Name: the measurement of unsteady surface pressure using a remote microphone probe
Uploaded: 2016-12-03T13:00:00.000+00:00
Duration: 8 min 53 s
Description: Watch this Scientific Journal Video about The Measurement of Unsteady Surface Pressure Using a Remote Microphone Probe at JoVE.com

This research was made possible through funding from the U.S. Office of Naval Research under Grant No. N000141210337, Deborah Nalchajian and Ronald Joslin.

1.实验准备<ol><li>选择合适的麦克风来构建RMP。感兴趣的频率范围内使用的麦克风的频率范围。 注意:在这个实验中，100和10000赫兹之间的压力波动的兴趣。所选麦克风的测量频率范围是从100到10000赫兹。麦克风的尺寸应尽可能小，虽然有对大小没有具体标准。 </li><li>估计使用附录中描述的分析方法中的制冷剂管理系统的灵敏度和频率响应。调整通过改变管和结构的尺寸的RMP的灵敏度和频率响应。 </li><li>使用的Dremel到0.5 mm内口径不锈钢管切成5.25厘米长的片。 </li><li>用剪刀，剪1.25毫米内径软管到4.75米长的一块。 </li><li>使用铣床一块有机玻璃切成长方体。的长度，宽度，和长方体的高度应2.54厘米，1.27厘米，和1.27厘米，分别。 </li><li>钻孔以0.81 2，2.56，并在有机玻璃支架0.76毫米直径， 如图2所示。 </li><li>用针钻头以使树脂玻璃底座的锥部， 如图2。 </li><li>仰视麦克风灵敏度由制造商提供的说明书中，或使用由黄18介绍的方法校准麦克风。 </li><li>座位麦克风入有机玻璃支架， 如图2，并用环氧树脂固定的麦克风。 </li><li>在不锈钢管和软管连接到有机玻璃底座，并用环氧树脂修复。 </li><li>钻一个直径0.81毫米垂直于模型表面处测量的位置的孔。 </li></ol> 2.实验设置<ol><li>嵌入式安装的主要不锈钢管RMP传感器到模型表面，并添加环氧树脂的不锈钢管固定到相对的模型表面， 如图2。 </li><li>包围声学泡沫的制冷剂管理，以防止寄生噪声污染的系统。 </li><li>路由所有的电线出隧道试验段。 </li><li>路线软消声管出隧道试验段。 </li><li>软消声管的端部连接到压力换能器，以便与不稳定压力同时获得的平均静压的测量。 </li><li>制冷剂管理连接到低噪声放大器和数据采集系统。 </li><li>放大器的增益因子设定为10。注意，可以从壳体改为情况下，增益因子的值。 </li></ol> 3.校准<ol><li>选择一个参考麦克风是高质量和具有频率无关的灵敏度。 </li><li>连接参考微电话到放大器的输入端和所述放大器的输出连接到数据采集系统。 </li><li>同时设置输入增益和放大器至10dB的输出增益。需要注意的是，增益因子可以在不同的测量条件下进行改变。 </li><li>插入基准传声器成活塞发声，如图补充图。 </li><li>打开活塞发声。 </li><li>采集频率为4000赫兹。 </li><li>设定的样本数240,000。 </li><li>获取和保存从参考麦克风输出电压。 </li><li>计算的基准传声器的校准常数。校准常数，C REF，是活塞式制作声压到基准麦克风的电压输出的标准偏差的标准偏差的比率。 </li><li>重复校准处理（步骤3.8和3.9）数次。使用平均值，C REF，作为校准常数。 </li> &lt;li&gt;将参考麦克风垂直于在其上的压力波动被测量， 如图1中的固体表面上。 </li><li>对准RMP自来水参考麦克风的中心。使用参考麦克风和1毫米的RMP抽头之间的距离。 </li><li>放置在靠近测试模型扬声器。使用扬声器和2.5米对于这些测量的麦克风之间的距离。 </li><li>扬声器连接到函数发生器并打开函数发生器。 </li><li>使用该函数发生器的"白噪声"选项，以提供需要的声音信号，并设置均方根电压，V 有效值 ，至0.4V。 </li><li>调整扬声器到最小的体积。 </li><li>打开扬声器。 </li><li>调整扬声器放大器尽可能高的体积而不损坏扬声器。请注意，大多数发言者有一个指示灯警告日E用户如果输出振幅高于扬声器范围。 </li><li>获得和使用40000 Hz的扫描频率为60秒，从两个参考麦克风和RMP的电压输出保存的时间序列数据。 </li><li>计算的声压波动，这是由扬声器和功能发生器产生和由基准麦克风测量的时间序列的值。这仅仅是从基准传声器输出的时间序列电压的乘积， <img alt="公式3" src="/files/ftp_upload/53627/53627eq3.jpg" />和它的校准常数， <img alt="公式4" src="/files/ftp_upload/53627/53627eq4.jpg" /> ; <img alt="公式5" src="/files/ftp_upload/53627/53627eq5.jpg" /> 。注意，该时间序列的声压， <img alt="公式6" src="/files/ftp_upload/53627/53627eq6.jpg" /> ，也是在RMP的自来水压力波动。 </li><li>计算由麦克风在RMP一个测得的时间系列的声压波动<html> S中的时间序列电压输出的产品从贼法牧， <img alt="公式7" src="/files/ftp_upload/53627/53627eq7.jpg" />和麦克风的灵敏度， <img alt="式（8）" src="/files/ftp_upload/53627/53627eq8.jpg" /> ; <img alt="公式9" src="/files/ftp_upload/53627/53627eq9.jpg" /> 。注意，麦克风的灵敏度， <img alt="式（8）" src="/files/ftp_upload/53627/53627eq8.jpg" /> ，应该由制造商提供。 </li><li>计算自动谱密度<img alt="10式" src="/files/ftp_upload/53627/53627eq10.jpg" />的<img alt="11式" src="/files/ftp_upload/53627/53627eq11.jpg" /> 。计算自动谱密度<img alt="12式" src="/files/ftp_upload/53627/53627eq12.jpg" />的<img alt="13式" src="/files/ftp_upload/53627/53627eq13.jpg" /> 。计算交叉谱密度， <img alt="14式" src="/files/ftp_upload/53627/53627eq14.jpg" />之间，.JPG"/&gt;和<img alt="11式" src="/files/ftp_upload/53627/53627eq11.jpg" /> 。自动谱密度和交叉谱密度被Bendat和皮索尔19限定。 </li><li>计算作为传输函数<img alt="15式" src="/files/ftp_upload/53627/53627eq15.jpg" /> 。 </li><li>计算的一致性功能<img alt="16式" src="/files/ftp_upload/53627/53627eq16.jpg" /> ，其中星号表示复共轭。 </li><li>取出参考麦克风。 </li><li>关闭扬声器和函数发生器。 </li><li>卸下扬声器。 </li></ol> 4.数据采集<ol><li>打开风洞。 </li><li>记录时间系列电压输出， <img alt="17式" src="/files/ftp_upload/53627/53627eq17.jpg" /> ，与数据采集系统中的贼法牧。使用40000赫兹的扫描频率。使用采集64秒的持续时间。 </li><li>关闭风洞。 </li></ol><ol><li>计算的声压波动， <img alt="18式" src="/files/ftp_upload/53627/53627eq18.jpg" /> ，通过在RMP麦克风测得<img alt="19式" src="/files/ftp_upload/53627/53627eq19.jpg" /> 。 </li><li>计算自动谱密度<img alt="20式" src="/files/ftp_upload/53627/53627eq20.jpg" />中，表面压力波动作为<img alt="21式" src="/files/ftp_upload/53627/53627eq21.jpg" /> ，其中<img alt="式（22）" src="/files/ftp_upload/53627/53627eq22.jpg" />在声压波动的自谱密度通过在RMP麦克风测量<img alt="18式" src="/files/ftp_upload/53627/53627eq18.jpg" /> 。 </li></ol>

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The authors have nothing to disclose.

