Electric Probe Research Articles

Non-contact measurement method of busbar voltage phase of substation arrester

• The non-contact measurement method of busbar voltage phase for substation arresters is studied. • The principles of phase measurement are derived by formulas. • Three typical spatial models of arresters are established. • The optimal locations of double detection points are recommended under different conditions. The resistive current of metal oxide arrester (MOA) is an important parameter for evaluating the aging condition of arrester. To extract the resistive component from the full current, the phase angle between the full current and the busbar voltage must be known. In conventional measurement, the voltage signal needs to be acquired from the secondary side of the capacitor voltage transformer (CVT), so there is a risk of short circuit to trigger equipment damage. To solve the above problems, a non-contact measurement method for the busbar voltage phase of substation arrester is proposed. By placing suitable electric field probe under the arrester, the busbar voltage phase is derived from the electric field information. Moreover, models of ultra-high voltage (UHV) substation arresters based on actual operation are constructed to verify this method, and the optimal placement of probes is given. The results show that the error is relatively minimum when the electric field probe is placed between the arrester and the CVT and is 1.3 m – 2 m away from the arrester. In addition, the arrangement of double detection points proposed can not only obtain the phase sequence of the three-phase voltage of the power grid, but also average the measurement errors.

Design and Experimental Evaluation of a Printed Monopole Antenna for GPR Applications

In this paper, a printed monopole antenna is designed and experimentally evaluated for Ground Penetrating Radar (GPR) applications. The antenna resonates at two narrow frequency bands centered at 0.5 GHz and 2 GHz. Four stages are used to achieve the final model, which is based on a rectangular patch, a simple microstrip feed line, and a reduced ground plane. The proposed antenna consists of a simple patch with notches and a quarter-wavelength feed line. The introduced notches help to reduce the conductor losses and decrease the weight of the design. The antenna prototype is fabricated on a low-cost FR-4 epoxy substrate with dimensions of 17.55 cm3, using the LPKF S103 laser printer, and then measured with the R&S®ZNB Vector Network Analyzer. The experimental results demonstrate that the operating bands range between 0.48–0.52 GHz (8%) and 1.94–2.04 GHz (5.02%). The antenna exhibits good radiation patterns with a reasonable gain of 1.5/2.6 dBi and a high radiation efficiency of 97/78% at the two resonating frequencies 0.5/2 GHz, respectively. To validate the usefulness of the designed antenna for GPR applications, a penetrability test is conducted through a concrete separator wall. The electric field probe HZ551 is used to receive the electromagnetic waves behind the obstacle, and the power received by the probe is measured with the GSP-730 spectrum analyzer. The obtained results confirm that the proposed model performs well in the UHF band at 0.5 GHz and 2 GHz, with a high level of penetrability.

Review on Subsea Pipeline Integrity Management: An Operator’s Perspective

For operators of oil and gas to save the cost of unforeseen events and risks, and to avoid unnecessary shutdowns, there is a need to have an effective subsea pipeline integrity management system. Currently a large number of subsea pipelines around the globe have already exceeded their design lives; nevertheless, they are still being operated safely, effectively and with diligent consideration towards Environmental, Health and Safety regulations, as well as international standards and best practices. In addition, many older flowlines have no permanent pigging facilities due to various design and operational limitations. For the unpiggable pipeline, the vast majority of the oil and gas operators use different inspection and monitoring techniques to provide essential integrity management data such as product chemistry, cathodic protection, electrical resistance probes and coupons, etc. However, translating such essential integrity management data into meaningful information to make crucial integrity-based decisions can be challenging. This paper presents a holistic approach that implements the required pipeline integrity management tools to facilitate the safe operation and maintenance of pipeline systems going forward. This paper also provides a review of the integrity of the ageing pipelines and underlines the practical pipeline integrity management steps and systems that maintain the condition of the subsea assets going forward.

3D Nanoprinting of All-Metal Nanoprobes for Electric AFM Modes.

