The authors thank the staff of the WVU Center for Alternative Fuels, Engines, and Emissions, including Mr. Zachary Luzader and Mr. Christopher Rowe. The author's thank the Environmental Defense Fund, the WVU Research Corporation, and the George Berry Foundation for funding the research programs that provided field data and a variety of test conditions under which to use the developed FFS.

注:农民田间学校已设计在充分考虑安全，以消除或减少甲烷或天然气源点火的可能性。天然气是在体积浓度5％至15％的环境条件下易燃。该系统将被测试和证明，以满足安全要求。修改或篡改系统造成严重的伤害。 1. MAF的校准注:MAF需要对标准的国家与技术研究所（NIST）可溯源层流元件（LFE）定期校准。使用程序中的校准工具来完成MAF校准与已知LFE。该计划将收集来自压力传感器，湿度传感器所必需的所有数据，并MAF创建一个新的校准。建议在11点校正完成。如果校准年龄超过一个月，一次新的校准应完成。老的校准可以查看和用过的。 <ol><li>选择一个适当大小的LFE确保流量范围是LFE的较低流量范围的大于25％。 </li><li>的MAF连接到流动长凳确保入口到MAF是任何限制或扩展的下游的至少10的直径。 </li><li>组合绝对/差压计连接到流动板凳LFE的压差端口。 <ol><li>确保压力差换能器的校准中。传感器的高压侧端口连接到上游LFE端口。传感器的低侧端口连接到LFE的下游端口。 </li><li>确保合并差分/绝对压力计的绝对压力换能器是校准内，并通过一个"三通"嵌合到差动压力传感器的高侧端口连接。 </li></ol></li><li>一个K型热电偶连接至数据获取单元（DAQ）。 </li><li>确保露点测量设备在校准和连接到所述数据采集和空气流。 </li><li>确保农林部和流量板凳信号是可以接受的（0-5伏）和使用该软件校准屏幕开始MAF校准。 </li><li>设定在11个不同的流速穿过MAF的预期范围和LFE的可接受的范围内的流动。通过点击收集校准数据按钮收集在1赫兹的最小速率的最小每个流条件数据的30秒的。 请注意:确保MAF校准跨越用于校准的LFE的最小流率的至少25％。不超过LFE的最大流速，如果较大的流速要被校准，使用较大的LFE。 </li><li>通过单击过程校准数据按钮运行校准软件，并选择曲线拟合能够产生最少的总误差不超过±2％的单点错误。 </li></ol> 2.温室气体分析仪的校准注:温室气体肛门yzer应该在内部每年由第三方进行校准。用户可以使用软件中的校准工具来完成外部校准或检定。校准用已知浓度的瓶装气体。的气体通过气体分配器和退出到淹没探针与氮气混合。分析器引入口在已知流速样品并记录该值。建议在11点校准来在感兴趣的范围内完成。该程序会自动调整为气分中的气体浓度和粘度。 <ol><li>在此之前现场测试，如果执行外部检定或校准必要的（以前的校准超过一个月以上）。 </li><li>功率上验证/校准前15分钟和连接验证"三通"嵌合到传感器的入口温室气体传感器。 </li><li>选择EPA协议或NIST溯源的气体，以验证和使用超高纯度的氮气（UHPN）作为平衡气体。 </li><li>验证气体（甲烷）连接到使用监管机构批准的校准的气体分压的组件端口（CGA 580 UPHN，CGA 350甲烷）。气体分配器的出口连接到步骤2.2的"三通"。 </li><li>通过调节调节器旋钮表压（psig） - 设置组分气体，出口压力约23磅每平方英寸。平衡气，出口压力设置为约19 PSIG。设置气体分流到至少两次与气体分隔样品泵的内部流率的流率，流量控制旋钮（电流样品泵以每分钟两个标准升（SLPM），以使气体分配器的出口进行操作应在4 SLPM进行设置）。 注:充分与气体混合物淹没试样探头以确保适当的验证。使用辅助转子流量计（如果可用），以确保合拍2.3洪水探头&#39;三通&#39;的净正流。 </li><li>单击开始校准和输入b该成分气体（用ppm）的ottle浓度。使用气体分配器来选择成分气体的范围从零至100％（11总点）。收集数据在气分完成线性化的每个设置最少有30秒。 </li><li>选择一个新的外部校准是否应用。 注意:如果所述验证的气体瓶浓度的不确定性（通常为1-2％）内通过，那么一个新的外部校准不需要被创建。 </li><li>重复为单个或多个点验证/甲烷的校准，二氧化碳，或水蒸汽的现有步骤。 </li></ol> 3.全系统恢复测试注意:一个完整​​的系统恢复测试完成，以确保FFS复苏，准确地报告校准气体的已知体积。 <ol><li>电源的FFS，确保温室气体传感器已经在至少15分钟。选择要测试恢复气体 - 甲烷。 </li><li>煤气瓶连接到一个适当的调节器，并设置出口压力约20 PSIG。 </li><li>供应管线向气体瓶调节器和所述入口连接到一个校准质量流量控制器（MFC）。在MFC的出口连接到采样软管的入口。选择在数据采集软件中的气体恢复验证选项卡，并连接了MFC的DAQ串行连接。 </li><li>点击开始气体回收测试并记录背景数据为至少30秒，气体的已知流率可以在这个时候输入。 </li><li>回收的气体的流速设置为基于预期的或以前的值（20 SLPM或30 SLPM）的平均泄漏大小。开始流动的恢复气体，并让系统稳定，持续30秒。 </li><li>稳定后，点击记录，并允许节目录制泄漏验证数据，持续30秒。 注意:当采样软件将创建示出的公知的气体流量和所回收的气体流量之间的误差的报告的完成。一个的±4.4％的误差是可以接受的（系统的相对测量不确定度），但其定位的恢复误差为±2％。 </li><li>重复气体回收试验至少三次，并确保所有的错误都在可接受​​的范围之内。 </li><li>检查任何故障的系统，如果误差超过±4.4％。仔细检查所有连接​​，流速，修正错误，并重复步骤3.2至3.6。 注意:故障可包括供应线路可能不具有被插入到FFS采样软管或连接均上样接头松动。如果以前未完成时（在一个月内）一个新的MAF校准或传感器验证可能是必要的。 </li></ol> 4.检漏审计注:执行现场清点，以确定无组织排放的每一个潜在来源。该清单将包括由源源组细分（阀门，法兰，泵/压缩机，通风口等 ）（压缩机建筑的数量，存储农场，Vehicle加油架等 ）并联或串联的量化泄漏可能发生泄漏检测审核。手持式甲烷检测仪或光学气体成像摄像头，可以用来检查是否有泄漏的部件。当泄漏确定的记录的说明，浓度和拍摄图像。大关后定量泄漏或此时量化泄漏。 <ol><li>创建程序中的新的清单文件。在网站上输入的详细信息和库存报告的目的（名称，站点类型等 ）。日期，时间戳记，和GPS位置被自动填充。 </li><li>零对环境空气的手持式甲烷测定器才能使用。利用具有取样探头手持式甲烷检测仪检查是无组织排放存在访问的所有潜在的接口。定位探针样品入口垂直于表面，以尽量减少稀释。 注意:手持式单元的灵敏度为5ppm以上背景时zeroeD于环境空气中。 <ol><li>文档无法访问任何来源或聚合源。 注意:不可访问来源可以包括:排气管是超出了安全的访问高度由网站经营者确定。凝集源可以包括连接到歧管或由服务框包围的多个气动阀。如果源或多个源可以用外壳进行审查，作为一个整体，聚集来源。 </li><li>聚合多个源使用的外壳具有至少一个入口和一个出口。文档外壳的周界内的所有资源。标签源作为总样本，并使用第5条定量进行。 注意:一个泄漏检测器溶液的用途是允许进行分类源的"无泄漏"。抱着酒瓶直立，施加足够的泄漏检测解决方案，以支付接口。允许5-10秒，泡沫形成。 </li></ol></li><li>放置的检测仪器的探针入口在表面的组件接口。移动探头沿界面周边同时观察仪读出，注意考虑了仪器的延迟响应时间。 </li><li>慢慢采样，其中泄漏指示直到获得最大抄表的接口。 </li><li>离开探头入口在该最大读取位置约两倍仪器的响应时间（20秒）。如果最大观察到的仪表读数大于百万分之一（ppm）500份，记录更大，并且报告结果。点击取泄漏图像进行报告。 </li><li>另外，使用红外成像设备慢慢扫描组件，以检查是否有泄漏。这种方法被批准作为一种替代工作实践，以检测在EPA方法21从设备泄漏 - 光气成像。 <ol><li>打开相机，并允许稳定。 </li><li>取下镜头盖，并用相机屏幕上慢慢扫描组件泄漏。 注:的Opti标定气体想象的相机通常是昂贵的，但的确可以降低扫描组件泄漏所需的时间。高灵敏度模式的使用可能需要小的泄漏。 </li><li>如果泄漏与摄像头，无论是视频记录或报告目的的图像检测。标记为与FFS后续量化泄漏位置。 </li></ol></li></ol> 5.泄漏率定量注:泄漏率数量可能在同一时间，泄漏检测或泄漏的库存完成后完成。进入网站，泄露数据后的新泄漏按钮下发生的量化。用户必须选择是否使用本地或全局背景。在这两种情况下，系统将控制适当的电磁阀和记录定时样本。一旦背景已经采取，泄漏应量化三次或从三个方向，以保证正常的泄漏捕获。该系统将分析三个测量并报告方差。用户可以保存数据泄漏（单独和平均），重复采集，或分类源为变量。 <ol><li>测量和记录甲烷背景浓度定期整个网站的访问，并与每一个泄漏量化。 注:这是高度重视，采取不同的背景的是一个类似的区域内和条件下，当扩张的空气可能含有附近泄漏的滑流的泄漏。 5.15 - 系统合并泄漏分析在下面讨论。 </li><li>任何量化确定泄漏。之前接近与样品软管泄漏确保接地母线是在与地面接触和剪辑片段的采样接地夹的项目中的问题。使用FFS，定位在多个点的采样软管周围的泄漏源的面积，以获得连续三次泄漏率quantifications该源，其中包括在连续记录样品流和样品浓度。 </li><l我&gt;调整全流率通过打开或关闭在鼓风机的吸入虹膜导管来增加体积流量。调整管阀，以确保最大的甲烷浓度是最高的校准值的10％之内，或最低的甲烷浓度高于背景浓度高至少2ppm的。 </li><li>在节目中，按量化泄漏按钮。一个选项，使用全局或局部的背景将提示用户。 </li><li>当从其他泄漏污染的疑虑，始终把本地背景。随着泄漏量化位置软管，单击乘坐市内背景。一旦完成该程序将提示用户量化泄漏。 注意:程序自动切换FFS的出口的采样位置到端口后面入口到采样软管的局部背景。采样软管必须在相同的测量位置，用于样品定量。 </li><li>重复录音功ð泄漏提示三次，尤其是在高环境风力条件的情况下，或在复杂的几何形状。 <ol><li>如果附加的量化值能方差为10％以上，调查，以确定该方差是在泄漏率仪器故障或变异的结果。 </li><li>如果在泄漏率变化的来源是由于仪器故障，补救故障和​​重新量化的来源。否则，分类的泄漏为"可变的"，并记录可疑病因。 </li></ol></li><li>在接近或由覆盖包围单个源的多个源的情况下，处理有问题的源极（S），作为使用的外壳泄漏量化的单一来源。使用盒选项卡来执行这种类型的量化。 <ol><li>制造外壳完全塑料布或掺入任一柔性的，不可渗透的材料制成，或者依靠一个永久封闭诸如压缩机壳体。 注:enclosURE允许量化设备来捕获从其境内元件泄漏并允许通过机箱中特意放置孔捕获的天然气稀释或永久罩通风口存在任何位置的天然气。 </li><li>允许被淡化的天然气是从外壳拉伸，实现了从温室气体传感器的稳定的读数。量化采样的持续时间进行使用的外壳是依赖于外壳的尺寸。 </li><li>在位于该定量样品从外壳使得稀释空气越过潜在的泄漏源（S）流吸引点，以减少采样允许稳定浓度读数时间</li></ol></li><li>如果需要的袋子样品，放置装袋盒的抽真空样品袋的温室气体传感器的出口。使用该软件，记录袋样品识别号码和屏幕上的计时器，以确保一个完整的袋子样品非现场分析已经采取。 </li></ol>

