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Статті в журналах з теми "CRIM (Complex Refractive Index Model)":
1
Zadhoush, Hossain, Antonios Giannopoulos, and Iraklis Giannakis. "Optimising the Complex Refractive Index Model for Estimating the Permittivity of Heterogeneous Concrete Models." Remote Sensing 13, no. 4 (February 16, 2021): 723. http://dx.doi.org/10.3390/rs13040723.
Анотація:
Estimating the permittivity of heterogeneous mixtures based on the permittivity of their components is of high importance with many applications in ground penetrating radar (GPR) and in electrodynamics-based sensing in general. Complex Refractive Index Model (CRIM) is the most mainstream approach for estimating the bulk permittivity of heterogeneous materials and has been widely applied for GPR applications. The popularity of CRIM is primarily based on its simplicity while its accuracy has never been rigorously tested. In the current study, an optimised shape factor is derived that is fine-tuned for modelling the dielectric properties of concrete. The bulk permittivity of concrete is expressed with respect to its components i.e., aggregate particles, cement particles, air-voids and volumetric water fraction. Different combinations of the above materials are accurately modelled using the Finite-Difference Time-Domain (FDTD) method. The numerically estimated bulk permittivity is then used to fine-tune the shape factor of the CRIM model. Then, using laboratory measurements it is shown that the revised CRIM model over-performs the default shape factor and provides with more accurate estimations of the bulk permittivity of concrete.
2
Hu, Jun, Xinbin Wang, Fujun Zhang, and Yuanke Zhao. "Experimental Study on the Variation of Soil Dielectric Permittivity under the Influence of Soil Compaction and Water Content." Geofluids 2022 (November 18, 2022): 1–9. http://dx.doi.org/10.1155/2022/3575541.
Анотація:
The dielectric permittivity of common soils is mainly controlled by water content and porosity, while the latter is closely related to the characteristics of compaction. By studying the changes in dielectric permittivity of soil samples with different soil water content and compaction levels, the influence of the controlling factors on the relationship model between soil water content and dielectric permittivity can be evaluated. In this paper, network analyzer was used to measure the dielectric permittivity of 7 groups of soil samples with gravimetric water content ranging from 8.09% to 14.52% and dry density ranging from 1.61 g/cm3 to 1.96 g/cm3. The results show that the dielectric permittivity increases with the increase of water content and dry density, and the effect of water content on permittivity is more significant for soils with higher dry density. Furthermore, when the water content is less than or equal to the optimal water content, Topp formula and the complex refractive index model (CRIM) can better predict the soil dry density. When the water content approaches the saturated state of soil, there is a deviation between the predicted value and the actual value. At last, the modified Topp formula and the complex refractive index model (CRIM) can accurately predict soil compactness. This provides an important basis for rapid detection of water content and compactness of highway subgrade soil by ground penetrating radar.
3
Zhong, Yanhui, Yanlong Gao, Bei Zhang, Songtao Li, Hongchuan Cui, Xiaolong Li, and Han Zhao. "Experimental Study on the Dielectric Model of Common Asphalt Pavement Surface Materials Based on the L-R Model." Advances in Civil Engineering 2021 (May 26, 2021): 1–8. http://dx.doi.org/10.1155/2021/6667101.
Анотація:
The establishment of a dielectric model of the asphalt pavement surface material is the premise and key to applying the electromagnetic wave technology to asphalt pavement nondestructive testing. Asphalt pavement can be made of different materials, including various types of asphalt mixtures. Therefore, in order to study and analyze the dielectric properties of different types of asphalt mixtures and establish a dielectric model of the asphalt pavement surface material, this paper studies four types of asphalt mixtures commonly used in the asphalt pavement surface course. Based on the comparative analysis of three classical models, the complex refractive index method (CRIM), Brown, and Looyenga; based on the L-R model, the linear regression analysis was conducted on the test data. The dielectric models which are suitable for the interpretation of four types of asphalt mixtures were established, and the dielectric model database of asphalt pavement surface materials was extended, which provides theoretical and technical support for nondestructive testing of the asphalt pavement.
4
Du, Erji, Lin Zhao, Defu Zou, Ren Li, Zhiwei Wang, Xiaodong Wu, Guojie Hu, Yonghua Zhao, Guangyue Liu, and Zhe Sun. "Soil Moisture Calibration Equations for Active Layer GPR Detection—a Case Study Specially for the Qinghai–Tibet Plateau Permafrost Regions." Remote Sensing 12, no. 4 (February 11, 2020): 605. http://dx.doi.org/10.3390/rs12040605.
Анотація:
Ground-penetrating radar (GPR) is a convenient geophysical technique for active-layer soil moisture detection in permafrost regions, which is theoretically based on the petrophysical relationship between soil moisture (θ) and the soil dielectric constant (ε). The θ–ε relationship varies with soil type and thus must be calibrated for a specific region or soil type. At present, there is lack of such a relationship for active-layer soil moisture estimation for the Qinghai–Tibet plateau permafrost regions. In this paper, we utilize the Complex Refractive Index Model to establish such a calibration equation that is suitable for active-layer soil moisture estimation with GPR velocity. Based on the relationship between liquid water, temperature, and salinity, the soil water dielectric constant was determined, which varied from 84 to 88, with an average value of 86 within the active layer for our research regions. Based on the calculated soil-water dielectric constant variation range, and the exponent value range within the Complex Refractive Index Model, the exponent value was determined as 0.26 with our field-investigated active-layer soil moisture and dielectric data set. By neglecting the influence of the soil matrix dielectric constant and soil porosity variations on soil moisture estimation at the regional scale, a simple active-layer soil moisture calibration curve, named CRIM, which is suitable for the Qinghai–Tibet plateau permafrost regions, was established. The main shortage of the CRIM calibration equation is that its calculated soil-moisture error will gradually increase with a decreasing GPR velocity and an increasing GPR velocity interpretation error. To avoid this shortage, a direct linear fitting calibration equation, named as υ-fitting, was acquired based on the statistical relationship between the active-layer soil moisture and GPR velocity with our field-investigated data set. When the GPR velocity interpretation error is within ±0.004 m/ns, the maximum moisture error calculated by CRIM is within 0.08 m3/m3. While when the GPR velocity interpretation error is larger than ±0.004 m/ns, a piecewise formula calculation method, combined with the υ-fitting equation when the GPR velocity is lower than 0.07 m/ns and the CRIM equation when the GPR velocity is larger than 0.07 m/ns, was recommended for the active-layer moisture estimation with GPR detection in the Qinghai–Tibet plateau permafrost regions.
