Pub Date : 1985-09-01DOI: 10.1109/ISE.1985.7341516
T. Eish, F. Youssef
Experimental investigations on treeing breakdown characteristics of cross-Linked polyethylene (XLPE) cables immersed in transformer oil are introduced and discussed in this paper. The study has been done under alternating (50 Hz) and direct voltage stresses. Thereby, the effect of duration, waveform and polarity of the applied voltage as well as the temperature rise of oil, the size of cable and the diameter of needle electrode on treeing breakdown are included.
{"title":"Factor affecting the treeing breakdown phenomena of XLPE cables","authors":"T. Eish, F. Youssef","doi":"10.1109/ISE.1985.7341516","DOIUrl":"https://doi.org/10.1109/ISE.1985.7341516","url":null,"abstract":"Experimental investigations on treeing breakdown characteristics of cross-Linked polyethylene (XLPE) cables immersed in transformer oil are introduced and discussed in this paper. The study has been done under alternating (50 Hz) and direct voltage stresses. Thereby, the effect of duration, waveform and polarity of the applied voltage as well as the temperature rise of oil, the size of cable and the diameter of needle electrode on treeing breakdown are included.","PeriodicalId":6451,"journal":{"name":"1985 5th International Symposium on Electrets (ISE 5)","volume":"79 1","pages":"410-415"},"PeriodicalIF":0.0,"publicationDate":"1985-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83242033","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1985-09-01DOI: 10.1109/ISE.1985.7341457
B. Gross
This paper describes aspects of research on dielectrics and electrets carried out by the author over the last 50 years, in an attempt to show the systematics of its development and the logical relation between its successive steps. Starting with dielectric absorption, it covers open-circuit behavior of dielectrics, thermally stimulated currents, Paschen breakdown and its effects on the performance of the induction plate method, and the superposition of free surface charge and dielectric volume polarisation. The two-charge theory appears as the result of a straightforward application of the basic charge and field equations of electrostatics, without the introduction of a specific model. Theoretical results are developed on hand of simple experiments most of them performed with Carnauba wax. Recent research has added a wealth of detailed information, but still leaves open many important questions.
{"title":"Electret research — Stages in its development","authors":"B. Gross","doi":"10.1109/ISE.1985.7341457","DOIUrl":"https://doi.org/10.1109/ISE.1985.7341457","url":null,"abstract":"This paper describes aspects of research on dielectrics and electrets carried out by the author over the last 50 years, in an attempt to show the systematics of its development and the logical relation between its successive steps. Starting with dielectric absorption, it covers open-circuit behavior of dielectrics, thermally stimulated currents, Paschen breakdown and its effects on the performance of the induction plate method, and the superposition of free surface charge and dielectric volume polarisation. The two-charge theory appears as the result of a straightforward application of the basic charge and field equations of electrostatics, without the introduction of a specific model. Theoretical results are developed on hand of simple experiments most of them performed with Carnauba wax. Recent research has added a wealth of detailed information, but still leaves open many important questions.","PeriodicalId":6451,"journal":{"name":"1985 5th International Symposium on Electrets (ISE 5)","volume":"5 5","pages":"9-46"},"PeriodicalIF":0.0,"publicationDate":"1985-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"72598033","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1985-09-01DOI: 10.1109/ISE.1985.7341459
G. Ferreira, L. N. Oliveira, O. N. Oliveira, J. Giacometti
We discuss a simple rule relating the corona current incident upon a polymer film in a vibrating corona triode to the discontinuity in the displacement current across the sample when the corona is turned off. By analyzing experimental results, we show that this relation, equivalent to the equation of continuity, often seems violated; we prove the limited resolution of voltmeters responsible for the discrepancy. In addition, we show that a violation of the rule indicates partial, direct injection of the corona current into the sample.
