Relevant bibliographies by topics / Dielectrical permittivity

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  2. Dissertations / Theses
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Academic literature on the topic 'Dielectrical permittivity'

Author: Grafiati
Published: 4 June 2025
Last updated: 23 June 2025

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Journal articles on the topic "Dielectrical permittivity"

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Zang, Chong Guang, and Xian Peng Cao. "PANI / MWNTs / EP Composite Microwave Absorbing Coatings Dielectrical and Microwave Absorbing Properties Analysis." Applied Mechanics and Materials 303-306 (February 2013): 2477–80. http://dx.doi.org/10.4028/www.scientific.net/amm.303-306.2477.

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In this paper, the polyaniline (PANI) coated multi-walled carbon nanotubes (MWNTs) was prepared in situ polymerization. Adding PANI/MWNTs into epoxy resin（EP）, we got PANI / MWNTs / EP composite microwave absorbing materials. Through testing permittivity 、permeability and reflection loss of materials, the paper showed the effect of PANI/MWNTS to the dielectrical and microwave absorbing properties of materials.The results showed： PANI/MWNTs had great effect on dielectrical and microwave absorbing properties of materials. But the imaginary permeability was close to 0. That indicated that it mainly consumed electromagnetic wave by dielectric loss. In 200-1000MHZ, materials had better absorbing property and lower reflection loss (-13.6).
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Abd, Abeer. "Studying the mechanical and electrical properties of epoxy with PVC and calcium carbonate filler." International Journal of Engineering & Technology 3, no. 4 (2014): 545. http://dx.doi.org/10.14419/ijet.v3i4.3425.

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In the present research composite material was prepared from epoxy and PVC reinforced with calcium carbonate as a filler material with different percent weight ratios (0.6,1.2,1.8 and 2.4) g.The effect of different weight ratios of calcium carbonate particles and PVC different content on electrical permittivity , dielectrical loss constant, hardness ,young modulus and compression strength were studied. Electrical properties of these composites were investigated by using Fourier transform infrared spectroscopy (FTIR) to study the bonds which enhanced the insulating properties of epoxy material compounded with filler and PVC. The inclusion of CaCO3 in epoxy and (PVC) polymer matrices greatly enhances the physical and mechanical properties of the composite.The experimental results also show that sample (5) compounded with 2.4 g of Calcium Carbonate has the minimum dielectric loss therefore it had the best insulating properties. The compression strength, young modulus, hardness decrease with filler content increase and PVC compound decreased. The maximum electrical permittivity in sample (3) compounded with 1.2 g of calcium carbonate and 4.8 g of PVC. Cost also can be reduced by the addition of filler material.
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Marjanovic, Milos, Dragana Dimitrijevic, Vesna Paunovic, and Zoran Prijic. "Microstructural and dielectrical characterization of Ho doped BaTiO3 ceramics." Serbian Journal of Electrical Engineering 11, no. 1 (2014): 35–46. http://dx.doi.org/10.2298/sjee131129004m.

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The Ho doped BaTiO3 ceramics, with different Ho2O3 content, ranging from 0.01 to 1.0 wt % Ho, were investigated regarding their microstructural and dielectric characteristics. Doped BaTiO3 were prepared using conventional solid state reaction and sintered at 1380?C for four hours. SEM analysis of Ho/BaTiO3 doped ceramics showed that the low doped samples exhibit mainly fairly uniform and homogeneous microstructure with the grain size ranged from 20-40 ?m. In the samples with the higher dopant concentration the abnormal grain growth is inhibited and the grain size ranged between 2-10 ?m. Measurements of dielectric properties were carried out as a function of temperature up to 180 ?C at different frequencies. The samples doped with 0.01wt % of Ho, exhibit the high value of dielectric permittivity (?r = 2160) at room temperature. A nearly flat permittivity-response was obtained in specimens with higher additive content. Using a Curie-Weiss law and modified Curie-Weiss law the Curie constant (C), Curie temperature (Tc) and a critical exponent of nonlinearity (g) were calculated. The Curie temperature of doped samples were ranged from 128 to 130?C. The Curie constant for all series of samples decrease with increase of dopant concentration and the lowest values were observed on samples doped with 0.01 wt % of holmium.
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Zhang, Yu, and Chuan Guo Ma. "Preparation and Electrical Properties of Aligned Carbon Nanotubes/Epoxy Resin Composites Induced by a Low Magnetic Field." Advanced Materials Research 189-193 (February 2011): 1340–43. http://dx.doi.org/10.4028/www.scientific.net/amr.189-193.1340.

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Aligned carbon nanotubes(CNTs)/epoxy resin(EP) composites were prepared under a low magnetic field (B<500mT) induction. The effect of different magnetic fields on the electrical and dielectrical properties of composites was investigated. The results show that the CNTs are aligned with rod-like aggregations instead of single CNTs when the magnetic field direction is vertical to the casting direction of samples, then electric conductivity, permittivity, dielectric loss of the composite are improved. And a larger magnetic field intensity and a bigger mould capacity can help the effect of magnetic field induction. However the CNTs are seriously aggregated and the electrical properties of composites change worse when the magnetic field direction is parallel to the casting direction of samples.
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Setrajcic, Jovan, Ljubisa Dzambas, and Stevan Armakovic. "Particularities in physical characteristics of molecular crystalline nanofilms." Zbornik Matice srpske za prirodne nauke, no. 119 (2010): 115–25. http://dx.doi.org/10.2298/zmspn1019115s.

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In this paper, the alterations and changes in dielectrical properties of different nanofilm molecular crystals, caused by the presence of boundaries were theoretically investigated and analyzed. By combined analytical and numerical calculations, allowed exciton states were found, and their spatial distribution along the axis limit (by layers of film) and the surface localization was examined. The relative permittivity of the observed ultrathin film was determined, and the impact of (five) boundary parameters on resonant absorption phenomenon: discrete (by frequencies) and selective (by layers of film) was examined. The conditions for the emergence of single-resonant absorption lines were found.
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Cao, Xian Peng, and Chong Guang Zang. "Study on Electromagnetic Properties of Ni-MWNTs Filling High Dielectrical EP Composites." Advanced Materials Research 706-708 (June 2013): 274–78. http://dx.doi.org/10.4028/www.scientific.net/amr.706-708.274.

