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1
Wu, Jing-Ying, Siou-Yan Lin, Jung-Fu Huang, Chen-Tung Arthur Chen, Jia-Jang Hung, Shao-Hung Peng, and Li-Lian Liu. "Differential feeding habits of the shallow-water hydrothermal vent crab Xenograpsus testudinatus correlate with their resident vent types at a scale of meters." Biogeosciences 20, no. 13 (July 12, 2023): 2693–706. http://dx.doi.org/10.5194/bg-20-2693-2023.
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Abstract. The shallow-water hydrothermal vents (SVs) located off Kueishan (KS) Island, Taiwan, are one of the world's most intensively studied vent systems. It has long been known that white vents (WVs) and yellow vents (YVs) differ in the color and composition of the vent plumes. The endemic vent crabs (Xenograpsus testudinatus) are abundant in both vent types, and ovigerous females migrate to the vent periphery with a distance of 100–200 m to release their offspring. However, most research on the vent crabs was associated with WV or unspecified vent areas. To increase our knowledge of the crabs dwelling in other vent types, we compared the feeding habits of the vent crabs living in WV and YV with 2 sampling months. Specifically, we examined the benthic community of WV and YV, the isotopic niche width, and protein expression patterns of the crabs from the two vents at a distance of 100 m and sampled in July and August 2010. The coverage of sessile organisms and low-mobility fauna in WV was more abundant than in YV, based on the survey in August 2010. The δ13C and δ15N values of crabs differed spatially and temporally (multivariate analysis of variance test; p<0.05). The niche width of the vent crabs from YV-August (0.88 ‰2) narrowed substantially compared to the rest, i.e., YV-July (2.94 ‰2), WV-July (2.88 ‰2), and WV-August (3.62 ‰2; p<0.05), respectively. Based on the protein expression patterns, the vent crabs exhibited three groups, i.e., WV-July and YV-July, WV-August, and YV-August, respectively. Our results indicated that the dwelling crabs were associated with their living vent, and within-vent variability was more noticeable in YV compared to WV. We suggested that vent crabs inhabit their resident vent. Even at a scale of meters, trans-vent movement is probably rare as an adaptation to minimize predation risk.
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Nike Bianchi, Carlo, Paul R. Dando, and Carla Morri. "Increased diversity of sessile epibenthos at subtidal hydrothermal vents: seven hypotheses based on observations at Milos Island, Aegean Sea." Advances in Oceanography and Limnology 2, no. 1 (June 17, 2011): 1. http://dx.doi.org/10.4081/aiol.2011.5314.
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Research on subtidal hydrothermal vent ecosystems at Milos, Hellenic Volcanic Arc (Aegean Sea), suggested that vent activity increased the species richness of sessile epibenthic assemblages. Based on 303 species found in 6 sites (3 close to vents, 3 farther away), the present paper uses correspondence analysis and species/samples curves to examine the species composition and richness of these assemblages. Differences due to vent proximity were more important than those due to bottom depth and distance from the shore. Diversity was confirmed to be higher near the vents, although none of the 266 species found at the vent sites can be considered as obligate vent-associated species. Seven different, although not mutually exclusive, hypotheses are discussed to explain the pattern of increased epibenthic species diversity at the vent sites, namely: (i) vents represent an intermediate disturbance, inducing mortality by the emission of toxic fluids; (ii) higher winter temperature allows for the occurrence of warm-water species, which add to the regional background; (iii) venting disrupts the homogeneity of the water bottom layer, increasing bottom roughness and hence habitat heterogeneity; (iv) deposition of minerals and enhanced bioconstruction by Ca enrichment increment habitat provision; (v) fluid emission induces advective mechanisms that favour recruitment; (vi) vents emit CO2, nutrients and trace elements that enhance primary productivity; and (vii) bacterial chemosynthesis add to photosynthesis to provide a diversity of food sources for the fauna.
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Zitoun, R., S. D. Connell, C. E. Cornwall, K. I. Currie, K. Fabricius, L. J. Hoffmann, M. D. Lamare, et al. "A unique temperate rocky coastal hydrothermal vent system (Whakaari–White Island, Bay of Plenty, New Zealand): constraints for ocean acidification studies." Marine and Freshwater Research 71, no. 3 (2020): 321. http://dx.doi.org/10.1071/mf19167.
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In situ effects of ocean acidification are increasingly studied at submarine CO2 vents. Here we present a preliminary investigation into the water chemistry and biology of cool temperate CO2 vents near Whakaari–White Island, New Zealand. Water samples were collected inside three vent shafts, within vents at a distance of 2m from the shaft and at control sites. Vent samples contained both seawater pH on the total scale (pHT) and carbonate saturation states that were severely reduced, creating conditions as predicted for beyond the year 2100. Vent samples showed lower salinities, higher temperatures and greater nutrient concentrations. Sulfide levels were elevated and mercury levels were at concentrations considered toxic at all vent and control sites, but stable organic and inorganic ligands were present, as deduced from Cu speciation data, potentially mediating harmful effects on local organisms. The biological investigations focused on phytoplankton, zooplankton and macroalgae. Interestingly, we found lower abundances but higher diversity of phytoplankton and zooplankton at sites in the direct vicinity of Whakaari. Follow-up studies will need a combination of methods and approaches to attribute observations to specific drivers. The Whakaari vents represent a unique ecosystem with considerable biogeochemical complexity, which, like many other vent systems globally, require care in their use as a model of ‘future oceans’.
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Kiel, Steffen. "A biogeographic network reveals evolutionary links between deep-sea hydrothermal vent and methane seep faunas." Proceedings of the Royal Society B: Biological Sciences 283, no. 1844 (December 14, 2016): 20162337. http://dx.doi.org/10.1098/rspb.2016.2337.
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Deep-sea hydrothermal vents and methane seeps are inhabited by members of the same higher taxa but share few species, thus scientists have long sought habitats or regions of intermediate character that would facilitate connectivity among these habitats. Here, a network analysis of 79 vent, seep, and whale-fall communities with 121 genus-level taxa identified sedimented vents as a main intermediate link between the two types of ecosystems. Sedimented vents share hot, metal-rich fluids with mid-ocean ridge-type vents and soft sediment with seeps. Such sites are common along the active continental margins of the Pacific Ocean, facilitating connectivity among vent/seep faunas in this region. By contrast, sedimented vents are rare in the Atlantic Ocean, offering an explanation for the greater distinction between its vent and seep faunas compared with those of the Pacific Ocean. The distribution of subduction zones and associated back-arc basins, where sedimented vents are common, likely plays a major role in the evolutionary and biogeographic connectivity of vent and seep faunas. The hypothesis that decaying whale carcasses are dispersal stepping stones linking these environments is not supported.
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Goffredi, Shana K., Shannon Johnson, Verena Tunnicliffe, David Caress, David Clague, Elva Escobar, Lonny Lundsten, et al. "Hydrothermal vent fields discovered in the southern Gulf of California clarify role of habitat in augmenting regional diversity." Proceedings of the Royal Society B: Biological Sciences 284, no. 1859 (July 19, 2017): 20170817. http://dx.doi.org/10.1098/rspb.2017.0817.
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Hydrothermal vent communities are distributed along mid-ocean spreading ridges as isolated patches. While distance is a key factor influencing connectivity among sites, habitat characteristics are also critical. The Pescadero Basin (PB) and Alarcón Rise (AR) vent fields, recently discovered in the southern Gulf of California, are bounded by previously known vent localities (e.g. Guaymas Basin and 21° N East Pacific Rise); yet, the newly discovered vents differ markedly in substrata and vent fluid attributes. Out of 116 macrofaunal species observed or collected, only three species are shared among all four vent fields, while 73 occur at only one locality. Foundation species at basalt-hosted sulfide chimneys on the AR differ from the functional equivalents inhabiting sediment-hosted carbonate chimneys in the PB, only 75 km away. The dominant species of symbiont-hosting tubeworms and clams, and peripheral suspension-feeding taxa, differ between the sites. Notably, the PB vents host a limited and specialized fauna in which 17 of 26 species are unknown at other regional vents and many are new species. Rare sightings and captured larvae of the ‘missing’ species revealed that dispersal limitation is not responsible for differences in community composition at the neighbouring vent localities. Instead, larval recruitment-limiting habitat suitability probably favours species differentially. As scenarios develop to design conservation strategies around mining of seafloor sulfide deposits, these results illustrate that models encompassing habitat characteristics are needed to predict metacommunity structure.
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BURON, I. de, and S. MORAND. "Deep-sea hydrothermal vent parasites: why do we not find more?" Parasitology 128, no. 1 (January 2004): 1–6. http://dx.doi.org/10.1017/s0031182003004347.
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While parasitism is recognized as the most common mode of existence on the planet, and hosts from virtually all ecosystems have been studied, very little is known about the parasites found in deep-sea hydrothermal vent ecosystems and even less is known about their ecology, evolution, and effects on their hosts. The purpose of this work is to offer a comprehensive review of our state of knowledge about parasitism in the deep-sea vents and to pose and address specific questions for future studies. Because the deep-sea environment itself may influence the number and types of parasites found in the vents, non-vent (below 1000 m) and vent deep-sea data were used in a comparative analysis to account for this factor as a potential major determinant of the parasite fauna in the vents. Based upon analysis of these data, it is highly likely that the reason why so few parasites are currently known from deep-sea vents, even given the low diversity of hosts in this ecosystem, is simply that their inconspicuous nature has caused them to be overlooked by vent biologists.
