Journal articles on the topic 'Fluid flow pathways'
To see the other types of publications on this topic, follow the link: Fluid flow pathways.
Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles
Consult the top 50 journal articles for your research on the topic 'Fluid flow pathways.'
Next to every source in the list of references, there is an 'Add to bibliography' button. Press on it, and we will generate automatically the bibliographic reference to the chosen work in the citation style you need: APA, MLA, Harvard, Chicago, Vancouver, etc.
You can also download the full text of the academic publication as pdf and read online its abstract whenever available in the metadata.
Browse journal articles on a wide variety of disciplines and organise your bibliography correctly.
1
Hoffman, Monty, and James Crafton. "Multiphase flow in oil and gas reservoirs." Mountain Geologist 54, no. 1 (January 2017): 5–14. http://dx.doi.org/10.31582/rmag.mg.54.1.5.
Full textAbstract:
The porous rocks that make up oil and gas reservoirs are composed of complex combinations of pores, pore throats, and fractures. Pore networks are groups of these void spaces that are connected by pathways that have the same fluid entry pressures. Any fluid movement in pore networks will be along the pathways that require the minimum energy expenditure. After emplacement of hydrocarbons in a reservoir, fluid saturations, capillary pressure, and energy are in equilibrium, a significant amount of the reservoir energy is stored at the interface between the fluids. Any mechanism that changes the pressure, volume, chemistry, or temperature of the fluids in the reservoir results in a state of energy non-equilibrium. Existing reservoir engineering equations do not address this non-equilibrium condition, but rather assume that all reservoirs are in equilibrium. The assumption of equilibrium results in incorrect descriptions of fluid flow in energy non-equilibrium reservoirs. This, coupled with the fact that drilling-induced permeability damage is common in these reservoirs, often results in incorrect conclusions regarding the potential producibility of the well. Relative permeability damage, damage that can change which fluids are produced from a hydrocarbon reservoir, can occur even in very permeable reservoirs. Use of dependent variables in reservoir analysis does not correctly describe the physics of fluid flow in the reservoir and will lead to potentially incorrect answers regarding producibility of the reservoir.
2
Srivastava, Tarak, Hongying Dai, Daniel P. Heruth, Uri S. Alon, Robert E. Garola, Jianping Zhou, R. Scott Duncan, et al. "Mechanotransduction signaling in podocytes from fluid flow shear stress." American Journal of Physiology-Renal Physiology 314, no. 1 (January 1, 2018): F22—F34. http://dx.doi.org/10.1152/ajprenal.00325.2017.
Full textAbstract:
Recently, we and others have found that hyperfiltration-associated increase in biomechanical forces, namely, tensile stress and fluid flow shear stress (FFSS), can directly and distinctly alter podocyte structure and function. The ultrafiltrate flow over the major processes and cell body generates FFSS to podocytes. Our previous work suggests that the cyclooxygenase-2 (COX-2)-PGE2-PGE2 receptor 2 (EP2) axis plays an important role in mechanoperception of FFSS in podocytes. To address mechanotransduction of the perceived stimulus through EP2, cultured podocytes were exposed to FFSS (2 dyn/cm2) for 2 h. Total RNA from cells at the end of FFSS treatment, 2-h post-FFSS, and 24-h post-FFSS was used for whole exon array analysis. Differentially regulated genes ( P < 0.01) were analyzed using bioinformatics tools Enrichr and Ingenuity Pathway Analysis to predict pathways/molecules. Candidate pathways were validated using Western blot analysis and then further confirmed to be resulting from a direct effect of PGE2 on podocytes. Results show that FFSS-induced mechanotransduction as well as exogenous PGE2 activate the Akt-GSK3β-β-catenin (Ser552) and MAPK/ERK but not the cAMP-PKA signal transduction cascades. These pathways are reportedly associated with FFSS-induced and EP2-mediated signaling in other epithelial cells as well. The current regimen for treating hyperfiltration-mediated injury largely depends on targeting the renin-angiotensin-aldosterone system. The present study identifies specific transduction mechanisms and provides novel information on the direct effect of FFSS on podocytes. These results suggest that targeting EP2-mediated signaling pathways holds therapeutic significance for delaying progression of chronic kidney disease secondary to hyperfiltration.
3
Srivastava, Tarak, Trupti Joshi, Yuexu Jiang, Daniel P. Heruth, Mohamed H. Rezaiekhaligh, Jan Novak, Vincent S. Staggs, et al. "Upregulated proteoglycan-related signaling pathways in fluid flow shear stress-treated podocytes." American Journal of Physiology-Renal Physiology 319, no. 2 (August 1, 2020): F312—F322. http://dx.doi.org/10.1152/ajprenal.00183.2020.
Full textAbstract:
The ultrafiltrate flow over the major processes and cell body generates fluid flow shear stress (FFSS) on podocytes. Hyperfiltration-associated increase in FFSS can lead to podocyte injury and detachment. Previously, we showed that FFSS-induced upregulation of the cyclooxygenase 2 (COX2)-PGE2-prostaglandin E receptor 2 (EP2) axis in podocytes activates Akt-glycogen synthase kinase-3β-β-catenin and MAPK/ERK signaling in response to FFSS. Integrative MultiOmics Pathway Resolution (IMPRes) is a new bioinformatic tool that enables simultaneous time-series analysis of more than two groups to identify pathways and molecular connections. In the present study, we used previously characterized COX2 [prostaglandin-endoperoxide synthase 2 ( Ptgs2)], EP2 ( Ptger2), and β1-catenin ( Ctnnb1) as “seed genes” from an array data set of four groups analyzed over a time course. The 3 seed genes shared 7 pathways and 50 genes of 14 pathways and 89 genes identified by IMPRes. A composite of signaling pathways highlighted the temporal molecular connections during mechanotransduction signaling in FFSS-treated podocytes. We investigated the “proteoglycans in cancer” and “galactose metabolism” pathways predicted by IMPRes. A custom-designed PCR array validated 60.7% of the genes predicted by IMPRes analysis, including genes for the above-named pathways. Further validation using Western blot analysis showed increased expression of phosho-Erbb2, phospho-mammalian target of rapamycin (mTOR), CD44, and hexokinase II (Hk2); decreased total Erbb2, galactose mutarotase (Galm), and β-1,4-galactosyltransferase 1 (B4galt1); and unchanged total mTOR and AKT3. These findings corroborate our previously reported results. This study demonstrates the potential of the IMPRes method to identify novel pathways. Identifying the “proteoglycans in cancer” and “galactose metabolism” pathways has generated a lead to study the significance of FFSS-induced glycocalyx remodeling and possible detachment of podocytes from the glomerular matrix.
4
Reynolds, Catriona A., Hannah Menke, Matthew Andrew, Martin J. Blunt, and Samuel Krevor. "Dynamic fluid connectivity during steady-state multiphase flow in a sandstone." Proceedings of the National Academy of Sciences 114, no. 31 (July 17, 2017): 8187–92. http://dx.doi.org/10.1073/pnas.1702834114.
Full textAbstract:
The current conceptual picture of steady-state multiphase Darcy flow in porous media is that the fluid phases organize into separate flow pathways with stable interfaces. Here we demonstrate a previously unobserved type of steady-state flow behavior, which we term “dynamic connectivity,” using fast pore-scale X-ray imaging. We image the flow of N2 and brine through a permeable sandstone at subsurface reservoir conditions, and low capillary numbers, and at constant fluid saturation. At any instant, the network of pores filled with the nonwetting phase is not necessarily connected. Flow occurs along pathways that periodically reconnect, like cars controlled by traffic lights. This behavior is consistent with an energy balance, where some of the energy of the injected fluids is sporadically converted to create new interfaces.
5
Li, Ping, Chenglin Liu, Man Hu, Mian Long, Ding Zhang, and Bo Huo. "Fluid Flow-Induced Calcium Response in Osteoclasts: Signaling Pathways." Annals of Biomedical Engineering 42, no. 6 (April 8, 2014): 1250–60. http://dx.doi.org/10.1007/s10439-014-0984-x.
Full text
6
Huppert, Herbert E., Jerome A. Neufeld, and Charlotte Strandkvist. "The competition between gravity and flow focusing in two-layered porous media." Journal of Fluid Mechanics 720 (February 27, 2013): 5–14. http://dx.doi.org/10.1017/jfm.2012.623.
