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Hanbing Xu - One of the best experts on this subject based on the ideXlab platform.

  • Effects of ultrasonic vibration on Degassing of aluminum alloys
    Materials Science and Engineering A-structural Materials Properties Microstructure and Processing, 2008
    Co-Authors: Hanbing Xu, Thomas T. Meek
    Abstract:

    In order to investigate the effects of ultrasonic vibration on Degassing of aluminum alloys, three experimental systems have been designed and built: one for ultrasonic Degassing in open air, one for ultrasonic Degassing under reduced pressure, and one for ultrasonic Degassing with a purging gas. Experiments were first carried out in air to test Degassing using ultrasonic vibration alone. The limitations with ultrasonic Degassing were outlined. Further experiments were then performed under reduced pressures and in combination with purging argon gas. Experimental results suggest that ultrasonic vibration alone is efficient for Degassing a small volume of melt. Ultrasonic vibration can be used for assisting vacuum Degassing, making vacuum Degassing much faster than that without using ultrasonic vibration. Ultrasonically assisted argon Degassing is the fastest method for Degassing among the three methods tested in this research. More importantly, dross formation during ultrasonically assisted argon Degassing is much less than that during argon Degassing. The mechanisms of ultrasonic Degassing are discussed.

  • effects of ultrasonic field and vacuum on Degassing of molten aluminum alloy
    Materials Letters, 2007
    Co-Authors: Hanbing Xu, Thomas T. Meek
    Abstract:

    Ultrasonic Degassing, an environmentally clean and cheap technique, is an efficient way of Degassing in a static volume melt. Vacuum Degassing has also been tested as a beneficial and clean method in producing high quality products. An experimental device which combines the vacuum Degassing and ultrasonic Degassing has been built. Parametric studies have been carried out to investigate the efficacy of the ultrasonic Degassing of molten aluminum alloy under reduced pressure. The results indicate that a combination of these two techniques makes Degassing more efficient.

  • Degassing OF ALUMINUM A356 ALLOY USING ULTRASONIC VIBRATIONS
    2007
    Co-Authors: Hanbing Xu, Thomas T. Meek
    Abstract:

    In order to investigate the effects of ultrasonic vibration on Degassing of aluminum alloys, three experimental systems have been designed and built: one for ultrasonic Degassing in open air, one for ultrasonic Degassing under reduced pressure, and one for ultrasonic Degassing with a purging gas. Experiments were first carried out in air to test Degassing using ultrasonic vibration alone. The limitations with ultrasonic Degassing were outlined. Further experiments were then performed under reduced pressures and in combination with purging argon gas. Experimental results suggest that ultrasonic vibration alone is efficient for Degassing a small volume of melt. Ultrasonic vibration can be used for assisting vacuum Degassing, making vacuum Degassing much faster than that without using ultrasonic vibration. Ultrasonically assisted argon Degassing is the fastest method for Degassing among the three methods tested in this research. More importantly, dross formation during ultrasonically assisted argon Degassing is much less than that during argon Degassing. The mechanisms of ultrasonic Degassing are discussed.

  • Degassing of Aluminum Alloys Using Ultrasonic Vibration
    2006
    Co-Authors: Thomas T. Meek, Hanbing Xu
    Abstract:

    The research was intended to lead to a better fundamental understanding of the effect of ultrasonic energy on the Degassing of liquid metals and to develop practical approaches for the ultrasonic Degassing of alloys. The goals of the project described here were to evaluate core principles, establish a quantitative basis for the ultrasonic Degassing of aluminum alloy melts, and demonstrate the application of ultrsaonic processing during ingot casting and foundry shape casting.

  • Degassing of molten aluminum A356 alloy using ultrasonic vibration
    Materials Letters, 2004
    Co-Authors: Hanbing Xu, Xiaogang Jian, Thomas T. Meek
    Abstract:

    This article addresses ultrasonic Degassing in aluminum A356 alloy. An experimental setup has been built for the Degassing of aluminum using ultrasonic vibration at a frequency of 20 kHz and vibration intensities up to 1500 W. Ultrasonic Degassing has been tested in different volumes of aluminum melt for various processing temperatures and durations. The efficiency of Degassing is evaluated by a density measurement for reduced pressure samples. Experimental results indicate that a steady-state hydrogen concentration can be obtained within a few minutes of ultrasonic vibration, regardless of the initial hydrogen concentration in the melt. The dynamics of hydrogen evolution as a function of processing time, melt temperature, and initial hydrogen concentration have been investigated. The mechanism of ultrasonic Degassing is discussed. It is suggested that ultrasonic vibration can be used to reduce porosity formation in aluminum alloys.

Thomas T. Meek - One of the best experts on this subject based on the ideXlab platform.

