基于GIS技术的大连旅顺口区地形起伏度测算研究

依据地形起伏度研究的理论和方法,充分运用地理信息系统软件的分析功能和制图技术,以1∶50000DEM数据为基础,利用0.01km2的动态格网以街道为评价单元进行空间信息的处理和分析,计算大连旅顺口区的地形起伏度,制成地形起伏度专题地图,划分相应起伏区,分析得出旅顺口区局部地区地形起伏度较大,起伏度指数以中低值为主,并测算出各街道实际用地情况,为本区域经济发展和城市建设提供参考,也为区域制定科学的发展规划提供依据.     

地势起伏度对三峡库区人口及经济发展水平的影响

在1[DK]∶10万三峡库区DEM的基础上,采用窗口分析等方法提取了地形起伏度,利用均值变点分析方法确定三峡库区地势起伏度的最佳统计单元是015 km2。首次绘制了基于最佳统计单元的三峡库区地势分布图,确定地形起伏度是影响三峡库区人口分布和经济发展的重要因素之一。在系统分析了三峡库区地形起伏度的分布规律基础上,选择城镇化率、农村居民恩格尔系数、经济密度、人口密度等指标,定量揭示地形起伏度对人口和经济发展的影响。结果显示三峡库区的地形总体以起伏山地为主。地形起伏度与人口密度、经济密度呈极显著的负相关,地势起伏度大的区域,人口密度较小,经济发展相对滞后,农村居民生活相对贫困。地势起伏度小的区域,人口密度较大,经济相对发达。这对认知山区人口和经济的空间格局,将三峡库区资源开发利用以及产业布局在适度的地势起伏度范围,对于有效进行三峡库区资源开发、促进区域经济效益最大化具有重要的参考价值     

A survey of flaws near welds detected by side angle ultrasound examination of anhydrous ammonia nurse tanks

A sample of 532 anhydrous ammonia nurse tanks with manufacture dates ranging from the 1950’s to 2011 were examined during 2012 by side angle ultrasound to measure the locations, sizes, and orientations of flaw indications. The indications were most frequently located on the head side of the head-to-shell welds and oriented perpendicular to the weld line in the welds’ heat affected zones. On average newer tanks had more indications than older tanks. Tanks that had been given a post-weld stress relief anneal had markedly fewer indications.     

Pressure and temperature increase of LPG in a thermally coated pressure vessel exposed to fire: Experimental and model results

Damage caused by incidents with transport tanks with compressed liquified gas is amongst the most extreme that can be encountered with transport vessels. This is particularly the case with the Boiling Liquid Expanding Vapor Explosion (BLEVE), which may occur if such a tank is exposed to fire for a prolonged period. Therefore, the local Dutch LPG transport sector adopted a thermally insulating tank coating as a ‘standard outfit’ for their tank trailers, with the aim to delay a BLEVE for a sufficiently long period for emergency services to take appropriate measures and for people near the accident location to be evacuated. On a European scale however, no consensus has been reached on the cost-benefit of such measures.With the current drive towards “greener” and renewable energy sources, this issue has regained attention with alternative fuels such as LNG, CNG and Hydrogen and a need was felt for (better) theoretical models and experimental data concerning the behavior of transport tanks carrying these substances.In this paper a new tank thermal (equilibrium) model is described to predict pressure and temperature behavior of a multi layered, thermally insulated tank containing a compressed liquified gas exposed to heat. Results are compared with data of three bonfire experiments, in which 3 m³ tanks, filled for ca. 50% with LPG were exposed to fire. A good match between modelled and experimental pressure and temperature evolution in time could be obtained using a constant value for the thermal conductivity of the insulation layer. The modelling showed that the thermal insulation value is crucial for an accurate prediction of these parameters as well as the opening time for a pressure safety valve. As relevant temperatures may cover a very wide range (from cryogenic in LNG-tanks to over 1000 °C in a fire) knowledge of the thermal (and physical) behavior of the insulating layer over a large temperature range is essential.The same holds for the behavior of the PRV when subjected to fire. Extreme temperatures may also lead to deviating behavior from what is expected based on the initial settings.     

