Name: methods for measuring the orientation and rotation rate of 3d-printed particles in turbulence
Uploaded: 2016-06-24T13:00:00.000+00:00
Duration: 12 min 34 s
Description: Watch this Scientific Journal Video about Methods for Measuring the Orientation and Rotation Rate of 3D-printed Particles in Turbulence at JoVE.com

我们感谢Susantha Wijesinghe谁设计和建造我们使用了图像压缩系统。我们承认从美国国家科学基金会资助DMR-1208990的支持。

1.粒子的制备<ol><li>使用3D计算机辅助绘图程序来创建粒子模型。导出每模型中的一个文件中，可以由所使用的三维打印机进行处理的文件格式。 <ol><li>使用CIRCLE命令绘制圆形，直径为0.3毫米。使用挤出功能，使一个气缸为3毫米的长度。 </li><li>请用一个共同的中心两个正交缸交叉;使用一个共同的中心三个相互垂直的圆柱体插孔;使一个四分与四个气缸分享在109.5°的角度彼此共同的端;使一个三元组与三个气缸在一个平面上，在120°角方向上共享公共端彼此。 </li><li>倾斜缸相（以下称为颗粒的"臂"），以彼此，使用旋转3D命令在其端部之一，以绘制整个圆的直径的线，然后输入旋转所需的角度。 </li><li>使用UNION命令乔在不同的武器组合成一个单一的防水对象。 </li><li>再次使用旋转三维倾斜该对象，以便没有手臂沿着垂直或水平轴，因为沿着这些轴线位于臂往往有缺陷，更容易折断，或变平。 </li><li>导出的每个对象的格式一个单独的文件，可以通过3D打印机使用。 </li></ol></li><li>从专业添加剂制造或可用的设备打印它们商业来源订购约10,000每种类型的粒子。颗粒应当使用能够溶解掉不同材料的载体基质聚合物挤压打印机上打印。 <ol><li>订购颗粒三周以上之前计划实验因为有太多的颗粒的排列和打印是一个缓慢的过程。确保颗粒被印上"高分辨率模式"，因为该颗粒附近有许多三维打印机的最小特征尺寸和一个有效值不会像对称和如果打印在较低的分辨率可能会断裂。 </li></ol></li></ol> 2.颗粒的制备<ol><li>制备盐溶液，其中所述颗粒是中性​​浮力，以尽量减少微粒的胳膊弯曲，而在贮存和使重力和浮力的力不必进行会计处理在分析中。 <ol><li>测试在密度左右1.20克/厘米3通过在水与氯化钙混合溶液中浸渍的颗粒平均粒子密度（ 氯化钙 ）。 <ol><li>为了确定水的密度，第一个零刻度，而空的100 mL容量瓶中是在它的上面。取该烧瓶并用水与氯化钙混合填充。放置烧瓶背面规模顶上并加入100ml除以给定质量。 注意:因为进行1毫升= 1厘米3,1微克/毫升= 1克/厘米3。 </li><li>许多不同的解决方案密度测试颗粒，范围为1.16克/厘米3至1.25克/厘米3，在大致0.01克/ cm 3的增量。在每一个密度测试多个颗粒，因为不是所有的粒子将具有相同密度:在同一个解决方案，有些人会下沉，有的会是中性浮力，有的会漂浮。 </li></ol></li><li>记录在该密度颗粒，平均而言，中性浮力几个小时之后。 注意:发现密度可以从由粒子制造商所引述的堆积密度显著不同。 </li><li>混合大约400千克的 CaCl 2到约1600升水直到溶液是在记录在2.1.1密度- 2.1.2。 </li><li>除去约1L每个颗粒类型（插口，四分体等 ），以用于粒子存储该混合溶液。持每公升在室温下的不同的容器。存储在室温下，在大的存储罐中的溶液的剩余部分。 </li></ol></li></ol> 图1. 在树脂除去的各个阶段A插口。 一个 ）的支持树脂的使颗粒到达。b）从所述其余部分。CE分离的单个块）手工。˚F完成树脂去除）的单一的多阶段的块插孔的NaOH浴缸和罗丹明-B染色后， <a href="https://www.jove.com/files/ftp_upload/53599/53599fig1large.jpg" target="_blank">请点击此处查看该图的放大版本。</a> <ol start="2"><li>手动松开其中颗粒而来轻轻破碎大块包封在载体材料（〜5毫米×320毫米，其中的一部分在图1a中示出）成小部分（约5毫米×5mm时， 图1b），然后手动按摩每个部分，直到大部分多余的树脂已脱落（ 图1C-E）。祛瘀È过量树脂以这种方式来减少所述NaOH溶液，将需要的步骤2.2.1要创建的量 - 2.2.4。 <ol><li>放置在10％的剩余树脂块通过浸于超声波浴中一小时质量氢氧化钠（NaOH）溶液。树脂是不同的材料的粒子，因此该NaOH将除去树脂不会永久影响颗粒。 小心:该溶液是腐蚀性的，将在超声波浴得到热而。 </li><li>过滤掉颗粒。 <ol><li>要过滤颗粒，使用创建一个网漏斗0.1016厘米点¯x0.13462厘米塑料孔。持用于处置该NaOH溶液的漏斗在容器和慢慢倒入通过溶液。 NaOH溶液按照环境健康和安全准则进行处理。 </li></ol></li><li>用清水冲洗颗粒轻轻地在超声波浴在新的10％的浸渍质量NaOH溶液的另一半小时前。 </l我&gt; <li>过滤掉颗粒如在2.2.2.1和2.1.4中分离出来，而他们硬化，密度相匹配的存储解决方案。小心处理，因为颗粒的NaOH溶液暂时软化他们。 注意:如果颗粒没有存储在密度匹配溶液，有些臂可以弯曲。保持它们浸渍在几个小时的密度匹配解决方案还允许在塑料一些空隙填充流体。 </li></ol></li><li>罗丹明-B染料颗粒与水混合，使它们通过一个绿色激光发射的光下发出荧光。 <ol><li>以0.5g​​ / L的浓度制备在水中的罗丹明-B染料的1升溶液（以后称为"染料"）。 注意:有毒。 </li><li>加热该染料到50和80℃之间的温度下，这取决于粒子材料。对于使用塑料难度更高的温度;使用的温度太高会导致臂弯曲。 </li><li>把〜2500粒，足以填满松散约25mL我n中的密度匹配的存储解决方案，在染料和保持所有在80℃下为两到三个小时，以使染料吸收到聚合物中。除去颗粒一旦他们都是粉红色的，像在图1F。 小心:热会暂时软化颗粒。 </li><li>过滤掉颗粒和存储在2.1.4分离指定的解决方案之前，冲洗。颗粒将失去其染料的一小部分，使得溶液的粉红色，但在水龙头下清洗有助于防止丢失染料的有害量。 注:平均颗粒密度将由于染色已经改变，因此，在2.1.1-2.1.2作为再次进行测试，以发现新的溶液密度在该颗粒是，平均来说，中性浮力。 </li></ol></li><li>根据需要更改散装氯化钙溶液（从2.1.3）密度。 2.1.4重复删除和密度相匹配的解决方案，新卷。处置前的存储解决方案的，现在将有少量罗丹明B D的你们在他们，按照环境健康和安全法规。 </li><li>重复2.3.2-2.3.4为连续集合〜2500颗粒，存储相同形状的所有的颗粒在2.4创建的相同密度匹配解决方案，从不同形状的颗粒分离。 注意:在约5重复2.3.2-2.3.4，所述若丹明B液将不再是足够高的浓度来有效染料颗粒。 </li><li>在处置2.3.1按照环境健康和安全法规建立的解决方案，然后重复2.3.1，并创建一个用于染料颗粒新的为0.5g / L的溶液。 </li><li> 2.6重复每5重复2.3.2-2.3.4。 </li></ol> 3.实验和光学装置<img alt="图2" src="/files/ftp_upload/53599/53599fig2.jpg" /> 图2.实验装置，在振荡网格，在重点中心观看体积之间的八角流四个摄像机通过绿色照明的Nd:YAG 激光器 ）显示了四个摄像头是如何排列和连接电脑侧视图。图13。b）显示激光，反光镜和镜头的配置，实现在中部量均匀的照明俯视图。 <a href="https://www.jove.com/files/ftp_upload/53599/53599fig2large.jpg" target="_blank">请点击此处查看该图的放大版本。</a> <ol><li>准备的摄像机。 <ol><li>使用相机至少有1万像素的分辨率，每秒450帧。 </li><li>安排，使得每个摄像机指向，并且集中于，观看体积的中心的摄像机。少摄像机可以使用，但是遮蔽由另一个臂的颗粒的臂的限制了取向的测量精度，并且具有更少的摄像机，使实验更容易受到这种影响。使用超过四个摄像头也同样可以提高定位measurem耳鼻喉科的精度，因为它会降低武器的机会被遮蔽的上所有摄像机，这是不确定性的一个主要来源。 </li><li>相机具有大（〜90°）的每对受该装置的约束之间角度的位置。放置相机如图2平衡实验访问和各个摄像机之间的角度的大小。通过建立观察口进入机器垂直于每个摄像机观察方向减少光学畸变。 </li><li>使用各摄像机200 mm宏镜片，以获得从半米的工作距离所需的测量体积。由所有四个摄像机观看的体积决定的检测体积，大约是3×3×3厘米3。 </li><li>校准摄像机以允许从测量的像素位置变换在三维空间坐标。 <ol><li>设置孔到f / 11和安装532纳米陷波滤波器去除激光，同时允许通过较长wavelengt^ h荧光到相机</li><li>放置一个图像校准掩模在罐中，从2.4填补与本体溶液的罐中，并照亮掩模。 </li><li>调节摄像机，这样他们各有鉴于掩模和他们都集中于掩模上的相同点。小心地将摄像机以优化检测体积的形状。 </li><li>要小心，尽量少改一下从这点向前光学装置。 </li><li>采集和处理来自每个摄像机的面膜储存图像。 </li><li>漏溶液从槽中取出并泵回它先前已存储在哪里。 </li><li>提取指定的位置，视线方向，放大，以及从校正图像中的每个摄像机的光学畸变的参数。通过识别在校准掩模的地方可见在所有四个摄像机和定义这些点之间的距离做到这一点。有了这些信息，使用标准的校准方法提取相关的PArameters。 注:基本校准方法仔介绍，1987 7在这些实验中使用的实施Oullette 等人被描述希望发展的相机校准软件3研究人员还可以考虑OpenPTV 4。 </li><li>创建使用动态校准过程的最终校准文件。后示踪粒子数据已被获取时完成。使用非线性最小二乘搜索优化相机校准参数，将获得看到的多个摄像机粒子的位置之间的最小失配。这些方法在参考文献8和9中描述。 </li></ol></li></ol></li><li>用Q开关绿色Nd:YAG激光器能50瓦的平均功率（以下称为"激光"）的，照亮在罐与大致3cm的横截面直径，其中流动是均匀的中心的圆柱体。 8 注意:激光功率是SP在5kHz的脉冲频率ecified。在这些实验中，脉冲频率为900赫兹，在输出功率为显著更低。 <ol><li>使用分束器将激光分割的光，并使用反射镜的一个光束引导到罐的，另外，垂直于第一的前部，插入罐的一侧。 </li><li>放置两个附加反射镜罐外，相反，其中光束被输入，以光反射回进入储罐和创建更均匀的照明，显着地减小阴影效应。 注意:从反向传播光束的干涉效应的长度规模太小，显著影响这些实验。 </li></ol></li></ol> 4.执行实验<ol><li>准备从每个摄像头录制视频。 <ol><li>程序中的图像压缩系统能够实时删除不需要的图像数据。10，1 3 <ol><li>如果相机ñOT有鉴于粒子，不保存图像。 </li><li>哪里有明亮像素，只保存位置和明亮的像素，而不是整个图像的亮度。 注意:由于每个粒子典型地覆盖大约5,000亮像素和有很少考虑一个以上的粒子在时间，图像压缩系统极大地减少了存储与高速摄像机许多小时来记录所需的时间。 </li></ol></li><li>准备数据采访软件。 </li></ol></li><li>准备在使用两个平行8厘米网状网格，相振荡1×1×1米3八角罐中的湍流。8 <ol><li>泵从2.4氯化钙2溶液放入真空室，并保持它在腔室中过夜以脱气溶液中，最大程度地减少空气中的气泡的实验。 </li><li>从真空室泵溶液通过0.2微米的过滤器进八角罐，在实验... ...万王之王执行湖</li></ol></li><li>运行实验。 </li><li>选择一种颗粒类型（示踪粒子，千斤顶，十字架，四分体，或三单元组），以用于在第一轮实验中，并在该装置的顶部添加这些颗粒的所有10,000个入水通过的端口。加入颗粒后关闭此端口。 <ol><li>开启激光器。 </li><li> Set摄像机和激光来响应外部触发和触发的频率设定为450赫兹的摄像机和900赫兹的激光。使用外部触发器，以确保所有的摄像机同时开始采集并在整个记录保持同步</li><li>打开激光孔。 </li><li>设置网格所选择的频率（1或3赫兹），并开始运行它。在开始数据采集之前，运行约1分钟电网，让动荡充分发展。 </li><li>为了确保文件大小的可管理，并保持在图像中可能出现的任何错误记录10 6帧从牺牲太多的数据压缩系统。 </li><li>关闭激光光圈和停止摄像触发。重置图像压缩系统和摄像机。 <ol><li>检查视频文件不通过查看每个文件的部分损坏。 </li></ol></li><li>重复4.4.1 - 4.4.6至10 7的图像被记录在为选定的粒子所选择的电网频率。 </li></ol></li><li>电网频率改为4.4.4未选择之一，重复4.4.4 - 4.4.7 </li><li>清空油箱和过滤去除水中的所有粒子。如果需要的话在存储水从2.4减颗粒。 </li><li>重复4.4 - 4.6所有粒子类型。 </li><li>所有的实验已经完成后，相机校准一次，在3.1.5-3.1.5.7。 </li></ol> 5.数据分析注意:该议定书的本节介绍用于获取粒子的取向和旋转速率的过程的概述。具体programs使用，测试图像和校准文件一起，包括作为补充本出版物，并开放给任何有兴趣的读者使用。 （参见在补充文件"MATLAB_files.zip"文件"Use_Instructions.txt"）。 <ol><li>使用相机校准参数，取得从多个摄像机颗粒图像的三维位置和方向。 <ol><li>在每一帧，发现粒子的每四个图像的中心。在这些实验中所有颗粒足够对称的该物体的中心是在图像上的明亮像素的几何中心，从任何角度看时。 </li><li>通过在所有四个摄像机3,8 stereomatching其同步2D位置找到颗粒的三维位置。 </li><li>创建可以被投影到每个摄像机的强度从该照相机图像中建模粒子的数值模型。 <ol><li>模型中的PArticle作为杆的复合物。从3.1.5.7和3.1.5.8使用相机校准参数，突出各杆的两端点到摄像机，然后光强度的分布进行建模以二维，与整个棒和费米的宽度的高斯函数根据软件协议在其整个长度-Dirac功能。 </li><li>在这样两个维度模型光照强度以减少数据分析的计算成本。荧光颗粒的全三维模型的投影可以改进这种方法，但会更密集计算。 </li><li>点击Run开始分析。 </li></ol></li><li>选择粒子取向的初始猜测。 <ol><li>如果分析第一帧，其中该颗粒是可见的，所述第一猜测可以是一组随机欧拉角。 </li><li>如果此颗粒是在至少一个先前帧，使用使用先前帧中找到的取向初始猜测。 </li></ol></li><li>最小二乘执行非线性拟合以确定粒子取向。 <ol><li>优化这三个三维位置坐标和三个欧拉角，使得所测量的强度和模型的2D投影之间的平方差，根据软件协议最小化在所有四个摄像机。 注:有定义欧拉角多约定。定义角度（φ，θ，ψ），具体如下:φ是围绕z轴的初始旋转，创造新的轴x&#39;和y&#39;; θ是一个关于x的旋转"，创造新的轴Z&#39;和y&#39;&#39;; ψ是一个关于新的z&#39;轴转动。11 </li></ol></li><li>选择，需要相对于先前帧的最小旋转的方向。对于一个插孔，欧拉角度发现给予24的对称方向之一; F或一个四分它是12对称取向之一;为一过性，它是8对称方向之一;并为黑社会它是6对称的方向之一。 注意:在5.1.6的方法，假定粒子不会旋转超过半帧之间的内角的一个以上。这种假设的理由在讨论中给出。 </li></ol></li><li>保存的位置和欧拉角为时间的函数。 </li><li>利用这些数据来提取固体旋转速度与数量。 </li></ol>

