Ce travail a été soutenu par le programme Young Investigator AFOSR sous FA9550-12-1-0352 et un Prix 3M de la faculté non permanent. Les auteurs tiennent à remercier lalisa Stutts et Janine Tom de discussion utile relative à ce projet. Les auteurs remercient le Centre de Microscopie Calit2 et pour la spectroscopie laser à l&#39;Université de Californie, Irvine pour permettre l&#39;utilisation de ses installations. Hodge Harland et l&#39;UCI Sciences physiques Atelier d&#39;usinage sont reconnus pour la fabrication d&#39;outils. Poly (lactique) de fibres d&#39;acide a été généreusement fourni par Teijin monofilament.

1. Catalyser fibres sacrifiées <ol><li> Enrouler la quantité désirée de fibres de poly (lactique), d&#39;acide près de la partie inférieure de la broche ¾ personnalisée. Réduire le chevauchement de fibres pour fournir l&#39;exposition maximale de la surface. </li><li> Mélanger déminéralisée H 2 O avec 40 ml de Disperbyk 130 dans une bouteille fermée et secouer jusqu&#39;à ce qu&#39;une solution homogène. Ensuite, placez un bécher de 1000 dans un bain d&#39;eau à 37 ° C et verser trifluoréthanol dans le bécher. La quantité de H 2 O et TFE à utiliser dépend du diamètre de la fibre PLA utilisé. <table border="1"><tbody><tr><td> Diamètre de la fibre </td><td> Quantité de H 2 O (ml) </td><td> Montant de TFE (ml) </td></tr><tr><td> 200 </td><td> 400 </td><td> 400 </td></tr><tr><td> 300 </td><td> 360 </td><td> 440 </td></tr><tr><td> 500 </td><td> 320 </td><td> 480 </td></tr></tbody></table></li><li> Ajouterl&#39;O / Disperbyk 187 solution H 2 dans le bécher et remuer jusqu&#39;à homogénéité. </li><li> Ajouter 1 g de vert de malachite dans le mélange et remuer jusqu&#39;à dissolution. </li><li> Placez la broche sur mesure avec des fibres dans le bécher ½ pouce du fond et fixer la broche à une console de mixage numérique. Puis, vous lancez le mélangeur numérique à 400 rpm. </li><li> Ajouter lentement 1,3 g de catalyseur à l&#39;étain (II) oxalate (SnOx) au mélange. L&#39;ajout de SnOx doit être progressive afin d&#39;éviter les grandes agglomérations de matériel de s&#39;écraser sur la solution. </li><li> Ajuster le pH dans le mélange avec du NaOH jusqu&#39;à pH ~ 6,8-7,2. </li><li> Fixer un couvercle sur le bécher et augmenter la rotation de la broche à 500 tours par minute pendant 24 heures. Si une agglomération de SnOx est observée, casser manuellement vers le haut dans les 2 premières heures. </li><li> Retirer la broche et sèche au four à 35 ° C pendant la nuit. </li><li> Déballer et enlever l&#39;excès de catalyseur à partir des fibres de PLA catalysées. </li></ol> 2. Microvasculaire gaz Exchange Unité Fabrication <ol><li> Procurez-vous une paire de cuivre plaques de laiton de motifs découpés au laser avec le motif de microvasculaire souhaitée et fixer les plaques sur les détenteurs de clip. </li><li> Couper une longueur de 10 pouces de fibre catalysée par micro-canal et supprimer n&#39;importe quel catalyseur restant à l&#39;aide d&#39;une plaque plus épaisse pour réduire le diamètre des fibres (plaque nuls). </li><li> Cône les bords des fibres à l&#39;aide de la pointe d&#39;un pistolet à colle chaude pour extruder lentement les bouts de fibre. </li><li> Passer les fibres à travers des trous correspondant à des paires de plaques de mise en forme de laiton. </li><li> Visser les plaques sur une boîte de moulage. Assurez-vous que les fibres ne sont pas tordus lors de la fixation des plaques. </li><li> Enchaîner les conseils de fibre à travers le tuning pegs du conseil de tension personnalisé. </li><li> Tendre les fibres PLA jusqu&#39;à tendue. Faites attention de ne pas trop la tension et enclenchez les fibres. </li><li> Enlever les particules en excès à partir du motif de la fibre à l&#39;aide d&#39;air comprimé. </li><li> Mix polydiméthylsiloxane base (PDMS) avec durcisseur en 10:1, v: rapport v. </li&gt; <li> Degas le mélange sous vide dans un bocal en dessiccateur pendant 10 min. </li><li> Verser le mélange PDMS dans la boîte de moule. Ne pas verser directement sur les fibres, afin de réduire le piégeage de bulles d&#39;air. </li><li> Utilisation d&#39;une aiguille de calibre 26, éliminer les bulles à l&#39;intérieur de la boîte de moulage, ou entre les fibres. </li><li> Durcir le mélange PDMS à 85 ° C pendant 30 min. </li><li> Détachez les plaques d&#39;airain de la boîte de moule, en veillant à ne pas plier les plaques ou tirer trop fort. Retirez la 1 ère étape guéri de la boîte de moule. </li><li> Passer les fibres à travers un bouchon RTV en perforant des trous dans le bouchon avec une aiguille hypodermique. En fonction de la taille des fibres, en utilisant une jauge d&#39;aiguille qui a au moins 2 fois le diamètre intérieur du diamètre externe de la fibre. Maintenir une configuration similaire à celle de la plaque de formation de motifs en laiton, mais plus largement étalé. </li><li> Fixer les embouts aux extrémités d&#39;une boîte de moule plus grand et verser une 2 ème étape du PDMS. </li><li> Retirez toutes les bulles de gaz restants etdurcir à 85 ° C pendant 30 min. </li><li> Coupez les fibres PLA excès de l&#39;échantillon et le placer dans un four sous vide à 210 ° C pendant 24 heures, ou jusqu&#39;à ce que les fibres de PLA ont été pour la plupart évacués. </li><li> Si l&#39;APL ne peut être retiré, dissoudre doucement sur les microcanaux en utilisant une injection de 1 ml de chloroforme. </li></ol>