  • Effects of ultrasonic vibration on Degassing of aluminum alloys
    Materials Science and Engineering A-structural Materials Properties Microstructure and Processing, 2008
    Co-Authors: Hanbing Xu, Thomas T. Meek
    Abstract:

    In order to investigate the effects of ultrasonic vibration on Degassing of aluminum alloys, three experimental systems have been designed and built: one for ultrasonic Degassing in open air, one for ultrasonic Degassing under reduced pressure, and one for ultrasonic Degassing with a purging gas. Experiments were first carried out in air to test Degassing using ultrasonic vibration alone. The limitations with ultrasonic Degassing were outlined. Further experiments were then performed under reduced pressures and in combination with purging argon gas. Experimental results suggest that ultrasonic vibration alone is efficient for Degassing a small volume of melt. Ultrasonic vibration can be used for assisting vacuum Degassing, making vacuum Degassing much faster than that without using ultrasonic vibration. Ultrasonically assisted argon Degassing is the fastest method for Degassing among the three methods tested in this research. More importantly, dross formation during ultrasonically assisted argon Degassing is much less than that during argon Degassing. The mechanisms of ultrasonic Degassing are discussed.

  • effects of ultrasonic field and vacuum on Degassing of molten aluminum alloy
    Materials Letters, 2007
    Co-Authors: Hanbing Xu, Thomas T. Meek
    Abstract:

    Ultrasonic Degassing, an environmentally clean and cheap technique, is an efficient way of Degassing in a static volume melt. Vacuum Degassing has also been tested as a beneficial and clean method in producing high quality products. An experimental device which combines the vacuum Degassing and ultrasonic Degassing has been built. Parametric studies have been carried out to investigate the efficacy of the ultrasonic Degassing of molten aluminum alloy under reduced pressure. The results indicate that a combination of these two techniques makes Degassing more efficient.

  • Degassing OF ALUMINUM A356 ALLOY USING ULTRASONIC VIBRATIONS
    2007
    Co-Authors: Hanbing Xu, Thomas T. Meek
    Abstract:

    In order to investigate the effects of ultrasonic vibration on Degassing of aluminum alloys, three experimental systems have been designed and built: one for ultrasonic Degassing in open air, one for ultrasonic Degassing under reduced pressure, and one for ultrasonic Degassing with a purging gas. Experiments were first carried out in air to test Degassing using ultrasonic vibration alone. The limitations with ultrasonic Degassing were outlined. Further experiments were then performed under reduced pressures and in combination with purging argon gas. Experimental results suggest that ultrasonic vibration alone is efficient for Degassing a small volume of melt. Ultrasonic vibration can be used for assisting vacuum Degassing, making vacuum Degassing much faster than that without using ultrasonic vibration. Ultrasonically assisted argon Degassing is the fastest method for Degassing among the three methods tested in this research. More importantly, dross formation during ultrasonically assisted argon Degassing is much less than that during argon Degassing. The mechanisms of ultrasonic Degassing are discussed.

  • Degassing of Aluminum Alloys Using Ultrasonic Vibration
    2006
    Co-Authors: Thomas T. Meek, Hanbing Xu
    Abstract:

    The research was intended to lead to a better fundamental understanding of the effect of ultrasonic energy on the Degassing of liquid metals and to develop practical approaches for the ultrasonic Degassing of alloys. The goals of the project described here were to evaluate core principles, establish a quantitative basis for the ultrasonic Degassing of aluminum alloy melts, and demonstrate the application of ultrsaonic processing during ingot casting and foundry shape casting.

  • Degassing of molten aluminum A356 alloy using ultrasonic vibration
    Materials Letters, 2004
    Co-Authors: Hanbing Xu, Xiaogang Jian, Thomas T. Meek
    Abstract:

    This article addresses ultrasonic Degassing in aluminum A356 alloy. An experimental setup has been built for the Degassing of aluminum using ultrasonic vibration at a frequency of 20 kHz and vibration intensities up to 1500 W. Ultrasonic Degassing has been tested in different volumes of aluminum melt for various processing temperatures and durations. The efficiency of Degassing is evaluated by a density measurement for reduced pressure samples. Experimental results indicate that a steady-state hydrogen concentration can be obtained within a few minutes of ultrasonic vibration, regardless of the initial hydrogen concentration in the melt. The dynamics of hydrogen evolution as a function of processing time, melt temperature, and initial hydrogen concentration have been investigated. The mechanism of ultrasonic Degassing is discussed. It is suggested that ultrasonic vibration can be used to reduce porosity formation in aluminum alloys.

Jitai Niu - One of the best experts on this subject based on the ideXlab platform.

  • Research on water simulation experiment of the rotating impeller Degassing process
    Materials Science and Engineering A-structural Materials Properties Microstructure and Processing, 2009
    Co-Authors: Xiangyu Liu, Jitai Niu
    Abstract:

    Abstract The purification technology by rotating impeller Degassing (RID) is becoming one of the important methods to purify molten Al alloys. The Degassing efficiency of the RID process is determined by the interaction of many factors. The relationship between technological parameters and Degassing efficiency can be defined by building the proper mathematical model which can be used for guidance in practical production. In this work, a quadratic polynomial model of Degassing efficiency was built by using the orthogonal regression method. The response equation of Degassing rate to the gas flow rate, rotational speed and blowing time was fitted by using multiple-regression estimation methods. Furthermore, the optimal processing parameters of the RID process were defined, namely rotational speed v = 374 rpm / min and gas flow rate q = 1.8 dm3/min and the optimized parameters were confirmed by smelting trial.

