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Number of results: 61
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Abstract

The purpose of this paper is to present and analyse the decision-making problem faced by a future house owner - selection of the optimal solution of building thermal insulation in relation to the selected criteria, both related to costs and future benefits. The problem of selecting the best solutions in the construction sector is widely discussed in the science literature. In this paper, the authors decided to solve the raised problem by using the Entropy method.

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Authors and Affiliations

P. Nowak
M. Skłodkowski
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Abstract

In the authors’ opinion, the issue of incorrectly functioning water insulation of foundation walls in the existing buildings in Poland is currently rather common. The paper includes a multicriteria analysis aimed at arranging the selected options of the foundation wall vertical water insulation technology in an existing model historic building using the weighted sum, entropy and AHP methods. Each of the studied solutions was evaluated in terms of the following criteria: costs of construction works, time of execution of construction works, popularity of using particular insulation options by other contractors, durability of the executed insulation and the degree of nuisance of the executed works

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Authors and Affiliations

J. Rosłon
M. Seroka
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Abstract

Before disassemble and demolition of five granulation towers the authors planned and carried out measurements of the intensity of vibrations induced during the fall of the dismantled components of towers on the ground. The main aim of the study was to determine the maximum permissible weight of falling elements of the towers during the demolition, in terms of ensuring the protection of buildings and equipment located in the vicinity of the works. It was unacceptable to increase the vibration amplitude displacement in each section of measurement on each of the three perpendicular axes by more than 2 μm peak-to-peak value and the absolute velocity of RMS of vibration amplitude couldn’t be increased by more than 1 mm/sec value than the background vibration during the demolition of the towers. Preliminary experimental studies were conducted on a test stand and the measurements were made on the real object. The amplitudes of vibration waves displacement and velocity were recorded on the measurement section in the direction of the protected building. The results of measurements were used to identify the propagation of the shock wave and the effectiveness of the proposed insulation layers.

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Authors and Affiliations

Jan Targosz
Jarosław Bednarz
Wojciech Lisowski
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Abstract

Additional sound sources are used as actuators in the vast majority of active noise reduction systems. One of the possible opportunities to extend the field of applications of active noise reduction systems is using active structures of variable sound insulation. The paper presents an analysis of ways of reducing noise with a structure of variable sound insulation consisting of a metal plate, active elements (Macro Fiber Composite), and a control system. The paper presents results of acoustic radiation simulations and measurements of sound intensity generated by the structure under the influence of stimulation by an acoustic wave. Simulations of mechanical vibrations and acoustic radiation for the plate were performed with the finite element method and ANSYS software. Simulation results made it possible to select locations for gluing the active elements and sensors. Analyses of the sound pressure level in the space to which the plate is radiating made it possible to determine dominant frequencies in the characteristics and, as a result, indicate vibration modes that can be reduced. Sound intensity measurements were performed with a three-way probe of USP mini Microflown. Results of simulations and measurements show that it is possible to achieve an improvement of the insulating power of a metal plate by approx. 10 dB.

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Authors and Affiliations

Paweł Górski
Michał Kozupa
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Abstract

A verification study of ultrasound transmission numerical simulation results with experiment results is presented in this paper. The work considers a model of a transformer tank which is filled with electro insulating oil. In the experiment, performed under laboratory conditions, an ultrasound wave is generated by a piezoelectric transducer that is fixed in the centre of the tank and measured by another transducer mounted inside the tank at three distances: 10, 20 and 30 cm from the sound source. The transducer is able to measure and generate acoustic waves in the ultrasound frequency band up to 1 MHz. The simulation considers numerical calculation of acoustic pressure distribution inside the tank in which acoustic source emits waves with frequency equal to 100 kHz. Verification analysis has confirmed consistency of the numerically calculated values with the measurement results.