Full textAbstract:
AbstractThe gravitationally driven flow of a dense fluid within a two-layered porous media is examined experimentally and theoretically. We find that in systems with two horizontal layers of differing permeability a competition between gravity driven flow and flow focusing along high-permeability routes can lead to two distinct flow regimes. When the lower layer is more permeable than the upper layer, gravity acts along high-permeability pathways and the flow is enhanced in the lower layer. Alternatively, when the upper layer is more permeable than the lower layer, we find that for a sufficiently small input flux the flow is confined to the lower layer. However, above a critical flux fluid preferentially spreads horizontally within the upper layer before ultimately draining back down into the lower layer. This later regime, in which the fluid overrides the low-permeability lower layer, is important because it enhances the mixing of the two fluids. We show that the critical flux which separates these two regimes can be characterized by a simple power law. Finally, we briefly discuss the relevance of this work to the geological sequestration of carbon dioxide and other industrial and natural flows in porous media.
7
Tsuda, A., R. Kamm, and J. J. Fredberg. "Periodic flow at airway bifurcations. II. Flow partitioning." Journal of Applied Physiology 69, no. 2 (August 1, 1990): 553–61. http://dx.doi.org/10.1152/jappl.1990.69.2.553.
Full textAbstract:
The distribution of flow among parallel pathways is believed to be determined by the balance of downstream mechanical loads or time constants. We studied the influence of upstream flow conditions and airway geometry vs. downstream mechanical impedances in determining flow partitioning at airway bifurcations. Each model consisted of a single rigid bifurcation with various branching angles and area ratios but having identical pathway impedances. Sinusoidal volumetric oscillations were applied at the parent duct with various frequencies and tidal volumes. Measuring the terminal pressures continuously, we calculated the flow distribution. When flow amplitude was small, flow partitioning was homogeneous and synchronous, as expected in a system possessing homogeneous pathway impedances and time constants. But when flow amplitude was large and frequency was high, appreciable heterogeneity and asynchrony of flow partitioning arose; during midinspiration the high-velocity flow stream preferentially favored the axial pathway. This effect vanished in the absence of a net area change at the bifurcation. For a given bifurcation geometry, these observations could be organized using only two nondimensional parameters, neither of which incorporated consideration of fluid friction. The description of temporal events required, in addition, a nondimensional time. Therefore these flow-dependent phenomena and their underlying mechanisms differ fundamentally from those described in classical impedance models. The complex pattern of nonuniform interregional behaviors apparent in whole lungs when tidal volume and frequency are large (Allen et al., J. Clin. Invest. 76: 620-629, 1985) is reiterated faithfully in models consisting of only two compartments with homogeneous time constants. As such, the behaviors observed in lungs would appear to be attributable in large part to fluid dynamic factors in central airways.
8
Riddle, Ryan C., Amanda F. Taylor, Damian C. Genetos, and Henry J. Donahue. "MAP kinase and calcium signaling mediate fluid flow-induced human mesenchymal stem cell proliferation." American Journal of Physiology-Cell Physiology 290, no. 3 (March 2006): C776—C784. http://dx.doi.org/10.1152/ajpcell.00082.2005.
Full textAbstract:
Mechanical signals are important regulators of skeletal homeostasis, and strain-induced oscillatory fluid flow is a potent mechanical stimulus. Although the mechanisms by which osteoblasts and osteocytes respond to fluid flow are being elucidated, little is known about the mechanisms by which bone marrow-derived mesenchymal stem cells respond to such stimuli. Here we show that the intracellular signaling cascades activated in human mesenchymal stem cells by fluid flow are similar to those activated in osteoblastic cells. Oscillatory fluid flow inducing shear stresses of 5, 10, and 20 dyn/cm2 triggered rapid, flow rate-dependent increases in intracellular calcium that pharmacological studies suggest are inositol trisphosphate mediated. The application of fluid flow also induced the phosphorylation of extracellular signal-regulated kinase-1 and -2 as well as the activation of the calcium-sensitive protein phosphatase calcineurin in mesenchymal stem cells. Activation of these signaling pathways combined to induce a robust increase in cellular proliferation. These data suggest that mechanically induced fluid flow regulates not only osteoblastic behavior but also that of mesenchymal precursors, implying that the observed osteogenic response to mechanical loading may be mediated by alterations in the cellular behavior of multiple members of the osteoblast lineage, perhaps by a common signaling pathway.
9
Ascuitto, R. J., D. W. Kydon, and N. T. Ross-Ascuitto. "Streamlining Fluid Pathways Lessens Flow Energy Dissipation: Relevance to Atriocavopulmonary Connections." Pediatric Cardiology 24, no. 3 (May 1, 2003): 249–58. http://dx.doi.org/10.1007/s00246-002-0182-8.
Full text
10
Gunn, Iain, and Andrew W. Woods. "On the flow of buoyant fluid injected into an aquifer with a background flow." Journal of Fluid Mechanics 706 (July 12, 2012): 274–94. http://dx.doi.org/10.1017/jfm.2012.253.
Full textAbstract:
AbstractWe study the dispersal of a plume of incompressible buoyant fluid injected into a confined inclined aquifer in which there is a background flow. We assume that, to prevent pressure buildup in the system, there is an outflow from the aquifer, with flux equal to the injection flux, through a producing well. Using the method of characteristics, we identify that the trajectory of the plume of injected fluid depends on the magnitudes of both the injection flux ${Q}_{I} $ and the background aquifer flux ${Q}_{A} $ relative to the buoyancy-driven exchange flow of injected and original fluid within the aquifer ${Q}_{E} $, on the direction of the background aquifer flow, and on whether the producing well lies upslope or downslope from the injecting well. We find the values of the controlling parameters ${Q}_{I} / {Q}_{E} $ and ${Q}_{A} / {Q}_{E} $ for which all injected fluid flows up-dip, for which the injected fluid partitions into a component moving up-dip and a component moving down-dip, and for which all injected fluid flows down-dip. A key learning from the analysis is that there may be very different plume trajectories when a buoyant fluid is injected into a confined, inclined aquifer, and prediction of the trajectory depends on knowledge of the background flow as well as the injection rate and location of the producing wells. In the process of ${\mathrm{CO} }_{2} $ sequestration, this range of initial plume geometries can inform analysis of longer-term geological storage and assessment of the risk of activating different possible leakage pathways to the surface.
11
Park, Jong-Hyuk, Yong-Sook Park, Jong-Sik Suk, Seung-Won Park, Sung-Nam Hwang, Taek-Kyun Nam, Young-Baeg Kim, and Won-Bok Lee. "Cerebrospinal fluid pathways from cisterns to ventricles in N-butyl cyanoacrylate–induced hydrocephalic rats." Journal of Neurosurgery: Pediatrics 8, no. 6 (December 2011): 640–46. http://dx.doi.org/10.3171/2011.8.peds1190.
Full textAbstract:
Object Cerebrospinal fluid typically enters the subarachnoid space from the ventricles via the fourth ventricular foramina. However, there is clinical evidence that CSF also flows in the opposite direction. Ventricular reflux of CSF from a cistern is a well-known phenomenon in radioisotope studies in patients with normal-pressure hydrocephalus. Additionally, the presence of ventricular blood in acute subarachnoid hemorrhage is frequently observed. The goal of this investigation was to examine the potential CSF pathways from cisterns to ventricles. The authors examined pathways in rat models in which they occluded the fourth ventricular outlets and injected a tracer into the subarachnoid space. Methods The model for acute obstructive hydrocephalus was induced using N-butyl cyanoacrylate (NBCA) in 10 Sprague-Dawley rats. After 3 days, cationized ferritin was infused into the lumbar subarachnoid space to highlight retrograde CSF flow pathways. The animals were sacrificed at 48 hours, and the brains were prepared. The CSF flow pathway was traced by staining the ferritin with ferrocyanide. Results Ferritin was observed in the third ventricle in 7 of 8 rats with hydrocephalus and in the temporal horn of the lateral ventricles in 4 of 8 rats with hydrocephalus. There was no definite staining in the aqueduct, which suggests that the ventricular reflux originated from routes other than through the fourth ventricular outlets. Conclusions The interfaces between the quadrigeminal cistern and third ventricle and those between the ambient cistern and lateral ventricle appear to be potential sites of CSF reflux from cisterns to ventricles in obstructive hydrocephalus.
12
Brehme, Maren, Simona Regenspurg, Peter Leary, Fatih Bulut, Harald Milsch, Sigitas Petrauskas, Robertas Valickas, and Guido Blöcher. "Injection-Triggered Occlusion of Flow Pathways in Geothermal Operations." Geofluids 2018 (July 5, 2018): 1–14. http://dx.doi.org/10.1155/2018/4694829.
