作者感谢美国能源部和RPSEA的财政支持，以及赞助德克萨斯大学奥斯汀分校水力压裂和防沙的JIP的公司（液体空气、空气产品、阿纳达科、阿帕奇、贝克休斯、必和必拓、英国石油公司美国公司、雪佛龙公司、康菲石油公司、埃克森美孚公司、费鲁斯公司、哈里伯顿公司、赫斯公司、林德集团公司、佩梅克斯公司、先锋自然资源公司），普拉克斯尔，沙特阿美，斯伦贝谢，壳牌，西南能源，挪威国家石油公司，韦瑟福德和YPF）。

1. 液体的准备
本实验研究采用无聚合物、粘胶、双成分、表面活性剂为基础的流体系统。这种流体系统已用于许多生产领域的油气井，用于水力压裂处理44，45。此流体系统用于此研究，因为它具有光学透明度，流变学可以通过系统地改变两个组件的浓度和比例来控制。流体系统由一种离子表面活性剂（如硫化钠）作为组件A和一种离子表面活性剂（如N、N、N-三甲基-1-氯化钙）作为组件B。
<ol><li>在蒸馏水中加入A组件的给定浓度，然后使用架空搅拌机在高转速下混合，以确保正确混合。允许它混合2-3分钟。</li>
	<li>在此混合物中加入给定浓度的组件 B，并允许其混合 2-3 分钟。</li>
	<li>将混合物休息2-6小时，以排出气泡。注意:最终的液体混合物是光学透明的。在这项研究中，使用了七种不同浓度的液体混合物。选择浓度是为了获得各种粘度的液体混合物。</li>
</ol>2. 测量未绑定流体中的沉降速度
使用直径为 1-5 毫米的玻璃球体。
<ol><li>使用高分辨率显微镜测量玻璃球体的直径。确保球体表面光滑，球体近乎完美。</li>
	<li>将液体存放在直径至少是颗粒直径 25 倍的玻璃容器中，以确保密闭壁不会对颗粒的沉降速度产生影响。</li>
	<li>使用实验室温度计记录室温和流体温度。温度测量很重要，因为流体的风湿测量应在进行沉降实验的温度下进行。</li>
	<li>将一根米棒放在容器旁边。</li>
	<li>轻轻地将玻璃颗粒浸入液体中，使其沉淀。用高分辨率摄像机记录沉降过程。</li>
	<li>使用图像分析应用程序从录制的视频中跟踪粒子在不同时间步骤的位置。注意:在这项工作中，使用了名为"跟踪器"的软件应用程序<a href="http://www.cabrillo.edu/~dbrown/tracker/" target="_blank">（http://www.cabrillo.edu/~dbrown/tracker/）。</a></li>
	<li>绘制粒子与时间的垂直位置，并计算从线的斜坡的终端沉降速度。</li>
	<li>在特殊条件下重复实验至少 3 倍，以确保可重复性。执行不同测量的图像分析，并使用错误条报告特定流体中给定粒子直径的沉降速度。</li>
	<li>重复上述步骤以处理不同直径的颗粒，并记录沉降速度。绘制沉降速度与粒子直径。注: 图1 显示一个流体中五个不同大小粒子的沉降速度。
</li>
</ol>3. 平行墙体间流体沉降速度测量
为了测量平行墙面下的沉降速度，使用了两个由Plexiglas制成的实验细胞。
<ol><li>在设计和建造单元时，确保墙壁平滑且完全平行。保持低细胞的纵横比，以确保墙壁正交对平行壁没有影响。注意:本研究中两个细胞的壁间隙分别为3.6毫米和8毫米。 图2 显示了一个实验单元的示意图。</li>
	<li>将细胞填充液体，并通过入口/出口端口轻轻释放细胞中的颗粒。用橡胶塞密封入口/出口端口，让颗粒沉淀，直到到达细胞中间。</li>
	<li>此时，小心地垂直定位细胞，让粒子沉淀。</li>
	<li>将一米棒放在细胞旁边，然后使用高分辨率摄像机记录沉降。</li>
	<li>使用实验室温度计记录室温和流体温度。这一点很重要，因为流体的风湿测量应在此温度下进行。</li>
