The purpose of this study was to identify and compare the degradation efficiencies of free and entrapped bacterial consortia(Staphylococcus capitis CP053957.1 and Achromobacter marplatensis MT078618.1)to different pol...The purpose of this study was to identify and compare the degradation efficiencies of free and entrapped bacterial consortia(Staphylococcus capitis CP053957.1 and Achromobacter marplatensis MT078618.1)to different polymers such as Sodium Alginate(SA),Sodium Alginate/Poly(Vinyl Alcohol)(SA/PVA),and Bushnell Haas Agar(BHA).In addition to SA and SA/PVA,which are cost-effective,non-toxic and have different functional groups,BHA,which is frequently encountered in laboratory-scale studies but has not been used as an entrapment material until now.Based on these,the polymers with different surface morphologies and chemical compositions were analyzed by SEM and FT-IR.While the petroleum removal efficiency was higher with the entrapped bacterial consortia than with the free one,BHA-entrapped bacterial consortium enhanced the petroleum removal more than SA and SA/PVA.Accordingly,the degradation rate of bacterial consortia entrapped with BHA was 2.039 day^(-1),SA/PVA was 1.560,SA was 0.993,the half-life period of BHA-entrapped bacterial consortia is quite low(t_(1/2)=0.339)compared with SA(t_(1/2)=0.444)and SA/PVA(t_(1/2)=0.697).The effects of the four main factors such as:amount of BHA(0.5,1,1.5,2,2.5,3 g),disc size(4,5,6,7,8 mm),inoculum concentration(1,2.5,5,7.5,10 mL),and incubation period on petroleum removal were also investigated.The maximum petroleum removal(94.5%)was obtained at≥2.5 mL of bacterial consortium entrapped in 2 g BHA with a 7 mm disc size at 168 h and the results were also confirmed by statistical analysis.Although a decrease was observed during the reuse of bacterial consortium entrapped in BHA,the petroleum removal was still above 50%at 10th cycle.Based on GC-MS analysis,the removal capacity of BHA-entrapped consortium was over 90%for short-chain n-alkanes and 80%for medium-chain n-alkanes.Overall,the obtained data are expected to provide a potential guideline in cleaning up the large-scale oil pollution in the future.Since there has been no similar study investigating petroleum removal with the bacterial consortia entrapped with BHA,this novel entrapment material can potentially be used in the treatment of petroleum pollution in advanced remediation studies.展开更多
The miscibility and crystallization of solution casting biodegradable poly（3-hydroxybuty- rate）/poly（ethylene succinate） （PHB/PES） blends was investigated by differential scanning calorimetry, rheology, and opti...The miscibility and crystallization of solution casting biodegradable poly（3-hydroxybuty- rate）/poly（ethylene succinate） （PHB/PES） blends was investigated by differential scanning calorimetry, rheology, and optical microscopy. The blends showed two glass transition temperatures and a depression of melting temperature of PHB with compositions in phase diagram, which indicated that the blend was partially miscible. The morphology observation supported this result. It was found that the PHB and PES can crystallize simultaneously or upon stepwise depending on the crystallization temperatures and compositions. The spherulite growth rate of PHB increased with increasing of PES content. The influence of compositions on the spherulitic growth rate for the partially miscible polymer blends was discussed.展开更多
A uniform to accelerated crystal twisting transition is observed in deuterate polyethylene/poly（ethylene-alt- propylene） （d-PE/PEP） blend films. And the band period is a function of initial d-PE concentration, que...A uniform to accelerated crystal twisting transition is observed in deuterate polyethylene/poly（ethylene-alt- propylene） （d-PE/PEP） blend films. And the band period is a function of initial d-PE concentration, quench depth and annealing time of phase separation. As Keith and Padden suggested, twisting of lamella is due to the unbalanced stress on its both sides, which can supply a satisfying explanation to banded spherulites formed in homogeneous systems. When it comes to d-PE/PEP blend system, in homogeneous 99% d-PE/PEP （weight fraction of d-PE） blend film, the formation of banded spherulite is observed as a result of uniform twisting of ribbon like d-PE lamellae along the radial direction. With the amorphous PEP piling up, it transfers into accelerated edge-on to fiat-on twisting due to crystallization assisted phase separation. The mechanism can be interpreted as following： d-PE molecules must inter-diffuse to the twisting growth front to continue the secondary nucleation and growth process. Meanwhile, the amorphous PEP molecules are rejected and accumulated at the twisting growth front. Once the d-PE lamella begins to twist because of unbalanced stress on both sides, the accumulated rubber phase at the growth front strengthens the unbalance and accelerates the edge-on to flat-on twisting. The concentration wave propagates further away with constant speed, and leads to concentric ring pattern with periodic nonuniform twisting along the radial direction. Since this is a kinetic effect, the band period can be controlled through initial d-PE concentration, quench depth and annealing time of phase separation. Our result shows that crystallization assisted phase separation can modify lamella growth kinetic pathway, thereby assisting concentric ring pattern formation.展开更多