The authors, along with Mr. Christopher Rowe and Mr. Zachary Luzader have filed invention disclosures and provisional patents with West Virginia University's Research Corporation and Office of Technology Transfer to protect the intellectual property associated with this system.

为了提高准确性，并克服当前行业限制，我们创建了全流采样系统（FFS）甲烷定量。研究人员使用的系统中的各种在北美许多位置的形式。光谱的使用消除由C2 +化合物和非破坏性采样性质显著干扰允许泄漏替代分析异地的袋采样。 CNG燃料系统，LNG燃料系统，内燃机曲轴箱，管道，管件，接头，法兰，压缩机排气口，井口部件，水/:当与另一种风块系统已成功地，准确地量化从下列项目中的甲烷排放量相结合油气分离罐，阀门，天然气，井套管，和许多其他天然气相关的组件驱动气动执行机构。系统平台包括便携式车，在道路上和越野车。功耗确实需要使用通过标准的120 VAC连接的发电机或房子的力量。然而，通过本使用"网格"动力系统可在高流速，但仍处于配合使用延长线和长采样房屋的可移植性围绕感兴趣的特定部位取样。目前电池供电的系统已经降低性能作为使用电网电力消除电池充电状态的函数。 周期性校准协议已被开发并集成到用户的接口。协议应1-3之前，任何新的现场审核或在每月的最低完成。如果用户不勤奋地遵循协议，该系统可以根据或过报告的排放率，这可能会产生不利的温室气体报告影响。的协议的主要目的是确保精确的系统来估计与组分粒度​​总站点排放。如果统计分析被用于创建新的排放因素，那么每个非LEA王组件也必须记录。 泄漏检测方法可以是时间与使用手持设备的耗费。使用的光学气体成像相机可以显著减少泄漏检测所需的时间。摄像机必须能够测量包括甲烷的挥发性有机化合物。目前可用的商业单位对每小时（克/小时）大约0.8克检测泄漏率敏感性和取决于风力条件。成像设备也对温度敏感。一定要调整温标是必要的。极冷蒸气（深冷天然气）或过热蒸汽（蒸汽尾气等）可能会出现过度泄漏。随后的量化必须遵循准确地确定任何成像泄漏的实际泄漏率。红外摄像机的使用可以减少显著检漏库存，但对风力条件敏感。强风条件下，规模较小的泄漏可能diffu本身更迅速，更不会被发现。有疑问时，总是用一只手仔细检查召开甲烷检测。 一个用户友好的界面确保轻松和正确使用FFS的。集成的用户提示帮助用户沿着协议，并减少后处理工作。例如，一旦一个泄漏量化完毕（第5部分），平均泄漏率基于使用连续浓度的至少30秒的计算和流速的录音将被报告。用户提示将自动使用全局或局部背景浓度。简单的屏幕上的选择将导致电磁阀为正确的位置进行操作和样品。用户应遵守所有屏幕上的提示，以确保泄漏的准确定量。该计划将用于以下自动校正:全局或局部的背景;温度;质量流率（假定空气与二氧化碳和甲烷的校正）;湿度（从温室气体传感器测量）;温度（千卡ocouple - 环境条件冗余校验） 测量甲烷排放率的相对不确定性，除非情况±4.4％，其中随着浓度的测量接近本底浓度泄漏是无关紧要的。成分的不确定性的一个例子在表2中被提供。 <table fo:keep-together.within-page="1"><tbody><tr><td> 资源 </td><td> 不确定度（％） </td></tr><tr><td>甲烷传感器</td><td> 1 </td></tr><tr><td>甲烷传感器校准相关</td><td> 0.73 </td></tr><tr><td>甲烷气体瓶</td><td> 1 </td></tr><tr><td>零空气气瓶</td><td> 0.1 </td></tr><tr><td> LFE </td><td> 0.7 </td></tr><tr><td> MAF </td><td> 4 </td></tr><tr><td>差压模块</td><td> 0.025 </td></tr><tr><td>绝对压力模块</td><td> 0.06 </td></TR&gt; <tr><td>热电偶</td><td> 0.4 </td></tr><tr><td> MAF校准相关</td><td> 0.09 </td></tr><tr><td>气分</td><td> 0.5 </td></tr></tbody></table> 表2.组件不确定性。用来量化系统的不确定性独立分量不确定性。 总体而言，该系统和其方法，努力从各种来源准确量化的甲烷排放量已被证明是有益的。该系统具有可扩展性和用户友好。所开发的系统相比具有为±10％74，不确定性当前商业系统的±4.4％的不确定性。用适当的校准，该系统可以很容易地进行量化泄漏率高达140 SCFM相比，其能够具有充分的电池充电64,74最多8 SCFM定量泄漏的当前的商业系统。尽管该系统需要连接到室内电源，这提供了骗子的优势sistent采样率和采样速率比现有系统高得多。当前系统的最低检测限为0.24克/小时或3.0×10 -3 SCFM。用户界面减少后处理要求，并降低了报告的努力。此外，基于激光的传感器是无损到泄漏样品，其允许与多个分析仪65中的样品的直接测量。基于激光测量，也不需要为环境，小，大的泄漏浓度或传感器的转换，这有助于误差的其他来源独立的传感器。未来的研究重点放在FFS，其用户界面的持续优化。进一步的研究正在进行，结合实验研究数据和计算流体力学开发其他最佳实践，以确保一致的和最佳的测量技术。

