杰恩莫罗博士和桑德拉·达席尔瓦博士，无论是从NIST，促成了该方法的早期版本。美国国土安全部，美国能源部的科学与技术局主办的生产这种材料的一部分的下间协议HSHQPM-15-T-00050与美国国家标准与技术研究院（NIST）。

1.仪器<ol><li>选择或制造器件与可移动的平面（参见图1中示意）。 注意:在此，使用TL-滑动/剥离测试仪但该器件的功能，如摩擦力的测定，即是没有必要在该方法中，并且可以增加成本通过简单的装置。 <ol><li>选择平面尺寸与由3cm的最小宽度为15厘米的最小长度。长度控制为单个采样路径（ 图1）的最大行进距离。 </li><li>选择与一个重复性在±10％的选定的速度移动以定义的速度从50-400毫米/秒的平面。范围是基于来自一个志愿者人口进行擦拭实验数据。 10 </li></ol></li><li>制造擦拭物夹持器（ 图2）。在补充资料CAD图纸。 <ol><li>包括夹紧机构保持擦拭暴露circulAR收集区直径30毫米。收集区是基于那里仪器的解吸区定义允许的收集区典型的ETD。 </li><li>包括收集区域后面可拆卸的软后盾，提供给偶数的动力分配。这是在污染的情况下，可以不另外通过清洗去除可拆卸。背衬可以由海绵橡胶的泡沫，如ASTM D1894 14，或另一种软的材料所描述的，如毛毡，切割成适当的尺寸。 注:在ASTM D1894中描述的海绵橡胶的性能包括:使用85±15千帕（12.5±2.5 psi）的压力时，以压缩泡沫的25％的能力来测量所需的柔软性。我们评估任何背衬材料的有效性通过使用力敏感膜8，10映射压力均匀地分布力。在整个收集区（压力30毫米 diame之三圆）可基于只针对受力均匀分布的总力来计算。 </li><li>包括在擦拭范围从约1至15 N（约100至1500克力）附接权重，以提供总的力（保持器和重量的组合重量）。在擦拭支架的重量设定最小力。力范围是基于数据从志愿者人口进行擦拭的实验中，其中平均力施加为7 N. 10的最大的力将通过确保行驶期间在表面上平滑运动的能力的限制。 </li><li>包括眼钩或类似装置用于连接一个约束线。导线抑制从平面的运动期间移动擦拭支架。导线应平行于表面或平面的运动期间处于轻微的正角。 </li></ol></li></ol> 2.材料的选择和仪器配置<ol><li>选择TE基于相似甄别环境ST表面。选择可包括合成皮革，金属，塑料，纸板，织物，即是平的，适合于测试装置的平面等使用的表面。非常灵活的表面可能需要由刚性表面进行备份，以防止擦拭采样过程中发生移动。 <ol><li>如果必要的话，清洁的溶剂（乙醇或甲醇通常是合适的）和/或通过吹离颗粒加压空气切割表面的尺寸。清洁表面之前立即擦拭取样的行为。 </li></ol></li><li>使用自认为是在擦拭取样用任何材料制成的湿巾。他们必须有最小尺寸覆盖在擦拭支架30毫米直径的圆形收集区和到位夹紧。 <ol><li>切湿巾的大小，如果需要放入抹持有人。 </li><li>测试中使用的第4节中描述以下过程来确定提取效率和空白铅污染之前的擦拭物的一个子集离子水平相对于RDX或其它污染物可能会干扰分析。 </li></ol></li><li>准备通过喷墨印刷阵列RDX粒子标准到聚四氟乙烯（PTFE）的基板。它们的制造和使用进行了详细审查的出版物中描述。 RDX 200ng的是最小量，给定的大约5纳克/毫升，并且最大量的定量技术的基础上，在指纹报告金额RDX的典型的分析检测限，应该是一个几微克。样品可以在冷藏条件下打印后举行长达30天。 注意:从这些标准获得的颗粒的尺寸范围为1微米至40微米的直径，模拟以及在处理塑料炸药12之后进行指纹的颗粒。转移的样品的面积分布取决于印刷阵列大小，但通常是一个5毫米的5mm的区域内;以及内30毫米直径的圆形采样区域。该协议使用通过当转印到测试表面具有已知的粒度分布和已知的区域分布喷墨打印产生RDX粒子标准。其它干转移样品13能如果相同的参数是已知的使用。不推荐通过直接沉积溶液到测试表面产生样本。 </li><li>配置和用于擦拭取样试验装置。 <ol><li>移动面上的起点位置（ 图1）。 </li><li>参照图3，放置一个测试表面，而不粘附它，该设备平面上。 <ol><li>从纸制备的模板，如在图1中的示意图中所示，并把它齐平，以在测试表面的边缘， 如图3。模板标志着擦拭开始位置和采样路径的位置和长度的位置。 </li><li>坚持在型板T○表面使用磁带。移动表面，与模板，来回上飞机，直到擦坐在起始位置时，限制线绷紧。移动的表面上，与模板，侧面到侧面的平面上，直到约束丝的中心向下的行进路径。 </li></ol></li><li>标记上，其中底物将被粘附，如上文所确定的平面的位置。坚持面，与模板，使用双面胶带的平面。 </li><li>使用软件控制的仪器输入行驶距离和行驶速度。 </li><li>发起的平面的运动，以测试该擦拭遵循的整个行驶距离的采样路径，以确保顺利的旅行。 注:的一些组合擦拭和测试表面可导致运动期间高水平的摩擦。跳跃和运动期间的擦拭起重是不希望的。该擦拭巾可从长行程的采样通道或某些偏离组合的擦拭和测试表面。最关键的因素是，以确保通过样品沉积位置擦拭通行证。调整限制线的角度可能有助于缓解这一问题。 </li><li>从样品测量存款行程的末端的位置的行进距离。 注:如果在样品在图1中放置采样路径的起点附近，如，行驶距离将处于其最大的测试表面的长度。