Academic literature on the topic 'Turn permeability'
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Journal articles on the topic "Turn permeability"
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Fujita, Shogo, and Hajime Igarashi. "Homogenization of multi-turn coil with elliptic cross-section using complex permeability." COMPEL - The international journal for computation and mathematics in electrical and electronic engineering 38, no. 3 (May 7, 2019): 999–1008. http://dx.doi.org/10.1108/compel-09-2018-0356.
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Purpose The tensor complex permeability of a multi-turn coil with elliptic cross-section is analytically expressed. In field analysis, a multi-turn coil can be modeled by the uniform material that has the present tensor complex permeability. It is shown that the frequency characteristic of the present tensor complex permeability is in good agreement with that evaluated by finite element method applied to a unit cell of the multi-turn coil region. Design/methodology/approach The authors introduce a new method to evaluate the complex permeability of a multi-turn rectangular coil. To obtain the complex permeability of a rectangular coil in a closed form, it is approximated as an elliptic coil. Because the rectangular coil has different complex permeabilities in the vertical and horizontal directions, the complex permeability have to be defined in a tensor form. It suffices to discretize the coil region into rather coarse finite elements without considering the skin depth in contrast to the conventional finite element method. Findings The proposed method is shown to give the impedance of multi-turn coils which is in good agreement with results obtained by the conventional finite element (FE) analysis. By extending the proposed approach, the authors can easily perform 3D FE analysis without difficulty in discretization of the coil region with fairly fine finite elements. Moreover, they found that the approximation of rectangular coils as the elliptic coils is valid for analysis of quasi-static fields using this homogenization method. Originality/value The novelty of this study is in the approximation of the rectangular coils with elliptic coils, and the complex permeability for them is formulated here in a closed form. The proposed formula includes that for the round coils. Using the present method, the authors analyze the rectangular coils without fine discretization.
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Xu, Rou-Di, Kensuke Watanabe, and Atsushi Komatsuzaki. "Permeability for Horseradish Peroxidase in Strial Capillaries in Each Turn of Cochlea." ORL 56, no. 4 (1994): 183–89. http://dx.doi.org/10.1159/000276653.
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Maksimova, O. V. "Erythrocyte membrane permeability in diabetic patients." Kazan medical journal 69, no. 4 (August 15, 1988): 295. http://dx.doi.org/10.17816/kazmj99686.
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The state of cellular homeostasis in diabetic patients was assessed by the permeability of erythrocyte membranes, which can serve as an indicator of functional disorders of the vascular wall. It was found that the value of cytoplasmic membrane permeability depends largely on the variations in the ratio of cholesterol and phospholipids. An absolute or relative increase in membrane cholesterol content is accompanied by stabilization of cellular structures, which, in turn, leads to a decrease in permeability to non-electrolytes and ions and changes in the activity of membrane-bound enzymes.
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Kuwahara, Michio, and A. S. Verkman. "Pre-steady-state analysis of the turn-on and turn-off of water permeability in the kidney collecting tubule." Journal of Membrane Biology 110, no. 1 (August 1989): 57–65. http://dx.doi.org/10.1007/bf01870993.
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Sugita, Kazuya, Noriyuki Takata, and Etsuo Yonemochi. "Non-Effective Improvement of Absorption for Some Nanoparticle Formulations Explained by Permeability under Non-Sink Conditions." Pharmaceutics 14, no. 4 (April 7, 2022): 816. http://dx.doi.org/10.3390/pharmaceutics14040816.
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We evaluated the in vitro permeability of nanoparticle formulations of high and low lipophilic compounds under non-sink conditions, wherein compounds are not completely dissolved. The permeability of the highly lipophilic compound, griseofulvin, was improved by about 30% due to nanonization under non-sink conditions. Moreover, this permeability was about 50% higher than that under sink conditions. On the other hand, for the low lipophilic compound, hydrocortisone, there was no difference in permeability between micro-and nano-sized compounds under non-sink conditions. The nanonization of highly lipophilic compounds improves the permeability of the unstirred water layer (UWL), which in turn improves overall permeability. On the other hand, because the rate-limiting step in permeation for the low lipophilic compounds is the diffusion of the compounds in the membrane, the improvement of UWL permeability by nanonization does not improve the overall permeability. Based on this mechanism, nanoparticle formulations are not effective for low lipophilic compounds. To accurately predict the absorption of nanoparticle formulations, it is necessary to consider their permeability under non-sink conditions which reflect in vivo conditions.
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Che Norazman, Che Wan, Ramadhansyah Putra Jaya, and Meor Othman Hamzah. "Properties of Porous Asphalt Mixture Made with Styrene Butadiene Styrene under Long Term Oven Ageing." Advanced Materials Research 486 (March 2012): 378–83. http://dx.doi.org/10.4028/www.scientific.net/amr.486.378.
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Oven ageing is a set of procedure to simulate the accelerated effects of ageing on pavements structures. In this study, the effect of long-term oven ageing on porous asphalt mixture made with SBS modified binder was investigated. The resilient modulus, water permeability and air voids test results were the performance indicators used to evaluate the effects of ageing. The test results showed that, the resilient modulus of long term aged specimens was higher than those of unaged specimens. From the permeability test results, unaged SBS mixes exhibit lower coefficient permeability compared to the corresponding long-term oven age specimens. Most likely, ageing caused binder hardening, making the mix more difficult to compact and hence exhibited more continuous voids which in turn lead to higher permeability. In addition, the coefficient of permeability decreases as the binder content increased.
