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Živković, Igor, Jan Gačnik, Slaven Jozić, Jože Kotnik, Mladen Šolić i Milena Horvat. "A Simplified Approach to Modeling the Dispersion of Mercury from Precipitation to Surface Waters—The Bay of Kaštela Case Study". Journal of Marine Science and Engineering 10, nr 4 (14.04.2022): 539. http://dx.doi.org/10.3390/jmse10040539.
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Wet deposition is the main source of mercury (Hg) from the atmosphere to the Earth’s surface. However, the processes that govern the dispersion of deposited Hg in seawater are currently not well understood. To address this issue, total mercury (THg) concentrations in surface seawaters and precipitation were determined on a monthly basis in the Bay of Kaštela (Central Adriatic Sea). Following the assumption that deposited THg is diluted in the seawater bulk due to mixing processes, an exponential decay-like model was developed and the wet deposition of THg was normalized based on periods between precipitation events and seawater sampling. Normalized wet deposition of THg showed significant correlation with the THg gradient in surface seawater after removal of an outlier. To explain the observed outlier, further data normalization included wind data to account for enhanced seawater mixing due to strong winds. Wind-normalized THg deposition of all datapoints showed significant correlation with the THg gradient in surface seawater. The correlation showed that the THg gradient in surface seawater of 0.378 pg L−1 m−1 corresponds to THg wet deposition of 1 ng m−2 after including the influence of wind speed on seawater mixing.
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Hastuti, Yuni Puji, Yuli Siti Fatma, Hardi Pitoyo, Yusli Wardiatno i Siska Tridesianti. "Bacterial and plankton communities in mariculture water sources: a case study in Nampu and Sembukan seawaters, Wonogiri, Indonesia". Natura Croatica 30, nr 2 (31.12.2021): 351–66. http://dx.doi.org/10.20302/nc.2021.30.22.
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Seawaters in Indonesia, part of the tropical marine ecosystem, have great microbial and plankton diversity. Seawater is used as a water source for marine aquacultures, such as shrimp, milkfish, lobster, and mud crab. Sustainability of environmental resources for supporting aquaculture activities can be assessed by analyzing the actual conditions of the water source environment, including bacterial and plankton communities. However, the characteristics of bacteria and plankton communities in Indonesian seawaters have not been well documented. In this study, we investigated the bacterial and plankton communities in surface seawater from two coastal areas, i.e. Nampu and Sembukan, Wonogiri regency, Central Java, Indonesia. Bacterial diversity was analyzed using the Illumina-based high throughput sequencing with a primer set targeting the V3-V4 region of the bacterial 16S rRNA gene. Meanwhile, the plankton community (phytoplankton and zooplankton) was calculated and identified using a counting chamber method. Sequencing analysis revealed that the five dominant bacterial phyla in the two seawater samples were similar, consisting of Proteobacteria, Firmicutes, Actinobacteria, Bacteriodetes, and Cyanobacteria. Although the two sites are separated by several kilometres, the distribution of dominant bacterial phyla in both seawater samples is similar. Phytoplankton in Nampu and Sembukan were similarly dominated by Trichodesmium sp., Navicula sp., and Rhabdonema sp. Dominant zooplankton in the two sites were Euterpina, Nauplius, Oithona sp., Oncaea sp., Tigriopus sp., and Gastropoda larvae. The seawater in Nampu and Sembukan is suitable as a water source for aquaculture.
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Ding, Fei, Takao Yamashita i Han Soo Lee. "Atmosphere-Ocean-Groundwater Modeling System for Seawater Intrusion Simulation in Liaodong Bay Coastal Plain, China". Advanced Materials Research 518-523 (maj 2012): 4155–60. http://dx.doi.org/10.4028/www.scientific.net/amr.518-523.4155.
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Precipitation and seawater level are the two important factors to be considered in seawater intrusion simulation. However, these data are lacking in some regions of the world. Thus, limits the study on seawater intrusion. Considering the lack of availability of data on precipitation and seawater level, an atmosphere–ocean-groundwater modeling system was constructed in this paper. In the modeling system, the atmosphere model (MM5) and the ocean model (POM) is used to simulate the precipitation and seawater level, respectively while the SEAWAT model is used for groundwater model simulation. The system is used for seawater intrusion simulation case study in the Liaodong Bay coastal plain. The study shows that the atmosphere–ocean-groundwater modeling system provides a very reasonable result.
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Nasser, Abid M., Lital Telser i Yeshayahu Nitzan. "Effect of sunlight on the infectivity ofCryptosporidium parvumin seawater". Canadian Journal of Microbiology 53, nr 9 (wrzesień 2007): 1101–5. http://dx.doi.org/10.1139/w07-043.
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The prevalence of pathogenic microorganisms in seawater can result in waterborne and food borne outbreaks. This study was performed to determine the effect of sunlight and salinity on the die-off of Cryptosporidium parvum . Cryptosporidium parvum oocysts, Escherichia coli , and MS2 coliphage were seeded into tap water and seawater samples and then exposed to sunlight. The die-off of C. parvum in seawater, as measured by infectivity, was greater under sunlight (–3.08 log10) than under dark conditions (–1.31 log10). While, no significant difference was recorded in the die-off of C. parvum, under dark conditions, in tap water as compared to seawater (P < 0.05), indicating that the synergistic effect of salinity and sunlight was responsible for the enhanced die-off in seawater. The die-off of MS2 coliphage and E. coli was greater than that observed for C. parvum under all tested conditions. This indicates that these microorganisms cannot serve as indicators for the presence of C. parvum oocysts in seawaters. The results of the study suggest that C. parvum can persist as infectious oocysts for a long time in seawater and can thus pose a serious hazard by direct and indirect contact with humans.
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Abd-Elhamid, Hany F., Gamal M. Abdel-Aal, Maha Fahmy, Mohsen Sherif, Martina Zeleňáková i Ismail Abd-Elaty. "Experimental and Numerical Study to Investigate the Impact of Changing the Boundary Water Levels on Saltwater Intrusion in Coastal Aquifers". Water 14, nr 4 (18.02.2022): 631. http://dx.doi.org/10.3390/w14040631.
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Experimental and numerical models can be used to investigate saltwater intrusion (SWI) in coastal aquifers. Sea level rise (SLR) and decline of freshwater heads due to climate change are the two key variables that may affect saltwater intrusion. This study aims to give a better understanding of the impact of increasing seawater levels and decreasing freshwater heads due to climate change and increasing abstraction rates due to overpopulation using experimental and numerical models on SWI. The experimental model was conducted using a flow tank and the SEAWAT code was used for the numerical simulation. Different scenarios were examined to assess the effect of seawater rise and landside groundwater level decline. The experimental and numerical studies were conducted on three scenarios: increasing seawater head by 25%, 50% and 75% from the difference between seawater and freshwater heads, decreasing freshwater head by 75%, 50% and 25% from the difference between seawater and freshwater heads, and a combination of these two scenarios. Good agreement was attained between experimental and numerical results. The results showed that increasing the seawater level and decreasing freshwater head increased saltwater intrusion, but the combination of these two scenarios had a severe effect on saltwater intrusion. The numerical model was then applied to a real case study, the Biscayne aquifer, Florida, USA. The results indicated that the Biscayne aquifer is highly vulnerable to SWI under the possible consequences of climate change. A 25 cm seawater rise and 28% reduction in the freshwater flux would cause a loss of 0.833 million m3 of freshwater storage per each kilometer width of the Biscayne aquifer. This study provides a better understanding and a quantitative assessment for the impacts of changing water levels’ boundaries on intrusion of seawater in coastal aquifers.