较小的行进距离可以通过限制行驶的总长度来选择，或者通过移动所述样品的位置。 </li></ol></li></ol> 3.擦拭取样<ol><li>清洁测试表面并晾干。 </li><li>放置在顶加载天平表面，在上面放置一纸模板（参见2.4.2），在转角保持到位。 </li><li>拿在手上的颗粒样品，并使用掠照明来检查阵列完成。 </li><li>将手指存款的背后并把PTFE基板存款侧向下测试表面上，与所述标记的样品区域内的沉积物。沿着平移使用最少的10N的采样路径中的测试表面的PTFE基板（观察的重量上的平衡，以等于或超过千克力），以干转移的粒子。 <ol><li>对于具有条纹纹理测试表面，翻译沿表面垂直于条纹的PTFE基板，即使这是正交于采样路径。 </li></ol></li><li>使用掠照明检查干转印后的PTFE基板，以确保移除阵列。如果数组元素仍然存在，选择是否继续或放弃实验，重新开始。的选择将取决于从提取和分析，并在需要的表面上的最小质量的检测限。 </li><li>保留PTFE基材的转印效率的提取和判定。 </li><li>将测试表面上的平面在previously定义的位置，并坚持使用双面胶或等效的平面。 </li><li>加载所选抹到支架和附加适当的权重选择的力量。 </li><li>记录温度和湿度的实验附近在±2℃和±5％RH。 </li><li>附加约束丝的擦拭夹具与夹具擦拭侧朝下放置在试验表面上。立即启动飞机的运动。提起擦保持器时，将测试表面移动之后停止，并除去从所述保持器的擦拭。 </li></ol> 4.提取与分析<ol><li>提取和分析残留在PTFE转印基板任何RDX。 <ol><li>流速1mL甲醇中含在表面并进入2mL玻璃小瓶中的内标。使用同位素标记RDX作为内部标准。具有相似化学结构和物理性质的合适的类似物可以如果同位素标记的支架一起使用ARD不能获得。为RDX，附加上可接受的内标。将环四（HMX）。制备PTFE转印基板的方法，建议包裹纸环绕PTFE以最小化溶剂损失到纸张上。 </li><li>量化使用以前开发的分析协议解决方案。在此研究中使用的协议是基于电喷雾电离质谱（ESI-MS）。 </li></ol></li><li>提取和分析收集到的擦拭RDX。 <ol><li>切割擦拭材料下降到30毫米直径的圆形收集区域并放置一个2毫升的小玻璃瓶内的切口部。加入1毫升含内标甲醇。 </li><li>盖上小瓶和旋涡在10,000rpm下30秒。 </li><li>量化溶液尽可能迅速地防止被分析物和/或内部标准的再吸附到擦拭材料。提取尽可能的在一个小时内完成分析。 </li></ol></li><li>提取并分析关于PTFE的未使用的RDX粒子标准的一个子集相同的方式以得到基线起始质量为4.1。 </li><li>计算从PTFE基底转印效率（TE），以确定RDX的沉积在表面上的质量。 <img alt="式（1）" src="/files/ftp_upload/55484/55484eq1.jpg" /> 其中RDX 初始是提取的基线样品的平均附着量（步骤4.3）和RDX 保留 。是RDX的干转移（步骤4.1）之后剩余的PTFE基板上的质量。 </li><li>计算捕集效率（CE）的擦拭相对于所述表面上沉积的质量。 <img alt="公式2" src="/files/ftp_upload/55484/55484eq2.jpg" /> 其中RDX 擦拭距离擦拭（步骤4.2）中提取RDX的质量。 </li></ol> 5.质量控制<ol><li>进行最少重复3次。变异CE可以相对高，并且可能需要10次或更多的重复，以确定各采样因素的重要性。 <ol><li>清洁和再利用测试表面，用于重复如果空白测试表明清洁过程的功效。溶剂可能会影响表面纹理，以及任何需要使用它们的过程必须适用于所有的重复。 </li><li>使用新鲜的湿巾每个重复。 </li></ol></li><li>按照相同的程序，但用空白PTFE衬底测量过程空白。 </li></ol> 6.报告<ol><li>计算和报告TE为平均值和标准偏差和CE（n）的复制。 </li><li>报告1）类型的擦拭物，2）测试表面，3）的力，4）的速度，5）的行驶距离，6）温度，和7）湿度。 </li><li>报告中使用的类型和样品的细节。如果样品已制备比通过喷墨印刷，报告估计粒径和再现性等。 </li><li>报告任何其它因素，控制或观察到。 </li></ol>

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The authors have nothing to disclose. Certain commercial equipment, instruments, or materials are identified in this document. Such identification does not imply recommendation or endorsement by the National Institute of Standards and Technology, nor does it imply that the products identified are necessarily the best available for the purpose.

