Zeitschriftenartikel: „Carbonate pump“

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Silkin, Vladimir A., Oleg I. Podymov und Anna V. Lifanchuk. „Biological carbon pump in the Black Sea“. Hydrosphere Еcology (Экология гидросферы), Nr. 2(8) (Dezember 2022): 69–92. http://dx.doi.org/10.33624/2587-9367-2022-2(8)-69-92.

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In the northeastern part of the Black Sea, the biological carbon pump is represented by both organic and carbonate pumps. The organic carbon pump consists of small-cell diatoms (mainly Pseudo-nitzschia pseudodelicatissima) and large-cell diatoms (Pseudosolenia calcar-avis and Proboscia alata). The carbonate pump is represented by only one species of cococcolithophore, Emiliania huxleyi. These species form intense blooms that require characteristic hydrological and hydrochemical conditions. The seasonal dynamics of the biological carbon pump is as follows: organic pump (spring) → carbonate pump (late spring and early summer) → organic pump (summer and autumn). An exception is the long-term dynamics of carbon concentration, and no significant carbon growth trends have been identified. During the intensification of the work of the carbonate pump, partial concentrations of carbon in water, increased relative to the atmosphere, and an increased influence of the organic pump on high partial pressure are released. In late spring and early summer, CO2 is released in the Black Sea, as a result, absorption increases in summer. The carbonate pump arises with a greater arrival at sea.

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Pautova, Larisa A., und Vladimir A. Silkin. „Biological carbon pump in the ocean and phytoplankton structure“. Hydrosphere Еcology (Экология гидросферы), Nr. 1(3) (2019): 1–12. http://dx.doi.org/10.33624/2587-9367-2019-1(3)-1-12.

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The process of carbon transfer from the atmosphere to the ocean floor is determined by three different pumps in nature: a solubility pump, an organic pump and a carbonate pump. The latter two are of biological nature. Phytoplankton is a key mediator of organic and carbonate pumps. Depending on its structure, either an organic pump or a carbonate pump will dominate. The structure of the phytoplankton community is formed depending on the hydrophysical and hydrochemical conditions in the ocean. An important regulator of a biological carbon pump is the intensity of the processes in the carbon cycle, operating in the photic zone. The degree of closure of this cycle depends on the structure of the food chain. The increasing complexity of the food chain by adding organisms of high trophic levels reduces the efficiency of the carbon pump. Conversely, the simplification of such a structure increases the flow of organic carbon to the ocean floor.

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J.P, GUPTA, SUMBRIA N.M und KHANNA Y.P. „QUALITY OF DIFFERENT SOURCES OF IRRIGATION WATER OF JAMMU REGION“. Madras Agricultural Journal 85, February (1998): 110–12. http://dx.doi.org/10.29321/maj.10.a00694.

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Water samples from different sources viz., rivers, streams, nallahs, tube wells and hand pumps in Jammu region were collected and analysed for quality parameters to ascertain their suitability for imigation purposes. Except some of the tubewell and hand pump water samples which showed higher values of residual sodium carbonate, most of the water sources were observed to he suitable for irrigation purposes.

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Cerclet, Léo, Benoît Courcelles und Philippe Pasquier. „Impact of Standing Column Well Operation on Carbonate Scaling“. Water 12, Nr. 8 (07.08.2020): 2222. http://dx.doi.org/10.3390/w12082222.

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Standing column well constitutes a recent promising solution to provide heating or cooling and to reduce greenhouse gases emissions in urban areas. Nevertheless, scaling issues can emerge in presence of carbonates and impact their efficiency. Even though a thermo-hydro-geochemical model demonstrated the impact of the water temperature on carbonate concentration, this conclusion has not been yet demonstrated by field investigations. To do so, an experimental ground source heat pump system connected to a standing column well was operated under various conditions to collect 50 groundwater samples over a period of 267 days. These field samples were used for mineral analysis and laboratory batch experiments. The results were analyzed with multivariate regression and geochemical simulations and confirmed a clear relationship between the calcium concentrations measured in the well, the temperature and the calcite equilibrium constant. It was also found that operating a ground source heat pump system in conjunction with a small groundwater treatment system allows reduction of calcium concentration in the well, while shutting down the system leads to a quite rapid increase at a level consistent with the regional calcium concentration. Although no major clogging or biofouling problem was observed after two years of operation, mineral scales made of carbonates precipitated on a flowmeter and hindered its operation. The paper provides insight on the impact of standing column well on groundwater quality and suggests some mitigation measures.

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Guo, Liyu, und Wenju Shan. „Water Source Heat Pump’s Stuck Problems and Solutions“. Journal of Physics: Conference Series 2174, Nr. 1 (01.01.2022): 012084. http://dx.doi.org/10.1088/1742-6596/2174/1/012084.

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Abstract This paper analyses the water source heat pump’s normal stuck reasons, and test each of them. Identify the main reasons of the stuck pump is pump mechanical seal dynamic ring and static ring binding problems. (Poor water quality, water calcium carbonate, magnesium carbonate grind through the dynamic and static ring, after a long time stop, static ring long force extrusion contact, static ring binding surface molecular diffusion migration adhesion), due to the two rings’ binding, rotating torque beyond the motor starting torque, make the motor can’t start normally. This paper aims to find the real cause of the dynamic ring absorption, and put forward subsequent rectification measures to prevent recurrent stuck.

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Gao, Qing He, Yi Can Wang und Yu Mei Jiang. „Study on Scaling Formation Characteristics and Produced Liquid Properties in Oil-Wells of ASP Flooding“. Advanced Materials Research 524-527 (Mai 2012): 1270–78. http://dx.doi.org/10.4028/www.scientific.net/amr.524-527.1270.

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Strong base ASP flooding technology can improve oil recovery by 20%, but the lifting system exists serious scaling problems which cause pump detection period shorter. The main composition of the scale are organisms (heavy oil is in majority), carbonates and silicates. The content of each component is closely related to pH value. With high pH value, the main composition of the scale is silicate. With low pH value, the main composition of the scale is carbonate. The results of analysis of the relationship between scale composition, scaling position and depositional sequence showed that the content of silicate gradually increased from top to down in shaft while the carbonate decreased. In the process of scale deposition, carbonate scale emerged at first and then it provided attachment points and crystal nucleus for the silicate. The rough surface of carbonate scale increased the friction between the fluid and the wall, it promoted the formation of silicate. Statistically analyze the properties of pH value, alkalinity, calcium, magnesium, silicon, polymer, viscosity, surfactant, fluid yield, water content in produced liquid and their influences on scaling in the injection-production period. Establish the prediction basis using the pH value as primary and ion content as supplement for the problems of mechanical production well scaling. In the period of carbonate scaling (pH10.5), the process slowed down. The coincidence rate was 93.9% after pilot tests. It provided a basis for taking corresponding measures to inhibit scale formation.

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Matsumura, Yukihiko, und Kunio Yoshida. „Heat pump characteristics of sodium carbonate dehydration/hydration system“. International Journal of Energy Research 19, Nr. 3 (April 1995): 253–61. http://dx.doi.org/10.1002/er.4440190309.

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Planchat, Alban, Laurent Bopp, Lester Kwiatkowski und Olivier Torres. „The carbonate pump feedback on alkalinity and the carbon cycle in the 21st century and beyond“. Earth System Dynamics 15, Nr. 3 (03.05.2024): 565–88. http://dx.doi.org/10.5194/esd-15-565-2024.

