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The article in the journal "Frontiers in Earth Science" explores contemporary studies on cold seeps, hydrothermal vents, mud volcanoes, and related seafloor features. These features provide insights into deep processes that are typically inaccessible to scientists. The research emphasizes multidisciplinary approaches to studying seafloor fluid emissions, highlighting the importance of geologic, physical, chemical, and biological processes in these environments. The studies cover a wide range of topics, including microbial processes, fluid dynamics, mineralization, and the role of seafloor emissions in global biogeochemical cycles. [Extracted from the article]

With the development of the petrochemical industry, the number of storage tanks has continuously increased, exacerbating the issue of oil evaporation losses. Therefore, it is urgent to find efficient and economical measures to reduce oil evaporation losses. This paper establishes a diffusion model for internal floating roof tanks (IFRTs) and uses numerical simulation methods to study the mass fraction distribution, pressure distribution, and the variation patterns of oil vapor inside the tanks at different floating roof heights. The results show that the closer to the top of the tank, the lower the oil vapor mass fraction, and the mass fraction distribution is almost symmetrical. As the floating roof height decreases, the vapor mass fraction in the mixed gas region inside the tank gradually decreases, showing a distribution below the lower explosive limit (LEL), indicating improved safety. Furthermore, the study found that in the benchmark model, the behavior characteristics of gasoline vapor are reflected in the changes in mass fraction, velocity, and pressure distribution, where the oil vapor concentration in the upper part is lower but evenly distributed. By comparing the behavior characteristics of oil vapor inside the tank at different floating roof heights, it was found that the floating roof height significantly affects the diffusion and accumulation of oil vapor. The presence of vents effectively reduces the accumulation of oil vapor concentration, improving the stability and safety inside the tank. For different floating roof height scenarios (such as CASE 1, CASE 2, and CASE 4), the oil vapor behavior characteristics are similar. The study results provide important theoretical support for the future development of oil vapor recovery technologies and the design of enclosed energy-saving recovery devices inside tanks, indicating that optimizing the floating roof height and vent system design can significantly reduce oil evaporation losses. [ABSTRACT FROM AUTHOR]

The article features the dimensions applied by ancient figure casters. It summarizes the findings of eye molding forms for spearheads and axe blades from the Ob-Irtysh interfluve. The initial reference point for marking the negative tip of the spearhead was the toe length, which determined the bushing length as 2 to 1. After removing the contours of the bushing, the master marked the maximum width of the toe on the negative of the casting mold. The conditional points were in the middle of the spearhead length. The central rib (stiffening rib) corresponded to the length of the toe, and the endings of the parallel lateral ribs (teeth) fell on the maximum expansion of the toe. The upper edge of the eye and the upper line of the belt were marked at a distance equal to the outer diameter of the bushing towards the blade. The reconstructed system of relations between the whole and its parts could be defined as the dimensional standard observed by the master. The hook under the toe gave it the necessary structural strength. It prevented the toe from sinking, and the fracture did not load along the line of connection between the toe and the bushing. The new dimensional standard occurred as the position of the fork in the spearhead design changed. The Seima-Turbino axes also had a 2 to 1 ratio. Initially, the edge of the eye was marked at a distance equal to half the length of the vent of the bushing. Then, the eye was designed in the vent direction. In Samus-Kizhirovo moldings, the eye was modeled not in the direction of the vent of the bushing, but in the opposite one, i.e., to the blade. The single-eye design was original, and the two-eye products appeared as a result of its modification that made it possible to spearheads and axes with solid eyes.

Explosive submarine arc volcanoes can cause tsunamis, affect climate, and pose hazards to airplanes and ships. Although 70 % of the Earth is submarine, only 15 % of Holocene arc volcanoes in the Smithsonian Global Volcanism database are submarine. Merging locations of active submarine hydrothermal vents in arcs and the above database, we found 71 unlisted submarine arc volcanoes. Using Baker [2017, doi: 10.1016/j.oregeorev.2017.02.006], only 44 % of hydrothermal vents in arcs are known. Only 77 of the vent fields are on volcanoes in the Smithsonian database. Assuming that unknown submarine arc volcanoes are present in the same proportions as unknown vents, there are ~160 as-yet undiscovered Holocene age submarine arc volcanoes. Using geophysical data, we located 291 unsurveyed seamounts 32 % of Holocene arc volcanoes are submarine.

