Agradecemos Susantha Wijesinghe que projetou e construiu o sistema de compressão de imagem que usamos. Nós reconhecemos o apoio da DMR-1208990 concessão NSF.

<ol>
	<li>Marcus, G., Parsa, S., Kramel, S., Ni, R., 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=Measurements+of+the+Solid-body+Rotation+of+Anisotropic+Particles+in+3D+Turbulence.">Measurements of the Solid-body Rotation of Anisotropic Particles in 3D Turbulence.</a> New J. Phys. 16, 102001 (2014).</li><li>Bretherton, 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+motion+of+rigid+particles+in+a+shear+flow+at+low+Reynolds+number.">The motion of rigid particles in a shear flow at low Reynolds number.</a> J. Fluid Mech. 14 (02), 284-304 (1962).</li><li>Oullette, N., Xu, H., 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=A+quantitative+study+of+three-dimensional+Lagrangian+particle+tracking+algorithms.">A quantitative study of three-dimensional Lagrangian particle tracking algorithms.</a> Exp. in Fluids. 40 (2), 301-313 (2006).</li><li>Parsa, S., Calzavarini, E., Toschi, F., 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=Rotation+Rate+of+Rods+in+Turbulent+Fluid.">Rotation Rate of Rods in Turbulent Fluid.</a> Phys. Rev. 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. 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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>

Os autores não têm interesses financeiros concorrentes para divulgar.

As medições da vorticidade e rotação de partículas no fluxo de fluido turbulento têm sido reconhecidos como metas importantes em mecânica dos fluidos experimentais. A rotação do corpo sólido de pequenas esferas em turbulência é igual a metade da vorticidade fluido, mas a simetria rotacional de esferas fez a medição directa da sua rotação de corpo sólido difícil. Tradicionalmente, a vorticidade fluido foi medida usando complexo, multi-sensor, hot-wire sondas 14. Mas estes sensores só obter m...

Em recente publicação, que introduziu o uso de partículas feitas a partir de múltiplos braços delgados para medir o movimento rotacional de partículas na turbulência 1. Estas partículas podem ser fabricadas usando impressoras 3D, e é possível medir com precisão a sua posição, orientação e taxa de rotação usando múltiplas câmeras. Usando ferramentas de teoria de corpo delgado, pode ser demonstrado que estas partículas têm elipsóides eficazes 2 correspondente, e os movimentos de rotação destas partículas são idênticos àqueles dos respectivos elipsóides eficazes. Partículas com braços simétricos de comprimento igual giram como esferas. Uma tal partícula é uma tomada, que tem três braços perpendiculares entre si ligado no seu centro. Ajustando os comprimentos relativos dos braços de uma tomada pode formar uma partícula equivalente a qualquer elipsóide triaxial. Se o comprimento de um braço é definida igual a zero, isto cria uma cruz, cujo elipsóide equivalente é um disco. Partículas feitas de delgadobraços ocupam uma pequena fração do volume sólido de suas contrapartes elipsoidais sólidos. Como resultado, eles sedimentam mais lentamente, tornando-os mais fácil de combinar densidade. Isto permite o estudo das partículas muito maiores do que é conveniente, com partículas elipsoidais sólidos. Além disso, a imagem pode ser realizado a concentrações de partículas muito mais elevadas, porque as partículas bloquear uma fracção menor da luz a partir de outras partículas. Neste trabalho, métodos de fabricação e controle de partículas impresso-3D são documentados. Ferramentas para seguir o movimento de translação de partículas esféricas a partir de posições de partículas como pode ser visto por várias câmaras foram desenvolvidas por vários grupos 3,4. Parsa et ai. 5 estendido esta abordagem para rastrear hastes utilizando a posição e orientação das barras visto por várias câmaras. Aqui, nós apresentamos os métodos para a fabricação de partículas de uma larga variedade de formas e reconstruindo as suas orientações em 3D. Isto oferece the possibilidade de alargar o acompanhamento 3D de partículas com formas complexas para uma ampla gama de novas aplicações. Esta técnica tem um grande potencial para o desenvolvimento por causa da grande variedade de formas de partículas que podem ser projetados. Muitas destas formas têm aplicações diretas dos fluxos ambientais, onde plâncton, sementes e cristais de gelo vêm em uma ampla variedade de formas. As ligações entre as rotações de partículas e propriedades fundamentais de pequena escala de escoamentos turbulentos 6 sugerem que o estudo de rotações dessas partículas proporciona novas maneiras de olhar para o processo em cascata turbulento.