目前样品收集被视为限制步骤筛选的环境中提高检测能力。擦拭取样是需要测量和标准化，以评估当前的能力和支持新的采样材料和协议的发展。这里所描述的方法旨在提供这种测量的基础设施，以及控制大多数已知的因素是相关的擦拭取样。以前的工作已经表明，粒径，收集，测试表面，采样期间施加力擦拭，行驶距离是控制所有的重要因素。器乐方法允许用于在所施加的力的控制，擦拭的速度和行驶距离，并选择这些参数的值应落在预期在实际情况的范围内。该力是通过使用背衬重量在收集区域施加，并且应该小心，以实现均匀的力分布，以calc下乌拉特压力。 测试表面由用户选择，并应与实际筛查的环境中复制的采样挑战的预期范围内。采样擦拭物，以评估当前的实践和/或测量新设计的材料的效力选择。为了比较实验室之间的结果，同样的测试表面和擦拭物必须被使用，其可以通过指定关键参数或通过共享来自单个源购买的材料来完成。该ETD湿巾是市售的，但他们不断地在生产，不同批次可能有不同的属性。这些都是可以在将来通过实验室间的协调努力解决的问题。 用于评估收集效率的样品应与预计在实际生活中的物理特性。在爆炸物的情况下，我们已经制定了RDX的喷墨印刷解决方案来生产的方法微米大小的沉积物，能有效地转移到一个范围的底物和产生粒子沉积物尺寸范围从1至40微米。可替换地，可以使用固定大小的聚苯乙烯微球。吹打RDX溶液到特氟隆基板通常导致单存可能是相当大的，并转移到后表面的颗粒尺寸是未知的。这种方法可用于采样的研究，如果颗粒尺寸的特征，并显示出可重现的。 用于评估炸药采样效率描述的这种方法，但也可以应用于环保，核能，或法医学应用。的样品中，再次，应开发以匹配实际应用中，并且在颗粒的残基的情况下，相同类型的从聚四氟乙烯干式转印的是适当的。从比颗粒转移其它来源，例如从蒸汽冷凝，不同类型的样品所产生的表面污染可能更合适。 该技术的电流限制是不能改变的采样方向。当前的配置允许在一个单一的方向上的移动只，因此，对于通常发生在物体的领域采样方向变化无法控制。目前，我们正在解决这个需求通过将X - Y移动，并允许特定的抽样模式来填充区域。

筛选在机场和其他地点的爆炸物痕迹是在公众的反对恐怖主义威胁的保护中至关重要的一步。目前的做法主要侧重于表面污物擦拭取样从往货舱由人来处理项目，该人本身，和项目。收集擦巾使用通常基于收集的固体材料的热脱附商业炸药跟踪检测器（的ETD）立即分析的领域，与由离子迁移谱1或更最近，质谱检测。可用于样本采集和分析时间的总量是由需要尽量减少对旅客和货物吞吐量的影响有限。采样协议必须进行优化，以收集在最短的时间，这就要求标准化的测量，可衡量的因素擦拭收集重要最样品。 擦拭取样是用于在健康，环境和法规领域2，3，4，5，6，7取样表面污染的一般做法。典型的做法包括保持由手和采样使用一般的覆盖模式的固定区域内的擦拭。为了增加在擦拭因素，包括力和速度控制，我们开发了一种工具的方法来模拟擦拭采样8，其也被用于评估生物擦拭采样9效率。用于粘附测量的商业设备适应于目的;它包括下一个固定擦拭移动以固定的速度和距离的平坦表面。采样期间的力由设置在擦拭支架的顶部上的重量进行控制。感兴趣的表面（面料，PLASTICS，金属等 ）被放置在平坦表面上和颗粒样品放置在该表面上的固定区域。我们早期的工作中使用的聚苯乙烯胶乳微球作为试验粒子，粒径显示出具有对粒子收集的效果，具有小于（9微米）球收集更有效地大（42μm）的球体。我们还发现在收集效率有所改善，采样期间增加作用力，并观察在不同的表面收集和不同的抹布差异。 在随后的工作中，我们发现，聚苯乙烯颗粒可以通过继续收集后在表面擦拭，降低了表观收集效率10被再沉积。这是微量爆炸物探测的一个重要的考虑因素，在筛选的情况抽样商品，如手提箱，可相对于擦拭收集面积大，需要广泛的旅行DISTANCES覆盖项目的区域，甚至一个很小的比例。因此，样品收集后的表面上的行驶距离是一个重要因素，并且场协议通常定义之前每个分析所覆盖的最大容许距离。 微球的形状不像真正的炸药颗粒11，12和它们的化学和物理特性可以使他们爆炸物的不足模拟擦拭收集实验。为了解决这种限制，我们开发了含有炸药1,3,5- trinitroperhydro -1,3,5-三嗪（RDX）具有已知粒径的试验材料。该测试材料是通过在上基板特氟隆阵列的RDX溶液，与通过蒸发在所述阵列中的每个点处形成微米大小的固体沉积物的喷墨印刷纳升体积制成。所述沉积物通过摩擦在表面上转印到测试表面上，并且将所得部分ICLE大小由起始存款尺寸限定。所需的颗粒直径，如通过含有微量爆炸物指纹分析测定，为10至20μm。沉积物还可以通过吸取的溶液微升体积到特氟隆基板13形成的，但它们会干燥成一个单一的大型矿床，通常大得多的是颗粒尺寸的所希望的范围（相关与这个工作RDX质量）。喷墨RDX粒子标准在这项工作中使用定量提取和分析程序沿着演示用于确定擦拭收集效率的方法。这些测量旨在促进新采样的发展提供更好的收集效率湿巾，并支持在现场取样的最佳做法，包括靶向产生更多的样本，适当用力收集过程中使用的表面，以及该地区之前的分析覆盖。

