Two different approaches for georadar data processing. A case study in archaeologocal prospecting

Advanced GPR processing is applied to reconstruct burried archaeological structures at Axum (etiopia

GPR prospecting in a layered medium via microwave tomography

The tomographic approach appears to be a promising way to elaborate Ground Penetrating Radar (GPR) data in order to achieve quantitative information on the tested regions. In this paper, we apply a linearized tomographic approach to the reconstruction of dielectric objects embedded in a layered medium. The problem is tackled with reference to a two-dimensional geometry and scalar case when data are collected over a linear domain with finite extent. In particular, in order to increase the amount of independent available data, a multi-frequency/multi-view/ multi-static measurement configuration is considered. With reference to stepped-frequency radar, this means that for each working frequency and for each position of the transmitting antenna (moved along a linear domain), the electric field scattered by the buried targets is measured in several locations along the same linear domain. The proposed inversion approach is based on the Born approximation and a regularized solution is introduced by means of the Singular Value Decomposition (SVD). The problem of determining the optimal measurement configuration (in terms of number of frequencies and number of transmitting and receiving antennas) is also tackled by a numerical analysis relying on the Singular Value Decomposition (SVD). Numerical examples are provided to assess the effectiveness and robustness of the proposed approach against noise on data

GPR based soil electromagnetic parameters determination for subsurface imaging

Abstract. The problem of estimating the dielectric permittivity and the electric conductivity of the soil starting from GPR measurements is addressed. A new estimation procedure is proposed and checked against synthetic data generated by a FDTD forward solver. A two-dimensional geometry and a two-layered background medium are considered

Electromagnetic inversion for subsurface applications under the distorted Born approximation

The problem of reconstructing dielectric permittivity of a buried object from the knowledge of the scattered field is considered for a two-dimensional rectangular geometry at a fixed frequency. The linearization of the mathematical relationship between the dielectric permittivity function and the scattered field about a constant reference profile function and the approximation of actual internal field with the unperturbed field leads to the so-called Distorted Born Approximation. To analyze the limitations and capabilities of the linear inversion algorithms, we investigate the class of the retrievable profiles. This analysis makes it possible to point out that a very reduced number of independent data is available, so requiring to employ regularization techniques in order to perform in a reliable and stable way the linear inversions. In this paper we present a general algorithm consisting in a regularized Singular Value Decomposition of the matrix resulting from a discretization of the problem. Finally, numerical results of linear inversions are given

On the Combined Use of Ground Penetrating Radar and Crack Meter Sensors for Structural Monitoring: Application to the Historical Consoli Palace in Gubbio, Italy

The paper deals with joint use of non-invasive monitoring technologies and civil engineering analysis methods aimed at providing multi-sensing information about the structural health of historical and cultural assets. Specifically, linear variable displacement transducers (LVDT) and ground penetrating radar (GPR) are considered for monitoring a significant crack affecting the Consoli Palace in Gubbio, Italy, precisely one of the walls of the cross-hall leading to the Loggia. In this frame, LVDT is adopted to control horizontal amplitude variations of the crack, while GPR is applied to investigate the wall interior and to detect the occurrence of inner issues related to the visible appearance of the crack on the wall surface. The effectiveness of GPR surveys is improved by means of a microwave tomography-based data processing strategy. The main result is that there is a consistency between the monitoring outputs of LVDT, which allowed us to display the crack widening/contraction due to the seasonal temperature variations, and the fact that no significant changes of the geometry of the inner areas of the walls were observed by the GPR

Ground Penetrating Radar in Dam Monitoring: The Test Case of Acerenza (Southern Italy)

Nowadays, dam safety management is gaining great importance since it affects in a crucial way the monitoring and improvement of risky reservoirs, but this topic is very challenging since the dam safety requires long-term and time-continuous monitoring. In this framework, the exploitation of conventional geotechnical investigation methods often requires invasive actions in the inner of the structure to be investigated (destructiveness) and only provides punctual information for small volumes. On the contrary, the application of noninvasive sensing techniques makes it possible to investigate higher volumes without affecting the structure. In this paper we describe the application of GPR for the monitoring and diagnostics of one of the largest dams in the Basilicata region (Southern Italy). The investigation aims at detecting and localizing underground sandstone banks that are potential ways of flow of water below the dam. The manageability and the noninvasiveness of GPR have resulted in particularly suitable for this kind of application because the versatility of this geophysical method allows to investigate large areas with a good spatial resolution giving the possibility to detect the presence of inhomogeneities in the subsoil below the dam

A novel KCNQ3 mutation in familial epilepsy with focal seizures and intellectual disability

