Long-term immersion corrosion of steel subject to large annual variations in seawater temperature and nutrient concentration

2016 ◽  
Vol 13 (8) ◽  
pp. 978-987
Author(s):  
Roman Kovalenko ◽  
Robert E. Melchers ◽  
Boris Chernov
Keyword(s):  
Nutrient Concentration ◽  
Seawater Temperature ◽  
Annual Variations ◽  
Immersion Corrosion ◽  
Corrosion Of Steel

Corrosion of steels and irons immersed in natural seawater for up to 600 years

CORROSION ◽  
10.5006/3967 ◽  
2021 ◽  
Author(s):  
Robert Melchers
Keyword(s):  
Power Law ◽  
Seawater Temperature ◽  
Bridge Piers ◽  
Natural Seawater ◽  
Outward Diffusion ◽  
Wrought Iron ◽  
Corrosion Loss ◽  
Immersion Corrosion ◽  
Anaerobic Corrosion

Marine immersion corrosion observations for archaeological and other data, including from shipwrecks, wrought iron anchors and cast iron bridge piers are used to estimate corrosion losses in natural unpolluted coastal and near-coastal seawaters for exposures up to about 600 years. Empirical functions for the development of corrosion loss with time were then developed, standardized to 20˚C mean seawater temperature. The resulting slightly non-linear corrosion loss trend, represented by a modified form of the power law, is consistent with Phase 4 of the previously proposed bi-modal corrosion model. These observations support the notion that the rate of long-term corrosion is controlled by outward diffusion, through the rust layers, of gaseous hydrogen generated by the cathodic hydrogen evolution reaction under predominantly anaerobic corrosion conditions. The power-law trend also provides good extrapolation from shorter- term data. For practical purposes for exposures < 100 years in seawaters with mean temperature around 20˚C, a linear model, with longer-term corrosion rate 0.06 mm/y at 20˚C, is sufficiently accurate.

Long-term changes in some benthic species in the Firth of Clyde, with particular reference to Tellina tenuis da Costa

1986 ◽  
Vol 90 ◽  
pp. 287-302 ◽  
Author(s):  
P. R. O. Barnett ◽  
J. Watson
Keyword(s):  
Seawater Temperature ◽  
Present Knowledge ◽  
Seasonal Cycles ◽  
Benthic Species ◽  
Temperature Changes ◽  
Annual Variations ◽  
Long Term Changes ◽  
Natural Temperature ◽  
A Site

SynopisPresent knowledge of long-term changes in benthic species in the Firth of Clyde is reviewed.Recent work on the annual variations in seasonal cycles of the sand-dwelling bivalve Tellina tenuis da Costa shows some correlations with natural and man-made variations in seawater temperature. Between 1973 and 1984 inclusive good settlements of young occurred on the two beaches examined in the autumns of years when higher mean seawater temperatures occurred in June and July. The implications are discussed in relation to cycles of climatic change. In general, settlements at Hunterston, a thermally enriched area, were considerably greater than at Kames Bay, a site affected only by natural temperature changes. However, T. tenuis at Kames Bay grew to much larger maximum sizes than at Hunterston, except in 1979, when Hunterston animals were larger. The possible interactions of food availability and the modifying effects of heated discharges are discussed.Earlier results by Dr A. C. Stephen between 1926 and 1951 are reassessed in the light of present knowledge.

scholarly journals Interannual variability of larval fish assemblages associated with water masses in winter in the Taiwan Strait during 2007–2013

2021 ◽  
Author(s):  
Yu-Kai Chen ◽  
Chia-Yi Pan ◽  
Yi-Chen Wang ◽  
Hsiu-Ju Tseng ◽  
Bo-Kun Su ◽  
...  
Keyword(s):  
Fish Assemblages ◽  
Larval Fish ◽  
Taiwan Strait ◽  
Assemblage Structure ◽  
Sea Surface ◽  
Coastal Current ◽  
Annual Variations ◽  
Frontal Zones ◽  
The Taiwan Strait