<ol>
	<li>Bellan, L. M., Singh, S. P., Henderson, P. W., Porri, T. J., Craighead, H. G., Spector, J. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Fabrication+of+an+artificial+3-dimensional+vascular+network+using+sacrificial+sugar+structures.">Fabrication of an artificial 3-dimensional vascular network using sacrificial sugar structures.</a> Soft Matter. 5 (7), 1354 (2009).</li><li>Bellan, L. M., Strychalski, E. A., Craighead, H. G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Nano-channels+fabricated+in+polydimethylsiloxane+using+sacrificial+electrospun+polyethylene+oxide+nanofibers.">Nano-channels fabricated in polydimethylsiloxane using sacrificial electrospun polyethylene oxide nanofibers.</a> J. Vac. Sci. Technol. B Microelectron. Nanometer Struct. Process. Meas. Phenom. 26 (5), 1728 (2008).</li><li>Borenstein, J. T., Weinberg, E. J., Orrick, B. K., Sundback, C., Kaazempur-Mofrad, M. R., Vacanti, J. P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Microfabrication+of+three-dimensional+engineered+Scaffolds.">Microfabrication of three-dimensional engineered Scaffolds.</a> Tissue Eng. 13 (8), 1837-1844 (2007).</li><li>Wu, H., Odom, T. W., Chiu, D. T., Whitesides, G. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Fabrication+of+complex+three-dimensional+microchannel+systems+in+PDMS.">Fabrication of complex three-dimensional microchannel systems in PDMS.</a> J. Am. Chem. Soc. 125 (2), 554-559 (2003).</li><li>Trask, R. S., Bond, I. P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Biomimetic+self-healing+of+advanced+composite+structures+using+hollow+glass+fibres.">Biomimetic self-healing of advanced composite structures using hollow glass fibres.</a> Smart Mater. Struct. 15 (3), 704-710 (2006).</li><li>Dong, H., Esser-Kahn, A. P., 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=Chemical+treatment+of+poly(lactic+acid)+fibers+to+enhance+the+rate+of+thermal+depolymerization.">Chemical treatment of poly(lactic acid) fibers to enhance the rate of thermal depolymerization.</a> ACS Appl. Mater. Interfaces. 4 (2), 503-509 (2012).</li><li>Esser-Kahn, A. P., Thakre, P. 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=Three-dimensional+microvascular+fiber-reinforced+composites.">Three-dimensional microvascular fiber-reinforced composites.</a> Adv. Mater. 23 (32), 3654-3658 (2011).</li><li>White, S. R., Blaiszik, B. J., Kramer, S. L. B., Olugebefola, S. C., Moore, J. S., Sottos, N. R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Self-healing+polymers+and+composites.">Self-healing polymers and composites.</a> Am. Sci. 99 (5), 392 (2011).</li><li>Nguyen, D. T., Leho, Y. T., Esser-Kahn, A. 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+three-dimensional+microvascular+gas+exchange+unit+for+carbon+dioxide+capture.">A three-dimensional microvascular gas exchange unit for carbon dioxide capture.</a> Lab Chip. 12 (7), 1246 (2012).</li><li>Nguyen, D. T., Leho, Y. T., Esser-Kahn, A. P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+effect+of+membrane+thickness+on+a+microvascular+gas+exchange+unit.">The effect of membrane thickness on a microvascular gas exchange unit.</a> Adv. Funct. Mater. , (2012).</li></ol>

