Abstract:To research the effect of freezing temperature on organic matter transformation during freeze／thaw treatment of excess sludge, and to seek the best way of freeze／thaw process, the organic matter transformation during excess sludge disintegration, frozen at -20, -10 and -5 ℃ and thawed at room temperature (20 ℃), respectively, were investigated. The characteristics of organic matter changes of freeze／thaw sludge were also examined using infrared spectrum analysis. The results indicated that the dissolution of solid matter in sludge mainly occurred in the freezing stage, reaching stable after prolonged freezing time. The floc matrix structure was disrupted for the completely frozen sludge (-20 ℃, after 2.5 h; -10 ℃, after 3-4 h and -5 ℃, after 4-6 h), and organic matter sharply released after thawing for 12 h. Under the condition of -5／20 ℃ (freeze／thaw) treatment, the proportion of hydrophilic fraction (HPI) component was increased to 59.3％ and the proteins of hydrophobic components in extracellular biological organic matter (EBOM) were disintegrated thoroughly. In addition, hydrocarbon and carbohydrate absorption peak were increased under -5 ℃ freezing. Compared with the -20／20 ℃ (freeze／thaw) treatment, the intracellular organic matter could be released more thoroughly and the sludge biodegradability was improved via -5／20 ℃ (freeze／thaw) treatment. To obtain the better performance of freeze／thaw treatment, sludge could be firstly frozen at -5 ℃. When sludge was frozen completely (frozen 4-6 h), it could be transferred into the lower freezing temperature for subsequent curing and finally thawed at room temperature.

Abstract:This paper reviews the mechanisms governing high CO₂ acclimation. Acclimation of the photosynthetic apparatus and robustness of pH homeostasis in the cell, rapid shutdown of CO₂-concentrating mechanisms, and adjustment of membranes’ fatty acid composition are currently believed to be the key mechanisms governing microalgae’s tolerance to high CO₂ levels. The potential applications of high CO₂ tolerate microalgae in biological, bio-fuel development and other fields are analyzed. Screening species with high CO₂ tolerance and utilization of physiological and genetic engineering are effective ways to reduce CO₂ emissions and increase microalgae productivity of large-scale cultivation.

Abstract:To discuss the promotion coming from the arbuscular mycorrhizal fungi (AMF) to the wheat and the inhibitory effect of the Fusariumsolani, we selected the excellent local native species—Glomus mosseae, as the materials for the wheat potted experiment, contrasted and analyzed the infection condition, the growth of index, the resistance, and the disease index of the wheat in the case of AMF. The result indicated that the application of the Glomus mosseae would increase the infection rate of the wheat, which could reach 42.2％. The wheat got a strong dependency for Glomus mosseae, and the underground is higher than that in the air; AMF could increase 26.67％, 38.9％ 82.3％,20.33％ for the height, the total area of the root, the aboveground biomass and the underground biomass respectively. AMF could prevent the wheat from Fusariumsolani, visually optimize the stressresistance of the plant, besides, the disease incidence and the disease index decreased 38％ and 3.74 respectively. In the process of wheat, the addition of AMF could effectively promote the growth of the wheat and inhibit the Fusariumsolani.

Abstract:To develop an operating strategy under unconventional conditions for the triple-sleeve energy exchanger (TRESE) based energy storage heat pump system, and to validate stability and reliability at heat exchangers switchover moment for an operating system, a series of unconventional experiments were carried out by using a 2HP prototype. Experimental results indicated that cooling COP of TRESE assisted air source heat pump was 2.8-2.4,7% higher than that of an air source heat pump alone, when ambient temperature was 38-43 ℃. Its heating COP with solar energy assisted could be 2.8 while ambient temperature was -17--10 ℃, 65% higher than that of an air source heat pump alone. On the other hand, switchover of heat exchangers triggered slight fluctuation of operation parameters for operating prototype, while the duration for restoration of stability was less than 420 s, which verified the reliability of the prototype.

Abstract:In order to reveal the mechanisms of spatial and temporal heterogeneity of urban surface thermal environment, the land surface characteristic parameters in different seasons in western Shenzhen including land surface temperature (LST), normalized difference vegetation index (NDVI), normalized difference impervious surface index (NDISI), and normalized difference moisture index (NDMI) were obtained using remote sensing technology. The seasonal variations of land surface thermal environment and its quantitative relationship to biophysical parameters were also analyzed The results showed that significant seasonal variations were observed for the spatial pattern and intensity of thermal environment landscape in the study area. The positive exponential correlation was observed between NDISI and LST, while negative linear correlation between NDMI and LST. These two relations were stable with the seasonal variations. In contrast, the non-linear correlation was observed between NDVI and LST, which varies with the seasonal variations. The multiple linear stepwise regression analysis indicated that the regulating effect on LST decreased in the order: impervious surface area>surface wetness>vegetation cover.