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In this paper, we got Ni-MWNTs through pretreatment of MWNTs and electroless plating of nickel, and observed the Ni-MWNTs and MWNTs with TEM and FTIR. In addition, we prepared Ni-MWNTs/EP and MWNTs/EP composites. The volume resistivity、permittivity and permeability of composites were measured. Results showed that the volume resistivity of Ni-MWNTs/EP was higher than MWNTs/EP’s when volume fraction was lower than 8%. The ε" of Ni-MWNTs/EP was larger than MWNTs/EP’s. It indicated that Ni-MWNTs/EP had better electromagnetic energy storing and consumption capacity. And the permeability of Ni-MWNTs/EP would increase with the increasing of Ni-MWNTs. Ni-MWNTs/EP had some ferromagnetism.
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Ionete, Eusebiu Ilarian, Artur Visse, Radu Dorin Andrei, Mirela Irina Petreanu, Stefan Ionut Spiridon, and Roxana Elena Ionete. "Electrical and Dielectrical Properties of Composites Based on Alumina and Cyclic Olefin Copolymers." Materials 17, no. 21 (2024): 5349. http://dx.doi.org/10.3390/ma17215349.

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Understanding the performance of polymer dielectrics at different temperatures is becoming increasingly important due to the rapid development of electric cars, electromagnetic devices, and new energy production solutions. Cyclic olefin copolymers (COCs) are an attractive material due to their low water absorption, good electrical insulation, long-term stability of surface treatments, and resistance to a wide range of acids and solvents. This work focused on the dielectric and electrical properties of cyclic olefin copolymer (COC)/Al2O3 composites over a wide range of temperature and frequency domains, from room temperature to cryogenic temperatures (around 125 K). Permittivity, electrical conductivity, and electrical modulus are given consideration. A composite of up to 50% Al2O3 mixed with COC was prepared via a conventional melt-blending method. The final samples were formed in sheets and processed using injection and extrusion moldings. It was found that formulations with Al2O3 concentrations ranging from 10 to 50% resulted in higher electrical conductivity while maintaining the viscosity of the composite at a level acceptable for polymer-processing machinery. Our data show that COC/alumina composites present substantial potential as materials for high-frequency applications, even at the regime of cryogenic temperatures.
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Tsai, B., H. Xue, E. Birgersson, S. Ollmar, and U. Birgersson. "Dielectrical properties of living epidermis and dermis in the frequency range from 1 kHz to 1 MHz." Journal of Electrical Bioimpedance 10, no. 1 (2019): 14–23. http://dx.doi.org/10.2478/joeb-2019-0003.

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Abstract We determine the in-vivo dielectric properties—resistivity and relative permittivity—of living epidermis and dermis of human skin soaked with a physiological saline solution for one minute between 1 kHz and 1 MHz. This is done by fitting approximate analytical solutions of a mechanistic model for the transport of charges in these layers to a training set comprising impedance measurements at two depth settings on stripped skin on the volar forearm of 24 young subjects. Here, the depth settings are obtained by varying the voltage at a second inject on the electrical-impedance-spectroscopy probe. The model and the dielectric properties are validated with a test set for a third depth setting with overall good agreement. In addition, the means and standard deviations of the thicknesses of living epidermis and dermis are estimated from a literature review as 61±7 μm and 1.0±0.2 mm respectively. Furthermore, extensions to resolve the skin layers in more detail are suggested.
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Dzubenko, L. S., P. P. Gorbyk, A. A. Sapyanenko, and N. M. Rezanova. "The influence of carbon-containing, magnetic and nano-dispersed additions on structure and electrophysical properties of polypropylene-based composite monofibers." Surface 13(28) (December 30, 2021): 197–205. http://dx.doi.org/10.15407/surface.2021.13.197.

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There were PP- and iron-containing, fibrous, carbon- and nanodispersed-addition-based composite fibers prepared. There were addition content equals of 5.0%mass. There were blend of isotactic PP and addition homogenized in melt with one-screw lab extruder. There were zonal temperature on extruder equals of 230-250 o C. There were strangs receiving in bath of water and threated with knife granulation. Then, there were granules drying on air during 5h, and, then in thermal vacuum oven at 80±5 o C during 3h. Then, there are monofiber of 1 mm’s diameter formed on lab stand. Then, from one formed those others monofibers of different values of spinneret drawing (Фв, %). There were Фв for monofibers equals of 300 and 500%. Then, there were formed monofibers threated with thermoorientational drawing process at 150 oC. Then, there were monofibers of Фв value, which equals of 300%, drawn till draw degree λ=6, but, those others of Фв value, which equals of 500% - to λ=4. It is succeed, for composite monofibers, that orientational drawing process has had realized, until to the same value, as well as for one of virgin PP. But, when at formation and thermoorientational drawing processes, there were placing much number of breaks, as compared with monofiber of pure PP. When studying the structure with SEM technique, there was revealed microfibrillar structure of composite monofiber. When using optical microscopy, then there was determined irregularity for distribution of addition’s particles, leading to disproportional distribution of tension values at loading. It is revealed, for composite monofiber, at given value for content of addition, that electrical conductivity phenomenon is absent here. There are real ε’and imaginal ε’’ parts of complex dielectrical permittivity phenomenon, on frequency of 9 GHz, equals of 2.1 and 0.2, accordingly. It is established, that pure, non-drawn and composite monofiber itrinsically have satisfactory magnetic properties (σs=0.5 Gs∙cm3/g, Hc= 695 E). There are real μ’ and imaginal μ’’ parts of complex magnetical permittivity phenomenon equals of 1.1 and 0.02, accordingly.
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Kryszyn, Jacek, and Waldemar Smolik. "2D MODELLING OF A SENSOR FOR ELECTRICAL CAPACITANCE TOMOGRAPHY IN ECTSIM TOOLBOX." Informatics Control Measurement in Economy and Environment Protection 7, no. 1 (2017): 0. http://dx.doi.org/10.5604/01.3001.0010.4604.

