Preparation of Latent Heat Materials Used in Asphalt Pavement and Theirs' Controlling Temperature Performance

Abstract: In order to solve rutting diseases of asphalt concrete pavement, latent heat materials for asphalt pavement were prepared and theirs' controlling temperature performance were studied. Phase change materials (PCM), which were fitted to thermal environment of road were selected, phase change asphalt, diatomite powder and pottery sand granular composite phase change materials (CPCM) were prepared by three kinds of import modes. The CPCM were chosen by comparing the performance of above mentioned materials. Latent heat asphalt mixture (LHAM) was made by replacing mineral powder and fine aggregate with CPCM. Its controlling temperature ability was tested by temperature monitor system. The results show that, comparing to general asphalt mixture, LHAM can reduce temperature to 8-10℃. Therefore, LHAM has a good effect on adjusting road temperature. Introduction The rutting problem of asphalt concrete pavement has bored road transport administrators in the past few years, it is urgent to seek scientific and effective methods to solve the problem. The asphalt mixture is a viscoelastic material, the main factors which affect its mechanical properties are loading and temperature. Loading conditions are not easy to control, so temperature becomes the dominant factor to solve rutting. For a long time, the researchers have focused on improving temperature stability of asphalt and asphalt mixture, asphalt modifing, adding fiber and optimizing gradation and so on measures have been put forward [1-2]. All methods have changed asphalt pavement's temperature passively. Although they have solved some problems in certain domain and condition, temperature-related diseases of asphalt pavement are still very serious. Therefore, the paper was from the angle of improving temperature status of asphalt pavement, latent heat materials used in asphalt pavement were prepared, theirs' temperature performance were tested. The organic phase change materials (OPCM) were imported into inorganic porous materials to prepare composite phase change materials (CPCM). The latent heat asphalt mixture (LHAM) was prepared by mixing CPCM into asphalt mixture through different channels. CPCM is used to absorb heat of pavement constantly. Because of appropriate phase change temperature and high phase change latent heat, its self-thermostat effect performance is great. Preparation of Latent Heat Materials Used in Asphalt Pavement Phase change materials selection The phase change materials (PCM) can change phase with temperature and provide phase change latent heat (PCLH). Phase change materials can be divided into four categories which are solid-solid, solid-liquid, solid-gas and liquid-ga

Gas Path Health Monitoring for a Turbofan Engine Based on a Nonlinear Filtering Approach

Different approaches for gas path performance estimation of dynamic systems are commonly used, the most common being the variants of the Kalman filter. The extended Kalman filter (EKF) method is a popular approach for nonlinear systems which combines the traditional Kalman filtering and linearization techniques to effectively deal with weakly nonlinear and non-Gaussian problems. Its mathematical formulation is based on the assumption that the probability density function (PDF) of the state vector can be approximated to be Gaussian. Recent investigations have focused on the particle filter (PF) based on Monte Carlo sampling algorithms for tackling strong nonlinear and non-Gaussian models. Considering the aircraft engine is a complicated machine, operating under a harsh environment, and polluted by complex noises, the PF might be an available way to monitor gas path health for aircraft engines. Up to this point in time a number of Kalman filtering approaches have been used for aircraft turbofan engine gas path health estimation, but the particle filters have not been used for this purpose and a systematic comparison has not been published. This paper presents gas path health monitoring based on the PF and the constrained extend Kalman particle filter (cEKPF), and then compares the estimation accuracy and computational effort of these filters to the EKF for aircraft engine performance estimation under rapid faults and general deterioration. Finally, the effects of the constraint mechanism and particle number on the cEKPF are discussed. We show in this paper that the cEKPF outperforms the EKF, PF and EKPF, and conclude that the cEKPF is the best choice for turbofan engine health monitoring

Preparation of Latent Heat Materials Used in Asphalt Pavement and Theirs' Controlling Temperature Performance