By means of ultrasonic attenuation apparatus, the ultrasonic velocity and attenuation ofanhydride-cured epoxy resins (EP)/poly (ethylene oxide) (PEO) blends were measured on thebasis of pulse-echo method. It was found...By means of ultrasonic attenuation apparatus, the ultrasonic velocity and attenuation ofanhydride-cured epoxy resins (EP)/poly (ethylene oxide) (PEO) blends were measured on thebasis of pulse-echo method. It was found that the sonic velocity of the blends decreased as thetemperature increased, but attenuation coefficient increased and possessed a peak value. Largervelocity and smaller attenuation coefficient(α)can be obtained from perfect crosslinking networkstructures of pure DGEBA cured with phthalic anhydride(PA). As for cured DGEBA/PEO blendsystems,sonic velocity decreased as a function of PEO concentration,but attenuation coefficient(α) increased.展开更多
Electrorheological properties and creep-recovery behavior of polythiophene/polyoxymethylene-blend having PT（50%）/POM（50%） composition were investigated.Particle size,conductivity and dielectric values were measure...Electrorheological properties and creep-recovery behavior of polythiophene/polyoxymethylene-blend having PT（50%）/POM（50%） composition were investigated.Particle size,conductivity and dielectric values were measured to be 24.77μm,3.85×10^（-5） S·m^（-1） and 26.75,respectively.Sedimentation ratio was measured to be 64%at the end of 16 days.The effects of dispersed particle volume fraction,external electric field strength,shear rate,frequency and temperature on ER properties and storage modulus of PT/POM-blend/silicone oil（SO） suspensions were examined.Enhancement were observed in the electric field viscosities of the suspensions and thus they were classified as a smart material.Shear thinning non-Newtonian viscoelastic behavior was determined for PT/POM-blend/SO system.Further,time-dependent deformation was examined by creep-recovery tests and recoverable viscoelastic deformation established.展开更多
Ⅰ. INTRODUCTIONA central problem in computational complexity is whether or not the polynomial-time hierarchy is proper. Balcázar, Book and Schning have studied this problem by considering relativization with res...Ⅰ. INTRODUCTIONA central problem in computational complexity is whether or not the polynomial-time hierarchy is proper. Balcázar, Book and Schning have studied this problem by considering relativization with respect to sparse sets and proved the following results:展开更多
Porous poly(vinylidene fluoride)(PVDF)/poly(methyl methacrylate)(PMMA) blend five-bore hollow fiber membranes are prepared by wet phase inversion methods.In spinning these PVDF hollow fibers, N,N-dimethylacetamide(DMA...Porous poly(vinylidene fluoride)(PVDF)/poly(methyl methacrylate)(PMMA) blend five-bore hollow fiber membranes are prepared by wet phase inversion methods.In spinning these PVDF hollow fibers, N,N-dimethylacetamide(DMAc) and polyvinyl pyrrolidone(PVP) are used as the solvent and the non-solvent additive,respectively.The external coagulant uses water.The internal coagulants use water and DMAc-water solutions.The membranes are characterized in terms of water flux and molecular weight cut-off for the wet membranes.The cross-sectional structures are examined by scanning electron microscopy(SEM).The effects of polymer concentration and the internal coagulant on the permeation properties and membrane structures are examined keeping the bore liquid flow and air-gap constants.Relative high flux,rejection and strengh PVDF five-bore hollow fiber membranes could be prepared from the polymer concentration in dope solution at 17%of mass fraction,the air gap distance of 14 cm,and using 10%of mass fraction of DMAc solution as the internal coagulant at 13 mL/min of flow.展开更多
Blends of poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) (PHBHHx) and poly(butylene succinate-adipate) (PBSA), both biodegradable semicrystalline polyesters, were prepared with the ratio of PHBHHx/PBSA ranging from 80/...Blends of poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) (PHBHHx) and poly(butylene succinate-adipate) (PBSA), both biodegradable semicrystalline polyesters, were prepared with the ratio of PHBHHx/PBSA ranging from 80/20 to 20/80 by melt mixing method. Differential scanning calorimetry (DSC), thermogravimetry analysis (TGA), dynamic mechanical thermal analysis (DMA), polarizing optical microscopy (POM) and wide angle X-ray diffractometer (WAXD) were used to study the miscibility and crystallization behavior of PHBHHx/PBSA blends. Experimental results indicate that PHBHHx is immiscible with PBSA as shown by the almost unchanged glass transition temperature and the biphasic melt.展开更多
A central problem in the study of complexity is the measure of nonuniform complexity classes. BPPP/poly has been proved by Aldman, and EXPSPACEP/poly by Kannan. We propose the definition of approximate acceptance with...A central problem in the study of complexity is the measure of nonuniform complexity classes. BPPP/poly has been proved by Aldman, and EXPSPACEP/poly by Kannan. We propose the definition of approximate acceptance with which we discuss the nonuniform complexity of the K sized complete subgraph problem. The method of modal theory is used and the K sized complete subgraph problemP/poly, co NPP/poly and NPP/poly is proved. This paper solves the Karp Lipton′s open problem: “NPP/poly?”展开更多
