Accelerated aging investigation of high voltage EPDM/silica composite insulators

2016 ◽  
Vol 36 (2) ◽  
pp. 199-209 ◽  
Author(s):  
Abraiz Khattak ◽  
Muhammad Amin
Keyword(s):  
Electron Microscopy ◽  
Hybrid Composite ◽  
Visual Inspection ◽  
Accelerated Aging ◽  
Polymeric Materials ◽  
Ethylene Propylene Diene Monomer ◽  
Radiation Heat ◽  
Insulating Materials ◽  
Salt Fog ◽  
Scanning Electron

Abstract Ethylene-propylene-diene-monomer (EPDM) is one of the most frequently used outdoor insulating materials. Like other polymeric materials, EPDM and its composites also degrade in outdoor applications. For evaluation of aging of insulating materials, accelerated multistress aging/weathering is an efficient method. In the current paper, comparative multistress aging performance investigation of neat EPDM (NE), EPDM with 20% microsilica (microcomposite, EMC), EPDM with 5% nanosilica (nanocomposite, ENC) and EPDM 20% microsilica 5% nanosilica (hybrid composite, EHC) is presented. Materials prepared according to ASTM D3182-07 were subjected to uniform ultraviolet (UV) radiation, heat, humidity, salt fog and acid rain at 2.5 kV voltage for 5000 h in a specially fabricated weathering chamber. For timely analysis of the aged materials, Fourier transform infrared (FTIR) spectroscopy, Swedish Transmission Research Institute (STRI) hydrophobicity classification and scanning electron microscopy (SEM) were used along with the critical visual inspection. Increasing discoloration was found in all materials which was proportional to% wt of the filler in composites. Improved hydrophobicity and better surface smoothness was recorded in composites as compared to NE, which was higher in the case of the microcomposite and hybrid composite. FTIR results showed least reduction in hydrocarbon bonds and lowest variation in chalking index in the case of the microcomposite.

Evaluation of Three Different Cleaners Recommended for Ultrafiltration Systems by Direct Observations of Commercial-Scale Spiral-Wound Ultrafiltration Membranes1

1988 ◽  
Vol 51 (2) ◽  
pp. 89-104 ◽  
Author(s):  
K. E. SMITH ◽  
R. L. BRADLEY
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Visual Inspection ◽  
Membrane Materials ◽  
Direct Observations ◽  
Commercial Scale ◽  
Sweet Whey ◽  
Scanning Electron ◽  
Polysulfone Membranes ◽  
Spiral Wound

Efficacy of cleaners designed for use with ultrafiltration systems was determined by microbiological evaluation and through visual inspection using scanning electron microscopy. The ultrafiltration system containing two commercial-scale, polysulfone membranes was soiled with sweet whey (40°C) then rinsed with water and membranes were removed. One half of each membrane was soaked for 2 h at 38°C in one of the following solutions: control (no soaking), acid cleaner (pH 2.5), enzyme-based cleaner (pH 11.5) and chlorinated alkaline cleaner (pH 11.5). The membranes were repositioned in the ultrafiltration unit, rinsed with water, then removed and unwound for analysis. Sections of membrane, retentate spacer and permeate mesh were aseptically removed for enumeration of microorganisms remaining and for examination by scanning electron microscopy. Membranes cleaned with chlorinated alkaline cleaner averaged 2 × 103 CFU/50 cm2, enzyme-based cleaner 6 × 106/CFU, acid anionic cleaner 1 × 107 CFU and the control 5 × 107CFU. Scanning electron microscopy found soil and microorganisms present on all membrane materials exposed to all three cleaners.

Pre-Meeting Topical Conference

2002 ◽  
Vol 8 (I1) ◽  
pp. 20-20
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Low Voltage ◽  
Ion Beam ◽  
Analytical Electron Microscopy ◽  
Polymeric Materials ◽  
Specimen Preparation ◽  
Microbeam Analysis ◽  
Scanning Electron

Topic: Characterization of Non-Conductive or Charging Materials by Microbeam AnalysisThe goal of this topical conference is to present the state of the art for materials characterization of non-conductive or charging materials using microbeam analysis. Examples of charging materials include polymeric materials, ceramic materials, and photoresist materials in the microelectronic industry. Also, the characterization of biological specimens will be covered because they are prone to problems related to charging. These materials are of great technological importance and their characterization is still a great challenge because they charge when analyzed with an electron beam. The techniques of microbeam analysis that will be considered are: X-ray Microanalysis in the Electron Microprobe, Low Voltage Scanning Electron Microscopy, Environmental Scanning Electron Microscopy, Analytical Electron Microscopy with Field Emission Transmission Electron Microscopy, and Focused Ion Beam Milling for specimen preparation. World experts will present papers on these topics. Papers from this topical conference will be published in a special issue of Microscopy & Microanalysis.