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Mei, Kang, Deli Wang, Yan Jiang, Mengqiu Shi, Chen-Tung Arthur Chen, Yao Zhang, and Kai Tang. "Transformation, Fluxes and Impacts of Dissolved Metals from Shallow Water Hydrothermal Vents on Nearby Ecosystem Offshore of Kueishantao (NE Taiwan)." Sustainability 14, no. 3 (February 3, 2022): 1754. http://dx.doi.org/10.3390/su14031754.
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Hydrothermal vents are one of the important sources of major or trace elements in the ocean. The elemental fluxes, however, may be dynamic due to coastal processes and hydrothermal plumes, especially in shallow-water hydrothermal vents. We collected water samples by using the trace-metal clean technique inside and outside two shallow-water hydrothermal vents (white vent: low temperature, high pH; and yellow vent: high temperature, low pH) off Kueishantao Islet, Taiwan, China via SCUBA divers. We analyzed these samples for their hydro-chemical parameters and dissolved elements (Fe, Mn, Mg, V, Cu, and Mo) thereafter. Our results show that dissolved metals’ concentrations were significantly different between the two vents, with higher Mn and Fe in the White Vent than in the Yellow Vent, likely due to the decreased affinity of the dissolved metals for particles in the white vent. We estimated the plume fluxes of dissolved metals from the hydrothermal mouth by multiplying in situ hydrothermal discharge flowrates with metals’ concentrations inside the vents, which were: 1.09~7.02 × 104 kg Mg, 0.10~1.23 kg Fe, 0.08~28 kg Mn, 33.4~306 g V, 2.89~77.7 g Cu, and 54.3~664 g Mo, annually. The results further indicate that such plumes probably have impacted nearby seawater due to coastal currents and particle desorption during transport. Furthermore, the concentrations of biogenic elements could be further modified in seawater, and potentially impact nearby ecosystems on a larger scale. Our study provides information with which to further understand metal redeployment in submarine shallow nearby ecosystems.
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Yuki, M. S., J. R. Parsons, and R. J. Krane. "An Investigation of the Passive Cooling of Table Model Television Receivers." Journal of Electronic Packaging 112, no. 4 (December 1, 1990): 279–87. http://dx.doi.org/10.1115/1.2904380.
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Economic and reliability considerations lead to the adoption of passive techniques for cooling by a combination of natural convection and radiation heat transfer. In order to facilitate the cooling by natural convection, thermal design engineers commonly incorporate vent openings in the walls of a receiver cabinet. Unfortunately, natural convection flows in complex, vented enclosures are presently not well understood and designers must employ “cut and try” methodologies to determine the sizes and locations of vent openings. Since vent openings are expensive to incorporate in consumer electronic products, it was decided to develop the techniques that would enable thermal designers to minimize the number of vent openings in a TV cabinet and maximize the effectiveness of those vents that are employed. Thus, the present study represents the first step in a rational program to develop the tools that will enable engineers to optimize the thermal design of a table model television receiver. In this initial work, experiments were performed to determine the effects of vent size and location on component cooling in a representative table model receiver. Vents were systematically blocked until the set was operated in a completely sealed condition. Measurements of component, air, and cabinet wall temperatures and the results of flow visualization experiments were used to assess the effects of various combinations of vent openings on the natural convection cooling of the receiver. Results indicate that: (1) the present design of the vent system of a representative, commercially available table model television receiver is adequate, but has not been optimized, and (2) significant improvements in the design of the vent could be achieved; that is, improved component cooling could be obtained with fewer vent openings. The results of this work, which should be directly applicable by thermal designers, will also serve to experimentally verify numerical models of the natural convection flows through television receivers that are currently under development.
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Li, Xiaokang, and Yongbin Yang. "Study on the Influence of Smoke Vent Arrangement on the Natural Smoke Exhaust Effect in Urban Traffic Link Tunnels." Fire 8, no. 2 (January 26, 2025): 49. https://doi.org/10.3390/fire8020049.
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Urban traffic link tunnels have a high traffic flow and fire risk, and a reasonable smoke exhaust design is significant to a tunnel’s safety. The distance between smoke vents is one of the critical parameters of smoke extraction systems. Based on Froude’s similarity principle, a 1:12 reduced-scale UTLT smoke control research experimental platform was built to experimentally study the influence of the smoke vent arrangement on the smoke exhaust effect, and a smoke mass flow prediction model was established accordingly. Results show that with the increase in the smoke vent distance, the driving force generated by the stack effect is weakened, resulting in the reduction in smoke extraction and a decrease in the efficiency of the smoke vent; the overall mass flow of the smoke vent first increases and then decreases, and a distance between the smoke vents of 20 m can achieve a better smoke exhaust effect.
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Cubelio, Sherine Sonia, Shinji Tsuchida, and Seiichi Watanabe. "New species ofMunidopsis(Decapoda: Anomura: Galatheidae) from hydrothermal vent areas of Indian and Pacific Oceans." Journal of the Marine Biological Association of the United Kingdom 88, no. 1 (February 2007): 111–17. http://dx.doi.org/10.1017/s0025315408000180.
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Two new species ofMunidopsisfrom the hydrothermal vent area, Kairei Field, Central Indian Ridge in the Indian Ocean and Forecast Vent Field, Mariana Back Arc Basin in the west Pacific are described and illustrated. Their affinities to closely related species are discussed. The number ofMunidopsisspecies associated to hydrothermal vents in the world oceans has increased to 16. The habitat of new species is briefly described and the pattern of abundance of vent associatedMunidopsisis briefly discussed.
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De Vogeleer, Gerlinde, Peter Demeyer, Philippe Van Overbeke, and Jan G. Pieters. "Assessing Airflow Distribution in Vents of a Naturally Ventilated Test Facility Using Reference Air Velocity Measurements." Transactions of the ASABE 61, no. 3 (2018): 1065–76. http://dx.doi.org/10.13031/trans.12458.
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Abstract. Emission measurement in naturally ventilated buildings is a complex task because wind conditions can change quickly, inducing high spatial and temporal variations in the air velocity and pollutant concentration at the vent level. Simply taking the product of differential pollutant concentration and airflow rate may generate inaccurate results because the limited number of measurement locations usually fails to correctly reflect the velocity and concentration distributions in the vents. To assess the predictability of the airflow distribution in the vents of a naturally ventilated building, detailed measurements were conducted in the vents. Linear regression was applied to velocity measurements taken in the vents and at a 10 m mast (meteomast) located 20 m away. The detailed airflow measurements were used to validate statistical models. Results showed that the velocity distribution in the ridge vent could be modeled accurately and precisely for all wind directions (R2 > 89%). Models for unidirectional airflows showed high predictability for the side vent (R2 > 92%). Models for bidirectional airflows showed good predictability for the windward side when the air flowed in the same direction as the outside wind (R2 > 88%) but showed less accurate results for the leeward side as well as for airflows moving in the opposite direction to the outside wind. For all models and wind directions, the most important input variable was the velocity component measured perpendicular to the vents at the meteomast. The importance of the velocity component measured parallel to the vents increased near the edges of the vent when the vent was on the windward side but did not reach the importance of the perpendicular component. The results confirmed the importance of using different models for unidirectional and bidirectional airflows to obtain accurate airflow assessments. Keywords: Airflow rate distribution, Mock-up building, Natural ventilation, Ultrasonic anemometer.
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Park, Yu Mi, Chi Young Lee, and Jun-Ho Choi. "Investigation on Effect of Ceiling Vent Location on Fire Phenomena in Enclosure with Side and Ceiling Vents." Fire Science and Engineering 36, no. 3 (June 30, 2022): 1–10. http://dx.doi.org/10.7731/kifse.7d71242e.
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In this study, the effect of ceiling vent location on the fire phenomena in the enclosure with side and ceiling vents was numerically investigated. As the ceiling vent location, Case F, Case F-M, Case M, Case M-B, and Case B were tested, and their distances from the side vent to the center of each vent were 0.265, 0.525, 0.750, 0.975, and 1.235 m, respectively. Among these cases, Case M-B showed the lowest temperature distribution in the enclosure and smoke layer temperature, the thinnest smoke layer, and the highest mass flow rate of outflow through the ceiling vent. One of possible reasons for these results is owing to the fact that the behavior of fire plume is changed by the inflow through the side vent. As the visualization result of temperature distribution, to determine the ceiling vent location for the improvement of smoke ventilation performance, it can be important to predict the amount of fire plume inclination by inflow through the side vent and the height of inclined fire plume region. To predict the amount of fire plume inclination by inflow through the side vent, the previous correlations of flame angle were assessed, which under-estimated the fire plume inclination of present numerical simulation.
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Song, Kai, Wangru Wei, Shiqiang Wu, Luchen Zhang, and Zhengli Yang. "Numerical investigation on effect of air vent on air supply." AIP Advances 12, no. 8 (August 1, 2022): 085221. http://dx.doi.org/10.1063/5.0101976.
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An improper design of an air vent will not only cause waste of resources but also seriously threaten the safety of the spillway tunnel. The present study analyzes the effects of the area and position of the air vent on the air supply, using the volume of fluid method with the k–ε turbulence model. The air speed in the air vent will decrease with an increase in the area, but the quantity of air supplied will increase. When the area of air vents is equal to the tunnel residual, the air supply capacity of the air vent reaches the maximum. A relationship between the quantity of air supplied and the area of the air vent is put forward, and the error with the prototype observation result is about 10%. The distribution of negative pressure in the tunnel may be improved by arranging the air vent in a proper position; the quantity of air supplied also decreases as the distance between the air vent and the pressurized conduit increases. In general, it is more advantageous to position the air vent upstream. These results provide a reference for the air ventilation design in hydraulic engineering.
