.1% of the area of the convergent segment off Kodiak Island; hence an average rate of 0.006 L m-2 d-1 is estimated from the biogeochemical approach. The two estimates for tectonics-induced water flow from the accretionary prism are in surprisingly good agreement.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015EGUGA..1714688G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015EGUGA..1714688G"><span id="translatedtitle">Morphology and dynamics of explosive <span class="hlt">vents</span> through cohesive rock formations</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Galland, Olivier; Gisler, Galen R.; Haug, Øystein T.</p> <p>2015-04-01</p> <p>Shallow explosive volcanic processes, such as kimberlite volcanism, phreatomagmatic and phreatic activity, produce volcanic <span class="hlt">vents</span> exhibiting a wide variety of morphologies, including vertical pipes and V-shaped <span class="hlt">vents</span>. In this study we report on experimental and numerical models designed to capture a range of <span class="hlt">vent</span> morphologies in an eruptive system (Galland et al., 2014). Using dimensional analysis, we identified key governing dimensionless parameters, in particular the gravitational stress-to-fluid pressure ratio (Π2=P/rho.g.h), and the fluid pressure-to-host rock strength ratio (Π3=P/C). We used combined experimental and numerical models to test the effects of these parameters. The experiments were used to test the effect of Π2 on <span class="hlt">vent</span> morphology and dynamics. A phase diagram demonstrates a separation between two distinct morphologies, with vertical structures occurring at high values of Π2, and diagonal ones at low values of Π2. The numerical simulations were used to test the effect of Π3 on <span class="hlt">vent</span> morphology and dynamics. In the numerical models we see three distinct morphologies: vertical pipes are produced at high values of Π3, diagonal pipes at low values of Π3, while horizontal sills are produced for intermediate values of Π3. Our results show that vertical pipes form by plasticity-dominated yielding for high-energy systems (high Π2 and Π3), whereas diagonal and horizontal <span class="hlt">vents</span> dominantly form by fracturing for lower-energy systems (low Π2 and Π3). Although our models are 2-dimensionnal, they suggest that circular pipes result from plastic yielding of the host rock in a high-energy regime, whereas V-shaped volcanic <span class="hlt">vents</span> result from fracturing of the host rock in lower-energy systems. Galland, O., Gisler, G.R., Haug, Ø.T., 2014. Morphology and dynamics of explosive <span class="hlt">vents</span> through cohesive rock formations. J. Geophys. Res. 119, 10.1002/2014JB011050.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19950057135&hterms=Hydrothermal+vents&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3D%2528Hydrothermal%2Bvents%2529','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19950057135&hterms=Hydrothermal+vents&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3D%2528Hydrothermal%2Bvents%2529"><span id="translatedtitle">The stability of amino acids at submarine hydrothermal <span class="hlt">vent</span> temperatures</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Bada, Jeffrey L.; Miller, Stanley L.; Zhao, Meixun</p> <p>1995-01-01</p> <p>It has been postulated that amino acid stability at hydrothermal <span class="hlt">vent</span> temperatures is controlled by a metastable thermodynamic equilibrium rather than by kinetics. Experiments reported here demonstrate that the amino acids are irreversibly destroyed by heating at 240 C and that quasi-equilibrium calculations give misleading descriptions of the experimental observations. Equilibrium thermodynamic calculations are not applicable to organic compounds under high-temperature submarine <span class="hlt">vent</span> conditions.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3250503','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3250503"><span id="translatedtitle">Antarctic Marine Biodiversity and Deep-Sea Hydrothermal <span class="hlt">Vents</span></span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Chown, Steven L.</p> <p>2012-01-01</p> <p>The diversity of many marine benthic groups is unlike that of most other taxa. Rather than declining from the tropics to the poles, much of the benthos shows high diversity in the Southern Ocean. Moreover, many species are unique to the Antarctic region. Recent work has shown that this is also true of the communities of Antarctic deep-sea hydrothermal <span class="hlt">vents</span>. <span class="hlt">Vent</span> ecosystems have been documented from many sites across the globe, associated with the thermally and chemically variable habitats found around these, typically high temperature, streams that are rich in reduced compounds and polymetallic sulphides. The animal communities of the East Scotia Ridge <span class="hlt">vent</span> ecosystems are very different to those elsewhere, though the microbiota, which form the basis of <span class="hlt">vent</span> food webs, show less differentiation. Much of the biological significance of deep-sea hydrothermal <span class="hlt">vents</span> lies in their biodiversity, the diverse biochemistry of their bacteria, the remarkable symbioses among many of the marine animals and these bacteria, and the prospects that investigations of these systems hold for understanding the conditions that may have led to the first appearance of life. The discovery of diverse and unusual Antarctic hydrothermal <span class="hlt">vent</span> ecosystems provides opportunities for new understanding in these fields. Moreover, the Antarctic <span class="hlt">vents</span> south of 60°S benefit from automatic conservation under the Convention on the Conservation of Antarctic Marine Living Resources and the Antarctic Treaty. Other deep-sea hydrothermal <span class="hlt">vents</span> located in international waters are not protected and may be threatened by growing interests in deep-sea mining. PMID:22235192</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016EGUGA..18.3153C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016EGUGA..18.3153C"><span id="translatedtitle">The link between circumferential dikes and eruptive <span class="hlt">fissures</span> around calderas: insights from numerical and analog models</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Corbi, Fabio; Rivalta, Eleonora; Pinel, Virginie; Maccaferri, Francesco; Acocella, Valerio</p> <p>2016-04-01</p> <p>Active calderas are seldom associated with circumferential eruptive <span class="hlt">fissures</span> along their rim, but eroded portions of extinct magmatic complexes reveal widespread evidence of circumferential dikes. This discrepancy suggests that, while the conditions to emplace circumferential dikes below volcanoes are easily met, mechanisms must exist to arrest the dikes before they reach the surface. Here we explain this discrepancy with laboratory experiments of air injection into a gelatin medium shaped to mimic a volcanic edifice with caldera. Our models show that the ascending dikes experience a variable degree of deflection, depending on the competition between dike overpressure, Pe, and the forcing induced by the topographic load, Pl. When Pl/Pe = 4.3 - 4.5 the analog dikes proceed almost insensitive to the stress rotation and erupt within the caldera. When Pl/Pe = 4.8 - 5.3 the analog dikes closely propagate orthogonal to the least compressive stress σ3 and stall below the caldera rim in a circumferential arrangement. Progressive buoyancy increase through repeated supply of fluid is fundamental for the occurrence of circumferential <span class="hlt">fissures</span>. Complementary numerical models explain the observed circumferential arrangement and validate the experiments. These results contribute defining the shallow magma transfer and related hazard assessment within calderas.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/25134364','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/25134364"><span id="translatedtitle">One-year clinical evaluation of a Glass Carbomer <span class="hlt">fissure</span> sealant, a preliminary study.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Gorseta, K; Glavina, D; Borzabadi-Farahani, A; Van Duinen, R N; Skrinjaric, I; Hill, R G; Lynch, E</p> <p>2014-06-01</p> <p>Glass Carbomer is a new generation of restorative material developed from glass-ionomer cements with possibility of gradual mineralization into fluorapatite. The aim of this clinical trial was to investigate the retention of Glass Carbomer <span class="hlt">fissure</span> sealant after 12 months, in comparison to a commonly used conventional resin-based sealant. Forty-eight teeth in 24 patients [mean (SD) = 8 (2.3) years] with well-delineated <span class="hlt">fissure</span> morphology were randomly divided into two equal groups and sealed with Bis-GMA resin-based Helioseal F (group A, Ivoclar Vivadent, Liechtenstein) and Glass Carbomer (group B, Glass Carbomer Sealant, Glass Carbomer Products, Leiden, Netherlands) using the split mouth design. Materials were placed and set according to the manufacturer's instructions using a polymerization unit Bluephase 16i (Vivadent, Liechtenstein). Complete sealant retentions in both groups were 100% and 75% after 6 and 12 months of clinical service, respectively. There were there were no secondary caries lesions in both groups after 6 months; two new carious lesions were detected in both groups after 12 months. The Mann-Whitney U test revealed no significant difference between the two groups at both evaluations points (P > 0.05). Glass Carbomer material showed a similar retention rate when compared with a resin-based sealant. Future studies are required to examine the long-term performance of Glass Carbomer sealants. PMID:25134364</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1994AnPh...19..459S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1994AnPh...19..459S"><span id="translatedtitle">Des <span class="hlt">Vents</span> et des Jets Astrophysiques</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Sauty, C.</p> <p></p> <p> well expected result from the theory. Although, collimation may be conical, paraboloidal or cylindrical (Part 4), cylindrical collimation is the more likely to occur. The shape of outflows may then be used as a tool to predict physical conditions on the flows or on their source. L'éjection continue de plasma autour d'objets massifs est un phénomène largement répandu en astrophysique, que ce soit sous la forme du <span class="hlt">vent</span> solaire, de <span class="hlt">vents</span> stellaires, de jets d'étoiles en formation, de jets stellaires autour d'objets compacts ou de jets extra-galactiques. Cette zoologie diversifiée fait pourtant l'objet d'un commun effort de modélisation. Le but de cette revue est d'abord de présenter qualitativement le développement, depuis leur origine, des diverses théories de <span class="hlt">vents</span> (Partie 1) et l'inter disciplinarité dans ce domaine. Il s'agit d'une énumération, plus ou moins exhaustive, des idées proposées pour expliquer l'accélération et la morphologie des <span class="hlt">vents</span> et des jets, accompagnée d'une présentation sommaire des aspects observationnels. Cette partie s'abstient de tout aspect faisant appel au formalisme mathématique. Ces écoulements peuvent être décrits, au moins partiellement, en résolvant les équations magnétohydrodynamiques, axisymétriques et stationnaires. Ce formalisme, à la base de la plupart des théories, est exposé dans la Partie 2. Il permet d'introduire quantitativement les intégrales premières qu'un tel système possède. Ces dernières sont amenées à jouer un rôle important dans la compréhension des phénomènes d'accélération ou de collimation, en particulier le taux de perte de masse, le taux de perte de moment angulaire ou l'énergie du rotateur magnétique. La difficulté de modélisation réside dans l'existence de points critiques, propres aux équations non linéaires, qu'il faut franchir. La nature physique et la localisation de ces points critiques fait l'objet d'un débat important car ils sont la clef de voute de la r</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2002seip.conf....7S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2002seip.conf....7S"><span id="translatedtitle">Hydrothermal <span class="hlt">Vents</span> of Juan de Fuca Ridge</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Stark, Joyce</p> <p></p> <p>As a member of REVEL (Research and Education: Volcanoes, Exploration and Life), I had an opportunity to participant in a scientific research cruise focused on the active volcanoes along the Juan de Fuca Ridge, the submarine spreading center off the Washington- Oregon-Canada coast. REVEL was sponsored by the National Science Foundation, University of Washington, Pennsylvania State University and the American Museum of Natural History. We studied the geological, chemical and biological processes associated with active hydrothermal systems and my research focused on the biological communities of the sulfide structures. We worked on board the Woods Hole Oceanographic Institution Vessel, R/V Atlantis and the submersible ALVIN was used to sample the "Black Smokers". As a member of the scientific party, I participated in collection and sorting of biological specimens from the <span class="hlt">vent</span> communities, attended lectures by scientists, contributed to the cruise log website, maintained a journal and developed my own research project. It was my responsibility to bring this cutting-edge research back to the classroom.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3779335','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3779335"><span id="translatedtitle">Cryptic species of Archinome (Annelida: Amphinomida) from <span class="hlt">vents</span> and seeps</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Borda, Elizabeth; Kudenov, Jerry D.; Chevaldonné, Pierre; Blake, James A.; Desbruyères, Daniel; Fabri, Marie-Claire; Hourdez, Stéphane; Pleijel, Fredrik; Shank, Timothy M.; Wilson, Nerida G.; Schulze, Anja; Rouse, Greg W.</p> <p>2013-01-01</p> <p>Since its description from the Galapagos Rift in the mid-1980s, Archinome rosacea has been recorded at hydrothermal <span class="hlt">vents</span> in the Pacific, Atlantic and Indian Oceans. Only recently was a second species described from the Pacific Antarctic Ridge. We inferred the identities and evolutionary relationships of Archinome representatives sampled from across the hydrothermal <span class="hlt">vent</span> range of the genus, which is now extended to cold methane seeps. Species delimitation using mitochondrial cytochrome c oxidase subunit I (COI) recovered up to six lineages, whereas concatenated datasets (COI, 16S, 28S and ITS1) supported only four or five of these as clades. Morphological approaches alone were inconclusive to verify the identities of species owing to the lack of discrete diagnostic characters. We recognize five Archinome species, with three that are new to science. The new species, designated based on molecular evidence alone, include: Archinome levinae n. sp., which occurs at both <span class="hlt">vents</span> and seeps in the east Pacific, Archinome tethyana n. sp., which inhabits Atlantic <span class="hlt">vents</span> and Archinome jasoni n. sp., also present in the Atlantic, and whose distribution extends to the Indian and southwest Pacific Oceans. Biogeographic connections between <span class="hlt">vents</span> and seeps are highlighted, as are potential evolutionary links among populations from <span class="hlt">vent</span> fields located in the east Pacific and Atlantic Oceans, and Atlantic and Indian Oceans; the latter presented for the first time. PMID:24026823</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://pubs.er.usgs.gov/publication/70037208','USGSPUBS'); return false;" href="http://pubs.er.usgs.gov/publication/70037208"><span id="translatedtitle">Monitoring of land subsidence and ground <span class="hlt">fissures</span> in Xian, China 2005-2006: Mapped by sar Interferometry</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Zhao, C.Y.; Zhang, Q.; Ding, X.-L.; Lu, Zhiming; Yang, C.S.; Qi, X.M.</p> <p>2009-01-01</p> <p>The City of Xian, China, has been experiencing significant land subsidence and ground <span class="hlt">fissure</span> activities since 1960s, which have brought various severe geohazards including damages to buildings, bridges and other facilities. Monitoring of land subsidence and ground <span class="hlt">fissure</span> activities can provide useful information for assessing the extent of, and mitigating such geohazards. In order to achieve robust Synthetic Aperture Radar Interferometry (InSAR) results, six interferometric pairs of Envisat ASAR data covering 2005-2006 are collected to analyze the InSAR processing errors firstly, such as temporal and spatial decorrelation error, external DEM error, atmospheric error and unwrapping error. Then the annual subsidence rate during 2005-2006 is calculated by weighted averaging two pairs of D-InSAR results with similar time spanning. Lastly, GPS measurements are applied to calibrate the InSAR results and centimeter precision is achieved. As for the ground <span class="hlt">fissure</span> monitoring, five InSAR cross-sections are designed to demonstrate the relative subsidence difference across ground <span class="hlt">fissures</span>. In conclusion, the final InSAR subsidence map during 2005-2006 shows four large subsidence zones in Xian hi-tech zones in western, eastern and southern suburbs of Xian City, among which two subsidence cones are newly detected and two ground <span class="hlt">fissures</span> are deduced to be extended westward in Yuhuazhai subsidence cone. This study shows that the land subsidence and ground <span class="hlt">fissures</span> are highly correlated spatially and temporally and both are correlated with hi-tech zone construction in Xian during the year of 2005-2006. ?? Springer-Verlag 2008.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/25727314','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/25727314"><span id="translatedtitle">Seagrass biofilm communities at a naturally CO2 -rich <span class="hlt">vent</span>.