Full textAbstract:
Reasons for injectivity decline were investigated in a low-enthalpy geothermal aquifer in Klaipeda (Lithuania). It is one of the study sites within the DESTRESS project, which demonstrates different stimulation techniques in geothermal reservoirs. Due to low injectivity, production rates from the Lithuanian field are currently reduced, which lead to negative commercial implications for the site. Productivity from the same wells is measured to be 40 times higher. Injectivity decline in aquifers is often related to clogging processes in spatially correlated highly permeable structures, which control the main flow volume. We subdivided clogging processes into (1) physical, (2) chemical, and (3) biological processes and studied them by analyzing fluid and solid samples as well as operational data. The methods we used are fluid and solid analyses in situ, in the laboratory and in experimental setups, statistical interpretation, and numerical modeling. Our results show that the spatially correlating nature of permeable structures is responsible for exponentially decreasing injectivity because few highly permeable zones clog rapidly by intruded particles. In particular, field operations cause changes of the physical, chemical, and biological processes in the aquifer. Mineral precipitation and corrosion are the main chemical processes observed at our site. Microbial activity causes biofilm while fines migration is caused by changes in physical boundary conditions. Moreover, these processes can affect each other and generate further reactions, for example, microbial activity triggers corrosion in surface pipelines.
13
Bedussi, Beatrice, Mitra Almasian, Judith de Vos, Ed VanBavel, and Erik NTP Bakker. "Paravascular spaces at the brain surface: Low resistance pathways for cerebrospinal fluid flow." Journal of Cerebral Blood Flow & Metabolism 38, no. 4 (October 17, 2017): 719–26. http://dx.doi.org/10.1177/0271678x17737984.
Full textAbstract:
Clearance of waste products from the brain is of vital importance. Recent publications suggest a potential clearance mechanism via paravascular channels around blood vessels. Arterial pulsations might provide the driving force for paravascular flow, but its flow pattern remains poorly characterized. In addition, the relationship between paravascular flow around leptomeningeal vessels and penetrating vessels is unclear. In this study, we determined blood flow and diameter pulsations through a thinned-skull cranial window. We observed that microspheres moved preferentially in the paravascular space of arteries rather than in the adjacent subarachnoid space or around veins. Paravascular flow was pulsatile, generated by the cardiac cycle, with net antegrade flow. Confocal imaging showed microspheres distributed along leptomeningeal arteries, while their presence along penetrating arteries was limited to few vessels. These data suggest that paravascular spaces around leptomeningeal arteries form low resistance pathways on the surface of the brain that facilitate cerebrospinal fluid flow.
14
Bolton, Alistair, and Alex Maltman. "Fluid-flow pathways in actively deforming sediments: the role of pore fluid pressures and volume change." Marine and Petroleum Geology 15, no. 4 (June 1998): 281–97. http://dx.doi.org/10.1016/s0264-8172(98)00025-7.
Full text
15
Kraiss, Larry W., Andrew S. Weyrich, Neal M. Alto, Dan A. Dixon, Tina M. Ennis, Vijayanand Modur, Thomas M. McIntyre, Stephen M. Prescott, and Guy A. Zimmerman. "Fluid flow activates a regulator of translation, p70/p85 S6 kinase, in human endothelial cells." American Journal of Physiology-Heart and Circulatory Physiology 278, no. 5 (May 1, 2000): H1537—H1544. http://dx.doi.org/10.1152/ajpheart.2000.278.5.h1537.
Full textAbstract:
Cellular phenotype is determined not only by genetic transcription but also by subsequent translation of mRNA into protein. Extracellular signals trigger intracellular pathways that distinctly activate translation. The 70/85-kDa S6 kinase (pp70S6k) is a central enzyme in the signal-dependent control of translation, but its regulation in endothelial cells is largely unknown. Here we show that fluid flow (in the absence of an exogenous mitogen) as well as humoral agonists activate endothelial pp70S6k. Rapamycin, an inhibitor of the mammalian target of rapamycin (mTOR), and wortmannin, a phosphatidylinositol 3-kinase inhibitor, blocked flow-induced pp70S6kactivation; FK-506, a rapamycin analog with minimal mTOR inhibitory activity, and PD-98059, an inhibitor of the flow-sensitive mitogen-activated protein kinase pathway, had no effect. Synthesis of Bcl-3, a protein whose translation is controlled by an mTOR-dependent pathway, was induced by flow and inhibited by rapamycin and wortmannin. Transcriptional blockade did not abolish the flow-induced upregulation of Bcl-3. Fluid forces may therefore modify endothelial phenotype by specifically regulating translation of certain mRNA transcripts into protein.
16
Symss, Nigel Peter, and Shizuo Oi. "Theories of cerebrospinal fluid dynamics and hydrocephalus: historical trend." Journal of Neurosurgery: Pediatrics 11, no. 2 (February 2013): 170–77. http://dx.doi.org/10.3171/2012.3.peds0934.
Full textAbstract:
According to the CSF bulk flow theory, hydrocephalus is caused by an imbalance between CSF formation and absorption, or a block at various locations in the major CSF pathway. New theories, however, have been proposed in which minor CSF pathways may play a significant role in the development of congenital hydrocephalus. The authors review major contributions to the literature and analyze the evolution of theories of CSF dynamics in relation to hydrocephalus, dividing their development into 4 stages on the basis of historical trends. In Stage I (prior to 1950), 2 systems of classifying hydrocephalus were proposed, namely Dandy's classifications of communicating and noncommunicating hydrocephalus and Russell's nonobstructive and obstructive hydrocephalus. In Stage II (1950–1974), based on these theories of major CSF pathway dynamics, treatment focused on ventriculostomy as an alternative to reduction of CSF production by choroid plexus coagulation. In Stage III (1975–1999), some of the specific forms of hydrocephalus, especially in premature infants, were found to be unsuitable for ventriculostomy. In Stage IV (2000–2008), selection of treatment modalities evolved further, with a focus on analysis of the chronological changes in CSF dynamics and the differences in absorption pathways in the developing and mature brains. The authors focus on “minor pathway hydrocephalus” in the immature brain, differentiating it from the conventional classification of obstructive and nonobstructive “major pathway hydrocephalus.”
17
Cross, Timothy, and Yohan Kusumanegara. "Stratigraphic Controls on Petrophysical Attributes and Fluid-Flow Pathways in an Exhumed Fluvial Reservoir." Mountain Geologist 54, no. 3 (July 2017): 129–45. http://dx.doi.org/10.31582/rmag.mg.54.3.129.
Full textAbstract:
Fluvial, floodplain and lake strata of the Green River Formation (Eocene) occur within an exhumed oil reservoir exposed in a quarry near Sunnyside, Utah. Strata in the quarry highwalls define three, asymmetrical, 15- to 20-m thick, base-level-rise genetic sequences arranged in a long-term base-level-rise (landward stepping) stacking pattern. Variable intensity of oil stain on rock surfaces is a qualitative measure of pore volumes, as all permeable facies are fully saturated with oil. Visual estimates of oil-stain intensity, combined with petrophysical measurements and petrographic analysis of the different facies, were used to define fluid-flow compartments and their boundaries. Strata and facies that functioned as fluid-flow conduits, retardants and barriers were mapped on photomosaics of the quarry highwall. Three separate fluid-flow compartments coincide with the three genetic sequences. Amalgamated fluvial sandstones at the base of each genetic sequence functioned as flow units of varying permeability and degree of interconnectedness. Laterally continuous floodplain and/or lacustrine mudstones, which cap each genetic sequence, entirely lack oil in matrix porosity and functioned as fluid-flow barriers and compartment boundaries. Petrophysical properties of specific sedimentary facies are sensitive to stratigraphic position at three spatial scales, even though the sedimentary facies appear nearly identical. At the long-term scale, porosity and permeability of the same facies (trough cross-stratified sandstone is the most common) in channel sandstones of the three genetic sequences decrease in stratigraphic succession. Within each genetic sequence, porosity and permeability are highest at the base and decrease quasilinearly to the top. Using oil-stain intensity as a proxy, porosity and permeability generally decrease from base to top of each scour-based channel macroform. Petrophysical variations coincide with subtle variations in grain size and trough cross-stratification set thickness within otherwise indistinguishable sedimentary facies. These results demonstrate that conventional crossplots of porosity/permeability versus sedimentary facies are unnecessarily broad and imprecise. When such petrophysical data are plotted in a stratigraphic context, porosity and permeability values have significantly reduced scatter. Porosity and permeability measurements and predictions of each sedimentary facies should be made from a stratigraphic perspective. From our observations of variations in intensity of oil stain, homogeneity of fluid flow may not be equated directly with facies homogeneity. At one extreme of an apparent continuum, fluid-flow pathways are tortuous and extremely variable within homogeneous, high permeability, amalgamated channel sandstones. Sweep efficiencies may be low in these cases. At an intermediate position in the continuum, increased diversity of sedimentary facies and stratigraphic variability usually cause sufficient stratigraphic separation of permeable and impermeable strata such that fluid-flow pathways are more confined and have a reduced tortuosity. Sweep efficiencies may be high in these cases. At the other extreme of the continuum, where diversity of sedimentary facies and stratigraphic variability is very high, stratigraphic units are discontinuous and restricted in area. In such cases, fluid-flow pathways are not laterally connected, and sweep efficiencies would be low.
