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Sample records for 3-d microstructures fabricated

  1. Fabrication of Conductive 3D Gold-Containing Microstructures via Direct Laser Writing.

    PubMed

    Blasco, Eva; Müller, Jonathan; Müller, Patrick; Trouillet, Vanessa; Schön, Markus; Scherer, Torsten; Barner-Kowollik, Christopher; Wegener, Martin

    2016-05-01

    3D conductive microstructures containing gold are fabricated by simultaneous photopolymerization and photoreduction via direct laser writing. The photoresist employed consists of water-soluble polymers and a gold precursor. The fabricated microstructures show good conductivity and are successfully employed for 3D connections between gold pads. PMID:26953811

  2. Fabrication of 3D metal/polymer microstructures by site-selective metal coating

    NASA Astrophysics Data System (ADS)

    Takeyasu, N.; Tanaka, T.; Kawata, S.

    2008-02-01

    Three-dimensional silver/polymer conjugated microstructures were fabricated by site-selective metal deposition on photopolymer structures in the sub-micrometer scale. Photopolymerizable resins with and without an amide group were independently prepared, and a three-dimensional polymer structure was fabricated with those resins by means of the two-photon-induced photopolymerization technique to confine the photopolymerization to a sub-micrometer volume. Silver was selectively deposited on the surface of the amide-containing polymer parts by electroless plating. This method can provide 3D arbitrary silver/polymer composite microstructures with sub-micrometer resolution.

  3. Fabrication, densification, and replica molding of 3D carbon nanotube microstructures.

    PubMed

    Copic, Davor; Park, Sei Jin; Tawfick, Sameh; De Volder, Michael; Hart, A John

    2012-01-01

    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

  4. EFAB: low-cost automated electrochemical batch fabrication of arbitrary 3D microstructures

    NASA Astrophysics Data System (ADS)

    Cohen, Adam L.; Frodis, Uri; Tseng, Fan-Gang; Zhang, Gang; Mansfeld, Florian; Will, Peter M.

    1999-08-01

    EFAB is a new micromachining process promising to rapidly and automatically batch fabricate high-aspect-ratio microstructures with arbitrary 3D geometry using inexpensive equipment. Conventional microfabrication processes have so far produced fairly simple geometries, yet many MEMS could benefit if more sophisticated shapes could be manufactured. By using 'Instant Masking' (IM) - a novel in-situ micropatterning method - to simplify, accelerate, and automate through-mask electroplating, EFAB can produce extremely complex shapes by depositing hundreds-thousands of layers at high speed. While other processes of the do not allow integration with ICs, EFAB operates at less than 60 degrees C, making IC compatibility a possibility. Alternative processes require costly facilities and equipment; EFAB separates photolithography from device fabrication, requiring a cleanroom only for mask-making, then depositing all layers in a low-cost, self-contained machine. All IM required can be prepared simultaneously, without repeating the lithography on each layer. Selective electrodeposition requires simply mating the mask with the substrate and applying current; in this way we have patterned well-defined features as small as 20 X 20 micrometers . The procedures in EFAB are selective electrodeposition, blanket electrodeposition, and planarization. To date we have built metal structures with up to 12 layers consisting of independently-moving components.

  5. Effects of microstructure on the fatigue crack propagation resistance in composite microstructure by 3D fabric modeling for energy transport

    SciTech Connect

    Ishihara, T.; Kim, J.K.; Kobayashi, Y.

    1995-10-01

    In this study, martensite-ferrite dual phase steel composed of martensite in hard phase and ferrite in soft phase is made 3 dimensions fabric composite for energy transport and the difference in fatigue crack propagation behavior resulting from the structural size is investigated by fracture mechanics and microstructural method. The main results obtained are as follows: (1) the fatigue crack propagation rate is influenced by the ferrite grain size, in other words, in the low {Delta}K region the fatigue crack propagation rate is decreased with decreasing of the grain size but the difference of propagation rate resulted from the structural size is decreased as {Delta}K is increased; (2) the above results are explained by the degree of crack arrest effect of the martensite phase for the fatigue crack propagation depending on the ratio of reversed plastic zone size to the ferrite grain size.

  6. 3D MEMS in Standard Processes: Fabrication, Quality Assurance, and Novel Measurement Microstructures

    NASA Technical Reports Server (NTRS)

    Lin, Gisela; Lawton, Russell A.

    2000-01-01

    Three-dimensional MEMS microsystems that are commercially fabricated require minimal post-processing and are easily integrated with CMOS signal processing electronics. Measurements to evaluate the fabrication process (such as cross-sectional imaging and device performance characterization) provide much needed feedback in terms of reliability and quality assurance. MEMS technology is bringing a new class of microscale measurements to fruition. The relatively small size of MEMS microsystems offers the potential for higher fidelity recordings compared to macrosize counterparts, as illustrated in the measurement of muscle cell forces.

  7. Image-based analysis of the internal microstructure of bone replacement scaffolds fabricated by 3D printing

    NASA Astrophysics Data System (ADS)

    Irsen, Stephan H.; Leukers, Barbara; Bruckschen, Björn; Tille, Carsten; Seitz, Hermann; Beckmann, Felix; Müller, Bert

    2006-08-01

    Rapid Prototyping and especially the 3D printing, allows generating complex porous ceramic scaffolds directly from powders. Furthermore, these technologies allow manufacturing patient-specific implants of centimeter size with an internal pore network to mimic bony structures including vascularization. Besides the biocompatibility properties of the base material, a high degree of open, interconnected porosity is crucial for the success of the synthetic bone graft. Pores with diameters between 100 and 500 μm are the prerequisite for vascularization to supply the cells with nutrients and oxygen, because simple diffusion transport is ineffective. The quantification of porosity on the macro-, micro-, and nanometer scale using well-established techniques such as Hg-porosimetry and electron microscopy is restricted. Alternatively, we have applied synchrotron-radiation-based micro computed tomography (SRμCT) to determine the porosity with high precision and to validate the macroscopic internal structure of the scaffold. We report on the difficulties in intensity-based segmentation for nanoporous materials but we also elucidate the power of SRμCT in the quantitative analysis of the pores at the different length scales.

  8. Fabrication of 3D Silicon Sensors

    SciTech Connect

    Kok, A.; Hansen, T.E.; Hansen, T.A.; Lietaer, N.; Summanwar, A.; Kenney, C.; Hasi, J.; Da Via, C.; Parker, S.I.; /Hawaii U.

    2012-06-06

    Silicon sensors with a three-dimensional (3-D) architecture, in which the n and p electrodes penetrate through the entire substrate, have many advantages over planar silicon sensors including radiation hardness, fast time response, active edge and dual readout capabilities. The fabrication of 3D sensors is however rather complex. In recent years, there have been worldwide activities on 3D fabrication. SINTEF in collaboration with Stanford Nanofabrication Facility have successfully fabricated the original (single sided double column type) 3D detectors in two prototype runs and the third run is now on-going. This paper reports the status of this fabrication work and the resulted yield. The work of other groups such as the development of double sided 3D detectors is also briefly reported.

  9. 3D Stretchable Arch Ribbon Array Fabricated via Grayscale Lithography

    PubMed Central

    Pang, Yu; Shu, Yi; Shavezipur, Mohammad; Wang, Xuefeng; Mohammad, Mohammad Ali; Yang, Yi; Zhao, Haiming; Deng, Ningqin; Maboudian, Roya; Ren, Tian-Ling

    2016-01-01

    Microstructures with flexible and stretchable properties display tremendous potential applications including integrated systems, wearable devices and bio-sensor electronics. Hence, it is essential to develop an effective method for fabricating curvilinear and flexural microstructures. Despite significant advances in 2D stretchable inorganic structures, large scale fabrication of unique 3D microstructures at a low cost remains challenging. Here, we demonstrate that the 3D microstructures can be achieved by grayscale lithography to produce a curved photoresist (PR) template, where the PR acts as sacrificial layer to form wavelike arched structures. Using plasma-enhanced chemical vapor deposition (PECVD) process at low temperature, the curved PR topography can be transferred to the silicon dioxide layer. Subsequently, plasma etching can be used to fabricate the arched stripe arrays. The wavelike silicon dioxide arch microstructure exhibits Young modulus and fracture strength of 52 GPa and 300 MPa, respectively. The model of stress distribution inside the microstructure was also established, which compares well with the experimental results. This approach of fabricating a wavelike arch structure may become a promising route to produce a variety of stretchable sensors, actuators and circuits, thus providing unique opportunities for emerging classes of robust 3D integrated systems. PMID:27345766

  10. 3D Stretchable Arch Ribbon Array Fabricated via Grayscale Lithography

    NASA Astrophysics Data System (ADS)

    Pang, Yu; Shu, Yi; Shavezipur, Mohammad; Wang, Xuefeng; Mohammad, Mohammad Ali; Yang, Yi; Zhao, Haiming; Deng, Ningqin; Maboudian, Roya; Ren, Tian-Ling

    2016-06-01

    Microstructures with flexible and stretchable properties display tremendous potential applications including integrated systems, wearable devices and bio-sensor electronics. Hence, it is essential to develop an effective method for fabricating curvilinear and flexural microstructures. Despite significant advances in 2D stretchable inorganic structures, large scale fabrication of unique 3D microstructures at a low cost remains challenging. Here, we demonstrate that the 3D microstructures can be achieved by grayscale lithography to produce a curved photoresist (PR) template, where the PR acts as sacrificial layer to form wavelike arched structures. Using plasma-enhanced chemical vapor deposition (PECVD) process at low temperature, the curved PR topography can be transferred to the silicon dioxide layer. Subsequently, plasma etching can be used to fabricate the arched stripe arrays. The wavelike silicon dioxide arch microstructure exhibits Young modulus and fracture strength of 52 GPa and 300 MPa, respectively. The model of stress distribution inside the microstructure was also established, which compares well with the experimental results. This approach of fabricating a wavelike arch structure may become a promising route to produce a variety of stretchable sensors, actuators and circuits, thus providing unique opportunities for emerging classes of robust 3D integrated systems.

  11. 3D Stretchable Arch Ribbon Array Fabricated via Grayscale Lithography.

    PubMed

    Pang, Yu; Shu, Yi; Shavezipur, Mohammad; Wang, Xuefeng; Mohammad, Mohammad Ali; Yang, Yi; Zhao, Haiming; Deng, Ningqin; Maboudian, Roya; Ren, Tian-Ling

    2016-01-01

    Microstructures with flexible and stretchable properties display tremendous potential applications including integrated systems, wearable devices and bio-sensor electronics. Hence, it is essential to develop an effective method for fabricating curvilinear and flexural microstructures. Despite significant advances in 2D stretchable inorganic structures, large scale fabrication of unique 3D microstructures at a low cost remains challenging. Here, we demonstrate that the 3D microstructures can be achieved by grayscale lithography to produce a curved photoresist (PR) template, where the PR acts as sacrificial layer to form wavelike arched structures. Using plasma-enhanced chemical vapor deposition (PECVD) process at low temperature, the curved PR topography can be transferred to the silicon dioxide layer. Subsequently, plasma etching can be used to fabricate the arched stripe arrays. The wavelike silicon dioxide arch microstructure exhibits Young modulus and fracture strength of 52 GPa and 300 MPa, respectively. The model of stress distribution inside the microstructure was also established, which compares well with the experimental results. This approach of fabricating a wavelike arch structure may become a promising route to produce a variety of stretchable sensors, actuators and circuits, thus providing unique opportunities for emerging classes of robust 3D integrated systems. PMID:27345766

  12. Fabricating 3D figurines with personalized faces.

    PubMed

    Tena, J Rafael; Mahler, Moshe; Beeler, Thabo; Grosse, Max; Hengchin Yeh; Matthews, Iain

    2013-01-01

    We present a semi-automated system for fabricating figurines with faces that are personalised to the individual likeness of the customer. The efficacy of the system has been demonstrated by commercial deployments at Walt Disney World Resort and Star Wars Celebration VI in Orlando Florida. Although the system is semi automated, human intervention is limited to a few simple tasks to maintain the high throughput and consistent quality required for commercial application. In contrast to existing systems that fabricate custom heads that are assembled to pre-fabricated plastic bodies, our system seamlessly integrates 3D facial data with a predefined figurine body into a unique and continuous object that is fabricated as a single piece. The combination of state-of-the-art 3D capture, modelling, and printing that are the core of our system provide the flexibility to fabricate figurines whose complexity is only limited by the creativity of the designer. PMID:24808129

  13. Direct single-layered fabrication of 3D concavo convex patterns in nano-stereolithography

    NASA Astrophysics Data System (ADS)

    Lim, T. W.; Park, S. H.; Yang, D. Y.; Kong, H. J.; Lee, K. S.

    2006-09-01

    A nano-surfacing process (NSP) is proposed to directly fabricate three-dimensional (3D) concavo convex-shaped microstructures such as micro-lens arrays using two-photon polymerization (TPP), a promising technique for fabricating arbitrary 3D highly functional micro-devices. In TPP, commonly utilized methods for fabricating complex 3D microstructures to date are based on a layer-by-layer accumulating technique employing two-dimensional sliced data derived from 3D computer-aided design data. As such, this approach requires much time and effort for precise fabrication. In this work, a novel single-layer exposure method is proposed in order to improve the fabricating efficiency for 3D concavo convex-shaped microstructures. In the NSP, 3D microstructures are divided into 13 sub-regions horizontally with consideration of the heights. Those sub-regions are then expressed as 13 characteristic colors, after which a multi-voxel matrix (MVM) is composed with the characteristic colors. Voxels with various heights and diameters are generated to construct 3D structures using a MVM scanning method. Some 3D concavo convex-shaped microstructures were fabricated to estimate the usefulness of the NSP, and the results show that it readily enables the fabrication of single-layered 3D microstructures.

  14. Hierarchical 3D microstructures from pyrolysis of epoxy resin

    NASA Astrophysics Data System (ADS)

    de Volder, Michael; Reynaerts, Dominiek; van Hoof, Chris; Hart, A. John

    2012-02-01

    Nature is replete with examples of microscale dendrites connected to tree-like backbones ranging from the overall structures of trees to vascular networks. These branched structures have emerged as a result of an optimization between the maximization of a surface area and the minimization of transport losses. Elucidating these sophisticated designs proposed by nature is of paramount importance for the creation of higher-efficiency materials. The fabrication of such structures is however particularly challenging at small scale. In this paper, we focus on amorphous carbon microstructures, which provide a wide electrochemical stability window, excellent bio-compatibility, and cost-effective fabrication. However, relatively few methods have been developed for the fabrication of hierarchical amorphous carbon microstructures.Here we show that novel anisotropic microarchitectures comprising vertically aligned amorphous carbon nanowires CNWs can be made by oxygen plasma treatment of epoxy resins, followed by pyrolysis. Interestingly, these structures can also be shaped into deterministic three-dimensional (3D) hierarchical structures where nanowires are anchored to a microsized solid carbon core. These structures could play a key role in the development of new electrodes for microsensors, bioprobes, batteries, and fuel cells.