文摘The purpose of this study was to identify and compare the degradation efficiencies of free and entrapped bacterial consortia(Staphylococcus capitis CP053957.1 and Achromobacter marplatensis MT078618.1)to different polymers such as Sodium Alginate(SA),Sodium Alginate/Poly(Vinyl Alcohol)(SA/PVA),and Bushnell Haas Agar(BHA).In addition to SA and SA/PVA,which are cost-effective,non-toxic and have different functional groups,BHA,which is frequently encountered in laboratory-scale studies but has not been used as an entrapment material until now.Based on these,the polymers with different surface morphologies and chemical compositions were analyzed by SEM and FT-IR.While the petroleum removal efficiency was higher with the entrapped bacterial consortia than with the free one,BHA-entrapped bacterial consortium enhanced the petroleum removal more than SA and SA/PVA.Accordingly,the degradation rate of bacterial consortia entrapped with BHA was 2.039 day^(-1),SA/PVA was 1.560,SA was 0.993,the half-life period of BHA-entrapped bacterial consortia is quite low(t_(1/2)=0.339)compared with SA(t_(1/2)=0.444)and SA/PVA(t_(1/2)=0.697).The effects of the four main factors such as:amount of BHA(0.5,1,1.5,2,2.5,3 g),disc size(4,5,6,7,8 mm),inoculum concentration(1,2.5,5,7.5,10 mL),and incubation period on petroleum removal were also investigated.The maximum petroleum removal(94.5%)was obtained at≥2.5 mL of bacterial consortium entrapped in 2 g BHA with a 7 mm disc size at 168 h and the results were also confirmed by statistical analysis.Although a decrease was observed during the reuse of bacterial consortium entrapped in BHA,the petroleum removal was still above 50%at 10th cycle.Based on GC-MS analysis,the removal capacity of BHA-entrapped consortium was over 90%for short-chain n-alkanes and 80%for medium-chain n-alkanes.Overall,the obtained data are expected to provide a potential guideline in cleaning up the large-scale oil pollution in the future.Since there has been no similar study investigating petroleum removal with the bacterial consortia entrapped with BHA,this novel entrapment material can potentially be used in the treatment of petroleum pollution in advanced remediation studies.
基金ACKNOWLEDGMENT This work was supported by the Key Science Foundation of Education Ministry of China and the Anhui Science Foundation.
文摘The miscibility and crystallization of solution casting biodegradable poly（3-hydroxybuty- rate）/poly（ethylene succinate） （PHB/PES） blends was investigated by differential scanning calorimetry, rheology, and optical microscopy. The blends showed two glass transition temperatures and a depression of melting temperature of PHB with compositions in phase diagram, which indicated that the blend was partially miscible. The morphology observation supported this result. It was found that the PHB and PES can crystallize simultaneously or upon stepwise depending on the crystallization temperatures and compositions. The spherulite growth rate of PHB increased with increasing of PES content. The influence of compositions on the spherulitic growth rate for the partially miscible polymer blends was discussed.
基金financially supported by the National Natural Science Foundation of China(Nos.50930003 and 21174152)
文摘A uniform to accelerated crystal twisting transition is observed in deuterate polyethylene/poly（ethylene-alt- propylene） （d-PE/PEP） blend films. And the band period is a function of initial d-PE concentration, quench depth and annealing time of phase separation. As Keith and Padden suggested, twisting of lamella is due to the unbalanced stress on its both sides, which can supply a satisfying explanation to banded spherulites formed in homogeneous systems. When it comes to d-PE/PEP blend system, in homogeneous 99% d-PE/PEP （weight fraction of d-PE） blend film, the formation of banded spherulite is observed as a result of uniform twisting of ribbon like d-PE lamellae along the radial direction. With the amorphous PEP piling up, it transfers into accelerated edge-on to fiat-on twisting due to crystallization assisted phase separation. The mechanism can be interpreted as following： d-PE molecules must inter-diffuse to the twisting growth front to continue the secondary nucleation and growth process. Meanwhile, the amorphous PEP molecules are rejected and accumulated at the twisting growth front. Once the d-PE lamella begins to twist because of unbalanced stress on both sides, the accumulated rubber phase at the growth front strengthens the unbalance and accelerates the edge-on to flat-on twisting. The concentration wave propagates further away with constant speed, and leads to concentric ring pattern with periodic nonuniform twisting along the radial direction. Since this is a kinetic effect, the band period can be controlled through initial d-PE concentration, quench depth and annealing time of phase separation. Our result shows that crystallization assisted phase separation can modify lamella growth kinetic pathway, thereby assisting concentric ring pattern formation.
