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Low voltage shielded cable serves critical roles in controlling and measuring advanced power systems to ensure their reliability and safety. As a consequence, monitoring of the cable is significant, yet conventional monitoring techniques are limited for non-operating power systems for safety causes which eventually affects the reliability of the power system and brings economical loss. In this paper, a contactless signal communication approach via inductive coupler is applied to stepped frequency waveform reflectometry (SFWR) for monitoring operating power systems. Additionally, a long short-term memory (LSTM) based neural network model is adapted for compensating non-linear distortion of the signals yielded by the couplers. Compared to conventional approaches, LSTM has advantages to restore non-linearities of the couplers since it can respond to various non-linear factors such as the dimension of the coupler, the length of the cable, or the position of the signal application. The proposed reflectometry system for monitoring live shielded cable is tested on 75m 2-core shielded cable with two cases of fault emulation, and the efficacy of the proposed technique in real fields is also verified.

In recent years, the development of electronic devices are trending to be smaller and lighter, the techniques for suppressing electromagnetic (EM) radiation need to comply with these trends. EM shields are widely used to suppress EM radiation from transmission lines. EM shield for interconnection cable such as flexible-printed-circuits (FPC) requires flexibility of shielding-material. Consequently, EM shield becomes much more thin metallic shield and may be implemented near the transmission lines in the future. However, frequency response of the transmission coefficients of the shielded-FPC has dispersion due to insufficient shielding performance for near magnetic field. Elucidating the relationship between dispersion of frequency response and time response of transmission characteristics of shielded-FPC turns to be an important indicator of shielding techniques. In this paper, experimental extraction has been proposed for detailed investigating the frequency dispersion of shielded-FPC by using the RLGC equivalent-circuit model. The experimental extraction method used S-parameters measured by using vector network analyzer. The unnecessary components such as connectors are compensated correctly by using proposed method. The frequency response of primary and secondary parameters extracted using the proposed method reproduces all the dispersion characteristics of shielded-FPC successfully. More importantly, quantitative evaluation using the RLGC equivalent-circuit model considering dispersion characteristics can be performed experimentally.

Due to the electrical, thermal, and mechanical stress, the insulating materials of cable undergo a slow aging process in service, which leads to the decline of insulation performance. Besides, friction frequently occurs when the cable is moving or vibrating, which will easily cause mechanical damage including frays and chafes. Both aging and damage will cause the characteristic impedance to change. Therefore, it is of great significance for the safe operation of the cable to analyze the variations of characteristic impedance and to make an effective diagnosis. In this paper, a two-dimensional model of the cable containing defects is firstly built, and the characteristic impedance of the model is calculated by the finite element method (FEM). Meanwhile, a quantitative analysis of the characteristic impedance under two defect types is carried out. Secondly, combining the space-time focusing of time-reversal and the time-frequency characteristics of reflectometry, the time-reversal time-frequency domain reflectometry (TRTFDR) is proposed to diagnose the cable faults. Based on the distributed parameters calculated by the FEM, the TRTFDR simulation model is established to study the judgment of different faults. Finally, the validity of this method is verified by experiments.

High field intensity electromagnetic radiation effect test is difficult to simulate in large-scale space, and the existing bulk current injection (BCI) technology has a limited application of the nonlinear system test. Starting from the coupling mechanism of shielded wire, an analysis model about the response of the equipment under test (EUT) is built-in radiation and injection conditions. In addition, the equivalent corresponding relationship originates between the injected excitation source voltage and the radiation field intensity. The basis for obtaining the source of the injection excitation and performing extrapolation tests is found, and the test method of BCI replacing high field intensity electromagnetic radiation is developed. Subsequently, the passing-through load and communication station tests are performed to verify the theoretical derivation and the test method. As indicated from the research results, the BCI is capable of accurately replacing the high field electromagnetic radiation effect test of the EUT, and the maximum test error reaches 2.7 dB, capable of satisfying the actual needs of the project.

This study systematically investigated the influence of the position and inclination angle of an externally mounted hollow cathode in 1.35 kW magnetically shielded Hall thrusters to establish the r...