The measurement of USP in wind tunnel experiments is needed for many applications related to aeroacoustics and flow-induced vibrations. Compared to existing methods, such as flush-mounted imbedded sensors, PSP, or vibrated membranes, the method described here allows for accurate measurements with a high sensitivity to large-magnitude fluctuation over a wide range of frequencies. More importantly, it also provides a method for USP measurements using a small sensing area that minimizes the spatial averaging effects describ...

物体表面的流体流动通常会导致不稳定和动荡是导致不稳定的表面压力（USP）。流引起的响声和振动往往这个不稳定的直接结果。由散热风扇，螺旋桨，和风力涡轮机产生的辐射声是由相关的USP 1来源为主。的美国专利中湍流的空间和时间特性的测定一般都需要以预测的辐射声音。 美国专利的统计特性中的自动谱密度的形式一般是给定，二点交叉谱密度，和空间相关函数2,3。可以根据不同的应用而变化所需要的频率响应。在许多风洞应用，10kHz至20kHz的响应是足够的。湍流运动的小尺度通常需要感测区域和传感器间距小于1毫米。 EXTEnsive实验研究，以获得湍流诱发压力波动已进行。一个直接的方法是使用嵌入式安装嵌入式传感器。这种方法通常采用的麦克风大型阵列，因为每个传感器只能测量在一个离散点的压力波动。在该方法中使用的典型的传感器是压电换能器，通过高奇4建议。压电式传感器的阵列可以是昂贵的，和测量的频率范围通常是小于10千赫兹。 直接表面安装的麦克风通常用作便宜的USP传感器5。麦克风具有高灵敏度，这是低速流动的显着的益处。然而，这也导致了传感器饱和的风险时的压力大振幅的波动都存在。这种方法是不适合用于大曲率的不连续性，或几何形状过于薄，以包含整个传感器表面。 6。的时间和空间依赖性振动运动进行测量，然后转换为表面用膜的已知机械性能的压力的统计信息。此方法需要仔细的设计，实施和膜的动态响应的精确校准。另外，该振动测量设备，如激光多普勒振动计，是昂贵的。最后，这种方法只能适用于平面。 压敏涂料（PSP）是可用于测量不稳定的表面压力的另一种技术。这种技术需要在透明聚合物粘合剂，这将导致内的分子，因为它们是由特定波长的光照射被激发到更高的能态到待涂覆的表面。随着分子进行氧淬火，能量再在成比例的氧分压的速率，导致发光是成反比的表面压力7租用光。相比麦克风时到PSP方法的主要缺点是在测量的相对低的灵敏度。这限制了PSP相对高速流动的应用。 本通信描述了美国专利，它使用一个远程麦克风探针（RMP）的方法。这种方法首先由英格伦和Richards 8所述。的概念使用连接到表面压力抽头具有中空管的标准微型麦克风。在模型表面上的不稳定压力将行进到在声波的形式油管。管用作"波导"，以允许麦克风，其垂直地安装在管道，以测量声波。波浪然后继续到另一个管足够长，以消除大振幅声řeflections。 英格伦和Richards通过应用和贝赫9 Tijdeman概述确定RMP的动态响应的分析方法。 Perrenes和罗杰·10利用的RMP来衡量过度高扬程设备二维机翼表面的压力。他们开发了一种探针与被连接到一个27厘米长的刚性管经由两个单独的步骤的变化从0.7毫米膨胀至2.5mm表面的直径为0.5mm的毛细管。每一步的变化引起所述管的声阻抗相对大的变化。勒克莱尔和Bohineust 11研究湍流边界层下的墙壁压场。他们使用了一种直径恒定的贼法牧，由弗兰佐尼和Elliott 12的建议。然而，动态响应是只在一个有限的频率范围内足够高。 Arguillat 等人 13设计的制冷剂管理学习发送到车厢内部的噪声。他们测试各个管进行压力变动的麦克风。 Yang等人 14通过使用管道传递函数的方法，它类似于本报告中介绍的方法校正油管失真。 Hoarau 等 15研究了分离区下游的墙压迹。他们设计的RMP有恒定的内径和油管是完全非刚性。 根据先前的研究中，表面压力测量用的RMP获得的精确度主要依赖于该涉及的表面压力到麦克风压力探针的频率依赖传递函数的确定。下面的章节将描述一个贼法牧的几何形状，既简单又有效。实验和分析方法将被引入并为了准确​​地确定制冷剂管理的动态响应验证。该分析模型允许一个贼法牧为Optimized在设计阶段对潜在的广泛的应用范围。 的RMP可以用于在宽的频率范围内测量压力的波动。相对较高的空间分辨率可以提供在空间上分布的不稳定压力场16的特性的详细信息。作为探针小，制冷剂管理可以用来测量在复杂几何形状，如大曲率或有限间距17压力波动。此外，连接表面抽头和麦克风传感器管可以在麦克风减小感应压力波动的幅度。因此，RMP传感器的几何形状和参数的合理设计产生获得相对于嵌入式安装，直接将话筒模型表面时有显著较少限制USP特征的方法。 制冷剂管理的RMPThe一般结构的结构图1中示出</strong&gt;的信息。制冷剂管理由一个管从模型表面导致的膨胀部，并从该扩大部分延伸到第二管的"摇篮"。然后，第三管被连接到充当消声终止。摇篮是用于房屋麦克风和管连接的机械加工的塑料部件。制冷剂管理结构的细节可以为各种实验条件进行调整。第二，大径管的目的是允许的相对笨重的麦克风和支架进一步来自USP测量点被放置而不显著降低测量灵敏度。如果它不是必要该第二管可被消除，并扩大部分可以建在摇篮。消声终止制成的软塑料，这是大约2到3米的长度。 对于本演示中，贼法牧的设计是为表面压力波动的测量浊度下优化ulent 如图2所示边界层没有流向压力梯度，该第二管被淘汰了。观察到所述第一管的两种不同长度的影响。第一管从不锈钢制成具有0.5mm的内径和0.81毫米的外径。第一管的长度分别为5.35和10.40厘米分别。扩大部分，将其掺入支架的入口的内径，为0.5mm，和出口的内径为1.25毫米，这是相同的耗散终止的内径。扩大部分的角为7°。有在直径1.25毫米托架为了平稳地展开部与消声终止连接的孔。传感区域通过一个垂直0.75毫米孔连接到1.25毫米的孔。