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Cho, Boongho, Sook-Jin Jang, Hee-seung Hwang, and Taewon Kim. "Convergent Evolution of Armor: Thermal Resistance in Deep-Sea Hydrothermal Vent Crustaceans." Biology 13, no. 12 (November 21, 2024): 956. http://dx.doi.org/10.3390/biology13120956.
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Organisms occupy diverse ecological niches worldwide, each with characteristics finely evolved for their environments. Crustaceans residing in deep-sea hydrothermal vents, recognized as one of Earth’s extreme environments, may have adapted to withstand severe conditions, including elevated temperatures and pressure. This study compares the exoskeletons of two vent crustaceans (bythograeid crab Austinograea sp. and squat lobster Munidopsis lauensis) with four coastal species (Asian paddle crabs, blue crab, hermit crab, and mantis shrimp) to identify traits influenced by vent environments. The goal was to identify distinctive exoskeletal characteristics commonly observed in vent crustaceans, resulting from their exposure to severe abiotic factors, including elevated temperatures and pressures, found in vent environments. Results show that the exoskeletons of vent crustaceans demonstrated significantly enhanced thermal stability compared to coastal species. These vent crustaceans consistently featured exoskeletons characterized by a reduced proportion of volatile components, such as water, and an increased proportion of CaCO3, compared with coastal crustaceans. Furthermore, vent crustaceans lacked carotenoid pigments that had low heat resistance. However, no apparent differences were observed in the mechanical properties. Our findings suggest that the similar composition of exoskeletons in vent crustaceans evolved convergently to withstand high temperatures.
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Bates, Amanda E. "Size- and sex-based habitat partitioning by Lepetodrilus fucensis near hydrothermal vents on the Juan de Fuca Ridge, Northeast Pacific." Canadian Journal of Fisheries and Aquatic Sciences 65, no. 11 (November 2008): 2332–41. http://dx.doi.org/10.1139/f08-139.
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This study examines habitat partitioning by a hydrothermal vent limpet, Lepetodrilus fucensis, along environmental gradients and among vents with differing levels of flux. To test for spatial patterns in size structure, two distances from isolated vent flows were sampled (0–25 cm and 51–75 cm). Lepetodrilus fucensis displays a size gradient: juveniles are rare in flow (relative abundance < 5%, density = 56 ± 46 individuals·dm–2) and abundant peripherally (>95%, 2616 ± 2002 individuals·dm–2). Next, sex-based habitat partitioning was examined. High flux locations are female-biased (proportion male = 0.34 ± 0.07), whereas males are overrepresented peripherally and at waning vents (0.64 ± 0.08). The spatial mismatch between the sexes within a vent is driven by differential habitat occupation at decimetre scales. One hypothesis to explain this pattern is that females suffer a higher cost of reproduction and outcompete males for habitats with high food availability. Indeed, relatively higher percentages of females in waning vents had empty gonads in comparison with males (32%–78% vs. 0%–16%, respectively). Furthermore, females transplanted to the vent periphery for one year displayed much lower survivorship than males (2% vs. 27%). This finding suggests that differential survivorship between the sexes when food is limited can yield male-biased populations at waning vents.
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Djurhuus, Anni, Svein-Ole Mikalsen, Helge-Ansgar Giebel, and Alex D. Rogers. "Cutting through the smoke: the diversity of microorganisms in deep-sea hydrothermal plumes." Royal Society Open Science 4, no. 4 (April 2017): 160829. http://dx.doi.org/10.1098/rsos.160829.
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There are still notable gaps regarding the detailed distribution of microorganisms between and within insular habitats such as deep-sea hydrothermal vents. This study investigates the community composition of black smoker vent microorganisms in the Southern Hemisphere, and changes thereof along a spatial and chemical gradient ranging from the vent plume to surrounding waters. We sampled two hydrothermal vent fields, one at the South West Indian Ridge (SWIR), the other at the East Scotia Ridge (ESR). Samples were collected across vent fields at varying vertical distances from the origin of the plumes. The microbial data were sequenced on an Illumina MiSeq platform for the 16SrRNA gene. A substantial amount of vent-specific putative chemosynthetic microorganisms were found, particularly in samples from focused hydrothermal venting. Common vent-specific organisms from both vent fields were the genera Arcobacter , Caminibacter and Sulfurimonas from the Epsilonproteobacteria and the SUP05 group from the Gammaproteobacteria. There were no major differences in microbial composition between SWIR and ESR for focused plume samples. However, within the ESR the diffuse flow and focused samples differed significantly in microbial community composition and relative abundance. For Epsilonproteobacteria, we found evidence of niche-specificity to hydrothermal vent environments. This taxon decreased in abundance by three orders of magnitude from the vent orifice to background water. Epsilonproteobacteria distribution followed a distance–decay relationship as vent-effluents mixed with the surrounding seawater. This study demonstrates strong habitat affinity of vent microorganisms on a metre scale with distinct environmental selection.
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Bonnivard, Eric, Olivier Catrice, Juliette Ravaux, Spencer C. Brown, and Dominique Higuet. "Survey of genome size in 28 hydrothermal vent species covering 10 families." Genome 52, no. 6 (June 2009): 524–36. http://dx.doi.org/10.1139/g09-027.
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Knowledge of genome size is a useful and necessary prerequisite for the development of many genomic resources. To better understand the origins and effects of DNA gains and losses among species, it is important to collect data from a broad taxonomic base, but also from particular ecosystems. Oceanic thermal vents are an interesting model to investigate genome size in very unstable environments. Here we provide data estimated by flow cytometry for 28 vent-living species among the most representative from different hydrothermal vents. We also report the genome size of closely related coastal decapods. Haploid C-values were compared with those previously reported for species from corresponding orders or infraorders. This is the first broad survey of 2C values in vent organisms. Contrary to expectations, it shows that certain hydrothermal vent species have particularly large genomes. The vent squat lobster Munidopsis recta has the largest genome yet reported for any anomuran: 2C = 31.1 pg = 30.4 × 109 bp. In several groups, such as Brachyura, Phyllodocida, and Veneroida, vent species have genomes that clearly rank at the high end of published values for each group. We also describe the highest DNA content yet recorded for the Brachyura (coastal crabs Xantho pilipes and Necora puber ). Finally, analysis of genome size variation across populations revealed unexpected intraspecific variation in the vent shrimp Mirocaris fortunata that could not be attributed simply to ploidy changes.
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Linse, Katrin, Jonathan T. Copley, Douglas P. Connelly, Robert D. Larter, David A. Pearce, Nick V. C. Polunin, Alex D. Rogers, et al. "Fauna of the Kemp Caldera and its upper bathyal hydrothermal vents (South Sandwich Arc, Antarctica)." Royal Society Open Science 6, no. 11 (November 2019): 191501. http://dx.doi.org/10.1098/rsos.191501.
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Faunal assemblages at hydrothermal vents associated with island-arc volcanism are less well known than those at vents on mid-ocean ridges and back-arc spreading centres. This study characterizes chemosynthetic biotopes at active hydrothermal vents discovered at the Kemp Caldera in the South Sandwich Arc. The caldera hosts sulfur and anhydrite vent chimneys in 1375–1487 m depth, which emit sulfide-rich fluids with temperatures up to 212°C, and the microbial community of water samples in the buoyant plume rising from the vents was dominated by sulfur-oxidizing Gammaproteobacteria. A total of 12 macro- and megafaunal taxa depending on hydrothermal activity were collected in these biotopes, of which seven species were known from the East Scotia Ridge (ESR) vents and three species from vents outside the Southern Ocean. Faunal assemblages were dominated by large vesicomyid clams, actinostolid anemones, Sericosura sea spiders and lepetodrilid and cocculinid limpets, but several taxa abundant at nearby ESR hydrothermal vents were rare such as the stalked barnacle Neolepas scotiaensis . Multivariate analysis of fauna at Kemp Caldera and vents in neighbouring areas indicated that the Kemp Caldera is most similar to vent fields in the previously established Southern Ocean vent biogeographic province, showing that the species composition at island-arc hydrothermal vents can be distinct from nearby seafloor-spreading systems. δ 13 C and δ 15 N isotope values of megafaunal species analysed from the Kemp Caldera were similar to those of the same or related species at other vent fields, but none of the fauna sampled at Kemp Caldera had δ 13 C values, indicating nutritional dependence on Epsilonproteobacteria, unlike fauna at other island-arc hydrothermal vents.
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Nye, Verity, Jon Copley, Katrin Linse, and Sophie Plouviez. "Iheyaspira bathycodon new species (Vetigastropoda: Trochoidea: Turbinidae: Skeneinae) from the Von Damm Vent Field, Mid-Cayman Spreading Centre, Caribbean." Journal of the Marine Biological Association of the United Kingdom 93, no. 4 (August 13, 2012): 1017–24. http://dx.doi.org/10.1017/s0025315412000823.