The early Iron Age pottery kiln excavated at Groß Kienitz (Brandenburg) in 2017 still contained in situ remains of former firing loads. The finds consist of collapsed yet entirely preserved misfired vessels and numerous potsherds that have been secondarily used as firing aids or as technological fill of the firing chamber. Since the vessel shape types deriving from this closed find can be attributed to both the late Bronze Age as well as the early Iron Age, showing clear elements of the regional Göritz group, the strict division between the two periods is questioned once more. Some constructive elements of the domed clay-lined kiln such as a re-usable vent lid made from a pot remain so far unparalleled. Such details indicate an experimental phase arising from new demands requiring a reducing firing atmosphere to produce dark vessel surfaces. At the same time, kiln construction has to be viewed as the result of a changed self-perception of artisans as much as during antiquity the usage of fire is set against a mytho-practical background. Ancient sources, among them the poem 'The Kiln' attributed to Homer, stress that after closing the kiln (reduction phase) the firing process happens without further human intervention. In ancient beliefs, without proper super-natural assistance this critical phase could result in misfiring and the destruction of the kiln. [ABSTRACT FROM AUTHOR]

With the development of the petrochemical industry, the number of storage tanks has continuously increased, exacerbating the issue of oil evaporation losses. Therefore, it is urgent to find efficient and economical measures to reduce oil evaporation losses. This paper establishes a diffusion model for internal floating roof tanks (IFRTs) and uses numerical simulation methods to study the mass fraction distribution, pressure distribution, and the variation patterns of oil vapor inside the tanks at different floating roof heights. The results show that the closer to the top of the tank, the lower the oil vapor mass fraction, and the mass fraction distribution is almost symmetrical. As the floating roof height decreases, the vapor mass fraction in the mixed gas region inside the tank gradually decreases, showing a distribution below the lower explosive limit (LEL), indicating improved safety. Furthermore, the study found that in the benchmark model, the behavior characteristics of gasoline vapor are reflected in the changes in mass fraction, velocity, and pressure distribution, where the oil vapor concentration in the upper part is lower but evenly distributed. By comparing the behavior characteristics of oil vapor inside the tank at different floating roof heights, it was found that the floating roof height significantly affects the diffusion and accumulation of oil vapor. The presence of vents effectively reduces the accumulation of oil vapor concentration, improving the stability and safety inside the tank. For different floating roof height scenarios (such as CASE 1, CASE 2, and CASE 4), the oil vapor behavior characteristics are similar. The study results provide important theoretical support for the future development of oil vapor recovery technologies and the design of enclosed energy-saving recovery devices inside tanks, indicating that optimizing the floating roof height and vent system design can significantly reduce oil evaporation losses.

Introduction: Patients with chronic renal disease (CKD) are at a significantly elevated risk for ventricular arrhythmia. Several electrocardiographic (ECG) methods can be used to assess the ventricular arrhythmia risk on the standard 12-lead ECG.Aim: This study aimed to evaluate the ECG parameters of ventricular repolarization abnormalities, such as QT, QTc, Tp-e, and Tp-e/QT ratio, Tp-e/QTc ratio, and their predictors in hemodialytic end-stage renal disease (ESRD) patients.Materials and methods: Fifty-three patients with hemodialytic ESRD and 32 pre-dialytic CKD patients were enrolled in the study. ECG parameters were measured manually using calipers. The independent samples t-test was used for comparative analysis. The multivariate linear regression analysis was used to distinguish the independent predictors of each ECG parameters and variables correlating significantly in bivariate analysis.Results: Mean ages of hemodialytics and pre-dialytics were 47±11 and 51±7 years, respectively. Ventricular repolarization abnormalities in the hemodialytic compared to the pre-dialytic group were found to be significantly different [QTc (448±34 vs. 428±31 ms, p=0.007), Tp-e (81±20 vs. 71±19 ms, p=0.025), Tp-e/QT (0.23±0.06 vs. 0.20±0.05, p=0.043)]. QTc interval was positively correlated with sodium (p=0.001) and age (p=0.007). Tp-e/QT ratio was the ECG parameter correlated to most of variables including eGFR (p=0.003), creatinine (p=0.040), potassium (p=0.009), chloride (p=0.048), and glucose (p=0.041).Conclusions: Ventricular repolarization was found to be increased in patients with hemodialytic ESRD. Hence, observation ECG parameters of ventricular repolarization should be performed in the hemodialytic patients for early detection of ventricular arrhythmia.

