The Impact of Thermal Degradation on Properties of Electrical Machine Winding Insulation Material

AbstractHere, an engineered tunneling layer enhanced photocurrent multiplication through the impact ionization effect was proposed and experimentally demonstrated on the graphene/silicon heterojunction photodetectors. With considering the suitable band structure of the insulation material and their special defect states, an atomic layer deposition (ALD) prepared wide-bandgap insulating (WBI) layer of AlN was introduced into the interface of graphene/silicon heterojunction. The promoted tunneling process from this designed structure demonstrated that can effectively help the impact ionization with photogain not only for the regular minority carriers from silicon, but also for the novel hot carries from graphene. As a result, significantly enhanced photocurrent as well as simultaneously decreased dark current about one order were accomplished in this graphene/insulation/silicon (GIS) heterojunction devices with the optimized AlN thickness of ~15 nm compared to the conventional graphene/silicon (GS) devices. Specifically, at the reverse bias of −10 V, a 3.96-A W−1 responsivity with the photogain of ~5.8 for the peak response under 850-nm light illumination, and a 1.03-A W−1 responsivity with ∼3.5 photogain under the 365 nm ultraviolet (UV) illumination were realized, which are even remarkably higher than those in GIS devices with either Al2O3 or the commonly employed SiO2 insulation layers. This work demonstrates a universal strategy to fabricate broadband, low-cost and high-performance photo-detecting devices towards the graphene-silicon optoelectronic integration.

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The Effect of External Conditions on Ignition Temperature of Thermoplastic Polyurethane Elastomers

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.838-841.14 ◽

2013 ◽

Vol 838-841 ◽

pp. 14-17

Author(s):

Ivana Turekova ◽

Zuzana Szabova ◽

Tomas Chrebet ◽

Jozef Harangozo

Keyword(s):

Thermal Degradation ◽

Ignition Temperature ◽

Thermoplastic Polyurethane ◽

Thermo Gravimetric Analysis ◽

Gravimetric Analysis ◽

Polyurethane Elastomers ◽

External Conditions ◽

Thermoplastic Polyurethane Elastomers ◽

The Impact

The paper reports a study of the impact of moisture and age of pellets, as well as an external condition, on the thermal degradation of the thermoplastic polyurethane elastomers. Because thermoplastic polyurethane elastomers are hydroscopic polymer, moisture will have a significant impact on thermal degradation. For determination of the effect of moisture and age were used the thermo gravimetric analysis, differential scanning calorimeter and ISO STN 871: Plastics. Determination of ignition temperature using a hot-air furnace.

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Characteristics and mechanical properties changes due to incorporation of aloe vera in polyethylene-based film

Scientific Research Journal ◽

10.24191/srj.v17i2.9837 ◽

2020 ◽

Vol 17 (2) ◽

pp. 61

Author(s):

Siti Fatma Abd Karim ◽

Junaidah Binti Jai ◽

Ku Halim Ku Hamid ◽

Abdul Wafi Abdul Jalil

Keyword(s):

Mechanical Properties ◽

Thermal Degradation ◽

Aloe Vera ◽

Functional Materials ◽

Chain Structure ◽

Substantial Effect ◽

Scanning Calorimetry ◽

Degradation Temperature ◽

And Performance ◽

The Impact

Non-degradable properties of polyethylene (PE) films due to long-chain structure cause increment of solid waste plastic. Many researchers, with different purposes, have studied the incorporation of functional materials to PE. Studying the impact of incorporation of aloe vera (AV) into PE films in terms of its characteristic and mechanical properties is the main objective of this paper. The films were prepared using melt-blending and hot press technique. The characterization assessed for the PE and PE-AV films were spectroscopy, crystalline phase, thermal analysis and performance of mechanical properties of the sample. The functional group detected in spectroscopy studied did not show any changes for PE film or PE with the presence of AV. Lower thermal degradation temperature (Td) obtained for PE-AV3 while others film found no significant changes of Td value and only one peak of thermal degradation occurred for all film. The same goes to the analysis obtained from differential scanning calorimetry (DSC) data. However, the crystalline structure displayed momentous peak changes for PE with AV. The highest tensile strength (TS) obtained by PE-AV3, at once developing highest value of Young’s modulus (YM), modulus of resilience (UE) and modulus of toughness (UT). A certain amount of AV has substantial effect on changing the polymeric structure especially improving the mechanical properties of PE film. Therefore, AV has potential to become an additive for developing a new partially degradable PE film.