最近的报告证实气候正在因人类活动的变化，并进一步变化是不可避免的1。气候变化从增加大气中的温室气体（GHG）的浓度发生。二氧化碳（CO 2）和甲烷是2最大的温室气体的贡献者。 二氧化碳和甲烷来自自然过程和人类活动的起源3。 二氧化碳和甲烷目前的大气水平在过去的两个世纪中，分别增加了31％和151％，而甲烷浓度为2％，每年4-6个的速度增加。甲烷和二氧化碳的排放量的气候影响取决于视为甲烷具有较短的大气寿命相对于CO 2 7的周期。甲烷的大气寿命为12-17岁，之后氧化成二氧化碳发生8。甲烷的影响比CO大于72倍<sUB&gt; 2的20年间9。上的质量的基础上，甲烷是在超过100年间10在大气中的比的 CO 2捕集热23倍更有效的。甲烷和CO 2占10％，总美国（US）的温室气体排放11的82％。人为来源全球甲烷排放量是大约60％，其余是从天然来源8,10。 在2009年，未燃烧的生产井和本地分配网络之间的甲烷排放量相当了毛美国天然气生产的2.4％（1.9-3.1％在95％置信水平）12。未燃烧的甲烷排放量，不仅对环境有害，而且还表示向天然气公司13巨大的成本。分析人士估计，天然气行业每年超过$ 2十亿美元，因为甲烷泄漏和通风14输了。未燃烧排放classifIED为逃犯或排气15,16。溢散指气体从工艺或设备，例如阀，法兰，或管件无意地 ​​释放到周围空气17，18。通风指气体的有意释放从设备或操作处理至环境空气，如气动致动器19。在陆上石油和天然气设施，无组织排放约占〜的甲烷排放总量20的30％。 2011年，美国环境保护署（EPA）估计超过600万吨逃犯甲烷的天然气系统，超出温室气体排放量逃脱（CO 2当量在100年间），通过发射美国所有的钢铁，水泥和铝生产设施结合21。 在天然气的气候影响的决心存在由于缺乏相关的EM准确而可靠的估计数的临界间隙issions。然而，有一个无组织的甲烷排放量中精确地测量和报告这些值出现在天然气的生命周期，并进一步研究的每个阶段的共识是重要的19。有研究报道，从具体部门的无组织排放与结果不同的19级，22-28通过多达十二个订单。缺乏公认的行业标准和在泄漏检测和漏量化的字段相一致的规定的短缺使得能够使用的各种试验方法和设备，具有一些测量技术高达±50％29-35的准确性。因此，相当大的不确定性存在于发射在天然气生命周期19，28，33，36-39逃犯甲烷的量。 图1示出了在已发表 ​​的文献可变性的量在与天然气的生活相关联的测量和估计的甲烷排放量循环。 图1 </stroNG&gt;显示发出占总天然气产量的百分比平均发表逃犯甲烷排放量。如果未给的平均值取公布范围的平均值。 23研究之间的标准偏差是3.54，最低和最高值相差96.5％。 <img alt="图1" src="/files/ftp_upload/54179/54179fig1.jpg" /> 图1.逃犯甲烷排放量。发布时间平均排放在总天然气产量13，27，40-59的百分比逃犯甲烷排放量。 <a href="https://www.jove.com/files/ftp_upload/54179/54179fig1large.jpg" target="_blank">请点击此处查看该图的放大版本。</a> 目前，无组织排放的总量，部分原因是测量不确定度和缩放技术目前尚不清楚。如果没有准确的甲烷排放测量，政策制定者无法对此事做出明智的选择。目前的文献综述确定了天然气的溢散排放的量化三种主要方法:套袋，示踪气体，和市售高流量采样器。 装袋方法包括放置一个外壳在一个&#39;袋&#39;或热门周围无组织排放源60的形式。有装袋方法的两种变化。在一种，清洁气体的已知的流速（通常为惰性的）穿过外壳以创建用于测量的充分混合的环境。一旦达到平衡，气体样品从袋收集和测量。逃犯发射率从通过外壳61内的外壳和稳态甲烷浓度的清洁气体的测量流量来确定。根据外壳和泄漏的大小，以达到漏率测量必要的稳态条件所需的时间是最小61 20 15之间通过。装袋方法能够在最方便的组件应用。然而，这可能不适合于异常形状的部件。这种方法类型能够测量泄漏大小不等，从每分钟0.28立方米（ 立方米 /分钟）大6.8米3 /分60。另套袋技术被称为校准装袋到。在这里，已知体积的袋周围无组织排放源密封。逃犯排放率是基于该袋的扩张所需的时间来计算，并校正到标准条件。 示踪气体量化方法基于流经逃犯源测量示踪气体浓度的无组织排放率。通常使用的示踪气体是氦，氩，氮，六氟化硫，等等。无组织排放速率从示踪气体的已知释放速率的附近散逸源的比率来确定，示踪和fugi的顺风浓度的测量略去源气体，和逆风基线24。无组织排放率仅为有效承担两个源62相同的分散性和完全混合。这意味着该示踪剂以类似的速度和高度接近逃犯源释放，并且顺风测量距离充分混合羽状。该方法是耗时的，并且不提供用于分量级粒度63。 市售大容量采样系统由一个背包内打包一个便携式电池供电仪器来量化无组织排放率64。周围渗漏位置的空气是通过一1.5英寸的内径的软管以足够高的流速吸入到采样器，它可以假设所有的泄漏气体的被捕获。 样品流率的计算与单位内的文氏管。对于低浓度的甲烷，0.05-5％的气体的体积，交流atalyst甲烷传感器是用来测量浓度。这种传感器是破坏性的样品内的甲烷和其他烃。为从5-100％的甲烷浓度（体积），一个热传感器采用。该系统采用一个单独的背景传感器和探针这相对于背景浓度的泄漏浓度校正。测量完成后，将样品用完后回大气从取样区域64远。这种方法可以在大多数辅助组件适用，但可测量流量的限制多达八个标准立方英尺每分钟（SCFM）。这个系统能够检测高达每小时30样品。最近，这种系统已显示出具有不同的精确度和关于来自催化传感器的热传感器65的过渡的问题。此外，该系统需要气体分数分析基于气体质量正确应用的响应因子 - 它不是甲烷具体。该系统已被广泛使用，并且可以通过提交报告的甲烷排放量65已归因于自上而下和自下而上的方法之间的差异。 由于这些方法和系统的限制，一新的量化系统的开发。农民田间学校采用了相同的设计理念，在汽车排放认证66-68使用稀释系统。农民田间学校是由哺养的防爆风机，通过一个质量流量传感器（MAF）和采样探头耗尽泄漏和稀释空气样品软管。试样探头通过取样管连接到基于激光甲烷分析仪。该分析仪使用空腔增强吸收为CH 4，CO 2，和H 2 O的测定该分析仪能够通过体积，CO 2的从0到20,000ppm的，和H 2 O在0到70,000 ppm的由0％至10％的测量的 CH 4。重复性/精度（1-Σ）此配置我小号&lt;0.6 ppb的CH 4，&lt;100 ppb的二氧化碳 ，而&lt;35ppm的的在H 2 O 69。将样品从流以恒定的体积速率拉伸。系统仪表用数据记录设备; 图2示出了FFS的示意图。前操作所述FFS，上采样器软管接地连接附连到表面，使系统接地。这是为了消散在软管的端部，这可能导致从通过软管气流任何静态电荷的预防措施。数据采集​​的发生要么是一款智能手机，平板电脑或笔记本电脑上。软件进行数据采集，处理和报告的发展。 图3提供了以下协议的用户界面的简要概述。 <img alt="图2" src="/files/ftp_upload/54179/54179fig2.jpg" /> 图2. FFS原理图和影像左转- FFS原理图和正确-压缩天然气（CNG）站审核期间便携式FFS <a href="https://www.jove.com/files/ftp_upload/54179/54179fig2large.jpg" target="_blank">请点击此处查看该图的放大版本。</a> <img alt="图3" src="/files/ftp_upload/54179/54179fig3.jpg" /> 图3.检测和定量项目概述，步骤和用户简述提示输入校准，恢复测试，和泄漏量化。 <a href="https://www.jove.com/files/ftp_upload/54179/54179fig3large.jpg" target="_blank">请点击此处查看该图的放大版本。</a>

