Journal articles on the topic 'Rewetting'
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1
Chan, S. H., J. D. Blake, T. R. Shen, and Y. G. Zhao. "Effects of Gravity on Rewetting of Capillary Groove Surface at Elevated Temperatures—Experimental and Theoretical Studies." Journal of Heat Transfer 117, no. 4 (November 1, 1995): 1042–47. http://dx.doi.org/10.1115/1.2836279.
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Theoretical and experimental investigations of the rewetting characteristics of thin liquid films over heated and unheated capillary grooved plates were performed. To investigate the effect of gravity on rewetting, the grooved surface was placed in upward and downward-facing positions. Profound gravitational effects were observed as the rewetting velocity was found to be higher in the upward than in the downward-facing orientation. The difference was even greater with higher initial plate temperatures. With either orientation, it was found that the rewetting velocity increased with the initial plate temperature. But when the temperature was raised above a rewetting temperature, the rewetting velocity decreased with the initial plate temperature. Hydrodynamically controlled and heat conduction controlled rewetting models were then presented to explain and to predict the rewetting characteristics in these two distinct regions. The predicted rewetting velocities were found to be in good agreement with experimental data with elevated plate temperatures.
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Zheng, Ying Ying, Xin Shan Song, and Xiao Xiang Zhao. "The Effect of Drying-Rewetting on Soil Nitrogen Nitrification." Advanced Materials Research 610-613 (December 2012): 385–89. http://dx.doi.org/10.4028/www.scientific.net/amr.610-613.385.
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More frequently drying-rewetting is likely to be expected for soils this century, with strong effect on nitrogen transformation. Experiments were conducted in semi-disturbed soils which were incubated under 4 different moisture regimes (dry wet\constant wet\constant dry\constant flooded) for 71 d. The results show that the dry soil has a rapid NO3--N increase after rewetting. Drying-rewetting increases soil nitrification which shows a "pulse" increasing. The drying and rewetting soil has the highest nitrification intensity when the soil moisture content (g/g) ranging at 15.82% ~ 17.06%. Drying-rewetting contributes to the accumulation of NO3--N.
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Peterson, G. P., and X. F. Peng. "Experimental Investigation of Capillary-Induced Rewetting in a Flat Porous Wicking Structure." Journal of Energy Resources Technology 115, no. 1 (March 1, 1993): 62–69. http://dx.doi.org/10.1115/1.2905971.
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An experimental program was conducted to investigate the rewetting characteristics of liquid flowing through multiple layers of screen mesh covering a heated vertical plate. Data obtained for acetone and R-11 were analyzed and compared with previously developed theoretical expressions for the rewetting velocity, the maximum liquid rise height, and the maximum heat flux for which rewetting could occur. The experimental results indicate that the thickness of the screen mesh layer and the liquid thermophysical properties are the most important factors affecting the rewetting behavior. As predicted by the theoretical model, small increases in the thickness of the screen layer initially caused the maximum permissible rewetting heat flux to increase. Once the layer thickness had reached a critical value, continued increases resulted in a decrease in the maximum permissible rewetting heat flux.
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Lestari, Iska, Daniel Murdiyarso, and Muh Taufik. "Rewetting Tropical Peatlands Reduced Net Greenhouse Gas Emissions in Riau Province, Indonesia." Forests 13, no. 4 (March 24, 2022): 505. http://dx.doi.org/10.3390/f13040505.
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Draining deforested tropical peat swamp forests (PSFs) converts greenhouse gas (GHG) sinks to sources and increases the likelihood of fire hazards. Rewetting deforested and drained PSFs before revegetation is expected to reverse this outcome. This study aims to quantify the GHG emissions of deforested PSFs that have been (a) reforested, (b) converted into oil palm, or (c) replanted with rubber. Before rewetting, heterotrophic soil respiration in reforested, oil palm, and rubber plantation areas were 48.91 ± 4.75 Mg CO2 ha−1 yr−1, 54.98 ± 1.53 Mg CO2 ha−1 yr−1, and 67.67 ± 2.13 Mg CO2 ha−1 yr−1, respectively. After rewetting, this decreased substantially by 21%, 36%, and 39%. Conversely, rewetting drained landscapes that used to be methane (CH4) sinks converted them into CH4 sources; almost twice as much methane was emitted after rewetting. Nitrous oxide (N2O) emissions tended to decrease; in nitrogen-rich rubber plantations, N2O emissions halved; in nitrogen-poor reforested areas, emissions reduced by up to a quarter after rewetting. Overall, rewetting reduced the net emissions up to 15.41 Mg CO2-eq ha−1 yr−1 (25%) in reforested, 18.36 Mg CO2-eq ha−1 yr−1 (18%) in oil palm, and 28.87 Mg CO2-eq ha−1 yr−1 (17%) in rubber plantation areas.
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Chan, S. H., and W. Zhang. "Rewetting Theory and the Dryout Heat Flux of Smooth and Grooved Plates With a Uniform Heating." Journal of Heat Transfer 116, no. 1 (February 1, 1994): 173–79. http://dx.doi.org/10.1115/1.2910852.
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The evaporation and condensation of thin liquid films are of significant importance in a wide variety of problems ranging from specific applications in the heat pipe field to more general ones in the chemical, nuclear, and petrochemical industries. Although several investigations have been conducted to determine the rewetting characteristics of liquid films on heated rods, tubes, and flat plates, no solutions are yet available to describe the rewetting process of a hot plate subjected to a uniform heating. A model is presented to analyze the rewetting process of such plates with and without grooves. Approximate analytical solutions are presented for the prediction of the rewetting velocity and the transient temperature profiles of the plates. It is shown that the present rewetting velocity solution reduces correctly to the existing solution for the rewetting of an initially hot isothermal plate without heating from beneath the plate. Numerical solutions have also been obtained to validate the analytical solutions. Finally, a simple method is presented to predict the dryout heat flux of a liquid film flowing over a heated smooth or grooved plate. The results of the prediction are found to be in reasonable agreement with the existing experimental data.
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Weislogel, M. M., and S. H. Collicott. "Capillary Rewetting of Vaned Containers: Spacecraft Tank Rewetting Following Thrust Resettling." AIAA Journal 42, no. 12 (December 2004): 2551–61. http://dx.doi.org/10.2514/1.3394.
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Leizeaga, Ainara, Annelein Meisner, Johannes Rousk, and Erland Bååth. "Repeated drying and rewetting cycles accelerate bacterial growth recovery after rewetting." Biology and Fertility of Soils 58, no. 4 (February 7, 2022): 365–74. http://dx.doi.org/10.1007/s00374-022-01623-2.
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AbstractTwo patterns of bacterial growth response upon drying and rewetting (DRW) of soils have previously been identified. Bacterial growth can either start increasing immediately after rewetting in a linear fashion (“type 1” response) or start increasing exponentially after a lag period (“type 2” response). The effect of repeated DRW cycles was studied in three soils with different response patterns after a single DRW cycle (“type 1”, “type 2” with a short lag period and “type 2” with a long lag period). The soils were exposed to seven DRW cycles, and respiration and bacterial growth were monitored after 1, 2, 3, 5, and 7 cycles. Exposure to repeated DRW shifted the bacterial growth response from a “type 2” to a “type 1” pattern, resulting in an accelerated growth recovery to a pre-disturbance growth rate. Bacterial growth in soils that initially had a “type 1” response also tended to recover faster after each subsequent DRW cycle. The respiration patterns after DRW also indicated the same transition from a “type 2” to a “type 1” pattern. Our results show that exposure to repeated DRW cycles will shape the bacterial response to future DRW cycles, which might be mediated by a shift in species composition, a physiological adjustment, evolutionary changes, or a combination of the three.
