Effect Of Metal Particles Research Articles

Effect of metal particles on the surface charge buildup of GIL insulators under electro-thermal coupling field

Effect of metal particles on the surface charge buildup of GIL insulators under electro-thermal coupling field

The effect of metal particles on surface flashover characteristics of alumina ceramic under pulse voltage in vacuum

The effect of metal particles on surface flashover characteristics of alumina ceramic under pulse voltage in vacuum

Effect of Metallic Particles on Breakdown Voltage of N2 Gas in Uniform Field

Effect of Metallic Particles on Breakdown Voltage of N2 Gas in Uniform Field

Lightning Impulse Breakdown Voltage RBDPO with the Presence of Metallic Particles Under a Uniform Electric Field

The performance of liquid insulation in power transformer is vulnerable to particles, especially the metallic particles. This paper presents the experimental study on the effect of metallic particles on the palm oil (PO) as dielectric insulating fluid under lightning impulse breakdown voltage. The type of PO used in this study is refined, bleached and deodorized Palm Oil (RBDPO) Olein. Two different types of metallic particles (copper and iron) with different concentrations (clean, low, medium, and high) were studied. The lightning impulse test has been carried out according to IEC 60897 standard and under the influence of a uniform electric field. For the comparative purpose, similar test has been carried out with mineral oil (MO). The presence of metallic particles reduces the average lightning impulse breakdown voltage of MO and PO but shows less significant effect to MO. This is because the streamers in the PO propagate faster and further than in the MO at the same voltage level. Hence, causing the breakdown voltage of PO lower than MO. Under negative lightning impulse, the breakdown voltage of MO is slightly higher than RBDPO. From the study, the increment of the number of particle level contamination will reduce the lightning impulse breakdown voltages of the PO.

Effect of metal powder Nickel, Iron and Aluminium on Mechanical and Electrical Properties of Epoxy Composites

Epoxy composite hold fabricated products used in different applications such as housing, electrical equipment, automobiles and insulators due to low thermal and electrical conductivity. The effect of metal particles (Al, Ni, Fe) content on physical and mechanical properties of such fabricated samples are investigated. Different weight fraction of metal particles (3, 6, 9, 12, and 15) wt. % with 10 wt. % SiC powder is blended by simple hand lay-up technique. According to the results of experiments, we discovered the increasing in the filler content leads to increase of the hardness and modulus elasticity are increasing too. At the same time, when filler in epoxy matrix increases, electric conductivity will increase and dielectric conductivity will decrease.

Ultrafine particle dispersion in the metropolitan area of Guadalajara, Mexico

Objectives: Dust, soil and leaf samples of Ficus benjamina were collected in the metropolitan area of Guadalajara (GMA) (Peña-García et al., 2017), allowing to identify the type of metallic particles, size, shape and spatial distribution. With the results obtained, the possible effects of metallic particles on human and plant health were discussed (Peña-García et al., 2019). Methodology: The sampling was in six municipalities of the GMA; Atomic absorption spectrophotometry analyses were carried out on leaves, which identified the presence of various elements that mostly exceeded the reference values. Through X-ray fluorescence, 23 elements were identified in soil, including Th and Ac in at least 14 sites. Using the scanning electron microscopy technique and elemental mapping analysis, coarse, fine and ultrafine metallic particles were identified in human bronchus and lung tissue, as well as fragments of cement, plastic, yeast and bacteria. The similarity between the metallic particles in the collected samples and those observed in lung tissue, warns of latent risks to the health of the GMA population. Contribution: The results obtained with the methodology used in this work allow us to glimpse the polluting potential in urban areas.