Magnetoencephalography (MEG) is highly sensitive to even a small amount of magnetic noise, and thus, a high-performance mag-netically shielded room (MSR) is essential. The shielding effect of a novel MSR should be predicted to verify whether it satisfies the required specifications of the MEG at the design stage. Therefore, an accurate prediction method based on the properties of shielding materials and the shape of the MSR is necessary. In this paper, we proposed a prediction method using a simple formula and permeability measured against very small magnetic field fluctuations. Using a ring-shaped test piece, permeability was measured against a very small magnetic field corresponding to the Rayleigh region, and the initial permeability and Rayleigh constant were estimated to determine the permeability calculated by the formula. The magnetic field generated inside the material was estimated by magnetic analysis, and it was confirmed that the permeability of the Rayleigh region should be used in the formula. To verify the prediction accuracy, we examined a simple example of a cylindrical shell by comparing the calculated results with the experimental results. It was confirmed that the pro-posed method is more accurate than the conventional method using the value of μ at 4 mA/cm.

This article develops an innovative model of shielded cable illuminated by high power electromagnetic pulse based on the tensorial analysis of network. The succinct model under study is competent in quick analysis of the radiated immunity (RI) and signal integrity (SI) considering skew, unbalanced impedance, and other nonideal factors for high-speed application. A Kron's topology graph describing coupling relation among ports of shielded cable is established. The Kron–Branin (KB) general metric of the unbalanced multiconductor cable RI and SI problem is formulated afterward. A 2 m twinax cable over a ground plane is calculated using KB model and the results agree well with the SPICE model and the simulation of CST. Skew, mixed-mode S-parameters variation, and radiation immunity with respect to various typical unbalanced factors are analyzed. The computational efficiency of KB model is compared with the SPICE model and CST. This inventive model provides system designers with a fast calculation tool in frequency domain for performance evaluation of long cable in a harsh electromagnetic environment.

An efficient multiconductor transmission line (MTL) model of a shielded twisted wire pair (TWP) with apertures on its sheath is developed for predicting common mode (CM) and differential mode (DM) currents induced in the shielded TWP cable. Its transfer impedance and admittance with one-line apertures on its sheath are derived in a closed form. Therefore, the MTL equations are formulated and solved to obtain the CM and DM currents induced in the shielded TWP. Moreover, the proposed MTL model is generalized to be applicable for the braided–shielded TWP, in which the transfer impedance and admittance are formulated analytically. Results showed that the induced DM current inside the braided–shielded TWP is suppressed dramatically due to the uniform structure of the cable. The models are validated by comparing their results with those obtained by the commercial software FEKO; good agreements are obtained.

In industrial applications, copper wire is often used in the cable core or the motor armature. These copper wires are made by passing copper rods through the round-hole mold in a wire drawing machine. To reduce friction, it is necessary to use a lubricant mixed with oil and water for lubrication. The oil would be consumed over time, so it is required to add oil in a while to maintain lubrication. Generally, concentration sensors are used to monitor the concentration of lubricant to determine the timing of replenishing the oil. The principle of the sensor is by the intensity change of optical reflection to detect the concentration. However, copper chips scraped off from the wire during the drawing process will gradually accumulate on the surface of the sensor, thus causing sensor misdetection due to the shading of the light source. In this paper, an improved concentration sensing system is proposed to solve this problem. In the proposed system, a clean water tank is placed beside the oil tank, and the sensor is located in the clean water tank most of the time and is moved to the oil tank for measurement only at a specific time. After the measurement is completed, it will return to the clean water tank. This can greatly reduce the time the sensor is immersed in the oil tank, minimizing the chance that the sensor is shielded by copper scraps. To enable the sensor to move in this manner, a novel linkage design is proposed to meet several requirements in the movement of the mechanism. The mechanism is featured by its simple structure and only one driving device is needed. Furthermore, motion analyses of the mechanism are provided. Finally, we explain the working principle of the measurement system where the proposed linkage and the concentration sensing system are combined. To sum up the results, the proposed method can effectively expand the frequency of on-site maintenance from monthly to annual, which greatly reduces manpower requirements and effectively improves stability.