  15. Experimental Diagenesis and 3D Printing of Evolving Carbonate Microstructures

    NASA Astrophysics Data System (ADS)

    Vanorio, T.

    2014-12-01

    Understanding how rock microstructures and, in turn, the spatial distribution of the properties of the rock skeleton (porosity, permeability, and elastic properties) evolve because of time-variant, thermo-chemo-mechanical processes is fundamental to decipher changes in the earth's crust due to rock-fluid interactions using remote geophysical monitoring methods. Laboratory experiments undoubtedly play a vital role in understanding the underlying basic rules that are needed to inform both simulations and modeling. Nevertheless, capturing coupled chemo-mechanical processes experimentally is a very challenging problem because as pore space deforms chemo-mechanically, the fluid reacts and flows through a deforming pore space. The result is that as much as we strive to achieve controlled conditions in laboratory experiments, it is extremely difficult to control for all of the possible responses of the highly heterogeneous pore network. To overcome such a limitation, we often resort to the fabrication of rock samples in the laboratory. Nevertheless, analogs are not rocks. This level of complexity requires an approach that advances beyond the limitations of each method, be it experimental or computational. I present an approach that takes advantage of the favorable aspects of experimental diagenesis, multi-scale imaging techniques (from pore scale to 3D rock volumes) and 3D printed models of varying carbonate microstructures. This approach allows us to study the evolution of natural pore network geometries from diagenesis experiments, use the basic rules of the evolving microstructures to drive the digital change of the pore network of the printed models in a well-controlled fashion as much possible in the analog experiments, and then iteratively measure the properties of the printed models at the scale of the laboratory. This integration can help make sense of the trackless evolution of properties in apparently scattered datasets such as those characterizing carbonate

  16. A simple method for producing freestanding 3D microstructures by integrated photomask micromolding

    NASA Astrophysics Data System (ADS)

    Li, Hui

    2015-12-01

    Freestanding three-dimensional (3D) microstructures are widely used in micro-electro-mechanical system (MEMS) applications or can function as microdevices themselves. However, microfabrication methods for freestanding 3D microstructures have limitations in shape, size, cost, and mass production, etc. In this work, integrated photomask micromolding is demonstrated, which uses a portable UV light source and chrome glass micromolding to fabricate 3D microstructures without alignment. Specifically, a chrome layer on one side of the glass micromold shields the excess filling SU-8 photoresist from UV exposure and only the SU-8 photoresist in mold cavities is crosslinked. The 3D microstructures produced using this method have very high dimensional accuracy and the profile error is approximately 1.5%. This method can be used with features of virtually any size and shape and can be integrated into highly-parallel micromolding processes and has potential for MEMS applications.

  17. Spray Coating of Photoresist for 3D Microstructures with Different Geometries

    NASA Astrophysics Data System (ADS)

    Yu, Liming; Yeow Lee, Yong; Tay, Francis E. H.; Iliescu, Ciprian

    2006-04-01

    This paper presents the advantages of spray coating technique as compared to the conventional spin coating method for photoresist coating of 3D microstructures. An optimized mix of photoresist AZ4620: MEK: PGMEA (1:1.5:0.5) was used to achieve good coverage and uniformity of photoresist not only on planar surface, but also along the trenches' sidewall. In order to achieve the ideal coverage of photoresist layer, the effects of the geometries of the microstructures were also considered. Then, we implement this technique for our application in a MEMS device to prove the viability and potentiality of spray coating of photoresist for fabrication of 3D microstructures.

  18. 3D thin film microstructures for space microrobots

    NASA Technical Reports Server (NTRS)

    Shimoyama, Isao

    1995-01-01

    Micromechanisms of locomotion and a manipulator with an external skeleton like the structure of an insect are proposed. Several micro-sized models were built on silicon wafers by using polysilicon for rigid plates and polyimide for elastic joints. Due to scale effects, friction in micromechanical components is dominant as compared to the inertial forces because friction is proportional to L(exp 2) while mass is proportional to L(exp 3). Therefore, to ensure efficient motion, rotational joint that exhibits rubbing should be avoided. In this paper, paper models of a robot leg and a micro-manipulator are presented to show structures with external skeletons and elastic joints. Then the large scale implementation using plastic plates, springs, and solenoids is demonstrated. Since the assembly technique is based on paper folding, it is compatible with thin film micro-fabrication and integrated circuit (IC) planar processes. Finally, several micromechanisms were fabricated on silicon wafers to demonstrate the feasibility of building a 3D microstructure from a single planar structure that can be used for space microrobots.

  19. Laser fabrication of 2D and 3D metal nanoparticle structures and arrays.

    PubMed

    Kuznetsov, A I; Kiyan, R; Chichkov, B N

    2010-09-27

    A novel method for fabrication of 2D and 3D metal nanoparticle structures and arrays is proposed. This technique is based on laser-induced transfer of molten metal nanodroplets from thin metal films. Metal nanoparticles are produced by solidification of these nanodroplets. The size of the transferred nanoparticles can be controllably changed in the range from 180 nm to 1500 nm. Several examples of complex 2D and 3D microstructures generated form gold nanoparticles are demonstrated. PMID:20941016

  20. Optofluidic fabrication for 3D-shaped particles.

    PubMed

    Paulsen, Kevin S; Di Carlo, Dino; Chung, Aram J

    2015-01-01

    Complex three-dimensional (3D)-shaped particles could play unique roles in biotechnology, structural mechanics and self-assembly. Current methods of fabricating 3D-shaped particles such as 3D printing, injection moulding or photolithography are limited because of low-resolution, low-throughput or complicated/expensive procedures. Here, we present a novel method called optofluidic fabrication for the generation of complex 3D-shaped polymer particles based on two coupled processes: inertial flow shaping and ultraviolet (UV) light polymerization. Pillars within fluidic platforms are used to deterministically deform photosensitive precursor fluid streams. The channels are then illuminated with patterned UV light to polymerize the photosensitive fluid, creating particles with multi-scale 3D geometries. The fundamental advantages of optofluidic fabrication include high-resolution, multi-scalability, dynamic tunability, simple operation and great potential for bulk fabrication with full automation. Through different combinations of pillar configurations, flow rates and UV light patterns, an infinite set of 3D-shaped particles is available, and a variety are demonstrated. PMID:25904062

  1. Optofluidic fabrication for 3D-shaped particles

    NASA Astrophysics Data System (ADS)

    Paulsen, Kevin S.; di Carlo, Dino; Chung, Aram J.

    2015-04-01

    Complex three-dimensional (3D)-shaped particles could play unique roles in biotechnology, structural mechanics and self-assembly. Current methods of fabricating 3D-shaped particles such as 3D printing, injection moulding or photolithography are limited because of low-resolution, low-throughput or complicated/expensive procedures. Here, we present a novel method called optofluidic fabrication for the generation of complex 3D-shaped polymer particles based on two coupled processes: inertial flow shaping and ultraviolet (UV) light polymerization. Pillars within fluidic platforms are used to deterministically deform photosensitive precursor fluid streams. The channels are then illuminated with patterned UV light to polymerize the photosensitive fluid, creating particles with multi-scale 3D geometries. The fundamental advantages of optofluidic fabrication include high-resolution, multi-scalability, dynamic tunability, simple operation and great potential for bulk fabrication with full automation. Through different combinations of pillar configurations, flow rates and UV light patterns, an infinite set of 3D-shaped particles is available, and a variety are demonstrated.

  2. 3D nanostructures fabricated by advanced stencil lithography.

    PubMed

    Yesilkoy, F; Flauraud, V; Rüegg, M; Kim, B J; Brugger, J

    2016-03-01

    This letter reports on a novel fabrication method for 3D metal nanostructures using high-throughput nanostencil lithography. Aperture clogging, which occurs on the stencil membranes during physical vapor deposition, is leveraged to create complex topographies on the nanoscale. The precision of the 3D nanofabrication method is studied in terms of geometric parameters and material types. The versatility of the technique is demonstrated by various symmetric and chiral patterns made of Al and Au. PMID:26884085

  3. 3D nanostructures fabricated by advanced stencil lithography

    NASA Astrophysics Data System (ADS)

    Yesilkoy, F.; Flauraud, V.; Rüegg, M.; Kim, B. J.; Brugger, J.

    2016-02-01

    This letter reports on a novel fabrication method for 3D metal nanostructures using high-throughput nanostencil lithography. Aperture clogging, which occurs on the stencil membranes during physical vapor deposition, is leveraged to create complex topographies on the nanoscale. The precision of the 3D nanofabrication method is studied in terms of geometric parameters and material types. The versatility of the technique is demonstrated by various symmetric and chiral patterns made of Al and Au.

  4. Metal nanoparticle direct inkjet printing for low-temperature 3D micro metal structure fabrication

    NASA Astrophysics Data System (ADS)

    Ko, Seung Hwan; Chung, Jaewon; Hotz, Nico; Nam, Koo Hyun; Grigoropoulos, Costas P.

    2010-12-01

    Inkjet printing of functional materials is a key technology toward ultra-low-cost, large-area electronics. We demonstrate low-temperature 3D micro metal structure fabrication by direct inkjet printing of metal nanoparticles (NPs) as a versatile, direct 3D metal structuring approach representing an alternative to conventional vacuum deposition and photolithographic methods. Metal NP ink was inkjet-printed to exploit the large melting temperature drop of the nanomaterial and the ease of the NP ink formulation. Parametric studies on the basic conditions for stable 3D inkjet printing of NP ink were carried out. Furthermore, diverse 3D metal microstructures, including micro metal pillar arrays, helices, zigzag and micro bridges were demonstrated and electrical characterization was performed. Since the process requires low temperature, it carries substantial potential for fabrication of electronics on a plastic substrate.

  5. Vertical Flow Lithography for Fabrication of 3D Anisotropic Particles.

    PubMed

    Habasaki, Shohei; Lee, Won Chul; Yoshida, Shotaro; Takeuchi, Shoji

    2015-12-22

    A microfluidics-based method for the 3D fabrication of anisotropic particles is reported. The method uses a vertical microchannel where tunable light patterns solidify photocurable resins for stacking multiple layers of the resins, thus enabling an application of stereolithography concepts to conventional flow lithography. Multilayered, tapered, and angular compartmental microparticles are demonstrated. PMID:26551590

  6. 3D printing of liquid metals as fugitive inks for fabrication of 3D microfluidic channels.

    PubMed

    Parekh, Dishit P; Ladd, Collin; Panich, Lazar; Moussa, Khalil; Dickey, Michael D

    2016-05-21

    This paper demonstrates a simple method to fabricate 3D microchannels and microvasculature at room temperature by direct-writing liquid metal as a sacrificial template. The formation of a surface oxide skin on the low-viscosity liquid metal stabilizes the shape of the printed metal for planar and out-of-plane structures. The printed structures can be embedded in a variety of soft (e.g. elastomeric) and rigid (e.g. thermoset) polymers. Both acid and electrochemical reduction are capable of removing the oxide skin that forms on the metal, which destabilizes the ink so that it withdraws from the encapsulating material due to capillary forces, resulting in nearly full recovery of the fugitive ink at room temperature. Whereas conventional fabrication procedures typically confine microchannels to 2D planes, the geometry of the printed microchannels can be varied from a simple 2D network to complex 3D architectures without using lithography. The method produces robust monolithic structures without the need for any bonding or assembling techniques that often limit the materials of construction of conventional microchannels. Removing select portions of the metal leaves behind 3D metal features that can be used as antennas, interconnects, or electrodes for interfacing with lab-on-a-chip devices. This paper describes the capabilities and limitations of this simple process. PMID:27025537

  7. 3D Printing Facilitated Scaffold-free Tissue Unit Fabrication

    PubMed Central

    Tan, Yu; Richards, Dylan J.; Trusk, Thomas C.; Visconti, Richard P.; Yost, Michael J.; Kindy, Mark S.; Drake, Christopher J.; Argraves, William Scott; Markwald, Roger R.; Mei, Ying

    2014-01-01

    Tissue spheroids hold great potential in tissue engineering as building blocks to assemble into functional tissues. To date, agarose molds have been extensively used to facilitate fusion process of tissue spheroids. As a molding material, agarose typically requires low temperature plates for gelation and/or heated dispenser units. Here, we proposed and developed an alginate-based, direct 3D mold-printing technology: 3D printing micro-droplets of alginate solution into biocompatible, bio-inert alginate hydrogel molds for the fabrication of scaffold-free tissue engineering constructs. Specifically, we developed a 3D printing technology to deposit micro-droplets of alginate solution on calcium containing substrates in a layer-by-layer fashion to prepare ring-shaped 3D hydrogel molds. Tissue spheroids composed of 50% endothelial cells and 50% smooth muscle cells were robotically placed into the 3D printed alginate molds using a 3D printer, and were found to rapidly fuse into toroid-shaped tissue units. Histological and immunofluorescence analysis indicated that the cells secreted collagen type I playing a critical role in promoting cell-cell adhesion, tissue formation and maturation. PMID:24717646

  8. 3D printing facilitated scaffold-free tissue unit fabrication.

    PubMed

    Tan, Yu; Richards, Dylan J; Trusk, Thomas C; Visconti, Richard P; Yost, Michael J; Kindy, Mark S; Drake, Christopher J; Argraves, William Scott; Markwald, Roger R; Mei, Ying

    2014-06-01

    Tissue spheroids hold great potential in tissue engineering as building blocks to assemble into functional tissues. To date, agarose molds have been extensively used to facilitate fusion process of tissue spheroids. As a molding material, agarose typically requires low temperature plates for gelation and/or heated dispenser units. Here, we proposed and developed an alginate-based, direct 3D mold-printing technology: 3D printing microdroplets of alginate solution into biocompatible, bio-inert alginate hydrogel molds for the fabrication of scaffold-free tissue engineering constructs. Specifically, we developed a 3D printing technology to deposit microdroplets of alginate solution on calcium containing substrates in a layer-by-layer fashion to prepare ring-shaped 3D hydrogel molds. Tissue spheroids composed of 50% endothelial cells and 50% smooth muscle cells were robotically placed into the 3D printed alginate molds using a 3D printer, and were found to rapidly fuse into toroid-shaped tissue units. Histological and immunofluorescence analysis indicated that the cells secreted collagen type I playing a critical role in promoting cell-cell adhesion, tissue formation and maturation. PMID:24717646

  9. Micro stereo lithography and fabrication of 3D microdevices

    NASA Astrophysics Data System (ADS)

    Varadan, Vijay K.; Varadan, Vasundara V.