	<li>与无限制的沉降速度测量一样，测量软件应用程序"跟踪器"中的沉降速度。重复测量至少三次，以确保可重复性，并获取每个测量的误差条。</li>
</ol>4. 流体的流体特征
<ol><li>执行稳定的剪切粘度测量，以测量流体的粘度作为剪切率的函数。注意: 在本作品中，由TA仪器采用的 ARES 流湿计采用双壁同心圆柱夹具（内杯直径:27.95 毫米，内鲍勃直径:29.50 毫米，外鲍勃直径:32.00 毫米，外侧杯径:34.00 毫米，鲍勃长度:32.00 毫米）。
</li>
	<li>将剪切速率从 0.1-800 秒 -1 变为10 点/十点测量。确保杯子的温度与在同一液体中进行沉降实验的温度相同。 图 3 显示日志绘图上一个流体样本的粘度与剪切率。</li>
	<li>对于同一流体，计算沉降实验中粒子遇到的剪切速率范围。使用表面平均粒子剪切速率定义为2V/dp 20，23，其中V是粒子的沉降速度，dp是粒子直径。</li>
	<li>在粘度与剪切率图的这一系列剪切率中 ，μ=Kγn-1适合功率定律曲线。在日志日志绘图上，此拟合将是一条直线。确定参数 K（ 流一致性索引）和 n（ 流行为索引）。 K 和 n 量化流体的粘度。 图3 显示了权力法适合同一情节。</li>
	<li>在 0.1-100 rad/秒的频率范围内执行动态振荡剪切测量，并测量弹性模数 、G'和粘性模组 、G'。以 10 点/十点进行测量。 图4显示了流体样本的G'和G'。</li>
	<li>从此数据中计算两个模组（G'/G）的比例。使用回归分析将莫杜利与麦克斯韦模型的比例调整，并计算流体的放松时间（λ）。麦克斯韦模型的两个模组比率等式为46，47:</li>
</ol><img alt="Equation 12" fo:src="/files/ftp_upload/50749/50749eq12highres.jpg" src="/files/ftp_upload/50749/50749eq12.jpg"> 液体的放松时间量化了液体的弹性。放松时间越大，液体的弹性就越大。图5显示了流体样本的G'/G'以及麦克斯韦适合。 安装通过最大限度地减少频率范围内方差测量的总和来执行。 <img alt="Equation 13" fo:src="/files/ftp_upload/50749/50749eq13highres.jpg" src="/files/ftp_upload/50749/50749eq13.jpg">
5. 确定弹性对无限沉降速度的影响
<ol><li>表示V∞VE）无界流体中粒子的实验沉降速度，其中'∞VE'是指未受约束的粘性流体。将此实验沉降速度与基于功率定律参数的明显粘度数据计算的沉降速度（V∞INEL）进行比较。使用雷纳德等人开发的表达式。1计算V∞伊内尔。导言部分提到了这些表达式。"∞INEL"是指未受约束的无弹性液体。</li>
	<li>计算V∞EL/V∞INEL的比例，并将该比率称为速度比。 速度比的价值说明了弹性对沉降速度的影响。速度比大于 1 表示由于流体弹性，速度增加/阻力减少。速度比小于 1 表示由于流体弹性，速度降低/拖动增强。</li>
	<li>绘制速度比作为不同流体粒子直径的函数，以观察弹性对不同流变流体中不同直径粒子沉降速度的影响。 图6 显示速度比作为其中一个流体中粒子直径的函数。</li>
</ol>6. 量化平行墙对沉降速度的延迟效应
<ol><li>计算壁系数，Fw为给定直径粒子，通过在平行墙体存在的情况下划分沉降速度，V∞VE到无边界流体中的沉降速度，V∞VE。</li>
	<li>对于给定的流体，将墙体因子绘制为粒子直径与墙体间距比 的函数， r . 图7 显示了在其中一个流体中沉降粒子的壁因子。该图有助于量化密闭墙对沉降速度的阻滞效应。降低墙体因子，提高墙体阻滞效果。</li>
</ol>