MSR (magnetically shielded room) is one of the most effective methods of shielding the magnetic field of the environment. The design of a cuboid enclosed magnetic shielding room (MSR), which mainly made up of permalloy and aluminum, is optimized by an electromagnetic simulation software called ANSYS Maxwell. And the effects of the magnetic shielding room's parameters on the shielding effectiveness (SE) are studied. As far as we know, the presented results show that SE is inversely proportional to the size of the shielding space, but proportional to the thickness of each layer, and the interval between two layers exists an optimal value. An equivalent circuit model demonstrates the corresponding interpretations of the above results.

This article presents a protection method for controller area network (CAN) communication against electromagnetic interference (EMI) caused by switched-mode power supplies (SMPSs). SMPSs generate EMI noise on the communication lines by switching the power semiconductor devices, which often causes communication failure. Conventional EMI reduction methods, such as EMI filters and shielded cables, generally reduce the converter conducted noise and the noise susceptibility of the communication system. However, depending on the system configuration, these EMI reduction methods are not sufficient to prevent communication failure. To resolve this issue, the authors propose an EMI failure protection method that realizes robust CAN operation. The proposed method eliminates the coincidence between induced noise in the communication lines and the CAN sample timing so that no communication failure occurs. Experimental results verify that the proposed method is effective in interference reduction, and the proposed method is revised for resolving the converter output disturbance due to an undesirable shift of switching timing.

Unconventional folded shielded coplanar waveguide (FS-CPW) has yet to be fully investigated for tunable dielectrics-based applications. This work formulates designs of FS-CPW based on liquid crystals (LC) for electrically controlled 0-360˚ phase shifters, featuring a minimally redundant approach for reducing the LC volume and hence the costs for mass production. The design exhibits a few conceptual features that make it stand apart from others, noteworthy, the dual-strip structure with a simplified enclosure engraved that enables LC volume sharing between adjacent core lines. Insertion loss reduction by 0.77 dB and LC volume reduction by 1.62% per device are reported at 77 GHz, as compared with those of the conventional single-strip configuration. Based on the proof-of-concept results obtained for the novel dual-strip FS-CPW proposed, this work provides a springboard for follow-up investible propositions that will underpin the development of a phased array demonstrator.

The impact of gamma radiation on a commercial off the shelf microcontroller board has been investigated. Three different tests have been performed to ascertain the radiation tolerance of the device from a nuclear decommissioning deployment perspective. The first test analyses the effect of radiation on the output voltage of the on-board voltage regulator during irradiation. The second test evaluated the effect of gamma radiation on the voltage characteristics of analogue and digital inputs and outputs. The final test analyses the functionality of the microcontroller when using an external, shielded voltage regulator instead of the on-board voltage regulator. The results suggest that a series of latch-ups occurs in the microcontroller during irradiation, causing increased current drain which can damage the voltage regulator if it does not have short-circuit protection. The analogue to digital conversion functionality appears to be more sensitive to gamma radiation than digital and analogue output functionality. Using an external, shielded voltage regulator can prove beneficial when used for certain applications. The collected data suggests that detaching the voltage regulator can extend the lifespan of the platform up to approximately 350 Gy.

This article presents a hybrid finite-difference time-domain–simulation program with integrated circuit emphasis (FDTD–SPICE) method for analyzing the system-level coupling responses of the wireless communication system with antenna, metallic enclosures, braided shielded cable, and lumped element, when illuminated by an external electromagnetic pulse (EMP). In the hybrid method, a system-level SPICE model combining antenna and braided coaxial cable is proposed to predict the coupling effects including front-door and back-door couplings. FDTD is used to calculate the induced current on the outer conductor of the coaxial cable, which is then incorporated into the system-level SPICE model as an additional current source. Because the hybrid method avoids meshing the antenna and cable, it has higher computational efficiency than full-wave analysis. A typical microstrip antenna system is selected as a case to demonstrate the accuracy and effectiveness of this proposed method by comparing the numerical results with those obtained by CST. Then, considering the influence of the incident conditions of external EMP, the coupling voltages of the microstrip antenna system are calculated. Furthermore, a typical filter circuit is analyzed to illustrate the practicability of the proposed method. The obtained coupling response information demonstrate that the proposed method is available for designing electromagnetic protection of the inner circuits of the wireless communication system against the impact of external incident wave.