  • Analyses of the Influencing Factors of Rotating Impeller Degassing Process and Water Simulation Experiment
    Materials Science Forum, 2008
    Co-Authors: Xiangyu Liu, Hong Wei Wang, Kuang Fei Wang, Jitai Niu
    Abstract:

    On the basis of similarity principle a water-simulative study of the process of rotating impeller Degassing (RID) was executed by means of self-made purifying system. The influencing factors on the RID process were studied and laid a theoretical basis for the further development of this kind of technique. The shape of vortex originated in rotating of impeller and its adverse effect on Degassing effectiveness were discussed. Meanwhile the influences of shape as well as position of bluff body on Degassing efficiency were investigated. The impacts of parameters such as gas feed rate and rotational speed of on Degassing efficiency were discussed. The result revealed that the structure and design parameters of impeller are the decisive factors of effectiveness of RID facilities, and the design of the swivel head ought to aim for increasing the additional turbulent shear stress on air bubble and improving the Degassing condition.

Xiangyu Liu - One of the best experts on this subject based on the ideXlab platform.

  • Research on water simulation experiment of the rotating impeller Degassing process
    Materials Science and Engineering A-structural Materials Properties Microstructure and Processing, 2009
    Co-Authors: Xiangyu Liu, Jitai Niu
    Abstract:

    Abstract The purification technology by rotating impeller Degassing (RID) is becoming one of the important methods to purify molten Al alloys. The Degassing efficiency of the RID process is determined by the interaction of many factors. The relationship between technological parameters and Degassing efficiency can be defined by building the proper mathematical model which can be used for guidance in practical production. In this work, a quadratic polynomial model of Degassing efficiency was built by using the orthogonal regression method. The response equation of Degassing rate to the gas flow rate, rotational speed and blowing time was fitted by using multiple-regression estimation methods. Furthermore, the optimal processing parameters of the RID process were defined, namely rotational speed v = 374 rpm / min and gas flow rate q = 1.8 dm3/min and the optimized parameters were confirmed by smelting trial.

  • Analyses of the Influencing Factors of Rotating Impeller Degassing Process and Water Simulation Experiment
    Materials Science Forum, 2008
    Co-Authors: Xiangyu Liu, Hong Wei Wang, Kuang Fei Wang, Jitai Niu
    Abstract:

    On the basis of similarity principle a water-simulative study of the process of rotating impeller Degassing (RID) was executed by means of self-made purifying system. The influencing factors on the RID process were studied and laid a theoretical basis for the further development of this kind of technique. The shape of vortex originated in rotating of impeller and its adverse effect on Degassing effectiveness were discussed. Meanwhile the influences of shape as well as position of bluff body on Degassing efficiency were investigated. The impacts of parameters such as gas feed rate and rotational speed of on Degassing efficiency were discussed. The result revealed that the structure and design parameters of impeller are the decisive factors of effectiveness of RID facilities, and the design of the swivel head ought to aim for increasing the additional turbulent shear stress on air bubble and improving the Degassing condition.

Thilo Hofmann - One of the best experts on this subject based on the ideXlab platform.

  • biochar total surface area and total pore volume determined by n2 and co2 physisorption are strongly influenced by Degassing temperature
    Science of The Total Environment, 2017
    Co-Authors: Gabriel Sigmund, Thorsten Huffer, Thilo Hofmann
    Abstract:

    The surface area and pore volume of carbonaceous materials, which are commonly determined by N2 and/or CO2 gas-physisorption, are important parameters when describing environmental processes such as adsorption. Their measurement requires prior Degassing of samples, which can change the nature of the material. Current guidelines for biochar characterization recommend different Degassing temperatures. To investigate how Degassing temperatures affect gas-physisorption we systematically degassed a range of materials (four biochars, carbon nanotubes, and Al2O3 reference material) at different temperatures (105, 150, 200, 250 and 300°C; for ≥14h each). Degassing temperatures had no effect on Al2O3 or carbon nanotubes but the measured surface areas and pore volumes of biochars increased by up to 300% with Degassing temperature. An equation is presented for predicting surface area obtained at different Degassing temperatures. Elemental analysis and results from sorption batch experiments suggest that surface area and pore volume may increase as biochar components volatilize during Degassing. Our results showed that Degassing temperatures change material properties and influence gas-physisorption measurements, and therefore need to be standardized. These results may also apply to the characterization of other complex materials, including carbon nanotubes coated with natural organic matter and fouled activated carbon.