<ol>
	<li>Renaud, M., Mauret, E., Chhabra, R. P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Power-law+fluid+flow+over+a+sphere:+average+shear+rate+and+drag.">Power-law fluid flow over a sphere: average shear rate and drag.</a> 82, 1066-1070 (2004).</li><li>Clift, R., Grace, J. R., Weber, M. E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> Bubbles, Drops and Particles. , (1978).</li><li>Khan, A. R., Richardson, J. F. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+resistance+to+motion+of+a+solid+sphere+in+a+fluid.">The resistance to motion of a solid sphere in a fluid.</a> Chem. Eng. Sci. 62, 135-150 (1987).</li><li>Zapryanov, Z., Tabakova, 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> Dynamics of Bubbles, Drops and Rigid Particles. , (1999).</li><li>Michaelides, E. E., DeKee, D., Chhabra, R. P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Chapter+2.+Analytical+expressions+for+the+motion+of+particles.">Chapter 2. Analytical expressions for the motion of particles.</a> Transport Processes in Bubbles Drops and Particles. , (2002).</li><li>Michaelides, E. E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Hydrodynamic+force+and+heat/mass+transfer+from+particles,+bubbles+and+drops+-+the+Freeman+Scholar+Lecture.">Hydrodynamic force and heat/mass transfer from particles, bubbles and drops - the Freeman Scholar Lecture.</a> Journal of Fluids Engineering (AMSE. 125, 209-238 (2003).</li><li>Der Faxen, H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Widerstand+gegen+die+Bewegung+einer+starren+Kugel+in+einer+z&#228;hen+Fl&#252;ssigkeit,+die+zwischen+zwei+parallelen+ebenen+W&#228;nden+eingeschlossen+ist).">Widerstand gegen die Bewegung einer starren Kugel in einer z&#228;hen Fl&#252;ssigkeit, die zwischen zwei parallelen ebenen W&#228;nden eingeschlossen ist).</a> Annalen der Physics. 68, 89-119 (1922).</li><li>Bohlin, T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=On+the+drag+on+a+sphere+moving+in+a+viscous+fluid+inside+a+cylindrical+tube.">On the drag on a sphere moving in a viscous fluid inside a cylindrical tube.</a> Trans Royal Insitute of Technology Stockholm. 155, (1960).</li><li>Miyamura, A., Iwasaki, S., Ishii, T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Experimental+wall+correction+factors+of+single+solid+spheres+in+triangular+and+square+cylinders,+and+parallel+plates.">Experimental wall correction factors of single solid spheres in triangular and square cylinders, and parallel plates.</a> International Journal of Multiphase Flow. 7, 41-46 (1981).</li><li>Tullock, D. L., Phan-Thien, N., Graham, A. L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Boundary+element+simulations+of+spheres+settling+in+circular,+square+and+triangular+ducts.">Boundary element simulations of spheres settling in circular, square and triangular ducts.</a> Rheol. Acta. 31, 139-150 (1992).</li><li>Chhabra, R. P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Wall+effects+on+terminal+velocity+of+non-spherical+particles+in+non-Newtonian+polymer+solutions.">Wall effects on terminal velocity of non-spherical particles in non-Newtonian polymer solutions.</a> Powder Technology. 88, 39-44 (1996).</li><li>Chhabra, R. P., Dekes, D., Chhabra, R. P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Chapter+2.+Wall+effects+on+spheres+falling+axially+in+cylindrical+tubes.">Chapter 2. Wall effects on spheres falling axially in cylindrical tubes.</a> Transport Processes in Bubbles Drops and Particles. , (2002).</li><li>Chhabra, R. P., Francis, S. e. c. o. n. d. e. d. .. ,. T. a. y. l. o. r. &. a. m. p. ;. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> Bubbles, Drops, and Particles in Non-Newtonian Fluids. , (2007).</li><li>Dazhi, G., Tanner, R. I. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+drag+on+a+sphere+in+a+power+law+fluid.">The drag on a sphere in a power law fluid.</a> Journal of Non-Newtonian Fluid Mechanics. 17, 1-12 (1984).</li><li>Tripathi, A., Chhabra, R. P., Sundararajan, T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Power-law+fluid+over+spheroidal+particles.">Power-law fluid over spheroidal particles.</a> Industrial &amp; Engineering Chemistry Research. 33, 403-410 (1994).</li><li>Graham, D. I., Jones, T. E. R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Settling+and+transport+of+spherical+particles+in+power-law+fluids+at+finite+Reynolds+number.">Settling and transport of spherical particles in power-law fluids at finite Reynolds number.</a> Journal of Non-Newtonian Fluid Mechanics. 54, 465-488 (1994).</li><li>Tripathi, A., Chhabra, R. P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Drag+on+spheroidal+particles+in+dilatant+fluids.">Drag on spheroidal particles in dilatant fluids.</a> AIChE. 41 (3), 728-731 (1995).</li><li>Missirlis, K. A., Assimacopoulos, D., Mitsoulis, E., Chhabra, R. P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Wall+effects+for+motion+of+spheres+in+power-law+fluids.">Wall effects for motion of spheres in power-law fluids.</a> Journal of Non-Newtonian Fluid Mechanics. 96 (3), 459-471 (2001).</li><li>Dallon, D. 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> A drag coefficient correlation for spheres settling in Ellis fluids [Ph.D. Dissertation]. , (1967).</li><li>Uhlherr, P. H. T., Le, T. N., Tiu, C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Characterization+of+inelastic+power-law+fluids+using+falling+sphere+data.">Characterization of inelastic power-law fluids using falling sphere data.</a> Canadian Journal of Chemical Engineering. 54, 497-502 (1976).</li><li>Machac, I., Lecjaks, Z. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Wall+Effect+for+a+Sphere+Falling+Through+a+Non-Newtonian+Fluid+in+a+Rectangular+Duct.">Wall Effect for a Sphere Falling Through a Non-Newtonian Fluid in a Rectangular Duct.</a> Chemical Engineering Science. 50 (1), 143-148 (1995).</li><li>Kelessidis, V. C., Mpandelis, G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Measurements+and+prediction+of+terminal+velocity+of+solid+particles+falling+through+stagnant+pseudoplastic+liquids.">Measurements and prediction of terminal velocity of solid particles falling through stagnant pseudoplastic liquids.</a> Powder Technology. 147, 117-125 (2004).</li><li>Shah, S. N., Fadili, Y. E., Chhabra, R. P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=New+model+for+single+spherical+particle+settling+velocity+in+power+law+(visco-inelastic)+fluids.">New model for single spherical particle settling velocity in power law (visco-inelastic) fluids.</a> International Journal of Multiphase Flow. 33, 51-66 (2007).</li><li>Rodrigue, D., DeKee, D., Chan Man Fong, C. F. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+slow+motion+of+a+spherical+particle+in+a+Carreau+fluid.">The slow motion of a spherical particle in a Carreau fluid.</a> Chemical Engineering Communications. 