作者感谢命运加西亚，小威费拉罗，埃里克·基罗斯和史蒂芬克恩（先进复合材料研究，工程和科学实验室），他们在设计和制造测试设置的帮助。肖恩·马龙，迈克尔·Akahori，大卫Kehlet（工程实验室制造）的承认了他们的建议，并在加工过程中的协助。支持美国国家科学基金会（协作补助CMMI-1265691和欧洲区域办事处的补充）和海军研究办公室（N00014-13-1-0604至A. Muliana，德州＆M大学（首席研究员）和V.拉萨波纳拉由项目总监拉贾帕克萨亚帕管理）的衷心赞赏。

1.装入标本<ol><li>提高罐的盖子并在侧部支撑搁（ 图4）。 </li><li>放置在U形螺栓的试验片，并确保横杆正在试样的中心接触。 </li><li>搁置在铝支撑悬挂在盖的检体的端部。样品的端部应具有5-10毫米的突出端。 </li><li>重复步骤1.2-1.4对所有将被测试的标本。 </li><li>取下盖子支持，下盖，并确保盖子落座于该储箱的唇。 </li><li>通过将权重应用到钢杆旁边的外滑轮应用所需的力。 </li></ol> 2.测量位移<ol><li>确保字符串电位线拉紧。 </li><li>使用数字万用表，测量电阻两端的电位的外销（ 图3）中，用黑色至引脚1和红至引脚3，并记录读数。 </li><li>转换电阻读入的位移读取通过计算校准因子（在这种情况下，1kΩ的对应一个64.895毫米位移）。 </li><li>重复步骤2.1-2.3为每个标本。 </li></ol> 3.权衡标本<ol><li>在开始称量过程中，记录位移数据和编制临时收容室充满在室温测试液，按ASTM D5229 31或相应的检测标准。 </li><li>从钢索的端部取出开槽权重。 </li><li>提高罐的盖子并在侧部支撑休息吧。 </li><li>取下样品，将其放入准备好的临时收容室。重复所有样品的这一步。 </li><li>取出试样并干燥它们单独使用微纤维布，以除去多余的液体。 </li><li>放置在试样上的高精确度的规模和记录数据Reading。 </li><li>重复步骤3.5-3.6为所有标本，然后按照协议第1步 。 </li></ol>

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The authors have nothing to disclose.

从所获得的数据，可以看出，并发测试场景并影响闭孔聚氨酯泡沫试样的耐久性。这可以通过在显著不同的位移（ 图5）和残余的负载比较失败干湿标本（ 图6）可以看出， 图7示出了样品的残余强度试验后的照片。还应当指出的是，虽然干标本的位移的24小时观测间隔内达到稳定状态，这些湿标本没有。因此，未来的测试将在较长的时间间隔进行，要么实现?...

