Bacterial Production in Anaerobic Water Columns

The hydrodynamic performance of oscillating water column (OWC) depends on the depth of the water, the size of the water column and its arrangement, which affects the oscillation of the water surface in the column. An experimental method was conducted by testing 4 water depths with wave periods of 1-3 s. All data recorded by the sensor is then processed and presented in graphical form. The research focused on analyzing the difference in wave power absorption capabilities of the three geometric types of OWC based on arrangements of water columns. The OWC devices designed as single water column, the double water column in a series arrangement which was perpendicular to the direction of wave propagation, and double water column in which the arrangement of columns was parallel to the direction of wave propagation. This paper discussed several factors affecting the amount of power absorbed by the device. The factors are the ratio of water depth in its relation to wavelength (kh) and the inlet openings ratio (c/h) of the devices. The test results show that if the water depth increases in the range of kh 0.7 to 0.9, then the performance of the double chamber oscillating water column (DCOWC) device is better than the single chamber oscillating water column (SCOWC) device with maximum efficiency for the parallel arrangement 22,4%, series arrangement 20.8% and single column 20.7%. However, when referring to c/h, the maximum energy absorption efficiency for a single column is 27.7%, double column series arrangement is 23.2%, and double column parallel arrangement is 29.5%. Based on the results of the analysis, DCOWC devices in parallel arrangement showed the ability to absorb better wave power in a broader range of wave frequencies. The best wave of power absorption in the three testing models occurred in the wave period T = 1.3 seconds.

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EVALUATION OF CERAMIC AND MEMBRANE DIFFUSERS UNDER DIFFERENT WATER COLUMNS WITH PULSATING AIRFLOW METHOD

International Journal of Energy for a Clean Environment ◽

10.1615/interjenercleanenv.2020033627 ◽

2020 ◽

Vol 21 (2) ◽

pp. 145-167 ◽

Cited By ~ 1

Author(s):

Ahmed Ali Alkhafaji ◽

Ryoichi Samuel Amano

Keyword(s):

Water Columns

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0108 - Microbial Diversity in Mid Indian Ocean; from Water Columns to Sediments of Hydrothermal Vent area

10.26226/morressier.5b5199bdb1b87b000ecee22b ◽

2018 ◽

Author(s):

Kaekyoung Kwon ◽

Mi Jeong Park

Keyword(s):

Indian Ocean ◽

Microbial Diversity ◽

Hydrothermal Vent ◽

Water Columns

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Inflammation in children with cystic fibrosis: contribution of bacterial production of long-chain fatty acids

Pediatric Research ◽

10.1038/s41390-021-01419-4 ◽

2021 ◽

Author(s):

Erin Felton ◽

Aszia Burrell ◽

Hollis Chaney ◽

Iman Sami ◽

Anastassios C. Koumbourlis ◽

...

Keyword(s):

Cystic Fibrosis ◽

Fatty Acid ◽

Antibiotic Treatment ◽

Bacterial Production ◽

Clinical Status ◽

Achromobacter Xylosoxidans ◽

List Type ◽

Future Studies ◽

Long Chain

Abstract Background Cystic fibrosis (CF) affects >70,000 people worldwide, yet the microbiologic trigger for pulmonary exacerbations (PExs) remains unknown. The objective of this study was to identify changes in bacterial metabolic pathways associated with clinical status. Methods Respiratory samples were collected at hospital admission for PEx, end of intravenous (IV) antibiotic treatment, and follow-up from 27 hospitalized children with CF. Bacterial DNA was extracted and shotgun DNA sequencing was performed. MetaPhlAn2 and HUMAnN2 were used to evaluate bacterial taxonomic and pathway relative abundance, while DESeq2 was used to evaluate differential abundance based on clinical status. Results The mean age of study participants was 10 years; 85% received combination IV antibiotic therapy (beta-lactam plus a second agent). Long-chain fatty acid (LCFA) biosynthesis pathways were upregulated in follow-up samples compared to end of treatment: gondoate (p = 0.012), oleate (p = 0.048), palmitoleate (p = 0.043), and pathways of fatty acid elongation (p = 0.012). Achromobacter xylosoxidans and Escherichia sp. were also more prevalent in follow-up compared to PEx (p < 0.001). Conclusions LCFAs may be associated with persistent infection of opportunistic pathogens. Future studies should more closely investigate the role of LCFA production by lung bacteria in the transition from baseline wellness to PEx in persons with CF. Impact Increased levels of LCFAs are found after IV antibiotic treatment in persons with CF. LCFAs have previously been associated with increased lung inflammation in asthma. This is the first report of LCFAs in the airway of persons with CF. This research provides support that bacterial production of LCFAs may be a contributor to inflammation in persons with CF. Future studies should evaluate LCFAs as predictors of future PExs.

