斜孔梯形浮阀的横向间距对其流体力学性能的影响

采用空气-水系统,在500 mm×500 mm的方形塔内,在不同的斜孔梯形浮阀的横向间距下对导向梯形浮阀塔板的流体力学进行了实验研究,测定了塔板压降、泄漏和雾沫夹带.并应用空气-水-CO2系统,在不同的横向间距下测定了斜孔梯形浮阀塔板的传质效率.实验结果表明,斜孔梯形浮阀塔板的横向间距对其流体力学和传质性能有显著的影响.     

升程对导向梯形浮阀的塔板流体力学及传质效率的影响

采用空气-水系统,在500mm×500mm的方形塔内,对导向梯形浮阀塔板在不同的浮阀升程下的流体力学进行实验研究,测定塔板压降、泄漏和雾沫夹带。并采用空气-水-CO2系统,在不同的升程下测定斜孔梯形浮阀塔板的传质效率。实验结果表明,导向梯形浮阀塔板的升程对其流体力学和传质性能有显著的影响。     

导向梯形浮阀的升程对其塔板性能影响

为使导向梯形浮阀在工业应用时,选取浮阀升程有可靠的参考数据,针对导向梯形浮阀的升程这一结构参数进行试验研究。采用空气-水系统,在500 mm×500 mm的方形塔内,对不同浮阀的升程对导向梯形浮阀塔板的流体力学进行了实验研究,测定了塔板压降、泄漏和雾沫夹带。并应用空气-水-CO2系统,在不同的升程下测定了斜孔梯形浮阀塔板的传质效率。实验结果表明,导向梯形浮阀塔板的升程对其流体力学和传质性能有显著的影响,并在确定的条件下有最佳值。     

微分浮阀塔板的研究和应用

应用空气 -水系统 ,在直径 6 0 0 mm的塔内 ,对微分浮阀塔板的流体力学进行了实验研究 ,测定了临界孔速、塔板压降、雾沫夹带率和液体泄漏率。应用空气 -水 -氧气物系 ,测定了微分浮阀塔板的传质效率。并与 F1型浮阀塔板进行了对比实验研究。实验结果表明 :微分浮阀塔板比 F1型浮阀塔板具有更好的流体力学和传质性能 ,并对实验数据进行了关联 ,获得了计算临界孔速、塔板压降、雾沫夹带率和泄漏点孔速的关联式 ,可用于微分浮阀塔板的设计计算。文中还介绍了微分浮阀塔板的工业应用情况     

新型固定阀塔板的流体力学和传质性能研究

提供了一种阀盖两侧具有向下弯曲折边的新型固定阀。在内径为500mm的有机玻璃塔内,以空气水为物系,研究了其流体力学性能;在内径为300mm的不锈钢塔内,以乙醇水为物系,常压全回流情况下,研究了其传质性能。研究结果表明:新型固定阀塔板的板压降略高于筛孔塔板,比F1 浮阀塔板小得多,雾沫夹带量小,雾沫夹带液泛点阀(筛)孔动能因子均比筛孔塔板、F1 浮阀塔板大,漏液量较小,漏液点阀(筛)孔动能因子比筛孔塔板低,比F1 浮阀塔板高,传质效率与F1 浮阀塔板相当。     

组合导向浮阀塔板

在1600mm×400mm的矩形塔内,分别利用空气——水和空气——水——CO_2系统,对组合导向浮阀塔板的流体力学和传质性能进行了实验研究。实验结果表明,适当配比的组合导向浮阀塔板具有良好的流体力学和传质性能。     

B型导向浮阀塔板实验研究

为增大导向浮阀塔板对液体流动的推动力,在1600 mm×400 mm实验塔内,利用空气-水系统,对B型导向浮阀塔板进行实验研究。与导向浮阀塔板相比,它具有更好的流体力学性能和更大的液体负荷适用范围。实验研究和工业应用表明,B型导向浮阀塔板具有处理能力约提高20%、塔板效率约提高10%、操作弹性约提高30%等突出特点,用于蒸馏、吸收、汽提等传质过程,可获得良好效果。     

双层导向浮阀塔板的流体力学与传质性能研究

介绍了一种新型塔板--双层导向浮阀塔板,该塔板综合了国内流行的导向条阀与国外广泛使用的微型固阀的优点.采用空气-水体系,在直径为600mm的塔内,对双层导向浮阀塔板的流体力学与传质性能进行了测试,并与F1浮阀塔板进行了对比实验.结果表明,双层导向浮阀塔板具有操作弹性大、压降低、雾沫夹带和漏液小以及传质效率高等特点,综合性能优于F1浮阀塔板.     