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Abstract. Ocean acidification is likely to impact all stages of the ocean carbonate pump, i.e. the production, export, dissolution and burial of biogenic CaCO3. However, the associated feedback on anthropogenic carbon uptake and ocean acidification has received little attention. It has previously been shown that Earth system model (ESM) carbonate pump parameterizations can affect and drive biases in the representation of ocean alkalinity, which is critical to the uptake of atmospheric carbon and provides buffering capacity towards associated acidification. In the sixth phase of the Coupled Model Intercomparison Project (CMIP6), we show divergent responses of CaCO3 export at 100 m this century, with anomalies by 2100 ranging from −74 % to +23 % under a high-emission scenario. The greatest export declines are projected by ESMs that consider pelagic CaCO3 production to depend on the local calcite/aragonite saturation state. Despite the potential effects of other processes on alkalinity, there is a robust negative correlation between anomalies in CaCO3 export and salinity-normalized surface alkalinity across the CMIP6 ensemble. Motivated by this relationship and the uncertainty in CaCO3 export projections across ESMs, we perform idealized simulations with an ocean biogeochemical model and confirm a limited impact of carbonate pump anomalies on 21st century ocean carbon uptake and acidification. However, we highlight a potentially abrupt shift, between 2100 and 2300, in the dissolution of CaCO3 from deep to subsurface waters when the global-scale mean calcite saturation state reaches about 1.23 at 500 m (likely when atmospheric CO2 reaches 900–1100 ppm). During this shift, upper ocean acidification due to anthropogenic carbon uptake induces deep ocean acidification driven by a substantial reduction in CaCO3 deep dissolution following its decreased export at depth. Although the effect of a diminished carbonate pump on global ocean carbon uptake and surface ocean acidification remains limited until 2300, it can have a large impact on regional air–sea carbon fluxes, particularly in the Southern Ocean.

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Salmon, K. H., P. Anand, P. F. Sexton und M. Conte. „Upper ocean mixing controls the seasonality of planktonic foraminifer fluxes and associated strength of the carbonate pump in the oligotrophic North Atlantic“. Biogeosciences Discussions 11, Nr. 8 (12.08.2014): 12223–54. http://dx.doi.org/10.5194/bgd-11-12223-2014.

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Abstract. Oligotrophic regions represent up to 75% of Earth's open-ocean environments, and are typically characterized by nutrient-limited upper-ocean mixed layers. They are thus areas of major importance in understanding the plankton community dynamics and biogeochemical fluxes. Here we present fluxes of total planktonic foraminifera and eleven planktonic foraminifer species from a bi-weekly sediment trap time series in the oligotrophic Sargasso Sea, subtropical western North Atlantic Ocean at 1500 m water depth, over two ∼2.5 year intervals, 1998–2000 and 2007–2010. Foraminifera flux was closely correlated with total mass flux and with carbonate and organic carbon fluxes. We show that the planktonic foraminifera flux increases approximately five-fold during the winter–spring, contributing up to ∼40% of the total carbonate flux, driven primarily by increased fluxes of deeper dwelling ("globorotaliid") species. Interannual variability in total foraminifera flux, and in particular fluxes of the deep dwelling Globorotalia truncatulinoides, Globorotalia hirsuta, Globorotalia inflata, were related to differences in seasonal mixed layer dynamics affecting the strength of the spring phytoplankton bloom and export flux, and by the passage of mesoscale eddies. The heavily calcified, dense carbonate tests of deeper dwelling species (3 times denser than surface dwellers) can contribute up to 90% of the foraminiferal-derived carbonate in this region during late winter-early spring, implying a high seasonality of the biological carbonate pump in oligotrophic oceanic regions. Our data suggest that climate cycles, such as the North Atlantic Oscillation, that modulate the depth of the mixed layer, intensity of nutrient upwelling and primary production could also modulate the strength of the biological carbonate pump in the oligotrophic North Atlantic.

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Guo, Yintong, Peng Deng, Chunhe Yang, Xin Chang, Lei Wang und Jun Zhou. „Experimental Investigation on Hydraulic Fracture Propagation of Carbonate Rocks under Different Fracturing Fluids“. Energies 11, Nr. 12 (15.12.2018): 3502. http://dx.doi.org/10.3390/en11123502.

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Deep carbonate reservoirs are rich in oil and gas resources. However, due to poor pore connectivity and low permeability, it is necessary to adopt hydraulic fracturing technology for their development. The mechanism of hydraulic fracturing for fracture initiation and propagation in carbonate rocks remains unclear, especially with regard to selection of the type of fracturing fluid and the fracturing parameters. In this article, an experimental study focusing on the mechanisms of hydraulic fracturing fracture initiation and propagation is discussed. Several factors were studied, including the type of injecting fracturing fluids, pump flow rate, fracturing pressure curve characteristics, and fracture morphology. The results showed the following: (1) The viscosity of fracturing fluid had a significant effect on fracturing breakdown pressure. Under the same pump flow rate, the fracturing breakdown pressure of slick water was the lowest. Fracturing fluids with low viscosity could easily activate weakly natural fractures or filled fractures, leading to open microcracks, and could effectively reduce the fracturing breakdown pressure. (2) The fluctuations in fracturing pump pressure corresponded with the acoustic emission hits and changes in radial strain; for every drop of fracturing pressure, acoustic emission hits and changes in radial strain were mutated. (3) Under the same fracturing fluid, the pump flow rate mainly affected fracturing breakdown pressure and had little effect on fracture morphology. (4) The width of the main fracture was affected by the viscosity and pump flow rate. Maximum changes in radial strain at the fracturing breakdown pressure point occurred when the fracturing fluid was guar gum. (5) With gelled acid and cross-linked acid fracturing, the main fractures were observed on the surface. The extension of the fracturing crack was mainly focused near the crack initiation parts. The crack expanded asymmetrically; the wormhole was dissolved to break through to the surface of the specimen. (6) The dissolution of gelled acid solution could increase the width of the fracturing crack and improve the conductivity of carbonate reservoirs.

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Bybee, Karen. „A Pump-Aided Reverse-Dump-Flood Technique for Carbonate Reservoirs“. Journal of Petroleum Technology 52, Nr. 01 (01.01.2000): 41–45. http://dx.doi.org/10.2118/0100-0041-jpt.

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12

Dogru, A. H., A. A. Hamoud und S. G. Barlow. „Multiphase Pump Recovers More Oil in a Mature Carbonate Reservoir“. Journal of Petroleum Technology 56, Nr. 02 (01.02.2004): 64–67. http://dx.doi.org/10.2118/83910-jpt.

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13

Salmon, K. H., P. Anand, P. F. Sexton und M. Conte. „Upper ocean mixing controls the seasonality of planktonic foraminifer fluxes and associated strength of the carbonate pump in the oligotrophic North Atlantic“. Biogeosciences 12, Nr. 1 (13.01.2015): 223–35. http://dx.doi.org/10.5194/bg-12-223-2015.

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Abstract. Oligotrophic regions represent up to 75% of Earth's open-ocean environments. They are thus areas of major importance in understanding the plankton community dynamics and biogeochemical fluxes. Here we present fluxes of total planktonic foraminifera and 11 planktonic foraminifer species measured at the Oceanic Flux Program (OFP) time series site in the oligotrophic Sargasso Sea, subtropical western North Atlantic Ocean. Foraminifera flux was measured at 1500 m water depth, over two ~ 2.5-year intervals: 1998–2000 and 2007–2010. We find that foraminifera flux was closely correlated with total mass flux, carbonate and organic carbon fluxes. We show that the planktonic foraminifera flux increases approximately 5-fold during the winter–spring, contributing up to ~ 40% of the total carbonate flux. This was primarily driven by increased fluxes of deeper-dwelling globorotaliid species, which contributed up to 90% of the foraminiferal-derived carbonate during late winter–early spring. Interannual variability in total foraminifera flux, and in particular fluxes of the deep-dwelling species (Globorotalia truncatulinoides, Globorotalia hirsuta and Globorotalia inflata), was related to differences in seasonal mixed layer dynamics affecting the strength of the spring phytoplankton bloom and export flux, and by the passage of mesoscale eddies. As these heavily calcified, dense carbonate tests of deeper-dwelling species (3 times denser than surface dwellers) have greater sinking rates, this implies a high seasonality of the biological carbonate pump in oligotrophic oceanic regions. Our data suggest that climate cycles, such as the North Atlantic Oscillation, which modulates nutrient supply into the euphotic zone and the strength of the spring bloom, may also in turn modulate the production and flux of these heavily calcified deep-dwelling foraminifera by increasing their food supply, thereby intensifying the biological carbonate pump.