3D nanoprinting via focused electron beam induced deposition (FEBID) is applied for fabrication of all-metal nanoprobes for atomic force microscopy (AFM)-based electrical operation modes. The 3D tip concept is based on a hollow-cone (HC) design, with all-metal material properties and apex radii in the sub-10 nm regime to allow for high-resolution imaging during morphological imaging, conductive AFM (CAFM) and electrostatic force microscopy (EFM). The study starts with design aspects to motivate the proposed HC architecture, followed by detailed fabrication characterization to identify and optimize FEBID process parameters. To arrive at desired material properties, e-beam assisted purification in low-pressure water atmospheres was applied at room temperature, which enabled the removal of carbon impurities from as-deposited structures. The microstructure of final HCs was analyzed via scanning transmission electron microscopy-high-angle annular dark field (STEM-HAADF), whereas electrical and mechanical properties were investigated in situ using micromanipulators. Finally, AFM/EFM/CAFM measurements were performed in comparison to non-functional, high-resolution tips and commercially available electric probes. In essence, we demonstrate that the proposed all-metal HCs provide the resolution capabilities of the former, with the electric conductivity of the latter onboard, combining both assets in one design.

Study of the Effect of External Magnetic Fields on the Parameters of the Electrical Communications Probing System for a Microtunneling Shield

The issues were reviewed in assessing external electromagnetic fields’ effect on the parameters of an electrical power line probing system based on three-component ferroprobes for detecting active underground power cable lines during microtunnel construction using the thrust boring method (by tunneling shield) in densely populated urban areas. A study was conducted on the change in the topology of the energized cable magnetic field located in the external magnetic field area created by operating electrical equipment under the influence of an external electromagnetic field and a tunneling shield with installed magneto-sensitive detectors. Experimental studies of the probing system were made. Options have been proposed for compensating the inductance component of the external magnetic field during tunnel driving in urban development and industrial area conditions.

EXPERIMENTAL STUDY OF CURRENT-SHEET-LIKE STRUCTURE IN PINCHING PLASMA FLOW WITH ELECTRIC AND MAGNETIC PROBES

The formation of the current-sheet-like structure under the influence of the external magnetic field in pinching plasma flows generated by the magnetoplasma compressor has been studied. A set of magnetic and electric probes were used to measure the self-generated magnetic field, electron temperature, and electric field locally with sufficiently high temporal and spatial resolution. The data obtained from the probe measurements were used to plot the spatial distributions of electric current and drift velocity in the plasma stream to identify the patterns of plasma flow. In the presence of external magnetic field, the current density, electron temperature, and the ion saturation current reach a peak in close proximity to the sheet. Measurements indicate the outflow of two electron jets of different temperatures from the layer.

INFLUENCE OF THE MAGNETIC FIELD OF THE CURRENT PASSING THROUGH THE ANODE ON A GLOW DISCHARGE IN A COAXIAL SYSTEM

To study the influence of the magnetic field on the normal low-pressure glow discharge, an electrode coaxial system with a meshy tubular cathode and an internal anode was used. A current was passed through the anode to obtain the azimuthal magnetic field crossed with electric field. Oscillography of the signals from the electric probe and photodiode, together with video recording, made it possible to establish the movement of the discharge luminous region along the electrodes. When AC current with a frequency of 50 Hz was passed through the anode, the discharge movement was oscillatory – from one end of the system to another.

Experimental study of submerged liquid metal jet in a rectangular duct in a transverse magnetic field

A liquid metal flow in the form of a submerged round jet entering a square duct in the presence of a transverse magnetic field is studied experimentally. A range of high Reynolds and Hartmann numbers is considered. Flow velocity is measured using electric potential difference probes. A detailed study of the flow in the duct's cross-section about seven jet's diameters downstream of the inlet reveals the dynamics, which is unsteady and dominated by high-amplitude fluctuations resulting from the instability of the jet. The flow structure and fluctuation properties are largely determined by the value of the Stuart number ${{N}}$ . At moderate ${{N}}$ , the mean velocity profile retains a central jet with three-dimensional perturbations increasingly suppressed by the magnetic field as ${{N}}$ grows. At higher values of ${{N}}$ , the flow becomes quasi-two-dimensional and acquires the form of an asymmetric macrovortex, with high-amplitude velocity fluctuations reemerging.

