Academic literature on the topic 'Effective electrical conductivity'
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Journal articles on the topic "Effective electrical conductivity"
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Yu, Jun Suh, B. S. Lee, Sung Churl Choi, Ji Hun Oh, and Jae Chun Lee. "Preparation and Characterization of Porous Si-Coated SiC Fiber Media." Materials Science Forum 449-452 (March 2004): 233–36. http://dx.doi.org/10.4028/www.scientific.net/msf.449-452.233.
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Electrically conductive porous Si/SiC fiber media were prepared by infiltration of liquid silicon into porous carbon fiber preforms. The series rule of mixture for the effective electrical conductivity was applied to the disc shaped samples to estimate their silicon content, effective electrical conductivity and porosity. The electrical conductivity was estimated by assuming the disc sample as a plate of equivalent geometry, i.e., same thickness, electrode distance and volume. As the volumetric content of silicon in a sample increases from 0.026% to 0.97%, the estimated electrical conductivity increases from 0.17 S/cm to 2.09 S/cm. The porosity of the samples measured by Archimedes principle was in the range of 75~83% and 1~4% less than the one estimated by the series rule of mixture for the effective electrical conductivity.
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Akhmedov, T., S. M. Otazhonov, M. M. Khalilov, N. Yunusov, U. Mamadzhanov, and N. M. Zhuraev. "Effective dielectric permeability and electrical conductivity of polycrystalline PbTe films with disturbed stochiometry." Journal of Physics: Conference Series 2131, no. 5 (2021): 052008. http://dx.doi.org/10.1088/1742-6596/2131/5/052008.
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Abstract This paper presents the study of the effective dielectric constant and electrical conductivity of polycrystalline PbTe films with disturbed stoichiometry. It is shown that superstoichiometric additions of Te and Pb within the limits of solubility by doping with PbTe contribute to a change in a wide range of concentrations of electrically active impurities and, consequently, to an increase in the dielectric constant (ɛ), electrical conductivity (σ) and absorption coefficient (α), in addition, the excess of these components strongly affects the amount of polarization.
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Li, Guoan, and Andrew S. Douglas. "The effective electrical conductivity of nonlinear laminate composites." Quarterly of Applied Mathematics 53, no. 3 (1995): 433–64. http://dx.doi.org/10.1090/qam/1343461.
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Carrington, M. E. "QED Electrical Conductivity from the 3PI Effective Action." Nuclear Physics A 820, no. 1-4 (2009): 135c—138c. http://dx.doi.org/10.1016/j.nuclphysa.2009.01.034.
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Kulakov, Vladimir, Andrey Aniskevich, Sergey Ivanov, Triinu Poltimae, and Olesja Starkova. "Effective electrical conductivity of carbon nanotube–epoxy nanocomposites." Journal of Composite Materials 51, no. 21 (2016): 2979–88. http://dx.doi.org/10.1177/0021998316678304.
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Pari, Arvind, Johan Tiemen Padding, and Remco Hartkamp. "Numerical Measurement of the Effective Electrical Conductivity of Electrolyte-Gas Bubble Dispersions." ECS Meeting Abstracts MA2023-01, no. 36 (2023): 1968. http://dx.doi.org/10.1149/ma2023-01361968mtgabs.
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Bubble formation during water electrolysis is inevitable. Apart from mass and heat transfer limitations, the presence of these bubbles causes a decrease in the local electrical conductivity of the electrolyte, thereby contributing further to the ohmic resistance of the system. Experimental and theoretical studies have shown that the effective electrical conductivity of an electrolyte-gas bubble dispersion depends on the volume fraction of gas bubbles. However, these studies do not provide insight into the dependence of conductivity on the geometric and spatial parameters of the dispersion, such as the size distribution of the bubbles or their spatial arrangement. Experimentally, the conductivity of such dispersions can be measured using the four-electrode conductivity measurement technique. In this talk, I will present a numerical rendition of this experimental technique to measure the conductivity of an electrolyte dispersed with gas bubbles, using the lattice Boltzmann method. The computational nature of the method lends itself well to investigating systems with different bubble size distributions and spatial configurations. The model also offers the flexibility to specify the surface charge density of the dispersed bubbles. The visualization of the ionic flux around these dispersed bubbles provides insights into the motion of ions along the paths of least resistance, and therefore a better understanding of the behavior of such systems. The effective conductivity of bubble dispersions with varying degrees of randomness in their spatial arrangement has been measured, ranging from a regularly packed array of bubbles to a completely random packing. We observed that the numerically measured conductivity deviates from that predicted theoretically at high bubble volume fractions. Moreover, for the same bubble volume fraction, different spatial arrangements yield different values of conductivity, thus highlighting the influence of spatial arrangement of the bubbles on the effective conductivity of the dispersion. Additionally, the spread (standard deviation) of the numerically measured conductivity about the mean value for a given bubble volume fraction is observed to be larger at moderate volume fractions, in comparison to very dilute and densely packed dispersions. This can be explained by the fact that at moderate bubble volume fractions, there is a larger probability for the formation of random bubble clusters that hinder the movement of ions. Such clusters are unlikely in dilute cases and are universal in the dense limit, and as a consequence, less variation in the resulting effective conductivity is observed for the two limiting cases. This furthermore indicates the importance of spatial arrangement on the effective conductivity of such dispersions.
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Tane, Masakazu, Soong Keun Hyun, and Hideo Nakajima. "Extended Effective-Mean-Field Analysis for Electrical Conductivity of Lotus-Type Porous Nickel." Materials Science Forum 512 (April 2006): 331–36. http://dx.doi.org/10.4028/www.scientific.net/msf.512.331.