{"title":"A current conservation relation experimentally checked","authors":"G. Ferreira, L. N. Oliveira, O. N. Oliveira, J. Giacometti","doi":"10.1109/ISE.1985.7341459","DOIUrl":"https://doi.org/10.1109/ISE.1985.7341459","url":null,"abstract":"We discuss a simple rule relating the corona current incident upon a polymer film in a vibrating corona triode to the discontinuity in the displacement current across the sample when the corona is turned off. By analyzing experimental results, we show that this relation, equivalent to the equation of continuity, often seems violated; we prove the limited resolution of voltmeters responsible for the discrepancy. In addition, we show that a violation of the rule indicates partial, direct injection of the corona current into the sample.","PeriodicalId":6451,"journal":{"name":"1985 5th International Symposium on Electrets (ISE 5)","volume":"9 1","pages":"53-58"},"PeriodicalIF":0.0,"publicationDate":"1985-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"72832983","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1985-09-01DOI: 10.1109/ISE.1985.7341486
J. Gil-Zambrano, C. Juhasz
The TSD technique has been used to study the α-relaxation in Nylon terpolymer films. A well isolated peak observed at about 60 °C in the TSD spectrum suggests the onset of low frequency molecular motions in the polymer. Experimental results indicate that the induced polarization is due to dipole alingment. TSP experiments give a peak characterized by the same position and height as the TSD peak. Tq determined by DTA lies in the region in which the α-peak occurs, a.c. measurements also reveal a loss peak in the region of Tg. It is concluded that the relaxation is due to large-scale segmental motions at the glass transition.
{"title":"α-Relaxation in Nylon studied by TSD","authors":"J. Gil-Zambrano, C. Juhasz","doi":"10.1109/ISE.1985.7341486","DOIUrl":"https://doi.org/10.1109/ISE.1985.7341486","url":null,"abstract":"The TSD technique has been used to study the α-relaxation in Nylon terpolymer films. A well isolated peak observed at about 60 °C in the TSD spectrum suggests the onset of low frequency molecular motions in the polymer. Experimental results indicate that the induced polarization is due to dipole alingment. TSP experiments give a peak characterized by the same position and height as the TSD peak. Tq determined by DTA lies in the region in which the α-peak occurs, a.c. measurements also reveal a loss peak in the region of Tg. It is concluded that the relaxation is due to large-scale segmental motions at the glass transition.","PeriodicalId":6451,"journal":{"name":"1985 5th International Symposium on Electrets (ISE 5)","volume":"1 1","pages":"235-240"},"PeriodicalIF":0.0,"publicationDate":"1985-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86972371","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1985-09-01DOI: 10.1109/ISE.1985.7341565
P. Murphy, K. Hubschi
Electret microphones have played a key role in the miniaturization of hearing aids since 1970. With the passage of time their good stability finally is being confirmed with measured values of only 1.5dB loss in output after 15 years. Today's electrets help to fit hearing aids into the ear canal without sacrifice of performance even though the receiver is placed much closer. New microphones use a diaphragm 1 to 2 micron in thickness to reduce vibration-induced distortion and feed back from the receiver. Teflon back-electrets provide bias and close-coupled preamps impedance matching to the amplifier.
{"title":"Subminiature hearing aid microphones","authors":"P. Murphy, K. Hubschi","doi":"10.1109/ISE.1985.7341565","DOIUrl":"https://doi.org/10.1109/ISE.1985.7341565","url":null,"abstract":"Electret microphones have played a key role in the miniaturization of hearing aids since 1970. With the passage of time their good stability finally is being confirmed with measured values of only 1.5dB loss in output after 15 years. Today's electrets help to fit hearing aids into the ear canal without sacrifice of performance even though the receiver is placed much closer. New microphones use a diaphragm 1 to 2 micron in thickness to reduce vibration-induced distortion and feed back from the receiver. Teflon back-electrets provide bias and close-coupled preamps impedance matching to the amplifier.","PeriodicalId":6451,"journal":{"name":"1985 5th International Symposium on Electrets (ISE 5)","volume":"148 1","pages":"732-737"},"PeriodicalIF":0.0,"publicationDate":"1985-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76023677","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1985-09-01DOI: 10.1109/ISE.1985.7341494
R. A. Moreno, M. T. de Figueiredo
In many cases the profile of an open circuit TSC in Teflon FEP shows two well defined peaks. The first is usually interpreted as due to charge injection from thermally activated surface traps into bulk traps and the second one, occurring at higher temperatures, as charge emission from these volume traps. Extending a calculation done by Kanazawa and Batra [1] a theoretical analysis for the first peak is carried out relating the surface voltage and the total charge in the sample as a function of two parameters: the initial Schubweg and the fraction of charge injected into the sample. The heat pulse technique, giving both, the surface potential and the charge in the sample is suitable to verify experimentally the theory.