People have been experiencing more negative affect (NA) during the coronavirus disease 2019 pandemic than prior to its onset. This may increase instances of people venting their emotions and blaming others to relieve the flood of unregulated NA. This study examined individuals' venting and blaming processes within the context of the pandemic and explored the mediating role of emotional clarity across cultures. We conducted an online survey with 210 and 197 participants from the US and South Korea, respectively. The results of the moderated mediation analysis showed that individuals' NA during the pandemic significantly affected their venting and blaming via emotional clarity among US participants. This finding implies that when people in individualistic cultures do not fully understand their emotions, they are more likely to vent to or blame others. This can serve as a potential risk factor for hate crimes during the pandemic. Conversely, the mediation effect of emotional clarity was not significant among South Korean participants, suggesting dissimilar roles played by emotional clarity in individualistic versus collectivistic cultures in managing NA. [ABSTRACT FROM AUTHOR]

Readily available processing hardware and "off-the-shelf" (OTS) simulation software has made "high fidelity" first principles models of both steady and transient states, for both axial and centrifugal industrial compressors, relatively easy to construct. These high-fidelity models are finding their way into "real-time. digital twin" performance monitors, front-end engineering design, and post-design – pre-construction compressor performance evaluation. The compressor models are useful for reliably demonstrating the compressor and – to some degree, based on the complexity of the model – process response to various operating conditions. Once the model is constructed, it is trivial to run a "what-if" analysis of compressor performance to answer questions related to (a) recommendations or validation of the recycle/vent valve size and actuation speed, (b) general piping layout and sizing around the compressor, (c) and hot gas bypass requirements, to name a few. This paper takes a practical approach in discussing the compressor and process parameters necessary for building these dynamic "high-fidelity" industrial-compressor models. We identify compressor inputs and compressor responses that are faithfully modeled by first-principle equations available in the simulation software and those that typically require a compromise between an "ab initio" and data-fitting approximation. We discuss the simulation's tendency to overstate pressure excursions during surge events and understate the compressor operation in the "stonewall" region. We also discuss using the simulator software's compressor-stage enthalpy calculations to predict and quantify the compressor train reverse rotation. We use our broad experience and understanding of the compressor operation and simulation and our experience with the AVEVA™ Dynamic-Simulation "OTS" simulation software as the basis for this discussion.

Explosive volcanic eruptions eject a gas-particle mixture into the atmosphere. The characteristics of this mixture in the near-vent region are a direct consequence of the underlying initial conditions at fragmentation and the geometry of the shallow plumbing system. Yet, it is not possible to observe directly the sub-surface parameters that drive such eruptions. Here, we use scaled shock-tube experiments mimicking volcanic explosions in order to elucidate the effects of a number of initial conditions. As volcanic vents can be expected to possess an irregular geometry, we utilise three vent designs, two "complex" vents and a vent with a "real" volcanic geometry. The defining geometry elements of the "complex" vents are a bilateral symmetry with a slanted top plane. The "real" geometry is based on a photogrammetric 3D model of an active volcanic vent with a steep and a diverging vent side. Particle size and density as well as experimental pressure are varied. Our results reveal a strong influence of the vent geometry, on both the direction and the magnitude of particle spreading and the velocity of particles. The overpressure at the vent herby controls the direction of the asymmetry of the gas-particle jet. These findings have implications for the distribution of volcanic ejecta and resulting areas at risk. [ABSTRACT FROM AUTHOR]

