Evaluating methane outputs from an area of submarine seeps along the northern Hikurangi Margin, New Zealand

<p>Collated global marine surveys have documented large volumes of gaseous methane able to escape from deeply-buried deposits into global oceans as seeps. Seeps are evident where permeable faults and fracture networks allow for the upward transportation of methane from buried deposits into the water column as plumes of rising bubbles. Seep bubbles dissolve the majority of their constitutive methane into the surrounding water column as they rise; however there is evidence of more-prominent seeps transferring undissolved methane through the water column and into the atmosphere. Due to the biologic origins of methane, the global distribution of buried methane de-posits is highly varied and difficult to predict. High uncertainties in seep locations have resulted in all previous estimations of the global proportion of atmospheric methane attributed to seeps to have very large associated errors. These are mainly due to large extrapolations over global oceans based on findings from surveyed seep fields. A 2014 NIWA research voyage saw the discovery of an abundant seep field situated at uncharacteristically shallow water depths (150–300 m below sea level) along the raised continental shelf of the Hikurangi Margin, New Zealand. In comparison to other globally documented seep fields, the Hikurangi Margin seeps are numerous (estimated between 585 and 660 surveyed seeps) and cover a large area (∼ 840 km²). Prior to the discovery of this seep field, there was only evidence of 36 seeps along the entire Hikurangi Margin. Acoustically surveyed bubble-rise paths of newly discovered seeps also show evidence of seeps extending the entire height of the water column. The large number of shallow flares present in the abundant seep field represent the potential for considerable amounts of gaseous methane outputs. To further investigate these seeps, NIWA voyages TAN1505 and TAN1508 that took place in June and July of 2015 employed a range of scientific equipment to analyse features of the rising seep bubbles. Part of these investigations involved the video recordings of rising seep bubbles from the seafloor as well as acoustically surveying rising bubbles using a singlebeam and multibeam echsounder. We have used video and acoustic data sets to create multiple tools and computational techniques for better assessing features of seeps. We have developed photogrammetric tools that can be used in Matlab to compute bubble-size distributions and bubble-rise rates from still frames of underwater video footage. These bubble parameters have then been combined with singlebeam recorded flare profiles to calculate the flux of emitted methane at the seafloor. These calculations were carried out using the FlareFlow Matlab module, devised by Mario Veloso. To assess the number of seeps in a multibeam surveyed region, we have created vertically-summed intensity maps of the obtained water column data. Summed-intensity maps display localised high-amplitude features, indicative of seeps. Seep indicators have been used to (1) map the distribution of seeps of the surveyed Hikurangi Margin, (2) assess the total surveyed seep count, and (3) identify regions where seep concentrations are particularly high. We have combined methane fluxes from analysed seeps with regional seep-distribution maps to approximate the rate at which gaseous methane is escaping from the seafloor across the seep field. Extrapolating seep emissions over the surveyed area approximates 0.99×10⁵ ±0.64×10⁵ m³/yr of undissolved methane is being released across the seep field. Using models of methane preservation, combined with staggered depth models of flares, we have approximated that ∼ 0.2% of the methane emitted at the seafloor is able to reach the atmosphere.</p>

Evaluating methane outputs from an area of submarine seeps along the northern Hikurangi Margin, New Zealand