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Authors and Affiliations

Andrzej Cichoń
Daria Wotzka
Tomasz Boczar
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Abstract

The article presents the results of diagnostic measurements of partial discharge signal propagation from the winding insulation in electrical machinery, which were performed using an on-line method. This paper describes the results of experiments and the acquired experience in the monitoring of winding insulation in high power and high voltage electrical machines which are important in industrial production processes. The authors show the measurement techniques employed in their research. Representative measurement results are presented along with their analysis. The authors use an SKF monitoring systems to measure: vibrations, temperature, and humidity, as major factors affecting partial discharge activity in the from winding insulation of electrical machines.

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Authors and Affiliations

Zbigniew Plutecki
Sławomir Szymaniec
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Abstract

The wet flashover voltage of medium voltage insulators made of a silicone rubber is 8% lower than the wet flashover voltage of a porcelain insulator with an identical profile. These surprising results, obtained in 2012, were confirmed again in 2019. The flashover development on the composite insulator is very short (less than 30 ms). On the other hand, on the porcelain insulator, the flashover develops longer (1–3 seconds). The Koppelmann equation was modified, and the Obenaus model to calculate the flashover voltage of insulators under the artificial rain was presented. Attention was paid to the importance of insulator diameters and the phenomenon of water cascades.
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Bibliography

[1] Kuhlman K., Hochspannungsisolatoren, Elektrotechnische Zeitschrift (in German), vol. 31, iss. 3, pp. 51–55 (1910).
[2] Lustgarten J., High-tension porcelain line insulators, Journal of the Institution of Electrical Engineers, vol. 49, pp. 235–279 (1912).
[3] IEC 60060-1:2010, High-voltage test techniques – Part 1: General definitions and test requirements, edition 3 (2010).
[4] Gallet G., How to design a rain apparatus for the dielectric tests, IEEE PES Summer Meeting, San Francisco, paper A 75 490-3 (1975).
[5] Huc J., Rowe S.W., Wet testing installation design, 5th Int. Symposium on High Voltage Engineering, Athens, paper 52.03 (1983).
[6] Chrzan K.L., Streubel H., Artificial rain test of outdoor long rod insulators, Int. Symposium on High Voltage Engineering, ISH, Cap Town, paper E-31 (2009).
[7] Rizk F.A.M., Kamel S.I., Modelling of HVDC wall bushing flashover in nonuniform rain, IEEE Trans. on Power Delivery, vol. 6, no. 4, pp. 1650–1662 (1991).
[8] Matsuoka M., Naito K., Irie T., Kondo K., Evaluation methods of polymer insulators under contaminated conditions, IEEE Transmission and Distribution Asia Pacific Conference, pp. 2197–2202 (2002).
[9] Chrzan K.L., Swierzyna Z., Artificial rain test of insulators, Przegl˛ad Elektrotechniczny (in Polish), no. 11b, pp. 218–221 (2012).
[10] Szpor S., Dzierzek H.,WiniarskiW., High voltage engineering, WNT (in Polish),Warsaw, vol. 1, p. 88 (1978).
[11] Estorff W., Cron H., High Voltage insulator as pollution problem, ETZ (in German), vol. 73, iss. 3, pp. 57–62 (1952).
[12] Chrzan K.L., Leakage currents on naturally contaminated porcelain and silicone insulators, IEEE Trans. on Power Delivery, vol. 25, no. 2, pp. 904–910 (2010), DOI: 10.1109/TPWRD.2009.2034665.
[13] Streubel H., Calculation of AC Flashover voltage under rain, Hermsdorfer Technische Mitteilungen (in German), iss. 31, pp. 974–980 (1971).
[14] Lan L., Gorur R.S., Computation of ac wet flashover voltage of ceramic and composite insulators, IEEE Transactions on Dielectrics and Electrical Insulation, vol. 15, no. 5, pp. 1346–1352 (2008), DOI: 10.1109/TDEI.2008.4656243.
[15] Erler F., About AC pollution flashover on thick insulators, Elektrie (in German), iss. 3, pp. 100–102 (1969).
[16] Hao Y., Liao Y., Kuang Z., Sun Y., Shang G., Zhang W., Mao G., Yang L., Zhang F., Li L., Experimental investigation on influence of shed parameters on surface rainwater characteristics of largediameter composite post insulators under rain conditions, Energies, vol. 13, no. 19, 5011 (2020), DOI: 10.3390/en13195011.
[17] Ely C.H.A., Lambeth P.J., Looms J.S.T., The booster shed: prevention of flashover of polluted substation insulators in heavy wetting, IEEE Transactions on Power Apparatus and Systems, vol. PAS-97, no. 6, pp. 2187–2197 (1978).
[18] Yang L., Kuang Z., Sun Y., Liao Y., Hao Y., Li L., Zhang F., Study on Surface Rainwater and Arc Characteristics of High-Voltage Bushing with Booster Sheds under Heavy Rainfall, IEEE Access, vol. 6, pp. 146865–146875 (2020), DOI: 10.1109/ACCESS.2020.3012978.
[19] Okada N., Ikeda K., Kondo K., Ito S., Contamination withstand voltage characteristics of hydrophobic polymers insulators under simulated rain conditions, IEEE Int. Symposium on Electrical Insulation, Boston, USA, pp. 228–231 (2002).
[20] Gorur R.S., de la O A., El-Kishky A., Chowdhary M., Mukherjee H., Sundaram R., Burnham J.T., Sudden flashovers of nonceramic insulators in artificial contamination tests, IEEE Transactions on Dielectrics and Electrical Insulation, vol. 3, no. 1, pp. 79–86 (1997), DOI: 10.1109/94.590870.
[21] Hartings R., The AC-Behavior of a Hydrophilic and Hydrophobic Post Insulator during Rain, IEEE Trans. on Power Delivery, vol. 9, no. 3, pp. 1584–1592 (1994).
[22] Wang S., Liang X., Huang L., Experimental study on the pollution flashover mechanism of polymer insulators, IEEE Power Engineering Society Winter Meeting, Singapore, pp. 2830–2833 (2000), DOI: 10.1109/PESW.2000.847332.
[23] de la O A., Gorur R.S., Flashover of contaminated nonceramic outdoor insulators in a wet atmosphere, IEEE Transactions on Dielectrics and Electrical Insulation, vol. 5, no. 6, pp. 814–823 (1998), DOI: 10.1109/94.740762.
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Authors and Affiliations