<table border="0" cellpadding="0" cellspacing="0" width="624">
	<tbody>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Slip/Peel Tester</td>
			<td style="width:123px;">Imass</td>
			<td style="width:119px;">TL-2300</td>
			<td style="width:167px;">replaces TL-2200 used in protocol</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">3D printer</td>
			<td style="width:123px;">Stratasys</td>
			<td style="width:119px;">Connex500</td>
			<td>VeroWhite resin as printing material</td>
		</tr>
		<tr height="30">
			<td height="30" style="height:30px;width:216px;">steel rod with thread</td>
			<td style="width:123px;">McMaster-Carr</td>
			<td style="width:119px;">7786T14</td>
			<td>cut to size for desired weight, multiple online vendors available</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">felt or rubber</td>
			<td style="width:123px;"></td>
			<td style="width:119px;"></td>
			<td>backing material in wipe holder, multiple online vendors available</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">PTFE substrate</td>
			<td style="width:123px;">SPI Supplies</td>
			<td style="width:119px;">01426-AB</td>
			<td>1&#34; wide Bytac Bench and Shelf protector, Al-backed, cut to size</td>
		</tr>
		<tr height="84">
			<td height="84" style="height:84px;width:216px;">RDX solution</td>
			<td style="width:123px;">Cerilliant Analytical Reference Standards</td>
			<td style="width:119px;">ERR-001S</td>
			<td>1000 mg/mL in acetonitrile</td>
		</tr>
		<tr height="63">
			<td height="63" style="height:63px;width:216px;">Inkjet printer</td>
			<td style="width:123px;">MicroFab Technologies, Inc.</td>
			<td style="width:119px;">jetlab4 xl-B</td>
			<td></td>
		</tr>
		<tr height="63">
			<td height="63" style="height:63px;width:216px;">Isotopically tagged RDX</td>
			<td style="width:123px;">Cambridge Isotope Laboratories</td>
			<td style="width:119px;">CLM-3846-S</td>
			<td>For internal analytical standard</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">2 mL glass vial</td>
			<td style="width:123px;">Restek</td>
			<td style="width:119px;">21140 /24670</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Methanol</td>
			<td style="width:123px;">Sigma Aldrich</td>
			<td align="right" style="width:119px;">14262</td>
			<td>Chromasolv grade</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">ETD wipe 1</td>
			<td style="width:123px;">DSA Detection</td>
			<td style="width:119px;">DSW8055P</td>
			<td>Ionscan 500 DT wipe</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">ETD wipe 2</td>
			<td style="width:123px;">DSA Detection</td>
			<td style="width:119px;">ST1318P</td>
			<td>Itemiser DX wipe</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:216px;">Ballistic nylon fabric</td>
			<td style="width:123px;">Seattle Fabrics</td>
			<td style="width:119px;">1050 Denier Ballistics</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Synthetic leather fabric</td>
			<td style="width:123px;"></td>
			<td style="width:119px;"></td>
			<td>contact authors for sample</td>
		</tr>
	</tbody>
</table>

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.