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Feng, Naichao, Shiqing Cheng, Weixing Lan, Guoquan Mu, Yao Peng, and Haiyang Yu. "Variable-Permeability Well-Testing Models and Pressure Response in Low-Permeability Reservoirs with non-Darcy Flow." Earth Sciences Research Journal 20, no. 1 (April 30, 2016): 1–6. http://dx.doi.org/10.15446/esrj.v20n1.54144.
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<p>This paper proposes the concept of variable-permeability effect and sets up the one-dimensional and two-dimensional non-Darcy well testing models. The finite difference algorithm is employed to solve the differential equations of the variable-permeability model, and the non-convergence of the numerical solutions is solved by using the geometric mean of permeability. The type curves of pressure and pressure derivative with variable-permeability effect are obtained, and sensitivity analysis is conducted. The results show that the type curves upturn in the middle and late sections, and the curves turn more upward with the severer of the variable-permeability effect. The severer the non-Darcy effect is, the less obviously the curve upturns caused by boundary effect. Furthermore, the boundary effect is increased by increasing the number of impermeable boundaries or decreasing the distance between the well and boundary.</p>
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Denda, Mitsuhiro, Toru Tsuchiya, Peter M. Elias, and Kenneth R. Feingold. "Stress alters cutaneous permeability barrier homeostasis." American Journal of Physiology-Regulatory, Integrative and Comparative Physiology 278, no. 2 (February 1, 2000): R367—R372. http://dx.doi.org/10.1152/ajpregu.2000.278.2.r367.
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Recent studies have shown that psychological stress can influence cutaneous barrier function, suggesting that this form of stress could trigger or aggravate skin disease. In the present study, we demonstrate that transfer of hairless mice to a different cage delays barrier recovery rates. Pretreatment with a phenothiazine sedative, chlorpromazine, before transfer of animals restored the kinetics of barrier recovery toward normal, suggesting that psychological stress is the basis for this alteration in barrier homeostasis. To determine the mechanism linking psychological stress to altered barrier recovery, we first demonstrated that plasma corticosterone levels increase markedly after transfer of animals to new cages and that pretreatment with chlorpromazine blocks this increase. Second, we demonstrated that the systemic administration of corticosterone delays barrier recovery. Finally, we demonstrated that pretreatment with the glucocorticoid receptor antagonist RU-486 blocks the delay in barrier recovery produced by systemic corticosterone, change of cage, or immobilization. These results suggest that psychological stress stimulates increased production of glucocorticoids, which, in turn, adversely affects permeability barrier homeostasis.
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Li, Guangquan, Yifang Miao, and Ruoyu Li. "Ultrasonic S-Wave to Obtain Shear Modulus and Matrix Permeability of D’Euville Limestone." Geofluids 2022 (May 6, 2022): 1–9. http://dx.doi.org/10.1155/2022/5126760.
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In this paper, velocity and attenuation of ultrasonic S-wave in a water-saturated rock are used for calculating shear modulus and matrix permeability of the rock, via a model improved from Biot theory. The model requires two inputs, i.e., the dry velocity of S-wave and the average distance of aperture representing pores, to yield phase velocity and the quality factor as functions of frequency. By fitting the predicted velocity and quality factor against the ultrasonically measured counterparts, the dry velocity of S-wave and the average distance of aperture are ascertained, which in turn yield shear modulus and matrix permeability, respectively. The modeling results on D’Euville limestone from France show that the specimen has shear modulus of 11.35 and 11.55 GPa (under differential pressures of 3 and 5 MPa, respectively) and matrix permeability of 0.0486 Darcy (under both differential pressures). The matrix permeability appears to be approximately one half of Darcy permeability.
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Zijlstra, Freek J., Marieke E. van Meeteren, Ingrid M. Garrelds, and Maarten A. C. Meijssen. "Effect of pharmacologically induced smooth muscle activation on permeability in murine colitis." Mediators of Inflammation 12, no. 1 (2003): 21–27. http://dx.doi.org/10.1080/0962935031000096944.
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Background:Both intestinal permeability and contractility are altered in inflammatory bowel disease. Little is known about their mutual relation. Therefore, anin vitroorgan bath technique was developed to investigate the simultaneous effects of inflammation on permeability and smooth muscle contractility in different segments of the colon.Methods and materials:BALB/c mice were exposed to a 10% dextran sulphate sodium drinking water solution for 7 days to induce a mild colitis, while control mice received normal tap water. Intestinal segments were placed in an oxygenated organ bath containing Krebs buffer. Permeability was measured by the transport of the marker molecules3H-mannitol and14C-polyethyleneglycol 4000. Contractility was measured through a pressure sensor. Smooth muscle relaxation was obtained by salbutamol and l-phenylephrine, whereas contraction was achieved by carbachol and 1-(3-chlorophenyl)-biguanide.Results:The intensity of mucosal inflammation increased throughout the colon. Also, regional differences were observed in intestinal permeability. In both normal and inflamed distal colon segments, permeability was diminished compared with proximal colon segments and the non-inflamed ileum. Permeability in inflamed distal colon segments was significantly decreased compared with normal distal segments. Pharmacologically induced relaxation of smooth muscles did not affect this diminished permeability, although an increased motility positively affected permeability in inflamed and non-inflamed distal colon.Conclusions:Inflammation and permeability is inversely related. The use of pro-kinetics could counteract this disturbed permeability and, in turn, could regulate the disturbed production of inflammatory mediators.
Books on the topic "Turn permeability"
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Golper, Thomas A., Andrew A. Udy, and Jeffrey Lipman. Drug dosing in acute kidney injury. Edited by William G. Bennett. Oxford University Press, 2015. http://dx.doi.org/10.1093/med/9780199592548.003.0364.
