Xu Yang^1,2, Jing Zhang^1,2, Chuanxian Luo^1,2, Qinqing Huang^1,2, Hui Xu^1,2, Guozhi Zhang^1,2,*

Energy Engineering, Vol.120, No.9, pp. 2115-2132, 2023, DOI:10.32604/ee.2023.027198 - 03 August 2023

Abstract In response to the problem of frequent leakage and false alarm of partial discharge insulation defects in GIS, this paper conducts experimental research on intermittent discharge characteristics of common solid insulation defects in GIS. Using true GIS to build a multi-source testing platform for intermittent discharge of solid insulation defects, and using pulse current method, ultra-high frequency method, ultrasonic method, and gas characteristic component detection method to study the variation law of intermittent discharge characteristics of solid insulation defects. The results show that: the intermittent discharge state of metal fouling defects on the solid insulation… More >

Li Xiao^1,2, Xu Yang^1,2,*, Guozhi Zhang^1,2, Lin Cheng^1,2, Yi Jiang^1,2, Chuanxian Luo^1,2, Jing Zhang^1,2

Energy Engineering, Vol.120, No.5, pp. 1239-1252, 2023, DOI:10.32604/ee.2023.025530 - 20 February 2023

Abstract In view of the effective perception demand of PD (Partial Discharge) insulation defect of in-service GIS (Gas Insulated Switchgear), the external UHF (Ultra High Frequency, 0.3−3 GHz) sensing technology for GIS PD insulation defect from resin hole is studied in this paper. Firstly, rectangular waveguide theory is used to analyze the electromagnetic wave propagation characteristics from rectangular resin hole in GIS disc insulator. It is found that the energy of leaked electromagnetic wave mainly concentrates in the frequency band above 1 GHz. Then based on this frequency band characteristics, a cavity-backed bowtie sensor for GIS… More >

Yiwen Zhang¹, Jianjun Xie^1,*, Minghui Sun¹, Shaolong Wang¹, Tengfei Xu^2,3, Yonggen Xu^2,3, Xiaoqing Ding^2,3, Ying Shi¹, Lei Zhang¹

Journal of Renewable Materials, Vol.11, No.5, pp. 2125-2141, 2023, DOI:10.32604/jrm.2023.025127 - 13 February 2023

Abstract Foam glass is a kind of green building material that is widely used because of its excellent thermal insulation and mechanical properties. In this study, the borosilicate foam glass was fabricated by powder sintering method using recycled soda lime waste glass, quartz, and borax as the primary raw materials. CaCO₃ was used as a foaming agent and Na₂CO₃ as a flux agent. Results showed that as the quartz content decreases from 30 to 17.5 wt.% and borax content increases from 5 to 17.5 wt.%, the pore size, porosity, and thermal insulation of borosilicate foam glass increase significantly, while… More > Graphic Abstract

Yue Yu^*

FDMP-Fluid Dynamics & Materials Processing, Vol.19, No.3, pp. 697-709, 2023, DOI:10.32604/fdmp.2022.021482 - 29 September 2022

Abstract The sol-gel method is used to prepare a new nano-alumina aerogel structure and the thermal properties of this nanomaterial are investigated comprehensively using electron microscope scanning, thermal analysis, X-ray and infrared spectrometer analysis methods. It is found that the composite aerogel alumina material has a multi-level porous nano-network structure. When employed for the thermal insulation of high-rise buildings, the alumina nanocomposite aerogel material can lead to effective energy savings in winter. However, it has almost no energy-saving effect on buildings where energy is consumed for cooling in summer. More >

Jianan Wu¹, Ke Xue², Zhaowei Ding³, Lei Lang³, Kang Gu³, Xiaolin Li⁴, Mingli Zhang⁵, Desheng Li^3,6,*

Journal of Renewable Materials, Vol.10, No.12, pp. 3167-3183, 2022, DOI:10.32604/jrm.2022.020265 - 14 July 2022

Abstract Thermal insulation is an important indicator to evaluate the construction material in cold region engineering. As we know, adding the industrial waste as lightweight aggregate or creating the pore inside the cement-based composite could make the texture loose, and the thermal insulating capacity of the material would be improved with this texture. Using these methods, the industrial by-product and engineering waste could be cycled in an efficient way. Moreover, after service the fragmented cement composites paste could be used as aggregate in the thermal insulating concrete again. While the porous texture is not favorable for… More > Graphic Abstract

