Experimental research of the dynamic behavior of the natural gas suspension pipeline aerial crossing during pigging process

Suspension pipeline aerial crossings (SPAC) are mainly used to carry pipeline segments over large obstacles that are not suitable for trenchless technologies. It may suffer great vibrations and displacements during the pigging process due to the dynamic pigging loads and insufficient constraints from cables. Based on similarity criteria, an experimental scale model based on the Nujiang natural gas SPAC was designed and established. The vibration and displacement of the scale model were measured under different pigging velocities and liquid deposit volumes. The experimental results reveal that the natural gas SPAC vibrates during the pigging process, but the displacement versus time forms a U curve instead of a sinusoidal like curve. The extremum of the displacement is positively related to the pigging velocity and liquid deposit volume. In particular, the extremum increases by 0.37% with a 1% increase in the pigging velocity, while the displacement increases by 0.62% with a 1% increase in the liquid deposit volume. Under certain pigging conditions, or with damaged constraint components, the displacement extremum could be unacceptable. A low pigging velocity and a short time interval between two pigging operations are suggested to guarantee the safety of the natural gas SPACs. Besides, based on the experimental data, an empirical formula is developed to obtain the SPAC displacement-time curve with consideration of the span length, the pipeline diameter, the pigging velocity, the length and holdup of the liquid column. This formula can help to determine a suspicious displacement overrun, and to develop a data basis for choosing a safe pigging scheme of SPACs. This research provides insightful information to understand the mechanism of the SPAC's dynamic response as well as a practical tool to calculate the SPAC's displacement during the pigging process.     

提高测量悬浮物的准确性

通过一系列实验数据的对比，提出影响悬浮物测量准确性的两个因素——空气相对湿度和称量时间控制，从而提出较为可行的测量方法与步骤．     

悬浮型和流化床型纳米TiO2光催化反应器研究进展

围绕避免催化剂沉积、提高光透过率和催化剂分离3个方面的问题,综述了国内外在悬浮型和流化床型光催化反应器的工艺设计及改良方面所取得的进展,对当前应发展的悬浮型和流化床型反应体系提出了建议。     

土壤悬浮液中五氯酚钠（PCP-Na）的分析方法研究

探索了利用紫外分光光度法测定土壤悬浮液中五氯酚钠的方法。采用紫外可见分光光度计,选定在波长255．6nm处测定土壤悬浮液中五氯酚钠的含量,所得线性回归方程为Y=0．0287X＋0．0022,相关系数r=0．9999,检测限为0．016mg／L,加标回收率为93．357％～95．907％,实验结果表明此法简单、快速,准确性较高。     

蛋白回收工程中的气浮罐设计

简述了超滤废水提取菌体蛋白同时降低ＣＯＤ排放量的工艺原理及工艺过程，重点介绍了废水处理工艺生产线上的核心设备──气浮罐如何优化结构设计使之充分满足工艺要求。     

改性纳米碳管的理化性质、毒性及风险研究进展

随着纳米材料的广泛应用,在生产加工过程中,各种改性后的纳米碳管(CNTs)进入环境。充分认识改性后CNTs的理化性质是对其进行客观风险评价的重要前提。主要分析了几种常用方法改性后的CNTs的悬浮、吸附特征及其理化性质差异,综述了目前CNTs毒理学实验的研究进展,评价了其潜在风险,并提出了今后研究的方向。     

Mathematical modelling for conservation and management of gorgonians corals: youngs and olds,could they coexist?

Gorgonian corals are long-lived, slow-growing marine species dominating Mediterranean rocky bottoms. Endowed with complex morphologies they give a structure to the whole community, moreover, being efficient suspension feeders, they play a key role in plankton-benthos energy flow and CO₂${\text{CO}}_2$ storage. Thus, the structure and the development of benthic, hard bottom communities are linked to gorgonian survival. The red coral Corallium rubrum (L. 1758) is a precious gorgonian endemic to the Mediterranean Sea. Harvested and traded world-wide since ancient times red coral is a clear example of overexploited marine resource. This species is structured into self-seeding, genetically differentiated populations, some of which, living in the shallower part of the species bathymetric distribution, was recently affected by anomalous mortality events linked to global climate change. The co-occurrence of overharvesting and mass mortality could dramatically affect such populations. Demographic population models, widely applied by conservation biologists to check population viability and to project population trends over time are fundamental to foster survival of such populations matching harvesting to population growth rates. Therefore we set out a dynamic model of a genetically differentiated red coral population living in shallow waters. This population is characterised by small/young, crowded colonies and high recruitment rate. On the basis of the size–age structure determined for this population, a static life-history table, in which survival and reproduction coefficients of the different size–age classes were reported, has been set out. Demographic data were included in a non-linear, discrete, age-structured dynamic model, based on a Leslie-Lewis transition matrix. Our field data indicate that the recruits-to-larvae ratio is actually density-dependent. Such dependence, positive for low and negative for high density values, was included into the model and the effect of colonies of different size–age classes on recruits-to-larvae ratio was considered to be proportional to the number of polyps they have. We applied such model to simulate the trends of the studied population under different increases of survival and life-span. As some populations of gorgonians actually show the dominance of sparse, big/old colonies and low recruitment rate, while others are characterised by crowded, small/young colonies and high recruitment rate, we simulated the shift from the former to the latter structure increasing survival and life-span. Our results suggest that a dramatic mortality increase of bigger–older colonies (due, in the case of red coral to overfishing) could have determined the population structure we found.     

悬浮填料对干旱寒冷地区A2/O工艺脱氮过程强化研究

采用投加悬浮填料方法和高通量测序技术研究新疆干旱寒冷地区污水处理厂的硝化、反硝化速率及生物膜菌群.结果表明,环境温度与水温具有良好的相关性;悬浮填料对氨氮和NO3--N均有降解作用,平均去除率分别为75.72％和81.42％;悬浮填料填充率在20％ ～30％、曝气量在6.0 m3/h～6.5 m3/h时,总氮平均去除率...     

水中悬浮物干扰溶解氧测定结果的探讨

通过滤液和混样测定溶解氧的对比实验，探讨和分析悬浮物对溶解氧测定结果的干扰．     

悬浮液进样-火焰原子吸收光谱法测定土壤中铜

应用悬浮液进样火焰原子吸收光谱法,成功地测定了土壤中的铜。在制备土壤样品悬浮液过程中,对悬浮液的酸量、悬浮剂的浓度及土壤样品粒度的影响等均进行了试验。样品在( 105±2 )℃下烘干4h,研磨过200目筛,加入1 5g/L琼脂悬浮剂10mL和适量硝酸,使样品呈0 2mol/L硝酸悬浮液,充分混合振荡,直接上机测定。通过测定国家土壤标准参考物质,表明该法准确可靠。为进一步验证该法的适用性,又测定了实际土壤样品,且与常规法作了对比,表明两种方法的测定结果一致,而悬浮液的制备更为快速简便。