{"title":"Injected charge from surface traps into films with deep bulk traps","authors":"R. A. Moreno, M. T. de Figueiredo","doi":"10.1109/ISE.1985.7341494","DOIUrl":"https://doi.org/10.1109/ISE.1985.7341494","url":null,"abstract":"In many cases the profile of an open circuit TSC in Teflon FEP shows two well defined peaks. The first is usually interpreted as due to charge injection from thermally activated surface traps into bulk traps and the second one, occurring at higher temperatures, as charge emission from these volume traps. Extending a calculation done by Kanazawa and Batra [1] a theoretical analysis for the first peak is carried out relating the surface voltage and the total charge in the sample as a function of two parameters: the initial Schubweg and the fraction of charge injected into the sample. The heat pulse technique, giving both, the surface potential and the charge in the sample is suitable to verify experimentally the theory.","PeriodicalId":6451,"journal":{"name":"1985 5th International Symposium on Electrets (ISE 5)","volume":"33 1","pages":"283-287"},"PeriodicalIF":0.0,"publicationDate":"1985-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74302922","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1985-09-01DOI: 10.1109/ISE.1985.7341572
I. Veit
The electroacoustic efficiency of a sound transducer is a very important parameter for the judgement of its practical application. The efficiency achievable by a transmitter consisting of a cylindrical PVDF element has been investigated. On the first results will be reported.
{"title":"The efficiency of electroacoustic transducers with ‘PVDF’ films used to generate sound in the audible frequency range","authors":"I. Veit","doi":"10.1109/ISE.1985.7341572","DOIUrl":"https://doi.org/10.1109/ISE.1985.7341572","url":null,"abstract":"The electroacoustic efficiency of a sound transducer is a very important parameter for the judgement of its practical application. The efficiency achievable by a transmitter consisting of a cylindrical PVDF element has been investigated. On the first results will be reported.","PeriodicalId":6451,"journal":{"name":"1985 5th International Symposium on Electrets (ISE 5)","volume":"22 1","pages":"778-782"},"PeriodicalIF":0.0,"publicationDate":"1985-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81575266","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1985-09-01DOI: 10.1109/ISE.1985.7341492
K. Mazur
Current-voltage characteristic j-V of PMMA at T
PMMA在T
{"title":"Current-voltage characteristic and relation between surface charge density of PMMA thermoelectrets and polarizing voltage","authors":"K. Mazur","doi":"10.1109/ISE.1985.7341492","DOIUrl":"https://doi.org/10.1109/ISE.1985.7341492","url":null,"abstract":"Current-voltage characteristic j-V of PMMA at T<Tg is in sub-ohmic shape (j=gVn where n <1). Using the above data, a two layers condensor (PMMA one-sided metallized and air-gap) has been considered as the formation model of PMMA thermoelectrets. It follows from this model that the inter-facial charge density changes non-linearly with the applied voltage. The analysis data are compared with the experimental results of PMMA thermoelectrets.","PeriodicalId":6451,"journal":{"name":"1985 5th International Symposium on Electrets (ISE 5)","volume":"9 1","pages":"271-276"},"PeriodicalIF":0.0,"publicationDate":"1985-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78607462","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1985-09-01DOI: 10.1109/ISE.1985.7341599
T. Takamatsu, Rui Tian, H. Sasabe
Polypropylene (PP), polyvinylidene fluoride(PVDF) and copoly(vinylidene fluoride/tetrafluoroethylene) (copoly(VDF/TFE)) were polarized with various electric field (E) at room temperature, and the bending piezoelectric coefficients (β331)P of these polymer electrets were measured. The value of β331 for PP electret under the bending deflection of 0.1 cm was estimated as 0.7 cgsesu for the poling field of EP =1×105 V/cm, and increased monotonously with increasing Ep On the other hand, the values of β331 for both PVDF and copoly(VDF/TFE) increased with increasing E, reached a maximum, and then decreased until changing the polarity from negative to positive. Based on these experimental results, a mechanism for the generation of bending piezoelectricity in polymer electrets was proposed.
