IET Nanodielectrics最新文献

{"title":"Impact of adding activated bentonite to thermally aged ester-based TiO2 nanofluids on insulation performance","authors":"A. J. Amalanathan,&nbsp;N. Harid,&nbsp;H. Griffiths,&nbsp;R. Sarathi","doi":"10.1049/nde2.12010","DOIUrl":"10.1049/nde2.12010","url":null,"abstract":"<p>The authors report the key findings from an experimental study that explored the use of activated bentonite for the reclamation of thermally aged ester-based transformer nanofluids to improve their insulation performance. Bentonite activated with acid treatment caused an increase in the specific surface area and pore volume of bentonite compared to the bentonite sample before treatment, thus imparting an improved adsorption capability. Physico-chemical diagnostic studies were carried out to characterise the activated bentonite. The insulation performance of the reclaimed natural ester and nano-filled ester fluid samples was assessed by measuring the corona inception voltage and breakdown voltage of each fluid sample, apart form measuring the flow electrification current using the spinning disk method. The results revealed that the reclamation process improved the corona inception voltage, dissipation factor and the breakdown voltage of the base ester fluid sample due to attraction of carbon particles to activated bentonite, but no significant variation was observed with nanofluids due to the depletion of the electrical double layer. The flow electrification current of ester and ester nanofluids reduced after treatment with activated bentonite, may be attributed to the interaction between copper and bentonite that alters the double layer formation responsible for the separation of charges.</p>","PeriodicalId":36855,"journal":{"name":"IET Nanodielectrics","volume":"4 2","pages":"63-74"},"PeriodicalIF":2.7,"publicationDate":"2021-03-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ietresearch.onlinelibrary.wiley.com/doi/epdf/10.1049/nde2.12010","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45861256","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Nickel-cobalt-zinc ferrite nanoparticles for radio-frequency/terahertz frequency-selective surface application","authors":"Meenakshi Arya,&nbsp;Mayuri N. Gandhi,&nbsp;Shriganesh S. Prabhu,&nbsp;Venu Gopal Achanta,&nbsp;Siddhartha P Duttagupta","doi":"10.1049/nde2.12004","DOIUrl":"10.1049/nde2.12004","url":null,"abstract":"<p>Nanoparticles of Ni_0.5Co_0.2Zn_0.3Fe₂O₄ were prepared using the sol-gel combustion route. The nanoparticles were characterised by x-ray diffraction to confirm single-phase formation in a cubic spinel structure. Micro- and nanostructural analyses were carried out using field emission-scanning electron microscopy and field emission-transmission electron microscopy, respectively. A planetary ball milling technique was used to grind the powder into nanoparticles; the average particle size was 64 nm. Energy-dispersive X-ray spectroscopy was used to determine the atomic composition of the sample. Radio-frequency characteristics were recorded for dielectric measurement in a frequency range of 1 Hz to 15 MHz using a broadband dielectric spectrometer. Terahertz (THz) time-domain spectroscopy was performed to study THz-optical parameters such as refractive index, dielectric constant, and conductivity at room temperature in a frequency range of 0.3−2.2 THz using an indigenously developed THz time-domain spectroscopy setup. The magnetic properties of the sample were studied using a SQUID vibrating sample magnetometer under an applied magnetic field of ±10 kOe. An examination of M-H loops revealed that the saturation magnetization <math>\u0000 <mrow>\u0000 <mo>(</mo>\u0000 <msub>\u0000 <mi>M</mi>\u0000 <mi>s</mi>\u0000 </msub>\u0000 <mo>)</mo>\u0000 </mrow></math>, remanent magnetization <math>\u0000 <mrow>\u0000 <mo>(</mo>\u0000 <msub>\u0000 <mi>M</mi>\u0000 <mi>r</mi>\u0000 </msub>\u0000 <mo>)</mo>\u0000 </mrow></math> and coercivity <math>\u0000 <mrow>\u0000 <mo>(</mo>\u0000 <msub>\u0000 <mi>H</mi>\u0000 <mi>c</mi>\u0000 </msub>\u0000 <mo>)</mo>\u0000 </mrow></math> increased with an increase in temperature from 300 to 50 K.