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Hassenrück, Christiane; Hofmann, Laurie C; Bischof, Kai; Ramette, Alban</p> <p>2015-06-01</p> <p>Seagrass meadows are a crucial component of tropical marine reef ecosystems. Seagrass plants are colonized by a multitude of epiphytic organisms that contribute to broadening the ecological role of seagrasses. To better understand how environmental changes like ocean acidification might affect epiphytic assemblages, the microbial community composition of the epiphytic biofilm of Enhalus acroides was investigated at a natural CO2 <span class="hlt">vent</span> in Papua New Guinea using molecular fingerprinting and next-generation sequencing of 16S and 18S rRNA genes. Both bacterial and eukaryotic epiphytes formed distinct communities at the CO2 -impacted site compared with the control site. This site-related CO2 effect was also visible in the succession pattern of microbial epiphytes. We further found an increased relative sequence abundance of bacterial <span class="hlt">types</span> associated with coral diseases at the CO2 -impacted site (Fusobacteria, Thalassomonas), whereas eukaryotes such as certain crustose coralline algae commonly related to healthy reefs were less diverse. These trends in the epiphytic community of E. acroides suggest a potential role of seagrasses as vectors of coral pathogens and may support previous predictions of a decrease in reef health and prevalence of diseases under future ocean acidification scenarios. PMID:25727314</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/567228','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/567228"><span id="translatedtitle">Validation testing of radioactive waste drum filter <span class="hlt">vents</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Weber, L.D.; Rahimi, R.S.; Edling, D.</p> <p>1997-08-01</p> <p>The minimum requirements for Drum Filter <span class="hlt">Vents</span> (DFVs) can be met by demonstrating conformance with the Waste Isolation Pilot Plant (WIPP) Trupact II Safety Assessment Report (SAR), and conformance with U.S. Federal shipping regulations 49 CFR 178.350, DOT Spec 7A, for <span class="hlt">Type</span> A packages. These together address a number of safety related performance parameters such as hydrogen diffusivity, flow related pressure drop, filtration efficiency and, separately, mechanical stability and the ability to prevent liquid water in-leakage. In order to make all metal DFV technology (including metallic filter medium) available to DOE sites, Pall launched a product development program to validate an all metal design to meet these requirements. Numerous problems experienced by DOE sites in the past came to light during this development program. They led us to explore enhancements to DFV design and performance testing addressing these difficulties and concerns. The result is a patented all metal DFV certified to all applicable regulatory requirements, which for the first time solves operational and health safety problems reported by DOE site personnel but not addressed by previous DFV`s. The new technology facilitates operations (such as manual, automated and semi-automated drum handling/redrumming), sampling, on-site storage, and shipping. At the same time, it upgrades filtration efficiency in configurations documented to maintain filter efficiency following mechanical stress. 2 refs., 2 figs., 10 tabs.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4677816','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4677816"><span id="translatedtitle">Seagrass biofilm communities at a naturally CO2-rich <span class="hlt">vent</span></span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Hassenrück, Christiane; Hofmann, Laurie C; Bischof, Kai; Ramette, Alban</p> <p>2015-01-01</p> <p>Seagrass meadows are a crucial component of tropical marine reef ecosystems. Seagrass plants are colonized by a multitude of epiphytic organisms that contribute to broadening the ecological role of seagrasses. To better understand how environmental changes like ocean acidification might affect epiphytic assemblages, the microbial community composition of the epiphytic biofilm of Enhalus acroides was investigated at a natural CO2 <span class="hlt">vent</span> in Papua New Guinea using molecular fingerprinting and next-generation sequencing of 16S and 18S rRNA genes. Both bacterial and eukaryotic epiphytes formed distinct communities at the CO2-impacted site compared with the control site. This site-related CO2 effect was also visible in the succession pattern of microbial epiphytes. We further found an increased relative sequence abundance of bacterial <span class="hlt">types</span> associated with coral diseases at the CO2-impacted site (Fusobacteria, Thalassomonas), whereas eukaryotes such as certain crustose coralline algae commonly related to healthy reefs were less diverse. These trends in the epiphytic community of E. acroides suggest a potential role of seagrasses as vectors of coral pathogens and may support previous predictions of a decrease in reef health and prevalence of diseases under future ocean acidification scenarios. PMID:25727314</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/23630523','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/23630523"><span id="translatedtitle">Biogeography of Persephonella in deep-sea hydrothermal <span class="hlt">vents</span> of the Western Pacific.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Mino, Sayaka; Makita, Hiroko; Toki, Tomohiro; Miyazaki, Junichi; Kato, Shingo; Watanabe, Hiromi; Imachi, Hiroyuki; Watsuji, Tomo-O; Nunoura, Takuro; Kojima, Shigeaki; Sawabe, Tomoo; Takai, Ken; Nakagawa, Satoshi</p> <p>2013-01-01</p> <p>Deep-sea hydrothermal <span class="hlt">vent</span> fields are areas on the seafloor with high biological productivity fueled by microbial chemosynthesis. Members of the Aquificales genus Persephonella are obligately chemosynthetic bacteria, and appear to be key players in carbon, sulfur, and nitrogen cycles in high temperature habitats at deep-sea <span class="hlt">vents</span>. Although this group of bacteria has cosmopolitan distribution in deep-sea hydrothermal ecosystem around the world, little is known about their population structure such as intraspecific genomic diversity, distribution pattern, and phenotypic diversity. We developed the multi-locus sequence analysis (MLSA) scheme for their genomic characterization. Sequence variation was determined in five housekeeping genes and one functional gene of 36 Persephonella hydrogeniphila strains originated from the Okinawa Trough and the South Mariana Trough (SNT). Although the strains share >98.7% similarities in 16S rRNA gene sequences, MLSA revealed 35 different sequence <span class="hlt">types</span> (ST), indicating their extensive genomic diversity. A phylogenetic tree inferred from all concatenated gene sequences revealed the clustering of isolates according to the geographic origin. In addition, the phenotypic clustering pattern inferred from whole-cell matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF/MS) analysis can be correlated to their MLSA clustering pattern. This study represents the first MLSA combined with phenotypic analysis indicative of allopatric speciation of deep-sea hydrothermal <span class="hlt">vent</span> bacteria. PMID:23630523</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012AGUFMOS13B1731M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012AGUFMOS13B1731M"><span id="translatedtitle">How Disturbance Influences Community Composition at Hydrothermal <span class="hlt">Vents</span>: a Theoretical Model of Macrofaunal Coexistence</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Miller, A. D.; Hsing, P.; Roxburgh, S. H.; Shea, K.; Fisher, C. R.</p> <p>2012-12-01</p> <p>Biological communities at spreading centers experience a continuum of disturbance regimes, with fast spreading ridges characterized by relatively frequent tectonic and magmatic events, and slow spreading ridges displaying more stable environmental conditions. We develop a theoretical model to show how disturbance (or lack thereof) can influence the composition of biological communities at hydrothermal <span class="hlt">vents</span>. Our model assumptions are based on empirical data, which show that macrofaunal species of interest (Riftia pachyptila, Bathymodiolus thermophilus, Calyptogena magnifica) establish in distinct microhabitats, based on availability of <span class="hlt">vent</span> fluids that nourish endosymbiotic chemoautotrophs. We focus on how these establishment strategies interact with species fecundity, and with disturbance frequency and intensity, to determine what <span class="hlt">types</span> of strategies can coexist in the system. We find that species must adopt sufficiently different fecundity-establishment strategies to coexist in the community, though strict tradeoffs between fecundity and establishment ability are not required. Additionally, we describe how the strategies that lead to coexistence depend on habitat availability and disturbance regime. Though other coexistence mechanisms may also play a role, our findings suggest why communities within a single biogeographic province may vary with spreading rate (as from N to S along the East Pacific Rise), and what strategies will allow coexistence under different disturbance regimes. Understanding how changes to disturbance regimes influence community composition is very important, as commercial mining interests are rapidly developing plans to exploit the rich mineral resources associated with hydrothermal <span class="hlt">vents</span> and their activities will change the disturbance regime.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=20050180833&hterms=1591&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3D%2526%25231591','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=20050180833&hterms=1591&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3D%2526%25231591"><span id="translatedtitle"><span class="hlt">Vented</span> Tank Resupply Experiment Demonstrated Vane Propellant Management Device for Fluid Transfer</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Chato, David J.</p> <p>1998-01-01</p> <p>The <span class="hlt">Vented</span> Tank Resupply Experiment (VTRE) flown on STS-77 confirmed the design approaches presently used in the development of vane-<span class="hlt">type</span> propellant management devices (PMD) for use in resupply and tank-<span class="hlt">venting</span> situations, and it provided the first practical demonstration of an autonomous fluid transfer system. All the objectives were achieved. Transfers were more stable than drop tower testing indicated. Liquid was retained successfully at the highest flow rate tested (2.73 gal/min), demonstrating that rapid fills could be achieved. Liquid-free <span class="hlt">vents</span> were achieved for two different tanks, although the flow rate was higher for the spherical tank (0.1591 cu ft/min) than for the tank with a short barrel section (0.0400 cu ft/min). Recovery from a thruster firing, which moved the liquid to the opposite end of the tank from the PMD, was achieved in 30 sec, showing that liquid rewicked more quickly into the PMD after thruster firing than pretest projections had predicted. In addition, researchers obtained great insights into the PMD behavior from the video footage provided, and discovered new considerations for future PMD designs that would not have been seen without this flight test.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li class="active"><span>22</span></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li><a href="#" onclick='return showDiv("page_24");'>24</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_22 --> <div id="page_23" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li class="active"><span>23</span></li> <li><a href="#" onclick='return showDiv("page_24");'>24</a></li> <li><a href="#" onclick='return showDiv("page_25");'>25</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="441"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4734175','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4734175"><span id="translatedtitle">Strong Ion Regulatory Abilities Enable the Crab Xenograpsus testudinatus to Inhabit Highly Acidified Marine <span class="hlt">Vent</span> Systems</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Hu, Marian Y.; Guh, Ying-Jey; Shao, Yi-Ta; Kuan, Pou-Long; Chen, Guan-Lin; Lee, Jay-Ron; Jeng, Ming-Shiou; Tseng, Yung-Che</p> <p>2016-01-01</p> <p>Hydrothermal <span class="hlt">vent</span> organisms have evolved physiological adaptations to cope with extreme abiotic conditions including temperature and pH. To date, acid-base regulatory abilities of <span class="hlt">vent</span> organisms are poorly investigated, although this physiological feature is essential for survival in low pH environments. We report the acid-base regulatory mechanisms of a hydrothermal <span class="hlt">vent</span> crab, Xenograpsus testudinatus, endemic to highly acidic shallow-water <span class="hlt">vent</span> habitats with average environment pH-values ranging between 5.4 and 6.6. Within a few hours, X. testudinatus restores extracellular pH (pHe) in response to environmental acidification of pH 6.5 (1.78 kPa pCO2) accompanied by an increase in blood HCO3- levels from 8.8 ± 0.3 to 31 ± 6 mM. Branchial Na+/K+-ATPase (NKA) and V-<span class="hlt">type</span> H+-ATPase (VHA), the major ion pumps involved in branchial acid-base regulation, showed dynamic increases in response to acidified conditions on the mRNA, protein and activity level. Immunohistochemical analyses demonstrate the presence of NKA in basolateral membranes, whereas the VHA is predominantly localized in cytoplasmic vesicles of branchial epithelial- and pillar-cells. X. testudinatus is closely related to other strong osmo-regulating brachyurans, which is also reflected in the phylogeny of the NKA. Accordingly, our results suggest that the evolution of strong ion regulatory abilities in brachyuran crabs that allowed the occupation of ecological niches in euryhaline, freshwater, and terrestrial habitats are probably also linked to substantial acid-base regulatory abilities. This physiological trait allowed X. testudinatus to successfully inhabit one of the world's most acidic marine environments. PMID:26869933</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/26869933','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/26869933"><span id="translatedtitle">Strong Ion Regulatory Abilities Enable the Crab Xenograpsus testudinatus to Inhabit Highly Acidified Marine <span class="hlt">Vent</span> Systems.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Hu, Marian Y; Guh, Ying-Jey; Shao, Yi-Ta; Kuan, Pou-Long; Chen, Guan-Lin; Lee, Jay-Ron; Jeng, Ming-Shiou; Tseng, Yung-Che</p> <p>2016-01-01</p> <p>Hydrothermal <span class="hlt">vent</span> organisms have evolved physiological adaptations to cope with extreme abiotic conditions including temperature and pH. To date, acid-base regulatory abilities of <span class="hlt">vent</span> organisms are poorly investigated, although this physiological feature is essential for survival in low pH environments. We report the acid-base regulatory mechanisms of a hydrothermal <span class="hlt">vent</span> crab, Xenograpsus testudinatus, endemic to highly acidic shallow-water <span class="hlt">vent</span> habitats with average environment pH-values ranging between 5.4 and 6.6. Within a few hours, X. testudinatus restores extracellular pH (pHe) in response to environmental acidification of pH 6.5 (1.78 kPa pCO2) accompanied by an increase in blood [Formula: see text] levels from 8.8 ± 0.3 to 31 ± 6 mM. Branchial Na(+)/K(+)-ATPase (NKA) and V-<span class="hlt">type</span> H(+)-ATPase (VHA), the major ion pumps involved in branchial acid-base regulation, showed dynamic increases in response to acidified conditions on the mRNA, protein and activity level. Immunohistochemical analyses demonstrate the presence of NKA in basolateral membranes, whereas the VHA is predominantly localized in cytoplasmic vesicles of branchial epithelial- and pillar-cells. X. testudinatus is closely related to other strong osmo-regulating brachyurans, which is also reflected in the phylogeny of the NKA. Accordingly, our results suggest that the evolution of strong ion regulatory abilities in brachyuran crabs that allowed the occupation of ecological niches in euryhaline, freshwater, and terrestrial habitats are probably also linked to substantial acid-base regulatory abilities. This physiological trait allowed X. testudinatus to successfully inhabit one of the world's most acidic marine environments. PMID:26869933</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/5892210','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/5892210"><span id="translatedtitle">Chimney related energy losses in oil-fired heating systems: Configuration effects and <span class="hlt">venting</span> alternatives</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Butcher, T.; McDonald, R.; Krajewski, R.; Batey, J.</p> <p>1990-12-01</p> <p>Conventional <span class="hlt">venting</span> systems for oil-fired residential heating equipment include the flue connector, a barometric damper, and the chimney. This <span class="hlt">venting</span> arrangement is directly responsible for some of the annual energy losses associated with these heating installations. In the work described in this report a study of the relevant characteristics of burners and dampers was done to permit these energy losses to be estimated as a function of the installation details. The purpose of this work is to determine the potential energy savings which might be realized from alternative <span class="hlt">venting</span> methods in a wide range of situations. The basic draft/flow characteristics of barometric dampers were measured using a flow tunnel arrangement under cold (no combustion) conditions. A range of damper diameters and draft settings were used. Off-cycle draft/flow relations for several burners and heating units with the burner ports sealed were also measured over a range of conditions. Recently, oil burners have become available which have significantly higher static pressure fans. The excess air level provided by these burners is much less sensitive to variations in draft and burners of this <span class="hlt">type</span> might be operated without a barometric damper. Burner fan performance curves for both high and low static pressure units have been measured. Flows through the heating unit and barometric damper flows have been calculated during the on- and off-cycle for a range of configurations as a function of outdoor temperature. The annual energy losses due to the <span class="hlt">venting</span> system were calculated using a bin method. The calculated flows were compared with available field data. To supplement the available data some additional field measurements were taken during this project and are described in this report. 19 refs., 42 figs., 7 tabs.