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Iheyaspira bathycodon sp. nov. is described from the Von Damm Vent Field on the world's deepest spreading centre, the Mid-Cayman Spreading Centre (MCSC), Caribbean, at 2300 m depth. The new species is defined and illustrated from 11 specimens, with brief notes on habitat and known distribution. Molecular phylogenetic data from partial COI mDNA, 16S rDNA and nuclear 18S rDNA regions are used to analyse the species’ phylogenetic position and its morphology is compared with previously described skeneid and vent taxa. The new species is distinguished from the most closely allied vent species, Iheyaspira lequios Okutani, Sasaki & Tsuchida, 2000 by morphological differences in radula diagnosis and appendage structure of the head-foot. Iheyaspira bathycodon sp. nov. is the tenth turbinid to be described from a hydrothermal-vent environment and the second species to be named from recently discovered hydrothermal vents on the MCSC. Determining the faunal composition of assemblages at the vent fields of the MCSC will help to elucidate the vent biogeography of the region.
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López-Martínez, Molina-Aiz, Valera-Martínez, López-Martínez, Peña-Fernández, and Espinoza-Ramos. "Application of Semi-Empirical Ventilation Models in A Mediterranean Greenhouse with Opposing Thermal and Wind Effects. Use of Non-Constant Cd (Pressure Drop Coefficient Through the Vents) and Cw (Wind Effect Coefficient)." Agronomy 9, no. 11 (November 10, 2019): 736. http://dx.doi.org/10.3390/agronomy9110736.
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The present work analyses the natural ventilation of a multi-span greenhouse with one roof vent and two side vents by means of sonic anemometry. Opening the roof vent to windward, one side vent to leeward, and the other side vents to windward (this last vent obstructed by another greenhouse), causes opposing thermal GT (m3 s−1) and wind effects Gw (m3 s−1), as outside air entering the greenhouse through the roof vent circulates downward, contrary to natural convection due to the thermal effect. In our case, the ventilation rate RM (h−1) in a naturally ventilated greenhouse fits a second order polynomial with wind velocity uo (RM = 0.37 uo2 + 0.03 uo + 0.75; R2 = 0.99). The opposing wind and thermal effects mean that ventilation models based on Bernoulli’s equation must be modified in order to add or subtract their effects accordingly—Model 1, in which the flow is driven by the sum of two independent pressure fields GM1=GT2±Gw2, or Model 2, in which the flow is driven by the sum of two independent fluxes GM2=GT±Gw. A linear relationship has been obtained, which allows us to estimate the discharge coefficient of the side vents (CdVS) and roof vent (CdWR) as a function of uo [CdVS = 0.028 uo + 0.028 (R2 = 0.92); CdWR = 0.036 uo + 0.040 (R2 = 0.96)]. The wind effect coefficient Cw was determined by applying models M1 and M2 proved not to remain constant for the different experiments, but varied according to the ratio uo/∆Tio0.5 or δ [CwM1 = exp(-2.693 + 1.160/δ) (R2 = 0.94); CwM2 = exp(−2.128 + 1.264/δ) (R2 = 0.98)].
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Rezanejadzanjani, Behdad, and Paul G. O’Brien. "EVALUATION OF SMART BOOSTER FANS AND DAMPERS FOR ADVANCED HVAC SYSTEMS." Journal of Green Building 16, no. 2 (March 1, 2021): 115–27. http://dx.doi.org/10.3992/jgb.16.2.115.
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ABSTRACT There is potential to significantly reduce CO2 emissions by increasing the efficiency and reducing the duty cycle of HVAC systems by using smart booster fans and dampers. Smart booster fans fit in the vents within a home, operating quietly on low power (2W) to augment HVAC systems and improve their performance. In this study, a prototype duct system is used to measure and evaluate the ability for smart booster fans and dampers to control airflow to different vents for the purpose of increasing the efficiency of HVAC systems. Four case studies were evaluated: an HVAC system (1) without any fans or dampers, (2) with a fan installed in one vent, but without any dampers, (3) with dampers installed at the vents, but without any fans, and (4) with both fan and dampers installed. The results from both the experimental and numerical evaluation show that the smart booster fan and dampers can significantly improve the airflow at a vent that is underperforming. For example, the airflow at the last vent in a ducting branch was increased from 17 to 37 CFM when a smart booster fan was installed at this vent. Results from the numerical analysis show that for the case of an underperforming vent during the winter season the HVAC running time may be reduced from 24 hr/day to 5.6 hr/day. Furthermore, results from the numerical analysis show the HVAC running time is further reduced to 4.5 hr/day for cases 3 and 4.
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Yang, Jin-Shu, Bo Lu, Dian-Fu Chen, Yan-Qin Yu, Fan Yang, Hiromichi Nagasawa, Shinji Tsuchida, Yoshihiro Fujiwara, and Wei-Jun Yang. "When Did Decapods Invade Hydrothermal Vents? Clues from the Western Pacific and Indian Oceans." Molecular Biology and Evolution 30, no. 2 (October 16, 2012): 305–9. http://dx.doi.org/10.1093/molbev/mss224.
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Abstract Hydrothermal vents are typically located in midocean ridges and back-arc basins and are usually generated by the movement of tectonic plates. Life thrives in these environments despite the extreme conditions. In addition to chemoautotrophic bacteria, decapod crustaceans are dominant in many of the hydrothermal vents discovered to date. Contrary to the hypothesis that these species are remnants of relic fauna, increasing evidence supports the notion that hydrothermal vent decapods have diversified in more recent times with previous research attributing the origin of alvinocarid shrimps to the Miocene. This study investigated seven representative decapod species from four hydrothermal vents throughout the Western Pacific and Indian Oceans. A partitioned mix-model phylogenomic analysis of mitochondrial DNA produced a consistent phylogenetic topology of these vent-endemic species. Additionally, molecular dating analysis calibrated using multiple fossils suggested that both bythograeid crabs and alvinocarid shrimps originated in the late Mesozoic and early Cenozoic. Although of limited sampling, our estimates support the extinction/repopulation hypothesis, which postulates recent diversification times for most hydrothermal vent species due to their mass extinction by global deep-water anoxic/dysoxic events during the Late Cretaceous and Early Tertiary. The continental-derived property of the West Pacific province is compatible with the possibility that vent decapods diversified from ancestors from shallow-water regions such as cold seeps. Our results move us a step closer toward understanding the evolutionary origin of hydrothermal vent species and their distribution in the Western Pacific–Indian Ocean Region.
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Hu, Sarah K., Erica L. Herrera, Amy R. Smith, Maria G. Pachiadaki, Virginia P. Edgcomb, Sean P. Sylva, Eric W. Chan, Jeffrey S. Seewald, Christopher R. German, and Julie A. Huber. "Protistan grazing impacts microbial communities and carbon cycling at deep-sea hydrothermal vents." Proceedings of the National Academy of Sciences 118, no. 29 (July 15, 2021): e2102674118. http://dx.doi.org/10.1073/pnas.2102674118.
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Microbial eukaryotes (or protists) in marine ecosystems are a link between primary producers and all higher trophic levels, and the rate at which heterotrophic protistan grazers consume microbial prey is a key mechanism for carbon transport and recycling in microbial food webs. At deep-sea hydrothermal vents, chemosynthetic bacteria and archaea form the base of a food web that functions in the absence of sunlight, but the role of protistan grazers in these highly productive ecosystems is largely unexplored. Here, we pair grazing experiments with a molecular survey to quantify protistan grazing and to characterize the composition of vent-associated protists in low-temperature diffuse venting fluids from Gorda Ridge in the northeast Pacific Ocean. Results reveal protists exert higher predation pressure at vents compared to the surrounding deep seawater environment and may account for consuming 28 to 62% of the daily stock of prokaryotic biomass within discharging hydrothermal vent fluids. The vent-associated protistan community was more species rich relative to the background deep sea, and patterns in the distribution and co-occurrence of vent microbes provide additional insights into potential predator–prey interactions. Ciliates, followed by dinoflagellates, Syndiniales, rhizaria, and stramenopiles, dominated the vent protistan community and included bacterivorous species, species known to host symbionts, and parasites. Our findings provide an estimate of protistan grazing pressure within hydrothermal vent food webs, highlighting the important role that diverse protistan communities play in deep-sea carbon cycling.
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Diaz-Recio Lorenzo, Coral, Tasnim Patel, Eve-Julie Arsenault-Pernet, Camille Poitrimol, Didier Jollivet, Pedro Martinez Arbizu, and Sabine Gollner. "Highly structured populations of deep-sea copepods associated with hydrothermal vents across the Southwest Pacific, despite contrasting life history traits." PLOS ONE 18, no. 11 (November 6, 2023): e0292525. http://dx.doi.org/10.1371/journal.pone.0292525.
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Hydrothermal vents are extreme environments, where abundant communities of copepods with contrasting life history traits co-exist along hydrothermal gradients. Here, we discuss how these traits may contribute to the observed differences in molecular diversity and population genetic structure. Samples were collected from vent locations across the globe including active ridges and back-arc basins and compared to existing deep-sea hydrothermal vent and shallow water data, covering a total of 22 vents and 3 non-vent sites. A total of 806 sequences of mtDNA from the Cox1 gene were used to reconstruct the phylogeny, haplotypic relationship and demography within vent endemic copepods (Dirivultidae, Stygiopontius spp.) and non-vent-endemic copepods (Ameiridae, Miraciidae and Laophontidae). A species complex within Stygiopontius lauensis was studied across five pacific back-arc basins at eight hydrothermal vent fields, with cryptic species being restricted to the basins they were sampled from. Copepod populations from the Lau, North Fiji and Woodlark basins are undergoing demographic expansion, possibly linked to an increase in hydrothermal activity in the last 10 kya. Highly structured populations of Amphiascus aff. varians 2 were also observed from the Lau to the Woodlark basins with populations also undergoing expansion. Less abundant harpacticoids exhibit little to no population structure and stable populations. This study suggests that similarities in genetic structure and demography may arise in vent-associated copepods despite having different life history traits. As structured meta-populations may be at risk of local extinction should major anthropogenic impacts, such as deep-sea mining, occur, we highlight the importance of incorporating a trait-based approach to investigate patterns of genetic connectivity and demography, particularly regarding area-based management tools and environmental management plans.