Nous avons déposé une demande de brevet provisoire sur cette technologie und brevet américain US application provisoire de série n ° 61/590, 086.

L&#39;introduction du catalyseur SnOx dans les fibres PLA permet aux fibres de dépolymérisent à une température inférieure. Ceci permet d&#39;éviter la dégradation de la résine d&#39;enrobage, dans ce cas, le PDMS. Une broche de commande est nécessaire de bien mélanger la solution de traitement (figure 5A). L&#39;axe est composé de six tiges de support autour d&#39;un noyau central qui se fixe à un mélangeur numérique. Les fibres sont enroulés autour des tiges de support de telle sorte qu...

Les systèmes naturels utilisent de vastes réseaux vasculaires de faciliter de nombreuses fonctions biologiques. le transport de masse peut être réalisé efficacement dans de tels systèmes en raison d&#39;une grande surface de rapports de volume et les structures d&#39;emballage optimisés. Alors que de nombreuses techniques de fabrication synthétiques peuvent produire des structures microvasculaires, nul ne peut produire microvasculature à grande échelle tout en maintenant la complexité et la compatibilité avec les procédés de fabrication existants 1-5. Des structures telles que le poumon aviaire fournissent une source d&#39;inspiration. Comment pouvons-nous fabriquer des structures de cette complexité pour améliorer le transport de masse? La vaporisation d&#39;un composant sacrificiel (VASC) peut produire des structures microvasculaires de grande envergure, complexes 6-7. Cette méthode utilise la dépolymérisation thermique par évaporation et l&#39;élimination de poly (lactique), des fibres d&#39;acide pour former des canaux creux qui sont l&#39;inverse de la matrice de fibres. Il s&#39;agit d&#39;une technique de sacrifice compatible avec la fabrication existanteméthodes. Mètres de long, les modèles de microcanaux cylindriques peuvent être formées en utilisant ce procédé de fabrication. Ceci peut être utilisé pour créer des dispositifs vascularisés tels que les polymères auto-guérison et d&#39;unités de capture du carbone microvasculaires 3D 7-10. Les unités de capture du carbone ont été inspirés par le poumon aviaire qui fournit un moyen efficace d&#39;échange de gaz à rapport poids en raison de son utilisation en vol. Le parabronchus est composé de microcanaux hexagonale à motifs, qui fournit des taux de change élevé de l&#39;essence et des unités d&#39;échange de gaz structurellement stables. Afin de créer des unités d&#39;échange avec des caractéristiques micrométriques alignés en trois dimensions, nous avons développé une méthode de mise en tension indépendamment fibres en utilisant une planche de tension conçu sur mesure avec tuners de guitare et de plaques au laser micro-usinés. Chaque fibre est maintenue en place par la tension externe et le motif est défini par l&#39;emplacement des trous de la plaque à travers laquelle les fibres s&#39;exécutent.