聚合物和纤维增强聚合物（FRP）复合材料已通过各种工程结构，从飞机和飞船，舰艇，民用基础设施，（见Katnam 等 1，Hollaway 2，Mouritz 等人的例子评论第3号 ），汽车和火车，风力涡轮机叶片，以假肢和生物材料缝合线和植入物。这些材料的耐久性受复杂的服务方案，其可包括的组合）的热机械载荷， 例如 ，冷冻-解冻循环在民用基础设施4，亚音速/超音速飞行型材5穿在金属背聚乙烯6） ;二）的降解，由于环境和化学制剂， 例如 ，海水，除冰，用于航空航天和海军结构7-10中，聚甲基丙烯酸甲酯的牙科复合材料由于唾液降解11的液压流体;三）复杂的INTE材料在紧固或接合接头，异种材料之间例如 ，电偶腐蚀和剥离，ractions是否在碳/纤维补片修补在飞行器铝皮，或碳/ PEEK骨板由不锈钢12紧固。 有不幸的是有限的并发在职刺激对这些材料的长期耐久性的影响的知识。大多数聚合物可以被分类为粘弹性材料。机械载荷和环境条件显著影响聚合物的粘弹性响应。因此，可靠的模型，这些材料的长期行为应该能够把依赖于时间的响应耦合湿热，机械，化学刺激。反过来，这将提高设计的预测，安全性和基于状态的维护/更换协议。 有实验测试在湿热作用的大型文献体例如湿热扩散试验:如果样品的尺度允许，该材料的样品可以被定位在所希望的湿度和温度水平的腔室。将样品定期取出，以测量的时间在给定量的质量和/或体积的变化，从周向年10,13-17。在湿热试验之后可以机械测试， 即 ，剩余静/疲劳强度/断裂力学测试17-19，其中仅提供了有关湿热刺激对材料的机械反应的影响的信息。测试数据可以装配不同的复杂性，从简单的菲克扩散模型，包括依赖于浓度，压力，温度，可逆物理老化/增塑和不可逆的化学反应的扩散模型。这个实验的输出可以在结构分析得到进一步整合。 很少有作家已经解决了同时HY的影响grothermal和机械刺激。在这些研究的FRP复合材料，诺依曼和Garom 20浸入强调和无应力样本在蒸馏水中。应力被通过定位压缩不锈钢弹簧内的试样施加，通过使用不同的弹簧刚度和压缩载荷调整负载。类似的过程被报道万等人 21。何浦林和Karbhari 22所采用的弯曲夹具环境室用于不同的相对湿度的百分比（相对湿度％）和温度水平内。所述预调节样品进行到给定的弯曲应变的水平，对应于静态极限拉伸应变为该复合物的百分比。 Kasturiarachchi和普里查德23制备一个不锈钢4点弯曲夹具（每个试样1），将其放置在一个架子上的一个大的玻璃干燥器。干燥器被部分地填充有蒸馏水，不得不小的泄漏，防止BUildup的压力，并放置在湿度室中于95％相对湿度。盖勒特和特里7查处海洋级玻璃钢复合标本进行联合下蠕变负荷和100％RH其耐用性。他们的样品被装在四点弯曲以恒定载荷等于失败静态挠曲负荷的20％，而完全浸没在海水中。蠕变挠度是通过使用光束在中央的横截面，并在玻璃板的外表面之间的厚度计周期性地获得（据推断，这种测量是在室的外部执行）。阿卜杜勒-马吉德等人 24放置的玻璃/环氧样品其经NASA兰利提供，如被装在沿纤维方向张力的标本，在最终的轴向负荷为20％的殷钢环境夹具。 Ellyin和Rohrbarcher 25跑湿热测试为多达140天，然后测试在疲劳试样的液压试验机上。试样s被包裹在湿干酪布连接到管和供水。伯爵等人 26位的装载和固定在一个大环境室（5.5 立方米 ）的标本。 因为在许多实验研究讨论的，环境条件会影响聚合物&#39;的机械性能和响应。一些有限的实验也表明，机械应力/应变的存在影响的扩散过程中的聚合物。因此，为了促进理解上的下机械和非机械效应的聚合物基材料的整体性能，有必要对并发测试。 有在本文中讨论的测试平台的设计背后的几个目标。首先，该平台是实验装置在不同类型的FRP夹层复合材料的风力涡轮机的hygrothermo力学行为的多年研究的一部分第二海军工程应用。试验数据被用来校正在所述粘弹性构方程为聚合物复合材料的参数。本构模型的基础上发展，多年来深受Muliana和合作者27-30工作。第二个目标是为具有低成本和用户友好的测试平台，例如一个可以很容易地重新定位在一个实验室（ 例如 ，以一个尺度为质量测量，或对流体的源， 例如 ，一个未来从水龙头，一个通风柜或易燃柜）。第三个目标是建立一个测试平台，它能够抵抗许多化学品在服务常用的（特别是液压流体，除冰，清洗剂用于航空航天应用8-10），从而标本可浸入这样的化学品，以及其耐用性可以进行评估。 腔室（ 图1），用高密度polyethyle构造NE，它具有高耐化学性。如上所述，预计今后的工作将包括浸在液压流体的复合材料的hygrothermo机械调查，除冰，清洁溶剂。自热调节是测试的一个组成部分，膨胀聚苯乙烯泡沫体适合围绕罐的侧面和固定就位通过带与钢框架本身，以防止与环境进行热交换。 腔室（ 图2）的盖是从透明，9.525毫米厚的聚碳酸酯制，使用户能够在测试过程中观察试样，而不会干扰测试。该盖由铝的T杆，这是加工成下在罐的侧面悬垂括号滑动地固定在适当位置。 弯曲在标本是由三个铝块，其从盖垂下，并且通过盖子槽被紧固颁布。这三个模块允许最多四个Specimens到一次进行测试，而在盖的槽允许根据试样的长度的块的间距进行调整。每块圆在接触边缘直径12.7毫米，在坚持以ASTM标准D790-10。试样被定位下方的两个3块，与施加在其中心以诱导弯曲的向上的力（ 图1-2）。 该装置在设计时最大的多功能性和易用性，使用的初衷。脚轮与41.275毫米直径被紧固的室，用于移动性目的的下方。以上这些，该罐是由与金属丝网底梁和横梁用于支撑一个焊接钢架支撑。角库存衬垫为外槽的角落被制造以保持绝缘层被粉碎的开销重量和位移计（串锅装置，稍后讨论）。在上面，角度的股票再次被用于取景。滑轮和字符串电位系统measu重中跨偏转被安装在4钢，方管拱（ 图3）。该中心两个拱出这四个携带串电位器和可调占样本的多功能性。字符串电位器均采用扭力弹簧构造和电位器（如可伸缩的关键挂链上找到）与三管齐下电子输出。滑轮被对准并安装用于与钢缆从由试样的刚性连接到一个挂杆在腔，用于调节体重的应用的侧运行使用。 的载荷被施加到使用一系列电缆，滑轮，联系和螺栓试样。首先，将试样放入所述U形螺栓，使得10毫米横杆被接触的跨度的中间。一个9.525毫米直径钢杆吊环螺栓的每一端，然后连接到U型螺栓。通过腔室的盖这种钢连接传递。钢索和芳纶吨hread附着到U形螺栓对面有眼螺栓。这允许从字符串电位的芳纶线程从一个刚性点读取数据。钢缆继续向上，并越过两个滑轮，使负载在罐的外周施用。缆线随后连接到一个9.525毫米直径钢杆用作开槽重量衣架。此吊架提供其中开槽权重可在为了应用所需的负荷被设置的地方。