18
Zehe, Erwin, Ralf Loritz, Yaniv Edery, and Brian Berkowitz. "Preferential pathways for fluid and solutes in heterogeneous groundwater systems: self-organization, entropy, work." Hydrology and Earth System Sciences 25, no. 10 (October 5, 2021): 5337–53. http://dx.doi.org/10.5194/hess-25-5337-2021.
Full textAbstract:
Abstract. Patterns of distinct preferential pathways for fluid flow and solute transport are ubiquitous in heterogeneous, saturated and partially saturated porous media. Yet, the underlying reasons for their emergence, and their characterization and quantification, remain enigmatic. Here we analyze simulations of steady-state fluid flow and solute transport in two-dimensional, heterogeneous saturated porous media with a relatively short correlation length. We demonstrate that the downstream concentration of solutes in preferential pathways implies a downstream declining entropy in the transverse distribution of solute transport pathways. This reflects the associated formation and downstream steepening of a concentration gradient transversal to the main flow direction. With an increasing variance of the hydraulic conductivity field, stronger transversal concentration gradients emerge, which is reflected in an even smaller entropy of the transversal distribution of transport pathways. By defining “self-organization” through a reduction in entropy (compared to its maximum), our findings suggest that a higher variance and thus randomness of the hydraulic conductivity coincides with stronger macroscale self-organization of transport pathways. Simulations at lower driving head differences revealed an even stronger self-organization with increasing variance. While these findings appear at first sight striking, they can be explained by recognizing that emergence of spatial self-organization requires, in light of the second law of thermodynamics, that work be performed to establish transversal concentration gradients. The emergence of steeper concentration gradients requires that even more work be performed, with an even higher energy input into an open system. Consistently, we find that the energy input necessary to sustain steady-state fluid flow and tracer transport grows with the variance of the hydraulic conductivity field as well. Solute particles prefer to move through pathways of very high power in the transversal flow component, and these pathways emerge in the vicinity of bottlenecks of low hydraulic conductivity. This is because power depends on the squared spatial head gradient, which is in these simulations largest in regions of low hydraulic conductivity.
19
Zehe, Erwin, Ralf Loritz, Yaniv Edery, and Brian Berkowitz. "Preferential pathways for fluid and solutes in heterogeneous groundwater systems: self-organization, entropy, work." Hydrology and Earth System Sciences 25, no. 10 (October 5, 2021): 5337–53. http://dx.doi.org/10.5194/hess-25-5337-2021.
Full textAbstract:
Abstract. Patterns of distinct preferential pathways for fluid flow and solute transport are ubiquitous in heterogeneous, saturated and partially saturated porous media. Yet, the underlying reasons for their emergence, and their characterization and quantification, remain enigmatic. Here we analyze simulations of steady-state fluid flow and solute transport in two-dimensional, heterogeneous saturated porous media with a relatively short correlation length. We demonstrate that the downstream concentration of solutes in preferential pathways implies a downstream declining entropy in the transverse distribution of solute transport pathways. This reflects the associated formation and downstream steepening of a concentration gradient transversal to the main flow direction. With an increasing variance of the hydraulic conductivity field, stronger transversal concentration gradients emerge, which is reflected in an even smaller entropy of the transversal distribution of transport pathways. By defining “self-organization” through a reduction in entropy (compared to its maximum), our findings suggest that a higher variance and thus randomness of the hydraulic conductivity coincides with stronger macroscale self-organization of transport pathways. Simulations at lower driving head differences revealed an even stronger self-organization with increasing variance. While these findings appear at first sight striking, they can be explained by recognizing that emergence of spatial self-organization requires, in light of the second law of thermodynamics, that work be performed to establish transversal concentration gradients. The emergence of steeper concentration gradients requires that even more work be performed, with an even higher energy input into an open system. Consistently, we find that the energy input necessary to sustain steady-state fluid flow and tracer transport grows with the variance of the hydraulic conductivity field as well. Solute particles prefer to move through pathways of very high power in the transversal flow component, and these pathways emerge in the vicinity of bottlenecks of low hydraulic conductivity. This is because power depends on the squared spatial head gradient, which is in these simulations largest in regions of low hydraulic conductivity.
20
Spurin, Catherine, Tom Bultreys, Maja Rücker, Gaetano Garfi, Christian M. Schlepütz, Vladimir Novak, Steffen Berg, Martin J. Blunt, and Samuel Krevor. "The development of intermittent multiphase fluid flow pathways through a porous rock." Advances in Water Resources 150 (April 2021): 103868. http://dx.doi.org/10.1016/j.advwatres.2021.103868.
Full text
21
Bolèkve, J., A. Revil, F. Janod, J. L. Mattiuzzo, and J. ‐J Fry. "Preferential fluid flow pathways in embankment dams imaged by self‐potential tomography." Near Surface Geophysics 7, no. 5-6 (March 2009): 447–62. http://dx.doi.org/10.3997/1873-0604.2009012.
Full text
22
La Croix, Andrew D., Murray K. Gingras, Shahin E. Dashtgard, and S. George Pemberton. "Computer modeling bioturbation: The creation of porous and permeable fluid-flow pathways." AAPG Bulletin 96, no. 3 (March 2012): 545–56. http://dx.doi.org/10.1306/07141111038.
Full text
23
Ray, Lori A., and Jeffrey J. Heys. "Fluid Flow and Mass Transport in Brain Tissue." Fluids 4, no. 4 (November 26, 2019): 196. http://dx.doi.org/10.3390/fluids4040196.
Full textAbstract:
Despite its small size, the brain consumes 25% of the body’s energy, generating its own weight in potentially toxic proteins and biological debris each year. The brain is also the only organ lacking lymph vessels to assist in removal of interstitial waste. Over the past 50 years, a picture has been developing of the brain’s unique waste removal system. Experimental observations show cerebrospinal fluid, which surrounds the brain, enters the brain along discrete pathways, crosses a barrier into the spaces between brain cells, and flushes the tissue, carrying wastes to routes exiting the brain. Dysfunction of this cerebral waste clearance system has been demonstrated in Alzheimer’s disease, traumatic brain injury, diabetes, and stroke. The activity of the system is observed to increase during sleep. In addition to waste clearance, this circuit of flow may also deliver nutrients and neurotransmitters. Here, we review the relevant literature with a focus on transport processes, especially the potential role of diffusion and advective flows.
24
Wan, Zhifeng, Junsheng Luo, Xiaolu Yang, Wei Zhang, Jinqiang Liang, Lihua Zuo, and Yuefeng Sun. "The Thermal Effect of Submarine Mud Volcano Fluid and Its Influence on the Occurrence of Gas Hydrates." Journal of Marine Science and Engineering 10, no. 6 (June 19, 2022): 832. http://dx.doi.org/10.3390/jmse10060832.
Full textAbstract:
Mud volcanoes and other fluid seepage pathways usually transport sufficient gas for the formation of gas reservoirs and are beneficial to the accumulation of gas hydrate. On the other hand, the fluid thermal effects of mud volcanoes can constrain the occurrence of gas hydrates. Current field measurements indicate that fluid thermal anomalies impact the distribution of gas hydrates associated with mud volcanoes. However, due to the lack of quantitative analysis of the mud volcano fluid flow and thermal evolution, it is difficult to effectively reveal the occurrence of gas hydrates in mud volcano development areas and estimate their resource potential. This study took the Håkon Mosby Mud Volcano (HMMV) in the southwestern Barents Sea as the research object and comprehensively used seismic, well logging, drilling and heat flow survey data, combining the principles and methods of fluid dynamics and thermodynamics to study the fluid flow and heat transfer of a mud volcanic pathway. The space framework of the mud volcanic fluid temperature field thermal structure was established, the influence of the HMMV fluid thermal effect on gas hydrate occurrence was analyzed and the distribution and resource potential of gas hydrates in mud volcano development areas were revealed from the perspective of thermodynamics. This study provides a thermodynamic theoretical basis for gas hydrate accumulation research, exploration and exploitation under a fluid seepage tectonic environment.
25
Launay, Gaëtan, Stanislas Sizaret, Laurent Guillou-Frottier, Colin Fauguerolles, Rémi Champallier, and Eric Gloaguen. "Dynamic Permeability Related to Greisenization Reactions in Sn-W Ore Deposits: Quantitative Petrophysical and Experimental Evidence." Geofluids 2019 (February 27, 2019): 1–23. http://dx.doi.org/10.1155/2019/5976545.