<table border="1">
	<tbody>
		<tr>
			<td></td>
			<td></td>
			<td></td>
			<td>Reagent</td>
		</tr>
		<tr>
			<td>Tin (II) oxalate</td>
			<td>Sigma-Aldrich</td>
			<td>402761</td>
			<td></td>
		</tr>
		<tr>
			<td>Disperbyk 130</td>
			<td>BYK Additives &#38; Instruments</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Trifluoroethanol</td>
			<td>Halocarbon</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Malachite Green (technical grade)</td>
			<td>Sigma-Aldrich</td>
			<td>M6880</td>
			<td></td>
		</tr>
		<tr>
			<td>Sodium hydroxide (&#8805;98%, pellets)</td>
			<td>Sigma-Aldrich</td>
			<td>S5881</td>
			<td></td>
		</tr>
		<tr>
			<td>Polydimethylsiloxane (PDMS)</td>
			<td>Dow Corning</td>
			<td>3097358-1004</td>
			<td>Distributed from Ellsworth Adhesives</td>
		</tr>
		<tr>
			<td>Poly(lactic) acid fibers</td>
			<td>Teijin Monofilament</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td></td>
			<td></td>
			<td></td>
			<td>Material</td>
		</tr>
		<tr>
			<td>RW 20 Digital Mixer</td>
			<td>IKA</td>
			<td>3593001</td>
			<td></td>
		</tr>
		<tr>
			<td>Desiccator Jar</td>
			<td>Pyrex</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Vacuum Oven</td>
			<td>Fisher Scientific</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Third Hand</td>
			<td>Jameco Electronics</td>
			<td>26690</td>
			<td>Plate holder</td>
		</tr>
		<tr>
			<td>Glue Gun</td>
			<td>Stanley</td>
			<td>GR20L</td>
			<td></td>
		</tr>
		<tr>
			<td>PLA Spindle</td>
			<td></td>
			<td></td>
			<td>Custom made</td>
		</tr>
		<tr>
			<td>Tensioning Board</td>
			<td></td>
			<td></td>
			<td>Custom made</td>
		</tr>
	</tbody>
</table>

process of making three-dimensional microstructures using vaporization of a sacrificial component

Structures vasculaires dans les systèmes naturels sont en mesure d&#39;assurer le transport de masse élevée à travers des zones de surface élevée et une structure optimisée. Peu de techniques de fabrication de matière synthétique sont capables d&#39;imiter la complexité de ces structures tout en conservant l&#39;évolutivité. La vaporisation d&#39;un processus de composant sacrificiel (VASC) est en mesure de le faire. Ce processus utilise des fibres sacrificielles comme modèle pour former creux, microcanaux cylindriques incorporées dans une matrice. Tin (II) oxalate (SnOx) est incorporé dans le poly (lactique) fibres acide (PLA) qui facilite l&#39;utilisation de ce processus. Le SnOx catalyse la dépolymérisation des fibres PLA à des températures plus basses. Les monomères d&#39;acide lactique sont gazeux à ces températures, et peuvent être retirées de la matrice incorporé à des températures qui ne nuisent pas à la matrice. Ici, nous montrons une méthode pour aligner ces fibres à l&#39;aide de plaques de micro-usinés et un dispositif de tension pour créer des motifs complexes en trois dimensions des microcanaux disposés.Le processus permet l&#39;exploration de pratiquement n&#39;importe quel arrangement de fibres topologies et structures.

Cette procédure concerne un procédé de fabrication de structures microvasculaires incorporées dans une résine. Ces structures peuvent se conformer à une variété de modèles (Figure 2). La structure du réseau microvasculaire est seulement limité par les structures qui peuvent être formés avec les fibres sacrificielles. Utilisation d&#39;un agencement parallèle de canaux microvasculaires, le transport du gaz entre les courants de fluide est facilitée que les gaz ...

Watch this Scientific Journal Video about Process of Making Three-dimensional Microstructures using Vaporization of a Sacrificial Component at JoVE.com

Process of Making Three-dimensional Microstructures using Vaporization of a Sacrificial Component

La vaporisation d&#39;un processus de composant sacrificiel (VASC) est utilisé pour fabriquer des structures microvasculaires. Cette procédure utilise des fibres d&#39;acide poly (lactique sacrificielles) pour former des microcanaux creuses avec un positionnement géométrique 3D précises fournies par des plaques de guidage laser micro-usinés.