<p>Collated global marine surveys have documented large volumes of gaseous methane able to escape from deeply-buried deposits into global oceans as seeps. Seeps are evident where permeable faults and fracture networks allow for the upward transportation of methane from buried deposits into the water column as plumes of rising bubbles. Seep bubbles dissolve the majority of their constitutive methane into the surrounding water column as they rise; however there is evidence of more-prominent seeps transferring undissolved methane through the water column and into the atmosphere. Due to the biologic origins of methane, the global distribution of buried methane de-posits is highly varied and difficult to predict. High uncertainties in seep locations have resulted in all previous estimations of the global proportion of atmospheric methane attributed to seeps to have very large associated errors. These are mainly due to large extrapolations over global oceans based on findings from surveyed seep fields. A 2014 NIWA research voyage saw the discovery of an abundant seep field situated at uncharacteristically shallow water depths (150–300 m below sea level) along the raised continental shelf of the Hikurangi Margin, New Zealand. In comparison to other globally documented seep fields, the Hikurangi Margin seeps are numerous (estimated between 585 and 660 surveyed seeps) and cover a large area (∼ 840 km²). Prior to the discovery of this seep field, there was only evidence of 36 seeps along the entire Hikurangi Margin. Acoustically surveyed bubble-rise paths of newly discovered seeps also show evidence of seeps extending the entire height of the water column. The large number of shallow flares present in the abundant seep field represent the potential for considerable amounts of gaseous methane outputs. To further investigate these seeps, NIWA voyages TAN1505 and TAN1508 that took place in June and July of 2015 employed a range of scientific equipment to analyse features of the rising seep bubbles. Part of these investigations involved the video recordings of rising seep bubbles from the seafloor as well as acoustically surveying rising bubbles using a singlebeam and multibeam echsounder. We have used video and acoustic data sets to create multiple tools and computational techniques for better assessing features of seeps. We have developed photogrammetric tools that can be used in Matlab to compute bubble-size distributions and bubble-rise rates from still frames of underwater video footage. These bubble parameters have then been combined with singlebeam recorded flare profiles to calculate the flux of emitted methane at the seafloor. These calculations were carried out using the FlareFlow Matlab module, devised by Mario Veloso. To assess the number of seeps in a multibeam surveyed region, we have created vertically-summed intensity maps of the obtained water column data. Summed-intensity maps display localised high-amplitude features, indicative of seeps. Seep indicators have been used to (1) map the distribution of seeps of the surveyed Hikurangi Margin, (2) assess the total surveyed seep count, and (3) identify regions where seep concentrations are particularly high. We have combined methane fluxes from analysed seeps with regional seep-distribution maps to approximate the rate at which gaseous methane is escaping from the seafloor across the seep field. Extrapolating seep emissions over the surveyed area approximates 0.99×10⁵ ±0.64×10⁵ m³/yr of undissolved methane is being released across the seep field. Using models of methane preservation, combined with staggered depth models of flares, we have approximated that ∼ 0.2% of the methane emitted at the seafloor is able to reach the atmosphere.</p>

DETERMINATION OF THE ASSESSMENT ON INCREASING THE SEISMOSTICITY OF BRICK LAYING OF BUILDINGS AND STRUCTURES WITH DAMAGES AND DEFECTS

The article uses a method of research and determination of damage and defects ofstone structures. This method provides elimination: the presence of cracks, their length, and width ofthe opening, the presence of defects in the brickwork, the presence of erosion in the brickwork, thedisplacement of arched and arched bridges.To assess the strength of bricks and mortar in masonry, the proposed method was as follows.Places for drilling in brickwork were chosen arbitrarily along with the entire height of the masonry.Drilling was performed perpendicular to the brickwork. The number of places required for drillingcorresponded to the number of samples tested for compression, according to the normative document.To determine the performance properties of brickwork, by following per under regulations in acomplete inspection of buildings, sampling methods used a large number of studies. This problem isespecially relevant for brick buildings to the defects and damages of constructive characterestablished during the inspection which accounting by standard methods does not provide necessaryreliability.The task is complicated if the structure, under the influence of certain operational factors, therewas a change in its stress state, which cannot be estimated by calculation. The structural elementselected for inspection is responsible, which in turn will lead to the destruction of the redistributionof forces and will be dangerous, which can lead to the destruction of other elements and the collapseof the entire system of structures. In this situation, it is recommended to adopt a method that allowsyou to experimentally determine the actual level of stress of the whole element or its individual part.The method was developed primarily for old residential and public buildings (architecturalmonuments) and helps to preserve the original appearance of structures, which does not violate thearchitectural ensemble of the whole house.

Combined Reinforced Concrete Columns Strengthening with Steel Clipping and Concrete Surfacing