When gas explosion occurs in closed vessel, venting devices can reduce the pressure inside the protected equipment, and vent ducts can be used to direct burnt and unburnt mixtures. In this paper, some ductless and duct vented explosion measurements were performed in a standard 20-liter explosion chamber with 2.8 to 6.3 vol.% propane-air mixture at atmospheric pressure (1 barg) and ambient temperature (298 K). Experimental investigations were performed with different lengths of vent duct (0 meter, 0.15 meter, 1 meter). During the measurements, effects of vent ducts to the venting process had been studied. Aluminium foils were used as rupture disks with 30 mm diameter circular venting area. During each measurement, static activation overpressure of aluminium foil, maximum explosion overpressure of propane-air mixture, the gas deflagration index in case of the vented vessel, and the pressure drop along the 1 meter length duct were determined. [ABSTRACT FROM AUTHOR]

The southeast of the Iberian Peninsula (Spain) is characterized by a significant recurrence of nocturnal temperature inversion processes (ITN), mainly due to the large number of clear days throughout the year. The Segura River Basin District (DHS) has an altitude difference of 2100m in 150km with alternating valley areas and orographically complex and rugged areas. This gives rise to marked night-time thermal contrasts, whose vertical thermal differences are 13.0ºC between cold air pools (CAP) and uneven surfaces. Thermal contrasts are analysed through 58 meteorological observatories in the 50 mornings with the highest intensity of thermal inversion in the last years of observation (2011-2020). Furthermore, the characteristics and triggering causes of such processes are analysed through the analysis of variables influencing the distribution of minimum temperatures (wind, relative humidity, ...). In addition, a high-resolution satellite analysis technique is presented, through the elaboration of thermographies (distribution of surface temperatures) by means of the ASTER sensor, which complement, from the spatial point of view, the distribution of minimum temperatures in the early mornings of ITN in some sectors of the study area. Among the most conclusive results, notable thermal differences stand out during stable early mornings (mean differences of 7.1ºC and absolute differences of 13ºC between observatories located at valley bottoms (CAP) and those located at higher altitudes, in orographically rugged areas), recorded under masses warm and dry air at a geopotential level of 850hPa. [ABSTRACT FROM AUTHOR]

Venting is an essential operation step before starting the centrifugal pump. During the process of venting, the centrifugal pump faces the problems of oil splash, slop oil in the slop tank and excessive loss of crude oil during venting. Through the analysis on the actual production and operation of one oil transportation station in Xinjiang Tarim-Shihezi Pipeline, it is concluded that the main causes of the excessive crude oil loss during venting attribute to the excessively shallow and overlong guide oil tank for draining, and the air bubbles in the vent pipeline. Based on the investigation on venting of centrifugal pumps before pump starting in China and abroad, the following improvement measures were proposed according to the starting steps, precautions and the actual situation of the oil transportation station. The additional three-way funnel can be used to cope with the crude oil loss caused by the excessively shallow and overlong tank. The vent pipeline can be moved from the side of the centrifugal pump to the rear (the moving distance of about 47 cm) and connected with the three-way funnel to avoid crude oil splashing caused by bubbles in the vent pipeline. The practice shows that this method can effectively reduce the loss of crude oil during venting before starting the centrifugal pump, and the single loss of crude oil during venting declines from 79 g to 0. The improvement measures are simple and safe for operation and capable of meeting the actual needs of the site, so they are supposed to provide important practical significance for optimizing and improving the overall performance of the centrifugal pump.

Physicians have a lot to consider when they place a patient on the ventilator. This article reviews the literature and provides the physician with a clear guide to managing the ventilator in the ICU. This manuscript is meant to be a practical guide to managing the ventilator at the patient's bedside.