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/884807','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/884807"><span id="translatedtitle">A Feasibility Study of H{sub 2}S Abatement by Incineration of Noncondensable Gases in <span class="hlt">Vented</span> Steam Flow from Davies-State 5206-1 Geothermal Steam Well, Geysers Geothermal Steam Field, Lake County, California</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p></p> <p>2006-08-25</p> <p>Determine feasibility of using an incineration-<span class="hlt">type</span> device to accomplish the required reduction in <span class="hlt">vent</span> steam H{sub 2}S content to meet ICAPCO rules. This approach is to be the only method considered in this feasibility study.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2016ChJOL.tmp...30Z&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2016ChJOL.tmp...30Z&link_type=ABSTRACT"><span id="translatedtitle">Effect of an escape <span class="hlt">vent</span> in accordion-shaped traps on the catch and size of Asian paddle crabs Charybdis japonica in an artificial reef area</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Zhang, Peng; Li, Chao; Li, Wentao; Zhang, Xiumei</p> <p>2016-02-01</p> <p>Accordion-shaped traps are widely used in China to catch the Asian paddle crab Charybdis japonica but traps of conventional design often catch juvenile crabs. A new <span class="hlt">type</span> of accordion-shaped trap with an escape <span class="hlt">vent</span> (L×W=4.3 cm×3.0 cm) was designed and a comparative study between the newly designed and conventional traps was performed in the artificial reef area of Zhuwang, Laizhou Bay, China from June to August 2012. The mean catch per unit effort (CPUE) of undersized crabs was significantly lower in the <span class="hlt">vented</span> traps than in the conventional traps (paired t -test, n=30, P<0.001), while the CPUE of marketable crabs was significantly higher in the <span class="hlt">vented</span> traps (paired t-test, n=30, P<0.001). The mean size of crabs (carapace length) caught in the <span class="hlt">vented</span> traps was significantly larger than in conventional traps (paired t-test, n=29, P<0.001). The ratio of undersized crabs was 35.05±2.57% in conventional traps and 12.53±0.69% in <span class="hlt">vented</span> traps (significantly lower, paired t-test, n=29, P<0.001). Therefore, a 4.3 cm×3.0 cm escape <span class="hlt">vent</span> was considered appropriate for C. japonica fishing in the artificial reef area. This finding will assist the development of more sustainable and efficient crab fishing methods using accordion-shaped traps.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/20228114','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/20228114"><span id="translatedtitle">Biogeography and biodiversity in sulfide structures of active and inactive <span class="hlt">vents</span> at deep-sea hydrothermal fields of the Southern Mariana Trough.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Kato, Shingo; Takano, Yoshinori; Kakegawa, Takeshi; Oba, Hironori; Inoue, Kazuhiko; Kobayashi, Chiyori; Utsumi, Motoo; Marumo, Katsumi; Kobayashi, Kensei; Ito, Yuki; Ishibashi, Jun-ichiro; Yamagishi, Akihiko</p> <p>2010-05-01</p> <p>The abundance, diversity, activity, and composition of microbial communities in sulfide structures both of active and inactive <span class="hlt">vents</span> were investigated by culture-independent methods. These sulfide structures were collected at four hydrothermal fields, both on- and off-axis of the back-arc spreading center of the Southern Mariana Trough. The microbial abundance and activity in the samples were determined by analyzing total organic content, enzymatic activity, and copy number of the 16S rRNA gene. To assess the diversity and composition of the microbial communities, 16S rRNA gene clone libraries including bacterial and archaeal phylotypes were constructed from the sulfide structures. Despite the differences in the geological settings among the sampling points, phylotypes related to the Epsilonproteobacteria and cultured hyperthermophilic archaea were abundant in the libraries from the samples of active <span class="hlt">vents</span>. In contrast, the relative abundance of these phylotypes was extremely low in the libraries from the samples of inactive <span class="hlt">vents</span>. These results suggest that the composition of microbial communities within sulfide structures dramatically changes depending on the degree of hydrothermal activity, which was supported by statistical analyses. Comparative analyses suggest that the abundance, activity and diversity of microbial communities within sulfide structures of inactive <span class="hlt">vents</span> are likely to be comparable to or higher than those in active <span class="hlt">vent</span> structures, even though the microbial community composition is different between these two <span class="hlt">types</span> of <span class="hlt">vents</span>. The microbial community compositions in the sulfide structures of inactive <span class="hlt">vents</span> were similar to those in seafloor basaltic rocks rather than those in marine sediments or the sulfide structures of active <span class="hlt">vents</span>, suggesting that the microbial community compositions on the seafloor may be constrained by the available energy sources. Our findings provide helpful information for understanding the biogeography, biodiversity and</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=2863450','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=2863450"><span id="translatedtitle">Biogeography and Biodiversity in Sulfide Structures of Active and Inactive <span class="hlt">Vents</span> at Deep-Sea Hydrothermal Fields of the Southern Mariana Trough▿ †</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Kato, Shingo; Takano, Yoshinori; Kakegawa, Takeshi; Oba, Hironori; Inoue, Kazuhiko; Kobayashi, Chiyori; Utsumi, Motoo; Marumo, Katsumi; Kobayashi, Kensei; Ito, Yuki; Ishibashi, Jun-ichiro; Yamagishi, Akihiko</p> <p>2010-01-01</p> <p>The abundance, diversity, activity, and composition of microbial communities in sulfide structures both of active and inactive <span class="hlt">vents</span> were investigated by culture-independent methods. These sulfide structures were collected at four hydrothermal fields, both on- and off-axis of the back-arc spreading center of the Southern Mariana Trough. The microbial abundance and activity in the samples were determined by analyzing total organic content, enzymatic activity, and copy number of the 16S rRNA gene. To assess the diversity and composition of the microbial communities, 16S rRNA gene clone libraries including bacterial and archaeal phylotypes were constructed from the sulfide structures. Despite the differences in the geological settings among the sampling points, phylotypes related to the Epsilonproteobacteria and cultured hyperthermophilic archaea were abundant in the libraries from the samples of active <span class="hlt">vents</span>. In contrast, the relative abundance of these phylotypes was extremely low in the libraries from the samples of inactive <span class="hlt">vents</span>. These results suggest that the composition of microbial communities within sulfide structures dramatically changes depending on the degree of hydrothermal activity, which was supported by statistical analyses. Comparative analyses suggest that the abundance, activity and diversity of microbial communities within sulfide structures of inactive <span class="hlt">vents</span> are likely to be comparable to or higher than those in active <span class="hlt">vent</span> structures, even though the microbial community composition is different between these two <span class="hlt">types</span> of <span class="hlt">vents</span>. The microbial community compositions in the sulfide structures of inactive <span class="hlt">vents</span> were similar to those in seafloor basaltic rocks rather than those in marine sediments or the sulfide structures of active <span class="hlt">vents</span>, suggesting that the microbial community compositions on the seafloor may be constrained by the available energy sources. Our findings provide helpful information for understanding the biogeography, biodiversity and</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015GGG....16.2661W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015GGG....16.2661W"><span id="translatedtitle">Geology, sulfide geochemistry and supercritical <span class="hlt">venting</span> at the Beebe Hydrothermal <span class="hlt">Vent</span> Field, Cayman Trough</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Webber, Alexander P.; Roberts, Stephen; Murton, Bramley J.; Hodgkinson, Matthew R. S.</p> <p>2015-09-01</p> <p>The Beebe <span class="hlt">Vent</span> Field (BVF) is the world's deepest known hydrothermal system, at 4960 m below sea level. Located on the Mid-Cayman Spreading Centre, Caribbean, the BVF hosts high temperature (˜401°C) "black smoker" <span class="hlt">vents</span> that build Cu, Zn and Au-rich sulfide mounds and chimneys. The BVF is highly gold-rich, with Au values up to 93 ppm and an average Au:Ag ratio of 0.15. Gold precipitation is directly associated with diffuse flow through "beehive" chimneys. Significant mass-wasting of sulfide material at the BVF, accompanied by changes in metal content, results in metaliferous talus and sediment deposits. Situated on very thin (2-3 km thick) oceanic crust, at an ultraslow spreading centre, the hydrothermal system circulates fluids to a depth of ˜1.8 km in a basement that is likely to include a mixture of both mafic and ultramafic lithologies. We suggest hydrothermal interaction with chalcophile-bearing sulfides in the mantle rocks, together with precipitation of Au in beehive chimney structures, has resulted in the formation of a Au-rich volcanogenic massive sulfide (VMS) deposit. With its spatial distribution of deposit materials and metal contents, the BVF represents a modern day analogue for basalt hosted, Au-rich VMS systems.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2014AGUFM.V14B..05T&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2014AGUFM.V14B..05T&link_type=ABSTRACT"><span id="translatedtitle">Inside the <span class="hlt">Vent</span> of the 2011-2012 Cordón Caulle Eruption, Chile: The Nature of a Rhyolitic Ash Plume Source</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Tuffen, H.; Castro, J. M.; Schipper, C. I.; Wadsworth, F. B.</p> <p>2014-12-01</p> <p>The 2011-2012 activity at Cordon Caulle has provided an unprecedented opportunity to observe a sustained explosive rhyolitic eruption. An initial 27 hour Plinian phase commenced on 4 June 2011, followed by ten months of hybrid explosive-effusive activity, which generated disruptive ≤6 km ash plumes. In January 2012 our close observations of the active <span class="hlt">vent</span>[1] revealed how episodic release of gas and ash from several sub-<span class="hlt">vents</span> on an incipient lava dome (Fig. 1b) merged to form a sustained ash plume. Sub-<span class="hlt">vents</span> ranged from metric point sources to arcuate fractures (>10 m) in the dome carapace. We visited the <span class="hlt">vent</span> in January 2014, and found two ~50 m-wide, rubble-strewn <span class="hlt">vent</span> areas adjacent to pancake-like obsidian domes, all within a breached, ~100 m-high tuff cone. <span class="hlt">Vent</span> areas consist of fractured obsidian lava strewn by loose, rotated lava blocks ≤5 m across. Prominent red fracture surfaces (Fig. 1 d,e) occur in both the in-situ lava and the blocky veneer; these closely correspond to the <span class="hlt">type</span> of sub-<span class="hlt">vents</span> observed in 2012[1]. They range from smooth, curviplanar surfaces extending over several m to complex smaller-scale surfaces that follow pre-existing cooling joints in the lava carapace. In-situ fracture surfaces display prominent, predominantly vertical grooves and impact marks, but negligible displacement. Surfaces are coated by μm-mm thick veneers of fine-grained ash, to which larger ash-coated clasts have adhered. Veneer thickness and sintering degree strongly decrease towards the upper carapace of the lava. SEM analysis of ash veneers reveals 1) a high proportion of sub-micron clasts, 2) strong clast sintering, 3) abundant ash aggregation textures spanning submicron-mm scales, and 4) local surface scouring and corrosion of glass and phenocrysts. During ash <span class="hlt">venting</span> the smallest particles are preferentially trapped on fracture surfaces and rapidly sintered, encouraging sub-<span class="hlt">vent</span> blockage. Extensive ash aggregation may have been electrostatically aided, with</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ars.usda.gov/research/publications/Publications.htm?seq_no_115=291906','TEKTRAN'); return false;" href="http://www.ars.usda.gov/research/publications/Publications.htm?seq_no_115=291906"><span id="translatedtitle">Three QTLs conferring resistance to kernel <span class="hlt">fissuring</span> in rice (Oryza sativa L.) identified by selective genotyping in two tropical japonica populations</span></a></p> <p><a target="_blank" href="http://www.ars.usda.gov/services/TekTran.htm">Technology Transfer Automated Retrieval System (TEKTRAN)</a></p> <p></p> <p></p> <p>Kernel <span class="hlt">fissures</span> caused by pre- or post-harvest stresses are the leading cause of breakage among milled rice, causing economic losses for producers, millers, and processors. Being an environmentally sensitive trait, it is difficult to reliably select for rice <span class="hlt">fissure</span> resistance among breeding progen...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.gpo.gov/fdsys/pkg/CFR-2012-title40-vol12/pdf/CFR-2012-title40-vol12-part63-subpartJJJ-app7.pdf','CFR2012'); return false;" href="https://www.gpo.gov/fdsys/pkg/CFR-2012-title40-vol12/pdf/CFR-2012-title40-vol12-part63-subpartJJJ-app7.pdf"><span id="translatedtitle">40 CFR Table 7 to Subpart Jjj of... - Group 1 Batch Process <span class="hlt">Vents</span> and Aggregate Batch <span class="hlt">Vent</span> Streams-Monitoring, Recordkeeping, and...</span></a></p> <p><a target="_blank" href="http://www.gpo.gov/fdsys/browse/collectionCfr.action?selectedYearFrom=2012&page.go=Go">Code of Federal Regulations, 2012 CFR</a></p> <p></p> <p>2012-07-01</p> <p>... Aggregate Batch <span class="hlt">Vent</span> Streams-Monitoring, Recordkeeping, and Reporting Requirements 7 Table 7 to Subpart JJJ... Standards for Hazardous Air Pollutant Emissions: Group IV Polymers and Resins Pt. 63, Subpt. JJJ, Table 7 Table 7 to Subpart JJJ of Part 63—Group 1 Batch Process <span class="hlt">Vents</span> and Aggregate Batch <span class="hlt">Vent</span>...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.gpo.gov/fdsys/pkg/CFR-2010-title40-vol11/pdf/CFR-2010-title40-vol11-part63-subpartJJJ-app7.pdf','CFR'); return false;" href="https://www.gpo.gov/fdsys/pkg/CFR-2010-title40-vol11/pdf/CFR-2010-title40-vol11-part63-subpartJJJ-app7.pdf"><span id="translatedtitle">40 CFR Table 7 to Subpart Jjj of... - Group 1 Batch Process <span class="hlt">Vents</span> and Aggregate Batch <span class="hlt">Vent</span> Streams-Monitoring, Recordkeeping, and...</span></a></p> <p><a target="_blank" href="http://www.gpo.gov/fdsys/browse/collectionCfr.action?selectedYearFrom=2010&page.go=Go">Code of Federal Regulations, 2010 CFR</a></p> <p></p> <p>2010-07-01</p> <p>... Aggregate Batch <span class="hlt">Vent</span> Streams-Monitoring, Recordkeeping, and Reporting Requirements 7 Table 7 to Subpart JJJ... Standards for Hazardous Air Pollutant Emissions: Group IV Polymers and Resins Pt. 63, Subpt. JJJ, Table 7 Table 7 to Subpart JJJ of Part 63—Group 1 Batch Process <span class="hlt">Vents</span> and Aggregate Batch <span class="hlt">Vent</span>...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3211767','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3211767"><span id="translatedtitle"><span class="hlt">Venting</span> during prophylactic nailing for femoral metastases: current orthopedic practice</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Dalgorf, Dustin; Borkhoff, Cornelia M.; Stephen, David J.G.; Finkelstein, Joel; Kreder, Hans J.</p> <p>2003-01-01</p> <p>Introduction Reamed intramedullary nailing, recommended for impending fracture of a femur weakened by bone metastases, causes a rise in intramedullary pressure and increases the risk of a fat embolism syndrome. The pressure can be equalized by the technique of <span class="hlt">venting</span> — drilling a hole into the distal cortex of the femur. Our objective was to study the current practice of orthopedic surgeons in Ontario with respect to <span class="hlt">venting</span> during prophylactic intramedullary nailing for an impending femoral fracture due to bone metastases. Methods We mailed a questionnaire to all orthopedic surgeons from the Province of Ontario listed in the 1999 Canadian Medical Directory or on the Canadian Orthopaedic Association membership list, asking if they <span class="hlt">vent</span> when prophylactically nailing an impending pathologic femoral fracture. The responses were modelled as a function of surgeon volume and year of graduation. Results Of the 415 surveys mailed, 223 (54%) surgeons responded. Of these, 81% reported having prophylactically treated a femoral metastatic lesion during the previous year; 67% treated 1 to 3 metastatic lesions and 14% treated more than 3; 19% did not treat a metastatic femoral lesion prophylactically. Over two-thirds of surgeons had never considered <span class="hlt">venting</span>, whereas one-third always or sometimes <span class="hlt">vented</span> the femoral canal. More recent graduates were 3 times more likely to <span class="hlt">vent</span> than earlier (before 1980) graduates (odds ratio [OR] = 3.2, 95% confidence interval [CI] 1.6–6.5) as were those who treat a greater number of impending fractures (OR = 1.4, 95% CI 1.1–1.7). Conclusions Although there is a theoretical rationale for routine <span class="hlt">venting</span>, there is disagreement among Ontario orthopedic surgeons regarding the use of this technique during prophylactic nailing for femoral metastatic lesions. Prospective evidence will be required to warrant a change in the standard of care. PMID:14680349</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014JGRB..119.4708G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014JGRB..119.4708G"><span id="translatedtitle">Morphology and dynamics of explosive <span class="hlt">vents</span> through cohesive rock formations</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Galland, O.; Gisler, G. R.; Haug, Ø. T.