scholarly journals Testing the effects of basic numerical implementations of water migration on models of subduction dynamics

Solid Earth ◽  
2014 ◽  
Vol 5 (1) ◽  
pp. 537-555 ◽  
Author(s):  
M. E. T. Quinquis ◽  
S. J. H. Buiter
Keyword(s):  
Upper Mantle ◽  
Water Distribution ◽  
Mantle Wedge ◽  
Bound Water ◽  
Free Water ◽  
Water Velocity ◽  
Water Migration ◽  
Creep Flow ◽  
Dehydration Reactions ◽  
Slab Dehydration

Abstract. Subduction of oceanic lithosphere brings water into the Earth's upper mantle. Previous numerical studies have shown how slab dehydration and mantle hydration can impact the dynamics of a subduction system by allowing a more vigorous mantle flow and promoting localisation of deformation in the lithosphere and mantle. The depths at which dehydration reactions occur in the hydrated portions of the slab are well constrained in these models by thermodynamic calculations. However, computational models use different numerical schemes to simulate the migration of free water. We aim to show the influence of the numerical scheme of free water migration on the dynamics of the upper mantle and more specifically the mantle wedge. We investigate the following three simple migration schemes with a finite-element model: (1) element-wise vertical migration of free water, occurring independent of the flow of the solid phase; (2) an imposed vertical free water velocity; and (3) a Darcy velocity, where the free water velocity is a function of the pressure gradient caused by the difference in density between water and the surrounding rocks. In addition, the flow of the solid material field also moves the free water in the imposed vertical velocity and Darcy schemes. We first test the influence of the water migration scheme using a simple model that simulates the sinking of a cold, hydrated cylinder into a dry, warm mantle. We find that the free water migration scheme has only a limited impact on the water distribution after 1 Myr in these models. We next investigate slab dehydration and mantle hydration with a thermomechanical subduction model that includes brittle behaviour and viscous water-dependent creep flow laws. Our models demonstrate that the bound water distribution is not greatly influenced by the water migration scheme whereas the free water distribution is. We find that a bound water-dependent creep flow law results in a broader area of hydration in the mantle wedge, which feeds back to the dynamics of the system by the associated weakening. This finding underlines the importance of using dynamic time evolution models to investigate the effects of (de)hydration. We also show that hydrated material can be transported down to the base of the upper mantle at 670 km. Although (de)hydration processes influence subduction dynamics, we find that the exact numerical implementation of free water migration is not important in the basic schemes we investigated. A simple implementation of water migration could be sufficient for a first-order impression of the effects of water for studies that focus on large-scale features of subduction dynamics.

scholarly journals Testing the effects of the numerical implementation of water migration on models of subduction dynamics

2013 ◽  
Vol 5 (2) ◽  
pp. 1771-1815 ◽  
Author(s):  
M. E. T. Quinquis ◽  
S. J. H. Buiter
Keyword(s):  
Upper Mantle ◽  
Material Flow ◽  
Water Distribution ◽  
Mantle Wedge ◽  
Free Water ◽  
Water Velocity ◽  
Numerical Implementation ◽  
Water Migration ◽  
Creep Flow ◽  
Slab Dehydration