<table border="0" cellpadding="0" cellspacing="0" width="581">
	<tbody>
		<tr height="42">
			<td height="42" style="height:42px;width:127px;">Name of Material/</td>
			<td rowspan="2" style="width:140px;">Company</td>
			<td rowspan="2" style="width:129px;">Catalog Number</td>
			<td rowspan="2" style="width:185px;">Comments/Description</td>
		</tr>
		<tr height="22">
			<td height="22" style="height:22px;width:127px;">Equipment</td>
		</tr>
		<tr height="64">
			<td height="64" style="height:64px;width:127px;">Aluminum 6061 rectangular bars</td>
			<td style="width:140px;">McMaster-Carr, USA</td>
			<td style="width:129px;">8975K268, 1668T72, 7062T17,&#160;</td>
			<td style="width:185px;">Part of testing platform</td>
		</tr>
		<tr height="43">
			<td height="43" style="height:43px;width:127px;">Aluminum 6061 90 deg. angles</td>
			<td style="width:140px;">McMaster-Carr, USA</td>
			<td style="width:129px;">8982K91, 8982K14&#160;</td>
			<td style="width:185px;">Part of testing platform</td>
		</tr>
		<tr height="43">
			<td height="43" style="height:43px;width:127px;">440C stainless steel</td>
			<td style="width:140px;">McMaster-Carr, USA</td>
			<td style="width:129px;">6253K52</td>
			<td style="width:185px;">Part of testing platform</td>
		</tr>
		<tr height="21">
			<td height="43" rowspan="2" style="height:43px;width:127px;">High-density polyethylene sheets</td>
			<td rowspan="2" style="width:140px;">Tap Plastics, USA</td>
			<td rowspan="2" style="width:129px;">N/A (0.236 in. thick x 10.75 in. wide x 16.75 in. long)</td>
			<td rowspan="2" style="width:185px;">Part of testing platform</td>
		</tr>
		<tr height="22">
		</tr>
		<tr height="21">
			<td height="43" rowspan="2" style="height:43px;width:127px;">High-density polyethylene sheets</td>
			<td rowspan="2" style="width:140px;">Tap Plastics, USA</td>
			<td rowspan="2" style="width:129px;">N/A (0.354 in. thick x 6 in. wide x 10 in. long)</td>
			<td rowspan="2" style="width:185px;">Part of testing platform</td>
		</tr>
		<tr height="22">
		</tr>
		<tr height="21">
			<td height="43" rowspan="2" style="height:43px;width:127px;">High-density polyethylene sheets</td>
			<td rowspan="2" style="width:140px;">Tap Plastics, USA</td>
			<td rowspan="2" style="width:129px;">N/A (0.354 in. thick x 6 in. wide x 16.75 in. long)</td>
			<td rowspan="2" style="width:185px;">Part of testing platform</td>
		</tr>
		<tr height="22">
		</tr>
		<tr height="21">
			<td height="43" rowspan="2" style="height:43px;width:127px;">Polycarbonate sheets</td>
			<td rowspan="2" style="width:140px;">Tap Plastics, USA</td>
			<td rowspan="2" style="width:129px;">N/A (0.375 in thick, 11.5 in. wide, 17.5 in long)</td>
			<td rowspan="2" style="width:185px;">Part of testing platform</td>
		</tr>
		<tr height="22">
		</tr>
		<tr height="21">
			<td height="43" rowspan="2" style="height:43px;width:127px;">Expanded polystyrene foam</td>
			<td rowspan="2" style="width:140px;">Home Depot</td>
			<td rowspan="2" style="width:129px;">Model # 310880 Internet # 202532855</td>
			<td rowspan="2" style="width:185px;">Part of testing platform</td>
		</tr>
		<tr height="22">
		</tr>
		<tr height="43">
			<td height="43" style="height:43px;width:127px;">Galvanized steel rope</td>
			<td style="width:140px;">McMaster-Carr, USA</td>
			<td style="width:129px;">3498T63</td>
			<td style="width:185px;">Part of testing platform</td>
		</tr>
		<tr height="43">
			<td height="43" style="height:43px;width:127px;">Steel eye bolt</td>
			<td style="width:140px;">McMaster-Carr, USA</td>
			<td style="width:129px;">3013T341</td>
			<td style="width:185px;">Part of testing platform</td>
		</tr>
		<tr height="21">
			<td height="43" rowspan="2" style="height:43px;width:127px;">Low-carbon steel 90 deg. angle</td>
			<td rowspan="2" style="width:140px;">McMaster-Carr, USA</td>
			<td rowspan="2" style="width:129px;">9017K444&#160;</td>