Ang Wang^1,*, Hui Wang²

FDMP-Fluid Dynamics & Materials Processing, Vol.18, No.5, pp. 1293-1306, 2022, DOI:10.32604/fdmp.2022.018561 - 27 May 2022

Abstract This paper investigates the thermal performance of prefabricated exterior walls using the Computational Fluid Dynamics method to reduce energy consumption. The thermal performance of the prefabricated exterior wall was numerically simulated using the software ANSYS Fluent. The composite wall containing the cavity is taken as the research object in this paper after analysis. The simulation suggests that when the cavity thickness is 20 mm and 30 mm, the heat transfer coefficient of the air-sandwich wall is 1.3 and 1.29, respectively. Therefore, the optimal width of the cavity is 20 mm, and the most suitable material More >

Haizhu Wu^1,#, Jinxing Li^1,#, Shouhu Bao¹, Fuxian Yang¹, Jun Zhang¹, Hisham Essawy^2,*, Guanben Du¹, Xiaojian Zhou^1,*

Journal of Renewable Materials, Vol.10, No.8, pp. 2029-2039, 2022, DOI:10.32604/jrm.2022.019834 - 25 April 2022

Abstract A cellular material in the form of 3-layered sandwich structure material was prepared via sole use of mechanical stirring without any use of a foaming agent, while Tween-80 was employed as a foam stabilizer via a developed in-situ mold casting. The resulting structure displayed a good appearance with no visual defects. The 3-layered composition of the sandwish structure, “nonporous resin layer-porous foam layer-nonporous resin layer”, was examined in terms of the microstructure, density & density distribution, pulverization ratio, mechanical strength, insulation and flame retardant performance. It was indicated from the results that the bonding between the… More > Graphic Abstract

Yanan Chen^1,2,3,4, Ting Yao^1,4,*, Haiping Ren², Zehao Gan¹

CMES-Computer Modeling in Engineering & Sciences, Vol.131, No.3, pp. 1497-1513, 2022, DOI:10.32604/cmes.2022.019589 - 19 April 2022

Abstract The introduction of the electronic medical record (EHR) sharing system has made a great contribution to the management and sharing of healthcare data. Considering referral treatment for patients, the original signature needs to be converted into a re-signature that can be verified by the new organization. Proxy re-signature (PRS) can be applied to this scenario so that authenticity and nonrepudiation can still be insured for data. Unfortunately, the existing PRS schemes cannot realize forward and backward security. Therefore, this paper proposes the first PRS scheme that can provide key-insulated property, which can guarantee both the… More >

Doudou Liu^1,*, Liang Qiao^2,3, Guozhong Li⁴

Journal of Renewable Materials, Vol.10, No.6, pp. 1675-1691, 2022, DOI:10.32604/jrm.2022.018397 - 20 January 2022

Abstract Construction and demolition (C&D) waste has seriously affected the ecological environment. The utilization of C&D waste resources can greatly alleviate this problem, and it is an important way to help achieve the goal of zero carbon in 2050. In this study, insulation concrete blocks were developed with recycled aggregates, cement, fly ash as main raw materials, expanded polystyrene (EPS) insulation boards as block insulation filling material, and self-developed construction waste composite activator, interface enhancer, surface modifier and other additives. Through experimental research and performance test analysis, the best mix ratio of the product and the More >

Wei Chen^1,2, Zhaofeng Guo^3,4,*, Hongda Feng^3,4, Sheng Hu^1,2, Ling Lu^1,2, Chuanmin Chen^3,4, Xiaowen Wu^1,2, Hao Cao^1,2

FDMP-Fluid Dynamics & Materials Processing, Vol.18, No.2, pp. 481-496, 2022, DOI:10.32604/fdmp.2022.015746 - 16 December 2021

Abstract This study investigates a dual-cavity resonant composite sound-absorbing structure based on a micro-perforated plate. Using the COMSOL impedance tube model, the effects of various structural parameters on sound absorption and sound insulation performances are analyzed. Results show that the aperture of the micro-perforated plate has the greatest influence on the sound absorption coefficient; the smaller the aperture, the greater is this coefficient. The thickness of the resonance plate has the most significant influence on the sound insulation and resonance frequency; the greater the thickness, the wider the frequency domain in which sound insulation is obtained. More >