Mutations in the KCNQ2 gene encoding for voltage-gated potassium channel subunits have been found in patients affected with early-onset epilepsies with wide phenotypic expression, ranging from Benign Familial Neonatal Seizures (BFNS) to epileptic encephalopathy with cognitive impairment, drug resistance, and characteristic EEG and neuroradiological features. By contrast, only few KCNQ3 mutations have been rarely described, mostly in patients with typical BFNS. We report clinical, genetic, and functional data from a family in which early-onset epilepsy and neurocognitive deficits segregated with a novel mutations in KCNQ3 (c.989G>T; p.R330L). Electrophysiological studies in mammalian cells revealed that incorporation of KCNQ3 R330L mutant subunits impaired channel function, suggesting a pathogenetic role for such mutation. The degree of functional impairment of channels incorporating KCNQ3 R330L subunits was larger than that of channels carrying another KCNQ3 mutation affecting the same codon but leading to a different amino acid substitution (p.R330C), previously identified in two families with typical BFNS. These data suggest that mutations in KCNQ3, similarly to KCNQ2, can be found in patients with more severe phenotypes including intellectual disability, and that the degree of the functional impairment caused by mutations at position 330 in KCNQ3 may contribute to clinical disease severity

Analysis of three differential gpr systems for subsurface imaging

The goal of this work is to analyze and compare possibilities of imaging using differential antenna systems with receiving antennas displaced symmetrically with respect to the transmitting antenna along three orthogonal directions. To this end, synthetic radargrams are generated by the finite-difference time-domain forward solver for each measurement setup. After that a microwave tomographic approach is applied to process the scattered field differential data and to facilitate the comparison among these systems. As a result, it was obtained that the system with antennas displaced along the vertical axis is the only one capable to provide a reliable image regardless of the shape of the object. The performed studies have shown the prospects of such system application in the practical GPR problems.Цель работы состоит в том, чтобы проанализировать и сравнить визуализационные возможности дифференциальных конфигураций антенных систем, составленных из приемной антенны – передающей антенны – приемной антенны, в которых приемные антенны симмет-рично смещены относительно передающей антенны вдоль трех ортогональных направлений. Для этого выполнено FDTD-моделирование радарограмм для каждой измерительной конфигурации. Для обработки дифференциальных данных полей рассеяния и сравнения между системами использован метод микроволновой томографии. Установлено, что только система с вертикально разнесенными антеннами способна обеспечить наиболее реалистичное изображение независимо от формы исследуемого объекта. Проведенные исследования показали перспективность применения такой системы в практических задачах георадиолокационного зондирования.Мета роботи полягає у тому, щоб проаналізувати й порівняти візуалізаційні можливості диференційних конфігурацій антенних систем, що складаються з приймальної антени – передавальної антени – приймальної антени, у яких приймальні антени симетрично зміщені відносно передавальної антени вздовж трьох ортогональних напрямків. Для цього виконано FDTD-моделювання радарограмм для кожної вимірювальної конфігурації. Для обробки диференційних даних полів розсіювання та порівняння між системами використано метод мікрохвильової томографії. Встановлено, що тільки система з вертикально рознесеними антенами здатна забезпечити найбільш реалістичне зображення незалежно від форми досліджуваного об’єкта. Проведені дослідження показали перспективність застосування такої системи в практичних задачах георадіолокаційного зондування

Activation of Kv7 potassium channels inhibits intracellular Ca2+ increases triggered by TRPV1-mediated pain-inducing stimuli in F11 immortalized sensory neurons

Kv7.2-Kv7.5 channels mediate the M-current (IKM), a K+-selective current regulating neuronal excitability and representing an attractive target for pharmacological therapy against hyperexcitability diseases such as pain. Kv7 channels interact functionally with transient receptor potential vanilloid 1 (TRPV1) channels activated by endogenous and/or exogenous pain-inducing substances, such as bradykinin (BK) or capsaicin (CAP), respectively; however, whether Kv7 channels of specific molecular composition provide a dominant contribution in BK- or CAP-evoked responses is yet unknown. To this aim, Kv7 transcripts expression and function were assessed in F11 immortalized sensorial neurons, a cellular model widely used to assess nociceptive molecular mechanisms. In these cells, the effects of the pan-Kv7 activator retigabine were investigated, as well as the effects of ICA-27243 and (S)-1, two Kv7 activators acting preferentially on Kv7.2/Kv7.3 and Kv7.4/Kv7.5 channels, respectively, on BK- and CAP-induced changes in intracellular Ca2+ concentrations ([Ca2+]i). The results obtained revealed the expression of transcripts of all Kv7 genes, leading to an IKM-like current. Moreover, all tested Kv7 openers inhibited BK- and CAP-induced responses by a similar extent (~60%); at least for BK-induced Ca2+ responses, the potency of retigabine (IC50~1 µM) was higher than that of ICA-27243 (IC50~5 µM) and (S)-1 (IC50~7 µM). Altogether, these results suggest that IKM activation effectively counteracts the cellular processes triggered by TRPV1-mediated pain-inducing stimuli, and highlight a possible critical contribution of Kv7.4 subunits