Benjamin Lepers^a,*, Aditya Putranto^b,c, Martin Umminger^d, Guido Link^a, John Jelonnek^a

Frontiers in Heat and Mass Transfer, Vol.5, pp. 1-11, 2014, DOI:10.5098/hmt.5.13

Abstract The use of high power microwaves to perform explosive spalling of surface concrete is a promising technique with applications in the area of concrete facilities decommissioning. The mechanism that creates explosive spalling is an interactive process of the thermal stress from high temperature gradients and the pore pressure generated from the water vaporization. In order to better predict the total stress distribution, the temperature has to be calculated by including the effect of water vaporization and water transport through a porous medium. In this paper, a one dimensional model solving the heat and diffusion equation for liquid and vapor phase… More >

Benjamin Lepers^a,∗, Thomas Seitz^a, Guido Link^a, John Jelonnek^a,b, Mark Zink^c

Frontiers in Heat and Mass Transfer, Vol.6, pp. 1-6, 2015, DOI:10.5098/hmt.6.20

Abstract A compact 10 kW microwave applicator operating at 2.45 GHz for fast volumetric heating and thermal cracking of lignite briquettes has been successfully designed and tested. In this paper, the applicator design and construction are presented together with a sequentially coupled electromagnetic, thermal-fluid and mechanical Comsol model. In a first step, this model allows us to calculate the power density inside the lignite material and the temperature distribution in the applicator for different water flow rates. In a second step, the total stress due to the thermal dilatation, the internal pressure inside the ceramic and the contact pressure from the… More >

Benan Shu^1,*, Lixian Guo¹, Bing Qiu¹, Tengyu Yang¹, Tao Sun¹, Wenjun Qiu¹, Min Zhou¹, Putao Song², Yuanyuan Li³, Diego Maria Barbieri⁴, Shaopeng Wu^5,*

Journal of Renewable Materials, Vol.9, No.10, pp. 1781-1794, 2021, DOI:10.32604/jrm.2021.015659

Abstract As an innovative maintenance technology of asphalt pavement, encapsulated rejuvenator used to improve its self-healing performance has been widely investigated by researchers in recent years. In this work, the selfhealing properties of asphalt mixture with and without encapsulations were comparatively studied considering these parameters: Healing time, healing cycles and microwave heating. Three-point bending strength recovery test and fatigue loading cycles recovery test were conducted for two kinds of encapsulations containing the healing agents present inside the asphalt mixture, namely compartmented Ca-alginate/SiO2 fiber and compartmented Ca-alginate/graphene oxide fiber. The results showed that the optimum healing time was three days. After the… More >

Sulardjaka Sulardjaka^1,*, Sri Nugroho¹, Norman Iskandar¹, Agus P. Adi¹, Deni F. Fitriyana²

FDMP-Fluid Dynamics & Materials Processing, Vol.17, No.2, pp. 385-395, 2021, DOI:10.32604/fdmp.2021.011784

Abstract Zeolite A has been successfully synthesized from geothermal waste with natrium aluminate and natrium silicate using conventional (C-H) and microwave heating (M-H) for the hydrothermal treatment. The products obtained for different aging times have been characterized using X-Ray Diffraction (XRD), Fourier transformation infrared spectroscopy (FTIR), and scanning electron microscopy (SEM). It is shown that with the M-H process, zeolite can be formed at relatively low temperature (100°C) in a relatively short time (40 min). The crystallization of zeolite A has been found to be generally promoted by an increase of aging and synthesis time; however, it has also been observed… More >