Artículos de revistas: "Burner (H.M. Ship)"

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Yang, M., B. J. Huebert, B. W. Blomquist, S. G. Howell, L. M. Shank, C. S. McNaughton, A. D. Clarke et al. "Atmospheric sulfur cycling in the southeastern Pacific – longitudinal distribution, vertical profile, and diel variability observed during VOCALS-REx". Atmospheric Chemistry and Physics 11, n.º 10 (31 de mayo de 2011): 5079–97. http://dx.doi.org/10.5194/acp-11-5079-2011.

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Abstract. Dimethylsulfide (DMS) emitted from the ocean is a biogenic precursor gas for sulfur dioxide (SO2) and non-sea-salt sulfate aerosols (SO42−). During the VAMOS-Ocean-Cloud-Atmosphere-Land Study Regional Experiment (VOCALS-REx) in 2008, multiple instrumented platforms were deployed in the Southeastern Pacific (SEP) off the coast of Chile and Peru to study the linkage between aerosols and stratocumulus clouds. We present here observations from the NOAA Ship Ronald H. Brown and the NSF/NCAR C-130 aircraft along ~20° S from the coast (70° W) to a remote marine atmosphere (85° W). While SO42− and SO2 concentrations were distinctly elevated above background levels in the coastal marine boundary layer (MBL) due to anthropogenic influence (~800 and 80 pptv, respectively), their concentrations rapidly decreased west of 78° W (~100 and 25 pptv). In the remote region, entrainment from the free troposphere (FT) increased MBL SO2 burden at a rate of 0.05 ± 0.02 μmoles m−2 day−1 and diluted MBL SO42 burden at a rate of 0.5 ± 0.3 μmoles m−2 day−1, while the sea-to-air DMS flux (3.8 ± 0.4 μmoles m−2 day−1) remained the predominant source of sulfur mass to the MBL. In-cloud oxidation was found to be the most important mechanism for SO2 removal and in situ SO42− production. Surface SO42− concentration in the remote MBL displayed pronounced diel variability, increasing rapidly in the first few hours after sunset and decaying for the rest of the day. We theorize that the increase in SO42− was due to nighttime recoupling of the MBL that mixed down cloud-processed air, while decoupling and sporadic precipitation scavenging were responsible for the daytime decline in SO42−.

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Barberán Nazareno, José L. y José R. Marín López. "Determinación de los parámetros de productividad en los procesos de carenamiento en un varadero mediano". Ciencia y tecnología de buques 3, n.º 6 (30 de enero de 2010): 53. http://dx.doi.org/10.25043/19098642.24.

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Productivity parameters were determined in maintenance works of 16 ships in the slipways of ASTINAVE, a medium-size shipyard at Guayaquil, Ecuador, in the period between April 2008 and January 2009. Typical processes applied during ship maintenance, its units for evaluation and a classification chart are presented. With the registered time (Man-Hour, M-H), mean values, standard deviations and variation coefficients were calculated for each process. Mean value results for each work were: Plating replacement: 0.220 M-H/kg, Hull cleaning: 0.435 M-H/m2-machine, Painting: 0.027 M-H/m2-machine, Cathodic protection: 0.116 M-H/Kg, Thickness measurement: 0.030 M-H/test, Propulsion system: 130.92 M-H/line, Steering system: 54.89 M-H/line, Ship docking/undocking: 43.97 M-H/maneuver, Bottom Valves: 15.83 M-H/#valve, and, Fuel tank cleaning: 0.0093 M-H/gal.

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Grue, John. "Ship generated mini-tsunamis". Journal of Fluid Mechanics 816 (3 de marzo de 2017): 142–66. http://dx.doi.org/10.1017/jfm.2017.67.

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Very long waves are generated when a ship moves across an appreciable depth change $\unicode[STIX]{x0394}h$ comparable to the average and relatively shallow water depth $h$ at the location, with $\unicode[STIX]{x0394}h/h\simeq 1$. The phenomenon is new and the waves were recently observed in the Oslofjord in Norway. The 0.5–1 km long waves, extending across the 2–3 km wide fjord, are observed as run-ups and run-downs along the shore, with periods of 30–60 s, where a wave height up to 1.4 m has been measured. The waves travelling with the shallow water speed, found ahead of the ships moving at subcritical depth Froude number, behave like a mini-tsunami. A qualitative explanation of the linear generation mechanism is provided by an asymptotic analysis, valid for $\unicode[STIX]{x0394}h/h\ll 1$ and long waves, expressing the generation in terms of a pressure impulse at the depth change. Complementary fully dispersive calculations for $\unicode[STIX]{x0394}h/h\simeq 1$ document symmetries of the waves at positive or negative $\unicode[STIX]{x0394}h$. The wave height grows with the ship speed $U$ according to $U^{n}$ with $n$ in the range 3–4, for $\unicode[STIX]{x0394}h/h\simeq 1$, while the growth in $U$ is only very weak for $\unicode[STIX]{x0394}h/h\ll 1$ (the asymptotics). Calculations show good agreement with observations.

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L. Smialek, James. "Relative Ti2AlC Scale Volatility under 1300 °C Combustion Conditions". Coatings 10, n.º 2 (5 de febrero de 2020): 142. http://dx.doi.org/10.3390/coatings10020142.

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Turbine environments may degrade high temperature ceramics because of volatile hydroxide reaction products formed in water vapor. Accordingly, the volatility of transient TiO2 and steady-state Al2O3 scales formed on the oxidation-resistant Ti2AlC MAX phase ceramic was examined in 1300 °C high velocity (Mach 0.3, 100 m/s) and high pressure (6 atm, 25 m/s) burner rig tests (BRT). Unlike metals, the ceramic was stable at 1300 °C. Unlike SiC and Si3N4, neither burner test produced a weight loss, unless heavily pre-oxidized. Lower mass gains were produced in the BRT compared to furnace tests. The commonly observed initial, fast TiO2 transient scale was preferentially removed in hot burner gas (~10% water vapor). A lesser degree of gradual Al2O3 volatilization occurred, indicated by grain boundary porosity and crystallographic etching. Modified cubic-linear (growth-volatility) kinetics are suggested. Gas velocity and water vapor pressure play specific roles for each scale. Furthermore, a 7YSZ TBC on Ti2AlC survived for 500 h in the Mach 0.3 burner test at 1300 °C with no indication of volatility or spalling.

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5

Allan, Robert G. y Peter Woodward. "Ship-Handling in the Port of Churchill—The “Bear” Essentials". Marine Technology and SNAME News 25, n.º 03 (1 de julio de 1988): 190–204. http://dx.doi.org/10.5957/mt1.1988.25.3.190.

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This paper describes an indepth study performed by the authors' company to properly determine the ship-handling requirements in the Port of Churchill, on Canada's Hudson Bay, and the subsequent design and construction of the 3000-hp tugboat, H. M. Wilson. This tug is unusual primarily because of the unique and remote location of the port in which it operates, and by the limitations which this remote site placed upon its design and construction. Hudson Bay ship-berthing tug H. M. Wilson

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Syafiul, Ahmad. "KAJIAN DAMAGE STABILITY PADA STUDI KELAYAKAN DESAIN KAPAL BARGE PENAMBANG TIMAH DENGAN PENDEKATAN METODE NUMERIK". INOVTEK POLBENG 9, n.º 2 (28 de noviembre de 2019): 334. http://dx.doi.org/10.35314/ip.v9i2.1123.

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Nearly 90% of ship accidents or ship sinking are caused by leakage. Tin Mining Barge Vessel is an interesting research object because there are various challenges that are being faced in designing, arranging, and constructing tin mining vessels, especially regarding stability studies when a ship has a leak. Tin Mining Barge Vessel has a displacement (Δ) = 3025 tons, length (LoA) = 68 m, Width (B) = 17 m, High (H) = 5 m, Sarat (T) = 3 m. The configuration of the stability simulation of The Tin Mining Barge Vessel uses a variation of 1 intact case and 15 damage cases where simulated compartments around the ship's hole have leakage and then calculated its stability value and compared the results with IMO Code A.749 (18) Ch 3 and IMO regulations SOLAS requirements Chapter II Part B-1. From the results of the study, it can be concluded that the ship becomes unstable if there is a leak in the compartment on one side of the hole of the ship such as the Void 3 and 4 compartments at Portside (P) or on the Starboard (S). Overall, it can be concluded that the Tin Mining Barge Vessel will be instability when a leak occurs. The solution is conducted by adding the installation of a watertight length with a distance of 1200 mm in the compartment: Void 3 (P), Void 4 (P), Void 3 (P), and Void 4 (S).

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Tresnadi, Agung, Suparno Suparno, Sutrisno Sutrisno y Wawan Kusdiana. "TIME ACCELERATION ANALYSIS AND OPTIMAL COST OF HOSPITAL HOSPITAL DEVELOPMENT PROJECT ON SHIP BUILDING USING CRITICAL PATH METHOD (CASE STUDY: PT. PAL INDONESIA (PERSERO))". JOURNAL ASRO 12, n.º 01 (18 de enero de 2021): 137. http://dx.doi.org/10.37875/asro.v12i01.390.

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Hospital Auxiliary Ship is an Indonesian Navy ship produced by PT. PAL Indonesia (Persero). The construction of this BRS ship was very time consuming and one of the main parts of the ship building project was the construction of the hull structure. In relation to time and production costs, the shipyard must be as efficient as possible in the use of time in each activity or activity, so that costs can be minimized from the original plan. Acceleration of the total duration in a project is done by accelerating critical activities in the project. To find out which are the critical activities of a project, the Critical Path Method (CPM) technique is used; namely by drawing a Network Diagram of the project. By using the CPM method in scheduling a ship hull construction project, it can be seen which activities should take precedence so as not to experience delays and waste. After that, the crashing method is carried out by increasing work hours (overtime) which aims to speed up the time of the project. The results of research for activities that are in the initial critical path with the CPM method can be seen as activities A, C, H, M, R, W, AB, AC, AD, AI, AP, AT, BA, BJ, BN. After accelerating, the critical path activities include activities A, C, H, M, R, W, X, AC, AD, AI, AP, AT, BA, BH, BO. Calculation of the project during initial conditions with Early working days without using overtime hours PT PAL Indonesia (Persero) costs Rp. 5,299,631,000, - while the Crashing Method is through the addition of 1 hour / day overtime so that the project implementation can be accelerated from the initial implementation of 450 days to 412 days and PT. PAL Indonesia (Persero) issued a project cost of Rp. 5,323,752,480, -. Keywords: Hospital Support Ship, Scheduling, CPM, Crashing.

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Xue, Han y Tian Chai. "Path Optimization along Buoys Based on the Shortest Path Tree with Uncertain Atmospheric and Oceanographic Data". Computational Intelligence and Neuroscience 2021 (27 de febrero de 2021): 1–7. http://dx.doi.org/10.1155/2021/6663446.

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In order to design an optimized route for ships in line with economic benefits; avoid bad weather; reduce unnecessary detours; shorten the navigation time; and achieve the purpose of safety, fuel saving, and punctual arrival, this paper takes the navigation mark as the node of the tree, takes the connection of the adjacent navigation marks as the tree path, and divides the distance of the adjacent buoys by the ship’s speed as the path cost. The speed calculation collects the current hydrometeorological data such as wind and wave data, uses Aertssen’s deceleration formula to adjust the speed, and improves Dijkstra to find the shortest path. In the experiment, two routes from Dongdu to Xiamen Gang Kou are compared under bad weather conditions. Route 1 is with 5.877 m/s average wind speed, 0.860 m/s wave speed, and total distance 34717 m. Route 2 is with 8.503 m/s average wind speed, 1.429 m/s wave speed, and total distance 30223 m. The calculated ship speed travelling in route 1 is 12.243 km, and its travelling time is 1.53 h. The calculated ship speed travelling in route 2 is 10.523 km, and its travelling time is 1.55 h. Although the total distance of route 1 is longer, it takes less time for ships to travel in route 1. The experimental results verify the effectiveness of the navigation algorithm based on the shortest path tree of uncertain weather maps.

