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Time-domain solutions of Maxwell's equations in homogeneous and isotropic media are paramount to studying transient or broadband phenomena. However, analytical solutions are generally unavailable for practical applications, while numerical solutions are computationally intensive and require significant memory. Semi-analytical solutions (e.g., series expansion), such as those provided by the current theoretical framework of the multipole expansion, can be discouraging for practical case studies. This paper shows how sophisticated mathematical tools standard in modern physics can be leveraged to find semi-analytical solutions for arbitrary localized time-varying current distributions thanks to the novel time-domain Cartesian multipole expansion. We present the theory, apply it to a concrete application involving the imaging of an intricate current distribution, verify our results with an existing analytical approach, and compare the proposed method to a finite-difference time-domain numerical simulation. Thanks to the concept of current "pixels" introduced in this paper, we derive time-domain semi-analytical solutions of Maxwell's equations for arbitrary planar geometries. [ABSTRACT FROM AUTHOR]

The early time high altitude electromagnetic pulse conducted environment calculation is revisited by using the transmission line (TL) theory and including high-frequency corrections that were not present in the earlier studies. Waveform salient parameters, such as the current peak, rise time, and pulsewidth, are studied as a function of a number of parameters involved in the calculation. The obtained cumulative distribution functions of the parameter probabilities are discussed and compared with the existing standards for the HEMP protection. The high-frequency correction to the TL model results in a decrease of the current amplitudes of 15–20%. For the highest currents, rise times in the range of 25 ns are obtained. A less significant impact was found in the calculation of the pulsewidth, which was increased to about 150 ns. [ABSTRACT FROM AUTHOR]

In order to clarify the link between 40Ar/39Ar record in white mica and deformation, we performed in situ and bulkwise 40Ar/39Ar dating over the East Tenda Shear Zone (Tenda massif, Alpine Corsica). White micas from 11 samples were selected and extensively analyzed using in situ techniques across nested scales of strain‐intensity gradients developed at the expense of a late‐Variscan protolith. 40Ar/39Ar systematics are unaffected by inherited Ar and directly linked to deformation with little or no Ar lattice (volume) diffusion. Extensive sampling allows constraining the end of deformation related to burial and exhumation, respectively, at ~34 and ~22 Ma, bracketing the duration of regional extensional shear to ~12 Myr. Results also highlight a regional strain localization toward the upper contact of the unit with smaller‐scale localization in specific lithologies, notably meta‐aplites. Second‐order complications exist, such as local ill‐defined correlations between ages and finite‐strain microstructures. Thus, the use of a strain gradient as a proxy for strain localization in time is regionally valid but sometimes locally too complex to track or resolve strain partitioning/localization trends at the meter (outcrop) scale and below. Age mixing and incomplete isotopic homogenization by dissolution/precipitation are identified as the main causes of local discrepancies that complicate the link between age and microstructure and the derivation of strain localization rates. Tracking temporal trends in shear distribution across regional‐scale deformation gradients in such settings is possible but requires a multi‐scale approach as implemented here to reveal younging patterns associated to strain localization. Key Points: Data are interpretable in terms of age‐deformation relationships and capture a broad‐scale localization of strain in time and spaceAt smaller scale, relating age with structures is more difficult because of greater complexity in 40Ar/39Ar systematicsThe shear zone has a duration of ~12 Myr during exhumation and deformation ended in the upper part of the viscous/brittle transition [ABSTRACT FROM AUTHOR]

In this paper, a model to analyze the propagation of intentional electromagnetic interferences disturbances along penetrating conductors into concrete walls is proposed. The model is based on the transmission line theory and considers the attenuation of the signal as a function of the water content of the concrete, the thickness of the wall, and the frequency of the signal. The model is validated with experiments performed with a vector network analyzer and a time-domain reflectometer. A numerical parametric study is performed in order to quantify the expected attenuation levels of a concrete wall with different water content levels. The simulation results show that the peak amplitudes of the disturbance can be significantly attenuated for both dry and wet concrete. [ABSTRACT FROM PUBLISHER]

Summary: Both district heating and solar collector systems have been known and implemented for many years. However, the combination of the two, with solar collectors supplying heat to the district heating network, is relatively new, and no comprehensive review of scientific publications on this topic could be found. Thus, this paper summarizes the literature available on solar district heating and presents the state of the art and real experiences in this field. Given the lack of a generally accepted convention on the classification of solar district heating systems, this paper distinguishes centralized and decentralized solar district heating as well as block heating. For the different technologies, the paper describes commonly adopted control strategies, system configurations, types of installation, and integration. Real‐world examples are also given to provide a more detailed insight into how solar thermal technology can be integrated with district heating. Solar thermal technology combined with thermally driven chillers to provide cooling for cooling networks is also included in this paper. In order for a technology to spread successfully, not only technical but also economic issues need to be tackled. Hence, the paper identifies and describes different types of ownership and financing schemes currently used in this field. [ABSTRACT FROM AUTHOR]