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Drug dosing in acute kidney injury (AKI) is one of the broadest topics in human medicine. It requires an understanding of markedly altered and constantly changing physiology under many disease situations, the use of the drugs to treat those variety of diseases, and the concept of drug removal during blood cleansing therapies. Early in AKI kidney function may be supraphysiologic, while later in the course there may be no kidney function. As function deteriorates other metabolic pathways are altered in unpredictable ways. Furthermore, the underlying disorders that lead to AKI alter metabolic pathways. Heart failure is accompanied by vasoconstriction in the muscle, skin and splanchnic beds, while brain and cardiac blood flow proportionally increase. Third spacing occurs and lungs can become congested. As either kidney or liver function deteriorates, there may be increased or decreased drug sensitivity at the receptor level. Acidosis accompanies several failing organs. Protein synthesis is qualitatively and quantitatively altered. Sepsis affects tissue permeability. All these abnormalities influence drug pharmacokinetics and dynamics. AKI is accompanied by therapeutic interventions that alter intrinsic metabolism which is in turn complicated by kidney replacement therapy (KRT). So metabolism and removal are both altered and constantly changing. Drug management in AKI is exceedingly complex and is only beginning to be understood. Thus, we approach this discussion in a physiological manner. Critically ill patients pass through phases of illness, sometimes rapidly, other times slowly. The recognition of the phases and the need to adjust medication administration strategies is crucial to improving outcomes. An early phase involving supraphysiologic kidney function may be contributory to therapeutic failures that result in the complication of later AKI and kidney function failure.
Book chapters on the topic "Turn permeability"
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Gachanja, Naomi N., David A. Dorward, Adriano G. Rossi, and Christopher D. Lucas. "Assays of Eosinophil Apoptosis and Phagocytic Uptake." In Methods in Molecular Biology, 113–32. New York, NY: Springer US, 2021. http://dx.doi.org/10.1007/978-1-0716-1095-4_10.
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AbstractEosinophil apoptosis (programmed cell death) plays an important role in several inflammatory and allergic conditions. Apoptosis triggers various mechanisms including activation of cysteine-aspartic proteases (caspases) and is characterized by morphological and biochemical changes. These include cellular condensation, nuclear fragmentation, increased mitochondrial permeability with loss of membrane potential, and exposure of phosphatidylserine on the cell membrane. A greater understanding of apoptotic mechanisms, subsequent phagocytosis (efferocytosis), and regulation of these processes is critical to understanding disease pathogenesis and development of potential novel therapeutic agents. Release of soluble factors and alterations to surface marker expression by eosinophils undergoing apoptosis aid them in signaling their presence to the immediate environment, and their subsequent recognition by phagocytic cells such as macrophages. Uptake of apoptotic cells usually suppresses inflammation by restricting proinflammatory responses and promoting anti-inflammatory and tissue repair responses. This, in turn, promotes resolution of inflammation. Defects in the apoptotic or efferocytosis mechanisms perpetuate inflammation, resulting in chronic inflammation and enhanced disease severity. This can be due to increased eosinophil life span or cell necrosis characterized by loss of cell membrane integrity and release of toxic intracellular mediators. In this chapter, we detail some of the key assays that are used to assess eosinophil apoptosis, as well as the intracellular signaling pathways involved and phagocytic clearance of these cells.
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Wilkinson, Ray, and Sarah Morris. "‘My Own Space in This World’: Stammering, Telephone Calls, and the Progressivity and Permeability of Turns-at-Talk." In Atypical Interaction, 319–44. Cham: Springer International Publishing, 2020. http://dx.doi.org/10.1007/978-3-030-28799-3_11.
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MASUTTI, LEONARDO, STEVENSON HALL, and JÁDISON DE OLIVEIRA. "PEREGRINO ROCK TYPES: AN ALTERNATIVE FOR PETROPHYSICAL PARAMETERS DISTRIBUTION." In Resumos do I Encontro Brasileiro de Petrofísica de Campos Maduros. Editora Realize, 2022. http://dx.doi.org/10.46943/i.ebpcm.2022.01.011.
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THE CREATION OF ROCK TYPES IS A PROCESS THAT MAKES IT POSSIBLE TO RELATE GEOLOGICAL FACIES AND PETROPHYSICAL PROPERTIES IN OIL RESERVOIRS. ROCK TYPES MUST ALSO CORRESPOND TO THE DYNAMIC BEHAVIOR OF ROCKS, CONTROLLED BY TEXTURAL FEATURES SUCH AS POROSITY TYPE AND PORE SPACE DISTRIBUTION (PORE THROAT). ROCK TYPES INTERPRETED FROM ELECTRICAL LOG RESPONSES ARE COMMONLY KNOWN AS ELECTRO-FACIES. FOR RESERVOIR MODELING, THE ROCK TYPES ARE DISTRIBUTED THROUGHOUT THE MODEL, GUIDING THE DISTRIBUTION OF PETROPHYSICAL PROPERTIES OF THE ROCKS PRESENT IN THE RESERVOIR. FLOW UNITS CAN BE CONSIDERED AS THE CONNECTION OF SIMILAR ROCK TYPES IN THE RESERVOIR. IN THE PEREGRINO FIELD, PETROPHYSICAL PARAMETERS SUCH AS PERMEABILITY, SATURATION AND RELATIVE PERMEABILITY ARE DISTRIBUTED BY THREE MAIN ELECTRO-FACIES. THESE THREE ELECTRO-FACIES ARE DEFINED BASICALLY BY SHALE VOLUME CUT-OFF AND TOTAL POROSITY AMOUNT. HOWEVER, DURING THE DEVELOPMENT OF THIS FIELD IT HAS BEEN POSSIBLE TO OBSERVE SOME VARIABILITY IN PRODUCTION(?) INSIDE OF THESE ELECTRO-FACIES, WHICH NEEDS TO BE ACCOUNTED FOR IN THE MODEL REPRESENTATIONS. THESE SUB-ELECTRO-FACIES OBSERVED HAVE DIFFERENT PETROPHYSICAL PROPERTIES BUT SIMILAR ELECTRICAL RESPONSE AS THE MAIN ELECTRO-FACIES INITIALLY INTERPRETED. THIS WORK PRESENTS THE ROCK TYPING METHODOLOGY IN ORDER TO SOLVE THIS ISSUE, BY CLASSIFYING THE PEREGRINO RESERVOIR ROCKS INTO FLOW UNITS. MORE THAN 400 CORE SAMPLES WITH POROSITY AND PERMEABILITY MEASUREMENTS HAD BEEN USED FOR DEFINING THE FLOW UNITS. SPECIAL CORE ANALYSES FROM MICP ALSO HAVE CORROBORATED THE RESULTS. THE FLOW UNITS WERE DISTRIBUTED IN THE GEOLOGICAL MODEL, IN TURN GUIDING THE PETROPHYSICAL PARAMETER DISTRIBUTIONS, SUCH AS PERMEABILITY AND WATER SATURATION, IMPROVING THE RESERVOIR HETEROGENEITY. CONSEQUENTLY, IT IS POSSIBLE TO ACHIEVE A STATIC MODEL MORE FAITHFUL TO THE RESERVOIR GEOLOGY AND SUBSEQUENTLY A MORE PREDICTIVE SIMULATION MODEL.