5
Berg, Charles R. "A simple, effective‐medium model for water saturation in porous rocks." GEOPHYSICS 60, no. 4 (July 1995): 1070–80. http://dx.doi.org/10.1190/1.1443835.
Анотація:
A general equation for water saturation is derived from effective‐medium theory. A simpler low‐frequency equation is also derived. Both equations are directly solvable for water saturation. The model should be applicable to any granular, water‐wet formation. Additional relationships are derived specifically for application to shaly sandstones, but the model should be applicable to a wide range of rock types, water conductivities, and tool frequencies. In the derivation, hydrocarbons are included in the matrix component of the equation and the combined “matrix” elements are treated as resistors in parallel. The low‐frequency equation is compared to various approaches to calculation of water saturation, such as Dual‐Water, Waxman‐Smits, and Bussian. The general equation is compared to three‐component effective medium, porosity index, and complex refractive index models (CRIM). The model is proven to work on experimental data under a wide range of frequencies and water conductivities. It is recommended that the new saturation model be used for nearly all types of electrical saturation calculation, whether the measurements are from standard resistivity tools or from dielectric tools.
6
Liu, Zonghui, Yinghao Lan, Xiaolei Zhang, Fanzheng Zeng, and Chuanghui Li. "A rapid detection method for diesel content in diesel-contaminated soil based on dielectric measurement and oven-drying tests." IOP Conference Series: Earth and Environmental Science 1335, no. 1 (May 1, 2024): 012036. http://dx.doi.org/10.1088/1755-1315/1335/1/012036.
Анотація:
Abstract Geophysical testing techniques have been successfully applied to identify light non-aqueous phase liquids in soils, but challenges remain in rapidly detecting contaminant content. Detection of contaminants in soil using geophysical testing techniques relies on sensors sensitive to electrical and electromagnetic parameter changes. In this study, the complex permittivity of silty clay contaminated with 0# diesel was measured using an open-ended coaxial probe at frequencies from 200–3000 MHz, and the four-phase dielectric mixing models were evaluated. The measurement results showed that the complex refractive index method (CRIM) model provided a better match with the real permittivity of the four-phase system between 500–3000 MHz with relative errors within an acceptable range of 4%. To eliminate the unknown variable in the CRIM model, an improved equation for the relationship between water content and diesel content of the watery diesel-contaminated silty clay was established by the oven-drying method. Thus, a method for the rapid quantitative detection of the diesel content in contaminated soil has been developed based on dielectric measurement and oven-drying tests. The relative error between the calculated and actual set diesel content for ten manually configured diesel-contaminated soil samples was within 10%, with a maximum error of 15.75%.
7
Bumberger, Jan, Juliane Mai, Felix Schmidt, Peter Lünenschloß, Norman Wagner, and Hannes Töpfer. "Spatial Retrieval of Broadband Dielectric Spectra." Sensors 18, no. 9 (August 23, 2018): 2780. http://dx.doi.org/10.3390/s18092780.
Анотація:
A broadband soil dielectric spectra retrieval approach ( 1 MHz– 2 GHz) has been implemented for a layered half space. The inversion kernel consists of a two-port transmission line forward model in the frequency domain and a constitutive material equation based on a power law soil mixture rule (Complex Refractive Index Model - CRIM). The spatially-distributed retrieval of broadband dielectric spectra was achieved with a global optimization approach based on a Shuffled Complex Evolution (SCE) algorithm using the full set of the scattering parameters. For each layer, the broadband dielectric spectra were retrieved with the corresponding parameters thickness, porosity, water saturation and electrical conductivity of the aqueous pore solution. For the validation of the approach, a coaxial transmission line cell measured with a network analyzer was used. The possibilities and limitations of the inverse parameter estimation were numerically analyzed in four scenarios. Expected and retrieved layer thicknesses, soil properties and broadband dielectric spectra in each scenario were in reasonable agreement. Hence, the model is suitable for an estimation of in-homogeneous material parameter distributions. Moreover, the proposed frequency domain approach allows an automatic adaptation of layer number and thickness or regular grids in time and/or space.
8
Abdorahimi, Danial, and Ali M. Sadeghioon. "Comparison of Radio Frequency Path Loss Models in Soil for Wireless Underground Sensor Networks." Journal of Sensor and Actuator Networks 8, no. 2 (June 22, 2019): 35. http://dx.doi.org/10.3390/jsan8020035.