Full textAbstract:
Massive greisens are commonly associated with Sn-W mineralization and constitute low-grade high-tonnage deposits. The formation of this type of deposit results from an intense pervasive metasomatic alteration involving a major fluid and mass transfer through a nominally impermeable parental granite. A decrease in the volume of the solid phases associated with the mineral replacement reactions may be a potential process for creating pathways to enhance fluid flow. Here, we explore the effects of the replacement reactions related to greisenization on the granite’s mineralogy and petrophysical properties (density, porosity, and permeability), as well as their potential implications for fluid flow in the case of the world-class Panasqueira W-Sn-(Cu) deposit, Portugal. Mineralogical and microtextural analyses of greisenized facies show that the total replacement of feldspars by muscovite is associated with a volume decrease of the solid phases that induces a significant porosity generation in greisen (~8.5%). Greisenization experiments coupled with permeability measurements show that the replacement of feldspars by muscovite permits new pathways at the crystal scale that significantly enhance the transient permeability. Moreover, permeability measurements performed on representative samples with different degrees of greisenization show that permeability increases progressively with the level of alteration from 10-20 m2 in least granite to 10-17 m2 in greisen. The correlation between the permeability and porosity evolutions demonstrates that the porous texture developed during replacement reactions creates new pathways that enhance significantly the permeability in greisen systems. The occurrences of mineral-bearing metals such as cassiterite in the newly formed porosity of greisen provide evidence that greisenization can be a decisive process for enhancing fluid flow and promoting transport of metals in Sn-W deposits. Finally, we present a model involving a positive feedback between greisenization and permeability, in which mineralizing fluids are able to generate their own pathways in initially impermeable granite via replacement reactions, which in turn promote further hydrothermal alteration and mass transport.
26
Bossennec, Claire, Yves Géraud, Johannes Böcker, Bernd Klug, Luca Mattioni, Lionel Bertrand, and Isabelle Moretti. "Characterisation of fluid flow conditions and paths in the Buntsandstein Gp. sandstones reservoirs, Upper Rhine Graben." BSGF - Earth Sciences Bulletin 192 (2021): 35. http://dx.doi.org/10.1051/bsgf/2021027.
Full textAbstract:
Deeply buried sandstone reservoirs are targeted in the Upper Rhine Graben (URG) for geothermal and hydrocarbon resources. These reservoirs are affected by a convective heat flow along fault zones and have a complex diagenetic and deformation history recorded in their paragenetic sequence. Here, the focus is made on siderite and barite cementation characterisation, which trace paleo geothermal circulations within the fracture network affecting the Buntsandstein Gp. sandstones. A double approach on geochemistry and fracture network features is used to characterise fluid-flow episodes in the rift basin and on its shoulders. Barite sulphur isotopic signature suggests a common source for all the locations. However, Rare Earth Elements distribution patterns, oxygen isotopic ratios, and fluid inclusion study suggest two distinct flow regimes for fluids associated with barite precipitation along the shoulders and at depth in the middle of the graben. The barite has a higher content in total REE and contains non-saline fluid inclusions on the graben shoulders, suggesting that fluid circulations within the border faults interact with sulphate rich layers and precipitate at temperature above 150 °C. In deep-seated samples from the central part of the basin, barite fluid inclusions show a wide range of salinities, suggesting a higher contribution of sedimentary brines and precipitation at lower temperatures (< 150 °C). According to their REE signature, these barite mineralisations are associated with siderite and apatite with a diagenetic source. A conceptual model for fluid circulation within the basin is built from this new dataset. Fast and deep down- and up-flows occur along the major border faults, locally leaching evaporitic horizons. A part of the infiltrated meteoric waters reaches the centre of the basin, where it then mixes with the brines in sedimentary. This new characterisation of fluid pathways in the targeted reservoir brings insights into geothermal circulation compartmentalisation at the basin scale.
27
Kim, Peter Geon, Haruko Nakano, Partha P. Das, Michael J. Chen, R. Grant Rowe, Stephanie S. Chou, Samantha J. Ross, et al. "Flow-induced protein kinase A–CREB pathway acts via BMP signaling to promote HSC emergence." Journal of Experimental Medicine 212, no. 5 (April 13, 2015): 633–48. http://dx.doi.org/10.1084/jem.20141514.
Full textAbstract:
Fluid shear stress promotes the emergence of hematopoietic stem cells (HSCs) in the aorta–gonad–mesonephros (AGM) of the developing mouse embryo. We determined that the AGM is enriched for expression of targets of protein kinase A (PKA)–cAMP response element-binding protein (CREB), a pathway activated by fluid shear stress. By analyzing CREB genomic occupancy from chromatin-immunoprecipitation sequencing (ChIP-seq) data, we identified the bone morphogenetic protein (BMP) pathway as a potential regulator of CREB. By chemical modulation of the PKA–CREB and BMP pathways in isolated AGM VE-cadherin+ cells from mid-gestation embryos, we demonstrate that PKA–CREB regulates hematopoietic engraftment and clonogenicity of hematopoietic progenitors, and is dependent on secreted BMP ligands through the type I BMP receptor. Finally, we observed blunting of this signaling axis using Ncx1-null embryos, which lack a heartbeat and intravascular flow. Collectively, we have identified a novel PKA–CREB–BMP signaling pathway downstream of shear stress that regulates HSC emergence in the AGM via the endothelial-to-hematopoietic transition.
28
Ajubi, N. E., J. Klein-Nulend, M. J. Alblas, E. H. Burger, and P. J. Nijweide. "Signal transduction pathways involved in fluid flow-induced PGE2 production by cultured osteocytes." American Journal of Physiology-Endocrinology and Metabolism 276, no. 1 (January 1, 1999): E171—E178. http://dx.doi.org/10.1152/ajpendo.1999.276.1.e171.
Full textAbstract:
To maintain its structural competence, the skeleton adapts to changes in its mechanical environment. Osteocytes are generally considered the bone mechanosensory cells that translate mechanical signals into biochemical, bone metabolism-regulating stimuli necessary for the adaptive process. Prostaglandins are an important part of this mechanobiochemical signaling. We investigated the signal transduction pathways in osteocytes through which mechanical stress generates an acute release of prostaglandin E2(PGE2). Isolated chicken osteocytes were subjected to 10 min of pulsating fluid flow (PFF; 0.7 ± 0.03 Pa at 5 Hz), and PGE2release was measured. Blockers of Ca2+ entry into the cell or Ca2+ release from internal stores markedly inhibited the PFF-induced PGE2 release, as did disruption of the actin cytoskeleton by cytochalasin B. Specific inhibitors of Ca2+-activated phospholipase C, protein kinase C, and phospholipase A2 also decreased PFF-induced PGE2 release. These results are consistent with the hypothesis that PFF raises intracellular Ca2+ by an enhanced entry through mechanosensitive ion channels in combination with Ca2+- and inositol trisphosphate (the product of phospholipase C)-induced Ca2+ release from intracellular stores. Ca2+ and protein kinase C then stimulate phospholipase A2activity, arachidonic acid production, and ultimately PGE2 release.
29
Kim, Sun Wook, Jonathan Ehrman, Mok-Ryeon Ahn, Jumpei Kondo, Andrea A. Mancheno Lopez, Yun Sik Oh, Xander H. Kim, et al. "Shear stress induces noncanonical autophagy in intestinal epithelial monolayers." Molecular Biology of the Cell 28, no. 22 (November 2017): 3043–56. http://dx.doi.org/10.1091/mbc.e17-01-0021.
Full textAbstract:
Flow of fluids through the gut, such as milk from a neonatal diet, generates a shear stress on the unilaminar epithelium lining the lumen. We report that exposure to physiological levels of fluid shear stress leads to the formation of large vacuoles, containing extracellular contents within polarizing intestinal epithelial cell monolayers. These observations lead to two questions: how can cells lacking primary cilia transduce shear stress, and what molecular pathways support the formation of vacuoles that can exceed 80% of the cell volume? We find that shear forces are sensed by actin-rich microvilli that eventually generate the apical brush border, providing evidence that these structures possess mechanosensing ability. Importantly, we identified the molecular pathway that regulates large vacuole formation downstream from mechanostimulation to involve central components of the autophagy pathway, including ATG5 and LC3, but not Beclin. Together our results establish a novel link between the actin-rich microvilli, the macroscopic transport of fluids across cells, and the noncanonical autophagy pathway in organized epithelial monolayers.
30
Hannocks, Melanie-Jane, Michelle E. Pizzo, Jula Huppert, Tushar Deshpande, N. Joan Abbott, Robert G. Thorne, and Lydia Sorokin. "Molecular characterization of perivascular drainage pathways in the murine brain." Journal of Cerebral Blood Flow & Metabolism 38, no. 4 (December 28, 2017): 669–86. http://dx.doi.org/10.1177/0271678x17749689.