    1999-08-01

    Micro Stereo Lithography (MSL) is a poor man's LIGA for fabricating high aspect ratio MEMS devices in UV curable semiconducting polymers using either two computer-controlled low inertia galvanometric mirrors with the aid of focusing lens or an array of optical fibers. For 3D MEMS devices, the polymers need to have conductive and possibly piezoelectric or ferroelectric properties. Such polymers are being developed at Penn State resulting in microdevices for fluid and drug delivery. Applications may include implanted medical delivery systems, chemical and biological instruments, fluid delivery in engines, pump coolants and refrigerants for local cooling of electronic components. With the invention of organic thin film transistor, now it is possible to fabricate 3D polymeric MEMS devices with built-in-electronics similar to silicon based microelectronics. In this paper, a brief introduction of MSL system is presented followed by a detailed design and development of micro pumps using this approach.

  10. A method to fabricate disconnected silver nanostructures in 3D.

    PubMed

    Vora, Kevin; Kang, SeungYeon; Mazur, Eric

    2012-01-01

    The standard nanofabrication toolkit includes techniques primarily aimed at creating 2D patterns in dielectric media. Creating metal patterns on a submicron scale requires a combination of nanofabrication tools and several material processing steps. For example, steps to create planar metal structures using ultraviolet photolithography and electron-beam lithography can include sample exposure, sample development, metal deposition, and metal liftoff. To create 3D metal structures, the sequence is repeated multiple times. The complexity and difficulty of stacking and aligning multiple layers limits practical implementations of 3D metal structuring using standard nanofabrication tools. Femtosecond-laser direct-writing has emerged as a pre-eminent technique for 3D nanofabrication.(1,2) Femtosecond lasers are frequently used to create 3D patterns in polymers and glasses.(3-7) However, 3D metal direct-writing remains a challenge. Here, we describe a method to fabricate silver nanostructures embedded inside a polymer matrix using a femtosecond laser centered at 800 nm. The method enables the fabrication of patterns not feasible using other techniques, such as 3D arrays of disconnected silver voxels.(8) Disconnected 3D metal patterns are useful for metamaterials where unit cells are not in contact with each other,(9) such as coupled metal dot(10,11)or coupled metal rod(12,13) resonators. Potential applications include negative index metamaterials, invisibility cloaks, and perfect lenses. In femtosecond-laser direct-writing, the laser wavelength is chosen such that photons are not linearly absorbed in the target medium. When the laser pulse duration is compressed to the femtosecond time scale and the radiation is tightly focused inside the target, the extremely high intensity induces nonlinear absorption. Multiple photons are absorbed simultaneously to cause electronic transitions that lead to material modification within the focused region. Using this approach, one can

  11. 3D ultrasound imaging for prosthesis fabrication and diagnostic imaging

    SciTech Connect

    Morimoto, A.K.; Bow, W.J.; Strong, D.S.

    1995-06-01

    The fabrication of a prosthetic socket for a below-the-knee amputee requires knowledge of the underlying bone structure in order to provide pressure relief for sensitive areas and support for load bearing areas. The goal is to enable the residual limb to bear pressure with greater ease and utility. Conventional methods of prosthesis fabrication are based on limited knowledge about the patient`s underlying bone structure. A 3D ultrasound imaging system was developed at Sandia National Laboratories. The imaging system provides information about the location of the bones in the residual limb along with the shape of the skin surface. Computer assisted design (CAD) software can use this data to design prosthetic sockets for amputees. Ultrasound was selected as the imaging modality. A computer model was developed to analyze the effect of the various scanning parameters and to assist in the design of the overall system. The 3D ultrasound imaging system combines off-the-shelf technology for image capturing, custom hardware, and control and image processing software to generate two types of image data -- volumetric and planar. Both volumetric and planar images reveal definition of skin and bone geometry with planar images providing details on muscle fascial planes, muscle/fat interfaces, and blood vessel definition. The 3D ultrasound imaging system was tested on 9 unilateral below-the- knee amputees. Image data was acquired from both the sound limb and the residual limb. The imaging system was operated in both volumetric and planar formats. An x-ray CT (Computed Tomography) scan was performed on each amputee for comparison. Results of the test indicate beneficial use of ultrasound to generate databases for fabrication of prostheses at a lower cost and with better initial fit as compared to manually fabricated prostheses.

  12. Solid organ fabrication: comparison of decellularization to 3D bioprinting.

    PubMed

    Jung, Jangwook P; Bhuiyan, Didarul B; Ogle, Brenda M

    2016-01-01

    Solid organ fabrication is an ultimate goal of Regenerative Medicine. Since the introduction of Tissue Engineering in 1993, functional biomaterials, stem cells, tunable microenvironments, and high-resolution imaging technologies have significantly advanced efforts to regenerate in vitro culture or tissue platforms. Relatively simple flat or tubular organs are already in (pre)clinical trials and a few commercial products are in market. The road to more complex, high demand, solid organs including heart, kidney and lung will require substantive technical advancement. Here, we consider two emerging technologies for solid organ fabrication. One is decellularization of cadaveric organs followed by repopulation with terminally differentiated or progenitor cells. The other is 3D bioprinting to deposit cell-laden bio-inks to attain complex tissue architecture. We reviewed the development and evolution of the two technologies and evaluated relative strengths needed to produce solid organs, with special emphasis on the heart and other tissues of the cardiovascular system. PMID:27583168

  13. Facile 3D Metal Electrode Fabrication for Energy Applications via Inkjet Printing and Shape Memory Polymer

    NASA Astrophysics Data System (ADS)

    Roberts, R. C.; Wu, J.; Hau, N. Y.; Chang, Y. H.; Feng, S. P.; Li, D. C.

    2014-11-01

    This paper reports on a simple 3D metal electrode fabrication technique via inkjet printing onto a thermally contracting shape memory polymer (SMP) substrate. Inkjet printing allows for the direct patterning of structures from metal nanoparticle bearing liquid inks. After deposition, these inks require thermal curing steps to render a stable conductive film. By printing onto a SMP substrate, the metal nanoparticle ink can be cured and substrate shrunk simultaneously to create 3D metal microstructures, forming a large surface area topology well suited for energy applications. Polystyrene SMP shrinkage was characterized in a laboratory oven from 150-240°C, resulting in a size reduction of 1.97-2.58. Silver nanoparticle ink was patterned into electrodes, shrunk, and the topology characterized using scanning electron microscopy. Zinc-Silver Oxide microbatteries were fabricated to demonstrate the 3D electrodes compared to planar references. Characterization was performed using 10M potassium hydroxide electrolyte solution doped with zinc oxide (57g/L). After a 300s oxidation at 3Vdc, the 3D electrode battery demonstrated a 125% increased capacity over the reference cell. Reference cells degraded with longer oxidations, but the 3D electrodes were fully oxidized for 4 hours, and exhibited a capacity of 5.5mA-hr/cm2 with stable metal performance.

  14. Development of the flow behavior model for 3D scaffold fabrication in the polymer deposition process by a heating method

    NASA Astrophysics Data System (ADS)

    Kim, Jong Young; Park, Jung Kyu; Hahn, Sei Kwang; Kwon, Tai Hun; Cho, Dong-Woo

    2009-10-01

    The flow behavior model for 3D scaffold fabrication in the polymer deposition process by the heating method was developed for enhanced efficiency of the deposition process. The analysis of the polymer flow property is very important in the fabrication process of precise micro-structures such as scaffolds. In this study, a deposition model considering fluid mechanics and heat transfer phenomena was built up and introduced for the estimation of the fluid behavior of molten polymer. The effectiveness of the simulation model was verified through comparison with the experimental result in the case of PCL biomaterial. In addition, the effects of various parameters, such as pressure, temperature and nozzle size, were predicted through simulation before experimental approaches. Through the fabrication of 3D scaffold, it is concluded that this model is useful in predicting the flow behavior characteristics in the micro-structure fabrication process, which is based on the heating method.

  15. Fabrication of computationally designed scaffolds by low temperature 3D printing.

    PubMed

    Castilho, Miguel; Dias, Marta; Gbureck, Uwe; Groll, Jürgen; Fernandes, Paulo; Pires, Inês; Gouveia, Barbara; Rodrigues, Jorge; Vorndran, Elke

    2013-09-01

    The development of artificial bone substitutes that mimic the properties of bone and simultaneously promote the desired tissue regeneration is a current issue in bone tissue engineering research. An approach to create scaffolds with such characteristics is based on the combination of novel design and additive manufacturing processes. The objective of this work is to characterize the microstructural and the mechanical properties of scaffolds developed by coupling both topology optimization and a low temperature 3D printing process. The scaffold design was obtained using a topology optimization approach to maximize the permeability with constraints on the mechanical properties. This procedure was studied to be suitable for the fabrication of a cage prototype for tibial tuberosity advancement application, which is one of the most recent and promising techniques to treat cruciate ligament rupture in dogs. The microstructural and mechanical properties of the scaffolds manufactured by reacting α/β-tricalcium phosphate with diluted phosphoric acid were then assessed experimentally and the scaffolds strength reliability was determined. The results demonstrate that the low temperature 3D printing process is a reliable option to create synthetic scaffolds with tailored properties, and when coupled with topology optimization design it can be a powerful tool for the fabrication of patient-specific bone implants. PMID:23887064

  16. Plasmon assisted 3D microstructuring of gold nanoparticle-doped polymers

    NASA Astrophysics Data System (ADS)

    Jonušauskas, Linas; Lau, Marcus; Gruber, Peter; Gökce, Bilal; Barcikowski, Stephan; Malinauskas, Mangirdas; Ovsianikov, Aleksandr

    2016-04-01

    3D laser lithography of a negative photopolymer (zirconium/silicon hybrid solgel SZ2080) doped with gold nanoparticles (Au NPs) is performed with a 515 nm and 300 fs laser system and the effect of doping is explored. By varying the laser-generated Au NP doping concentration from 4.8 · 10-6 wt% to 9.8 · 10-3 wt% we find that the fabricated line widths are enlarged by up to 14.8% compared to structures achieved in pure SZ2080. While implicating a positive effect on the photosensitivity, the doping has no adverse impact on the mechanical quality of intricate 3D microstructures produced from the doped nanocompound. Additionally, we found that SZ2080 increases the long term (˜months) colloidal stability of Au NPs in isopropanol. By discussing the nanoparticle-light interaction in the 3D polymer structures we provide implications that our findings might have on other fields, such as biomedicine and photonics.

  17. Plasmon assisted 3D microstructuring of gold nanoparticle-doped polymers.

    PubMed

    Jonušauskas, Linas; Lau, Marcus; Gruber, Peter; Gökce, Bilal; Barcikowski, Stephan; Malinauskas, Mangirdas; Ovsianikov, Aleksandr

    2016-04-15

    3D laser lithography of a negative photopolymer (zirconium/silicon hybrid solgel SZ2080) doped with gold nanoparticles (Au NPs) is performed with a 515 nm and 300 fs laser system and the effect of doping is explored. By varying the laser-generated Au NP doping concentration from 4.8 · 10(-6) wt% to 9.8 · 10(-3) wt% we find that the fabricated line widths are enlarged by up to 14.8% compared to structures achieved in pure SZ2080. While implicating a positive effect on the photosensitivity, the doping has no adverse impact on the mechanical quality of intricate 3D microstructures produced from the doped nanocompound. Additionally, we found that SZ2080 increases the long term (∼months) colloidal stability of Au NPs in isopropanol. By discussing the nanoparticle-light interaction in the 3D polymer structures we provide implications that our findings might have on other fields, such as biomedicine and photonics. PMID:26925538

  18. In vitro and in vivo biocompatibility study on laser 3D microstructurable polymers

    NASA Astrophysics Data System (ADS)

    Malinauskas, Mangirdas; Baltriukiene, Daiva; Kraniauskas, Antanas; Danilevicius, Paulius; Jarasiene, Rasa; Sirmenis, Raimondas; Zukauskas, Albertas; Balciunas, Evaldas; Purlys, Vytautas; Gadonas, Roaldas; Bukelskiene, Virginija; Sirvydis, Vytautas; Piskarskas, Algis

    2012-09-01

    Films and microstructured scaffolds have been fabricated using direct laser writing out of different polymers: hybrid organic-inorganic ORMOCORE b59, acrylate-based AKRE23, novel organic-inorganic Zr containing hybrid SZ2080, and biodegradable PEG-DA-258. Adult myogenic stem cells were grown on these surfaces in vitro. Their adhesion, growth, and viability test results suggest good potential applicability of the materials in biomedical practice. Pieces of these polymers were implanted in rat's paravertebral back tissue. Histological examination of the implants and surrounding tissue ex vivo after 3 weeks of implantation was conducted and results show the materials to be at least as biocompatible as surgical clips or sutures. The applied direct laser writing technique seems to offer good future prospects in a polymeric 3D scaffold design for artificial tissue engineering with autologous stem cells.

  19. Mechanism and Microstructure Transformation of 3D-Si/LG5 Composites by High Temperature Diffusion Treatment

    NASA Astrophysics Data System (ADS)

    Xiu, Ziyang; Deng, Zongquan; Wang, Xiaofeng; Wu, Gaohui

    A dense and uniform Sip/LG5 composite were fabricated by squeeze casting technology, and high temperature diffusion treatment was adapted to the composite. Microstructure observation indicated that Si transformed from irregular particles to 3D-structure. Fine dispersive precipitates Si were also observed on Si-Al interface and within Al matrix, smoothing and improving the interface. Based on the microstructure observation, three transformation stages were designated: melting, dissolution and precipitation, solidification. Thermodynamics and kinetics of the transformation can be explained by Gibbs-Thomson effect.

  20. 3D printing of novel osteochondral scaffolds with graded microstructure.