<table><tbody><tr><td>Microphone</td><td>ACO Pacific (http://www.acopacific.com/)</td><td>7016</td><td>Used to measure the sound pressure and calibrate the RMP as a reference.</td></tr><tr><td>Microphone</td><td>Knowles (http://www.knowles.com/eng)</td><td>FG-23629-C36</td><td>Used to measure the pressure fluctuation as a part of the RMP.</td></tr><tr><td>Microbore Tubing</td><td>Saint-gobain (http://www.biopharm.saint-gobain.com/en/index.asp)</td><td>Tygon ND 100-80</td><td>Used to dissipate the sound waves as a dissipation termination.</td></tr><tr><td>Hypodermic Tubing</td><td>MicroGroup (http://www.microgroup.com/)</td><td>304H21RW</td><td>Used to connect the surface tap and allow the surface pressure fluctuation to convect to the microphone in the RMP in the form of sound.</td></tr><tr><td>Hypodermic Tubing</td><td>MicroGroup (http://www.microgroup.com/)</td><td>304H14H</td><td>Used to reduce the dissipative effect and allow the surface pressure fluctuation to convect to the microphone in the RMP in the form of sound.</td></tr><tr><td>plexiglass</td><td>Plaskolite (http://www.plaskolite.com/)</td><td>1X76204A</td><td>Used to make cradles which can connect the tubing and the microphone for the RMP.</td></tr><tr><td>Data acquisition chassis</td><td>National Instruments (http://www.ni.com/)</td><td>PXI-1006</td><td>For data acquisition.</td></tr><tr><td>Data acquisition channel</td><td>National Instruments (http://www.ni.com/)</td><td>PXI-4472</td><td>For data acquisiton.</td></tr><tr><td>Function generator</td><td>thinkSRS (http://www.thinksrs.com/)</td><td>DS360</td><td>To generate white noise signal.</td></tr><tr><td>Pistonphone</td><td>B&amp;amp;K (http://www.bksv.com/)</td><td>4228</td><td>To generate sine waves with constant frequency which will be used to calibrate the reference microphone.</td></tr><tr><td>Loudspeaker</td><td>Mackie (http://www.mackie.com/index.html)</td><td>HD1531</td><td>Used to convert the electrical white noise signal into sound. It is the sound source for calibrating the RMP.</td></tr><tr><td>MatLab</td><td>Mathworks (http://www.mathworks.com/)</td><td></td><td>Used to process experimental data.</td></tr><tr><td>LabVIEW</td><td>National Instruments (http://www.ni.com/)</td><td></td><td>Used control the hardware for data acquisition and record the data.</td></tr></tbody></table>