Abstract: Zircon U‐Pb geochronology is a very robust dating method but the accuracy of determined ages can sometimes be compromised. This is because, as commonly observed, the U‐Pb isotope system can be reopened during the post‐crystallization evolution of a zircon. The present manuscript investigates the capability of traverses by LA‐ICP‐MS to identify zones of well‐preserved U‐Pb isotope systematics within zircon crystals. The data for the different zones can be used to construct internal Discordia lines that provide age information about crystallization and metamorphism of single zircon crystals. To test our approach, we analyzed zircons from three ca. 3.96 Ga Acasta gneisses. Results demonstrate that such a method allows retrieval of original crystallization age in most of the studied zircons, even in those that experienced ancient U‐Pb disturbances resulting in discordant U‐Pb data. It was also possible to estimate disturbance ages, though not as precisely as for the igneous crystallization, in many of the studied crystals. [ABSTRACT FROM AUTHOR]

This paper reports the results of two experimental campaigns aimed at studying the high-frequency response of a raceway containing low voltage power, telephone, and Ethernet cables, to external electromagnetic field illumination. The raceway was tested against HPEM transients inside a gigahertz transverse electromagnetic (GTEM) cell and low-power fields inside a reverberation chamber (RC). The high-power electromagnetic (HPEM) tests revealed that the low-voltage power cables have the greatest coupling under a hyperband illumination, compared to telephone and Ethernet cables. The RC tests allowed the determination of statistical transfer functions from random incident field configurations into DM voltage in cable loads. The responses were found to be governed by the raceway under test at the lower frequencies (below 1 GHz). Between 0.2 and 1 GHz, the raceway gives about 10 dB higher coupling than a short patch cable. The difference is even greater at lower frequencies and for shielded cables. In the frequency band 1–3 GHz, little difference was observed between short patch cables and the full raceway, but both were still significantly higher than direct coupling to the measurement card. Beyond 3 GHz, the coupling is clearly dominated by the terminal equipment. The experiments performed in this paper provide a better understanding of the expected induced voltages and currents in commercial cable systems when exposed to intentional electromagnetic interference (IEMI)-like signals. [ABSTRACT FROM PUBLISHER]

Hardware implementation of artificial neural networks (ANNs) allows exploiting the inherent parallelism of these systems. Nevertheless, they require a large amount of resources in terms of area and power dissipation. Recently, Reservoir Computing (RC) has arisen as a strategic technique to design recurrent neural networks (RNNs) with simple learning capabilities. In this work, we show a new approach to implement RC systems with digital gates. The proposed method is based on the use of probabilistic computing concepts to reduce the hardware required to implement different arithmetic operations. The result is the development of a highly functional system with low hardware resources. The presented methodology is applied to chaotic time-series forecasting. [ABSTRACT FROM AUTHOR]

In this paper, we present general considerations for the application of the multiconductor transmission-line theory for simulating shielded spacecraft harness cable assemblies. Some of the practical issues that occur in the modeling process of various components of cable assemblies in spacecraft applications, namely connectors, pigtails, and backshells are discussed. The overall transfer impedance of the assembly measured through a current injection with a pseudomicrostrip line is used as a figure of merit to evaluate the total shielding provided by the harness. Some of the parameters of the model were available from the manufacturers’ datasheets, while others were determined either experimentally or empirically. The position of the cables along the cross section was randomly assigned by the simulation tool. In general, the obtained simulation results are found to be in reasonable agreement with the experimental data. It is found that the generally overlooked contact impedances between the cable shields and connectors play a significant role, especially at low frequencies. The presented simulation results also emphasize the importance of the inductance and resistance of the connector backshell interconnection to the spacecraft chassis. [ABSTRACT FROM AUTHOR]

In this letter, we propose a formula for evaluating the transfer impedance of two-layer braided cable shields. The proposed formula results from the combination of the model proposed by Vance for the evaluation of the equivalent transfer impedance of a two-layer braided shield and the improved Kley model for the transfer impedance of single-layer braided shields. [ABSTRACT FROM PUBLISHER]

Acute telogen effluvium ( ATE) is often associated with female androgenetic alopecia ( FAA), but predictive factors of ATE- FAA association and clinical factors or therapies that may influence the progression of ATE to chronic telogen effluvium ( CTE) have not been reported. We have identified predictive factors of ATE- FAA association and retrospectively evaluated the impact of therapies on the progression to CTE. Conclusions are as follows: (i) Triggering cause is a significant independent factor that predicts association of ATE with FAA. (ii) Triggering causes with higher risk of concurrent FAA are severe diet, iron deficiency, and thyroid dysfunction. (iii) Patients suffering ATE may benefit from different therapeutic approaches (depending on which is the triggering cause) to prevent or treat the association with FAA. (iv) Minoxidil use shows a trend to lower the percentage of progression to CTE. (v) Apart from treating the precipitating cause, the different additional oral treatments used have not shown any correlation with progression to CTE. [ABSTRACT FROM AUTHOR]