Breeding at the right time is essential for animals living in seasonal environments to ensure that energy requirements for reproduction, especially the nutritional needs for rearing offspring, coincide with peak food availability. Climate change is likely to cause modifications in the timing of maximum food availability, and organisms living in polar environments where the breeding period is heavily contracted may be particularly affected. Here we used a 26-year dataset to study the phenological response of a pagophilic species, the Snow Petrel (Pagodroma nivea), to climate change and its demographic impact. First, we investigated the trends and relationships between climate variables and hatching dates measured in three neighboring colonies. In a second step, we examined the impact of the hatching date and environmental covariates on the fledging probability. Our results showed that sea ice, a climate-related variable, showed a positive temporal trend. We found that hatching date was delayed when sea ice concentration was greater and local weather conditions were worse (i.e., increase in the number of windy days or the number of snow days). Hatching date had a negative effect on fledging probability, and fledging probability showed a bell-shaped temporal trend. We suggest that Snow Petrels can delay breeding phenology in response to environmental conditions. However, this plasticity may be limited as fledging success decreased with delayed hatching, potentially making the Snow Petrel vulnerable to a mismatch between resource availability and nutritional needs. [ABSTRACT FROM AUTHOR]

Decades of clinical research into pulsed oxygen delivery has shown variable efficacy between users, and across a user's behaviours (sleep, rest, activity). Modern portable oxygen concentrators (POCs) have been shown as effective as other oxygen delivery devices in many circumstances. However, there are concerns that they are not effective during sleep when the breathing is shallow, and at very high respiratory rates as during physical exertion. It can be challenging to examine the determinants of POC efficacy clinically due to the heterogeneity of lung function within oxygen users, the diversity of user behaviour, and measurement issues. Representative bench testing may help identify key determinants of pulsed-oxygen device efficacy. [ABSTRACT FROM AUTHOR]

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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A surgical technique to drain the medullary content during closed femoral nailing by using a Frazier suction tip as a vent is demonstrated. This method is simple, safe and reproducible. The medullary content can be drained outside without surrounding soft tissue contamination and the intramedullary pressure is possibly minimized when femoral canal reaming and nail insertion is performed.

Naturally acidified environments, such as those caused by volcanic CO2 venting, reveal how complex coral reef ecosystems may respond to future ocean acidification conditions. Few of these sites have been described worldwide, and only a single such site is known from the Caribbean. Herein, we have characterized an area of volcanic acidification at Mayreau Island, St. Vincent and the Grenadines. Despite localized CO2 enrichment and gas venting, the surrounding area has high hard and soft coral cover, as well as extensive carbonate frameworks. Twice daily extremes in acidification, in some cases leading to undersaturation of aragonite, are correlated with tidal fluctuations and are likely related to water flow. Corals persisting despite this periodic acidification can provide insights into mechanisms of resilience and the importance of natural pH variability on coral reefs. [ABSTRACT FROM AUTHOR]

The overpressure and flame generated in the explosion of a gas in different regions of a room outside a vent in it were investigated using computational fluid dynamics. The calculation data obtained were compared with the corresponding results of earlier large-scale experiments on this subject, and they show that the smaller the distance from the vent, the larger the oscillations of the indoor overpressure and that the outside region of the vent substantially influences the indoor explosion flow field. It was established that, as the outside-region length increases, the peak indoor overpressure approaches the experimental one, but the amplitude of the overpressure oscillations caused by the Helmholtz and Taylor effects increases substantially in this case. The numerical simulation of the explosion hazard of a ventilated gas in a room seems reasonable in the case where the outside region of a vent is not shorter than the room. [ABSTRACT FROM AUTHOR]