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Zhang, Yushuai, Baokun Xu, Jiangpei Han, and Liangsheng Shi. "Effects of Drying-Rewetting Cycles on Ferrous Iron-Involved Denitrification in Paddy Soils." Water 13, no. 22 (November 12, 2021): 3212. http://dx.doi.org/10.3390/w13223212.
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Soil moisture status has an important effect on the process of denitrification in paddy soils. However, it is unclear how it affects the ferrous iron-involved denitrification. Here, the influence of drying-rewetting cycles on ferrous iron-involved denitrification in paddy soil were studied with batch experiments. The dynamics of nitrate, ammonia, Fe2+, Fe3+ and total organic carbon (TOC), as well as nitrous oxide (N2O) were investigated using the iron-rich paddy soil in Jiangxi province, South China. Results demonstrated that the denitrification rate dropped while ammonia nitrogen content (NH4+-N) showed a rapid accumulation in the drying period. In the rewetting period, organic carbon played two-side roles. Organic carbon and ferrous iron together provided electron donors to denitrification, and organic carbon simultaneously reduced ferric iron under anaerobic environment. There were complex interactions among organic carbon, nitrate and Fe2+/Fe3+ under drying-rewetting cycles. Soil rewetting led to denitrification flush, especially after a moderately long drying period, while excessively frequent drying-rewetting alternation was not favorable to nitrate denitrification.
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Kumar, M., and D. Mukhopadhyay. "Heat transfer characterization under radial jet and falling film induced rewetting." Kerntechnik 86, no. 5 (October 1, 2021): 325–37. http://dx.doi.org/10.1515/kern-2021-0013.
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Abstract Empirical correlations are developed for rewetting velocity and maximum heat transfer coefficient during rewetting phase of single hot vertical Fuel Pin Simulator (FPS) by using radial jet impingement and falling film. Emergency Core Cooling System (ECCS) has been designed for Advance Heavy water Reactor (AHWR) to rewet the hot fuel pin under the loss of coolant accident. Coolant injection takes place from a water rod which is located at the center of the fuel bundle in form of jets to rewet hot surface of fuel pin under loss of coolant accident. This kind of design to reflood the fuel bundle is different than bottom and top spray reflooding practiced in PWR and BWR type of nuclear reactors. There are two different kinds of rewetting found during radial jet induced cooling. The first one is due to radial jet impingement and the second one is due to falling film which is below the jet impingement point. Rewetting velocity has been predicted along the length of fuel pin due to radial jet impingement cooling. Temperature of FPS has been varied from 400°C to 700°C with help of different powers supply, simulating decay heat of reactor. A variation of coolant radial jet mass flow rate is from 0.5 lpm to 1.8 lpm. It is considered during ECCS injection. It has been observed from the experiments that rewetting velocity decreases with increasing the clad surface temperature and increases with increasing the coolant mass flow rate. The rewetting velocity in falling film is found to be nearly 1.8 times higher than rewetting velocity predicted in circumferential direction. Further, it is found that maximum heat transfer coefficient increases with increasing the radial jet coolant mass flow rate. The maximum heat transfer coefficient in case of radial jet impingement is found to be nearly 1.5 times the falling film rewetting. Developed correlation predicts the maximum heat transfer coefficient with experimental data well within the error band of ±10%.
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Ouenzerfi, Safouene, Souad Harmand, and Jesse Schiffler. "Leidenfrost Self-Rewetting Drops." Journal of Physical Chemistry B 122, no. 18 (April 19, 2018): 4922–30. http://dx.doi.org/10.1021/acs.jpcb.7b11944.
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Negassa, Wakene, Dirk Michalik, Wantana Klysubun, and Peter Leinweber. "Phosphorus Speciation in Long-Term Drained and Rewetted Peatlands of Northern Germany." Soil Systems 4, no. 1 (February 10, 2020): 11. http://dx.doi.org/10.3390/soilsystems4010011.
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Previous studies, conducted at the inception of rewetting degraded peatlands, reported that rewetting increased phosphorus (P) mobilization but long-term effects of rewetting on the soil P status are unknown. The objectives of this study were to (i) characterize P in the surface and subsurface horizons of long-term drained and rewetted percolation mires, forest, and coastal peatlands and (ii) examine the influence of drainage and rewetting on P speciation and distributions using wet-chemical and advanced spectroscopic analyses. The total P was significantly (p < 0.05) different at the surface horizons. The total concentration of P ranged from 1022 to 2320 mg kg−1 in the surface horizons and decreased by a factor of two to five to the deepest horizons. Results of the chemical, solution 31P nuclear magnetic resonance (NMR), and P K-edge X-ray absorption near-edge structure (XANES) indicated that the major proportions of total P were organic P (Po). In the same peatland types, the relative proportions of Po and stable P fractions were lower in the drained than in the rewetted peatland. The results indicate that long-term rewetting not only locks P in organic matter but also transforms labile P to stable P fractions at the surface horizons of the different peatland types.
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Wang, Yuan, Yingying Zheng, Xin Shan Song, and Deng Hua Yan. "Drying-Rewetting Effects on Soil Nitrogen and Enzyme Activities Dynamics." Applied Mechanics and Materials 409-410 (September 2013): 256–61. http://dx.doi.org/10.4028/www.scientific.net/amm.409-410.256.
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With climate changes, soil may experience frequent drying-rewetting events. Water stress influences soil nitrogen transformation by affecting microbial growth and enzyme activities. The objective of this study was to determine effects of drying-rewetting cycles on soil N transformations and enzyme activities involved. The results show high correlations between soil inorganic N (NH4+-N & NO3--N) concentrations and soil moisture. Drying and rewetting events contributed to the accumulation of NO3--N. There was a significant correlation between NH4+-N/TDN and urease activities with a correlation coefficient of 0.88. Denitrifying enzyme activity showed a high positive correlation with soil moisture.
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Kim, D. G., R. Vargas, B. Bond-Lamberty, and M. R. Turetsky. "Effects of soil rewetting and thawing on soil gas fluxes: a review of current literature and suggestions for future research." Biogeosciences 9, no. 7 (July 9, 2012): 2459–83. http://dx.doi.org/10.5194/bg-9-2459-2012.
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Abstract. The rewetting of dry soils and the thawing of frozen soils are short-term, transitional phenomena in terms of hydrology and the thermodynamics of soil systems. The impact of these short-term phenomena on larger scale ecosystem fluxes is increasingly recognized, and a growing number of studies show that these events affect fluxes of soil gases such as carbon dioxide (CO2), methane (CH4), nitrous oxide (N2O), ammonia (NH3) and nitric oxide (NO). Global climate models predict that future climatic change is likely to alter the frequency and intensity of drying-rewetting events and thawing of frozen soils. These future scenarios highlight the importance of understanding how rewetting and thawing will influence dynamics of these soil gases. This study summarizes findings using a new database containing 338 studies conducted from 1956 to 2011, and highlights open research questions. The database revealed conflicting results following rewetting and thawing in various terrestrial ecosystems and among soil gases, ranging from large increases in fluxes to non-significant changes. Studies reporting lower gas fluxes before rewetting tended to find higher post-rewetting fluxes for CO2, N2O and NO; in addition, increases in N2O flux following thawing were greater in warmer climate regions. We discuss possible mechanisms and controls that regulate flux responses, and recommend that a high temporal resolution of flux measurements is critical to capture rapid changes in gas fluxes after these soil perturbations. Finally, we propose that future studies should investigate the interactions between biological (i.e., microbial community and gas production) and physical (i.e., porosity, diffusivity, dissolution) changes in soil gas fluxes, apply techniques to capture rapid changes (i.e., automated measurements), and explore synergistic experimental and modelling approaches.