双阀重波纹导向浮阀塔板的流体力学性能

采用空气-水系统,在直径1 000 mm圆形塔内对3种不同配比的双阀重波纹导向浮阀塔板流体力学性能进行了实验研究。在开孔率15.25%,堰高30 mm,板间距600 mm,3种液流强度下,测定了不同配比的双阀重波纹导向浮阀塔板干板压降、湿板压降、雾沫夹带率和漏液率等流体力学性能参数,并与单阀重波纹导向浮阀塔板进行了相互对比。实验表明:双阀重波纹导向浮阀塔板能够有效地降低雾沫夹带以及漏液,尤其在液流强度较小的时候更加明显,但同时会造成压降升高。其中,配比为26.56%的双阀重波纹导向浮阀塔板在压降增加较小时能够大幅提高雾沫夹带性能,综合性能优越,具有一定工业使用价值。其压降、雾沫夹带率、漏液率的关联公式通过实验数据拟合得出。     

两种泡罩塔板的流体力学性能研究

应用空气-水系统,在1 000 mm× 400 mm的有机玻璃塔中,测定不同结构的两种泡罩塔板的压降、雾沫夹带、漏液等流体力学性能,对实验测得的结果进行关联,得到了计算泡罩塔板各项流体力学性能的关联式,为今后的设计及应用提供依据.实验结果表明:在正常操作范围内,Ⅱ型泡罩塔板的压降、漏液点、雾沫夹带随板孔动能因子(F0)...     

Sapindaceae,cyanolipids, and bugs

Scentless plant bugs (Heteroptera: Rhopalidae) are so named because adults of the Serinethinae have vestigial metathoracic scent glands. Serinethines are seed predators of Sapindales, especially Sapindaceae that produce toxic cyanolipids. In two serinethine species whose ranges extend into the southern United States,Jadera haematoloma andJ. sanguinolenta, sequestration of host cyanolipids as glucosides renders these gregarious, aposematic insects unpalatable to a variety of predators. The blood glucoside profile and cyanogenesis ofJadera varies depending on the cyanolipid chemistry of hosts, and adults and larvae fed golden rain tree seeds (Koelreuteria paniculata) excrete the volatile lactone, 4-methyl-2(5H)-furanone, to which they are attracted.Jadera fed balloon vine seeds (Cardiospermum spp.) do not excrete the attractive lactone. Loss of the usual heteropteran defensive glands in serinethines may have coevolved with host specificity on toxic plants, and the orientation ofJadera to a volatile excretory product could be an adaptive response to save time.Mention of a commercial product does not consititute an endorsement by the USDA.     

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.     

Many Drugs of Abuse May Be Acutely Transformed to Dopamine,Norepinephrine and Epinephrine In Vivo

It is well established that a wide range of drugs of abuse acutely boost the signaling of the sympathetic nervous system and the hypothalamic–pituitary–adrenal (HPA) axis, where norepinephrine and epinephrine are major output molecules. This stimulatory effect is accompanied by such symptoms as elevated heart rate and blood pressure, more rapid breathing, increased body temperature and sweating, and pupillary dilation, as well as the intoxicating or euphoric subjective properties of the drug. While many drugs of abuse are thought to achieve their intoxicating effects by modulating the monoaminergic neurotransmitter systems (i.e., serotonin, norepinephrine, dopamine) by binding to these receptors or otherwise affecting their synaptic signaling, this paper puts forth the hypothesis that many of these drugs are actually acutely converted to catecholamines (dopamine, norepinephrine, epinephrine) in vivo, in addition to transformation to their known metabolites. In this manner, a range of stimulants, opioids, and psychedelics (as well as alcohol) may partially achieve their intoxicating properties, as well as side effects, due to this putative transformation to catecholamines. If this hypothesis is correct, it would alter our understanding of the basic biosynthetic pathways for generating these important signaling molecules, while also modifying our view of the neural substrates underlying substance abuse and dependence, including psychological stress-induced relapse. Importantly, there is a direct way to test the overarching hypothesis: administer (either centrally or peripherally) stable isotope versions of these drugs to model organisms such as rodents (or even to humans) and then use liquid chromatography-mass spectrometry to determine if the labeled drug is converted to labeled catecholamines in brain, blood plasma, or urine samples.     

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.     

2008～2009年世界塑料工业进展

收集了2008年7月～2009年6月世界塑料工业的相关资料,介绍了2008～2009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、环氧树脂、不饱和聚酯树脂)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。