The Experts below are selected from a list of 5205 Experts worldwide ranked by ideXlab platform

Xin Cheng - One of the best experts on this subject based on the ideXlab platform.

  • fabrication and properties of piezoelectric composites designed for process monitoring of Cement Hydration Reaction
    Materials Chemistry and Physics, 2012
    Co-Authors: Dongyu Xu, Shifeng Huang, Xin Cheng
    Abstract:

    Abstract A series of receiving type piezoelectric composites were designed and fabricated by cutting and filling technique. The piezoelectric composites were also optimized from such aspects as matrix phase, functional phase and composite connectivity. The researches show that these piezoelectric composites have larger piezoelectric voltage factor, thickness electromechanical coupling coefficient and lower acoustic impedance than the pure piezoelectric ceramic. The early Cement Hydration Reaction process monitoring result indicates that the ultrasonic wave receiving ability of the piezoelectric composite is obviously better than that of the pure piezoelectric ceramic. Therefore, these kinds of piezoelectric composites have potential application prospect in Cement Hydration Reaction process monitoring.

  • an exploration of 1 3 Cement epoxy resin based piezoelectric composite in Cement Hydration Reaction process monitoring
    Advanced Materials Research, 2011
    Co-Authors: Lei Qin, Shifeng Huang, Xin Cheng
    Abstract:

    1-3 type Cement/epoxy resin based piezoelectric composite was designed and fabricated aiming at providing a new method for Cement Hydration monitoring. Combining with piezoelectric impedance technology, the Cement Hydration Reaction process was monitored by using the composite. The research results show that in the initial Cement Hydration period, the resistance-frequency curves of the sensor drift toward low frequency direction, while the anti-resonance resistance value decreases gradually. With increasing Cement Hydration time, the resistance-frequency curves of the sensor drift toward high frequency direction and the anti-resonance resistance value shows fluctuation changes. The Cement Hydration Reaction process can be divided into different periods according to changes of anti-resonance frequency and anti-resonance resistance value of the sensor.

Lu Lingchao - One of the best experts on this subject based on the ideXlab platform.

  • monitoring of Cement Hydration Reaction process based on ultrasonic technique of piezoelectric composite transducer
    Construction and Building Materials, 2012
    Co-Authors: Xu Dongyu, Huang Shifeng, Lu Lingchao
    Abstract:

    Abstract The piezoelectric composite transducers were fabricated by using different types of piezoelectric composites as core elements, and mixtures of Cement, epoxy resin and hardener as packaging material. The performance testing results show that piezoelectric composite transducers have characteristics of broad band, high sensitivity and good matching ability with Cement material, etc. Based on ultrasonic wave technique, the Hydration Reaction process of Portland Cement was monitored by using the piezoelectric composite transducers as ultrasonic probes. Through analyzing the relationship between waveform and wave parameters of received ultrasonic wave and Cement Hydration Reaction time, the Cement Hydration Reaction rule is obtained. The Cement Hydration Reaction process could be divided into about four periods, that is, induction period, acceleration period, attenuation period and steady period. Especially in initial 24 h of Cement Hydration Reaction, the changes of wave velocity, head wave amplitude and dominant frequency value of received ultrasonic wave are very obvious.

Hashem Akbari - One of the best experts on this subject based on the ideXlab platform.

  • effects of composition and exposure on the solar reflectance of portland Cement concrete
    Cement and Concrete Research, 2002
    Co-Authors: Ronnen Levinson, Hashem Akbari
    Abstract:

    Increasing the solar reflectance (albedo) of a paved surface keeps it cooler in the sun, reducing convection of heat from pavement to air and thereby decreasing the ambient air temperature. Lower air temperatures decrease demand for cooling energy and slow the formation of urban smog. Variations with composition and environmental exposure of the albedos of portland Cement concrete pavements were investigated through laboratory fabrication and exposure of 32 mixes of concrete. Concrete albedo generally correlated with Cement albedo and sand albedo and, after abrasion, with rock albedo. Cement albedo had a disproportionately strong influence on the reflectance of concrete. Simulated weathering, soiling, and abrasion each reduced average concrete albedo, though some samples became slightly more reflective through weathering or soiling. Concrete albedo grew as the Cement Hydration Reaction progressed, but stabilized within six weeks of casting.