Processus de fabrication de microstructures tridimensionnelles en utilisant la vaporisation d&#39;un composant sacrificiel

Vascular structures in natural systems are able to provide high mass transport through high surface areas and optimized structure. Few synthetic material ...

process-making-three-dimensional-microstructures-using-vaporization

Research

JoVE Journal

Engineering

9.0K vues.  University of California, Irvine.  La vaporisation d'un processus de composant sacrificiel (VASC) est utilisé pour fabriquer des structures microvasculaires. Cette procédure utilise des fibres d'acide poly (lactique sacrificielles) pour former des microcanaux creuses avec un positionnement géométrique 3D précises fournies par des plaques de guidage laser micro-usinés. 

Vidéo: Process of Making Three-dimensional Microstructures using Vaporization of a Sacrificial Component

Fabrication, Densification, and Replica Molding of 3D Carbon Nanotube Microstructures

The introduction of new materials and processes to microfabrication has, in large part, enabled many important advances in microsystems, lab-on-a-chip devices, and their applications. In particular, capabilities for cost-effective fabrication of polymer microstructures were transformed by the advent of soft lithography and other micromolding techniques 1, 2, and this led a revolution in applications of microfabrication to biomedical engineering and biology. Nevertheless, it remains challenging to fabricate microstructures with well-defined nanoscale surface textures, and to fabricate arbitrary 3D shapes at the micro-scale. Robustness of master molds and maintenance of shape integrity is especially important to achieve high fidelity replication of complex structures and preserving their nanoscale surface texture. The combination of hierarchical textures, and heterogeneous shapes, is a profound challenge to existing microfabrication methods that largely rely upon top-down etching using fixed mask templates. On the other hand, the bottom-up synthesis of nanostructures such as nanotubes and nanowires can offer new capabilities to microfabrication, in particular by taking advantage of the collective self-organization of nanostructures, and local control of their growth behavior with respect to microfabricated patterns. 
Our goal is to introduce vertically aligned carbon nanotubes (CNTs), which we refer to as CNT "forests", as a new microfabrication material. We present details of a suite of related methods recently developed by our group: fabrication of CNT forest microstructures by thermal CVD from lithographically patterned catalyst thin films; self-directed elastocapillary densification of CNT microstructures; and replica molding of polymer microstructures using CNT composite master molds. In particular, our work shows that self-directed capillary densification ("capillary forming"), which is performed by condensation of a solvent onto the substrate with CNT microstructures, significantly increases the packing density of CNTs. This process enables directed transformation of vertical CNT microstructures into straight, inclined, and twisted shapes, which have robust mechanical properties exceeding those of typical microfabrication polymers. This in turn enables formation of nanocomposite CNT master molds by capillary-driven infiltration of polymers. The replica structures exhibit the anisotropic nanoscale texture of the aligned CNTs, and can have walls with sub-micron thickness and aspect ratios exceeding 50:1. Integration of CNT microstructures in fabrication offers further opportunity to exploit the electrical and thermal properties of CNTs, and diverse capabilities for chemical and biochemical functionalization 3.

We present methods for fabrication of patterned microstructures of vertically aligned carbon nanotubes (CNTs), and their use as master molds for production of polymer microstructures with organized nanoscale surface texture. The CNT forests are densified by condensation of solvent onto the substrate, which significantly increases their packing density and enables self-directed formation of 3D shapes.

Moulage de fabrication, de densification, et une réplique de 3D Microstructures de nanotubes de carbone

The introduction of new materials and processes to microfabrication has, in large part, enabled many important advances in microsystems, lab-on-a-chip ...

Recherche

Ingénierie

Synthesis of Phase-shift Nanoemulsions with Narrow Size Distributions for Acoustic Droplet Vaporization and Bubble-enhanced Ultrasound-mediated Ablation

