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In the present work, the nano-Al2O3 powder was produced by the wire explosion technique. The shape and size of the particles were measured using Transmission Electron Microscope (TEM) studies. The Scanning Electron Microscope (SEM) studies were carried out to confirm that the particles are of sub-micron size. The compositions of the material were characterized through the Energy Dispersive Angle X-ray Analysis (EDAX) results. The Wide Angle X-ray Diffraction (WAXD) and the Fourier Transform Infra-Red (FTIR) results confirmed the nanosize powder formed by the process as crystalline γ-Al2O3 powder. It is identified that the local temperature of the medium at the time of formation of nanopowder decides the phase characteristics of the powder material. The mechanism of formation of nanopowder by wire explosion technique was explained in detail. [Copyright &y& Elsevier]

• Variety of fluorescent fibers with different absorption/emission characteristics were used for identification of corona and surface discharges, and we find that a particular type of fluorescent fiber is more sensitive to identify discharges in liquid nitrogen insulation than UHF technique. The characteristic spectral content of the fluorescent signal due to corona and surface discharge activity formed in liquid nitrogen is observed up to 3 MHz. • Enhancement in the magnitude of fluorescent signal/UHF signal is observed for increase in applied voltage beyond the corona inception voltage (CIV). Also, it is observed that while reducing the applied voltage, the corona activity quenches at much lower voltage than the inception voltage. • It is observed that 3 wt% of nano mgo added GFRP epoxy nanocomposite sample exhibits enhanced surface discharge inception voltage (SDIV) compared to samples with other concentrations of mgo and that the SDIV is lower for AC voltage when compared with the DC voltage conditions. • A phase-resolved partial discharge (PRPD) analysis was also carried out to identify corona and surface discharge activity using fluorescent fiber sensor and with UHF sensor. From the PRPD studies, it is observed that the corona discharge occurs near the peak magnitude whereas surface discharge is observed at the rising part of AC voltage. Identification of incipient discharges is a major challenge in liquid nitrogenbased super-conducting power apparatus. In the present study, a variety of fluorescent fibers with different absorption/emission characteristics were used for the identification of corona and surface discharges, and we find that a particular type of fluorescent fiber is more sensitive to identify discharges in liquid nitrogen insulation than the UHF technique. Enhancement in the magnitude of fluorescent signal/UHF signal is observed for an increase in applied voltage beyond the corona inception voltage (CIV). Also, it is observed that while reducing the applied voltage, the corona activity quenches at a much lower voltage than the inception voltage. No characteristic variation in rise time or the fall time of the fluorescent signal is observed on corona inception and due to discharges at higher voltages. The corona inception voltage is least for AC voltage conditions, and slightly higher inception voltage is observed for positive DC and negative DC voltage conditions. Different weight percentages of MgO doping in GFRP nanocomposites are prepared and used in the surface discharge studies. It is observed that the 3 wt% sample exhibits enhanced surface discharge inception voltage (SDIV) compared to samples with other doping concentrations and that the inception voltage is lower for AC voltage when compared with the DC voltage conditions. The characteristic spectral content of the fluorescent signal due to corona and surface discharge activity is observed up to 3 MHz. A phase-resolved partial discharge (PRPD) analysis was also carried out to identify corona and surface discharge activity using fluorescent fiber sensor and with a UHF sensor. From the PRPD studies, it is observed that the corona discharge occurs near the peak magnitude whereas surface discharge is observed at the rising part of AC voltage. [ABSTRACT FROM AUTHOR]