  • effects of composition and exposure on the solar reflectance of portland Cement concrete
    Lawrence Berkeley National Laboratory, 2001
    Co-Authors: Ronnen Levinson, Hashem Akbari
    Abstract:

    Increasing the solar reflectance (albedo) of a paved surface keeps it cooler in the sun, reducing convection of heat from pavement to air and thereby decreasing the ambient air temperature. Simulations of the influence of pavement albedo on air temperature in Los Angeles predict that increasing the albedo of 1,250 km2 of pavement by 0.25 would save cooling energy worth $15M yr-1, and reduce smog-related medical and lost-work expenses by $76M yr-1. Most sidewalks and a small fraction of roads and parking areas are paved with portland Cement concrete, which can be made quite reflective through suitable choice of Cement and aggregate. Variations with composition and environmental exposure of the albedos of portland Cement concrete pavements were investigated through laboratory fabrication and exposure of 32 mixes of concrete. Twenty-four mixes yielded substandard, ''rough'' concretes due to high, unmet aggregate water demand. The albedos of the remaining eight ''smooth'' concrete mixes ranged from 0.41 to 0.77 (mean 0.59). Simulated weathering, soiling, and abrasion each reduced average concrete albedo (mean decreases 0.06, 0.05, and 0.19, respectively), though some samples became slightly more reflective through weathering or soiling. Simulated rain (wetting) strongly depressed the albedos of concretes (mean decrease 0.23) until their surfaces were dried. Concrete albedo grew as the Cement Hydration Reaction progressed (mean increase 0.08), but stabilized within six weeks of casting. White-Cement concretes were on average significantly more reflective than gray-Cement concretes. The albedo of the most-reflective white-Cement concrete was 0.18 to 0.39 higher than that of the most-reflective gray-Cement concrete, depending on state of exposure. Concrete albedo generally correlated with Cement albedo and sand albedo, and, after abrasion, with rock albedo. Cement albedo had a disproportionately strong influence on the reflectance of concrete. Efflorescence and surface carbonation whitened some gray-Cement mixes.

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

  • fabrication and properties of piezoelectric composites designed for process monitoring of Cement Hydration Reaction
    Materials Chemistry and Physics, 2012
    Co-Authors: Dongyu Xu, Shifeng Huang, Xin Cheng
    Abstract:

    Abstract A series of receiving type piezoelectric composites were designed and fabricated by cutting and filling technique. The piezoelectric composites were also optimized from such aspects as matrix phase, functional phase and composite connectivity. The researches show that these piezoelectric composites have larger piezoelectric voltage factor, thickness electromechanical coupling coefficient and lower acoustic impedance than the pure piezoelectric ceramic. The early Cement Hydration Reaction process monitoring result indicates that the ultrasonic wave receiving ability of the piezoelectric composite is obviously better than that of the pure piezoelectric ceramic. Therefore, these kinds of piezoelectric composites have potential application prospect in Cement Hydration Reaction process monitoring.

Shifeng Huang - One of the best experts on this subject based on the ideXlab platform.

  • fabrication and properties of piezoelectric composites designed for process monitoring of Cement Hydration Reaction
    Materials Chemistry and Physics, 2012
    Co-Authors: Dongyu Xu, Shifeng Huang, Xin Cheng
    Abstract:

    Abstract A series of receiving type piezoelectric composites were designed and fabricated by cutting and filling technique. The piezoelectric composites were also optimized from such aspects as matrix phase, functional phase and composite connectivity. The researches show that these piezoelectric composites have larger piezoelectric voltage factor, thickness electromechanical coupling coefficient and lower acoustic impedance than the pure piezoelectric ceramic. The early Cement Hydration Reaction process monitoring result indicates that the ultrasonic wave receiving ability of the piezoelectric composite is obviously better than that of the pure piezoelectric ceramic. Therefore, these kinds of piezoelectric composites have potential application prospect in Cement Hydration Reaction process monitoring.

  • an exploration of 1 3 Cement epoxy resin based piezoelectric composite in Cement Hydration Reaction process monitoring
    Advanced Materials Research, 2011
    Co-Authors: Lei Qin, Shifeng Huang, Xin Cheng
    Abstract:

    1-3 type Cement/epoxy resin based piezoelectric composite was designed and fabricated aiming at providing a new method for Cement Hydration monitoring. Combining with piezoelectric impedance technology, the Cement Hydration Reaction process was monitored by using the composite. The research results show that in the initial Cement Hydration period, the resistance-frequency curves of the sensor drift toward low frequency direction, while the anti-resonance resistance value decreases gradually. With increasing Cement Hydration time, the resistance-frequency curves of the sensor drift toward high frequency direction and the anti-resonance resistance value shows fluctuation changes. The Cement Hydration Reaction process can be divided into different periods according to changes of anti-resonance frequency and anti-resonance resistance value of the sensor.