154, 203-215 (1996).</li><li>Darby, 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> Chemical Engineering Fluid Mechanics. , (2001).</li><li>Shah, S. N. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Proppant+settling+correlations+for+non-Newtonian+fluids.">Proppant settling correlations for non-Newtonian fluids.</a> Society of Petroleum Engineers Journal. 22 (2), 164-170 (1982).</li><li>Shah, S. N. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Proppant-settling+correlations+for+non-Newtonian+Fluids.">Proppant-settling correlations for non-Newtonian Fluids.</a> Society of Petroleum Engineers Production Engineering Journal. 1 (6), 446-448 (1986).</li><li>Ford, J. T., Oyeneyin, M. B., 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=The+formulation+of+milling+fluids+for+efficient+hole+cleaning:+an+experimental+investigation.">The formulation of milling fluids for efficient hole cleaning: an experimental investigation.</a> Paper SPE 38819. , (1994).</li><li>Acharya, A., Mashelkar, R. A., Ulbrecht, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Flow+of+inelastic+and+viscoelastic+fluids+past+a+sphere,+Part+II:+Anomalous+separation+in+the+viscoelastic+fluid+flow.">Flow of inelastic and viscoelastic fluids past a sphere, Part II: Anomalous separation in the viscoelastic fluid flow.</a> Rheological Acta. 15, 471-478 (1976).</li><li>Acharya, A. R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Viscoelasticity+of+crosslinked+fracturing+fluids+and+proppant+transport.">Viscoelasticity of crosslinked fracturing fluids and proppant transport.</a> SPE Production Engineering. 3, 483-488 (1988).</li><li>Chhabra, R. P., Uhlherr, P. H. T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Creeping+motion+of+spheres+through+shear-thinning+elastic+fluids+described+by+the+Carreau+viscosity+equation.">Creeping motion of spheres through shear-thinning elastic fluids described by the Carreau viscosity equation.</a> Rheological Acta. 19 (2), 187-195 (1980).</li><li>Bush, M. B., Phan-Thien, N. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Drag+force+on+a+sphere+in+creeping+motion+through+a+Carreau+model+fluid.">Drag force on a sphere in creeping motion through a Carreau model fluid.</a> Journal of Non-Newtonian Fluid Mechanics. 16 (3), 303-313 (1984).</li><li>Broadbent, J. M., Mena, B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Slow+flow+of+an+elastico-viscous+fluid+past+cylinders+and+spheres.">Slow flow of an elastico-viscous fluid past cylinders and spheres.</a> Chemical Engineering Journal. 8, 11-19 (1974).</li><li>Sigli, D., Coutanceau, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Effect+of+finite+boundaries+on+the+slow+laminar+isothermal+flow+of+a+viscoelastic+fluid+around+a+spherical+obstacle.">Effect of finite boundaries on the slow laminar isothermal flow of a viscoelastic fluid around a spherical obstacle.</a> Journal of Non-Newtonian Fluid Mechanics. 2, 1-21 (1977).</li><li>Brule, B. H. A. A. V. D., Gheissary, 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+fluid+elasticity+on+the+static+and+dynamic+settling+of+a+spherical+particle.">Effects of fluid elasticity on the static and dynamic settling of a spherical particle.</a> Journal of Non-Newtonian Fluid Mechanics. 49, 123-132 (1993).</li><li>Walters, K., Tanner, R. I., Chhabra, R. P. . D. e. K. e. e. ,. D. .. ,., DeKee, D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Chapter+3.+The+Motion+of+a+Sphere+through+an+Elastic+Fluid..">Chapter 3. The Motion of a Sphere through an Elastic Fluid..</a> Transport Processes in Bubbles, Drops and Particles. , (1992).</li><li>McKinley, G. H., DeKee, D., Chhabra, R. P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Chapter+14.+Steady+and+transient+motion+of+spherical+particles+in+viscoelastic+liquids.">Chapter 14. Steady and transient motion of spherical particles in viscoelastic liquids.</a> Transport Processes in Bubbles, Drops and Particles. , (2002).</li><li>Chhabra, R. P., Tiu, C., Uhlherr, P. H. T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+study+of+wall+effects+on+the+motion+of+a+sphere+in+viscoelastic+fluids.">A study of wall effects on the motion of a sphere in viscoelastic fluids.</a> Canadian Journal of Chemical Engineering. 59, 771-775 (1981).</li><li>Jones, W. M., Price, A. H., Walters, K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+motion+of+a+sphere+falling+under+gravity+in+a+constant+viscosity+elastic+liquid.">The motion of a sphere falling under gravity in a constant viscosity elastic liquid.</a> Journal of Non-Newtonian Fluid Mechanics. 53, 175-196 (1994).</li><li>Navez, V., Walters, K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+note+on+settling+in+shear-thinning+polymer+solutions.">A note on settling in shear-thinning polymer solutions.</a> Journal of Non-Newtonian Fluid Mechanics. 67, 325-334 (1996).</li><li>Huang, P. Y., Wall Feng, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=effects+on+the+flow+of+viscoelastic+fluids+around+a+circular+cylinder.">effects on the flow of viscoelastic fluids around a circular cylinder.</a> Journal of Non-Newtonian Fluid Mechanics. 60, 179-198 (1995).</li><li>Sugeng, F., Tanner, R. I. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+drag+on+spheres+in+viscoelastic+fluids+with+significant+wall+effects.">The drag on spheres in viscoelastic fluids with significant wall effects.</a> Journal of Non-Newtonian Fluid Mechanics. 20, 281-292 (1986).</li><li>Malhotra, S., Sharma, M. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Settling+of+Spherical+Particles+in+Unbounded+and+Confined+Surfactant-Based+Shear+Thinning+Viscoelastic+Fluids:+An+Experimental+Study.">Settling of Spherical Particles in Unbounded and Confined Surfactant-Based Shear Thinning Viscoelastic Fluids: An Experimental Study.</a> Chemical Engineering Science. 84, 646-655 (2012).</li><li>Zhang, K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Fluids+for+Fracturing+Subterranean+Formations.U.S.">Fluids for Fracturing Subterranean Formations.U.S.</a> US patent. , (2002).</li><li>Gupta, D. V. S., Leshchyshyn, T. T., Hlidek, B. T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Surfactant+gel+foam/emulsions:+History+and+field+application+in+the+western+Canadian+sedimentary+basin.">Surfactant gel foam/emulsions: History and field application in the western Canadian sedimentary basin.</a> , (2005).</li><li>Ferry, J. D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> Viscoelastic Properties of Polymers. , (1970).</li><li>Yesilata, B., Clasen, C., McKinley, G. H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Nonlinear+shear+and+extensional+Flow+dynamics+of+wormlike+surfactant+solutions.">Nonlinear shear and extensional Flow dynamics of wormlike surfactant solutions.</a> Journal of Non-Newtonian Fluid Mechanics. 133, 73-90 (2006).</li></ol>