In this letter, a novel 4 b multistate frequency-selective surface is proposed. Four p-i-n diodes are used to maneuver multifunction behavior of the structure with seven different functional states. The 4 b binary state operations 0000, 1100, 0011, and 1111 offer transverse electric (TE)/transverse magnetic (TM) waves both transmit, TE transmit/TM shield, TM transmit/TE shield, and TE/TM both shield, respectively, at 2 GHz frequency. The passband at 2 GHz frequency has $-\text{10}$ dB fractional bandwidth of 117%. The binary states 1101 and 1110 are symmetric, which select the TE wave transmit/TM wave shield to the passband at 3.45 GHz frequency with $-\text{10}$ dB fractional bandwidth of 49%, whereas binary states 1011 and 0111 allow the TM wave to transmit at 3.45 GHz and shield the TE wave. The four symmetric binary states 0101, 0110, 1010, and 1001 provide transmission band at 3.45 GHz frequency for dual-polarized plane wave incidence. The transmission of both the passbands can be shielded by selecting the binary state equal to 1111. An equal circuit model is used to elaborate the contribution of different passive structural elements in terms of lumped components. A prototype of the structure is fabricated, and transmission coefficients for different states at normal and oblique incidence of the electromagnetic plane wave are measured, which verifies the simulated responses of the structure.

Longitudinal barriers are considered as passive safety systems designed to shield hazards located at roadsides against motor vehicle impacts. Since these barriers are manmade obstacles, they also pose a threat to drivers using the road. Recent motorcyclist accidents with longitudinal barriers have proven that a particular barrier successfully protecting vehicle occupants may wound or kill motorcyclists due to its components. For this reason, sharp and blunt edges in steel longitudinal barrier parts, such as posts are usually shielded against contact from unprotected motorcyclists during a high-speed impact event. In recent years, more longitudinal barriers have been designed with motorcyclists in mind and these motorcycle protection barriers have become wide spread especially on urban high-speed roads. However, since the development of these barriers are fairly new compared to conventional longitudinal barriers, there is limited guidance on their design criteria, such as thickness, geometry, connections. For this purpose, this paper intends to provide an artificial neural network metamodeling-based design optimization methodology to an existing continuous motorcycle protection barrier design to make it more competitive in terms of weight and thus, cost. As a result of this study, the optimized barrier has become 34% more economical compared to its original design while its protection level remained intact.

The microstructure evolution, mechanical properties, and tribological properties of deposited metal Fe-C-Cr-Ti-B alloy by self-shielded flux-cored wire electrode (FCAW S) with the introduction of exothermic addition and without it are investigated. Experimental studies showed that the introduction of CuO Al exothermic addition in the composition of the wire core filler reduced the grain size of the deposited metal. Furthermore, X-ray diffraction analyses show that the boride layer contained FeB, Fe2B, and Ti(C, N) phases. Depth-sensing indentation was used to determine hard phase properties (hardness, Young's modulus and plasticity coefficient). It was shown that introduction of CuO –Al exothermic addition in the core filer increased the mechanical properties of deposited metal. The latter can be explained by the grain size decrease, as well as a change in the phase composition of the deposited metal due to additional copper alloying. This transformation is accompanied by an increase in hardness and in the Young's modulus. Tribological tests showed the effectiveness of introduction of the exothermic addition CuO –Al into the filler core for increasing the wear resistance under conditions of 3-body abrasive particle wear.