[Display omitted] • Phylogenomic data from six species representing three deep-water patellogastropod families was obtained. • Mitogenome recovers monophyly of eight families in most trees and consistency in the genus-level relationships; phylogenomics recovers a robust family-level topology. • Deep-water families are monophyletic, indicating a single colonisation around the Jurassic. • A lack of significant correlation between genome size and habitat depth. Patellogastropoda, the true limpets, is a major group of gastropods widely distributed in marine habitats from the intertidal to deep sea. Though important for understanding their evolutionary radiation, the phylogenetic relationships among the patellogastropod families have always been challenging to reconstruct, with contradictory results likely due to insufficient sampling. Here, we obtained mitogenomic and phylogenomic data (transcriptomic or genomic) from six species representing the three predominantly deep-water patellogastropod families: Lepetidae, Neolepetopsidae, and Pectinodontidae. By using various phylogenetic methods, we show that mitogenome phylogeny recovers monophyly of eight families in most of the trees, though the relationships among families remain contentious. Meanwhile, a more robust family-level topology consistent with morphology was achieved by phylogenomics. This also reveals that these mainly deep-water families are monophyletic, suggesting a single colonisation of the deep water around the Jurassic. We also found a lack of significant correlation between genome size and habitat depth, despite some deep-water species exhibiting larger genome sizes. Our phylogenomic tree provides a stable phylogenetic backbone for Patellogastropoda that includes seven of the nine recognized families and paves the way for future evolutionary analyses in this major group of molluscs. [ABSTRACT FROM AUTHOR]

We present a loss-of-function study using antisense morpholino (MO) reagents for the organizer-specific gene Goosecoid (Gsc) and the ventral genes Vent1 and Vent2. Unlike in the mouse Gsc is required in Xenopus for mesodermal patterning during gastrulation, causing phenotypes ranging from reduction of head structures-including cyclopia and holoprosencephaly-to expansion of ventral tissues in MO-injected embryos. The overexpression effects of Gsc mRNA require the expression of the BMP antagonist Chordin, a downstream target of Gsc. Combined Vent1 and Vent2 MOs strongly dorsalized the embryo. Unexpectedly, simultaneous depletion of all three genes led to a rescue of almost normal development in a variety of embryological assays. Thus, the phenotypic effects of depleting Gsc or Vent1/2 are caused by the transcriptional upregulation of their opposing counterparts. A principal function of Gsc and Vent1/2 homeobox genes might be to mediate a self-adjusting mechanism that restores the basic body plan when deviations from the norm occur, rather than generating individual cell types. The results may shed light on the molecular mechanisms of genetic redundancy.

Summary This work deals with an experimental and numerical investigation of a fire scenario involving two rooms mechanically ventilated and connected together with a horizontal vent. The objective is to improve the understanding of the physical phenomena and to assess the capability of computational fluid dynamics (CFD) numerical simulations to predict flow field for such a fire scenario. The study is based on a set of large‐scale fire experiments performed in the framework of the OECD PRISME‐2 project in the DIVA multi‐room facility of the Institut de Radioprotection et de Sûreté Nucléaire (IRSN) and of numerical simulations performed with the ISIS CFD code. The fire scenario consists of two rooms, one above the other, mechanically ventilated and connected to each other with a horizontal vent of 1 m2. The fire is a heptane pool fire located in the lower room. The analysis focuses on the coupling between the burning rate, the flow at the vent, and the configuration of the mechanical ventilation. Several regimes of combustion are encountered from well‐ventilated steady fire to under‐ventilated unsteady and oscillatory fire. The results show that the burning rate is controlled by both the mechanical ventilation and the downward flow from the vent. The numerical simulations highlight the specific pattern of the oxygen concentration field induced by the downward flow at the vent. [ABSTRACT FROM AUTHOR]

In the automotive industry, die casting technology is used in the production of many parts in series. Due to increased customer demands and reliability expectations, tightness properties are dominant in aluminium alloy based cast parts. In order to acquire the tightness property, it is necessary to control the gas porosity at the casting structure. High pressure die casting aluminium alloy products generally contain gas porosity in certain sizes and ratios due to gas compression during high speed injection of molten metal into the die cavity. Proper die design and evacuation of air in the die and also optimized process parameters need a very critical precaution to reduce the gas porosity. Today, various venting, valve, and vacuum systems are used to facilitate the evacuation of die air. The use of venting systems in the process increases both product quality and process efficiency. In this study, the performance of 3D venting system and mechanical valve performance in high pressure aluminium alloy (AlSi10Mg) casting process with cold chamber were compared on MAGMASOFT high pressure die casting simulation program. As a result of the experimental studies of the 3D vents system, the gas porosity and machine shutdown times can be significantly reduced. [ABSTRACT FROM AUTHOR]