			<td rowspan="2" style="width:185px;">Part of testing platform</td>
		</tr>
		<tr height="22">
		</tr>
		<tr height="78">
			<td height="100" rowspan="2" style="height:101px;width:127px;">Low-carbon steel rods</td>
			<td rowspan="2" style="width:140px;">McMaster-Carr, USA</td>
			<td rowspan="2" style="width:129px;">8920K84, 8920K75, 8920K231, 8920K135, 8920K84&#160;&#160;&#160;</td>
			<td rowspan="2" style="width:185px;">Part of testing platform</td>
		</tr>
		<tr height="22">
		</tr>
		<tr height="58">
			<td height="80" rowspan="2" style="height:81px;width:127px;">Low-carbon steel tubes</td>
			<td rowspan="2" style="width:140px;">McMaster-Carr, USA</td>
			<td rowspan="2" style="width:129px;">6527K314, 8910K394, 8910K395, 8920K94&#160;&#160;</td>
			<td rowspan="2" style="width:185px;">Part of testing platform</td>
		</tr>
		<tr height="22">
		</tr>
		<tr height="43">
			<td height="43" style="height:43px;width:127px;">304 stainless steel U-bolt</td>
			<td style="width:140px;">McMaster-Carr, USA</td>
			<td style="width:129px;">8896T104</td>
			<td style="width:185px;">Part of testing platform</td>
		</tr>
		<tr height="43">
			<td height="43" style="height:43px;width:127px;">Steel pulley</td>
			<td style="width:140px;">McMaster-Carr, USA</td>
			<td style="width:129px;">3099T34</td>
			<td style="width:185px;">Part of testing platform</td>
		</tr>
		<tr height="43">
			<td height="43" style="height:43px;width:127px;">1008 carbon steel sheets</td>
			<td style="width:140px;">McMaster-Carr, USA</td>
			<td style="width:129px;">9302T113</td>
			<td style="width:185px;">Part of testing platform</td>
		</tr>
		<tr height="43">
			<td height="43" style="height:43px;width:127px;">Light duty swivel casters</td>
			<td style="width:140px;">Harbor Freight, USA</td>
			<td style="width:129px;">41519</td>
			<td style="width:185px;">Part of testing platform</td>
		</tr>
		<tr height="21">
			<td height="43" rowspan="2" style="height:43px;width:127px;">100-lbf Vinyl Weight Set</td>
			<td rowspan="2" style="width:140px;">Overstock.com</td>
			<td rowspan="2" style="width:129px;">11767059</td>
			<td rowspan="2" style="width:185px;">Part of testing platform</td>
		</tr>
		<tr height="22">
		</tr>
		<tr height="64">
			<td height="64" style="height:64px;width:127px;">Closed-cell polyurethane foam</td>
			<td style="width:140px;">General Plastics, USA</td>
			<td style="width:129px;">FR-3704</td>
			<td style="width:185px;">Testing samples</td>
		</tr>
		<tr height="43">
			<td height="43" style="height:43px;width:127px;">Deionized water</td>
			<td style="width:140px;">Faucet, PurLab filtering system</td>
			<td style="width:129px;">N/A</td>
			<td style="width:185px;">Conditioning fluid of tank</td>
		</tr>
		<tr height="43">
			<td height="43" style="height:43px;width:127px;">Torsional spring</td>
			<td style="width:140px;">Retractable Key Clip, Ebay, USA</td>
			<td style="width:129px;">Lot 10</td>
			<td style="width:185px;">Used to build string potentiometer</td>
		</tr>
		<tr height="43">
			<td height="43" style="height:43px;width:127px;">Kevlar thread</td>
			<td style="width:140px;">Cabela&#8217;s</td>
			<td style="width:129px;">IK-321909</td>
			<td style="width:185px;">Used to build string potentiometer</td>
		</tr>
		<tr height="43">
			<td height="43" style="height:43px;width:127px;">10 kOhm potentiometer</td>
			<td style="width:140px;">Ebay, USA</td>
			<td style="width:129px;">3590S-2-103L</td>
			<td style="width:185px;">Used to build string potentiometer</td>
		</tr>
		<tr height="64">
			<td height="64" style="height:64px;width:127px;">Digital multimeter</td>
			<td style="width:140px;">Harbor Freight, USA</td>
			<td style="width:129px;">98674</td>
			<td style="width:185px;">Used to take resistance measurements of string potentiometer</td>
		</tr>
	</tbody>
</table>