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Electrical capacitance tomography is used to visualize a spatial distribution of dielectrical permittivity of materials placed in a tomographic sensor. An image is reconstructed from measurements of mutual capacitances of electrodes placed around the examined volume. This technique is characterized by very high temporal resolution – it is possible to achieve even few thousands of images per second. One of drawbacks of the method is low spatial resolution. Electrical capacitance tomography is mainly used in industry, e.g. for multiphase flow visualization. One of important elements of a tomographic system is a sensor which parameters influence quality of measurements and therefore affects quality of reconstructed images. In the Division of Nuclear and Medical Electronics a Matlab toolbox called ECTsim was developed. It is used for modelling of sensors, simulations of electrical field and image reconstruction. In this article we present the latest improvement which is modelling of a sensor using algebra of sets. Using primitive elements like rectangle and sector of a ring it is possible to perform operations like union, intersection and difference of two elements with a designed language. With such tools it is easy to prepare complex models of tomographic sensors which have different geometries. In this paper we show two models of sensors with different geometry in order to show how ECTsim solves forward problem.
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Dissertations / Theses on the topic "Dielectrical permittivity"

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Fromille, Samuel S. IV. "Novel Concept for High Dielectric Constant Composite Electrolyte Dielectrics." Thesis, Monterey, California. Naval Postgraduate School, 2013. http://hdl.handle.net/10945/53408.

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Approved for public release<br>This research was part of an ongoing program studying the concept of multi-material dielectrics (MMD) with dielectric constants much higher than homogenous materials. MMD described in this study have dielectric constants six orders of magnitude greater than the best single materials. This is achieved by mixing conductive particles with an insulating surface layer into a composite matrix phase composed of high surface area ceramic powder and aqueous electrolyte. Specifically examined in this study was micron-scale nickel powder treated in hydrogen peroxide (H2O2) loaded into high surface area alumina powder and aqueous boric acid solution. This new class of dielectric, composite electrolyte dielectrics (CED), is employed in an electrostatic capacitor configuration and demonstrated dielectric constant of order 10 [raised to the 10th power] at approximately 1 Volt. Additionally, it is demonstrated that treated nickel can be loaded in high volume fractions in the CED configuration. Prior studies of composite capacitors indicated a general limitation due to shorting. This results from the onset of percolation due to excess loading of conductive phases. Insulated particles described herein are successfully loaded up to 40% by volume, far above typical percolation thresholds. Simple models are presented to explain results.<br>Lieutenant, United States Navy
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Nicholls, Simon J. "High permittivity ceramics for dielectrically loaded applications." Thesis, University of Sheffield, 2017. http://etheses.whiterose.ac.uk/16354/.

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A temperature-stable, ultra-high permittivity dielectric ceramic, based on CTLNT, has been successfully fabricated at significantly reduced sintering temperatures with no deterioration of microwave properties, through the addition of a Bi_4B_2O_9 (BBO) sintering aid. This work has been an extension of previous findings where it was shown that 0.2CaTiO_3-0.8(Li_0.5Nd_0.5)TiO_3 (CTLNT) with 4wt% BBO as a liquid-phase sintering aid gives rise to exceptional microwave (MW) dielectric properties, (relative permittivity, ε_r = 127, quality factor, Qf_0 = 2700 GHz, and temperature coefficient of the resonant frequency, τ_f = +4 ppm/°C) at reduced sintering temperatures (1200°C). Prior to this, it has been exceptionally difficult to produce a large ε_r dielectric material, with both a low sintering temperature and near-zero temperature stability, without dramatic deterioration of the dielectric properties of the material. This contribution set out to investigate and understand the sintering mechanism between the CTLNT + xwt% BBO system, to aid in the development of designer sintering aids in the development of other microwave dielectric ceramic materials and devices. CTLNT + 1, 3, 4 and 5wt% BBO compositions were fabricated and a variety of analysis techniques were used, such as density, XRD, SEM, TEM, EDS and MW characterisation. Density increased with increasing BBO concentration and sintering temperature, and the MW results reflected the changes in density. The 1wt% BBO composition showed the greatest variation between the sintering temperatures, and 4wt% composition demonstrated optimum MW results of: ε_r=125, Qf_0=2518 GHz and τ_f=4 ppm/°C, at a sintering temperature of 1200°C. The variation of τ_f with changes in BBO concentration was non-linear, which suggested a chemical reaction was taking place. XRD results revealed no secondary phases, regardless of BBO concentration. SEM results showed increased crystal grain size as BBO concentration and sintering temperatures increased, as well as increased contrast variation on the polished surface and darker-contrast amorphous phase in the fracture surface. The contrast variation in the polished surfaces were also indicative of a chemical reaction. Using a combination of XRD, TEM and SEM it was demonstrated that highly polarisable Bi3+ ions entered the CTLNT perovskite lattice and locally increasing ε_r. The accompanying ex-solution of TiO2 precipitates, observed and analysed under SEM and TEM, as the BBO concentration increased implied the formation of Ti vacancies (V_Ti^'''') in the perovskite matrix to compensate for the extra positive charge of the Bi3+. The ex-solution of Ti indicates Bi3+ ions substitute onto the A-site of the perovskite crystal system for lower valence ionic elements, after the following generic defect equation: 4(A)_A^x+(Ti)_Ti^x⇒4(Bi)_A^∙+V_Ti^'''' The residual phase was found to be a boron-rich liquid-phase, which acted as the sintering aid, with a large negative τ_f which compensates for the positive τ_f of the CTLNT. The CTLST + xwt% BBO system (S = Sm) was then investigated to determine if a similar mechanism would occur. CTLST + 1, 2, 3 and 4wt% BBO compositions were fabricated and underwent the same analysis techniques. Density increased with increasing BBO concentration up to 1250°C, after which density fell for all samples; the 4wt% BBO composition exhibited the largest density, at 1250°C. The MW results reflected this trend, which saw a general increase in ε_r as BBO concentration and sintering temperature increased, which fell universally at 1300°C. 〖Qf〗_0 would generally increase with increased BBO concentration, across all sintering temperatures, while a dip was observed at 1250°C, and the 4wt% BBO composition demonstrated optimum properties of: ε_r = 105.7, Qf_0 = 3295 GHz and τ_f = -4 ppm/°C, sintered at 1200°C. Contrary to the CTLNT system, the variation of τ_f with BBO content and sintering temperature was linear. SEM reflected density changes, where crystal grain increased with increasing BBO concentration, up to 1250°C. At 1300°C, samples suffered from dissolution into the liquid-phase, increasing pore sizes, decreasing density and, thus, impacting on the MW properties of the samples. Similar to the CTLNT system, contrast variation was observed, in addition to darker B-rich liquid phase in the fracture surface. EDS from both SEM and TEM revealed that Bi was present within the CTLST matrix, however no TiO2 precipitates were observed. Large Zr contamination within CTLST is the likely cause of the difference in defect chemistry, as excess of Zr substitution onto the perovskite B-site compensates for Bi substitution onto the A-site, negating the need for TiO_2 precipitates to ex-solve. Multi-layer ceramic capacitors (MLCCs) of the CTLNT + 4wt% BBO composition were fabricated to determine whether the temperature stabilities of the material in conjunction with a large ε_r would allow the material to be a suitable candidate as a Class 1 C0G/NP0 MLCC device. Fabrication of the devices followed the conventional method, but required modification due to delamination. These modifications included: longer firing times to allow for binders and plasticisers to burn-out fully; calcined alumina powder base to fire and sinter samples upon, to avoid sticking issues; and solvent wetting of individual layers to adequately fuse layers together pre-firing and sintering. Successful MLCC devices had case sizes of EIA ‘2928’ and IEC ‘7472’. SEM and EDS revealed no mixing or exchange of materials between the dielectric and the platinum internal electrode, and generally good adhesion between both materials. Electrical tests revealed that, despite the temperature stability observed at 1-3 GHz in the MW study, that the MLCC devices would be classed as EIA “M8J” and IEC “P1000”, however maximum available test frequency of 1 MHZ is much lower than the average operating frequencies of class 1 devices, which lie between 100 MHz – 30 GHz.
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Waldron, Isaac James. "Ring Resonator Method for Dielectric Permittivity Measurements of Foams." Digital WPI, 2006. https://digitalcommons.wpi.edu/etd-theses/666.