Анотація:
A wireless Underground Sensor Network (WUSN) is a group of sensors that collectively communicate through the underground medium. Radio Frequency (RF) signal transmission of the sensors through the ground is the most challenging aspects of a WUSN due to the high attenuation of the electromagnetic (EM) signal in the soil. Signals are often required to travel through soils with a high density or water content and generally through a non-isotropic and non-homogenous soil mixture with different boundaries, both of which can attenuate the signal sharply. The variability of the these conditions and complexity of the behaviour of signal attenuation with respect to these parameters makes accurate estimation of EM signal attenuation in soil challenging. Two main EM signal attenuation models exist to estimate attenuation (modified-Friis and Complex Refractive Index Model-Fresnel (CRIM-Fresnel). These were reviewed and a methodology was developed in order to measure the attenuation of the EM signals in the laboratory. Results from the laboratory measurements were compared with the estimation values calculated from the attenuation models. These comparisons showed a large difference between the estimated values by the models. In addition, analysis of the comparison tests showed that the CRIM-Fresnel model provides a better estimation of attenuation in samples with lower permittivity values while the modified-Friis model had a higher accuracy in samples with higher clay/water content which have higher permittivity values.
9
Chen, Huangye, and Zoya Heidari. "Pore-Scale Joint Evaluation of Dielectric Permittivity and Electrical Resistivity for Assessment of Hydrocarbon Saturation Using Numerical Simulations." SPE Journal 21, no. 06 (May 19, 2016): 1930–42. http://dx.doi.org/10.2118/170973-pa.
Анотація:
Summary Complex pore geometry and composition, as well as anisotropic behavior and heterogeneity, can affect physical properties of rocks such as electrical resistivity and dielectric permittivity. The aforementioned physical properties are used to estimate in-situ petrophysical properties of the formation such as hydrocarbon saturation. In the application of conventional methods for interpretation of electrical-resistivity (e.g., Archie's equation and the dual-water model) and dielectric-permittivity measurements [e.g., complex refractive index model (CRIM)], the impacts of complex pore structure (e.g., kerogen porosity and intergranular pores), pyrite, and conductive mature kerogen have not been taken into account. These limitations cause significant uncertainty in estimates of water saturation. In this paper, we introduce a new method that combines interpretation of dielectric-permittivity and electrical-resistivity measurements to improve assessment of hydrocarbon saturation. The combined interpretation of dielectric-permittivity and electrical-resistivity measurements enables assimilating spatial distribution of rock components (e.g., pore, kerogen, and pyrite networks) in conventional models. We start with pore-scale numerical simulations of electrical resistivity and dielectric permittivity of fluid-bearing porous media to investigate the structure of pore and matrix constituents in these measurements. The inputs to these simulators are 3D pore-scale images. We then introduce an analytical model that combines resistivity and permittivity measurements to assess water-filled porosity and hydrocarbon saturation. We apply the new method to actual digital sandstones and synthetic digital organic-rich mudrock samples. The relative errors (compared with actual values estimated from image processing) in the estimate of water-filled porosity through our new method are all within the 10% range. In the case of digital sandstone samples, CRIM provided reasonable estimates of water-filled porosity, with only four out of twenty-one estimates beyond 10% relative error, with the maximum error of 30%. However, in the case of synthetic digital organic-rich mudrocks, six out of ten estimates for water-filled porosity were beyond 10% with CRIM, with the maximum error of 40%. Therefore, the improvement was more significant in the case of organic-rich mudrocks with complex pore structure. In the case of synthetic digital organic-rich mudrock samples, our simulation results confirm that not only the pore structure but also spatial distribution and tortuosity of water, kerogen, and pyrite networks affect the measurements of dielectric permittivity and electrical resistivity. Taking into account these parameters through the joint interpretation of dielectric-permittivity and electrical-resistivity measurements significantly improves assessment of hydrocarbon saturation.
10
Manning, Michael J., and Kumud A. Athavale. "Dielectric properties of pyrite samples at 1 100 MHz." GEOPHYSICS 51, no. 1 (January 1986): 172–82. http://dx.doi.org/10.1190/1.1442030.
Анотація:
Pyrite occurs in many petroleum reservoirs and significantly affects density and electric well logs even in low concentrations. Ultrahigh‐frequency dielectric measurements also are significantly affected by pyrite. Dielectric properties of core samples containing approximately 50 percent pyrite by volume were measured from 800 to 1 200 MHz ([Formula: see text]). These measurements demonstrate the high, complex dielectric permittivity of pyrite and provide data for calculation of pyrite permittivity at ultrahigh frequencies. The measured complex‐permittivity of water‐saturated pyrite nodules is approximately [Formula: see text] at 1 100 MHz and 25 °C. The measured permittivity of pyrite nodules depends upon the concentration of pyrite and only slightly on saturating‐water salinity. Two geometric mixing models, the complex refractive‐index method (CRIM) and a modified Hanai‐Bruggeman‐Sen (HBS) model, are used to analyze the data. CRIM analysis of water‐saturated and oil‐saturated core data gives inconsistent results because the porosity is poorly connected. HBS, with a variable dielectric exponent, provides more consistent results. [Formula: see text] is the complex permittivity of pyrite at 1 100 MHz and 25 °C determined by applying HBS to laboratory measurements. CRIM‐determined pyrite permittivity is about 50 percent greater in both real and imaginary parts. This high [Formula: see text] has important implications for high‐frequency dielectric well‐logging tools. Signal amplitudes are highly attenuated in formations with large concentrations of pyrite. Where pyrite nodules occur, wave scattering may cause inconsistent data indicative of formation heterogeneity. Low concentration, disseminated pyrite increases the rock “matrix” permittivity. Mineralogical variations, particularly in trace quantities of heavy minerals, are a likely explanation for significant variations in measured matrix permittivities for sandstones. Comparison of pyrite permittivity with available values for the permittivity of rutile, another heavy mineral found in sedimentary rocks, suggests employing pyrite and rutile in artificial sandpack experiments. The real parts of pyrite and rutile permittivities are nearly equal, but the imaginary part of the permittivity of rutile is lower than pyrite by about [Formula: see text]. Experiments with both minerals could test mixing models and the effects of distribution in mixtures of conductive minerals.