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9

Berner, A. H., C. S. Bretherton y R. Wood. "Large eddy simulation of ship tracks in the collapsed marine boundary layer: a case study from the Monterey area ship track experiment". Atmospheric Chemistry and Physics 15, n.º 10 (27 de mayo de 2015): 5851–71. http://dx.doi.org/10.5194/acp-15-5851-2015.

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Abstract. For the first time, a large eddy simulation (LES) coupled to a bulk aerosol scheme is used to simulate an aircraft-sampled ship track. The track was formed by the M/V Sanko Peace on 13 June 1994 in a shallow drizzling boundary layer with high winds but very low background aerosol concentrations (10 cm−3). A Lagrangian framework is used to simulate the evolution of a short segment of track as it is advected away from the ship for 8 h (a downwind distance exceeding 570 km). Using aircraft observations for initialization, good agreement is obtained between the simulated and observed features of the ambient boundary layer outside the track, including the organization of the cloud into mesoscale rolls. After 8 h, a line of aerosol is injected to start the ship track. The simulation successfully reproduces the significant albedo enhancement and suppression of drizzle observed within the track. The aerosol concentration within the track dilutes as it broadens due to turbulent mixing. A sensitivity study shows the broadening rate strongly depends on the alignment between the track and the wind-aligned boundary layer rolls, as satellite images of ship tracks suggest. Entrainment is enhanced within the simulated track, but the observed 100 m elevation of the ship track above the surrounding layer is not simulated, possibly because the LES quickly sharpens the rather weak observed inversion. Liquid water path within the simulated track increases with time even as the ambient liquid water path is decreasing. The albedo increase in the track from liquid water and cloud fraction enhancement (second indirect effect) eventually exceeds that from cloud droplet number increases (first indirect or Twomey effect). In a sensitivity study with a higher initial ambient aerosol concentration, stronger ship track aerosol source, and much weaker drizzle, there is less liquid water inside the track than outside for several hours downwind, consistent with satellite estimates for such situations. In that case, the Twomey effect dominates throughout, although, as seen in satellite images, the albedo enhancement of the track is much smaller.

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Bariteau, L., D. Helmig, C. W. Fairall, J. E. Hare, J. Hueber y E. K. Lang. "Determination of oceanic ozone deposition by ship-borne eddy covariance flux measurements". Atmospheric Measurement Techniques Discussions 2, n.º 4 (19 de agosto de 2009): 1933–72. http://dx.doi.org/10.5194/amtd-2-1933-2009.

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Abstract. A fast response ozone analyzer based on the ozone-nitric oxide chemiluminescence method was integrated into the NOAA-ESRL flux system to achieve the first ship-borne, direct ozone flux measurements over the open ocean. Air was collected from an inlet at 18 m height over the ocean surface mounted to the bow-jackstaff and via a 30 m-long sampling line to the ozone instrument on the ship deck. A "puff" system was used for accurate and regular determination of the sample transport time (lag) between the inlet and the chemical analyzer. A Nafion-membrane dryer facilitated removal of fast water vapor fluctuations, which eliminated the need for quenching and density correction of the ozone signal. The sampling-analyzer system was found to have a ~0.25–0.40 s response time at a sensitivity of ~2800 counts s−1 per ppbv of ozone. Quality control and data filtering procedures for eliminating data that did not meet measurement requirements were critically evaluated. The new ozone flux system was deployed during several cruises aboard the NOAA Ship Ronald H. Brown, and evaluated using results obtained during several research cruises off the coasts of the North and South America continents.

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Alford, Matthew H., Michael C. Gregg y Eric A. D’Asaro. "Mixing, 3D Mapping, and Lagrangian Evolution of a Thermohaline Intrusion". Journal of Physical Oceanography 35, n.º 9 (1 de septiembre de 2005): 1689–711. http://dx.doi.org/10.1175/jpo2780.1.

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Abstract Observations of the three-dimensional structure and evolution of a thermohaline intrusion in a wide, deep fjord are presented. In an intensive two-ship study centered on an acoustically tracked neutrally buoyant float, a cold, fresh, low-oxygen tongue of water moving southward at about 0.03 m s−1 out of Possession Sound, Washington, was observed. The feature lay across isopycnal surfaces in a 50–80-m depth range. The large-scale structures of temperature, salinity, velocity, dissolved oxygen, and chlorophyll were mapped with a towed, depth-cycling instrument from one ship while the other ship measured turbulence close to the float with loosely tethered microstructure profilers. Observations from both ships were expressed in a float-relative (Lagrangian) reference frame, minimizing advection effects. A float deployed at the tongue’s leading edge warmed 0.2°C in 24 h, which the authors argue resulted from mixing. Diapycnal heat fluxes inferred from microstructure were 1–2 orders of magnitude too small to account for the observed warming. Instead, lateral stirring along isopycnals appears responsible, implying isopycnal diffusivities O(1 m2 s−1). These are consistent with estimates, using measured temperature microstructure, from an extension of the Osborn–Cox model that allows for lateral gradients. Horizontal structures with scales O(100 m) are seen in time series and spatial maps, supporting this interpretation.

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Nylund, Amanda T., Lars Arneborg, Anders Tengberg, Ulf Mallast y Ida-Maja Hassellöv. "In situ observations of turbulent ship wakes and their spatiotemporal extent". Ocean Science 17, n.º 5 (27 de septiembre de 2021): 1285–302. http://dx.doi.org/10.5194/os-17-1285-2021.

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Abstract. In areas of intensive ship traffic, ships pass every 10 min. Considering the amount of ship traffic and the predicted increase in global maritime trade, there is a need to consider all types of impacts shipping has on the marine environment. While the awareness about, and efforts to reduce, chemical pollution from ships is increasing, less is known about physical disturbances, and ship-induced turbulence has so far been completely neglected. To address the potential importance of ship-induced turbulence on, e.g., gas exchange, dispersion of pollutants, and biogeochemical processes, a characterisation of the temporal and spatial scales of the turbulent wake is needed. Currently, field measurements of turbulent wakes of real-size ships are lacking. This study addresses that gap by using two different methodological approaches: in situ and ex situ observations. For the in situ observations, a bottom-mounted acoustic Doppler current profiler (ADCP) was placed at 32 m depth below the shipping lane outside Gothenburg harbour. Both the acoustic backscatter from the air bubbles in the wake and the dissipation rate of turbulent kinetic energy were used to quantify the turbulent wake depth, intensity, and temporal longevity for 38 ship passages of differently sized ships. The results from the ADCP measurements show median wake depths of 13 m and several occasions of wakes reaching depths > 18 m, which is in the same depth range as the seasonal thermocline in the Baltic Sea. The temporal longevity of the observable part of the wakes had a median of around 10 min and several passages of > 20 min. In the ex situ approach, sea surface temperature was used as a proxy for the water mass affected by the turbulent wake (thermal wake), as lowered temperature in the ship wake indicates vertical mixing in a thermally stratified water column. Satellite images of the thermal infrared sensor (TIRS) onboard Landsat-8 were used to measure thermal wake width and length, in the highly frequented and thus major shipping lane north of Bornholm, Baltic Sea. Automatic information system (AIS) records from both the investigated areas were used to identify the ships inducing the wakes. The satellite analysis showed a median thermal wake length of 13.7 km (n=144), and the longest wake extended over 60 km, which would correspond to a temporal longevity of 1 h 42 min (for a ship speed of 20 kn). The median thermal wake width was 157.5 m. The measurements of the spatial and temporal scales are in line with previous studies, but the maximum turbulent wake depth (30.5 m) is deeper than previously reported. The results from this study, combined with the knowledge of regional high traffic densities, show that ship-induced turbulence occurs at temporal and spatial scales large enough to imply that this process should be considered when estimating environmental impacts from shipping in areas with intense ship traffic.

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de Szoeke, S. P., C. W. Fairall y Sergio Pezoa. "Ship Observations of the Tropical Pacific Ocean along the Coast of South America". Journal of Climate 22, n.º 2 (15 de enero de 2009): 458–64. http://dx.doi.org/10.1175/2008jcli2555.1.

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Abstract In October 2007 the NOAA ship Ronald H. Brown sailed southward within 300 km of the coast of Ecuador and Peru, sampling surface meteorology, air–sea turbulent and radiative fluxes, cloud properties, and upper-air soundings from the equator to 20°S. Two distinct water masses characterize the coastal region: cold-pool water below 19°C in the Southern Hemisphere, and warm-pool water above 20°C to the north, with a transition between the water masses at 2.5°S. Net turbulent and radiative fluxes warm the cool water south of 2.5°S by 100 W m−2 but do not warm the equatorial water significantly. Winds blow parallel to the shore, about 5 m s−1 over the cold pool and 7 m s−1 over the equator. Stratocumulus clouds are remarkably solid over the coastal cold pool, with only brief periods of partial clearing, mostly in the afternoon. Lower aerosol concentrations and thicker clouds observed farther from the coast on 22–23 October are coincident with a pocket of open cells seen to the west and southwest of the ship. Observations from this cruise and other NOAA Stratus cruises (2001 and 2003–07) are suitable for comparison with model simulations and provide context for future field experiments. These datasets are publicly available.

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Bariteau, L., D. Helmig, C. W. Fairall, J. E. Hare, J. Hueber y E. K. Lang. "Determination of oceanic ozone deposition by ship-borne eddy covariance flux measurements". Atmospheric Measurement Techniques 3, n.º 2 (12 de abril de 2010): 441–55. http://dx.doi.org/10.5194/amt-3-441-2010.

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Abstract. A fast response ozone analyzer based on the ozone-nitric oxide chemiluminescence method was integrated into the NOAA-ESRL flux system to achieve the first ship-borne, direct ozone flux measurements over the open ocean. Air was collected from an inlet at 18 m height over the ocean surface mounted to the bow-jackstaff and via a 30 m-long sampling line to the ozone instrument on the ship deck. A "puff" system was used for accurate and regular determination of the sample transport time (lag) between the inlet and the chemical analyzer. A Nafion-membrane dryer facilitated removal of fast water vapor fluctuations, which eliminated the need for quenching and density correction of the ozone signal. The sampling-analyzer system was found to have a ~0.25–0.40 s response time at a sensitivity of ~2800 counts s−1 per ppbv of ozone. Quality control and data filtering procedures for eliminating data that did not meet measurement requirements were critically evaluated. The new ozone flux system was deployed aboard the NOAA Ship Ronald H. Brown, and evaluated using results obtained during several research cruises off the coasts of the North and South America continents, yielding ozone deposition velocities (mean ± standard error) ranging from 0.009±0.001 cm s−1 to 0.24±0.020 cm s−1.

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Prasetyo, Arif, Mohammad Danil Arifin y Endro Prabowo. "Application Savonius Turbine on Ferries 750 GT". KnE Energy 1, n.º 1 (1 de diciembre de 2015): 17. http://dx.doi.org/10.18502/ken.v1i1.341.

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Vessel operating costs the highest for purchase of fuel, with the increasingly limited oil reserves and the trend of oil price increases every year this is will add to the high operating costs. Important to start doing research for deploying renewable energy on the ship, especially to reduce the use of auxiliary engine on the ship. For renewable energy applications on ships using wind energy is available throughout the day. Application on the ship using savonius turbine, with high rotor 50 cm , diameters 40 cm , use of gear ratio to increase the rotation of the rotor and the generator 200 W. Assuming when a sail the wind speed 12 m/s and the results of the electricity generated by the generator is average of 100 Wh. With the early stages of the installation 20 units turbines, then the results electricity generated can reach 2.000 W x 24 h = 4.8 kWh/d. This is certainly a very promising result for future development. With continuously research can certainly achieve the best efficiency.Keywords: Renewable energy, Ship, Savonius turbine, Wind energy

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Becagli, Silvia, Fabrizio Anello, Carlo Bommarito, Federico Cassola, Giulia Calzolai, Tatiana Di Iorio, Alcide di Sarra et al. "Constraining the ship contribution to the aerosol of the central Mediterranean". Atmospheric Chemistry and Physics 17, n.º 3 (10 de febrero de 2017): 2067–84. http://dx.doi.org/10.5194/acp-17-2067-2017.