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Csotonyi, Julius T., Erko Stackebrandt, and Vladimir Yurkov. "Anaerobic Respiration on Tellurate and Other Metalloids in Bacteria from Hydrothermal Vent Fields in the Eastern Pacific Ocean." Applied and Environmental Microbiology 72, no. 7 (July 2006): 4950–56. http://dx.doi.org/10.1128/aem.00223-06.
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ABSTRACT This paper reports the discovery of anaerobic respiration on tellurate by bacteria isolated from deep ocean (1,543 to 1,791 m) hydrothermal vent worms. The first evidence for selenite- and vanadate-respiring bacteria from deep ocean hydrothermal vents is also presented. Enumeration of the anaerobic metal(loid)-resistant microbial community associated with hydrothermal vent animals indicates that a greater proportion of the bacterial community associated with certain vent fauna resists and reduces metal(loid)s anaerobically than aerobically, suggesting that anaerobic metal(loid) respiration might be an important process in bacteria that are symbiotic with vent fauna. Isolates from Axial Volcano and Explorer Ridge were tested for their ability to reduce tellurate, selenite, metavanadate, or orthovanadate in the absence of alternate electron acceptors. In the presence of metal(loid)s, strains showed an ability to grow and produce ATP, whereas in the absence of metal(loid)s, no growth or ATP production was observed. The protonophore carbonyl cyanide m-chlorophenylhydrazone depressed metal(loid) reduction. Anaerobic tellurate respiration will be a significant component in describing biogeochemical cycling of Te at hydrothermal vents.
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Chamberlain, Steven C. "Vision in hydrothermal vent shrimp." Philosophical Transactions of the Royal Society of London. Series B: Biological Sciences 355, no. 1401 (September 29, 2000): 1151–54. http://dx.doi.org/10.1098/rstb.2000.0657.
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Bresiliid shrimp from hydrothermal vents on the Mid–Atlantic Ridge have non–imaging eyes adapted for photodetection in light environments of very low intensity. Comparison of retinal structures between both vent shrimp and surface–dwelling shrimp with imaging eyes, and between juvenile and adult vent shrimp, suggests that vent shrimp have evolved from ancestors that lived in a light environment with bright cyclic lighting. Whether the vent shrimp live in swarms and have large dorsal eyes or live in sparse groupings and have large anterior eyes, the basic retinal adaptations are the same across species. Retinal adaptations in adult vent shrimp include the loss of dioptrics, enlargement of both the rhabdomeral segment of the photoreceptors and the light–sensitive rhabdomere therein, attenuation of the arhabdomeral segment of the photoreceptors, reduction of black screening pigment, development of a white diffusing layer behind the photoreceptors, and the loss of rhabdom turnover.
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Akrami, Mohammad, Akbar A. Javadi, Matthew J. Hassanein, Raziyeh Farmani, Mahdieh Dibaj, Gavin R. Tabor, and Abdelazim Negm. "Study of the Effects of Vent Configuration on Mono-Span Greenhouse Ventilation Using Computational Fluid Dynamics." Sustainability 12, no. 3 (January 29, 2020): 986. http://dx.doi.org/10.3390/su12030986.
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The rise in the human population, its density and scarcity of resources require cost-effective solutions for sustainable energy and water resources. Smart and sustainable agriculture is one important factor for future green cities to tackle climate change as a cost-effective solution to save energy and water. However, greenhouses (GH) require consistent ventilation due to their internal temperatures, and this can be an energy-intensive operation. Therefore, it is necessary to analyse the potential factors involved. In this study, the effect of vent configuration of a mono-span greenhouse with roof and side vents at low wind speeds was investigated using computational fluid dynamics (CFD). The validated simulations were then performed on different models to analyse the effects of the vents’ locations on the ventilation requirements. The side vents were found to contribute most to the ventilation. The position of the side vent was found to affect the convection loop in the greenhouse and the air velocity at the plant level. The humidity was shown to be highest under the windward side vent. The roof vent was found to affect the temperature and air velocity in the roof of the greenhouse but had very little effect on the distributions at the plant level.
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Imran, Mohammad, Rajpreet Dhaliwal, and Syed H. Masood. "Thermal Analysis of a Bi-Metallic Chill Vent for High Pressure Die Casting." Materials Science Forum 654-656 (June 2010): 791–94. http://dx.doi.org/10.4028/www.scientific.net/msf.654-656.791.
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High pressure die casting (HPDC) is widely used for manufacturing aluminum parts in automotive industry. In high pressure die casting mold, chill vents are used to allow residual air and gases to exhaust out from the mold cavity. The objective of this paper is to design and develop a bi- metallic chill vent for high pressure die casting using copper alloy material having high thermal conductivity, coated with steel layer on the surface. Transient thermal analysis was carried out using ANSYS software, and temperature distribution was compared with bimetallic and tool steel chill vents. The results show a faster extraction of heat in bi-metallic chill vent than that with steel. This paper also presents the effect of varying internal diameter of cooling channel in chill vent cooling.
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Gallant, Elisabeth, Lawrence Cole, Charles Connor, Amy Donovan, Danielle Molisee, Julie Morin, Rory Walshe, and Paul Wetmore. "Modelling eruptive event sources in distributed volcanic fields." Volcanica 4, no. 2 (December 30, 2021): 325–43. http://dx.doi.org/10.30909/vol.04.02.325343.
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Vent opening hazard models are routinely used as inputs for assessing distal volcanic hazards (lava flows, tephra fallout) in distributed volcanic fields. These vent opening hazard models have traditionally relied on the location of mapped vents; seldom have they taken into account how vents are linked in space and time. We show that inputs needed to appropriately model distal hazards are fundamentally different than thoses required to model near-vent hazards (ground deformation). We provide a computational model to obtain more appropriate eruptive source parameters (ESPs) for distal volcanic hazard sources and show the utility of our code through three examples. The code's strength is that it links events based on the spatio-temporal relationships of vents through heirarchical clustering. The development of the code and its strenghts and weaknesses are discussed. This work challenges previous ideas about ESPs and we hope this work leads to further improvement in hazard assessment methods.
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Liu, Lei, Lianghan Zhang, Zhongxu Kang, and Kun Yao. "Study on the Thermal Environment Inside a Fully-Enclosed Subway Noise Barrier." E3S Web of Conferences 143 (2020): 01044. http://dx.doi.org/10.1051/e3sconf/202014301044.
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The thermal environment inside a fully-enclosed subway noise barrier shall be designed according to underground section tunnel standards. This article constructs a model using practical examples, simulates calculations on fully-enclosed noise barrier installations both with and without air vents via a threedimensional numerical simulation method, and then conducts a comparative analysis of the effects noise barrier lengths and air vent widths have on an internal thermal environment. The calculation results show that when the length of the fully-enclosed noise barrier without air vents was 100m, the internal thermal environment exceeded the limit; as the width of the air vents increased, the temperature in the internal environment gradually decreased, but the reduction was less once the air vent width exceeded 2 m; When the top air vent width was 2 m, and the noise barrier length was 100m, the thermal environment was found to meet requirements. As the noise barrier length increased, the internal air temperature exceeded the standards by varying degrees.
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Baker, RR, and LS Lewis. "A Review of the Incidence and Consequences of Cigarette Filter Vent Blocking Among Smokers." Beiträge zur Tabakforschung International/Contributions to Tobacco Research 19, no. 4 (January 1, 2001): 209–28. http://dx.doi.org/10.2478/cttr-2013-0709.
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AbstractVent blocking, the covering of the filter ventilation zone on a cigarette during smoking, is a potentially important aspect of smoking behavior. Various techniques have been used to assess the incidence of vent blocking, and widely different views have been expressed on its importance. Studies relevant to filter vent blocking have been reviewed with two overall objectives: to examine critically the evidence on the occurrence of vent blocking and to assess the effects of vent blocking on the smoke yield to the smoker. The reviewed studies fall into four main categories: (1) measurements of the incidence of filter vent blocking among smokers; (2) the observed effects of vent blocking on cigarette ventilation and machine smoke yields; (3) the effect of experimentally blocking vents on human smoke yields; and (4) simultaneous determination of vent blocking and smoke yield under human smoking conditions. Direct observation indicates that only 4% of smokers have their fingers in direct contact with the cigarette during puffing. Estimates of vent blocking incidence by lips during smoking range from 15-24% (saliva-staining technique) to up to 50% ('tar’ staining pattern technique) of smokers. For those smokers who do block the ventilation zone, a mean of 27% of the vents are blocked, and a maximum of about 50%. When the cigarettes are machine-smoked, the smoke yield increases in a highly non-linear manner as the blocked portion of the filter ventilation zone increases. This effect is also more pronounced at higher original filter ventilation levels. In contrast, smoking behavior monitoring techniques have shown that when the experimenter deliberately blocks the vent zone, the human smoker adjusts by taking smaller and fewer puffs. The blocked filter affects the yields of smoke components to the smoker less than it does smoking-machine measured yields. It is concluded that the incidence of vent zone blocking by fingers is quite low and relatively insignificant. The most reliable estimate for lip blocking is that up to 25% of smokers may cover the vent zone during at least one puff and for most smokers the coverage is partial. Ventilation zone blocking as it occurs in practice has only a relatively minor effect on human smoke yields compared to other smoker behavior factors. When a human smoker inadvertently partially or completely blocks the filter ventilation zone during smoking, he/she adjusts by taking smaller and fewer puffs. Because of these changes in puffing behavior during human smoking, predictions of the effects of filter vent blocking on smoke yields based solely on smoking machine yields are deceptive.