In this paper it has been demonstrated that a shielded channel made by varying the side gate length in silicon-on-nothing junctionless transistor not only improves the short channel effect but also improve the performance of CMOS circuits of this device. The proposed device shielded channel dual gate stack silicon on nothing junctionless transistor (SCDGSSONJLT) drain induced barrier lowering (DIBL), cut-off frequency and subthreshold slope are improved by 20%, 39% and 20% respectively over the single material gate silicon on insulator junctionless transistor (SMG SOI JLT). The proposed device CMOS inverter fall time Tf (pS) and noise margin improves by 50% and 10% compare to shielded channel silicon on insulator junctionless transistor (SCSOIJLT). It has been observed that circuit simulation of CMOS inverter, NAND and NOR of proposed device. The static power dissipation in the case of proposed SCDGSSONJLT device are reduced by 45%, 81% and 83% respectively over the SMGSOIJLT. Thus, significant improvement in DIBL, cut-off frequency, propagation delay and static power dissipation at low power supply voltage shows that the proposed device is more suitable for low power CMOS circuits.

The synthesis of molecular cages consisting of fully fused, π-conjugated rings is rare due to synthetic challenges including preorganization, large strain, and poor solubility. Herein, we report such an example in which a tris-2-aminobenzophenone precursor undergoes acid-mediated self-condensation to form a truncated tetrahedron, one of the 13 Archimedean solids. Formation of eight-membered [1,5]diazocine rings provides preorganization and releases the strain while still maintains weak π-conjugation of the backbone. Thorough characterizations were performed by X-ray, NMR, and UV-vis analysis, assisted by theoretical calculations. The cage exhibits a rigid backbone structure with a well-defined cavity that confines a magnetically shielded environment. The solvent molecule, o-dichlorobenzene, is precisely encapsulated in the cavity at a 1:1 ratio with multiple π···π, C-H···π, and halogen···π interactions with the cage skeleton, implying its template effect for the cage closing reaction. Our synthetic strategy opens the opportunity to access more complex, fully fused, three-dimensional π-conjugated cages.

In this paper, the shielded open-circuited probe operating in the wide frequency range from 75MHz to 2GHz is proposed. The probe is made of an SubMiniature version A (SMA) flange connector. The central rod of the SMA connector emerges from a coaxial transition in the flange and shielded by four rods. The robe design allows us to calculate of the probe reflection coefficient S11 used simple analytical transmission line model (TEM wave mode), the parameters of which were calibrated on a set of substances with a known frequency spectrum of permittivity. The refractive index (RI) and normalized attenuation coefficient (NAC) retrieval technique is based on solving the inverse problem of minimizing the residual norm between measured and calculated frequency spectra of reflection coefficient S11. After calibration, the root-mean-square error (determination coefficient) between the measured and calculated module and phase of the reflection coefficient S11 for the sets of calibration media air, distilled water, butanol, pure ice, water solution with NaCl of salinity of 8.9% do not exceed 0.26dB (0.995) and 0.03 rad (0.999), respectively, in the frequency range from 75MHz to 2GHz. The root-mean-square error (determination coefficient) between the measured RI and NAC spectra for four soil cover samples (variation of the clay fraction from 10.5 g/g to 47.6 g/g) using the proposed probe and a precision coaxial cell not exceeds 0.109 (0.993) and 0.057 (0.986), respectively, in the frequency range from 75 MHz to 2 GHz. As a result, it is experimentally shown that RI и NAC can be measured by the proposed non-precision probe with an error comparable to the precision coaxial cell.

The electromagnetic interference (EMI) problems are crucial for system-in-package (SiP) due to the high demand of miniaturization and dense integration. Shielding methods are generally employed to protect SiP from EMI, through assessing the key performance index, i.e., shielding effectiveness (SE). In this article, the SE of a SiP is evaluated by using near-field scanning method. The SEs derived by using maximum near-field values and average near-field values are comparatively analyzed. The difference in near-field patterns of the unshielded and shielded SiPs may incur overestimation of the SE by using maximum field values. Both simulation and measurement results manifest that the gap between SiP and printed circuit board (PCB) will significantly change the radiation pattern of a shielded SiP, and thus has a great impact on the SE, especially when the frequency is above 1 GHz. However, a good correlation is found between the SE based on average near-field and the SE derived from the radiated power. This study has revealed the near-field shielding properties of SiP, which is helpful for building and analyzing the correlation among the SEs measured by different methods, including the near-field scanning, transverse electromagnetic (TEM) cell and reverberation chamber.

