Traffic state recognition using static images and FCM

Accurate recognition of the traffic condition can proactively alert drivers who will enter the congested road to avoid congestion, so that the degree of congestion will not be increased. And it is also the basis to make scientific decision on active traffic managements, and conducive to alleviate congestion, improve the traffic efficiency, save energy and reduce emission. In this paper, the traffic surveillance videos are sampled every three minutes to build static image database, and the road area is marked as the region of interest (ROI), and then ROI images are normalized in terms of angle and scale. The three image features in ROI, i.e., average gradient, corner and long edge number, are then extracted. Finally, the fuzzy C-means clustering (FCM) method is used to classify the traffic condition into two classifications, i.e., flowing traffic and congestion. Experimental results show that the proposed algorithm can effectively identify the traffic condition involved in the image by the accuracy of 98％. Moreover, compared with the video-based approaches, this method greatly reduces the implementation cost.     

Synergistic effects of high pressure processing and slightly acidic electrolysed water on the inactivation of Bacillus cereus spores

Bacillus spores are concerns for their resistance to heat, high pressure processing (HPP), and disinfectants. We examined the effects of HPP and slightly acidic electrolysed water (SAEW) on inactivation of B. cereus spores. Spores' suspensions were prepared with 2‐(N‐morpholino) ethanesulfonic acid (MES) buffer or SAEW with available chlorine content (ACC) of 24, 35, 44 or 55 mg L^?1, and then subjected to HPP. The individual effects of HPP or SAEW on spores were negligible (<1.0 log CFU mL^?1). With factorial design and anova analysis, HPP + SAEW treatment was shown to have significantly positive effects on spores’ inactivation. The optimal conditions were 300 MPa HPP + SAEW with 44 mg L^?1 ACC or 200 MPa HPP + SAEW with 44 mg L^?1 ACC + 500 MPa HPP, producing reductions of 3.27 and 3.99 log CFU mL^?1, respectively. HPP + SAEW have potentials to serve as two effective hurdle techniques for inactivating B. cereus spores.     

Fabrication and properties of degradable poly(amino acid)/nano hydroxyapatite bioactive composite

Poly(amino acid)/nano hydroxyapatite (PAA/n-HA) bioactive composite was prepared by in situ melting polymerization. The composition, structure and morphology as well as glass transition temperature (T_g), dynamic mechanical properties of the PAA/n-HA composite were characterized by infrared spectrometer, X-ray diffractometer, X-ray photoelectron spectroscopy, scanning electron microscope, differential scanning calorimeter, and dynamic mechanical analyzer. The results indicated that the n-HA particles were uniformly distributed into PAA matrix and some interactions were found at the interface between PAA and n-HA, and the crystallinity of PAA in the composite decreased with the increase of n-HA content. The T_g and storage modulus of the composite increased with increasing n-HA content, demonstrating that the n-HA content had obvious effects on the crystallization kinetic parameters and thermo properties of the PAA/n-HA composite. In addition, the n-HA amount had evident effects on the degradation of the PAA/n-HA composite in phosphate buffered saline (PBS), and the weight loss ratio of the composite decreased with the increase with n-HA content. The pH value of the medium was stable around 7.40 after the composite immersion into PBS for 8 weeks. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Perforative silica microsphere-modified phenolphthalein-based poly(arylene ether sulfone) composites: tensile and thermal properties

Perforative silica microspheres (PSMs) were prepared by an emulsion method coupled with sol–gel technology and phase separation. Next, phenolphthalein-based poly(arylene ether sulfone)/PSM composites (PES-C/PSM) were fabricated. PSM was characterized by scanning electron microscopy (SEM) and the Brunauer–Emmett–Teller (BET) method. The as-synthesized PSM exhibited a spherical shape with an external diameter of 2–10 µm, surface area of 166.5 m²/g and pore volume of 1.35 cm³/g. SEM and energy-dispersive spectroscopy (energy-dispersive spectroscopy) were used to characterize the morphology and the composition of the composite, respectively. Both SEM and energy-dispersive spectroscopy results revealed that the PES-C polymer chains penetrated into the PSM pores. In addition, the effect of PSM weight content on the mechanical properties and thermal stability of the composites was characterized by tensile tests and thermal analysis, respectively. A 19% increase in tensile strength and a 29% increase in breaking elongation of PES-C were achieved by the addition of 0.50 wt% PSM. Moreover, the thermal oxidative stability of PES-C was remarkably improved with the incorporation of PSM. Compared with pristine PES-C, the final degradation temperature was enhanced by 42 °C at 1.0 wt% PSM loading. Our studies have indicated that PSM is a kind of promising reinforcement for improvement of tensile and thermal properties of engineering plastics.     