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Lett. 109 (13), 134501 (2012).</li><li>Parsa, S., Voth, G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Inertial+Range+Scaling+in+Rotations+of+Long+Rods+in+Turbulence.">Inertial Range Scaling in Rotations of Long Rods in Turbulence.</a> Phys. Rev. Lett. 112 (2), 024501 (2014).</li><li>Tsai, R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+versatile+camera+calibration+technique+for+high-accuracy+3d+machine+vision+metrology+using+off-the-shelf+tv+cameras+and+lenses.">A versatile camera calibration technique for high-accuracy 3d machine vision metrology using off-the-shelf tv cameras and lenses.</a> IEEE Journal of Robotics and Automation. 3 (4), 323-344 (1987).</li><li>Blum, D., Kunwar, S., Johnson, J., Voth, G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Effects+of+nonuniversal+large+scales+on+conditional+structure+functions+in+turbulence.">Effects of nonuniversal large scales on conditional structure functions in turbulence.</a> Phys. Fluids. 22 (1), 015107 (2010).</li><li>Mann, J., Ott, S., Andersen, J. S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Experimental+study+of+relative,+turbulent+diffusion.">Experimental study of relative, turbulent diffusion.</a> RISO Internal Report. , (1999).</li><li>Chan, K., Stich, D., Voth, G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Real-time+image+compression+for+high-speed+particle+tracking.">Real-time image compression for high-speed particle tracking.</a> Rev. Sci. Instrum. 78 (2), 023704 (2007).</li><li>Goldstein, H., Poole, C., Safko, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> Classical Mechanics, 3rd Edition. , 134-180 (2002).</li><li>Parsa, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> Rotational dynamics of rod particles in fluid flows. , (2013).</li><li>Wijesinghe, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> Measurement of the effects of large scale anisotropy on the small scales of turbulence. , (2012).</li><li>Wallace, J., Foss, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+Measurement+of+Vorticity+in+Turbulent+Flows.">The Measurement of Vorticity in Turbulent Flows.</a> Annu. Rev. Fluid Mech. 27, 469-514 (1995).</li><li>Su, L., Dahm, W. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Scalar+imaging+velocimetry+measurements+of+the+velocity+gradient+tensor+field+in+turbulent+flows.+I.+Assessment+of+errors.">Scalar imaging velocimetry measurements of the velocity gradient tensor field in turbulent flows. I. Assessment of errors.</a> Phys. Fluids. 8, 1869-1882 (1996).</li><li>L&#252;thi, B., Tsinober, A., Kinzelbach, W. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Lagrangian+measurement+of+vorticity+dynamics+in+turbulent+flow.">Lagrangian measurement of vorticity dynamics in turbulent flow.</a> J. Fluid Mech. 528, 87-118 (2005).</li><li>Frish, M., Webb, W. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Direct+measurement+of+vorticity+by+optical+probe.">Direct measurement of vorticity by optical probe.</a> J. Fluid Mech. 107, 173-200 (1981).</li><li>Zimmerman, R., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Tracking+the+dynamics+of+translation+and+absolute+orientation+of+a+sphere+in+a+turbulent+flow.">Tracking the dynamics of translation and absolute orientation of a sphere in a turbulent flow.</a> Rev. Sci. Instrum. 82 (3), 033906 (2011).</li><li>Zimmerman, R., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Rotational+Intermittency+and+Turbulence+Induced+Lift+Experienced+by+Large+Particles+in+a+Turbulent+Flow.">Rotational Intermittency and Turbulence Induced Lift Experienced by Large Particles in a Turbulent Flow.</a> Phys. Rev. Lett. 106 (15), 154501 (2011).</li><li>Klein, S., Gibert, M. a. t. h. i. e. u., B&#233;rut, A., Bodenschatz, E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Simultaneous+3D+measurement+of+the+translation+and+rotation+of+finite-size+particles+and+the+flow+field+in+a+fully+developed+turbulent+water+flow.">Simultaneous 3D measurement of the translation and rotation of finite-size particles and the flow field in a fully developed turbulent water flow.</a> Meas. Sci. Technol. 24 (2), 1-10 (2013).</li><li>Bellani, G., Byron, M., Collignon, A., Meyer, C., Variano, E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Shape+effects+on+turbulent+modulation+by+large+nearly+neutrally+buoyant+particles.">Shape effects on turbulent modulation by large nearly neutrally buoyant particles.</a> J. Fluid Mech. 712, 41-60 (2012).</li></ol>