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We studied the effective electrical conductivity of lotus-type porous nickel with cylindrical elongated pores by applying the extended effective-mean-field (extended EMF) theory that is based on Hatta-Taya’s theory and Bruggeman’s effective-medium approximation. We modeled lotus-type porous nickel as the composite materials with ellipsoidal void inclusion, and examined the effect of shape and orientation of the pores and applied-electric-field direction on the effective electrical conductivity. The extended EMF theory revealed that well-known Archie’s power law is quite useful for expressing the porosity dependence of the electrical conductivity of lotus-type porous metals even though the deviation of porous morphology exists.
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Torquato, S. "Effective electrical conductivity of two‐phase disordered composite media." Journal of Applied Physics 58, no. 10 (1985): 3790–97. http://dx.doi.org/10.1063/1.335593.
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Chechetkin, V. R. "Effective electrical and thermal conductivity of multifilament twisted superconductors." Physics Letters A 377, no. 15 (2013): 1139–42. http://dx.doi.org/10.1016/j.physleta.2013.02.034.
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Gao, Lei, Xiaofeng Zhou, and Yulong Ding. "Effective thermal and electrical conductivity of carbon nanotube composites." Chemical Physics Letters 434, no. 4-6 (2007): 297–300. http://dx.doi.org/10.1016/j.cplett.2006.12.036.
Full textDissertations / Theses on the topic "Effective electrical conductivity"
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Watkins, Bobby Gene II. "Materials selection and evaluation of Cu-W particulate composites for extreme electrical contacts." Diss., Georgia Institute of Technology, 2011. http://hdl.handle.net/1853/39494.
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Materials for extreme electrical contacts need to have high electrical conductivity coupled with good structural properties. Potential applications include motor contacts, high power switches, and the components of electromagnetic launch (EML) systems. In particular, the lack of durability of these materials in rail components limits practical EML implementation. These rails experience significant amounts of Joule heating, due to extreme current densities, and subsequent thermally-assisted wear. New more durable materials solutions are needed for these components. A systematic materials selection study was executed to identify and compare candidate materials solutions. Several possible candidate non-dominated materials as well as hybrid materials that could potential fill the "white spaces" on the Ashby charts were identified. A couple potential candidate materials were obtained and evaluated. These included copper-tungsten W-Cu, "self-lubricating" graphite-impregnated Cu, and Gr-W-Cu composites with different volume fractions of the constituents. The structure-property relations were determined through mechanical and electrical resistivity testing. A unique test protocol for exposing mechanical test specimens to extreme current densities up to 1.2 GA/m2 was developed and used to evaluate these candidate materials. The systematic design of multi-functional materials for these extreme electrical contacts requires more than an empirical approach. Without a good understanding of both the tribological and structural performance, the optimization of the microstructure will not be quickly realized. By using micromechanics modeling and other materials design modeling tools coupled with systematic mechanical and tribological experiments, the design of materials for these applications can potentially be accelerated. In addition, using these tools, more complex functionally-graded materials tailored to the application can be systematically designed. In this study, physics- and micromechanics-based models were used to correlate properties to the volume fraction of the constituents of the evaluated candidate materials. Properties correlated included density, elastic modulus, hardness, strength, and electrical resistivity of the W-Cu materials.
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Mada, Mykanth Reddy Materials Science & Engineering Faculty of Science UNSW. "Fabrication and characterisation of SWCNT-PMMA and charcoal-PMMA composites with superior electrical conductivity and surface hardness properties." Awarded by:University of New South Wales. Materials Science & Engineering, 2009. http://handle.unsw.edu.au/1959.4/41831.
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Fabrication of SWCNT-PMMA and Activated Charcoal- PMMA composites was carried out by the compression moulding technique. Then Mechanical and Electrical properties of the composites were investigated. The morphological studies of composites showed a) good dispersion of fillers and b) good interaction between fillers and matrix. Electrical conductivity of SWCNT-PMMA composites was increased by 9 orders of magnitude (at 0.8 % volume fraction of SWCNT) and that of AC-PMMA composites increased by 16 orders of magnitude (at 17 % volume fraction of AC). The percolation threshold of both composites turned out to be lower compared to the theoretical values. A significant improvement in mechanical properties was obtained ??? particularly in AC-PMMA composites which showed a 400 % improvement in Vickers microhardness ??? raising the polymer matrix abrasion property literally to that of Aluminium alloys (Dobrazanski et al 2006). In conclusion, it is to be noted that Activated Charcoal - PMMA composites have a great potential for cost effective conducting polymer composite production by the use of cheap filler: In addition, the compression moulding technique shows good potential for cost effective fabricating technique for amorphous polymers with high electrical and mechanical properties.
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Seidel, Gary Don. "Micromechanics modeling of the multifunctional nature of carbon nanotube-polymer nanocomposites." [College Station, Tex. : Texas A&M University, 2007. http://hdl.handle.net/1969.1/ETD-TAMU-1881.
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Wood, Sandra Jean. "Determination of effective thermal conductivity of media surrounding underground transmission cables." Thesis, Georgia Institute of Technology, 1993. http://hdl.handle.net/1853/17390.
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Kader, Ammar. "Caractérisation et modélisation électromagnétique de multimatériaux composites : application aux structures automobiles." Thesis, Bordeaux, 2015. http://www.theses.fr/2015BORD0056.