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Cornuault, Pauline, Thomas Westerhold, Heiko Pälike, Torsten Bickert, Karl-Heinz Baumann und Michal Kucera. „Nature and origin of variations in pelagic carbonate production in the tropical ocean since the mid-Miocene (ODP Site 927)“. Biogeosciences 20, Nr. 3 (06.02.2023): 597–618. http://dx.doi.org/10.5194/bg-20-597-2023.

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Abstract. Marine plankton is an important component of the global carbon cycle. Whereas the production and seafloor export of organic carbon produced by the plankton, the biological pump, has received much attention, the long-term variability in plankton calcification, controlling the carbonate counter pump, remains less well understood. However, it has been shown that changes in pelagic calcification (biological compensation) could affect the ocean's buffering capacity and thus regulate global carbon budget on geological timescales. Here we use Neogene pelagic sediments deposited on the Ceara Rise in the tropical Atlantic to characterize the variability in pelagic carbonate production with a focus on warm climates. A re-evaluation of published records of carbonate accumulation at the Ceara Rise reveals a systematic increase in sedimentation rates since the late Miocene, but the carbonate accumulation rate does not show a clear trend. Instead, we observe substantial orbital timescale variability in carbonate accumulation, combined with a trend towards less carbonate on average at sites located below 4 km, likely due to the effect of carbonate dissolution. To evaluate long-term changes against possible orbital-scale variability, we generated new high-resolution records of carbonate accumulation rate at Ocean Drilling Program (ODP) Site 927 across two Quaternary interglacials (MIS 5 and MIS 9), the Pliocene warm period (MIS KM5) and the Miocene Climatic Optimum (MCO). We observe that the highest carbonate accumulation rates occurred during the Pliocene but that each of the studied intervals was characterized by large-magnitude orbital variability. Prominent variations in carbonate accumulation prior to the Quaternary preservation cycles appear to follow Earth obliquity and eccentricity. These results imply that pelagic carbonate accumulation in the tropical ocean, buffered from large temperature changes, varied on orbital timescales. The magnitude of the orbital-scale variability was similar or even higher than the long-term mean differences among the studied intervals. Since preservation can be excluded as a driver of these changes prior to the Quaternary, the observed variations must reflect changes in the export flux of pelagic biogenic carbonate. We conclude that the overall carbonate production by pelagic calcifiers responded to local changes in light, temperature, and nutrients delivered by upwelling, which followed long orbital cycles, as well as to long-term shifts in climate and/or ocean chemistry. The inferred changes on both timescales were sufficiently large such that when extrapolated on a global scale, they could have played a role in the regulation of the carbon cycle and global climate evolution during the transition from the Miocene warm climates into the Quaternary icehouse.

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Zheng, Heng, Ning Cheng, Zhong Wei Cao, Wen Ting Lu und Jun Sheng Sun. „Study on the Stimulated Reservoir Volume Technology in Tight Carbonate Reservoir“. Advanced Materials Research 1051 (Oktober 2014): 77–80. http://dx.doi.org/10.4028/www.scientific.net/amr.1051.77.

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In the development of carbonate reservoir, it usually uses acid fracturing to improve the production. Because of the limitation of, the production rates from the wells are very low. Based on the “stimulated reservoir volume” which is used in the development of unconventional reservoirs, combined with the characteristics of tight carbonate reservoirs, in the early stage with low viscosity liquid, large pump scheme, small size proppant and pulse type sand to form complex fracture network. In the later, with high viscosity liquid, high sand rate, large size proppant, and continuous type sand to enlarge the stimulated volume and conductivity. Based on the experimental evaluation, the fracture design was optimized, and it will provide a reference for the stimulation of tight carbonate reservoir.

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Ahmad, Azhar, und Rodney Dathan. „Milk-Alkali Syndrome: An Unusual Cause of Acute Renal Failure“. Acute Medicine Journal 2, Nr. 2 (01.04.2003): 64–65. http://dx.doi.org/10.52964/amja.0045.

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Milk–alkali syndrome is described as a triad of hypercalcaemia, metabolic alkalosis and renal impairment, resulting from the ingestion of calcium and absorbable alkali1. It was more common in the early part of the century when antacids were used for the symptomatic treatment of peptic ulcer disease. The use of antacids has since been overtaken by H2- receptor antagonists and proton pump inhibitors. More recently, there have been various case reports of milk-alkali syndrome due to the increasing use of calcium carbonate as part of the management of osteoporosis and chronic renal failure, and also the increasing availability of calcium carbonate ‘over the counter’. We describe a case of milk-alkali syndrome due to self-medication with calcium carbonate.

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NourBaniYounes, Mohd, Salah Abu-Ruz, Azzat Alawwa, Mai Mohammad Alfalahat, Taghreed A. Al-Refai und Jaafar Abu Abeeleh. „THE EFFECTS OF CALCIUMCARBONATE/MAGNESIUM CARBONATE COMBINATION CHEWABLE TABLETS IN COMPARISON TO CALCIUM CARBONATE TABLETS ON PHOSPHATE BINDING IN HEMODIALYSIS PATIENTS WHO ARE TAKING PROTON PUMP INHIBITORS“. INDIAN RESEARCH JOURNAL OF PHARMACY AND SCIENCE 4, Nr. 2 (Juni 2017): 1051–62. http://dx.doi.org/10.21276/irjps.2017.4.2.14.

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Povarov, Vladimir P., Dmitry B. Statsura und Dmitry Ye Usachev. „Operating experience and ways to improve the performance of the service water supply system at the Novovoronezh NPP II (Units 1 and 2)“. Nuclear Energy and Technology 6, Nr. 4 (20.11.2020): 253–60. http://dx.doi.org/10.3897/nucet.6.60461.

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The operating experience of Novovoronezh NPP II-1 shows that, in the summer period, the temperature of the cooling water exceeds the design value: this indicates the insufficient performance of the service water supply system. The main factor that has a negative impact on the performance of this system is the formation of carbonate deposits on the cooling tower filler. At Novovoronezh NPP II-1, the cooling tower water distribution system was cleaned from carbonate deposits by the method of combined vibration and aerohydraulic impact. The tested method of cleaning the filler cannot be considered optimal, since the main stage that determines the entire cleaning duration is the assembly/disassembly of the cooling tower filler. It is necessary to continue research on the choice of a strategy for controlling the carbonate deposition rate, taking into account the revealed influence of the design features of the main cooling water pipelines and pipelines of the cooling tower water distribution system on the mechanism of deposit formation in the peripheral spraying area. As compensating measures to ensure the required temperature regime of the turbine plant equipment at Novovoronezh NPP II-1, it is practiced during the summer period to put the standby heat exchangers of the lubrication system and the standby pump of the nonessential services cooling water system into parallel operation. This solution is fraught with the risk of an unplanned decrease in the electrical load if this equipment is turned off in the event of a malfunction. To increase the operating stability of Novovoronezh NPP II-1 and -2 in the summer period, it is proposed to carry out a number of measures aimed at mitigating the negative consequences caused by the elevated service water temperature. Equipment upgrade options are evaluated, e.g., by installing an additional pump for the turbine building services cooling system and (or) laying an additional pipeline to supply part of the makeup water from the Don River directly to the suction pipelines of the pumps of the turbine building services cooling system.