{"title":"Bending piezo-electricity of polymer electrets","authors":"T. Takamatsu, Rui Tian, H. Sasabe","doi":"10.1109/ISE.1985.7341599","DOIUrl":"https://doi.org/10.1109/ISE.1985.7341599","url":null,"abstract":"Polypropylene (PP), polyvinylidene fluoride(PVDF) and copoly(vinylidene fluoride/tetrafluoroethylene) (copoly(VDF/TFE)) were polarized with various electric field (E) at room temperature, and the bending piezoelectric coefficients (β<inf>331</inf>)<sup>P</sup> of these polymer electrets were measured. The value of β<inf>331</inf> for PP electret under the bending deflection of 0.1 cm was estimated as 0.7 cgsesu for the poling field of E<inf>P</inf> =1×10<sup>5</sup> V/cm, and increased monotonously with increasing E<inf>p</inf> On the other hand, the values of β<inf>331</inf> for both PVDF and copoly(VDF/TFE) increased with increasing E, reached a maximum, and then decreased until changing the polarity from negative to positive. Based on these experimental results, a mechanism for the generation of bending piezoelectricity in polymer electrets was proposed.","PeriodicalId":6451,"journal":{"name":"1985 5th International Symposium on Electrets (ISE 5)","volume":"224 1","pages":"942-946"},"PeriodicalIF":0.0,"publicationDate":"1985-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80033706","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1985-09-01DOI: 10.1109/ISE.1985.7341477
R. Sekar, A. Tripathi, T. C. Goel, P. Pillai
Thermally Stimulated Discharge Current (TSDC) studies have been carried out on PolyMethylmethacrylate (PMMA) and Poly Vinyl Acetate (PVAc) blends. The effect of temperature and field variation on TSDC peaks indicate that the polarization in the blend is due to the charge carrier trapping in the deep traps which leads to the induced dipole formation. No polar peak of individual materials has been observed in the 50:50 as well as 90:10 by weight ratio of PMMA-PVAc blend. It is concluded that in the blend the polymer chains are so entangled that the dipolar contribution in the total polarization becomes almost negligible. The dielectric relaxation parameters are also reported.
{"title":"\"Thermally stimulated discharge current studies on PMMA-PVAc blends\"","authors":"R. Sekar, A. Tripathi, T. C. Goel, P. Pillai","doi":"10.1109/ISE.1985.7341477","DOIUrl":"https://doi.org/10.1109/ISE.1985.7341477","url":null,"abstract":"Thermally Stimulated Discharge Current (TSDC) studies have been carried out on PolyMethylmethacrylate (PMMA) and Poly Vinyl Acetate (PVAc) blends. The effect of temperature and field variation on TSDC peaks indicate that the polarization in the blend is due to the charge carrier trapping in the deep traps which leads to the induced dipole formation. No polar peak of individual materials has been observed in the 50:50 as well as 90:10 by weight ratio of PMMA-PVAc blend. It is concluded that in the blend the polymer chains are so entangled that the dipolar contribution in the total polarization becomes almost negligible. The dielectric relaxation parameters are also reported.","PeriodicalId":6451,"journal":{"name":"1985 5th International Symposium on Electrets (ISE 5)","volume":"48 1","pages":"181-190"},"PeriodicalIF":0.0,"publicationDate":"1985-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87576508","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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