Diese Arbeit wurde von der AFOSR Young Investigator Programm unter FA9550-12-1 bis 0352 und einem 3M Non-Tenured Faculty Award unterstützt. Die Autoren möchten Lalisa Stutts und Janine Tom für hilfreiche Diskussionen zu diesem Projekt danken. Die Autoren danken der Calit2 Microscopy Center und der Laserspektroskopie Einrichtung an der Universität von Kalifornien, Irvine zum Zulassen der Verwendung seiner Anlagen. Hodge Harland und die UCI Physical Sciences Machine Shop werden für die Herstellung von Werkzeugen anerkannt. Poly (Milchsäure) Säure Fasern wurden großzügig von Teijin Monofilament vorgesehen.

1. Catalyzing Opferfasern <ol><li> Wickeln der gewünschten Menge an Poly (Milchsäure) säure Fasern um den unteren ¾ kundenspezifischer Spindel. Reduzieren Faser Überlappung, um die maximale Fläche Belichtung liefern. </li><li> Mix deionisiertes H 2 O mit 40 ml Disperbyk 130 in einer geschlossenen Flasche und schütteln, bis eine homogene Lösung erhalten wird. Dann legen Sie eine 1.000 ml Becherglas in einem Wasserbad bei 37 ° C und gießen Trifluoräthanol in das Becherglas. Die Menge an H 2 O und TFE zu verwenden, hängt von der PLA Faserdurchmesser verwendet. <table border="1"><tbody><tr><td> Faserdurchmesser </td><td> Anzahl der H 2 O (ml) </td><td> Anzahl der 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> Hinzufügendie H 2 O / Disperbyk 187 Lösung in das Becherglas und rühren, bis es gleichmäßig. </li><li> 1 g Malachitgrün auf die Mischung und rühren bis gelöst. </li><li> Legen Sie die benutzerdefinierte Spindel mit Fasern in das Becherglas ½ Zoll vom Boden und befestigen Sie die Spindel mit einem digitalen Mischpult. Dann starten Sie den Digital-Mixer bei 400 Umdrehungen pro Minute. </li><li> Langsam 1,3 g Zinn (II)-oxalat (SnO x)-Katalysator zu der Mischung. Die Zugabe von SnOx muss, um große Ansammlungen von Material vor einem Absturz aus der Lösung zu verhindern schrittweise. </li><li> Der pH-Wert in der Mischung mit NaOH bis pH ~ 6,8-7,2. </li><li> Sichern Sie sich einen Deckel in den Becher und erhöhen die Spindel bis 500 UpM für 24 Stunden. Wenn eine Agglomeration von SnOx beobachtet wird, manuell brechen sie innerhalb der ersten 2 Stunden. </li><li> Entfernen Spindel und trocken im Ofen bei 35 ° C über Nacht. </li><li> Packen und entfernen Sie überschüssiges Katalysators aus den katalysierten PLA-Fasern. </li></ol> 2. Microvascular Gas Exchange Einheit Fabrication <ol><li> Besorgen Sie sich ein Paar von Laser-Cut Messing Strukturierung Messingplatten mit dem gewünschten Muster mikrovaskulären und bringt die Platten auf Cliphalterungen. </li><li> Schneiden Sie ein 10-Zoll-Länge von katalysierten Ballaststoffe pro Mikrokanalstruktur und entfernen Sie alle verbleibenden Katalysator Verwendung einer dickeren Platte geschnitten zum Faserdurchmesser (Zugplatte). </li><li> Taper die Kanten der Fasern mit der Spitze einer Heißklebepistole langsam extrudieren Faserspitzen. </li><li> Führen Sie die Fasern durch passende Löcher in den Messing Strukturierung Plattenpaaren. </li><li> Schrauben Sie die Platten auf einen Formkasten. Stellen Sie sicher, dass die Fasern nicht verdreht, wenn die Befestigung der Platten. </li><li> String die Faserspitzen durch die Stimmwirbeln des benutzerdefinierten Spannen Bord. </li><li> Tension die PLA-Fasern bis straff. Seien Sie vorsichtig, nicht über-Spannung und reißen die Fasern. </li><li> Entfernen Sie das überschüssige Partikel von der Faser Muster mit Druckluft. </li><li> Mix Polydimethylsiloxan (PDMS)-Basis mit Härtungsmittel in einer 10:1, v: v-Verhältnis. </li&gt; <li> Degas die Mischung unter Vakuum in einem Exsikkator jar für 10 min. </li><li> Gießen Sie die PDMS Mischung in die Form ein. Nicht direkt übergießen die Fasern um das Einfangen von Luftblasen zu reduzieren. </li><li> Mit einer 26 G Nadel, entfernen Sie alle Blasen innerhalb der Formkasten oder zwischen den Fasern. </li><li> Cure die PDMS-Gemisch bei 85 ° C für 30 min. </li><li> Lösen Sie die Messingplatten aus dem Formkasten, was sicher nicht die Platten biegen oder ziehen zu hart. Entfernen Sie die geheilt 1. Stufe aus dem Formkasten. </li><li> Führen Sie die Fasern durch eine RTV Endkappe durch Punktion Löcher in der Stirnwand mit einer Injektionsnadel. Abhängig vom Faserdurchmesser, mit einem Nadelabstand, die mindestens 2 x den Innendurchmesser dem Außendurchmesser des Faser. Pflegen Sie ein ähnliches Muster wie die Strukturierung Messing Platte, sondern darüber hinaus ausbreiten. </li><li> Befestigen Sie die Endkappen an den Enden eines größeren Formkasten und gießen Sie ein 2. Stufe der PDMS. </li><li> Entfernen Sie alle verbleibenden Gasblasen undhärten bei 85 ° C für 30 min. </li><li> Schneiden Sie überschüssige PLA-Fasern aus der Probe und in einem Vakuumofen bei 210 ° C für 24 Stunden oder bis die PLA-Fasern wurden meist evakuiert. </li><li> Wenn eine PLA nicht entfernt werden kann, leicht herauslösen der Mikrokanäle mit einer Injektion von 1 ml Chloroform. </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>