Постановка задачи. Исследуется метод усиления железобетонных колонн устройством стальной обоймы с обетонированием, который позволяет восстанавливать эксплуатационные показатели колонн, имеющих значительные дефекты и повреждения. Предпосылкой настоящих исследований явилось предположение о том, что усиление стальной обоймой с обетонированием является эффективным способом повышения несущей способности железобетонных колонн, причем вариант приложения нагрузки - только на бетонное ядро или ко всему сечению - существенно на эффективность усиления не влияет. В связи с этим целью исследования является определение необходимости устройства стального оголовка и включения в работу ветвей стальной обоймы при условии обетонирования стержня колонны по всей высоте. Результаты и выводы. Рациональным признан способ передачи нагрузки только на бетонное ядро усиленных колонн, поскольку устройство оголовка стальной обоймы требует применения сложных конструктивно-технологических решений, но при этом дополнительно увеличивает несущую способность незначительно (согласно проведенным исследованиям менее чем на 10 %). Ввиду отсутствия необходимости устройства конструкций стального оголовка снижаются трудоемкость и сроки производства работ по усилению колонн. Statement of the problem. The method of strengthening reinforced concrete columns with a steel clipping and the concrete surfacing is investigated. This method allows one to repair the columns with significant defects and damage. The prerequisite for this study was the assumption of strengthening with a steel clipping and the concrete surfacing is an effective way to increase the ultimate limit state of reinforced concrete columns, furthermore, the option of applying the load (only to the concrete core or to the entire section) does not significantly affect the strengthening effectiveness. In this regard, the purpose of the investigation was to identify the need to include the steel jacketing in the work, on the condition the column is coated with concrete along with the entire height. Results and conclusions. The load transfer method only to the concrete core of the strengthened columns is recognized as rational since the device of the steel clipping head requires the use of complex structural and technological solutions, but at the same time additionally increases the ultimate limit state insignificantly (according to the studies by less than 10 %). Due to the absence of the need to establish structures of the steel jacketing head, the labor intensiveness and terms of work production on strengthening the columns are reduced.

Explosive caldera-forming eruptions and debris-filled vents: Gargle dynamics

Large explosive volcanic eruptions are commonly associated with caldera subsidence and ignimbrites deposited by pyroclastic currents. Volumes and thicknesses of intracaldera and outflow ignimbrites at 76 explosive calderas around the world indicate that subsidence is commonly simultaneous with eruption, such that large proportions of the pyroclastic currents are trapped within the developing basins. As a result, much of an eruption must penetrate its own deposits, a process that also occurs in large, debris-filled vent structures even in the absence of caldera formation and that has been termed “gargling eruption.” Numerical modeling of the resulting dynamics shows that the interaction of preexisting deposits (fill) with an erupting (juvenile) mixture causes a dense sheath of fill material to be lifted along the margins of the erupting jet. This can cause an eruption that would otherwise produce a buoyant plume and fallout deposits to instead form pyroclastic currents as the dense sheath drives pulsing jet behavior. Increasing thickness of fill amplifies the time variation in jet height. Increasing the fill grain size relative to that of the juvenile particles can result in a much higher jet due to poorer mixing between the dense sheath and the dilute jet core. In all cases, material collapses along the entire height of the dense sheath rather than from the top of a simple fountain. These gargle dynamics provide strong backing for processes that have been inferred to result in intraplinian ignimbrites and simultaneous deposition from high- and low-energy pyroclastic currents.

A Potential Mitigation Measure of the Seismic Distress of the Circuit Wall at the Acropolis of Athens

The seismic design of new retaining structures is usually performed following modern seismic norms. Nonetheless, there are various monumental retaining structures (e.g., fortifications) with high seismic vulnerability, which must be protected against earthquakes, while there are several limitations on the type of mitigation measures that can be applied to such cultural heritage structures. The present study investigates numerically the seismic response and distress of the Circuit Wall of the Athenian Acropolis. The Wall is a monumental masonry retaining structure surrounding the world-class monuments of the archeological hill of the Acropolis. Given the fact that the wider region of Athens is characterized by moderate to high seismicity, it is necessary to protect the Wall from strong ground motions. For this purpose, the geological, seismological, and topographic conditions of the Acropolis hill, as well as the geometry and the mechanical properties of the Wall, are realistically taken into account. A representative finite-element model has been developed for a critical section of the Wall, which has been validated with available records from accelerometers being installed at the Wall. Subsequently, an efficient and suitable -according to international monument restoration guidelines- seismic mitigation measure is proposed. The results of dynamic earth-pressure distribution on the Wall are presented before and after the application of expanded polystyrene (EPS) blocks behind the Wall. Α detailed parametric study illustrates a substantial reduction of dynamic pressures on the Wall when the EPS blocks are applied, either along the entire height or only at the lower part of the Wall.