Abstract:A finite element model was established to investigate the stability and bearing capacity of the reticulated dome with steel plates during the construction period of concrete dome using ANSYS. The meshing density was evaluated with the energy error. The nonlinear load-deflection complete process analysis was carried out. Taking the buckling mode at the critical point as initial geometric imperfection form of the dome, the stressed-skin effect on the dome was investigated. The effect of the steel plate thickness, beam section size, rise to span ratio and initial geometric imperfections on the stability of the reticulated dome was discussed. Analysis results show the stressed-skin effect on the dome is significant. The ultimate bearing capacity of structure increases with span ratio in the range of 1／8～1／5, while the maximum increment percentage is 87.3％. The reticulated dome with steel plates is highly sensitive with initial geometric imperfection.

Abstract:To investigate the vibration characteristics of spring vibration isolating foundation for turbine-generator set, the modal tests are performed by model modal test method. A model of 8:1 of spring vibration isolating foundation for turbine-generator set for a 2×1 000 MW in Tianwan nuclear power plant units 3 and 4 is built up according to similarity theory, and then the test of dynamic characteristic is carried out by exciter method, and the natural vibration frequencies, mode shapes and damping ratio are acquired. The results of basic vibrating linear displacement under operation condition are obtained based on the vibration analysis of test data. The results show that the distribution of natural frequencies of structure was sparse in the vicinity of the operating frequency of 25 Hz by designing spring vibration isolating foundation. The maximum linear displacement of test point is 23.19 μm during the start-up and 11.73 μm during the operating speed range. Isolation efficiency of foundation are X-direction to 68.4％, Y-direction to 83.1％, Z-direction to 84.0％, which meet the requirements of Chinese specification "Dynamic machine foundation design specifications".

Abstract:To improve the design reliability of hydronic snow melting system, design alternative of hydronic snow melting systems for pavement in China is discussed. Based on the heat and mass coupled snow melting model, the effect of idling time, heat fluxes, pipe material, meteorological condition and control strategy on the snow melting performance has been investigated. The design alternative for hydronic snow melting system also has been proposed. Results indicated that idling time, input heat flux, thermal properties of pavement materials and embedded pipe play an important role on snow melting performance. Thus, it is possible to adjust the operation parameters and pavement design parameters to optimize the snow melting performance. Meanwhile, location and target performance also affect the required design alternative. According to the weather data corresponding to snow event from 1981 to 2010, the required heating load for hydronic snow melting system in China is suggested. The proposed heating load will give a lot of suggestion in the designation of hydronic heated system for pavement in China.

Abstract:To improve the yield of starch-lipid complexes, the aqueous mixtures of corn starch and stearic acid were heated and homogenized by high pressure to prepare starch-stearic acid complexes. The effects of homogenization pressure, homogenization times and the amount of stearic acid on starch-stearic acid complex formation as well as viscosity, complex index, X-ray diffraction and thermal properties were investigated. The complex index increased and the viscosity decreased with the increasing of the amount of stearic acid, homogenization times and homogenization pressure, and the growth was slowing when the fatty acid content was 3％, homogenization pressure was 100 MPa and homogenization times was 3. X-ray diffraction patterns showed the V-type pattern with the characteristic peaks at 7.4°, 12.9°and 19.8°, and DSC thermogram displayed an endothermic peak at 93-115 ℃. The results indicated the formation of V-helical complexes between starch and stearic acid.

Abstract:A large number of strong ground motion recordings have been collected by the National Strong-Motion Observation Network System of China in the Lushan earthquake sequences after April 0,4. In order to estimate the source parameters of the Lushan aftershocks and the attenuation characteristic of the seismic waves, this study selected 179 acceleration recordings obtained from 15 strong motion stations in 30 aftershocks to estimate the displacement source spectrum and quality factor, based on the generalized inversion technique of the S-wave Fourier amplitude spectrum with one aftershock as the reference event. Various source parameters are estimated by using grid searching technique for each event on the basis of displacement source spectra. It is shown that the average stress drop is slightly lower in Lushan earthquake than that in Wenchuan earthquake. Stress drop is significantly independent on the magnitude, while the apparent stress and the stress drop have favorable positive correlation. The frequency-dependent quality factor Q(f) in this region is found to be 31.867f1.037 5 with the frequency ranging from 0.5 to 20 Hz, the seismic wave attenuates quite faster in Lushan region.