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Abstract. Particulate matter with aerodynamic diameters lower than 10 µm, (PM10) aerosol samples were collected during summer 2013 within the framework of the Chemistry and Aerosol Mediterranean Experiment (ChArMEx) at two sites located north (Capo Granitola) and south (Lampedusa Island), respectively, of the main Mediterranean shipping route in the Straight of Sicily. The PM10 samples were collected with 12 h time resolutions at both sites. Selected metals, main anions, cations and elemental and organic carbon were determined. The evolution of soluble V and Ni concentrations (typical markers of heavy fuel oil combustion) was related to meteorology and ship traffic intensity in the Straight of Sicily, using a high-resolution regional model for calculation of back trajectories. Elevated concentration of V and Ni at Capo Granitola and Lampedusa are found to correspond with air masses from the Straight of Sicily and coincidences between trajectories and positions of large ships; the vertical structure of the planetary boundary layer also appears to play a role, with high V values associated with strong inversions and a stable boundary layer. The V concentration was generally lower at Lampedusa than at Capo Granitola V, where it reached a peak value of 40 ng m−3. Concentrations of rare earth elements (REEs), La and Ce in particular, were used to identify possible contributions from refineries, whose emissions are also characterized by elevated V and Ni amounts; refinery emissions are expected to display high La ∕ Ce and La ∕ V ratios due to the use of La in the fluid catalytic converter systems. In general, low La ∕ Ce and La ∕ V ratios were observed in the PM samples. The combination of the analyses based on chemical markers, air mass trajectories and ship routes allows us to unambiguously identify the large role of the ship source in the Straight of Sicily. Based on the sampled aerosols, ratios of the main aerosol species arising from ship emission with respect to V were estimated with the aim of deriving a lower limit for the total ship contribution to PM10. The estimated minimum ship emission contributions to PM10 were 2.0 µg m−3 at Lampedusa and 3.0 µg m−3 at Capo Granitola, corresponding with 11 and 8.6 % of PM10, respectively.

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Cardona Vargas, Arley, Carlos E. Arrieta, Hernando Alexander Yepes Tumay, Camilo Echeverri-Uribe y Andrés Amell. "Determination of laminar burning velocity of methane/air flames in sub atmospheric environments". EUREKA: Physics and Engineering, n.º 4 (23 de julio de 2021): 50–62. http://dx.doi.org/10.21303/2461-4262.2021.001775.

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The global energy demand enhances the environmental and operational benefits of natural gas as an energy alternative, due to its composition, mainly methane (CH4), it has low polluting emissions and benefits in energy and combustion systems. In the present work, the laminar burning velocity of methane was determined numerically and experimentally at two pressure conditions, 0.85 atm and 0.98 atm, corresponding to the city of Medellín and Caucasia, respectively, located in Colombia. The environmental conditions were 0.85 atm, 0.98 atm, and 295±1 K. The simulations and experimental measurements were carried out for different equivalence relations. Experimental laminar burning velocities were determined using the burner method and spontaneous chemiluminescence technique, flames were generated using burners with contoured rectangular ports to maintain laminar Reynolds numbers for the equivalence ratios under study and to reduce the effects of stretch and curvature in the direction of the burner's axis. In general, the laminar burning velocity fits well with the numerical results. With the results obtained, a correlation is proposed that relates the laminar burning velocity with the effects of pressure, in the form SL=aPb, where a and b are model constants. Sensitivity analysis was performed using the GRI-Mech 3.0 mechanism which showed that the most sensitive reaction was H+O2=O+OH (R38). Additionally, it was found that the reactions H+CH3 (+M)=CH4 (+M) (R52), 2CH3 (+M)=C2H6 (+M) (R158), and O+CH3=H+CH2O (R10) dominate the consumption of CH3 which is an important radical in the oxidation of methane, this analysis is carried out for equivalence ratios of 0.8 and 1.0, and atmospheric pressures of 0.85 atm and 0.98 atm

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Bennke, Christin M., Greta Reintjes, Martha Schattenhofer, Andreas Ellrott, Jörg Wulf, Michael Zeder y Bernhard M. Fuchs. "Modification of a High-Throughput Automatic Microbial Cell Enumeration System for Shipboard Analyses". Applied and Environmental Microbiology 82, n.º 11 (25 de marzo de 2016): 3289–96. http://dx.doi.org/10.1128/aem.03931-15.

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ABSTRACTIn the age of ever-increasing “-omics” studies, the accurate and statistically robust determination of microbial cell numbers within often-complex samples remains a key task in microbial ecology. Microscopic quantification is still the only method to enumerate specific subgroups of microbial clades within complex communities by, for example, fluorescencein situhybridization (FISH). In this study, we improved an existing automatic image acquisition and cell enumeration system and adapted it for usage at high seas on board an oceanographic research ship. The system was evaluated by testing settings such as minimal pixel area and image exposure times ashore under stable laboratory conditions before being brought on board and tested under various wind and wave conditions. The system was robust enough to produce high-quality images even with ship heaves of up to 3 m and pitch and roll angles of up to 6.3°. On board the research ship, on average, 25% of the images acquired from plankton samples on filter membranes could be used for cell enumeration. Automated enumeration was highly correlated with manual counts (r2> 0.9). Even the smallest of microbial cells in the open ocean, members of the alphaproteobacterial SAR11 clade, could be confidently detected and enumerated. The automated image acquisition and cell enumeration system developed here enables an accurate and reproducible determination of microbial cell counts in planktonic samples and allows insight into the abundance and distribution of specific microorganisms already on board within a few hours.IMPORTANCEIn this research article, we report on a new system and software pipeline, which allows for an easy and quick image acquisition and the subsequent enumeration of cells in the acquired images. We put this pipeline through vigorous testing and compared it to manual microscopy counts of microbial cells on membrane filters. Furthermore, we tested this system at sea on board a marine research vessel and counted bacteria on board within a few hours after the retrieval of water samples. The imaging and counting system described here has been successfully applied to a number of laboratory-based studies and allowed the quantification of thousands of samples and FISH preparations (see, e.g., H. Teeling, B. M. Fuchs, D. Becher, C. Klockow, A. Gardebrecht, C. M. Bennke, M. Kassabgy, S. Huang, A. J. Mann, J. Waldmann, M. Weber, A. Klindworth, A. Otto, J. Lange, J. Bernhardt, C. Reinsch, M. Hecker, J. Peplies, F. D. Bockelmann, U. Callies, G. Gerdts, A. Wichels, K. H. Wiltshire, F. O. Glöckner, T. Schweder, and R. Amann, Science 336:608–611, 2012,http://dx.doi.org/10.1126/science.1218344). We adjusted the standard image acquisition software to withstand ship movements. This system will allow for more targeted sampling of the microbial community, leading to a better understanding of the role of microorganisms in the global oceans.

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Fuhlbrügge, S., B. Quack, S. Tegtmeier, E. Atlas, H. Hepach, Q. Shi, S. Raimund y K. Krüger. "The contribution of oceanic halocarbons to marine and free troposphere air over the tropical West Pacific". Atmospheric Chemistry and Physics Discussions 15, n.º 13 (2 de julio de 2015): 17887–943. http://dx.doi.org/10.5194/acpd-15-17887-2015.

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Abstract. Emissions of halogenated very short lived substances (VSLS) from the tropical oceans contribute to the atmospheric halogen budget and affect tropospheric and stratospheric ozone. Here we investigate the contribution of natural oceanic VSLS emissions to the Marine Atmospheric Boundary Layer (MABL) and their transport into the Free Troposphere (FT) over the tropical West Pacific. The study concentrates in particular on ship and aircraft measurements of the VSLS bromoform, dibromomethane and methyl iodide and meteorological parameters during the SHIVA (Stratospheric Ozone: Halogen Impacts in a Varying Atmosphere) campaign in the South China and Sulu Seas in November 2011. Elevated oceanic concentrations of 19.9 (2.80–136.91) pmol L−1 for bromoform, 5.0 (2.43–21.82) pmol L−1 for dibromomethane and 3.8 (0.55–18.83) pmol L−1 for methyl iodide in particular close to Singapore and at the coast of Borneo with high corresponding oceanic emissions of 1486 ± 1718 pmol m−2 h−1 for bromoform, 405 ± 349 pmol m−2 h−1 for dibromomethane and 433 ± 482 pmol m−2 h−1 for methyl iodide characterize this tropical region as a strong source of these compounds. Unexpectedly atmospheric mixing ratios in the MABL were relatively low with 2.08 ± 2.08 ppt for bromoform, 1.17 ± 1.17 ppt for dibromomethane and 0.39 ± 0.09 ppt for methyl iodide. We use meteorological and chemical ship and aircraft observations, FLEXPART trajectory calculations and source-loss estimates to identify the oceanic VSLS contribution to the MABL and to the FT. Our results show that a convective, well-ventilated MABL and intense convection led to the low atmospheric mixing ratios in the MABL despite the high oceanic emissions in coastal areas of the South-China and Sulu Seas. While the accumulated bromoform in the FT above the region origins almost entirely from the local South China Sea area, dibromomethane is largely advected from distant source regions. The accumulated FT mixing ratio of methyl iodide is higher than can be explained with the local oceanic or MABL contributions. Possible reasons, uncertainties and consequences of our observations and model estimates are discussed.

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Sinreich, R., S. Coburn, B. Dix y R. Volkamer. "Ship-based detection of glyoxal over the remote tropical Pacific Ocean". Atmospheric Chemistry and Physics Discussions 10, n.º 6 (21 de junio de 2010): 15075–107. http://dx.doi.org/10.5194/acpd-10-15075-2010.

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Abstract. We present the first detection of glyoxal (CHOCHO) over the remote tropical Pacific Ocean in the Marine Boundary Layer (MBL). The measurements were conducted by means of the University of Colorado Ship Multi-Axis Differential Optical Spectroscopy (CU SMAX-DOAS) instrument aboard the research vessel Ronald H. Brown. The research vessel was on a cruise in the framework of the VAMOS Ocean-Cloud-Atmosphere-Land Study – Regional Experiment (VOCALS-REx) and the Tropical Atmosphere Ocean (TAO) projects lasting from October 2008 through January 2009 (74 days at sea). The CU SMAX-DOAS instrument features a motion compensation system to characterize the pitch and roll of the ship and to compensate for ship movements in real time. We found elevated mixing ratios of up to 170 ppt CHOCHO located inside the MBL up to 3000 km from the continental coast over biologically active upwelling regions of the tropical Eastern Pacific Ocean. This is surprising since CHOCHO is very short lived (atmospheric life time ~2 h) and highly water soluble (Henry's Law constant H=4.2×105 M/atm). This CHOCHO cannot be explained by transport of it or its precursors from continental sources. Rather, the open ocean is a source for CHOCHO to the atmosphere. Dissolved Organic Matter (DOM) photochemistry in surface waters is a source for Volatile Organic Compounds (VOCs) to the atmosphere, e.g. acetaldehyde. The extension of this mechanism to very soluble gases, like CHOCHO, is not straightforward since the air-sea flux is directed from the atmosphere into the ocean. For CHOCHO, the dissolved concentrations would need to be extremely high in order to explain our gas-phase observations by this mechanism (40–70 μM CHOCHO, compared to ~0.01 μM acetaldehyde and 60–70 μM DOM). Further, while there is as yet no direct measurement of VOCs in our study area, measurements of the CHOCHO precursors isoprene, and/or acetylene over phytoplankton bloom areas in other parts of the oceans are too low (by a factor of 10–100) to explain the observed CHOCHO amounts. We conclude that our CHOCHO data cannot be explained by currently understood processes. Yet, it supports first global source estimates of 20 Tg/year CHOCHO from the oceans, which likely is a significant source of secondary organic aerosol (SOA). This chemistry is currently not considered by atmospheric models.

