多相管流蜡沉积预测模型研究进展

蜡沉积是含蜡原油及其乳状液管输过程中的常见问题,深入研究蜡沉积问题对保障管道安全经济运行具有重要意义。综述了国内外关于多相流蜡沉积预测模型方面的研究成果,提出了多相管流蜡沉积预测模型研究存在的问题及建议。     

基于OLGA软件的油井结蜡预测模拟研究

油井的结蜡不仅限制着油井的开采速度同时也限制着原油的采收率,在结蜡严重时还会造成油气井的停产。为研究井筒中的蜡沉积规律并得到蜡沉积的敏感参数,利用多相流瞬态模拟软件（OLGA）对井筒中的蜡沉积进行了模拟。研究表明：Matzain模型对井筒的结蜡模拟较为准确,结蜡最厚点在井口附近,结蜡厚度随井深的增加而减少,并对蜡沉积影响因素进行了敏感性分析。     

高含蜡原油管道蜡沉积研究综述

我国原油具有高含蜡的特点,长时间以来,蜡沉积现象一直是我们亟待解决的问题。在总结传统蜡沉积机理的基础上,对近年来逐渐获得认可的剪切弥散和老化机理进行了综述。详细介绍了目前造成蜡沉积的主要影响因素;对具有代表性的动力学模型、热力学模型及计算机训练模型进行了分析对比,并对不同模型近年来最新的研究进展进行介绍;最后对未来蜡沉积的研究方向进行了展望。     

基于灰色模型的原油管道蜡沉积速率预测

基于灰色模型理论和建模思想,GM(0,N)模型可计算多个影响因素间相互作用的拟合和预测结果,建立GM(0,5)模型并与黄启玉模型进行误差对比分析,对原油管道蜡沉积速率进行预测.拟合出GM(0,5)模型蜡沉积速率平均相对误差为0.8855％,预测出GM(0,5)模型蜡沉积速率平均相对误差为15.0369％,精度都远优于黄...     

保温原油管道蜡沉积研究综述

我国生产的原油多数为含蜡原油,目前我国的部分原油管道采用保温层保温,这类输油管道的清蜡周期是在不保温输油管道运行中由经验得来的,因此较大管径的保温输油管道清蜡周期如何确定尚需研究。通过综合分析各类文献中研究不保温原油管道蜡沉积所采用的思路与方法,提出保温原油管道蜡沉积研究的方向。     

含蜡原油蜡沉积特性与清蜡周期研究

管道清管作为减小含蜡原油管输安全隐患的主要措施,一直是工程安全研究的重要方面。对原油蜡沉积机理的分析,明确了蜡沉积过程中的主要影响因素,并对个因素的影响效果进行了评价,描述了几种不同清蜡方法的作用效果,研究了含蜡原油管道清蜡周期的影响因素,为管道清管周期的确定提供理论支持。     

原油管道蜡沉积速率预测模型研究

准确地预测原油管道蜡沉积速率能够有效确定清管周期，以保证原油管道安全运行。针对BP神经网络(BPNN)模型学习效率低、对初始权重敏感且容易陷入局部最优状态等缺点，采用改进的麻雀搜索算法(ISSA)来优化BPNN的初始权值和阈值，建立ISSA-BPNN蜡沉积速率预测模型。以华池作业区38组蜡沉积实验数据为研究对象，使用MATLAB软件搭建预测模型并进行预测，同时与BPNN模型、遗传算法优化的BPNN模型(GA-BPNN)、粒子群优化算法优化的BPNN模型(PSO-BPNN)以及SSA-BPNN模型进行对比分析。结果表明：ISSA-BPNN模型预测蜡沉积速率的平均相对误差为1.353 1%,决定系数R²为0.994 8,均优于BPNN、GA-BPNN、PSO-BPNN和SSA-BPNN模型的预测结果，证明了ISSA-BPNN模型作为预测管道蜡沉积速率工具的准确性和可行性。     

环道法对蜡沉积规律实验研究

环道法能够测量原油温度、原油与沉积面之间的温差、冷却速率、时间、剪切速率、流量等因素对含蜡原油管道蜡沉积规律的影响,测量的因素较全面;且环道法比其他蜡沉积实验装置更接近实际含蜡原油管道。在一定的工况下,研究了使用环道法实验装置的蜡沉积实验。通过对油温、壁温和流量这3个影响蜡沉积的主要因素的控制,得出了不同工况下管道的蜡沉积规律。     

含蜡原油管道清管周期优化及影响因素分析

论述了含蜡原油管道清管周期优化及影响因素,建立了油品管道运输成本的函数。含蜡原油在管道运输的过程中,管道内的蜡沉积是一个沉积与剥离同时存在的动态过程。当原油输量、环境温度与出站温度逐渐升高时,管道内原油流速增大,蜡沉积速率降低。选择合适的清管周期,使得管道运行成本最低,要在增大清管周期的同时保证其运输的燃料费用及动力费用不增加。     

含水率对原油集输管道结蜡影响分析

原油输送过程中由于管道沿线温度逐渐降低通常会在管道中结蜡,严重影响原油的正常输送。本文在分析原油集输管道石蜡沉积机理的基础上,利用沉积倾向系数法建立原油集输管道石蜡沉积模型,具体分析含水率对原油集输管道结蜡的影响,分析发现含水率对原油集输管道结蜡影响较大,其中在转向点附近时集输管道的结蜡率最高,在进行集输管道工程设计应尽量避免。     

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.     

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。     

Inorganic/organic nanocomposite coatings: The next step in coating performance

Inorganic/organic hybrid materials have considerable promise and are beginning to become a major area of research for many coating usages, including abrasion and corrosion resistance. Our primary approach is to prepare the inorganic phase in situ within the film formation process of the organic phase. The inorganic phase is introduced via sol-gel chemistry into a thermosetting organic phase. By this method, the size, periodicity, spatial positioning, and density of the inorganic phase can be controlled. An important aspect of the inorganic/organic hybrid materials is the coupling agent. The initial task of the coupling agent is to provide uniform mixing of the oligomeric organic phase with the sol-gel precursors, which are otherwise immiscible. UV-curable inorganic/organic hybrid systems have the advantages of a rapid cure and the ability to be used on heat sensitive substrates such as molded plastics. Also, it is possible to have better control of the growth of the inorganic phase using UV curing. It is our ultimate goal to completely separate the curing of inorganic and organic phases to gain complete control over the morphology, and hence optimization of “all” the coating properties. Thus far, it has been found that concomitant UV curing of the inorganic and organic phases using titanium sol-gel precursors afforded nanocomposite coatings which completely block the substrate from UV light while maintaining a transparent to visible light. Also, it has been found that the morphology of the inorganic phase is highly dependent on the concentration and reactivity of the coupling agent. Presented at the 82nd Annual Meeting of the Federation of Societies for Coatings Technology, October 27–29, 2004, in Chicago, IL.