Abstract. Subduction of oceanic lithosphere brings water into Earth's upper mantle. Previous numerical studies have shown how slab dehydration and mantle hydration can impact the dynamics of a subduction system by allowing a more vigorous mantle flow and promoting localisation of deformation in lithosphere and mantle. The depths at which dehydration reactions occur in the hydrated portions of the slab are well constrained in these models by thermodynamic calculations. However, the mechanism by which free water migrates in the mantle is incompletely known. Therefore, models use different numerical schemes to model the migration of free water. We aim to show the influence of the numerical scheme of free water migration on the dynamics of the upper mantle and more specifically the mantle wedge. We investigate the following three migration schemes with a finite-element model: (1) element-wise vertical migration of free water, occurring independent of the material flow; (2) an imposed vertical free water velocity; and (3) a Darcy velocity, where the free water velocity is calculated as a function of the pressure gradient between water and the surrounding rocks. In addition, the material flow field also moves the free water in the imposed vertical velocity and Darcy schemes. We first test the influence of the water migration scheme using a simple Stokes flow model that simulates the sinking of a cold hydrated cylinder into a hot dry mantle. We find that the free water migration scheme has only a limited impact on the water distribution after 1 Myr in these models. We next investigate slab dehydration and mantle hydration with a thermomechanical subduction model that includes brittle behaviour and viscous water-dependent creep flow laws. Our models show how the bound water distribution is not greatly influenced by the water migration scheme whereas the free water distribution is. We find that a water-dependent creep flow law results in a broader area of hydration in the mantle wedge which feeds back to the dynamics of the system by the associated weakening. This supports using dynamic time evolution models to investigate the effects of (de)hydration. We also show that hydrated material can be transported down to the base of the upper mantle at 670 km. Although (de)hydration processes influence subduction dynamics, we find that the exact numerical implementation of free water migration is not important. This implies that a simple implementation of water migration would be sufficient for studies that focus on larger-scale features of subduction dynamics.

scholarly journals Measurement and Modelling of Moisture Distribution and Water Binding Energy of Dredged Sludge

Water ◽  
2020 ◽  
Vol 12 (12) ◽  
pp. 3395
Author(s):  
Feiyan Mao ◽  
Yingjie Zhao ◽  
Yiping Zhang ◽  
Zhou Chen ◽  
Lu Yin
Keyword(s):  
Binding Energy ◽  
Water Distribution ◽  
Bound Water ◽  
Free Water ◽  
Moisture Distribution ◽  
Water Binding ◽  
Dredged Sludge ◽  
Urban Watercourse ◽  
Experimental Values ◽  
Stage 1

The dewatering of dredged sludge is a critical step in the minimization and reutilization of this solid waste. However, there is a lack of available literature on the fundamental drying characteristics of dredged sludge. In this work, two kinds of typical sludge dredged from an urban watercourse were tested by low-field NMR to investigate the water distribution in sludge and it was found that water contained in sludge can be classified into three categories: free water, capillary water and bound water. In addition, a novel model was proposed based on the Lennard-Jones equation and Kelvin law to quantitatively evaluate the binding energy during drying. Further, the model results were experimentally verified by thermogravimetry differential thermal analysis (TG-DTA). Results show that the trends of the model are consistent with the experimental values and the gradient of energy consumption during dehydration can be divided into three main stages. In stage 1, the total energy required for dewatering equals the latent heat of free water. In stage 2, binding energy reaches dozens to hundreds of kJ/kg accounting for capillary action. In stage 3, binding energy increases steeply reaching almost thousands of kJ/kg due to intermolecular interactions. All the discovered aspects could improve the management and disposal of dredged sludge from an energy cost perspective.

scholarly journals The influence of wheat bran and pectin on the distribution of water in rat caecal contents and faeces

1993 ◽  
Vol 69 (3) ◽  
pp. 913-920 ◽  
Author(s):  
Elizabeth F. Armstrong ◽  
Martin A. Eastwood ◽  
W. Gordon Brydon
Keyword(s):  
Wheat Bran ◽  
Water Distribution ◽  
Bound Water ◽  
Free Water ◽  
Basal Diet ◽  
Dry Weight ◽  
Residual Water ◽  
Faecal Weight ◽  
Water Holding

Wheat bran and pectin (100 g/kg) were added to a basal diet and fed to rats. An in vitro dialysis technique was used to measure the distribution of caecal and faecal water between the bound, i.e. that held by bacteria and undigested macromolecules, and free water. Bran increased wet (67%) and dry (74%) faecal weight. Pectin increased wet faecal weight (59 %), but did not influence dry weight. In faeces both bran and pectin increased the amount of total and bound water, but only pectin increased total and bound water when expressed on a dry weight basis. Caecal wet (90%) and dry (67%) weights increased with pectin but not with bran. Bran did not change total water but increased bound water whereas pectin increased both. This suggests that water contributed more to the increase in stool bulk in the pectin- supplemented animals due to free and bound water associated with both increased numbers of bacteria and residual pectin. Pectin altered the distribution of water in faeces. Bran has no effect on water distribution and is only partly fermented. The residual water-holding capacity leads to an increased wet and dry stool output.