This article reports an experimental investigation of the impact of magnetic field on corona discharge activity in mineral oil, using both ultrahigh-frequency (UHF) and fluorescence techniques under ac voltage. The results show that corona inception voltage (CIV) increased under ac voltage with varying harmonic frequencies without considering any phase shift and reduced marginally under magnetic field. In addition, the impact of the magnetic field shifted the dominating frequency of the UHF signal (0.9 GHz) obtained under ac voltage toward lower frequencies (0.3 and 0.6 GHz). Under high magnetic fields, the parameters such as rise time, fall time, and pulsewidth of the fluorescence signal increased in its magnitude compared to its effect without a magnetic field. Also, using both the UHF sensor and the fluorescence sensor, there was no clear difference in the phase-resolved partial discharge (PRPD) pattern caused by corona discharge (with and without magnetic field). Furthermore, the number of discharges is observed to be high under the impact of harmonic ac voltages with third- and seventh-order containing total harmonic distortions (THDs) of 4% and 40%. [ABSTRACT FROM AUTHOR]

Present study deals with the acquisition and analysis of different types of incipient discharges in transformer by adopting Ultra-High Frequency (UHF) technique. The Nyquist rate sampling method generates a large number of samples, making it inefficient for developing an online monitoring system. To reduce this, compressive sensing techniques are employed for signal compression and reconstruction. Various compressive sensing methods, including Convex, Non-Convex, Greedy, and Iterative Thresholding, were compared. Orthogonal Matching Pursuit (OMP) was found to be the optimal algorithm, achieving optimal reconstruction time and error at a compression ratio of 45%. The reconstructed signals were compared with the originals using Fast Fourier Transform (FFT), revealing similarities in dominant frequencies. A Long Short-Term Memory (LSTM) machine learning model was used for signal classification, consistently outperforming other algorithms. This study enhances understanding of incipient/partial discharge detection and classification, highlighting the effectiveness of innovative signal processing and machine learning approaches in power system engineering. [ABSTRACT FROM AUTHOR]

The micro-aluminium trihydrate (ATH) and nano-alumina fillers in the silicone rubber (SR) significantly improve the electrical, thermal and mechanical properties. ATH fillers improved the resistance to the corona ageing and water droplet-initiated erosion. Scanning electron microscopy (SEM) analysis was carried out to understand degradation condition caused due to corona ageing and damage caused due to water droplet-initiated discharges. The inclusion of these fillers significantly altered the surface and bulk charge distribution characteristics of the polymer. A right shift is observed in the trap distribution characteristics. The reduced electric field threshold limit for space charge formation is observed with composites, due to increment in impurities/agglomerations with respect to increment in filler concentration. Performance of composites subjected to polarity reversal is improved on inclusion of nano-filler in addition to micro-filler. The inclusion of fillers enhanced the thermal conductivity and improved significantly thermal stability of the SR composite. [ABSTRACT FROM AUTHOR]

Life expectancy of a thermally aged oil impregnated pressboard (OIP) in the presence of corrosive dibenzyl disulphide (DBDS) is studied in this work using a fast estimation method based on level of diffusion of Cu contaminant. Data from laser induced breakdown spectroscopy (LIBS) is used as the degradation parameter. Thermogravimetric analysis (TGA) is used for rapid evaluation of life expectancy at various temperatures. Aged OIP material is tested for its surface flashover breakdown strength and its thermal stability is studied by TGA and differential scanning calorimetry. Thermal activation energy is estimated using Flynn-Wall-Ozawa method and is agreement with isothermally calculated values. Aging law is derived and found to be nearly first order based on which temperature dependent life expectancy law is formulated. LIBS data of OIP collected from a failed transformer is considered to be end-of-life condition. Estimated life expectancy values using proposed fast method are compared with traditional long-aging evaluation and are in good agreement. Increase in corrosive DBDS concentration and change in aging medium using proposed method and are found to have a significant impact on life expectancy of the OIP insulation. [ABSTRACT FROM AUTHOR]