Full textAbstract:
Perivascular compartments surrounding central nervous system (CNS) vessels have been proposed to serve key roles in facilitating cerebrospinal fluid flow into the brain, CNS waste transfer, and immune cell trafficking. Traditionally, these compartments were identified by electron microscopy with limited molecular characterization. Using cellular markers and knowledge on cellular sources of basement membrane laminins, we here describe molecularly distinct compartments surrounding different vessel types and provide a comprehensive characterization of the arachnoid and pial compartments and their connection to CNS vessels and perivascular pathways. We show that differential expression of plectin, E-cadherin and laminins α1, α2, and α5 distinguishes pial and arachnoid layers at the brain surface, while endothelial and smooth muscle laminins α4 and α5 and smooth muscle actin differentiate between arterioles and venules. Tracer studies reveal that interconnected perivascular compartments exist from arterioles through to veins, potentially providing a route for fluid flow as well as the transport of large and small molecules.
31
Barker, Shaun L. L., and Stephen F. Cox. "Evolution of fluid chemistry and fluid-flow pathways during folding and faulting: an example from Taemas, NSW, Australia." Geological Society, London, Special Publications 359, no. 1 (2011): 203–27. http://dx.doi.org/10.1144/sp359.12.
Full text
32
Nolan, Peter J., Hosein Foroutan, and Shane D. Ross. "Pollution Transport Patterns Obtained Through Generalized Lagrangian Coherent Structures." Atmosphere 11, no. 2 (February 6, 2020): 168. http://dx.doi.org/10.3390/atmos11020168.
Full textAbstract:
Identifying atmospheric transport pathways is important to understand the effects of pollutants on weather, climate, and human health. The atmospheric wind field is variable in space and time and contains complex patterns due to turbulent mixing. In such a highly unsteady flow field, it can be challenging to predict material transport over a finite-time interval. Particle trajectories are often used to study how pollutants evolve in the atmosphere. Nevertheless, individual trajectories are sensitive to their initial conditions. Lagrangian Coherent Structures (LCSs) have been shown to form the template of fluid parcel motion in a fluid flow. LCSs can be characterized by special material surfaces that organize the parcel motion into ordered patterns. These key material surfaces form the core of fluid deformation patterns, such as saddle points, tangles, filaments, barriers, and pathways. Traditionally, the study of LCSs has looked at coherent structures derived from integrating the wind velocity field. It has been assumed that particles in the atmosphere will generally evolve with the wind. Recent work has begun to look at the motion of chemical species, such as water vapor, within atmospheric flows. By calculating the flux associated with each species, a new effective flux-based velocity field can be obtained for each species. This work analyzes generalized species-weighted coherent structures associated with various chemical species to find their patterns and pathways in the atmosphere, providing a new tool and language for the assessment of pollutant transport and patterns.
33
Lee, Gi-hun, Stephanie A. Huang, Wen Y. Aw, Mitesh L. Rathod, Crescentia Cho, Frances S. Ligler, and William J. Polacheck. "Multilayer microfluidic platform for the study of luminal, transmural, and interstitial flow." Biofabrication 14, no. 2 (January 25, 2022): 025007. http://dx.doi.org/10.1088/1758-5090/ac48e5.
Full textAbstract:
Abstract Efficient delivery of oxygen and nutrients to tissues requires an intricate balance of blood, lymphatic, and interstitial fluid pressures (IFPs), and gradients in fluid pressure drive the flow of blood, lymph, and interstitial fluid through tissues. While specific fluid mechanical stimuli, such as wall shear stress, have been shown to modulate cellular signaling pathways along with gene and protein expression patterns, an understanding of the key signals imparted by flowing fluid and how these signals are integrated across multiple cells and cell types in native tissues is incomplete due to limitations with current assays. Here, we introduce a multi-layer microfluidic platform (MμLTI-Flow) that enables the culture of engineered blood and lymphatic microvessels and independent control of blood, lymphatic, and IFPs. Using optical microscopy methods to measure fluid velocity for applied input pressures, we demonstrate varying rates of interstitial fluid flow as a function of blood, lymphatic, and interstitial pressure, consistent with computational fluid dynamics (CFD) models. The resulting microfluidic and computational platforms will provide for analysis of key fluid mechanical parameters and cellular mechanisms that contribute to diseases in which fluid imbalances play a role in progression, including lymphedema and solid cancer.
34
Liotta, Domenico, Andrea Brogi, Giovanni Ruggieri, and Martina Zucchi. "Fossil vs. Active Geothermal Systems: A Field and Laboratory Method to Disclose the Relationships between Geothermal Fluid Flow and Geological Structures at Depth." Energies 14, no. 4 (February 10, 2021): 933. http://dx.doi.org/10.3390/en14040933.
Full textAbstract:
Comparison between fossil and analogue active geothermal systems permit to obtain key-parameters to define a conceptual model of the area under exploration. The approach is based on structural, kinematic, and fluid inclusions analyses. The fossil system is investigated to describe the distribution of the hydrothermal mineralization as witness of the fluid flow through geological structures and bodies, at depth. Structural and kinematic data (to define the preferential direction of fluid flow) are collected in structural stations and by scan lines and scan boxes on key outcrops. Distribution, length, width of fractures, and hydrothermal veins bring to evaluate permeability in the fossil system and, by analogy, in the deep roots of the active system. Fluid inclusions analysis shed light on density, viscosity, and temperature of the paleo-fluids. Data integration provides the hydraulic conductivity. In active geothermal systems, fieldwork is addressed to paleo-stress analysis with data from recent faults (<2 Ma), to compare with local focal mechanisms. By this, indications on the present fluid pathways are given. The main advantage resides in obtaining parameters normally got after drilling, thus contributing to strengthen the strategy of exploration, de-risking unsuccessful boreholes.
35
Jiang, Chuanyin, Xiaoguang Wang, Zhixue Sun, and Qinghua Lei. "The Role of In Situ Stress in Organizing Flow Pathways in Natural Fracture Networks at the Percolation Threshold." Geofluids 2019 (December 16, 2019): 1–14. http://dx.doi.org/10.1155/2019/3138972.
Full textAbstract:
We investigated the effect of in situ stresses on fluid flow in a natural fracture network. The fracture network model is based on an actual critically connected (i.e., close to the percolation threshold) fracture pattern mapped from a field outcrop. We derive stress-dependent fracture aperture fields using a hybrid finite-discrete element method. We analyze the changes of aperture distribution and fluid flow field with variations of in situ stress orientation and magnitude. Our simulations show that an isotropic stress loading tends to reduce fracture apertures and suppress fluid flow, resulting in a decrease of equivalent permeability of the fractured rock. Anisotropic stresses may cause a significant amount of sliding of fracture walls accompanied with shear-induced dilation along some preferentially oriented fractures, resulting in enhanced flow heterogeneity and channelization. When the differential stress is further elevated, fracture propagation becomes prevailing and creates some new flow paths via linking preexisting natural fractures, which attempts to increase the bulk permeability but attenuates the flow channelization. Comparing to the shear-induced dilation effect, it appears that the propagation of new cracks leads to a more prominent permeability enhancement for the natural fracture system. The results have particularly important implications for predicting the hydraulic responses of fractured rocks to in situ stress fields and may provide useful guidance for the strategy design of geofluid production from naturally fractured reservoirs.
36
Lee, Ann A., Dionne A. Graham, Sheila Dela Cruz, Anthony Ratcliffe, and William J. Karlon. "Fluid Shear Stress-Induced Alignment of Cultured Vascular Smooth Muscle Cells." Journal of Biomechanical Engineering 124, no. 1 (October 2, 2001): 37–43. http://dx.doi.org/10.1115/1.1427697.
Full textAbstract:
The study objectives were to quantify the time- and magnitude-dependence of flow-induced alignment in vascular smooth muscle cells (SMC) and to identify pathways related to the orientation process. Using an intensity gradient method, we demonstrated that SMC aligned in the direction perpendicular to applied shear stress, which contrasts with parallel alignment of endothelial cells under flow. SMC alignment varied with the magnitude of and exposure time to shear stress and is a continuous process that is dependent on calcium and cycloskeleton based mechanisms. A clear understanding and control of flow-induced SMC alignment will have implications for vascular tissue engineering.
37
Xu, Peng, Ming-Zhou Yu, Shu-Xia Qiu, and Bo-Ming Yu. "Monte Carlo simulation of a two-phase flow in an unsaturated porous media." Thermal Science 16, no. 5 (2012): 1382–85. http://dx.doi.org/10.2298/tsci1205382x.
Full textAbstract:
Relative permeability is a significant transport property which describes the simultaneous flow of immiscible fluids in porous media. A pore-scale physical model is developed for the two-phase immiscible flow in an unsaturated porous media according to the statistically fractal scaling laws of natural porous media, and a predictive calculation of two-phase relative permeability is presented by Monte Carlo simulation. The tortuosity is introduced to characterize the highly irregular and convoluted property of capillary pathways for fluid flow through a porous medium. The computed relative permeabilities are compared with empirical formulas and experimental measurements to validate the current model. The effect of fractal dimensions and saturation on the relative permeabilities is also discussed
38
Ball, Kelly K., Nancy F. Cruz, Robert E. Mrak, and Gerald A. Dienel. "Trafficking of Glucose, Lactate, and Amyloid-β from the Inferior Colliculus through Perivascular Routes." Journal of Cerebral Blood Flow & Metabolism 30, no. 1 (September 30, 2009): 162–76. http://dx.doi.org/10.1038/jcbfm.2009.206.