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MASUTTI, LEONARDO, STEVENSON HALL, and JÁDISON DE OLIVEIRA. "PEREGRINO ROCK TYPES: AN ALTERNATIVE FOR PETROPHYSICAL PARAMETERS DISTRIBUTION." In Resumos do I Encontro Brasileiro de Petrofísica de Campos Maduros. Editora Realize, 2022. http://dx.doi.org/10.46943/i.ebpcm.2022.01.011.
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THE CREATION OF ROCK TYPES IS A PROCESS THAT MAKES IT POSSIBLE TO RELATE GEOLOGICAL FACIES AND PETROPHYSICAL PROPERTIES IN OIL RESERVOIRS. ROCK TYPES MUST ALSO CORRESPOND TO THE DYNAMIC BEHAVIOR OF ROCKS, CONTROLLED BY TEXTURAL FEATURES SUCH AS POROSITY TYPE AND PORE SPACE DISTRIBUTION (PORE THROAT). ROCK TYPES INTERPRETED FROM ELECTRICAL LOG RESPONSES ARE COMMONLY KNOWN AS ELECTRO-FACIES. FOR RESERVOIR MODELING, THE ROCK TYPES ARE DISTRIBUTED THROUGHOUT THE MODEL, GUIDING THE DISTRIBUTION OF PETROPHYSICAL PROPERTIES OF THE ROCKS PRESENT IN THE RESERVOIR. FLOW UNITS CAN BE CONSIDERED AS THE CONNECTION OF SIMILAR ROCK TYPES IN THE RESERVOIR. IN THE PEREGRINO FIELD, PETROPHYSICAL PARAMETERS SUCH AS PERMEABILITY, SATURATION AND RELATIVE PERMEABILITY ARE DISTRIBUTED BY THREE MAIN ELECTRO-FACIES. THESE THREE ELECTRO-FACIES ARE DEFINED BASICALLY BY SHALE VOLUME CUT-OFF AND TOTAL POROSITY AMOUNT. HOWEVER, DURING THE DEVELOPMENT OF THIS FIELD IT HAS BEEN POSSIBLE TO OBSERVE SOME VARIABILITY IN PRODUCTION(?) INSIDE OF THESE ELECTRO-FACIES, WHICH NEEDS TO BE ACCOUNTED FOR IN THE MODEL REPRESENTATIONS. THESE SUB-ELECTRO-FACIES OBSERVED HAVE DIFFERENT PETROPHYSICAL PROPERTIES BUT SIMILAR ELECTRICAL RESPONSE AS THE MAIN ELECTRO-FACIES INITIALLY INTERPRETED. THIS WORK PRESENTS THE ROCK TYPING METHODOLOGY IN ORDER TO SOLVE THIS ISSUE, BY CLASSIFYING THE PEREGRINO RESERVOIR ROCKS INTO FLOW UNITS. MORE THAN 400 CORE SAMPLES WITH POROSITY AND PERMEABILITY MEASUREMENTS HAD BEEN USED FOR DEFINING THE FLOW UNITS. SPECIAL CORE ANALYSES FROM MICP ALSO HAVE CORROBORATED THE RESULTS. THE FLOW UNITS WERE DISTRIBUTED IN THE GEOLOGICAL MODEL, IN TURN GUIDING THE PETROPHYSICAL PARAMETER DISTRIBUTIONS, SUCH AS PERMEABILITY AND WATER SATURATION, IMPROVING THE RESERVOIR HETEROGENEITY. CONSEQUENTLY, IT IS POSSIBLE TO ACHIEVE A STATIC MODEL MORE FAITHFUL TO THE RESERVOIR GEOLOGY AND SUBSEQUENTLY A MORE PREDICTIVE SIMULATION MODEL.
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"permeability reducing admix(ture)." In Dictionary Geotechnical Engineering/Wörterbuch GeoTechnik, 981. Berlin, Heidelberg: Springer Berlin Heidelberg, 2014. http://dx.doi.org/10.1007/978-3-642-41714-6_160955.
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"How Collective Skill Formation Systems Adapt to a Knowledge Economy." In Collective Skill Formation in the Knowledge Economy, edited by Patrick Emmenegger and Giuliano Bonoli, 334–49. Oxford University PressOxford, 2022. http://dx.doi.org/10.1093/oso/9780192866257.003.0014.