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Miyazaki, Junichi, Shinsuke Kawagucci, Akiko Makabe, Ayu Takahashi, Kazuya Kitada, Junji Torimoto, Yohei Matsui, et al. "Deepest and hottest hydrothermal activity in the Okinawa Trough: the Yokosuka site at Yaeyama Knoll." Royal Society Open Science 4, no. 12 (December 2017): 171570. http://dx.doi.org/10.1098/rsos.171570.
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Since the initial discovery of hydrothermal vents in 1977, these ‘extreme’ chemosynthetic systems have been a focus of interdisciplinary research. The Okinawa Trough (OT), located in the semi-enclosed East China Sea between the Eurasian continent and the Ryukyu arc, hosts more than 20 known vent sites but all within a relatively narrow depth range (600–1880 m). Depth is a significant factor in determining fluid temperature and chemistry, as well as biological composition. However, due to the narrow depth range of known sites, the actual influence of depth here has been poorly resolved. Here, the Yokosuka site (2190 m), the first OT vent exceeding 2000 m depth is reported. A highly active hydrothermal vent site centred around four active vent chimneys reaching 364°C in temperature, it is the hottest in the OT. Notable Cl depletion (130 mM) and both high H 2 and CH 4 concentrations (approx. 10 mM) probably result from subcritical phase separation and thermal decomposition of sedimentary organic matter. Microbiota and fauna were generally similar to other sites in the OT, although with some different characteristics. In terms of microbiota, the H 2 -rich vent fluids in Neuschwanstein chimney resulted in the dominance of hydrogenotrophic chemolithoautotrophs such as Thioreductor and Desulfobacterium . For fauna, the dominance of the deep-sea mussel Bathymodiolus aduloides is surprising given other nearby vent sites are usually dominated by B. platifrons and/or B. japonicus , and a sponge field in the periphery dominated by Poecilosclerida is unusual for OT vents. Our insights from the Yokosuka site implies that although the distribution of animal species may be linked to depth, the constraint is perhaps not water pressure and resulting chemical properties of the vent fluid but instead physical properties of the surrounding seawater. The potential significance of these preliminary results and prospect for future research on this unique site are discussed.
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Chen, Chong, Hiromi Kayama Watanabe, Junichi Miyazaki, and Shinsuke Kawagucci. "Unanticipated discovery of two rare gastropod molluscs from recently located hydrothermally influenced areas in the Okinawa Trough." PeerJ 5 (December 1, 2017): e4121. http://dx.doi.org/10.7717/peerj.4121.
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BackgroundThe deep-sea hydrothermal vent is one of the most ‘extreme’ environments in the marine realm. Few species are capable of inhabiting such ecosystems, despite extremely high productivity there supported by microbial chemosynthesis, leading to high biomass and low species richness. Although gastropod molluscs are one of the main constituents of megafaunal communities at vent ecosystems, most species belong to several typical families (e.g., Provannidae, Peltospiridae, Lepetodrilidae) specialised and adapted to life at vents.MethodsDuring recent surveys of Okinawa Trough hydrothermal vent systems, two snails atypical of vent ecosystems were unexpectedly found in newly discovered hydrothermally influenced areas. Shell and radular characteristics were used to identify the gastropods morphologically.ResultsOne species was a vetigastropod, the calliostomatidTristichotrochus ikukoae(Sakurai, 1994); and the other was a caenogastropod, the muricidAbyssotrophon soyoae(Okutani, 1959). Both gastropods were previously only known from regular non-chemosynthetic deep-sea and very rare—only two definitive published records exist forT. ikukoaeand three forA. soyoae. The radula formula ofTristichotrochus ikukoaeis accurately reported for the first time and based on that it is returned to genusOtukaia. For both species, barcode sequences of the cytochromecoxidase I (COI) gene were obtained and deposited for future references.DiscussionThese new records represent the second record of calliostomatids from vents (third from chemosynthetic ecosystems) and the third record of muricids from vents (tenth from chemosynthetic ecosystems), and extend the distribution of both species to the southwest. Neither family has been recorded at chemosynthetic ecosystems in the western Pacific. Both were from weakly diffuse flow areas not subject to high temperature venting but were nevertheless associated with typical vent-reliant taxa such asLamellibrachiatubeworms andBathymodiolusmussels. These new records show that these species are capable of tolerating environmental stress associated with weak hydrothermally influenced areas, despite not being vent endemic species, adding to the list of known vent/non-vent species intersections. This signifies that such weakly influenced areas may provide key habitats for them, and that such areas may play a role in the evolution of biological adaptations to ‘extreme’ chemosynthetic ecosystems.
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Tyler, P. A., and C. M. Young. "Reproduction and dispersal at vents and cold seeps." Journal of the Marine Biological Association of the United Kingdom 79, no. 2 (April 1999): 193–208. http://dx.doi.org/10.1017/s0025315499000235.
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Reproductive cycles are determined from samples taken at regular intervals over a period of time related to the assumed periodicity of the breeding cycle. Fiscal, ship time and sampling constraints have made this almost impossible at deep-sea vents and seeps, but there is an accumulating mass of data that cast light on these processes. It is becoming apparent that most reproductive processes are phylogenetically conservative, even in extreme vent and seep habitats. Reproductive patterns of species occurring at vents and seeps are not dissimilar to those of species from the same phyla found in non-chemosynthetic environments. The demographic structure of most vent and seep animals is undescribed and the maximum ages and growth rates are not known. We know little about how the gametogenic cycle is initiated, though there is a growing body of data on the size at first reproduction. Gametogenic biology has been described from seasonal samples for only one organism from vent/seep environments. For other species, the pattern of gametogenesis has been described from serendipitous samples that allow determination of reproductive effort, but such samples reveal little about energy partitioning during the gametogenic process. Some notable adaptations have been described in mature gametes, including modified sperm. Spawning has been observed for a number of species both in situ and in vitro. Knowledge of the larvae of vent/seep organisms has been derived from laboratory fertilizations, from field collections over vent and seep areas and, for molluscs, from protoconch or prodissoconch size and shape. Larval dispersal has been perhaps the most intractable aspect of reproduction. Because the length of larval life is known for only a single seep organism and no vent organism, we cannot infer dispersal distance from a knowledge of current velocities. Modelling has been used to assess the maximum larval distance that allows effective migration between vent sectors. An indirect approach has been to estimate gene flow within, and between, vent sites using DNA sequencing and electrophoretic techniques. Although data are still equivocal, there are indications of considerable mixing among populations within and between vent sectors of the same ridge. Our knowledge of reproductive biology in vent and seep organisms remains fragmentary, but with molecular and biochemical techniques, emerging larval culture techniques, and increased sampling effort, the pieces of the jigsaw will eventually form an overall picture.
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Cooper, L. Y. "Combined Buoyancy and Pressure-Driven Flow Through a Shallow, Horizontal, Circular Vent." Journal of Heat Transfer 117, no. 3 (August 1, 1995): 659–67. http://dx.doi.org/10.1115/1.2822627.
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Combined buoyancy and pressure-driven (i.e., forced) flow through a horizontal vent is considered where the vent-connected spaces are filled with fluids of different density in an unstable configuration (density of the top is larger than that of the bottom). With zero-to-moderate cross-vent pressure difference, Δp, the instability leads to bidirectional exchange flow between the two spaces, e.g., as in the emptying from the bottom of a liquid-filled can with a single vent opening. For relatively large Δp, the flow through the vent is unidirectional, from the high to the low-pressure space, e.g., as is the case when the can has a large enough second vent at the top. Problems of a commonly used unidirectional orifice vent flow model, with Bernoulli’s equation and a constant flow coefficient, CD are discussed. First, the orifice model does not predict bidirectional flows at zero-to-moderate Δp. Also, when Δp exceeds the critical value, ΔpFL, which defines the onset of unidirectional or “flooding” flow, there is a significant dependence of CD on the relative buoyancy of the upper and lower fluids (i.e., CD is not constant). Analysis of relevant boundary value problems and of available experimental data leads to a mathematical vent flow model, which removes the problems of the orifice flow model. The result is a general algorithm to calculate flow through shallow, horizontal, circular vents under high-Grashof-number conditions.
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Kim, Yun Young, and Chi Young Lee. "Numerical Simulation of the Effects of Compartment Height, Fire Source Location, and Vent Location on Compartment Fire Phenomena with a Ceiling Vent." Fire Science and Engineering 38, no. 5 (October 31, 2024): 1–7. http://dx.doi.org/10.7731/kifse.bcec8f26.