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Carpenter, Chris. „Combined Mud-Cooling, MPD Techniques Enable HP/HT Drilling in Egypt“. Journal of Petroleum Technology 75, Nr. 03 (01.03.2023): 79–82. http://dx.doi.org/10.2118/0323-0079-jpt.

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_ This article, written by JPT Technology Editor Chris Carpenter, contains highlights of paper SPE 210252, “Drilling the Deepest HP/HT Onshore Exploration Well Using a Combination of Mud-Cooling and MPD Techniques: A Field Case Study From the Nile Delta of Egypt Targeting a Mesozoic Carbonate Platform,” by Mahmoud El-Husseiny, Egyptian Natural Gas Holding Company, and Taher Elfakharany, Al-Azhar University. The paper has not been peer reviewed. _ The complete paper reviews the successful application of a mud-cooling and managed-pressure-drilling (MPD) system in a high-pressure/high-temperature (HP/HT) well to explore the potential of the Mesozoic carbonate platform with a pressure ramp and narrow mud-weight window (NMWW) in the Nile Delta. The constant bottomhole pressure (CBHP) variation of MPD in combination with mud cooling was used to drill from the middle of the pressure ramp to the target depth, maintaining the mud-inlet temperature at approximately 50°C. Geological Targets and Geohazards The primary objective of Well T-1 is the edge of a Mesozoic carbonate platform. These carbonates are expected to be high-energy shallow marine deposits with fair reservoir properties (20–50% net-to-gross, 5–10% porosity). The secondary objectives are turbiditic sandstone channels of the Oligocene. These sandstones are expected to have 9–20% porosity and 50–300 md permeability. Potential Middle and Late Miocene geohazards include pressure rampup associated with losses, kicks, and borehole degradation, including tight holes, overpull, and caves; and reported sticking and hangup events. The HP domain begins below approximately 4000 m. Potential Oligocene to Paleocene geohazards include NMWWs associated with losses, kicks, and simultaneous gains and losses (ballooning); borehole degradation, including tight holes, overpull, and caves; and sticking and hangup events. The HP and HT domains begin below approximately 4500 m. Potential Mesozoic carbonate geohazards include possible losses of fractured and pressure-regressed carbonates. Mud-Cooling Technique Concept and Equipment The mud cooler consists of two circuits. In the first, hot mud is circulated through a dual mud cooler using a centrifugal pump. Because of heat exchange through the plate heat exchanger, the mud is cooled and transferred back into the active mud system. The discharge of cold mud takes place upstream of the point where the suction of hot mud occurs. In the second circuit, a fluid mixed with water and glycol is circulated between a dual air cooler and the dual mud cooler using a dedicated pump. When passing through the plate heat exchanger, this mixture of water and glycol is evacuated. When this mixture returns to the dual air cooler, it is cooled using high-performance ventilators. The mud-cooling system features 16 ventilators. The efficiency of the mud-cooling system is adjusted with a number of operated ventilators. The mud-cooling units used in this well consist of two dry air coolers and two sets of air fans (Fig. 1), with each set containing 24 fans. A mixture of 10% glycol and water was used as a cooling fluid.

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LIU, Zhifei. „Calcium carbonate pump during Quaternary glacial cycles in the South China Sea“. Chinese Science Bulletin 48, Nr. 17 (2003): 1862. http://dx.doi.org/10.1360/02wd0336.

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Liu, Zhifei, Jian Xu, Jun Tian und Pinxian Wang. „Calcium carbonate pump during Quaternary glacial cycles in the South China Sea“. Chinese Science Bulletin 48, Nr. 17 (September 2003): 1862–69. http://dx.doi.org/10.1007/bf03184069.

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Cickaric, Dragana, Ivana Dersek-Timotic, Antonije Onjia und Ljubinka Rajakovic. „Development of ion chromatography methods for the determination of trace anions in ultra pure water from power plants“. Journal of the Serbian Chemical Society 70, Nr. 7 (2005): 995–1003. http://dx.doi.org/10.2298/jsc0507995c.

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A suppressed ion chromatography (IC) technique, using a carbonate/hydrogen carbonate or a hydroxide eluent, has been evaluated as a monitoring tool for the detection of major anions (F-, Cl-, NO3-, PO43- and SO42-) in ultra pure water and condensed steam from thermal power plants. An electrical conductivity detector with an anion-exchange column (IonPac AS14), an auto self-regenerating suppressor (ASRS), and an isocratic high-pressure pump system were used for the detection of low concentrations of inorganic anions. It was shown that the suppressed IC technique provides a suitable means for preventing possible damage to generating equipment in power plants. The detection limits of the method for the anions of interest were < 0.3 ?g/L.

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Nagy, Brigitte, und Andrea Kustermann. „Rehabilitation of Porous Building Components and Masonry by MICP Injection Method“. Buildings 13, Nr. 5 (13.05.2023): 1273. http://dx.doi.org/10.3390/buildings13051273.

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Microbial-induced calcium carbonate precipitation (MICP) is a novel approach that is already being applied in various areas of construction. The precipitated calcium carbonate can be used to reduce porosity and thus increase the durability of deteriorated building components. This study investigates whether MICP injections are suitable for building rehabilitation. Porous mortar test samples of recycled aggregate and parts of deteriorated masonry were prepared. The MICP injections were performed without pressure and with an injection pump. The treatment effect was investigated after MICP injection by testing the porosity, strength and microscopic evaluation. It can be observed that multiple MICP injections under pressure result in a reduction of the pore volume of porous mortar samples. The produced calcium carbonate precipitates in the pore space of the samples and increases the density by 1.59% and the weight by 7.56%, which also results in a 48.3% reduction of the capillary water absorption. The results of strength tests show an increase of 45.16% in flexural strength and 35.64% in compressive strength compared with the untreated mortar samples. In addition, the MICP process was investigated and the precipitation was characterised. The X-ray diffraction (XRD) of the precipitated calcium carbonate confirms that mainly calcite was formed, which was also found in the pore structure of the MICP-injected masonry after the microscopic analysis. Precipitated calcium carbonate could be detected especially near the injection spots.

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Planchat, Alban, Lester Kwiatkowski, Laurent Bopp, Olivier Torres, James R. Christian, Momme Butenschön, Tomas Lovato et al. „The representation of alkalinity and the carbonate pump from CMIP5 to CMIP6 Earth system models and implications for the carbon cycle“. Biogeosciences 20, Nr. 7 (03.04.2023): 1195–257. http://dx.doi.org/10.5194/bg-20-1195-2023.