<table><tbody><tr><td>Abaco DBX 97 mm&amp;nbsp;</td><td>Abaco Performance, LLC</td><td>http://www.abacoperformance.com/products.htm</td><td>mass air flow sensor</td></tr><tr><td>Ultraportable Greenhouse Gas Analyzer</td><td>Los Gatos Research</td><td>http://www.lgrinc.com/analyzers/ultraportable-greenhouse-gas-analyzer/</td><td>methane, CO&lt;sub&gt;2&lt;/sub&gt;, and water sensor</td></tr><tr><td>3AA20 Fume Exhauster&amp;nbsp;</td><td>Daytona</td><td>http://www.sustainablesupply.com/Dayton-3AA20-Exhauster-Fume-Smoke-p/w267066.htm?gclid=CI2Dm9ffrcgCFUYTHwodyusFRg&amp;amp;CAWELAID=1307486526</td><td>blower/dilutor</td></tr><tr><td>Eagle II&amp;nbsp;</td><td>RKI Instruments</td><td>http://www.rkiinstruments.com/pdf/eagle2brochure.pdf</td><td>Handheld detector</td></tr><tr><td>MCR 50&amp;nbsp;</td><td>Alicat Scientific</td><td>http://www.alicat.com/</td><td>calibrated on methane</td></tr><tr><td>Laminar Flow Element, Model Number: Z50MC2-6, Serial Number 707230-Y1</td><td>Meriam</td><td>http://www.meriam.com/product-category/laminar-flow-element/</td><td>calibrated on air</td></tr><tr><td>K-Type thermocouple</td><td>Omega</td><td>http://www.omega.com/</td><td></td></tr><tr><td>PTE-1 Calibrator</td><td>Heise</td><td>http://www.heise.com/products/calibrators/</td><td>handheld unit for use with Dressor modules</td></tr><tr><td>Model HQS-2&amp;nbsp;</td><td>Dresser/Ashcroft</td><td>http://www.ashcroft.eu/download/data%20sheet/englisch/MODULE_E.pdf</td><td>absolute pressure module</td></tr><tr><td>Model HQS-1&amp;nbsp;</td><td>Dresser/Ashcroft</td><td>http://www.ashcroft.eu/download/data%20sheet/englisch/MODULE_E.pdf</td><td>differential pressure module</td></tr><tr><td>Gas Divider - SGD-710C</td><td>Horiba</td><td>http://www.horiba.com/us/en/</td><td>calibrated gas divider</td></tr><tr><td>Methane (99.9%)</td><td>Mathenson TriGas</td><td>http://www.mathesongas.com/</td><td>pure methane for gas recovery test</td></tr><tr><td>Methane (&amp;#177;1%) 2.5%</td><td>Mathenson TriGas</td><td>http://www.mathesongas.com/</td><td>high concentration</td></tr><tr><td>Methane (&amp;#177;1%) 2,010&amp;nbsp;ppm</td><td>Mathenson TriGas</td><td>http://www.mathesongas.com/</td><td>low concentration</td></tr><tr><td>Ultra High Purity Nitrogen (UPHN)</td><td>Mathenson TriGas</td><td>http://www.mathesongas.com/</td><td>99.9% nitrogent gas</td></tr><tr><td>10 Liter Tedlar Bag</td><td>Dupont</td><td>http://www.dupont.com/products-and-services/membranes-films/pvf-films/brands/tedlar-pvf-films/uses-and-applications/tedlar-gas-sample-bag-applications.html</td><td>used for bag samples for alternative gas sampling</td></tr><tr><td>PET-7018Z</td><td>ICP DAS USA</td><td>http://www.icpdas-usa.com/pet_7018z.html</td><td>DAQ unit</td></tr><tr><td>Edgetech Dew Prime Hyrgrometer</td><td>Edgetech Instruments</td><td>http://www.edgetechinstruments.com/moisture-humidity</td><td>hygrometer for flowbench</td></tr><tr><td>Stainless steel Swagelok fittings (1/4 inch)</td><td>Swagelok</td><td>https://www.swagelok.com/products/fittings.aspx</td><td>tee and other fittings</td></tr><tr><td>PTFE Tubing</td><td>McMaster-Carr</td><td>http://www.mcmaster.com/#standard-hollow-tubing-(made-with-teflon-ptfe)/=z8xrzl</td><td>tubing for sampling and calibration</td></tr><tr><td>FLIR GF 320</td><td>FLIR</td><td>http://www.flir.com/ogi/display/?id=55671</td><td>infrared camera</td></tr><tr><td>CGA 580 Regulator</td><td>Airgas</td><td>http://airgas.com/category/_/N-1z13vaq</td><td>UHPN regulator</td></tr><tr><td>CGA 350 Regulator</td><td>Airgas</td><td>http://airgas.com/category/_/N-1z13vaq</td><td>Methane in nitrogen regulator</td></tr><tr><td>Leak detection solution (Snoop)</td><td>Swagelok</td><td>https://www.swagelok.com/search/find_products_home.aspx?show_results=Y&amp;amp;item=5e208092-ed6c-4251-9202-ed8a2aae5811</td><td>bubble solution for non-leak verification</td></tr></tbody></table>

design and use of a full flow sampling system (ffs) for the quantification of methane emissions