Wir haben für eine vorläufige Patent auf diese Technologie und US-Patent US Provisional Application Serien Nr. 61/590, 086 eingereicht.

Die Einführung des Katalysators in den SnOx PLA-Fasern können die Fasern bei einer niedrigeren Temperatur depolymerisieren. Hierdurch wird der Abbau der Einbettung Harz, in diesem Fall PDMS. Eine benutzerdefinierte Spindel wird benötigt, um richtig mischen die Behandlung Lösung (5A). Die Spindel wird von sechs Tragstäbe um einen zentralen Kern, der mit einem digitalen Mischpult legt zusammen. Die Fasern sind um die Tragstangen, so daß die Oberfläche der Umhüllung Fasern in Kontakt mit der kataly...

Natürliche Systeme verwenden umfangreichen Gefäßnetze viele biologische Funktionen zu erleichtern. Der Stofftransport kann effizient in solchen Systemen durch hohen Oberflächen-zu-Volumen-Verhältnisse und optimierte Verpackung Strukturen erreicht werden. Während viele synthetische Herstellungstechniken mikrovaskulären Strukturen erzeugen kann, kann keiner produzieren großen Mikrovaskulatur während Komplexität und Kompatibilität mit bestehenden Herstellungsverfahren 1-5. Bauwerke wie die Vogellunge bieten eine Inspiration. Wie können wir fabrizieren Strukturen dieser Komplexität für die Verbesserung Stofftransport? Die Verdampfung eines Sacrificial Komponente (Vasc) produzieren können große, komplexe Strukturen microvascular 6-7. Bei diesem Verfahren wird die thermische Depolymerisation und Abdampfen von Poly (milchsäure)-säure Fasern hohle Kanäle, die das Inverse der Faser Schablone zu bilden. Dies ist eine Opfer-Technik kompatibel mit bestehenden FertigungMethoden. Meter langen, zylindrischen Mikrokanalmuster können unter Verwendung dieses Herstellungsprozesses werden. Dies kann verwendet werden, um vascularized Geräte wie selbstheilende Polymere und 3D microvascular Carbon Capture Einheiten 7-10 schaffen. Die Carbon Capture Einheiten wurden von der aviären Lunge, die eine effiziente Gas-Austausch-Gewichts-Verhältnis bietet aufgrund seiner Verwendung im Flug inspiriert. Die parabronchus wird von hexagonal strukturierte Mikrokanäle, die hohen Gas-Wechselkursen und strukturell stabil Gasaustausch Einheiten bietet zusammen. Um den Austausch mit mikro-Einheiten bietet in drei Dimensionen ausgerichtet zu erstellen, entwickelten wir ein Verfahren zum Spannen unabhängig Fasern mit einem individuell gestalteten Spannung Board mit Guitar Tuner und Laser-Mikrobearbeitung Platten. Jede Faser wird durch externe Spannung gehalten wird und das Muster wird durch die Anordnung von Löchern in der Platte, durch welche die Fasern laufen soll.