</p> <p>2014-06-01</p> <p>Shallow explosive volcanic processes, such as kimberlite volcanism and phreatomagmatic and phreatic activity, produce volcanic <span class="hlt">vents</span> exhibiting a wide variety of morphologies, including vertical pipes and V-shaped <span class="hlt">vents</span>. In this study we report on experimental and numerical models designed to capture a range of <span class="hlt">vent</span> morphologies in an eruptive system. Using dimensional analysis, we identified key governing dimensionless parameters, in particular the gravitational stress-to-fluid pressure ratio (Π2 = P/ρgh) and the fluid pressure-to-host rock strength ratio (Π3 = P/C). We used combined experimental and numerical models to test the effects of these parameters. The experiments were used to test the effect of Π2 on <span class="hlt">vent</span> morphology and dynamics. A phase diagram demonstrates a separation between two distinct morphologies, with vertical structures occurring at high values of Π2 and diagonal ones at low values of Π2. The numerical simulations were used to test the effect of Π3 on <span class="hlt">vent</span> morphology and dynamics. In the numerical models we see three distinct morphologies: vertical pipes are produced at high values of Π3, diagonal pipes at low values of Π3, and horizontal sills at intermediate values of Π3. Our results show that vertical pipes form by plasticity-dominated yielding in high-energy systems (high Π2 and Π3), whereas diagonal and horizontal <span class="hlt">vents</span> dominantly form by fracturing in lower energy systems (low Π2 and Π3). Although our models are two-dimensional, they suggest that circular pipes result from plastic yielding of the host rock in a high-energy regime, whereas V-shaped volcanic <span class="hlt">vents</span> result from fracturing of the host rock in lower energy systems.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2008epsc.conf..115L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2008epsc.conf..115L"><span id="translatedtitle">Morphology of cone-fields in SW Elysium Planitia - Traces of hydrothermal <span class="hlt">venting</span> on Mars?</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Lanz, J. K.; Saric, M. B.</p> <p>2008-09-01</p> <p> wide. There are distinct morphological changes both within the band from north to south and along the band from east to west (Fig. 2). The cones are mostly circular but elongated, irregular forms are common. They are of varying size with basal diameters ranging from 20 to 200 meters, though most (single) cones have basal diameters below 100 meters. The heights of the cones are difficult to determine as their sizes are far below the resolution limits of either MOLA or HRSC stereo data, yet photoclinometric calculations have given approximate heights between ~ 10 up to several dozens of meters. Often the cones show hardly any elevation above the surroundings (e.g. Fig. 2c, e or f). Most of the APCs have steep convex flanks and large summit pits with diameters at least half as wide as their bases. The overall morphology of the cones changes from S to N with distance from the APF and from E to W along the edges of the APF. Toward the south, close to the strongly eroded borders of the APF, broad ridges and elongated domes are dominant. They form a narrow band approximately 2 km wide. The ridges and domes are a few dozen to several hundred meters long and between 10 to 50 meters wide and show numerous cracks and <span class="hlt">fissures</span>. They are often topped by small cones, elongated pits and remnants of APF sediments. Further north follows a rather abrupt transition from the ridged area to more cone-dominated regions. Here single cones are prevalent with a more random distribution. Their number decreases rapidly with increasing distance from the APF and approximately 3 km off the southern edge of the APF no further cones are found. Hydrothermal <span class="hlt">venting</span> on Mars? Morphology and stratigraphic relationships indicate that the cones are young and that they have, at least in places, developed inside the APF complex. APF remnants can be found covering the central pits of cones and APF units have been tilted and eroded by coneforming processes. Furthermore, cones are mainly found inside a narrow</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4705711','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4705711"><span id="translatedtitle">Herpes zoster ophthalmicus presenting as orbital abscess along with superior orbital <span class="hlt">fissure</span> syndrome: A case report</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Lavaju, Poonam; Badhu, Badri Prasad; Shah, Sangeeta</p> <p>2015-01-01</p> <p>Orbital abscess and superior orbital <span class="hlt">fissure</span> syndrome (SOFS) are rare manifestations of herpes zoster ophthalmicus. Herein, we report a case of orbital abscess along with SOFS in a 2.5-year-old-male child secondary to herpes zoster infection. He presented with a 5-day history of proptosis and ptosis of the right eye that had been preceded by vesicular eruptions on the right forehead and scalp. Computed tomography scan of the head and orbit showed orbital abscess and right cavernous sinus thrombosis. A diagnosis of orbital abscess with SOFS secondary to herpes infection was made. The condition subsequently improved following antiviral therapy, intravenous vancomycin and amikacin, and oral corticosteroids. PMID:26632131</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4125581','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4125581"><span id="translatedtitle">Enamel pretreatment with Er:YAG laser: effects on the microleakage of <span class="hlt">fissure</span> sealant in fluorosed teeth</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Kianimanesh, Nasrin; Shayeghi, Bahareh</p> <p>2014-01-01</p> <p>Objectives The purpose of this in vitro study was to evaluate the microleakage and penetration of <span class="hlt">fissure</span> sealant in permanent molar teeth with fluorosis after pretreatment of the occlusal surface. Materials and Methods A total of 120 third molars with mild dental fluorosis were randomly divided into 6 groups (n = 20). The tooth surfaces were sealed with an unfilled resin <span class="hlt">fissure</span> sealant (FS) material. The experimental groups included: 1) phosphoric acid etching (AE) + FS (control); 2) AE + One-Step Plus (OS, Bisco) + FS; 3) bur + AE + FS; 4) bur + AE + OS + FS; 5) Er:YAG laser + AE + FS; and 6) Er:YAG laser + AE + OS + FS. After thermocycling, the teeth were immersed in 0.5% fuchsin and sectioned. Proportions of mircoleakage (PM) and unfilled area (PUA) were measured by digital microscope. Results Overall, there were significant differences among all groups in the PM (p = 0.00). Group 3 showed the greatest PM, and was significantly different from groups 2 to 6 (p < 0.05). Group 6 showed the lowest PM. Pretreatment with Er:YAG with or without adhesive led to less PM than bur pretreatment. There were no significant differences among groups in PUA. Conclusions Conventional acid etching provided a similar degree of occlusal seal in teeth with fluorosis compared to those pretreated with a bur or Er:YAG laser. Pretreatment of pits and <span class="hlt">fissures</span> with Er:YAG in teeth with fluorosis may be an alternative method before <span class="hlt">fissure</span> sealant application. PMID:25110641</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19900009170','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19900009170"><span id="translatedtitle">Zero-Gravity Vortex <span class="hlt">Vent</span> and PVT Gaging System</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Downey, M. G.; Trevathan, J. T.</p> <p>1989-01-01</p> <p>Space Station and satellite reservicing will require the ability to <span class="hlt">vent</span> gas on orbit from liquid supply or storage tanks and to gage liquid quantity under microgravity conditions. In zero gravity, (zero-g) the vortex <span class="hlt">vent</span> is capable of <span class="hlt">venting</span> gas from a tank of liquid containing gas randomly distributed as bubbles. The concept uses a spinning impeller to create centrifugal force inside a vortex tube within a tank. This creates a gas pocket and forces the liquid through a venturi and back into the tank. Gas is then <span class="hlt">vented</span> from the gas pocket through a liquid detector and then out through an exhaust port. If the liquid detector senses liquid in the <span class="hlt">vent</span> line, the fluid is directed to the low-pressure port on the venturi and is returned to the tank. The advantages of this system is that it has no rotating seals and is compatible with most corrosive and cryogenic fluids. A prototype was designed and built at the NASA Johnson Space Center and flown on the KC-135 zero-g aircraft. During these test flights, where microgravity conditions are obtained for up to 30 sec, the prototype demonstrated that less than 0.10 percent of the volume of fluid <span class="hlt">vented</span> was liquid when the tank was half full of liquid. The pressure volume temperature (PVT) gaging system is used in conjunction with the vortex <span class="hlt">vent</span> to calculate the amount of liquid remaining in a tank under microgravity conditions. The PVT gaging system is used in conjunction with the vortex <span class="hlt">vent</span> to gage liquid quantity in zero or low gravity. The system consists of a gas compressor, accumulator, and temperature and pressure instrumentation. To measure the liquid in a tank a small amount of gas is <span class="hlt">vented</span> from the tank to the compressor and compressed into the accumulator. Pressure and temperature in the tank and accumulator are measured before and after the gas transfer occurs. Knowing the total volume of the tank, the volume of the accumulator, the volume of the intermediate lines, and initial and final pressures and</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2008AGUFM.V41B2076G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2008AGUFM.V41B2076G"><span id="translatedtitle">Bacterial Diets of Primary Consumers at Hydrothermal <span class="hlt">Vents</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Govenar, B.; Shank, T. M.</p> <p>2008-12-01</p> <p>Chemical energy produced by mixing hydrothermal fluids and seawater supports dense biological communities on mid-ocean ridges. The base of the food web at deep-sea hydrothermal <span class="hlt">vents</span> is formed by chemolithoautotrophic bacteria that use the energy from the oxidation of reduced chemicals to fix inorganic carbon into simple sugars. With the exception of a few species that have chemolithoautotropic bacterial symbionts, most of the <span class="hlt">vent</span>-endemic macrofauna are heterotrophs that feed on free-living bacteria, protists, and other invertebrates. The most abundant and diverse group of primary consumers in hydrothermal <span class="hlt">vent</span> communities belong to the Gastropoda, particularly the patellomorph limpets. Gastropod densities can be as high as 2000 individuals m-2, and there can be as many as 13 species of gastropods in a single aggregation of the siboglinid tubeworm Riftia pachyptila and more than 40 species along the East Pacific Rise. Some gastropods are ubiquitous and others are found in specific microhabitats, stages of succession, or associated with different foundation species. To determine the mechanisms of species coexistence (e.g. resource partitioning or competition) among hydrothermal <span class="hlt">vent</span> primary consumers and to track the flow of energy in hydrothermal <span class="hlt">vent</span> communities, we employed molecular genetic techniques to identify the gut contents of four species of co-occurring hydrothermal <span class="hlt">vent</span> gastropods, Eulepetopsis vitrea, Lepetodrilus elevatus, Lepetodrilus ovalis and Lepetodrilus pustulosus, collected from a single diffuse-flow hydrothermal <span class="hlt">vent</span> site on the East Pacific Rise. Unique haplotypes of the 16S gene that fell among the epsilon-proteobacteria were found in the guts of every species, and two species had gut contents that were similar only to epsilon-proteobacteria. Two species had gut contents that also included haplotypes that clustered with delta-proteobacteria, and one species had gut contents that clustered with alpha- proteobacteria. Differences in the diets</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2004QSRv...23.1151H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2004QSRv...23.1151H"><span id="translatedtitle">Stratigraphy and geochronology of pitfall accumulations in caves and <span class="hlt">fissures</span>, Bermuda</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Hearty, Paul J.; Olson, Storrs L.; Kaufman, Darrell S.; Edwards, R. Lawrence; Cheng, Hai</p> <p>2004-05-01</p> <p>Deep fractures ("<span class="hlt">fissures</span>") and avens ("skylights") in limestone cave roofs create natural traps for sediments and biota. <span class="hlt">Fissures</span> fill quickly with surface sediment and organisms soon after opening. Debris cones are formed as materials fall, wash, or drift on air through openings in cave skylights. Such deposits in Admiral's and Grand Canyon Cave, Bermuda contain distinct beds and are composed of mixtures of sediment and charcoal, together with fossils of land snails, crabs, birds, reptiles, and bats. The "pitfall" accumulations were periodically sealed over by calcite flowstone. A stratigraphic record of surface activity and fauna through both glacial and interglacial periods has been preserved. The succession also provides an ideal setting in which to compare several geochronological methods. Calibrated 14C ages on charcoal and shells provide dated horizons at 1600, 12,800, and about 35,000 14C yr BP. Thermal ionization mass spectrometric (TIMS) ages on several flowstone layers constrain the entire sequence in the Admiral's Cave sequence between 126,300±900 yr (Termination II) and historical times. A continuous relative-age record generated by amino acid epimerization (AAE) geochronology ( D-alloisoleucine/ L-isoleucine or aIle/Ile) on the pulmonate land gastropod Poecilozonites verifies the biostratigraphy, reveals a minimal degree of mixing between stratigraphic units, and establishes an independent temporal link between the subterranean and subaerial deposits of Bermuda. This convergence between stratigraphy and geochronology yields a precisely dated succession from the oceanic island of Bermuda, and thus presents a unique opportunity to assess the rates and processes of evolutionary and climate change during that interval.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li class="active"><span>23</span></li> <li><a href="#" onclick='return showDiv("page_24");'>24</a></li> <li><a href="#" onclick='return showDiv("page_25");'>25</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_23 --> <div id="page_24" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li class="active"><span>24</span></li> <li><a href="#" onclick='return showDiv("page_25");'>25</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="461"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2003JPhy4.106...69A','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2003JPhy4.106...69A"><span id="translatedtitle"><span class="hlt">Fissuration</span> en relaxation des aciers inoxydables austénitiques au voisinage des soudures</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Auzoux, Q.; Allais, L.; Gourgues, A. F.; Pineau, A.</p> <p>2003-03-01</p> <p>Des <span class="hlt">fissures</span> intergranulaires peuvent se développer au voisinage des soudures des aciers inoxydables austénitiques lorsqu'ils sont réchauffés dans le domaine de température compris entre 500^{circ}C et 700^{circ}C. A ces températures, les contraintes résiduelles post-soudage se relaxent par déformation viscoplastique. Il peut arriver que ces zones proches de la soudure soient tellement fragiles, qu'elles ne puissent accommoder cette faible déformation. Afin de préciser quelles peuvent être les modifications microstructurales qui conduisent à une telle fragilisation, on a examiné les microstructures de ces zones et révélé ainsi un écrouissage résiduel, responsable d'une forte élévation de la dureté. On a pu reproduire par hypertrempe puis laminage entre 400^{circ}C et 600^{circ}C une microstructure similaire. Des essais mécaniques (traction, fluage, relaxation, sur éprouvettes lisses et pré-<span class="hlt">fissur</span>ées) ont été réalisés à 550^{circ}C et à 600^{circ}C sur ces zones affectées simulées et sur un état de référence hypertrempé. Ils ont montré que l'écrouissage diminuait la ductilité dans le domaine de rupture intergranulaire, sans modifier qualitativement le mécanisme d'endommagement. Pendant la pré-déformation les incompatibilités de déformation entre grains conduiraient à l'existence de contraintes locales élevées qui favoriseraient la germination des cavités intergranulaires.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19830061540&hterms=steam+water&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3Dsteam%2Bwater','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19830061540&hterms=steam+water&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3Dsteam%2Bwater"><span id="translatedtitle">Steam chugging analysis in single-<span class="hlt">vent</span> vapor injection</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Lee, C. K. B.; Chan, C. K.</p> <p>1982-01-01</p> <p>A complete cycle of the periodic steam chugging phenomenon is analyed. Steam velocity and pressure variations in the <span class="hlt">vent</span> are described by one-dimensional conservation equations. This is coupled either to the water slug model when water is in the <span class="hlt">vent</span>, or, the infinite pool spherical bubble model at the <span class="hlt">vent</span> exit during bubble growth. An isolated spherical bubble model is used for computing the collapse pressures. Comparisons of the model predictions with the UCLA 1/12-scale and the Japan 1/6-scale data indicate that the <span class="hlt">vent</span>-pipe model predicts the <span class="hlt">vent</span>-clearing times and the bubble growth times well. In addition, the predicted maximum chugging heights compared well with those measured in the Japan data. On bubble collapse pressures, the comparison with the spherical bubble model predictions is only fair. The model generally overpredicts the magnitude of the spikes. On examining the effects of pool subcooling and steam mass flux, general agreement is found between the predicted trends and those measured.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://pubs.er.usgs.gov/publication/70028504','USGSPUBS'); return false;" href="http://pubs.er.usgs.gov/publication/70028504"><span id="translatedtitle">A ubiquitous thermoacidophilic archaeon from deep-sea hydrothermal <span class="hlt">vents</span></span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Reysenbach, A.