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Βουδούρης, K., K. Νίκας i A. Αντωνάκος. "STUDY OF EVOLUTION OF THE SEAWATER INTRUSION IN COASTAL AQUIFERS. CASE STUDY: THE COASTAL AQUIFER SYSTEM OF NW ACHAIA". Bulletin of the Geological Society of Greece 36, nr 4 (1.01.2004): 1952. http://dx.doi.org/10.12681/bgsg.16690.
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Seawater intrusion problems are recorded in coastal aquifers, which constitute the main sources of drinking water and agricultural irrigation in many countries. The aim of this work is to describe the evolution of the salinity distribution by seawater intrusion, based on results from chemical analyses, of 29 groundwater samples in the NWAchaia area (Peloponnesus, Greece). The study of these data indicates that aquifer waters in large part of area reflect salinization related to seawater intrusion. The occurrence of Ca-CI hydrochemical types of groundwater indicates active seawater intrusion. Cation exchange is the most noticeable hydrogeochemical process in the movement of the saline front in the coastal aquifer. Geographical distribution of Careact index was mapped. The areas with advance or decline of the seawater intrusion front are defined from this map.
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Seiedi, Omolbanin, Mohammad Zahedzadeh, Emad Roayaei, Morteza Aminnaji i Hossein Fazeli. "Experimental and modeling study of wettability alteration through seawater injection in limestone: a case study". Petroleum Science 17, nr 3 (9.01.2020): 749–58. http://dx.doi.org/10.1007/s12182-019-00407-y.
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AbstractWater flooding is widely applied for pressure maintenance or increasing the oil recovery of reservoirs. The heterogeneity and wettability of formation rocks strongly affect the oil recovery efficiency in carbonate reservoirs. During seawater injection in carbonate formations, the interactions between potential seawater ions and the carbonate rock at a high temperature can alter the wettability to a more water-wet condition. This paper studies the wettability of one of the Iranian carbonate reservoirs which has been under Persian Gulf seawater injection for more than 10 years. The wettability of the rock is determined by indirect contact angle measurement using Rise in Core technique. Further, the characterization of the rock surface is evaluated by molecular kinetic theory (MKT) modeling. The data obtained from experiments show that rocks are undergoing neutral wetting after the aging process. While the wettability of low permeable samples changes to be slightly water-wet, the wettability of the samples with higher permeability remains unchanged after soaking in seawater. Experimental data and MKT analysis indicate that wettability alteration of these carbonate rocks through prolonged seawater injection might be insignificant.
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Wang, Hongbo, Zhipeng Li, Xiaoguo Wang, Qingsong Zhang i Lianzhen Zhang. "Study on Grouted Body Deterioration Mechanism of Sand Layer in Seawater Environment". Advances in Materials Science and Engineering 2021 (9.09.2021): 1–8. http://dx.doi.org/10.1155/2021/6329257.
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Water-rich sand is a common stratum in marine underground engineering. Grouting is the most common method for solving geological disasters in water-rich sand. However, the marine environment differs greatly from the land environment. The erosion and seepage of seawater ion cause significant deterioration of grouted body, which reduces the physical and mechanical properties of grouted body. The maintenance of grouted body performance is the guarantee of long-term safe operation of the tunnel in the marine environment. In order to solve the problem of long-life grouting design for sand layer in seawater environment, an accelerated test of grouted body erosion under seawater erosion environment is designed to study the mesomorphological characteristics of seawater erosion on grouted body erosion and to reveal the mechanism of seawater erosion and solids. The evolution law of grouting plus solid strength under different slurry water-cement ratios and different seawater erosion time conditions is analyzed. The results show that the grouting plus solid effective time for water-cement ratios of 0.8 : 1, 1 : 1, 1.4 : 1, and 2 : 1 is 75a, 60a, 30a, and 15a; the index of strength degradation ratio of seawater environment to grouting plus solids is proposed, and the quantitative relationship between seawater erosion time and grouting plus solids strength is established, which provides theoretical basis for sand layer grouting reinforcement in seawater environment. We hope to provide some reference for the design and construction of sand grouting in seawater environment.
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Ding, Rui, Ziyu Wang, Xiangyu Zhao, Peng Cao, Xin Chen i Wenjing Chen. "Experimental Study on Coastal Sediment Reinforcement by Induced Carbonate Precipitation by Different Enzyme Sources". Water 15, nr 8 (13.04.2023): 1525. http://dx.doi.org/10.3390/w15081525.
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Coastal erosion is increasing worldwide due to the increasing frequency of extreme natural phenomena and excessive human exploitation. In this study, a small model experiment was conducted to investigate the solidification effects of three enzyme sources—soybean urease, freshwater Bacillus pasteurella, and seawater domesticated Bacillus pasteurella—on coastal sediments and their impacts in a seawater environment. The solidifying effect of different enzyme sources was determined by measuring the mechanical properties and corrosion resistance of the cured specimen model. The influence of solidified seawater in a seawater environment was obtained by measuring the changes in the pH value, calcium ion concentration, and ammonia nitrogen content of solidified seawater. The results show that different enzyme sources have a certain strengthening effect on coastal sediments. The mechanical properties of coastal sediments can be enhanced by increasing the amount of enzyme solution or level of solidification and can effectively resist simulated flow erosion. Comparing the reinforcement effects of different enzyme sources, it can be seen. It was observed that Bacillus pasteurella acclimated in seawater had better reinforcement effects than Bacillus pasteurella fresh water, and Bacillus pasteurella fresh water had better reinforcement effects than soybean urease. In the seawater measurement tests, the solidification of coastal sediments using different enzyme sources led to a decrease in the seawater pH value, and the acidification of seawater dissolved the generated calcium carbonate, increased the concentration of calcium ions in seawater, and produced ammonia nitrogen as a byproduct in the seawater. It was observed that, compared with the other two enzyme source solutions, the seawater-domesticated Bacillus pasteurella can better adapt to the high-salt environment of seawater, microbial metabolism is not inhibited, urea decomposition ability is improved, and calcium carbonate production is higher, which can effectively improve the engineering characteristics of coastal sediments and play a positive role in coastal protection and development.
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Angel, Brad M., Simon C. Apte, Graeme E. Batley i Mark D. Raven. "Lead solubility in seawater: an experimental study". Environmental Chemistry 13, nr 3 (2016): 489. http://dx.doi.org/10.1071/en15150.
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Environmental contextMany trace metals including lead are only sparingly soluble in seawater and may exist in both dissolved and particulate forms (e.g. as precipitates). Aquatic organisms may experience different toxic effects from exposure to dissolved and particulate trace metals. This study reports the limits to lead solubility in seawater that influence the exposure to these forms of lead in the field and the laboratory. AbstractA combination of laboratory investigations and thermodynamic modelling were conducted in order to gain an understanding of the factors controlling lead solubility in seawater. In experiments where increasing amounts of lead were added to seawater (in order to avoid supersaturation) and equilibrated for up to 28 days, the maximum solubility was ~2mgL–1 (pH 8.15, 22°C). However, at higher added lead concentrations, which caused the rapid formation of lead precipitates, the solution chemistry became dynamic and the observed solubility was markedly lower, varying with both reaction time and precipitate concentration. For instance, when seawater solutions were spiked with 10mgL–1 of total lead, precipitation occurred immediately and only 1.6mgL–1 of dissolved lead was measured after 1h, with this concentration decreasing to 1.3mgL–1 after 28 days. The solubility of lead in artificial seawater (0.68mgL–1) was much lower than in natural seawater. This difference was attributed to the significant role played by natural organic matter in complexing dissolved lead. X-Ray diffraction and elemental analysis data suggest that the phase controlling lead solubility is a previously unidentified lead chlorocarbonate, which rapidly transforms to hydrocerussite on washing with deionised water. These observations are of particular relevance to toxicity tests where organisms are exposed to wide ranges of metal concentrations in order to obtain dose–response curves.