Effect of metal particles on promoting the nucleation of tetra-n-butylammonium semiclathrate hydrate

Abstract The formation of tetra-n-butylammonium bromide (TBAB) hydrate from a TBAB aqueous solution tends to show a supercooling phenomenon, which is non-ideal for the practical use of TBAB hydrate. However, as reported in the literature, the products obtained from the use of metal electrodes for the application of an electric field can accelerate the nucleation of the hydrate. Herein, we investigated the role of metal particles (Ag, AgBr, Zn, and ZnO) and their mixed forms (Ag–AgBr and Zn–ZnO) on promoting the nucleation of TBAB semiclathrate hydrate. The nucleation-promoting effect was most significant for the mixed metal particles when prepared by simultaneous grinding of the metal particle components. The changes in the physicochemical properties of the mixed metal particles as a result of grinding were believed to accelerate the nucleation of TBAB hydrate.

Neural cell responses to wear debris from metal-on-metal total disc replacements

PurposeTotal disc replacements, comprising all-metal articulations, are compromised by wear and particle production. Metallic wear debris and ions trigger a range of biological responses including inflammation, genotoxicity, cytotoxicity, hypersensitivity and pseudotumour formation, therefore we hypothesise that, due to proximity to the spinal cord, glial cells may be adversely affected.MethodsClinically relevant cobalt chrome (CoCr) and stainless steel (SS) wear particles were generated using a six-station pin-on-plate wear simulator. The effects of metallic particles (0.5–50 μm3 debris per cell) and metal ions on glial cell viability, cellular activity (glial fibrillary acidic protein (GFAP) expression) and DNA integrity were investigated in 2D and 3D culture using live/dead, immunocytochemistry and a comet assay, respectively.ResultsCoCr wear particles and ions caused significant reductions in glial cell viability in both 2D and 3D culture systems. Stainless steel particles did not affect glial cell viability or astrocyte activation. In contrast, ions released from SS caused significant reductions in glial cell viability, an effect that was especially noticeable when astrocytes were cultured in isolation without microglia. DNA damage was observed in both cell types and with both biomaterials tested. CoCr wear particles had a dose-dependent effect on astrocyte activation, measured through expression of GFAP.ConclusionsThe results from this study suggest that microglia influence the effects that metal particles have on astrocytes, that SS ions and particles play a role in the adverse effects observed and that SS is a less toxic biomaterial than CoCr alloy for use in spinal devices.Graphic abstractThese slides can be retrieved under Electronic Supplementary Material.

Local Biological Reactions and Pseudotumor-Like Tissue Formation in relation to Metal Wear in a Murine In Vivo Model.

Metal wear debris and released ions (CoCrMo), which are widely generated in metal-on-metal bearings of hip implants, are also found in patients with metal-on-polyethylene bearings due to the mechanically assisted crevice corrosion of modular taper junctions, including head-neck and neck-stem taper interfaces. The resulting adverse reactions to metal debris and metal ions frequently lead to early arthroplasty revision surgery. National guidelines have since been published where the blood metal ion concentration of patients must consistently be monitored after joint replacement to prevent serious complications from developing after surgery. However, to date, the effect of metal particles and metal ions on local biological reactions is complex and still not understood in detail; the present study sought to elucidate the complex mechanism of metal wear-associated inflammation reactions. The knee joints in 4 groups each consisting of 10 female BALB/c mice received injections with cobalt chrome ions, cobalt chrome particles, and ultra-high-molecular-weight polyethylene (UHMWPE) particles or PBS (control). Seven days after injection, the synovial microcirculation and knee joint diameter were assessed via intravital fluorescence microscopy followed by histological evaluation of the synovial layer. Enlarged knee diameter, enhanced leukocyte to endothelial cell interactions, and an increase in functional capillary density within cobalt chrome particle-treated animals were significantly greater than those in the other treatment groups. Subsequently, pseudotumor-like tissue formations were observed only in the synovial tissue layer of the cobalt chrome particle-treated animals. Therefore, these findings strongly suggest that the cobalt chrome particles and not metal ions are the cause for in vivo postsurgery implantation inflammation.

