Application of WASP model for assessment of water quality for eutrophication control for a reservoir in the Peruvian Andes

Water quality models are important tools for facilitating assessment of the main processes occurring in an aquatic system. To this end, a water quality analysis simulation programme (WASP8) was used to assess the eutrophication process in El Pañe Reservoir. The reservoir has a useful water volume of 99.6 hm³ and is connected to six other reservoirs located in the Chili Basin of the Arequipa Region. El Pañe Reservoir, which is the basin head, has exhibited eutrophication problems since 2014, causing water treatment problems for human consumption and a high probability of cyanotoxin releases from intensive algal blooms. Accordingly, the reservoir was divided into 11 segments, ammonia, nitrate, phosphate, total phosphate, dissolved oxygen, water temperature and chlorophyll‐a being the simulated water quality parameters. The simulations were set in a steady state condition for 3 years from October 2015 to October 2018, subsequently determining aquaculture activity and benthic flux as being meaningful nutrient sources impacting the phytoplankton community. The results of the present study provide necessary evidence of the need to exhaustively quantify both sources in future research, which will aid decision makers in identifying the best management option that can help guarantee the sustainable development of the involved human activities.     

Numerical study on the spark ignition characteristics of hydrogen-air mixture using detailed chemical kinetics

Hydrogen is a promising fuel and is expected to replace hydrocarbon fuels for its significant potentials to reduce the pollutants and greenhouse gases. It is very important to investigate Minimum ignition energy (MIE) on safety standards and ignition process of hydrogen-air mixtures. Even though the formation of flame kernels in quiescent hydrogen-air mixtures has been researched numerically and experimentally, the details of ignition mechanism have never been satisfactorily explained. In this study, the spark ignition of hydrogen-air mixture is investigated by using detailed chemical kinetics and considering the heat loss to the electrode. The purpose of this study is emphasized in the effects of the energy supply procedure, the radius of the spark channel, electrode size and electrode gap distance on the MIE. In addition, the effects of mixture temperature, electrode gap distance and electrode size on relationship between the equivalence ratio and the MIE are examined.     

Impact of the Tobacco Price Support Program on tobacco control in the United States

OBJECTIVES—To evaluate the impact of the United States Tobacco Price Support Program (TPSP) on domestic cigarette consumption and the potential political impact of the TPSP on efforts to reduce smoking.
DATA SOURCES—Published studies known to the authors and a search of AGRICOLA from 1980 to 1996.
STUDY SELECTION—Studies published in a refereed journal or research reports published by an accredited university or institution.
DATA SYNTHESIS—The TPSP decreases cigarette use by increasing the price of cigarettes. The price increase resulting from the TPSP, however, is small—about one cent per pack. The resulting decrease in cigarette consumption is also very modest—an estimated 0.23%. However, the TPSP creates tobacco quota owners, who have a strong financial interest in opposing measures to reduce smoking. The TPSP also changes the political influence of tobacco farmers by keeping a large number of small farmers in tobacco production.
CONCLUSIONS—The negative impact of the TPSP (opposition to tobacco control measures) is probably greater than the positive impact of the programme (reducing smoking). Therefore, the net impact of the TPSP on tobacco control efforts is likely to be negative.


Keywords: cigarette consumption; Tobacco Price Support Program; United States     

厚壁压力容器声发射源定位精度分析

刘富君等人在论文“厚壁压力容器声发射技术声源定位误差分析”中,用实验与理论相结合的方式对厚壁压力容器定位误差进行了分析,作出了误差轨迹线。文章是在此基础上对该问题作了进一步的探讨,通过等价无穷小及忽略无穷小量等数学技巧,认为误差点近似位于同一直线上,与刘富君等人的实验数据相符,并得出了该直线的解析表达式,最后根据此直线方程提出了通过实际误差点反向移动特定距离来大幅缩小厚壁带来的误差,从而大大提高定位精度。     

催化装置低温余热利用分析

通过对某石化厂催化装置低温余热利用现状进行分析,提出了利用催化装置低温余热的3个有效方案。通过综合比选后得出：将催化装置顶循热作为2号气分装置脱丙烷塔的重沸器热源,替代原来脱丙炕塔重沸器的加热蒸汽,合理地利用了催化装置的一部分余热。剩余热量以热媒水方式供热,直接供给厂内原有热用户、新建溴化锂制冷站和厂内主要办公大楼的夏季空调使用。从而较大的减少了炼厂蒸汽的使用量,减少了全厂循环冷却水的使用,提高了炼厂能源的综舍利用率,提高了炼厂经济效益。     