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In this study, the numerical simulations of the effects of compartment height, fire source location, and vent location on the compartment fire phenomena with a ceiling vent were performed. Under the same fire source and vent location conditions, the compartment height of 5.5 m showed a higher mass flow rate across the vent than that of 11 m. For the fire source at the center, the vent on the left showed a lower mass flow rate than that at the center for both compartment heights. For the fire source on the left, the vents on the right and left exhibited the lowest mass flow rates at the compartment heights of 5.5 m and 11 m, respectively. Moreover, for the fire source on the left, a macroscopic rotational flow in the clockwise direction was observed at the compartment height of 5.5 m, whereas at the compartment height of 11 m, macroscopic rotational flows in the clockwise and counterclockwise directions appeared at its lower and upper portions, respectively. It was confirmed that these macroscopic rotational flows were closely related to the change in the mass flow rate across the vent with the vent location. The compartment height of 11 m had a lower average temperature inside the compartment than that of 5.5 m, which was because of the increase in the surrounding wall area. In addition, under each compartment height condition, the changes in the average temperature inside the compartment with the fire source and vent locations were minor.
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Bianchi, C. Nike, and Carla Morri. "Serpuloidea (Annelida: Polychaeta) from Milos, an island in the Aegean Sea with submarine hydrothermalism." Journal of the Marine Biological Association of the United Kingdom 80, no. 2 (April 2000): 259–69. http://dx.doi.org/10.1017/s0025315400001831.
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Serpuloidea were collected by diving within 45 m depth, by indirect sampling in deeper waters (50 and 81 m), and among the fouling settled on oceanographic instruments at various depths (10, 50, 80 and 83 m depth). A total of 33 species or subspecific taxa was found: 25 Serpulidae and eight Spirorbidae. All the species collected are already known for the western Mediterranean and have Atlantic–Mediterranean or worldwide distribution. Several of these, however, may be species-complexes hiding species with restricted geographic ranges. No Lessepsian migrants were found. The number of species found at vent sites was significantly higher than that found at non-vent sites, although no vent-obligate species were recognized. Hydrothermal vents might influence serpuloidean richness through four main mechanisms: (i) increasing food sources to these filter-feeders, due to the chemiosynthetic production by vent microbiota; (ii) enhancing the development of biogenic carbonate mounds, which provide habitats for encrusting and cryptic species; (iii) inducing advective mechanisms that concentrate larval stages in the vicinity of vents and thus favouring recruitment; (iv) creating, through the periodic emission of toxic fluids, a regime of `intermediate disturbance' that allows a larger number of species to coexist.
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Smith, Brendan, and David R. Barclay. "The soundscape of two deep-sea hydrothermal vent sites." Journal of the Acoustical Society of America 152, no. 4 (October 2022): A212. http://dx.doi.org/10.1121/10.0016042.
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Hydrothermal vents are sea floor structures where geothermally heated seawater is discharged. The high-temperature, chemically rich environment is host to uniquely adapted marine life. Vent soundscapes may contain important bioacoustic cues as well as signals enabling passive acoustic monitoring of hydrothermal vent dynamics. Proposals for deep-sea mining of seafloor massive sulfides near hydrothermal vents have elicited concern over potential environmental impacts due to disturbance from industrial activity, including changes to the soundscape. This study assesses the baseline soundscape at two sites, the Main Endeavour Field on the Juan de Fuca Ridge and the Lucky Strike vent field on the Mid-Atlantic Ridge over 12 months and 3 months respectively. To facilitate comparison with future studies at other sites, the most recently proposed standard soundscape analysis methodologies are employed, including terminology in alignment with ISO 18405:2017. In accordance with the latest soundscape standard literature, metrics quantifying the amplitude, impulsiveness, periodicity, and uniformity are reported. Spectral probability densities, percentiles, and long-term spectrograms are computed in hybrid millidecade frequency bands. Finally, a qualitative analysis is included to describe the source types contributing to the hydrothermal vent sound field.
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Portail, M., K. Olu, E. Escobar-Briones, J. C. Caprais, L. Menot, M. Waeles, P. Cruaud, P. M. Sarradin, A. Godfroy, and J. Sarrazin. "Comparative study of vent and seep macrofaunal communities in the Guaymas Basin." Biogeosciences 12, no. 18 (September 21, 2015): 5455–79. http://dx.doi.org/10.5194/bg-12-5455-2015.
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Abstract. 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.
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Rivalta, E., F. Corbi, L. Passarelli, V. Acocella, T. Davis, and M. A. Di Vito. "Stress inversions to forecast magma pathways and eruptive vent location." Science Advances 5, no. 7 (July 2019): eaau9784. http://dx.doi.org/10.1126/sciadv.aau9784.
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When a batch of magma reaches Earth’s surface, it forms a vent from which volcanic products are erupted. At many volcanoes, successive batches may open vents far away from previous ones, resulting in scattered, sometimes seemingly random spatial distributions. This exposes vast areas to volcanic hazards and makes forecasting difficult. Here, we show that magma pathways and thus future vent locations may be forecast by combining the physics of magma transport with a Monte Carlo inversion scheme for the volcano stress history. We validate our approach on a densely populated active volcanic field, Campi Flegrei (Italy), where we forecast future vents on an onshore semiannular belt located between 2.3 and 4.2 km from the caldera center. Our approach offers a mechanical explanation for the vent migration over time at Campi Flegrei and at many calderas worldwide and may be applicable to volcanoes of any type.
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Mehta, Mausmi P., David A. Butterfield, and John A. Baross. "Phylogenetic Diversity of Nitrogenase (nifH) Genes in Deep-Sea and Hydrothermal Vent Environments of the Juan de Fuca Ridge." Applied and Environmental Microbiology 69, no. 2 (February 2003): 960–70. http://dx.doi.org/10.1128/aem.69.2.960-970.2003.
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ABSTRACT The subseafloor microbial habitat associated with typical unsedimented mid-ocean-ridge hydrothermal vent ecosystems may be limited by the availability of fixed nitrogen, inferred by the low ammonium and nitrate concentrations measured in diffuse hydrothermal fluid. Dissolved N2 gas, the largest reservoir of nitrogen in the ocean, is abundant in deep-sea and hydrothermal vent fluid. In order to test the hypothesis that biological nitrogen fixation plays an important role in nitrogen cycling in the subseafloor associated with unsedimented hydrothermal vents, degenerate PCR primers were designed to amplify the nitrogenase iron protein gene nifH from hydrothermal vent fluid. A total of 120 nifH sequences were obtained from four samples: a nitrogen-poor diffuse vent named marker 33 on Axial Volcano, sampled twice over a period of 1 year as its temperature decreased; a nitrogen-rich diffuse vent near Puffer on Endeavour Segment; and deep seawater with no detectable hydrothermal plume signal. Subseafloor nifH genes from marker 33 and Puffer are related to anaerobic clostridia and sulfate reducers. Other nifH genes unique to the vent samples include proteobacteria and divergent Archaea. All of the nifH genes from the deep-seawater sample are most closely related to the thermophilic, anaerobic archaeon Methanococcus thermolithotrophicus (77 to 83% amino acid similarity). These results provide the first genetic evidence of potential nitrogen fixers in hydrothermal vent environments and indicate that at least two sources contribute to the diverse assemblage of nifH genes detected in hydrothermal vent fluid: nifH genes from an anaerobic, hot subseafloor and nifH genes from cold, oxygenated deep seawater.
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Leyte, Jerry C., and Charles F. Forney. "Optimizing Flat Design for Forced-air Cooling of Blueberries Packaged in Plastic Clamshells." HortTechnology 9, no. 2 (January 1999): 202–5. http://dx.doi.org/10.21273/horttech.9.2.202.
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Forced-air cooling rates of highbush blueberries (Vaccinium corymbosum L.) packaged in 6-oz (177-mL) or 1-pt (473-mL) clamshell containers were affected by positions of vent holes in corrugated flats. Most rapid cooling occurred in flats with vents across the top of the flat. Additional vents aligned in front of clamshells resulted in more rapid and uniform cooling than vents placed between clamshells. Vent holes in the bottom of flats had no effect on cooling rates. Clamshells cooled more slowly in the front of the pallet where cold air entered than in the back of the pallet where cold air exited. Fruit in 6-oz clamshells cooled faster than fruit in 1-pt clamshells.
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Kiessling, Jürgen, Barbara Brenner, Charlotte Thunberg Jespersen, Jennifer Groth, and Ole Dyrlund Jensen. "Occlusion Effect of Earmolds with Different Venting Systems." Journal of the American Academy of Audiology 16, no. 04 (April 2005): 237–49. http://dx.doi.org/10.3766/jaaa.16.4.5.
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In this study the occlusion effect was quantified for five types of earmolds with different venting. Nine normal-hearing listeners and ten experienced hearing aid users were provided with conventional earmolds with 1.6 and 2.4 mm circular venting, shell type earmolds with a novel vent design with equivalent cross-sectional vent areas, and nonoccluding soft silicone eartips of a commercial hearing instrument. For all venting systems, the occlusion effect was measured using a probe microphone system and subjectively rated in test and retest sessions. The results for both normal-hearing subjects and hearing aid users showed that the novel vents caused significantly less occlusion than the traditional vents. Occlusion effect associated with the soft silicone eartip was comparable to the nonoccluded ear. Test-retest reproducibility was higher for the subjective occlusion rating than for the objectively measured occlusion. Perceived occlusion revealed a closer relationship to measured occlusion in the ear in which the measured occlusion effect was higher ("high OE" ear) than in the "low OE" ear. As our results suggest that subjective judgment of occlusion is directly related to the acoustic mass of the air column in the vent, the amount of perceived occlusion may be predicted by the vent dimensions.
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Solefack Dongmo, Parick Mao, Julius Kewir Tangka, and Boris Merlain Djousse. "Caractérisation des vents induits par les véhicules en mouvement et évaluation de leur potentiel éolien." Journal of Renewable Energies 22, no. 2 (October 6, 2023): 257–68. http://dx.doi.org/10.54966/jreen.v22i2.743.