Abstract: In order to solve rutting diseases of asphalt concrete pavement, latent heat materials for asphalt pavement were prepared and theirs' controlling temperature performance were studied. Phase change materials (PCM), which were fitted to thermal environment of road were selected, phase change asphalt, diatomite powder and pottery sand granular composite phase change materials (CPCM) were prepared by three kinds of import modes. The CPCM were chosen by comparing the performance of above mentioned materials. Latent heat asphalt mixture (LHAM) was made by replacing mineral powder and fine aggregate with CPCM. Its controlling temperature ability was tested by temperature monitor system. The results show that, comparing to general asphalt mixture, LHAM can reduce temperature to 8-10℃. Therefore, LHAM has a good effect on adjusting road temperature. Introduction The rutting problem of asphalt concrete pavement has bored road transport administrators in the past few years, it is urgent to seek scientific and effective methods to solve the problem. The asphalt mixture is a viscoelastic material, the main factors which affect its mechanical properties are loading and temperature. Loading conditions are not easy to control, so temperature becomes the dominant factor to solve rutting. For a long time, the researchers have focused on improving temperature stability of asphalt and asphalt mixture, asphalt modifing, adding fiber and optimizing gradation and so on measures have been put forward [1-2]. All methods have changed asphalt pavement's temperature passively. Although they have solved some problems in certain domain and condition, temperature-related diseases of asphalt pavement are still very serious. Therefore, the paper was from the angle of improving temperature status of asphalt pavement, latent heat materials used in asphalt pavement were prepared, theirs' temperature performance were tested. The organic phase change materials (OPCM) were imported into inorganic porous materials to prepare composite phase change materials (CPCM). The latent heat asphalt mixture (LHAM) was prepared by mixing CPCM into asphalt mixture through different channels. CPCM is used to absorb heat of pavement constantly. Because of appropriate phase change temperature and high phase change latent heat, its self-thermostat effect performance is great. Preparation of Latent Heat Materials Used in Asphalt Pavement Phase change materials selection The phase change materials (PCM) can change phase with temperature and provide phase change latent heat (PCLH). Phase change materials can be divided into four categories which are solid-solid, solid-liquid, solid-gas and liquid-ga

In vitro Effects of Prebiotics and Synbiotics on Apis cerana Gut Microbiota

This study aimed to investigate in vitro effects of the selected prebiotics alone, and in combination with two potential probiotic Lactobacillus strains on the microbial composition of Apis cerana gut microbiota and acid production. Four prebiotics, inulin, fructo-oligosaccharides, xylo-oligosaccharides, and isomalto-oligosaccharides were chosen, and glucose served as the carbon source. Supplementation of this four prebiotics increased numbers of Bifidobacterium and lactic acid bacteria while decreasing the pH value of in vitro fermentation broth inoculated with A. cerana gut microbiota compared to glucose. Then, two potential probiotics derived from A. cerana gut at different dosages, Lactobacillus helveticus KM7 and Limosilactobacillus reuteri LP4 were added with isomalto-oligosaccharides in fermentation broth inoculated with A. cerana gut microbiota, respectively. The most pronounced impact was observed with isomalto-oligosaccharides. Compared to isomalto-oligosaccharides alone, the combination of isomalto-oligosaccharides with both lactobacilli strains induced the growth of Bifidobacterium, LAB, and total bacteria and reduced the proliferation of Enterococcus and fungi. Consistent with these results, the altered metabolic activity was observed as lowered pH in in vitro culture of gut microbiota supplemented with isomalto-oligosaccharides and lactobacilli strains. The symbiotic impact varied with the types and concentration of Lactobacillus strains and fermentation time. The more effective ability was observed with IMO combined with L. helveticus KM7. These results suggested that isomalto-oligosaccharides could be a potential prebiotic and symbiotic with certain lactobacilli strains on A. cerana gut microbiota

Probiotic Gastrointestinal Transit and Colonization After Oral Administration : A Long Journey

Orally administered probiotics encounter various challenges on their journey through the mouth, stomach, intestine and colon. The health benefits of probiotics are diminished mainly due to the substantial reduction of viable probiotic bacteria under the harsh conditions in the gastrointestinal tract and the colonization resistance caused by commensal bacteria. In this review, we illustrate the factors affecting probiotic viability and their mucoadhesive properties through their journey in the gastrointestinal tract, including a discussion on various mucosadhesion-related proteins on the probiotic cell surface which facilitate colonization.Funding Agencies|National Key Research and Development Program of China [2018YFC2000500]; National Natural Science Foundation of ChinaNational Natural Science Foundation of China (NSFC) [32001683]</p