the measurement of unsteady surface pressure using a remote microphone probe

Microphones are widely applied to measure pressure fluctuations at the walls of solid bodies immersed in turbulent flows. Turbulent motions with various characteristic length scales can result in pressure fluctuations over a wide frequency range. This property of turbulence requires sensing devices to have sufficient sensitivity over a wide range of frequencies. Furthermore, the small characteristic length scales of turbulent structures require small sensing areas and the ability to place the sensors in very close proximity to each other. The complex geometries of the solid bodies, often including large surface curvatures or discontinuities, require the probe to have the ability to be set up in very limited spaces. The development of a remote microphone probe, which is inexpensive, consistent, and repeatable, is described in the present communication. It allows for the measurement of pressure fluctuations with high spatial resolution and dynamic response over a wide range of frequencies. The probe is small enough to be placed within the interior of typical wind tunnel models. The remote microphone probe includes a small, rigid, and hollow tube that penetrates the model surface to form the sensing area. This tube is connected to a standard microphone, at some distance away from the surface, using a "T" junction. An experimental method is introduced to determine the dynamic response of the remote microphone probe. In addition, an analytical method for determining the dynamic response is described. The analytical method can be applied in the design stage to determine the dimensions and properties of the RMP components.

从两个有代表性的RMP设计标定结果显示在本节。第一个使用的5.35厘米主管，而第二个用于一个10.4厘米主管。耗散终端是4.75米长为制冷剂管理计划。 通过在RMP和由基准传声器的传声器测量的压力的波动之间的一致性示于图3。数据显示在一个宽的频率范围内的近统一相干值。在频率在10kHz以上，相干普遍居高不下，...

Watch this Scientific Journal Video about The Measurement of Unsteady Surface Pressure Using a Remote Microphone Probe at JoVE.com

The Measurement of Unsteady Surface Pressure Using a Remote Microphone Probe

Here, we present a protocol to measure, with high spatial resolution, the unsteady surface pressure in turbulent flows. This method demonstrates the construction of a remote microphone probe (RMP) and the determination of its frequency-dependent, complex transfer function. An analytical determination of the dynamic response is presented and validated.

非定常表面压力的使用远程麦克风探头测量

Microphones are widely applied to measure pressure fluctuations at the walls of solid bodies immersed in turbulent flows. Turbulent motions with various ...

the-measurement-unsteady-surface-pressure-using-remote-microphone

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Fluid Properties

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6.9K 次观看.  University of Notre Dame. Here, we present a protocol to measure, with high spatial resolution, the unsteady surface pressure in turbulent flows. This method demonstrates the construction of a remote microphone probe (RMP) and the determination of its frequency-dependent, complex transfer function. An analytical determination of the dynamic response is presented and validated.