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Abstract Collective skill formation systems remain attractive in the knowledge economy. However, these systems are heavily dependent on the capacity of actors to cooperate, which in turn depends on their ability to find win-win solutions to the challenges these systems confront. This concluding chapter discusses five main themes that help to understand how collective skill formation systems adapt to a knowledge economy. First, one constant preoccupation of employers is to keep dual training attractive for talented youths and avoid academic drift. This is clearly visible in their support for measures aiming to protect the value of VET degrees, to improve permeability of the overall education system, and to develop new hybrid forms of training that combine academic and vocational training. Second, in some countries, there are attempts to upskill collective skill formation systems. Such measures include investments in post-secondary VET or new forms of cooperation between firm-based training and higher-education institutions. Third, employers’ attachment to collective skill formation remains strong, but they increasingly experience problems in acting collectively, which fuels segmentalist tendencies. Fourth, over recent decades, states have developed a multitude of measures to make collective skill formation systems more inclusive. These measures tend to be external to the collective skill formation system and are rarely intrusive with regard to the role played by employers. Fifth, states put pressure on collective skill formation systems to make them more inclusive, which often—but not always—creates considerable frictions, especially if inclusion measures risk undermining the perceived quality of training.
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Mark, James E., Harry R. Allcock, and Robert West. "Polysiloxanes and Related Polymers." In Inorganic Polymers. Oxford University Press, 2005. http://dx.doi.org/10.1093/oso/9780195131192.003.0008.
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At the present time, polysiloxanes are unique among inorganic and semi-inorganic polymers. They have been the most studied by far, and are the most important with regard to commercial applications. Thus, it is not surprising that a large number of review articles exist describing the synthesis, properties, and applications of these materials. The Si-O backbone of this class of polymers endows it with a variety of intriguing properties. For example, the strength of this bond gives the siloxane polymers considerable thermal stability, which is very important for their use in high-temperature application (for example as heat-transfer agents and high-performance elastomers). The nature of the bonding and the chemical characteristics of typical side groups give the chains a very low surface free energy and, therefore, highly unusual and desirable surface properties. Not surprising, polysiloxanes are much used, for example, as mold-release agents, for waterproofing garments, and as biomedical materials. Some unusual structural features of the chains give rise to physical properties that are also of considerable scientific interest. For example, the substituted Si atom and the unsubstituted O atom differ greatly in size, giving the chain a very irregular cross section. This influences the way the chains pack in the bulk, amorphous state, which, in turn, gives the chains very unusual equation-of-state properties (such as compressibilities). Also, the bond angles around the O atom are much larger than those around the Si, and this makes the planar all-trans form of the chain approximate a series of closed polygons. As a result, siloxane chains exhibit a number of interesting configurational characteristics. These structural features, and a number of properties and their associated applications, will be discussed in this chapter. The major categories of homopolymers and copolymers to be discussed are linear siloxane polymers [-SiRR'O-] (with various alkyl and aryl R,R' side groups), (ii) sesquisiloxane polymers possibly having a ladder structure, (iii) siloxane-silarylene polymers [-Si(CH3)2OSi(CH3)2(C6H4)m-] (where the skeletal phenylene units are either meta or para), (iv) silalkylene polymers [-Si(CH3)2(CH2)m-], and (v) random and block copolymers, and blends of some of the above. Topics of particular importance are the structure, flexibility, transition temperatures, permeability, and other physical properties.
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Newnham, Robert E. "Magnetic phenomena." In Properties of Materials. Oxford University Press, 2004. http://dx.doi.org/10.1093/oso/9780198520757.003.0016.
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In this chapter we deal with a number of magnetic properties and their directional dependence: pyromagnetism, magnetic susceptibility, magnetoelectricity, and piezomagnetism. In the course of dealing with these properties, two new ideas are introduced: magnetic symmetry and axial tensors. Moving electric charge generates magnetic fields and magnetization. Macroscopically, an electric current i flowing in a coil of n turns per meter produces a magnetic field H = ni amperes/meter [A/m]. On the atomic scale, magnetization arises from unpaired electron spins and unbalanced electronic orbital motion. The weber [Wb] is the basic unit of magnetic charge m. The force between two magnetic charges m1 and m2 is where r is the separation distance and μ0 (=4π×10−7 H/m) is the permeability of vacuum. In a magnetic field H, magnetic charge experiences a force F = mH [N]. North and south poles (magnetic charges) separated by a distance r create magnetic dipole moments mr [Wb m]. Magnetic dipole moments provide a convenient way of picturing the atomistic origins arising from moving electric charge. Magnetization (I) is the magnetic dipole moment per unit volume and is expressed in units of Wb m/m3 = Wb/m2. The magnetic flux density (B = I + μ0H) is also in Wb/m2 and is analogous to the electric displacement D. All materials respond to magnetic fields, producing a magnetization I = χH, and a magnetic flux density B = μH where χ is the magnetic susceptibility and μ is the magnetic permeability. Both χ and μ are in henries/m (H/m). The permeability μ = χ + μ0 and is analogous to electric permittivity. χ and μ are sometimes expressed as dimensionless quantities (x ̅ and μ ̅ and ) like the dielectric constant, where = x ̅/μ0 and = μ ̅/μ0. Other magnetic properties will be defined later in the chapter. A schematic view of the submicroscopic origins of magnetic phenomena is presented in Fig. 14.1. Most materials are diamagnetic with only a weak magnetic response induced by an applied magnetic field.
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Knoll, Gillian. "‘A Petty World of Myself’: Intimacy and Erotic Distance in Endymion." In Conceiving Desire in Lyly and Shakespeare, 112–35. Edinburgh University Press, 2020. http://dx.doi.org/10.3366/edinburgh/9781474428521.003.0004.