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Ce manuscrit se focalise sur l’effet de divers matériaux composites sur les différentes problématiques de compatibilité électromagnétique dans un véhicule automobile. Les modèles surfaciques des matériaux diélectriques sont validés en confrontant des résultats de mesures et de simulation de leurs permittivités. Ceux des matériaux conducteurs le sont en confrontant le modèle d’impédance de surface à un modèle filaire et en effectuant des mesures des simulations de paramètres S sur une structure majoritairement constituée par un matériau de ce type. Dans les deux cas, la technique de modélisation donne de bons résultats. L’évaluation de l’effet de ces matériaux sur les problématiques de CEM au niveau d’un véhicule est faite sur un démonstrateur qui intègre les équipements et les faisceaux embarqués dans un véhicule en les représentants par des monopôles et des fils conducteurs. L’évaluation des effets des différents matériaux composites sur les problématiques CEM est faite par mesure et simulation des couplages électromagnétiques à l’intérieur du démonstrateur et entre le démonstrateur et une antenne test. L’analyse des couplages électromagnétiques confirme que le modèle d’impédance de surface reproduit assez bien les comportements des matériaux composites étudiés. Concernant l’effet des matériaux composites sur les problématiques CEM au niveau d’un véhicule, cette étude mène à deux résultats majeurs du point de vue de la compatibilité électromagnétique. Le premier concerne l’usage des matériaux diélectriques qui augmente globalement la plupart des couplages mesurés de 5 dB à 30 dB. Le second porte sur le matériau conducteur étudié qui n’a quasiment aucun effet sur les différents couplages analysés en comparaison de la structure en acier<br>The main concern of this thesis is the characterization of the impacts of some composite materials on the main electromagnetic compatibility issues in a vehicle. The surface models of the dielectric materials are validated by confronting their simulated and measured permittivity. The surface model of the studied conductive material is validated by confronting it to a wire model and by measuring and simulating the S parameters on a structure constituted by such a material. It appears in both cases of dielectric and conductive composite materials that the surface impedance modeling technique gives a good description of the materials. The analysis of the effects of these materials on the EMC issues within a vehicle is done by use of a demonstrator representing the car body. The different equipment and harnesses embedded in a vehicle are represented in the demonstrator by some wires and monopoles. The evaluation of the impact of the composite materials on the EMC issues is done by measuring and simulating the different couplings within the demonstrator and between the demonstrator and a test antenna. The analysis of the different couplings confirms that the surface impedance material modeling approach describes well the materials under test. Concerning the impact of the composite materials on the EMC issues at a vehicle level, this analysis fulfills two main results. The first one concerns the dielectric materials. Indeed the use of these materials increases the different coupling by a value varying between at least 5 dB to 30 dB. The second conclusion concerns the use of conductive composite materials. It appears that they have no effect on the different couplings in comparison to the full steel structure
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Fang, Chen Yihui. "Modélisation thermique des moteurs asynchrones en vue de la réalisation d'un outil CAO." Rouen, 1994. http://www.theses.fr/1994ROUE5077.
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Une modélisation thermique d'un moteur asynchrone fermé est effectuée dans la présente étude à l'aide d'un logiciel de calcul en éléments finis appelé Systus. Le modèle conçu en 3D représente une configuration assez complexe du moteur. Le coefficient d'échange dans les enceintes du moteur est un paramètre non accessible comme il est reconnu dans la littérature scientifique. De ce fait, un modèle de mélange parfait de l'écoulement dans les enceintes est avancé afin d'identifier le coefficient d'échange. Ce traitement est original et efficace. Grâce à la performance du logiciel Systus, les conductivités effectives du bobinage sont déduites par voie numérique, et celles du paquet de tôles par confrontation entre l'échauffement simulé et mesuré. Dans un but de généraliser la modélisation, nous avons réalisé un outil informatique d'identification qui est constitué par un programme d'optimisation non linéaire Rosenbrock et un modèle établi sous Systus. Une procédure automatique et paramétrique de simulation en champ de températures est fournie afin de rendre l'utilisation plus facile pour les concepteurs
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Sauti, Godfrey. "Electrical conductivity and permittivity of ceramics and other composites." Thesis, 2006. http://hdl.handle.net/10539/1752.
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Student Number : 0009815Y -
PhD thesis -
School of Physics -
Faculty of Science<br>Determining the properties of composites and how these relate to those of
the components and the microstructure is extremely useful as it enables the
understanding of existing materials and the design of new materials with a
variety of applications. However, the link between the ac conductivity data
and the microstructure and composition of the composite is not a simple
one. Simulations of binary composites are presented which show that from
relatively simple component properties arise complex composite properties.
Accurate identi¯cation of the components of composites, using characteristic
frequencies, is demonstrated for simulated and actual experimental data.
The Maxwell-Wagner and Brick Layer Models, which are often applied
beyond the range of their original derivation, are found to consistently ¯t
the data of yttria-stabilized zirconia ceramics measured at various tempera-
tures. The results from ¯tting single crystal and polycrystalline sample data
indicate that accurate modeling of the properties of the polycrystalline sam-
ples requires more theoretical work on the conduction mechanisms in single
crystals and the grains of the ceramics.
Data from a polyester-resin/silicon system is found to be best ¯tted us-
ing the Single Exponent Phenomenological Percolation Equation (SEPPE)
with experimentally measured component properties as input. The percola-
tion threshold obtained suggests a system where the insulator tends coat the
conductor. The results show that, with the actual component properties as
input, the SEPPE can be used to qualitatively and semi-quantitatively model
and ¯t composite ac conductivity data.
Analysis of the ac conductivity of liquid-phase-sintered silicon carbide ce-
ramics showed that for this system, the features often observed in the imped-
ance spectra are all due to a multi-component grain bondary/binder phase
and not the SiC grains. This multi-component grain boundary phase can be
¯tted accurately to the Brick Layer Model, indicating a microstructure where
an insulating component coats a more conducting component.
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"Elliptic problems of effective conductivity of nonlinear composites." Chinese University of Hong Kong, 1994. http://library.cuhk.edu.hk/record=b5888610.