• In the present study, corona inception voltage in liquid nitrogen under standard lightning impulse voltage (SLIV) and oscillatory impulse voltages were studied using fluorescent fiber sensor. • Under unidirectional oscillatory impulse voltage (UOIV) and sinusoidal bidirectional oscillatory impulse voltage (SBOIV) conditions, Corona discharge occurs around the peak of the first cycle. When the applied voltage is increased, the discharges occur in the subsequent cycles. • Under switching impulse voltage (SIV), corona discharge is noticed at the rising edge in positive polarity, whereas in negative polarity, it is observed at the falling edge. The corona discharge inception voltage (CDIV) is determined to be highest under Unidirectional Oscillating Lightning Impulse (UOLI) and lowest under SI. The negative polarity exhibits more temporal spread than the positive polarity under oscillating impulse voltages. In the present study, corona inception voltage in liquid nitrogen under standard lightning impulse voltage (SLIV) and oscillatory impulse voltages were studied using fluorescent fiber sensor. A single discharge signal is observed near the peak of the applied SLIV. The amplitude of the fluorescent signal is high with positive polarity than under negative polarity. At higher voltages, the magnitude of the fluorescence signal increases and it shifts towards the rising edge of the applied voltage. Under unidirectional oscillatory impulse voltage (UOIV) and sinusoidal bidirectional oscillatory impulse voltage (SBOIV) conditions, Corona discharge occurs around the peak of the first cycle. When the applied voltage is increased, the discharges occur in the subsequent cycles. Under switching impulse voltage (SIV), corona discharge is noticed at the rising edge in positive polarity, whereas in negative polarity, it is observed at the falling edge. The corona discharge inception voltage (CDIV) is determined to be highest under Unidirectional Oscillating Lightning Impulse (UOLI) and lowest under SI. The negative polarity exhibits more temporal spread than the positive polarity under oscillating impulse voltages. [ABSTRACT FROM AUTHOR]

The primary concerns in the adhesive bonding of metal substrate surfaces include inadequate wettability, compatibility, and insufficient mechanical interaction at the bonding interface. These factors are significant barriers to developing and manufacturing high-strength bonded materials. This study utilized three different anodising techniques, such as H 3 PO 4 , H 2 SO 4 , and NaOH, to produce micro-rough surfaces that improve the adhesive bond between aluminium alloy and mild steel. A novel and a simple method known as resin pre-coating (RPC) were used to increase the wetting and effectively seal the micro-cavities of mild steel and aluminium surfaces. RPC solution comprises 10 wt% resin (Absence of hardener) and 90 wt% acetone, which facilitated the penetration of resin into the microcavities surface, thereby increasing the bonding surfaces. Subsequently, the normal adhesive mixed with hardener is placed onto the metal surfaces. The adhesive bonding strength was evaluated by conducting the single lap shear test under various surface conditions. The surface topography of anodised samples were examined by X-ray Photoelectron Spectroscopy (XPS), Atomic Force Microscopy (AFM), Field Emission Scanning Electron Microscopy (FESEM), and Contact Angle Goniometer. Experimental results of a lap shear test revealed that the adhesive bond strength of H 3 PO 4 anodised samples is greater than those of H 2 SO 4 and NaOH anodised samples. Furthermore, the RPC treatment increased the bond strength of all H 3 PO 4 anodised samples by 46.91–47.26 %, for H 2 SO 4 samples by 39.71–42.22 %, and NaOH samples by 37.89–48.51 %, compared to the readings obtained without RPC treatment. The combined use of H 3 PO 4 and RPC treatment results in the greatest bonding strength of 16.765 MPa, which is 9.17 % and 20.10 % greater than the bonding strength of H 2 SO 4 and NaOH anodised samples. Thus, the H 3 PO 4 anodised method improved the wetting ability of the metal surface and maximized the use of contact area on the rough substrate surfaces. The anodising treatment details in this study are inexpensive and simple for creating strong adhesive joints in aviation, automobile, and aerospace applications. [Display omitted] [ABSTRACT FROM AUTHOR]

