矩形截面气升式环流反应器中非牛顿流体的气含率与传质系数的研究

研究了一种矩形截面气升式环流反应器,用幂律τ=η_ογ~n(n<1)来表示流体流变学特性的变化.在这类反应器中,假塑性非牛顿流体的气含率ε_g与传质系数K_La的变化规律可用半经验关联式表示ε_g=0.2535(η_ο5000~(n-1))~(-0.161)(1+A_d/A_r)~(-0.434)u_(gr)~(0.856-0.161n)K_La=0.0192(η_ο5000~(n-1))~(-0.902)(1+A_d/A_r)~(-1.228)u_(gr)~(1.955-0.902n)并讨论了该类反应器结构及运行状况,流体性质变化时,反应器传质动力学特性、流动特性和操作弹性变化的规律.     

气升式外循环淤浆反应器的气含率和传质的研究

在气升式外循环环流反应器中,对空气-水两相系统的气含率■_(go)和气-液氧体积传质系数进行了研究,获得关联式:■_(go)=1.384(u_G/(u_G+u'_L)~(0.34)u_G~(0.71)k_Lα=0.0463(u_G/(u_G+u'_L)~(0.24)u_G~(0.52)对空气-水-α-氧化铝三相淤浆系统,采用丝网过滤将催化剂留于反应器上升管中。此时,上升管中气含率■_(go)和传质系 k_La可用下面公式来计算:■=1.384/(1+0.504■_s~(0.13))(u_G/(u_G+u'_L))~(0.34)u_G~(0.71) (■_s=0.001～0.05)■     

正方形流化床结构参数改变和内构件强化的数值模拟解析

借助数值模拟方法分析多功能结构反应器内部的流体力学行为,可以减少放大实验的批次,获知反应器结构关于废水生物处理功能区划的描述。以土建工程便利的正方形流化床为研究对象,通过改变下降区和上升区面积比(A_d/A_r)、环隙过流区和上升区面积比(A_b/A_r)、导流筒与液面距离和导流筒高度比(H_t/H_(dt))3种结构参数,并添加十字型挡板和漏斗型导流板两种内构件,考察各种状态下液速(U_L)和气含率(ε_G)的流体特性响应行为,在实现高效氧传质、节能与短程硝化反硝化方面寻找结构优化和操作条件优化的空间。结果表明:A_d/A_r的改变主要影响液速的分布及其峰值,取1.25;A_b/A_r主要影响流化床底部的液速的大小和方向,取1.2为宜;H_t/H_(dt)主要影响导流筒上方液体受到的有效整流作用,取值1/8。在结构参数优化的基础上,两种内构件对流化床的耦合作用能够满足生化流化床技术对低液速和各生化阶段气含率的需求。结果证明了采用CFD数值模拟可以实现废水处理不同目标体系下反应器功能化开发,结构参数优化和内构件置入的正方形流化床反应器具有强化传质与区域功能化的特征,两个方面的结合可以实现能量高效利用和降低研发成本的目标。     

合成己二腈反应技术——(Ⅳ)鼓泡外循环反应器中气、液流动特性的研究

根据己二酸液相氨化制己二腈反应的特点,提出了一个由鼓泡气提塔和外循环降膜反应器组合的新型复合反应器。实验研究了气液两相的流动特性,获得了在该新型反应器中,在高气速操作下,气含率的经验关联式:ε_G=0.544u_G~(0.47)(72/σ)~(0.11)(ρ_L/1)~(0.25)在较宽的气速范围内测定了液相循环速度,证实了存在最小起始循环气速,得出了描述表观液相循环速度的关联式:u_(LR)=0.20(H_S/L)~(1.8)(u_G—u_(GS))~(0.65)(1/ρ_L)u_(GS)=3.65[1-(H_S/L)]~(2.13)(σ/72)~(0.234)(1/ρ_L)~(0.532)并对该反应器的液相总体 RTD 进行了测定,得出该复合反应器相当于1.4～2个釜的串连。     

气升式生物反应器中培养液-絮凝细胞颗粒-空气三相系统气含率的研究

首先以惰性离子交换树脂模拟絮凝细胞颗粒,以水模拟低粘度培养液,在有效容积12L的气升式生物反应器中研究了气升管内三相系统的气含率,获得了关联式ε_g=(1-0.825U_t~(-0.0233)d~(0.0134))/(1+U_(sL)/U_g进而以絮凝法固定化酵母酒精发酵过程中的絮凝酵母颗粒一培养液这样的真实物系,对模拟物系研究建立的关联式进行修正,得到ε_g=(1-0.783U_t~(-0.0233)d~(0.0134))/(1+U_(sL)/U_g上述气含率的关联式与反应器环流系统的动量方程式相结合,可以预测反应器中流体力学基本参数.     