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Li, Ying Tao, Ling Zhou, Mao Jiang, Yu Zhang i Jun Shao. "Experimental Study on Mechanical Property of Concrete Based on Seawater and Sea Sand". Advanced Materials Research 641-642 (styczeń 2013): 574–77. http://dx.doi.org/10.4028/www.scientific.net/amr.641-642.574.
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In this paper, the mechanical property experiments of concrete based on the seawater and sea sand have been carried in different raw materials preparation and different conservation environments. The results show that the early strength and late strength of concrete based on seawater and sea sand are better than concrete based on freshwater and sand. There is no significant strength decreased for concrete based on seawater and sea sand under accelerated alternating wet and dry conditions. For concrete based on seawater and sea sand mixed with admixture, the downward trend of late strength is significantly delayed, the late strength of concrete based on the seawater and sea sand mixed with slag gets the most obvious growth trend, while the late strength of seawater and sea sand concrete mixed with fly ash gets the largest increment.
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Ren, Jia Guo, Qian Qian Wu, Zuo Zhen Han, Li Li i Qi Fang Wang. "Study on Hydro-Geochemical Action during Seawater Intrusion". Advanced Materials Research 468-471 (luty 2012): 2385–88. http://dx.doi.org/10.4028/www.scientific.net/amr.468-471.2385.
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On the basis of hydrogeology investigation, the groundwater, river water, seawater and the medium in the lower reaches of the Dagu River were collected respectively, their compositions and nature were determined, then the permeability and the regularity of the main ions were determined during simulating seawater intrusion with transfusion installment. Finally, hydro-geochemical action was studied with the numerical simulation method during seawater intrusion. The result indicts that the mineral dissolution and precipitation take place with ion exchanges, Calcite is in a supersaturated situation after the percent of seawater reaches 40％; the saturation index of Gypsum arises gradually at first, and then decreases after the peak, finally it increases again but it is always in unsaturated condition from beginning to the end.
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Pei, Qiang, Bangwen Cai, Zhicheng Xue, Yu Ding, Di Cui i Yun Guo. "Study on mechanical properties of corroded concrete columns strengthened with SMA wires". PLOS ONE 18, nr 2 (6.02.2023): e0276280. http://dx.doi.org/10.1371/journal.pone.0276280.
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Ocean crossing bridges suffer from seawater corrosion all year round and their mechanical properties will be substantially diminished. In order to enhance the mechanical properties of reinforced concrete columns corroded by seawater, SMA wire is used to restrain the reinforced concrete columns corroded by seawater to study their mechanical properties. 14 specimens were produced through the test, and the natural seawater corrosion was simulated by preparing a certain concentration of synthetic seawater. The mechanical properties of SMA strengthened specimens and unreinforced specimens are compared and analyzed, including failure mode, hysteresis curve, bearing capacity, ductility, stiffness and energy dissipation; the effects of different synthetic seawater corrosion concentrations on the mechanical properties of reinforced concrete columns are discussed. The results show that the bearing capacity and stiffness of reinforced concrete columns subjected to synthetic seawater corrosion are substantially diminished than those of uncorroded specimens, and the bearing capacity of specimens decreases more with the increase of synthetic seawater corrosion concentration; synthetic seawater corrosion has obscure effect on the ductility and energy dissipation performance of the specimens. The mechanical properties of the corroded specimens strengthened with SMA wire have been substantially enhanced, particularly the energy dissipation performance and bearing capacity have been notably enhanced, and the ductility and stiffness have also been somewhat enhanced. At the same time, based on the test, the finite element model is created according to the test specimen, while the accuracy of the model is verified, and the effects of the spacing and diameter of SMA wire, the strength of concrete and the thickness of protective layer on the mechanical properties of the specimen are analyzed.
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Zhu, Hongyi, Xingwei Li i Xianyou Zheng. "A Descriptive Study of Open Fractures Contaminated by Seawater: Infection, Pathogens, and Antibiotic Resistance". BioMed Research International 2017 (2017): 1–5. http://dx.doi.org/10.1155/2017/2796054.
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Aims. In this work, the main objectives were to investigate the clinical characteristics and bacterial spectrum present in open fractures contaminated by seawater. Methods. We conducted a retrospective cohort study and included all patients with open fractures from 1st January, 2012, to 31st December, 2015, in our hospital. Patients were grouped based on the presence of seawater contamination in wounds. We compared the infection rate, bacterial spectrum, and antibiotic resistance between the two groups. Results. We totally included 1337 cases of open fracture. Wounds from 107 cases (8.0%) were contaminated by seawater. The wound infection rate of seawater-contaminated group was significantly higher in patients with Gustilo-Anderson Type II and Type III open fractures. The bacterial spectrum from seawater-contaminated wounds was remarkably different from that of the remaining. Antibiotic sensitivity tests revealed that more than 90% of infecting pathogens in seawater-contaminated wounds were sensitive to levofloxacin and ciprofloxacin. Conclusion. Cephalosporin in combination with quinolone was recommended in the early-stage management of open fractures contaminated by seawater.
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Peng, Yu Feng, Shao Ge Yang, Li Li Zhao i Xin Yi Zhao. "Experimental Study on the Influence of Seawater Chemical Composition on the Laser Transmission Characteristics". Applied Mechanics and Materials 448-453 (październik 2013): 3717–20. http://dx.doi.org/10.4028/www.scientific.net/amm.448-453.3717.
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Marine development activities have a great impact on the Marine environment. Laser transmission has been widely used in marine communications and imaging technology. Due to the different proportion of the chemical composition of seawater in each Ocean field, the laser transmission characteristic in seawater is also different. The transmittance has been measured and calculated in a constant transmission distance in this experiment, by four different wavelength lasers and different concentrations of the various chemical components of the seawater. Then the data were analyzed by transmission curve fitting. The conclusion of this experiment is: for relatively pure seawater, the transmission characteristics of blue - green laser is better than the purple or red laser, and green laser transmission characteristics is better than blue laser; for larger impurities seawater such as Tianjin seawater, the transmission characteristics of red laser is better than the other three wavelength laser.
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Liu, Xin, Xue Qing Liu, Meng Li Chen, Li Ou i Bao Rong Hou. "Study on the Performance of Mg/Al Composite Anode". Advanced Materials Research 790 (wrzesień 2013): 98–101. http://dx.doi.org/10.4028/www.scientific.net/amr.790.98.
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The electrochemical performance of Mg-Al alloy composite sacrificial anodes in seawater was studied. The results show that Mg-Al composite anode can keep the electrochemical characters of Mg anode and Al anode respectively. The protection process of Mg-Al composite anode includes 4 steps: (1) Mg anode protects the steel, (2) interface oxides expose in seawater and anode performance decreases, (3) interface oxides dissolve in seawater and Al anode begins to work, (4) Al anode protects the steel efficiently.
