Development of cinnamon essential oil-loaded PBAT/thermoplastic starch active packaging films with different release behavior and antimicrobial activity.

The poly (butylene adipate-co-terephthalate)/thermoplastic starch (PBAT/TPS) active packaging films containing cinnamon essential oil (CEO) were fabricated by melting blending and extrusion casting method. The effects of TPS content (0 %, 10 %, 20 %, 30 %, 40 % and 50 %) on the properties of the films and their application in largemouth bass preservation were studied. As TPS content increased from 0 % to 50 %, the water vapor permeability increased from 7.923 × 10-13 (g•cm/(cm2•s•Pa)) to 23.967 × 10-13 (g•cm/(cm2•s•Pa)), the oxygen permeability decreased from 8.642 × 10-11 (cm3•m/(m2•s•Pa)) to 3.644 × 10-11 (cm3•m/(m2•s•Pa)), the retention of CEO in the films increased. The release rate of CEO from the films into food simulant (10 % ethanol) accelerated with increasing TPS. The films exhibited different antibacterial activity against E. coli, S. aureus, and S. putrefaciens. It was closely related with the release behavior of the CEO. The films containing CEO could efficiently inhibit the decomposition of protein and the growth of microorganisms in largemouth bass. It showed that the higher TPS in the films, the better inhibitory effect. This study provided a new idea for developing PBAT/TPS active films with different release behavior of active agents and different antibacterial activity for food packaging.

Effect of thermal expansion additives on alleviating the ash deposition of high-sodium coal.

The high content of sodium in coal ash can induce severe ash deposit problems on heated surface. Vermiculite has been investigated to solve this problem in drop-tube furnace recently. In this work, the effects of vermiculite and perlite on appearances, inorganic mineral transformation, elemental composition change and Na capture efficiency of ash deposit were investigated. The results show that the molten deposit obtained by drop-tube furnace at 1373 K was transformed into weakly-condensed deposit and strongly-sticky deposit respectively when vermiculite and perlite were added separately. Vermiculite has a better effect on improving the ash deposition than perlite. The mechanism of alleviating the ash deposition by vermiculite and perlite is proposed as follows: (1) The interaction between ash particles is inhibited due to the combination reactions of thermal expansion additive particles with coal ash particles. (2) The coal ash particles attach to the surface and the gap of thermal expansion additive particles, forming a porous structure. (3) With vermiculite added, Mg2SiO4 (forsterite) increases the fusion point of ash deposit. NaCa2Mg4Al(Si6Al2)O22(OH)2 (pargasite) and Mg1.8Fe0.2SiO4 (forsterite ferroan) result in the weak viscosity of ash deposit. (4) With perlite added, silicate and sodium aluminosilicate in perlite react with coal ash to produce a large amount of amorphous substance, which can flow downwards to make the bottom deposit molten and lead to the strong viscosity of total deposit. (5) Vermiculite has a strong capacity for Na capture at 1023 K, and perlite has a strong capacity for Na capture at 1373 K.

Development of New Multilayer Active Packaging Films with Controlled Release Property Based on Polypropylene/Poly(Vinyl Alcohol)/Polypropylene Incorporated with Tea Polyphenols.