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Senthilkumar, Rathinasamy, Subaiah Vaidyanathan, and Sivaramanb Balasubramanian. "Thermal analysis of heat pipe using self rewetting fluids." Thermal Science 15, no. 3 (2011): 879–88. http://dx.doi.org/10.2298/tsci101102020s.
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This paper discuses the use of self rewetting fluids in the heat pipe. In conventional heat pipes, the working fluid used has a negative surface-tension gradient with temperature. It is an unfavourable one and it decreases the heat transport between the evaporator section and the condenser section. Self rewetting fluids are dilute aqueous alcoholic solutions which have the number of carbon atoms more than four. Unlike other common liquids, self-rewetting fluids have the property that the surface tension increases with temperature up to a certain limit. The experiments are conducted to improve the heat-transport capability and thermal efficiency of capillary assisted heat pipes with the self rewetting fluids like aqueous solutions of n-Butanol and n-Pentanol and its performance is compared with that of pure water. The n-Butanol and n-Pentanol are added to the pure water at a concentration of 0.001moles/lit to prepare the self rewetting fluids. The heat pipes are made up of copper container with a two-layered stainless steel wick consisting of mesh wrapped screen. The experimental results show that the maximum heat transport of the heat pipe is enhanced and the thermal resistances are considerably decreased than the traditional heat pipes filled with water. The fluids used exhibit an anomalous increase in the surface tension with increasing temperature.
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Allegrini, Marco, Elena Gomez, and María Celina Zabaloy. "Acute glyphosate exposure does not condition the response of microbial communities to a dry–rewetting disturbance in a soil with a long history of glyphosate-based herbicides." SOIL 6, no. 2 (July 15, 2020): 291–97. http://dx.doi.org/10.5194/soil-6-291-2020.
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Abstract. Dry–rewetting perturbations are natural disturbances in the edaphic environment and particularly in dryland cultivation areas. The interaction of this disturbance with glyphosate-based herbicides (GBHs) deserves special attention in the soil environment due to the intensification of agricultural practices and the acceleration of climate change with an intensified water cycle. The objective of this study was to assess the response of microbial communities in a soil with a long history of GBHs to a secondary imposed perturbation (a single dry–rewetting event). A factorial microcosm study was conducted to evaluate the potential conditioning effect of an acute glyphosate exposure on the response to a following dry–rewetting event. A respiratory quotient (RQ) based on an ecologically relevant substrate (p-coumaric acid) and basal respiration was used as a physiological indicator. Similarly, DNA-based analyses were considered, including quantitative PCR (qPCR) of functional sensitive microbial groups linked to cycles of carbon (Actinobacteria) and nitrogen (ammonia-oxidizing microorganisms), qPCR of total bacteria and denaturing gradient gel electrophoresis (DGGE) of ammonia-oxidizing bacteria (AOB). Significant effects of herbicide and of dry–rewetting perturbations were observed in the RQ and in the copy number of the amoA gene of AOB, respectively. However, no significant interaction was observed between them when analyzing the physiological indicator and the copy number of the evaluated genes. PCR–DGGE results were not conclusive regarding a potential effect of dry–rewetting × herbicide interaction on AOB community structure, suggesting further analysis by deep sequencing of the amoA gene. The results of this study indicate that the perturbation of an acute glyphosate exposure in a soil with a long history of this herbicide does not have a conditioning effect on the response to a subsequent dry–rewetting disturbance according to a physiological indicator or the quantified bacterial/archaeal genes. This is particularly relevant for the sustainability of soils in rainfed agriculture, where frequent exposure to GBHs along with intensification of hydrological cycles are expected to occur. Further studies considering multiple dry–rewetting disturbances and in different soil types should be conducted to simulate those conditions and to validate our results.
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Dianti, Afiri, Nadhira Gilang Ratnasari, Pither Palamba, and Yulianto Nugroho. "Effect of Rewetting on Smouldering Combustion of a Tropical Peat." E3S Web of Conferences 67 (2018): 02042. http://dx.doi.org/10.1051/e3sconf/20186702042.
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Probability of land and forest fire in Indonesia is quite high. Peat land is one of the highest contribute of the fire disaster. Indonesia is the country with the highest peat land in Southeast Asia, with more than 50 % of tropical peat species. Combustion of peat produced carbon emission with large quantities and affect to global warming. Characteristic of smoldering combustion of peat cause detection and extinction be difficult. Moreover, there are another impact such as high erosion potential, structural collapse and soil layer damage. Flameless on peat smoldering causes peat restoration institution build fire prevention method. Regulation of water table on peat land with rewetting method aims to maintain and restore the moisture of peat. The experiment aims to understand characteristic of smoldering combustion of rewetting peat. Sample used in the experiments was taken from Bagaiserwar village, Sarmi, Papua (01°55’14, 11”, E: 138°6’17, 35”). A set of thermocouples were used to explore horizontal spread rate at 80 mm intervals. Mass loss rate indicates derivation caused by evaporation on wet peat. Author discovered a fire risk is higher than natural combustion in experiments with rewetting peat. Spread rate of smoldering is high on rewetting peat with initial MC before rewetting is ≤ 10 %. Hydrophobic of peat cause retention of water on peat changes. This phenomenon causes evaporation process being faster and total combustion time occur rapidly, start from preheating until self extinction.
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Sahu, Santosh, Prasanta Das, and Souvik Bhattacharyya. "Analytical and semi-analytical models of conduction controlled rewetting: A state of the art review." Thermal Science 19, no. 5 (2015): 1479–96. http://dx.doi.org/10.2298/tsci121231125s.
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The phenomenon of rewetting finds application in several fields of industrial and scientific applications including the loss of coolant accidents (LOCA) in nuclear reactors. In order to analyze the phenomena of rewetting, usually a conduction controlled approach or hydrodynamic approach was considered. Because of complexity, most of the studies adopt a conduction controlled approach to analyze the phenomena of rewetting. In view of this, various analytical and semi-analytical techniques have been used to solve the conduction equation. Investigations have mostly considered different geometries, various convective boundary conditions for both the dry and wet surface, effect of heat generation, variable properties, coupling between conduction and convection as well as other variations of the problem. A comprehensive review of the available analytical modelsis presented in this paper.
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Abdul-Razzak, A., M. Shoukri, and A. M. C. Chan. "Rewetting of hot horizontal tubes." Nuclear Engineering and Design 138, no. 3 (December 1992): 375–88. http://dx.doi.org/10.1016/0029-5493(92)90072-4.
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Mrotzek, Almut, Dierk Michaelis, Anke Günther, Nicole Wrage-Mönnig, and John Couwenberg. "Mass Balances of a Drained and a Rewetted Peatland: on Former Losses and Recent Gains." Soil Systems 4, no. 1 (March 16, 2020): 16. http://dx.doi.org/10.3390/soilsystems4010016.