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Abd-Elhamid, Hany F. "Investigation and control of seawater intrusion in the Eastern Nile Delta aquifer considering climate change". Water Supply 17, nr 2 (3.08.2016): 311–23. http://dx.doi.org/10.2166/ws.2016.129.
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Seawater intrusion is considered one of the main processes that degrade water quality by raising salinity. Over-pumping and decreasing recharge are considered the main causes of saltwater intrusion. Moreover, climate change and sea-level rise accelerate saltwater intrusion. In this paper SEAWAT code was used to study groundwater flow and seawater intrusion in the Eastern Nile Delta aquifer considering four scenarios of climate change including sea-level rise, increasing abstraction, decreasing recharge and the combination of these scenarios. The results showed that decreasing recharge has a significant effect on seawater intrusion. However, the combinations of these scenarios resulted in harmful intrusion and loss of groundwater. The soil salinity increased, which decreased agricultural production. The control of seawater intrusion and protection of groundwater resources and soil is very important. Different scenarios were implemented to protect the aquifer from seawater intrusion including decreasing abstraction, increasing recharge, abstracting brackish water and the combination of these three scenarios. The abstraction of brackish water gave a higher reduction of seawater intrusion and decreased groundwater table in the aquifer near the shore line, which protected the soil from salinity and increased agricultural production. However, the combination of these three scenarios gave the highest reduction of seawater intrusion.
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Li, Xiang Ran, Gang Han i Ri Jiang Cong. "A Study on Seawater Intrusion Prevention Measures and Comprehensive Governing Pattern". Applied Mechanics and Materials 170-173 (maj 2012): 2132–36. http://dx.doi.org/10.4028/www.scientific.net/amm.170-173.2132.
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The seawater intrusion is a kind of comparatively common natrual geological disaster around the coast area. In order to solve this sort of geological disaster, scholars both home and abroad have been doing quite a large amount of work to find out the cause of the disaster and the methods of its prevention. Among all of these work, the research of Yantai seawater intrusion comprehensive governance is one of the most typical. We take Yantai for instance, studying both engineering and management measures of the prevention of seawater intrusion, while at the same time exploring and discussing the pattern of the prevention of seawater intrusion by integrating "point, line and all the aspects" comprehensively, which produces quite outstanding results.
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Lu, Bangwen, Changwu Liu, Jungang Guo i Naiqi Feng. "Study on Physical and Mechanical Properties of High-Water Material Made by Seawater". Sustainability 15, nr 4 (11.02.2023): 3334. http://dx.doi.org/10.3390/su15043334.
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In maritime engineering, marine-derived construction materials are seen as an efficient and cost-effective alternative. HWM is a novel inorganic cementitious material characterized by its high water content, rapid setting, and early strengthening. In this study, first, HWM was proposed to be produced from seawater and used in a maritime environment. Two groups of HWM samples with varied w/c ratios were prepared with fresh water and seawater, and their behavior was examined to assess the viability of HWM produced with seawater. The microstructures and chemical compositions were studied using SEM and XRD. Results indicated that as the w/c ratio increased from 3:1 to 6:1, the water content, density, and uniaxial compressive strength of HWM produced from seawater varied from 72.1% to 77.5%; 1.25 to 1.12 g/cm3, and 1.47 MPa to 0.39 MPa, respectively, which is 2–10% lower, 0.8–2.2% higher, and 13–45% stronger than that from fresh water. The chemical composition of HWM mixed with seawater is predominantly composed of ettringite, C-S-H gel, aluminum (Al(OH)3) glue, M-S-H gel, and Mg(OH)2. SO42− and Mg2+ in seawater participate in the hydration and hardening of HWM, resulting in an increase in the synthesis of ettringite and M-S-H gel, which makes the skeletal structure of HWM denser, hence increasing its strength. HWM derived from seawater retains excellent physical and mechanical properties. This work reveals the HWM-seawater interaction mechanism, elucidates the promising application prospect of HWM in maritime engineering, and paves the way to investigate its field performance.
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He, Yuntao, Yongjun Liu, Chang Liu i Duan Li. "Analysis of Transmission Depth and Photon Number in Monte Carlo Simulation for Underwater Laser Transmission". Remote Sensing 14, nr 11 (27.05.2022): 2565. http://dx.doi.org/10.3390/rs14112565.
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The modeling of laser transmission characteristics in complex seawater is fundamental for bathymetric and oceanographic laser detection systems. Because the factors affecting laser transmission in seawater are independent of one another, firstly, in this paper, a Monte Carlo model of laser propagation in seawaters with suspended matter was established to study the influence of suspended matter with specific radius on the underwater laser transmission. Secondly, the influence of transmission depth and the number of photons on the laser extinction coefficients of seawater containing different concentrations of suspended matter were analyzed, respectively. Thirdly, the relationships between maximum transmission depth, the number of initial photons, and the concentrations were built and verified by simulations. Lastly, an experimental platform was set up and experiments were carried out to verify the Monte Carlo model and the relationships. Results show that (1) both the minimum initial photon number and maximum transmission depth depend exponentially on the concentrations of the suspended matter; (2) the extinction coefficients obtained by the Monte Carlo model and those obtained by experiments are consistent. The absolute values of the differences are less than 0.028 m−1, implying that (1) the proposed Monte Carlo model is effective for simulating laser propagation in seawaters with suspended matter; (2) the established relationships between maximum transmission depth, the minimum initial photon number, and the concentrations of suspended matter have better accuracies, which are valuable for the simulations on attenuation of laser transmission in seawater. The method of this paper can also be extended to the study of suspended solids with other radii and improve the simulation accuracy and decrease simulation time consumption.
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Xu, Zexuan, Bill X. Hu i Ming Ye. "Numerical modeling and sensitivity analysis of seawater intrusion in a dual-permeability coastal karst aquifer with conduit networks". Hydrology and Earth System Sciences 22, nr 1 (12.01.2018): 221–39. http://dx.doi.org/10.5194/hess-22-221-2018.
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Abstract. Long-distance seawater intrusion has been widely observed through the subsurface conduit system in coastal karst aquifers as a source of groundwater contaminant. In this study, seawater intrusion in a dual-permeability karst aquifer with conduit networks is studied by the two-dimensional density-dependent flow and transport SEAWAT model. Local and global sensitivity analyses are used to evaluate the impacts of boundary conditions and hydrological characteristics on modeling seawater intrusion in a karst aquifer, including hydraulic conductivity, effective porosity, specific storage, and dispersivity of the conduit network and of the porous medium. The local sensitivity analysis evaluates the parameters' sensitivities for modeling seawater intrusion, specifically in the Woodville Karst Plain (WKP). A more comprehensive interpretation of parameter sensitivities, including the nonlinear relationship between simulations and parameters, and/or parameter interactions, is addressed in the global sensitivity analysis. The conduit parameters and boundary conditions are important to the simulations in the porous medium because of the dynamical exchanges between the two systems. The sensitivity study indicates that salinity and head simulations in the karst features, such as the conduit system and submarine springs, are critical for understanding seawater intrusion in a coastal karst aquifer. The evaluation of hydraulic conductivity sensitivity in the continuum SEAWAT model may be biased since the conduit flow velocity is not accurately calculated by Darcy's equation as a function of head difference and hydraulic conductivity. In addition, dispersivity is no longer an important parameter in an advection-dominated karst aquifer with a conduit system, compared to the sensitivity results in a porous medium aquifer. In the end, the extents of seawater intrusion are quantitatively evaluated and measured under different scenarios with the variabilities of important parameters identified from sensitivity results, including salinity at the submarine spring with rainfall recharge, sea level rise, and a longer simulation time under an extended low rainfall period.