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Chapter 3 analyses Lyly’s Endymion, whose eponymous hero forges an erotic connection with the moon across the vast expanse of the night sky. Endymion’s investment in Cynthia’s strangest and most distant incarnation grants him access to a form of intimacy that emerges from erotic distance. To theorize the attachment one can form with a majestic, vast, present-but-distant love object such as Cynthia, this chapter turns to Gaston Bachelard’s work on “intimate immensity,” a special mode of daydreaming in which the dreamer forms a powerful bond with an immense, mysterious, often cosmic, object of contemplation. Although such a relation requires a vast distance between the dreamer and the immense phenomenon he contemplates, Endymion’s metaphors of permeability activate a shared, mutual, and profoundly intimate erotic relation with Cynthia.
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Cave, Terence. "Live Artefacts." In Live Artefacts, 175–98. Oxford University Press, 2022. http://dx.doi.org/10.1093/oso/9780192858122.003.0010.
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In this final chapter, the notion of ‘live artefacts’ is more fully developed, initially through a detailed commentary on Alice Oswald’s imagination of Orpheus’ head floating downstream. It discusses the relationship between individual and ‘swarm’ as embodied in literary practices, then turns to the issue of (self‑)reflection, intentionality, and agency as manifested in literary artefacts. Taking the myths of Echo and Narcissus as a point of reference, it explores the ostensive (self-declaring) modes of literature, and the ways in which they display permeability and feedback between reflective and pre-reflective cognition. A line from Shakespeare’s Twelfth Night and a speech from Romeo and Juliet, together with the television series Fleabag, afford discussions of different kinds of internalized self-reflection and scepticism. The chapter closes with a review of the proposal that the literary artefact is a life-form, and with a recapitulation of key points.
Conference papers on the topic "Turn permeability"
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Desiato, Caterina. "The Conditions of Permeability: How Shared Cyberworlds Turn into Laboratories of Possible Worlds." In 2009 International Conference on CyberWorlds. IEEE, 2009. http://dx.doi.org/10.1109/cw.2009.55.
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Yao, Hai, and Weiyong Gu. "New Insight Into Deformation-Dependent Hydraulic Permeability of Hydrogels and Cartilage." In ASME 2002 International Mechanical Engineering Congress and Exposition. ASMEDC, 2002. http://dx.doi.org/10.1115/imece2002-32520.
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Hydrogels have numerous applications in biomedical engineering and biotechnology, such as in cellular and tissue engineering. The transient mechanical behavior of hydrogels is related to its interstitial fluid flow which is governed by hydraulic permeability. The hydraulic permeability of hydrogels and other hydrated soft tissues (e.g., cartilage and intervertebral disc) is deformation dependent [1–3]. Several empirical expressions for deformation-dependent permeability of cartilage have been proposed, in order to quantify the fluid flow within a gel or tissue under mechanical loading [1,2,4]. In this paper, we report a new approach to investigating deformation-dependent permeability of hydrogels. The objective of this study is to find a relationship between hydraulic permeability and tissue porosity (water content) for hydrogels, and in turn derive its deformation-dependent permeability. This study is important for understanding biological responses of cells to interstitial fluid flow in gels or in cartilage under mechanical loading.
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Zhao, Xiaoliang, Jiali Zhang, and Xinwei Liao. "A New Mathematical Model of Tight Formation for Productivity Transient Analysis with Additional Gas Driving." In SPE/IATMI Asia Pacific Oil & Gas Conference and Exhibition. SPE, 2021. http://dx.doi.org/10.2118/205787-ms.
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Abstract During the gas injection development of low-permeability carbonate reservoirs, due to the complexity of the reservoir and the complexity of the fluid phases, the current productivity evaluation methods are no longer applicable. In this paper, considering factors such as fracture characteristics, stress sensitivity, and phase distribution, a low-permeability carbonate reservoir gas injection development productivity transient analysis model is established. The results of the study show that the larger the value of permeability damage coefficient, the stronger the curve of the production curve will bend toward the pressure axis. This is because the larger the value of permeability damage coefficient, the more severe the stress sensitivity of the formation is, which shows that rock deformation has an important impact on production. When two phases appear at the bottom of the well, the seepage resistance increases due to the two-phase flow, which in turn causes the productivity of a single well to rapidly decrease. With the decrease of bottom hole pressure, this resistance will increase significantly and the productivity of a single well will decline rapidly.
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Ramabhadra Agastya, Nandana. "A Unified Parameter to Represent Reservoir Heterogeneity." In SPE Annual Technical Conference and Exhibition. SPE, 2021. http://dx.doi.org/10.2118/208630-stu.
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Abstract We aim to find a universal method and/or parameter to quantify impact of overall heterogeneity on waterflood performance. For this purpose, we combined the Lorenz coefficient, horizontal permeability to vertical permeability ratio, and thief zone permeability to average permeability ratio, with a radar chart. The area of the radar chart serves as a single parameter to rank reservoirs according to heterogeneity, and correlates to waterflood performance. The parameters investigated are vertical and horizontal permeability. Average porosity, initial water saturation, and initial diagonal pressure ratio are kept constant. Computer based experiments are used over the course of this entire research. We conducted permeability studies that demonstrate the effects of thief zones and crossflow. After normalizing these parameters into a number between 0 and 1, we then plot them on a radar chart. A reservoir's overall degree of heterogeneity can be inferred using the radar chart area procedure discussed in this study. In general, our simulations illustrate that the larger the radar chart area, the more heterogenous the reservoir is, which in turn yields higher water cut trends and lower recovery factors. Computer simulations done during this study also show that the higher the Lorenz coefficient, the higher the probability of a thief zone to exist. Simulations done to study crossflow also show certain trends with respect to under tonguing and radar chart area.
