How the Telegraph and the Telephone Formed a Worldwide Wired Electromagnetic Environment

The principle of electromagnetic induction was independently discovered by Michael Faraday (England) and Joseph Henry (USA) in 1831–32. The momentous discovery gave birth to numerous inventions that made civilization “modern,” beginning with the telegraph. First the telegraph and then the telephone required the installation of millions of miles of electric wire to cross continents and oceans in order to function as a global telecommunications system. These wires created a wholly new, anthropogenic electromagnetic environment, whose frequencies were orders of magnitude greater than those occurring naturally. Its effects on human beings, particularly inside cities, and the biosphere generally were unknown. Even now, more than a century later, the medical and environmental effects of this worldwide wired infrastructure are at best but partially understood. The telecommunications revolutions of the mid- and late 19th century were eagerly anticipated and implemented swiftly on an unprecedented scale, creating the technological basis for worldwide instantaneous communication. This paper describes the key discoveries that created the scientific and technical breakthroughs that allowed the first telecommunications revolutions to take place.

Using machine learning to predict optimal electromagnetic induction instrument configurations for characterizing the shallow subsurface

Electromagnetic induction (EMI) is used widely for hydrological and other environmental studies. The apparent electrical conductivity (ECa), which can be mapped efficiently with EMI, correlates with a variety of important soil attributes. EMI instruments exist with several configurations of coil spacing, orientation, and height. There are general, rule-of-thumb guides to choose an optimal instrument configuration for a specific survey. The goal of this study was to provide a robust and efficient way to design this optimization task. In this investigation, we used machine learning (ML) as an efficient tool for interpolating among the results of many forward model runs. Specifically, we generated an ensemble of 100 000 EMI forward models representing the responses of many EMI configurations to a range of three-layer subsurface models. We split the results into training and testing subsets and trained a decision tree (DT) with gradient boosting (GB) to predict the subsurface properties (layer thicknesses and EC values). We further examined the value of prior knowledge that could limit the ranges of some of the soil model parameters. We made use of the intrinsic feature importance measures of machine learning algorithms to identify optimal EMI designs for specific subsurface parameters. The optimal designs identified using this approach agreed with those that are generally recognized as optimal by informed experts for standard survey goals, giving confidence in the ML-based approach. The approach also offered insight that would be difficult, if not impossible, to offer based on rule-of-thumb optimization. We contend that such ML-informed design approaches could be applied broadly to other survey design challenges.

Design of an electromagnetic induction steam generator device based on air source heat pump

Aiming at the current problems of coal-fired boilers and electromagnetic induction steam generators for environmental pollution and high energy consumption, this article combines air source heat pumps and electromagnetic induction heating technology, and at the same time carries out the structure of the condensate tank and electromagnetic induction steam generator. Redesign. Through trial production and experimentation of the prototype, the results show that compared with traditional coal-fired boilers and separate electromagnetic induction heating technology to generate steam, this device not only achieves energy saving and environmental protection, but also the stability of the steam outlet temperature and the amount of steam generated. Compared with the use of electromagnetic induction heating alone, it has increased by 20%. It can be seen that the use of air source heat pump’ electromagnetic induction heating technology to generate steam saves energy and increases the amount of steam generated.

Electromagnetic Induction Measurements for Investigating Soil Salinization Caused by Saline Reclaimed Water

This paper focused on the use of electromagnetic induction measurements in order to investigate soil salinization caused by irrigation with saline reclaimed water. An experimental activity was carried out during the growing season of tomato crop in order to evaluate expected soil salinization effects caused by different saline agro-industrial wastewaters used as irrigation sources. Soil electrical conductivity, strictly related to the soil salinity, has been monitored for three months by means of Electromagnetic Induction (EMI) measurements, and evident differences in the soil response have been observed. The study highlighted two aspects that can improve soil investigation due to the utilization of geophysical tools. First, EMI data can map large areas in a short period of time with an unprecedented level of detail by overcoming practical difficulties in order to massively sample soil. At the same time, repeated measurements over time allow updating real-time soil salinity maps by using accurate correlations with soil electrical conductivity. This application points out how integrated agro-geophysical research approaches can play a strategic role in agricultural saline water management in order to prevent soil salinization risks in medium to long-term periods.

Geophysical investigations of the Tabernacle (Yilki) Cemetery, Encounter Bay, South Australia

Geophysical investigations were undertaken using ground penetrating radar (GPR) and electromagnetic induction (EMI) at the Congregational Tabernacle (Yilke) Cemetery, Encounter Bay. These yielded 25 probable and 16 possible grave locations, identified due to the presence of adjacent stratigraphic breaks in the soil profile on multiple GPR lines. Two larger areas of disturbance were identified in the GPR survey and an additional area by the EMI survey which may represent possible locations of the former Congregational Church, founded by Reverend Ridgeway Newland in 1846. While the results show no direct evidence of coffins and approximately half of the site was inaccessible to GPR survey, the results show that the currently accepted number of burials for this site (29) is probably too low.

Application of Traction Power Supply for Metro Rail Transit Based on Electromagnetic Sensing Technology

With the gradual acceleration of modernization, metro projects have been opened for the development and construction of urban areas. How to ensure the smooth operation of subway project in public service has become the focus of urban public safety service research. In view of this content, this paper studies the subway field of urban rail transit operation and improves the public safety of urban rail transit operation. Firstly, the factors affecting the track traction power supply are analyzed, the anti-interference technology of ring array electromagnetic sensor is added, and the research scheme is formulated according to the track potential research standard to ensure the operation of the power supply system. Then, the electromagnetic sensor traction algorithm is used to detect the subway track power supply signal, and the working characteristics and advantages of single electromagnetic induction and double electromagnetic induction are analyzed. The experimental results show that compared with the traditional electromagnetic sensor power supply signal detection algorithm, the content of this paper can judge whether the power supply is normal according to electromagnetic induction, detect whether the subway traffic deviates from the track traction coordinates, and understand the size of the deviation from the track. It improves the efficiency of traction power supply detection, stabilizes the running track of subway traffic, and is conducive to the protection and development of urban public safety.