<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

Vaskulären Strukturen in natürlichen Systemen sind in der Lage, hohe Massentransport durch große Oberfläche und optimierte Struktur bereitzustellen. Wenige Kunststoff Herstellungstechniken können, um die Komplexität dieser Strukturen nachzuahmen, während Skalierbarkeit. Die Verdampfung eines Sacrificial Komponente (Vasc) Prozess ist in der Lage, dies zu tun. Dieses Verfahren verwendet Opferfasern als Vorlage zu hohlen, zylindrischen Mikrokanäle in einer Matrix eingebettet sind. Zinn (II)-oxalat (SnO x) in Poly (Milchsäure) Säure (PLA) Fasern, die die Verwendung dieses Verfahrens erleichtert eingebettet. Die SnOx katalysiert die Depolymerisation des PLA-Fasern bei niedrigeren Temperaturen. Die Milchsäure-Monomeren gasförmig sind bei diesen Temperaturen und kann von der Matrix eingebettet, die bei Temperaturen nicht schaden der Matrix entfernt werden. Hier zeigen wir ein Verfahren zum Ausrichten dieser Fasern mit mikrobearbeiteten Platten und eine Spannvorrichtung komplexe Muster von dreidimensional angeordneten Mikrokanälen zu schaffen.Das Verfahren ermöglicht die Erforschung von praktisch jeder Anordnung von Faser-Topologien und Strukturen.

Dieses Verfahren stellt ein Verfahren zur Herstellung mikrovaskulären Strukturen in einem Harz eingebettet sind. Diese Strukturen können in einer Vielzahl von Mustern (Fig. 2) entsprechen. Die Struktur des mikrovaskulären Netzwerk nur durch die Strukturen, die mit den Opferfasern gebildet werden können, begrenzt. Ein paralleler Anordnung der mikrovaskulären Kanäle Gastransport zwischen Fluidströmen erleichtert als Gase durchlaufen eine durchlässige Membran zwischen d...

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

Die Verdampfung eines Sacrificial Komponente (Vasc)-Prozess wird verwendet, um mikrovaskulären Strukturen herzustellen. Bei diesem Verfahren wird Opfer Poly (Milchsäure) Säure Fasern hohl Mikrokanäle mit präzisen geometrischen 3D-Positionierung durch Laser-Mikrobearbeitung Leitbleche vorgesehen bilden.

Verfahren zur Herstellung von dreidimensionalen Mikrostrukturen mit Verdampfung eines Opferbauteil

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

8.9K Aufrufe.  University of California, Irvine.  Die Verdampfung eines Sacrificial Komponente (Vasc)-Prozess wird verwendet, um mikrovaskulären Strukturen herzustellen. Bei diesem Verfahren wird Opfer Poly (Milchsäure) Säure Fasern hohl Mikrokanäle mit präzisen geometrischen 3D-Positionierung durch Laser-Mikrobearbeitung Leitbleche vorgesehen bilden. 

Serie: 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.

Fabrication, Verdichtung, und Replica Molding von 3D-Carbon Nanotube Mikrostrukturen

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

Forschung

Ingenieurwesen

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.

Synthese von Phase-shift Nanoemulsionen mit enger Größenverteilung für Acoustic Droplet Vaporisation und Bubble-enhanced Ultraschall-vermittelte 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.

High-Auflösung, High-Speed-, Three-dimensional Imaging mit Digital-Video-Streifenprojektionstechnik

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.

Entwicklung eines Versuchsaufbau zur Messung des Restitutionskoeffizienten unter Vakuumbedingungen

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.

Herstellungsverfahren einer Silikonbasis Dielectric Elastomer Actuators

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.

Mit Synchrotronstrahlung Mikrotomographie Mehrskalige Dreidimensionale Mikroelektronische Bauteile zur Untersuchung

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.

Dreidimensionale Particle Tracking Velocimetry für Turbulence Anwendungen: Fall eines Jet Fluss

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.

Herausforderungen in rheologische Charakterisierung von hochkonzentrierten Suspensionen - Eine Fallstudie für Serigrafie Silberpasten

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.

Vorhersage Katalysator Extrudat Bruch basierend auf der e-Modul des Bruches

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.

Dreidimensionale Ultraschall Nadel Tipp Tracking mit einem Glasfaser-Ultraschall-Empfänger

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