Questo lavoro è stato supportato dal AFOSR Young Investigator programma sotto FA9550-12-1-0352 e 3M non di ruolo Facoltà Award. Gli autori desiderano ringraziare Lalisa Stutts e Janine Tom utile per la discussione relativa a questo progetto. Gli autori ringraziano il Centro di Microscopia Calit2 e Laser Spectroscopy strumento presso l&#39;Università della California, Irvine per consentire l&#39;utilizzo delle sue strutture. Hodge Harland e l&#39;UCI Physical Sciences Machine Shop sono riconosciuti per la fabbricazione di utensili. Poli (lattico) fibre di acido sono stati generosamente fornito da Teijin monofilamento.

1. Catalizzando Fibre sacrificali <ol><li> Avvolgere la quantità desiderata di poli (lattico) fibre di acido intorno al basso ¾ del mandrino personalizzato. Ridurre le sovrapposizioni della fibra per fornire la massima esposizione di superficie. </li><li> Mescolare deionizzata H 2 O con 40 ml di Disperbyk 130 in una bottiglia chiusa e agitare fino ad ottenere una soluzione omogenea. Quindi inserire un becher da 1000 ml in un bagno d&#39;acqua a 37 ° C e versare trifluoroethanol nel becher. La quantità di H 2 O e TFE per utilizzare dipende dal diametro delle fibre PLA utilizzato. <table border="1"><tbody><tr><td> Diametro fibra </td><td> Quantità di H 2 O (ml) </td><td> Importo di 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> Aggiungil&#39;H 2 O / 187 Disperbyk soluzione nel becher e mescolare fino uniforme. </li><li> Aggiungere 1 g di verde malachite al composto e mescolare fino a scioglimento. </li><li> Collocare il rullo personalizzato con fibre nel becher ½ pollice dal fondo e fissare il mandrino ad un mixer digitale. Quindi avviare il mixer digitale a 400 rpm. </li><li> Aggiungere lentamente 1,3 g di stagno (II) ossalato catalizzatore (snox) alla miscela. L&#39;aggiunta di snox deve essere graduale per evitare grandi agglomerati di materiale di schiantarsi dalla soluzione. </li><li> Regolare il pH nella miscela utilizzando NaOH fino a pH è ~ 6.8-7.2. </li><li> Fissare un coperchio nel becher e aumentare la rotazione del mandrino a 500 rpm per 24 hr. Se si osserva un agglomerato di snox, rompere manualmente entro le prime 2 ore. </li><li> Rimuovere mandrino e essiccare in stufa a 35 ° C per una notte. </li><li> Scartare e rimuovere l&#39;eccesso di catalizzatore dai catalizzate fibre PLA. </li></ol> 2. Microvascolare Gas Exchange Unità Fabrication <ol><li> Ottenere una coppia di ottone lastre di ottone di patterning tagliati al laser con il modello desiderato microvascolare e apporre le targhe sui titolari di clip. </li><li> Tagliare una lunghezza di 10 pollici di fibra catalizzata per microcanali e rimuovere qualsiasi catalizzatore rimanente utilizzando una piastra di spessore tagliato al diametro della fibra (trafila). </li><li> Cono i bordi delle fibre usando la punta di una pistola per colla a caldo per estrudere lentamente le punte della fibra. </li><li> Infilare le fibre attraverso i fori corrispondenti nelle coppie di piastre di patterning ottone. </li><li> Avvitare le piastre su una staffa. Assicurarsi che le fibre non siano attorcigliati durante il fissaggio delle piastre. </li><li> Stringa le punte fibra attraverso la messa a punto pioli del consiglio tensionamento personalizzato. </li><li> Tensione le fibre PLA fino teso. Fare attenzione a non sovra-tensione e far scattare le fibre. </li><li> Rimuovere particelle eccedenti dal modello in fibra con aria compressa. </li><li> Mix polidimetilsilossano (PDMS) base con il catalizzatore in un 10:1, v: v rapporto. </li&gt; <li> Degassare la miscela sotto vuoto in un barattolo essiccatore per 10 min. </li><li> Versare il composto PDMS nella casella di stampo. Non versare direttamente sopra le fibre per ridurre l&#39;intrappolamento di bolle d&#39;aria. </li><li> Utilizzando un ago G 26, rimuovere eventuali bolle all&#39;interno della staffa o tra le fibre. </li><li> Curare la miscela PDMS a 85 ° C per 30 min. </li><li> Allentare le tavole di bronzo dalla casella stampo, facendo attenzione a non piegare le piastre o tirare troppo duro. Rimuovere il curato 1 ° stadio dalla casella stampo. </li><li> Infilare le fibre attraverso un end-cap RTV perforando i fori nella testata con un ago ipodermico. Seconda della dimensione delle fibre, utilizzare un ago di calibro che ha almeno 2 volte il diametro interno del diametro esterno della fibra. Mantenere un modello simile come la piastra patterning di ottone, ma più ampiamente distribuiti. </li><li> Fissare le testate alle estremità di una casella di stampo più grande e versare un 2 ° stadio di PDMS. </li><li> Rimuovere eventuali bolle di gas rimanenti epolimerizzare a 85 ° C per 30 min. </li><li> Tagliare le fibre PLA eccesso dal campione e posto in un forno sotto vuoto a 210 ° C per 24 ore, o fino a quando le fibre di PLA sono stati per lo più evacuati. </li><li> Eventuale PLA non può essere rimosso, sciogliere delicatamente dalla microcanali utilizzando una iniezione di 1 ml di cloroformio. </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>