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Drained peatlands are important sources of greenhouse gases and are rewetted to curb these emissions. We study one drained and one rewetted fen in terms of losses—and, after rewetting—gains of organic matter (OM), carbon (C), and peat thickness. We determined bulk density (BD) and ash/OM (and C/OM) ratios for 0.5 cm thick contiguous slices from peat monoliths to calculate losses. Whereas one site has lost 28.5 kg OM m−2 corresponding to annual emissions of ~10 t CO2 ha−1 a−1 over 50 years of effective drainage, the other site has lost 102 kg OM m−2, corresponding to an annual loss of ~30 t CO2 ha−1 a−1 for 30 years of intensive drainage and 6 t CO2 ha−1 a−1 during ~225 years of weak drainage before that. Height losses ranged from 43 to 162 cm. In the 20 years after rewetting, 2.12 kg C m−2 was accumulated, equaling an average annual uptake of ~0.4 kg CO2 m−2 a−1. The results indicate that rewetting can lead to carbon accumulation in fens. This sink function is only small compared with the high emissions that are avoided through rewetting.
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Knorr, K. H., B. Glaser, and C. Blodau. "Fluxes and <sup>13</sup>C isotopic composition of dissolved carbon and pathways of methanogenesis in a fen soil exposed to experimental drought." Biogeosciences Discussions 5, no. 2 (April 2, 2008): 1319–60. http://dx.doi.org/10.5194/bgd-5-1319-2008.
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Abstract. The impact of drought and rewetting on carbon cycling in peatland ecosystems is currently debated. We studied the impact of experimental drought and rewetting on intact monoliths from a temperate fen over a period of ~300 days, using a permanently wet treatment and two treatments undergoing drought for 50 days. In one of the mesocosms vegetation had been removed. Net production of CH4 was calculated from mass balances in the peat and emission using static chamber measurements and results compared to 13C isotope budgets of CO2 and CH4 and energy yields of acetoclastic and hydrogenotrophic methanogenesis. Drought retarded methane production after rewetting for days to weeks and promoted methanotrophic activity. Based on isotope and flux budgets, aerobic soil respiration contributed 32–96% in the wet and 86–99% in the other treatments. Drying and rewetting did not shift methanogenic pathways according to δ 13C ratios of CH4 and CO2. Although δ13C ratios indicated a prevalence of hydrogenotrophic methanogenesis, free energies of this process were small and often positive on the horizon scale, suggesting that methane was produced very locally. Fresh plant-derived carbon input apparently supported respiration in the rhizosphere and sustained methanogenesis in the unsaturated zone according to a 13C-CO2 labelling experiment. The study documents that drying and rewetting in a rich fen soil may have little effect on methanogenic pathways but result in rapid shifts between methanogenesis and methanotrophy. Such shifts may be promoted by roots and soil heterogeneity, as hydrogenotrophic methanogenesis occurred locally even when conditions were not conducive for this process in the bulk peat.
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Manzoni, Stefano, Arjun Chakrawal, Thomas Fischer, Joshua P. Schimel, Amilcare Porporato, and Giulia Vico. "Rainfall intensification increases the contribution of rewetting pulses to soil heterotrophic respiration." Biogeosciences 17, no. 15 (August 10, 2020): 4007–23. http://dx.doi.org/10.5194/bg-17-4007-2020.
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Abstract. Soil drying and wetting cycles promote carbon (C) release through large heterotrophic respiration pulses at rewetting, known as the “Birch” effect. Empirical evidence shows that drier conditions before rewetting and larger changes in soil moisture at rewetting cause larger respiration pulses. Because soil moisture varies in response to rainfall, these respiration pulses also depend on the random timing and intensity of precipitation. In addition to rewetting pulses, heterotrophic respiration continues during soil drying, eventually ceasing when soils are too dry to sustain microbial activity. The importance of respiration pulses in contributing to the overall soil heterotrophic respiration flux has been demonstrated empirically, but no theoretical investigation has so far evaluated how the relative contribution of these pulses may change along climatic gradients or as precipitation regimes shift in a given location. To fill this gap, we start by assuming that heterotrophic respiration rates during soil drying and pulses at rewetting can be treated as random variables dependent on soil moisture fluctuations, and we develop a stochastic model for soil heterotrophic respiration rates that analytically links the statistical properties of respiration to those of precipitation. Model results show that both the mean rewetting pulse respiration and the mean respiration during drying increase with increasing mean precipitation. However, the contribution of respiration pulses to the total heterotrophic respiration increases with decreasing precipitation frequency and to a lesser degree with decreasing precipitation depth, leading to an overall higher contribution of respiration pulses under future more intermittent and intense precipitation. Specifically, higher rainfall intermittency at constant total rainfall can increase the contribution of respiration pulses up to ∼10 % or 20 % of the total heterotrophic respiration in mineral and organic soils, respectively. Moreover, the variability of both components of soil heterotrophic respiration is also predicted to increase under these conditions. Therefore, with future more intermittent precipitation, respiration pulses and the associated nutrient release will intensify and become more variable, contributing more to soil biogeochemical cycling.
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Kim, D. G., R. Vargas, B. Bond-Lamberty, and M. R. Turetsky. "Effects of soil rewetting and thawing on soil gas fluxes: a review of current literature and suggestions for future research." Biogeosciences Discussions 8, no. 5 (October 4, 2011): 9847–99. http://dx.doi.org/10.5194/bgd-8-9847-2011.
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Abstract. The rewetting of dry soils and the thawing of frozen soils are short-term, transitional phenomena in terms of hydrology and the thermodynamics of soil systems. The impact of these short-term phenomena on larger scale ecosystem fluxes has only recently been fully appreciated, and a growing number of studies show that these events affect various biogeochemical processes including fluxes of soil gases such as carbon dioxide (CO2), methane (CH4), nitrous oxide (N2O), ammonia (NH3) and nitric oxide (NO). Global climate models predict that future climatic change is likely to alter the frequency and intensity of drying-rewetting events and thawing of frozen soils, highlighting the importance of understanding how rewetting and thawing will influence soil gas fluxes. Here we summarize findings in a new database based on 338 studies conducted from 1956 to 2010, and highlight open research questions. The database revealed conflicting results following rewetting and thawing in various terrestrial ecosystems, ranging from large increases in gas fluxes to non-significant changes. An analysis of published field studies (n = 142) showed that after rewetting or thawing, CO2, CH4, N2O, NO and NH3 fluxes increase from pre-event fluxes following a power function, with no significant differenced among gases. We discuss possible mechanisms and controls that regulate flux responses, and note that a high temporal resolution of flux measurements is critical to capture rapid changes in gas fluxes after these soil perturbations. Finally, we propose that future studies should investigate the interactions between biological (i.e. microbial community and gas production) and physical (i.e. flux, diffusion, dissolution) changes in soil gas fluxes, and explore synergistic experimental and modelling approaches.
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Knorr, K. H., B. Glaser, and C. Blodau. "Fluxes and <sup>13</sup>C isotopic composition of dissolved carbon and pathways of methanogenesis in a fen soil exposed to experimental drought." Biogeosciences 5, no. 5 (October 28, 2008): 1457–73. http://dx.doi.org/10.5194/bg-5-1457-2008.