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Dielectric permittivity measurements provide important input to engineering and scientific disciplines due to the effects of permittivity on the interactions between electromagnetic energy and materials. A novel ring resonator design is presented for the measurement of permittivity of low dielectric constant foams. A review of dielectric material properties and currently available measurement methods is included. Measurements of expanded polystyrene are reported and compared with results from the literature; good agreement between measurements and published results is shown.
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Duong, Danny. "The complex dielectric properties of aqueous ammonia from 2 GHz - 8.5 GHz in support of the NASA Juno mission." Thesis, Georgia Institute of Technology, 2011. http://hdl.handle.net/1853/42891.

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A new model for the complex dielectric constant, ε, of aqueous ammonia (NH4OH) has been developed based on laboratory measurements in the frequency range between 2-8.5 GHz for ammonia concentrations of 0-8.5 %NH3/volume and temperatures between 277-297 K. The new model has been validated for temperatures up to 313 K, but may be consistently extrapolated up to 475 K and ammonia concentrations up to 20 %NH3/volume. The model fits 60.26 % of all laboratory measurements within 2σ uncertainty. The new model is identical to the Meissner and Wentz (2004) model of the complex dielectric constant of pure water, but it contains a correction for dissolved ammonia. A description of the experimental setups, uncertainties associated with the laboratory measurements, the model fitting process, the new model, and its application to approximating jovian cloud opacity for NASA's Juno mission to Jupiter are provided.
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Xu, Yifan. "Studies on field effect transistors with conjugated polymer and high permittivity gate dielectrics using pulsed plasma polymerization." Connect to resource, 2005. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=osu1124219179.

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Thesis (Ph. D.)--Ohio State University, 2005.<br>Title from first page of PDF file. Document formatted into pages; contains xx, 187 p.; also includes graphics (some col.). Includes bibliographical references (p. 174-187). Available online via OhioLINK's ETD Center
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Umaña, Juan Antonio. "Measurement of complex dielectric permittivity of pavement materials." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1998. http://www.collectionscanada.ca/obj/s4/f2/dsk2/tape17/PQDD_0004/MQ32519.pdf.

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Marais, Johannes Izak Frederik. "A permittivity measurement system for high frequency laboratories." Thesis, Link to the online version, 2006. http://hdl.handle.net/10019/580.

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Ravindran, Ramasamy. "Deposition and characterization of high permittivity thin-film dielectrics." Diss., Columbia, Mo. : University of Missouri-Columbia, 2006. http://hdl.handle.net/10355/4530.

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Thesis (M.S.)--University of Missouri-Columbia, 2006.<br>The entire dissertation/thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file (which also appears in the research.pdf); a non-technical general description, or public abstract, appears in the public.pdf file. Title from title screen of research.pdf file (viewed on April 17, 2009) Includes bibliographical references.
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Sloma, A. "Complex dielectric permittivity of water, inorganic and organic solutions." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2000. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape4/PQDD_0019/MQ58086.pdf.

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Kahouli, Abdelkader. "Etude des propriétés physico-chimiques et (di-)électriques du parylène C en couche mince." Thesis, Grenoble, 2011. http://www.theses.fr/2011GRENT019.

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Ces travaux de thèse ont consisté à mener une étude approfondie des propriétés physico-chimiques duparylène C, qui est un polymère chloré, en lien avec ses propriétés électriques et diélectriques. Ces dernièresont cerné principalement le comportement de la constante diélectrique et des pertes diélectriques enfonction de la température (de l’azote jusqu’à 300 °C) sur une plage de fréquence étendue (10-4 Hz – 1 MHz).Les analyses par diffraction des rayons X ont montré que ce polymère présentait une structure cristalline a-monoclinique avec un taux de cristallinité de 45 % après élaboration. Ce taux est faiblement dépendant del’épaisseur pour des couches d’épaisseurs supérieures à 50 nm. Des recuits spécifiques appliqués sur leparylène C au dessus de la température de transition vitreuse ont permis de modifier le taux de cristallinité etdes valeurs de 30% à 75 % ont pu être obtenues. Une relation linéaire entre le taux de cristallinité et latempérature de recuit a été proposée. Les analyses diélectriques ont permis de mettre en évidence troismécanismes principaux de relaxation : La relaxation b, la relaxation g et la relaxation a. Par ailleurs, unmécanisme de polarisation interfaciale de type Maxwell-Wagner-Sillars (MWS) a été identifié à hautetempérature (au-delà de la transition vitreuse). La mobilité moléculaire des chaînes autour de la températurede transition vitreuse a été analysée en profondeur et les résultats (indice de fragilité, paramètresthermodynamiques…) ont été positionnés par rapport aux données de la littérature concernant d’autrespolymères<br>This work of thesis consisted in undertaking a thorough study of the physicochemical properties of theparylene C, which is a chlorinated polymer, in relationship with its electric and dielectric properties. These lastdetermined mainly the behavior of the permittivity and the dielectric losses according to the temperature (ofnitrogen up to 300 °C) on a wide frequency range (10-4Hz – 1 MHz). The analyses by x-rays diffraction showedthat this polymer had a a - monoclinical crystalline structure with a rate of crystallinity of 45 %. This rate isslightly depending on the thickness for layers thicknesses higher than 50 nm. Specific annealing applied to theparylene C made it possible to modify the rate of crystallinity and values from 30% to 75 % of crystallinitycould be obtained. A linear relation between the rate of crystallinity and the temperature of annealing wasproposed. The dielectric analyses made it possible to highlight three principal mechanisms of relaxation: b, g,a. In addition, a mechanism of interfacial polarization (Maxwell-Wagner-Sillars) was identified at hightemperature (beyond the glass transition). The molecular mobility of the chains around the glass transitionwas analyzed in-depth and the results (index of fragility, thermodynamic parameters...) were positionedcompared to the data of the literature concerning of other polymers
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Books on the topic "Dielectrical permittivity"