a testing platform for durability studies of polymers and fiber-reinforced polymer composites under concurrent hygrothermo-mechanical stimuli

服务条件下的聚合物和纤维增强聚合物复合材料的耐用性是其强大的设计和基于状态的维护需要解决的一个重要方面。这些材料是通过在一个宽范围的工程应用中，从飞机和船舶的结构，对桥梁，风力涡轮机叶片，生物材料和生物医学植入物。聚合物是粘弹性材料，并且它们的响应可以是高度非线性的，从而使之具有挑战性，预测和监测其使用性能。该实验室规模的试验平台，此呈现助攻并发的机械负荷和对这些材料的环境条件的影响的调查。该平台被设计成低成本和用户友好。其耐化学腐蚀的材料，使该平台适用于化学降解由于在职接触液体的研究。实验的一个例子在RT上的闭孔聚氨酯进行泡沫样品装载有对应于它们的最后的静态和干负荷〜50％的重量。结果表明，该检测装置是适合于这些研究。结果也显示并发载荷下，聚合物的较大的脆弱性，基于所述更高的中点位移和较低的残余破坏载荷。建议向测试设备的额外改进而成。

测试仪器已成功举办标本浸在液体下三点弯曲。以合理的精度，标本可以加载并使用从电位为中点挠度变化准确读数测试。的电阻的变化可以被记录到4显著数字，导致0.1微米量级的位移分辨率。 Hygrothermo机械试验在RT上两组四个试样的闭孔聚氨酯泡沫塑料进行的，用标称尺寸215毫米长度×24毫米宽×18毫米的厚度。一组是在干燥条件下）中的空气腔室，目的是作为试验，油箱内...

Watch this Scientific Journal Video about A Testing Platform for Durability Studies of Polymers and Fiber-reinforced Polymer Composites under Concurrent Hygrothermo-mechanical Stimuli at JoVE.com

A Testing Platform for Durability Studies of Polymers and Fiber-reinforced Polymer Composites under Concurrent Hygrothermo-mechanical Stimuli

The durability of polymers and fiber-reinforced polymer composites in service is a critical aspect for their designs and condition-based maintenance. We present a novel low-cost laboratory testing platform for the investigation of the influence of concurrent mechanical and environmental loadings, and may help design more efficient yet safer composite structures.

一个测试平台为聚合物的耐久性研究，并在同期Hygrothermo机械刺激纤维增强聚合物复合材料

The durability of polymers and fiber-reinforced polymer composites under service condition is a critical aspect to be addressed for their robust designs ...

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13.7K 次观看.  University of California, Davis. The durability of polymers and fiber-reinforced polymer composites in service is a critical aspect for their designs and condition-based maintenance. We present a novel low-cost laboratory testing platform for the investigation of the influence of concurrent mechanical and environmental loadings, and may help design more efficient yet safer composite structures.

视频: A Testing Platform for Durability Studies of Polymers and Fiber-reinforced Polymer Composites under Concurrent Hygrothermo-mechanical Stimuli

Controlling the Size, Shape and Stability of Supramolecular Polymers in Water

For aqueous based supramolecular polymers, the simultaneous control over shape, size and stability is very difficult1. At the same time, the ability to do so is highly important in view of a number of applications in functional soft matter including electronics, biomedical engineering, and sensors. In the past, successful strategies to control the size and shape of supramolecular polymers typically focused on the use of templates2,3, end cappers4 or selective solvent techniques5. 
Here we disclose a strategy based on self-assembling discotic amphiphiles that leads to the control over stack length and shape of ordered, chiral columnar aggregates. By balancing electrostatic repulsive interactions on the hydrophilic rim and attractive non-covalent forces within the hydrophobic core of the polymerizing building block, we manage to create small and discrete spherical objects6,7. Increasing the salt concentration to screen the charges induces a sphere-to-rod transition. Intriguingly, this transition is expressed in an increase of cooperativity in the temperature-dependent self-assembly mechanism, and more stable aggregates are obtained. 
For our study we select a benzene-1,3,5-tricarboxamide (BTA) core connected to a hydrophilic metal chelate via a hydrophobic, fluorinated L-phenylalanine based spacer (Scheme 1). The metal chelate selected is a Gd(III)-DTPA complex that contains two overall remaining charges per complex and necessarily two counter ions. The one-dimensional growth of the aggregate is directed by &pi;-&pi; stacking and intermolecular hydrogen bonding. However, the electrostatic, repulsive forces that arise from the charges on the Gd(III)-DTPA complex start limiting the one-dimensional growth of the BTA-based discotic once a certain size is reached. At millimolar concentrations the formed aggregate has a spherical shape and a diameter of around 5 nm as inferred from 1H-NMR spectroscopy, small angle X-ray scattering, and cryogenic transmission electron microscopy (cryo-TEM). The strength of the electrostatic repulsive interactions between molecules can be reduced by increasing the salt concentration of the buffered solutions. This screening of the charges induces a transition from spherical aggregates into elongated rods with a length &gt; 25 nm. Cryo-TEM allows to visualise the changes in shape and size. In addition, CD spectroscopy permits to derive the mechanistic details of the self-assembly processes before and after the addition of salt. Importantly, the cooperativity -a key feature that dictates the physical properties of the produced supramolecular polymers- increases dramatically upon screening the electrostatic interactions. This increase in cooperativity results in a significant increase in the molecular weight of the formed supramolecular polymers in water.

The goal of this experiment is to determine and control the size, shape and stability of self-assembled discotic amphiphiles in water. For aqueous based supramolecular polymers such level of control is very difficult. We apply a strategy using both repulsive and attractive interactions. The experimental techniques applied to characterize this system are broadly applicable.

控制的大小，形状和稳定性超分子聚合物在水

For aqueous based supramolecular polymers, the simultaneous control over shape, size and stability is very difficult1. At the same time, the ability to do ...