Mechanical Properties of Hot Extruded Al (Mg)-MnO2 Composites

2015 ◽  
Vol 813-814 ◽  
pp. 84-89 ◽  
Author(s):  
S. Ghanaraja ◽  
D.J. Dileep Kumar ◽  
K.S. Ravikumar ◽  
B.M. Madhusudan
Keyword(s):  
Electron Microscopy ◽  
Metal Matrix ◽  
Base Alloy ◽  
Polymeric Materials ◽  
Hot Extrusion ◽  
Metal Alloys ◽  
Transportation Applications ◽  
Microstructural Studies ◽  
Modern Technologies ◽  
Scanning Electron

Many of our modern technologies require materials with unusual combinations of properties that cannot be met by the conventional metal alloys, ceramics and polymeric materials. This is especially true for materials that are needed for aerospace, underwater and transportation applications. An economical way of producing metal matrix composite (MMC) is the incorporation of the particles into the liquid metal and casting. The objective of this work is to reinforce Al 1100-Mg alloy with different wt% of MnO2 (0, 3, 6, 9 and 12) was added by melt stirring method and Hot Extrusion is carried out. Microstructural Studies using Scanning Electron Microscopy (SEM) and Mechanical property like hardness and tensile properties have been investigated for extruded base alloy and composites.

scholarly journals Pilot investigation into osteotome hard surface coating and cutting-edge degradation

2020 ◽  
Author(s):  
David White ◽  
Jim Bartley ◽  
Christopher Whittington ◽  
Lorenzo M. G. Garcia ◽  
Kaushik Chand ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Titanium Nitride ◽  
Visual Inspection ◽  
Visual Analysis ◽  
Electroless Nickel ◽  
Cutting Edge ◽  
Edge Sharpness ◽  
Blade Edge ◽  
Scanning Electron

Abstract BackgroundOsteotomes are bone cutting tools commonly reused in orthopedic surgical procedures. Despite undergoing rigorous cleaning, visual inspection and sterilization procedures between every use, the condition of the cutting blade edge is commonly not qualitatively assessed. Subjective feedback from surgeons suggests a large variation in osteotome cutting edge sharpness is found during use. This study seeks to investigate the retention of osteotome cutting-edge sharpness by comparing the wear resistance of as-supplied, electroless nickel, and titanium nitride coated osteotomes following a series of bone cutting tests.MethodsChanges in edge sharpness were assessed using visual inspection, depth penetration testing that quantified change in the blade sharpness index and scanning electron microscopy visual analysis. Visual inspection of each osteotome blade edge was then compared to qualitative blade sharpness index measurement.ResultsAfter use, no cutting-edge damage or change in blade sharpness was detected by visual examination of all three osteotomes however the as-supplied osteotome demonstrated 50% loss of blade sharpness index compared to 30% and 15% reduction for the electroless nickel and titanium nitride coated osteotomes respectively. This finding was supported by scanning electron microscopy evaluation that found greater mechanical damage had occurred along the cutting-edge of the as-supplied osteotome compared to the two coated with wear resistant materials.ConclusionsThe rapid loss of blade sharpness found in the as-supplied osteotome supports the degradation in cutting performance frequently reported by surgeons. The findings from this study demonstrates blade sharpness index better detects cutting edge wear compared to visual inspection. Results from this pilot study also suggest the coating of osteotomes in hard-wearing biocompatible materials assists in retaining cutting edge sharpness over multiple uses. Further study using a larger sample size is required to validate these findings.

scholarly journals Effect of Kevlar Fiber and Nano Sio2 on Mechanical Andthermal Properties of Hybrid Composites

2021 ◽  
Vol 37 (3) ◽  
pp. 531-540
Author(s):  
P.S. Yadav ◽  
Rajesh Purohit ◽  
Anil Kothari ◽  
R. S. Rajput
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Thermal Properties ◽  
Hybrid Composite ◽  
Hybrid Composites ◽  
Mechanical And Thermal Properties ◽  
Nano Sio2 ◽  
Kevlar Fiber ◽  
Heat Deflection Temperature ◽  
Scanning Electron