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Kar, Samares, ed. High Permittivity Gate Dielectric Materials. Springer Berlin Heidelberg, 2013. http://dx.doi.org/10.1007/978-3-642-36535-5.

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Kar, Samares. High Permittivity Gate Dielectric Materials. Springer Berlin Heidelberg, 2013.

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Saraband, K. Technique for measuring the dielectic constant of thin materials. National Aeronautics and Space Administration, 1988.

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Pampillón Arce, María Ángela. Growth of High Permittivity Dielectrics by High Pressure Sputtering from Metallic Targets. Springer International Publishing, 2017. http://dx.doi.org/10.1007/978-3-319-66607-5.

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Cravey, Robin L. W-band transmission measurements and X-band dielectric properties measurements for a radome material sample. National Aeronautics and Space Administration, Langley Research Center, 1997.

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Cravey, Robin L. W-band transmission measurements and X-band dielectric properties measurements for a radome material sample. National Aeronautics and Space Administration, Langley Research Center, 1997.

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Cravey, Robin L. W-band transmission measurements and X-band dielectric properties measurements for a radome material sample. National Aeronautics and Space Administration, Langley Research Center, 1997.

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L, Tiemsin Pacita, and Langley Research Center, eds. W-band transmission measurements and X-band dielectric properties measurements for a radome material sample. National Aeronautics and Space Administration, Langley Research Center, 1997.

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G, Geyer Richard, Janezic Michael D, and National Institute of Standards and Technology (U.S.), eds. The NIST 60-millimeter diameter cylindrical cavity resonator: Performance evaluation for permittivity measurements. U.S. Dept. of Commerce, Technical Administration, National Institute of Standards and Technology, 1993.

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G, Geyer Richard, Janezic Michael D, and National Institute of Standards and Technology (U.S.), eds. The NIST 60-millimeter diameter cylindrical cavity resonator: Performance evaluation for permittivity measurements. U.S. Dept. of Commerce, Technical Administration, National Institute of Standards and Technology, 1993.

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Book chapters on the topic "Dielectrical permittivity"

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Zydney, Andrew L. "Dielectric Permittivity." In Encyclopedia of Membranes. Springer Berlin Heidelberg, 2016. http://dx.doi.org/10.1007/978-3-662-44324-8_172.

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Zydney, Andrew. "Dielectric Permittivity." In Encyclopedia of Membranes. Springer Berlin Heidelberg, 2014. http://dx.doi.org/10.1007/978-3-642-40872-4_172-3.

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Kar, Samares. "Introduction to High-k Gate Stacks." In High Permittivity Gate Dielectric Materials. Springer Berlin Heidelberg, 2013. http://dx.doi.org/10.1007/978-3-642-36535-5_1.

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Toriumi, Akira, and Koji Kita. "Ternary HfO2 and La2O3 Based High-k Gate Dielectric Films for Advanced CMOS Applications." In High Permittivity Gate Dielectric Materials. Springer Berlin Heidelberg, 2013. http://dx.doi.org/10.1007/978-3-642-36535-5_10.

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Osten, H. Jörg. "Crystalline Oxides on Silicon." In High Permittivity Gate Dielectric Materials. Springer Berlin Heidelberg, 2013. http://dx.doi.org/10.1007/978-3-642-36535-5_11.

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Houssa, Michel, Peide Ye, and Marc Heyns. "High Mobility Channels." In High Permittivity Gate Dielectric Materials. Springer Berlin Heidelberg, 2013. http://dx.doi.org/10.1007/978-3-642-36535-5_12.

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Kar, Samares. "MOSFET: Basics, Characteristics, and Characterization." In High Permittivity Gate Dielectric Materials. Springer Berlin Heidelberg, 2013. http://dx.doi.org/10.1007/978-3-642-36535-5_2.

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Nishiyama, Akira. "Hafnium-Based Gate Dielectric Materials." In High Permittivity Gate Dielectric Materials. Springer Berlin Heidelberg, 2013. http://dx.doi.org/10.1007/978-3-642-36535-5_3.

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Niwa, Masaaki. "Hf-Based High-k Gate Dielectric Processing." In High Permittivity Gate Dielectric Materials. Springer Berlin Heidelberg, 2013. http://dx.doi.org/10.1007/978-3-642-36535-5_4.

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Schaeffer, Jamie K. "Metal Gate Electrodes." In High Permittivity Gate Dielectric Materials. Springer Berlin Heidelberg, 2013. http://dx.doi.org/10.1007/978-3-642-36535-5_5.

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Conference papers on the topic "Dielectrical permittivity"

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Anshin, Vitaly S., Alexey A. Politiko, Viktor A. Dyakonov, and Artem V. Pyzanov. "Syntactic Foams with Low Dielectric Permittivity." In 2024 IEEE 9th All-Russian Microwave Conference (RMC). IEEE, 2024. https://doi.org/10.1109/rmc62880.2024.10846829.

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Gäbler, Simone, Henning Heuer, Gert Heinrich, and Richard Kupke. "Quantitatively analyzing dielectrical properties of resins and mapping permittivity variations in CFRP with high-frequency eddy current device technology." In 41ST ANNUAL REVIEW OF PROGRESS IN QUANTITATIVE NONDESTRUCTIVE EVALUATION: Volume 34. AIP Publishing LLC, 2015. http://dx.doi.org/10.1063/1.4914628.