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Abstract. Ocean alkalinity is critical to the uptake of atmospheric carbon in surface waters and provides buffering capacity towards the associated acidification. However, unlike dissolved inorganic carbon (DIC), alkalinity is not directly impacted by anthropogenic carbon emissions. Within the context of projections of future ocean carbon uptake and potential ecosystem impacts, especially through Coupled Model Intercomparison Projects (CMIPs), the representation of alkalinity and the main driver of its distribution in the ocean interior, the calcium carbonate cycle, have often been overlooked. Here we track the changes from CMIP5 to CMIP6 with respect to the Earth system model (ESM) representation of alkalinity and the carbonate pump which depletes the surface ocean in alkalinity through biological production of calcium carbonate and releases it at depth through export and dissolution. We report an improvement in the representation of alkalinity in CMIP6 ESMs relative to those in CMIP5, with CMIP6 ESMs simulating lower surface alkalinity concentrations, an increased meridional surface gradient and an enhanced global vertical gradient. This improvement can be explained in part by an increase in calcium carbonate (CaCO3) production for some ESMs, which redistributes alkalinity at the surface and strengthens its vertical gradient in the water column. We were able to constrain a particulate inorganic carbon (PIC) export estimate of 44–55 Tmol yr−1 at 100 m for the ESMs to match the observed vertical gradient of alkalinity. Reviewing the representation of the CaCO3 cycle across CMIP5/6, we find a substantial range of parameterizations. While all biogeochemical models currently represent pelagic calcification, they do so implicitly, and they do not represent benthic calcification. In addition, most models simulate marine calcite but not aragonite. In CMIP6, certain model groups have increased the complexity of simulated CaCO3 production, sinking, dissolution and sedimentation. However, this is insufficient to explain the overall improvement in the alkalinity representation, which is therefore likely a result of marine biogeochemistry model tuning or ad hoc parameterizations. Although modellers aim to balance the global alkalinity budget in ESMs in order to limit drift in ocean carbon uptake under pre-industrial conditions, varying assumptions related to the closure of the budget and/or the alkalinity initialization procedure have the potential to influence projections of future carbon uptake. For instance, in many models, carbonate production, dissolution and burial are independent of the seawater saturation state, and when considered, the range of sensitivities is substantial. As such, the future impact of ocean acidification on the carbonate pump, and in turn ocean carbon uptake, is potentially underestimated in current ESMs and is insufficiently constrained.

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Storti, F., und F. Balsamo. „Particle size distributions by laser diffraction – Part 1: Sensitivity of granular matter strength to analytical operating procedures“. Solid Earth Discussions 1, Nr. 1 (21.12.2009): 93–141. http://dx.doi.org/10.5194/sed-1-93-2009.

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Abstract. We tested laser diffraction particle size analysis in poorly coherent carbonate platform cataclastic breccias and unfaulted quartz-rich eolian sands, representing low- and high-strength granular materials, respectively. We used two different instruments with different sample dispersion and pumping systems and several wet and dry analytical procedures that included different pump speeds, measure precision tests with and without sample ultrasonication, and different dispersant liquids. Results of our work indicate that high strength material is not strongly affected by analytical operating procedures, whereas low strength material is very sensitive to the pump speed, ultrasonication intensity, and measurement run time. To reduce such a data variability, we propose a workflow for analytical tests preliminary to the set up of the most appropriate SOP.

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Storti, F., und F. Balsamo. „Particle size distributions by laser diffraction: sensitivity of granular matter strength to analytical operating procedures“. Solid Earth 1, Nr. 1 (19.04.2010): 25–48. http://dx.doi.org/10.5194/se-1-25-2010.

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Abstract. We tested laser diffraction particle size analysis in poorly coherent carbonate platform cataclastic breccias and unfaulted quartz-rich eolian sands, representing low- and high-strength granular materials, respectively. We used two different instruments with different sample dispersion and pumping systems and several wet analytical procedures that included different pump speeds, measurement precision tests with and without sample ultrasonication, and different dispersant liquids. Results of our work indicate that high strength material is not strongly affected by analytical operating procedures, whereas low strength materials are very sensitive to the pump speed, ultrasonication intensity, and measurement run time. To reduce such a data variability, we propose a workflow of analytical tests preliminary to the set up of the most appropriate SOP.

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Salter, Ian, Ralf Schiebel, Patrizia Ziveri, Aurore Movellan, Richard Lampitt und George A. Wolff. „Carbonate counter pump stimulated by natural iron fertilization in the Polar Frontal Zone“. Nature Geoscience 7, Nr. 12 (10.11.2014): 885–89. http://dx.doi.org/10.1038/ngeo2285.

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Pautova, L. A., V. A. Silkin, M. D. Kravchishina, A. L. Chultsova und A. P. Lisitzin. „The Biological Calcium Carbonate Pump in the Norwegian and Barents Seas: Regulation Mechanisms“. Doklady Earth Sciences 490, Nr. 1 (Januar 2020): 46–50. http://dx.doi.org/10.1134/s1028334x20010079.

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Aheicheva, Oleksandra. „ANALYSIS OF MODEL RESULTS OF LABORATORY TESTS OF NEW ACID COMPONENTS FOR CARBONATE COLLECTOR“. Bulletin of the National Technical University "KhPI". Series: Innovation researches in students’ scientific work, Nr. 2 (22.12.2023): 28–35. http://dx.doi.org/10.20998/2220-4784.2023.02.04.

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Results of laboratory tests of new acid components for carbonate collector are considered in the article. Modeling acid treatment is described in the article. It is proved that the use of different methods simplifies this task, as it gives the correct results quickly and easily. The importance of the choice of well operation methods is analyzed. It has been proven that effectiveness of the developed acid malt should be used. The article examines the results of computer modeling of the process of pumping the acidic system into the productive reservoir. The change in the viscosity of the acid system in contact with the carbonate rock, obtained by modeling the process of exiting the emulsion from the pump-compressor pipes was studied. The results of this work are very important andnecessary for further research and well production analysis. Examples from the analysis of experimental research models of laboratory tests of new acid components for a carbonate collector can be applied in the training of students in the Chemical Engineering educational program.

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Jasem, Iman N., Hiba H. Abdullah und Mohammed Jalal Abdulrazzaq. „Dual-Wavelength Passively Q-Switched Erbium-Doped Fiber Laser Incorporating Calcium Carbonate Nanoparticles as Saturable Absorber“. Journal of Nanotechnology 2023 (28.09.2023): 1–11. http://dx.doi.org/10.1155/2023/8858582.

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This study experimentally demonstrates the operation of a dual-wavelength passively Q-switched erbium-doped fiber laser that incorporates CaCO3 nanoparticles as a saturable absorber (SA). The SA was prepared by using the drop-casting method, wherein CaCO3 nanoparticles were embedded in a polyvinyl alcohol (PVA) polymer to form a CaCO3/PVA film SA. The film was integrated into a ring laser cavity with a 976 nm pump to generate Q-switched pulses. The properties of the SA were examined experimentally, and its modulation depth is approximately 47%. As the pump power increased from 180 mW to 270 mW and the pulse repetition rate increased from 12.67 kHz to 21.3 kHz, the corresponding pulse width decreased from 35.27 μs to 18.74 μs. The signal-to-noise ratio was approximately 25 dB, highlighting the laser’s stability. The results indicate that the proposed CaCO3/PVA SA is suitable for realizing portable Q-switched lasers.

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Firdaus, Mochamad Ramdhan, und Lady Ayu Sri Wijayanti. „FITOPLANKTON DAN SIKLUS KARBON GLOBAL“. OSEANA 44, Nr. 2 (21.12.2019): 35–48. http://dx.doi.org/10.14203/oseana.2019.vol.44no.2.39.

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PHYTOPLANKTON AND GLOBAL CARBON CYCLE. Scientists around the world believe that phytoplankton, although microscopic, have a large role in the global carbon cycle. Various research results show that the net primary productivity of all phytoplankton in the sea is almost as large as the net primary productivity of all plants on land. Phytoplankton through the process of photosynthesis absorbs 40-50 PgC / year from the atmosphere. Also, phytoplankton is known to be responsible for transporting carbon from the atmosphere to the seafloor through the carbon biological pump mechanism. Phytoplankton from the coccolithophores group is known to play a role in the sequestration of carbon on the seabed through the carbonate pump mechanism. The mechanism is capable of sequestering carbon for thousands of years on the seabed in the form of sedimentary rocks (limestone).

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Patel, Vineetkumar, Arpan Chudasama, Manish Nivsarkar, Kamala Vasu und Chamanlal Shishoo. „Push-pull osmotic pump for zero order delivery of lithium carbonate: Development andin vitrocharacterization“. Pharmaceutical Development and Technology 17, Nr. 3 (02.02.2011): 375–82. http://dx.doi.org/10.3109/10837450.2010.542577.