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Yusuf, Hamzah, Akhmad Azis, Sugiarto Badaruddin, Andi Muhammad Subhan Saiby, Zulvyah Faisal i Zubair Saing. "Physical modeling of sand columns application in recharge reservoir to prevent seawater intrusion". Water Supply 22, nr 2 (26.10.2021): 2170–78. http://dx.doi.org/10.2166/ws.2021.365.
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Abstract This study aims to provide visual evidence by the physical simulation to demonstrate the sand column performance of a recharge reservoir to control seawater encroachment and confirm some previous studies. In this analysis, a two-dimensional sand tank illustrates the sand column's role in overcoming seawater intrusion. Besides using dyes, the sand tank is also fitted with sensors to observe the length of seawater penetration. Furthermore, the simulation using SEAWAT numerical modeling is used as a reference in this analysis. The criteria analyzed were the number of sand columns, the reservoir water level, and the isochlors concentration. The results revealed a reasonably close match between physical and computational modeling. It was also found that the more sand columns and the higher the reservoir water level, resulted in the decrease of seawater penetration length that occurred. Physical and computational modeling findings indicated that the optimal results are derived using three sand columns with an RMSE value of 0.76. The seawater infiltration length decreased to 84.72% relative to sand column-free conditions at a reservoir water level of 15.0 cm.
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Su, Bao Wei, Yu Hong Wang i Xue Li Gao. "Pilot Study on Nanofiltration Seawater Softening for SWRO Desalination". Advanced Materials Research 550-553 (lipiec 2012): 2178–81. http://dx.doi.org/10.4028/www.scientific.net/amr.550-553.2178.
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Seawater desalination has long been recognized as an important method for the solution of the world fresh water shortage, especially seawater Reverse Osmosis (SWRO) desalination. Recently the issue is again being raised for the newly developed pretreatment technology using nanofiltration (NF) membrane which has special separation properties owing to the charge characteristics of its surface separation layer. In this study, two kinds of commercial NF membrane have been studied in a pilot UF-NF Integrated Membrane System (IMS). Operating conditions was investigated and the results show that NF can be effectively used for the softening of seawater and provide excellent feed for SWRO.
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Diao, Mengyao, Panlin Li, Weifang Ruan i Wanglin Li. "A Preliminary Study on The Prevention and Control of Seawater Intrusion in Northern Pingtan Island with Freshwater Recharge Curtain". E3S Web of Conferences 199 (2020): 00012. http://dx.doi.org/10.1051/e3sconf/202019900012.
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Seawater intrusion caused by groundwater over-exploitation is a kind of geological disaster caused by human economic activities and natural environment changes. Using freshwater recharge curtain technology is an effective means to prevent seawater intrusion. Based on the analysis of the characteristics of seawater intrusion in Pingtan island, Fujian Province, and in view of the possible seawater intrusion problems in the construction of Luyangpu underground reservoir in Pingtan Island, this paper expounds the basic principle of seawater intrusion prevention with freshwater recharge curtain , the technical measures of installing a row of recharge wells in the northern coastal zone of Luyangpu plain in Pingtan Island and using freshwater recharge curtain are put forward to prevent seawater intrusion. Through groundwater numerical simulation, the dynamic distribution of groundwater level in the north of Pingtan Island in the next 20 years is analyzed and predicted. The results show that the seawater intrusion can be effectively prevented by installing freshwater curtain recharge wells in the northern coast of Luyangpu.
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Delly, J., K. Mizuno, T. E. B. Soesilo i M. Gozan. "The Seawater Heavy Metal Content of the Mining Port Close to the Residential Area in the Morowali District". IOP Conference Series: Earth and Environmental Science 940, nr 1 (1.12.2021): 012019. http://dx.doi.org/10.1088/1755-1315/940/1/012019.
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Abstract Mining port operations are complex and can cause various forms of pollution. Analysis of seawater pollution from mining ports is required and complicated because of the various types of pollution, sources, effects, and different characteristics. This study examines the content of heavy metals in seawater in residential areas very close to mining ports. The method used sampling in three different places, examining seawater’s heavy metal properties. Secondary data of the quality of seawater was obtained from the results of data monitoring carried out by the company periodically since the port was built as a comparison material from the results of sample inspection. The results of this study indicate that the waters around the settlements contain heavy metals. The composition of Cd was 10%, Pb was125%, Cu was 625%, Ni was 760%, and Zn was 300% above the standard of seawater quality for the Port Area set by the Indonesian government, which did not match the yearly reports (secondary data). On the other hand, community activities also have a minor role as a source of pollution. Therefore, it is essential to do further research with a focus on finding sources of pollution.
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Abd-Elhamid, Hany, Akbar Javadi, Ismail Abdelaty i Mohsen Sherif. "Simulation of seawater intrusion in the Nile Delta aquifer under the conditions of climate change". Hydrology Research 47, nr 6 (4.01.2016): 1198–210. http://dx.doi.org/10.2166/nh.2016.157.
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The problem of seawater intrusion is encountered in almost all coastal aquifers. Because of its higher density, the seawater migrates inland into freshwater aquifers even without any pumping activities. Excessive pumping of groundwater would accelerate seawater intrusion. Climate change and sea level rise represent critical parameters affecting the rate and degree of seawater intrusion. In this paper, a coupled transient finite element model for simulation of fluid flow and solute transport in saturated and unsaturated soils (2D-FEST) is employed to study the seawater intrusion in the Nile Delta aquifer. The results of the current model are compared to results of SEAWAT for model verification. The (2D-FEST) model is used to investigate seawater intrusion considering the impacts of climate change. Three scenarios are studied: (a) rise in sea level, (b) decline of the piezometric head at the land side due to excessive pumping, and (c) combination of sea level rise and decline of the piezometric head. The results show that the rise in the sea level has a significant effect on the position of the transition zone. The third scenario represents the worst case under which the groundwater quality would deteriorate in large areas of the Nile Delta aquifer.
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Mastrocicco, Busico, Colombani, Vigliotti i Ruberti. "Modelling Actual and Future Seawater Intrusion in the Variconi Coastal Wetland (Italy) Due to Climate and Landscape Changes". Water 11, nr 7 (19.07.2019): 1502. http://dx.doi.org/10.3390/w11071502.
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Coastal freshwater resources are commonly under high risk of being contaminated from seawater. The main processes that affect seawater intrusion are groundwater overexploitation, land use change, and climate change effects. In this context coastal lagoons represent the more sensitive environments prone to seawater intrusion. Numerical modelling is a useful tool to understand and predict seawater intrusion. In this study, a three-dimensional SEAWAT model is employed to simulate the seawater intrusion to coastal aquifers of Variconi Oasis (Italy). The present simulation was divided into a calibration and a validation model, then the model was used to predict the salinization trend up to 2050. Results show the role of the sea in salinizing the beach front, while the retrodunal environment is characterized by transitional environments. Future seawater intrusion scenarios considering only climate data showed no significative differences in respect to the actual situation. The same happens considering also a low sea level rise prediction. On the contrary, the worst scenario (high sea level rise prediction), depicts a quite different situation, with a saline intrusion in the Variconi oasis that will severely affect the fragile transitional ecosystem. This modelling framework can be used to quantify the effects of climate changes in similar coastal environments.