<table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always">
	<tbody>
		<tr>
			<td>Condor Nd:YAG 50W 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>Form 1+ 3D printer</td>
			<td>Formlabs</td>
			<td></td>
			<td>Used to make larger particles.</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, 100, 50 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&#8211;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

Métodos experimentais são apresentados para medir o movimento de rotação e de translação de partículas anisotrópicos em fluxos de fluido turbulentos. A tecnologia de impressão 3D é usado para fabricar partículas com braços delgados ligados a um centro comum. Shapes exploradas são cruzes (duas hastes perpendiculares), macacos (três hastes perpendiculares), tríades (três hastes na simetria planar triangular), e tetrads (quatro braços em simetria tetraédrica). Métodos para a produção da ordem de 10.000 partículas tingidos fluorescentemente são descritos. Medições resolvida no tempo da respectiva orientação e taxa de rotação de corpo sólido são obtidos a partir de quatro vídeos sincronizados de seu movimento em um fluxo turbulento entre grades oscilantes com R λ = 91. Neste Reynolds baixo fluxo relativamente número, as partículas advectado são pequenos o suficiente que se aproximem partículas tracer elipsoidais. Nós apresentamos resultados de trajetórias 3D resolvidas no tempo de posição e orientação das partículas comobem como medições das suas velocidades de rotação.

A Figura 3a mostra uma imagem de um tétrade de uma das nossas câmaras acima de uma trama do ângulos de Euler obtido a partir de uma secção da sua trajectória (Figura 3c). Na Figura 3b, os resultados do algoritmo de encontrar orientação, descrito no protocolo 5-5,3, são sobrepostos na imagem de tétrade. Os braços de tétrade na Figura 3a não seguem as distribuições de intensidade simples que são utilizados ...

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.

Métodos para medir a orientação e rotação Taxa de partículas em Turbulência 3D-impressos

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

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10.0K visualizações.  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.

Vídeo: 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.

Encapsulamento e Permeabilidade características das partículas de plasma polimerizados ocas

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

Engenharia

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.

Medição experimental da velocidade de assentamento de partículas esféricas em fluidos viscosticos não confinados e confinados

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.

Automação de Modo de bloqueio em uma rotação do laser da fibra não-linear de polarização através de medidas de polarização de saída

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.

Tridimensional Velocímetro de Partículas de Rastreamento for Applications Turbulência: Case de um fluxo de Jet

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 ...

Frequency Mixing Magnetic Detection Scanner for Imaging Magnetic Particles in Planar Samples

The setup of a planar Frequency Mixing Magnetic Detection (p-FMMD) scanner for performing Magnetic Particles Imaging (MPI) of flat samples is presented. It consists of two magnetic measurement heads on both sides of the sample mounted on the legs of a u-shaped support. The sample is locally exposed to a magnetic excitation field consisting of two distinct frequencies, a stronger component at about 77 kHz and a weaker field at 61 Hz. The nonlinear magnetization characteristics of superparamagnetic particles give rise to the generation of intermodulation products. A selected sum-frequency component of the high and low frequency magnetic field incident on the magnetically nonlinear particles is recorded by a demodulation electronics. In contrast to a conventional MPI scanner, p-FMMD does not require the application of a strong magnetic field to the whole sample because mixing of the two frequencies occurs locally. Thus, the lateral dimensions of the sample are just limited by the scanning range and the supports. However, the sample height determines the spatial resolution. In the current setup it is limited to 2 mm. As examples, we present two 20 mm &#215; 25 mm p-FMMD images acquired from samples with 1 &#181;m diameter maghemite particles in silanol matrix and with 50 nm magnetite particles in aminosilane matrix. The results show that the novel MPI scanner can be applied for analysis of thin biological samples and for medical diagnostic purposes.

A scanner for imaging magnetic particles in planar samples was developed using the planar frequency mixing magnetic detection technique. The magnetic intermodulation product response from the nonlinear nonhysteretic magnetization of the particles is recorded upon a two-frequency excitation. It can be used to take 2D images of thin biological samples.

Frequência mistura Scanner Detecção magnética for Imaging Partículas Magnéticas em amostras Planar

The setup of a planar Frequency Mixing Magnetic Detection (p-FMMD) scanner for performing Magnetic Particles Imaging (MPI) of flat samples is presented. ...

