Ground Resistance of Buried Metallic Parts in Urban Areas: an Extensive Measurement Campaign

In urban and industrial areas, a relevant presence of buried metallic objects (e.g., gas and water pipes, etc.) can be detected. Usually, these elements are imagined as widespread meshed metallic grids in a good contact with the soil. In the last years, an arising interest on their role in the identification of a global earthing system has been expressed by the scientific community. Unfortunately, the geometrical and electrical properties of this kind of buried metallic parts cannot be provided by any documentations. This is mostly due to the fact that no trustworthy schemes are provided, as the management of these metallic parts is responsibility of different companies, which have installed them during several years. In order to characterize the buried metallic elements with reference to the electrical safety issue, the main quantity of interest is their resistance to earth. With this aim, a field measurement campaign was organized and the resistance to earth of more than 800 metallic objects has been evaluated through a simplified measurement protocol. In this paper, the measurement protocol, the setup, the results, and their analysis are reported

Global Earthing System: Can Buried Metallic Structures Significantly Modify the Ground Potential Profile?

Global earthing systems (GESs), which are created by the interconnection of local earthing systems, should guarantee the absence of dangerous touch voltages. According to international standards, one of the reasons for this safety characteristic of GESs is that medium-voltage and low-voltage grounding systems form a quasi-equipotential area. Typical examples of GESs are in city centers due to the high number of interconnected grounding systems in the area. For this reason, in addition to ground grids, other metallic parts with different primary functions shall be also considered, e.g., water and gas pipes, tramway tracks, and building foundations can modify the electric potential distribution in the area. In this paper, a model based on the Maxwell's subareas method (MaSM) is used to evaluate how buried metallic parts, which are not intentionally connected to ground grids, modify the electric potential on the soil surface. First, the MaSM model is validated with experimental measurements on a simple electrode configuration. The measured voltages are compared with the MaSM results and with the results obtained with a finite-element method model simulated with COMSOL Multiphysics. Then, the simulations are carried out on a realistic urban test case

Validation and verification of modular GNC by means of TAS-I robot management framework in outdoor rovers exploration facility

The objective of STEPS2 “Rover Surface Navigation” work package was the design, development, validation and verification of innovative solutions suitable for the future (manned and unmanned) space robotics mission. A particular focus has been put in the autonomous capabilities to be implemented for the baseline mission scenario: sample canister acquisition and return, simulated in TAS-I ROvers eXploration facilitY.This paper gives an overview of the adopted System Development Life Cycle, that is based on V-model and agile methodologies. Then the infrastructure, including the ROXY facility and research robots are detailed. The paper focuses on the Test activities and relevant results for the Modular GNC developed on the TAS-I Robot Management Framework architecture. Finally, the future envisaged activities are presented, including upgrades to Methodology, ROXY facility and GNC modules and their usage in the frame of TAS-I research activities and ESA funded contracts

Autonomous Underwater Intervention: Experimental Results of the MARIS Project

open11noopenSimetti, E. ;Wanderlingh, F. ;Torelli, S. ;Bibuli, M. ;Odetti, A. ;Bruzzone, G. ; Lodi Rizzini, D. ;Aleotti, J. ;Palli, G. ;Moriello, L. ;Scarcia, U.Simetti, E.; Wanderlingh, F.; Torelli, S.; Bibuli, M.; Odetti, Angelo; Bruzzone, G.; Lodi Rizzini, D.; Aleotti, J.; Palli, G.; Moriello, L.; Scarcia, U

Rapid clinical management of leishmaniasis in emergency department: a case report with clinical review of recent literature

Systemic or localized lympho-adenomegaly is a common cause of access to the emergency department (ED), and differential diagnosis is often complicated. The combination of anamnesis, physical examination, laboratory tests, and instrumental diagnosis are extremely important to orientate toward a rapid and correct therapy, even if a prompt discrimination of the etiology of this lymphadenomegaly is not often possible. Our aim with this review is to improve the management of a dierential diagnosis between hematological and infective diseases as leishmaniasis in ED and suggest quick diagnostic techniques that might be useful for early identification. Together in the review, we describe a case report of a young man aected from visceral leishmaniasis who presented to our ED and was incorrectly addressed to the wrong ward for the study of his condition. Subsequently, we focus on the clinical presentation of visceral leishmaniasis and compare it to the most common dierential diagnoses that are usually taken into account in the management of such patients