scholarly journals Influence of Electron Beam Irradiation on the Moisture and Properties of Freshly Harvested and Sun-Dried Rice

Foods ◽  
2020 ◽  
Vol 9 (9) ◽  
pp. 1139 ◽  
Author(s):  
Lihong Pan ◽  
Jiali Xing ◽  
Xiaohu Luo ◽  
Yanan Li ◽  
Dongling Sun ◽  
...  
Keyword(s):  
Electron Beam ◽  
Rheological Properties ◽  
Water Distribution ◽  
Electron Beam Irradiation ◽  
Low Dose ◽  
Bound Water ◽  
Free Water ◽  
Textural Properties ◽  
Rice Starch ◽  
Beam Irradiation

Moisture content is an important factor that affects rice storage. Rice with high moisture (HM) content has superior taste but is difficult to store. In this study, low-dose electron beam irradiation (EBI) was used to study water distribution in newly harvested HM (15.03%) rice and dried rice (11.97%) via low-field nuclear magnetic resonance (LF-NMR). The gelatinization, texture and rheological properties of rice and the thermal and digestion properties of rice starch were determined. Results showed that low-dose EBI could change water distribution in rice mainly by affecting free water under low-moisture (LM) conditions and free water and bound water under HM conditions. HM rice showed smooth changes in gelatinization and rheological properties and softened textural properties. The swelling power and solubility index indicated that irradiation promoted the depolymerization of starch chains. Overall, low-dose EBI had little effect on the properties of rice. HM rice showed superior quality and taste, whereas LM rice exhibited superior nutritional quality. This work attempted to optimize the outcome of the EBI treatment of rice for storage purposes by analyzing its effects. It demonstrated that low-dose EBI was more effective and environmentally friendly than other techniques.

Influence of the free water content on the dewaterability of sewage sludges

2001 ◽  
Vol 44 (10) ◽  
pp. 177-183 ◽  
Author(s):  
J. Kopp ◽  
N. Dichtl
Keyword(s):  
Binding Energy ◽  
Sewage Sludge ◽  
Water Content ◽  
Water Distribution ◽  
Bound Water ◽  
Free Water ◽  
Binding Energies ◽  
Intracellular Water ◽  
Water Binding ◽  
Free Water Content

Dewaterabilty of sewage depends on the physical water distribution. The various types of water in sewage sludge are mainly distinguished by type and intensity of their physical bonding to the solids. In a sewage sludge suspension different types of water can be distinguished. These are free water, which is not bound to the particles, interstitial water, which is bound by capillary forces between the sludge flocs, surface water, which is bound by adhesive forces and intracellular water. Only free water can be separated during mechanical dewatering. It can be shown, that thermo-gravimteric measurement of the free water content leads to an exact prediction of full-scale dewatering results. Maximum dewatering results are reached by separating all free water during centrifugation. Furthermore on the basis of the drying curve an estimation of water binding energies can be achieved. The binding energy for free water is less than 0,28 kJ/kg water. The binding energy for bound water (sum of surface and intracellular water) is higher than 5 kJ/kg water.

scholarly journals Low-Field NMR Analysis of Chicken Patties Prepared with Woody Breast Meat and Implications to Meat Quality

Foods ◽  
2021 ◽  
Vol 10 (10) ◽  
pp. 2499
Author(s):  
Xiao Sun ◽  
Jinjie You ◽  
Yan Dong ◽  
Ligen Xu ◽  
Clay J. Maynard ◽  
...  
Keyword(s):  
Water Distribution ◽  
Bound Water ◽  
Free Water ◽  
Breast Meat ◽  
Low Field ◽  
Moisture Variation ◽  
Protein Properties ◽  
Low Field Nmr ◽  
Water Ratio ◽  
Chicken Patties