AbstractIn this study, the interannual variations of ichthyoplankton assemblages in the Taiwan Strait (TS) during the winters of 2007–2013 were determined. The cold China Coastal Current (CCC) and Mixed China Coastal Water (MCCW) intruded into the TS and impinged with the warm Kuroshio Branch Current (KBC) with annual variations. Consequently, the ichthyoplankton community in the TS was mainly structured into two assemblages characterized by differing environmental conditions. The composition of the warm KBC assemblage was relatively stable and was characterized by Diaphus B and Bregmaceros spp. By contrast, the cold MCCW assemblage demonstrated considerable variations over the years, with demersal Gobiidae and Scorpaenidae families considered the most representative. In addition, Benthosema pterotum and Trichiurus spp. were common in both KBC and MCCW assemblages. The distribution of the KBC assemblage demonstrated sharp boundaries in the frontal zones, whereas changes in the assemblage structure between the frontal zones were gradual for the MCCW assemblage, particularly when demersal taxa were dominant. Sea surface temperature and salinity were most strongly associated with variability in the assemblage structure during the study period. Thus, this paper provides a better understanding of long-term larval fish dynamics during winter in the TS.

scholarly journals INCREASE OF THE THERMOCLINE LAYER DUE TO TSUNAMI 2004 IN NANGRO ACEH DARUSSALAM WATERS

2011 ◽  
Vol 3 (1) ◽  
Author(s):  
Hadikusumah Hadikusumah ◽  
J. D. Lekalete
Keyword(s):  
Indian Ocean ◽  
Light Transmission ◽  
Mixed Layer Depth ◽  
Heat Content ◽  
Annual Variations ◽  
The Indian Ocean ◽  
Local Water ◽  
Straits Of Malacca ◽  
Tsunami Energy

Research of physical oceanographic conditions post-tsunami was carried out and subsequently compared with the pre-tsunami 1998. Measurement of suhu, salinity and light transmission was conducted by CTDSBE911pls Model. Results showed that the flow in the Straits of Malacca flowed into the northwest and turned back into the Strait of Bengal and the next rotation into the flow of waters along the west coast of Nangro Aceh Darusalam (NAD). The mainstream off coast NAD in the Indian Ocean flowed to the northwest. Upper thermocline layer (17 m to 50 m) moved upward in 2005 and 2006 compared with previous data 1998 (90 m to 125 m). The moving upward thermocline in 2006 was allegedly due to the influence of Indian Ocean Dipole (IOD) positive. This requires further verification through long-term data collection to determine the monthly and annual variations, which will be compared with previous research. Light transmission (Tx) in 2005 from the surface to near the bottom (water column) was found lower than the year 1998 and 2006. This result was allegedly caused by resuspension from the seabed by energy turbulent produced by the tsunami. Heat content between 5 to 65 m depth in 2005 was higher than in 1998 and 2006. The higher heat content during the year of 2005 (post tsunami) was caused by friction due to the influence of tsunami energy, which predominantly found in the mixed layer depth. Type of water masses in the study area was a mixing between the local water mass, Malacca Strait Water (MSA), Bay of Bengal Water (BBW) under the influence of Arab Waters (AW), and the Indian Deep Water (IDW).Keywords: current, thermocline, heat content, watermass type, and Nangro Aceh Darusalam

scholarly journals A Forty-Year Karstic Critical Zone Survey (Baget Catchment, Pyrenees-France): Lithologic and Hydroclimatic Controls on Seasonal and Inter-Annual Variations of Stream Water Chemical Composition, pCO2, and Carbonate Equilibrium

Water ◽  
2020 ◽  
Vol 12 (5) ◽  
pp. 1227
Author(s):  
Francesco Ulloa-Cedamanos ◽  
Jean-Luc Probst ◽  
Stephane Binet ◽  
Thierry Camboulive ◽  
Virginie Payre-Suc ◽  
...  
Keyword(s):  
Chemical Composition ◽  
Stream Water ◽  
Saturation Index ◽  
Hydrological Regime ◽  
Mineral Dissolution ◽  
Annual Variations ◽  
Water Chemical Composition ◽  
Calcite Saturation ◽  
Karst Catchment

The long-term trends and seasonal patterns of stream water chemical composition in a small remote forested karst catchment, were investigated from 1978 to 2018. Calcium, magnesium, and bicarbonates, the dominant ions, increased over the period together with temperature, while sulfates decreased. Carbonate and sulfate mineral dissolution was the main source of these elements. These trends and the seasonal opposite patterns of discharge vs. temperature, calcite saturation index vs. pCO2 and bicarbonate vs. sulfates, suggested the influence of discharge, of reduced long-range atmospheric pollution, and of increasing air temperature on biological activity and carbonate dissolution. Furthermore, the hydrological regime controlled the seasonal stream water chemical composition and fluxes by: (i) a dilution during the high discharge period, (ii) a change in the contribution rate of the waters draining different lithological areas in the catchment, e.g., the increased sulfates to bicarbonates ratio during summer low flows, with a maximum alkalinity decrease of 24%, and (iii) a “piston” and a “flushing” effects of dissolved elements stored in soils and epikarst with the first autumn heavy rains. Long-term stream water hydrochemical surveys of karst system have proved to be powerful indicators of biogeochemical processes, water sources and pathways under variable natural and anthropogenic environmental pressure conditions.