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将天然气管道输送理论、灰色系统理论、最优化理论和决策支持系统理论相结合，开发研究出“天然气长输管道设计方案优选系统”(简称GPDOS)，实现了沿线地形起伏，沿线有若干进、分气点的长距离输气管道设计方案优选。章详细介绍了GPDOS设计的基本过程：概念设计、功能设计和结构设计。算例在GPDOS上的运行表明，该系统的独到之处在于：实现了天然气长输管道工艺计算和方案优选的自动化，实现了多方案计算的任意组舍；对优化投资费和运营管理费，缩短管道设计方案优选周期，快速获取输气管道沿线各段直径、壁厚和沿线压气站位置、数目、压气机型号及其组合方式以及输送压力等一系列最优参数，提高设计质量取得了明显的效果；对更新设计观念，按系统论的思想方法考虑工程设计问题起到了促进作用。     

有机化合物在超临界流体中溶解度的模拟计算

为了预测有机化合物在超临界流体中的溶解度数据，以Peng Robinson状态方程为模型，开发了一个用于计算含超临界流体相的气-液相平衡计算程序。对于已经发表的丙烷+辛烷、氢气+正己烷、SC-CO₂+柠檬精油、SC-CO₂+α_-蒎烯、SC-CO₂+葑酮等5个二元体系共计168个实验数据，用上述程序进行了检验计算，温度范围为310～377 K，压力范围为2～12 MPa。计算结果表明，选用适当的混合规则，只考虑一个二元相互作用参数就可以获得满意的计算精度：对于丙烷+辛烷系统，液相组成的计算误差最大为3.83%，气相组成最大误差0.29%；CO₂+柠檬精油系统，平均相对误差值为2.71%；CO₂+α-蒎烯系统，平均相对误差值为1.18%；CO₂+葑酮系统，平均相对误差值为1.69%。该程序可以为超临界流体过程开发和设计提供基础数据。     

模糊综合评判法优选地下储气库方案设计研究

在天然气供应与消费之间，一直存在着可靠、安全、平稳、连续供气与消费需求量季节、昼夜、小时不均衡性的固有矛盾。随着天然气国际贸易的发展和边远气田的开发,以及输气的平均运距和运时大大增加，使这一矛盾进一步加剧。而地下储气库则能够解决这一矛盾。由于天然气地下储气库建库方案的确定具有多目标性，因此建设天然气地下储气库前期必须对储气库的建库方案进行充分的技术和工程论证。为此，在研究天然气地下储气库建设方案设计部署原则的基础上，确定了8项评价因素：地层注气末压力、地层采气末压力、工作气规模、垫层气比例、工作井数、单井注气能力、单井采气能力和单位注采气成本。采用模糊数学中的综合评判方法，对地下储气库的建库方案进行了综合评判，应用最大隶属度原则确定出方案集中的最优方案。通过计算实例，验证了模糊综合评判法优选地下储气库方案的可行性，得到了某地下储气库的最优建设方案。     

鄂尔多斯盆地中东部奥陶系盐下深层储层特征及主控因素

鄂尔多斯盆地奥陶系盐下深层白云岩储层近年来取得较好的勘探效果,具有一定勘探前景。综合运用岩心观察、铸体薄片、扫描电镜、物性分析、压汞等资料,对盆地中东部奥陶系盐下深层马家沟组马三段、马四段储层特征及其发育的主控因素展开研究。结果表明：马三段储层以海退蒸发环境的含膏云岩为主,马四段储层以海侵环境的灰质云岩、粉—细晶云岩为主;马四段、马三段主要储集空间类型分别为溶孔（溶洞）、晶间孔、晶间溶孔、微裂隙;微裂隙、膏模孔、溶孔和粒间孔;孔隙结构复杂,毛管压力曲线形态可划分为溶孔型、晶间（溶）孔型、微裂隙型和微孔型4种类型;现有资料显示马三段—马四段平均孔隙度分别为2.1%和2.3%,平均渗透率分别为0.19×10^-3 μm²和0.22×10^-3 μm²。中央古隆起、乌审旗—靖边次级古隆起以及神木—子洲低隆带控制了马三段—马四段沉积相带及有利岩相分布;沉积微相控制岩石原始沉积组构,一定程度影响储层物性,砂屑云岩、晶粒云岩及膏质云岩的储层物性通常相对较好;此外,成岩作用也是控制盐下储层发育的关键因素,多种成因机制下的白云化作用是晶间孔形成的主要方式,表生成岩环境及埋藏成岩环境下的溶蚀作用控制了次生孔隙的发育;燕山期构造活动对储层微裂隙的发育起关键作用,显著改善了储层渗透性。总之,构造背景、岩石组构、成岩作用以及裂缝作用决定了盐下深层储层的储集性能,是优质储层形成的主控因素。     

天然气管线内腐蚀速度的逐步回归预测

为了更深入地探索天然气管线中所输介质与内腐蚀之间的关系,利用实验获得在气相或液相中Ｈ２Ｓ、ＣＯ２、缓蚀剂浓度与其所导致的内腐蚀速度值,采用数理统计的方法,确定Ｈ２Ｓ、ＣＯ２、缓蚀剂与内腐蚀速度之间的最佳的逐步回归方程,以达到预测内腐蚀速度的目的。所有逐步顺归过程及预测由编写的程序系统来完成。