使用天然气的继续增加非常规页岩资源的发现和生产的增长。与此同时，天然气行业面临持续的甲烷排放量从审查在整个供应链中，由于甲烷的相对较高的全球变暖潜能值（25-84x的二氧化碳，根据美国能源信息管理局）。目前，各种不同的不确定性的技术存在来测量或估计从部件或设施的甲烷排放量。目前，只有一个商用系统可用于组件级别的排放和最近的报告中定量强调了它的弱点。 为了提高准确性，提高测量灵活性，我们已经设计，开发和实施了一种新的全流量取样系统（FFS），用于基于交通排放测量原理的甲烷排放和温室气体的定量。在FFS是一个模块化系统，由一个防爆鼓风机（多个），空气质量流量传感器（S）（MAF），热电偶，试样探针，恒定体积取样泵，基于激光的温室气体传感器，数据采集装置，和分析软件的。所采用的鼓风机和软管配置依赖，电流FFS是能够实现的流速范围从40到1500标准立方英尺每分钟（SCFM）。基于激光的传感器的利用率减轻从更高级的烃（C2 +）的干扰。水蒸汽联合测量允许湿度修正。该系统是便携式的，具有多个配置为各种应用，从由一个人携带，以被安装在一个手绘车，公路上车辆的床，或从实用地形车（UTVs）的床。农民田间学校是能够量化的甲烷排放率在±4.4％的相对不确定性。农民田间学校已经证明，现实世界中操作的甲烷排放量的conventio发生的量化最终和远程设备。

多个FFS被开发和用于量化多种甲烷排放源。两个主要研究包括环境保护基金会的重型天然气汽车泵轮（PTW）的研究和巴内特协调运动（BCC）。该PTW研究的重点从重型天然气汽车的燃料系统，发动机曲轴箱甲烷排放的量化，压缩天然气储罐，液化天然气储罐，加油站设备，喷嘴和其他泄漏。 多FFS系统BCC过程中使用，它汇集了一流的专家从学术和研究设施，从全国各地收集整个天然气供应链中的甲烷排放量数据（生产，采集，加工，传输，存储和本地配送）通过飞机，车辆和地面测量的组合。在我们进行的自然甲烷排放的直接来源量化气体压缩机站，并使用开发的方法和FFS系统储存设施。从与通过就业农民田间学校获得的测量Barnett页岩研究成果的一部分已提交和同行审查会议和科学期刊上发表70-72。 对于这两种PTW和BCC，我们采用甲烷检漏设备调查现场组件，包括阀门，管道/管路，和其他组件携带或保持天然气。用手持式甲烷检测仪检测到泄漏。通过确定增加的甲烷浓度高于背景的泄漏位置的识别这种手持式探测器的帮助。一旦泄漏位置检测到超过浓度门槛，研究人员使用FFS量化泄漏率。该FFS泄漏样品通过连接到鼓风机的入口侧的软管收集。通过认证的爆炸PR传递的样本OOF鼓风机它被通过一个含有MAF和甲烷传感器的配管系统排出。该FFS系统能够在流量从40到1500 SCFM取决于系统配置采样。使用测得的样品流量和甲烷浓度，在SCFM或g泄漏率/算出小时。 校准数据为校准，以恒定流量通过该系统建立的。通过高压口和上LFE低压端口之间的压力差的测量，获得横跨LFE的压降。绝对压力从差动测量线的高压端口记录。进行测定，用相结合的差分/绝对压力计记录的校准压力。手持式单元中使用两个模块，一个用于绝对压力，和一个用于压力差。绝对压力模块是一个能够测量0-30 PSI ABSOLU的0.025％的不确定性TE功能。压差模块是能够从0到10英寸的水的测量用的0.06％的不确定性的。该气体样品的温度是使用K型热电偶为±1.1℃或0.4％的不确定性测量LFE之前。从MAF的输出电压通过一个模拟数据采集卡的记录。流速用在鼓风机的入口可变节流阀改变。校准是为各种流速对MAF执行，范围可达1500 SCFM。 作为空气中以恒定的流速通过LFE既和MAF，压力差，样品的温度，绝对压力，和MAF电压通过被同时记录。横跨LFE，样品的温度，并且绝对压力的压力差被用来计算通过LFE使用由制造商提供的系数的实际体积流率。实际体积流率转换为标准体积流量。通过LFE标准体积流率与从MAF获得的电压， 如图4。 <img alt="图4" src="/files/ftp_upload/54179/54179fig4.jpg" /> 用NIST溯源LFE农林部图4. MAF输出信号校准。多点校准（参见第1至1.7）。 <a href="https://www.jove.com/files/ftp_upload/54179/54179fig4large.jpg" target="_blank">请点击此处查看该图的放大版本。</a> A为对数据集来确定该方程的最好拟合系数和计算方程的回归统计，R 2，以检查数据集之间的相关性进行最小二乘回归。一旦方程被开发，通过LFE涉及的MAF电压到流率，比较了实际之间进行<html>流率和MAF的测定流量。这示于图5。 <img alt="图5" src="/files/ftp_upload/54179/54179fig5.jpg" /> 图5. MAF流量相关性。MAF测量的流量暗算LFE实际体积流量（见第1.8）。 <a href="https://www.jove.com/files/ftp_upload/54179/54179fig5large.jpg" target="_blank">请点击此处查看该图的放大版本。</a> 用24,730 ppm的甲烷气体钢瓶甲烷传感器的校准示于图6。从施加外部校正之后的实际甲烷浓度的平均偏差是0.7％。从施加外部校正之后的实际甲烷浓度最大偏差为1.9％。 /54179/54179fig6.jpg"/&gt; 图6.甲烷传感器校准/检定，使用除以校准气体和NIST溯源瓶装甲烷（见第2节）的甲烷传感器的外部核查。 <a href="https://www.jove.com/files/ftp_upload/54179/54179fig6large.jpg" target="_blank">请点击此处查看该图的放大版本。</a> 已取得和应用校准曲线后，整个系统的验证是通过完成一个气体回收试验进行。其中甲烷的已知质量注入使用校准MFC中的甲烷和由系统指示注入的真实质量的质量之间进行比较的系统。这个程序是基于联邦法规法典确保全流稀释隧道的捕获和测量能力要求的丙烷注射的普遍做法，其中碳氢化合物的排放量已知体积注入measurem使用独立校准装置和系统的恢复能力耳鼻喉科系统进行验证。该控制MFC进行校准的甲烷。 MFC的设定在20两种流量和99.9％的纯甲烷的30 SLPM。结果列于表1中为140 SCFM的系统流量。结果表明，在两种情况下，FFS系统测量值分别为预期的4.4％之内。在两次测量的平均误差是+ 2.2％。 <table fo:keep-together.within-page="1"><tbody><tr><td> MFC设定点 </td><td> FFS恢复 </td><td> 恢复错误 </td></tr><tr><td> SLPM </td><td> SLPM </td><td> ％ </td></tr><tr><td> 20 </td><td> 20.3 </td><td> 1.70％ </td></tr><tr><td>三十</td><td> 30.8 </td><td> 2.7 </td></tr><tr><td colspan="2">平均</td><td> 2.20％ </td></tr></tbody></table>在两个不同的模拟泄漏率表1 FFS恢复结果。甲烷回收试验。 在野外数据采集 连续泄漏源 图6示出的连续的泄漏源，例如， 图7可分成4个独立的区域，广告。这些措施包括以下部分:背景，接近泄漏源，泄漏捕捉，并从泄漏源撤退。在C部分发生泄漏量化。经审查，同时泄漏的第二次重复测量后，D节发生图8显示了泄漏的红外摄像机观察-左边显示的甲烷羽自然分散-正确显示，FFS收集所有泄漏再加上额外的稀释空气。 <img alt="图7" src="/files/ftp_upload/54179/54179fig7.jpg" /><br/&gt; 图7.传统的连续泄漏 ，显示出不同的测量部分连续泄漏源实时跟踪（A:背景，B:接近泄漏，C:平均泄漏率，D:从泄漏撤退）（见第5 - 5.6）。 <a href="https://www.jove.com/files/ftp_upload/54179/54179fig7large.jpg" target="_blank">请点击此处查看该图的放大版本。</a> <img alt="图8" src="/files/ftp_upload/54179/54179fig8.jpg" /> 。泄漏的接头和权- - 图8.泄漏左派的红外图像 ，从相同的接头（参见4.6节）捕获/量化泄漏<a href="https://www.jove.com/files/ftp_upload/54179/54179fig8large.jpg" target="_blank">，请点击此处查看该图的放大版本。</a> 间歇性泄漏源 从浓度添得到与某个事件相关联的总质量E到数值积分的应用程序配置文件。为了规避一些与梯形规则相关联的低效率，自适应复合辛普森的规则是就业。这种自适应的积分型方法允许在急剧变化的73区自动步长调整。 需要对所收集的数据的数值积分是适用于间歇性事件，例如图9示出的甲烷排放量的间歇源的一个例子。本实施例是一种用于车辆加油事件。背景是从150-240秒和425秒，直到最后表示。此特定事件是一个单一的液化天然气（LNG）的罐的加油。泄漏率是综合判断发射的总质量（9.5克）。 <img alt="图9" src="/files/ftp_upload/54179/54179fig9.jpg" /> 图9。间歇性泄漏。间歇&#39;泄露&#39;从车辆加油事件源（浓度[PPM]，稀释流量[SCFM]，泄漏率[克/小时]）（见第5节）。 <a href="https://www.jove.com/files/ftp_upload/54179/54179fig9large.jpg" target="_blank">请点击此处查看大图这个数字。</a> 来源汇总 由于多个源在紧接近是和由覆盖封闭的，压缩机单元被聚集，并作为泄漏量化单个源处理。 图10示出了从一个聚合源测量的甲烷排放量的一个例子。这些数据是从一个时间 - 填充CNG压缩机壳体收集。压缩机壳体是为约119分钟，连续地测定。遇到的压缩机单元确实显示变性的量小。在泄漏率和甲烷浓度的变化是由于压力波动和可变泄漏压缩机密封。对于聚集的源，收集数据长时间，并计算平均泄漏率。 <img alt="图10" src="/files/ftp_upload/54179/54179fig10.jpg" /> 图10.集合示例。泄漏率，流量和从汇总的时间浓度数据填写CNG压缩机壳体（压缩机和风扇关闭）（见5.7）。 <a href="https://www.jove.com/files/ftp_upload/54179/54179fig10large.jpg" target="_blank">请点击此处查看该图的放大版本。</a>