A prototype persistent current switch is developed for an actively shielded whole-body 1.5 T MRI magnet having an operating current of ∼500 A. The switch is developed using a six-strand CuNi-NbTi conductor. The total length of the conductor used in the PCS is ∼40 m using a bifilar winding technique having a room temperature resistance of 15 Ω and an inductance of 6.6 μH. Two numbers of thermo-foil heaters having a resistance of 90 Ω each are placed between the layers of the winding pack of the switch. The wet-winding technique is followed for the switch using a cryogenic grade epoxy. The characteristics of the switch are performed using a 4 K test rig for its applicability in the 1.5 T MRI magnet. The normal resistance of the switch is measured to be 12.5 Ω at 15 K which is 15% less than the estimated value. The total energy loss onto the switch is estimated to be 0.24% of the ramping energy of the magnet at 6 V charging voltage. The thermal switching profile of the switch is studied and correlated with the total energy loss.

The conventional definition of shielding effectiveness (SE) is well suited for calculations of far-field electromagnetic shielding. However, in the near field, SE calculations are not as straightforward. In radio-frequency interference (RFI) problems, the majority of field coupling occurs in the near field. Thus, a well-defined method for calculating the near-field SE is needed to estimate the suppression of RFI achieved by shielding cans. In this study, a method based on near-field scanning is developed to extract the SE of board-level shielding cans. The SE is defined by modeling the shielded noise source as equivalent dipole moments. The accuracy of the equivalent source is analyzed via the least-square error and correlation coefficient as confidence verification parameters. By applying the reciprocity theorem, the voltage coupled on a planar inverted F antenna from an unshielded and a shielded source is calculated. The coupled voltage from a shielded noise source serves as a reference to validate the effectiveness of the proposed method. Practical shielding cans were used to develop and validate the SE extraction method using full-wave 3D simulations and measurements.

This work presents the design and fabrication of a novel uniplanar microstrip patch antenna that is simultaneously dual-band and dual-polarized. By embedding a carefully designed metamaterial-based electromagnetic bandgap structure (MTM-EBG) into the edges of a conventional square patch, operation with orthogonal linear polarizations at both 3.6 and 5.8 GHz is achieved. The design is fully printed, compact, low-profile, and pin-fed using a shielded microstrip configuration, and it is 17% smaller than a conventional square patch at the lower operating frequency. The presented antenna shows a reflection coefficient better than −16 dB at each frequency and over 24 dB of port-to-port isolation. Radiation patterns are patch-like in both operating bands, with broadside gains of 6.4 and 5.3 dBi at the lower and higher operating frequencies, respectively. The antenna is fabricated using conventional PCB manufacturing methods, and measurement results are in very good agreement with simulations.

This study is dedicated to the development of a new design of the shielded low-loss metal-dielectric waveguide for the frequency range of 90–100 GHz. High level of losses in metal is a major challenge complicating implementation of commonly used waveguides in the specified wavelength range. The study objective was to develop the proposal regarding the waveguide design with losses lower than 0.5 dB/m, with persistent wave polarisation. To address the problem, we analysed various waveguide design solutions and estimated losses per unit length along with the possibility to implement the proposed design. We proposed the final variant of waveguide design and selected parameters of structural members to solve the problem at hand.

ER70-Ti is a high strength gas shielded welding wire steel, which is suitable for ships, bridges and other structures, and can be used for thick plate welding with high current. In the welding wire industry, ER70-Ti is a high-tech deep-processing product with high added value. In this study, the thermal expansion experiment of ER70-Ti wire rod was carried out. The critical temperature of ER70-Ti phase transformation was measured and the continuous cooling transformation curve (CCT curve) of undercooled austenite was drawn. The microstructure and hardness of the samples under different cooling rates were observed. The results show that Ac1 temperature of ER70-Ti sample was 690 °C, Ac3 temperature was 877°C, and Bs temperature was 575°C. When the cooling rate was low (0.1°C/s~2.5°C/s), the phase transformation products of ER70-Ti were equiaxed polygonal ferrite and granular bainite. With the increase of cooling rate, the grain size of ER70-Ti sample was refined and the bainite content increased from 53% to 85%. When the cooling rate was higher than 5°C/s, all the phase transformation products were bainite. The Vickers microhardness also increased with the increase of cooling rate, from 185HV to 325HV.