Thermal management and catalytic combustion stability characteristics of premixed methane/air in heat recirculation meso‐combustors

In order to illuminate heat recirculation effect on catalytic combustion stability and further improve energy conversion efficiency in meso‐combustor, the catalytic combustion characteristics of the combustor with/without preheating channels are numerically studied at steady conditions. It is found that methane conversion rate and combustion efficiency increases by 2% to 3% and approximately 9% in the heat recirculation meso‐combustor, indicating that heat recirculation effect facilitates more complete combustion of methane and medium components. Preheating channels show positive effects on improving combustion stability in the heat recirculation meso‐combustor. On one hand, preheating channels facilitate heat recirculation effect, and heat recirculation rate exceeds 10% for all cases and reaches 31.8% with an inlet velocity of 0.5 m/s, leading to significant increment of methane‐specific enthalpy at the preheating channel outlet. On the other hand, Rh(s)/O(s) ratios of catalytic surface and catalytic surface temperature in main reaction zone are enlarged by the preheating channels, facilitating methane adsorption at catalytic surface. Specially, most of fuels are consumed in a shorter distance with higher methane conversion speed, which brings benefits to promote combustion efficiency and may be helpful to inhibit the combustion instability in heat recirculation meso‐combustors.     

Controlling the morphology of poly(3‐hexylthiophene)/methanofullerene film through a dynamic‐cooling and freeze‐drying process

A dynamic‐cooling and freeze‐drying (DCFD) process has been applied to the fabrication of polymer solar cells. The dynamic‐cooling process allows poly(3‐hexylthiophene) molecules to aggregate in solution into a more organized structure during the cooling process; the freeze‐drying process prevents severe agglomeration of [6,6]‐phenyl‐C₆₁‐butyric acid methyl ester (PCBM) during the solvent removing process. Application of these two processes to the preparation of the poly(3‐hexylthiophene)/methanofullerene photoactive layer results in an enhanced poly(3‐hexylthiophene) aggregation and smaller PCBM agglomerates. Devices fabricated using the DCFD process generate 14% more in current density than those prepared by the spin‐coating process under AM1.5G illumination. © 2015 Society of Chemical Industry     

Optimal layout of additional facilities for minimization of domino effects based on worst-case scenarios

Accidents involving domino effects are more serious than other type of accidents. Although there have been studies on such accidents, it is still difficult to examine the actual factors and causes since the domino effect is influenced nonlinearly by factors involving flame, overpressure, and flying objects. We considered the case of adding new facilities to an existing system in a given site. The layout of new facilities suggests positions that minimize the domino effects, based on nonlinear optimization taking domino factors into account. We quantitatively calculated the domino risk of each facility through the concept of combined domino factors (flame, overpressure, and missile). Also, we identified variations of domino damage extent of the target system through comparison of the impacts of domino effect when additional facilities were installed. Simulated annealing was adopted for searching optimal positions. As a case study, we applied the proposed method to the case of adding DME storage tanks in the existing LPG charging facilities. The presented framework of the quantitative assessment of domino risk and safety standard for the layout of additional facilities would be useful for proper layout design for improved accident prevention.     

石灰石粉作为矿物掺合料对水泥胶砂性能的影响研究

本文以石灰石粉等量替代水泥、等量替代粉煤灰或矿渣粉,试验研究了石灰石粉对水泥胶砂流动度和强度的影响。试验结果表明:作为掺合料在砂浆中掺入10%~30%数量的石灰石粉是完全可行的,与单掺粉煤灰相比,石灰石粉与粉煤灰复掺作为掺合料的效果较好;而与矿渣粉相比,石灰石粉与矿渣粉复掺作为掺合料的效果较差。     

武器用光纤捷联惯导系统温度模型的研究

本文从光纤陀螺仪和加速度计两方面,对武器用光纤陀螺捷联惯导系统温度模型进行研究.论文首先对光纤陀螺仪温度模型构建的一般过程进行研究,并对加速度计及其I/F转换电路板串联系统的物理模型和数学模型进行了分析,最后对组合温度模型进行了实物验证和适应性验证,验证效果良好.