Watch this Scientific Journal Video about Design and Use of a Full Flow Sampling System FFS for the Quantification of Methane Emissions at JoVE.com

用于甲烷排放量化的全流采样系统 FFS 的设计和使用工程|视频

Design and Use of a Full Flow Sampling System FFS for the Quantification of Methane Emissions

We have designed, developed, and implemented a novel full flow sampling system (FFS) for quantification of methane emissions and greenhouse gases from across the natural gas supply chain.

设计和全流采样系统（FFS）的使用甲烷排放的量化

The use of natural gas continues to grow with increased discovery and production of unconventional shale resources. At the same time, the natural gas ...

design-use-full-flow-sampling-system-ffs-for-quantification-methane

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Design and Use of a Full Flow Sampling System (FFS) for the Quantification of Methane Emissions

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Introduction: Matter and Measurement

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16.6K 次观看.  West Virginia University. We have designed, developed, and implemented a novel full flow sampling system (FFS) for quantification of methane emissions and greenhouse gases from across the natural gas supply chain.

视频: Design and Use of a Full Flow Sampling System FFS for the Quantification of Methane Emissions

The Use of an Automated System (GreenFeed) to Monitor Enteric Methane and Carbon Dioxide Emissions from Ruminant Animals

Ruminant animals (domesticated or wild) emit methane (CH4) through enteric fermentation in their digestive tract and from decomposition of manure during storage. These processes are the major sources of greenhouse gas (GHG) emissions from animal production systems. Techniques for measuring enteric CH4 vary from direct measurements (respiration chambers, which are highly accurate, but with limited applicability) to various indirect methods (sniffers, laser technology, which are practical, but with variable accuracy). The sulfur hexafluoride (SF6)&#160;tracer gas method is commonly used to measure enteric CH4 production by animal scientists and more recently, application of an Automated Head-Chamber System (AHCS) (GreenFeed, C-Lock, Inc., Rapid City, SD), which is the focus of this experiment, has been growing. AHCS is an automated system to monitor CH4 and carbon dioxide (CO2) mass fluxes from the breath of ruminant animals. In a typical AHCS operation, small quantities of baiting feed are dispensed to individual animals to lure them to AHCS multiple times daily. As the animal visits AHCS, a fan system pulls air past the animal&#8217;s muzzle into an intake manifold, and through an air collection pipe where continuous airflow rates are measured. A sub-sample of air is pumped out of the pipe into non-dispersive infra-red sensors for continuous measurement of CH4 and CO2 concentrations. Field comparisons of AHCS to respiration chambers or SF6 have demonstrated that AHCS produces repeatable and accurate CH4 emission results, provided that animal visits to AHCS are sufficient so emission estimates are representative of the diurnal rhythm of rumen gas production. Here, we demonstrate the use of AHCS to measure CO2 and CH4 fluxes from dairy cows given a control diet or a diet supplemented with technical-grade cashew nut shell liquid.

The Use of an Automated System GreenFeed to Monitor Enteric Methane and Carbon Dioxide Emissions from Ruminant Animals

Accuracy and precision of the techniques used to measure methane emissions from ruminant animals are critically important for the success of greenhouse gas mitigation efforts. This manuscript describes the principles and operation of an automated system to monitor methane and carbon dioxide mass fluxes from the breath of ruminant animals.

自动系统（绿色饲料）的用于监视肠道的甲烷和二氧化碳从反刍动物排放

Ruminant animals (domesticated or wild) emit methane (CH4) through enteric fermentation in their digestive tract and from decomposition of manure during ...

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Calibrated Passive Sampling - Multi-plot Field Measurements of NH3 Emissions with a Combination of Dynamic Tube Method and Passive Samplers

Agricultural ammonia (NH3) emissions (90% of total EU emissions) are responsible for about 45% airborne eutrophication, 31% soil acidification and 12% fine dust formation within the EU15. But NH3 emissions also mean a considerable loss of nutrients. Many studies on NH3 emission from organic and mineral fertilizer application have been performed in recent decades. Nevertheless, research related to NH3 emissions after application fertilizers is still limited in particular with respect to relationships to emissions, fertilizer type, site conditions and crop growth. Due to the variable response of crops to treatments, effects can only be validated in experimental designs including field replication for statistical testing. The dominating ammonia loss methods yielding quantitative emissions require large field areas, expensive equipment or current supply, which restricts their application in replicated field trials. This protocol describes a new methodology for the measurement of NH3 emissions on many plots linking a simple semi-quantitative measuring method used in all plots, with a quantitative method by simultaneous measurements using both methods on selected plots. As a semi-quantitative measurement method passive samplers are used. The second method is a dynamic chamber method (Dynamic Tube Method) to obtain a transfer quotient, which converts the semi-quantitative losses of the passive sampler to quantitative losses (kg nitrogen ha-1). The principle underlying this approach is that passive samplers placed in a homogeneous experimental field have the same NH3 absorption behavior under identical environmental conditions. Therefore, a transfer co-efficient obtained from single passive samplers can be used to scale the values of all passive samplers used in the same field trial. The method proved valid under a wide range of experimental conditions and is recommended to be used under conditions with bare soil or small canopies (&#60;0.3 m). Results obtained from experiments with taller plants should be treated more carefully.