Krystian Leonard Chrzan
1
Henryk Marek Brzeziński
2

  1. Wroclaw University of Technology, Poland
  2. Łukasiewicz Research Network – Institute of Electrical Engineering, Poland
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Abstract

A commercially available ASPEN PLUS simulation using a pipe model was employed to determine the maximum safe pipeline distances to subsequent booster stations as a function of carbon dioxide (CO2) inlet pressure, ambient temperature and ground level heat flux parameters under three conditions: isothermal, adiabatic and with account of heat transfer. In the paper, the CO2working area was assumed to be either in the liquid or in the supercritical state and results for these two states were compared. The following power station data were used: a 900 MW pulverized coal-fired power plant with 90% of CO2recovered (156.43 kg/s) and the monothanolamine absorption method for separating CO2from flue gases. The results show that a subcooled liquid transport maximizes energy efficiency and minimizes the cost of CO2transport over long distances under isothermal, adiabatic and heat transfer conditions. After CO2is compressed and boosted to above 9 MPa, its temperature is usually higher than ambient temperature. The thermal insulation layer slows down the CO2temperature decrease process, increasing the pressure drop in the pipeline. Therefore in Poland, considering the atmospheric conditions, the thermal insulation layer should not be laid on the external surface of the pipeline.

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Authors and Affiliations

Andrzej Witkowski
Mirosław Majkut
Sebastian Rulik
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Abstract

The results from the experimental research are presented in the abstract. The experimental research involved utilization of the sludge from the mine water treatment plant of Coal Quarry ČSA/Czechoslovak Army/ (hereinafter “ČSA”) and Coal Quarry Jana Švermy (hereinafter “JŠ”) in the segment of thermal insulation mortars. The mine water treatment is described below including chemical and mineralogical sludge composition as the additional component of the binding material in the polyurethane thermal insulation mortars. Furthermore the composition of experimental mixtures of the thermal insulation polyurethane mortar is presented in the work and its physical-mechanical properties. The monitored elements included the strength characteristics, heat conductivity coefficient λ, and water vapour diffusion coefficient μ.