    PubMed

    Nowicki, Margaret A; Castro, Nathan J; Plesniak, Michael W; Zhang, Lijie Grace

    2016-10-14

    Osteochondral tissue has a complex graded structure where biological, physiological, and mechanical properties vary significantly over the full thickness spanning from the subchondral bone region beneath the joint surface to the hyaline cartilage region at the joint surface. This presents a significant challenge for tissue-engineered structures addressing osteochondral defects. Fused deposition modeling (FDM) 3D bioprinters present a unique solution to this problem. The objective of this study is to use FDM-based 3D bioprinting and nanocrystalline hydroxyapatite for improved bone marrow human mesenchymal stem cell (hMSC) adhesion, growth, and osteochondral differentiation. FDM printing parameters can be tuned through computer aided design and computer numerical control software to manipulate scaffold geometries in ways that are beneficial to mechanical performance without hindering cellular behavior. Additionally, the ability to fine-tune 3D printed scaffolds increases further through our investment casting procedure which facilitates the inclusion of nanoparticles with biochemical factors to further elicit desired hMSC differentiation. For this study, FDM was used to print investment-casting molds innovatively designed with varied pore distribution over the full thickness of the scaffold. The mechanical and biological impacts of the varied pore distributions were compared and evaluated to determine the benefits of this physical manipulation. The results indicate that both mechanical properties and cell performance improve in the graded pore structures when compared to homogeneously distributed porous and non-porous structures. Differentiation results indicated successful osteogenic and chondrogenic manipulation in engineered scaffolds. PMID:27606933

  1. 3D sensors and micro-fabricated detector systems

    NASA Astrophysics Data System (ADS)

    Da Vià, Cinzia

    2014-11-01

    Micro-systems based on the Micro Electro Mechanical Systems (MEMS) technology have been used in miniaturized low power and low mass smart structures in medicine, biology and space applications. Recently similar features found their way inside high energy physics with applications in vertex detectors for high-luminosity LHC Upgrades, with 3D sensors, 3D integration and efficient power management using silicon micro-channel cooling. This paper reports on the state of this development.

  2. Quantitative analysis and feature recognition in 3-D microstructural data sets

    NASA Astrophysics Data System (ADS)

    Lewis, A. C.; Suh, C.; Stukowski, M.; Geltmacher, A. B.; Spanos, G.; Rajan, K.

    2006-12-01

    A three-dimensional (3-D) reconstruction of an austenitic stainless-steel microstructure was used as input for an image-based finite-element model to simulate the anisotropic elastic mechanical response of the microstructure. The quantitative data-mining and data-warehousing techniques used to correlate regions of high stress with critical microstructural features are discussed. Initial analysis of elastic stresses near grain boundaries due to mechanical loading revealed low overall correlation with their location in the microstructure. However, the use of data-mining and feature-tracking techniques to identify high-stress outliers revealed that many of these high-stress points are generated near grain boundaries and grain edges (triple junctions). These techniques also allowed for the differentiation between high stresses due to boundary conditions of the finite volume reconstructed, and those due to 3-D microstructural features.

  3. Optical fabrication of lightweighted 3D printed mirrors

    NASA Astrophysics Data System (ADS)

    Herzog, Harrison; Segal, Jacob; Smith, Jeremy; Bates, Richard; Calis, Jacob; De La Torre, Alyssa; Kim, Dae Wook; Mici, Joni; Mireles, Jorge; Stubbs, David M.; Wicker, Ryan

    2015-09-01

    Direct Metal Laser Sintering (DMLS) and Electron Beam Melting (EBM) 3D printing technologies were utilized to create lightweight, optical grade mirrors out of AlSi10Mg aluminum and Ti6Al4V titanium alloys at the University of Arizona in Tucson. The mirror prototypes were polished to meet the λ/20 RMS and λ/4 P-V surface figure requirements. The intent of this project was to design topologically optimized mirrors that had a high specific stiffness and low surface displacement. Two models were designed using Altair Inspire software, and the mirrors had to endure the polishing process with the necessary stiffness to eliminate print-through. Mitigating porosity of the 3D printed mirror blanks was a challenge in the face of reconciling new printing technologies with traditional optical polishing methods. The prototypes underwent Hot Isostatic Press (HIP) and heat treatment to improve density, eliminate porosity, and relieve internal stresses. Metal 3D printing allows for nearly unlimited topological constraints on design and virtually eliminates the need for a machine shop when creating an optical quality mirror. This research can lead to an increase in mirror mounting support complexity in the manufacturing of lightweight mirrors and improve overall process efficiency. The project aspired to have many future applications of light weighted 3D printed mirrors, such as spaceflight. This paper covers the design/fab/polish/test of 3D printed mirrors, thermal/structural finite element analysis, and results.

  4. Combination of thermal extrusion printing and ultrafast laser fabrication for the manufacturing of 3D composite scaffolds

    NASA Astrophysics Data System (ADS)

    Balčiūnas, Evaldas; Lukoševičius, Laurynas; Mackevičiūtė, Dovilė; Rekštytė, Sima; Rutkūnas, Vygandas; Paipulas, Domas; Stankevičiūtė, Karolina; Baltriukienė, Daiva; Bukelskienė, Virginija; Piskarskas, Algis P.; Malinauskas, Mangirdas

    2014-03-01

    We present a novel approach to manufacturing 3D microstructured composite scaffolds for tissue engineering applications. A thermal extrusion 3D printer - a simple, low-cost tabletop device enabling rapid materialization of CAD models in plastics - was used to produce cm-scale microporous scaffolds out of polylactic acid (PLA). The fabricated objects were subsequently immersed in a photosensitive monomer solution and direct laser writing technique (DLW) was used to refine its inner structure by fabricating a fine mesh inside the previously produced scaffold. In addition, a composite material structure out of four different materials fabricated via DLW is presented. This technique, empowered by ultrafast lasers allows 3D structuring with high spatial resolution in a great variety of photosensitive materials. A composite scaffold made of distinct materials and periodicities is acquired after the development process used to wash out non-linked monomers. Another way to modify the 3D printed PLA surfaces was also demonstrated - ablation with femtosecond laser beam. Structure geometry on macro- to micro- scales could be finely tuned by combining these fabrication techniques. Such artificial 3D substrates could be used for cell growth or as biocompatible-biodegradable implants. To our best knowledge, this is the first experimental demonstration showing the creation of composite 3D scaffolds using convenient 3D printing combined with DLW. This combination of distinct material processing techniques enables rapid fabrication of diverse functional micro-featured and integrated devices. Hopefully, the proposed approach will find numerous applications in the field of tissue engineering, as well as in microelectromechanical systems, microfluidics, microoptics and others.

  5. Silicon-Embedding Approaches to 3-D Toroidal Inductor Fabrication

    SciTech Connect

    Yu, XH; Kim, M; Herrault, F; Ji, CH; Kim, J; Allen, MG

    2013-06-01

    This paper presents complementary-metal-oxide-semiconductor-compatible silicon-embedding techniques for on-chip integration of microelectromechanical-system devices with 3-D complex structures. By taking advantage of the "dead volume" within the bulk of the silicon wafer, functional devices with large profile can be embedded into the substrate without consuming valuable die area on the wafer surface or increasing the packaging complexity. Furthermore, through-wafer interconnects can be implemented to connect the device to the circuitry on the wafer surface. The key challenge of embedding structures within the wafer volume is processing inside deep trenches. To achieve this goal in an area-efficient manner, straight-sidewall trenches are desired, adding additional difficulty to the embedding process. Two approaches to achieve this goal are presented in this paper, i.e., a lithography-based process and a shadow-mask-based process. The lithography-based process utilizes a spray-coating technique and proximity lithography in combination with thick epoxy processing and laminated dry-film lithography. The shadow-mask-based process employs a specially designed 3-D silicon shadow mask to enable simultaneous metal patterning on both the vertical sidewall and the bottom surface of the trench during deposition, eliminating multiple lithography steps and reducing the process time. Both techniques have been demonstrated through the embedding of the topologically complex 3-D toroidal inductors into the silicon substrate for power supply on-chip (PwrSoC) applications. Embedded 3-D inductors that possess 25 turns and a diameter of 6 mm in a silicon trench of 300-mu m depth achieve overall inductances of 45-60 nH, dc resistances of 290-400 m Omega, and quality factors of 16-17.5 at 40-70 MHz.

  6. Use of Spray Adhesives for the Manufacture of 3-D Capillary Origami Microstructures

    NASA Astrophysics Data System (ADS)

    de Los Reyes, Mithi

    2011-10-01

    The method of ``capillary origami''---using the surface tension of an evaporating water droplet to fold a flexible membrane into a 3-D polyhedron, as investigated by Py et al.---has shown promise as a way to create fully 3-D microstructures. However, the origami re-opens past a critical evaporation point, and previous attempts to prevent this re-opening have proven to be expensive and time-consuming. We therefore investigated the use of various spray adhesives in keeping these origami microstructures closed. Three characteristics were measured: efficiency, tackiness, and strength of the adhesive. Measurements of these three characteristics point to 3M Super 77 Spray Adhesive as an optimal adhesive for spraying microstructures. Furthermore, we designed a new method to measure adhesive strength by using an analytical balance to measure force applied by a micrometer to a microstructure. We also developed novel procedures to create uniformly-sized microstructures and to accelerate the folding process, all of which improve upon the original capillary origami method. These novel procedures, combined with measurements that indicate 3M Super 77 as an optimum adhesive, suggest a potential method for the mass-production of truly 3-D microstructures. Py, Charlotte, et al. ``Capillary origami: Spontaneous wrapping of a droplet with an elastic sheet.'' Physical Review Letters. 98.156103 (2007)

  7. Fluorescence detector for capillary separations fabricated by 3D printing.

    PubMed

    Prikryl, Jan; Foret, Frantisek

    2014-12-16

    A simple inexpensive light-emitting diode (LED)-based fluorescence detector for detection in capillary separations is described. The modular design includes a separate high power LED source, detector head, designed in the epifluorescence arrangement, and capillary detection cells. The detector head and detection cells were printed using a 3D printer and assembled with commercially available optical components. Optical fibers were used for connecting the detector head to the LED excitation source and the photodetector module. Microscope objective or high numerical aperture optical fiber were used for collection of the fluorescence emission from the fused silica separation capillary. As an example, mixture of oligosaccharides labeled by 8-aminopyrene-1,3,6-trisulfonate (APTS) was separated by capillary zone electrophoresis and detected by the described detector. The performance of the detector was compared with both a semiconductor photodiode and photomultiplier as light sensing elements. The main advantages of the 3D printed parts, compared to the more expensive alternatives from the optic component suppliers, include not only cost reduction, but also easy customization of the spatial arrangement, modularity, miniaturization, and sharing of information between laboratories for easy replication or further modifications of the detector. All information and files necessary for printing the presented detector are enclosed in the Supporting Information. PMID:25427247

  8. Sloped irradiation techniques in deep x-ray lithography for 3D shaping of microstructures

    NASA Astrophysics Data System (ADS)

    Feiertag, Gregor; Ehrfeld, Wolfgang; Lehr, Heinz; Schmidt, Martin

    1997-07-01

    Deep x-ray lithography (DXRL) makes use of synchrotron radiation (SR) to transfer an absorber pattern from a mask into a thick resist layer. For most applications the direction of the SR beam is perpendicular to the mask and the resist plane. Subsequent replication techniques, e.g. electroforming, moulding or hot embossing, convert the resist relief obtained after development into micromechanical, microfluidic or micro- optical elements made from metals, polymers or ceramic materials. This process sequence is well known as the LIGA technique. The normal shadow printing process is complemented and enhanced by advanced techniques, e.g. by tilting the mask and the resist with respect to the SR beam or aligned multiple exposures to produce step-like structures. In this paper a technology for the fabrication of multidirectional inclined microstructures applying multiple tilted DXRL will be presented. Instead of one exposure with the mask/substrate assembly perpendicular to the SR beam, irradiation is performed several times applying tilt and rotational angles of the mask/substrate assembly relative to the SR beam. A huge variety of 3-D structures can be obtained using this technique. Some possible applications will be discussed.

  9. Fabrication of metallic microstructures by micromolding nanoparticles

    SciTech Connect

    Morales, Alfredo M.; Winter, Michael R.; Domeier, Linda A.; Allan, Shawn M.; Skala, Dawn M.

    2002-01-01

    A method is provided for fabricating metallic microstructures, i.e., microcomponents of micron or submicron dimensions. A molding composition is prepared containing an optional binder and nanometer size (1 to 1000 nm in diameter) metallic particles. A mold, such as a lithographically patterned mold, preferably a LIGA or a negative photoresist mold, is filled with the molding composition and compressed. The resulting microstructures are then removed from the mold and the resulting metallic microstructures so provided are then sintered.

  10. Hypereutectic AlSi Alloy: Gathering of 3D Microstructure Data

    NASA Astrophysics Data System (ADS)

    Schaberger-Zimmermann, E.; Mathes, M.; Zimmermann, G.

    2016-06-01

    Hypereutectic and eutectic AlSi-base alloys find frequent application in casting automotive components. The properties of this type of alloy depend significantly on their solidification microstructure, especially the size, shape, and distribution of primary and eutectic silicon. The serial sectioning technique was applied for determining the three-dimensional (3D) microstructure of an Al-18wt.%Si alloy. For clear identification of both the larger primary Si particles grown in the melt and the fine lamellar eutectic Si, a series of two-dimensional equidistant cross sections were metallographically prepared. The microstructure in these cross sections was detected and observed at high resolution using a light microscope. The images were stored in a digital library. The 3D reconstruction of primary Si particles and AlSi eutectic was achieved through the application of various software tools. This provided data about the faceted growth behavior of octahedral Si particles and feathery eutectic Si. The image stack was also imported to hierarchical data format (version 5) (HDF5) open source format, thus, enabling availability of the 3D image data to the wider community. In this way, 3D reconstructions of this kind can contribute to a greater understanding of processing/microstructure property relationships in hypereutectic AlSi alloys.