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Sari, Vonny Indah. „PERBANDINGAN PENGGUNAAN KALSIUM KARBONAT DAN NATRIUM KARBONAT DALAM PEMISAHAN CANGKANG DAN KERNEL“. JURNAL TEKNOLOGI PERTANIAN 2, Nr. 1 (20.05.2013): 29–34. http://dx.doi.org/10.32520/jtp.v2i1.48.

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Clay bath is where the separation of the shell, core nucleus intact and broken. The process of separation occurs because of differences in density between the core with the shell with the help of a solution of CaCO3. Core with a lighter density in the solution of CaCO3 floats and shells with a greater specific gravity settle to the bottom. This process is carried out in a cone-shaped vessel is equipped with a pump to circulate CaCO3. The existence of the circulation of fluid motion will bring the kernel into the sieve vibration to be cleaned and then sent to the kernel in the Kernel Wet Fan heading to Kernel Shiloh to the heat. This reseach compared the performance of the solution with a solution of Na2CO3 and CaCO3 in their shells and kernels, seen from the solubility rate between kalsim carbonate and sodium carbonate in water

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Yahya, M. Farid, M. Faiz Malek und Reduan Mat Dan. „INVESTIGATION INTO MAGNETIC DRIVE SEALLESS PUMP FAILURE 3 FLARE GAS RECOVERY UNIT (FGRU)“. Platform : A Journal of Engineering 7, Nr. 1 (31.03.2023): 30. http://dx.doi.org/10.61762/pajevol7iss1art21997.

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Failure investigation was conducted on magnetic drive centrifugal sealless pumps that had only been operating for six months and were already struggling to rotate. It was discovered that hydrocarbon sludge and other debris had blocked the lubricating channel, which is meant to provide pathways for cooling and lubricating the pump's inner magnetic and containment shell. Further investigation revealed that service water had contaminated the process fluid, precipitating calcium carbonate upon contact with the amine solution and clogging the flushing line. An additional duplex strainer was installed on the repaired pumps, and adequate precautions were taken to prevent water contamination.Keywords: cleanliness, internal flushing, contamination, clogging, duplex strainer

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Yu, Tian Lan, Tian Xiang Yu, De Qi Peng, Li Chen, Xiu Yan Feng, Zhi Kun Zhang und Xiu Min Yu. „Research on Energy-Saving Technology for Salt Solution Heat Pump Evaporators“. Applied Mechanics and Materials 331 (Juli 2013): 216–21. http://dx.doi.org/10.4028/www.scientific.net/amm.331.216.

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Aiming at increasing the energy-saving efficiency of salt solution evaporation, the effect of several factors on heat pump energy-saving efficiency is studied through theoretical analyses and calculation. The factors include boiling point elevation caused by solution static pressure, superheat loss of surface evaporation, temperature difference loss caused by fouling. The conclusions are that falling-film evaporator helps improve heat pump evaporation energy-saving the most and forms the fluctuating flow of the falling film which can be used to remove fouling automatically. The Φ38mm×2mm single-tube dynamics experiment results show that the flow can produce stable 3D vibration of the cleaning spiral when the nominal flow velocity is more than 0.25m/s. The axial reciprocating motion distance is longer than one spiral pitch and reciprocating periodicity is 3-6 seconds. The sodium carbonate solution fouling removal experiment results show that the salt fouling decreases the overall heat transfer coefficient by 30% in one hour when there is no the 3D vibrating spiral-insert; and the insert can enhance heat transfer by 59% comparing to that during stable operation without this technology. Key Words: Falling-film Evaporator, Heat Pump Evaporate, Energy saving, Automatic cleaning, Heat transfer

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Jones, Elizabeth M., Mario Hoppema, Karel Bakker und Hein J. W. de Baar. „Calcium carbonate saturation states along the West Antarctic Peninsula“. Antarctic Science 33, Nr. 6 (28.10.2021): 575–95. http://dx.doi.org/10.1017/s0954102021000456.

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AbstractThe waters along the West Antarctic Peninsula (WAP) have experienced warming and increased freshwater inputs from melting sea ice and glaciers in recent decades. Challenges exist in understanding the consequences of these changes on the inorganic carbon system in this ecologically important and highly productive ecosystem. Distributions of dissolved inorganic carbon (CT), total alkalinity (AT) and nutrients revealed key physical, biological and biogeochemical controls of the calcium carbonate saturation state (Ωaragonite) in different water masses across the WAP shelf during the summer. Biological production in spring and summer dominated changes in surface water Ωaragonite (ΔΩaragonite up to +1.39; ~90%) relative to underlying Winter Water. Sea-ice and glacial meltwater constituted a minor source of AT that increased surface water Ωaragonite (ΔΩaragonite up to +0.07; ~13%). Remineralization of organic matter and an influx of carbon-rich brines led to cross-shelf decreases in Ωaragonite in Winter Water and Circumpolar Deep Water. A strong biological carbon pump over the shelf created Ωaragonite oversaturation in surface waters and suppression of Ωaragonite in subsurface waters. Undersaturation of aragonite occurred at < ~1000 m. Ongoing changes along the WAP will impact the biologically driven and meltwater-driven processes that influence the vulnerability of shelf waters to calcium carbonate undersaturation in the future.

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Aboelyazeed, Hossam, Sahar El-haggar und Kamal Okasha. „COMPARATIVE STUDY BETWEEN THE EFFECT OF HISTAMINE RECEPTOR ANTAGONISTS OF TYPE II (FAMOTIDINE) AND PROTON PUMP INHIBITORS (OMEPRAZOLE) ON THE EFFICACY OF CALCIUM CARBONATE AS PHOSPHATE BINDER IN HAEMODIALYSIS PATIENT“. International Journal of Pharmacy and Pharmaceutical Sciences 9, Nr. 8 (01.08.2017): 10. http://dx.doi.org/10.22159/ijpps.2017v9i8.12072.

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Objective: The purpose of this study was to compare the effect of famotidine versus omeprazole on the efficacy of calcium carbonate as a phosphate binder in the hemodialysis patient.Methods: From February 2014 to June 2014 a total number of 64 patients of both sexes were recruited from the department of renal dialysis, Tanta University Hospital, Egypt. Patients categorized into 3 groups. Group I (control group) consisted of 20 Patients (10) females and (10) males take calcium carbonate (caco3) (2.5–4 g/d) only, Group II consisted of 21 Patients (13) females and (8) males take the same dose of caco3 with famotidine 10 mg/d and Group III consisted of 23 Patients (8) females and (15) male take the same dose caco3 with omeprazole 20 mg/d.Results: All data are expressed as the mean±SD. Group II showed a significant increase (p<0.05) in serum phosphorus at 3rd mo with significant decreased (p<0.05) in serum calcium comparing with pre-treatment. Group III showed no significant change (p>0.05) in serum calcium, phosphorus and parathyroid hormone (PTH) comparing with pre-treatment. Both groups (II and III) showed a significant decrease in alkaline phosphatase (ALP) (p<0.05).Conclusion: Co-administration of famotidine with calcium carbonate aggravates hyperphosphatemia and this may increase the incidence of complications. The efficacy of calcium carbonate as a phosphate binder was not affected by co-administration of omeprazole.

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O’Connell, Mary Beth, Denyse M. Madden, Anne M. Murray, Robert P. Heaney und Lawrence J. Kerzner. „Effects of proton pump inhibitors on calcium carbonate absorption in women: A randomized crossover trial“. American Journal of Medicine 118, Nr. 7 (Juli 2005): 778–81. http://dx.doi.org/10.1016/j.amjmed.2005.02.007.