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Authors and Affiliations

V. Václavík
J. Daxner
J. Valíček
V. Dombek
T. Dvorský
M. Kušnerová
B. Václavíková
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Abstract

An alternative method for analysis of acoustic emission (AE) signals generated by partial discharges (PD), based on a correlation between voltage phase run and AE pulses, so called phase resolved PD pattern (PRPD), is presented in the paper. PRPD pattern is a well-known analysis tool commonly used in such PD diagnostic methods as conventional electrical and UHF ones. Moreover, it yields various signal analysis abilities and allows a direct correlation indication between measurement results achieved using different methods. An original PRPD measurement methodology applied for AE method as well as some exemplary measurement results and further data analysis capabilities are presented in the paper. Also a comparative analysis of PRPD patterns achieved using various measurement methods and different PD source configurations have been investigated. All presented experiments were done under laboratory conditions using PD model sources immersed in the insulation oil. The main purpose of the presented research is to indicate an all-embracing analytical tool that yields an ability to direct comparison (qualitative as well as quantitative) of the AE measurement results with other commonly applied PD measurement methods. The presented results give a solid fundamental for further research work concerning a direct correlation method for AE and other described in the paper diagnostic techniques, mainly in order to continue PD phenomena analysis and assessment in real life high voltage apparatus insulation systems under normal onsite operation conditions.
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Authors and Affiliations

Michał Kunicki
Andrzej Cichoń
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Abstract

The article presents the results concerning the use of clustering methods to identify signals of acoustic emission (AE) generated by partial discharge (PD) in oil-paper insulation. The conducted testing featured qualitative analysis of the following clustering methods: single linkage, complete linkage, average linkage, centroid linkage and Ward linkage. The purpose of the analysis was to search the tested series of AE signal measurements, deriving from three various PD forms, for elements of grouping (clusters), which are most similar to one another and maximally different than in other groups in terms of a specific feature or adopted criteria. Then, the conducted clustering was used as a basis for attempting to assess the effectiveness of identification of particular PD forms that modelled exemplary defects of the power transformer’s oil-paper insulation system. The relevant analyses and simulations were conducted using the Matlab estimation environment and the clustering procedures available in it. The conducted tests featured analyses of the results of the series of measurements of acoustic emissions generated by the basic PD forms, which were obtained in laboratory conditions using spark gap systems that modelled the defects of the power transformer’s oil-paper insulation.
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Authors and Affiliations

Sebastian Borucki
Jacek Łuczak
Dariusz Zmarzły
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Abstract

Partial discharges (PD) are influencing electrical insulating systems of high voltage electrical devices. Typically, in laboratory and diagnostics AC tests focused on measuring and analysis of PD, a pure sinusoidal voltage waveform is assumed. However, in practice the spectral content of the working voltage is rarely so ideal and additional spectral components have a significant impact on the discharge behaviour in electrical insulation systems. In this paper the influence of voltage harmonics on PD behaviour and phase-resolved PD patterns evolution is analysed. The presented experiments were conducted on a specimen representing a gaseous inclusion embedded in electrical insulation. The experimental results showed that various harmonic compositions superimposed on the fundamental sinusoidal waveform have a significant impact on PD intensity and maximum charge. In consequence, the derived patterns of PD phase, and magnitude distributions are distorted, and statistical parameters calculated on their basis are changed. In certain en- vironments, neglecting harmonic content in the testing voltage may lead to a misleading interpretation and assessment of PD severity.
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Authors and Affiliations

Marek Florkowski
Barbara Florkowska
Paweł Zydroń
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Abstract