-L.; Liu, Yajing; Banta, A.B.; Beveridge, T.J.; Kirshtein, J.D.; Schouten, S.; Tivey, M.K.; Von Damm, K. L.; Voytek, M.A.</p> <p>2006-01-01</p> <p>Deep-sea hydrothermal <span class="hlt">vents</span> are important in global biogeochemical cycles, providing biological oases at the sea floor that are supported by the thermal and chemical flux from the Earth's interior. As hot, acidic and reduced hydrothermal fluids mix with cold, alkaline and oxygenated sea water, minerals precipitate to form porous sulphide-sulphate deposits. These structures provide microhabitats for a diversity of prokaryotes that exploit the geochemical and physical gradients in this dynamic ecosystem. It has been proposed that fluid pH in the actively <span class="hlt">venting</span> sulphide structures is generally low (pH < 4.5), yet no extreme thermoacidophile has been isolated from <span class="hlt">vent</span> deposits. Culture-independent surveys based on ribosomal RNA genes from deep-sea hydrothermal deposits have identified a widespread euryarchaeotal lineage, DHVE2 (deep-sea hydrothermal <span class="hlt">vent</span> euryarchaeotic 2). Despite the ubiquity and apparent deep-sea endemism of DHVE2, cultivation of this group has been unsuccessful and thus its metabolism remains a mystery. Here we report the isolation and cultivation of a member of the DHVE2 group, which is an obligate thermoacidophilic sulphur- or iron-reducing heterotroph capable of growing from pH 3.3 to 5.8 and between 55 and 75??C. In addition, we demonstrate that this isolate constitutes up to 15% of the archaeal population, providing evidence that thermoacidophiles may be key players in the sulphur and iron cycling at deep-sea <span class="hlt">vents</span>. ?? 2006 Nature Publishing Group.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/16871216','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/16871216"><span id="translatedtitle">A ubiquitous thermoacidophilic archaeon from deep-sea hydrothermal <span class="hlt">vents</span>.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Reysenbach, Anna-Louise; Liu, Yitai; Banta, Amy B; Beveridge, Terry J; Kirshtein, Julie D; Schouten, Stefan; Tivey, Margaret K; Von Damm, Karen L; Voytek, Mary A</p> <p>2006-07-27</p> <p>Deep-sea hydrothermal <span class="hlt">vents</span> are important in global biogeochemical cycles, providing biological oases at the sea floor that are supported by the thermal and chemical flux from the Earth's interior. As hot, acidic and reduced hydrothermal fluids mix with cold, alkaline and oxygenated sea water, minerals precipitate to form porous sulphide-sulphate deposits. These structures provide microhabitats for a diversity of prokaryotes that exploit the geochemical and physical gradients in this dynamic ecosystem. It has been proposed that fluid pH in the actively <span class="hlt">venting</span> sulphide structures is generally low (pH < 4.5), yet no extreme thermoacidophile has been isolated from <span class="hlt">vent</span> deposits. Culture-independent surveys based on ribosomal RNA genes from deep-sea hydrothermal deposits have identified a widespread euryarchaeotal lineage, DHVE2 (deep-sea hydrothermal <span class="hlt">vent</span> euryarchaeotic 2). Despite the ubiquity and apparent deep-sea endemism of DHVE2, cultivation of this group has been unsuccessful and thus its metabolism remains a mystery. Here we report the isolation and cultivation of a member of the DHVE2 group, which is an obligate thermoacidophilic sulphur- or iron-reducing heterotroph capable of growing from pH 3.3 to 5.8 and between 55 and 75 degrees C. In addition, we demonstrate that this isolate constitutes up to 15% of the archaeal population, providing evidence that thermoacidophiles may be key players in the sulphur and iron cycling at deep-sea <span class="hlt">vents</span>. PMID:16871216</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/24862554','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/24862554"><span id="translatedtitle">Spatial patterns of Aquificales in deep-sea <span class="hlt">vents</span> along the Eastern Lau Spreading Center (SW Pacific).</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Ferrera, Isabel; Banta, Amy B; Reysenbach, Anna-Louise</p> <p>2014-09-01</p> <p>The microbial diversity associated with actively <span class="hlt">venting</span> deep-sea hydrothermal deposits is tightly connected to the geochemistry of the hydrothermal fluids. Although the dominant members of these deposits drive the structure of the microbial communities, it is less well understood whether the lower abundance groups are as closely connected to the geochemical milieu, or driven perhaps by biotic factors such as microbial community interactions. We used the natural geochemical gradients that exist in the back-arc basin, Eastern Lau Spreading Center and Valu-Fa Ridge (ELSC/VFR) in the Southwestern Pacific, to explore whether the chemolithotrophic Aquificales are influenced by geographical location, host-rock of the <span class="hlt">vent</span> field or deposit <span class="hlt">type</span>. Using a combination of cloning, DNA fingerprinting (DGGE) and enrichment culturing approaches, all genera of this order previously described at marine <span class="hlt">vents</span> were detected, i.e., Desulfurobacterium, Thermovibrio, Aquifex, Hydrogenivirga, Persephonella and Hydrogenothermus. The comparison between clone libraries and DGGE showed similar patterns of distribution of different Aquificales whereas results differed for the enrichment cultures that were retrieved. However, the use of cultivation-based and -independent methods did provide complementary phylogenetic diversity overview of the Aquificales in these systems. Together, this survey revealed that the ELSC/VFR contains some of the largest diversity of Aquificales ever reported at a deep-sea <span class="hlt">vent</span> area, that the diversity patterns are tied to the geography and geochemistry of the system, and that this geochemical diverse back-arc basin may harbor new members of the Aquificales. PMID:24862554</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=183184','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=183184"><span id="translatedtitle">Evidence for Methylotrophic Symbionts in a Hydrothermal <span class="hlt">Vent</span> Mussel (Bivalvia: Mytilidae) from the Mid-Atlantic Ridge †</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Cavanaugh, Colleen M.; Wirsen, Carl O.; Jannasch, H. W.</p> <p>1992-01-01</p> <p>Symbioses between chemolithoautotrophic bacteria and the major macrofaunal species found at hydrothermal <span class="hlt">vents</span> have been reported for numerous sites in the Pacific Ocean. We present microscopical and enzymatic evidence that methylotrophic bacteria occur as intracellular symbionts in a new species of mytilid mussel discovered at the Mid-Atlantic Ridge hydrothermal <span class="hlt">vents</span>. Two distinct ultrastructural <span class="hlt">types</span> of gram-negative procaryotic symbionts were observed within gill epithelial cells by transmission electron microscopy: small coccoid or rod-shaped cells and larger coccoid cells with stacked intracytoplasmic membranes typical of methane-utilizing bacteria. Methanol dehydrogenase, an enzyme diagnostic of methylotrophs, was detected in the mytilid gills, while tests for ribulose-1,5-bisphosphate carboxylase, the enzyme diagnostic of autotrophy via the Calvin cycle, were negative. Stable carbon isotope values (δ13C) of mytilid tissue (−32.7 and −32.5% for gill and foot tissues, respectively) fall within the range of values reported for Pacific <span class="hlt">vent</span> symbioses but do not preclude the use of <span class="hlt">vent</span>-derived methane reported to be isotopically heavy relative to biogenically produced methane. Images PMID:16348816</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2016EGUGA..18.4504G&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2016EGUGA..18.4504G&link_type=ABSTRACT"><span id="translatedtitle">Shift from magmatic to phreatomagmatic explosion controlled by the evolution of lateral <span class="hlt">fissure</span> eruption in Suoana Crater, Miyakejima</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Geshi, Nobuo; Nemeth, Karoly; Noguchi, Rina; Oikawa, Teruki</p> <p>2016-04-01</p> <p>Combined analysis of the proximal deposit and exposed feeder-diatreme structure of the Suoana Crater of Miyakejima reveals the process of magma-water interaction controlled by the evolution of lateral <span class="hlt">fissure</span> eruption in a stratovolcanic edifice. The Suoana Crater, an oval maar with 400 x 300 m across is one of the craters of the Suoana-Kazahaya crater chain which is formed during a <span class="hlt">fissure</span> eruption in the 7th Century. The eruption <span class="hlt">fissure</span> extends ~3 km from the summit area (~700 m asl) to the lower-flank area (~200m asl). The eruption <span class="hlt">fissure</span> consists of upper maar-chain (>450 m asl) and lower scora-cone chain. As the wall of the 2000 AD caldera truncated at near the center of the Suoana Crater, the vertical section of the feeder dike - diatreme - maar system of the Suoana Crater is exposed in the caldera wall (Geshi et al., 2011). The ejected materials from the Suoana crater indicate the transition of eruption style from magmatic to phreatomagmatic. The juvenile clasts in the lower half of the deposit exhibit spatter-like shape, indicating the typical deposit from a vigorous fire fountain. Contrary, the juvenile clasts in the upper half are less vesiculated and exhibit cauliflower-shape, indicating the typical phreatomagmatic activity. This transition indicates that the magma-water interaction started at the middle of the eruption. Judging from the ratio of the thickness of the lower and upper parts, the contrast of the content of juvenile clasts, and bulk density of the deposit, the total ejected volume of magma is larger in the lower part compare to the upper part. The transition from magmatic to phreatomagmatic occurred only in the upper half of the eruption <span class="hlt">fissure</span>, including the Suoana crater, whereas the lower half of the <span class="hlt">fissure</span> continued dry magmatic eruption throughout their activity. The limited distribution of phreatomagmatic activity can be resulted by the magma extraction from the upper feeder dike system to the lower eruption <span class="hlt">fissure</span> as it</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015EGUGA..1715136M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015EGUGA..1715136M"><span id="translatedtitle">Volcanic field elongation, <span class="hlt">vent</span> distribution and tectonic evolution of continental rift: The Main Ethiopian Rift example</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Mazzarini, Francesco; Le Corvec, Nicolas; Isola, Ilaria; Favalli, Massimiliano</p> <p>2015-04-01</p> <p>Magmatism and faulting operate in continental rifts and interact at a variety of scales, however their relationship is complex. The African rift, being the best example for both active continental rifting and magmatism, provides the ideal location to study the interplay between the two mechanisms. The Main Ethiopian Rift (MER), which connects the Afar depression in the north with the Turkana depression and Kenya Rift to the south, consists of two distinct systems of normal faults and its floor is scattered with volcanic fields formed by tens to several hundreds monogenetic, generally basaltic, small volcanoes and composite volcanoes and small calderas. The distribution of <span class="hlt">vents</span> defines the overall shape of the volcanic field. Previous work has shown that the distribution of volcanic <span class="hlt">vents</span> and the shape of a field are linked to its tectonic environment and its magmatic system. In order to distinguish the impact of each mechanism, we analyzed four volcanic fields located at the boundary between the central and northern MER, three of them (Debre Zeyit, Wonji and Kone) grew in the rift valley and one (Akaki) on the western rift shoulder. The elongation and shape of the fields were analyzed based on their <span class="hlt">vent</span> distribution using the Principal Component Analysis (PCA), the <span class="hlt">Vent-to-Vent</span> Distance (VVD), and the two dimensional symmetric Gaussian kernel density estimate methods. We extracted from these methods several parameters characterizing the spatial distribution of points (e.g., eccentricity (e), eigenvector index (evi), angular dispersion (Da)). These parameters allow to define at least three <span class="hlt">types</span> of shape for volcanic fields: strong elongate (line and ellipse), bimodal/medium elongate (ellipse) and dispersed (circle) shapes. Applied to the natural example, these methods well differentiate each volcanic field. For example, the elongation of the field increases from shoulder to rift axis inversely to the angular dispersion. In addition, the results show that none of</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4279319','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4279319"><span id="translatedtitle">Comparative study of Ksharasutra suturing and Lord's anal dilatation in the management of Parikartika (chronic <span class="hlt">fissure</span>-in-ano)</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Dudhamal, Tukaram S.; Baghel, Madhav Singh; Bhuyan, Chaturbhuja; Gupta, Sanjay Kumar</p> <p>2014-01-01</p> <p>Background: Parikartika resembles <span class="hlt">fissure</span>-in-ano which is very common among all ano-rectal disorders. In Ayurvedic texts, Parikartika is described as a complication of Vamana and Virechana as well as complication of Atisara. Ksharasutra was proved successful in the management of fistula-in-ano, piles, and there is a need to try its efficacy in <span class="hlt">fissure</span>-in-ano. Aim: To evaluate the role of Ksharasutra suturing (KSS) in <span class="hlt">fissure</span> bed in chronic <span class="hlt">fissure</span>-in-ano. Materials and Methods: Total 100 patients of chronic <span class="hlt">fissure</span>-in-ano were selected and randomly divided into two groups (50 in each group). In group-A, patients were undergone by KSS; while in patients of Group-B Lord's anal dilatation followed by KSS was done under spinal anesthesia. The KSS was done once and after slough out of Ksharasutra, the wound was treated for 4 weeks and assessment of the result was done on the basis of gradation adopted. Results: The pain relief on 14th day in Group-A was 86% while in Group-B 100% was observed. As on 7th day in Group-A, oozing was stopped in 68% patients, while in Group-B, oozing was stopped in 82% patients. On 21st day, Group-B showed more healing (85%) as compared to Group-A (69%). In this study 68% of patients were cured. Conclusion: In Group-B (KSS with Lord's anal dilatation) patients were cured early as compared to patients of Group-A (KSS alone). PMID:25558158</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1998DSRII..45..319V','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1998DSRII..45..319V"><span id="translatedtitle">Naked in toxic fluids: A nudibranch mollusc from hydrothermal <span class="hlt">vents</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Valdés, Ángel; Bouchet, Philippe</p> <p>1998-01-01</p> <p>A new species of the nudibranch genus Dendronotus (Mollusca, Opisthobranchia) is reported from a hydrothermal <span class="hlt">vent</span> at the Lucky Strike area, on the Mid-Atlantic Ridge. This is the first species of nudibranch recorded with certainty from a <span class="hlt">vent</span> site. Other species of Dendronotus are distributed in temperate waters on the continental shelf of the northern hemisphere. Two factors that probably account for the occurrence of a nudibranch in this hydrothermal field are that the Lucky Strike area presents potential hydroid prey, and that nudibranchs apparently inhabit a lower activity area. It is hypothesized that the new species, which lacks eyes, is a permanent resident of <span class="hlt">vent</span> fields on the Mid-Atlantic Ridge, but is probably not restricted to that environment.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/10191348','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/10191348"><span id="translatedtitle">Transport characteristics across drum filter <span class="hlt">vents</span> and polymer bags</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Liekhus, K.J.</p> <p>1994-08-01</p> <p>The rate at which hydrogen (H {sub 2}) or a volatile organic compound (VOC) exits a layer of confinement in a <span class="hlt">vented</span> waste drum is proportional to the concentration difference across the layer. The proportionality constant is the gas transport characteristic. A series of transport experiments were conducted to determine H{sub 2} and VOC transport characteristics across different drum filter <span class="hlt">vents</span> and polymer bags. This report reviews the methods and results of past investigators in defining transport characteristics across filter <span class="hlt">vents</span> and polymer bags, describes the apparatus and procedures used in these experiments, compares the reported and estimated transport characteristics with earlier results, and discusses the impact of changing the transport characteristic values used in model calculations.