Evaluation on Environmental Corrosion Damage of Steel Domes

2010 ◽  
Vol 44-47 ◽  
pp. 163-167
Author(s):  
Bo Chen ◽  
Jian Feng Wei ◽  
Jin Zheng
Keyword(s):  
Natural Frequency ◽  
Corrosion Damage ◽  
Exponential Model ◽  
Nonlinear Static Analysis ◽  
Space Structures ◽  
Structural Members ◽  
Nonlinear Static ◽  
Corrosion Of Steel

The evaluation on environmental corrosion damage of steel domes is carried out in this study through an integration of knowledge in material science and structural analysis. The refined exponential model for estimating corrosion of steel materials is presented based on long-term experimental data available. The formula for relating structural natural frequency sensitivity to structural member thickness is then derived to assess the sensitivity of natural frequency to variation of member thickness due to corrosion. The nonlinear static analysis is conducted to evaluate effects of atmospheric corrosion on the stress of structural members and the safety of steel space structures. A real steel dome built in China is taken as the case study to examine the feasibility of the proposed approach and to assess the potential corrosion damage to the structure..

Primary Production in a Tidally Energetic Fjord: Evidence of Seasonal and Inter-annual Tidal Forcing

1989 ◽  
Vol 46 (12) ◽  
pp. 2166-2172 ◽  
Author(s):  
T. A. Kessler ◽  
T. R. Parsons
Keyword(s):  
Primary Production ◽  
Standing Stock ◽  
Covariance Structure ◽  
Static Stability ◽  
Data Set ◽  
Annual Variations ◽  
Basin Surface ◽  
Statistical Relationships ◽  
Inflow Jet

A long term data set collected from a tidally energetic sill fjord was analyzed for its statistical relationships between primary production indices and several represented environmental variables. The analysis identified variance and covariance structure in these variables implicating changes in water column clarity, in inter-annual variability of phytoplankton carbon uptake rate, and the static stability of basin surface water in phytoplankton standing stock. The biomass–stability relationship was found to be seasonally dependent, with biomass positively correlated with stability in the summer and negatively correlated in the spring/fall, and restricted to waters under the direct mixing influence of the tidal inflow jet. These statistical patterns are discussed in terms of a possible control of primary production by seasonal and inter-annual variations in tidal inflow buoyancy.

scholarly journals Influence of Corn (Zea maysL.) Cultivar Development on Grain Nutrient Concentration

2012 ◽  
Vol 2012 ◽  
pp. 1-7 ◽  
Author(s):  
Carla Fernanda Ferreira ◽  
Antônio Carlos Vargas Motta ◽  
Stephen A. Prior ◽  
Carlos Bruno Reissman ◽  
Nicolas Z. dos Santos ◽  
...  
Keyword(s):  
Nutrient Concentration ◽  
High Yield ◽  
High Fertility ◽  
Breeding Programs ◽  
Nutrient Quality ◽  
Cultivar Development ◽  
Zn And Cu In ◽  
Corn Productivity ◽  
Climate Events

While corn productivity has been increased by the adoption of high-yield hybrids, there are concerns that increased grain potential may be associated with diminished grain nutrient concentration. Ten corn (Zea maysL.) cultivars representing five technological levels (landrace variety, commercial variety, and double, triple, and single cross-hybrids) were cropped on a Rhodic Ferralsol Eutric soil with high fertility in 2006 (dry year) and 2007 (normal year) in Rolândia County, Brazil. At maturity, grain was evaluated for concentrations of P, K, Ca, Mg, Fe, Mn, Zn, and Cu. In general, differences among cultivars were noted for all nutrients in both years. Concentrations of P, K, Fe, and Mn were lower in the dry year, while Ca, Mg, Cu, and Zn were higher. Soil water availability appeared to exert more influence on grain nutrient concentration than did cultivar development; nutrient removal due to grain harvest was also greatly influenced by rainfall patterns and their impact on corn productivity. Even though genetic differences were noted, which may be useful to breeding programs, long-term testing in subtropical environments will be required to clarify the interaction between genetics and climate events on grain nutrient quality and exportation.

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