In this study, agar-based nanocomposite films containing ultra-porous silica aerogel particles were fabricated by gel casting using an aqueous agar/silica aerogel slurry. The silica aerogel particles did not show significant agglomeration and were homogeneously distributed in the agar matrix. Transmission electron microscopy observations demonstrated that the silica aerogel particles had a mesoporous microstructure and their pores were not incorporated into the agar polymer molecules. The thermal conductivities of the agar and agar/5 wt.% silica aerogel nanocomposite films were 0.36 and 0.20 W·m–1·K–1, respectively. The transmittance of the agar films did not decrease upon the addition of silica aerogel particles into them. This can be attributed to the anti-reflection effect of silica aerogel particles.

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Authors and Affiliations

Min-Jin Lee
Hyun-Ah Jung
Kyong-Jin Lee
Haejin Hwang
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Abstract

The main problem in the measurement of airborne sound insulation is the measurement of the sound power radiated by the barrier, in practice performed by measuring the sound pressure level and the acoustic absorption in the receiving room. Large variations of the sound pressure level in a reverberation room indicate the presence of dominating strong standing waves, so that it becomes necessary to install diffusing elements. In ISO 10140, the limits have been defined in which the reverberation time at frequencies at and above 100 Hz should be included. Sometimes, however, in the case of rooms with a large volume, obtaining the required parameters is difficult and sometimes even impossible. It should then be checked whether the measured sound insulation depends on the reverberation time.

The paper presents the results of sound insulation measurements at various reverberation time lengths in subsequent stages of diffusing elements installation in the receiving room. An analysis of diffusing materials amount and arrangement influence on the uniformity of the sound pressure level distribution and reverberation time in the room as well as the value of the measured sound insulation was carried out. Uncertainty of sound insulation measurement with partial uncertainties was adopted as a criterion supporting the assessment of the obtained results.

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Authors and Affiliations

Dominik Mleczko
Tadeusz Wszołek
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Abstract

The article presents the application of Acoustic Emission (AE) method for detection and registration of partial discharges (PD) generated in medium voltage (MV) cable isolation and MV cable head. The insulation of the high voltage cable is made of a flexible material whose properties are characterised by a high coefficient of attenuation of the acoustic signals. For this reason, the AE method has not been used so far to detect PD in energetic cables. The subjects of the research were the MV cable and the standard T-type cable head. The cable contained defects which were the source of partial discharges. In case of cable head the PD were provoked by thin grounded electrode which was introduced into connector opening. The results of AE measurements are presented in the form of spectrograms. Acoustic Emission was evoked when the applied voltage level reached the value of 7.5 kV for the cable and 4 kV for the cable head. The authors used the acoustic instrumentation of their own design intended for future field use. Obtaining successful results of partial discharges measurements using the acoustic method in the cable insulation makes an original contribution of the presented work.
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Authors and Affiliations

Zbigniew Ranachowski
1
ORCID: ORCID
Krzysztof Wieczorek
2
Przemysław Ranachowski
1
Tomasz Dębowski
1

  1. Institute of Fundamental Technological Research, Polish Academy of Sciences, Warsaw, Poland
  2. Department of Electrical Engineering Fundamentals, Wrocław University of Science and Technology, Wrocław, Poland
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Abstract

Extensive efforts have been made for many years by the power generating industry to replace conventional solid and liquid insulation with synthetic materials. Those measures are aimed at increasing the load capacity, improved fire safety and extending transformer life during exploitation. Modern insulating materials include aramid fibre-based paper and insulating fluids made of synthetic and natural esters. The paper presents research results of the electrostatic charging tendency (ECT) of mixtures of fresh and aged mineral oil Trafo En with synthetic ester Midel 7131 and natural ester Midel 1204. The measurements were taken in a flow-through system using the pipes made of metal, cellulose and aramid paper. The influence of the liquid flow velocity, the type of material of the measuring pipe and the mixture content on the level of the streaming electrification current generation was determined.

