Commercial polypropylene microfiltration membranes (PPMM) and biaxial oriented polypropylene (BOPP) films were ozonated in aqueous and gaseous media, respectively, followed by graft polymerization of acryl amide (AAm), hydroxyethyl methacrylate (HEMA), and polyethylene glycol (PEG) to improve their surface hydrophilicity. The efficiency of ozonation conducted in the gaseous and aqueous phases was compared, the gaseous phase ozonation was found slightly more effective in generating peroxide groups, while the aqueous phase ozonation was found more effective in grafting polymerization. Scavengers were added to the aqueous phase ozonation, results indicated that both the radical groups and the molecule ozone contributed to the peroxide generation. The free radical groups contributed maximum 25% and 32% for ozonation of PPMM and BOPP, respectively, and the molecule ozone contributed the percentage remaining. Results also showed that the concentration of peroxides generated on the surfaces of PPMM or BOPP increased with the applied ozone dose and ozonation time in both phases. Copper sulfate hydrate (CuSO4·5H2O) and ferric chloride hydrate (FeCl3·6H2O) were added in the aqueous phase ozonation as homogenous catalysts, results showed that the peroxide generation rate of PPMM and BOPP was improved comparing to that of ozonation without catalyst. The peroxide generation of PPMM showed 17% increase by adding copper catalyst, and 16% increase in peroxide generation was observed in ferric catalyzed ozonation of BOPP. The mechanism of the aqueous phase ozonation was investigated, along with that of catalytic ozonation. An enhanced radical process was found for catalytic ozonation in this study. The hydrophilicity of PPMM and BOPP was improved by graft polymerization of AAm, HEMA and PEG initiated by the peroxides. The aqueous phase ozonation was found more effective in grafting. A washing test was conducted using distilled water blending with 10% isopropyl alcohol. When the ozonated membranes and films were washed and compared to the non-washed ones, it was found that the gaseous phase ozonated PPMM or BOPP lost more peroxides than their aqueous phase counterpart after washing. The washing tests showed that the aqueous phase ozonation could induce a better graft polymerization, because part of the tested peroxides from the gaseous ozonation was washed away in the cleaning and grafting process. The improved hydrophilicity of PPMM was indicated by the contact angle reduction from 129° to 91° for AAm grafting; from 126° to 74° for HEMA grafting; and from 126° to 88° for PEG grafting; Fourier Transform Infrared (FTIR) measurements showed additional peaks of functional groups, such as amine (N-H) and amide (–N-C=O) functional groups from the grafted AAm (CH2=CH-CO-NH2); and the Scanning Electron Microscope (SEM) images confirmed amorphicity changes of the graft polymerization. X-ray Diffraction (XRD) diffractogram revealed the crystallinity changes of ozonated and grafted PPMM. Bovine serum albumin (BSA) was used to test the filtration performance of virgin and grafted membranes, the filtration tests demonstrated the improvement in anti-fouling effect of the modified PPMM; and the SEM images of the fouled and washed membranes revealed the pore blockage and recovering on the surface. The hydrophilicity of the grafted BOPP was also improved, indicated by the contact angle reduction of AAm grafted film from 80° to 56°. The FTIR showed additional peaks of N-H and –N-C=O functional groups of grafted AAm. SEM images indicated amorphicity changes of the graft polymerization. The film modified by the aqueous phase ozonation showed its advantages of better graft polymerization, hydrophilicity, and protein adsorption. The results of this study positively impacted the industrial using of PPMM to elongate its duration time of filtration, and improved the applications of BOPP in biomedical areas