作者想指出，本出版物的目标是直观地演示测量粒子沉降的实验程序。有关详细结果及分析，读者应参考较早的刊物43。

实验研究的重点是在未受约束和封闭的条件下，测量剪切稀释粘性流体中球形粒子的沉降速度。介绍了详细的实验程序，以获得可重复测量的沉降速度。结果表明，流体弹性可以增加或降低沉降速度。墙体对沉降产生延缓效应，这种效应是用墙体因素来衡量的。
在实验之前，应确保粒子接近表面光滑的完美球体。球体的直径应准确测量。实验过程，包括图像分析，应该通过?...

在药物制造、废水处理、空间推进剂再注入、半导体加工和液体洗涤剂制造等应用中，液体颗粒的悬浮。在石油工业中，粘性压裂液用于在液压断裂中运输质子（通常是砂）。停止抽水后，前体保持断裂打开，并为碳氢化合物回流提供导电途径。
粒子的沉降受流体的流变学和密度、颗粒的大小、形状和密度以及密闭壁的影响的制约。对于在蠕变流系中沉淀在牛顿流体中的球形粒子，沉降速度由斯托克斯方程给出，斯托克斯于 1851 年得出。在随后的研究人员2-6中提出了计算高雷诺兹数字阻力的表达方式。封闭壁通过对粒子施加阻滞作用来降低沉降速度。墙体因子 ，Fw，被定义为在无限制条件下将墙限制在沉降速度的终端沉降速度比率。墙系数量化了密闭墙的阻滞效应。文献7-13提供了许多理论和实验研究，以确定在不同断面管中以不同断面管中沉淀的球体的壁因子。总之，有大量的信息可用于确定牛顿流体中球体的阻力。
过去关于确定非内托输液中颗粒的沉降速度的工作，特别是粘性流体，并不完整。各种数值预测14-18和实验研究19-24可用于文献，以确定在无弹性功率定律流体的球体上的阻力。使用特里帕蒂等人的理论预测。15和特里帕蒂和查布拉17日，雷纳德等人。1开发以下表达式以计算无弹性功率定律流体中的阻力系数（CD）。
对于重新pl<0.1 （爬行流系统）
<img alt="Equation 1" fo:src="/files/ftp_upload/50749/50749eq1highres.jpg" src="/files/ftp_upload/50749/50749eq1.jpg"> 其中 X（n） 是拖动校正因子13。RePL是属于权力法液体中的球体的雷诺兹数字，定义为:
<img alt="Equation 2" fo:src="/files/ftp_upload/50749/50749eq2highres.jpg" src="/files/ftp_upload/50749/50749eq2.jpg"> 其中ρ f是液体的密度。拖动校正因子安装下列方程1:
<img alt="Equation 3" fo:src="/files/ftp_upload/50749/50749eq3highres.jpg" src="/files/ftp_upload/50749/50749eq3.jpg"> 使用拖动系数的定义，将沉降速度计算为:
<img alt="Equation 4" fo:src="/files/ftp_upload/50749/50749eq4highres.jpg" src="/files/ftp_upload/50749/50749eq4.jpg"> 对于 0.1<RePL<100
<img alt="Equation 5" fo:src="/files/ftp_upload/50749/50749eq5highres.jpg" src="/files/ftp_upload/50749/50749eq5.jpg"> 其中 X是表面积与粒子预测面积的比率，球体等于 4。CD0是方程 1给出的斯托克斯区域（rePL < 0.1）的阻力系数，C D∞是牛顿区域的拖动系数值（rePL > 5 x 102），等于 0.44。参数β，b，k表示为:
<img alt="Equations 6-8" fo:src="/files/ftp_upload/50749/50749eq6-8highres.jpg" src="/files/ftp_upload/50749/50749eq6-8.jpg"> αo = 3 和 α 是与 X（n） 相关的平均剪切率的修正如下:
<img alt="Equation 9" fo:src="/files/ftp_upload/50749/50749eq9highres.jpg" src="/files/ftp_upload/50749/50749eq9.jpg"> 要计算沉降速度，使用无维组Nd 25: 
<img alt="Equation 10" fo:src="/files/ftp_upload/50749/50749eq10highres.jpg" src="/files/ftp_upload/50749/50749eq10.jpg"> Nd 独立于沉降速度，可以明确计算。使用这个值和 方程5中的阻力系数表达，可以反复解决RePL。 然后，可以使用:
<img alt="Equation 11" fo:src="/files/ftp_upload/50749/50749eq11highres.jpg" src="/files/ftp_upload/50749/50749eq11.jpg"> 方程1-9中的表达基于对值1≥n≥0.4的理论预测。 查布拉13日将上述表述的预测与沙阿26-27（n变化为0.281-0.762）和福特等人的实验结果进行了比较。 28 （n变化从 0.06-0.29）.这些表达式被证明能够准确预测阻力系数。基于这些分析，上述配方可用于计算无弹性功率定律流体中球形粒子的沉降速度为 1 ≥ n ≥ 0.06。将无弹性功率定律流体的沉降速度与功率定粘液中的实验速度进行比较，以确定流体弹性对沉降速度的影响。下一节中提到了详细的步骤。
测定粘胶液中颗粒的沉降速度也是不同研究人员不同观测的课题:（一） 在爬行流系中，剪切变薄效应完全掩盖粘性效应和沉降速度与纯粘性理论29-32非常一致，（ii） 粒子在爬行流系内外经历阻力减少，由于弹性30，33，34而沉降速度增加，（iii） 沉降速度因流体弹性35而降低。沃尔特斯和坦纳36 总结说，对于博格流体（恒定粘度弹性流体）弹性导致低威森博格数字的阻力减少，其次是在较高的魏森博格数字的阻力增强。麦金利37 强调，球体后的延伸效应导致威森伯格数字的阻力增加。Chhabra13 在对先前在无限制和密闭粘性流体中沉降粒子的工作进行了全面回顾后，强调了在理论发展中结合切变率依赖粘度和流体弹性的现实描述的挑战。在过去几年中，对球形粒子沉降的壁效应的研究也是研究的一个领域。然而，所有的工作都完成了球形粒子在圆柱形管中的沉降。没有关于球形粒子在平行墙体之间沉淀在粘性流体中的数据。
这项工作试图实验研究球体在剪切稀释粘性液体中的沉降。这项实验研究的目的是了解流体弹性、剪切变薄和墙体密闭对剪切稀释粘液中球形粒子沉降速度的影响。本文重点介绍了本研究的实验方法以及一些具有代表性的结果。详细的结果，连同分析，可以在较早的出版物43中找到。

<table border="1">
	<tbody>
		<tr>
			<td>Name of the reagent / equipment</td>
			<td>Company</td>
			<td>Catalogue number</td>
			<td>Comments </td>
		</tr>
		<tr>
			<td>Glass Microspheres</td>
			<td>Whitehouse Scientific</td>
			<td>#GP1750</td>
			<td>Available in different sieve fractions.</td>
		</tr>
		<tr>
			<td>Rheometer</td>
			<td>TA Instruments</td>
			<td>ARES</td>
			<td>Any standard rheometer capable of taking dynamic and static measurements</td>
		</tr>
		<tr>
			<td>Anionic Surfactant (Component A)</td>
			<td></td>
			<td>Proprietary fluid</td>
			<td>Used in oil field services for hydraulic fracturing. Sodium Xylene Sulfonate can be used as a substitute.</td>
		</tr>
		<tr>
			<td>Cationic Surfactant (Component B)</td>
			<td></td>
			<td>Proprietary fluid</td>
			<td>Used in oil field services for hydraulic fractuing. N,N,N-Trimethyl-1-Octadecamonium Chloride can be used as a substitute.</td>
		</tr>
	</tbody>
</table>

experimental measurement of settling velocity of spherical particles in unconfined and confined surfactant-based shear thinning viscoelastic fluids