科研

工程学

Concurrent Quantitative Conductivity and Mechanical Properties Measurements of Organic Photovoltaic Materials using AFM

Organic photovoltaic (OPV) materials are inherently inhomogeneous at the nanometer scale. Nanoscale inhomogeneity of OPV materials affects performance of photovoltaic devices. Thus, understanding of spatial variations in composition as well as electrical properties of OPV materials is of paramount importance for moving PV technology forward.1,2 In this paper, we describe a protocol for quantitative measurements of electrical and mechanical properties of OPV materials with sub-100 nm resolution. Currently, materials properties measurements performed using commercially available AFM-based techniques (PeakForce, conductive AFM) generally provide only qualitative information. The values for resistance as well as Young's modulus measured using our method on the prototypical ITO/PEDOT:PSS/P3HT:PC61BM system correspond well with literature data. The P3HT:PC61BM blend separates onto PC61BM-rich and P3HT-rich domains. Mechanical properties of PC61BM-rich and P3HT-rich domains are different, which allows for domain attribution on the surface of the film. Importantly, combining mechanical and electrical data allows for correlation of the domain structure on the surface of the film with electrical properties variation measured through the thickness of the film.

Organic photovoltaic (OPV) materials are inherently inhomogeneous at the nanometer scale. Nanoscale inhomogeneity of OPV materials affects performance of photovoltaic devices. In this paper, we describe a protocol for quantitative measurements of electrical and mechanical properties of OPV materials with sub-100 nm resolution.

并行定量的导电性和力学性能测试的有机光伏材料利用原子力显微镜

Organic photovoltaic  (OPV) materials are inherently inhomogeneous at the nanometer scale. Nanoscale  inhomogeneity of OPV materials affects performance ...

Scalable Nanohelices for Predictive Studies and Enhanced 3D Visualization

Spring-like materials are ubiquitous in nature and of interest in nanotechnology for energy harvesting, hydrogen storage, and biological sensing applications.&#160; For predictive simulations, it has become increasingly important to be able to model the structure of nanohelices accurately.&#160; To study the effect of local structure on the properties of these complex geometries one must develop realistic models.&#160; To date, software packages are rather limited in creating atomistic helical models.&#160; This work focuses on producing atomistic models of silica glass (SiO2) nanoribbons and nanosprings for molecular dynamics (MD) simulations. Using an MD model of &#8220;bulk&#8221; silica glass, two computational procedures to precisely create the shape of nanoribbons and nanosprings are presented.&#160; The first method employs the AWK programming language and open-source software to effectively carve various shapes of silica nanoribbons from the initial bulk model, using desired dimensions and parametric equations to define a helix.&#160; With this method, accurate atomistic silica nanoribbons can be generated for a range of pitch values and dimensions.&#160; The second method involves a more robust code which allows flexibility in modeling nanohelical structures.&#160; This approach utilizes a C++ code particularly written to implement pre-screening methods as well as the mathematical equations for a helix, resulting in greater precision and efficiency when creating nanospring models.&#160; Using these codes, well-defined and scalable nanoribbons and nanosprings suited for atomistic simulations can be effectively created.&#160; An added value in both open-source codes is that they can be adapted to reproduce different helical structures, independent of material.&#160; In addition, a MATLAB graphical user interface (GUI) is used to enhance learning through visualization and interaction for a general user with the atomistic helical structures.&#160; One application of these methods is the recent study of nanohelices via MD simulations for mechanical energy harvesting purposes.

Accurate modeling of nanohelical structures is important for predictive simulation studies leading to novel nanotechnology applications.&#160; Currently, software packages and codes are limited in creating atomistic helical models.&#160; We present two procedures designed to create atomistic nanohelical models for simulations, and a graphical interface to enhance research through visualization.

可扩展的Nanohelices的预测研究和增强的3D可视化

Spring-like materials are ubiquitous in nature and of interest in nanotechnology for energy harvesting, hydrogen storage, and biological sensing ...

Ultrasonic Welding of Thermoplastic Composite Coupons for Mechanical Characterization of Welded Joints through Single Lap Shear Testing

This paper presents a novel straightforward method for ultrasonic welding of thermoplastic-composite coupons in optimum processing conditions. The ultrasonic welding process described in this paper is based on three main pillars. Firstly, flat energy directors are used for preferential heat generation at the joining interface during the welding process. A flat energy director is a neat thermoplastic resin film that is placed between the parts to be joined prior to the welding process and heats up preferentially owing to its lower compressive stiffness relative to the composite substrates. Consequently, flat energy directors provide a simple solution that does not require molding of resin protrusions on the surfaces of the composite substrates, as opposed to ultrasonic welding of unreinforced plastics. Secondly, the process data provided by the ultrasonic welder is used to rapidly define the optimum welding parameters for any thermoplastic composite material combination. Thirdly, displacement control is used in the welding process to ensure consistent quality of the welded joints. According to this method, thermoplastic-composite flat coupons are individually welded in a single lap configuration. Mechanical testing of the welded coupons allows determining the apparent lap shear strength of the joints, which is one of the properties most commonly used to quantify the strength of thermoplastic composite welded joints.