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19930081137','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19930081137"><span id="translatedtitle">The Prevention of Ice Formation on Gasoline Tank <span class="hlt">Vents</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Theodorsen, Theodore; Clay, William C</p> <p>1931-01-01</p> <p>This investigation was conducted in the refrigerated wind tunnel at the Langley Memorial Aeronautical Laboratory, Langley Field, Va., to determine a suitable method for preventing the formation of ice on the <span class="hlt">vents</span> of airplane gasoline tanks. Tests were made on a variety of <span class="hlt">vent</span> forms arranged in a number of different orientations relative to the direction of the air stream. Both the size of the tube and its orientation were found to be of great importance. Small tubes, under equal circumstances, were found to freeze over far more rapidly than large ones. Tubes pointing downstream, or shielded in other ways, appear to be perfectly immune against this hazard. A tube 3/4 inch in diameter with the opening pointing downstream is finally recommended as being the safest choice of gas tank <span class="hlt">vent</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010EOSTr..91R.142S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010EOSTr..91R.142S"><span id="translatedtitle">In Brief: Volcanic <span class="hlt">vents</span> found in deep Caribbean waters</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Showstack, Randy</p> <p>2010-04-01</p> <p>Scientists surveying the Cayman Trough in the Caribbean Sea have discovered the world's deepest undersea volcanic <span class="hlt">vents</span>, or “black smokers,” the National Oceanography Center (NOC) in Southampton, UK, announced on 11 April. The <span class="hlt">vents</span> were found at a depth of 5000 meters, about 800 meters deeper than any previously discovered. Jon Copley, a marine biologist at the University of Southampton's School of Ocean and Earth Science, said, “Seeing the world's deepest black-smoker <span class="hlt">vents</span> looming out of the darkness was awe-inspiring.” Geochemist Doug Connelly of NOC, principal scientist of the expedition, noted, “We hope our discovery will yield new insights into biogeochemically important elements in one of the most extreme naturally occurring environments on our planet.” Researchers used an NOC-developed Autosub6000 robot submarine, which was remotely controlled from the Royal Research Ship James Cook. For more information, visit http://www.thesearethevoyages.net/.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014EGUGA..16.5642B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014EGUGA..16.5642B"><span id="translatedtitle"><span class="hlt">Vents</span> Pattern Analysis at Etna volcano (Sicily, Italy).</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Brancato, Alfonso; Tusa, Giuseppina; Coltelli, Mauro; Proietti, Cristina; Branca, Stefano</p> <p>2014-05-01</p> <p>Mount Etna is a composite stratovolcano located along the Ionian coast of eastern Sicily. It is characterized by basaltic eruptions, both effusive and explosive, occurred during a complex eruptive history over the last 500 ka. Flank eruptions occur at an interval of decades, mostly concentrated along the NE, S and W rift zones. A <span class="hlt">vent</span> clustering at various scales is a common feature in many volcanic settings. In order to identify the clusters within the studied area, a spatial point pattern analysis is undertaken using <span class="hlt">vent</span> positions, both known and reconstructed. It reveals both clustering and spatial regularity in the Etna region at different distances. The visual inspection of the <span class="hlt">vent</span> spatial distribution suggests a clustering on the rift zones of Etna volcano. To confirm this evidence, a coarse analysis is performed by the application of Ξ2- and t-test simple statistics. Then, a refined analysis is performed by using the Ripley K-function (Ripley, 1976), whose estimator K(d), knowing the area of the study region and the number of <span class="hlt">vents</span>, allow us to calculate the distance among two different location of events. The above estimator can be easier transformed by using the Besag L-function (Besag, 1977); the peaks of positive L(d)=[K(d)/π]1/2 -d values indicate clustering while troughs of negative values stand for regularity for their corresponding distances d (L(d)=0 indicates complete spatial randomness). Spatial pattern of flank <span class="hlt">vents</span> is investigated in order to model the spatial distribution of likely eruptive <span class="hlt">vents</span> for the next event, basically in terms of relative probabilities. For this, a Gaussian kernel technique is used, and the L(d) function is adopted to generate an optimal smoothing bandwidth based on the clustering behaviour of the Etna volcano. A total of 154 <span class="hlt">vents</span> (among which 36 are reconstructed), related to Etna flank activity of the last 4.0 ka, is used to model future <span class="hlt">vent</span> opening. The investigated region covers an area of 850 km2, divided</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20100031201','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20100031201"><span id="translatedtitle">Bus <span class="hlt">Vent</span> Design Evolution for the Solar Dynamics Observatory</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Woronowicz, Michael</p> <p>2010-01-01</p> <p>As a spacecraft undergoes ascent in a launch vehicle, its pressure environment transitions from one atmosphere to high vacuum in a matter of minutes. <span class="hlt">Venting</span> of internal cavities is necessary to prevent the buildup of pressure differentials across cavity walls. Opposing the need to <span class="hlt">vent</span> these volumes freely into space are thermal, optical, and electrostatic requirements for limiting or prohibiting the intrusion of unwanted energy into the same cavities. Bus <span class="hlt">vent</span> design evolution is discussed for the Solar Dynamics Observatory. Design changes were influenced by a number of factors and concerns, such as contamination control, electrostatic discharge, changes in bus material, and driving fairing ascent pressure for a launch vehicle that was just entering service as this satellite project had gotten underway.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012AGUFMOS24B..07T','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012AGUFMOS24B..07T"><span id="translatedtitle">Post-drilling hydrothermal <span class="hlt">vent</span> and associated biological activities seen through artificial hydrothermal <span class="hlt">vents</span> in the Iheya North field, Okinawa Trough</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Takai, K.; Kawagucci, S.; Miyazaki, J.; Watsuji, T.; Ishibashi, J.; Yamamoto, H.; Nozaki, T.; Kashiwabara, T.; Shibuya, T.</p> <p>2012-12-01</p> <p>In 2010, IODP Expedition 331 was conducted in the Iheya North Field, the Okinawa Trough and drilled several sites in hydrothermally active subseafloor. In addition, during the IODP Expedition 331, four new hydrothermal <span class="hlt">vents</span> were created. These post-drilling artificial hydrothermal <span class="hlt">vents</span> provide excellent opportunities to investigate the physical, chemical and microbiological characteristics of the previously unexplored subseafloor hydrothermal fluid reservoirs, and to monitor and estimate how the anthropogenic drilling behaviors affect the deep-sea hydrothermal <span class="hlt">vent</span> ecosystem. We were very much interested in the difference of hydrothermal fluid chemistry between the natural hydrothermal <span class="hlt">vents</span> and the artificial hydrothermal <span class="hlt">vents</span>. The IODP porewater chemistry of the cores pointed to the density-driven stratification of the phase-separated hydrothermal fluids and the natural <span class="hlt">vent</span> fluids were likely derived only from the shallower vapor-enriched phases. However, the artificial hydrothermal <span class="hlt">vents</span> had deeper fluid sources in the subseafloor hydrothermal fluid reservoirs composed of vapor-lost (Cl-enriched) phases. The fluids from the artificial hydrothermal <span class="hlt">vents</span> were sampled by ROV at 5, 12 and 18 months after the IODP expedition. The artificial hydrothermal <span class="hlt">vent</span> fluids were slightly enriched with Cl as compared to the natural hydrothermal <span class="hlt">vent</span> fluids. Thus, the artificial hydrothermal <span class="hlt">vents</span> successfully entrained the previously unexplored subseafloor hydrothermal fluids. The newly created hydrothermal <span class="hlt">vents</span> also hosted the very quickly grown, enormous chimney structures, of which mineral compositions were highly variable among the <span class="hlt">vents</span>. However, the quickly grown C0016B and C0016D <span class="hlt">vent</span> chimneys were found to be typical Kuroko ore even though the chimney growth rates in the artificial <span class="hlt">vents</span> were extremely faster than those in the natural <span class="hlt">vents</span>. In addition, the IODP drilling operation not only created new hydrothermal <span class="hlt">vents</span> by deep drilling but also induced the</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/8913148','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/8913148"><span id="translatedtitle">Effect of proximal and distal <span class="hlt">venting</span> during intramedullary nailing.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Martin, R; Leighton, R K; Petrie, D; Ikejiani, C; Smyth, B</p> <p>1996-11-01</p> <p>During intramedullary manipulation, 2 main phenomena occur. A dramatic rise in intramedullary pressure occurs followed by intravasation of damaged marrow tissue. There are concerns about the development of increased interosseous pressure during reaming and the potential for this to contribute to fat embolism syndrome. The intramedullary pressures generated with various intramedullary devices was determined and the effects of a fracture, with and without proximal and distal <span class="hlt">venting</span> on these pressures were studied. Pressures generated in 78 embalmed anatomic specimen femurs and tibias were studied, leaving all soft tissues intact. Pressures were recorded for awl, guide rod, reamer, and nail insertion. <span class="hlt">Venting</span> was done by creating a 4.5-mm hole in the cortex directly opposite the transducer. Proximal <span class="hlt">venting</span> reduced proximal pressures to 80 mm Hg in the tibia (90% reduction) and 460 mm Hg in the femur (70% reduction). Distal <span class="hlt">venting</span> reduced distal pressures to 65 mm and 30 mm in the tibias and femurs, respectively (90% reduction in pressures). Intramedullary pressures generated during nail or alignment rod insertion in anatomic specimen bone greatly exceeds the critical thresholds (150 mm Hg) thought to be responsible for fat emboli to the lung in the dogs. The introduction of a <span class="hlt">vent</span> may reduce the chance of fat embolism. Despite the high association of raised intramedullary pressures and fat emboli in animal studies, there is no known critical threshold for humans. Therefore, although <span class="hlt">venting</span> seems effective in reducing the intramedullary pressure in anatomic specimen bones, its efficacy in the patient with trauma remains to be determined. PMID:8913148</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2009EGUGA..11.7272K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2009EGUGA..11.7272K"><span id="translatedtitle">Hydrothermal Fluxes at the Turtle Pits <span class="hlt">Vent</span> Site, southern MAR</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Köhler, J.; Walter, M.; Mertens, C.; Sültenfuß, J.; Rhein, M.</p> <p>2009-04-01</p> <p>The Turtle Pits <span class="hlt">vent</span> fields are located in a north-south orientated rift valley at the Mid-Atlantic Ridge (MAR) near 5oS. The site consists of three known hydrothermal fields: Turtle Pits, Comfortless Cove, and Red Lion. Data collected during a Meteor cruise in May 2006 and a L' Atalante cruise in January 2008 are used to calculate the total emission of volume, heat, and helium of the site. The data sets consist of vertical profiles and towed transsects of temperature, salinity, and turbidity, as well as direct velocity measurements with a lowered acoustic Doppler current profiler (LADCP) and water samples for Helium isotope analysis. <span class="hlt">Vent</span> fluid samples for noble gas analysis where taken with an ROV. The particle plume is confined to the rift valley since the depth of the valley exceeds the rise height of the plume. Therefore the fluxes of heat and volume can be estimated from the helium fluxes at the <span class="hlt">vent</span> sites in comparison with the horizontal helium transport in the valley. The comparison of the 3He concentration measured south of the hydrothermal <span class="hlt">vents</span> with the 3He signal north of the hydrothermal <span class="hlt">vents</span> suggests a rather strong northward flow. This is confirmed by the tide corrected velocities observed with the LADCP during the Meteor cruise. The northward volume transport has been calculated using the local bathymetry and tide corrected velocities from the Meteor cruise. In combination with the 3He concentrations and an average 3He end member concentration a flux of 900 l/s is estimated, which corresponds to a heat flux of 450 MW. The rise height of the particle plume estimated from the turbidity data combined with the known background stratification yields an estimate of the total flux of the hydrothermal <span class="hlt">vents</span> which is one order of magnitude lower.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/251010','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/251010"><span id="translatedtitle">Level 2 PSA insights relative to filtered <span class="hlt">vent</span> system</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Deremer, R.K.; Fleming, K.N.; Landolt, J.</p> <p>1996-07-01</p> <p>A full-scope Level 2 probabilistic safety analysis (PSA) of the Goesgen Nuclear Power Plant was completed early in 1994. During the PSA, a containment filtered <span class="hlt">vent</span> system was installed at the plant to meet requirements of the Swiss safety authorities. The purpose of the <span class="hlt">vent</span> system is to provide a mechanism to depressurize the containment atmosphere in a controlled manner during the late phase of a severe accident in order to preclude gradual over pressurization of the containment and filter any release of radioactive materials to the environment. To ensure a high degree of reliability, it was required to include a design feature to open the <span class="hlt">vent</span> passively via the use of a rupture disc whose opening is highly reliable and independent of operator actions. The PSA addressed two issues associated with the <span class="hlt">vent</span> system: (1) What is the optimum pressure to select for the rupture disc setpoint? and (2) What is the best strategy for the use of the rupture disc isolation valves (i.e., should they be left open normally to ensure the opening of the <span class="hlt">vent</span> at the rupture disc setpoint or should they be left closed and opened by the operator only during a severe accident)? Based on the results generated by the PSA, which indicated that the downside risk of inadvertent opening in the early phase of an accident was greater than the upside benefit of a passively actuated <span class="hlt">vent</span> in the late phase of an accident, it was concluded that it is prudent to have the rupture disc normally isolated from the containment.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2006cosp...36..334J','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2006cosp...36..334J"><span id="translatedtitle">NASA/JPL hydrothermal <span class="hlt">vent</span> bio-sampler</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Jonsson, J.; Behar, A.; Bruckner, J.; Matthews, J.</p> <p></p> <p>pagestyle empty begin document On the bottom of the oceans with volcanic activity present hydrothermal <span class="hlt">vents</span> can be found which spew out mineral rich superheated water from the porous seafloor crust Some of these <span class="hlt">vents</span> are situated several thousands of meters below the surface where the sunlight never reaches Yet life thrives here on the minerals and chemical compounds that the <span class="hlt">vent</span> water brings up with it This chemosynthetic microbial community forms the basis of some of the most interesting ecosystems on our planet and could possibly also be found on other water rich planets and moons in the solar system Perhaps under the icy surface of the moon Europa there exist hydrothermal <span class="hlt">vents</span> with such biota thriving independently of the solar energy The Hydrothermal <span class="hlt">Vent</span> Bio-sampler HVB is a system which will be used to collect pristine samples of the water emanating from hydrothermal <span class="hlt">vents</span> An array of temperature and flow sensors will monitor the sampling conditions This will allow for the samples to be collected from defined locations within the plume and the diversity and distribution of the chemosynthetic communities that might live there can be accurately described The samples will have to be taken without any contamination from the surrounding water thus the pristine requirement Monitoring the flow will assure that enough water has been sampled to account for the low biomass of these environments The system will be using a series of filters down to 0 2 mu m in pore size and the samples can be directly collected from the system for both culture-</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li class="active"><span>24</span></li> <li><a href="#" onclick='return showDiv("page_25");'>25</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_24 --> <div id="page_25" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li><a href="#" onclick='return showDiv("page_24");'>24</a></li> <li class="active"><span>25</span></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="481"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2001E%26PSL.193..395K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2001E%26PSL.193..395K"><span id="translatedtitle">Discovery of new hydrothermal <span class="hlt">vent</span> sites in Bransfield Strait, Antarctica</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Klinkhammer, G. P.; Chin, C. S.; Keller, R. A.; Dählmann, A.; Sahling, H.; Sarthou, G.; Petersen, S.; Smith, F.; Wilson, C.</p> <p>2001-12-01</p> <p>We carried out a search for hydrothermal <span class="hlt">vents</span> in the Central Basin of Bransfield Strait, Antarctica. The ZAPS (zero angle photon spectrometer) chemical sensor and instrument package (Oregon State University), OFOS (ocean-floor observation system) camera sled and TVG (TV-grab) (GEOMAR) were used to explore the water column and underlying seafloor. These operations were supplemented with a series of dredges. Hydrothermal plumes over Hook Ridge at the eastern end of the basin are confined to the E ridge crest and SE flank. The plumes are complex and sometimes contain two turbidity maxima one widespread feature centered at 1150 m and a smaller, more localized but broad maximum at 600-800 m. We traced the source of the shallower plume to a sunken crater near the ridge crest using sensors on the ZAPS instrument package. Subsequently two TV-grabs from the crater brought back hot, soupy sediment (42-49°C) overlain by hard, siliceous crusts and underlain by a thick layer of volcanic ash. We also recovered chimney fragments whose texture and mineralogy indicate <span class="hlt">venting</span> temperatures in excess of 250°C. Native sulfur and Fe-sulfides occur in fractures and porous layers in sediment from throughout the area. Pore water data from the crater site are consistent with <span class="hlt">venting</span> into a thin sediment layer and indicate phase separation of fluids beneath Hook Ridge. The source of the deeper plumes at Hook Ridge has yet to be located. We also explored a series of three parallel volcanic ridges west of Hook Ridge called Three Sisters. We detected water column anomalies indicative of <span class="hlt">venting</span> with the ZAPS package and recovered hydrothermal barites and sulfides from Middle Sister. We spent considerable time photographing Middle Sister and Hook Ridge but did not identify classic <span class="hlt">vent</span> fauna at either location. We either missed small areas with our photography or typical MOR <span class="hlt">vent</span> fauna are absent at these sites.