Sustainable building design requires the application of natural ventilation, which has three prerequisites - a comfortable outdoor air temperature (20-25°C), unpolluted outdoor air and a low-noise environment (under 55 dBA). There are many locations where the first two prerequisites are met, but the environmental noise makes applying natural ventilation challenging. This research developed an auxiliary noise-reducing vent for windows (NRVW) that allows daylight and outdoor air to enter the room while reducing the penetration of outdoor noise. As an auxiliary, the NRVW is intended to be integrated into any (double) glazed windows with a sound transmission class (STC) above 25 dBA. The research used physical model experiments to measure the NRVW's STC and outdoor-indoor transmission class (OITC). Digital model simulation was used to measure the NRVW's ventilation performance. It was found that NRVW has a rating of STC 18 and OITC 16, and it generates indoor air velocity of 0.015-0.086 m/s in the occupants' zone for an outdoor wind speed of 1-5 m/s. Modification of the room interior increases the indoor air velocity to 0.147 m/s. Computer simulation also demonstrated that, with an occupant inside the room, an outdoor air temperature of 25°C and outdoor wind speed of 1-5 m/s maintained the indoor air temperature at 25.309-25.258°C, indicating that the resulting airflow could keep the indoor air temperature low. Although the NRVW was originally developed for warm-humid climate conditions, it is also applicable for other climates if the required outdoor conditions are met. [ABSTRACT FROM AUTHOR]

Though geochemically and microbially well-defined, the phylogeographic data of microbial symbionts in these highly productive vent and seep systems require a closer examination and synthesis. QIIME analysis of 16S rDNA of bacterial associates of major fauna from 1995 to 2015 was thus undertaken to examine phylogeography of their microbial symbionts along with host specificity. While phylotypes were generally unrelated, bivalve Calyptogena exhibited vertical transmission sharing similar symbionts in geographically separated geosystems. Different species of tubeworms possessed identical symbionts through horizontal acquisition at geographically distinct Guaymas basin vent and the Arctic seep. Vents were more versatile with both mobile and sessile fauna hosting ecto- and endo-symbionts. Comparatively, seeps were more specialized with sessile animal hosts with endosymbionts. C-fixation rate measurements are still scanty for sediments, bedrocks and serpentine systems; vent, seep, anoxic and oxic basins were shown to fix up to 22, 325, 96, and 37,400 g C m−3 y−1, respectively. Estimation of chemosynthetic primary production rates in chemoautotrophic ecosystems could endeavor to improve existing biogeographic models by coupling volcanism and plate-tectonics to global climate and phylogeography. [ABSTRACT FROM AUTHOR]

The aim of this study is validation of pressure peaking phenomenon models for unignited and ignited releases of hydrogen in enclosures with limited ventilation, e.g. residential garages. The existence of “unexpected” peak in the pressure transient during release of a lighter than air gas in a vented enclosure was observed by Brennan et al. (2010) by carrying out theoretical and numerical research. The amplitude and duration of this pressure peak vary depending on the enclosure volume, vent size and leak flow rate. The peak can significantly exceed the steady-state overpressure, which is reached when the enclosure is fully occupied by leaking with a constant rate gas. The pressure peaking phenomenon can jeopardise a civil structure integrity in the case of accident if it is ignored at the design stage of hydrogen-powered vehicles. This could cause serious life safety and property protection issues that requires development of prevention and mitigation strategies and innovative safety engineering solutions. The experimental validation of the phenomenon was absent up to this work. The previous model for unignited release and developed in this study model for ignited release (jet fire) have been validated against experiments performed in a vented enclosure of 1 m 3 volume with three different gases: air, helium, and hydrogen. The model for unignited release reproduces closely the experimental pressure peak and the pressure dynamics within the enclosure. The model for ignited release reproduces the pressure peak with acceptable engineering accuracy, and the simulation of pressure dynamics after the peak requires the increase of the discharge coefficient due to the change of vent flow from heavier air at the start to lighter hot combustion products afterwards and ultimately hydrogen. The methodology to calculate the pressure peaking phenomenon in two steps is described in detail. Examples of pressure peaking phenomenon calculation for typical hydrogen applications are presented. The phenomenon is relevant to most of indoor applications, when release of lighter than air gas is possible in an enclosure with limited ventilation. It must be considered when performing safety engineering design of inherently safer hydrogen systems and infrastructure. [ABSTRACT FROM AUTHOR]