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Performance Analysis on the Use of Oscillating Water Column in Barge-Based Floating Offshore Wind Turbines

Mathematics ◽

10.3390/math9050475 ◽

2021 ◽

Vol 9 (5) ◽

pp. 475

Author(s):

Payam Aboutalebi ◽

Fares M’zoughi ◽

Izaskun Garrido ◽

Aitor J. Garrido

Keyword(s):

Wind Turbines ◽

Positive Impact ◽

Offshore Wind ◽

Offshore Wind Turbines ◽

Floating Offshore Wind Turbines ◽

Water Columns ◽

Numerical Tools ◽

Oscillating Water Columns ◽

The Given ◽

The Waves

Undesired motions in Floating Offshore Wind Turbines (FOWT) lead to reduction of system efficiency, the system’s lifespan, wind and wave energy mitigation and increment of stress on the system and maintenance costs. In this article, a new barge platform structure for a FOWT has been proposed with the objective of reducing these undesired platform motions. The newly proposed barge structure aims to reduce the tower displacements and platform’s oscillations, particularly in rotational movements. This is achieved by installing Oscillating Water Columns (OWC) within the barge to oppose the oscillatory motion of the waves. Response Amplitude Operator (RAO) is used to predict the motions of the system exposed to different wave frequencies. From the RAOs analysis, the system’s performance has been evaluated for representative regular wave periods. Simulations using numerical tools show the positive impact of the added OWCs on the system’s stability. The results prove that the proposed platform presents better performance by decreasing the oscillations for the given range of wave frequencies, compared to the traditional barge platform.

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Switching Control Strategy for Oscillating Water Columns Based on Response Amplitude Operators for Floating Offshore Wind Turbines Stabilization

Applied Sciences ◽

10.3390/app11115249 ◽

2021 ◽

Vol 11 (11) ◽

pp. 5249

Author(s):

Payam Aboutalebi ◽

Fares M’zoughi ◽

Itziar Martija ◽

Izaskun Garrido ◽

Aitor J. Garrido

Keyword(s):

Switching Control ◽

Response Amplitude ◽

Offshore Wind ◽

Oscillating Water Column ◽

Offshore Wind Turbines ◽

Floating Offshore Wind Turbines ◽

Water Columns ◽

Switching Control Strategy ◽

Response Amplitude Operators ◽

Oscillating Water Columns

In this article, a new strategy for switching control has been proposed with the aim of reducing oscillations in floating offshore wind turbines. Such oscillations lead to a shortage in the system’s efficiency, lifespan and harvesting capability of wind and wave energies. In order to study the decreasing of undesired oscillations in the system, particularly in pitch and top tower fore-aft movements, a square-shaped platform barge equipped with four symmetric oscillating water columns has been considered. The oscillating water columns’ air flux valves allow to operate the air columns so that to control the barge movements caused by oscillatory motion of the waves. In order to design the control scheme, response amplitude operators have been used to evaluate the performance of the system for a range of wave frequency profiles. These response amplitude operators analysis makes it possible to implement a switching control strategy to adequately regulate the valves opening/closing transition. The obtained results show that the proposed controlled oscillating water column-based barge present a better performance compared to the traditional barge one. In the case study with the period of 10 s, the results indicate the significant oscillation reduction for the controlled oscillating water column-based system compared to the standard barge system by 30.8% in pitch angle and 25% in fore-aft displacement.

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Seasonal Variability in Middepth Gyral Circulation Patterns in the Central East/Japan Sea as Revealed by Long-Term Argo Data

Journal of Physical Oceanography ◽

10.1175/jpo-d-15-0157.1 ◽

2016 ◽

Vol 46 (3) ◽

pp. 937-946 ◽

Cited By ~ 1

Author(s):

Sok Kuh Kang ◽

Young Ho Seung ◽

Jong Jin Park ◽

Jae-Hun Park ◽

Jae Hak Lee ◽

...

Keyword(s):

Seasonal Variation ◽

Seasonal Variability ◽

Japan Sea ◽

Circulation Pattern ◽

Japan Basin ◽

Wind Stress Curl ◽

Argo Data ◽

Circulating Water ◽

Significant Seasonal Variation ◽

Water Columns

AbstractTrajectories of Argo floats deployed in the East/Japan Sea from 2001 to 2014 reveal that the middepth gyral circulation pattern of the Japan basin, the central part of the East/Japan Sea, undergoes a seasonal variation. The middepth circulation of the Japan basin is found to be characterized usually by the gyres trapped to the east of the Bogorov Rise (E-gyres) and those extending farther westward into the whole basin (BW-gyres). The E-gyre trajectories are generally associated with the turning of the floats toward deeper regions off the isobaths. This occurs in winter either on the northern or eastern side of the eastern Japan basin. It seems that the upstream part of the otherwise BW-gyre is subject to a strong negative wind stress curl in winter, and there the circulating water columns are driven toward the deeper region, thus triggering the formation of the E-gyre. The topographic effect associated with the Bogorov Rise seems to interfere thereafter in the process of determining the passage of the E-gyre. Otherwise, the water columns continue to flow along the isobaths, hence maintaining the BW-gyre. To the knowledge of the authors, this is the first observational evidence of seasonal variability in the middepth gyral circulation pattern in the East/Japan Sea. It suggests that oceanic middepth circulation, usually known to be quasi steady or slowly varying on climatological time scales, might also undergo a significant seasonal variation as it does in the East/Japan Sea.

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