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by Chu Kin Fung.<br>Thesis (M.Phil.)--Chinese University of Hong Kong, 1994.<br>Includes bibliographical references (leaves 73-75).<br>Chapter 1 --- Introduction --- p.1<br>Chapter 2 --- Preliminaries --- p.6<br>Chapter 2.1 --- Basic Notations --- p.6<br>Chapter 2.2 --- Function Spaces --- p.8<br>Chapter 3 --- Examples of Exactly Solvable Cases --- p.19<br>Chapter 4 --- Existence and Uniqueness of Solutions --- p.29<br>Chapter 5 --- Properties of Solutions --- p.41<br>Chapter 6 --- Perturbation Expansion --- p.49
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Zayid, Aadil. "Factors Effecting the Electrical Conductivity and Zeta Potential of Alumina Nanofluids." 2014. http://hdl.handle.net/10222/50641.
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This study investigates of the effect of nanoparticle volume fractions, NaCl concentration and pH on size of agglomerates, electrical conductivity and zeta potential of alumina nanofluids. The volume fractions used were 1, 2, 3 and 5 vol%. Different base fluids were prepared by adding NaCl (100, 300 and 500 ppm) or adjusting the pH (9, 7, 5 and 3).
The results showed that the size of nanoparticle agglomerates was increased with an increase in nanoparticles concentration and NaCl concentration. Also, the electrical conductivity was increased with an increase in nanoparticle concentration and NaCl concentration.
The size of nanoparticle agglomerates was 110 nm and the electrical conductivity was 290.2 μS/cm at pH 3 and 0 ppm, which was the highest value of electrical conductivity and smallest agglomerates nanoparticle size at 1 vol% with no salt. The highest value was 1830 μS/cm at pH 9 and 500 ppm of NaCl with 5 vol% of nanoparticles.
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Li, Wei-Che, and 李瑋哲. "Electrophoretic Mobility and Effective Electric Conductivity of Suspensions of Charged Porous Spherical Shells." Thesis, 2016. http://ndltd.ncl.edu.tw/handle/y878d8.
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碩士<br>國立臺灣大學<br>化學工程學研究所<br>105<br>An analysis is presented for the electrophoresis and electric conduction in a dilute suspension of charged spherical porous shells or permeable microcapsules with electric double layers of arbitrary thickness in an electrolyte solution. With the assumption that the system is slightly perturbed from equilibrium, the linearized electrokinetic equations governing the ionic electrochemical potential energy and fluid velocity distributions are solved as series expansions in the small fixed charge density of the porous shells. Explicit formulas for the electrophoretic mobility of the porous shells and effective electric conductivity of the suspension are derived. Both the electrophoretic mobility and the effective conductivity decrease monotonically with a decrease in the relative thickness of the porous shells, but these decreases are not conspicuous until the porous shells are quite thin. When the fluid permeability of the porous shells is smaller or the electric double layers are thicker, the effect of this relative thickness on the electrophoretic mobility and effective conductivity becomes more significant. In the limiting case of zero inner radius of the porous shells, our formulas reduce to the corresponding results obtained for the electrophoresis and electric conduction in a suspension of charged porous spheres.
Books on the topic "Effective electrical conductivity"
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Center, Langley Research, ed. Effective conductivity of wire mesh reflectors for space deployable antenna systems. National Aeronautics and Space Administration, Langley Research Center, 1994.
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A, Davis William. Effective conductivity of wire mesh reflectors for space deployable antenna systems. National Aeronautics and Space Administration, Langley Research Center, 1994.
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Ammari, Habib, and Hyeonbae Kang. Polarization and Moment Tensors: With Applications to Inverse Problems and Effective Medium Theory. Springer London, Limited, 2007.
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Ammari, Habib, and Hyeonbae Kang. Polarization and Moment Tensors: With Applications to Inverse Problems and Effective Medium Theory. Springer New York, 2010.
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Polarization and Moment Tensors: With Applications to Inverse Problems and Effective Medium Theory (Applied Mathematical Sciences). Springer, 2007.
Find full textBook chapters on the topic "Effective electrical conductivity"
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Snarskii, A., and M. Zhenirovsky. "Effective Conductivity of Non-Linear Composites and Electrical Breakdown." In Continuum Models and Discrete Systems. Springer Netherlands, 2004. http://dx.doi.org/10.1007/978-1-4020-2316-3_23.
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Mutenhabundo, Winnie, Tawanda Mushiri, Timothy Gutu, and Patson Zvandasara. "Liquid Desiccant Dehumidification Systems: Jet Cross-Talking Effect in Multi-electrosprays." In Lecture Notes in Mechanical Engineering. Springer International Publishing, 2023. http://dx.doi.org/10.1007/978-3-031-28839-5_29.
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AbstractWhen liquid desiccant systems are employed to dehumidify air electrospraying technique helps to increase the surface area of the liquid. Multiplexing of the jets by introducing several emitters for increased efficiency is commendable but, there is a tendency of the jets to cross talk with each other due to electrical shielding. Cross talking of jets will result in the failure of the jets to break properly into droplets for effective dehumidification. This piece of work analyzed the conditions for electrical shielding among jets which results in efficient electrospray. To evaluate how cross talking affects multiple emitter nozzles, the mathematical model was built by superimposing the electric potentials of one emitter in an array of emitters. A Computational Fluid Dynamics simulation model was developed to investigate the conditions for electrical shielding among jets during electrospray process with glycerol as the working substance. In flow modelling, Ansys Fluent with Volume of Fluid and the Taylor Dielectric model were involved. The flow rate that guarantees stability in the electrospray was determined together with the optimum voltage resulting in a spray current which reduces electrical shielding. An analysis on the electrical conductivity of the liquid to ensure stability and efficiency in electrospray was done. The pressure contours of the nozzle were determined together with velocity of the desiccant against density. Emitter spacing, applied voltage, flow rate and the electrical conductivity plays a pivotal role on the prevention of cross talking of jets during the electrospraying process.
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Tane, Masakazu, Soong Keun Hyun, and Hideo Nakajima. "Extended Effective-Mean-Field Analysis for Electrical Conductivity of Lotus-Type Porous Nickel." In Materials Science Forum. Trans Tech Publications Ltd., 2006. http://dx.doi.org/10.4028/0-87849-996-2.331.