</p>","PeriodicalId":36855,"journal":{"name":"IET Nanodielectrics","volume":"4 3","pages":"98-106"},"PeriodicalIF":2.7,"publicationDate":"2021-02-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ietresearch.onlinelibrary.wiley.com/doi/epdf/10.1049/nde2.12004","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44187405","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Regulating dielectric performances of Poly(vinylidene fluoride) nanocomposites by individually controlling shell thickness of Core@Double-Shells structured nanowires","authors":"Minhao Yang,&nbsp;Zhi-Yong Xue,&nbsp;Zhi-Min Dang,&nbsp;Yang Shen,&nbsp;Paul Haghi-Ashtiani,&nbsp;Delong He,&nbsp;Jian Xu,&nbsp;Jinbo Bai","doi":"10.1049/nde2.12003","DOIUrl":"10.1049/nde2.12003","url":null,"abstract":"<p>The synthesis of core@double-shells structured TiO₂@C@SiO₂ nanowires (NWs) with variable thickness of carbon inner shell and SiO₂ outer shell was achieved by individually controlling the chemical vapour deposition time and amount of silicon precursor added in the sol–gel synthesis. The resultant TiO₂@C@SiO₂ NWs filled nanocomposites exhibited an excellent dielectric performance with simultaneously improved dielectric constant and suppressed dielectric loss, which could be further regulated by individually controlling the carbon inner shell and SiO₂ outer shell thickness. More importantly, the influences of the conductive carbon inner shell and insulated SiO₂ outer shell thickness on the dielectric performance of nanocomposites were clearly revealed. The increase of the conductive carbon inner shell thickness would lead to an increase in dielectric constant and loss of nanocomposites, while the insulated SiO₂ outer shell exhibited a totally opposite law that the dielectric constant and loss of nanocomposites decrease with increasing SiO₂ outer shell thickness. Numerical simulations were also carried out to theoretically verify the relationship between the dielectric loss and SiO₂ outer shell thickness. This promising controllable multi-shell structure could be extended to a variety of hybrids to develop high-performance dielectric nanocomposites.</p>","PeriodicalId":36855,"journal":{"name":"IET Nanodielectrics","volume":"4 1","pages":"11-20"},"PeriodicalIF":2.7,"publicationDate":"2021-02-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ietresearch.onlinelibrary.wiley.com/doi/epdf/10.1049/nde2.12003","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44901654","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Novel failure mechanism of nanoscale mesa-type avalanche photodiodes under harsh environmental stresses","authors":"Jack Jia-Sheng Huang,&nbsp;HsiangSzu Chang,&nbsp;Emin Chou,&nbsp;Yu-Heng Jan,&nbsp;Jin-Wei Shi","doi":"10.1049/nde2.12001","DOIUrl":"10.1049/nde2.12001","url":null,"abstract":"<p>Avalanche photodiode (APD) is an indispensable receiver component because of its high bandwidth and low noise performance. Recently, APD reliability, under harsh environmental stresses such as high heat and humidity, has drawn great interest in the applications of passive optical network, wireless, military, and free space optics. The authors study the APD degradation under the harsh environment of high humidity and high bias. The failure morphology through cross-sectional scanning electron microscopy is shown, and a new moisture degradation model based on electrochemical oxidation to account for the failure mechanism is developed.</p>","PeriodicalId":36855,"journal":{"name":"IET Nanodielectrics","volume":"4 1","pages":"21-26"},"PeriodicalIF":2.7,"publicationDate":"2021-02-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ietresearch.onlinelibrary.wiley.com/doi/epdf/10.1049/nde2.12001","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47101234","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Enhanced electromechanical performance through chemistry graft copper phthalocyanine to siloxane-modified polyurethane and interpenetrate with siloxane silicon rubber as composite actuator material","authors":"Tingting Huang,&nbsp;Bolei Yuan,&nbsp;Jun Tang,&nbsp;Yunhe Zhang","doi":"10.1049/nde2.12008","DOIUrl":"10.1049/nde2.12008","url":null,"abstract":"<p>Researchers are devoted to developing dielectric elastomers (DEs) with excellent electromechanical properties as an artificial muscle material. The authors report a new class of semi-interpenetrating network (semi-IPN) composites that contains siloxane-modified linear polyurethane (PU) and silicone rubber through reasonable design of polymer structure. The organic-filler copper phthalocyanine (CuPc) is chemically grafted into the semi-interpenetrating network as a cross-linking point and exhibits excellent dispersibility in the matrix. The various properties of the obtained composite films are also evaluated. The dielectric constant (8.65 at 1 kHz) and maximum actuation strain at 30 MV m⁻¹ (5.32%) are significantly higher than those of semi-IPN composites.