  11. Fabrication of three-dimensional multi-protein microstructures for cell migration and adhesion enhancement

    PubMed Central

    Da Sie, Yong; Li, Yi-Cheng; Chang, Nan-Shan; Campagnola, Paul J.; Chen, Shean-Jen

    2015-01-01

    In this study, three-dimensional (3D) multi-component microstructures were precisely fabricated via multiphoton excited photochemistry using a femtosecond laser direct-writing system with proposed repetition positioning and vector scanning techniques. Extracellular matrix (ECM) proteins, such as fibronectin (FN), are difficult to stack and form 3D structures larger than several-hundred microns in height due to the nature of their protein structure. Herein, to fabricate complex 3D microstructures with FN, a 3D scaffold was designed and formed from bovine serum albumin (BSA), after which human FN was inserted at specific locations on the BSA scaffold; in this manner, the fabricated ECM microstructure can guide cells in a 3D environment. A human breast cancer cell line, MDA-MB-231, was used to investigate the behavior of cell migration and adhesion on the fabricated human FN and BSA protein structures. Experimental results indicate that many cells are not able to attach or climb on a 3D structure’s inclined plane without FN support; hence, the influence of cell growth in a 3D context with FN should being taken into consideration. This 3D multi-protein fabrication technique holds potential for cell studies in designed complex 3D ECM scaffolds. PMID:25780738

  12. Tortuosity characterization of 3D microstructure at nano-scale for energy storage and conversion materials

    NASA Astrophysics Data System (ADS)

    Chen-Wiegart, Yu-chen Karen; DeMike, Ross; Erdonmez, Can; Thornton, Katsuyo; Barnett, Scott A.; Wang, Jun

    2014-03-01

    A distance propagation method is presented for calculating tortuosity with relatively low computation time from three-dimensional (3D) tomographic data. Moreover, a novel concept of tortuosity distribution is developed to provide a more comprehensive picture of inhomogeneous microstructures where tortuosity depends on the actual 3D paths. Instead of using one single tortuosity value, the tortuosity distribution both as spatial distribution map and also statistic histogram can provide a more complete description. The method, which can be applied to any porous medium, is tested against a diffusion-based tortuosity calculation on two 3D microstructures: a LiCoO2 cathode electrode of lithium ion battery measured by x-ray nano-tomography and a lanthanum strontium manganite-yttria-stabilized zirconia, solid oxide fuel cells cathode measured using focused ion beam-scanning electron microscopy serial sectioning. The present method is shown to provide good-agreement with the effective diffusion-based tortuosity values.

  13. Effects of changes in rock microstructures on permeability: 3-D printing investigation

    NASA Astrophysics Data System (ADS)

    Head, D.; Vanorio, T.

    2016-07-01

    Rocks are naturally heterogeneous; two rock samples with identical bulk properties can vary widely in microstructure. Understanding how the microstructure and bulk properties of rocks then evolve during experiments and computations simulating diagenesis is inherently a multiscale problem. The advent of modern 3-D printing has provided an unprecedented opportunity to link those scales by combining the strengths of digital and experimental rock physics. In this study, we take a computerized tomography-scanned model of a natural carbonate pore space then iteratively digitally manipulate, 3-D print, and measure the flow properties in the laboratory. This approach allows us to access multiple scales digitally and experimentally and test hypotheses about how changes in rock microstructure due to compaction and dissolution affect bulk transport properties in a repeatable manner.

  14. 3D microstructural and microchemical characteristics of SAFOD fault gouge: implications for understanding fault creep

    NASA Astrophysics Data System (ADS)

    Warr, Laurence; Wojatschke, Jasmaria; Carpenter, Brett; Marone, Chris; Schleicher, Anja; van der Pluijm, Ben

    2013-04-01

    Fault creep on the SAFOD section of the San Andreas Fault occurs along mechanically weak fault gouge characterized by high proportions of hydrous clay minerals, namely smectite, illite-smectite and chlorite-smectite phases. These minerals are concentrated along closely spaced, interconnected polished slip surfaces that give the gouge its characteristic scaly fabric. Although it is generally accepted that the creep behavior of the gouge relates to the concentration of these minerals, the precise mechanisms by which clay minerals weaken rock is currently a topic of debate. In this contribution we present the first results from a "slice-and-view" study of SAFOD gouge material by focused ion beam - scanning electron microscopy (Zeiss Auriga FIB/SEM), which allows the reconstruction of the microstructure and microchemistry of mineralized slip surfaces in 3D. The core and cuttings samples studied were selected from ca. 3297 m measured depth and represent some of the weakest materials yet recovered from the borehole, with a frictional coefficient of ca. 0.10 and a healing rate close to zero. This gouge contains abundant serpentine and smectite minerals, the latter of which was identified by X-ray diffraction to be saponite, after Mg- and glycol intercalation. Imaging and chemical analyses reveal nanometer scale thin alteration seams of saponite clay distributed throughout the ca. 50 micron thick sheared serpentinite layer that coats the slip surfaces. The base of this layer is defined by cataclastically deformed iron oxide minerals. The 3D fabric implies the orientation of the hydrated smectite minerals, which are interconnected and lie commonly sub parallel to the slip surface, are responsible for the gouge creep behavior in the laboratory. These minerals, and related interlayered varieties, are particularly weak due to their thin particle size and large quantities of adsorbed water, properties that are expected to persist down to mid-crustal depth (ca. 10 km). Creep of

  15. Optimizing fabrication of electrodeposited 3D surface features

    SciTech Connect

    Steffani, C., LLNL

    1998-07-01

    Selective electrodeposition onto specially masked surfaces (producing blind holes with non-conductive side walls) has been investigated. The thick masks are low cost polymer sheet into which holes and other patterns are machined. Plating with this type of masking system is one method of fabricating medium aspect ratio metallic structures (structures whose width to length ratio is greater than 10/1). The experiment was conducted with deposits of OFC copper from an acid sulfate solution, but similar results are expected with other metals. Structure diameter varied from 0.25 mm to 3.8 mm (0.01`` to 0.150``). The effect of current density, electrolyte concentration, solution temperature, and agitation on deposition rate were investigated. Deposit quality, deposition rate, and optimal plating parameters were evaluated.

  16. The fabrication of 3-D nanostructures by a low- voltage EBL

    NASA Astrophysics Data System (ADS)

    Oh, Seung Hun; Kim, Jae Gu; Kim, Chang Seok; Choi, Doo Sun; Chang, Sunghwan; Jeong, Myung Yung

    2011-02-01

    Three-dimensional (3-D) structures are used in many applications, including the fabrication of opto-electronic and bio-MEMS devices. Among the various fabrication techniques available for 3-D structures, nano imprint lithography (NIL) is preferred for producing nanoscale 3-D patterns because of its simplicity, relatively short processing time, and high manufacturing precision. For efficient replication in NIL, a precise 3-D stamp must be used as an imprinting tool. Hence, we attempted the fabrication of original 3-D master molds by low-voltage electron beam lithography (EBL). We then fabricated polydimethylsiloxane (PDMS) stamps from the original 3-D mold via replica molding with ultrasonic vibration.First, we experimentally analyzed the characteristics of low-voltage EBL in terms of various parameters such as resist thickness, acceleration voltage, aperture size, and baking temperature. From these e-beam exposure experiments, we found that the exposure depth and width were almost saturated at 3 kV or lesser, even when the electron dosage was increased. This allowed for the fabrication of various stepped 3-D nanostructures at a low voltage. In addition, by using line-dose EBL, V-groove patterns could be fabricated on a cured electron resist (ER) at a low voltage and low baking temperature. Finally, the depth variation could be controlled to within 10 nm through superposition exposure at 1 kV. From these results, we determined the optimum electron beam exposure conditions for the fabrication of various 3-D structures on ERs by low-voltage EBL. We then fabricated PDMS stamps via the replica molding process.

  17. Uncovering the true nature of deformation microstructures using 3D analysis methods

    NASA Astrophysics Data System (ADS)

    Ferry, M.; Quadir, M. Z.; Afrin, N.; Xu, W.; Loeb, A.; Soe, B.; McMahon, C.; George, C.; Bassman, L.

    2015-08-01

    Three-dimensional electron backscatter diffraction (3D EBSD) has emerged as a powerful technique for generating 3D crystallographic information in reasonably large volumes of a microstructure. The technique uses a focused ion beam (FIB) as a high precision serial sectioning device for generating consecutive ion milled surfaces of a material, with each milled surface subsequently mapped by EBSD. The successive EBSD maps are combined using a suitable post-processing method to generate a crystallographic volume of the microstructure. The first part of this paper shows the usefulness of 3D EBSD for understanding the origin of various structural features associated with the plastic deformation of metals. The second part describes a new method for automatically identifying the various types of low and high angle boundaries found in deformed and annealed metals, particularly those associated with grains exhibiting subtle and gradual variations in orientation. We have adapted a 2D image segmentation technique, fast multiscale clustering, to 3D EBSD data using a novel variance function to accommodate quaternion data. This adaptation is capable of segmenting based on subtle and gradual variation as well as on sharp boundaries within the data. We demonstrate the excellent capabilities of this technique with application to 3D EBSD data sets generated from a range of cold rolled and annealed metals described in the paper.

  18. Fine-tuned grayscale optofluidic maskless lithography for three-dimensional freeform shape microstructure fabrication.

    PubMed

    Song, Suk-Heung; Kim, Kibeom; Choi, Sung-Eun; Han, Sangkwon; Lee, Ho-Suk; Kwon, Sunghoon; Park, Wook

    2014-09-01

    This article presents free-floating three-dimensional (3D) microstructure fabrication in a microfluidic channel using direct fine-tuned grayscale image lithography. The image is designed as a freeform shape and is composed of gray shades as light-absorbing features. Gray shade levels are modulated through multiple reflections of light in a digital micromirror device (DMD) to produce different height formations. Whereas conventional photolithography has several limitations in producing grayscale colors on photomask features, our method focuses on a maskless, single-shot process for fabrication of freeform 3D micro-scale shapes. The fine-tuned gray image is designed using an 8-bit grayscale color; thus, each pixel is capable of displaying 256 gray shades. The pattern of the UV light reflecting on the DMD is transferred to a photocurable resin flowing through a microfluidic channel. Here, we demonstrate diverse free-floating 3D microstructure fabrication using fine-tuned grayscale image lithography. Additionally, we produce polymeric microstructures with locally embedded gray encoding patterns, such as grayscale-encoded microtags. This functional microstructure can be applied to a biophysical detection system combined with 3D microstructures. This method would be suitable for fabricating 3D microstructures that have a specific morphology to be used for particular biological or medical applications. PMID:25166099

  19. Digital microfabrication of user-defined 3D microstructures in cell-laden hydrogels.

    PubMed

    Soman, Pranav; Chung, Peter H; Zhang, A Ping; Chen, Shaochen

    2013-11-01

    Complex 3D interfacial arrangements of cells are found in several in vivo biosystems such as blood vasculature, renal glomeruli, and intestinal villi. Current tissue engineering techniques fail to develop suitable 3D microenvironments to evaluate the concurrent effects of complex topography and cell encapsulation. There is a need to develop new fabrication approaches that control cell density and distribution within complex 3D features. In this work, we present a dynamic projection printing process that allows rapid construction of complex 3D structures using custom-defined computer-aided-design (CAD) files. Gelatin-methacrylate (GelMA) constructs featuring user-defined spiral, pyramid, flower, and dome micro-geometries were fabricated with and without encapsulated cells. Encapsulated cells demonstrate good cell viability across all geometries both on the scaffold surface and internal to the structures. Cells respond to geometric cues individually as well as collectively throughout the larger-scale patterns. Time-lapse observations also reveal the dynamic nature of mechanical interactions between cells and micro-geometry. When compared to conventional cell-seeding, cell encapsulation within complex 3D patterned scaffolds provides long-term control over proliferation, cell morphology, and geometric guidance. Overall, this biofabrication technique offers a flexible platform to evaluate cell interactions with complex 3D micro-features, with the ability to scale-up towards high-throughput screening platforms. PMID:23686741

  20. Digital microfabrication of user-defined 3D microstructures in cell-laden hydrogels

    PubMed Central

    Soman, Pranav; Chung, Peter H.; Zhang, Alvin; Chen, Shaochen

    2013-01-01

    Complex 3D interfacial arrangements of cells are found in several in vivo biosystems such as blood vasculature, renal glomeruli, and intestinal villi. Current tissue engineering techniques fail to develop suitable 3D microenvironments to evaluate the concurrent effects of complex topography and cell encapsulation. There is a need to develop new fabrication approaches that control cell density and distribution within complex 3D features. In this work, we present a dynamic projection printing process that allows rapid construction of complex 3D structures using custom-defined computer-aided-design (CAD) files. Gelatin-methacrylate (GelMA) constructs featuring user-defined spiral, pyramid, flower, and dome micro-geometries were fabricated with and without encapsulated cells. Encapsulated cells demonstrate good cell viability across all geometries both on the scaffold surface and internal to the structures. Cells respond to geometric cues individually as well as collectively throughout the larger-scale patterns. Time-lapse observations also reveal the dynamic nature of mechanical interactions between cells and micro-geometry. When compared to conventional cell-seeding, cell encapsulation within complex 3D patterned scaffolds provides long-term control over proliferation, cell morphology, and geometric guidance. Overall, this biofabrication technique offers a flexible platform to evaluate cell interactions with complex 3D micro-features, with the ability to scale-up towards high-throughput screening platforms. PMID:23686741

  1. Sacrificial Template Synthesis and Properties of 3D Hollow-Silicon Nano- and Microstructures.

    PubMed

    Hölken, Iris; Neubüser, Gero; Postica, Vasile; Bumke, Lars; Lupan, Oleg; Baum, Martina; Mishra, Yogendra Kumar; Kienle, Lorenz; Adelung, Rainer

    2016-08-10

    Novel three-dimensional (3D) hollow aero-silicon nano- and microstructures, namely, Si-tetrapods (Si-T) and Si-spheres (Si-S) were synthesized by a sacrificial template approach for the first time. The new Si-T and Si-S architectures were found as most temperature-stable hollow nanomaterials, up to 1000 °C, ever reported. The synthesized aero-silicon or aerogel was integrated into sensor structures based on 3D networks. A single microstructure Si-T was employed to investigate electrical and gas sensing properties. The elaborated hollow microstructures open new possibilities and a wide area of perspectives in the field of nano- and microstructure synthesis by sacrificial template approaches. The enormous flexibility and variety of the hollow Si structures are provided by the special geometry of the sacrificial template material, ZnO-tetrapods (ZnO-T). A Si layer was deposited onto the surface of ZnO-T networks by plasma-enhanced chemical vapor deposition. All samples demonstrated p-type conductivity; hence, the resistance of the sensor structure increased after introducing the reducing gases in the test chamber. These hollow structures and their unique and superior properties can be advantageous in different fields, such as NEMS/MEMS, batteries, dye-sensitized solar cells, gas sensing in harsh environment, and biomedical applications. This method can be extended for synthesis of other types of hollow nanostructures. PMID:27428091

  2. Fabrication of 3D solenoid microcoils in silica glass by femtosecond laser wet etch and microsolidics

    NASA Astrophysics Data System (ADS)

    Meng, Xiangwei; Yang, Qing; Chen, Feng; Shan, Chao; Liu, Keyin; Li, Yanyang; Bian, Hao; Du, Guangqing; Hou, Xun

    2015-02-01

    This paper reports a flexible fabrication method for 3D solenoid microcoils in silica glass. The method consists of femtosecond laser wet etching (FLWE) and microsolidics process. The 3D microchannel with high aspect ratio is fabricated by an improved FLWE method. In the microsolidics process, an alloy was chosen as the conductive metal. The microwires are achieved by injecting liquid alloy into the microchannel, and allowing the alloy to cool and solidify. The alloy microwires with high melting point can overcome the limitation of working temperature and improve the electrical property. The geometry, the height and diameter of microcoils were flexibly fabricated by the pre-designed laser writing path, the laser power and etching time. The 3D microcoils can provide uniform magnetic field and be widely integrated in many magnetic microsystems.