Full textAbstract:
Metabolic brain imaging is widely used to evaluate brain function and disease, and quantitative assays require local retention of compounds used to register changes in cellular activity. As labeled metabolites of [1- and 6-14C]glucose are rapidly released in large quantities during brain activation, this study evaluated release of metabolites and proteins through perivascular fluid flow, a pathway that carries solutes from brain to peripheral lymphatic drainage sites. Assays with [3,4-14C]glucose ruled out local oxidation of glucose-derived lactate as a major contributor of label loss. Brief infusion of [1-14C]glucose and D-[14C]lactate into the inferior colliculus of conscious rats during acoustic stimulation labeled the meninges, consistent with perivascular clearance of [14C]metabolites from interstitial fluid. Microinfusion of Evans blue albumin and amyloid-β1−40 (Aβ) caused perivascular labeling in the inferior colliculus, labeled the surrounding meninges, and Aβ-labeled-specific blood vessels in the caudate and olfactory bulb and was deposited in cervical lymph nodes. Efflux of extracellular glucose, lactate, and Aβ into perivascular fluid pathways is a normal route for clearance of material from the inferior colliculus that contributes to underestimates of brain energetics. Convergence of ‘watershed’ drainage to common pathways may facilitate perivascular amyloid plaque formation and pathway obstruction in Alzheimer's disease.
39
Weimbs, Thomas. "Polycystic kidney disease and renal injury repair: common pathways, fluid flow, and the function of polycystin-1." American Journal of Physiology-Renal Physiology 293, no. 5 (November 2007): F1423—F1432. http://dx.doi.org/10.1152/ajprenal.00275.2007.
Full textAbstract:
The root cause for most cases of autosomal-dominant polycystic kidney disease (ADPKD) is mutations in the polycystin-1 (PC1) gene. While PC1 has been implicated in a perplexing variety of protein interactions and signaling pathways, what its normal function is and why its disruption leads to the proliferation of renal epithelial cells are unknown. Recent results suggest that PC1 is involved in mechanotransduction by primary cilia measuring the degree of luminal fluid flow. PC1 has also recently been shown to regulate the mTOR and signal transducers and activators of transcription (STAT) 6 pathways. These two pathways are normally dormant in the healthy kidney but are activated in response to injury and appear to drive a proliferative repair response. This review develops the idea that a critical function of PC1 and primary cilia in the adult kidney may be to sense renal injury by detecting changes in luminal fluid flow and to trigger proliferation. Constitutive activation of these pathways in ADPKD would lead to the futile attempt to repair a nonexisting injury, resulting in cyst growth. The existence of many known cellular and molecular similarities between renal repair and ADPKD supports this model.
40
Miserocchi, G., D. Venturoli, D. Negrini, M. C. Gilardi, and R. Bellina. "Intrapleural fluid movements described by a porous flow model." Journal of Applied Physiology 73, no. 6 (December 1, 1992): 2511–16. http://dx.doi.org/10.1152/jappl.1992.73.6.2511.
Full textAbstract:
We injected technetium-labeled albumin (at a concentration similar to that of the pleural fluid) in the costal region of anesthetized dogs (n = 13) either breathing spontaneously or apneic. The decay rate of labeled activity at the injection site was studied with a gamma camera placed either in the anteroposterior (AP) or laterolateral (LL) projection. In breathing animals (respiratory frequency approximately 10 cycles/min), 10 min after the injection the activity decreased by approximately 50% on AP and approximately 20% on LL imaging; in apneic animals the corresponding decrease in activity was reduced to approximately 15 and approximately 3%, respectively. We considered label translocation from AP and LL imaging as a result of bulk flows of liquid along the costomediastinal and gravity-dependent direction, respectively. We related intrapleural flows to the hydraulic pressure gradients existing along these two directions and to the geometry of the pleural space. The pleural space was considered as a porous medium partially occupied by the mesh of microvilli protruding from mesothelial cells. Solution of the Kozeny-Carman equation for the observed flow velocities and pressure gradients yielded a mean hydraulic radius of the pathways followed by the liquid ranging from 2 to 4 microns. The hydraulic resistivity of the pleural space was estimated at approximately 8.5 x 10(5) dyn.s.cm-4, five orders of magnitude lower than that of interstitial tissue.
41
Holford, Simon P., Nick Schofield, and Peter Reynolds. "Subsurface fluid flow focused by buried volcanoes in sedimentary basins: Evidence from 3D seismic data, Bass Basin, offshore southeastern Australia." Interpretation 5, no. 3 (August 31, 2017): SK39—SK50. http://dx.doi.org/10.1190/int-2016-0205.1.
Full textAbstract:
There is growing evidence that intrusive magmatic bodies such as sills and dikes can influence the migration of fluids in the deep subsurface. This influence is largely due to permeability contrasts with surrounding sedimentary rocks or because of interconnected open fractures within and around intrusions acting as conduits for migrating fluids. The role of buried volcanoes in influencing crossstratal fluid migration in sedimentary basins is less well-established. However, several studies have highlighted spatial linkages between extinct hydrothermal vent complexes and fluid seepage, suggesting that buried extrusive features can also influence subsurface fluid-flow pathways, potentially leading to migration of hydrocarbon fluids between the source and reservoir. We have developed 3D seismic reflection data from the Bass Basin in offshore southeastern Australia that image an early Miocene volcanic complex with exceptional clarity. This volcanic complex is now buried by [Formula: see text] of younger sediments. The largest volcano within this complex is directly overlain by a vertical feature interpreted to be a fluid escape pipe, which extends vertically for approximately 700 m across the late Miocene-Pliocene succession. We suggest that the buried volcanic complex was able to focus vertical fluid migration to the base of the pipe because its bulk permeability was higher than that of the overlying claystone sequence. The fluid escape pipe may have initiated through either (1) hydraulic fracturing following fluid expulsion from a deep, overpressured subvolcanic source region, (2) differential compaction and doming of the overlying claystones, or (3) a combination of these processes. Our results suggest a hitherto unrecognized role for buried volcanoes in influencing dynamic subsurface processes in sedimentary basins. In particular, our study highlights that buried volcanoes may facilitate cross-stratal migration of hydrocarbons from source to reservoir, or through sealing horizons.
42
Yarushina, Viktoriya M., Lawrence Hongliang Wang, David Connolly, Gábor Kocsis, Ingrid Fæstø, Stephane Polteau, and Assia Lakhlifi. "Focused fluid-flow structures potentially caused by solitary porosity waves." Geology 50, no. 2 (October 20, 2021): 179–83. http://dx.doi.org/10.1130/g49295.1.
Full textAbstract:
Abstract Gas chimneys, fluid-escape pipes, and diffused gas clouds are common geohazards above or below most petroleum reservoirs and in some CO2 storage sites. However, the processes driving the formation of such structures are poorly understood, as are the time scales associated with their growth or their role as long-term preferential fluid-migration pathways in sedimentary basins. We present results from a multidisciplinary study integrating advanced seismic processing techniques with high-resolution simulations of geological processes. Our analyses indicate that time-dependent rock (de)compaction yields ascending solitary porosity waves forming high-porosity and high-permeability vertical chimneys that will reach the surface. The size and location of chimneys depend on the reservoir topology and compaction length. Our simulation results suggest that chimneys in the studied area could have been formed and then lost their connection to the reservoir on a time scale of a few months.
43
Soeffky, Paul, Jared Peacock, Stephan Thiel, and Lars Krieger. "Crustal fluid pathways imaged using magnetotellurics - implications for the South Australian heat flow anomaly." ASEG Extended Abstracts 2013, no. 1 (December 2013): 1–3. http://dx.doi.org/10.1071/aseg2013ab137.
Full text
44
Badertscher, N. P. "Fluid flow pathways along the Glarus overthrust derived from stable and Sr-isotope patterns." American Journal of Science 302, no. 6 (June 1, 2002): 517–47. http://dx.doi.org/10.2475/ajs.302.6.517.
Full text
45
Qin, Yi-Xian, and Minyi Hu. "Mechanotransduction in Musculoskeletal Tissue Regeneration: Effects of Fluid Flow, Loading, and Cellular-Molecular Pathways." BioMed Research International 2014 (2014): 1–12. http://dx.doi.org/10.1155/2014/863421.