这个协议的精确从各种各样的可能的测试表面测量收集效率的能力依赖于样本和它的限制，以在表面上的特定区域的物理特性。如果样品是所定义的区域之外，它可能无法完全擦除采样过程中遇到，并且收集效率将人为地降低。此外，如果颗粒与预期中的微量残留炸药实粒子显著不同，收集效率的测量可能不具有代表性。出于这些原因，我们建议使用这已被证明产生适当的粒度特性，并转移到一个限定的区域与协议一致的内表面测试样品的特定类型的。直接溶液沉积以形成颗粒取决于表面的质地和组合物，并且可以不导致representative样本。 结果在表1中给出对于给定的7.5N的力，并测试表面代表行李的（弹道尼龙机织织物）商业ETD擦拭物1（间位芳族聚酰胺聚合物），对于两个不同的行进距离。所有实验中的移动速度为50毫米/秒，和收集过程中的温度和相对湿度分别为20±2℃和40±4％RH，。结果表明，较长的路径长度导致降低的收集效率，预计由于颗粒10的再沉积。所述36厘米行驶距离，通过使用三个单独的道次表面上，起重在每个路径的端部的擦拭和平移表面以暴露出新鲜的采样路径来实现。延伸的行进距离的这种方法需要抹被提升并多次向下放置，并与连续的可产生不同的结果<html>样本路径。在筛选的方案，很可能是在擦拭被提升并在项目更换很多次，所以这种方法为延长行驶距离是合适的。 从PTFE基板的RDX沉积物的TE的高，如预期的该表面。因为转座因子是接近100％，并且有由基底（步骤3.2.3）的目视检查提供质量保证，TE的测量可以在不影响显著此测试面的CE结果被消除。其他测试表面可具有低或多个可变的TE。在CE的不确定性预期根据我们的经验，迄今这种技术的范围内。第二商业ETD擦拭（PTFE涂覆的编织的玻璃纤维）通常具有比间位芳族聚酰胺聚合物的不确定性擦拭下，尽管它也有在一般（ 图4）下的CE。我们以前用的聚苯乙烯微球工作<html>相比与擦拭物1 F"&gt; 8是具有用于ETD所观察到的低收集效率一致的擦拭2。 <img alt="图1" src="/files/ftp_upload/55484/55484fig1.jpg" /> 图1. 原理图擦拭采样装置（左和中间）与模板测试表面（右）上的样品放置。擦拭收集区域，30毫米直径的圆，的覆盖区被示出在采样路径的开始和结束。擦巾放置在测试表面上，直接行进通过样本位置（一般为5毫米×5mm或更小），并在表面上结束。的行驶距离是从C，所述样品的位置，到最后。 <a href="http://ecsource.jove.com/files/ftp_upload/55484/55484fig1large.jpg" target="_blank">请点击此处查看该图的放大版本。</a> PLOAD / 55484 / 55484fig2.jpg" /&gt; 图2. 示例擦拭支架。自定义保持器组成部件示于左上角的，并且包括三维打印产生的两个塑料部件。这两个组件用来夹住的地方擦拭，并通过两个翼形螺丝固定在一起。可附接的不锈钢砝码是实心杆，在其一端附接至保持器的螺纹螺柱。吊环螺栓是用于约束线的附接。 <img alt="图3" src="/files/ftp_upload/55484/55484fig3.jpg" /> 图3. 设备的配置。黄色纸模板由通过10cm至适合10cm的正方形钢测试的表面上，用于采样路径的切口。与模板中的表面被放置在可移动的平面和调整，直到约束线被拉紧并居中于采样路径。该模板用于配置日È设备和传送测试样品时，但不到位时擦拭采样。 <a href="http://ecsource.jove.com/files/ftp_upload/55484/55484fig3large.jpg" target="_blank">请点击此处查看该图的放大版本。</a> <img alt="图4" src="/files/ftp_upload/55484/55484fig4.jpg" /> 图4. 结果合成皮革试验表面和36厘米行驶距离，通过使用3次的每组12厘米，对于两个不同的擦拭物实现。在CE不确定性给定为1个标准差。 <table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always"><tbody><tr><td> 行驶距离（cm） </td><td> 力（N） </td><td> TE（％） </td><td> RSD（％） </td><td> CE（％） </td><td> RSD（％） </td><td> ñ </td></tR&gt; <tr><td> 36 * </td><td> 7.5 </td><td> 97.4±2.1 </td><td> 2.2 </td><td> 11.7±4.0 </td><td> 34.0 </td><td> 9 </td></tr><tr><td> 12 </td><td> 7.5 </td><td> 98.5±1.3 </td><td> 1.3 </td><td> 22.6±3.4 </td><td> 15.2 </td><td> 4 </td></tr><tr><td colspan="7"> *的每个12厘米3遍。 </td></tr></tbody></table> 表1 的结果为商业ETD擦拭物1个编织尼龙织物测试表面为两个不同的行进距离。在TE和CE不确定性给定为1个标准差。

Watch this Scientific Journal Video about Standardized Method for Measuring Collection Efficiency from Wipe-sampling of Trace Explosives at JoVE.com

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

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 ...

standardized-method-for-measuring-collection-efficiency-from-wipe

Research

JoVE Journal

Engineering

9.4K 次观看.  National Institute of Standards and Technology. 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.

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

Measuring Spatially- and Directionally-varying Light Scattering from Biological Material

Light interacts with an organism's integument on a variety of spatial scales. For example in an iridescent bird: nano-scale structures produce color; the milli-scale structure of barbs and barbules largely determines the directional pattern of reflected light; and through the macro-scale spatial structure of overlapping, curved feathers, these directional effects create the visual texture. Milli-scale and macro-scale effects determine where on the organism's body, and from what viewpoints and under what illumination, the iridescent colors are seen. Thus, the highly directional flash of brilliant color from the iridescent throat of a hummingbird is inadequately explained by its nano-scale structure alone and questions remain. From a given observation point, which milli-scale elements of the feather are oriented to reflect strongly? Do some species produce broader "windows" for observation of iridescence than others? These and similar questions may be asked about any organisms that have evolved a particular surface appearance for signaling, camouflage, or other reasons.
In order to study the directional patterns of light scattering from feathers, and their relationship to the bird's milli-scale morphology, we developed a protocol for measuring light scattered from biological materials using many high-resolution photographs taken with varying illumination and viewing directions. Since we measure scattered light as a function of direction, we can observe the characteristic features in the directional distribution of light scattered from that particular feather, and because barbs and barbules are resolved in our images, we can clearly attribute the directional features to these different milli-scale structures. Keeping the specimen intact preserves the gross-scale scattering behavior seen in nature. The method described here presents a generalized protocol for analyzing spatially- and directionally-varying light scattering from complex biological materials at multiple structural scales.

We present a non-destructive method for sampling spatial variation in the direction of light scattered from structurally complex materials. By keeping the material intact, we preserve gross-scale scattering behavior, while concurrently capturing fine-scale directional contributions with high-resolution imaging. Results are visualized in software at biologically-relevant positions and scales.