Abbiamo depositato un brevetto provvisorio su questa tecnologia und US Patent Application provvisoria US Serial No. 61/590, 086.

L&#39;introduzione del catalizzatore snox nelle fibre PLA permette alle fibre di depolimerizzano a una temperatura inferiore. Questo impedisce la degradazione della resina incorporamento, in questo caso PDMS. Un mandrino personalizzato è richiesto per miscelare correttamente la soluzione di trattamento (Figura 5A). Il mandrino è composta da sei aste di sostegno che circondano un nucleo centrale che si attacca ad un mixer digitale. Le fibre sono avvolte attorno alle aste di supporto in modo che l&#39;a...

I sistemi naturali utilizzano vaste reti vascolari per facilitare molte funzioni biologiche. Trasporto di massa può essere efficacemente conseguiti in tali sistemi ad elevata area superficiale di rapporti in volume e strutture di imballaggio ottimizzati. Mentre molte tecniche di fabbricazione sintetici possono produrre strutture microvascolari, nessuno può produrre microvasculature larga scala, mantenendo la complessità e la compatibilità con i metodi di produzione esistenti 1-5. Strutture come il polmone aviario forniscono una fonte di ispirazione. Come possiamo fabbricare strutture di questa complessità per migliorare il trasporto di massa? La vaporizzazione di un componente sacrificale (Vasc) può produrre strutture microvascolari di grandi dimensioni, complessi 6-7. Questo metodo utilizza la depolimerizzazione termica e per evaporazione rimozione di poli (lattico) fibre Acido per formare canali cave che sono l&#39;inverso del modello fibra. Questa è una tecnica sacrificale compatibile con la produzione esistentemetodi. Metro, cilindriche modelli microcanali possono essere formate con questo processo di fabbricazione. Questo può essere usato per creare dispositivi vascolarizzati come i polimeri di auto-guarigione e di unità di cattura del carbonio microvascolari 3D 7-10. Le unità di cattura del carbonio si sono ispirati al polmone aviario che fornisce un efficiente scambio gassoso-peso rapporto grazie al suo utilizzo in volo. Il parabronchus è composto di microcanali esagonale fantasia, che fornisce alti tassi di cambio di gas e unità di scambio di gas strutturalmente stabili. Al fine di creare le unità di scambio con caratteristiche microscala allineati in tre dimensioni, abbiamo sviluppato un metodo di tensionamento in modo indipendente fibre utilizzando una scheda di tensione progettato con sintonizzatori chitarra e piastre laser microlavorati. Ciascuna fibra è tenuto in posizione dalla tensione esterna e il pattern viene impostato dalla collocazione di fori nella piastra attraverso cui le fibre corrono.