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Abstract. Peatlands contain a carbon stock of global concern and significantly contribute to the global methane burden. The impact of drought and rewetting on carbon cycling in peatland ecosystems is thus currently debated. We studied the impact of experimental drought and rewetting on intact monoliths from a temperate fen over a period of ~300 days, using a permanently wet treatment and two treatments undergoing drought for 50 days. In one of the mesocosms, vegetation had been removed. Net production of CH4 was calculated from mass balances in the peat and emission using static chamber measurements. Results were compared to 13C isotope budgets of CO2 and CH4 and energy yields of acetoclastic and hydrogenotrophic methanogenesis. Drought retarded methane production after rewetting for days to weeks and promoted methanotrophic activity. Based on isotope and flux budgets, aerobic soil respiration contributed 32–96% in the wet treatment and 86–99% in the other treatments. Drying and rewetting did not shift methanogenic pathways according to δ13C ratios of CH4 and CO2. Although δ13C ratios indicated a prevalence of hydrogenotrophic methanogenesis, free energies of this process were small and often positive on the horizon scale. This suggests that methane was produced very locally. Fresh plant-derived carbon input apparently supported respiration in the rhizosphere and sustained methanogenesis in the unsaturated zone, according to a 13C-CO2 labelling experiment. The study documents that drying and rewetting in a rich fen soil may have little effect on methanogenic pathways, but result in rapid shifts between methanogenesis and methanotrophy. Such shifts may be promoted by roots and soil heterogeneity, as hydrogenotrophic methanogenesis occurred locally even when conditions were not conducive for this process in the bulk peat.
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Tripathi, M. K., K. C. Sahu, G. Karapetsas, K. Sefiane, and O. K. Matar. "Non-isothermal bubble rise: non-monotonic dependence of surface tension on temperature." Journal of Fluid Mechanics 763 (December 10, 2014): 82–108. http://dx.doi.org/10.1017/jfm.2014.659.
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AbstractWe study the motion of a bubble driven by buoyancy and thermocapillarity in a tube with a non-uniformly heated walls, containing a so-called ‘self-rewetting fluid’; the surface tension of the latter exhibits a parabolic dependence on temperature, with a well-defined minimum. In the Stokes flow limit, we derive the conditions under which a spherical bubble can come to rest in a self-rewetting fluid whose temperature varies linearly in the vertical direction, and demonstrate that this is possible for both positive and negative temperature gradients. This is in contrast to the case of simple fluids whose surface tension decreases linearly with temperature, for which bubble motion is arrested only for negative temperature gradients. In the case of self-rewetting fluids, we propose an analytical expression for the position of bubble arrestment as a function of other dimensionless numbers. We also perform direct numerical simulation of axisymmetric bubble motion in a fluid whose temperature increases linearly with vertical distance from the bottom of the tube; this is done for a range of Bond and Galileo numbers, as well as for various parameters that govern the functional dependence of surface tension on temperature. We demonstrate that bubble motion can be reversed and then arrested only in self-rewetting fluids, and not in linear fluids, for sufficiently small Bond numbers. We also demonstrate that considerable bubble elongation is possible under significant wall confinement, and for strongly self-rewetting fluids and large Bond numbers. The mechanisms underlying the phenomena observed are elucidated by considering how the surface tension dependence on temperature affects the thermocapillary stresses in the flow.
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Lohmann, Patrick, Simon Benk, Gerd Gleixner, Karin Potthast, Beate Michalzik, Nico Jehmlich, and Martin von Bergen. "Seasonal Patterns of Dominant Microbes Involved in Central Nutrient Cycles in the Subsurface." Microorganisms 8, no. 11 (October 30, 2020): 1694. http://dx.doi.org/10.3390/microorganisms8111694.
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Microbial communities play a key role for central biogeochemical cycles in the subsurface. Little is known about whether short-term seasonal drought and rewetting events influence the dominant microbes involved in C- and N-cycles. Here, we applied metaproteomics at different subsurface sites in winter, summer and autumn from surface litter layer, seepage water at increasing subsoil depths and remote located groundwater from two wells within the Hainich Critical Zone Exploratory, Germany. We observed changes in the dominance of microbial families at subsurface sampling sites with increasing distances, i.e., Microcoleaceae dominated in topsoil seepage, while Candidatus Brocadiaceae dominated at deeper and more distant groundwater wells. Nitrifying bacteria showed a shift in dominance from drought to rewetting events from summer by Nitrosomandaceae to autumn by Candidatus Brocadiaceae. We further observed that the reductive pentose phosphate pathway was a prominent CO2-fixation strategy, dominated by Woeseiaceae in wet early winter, which decreased under drought conditions and changed to a dominance of Sphingobacteriaceae under rewetting conditions. This study shows that increasing subsurface sites and rewetting event after drought alter the dominances of key subsurface microbes. This helps to predict the consequences of annual seasonal dynamics on the nutrient cycling microbes that contribute to ecosystem functioning.
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Khotimah, Gina Khusnul, Sigit Sutikno, and Indradi Wijatmiko. "Analisis Pengaruh Penyekatan Kanal Untuk Untuk Pembahasan Lahan Gambut Tropis." Rekayasa Sipil 14, no. 2 (June 25, 2020): 129–35. http://dx.doi.org/10.21776/ub.rekayasasipil.2020.014.02.7.
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Peatlands rewetting for hydrological restoration plays an important role for fire prevention and peatland restoration of degraded peatland. One of the methods for the rewetting is canal blocking. The impact of canal blocking for peatland rewetting is further analyzed in this research. This study focused in Pulau Tebing Tinggi peatland hydrological unit (PHU), which is located in Kepulauan Meranti Regency, Riau Province. To analysis the rewetting impact, 15 dipwells were installed with the distance of 1 m, 51 m, 101 m, 201 and 301 m from the canal for each transect of the three transects. A transect was set in the downstream and two transects were set in the upstream of canal block. The ground water level (GWL) in the 15 dipwells was recorded using water-loggers for one year. This research found that canal blocking has a good effect on maintaining groundwater levels and keeping peatlands in always wet or humid conditions up to a distance of 201 m perpendicular to the canal if the rise in water level in the canal due to canal blocking is more than 0.6 m. It is able to maintain the ground water depth in peatlands around 0.4 m, where the peatlands become low risk to the fire, emission rates and subsidence.
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Xu, Gang, Jiawei Song, Yang Zhang, and Yingchun Lv. "Effects of biochar application on soil organic carbon mineralization during drying and rewetting cycles." BioResources 14, no. 4 (October 31, 2019): 9957–67. http://dx.doi.org/10.15376/biores.14.4.9957-9967.
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Intense droughts and extreme precipitation events are likely to occur more frequently with global climate change. These drying-rewetting (DW) cycles affect the soil carbon (C) cycle. Biochar addition are reported to affect SOC mineralization and soil organic carbon (SOC) storage. However, the effects of biochar application on SOC mineralization during DW cycles are poorly understood. Two wheat straw (WS25) biochar produced at 300 °C (WS300) and 600 °C (WS600) were used to explore the effects of biochar on SOC mineralization under artificial DW cycles as compared to constant moisture (CM). It was found that biochar had different effects on SOC mineralization depending on biochar type or drying/rewetting period of DW cycles. Just like CK and WS25, WS600 application decreased SOC mineralization under DW cycles compared to CM. To some extent, SOC mineralization during DW cycles was similar to CM for WS300. The results suggested that WS300 addition diminished the reducing effect of DW cycle on SOC mineralization. In addition, biochar exhibited different effects on SOC mineralization depending on the drying and rewetting period under DW cycles. Biochar (WS300) addition during the drying period had less effect on SOC mineralization but increased the flush effect of SOC mineralization during the rewetting period. In conclusions, biochar application significantly affect SOC mineralization following DW cycles.
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Shirani, F., MR Malekipour, V. Sakhaei Manesh, and F. Aghaei. "Hydration and Dehydration Periods of Crown Fragments Prior to Reattachment." Operative Dentistry 37, no. 5 (September 1, 2012): 501–8. http://dx.doi.org/10.2341/10-130-l.