Investigation of charged particles dynamics along with self-generated electric and magnetic fields in axially resolved laser-induced magnesium plasma

Laser ablated Mg plasma was generated by employing Nd-YAG laser (532 nm, 10 ns). Faraday cups with Electric and Magnetic probes have been employedto evaluate axial plasma parameters and Self-Generated Electric and Magnetic Fields (SGEMFs) at various axial distances from target (1 cm to 4 cm) and at various laser irradiances 1.8 GW/cm2 to 4.5 GW/cm2. The evaluated number densities of ions vary from 1.4 × 1013 cm−3 to 6.91 × 1013 cm−3 and electron number densities variation is from 2.38 × 1013 cm−3 to 5.15 × 1013 cm−3. The electron temperature varies from 1.3 eV to 125 eV, whereas, ion kinetic energies vary from 114 eV to 385 eV. Moreover, self-generated electric field variation is from 0.28 V/cm to 20 V/cm and magnetic field is from 978 Gauss to 2628 Gauss. Furthermore, the maxima of ion signal amplitude have been observed at 3 cm distance from target, whereas, electron signals amplitude decreases as Faraday cup to target distance increases. Both evaluated SGEMFs show decreasing trends with increasing target to probe distances and increase with increasing laser irradiance. It is observed that the shape of SGEMFs signals have been significantly affected by increasing laser irradiances and transform from unipolar to dipolar. The charge separation of plasma species, two-electron temperature distribution and bipolar signals of SGEMFs confirm the quadruple distribution of charges in plasma. It uncovers the importance of ion and electron number density gradients in plasma.

High-Voltage Biomolecular Sensing Using a Bacteriophage Portal Protein Covalently Immobilized within a Solid-State Nanopore.

The application of nanopores as label-free, single-molecule biosensors for electrical or optical probing of structural features in biomolecules has been widely explored. While biological nanopores (membrane proteins and bacteriophage portal proteins) and solid-state nanopores (thin films and two-dimensional materials) have been extensively employed, the third class of nanopores known as hybrid nanopores, where an artificial membrane substitutes the organic support membrane of proteins, has been only sparsely studied due to challenges in implementation. G20c portal protein contains a natural DNA pore that is used by viruses for filling their capsid with viral genomic DNA. We have previously developed a lipid-free hybrid nanopore by "corking" the G20c portal protein into a SiNx nanopore. Herein, we demonstrate that through chemical functionalization of the synthetic nanopore, covalent linkage between the solid-state pore and the G20c portal protein considerably improves the hybrid pore stability, lifetime, and voltage resilience. Moreover, we demonstrate electric-field-driven and motor protein-mediated transport of DNA molecules through this hybrid nanopore. Our integrated protein/solid-state device can serve as a robust and durable framework for sensing and sequencing at high voltages, potentially providing higher resolution, higher signal-to-noise ratio, and higher throughput compared to the more conventional membrane-embedded protein platforms.

INTRAOPERATIVE NON-INVASIVE LEFT VENTRICULAR MYOCARDIAL WORK INDICES IN PATIENTS UNDERGOING ON-PUMP CORONARY ARTERY BYPASS SURGERY