Identification of point mutations and large intragenic deletions in Fanconi anemia using next-generation sequencing technology

Fanconi anemia (FA) is a rare bone marrow failure disorder characterized by clinical and genetic heterogeneity with at least 17 genes involved, which make molecular diagnosis complex and time-consuming. Since next-generation sequencing technologies could greatly improve the genetic testing in FA, we sequenced DNA samples with known and unknown mutant alleles using the Ion PGMTM system (IPGM). The molecular target of 74.2 kb in size covered 96% of the FA-coding exons and their flanking regions. Quality control testing revealed high coverage. Comparing the IPGM and Sanger sequencing output of FANCA, FANCC, and FANCG we found no false-positive and a few false-negative variants, which led to high sensitivity (95.58%) and specificity (100%) at least for these two most frequently mutated genes. The analysis also identified novel mutant alleles, including those in rare complementation groups FANCF and FANCL. Moreover, quantitative evaluation allowed us to characterize large intragenic deletions of FANCA and FANCD2, suggesting that IPGM is suitable for identification of not only point mutations but also copy number variations

Influence of LV Neutral Grounding on Global Earthing Systems

International Standards define a Global Earthing System as an earthing net created interconnecting local Earthing Systems (generally through the shield of MV cables and/or bare buried conductors). In Italy, the regulatory authority for electricity and gas requires distributors to guarantee the electrical continuity of LV neutral conductor. This requirement has led to the standard practice of realizing “reinforcement groundings” along the LV neutral conductor path and at users' delivery cabinet. Moreover, in urban high-load scenarios (prime candidates to be part of a Global Earthing System), it is common that LV distribution scheme creates, through neutral conductors, an effective connection between grounding systems of MV/LV substations, modifying Global Earthing System consistency. The aim of this paper is to evaluate the effect, in terms of electrical safety, of the aforementioned LV neutral distribution scheme when an MV-side fault to ground occurs. For this purpose, simulations are carried out on a realistic urban test case and suitable evaluation indexes are proposed

Influence of LV Neutral Grounding on Global Earthing Systems

International Standards define a Global Earthing System as an earthing net created interconnecting local Earthing Systems (generally through the shield of MV cables and/or bare buried conductors). In Italy the Regulatory Authority for Electricity and Gas requires Distributors to guarantee the electrical continuity of LV neutral conductor. This requirement has led to the standard practice of realizing “reinforcement groundings” along the LV neutral conductor path and at users’ delivery cabinet. Moreover, in urban high load scenarios (prime candidates to be part of a Global Earthing System), it is common that LV distribution scheme creates, trough neutral conductors, an effective connection between grounding systems of MV/LV substations, modifying Global Earthing System consistency. Aim of this paper is to evaluate the effect, in terms of electrical safety, of the above mentioned LV neutral distribution scheme when an MV-side fault to ground occurs. At this purpose simulations are carried out on a realistic urban test case and suitable evaluation indexes are proposed

A Practical Method to Test the Safety of HV/MV Substation Grounding System

The adequacy of a Grounding System (GS) to the safety conditions has to be periodically tested by measurements. The test methods and techniques used to verify the electrical characteristics of the GS include the measurements of step and touch voltages. The goal of the test is to verify that touch voltage and step voltage remain below a safe value in all the zones of the installation. The measurements can present some operational difficulties. The purpose of this paper is to present the procedure, step-by-step, of a practical method of measuring touch/step voltages in grounding systems located in urban or industrial areas with reduced accessibility. The suggested method uses auxiliary current electrodes located at short distances. This paper demonstrates by test measurements done in a real case that the method provides conservative results