从生物材料空间定向变化的光散射测量

Light interacts with an organism's integument on a variety of spatial scales. For example in an iridescent bird: nano-scale structures produce color; the ...

科研

工程学

Measuring Material Microstructure Under Flow Using 1-2 Plane Flow-Small Angle Neutron Scattering

A new small-angle neutron scattering (SANS) sample environment optimized for studying the microstructure of complex fluids under simple shear flow is presented. The SANS shear cell consists of a concentric cylinder Couette geometry that is sealed and rotating about a horizontal axis so that the vorticity direction of the flow field is aligned with the neutron beam enabling scattering from the 1-2 plane of shear (velocity-velocity gradient, respectively). This approach is an advance over previous shear cell sample environments as there is a strong coupling between the bulk rheology and microstructural features in the 1-2 plane of shear. Flow-instabilities, such as shear banding, can also be studied by spatially resolved measurements. This is accomplished in this sample environment by using a narrow aperture for the neutron beam and scanning along the velocity gradient direction. Time resolved experiments, such as flow start-ups and large amplitude oscillatory shear flow are also possible by synchronization of the shear motion and time-resolved detection of scattered neutrons. Representative results using the methods outlined here demonstrate the useful nature of spatial resolution for measuring the microstructure of a wormlike micelle solution that exhibits shear banding, a phenomenon that can only be investigated by resolving the structure along the velocity gradient direction. Finally, potential improvements to the current design are discussed along with suggestions for supplementary experiments as motivation for future experiments on a broad range of complex fluids in a variety of shear motions.

A shear cell is developed for small-angle neutron scattering measurements in the velocity-velocity gradient plane of shear and is used to characterize complex fluids. Spatially resolved measurements in the velocity gradient direction are possible for studying shear-banding materials. Applications include investigations of colloidal dispersions, polymer solutions, and self-assembled structures.

测量材料在微流使用1-2面流小角中子散射

A new small-angle neutron scattering (SANS) sample environment optimized for studying the microstructure of complex fluids under simple shear flow is ...

The Preparation of Electrohydrodynamic Bridges from Polar Dielectric Liquids

Horizontal and vertical liquid bridges are simple and powerful tools for exploring the interaction of high intensity electric fields (8-20 kV/cm) and polar dielectric liquids. These bridges are unique from capillary bridges in that they exhibit extensibility beyond a few millimeters, have complex bi-directional mass transfer patterns, and emit non-Planck infrared radiation. A number of common solvents can form such bridges as well as low conductivity solutions and colloidal suspensions. The macroscopic behavior is governed by electrohydrodynamics and provides a means of studying fluid flow phenomena without the presence of rigid walls. Prior to the onset of a liquid bridge several important phenomena can be observed including advancing meniscus height (electrowetting), bulk fluid circulation (the Sumoto effect), and the ejection of charged droplets (electrospray). The interaction between surface, polarization, and displacement forces can be directly examined by varying applied voltage and bridge length. The electric field, assisted by gravity, stabilizes the liquid bridge against Rayleigh-Plateau instabilities. Construction of basic apparatus for both vertical and horizontal orientation along with operational examples, including thermographic images, for three liquids (e.g., water, DMSO, and glycerol) is presented.

Horizontal and vertical electrohydrodynamic liquid bridges are simple and powerful tools for exploring the interaction of high intensity electric fields and polar dielectric liquids. The construction of basic apparatus and operational examples, including thermographic images, for three liquids (e.g., water, DMSO, and glycerol) is presented.

高压直流电桥从极地介电液的制备

Horizontal and vertical liquid bridges are simple and powerful tools for exploring the interaction of high intensity electric fields (8-20 kV/cm) and ...

Making Record-efficiency SnS Solar Cells by Thermal Evaporation and Atomic Layer Deposition

Tin sulfide (SnS) is a candidate absorber material for Earth-abundant, non-toxic solar cells. SnS offers easy phase control and rapid growth by congruent thermal evaporation, and it absorbs visible light strongly. However, for a long time the record power conversion efficiency of SnS solar cells remained below 2%. Recently we demonstrated new certified record efficiencies of 4.36% using SnS deposited by atomic layer deposition, and 3.88% using thermal evaporation. Here the fabrication procedure for these record solar cells is described, and the statistical distribution of the fabrication process is reported. The standard deviation of efficiency measured on a single substrate is typically over 0.5%. All steps including substrate selection and cleaning, Mo sputtering for the rear contact (cathode), SnS deposition, annealing, surface passivation, Zn(O,S) buffer layer selection and deposition, transparent conductor (anode) deposition, and metallization are described. On each substrate we fabricate 11 individual devices, each with active area 0.25 cm2. Further, a system for high throughput measurements of current-voltage curves under simulated solar light, and external quantum efficiency measurement with variable light bias is described. With this system we are able to measure full data sets on all 11 devices in an automated manner and in minimal time. These results illustrate the value of studying large sample sets, rather than focusing narrowly on the highest performing devices. Large data sets help us to distinguish and remedy individual loss mechanisms affecting our devices.