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21

Sinreich, R., S. Coburn, B. Dix y R. Volkamer. "Ship-based detection of glyoxal over the remote tropical Pacific Ocean". Atmospheric Chemistry and Physics 10, n.º 23 (1 de diciembre de 2010): 11359–71. http://dx.doi.org/10.5194/acp-10-11359-2010.

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Abstract. We present the first detection of glyoxal (CHOCHO) over the remote tropical Pacific Ocean in the Marine Boundary Layer (MBL). The measurements were conducted by means of the University of Colorado Ship Multi-Axis Differential Optical Absorption Spectroscopy (CU SMAX-DOAS) instrument aboard the research vessel Ronald H. Brown. The research vessel was on a cruise in the framework of the VAMOS Ocean-Cloud-Atmosphere-Land Study – Regional Experiment (VOCALS-REx) and the Tropical Atmosphere Ocean (TAO) projects lasting from October 2008 through January 2009 (74 days at sea). The CU SMAX-DOAS instrument features a motion compensation system to characterize the pitch and roll of the ship and to compensate for ship movements in real time. We found elevated mixing ratios of up to 140 ppt CHOCHO located inside the MBL up to 3000 km from the continental coast over biologically active upwelling regions of the tropical Eastern Pacific Ocean. This is surprising since CHOCHO is very short lived (atmospheric life time ~2 h) and highly water soluble (Henry's Law constant H = 4.2 × 105 M/atm). This CHOCHO cannot be explained by transport of it or its precursors from continental sources. Rather, the open ocean must be a source for CHOCHO to the atmosphere. Dissolved Organic Matter (DOM) photochemistry in surface waters is a source for Volatile Organic Compounds (VOCs) to the atmosphere, e.g. acetaldehyde. The extension of this mechanism to very soluble gases, like CHOCHO, is not straightforward since the air-sea flux is directed from the atmosphere into the ocean. For CHOCHO, the dissolved concentrations would need to be extremely high in order to explain our gas-phase observations by this mechanism (40–70 μM CHOCHO, compared to ~0.01 μM acetaldehyde and 60–70 μM DOM). Further, while there is as yet no direct measurement of VOCs in our study area, measurements of the CHOCHO precursors isoprene, and/or acetylene over phytoplankton bloom areas in other parts of the oceans are too low (by a factor of 10–100) to explain the observed CHOCHO amounts. We conclude that our CHOCHO data cannot be explained by currently understood processes. Yet, it supports first global source estimates of 20 Tg/year CHOCHO from the oceans, which likely is a significant source of secondary organic aerosol (SOA). This chemistry is currently not considered by atmospheric models.

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22

Wilhelm, Eugen, Tobias Mente y Michael Rhode. "Waiting time before NDT of welded offshore steel grades under consideration of delayed hydrogen-assisted cracking". Welding in the World 65, n.º 5 (28 de enero de 2021): 947–59. http://dx.doi.org/10.1007/s40194-020-01060-5.

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AbstractOffshore wind turbines (OWT) are a major goal of the energy strategy of Germany encompassing the increase of the installed wind power. OWT components are manufactured from welded steel plates with thicknesses up to 200 mm. The underlying standards and technical recommendations for construction of OWTs encompass specifications of so-called minimum waiting time (MWT) before non-destructive testing of the weld joints is allowed. Reason is the increased risk of time-delayed hydrogen-assisted cold cracking as hydrogen diffusion is very slow due to the very thick plates. The strict consideration of those long MWT up to 48 h during the construction of OWTs leads to significant financial burden (like disproportionately high costs for installer ships as well as storage problems (onshore)). In this study, weld joints made of S355 ML were examined in comparison with the offshore steel grade S460 G2+M. The aim was to optimize, i.e., reduce, the MWT before NDT considering varied heat input, hydrogen concentration and using self-restraint weld tests. This would significantly reduce the manufacturing time and costs of OWT construction. To quantify the necessary delay time until hydrogen-assisted cold cracks appear, acoustic emission analysis was applied directly after welding for at least 48 h.

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23

Grosse, Maël, Roberto Pérez, Mateo Juan-Amengual, Joan Pons y María Capa. "The elephant in the room: first record of invasive gregarious species of serpulids (calcareous tube annelids) in Majorca (western Mediterranean)". Scientia Marina 85, n.º 1 (20 de abril de 2021): 15–28. http://dx.doi.org/10.3989/scimar.05062.002.

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Although there are several nuisance species of serpulids reported worldwide, the present study shows that some of them have been overlooked even in geographic areas that are considered well studied. We report for the first time in Majorca the invasive species Ficopomatus enigmaticus and the first records for the Balearic Islands of the also non-native species Hydroides dianthus, H. dirampha, H. elegans and H. nigra. The most abundant species were F. enigmaticus, found at higher densities in Portixol (with up to 280 ind. m–2), and H. elegans, found at highest densities in the port of Palma (with up to 270 ind. m–2). Species have been identified after morphological examination and corroborated by mitochondrial DNA sequence data: cytochrome c oxidase subunit 1 (COI) and cytochrome b (Cytb). Molecular data show that the same haplotypes have been found in distant and disjoint biogeographic areas worldwide, which is only explicable by unintentional translocation of specimens through vectors (i.e. ship hulls or ballast water). Species delimitation analyses support previous findings that species complexes are common in both Ficopomatus and Hydroides. In fact, only among the Majorcan samples were we able to detect three species of the F. enigmaticus species complex, two of the H. elegans species complex and two of the H. dianthus species complex. The genetic distances between members of the F. enigmaticus species complex are 8.7% to 16.7% in COI sequences. The species of Hydroides hold 5.4% to 47.6 % genetic divergence between species of the same complex.

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24

Szczodrak, Malgorzata, Peter J. Minnett, Nicholas R. Nalli y Wayne F. Feltz. "Profiling the Lower Troposphere over the Ocean with Infrared Hyperspectral Measurements of the Marine-Atmosphere Emitted Radiance Interferometer". Journal of Atmospheric and Oceanic Technology 24, n.º 3 (1 de marzo de 2007): 390–402. http://dx.doi.org/10.1175/jtech1961.1.

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Abstract Measurements of the spectra of infrared emission from the atmosphere were taken by a Marine-Atmospheric Emitted Radiance Interferometer (M-AERI) deployed on the NOAA ship Ronald H. Brown during the Aerosol and Ocean Science Expedition (AEROSE) in the tropical Atlantic Ocean from 29 February to 26 March 2004. The spectra are used to retrieve profiles of temperature and humidity in the lower troposphere up to a height of 3000 m. The M-AERI retrievals of the atmospheric structure require an initial guess profile. In this work, retrievals obtained from four separate initializations are compared, using 1) radiosondes launched from the Ronald H. Brown, 2) NOAA/NWS/NCEP model reanalyses, 3) ECMWF model analyses, and 4) ECMWF model forecasts. The performance of the M-AERI retrievals for all four first-guess sources is then evaluated against the radiosonde measurements. The M-AERI retrievals initialized using radiosondes reproduce the radiosonde profiles quite well and capture much of the observed vertical structure as should be expected. Of the retrievals initialized with model fields, those obtained using the ECMWF data yielded results closest to the radiosonde observations and enabled detection of the Saharan air layer (SAL) evident during AEROSE. However, the NCEP reanalysis, as well as the corresponding retrievals, failed to detect the SAL. These results demonstrate the ability of the M-AERI profile retrievals to identify the anomalous humidity distributions in the lower troposphere, but underscore the need for suitable vertical resolution in the first-guess profile used in the retrievals under such conditions.

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Köhn, Eike E., Sören Thomsen, Damian L. Arévalo-Martínez y Torsten Kanzow. "Submesoscale CO2 variability across an upwelling front off Peru". Ocean Science 13, n.º 6 (4 de diciembre de 2017): 1017–33. http://dx.doi.org/10.5194/os-13-1017-2017.

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Abstract. As a major source for atmospheric CO2, the Peruvian upwelling region exhibits strong variability in surface fCO2 on short spatial and temporal scales. Understanding the physical processes driving the strong variability is of fundamental importance for constraining the effect of marine emissions from upwelling regions on the global CO2 budget. In this study, a frontal decay on length scales of 𝒪(10 km) was observed off the Peruvian coast following a pronounced decrease in down-frontal (equatorward) wind speed with a time lag of 9 h. Simultaneously, the sea-to-air flux of CO2 on the inshore (cold) side of the front dropped from up to 80 to 10 mmol m−2 day−1, while the offshore (warm) side of the front was constantly outgassing at a rate of 10–20 mmol m−2 day−1. Based on repeated ship transects the decay of the front was observed to occur in two phases. The first phase was characterized by a development of coherent surface temperature anomalies which gained in amplitude over 6–9 h. The second phase was characterized by a disappearance of the surface temperature front within 6 h. Submesoscale mixed-layer instabilities were present but seem too slow to completely remove the temperature gradient in this short time period. Dynamics such as a pressure-driven gravity current appear to be a likely mechanism behind the evolution of the front.

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26

Wiacek, Aldona, Li Li, Keane Tobin y Morgan Mitchell. "Characterization of trace gas emissions at an intermediate port". Atmospheric Chemistry and Physics 18, n.º 19 (1 de octubre de 2018): 13787–812. http://dx.doi.org/10.5194/acp-18-13787-2018.

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Abstract. Growing ship traffic in Atlantic Canada strengthens the local economy but also plays an important role in greenhouse gas and air pollutant emissions in this coastal environment. A mobile open-path Fourier transform infrared (OP-FTIR; acronyms defined in Appendix A) spectrometer was set up in Halifax Harbour (Nova Scotia, Canada), an intermediate harbour integrated into the downtown core, to measure trace gas concentrations in the vicinity of marine vessels, in some cases with direct or near-direct marine combustion plume intercepts. This is the first application of the OP-FTIR measurement technique to real-time, spectroscopic measurements of CO2, CO, O3, NO2, NH3, CH3OH, HCHO, CH4 and N2O in the vicinity of harbour emissions originating from a variety of marine vessels, and the first measurement of shipping emissions in the ambient environment along the eastern seaboard of North America outside of the Gulf Coast. The spectrometer, its active mid-IR source and its detector were located on shore while the passive retroreflector was on a nearby island, yielding a 455 m open path over the ocean (910 m two-way). Atmospheric absorption spectra were recorded during day, night, sunny, cloudy and substantially foggy or precipitating conditions, with a temporal resolution of 1 min or better. A weather station was co-located with the retroreflector to aid in the processing of absorption spectra and the interpretation of results, while a webcam recorded images of the harbour once per minute. Trace gas concentrations were retrieved from spectra by the MALT non-linear least squares iterative fitting routine. During field measurements (7 days in July–August 2016; 12 days in January 2017) AIS information on nearby ship activity was manually collected from a commercial website and used to calculate emission rates of shipping combustion products (CO2, CO, NOx, HC, SO2), which were then linked to measured concentration variations using ship position and wind information. During periods of low wind speed we observed extended (∼9 h) emission accumulations combined with near-complete O3 titration, both in winter and in summer. Our results compare well with a NAPS monitoring station ∼1 km away, pointing to the extended spatial scale of this effect, commonly found in much larger European shipping channels. We calculated total marine sector emissions in Halifax Harbour based on a complete AIS dataset of ship activity during the cruise ship season (May–October 2015) and the remainder of the year (November 2015–April 2016) and found trace gas emissions (tonnes) to be 2.8 % higher on average during the cruise ship season, when passenger ship emissions were found to contribute 18 % of emitted CO2, CO, NOx, SO2 and HC (0.5 % in the off season due to occasional cruise ships arriving, even in April). Similarly, calculated particulate emissions are 4.1 % higher during the cruise ship season, when passenger ship emissions contribute 18 % of the emitted particulate matter (PM) (0.5 % in the off season). Tugs were found to make the biggest contribution to harbour emissions of trace gases in both cruise ship season (23 % NOx, 24 % SO2) and the off season (26 % of both SO2 and NOx), followed by container ships (25 % NOx and SO2 in the off season, 21 % NOx and SO2 in cruise ship season). In the cruise ship season cruise ships were observed to be in third place regarding trace gas emissions, whilst tankers were in third place in the off season, with both being responsible for 18 % of the calculated emissions. While the concentrations of all regulated trace gases measured by OP-FTIR as well as the nearby in situ NAPS sensors were well below maximum hourly permissible levels at all times during the 19-day measurement period, we find that AIS-based shipping emissions of NOx over the course of 1 year are 4.2 times greater than those of a nearby 500 MW stationary source emitter and greater than or comparable to all vehicle NOx emissions in the city. Our findings highlight the need to accurately represent emissions from the shipping and marine sectors at intermediate ports integrated into urban environments. Emissions can be represented as pseudo-stationary and/or pseudo-line sources.