</p>","PeriodicalId":36855,"journal":{"name":"IET Nanodielectrics","volume":"4 1","pages":"38-44"},"PeriodicalIF":2.7,"publicationDate":"2021-02-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ietresearch.onlinelibrary.wiley.com/doi/epdf/10.1049/nde2.12008","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48092546","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Integrated multifunctional properties of polypropylene composites by employing three-dimensional flower-like MgO with hierarchical surface morphology","authors":"Jun-Wei Zha,&nbsp;Qi Cheng,&nbsp;Jin-Tao Zhai,&nbsp;Xingming Bian,&nbsp;George Chen,&nbsp;Zhi-Min Dang","doi":"10.1049/nde2.12006","DOIUrl":"10.1049/nde2.12006","url":null,"abstract":"<p>Polymer nanocomposites have attracted increased attention for use in the field of high-voltage direct current (HVDC) cable insulation. To study the use of polymer nanocomposites for this purpose, 3D flower-like MgO (flower-MgO) particles with hierarchical surface morphology are first synthesised. Polypropylene (PP) was simultaneously mixed with styrene-(ethylene-co-butylene)-styrene triblock copolymer (SEBS) and flower-MgO to obtain PP/SEBS/flower-MgO composites. The microstructural, thermal, electrical, and mechanical properties of the obtained nanocomposites were then studied in detail. The results showed that flower-MgO particles loaded at low concentration were well dispersed in the PP/SEBS matrix. The incorporation of flower-MgO particles has been found to significantly suppress the injection of homocharges and strengthen the ability to release the charge, thus containing accumulation of the space charge. The DC breakdown strength of PP/SEBS/flower-MgO composites was increased to 323 MV/m. Meanwhile, the tensile strength and elongation at break of the obtained composites was improved by loading 0.5 phr flower-MgO because of the synergistic toughening effects of SEBS and MgO. The investigation demonstrates the immense potential to replace nonrecyclable cross-linked polyethylene as an HVDC cable insulating material.</p>","PeriodicalId":36855,"journal":{"name":"IET Nanodielectrics","volume":"4 1","pages":"27-37"},"PeriodicalIF":2.7,"publicationDate":"2021-02-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ietresearch.onlinelibrary.wiley.com/doi/epdf/10.1049/nde2.12006","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44619382","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Dielectric performance of magnetic nanoparticles-based ester oil","authors":"Qasim Khan,&nbsp;Vineet Singh,&nbsp;Furkan Ahmad,&nbsp;Asfar Ali Khan","doi":"10.1049/nde2.12005","DOIUrl":"10.1049/nde2.12005","url":null,"abstract":"Furkan Ahmad, Centre for Automotive Research and Tribology (CART), Indian Institute of Technology, Delhi, India. Email: furkanahmad@zhcet.ac.in, ahmdfurkan@iitd. ac.in Abstract Nanotechnology has been applied in the electrical industry for the enhancement of insulation properties. The compactness of the electrical machines has resulted in the requirement and creation of next‐generation insulating fluid with inflated dielectric properties. In this study, the magnetic nanoparticles are used in different concentrations to form stable nanofluids comprising ester‐based oils and two different electrode structures. The host fluids are synthetic ester oil and rapeseed oil, and magnetic nanoparticles used are iron (II, III) oxide, cobalt (II, III) oxide, and iron phosphide. Furthermore, the breakdown tests are analysed using Weibull statistical distribution.","PeriodicalId":36855,"journal":{"name":"IET Nanodielectrics","volume":"4 2","pages":"45-52"},"PeriodicalIF":2.7,"publicationDate":"2021-02-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ietresearch.onlinelibrary.wiley.com/doi/epdf/10.1049/nde2.12005","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43660287","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Time-domain characterisation of epoxy-based barium titanate nanocomposites","authors":"Romana Zafar,&nbsp;Nandini Gupta","doi":"10.1049/nde2.12002","DOIUrl":"10.1049/nde2.12002","url":null,"abstract":"<p>In this article, the dielectric response of epoxy resin and epoxy-based barium titanate (BaTiO₃) nanocomposites is characterised in the time-domain, based on polarisation and depolarisation current measurements. The aim of this article is to understand the dominant polarisation mechanisms in neat epoxy and its nanocomposites and validate the findings in frequency-domain spectroscopy (FDS). The effect of various parameters on the dielectric response of the material is investigated to this end, namely, polarisation–depolarisation time, electrode material, electric field and specimen thickness. The effect of pre-processing the nano-particles before use is also studied. In order to validate the findings of FDS, time-domain spectroscopy (TDS) of neat epoxy and its nanocomposites is performed.