The scope of this paper was to investigate the effects of water distribution differences on the quality and feasibility of chicken patties supplemented with woody breast (WB). Chicken patties, containing differing amounts of WB (0%, 25%, 50%, 75%, 100%) were analyzed using low-field NMR. Quality differences between chicken patties were further evaluated by combining lipid and protein properties, fry loss (FL), color (L*, a*, b*), texture (hardness, springiness, chewiness, cohesiveness, resilience), microstructure, and sensory characteristics. The results expressed that both lipid and protein oxidation increased and immobilized water in chicken patties can be converted to free water more easily with increasing levels of WB. Additionally, the free water ratio decreased, water freedom increased, and the bound water ratio increased (p < 0.05). Fry loss, color, texture (hardness, springiness, chewiness), microstructure, and sensory (character, organization, taste) characteristics deteriorated significantly when the WB inclusion level exceeded 25%. Particularly, characteristics of texture (chewiness and character) and sensory (character and organization) decreased significantly as WB inclusion increased past 25% (p < 0.01). Furthermore, fry loss, texture, and overall microstructure partially confirmed the moisture variation of chicken patties as the potential cause of the abnormal quality. Although the experimental data expressed that mixing to 35% WB inclusion was feasible, the practical and economic impact recommends inclusion levels to not exceed 30%.

Assessment of Bone Quality Associated With Loosely and Tightly Bound Water

2010 ◽  
Author(s):  
Qingwen Ni ◽  
Naniel P. Nicolella
Keyword(s):  
Bone Strength ◽  
Bone Quality ◽  
Water Distribution ◽  
Mechanical Test ◽  
Bound Water ◽  
Free Water ◽  
Water Molecules ◽  
Surface Charges ◽  
Mobile Water ◽  
Age Related

Previous studies have shown that the age-related increase in bone porosity results a decrease in bone strength, and porosity is related to the volume of mobile water in the pores. In addition, since water is also bound to collagen and mineral, changes in the amount of bound water will potentially affect the bone strength. It is known that the removal of the loosely bound water (via hydrogen bonding) requires less energy than the water molecules trapped inside collagen molecules, which in turn requires similar or less energy than water molecules bound to the surface charges of mineral apatite (more ionic in nature). Also, water that is imbedded in the lattice of hydroxyapatite (more covalent in nature) requires the highest energy to dislodge. However, there is no traditional method that can determine mobile and bound water, further for loosely and tightly bound ware accurately, non-destructively and non-invasively. Here, we propose that by using NMR Car-Purcell-Meiboom-Gill (CPMG) spin-spin relaxation measurement to determine the mobile water, and the NMR inversion T2-FID spectrum derived from NMR free induction decay (FID) measurements for estimating the bound and free water distribution. Furthermore, after comparison of the total water lost (weighing method) within tissue by using drying (free dry) on the air to the total mobile water lost measured by NMR CPMG method, then, the total loosely bound water lost can be estimated. Following this, the mechanical test will be used to evaluate the bone quality related to the tightly and loosely bound water within bone. This information can be used to further assessment of bone quality.

scholarly journals Whole Fish Powder Snacks: Evaluation of Structural, Textural, Pasting, and Water Distribution Properties

2021 ◽  
Vol 13 (11) ◽  
pp. 6010
Author(s):  
Asad Nawaz ◽  
Ibrahim Khalifa ◽  
Noman Walayat ◽  
Jose M. Lorenzo ◽  
Sana Irshad ◽  
...  
Keyword(s):  
Water Distribution ◽  
Microstructural Analysis ◽  
Bound Water ◽  
Free Water ◽  
Pasting Properties ◽  
Snack Food ◽  
Fish Waste ◽  
Low Field ◽  
Novel Method ◽  
Four Levels