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Anderson, Barbara I., Frank Shray, James Hemingway, Eric Decoster, Peter R. Swinburne, and Scott J. Jacobsen. "Dielectric Inversion of LWD Propagation-Resistivity Tools for Formation Evaluation." In 2022 SPWLA 63rd Annual Symposium. Society of Petrophysicists and Well Log Analysts, 2022. http://dx.doi.org/10.30632/spwla-2022-0022.

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Oilfield exploration and production drilling companies commonly use Logging-While-Drilling (LWD) measurements provided by propagation-resistivity tools. These tools emit radio waves at frequencies from 400 kHz to 2 MHz and measure signal attenuation and phase shift between receiver pairs. In this frequency range, the measurements are sensitive to both the electric conductivity and dielectric permittivity in surrounding rock formations. Tool response to these two parameters has been characterized by modeling and is well known after many decades of study and analysis. However, dielectric permittivity as a formation parameter is still poorly understood. Over the frequency range in question, the permittivity shows considerable dispersion. The first-order effect of dispersion is to decrease as frequency increases. In addition, laboratory studies under controlled conditions have shown that several competing effects of grain-surface structure and metallic inclusion combine and distort the dielectric signature of the propagation-resistivity measurements. Also, fluid parameters can introduce surface effects. Clearly, there is no simple petrophysical answer to such a complex formation response. One way to analyze the problem is to directly invert the measured attenuation and phase shift data to obtain formation conductivity and permittivity. The inversion must be separately performed at each operating frequency to account for dispersion. The algorithm described in this paper was developed anew from previously published work by rederiving the solution from Maxwell’s equations in a more computationally efficient manner. The inversion provides independent conductivity/resistivity log curves and permittivity log curves. For quality control, the dielectrically inverted resistivity curves are compared to the conventionally processed phase-shift and attenuation resistivity curves. The dielectrically inverted resistivity will always fall between the two conventionally processed resistivities. There is no simple relationship between the dispersive, frequency dependent permittivity and any formation or fluid parameter, comparable to Archie’s simple water-saturation relationship. Both microscopic and macroscopic formation parameters contribute to dispersion: water-filled porosity, cation exchange capacity (CEC), conductive minerals, and formation factor. Past studies in research and in log interpretation have provided some insights on these reservoir property dependencies of permittivity in shaly sands. On the other hand, carbonate rocks with their widely varying pore structure impose additional uncertainties. Still, there appear some underlying common trends among many logs studied to date with dielectric inversion quantities. On the reservoir scale, dielectric measurements in general have proven to be a useful tool for estimating water saturation independently of water salinity. Dielectric inversion of LWD array propagation measurements provides this information at radial depths away from the borehole wall much deeper than the dedicated wireline GHz-pad tools. Thus, the water-saturation estimates from array tools may indicate hydrocarbons even in the presence of deeper invasion. The new dielectric-inversion algorithm accommodates any vendor’s axisymmetric LWD propagation-resistivity array tool that is featured in the SPWLA Resistivity-SIG catalogue. The dielectric inversion has been successfully applied to legacy logs. It applies equally well to real-time processing while drilling. It will hopefully fill a missing gap between raw tool measurements and true petrophysical interpretation.
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Azizoglu, Zulkuf, and Zoya Heidari. "Influence of Grain Size and Shape on the Performance of Dielectric Permittivity-Based Water Saturation Assessment Models." In 2023 SPWLA 64th Annual Symposium. Society of Petrophysicists and Well Log Analysts, 2023. http://dx.doi.org/10.30632/spwla-2023-0011.

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Dielectric permittivity mixture models commonly assume simple geometries for the constituting rock components, which affect their reliability in rocks with complex pore geometry and rock fabric such as carbonates. The combined influence of pore geometry, grain shape, and grain size on the performance of those models in water saturation assessment remains to be tested. Frequency-domain dielectric permittivity simulations can model the influence of pore and grain geometries on dielectric permittivity without a need for explicitly defining those parameters. Individual impacts of the aforementioned properties can be quantified and separated in the pore-scale domain via dielectric permittivity simulations. Therefore, the objectives of this paper are to (a) design pore-scale rock samples with different grain shapes and sizes, (b) investigate the influence of grain shape, grain size, and pore connectivity on the dielectric permittivity of the pore-scale rock samples as well as rock images from carbonate and sandstone formations, and (c) evaluate the performance of multiple dielectric permittivity mixture models in the quantification of water saturation. We construct three-dimensional (3D) synthetic rock models with spheroidal grains. We use different aspect ratios (i.e., the ratio of the radius of the major axis to the radius of the minor axis) and grain sizes for spheroids. Next, we numerically alter the water saturation. We perform frequency-domain dielectric permittivity simulations (through the solution of Maxwell’s equations in the frequency domain) in actual and synthetic samples in the frequency range of 100 Hz to 5 GHz. Finally, we test the performance of multiple dielectric permittivity mixture models (e.g., Maxwell-Garnett, Hanai-Bruggeman, CRIM, etc.) in the estimation of water saturation from dielectric permittivity measurements. We observed that the relative permittivity (i.e., the real part of the dielectric permittivity) increased with an increase in the aspect ratio of the spheroid grains. The electrical conductivity (which is associated with the imaginary part of the dielectric permittivity) decreased as the grains became flatter, which is due to the decreasing efficiency in electrical current flow. The dielectric permittivity dispersion is much less significant for rounder spheroid grains. The dispersion and absolute values of the relative permittivity and electrical conductivity decreased with the decreasing water saturation. We documented that overlooking the influence of pore and grain geometries can lead to average relative errors in water saturation up to 100% in the sandstone and carbonate samples. Taking into account the grain geometry and using Maxwell-Garnett formulation with the background medium properties estimated with the CRIM equation resulted in the lowest average relative errors (10%) in water saturation quantification. The documented results quantified the impacts of grain size, grain shape, and pore connectivity on dielectric permittivity. This analysis was possible through pore-scale modeling of dielectric permittivity dispersion. The outcomes demonstrate the limitations of the current dielectric permittivity mixture models in the calculation of dielectric permittivity and assessment of water saturation under different conditions. Therefore, the results of this work can help in quantifying the uncertainty associated with the use of existing dielectric permittivity mixture models depending on the pore and grain geometry of any given rock.
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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.

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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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Abdallah, Wael, Ahmad Al-Zoukani, and Shouxiang Ma. "Matrix Dielectric Permittivity for Enhanced Formation Evaluation." In SPE Middle East Oil & Gas Show and Conference. SPE, 2021. http://dx.doi.org/10.2118/204886-ms.