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SUMMARY Introduction Tooth fragment bonding is an excellent treatment option in dealing with traumatic injuries of the anterior teeth. Rewetting the tooth fragment has been shown to increase restoration durability. The present study examined the effect various dry and wet storage periods had on the reattached fragment's bond to the tooth. Materials and Methods One hundred and eight human mandibular incisors were fractured and assigned to undergo a dehydration period of 30 minutes, six hours, 24 hours, or three days before the rewetting procedure. After fracturing the teeth and drying the fragments, each of the specimens was assigned to one of the three main groups (A, B, or C) intended to evaluate the effect of different rehydration periods. Groups A and B underwent a 30-minute and a 24-hour rewetting period, respectively. Group C served as a control (without a rewetting stage). Tooth fragments were then reattached and prepared for the strength test. Force was applied on the lingual side of the tooth at a 1 mm/min rate until failure. Results The mean loads (N) required to fracture the restored teeth were as follows: 204.43 ± 33.48 N, 322.59 ± 34.62 N, and 253.25 ± 29.05 N for groups A, B, and C, respectively. Two-way analysis of variance (p<0.05) showed that rehydration and dehydration periods as well as their interaction caused significant differences in the strength of the final restoration. Multiple comparison tests showed that, in general, significant differences were not seen among different dehydration times prior to the rewetting stage (p>0.05), except in the case of the 30-minute dehydrated specimens (p<0.05). Conclusion Compared to a 30-minute period, a 24-hour rehydration of the tooth fragment before treatment seems to salvage enough moisture to result in an increase in reattachment strength.
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Pineda-Morante, David, José María Fernández-Calero, Sebastian Pölsterl, David Cunillera-Montcusí, Núria Bonada, and Miguel Cañedo-Argüelles. "Local hydrological conditions and spatial connectivity shape invertebrate communities after rewetting in temporary rivers." Hydrobiologia 849, no. 6 (January 20, 2022): 1511–30. http://dx.doi.org/10.1007/s10750-022-04799-8.
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AbstractTemporary rivers (TRs) dominate global river networks and are increasing in occurrence and spatiotemporal extent. However, few studies have investigated the communities that establish after rewetting events (i.e. the end of the dry phase), when local hydrological conditions can shape the communities through species sorting, and the spatial connectivity of sites can also influence colonisation. Here, we analysed the relative importance of both local hydrological conditions and spatial connectivity on the invertebrate communities of seven not impacted Mediterranean TRs after rewetting. We quantified the frequency and duration of drying events and the time since flow resumed. We also quantified spatial connectivity based on each site’s position in the river network (i.e. network connectivity) and the presence of nearby disconnected streams. Overall, we found that both hydrological conditions and network connectivity played a significant role in structuring aquatic invertebrate communities after rewetting. Taxonomic richness, functional richness and functional redundancy decreased with the frequency and duration of drying events and increased with time since the most recent rewetting. Network connectivity showed a significant unimodal relationship with taxonomic and functional metrics. In contrast, the presence of nearby disconnected streams was negatively related to functional richness and functional dispersion. Given that flow intermittence in Mediterranean areas is expected to intensify under future global change scenarios, our results can be helpful to guide future conservation and management actions.
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Peng, X. F., and G. P. Peterson. "Analysis of Rewetting for Surface Tension Induced Flow." Journal of Heat Transfer 114, no. 3 (August 1, 1992): 703–7. http://dx.doi.org/10.1115/1.2911337.
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An analytical investigation was conducted to determine the rewetting characteristics of thin, surface tension driven liquid films over heated plates as a function of the fluid properties, the film thickness, and the applied heat flux. Analytical expressions for the maximum sustainable heat flux and the rewetting velocity were developed for both flat and grooved plates and were compared with data from previous investigations. The results indicated good agreement for low film velocities; however, at high velocities the experimental data deviated significantly from the theoretical predictions. It was hypothesized that this deviation was due to the presence of liquid sputtering near the liquid front. To compensate for this liquid sputtering, the expressions for maximum sustainable heat flux and rewetting velocity were modified using an empirical correction factor developed from the data of previous thin film thickness investigations. The resulting modified expressions were found to compare very favorably with available experimental data over a large range of flow conditions and velocities.
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Hasanah, Ainun, and Muhammad Farouk Setiawan. "REWETTING DESIGN FOR TROPICAL PEATLAND RESTORATION." Sociae Polites 21, no. 2 (December 9, 2020): 111–25. http://dx.doi.org/10.33541/sp.v21i3.2245.
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Peatlands located in tropical climates are estimated to have an area of 11% of the total peatland on earth. The scope of tropical peatland is proportional to the significant role this ecosystem plays in the stability of the earth and everything in it. Various efforts have been made to restore the condition of the peatland ecosystem, especially in tropical areas that have been affected by human activities. This study using the literature review method attempts to collect and summarize various peatland restoration efforts carried out in various countries in the world, then serve as a reference and basis for consideration in redesigning peat rewetting infrastructure. The result of this study is a canal blocking design using a PVC pipe filled with peat soil in its cavity. The layout of this PVC pipe canal blocking is designed by considering various factors. Challenges and prospects related to the idea of this canal blocking with PVC pipe were also taken into consideration in the design. It is hoped that the innovation of canal blocking materials can increase resource efficiency and fund for canal blocking construction while maintaining its function and development objectives.
Keywords: peatland rewetting design, canal blocking, PVC pipe
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Mao, C. Q., R. Farnood, and J. K. Spelt. "Local rewetting and distortion of paper." Nordic Pulp & Paper Research Journal 18, no. 1 (January 1, 2003): 10–17. http://dx.doi.org/10.3183/npprj-2003-18-01-p010-017.
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Åslund, Peter, Hannes Vomhoff, and Alexander Waljanson. "External rewetting after suction box dewatering." Nordic Pulp & Paper Research Journal 23, no. 4 (December 1, 2008): 409–14. http://dx.doi.org/10.3183/npprj-2008-23-04-p409-414.
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P. Shatadal, D. S. Jayas, and N. D. G. White. "THIN-LAYER REWETTING CHARACTERISTICS OF CANOLA." Transactions of the ASAE 33, no. 3 (1990): 0871–76. http://dx.doi.org/10.13031/2013.31412.
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Batson, W., Y. Agnon, and A. Oron. "Thermocapillary modulation of self-rewetting films." Journal of Fluid Mechanics 819 (April 27, 2017): 562–91. http://dx.doi.org/10.1017/jfm.2017.191.
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Whereas surface tension decreases linearly with temperature for most fluids, here we consider those that exhibit a well-defined minimum. Specifically, our study is motivated by dilute aqueous mixtures of long-chain alcohols, for which surface tension is typically assumed to be a quadratic function of temperature. Utilization of these so-called ‘self-rewetting fluids’ has grown significantly in the past decade, due to observations that heat transfer is enhanced in applications such as film boiling and pulsating heat pipes. With similar applications in mind, we investigate the dynamics of a thin film with quadratic surface tension which is subjected to a temperature modulation in the bounding gas. A model is developed within the framework of the long-wave approximation, and a time-averaged thermocapillary driving force for destabilization is uncovered that results from the nonlinear surface tension. Linear stability analysis of the nonlinear partial differential equation for the film thickness is used to determine the critical conditions at which this driving force destabilizes the film and numerical investigation of this evolution equation reveals that linearly unstable perturbations saturate to regular periodic solutions (when the modulational frequency is set properly). Properties of these flows such as bifurcation at critical points and long-domain flows, where multiple unstable linear modes interact, are also discussed.