High-intensity focused ultrasound (HIFU) is used clinically to thermally ablate tumors. To enhance localized heating and improve thermal ablation in tumors, lipid-coated perfluorocarbon droplets have been developed which can be vaporized by HIFU. The vasculature in many tumors is abnormally leaky due to their rapid growth, and nanoparticles are able to penetrate the fenestrations and passively accumulate within tumors. Thus, controlling the size of the droplets can result in better accumulation within tumors. In this report, the preparation of stable droplets in a phase-shift nanoemulsion (PSNE) with a narrow size distribution is described. PSNE were synthesized by sonicating a lipid solution in the presence of liquid perfluorocarbon. A narrow size distribution was obtained by extruding the PSNE multiple times using filters with pore sizes of 100 or 200 nm. The size distribution was measured over a 7-day period using dynamic light scattering. Polyacrylamide hydrogels containing PSNE were prepared for in vitro experiments. PSNE droplets in the hydrogels were vaporized with ultrasound and the resulting bubbles enhanced localized heating. Vaporized PSNE enables more rapid heating and also reduces the ultrasound intensity needed for thermal ablation. Thus, PSNE is expected to enhance thermal ablation in tumors, potentially improving therapeutic outcomes of HIFU-mediated thermal ablation treatments.

Phase-shift nanoemulsions (PSNE) can be vaporized using high intensity focused ultrasound to enhance localized heating and improve thermal ablation in tumors. In this report, the preparation of stable PSNE with a narrow size distribution is described. Furthermore, the impact of vaporized PSNE on ultrasound-mediated ablation is demonstrated in tissue-mimicking phantoms.

Synthèse de la Phase-shift nanoémulsions à distributions de taille étroite de vaporisation des gouttelettes acoustique et bulles améliorée échographie médiée par ablation

High-intensity  focused ultrasound (HIFU) is used clinically to thermally ablate tumors. To  enhance localized heating and improve thermal ablation in ...

High-resolution, High-speed, Three-dimensional Video Imaging with Digital Fringe Projection Techniques

Digital fringe projection (DFP) techniques provide dense 3D measurements of dynamically changing surfaces.&#160;Like the human eyes and brain, DFP uses triangulation between matching points in two views of the same scene at different angles to compute depth.&#160;However, unlike a stereo-based method, DFP uses a digital video projector to replace one of the cameras1. The projector rapidly projects a known sinusoidal pattern onto the subject, and the surface of the subject distorts these patterns in the camera&#8217;s field of view. Three distorted patterns (fringe images) from the camera can be used to compute the depth using triangulation.
Unlike other 3D measurement methods, DFP techniques lead to systems that tend to be faster, lower in equipment cost, more flexible, and easier to develop.&#160;DFP systems can also achieve the same measurement resolution as the camera.&#160;For this reason, DFP and other digital structured light techniques have recently been the focus of intense research (as summarized in1-5). Taking advantage of DFP, the graphics processing unit, and optimized algorithms, we have developed a system capable of 30&#160;Hz 3D video data acquisition, reconstruction, and display for over 300,000 measurement points per frame6,7.&#160;Binary defocusing DFP methods can achieve even greater speeds8.
Diverse applications can benefit from DFP techniques. Our collaborators have used our systems for facial function analysis9, facial animation10, cardiac mechanics studies11, and fluid surface measurements, but many other potential applications exist.&#160;This video will teach the fundamentals of DFP techniques and illustrate the design and operation of a binary defocusing DFP system.

This video describes the fundamentals of digital fringe projection techniques, which provide dense 3D measurements of dynamically changing surfaces.&#160;It also demonstrates the design and operation of a high-speed binary defocusing system based on these techniques.

Digital fringe projection (DFP) techniques provide dense 3D measurements of dynamically changing surfaces.&#160;Like the human eyes and brain, DFP uses ...

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.

Développement d&#39;une installation expérimentale pour la mesure du coefficient de restitution sous vide Conditions

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

Fabrication Process of Silicone-based Dielectric Elastomer Actuators

This contribution demonstrates the fabrication process of dielectric elastomer transducers (DETs). DETs are stretchable capacitors consisting of an elastomeric dielectric membrane sandwiched between two compliant electrodes. The large actuation strains of these transducers when used as actuators (over 300% area strain) and their soft and compliant nature has been exploited for a wide range of applications, including electrically tunable optics, haptic feedback devices, wave-energy harvesting, deformable cell-culture devices, compliant grippers, and propulsion of a bio-inspired fish-like airship. In most cases, DETs are made with a commercial proprietary acrylic elastomer and with hand-applied electrodes of carbon powder or carbon grease. This combination leads to non-reproducible and slow actuators exhibiting viscoelastic creep and a short lifetime. We present here a complete process flow for the reproducible fabrication of DETs based on thin elastomeric silicone films, including casting of thin silicone membranes, membrane release and prestretching, patterning of robust compliant electrodes, assembly and testing. The membranes are cast on flexible polyethylene terephthalate (PET) substrates coated with a water-soluble sacrificial layer for ease of release. The electrodes consist of carbon black particles dispersed into a silicone matrix and patterned using a stamping technique, which leads to precisely-defined compliant electrodes that present a high adhesion to the dielectric membrane on which they are applied.