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Abstract Modern dielectric tools are often run to obtain fundamental formation properties, such as remaining oil saturation, water-filled porosity, and brine salinity. Techniques to extract more challenging reservoir petrophysical properties like Archie m and n parameters are also emerging. The accuracy and representativeness of the obtained petrophysical parameters depend on the input parameter accuracy, such as matrix permittivity. In carbonates, matrix permittivity is known to vary over a wide range, for example, limestone matrix permittivity reported in the literature ranges from 7.5 to 9.2. The main objective of the current study is to reduce matrix dielectric permittivity uncertainty for enhanced formation evaluation in carbonate reservoirs. All dielectric measurements were conducted on 1.5 in. carbonate plug samples by means of a coaxial reflection probe with a range of frequency between 10 MHz and 1 GHz. To calculate matrix mineral dielectric permittivity, sample porosity must be obtained. Stress-corrected helium porosity from routine core analysis is used and samples mineralogy and chemical composition are measured by X-Ray diffraction. Dielectric system calibration is done by utilizing several well-characterized standards with known dielectric properties. Calcite and dolomite matrix permittivity are assessed by laboratory measurements. Results of this study and based on data from 180 core plugs allowed to assess the validity of the defined errors by statistical analysis, resulting in much reduced uncertainties in carbonate rock matrix dielectric permittivity; thus enhancing formation evaluation using dielectric measurements. The current study provides better control on dielectric permittivity values used in dielectric log interpretation for limestone formations. Such knowledge will provide better confidence in interpreted data such as water-filled porosity, flushed zone salinity and water phase tortuosity.
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S. A., Varnakov, Suslov K.N., Yashchenko A.S., and Krivaltsevich S.V. "THE DIELECTRIC CHARACTERISTICS OF A LOAMY SOIL SAMPLE TAKEN ON THE SOUTHERN FOREST-STEPPE ZONE OF THE OMSK REGION." In Mechanical Science and Technology Update. Omsk State Technical University, 2022. http://dx.doi.org/10.25206/978-5-8149-3453-6-2022-124-129.

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The results of measurements of the complex permittivity of loamy soil samples over a wide frequency range are presented. The empirical data on the soil’s dielectric permittivity are compared with data calculation from Dobson models. It is shown, that use Dobson model for calculating dielectric permittivity leads to unreliable data. Shows the need for measurements of various types of soils for the development of correct soil dielectric model, especially at frequencies below 1 GHz model.
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Funk, James, Michael Myers, and Lori Hathon. "Dielectric Characterization of Surface Relaxivity." In 2023 SPWLA 64th Annual Symposium. Society of Petrophysicists and Well Log Analysts, 2023. http://dx.doi.org/10.30632/spwla-2023-0112.

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NMR and dielectric measurements provide unique petrophysical tools to probe the molecular dynamics of restricted geometries. Both techniques exhibit time-dependent relaxations sensitive to electromagnetic surface interactions and sensitivity to diffusion length scales in the case of NMR relaxation. However, diffusion rates typical for pore fluids limit the accessible length scales probed with NMR. Dielectric measurements provide additional length scale interactions and measurements that can be incorporated with conventional NMR. These clarify the relaxation time T1 and T2 size assignments typically represented by r1 and r2 surface relaxivity and define the lateral extent of the “fast diffusion limit.” Using protocols established with the coupled physics used in magnetic resonance electrical properties tomography (MREPT) for imaging dielectric properties of tissues, we adapt a dielectric permittivity differential length to area correlation based on Maxwell’s equations. An established staged differential effective medium model for matrix and vug dielectric dispersion and a dielectric-T2 mapping technique are used to evaluate the NMR relaxation, diffusion, and formation factors based on measured length scales from scanning electron microscope (SEM) images of the matrix and micro-CT images of the vug system. Correlated NMR and dielectric measurements during spontaneous brine imbibition provide an additional technique to address surface relaxivity by comparing changes in dielectric permittivity in parallel with characterized surface relaxation rates (T1S or T2S). Rates are compared with BPP model correlation times established through dry matrix high-frequency limit dielectric relaxation and T1 NMR dispersion based on comparative 2 MHz and 23 MHz T1 distributions. The dielectrically classified T2 distributions show good correlations with petrophysical properties and image-based size distributions. Modeled surface relaxivity in the matrix fraction falls within the expected range with vug values related to the overlap in the distributions. The technique uses the extensive dynamic mobile charge length scales from dielectric measurements (Maxwell-Wagner effect) to refine our interpretation of easily measured NMR multi-exponential response. Although based on carbonates with clay-free surface conductance, adaptation to scaled clastic dielectric dispersion measurements is proposed.
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Khodaparast, Payam, and Zoubeida Ounaies. "Preparation of TiO2 Polymer Nanodielectrics via a Solvent-Based Technique." In ASME 2010 Conference on Smart Materials, Adaptive Structures and Intelligent Systems. ASMEDC, 2010. http://dx.doi.org/10.1115/smasis2010-3883.

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The effect of adding surface-functionally treated TiO2 nanoparticles on dielectric properties of PVDF matrix was investigated. Porosity of the nanocomposite films showed to have an impact on dielectric permittivity results. Thermal annealing was proposed as an effective way to overcome the porosity problem. By combination of surface treatment of particles and thermal annealing of nanocomposite films, considerable enhancement in dielectric permittivity of TiO2-PVDF nanocomposites was achieved. The experimental results were far higher than theoretical values based on Maxwell model, indicating the presence of an active interphase with high dielectric constant in the system.
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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.

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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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Reports on the topic "Dielectrical permittivity"

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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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2

Pfeifer, M. C. Test plan for prototype dielectric permittivity sensor. Office of Scientific and Technical Information (OSTI), 1993. http://dx.doi.org/10.2172/10194574.

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Sullivan, J. P. Novel low-permittivity dielectrics for Si-based microelectronics. Office of Scientific and Technical Information (OSTI), 1997. http://dx.doi.org/10.2172/534493.

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Raengthon, Natthaphon. Cation vacancy defect in modified barium titanate ferroelectric ceramics. Chulalongkorn University, 2021. https://doi.org/10.58837/chula.res.2021.22.