Дисертації з теми "CRIM (Complex Refractive Index Model)":
1
Cousin, Théau. "Modélisation et simulation numérique du problème inverse en tomographie électromagnétique." Electronic Thesis or Diss., Normandie, 2024. http://www.theses.fr/2024NORMIR03.
Анотація:
Cette thèse s'inscrit dans un projet de recherche qui a pour ambition de développer, dans une démarche écologique, une méthodologie permettant de retrouver la densité des matériaux du génie civil. L'objectif est de remplacer une méthode invasive et nucléaire par une approche non destructive et électromagnétique. Les travaux de cette thèse sont issues d'une collaboration Cifre entre le Cerema, Routes de France et le Laboratoire de Mathématiques de l'INSA de Rouen Normandie (LMI). Des premiers travaux ont permis d'établir un lien entre la densité et la permittivité diélectrique d'un matériau, ce qui a conduit l'équipe ENDSUM du Cerema Normandie à réaliser un banc permettant d'émettre et de recevoir des ondes électromagnétiques. Il est équipé de moteurs pas à pas pour les antennes et un moteur pour le support, permettant d'accéder à des mesures de type tomographie. L'objectif de cette thèse est de mettre en place un solveur permettant de réaliser une inversion sur les données générées par ce banc afin de retrouver la permittivité et in fine la compacité. Cela implique la modélisation et la simulation numérique de ce système, basée sur la diffraction des ondes électromagnétiques régie par les équations de Maxwell que nous avons étudiés en ordre 2. La réalisation de ce solveur 3D a nécessité l'implémentation d'une méthode type Élément Finis, basée sur les Éléments Finis de Nédelec. La prise en compte du caractère non borné du domaine a été réalisée grâce à l'implémentation de Perfectly Matched Layers. Afin d'optimiser l'implémentation, nous avons également mis en place une vectorisation de l'assemblage des matrices de discrétisation et implémenté une méthode de décomposition de domaine. Finalement, la résolution du problème de minimisation s'est faite par une approche de type Gauss-Newton utilisant la méthode d'état adjoints pour le calcul de la matrice Hessienne. Cette résolution est combinée avec une régularisation de Tikhonov dite semi-quadratique permettant d'accentuer le contraste dans la permittivité recherchée. La modélisation du banc a également nécessité des travaux sur le calibrage des antennes utilisées. Nous avons réadapté les travaux dans le but de considérer les antennes comme une source ponctuelle associée à une onde sphérique et mis en place un procédé expérimental permettant de corriger les signaux reçusThis thesis is part of a research project aiming to develop, in an ecological approach, a methodology for retrieving the density of civil engineering materials. The objective is to replace an invasive and nuclear method with a non-destructive and electromagnetic approach. The work of this thesis stems from a CIFRE collaboration between Cerema, Routes de France, and the Laboratory of Mathematics at INSA Rouen Normandie (LMI).The initial work has established a relationship between the density and the dielectric permittivity of a material, leading the ENDSUM team at Cerema Normandie to develop a bench capable of emitting and receiving electromagnetic waves. It is equipped with stepper motors for the antennas and a motor for the support, enabling tomography-type measurements. The objective of this thesis is to implement a solver capable of performing inversion on the data generated by this bench to retrieve the permittivity and ultimately the compactness. This involves the numerical modeling and simulation of this system, based on the diffraction of electromagnetic waves governed by the Maxwell equations we studied in second order. The development of this 3D solver required the implementation of a Finite Element type method, based on Nedelec Finite Elements. The consideration of the unbounded nature of the domain was achieved through the implementation of Perfectly Matched Layers. To optimize the implementation, we also introduced vectorization of the discretization matrix assembly and implemented a domain decomposition method. Finally, the resolution of the minimization problem was carried out using a Gauss-Newton approach utilizing the adjoint state method for computing the Hessian matrix. This resolution is combined with a semi-quadratic Tikhonov regularization method to enhance the contrast in the desired permittivity.The modeling of the bench also required work on the calibration of the antennas used. We have readapted previous work to consider the antennas as a point source associated with a spherical wave and implemented an experimental process to correct the received signals
2
Bonnal, Thomas. "Développements de modèles optiques et de méthodes non supervisées de résolution des problèmes bilinéaires : application à l’imagerie vibrationnelle." Thesis, Lyon, 2018. http://www.theses.fr/2018LYSE1063.