A straightforward procedure for ultrasonic welding of thermoplastic composite coupons for basic mechanical testing is described. Key characteristics of this ultrasonic welding process are the use of flat energy directors for simplified process preparation and the use of process data for the fast definition of optimum processing conditions.

通过单搭接剪切试验的热塑性复合材料优惠券焊接接头的力学特性的超声波焊接

This paper presents a novel straightforward method for ultrasonic welding of thermoplastic-composite coupons in optimum processing conditions. The ...

Advanced Compositional Analysis of Nanoparticle-polymer Composites Using Direct Fluorescence Imaging

The fabrication of polymer-nanoparticle composites is extremely important in the development of many functional materials. Identifying the precise composition of these materials is essential, especially in the design of surface catalysts, where the surface concentration of the active component determines the activity of the material. Antimicrobial materials which utilize nanoparticles are a particular focus of this technology. Recently swell encapsulation has emerged as a technique for inserting antimicrobial nanoparticles into a host polymer matrix. Swell encapsulation provides the advantage of localizing the incorporation to the external surfaces of materials, which act as the active sites of these materials. However, quantification of this nanoparticle uptake is challenging. Previous studies explore the link between antimicrobial activity and surface concentration of the active component, but this is not directly visualized. Here we show a reliable method to monitor the incorporation of nanoparticles into a polymer host matrix via swell encapsulation. We show that the surface concentration of CdSe/ZnS nanoparticles can be accurately visualized through cross-sectional fluorescence imaging. Using this method, we can quantify the uptake of nanoparticles via swell encapsulation and measure the surface concentration of encapsulated particles, which is key in optimizing the activity of functional materials.

Here we present a reliable method to monitor the incorporation of nanoparticles into a polymer host matrix via swell encapsulation. We show that the surface concentration of cadmium selenide quantum dots can be accurately visualized through cross-sectional fluorescence imaging.

纳米粒子 - 聚合物复合材料使用直接荧光成像的先进成分分析

The fabrication of polymer-nanoparticle composites is extremely important in the development of many functional materials. Identifying the precise ...

Nanostructured Ag-zeolite Composites as Luminescence-based Humidity Sensors

Small silver clusters confined inside zeolite matrices have recently emerged as a novel type of highly luminescent materials. Their emission has high external quantum efficiencies (EQE) and spans the whole visible spectrum. It has been recently reported that the UV excited luminescence of partially Li-exchanged sodium Linde type A zeolites [LTA(Na)] containing luminescent silver clusters can be controlled by adjusting the water content of the zeolite. These samples showed a dynamic change in their emission color from blue to green and yellow upon an increase of the hydration level of the zeolite, showing the great potential that these materials can have as luminescence-based humidity sensors at the macro and micro scale. Here, we describe the detailed procedure to fabricate a humidity sensor prototype using silver-exchanged zeolite composites. The sensor is produced by suspending the luminescent Ag-zeolites in an aqueous solution of polyethylenimine (PEI) to subsequently deposit a film of the material onto a quartz plate. The coated plate is subjected to several hydration/dehydration cycles to show the functionality of the sensing film.

A protocol for the synthesis of moisture-responsive luminescent Ag-zeolite composites is described in this report.

纳米银沸石复合材料作为基于发光的湿度传感器

Small silver clusters confined inside zeolite matrices have recently emerged as a novel type of highly luminescent materials. Their emission has high ...

A Novel Biaxial Testing Apparatus for the Determination of Forming Limit under Hot Stamping Conditions

The hot stamping and cold die quenching process is increasingly used to form complex shaped structural components of sheet metals. Conventional experimental approaches, such as out-of-plane and in-plane tests, are not applicable to the determination of forming limits when heating and rapid cooling processes are introduced prior to forming for tests conducted under hot stamping conditions. A novel in-plane biaxial testing system was designed and used for the determination of forming limits of sheet metals at various strain paths, temperatures, and strain rates after heating and cooling processes in a resistance heating uniaxial testing machine. The core part of the biaxial testing system is a biaxial apparatus, which transfers a uniaxial force provided by the uniaxial testing machine to a biaxial force. One type of cruciform specimen was designed and verified for the formability test of aluminum alloy 6082 using the proposed biaxial testing system. The digital image correlation (DIC) system with a high-speed camera was used for taking strain measurements of a specimen during a deformation. The aim of proposing this biaxial testing system is to enable the forming limits of an alloy to be determined at various temperatures and strain rates under hot stamping conditions.

This protocol proposes a novel biaxial testing system used on a resistance heating uniaxial tensile test machine in order to determine the forming limit diagram (FLD) of sheet metals under hot stamping conditions.

一种新型双轴试验设备的成形极限的下烫印条件的决定

The hot stamping and cold die quenching process is increasingly used to form complex shaped structural components of sheet metals. Conventional ...