  3. Development of an indirect solid freeform fabrication process based on microstereolithography for 3D porous scaffolds

    NASA Astrophysics Data System (ADS)

    Kang, Hyun-Wook; Seol, Young-Joon; Cho, Dong-Woo

    2009-01-01

    Scaffold fabrication using solid freeform fabrication (SFF) technology is a hot topic in tissue engineering. Here, we present a new indirect SFF technology based on microstereolithography (MSTL), which has the highest resolution of all SFF methods, to construct a three-dimensional (3D) porous scaffold by combining SFF with molding technology. To realize this indirect method, we investigated and modified a water-soluble photopolymer. We used MSTL technology to fabricate a high-resolution 3D porous mold composed of the modified polymer. The mold can be removed using an appropriate solvent. We tested two materials, polycaprolactone and calcium sulfate hemihydrate, using the molding process, and developed a lost-mold shape forming process by dissolving the mold. This procedure demonstrated that the proposed method can yield scaffold pore sizes as small as 60-70 µm. In addition, cytotoxicity test results indicated that the proposed process is feasible for producing 3D porous scaffolds.

  4. Calculation of grain boundary normals directly from 3D microstructure images

    SciTech Connect

    Lieberman, E. J.; Rollett, A. D.; Lebensohn, R. A.; Kober, E. M.

    2015-03-11

    The determination of grain boundary normals is an integral part of the characterization of grain boundaries in polycrystalline materials. These normal vectors are difficult to quantify due to the discretized nature of available microstructure characterization techniques. The most common method to determine grain boundary normals is by generating a surface mesh from an image of the microstructure, but this process can be slow, and is subject to smoothing issues. A new technique is proposed, utilizing first order Cartesian moments of binary indicator functions, to determine grain boundary normals directly from a voxelized microstructure image. In order to validate the accuracy of this technique, the surface normals obtained by the proposed method are compared to those generated by a surface meshing algorithm. Specifically, the local divergence between the surface normals obtained by different variants of the proposed technique and those generated from a surface mesh of a synthetic microstructure constructed using a marching cubes algorithm followed by Laplacian smoothing is quantified. Next, surface normals obtained with the proposed method from a measured 3D microstructure image of a Ni polycrystal are used to generate grain boundary character distributions (GBCD) for Σ3 and Σ9 boundaries, and compared to the GBCD generated using a surface mesh obtained from the same image. Finally, the results show that the proposed technique is an efficient and accurate method to determine voxelized fields of grain boundary normals.

  5. Calculation of grain boundary normals directly from 3D microstructure images

    DOE PAGESBeta

    Lieberman, E. J.; Rollett, A. D.; Lebensohn, R. A.; Kober, E. M.

    2015-03-11

    The determination of grain boundary normals is an integral part of the characterization of grain boundaries in polycrystalline materials. These normal vectors are difficult to quantify due to the discretized nature of available microstructure characterization techniques. The most common method to determine grain boundary normals is by generating a surface mesh from an image of the microstructure, but this process can be slow, and is subject to smoothing issues. A new technique is proposed, utilizing first order Cartesian moments of binary indicator functions, to determine grain boundary normals directly from a voxelized microstructure image. In order to validate the accuracymore » of this technique, the surface normals obtained by the proposed method are compared to those generated by a surface meshing algorithm. Specifically, the local divergence between the surface normals obtained by different variants of the proposed technique and those generated from a surface mesh of a synthetic microstructure constructed using a marching cubes algorithm followed by Laplacian smoothing is quantified. Next, surface normals obtained with the proposed method from a measured 3D microstructure image of a Ni polycrystal are used to generate grain boundary character distributions (GBCD) for Σ3 and Σ9 boundaries, and compared to the GBCD generated using a surface mesh obtained from the same image. Finally, the results show that the proposed technique is an efficient and accurate method to determine voxelized fields of grain boundary normals.« less

  6. 3D printed auxetic forms on knitted fabrics for adjustable permeability and mechanical properties

    NASA Astrophysics Data System (ADS)

    Grimmelsmann, N.; Meissner, H.; Ehrmann, A.

    2016-07-01

    The 3D printing technology can be applied into manufacturing primary shaping diverse products, from models dealing as examples for future products that will be produced with another technique, to useful objects. Since 3D printing is nowadays significantly slower than other possibilities to manufacture items, such as die casting, it is often used for small parts that are produced in small numbers or for products that cannot be created in another way. Combinations of 3D printing with other objects, adding novel functionalities to them, are thus favourable to a complete primary shaping process. Textile fabrics belong to the objects whose mechanical and other properties can notably be modified by adding 3D printed forms. This article mainly reports on a new possibility to change the permeability of textile fabrics by 3D printing auxetic forms, e.g. for utilising them in textile filters. In addition, auxetic forms 3D printed on knitted fabrics can bring about mechanical properties that are conducive to tensile constructions.

  7. Novel Target Fabrication Using 3D Printing Developed at University of Michigan

    NASA Astrophysics Data System (ADS)

    Klein, Sallee R.; Deininger, Michael; Gillespie, Robb S.; Di Stefano, Carlos A.; MacDonald, Michael J.; J-E Manuel, Mario; Young, Rachel P.; Kuranz, Carolyn C.; Keiter, Paul A.; Drake, R. Paul

    2016-04-01

    The University of Michigan has been fabricating targets for high-energy-density experiments for the past decade. We utilize the technique of machined acrylic bodies and mating components acting as constraints to build repeatable targets. Combining 3D printing with traditional machining, we are able to take advantage of the very best part of both aspects of manufacturing. Here we present several recent campaigns to act as showcase and introduction of our techniques and our experience with 3D printing, effecting how we utilize 3D printing in our target builds.

  8. A Review on Energy Harvesting Using 3D Printed Fabrics for Wearable Electronics

    NASA Astrophysics Data System (ADS)

    Gowthaman, Swaminathan; Chidambaram, Gowri Shankar; Rao, Dilli Babu Govardhana; Subramya, Hemakumar Vyudhayagiri; Chandrasekhar, Udhayagiri

    2016-06-01

    Embedding of energy harvesting systems into wearable health and environment monitoring systems, like integration of smart piezoelectric fibers into soldier fabric structures opens up avenues in generating electricity from natural mechanical movements for self-powering of wearable electronics. Emergence of multitudinous of materials and manufacturing technologies has enabled realization of various energy harvesting systems from mechanical movements. The materials and manufacturing related to 3D printing of energy harvesting fabrics are reviewed in this paper. State-of-the-art energy harvesting sources are briefly described following which an in-depth analysis on the materials and 3D printing techniques for energy harvesting fabrics are presented. While tremendous motivation and opportunity exists for wider-scale adoption of 3D printing for this niche area, the success depends on efficient design of three critical factors namely materials, process and structure. The present review discusses on the complex issues of materials selection, modelling and processing of 3D printed fabrics. The paper culminates by presenting a discussion on how future advancements in 3D printing technology might be useful for development of wearable electronics.

  9. First direct 3D visualisation of microstructural evolutions during sintering through X-ray computed microtomography

    SciTech Connect

    Bernard, Dominique . E-mail: bernard@icmcb.u-bordeaux.fr; Gendron, Damien; Heintz, Jean-Marc; Bordere, Sylvie; Etourneau, Jean

    2005-01-03

    X-ray computed microtomography (XCMT) has been applied to ceramic samples of different materials to visualise, for the first time at this scale, real 3D microstructural evolutions during sintering. Using this technique, it has been possible to follow the whole sintering process of the same grains set. Two materials have been studied; a glass powder heat treated at 700 deg. C and a crystallised lithium borate (Li{sub 6}Gd(BO{sub 3}){sub 3}) powder heat treated at 720 deg. C. XCMT measurements have been done after different sintering times. For each material, a sub-volume was individualised and localised on the successive recordings and its 3D images numerically reconstructed. Description of the three-dimensional microstructures evolution is proposed. From the 3D experimental data, quantitative evolutions of parameters such as porosity and neck size are presented for the glass sample. Possibilities offered by this technique to study complex sintering processes, as for lithium borate, are illustrated.

  10. Efficient fabrication method of nano-grating for 3D holographic display with full parallax views.

    PubMed

    Wan, Wenqiang; Qiao, Wen; Huang, Wenbin; Zhu, Ming; Fang, Zongbao; Pu, Donglin; Ye, Yan; Liu, Yanhua; Chen, Linsen

    2016-03-21

    Without any special glasses, multiview 3D displays based on the diffractive optics can present high resolution, full-parallax 3D images in an ultra-wide viewing angle. The enabling optical component, namely the phase plate, can produce arbitrarily distributed view zones by carefully designing the orientation and the period of each nano-grating pixel. However, such 3D display screen is restricted to a limited size due to the time-consuming fabricating process of nano-gratings on the phase plate. In this paper, we proposed and developed a lithography system that can fabricate the phase plate efficiently. Here we made two phase plates with full nano-grating pixel coverage at a speed of 20 mm2/mins, a 500 fold increment in the efficiency when compared to the method of E-beam lithography. One 2.5-inch phase plate generated 9-view 3D images with horizontal-parallax, while the other 6-inch phase plate produced 64-view 3D images with full-parallax. The angular divergence in horizontal axis and vertical axis was 1.5 degrees, and 1.25 degrees, respectively, slightly larger than the simulated value of 1.2 degrees by Finite Difference Time Domain (FDTD). The intensity variation was less than 10% for each viewpoint, in consistency with the simulation results. On top of each phase plate, a high-resolution binary masking pattern containing amplitude information of all viewing zone was well aligned. We achieved a resolution of 400 pixels/inch and a viewing angle of 40 degrees for 9-view 3D images with horizontal parallax. In another prototype, the resolution of each view was 160 pixels/inch and the view angle was 50 degrees for 64-view 3D images with full parallax. As demonstrated in the experiments, the homemade lithography system provided the key fabricating technology for multiview 3D holographic display. PMID:27136814

  11. Formation of Neural Networks in 3D Scaffolds Fabricated by Means of Laser Microstereolithography.

    PubMed

    Vedunova, M V; Timashev, P S; Mishchenko, T A; Mitroshina, E V; Koroleva, A V; Chichkov, B N; Panchenko, V Ya; Bagratashvili, V N; Mukhina, I V

    2016-08-01

    We developed and tested new 3D scaffolds for neurotransplantation. Scaffolds of predetermined architectonic were prepared using microstereolithography technique. Scaffolds were highly biocompatible with the nervous tissue cells. In vitro studies showed that the material of fabricated scaffolds is not toxic for dissociated brain cells and promotes the formation of functional neural networks in the matrix. These results demonstrate the possibility of fabrication of tissue-engineering constructs for neurotransplantation based on created scaffolds. PMID:27595153

  12. Microstructure analysis of the secondary pulmonary lobules by 3D synchrotron radiation CT

    NASA Astrophysics Data System (ADS)

    Fukuoka, Y.; Kawata, Y.; Niki, N.; Umetani, K.; Nakano, Y.; Ohmatsu, H.; Moriyama, N.; Itoh, H.

    2014-03-01

    Recognition of abnormalities related to the lobular anatomy has become increasingly important in the diagnosis and differential diagnosis of lung abnormalities at clinical routines of CT examinations. This paper aims a 3-D microstructural analysis of the pulmonary acinus with isotropic spatial resolution in the range of several micrometers by using micro CT. Previously, we demonstrated the ability of synchrotron radiation micro CT (SRμCT) using offset scan mode in microstructural analysis of the whole part of the secondary pulmonary lobule. In this paper, we present a semiautomatic method to segment the acinar and subacinar airspaces from the secondary pulmonary lobule and to track small vessels running inside alveolar walls in human acinus imaged by the SRμCT. The method beains with and segmentation of the tissues such as pleural surface, interlobular septa, alveola wall, or vessel using a threshold technique and 3-D connected component analysis. 3-D air space are then conustructed separated by tissues and represented branching patterns of airways and airspaces distal to the terminal bronchiole. A graph-partitioning approach isolated acini whose stems are interactively defined as the terminal bronchiole in the secondary pulmonary lobule. Finally, we performed vessel tracking using a non-linear sate space which captures both smoothness of the trajectories and intensity coherence along vessel orientations. Results demonstrate that the proposed method can extract several acinar airspaces from the 3-D SRμCT image of secondary pulmonary lobule and that the extracted acinar airspace enable an accurate quantitative description of the anatomy of the human acinus for interpretation of the basic unit of pulmonary structure and function.

  13. Fabrication of 3D high aspect ratio PDMS microfluidic networks with a hybrid stamp.

    PubMed

    Kung, Yu-Chun; Huang, Kuo-Wei; Fan, Yu-Jui; Chiou, Pei-Yu

    2015-04-21

    We report a novel methodology for fabricating large-area, multilayer, thin-film, high aspect ratio, 3D microfluidic structures with through-layer vias and open channels that can be bonded between hard substrates. It is realized by utilizing a hybrid stamp with a thin plastic sheet embedded underneath a PDMS surface. This hybrid stamp solves an important edge protrusion issue during PDMS molding while maintaining necessary stamp elasticity to ensure the removal of PDMS residues at through-layer regions. Removing edge protrusion is a significant progress toward fabricating 3D structures since high aspect ratio PDMS structures with flat interfaces can be realized to facilitate multilayer stacking and bonding to hard substrates. Our method also allows for the fabrication of 3D deformable channels, which can lead to profound applications in electrokinetics, optofluidics, inertial microfluidics, and other fields where the shape of the channel cross section plays a key role in device physics. To demonstrate, as an example, we have fabricated a microfluidic channel by sandwiching two 20 μm wide, 80 μm tall PDMS membranes between two featureless ITO glass substrates. By applying electrical bias to the two ITO substrates and pressure to deform the thin membrane sidewalls, strong electric field enhancement can be generated in the center of a channel to enable 3D sheathless dielectrophoretic focusing of biological objects including mammalian cells and bacteria at a flow speed up to 14 cm s(-1). PMID:25710255

  14. Formation and properties of 3D metamaterial composites fabricated using nanometer scale laser lithography (Presentation Recording)

    NASA Astrophysics Data System (ADS)

    Prokes, Sharka M.; Perkins, Frank K.; Glembocki, Orest J.