进行了一项实验性研究，以测量基于表面活性剂的剪切变薄粘性 （VES） 流体中球形粒子的终端沉降速度。测量是针对在平行墙体和平行墙之间的无边界流体和流体中沉淀的粒子进行测量的。VES 流体具有广泛的风湿特性，具有风湿学特征。风湿特征包括稳定的剪切粘度和动态振荡切变测量，分别量化粘度和弹性特性。在无限制条件下的沉降速度以直径至少是颗粒直径25倍的烧嘴来测量。为了测量平行墙之间的沉降速度，构建了两个具有不同墙间距的实验单元。不同大小的球形粒子被轻轻地掉入流体中，并允许沉降。该过程使用高分辨率摄像机进行记录，粒子轨迹使用图像分析软件进行记录。终端沉降速度是根据数据计算的。
通过比较实验沉降速度与 Renaud 等人的无弹性阻力预测计算的沉降速度，可以量化弹性对无边界流体沉降速度的影响 。1结果表明，流体的弹性可以增加或降低沉降速度。减少/增加的幅度是流体的流变特性和粒子特性的函数。观察到封闭壁对沉降造成延缓效应，并根据墙体因素测量阻滞。

实验对七种不同流体混合物中的五种不同直径粒子进行了实验，这些混合物具有独特的K、n和λ值。 图1显示沉降速度作为一个流体中粒子直径的函数。错误栏显示三个测量中的变异性。实验期间测量的室温为23°C。可以观察到，沉降速度随着粒子直径的增加而增加。图 3显示了在 23 °C 的...

Watch this Scientific Journal Video about Experimental Measurement of Settling Velocity of Spherical Particles in Unconfined and Confined Surfactant-based Shear Thinning Viscoelastic Fluids at JoVE.co

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

本文演示了测量表面活性切变粘液中球形粒子终端沉降速度的实验过程。准备了各种风湿特性的流体，并测量了平行壁之间无边界流体和流体中一系列粒子大小的沉降速度。

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 ...

experimental-measurement-settling-velocity-spherical-particles

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Education

JoVE Journal

JoVE Core

Engineering

Physics

Civil Engineering

Unit 1

Fluid Statics

Application of Newton's Laws of Motion

SCIENTISTS IN ACTION

13.2K 次观看.  The University of Texas at Austin. 本文演示了测量表面活性切变粘液中球形粒子终端沉降速度的实验过程。准备了各种风湿特性的流体，并测量了平行壁之间无边界流体和流体中一系列粒子大小的沉降速度。

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

Fabrication of Spatially Confined Complex Oxides

Complex materials such as high Tc superconductors, multiferroics, and colossal magnetoresistors have electronic and magnetic properties that arise from the inherent strong electron correlations that reside within them. These materials can also possess electronic phase separation in which regions of vastly different resistive and magnetic behavior can coexist within a single crystal alloy material. By reducing the scale of these materials to length scales at and below the inherent size of the electronic domains, novel behaviors can be exposed. Because of this and the fact that spin-charge-lattice-orbital order parameters each involve correlation lengths, spatially reducing these materials for transport measurements is a critical step in understanding the fundamental physics that drives complex behaviors. These materials also offer great potential to become the next generation of electronic devices 1-3. Thus, the fabrication of low dimensional nano- or micro-structures is extremely important to achieve new functionality. This involves multiple controllable processes from high quality thin film growth to accurate electronic property characterization. Here, we present fabrication protocols of high quality microstructures for complex oxide manganite devices. Detailed descriptions and required equipment of thin film growth, photo-lithography, and wire-bonding are presented.

We describe the use of pulsed laser deposition (PLD), photolithography and wire-bonding techniques to create micrometer scale complex oxides devices. The PLD is utilized to grow epitaxial thin films. Photolithography and wire-bonding techniques are introduced to create practical devices for measurement purposes.

空间密闭的复合氧化物制备

Complex materials such as high Tc superconductors, multiferroics, and colossal magnetoresistors have electronic and magnetic properties that arise from ...

科研

工程学

Ultrasound Velocity Measurement in a Liquid Metal Electrode

A growing number of electrochemical technologies depend on fluid flow, and often that fluid is opaque. Measuring the flow of an opaque fluid is inherently more difficult than measuring the flow of a transparent fluid, since optical methods are not applicable. Ultrasound can be used to measure the velocity of an opaque fluid, not only at isolated points, but at hundreds or thousands of points arrayed along lines, with good temporal resolution. When applied to a liquid metal electrode, ultrasound velocimetry involves additional challenges: high temperature, chemical activity, and electrical conductivity. Here we describe the experimental apparatus and methods that overcome these challenges and allow the measurement of flow in a liquid metal electrode, as it conducts current, at operating temperature. Temperature is regulated within &#177;2 &#176;C using a Proportional-Integral-Derivative (PID) controller that powers a custom-built furnace. Chemical activity is managed by choosing vessel materials carefully and enclosing the experimental setup in an argon-filled glovebox. Finally, unintended electrical paths are carefully prevented. An automated system logs control settings and experimental measurements, using hardware trigger signals to synchronize devices. This apparatus and these methods can produce measurements that are impossible with other techniques, and allow optimization and control of electrochemical technologies like liquid metal batteries.

Ultrasound velocimetry is used to study mixing by fluid flow in liquid metal electrodes. The focus of this manuscript is to illustrate the methods used for making precise, spatially-resolved ultrasound measurements while limiting oxidation and controlling and monitoring temperature, applied current, and the heater power being supplied.

超声速度测量的液态金属电极

A growing number of electrochemical technologies depend on fluid flow, and often that fluid is opaque. Measuring the flow of an opaque fluid is inherently ...

Development of an Experimental Setup for the Measurement of the Coefficient of Restitution under Vacuum Conditions

The Discrete Element Method is used for the simulation of particulate systems to describe and analyze them, to predict and afterwards optimize their behavior for single stages of a process or even an entire process. For the simulation with occurring particle-particle and particle-wall contacts, the value of the coefficient of restitution is required. It can be determined experimentally. The coefficient of restitution depends on several parameters like the impact velocity. Especially for fine particles the impact velocity depends on the air pressure and under atmospheric pressure high impact velocities cannot be reached. For this, a new experimental setup for free-fall tests under vacuum conditions is developed. The coefficient of restitution is determined with the impact and rebound velocity which are detected by a high-speed camera. To not hinder the view, the vacuum chamber is made of glass. Also a new release mechanism to drop one single particle under vacuum conditions is constructed. Due to that, all properties of the particle can be characterized beforehand.

The coefficient of restitution is a parameter that describes the loss of kinetic energy during collision. Here, a free-fall setup under vacuum conditions is developed to be able to determine the coefficient of restitution parameter for particles in micrometer range with high impact velocities.