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Voigt, Immanuel, Axel Fickert, Hajo Wiemer, and Welf-Guntram Drossel. "Experimental Investigation of Passive Thermal Error Compensation Approach for Machine Tools." In Lecture Notes in Production Engineering. Springer International Publishing, 2023. http://dx.doi.org/10.1007/978-3-031-34486-2_19.
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AbstractConventional approaches to counteract thermal issues in machine tools often require a significant amount of electrical energy input, such as in active cooling systems. An energy-efficient way for reducing thermal errors is to use passive components that redistribute heat introduced by feed drives and other internal heat sources. On the one hand, latent heat storage units can be integrated into the machine to enhance the thermal stability within the phase transition temperature range of the underlying phase change material. By using latent heat storage units, the impact of highly time-varying heat flows on the thermal displacement of the tool center point can be reduced. On the other hand, passive heat-transfer devices such as heat pipes allow for an increased heat exchange within the machine tool or between the machine tool and the environment. Heat pipes exhibit a very high effective thermal heat conductivity and can be used to transfer heat from machine-internal heat sources to additionally integrated heat sinks. A compensation system is presented combining latent heat storage units and heat pipe systems. To evaluate the effect of the corresponding components on thermally induced displacements, experimental investigations of the system within a machine tool are conducted. By means of temperature and displacement measurements it is demonstrated that the proposed compensation approach allows for partial compensation of the thermal error of the machine tool.
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"Transformers Nanofluids." In Emerging Nanotechnology Applications in Electrical Engineering. IGI Global, 2021. http://dx.doi.org/10.4018/978-1-7998-8536-8.ch006.
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This chapter interprets the impacts of powder nanoparticles on upgrading the electrical and physical properties of pure transformer oils and contains the new technologies for preparation transformers nanofluids. This chapter draws attention to the theories of dynamic charging and effective parameters for nanofluid polarization. Furthermore, this chapter presents recent procedures for estimation and control of nanofluids conductivity and the effects of nanoparticles on nanofluid conductivity. Moreover, this chapter demonstrates the favored methodology of nanofluid preparation and the tested high voltage breakdown. The precision of recommendation and forecast is another addition to qualitative investigations.
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DiFilippo, Aaron, Amrita Chakraborty, and Marius K. Orlowski. "Towards Organic Electronics: Enhanced PEDOT:PSS Electrode Conductivity." In Organic Electronics - From Fundamentals to Applications [Working Title]. IntechOpen, 2024. http://dx.doi.org/10.5772/intechopen.1007691.
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This chapter focuses on enhancing the electrical conductivity of Poly (3,4-ethylenedioxythiophene) Polystyrene Sulfonate (PEDOT:PSS:PSS) films for flexible substrate-based organic electronics. Techniques such as acid treatments, doping with noble and non-noble metal nanoparticles (Cu and Ag), multiple layer depositions, and the incorporation of mono/multiatomic layer graphene are systematically investigated. The optimized process prioritizes PEDOT:PSS multilayer depositions and nitric acid treatment, proving more effective and cost-efficient compared to alternatives using metal nanoparticles and graphene. When exposed to nitric acid, the optimized multilayer PEDOT:PSS:PSS stack decreases sheet resistance to 7.66 Ω/sq. from over 1 MΩ/sq., which results in an extraordinary conductivity of 15,701 S/cm, as opposed to 0.17 S/cm for single PEDOT:PSS layer films. The research details adhesion techniques using oxygen plasma treatment and patterning methods involving Ag sacrificial layers. The enhanced electrical conductivity achieved through multiple PEDOT:PSS: PSS depositions does not result in a significant increase in thickness, allowing for the attainment of very high electrical conductivity values. The study also addresses film aging and strategies to mitigate reliability effects induced by ambient conditions. These findings offer significant advancements in the fabrication of organic conductive electrodes, providing engineering flexibility for various applications and ensuring long-term reliability and performance of the films.
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Prajapati, Vipul D. "Polymers in Retinal Prosthesis." In Materials Research Foundations. Materials Research Forum LLC, 2025. https://doi.org/10.21741/9781644903353-14.
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Retinal prostheses or prosthesis, types of medical devices, are commonly designed to restore vision in individuals suffering from the retinitis pigmentosa (RP) and age-relating macular degeneration (AMD) types of retinal degenerative diseases. These devices interface with the remaining retinal cells to stimulate visual perception through electrical signals. Polymers play a major role in the formation of retinal prostheses due to their needful major characteristics such as biocompatibility, flexibility, and conductivity. Conductive polymers, in particular, are used to create electrodes that can effectively transmit electrical impulses to the retinal cells. Moreover, the flexibility of polymeric materials allows for the fabrication of devices that conform to the curved surface of the retina, reducing mechanical stress and improving patient comfort. Recent advancements in polymeric science have led to the formulation of novel materials with enhanced properties, such as improved electrical conductivity and stability, which are essential for the long-term performance of retinal prostheses. This chapter highlights the potential of polymers to improve the functionality and durability of retinal prostheses, paving the way for more effective treatments for blindness.
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Rubin, Yoram. "Moments of the Flow Variables, Part II : The Effective Conductivity." In Applied Stochastic Hydrogeology. Oxford University Press, 2003. http://dx.doi.org/10.1093/oso/9780195138047.003.0010.