    2015-08-01

    Metamaterials designed for the visible or near IR wavelengths require patterning on the nanometer scale. To achieve this, e-beam lithography is used, but it is extremely difficult and can only produce 2D structures. A new alternative technique to produce 2D and 3D structures involves laser fabrication using the Nanoscribe 3D laser lithography system. This is a direct laser writing technique which can form arbitrary 3D nanostructures on the nanometer scale and is based on multi-photon polymerization. We are creating 2D and 3D metamaterials via this technique, and subsequently conformally coating them using Atomic Layer Deposition of oxides and Ag. We will discuss the optical properties of these novel composite structures and their potential for dual resonant metamaterials.

  15. Fabrication, Characterization, And Deformation of 3D Structural Meta-Materials

    NASA Astrophysics Data System (ADS)

    Montemayor, Lauren C.

    Current technological advances in fabrication methods have provided pathways to creating architected structural meta-materials similar to those found in natural organisms that are structurally robust and lightweight, such as diatoms. Structural meta-materials are materials with mechanical properties that are determined by material properties at various length scales, which range from the material microstructure (nm) to the macro-scale architecture (mum -- mm). It is now possible to exploit material size effect, which emerge at the nanometer length scale, as well as structural effects to tune the material properties and failure mechanisms of small-scale cellular solids, such as nanolattices. This work demonstrates the fabrication and mechanical properties of 3-dimensional hollow nanolattices in both tension and compression. Hollow gold nanolattices loaded in uniaxial compression demonstrate that strength and stiffness vary as a function of geometry and tube wall thickness. Structural effects were explored by increasing the unit cell angle from 30° to 60° while keeping all other parameters constant; material size effects were probed by varying the tube wall thickness, t, from 200nm to 635nm, at a constant relative density and grain size. In-situ uniaxial compression experiments reveal an order-of-magnitude increase in yield stress and modulus in nanolattices with greater lattice angles, and a 150% increase in the yield strength without a concomitant change in modulus in thicker-walled nanolattices for fixed lattice angles. These results imply that independent control of structural and material size effects enables tunability of mechanical properties of 3-dimensional architected meta-materials and highlight the importance of material, geometric, and microstructural effects in small-scale mechanics. This work also explores the flaw tolerance of 3D hollow-tube alumina kagome nanolattices with and without pre-fabricated notches, both in experiment and simulation

  16. Fabrication of low cost soft tissue prostheses with the desktop 3D printer

    PubMed Central

    He, Yong; Xue, Guang-huai; Fu, Jian-zhong

    2014-01-01

    Soft tissue prostheses such as artificial ear, eye and nose are widely used in the maxillofacial rehabilitation. In this report we demonstrate how to fabricate soft prostheses mold with a low cost desktop 3D printer. The fabrication method used is referred to as Scanning Printing Polishing Casting (SPPC). Firstly the anatomy is scanned with a 3D scanner, then a tissue casting mold is designed on computer and printed with a desktop 3D printer. Subsequently, a chemical polishing method is used to polish the casting mold by removing the staircase effect and acquiring a smooth surface. Finally, the last step is to cast medical grade silicone into the mold. After the silicone is cured, the fine soft prostheses can be removed from the mold. Utilizing the SPPC method, soft prostheses with smooth surface and complicated structure can be fabricated at a low cost. Accordingly, the total cost of fabricating ear prosthesis is about $30, which is much lower than the current soft prostheses fabrication methods. PMID:25427880

  17. Fabrication of low cost soft tissue prostheses with the desktop 3D printer

    NASA Astrophysics Data System (ADS)

    He, Yong; Xue, Guang-Huai; Fu, Jian-Zhong

    2014-11-01

    Soft tissue prostheses such as artificial ear, eye and nose are widely used in the maxillofacial rehabilitation. In this report we demonstrate how to fabricate soft prostheses mold with a low cost desktop 3D printer. The fabrication method used is referred to as Scanning Printing Polishing Casting (SPPC). Firstly the anatomy is scanned with a 3D scanner, then a tissue casting mold is designed on computer and printed with a desktop 3D printer. Subsequently, a chemical polishing method is used to polish the casting mold by removing the staircase effect and acquiring a smooth surface. Finally, the last step is to cast medical grade silicone into the mold. After the silicone is cured, the fine soft prostheses can be removed from the mold. Utilizing the SPPC method, soft prostheses with smooth surface and complicated structure can be fabricated at a low cost. Accordingly, the total cost of fabricating ear prosthesis is about $30, which is much lower than the current soft prostheses fabrication methods.

  18. Effect of Frictions on the Ballistic Performance of a 3D Warp Interlock Fabric: Numerical Analysis

    NASA Astrophysics Data System (ADS)

    Ha-Minh, Cuong; Boussu, François; Kanit, Toufik; Crépin, David; Imad, Abdellatif

    2012-06-01

    3D interlock woven fabrics are promising materials to replace the 2D structures in the field of ballistic protection. The structural complexity of this material caused many difficulties in numerical modeling. This paper presents a new tool that permits to generate a geometry model of any woven fabric, then, mesh this model in shell or solid elements, and apply the mechanical properties of yarns to them. The tool shows many advantages over existing software. It is very handy in use with an organization of the functions in menu and using a graphic interface. It can describe correctly the geometry of all textile woven fabrics. With this tool, the orientation of the local axes of finite elements following the yarn direction facilitates defining the yarn mechanical properties in a numerical model. This tool can be largely applied because it is compatible with popular finite element codes such as Abaqus, Ansys, Radioss etc. Thanks to this tool, a finite element model was carried out to describe a ballistic impact on a 3D warp interlock Kevlar KM2® fabric. This work focuses on studying the effect of friction onto the ballistic impact behavior of this textile interlock structure. Results showed that the friction among yarns affects considerably on the impact behavior of this fabric. The effect of the friction between projectile and yarn is less important. The friction plays an important role in keeping the fabric structural stability during the impact event. This phenomenon explained why the projectile is easier to penetrate this 3D warp interlock fabric in the no-friction case. This result also indicates that the ballistic performance of the interlock woven fabrics can be improved by using fibers with great friction coefficients.

  19. 3D Scaffolds with Different Stiffness but the Same Microstructure for Bone Tissue Engineering.

    PubMed

    Chen, Guobao; Dong, Chanjuan; Yang, Li; Lv, Yonggang

    2015-07-29

    A growing body of evidence has shown that extracellular matrix (ECM) stiffness can modulate stem cell adhesion, proliferation, migration, differentiation, and signaling. Stem cells can feel and respond sensitively to the mechanical microenvironment of the ECM. However, most studies have focused on classical two-dimensional (2D) or quasi-three-dimensional environments, which cannot represent the real situation in vivo. Furthermore, most of the current methods used to generate different mechanical properties invariably change the fundamental structural properties of the scaffolds (such as morphology, porosity, pore size, and pore interconnectivity). In this study, we have developed novel three-dimensional (3D) scaffolds with different degrees of stiffness but the same 3D microstructure that was maintained by using decellularized cancellous bone. Mixtures of collagen and hydroxyapatite [HA: Ca10(PO4)6(OH)2] with different proportions were coated on decellularized cancellous bone to vary the stiffness (local stiffness, 13.00 ± 5.55 kPa, 13.87 ± 1.51 kPa, and 37.7 ± 19.6 kPa; bulk stiffness, 6.74 ± 1.16 kPa, 8.82 ± 2.12 kPa, and 23.61 ± 8.06 kPa). Microcomputed tomography (μ-CT) assay proved that there was no statistically significant difference in the architecture of the scaffolds before or after coating. Cell viability, osteogenic differentiation, cell recruitment, and angiogenesis were determined to characterize the scaffolds and evaluate their biological responses in vitro and in vivo. The in vitro results indicate that the scaffolds developed in this study could sustain adhesion and growth of rat mesenchymal stem cells (MSCs) and promote their osteogenic differentiation. The in vivo results further demonstrated that these scaffolds could help to recruit MSCs from subcutaneous tissue, induce them to differentiate into osteoblasts, and provide the 3D environment for angiogenesis. These findings showed that the method we developed can build scaffolds with

  20. Micro-structured materials and mechanical cues in 3D collagen gels.

    PubMed

    Phillips, James B; Brown, Robert

    2011-01-01

    Collagen gels provide a versatile and widely used substrate for three-dimensional (3D) cell culture. Here we describe how cell-seeded Type-I collagen gels can be adapted to provide powerful 3D models to support a wide range of research applications where cell/substrate alignment, density, stiffness/compliance, and strain are critical factors. In their fully hydrated form, rectangular collagen gels can be tethered such that endogenous forces generated as resident cells attach to and remodel the fibrillar collagen network can align the substrate in a controllable, predictable, and quantifiable manner. By removing water from collagen gels (plastic compression), their density increases towards that of body tissues, facilitating the engineering of a range of biomimetic constructs with controllable mechanical properties. This dense collagen can be used in combination with other components to achieve a range of functional properties from controlled perfusion, or tensile/compressive strength to new micro-structures. Detailed methodology is provided for the assembly of a range of 3D collagen materials including tethered aligned hydrogels and plastic compressed constructs. A range of techniques for analysing cell behaviour within these models, including microscopy and molecular analyses are described. These systems therefore provide a highly controllable mechanical and chemical micro-environment for investigating a wide range of cellular responses. PMID:21042973

  1. Fabrication of 3D microfluidic structures inside glass by femtosecond laser micromachining

    NASA Astrophysics Data System (ADS)

    Sugioka, Koji; Cheng, Ya

    2014-01-01

    Femtosecond lasers have opened up new avenues in materials processing due to their unique characteristics of ultrashort pulse widths and extremely high peak intensities. One of the most important features of femtosecond laser processing is that a femtosecond laser beam can induce strong absorption in even transparent materials due to nonlinear multiphoton absorption. This makes it possible to directly create three-dimensional (3D) microfluidic structures in glass that are of great use for fabrication of biochips. For fabrication of the 3D microfluidic structures, two technical approaches are being attempted. One of them employs femtosecond laser-induced internal modification of glass followed by wet chemical etching using an acid solution (Femtosecond laser-assisted wet chemical etching), while the other one performs femtosecond laser 3D ablation of the glass in distilled water (liquid-assisted femtosecond laser drilling). This paper provides a review on these two techniques for fabrication of 3D micro and nanofluidic structures in glass based on our development and experimental results.

  2. Modelling mesoporous alumina microstructure with 3D random models of platelets.

    PubMed

    Wang, H; Pietrasanta, A; Jeulin, D; Willot, F; Faessel, M; Sorbier, L; Moreaud, M

    2015-12-01

    This work focuses on a mesoporous material made up of nanometric alumina 'platelets' of unknown shape. We develope a 3D random microstructure to model the porous material, based on 2D transmission electron microscopy (TEM) images, without prior knowledge on the spatial distribution of alumina inside the material. The TEM images, acquired on samples with thickness 300 nm, a scale much larger than the platelets's size, are too blurry and noisy to allow one to distinguish platelets or platelets aggregates individually. In a first step, the TEM images correlation function and integral range are estimated. The presence of long-range fluctuations, due to the TEM inhomogeneous detection, is detected and corrected by filtering. The corrected correlation function is used as a morphological descriptor for the model. After testing a Boolean model of platelets, a two-scale model of microstructure is introduced to replicate the statistical dispersion of platelets observed on TEM images. Accordingly, a set of two-scale Boolean models with varying physically admissible platelets shapes is proposed. Upon optimization, the model takes into account the dispersion of platelets in the microstructure as observed on TEM images. Comparing it to X-ray diffraction and nitrogen porosimetry data, the model is found to be in good agreement with the material in terms of specific surface area. PMID:26280446

  3. A Patterned 3D Silicon Anode Fabricated by Electrodeposition on a Virus-Structured Current Collector

    SciTech Connect

    Chen, X L; Gerasopoulos, K; Guo, J C; Brown, A; Wang, Chunsheng; Ghodssi, Reza; Culver, J N

    2010-11-09

    Electrochemical methods were developed for the deposition of nanosilicon onto a 3D virus-structured nickel current collector. This nickel current collector is composed of self-assembled nanowire-like rods of genetically modified tobacco mosaic virus (TMV1cys), chemically coated in nickel to create a complex high surface area conductive substrate. The electrochemically depo­sited 3D silicon anodes demonstrate outstanding rate performance, cycling stability, and rate capability. Electrodeposition thus provides a unique means of fabricating silicon anode materials on complex substrates at low cost.

  4. 3D scanning and 3D printing as innovative technologies for fabricating personalized topical drug delivery systems.