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Duarte Venturini, Carina, Paula Engroff, Vanessa Sgnaolin, Raquel Milani El Kik, Fernanda Bueno Morrone und Irenio Gomes. „Inadequação da ingestão alimentar em idosos: interação fármaco-nutriente“. PAJAR - Pan American Journal of Aging Research 8, Nr. 1 (30.03.2020): 34072. http://dx.doi.org/10.15448/2357-9641.2020.1.34072.

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Aims: to evaluate the inadequacy of food consumption and the estimated nutrient depletion caused by the use of drugs in the elderly.Methods: a cross-sectional population study, attended by 427 elderly. Food consumption was obtained from the 24-hour Food Recall Survey and the Research Dietetic History. The use of drugs was assessed by a pharmacotherapeutic questionnaire.Results: 85.8% of elderly use medications, the most prevalent inhibitors angiotensin converting enzyme inhibitor (29.2%), acetylsalicylic acid (28.7%), hydrochlorothiazide (24.4%), hydroxymethyl-glutaryl coenzyme A reductase enzyme inhibitor (17.0%), calcium carbonate (12.6%) and proton pump inhibitors (8.2%). Acetylsalicylic acid, hydrochlorothiazide and proton pump inhibitors are the drugs that possibly deplete the greatest number of nutrients. Users of hydroxymethyl-glutaryl coenzyme A reductase enzyme inhibitor, 97% could had inadequate for vitamin E; of potassium-sparing diuretics, 90.0% of inadequacy for magnesium; digoxin, 83.3% of inadequate for magnesium and 58.3% for calcium and potassium.Conclusions: the drugs most commonly used by elderly are responsible for the depletion of numerous micronutrients, often associated with a high prevalence of inadequate consumption, which may cause possible nutritional deficiencies.

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Widyanata, Andri. „ACIDIZING EVALUATION OF CARBONATE ROCK IN BDA-F WELL, JATIBARANG FIELD“. Journal of Petroleum and Geothermal Technology 4, Nr. 1 (17.05.2023): 12. http://dx.doi.org/10.31315/jpgt.v4i1.7335.

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Acidizing is a dissolving activity, whether it is dissolving rock formations or other materials (natural or foreign) in reservoir of the rock. To maintain production in the Jatibarang field, especially in Bangodua (BDA) structure, there are 1 well that have experienced a short decline in production since drilling. The reservoir properties of that well is not good and there is impurity material (damage). Thus, requiring stimulation in the form of matrix acidizing. Evaluation of the matrix acid work in this well, is required for the same activities in other wells.To restore productivity this well, data were collected starting from production data, reservoir data, and well composition data. Then, candidate analysis and matrix acidizing job design are carried out. The design stage will be brought to the execution of matrix acidizing in the field. Then an evaluation was carried out after the presence of matrix acidizing in this wellThis well carried out matrix acidizing activities, produced oil production gains. BDA-F well produced with artificial lift of Electrical submersible pump – ESP in C1 layer (1128 – 1130.5 mMD), experienced an increase in test production from 749 BLPD to 1865 BLPD with a decrease in skin factor from +32 to -1.

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Shangguan, Qipei, Huilin Shu, Peicong Li, Kunning Lin, Robert H. Byrne, Quanlong Li, Dongxing Yuan und Jian Ma. „Automated spectrophotometric determination of carbonate ion concentration in seawater using a portable syringe pump based analyzer“. Marine Chemistry 209 (Februar 2019): 120–27. http://dx.doi.org/10.1016/j.marchem.2019.01.007.

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Mahdi, Faiz, Timothy Hunter und Richard Holdich. „A Study of Cake Filtration Parameters Using the Constant Rate Process“. Processes 7, Nr. 10 (15.10.2019): 746. http://dx.doi.org/10.3390/pr7100746.

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The minerals calcium carbonate and talc were filtered under various conditions of filtrate flow rate and suspension concentration, using constant rate conditions with the aid of a peristaltic pump to draw the filtrate. Cake concentrations of between 0.41 and 0.53 v/v for calcium carbonate and 0.19 and 0.26 v/v for talc were recorded. The mean sizes of the two different minerals were very similar, but the average specific resistances obtained from the experiments were 5.9 × 1010 and 7.4 × 1011 m/kg for calcium carbonate and talc, respectively. These results do not agree with what would be predicted from an analytical equation for permeability, such as Kozeny-Carman. In addition, discontinuities were observed in all cases on the curves of filtrate volume with time for the initial stage of filtration. This behaviour is attributed to retarded packing compressibility (RPC) complicating the analysis of the filter medium resistance. RPC is an important component in determining the filter cake resistance and its functionality with cake forming pressure. It is found that there are additional effects that enhance the resistance to permeation in different cake materials, which is not recognised in the standard analytical approaches. These complexities can be related to shape, polydispersity, or agglomeration within the material sample and not to the experimental equipment or procedure. Furthermore, a complete and straightforward methodology is presented in this work for investigating the significance, or otherwise, of medium resistance on the later stages of the filtration.

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Báez-Hernández, Maite, Noemí García, Inmaculada Menéndez, Alfredo Jaramillo, Isora Sánchez-Pérez, Ángelo Santana, Ignacio Alonso, José Mangas und Santiago Hernández-León. „Interaction of sinking behaviour of Saharan dust and lithogenic and biogenic fluxes in the Canary Basin“. Scientia Marina 83, Nr. 2 (18.06.2019): 121. http://dx.doi.org/10.3989/scimar.04877.19a.

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Saharan dust events are currently the predominant source of lithogenic particles in the Canary Basin. In order to quantify this input and its relationship with the biogenic fluxes, a sediment trap was deployed in a free-drifting system at 150 m depth, 50 km off the north coast of Gran Canaria (Canary Islands). The mineralogy of the lithogenic particles included illite, calcite, hematite quartz, barite and kaolinite. The biogenic matter was composed of chitin, transparent exopolymer particles, and carbonates from foraminifera and gastropod shells. The average Saharan dust flux over the ocean surface was approximately 5±4 mg m–2 day-1. The lithogenic, carbonate and chitin fluxes were 0.8±0.6, 6.0±7.4 and 154±386 mg m–2 day-1, respectively. A fairly strong Saharan dust event during sampling was observed in the trap, with a delay of three days in the peaks of lithogenic and biogenic fluxes. The theoretical settling velocity of the lithogenic particles associated with Saharan dust events at 150 m depth was vStokes=275 m day-1, and the experimental settling was about 50 m day-1. The associated sinking behaviour of particulate organic carbon and biogenic and lithogenic fluxes observed in this study may contribute to a more realistic prediction of these fluxes in carbon biological pump models.

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Cavaleiro, Catarina, Antje H. L. Voelker, Heather Stoll, Karl-Heinz Baumann und Michal Kucera. „Coccolithophore productivity at the western Iberian Margin during the Middle Pleistocene (310–455 ka) – evidence from coccolith Sr∕Ca data“. Climate of the Past 16, Nr. 6 (03.11.2020): 2017–37. http://dx.doi.org/10.5194/cp-16-2017-2020.