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Many applications require primary information such as average fluxes as a prelude to more complex calculations. In water balance calculations one may be interested only in the average fluxes. For both cases the concept of effective conductivity is useful. The effective hydraulic conductivity is defined by where the angled brackets denote the expected value operator. The local flux fluctuation is defined by the difference qi(x) — (qi(x)). Its statistical properties as well as those of the velocity will be investigated in chapter 6. To qualify as an effective property in the strict physical sense, Kef must be a function of the aquifer’s material properties and not be influenced by flow conditions such as the head gradient and boundary conditions (Landauer, 1978). Our goal in this chapter is to explore the concept of the effective conductivity Kef and to relate it to the medium’s properties under as general conditions as possible. Additionally, we shall explore the conditions where this concept is irrelevant and applicable, the important issue being that Kef is defined in an ensemble sense, but for applications we need spatial averages. Several methods for deriving Kef will be described below. The general approach for defining Kef includes the following steps. First, H is defined as an SRF and is expressed with the aid of the flow equation in terms of the hydro-geological SRFs (conductivity, mostly) and the boundary conditions. The H SRF is then substituted in Darcy’s law and an expression in the form equivalent to (5.1) is sought. If and only if the coefficient in front of the mean head gradient is not a function of the flow conditions will it qualify as Kef. The derivation of the effective conductivity employs the flow equation. In steady-state incompressible flow, for example, Laplace’s equation is employed. Solutions derived under Laplace’s equation are applicable, under appropriate conditions, for other physical phenomena governed by the same mathematical model. For example, the electrical field in steady state is also described by Laplace’s equation.
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Enoki, Toshiaki, Morinobu Endo, and Masatsugu Suzuki. "Electron Transport Properties." In Graphite Intercalation Compounds and Applications. Oxford University Press, 2003. http://dx.doi.org/10.1093/oso/9780195128277.003.0008.
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In GICs, charge transfer between graphite and intercalate produces a large concentration of charge carriers, featuring an electron or hole nature in donor or acceptor GICs, respectively, as discussed in Chapter 5. GICs are therefore metallic, in contrast with the semi-metallic properties of host graphite. The typical inplane conductivity values for GICs are in the range of ~ 105 Ω−1 cm−1, which is one order of magnitude larger than the in-plane conductivity of pristine graphite (Delhaes, 1977). It is well known that the conductivity of some GICs, such as AsF5, exceeds that of copper, suggesting the properties of synthetic metals (Vogel et al., 1977). As discussed in Chapter 5, GICs have two-dimensional (2D) features in the electronic properties inherent to their stacking structure, so that electron transport is considerably anisotropic between in-plane and interplane electron conduction processes. In the in-plane process, conduction electrons, whose concentration is estimated from eq (5.9), contribute to the coherent electron conduction, and the electrical conductivity σa or resistivity ρa is described as follows (Drude formula): . . .σa =1/ρa = Neμ= Ne2τ/(m*). . . . . .(6.1). . . where N, μ, τ, and m* are the density, mobility, relaxation time, and effective mass of the conduction carriers (electrons or holes), respectively.
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"New Generation Transparent Conducting Electrode Materials for Solar Cell Technologies." In Materials for Solar Cell Technologies I. Materials Research Forum LLC, 2021. http://dx.doi.org/10.21741/9781644901090-4.
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Transparent conducting electrodes (TCEs) play a vital role for the fabrication of solar cells and pivoted almost 50% of the total cost. Recently several materials have been identified as TCEs in solar cell applications. Still, indium tin oxide (ITO) based TCEs have dominated the market due to their outstanding optical transparency and electrical conductivity. However, inadequate availability of indium has increased the price of ITO based TCEs, which attracts the researchers to find alternative materials to make solar technology economical. In this regard, various kinds of conducting materials are available and synthesized worldwide with high electrical conductivity and optical transparency in order to find alternative to ITO based electrodes. Especially, new generation nanomaterials have opened a new window for the fabrication of cost effective TCEs. Carbon nanomaterials such as graphene, carbon nanotubes (CNTs), metal nanowires (MNWs) and metal mesh (MMs) based electrodes especially attracted the scientific community for fabrication of low cost photovoltaic devices. In addition to it, various conducting polymers such as poly (3, 4-ethylene dioxythiophene): poly (styrenesulfonate) (PEDOT:PSS) based TCEs have also showed their candidacy as an alternative to ITO based TCEs. Thus, the present chapter gives an overview on materials available for the TCEs and their possible use in the field of solar cell technology
Conference papers on the topic "Effective electrical conductivity"
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Kutishcheva, Anastasiia Yu, Sergey I. Markov, and Ekaterina I. Shtanko. "Multiscale Numerical Simulation for Assessing Effective Electrical Conductivity Estimations of Geological Medium." In 2024 IEEE 3rd International Conference on Problems of Informatics, Electronics and Radio Engineering (PIERE). IEEE, 2024. https://doi.org/10.1109/piere62470.2024.10804985.
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Clemeña, Gerardo G. "Electrically Conductive Portland Cement Concrete." In CORROSION 1987. NACE International, 1987. https://doi.org/10.5006/c1987-87122.
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Abstract There is a need for an effective, simple-to-install secondary anode system for use in the cathodic protection of reinforced concrete bridge decks. In pursuit of such a system, carbon black and carbon fibers were incorporated in portland cement concrete in an attempt to improve its electrical conductivity. It was found that, carbon fibers alone or in combination with carbon black, considerably improved the electrical conductivity without sacrificing the desirable mechanical properties of the conventional concrete. Potentially, such a concrete could be used as an overlay on a repaired deck to act as a secondary anode to effectively spread the protective current of a cathodic protective system over the entire deck, and thereby simplify the installation.
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Nambu, Koichiro, and Ryuji Kunimatsu. "Surface Modification of Copper by Resin Particle Peening Treatment." In IFHTSE 2024. ASM International, 2024. http://dx.doi.org/10.31399/asm.cp.ifhtse2024p0297.