We present a review and comparison of different models representing the frequency dependence of the soil electrical parameters (conductivity and permittivity). These models are expressed in terms of curve-fit expressions for the soil conductivity and relative permittivity, which are based on experimental data. Six available models/expressions are discussed and compared making reference to two sets of experimental data. It is shown that the soil models by Scott, Smith–Longmire, Messier, and Visacro–Alipio predict overall similar results, which are in reasonable agreement with both sets of experimental data. Differences between the soil models are found to be more significant at high frequencies and for low-resistivity soils. The causality of the considered models is tested using the Kramers–Kronig relationships. It is shown that the models/expressions of Smith–Longmire, Messier, and Portela satisfy the Kramers–Kronig relationships and thus provide causal results. The soil models are applied to the analysis of grounding systems subject to a lightning current. A full-wave computational model is adopted for the analysis. The analysis is performed considering two cases: 1) a simple horizontal grounding electrode, and 2) a realistic grounding system of a wind turbine. Two current waveforms associated with typical first and subsequent return strokes are adopted for the representation of the incident lightning current. In agreement with recent studies, simulations show that the frequency dependence of the soil parameters results in a decrease of the potential of the grounding electrode, with respect to the case where the parameters are assumed to be constant. It is found that the models/expressions by Scott, Smith–Longmire, Messier, and Visacro–Alipio predict similar levels of decrease, which vary from about 2% (\rhoLF = 20 Ω·m and first stroke) up to 45% (\rhoLF = 10 000 Ω·m and subsequent stroke). On the other hand, the models of Portela and Visacro–Portela predict significantly larger levels of the decrease, especially for very high resistivity soils. Furthermore, in the case of a high resistivity soil (10 000 Ω·m), the Visacro–Alipio expression predicts a longer risetime for the grounding potential rise, compared to the predictions of Scott, Smith–Longmire, and Messier models. [ABSTRACT FROM PUBLISHER]

The cascaded transmission line theory of Paul and McKnight is used in this paper to predict near-end crosstalk (NEXT) and far-end crosstalk (FEXT) in a bundle of twisted wire pairs. The approach is validated using the CST Cable Studio commercial software and experimental data. NEXT and FEXT along twisted pair bundles are then evaluated using a pure deterministic approach for the electromagnetic coupling while taking into account the random distribution of victim and aggressor pairs in the bundle. The results obtained using the presented approach are compared with available simplified empirical expressions (ANSI/FSAN). It is shown that the simplified expressions are able to predict the overall trend of the power sum loss. However, they do not always provide the worst case values. The presented theory can find important applications in the design of data transmission systems for which accurate crosstalk modeling is a vital task. It can be used for example as a replacement for the experiments in obtaining the parameters of simplified models for NEXT and FEXT. [ABSTRACT FROM PUBLISHER]

We present an analysis of the thermal response of a hot-wire electroexplosive device (EED) excited with different transient signals. First-order and second-order analytical models to calculate the thermal response of an EED are assessed taking as reference numerical simulations obtained using ANSYS. For the early-time response, when the time is much smaller than the thermal constant of the EED, the best approach corresponds to a first-order differential model in which the thermal capacitance is calculated with short-pulse excitations. A linear simplification to calculate the maximum temperature due to short excitations is also shown to be adequate. On the other hand, the most appropriate model for the late-time response is a second-order model. The models are used to assess the electromagnetic susceptibility of a wired EED for different electromagnetic pulsed environments. Radiated signals produced by a mesoband radiator, two types of radars, and a hyperband radiator are considered. The radar signal proved to be the most disturbing source because of its highest duty cycle and its flat spectral response around a specific frequency. Even the temperature firing threshold can be exceeded with the radiated field produced by a radar of 200 kW of output power located at a distance of 5 m. [ABSTRACT FROM PUBLISHER]

This paper describes the simulation, design, realization, and experimental test of a tapered transmission line (TL) for adapting a broad-band impulse generator to a radiating antenna, for a frequency range of 50 MHz–1 GHz. Two different taper geometries are considered and discussed in the analysis: exponential and logarithmic. Two analysis methods are also used: 1) analytical equations obtained by applying the TL theory and 2) full-wave numerical simulations in both frequency and time domains using Comsol. It is shown that, in general, an exponential taper performs better than a logarithmic one, particularly at high frequencies. Time-domain simulations reveal that, for fast transient subnanosecond pulses, both tapers can be used equivalently and the signal does not suffer from any significant distortion while traveling along the tapers. We also show that analytical equations obtained using the TL theory are in very good agreement with full-wave simulation results and can be used advantageously in the design of tapers. This paper also presents the mechanical design and the realization of an exponential taper used for the connection of a 50-\Omega pulser to a half-impulse radiating antenna (HIRA) having an input impedance of 100-\Omega . The realized taper is fully characterized in the frequency domain using a vector analyzer and in the time domain using a reflectometer and shown to be performing in agreement with the simulations. [ABSTRACT FROM PUBLISHER]