</p>","PeriodicalId":36855,"journal":{"name":"IET Nanodielectrics","volume":"4 1","pages":"1-10"},"PeriodicalIF":2.7,"publicationDate":"2021-02-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ietresearch.onlinelibrary.wiley.com/doi/epdf/10.1049/nde2.12002","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48014538","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Structure design boosts concomitant enhancement of permittivity, breakdown strength, discharged energy density and efficiency in all-organic dielectrics","authors":"Zhenkang Dan,&nbsp;Weibin Ren,&nbsp;Mengfan Guo,&nbsp;Zhonghui Shen,&nbsp;Tao Zhang,&nbsp;Jianyong Jiang,&nbsp;Cewen Nan,&nbsp;Yang Shen","doi":"10.1049/iet-nde.2020.0034","DOIUrl":"10.1049/iet-nde.2020.0034","url":null,"abstract":"<p>Polymer-based nanocomposites with excellent flexibility and intrinsic high breakdown strength are promising candidates for high energy density capacitors compared to ceramics counterparts. However, their energy density is relatively low due to the trade-off between permittivity and breakdown strength. In this work, the authors proposed a ferroconcrete-like structure for all-organic nanocomposites via combinatorial electrospinning and hot-pressing method. In this structure, polymethyl methacrylate (PMMA) serves as matrix while poly(vinylidene fluoride-co-hexafluoropropylene) (P(VDF-HFP)) serves as reinforcement phase. This novel structure is highly effective in breaking the paradox of improved discharged energy density with decreased efficiency, as evidenced by the concurrently improved discharged energy density (∼12.15 J/cm³ compared to 8.82 J/cm³ of the matrix) and efficiency (∼81.7% compared to 76.8% of the matrix). Compared to conventional blending composite films, samples with ferroconcrete-like structure exhibit higher permittivity, breakdown strength, discharged energy density and efficiency. The superior energy storage performance is attributed to large aspect ratio P(VDF-HFP) fibres distributed perpendicularly to the external field, which brings about the extra enhancement of permittivity. Besides, mechanical properties are improved and restriction on carrier motion is facilitated, leading to enhanced breakdown strength and suppressed conduction. This work provides a new way to design dielectric composite for high energy density and efficiency applications.</p>","PeriodicalId":36855,"journal":{"name":"IET Nanodielectrics","volume":"3 4","pages":"147-155"},"PeriodicalIF":2.7,"publicationDate":"2020-12-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ietresearch.onlinelibrary.wiley.com/doi/epdf/10.1049/iet-nde.2020.0034","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42127845","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Titania-based transformer nanofluid: a study on the synthesis for enhanced breakdown strength and its humidity ageing","authors":"S. Raja,&nbsp;G. Koperundevi","doi":"10.1049/iet-nde.2020.0014","DOIUrl":"10.1049/iet-nde.2020.0014","url":null,"abstract":"<p>Researches on the transformer oil-based nanofluids to determine its suitability for replacing the conventional liquid insulation has been consistently happening for more than a decade. Yet, to prepare an optimum blend of transformer oil-based nanofluid with the stability compliance and superior breakdown (BD) characteristics is still a key issue to be addressed. So to achieve the higher BD voltages (BDVs) with good stability, the nanoparticle and surfactant weights dispersed in the oil should be optimised to at least possible critical levels. In this work, dielectric BD characteristic of mineral oil dispersed with TiO₂ nanoparticle and surfactant cetyl trimethyl ammonium bromide (CTAB) is been studied with the applied AC and DC high voltages, which is termed as titania-based transformer nanofluid (TTNF) for this study. Series of TTNF samples were synthesised with different weights of TiO₂ nanoparticle and CTAB, and the partial discharge inception voltage, AC and DC BDV were experimented to ascertain the optimum concentration level. Results show that the AC and DC BDV enhanced up to 36.23 and 43.07%, respectively, for the TTNF prepared with 0.00562 wt% of TiO₂ and its 1% weight of CTAB, which was stable for around eight weeks.</p>","PeriodicalId":36855,"journal":{"name":"IET Nanodielectrics","volume":"3 4","pages":"138-146"},"PeriodicalIF":2.7,"publicationDate":"2020-11-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ietresearch.onlinelibrary.wiley.com/doi/epdf/10.1049/iet-nde.2020.0014","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44727443","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}