In this study, three polymer films - high density polyethylene (HDPE), biaxial oriented polypropylene (BOPP) and biaxial oriented polyethylene terephthalate (PET) were oxidized by ozone in distilled water and in the gaseous phase in a specially designed reactor. Ozonation was conducted using different reaction times, applied ozone doses and pH values. Peroxides were generated by ozonation on the surfaces of polymers. Then the peroxide-induced graft polymerixation of hydrophilic monomers improves the biocompatibility of the polymer surfaces. These three films are currently in extensive use, the modified polymer films can be applied more in organic materials packaging and medical fields. These three films were all found to react with ozone to generate peroxides both in distilled water and in gaseous phase. When comparing the peroxide generation rates in distilled water and in ozone gas mixture, it was found that the peroxide generation rates of BOPP and PET in the gaseous phase ozonation were faster than the peroxide generation rates in the aqueous phase ozonation; but the peroxide generation rate of HDPE showed a different trend: its peroxide generation rate in distilled water was faster than when using the ozone mixture in the gaseous phase. Further, among the three polymer films, HDPE obtained the fastest peroxide generation rate in distilled water, while BOPP has the fastest peroxide generation rate in gas phase. The tensile strength and elongation of untreated and ozone treated films were examined. The tensile strength and elongation decreased with increasing ozonation time. For both the aqueous and ozone gas mixtures, the order in which the three polymer films decreased in tensile strength and elongation were: HDPE>BOPP>PETE; but the tensile stength and elongation of BOPP and PET dropped faster when using the ozone gas mixture than when using the aqueous ozone. The results were the opposite of HDPE. After the reaction conditions were investigated, that using the 1.0-wt‰ applied ozone dose and 1.0-hr reaction time was found to be optimal, both to obtain peroxides and to maintain good mechanical strength. After investigation of the reactions with different pH values, it was found that the peroxide density decreased slightly as the pH volume increased. Finally, the ozone-induced graft polymerization of Acryamide (AAm) significantlly increased the hydrophilicity of HDPE films, the FTIR and SEM analysis confirmed the successful graft polymerization of AAm.

Pilot should control the aircraft manually when encountering low altitude wind shear during takeoff and landing. For wind shear escape and flight safety research, an effective human pilot model together with wind shear and flight dynamics model should be built with high fidelity. A skill-based human pilot model was built which can describe pilots’ characteristics such as experiences, skills, emotions, reaction abilities, etc. A fuzzy controller was designed for lateral and longitudinal escape control in pilot model. Since single pilot could not represent a group of pilots’ control behavior, some of the model parameters were set to be stochastic, then the Monte Carlo method was adopted to obtain a numerical approximation of safety analysis results. With the probabilistic pilot model, escape strategies and safety analysis can be studied by simulation with high fidelity.

In this study, three polymer films - high density polyethylene (HDPE), biaxial oriented polypropylene (BOPP) and biaxial oriented polyethylene terephthalate (PET) were oxidized by ozone in distilled water and in the gaseous phase in a specially designed reactor. Ozonation was conducted using different reaction times, applied ozone doses and pH values. Peroxides were generated by ozonation on the surfaces of polymers. Then the peroxide-induced graft polymerixation of hydrophilic monomers improves the biocompatibility of the polymer surfaces. These three films are currently in extensive use, the modified polymer films can be applied more in organic materials packaging and medical fields. These three films were all found to react with ozone to generate peroxides both in distilled water and in gaseous phase. When comparing the peroxide generation rates in distilled water and in ozone gas mixture, it was found that the peroxide generation rates of BOPP and PET in the gaseous phase ozonation were faster than the peroxide generation rates in the aqueous phase ozonation; but the peroxide generation rate of HDPE showed a different trend: its peroxide generation rate in distilled water was faster than when using the ozone mixture in the gaseous phase. Further, among the three polymer films, HDPE obtained the fastest peroxide generation rate in distilled water, while BOPP has the fastest peroxide generation rate in gas phase. The tensile strength and elongation of untreated and ozone treated films were examined. The tensile strength and elongation decreased with increasing ozonation time. For both the aqueous and ozone gas mixtures, the order in which the three polymer films decreased in tensile strength and elongation were: HDPE>BOPP>PETE; but the tensile stength and elongation of BOPP and PET dropped faster when using the ozone gas mixture than when using the aqueous ozone. The results were the opposite of HDPE. After the reaction conditions were investigated, that using the 1.0-wt‰ applied ozone dose and 1.0-hr reaction time was found to be optimal, both to obtain peroxides and to maintain good mechanical strength. After investigation of the reactions with different pH values, it was found that the peroxide density decreased slightly as the pH volume increased. Finally, the ozone-induced graft polymerization of Acryamide (AAm) significantlly increased the hydrophilicity of HDPE films, the FTIR and SEM analysis confirmed the successful graft polymerization of AAm.

Low altitude microburst wind shear would do harm to aircrafts’ takeoff and landing. In order to analyze flight safety and advise better escape strategies, a mathematical model was built with high fidelity by a vortex ring based microburst model and a flight dynamics model with wind effects. A human pilot model which can describe characteristics of pilots such as skills, experiences, emotion, etc was embedded into the dynamics model. Since the key parameters of the microburst wind shear model and pilot model were set to be stochastic, the Monte Carlo method was adopted to obtain a numerical approximation of the probability density function of the minimum altitude and the F-factors for flight safety analysis.