气升式生物反应器中培养液-絮凝细胞颗粒-空气三相系统气含率的研究

首先以惰性离子交换树脂模拟絮凝细胞颗粒,以水模拟低粘度培养液,在有效容积12L的气升式生物反应器中研究了气升管内三相系统的气含率,获得了关联式ε_g=(1-0.825U_t~(-0.0233)d~(0.0134))/(1+U_(sL)/U_g进而以絮凝法固定化酵母酒精发酵过程中的絮凝酵母颗粒一培养液这样的真实物系,对模拟物系研究建立的关联式进行修正,得到ε_g=(1-0.783U_t~(-0.0233)d~(0.0134))/(1+U_(sL)/U_g上述气含率的关联式与反应器环流系统的动量方程式相结合,可以预测反应器中流体力学基本参数.     

气液喷射式环流反应器气含率及传质比表面积的研究

研究了气速、液速对喷射式环流反应器气-液传质比表面积以及全塔、导流管和环隙部分的平均气含率的影响。提出将喷射式环流反应器中传递性能参数随操作条件的变化规律进行分区研究可简化放大过程。根据实验数据和文献数据,获得了计算敏感区域全塔平均气含率(?)和气液传质比表面积a_R的关联式: (?)=7.18×10~(-4)U_g~(0.55)Re_1~(1.24)D~(-0.64) a_R=644U_(g)~(0.44)(ρ_L/V_R)~(0.46)     

三相淤浆床冷态特性研究——气体—石腊油—催化剂系统

本文研究了气体—石腊油—催化剂三相体系在淤浆床反应器中的流体力学特性,考察了各种因素对气含率和压降的影响,并回归得到如下关联式:ε_g=0.1152u_g~(0.41)c_g~(0.093)ρ~(0.018)。     

在小型和大型气、固流化床中等密度宽筛分固体颗粒的分离

在直径为0.213 m 的小型园柱气固流化床中和一个大型的0.61×0.61m 的正方形气固流化床中研究了相同密度不同粒径的二元系统混合物的分离过程。粒径比在1到14,考察了固体颗粒不同配比对于临界速度的影响,获得基本上符合 Rice 等的计算式。M=x/=[1+exp(-F')]~(-1)式中F'=±■·exp(u/u_(To))当 M=0.5时的临界速度为:u_(To)=K(u_(mf·f)·u_(mf.J))~m·(d_R)~n当床层气速小于大颗粒的最小流化速度时可获得完全流化时的最小流化速度 u_(cf)u_J-u_(cf)/u_J=(ū_(mf)-u_J/u_J)~2本研究对于等密度宽筛分二元粒子混合物系统,预测值与实验值比较吻合。     

下喷式环流反应器的气含率特性

本文以空气-水和空气-CMC 水溶液为实验体系,研究了气速、液速、体系物性以及反应器结构尺寸等参数对下喷式环流反应器全塔平均气含率的影响,得出最优的导流筒直径与反应器直径之比为0.57,提出了牛顿型与粘度较低的非牛顿型流体体系中气含率的计算关联式:■_G=0.3157[(D_E/D_R)~2-1.14D_E/D_R+0.55]~(-3.312)·n~(0.9142)·((ρ_G·μ_G)/(ρ_L·μ_L))~(0.01899)·Fr_■~(0.3884)·Fr_L~(0.2918)     

Insect antifeedant properties of anthranoids from the genusVismia

Vismiones and ferruginins, representatives of a new class of lypophilic anthranoids from the genusVismia were found to inhibit feeding in larvae of species ofSpodoptera, Heliothis, and inLocusta migratoria.     

Direct observation of freeze-thaw instability of latex coatings via high pressure freezing and cryogenic SEM

Despite its industrial importance, the subject of freeze-thaw (F/T) stability of latex coatings has not been studied extensively. There is also a lack of fundamental understanding about the process and the mechanisms through which a coating becomes destabilized. High pressure (2100 bar) freezing fixes the state of water-suspended particles of polymer binder and inorganic pigments without the growth of ice crystals during freezing that produce artifacts in direct imaging scanning electron microscopy (SEM) of fracture surfaces of frozen coatings. We show that by incorporating copolymerizable functional monomers, it is possible to achieve F/T stability in polymer latexes and in low-VOC paints, as judged by the microstructures revealed by the cryogenic SEM technique. Particle coalescence as well as pigment segregation in F/T unstable systems are visualized. In order to achieve F/T stability in paints, latex particles must not flocculate and should provide protection to inorganic pigment and extender particles. Because of the unique capabilities of the cryogenic SEM, we are able to separate the effects of freezing and thawing, and study the influence of the rate of freezing and thawing on F/T stability. Destabilization can be caused by either freezing or thawing. A slow freezing process is more detrimental to F/T stability than a fast freezing process; the latter actually preserves suspension stability during freezing. Presented at the 82nd Annual Meeting of the Federation of Societies for Coatings Technology, October 27–29, 2004 in Chicago, IL. Tied for first place in The John A. Gordon Best Paper Competition.     