视频: The Measurement of Unsteady Surface Pressure Using a Remote Microphone Probe

Exploring the Effects of Atmospheric Forcings on Evaporation: Experimental Integration of the Atmospheric Boundary Layer and Shallow Subsurface

Evaporation is directly influenced by the interactions between the atmosphere, land surface and soil subsurface. This work aims to experimentally study evaporation under various surface boundary conditions to improve our current understanding and characterization of this multiphase phenomenon as well as to validate numerical heat and mass transfer theories that couple Navier-Stokes flow in the atmosphere and Darcian flow in the porous media. Experimental data were collected using a unique soil tank apparatus interfaced with a small climate controlled wind tunnel. The experimental apparatus was instrumented with a suite of state of the art sensor technologies for the continuous and autonomous collection of soil moisture, soil thermal properties, soil and air temperature, relative humidity, and wind speed. This experimental apparatus can be used to generate data under well controlled boundary conditions, allowing for better control and gathering of accurate data at scales of interest not feasible in the field. Induced airflow at several distinct wind speeds over the soil surface resulted in unique behavior of heat and mass transfer during the different evaporative stages.

A protocol for the design and construction of a soil tank interfaced to a small climate controlled wind tunnel to study the effects of atmospheric forcings on evaporation is presented. Both the soil tank and wind tunnel are instrumented with sensor technologies for the continuous in situ measurement of environmental conditions.

在探索大气蒸发强迫的影响:大气边界层和浅地层的实验整合

Evaporation is directly influenced by the interactions between the atmosphere, land surface and soil subsurface. This work aims to experimentally study ...

科研

环境科学

Blast Quantification Using Hopkinson Pressure Bars

Near-field blast load measurement presents an issue to many sensor types as they must endure very aggressive environments and be able to measure pressures up to many hundreds of megapascals. In this respect the simplicity of the Hopkinson pressure bar has a major advantage in that while the measurement end of the Hopkinson bar can endure and be exposed to harsh conditions, the strain gauge mounted to the bar can be affixed some distance away. This allows protective housings to be utilized which protect the strain gauge but do not interfere with the measurement acquisition. The use of an array of pressure bars allows the pressure-time histories at discrete known points to be measured. This article also describes the interpolation routine used to derive pressure-time histories at un-instrumented locations on the plane of interest. Currently the technique has been used to measure loading from high explosives in free air and buried shallowly in various soils.

This protocol details the use of Hopkinson pressure bars to measure reflected blast loading from near-field explosive events. It is capable of interpolating a pressure-time history at any point on a reflective boundary and as such can be used to fully characterize the spatial and temporal variations in loading produced.

高炉利用定量霍普金森杆

Near-field blast load measurement presents an issue to many sensor types as they must endure very aggressive environments and be able to measure pressures ...

工程学

Investigating the Three-dimensional Flow Separation Induced by a Model Vocal Fold Polyp

The fluid-structure energy exchange process for normal speech has been studied extensively, but it is not well understood for pathological conditions. Polyps and nodules, which are geometric abnormalities that form on the medial surface of the vocal folds, can disrupt vocal fold dynamics and thus can have devastating consequences on a patient&#39;s ability to communicate. Our laboratory has reported particle image velocimetry (PIV) measurements, within an investigation of a model polyp located on the medial surface of an in&#160;vitro driven vocal fold model, which show that such a geometric abnormality considerably disrupts the glottal jet behavior. This flow field adjustment is a likely reason for the severe degradation of the vocal quality in patients with polyps. A more complete understanding of the formation and propagation of vortical structures from a geometric protuberance, such as a vocal fold polyp, and the resulting influence on the aerodynamic loadings that drive the vocal fold dynamics, is necessary for advancing the treatment of this pathological condition. The present investigation concerns the three-dimensional flow separation induced by a wall-mounted prolate hemispheroid with a 2:1 aspect ratio in cross flow, i.e. a model vocal fold polyp, using an oil-film visualization technique. Unsteady, three-dimensional flow separation and its impact of the wall pressure loading are examined using skin friction line visualization and wall pressure measurements.

Vocal fold polyps can disrupt vocal fold dynamics and thus can have devastating consequences on a patient&#39;s ability to communicate. Three-dimensional flow separation induced by a wall-mounted model polyp and its impact on the wall pressure loading are examined using particle image velocimetry, skin friction line visualization, and wall pressure measurements.