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Lucas, Emeritus J. "Signal transmission through seawater for MHz frequencies and medium distances (0–30 m) using ionic current waves". Underwater Technology 36, n.º 3 (27 de noviembre de 2019): 53–61. http://dx.doi.org/10.3723/ut.36.053.

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Electromagnetic (EM) signals can only be transmitted through seawater for short distances (<1 m) for frequencies (>1 MHz). Therefore a new technique, the ionic current wave (ICW), has been developed for signal propagation at MHz frequency. This technique uses the conduction current produced in seawater as a result of thermal ionisation releasing H+ and OH– ions. A small voltage (<1.5 V pk) is applied between two metal electrodes submerged in the seawater to avoid ionisation by the input electrical energy. A detailed theoretical analysis of the ICW process has shown that ionic currents can be transmitted at MHz frequency over distances of 10 m with low signal loss per decade. For longer propagation distances of 100 m the theory predicts a signal loss of –20 dB per decade. Propagation experiments have been carried out in Liverpool dock seawater for distances of 2 m–28 m between parallel 0.5 m × 0.3 m electrodes placed vertically in the seawater at a depth of 2 m. Signal frequencies within the range of 1 MHz–8 MHz have been investigated. In each experiment the received propa gated signal power was approximately –67 dBm (well above the dock electrical noise of –140 dBm) and only showed a small power loss over the full range of propagation. The ICW system will be able to measure longer propagation distances in deep seawater conditions suitable for ship and submarine communications. Its performance is comparable to that of sonar systems.

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Banta, Robert M., Yelena L. Pichugina, W. Alan Brewer, Eric P. James, Joseph B. Olson, Stanley G. Benjamin, Jacob R. Carley et al. "Evaluating and Improving NWP Forecast Models for the Future: How the Needs of Offshore Wind Energy Can Point the Way". Bulletin of the American Meteorological Society 99, n.º 6 (junio de 2018): 1155–76. http://dx.doi.org/10.1175/bams-d-16-0310.1.

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AbstractTo advance the understanding of meteorological processes in offshore coastal regions, the spatial variability of wind profiles must be characterized and uncertainties (errors) in NWP model wind forecasts quantified. These gaps are especially critical for the new offshore wind energy industry, where wind profile measurements in the marine atmospheric layer spanned by wind turbine rotor blades, generally 50–200 m above mean sea level (MSL), have been largely unavailable. Here, high-quality wind profile measurements were available every 15 min from the National Oceanic and Atmospheric Administration/Earth System Research Laboratory (NOAA/ESRL)’s high-resolution Doppler lidar (HRDL) during a monthlong research cruise in the Gulf of Maine for the 2004 New England Air Quality Study. These measurements were compared with retrospective NWP model wind forecasts over the area using two NOAA forecast-modeling systems [North American Mesoscale Forecast System (NAM) and Rapid Refresh (RAP)]. HRDL profile measurements quantified model errors, including their dependence on height above sea level, diurnal cycle, and forecast lead time. Typical model wind speed errors were ∼2.5 m s−1, and vector-wind errors were ∼4 m s−1. Short-term forecast errors were larger near the surface—30% larger below 100 m than above and largest for several hours after local midnight (biased low). Longer-term, 12-h forecasts had the largest errors after local sunset (biased high). At more than 3-h lead times, predictions from finer-resolution models exhibited larger errors. Horizontal variability of winds, measured as the ship traversed the Gulf of Maine, was significant and raised questions about whether modeled fields, which appeared smooth in comparison, were capturing this variability. If not, horizontal arrays of high-quality, vertical-profiling devices will be required for wind energy resource assessment offshore. Such measurement arrays are also needed to improve NWP models.

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Rutkowski, Lucile, Alexandra C. Johansson, Damir Valiev, Amir Khodabakhsh, Arkadiusz Tkacz, Florian M. Schmidt y Aleksandra Foltynowicz. "Detection of OH in an atmospheric flame at 1.5 um using optical frequency comb spectroscopy". Photonics Letters of Poland 8, n.º 4 (31 de diciembre de 2016): 110. http://dx.doi.org/10.4302/plp.2016.4.07.

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We report broadband detection of OH in a premixed CH4/air flat flame at atmospheric pressure using cavity-enhanced absorption spectroscopy based on an Er:fiber femtosecond laserand a Fourier transform spectrometer.By taking ratios of spectra measured at different heights above the burner we separate twenty OH transitions from the largely overlapping water background. Weretrieve from fits to the OH lines the relative variation of the OH concentration and flame temperature with height above the burner and compare them with 1-D simulations of the flamestructure. Full Text: PDF ReferencesG. Meijer, M. G. Boogaarts, R. T. Jongma, D. H. Parker and A. M. Wodtke, "Coherent cavity ring down spectroscopy", Chem. Phys. Lett. 217, 1, 112 (1994). CrossRef S. Cheskis, I. Derzy, V. A. Lozovsky, A. Kachanov and D. Romanini, "Cavity ring-down spectroscopy of OH radicals in low pressure flame", Appl. Phys. B 66, 3, 377 (1998). CrossRef X. Mercier, E. Therssen, J. F. Pauwels and P. Desgroux, "Cavity ring-down measurements of OH radical in atmospheric premixed and diffusion flames.: A comparison with laser-induced fluorescence and direct laser absorption", Chem. Phys. Lett. 299, 1, 75 (1999). CrossRef J. Scherer, D. Voelkel and D. Rakestraw, "Infrared cavity ringdown laser absorption spectroscopy (IR-CRLAS) in low pressure flames", Appl. Phys. B 64, 6, 699 (1997). CrossRef R. Peeters, G. Berden and G. Meijer, "Near-infrared cavity enhanced absorption spectroscopy of hot water and OH in an oven and in flames", Appl. Phys. B 73, 1, 65 (2001). CrossRef T. Aizawa, "Diode-laser wavelength-modulation absorption spectroscopy for quantitative in situ measurements of temperature and OH radical concentration in combustion gases", Appl. Opt. 40, 27, 4894 (2001). CrossRef B. Löhden, S. Kuznetsova, K. Sengstock, V. M. Baev, et al., "Fiber laser intracavity absorption spectroscopy for in situ multicomponent gas analysis in the atmosphere and combustion environments", Appl. Phys. B 102, 2, 331 (2011). CrossRef A. Matynia, M. Idir, J. Molet, C. Roche, et al., "Absolute OH concentration profiles measurements in high pressure counterflow flames by coupling LIF, PLIF, and absorption techniques", Appl. Phys. B 108, 2, 393 (2012). CrossRef R. S. Watt, T. Laurila, C. F. Kaminski and J. Hult, "Cavity Enhanced Spectroscopy of High-Temperature H2O in the Near-Infrared Using a Supercontinuum Light Source", Appl. Spectrosc. 63, 12, 1389 (2009). CrossRef C. Abd Alrahman, A. Khodabakhsh, F. M. Schmidt, Z. Qu and A. Foltynowicz, "Cavity-enhanced optical frequency comb spectroscopy of high-temperature H2O in a flame", Opt. Express 22, 11, 13889 (2014). CrossRef A. Foltynowicz, P. Maslowski, A. J. Fleisher, B. J. Bjork and J. Ye, "Cavity-enhanced optical frequency comb spectroscopy in the mid-infrared application to trace detection of hydrogen peroxide", Appl. Phys. B 110, 2, 163 (2013). CrossRef Z. Qu, R. Ghorbani, D. Valiev and F. M. Schmidt, "Calibration-free scanned wavelength modulation spectroscopy ? application to H2O and temperature sensing in flames", Opt. Express 23, 12, 16492 (2015). CrossRef L. Rutkowski, A. Khodabakhsh, A. C. Johansson, D. M. Valiev, et al., "Measurement of H2O and OH in a Flame by Optical Frequency Comb Spectroscopy", CLEO: Science and Innovations SW4H.8 (2016). CrossRef L. S. Rothman, I. E. Gordon, Y. Babikov, A. Barbe, et al., "The HITRAN2012 molecular spectroscopic database", J. Quant. Spectrosc. Radiat. Transf. 130, 4 (2013). CrossRef

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Каунг, М. С. "Effect of airfoil thickness on cargo carrying capacity for high speed ship with aerodynamic unloading". MORSKIE INTELLEKTUAL`NYE TEHNOLOGII), n.º 2(52) (20 de junio de 2021): 53–57. http://dx.doi.org/10.37220/mit.2021.52.2.034.

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В последние несколько лет, высокоскоростные суда с аэродинамической разгрузкой вызывают интерес, как в гражданском, так и военно-морском транспорте. Было проведено много исследований аэродинамических профилей около границы раздела. Но исследований грузоподъемности крыла для этого типа судов было мало. В данной работе численно оценивалось влияние толщины профиля на грузоподъемность высокоскоростного суда с аэродинамической разгрузкой. Для изучения влияния толщины аэродинамического профиля в диапазоне от 10% до 60% хорды, были проведены расчеты на движущемся экране при углах атаки от 0° до 8° и (h/c = 0,1). Все аэродинамические профили имели хорду 1 м. Профили были модифицированы и имели плоскую нижнюю поверхность, чтобы избежать присасывания на малых углах атаки при малом отстоянии от границы раздела. Поскольку это является нежелательным явлением. Модель турбулентности k-ω SST использовалась для моделирования обтекания крыла при числах Рейнольдса (R_e = 〖1×10〗^6). Для проверки результатов расчетов результаты CFD профиля NACA 4412 при движении над землей были сопоставлены с экспериментальными данными. В данной статье показано, какой тип толщины крылового профиля следует использовать для получения эффективной грузоподъемности высокоскоростного суда с аэродинамической разгрузкой при его проектировании. In the past few years, high-speed aerodynamic unloading vessels have attracted interest in both civilian and naval transport. There have been many studies of airfoils near the interface. But there has been little research on wing loading for this type of vessel. In this study, the effect of the profile thickness on the carrying capacity of a high-speed vehicle with aerodynamic unloading was numerically estimated. To study the effect of the thickness of the airfoil in the range from 10% to 60% of the chord, calculations were carried out on a moving screen at angles of attack from 0 ° to 8 ° and (h / c = 0.1). All airfoils had a chord of 1 m. The airfoils were modified to have a flat bottom surface to avoid suction at low angles of attack with a small distance from the interface. As this is an undesirable phenomenon. The k-ω SST turbulence model was used to simulate the flow around the wing at Reynolds numbers (R_e = 〖1×10〗^6). To check the calculation results, the CFD results of the NACA 4412 profile when moving above the ground were compared with the experimental data. This article shows what type of airfoil thickness should be used to obtain the effective carrying capacity of a high-speed aerodynamic craft in its design.