Calibrated Passive Sampling - Multi-plot Field Measurements of NH3 Emissions with a Combination of Dynamic Tube Method and Passive Samplers

Ammonia emissions are a major threat to the environment by eutrophication, soil acidification and fine particle formation and stem mainly from agricultural sources. This method allows ammonia loss measurements in replicated field trials enabling statistical analysis of emissions and of relationships between crop development and emissions.

校准被动采样 - NH多情节场测量<sub&gt; 3</sub&gt;与动态管法和被动采样的组合排放

Agricultural ammonia (NH3) emissions (90% of total EU emissions) are responsible for about 45% airborne eutrophication, 31% soil acidification and 12% ...

Convergent Polishing: A Simple, Rapid, Full Aperture Polishing Process of High Quality Optical Flats &amp; Spheres

Convergent Polishing is a novel polishing system and method for finishing flat and spherical glass optics in which a workpiece, independent of its initial shape (i.e., surface figure), will converge to final surface figure with excellent surface quality under a fixed, unchanging set of polishing parameters in a single polishing iteration. In contrast, conventional full aperture polishing methods require multiple, often long, iterative cycles involving polishing, metrology and process changes to achieve the desired surface figure. The Convergent Polishing process is based on the concept of workpiece-lap height mismatch resulting in pressure differential that decreases with removal and results in the workpiece converging to the shape of the lap. The successful implementation of the Convergent Polishing process is a result of the combination of a number of technologies to remove all sources of non-uniform spatial material removal (except for workpiece-lap mismatch) for surface figure convergence and to reduce the number of rogue particles in the system for low scratch densities and low roughness. The Convergent Polishing process has been demonstrated for the fabrication of both flats and spheres of various shapes, sizes, and aspect ratios on various glass materials. The practical impact is that high quality optical components can be fabricated more rapidly, more repeatedly, with less metrology, and with less labor, resulting in lower unit costs. In this study, the Convergent Polishing protocol is specifically described for fabricating 26.5 cm square fused silica flats from a fine ground surface to a polished ~&#955;/2 surface figure after polishing 4 hr per surface on a 81 cm diameter polisher.

Convergent Polishing: A Simple, Rapid, Full Aperture Polishing Process of High Quality Optical Flats & Spheres

A novel optical polishing process, called &#8220;Convergent Polishing&#8221;, which enables faster, lower cost polishing, is described. Unlike conventional polishing processes, Convergent Polishing allows a glass workpiece to be polished in a single iteration and with high surface quality to its final surface figure without requiring changes to polishing parameters.

收敛抛光:高品质光学平面与球的一种简单，快速，全口径抛光工艺

Convergent Polishing is a novel polishing system and method for finishing flat and spherical glass optics in which a workpiece, independent of its initial ...

工程学

Characterizing Far-infrared Laser Emissions and the Measurement of Their Frequencies

The generation and subsequent measurement of far-infrared radiation has found numerous applications in high-resolution spectroscopy, radio astronomy, and Terahertz imaging. For about 45 years, the generation of coherent, far-infrared radiation has been accomplished using the optically pumped molecular laser. Once far-infrared laser radiation is detected, the frequencies of these laser emissions are measured using a three-laser heterodyne technique. With this technique, the unknown frequency from the optically pumped molecular laser is mixed with the difference frequency between two stabilized, infrared reference frequencies. These reference frequencies are generated by independent carbon dioxide lasers, each stabilized using the fluorescence signal from an external, low pressure reference cell. The resulting beat between the known and unknown laser frequencies is monitored by a metal-insulator-metal point contact diode detector whose output is observed on a spectrum analyzer. The beat frequency between these laser emissions is subsequently measured and combined with the known reference frequencies to extrapolate the unknown far-infrared laser frequency. The resulting one-sigma fractional uncertainty for laser frequencies measured with this technique is &#177; 5 parts in 107. Accurately determining the frequency of far-infrared laser emissions is critical as they are often used as a reference for other measurements, as in the high-resolution spectroscopic investigations of free radicals using laser magnetic resonance. As part of this investigation, difluoromethane, CH2F2, was used as the far-infrared laser medium. In all, eight far-infrared laser frequencies were measured for the first time with frequencies ranging from 0.359 to 1.273 THz. Three of these laser emissions were discovered during this investigation and are reported with their optimal operating pressure, polarization with respect to the CO2 pump laser, and strength.

We describe the generation of far-infrared radiation using an optically pumped molecular laser along with the measurement of their frequencies with heterodyne techniques. The experimental system and techniques are demonstrated using difluoromethane (CH2F2) as the laser medium whose results include three new laser emissions and eight measured laser frequencies.

表征远红外激光辐射及其频率的测量

The generation and subsequent measurement of far-infrared radiation has found numerous applications in high-resolution spectroscopy, radio astronomy, and ...

Characterization of Full Set Material Constants and Their Temperature Dependence for Piezoelectric Materials Using Resonant Ultrasound Spectroscopy

During the operation of high power electromechanical devices, a temperature rise is unavoidable due to mechanical and electrical losses, causing the degradation of device performance. In order to evaluate such degradations using computer simulations, full matrix material properties at elevated temperatures are needed as inputs. It is extremely difficult to measure such data for ferroelectric materials due to their strong anisotropic nature and property variation among samples of different geometries. Because the degree of depolarization is boundary condition dependent, data obtained by the IEEE (Institute of Electrical and Electronics Engineers) impedance resonance technique, which requires several samples with drastically different geometries, usually lack self-consistency. The resonant ultrasound spectroscopy (RUS) technique allows the full set material constants to be measured using only one sample, which can eliminate errors caused by sample to sample variation. A detailed RUS procedure is demonstrated here using a lead zirconate titanate (PZT-4) piezoceramic sample. In the example, the complete set of material constants was measured from room temperature to 120 &#176;C. Measured free dielectric constants <img alt="Equation 1" src="/files/ftp_upload/53461/image001.jpg" /> and&#160;<img alt="Equation 2" src="/files/ftp_upload/53461/image002.jpg" /> were compared with calculated ones based on the measured full set data, and piezoelectric constants d15 and d33 were also calculated using different formulas. Excellent agreement was found in the entire range of temperatures, which confirmed the self-consistency of the data set obtained by the RUS.

This protocol describes the procedure of measuring the temperature dependence of the full set material constants of piezoelectric materials using resonant ultrasound spectroscopy (RUS).

全套材料常数表征及其温度依赖性的压电材料使用共振超声波谱

During the operation of high power electromechanical devices, a temperature rise is unavoidable due to mechanical and electrical losses, causing the ...