Subsurface Defect Localization by Structured Heating Using Laser Projected Photothermal Thermography

The presented method is used to locate subsurface defects oriented perpendicularly to the surface. To achieve this, we create destructively interfering thermal wave fields that are disturbed by the defect. This effect is measured and used to locate the defect. We form the destructively interfering wave fields by using a modified projector. The original light engine of the projector is replaced with a fiber-coupled high-power diode laser. Its beam is shaped and aligned to the projector&#39;s spatial light modulator and optimized for optimal optical throughput and homogeneous projection by first characterizing the beam profile, and, second, correcting it mechanically and numerically. A high-performance infrared (IR) camera is set up according to the tight geometrical situation (including corrections of the geometrical image distortions) and the requirement to detect weak temperature oscillations at the sample surface. Data acquisition can be performed once a synchronization between the individual thermal wave field sources, the scanning stage, and the IR camera is established by using a dedicated experimental setup which needs to be tuned to the specific material being investigated. During data post-processing, the relevant information on the presence of a defect below the surface of the sample is extracted. It is retrieved from the oscillating part of the acquired thermal radiation coming from the so-called depletion line of the sample surface. The exact location of the defect is deduced from the analysis of the spatial-temporal shape of these oscillations in a final step. The method is reference-free and very sensitive to changes within the thermal wave field. So far, the method has been tested with steel samples but is applicable to different materials as well, in particular to temperature sensitive materials.

This method aims at locating vertical subsurface defects. Here, we couple a laser with a spatial light modulator and trigger its video input to heat a sample surface deterministically with two anti-phased modulated lines while acquiring highly resolved thermal images. The defect position is retrieved from evaluating thermal wave interference minima.

使用激光投射光热法构造加热的地下缺陷定位

The presented method is used to locate subsurface defects oriented perpendicularly to the surface. To achieve this, we create destructively interfering ...

Preparation of Aligned Steel Fiber Reinforced Cementitious Composite and Its Flexural Behavior

The aim of this work is to present an approach, inspired by the way in which a compass needle maintains a consistent orientation under the action of the Earth&#39;s magnetic field, for manufacturing a cementitious composite reinforced with aligned steel fibers. Aligned steel fiber reinforced cementitious composites (ASFRC) were prepared by applying a uniform electromagnetic field to fresh mortar containing short steel fibers, whereby the short steel fibers were driven to rotate in alignment with the magnetic field. The degree of alignment of steel fibers in hardened ASFRC was assessed both by counting steel fibers in fractured cross-sections and by X-ray computed tomography analysis. The results from the two methods show that the steel fibers in ASFRC were highly aligned while the steel fibers in non-magnetically treated composites were randomly distributed. The aligned steel fibers had a much higher reinforcing efficiency, and the composites, therefore, exhibited significantly enhanced flexural strength and toughness. The ASFRC is thus superior to SFRC in that it can withstand greater tensile stress and more effectively resist cracking.

This protocol describes an approach for manufacturing aligned steel fiber reinforced cementitious composite by applying a uniform electromagnetic field. Aligned steel fiber reinforced cementitious composite exhibits superior mechanical properties to ordinary fiber reinforced concrete.

定向钢纤维增强水泥基复合材料的制备及其弯曲性能研究

The aim of this work is to present an approach, inspired by the way in which a compass needle maintains a consistent orientation under the action of the ...

Installation Method to Enhance Quality Control for Fiber Reinforced Polymer Spike Anchors

Fiber reinforced polymer (FRP) anchors are a promising way to enhance the performance of externally-bonded FRPs applied to existing structures, as they can delay or even prevent debonding failure. However, a major concern faced by designers is the premature failure of the anchors due to stress concentration. Poor installation quality and preparation of the clearance holes can result in stress concentration that provokes this premature failure. This paper deals with an installation method that aims to reduce the impact of the stress concentration and to provide a proper quality control of the preparation of the drill hole. The method involves three parts: the drilling and cleaning of the holes, the smoothing of the hole edges with a customized drill bit, and the installation of the anchor itself, including the impregnation of the anchor dowel and its insertion. Anchor fans (the free length of the spikes) are then bonded to the external FRP reinforcement. For the end anchorage, and in the case of reinforcements with multiple plies, it is recommended that the anchor fan be inserted between two plies to assist the stress-transfer mechanism. 
The proposed procedure is complemented with a design approach for spike anchors, based on an extensive database. It is proposed that the design follow a number of steps, namely: selection of the anchor diameter and subsequent tensile strength of the connector (that is to say, the anchor before fanning out the free end), evaluation of the reduction in the tensile strength due to bending, provision of enough embedment to prevent slippage failure, and consideration of the number and spacing of anchors for a given reinforcement. In this sense, it should be noted that further research is needed in order to obtain a general expression for the contribution of spike anchors to overall bond strength of FRP reinforcements.

This manuscript presents a method for controlling the quality of installation for spike anchors designed to delay delamination of externally bonded fiber reinforced polymers. The protocol includes the preparation of the drill hole and the insertion process. The most influential parameters on the efficiency of the anchors are discussed.

提高纤维增强聚合物穗锚质量控制的安装方法

Fiber reinforced polymer (FRP) anchors are a promising way to enhance the performance of externally-bonded FRPs applied to existing structures, as they ...