管道

At the same time, combining with the actual condition of delivery pipeline of our country and some prevalent leak detection and location methods, this paper raised a method, which is based on wavelet analysis and negative- pressure-wave to detect and locate the leakage. Jobs in the paper are as follows:As affected by gas density, pressure, specific heat and pipe material, the velocity of negative-pressure-wave improved depending on the energy conservation. At one time, taking the affection of velocity of gas flow, the location formula was modified in some degree.When locating the leaks with location formula, the iterative approach algorithm was adopted as a new method to increase the location accuracy level of system.Multi-scale decomposition and reconstruction of wavelet transform is utilized to filter the noise of negative-pressure-wave, which was brought by leakage. With the capacity to detect the signal singularity fast and accurately, wavelet transform was used to catch the break point of pressure signal. The work improved the accuracy of At in location formula, accordingly improved the location accuracy.Wavelet is a suitable tool for signal analysis. The distinct character is that the mother-wavelet is of optional. That means choosing different mother-wavelet will get different analysis result. So we studied how to choose mother-wavelet and its scale for signal singularity detection. The method is to choose a wavelet by regularities of the wavelet and the signal.Finally, a plan, which bases on SCADA system for inspection and detection of natural gas leakage, is proposed in the article.

其中，主要进行了以下几方面的工作：针对泄漏产生的负压波在管道中的传播速度受媒介的密度、压力、比热及材质等因素的影响，而非声波在空气中传播的速度，本文利用能量守恒原理，对其进行了修正；考虑到管内气体流速对压力波速的影响，对原始的负压波定位公式进行了一定程度的改进，并在利用定位公式进行泄漏点定位时采用逐步迭代逼近算法，提高了系统的定位精度；利用小波变换的多分辨率分解和重构技术，对采集到的管道发生泄漏时产生的负压波信号进行了降噪处理；并利用小波变换技术对信号奇异点的快速、准确的识别能力，对经上述消噪后的负压波信号进行了奇异点捕捉，精确捕捉的结果提高了定位公式中上下游站点采集到的负压波奇异点的时间差△t的精度，从而进一步提高了定位的精度；考虑到小波变换是一种基波可变的信号分析工具，也就是说，不同的小波基波对信号分析的结果将有很大差别，这势必影响最终的处理结果，因此，我们又对比分析了本课题中小波基及尺度的选择问题，依据规则性系数相似性原理对母小波的选择进行了探索性研究；最后，还提出了基于SCADA的泄漏检测与定位系统的软件开发构想及系统的嵌入方案。

Every time the residents brush their teeth,millions of gallons of water must be drawn from the Catskills and the hills of Westchester.

地下的电话线、输电线、蒸汽管道、煤气管道和下水道系统是把这块地方交给神和象鼻虫来支配的充足理由。

You should also caulk all windows, doors, and pipes to prevent air leaks in or out, use weather stripping around windows, doors and pipes as well.

你也应该嵌缝膏所有门窗，管道，以防止空气泄漏或流出，利用天气剥离前后门窗和管道等。

The visionary Swiss dye-works team had proven talent with the invention of their centrifugally cast cylinders and very soon recognized that the advantages the material and its special production method brought about were suitable also in a completely different field of application: for piping.

瑞士染色工厂团队想象力丰富，发明了离心浇铸圆筒，并很快认识到这种材料的优越性。这种特殊生产方法同样适于另一个完全不同应用领域：管道应用领域。精确地说，应是50年前，第一次将圆筒作为管道来运输水。

Based on the previous MHD duct flow experiments, the law of mass conservation, the law of charge conservation and the Lorentz force as well as the principle of equivalent circuit, a simplified theoretical method to analysis MHD effect of duct with FCI is developed.

基于先前的普通管道中的MHD效应的实验结果和质量守恒定律（或液态流体不可压缩原理）、洛仑磁力定律和电荷守恒定律，再利用有源网络等效方法，发展出一种简化而有效的分析带通道插件管道的磁流体动力学效应的方法。

A pipeline shutdown shall occur automatically if any valve in the pipeline flow path is closed.

管道关机，应自动如果发生任何阀在管道流路是封闭。

The pipe operation has failed because the other end of the pipe has been closed.

因已关闭管道操作的另一端而使管道操作失败。

Reporter arrived on the scene that the Company has been damaged pipe valve repair personnel Plug Valves closed excavation are being damaged pipe repair.

记者赶到现场看到，煤气公司抢修人员已将受损管道阀门关闭，正在对受损管道进行开挖抢修。

The tenants have reflected this situation to the heating sector, staff Safety valves emergency examination revealed that 4 shortlisted cell thermal wells for heating pipe valve was closed, the switch handle is cut the same time, the well of the heating return pipe valve doors were also damaged, apparently caused by man-made.

住户们将这一情况反映给供暖部门，工作人员紧急检查发现，小区热力井里这4栋楼的暖气管道阀门被人关上后，开关手柄被砸断，同时井内的暖气回水管道阀门也遭到破坏，明显是人为所致。

Pipe Insulation : winter outdoor temperature is low, according to authorities, started heating cable, pipe insulation pictorial display brightened.prevent freezing pipes, according to bond closed heating cable pipe insulation

管道保温：冬天室外气温较低时，可按键，启动电热带，同时显示屏管道保温图案点亮，防止水管冻裂，再按键，则关闭电热带

The labia have now been sutured together almost completely.The drains and the Foley catheter come out at the top.

此刻阴唇已经几乎完全的缝在一起了，排除多余淤血体液的管子和Foley导管从顶端冒出来。

To get the business done, I suggest we split the difference in price.

为了做成这笔生意，我建议我们在价格上大家各让一半。