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Wan, Shuting, Heming Li, Yonggang Li, and Fanchao Meng. "Analysis of Turbo-Generator Circulating Current Between Stator Winding Parallel-Connected Branches Under Fault Conditions." In ASME 2005 Power Conference. ASMEDC, 2005. http://dx.doi.org/10.1115/pwr2005-50046.
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Firstly analyzes the generator parameters of air-gap magnetomotive force, magnetic permeability, magnetic flux density, the stator winding parallel-connected branches electromotive force distribution, and gets voltage difference and circulating current expressions between stator winding parallel-connected branches. Secondly, through analyzing the parameters changing on normal operation and fault condition, the circulating current characteristics are given based on the expressions, which are that hasn’t the circulating current when generator operates normally, and second harmonic circulating current will increase when the rotor winding inter-turn short circuit fault has happened, and fundamental circulating current will increase when stator winding inter-turn short circuit or air-gap eccentricity fault has happened. Considering that different fault has different circulating current characteristic, the generator fault diagnosis method based on circulating current was developed. Finally practically acquires SDF-9 generator data on the fault, the results of verification show that analysis is correct.
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Gramin, Pavel, Karthik Mahadev, Prashant Haldipur, and Marney Pietrobon. "Formation Damage Due to Aqueous Phase Traps in High Permeability Reservoirs and its Impact on Production Enhancement – Experimental Study." In SPE International Conference and Exhibition on Formation Damage Control. SPE, 2022. http://dx.doi.org/10.2118/208832-ms.
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Abstract Matrix acidizing, stimulation and other aqueous or solvent based pumping treatments such as scale squeezes, sand consolidation and organic deposition removal techniques play an ever-increasing role in maximizing value of high margin, high rate Deepwater wells. Near wellbore permeability impairment due to aqueous fluids capillary trap is a well-studied phenomenon in low permeability reservoirs but has not received much attention in high permeability oil reservoirs. During the execution of some of these different pumping treatments, an apparent formation damage was observed during execution in the form of lower productivity index (PI) post-treatment. In most cases, the PI impairment did not recover after the wells were brought online. In one case, the PI impairment slowly improved over time and fully recovered after the equivalent of ~1000 PV of the oil flow back. This temporary damage, in turn, created issues in terms of treatment design and execution often blurring the cause of damage and thereby affecting chemical and diverter selection and placement design variables. A laboratory study was undertaken to understand the nature of the damage. The results obtained from laboratory experiments to understand the impact of brines on effective permeability to oil are presented in this work. The results of the study are outlined below: Pore throat size distribution and degree of heterogeneity are principal factors controlling initial, short-term damage. Effective permeability reduction is related to non-uniform displacement by an alternate phase (oil or water), leaving less connected pores unswept. Long term damage depends on the flow rate / capillary number (Nc): High Rate / High Capillary Number results in short-term damage becoming permanent, Low rate / Low Capillary Number leads to gradual recovery over a long oil flowback period. Mutual solvents were not effective in removing the observed damage.
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Buijs, Hernán. "DFIT: An Interdisciplinary Validation of Fracture Closure Pressure Interpretation Across Multiple Basins." In SPE Annual Technical Conference and Exhibition. SPE, 2021. http://dx.doi.org/10.2118/206239-ms.
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Abstract Recent papers on pre-frac tests have proposed fracture closure pressure interpretation methodologies that lead to an earlier, higher stress estimation than the ones estimated from well-established practices. These early time estimations based on the fracture compliance method lead the practitioner to utilize unrealistic permeability, stress, and fracture pressure models. This, in turn, has a severe impact on the modeled fracture geometries which hinders the hydraulic fracture optimization process. A multi-basin analysis of pre-frac tests from the North Sea, Europe, Russia, North Africa and South America is presented to support traditional closure estimation techniques. The validity of traditional minimum stress interpretation techniques will be reinforced through multiple case histories by comparing permeability estimates from the time required for the fracture to achieve closure during diagnostic injections, after-closure analysis, core, pressure build up and rate transient analysis. Results will be supported further by fiber optics and production logging tool (PLT) driven flow allocation, fracture geometry assessment through micro seismic and sonic anisotropy, and diagnostic injections numerical inversions.
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Yudin, Evgeniy Viktorovich, George Aleksandrovich Piotrovskiy, Maria Vladimirovna Petrova, Alexey Petrovich Roshchektaev, and Nikita Vladislavovich Shtrobel. "New Analytical Approach to Operational Assessment of Fractured Well Productivity with Variable Permeability." In SPE Russian Petroleum Technology Conference. SPE, 2021. http://dx.doi.org/10.2118/206652-ms.