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Authors and Affiliations

Maciej Zdanowski
Marcin Maleska
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Abstract

Varying ohmic loss in the winding of electrical machines, which are operated at various operating points, results in temperature changes during operation. Particularly, when the temperature is varying dynamically, the insulation system suffers from repeated thermalmechanical stress, since the thermal expansion coefficients of the insulating materials and copper conductors are different. For the appropriate design of an insulation system, the effect of thermal-mechanical stress must be known. In the present work, motorettes are subjected to repeated thermal cycles. The expected lifetime is estimated and compared to the lifetime which is achieved by applying a lifetime-model which only considers thermal aging while ignoring thermal-mechanical stress effects. In addition, the hotspot temperature is simulated, the lifetime at the hotspot is estimated as theworst case. As expected, the results indicate that the thermal-mechanical stress plays a significant role during dynamic thermal aging of the winding insulation system. To better understand the thermal-mechanical stress effect, the resulting thermal-mechanical stress in a single wire is analyzed by the finite element method. A preliminary analysis of the aging mechanism of materials due to cyclic thermal-mechanical stress is performed with the theory of material fatigue.
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Bibliography

[1] Stone G.C., Boulter E.A., Culbert I., Dhirani H., Electrical insulation for rotating machines: design, evaluation, aging, testing, and repair, John Wiley & Sons (2004).
[2] Rothe R., Hameyer K., Life expectancy calculation for electric vehicle traction motors regarding dynamic temperature and driving cycles, 2011 IEEE International Electric Machines and Drives Conference (IEMDC), Niagara Falls, ON, Canada, pp. 1306–1309 (2011).
[3] Huang Z., Modeling and testing of insulation degradation due to dynamic thermal loading of electrical machines, Licentiate Thesis, Lund University, Lund (2017).
[4] Chen W., Nelson C., Thermal stress in bonded joints, IBM Journal of Research and Development, vol. 23, no. 2, pp. 179–188 (1979).
[5] Arrhenius S., On the heat of dissociation and the influence of temperature on the degree of dissociation of the electrolytes, Zeitschrift für Physikalische Chemie (in German, Über die Dissociationswärme und den Einfluss der Temperatur auf den Dissociationsgrad der Elektrolyte), vol. 4, no. 1, pp. 96–116 (1889).
[6] Dakin T.W., Electrical insulation deterioration treated as a chemical rate phenomenon, Transactions of the American Institute of Electrical Engineers, vol. 67, no. 1, pp. 113–122 (1948).
[7] Ruf A., Pauli F., Schröder M., Hameyer K., Lifetime modelling of non-partial discharge resistant insulation systems of electrical machines in dynamic load collectives, e & i Elektrotechnik und Informationstechnik (in German, Lebensdauermodellierung von nicht-teilentladungsresistenten isoliersystemen elektrischer maschinen in dynamischen lastkollektiven), vol. 135, no. 2, pp. 131–144 (2018).
[8] Pauli F., Schröder M., Hameyer K., Design and evaluation methodology for insulation systems of low voltage drives with preformed coils, 2019 9th International Electric Drives Production Conference (EDPC), Esslingen, Germany, pp. 1–7 (2019).
[9] Madonna V., Giangrande P., Lusuardi L., Cavallini A., Gerada C., Galea M., Thermal overload and insulation aging of short duty cycle, aerospace motors, IEEE Transactions on Industrial Electronics, vol. 67, no. 4, pp. 2618–2629 (2019).
[10] Sciascera C., Galea M., Giangrande P., Gerada C., Lifetime consumption and degradation analysis of the winding insulation of electrical machines, 2016 8th IET International Conference on Power Electronics, Machines and Drives (PEMD), Glasgow, UK, pp. 1–5 (2016).
[11] IEC 60505, Evaluation and qualification of electrical insulation systems (2011).
[12] Ruf A., Paustenbach J., Franck D., Hameyer K., A methodology to identify electrical ageing of winding insulation systems, 2017 IEEE International Electric Machines and Drives Conference (IEMDC), Miami, FL, USA, pp. 1–7 (2017).
[13] Pauli F., Ruf A., Hameyer K., Low voltage winding insulation systems under the influence of high du/dt slew rate inverter voltage, Archives of Electrical Engineering, vol. 69, no. 1, pp. 187–202 (2020).
[14] IEC 60034–18–41, Rotating electrical machines – Part 18–41: Partial discharge free electrical insulation system (Type I) used in rotating electrical machines fed from voltage converters – Qualification and quality control tests (2014).
[15] Nikolova G., Ivanova J., Interfacial shear and peeling stresses in a two-plate structure subjected to monotonically increasing thermal loading, Journal of Theoretical and Applied Mechanics, vol. 51 (2013).
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Authors and Affiliations