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ABE, Y. "Self-Rewetting Fluids: Beneficial Aqueous Solutions." Annals of the New York Academy of Sciences 1077, no. 1 (September 1, 2006): 650–67. http://dx.doi.org/10.1196/annals.1362.026.
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Carbajo, Juan J. "A study on the rewetting temperature." Nuclear Engineering and Design 84, no. 1 (January 1985): 21–52. http://dx.doi.org/10.1016/0029-5493(85)90310-3.
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Lowther, Gerald E. "Rewetting drops/artificial tears—what works?" International Contact Lens Clinic 17, no. 7-8 (July 1990): 164–65. http://dx.doi.org/10.1016/0892-8967(90)90001-v.
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Abe, Yoshiyuki, Akira Iwaski, and Kotaro Tanaka. "Thermal management with self-rewetting fluids." Microgravity - Science and Technology 16, no. 1-4 (March 2005): 148–52. http://dx.doi.org/10.1007/bf02945966.
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Debbarma, A., and K. M. Pandey. "Influence on rewetting temperature and wetting delay during rewetting rod bundle by various radial jet models." Kerntechnik 81, no. 1 (March 16, 2016): 50–59. http://dx.doi.org/10.3139/124.110571.
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Azizan, Siti Noor Fitriah, Yuji Goto, Toshihiro Doi, Muhammad Imran Firdaus Kamardan, Hirofumi Hara, Iain McTaggart, Takamitsu Kai, and Kosuke Noborio. "Comparing GHG Emissions from Drained Oil Palm and Recovering Tropical Peatland Forests in Malaysia." Water 13, no. 23 (November 29, 2021): 3372. http://dx.doi.org/10.3390/w13233372.
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For agricultural purposes, the drainage and deforestation of Southeast Asian peatland resulted in high greenhouse gases’ (GHGs, e.g., CO2, N2O and CH4) emission. A peatland regenerating initiative, by rewetting and vegetation restoration, reflects evidence of subsequent forest recovery. In this study, we compared GHG emissions from three Malaysian tropical peatland systems under the following different land-use conditions: (i) drained oil palm plantation (OP), (ii) rewetting-restored forest (RF) and (iii) undrained natural forest (NF). Biweekly temporal measurements of CO2, CH4 and N2O fluxes were conducted using a closed-chamber method from July 2017 to December 2018, along with the continuous measurement of environmental variables and a one-time measurement of the soil physicochemical properties. The biweekly emission data were integrated to provide cumulative fluxes using the trapezoidal rule. Our results indicated that the changes in environmental conditions resulting from draining (OP) or rewetting historically drained peatland (RF) affected CH4 and N2O emissions more than CO2 emissions. The cumulative CH4 emission was significantly higher in the forested sites (RF and NF), which was linked to their significantly higher water table (WT) level (p < 0.05). Similarly, the high cumulative CO2 emission trends at the RF and OP sites indicated that the RF rewetting-restored peatland system continued to have high decomposition rates despite having a significantly higher WT than the OP (p < 0.05). The highest cumulative N2O emission at the drained-fertilized OP and rewetting-restored RF sites was linked to the available substrates for high decomposition (low C/N ratio) together with soil organic matter mineralization that provided inorganic nitrogen (N), enabling ideal conditions for microbial mediated N2O emissions. Overall, the measured peat properties did not vary significantly among the different land uses. However, the lower C/N ratio at the OP and the RF sites indicated higher decomposition rates in the drained and historically drained peat than the undrained natural peat (NF), which was associated with high cumulative CO2 and N2O emissions in our study.
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Ručová, Dajana, Michal Goga, Marek Matik, and Martin Bačkor. "Adaptations of cyanobacterium Nostoc commune to environmental stress: Comparison of morphological and physiological markers between European and Antarctic populations after rehydration." Czech Polar Reports 8, no. 1 (January 1, 2018): 84–93. http://dx.doi.org/10.5817/cpr2018-1-6.
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Availability of water may influence activities of all living organisms, including cyanobacterial communities. Filamentous cyanobacterium Nostoc commune is well adapted to wide spectrum of ecosystems. For this reason, N. commune had to develop diverse protection strategies due to exposition to regular rewetting and drying processes. Few studies have been conducted on activities, by which cyanobacteria are trying to avoid water deficit. Therefore, the present study using physiological and morphological parameters is focused on comparison between European and Antarctic ecotypes of N. commune during rewetting. Gradual increase of FV/FM ratios, as the markers of active PS II, demonstrated the recovery processes of N. commune colonies from Europe as well as from Antarctica after time dependent rehydration. During the initial hours of rewetting, there was lower content of soluble proteins in colonies from Antarctica in comparison to those from Europe. Total content of nitrogen was higher in European ecotypes of N. commune. Significantly higher frequency of occurrence of heterocysts in Antarctic ecotypes was observed. The heterocyst cells were significantly longer in Antarctic ecotypes rather than European ecotypes of N. commune.
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Meissner, R., H. Rupp, J. Seeger, and P. Leinweber. "Strategies to mitigate diffuse phosphorus pollution during rewetting of fen peat soils." Water Science and Technology 62, no. 1 (July 1, 2010): 123–31. http://dx.doi.org/10.2166/wst.2010.277.
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The cultivation of fen peat soils (Eutric Histosols) for agricultural purposes, started in Europe about 250 years ago, resulting in decreased soil fertility, increased oxidation of peat and corresponding greenhouse gas fluxes to the atmosphere, nutrient transfer to aquatic ecosystems and losses in total area of the former native wetlands. To prevent these negative environmental effects set-aside programs and rewetting measures were promoted in recent years. Literature results and practical experiences showed that large scale rewetting of intensively used agricultural Histosols may result in mobilisation of phosphorus (P), its transport to adjacent surface waters and an accelerated eutrophication. The paper summarises results from an international European Community sponsored research project and demonstrates how results obtained at different scales and from different scientific disciplines were compiled to derive a strategy to carry out rewetting measures. Based on this findings a simple decision support system (DSS) for a hydrologically sensitive area in the Droemling catchment in north-eastern Germany was developed and since 2005 practically used to prevent freshwater resources from non point P pollution.
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Kumar, Mithilesh, D. Mukhopadhyay, A. K. Ghosh, and Ravi Kumar. "Numerical Study on Influence of Cross Flow on Rewetting of AHWR Fuel Bundle." Scientific World Journal 2014 (2014): 1–10. http://dx.doi.org/10.1155/2014/589543.
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Numerical study on AHWR fuel bundle has been carried out to assess influence of circumferential and cross flow rewetting on the conduction heat transfer. The AHWR fuel bundle quenching under accident condition is designed primarily with radial jets at several axial locations. A 3D (r,θ,z) transient conduction fuel pin model has been developed to carry out the study with a finite difference method (FDM) technique with alternating direction implicit (ADI) scheme. The single pin has been considered to study effect of circumferential conduction and multipins have been considered to study the influence of cross flow. Both analyses are carried out with the same fluid temperature and heat transfer coefficients as boundary conditions. It has been found from the analyses that, for radial jet, the circumferential conduction is significant and due to influence of overall cross flow the reductions in fuel temperature in the same quench plane in different rings are different with same initial surface temperature. Influence of cross flow on rewetting is found to be very significant. Outer fuel pins rewetting time is higher than inner.