Анотація:
La caractérisation fine des matériaux inorganiques nécessite d'avoir accès à des informations complémentaires de celles apportées par des techniques d'analyse élémentaire ou de diffraction. La spectroscopie infrarouge à transformée de Fourier permet de caractériser les liaisons covalentes et l'environnement des groupes fonctionnels dans les matériaux. C'est donc une technique de choix pour l'étude des matériaux hydratés, amorphes ou sujets à des phénomènes de vieillissement. En couplant cette technique à une platine de déplacement, il est possible de réaliser des cartographies des phases sur quelques centimètres carrés : c'est la microscopie infrarouge. Cette thèse développe plus particulièrement l'utilisation de la lumière réfléchie au travers de l'étude de la réflexion spéculaire et de la réflexion totale atténuée (ATR).Après une première partie se focalisant sur les méthodes d'acquisitions disponibles, une seconde partie s'attache à obtenir de manière non supervisée les cartographies chimiques associées aux concentrations relatives des différents composants présents dans la zone analysée. Des techniques de réduction de données et d'analyse factorielle sont mises en place afin d'estimer le nombre de composants chimiques et leurs spectres relatifs ; des problèmes de minimisation sous contraintes sont résolus pour extraire l'information chimique. La réflexion spéculaire ne nécessite aucun contact avec l‘échantillon et, de ce fait, n'entraine aucune altération de la surface analysée. C'est sur le papier une technique de choix pour suivre l'évolution d'un matériau. Cependant, elle souffre de la complexité d'interprétation liée à l'allure des spectres obtenus. Afin de développer la cartographie issue de la réflexion spéculaire, des modèles prenant en compte l'optique géométrique, l'optique ondulatoire, des corrections d'interférogrammes et des méthodes classiques d'homogénéisation ont été développés. Ce travail a permis d'aboutir à un modèle optique liant les spectres issus de la réflexion spéculaire avec les concentrations relatives des composants. Ce modèle tient compte de la polarisation, de l'angle d'incidence et utilise les constantes diélectriques du matériau. Ce modèle a été validé sur un matériau contenant trois composants distincts facilement identifiables en infrarouge et spécialement mis en forme pour cette étude. Ce modèle a ouvert la voie à l'utilisation innovante de lumières polarisées elliptiquement pour déterminer l'indice de réfraction complexe d'un matériau. Ainsi, des spectroscopes infrarouges couplés à un accessoire de contrôle de l'angle d'incidence peuvent être utilisés en complément de l'ellipsométrieComplementary information, to that provided by elemental analysis and diffraction techniques, is needed to characterize inorganic materials. Fourier Transform Infrared spectroscopy enables to characterize covalent bonds and the environment of functional groups in materials. Thus, it is a technique of interest to study hydrated materials, amorphous materials or any materials, which may experience ageing phenomena. By combining this technique with a micrometric motorized stage, cartographies of chemical compounds can be obtained on several square millimeters: this is the infrared microscopy technique. This Ph.D. thesis focuses on the use of reflected light, in particular through the study of specular reflection and of Attenuated Total Reflectance (ATR). After a first part focused on the different acquisition set-ups, a second part covers the unsupervised methodologies of resolution employed to obtain chemical maps. They result in one map for each component present in the analyzed area. Dimensions reduction techniques and multivariate statistics techniques are implemented to estimate the number of components and their infrared spectra; minimization problems under constraints are solved to retrieve chemical information. When specular reflection is used to acquire spectra, no contact is made with the sample, thus no damage of the analyzed area occurs during the acquisition. A priori, it is a great technique to study the evolution of a material. However, this technique suffers from the complexity of interpretation of the resulting spectra. With the objective to democratize the use of specular reflection to obtain chemical maps, models based on geometrical optics and including diffraction, correction of interferograms and classical homogenization techniques have been developed. This work resulted in an optical model linking the angle of incidence, the polarization state and the dielectric optical constants of the material with the reflected light, which is measured. A model material, constituted of three distinct phases, detectable in the infrared range, has specially been fabricated to validate this optical model. This model set the stage for the use of elliptically polarized light in the determining of the complex refractive indices of materials in the infrared range. Thanks to this development, infrared spectroscopes, equipped with a classical set-up to control the angle of incidence, can now be used in addition to ellipsometry techniques
Частини книг з теми "CRIM (Complex Refractive Index Model)":
1
Ayub Hamdani, Mursal, and Gausia Qazi. "Modelling Fabrication Variability in Silicon Photonic Devices." In Photonic Materials: Recent Advances and Emerging Applications, 265–83. BENTHAM SCIENCE PUBLISHERS, 2023. http://dx.doi.org/10.2174/9789815049756123010016.
Анотація:
Silicon photonics allows for high yield and complex integration with large processing, packaging, and testing availability. Using silicon as a material leverages the use of the existing CMOS infrastructure with hybrid and epitaxial layer integration, allowing photonic system-on-chip. Although high refractive index contrast with sub micrometer waveguide dimensions allows a dense integration, sensitivity to fabrication variations shows an increased effect. This sensitivity shows a cumulative effect on the optical properties of complex silicon photonic circuits such as lattice filters, and wavelength division multiplexers (WDM). This increases the demand for model fabrication variation at the design stage itself since the fabless users have no insights into the process specifications. As a result, reliability modelling of photonic circuits has shown significant interest in recent years. This is done by using efficient behavioural models at the circuit level and then applying random variations in the model parameters to assess the impact of these variations. In this chapter, different approaches to modelling fabrication variations in photonic integrated circuits, such as Monte Carlo (MC), Stochastic Collocation (SC), and Polynomial Chaos Expansion (PCE) are reviewed. These methods employ random distribution to the varying parameters with the correlation between different parameter sets fixed. Virtual Wafer-based MC (VW-MC) allows layout-aware variability analysis, where the placement of circuit components on the layout coordinates is exported to the circuit design for dependence analysis. Using these methods, mitigation strategies to counter the manufacturing variations such as thermal compensation, and tapered designs are quantitatively evaluated by appropriate yield analysis and design for manufacturability.
Тези доповідей конференцій з теми "CRIM (Complex Refractive Index Model)":
1
Azizoglu, Zulkuf, Zoya Heidari, Leonardo Goncalves, Lucas Abreu Blanes De Oliveira, and Moacyr Silva Do Nascimento Neto. "Assessment of Water Saturation Using Dielectric Permittivity Measurements in Formations with Complex Pore Structure: Application to the Core- and Log- Scale Domains." In SPE Annual Technical Conference and Exhibition. SPE, 2021. http://dx.doi.org/10.2118/205987-ms.