Ethanol and (−)-α-Pinene: Attractant Kairomones for Bark and Ambrosia Beetles in the Southeastern US

In 2002–2004, we examined the flight responses of 49 species of native and exotic bark and ambrosia beetles (Coleoptera: Scolytidae and Platypodidae) to traps baited with ethanol and/or (−)-α-pinene in the southeastern US. Eight field trials were conducted in mature pine stands in Alabama, Florida, Georgia, North Carolina, and South Carolina. Funnel traps baited with ethanol lures (release rate, about 0.6 g/day at 25–28°C) were attractive to ten species of ambrosia beetles (Ambrosiodmus tachygraphus, Anisandrus sayi, Dryoxylon onoharaensum, Monarthrum mali, Xyleborinus saxesenii, Xyleborus affinis, Xyleborus ferrugineus, Xylosandrus compactus, Xylosandrus crassiusculus, and Xylosandrus germanus) and two species of bark beetles (Cryptocarenus heveae and Hypothenemus sp.). Traps baited with (−)-α-pinene lures (release rate, 2–6 g/day at 25–28°C) were attractive to five bark beetle species (Dendroctonus terebrans, Hylastes porculus, Hylastes salebrosus, Hylastes tenuis, and Ips grandicollis) and one platypodid ambrosia beetle species (Myoplatypus flavicornis). Ethanol enhanced responses of some species (Xyleborus pubescens, H. porculus, H. salebrosus, H. tenuis, and Pityophthorus cariniceps) to traps baited with (−)-α-pinene in some locations. (−)-α-Pinene interrupted the response of some ambrosia beetle species to traps baited with ethanol, but only the response of D. onoharaensum was interrupted consistently at most locations. Of 23 species of ambrosia beetles captured in our field trials, nine were exotic and accounted for 70–97% of total catches of ambrosia beetles. Our results provide support for the continued use of separate traps baited with ethanol alone and ethanol with (−)-α-pinene to detect and monitor common bark and ambrosia beetles from the southeastern region of the US.     

Methyl 2,4,6-decatrienoates Attract Stink Bugs and Tachinid Parasitoids

Halyomorpha halys (Stål) (Pentatomidae), called the brown marmorated stink bug (BMSB), is a newly invasive species in the eastern USA that is rapidly spreading from the original point of establishment in Allentown, PA. In its native range, the BMSB is reportedly attracted to methyl (E,E,Z)-2,4,6-decatrienoate, the male-produced pheromone of another pentatomid common in eastern Asia, Plautia stali Scott. In North America, Thyanta spp. are the only pentatomids known to produce methyl 2,4,6-decatrienoate [the (E,Z,Z)-isomer] as part of their pheromones. Methyl 2,4,6-decatrienoates were field-tested in Maryland to monitor the spread of the BMSB and to explore the possibility that Thyanta spp. are an alternate host for parasitic tachinid flies that use stink bug pheromones as host-finding kairomones. Here we report the first captures of adult and nymph BMSBs in traps baited with methyl (E,E,Z)-2,4,6-decatrienoate in central Maryland and present data verifying that the tachinid, Euclytia flava (Townsend), exploits methyl (E,Z,Z)-2,4,6-decatrienoate as a kairomone. We also report the unexpected finding that various isomers of methyl 2,4,6-decatrienoate attract Acrosternum hilare (Say), although this bug apparently does not produce methyl decatrienoates. Other stink bugs and tachinids native to North America were also attracted to methyl 2,4,6-decatrienoates. These data indicate there are Heteroptera in North America in addition to Thyanta spp. that probably use methyl 2,4,6-decatrienoates as pheromones. The evidence that some pentatomids exploit the pheromones of other true bugs as kairomones to find food or to congregate as a passive defense against tachinid parasitism is discussed.     

2007～2008年世界塑料工业进展

收集了2007年7月～2008年6月世界塑料工业的相关资料,介绍了2007～2008年国外塑料工业的发展情况,提供了世界塑料产量、消费量及全球各类树脂的需求量及产能情况.按通用热塑性树脂(聚乙烯、聚丙烯、聚苯乙烯、聚氯乙烯、ABS树脂)、工程塑料(尼龙、聚碳酸酯、聚甲醛、热塑性聚酯、聚苯醚)、特种工程塑料(聚苯·硫醚、液晶聚合物、聚醚醚酮)、通用热固性树脂(酚醛、聚氨酯、不饱和聚酯树脂、环氧树脂)不同品种的顺序,对树脂的产量、消费量、供需状况及合成工艺、产品应用开发、树脂品种的延伸及应用的进一步扩展等技术作了详细介绍.     

2005～2006年国外塑料工业进展

收集了2005年7月～2006年6月国外塑料工业的相关资料,介绍了2005—2006年国外塑料工业的发展情况。提供了世界塑料产量、消费量及全球各类树脂生产量以及各国塑料制品的进出口情况。作为对比,介绍了中国塑料的生产情况。按通用热塑性树脂（聚乙烯、聚丙烯、聚苯乙烯、聚氯乙烯、ABS树脂）、工程塑料（聚酰胺、聚碳酸酯、聚甲醛、热塑性聚酯、聚苯醚）、通用热固性树脂（酚醛、聚氨酯、不饱和树脂、环氧树脂）、特种工程塑料（聚苯硫醚、液晶聚合物、聚醚醚酮）的品种顺序,对树脂的产量、消费量、供需状况及合成工艺、产品开发、树脂品种的延伸及应用的扩展作了详细的介绍。