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Agrienvi. "Reri Yulianti*, Yanciluk, Santosa Yulianto, Penyang, Erwyn." Agrienvi: Jurnal Ilmu Pertanian 13, no. 02 (October 8, 2020): 9–21. http://dx.doi.org/10.36873/aev.v13i02.1770.
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Rewetting program especially canal blocking (tabat) carried out by the Peat Restoration Agency (BRG) in 2017 aspart of efforts to control forest and land fires that often hit peatlands including in Kalawa Village in 2014 and 2015. Theresults of this study indicate that 7 indicators from 3 research variables for the level of land owners participation in thegroup receiving the rewetting program shows 14.28% has very strong/very high correlation (design making/constructionmodel), 42.86% has strong/high correlation (frequency of socialization, numbers of attendance, socialization method),42.86% has strong enough/high enough correlation (distance of land, placement of position/location, numbers of canalblocking). Whereas for 9 indicators from 4 research variables, the level of land owners participation in the group rejectingthe rewetting program shows 22.22% has strong/high correlation (age, land area), and 77.78% has quite strong/highenough correlation (level of education, distance of land, frequency of socialization, number of attendance, method ofsocialization, construction design/modeling, placement of position/location of canal blocking). The level of land ownersparticipation in the BRG rewetting program through canal blocking (tabat) was dominated by the medium category(36.0%) for the group receiving the program and the low category (48.0%) for the group rejecting the program. Therelatively similar characteristics of the two community groups and have a major influence on the level of land ownersparticipation are socialization efforts (frequency of socialization, numbers of attendance, socialization method), andproject implementation (design making/construction model, placement of positions/location of canal blocking).Keywords: participation; land owners; canal blocking (tabat); handel; peatland.
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Aanderud, Zachary T., and Jay T. Lennon. "Validation of Heavy-Water Stable Isotope Probing for the Characterization of Rapidly Responding Soil Bacteria." Applied and Environmental Microbiology 77, no. 13 (May 6, 2011): 4589–96. http://dx.doi.org/10.1128/aem.02735-10.
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ABSTRACTRapid responses of bacteria to sudden changes in their environment can have important implications for the structure and function of microbial communities. In this study, we used heavy-water stable isotope probing (H218O-SIP) to identify bacteria that respond to soil rewetting. First, we conducted experiments to address uncertainties regarding the H218O-SIP method. Using liquid chromatography-mass spectroscopy (LC-MS), we determined that oxygen from H218O was incorporated into all structural components of DNA. Although this incorporation was uneven, we could effectively separate18O-labeled and unlabeled DNAs derived from laboratory cultures and environmental samples that were incubated with H218O. We found no evidence forex vivoexchange of oxygen atoms between DNA and extracellular H2O, suggesting that18O incorporation into DNA is relatively stable. Furthermore, the rate of18O incorporation into bacterial DNA was high (within 48 to 72 h), coinciding with pulses of CO2generated from soil rewetting. Second, we examined shifts in the bacterial composition of grassland soils following rewetting, using H218O-SIP and bar-coded pyrosequencing of 16S rRNA genes. For some groups of soil bacteria, we observed coherent responses at a relatively course taxonomic resolution. Following rewetting, the relative recovery ofAlphaproteobacteria,Betaproteobacteria, andGammaproteobacteriaincreased, while the relative recovery ofChloroflexiandDeltaproteobacteriadecreased. Together, our results suggest that H218O-SIP is effective at identifying metabolically active bacteria that influence soil carbon dynamics. Our results contribute to the ecological classification of soil bacteria while providing insight into some of the functional traits that influence the structure and function of microbial communities under dynamic soil moisture regimes.
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Trounson, Mary E., John R. McLaughlin, and Peter W. Robinson. "Surfactant Solution Transport in Wool Yarn." Textile Research Journal 58, no. 8 (August 1988): 455–62. http://dx.doi.org/10.1177/004051758805800805.
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Surfactant solution transport rates were measured on wool yarn scoured or otherwise treated with various nonylphenol poly(ethylene oxide) (NPEO) surfactants or with the sodium salt of dioctyl sulfosuccinate. The EO chain length of the NPEO used to scour the yarn had a significant effect on the diffusivity coefficient, although not on the residual contaminant level or the color. Surfactants applied as prewetting or rewetting agents increased the diffusivity coefficients. Prewetting gives the faster solution transport rates, and the temperature of application and the wet add-on are important. The effectiveness of a rewetting agent is related to its rate of solution.
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Mcgechan, M. B., and R. Graham. "The Rewetting of Partially Dried Grass Swaths by Rain: Part 3, Laboratory Investigation into the Rewetting Process." Journal of Agricultural Engineering Research 55, no. 1 (May 1993): 45–56. http://dx.doi.org/10.1006/jaer.1993.1031.
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Kaden, Ute Susanne, Elmar Fuchs, Christian Hecht, Thomas Hein, Holger Rupp, Mathias Scholz, and Christiane Schulz-Zunkel. "Advancement of the Acetylene Inhibition Technique Using Time Series Analysis on Air-Dried Floodplain Soils to Quantify Denitrification Potential." Geosciences 10, no. 11 (October 29, 2020): 431. http://dx.doi.org/10.3390/geosciences10110431.
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Denitrification in floodplain soils is one key process that determines the buffering capacity of riparian zones in terms of diffuse nitrate pollution. One widely used approach to measure the denitrification potential is the acetylene inhibition technique that requires fresh soil samples. We conducted experiments with air-dried soils using a time series analysis to determine the optimal rewetting period. Thus, air-dried soil samples from six different floodplain areas in Germany were rewetted for 1 to 13days to 100% water-filled pore space. We analyzed nitrogen accumulated as N2O in the top of anaerobic flasks with and without acetylene by gas chromatography after four hours of incubation. We observed an overall optimal rewetting of at least seven days for complete denitrification. We also saw the strong influence of pH and field capacity on the denitrification product ratio; in soils with pH < 7, we hardly assumed complete denitrification, whereas the treatments with pH > 7 achieved stable values after seven days of rewetting. This advanced method provides the opportunity to carry out campaigns with large soil sample sizes on the landscape scale, as samples can be stored dry until measurements are taken.
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Rubarenzya, Mark, Jan Staes, Patrick Willems, Jean Berlamont, and Patrick Meire. "Modelling in support of an interdisciplinary approach to ecosystem restitution." Annals of Warsaw University of Life Sciences - SGGW. Land Reclamation 38, no. 1 (January 1, 2007): 139–50. http://dx.doi.org/10.2478/v10060-008-0030-5.
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Modelling in support of an interdisciplinary approach to ecosystem restitution This paper reports on a study being undertaken to analyze the potential effects of rewetting when undertaken for the restitution of the catchment ecosystem of the Grote Nete catchment. In bringing together the expertise of both ecological and hydrological modelers, this study aims at ensuring that the science being performed is immediately relevant from both the environmental management and the socio-political perspectives. Like many European catchments, Grote Nete has been experiencing an increase in extreme hydrological events. In addition, there has been a decline in the ecological value of the catchment ecosystem. The problem is considered to be a conflict of interests arising between urban/agricultural and nature conservation needs. Rewetting has been considered as a possible intervention to reverse these trends. However, a shortcoming with rewetting is that the hydrological consequences remain largely unknown. A numerical model has been developed to study these potential effects. A land use model, SPAN was developed and coupled to a physically-based, fully distributed model (MIKE SHE) to complete an ecohydrological model. The paper describes the development of the model.