Full textAbstract:
While mechanotransductive signal is proven essential for tissue regeneration, it is critical to determine specific cellular responses to such mechanical signals and the underlying mechanism. Dynamic fluid flow induced by mechanical loading has been shown to have the potential to regulate bone adaptation and mitigate bone loss. Mechanotransduction pathways are of great interests in elucidating how mechanical signals produce such observed effects, including reduced bone loss, increased bone formation, and osteogenic cell differentiation. The objective of this review is to develop a molecular understanding of the mechanotransduction processes in tissue regeneration, which may provide new insights into bone physiology. We discussed the potential for mechanical loading to induce dynamic bone fluid flow, regulation of bone adaptation, and optimization of stimulation parameters in various loading regimens. The potential for mechanical loading to regulate microcirculation is also discussed. Particularly, attention is allotted to the potential cellular and molecular pathways in response to loading, including osteocytes associated with Wnt signaling, elevation of marrow stem cells, and suppression of adipotic cells, as well as the roles of LRP5 and microRNA. These data and discussions highlight the complex yet highly coordinated process of mechanotransduction in bone tissue regeneration.
46
Pang, Xiongqi, Ian Lerche, Haiyan Zhou, and Zhengxue Jiang. "Hydrocarbon Accumulation Control by Predominant Migration Pathways." Energy Exploration & Exploitation 21, no. 3 (June 2003): 167–86. http://dx.doi.org/10.1260/014459803769520034.
Full textAbstract:
Geological analysis and physical analogy experiments indicate that, under geological conditions, hydrocarbon tends to migrate along a path of least resistance and attempt to follow the largest buoyancy component. There are four generalized modes of possible transport. First, hydrocarbons tends to migrate along the pathways with high porosity and permeability, and with a large grade difference relative to surrounding rocks (grade difference predominance); second, hydrocarbons tends to migrate in the opposite direction in overlying formations to the nadir of the sedimentation centre (divided syncline predominance); third, hydrocarbons tends to migrate in the direction of lower fluid pressure (fluid pressure predominance); fourth, hydrocarbons tends to migrate in the direction vertical to buoyancy (flow direction predominance). This paper reports on field observations in the Daqing oilfield area of China and also on physical analog experiments used to illuminate the four basic modes of transport. Under geological conditions, the hydrocarbon migration pathways are controlled by these four basic modes, which can be used to predict the directions of hydrocarbons migration and select favourable exploration locations.
47
Rustenhoven, Justin, Catherine Tanumihardja, and Jonathan Kipnis. "Cerebrovascular Anomalies: Perspectives From Immunology and Cerebrospinal Fluid Flow." Circulation Research 129, no. 1 (June 25, 2021): 174–94. http://dx.doi.org/10.1161/circresaha.121.318173.
Full textAbstract:
Appropriate vascular function is essential for the maintenance of central nervous system homeostasis and is achieved through virtue of the blood-brain barrier; a specialized structure consisting of endothelial, mural, and astrocytic interactions. While appropriate blood-brain barrier function is typically achieved, the central nervous system vasculature is not infallible and cerebrovascular anomalies, a collective terminology for diverse vascular lesions, are present in meningeal and cerebral vasculature supplying and draining the brain. These conditions, including aneurysmal formation and rupture, arteriovenous malformations, dural arteriovenous fistulas, and cerebral cavernous malformations, and their associated neurological sequelae, are typically managed with neurosurgical or pharmacological approaches. However, increasing evidence implicates interacting roles for inflammatory responses and disrupted central nervous system fluid flow with respect to vascular perturbations. Here, we discuss cerebrovascular anomalies from an immunologic angle and fluid flow perspective. We describe immune contributions, both common and distinct, to the formation and progression of diverse cerebrovascular anomalies. Next, we summarize how cerebrovascular anomalies precipitate diverse neurological sequelae, including seizures, hydrocephalus, and cognitive effects and possible contributions through the recently identified lymphatic and glymphatic systems. Finally, we speculate on and provide testable hypotheses for novel nonsurgical therapeutic approaches for alleviating neurological impairments arising from cerebrovascular anomalies, with a particular emphasis on the normalization of fluid flow and alleviation of inflammation through manipulations of the lymphatic and glymphatic central nervous system clearance pathways.
48
Ding, Jihui, Anthony C. Clark, Tiziana Vanorio, Adam D. Jew, and John R. Bargar. "Acoustic velocity and permeability of acidized and propped fractures in shale." GEOPHYSICS 87, no. 1 (November 11, 2021): MR13—MR24. http://dx.doi.org/10.1190/geo2020-0873.1.
Full textAbstract:
From geochemical reactions to proppant emplacement, hydraulic fracturing induces various chemomechanical fracture alterations in shale reservoirs. Hydraulic fracturing through the injection of a vast amount and variety of fluids and proppants has substantial impacts on fluid flow and hydrocarbon production. There is a strong need to improve our understanding on how fracture alterations affect flow pathways within the stimulated rock volume and develop monitoring tools. We have conducted time-lapse rock-physics experiments on clay-rich (carbonate-poor) Marcellus shales to characterize the acoustic velocity and permeability responses to fracture acidizing and propping. Acoustic P- and S-wave velocities and fracture permeability were measured before and after laboratory-induced fracture alterations along with microstructural imaging through X-ray computed tomography and scanning electron microscopy. Our experiments indicate that the S-wave velocity is an important geophysical observable, particularly the S-wave polarized perpendicular to fractures because it is sensitive to fracture stiffness. The acidizing and propping of a fracture decrease its elastic stiffness. This effect is stronger for acidizing, so it is possible that proppant monitoring will be masked by chemical alteration except when propping is highly efficient (i.e., most fractures are propped). However, fracture permeability is undermined by the softening of fracture surfaces due to acidizing, while being greatly enhanced by propping. These contrasting effects on fluid flow in combination with similar seismic attributes indicate the importance of experiments to improve existing rock-physics models, which must include changes to the rock frame. Such improvements are necessary for a correct interpretation of seismic velocity monitoring of flow pathways in stimulated shales.
49
Zhu, Qingzhong, Yanhui Yang, Xueying Zhang, Sanshuai Wang, Jinzhao Yang, and Jiyuan Zhang. "Pore-Scale Simulation of Gas and Water Two-Phase Flow in Rough-Walled Fractures Using the Volume of Fluid Method." Energies 15, no. 24 (December 11, 2022): 9382. http://dx.doi.org/10.3390/en15249382.
Full textAbstract:
The gas and water flow behavior in rough-walled hydrophilic fractures at the pore scale is crucial for understanding the gas production characteristics of naturally fractured formations. This paper presents a systematic analysis of the gas and water flow characteristics in both the single-fracture and Y-shaped junction fracture models using the volume of fluid (VOF) method. Numerical simulations showed that the gas/water rate ratio is the most significant factor influencing gas bubble/slug geometry, phase distribution, and saturation. The effect of fracture roughness and tortuosity is less significant than the gas/water ratio, whereas the total fluid rate has a negligible effect. For Y-shaped junction models, the phase distribution and referential pathways are predominantly controlled only by the channel aperture ratio, whereas the effect of the intersecting angle and fluid flow rate can be neglected.
50
Lang, Susan Q., Marvin D. Lilley, Tamara Baumberger, Gretchen L. Früh-Green, Sharon L. Walker, William J. Brazelton, Deborah S. Kelley, Mitchell Elend, David A. Butterfield, and Aaron J. Mau. "Extensive decentralized hydrogen export from the Atlantis Massif." Geology 49, no. 7 (April 5, 2021): 851–56. http://dx.doi.org/10.1130/g48322.1.
Full textAbstract:
Abstract Hydrogen is an important energy source for subsurface microbial communities, but its availability beyond the flow focused through hydrothermal chimneys is largely unknown. We report the widespread export of H2 across the Atlantis Massif oceanic core complex (30°N, Mid-Atlantic Ridge; up to 44 nM), which is distinct from the circulation system feeding the Lost City Hydrothermal Field (LCHF) on the massif's southern wall. Methane (CH4) abundances are generally low to undetectable (<3 nM) in fluids that are not derived from the LCHF. Reducing fluids exit the seafloor over a wide geographical area and depth range, including the summit of the massif and along steep areas of mass wasting east of the field. The depth of the fluids in the water column and their H2/CH4 ratios indicate that some are sourced separately from the LCHF. We argue that extensive H2 export is the natural consequence of fluid flow pathways strongly influenced by tectonic features and the volume and density changes that occur when ultramafic rocks react to form serpentinites, producing H2 as a by-product. Furthermore, the circulation of H2-rich fluids through uplifted mantle rocks at moderate temperatures provides geographically expansive and stable environmental conditions for the early evolution of biochemical pathways. These results provide insight into the spatial extent of H2- and CH4-bearing fluids associated with serpentinization, independent of the focused flow emanating from the LCHF.