Анотація:
Abstract Broadband dielectric dispersion measurements are attractive options for assessment of water-filled pore volume, especially when quantifying salt concentration is challenging. However, conventional models for interpretation of dielectric measurements such as Complex Refractive Index Model (CRIM) and Maxwell Garnett (MG) model require oversimplifying assumptions about pore structure and distribution of constituting fluids/minerals. Therefore, dielectric-based estimates of water saturation are often not reliable in the presence of complex pore structure, rock composition, and rock fabric (i.e., spatial distribution of solid/fluid components). The objectives of this paper are (a) to propose a simple workflow for interpretation of dielectric permittivity measurements in log-scale domain, which takes the impacts of complex pore geometry and distribution of minerals into account, (b) to experimentally verify the reliability of the introduced workflow in the core-scale domain, and (c) to apply the introduced workflow for well-log-based assessment of water saturation. The dielectric permittivity model includes tortuosity-dependent parameters to honor the complexity of the pore structure and rock fabric for interpretation of broadband dielectric dispersion measurements. We estimate tortuosity-dependent parameters for each rock type from dielectric permittivity measurements conducted on core samples. To verify the reliability of dielectric-based water saturation model, we conduct experimental measurements on core plugs taken from a carbonate formation with complex pore structures. We also introduce a workflow for applying the introduced model to dielectric dispersion well logs for depth-by-depth assessment of water saturation. The tortuosity-dependent parameters in log-scale domain can be estimated either via experimental core-scale calibration, well logs in fully water-saturated zones, or pore-scale evaluation in each rock type. The first approach is adopted in this paper. We successfully applied the introduced model on core samples and well logs from a pre-salt formation in Santos Basin. In the core-scale domain, the estimated water saturation using the introduced model resulted in an average relative error of less than 11% (compared to gravimetric measurements). The introduced workflow improved water saturation estimates by 91% compared to CRIM. Results confirmed the reliability of the new dielectric model. In application to well logs, we observed significant improvements in water saturation estimates compared to cases where a conventional effective medium model (i.e., CRIM) was used. The documented results from both core-scale and well-log-scale applications of the introduced method emphasize on the importance of honoring pore structure in the interpretation of dielectric measurements.
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Azizoglu, Zulkuf, and Zoya Heidari. "INTERPRETATION OF MULTI-FREQUENCY DIELECTRIC PERMITTIVITY MEASUREMENTS FOR ASSESSMENT OF WATER SATURATION IN CARBONATE FORMATIONS WITH COMPLEX PORE STRUCTURE." In 2021 SPWLA 62nd Annual Logging Symposium Online. Society of Petrophysicists and Well Log Analysts, 2021. http://dx.doi.org/10.30632/spwla-2021-0034.
Анотація:
Broadband relative dielectric dispersion measurements are considered interesting options for assessment of water-filled pore volume. Conventional models such as Complex Refractive Index Model (CRIM) and Maxwell Garnett (MG), often overlook or oversimplify the complexity of pore structure, geometrical distribution of the constituting fluids, and spatial distribution of minerals. This yields to significant errors in assessment of water saturation especially in rocks with complex pore structure. Therefore, it becomes important to quantify the impacts of pore structure and spatial distribution of minerals on broadband relative dielectric dispersion measurements to be able to make decisions about reliability of water saturation estimates from these measurements in a given formation. The objectives of this paper are (a) to quantify the impacts of pore structure and spatial distribution of minerals on relative dielectric permittivity measurements in a wide range of frequencies, (b) to propose a new simple and physically meaningful workflow, which honors pore geometry and spatial distribution of minerals to enhance fluid saturation assessment using relative dielectric permittivity measurements, (c) to verify the reliability of the introduced model in the pore-scale domain. First, we perform numerical simulations of relative dielectric dispersion measurements in the frequency range of 20 MHz to 1 GHz in the pore-scale domain. The input to the numerical simulator includes pore-scale images of actual complex carbonate rock samples. We use a physically meaningful model which honors spatial distribution of the rock constituents for the multi-frequency interpretation of relative dielectric response. To verify the reliability of the model in multiple frequencies, we apply the model to the results of relative dielectric simulations in the pore-scale domain on 3D computed tomography scan (CT-scan) images of carbonate rock samples, which are synthetically saturated to obtain a wide range of water saturation. We successfully verified the reliability of the introduced model in the pore-scale domain using carbonate rock samples with multi-modal pore-size distribution. Estimated water saturations from the results of simulations at 1 GHz resulted in an average relative error of less than 4%. We observed measurable improvements in fluid saturation estimates compared to the cases which CRIM or MG models are used. Results demonstrated that application of conventional models to estimate water saturation from relative dielectric response is not reliable in frequencies below 1 GHz.
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Azizoglu, Zulkuf, Zoya Heidari, Leonardo Goncalves, Lucas Abreu Blanes de Oliveira, Moacyr Silva do Nascimento Neto, and Rodolfo Araujo Victor. "Simultaneous Assessment of Water Saturation and Water Salinity From the Joint Multi-Frequency Interpretation of Real and Imaginary Parts of Dielectric Permittivity Measurements." In 2022 SPWLA 63rd Annual Symposium. Society of Petrophysicists and Well Log Analysts, 2022. http://dx.doi.org/10.30632/spwla-2022-0117.