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Abstract Copper is expected to be increasingly used in electric vehicle components because of its high electrical and thermal conductivity. On the other hand, copper has the disadvantage of low fatigue strength compared to structural members such as steel and aluminum alloys. Therefore, the peening treatment is used in this study to increase the strength of copper. However, the projectile used in conventional peening treatments is much harder than copper, which may lead to deterioration of surface properties. Therefore, we decided to use a resin particle peening treatment that uses soft resin particles. For the projectile material, we used particles made from crushed walnut, apricot, and peach, which are natural material particles. Ceramic particles were used for comparison. Hardness measurements revealed that the near-surface hardness increased even when resin particles were used. In addition, compressive residual stresses were observed on the surface. Fatigue tests revealed that the fatigue strength improvement effect was higher than that of nontreated materials or hard particles. These results indicate that the resin particle peening treatment is an effective method for strengthening copper.
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Natsi, P. D., P. G. Koutsoukos, and Z. Amjad. "Inhibition of Formation of Magnesium Hydroxide by Polymers: the Role of Molecular Architecture." In CORROSION 2021. AMPP, 2021. https://doi.org/10.5006/c2021-16710.
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Abstract In thermal desalination process by multistage flash (MSF) desalination, magnesium hydroxide (brucite) is a major component of the alkaline (or “soft”) scale formed at lower temperatures than the ‘hard” calcium sulfate scale. Brucite formation has also been reported during lime softening process. During the last three decades various additives have been developed to control precipitation of scale forming salts. This study is focused on the evaluation of synthetic poly(acrylic acids) with functional groups (carboxylic acid, -COOH) which have the potential to act as inhibitors for brucite scale. Two poly(acrylic acids) were tested with molecular weights (MW) 2,000 (PAA2k) and 6,000 (PAA6k), respectively. They were present in solutions supersaturated with respect to brucite and the spontaneous precipitation was monitored by the solutions electrical conductivity. Both polymers were effective inhibitors of the crystal growth of the supercritical nuclei forming in the solutions. The effect of the polymers as brucite inhibitors was compared with 1-hydroxyethylidine 1,1-diphosphonic acid (HEDP). The efficiency of inhibition followed the order: HEDP &gt; PAA2k &gt; PAA6k.
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Cloete, Eugene. "Electrochemically Activated Water as a Non Polluting Anti-Fouling Technology." In CORROSION 2002. NACE International, 2002. https://doi.org/10.5006/c2002-02463.
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Abstract Research has indicated the problem of microbial resistance to nonoxidising biocides. Very little information is further more available on the biodegradability of these compounds in natural water systems. This makes these compounds hazardous from an environmental point of view. Chlorine is the most widely used oxidizing biocide, with its own limitations. An environmentally sensible alternative to chlorine and other commonly used biocides is needed. Electrochemically activated water (ECA) solutions, may provide such an alternative. Water of varying mineralisation is passed through an electrochemical cell, the specific design of which, permits the harnessing of two distinct and electrically opposite streams of activated water. Aside from its distinctive attributes, the negatively charged antioxidant solution (Catholyte) can also be channeled back into the anode chamber, thereby modulating the quality of the positively charged oxidant solution (Anolyte) that is produced. Without maintenance of the activated state, these diverse products degrade to the relaxed state of benign water and the anomalous attributes of the activated solutions such as altered conductivity and surface tension similarly revert to pre-activation status. However, the heightened electrical activity and altered physico-chemical attributes of the solutions differ significantly from the benign state, but yet remain non-toxic to mammalian tissue and the environment. The anti-microbial activity of the current ECA technology has been confirmed in this study. Electrochemically activated water (ECA) is less toxic, less volatile, easier to handle, compatible with other water treatment chemicals, effective against biofilms and generates no by-products compared to currently used biocides.
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Pfeifer, Andrew R., and George Shaw. "Environmentally Friendly Fastener Finishes." In CORROSION 2002. NACE International, 2002. https://doi.org/10.5006/c2002-02163.
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Abstract “The Perfect Finish” is something that the industry has been seeking for years. It is an elusive concept for which millions of dollars have been spent in developing, testing and qualifying possible alternative finishes, but most of these efforts are futile. In order for engineers to be most effective, a realization must be made that each finish, from phosphate to cadmium, has strengths and weaknesses that must be weighed in considering each application. It is with these considerations that progress can be made toward using the materials that have the closest resemblance to the qualities of cadmium and, in turn, accepting their weaknesses. This paper describes a research study conducted on eight finishes that are potential replacements for cadmium. Information is specific to fasteners with regards to clamp load and corrosion, both cosmetic and galvanic. The scope was broadened to understand many different elements of each finish to give engineers information that is vital to recommending their usage as cadmium substitutes and exposing weaknesses of each finish. One inorganic alternative was found to be a drop-in replacement for cadmium, and another two were found to closely resemble performance of cadmium in all respects except for electrical conductivity.
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Hack, Harvey P., Richard Corbett, and Brad Krantz. "Inhibition of Heavy Metal Ion Corrosion on Aluminum in Fresh Water Cooling Systems Using Propylene Glycol Anti-Freeze." In CORROSION 1998. NACE International, 1998. https://doi.org/10.5006/c1998-98220.
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Abstract Electronics cooling and environmental control systems are required in enclosed manned spaces such as the inside of spacecraft or submersibles. Because egress from such spaces may not be possible in a short time frame, coolant leaks must have minimum toxicity. For this reason, propylene glycol coolants are preferred over the traditional ethylene glycol coolants. Corrosion inhibitor formulations are well developed for ethylene glycol coolants, but there is concern that the inhibitor suite for propylene glycol systems may not be as mature. In particular, coolant systems with a mixture of aluminum and copper can develop heavy metal ion corrosion of the aluminum due to precipitation of copper ions from solution onto the aluminum. This type of accelerated corrosion of aluminum does not require electrical contact with copper, as is the case for galvanic corrosion, nor is significant coolant conductivity required for corrosion to occur. This paper presents a study of the ability of a commercial inhibited propylene glycol coolant to prevent heavy metal ion corrosion of aluminum when copper is also present in the coolant system. The inhibited propylene glycol’s performance is compared to that of reagent propylene glycol without inhibitors, a mature ethylene glycol inhibited coolant, and to tap water. The inhibitor suite in the inhibited propylene glycol was found to be as effective in controlling heavy metal ion corrosion as that of the inhibited ethylene glycol coolant, while uninhibited reagent propylene glycol was ineffective in controlling heavy metal ion corrosion.