A High Performance Impedance-based Platform for Evaporation Rate Detection

This paper describes the method of a novel impedance-based platform for the detection of the evaporation rate. The model compound hyaluronic acid was employed here for demonstration purposes. Multiple evaporation tests on the model compound as a humectant with various concentrations in solutions were conducted for comparison purposes. A conventional weight loss approach is known as the most straightforward, but time-consuming, measurement technique for evaporation rate detection. Yet, a clear disadvantage is that a large volume of sample is required and multiple sample tests cannot be conducted at the same time. For the first time in literature, an electrical impedance sensing chip is successfully applied to a real-time evaporation investigation in a time sharing, continuous and automatic manner. Moreover, as little as 0.5 ml of test samples is required in this impedance-based apparatus, and a large impedance variation is demonstrated among various dilute solutions. The proposed high-sensitivity and fast-response impedance sensing system is found to outperform a conventional weight loss approach in terms of evaporation rate detection.

This paper presents an impedance-based apparatus for evaporation rate detection of solutions. It offers clear advantages over a conventional weight loss approach: a fast response, high-sensitivity detection, a small sample requirement, multiple sample measurements, and easy disassembly for cleaning and reuse purposes.

A plataforma baseada em alta impedância de desempenho para a detecção Taxa de evaporação

This paper describes the method of a novel impedance-based platform for the detection of the evaporation rate. The model compound hyaluronic acid was ...

Subsurface Defect Localization by Structured Heating Using Laser Projected Photothermal Thermography

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

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

Localização de Defeitos Subsuperficiais por Aquecimento Estruturado usando a Termografia Fototérmica Projetada a Laser

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

A 3D-printed Chamber for Organic Optoelectronic Device Degradation Testing

In this manuscript, we outline the manufacture of a small, portable, easy-to-use atmospheric chamber for organic and perovskite optoelectronic devices, using 3D-printing. As these types of devices are sensitive to moisture and oxygen, such a chamber can aid researchers in characterizing the electronic and stability properties. The chamber is intended to be used as a temporary, reusable, and stable environment with controlled properties (including humidity, gas introduction, and temperature). It can be used to protect air-sensitive materials or to expose them to contaminants in a controlled way for degradation studies. To characterize the properties of the chamber, we outline a simple procedure to determine the water vapor transmission rate (WVTR) using relative humidity as measured by a standard humidity sensor. This standard operating procedure, using a 50% infill density of polylactic acid (PLA), results in a chamber that can be used for weeks without any significant loss of device properties. The versatility and ease of use of the chamber allows it to be adapted to any characterization condition that requires a compact-controlled atmosphere.

Here, we present a protocol for the design, manufacture, and use of a simple, versatile 3D-printed and controlled atmospheric chamber for the optical and electrical characterization of air-sensitive organic optoelectronic devices.

Uma câmara 3D-impresso para orgânicos dispositivo optoeletrônico testes de degradação

In this manuscript, we outline the manufacture of a small, portable, easy-to-use atmospheric chamber for organic and perovskite optoelectronic devices, ...

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.

Métodos de Ex Situ e In Situ investigações de transformações estruturais: O caso de cristalização de vidros metálicos

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

Applicability Analysis of Assessment Methods for Morphological Parameters of Corroded Steel Bars

The irregular and uneven residual sections along the length of a corroded steel bar substantially change its mechanical properties and significantly dominate the safety and performance of an existing concrete structure. As a result, it is important to measure the geometry and amount of corrosion of a steel bar in a structure properly to assess the residual bearing capacity and service life of the structure. This paper introduces and compares five different methods for measuring the geometry and amount of corrosion of a steel bar. A single 500 mm long and 14 mm diameter steel bar is the specimen that is subjected to accelerated corrosion in this protocol. Its morphology and the amount of corrosion were carefully measured before and after using mass loss measurements, a Vernier caliper, drainage measurements, 3D scanning, and X-ray micro-computed tomography (XCT). The applicability and suitability of these different methods were then evaluated. The results show that the Vernier caliper is the best choice for measuring the morphology of a non-corroded bar, while 3D scanning is the most suitable for quantifying the morphology of a corroded bar.

This paper measures the geometry and the amount of corrosion of a steel bar using different methods: mass loss, calipers, drainage measurements, 3D scanning, and X-ray micro-computed tomography (XCT).

Análise da aplicabilidade dos métodos de avaliação de parâmetros morfológicos das barras de aço corroídas

The irregular and uneven residual sections along the length of a corroded steel bar substantially change its mechanical properties and significantly ...