The aim of the current investigation is an analysis of the mechanical and thermal properties of epoxy/ nano-silica/ Kevlar fiber hybrid composites. The ultrasonic vibration-assisted hand layup process was used for the preparation of composite with different weight percentages (1%, 2%, 3%, and 4%) of Nano SiO2 particles and 2 layers of the Kevlar fiber. For the evolution of mechanical properties tensile tests, hardness tests, impact tests, and flexural tests were done. For evaluation of morphological analysis Field Emission-Scanning Electron Microscopy, X-RD, and FT-IR tests were performed. A heat deflection temperature test was performed for the evaluation of the thermal characteristic of the hybrid composite. The results show the improvement of mechanical and thermal properties of the hybrid composite with increasing wt.% of nano SiO2 particles in the hybrid composites. As per the observation of experimental results, the Field Emission-Scanning Electron Microscopy,Fourier Transform Infrared Spectroscopy, and X-ray diffraction test also show the enhancement of surface morphology and chemical structure of hybrid composites. The heat diffraction test shows the improvement of thermal resistance and heat absorption capability.As per the observation of experimental results, the tensile strength, hardness, and impact strength increased up to 98%, 16%, and 42% respectively. The flexural test shows the improvement of flexural modulus and stresses 46% and 35% respectively. The heat deflection temperature of hybrid composite improves up to 30%.

Tuning the Ablation, Thermal and Mechanical Characteristics of Phenolic Resin Reinforced EPDM Ultra-High Temperature Insulation

2021 ◽  
Vol 875 ◽  
pp. 88-95
Author(s):  
Sadia Sagar Iqbal ◽  
Tasawer Shahzad Ahmad ◽  
Arshad Bashir ◽  
Ali Bahadar ◽  
Farzana Siddique
Keyword(s):  
Electron Microscopy ◽  
Thermal Conductivity ◽  
Scanning Electron Microscopy ◽  
Mechanical Characteristics ◽  
Phenolic Resin ◽  
Ethylene Propylene Diene Monomer ◽  
Polymer Melting ◽  
Base Matrix ◽  
Ablation Characteristics ◽  
Scanning Electron

The present research reports the influences of variant phenolic resin concentrations on the thermo-mechanical and ablation characteristics of ethylene propylene diene monomer (EPDM) elastomer. Backface temperature acclivity (BTA), charring rates, and insulation indexes were executed for the fabricated composite specimens. It was noticed that BTA was enhanced while linear/radial/mass ablation rates were significantly diminished with increasing concentration of phenolic resin (PR) in base matrix (elastomeric polymer). The composite (30wt%PR/EPDM) has 25% high thermal endurance compared to virgin EPDM composite. Thermal conductivity was increased with increasing PR to EPDM ratio. PR incorporation has remarkably enhanced the ultimate tensile strength of the EPDM elastomer. An efficient improvement in elastomeric hardness was also observed with increasing PR contents in EPDM matrix. Scanning Electron Microscopy (SEM) results showed the porosity generation and polymer melting during ablation.

Adhesion of Steel and PMMA by Means of Laser Radiation

2017 ◽  
Vol 885 ◽  
pp. 61-66 ◽  
Author(s):  
Andor Bauernhuber ◽  
Tamás Markovits ◽  
László Trif ◽  
Ágnes Csanády
Keyword(s):  
Electron Microscopy ◽  
Mass Spectrometry ◽  
Scanning Electron Microscopy ◽  
Plastic Material ◽  
Bubble Formation ◽  
Polymeric Materials ◽  
Good Adhesion ◽  
Novel Method ◽  
Scanning Electron

As the utilization of plastics is growing in our devices, their joining with other structural materials, like metals is more and more necessary. A novel method for joining polymeric materials and metals is the laser assisted metal plastic joining. The method is in focus of several researches. However, the mechanism of joint formation is not described sufficiently yet. In this study, the adhesion between structural steel and PMMA plastic and the phenomena of bubble formation is investigated. Scanning electron microscopy (SEM), thermogravimetry and mass spectrometry (TG-MS) were used to analyze joining interfaces and changes in the plastic material. Results show good adhesion between the mentioned materials and the important role of bubbles in the evolution of joining force.

Wavelet Transform and Bispectrum Applied to Acoustic Emission Signals from Adherence Scratch-Tests on Corroded Galvanized Coatings

2006 ◽  
Vol 13-14 ◽  
pp. 83-88 ◽  
Author(s):  
Antolino Gallego ◽  
Jose F. Gil ◽  
J.M. Vico ◽  
Enrique Díaz Barriga-Castro ◽  
J.E. Ruzzante ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Acoustic Emission ◽  
Visual Inspection ◽  
Fracture Mechanisms ◽  
X Ray Diffraction ◽  
X Ray ◽  
Galvanized Coatings ◽  
Scratch Tests ◽  
Ae Signals ◽  
Scanning Electron

Wavelet analysis and bispectrum was applied to Acoustic Emission (AE) signals from scratch tests on corroded hot-dip galvanized samples in order to achieve the detection of corrosion products in pieces non reachable by visual inspection. AE signals were correlated with the fracture mechanisms occurring during scratch tests, while the contact force increased. Results were corroborated by Scanning Electron Microscopy (SEM), Energy Dispersive X-ray spectroscopy (EDX) and X-Ray Diffraction (XRD).

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