Liguo Yang
1
ORCID: ORCID
Florian Pauli
1
Kay Hameyer
1
ORCID: ORCID

  1. Institute of Electrical Machines (IEM), RWTH Aachen University, Schinkelstraße 4, 52062 Aachen, Germany
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Abstract

The density, compressive strength, and thermal insulation properties of fly ash geopolymer paste are reported. Novel insulation material of glass bubble was used as a replacement of fly ash binder to significantly enhance the mechanical and thermal properties compared to the geopolymer paste. The results showed that the density and compressive strength of 50% glass bubble was 1.45 g/cm3 and 42.5 MPa, respectively, meeting the standard requirement for structural concrete. Meanwhile, the compatibility of 50% glass bubbles tested showed that the thermal conductivity (0.898 W/mK), specific heat (2.141 MJ/m3K), and thermal diffusivity (0.572 mm2/s) in meeting the same requirement. The improvement of thermal insulation properties revealed the potential use of glass bubbles as an insulation material in construction material.
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Authors and Affiliations

Noor Fifinatasha Shahedan
1
ORCID: ORCID
Mohd Mustafa Al Bakri Abdullah
1 2
ORCID: ORCID
Norsuria Mahmed
1 2
ORCID: ORCID
Liew Yun Ming
1 2
ORCID: ORCID
Shayfull Zamree Abd Rahim
1
ORCID: ORCID
Ikmal Hakem A Aziz
1
ORCID: ORCID
Aeslina Abdul Kadir
3
ORCID: ORCID
Andrei Victor Sandu
4
ORCID: ORCID
Mohd Fathullah Ghazali
1
ORCID: ORCID

  1. Universiti Malaysia Perlis (UniMAP), Center of Excellence Geopolyme & Green Technology (CEGeoGTech), Perlis, Malaysia
  2. Universiti Malaysia Perlis (UniMAP), Faculty of Chemical Engineering Technology, Perlis, Malaysia
  3. Universiti Tun Hussein Onn Malaysia, Faculty of Civil and Environmental Engineering, Johor, Malaysia
  4. Faculty of Materials Science and Engineering, Gheorghe Asachi Technical University of Iasi, Iasi, Romania
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Abstract

The exothermic insulating riser played an important role in the solidification process of metal liquid for the improvement of casting quality. This paper focused on the use of organosilicon slag to replace part of the aluminum powder as an exothermic agent for the riser, to reduce production costs and turn waste into treasure. The experiments firstly studied the effect of organosilicon slag content on the combustion temperature and holding time and determined the components of the riser exothermic agent and organosilicon slag. On this basis, the effects of the content of Na3AlF6 flux and alkali phenolic resin binder on the combustion heating time and strength properties of the riser were studied. And the ratio of mixed oxidants was determined by single-factor orthogonal experiments to optimize the addition of three oxidants, Fe3O4, MnO2, and KNO3. Finally, the performance of the riser prepared after optimization was compared with that of the riser prepared with general aluminum powder. The results showed that with the mixture of 21% organosilicon slag and 14% aluminum powder as the exothermic agent, the highest combustion temperature of the prepared exothermic insulating riser was 1451℃ and the holding time was 193 s; the optimal content of Na3AlF6 flux was 4%, and the best addition alkali phenolic resin binder was 12%; the optimized mixing ratio of three oxidants was 12% for Fe3O4, 6% for MnO2, and 6% for KNO3. Under the optimized ratio, the maximum combustion temperature of the homemade riser was 52℃ and the heat preservation time was 14% longer compared with the conventional exothermic insulating riser with 25-35% aluminum powder.
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Authors and Affiliations