<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

Strutture vascolari nei sistemi naturali sono in grado di fornire il trasporto ad alta massa attraverso le zone alte della superficie e della struttura ottimizzata. Poche tecniche di fabbricazione dei materiali sintetici sono in grado di imitare la complessità di queste strutture, mantenendo la scalabilità. La vaporizzazione di un processo componente sacrificale (Vasc) è in grado di farlo. Questo processo utilizza fibre sacrificali come modello per formare cavi, microcanali cilindrici incorporati all&#39;interno di una matrice. Stagno (II) ossalato (snox) è incorporato all&#39;interno di poli (lattico) acidi (PLA) fibre che facilita l&#39;uso di questo processo. Il snox catalizza la depolimerizzazione delle fibre PLA a temperature inferiori. I monomeri di acido lattico sono gassosi a queste temperature e possono essere rimossi dalla matrice incorporato a temperature che non danneggiano la matrice. Qui vi mostriamo un metodo per allineare queste fibre che utilizzano piastre microlavorati e un dispositivo di tensionamento per creare modelli complessi di tridimensionalmente microcanali schierati.Il processo permette l&#39;esplorazione di qualsiasi disposizione delle fibre di topologie e delle strutture.

Questa procedura fornisce un metodo di fabbricazione di strutture microvascolari incorporati all&#39;interno di una resina. Queste strutture possono conformarsi a una varietà di modelli (Figura 2). La struttura della rete microvascolare è limitata solo dalle strutture che si possono formare con le fibre sacrificali. Usando una disposizione parallela dei canali microvascolari, trasporto del gas tra flussi fluidi è facilitata come i gas attraversano una membrana inter-canal...

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 vaporizzazione di un processo Component sacrificale (Vasc) viene utilizzato per fabbricare strutture microvascolari. Questa procedura utilizza sacrificali poli (lattico) fibre di acido per formare microcanali cave con posizionamento geometrico 3D preciso fornito da piastre di guida microlavorati laser.

Processo di creazione di microstrutture tridimensionali mediante vaporizzazione di un componente sacrificale

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

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Research

JoVE Journal

Engineering

9.0K Views.  University of California, Irvine.  La vaporizzazione di un processo Component sacrificale (Vasc) viene utilizzato per fabbricare strutture microvascolari. Questa procedura utilizza sacrificali poli (lattico) fibre di acido per formare microcanali cave con posizionamento geometrico 3D preciso fornito da piastre di guida microlavorati laser. 

Video: 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.

Molding Fabrication, densificazione e Replica di microstrutture 3D Nanotubi di carbonio

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

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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.

Sintesi di fase-shift nanoemulsioni con distribuzioni di dimensioni strette per vaporizzazione Droplet acustico e Bubble-enhanced Ultrasound-mediata Ablazione

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.

Sviluppo di un apparato sperimentale per la misura del coefficiente di restituzione sotto vuoto Condizioni

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.

Fabbricazione Processo di base di silicone elastomero dielettrici Attuatori

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.

L&#39;utilizzo delle radiazioni al sincrotrone microtomografia a indagare multi-scala Pacchetti microelettronici tridimensionali

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.

Tridimensionale Velocimetry monitoraggio di particelle per applicazioni Turbulence: caso di flusso 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.

Le sfide in reologico Caratterizzazione di sospensioni altamente concentrato - un caso di studio per la serigrafia paste d&#39;argento

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.

Predizione catalizzatore estruso rottura basato sul modulo di rottura

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.

Tracking con un ricevitore di ultrasuono in fibra ottica a punta d'ago ad ultrasuoni tridimensionale

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