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Smart-Sensors to Estimate Insulation Health in Induction Motors via Analysis of Stray Flux

Energies ◽

10.3390/en12091658 ◽

2019 ◽

Vol 12 (9) ◽

pp. 1658 ◽

Cited By ~ 7

Author(s):

Israel Zamudio-Ramirez ◽

Roque Alfredo Osornio-Rios ◽

Miguel Trejo-Hernandez ◽

Rene de Jesus Romero-Troncoso ◽

Jose Alfonso Antonino-Daviu

Keyword(s):

Induction Motors ◽

Early Stage ◽

Industrial Sector ◽

Smart Sensors ◽

Discrete Wavelet ◽

Electrical Machine ◽

Smart Sensor ◽

Time Frequency ◽

Essential Components ◽

Winding Insulation

Induction motors (IMs) are essential components in industrial applications. These motors have to perform numerous tasks under a wide variety of conditions, which affects performance and reliability and gradually brings faults and efficiency losses over time. Nowadays, the industrial sector demands the necessary integration of smart-sensors to effectively diagnose faults in these kinds of motors before faults can occur. One of the most frequent causes of failure in IMs is the degradation of turn insulation in windings. If this anomaly is present, an electric motor can keep working with apparent normality, but factors such as the efficiency of energy consumption and mechanical reliability may be reduced considerably. Furthermore, if not detected at an early stage, this degradation could lead to the breakdown of the insulation system, which could in turn cause catastrophic and irreversible failure to the electrical machine. This paper proposes a novel methodology and its application in a smart-sensor to detect and estimate the healthiness of the winding insulation in IMs. This methodology relies on the analysis of the external magnetic field captured by a coil sensor by applying suitable time-frequency decomposition (TFD) tools. The discrete wavelet transform (DWT) is used to decompose the signal into different approximation and detail coefficients as a pre-processing stage to isolate the studied fault. Then, due to the importance of diagnosing stator winding insulation faults during motor operation at an early stage, this proposal introduces an indicator based on wavelet entropy (WE), a single parameter capable of performing an efficient diagnosis. A smart-sensor is able to estimate winding insulation degradation in IMs using two inexpensive, reliable, and noninvasive primary sensors: a coil sensor and an E-type thermocouple sensor. The utility of these sensors is demonstrated through the results obtained from analyzing six similar IMs with differently induced severity faults.

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The Evolving E-cigarette: Comparative Chemical Analyses of E-cigarette Vapor and Cigarette Smoke

Frontiers in Toxicology ◽

10.3389/ftox.2020.586674 ◽

2020 ◽

Vol 2 ◽

Author(s):

Anthony Cunningham ◽

Kevin McAdam ◽

Jesse Thissen ◽

Helena Digard

Keyword(s):