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Cette étude a été menée au Cameroun dans le département de la Menoua, région de l’Ouest avec pour objectif une meilleure connaissance des vents induits par les véhicules en mouvement, ainsi que leurs potentiels énergétiques. Pour y parvenir, des données ont été collectées avec un anémomètre monté sur un véhicule, puis elles ont été analysées à l’aide de Microsoft Excel et du Logiciel SPSS 23. L’étude s’est intéressée à la variation de la vitesse du vent en fonction de celle du véhicule, de la position du capteur de l’anémomètre au tour du véhicule et ainsi que de l’altitude. Elle a révélé à son terme que, le vent induit par les véhicules en mouvement est un vent artificiel caractérisé par sa direction qui est unique et qui est toujours opposé au sens d’avancement du véhicule, sa vitesse qui dépend de la vitesse d’avancement du véhicule, qui varie tout autour de celui-ci (avec les positions avant et dessus présentant des avantages relatifs par rapport aux positions derrière et latérale basse) et qui est indépendante de l’altitude. Par rapport aux vents naturels, il présente l’avantage d’être plus stable et facile à prédire. Ce vent recèle également une immense quantité d’énergie dont la valorisation permettrait de développer plusieurs applications notamment dans le domaine de l’énergie des transports.
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Kuk, Francis, Denise Keenan, Chi-Chuen Lau, Nick Dinulescu, Richard Cortez, and Patricia Keogh. "Real-World Performance of a Reverse-Horn Vent." Journal of the American Academy of Audiology 16, no. 09 (October 2005): 653–61. http://dx.doi.org/10.3766/jaaa.16.9.3.
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The present study compared differences in subjective and objective performance in completely-in-the-canal (CIC) hearing aids with conventional uniform 1.5 mm parallel vents and another with a reverse horn vent where the diameter increased from 1.5 mm on the lateral faceplate to 3 mm on the medial opening of the hearing aid. Nine hearing-impaired persons with a high-frequency hearing loss participated. The test battery included unaided in situ thresholds, amount of available gain before feedback, speech in quiet, speech in noise (HINT), subjective ratings of hollowness and tolerance, objective measures of the occlusion effect, and real-ear aided response. Results showed less available gain before feedback but less occlusion effect for subjective ratings and objective measures with the reverse horn vent. This type of vent design may be useful to increase the effective vent diameter of custom (including CIC) hearing aids.
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Chen, Ching-Mei, Yi-Pin Lin, Sung-Chin Chung, and Chi-Ming Lai. "Effects of the Design Parameters of Ridge Vents on Induced Buoyancy-Driven Ventilation." Buildings 12, no. 2 (January 24, 2022): 112. http://dx.doi.org/10.3390/buildings12020112.
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With ridge vents that are commonly used in building ventilation applications as the research object, this study analyzed how design parameters affect the efficiency of thermal buoyancy-driven ventilation induced by ridge vents through computational fluid dynamics (CFD). The design parameters of ridge vents include the width S, height H, and eave overhang E. In consideration of engineering practices, the parameter ranges were set as follows: S = 1.2, 1.8, 2.4, and 3 m; H = 0.3, 0.6, 0.9, and 1.2 m; and E = 0, 0.3, and 0.6 m. The results show that when a ridge vent is under buoyancy-driven ventilation, the height H serves as the dominant design parameter. Correlation equations of the induced ventilation rates with the relevant ridge vent design parameters are provided.
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Portail, M., K. Olu, E. Escobar-Briones, J. C. Caprais, L. Menot, M. Waeles, P. Cruaud, P. M. Sarradin, A. Godfroy, and J. Sarrazin. "Comparative study of vent and seep macrofaunal communities in the Guaymas Basin." Biogeosciences Discussions 12, no. 11 (June 10, 2015): 8497–571. http://dx.doi.org/10.5194/bgd-12-8497-2015.
Full textAbstract:
Abstract. 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.
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Voight, Janet R. "Meristic variation in males of the hydrothermal vent octopus,Muusoctopus hydrothermalis(Cephalopoda: Octopodidae)." Journal of the Marine Biological Association of the United Kingdom 92, no. 2 (July 22, 2011): 361–66. http://dx.doi.org/10.1017/s0025315411000993.
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Intraspecific variation in characters such as arm sucker and gill lamellae counts in octopodids is yet to be thoroughly investigated, potentially hampering our ability to recognize species. In this study, data from 13 specimens ofMuusoctopus hydrothermaliscollected at four hydrothermal vents on the East Pacific Rise between 8°38′N and 12°48′N are considered. Although the northern and southern octopuses differ minimally in size, mean sucker count by arm in the northern group is 11.7 to 22.8% higher than it is in the southern group; in addition these octopuses typically have an additional gill lamella and bulkier funnel organs. The arms of each individual carry a different number of suckers. The difference is significant on nonadjacent arms, a pattern that merits examination in a broader taxonomic context. Why these differences exist among conspecifics remains unknown, the incidence of parasitic copepods is not different between the groups and the between-group variation in arm suckers seen here compares well with a previous report of variation among 18 specimens from the type locality. Increases in meristic characters (counts) in fish are attributed to lower temperatures during embryonic development following Jordan's rule. Northern and southern vents offer the octopuses a wide temperature range, but vent fluid chemistry differs. Northern vent fluids may be more toxic; if so, developing octopus embryos may survive only minimal vent fluid exposure and therefore develop at low temperatures. At the less toxic southern vents, eggs may survive greater exposure to vent fluids and thus develop at higher temperatures.
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Klyuvitkin, Alexey A., Marina D. Kravchishina, Dina P. Starodymova, Anton V. Bulokhov, and Alla Yu Lein. "Sinking Particle Fluxes at the Jan Mayen Hydrothermal Vent Field Area from Short-Term Sediment Traps." Journal of Marine Science and Engineering 12, no. 12 (December 20, 2024): 2339. https://doi.org/10.3390/jmse12122339.
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The mixing of hydrothermal vent fluids with deep ocean water and near-vent pelagic matter results in particle populations with a complex composition consisting of hydrothermally derived, rock-forming, and biogenic particles. This study is the first investigation of deep sediment trap material collected at the Jan Mayen hydrothermal vent field area at 71° N and 6° W of the southernmost Mohns Ridge in the Norwegian–Greenland Sea. This area is characterized by high magmatic activity, axial volcanic ridges, and mafic-hosted volcanogenic massive sulfide deposits. Data on sinking particle fluxes from two hydrothermal settings, the Troll Wall and Soria Moria vent fields, located about 4 km apart, are discussed in the article. In particular, the study emphasize the differences between two hydrothermal settings from each other that demonstrate the geodiversity of hydrothermal processes within the relatively shallow Jan Mayen hydrothermal vent field area affected by the Iceland and Jan Mayen hotspots. The fluxes of sinking hydrothermally derived particles (barite, gypsum, non-crystalline Fe-Si oxyhydroxides, and Fe, Zn, and Cu sulfides) obtained at the Jan Mayen hydrothermal vents made it possible to elucidate the characteristic features of their buoyancy plumes and compare them with similar data reported for other submarine hydrothermal systems. In terms of the composition of the deep-sea hydrothermal particles from buoyant plumes, the studied vent fields are most similar to the Menez Gwen and Lucky Strike vent fields affected by the Azores hotspot. The supply of hydrothermally derived matter is accompanied by normal pelagic/hemipelagic sedimentation, which is dominated by biogenic particles, especially in the upper water layers.
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DAHLHOFF, ELIZABETH, and GEORGE N. SOMERO. "Pressure and Temperature Adaptation of Cytosolic Malate Dehydrogenases of Shallowand Deep-Living Marine Invertebrates: Evidence for High Body Temperatures in Hydrothermal Vent Animals." Journal of Experimental Biology 159, no. 1 (September 1, 1991): 473–87. http://dx.doi.org/10.1242/jeb.159.1.473.
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Effects of temperature and hydrostatic pressure were measured on cytosolic malate dehydrogenases (cMDHs) from muscle tissue of a variety of shallow- and deep-living benthic marine invertebrates, including seven species endemic to the deep-sea hydrothermal vents. The apparent Michaelis-Menten constant (Km) of coenzyme (nicotinamide adenine dinucleotide, NADH), used to index temperature and pressure effects, was conserved within a narrow range (approximately 15–25 μmoll−1) at physiological temperatures and pressures for all species. However, at elevated pressures, the Km of NADH rose sharply for cMDHs of shallow species (depths of occurrence >Approximately 500 m), but not for the cMDHs of deep-sea species. Cytosolic MDHs of invertebrates from the deep-sea hydrothermal vents generally were not perturbed by elevated temperatures (15–25°C) at in situ pressures, but cMDHs of cold-adapted deep-sea species were. At a single measurement temperature, the Km of NADH for cMDHs from invertebrates from habitats with well-characterized temperatures was inversely related to maximal sustained body temperature. This correlation was used to predict the maximal sustained body temperatures of vent invertebrates for which maximal habitat and body temperatures are difficult to estimate. Species occurring on the ‘smoker chimneys’, which emit waters with temperatures up to 380°C, are predicted to have sustained body temperatures that are approximately 20–25°C higher than vent species living in cooler vent microhabitats. We conclude that, just as adaptation of enzymes to elevated pressures is important in establishing species’ depth distribution patterns, adaptation of pressure-adapted enzymes to temperature is critical in enabling certain vent species to exploit warm-water microhabitats in the vent environment.