Thermal analysis of a solar hybrid dehydrator designed for uniform multi-product drying

Thermal analysis was performed for a vertical cabinet solar hybrid dryer having a salient feature of perforated sheet along its entire height to achieve uniform drying. The dryer was integrated with a solar collector and gas burner for hybrid heating source. Experiments were performed using tomato at 55°C with solar, gas, and dual (solar-gas) heating sources. Energy analysis showed that rates of energy utilization were found in ranges of 2.7-12.5 kW (dual), 3-13 kW (gas), 2.9-12 kW (solar) and energy ratios were 13-56% (dual), 14-58% (gas), 12-50% (solar). Exergy analysis showed that exergy losses were 2.1-5.0 kJ/kg (dual), 2.1-5.3 kJ/kg (gas) 1.5-4.2 kJ/kg (solar) while exergy efficiencies found 33-70% (dual), 30-75% (gas), 20-69% (solar). Based on higher values of exergetic factor and improvement potential rate (IP), it was found that optimization of heating source especially those consisting solar collector and heat exchanger (IP 1.93 kW) is required. The specific energies for the removal of product moisture and to dry the product were found 2.42, 2.72, 2.58 MJ/kg of water and 18.8, 21.2, 20.15 MJ/kg dried product for drying processes conducted under solar, gas, and dual (solar-gas) heating sources respectively. For design optimization, a complete algorithm has been prepared for complete drying systems in terms of available energy and losses.

Еlectronic fire safety systems efficiency in the combustion zone of cars for underground parkings of residential buildings

In this paper we presents the results of tests of automatic fire alarm systems in terms of reducing the temperature effect on building structures (floors), air ducts of the exhaust smoke ventilation system. Tests were carried out to determine the efficiency of the antismoke ventilation system for the removal of combustion products through steel air ducts with a metal thickness of 1 mm, as well as analysis of the temperature regime on building structures, the air duct of the exhaust smoke ventilation system under fire exposure. For the warning system (SO) of the second type, CO-2 we used on the basis of ISO “Bolid” devices. The launch of a fire warning system is provided for: automatically from an automatic fire extinguishing system; remotely from manual fire detectors installed at emergency exits from the vehicle storage room. Two full-scale firing tests were carried out for passenger cars. During the tests, the vehicles were ignited from inside the passenger compartment. In the course of the fire tests proved that the antismoke control ventilation ducts retained their integrity and tightness, which was confirmed by the positive protocols of aerodynamic tests of the smoke control ventilation system. The air ducts of the exhaust smoke ventilation system retained their integrity, the flange connections of the air ducts retained their strength and tightness, the fastenings of the air ducts were not damaged and retained their functions. The tests established the following: limitation of the fire center in the horizontal projection of the vehicle (the perimeter of the vehicle); filling the volume of the storage room for vehicles with a smoke-steam-air mixture occurs in an avalanche manner over the entire height of the room; as a result of the avalanche-like filling of the room, the absence of a neutral zone (security zone) was determined. Based on the results of the tests, it is possible to make changes to the existing technical normative legal acts.

Emergency condition of loggies in buildings with supporting brick walls

This article is devoted to the problems of the existing residential buildings of 70-80 years of construction of the last century, which have been in operation for about 50 years and are subject to immediate technical inspection. The most important factor for the safe operation of such buildings is the quality of construction, as in this period the construction was performed with many shortcomings that are manifested today. The article describes the problem of joints of loggias with the building in the design and construction of multi-storey buildings with load-bearing brick walls. Poor ligation of bricks in the masonry, as well as the lack of quality ligation of the transverse walls of loggias with load-bearing longitudinal walls of the building leads to the formation of cracks on the entire height of the loggias, which completely cut them at the abutment, which creates an emergency collapse of building structures. A real example of such a problem in the existing 9-storey building with brick load-bearing walls, where the shortcomings of construction were manifested, namely the poor quality of masonry at the junction of loggias to the load-bearing walls of the building. The structural scheme is also described, as well as the main structures of the building. The main damages and defects are shown. Using the PC "LIRA-SAPR" created a calculation model and compared the results of calculations with the existing condition of the considered area of the building. Recommendations for strengthening the emergency section of the building are given.

LABORATORY STUDY OF PARAMETERS OF CONTOUR BLASTING IN THE FORMATION OF SLOPES OF THE SIDES OF THE CAREER

Explored theoretically the interaction of explosive charges in the preliminary gap formation in quarries. A methodology has been developed for conducting experimental studies of blast well contour explosions on models, which allows one to investigate crack formation on volumetric models and wave interaction using high-speed video recording of the explosion process in transparent models, as well as determine the parameters of explosion stress waves in samples of real rocks. Theoretical and laboratory researches have established that only the creation of a screening gap for the entire height of the non-working ledge allows you to get a virtually undisturbed array with a high-quality surface of the slope