The polypropylene/poly(vinyl alcohol)/polypropylene (PP/PVA/PP) multilayer active films with controlled release property were developed, of which the intermediate PVA layer was incorporated with 4% (w/w) tea polyphenols (TP) and the microporous PP films with different pore size were used as the internal controlled release layer. The SEM results showed that each layer of these films was agglutinated tightly. With increasing pore size from 171.05 to 684.03 µm, there were little effect on the films' color and opacity, the tensile strength (TS) and elongation at break (EAB) decreased slightly, the gas barrier (O2 and water vapor) property of the film reduced faintly, the time of achieving the release equilibrium in 50% ethanol decreased from 75 hours to 30 hours. The diffusion coefficient for the films increased with the increase of pore size, from 2.06 × 10-11 cm2 /s to 8.06 × 10-11 cm2 /s, suggesting that the release rate of TP increased as the pore size increased. The results were indicated that its release rate could be controlled by adjusting the size of pore. The films also exhibited different antioxidant activities due to their different release profiles of TP. It showed promise for developing the controlled release active packaging film based on this concept. PRACTICAL APPLICATION: Controlled release packaging is propitious to extension of food shelf life. The microporous polypropylene films with different pore size used as the internal layer of polypropylene/poly(vinyl alcohol)/polypropylene (PP/PVA/PP) multilayer active films was proved that the release rate of tea polyphenols in the intermediate PVA layer released from the films into the food simulant can be controlled by adjusting the size of pore in this study. It showed a good prospect for using microporous or perforation-mediated film as the internal layer of multilayer film to develop the controlled release active packaging film for food packaging.

[Particle Removal Characteristics of an Ultra-low Emission Coal-fired Power Plant].

A 660 MW unit of an ultra-low emission coal-fired power plant in the Beijing-Tianjin-Hebei area was chosen for this study. The particulate matter was sampled with a Dekati low-pressure impactor (DPLI) at the inlet and outlet of flue gas cleaning devices including selective catalytic reduction (SCR), low-low temperature economizer (LLTe), electrostatic precipitator (ESP), wet flue gas desulfurization (WFGD), and wet electrostatic precipitator (WESP). A filter sampling system was also used at the inlet and outlet of the WFGD and WESP. The removal efficiencies of PM1, PM1-2.5, and PM2.5-10 from different flue gas cleaning devices were obtained after ultra-low emission modification. The results show that SCR increases the mass concentration of fine particulates and PM1 by 52.11%. The LLTe improves the removal efficiency of the ESP, especially for particles with a range of 0.1-1 µm. The high-efficiency WFGD removes both SO2 and particulates, but it increases PM1. The mass concentration of PM1 increases by 59.41% and the water-soluble Mg2+, Cl-, and SO42- in PM10 increases. The WESP has a high removal efficiency with respect to PM1, PM1-2.5, and PM2.5-10 and can further reduce the dust concentration. Based on an ultra-low emission reform, the final PM10 emission of this 660 MW unit is 2.04 mg·m-3.

Low NOx combustion and SCR flow field optimization in a low volatile coal fired boiler.

Low NOx burner redesign and deep air staging have been carried out to optimize the poor ignition and reduce the NOx emissions in a low volatile coal fired 330 MWe boiler. Residual swirling flow in the tangentially-fired furnace caused flue gas velocity deviations at furnace exit, leading to flow field unevenness in the SCR (selective catalytic reduction) system and poor denitrification efficiency. Numerical simulations on the velocity field in the SCR system were carried out to determine the optimal flow deflector arrangement to improve flow field uniformity of SCR system. Full-scale experiment was performed to investigate the effect of low NOx combustion and SCR flow field optimization. Compared with the results before the optimization, the NOx emissions at furnace exit decreased from 550 to 650 mg/Nm³ to 330-430 mg/Nm³. The sample standard deviation of the NOx emissions at the outlet section of SCR decreased from 34.8 mg/Nm³ to 7.8 mg/Nm³. The consumption of liquid ammonia reduced from 150 to 200 kg/h to 100-150 kg/h after optimization.

Ionosphere-Constrained Triple-Frequency Cycle Slip Fixing Method for the Rapid Re-Initialization of PPP.

The re-initialization of precise point positioning (PPP) can be avoided by cycle slip detection and correction. Ionospheric delay is critical for cycle slip detection and correction, especially for a long data gap. The frequency diversity from GNSS modernization provides the potential for mitigating the impact of ionospheric delay on cycle slip detection and correction. The proposed method constructs the extra-wide lane (EWL), the wide lane (WL), and the narrow lane (NL) epoch-differenced linear combinations based on the ionosphere constrain criterion, so as to determine the undifferenced cycle slips from the cascading ambiguity resolution. The experiment results show that the cycle slips can be fixed correctly even though cycle slips occur in all the available carrier phase observations, and the 3 min data gaps can be merged without high precision positioning continuity loss. The kinematic experiment shows that the instantaneous re-initialization can be achieved with the proposed method.