Radionuclides are monitored in the atmosphere for the signatures of nuclear explosions, as part of the verification of the Comprehensive Nuclear-Test-Ban Treaty (CTBT). Civil nuclear facilities, such as Nuclear Power Plants (NPPs) and Isotope Production Facilities (IPFs) are sources of anthropogenic radionuclides in the atmosphere and these signatures are sometimes indistinguishable to those of a nuclear explosion. In order to improve the understanding of civil radionuclide-emitting facilities and their impact on the International Monitoring System (IMS) of the CTBT, a group of scientists from the UK, US and Sweden are collaborating with EDF Energy UK to measure radionuclide emissions from an Advanced Gas-cooled Reactor (AGR) nuclear power station. Emissions are being measured at the source, via a stack monitor and high-resolution gamma spectrometry measurements of filters and also at tens of kilometres away via three sensitive radioxenon atmospheric samplers. The timing, isotopic composition, activity magnitudes and other release parameters of interest are investigated, to improve the discrimination between a civil radionuclide release and an explosive nuclear test. This paper outlines the work of the Xenon and Environmental Nuclide Analysis at Hartlepool (XENAH) collaboration, describes the equipment fielded and provides initial results from each measurement campaign. [ABSTRACT FROM AUTHOR]

In this work, two different surface treatments, such as grinding and acid-pickling, were applied to both mild steel and aluminum alloy substrates for performance comparison. A novel method known as resin precoating (RPC) has been used effectively to seal the micro-cavities surface and enhance substrate wetting. The RPC solution consists of 10 % resin, and 90 % acetone (without hardener) is applied onto the grinding and acid-pickling metal substrate. The acetone solution facilitates resin penetration into the micro-cavities formed through grinding and acid pickling. It enables effective coating and wetting of micro-debris, ultimately eliminating micro-voids or gaps between the metal substrate and the adhesive joint. Then, the standard K-300 adhesive (with hardener) is applied to the metal substrate surface. The adhesive bonding strength was determined using a single-lap shear test on varied surface conditions. The topography of surface-treated samples was analyzed using X-ray Photoelectron Spectroscopy (XPS), Atomic Force Microscopy (AFM), Scanning Electron Microscopy (SEM), and Contact Angle Goniometer. The grinding and acid-picking surface treatment increased the surface roughness of the substrate, which reduced the contact angle and improved the mechanical interlocking effect. The single lap shear test results show that the bonding strength of the grinded samples was superior to that of the acid-pickled samples. The RPC treatment further enhanced the bonding strength of all the grinded samples by 16.83–19.77 % and for acid-pickled samples by 20.79–44.97 %, which is higher than the values observed without RPC treatment. The combination of grinding and RPC surface-treated samples exhibited a superior bonding strength of 14.05 MPa. This value was 12.38 % greater than the bond strengths of acid-pickled samples, and the failure mode shifted from adhesive to cohesive failure mode. Thus, RPC treatment enhanced the wettability of metal substrates and maximized the utilization of contact areas on roughened substrate surfaces, consequently improving adhesive bond strength. These grinding and acid-pickling surface treatments are effective and well-suited for aerospace, automobile, and aviation applications. [Display omitted] [ABSTRACT FROM AUTHOR]

Titanium carbide (TiC) nanoparticles have been synthesized by exploding titanium wire in methane as well as diluted acetylene atmosphere at different gas pressures. The synthesized samples have been annealed to enhance the level of carburization and to reduce the amount of excess amorphous carbon present on the surface of the as-synthesized nanoparticles. The crystallinity, surface morphology and surface area of the produced nanocarbide samples have been probed by various characterization techniques. The size of the carbide nanoparticles was measured using lognormal distribution derived from transmission electron microscopy analysis. An increase in the applied energy shows a significant reduction in particle size irrespective of the operating pressure. Further, TiC nanoparticles have been utilized to study the CO 2 adsorption properties at different temperatures and in low pressure (≤1 bar). The synthesized nanoparticles may not show very high adsorption capacities, but significant enhancement in adsorption has been observed when compared to bulk TiC. The isosteric heat of adsorption was determined from the variation of pressure with temperature at a constant excess gas uptake. The standard enthalpy change (Δ H) observed during adsorption manifests that the adsorption process in TiC is exothermic and within the range of physisorption such that the gas can be regenerated easily from the material utilizing minimum energy. • TiC nanoparticles were synthesized using single step wire explosion technique. • The samples were synthesized in CH 4 and Ar/C 2 H 2 atmospheres. • An increase in the applied energy showed a significant reduction in particle size. • The size of the nanoparticles was measured using lognormal distribution. • The synthesized nanoparticles were utilized to study low pressure CO 2 adsorption. [ABSTRACT FROM AUTHOR]