Abstract:Fifteen specimens of the prestressed steel reinforced ultra-high strength concrete beams and three specimens of the prestressed ultra-high strength concrete beams were tested to investigate the flexural ductility of specimens. The test results indicated that: the encased structure steel increased the bearing capacity of specimens, and enhanced the ability of sustaining load after peak load of the specimens. The increase of effective pre-stretching stress, reinforcement ratio of structure steel, reinforcement ratio of ordinary longitudinal bar, and reinforcement ratio of prestressed tendon leaded to the decrease of displacement ductility factor, the decrease of depth of prestressed tendon and structure steel leaded to the decrease of displacement ductility factor. The effect of complex reinforcement index considering of reinforcement on displacement ductility factor were studied. By linear regression of test dates, the simplified calculation formula of displacement ductility factor was obtained, and complex reinforcement index was a single variable in this formula.

Abstract:To better understand the mechanism of concrete frost damage, the influence of NaCl concentration on the absorbed solution amount of reactive powder concrete was investigated. The difference of absorption characteristic between specimen surface and core were correspondingly compared, the absorption characteristics of specimens after 1000 freeze-thaw cycles were studied, and the capillary absorption coefficients of different areas were calculated. Results show that the absorbed solution amount of reactive powder concrete decreases with the increase of NaCl concentration, and it has a linear relation with the t1／2 during 15～180 min and 180～540 min, respectively. The capillary absorption coefficients of specimen surface are much smaller than that of the core. However, the solution absorption of specimens after 1000 freeze-thaw cycles significantly declines, which is only 0.33 times of that before freeze-thaw cycles. The capillary absorption coefficients of specimens after 1000 freeze-thaw cycles are larger in test area which locate farther from the surface of specimen.

Abstract:In order to estimate the influence of particle diameter,nozzle spacing, wind speed and the sprayed ratio on the evaporating efficiency,numerical simulation of direct evaporative cooling of spray in the air ductwas processed using discrete phase model (DPM).Through single factor analysis and multi-factors orthogonal method, the optimal operating conditionswereacquired. Simulation results showed that, the smaller diameter, wind speed and sprayed ratio generates higher evaporating efficiency. Anoptimum nozzle distance should be determined by saturated water-gas ratio, wind speed,injection velocity and injection angle. According to simulation results, considering the economyof the spray system, particlediameterunder 30 μm, wind speed under 1 m／s, sprayed ratio higher than 0.7, the evaporating efficiency could achieve 92％, with saturated efficiency higher than 65％.

Abstract:The content of EPS affects the characteristics of sludge and formation of the granular sludge.To study the effect of substrate concentration and type on the EPS content and the sludge settling performance, six SBR reactors with different ammonia concentrations and different substrates were used. The results showed that the EPS content increased with the increase of ammonia concentration only when ammonia nitrogen concentration was 60-200 mg／L, but did not increase significantly when the ammonia nitrogen concentration exceeded 200 mg／L. The relationship between the ratio of polysaccharide to protein and ammonia concentration was a linear correlation, with R² of 0.972 3. The EPS was influenced by the substrate type, higher content of polysaccharide with glucose as organic, and higher content of protein with domestic waste water as substrate. The protein and polysaccharide were biodegradable, which could be used by microorganisms as carbon source and energy when the substrate was deficient. The sludge sedimentation could be affected by the EPS content, and the SVI decreased with the increase of EPS content.

Abstract:There is an underlying assumption that run-off and rainfall in a given urban catchment are equivalent and, further, to use design rainfall depth as a proxy for run-off in hydrological analyses and calculations. However, when employing this approach, it is difficult to accurately and fully reflect the variability in rainfall characteristics. To address this issue, a method for the copula-based multivariate frequency analysis of rainfall characteristics was proposed by using historical rainfall data (1961-2012) from Guangzhou city. First, continuous rainfall time series were divided into individual rainfall events using the rainfall intensity method. Then the characteristic variables of rainfall were calculated by sampling using the annual maximum method. Finally, a three-dimensional copula was introduced to build a multivariate joint probability distribution model of rainfall characteristics. The results show that the copula-based multivariate analysis is easy to implement and provides reliable results. This approach can be used to analyse the conditional probabilities of variables for different orders of magnitude. It can fully reflect rainfall characteristics, which serve an important reference for urban flood control and drainage planning.