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31

Branch, R., A. T. Jessup, P. J. Minnett y E. L. Key. "Comparisons of Shipboard Infrared Sea Surface Skin Temperature Measurements from the CIRIMS and the M-AERI". Journal of Atmospheric and Oceanic Technology 25, n.º 4 (1 de abril de 2008): 598–606. http://dx.doi.org/10.1175/2007jtecho480.1.

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Abstract Extensive comparisons are made of the infrared sea surface skin temperature Tskin measured by the Calibrated Infrared In situ Measurement System (CIRIMS) and the Marine-Atmospheric Emitted Radiance Interferometer (M-AERI). Data were collected from four separate deployments on the NOAA research vessel (R/V) Ronald H. Brown and the U.S. Coast Guard (USCG) Polar Sea over a wide range of latitudes and environmental conditions. The deployment time totaled roughly 6 months over a 4-yr period and resulted in over 7000 comparison values. The mean offset between the two instruments showed that CIRIMS consistently measured a lower temperature than the M-AERI, but by less than 0.10°C. This mean offset was found to be dependent upon sky condition, wind speed, and ship roll, which implies the offset is likely due to uncertainty in the emissivity. The CIRIMS Tskin was recomputed using two alterative emissivity values, one based on emissivity measured by the M-AERI and the other based on a wind-speed-dependent model. In both cases, the recomputation of the CIRIMS Tskin significantly reduced the mean offset. The overall standard deviation between the M-AERI and CIRIMS Tskin was 0.16°C, did not significantly depend on environmental conditions, and was within the expected values of instrument and comparison uncertainties. These comparisons demonstrate the success of CIRIMS in achieving good agreement with the M-AERI over a wide range of conditions. The results also highlight the importance of the sea surface emissivity when measuring the ocean surface skin temperature.

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32

Heringa, M. F., P. F. DeCarlo, R. Chirico, T. Tritscher, M. Clairotte, C. Mohr, M. Crippa et al. "A new method to discriminate secondary organic aerosols from different sources using high-resolution aerosol mass spectra". Atmospheric Chemistry and Physics Discussions 11, n.º 10 (27 de octubre de 2011): 29055–91. http://dx.doi.org/10.5194/acpd-11-29055-2011.

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Abstract. Organic aerosol (OA) represents a significant and often major fraction of the non-refractory PM1 (particulate matter with an aerodynamic diameter da < 1 μm) mass. Secondary organic aerosol (SOA) is an important contributor to the OA and can be formed from biogenic and anthropogenic precursors. Here we present results from the characterization of SOA produced from the emissions of three different anthropogenic sources. SOA from a log wood burner, a Euro 2 diesel car and a two-stroke Euro 2 scooter were characterized with an Aerodyne high-resolution time-of-flight aerosol mass spectrometer (HR-TOF-AMS) and compared to SOA from α-pinene. The emissions were sampled from the chimney/tailpipe by a heated inlet system and filtered before injection into a smog chamber. The gas phase emissions were irradiated by xenon arc lamps to initiate photo-chemistry which led to nucleation and subsequent particle growth by SOA production. Duplicate experiments were performed for each SOA type, with the averaged organic mass spectra in the m/z range 12–250 showing Pearson's r values >0.94 for the correlations between the different SOA types after 5 h of aging. High-resolution mass spectra (HR-MS) showed that the dominant peaks in the MS, m/z 43 and 44, are dominated by the oxygenated ions C2H3O+ and CO2+, respectively, similarly to the relatively fresh semi-volatile oxidized OA (SV-OOA) observed in the ambient aerosol. The atomic O : C ratios were found to be in the range of 0.25–0.55 with no major increase during the first 5 h of aging. On average, the diesel SOA showed the lowest O : C ratio followed by SOA from wood burning, α-pinene and the scooter emissions. Grouping the fragment ions based on their carbon number revealed that the SOA source with the highest O : C ratio had the largest fraction of small ions. Fragment ions containing up to 3 carbon atoms accounted for 66%, 68%, 72% and 76% of the organic spectrum of the SOA produced by the diesel car, wood burner, α-pinene and the scooter, respectively. The HR data of the four sources could be clustered and separated using principal component analysis (PCA). The model showed a significant separation of the four SOA types and clustering of the duplicate experiments on the first two principal components (PCs), which explained 79% of the total variance. Projection of ambient SV-OOA spectra resolved by positive matrix factorization (PMF) showed that this approach could be useful to identify large contributions of the tested SOA sources to SV-OOA. The first results from this study indicate that the SV-OOA in Barcelona is strongly influenced by diesel emissions in winter while in summer at SIRTA at the southwestern edge of Paris SV-OOA is more similar to alpha-pinene SOA. However, contributions to the ambient SV-OOA from SOA sources that are not covered by the model can cause major interference and therefore future expansions of the PCA model with additional SOA sources is recommended.

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33

Bai, Shubin, Yuanqiao Wen, Li He, Yiming Liu, Yan Zhang, Qi Yu y Weichun Ma. "Single-Vessel Plume Dispersion Simulation: Method and a Case Study Using CALPUFF in the Yantian Port Area, Shenzhen (China)". International Journal of Environmental Research and Public Health 17, n.º 21 (26 de octubre de 2020): 7831. http://dx.doi.org/10.3390/ijerph17217831.

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To study the impact of vessel pollution on the atmospheric environment of the surrounding area, we present a numerical simulation method based on regional emissions inventories. The general spatial resolution is ≥1 km and the temporal resolution is ≥1 h; parameters which are suitable for the study of larger space–time scales. In this paper, the WRF/CALMET/CALPUFF model and Automatic Identification System (AIS) data are employed to develop a single-vessel atmospheric pollution diffusion model. The goal of this research uses existing meteorological models and diffusion models to provide a simulation technology method for studying the diffusion of SO2 from a single ship. We take the outgoing phase of ocean-going container vessels in Yantian Port as an example. It can be used to set the position of sensitive receptors near the port area. Simulations are implemented with CALPUFF and the results are compared with data derived from on-site monitoring instrument. The CALPUFF modelling domain covers an area of 925 km2 with a grid spacing of 500 m. The simulation results demonstrated agreement with the measured data. The ground concentration contribution value ranged from 10 to 102 μg/m3, while the affected area was about 4–26 km2 and the high-value area of the ground concentration contribution was distributed within 1–2 km from the ship track. Emissions generated by the vessels represent a considerable contribution to SO2 pollution around the harbor areas.

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34

Shroyer, E. L., J. N. Moum y J. D. Nash. "Energy transformations and dissipation of nonlinear internal waves over New Jersey's continental shelf". Nonlinear Processes in Geophysics 17, n.º 4 (3 de agosto de 2010): 345–60. http://dx.doi.org/10.5194/npg-17-345-2010.

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Abstract. The energetics of large amplitude, high-frequency nonlinear internal waves (NLIWs) observed over the New Jersey continental shelf are summarized from ship and mooring data acquired in August 2006. NLIW energy was typically on the order of 105 Jm−1, and the wave dissipative loss was near 50 W m−1. However, wave energies (dissipations) were ~10 (~2) times greater than these values during a particular week-long period. In general, the leading waves in a packet grew in energy across the outer shelf, reached peak values near 40 km inshore of the shelf break, and then lost energy to turbulent mixing. Wave growth was attributed to the bore-like nature of the internal tide, as wave groups that exhibited larger long-term (lasting for a few hours) displacements of the pycnocline offshore typically had greater energy inshore. For ship-observed NLIWs, the average dissipative loss over the region of decay scaled with the peak energy in waves; extending this scaling to mooring data produces estimates of NLIW dissipative loss consistent with those made using the flux divergence of wave energy. The decay time scale of the NLIWs was approximately 12 h corresponding to a length scale of 35 km (O(100) wavelengths). Imposed on these larger scale energetic trends, were short, rapid exchanges associated with wave interactions and shoaling on a localized topographic rise. Both of these events resulted in the onset of shear instabilities and large energy loss to turbulent mixing.

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35

Anggela, Wela Celsi. "Peranan Etnis Tionghoa Muslim Pada Masa Kolonial Belanda, Abad ke-19 di Palembang". Journal of Islamic History 1, n.º 1 (15 de junio de 2021): 66–77. http://dx.doi.org/10.53088/jih.v1i1.101.

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This Study describes the historical series of the role of the Chinese Muslim etnich group in the 19th century Dutch colonial period in Palembang, in this article will reveal several Chinese Muslim ethnich figures and clerics who played a role in the 19th century Dutch colonial period in Palembang, including; Kiyai Mas Husin (Yu-Chien), Baba Yu Chien has a son named Muhammad Najib I who holds the title of Kiyai Demang Jayosepuh Wiraguno who served as a minister during the reign of Sultan Ahmad Najamuddin, Baba Balqiyah and Baba Mas’ud, they played a role in resisting the Dutch colonial and drowning Dutch cruise ship at the mouth of the Ogan river in Palembang. After they died, his role was replaced by Baba Muhammad Najib II or Kiyai Demang Jayalaksana who was an important figure in the construction of the Great Mosque of Palembang in the reign of Sultan Muhammad Badaruddin II (1724 M/1137 H). The majority are Muslims from the Dutch colonial nation.

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36

Brümmer, Burghard, Gerd Müller y Gunnar Noer. "A Polar Low Pair over the Norwegian Sea". Monthly Weather Review 137, n.º 8 (1 de agosto de 2009): 2559–75. http://dx.doi.org/10.1175/2009mwr2864.1.

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Abstract During the Lofotes cyclone experiment (LOFZY 2005), two polar lows developed one behind the other inside a cold-air outbreak from the north in the lee of Spitsbergen on 7 March 2005. Buoys, ship, and aircraft measurements as well as satellite imagery are applied to analyze the polar low bulk properties, the horizontal and vertical structure, and the mass, moisture, and heat budget. The lifetime of the system until landfall at northern Norway was 12 h. The generation occurred under the left exit region of an upper-level jet with 70 m s−1. Both polar lows had a radius of 100–130 km and extended to a height of about 2.5 km. The propagation speeds were within 14–17 m s−1 and correspond to the vertically averaged wind velocity of the lowest 2.5 km. In the polar low centers the pressure was about 2–3 hPa lower and the air was 1–2 K warmer and drier than in the surroundings. Aircraft measurements in the second of the two polar lows show an embedded frontlike precipitation band north of the center. Here, the highest low-level winds with 25 m s−1 and the largest fluxes of sensible and latent heat with 290 and 520 W m−2, respectively, were measured (areal averages amounted to 115 and 190 W m−2). Aircraft data show mass convergence in the subcloud layer (0–900 m) and divergence in the cloud layer (900–2500 m). Moisture supply by evaporation from the sea surface was about twice as large as that by convergence in the subcloud layer. The condensation rate in the cloud layer nearly equaled the rate of evaporation at the sea surface. Almost all condensed cloud water was converted to precipitation water. Only half of the precipitation at the cloud base reached the sea surface.

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37

Messerle, V. E., A. B. Ustimenko y K. A. Umbetkaliev. "Plasma ignition of dust-coal flame". Горение и Плазмохимия 17, n.º 1 (8 de enero de 2019): 14–22. http://dx.doi.org/10.18321/cpc285.