Zinc Oxide (ZnO) nanoparticles were synthesized by wire explosion process through deposition of different levels of energy to the exploding conductor in oxygen ambience at different pressures. The produced nanoparticles were analyzed by transmission electron microscopy (TEM), X-ray diffraction (XRD), energy dispersive analysis of X-rays (EDAX) and by Brunauer-Emmett-Teller (BET) studies. Energy dependent formation reaction mechanisms were formulated based on Born-Haber cycle. The size dependent gas phase reaction energetics was analyzed by using Hess's diagram. Butler's multicomponent molten oxide model was adopted to predict the surface tension of ZnO. Thermodynamic modelling studies revealed that the amount of energy deposited has an impact on saturation ratio, activation free energy, and nucleation rate of nanoparticles. It is observed based on experimental and modelling studies that the amount of energy deposited to the current carrying conductor, ambient pressure of oxygen and the saturation ratio influence the size of nanoparticle formed. [ABSTRACT FROM AUTHOR]

[Display omitted] • We demonstrate the formation of homogeneous Ni 80 Cr 20 alloy nanoparticles (NPs) by novel wire explosion process (WEP). • Chemical/physical synthesis techniques do not yield desired composition due to incompatible standard reduction potential. • The superparamagnetic behavior is identified in 34 nm diameter particles and attributed to uncompensated surface spins. • From present study we conclude that WEP is a potential synthesis method to produce alloy NPs with homogeneous composition. We report a detailed study of the structural and magnetic properties of Ni 80 Cr 20 fine particles prepared by physical methods, such as mechanical alloying, wire explosion process (WEP), and chemical methods like sodium borohydride reduction, polyol method. From the analysis of structural and microstructural data, phase formation with the desired composition is confirmed in the particles prepared by the WEP. A comparative study of magnetization data of bulk and nanoparticles of Ni 80 Cr 20 suggests that a weak magnetic moment develops in nanoparticles due to finite-size effects. Analysis of magnetization data suggests a superparamagnetic (SPM) behavior in the smallest sized (34 nm) particles prepared by WEP, while nanoparticles prepared by other methods show ferromagnetic ground state. Further, it is shown that the origin of weak magnetic moment and development of SPM state in the nanoparticles is due to uncompensated surface spins with a negligible interaction effect. [ABSTRACT FROM AUTHOR]

In the present study, Al–Mg binary eutectic alloy nanoparticles were synthesized through the electrical wire explosion technique (EWET) in an inert ambience. High-speed imaging was carried out to visualize sublimation process of alloy wire and subsequent formation of nanoparticle through the condensation process. The fundamental gas-phase kinetics is investigated by the embedded atom method (EAM) and reactive hard-sphere model to elucidate the mechanisms governing the formation of finer particles of eutectic Al-Mg alloy. The condensed phase transformations are analysed through size-dependent thermodynamics and growth kinetics modelling, which has shown that the adsorption controlled growth is responsible for the generation of polydispersed particles. The formation of Al 20 Mg 23 nanoparticles and its morphological features were characterised through XRD and SEM/EDS analysis. High-resolution transmission electron microscopy (HRTEM) along with the selected area electron diffraction (SAED) confirmed the spherical morphology, crystallinity, lognormal particle size distribution and the multiphase microstructure of the eutectic AlMg nanoparticles. The formation of multiphase alloy nanoparticles is attributed to the insignificant difference in melting temperatures of Al and Mg and phase boundary modifications due to size-effect. Scanning transmission electron microscopy (STEM) revealed the spatial distribution of Al and Mg within the alloy nanoparticle. Differential scanning calorimetry (DSC) confirmed the reduction in melting temperature and fusion enthalpy of eutectic Al–Mg alloy nanoparticles. It is proposed as a potential substitute for Al nanoparticles to reduce the ignition temperature, agglomeration and two-phase flow losses for realising improved combustion performance in solid rocket propellants. Image 1 • Size-effect and eutectic effect are combined to yield low-melting alloy nanoparticles to reduce the ignition temperature. • Low-melting multiphase eutectic Al-Mg alloy nanoparticles were synthesized by wire explosion technique and characterized. • The gas-phase kinetics is investigated by the EAM and reactive hard-sphere model to elucidate their formation mechanisms. • A new Al 30 Mg 23 phase is formed upon explosion due to non-equilibrium quenching processes. • Al-Mg eutectic nanoparticles are proposed as viable additives for solid rocket propellants and high energy applications. [ABSTRACT FROM AUTHOR]