Impact of platinum group metals (Ru, Pd, Rh) on the dissolution of UO2

The effect of metallic particles containing Platinum Group Metal (PGM) elements on the dissolution of sintered UO2 samples was examined through the development of multiparametric dissolution tests on sintered UO2 and UO2 + 3 mol.% PGM samples. This effect was found to be more important for CHNO3 < 1 mol L−1 whereas it was lowered for higher nitric acid concentrations due to the preponderant oxidation of U(IV) by nitrate ions. Increase of the normalised dissolution rate of the ceramics was associated to the presence of PGM elements along with the decrease of the duration of the induction period (the stronger effect being observed for ruthenium). Simultaneously, the decrease of the apparent activation energy associated to the reaction of dissolution supported the existence of catalytic effect. This latter was connected to redox reaction between the metallic particles and nitrate ions either in solution or at the PGM/UO2/solution interface. The involved reactions induced the formation of nitrogen species close to the PGM bearing particles. Among them, nitrous acid played an important role due to its strong oxidative power regarding to U(IV). Additionally, no synergistic effect was evidenced when mixing the three PGM elements.

Effect of metal particles on the electrical properties of mineral and natural ester oils

Metal particles, such as copper and iron, not only reduce the breakdown voltage but also accelerate the oxidation of insulating oils. The effects of metal particles on the dielectric properties of mineral and natural ester insulating oils were investigated in this work. The experimental results indicate that the AC and impulse breakdown voltages of the insulating oil decrease with the increase of the size and the quantity of the metal particles. The positive breakdown voltages V b+ of insulating oils decrease moderately in the beginning, while the particles quantity increases to a certain extent, the V b+ decreases significantly. In comparison, the metal particles always reduce the negative impulse breakdown voltage V b− significantly. The effect of the copper particles on the insulating oils is slightly greater than that of the iron particles due to their higher conductivity. The permittivity of contaminated insulating oils increases quasi-linearly with the concentration of copper particles. Improved models considering the polarization of the surface oxidation layer of copper particles were proposed, and the calculated data were in good agreement with the measured permittivity of the contaminated insulating oil.

Development of Coatings for Radar Absorbing Materials at X-band

The present review gives a brief account on some of the technical features of radar absorbing materials (RAMs). The paper has been presented with a concentrated approach towards the material aspects for achieving enhanced radar absorption characteristics for its application as a promising candidate in stealth technology and electromagnetic interference (EMI) minimization problems. The effect of metal particles doping/dispersion in the ferrites and dielectrics has been discussed for obtaining tunable radar absorbing characteristics. A short theoretical overview on the development of absorber materials, implementation of genetic algorithm (GA) in multi-layering and frequency selective surfaces (FSSs) based multi-layer has also been presented for the development of radar absorbing coatings for achieving better absorption augmented with broadband features in order to counter the radar detection systems.

Effect of metal particles in cermets on spectral selectivity

Most cermet-based coatings achieve their solar selectivities by the tandem interference effect, which has been widely studied. This study focused on the spectral selectivity achieved by the scattering effect of metal particles in cermet-based coatings. Previous research proved that reasonable solar selectivities can be obtained for cermets in the regime of particles with a radius of the order of 100 nm, but their solar absorptance is low (&amp;lt;90%). In our research, the effect of metal particles on the spectral selectivity of cermets was studied by the Mie theory and Monte Carlo simulation for Cr, Ni, and W particles with radii of 10 nm, 50 nm, 100 nm, and 200 nm, which were embedded in Al2O3 and occupied 5% of the volume fraction. It was found that by arranging different particles in different layers, a very high solar absorptance (95.6%) could be achieved. Since their thermal emittance (∼25% at 600 °C) was higher than that of normal coatings, these coatings are recommended to be used in solar absorbers that have a high concentration factor. Finally, the dependent scattering effect was qualitatively considered by the coupled-dipole approach. With a metal volume fraction of 5%, it was found that the effect of dependent scattering was small and should not change the conclusions made based on independent scattering.