Recent developments in gamma spectroscopy and data processing techniques opened up the possibility of providing high degrees of flexibility for different kinds of ambient, cosmic, and sample-related background suppression. The BALQARAD clover active shield is a newly acquired germanium detector that offers extraordinary and non-conventional time registers in the List File mode to optimize the setup in its different operation modes. The setup's geometry has been optimized for clover-active shield detector coincidences or anti-coincidences, depending on the details of the particular radioactive sources (22Na, 60Co, and 137Cs). The system consists of plastic scintillation plates that detect cosmic rays within coincidences with the clover. The time delay between the cosmic and clover detector was tested, and the time window of 640 ns was detected by addressing two desired prompt and delayed signals. The registered spectra were characterized by very prominent continua, obscuring low-intensity peaks of weak gamma-ray emissions. The peak-to-Compton ratio and peak-to-total ratio were greatly improved after using offline veto techniques, leading to much greater accuracy in determining the full-energy peak. The offline coincidence method's quick assessment points out the importance of reducing the Compton and background continua in detecting low activities and yields. This study will serve as a basis for more advanced national-level applications. It can benefit from advanced gamma detection systems with highly improved signal-to-background ratios associated with event selection techniques.

Background The present study aimed to propose a new foetal shielding device for pregnant cancer patients to reduce the foetal dose associated with treatment techniques using multiple gantry angles, such as intensity-modulated radiation therapy (IMRT) or volumetric modulated arc therapy (VMAT). Methods Three shielding structures were designed to minimise the scattered and leaked radiation from various gantry angles and radiation scattering within the patient. The base-plate part that can be placed on the treatment couch was designed to reduce the scattered and leaked radiation generated at gantry angles located near 180°. A body shielding part that can cover the lower chest and abdomen was designed, and a neck-shielding structure was added to reduce the internal and external radiation scattering from the treatment area. Evaluation plans were generated to assess the foetal dose reduction by the foetal shielding device in terms of the shielding material thickness, distance from the field edge, and shielding component using the flattened 6 MV photon beam (6MV) and flattening filter-free 6 MV photon beam (6MV-FFF). In addition, the effectiveness of the foetal shielding device was evaluated in a pregnant brain tumour patient. Results The shielding material consisting of three parts was placed on frames composed of four arch shapes with a vertical curved structure, connection bar at the top position, and base plate. Each shielding part resulted in reductions in the radiation dose according to the treatment technique, as the thickness of the shielding material increased and the foetal dose decreased. In addition, a foetal dose reduction of approximately 50% was confirmed at 50 cm from the field edge by using the designed shielding device in most delivery techniques. In patients, the newly designed shielding structures can effectively eliminate up to about 49% of the foetal dose generated from various gantry angles used in VMAT or IMRT. Conclusions We designed a foetal shielding device consisting of three parts to effectively reduce the dose delivered to the foetus, and evaluated the device with various treatment techniques for a pregnant patient with brain tumour. The foetal shielding device shielded the scattered/leaked radiation from the treatment machine, and also effectively reduced internal scattering from the treatment area in the patient.

Spread spectrum time domain reflectometry (SSTDR) is used to test dielectric aging of a cable type used in the nuclear power plant industry. A 16 AWG twisted pair shielded cable is thermally aged to the equivalence of 50 years in service, and SSTDR data are collected at 10-year intervals during the aging process. The SSTDR data shows that velocity of propagation and characteristic impedance decrease as the cable ages (increasing the electrical permittivity), making them suitable markers for monitoring aging and demonstrating the ability of SSTDR to determine this aging.