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Abstract. Coccolithophores contribute significantly to marine primary productivity and play a unique role in ocean biogeochemistry by using carbon for photosynthesis (soft-tissue pump) and for calcification (carbonate counter pump). Despite the importance of including coccolithophores in Earth system models to allow better predictions of the climate system's responses to planetary change, the reconstruction of coccolithophore productivity mostly relied on proxies dependent on accumulation and sedimentation rates and preservation conditions. In this study we used an independent proxy, based on the coccolith fraction (CF) Sr∕Ca ratio, to reconstruct coccolithophore productivity. We studied the marine sediment core MD03-2699 from the western Iberian margin (IbM), concentrating on glacial–interglacial cycles of Marine Isotopic Stage (MIS) 12 to MIS 9. We found that IbM coccolithophore productivity was controlled by changes in the oceanographic conditions, such as in sea surface temperature (SST) and nutrient availability, and by competition with other phytoplankton groups. Long-term coccolithophore productivity was primarily affected by variations in the dominant surface water mass. Polar and subpolar surface waters during glacial substages were associated with decreased coccolithophore productivity, with the strongest productivity minima concomitant with Heinrich-type events (HtEs). Subtropical, nutrient-poorer waters, increased terrigenous input, and moderate to strong upwelling during the deglaciation and early MIS11 are hypothesized to have attributed a competitive advantage to diatoms to the detriment of coccolithophores, resulting in intermediate coccolithophore productivity levels. During the progression towards full glacial conditions an increasing presence of nutrient-richer waters, related to the growing influence of transitional surface waters and/or intensified upwelling, probably stimulated coccolithophore productivity to maxima following the rapid depletion of silica by diatoms. We present conceptual models of the carbon and carbonate cycle components for the IbM in different time slices that might serve as a basis for further investigation and modelling experiments.

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Choi, Hanna, Jaeyeon Kim, Byoung Ohan Shim und Dong-hun Kim. „Characterization of Aquifer Hydrochemistry from the Operation of a Shallow Geothermal System“. Water 12, Nr. 5 (13.05.2020): 1377. http://dx.doi.org/10.3390/w12051377.

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The use of shallow geothermal energy systems utilizing groundwater temperature for the air-conditioning of buildings is increasing worldwide. The impact of these systems on groundwater quality has become crucial for environmental regulations and system design. For the long-term operation of geothermal systems, it is important to evaluate their influence on the geochemical properties of groundwater, including precipitation and dissolution of secondary minerals. This research was conducted in a real-scale geothermal system, consisting of a groundwater heat pump (GWHP). Hydrochemical data were obtained from samples collected from an aquifer before heating, during heating, and before cooling operations of the GWHP. The Langelier Saturation Index and Ryznar Stability Index were calculated, and the saturation index was simulated with the PHREEQC program. Evidence from water table variation, temperature change, and 87 Sr/ 86 Sr isotope distribution showed that groundwater flows from a well located on the northwest side of the geothermal well. The saturation index values showed that the pristine groundwater favors carbonate dissolution, however, manganese oxides are more sensitive to temperature than carbonate minerals. In addition, mineral precipitation and dissolution were found to vary with depth and temperature.

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Ahmad, Mariani, Azrilawani Ahmad, Tuan Fauzan Tuan Omar, Hafiza Mohamed Zuki und Marinah Mohd Ariffin. „MODIFICATION OF PROTON PUMP MEMBRANE USING POLYVINYLPYRROLIDONE (PVP) FOR POTENTIAL TOTAL ALKALINITY SENSING“. Jurnal Teknologi 85, Nr. 2 (23.02.2023): 175–81. http://dx.doi.org/10.11113/jurnalteknologi.v85.19019.

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Total alkalinity is one of the important parameter in the regulation of seawater carbonate chemistry system to determine the capacity of water to neutralize acid. In this paper, a new proton pump membrane was successfully modified using polyvinylpyrrolidone (PVP) as a supporting material due to its excellent chemical properties. The surface morphology of the membrane was thoroughly studied using Scanning Electron Microscope (SEM), which showed the presence of pore structure, ascribed to the presence of low molecular weight of PVP. The absorption of membrane was studied using Ultraviolet-Visible (UV-Vis) spectrophotometer, where the peak appeared at 539 nm-1. The functional group of the modified membrane was analyzed using Fourier Transform Infrared Spectroscopy (FTIR), and the spectra showed almost similar between modified membrane with PVP and without PVP. The electrochemical behaviour of the membrane was evaluated by cyclic voltammetry (CV) using gold (Au) electrode and the resulting voltammogram showed that the modified membrane with PVP has higher current reading compared to the membrane without PVP, indicating that there is redox reaction occured during the immobilization. The condition and perfomance of modified proton pump membrane with PVP was compared and analyzed.

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Erlund, Rickard, und Ron Zevenhoven. „Simulations on Design and System Performance of Building Heating Boosted by Thermal Energy Storage (TES) with Magnesium Hydro Carbonates/Silica Gel“. Energies 13, Nr. 17 (01.09.2020): 4520. http://dx.doi.org/10.3390/en13174520.

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In this paper, a simulations model of a seasonal thermal energy storage (TES) reactor integrated into a house heating system is presented. The water vapour chemisorbing reactor contains a composite material composed of silica gel and hydrated magnesium carbonate (nesquehonite, MgCO3·3H2O) that can be produced by a carbon capture and storage by mineralisation process. The performance of the TES to supply winter heat instead of electrical resistance heat is analysed. Dividing the reactor into a few units (connected in series) for better heat output and storage capacity as developed by the authors is compared to one unit or parallel unit solutions. The heating system components are an exhaust air heat pump, solar collectors and a heat recovery ventilation unit (HRV). The TES is used as heat source during colder periods, which implies improved efficiency and coefficient of performance (COP). Around 70% of electrical resistance heat, assisting an exhaust air heat pump during cold periods, can be substituted with heat from the TES according to the simulation model. Connecting three units in series will increase the usable storage capacity possibilities with by a 49% higher heat output.

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Al-Ghamdi, Rasha A., und Husin Sitepu. „Characterization of Sludge Deposits from Refineries and Gas Plants: Prerequisite Results Requirements to Facilitate Chemical Cleaning of the Particular Equipment“. International Journal of Corrosion 2018 (02.09.2018): 1–8. http://dx.doi.org/10.1155/2018/4121506.

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In this paper, the method developed by the authors to separate the inorganic materials from the hydrocarbon of the sludge deposits, which is fast and can accurately identify very small quantities of inorganic materials, has been extended to characterize the 12 types of sludge samples collected from (a) a regeneration overhead acid gas condenser, (b) water draw-off pump’s suction strainer in a gas plant, and (c) condenser, inside vessels of inlet head, and head coiler tube equipment at gas plants. The results revealed that the major phases are (a) iron sulfide corrosion products with the hydrocarbon type of mixture of diesel and lube oil for a condenser and (b) carbonate scale in the form of calcium carbonate with the hydrocarbon type of lubricant oil for sludge deposits from a suction strainer for pumps, and drilling mud in the form of barium sulfate with no organic hydrocarbon or polymer for sludge samples from a water recycling pump. Moreover, the major phases for inorganic materials built up in a condenser, inside the vessel’s inlet head, and the head coiler tube revealed that iron oxide corrosion products are found in the steam drum, and iron sulfate corrosion products are built up in the condenser. The presence of dissolved oxygen in the boiler feed water is indicated by a high wt% of iron oxide corrosion product in the form of magnetite (Fe3O4), which appeared in the inorganic materials built up in the condenser steam drum. Knowing accurately which phases and their wt% were involved in the inorganic materials can guide the field engineers to facilitate efficient cleaning of the equipment by drawing up the right procedures and taking preventive action to stop the generation of those particular sludge deposits.

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Guerreiro, Catarina V., Karl‐Heinz Baumann, Geert‐Jan A. Brummer, André Valente, Gerhard Fischer, Patrizia Ziveri, Vanda Brotas und Jan‐Berend W. Stuut. „Carbonate fluxes by coccolithophore species between NW Africa and the Caribbean: Implications for the biological carbon pump“. Limnology and Oceanography 66, Nr. 8 (21.06.2021): 3190–208. http://dx.doi.org/10.1002/lno.11872.

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50

Ishihara, Akimitsu. „High Temperature Electrochemical Heat Pump Using Water Gas Shift Reaction-Electrolytic Reduction of CO2 in Molten Carbonate“. ECS Proceedings Volumes 1999-41, Nr. 1 (Januar 1999): 744–51. http://dx.doi.org/10.1149/199941.0744pv.

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