The purpose of the Comprehensive Nuclear-Test-Ban Treaty (CTBT) is to establish a legally binding ban on nuclear weapon test explosions or any other nuclear explosions. The Preparatory Commission for the CTBT Organization (CTBTO PrepCom) is developing the International Monitoring System (IMS) that includes a global network of 80 stations to monitor for airborne radionuclides upon entry into force of the CTBT. All 80 radionuclide stations will monitor for particulate radionuclides and at least half of the stations will monitor for radioxenon. The airborne radionuclide monitoring is an important verification technology both for the detection of a radionuclide release and in the determination of whether the release event originates from a nuclear explosion as opposed to an industrial use of nuclear materials. Nuclear power plants and many medical isotope production facilities release radioxenon into the atmosphere. Low levels of a few particulate isotopes, such as iodine, may also be released. Detections of multiple isotopes are useful for screening the radionuclide samples for relevance to the Treaty. This paper examines the anticipated joint detections in the IMS of noble gas and particulate isotopes from underground nuclear explosions where breaches in the underground containment vents from low levels to up to 1% of the radionuclide inventory of the resulting fission products to the atmosphere. Detection probabilities are based on 844 simulated release events spaced out at 17 release locations and one year in time. Six different release (venting) scenarios, including two fractionated scenarios, were analyzed. When ranked by detection probability, 11 particulate isotopes and one noble gas isotope ( 133 Xe) appear in the top 20 isotopes for all six release scenarios. Using the 11 particulate isotopes and the one noble gas isotope, the IMS has nearly the same detection probability as when 45 particulate and 4 noble gas isotopes are used. Thus, a limited list of relevant radionuclides may be sufficient for treaty verification purposes. The probability that at least one particulate and at least one radioxenon isotope would be detected in the IMS from the release events ranged from 0.15 to 0.86 depending on the release scenario., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Battelle Memorial Institute, The Author(s). Published by Elsevier Ltd.. All rights reserved.)

Background: Electro-permeablization using a pulse generator is a novel non-invasive approach for cancer therapy. It serves as a cell permeability enhancing agent for cancer treatment., Objective: In this article in vitro investigation of the effect of 1.0 kV/cm, 1.5 kV/cm and 2.0 kV/cm, 50 µs duration pulsed electric field on MCF-7 cell line has been done. Furthermore, combinational therapy of curcumin and electrical pulses has been also investigated., Material and Method: A variable voltage (100 V-1200 V, 100 V step) and 50 µs duration pulse generator has been designed, which is further used for the investigation of electroporation and destructive electrical field intensity. Investigation of the effect of electrical pulses on cancer cells has been performed using Trypan Blue Exclusion Test, MTT Assay and Clonogenic Assay., Results: It has been observed that electrical field intensity of 2 kV/cm, 50 µsec duration, 10 pulses at repetition rate of 1 pulse per second corresponding to total energy of 4 J is more than enough for causing necrotic cell death due to permanent damage of cell membrane of the cancer cell. Also, it has been observed that electrical pulse application enhances curcumin uptake by cells., Conclusion: Electrical pulses can effectively inhibit the cancer cell growth and proliferation. Furthermore, observation shows that electroporation enhances the curcumin uptake, therefore, it can be used for therapeutic purposes., (Copyright © 2022 Copyright: © 2022 Journal of Cancer Research and Therapeutics.)