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19990106579&hterms=gravity+definition&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3Dgravity%2Bdefinition','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19990106579&hterms=gravity+definition&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3Dgravity%2Bdefinition"><span id="translatedtitle">Zero Gravity Cryogenic <span class="hlt">Vent</span> System Concepts for Upper Stages</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Flachbart, Robin H.; Holt, James B.; Hastings, Leon J.</p> <p>1999-01-01</p> <p>The capability to <span class="hlt">vent</span> in zero gravity without resettling is a technology need that involves practically all uses of sub-critical cryogenics in space. <span class="hlt">Venting</span> without resettling would extend cryogenic orbital transfer vehicle capabilities. However, the lack of definition regarding liquid/ullage orientation coupled with the somewhat random nature of the thermal stratification and resulting pressure rise rates, lead to significant technical challenges. Typically a zero gravity <span class="hlt">vent</span> concept, termed a thermodynamic <span class="hlt">vent</span> system (TVS), consists of a tank mixer to destratify the propellant, combined with a Joule-Thomson (J-T) valve to extract thermal energy from the propellant. Marshall Space Flight Center's (MSFC's) Multipurpose Hydrogen Test Bed (MHTB) was used to test both spray bar and axial jet TVS concepts. The axial jet system consists of a recirculation pump heat exchanger unit. The spray bar system consists of a recirculation pump, a parallel flow concentric tube, heat exchanger, and a spray bar positioned close to the longitudinal axis of the tank. The operation of both concepts is similar. In the mixing mode, the recirculation pump withdraws liquid from the tank and sprays it into the tank liquid, ullage, and exposed tank surfaces. When energy is required. a small portion of the recirculated liquid is passed sequentially through the J-T expansion valve, the heat exchanger, and is <span class="hlt">vented</span> overboard. The <span class="hlt">vented</span> vapor cools the circulated bulk fluid, thereby removing thermal energy and reducing tank pressure. The pump operates alone, cycling on and off, to destratify the tank liquid and ullage until the liquid vapor pressure reaches the lower set point. At that point. the J-T valve begins to cycle on and off with the pump. Thus, for short duration missions, only the mixer may operate, thus minimizing or even eliminating, boil-off losses.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19880016019','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19880016019"><span id="translatedtitle">Contamination of the space station environment by <span class="hlt">vented</span> chemicals</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Bernhardt, Paul A.</p> <p>1988-01-01</p> <p>Gaseous materials <span class="hlt">vented</span> from materials and life science experiments on the Space Station may have noticeable effects on the optical or plasma environment. The magnitude of the effects depends on: (1) rarefied gas dynamics; (2) photochemical reactions; and (3) airglow excitation mechanisms. In general, the effects from atomic species can be mitigated, but the disturbances resulting from <span class="hlt">venting</span> of molecules like SF6, CO2 and C2H2 can be significant. The interaction of molecules with ambient plasma at orbital velocities should be studied with laboratory or space experiments.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://pubs.er.usgs.gov/publication/70170844','USGSPUBS'); return false;" href="http://pubs.er.usgs.gov/publication/70170844"><span id="translatedtitle">Hydrothermal <span class="hlt">vents</span> and methane seeps: Rethinking the sphere of influence</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Levin, Lisa A.; Baco, Amy; Bowden, David; Colaco, Ana; Cordes, Erik E.; Cunha, Marina; Demopoulos, Amanda; Gobin, Judith; Grupe, Ben; Le, Jennifer; Metaxas, Anna; Netburn, Amanda; Rouse, Greg; Thurber, Andrew; Tunnicliffe, Verena; Van Dover, Cindy L.; Vanreusel, Ann; Watling, Les</p> <p>2016-01-01</p> <p>Although initially viewed as oases within a barren deep ocean, hydrothermal <span class="hlt">vent</span> and methane seep communities are now recognized to interact with surrounding ecosystems on the sea floor and in the water column, and to affect global geochemical cycles. The importance of understanding these interactions is growing as the potential rises for disturbance from oil and gas extraction, seabed mining and bottom trawling. Here we synthesize current knowledge of the nature, extent and time and space scales of <span class="hlt">vent</span> and seep interactions with background systems. We document an expanded footprint beyond the site of local <span class="hlt">venting</span> or seepage with respect to elemental cycling and energy flux, habitat use, trophic interactions, and connectivity. Heat and energy are released, global biogeochemical and elemental cycles are modified, and particulates are transported widely in plumes. Hard and biotic substrates produced at <span class="hlt">vents</span> and seeps are used by “benthic background” fauna for attachment substrata, shelter, and access to food via grazing or through position in the current, while particulates and fluid fluxes modify planktonic microbial communities. Chemosynthetic production provides nutrition to a host of benthic and planktonic heterotrophic background species through multiple horizontal and vertical transfer pathways assisted by flow, gamete release, animal movements, and succession, but these pathways remain poorly known. Shared species, genera and families indicate that ecological and evolutionary connectivity exists among <span class="hlt">vents</span>, seeps, organic falls and background communities in the deep sea; the genetic linkages with inactive <span class="hlt">vents</span> and seeps and background assemblages however, are practically unstudied. The waning of <span class="hlt">venting</span> or seepage activity generates major transitions in space and time that create links to surrounding ecosystems, often with identifiable ecotones or successional stages. The nature of all these interactions is dependent on water depth, as well as</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20160000764','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20160000764"><span id="translatedtitle">Pressure <span class="hlt">Venting</span> Tests of Phenolic Impregnated Carbon Ablator (PICA)</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Blosser, Max L.; Knutson, Jeffrey R.</p> <p>2015-01-01</p> <p>A series of tests was devised to investigate the pressure <span class="hlt">venting</span> behavior of one of the candidate ablators for the Orion capsule heat shield. Three different specimens of phenolic impregnated carbon ablator (PICA) were instrumented with internal pressure taps and subjected to rapid pressure changes from near vacuum to one atmosphere and simulated Orion ascent pressure histories. The specimens <span class="hlt">vented</span> rapidly to ambient pressure and sustained no detectable damage during testing. Peak pressure differences through the thickness of a 3-inch-thick specimen were less than 1 psi during a simulated ascent pressure history.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19900055090&hterms=back+fill&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3Dback%2Bfill','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19900055090&hterms=back+fill&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3Dback%2Bfill"><span id="translatedtitle">Analytical modelling of no-<span class="hlt">vent</span> fill process</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Vaughan, David A.; Schmidt, George R.</p> <p>1990-01-01</p> <p>An analytical model called FILL is presented which represents the first step in attaining the capability for no-<span class="hlt">vent</span> fill of cryogens in space. The model's analytical structure is described, including the equations used to calculate transient thermodynamic behavior in different regions of the tank. The code predictions are compared with data from recent no-<span class="hlt">vent</span> fill ground tests using Freon-114. The results are used to validate the FILL model to evaluate the viability of universal submerged jet theory in predicting system-level condensation effects.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016RMRE...49..763C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016RMRE...49..763C"><span id="translatedtitle">Mechanical Behavior of Brittle Rock-Like Specimens with Pre-existing <span class="hlt">Fissures</span> Under Uniaxial Loading: Experimental Studies and Particle Mechanics Approach</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Cao, Ri-hong; Cao, Ping; Lin, Hang; Pu, Cheng-zhi; Ou, Ke</p> <p>2016-03-01</p> <p>Joints and <span class="hlt">fissures</span> with similar orientation or characteristics are common in natural rocks; the inclination and density of the <span class="hlt">fissures</span> affect the mechanical properties and failure mechanism of the rock mass. However, the strength, crack coalescence pattern, and failure mode of rock specimens containing multi-<span class="hlt">fissures</span> have not been studied comprehensively. In this paper, combining similar material testing and discrete element numerical method (PFC2D), the peak strength and failure characteristics of rock-like materials with multi-<span class="hlt">fissures</span> are explored. Rock-like specimens were made of cement and sand and pre-existing <span class="hlt">fissures</span> created by inserting steel shims into cement mortar paste and removing them during curing. The peak strength of multi-<span class="hlt">fissure</span> specimens depends on the <span class="hlt">fissure</span> angle α (which is measured counterclockwise from horizontal) and <span class="hlt">fissure</span> number ( N f). Under uniaxial compressional loading, the peak strength increased with increasing α. The material strength was lowest for α = 25°, and highest for α = 90°. The influence of N f on the peak strength depended on α. For α = 25° and 45°, N f had a strong effect on the peak strength, while for higher α values, especially for the 90° sample, there were no obvious changes in peak strength with different N f. Under uniaxial compression, the coalescence modes between the <span class="hlt">fissures</span> can be classified into three categories: S-mode, T-mode, and M-mode. Moreover, the failure mode can be classified into four categories: mixed failure, shear failure, stepped path failure, and intact failure. The failure mode of the specimen depends on α and N f. The peak strength and failure modes in the numerically simulated and experimental results are in good agreement.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2012AGUFM.V53H..01D&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2012AGUFM.V53H..01D&link_type=ABSTRACT"><span id="translatedtitle">Controls on the evolving grain size distribution of ash in explosive eruptions and feedback in <span class="hlt">vent</span> proximal dynamics</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Dufek, J.</p> <p>2012-12-01</p> <p>The dispersal range of eruptive products and <span class="hlt">types</span> of hazards they present is determined in large part by the volume and size fraction of particles that exit the volcanic <span class="hlt">vent</span> and how this grain size distribution changes during transport. This talk will examine the physical processes that modify the grain size distribution of particles across a spectrum of energies due to eruptive processes from the conduit, multiphase interaction in the plume, and due to microscale aggregation of ash. The size distribution of volcanic particles has widely been interpreted to be associated with the initial fragmentation process, where particle size has been attributed to fragmentation style and efficiency. Here we evaluate the likelihood that pumice particles survive intact the high-energy environment of the volcanic conduit from the point of initial fragmentation to ejection into the atmosphere. We show that the probability of particles surviving intact is strongly controlled by the particles initial size and the depth of the fragmentation level, with large particles and deep fragmentation producing the most disruption events. The consequence of numerous high-energy collisions results in a more homogeneous, fine-grained mixture of particles leaving the volcanic <span class="hlt">vent</span> for volcanoes with deep fragmentation levels. These fine particles are well coupled to the magmatic gases exiting the <span class="hlt">vent</span>, can reduce their sound speed and influence the ability of the mixture to entrain ambient air, thus influencing eruptive style. After exiting the volcanic <span class="hlt">vent</span>, ash is subject to a range of microphysical processes such adsorption of water and aggregation. After briefly reviewing recent experimental advances in ash microphysical phenomena we will illustrate how these processes can influence near <span class="hlt">vent</span> dynamics by incorporating these microphysical experimental results into a high resolution Eulerian-Eulerian-Lagrangian (EEL) model. We will particularly focus on the dual roles of aggregation and</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2003AGUFM.B12A0760C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2003AGUFM.B12A0760C"><span id="translatedtitle">The Majority of Free-Living Autotrophic Bacteria use the Reductive TCA Cycle for Carbon Fixation at Deep-Sea Hydrothermal <span class="hlt">Vents</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Campbell, B. J.; Cary, C.</p> <p>2003-12-01</p> <p>Deep-sea hydrothermal <span class="hlt">vents</span> support large micro and macroscopic communities, without the input of photosynthesis. Autotrophic production at these <span class="hlt">vents</span> is based on hydrothermal <span class="hlt">vent</span> fluid chemistry. Primary production has been thought to occur mainly via hydrogen sulfide oxidation through the Calvin-Benson pathway, as measured by the presence of Rubisco in endosymbionts of several invertebrate hosts. Recently, we characterized two fosmids from a large insert library of the epsilon Proteobacterial episymbionts of Alvinella pompejana. Both contained sequences encoding ATP citrate lyase, a key enzyme in the reverse TCA cycle, an alternate carbon dioxide fixation pathway. Previous investigators have demonstrated the dominance of the epsilon subdivision in the free-living bacterial communities at hydrothermal <span class="hlt">vents</span>. Based on these results, our working hypothesis is: The rTCA cycle is the dominant pathway for carbon fixation in the free-living bacterial communities at hydrothermal <span class="hlt">vents</span>. A selection of free-living bacterial communities from various geographic locations (9N, East Pacific Rise and Guaymas Basin) were screened for the presence, diversity and expression (via RT-PCR) of Rubisco (forms I and II) and ATP citrate lyase. Our results indicate that the ATP citrate lyase gene is diverse and is consistently expressed in several <span class="hlt">types</span> of <span class="hlt">vent</span> communities. The two forms of Rubisco are not consistently present or expressed in the same environments. These results indicate that chemoautotrophic production in the free-living bacterial communities at deep-sea hydrothermal <span class="hlt">vents</span> is dominated by bacteria that utilize the rTCA cycle, and parallels the phylogenetic dominance of members of the epsilon subdivision of Proteobacteria.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/6896563','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/6896563"><span id="translatedtitle">An overview of BWR Mark-I containment <span class="hlt">venting</span> risk implications</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Wagner, K.C.; Dallman, R.J.; Galyean, W.J.</p> <p>1988-11-01</p> <p><span class="hlt">Venting</span> of boiling water reactors with Mark-I containments has been suggested as a way to prevent catastrophic failure and/or mitigate the consequences resulting from a severe accident. Based on phenomenological, human factors, and risk considerations, the potential benefits and downsides of <span class="hlt">venting</span> Mark-I containments were analyzed. Several generic <span class="hlt">venting</span> systems and two proposed utility systems were reviewed. Based on generic considerations, the offsite consequences during risk dominant accidents were qualitatively assessed for four different <span class="hlt">vent</span> systems. A quantitative risk study of an early <span class="hlt">venting</span> strategy was performed, based on the existing Peach Bottom hardware and the draft NUREG-1150 results for Peach Bottom. Appendices are also included which contain reviews of the Pilgrim and Vermont Yankee <span class="hlt">venting</span> submitals, a response to the seven questions from the NRC about the Pilgrim <span class="hlt">venting</span> strategy, and a review of the <span class="hlt">venting</span> strategy directed by Revision 4 of the Boiling Water Reactor Emergency Procedures Guidelines. 16 refs., 7 figs., 7 tabs.