Investigation on the fast co-pyrolysis of sewage sludge with biomass and the combustion reactivity of residual char.

Gaining the valuable fuels from sewage sludge is a promising method. In this work, the fast pyrolysis characteristics of sewage sludge (SS), wheat straw (WS) and their mixtures in different proportions were carried out in a drop-tube reactor. The combustion reactivity of the residual char obtained was investigated in a thermogravimetric analyzer (TGA). Results indicate that SS and WS at different pyrolysis temperatures yielded different characteristic gas compositions and product distributions. The co-pyrolysis of SS with WS showed that there existed a synergistic effect in terms of higher gas and bio-oil yields and lower char yield, especially at the WS adding percentage of 80wt%. The addition of WS to SS increased the carbon content in the SS char and improved char porous structures, resulting in an improvement in the combustion reactivity of the SS char. The research results can be used to promote co-utilization of sewage sludge and biomass.

GBAS Ionospheric Anomaly Monitoring Based on a Two-Step Approach.

As one significant component of space environmental weather, the ionosphere has to be monitored using Global Positioning System (GPS) receivers for the Ground-Based Augmentation System (GBAS). This is because an ionospheric anomaly can pose a potential threat for GBAS to support safety-critical services. The traditional code-carrier divergence (CCD) methods, which have been widely used to detect the variants of the ionospheric gradient for GBAS, adopt a linear time-invariant low-pass filter to suppress the effect of high frequency noise on the detection of the ionospheric anomaly. However, there is a counterbalance between response time and estimation accuracy due to the fixed time constants. In order to release the limitation, a two-step approach (TSA) is proposed by integrating the cascaded linear time-invariant low-pass filters with the adaptive Kalman filter to detect the ionospheric gradient anomaly. The performance of the proposed method is tested by using simulated and real-world data, respectively. The simulation results show that the TSA can detect ionospheric gradient anomalies quickly, even when the noise is severer. Compared to the traditional CCD methods, the experiments from real-world GPS data indicate that the average estimation accuracy of the ionospheric gradient improves by more than 31.3%, and the average response time to the ionospheric gradient at a rate of 0.018 m/s improves by more than 59.3%, which demonstrates the ability of TSA to detect a small ionospheric gradient more rapidly.

[An analysis about genetic basis of cotton cultivars in China since 1949 with molecular markers].

The diversity of 166 cotton cultivars(cult.) including 159 upland(G. hirsutum L) and 7 island(G. barbadense L) ones planted mainly in China since 1949 was explored by RAPD, genetic distance(GD) and cluster analysis. The correlation coefficients between Nei's GD of RAPDs and two groups of phenotype data's Euclidean distances (UD) were 0.6445(n = 1770) and 0.7078 (n = 7140), which indicated that RAPD could be used to explore genetic diversity among cotton cultivars in China. The genetic basis of cotton cultivars in China was studied by comparison among different cotton species, different cultivar types, different history periods, different growing regions and different sources. The results showed as follows:within cotton cultivars planted in China, the genetic basis of island cotton cultivars was narrower than that in upland ones; the genetic basis of cultivars released in China since 1949 was narrower than that of introduced ones from outside of China; the genetic basis of hybrids was narrower than that of conventional cultivars(Conv. Cult.); the genetic basis of upland cultivars after 1980 was narrower than that in 1970's; the genetic basis of cultivars in Changjiang cotton region was narrower than that of Huanghuai cotton region, northwestward cotton region was the narrowest. From which some strategies for breeding, especially for the methods of widening the genetic basis of China cotton cultivars, could be understood and withdrawn.