Tin sulfide (SnS) is a candidate material for Earth-abundant, non-toxic solar cells. Here, we demonstrate the fabrication procedure of the SnS solar cells employing atomic layer deposition, which yields 4.36% certified power conversion efficiency, and thermal evaporation which yields 3.88%.

通过热蒸发和原子层沉积使记录效率的SnS太阳能电池

Tin sulfide (SnS) is a candidate absorber material for Earth-abundant, non-toxic solar cells. SnS offers easy phase control and rapid growth by congruent ...

Research and Development of High-performance Explosives

Developmental testing of high explosives for military applications involves small-scale formulation, safety testing, and finally detonation performance tests to verify theoretical calculations. For newly developed formulations, the process begins with small-scale mixes, thermal testing, and impact and friction sensitivity. Only then do subsequent larger scale formulations proceed to detonation testing, which will be covered in this paper. Recent advances in characterization techniques have led to unparalleled precision in the characterization of early-time evolution of detonations. The new technique of Photonic Doppler Velocimetry (PDV) for the measurement of detonation pressure will be shared and compared with traditional fiber-optic detonation velocity and plate-dent calculation of detonation pressure. In particular, the role of aluminum in explosive formulations will be discussed. Recent developments led to the development of explosive formulations that result in reaction of aluminum very early in the detonation product expansion. This enhanced reaction leads to changes in the detonation velocity and pressure due to reaction of the aluminum with oxygen in the expanding gas products.

Developmental testing of high explosives for military applications involves small-scale formulation, safety testing, and finally detonation performance tests to verify theoretical calculations. This paper will share typical development tests associated with the measurement of detonation velocity and detonation pressure.

高性能炸药的研究与发展

Developmental testing of high explosives for military applications involves small-scale formulation, safety testing, and finally detonation performance ...

Methods for Measuring the Orientation and Rotation Rate of 3D-printed Particles in Turbulence

Experimental methods are presented for measuring the rotational and translational motion of anisotropic particles in turbulent fluid flows. 3D printing technology is used to fabricate particles with slender arms connected at a common center. Shapes explored are crosses (two perpendicular rods), jacks (three perpendicular rods), triads (three rods in triangular planar symmetry), and tetrads (four arms in tetrahedral symmetry). Methods for producing on the order of 10,000 fluorescently dyed particles are described. Time-resolved measurements of their orientation and solid-body rotation rate are obtained from four synchronized videos of their motion in a turbulent flow between oscillating grids with R&#955; = 91. In this relatively low-Reynolds number flow, the advected particles are small enough that they approximate ellipsoidal tracer particles. We present results of time-resolved 3D trajectories of position and orientation of the particles as well as measurements of their rotation rates.

We use 3D printing to fabricate anisotropic particles in the shapes of jacks, crosses, tetrads, and triads, whose alignments and rotations in turbulent fluid flow can be measured from multiple simultaneous video images.

测量的方向和旋转速率方法3D打印在湍流颗粒

Experimental methods are presented for measuring the rotational and translational motion of anisotropic particles in turbulent fluid flows. 3D printing ...

Measuring Spray Droplet Size from Agricultural Nozzles Using Laser Diffraction

When making an application of any crop protection material such as an herbicide or pesticide, the applicator uses a variety of skills and information to make an application so that the material reaches the target site (i.e., plant). Information critical in this process is the droplet size that a particular spray nozzle, spray pressure, and spray solution combination generates, as droplet size greatly influences product efficacy and how the spray moves through the environment. Researchers and product manufacturers commonly use laser diffraction equipment to measure the spray droplet size in laboratory wind tunnels. The work presented here describes methods used in making spray droplet size measurements with laser diffraction equipment for both ground and aerial application scenarios that can be used to ensure inter- and intra-laboratory precision while minimizing sampling bias associated with laser diffraction systems. Maintaining critical measurement distances and concurrent airflow throughout the testing process is key to this precision. Real time data quality analysis is also critical to preventing excess variation in the data or extraneous inclusion of erroneous data. Some limitations of this method include atypical spray nozzles, spray solutions or application conditions that result in spray streams that do not fully atomize within the measurement distances discussed. Successful adaption of this method can provide a highly efficient method for evaluation of the performance of agrochemical spray application nozzles under a variety of operational settings. Also discussed are potential experimental design considerations that can be included to enhance functionality of the data collected.

We present protocols to be used in the measurement of spray droplet size from agricultural nozzles used in both aerial and ground based agrochemical applications. These methods presented were developed to provide consistent and repeatable droplet size data both inter- and intra-laboratory, when using laser diffraction systems.

从农业喷嘴采用激光衍射测量喷雾的雾滴尺寸

When making an application of any crop protection material such as an herbicide or pesticide, the applicator uses a variety of skills and information to ...

A Novel Method for In Situ Electromechanical Characterization of Nanoscale Specimens

Electrically assisted deformation (EAD) is increasingly being used to improve the formability of metals during processes such as sheet metal rolling and forging. Adoption of this technique is proceeding despite disagreement concerning the underlying mechanism responsible for EAD. The experimental procedure described herein enables a more explicit study compared to previous EAD research by removing thermal effects, which are responsible for disagreement in interpreting previous EAD results. Furthermore, as the procedure described here enables EAD observation in situ and in real time in a transmission electron microscope (TEM), it is superior to existing post-mortem methods that observe EAD effects post-test. Test samples consist of a single crystal copper (SCC) foil having a free-standing tensile test section of nanoscale thickness, fabricated using a combination of laser and ion beam milling. The SCC is mounted to an etched silicon base that provides mechanical support and electrical isolation while serving as a heat sink. Using this geometry, even at high current density (~3,500 A/mm2), the test section experiences a negligible temperature increase (&#60;0.02 &#176;C), thus eliminating Joule heating effects. Monitoring material deformation and identifying the corresponding changes to microstructures, e.g. dislocations, are accomplished by acquiring and analyzing a series of TEM images. Our sample preparation and in situ experiment procedures are robust and versatile as they can be readily utilized to test materials with different microstructures, e.g., single and polycrystalline copper.