This manuscript shows the fabrication process for the manufacture of dielectric elastomer soft actuators based on silicone membranes. The three key stages of production are presented in detail: blade casting of thin silicone membranes; pad printing of compliant electrodes; and the assembly of all the components.

Processus de fabrication des élastomères diélectriques Actionneurs à base de silicone

This contribution demonstrates the fabrication process of dielectric elastomer transducers (DETs). DETs are stretchable capacitors consisting of an ...

Using Synchrotron Radiation Microtomography to Investigate Multi-scale Three-dimensional Microelectronic Packages

Synchrotron radiation micro-tomography (SR&#181;T) is a non-destructive three-dimensional (3D) imaging technique that offers high flux for fast data acquisition times with high spatial resolution. In the electronics industry there is serious interest in performing failure analysis on 3D microelectronic packages, many which contain multiple levels of high-density interconnections. Often in tomography there is a trade-off between image resolution and the volume of a sample that can be imaged. This inverse relationship limits the usefulness of conventional computed tomography (CT) systems since a microelectronic package is often large in cross sectional area 100-3,600 mm2, but has important features on the micron scale. The micro-tomography beamline at the Advanced Light Source (ALS), in Berkeley, CA USA, has a setup which is adaptable and can be tailored to a sample&#39;s properties, i.e., density, thickness, etc., with a maximum allowable cross-section of 36 x 36 mm. This setup also has the option of being either monochromatic in the energy range ~7-43 keV or operating with maximum flux in white light mode using a polychromatic beam. Presented here are details of the experimental steps taken to image an entire 16 x 16 mm system within a package, in order to obtain 3D images of the system with a spatial resolution of 8.7 &#181;m all within a scan time of less than 3 min. Also shown are results from packages scanned in different orientations and a sectioned package for higher resolution imaging. In contrast a conventional CT system would take hours to record data with potentially poorer resolution. Indeed, the ratio of field-of-view to throughput time is much higher when using the synchrotron radiation tomography setup. The description below of the experimental setup can be implemented and adapted for use with many other multi-materials.

For this study synchrotron radiation micro-tomography, a non-destructive three-dimensional imaging technique, is employed to investigate an entire microelectronic package with a cross-sectional area of 16 x 16 mm. Due to the synchrotron&#39;s high flux and brightness the sample was imaged in just 3 min&#160;with an 8.7 &#181;m spatial resolution.

Utilisation de rayonnement synchrotron Microtomographie d&#39;enquêter sur Multi-échelle Forfaits microélectroniques en trois dimensions

Synchrotron radiation micro-tomography (SR&#181;T) is a non-destructive three-dimensional (3D) imaging technique that offers high flux for fast data ...

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.

Trois dimensions Velocimetry de suivi des particules pour Turbulence Applications: Cas d&#39;un débit 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 ...

Challenges in Rheological Characterization of Highly Concentrated Suspensions &#8212; A Case Study for Screen-printing Silver Pastes