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010EGUGA..1211022R','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010EGUGA..1211022R"><span id="translatedtitle">Analysis of displacements and <span class="hlt">fissure</span> structures on a slow-moving landslide through very high-resolution orthophoto mosaicing</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Rothmund, Sabrina; Joswig, Manfred; Niethammer, Uwe; Malet, Jean-Philippe</p> <p>2010-05-01</p> <p>Very high-resolution multi-temporal images with a ground resolution of a few centimeters allowed to detect and analyze displacements and <span class="hlt">fissure</span> patterns of the Super-Sauze landslide (Southern French Alps). Images taken by an unmanned aerial vehicle (UAV) during a flight campaign in October 2008 have been used to produce a very high-resolution orthophoto-mosaic of the landslide. In this study, a set of 59 of a total of 1486 images was selected and photogrammetrically processed using different non-parametric rectification approaches (projective transformation, piecewise affine transformation and polynomial transformations of the second and third order). The generated orthophoto-mosaic covers the entire landslide area of 0.09 km² with a ground resolution of 3 to 8 cm. The comparison of this UAV-based orthophoto-mosaic with an orthophotograph from May 2007 (ground resolution of 20 cm) allowed the characterization of the horizontal displacements of the landslide. Displacement vectors were estimated by visually inspecting the images to identify distinct features (rocks, boulders and vegetation patches) in the two orthophotographs. This approach was chosen because of the high dynamics of the landslide and the disadvantageous long period between the repeated image acquisitions. Displacements between 7.1 and 55.4 m in varying directions have been detected and areas of different dynamics could be distinguished for the period between May 2007 and October 2008. Various structures, in particular <span class="hlt">fissures</span> of different distributions and orientations, could be resolved in the UAV-based orthophoto-mosaic. The similarity of the observed <span class="hlt">fissures</span> with glacial crevasses is striking and suggests a similar genesis. The identified longitudinal, transverse and cross-shaped <span class="hlt">fissures</span> are linked to abrupt changes of in-situ crest orientation in the shallow subsurface. The observed shear <span class="hlt">fissures</span> occur at the lateral boundary of emerging in-situ crests. The <span class="hlt">fissure</span> genesis could be traced</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016EGUGA..1812395T','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016EGUGA..1812395T"><span id="translatedtitle">Interaction between central volcanoes and <span class="hlt">fissure</span> swarms along divergent plate boundaries: an example from Askja Volcano, Northern Iceland.</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Trippanera, Daniele; Ruch, Joel; Acocella, Valerio; Urbani, Stefano; Thordarson, Thor</p> <p>2016-04-01</p> <p>Central volcanoes located along divergent plate boundaries are typically part of a larger volcanic system that consists of a central edifice and a <span class="hlt">fissure</span> swarm through which magma propagates and spreads plates apart. Regional normal faults and graben structures develop within the volcanic system, also dissecting portions of the central volcano with ring-faults faults and eruptive <span class="hlt">fissures</span> related to the caldera structure. Both the <span class="hlt">fissure</span> swarm and the caldera structure influence the pathway of the ascending magma, however, the influences of the structures on magma propagation and vice versa are not well defined and understood. Here we aim to understand the relationship between the activity of the central volcano structures (e.g. caldera ring faults, radial dykes and cone sheets) and those of the <span class="hlt">fissure</span> swarm (e.g. regional normal faults, regional dikes). We focus on Askja volcano, located in the Northern Volcanic Zone of Iceland. It is comprised of three nested calderas, largely filled in with subaerial basaltic lava flows and surrounded by a massive hyaloclastite mountain on the Eastern side. Formation of the youngest, the Öskjuvatn caldera, was initiated during the 1874-1876 rifting episode on the Askja system. This major event was followed by several localized radial and circumferential magmatic intrusions taking place along the new-formed caldera ring fault, as well as intruding in the <span class="hlt">fissure</span> swarm related to the regional tectonics. In order to characterize the influence of the caldera structure on the regional tectonics, we analysed the structural framework of the caldera and direct surroundings using remote sensing (optical imagery and high resolution DEM from TanDEM-X data). Then we made detailed field measurements (500 data) by analysing azimuth, dip, and opening of eruptive <span class="hlt">fissures</span>, dikes, faults and extension fractures. Both remote sensing and field measurements have been then integrated producing a detailed structural map of Askja. Our results show</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1998BVol...60..195S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1998BVol...60..195S"><span id="translatedtitle">Formation of clastogenic lava flows during <span class="hlt">fissure</span> eruption and scoria cone collapse: the 1986 eruption of Izu-Oshima Volcano, eastern Japan</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Sumner, Janet M.</p> <p></p> <p>The 1986 eruption of B <span class="hlt">fissure</span> at Izu-Oshima Volcano, Japan, produced, among other products, one andesite and two basaltic andesite lava flows. Locally the three flows resemble <span class="hlt">vent</span>-effused holocrystalline blocky or aa lava; however, remnant clast outlines can be identified at most localities, indicating that the flows were spatter fed or clastogenic. The basaltic andesite flows are interpreted to have formed by two main processes: (a) reconstitution of fountain-generated spatter around <span class="hlt">vent</span> areas by syn-depositional agglutination and coalescence, followed by extensional non-particulate flow, and (b) syn-eruptive collapse of a rapidly built spatter and scoria cone by rotational slip and extensional sliding. These processes produced two morphologically distinct lobes in both flows by: (a) earlier non-particulate flow of agglutinate and coalesced spatter, which formed a thin lobe of rubbly aa lava (ca. 5 m thick) with characteristic open extension cracks revealing a homogeneous, holocrystalline interior, and (b) later scoria-cone collapse, which created a larger lobe of irregular thickness (<20 m) made of large detached blocks of scoria cone interpreted to have been rafted along on a flow of coalesced spatter. The source regions of these lava flows are characterized by horseshoe-shaped scarps (<30 m high), with meso-blocks (ca. 30 m in diameter) of bedded scoria at the base. One lava flow has a secondary lateral collapse zone with lower (ca. 7 m) scarps. Backward-tilted meso-blocks are interpreted to be the product of rotational slip, and forward-tilted blocks the result of simple toppling. Squeeze-ups of coalesced spatter along the leading edge of the meso-blocks indicate that coalescence occurred in the basal part of the scoria cone. This low-viscosity, coalesced spatter acted as a lubricating layer along which basal failure of the scoria cone occurred. Rotational sliding gave way to extensional translational sliding as the slide mass spread out onto the present</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2008AGUFM.B53D..08O','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2008AGUFM.B53D..08O"><span id="translatedtitle">Isolation and Stability of Distinct Subsurface Microbial Communities Associated with Two Hydrothermal <span class="hlt">Vent</span> Systems</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Opatkiewicz, A. D.; Butterfield, D. A.; Baross, J. A.</p> <p>2008-12-01</p> <p>Subseafloor microbial communities may be important in global primary production and biogeochemical cycling. However, too little is known about the physiological and phylogenetic diversity and activity of these communities to assess this potential, and understanding the temporal and spatial variability in microbial community structure is critical. The microbial community structure of five geographically distinct hydrothermal <span class="hlt">vents</span> located within the Axial Seamount caldera, and four geographically distinct <span class="hlt">vents</span> within the Main Endeavour Field, Juan de Fuca Ridge, were examined over six years. Terminal restriction fragment length polymorphism (tRFLP) and 16S rRNA gene sequence analyses were used to determine the bacterial and archaeal diversity, and the statistical software Primer was used to compare <span class="hlt">vent</span> microbiology, temperature and fluid chemistry. Statistical analysis of <span class="hlt">vent</span> fluid temperature and chemical composition shows that there are significant differences between <span class="hlt">vents</span> in any year, and persistent differences in composition between one of the Axial <span class="hlt">vents</span> compared to the rest of the <span class="hlt">vents</span>. For the majority of <span class="hlt">vents</span>, however, the fluid composition changed over time such that separate <span class="hlt">vents</span> do not maintain a statistically distinct composition. In contrast, the subseafloor microbial communities associated with individual <span class="hlt">vents</span> also changed from year to year but each location maintained a distinct community structure (based on tRFLP and 16S rRNA gene sequence analyses) that was significantly different and greater than 60-percent dissimilar from all other <span class="hlt">vents</span> included in this study. At Axial, epsilon-proteobacterial microdiversity is shown to be important in distinguishing <span class="hlt">vent</span> communities. The deeper, high-temperature archaeal communities have more overlap between sites. We propose that persistent <span class="hlt">venting</span> at many diffuse sites over time creates the potential to isolate and stabilize diverse microbial community structures between <span class="hlt">vents</span>. Variation in dilution</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3565555','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3565555"><span id="translatedtitle">Influence of Laser Irradiation on Pits and <span class="hlt">Fissures</span>: An In Situ Study</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Correa–Afonso, Alessandra M; Pécora, Jesus D</p> <p>2013-01-01</p> <p>Abstract Objective: The aim of this in situ study was to analyze the influence of the Er:YAG, Nd:YAG, and CO2 lasers on the enamel acid resistance of pits and <span class="hlt">fissures</span>. Background data: The laser tissue interaction has been studied as a method of preventing occlusal caries. Methods: Thirteen volunteers wore palatal acrylic appliances containing human occlusal enamel blocks that were divided into four groups (G1, control; G2, Er:YAG; G3, Nd:YAG; G4, CO2). Each palatal acrylic appliance was used in the four studied groups and was used for 14 consecutive days. A sucrose solution was applied to the specimens six times per day. The specimens were then sectioned in half, and a microhardness test was applied. The other halves were analyzed using polarized light microscopy to measure the caries-like lesion areas, and a morphological analysis was conducted using a scanning electron microscope (SEM). Results: For the statistical analysis of the data obtained from the microhardness test (Knoop hardness number. [KHN]) (α=5%), Fisher's exact test was performed, and the group means were as follows: G1, 247±71; G2, 258±70; G3, 272±73; and G4, 298±56. The results demonstrated that the control group was significantly different from G3 and G4, which presented higher microhardness values. The Wilcoxon signed-rank test was used to analyze the data obtained from the caries-lesion area measurements (mm2) (α=5%) (G1, 0.01±1.08; G2, 0.13±0.18; G3, 0.05±0.17; and G4, 0.09±0.22). The results no showed significant differences among the groups in this analysis. Conclusions: Based on the results from the present study, it may be concluded that the CO2 and Nd:YAG lasers increased the enamel acid resistance in pits and <span class="hlt">fissures</span>. PMID:23336742</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/11204060','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/11204060"><span id="translatedtitle">Argon laser curing of fluoride-releasing pit and <span class="hlt">fissure</span> sealant: in vitro caries development.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Westerman, G; Hicks, J; Flaitz, C</p> <p>2000-01-01</p> <p>The purpose of this study was to compare the effect of argon laser polymerization of a visible-light-cured, fluoride-releasing pit and <span class="hlt">fissure</span> sealant on caries development in vitro. A total of twelve caries-free premolar and molar teeth was selected, and underwent a fluoride-free prophylaxis and soft tissue debridement. Cavity preparations were placed in buccal and lingual surfaces. Lingual cavity preparations were filled with the fluoride-releasing sealant (UltraSealXTplus, Ultradent) and visible light cured per the manufacturer's recommendation. Buccal preparations were filled with the fluoride-releasing sealant and argon laser cured (231 mW, 12 J/cm2 for 10 seconds). Following sealant placement, the teeth were sectioned into buccal and lingual halves. An acid-resistant varnish was placed leaving a 1 mm rim of exposed surface enamel adjacent to the sealant. The specimens were then thermocycled in synthetic saliva (500 cycles, 5 to 50 degrees C). In vitro caries lesions were formed (2.2 mM Ca, 2.2 mM PO4, 50 mM acetic acid, 5 ppm fluoride, pH 3.95). Longitudinal sections (five sections per tooth half) were obtained and evaluated by polarized light microscopy for mean outer surface lesion depths and frequency of wall lesions. Mean primary surface (outer) lesion depth was significantly decreased (ANOVA, DMR, P < .05) for the fluoride-releasing sealant with argon laser polymerization (152 +/- 16 um) when compared with visible light curing (211 +/- 23 um). Likewise, wall lesion frequency was substantially reduced for the argon laser polymerized sealants (17 percent) when compared with that for the visible light polymerized sealants (24 percent, ANOVA, DMR, P < .05). Argon laser polymerization of a fluoride-releasing pit and <span class="hlt">fissure</span> sealant improved caries resistance markedly in the surface enamel adjacent to the sealant material. Argon laser curing enhanced the caries protective ability of the sealant along the enamel-resin cavosurface, as noted by a decrease in wall</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.gpo.gov/fdsys/pkg/CFR-2012-title46-vol7/pdf/CFR-2012-title46-vol7-sec182-450.pdf','CFR2012'); return false;" href="https://www.gpo.gov/fdsys/pkg/CFR-2012-title46-vol7/pdf/CFR-2012-title46-vol7-sec182-450.pdf"><span id="translatedtitle">46 CFR 182.450 - <span class="hlt">Vent</span> pipes for fuel tanks.</span></a></p> <p><a target="_blank" href="http://www.gpo.gov/fdsys/browse/collectionCfr.action?selectedYearFrom=2012&page.go=Go">Code of Federal Regulations, 2012 CFR</a></p> <p></p> <p>2012-10-01</p> <p>... by reference; see 46 CFR 175.600), or 33 CFR 183, subpart J, or with diesel fuel tank <span class="hlt">vents</span> built in accordance with ABYC H-33 (incorporated by reference; see 46 CFR 175.600), will be considered as meeting the... screens or arrester elements. (f) A vessel of not more than 19.8 meters (65 feet) in length, carrying...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.gpo.gov/fdsys/pkg/CFR-2014-title46-vol4/pdf/CFR-2014-title46-vol4-sec119-450.pdf','CFR2014'); return false;" href="https://www.gpo.gov/fdsys/pkg/CFR-2014-title46-vol4/pdf/CFR-2014-title46-vol4-sec119-450.pdf"><span id="translatedtitle">46 CFR 119.450 - <span class="hlt">Vent</span> pipes for fuel tanks.</span></a></p> <p><a target="_blank" href="http://www.gpo.gov/fdsys/browse/collectionCfr.action?selectedYearFrom=2014&page.go=Go">Code of Federal Regulations, 2014 CFR</a></p> <p></p> <p>2014-10-01</p> <p>... 46 Shipping 4 2014-10-01 2014-10-01 false <span class="hlt">Vent</span> pipes for fuel tanks. 119.450 Section 119.450 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) SMALL PASSENGER VESSELS CARRYING MORE THAN 150 PASSENGERS OR WITH OVERNIGHT ACCOMMODATIONS FOR MORE THAN 49 PASSENGERS MACHINERY INSTALLATION Specific Machinery Requirements § 119.450...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.gpo.gov/fdsys/pkg/CFR-2013-title46-vol4/pdf/CFR-2013-title46-vol4-sec119-450.pdf','CFR2013'); return false;" href="https://www.gpo.gov/fdsys/pkg/CFR-2013-title46-vol4/pdf/CFR-2013-title46-vol4-sec119-450.pdf"><span id="translatedtitle">46 CFR 119.450 - <span class="hlt">Vent</span> pipes for fuel tanks.</span></a></p> <p><a target="_blank" href="http://www.gpo.gov/fdsys/browse/collectionCfr.action?selectedYearFrom=2013&page.go=Go">Code of Federal Regulations, 2013 CFR</a></p> <p></p> <p>2013-10-01</p> <p>... 46 Shipping 4 2013-10-01 2013-10-01 false <span class="hlt">Vent</span> pipes for fuel tanks. 119.450 Section 119.450 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) SMALL PASSENGER VESSELS CARRYING MORE THAN 150 PASSENGERS OR WITH OVERNIGHT ACCOMMODATIONS FOR MORE THAN 49 PASSENGERS MACHINERY INSTALLATION Specific Machinery Requirements § 119.450...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.gpo.gov/fdsys/pkg/CFR-2013-title46-vol2/pdf/CFR-2013-title46-vol2-sec64-63.pdf','CFR2013'); return false;" href="https://www.gpo.gov/fdsys/pkg/CFR-2013-title46-vol2/pdf/CFR-2013-title46-vol2-sec64-63.pdf"><span id="translatedtitle">46 CFR 64.63 - Minimum emergency <span class="hlt">venting</span> capacity.</span></a></p> <p><a target="_blank" href="http://www.gpo.gov/fdsys/browse/collectionCfr.action?selectedYearFrom=2013&page.go=Go">Code of Federal Regulations, 2013 CFR</a></p> <p></p> <p>2013-10-01</p> <p>... 46 Shipping 2 2013-10-01 2013-10-01 false Minimum emergency <span class="hlt">venting</span> capacity. 64.63 Section 64.63... AND CARGO HANDLING SYSTEMS Pressure Relief Devices and Vacuum Relief Devices for MPTs § 64.63 Minimum... device operating at a pressure not to exceed the test pressure: EC13NO91.047 where: Q=Minimum...</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li><a href="#" onclick='return showDiv("page_24");'>24</a></li> <li class="active"><span>25</span></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_25 --> <center> <div class="footer-extlink text-muted"><small>Some links on this page may take you to non-federal websites. 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