研究模型声乐折叠聚合物引起的三维流量分离

The fluid-structure energy exchange process for normal speech has been studied extensively, but it is not well understood for pathological conditions. ...

生物工程

Manufacturing Simple and Inexpensive Soil Surface Temperature and Gravimetric Water Content Sensors

Quantifying temperature and moisture at the soil surface is essential for understanding how soil surface biota respond to changes in the environment. However, at the soil surface these variables are highly dynamic and standard sensors do not explicitly measure temperature or moisture in the upper few millimeters of the soil profile. This paper describes methods for manufacturing simple, inexpensive sensors that simultaneously measure the temperature and moisture of the upper 5 mm of the soil surface. In addition to sensor construction, steps for quality control, as well as for calibration for various substrates, are explained. The sensors incorporate a Type E thermocouple to measure temperature and assess soil moisture by measuring the resistance between two gold-plated metal probes at the end of the sensor at a depth of 5 mm. The methods presented here can be altered to customize probes for different depths or substrates. These sensors have been effective in a variety of environments and have endured months of heavy rains in tropical forests as well as intense solar radiation in deserts of the southwestern U.S. Results demonstrate the effectiveness of these sensors for evaluating warming, drying, and freezing of the soil surface in a global change experiment.

Accurately measuring temperature and water content of the upper 5 mm of the soil surface can improve our understanding of environmental controls on biological, chemical, and physical processes. Here we describe a protocol for manufacturing, calibrating, and conducting measurements with soil surface temperature and moisture sensors.

制造简单、廉价的土壤表面温度和重力含水量传感器

Quantifying temperature and moisture at the soil surface is essential for understanding how soil surface biota respond to changes in the environment. ...

Measurements of Waves in a Wind-wave Tank Under Steady and Time-varying Wind Forcing

This manuscript describes an experimental procedure that allows obtaining diverse quantitative information on temporal and spatial evolution of water waves excited by time-dependent and steady wind forcing. Capacitance-type wave gauge and Laser Slope Gauge (LSG) are used to measure instantaneous water surface elevation and two components of the instantaneous surface slope at a number of locations along the test section of a wind-wave facility. The computer-controlled blower provides airflow over the water in the tank whose rate can vary in time. In the present experiments, the wind speed in the test section initially increases quickly from rest to the set value. It is then kept constant for the prescribed duration; finally, the airflow is shut down. At the beginning of each experimental run, the water surface is calm and there is no wind. Operation of the blower is initiated simultaneously with the acquisition of data provided by all sensors by a computer; data acquisition continues until the waves in the tank fully decay. Multiple independent runs performed under identical forcing conditions allow determining statistically reliable ensemble-averaged characteristic parameters that quantitatively describe wind-waves&#39; variation in time for the initial development stage as a function of fetch. The procedure also allows characterizing the spatial evolution of the wave field under steady wind forcing, as well as decay of waves in time, once the wind is shut down, as a function of fetch.

This manuscript describes a fully computer-controlled procedure that allows obtaining reliable statistical parameters from experiments of water waves excited by steady and unsteady wind forcing in a small-scale facility.

稳定时变风强迫下风浪罐中波浪的测量

This manuscript describes an experimental procedure that allows obtaining diverse quantitative information on temporal and spatial evolution of water ...

Measurement of Spatial Stability in Precision Grip

The purpose of the protocol is to indirectly evaluate the direction of the finger force during manipulation of a handheld object based on the biomechanical relationships in which deviated force direction causes center of pressure (COP) replacement. To evaluate this, a thin, flexible, and high spatial resolution pressure sensor sheet is used. The system allows measurement of the COP trajectory in addition to the force amplitude and its temporal regulation. A series of experiments found that increased trajectory length reflected a sensorimotor deficit in stroke patients, and that decreased COP trajectory reflects a compensatory strategy to avoid an object slipping from the hand grip in the elderly. Moreover, the COP trajectory could also be decreased by dual task interference. This article describes the experimental procedure and discusses how finger COP contributes to an understanding of the physiology and pathophysiology of grasping.