<h3>Objective</h3> Non-invasive echocardiographic analysis of left ventricular (LV) myocardial work (MW) enables insights into cardiac mechanics, contractility, and efficacy beyond ejection fraction and global longitudinal strain. MW incorporates myocardial deformation and loading conditions into its analysis and correlates well with invasively measured myocardial work outside the operative setting. However, there are no reports on the use of this method by transesophageal echocardiography (TEE) in patients undergoing coronary artery bypass graft (CABG) surgery. Therefore, we aim to describe the intraoperative course of this novel assessment tool of ventricular function in these patients and compare it to conventional two- and three-dimensional echocardiographic parameters and strain analysis. <h3>Design and Method</h3> Twenty-five patients scheduled for isolated on-pump CABG surgery with preoperative preserved left and right ventricular function and a complication-free intraoperative course, were included into this prospective observational trial. TEE was performed intraoperatively after induction of anesthesia (T1), after termination of cardiopulmonary bypass (T2), and after sternal closure (T3) using General Electric Vivid E95 echocardiography machines and 6VT-D TEE probes. All measurements were performed under stable hemodynamic conditions, in sinus rhythm or atrial pacing and vasopressor support with Norepinephrine ≤ 0.1 µg/kg/min. EchoPAC v204 software (GE Vingmed Ultrasound AS, Norway) was used for analysis of 2D- and 3D LV ejection fraction (EF), LV global longitudinal strain (GLS), LV global work index (GWI), LV global constructive work (GCW), LV global wasted work (GWW) and LV global work efficiency (GWE). <h3>Results</h3> Myocardial work analysis was feasible in all patients. Although there was no significant difference in the values of 2D- and 3D-EF during the intraoperative interval, GLS deteriorated significantly after CABG compared to assessment after induction of anesthesia (T1 v T2, -13.3±3.0% v -11.6±3.1%; p=0.012). GWI declined significantly after surgery (T1 v T2, 1224±312mmHg% v 940±267mmHg%; p<0.001) as well as GCW (T1 v T2, 1460±312mmHg% v 1244±336 mmHg%; p=0.005). GWW increased after CABG (T1 v T2, 143mmHg% (IQR 99-183) v 251mmHg% (IQR 179-361); p<0.001) and GWE decreased (T1 v T2, 89% (IQR 85-92) v 80% (IQR 75-87); p<0.001). There was no significant change in the values of 2D- and 3D-EF, GLS, GWI, GCW, GWW and GWE before and after sternal closure (T2 v T3). <h3>Conclusions</h3> Intraoperative non-invasive echocardiographic assessed left ventricular myocardial work analysis appears feasible in this study. In our small sample with 25 CABG patients, strain and myocardial work analysis showed a deterioration of left ventricular function. In the short-term period after uncomplicated on-pump CABG, global and constructive myocardial work was decreased, while wasted work was increased, resulting in a less efficient left ventricle. None of these aspects was detected by two- and three-dimensional ejection fraction. Therefore, myocardial work analysis might be a more sensitive parameter in detecting myocardial dysfunction by TEE in the perioperative setting.

Efficient Use of a Hybrid Chamber for Radiated Susceptibility Tests

This letter describes the design and operation of a novel type of hybrid chamber used for radiated susceptibility tests. This is a semi-anechoic chamber with the possibility to install a vibrating intrinsic reverberation chamber inside. This testing environment can be used for the execution of the radiated susceptibility tests using both the deterministic and stochastic methodologies but without changing the test location, nor moving the device under test with its auxiliary equipment. This allows test engineers to combine the advantages of both reverberation and semi-anechoic chambers with a minimum effort, making it a very practical, cost- and time-efficient solution. The electric field into the reverberation chamber is monitored by eight electric field probes, permitting the closed-loop control of the electric field strength level and an efficient real-time analysis of the performance indicators discussed in this letter.

Skate, overtravel, and contact force of tilted triangular cantilevers for microcantilever-based MEMS probe technologies

Microfabricated chip-edge microcantilevers are commonly used as surface probes, e.g. in near-field microscopy. Such probes normally function in the low-deflection regime, where their behaviour is very well understood and documented. In contrast, when microcantilevers are used for applications such as electrical testing probes, their deflection can be somewhat higher, taking them into the less well understood high-deflection regime of microelectromechanical systems (MEMS). Here, a scalable model for the relationship between the skate, overtravel, and resulting tip contact force in tilted triangular cantilevers—which are bending with high deflection and in contact with a flat surface—is presented. The model is tested experimentally using macroscopic triangular cantilevers—the experimental results agree well with the proposed model. The findings enable a practical solution for zero-skate in tapered MEMS probes to be suggested. It is hoped that the findings may be of use for probe engineers involved with on-wafer testing and designers of emerging MEMS micro cantilever-based probes.

The multipole resonance probe: simultaneous determination of electron density and electron temperature using spectral kinetic simulation

The multipole resonance probe (MRP) is an innovative sensor suitable for monitoring and control of industrial plasma processes. It is a realization of ‘active plasma resonance spectroscopy’, a class of electromagnetic diagnostic methods which employ the ability of plasmas to resonate on or near the plasma frequency. A signal in the GHz range is fed to the plasma via an electrical probe; the spectral response S(ω) is recorded, and then evaluated with a mathematical model to obtain information on the internal plasma parameters. In this study, a spectral kinetic model of the MRP is discussed. It is superior to previous analyses based on the Drude model, as it allows to determine not only the electron density n e but also the electron temperature T e from S(ω). Good agreement with independent measurements shows the suitability of the model.