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One of the promising power engineering technologies is the plasma thermochemical preparation of pulverized coal to burning using plasma-fuel systems (PFS). This technology allows increasing the efficiency of fuel use and environmental indicators of thermal power plants, as well as eliminating the use of fuel oil, traditionally used to start-up the boilers and stabilize the combustion of a pulverized coal flame. This paper presents the results of numerical experiments on ignition of pulverized coal in PFS. PFS is designed for fuel oil-free start-up of the boilers and stabilization of pulverized coal flame, and represents a pulverized coal burner equipped with plasma torch. Via PlasmaKinTherm software which combines kinetic and thermodynamic methods of calculating the processes of motion, heating, thermochemical transformations and fuel mixture ignition in the volume of PFS, impact of the power of the plasma torch and ash content of coal onto efficiency of fuel mixture ignition have been determined. Also one of the main regime parameters of PFS providing ignition of the fuel is concentration of coal dust in the fuel mixture which can vary within a wide range. Therefore, conditions for fuel mixture ignition in PFS have been investigated, depending on the concentration of coal in the fuel mixture in the range from 0.4 to 1.8 kg of coal per 1 kg of air. Calculations were performed for cylindrical PFS of 0.2 m diameter and 2 m of length at fixed consumption of coal (1000 kg/h) and the plasma torch power (60 kW) for three values of coal ash content (20, 40 and 70%). The basic regularities of the process of plasma thermochemical preparation of fuel for burning were revealed.

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38

Taymarov, M. A., V. K. Ilyin, E. G. Chiklyaev y R. G. Sungatullin. "Features of application of the methane-hydrogen fraction as fuel for thermal power plant boiler". Power engineering: research, equipment, technology 21, n.º 3 (29 de noviembre de 2019): 109–16. http://dx.doi.org/10.30724/1998-9903-2019-21-3-109-116.

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The methane-hydrogen fraction is a gaseous hydrocarbon by-product during oil processing for obtaining petroleum products. Until recently, the methane-hydrogen fraction was used as furnace oil in internal technological processes at a refinery. Some of the low-calorie methane-hydrogen fraction was burned in flares. Driven by the prospect of the methane-hydrogen fraction use as a fuel alternative to natural gas for burning in thermal power plants boilers, it became necessary to study the methane-hydrogen fraction combustion processes in large volumes. The conversion of ON-1000/1 and ON-1000/2 furnaces from the combustion of the methane- hydrogen fraction with combustion heat of 25.45 MJ/m3 to the combustion of the composition with combustion heat of 18.8 MJ/m3 leads to a decrease in temperature in the flame core for 100 °C as an average. The intensity of flame radiation on the radiant tubes decreases. Therefore, the operation of furnaces during combustion of methane-hydrogen fraction with a low heat of combustion at the gas oil hydro-treating unit is carried out only with a fresh catalyst, which allows lower flame temperatures in the burner.The experiments to determine the concentration of nitrogen oxides NOx and the burning rate w of the methane-hydrogen fraction in the ON-1000/1 furnace and natural gas in the TGM-84A boiler, depending upon the heat of combustion Qnr were carried out. The obtained results showed that the increase in the hydrogen content Н2 from 10.05 % to 18.36% (by mass) results in an increase in the burning rate w by 45%. The burning rate of natural gas with methane CH4 content of 98.89% in the TGM-84A boiler is 0.84 m/s, i.e. it is 2.5 times lower than the burning rate of the methane- hydrogen fraction with H2 content of 10.05%. The distributions of heat flux from the flame qf over the burner height h in the TGM-84A boiler were obtained in case of natural gas burning and calculation of burning of the methane-hydrogen fraction with a hydrogen content of 10.05% and methane of 28.27%. The comparison of the obtained data shows that burning of methane- hydrogen fraction causes an increase in the incident heat flux qf at the outlet of the burner.

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39

Hedgecock, I. M., C. N. Gencarelli, G. J. Sch{ü}rmann, F. Sprovieri y N. Pirrone. "Measurements and modelling of ozone in the Mediterranean MBL: an investigation of the importance of ship emissions to local ozone production". Atmospheric Chemistry and Physics Discussions 12, n.º 7 (5 de julio de 2012): 16557–602. http://dx.doi.org/10.5194/acpd-12-16557-2012.

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Abstract. Elevated concentrations of ground level ozone are both hazardous to human health and detrimental to agricultural production. The Mediterranean Basin, due to its position under the descending branch of the Hadley Cell circulation during the summer months, enjoys periods of stable, sunny and warm weather which provide ideal conditions for the production of ozone. The presence of major population centres and numerous industrialised areas in the coastal zone result in both a continual supply of ozone precursor compounds and also a significant number of people to suffer the consequences of high ozone concentrations. Using the WRF/Chem model validated with data obtained from seven oceanographic measurement campaigns, performed between 2000 and 2010, aboard the Italian Research Council's R. V. Urania, and also from a number of EMEP monitoring stations located around the Mediterranean Basin, the importance of emissions from maritime traffic in the region has been investigated. The model results indicate that over large areas of the Mediterranean emissions from shipping contribute between 5 and 10 ppb to the ground level O3 daily average concentration during the summer. The contribution to the hourly average O3 is up to 40 ppb in some particularly busy shipping lanes. Importantly the results suggest that in a number of coastal areas the contribution from ship emissions to the local O3 concentration can make the difference between complying with the EU Air Quality standard of a maximum 8 h mean of 120 μg m−3 and exceeding it.

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40

Kannan, R., M. C. Sanjana y G. Latha. "Passive Acoustic Recognition of Fishing Vessel Activity in the Shallow Waters of the Arabian Sea: A Statistical Approach". Fluctuation and Noise Letters 14, n.º 04 (9 de noviembre de 2015): 1550035. http://dx.doi.org/10.1142/s0219477515500352.

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The ambient noise system consisting of a vertical linear hydrophone array (VLA) with 12 elements was deployed in the waters of the Arabian Sea at a depth of 16[Formula: see text]m, off Goa, India, for extracting the ambient noise during the fishing season (March, April and May, 2013 before the onset of the south west monsoon). This study focuses on fishing vessel activity by finding the domination of the vessel and wind noise at two 12 hourly periodic cycles that start at midnight and noon, using the statistical analysis. It is performed using statistical parameters, like the mean, median, and standard deviation, skewness, percentile and spread of data. It is observed that the vessel noise dominates during the 12[Formula: see text]h period that starts at midnight and is an indication of the activity of fishing vessels while the wind generated noise is more during the 12[Formula: see text]h period that starts at noon, which is a sign of the domination of the sea breeze effects. This is the first time that a statistical analysis has been carried out to study the ambient noise data collected off Goa, in order to find the fishing vessel activity during the pre-monsoon season. The results are verified with the fishing information from the Directorate of Fisheries, Goa, ship traffic data from the Mormugao Port Trust and wind speed measurements.

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41

Orheim, Olav. "Antarctic Icebergs – Production, Distribution and Disintegration (Abstract)". Annals of Glaciology 11 (1988): 205. http://dx.doi.org/10.1017/s0260305500006649.

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A programme of systematic iceberg observations was initiated in 1981 by Norsk Polarinstitutt through the SCAR Working Group on Glaciology. Icebergs are recorded every 6 h and in five length groups: 10-50, 50-200, 200-500 and 500-1000 m, and those over 1000 m, which are described individually. Data on more than 100 000 icebergs are now on file at Norsk Polarinstitutt, and practically all ships travelling to and from Antarctica participate in the collection of data. This paper presents the first comprehensive analysis of the iceberg data. The quality of the data set is discussed, with consideration of potential errors in and limitations of the data, and various statistical evaluations. Representative distribution data are presented, and used to determine iceberg production, disintegration and mean residence times, and regional and total Antarctic calving rates. The incidence of large-scale calving in particular is evaluated, including the remarkably large break-offs in recent years. These exceed both the total annual accumulation on the Antarctic continent and the mean annual calving rate as determined from ship observations. The results show further: (1) that there are more than 200 000 icebergs south of the Antarctic Convergence, (2) that there are large regional differences in iceberg calving rates and iceberg sizes, and (3) that the calving rate from Antarctica is higher than that given in most previous estimates, which implies (4) that the mass balance of the Antarctic ice sheet is not positive as suggested by most recent estimates.

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42

Orheim, Olav. "Antarctic Icebergs – Production, Distribution and Disintegration (Abstract)". Annals of Glaciology 11 (1988): 205. http://dx.doi.org/10.3189/s0260305500006649.

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A programme of systematic iceberg observations was initiated in 1981 by Norsk Polarinstitutt through the SCAR Working Group on Glaciology. Icebergs are recorded every 6 h and in five length groups: 10-50, 50-200, 200-500 and 500-1000 m, and those over 1000 m, which are described individually. Data on more than 100 000 icebergs are now on file at Norsk Polarinstitutt, and practically all ships travelling to and from Antarctica participate in the collection of data.This paper presents the first comprehensive analysis of the iceberg data. The quality of the data set is discussed, with consideration of potential errors in and limitations of the data, and various statistical evaluations. Representative distribution data are presented, and used to determine iceberg production, disintegration and mean residence times, and regional and total Antarctic calving rates.The incidence of large-scale calving in particular is evaluated, including the remarkably large break-offs in recent years. These exceed both the total annual accumulation on the Antarctic continent and the mean annual calving rate as determined from ship observations.The results show further: (1) that there are more than 200 000 icebergs south of the Antarctic Convergence, (2) that there are large regional differences in iceberg calving rates and iceberg sizes, and (3) that the calving rate from Antarctica is higher than that given in most previous estimates, which implies (4) that the mass balance of the Antarctic ice sheet is not positive as suggested by most recent estimates.

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43

Zou, Chang Ping y Jian Qiong Feng. "Innovation of the Advanced Actuator". Applied Mechanics and Materials 249-250 (diciembre de 2012): 382–85. http://dx.doi.org/10.4028/www.scientific.net/amm.249-250.382.

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Actuator is a kind of swaying mechanism whose power source is the hydraulic pressure oil, which may be widely applied to varied occasions where need swaying mechanisms, such as aircraft, tank, ship, train, etc. An aircraft needed a most advanced actuator which can produce torque up to 28kg•m with its unit weight, and set strict demands on such indexes as weight, dimension. According to existing plan, an actuator was designed and manufactured, being far inferior to requirement, which adopted a complex gear train composed of 2K-H and 3K planetary reductors. On the basis of analyzing existing dozens of reductors, a new structure that achieves swaying with multi-start ball guide screw driven by reciprocating piston rod of high-pressure oil cylinder was put forward. Having analyzed and compared more than ten new type of plans, a structural model of straight-rotary ball pair was proposed, an ideal plan of identical radius ball-return was found, a new spatial tight ball-return curve was designed, and the optimal design of the advanced actuator was finished. Computer simulation and prototype experiment made clear that each index of the advanced actuator could satisfy the aircraft’s demand.

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44

Gow, Paul A. y John W. Waterhouse. "Renovation of the Floating White House". Marine Technology and SNAME News 24, n.º 03 (1 de julio de 1987): 212–19. http://dx.doi.org/10.5957/mt1.1987.24.3.212.

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Built in 1934 as a cutter for the U.S. Coast Guard, the Potomac achieved its notoriety while serving for ten years as a yacht for the President of the United States, Franklin D. Roosevelt. Through 50 years of changing technology, marine regulations, and fashion, this 165-ft (50.30 m) vessel has made its sometimes halting way, escaping the scrapping yard, and is today sitting in Oakland, California awaiting renovation. The goal of the owner, the Port of Oakland, is to use the Potomac as a floating museum carrying passengers on an excursion into the late 1930's. In the fall of 1984 the Association for the Preservation of the Presidential Yacht Potomac (APPYP), managers of the Potomac, contracted with Nickum & Spaulding Associates, Inc. (N&SA) for engineering services. N&SA was to generate a shipyard bid package that would produce a restored vessel acceptable to the U.S. Coast Guard as a Subchapter H passenger ship. This paper reviews the vessel's history and examines some of the design compromises necessary to make the Potomac as historically accurate as possible while meeting the current marine regulations and museum function requirements.

