Measured Dielectric Permittivity of Contaminated Sandy Soil at Microwave Frequency

Abdelgwad, Ahmad H.; Said, Tarek M.

doi:10.1590/2179-10742016v15i2591

Cited by 15 publications

(5 citation statements)

References 19 publications

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“…Os sedimentos, em algumas camadas em profundidade, eram contaminados por petróleo, o que pode ter alterado as propriedades dos sedimentos, resultando na resposta detectada (cf. ABDELGWAD & SAID, 2016). É comum a prática de consertar caminhões e carros na praça e, de fato, a equipe de Arqueologia necessitou solicitar a retirada de um trator e uma caçamba do local no início da pesquisa.…”

Section: Discussão De Resultadosunclassified

Geofísica arqueológica no ambiente da Arqueologia Urbana

Allen

Porsani

Poluha

2017

rsab

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A reforma e a requalificação de centros históricos -como construção, saneamento, pavimentação, entre outras -requerem que uma pesquisa arqueológica seja realizada antes de qualquer intervenção. Nesse contexto, busca-se um equilíbrio entre o que pode sofrer impactos negativos e o que deve ser estudado e preservado arqueologicamente, sempre buscando atender à necessidade do melhoramento dos locais públicos. O Largo da Igreja Nosso Senhor do Bonfim, Marechal Deodoro, Alagoas, ofereceu oportunidade de empregar o método geofísico GPR (Ground Penetrating Radar ou Georadar) para orientar escavações, identificar áreas para preservação e informar engenheiros civis sobre possíveis desafios para a execução do projeto civil. Os resultados foram interessantes, proporcionando um bom argumento para a incorporação de metodologias geofísicas em projetos de Arqueologia Urbana similares. Palavras-chave: GPR-Ground Penetrating Radar; Geofísica arqueológica; Arqueologia Urbana. ABSTRACTBrazilian urban renewal projects in historic districts require that archaeological research be conducted prior to any intervention, such as excavations for sanitation, construction, pavement, among others. In such a context, a balance must be struck between what might suffer impacts and what should be studied and preserved archaeologically, while attending the need to improve these public spaces. The Largo da Igreja Nosso Senhor do Bonfim, a public square dating to the early 17th century, offered the opportunity to use Ground Penetrating Radar to guide excavations, identify areas for preservation and to inform civil engineers of possible challenges for the project generally. The results were mixed, but provide a strong argument for the incorporation of geophysical methods in similar projects.

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Section: Discussão De Resultadosunclassified

Geofísica arqueológica no ambiente da Arqueologia Urbana

Allen

Porsani

Poluha

2017

rsab

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“…In this example, the same sand as in [22] was used, where values of ε textsubscriptr,est ≈ [2.7, 3.5] and σ = [0.27, 0.40] were estimated in the 3 to 6 GHz frequency band. As shown in [28], the value of these constitutive parameters tends to decay with frequency. A summary of the recovered constitutive parameters is shown in Table 1.…”

Section: Plastic Bottle Filled With Sandmentioning

confidence: 92%

A Synthetic Aperture Radar (SAR)-Based Technique for Microwave Imaging and Material Characterization

et al. 2018

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This contribution presents a simple and fast Synthetic Aperture Radar (SAR)-based technique for microwave imaging and material characterization from microwave measurements acquired in tomographic systems. SAR backpropagation is one of the simplest and fastest techniques for microwave imaging. However, in the case of heterogeneous objects and media, a priori information about the constitutive parameters (conductivity, permittivity) is needed for an accurate imaging. In some cases, a first guess of the constitutive parameters can be extracted from an uncorrected SAR image, and then the estimated parameters can be introduced in a second step to correct the SAR image. The main advantage of this methodology is that there is little or no need for a priori information about the object to be imaged. Besides, calculation time is not significantly increased with respect to conventional SAR, thus allowing real-time imaging capabilities. The methodology has been validated by means of measurements acquired in a cylindrical setup.

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“…It is generally believed that the real part of the dielectric constant of the coal rock matrix is between 1.6 and 2.5, and the imaginary part of the dielectric constant is between 0.05 and 0.2 [32]. The real and imaginary values of the dielectric water constant are much higher than those of the coal matrix, which are 80 and 9, respectively [33,34].…”

Section: Effect Of Solvent To Solute Mass Ratio On Dielectricmentioning

confidence: 99%

Enhancement of Coal Permeability Using Aqueous NaCl with Microwave Irradiation

Guan

Nan

et al. 2022

Geofluids

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Water in coal pores can generate strong steam explosions when treated with microwave irradiation. In order to improve the sensitivity of coal reservoirs to microwaves, we used varying concentrations of NaCl on the pore solution, which further increased the effect of microwaves on permeability enhancement. In our experiments, we selected 3 ratios of water content and 5 different concentrations of NaCl. The changes of coal water content and permeability before and after irradiation were compared. In addition, changes in coal surface temperature and internal thermal power were analyzed through thermal imaging and random sphere numerical modeling. Results showed that the increase of the proportion of solution mass and the ion concentration in the solution improved the overall dielectric properties of coal rock samples. After microwave irradiation, the average reduction rate of water content in coal rock samples increased with the increase of ion concentration in the solution. Both the average surface temperature of the coal rock samples and the average electromagnetic heating power gradually increased; this increases the temperature rise rate and maximum temperature of coal rock samples under the same irradiation time, which is conducive to better rapid accumulation of steam pressure, thereby improving the pore structure more effectively. Finally, the maximum growth rate of permeability reached 466.18%. This work provides a novel train of thought to enhance coal permeability by using microwave irradiation.

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Measured Dielectric Permittivity of Contaminated Sandy Soil at Microwave Frequency

Cited by 15 publications

References 19 publications

Geofísica arqueológica no ambiente da Arqueologia Urbana

Geofísica arqueológica no ambiente da Arqueologia Urbana

A Synthetic Aperture Radar (SAR)-Based Technique for Microwave Imaging and Material Characterization

Enhancement of Coal Permeability Using Aqueous NaCl with Microwave Irradiation

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