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Wu, Huijun. "Study on mechanical properties of non-dispersible concrete in seawater environment". International Journal of Structural Integrity 11, nr 6 (20.12.2019): 809–18. http://dx.doi.org/10.1108/ijsi-07-2019-0069.
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Purpose The purpose of this paper is to research the hardened properties of non-dispersible concrete in seawater environment, especially in seawater environment. Design/methodology/approach The main approach is according to the experiment. Findings The findings of this paper are: first, because of the washing effect of water, the strength of underwater non-dispersible concrete is lower than that of terrestrial concrete. Second, the strength of non-dispersible underwater concrete with silica fume increases remarkably at different ages. Third, underwater non-dispersible concrete does not produce new products when it is formed and cured in seawater. Originality/value In this paper, underwater non-dispersible concrete is formed and maintained on land, freshwater and seawater by underwater pouring method. The working performance, mechanical properties and durability of underwater non-dispersible concrete mixtures after hardening are tested.
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Liu, Ning, Rui Zhang, Wen Yi Chen i Man Man Zhang. "Numerical Study of XCP Probe's Fluid Dynamic Characteristics". Applied Mechanics and Materials 130-134 (październik 2011): 1645–49. http://dx.doi.org/10.4028/www.scientific.net/amm.130-134.1645.
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Applied the finite volume method combining two-equations turbulence model,the influence of fluid dynamic characteristics on XCP probe under different factors be studied The fluid dynamic characteristics were researched under different influencing factors, such as falling speed, rotating rate,seawater density,etc. The drag coefficient under the different falling speeds and the limited velocity of submarine steady motion were obtained. Compared with the experimental results, the simulated results agree well with experimental results, the experiments have show the validity and feasibility of the numerical analysis method. These results will provide theory reference for selecting the reasonable rotating rate, analyzing stability and the movement rule of probe in the water, choosing suitable test parameters for XCP probe of different seawaters.
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Bao, Long Sheng, Xiao Fang Zhang, Ling Yu i Guang Shan Zhu. "Study on Solidification Mechanism of Chloride Salt in Base Course Material of Cement-Fly-ash-Flushed-by-Seawater". Advanced Materials Research 236-238 (maj 2011): 755–61. http://dx.doi.org/10.4028/www.scientific.net/amr.236-238.755.
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Through analyzing the influence of different slat content on the microstructure of cement and fly-ash-flushed-by-seawater binder, the solidification mechanism of salt added cement and fly-ash-flushed-by-seawater binder is investigated. The Scanning Electron Microscope test, X-Ray diffraction and theoretical analysis method are adopted to study the performance and the microstructure of cement and fly-ash-flushed-by-seawater, and to analyze the solidification mechanism of chloride in the mixture. When content of the chloride ions is added to the cement and fly-ash-flushed-by-seawater binder, a new kind of crystal-Friedel can be generated in the age of 7d and 28d. According to the unconfined strength test on the specimens which contain 0.5% chloride ions, the strength is high in 7d, highest in 28d. The chloride ions of the fly-ash-flushed-by-seawater can be solidified in the cement and fly-ash-flushed-by-seawater binder, which can increase the strength of the binder.
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Jingsheng, Chen, Tang Fei i Wang Feiyue. "Mobilization of Mercury from Estuarine Suspended Particulate Matter: A Case Study in the Yalujiang Estuary, Northeast China". Water Quality Research Journal 30, nr 1 (1.02.1995): 25–32. http://dx.doi.org/10.2166/wqrj.1995.005.
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Abstract Trace metal concentrations in suspended particulate matter in estuaries are dependent on the extent of mixing between river and seawater. Superimposed on this physical mixing, chemical mobilization from the particulates may take place. This paper presents the behavior of mercury in the Yalujiang estuary, northeast China. It deals with (i) field observations on the variations of mercury concentrations in the estuarine suspended material and (ii) the experimental mobilization of mercury from contaminated estuarine sediment by exposure to artificial seawater. Three stations on two cross sections in the upper and lower Yalujiang estuary were sampled over at least two or three complete tidal cycles. The field observations show that there is a clear mobilization of mercury from the suspended material during the maximum mixing of river and seawater. The experimental mobilization suggests that mobilization of mercury from the suspended particulates in seawater is caused not only by complexing with CI’ and ion-exchanging with the alkali and alkaline earth cations in seawater, but also by the dissolution of humic substances in the particles by seawater and the release of associated mercury.
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Harmesa, Harmesa, Lestari Lestari i Fitri Budiyanto. "Distribusi Logam Berat Dalam Air Laut Dan Sedimen Di Perairan Cimanuk, Jawa Barat, Indonesia". Oseanologi dan Limnologi di Indonesia 5, nr 1 (9.07.2020): 19. http://dx.doi.org/10.14203/oldi.2020.v5i1.310.
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<p><strong>Distribution of Heavy Metals in Seawater and Sediments in Cimanuk Estuary, West Java, Indonesia.</strong><strong> </strong>Increasing economic activities in the north coastal of Java have the potential to contribute to anthropogenic contaminants that threaten the water quality of Cimanuk coastal and estuary in Indramayu. Heavy metal which is one of the wastes from these activities has not been studied in detail. The aim of this study was to determine the distribution of Cu, Pb, Cd, Zn, and Ni in seawaters and sediments of the Cimanuk Estuary. Seawater and sediment samples were collected at 18 stations in May 2017. Seawater samples were extracted using the back extraction method while sediment samples were extracted using acids according to USEPA 3050B. Measurement of heavy metals from seawater extracts or sediments was carried out using Flame Absorption Spectrophotometry according to the USEPA 3050B method. The spatial distribution of heavy metals in seawater and sediments is modeled using ArcGIS® version 10.6.1. The results showed that ranges of metals in seawater : 0,0004 – 0,0038 mg/L (Cu), <0,0001 – 0,0044 mg/L (Pb), 0,0002 – 0,0003 mg/L (Cd), 0,0005 – 0,0119 mg/L (Zn), and 0,0020 – 0,0052 mg/L (Ni). While the metal content in sediments are 12,36 – 54,08 mg/kg (Cu), 6,43 – 15,72 mg/kg (Pb), 0,07 – 0,37 mg/kg (Cd), 64,53 – 85,16 mg/kg (Zn), and 19,66 – 62,85 mg/kg (Ni). Spatial distribution models show that heavy metals in seawater and sediments show identical patterns. High level of metals are generally detected at the stations located closed to the mainland, indicating that heavy metals are enrichment from terrestrial anthropogenic activities.</p>
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Che, You Ming, Hai Xing Hu i Xiao Qi Wan. "Study on the Impacts of Salinized Soils on the Quality of Upper Water during Seawater Intrusion". Applied Mechanics and Materials 623 (sierpień 2014): 290–94. http://dx.doi.org/10.4028/www.scientific.net/amm.623.290.
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Potential harm of environment caused by seawater intrusion had come into reality. Seawater intrusion has caused a variety of impacts on ecological environment. In this paper, in order to research salinized soils’ impacts on upper groundwater in the process of seawater intrusion, the author conducted a series of laboratory tests and analyzed characteristics of influence which lower salinized soils impact on upper water.