Global fisheries production has increased up to ~200 MT, which has resulted in the intensive generation of waste or byproducts (~20 MT), which is creating serious problems for environmental management with zero income. This study proposes an idea of using whole fish (red and white meat, skin, bones, and fins but not scales) for human food (snack food) with the aim of zero waste generation. Whole fish powder (WFP) was prepared by a novel method (using freeze-drying as well as stone ball milling) and fortified in baked snacks at four levels (0, 5, 10, and 15% w/w of 100 g of formulation). The results revealed that the addition of WFP decreased expansion and color parameters compared to control. Hardness was significantly (p < 0.05) increased with the addition of WFP, which was attributed to the mineral content of WFP. Pasting properties determined by rapid visco analyzer (RVA) were dramatically decreased with the addition of 10–15% WFP, suggesting the weak interaction of starch and protein, which was also evidenced by scanning electron microscopy (SEM). Low field nuclear magnetic resonance (LF-NMR) analysis revealed that the amount of free water was increased when 10–15% WFP was added in snacks while bound water was highest in control and 5% WFP samples, respectively. The microstructural analysis by SEM showed that the protein network was increased in those samples incorporated with WFP compared to control that had more starch granules. The results suggest the feasibility of adding 5% WFP for proper structure, texture, pasting properties, and water distribution in order to reduce fish waste.

Determine the Moisture Distribution in Sewage Sludge by Drying Differential

2014 ◽  
Vol 665 ◽  
pp. 404-407 ◽  
Author(s):  
Wan Yu ◽  
Pei Sheng Li
Keyword(s):  
Sewage Sludge ◽  
Interstitial Water ◽  
Bound Water ◽  
Free Water ◽  
High Accuracy ◽  
Moisture Distribution ◽  
Municipal Sewage ◽  
Municipal Sewage Sludge ◽  
Hot Air ◽  
Critical Water Content

Moisture distribution in sewage sludge was considered as the essential of thermal drying. Some methods were given in literatures to test the moisture distribution, but there was no standard method to determine the critical water content between different kinds of water. The municipal sewage sludge was dried by hot air in this work. Based on the drying curve, the derivative of drying rate with respect to dry basis moisture content was brought out to analyze the moisture distribution in sewage sludge. Results show that this method can easily determine the free water, interstitial water, surface water and bound water with a high accuracy. The present work can provide new insight to determine the moisture distribution in sewage sludge, which was still lacking in the literatures.

scholarly journals A thermodynamic formulation of root water uptake

2016 ◽  
Vol 20 (8) ◽  
pp. 3441-3454 ◽  
Author(s):  
Anke Hildebrandt ◽  
Axel Kleidon ◽  
Marcel Bechmann
Keyword(s):  
Soil Water ◽  
Water Uptake ◽  
Water Distribution ◽  
Bound Water ◽  
Root Water Uptake ◽  
Flow Path ◽  
Thermodynamic Evaluation ◽  
Entire Flow ◽  
Soil Water Distribution

Abstract. By extracting bound water from the soil and lifting it to the canopy, root systems of vegetation perform work. Here we describe how root water uptake can be evaluated thermodynamically and demonstrate that this evaluation provides additional insights into the factors that impede root water uptake. We derive an expression that relates the energy export at the base of the root system to a sum of terms that reflect all fluxes and storage changes along the flow path in thermodynamic terms. We illustrate this thermodynamic formulation using an idealized setup of scenarios with a simple model. In these scenarios, we demonstrate why heterogeneity in soil water distribution and rooting properties affect the impediment of water flow even though the mean soil water content and rooting properties are the same across the scenarios. The effects of heterogeneity can clearly be identified in the thermodynamics of the system in terms of differences in dissipative losses and hydraulic energy, resulting in an earlier start of water limitation in the drying cycle. We conclude that this thermodynamic evaluation of root water uptake conveniently provides insights into the impediments of different processes along the entire flow path, which goes beyond resistances and also accounts for the role of heterogeneity in soil water distribution.

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