Thermal Decomposition ◽

Thermal Degradation ◽

Benzoic Acid ◽

Cigarette Smoke ◽

Iron Alloy ◽

Decomposition Products ◽

Nickel Iron ◽

Degradation Reactions ◽

Nickel Iron Alloy ◽

The Impact

Background: E-cigarette designs, materials, and ingredients are continually evolving, with cotton wicks and diverse coil materials emerging as the popular components of atomisers. Another recent development is the use of nicotine salts in e-liquids to replicate the form of nicotine found in cigarette smoke, which may help cigarette smokers to transition to e-cigarettes. However, scientific understanding of the impact of such innovations on e-cigarette aerosol chemistry is limited.Methods: To address these knowledge gaps, we have conducted a comparative study analyzing relevant toxicant emissions from five e-cigarettes varying in wick, atomiser coil, and benzoic acid content and two tobacco cigarettes, quantifying 97 aerosol constituents and 84 smoke compounds, respectively. Our focus was the potential for benzoic acid in e-liquids and cotton wicks to form aerosol toxicants through thermal degradation reactions, and the potential for nickel–iron alloy coils to catalyze degradation of aerosol formers. In addition, we analyzed e-cigarette emissions for 19 flavor compounds, thermal decomposition products, and e-liquid contaminants that the FDA has recently proposed adding to the established list of Harmful and Potentially Harmful Constituents (HPHCs) in tobacco products.Results: Analyses for benzene and phenol showed no evidence of the thermal decomposition of benzoic acid in the e-cigarettes tested. Measurements of cotton decomposition products, such as carbonyls, hydrocarbons, aromatics, and PAHs, further indicated that cotton wicks can be used without thermal degradation in suitable e-cigarette designs. No evidence was found for enhanced thermal decomposition of propylene glycol or glycerol by the nickel–iron coil. Sixteen of the 19 FDA-proposed compounds were not detected in the e-cigarettes. Comparing toxicant emissions from e-cigarettes and tobacco cigarettes showed that levels of the nine WHO TobReg priority cigarette smoke toxicants were more than 99% lower in the aerosols from each of five e-cigarettes as compared with the commercial and reference cigarettes.Conclusions: Despite continuing evolution in design, components and ingredients, e-cigarettes continue to offer significantly lower toxicant exposure alternatives to cigarette smoking.

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Impact resistance of external thermal insulation systems

MATEC Web of Conferences ◽

10.1051/matecconf/201816308004 ◽

2018 ◽

Vol 163 ◽

pp. 08004 ◽

Cited By ~ 1

Author(s):

Ewa Sudoł ◽

Dawid Dębski ◽

Renata Zamorowska ◽

Barbara Francke

Keyword(s):

Thermal Insulation ◽

Impact Resistance ◽

Experimental Program ◽

Insulation Material ◽

Test Results ◽

Composite Systems ◽

Factors Influencing ◽

Insulation Systems ◽

The Impact ◽

Fibre Mesh

In the paper the results of an experimental program intended to determine factors influencing the impact resistance of the External Thermal Insulation Composite Systems (ETICS) were presented. For the research the systems based on polystyrene have been chosen. The insulation material was faced with a rendering consisting of base coat reinforced with standard or armored glass fibre mesh and silicone or silicone-silicate binders as finishing coats. The influence of various renderings components was evaluated with respect to resistance to hard body impact and resistance to hail. The test results were discussed in the context of the possible impact level on ETICS in use.

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Low-velocity impact response of wood-strand sandwich panels and their components

Holzforschung ◽

10.1515/hf-2017-0169 ◽

2018 ◽

Vol 72 (8) ◽

pp. 681-689 ◽

Cited By ~ 5

Author(s):

Mostafa Mohammadabadi ◽

Vikram Yadama ◽

LiHong Yao ◽

Debes Bhattacharyya

Keyword(s):

Energy Absorption ◽

Impact Energy ◽

Failure Modes ◽

Sandwich Panels ◽

Low Velocity Impact ◽

Insulation Material ◽

Low Velocity ◽

Velocity Impact ◽

Section Modulus ◽

The Impact

AbstractProfiled hollow core sandwich panels (SPs) and their components (outer layers and core) were manufactured with ponderosa and lodgepole pine wood strands to determine the effects of low-velocity impact forces and to observe their energy absorption (EA) capacities and failure modes. An instrumented drop weight impact system was applied and the tests were performed by releasing the impact head from 500 mm for all the specimens while the impactors (IMPs) were equipped with hemispherical and flat head cylindrical heads. SPs with cavities filled with a rigid foam insulation material (SPfoam) were also tested to understand the change in EA behavior and failure mode. Failure modes induced by both IMPs to SPs were found to be splitting, perforating, penetrating, core crushing and debonding between the core and the outer layers. SPfoams absorbed 26% more energy than unfilled SPs. SPfoams with urethane foam suffer less severe failure modes than SPs. SPs in a ridge-loading configuration absorbed more impact energy than those in a valley-loading configuration, especially when impacted by a hemispherical IMP. Based on the results, it is evident that sandwich structure is more efficient than a solid panel concerning impact energy absorption, primarily due to a larger elastic section modulus of the core’s corrugated geometry.

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