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Nie, Jing, i Shou Zhi Yi. "Study on the Cyclic Voltammetry Curve of Electrode in the Electrolytic Process of Seawater Pretreatment". Advanced Materials Research 1065-1069 (grudzień 2014): 3100–3104. http://dx.doi.org/10.4028/www.scientific.net/amr.1065-1069.3100.
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The performance of the electrode is the core technology of the electrolytic process of seawater pretreatment, and has the decisive influence on the systematic technological process and water quality. In the initial stage of electrolytic technology being applied in seawater pretreatment, soluble anodes, which use the aluminum, ferrum or other metal elements as the main ingredient, are chosen for most cases. And this method can effectively reduce the turbidity of raw seawater and sludge density index (SDI). While applying a variety of methods, the proportion of electrolytic aluminum, ferrum and other metal elements in the water can be effectively controlled. And this can increase the ratio of hydrolysate, but will also introduce the composition of soluble electrode into the seawater inevitably. This study uses electrodes which contain a variety of precious metal (such as Ti, Ru, and Ir) oxide in the seawater pretreatment process, which is different from traditional chlor-alkali industry.
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Ding, Kangkang, Penghui Zhang, Shaotong Liu, Lin Fan, Weimin Guo i Jian Hou. "Study on the classification of seawater corrosivity of typical sea areas in China". Corrosion Reviews 38, nr 4 (27.08.2020): 323–30. http://dx.doi.org/10.1515/corrrev-2020-0037.
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AbstractIn order to evaluate the seawater corrosivity of typical sea areas in China and provide guidance for the seawater corrosion protection on marine equipment and facilities, field exposure test was carried out. These typical sea areas under various climatic zones in China included Qingdao, Zhoushan, Sanya and a South China Sea reef, and Q235, copper, 5083 aluminum alloy and 304 stainless steel were chosen as test materials. The continuous monitoring of seawater environmental factors (temperature, salinity, pH, dissolved oxygen, etc.,) and the statistical work of first-year corrosion rates of test materials were done. Then, based on the metal corrosion rates method and the environmental factors method, the seawater corrosivity of these typical sea areas in China were classified, respectively. Furthermore, the classification results from the two methods were compared and analyzed.
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YAMAUCHI, Kazuhiko, Toshitsugu SAKOU i Hiromichi TANAKA. "FUNDAMENTAL EXPERIMENTAL STUDY ON DEEP SEAWATER OUTFALL". PROCEEDINGS OF CIVIL ENGINEERING IN THE OCEAN 16 (2000): 147–50. http://dx.doi.org/10.2208/prooe.16.147.
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FURUMAI, TAMOTSU, i RYUJI YOSHIDA. "Study on practical application of deep seawater". NIPPON SUISAN GAKKAISHI 76, nr 4 (2010): 726. http://dx.doi.org/10.2331/suisan.76.726.
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Dai, Ying Jie, Tian Zhu Li, Run Qing Yang, De Li Chen, Li Long Yan, Xiao Hui Wang i Ying Zhang. "Study on the Demonstration of Seawater Desalination". Advanced Materials Research 183-185 (styczeń 2011): 985–89. http://dx.doi.org/10.4028/www.scientific.net/amr.183-185.985.
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In this study, the marine circular economy mode of marine industries was investigated by using utilization of Tianjin Beijiang Power Plant. Tianjin Beijiang Power Plant, taking the effective and circular utilization of resources as core, depending on the regional industrial advantage, expanding the industrial chain continually and making itself play the leading role, perfectly combines sea water desalination, salt making, salt chemical products, building materials and some other items, thereby making the wastes of by-products of former processes the raw materials of latter processes. In this way, the power plant has found a new road of circular economy characterized by maximum resource utilization, minimum waste discharge and optimal economic benefit. The project meets the 3R rules of circular economy, i.e. “high efficiency, low consumption and low pollution”, and its project combining electric power, water and salt is first-ever in China and a typical circular economy project and an ecological project as well, presenting an important demonstration significance and promotion value for the comprehensive development of circular economy.
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Jovalekic, Nikola, Vujo Drndarevic, Ermanno Pietrosemoli i Iain Zennaro. "Experimental Study of LoRa Transmission over Seawater". Sensors 18, nr 9 (29.08.2018): 2853. http://dx.doi.org/10.3390/s18092853.
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Low Power Wide Area Networks (LPWANs) are gaining attention in both academia and industry by offering the possibility of connecting a large number of nodes over extended distances. LoRa is one of the technologies used as a physical layer in such networks. This paper investigates the LoRa links over seawater in two typical scenarios: clear Line-of-Sight (LOS) and obstructed path in two different Industrial, Scientific and Medical (ISM) radio bands: 868 MHz and 434 MHz. We used three different LoRa devices in the experiments: the Own Developed LoRa Transceiver (ODT) and two commercial transceivers. Firstly we investigated transceivers’ Receive Signal Strength Indicator (RSSI) and Signal-to-Noise (SNR) measurement chain linearity and provided correction factors for RSSI to correlate it with actual signal levels received at transceivers’ inputs. Next, we carried out field experiments for three different LoRa Spreading Factors, S F ∈ [ 7 , 10 , 12 ] , within a bandwidth of B W = 125 kHz and Coding Rate C R = 4 / 6 . The experiments showed that LoRa links are fully feasible over seawater at distances at least 22 km long, using only low-cost off-the-shelf rubber duck antennas in LOS path condition in both ISM bands. In addition, we showed that LoRa links can be established over 28 km obstructed LOS oversea path in ISM 434 MHz band, but using costly, higher gain antennas. Furthermore, the laboratory experiments revealed that RSSI is linear in a wide range, up to - 50 dBm, whereas the SNR measurement chain goes into saturation for Received Signal Strength (RSS) values higher than - 100 dBm. These findings enabled accurate interpretation of the results obtained in field experiments.
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Miller, Gary W., Chris A. Morgan, David J. Kieber, D. Whitney King, Julie A. Snow, Brian G. Heikes, Kenneth Mopper i James J. Kiddle. "Hydrogen peroxide method intercomparision study in seawater". Marine Chemistry 97, nr 1-2 (październik 2005): 4–13. http://dx.doi.org/10.1016/j.marchem.2005.07.001.
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Abou Rayan, M., i I. Khaled. "Seawater desalination by reverse osmosis (case study)". Desalination 153, nr 1-3 (luty 2003): 245–51. http://dx.doi.org/10.1016/s0011-9164(02)01143-8.
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Aly, G., A. Al-Haddad i M. Abdel-Jawad. "Parametric study on falling-film seawater desalination". Desalination 65 (listopad 1987): 43–55. http://dx.doi.org/10.1016/0011-9164(87)90122-6.
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Ahmed, AbdallaM, i Irving Moch. "Seawater reverse osmosis a study in use". Desalination 82, nr 1-3 (sierpień 1991): xx—xxi. http://dx.doi.org/10.1016/0011-9164(91)85167-s.
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Salem, Abdel Hameed M. "Study of Seawater Intrusion in Tajoura Area". مجلة علوم البحار والتقنيات البيئية 1, nr 2 (31.12.2015): 35–50. http://dx.doi.org/10.59743/jmset.v1i2.123.