Effect of metal particles on the rate of Si etching with N-fluoropyridinium salts

The effect of Cr, Mn, Fe, Ni, Cu, Zn, Pd, Ag, Pt, or Au metal particles on the rate of Si etching using N-fluoropyridinium salts was examined. The average etching depth increased when N-fluoropyridinium salts were mixed with Cu particles. The activation energy determined from the temperature dependence of the average etching rate for the Cu particles is lower than that without a metal. The Cu particles greatly improve the etching of Si with the salts compared with the other metals. The magnitude of the effect of the Cu particles on the rate of Si etching with the salts is larger than that of the Mn, Fe, Ni, or Zn particles. This can be explained by the order of the relative stabilities of the complexes formed by bivalent ions of transition metals. The etching method involves the application of easy-to-handle salts containing Cu particles as etchants on the Si surface and has the potential to be a simple and less expensive form of Si etching.

Research Progress of the Metal-based Photonic Crystals

Metal-based photonic crystals (PCs), which provide a unique optic-electric properties based on its intrinsic char- acteristic, is of great significance for the applications in the field of new energy system, such as solar cells, water electrolysis, light emitting diode (LED), etc. This article reviews the research progress of the metal-based PC, including the fabrication method, property investigation and the relative applications. Metal-based PCs are generally fabricated from the building blocks of metal, metal oxide or their composites materials. The fabrication method refers to the bottom up and top down ap- proach. Bottom up approach covers the self-assembly of the metal nanoparticles directly or infiltrating the nanoparticles into the opal template and the subsequent removal of the template toward the metal-based inverse opals. Top down approach re- fers to the lithography and deposition. The lithography approach includes laser lithography, reaction ion etching, etc. And the deposition method covers physical vapor deposition, atomic layer deposition, pulsed laser deposition, etc. Furthermore, the metal-based PCs demonstrate many excellent properties based on the combination of the light manipulation property of PCs and the intrinsic property of the metal materials. For example, the materials showed surface-enhanced Raman effect, which can provide special optic signal and demonstrate the application in high-sensitive detecting of organic molecules. The com- bination of Plasmon effect of metal particles and photonic stopband of the PCs can improve the emission intensity, which is significant for the application in high efficient detecting of special material. Otherwise, the stopband of metal-based PCs is beneficial for the improvement of the optic adsorbent property and photoluminescence property. Furthermore, the combina- tion of metal materials and its suitable stopband can amplify its optic-electronic property, sensing property and the op- tic-catalytic behavior. Finally, the potential applications of metal-based PCs on the new energy system is put forward. Typi- cally, it was used as optic-electric materials in solar cell, water electrolysis, and high efficient LED. This review will provide an important insight for the new energy development and potential utilization.

Effect of Metallic Particles on E-field Enhancement in Extra High Voltage Gas-insulated Transmission Lines

Gas-insulated transmission lines (GITL) are valued as technological solutions in hydropower stations due to their enormous power handling capabilities. The performance of GITL is a function of the size of metallic particles inside the gas-insulated chamber. Electrostatic field (E-field) enhancement is a common phenomenon in gas-insulated lines due to these metallic particles. In this study, the E-field enhancement factor is calculated by considering metallic particles at various locations in the gas-insulated line/bus section, such as high-tension (HT) conductor, high-voltage shields, support insulator, and inner surface of grounded enclosure. For this purpose, a two-dimensional model based on finite element (FE) method is developed. The length of the metallic particle is in the range of 1 to 10 ㎜ while the diameter is between 1 to 3 ㎜. E-field enhancement is also computed for various particle configurations of the gas-insulated system, with focus on dielectric coating made of epoxy on HT conductor and inner surface of grounded enclosure.