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涡度和湍流流体流动粒子的旋转测量已长期被认为是在实验流体力学的重要目标。小球在湍流的固体旋转等于一半的流体涡，但球的旋转对称性还使他们的固体旋转困难的直接测量。传统上，流体涡已经使用复杂的多传感器测量，热丝探头14。但是这些传感器只获得在具有大的平均流速的气流单点涡测量。其他涡测量方法已经开发了。例如，苏和达姆采用基于标图像15LÜTHI，Tsinober...

在最近发布，我们推出了使用多个修长的手臂，用于测量动荡1粒子的旋转运动由粒子组成的。这些颗粒可以利用三维打印机使用多个摄像机的旋转速度来制造，并且可以精确地测量他们的位置，方向，和。使用工具从细长体理论，可以证明，这些粒子有对应的有效椭球2，并且这些粒子的旋转运动是相同的各自的有效的椭球。与相同长度的对称武器的粒子旋转球一样。一个这样的颗粒是插口，其具有附接在其中心三个相互垂直的臂。调整千斤顶的臂的相对长度可形成粒子等同于任何三轴椭球。如果一个臂的长度被设定等于零，这创建了一个交叉，其等效椭圆体是一个磁盘。修长制成颗粒武器背起他们的固体椭同行的固体体积的一小部分。其结果是，他们滓更慢，这使得它们更容易密度匹配。这允许更大的颗粒的研究比是方便与固体椭圆颗粒。此外，成像可以在高得多的粒子浓度，因为颗粒阻挡来自其它颗粒的光的较小部分进行。 在本文中，对于制造和3D印刷颗粒的跟踪方法被记录。用于跟踪由多个相机所看到从粒子位置球形颗粒的平移运动的工具已被几个小组3,4-开发的。伯尔萨等 5扩展这种方法来跟踪使用由多个摄像机看到的杆的位置和方向的棒。这里，我们提出的用于制造的各种各样的形状的颗粒和重建他们的3D取向的方法。这提供日Ë可能性具有复杂形状的颗粒3D追踪扩展到范围广泛的新应用。 该技术有进一步的发展，因为宽范围的粒子的形状可设计的巨大潜力。许多这些形状在环境流量，其中浮游生物，种子和冰晶进来形状繁多直接应用。粒子的旋转和湍流6基本小型性质之间的联系表明，这些粒子的旋转研究提供了新的方式来看待汹涌的级联过程。

<table><tbody><tr><td>Condor Nd:YAG 50 W laser</td><td>Quantronics</td><td>532-30-M</td><td></td></tr><tr><td>High speed camera</td><td>Basler</td><td>A504k</td><td></td></tr><tr><td>High speed camera</td><td>Mikrotron</td><td>EoSens Mc1362</td><td></td></tr><tr><td>Rhodamine-B</td><td>ScienceLab.com</td><td>SLR1465</td><td></td></tr><tr><td>Sodium Hydroxide</td><td>Macron</td><td>7708</td><td>Pellets.</td></tr><tr><td>500 Connex 3D printer</td><td>Objet</td><td></td><td>Used to make smaller particles. Particles ordered from RP+M (rapid prototyping plus manufacturing).</td></tr><tr><td>VeroClear</td><td>Stratasys</td><td>RGD810</td><td>Objet build material.</td></tr><tr><td>Clear Form 1 Photopolymer Resin</td><td>Formlabs</td><td></td><td></td></tr><tr><td>Cylindrical and spherical lenses</td><td></td><td></td><td></td></tr><tr><td>200 mm macro camera lenses</td><td></td><td></td><td>F-mount.</td></tr><tr><td>Ultrasonic bath</td><td>Sonicator</td><td></td><td></td></tr><tr><td>Calcium Chloride</td><td>Spectrum Chemical Mfg. Corp.</td><td>CAS 10043-52-2</td><td>Pellets.</td></tr><tr><td>LabVIEW System Design Software</td><td>National Instruments</td><td></td><td>Used to trigger cameras, control grid, and trigger laser.</td></tr><tr><td>XCAP Software</td><td>EPIX</td><td></td><td>Used with LabVIEW to trigger cameras.</td></tr><tr><td>MATLAB</td><td>Mathworks</td><td></td><td>Used for all image and data analysis. Programs for extracting 3D orientations from multiple images are included with this publication.</td></tr><tr><td>OpenPTV: Open Source Particle Tracking Velocimetry</td><td>OpenPTV Consortium</td><td></td><td></td></tr><tr><td>ParaView</td><td>Kitware</td><td></td><td></td></tr><tr><td>AutoCAD</td><td>AutoDesk</td><td></td><td>Used to design all particles. Screenshots of particle designs are all of AutoCAD.</td></tr><tr><td>Mesh with 0.040 x 0.053 inch holes</td><td>Industrial Netting</td><td>XN5170&amp;ndash;43.5</td><td></td></tr><tr><td>Camera filters</td><td>Schneider Optics</td><td>B+W 040M</td><td></td></tr></tbody></table>

methods for measuring the orientation and rotation rate of 3d-printed particles in turbulence

实验方法都用于测量在湍流流体流动各向异性颗粒的旋转和平移运动。三维印刷技术用于制造具有在一个共同的中心连接的细长臂的颗粒。探索形状杂交（两个垂直杆），插孔（三个垂直杆），黑社会（三个杆三角平面对称），和四分体（四臂在四面体对称）。为年产10000荧光染色的颗粒的顺序上的方法进行说明。它们的取向和固体旋转速度的时间分辨测量从他们的运动四个同步视频中的紊流被Rλ= 91振荡网格在这种相对低雷诺数流之间得到的平流输送颗粒是足够小它们近似椭圆示踪粒子。我们提出的作为粒子的位置和方向时间分辨三维轨迹的结果以及它们的旋转速度的测量。

图3a示出一个四分体从我们的相机欧拉的曲线上方一项所述的图像的角度从它的轨迹（ 图3c）的部分获得。在图3b中，取向寻找算法，在协议5中描述的结果- 5.3，叠加四分体图像上。 图3a四分体的武器不遵守，用于创建模型的简单的强度分布（协议5.1.3.1）。这是对于所有的颗粒也是如此。所观察到的强度还具有一个非平?...

Watch this Scientific Journal Video about Methods for Measuring the Orientation and Rotation Rate of 3D-printed Particles in Turbulence at JoVE.com

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

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 ...

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3-Dimensional Kinetics of a Rigid Body

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Dynamics of Rotational Motions

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10.0K 次观看.  Wesleyan University. 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.