A comprehensive rheological characterization of highly concentrated suspensions or pastes is mandatory for a targeted product development meeting the manifold requirements during processing and application of such complex fluids. In this investigation, measuring protocols for a conclusive assessment of different process relevant rheological parameters have been evaluated. This includes the determination of yield stress, viscosity, wall slip velocity, structural recovery after large deformation and elongation at break as well as tensile force during filament stretching.
The importance of concomitant video recordings during parallel-plate rotational rheometry for a significant determination of rheological quantities is demonstrated. The deformation profile and flow field at the sample edge can be determined using appropriate markers. Thus, measurement parameter settings and plate roughness values can be identified for which yield stress and viscosity measurements are possible. Slip velocity can be measured directly and measuring conditions at which plug flow, shear banding or sample spillover occur can be identified clearly. 
Video recordings further confirm that the change in shear moduli observed during three stage oscillatory shear tests with small deformation amplitude in stage I and III but large oscillation amplitude in stage II can be directly attributed to structural break down and recovery. For the pastes investigated here, the degree of irreversible, shear-induced structural change increases with increasing deformation amplitude in stage II until a saturation is reached at deformations corresponding to the crossover of G' and G'', but the irreversible damage is independent of the duration of large amplitude shear. 
A capillary breakup elongational rheometer and a tensile tester have been used to characterize deformation and breakup behavior of highly filled pastes in uniaxial elongation. Significant differences were observed in all experiments described above for two commercial screen-printing silver pastes used for front side metallization of Si-solar cells.

Challenges in Rheological Characterization of Highly Concentrated Suspensions &amp;#8212; A Case Study for Screen-printing Silver Pastes

A protocol for a robust and application relevant rheological characterization of highly concentrated suspensions is presented. Silver pastes used for screen-printing application in solar cell production are employed as model systems.

Défis à rhéologique Caractérisation des concentrés - Suspensions très Une étude de cas pour la sérigraphie argent Pastes

A comprehensive rheological characterization of highly concentrated suspensions or pastes is mandatory for a targeted product development meeting the ...

Predicting Catalyst Extrudate Breakage Based on the Modulus of Rupture

The mechanical strength of extruded catalysts and their natural or forced breakage by either collision against a surface or by a compressive load in a fixed bed are important phenomena in catalyst technology. The mechanical strength of the catalyst is measured here by its bending strength or flexural strength. This technique is relatively new from the perspective of applying it to commercial catalysts of typical sizes used in the industry. Catalyst breakage by collision against a surface is measured after a fall of the extrudates through the ambient air in a vertical pipe. Quantifying the impact force is done theoretically by applying Newton's second law. Measurement of catalyst breakage due to stress in a fixed bed is done following the standard procedure of the bulk crush strength test. Novel here is the focus on measuring the reduction in the length to diameter ratio of the extrudates as a function of the stress.

Here we present a protocol to measure the modulus of rupture of an extruded catalyst and the breakage of said catalyst extrudates by collision against a surface or by compression in a fixed bed.

Predicting catalyseur extrudat rupture basé sur le module de Rupture

The mechanical strength of extruded catalysts and their natural or forced breakage by either collision against a surface or by a compressive load in a ...

Three-Dimensional Ultrasonic Needle Tip Tracking with a Fiber-Optic Ultrasound Receiver

Ultrasound is frequently used for guiding minimally invasive procedures, but visualizing medical devices is often challenging with this imaging modality. When visualization is lost, the medical device can cause trauma to critical tissue structures. Here, a method to track the needle tip during ultrasound image-guided procedures is presented. This method involves the use of a fiber-optic ultrasound receiver that is affixed within the cannula of a medical needle to communicate ultrasonically with the external ultrasound probe. This custom probe comprises a central transducer element array and side element arrays. In addition to conventional two-dimensional (2D) B-mode ultrasound imaging provided by the central array, three-dimensional (3D) needle tip tracking is provided by the side arrays. For B-mode ultrasound imaging, a standard transmit-receive sequence with electronic beamforming is performed. For ultrasonic tracking, Golay-coded ultrasound transmissions from the 4 side arrays are received by the hydrophone sensor, and subsequently the received signals are decoded to identify the needle tip&#39;s spatial location with respect to the ultrasound imaging probe. As a preliminary validation of this method, insertions of the needle/hydrophone pair were performed in clinically realistic contexts. This novel ultrasound imaging/tracking method is compatible with current clinical workflow, and it provides reliable device tracking during in-plane and out-of-plane needle insertions.

Accurate and efficient visualization of invasive medical devices is extremely important in many ultrasound-guided minimally invasive procedures. Here, a method for localizing the spatial position of a needle tip relative to the ultrasound imaging probe is presented.

Aiguille à ultrasons tridimensionnel Tip suivi avec un récepteur à ultrasons de la fibre optique

Ultrasound is frequently used for guiding minimally invasive procedures, but visualizing medical devices is often challenging with this imaging modality. ...