Assessment of Methane and Nitrous Oxide Fluxes from Paddy Field by Means of Static Closed Chambers Maintaining Plants Within Headspace

This protocol describes the measurement of greenhouse gas (GHG) emissions from paddy soils using the static closed chamber technique. This method is based on the diffusion theory. A known volume of air overlaying a defined soil area is enclosed within a parallelepiped cover (named &#34;chamber&#34;), for a defined period of time. During this enclosure period, gases (methane (CH4) and nitrous oxide (N2O)) move from soil pore air near their microbial source (i.e., methanogens, nitrifiers, denitrifiers) to the chamber headspace, following a natural concentration gradient. Fluxes are then estimated from chamber headspace concentration variations sampled at regular intervals throughout the enclosure and then analyzed with gas chromatography. Among the techniques available for GHG measurement, the static closed chamber method is suitable for plot experiments, as it does not require large homogenously treated soil areas. Furthermore, it is manageable with limited resources and can identify relationships among ecosystem properties, processes, and fluxes, especially when combined with GHG driving force measurements. Nevertheless, with respect to the micrometeorological method, it causes a minimal but still unavoidable soil disturbance, and allows a minor temporal resolution. Several phases are key to the method implementation: i) chamber design and deployment, ii) sample handling and analyses, and iii) flux estimation. Technique implementation success in paddy fields demands adjustments for field flooding during much of the cropping cycle, and for rice plant maintenance within the chamber headspace during measurements. Therefore, the additional elements to be considered with respect to the usual application of non-flooded agricultural soils consist of devices for: i) avoiding any unintended water disturbance that could overestimate fluxes, and ii) including rice plants within the chamber headspace to fully consider gases emitted through aerenchyma transportation.

The overall goal of this protocol is to measure greenhouse gas emissions from paddy fields using the static closed chamber technique. The measurement system needs specific adjustments due to the presence of both a permanent water layer in the field and of the plants within the chamber headspace.

用静止封闭室维持顶空装置对稻田甲烷和一氧化二氮通量的评价

This protocol describes the measurement of greenhouse gas (GHG) emissions from paddy soils using the static closed chamber technique. This method is based ...

Standardized Method for Measuring Collection Efficiency from Wipe-sampling of Trace Explosives

One of the limiting steps to detecting traces of explosives at screening venues is effective collection of the sample. Wipe-sampling is the most common procedure for collecting traces of explosives, and standardized measurements of collection efficiency are needed to evaluate and optimize sampling protocols. The approach described here is designed to provide this measurement infrastructure, and controls most of the factors known to be relevant to wipe-sampling. Three critical factors (the applied force, travel distance, and travel speed) are controlled using an automated device. Test surfaces are chosen based on similarity to the screening environment, and the wipes can be made from any material considered for use in wipe-sampling. Particle samples of the explosive 1,3,5-trinitroperhydro-1,3,5-triazine (RDX) are applied in a fixed location on the surface using a dry-transfer technique. The particle samples, recently developed to simulate residues made after handling explosives, are produced by inkjet printing of RDX solutions onto polytetrafluoroethylene (PTFE) substrates. Collection efficiency is measured by extracting collected explosive from the wipe, and then related to critical sampling factors and the selection of wipe material and test surface. These measurements are meant to guide the development of sampling protocols at screening venues, where speed and throughput are primary considerations.

Optimized sampling protocols and the development of new wipe materials can be facilitated by standardized measurements of collection efficiency from wipe-sampling. Our approach for sampling trace explosives uses an automated device to control speed, force, and distance during wipe-sampling followed by extraction of collected explosives.

从微量炸药的擦拭取样测量收集效率的标准化方法

One of the limiting steps to detecting traces of explosives at screening venues is effective collection of the sample. Wipe-sampling is the most common ...

Combustion Chemistry of Fuels: Quantitative Speciation Data Obtained from an Atmospheric High-temperature Flow Reactor with Coupled Molecular-beam Mass Spectrometer

This manuscript describes a high-temperature flow reactor experiment coupled to the powerful molecular beam mass spectrometry (MBMS) technique. This flexible tool offers a detailed observation of chemical gas-phase kinetics in reacting flows under well-controlled conditions. The vast range of operating conditions available in a laminar flow reactor enables access to extraordinary combustion applications that are typically not achievable by flame experiments. These include rich conditions at high temperatures relevant for gasification processes, the peroxy chemistry governing the low temperature oxidation regime or investigations of complex technical fuels. The presented setup allows measurements of quantitative speciation data for reaction model validation of combustion, gasification and pyrolysis processes, while enabling a systematic general understanding of the reaction chemistry. Validation of kinetic reaction models is generally performed by investigating combustion processes of pure compounds. The flow reactor has been enhanced to be suitable for technical fuels (e.g. multi-component mixtures like Jet A-1) to allow for phenomenological analysis of occurring combustion intermediates like soot precursors or pollutants. The controlled and comparable boundary conditions provided by the experimental design allow for predictions of pollutant formation tendencies. Cold reactants are fed premixed into the reactor that are highly diluted (in around 99 vol% in Ar) in order to suppress self-sustaining combustion reactions. The laminar flowing reactant mixture passes through a known temperature field, while the gas composition is determined at the reactors exhaust as a function of the oven temperature. The flow reactor is operated at atmospheric pressures with temperatures up to 1,800 K. The measurements themselves are performed by decreasing the temperature monotonically at a rate of -200 K/h. With the sensitive MBMS technique, detailed speciation data is acquired and quantified for almost all chemical species in the reactive process, including radical species.

An investigation of the oxidative combustion chemistry of novel biofuels, fuel components, or jet fuels by comparison of quantitative speciation data is presented. The data can be used for kinetic model validation and enables fuel assessment strategies.This manuscript describes the atmospheric high-temperature flow reactor and demonstrates its capabilities.

燃料燃烧化学: 用耦合分子束质谱仪从大气高温流反应器中获得的定量形态数据

This manuscript describes a high-temperature flow reactor experiment coupled to the powerful molecular beam mass spectrometry (MBMS) technique. This ...

化学

用于食物垃圾和污泥厌氧消化的呼吸测定方案

Measuring Biomethane Potential of Food Scrap Waste Anaerobically Co&#45;Digested with Waste&#45;Activated Sludge Using Respirometry

The use of respirometry to study the biokinetics of microbiota treating wastewater or digesting wastewater sludges has become more prevalent over the last few decades. The use of respirometry to examine the biokinetics of anaerobic microbiota co-digesting organic waste streams such as wastewater sludge and food scrap is an area of active research. To date, no visualized protocol has been published on the topic. Accordingly, in this protocol, we configured a respirometer to measure methane production and flow rate over time using three different food-to-microorganism (F:M) ratios and food scrap waste and waste-activated sludge as substrates. The resulting data, coupled with substrate utilization measurements, provides the basis for understanding how different substrate concentrations influence the rate at which anaerobic microbiota produce methane. Additionally, this protocol presents a method to develop biokinetic parameters (e.g., methane production rate constant and yield). Others can use this respirometry protocol to examine organic degradation under anaerobic conditions and develop microbial parameters.

作者聚焦：使用新型呼吸测定法方案推进厌氧微生物群研究

This protocol describes a best practice for determining methane production and microbial kinetic parameters using respirometry for anaerobic microbiota co-digesting food scrap waste and waste-activated sludge.

使用呼吸测定法测量厌氧共消化的食物残渣与废物活性污泥共消化的生物甲烷潜力

The use of respirometry to study the biokinetics of microbiota treating wastewater or digesting wastewater sludges has become more prevalent over the last ...

设计和全流采样系统（FFS）的使用甲烷排放的量化

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自动系统（绿色饲料）的用于监视肠道的甲烷和二氧化碳从反刍动物排放

校准被动采样 - NH多情节场测量

收敛抛光:高品质光学平面与球的一种简单，快速，全口径抛光工艺

表征远红外激光辐射及其频率的测量

全套材料常数表征及其温度依赖性的压电材料使用共振超声波谱

用静止封闭室维持顶空装置对稻田甲烷和一氧化二氮通量的评价

从微量炸药的擦拭取样测量收集效率的标准化方法

燃料燃烧化学: 用耦合分子束质谱仪从大气高温流反应器中获得的定量形态数据

使用呼吸测定法测量厌氧共消化的食物残渣与废物活性污泥共消化的生物甲烷潜力

使用呼吸测定法测量厌氧共消化的食物残渣与废物活性污泥共消化的生物甲烷潜力