成型物料混合均匀度对型煤质量的影响

通过对型煤成型物料混合均匀度的实验研究 ,总结出检验型煤搅拌设备搅拌效果和定性判断型煤生产过程中物料混合均匀度的测试方法。     

卧式双轴搅拌床反应器混合特性研究

本文对卧式双轴气相聚合搅拌床反应器的混合特性进行了实验研究。以三氧化二铝粉体和氯化钾粉体分别为主体物料和示踪物料,用电导法考察了搅拌转速、器内物料的装料高度及通气速率对该搅拌床反应器的混合特性的影响并获得了相应的关联式。结果表明,弗鲁德数、无因次装料高度及通气速率对混合特性有明显的影响。     

基于假设检验和试验设计优化安全气囊气体发生剂的气动混合工艺

采用等离子体原子发射光谱法,测定在安全气囊气体发生剂的传统机械混合工艺与气动混合工艺中制得的特定物料的元素含量数值(响应变量,Y),以表征混合的均匀度。通过独立性检验、正态性检验(AD检验)、异常值检验、双方差检验(F检验)、双样本t检验选定了假设检验方法。试验表明,在显著性水平取0.05时,对于安全气囊气体发生剂混合工艺的混合均匀度,气动混合技术优于传统机械混合技术;采用试验设计(DOE)的方法建立并简化模型,通过统计软件响应优化器的功能对混合工序的特定物料元素含量进行测试,采用DOE试验分析的望目特性优化气动混合工艺参数。结果表明:最佳混合时间为11 min,进气压力为0.2 MPa,响应变量(Y)的95%置信区间为(22.174 3,22.803 7)。     

组合螺带桨搅拌槽内粉体的混合性能

在直径0.48 m的立式搅拌槽内研究了4种组合式螺带搅拌桨的粉体混合性能,考察了搅拌转速、粉体物料装填高度和搅拌桨型对粉体混合性能的影响,分析了径向与轴向上的粉体混合情况. 结果表明,搅拌转速是影响粉体混合的重要因素,增加搅拌转速能明显缩短混合时间,转速44.0 r/min时的混合因子π3比转速8.7及26.5 r/min时下降50%及30%以上;在搅拌桨内部附加较小的内桨使功率略有增加,但可显著缩短混合时间,转速44.0 r/min时能使π3下降50%,提高混合效率.     

高塔复合肥熔体料浆与粉体物料的喷射混合装置设想

设想一种高塔复合肥熔体料浆与粉体物料的喷射混合装置,采用喷射器和离心泵结构,与具有加热功能的混合搅拌桨结合,以适应超细粉体物料的快速混合,可望生产高质量的球形颗粒复合肥.     

基于香农熵的超细粉体填料混合均匀度的评价研究

以香农熵理论为基础,提出了一种量化表征超细粉体填料在基体中混合均匀度的方法。以高密度聚乙烯/碳酸钙(PE-HD/CaCO3)复合材料为研究对象,首先用Photoshop和Image-pro-plus对样品扫描电子显微镜照片中的颗粒和团聚体尺寸进行统计,计算出了相对香农熵和团聚系数,分别表征超细铝粉的分布混合和分散混合,然后引入混合系数对混合均匀性进行综合评价。结果表明,添加了分散剂的PE-HD/CaCO3,CaCO3混合系数较高,拉伸强度和弯曲强度较大,验证了此方法对超细粉体填料混合均匀度评价的适用性。     

粉磨方式对玄武岩作水泥混合材性能的影响

讨论了不同粉磨方式下玄武岩用作水泥混合材的性能变化。结果表明,采用球磨机时,1h左右即达到“粉磨平衡”状态;玄武岩对共同粉磨物料有显著的助磨作用;玄武岩作混合材时,可对其进行预粉磨,按一定比例混合粉磨,以充分利用玄武岩粉体的“微级研磨体”作用,优化混合材与熟料粉体群之间活性与非活性组分的搭配和组成。     

旋转流化床粉体混合机混合效果数值模拟和实验验证

为了对旋转流化床粉体混合机进行优化设计,采用CFD-DEM联合仿真的方法,对旋转流化床粉体混合机内球形颗粒的混合过程进行数值模拟,通过Lacey指数具体评价颗粒的混合效果,研究了进气管倾斜角度、进气管布置方式、进气方式对球形颗粒混合效果的影响,并进行球形颗粒混合实验验证。结果表明,进气管最合适的倾斜角度应保证气流作用区域面积恰好为底部颗粒物料区域面积的一半。进气管水平布置时能够保证很好的混合质量及较快的混合速率。脉冲及连续方式进气均能实现均匀混合,脉冲进气方式比连续进气方式耗气量更低。颗粒混合实验有很好的混合效果,与数值模拟的结果具有较高的一致性,从而获得了一种混合效果优越的结构形式,进气管倾斜角度α=35°,水平布置。     

大差异颗粒静态混合的实验研究

设计了一套混合段内安装挡板锥体内构件的实验装置,采用较大粒径差异的煤与瓷球,通过改变挡锥组数、加料比例等影响因素,对颗粒群的混合行为、混合均匀度的变化趋势与混合机理进行研究。结果表明:在混合段内设置挡板锥体是一种有效的混合方式,可以获得较好的混合均匀度;瓷球/煤的质量比5∶1加料时,混合效果最好;混合机理方面,对流、剪切、扩散共同作用于混合过程。     

销钉机筒挤出机螺槽横截面内流体流动与混合的研究

在一定简化条件下，对销钉机筒挤出机螺槽横截面内的流场及混合均化效果以及销钉位置对流场和混合均化效果的影响进行了数值与实验研究。提出了流场中某点混合均化效果、整个流场平均混合均化效果以及混合均化效果统计分布的数值计算与评价方法。数值分析结果与实验结果具有较好的一致性。结果表明，销钉对物料具有明显的强化流动与混合均化的作用：销钉愈接近于螺棱，强化混合均化的效果愈显著：有销钉结构较无销钉结构的平均混合均化效果提高2．5％-5．6％；有销钉结构随着挤出时间的增加，混合均化效果不断提高，无销钉结构随着挤出时间的增加，当混合均化效果达到一定值后则不再提高。     

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.     

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。     

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.     

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.