Abstract:Considering the space power conditioning unit (PCU) needs high reliable design,especially for it works in harsh environment, a robust design and optimal method is proposed. Firstly,the mathematical model of sequential switching shunt regulator(S3R) is shown to be suitable for regulated bus power systems. Secondly, optimize the bus capacitor parameter by the parameter sweep analysis. Thirdly, when all the components change simultaneously in the worst case, the performance of the S3R circuit meets the design requirements and the shunt component meets the derating requirements in the Monte Carlo analysis and stress analysis. Finally, simulate two failure modes: the load changes in pulse mode and the current supply of the second-stage solar array is zero,the simulation results show that the output of the bus voltage is stable and ripples in the specified range.

Abstract:To solve the problem of asynchronism of sensors′ outputs in integrated navigation systems a novel INS/GNSS/CNS integrated federated filtering algorithm based on dynamic vector formed information distribution is proposed. Based on the operating character of the subsystems, an INS/GNSS position integrated model and an INS/CNS velocity integrated model are analysed and designed as the federated filtering model. And the filtering accuracy is improved by using the dynamic vector formed information distribution algorithm. To solve the problem of asynchronism in measurement, an asynchronous incoordinate interval algorithm is proposed, and the filtering period is divided into time update period and measurement update period．Simulation results indicate that this algorithm can effectively implement the asynchronism fusion of the information from INS, GNSS and CNS. Comparing with the general asynchronism federated filter, the proposed algorithm has significant improvement in estimation accuracy and important application value.

Abstract:In this paper, accelerated freeze-thaw tests and repeated loading tests on C40 and C50 concrete specimens were introduced to study the effects of freeze-thaw cycles on the mechanical performance of concrete under dynamic load. The test results showed that the mechanical performance of freeze-thaw damaged concrete under repeated loading decreased significantly and the characteristic curves of dynamic constitutive relation changed distinctly after freeze and thaw, the enveloping line and reloading curves before stress peak exhibited a concave shape due to the compaction effects, the strain hysteresis of unloading curve became more serious and the unloading curves tended to coincide gradually as the freeze-thaw cycles increased. The relationships between freeze-thaw cycles, strength grades of concrete and the characteristic value of stress-strain curve including mechanical properties parameters and constitutive model parameters were also studied to establish a dynamic constitutive relation for concrete with freeze-thaw damage.

Abstract:To optimize the production process of oat tea, we take the soluble solid content and sensory evaluation as the index, time and temperature of stir-frying and extraction ratio as factors to conduct the Box-Behnken designed response surface test. The optimum oat tea with the best taste and stable nature can be achieved with the stir-frying temperature of 175.41 ℃, stir-frying time of 9.39 min, and extraction ratio 1∶10. 73.

Abstract:To improve the situation of dust concentration exceeds in crushing chamber and obtain rational parameters for the design of dust removal by ventilation, due to the similarity theory and the motion equations of gas-solid two-phase flow, the similarity index was educed and a similarity model device was designed for the specific situation in the crushing chamber. Furthermore, the dust concentration distribution of similarity model in crushing chamber was simulated by using software named Fluent. After the comparison with similar experimental data analysis, the result showed that the simulation result was consistent with the experimental data. Therefore, the results indicated that dust concentration in chamber under trap wall condition is lower than it under the reflect condition. When the wind velocity at entrance was in the range of 0.2 m/s to 0.5 m/s, dust concentration gradually reduced with the increasement of wind velocity. Finally, after the installation of downdraught dedusting system, the dust concentration was below 2 mg/m³, and the average removal rate reached 90%.

Abstract:To determine the form of crossing facilities,The traffic characteristics of pedestrians’ walking speed and vehicles’ queuing spacing, headway of steering were analyzed in signalized intersection. The probabilistic model of acceptable gap choice for pedestrians crossing the intersection was constructed by survey and analysis of conflicting operations between pedestrians and vehicles. On the theoretical foundation of characteristics from alternate operations between pedestrians and vehicles, rules concerning pedestrians walking forward, avoidance, lateral walking forward, vehicles stop-to-slow following, steering following, and target lanes selection in bidirectional six lanes were established; selective rules concerning conflicts identification between pedestrians and vehicles at pedestrian crossroads were introduced. Therefore, the cellular automata model of alternate operations between pedestrians and vehicles at signal intersection was constructed through overlapping the previous two rules. Taking the main signal intersection in the bidirectional six lanes as an example, the applicability of exclusive pedestrian signal phase and overpassing facilities were analyzed. The result indicates that the overpassing facilities are supposed to be adopted when the traffic less than 90 s, the proportion of left turn green split time is no less than 50％ and the pedestrian volume is no less than 2 700 Ped·(h·m)-1.