The objective of the present study is to develop eco-friendly purifying agents from natural materials, Strychnos potatorum (SP) - a coagulant. The seeds of SP were used for wastewater treatment (washing machine effluent). Physico-chemical parameters like turbidity, total dissolved solids (TDS), electrical conductivity (EC), pH, calcium (Ca 2+ ), magnesium (Mg 2+ ) and phosphate (PO 4 3- ) were tested and the data obtained were compared with BIS standards. In the current work, physical and chemical parameters have been examined to determine the quality of water for washing machine discharge, before and after treatment (coagulation) using SP seeds. The testing procedure was carried out using a Jar test of coagulant mass 1000 mg/L with rapid mixing at 150 rpm for 5 min, slow mixing at 30 rpm for 25 min and a settling period of 1 h. Coagulation results were reported for the use of SP seeds, where the effectiveness of removing turbidity and PO 4 3- was determined to be 81.54 and 41.45%. The presence of various functional groups in SP seed was assessed by fourier transform infrared (FT-IR) spectroscopy. Qualitative identification of phytochemical constituents of seed extract for this species was also carried out. The experimental findings strongly highlighted the ability of SP seeds to remove turbidity and PO 4 3- from wastewater., Competing Interests: The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (© 2023 The Authors.)

Three unusual radioactive isotopes of xenon- 125 Xe, 127 Xe, and 129m Xe-have been observed during testing of a new generation radioxenon measurement system at the manufacturing facility in Knoxville, Tennessee. These are possibly the first detections of these isotopes in environmental samples collected by automated radioxenon systems. Unfortunately, the new isotopes detected by the Xenon International sampler can interfere with quantification of the radioactive xenon isotopes used to monitor for nuclear explosions. Xenon International sampling data collected during February through September 2020 were combined with an atmospheric transport model to identify the possible release location. A source-location analyses using sample counts dominated by 125 Xe strongly supports the conclusion that the release point is near (within 20 km) the sampler location. Wind patterns are not consistent with releases coming from more distant nuclear power plants. The High Flux Isotope Reactor (HFIR) and the Spallation Neutron Source (SNS) at Oak Ridge National Laboratory are located in the region of most likely source locations. The source-location analysis cannot rule out either facility as a release location, and some of the samples may contain a combination of releases from both facilities. The source-location results using 125 Xe are not unexpected because Klingberg et al. (2013) previously published the production rate of radioactive xenon isotopes from neutron activation of stable xenon in the air at the HFIR. Up to 10 12 Bq of 125 Xe could be produced per operational day and other xenon isotopes would be produced in lesser quantities., (Copyright © 2022 Elsevier Ltd. All rights reserved.)

Hydrothermal and chemical aging tests on a 230 kV cross-linked polyethylene (XLPE) insulation cable were carried out in the present study to evaluate the degradation and aging levels qualitatively. The samples were subjected to water aging at a temperature of 80 °C, and in an aqueous ionic solution of CuSO 4 at room temperature. The diffusion coefficient results indicated that the ion migration was not at the same rate in the aging conditions. The diffusion coefficient-D-of the sample immersed in an aqueous CuSO 4 solution was lower than the hydrothermally aged specimens. The hydrophobicity of aged specimens decreased considerably compared to unaged samples. The distribution of trapped charges was quantitatively characterized. The presence of shallow trap energy states were observed in unaged XLPE, whereas the deep trap sites were noticed in aged specimens. In addition, the charge trap characteristics were different for positive and negative charge deposition. Various material characterization techniques, viz. dynamic mechanical analysis (DMA), tensile, contact angle, and LIBS, were further employed on the aged and virgin specimens. The tensile behavior of the hydrothermally aged specimen was degraded due to the oxidised regions, which had formed a weak spot against the mechanical stress. Reduced glass transition temperature and increased loss tangent measurements were noticed for aged specimens over their unaged counterparts. Machine learning techniques, such as the principal component analysis (PCA) and the artificial neural network (ANN) analysis, were performed on LIBS spectral data of the samples to classify the aging mechanisms qualitatively.

