化学吸收法测定多级离心雾化旋转填料床有效相界面积及体积传质系数

对多级离心雾化旋转填料床的有效相界表面积及体积传质系数,用化学吸收法做了实验测量。实验结果表明：多级离心雾化旋转填料床不仅具有超低气阻,而且可产生良好的喷雾扩展相界面积的作用,体积传质系数比传统填料塔提高一个数量级,接近气液逆流型旋转填料床。多级离心雾化旋转填料床开拓了新的气液传热传质途径。     

化学吸收法测定多级离心雾化旋转填料床有效相界面积及体 …

对多级离心雾化旋转填料床的有效相界表面积及体积传质系数，用化学吸附法收了实验测量，实验结果表明：多级离心雾化填料床不仅具有超低气阻，而且可产生良好的喷雾扩展相界面积的作用，体积传质九比传统填料塔提高一个数量级，接近气流逆充型转填料床。     

新型旋转填料床强化气膜控制传质过程

转子结构为相互嵌套填料环的新型旋转填料床是基于强化气膜控制传质过程的新型高效传质设备,可适用于受气膜控制的吸收、精馏和低浓度工业气体的净化等过程。分别以化学吸收体系CO2-NaOH和物理吸收体系NH3-H2O测定了不同气量、液气比和超重力因子条件下的有效比表面积a和气相体积传质系数kya,并由此得到气相传质系数ky,对其传质性能进行研究。实验结果表明：a、kya和ky均随着气量、液气比和超重力因子的增大而增大。通过对比可知,新型旋转填料床的气相体积传质系数在相近操作条件下是文献逆流旋转填料床的2倍。并对实验数据进行了回归,拟合出了a、kya和ky分别与气相雷诺数ReG、液相韦伯数WeL和伽利略数Ga之间的关联式。     

旋转床填料内支撑对气膜控制传质过程的影响

采用（氨＋空气）－水这一典型的气膜控制传质体系，研究了旋转床（RPB）中填料内支撑对气膜控制传质过程的影响。实验结果表明：随着转速的增加，旋转率传质系数值提高；随着液量的增加，旋转床传质系数值降低。与无内支撑时情况相比，有内支撑时的传质效果变差。在40％－100％开孔率范围内，随着开孔率的增加，传质系数值缓慢升高，而内支撑在填料中安置位置对传质无明显影响。     

新型旋转填料床的气相传质特性

以CO2-NaOH体系化学吸收测定不同超重力因子、液量和气液比(体积流量比)条件下的有效传质比表面积a,在相同操作条件下,以氨-空气-水体系进行空气吹脱含氨富液测定不同超重力因子、液量和气液比条件下的气相体积传质系数kya,从而得到气相传质系数ky,对其气相传质特性进行了研究. 结果表明,a随超重力因子、液量和气液比增大而增大,kya和ky均随超重力因子和气液比增大而增大,随液量增大而减小. 通过对比可知,在相近操作条件下新型旋转填料床的气相体积传质系数比文献折流旋转填料床的提高36%. 对实验数据进行回归,拟合出a, kya和ky分别与气相雷诺数ReG、液相韦伯数WeL和伽利略数Ga之间的关联式.     

旋转填充床CFD模拟研究进展

旋转填充床（RPB）反应器凭借填料对液体的切割破碎作用，可以显著强化多相流之间的质量传递，大幅度减少反应时间。但是旋转填充床内部结构和流体力学规律极为复杂，即便使用高速摄像机也很难准确描述填料内的流动和传质规律。计算流体动力学（CFD）凭借其能够有效模拟多相流动过程中的流动和传质规律的独特优势，近年来已被许多研究人员用来模拟RPB反应器中的流动和反应特性。本文综述了近些年来学者利用CFD技术模拟旋转填充床反应器的研究进展，并着重总结了多相流模型的选取、边界条件的确定以及旋转填充床的简化方法等CFD计算中的关键部分。     

网板填料复合旋转床的传质性能

网板填料复合旋转床(RCB)是一种有别于填料床和折流床的新型旋转床,具有传质效率高和压降小的特点。以乙醇-水溶液为物系,在常压、全回流操作条件下,对同心环网板、同心环网板间径向填充鲍尔环、轴向填充鲍尔环、周向填充鲍尔环的这四种转子进行精馏实验。结果表明:网板填料复合旋转床的等板高度随气相表观动能因子和转速的增大出现最小值,在转速800 r min 1,气相表观动能因子1.3 kg0.5 m 0.5 s 1时,其值为28 mm。鲍尔环的填充有利气液传质,其不同填充方式的气相总体积传质系数由大到小的顺序为:周向填充、轴向填充、径向填充、无填充。     

新型填料结构旋转床传质特性

以CO2-NaOH溶液为工作介质,研究了填料特性、超重力因子、气体流量和液体流量等对不同填料结构旋转床传质特性的影响.结果表明:体积传质系数随液体流量、超重力因子和气体流量的增加而增大;对比六种填料结构的综合性能,不锈钢多孔波纹板和塑料多孔板填料结构较优;在相近的操作条件下,不锈钢多孔波纹板的体积传质系数比文献丝网错流旋转床高0.95～2.10倍、与逆流旋转床相当,比传统气液传质设备高1～2个数量级.对实验数据进行回归分析得出了体积传质系数的关联式,其平均误差小于10%.     

并流旋转床压降与传质特性的研究

利用水-空气系统对并流旋转床的气相压降进行了研究,并与逆流旋转床气相压降进行了对比。研究结果表明：并流较逆流旋转床的气相压降低;并流旋转床的气相压降随气体流量的增大而增大,随液体流量的增大而减小,随转速的增大明显降低;而逆流旋转床的气相压降随转速的增大明显升高。利用水吸收SO2的实验对并流旋转床的传质特性进行了研究。研究结果表明：并流旋转床填料层内各点的体积传质系数随着气体流量、液体流量和转速的增大而增大;填料层半径由70mm增大至90mm时,并流旋转床的体积传质系数迅速增大,而后并流旋转床的体积传质系数随半径的增大而减小。对并流和逆流旋转床填料层内体积传质系数进行了对比。结果表明：填料层半径由70mm增大至130mm时,并流旋转床的体积传质系数较逆流时大;当半径大于130mm后,逆流旋转床的体积传质系数大于并流旋转床的体积传质系数,且随半径增大而增大。根据研究结果,提出了降低系统压降的设想,即并流与逆流旋转床串联操作。     

旋转填料床中2种填料压降和传质特性的对比

分别以空气-水和磷酸钠溶液吸收模拟烟气中SO2为实验体系,对装填有θ环和波纹丝网填料的逆流旋转填料床压降和传质特性进行了对比研究,结果表明:在实验操作范围内,逆流旋转填料床的湿床压降随气量、超重力因子的增大而增大,受液量的影响很小;2种填料的湿床压降相差不大,且均低于750 Pa。2种填料的Kya均随喷淋密度、空床气速和超重力因子的增加而增大,当U=6 m3/(m2·h),u=0.73 m/s,β=85及更高的操作范围时,θ环填料的Kya比波纹丝填料高25%以上,说明θ环填料的传质性能明显优于波纹丝填料;最后得到装填θ环和波纹丝填料的旋转床湿床压降和体积传质系数的经验关联式。文中的研究结果对旋转填料床的设计和选型有重要意义。     

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.     

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.     

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。     

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.