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The aim of this study is to know the extent of seawater intrusion into groundwater. The geo-electrical method was used to measure the resistivity of subsurface layers. Field measurements were conducted using a resistivity device with a Schlumberger array. Variable electrodes were spread with a maximum distance of 400 m. Readings of 18 Vertical Electrical Soundings were taken in the area of study which has several wells that were formerly studied using chemical analysis method of well samples. Electrical data were analyzed and interpreted and horizontal and vertical sections of apparent resistivity were drawn, also contour maps of iso-resistivity lines were constructed. It has been clearly shown that seawater intruded into groundwater in the study area.
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Qin, Li Kun, Ling Xia Gao, Hong Wei Song i Xiu Wei Wang. "Experimental Study on Frost Resistance of Concrete in Seawater". Applied Mechanics and Materials 507 (styczeń 2014): 254–57. http://dx.doi.org/10.4028/www.scientific.net/amm.507.254.
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The experiments of concrete in seawater under 0, 25, 50, 75 and 100 freezing-thawing cycles were performed using fast freezing and thawing method. Appling large concrete static and dynamic triaxial test system, the influence of freezing and thawing cycles on compressive strength and strain at peak stress point of concrete in seawater were detected, and then simple mathematical expressions were established.
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Soto, Catalina, Norman Toro, Sandra Gallegos, Edelmira Gálvez, Aurora Robledo-Cabrera, Ricardo I. Jeldres, Matías Jeldres, Pedro Robles i Alejandro López-Valdivieso. "Study of Molybdenite Floatability: Effect of Clays and Seawater". Materials 15, nr 3 (1.02.2022): 1136. http://dx.doi.org/10.3390/ma15031136.
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Current challenges in froth flotation are the presence of complex gangues and the use of low-quality waters, such as seawater. In this scenario, the recovery of molybdenum minerals is difficult, mainly due to the hydrophobic faces’ physicochemical changes. In the present study, the natural floatability of pure molybdenite was analyzed by using microflotation assays, and hydrophobicity was measured by performing contact-angle measurements. The impact of two clays, kaolin (non-swelling) and Na-montmorillonite (swelling), was studied. The behavior in freshwater and seawater at pH 8 was compared, considering the current condition of the Cu/Mo mining industries, which use seawater in their operations. The presence of clays lowered the natural floatability of molybdenite precisely because they adhere to the surface and reduce its contact angle. However, the intensity with which they cause this phenomenon depends on the type of water and clay. Kaolin strongly adheres to the valuable mineral in both freshwater and seawater. For its part, Na-montmorillonite does it with greater intensity in a saline medium, but in freshwater, a high concentration of phyllosilicate is required to reduce the hydrophobicity of molybdenite. The clays’ adherence was validated by scanning electron microscopy (SEM) analysis.
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Li, Bao Guo, Xing Hua Tong, Yong Liu, Yan Gang Wang i Lin Sen Zhu. "Study on Corrosion Electrochemical Behavior of X42 and 16Mn Steel in Seawater". Applied Mechanics and Materials 364 (sierpień 2013): 599–602. http://dx.doi.org/10.4028/www.scientific.net/amm.364.599.
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In order to study the corrosion characteristics of 16Mn and X42 steel in natural seawater, the indoor contrast corrosion experiments are carried out in seawater by electrochemical method. Tafel polarization curves and electrochemical impedance spectroscopy (EIS) techniques are employed to investigate the corrosion electrochemical behavior of 16Mn and X42 steel, which are acquired by electrochemical workstation. The results of polarization curves and EIS reveal the respective corrosion rules of 16Mn and X42 steel in natural seawater. At last, the different influence of corrosion scale on the corrosion process of 16Mn and X42 steel is analyzed contrastively.
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WANG, Yajun, Chuhan ZHANG, Jinting WANG, Yanjie XU, Feng JIN, Youbo WANG, Qian YAN, Tao LIU, Xiaoqing GAN i Zhan XIONG. "Experimental Study on Foci Development in Mortar Using Seawater and Sand". Materials 12, nr 11 (3.06.2019): 1799. http://dx.doi.org/10.3390/ma12111799.
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Mortar using seawater and sand was the material studied here. The mortar specimens, in particular, were cured in natural seawater. The foci development in the mortar was the principal interest in this study. The on-line damage detection experiment art, including dynamically global MSHCT (Multi-Slices Helical Computer Tomography) scan and the local detection of EDS (Energy Dispersive Spectrometer), SEM (Scanning Electron Microscopy), and XRD (X-ray Diffraction) was designed to research the foci development in the mortar specimen. The mortar specimens with 70-day age were produced and investigated by the on-line damage detection experiments. The experiment results indicated that the mortar using seawater and sand offered appreciable strength at the early age, at least, although some saline minerals were generated during the preparation. The residual strength of the mortar was above 13 MPa, which helped to prevent the sharp damage of engineering bodies. The micro-interfacial behavior and the parental foci development controlled the damage evolution in the mortar using seawater and sand, the performance of which was still the adjustable one by composition optimization.
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Edward, Helfinalis i Y. Witasari. "The content of polycyclic aromatic hydrocarbon (PAHs) compound of seawater in Mayalibit Bay, West of Papua". IOP Conference Series: Earth and Environmental Science 1119, nr 1 (1.12.2022): 012089. http://dx.doi.org/10.1088/1755-1315/1119/1/012089.
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Abstract Polycyclic Aromatic Hydrocarbons (PAHs) are polycyclic aromatic organic compounds that contain several carbon and hydrogen rings, known to be toxic and can be harmful to human life and biota in marine waters. This study aimed to determine the levels of PAHs in seawater in Mayalibit Bay, Papua. Seawater samples were taken using a water sampler at 8 locations in Mayalibit Bay in November 2008. The contaminant content of organic carbon compounds in PAHs was determined by Gas-Chromatography Spectrometry and Mass Spectrometry (GCMS). The results showed a high content of HMW-PAHs and LMW-PAHs and passed the criteria for living status marine organisms by instruction of quality control guidelines by The Environment Ministry of Indonesia. The high molecular weight (HMW-PAHs) type has the highest rate, and LMW-PAH has the widest spread in Mayalibit’s seawaters, higher than Jakarta Bay, Timor Sea and Klabat Bay. The Diagnostic individual ratio analysis shows that the origin of PAHs in Mayalibit’s seawater comes from a pyrogenic source such as: residual petroleum and combustion products of organic matter.
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Edge, Billy L., i Roger S. Schlueter. "ENGINEERING STUDY FOR A NEW SEAWATER INTAKE SYSTEM". Coastal Engineering Proceedings 1, nr 21 (29.01.1988): 201. http://dx.doi.org/10.9753/icce.v21.201.
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Environmental assessment, engineering studies and designs were completed for a new 26.5 m3/s seawater intake system in the Persian Gulf. The original intake facility consisted of a curved, 60m breakwater with one end attached to the shoreline, a settling basin immediately adjacent to the shoreline and dredged to a maximum depth of approximately 5m, and a pumphouse structure located on shore such that the seaward wall formed one side of the settling basin. The facility located on an island in the Gulf, which served multiple seawater uses, had experienced both structural and operational problems, the latter consisting principally of excessive ingestion of sediment and seaweed. These factors plus the requirement for additional demands for seawater beyond plant capacity caused the owner to initiate a study of alternative intake systems, produce a design for the most effective solution and construct the new intake system.