Анотація:
Fluid saturations and distributions, water salinity, pore structure, and porosity affect dielectric permittivity measurements. However, the conventional dielectric permittivity mixture models, such as Complex Refractive Index Model (CRIM) and Hanai-Bruggeman (HB) do not quantitatively include the cumulative effect of the aforementioned petrophysical properties. Moreover, the effect of salt concentration on multi-frequency dielectric permittivity measurements still needs to be investigated. The objectives of this paper are (a) to investigate the effect of salt concentration on complex multi-frequency dielectric permittivity responses in rocks with complex pore structure, (b) to develop a new workflow for estimating multi-frequency dielectric permittivity of rock samples taking into account the complexity of pore structure, different polarization mechanisms, porosity, water saturation, and salt concentration, and (c) to develop an inversion algorithm to simultaneously estimate water saturation and salinity from dielectric dispersion data. First, we conduct dielectric permittivity experiments on fully brine-saturated rock samples. Then, we change the salinity of the samples and perform dielectric permittivity experiments on the rock samples at different water salinity levels. Next, we develop a new rock-physics workflow which includes the combined effect of the aforementioned petrophysical properties. The new workflow calculates the multi-frequency complex dielectric permittivity responses of synthetic rock samples. Then, we use an automated inversion algorithm to simultaneously estimate water saturation and salinity of actual rock samples from the joint interpretation of the real and imaginary parts of multi-frequency dielectric permittivity measurements. We successfully verified the reliability of the new workflow in the core-scale domain using 12 different rock samples in the Barra Velha formation. The new workflow simultaneously estimated water saturation and salinity with average relative errors less than 12% and 14%, respectively. Moreover, we observed that the average relative errors between the experimentally observed and calculated dielectric permittivity that are obtained from the introduced mixture model, CRIM, and HB are 11%, 121%, and 26%, respectively. We demonstrated that the effect of salt concentration could have significant effects on dielectric permittivity responses up to 3 GHz and has to be reliably taken into account in interpretation of dielectric measurements. The multi-frequency joint interpretation of the real and imaginary parts of dielectric permittivity measurements makes the introduced workflow a robust interpretation technique in the presence of uncertainties in the estimates of the formation water salinity. Moreover, unlike the conventional dielectric mixture models, the introduced workflow honors the complexity of pore structure and composition, water salinity, and different polarization mechanisms.
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Azizoglu, Zulkuf, and Zoya Heidari. "The Effect of Salt Concentration on Dielectric Permittivity and Interfacial Polarization in Carbonate Rocks with Complex Pore Structure." In SPE Annual Technical Conference and Exhibition. SPE, 2022. http://dx.doi.org/10.2118/210315-ms.
Анотація:
Abstract Broadband dielectric dispersion measurements are attractive options for assessment of water-filled Dielectric permittivity is influenced by salinity as well as other rock/fluid properties. However, the effect of salinity on Maxwell-Wagner polarization (i.e., interfacial polarization) and dielectric permittivity in rock samples with complex pore structure requires further investigation. The objectives of this work are (a) to perform frequency domain dielectric permittivity numerical simulations on 3-dimensional (3D) pore-scale rock samples at different salt concentration levels, (b) to quantify the effect of salinity on dielectric permittivity and interfacial polarization in the frequency range between 20 MHz to 5 GHz, and (c) to quantify the frequency at which the interfacial polarization diminishes. We first perform pore-scale frequency domain dielectric permittivity simulations in fully water-saturated carbonate samples with complex pore structure to obtain the complex dielectric permittivity in the frequency range of 0.02-5 GHz and at different salinity levels. Next, we numerically create partially water/hydrocarbon-saturated water-wet samples and perform simulations at different salinity and water saturation levels to investigate the combined effect of salinity and water saturation on dielectric permittivity. Finally, we investigate how reliable conventional mixing models, such as Complex Refractive Index Model (CRIM) and Hanai-Bruggeman (HB), are in assessment of water saturation at different salinity levels. We used 3D pore-scale rock samples with complex pore structure from Austin Chalk, Estaillades Limestone, and Happy Spraberry formations. The increase in the salinity from 2 PPT to 50 PPT resulted in the dielectric constant to increase by 25% at 20 MHz. Similarly, an increase in salinity from 2 PPT to 50 PPT resulted in electrical conductivity to increase 10 times at 20 MHz. However, at 5 GHz the difference between the dielectric constants of the samples at different salinities was negligible. We demonstrated that the frequency at which the interfacial polarization becomes negligible is above 1 GHz. Thus, an accurate salinity assumption is required in the interpretation of conventional dielectric mixture models in carbonate formations. Finally, we observed 52% and 42% average relative errors in water saturation quantification when applying CRIM and HB models, respectively. The results also indicated that conventional models should not be used in the presence of uncertainty in salinity at lower frequencies. The results of this work quantified the frequency at which the water-filled pore volume rather than the Maxwell-Wagner polarization controls the dielectric constant of rock samples saturated with wide range of brine salinity. Moreover, results demonstrated that unlike the samples with relatively simple pore geometry (e.g., sandstone formations), the dielectric constant of the rock samples with complex pore structure may still be affected by the interfacial polarization even at 1 GHz. Moreover, the results suggested that the conventional mixture methods cannot reliably take into account salt concentration of formation water, and this can lead to significant errors in reserves assessment.
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Wang, Hanming, Aygul Kostinovsky, and Mehrnoosh Saneifar. "Case Study of Dielectric Logging in the Permian Basin: An Opportunity for Solving Petrophysical Challenges in Tight Formations." In SPE Annual Technical Conference and Exhibition. SPE, 2023. http://dx.doi.org/10.2118/214819-ms.