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Abstract Requirements of targeted optimization are imposed on the hydraulic fracturing operations carried out in the conditions of borderline economic efficiency of fields taking into account geological and technological features. Consequently, the development of new analytical tools foranalyzing and planning the productivity of fractured wells, taking into account the structuralfeatures of the productive reservoir and inhomogeneous distribution of the fracture conductivity, is becoming highly relevant. The paper proposes a new approach of assessing the vertical hydraulic fracture productivityin a rectangular reservoir in a pseudo-steady state, based on reservoir resistivity concept described in the papers of Meyer et al. However, there is a free parameter in the case of modeling the productivity of a hydraulic fracture by the concept. The parameter describes the distribution of the inflow along the plane of the fracture. This paper presents a systematic approach to determining of the parameter. The resulting model allows to conduct an assessment of the influence of various complications in the fracture on the productivity index. During the research a method of determining the free parameter was developed,it was based on the obtained dependence of the inflow distribution on the coordinate along the fracture of finite conductivity. The methodology allowed to refine existent analytical solution of the Meyer et al. model, which, in turn, allowed to assess the influence of different fracture damages in the hydraulic fracture on the productivity index of the well. The work includes the cases of the presence of fracture damages at the beginning and at the end of the fracture. A hydraulic fracture model was built for each of the types of damages, it was based on the developed method, and also the solution of dimensionless productivity ratio was received. The results of the obtained solution were confirmed by comparison with the numerical solutions of commercial simulators and analytical models available in the literature. The advantage of the methodology is the resulting formulas for well productivity are relatively simple, even for exotic cases ofvariable conductivity fractures. The approaches and algorithms described in the paper assume the calculation of the productivity of a hydraulic fracture with variable conductivity and the presence of other complicatingfactors.The methodology of the paper can be used for analysis and diagnosis problems with formation hydraulic fracturing. The efficiency of the calculations allows using the presented methodology to solve inverse problems of determining the efficiency of the hydraulic fracturing operation.
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Gupta, Subodh. "Issue with Stone-II Three Phase Permeability Model, and A Novel Robust Fundamentals-Based Alternative to It." In SPE Annual Technical Conference and Exhibition. SPE, 2021. http://dx.doi.org/10.2118/205883-ms.
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Abstract The objective of this paper is to present a fundamentals-based, consistent with observation, three-phase flow model that avoids the pitfalls of conventional models such as Stone-II or Baker's three-phase permeability models. While investigating the myth of residual oil saturation in SAGD with comparing model generated results against field data, Gupta et al. (2020) highlighted the difficulty in matching observed residual oil saturation in steamed reservoir with Stone-II and Baker's linear models. Though the use of Stone-II model is very popular for three-phase flow across the industry, one issue in the context of gravity drainage is how it appears to counter-intuitively limit the flow of oil when water is present near its irreducible saturation. The current work begins with describing the problem with existing combinatorial methods such as Stone-II, which in turn combine the water-oil, and gas-oil relative permeability curves to yield the oil relative permeability curve in presence of water and gas. Then starting with the fundamentals of laminar flow in capillaries and with successive analogical formulations, it develops expressions that directly yield the relative permeabilities for all three phases. In this it assumes a pore size distribution approximated by functions used earlier in the literature for deriving two-phase relative permeability curves. The outlined approach by-passes the need for having combinatorial functions such as prescribed by Stone or Baker. The model so developed is simple to use, and it avoids the unnatural phenomenon or discrepancy due to a mathematical artefact described in the context of Stone-II above. The model also explains why in the past some researchers have found relative permeability to be a function of temperature. The new model is also amenable to be determined experimentally, instead of being based on an assumed pore-size distribution. In that context it serves as a set of skeletal functions of known dependencies on various saturations, leaving constants to be determined experimentally. The novelty of the work is in development of a three-phase relative permeability model that is based on fundamentals of flow in fine channels and which explains the observed results in the context of flow in porous media better. The significance of the work includes, aside from predicting results more in line with expectations and an explanation of temperature dependent relative permeabilities of oil, a more reliable time dependent residual oleic-phase saturation in the context of gravity-based oil recovery methods.
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Md Yusof, Muhammad Aslam, Mohamad Arif Ibrahim, Muhammad Azfar Mohamed, Nur Asyraf Md Akhir, Ismail M Saaid, Muhammad Nabil Ziaudin Ahamed, Ahmad Kamal Idris, and Awangku Alizul Awangku Matali. "Predictive Modelling of CO2 Injectivity Impairment due to Salt Precipitation and Fines Migration During Sequestration." In International Petroleum Technology Conference. IPTC, 2021. http://dx.doi.org/10.2523/iptc-21483-ms.
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Abstract Recent studies indicated that reactive interactions between carbon dioxide (CO2), brine, and rock during CO2 sequestration can cause salt precipitation and fines migration. These mechanisms can severely impair the permeability of sandstone which directly affect the injectivity of supercritical CO2 (scCO2). Previous CO2 injectivity change models are ascribed by porosity change due to salt precipitation without considering the alteration contributed by the migration of particles. Therefore, this paper presents the application of response surface methodology to predict the CO2 injectivity change resulting from the combination of salt precipitation and fines migration. The impacts of independent and combined interactions between CO2, brine, and rock parameters were also evaluated by injecting scCO2 into brine saturated sandstone. The core samples were saturated with NaCl brine with salinity between 6,000 ppm to 100,000 ppm. The 0.1, 0.3, and 0.5 wt.% of different-sized hydrophilic silicon dioxide particles (0.005, 0.015, and 0.060 μm) were added to evaluate the effect of fines migration on CO2 injectivity alteration. The pressure drop profiles were recorded throughout the injection process and the CO2 injectivity alteration was represented by the ratio between the initial and final injectivity. The experimental results showed that brine salinity has a greater individual influence on permeability reduction as compared to the influence of particles (jamming ratio and particle concentration) and scCO2 injection flow rate. Moreover, the presence of both fines migration and salt precipitation during CO2 injection was also found to intensify the permeability reduction by 10%, and reaching up to threefold with increasing brine salinity and particle size. The most significant reductions in permeability were observed at higher brine salinities, as more salts are being precipitated out which, in turn, reduces the available pore spaces and leads to a higher jamming ratio. Thus, more particles were blocked and plugged especially at the slimmer pore throats. Based on comprehensive 45 core flooding experimental data, the newly developed model was able to capture a precise correlation between four input variables (brine salinity, injection flow rate, jamming ratio, and particle concentration) and CO2 injectivity changes. The relationship was also statistically validated with reported data from five case studies.