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Lu, Xiaoxin, Yu Liu, Lionel Pichon, Delong He, Olivier Dubrunfaut, and Jinbo Bai. "Effective electrical conductivity of CNT/polymer nanocomposites." In 2020 International Symposium on Electromagnetic Compatibility - EMC EUROPE. IEEE, 2020. http://dx.doi.org/10.1109/emceurope48519.2020.9245805.
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Frame, James, Wakana Kubo, and Xu Fang. "Plasmonic Tuning of Effective Phase Transition Temperature and Electrical Conductivity." In CLEO: Applications and Technology. OSA, 2018. http://dx.doi.org/10.1364/cleo_at.2018.jw2a.95.
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Hossain, Md Biplob, and Md Masud Rana. "An effective modified modeling of graphene interband conductivity." In 2015 International Conference on Electrical Engineering and Information Communication Technology (ICEEICT). IEEE, 2015. http://dx.doi.org/10.1109/iceeict.2015.7307358.
Full textReports on the topic "Effective electrical conductivity"
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Friedman, Shmuel, Jon Wraith, and Dani Or. Geometrical Considerations and Interfacial Processes Affecting Electromagnetic Measurement of Soil Water Content by TDR and Remote Sensing Methods. United States Department of Agriculture, 2002. http://dx.doi.org/10.32747/2002.7580679.bard.
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Time Domain Reflectometry (TDR) and other in-situ and remote sensing dielectric methods for determining the soil water content had become standard in both research and practice in the last two decades. Limitations of existing dielectric methods in some soils, and introduction of new agricultural measurement devices or approaches based on soil dielectric properties mandate improved understanding of the relationship between the measured effective permittivity (dielectric constant) and the soil water content. Mounting evidence indicates that consideration must be given not only to the volume fractions of soil constituents, as most mixing models assume, but also to soil attributes and ambient temperature in order to reduce errors in interpreting measured effective permittivities. The major objective of the present research project was to investigate the effects of the soil geometrical attributes and interfacial processes (bound water) on the effective permittivity of the soil, and to develop a theoretical frame for improved, soil-specific effective permittivity- water content calibration curves, which are based on easily attainable soil properties. After initializing the experimental investigation of the effective permittivity - water content relationship, we realized that the first step for water content determination by the Time Domain Reflectometry (TDR) method, namely, the TDR measurement of the soil effective permittivity still requires standardization and improvement, and we also made more efforts than originally planned towards this objective. The findings of the BARD project, related to these two consequential steps involved in TDR measurement of the soil water content, are expected to improve the accuracy of soil water content determination by existing in-situ and remote sensing dielectric methods and to help evaluate new water content sensors based on soil electrical properties. A more precise water content determination is expected to result in reduced irrigation levels, a matter which is beneficial first to American and Israeli farmers, and also to hydrologists and environmentalists dealing with production and assessment of contamination hazards of this progressively more precious natural resource. The improved understanding of the way the soil geometrical attributes affect its effective permittivity is expected to contribute to our understanding and predicting capability of other, related soil transport properties such as electrical and thermal conductivity, and diffusion coefficients of solutes and gas molecules. In addition, to the originally planned research activities we also investigated other related problems and made many contributions of short and longer terms benefits. These efforts include: Developing a method and a special TDR probe for using TDR systems to determine also the soil's matric potential; Developing a methodology for utilizing the thermodielectric effect, namely, the variation of the soil's effective permittivity with temperature, to evaluate its specific surface area; Developing a simple method for characterizing particle shape by measuring the repose angle of a granular material avalanching in water; Measurements and characterization of the pore scale, saturation degree - dependent anisotropy factor for electrical and hydraulic conductivities; Studying the dielectric properties of cereal grains towards improved determination of their water content. A reliable evaluation of the soil textural attributes (e.g. the specific surface area mentioned above) and its water content is essential for intensive irrigation and fertilization processes and within extensive precision agriculture management. The findings of the present research project are expected to improve the determination of cereal grain water content by on-line dielectric methods. A precise evaluation of grain water content is essential for pricing and evaluation of drying-before-storage requirements, issues involving energy savings and commercial aspects of major economic importance to the American agriculture. The results and methodologies developed within the above mentioned side studies are expected to be beneficial to also other industrial and environmental practices requiring the water content determination and characterization of granular materials.
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Perdomo and Payer. L51736 Chemical and Electrochemical Conditions on Steel at Disbonded Coatings. Pipeline Research Council International, Inc. (PRCI), 1995. http://dx.doi.org/10.55274/r0010266.
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The objective of this research was to study the effects of cathodic protection at coating holidays and associated areas of disbondment through simultaneous determination of the electro-chemical reactions and chemical changes taking place in the environment adjacent to the steel substrate. Primary parameters of interest were applied potential, solution conductivity, pH oxygen in solution. The experimental plan was comprised of six interrelated studies involving both laboratory simulations and modeling. It was found that an effective CP system provides sufficient current flow at the exposed steel surface to modify the ground water in the immediate environment by lowering soluble oxygen levels and increasing its alkalinity. Further, corrosion protection is achieved in the shielded areas under the disbonded coating where current flow is minimal, through this chemical modification of the aqueous environment, and it is not necessary that current flow into all of the disbonded region. Three conditions of import to pipeline corrosion protection were also simulated in this investigation. Chemical environment and electric potential distribution within disbond regions were measured for the affects of interruption and reapplication of current; the occurrence of wet/dry cycles at the holiday and the presence of prior corrosion products.