实验装置的研制归还系数在真空条件下测量

The Discrete Element Method is used for the simulation of particulate systems to describe and analyze them, to predict and afterwards optimize their ...

Advanced Experimental Methods for Low-temperature Magnetotransport Measurement of Novel Materials

Novel electronic materials are often produced for the first time by synthesis processes that yield bulk crystals (in contrast to single crystal thin film synthesis) for the purpose of exploratory materials research. Certain materials pose a challenge wherein the traditional bulk Hall bar device fabrication method is insufficient to produce a measureable device for sample transport measurement, principally because the single crystal size is too small to attach wire leads to the sample in a Hall bar configuration. This can be, for example, because the first batch of a new material synthesized yields very small single crystals or because flakes of samples of one to very few monolayers are desired. In order to enable rapid characterization of materials that may be carried out in parallel with improvements to their growth methodology, a method of device fabrication for very small samples has been devised to permit the characterization of novel materials as soon as a preliminary batch has been produced. A slight variation of this methodology is applicable to producing devices using exfoliated samples of two-dimensional materials such as graphene, hexagonal boron nitride (hBN), and transition metal dichalcogenides (TMDs), as well as multilayer heterostructures of such materials. Here we present detailed protocols for the experimental device fabrication of fragments and flakes of novel materials with micron-sized dimensions onto substrate and subsequent measurement in a commercial superconducting magnet, dry helium close-cycle cryostat magnetotransport system at temperatures down to 0.300 K and magnetic fields up to 12 T.

We describe the methodology of mechanical exfoliation and deposition of flakes of novel materials with micron-sized dimensions onto substrate, fabrication of experimental device structures for transport experimentation, and the magnetotransport measurement in a dry helium close-cycle cryostat at temperatures down to 0.300 K and magnetic fields up to 12 T.

对于新材料的低温磁输运测量先进的实验方法

Novel electronic materials are often produced for the first time by synthesis processes that yield bulk crystals (in contrast to single crystal thin film ...

Experimental Methods for Investigation of Shape Memory Based Elastocaloric Cooling Processes and Model Validation

Shape Memory Alloys (SMA) using elastocaloric cooling processes have the potential to be an environmentally friendly alternative to the conventional vapor compression based cooling process. Nickel-Titanium (Ni-Ti) based alloy systems, especially, show large elastocaloric effects. Furthermore, exhibit large latent heats which is a necessary material property for the development of an efficient solid-state based cooling process. A scientific test rig has been designed to investigate these processes and the elastocaloric effects in SMAs. The realized test rig enables independent control of an SMA&#39;s mechanical loading and unloading cycles, as well as conductive heat transfer between SMA cooling elements and a heat source/sink. The test rig is equipped with a comprehensive monitoring system capable of synchronized measurements of mechanical and thermal parameters. In addition to determining the process-dependent mechanical work, the system also enables measurement of thermal caloric aspects of the elastocaloric cooling effect through use of a high-performance infrared camera. This combination is of particular interest, because it allows illustrations of localization and rate effects &#8212; both important for efficient heat transfer from the medium to be cooled.
The work presented describes an experimental method to identify elastocaloric material properties in different materials and sample geometries. Furthermore, the test rig is used to investigate different cooling process variations. The introduced analysis methods enable a differentiated consideration of material, process and related boundary condition influences on the process efficiency. The comparison of the experimental data with the simulation results (of a thermomechanically coupled finite element model) allows for better understanding of the underlying physics of the elastocaloric effect. In addition, the experimental results, as well as the findings based on the simulation results, are used to improve the material properties.

Experimental methods for investigation of solid state cooling processes and characterization of elastocaloric material properties of Shape Memory Alloys (SMA) are presented. A custom-built test rig has been designed for controlling and comprehensive monitoring of elastocaloric cooling processes. Furthermore, it provides a validation platform for thermomechanically coupled modeling approaches.

基于形状记忆调查Elastocaloric冷却过程和模型验证实验方法

Shape Memory Alloys (SMA) using elastocaloric cooling processes have the potential to be an environmentally friendly alternative to the conventional vapor ...

Optical Trap Loading of Dielectric Microparticles In Air

We demonstrate a method to trap a selected dielectric microparticle in air using radiation pressure from a single-beam gradient optical trap. Randomly scattered dielectric microparticles adhered to a glass substrate are momentarily detached using ultrasonic vibrations generated by a piezoelectric transducer (PZT). Then, the optical beam focused on a selected particle lifts it up to the optical trap while the vibrationally excited microparticles fall back to the substrate. A particle may be trapped at the nominal focus of the trapping beam or at a position above the focus (referred to here as the levitation position) where gravity provides the restoring force. After the measurement, the trapped particle can be placed at a desired position on the substrate in a controlled manner. 
In this protocol, an experimental procedure for selective optical trap loading in air is outlined. First, the experimental setup is briefly introduced. Second, the design and fabrication of a PZT holder and a sample enclosure are illustrated in detail. The optical trap loading of a selected microparticle is then demonstrated with step-by-step instructions including sample preparation, launching into the trap, and use of electrostatic force to excite particle motion in the trap and measure charge. Finally, we present recorded particle trajectories of Brownian and ballistic motions of a trapped microparticle in air. These trajectories can be used to measure stiffness or to verify optical alignment through time domain and frequency domain analysis. Selective trap loading enables optical tweezers to track a particle and its changes over repeated trap loadings in a reversible manner, thereby enabling studies of particle-surface interaction.

A protocol for launching and stably trapping selected dielectric microparticles in air is presented.

介电微粒的光阱装载在空气中

We demonstrate a method to trap a selected dielectric microparticle in air using radiation pressure from a single-beam gradient optical trap. Randomly ...