Observation of non-thermal electrons outside the SOL in the Wendelstein 7-X stellarator

• Non-thermal electrons can be observed far outside the main plasma in W7-X. • Occurrence is limited to electron-cyclotron resonance heated plasmas at low density. • Electrons cause hot spots on plasma-facing components with considerable heat fluxes. Hot spots and bright patterns on plasma-facing components (PFC) in visible light are observed in electron cyclotron resonance heated (ECRH) plasmas at low densities in the stellarator Wendelstein 7-X. The events are often located far outside of any convective plasma loads and led in some cases to damages of diagnostic components, where the interaction zones qualitatively agree with fast particle loss simulations. Reciprocating electric probes indicate that this phenomenon is related to a non-thermal electron population that can have a beam like character, being directed in one parallel direction. Further, the electrons can be trapped on rational flux surfaces and be used to map magnetic islands.

Intrinsically Conductive Liquid Metal‐Elastomer Composites for Stretchable and Flexible Electronics

AbstractLiquid metal‐embedded elastomers (LMEEs) are a class of deformable composites made of particles of liquid metal dispersed in an elastomeric matrix. Although these composites possess high thermal conductivity, they are not intrinsically electrically conductive unless a stimulus is applied to join the liquid metal inclusions into a conductive pathway. LMEEs with intrinsic conductivity, especially with a conductive surface, have great potential uses in flexible and stretchable electronics as soft, nondamaging contacts for device characterization, stretchable interconnects for deformable circuits, and as a “soft solder” to electrically connect devices to flexible and stretchable substrates. Here, a simple process is introduced to fabricate intrinsically conductive LMEEs (iLMEEs) with conductive surfaces through the sedimentation of microparticles of eutectic gallium‐indium alloy (EGaIn) in the elastomer poly(dimethylsiloxane). During this sedimentation process, an EGaIn‐rich 3D percolation network forms at the bottom surface. The resulting iLMEE possesses a conductive surface comprising a mosaic of EGaIn particles embedded in PDMS, with a low sheet resistance of 0.63 ± 0.04 Ω sq–1. iLMEE is soft, stretchable, and exhibits stable conductivity to 100% strain. We demonstrate the use of iLMEE as nondamaging, reusable soft electrical contact probes and as mechanically robust electrical connections between light‐emitting devices and flexible plastic substrates.

Exploiting elastic buckling of high-strength gold nanowire toward stable electrical probing

SummaryBuckling is a loss of structural stability. It occurs in long slender structures or thin plate structures which is subjected to compressive forces. For the structural materials, such a sudden change in shape has been considered to be avoided. In this study, we utilize the Au nanowire’s buckling instability for the electrical measurement. We confirmed that the high-strength single crystalline Au nanowire with an aspect ratio of 150 and 230-nm-diameter shows classical Euler buckling under constant compressive force without failure. The buckling instability enables stable contact between the Au nanowire and the substrate without any damage. Clearly, the in situ electrical measurement shows a transition of the contact resistance between the nanowire and the substrate from the Sharvin (ballistic limit) mode to the Holm (Ohmic) mode during deformation, enabling reliable electrical measurements. This study suggests Au nanowire probes exhibiting structural instability to ensure stable and precise electrical measurements at the nanoscale.

The Effect of Dental Flourosis on the Electric Pulp Tester Response and Probe Placement Site.

