容器内液体体积的快速计算法

对于平底容器,我们能够很快地直接计算出容器的体积和容器内液面的高度。但是,对于两端呈椭圆形的容器,我们就很难计算了。这里向大家介     

压力容器大直径接管现场试压盲板的选用及设计

文章根据现行的容器标准,讨论了容器试压时容器接管封堵用封头形式及厚度计算,主要包括椭圆形封头,平盖封头、盲板法兰等封头的设计选用,并探讨了带加强肋平盖封头壁厚和加强筋数量、厚度的计算方法.该方法计算的盲板安全、经济,在中石油七建公司承建的抚顺、钦州项目得到实际应用验证,达到预期效果.     

钢制焊接常压容器圆形平盖加平行角钢加强筋的设计计算

NB/T 47003.1-2009未给出容器公称直径大于2 200mm时,平盖厚度和角钢加强筋规格的计算过程。为此,进行了圆形平盖加平行角钢加强筋的设计计算,为平盖角钢加强筋的规格选择提供依据。     

原子荧光法测定土壤中汞的前处理方法优化

本文建立了用控温深孔加热板,一次性聚丙烯平底离心管消解土壤汞的前处理方法。采用控温深孔加热板作为加热装置、一次性聚丙烯平底离心管作为容器,对土壤样品进行前处理消解,并利用原子荧光光度计确认聚丙烯平底离心管空白、方法检出限、精密度和正确度。实验室结果表明,采用控温深孔加热板作为加热装置、一次性聚丙烯平底离心管作为容器,成本低、检出限低、精密度高、准确度可靠,实验操作简便,能够快速、准确完成土壤样品中汞的检测。     

基于ANSYS的油罐罐底板厚度优化

基于油罐安全运行的重要性,以某大型油罐为研究对象,从油罐罐底板厚度对应力的影响角度进行分析,对静水压下的油罐展开理论分析,利用ANSYS软件对油罐罐底板展开有限元分析,并与理论计算结果进行比较,从而验证有限元模拟的可行性。再运用ANSYS软件来分析罐底板厚度与其应力的关系,得出罐底板厚度的最优解,这对油罐的结构优化和安全运行具有重要意义。     

带半圆管夹套真空圆筒厚度计算探析

在我国,带半圆管夹套容器的设计执行的标准是《钢制化工容器强度计算规定》(HG/T20582—2011)第3章"半圆管夹套容器的设计"。《钢制化工容器强度计算规定》中规定"容器圆筒和封头部分的名义厚度和有效厚度按照不带半圆管夹套时的同一容器,根据计算压力为正压或负压,按《钢制压力容器》(GB 150—1998)的相关章节确定"。经分析,当带半圆管夹套的圆筒为真空圆筒时,《钢制化工容器强度计算规定》中的上述规定是不合理的。而对于带半圆管夹套真空圆筒未被半圆管覆盖的部分,属于两端无支撑的外压圆筒,其厚度应按《压力容器》(GB 150—2011)有关章节中的"长圆筒"计算,然后再与按《钢制化工容器强度计算规定》中的有关公式确定出的半圆管覆盖部分的圆筒厚度进行比较,取厚度计算结果两者中的较大值作为带半圆管夹套真空圆筒的设计厚度。     

《普通碳素钢及低合金钢贮罐标准系列》出版信息及内容简介

HG5—1571～1580—85《普通碳素钢及低合金钢贮罐标准系列》已由中国标准出版社出版。该标准系列包括下列几类容器的主要结构尺寸、重量及选用说明。1.HG5—1571—85 普通碳素钢及低合金钢贮罐标准系列分类与技术条件。2.HG5—1572—85 平底平盖贮罐系列。3.HG5—1573—85 平底平顶贮罐系列。4.HG5—1574—85 平底锥顶贮罐系列5.HG5—1575—85 90°无折边锥形底。平顶贮罐系列     

压力容器设计中的厚度问题

介绍了压力容器设计中的计算厚度、设计厚度、名义厚度、有效厚度以及不包括腐蚀裕量的最小厚度之间的关系。分析了在规则设计中,卧式容器、开孔补强、外压容器(元件)这三种情况下,其计算厚度的真正涵义。选取腐蚀裕量的一般要求。以及对于设备最小厚度的一般规定。     

大型立式衬胶储罐罐底设计探讨

大型立式衬胶储罐在化工行业应用日益普及,工程造价、质量与安全要求高,因此对罐底设计提出更高的要求。分析罐底主要结构形式及其优缺点,以及衬胶储罐底板的特征,探讨其计算模型、设计方法和流程。分别以强度和刚度为设计准则计算底板厚度,然后选其较大值作为底板的有效板厚度值;底板加强梁则先以刚度为设计准则计算组合梁的总惯性矩,再初选加强梁的规格型号以确定主要几何参数,然后再校核结构强度;归纳总结上述方法的设计流程,并编写流程图。最后以φ12m×12m磷酸储罐为例,设计其罐底底板厚度和加强梁。     

平底平盖增高型硫化罐

介绍平底平盖增高型硫化罐的结构特点与应用情况。与传统硫化罐对比,在相同产能下,平底平盖增高型硫化罐的占地面积减小,操作人员减少。同车间产能情况下,不同型号39台平底平盖增高型硫化罐每年可节约蒸汽1 266 174m3,价值约250万元,降低了产品成本且提高了生产效率。     

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.