A Novel Method for In Situ Electromechanical Characterization of Nanoscale Specimens

Isolating electrical and thermal effects on electrically assisted deformation (EAD) is very difficult using macroscopic samples. Metallic sample micro- and nanostructures together with a custom test procedure have been developed to evaluate the impact of applied current on the formation without joule heating and evolution of dislocations on these samples.

一种新的方法<em&gt;原位</em&gt;纳米级样品的机电表征

Electrically assisted deformation (EAD) is increasingly being used to improve the formability of metals during processes such as sheet metal rolling and ...

Indoor Experimental Assessment of the Efficiency and Irradiance Spot of the Achromatic Doublet on Glass (ADG) Fresnel Lens for Concentrating Photovoltaics

We present a method to characterize achromatic Fresnel lenses for photovoltaic applications. The achromatic doublet on glass (ADG) Fresnel lens is composed of two materials, a plastic and an elastomer, whose dispersion characteristics (refractive index variation with wavelength) are different. We first designed the lens geometry and then used ray-tracing simulation, based on the Monte Carlo method, to analyze its performance from the point of view of both optical efficiency and the maximum attainable concentration. Afterwards, ADG Fresnel lens prototypes were manufactured using a simple and reliable method. It consists of a prior injection of plastic parts and a consecutive lamination, together with the elastomer and a glass substrate to fabricate the parquet of ADG Fresnel lenses. The accuracy of the manufactured lens profile is examined using an optical microscope while its optical performance is evaluated using a solar simulator for concentrator photovoltaic systems. The simulator is composed of a xenon flash lamp whose emitted light is reflected by a parabolic mirror. The collimated light has a spectral distribution and an angular aperture similar to the real Sun. We were able to assess the optical performance of the ADG Fresnel lenses by taking photographs of the irradiance spot cast by the lens using a charge-coupled device (CCD) camera and measuring the photocurrent generated by several types of multi junction (MJ) solar cells, which have been previously characterized at a solar simulator for concentrator solar cells. These measurements have demonstrated the achromatic behavior of ADG Fresnel lenses and, as a consequence, the suitability of the modelling and manufacturing methods.

Indoor Experimental Assessment of the Efficiency and Irradiance Spot of the Achromatic Doublet on Glass ADG Fresnel Lens for Concentrating Photovoltaics

The achromatic doublet on glass (ADG) Fresnel lens makes use of two materials with differing dispersion to reduce chromatic aberration and increase attainable concentration. In this paper, a protocol for the complete characterization of the ADG Fresnel lens is presented.

玻璃 (ADG) 菲涅耳透镜对聚光光伏的效率和辐照点的室内实验评价

We present a method to characterize achromatic Fresnel lenses for photovoltaic applications. The achromatic doublet on glass (ADG) Fresnel lens is ...

Experimental Procedure for Laboratory Studies of In Situ Burning : Flammability and Burning Efficiency of Crude Oil

A new method for the simultaneous study of the flammability and burning efficiency of fresh and weathered crude oil through two experimental laboratory setups is presented. The experiments are easily repeatable compared to operational scale experiments (pool diameter &#8805;2 m), while still featuring quite realistic in situ burning conditions of crude oil on water. Experimental conditions include a flowing water sub-layer that cools the oil slick and an external heat flux (up to 50 kW/m2) that simulates the higher heat feedback to the fuel surface in operational scale crude oil pool fires. These conditions enable a controlled laboratory study of the burning efficiency of crude oil pool fires that are equivalent to operational scale experiments. The method also provides quantitative data on the requirements for igniting crude oils in terms of the critical heat flux, ignition delay time as a function of the incident heat flux, the surface temperature upon ignition, and the thermal inertia. This type of data can be used to determine the required strength and duration of an ignition source to ignite a certain type of fresh or weathered crude oil. The main limitation of the method is that the cooling effect of the flowing water sub-layer on the burning crude oil as a function of the external heat flux has not been fully quantified. Experimental results clearly showed that the flowing water sub-layer does improve how representative this setup is of in situ burning conditions, but to what extent this representation is accurate is currently uncertain. The method nevertheless features the most realistic in situ burning laboratory conditions currently available for simultaneously studying the flammability and burning efficiency of crude oil on water.

Experimental Procedure for Laboratory Studies of In Situ Burning : Flammability and Burning Efficiency of Crude Oil

Here, we present a protocol to simultaneously study the flammability and burning efficiency of fresh and weathered crude oil under conditions that simulate in situ burning operations on the sea.

原位燃烧试验方法: 原油可燃性和燃烧效率

A new method for the simultaneous study of the flammability and burning efficiency of fresh and weathered crude oil through two experimental laboratory ...