The Serra Geral Formation constitutes a continental magmatic province on the southern part of South America within the Paraná basin. Basaltic magmatism of the Serra Geral Formation occurred as extrusions at around 134.5 to 131.5 My ago. The formation is part of the Paraná-Etendeka large igneous province, spanning South America and southwestern Africa. The main extrusion mechanism was probably through fissures related to extensional regime during the breakup of Gondwana in the Cretaceous. Basaltic ring structures (BRS) with tens of meters of diameter, cropping out downstream of Grande river at Água Vermelha hydroelectric dam in southern Triângulo Mineiro region, enable the study of the mechanism of extrusion. The origin of the BRS has been subject to differing interpretations in the past, either collapsed lava flows or central conduits. Detailed geological mapping at 1:1000 scale, stratigraphic, petrographic and gravimetric analysis of the most well preserved of the BRS, with a 200 m diameter, has enabled the description of thirteen different basalt lava flows, along with single a central lava lake and a ring dyke structure. The central flow, interpreted as a preserved lava lake, comprises vesicle- and amygdale-rich basalt, spatter, ropy and degassing structures. The most basal of the thirteen lava flows has massive basalt containing geodes filled with quartz. Above, the lava flows show massive basalt with vertical columnar jointing where is possible to identify the top and bottom of each individual flow, with gentle dips towards the perimeter of the structure. A prominent ring dyke dipping towards the lava lake presents horizontal columnar jointing and cuts the basal and central flows. The gravimetric analysis shows a weak negative Bouguer anomaly on the center of the BRS. The proposed model describes the volcanism of the region in three main steps: (1) fissure flow occurs with lava input; (2) this lava cools and crystallizes cementing most of the fissures, promoting the formation of localized central conduits; and (3) the presence of dissolved gas in lava produces ring and radial fractures around the solidified lava lake. The magma uses some of the ring fissures to ascend and the following lava flows assume the ring shape of the dyke vent. Thus, the BRS in Água Vermelha region can be interpreted as remnants of central conduits representing the late stage magmatism of the Serra Geral Formation. [ABSTRACT FROM AUTHOR]

Abstract: Transient volcanic plumes, having similar eruption duration and rise timescales, characterize many unsteady Strombolian to Vulcanian eruptions. Despite being more common, such plumes are less studied than their steady state counterpart from stronger eruptions. Here we investigate the initial dynamics of transient volcanic plumes using high‐speed (visible light and thermal) and high‐resolution (visible light) videos from Strombolian to Vulcanian eruptions of Stromboli (Italy), Fuego (Guatemala), and Sakurajima (Japan) volcanoes. Physical parameterization of the plumes has been performed by defining their front velocity, velocity field, volume, and apparent surface temperature. We also characterized the ejection of the gas‐pyroclast mixture at the vent, in terms of number, location, duration, and frequency of individual ejection pulses and of time‐resolved mass eruption rate of the ejecta's ash fraction. Front velocity evolves along two distinct trends related to the initial gas‐thrust phase and later buoyant phase. Plumes' velocity field, obtained via optical flow analysis, highlights different features, including initial jets and the formation and/or merging of ring vortexes at different scales. Plume volume increases over time following a power law trend common to all volcanoes and affected by discharge history at the vent. Time‐resolved ash eruption rates range between 102 and 107 kg/s and may vary up to 2 orders of magnitude within the first seconds of eruption. Our results help detailing how the number, location, angle, duration, velocity, and time interval between ejection pulses at the vents crucially control the initial (first tens of second), and possibly later, evolution of transient volcanic plumes. [ABSTRACT FROM AUTHOR]