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

Encapsulation and Permeability Characteristics of Plasma Polymerized Hollow Particles

In this protocol, core-shell nanostructures are synthesized by plasma enhanced chemical vapor deposition. We produce an amorphous barrier by plasma polymerization of isopropanol on various solid substrates, including silica and potassium chloride. This versatile technique is used to treat nanoparticles and nanopowders with sizes ranging from 37 nm to 1 micron, by depositing films whose thickness can be anywhere from 1 nm to upwards of 100 nm. Dissolution of the core allows us to study the rate of permeation through the film. In these experiments, we determine the diffusion coefficient of KCl through the barrier film by coating KCL nanocrystals and subsequently monitoring the ionic conductivity of the coated particles suspended in water. The primary interest in this process is the encapsulation and delayed release of solutes. The thickness of the shell is one of the independent variables by which we control the rate of release. It has a strong effect on the rate of release, which increases from a six-hour release (shell thickness is 20 nm) to a long-term release over 30 days (shell thickness is 95 nm). The release profile shows a characteristic behavior: a fast release (35% of the final materials) during the first five minutes after the beginning of the dissolution, and a slower release till all of the core materials come out.

We have used plasma enhanced chemical vapor deposition to deposit thin films ranging from a few nm to several 100 nm on nano-sized particles of various materials. We subsequently etch the core material to produce hollow nanoshells whose permeability is controlled by the thickness of the shell. We characterize the permeability of these coatings to small solutes and demonstrate that these barriers can provide sustained release of the core material over several days.

等离子体聚合空心颗粒的封装和渗透特征

In this protocol, core-shell nanostructures are synthesized by plasma enhanced chemical vapor deposition. We produce an amorphous barrier by plasma ...

科研

工程学

Experimental Measurement of Settling Velocity of Spherical Particles in Unconfined and Confined Surfactant-based Shear Thinning Viscoelastic Fluids

An experimental study is performed to measure the terminal settling velocities of spherical particles in surfactant based shear thinning viscoelastic (VES) fluids. The measurements are made for particles settling in unbounded fluids&#160;and fluids between parallel walls. VES fluids over a wide range of rheological properties are prepared and rheologically characterized. The rheological characterization involves steady shear-viscosity and dynamic oscillatory-shear measurements to quantify the viscous and elastic properties respectively. The settling velocities under unbounded conditions are measured in beakers having diameters at least 25x the diameter of particles. For measuring settling velocities between parallel walls, two experimental cells with different wall spacing are constructed. Spherical particles of varying sizes are gently dropped in the fluids and allowed to settle. The process is recorded with a high resolution video camera and the trajectory of the particle is recorded using image analysis software. Terminal settling velocities are calculated from the data.
The impact of elasticity on settling velocity in unbounded fluids is quantified by comparing the experimental settling velocity to the settling velocity calculated by the inelastic drag predictions of Renaud et al.1&#160;Results show that elasticity of fluids can increase or decrease the settling velocity. The magnitude of reduction/increase is a function of the rheological properties of the fluids and properties of particles. Confining walls are observed to cause a retardation effect on settling and the retardation is measured in terms of wall factors.

This paper demonstrates the experimental procedure to measure terminal settling velocities of spherical particles in surfactant-based shear thinning viscoelastic fluids. Fluids over a wide range of rheological properties are prepared and settling velocities are measured for a range of particle sizes in unbounded fluids and fluids between parallel walls.

无约束和封闭表面活性剂中球形粒子沉降速度的实验测量 剪切变薄粘性流体

An experimental study is performed to measure the terminal settling velocities of spherical particles in surfactant based shear thinning viscoelastic ...

Automation of Mode Locking in a Nonlinear Polarization Rotation Fiber Laser through Output Polarization Measurements

When a laser is mode-locked, it emits a train of ultra-short pulses at a repetition rate determined by the laser cavity length. This article outlines a new and inexpensive procedure to force mode locking in a pre-adjusted nonlinear polarization rotation fiber laser. This procedure is based on the detection of a sudden change in the output polarization state when mode locking occurs. This change is used to command the alignment of the intra-cavity polarization controller in order to find mode-locking conditions. More specifically, the value of the first Stokes parameter varies when the angle of the polarization controller is swept and, moreover, it undergoes an abrupt variation when the laser enters the mode-locked state. Monitoring this abrupt variation provides a practical easy-to-detect signal that can be used to command the alignment of the polarization controller and drive the laser towards mode locking. This monitoring is achieved by feeding a small portion of the signal to a polarization analyzer measuring the first Stokes parameter. A sudden change in the read out of this parameter from the analyzer will occur when the laser enters the mode-locked state. At this moment, the required angle of the polarization controller is kept fixed. The alignment is completed. This procedure provides an alternate way to existing automating procedures that use equipment such as an optical spectrum analyzer, an RF spectrum analyzer, a photodiode connected to an electronic pulse-counter or a nonlinear detecting scheme based on two-photon absorption or second harmonic generation. It is suitable for lasers mode locked by nonlinear polarization rotation. It is relatively easy to implement, it requires inexpensive means, especially at a wavelength of 1550 nm, and it lowers the production and operation costs incurred in comparison to the above-mentioned techniques.

A protocol to detect and automate mode locking in a pre-adjusted nonlinear polarization rotation fiber laser is presented. The detection of a sudden change in the output polarization state when mode locking occurs is used to command the alignment of an intra-cavity polarization controller in order to find mode-locking conditions.

锁模自动化的非线性偏振旋转光纤激光器通过输出偏振测量

When a laser is mode-locked, it emits a train of ultra-short pulses at a repetition rate determined by the laser cavity length. This article outlines a ...

Three-dimensional Particle Tracking Velocimetry for Turbulence Applications: Case of a Jet Flow

3D-PTV is a quantitative flow measurement technique that aims to track the Lagrangian paths of a set of particles in three dimensions using stereoscopic recording of image sequences. The basic components, features, constraints and optimization tips of a 3D-PTV topology consisting of a high-speed camera with a four-view splitter are described and discussed in this article. The technique is applied to the intermediate flow field (5 &#60;x/d &#60;25) of a circular jet at Re &#8776; 7,000. Lagrangian flow features and turbulence quantities in an Eulerian frame are estimated around ten diameters downstream of the jet origin and at various radial distances from the jet core. Lagrangian properties include trajectory, velocity and acceleration of selected particles as well as curvature of the flow path, which are obtained from the Frenet-Serret equation. Estimation of the 3D velocity and turbulence fields around the jet core axis at a cross-plane located at ten diameters downstream of the jet is compared with literature, and the power spectrum of the large-scale streamwise velocity motions is obtained at various radial distances from the jet core.