Jijun Lu
1
ORCID: ORCID
Jiangbing Qian
1
ORCID: ORCID
Lei Yang
1
ORCID: ORCID
Huafang Wang
1
ORCID: ORCID

  1. School of Mechanical Engineering and Automation, Wuhan Textile University, China
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Abstract

This paper describes preparation methodology and research results of newly developed materials from post-production fibrous waste that are resistant to high temperatures. Widely available raw materials were used for this purpose. Such approach has significant impact on the technological feasibility and preparation costs. Obtained materials were verified via applying of various tests including characterization of shrinkage, porosity, density and water absorption as well as X-ray analysis (XRD), followed by mechanical bending and compressive strength determination.

Based on the research results, the possible applications of materials as thermal insulators were indicated.

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Authors and Affiliations

K. Kogut
K. Kasprzyk
R. Kłoś
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Abstract

Balconies are elements of some multi-storey buildings. Thermo-insulated fasteners are components that connect balcony slabs with the building structure. Their main task is the transfer of loads in connections of balcony slabs with the building while also minimizing thermal bridges. The article presents analytical calculations performed to develop the new type of thermal insulated fasteners and to determine their load-bearing capacity. The aim of this article is to demonstrate that analytical calculations based on commonly utilized principles of reinforced concrete and steel structure operation along enable the development of the effective design algorithm of insulated fasteners and allow for a quick analysis of various geometric variants of these fasteners. The article presents the adaptation of typical algorithms for calculation of steel and reinforced concrete structures for the analysis of non-typical load-bearing capacity states that occur during the calculation of insulated fasteners. The load-bearing capacities of individual fasteners are shown in M-V interaction diagrams (bending moment – shearing force).
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Authors and Affiliations

Tomasz Janiak
1
ORCID: ORCID

  1. Bydgoszcz University of Science and Technology, Faculty of Civil and Environmental Engineering and Architecture, Al. prof. S. Kaliskiego 7, 85-796 Bydgoszcz, Poland
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Abstract

Suspension line insulators are during their operation subject to static forces and variable loads, usually of a cyclic character. These variable loads have a significant impact on the mechanical durability of composite insulators. A method of providing durability forecast for composite line insulators based on fatigue characteristics has been proposed. The method allows providing durability forecast of insulators in a wide range of variable loadings, i.e. from quasi-static to high amplitude loadings.
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Authors and Affiliations

Jerzy Bielecki
1
ORCID: ORCID
Jacek Wańkowicz
1
ORCID: ORCID

  1. Institute of Power Engineering – Research Institute, 8 Mory Str., 01-330 Warsaw, Poland
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Abstract

The modern cabin of heavy duty machines have to fulfil a number of requirements which deal with operators' work comfort. More and more often, the vibroacoustic and thermal comforts decide about the cabin quality. This paper presents principles of acoustic and thermal calculations as well as their use in combined assessment.

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Authors and Affiliations

Zygmunt Dziechciowski
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Abstract

Urethane foam mattresses are commonly used as cushioning when placing panel flooring on the floor slab of a building. Urethane foam consists of elastic fibres with pores. Both elements can affect the performance of the insulation against impact sounds. However, these effects have not yet been detailed, and they may change if the material properties or constitution of the fibres and pores in the cushioning change. In this paper, we propose an analytical model for use in evaluating the performance of insulation against floor impact sound. This model was used to examine the contribution of the pores versus the elastic fibres to wave transmissions from the flooring surface to the slab. The results reveal that the constitution of the foam (either open or closed cells of pores) and the thickness and hardness of the cushion layer strongly affect the sound insulation performance of the floor.
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Authors and Affiliations

RuiLin Mu
Masahiro Toyoda
Daiji Takahashi

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