Introduction: The probe placement site for an electric pulp tester. (EPT) will have a significant outcome for the threshold readings. These relationships in previous studies have been documented. As dental flourosis is an endemic in regions of Pakistan the aim of this study was to compare and determine the appropriate EPT probe placement sites on fluorotic and non flourotic teeth.&#x0D; Methodology: In this cross-sectional clinical study equal number of flourotic and non flourotic maxillary central incisors(40 volunteers) were selected from a known region of Pakistan for endemic of flourosis to measure threshold levels on EPT on four different parts of each tooth. (Incisal edge, incisal third, middle third and cervical third). Before the readings were taken flourotic teeth were also categorized on the bases of severity (Deans Index).The purpose was to assess if severity of dental flourosis had an impact on the EPT readings. Once the mean values were taken the Dunn–Bonferroni post hoc tests was used to assess the statistical significance (p&lt;0.05) between the four site in both groups.&#x0D; Results: Mean values from the EPT presented that the threshold values increased from incisal to cervical in gender and both age groups i.e. 20-29 and 30-40. It was also found that the threshold values increased from incisal edge to the cervical third in flourotic and non flourotic teeth. Statical significance was found between the reading of flourotic and non flourotic groups across the four probe site readings taken (p value= 0.00). Like previous literature the insical edge was considered the most ideal site for EPT assessment on anterior incisors. As this is where the lowest threshold response was recorded in our study .Dental flourosis does have a significant effect on the EPT threshold values. This is most likely due to structural changes because of dental flourosis.&#x0D; Recommendations: From the study conducted it can be recommended that clinicians need to be aware of the fact that fluorotic teeth response will vary from natural teeth on the EPT. Also further research needs to be done to assess if other vitality test methods will also alter in their response due to dental defects like flourosis.

Assessment of human exposure to EMF generated by 5G mobile phone base stations

The paper presents a preliminary survey over human exposure to radiofrequency (RF) electromagnetic field (EMFs) levels generated in the vicinity of the new 5G mobile phone base stations recently installed in different major cities in Romania in comparison with other different frequency bands already used for mobile phone base stations. Measurement of electromagnetic field levels has been performed in Iasi, one of the major cities of Romania. Measurements have been performed in different urban locations with a high density of mobile phone base stations (from national operators). The EMF exposure levels for different mobile communications technologies have been measured with a calibrated up to date NARDA SRM 3006 field strength analyser system connected to an isotropic electric field probe. The methodology described by ECC RECOMMENDATION (02)04 has been rigorously respected.

Investigation of number density, temperature, and kinetic energy of nanosecond laser-induced Zr plasma species for self-generated electric and magnetic fields in axial expansion of plume

The number density, temperature, and kinetic energy of laser-induced Zr plasma species have been evaluated experimentally under ultra-high vacuum conditions as a function of 1 to 4 cm axial distances of the plume at laser irradiances ranging from 4.5 to 11.7 G W c m − 2 . Zr plasma parameters have been evaluated using time-of-flight (ToF) measurements by using a Faraday cup (FC) as a diagnostic technique. The amplitudes of the signals as well as the number density and temperature are strongly dependent upon laser irradiance and axial distances. With increasing laser irradiance the laser-induced plasma (LIP) parameters show an increasing trend. The increasing trend of the plasma parameters along with increasing laser irradiance is attributed to an enhanced energy deposition per atom, which is responsible for an enhanced ablation rate, surface temperature, and ablation/shock pressures. However, a decreasing trend is obtained with increasing axial distances, which is explainable based on adiabatic expansion, cooling, and recombination losses. The LIP electron and ion number densities vary from 3.13 × 1 0 13 to 6.81 × 1 0 13 c m − 3 and 1.84 × 1 0 13 to 4.41 × 1 0 13 c m − 3 , respectively. The electron temperature varies from 1.54 to 125 eV, whereas the kinetic energy of the ions varies from 1.2 to 34 keV. The maxima of Zr plasma parameters are achieved away from the target surface. In order to correlate the charge particle distribution and their energies with self-generated electric and magnetic fields (SGEMFs), the measurements have been performed by employing electric and magnetic probes, respectively. The signal profiles of the SGEMFs reveal the quadrupolar distribution, which is attributed to two oppositely generated dipoles whose contribution is strongly dependent upon axial distances and laser irradiances. The strength of both SGEMFs shows an increasing trend with increasing laser irradiance, and a decreasing trend is obtained with increasing probe-target distance. For overall plume axial expansion, the LIP electric and magnetic fields vary from 30 to 3140 V/m and 0.2 to 0.4 T, respectively. Similar trends of the SGEMFs and the axial gradients of the electron-ion number density confirm the quadrupolar structure of plasma, which corresponds to the electron-ion charge separation. This charge separation is due to the spatially evolved number density and temperature gradients in the plasma. Their correlation and optimization will be helpful for using LIP as a powerful source of electric and magnetic fields in ion acceleration and inertial confinement fusion.