Анотація:
Abstract High uncertainty of water saturation from petrophysical interpretation has been recognized as a challenge in the Permian Basin for years. Such challenges include, but are not limited to, variable Archie's parameters (m and n) due to the formation heterogeneity, variable formation water salinity, and thinly bedded nature. These challenges make dielectric logging a unique opportunity in tight unconventional reservoirs. Dielectric logging is sensitive to water content and provides water-filled porosity without having to know Archie's empirical parameters or water salinities, which are required with resistivity log interpretation. In addition, dielectric logging offers high vertical resolution logs to address thin-bed issues. Moreover, because of the extremely low permeability of the shale reservoirs, there is effectively no invasion of the borehole fluids into the formation. Thus, in these reservoirs, dielectric logging directly provides water-filled porosity of the undisturbed zone. In this paper, we will share two case studies of dielectric logging in several formations of the Permian Basin which wide-band dielectric measurements on core samples in the lab were also made. A recently developed interpretation model, DCRIM (Dual-frequency Complex Refractive Index Method) is tested and further extended to a wider frequency band. It is observed that the DCRIM method is valid at the frequency as low as 100 MHz in the studied wells. Compared with several traditional interpretation methods such as CRIM, bi-modal, and SMD methods, the new method has significant advantages over the existing approaches since it does not require inputs for either matrix or hydrocarbon permittivity, including kerogen permittivity, to derive water-filled porosity as do existing approaches. The new method enables the elimination of all associated uncertainties with formation mineral models in complex lithologies, unknown mineral permittivity endpoints and, most importantly, the poorly defined permittivity of kerogen. It only requires the relatively well-known input of formation temperature. Thus, the new method provides a more robust, streamlined, and consistent interpretation of the dielectric dispersion logs in tight rocks and potentially reduces the uncertainty on the estimation of hydrocarbons in place. The new method was applied in two selected wells with the availability of water saturation from core samples and other advanced logs such as Nuclear Magnetic Resonance (NMR). After Quality Assurance/Quality Control (QA/QC) the raw dielectric logging data, the water-filled porosity (or water saturation when the total porosity is available) from dielectric logging data is benchmarked against the core data. It is concluded the new method using dielectric logging data from two frequencies presents a good solution to reduce the petrophysics uncertainty and should be considered as a reliable alternative of resistivity-based interpretation when optimizing petrophysical analysis workflows in the Permian Basin.
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Mohan, K. Aditya, Xianghui Xiao, and Charles A. Bouman. "Direct model-based tomographic reconstruction of the complex refractive index." In 2016 IEEE International Conference on Image Processing (ICIP). IEEE, 2016. http://dx.doi.org/10.1109/icip.2016.7532659.
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Jannson, Tomasz, and Joanna Jannson. "Nonuniform Bragg holograms with complex refractive index." In OSA Annual Meeting. Washington, D.C.: Optica Publishing Group, 1987. http://dx.doi.org/10.1364/oam.1987.wh4.
Анотація:
It has been known for years that the bandwidth of typical Bragg-Lippmann holograms, based on dichromated gelatin (DCG) and PVA-based polymers, is much broader1 than could be expected based on the fully uniform Kogelnik theory. Indeed the typical holographic processing is highly nonuniform, particularly in the z direction; thus both fundamental parameters of Kogelnik’s theory; the coupling constant and off-Bragg parameter, become functions of the z coordinate.1 This fact constitutes the basis for the more general theory based on the well-known (from quantum mechanics) WKB approximation.1 On the other hand, it became evident that the analysis of UV and XUV holograms2 requires the introduction of both a complex bias refractive-index and refractive-index modulation. Unfortunately, the elegant analytic model based on the WKB method does not hold for highly nonuniform Kogelnik parameters. Such a situation, however, is quite typical in DCG holography where an experimental hologram bandwidth can easily exceed 100 nm, while the theoretical bandwidth, based on Kogelnik’s theory, can still be below 20 nm. Therefore, the generalization in both directions, high-grating constant vertical nonuniformity and complex refractive index, is necessary.
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Liu, Yongmeng, Xv Liu, Zelin Li, Chuanzhi Sun, and Enxiao Liu. "Equivalent thin film model with complex refractive index of resonant micromesh." In 10th International Symposium on Precision Engineering Measurements and Instrumentation (ISPEMI 2018), edited by Jiubin Tan and Jie Lin. SPIE, 2019. http://dx.doi.org/10.1117/12.2521224.
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Zenkova, Polina N., Dmitriy G. Chernov, and Mikhail V. Panchenko. "Complex refractive index in the model of the vertical profile of aerosol optical characteristics in the troposphere of Western Siberia." In 28th International Symposium on Atmospheric and Ocean Optics: Atmospheric Physics, edited by Oleg A. Romanovskii and Gennadii G. Matvienko. SPIE, 2022. http://dx.doi.org/10.1117/12.2644905.
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Fang, Lezheng, and Michael J. Leamy. "Negative Refractive Index in a Two-Dimensional Nonlinear Rotator Lattice." In ASME 2021 International Design Engineering Technical Conferences and Computers and Information in Engineering Conference. American Society of Mechanical Engineers, 2021. http://dx.doi.org/10.1115/detc2021-71840.
Анотація:
Abstract Acoustic metamaterials achieving negative index refraction usually operate linearly over a narrowband of frequency and consist of complex unit cell structures incorporating resonators. In this paper, we propose and analyze a simple, non-resonant, nonlinear rotator lattice structure which can be configured with either a positive or negative index of refraction over a broadband frequency range. The system’s frequency-dependent transmission is studied analytically via a reduced model along the interface of positive and negative refractive index lattices. Results for energy transmission are compared to those obtained using direct numerical simulation and close agreement is documented for small amplitude waves. For larger amplitude waves, a multiple scales analysis approach is used to show that the nonlinearity of the lattice shifts the system’s band structure, inducing amplitude-dependent transmission. For the studied system, the transmission decreases as we increase the incident wave amplitude, agreeing qualitatively with results from direct numerical simulation. At large-enough amplitudes, near the interface the wave amplitude decreases rapidly. As the wave travels further into the media, the amplitude drops, causing the nonlinear effect to decline as well. This decaying envelope does not result in a zero transmission in the far field, as expected from linear theory, and instead, the nonlinearity of the proposed rotator lattice prevents the far-field transmitted wave from surpassing a specific threshold amplitude, regardless of the incident wave. This finding may serve as an inspiration for designing nonlinear wave saturators.