文摘By means of ultrasonic attenuation apparatus, the ultrasonic velocity and attenuation ofanhydride-cured epoxy resins (EP)/poly (ethylene oxide) (PEO) blends were measured on thebasis of pulse-echo method. It was found that the sonic velocity of the blends decreased as thetemperature increased, but attenuation coefficient increased and possessed a peak value. Largervelocity and smaller attenuation coefficient(α)can be obtained from perfect crosslinking networkstructures of pure DGEBA cured with phthalic anhydride(PA). As for cured DGEBA/PEO blendsystems,sonic velocity decreased as a function of PEO concentration,but attenuation coefficient(α) increased.
基金financially supported by Turkish Scientific and Technological Research Council(No.107 T 711)
文摘Electrorheological properties and creep-recovery behavior of polythiophene/polyoxymethylene-blend having PT（50%）/POM（50%） composition were investigated.Particle size,conductivity and dielectric values were measured to be 24.77μm,3.85×10^（-5） S·m^（-1） and 26.75,respectively.Sedimentation ratio was measured to be 64%at the end of 16 days.The effects of dispersed particle volume fraction,external electric field strength,shear rate,frequency and temperature on ER properties and storage modulus of PT/POM-blend/silicone oil（SO） suspensions were examined.Enhancement were observed in the electric field viscosities of the suspensions and thus they were classified as a smart material.Shear thinning non-Newtonian viscoelastic behavior was determined for PT/POM-blend/SO system.Further,time-dependent deformation was examined by creep-recovery tests and recoverable viscoelastic deformation established.
文摘Ⅰ. INTRODUCTIONA central problem in computational complexity is whether or not the polynomial-time hierarchy is proper. Balcázar, Book and Schning have studied this problem by considering relativization with respect to sparse sets and proved the following results:
基金the China Postdoctoral Science Foundation (No.20110490645)the Science Foundation of Shanghai(No.11ZR1400800)
文摘Porous poly(vinylidene fluoride)(PVDF)/poly(methyl methacrylate)(PMMA) blend five-bore hollow fiber membranes are prepared by wet phase inversion methods.In spinning these PVDF hollow fibers, N,N-dimethylacetamide(DMAc) and polyvinyl pyrrolidone(PVP) are used as the solvent and the non-solvent additive,respectively.The external coagulant uses water.The internal coagulants use water and DMAc-water solutions.The membranes are characterized in terms of water flux and molecular weight cut-off for the wet membranes.The cross-sectional structures are examined by scanning electron microscopy(SEM).The effects of polymer concentration and the internal coagulant on the permeation properties and membrane structures are examined keeping the bore liquid flow and air-gap constants.Relative high flux,rejection and strengh PVDF five-bore hollow fiber membranes could be prepared from the polymer concentration in dope solution at 17%of mass fraction,the air gap distance of 14 cm,and using 10%of mass fraction of DMAc solution as the internal coagulant at 13 mL/min of flow.
基金The National Natural Science Foundation of China (No. 20374032) and Tianjin Science and Technology Key Project (No. 05YFSZSF02200)
文摘Blends of poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) (PHBHHx) and poly(butylene succinate-adipate) (PBSA), both biodegradable semicrystalline polyesters, were prepared with the ratio of PHBHHx/PBSA ranging from 80/20 to 20/80 by melt mixing method. Differential scanning calorimetry (DSC), thermogravimetry analysis (TGA), dynamic mechanical thermal analysis (DMA), polarizing optical microscopy (POM) and wide angle X-ray diffractometer (WAXD) were used to study the miscibility and crystallization behavior of PHBHHx/PBSA blends. Experimental results indicate that PHBHHx is immiscible with PBSA as shown by the almost unchanged glass transition temperature and the biphasic melt.
文摘A central problem in the study of complexity is the measure of nonuniform complexity classes. BPPP/poly has been proved by Aldman, and EXPSPACEP/poly by Kannan. We propose the definition of approximate acceptance with which we discuss the nonuniform complexity of the K sized complete subgraph problem. The method of modal theory is used and the K sized complete subgraph problemP/poly, co NPP/poly and NPP/poly is proved. This paper solves the Karp Lipton′s open problem: “NPP/poly?”
基金Project supported by the Science and Technology Program of Zhejiang Province(No.2013C31146)the State Key Laboratory of Chemical Engineering(No.SKL-Ch E-12D02)+1 种基金the Science and Technology Innovation Team of Ningbo(No.2011B82002)the Fundamental Research Funds for the Central Universities(No.2015FZA4025),China