Effect of Metal Particles on Spreading Properties of Sn0.7Cu Based Composite Solder

The particle-reinforced composite solder is prepared by adding 1 μm Ag, 1 μm Ni and 8 μm Cu into Sn0.7Cu eutectic solder which serve as the base material in current research. The formation of a thin layer of intermetallics around the particle-reinforced will promote the closer integration between base-solder and particle-reinforced, and thus form the particle-reinforced composite solder. The appropriate reinforcement particles were selected and the effects of reinforcement particles on physical properties, mechanical properties and solderability of the composite solder were studied. The spreading property of Ni (3 vol %) particle-reinforced Sn0.7Cu based composite solder was the worst among Sn0.7Cu based composite solders. The spreading property of the Cu particle-reinforced Sn0.7Cu based composite solder was worse than those of Ag particle-reinforced Sn0.7Cu based composite solders. So the conclusion is drawn that Ag particles are considered as the most appropriate reinforced particles for Sn0.7Cu based composite solders.

Fluorescence lifetime correlation spectroscopic study of fluorophore-labeled silver nanoparticles.

In this paper, we introduce the use of fluorescence lifetime correlation spectroscopy to study the metal-fluorophore interactions in solution at the single-fluorophore level. A single-stranded oligonucleotide was chemically bound to a 50-nm-diameter single silver particle, and a Cy5-labeled complementary single-stranded oligonucleotide was hybridized with the silver particle-bound oligonucleotide. The distance between the fluorophore and silver particle was maintained by a rigid hybridized DNA duplex of 8 nm in length. The single Cy5-DNA-Ag particles showed more than 10-fold increase in fluorescence intensity and a 5-fold decrease in emission lifetimes as compared with Cy5-DNA free molecules in the absence of metal. The decrease of lifetime for the Cy5-DNA-Ag particle allowed us to resolve the correlation functions of the two species based on the intensity decays. The increased brightness of the Cy5-DNA-Ag particle as compared to free Cy5-DNA resulted in an increased contribution of Cy5-DNA-Ag to the correlation function of the mixture. These results show that the effects of metal particles on fluorophores can be used to detect the small fractional populations of the metal-bound species in the presence of a larger number of less bright species. Our results also suggest that these bright fluorophores conjugated to silver particles could be used as the fluorescent probes for clinical detection in the biological samples with the high background.

Microstructural characterisation of a plasma carburised low carbon Co–Cr alloy

One of the major concerns over long term metal on metal articulations is the carcinogenic effect of metal particles. How to improve the surface hardness and wear resistance of Co–Cr–Mo alloys and thus extend the life span of the metal on metal joint prostheses is a timely task from both a scientific and clinical viewpoint. The present investigation indicated that plasma carburising a Co–Cr alloy between 400 and 600°C can produce a hardened layer on the surface which can significantly improve its wear resistance. Detailed structural, composition and microstructural characterisation have advanced the scientific understanding of the hardening effect. This is the first report that S phase can be formed in Co–Cr alloys during low temperature plasma carburising.

EFFECT OF METAL PARTICLES (Mo) INCLUSION INTO INSULATING MATRIX (Al2O3)

The effect of metal particles ( Mo ) inclusion in an insulating matrix ( Al 2 O 3) has been investigated. The conducting phase ( Mo ) is dispersed in alumina in different amounts (00%, 5%, 10%, 20%, 25% in volume). Two types of Mo particles have been used: the first with an average particle size ≅0.56 μm, the other with an average particle size ≅10.0 μm. All specimens were fabricated by hot pressing. The bulk conductivities have been measured over temperatures ranging from 500°C to 900°C using two-probe impedance spectroscopy within the available frequency range (5 Hz–13 MHz). From the interpretation of the impedance spectra, it has been observed that the bulk conductivity for fine particles of Mo inclusion in alumina is higher than that for large particles of Mo inclusion in alumina. A microstructural study revealed that below 15 vol% of Mo inclusion in Al 2 O 3 samples had no-contact random patterns. Samples with metal contents higher than 20 vol% of Mo consistently showed metallic conductivity due to percolation effect.