A three-dimensional particle tracking velocimetry (3D-PTV) system based on a high-speed camera with a four-view splitter is described here. The technique is applied to a jet flow from a circular pipe in the vicinity of ten diameters downstream at Reynolds number Re &#8776; 7,000.

湍流应用三维粒子跟踪测速:一喷流病例

3D-PTV is a quantitative flow measurement technique that aims to track the Lagrangian paths of a set of particles in three dimensions using stereoscopic ...

Visually Based Characterization of the Incipient Particle Motion in Regular Substrates: From Laminar to Turbulent Conditions

Two different experimental methods for determining the threshold of particle motion as a function of geometrical properties of the bed from laminar to turbulent flow conditions are presented. For that purpose, the incipient motion of a single bead is studied on regular substrates that consist of a monolayer of fixed spheres of uniform size that are regularly arranged in triangular and quadratic symmetries. The threshold is characterized by the critical Shields number. The criterion for the onset of motion is defined as the displacement from the original equilibrium position to the neighboring one. The displacement and the mode of motion are identified with an imaging system. The laminar flow is induced using a rotational rheometer with a parallel disk configuration. The shear Reynolds number remains below 1. The turbulent flow is induced in a low-speed wind tunnel with open jet test section. The air velocity is regulated with a frequency converter on the blower fan. The velocity profile is measured with a hot wire probe connected to a hot film anemometer. The shear Reynolds number ranges between 40 and 150. The logarithmic velocity law and the modified wall law presented by Rotta are used to infer the shear velocity from the experimental data. The latter is of special interest when the mobile bead is partially exposed to the turbulent flow in the so-called hydraulically transitional flow regime. The shear stress is estimated at onset of motion. Some illustrative results showing the strong impact of the angle of repose, and the exposure of the bead to shear flow are represented in both regimes.

Two different methods for characterizing the incipient particle motion of a single bead as a function of the sediment bed geometry from laminar to turbulent flow are presented.

从层流到湍流条件下的规则基底表面初始粒子运动的可视化表征

Two different experimental methods for determining the threshold of particle motion as a function of geometrical properties of the bed from laminar to ...

Simultaneous Measurement of Turbulence and Particle Kinematics Using Flow Imaging Techniques

Numerous problems in scientific and engineering fields involve understanding the kinematics of particles in turbulent flows, such as contaminants, marine micro-organisms, and/or sediments in the ocean, or fluidized bed reactors and combustion processes in engineered systems. In order to study the effect of turbulence on the kinematics of particles in such flows, simultaneous measurements of both the flow and particle kinematics are required. Non-intrusive, optical flow measurement techniques for measuring turbulence, or for tracking particles, exist but measuring both simultaneously can be challenging due to interference between the techniques. The method presented herein provides a low cost and relatively simple method to make simultaneous measurements of the flow and particle kinematics. A cross section of the flow is measured using a particle image velocimetry (PIV) technique, which provides two components of velocity in the measurement plane. This technique utilizes a pulsed-laser for illumination of the seeded flow field that is imaged by a digital camera. The particle kinematics are simultaneously imaged using a light emitting diode (LED) line light that illuminates a planar cross section of the flow that overlaps with the PIV field-of-view (FOV). The line light is of low enough power that it does not affect the PIV measurements, but powerful enough to illuminate the larger particles of interest imaged using the high-speed camera. High-speed images that contain the laser pulses from the PIV technique are easily filtered by examining the summed intensity level of each high-speed image. By making the frame rate of the high-speed camera incommensurate with that of the PIV camera frame rate, the number of contaminated frames in the high-speed time series can be minimized. The technique is suitable for mean flows that are predominantly two-dimensional, contain particles that are at least 5 times the mean diameter of the PIV seeding tracers, and are low in concentration.

The technique described herein offers a low cost and relatively simple method to simultaneously measure particle kinematics and turbulence in flows with low particle concentrations. The turbulence is measured using particle image velocimetry (PIV), and particle kinematics are calculated from images obtained with a high-speed camera in an overlapping field-of-view.

流成像技术同时测量湍流和粒子运动学

Numerous problems in scientific and engineering fields involve understanding the kinematics of particles in turbulent flows, such as contaminants, marine ...

3D Printing - Evaluating Particle Emissions of a 3D Printing Pen

Three-dimensional (3D) printing as a type of additive manufacturing shows continuing increase in application and consumer popularity. The fused filament fabrication (FFF) is an inexpensive method used most frequently by consumers. Studies with 3D printers have shown that during the printing process particulate and volatile substances are released. Handheld 3D printing pens also use the FFF method but the consumer&#8217;s proximity to the 3D pens gives reason to higher exposure compared to a 3D printer. At the same time, 3D printing pens are often marketed for children who could be more sensitive to the printing emission. The aim of this study was to implement a low cost method to analyze the emissions of 3D printing pens. Polylactide (PLA) and acrylonitrile butadiene styrene (ABS) filaments of different colors were tested. In addition, filaments containing metal and carbon nanotubes (CNTs) were analyzed. An 18.5 L chamber and sampling close to the emission source was used to characterize emissions and concentrations near the breathing zone of the user.
Particle emissions and particle size distributions were measured and the potential release of metal particles and CNTs investigated. Particle number concentrations were found in a range of 105 - 106 particles/cm3, which is comparable to previous reports from 3D printers. Transmission electron microscopy (TEM) analysis showed nanoparticles of the different thermoplastic materials as well as of metal particles and CNTs. High contents of metal were observed by inductively coupled plasma mass spectrometry (ICP-MS).
These results call for a cautious use of 3D pens due to potential risk to the consumers.