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Development of advanced technologies for electronic applications, particularly aiming to increase energy efficiency and sustainability, are increasing in demand for regular usage. A majority of this development involves improvement of material's properties. Researcher has been continuously studied and developed new electronic material. Ferroelectric ceramic is one of many materials that is of interest, for example, lead-based (e.g. Pb(Mg₁/₃Nb₂/₃)O₃: PMN) and lead-free (e.g. Ba(Zr,Ti)O₃: BZT) materials. It is, however, known that the RoHS (Restriction of Hazardous Substances Directive) listed Lead (Pb) as one of the hazardous materials and is restricted for using in many electronic applications. Therefore, the development of lead-free materials has increased in attention and there is many more aspects of research to be explored. The electrical properties of relaxor ferroelectric ceramics, especially dielectric and ferroelectric behaviors, are improved from normal ferroelectric ceramic, which led to the usage of these materials in various applications such as capacitors and piezoelectric devices. A majority of researches focuses on fundamental understanding of relaxor behavior both experimentally and theoretically as well as device development based on these materials. In fabrication process, it is common to find defects in polycrystalline materials, which can be in a range of atomicscale to micro-scale. These defects play major roles in controlling electrical properties of the ceramics. In some applications, defects can be advantage as to improve the properties of the devices. On the other hand, properties of devices can be deteriorated by the present of defects leading to electrical fatigue and failure of devices under extreme conditions. It is, therefore, important to understand how cation vacancy defect affects electrical properties of modified barium titanate ferroelectric ceramics. The effect of Acation non-stoichiometry on the electrical properties of barium strontium titanate ceramics is an interesting topic of investigation. This study examined the stoichiometric, Ba-excess, Ba-deficient, Sr-excess and Sr-deficient compositions of (Ba₀.₈Sr₀.₂)Ti0₃ ceramics. A-cation non-stoichiometry of (Ba₀.₈₀Sr₀.₂₀)TiO₃ ceramics affected dielectric properties differently. The Ba- and Sr-excess compositions decreased dielectric constant at Tmax while still maintaining broad phase transition characteristics. In contrast, dielectric constant increased in the Ba- and Sr-deficient compositions. The characteristics of electrical conduction are different at high temperatures when Ba- and Sr-deficiency is introduced to the dielectrics. Ti⁴⁺ state for the Ba-deficient composition is maintained. However, Ti⁴⁺state partially changes to Ti³⁺ state, giving rise in the polaron hopping conduction process for Sr-deficient composition. Therefore, this study shows that minor deviation of A-cation from stoichiometry can induce a different conduction process while maintaining the dielectric permittivity characteristics.
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Walthert, Lorenz, Douglas R. Cobos, and Patrick Schleppi. Technical report. Equations for improving the accuracy of Decagon MPS-2 matric potential readings in dry soils. Swiss Federal Institute for Forest, Snow and Landscape Research, WSL, 2023. http://dx.doi.org/10.55419/wsl:33724.

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Soil matric potential quantifies water availability in soils. Low soil matric potentials are difficult to measure with most in situ techniques. This is also the case for the widely-used dielectric MPS-2 sensor. This probe determines matric potential indirectly from the measured water content in its porous sensor ceramics using dielectric permittivity as a proxy for water content. The accuracy of MPS-2 readings was analyzed in desiccation experiments using 13 soils with different texture and organic carbon content and a WP4C dewpoint potentiometer as reference instrument. Further, it was explored whether observed inaccuracies relate to sensor calibration, confounding dielectric effects, or the water release characteristics of the sensor ceramics. Above -1000 kPa, the MPS-2 readings were accurate in all tested soils with a mean deviation of 3% to the reference values. Below -1000 kPa, MPS-2 readings were increasingly higher than the reference in all tested soils, but the deviation from the reference depended on soil type. Poor factory calibration of the sensors, soil texture dependent differences of water flow at the soil-ceramic interface, and dielectric effects are supposed to be the main reasons for the low and soil-type-specific MPS-2 sensor accuracy in dry soils. Nevertheless, the high consistency of the MPS-2 readings allowed us to derive soil-type-specific equations to improve the accuracy of measurements to values as low as -4000 kPa. We recommend applying the equations to any MPS-2 readings below ~ -1000 kPa to obtain more reliable data and thus an improved insight into the role of soil water in ecosystems.
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Dippold, Marcel, Makrina A. Chairopoulou, Maximilian Drexler,, Michael Scheiber, and Holger Ruckdäschel. From vibrating molecules to a running shoe: connecting dielectric properties with process feedback in radio-frequency welding of TPU bead foams. Universidad de los Andes, 2024. https://doi.org/10.51573/andes.pps39.gs.pfm.1.

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Besides new material solutions, innovative processing technologies are key for working towards a more sustainable future for bead foam products. Compared to standard steam chest molding, innovative radio frequency (RF) welding shows great potential based on its direct energy input, which results in reduced energy consumption. Thus, the present study provides fundamental insights into the correlation of dielectric properties of expanded thermoplastic polyurethane (ETPU) bead foams with the processing behavior. Impedance spectroscopy is used to analyze the complex relative permittivity 𝜀𝜀!∗ of both polymer and respective beads. The dielectric properties of polymers are dictated by their molecular structure and hence resulting dipoles. Thus, significant dependency on temperature and frequency is observed due to changes in chain flexibility and therefore alignment with the oscillating electromagnetic field. As cellular structures, the introduction of a second air phase leads to generally attenuated values at equal trends. Within the RF process, changes, predominantly in the imaginary part of 𝜀𝜀!∗ from initial starting temperatures up to welding, are directly reflected in the power curve as process feedback. Furthermore, temperature evolution and derived heating rate within the bead foams demonstrate excellent conformity with previous results with minor deviations due to the thermal inertia of the fiber optic temperature sensor.
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Hou, Z., N. Terry, S. S. Hubbard, and B. Csatho. Entropy-Bayesian Inversion of Time-Lapse Tomographic GPR data for Monitoring Dielectric Permittivity and Soil Moisture Variations. Office of Scientific and Technical Information (OSTI), 2013. http://dx.doi.org/10.2172/1062597.

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8

Hou, Zhangshuan, Neil C. Terry, and Susan S. Hubbard. Entropy-Bayesian Inversion of Time-Lapse Tomographic GPR data for Monitoring Dielectric Permittivity and Soil Moisture Variations. Office of Scientific and Technical Information (OSTI), 2013. http://dx.doi.org/10.2172/1069207.

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