Existing practices for monitoring heart activity rely heavily on electrocardiography (ECG) approaches, which suffer from low accuracy (as electric fields get impacted by biological tissues); extensive diagnostic times; and lack of comfort (as electrodes are in direct contact with the human body). Though magnetocardiography (MCG) provides more accurate and localized signals while also being non-contact, state-of-the-art equipment for capturing such weak magnetic fields (i.e., SQUIDs) requires extensive shielding and is very expensive. MCG sensing devices that do not require shielding have been reported, but they are sbulky, heavy, and cumbersome to use. In this work, we take a major step forward and propose a novel, miniature, and low-cost MCG sensor for operation in non-shielded environments that breaks the state-of-the-art boundaries in terms of size and weight. Our sensor relies on novel coil design principles and Digital Signal Processing (DSP) algorithms to achieve: (a) 4.67 times smaller diameter, (b) 4.5 times smaller height, and (c) at least 216 times lighter weight than previous passive implementations. In vitro measurements demonstrate that a 4-coil sensor array with 15 minutes of recoding time is sufficient to capture human MCG signals. Discussions indicate that higher number of coils and longer recording times can be employed to improve the signal clarity and fit diverse clinical needs. The proposed coil sensor array provides a convenient method to diagnose several cardiac conditions, such as myocardial ischemia, arrhythmia, right atrial hypertrophy, right ventricular hypertrophy, and the Brugada syndrome.

A parameterized finite-element model of braided cable shields is developed to investigate the analytical model and study the influence of parameter and material dependencies of the transfer impedance of braided cable shields. The parameter influences and their interrelations are analyzed by the use of global sensitivity analysis. Measurements are only needed for the validation of the finite-element model but not for parameter variations. This reduces time and costs and eliminates measurement uncertainties occurring at different measurement procedures.

In this paper, the shielding enclosure of an electromagnetic interference (EMI-) filter for a spacecraft power bus was analysed for shielding effectiveness (SE). By using an electro- dynamic approach, the authors conducted simulation in the frequency domain taking into account losses in the shield. The investigation covered the performance of the shielding enclosure with and without the connected cables and the in uence of apertures formed between the enclosurebase and its cover. It was found that the smallest value of the SE of the enclosure is observed for the configuration with unshielded cables. However, whilst maintaining shielding integrity, attenuation of at least 88 dB in the frequency range from 0 to 20 GHz was achieved. In the study, the authors analysed the in uence of printed circuit boards of EMI-filter in the shielded volume on SE of the enclosure and found that they have a weak effect on the SE. In conclusion, there is some practical guidance on the design of similar EMI-protection devices.

The crystal structures of four pentakis-tert-butyl hexa-peri-hexabenzocoronenes (HBCs), each with an additional sixth substituent namely iodide, methoxy, formyl, and nitro, are presented. We show that the additional substituent has a significant impact on the packing in the solid state and the data obtained can be utilised for crystal engineering. By introducing an electron accepting substituent it was possible to achieve columnar arrangements that were previously unknown for such highly tert-butylated HBCs. In this way we provide insight into the aggregation behaviour of nanographenes with sterically highly shielded edges.

In recent years, electromagnetic compatibility (EMC) has become progressively important because of the rise in the number of electronic auxiliary devices in motor vehicles. This article presents an angle modulated switching strategy for fractional horsepower drives. It allows decreasing the size of the necessary EMC filter, for the example case drive used, down to less than 50%, from nine to four capacitors. Simultaneously, it reduces the radiated electromagnetic emissions over a wide frequency range by almost 10 $\,\text{dB}_{\mu \text{V/m}}$ . The EMC measurements performed in a shielded chamber are compared with the results for two conventional switching strategies. Subsequently, the influence of the presented switching strategy on the efficiency and on the emitted airborne and structure-borne noise is investigated.

Nickel alloying element has been known to play a role in controlling the formation of microstructures in the weld metal (WM). This experiment aims to study the relationship between nickel addition to the microstructure evolution and toughness of shielded metal arc welded SS400 low carbon steel plates. Three welded samples, Ni-01, Ni-03 and Ni-09 were fabricated using electrodes containing different nickel