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45

Taccani, Rodolfo, Gabriele Maggiore y Diego Micheli. "Development of a Process Simulation Model for the Analysis of the Loading and Unloading System of a CNG Carrier Equipped with Novel Lightweight Pressure Cylinders". Applied Sciences 10, n.º 21 (27 de octubre de 2020): 7555. http://dx.doi.org/10.3390/app10217555.

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Natural gas is becoming increasingly important to meet the growing demand for energy, guaranteeing a reduction in polluting emissions. Transportation in form of Compressed Natural Gas (CNG) could be an alternative to the traditional transportation by pipeline or, as liquefied gas, by ships, but the ratio between the mass of transported gas and the container weight is currently too low. One of the many projects focusing on the development of innovative lightweight pressure cylinders is GASVESSEL, which proposes composite cylinders with a diameter of more than 3 m: loaded on a ship, they could allow transporting quantities of CNG as big as 10,000 tons. The related loading and unloading processes affect both the overall time required for transport and the quantity of transported gas; therefore, they have an impact on the economic feasibility of the whole project. In this paper, a newly developed process simulation model is presented that allows assessing the duration of the loading and unloading processes, the mass of transported CNG, and the amount of power and energy required by the process. The model is useful to support the design of the system considering different plant components and operating strategies. It is applied to the analysis of the loading and unloading of a ship that meets the GASVESSEL project specifications. The results show that the duration of the process is of the order of magnitude of 100 h, depending on ambient temperature, and that the energy consumption can vary in the range of 150–180 kJ for a unit mass of CNG. Finally, the model is used to simulate the same process with hydrogen, an energy carrier that allows meeting, together with the use of fuel cells, the requirements of zero local emissions. The results show increments of both the final loading temperature and compressor power with respect to the CNG case.

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46

Fuhlbrügge, Steffen, Birgit Quack, Susann Tegtmeier, Elliot Atlas, Helmke Hepach, Qiang Shi, Stefan Raimund y Kirstin Krüger. "The contribution of oceanic halocarbons to marine and free tropospheric air over the tropical West Pacific". Atmospheric Chemistry and Physics 16, n.º 12 (21 de junio de 2016): 7569–85. http://dx.doi.org/10.5194/acp-16-7569-2016.

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Abstract. Emissions of halogenated very-short-lived substances (VSLSs) from the oceans contribute to the atmospheric halogen budget and affect tropospheric and stratospheric ozone. Here, we investigate the contribution of natural oceanic VSLS emissions to the marine atmospheric boundary layer (MABL) and their transport into the free troposphere (FT) over the tropical West Pacific. The study concentrates on bromoform, dibromomethane and methyl iodide measured on ship and aircraft during the SHIVA (Stratospheric Ozone: Halogen Impacts in a Varying Atmosphere) campaign in the South China and Sulu seas in November 2011. Elevated oceanic concentrations for bromoform, dibromomethane and methyl iodide of on average 19.9, 5.0 and 3.8 pmol L−1, in particular close to Singapore and to the coast of Borneo, with high corresponding oceanic emissions of 1486, 405 and 433 pmol m−2 h−1 respectively, characterise this tropical region as a strong source of these compounds. Atmospheric mixing ratios in the MABL were unexpectedly relatively low with 2.08, 1.17 and 0.39 ppt for bromoform, dibromomethane and methyl iodide. We use meteorological and chemical ship and aircraft observations, FLEXPART trajectory calculations and source-loss estimates to identify the oceanic VSLS contribution to the MABL and to the FT. Our results show that the well-ventilated MABL and intense convection led to the low atmospheric mixing ratios in the MABL despite the high oceanic emissions. Up to 45 % of the accumulated bromoform in the FT above the region originates from the local South China Sea area, while dibromomethane is largely advected from distant source regions and the local ocean only contributes 20 %. The accumulated methyl iodide in the FT is higher than can be explained with local contributions. Possible reasons, uncertainties and consequences of our observations and model estimates are discussed.

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47

Hamed, AM, AE Hussin, MM Kamal y AR Elbaz. "Combustion of a hydrogen jet normal to multiple pairs of opposing methane–air mixtures". Proceedings of the Institution of Mechanical Engineers, Part A: Journal of Power and Energy 231, n.º 2 (6 de enero de 2017): 145–58. http://dx.doi.org/10.1177/0957650916685944.

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The combustion performance of a cylindrical burner accommodating up to six multiple pairs of opposing methane–air mixtures with a cross-flow of hydrogen was addressed. The cross-flow initially duplicated the stagnation impact and enriched the vortical structures. Aided by the resulting flow strain, the transport of heat and active species from the hydrogen oxidation zone to the methane reaction zones accelerated the combustion across the opposing premixed flames and reduced the peak temperature across the outer diffusion flame. Increasing the cross-flow/opposing jets’ velocity ratio to 0.89 merged the two stagnation centers and maximized the shearing stress. By the slight increase in the velocity ratio to 1.07, the H and OH pools provided for methane combustion became closer to the ports such that a hydrogen/methane mass percent of 10.3% extended the stoichiometric blowout velocity from 28.3 to 35.7 m/s. Since the turbulent kinetic energy thus increased to 8.4 m2/s2, the firing intensity reached values as high as 48.2 MW/m3. Not only was there a reduction in the residence time for NOx formation, but also the blowout velocity relative gain overrode the relative increase in the NOx formation rates such that the NOx emission index decreased to 17 g/MWhr. By the excessive increase in velocity ratio, the vortical structures shrank such that the NOx exponential increase became dominant above 21 ppm. With fuel-lean mixtures, the hydrogen was partially combusted by the excess air from the opposing flames but the blowout velocity decreased to 13.1 m/s at Φ = 0.50. The hydrogen flame NOx emissions decreased by providing the excess air at larger jets’ diameter/separation ratios, thus reducing the residence times for thermal NOx formation and simultaneously interrupting the prompt NOx formation. At the lean operational limit, tripling the number of opposing jets decreased the hydrogen flame length by 54% such that the NOx emissions decreased by 38.4%.

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48

Churnside, James H. y Percy L. Donaghay. "Thin scattering layers observed by airborne lidar". ICES Journal of Marine Science 66, n.º 4 (25 de febrero de 2009): 778–89. http://dx.doi.org/10.1093/icesjms/fsp029.

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Abstract Churnside, J. H., and Donaghay, P. L. 2009. Thin scattering layers observed by airborne lidar. – ICES Journal of Marine Science, 66: 778–789. More than 2000 km of thin (<3 m) optical scattering layers were identified in 80 000 km of airborne lidar data collected from a variety of oceanic and coastal waters. The spatial characteristics of thin layers varied dramatically from (i) those that were self-contained features consistently <3–4 m thick over their 1–12 km extent to (ii) those that were clearly parts of much longer layers that had gaps and/or regions where the layer became more intense and much thicker than the 3-m criterion. The characteristics of the lidar signal suggest that plankton was the most likely source of scattering. Examples from upwelling regions, areas with large fresh-water influx, and warm-core eddies are presented. The results are quite consistent with the characteristics observed in studies of thin plankton layers in fjords and near-coastal waters. These layers exhibit great spatial variability that is difficult to observe using traditional methods, and examples of layer perturbations by both linear and non-linear internal waves are presented. The results suggest that airborne lidar can be a powerful tool not only for detecting and mapping the spatial extent of thin scattering layers and linking their occurrence to larger scale physical processes, but also for tracking their evolution over time and guiding the ship-based sampling needed to understand their composition, dynamics, and impacts. Such a capability will be crucial in future studies designed to test the hypothesis that thin plankton layers have the spatial extent and intensity to play a key role in controlling the recruitment of fish larvae, biogeochemical cycling, trophic transfer processes, plankton biodiversity, and harmful algal bloom dynamics.

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49

Yang, M., B. J. Huebert, B. W. Blomquist, S. G. Howell, L. M. Shank, C. S. McNaughton, A. D. Clarke et al. "Atmospheric sulfur cycling in the Southeastern Pacific – longitudinal distribution, vertical profile, and diel variability observed during VOCALS-REx". Atmospheric Chemistry and Physics Discussions 11, n.º 1 (24 de enero de 2011): 2873–929. http://dx.doi.org/10.5194/acpd-11-2873-2011.

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Abstract. Dimethylsulfide (DMS) emitted from the ocean is a biogenic precursor gas for sulfur dioxide (SO2) and non-sea-salt sulfate aerosols (SO42). During the VAMOS-Ocean-Cloud-Atmosphere-Land Study Regional Experiment (VOCALS-REx) in 2008, multiple instrumented platforms were deployed in the Southeastern Pacific (SEP) off the coast of Chile and Peru to study the linkage between aerosols and stratocumulus clouds. We present here observations from the NOAA Ship Ronald H. Brown and the NSF/NCAR C-130 aircraft along ~20° S from the coast (70° W) to a remote marine region (85° W). While SO42− and SO2 concentrations were distinctly elevated above background levels in the coastal marine boundary layer (MBL) due to anthropogenic influence (~800 and 80 pptv, respectively), their concentrations rapidly decreased offshore (~100and 25 pptv). Compared to the "mass" entrainment fluxes of SO42− and SO2 from the free troposphere (0.5 ± 0.3 and 0.3 ± 0.2 μmoles m−2 day−1), the sea-to-air DMS flux (3.8 ± 0.1 μmoles m−2 day−1) remained the predominant source of sulfur mass to the MBL. In-cloud oxidation was found to be the most important mechanism for SO2 removal and in situ SO42− production. Surface SO42− loading in the remote region displayed pronounced diel variability, increasing rapidly in the first few hours after sunset and then decaying for the rest of the time. We theorize that the increase in SO42− was due to nighttime recoupling of the MBL that mixed down cloud-processed air, while decoupling and sporadic precipitation scavenging were responsible for the daytime decline in SO42−.

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50

Jessup, A. T. y R. Branch. "Integrated Ocean Skin and Bulk Temperature Measurements Using the Calibrated Infrared In Situ Measurement System (CIRIMS) and Through-Hull Ports". Journal of Atmospheric and Oceanic Technology 25, n.º 4 (1 de abril de 2008): 579–97. http://dx.doi.org/10.1175/2007jtecho479.1.

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Abstract The design and performance of a shipboard-integrated system for underway skin and bulk temperature is presented. The system consists of the Calibrated Infrared In situ Measurement System (CIRIMS) and through-hull temperature sensors. The CIRIMS is an autonomous shipboard radiometer system that measures the sea surface skin temperature Tskin for validation of satellite-derived sea surface temperature products. General design considerations for shipboard radiometer systems are discussed and the philosophy behind the CIRIMS design is presented. Unique features of the design include a constant temperature housing to stabilize instrument drift, a two-point dynamic calibration procedure, separate sky- and sea-viewing radiometers for simultaneous measurements, and the ability to use an infrared transparent window for environmental protection. Laboratory testing and field deployments are used to establish an estimated error budget, which includes instrumentation and environmental uncertainties. The combination of this testing and field comparison to the Marine-Atmosphere Emitted Radiance Interferometer (M-AERI) and Infrared SST Autonomous Radiometer (ISAR) instruments indicates that the CIRIMS meets the design goal of ±0.10°C accuracy. Temperature and pressure sensors were installed in custom-designed through-hull ports on the NOAA research vessel (R/V) Ronald H. Brown and the University of Washington R/V Thomas G. Thompson to complement the CIRIMS measurements. The ports allow sensors to be installed while the ship is in water and can accommodate a variety of sensors. The combined system provides the ability to measure near-surface temperature profiles from the skin to a depth of 5 m while underway.

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