火灾场景中细水雾幕对玻璃保护效果实验研究

在火灾环境中,玻璃极易受到过量热流的影响而发生破裂,从而增加火灾房间的通风,导致火势急剧增长,甚至跨区域蔓延。研究防止玻璃在火灾条件下破裂与脱落技术手段对火灾防控具有重要意义。基于此,提出了一种采用细水雾幕阻隔火焰热辐射保护玻璃的方法。实验通过改变细水雾幕工作压力及其在火灾不同阶段的启动,并与传统水膜法进行对比,研究各工况下的保护效果。结果发现火源与保护装置同时启动,细水雾幕与水膜都可以将玻璃首次破裂时间延长。流量为0.38 L/min时,在细水雾幕保护下玻璃首次破裂时间比水膜保护下延长361 s。细水雾幕工作压力越大,保护效果越好,但当压力超过1.0 MPa持续提高细水雾幕压力,保护效果变化不明显。当延迟到玻璃表面温度达到90℃时,启动这两种保护装置,细水雾幕对窗玻璃保护效果不受影响,但水膜法玻璃首次破裂时间会缩短。     

资源型重工业城市生态承载力评价

从城市生态承载力的三类变量之间的关系出发,构建城市生态承载力评价模型;并以资源型重工业城市抚顺市2000～2009年数据为基础,分析了该市的生态压力参数和生态弹性力参数的变化情况,评价了抚顺市的生态承载力水平。结果表明:抚顺市生态承载力变化分为3个阶段,平稳期(2000～2002年)、起伏期(2002～2007年)和递增期(2007～2009年);生态承载力水平由2000年的-0.311增长到2009年的-0.017,抚顺市一直处于重载状态,属于高耗损型,强不可持续发展模式,但有趋于可持续发展的趋势。     

论国际救灾法中的效率原则

在国际救灾过程中,抢救和保护生命、健康、财产、环境的紧迫需要使救援效率成为国际救灾中的首要追求。这一要求必须在救灾法中得到体现。效率原则就是要求重大灾害发生后,国际社会应当以最快的速度提供国际援助,而受灾国则应当尽快地作出救灾响应,在国际救灾人员的签证、工作许可,资金、物资、设备等的建立账户、通关、运输、储存、分发、等...     

掘进面多级气相压裂卸压抽采防突研究*

为解决煤层赋存条件复杂、煤体渗透率低、部分区域突出易发性高等问题,提出运用多级气相压裂的方案在阳泉矿区新元矿31004工作面辅助回风巷与进风巷进行压裂试验,以考察其卸压增透效果;在试验巷道的不同区段实施单孔压裂和双孔压裂,并采用“压裂抽采”和“压后即掘”2种工作循环方式进行试验;基于对多项抽采参数的实测结果,从多角度评价多级气相压裂效果。结果表明:多级气相压裂具有明显的重启裂缝与扩张裂缝作用,能够有效改善煤体的渗透性和瓦斯抽采条件;通过对比单孔压裂与双孔压裂效果,并结合现场监测数据发现,双孔多级压裂的效果明显优于单孔多级压裂,双孔多级压裂钻孔作业难度低,且作业后瓦斯更易抽采;观测不同的工作循环方式未见明显差距,但“压后即掘”的工作效率明显更高。多级气相压裂的成功实施,对该技术在低渗矿区的防突消突与瓦斯抽采工作中的应用具有重要指导意义。     

基于直觉模糊距离法的堰塞湖减灾方案选优

针对堰塞湖减灾群决策信息的不确定性与模糊性,为解决不完全信息条件下属性指标及专家之间存在的相互关联群决策问题,综合运用直觉模糊集理论、海明距离原理和熵权理论,将直觉模糊距离群决策方法运用到堰塞湖减灾决策过程中。工程实例研究表明,运用直觉模糊距离法决策出的最优方案具有较高的区分度和敏感性,增强了决策的客观性、科学性,能为堰塞湖减灾决策提供更为可靠的依据,具有较强的实用价值。     

The dynamic response of pressure relief valves in vapor or gas service,part I: Mathematical model

In order to prevent unstable operation, or “chatter”, of a pressure relief the API guidelines recommend limiting the irreversible pressure loss in the inlet line to a pressure relief valve to no more than 3% of the valve set pressure. This criterion is based on steady-state operating conditions and a typical blow-down pressure for the valve of about 7% of the set pressure. However, the stability of the valve is also influenced by other factors such as the dynamic response of the valve disk to the unsteady pressures and forces exerted by the fluid on the disk. A model for the opening lift dynamic response of a pressure relief valve in gas/vapor service is presented here which accounts for all of these effects through a set of five coupled nonlinear algebraic/differential equations. These equations are solved by a numerical method that can be implemented on a spreadsheet to predict the position of the valve disk as a function of time for given valve characteristics, operating conditions, and installation parameters. The model incorporates the influence of the various parameters on the stable/unstable nature of the disk response. An example is presented for a typical valve that illustrates the various modes of stable and unstable dynamic response that can be predicted by the model under various conditions. Two additional papers will be forthcoming: Part II – Experimental Investigation and Part III – Analysis of Data and Comparison with Model Predictions.