Generation of Size-controlled Poly (ethylene Glycol) Diacrylate Droplets via Semi-3-Dimensional Flow Focusing Microfluidic Devices

Uniform and size-controllable poly (ethylene glycol) diacrylate (PEGDA) droplets could be produced via the flow focusing process in a microfluidic device. This paper proposes a semi-three-dimensional (semi-3D) flow-focusing microfluidic chip for droplet formation. The polydimethylsiloxane (PDMS) chip was fabricated using the multi-layer soft lithography method. Hexadecane containing surfactant was used as the continuous phase, and PEGDA with the ultraviolet (UV) photo-initiator was the dispersed phase. Surfactants allowed the local surface tension to drop and formed a more cusped tip which promoted breaking into tiny micro-droplets. As the pressure of dispersed phase was constant, the size of droplets became smaller with increasing continuous phase pressure before dispersed phase flow was broken off. As a result, droplets with size variation from 1 &#181;m to 80 &#181;m in diameter could be selectively achieved by changing the pressure ratio in two inlet channels, and the average coefficient of variation was estimated to be below 7%. Furthermore, droplets could turn into micro-beads by UV exposure for photo-polymerization. Conjugating biomolecules on such micro-beads surface have many potential applications in the fields of biology and chemistry.

Generation of Size-controlled Poly ethylene Glycol Diacrylate Droplets via Semi-3-Dimensional Flow Focusing Microfluidic Devices

Here, we present a protocol to illustrate the fabrication processes and verifying experiments of a semi-three-dimensional (semi-3D) flow-focusing microfluidic chip for droplet formation.

Semi-3-Dimensional 流聚焦微流控装置产生尺寸控制的聚乙二醇二丙烯酸酯液滴

Uniform and size-controllable poly (ethylene glycol) diacrylate (PEGDA) droplets could be produced via the flow focusing process in a microfluidic device. ...

The Diffusion of Passive Tracers in Laminar Shear Flow

A simple method to experimentally observe and measure the dispersion of a passive tracer in a laminar fluid flow is described. The method consists of first injecting fluorescent dye directly into a pipe filled with distilled water and allowing it to diffuse across the cross-section of the pipe to obtain a uniformly distributed initial condition. Following this period, the laminar flow is activated with a programmable syringe pump to observe the competition of advection and diffusion of the tracer through the pipe. Asymmetries in the tracer distribution are studied and correlations between the pipe cross-section and the shape of the distribution is shown: thin channels (aspect ratio &#60;&#60; 1) produce tracers arriving with sharp fronts and tapering tails (front-loaded distributions), while thick channels (aspect ratio ~1) present the opposite behavior (back-loaded distributions). The experimental procedure is applied to capillary tubes of various geometries and is particularly relevant to microfluidic applications by dynamical similarity.

A protocol for the study of the diffusion of passive tracers in laminar pressure-driven flow is presented. The procedure is applicable to various capillary pipe geometries.

无源示踪剂在层流剪切流中的扩散

A simple method to experimentally observe and measure the dispersion of a passive tracer in a laminar fluid flow is described. The method consists of ...

Methods of Ex Situ and In Situ Investigations of Structural Transformations: The Case of Crystallization of Metallic Glasses

We demonstrate the use of two nuclear-based analytical methods that can follow the modifications of microstructural arrangement of iron-based metallic glasses (MGs). Despite their amorphous nature, the identification of hyperfine interactions unveils faint structural modifications. For this purpose, we have employed two techniques that utilize nuclear resonance among nuclear levels of a stable 57Fe isotope, namely M&#246;ssbauer spectrometry and nuclear forward scattering (NFS) of synchrotron radiation. The effects of heat treatment upon (Fe2.85Co1)77Mo8Cu1B14 MG are discussed using the results of ex situ and in situ experiments, respectively. As both methods are sensitive to hyperfine interactions, information on structural arrangement as well as on magnetic microstructure is readily available. M&#246;ssbauer spectrometry performed ex situ describes how the structural arrangement and magnetic microstructure appears at room temperature after the annealing under certain conditions (temperature, time), and thus this technique inspects steady states. On the other hand, NFS data are recorded in situ during dynamically changing temperature and NFS examines transient states. The use of both techniques provides complementary information. In general, they can be applied to any suitable system in which it is important to know its steady state but also transient states.

Methods of Ex Situ and In Situ Investigations of Structural Transformations: The Case of Crystallization of Metallic Glasses

Here, we present a protocol to describe ex situ and in situ investigations of structural transformations in metallic glasses. We employed nuclear-based analytical methods which inspect hyperfine interactions. We demonstrate the applicability of M&#246;ssbauer spectrometry and nuclear forward scattering of synchrotron radiation during temperature-driven experiments.

结构转换的原位和原位研究方法: 金属玻璃结晶的实例

We demonstrate the use of two nuclear-based analytical methods that can follow the modifications of microstructural arrangement of iron-based metallic ...

Cutting Procedures, Tensile Testing, and Ageing of Flexible Unidirectional Composite Laminates

Many body armor designs incorporate unidirectional (UD) laminates. UD laminates are constructed of thin (&#60;0.05 mm) layers of high-performance yarns, where the yarns in each layer are oriented parallel to each other and held in place using binder resins and thin polymer films. The armor is constructed by stacking the unidirectional layers in different orientations. To date, only very preliminary work has been performed to characterize the ageing of the binder resins used in unidirectional laminates and the effects on their performance. For example, during the development of the conditioning protocol used in the National Institute of Justice Standard-0101.06, UD laminates showed visual signs of delamination and reductions in V50, which is the velocity at which half of the projectiles are expected to perforate the armor, after ageing. A better understanding of the material property changes in UD laminates is necessary to comprehend the long-term performance of armors constructed from these materials. There are no current standards recommended for mechanically interrogating unidirectional (UD) laminate materials. This study explores methods and best practices for accurately testing the mechanical properties of these materials and proposes a new test methodology for these materials. Best practices for ageing these materials are also described.

The goal of the study was to develop protocols to prepare consistent specimens for accurate mechanical testing of high-strength aramid or ultra-high-molar-mass polyethylene-based flexible unidirectional composite laminate materials and to describe protocols for performing artificial ageing on these materials.

柔性单向复合层压板的切割程序、拉伸测试和老化

Many body armor designs incorporate unidirectional (UD) laminates. UD laminates are constructed of thin (&#60;0.05 mm) layers of high-performance yarns, ...

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

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