The goal of this protocol is to measure the center of pressure (COP) replacement using a high spatial resolution sensor sheet to reflect the spatial stability in a precision grip. The use of this protocol could contribute to greater understanding of the physiology and pathophysiology of grasping.

精密握把空间稳定性的测量

The purpose of the protocol is to indirectly evaluate the direction of the finger force during manipulation of a handheld object based on the ...

行为学

Mechano-Node-Pore Sensing: A Rapid, Label-Free Platform for Multi-Parameter Single-Cell Viscoelastic Measurements

Cellular mechanical properties are involved in a wide variety of biological processes and diseases, ranging from stem cell differentiation to cancer metastasis. Conventional methods for measuring these properties, such as atomic force microscopy (AFM) and micropipette aspiration (MA), capture rich information, reflecting a cell's full viscoelastic response; however, these methods are limited by very low throughput. High-throughput approaches, such as real-time deformability cytometry (RT-DC), can only measure limited mechanical information, as they are often restricted to single-parameter readouts that only reflect a cell's elastic properties. In contrast to these methods, mechano-node-pore sensing (mechano-NPS) is a flexible, label-free microfluidic platform that bridges the gap in achieving multi-parameter viscoelastic measurements of a cell with moderate throughput. A direct current (DC) measurement is used to monitor cells as they transit a microfluidic channel, tracking their size and velocity before, during, and after they are forced through a narrow constriction. This information (i.e., size and velocity) is used to quantify each cell's transverse deformation, resistance to deformation, and recovery from deformation. In general, this electronics-based microfluidic platform provides multiple viscoelastic cell properties, and thus a more complete picture of a cell's mechanical state. Because it requires minimal sample preparation, utilizes a straightforward electronic measurement (in contrast to a high-speed camera), and takes advantage of standard soft lithography fabrication, the implementation of this platform is simple, accessible, and adaptable to downstream analysis. This platform's flexibility, utility, and sensitivity have provided unique mechanical information on a diverse range of cells, with the potential for many more applications in basic science and clinical diagnostics.

Presented here is a method to mechanically phenotype single cells using an electronics-based microfluidic platform called mechano-node-pore sensing (mechano-NPS). This platform maintains moderate throughput of 1-10 cells/s while measuring both the elastic and viscous biophysical properties of cells.

机械节点孔传感:用于多参数单细胞粘弹性测量的快速、无标记平台

Cellular mechanical properties are involved in a wide variety of biological processes and diseases, ranging from stem cell differentiation to cancer ...

定制的压力传感器系统，用于记录非营养性吸吮爆发

Non-Nutritive Suck Parameters Measurements Using a Custom Pressure Transducer System

The non-nutritive suck (NNS) device is a transportable, user-friendly pressure transducer system that quantifies infants' NNS behavior on a pacifier. Recording and analysis of the NNS signal using our system can provide measures of an infant's NNS burst duration (s), amplitude (cmH2O), and frequency (Hz). Accurate, reliable, and quantitative assessment of NNS has immense value in serving as a biomarker for future feeding, speech-language, cognitive, and motor development. The NNS device has been used in numerous research lines, some of which have included measuring NNS features to investigate the effects of feeding-related interventions, characterizing NNS development across populations, and correlating sucking behaviors with subsequent neurodevelopment. The device has also been used in environmental health research to examine how exposures in utero can influence infant NNS development. Thus, the overarching goal in research and clinical utilization of the NNS device is to correlate NNS parameters with neurodevelopmental outcomes to identify children at risk for developmental delays and provide rapid early intervention.

作者聚焦:非营养性吸吮对言语出现和婴儿发育的影响

The non-nutritive suck (NNS) device can easily collect and quantify NNS features using a pacifier connected to a pressure transducer and recorded through a data acquisition system and laptop. Quantification of NNS parameters can provide valuable insight into a child's current and future neurodevelopment.

使用定制压力传感器系统测量非营养性吸吮参数

The non-nutritive suck (NNS) device is a transportable, user-friendly pressure transducer system that quantifies infants' NNS behavior on a pacifier. ...

非定常表面压力的使用远程麦克风探头测量

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