Epoxy micro-nano composites are well-known to exhibit enhanced electrical, mechanical as well as thermal properties compared to base epoxy resin. Yet, a clear understanding need to be achieved on the long-term aging performance of the epoxy micro-nano composites. The present review article is a comprehensive study on the impact of gamma irradiation and water aging on the space charge characteristics of epoxy micro-nano composites that are applicable as insulant in high-voltage power apparatus. Ion-trapping nanoparticles, which possess good oxidation resistance and high ion trapping ability, are being chosen as nanofillers along with silica micro fillers in epoxy micro-nano composite material for improving the reliability of electrical insulation structures. The epoxy micro-nano composite specimens were subjected to gamma irradiation (4 kGy and 8 kGy) and water aging (under room temperature and at 90 °C), to analyze the effect of aging on space charge accumulation and charge decay characteristics. The mean magnitude of accumulated space charge density of epoxy micro-nano composites tends to increase with an increase in gamma irradiation dose as well as an increment in water diffusion coefficient. The mean lifetime of the space charge decay during depoling has significantly reduced after gamma irradiation and is converse with water aged specimen. Voltage polarity reversal studies have indicated that a part of homo-charge injected from electrodes remained as hetero-charge just after polarity reversal and could result in the distortion of electric field thereby increasing the electric field enhancement factor.

In this particular work, a simple, cost-effective and single step process to synthesize magnesium oxide modified nitrogen doped porous carbon (MgO/NMC) by thermal decomposition technique has been elaborated and its high-pressure performance as CO 2 and CH 4 gas adsorbent is demonstrated. The uniformly distributed porous network in the samples was identified from the morphological studies by FESEM and TEM. Elemental analysis and XPS studies were carried out to understand the Mg and N contents. It has been observed that MgO/NMC shows appreciably high CO 2 (30 mmol g -1 at 20 bar and 25 °C) as well as CH 4 (12 mmol g -1 at 30 bar and 25 °C) adsorption capacity. The surface modification of the samples (caused by the presence of MgO nanoparticles) along with high surface area and good porosity containing interconnected macro-/ meso-/ micropores synergistically improves the adsorption capacity. In addition, high nitrogen content in the nanocomposite enhances the number of basic adsorption sites thereby increasing the gas adsorption capacity. The effect of concentration of MgO on gas adsorption capacities has also been investigated from the adsorption isotherms. The moderate heat of adsorption, as well as good recyclability and selectivity at high pressure, shows that MgO modified nitrogen doped porous carbon composite can be a promising candidate for both CO 2 capture and CH 4 storage., (Copyright © 2018 Elsevier Inc. All rights reserved.)

A wire explosion process (WEP) has been used to produce nano aluminium powder in nitrogen, argon and helium atmospheres. The impact of energy deposited into the exploding conductor on the size and shape of the particles was analysed using TEM analysis, which forms the first part of the study. It is observed that the higher the energy deposited, the smaller the particles formed. In the second part, modelling studies were carried out by solving the general dynamic equation through the nodal approach, and the particle size distributions were predicted. It is realized that, at the point of high saturation ratio and nucleation rate, the size of the critical nucleus formed is low. The particle size distribution predicted by the model correlates well with the experimental results. Time-series analysis of particle formation indicates that particles of lower dimensions form and, in the process of coagulation, larger particles are formed. It is realized that the plasma formed during the explosion plays a major role in the particle formation, and the modelling studies confirm that particle formation is not an instantaneous process but requires a certain time period to form stable sizes and shapes.