This protocol presents a method to analyze the emission of 3D printing pens. Particle concentration and particle size distribution of the released particle is measured. Released particles are further analyzed with transmission electron microscopy (TEM). Metal content in filaments is quantified by inductively coupled plasma mass spectrometry (ICP-MS).

3D 打印 - 评估 3D 打印笔的粒子排放

Three-dimensional (3D) printing as a type of additive manufacturing shows continuing increase in application and consumer popularity. The fused filament ...

Frugal Imaging Technique of Capillary Flow Through Three-Dimensional Polymeric Printing Powders

The development of novel imaging techniques of molecular and colloidal transport, including nanoparticles, is an area of active investigation in microfluidic and millifluidic studies. With the advent of three-dimensional (3D) printing, a new domain of materials has emerged, thereby increasing the demand for novel polymers. Specifically, polymeric powders, with average particle sizes on the order of a micron, are experiencing a growing interest from academic and industrial communities. Controlling material tunability at the mesoscopic to microscopic length scales creates opportunities to develop innovative materials, such as gradient materials. Recently, a need for micron-sized polymeric powders has been growing, as clear applications for the material are developing. Three-dimensional printing provides a high-throughput process with a direct link to new applications, driving investigations into the physio-chemical and transport interactions on a mesoscale. The protocol that is discussed in this article provides a non-invasive technique to image fluid flow in packed powder beds, providing high temporal and spatial resolution while leveraging mobile technology that is readily available from mobile devices, such as smartphones. By utilizing a common mobile device, the imaging costs that would normally be associated with an optical microscope are eliminated, resulting in a frugal-science approach. The proposed protocol has successfully characterized a variety of combinations of fluids and powders, creating a diagnostic platform for quickly imaging and identifying an optimal combination of fluid and powder.

The proposed technique will provide a novel, efficient, frugal, and non-invasive approach for imaging fluidic flow through a packed powder bed, yielding high spatial and temporal resolution.

毛细管流通过三维聚合物印刷粉末的节俭成像技术

The development of novel imaging techniques of molecular and colloidal transport, including nanoparticles, is an area of active investigation in ...

可视化聚合物动力学以优化 3D 打印质量

Real-Time Imaging of Bonding in 3D-Printed Layers

In recent times, 3D printing technology has revolutionized our ability to design and produce products, but optimizing the print quality can be challenging. The process of extrusion 3D printing involves pressuring molten material through a thin nozzle and depositing it onto previously extruded material. This method relies on bonding between the consecutive layers to create a strong and visually appealing final product. This is no easy task, as many parameters, such as the nozzle temperature, layer thickness, and printing speed, must be fine-tuned to achieve optimal results. In this study, a method for visualizing the polymer dynamics during extrusion is presented, giving insight into the layer bonding process. Using laser speckle imaging, the plastic flow and fusion can be resolved non-invasively, internally, and with high spatiotemporal resolution. This measurement, which is easy to perform, provides an in-depth understanding of the underlying mechanics influencing the final print quality. This methodology was tested with a range of cooling fan speeds, and the results showed increased polymer motion with lower fan speeds and, thus, explained the poor printing quality when the cooling fan was turned off. These findings show that this methodology allows for optimizing the printing settings and understanding the material behavior. This information can be used for the development and testing of novel printing materials or advanced slicing procedures. With this approach, a deeper understanding of extrusion can be built to take 3D printing to the next level.

作者聚焦:3D 打印层中粘合的实时成像  

With a non-invasive and real-time technique, nanoscopic polymer motion inside a polymer filament is imaged during 3D printing. Fine-tuning this motion is crucial for producing constructs with optimal performance and appearance. This method reaches the core of plastic layer fusion, thus offering insights into optimal printing conditions and material design criteria.

测量的方向和旋转速率方法3D打印在湍流颗粒

摘要

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等离子体聚合空心颗粒的封装和渗透特征

无约束和封闭表面活性剂中球形粒子沉降速度的实验测量剪切变薄粘性流体

锁模自动化的非线性偏振旋转光纤激光器通过输出偏振测量

湍流应用三维粒子跟踪测速:一喷流病例

从层流到湍流条件下的规则基底表面初始粒子运动的可视化表征

流成像技术同时测量湍流和粒子运动学

3D 打印 - 评估 3D 打印笔的粒子排放

毛细管流通过三维聚合物印刷粉末的节俭成像技术

3D 打印层中粘合的实时成像

3D 打印层中粘合的实时成像

测量的方向和旋转速率方法3D打印在湍流颗粒

摘要

探索更多视频

此视频中的章节

等离子体聚合空心颗粒的封装和渗透特征

无约束和封闭表面活性剂中球形粒子沉降速度的实验测量 剪切变薄粘性流体

锁模自动化的非线性偏振旋转光纤激光器通过输出偏振测量

湍流应用三维粒子跟踪测速:一喷流病例

从层流到湍流条件下的规则基底表面初始粒子运动的可视化表征

流成像技术同时测量湍流和粒子运动学

3D 打印 - 评估 3D 打印笔的粒子排放

毛细管流通过三维聚合物印刷粉末的节俭成像技术

3D 打印层中粘合的实时成像

3D 打印层中粘合的实时成像

无约束和封闭表面活性剂中球形粒子沉降速度的实验测量剪切变薄粘性流体