    PubMed

    Goyanes, Alvaro; Det-Amornrat, Usanee; Wang, Jie; Basit, Abdul W; Gaisford, Simon

    2016-07-28

    Acne is a multifactorial inflammatory skin disease with high prevalence. In this work, the potential of 3D printing to produce flexible personalised-shape anti-acne drug (salicylic acid) loaded devices was demonstrated by two different 3D printing (3DP) technologies: Fused Deposition Modelling (FDM) and stereolithography (SLA). 3D scanning technology was used to obtain a 3D model of a nose adapted to the morphology of an individual. In FDM 3DP, commercially produced Flex EcoPLA™ (FPLA) and polycaprolactone (PCL) filaments were loaded with salicylic acid by hot melt extrusion (HME) (theoretical drug loading - 2% w/w) and used as feedstock material for 3D printing. Drug loading in the FPLA-salicylic acid and PCL-salicylic acid 3D printed patches was 0.4% w/w and 1.2% w/w respectively, indicating significant thermal degradation of drug during HME and 3D printing. Diffusion testing in Franz cells using a synthetic membrane revealed that the drug loaded printed samples released <187μg/cm(2) within 3h. FPLA-salicylic acid filament was successfully printed as a nose-shape mask by FDM 3DP, but the PCL-salicylic acid filament was not. In the SLA printing process, the drug was dissolved in different mixtures of poly(ethylene glycol) diacrylate (PEGDA) and poly(ethylene glycol) (PEG) that were solidified by the action of a laser beam. SLA printing led to 3D printed devices (nose-shape) with higher resolution and higher drug loading (1.9% w/w) than FDM, with no drug degradation. The results of drug diffusion tests revealed that drug diffusion was faster than with the FDM devices, 229 and 291μg/cm(2) within 3h for the two formulations evaluated. In this study, SLA printing was the more appropriate 3D printing technology to manufacture anti-acne devices with salicylic acid. The combination of 3D scanning and 3D printing has the potential to offer solutions to produce personalised drug loaded devices, adapted in shape and size to individual patients. PMID:27189134

  5. A simple approach for the fabrication of 3D microelectrodes for impedimetric sensing

    NASA Astrophysics Data System (ADS)

    Tahsin Guler, Mustafa; Bilican, Ismail; Agan, Sedat; Elbuken, Caglar

    2015-09-01

    In this paper, we present a very simple method to fabricate three-dimensional (3D) microelectrodes integrated with microfluidic devices. We form the electrodes by etching a microwire placed across a microchannel. For precise control of the electrode spacing, we employ a hydrodynamic focusing microfluidic device and control the width of the etching solution stream. The focused widths of the etchant solution and the etching time determine the gap formed between the electrodes. Using the same microfluidic device, we can fabricate integrated 3D electrodes with different electrode gaps. We have demonstrated the functionality of these electrodes using an impedimetric particle counting setup. Using 3D microelectrodes with a diameter of 25 μm, we have detected 6 μm-diameter polystyrene beads in a buffer solution as well as erythrocytes in a PBS solution. We study the effect of electrode spacing on the signal-to-noise ratio of the impedance signal and we demonstrate that the smaller the electrode spacing the higher the signal obtained from a single microparticle. The sample stream is introduced to the system using the same hydrodynamic focusing device, which ensures the alignment of the sample in between the electrodes. Utilising a 3D hydrodynamic focusing approach, we force all the particles to go through the sensing region of the electrodes. This fabrication scheme not only provides a very low-cost and easy method for rapid prototyping, but which can also be used for applications requiring 3D electric field focused through a narrow section of the microchannel.

  6. Micro-EDM for silicon microstructure fabrication

    NASA Astrophysics Data System (ADS)

    Song, Xiaozhong; Reynaerts, Dominiek; Meeusen, Wim; Van Brussel, Hendrik

    1999-03-01

    Currently, most silicon microstructures used in microstructures are produced by photolithographic methods. The reason for this is the well-developed etching technology, used in microelectronics, that has been transferred to the microsystem domain. But since the making of an arbitrary shape or angle on silicon mainly depends on the crystal orientation, some severe limits exist in the production of 3D structures. Electro-discharge machining (EDM) is basically a thermal process. During the EDM process material is removed by electric sparking. It is therefore completely different from etching. In this work, micro-EDM is introduce as a potential approach for solving the above mentioned drawbacks. First, this work presents several testing experiments with different process parameters to investigate the influence of the micro-EDM process on the silicon structure. Main emphasis is put on the surface roughness and on avoiding microcracks generated by the sparking process. It is found that microstructures with a sufficiently low surface roughness and with small microcracks can be produced. The remainder of the work concentrates on making small beam structures, which is a common structure in many microsensor designs. It is found that for a wafer thickness of 650 micrometers , the thinnest beam that can be produced is about 30 micrometers wide. This means that micro-EDM can offer an aspect ratio of 20 in combination with a god dimensional control.

  7. CMOS compatible fabrication of 3D photonic crystals by nanoimprint lithography

    NASA Astrophysics Data System (ADS)

    Eibelhuber, M.; Uhrmann, T.; Glinsner, T.

    2015-03-01

    Nanoimprinting techniques are an attractive solution for next generation lithography methods for several areas including photonic devices. A variety of potential applications have been demonstrated using nanoimprint lithography (NIL) (e.g. SAW devices, vias and contact layers with dual damascene imprinting process, Bragg structures, patterned media) [1,2]. Nanoimprint lithography is considered for bridging the gap from R and D to high volume manufacturing. In addition, it is capable to adapt to the needs of the fragmented and less standardized photonic market easily. In this work UV-NIL has been selected for the fabrication process of 3D-photonic crystals. It has been shown that UVNIL using a multiple layer approach is well suited to fabricate a 3D woodpile photonic crystal. The necessary alignment accuracies below 100nm were achieved using a simple optical method. In order to obtain sufficient alignment of the stacks to each other, a two stage alignment process is performed: at first proximity alignment is done followed by the Moiré alignment in soft contact with the substrate. Multiple steps of imprinting, etching, Si deposition and chemical mechanical polishing were implemented to create high quality 3D photonic crystals with up to 5 layers. This work has proven the applicability of nanoimprint lithography in a CMOS compatible process on 3D photonic crystals with alignment accuracy down to 100nm. Optimizing the processes will allow scaling up these structures on full wafers while still meeting the requirements of the designated devices.

  8. 3D printing method for freeform fabrication of optical phantoms simulating heterogeneous biological tissue

    NASA Astrophysics Data System (ADS)

    Wang, Minjie; Shen, Shuwei; Yang, Jie; Dong, Erbao; Xu, Ronald

    2014-03-01

    The performance of biomedical optical imaging devices heavily relies on appropriate calibration. However, many of existing calibration phantoms for biomedical optical devices are based on homogenous materials without considering the multi-layer heterogeneous structures observed in biological tissue. Using such a phantom for optical calibration may result in measurement bias. To overcome this problem, we propose a 3D printing method for freeform fabrication of tissue simulating phantoms with multilayer heterogeneous structure. The phantom simulates not only the morphologic characteristics of biological tissue but also absorption and scattering properties. The printing system is based on a 3D motion platform with coordinated control of the DC motors. A special jet nozzle is designed to mix base, scattering, and absorption materials at different ratios. 3D tissue structures are fabricated through layer-by-layer printing with selective deposition of phantom materials of different ingredients. Different mixed ratios of base, scattering and absorption materials have been tested in order to optimize the printing outcome. A spectrometer and a tissue spectrophotometer are used for characterizing phantom absorption and scattering properties. The goal of this project is to fabricate skin tissue simulating phantoms as a traceable standard for the calibration of biomedical optical spectral devices.

  9. Microelectro discharge machining: an innovative method for the fabrication of 3D microdevices

    NASA Astrophysics Data System (ADS)

    Lesche, Claudia; Krah, Thomas; Büttgenbach, Stephanus

    2011-06-01

    This paper reports on the potential of microelectro discharge machining (μEDM) as an innovative method for the fabrication of 3D microdevices. To demonstrate the wide capabilities of μEDM two different high-potential 3D microsystems - a microfluidic device for the dispersion of nanoparticles and a star probe for microcoordinate metrology - are presented. For the fabrication of these microdevices a μEDM-milling machine with integrated microwire electro discharge grinding (μWEDG) module is utilized. To gain optimized process conditions as well as a high surface quality an adequate adaption of the single erosion parameters such as energy, pulse frequency and spark gap has to be carried out and are discussed below. The dispersion micromodule is used for pharmaceutical screening applications in a high pressure range up to 2000 bar. At the channel bottom a surface roughness of Ra = 80 nm is achieved. In case of the star probe it is possible to produce shaft and sphere out of one piece. The fabricated stylus elements have sphere diameters of 40-200 μm. For both applications μEDM offers a flexible, precise, effective and cost-efficient fabrication method for the machining of hard and resistant materials.

  10. Design tools for microstructured optical fiber fabrication

    NASA Astrophysics Data System (ADS)

    Buchak, Peter; Crowdy, Darren; Stokes, Yvonne; Chen, Michael

    2015-11-01

    The advent of microstructured optical fibers (MOFs) has opened up possibilities for controlling light not available with conventional optical fiber. A MOF, which differs from a conventional fiber by having an array of air channels running along its length, is fabricated by heating and drawing a glass preform at low Reynolds number. However, because surface tension causes the cross section to deform, the geometry of the channels in the fiber differs from the preform. As a result, fabricating a desired fiber configuration may necessitate extensive trial and error. In this talk, we describe our work on fiber drawing, which has led to methods for predicting the fiber geometries that result at given draw conditions. More importantly, our methods can be used to obtain the preform configuration required to produce a fiber with a desired arrangement of channels. We have implemented our methods in software tools to facilitate preform design.

  11. Fabrication of three-dimensional and submicrometer-scaled microstructures based on metal contact printing and silicon bulk machining

    NASA Astrophysics Data System (ADS)

    Kao, Kuo-Lun; Chang, Cho-Wei; Lee, Yung-Chun

    2014-04-01

    This paper describes a method that contains a series of processes for producing three-dimensional (3-D) microstructures with a feature size in the submicrometer scale. It starts from using a metal contact printing lithography to pattern a thin metal film on the surface of a (100) silicon substrate. The metal film has a hole-array pattern with a hole diameter ranging from 300 nm to 800 nm and is used as an etching mask for silicon bulk machining to create concave pyramid-shaped surface microstructures. Using this bulk-machined silicon substrate as a template, polymer 3-D microstructures are replicated on top of a silicon dioxide (SiO) layer. Finally, through a dry etching process, 3-D microstructures with a profile similar to the replicated polymer microstructures are formed on the SiO layer. Potential applications of these fabricated SiO microstructures in the light-emitting diode industry will be addressed.

  12. Fabrication of controlled-release budesonide tablets via desktop (FDM) 3D printing.

    PubMed

    Goyanes, Alvaro; Chang, Hanah; Sedough, Daniel; Hatton, Grace B; Wang, Jie; Buanz, Asma; Gaisford, Simon; Basit, Abdul W

    2015-12-30

    The aim of this work was to explore the feasibility of using fused deposition modelling (FDM) 3D printing (3DP) technology with hot melt extrusion (HME) and fluid bed coating to fabricate modified-release budesonide dosage forms. Budesonide was sucessfully loaded into polyvinyl alcohol filaments using HME. The filaments were engineered into capsule-shaped tablets (caplets) containing 9mg budesonide using a FDM 3D printer; the caplets were then overcoated with a layer of enteric polymer. The final printed formulation was tested in a dynamic dissolution bicarbonate buffer system, and two commercial budesonide products, Cortiment® (Uceris®) and Entocort®, were also investigated for comparison. Budesonide release from the Entocort® formulation was rapid in conditions of the upper small intestine while release from the Cortiment® product was more delayed and very slow. In contrast, the new 3D printed caplet formulation started to release in the mid-small intestine but release then continued in a sustained manner throughout the distal intestine and colon. This work has demonstrated the potential of combining FDM 3DP with established pharmaceutical processes, including HME and film coating, to fabricate modified release oral dosage forms. PMID:26481468

  13. Chitosan-g-lactide copolymers for fabrication of 3D scaffolds for tissue engineering

    NASA Astrophysics Data System (ADS)

    Demina, T. S.; Zaytseva-Zotova, D. S.; Timashev, P. S.; Bagratashvili, V. N.; Bardakova, K. N.; Sevrin, Ch; Svidchenko, E. A.; Surin, N. M.; Markvicheva, E. A.; Grandfils, Ch; Akopova, T. A.

    2015-07-01

    Chitosan-g-oligo (L, D-lactide) copolymers were synthesized and assessed to fabricate a number of 3D scaffolds using a variety of technologies such as oil/water emulsion evaporation technique, freeze-drying and two-photon photopolymerization. Solid-state copolymerization method allowed us to graft up to 160 wt-% of oligolactide onto chitosan backbone via chitosan amino group acetylation with substitution degree reaching up to 0.41. Grafting of hydrophobic oligolactide side chains with polymerization degree up to 10 results in chitosan amphiphilic properties. The synthesized chitosan-g-lactide copolymers were used to design 3D scaffolds for tissue engineering such as spherical microparticles and macroporous hydrogels.

  14. Large-area fabrication of 3D petal-like nanopattern for surface enhanced Raman scattering

    NASA Astrophysics Data System (ADS)

    Zhou, Weimin; Wang, Jinhe; Zhang, Jing; Li, Xiaoli; Min, Guoquan

    2014-06-01

    A very easy and flexible approach to fabricate large area, petal-like nanopattern for surface enhanced Raman scattering using soft imprint lithography are presented here. The morphology of the petal-like nanopattern can be transferred truly using the h-PDMS and diluted PMMA molding template. By means of Au metal deposition, a SERS substrate with high enhancement factor over large area, which is still a problem, was produced easily. The morphology and Raman enhancement effect of the 3D nanopattern are characterized by SEM, AFM and SERS. The results show that the petal-like 3D nanopattern has high SERS enhancement factor (order of 1.0 × 108) and could be a promising low cost and high performance SERS active substrate.

  15. Injectable 3-D Fabrication of Medical Electronics at the Target Biological Tissues

    NASA Astrophysics Data System (ADS)

    Jin, Chao; Zhang, Jie; Li, Xiaokang; Yang, Xueyao; Li, Jingjing; Liu, Jing

    2013-12-01

    Conventional transplantable biomedical devices generally request sophisticated surgery which however often causes big trauma and serious pain to the patients. Here, we show an alternative way of directly making three-dimensional (3-D) medical electronics inside the biological body through sequential injections of biocompatible packaging material and liquid metal ink. As the most typical electronics, a variety of medical electrodes with different embedded structures were demonstrated to be easily formed at the target tissues. Conceptual in vitro experiments provide strong evidences for the excellent performances of the injectable electrodes. Further in vivo animal experiments disclosed that the formed electrode could serve as both highly efficient ECG (Electrocardiograph) electrode and stimulator electrode. These findings clarified the unique features and practicability of the liquid metal based injectable 3-D fabrication of medical electronics. The present strategy opens the way for directly manufacturing electrophysiological sensors or therapeutic devices in situ via a truly minimally invasive approach.

  16. Injectable 3-D Fabrication of Medical Electronics at the Target Biological Tissues

    PubMed Central

    Jin, Chao; Zhang, Jie; Li, Xiaokang; Yang, Xueyao; Li, Jingjing; Liu, Jing

    2013-01-01

    Conventional transplantable biomedical devices generally request sophisticated surgery which however often causes big trauma and serious pain to the patients. Here, we show an alternative way of directly making three-dimensional (3-D) medical electronics inside the biological body through sequential injections of biocompatible packaging material and liquid metal ink. As the most typical electronics, a variety of medical electrodes with different embedded structures were demonstrated to be easily formed at the target tissues. Conceptual in vitro experiments provide strong evidences for the excellent performances of the injectable electrodes. Further in vivo animal experiments disclosed that the formed electrode could serve as both highly efficient ECG (Electrocardiograph) electrode and stimulator electrode. These findings clarified the unique features and practicability of the liquid metal based injectable 3-D fabrication of medical electronics. The present strategy opens the way for directly manufacturing electrophysiological sensors or therapeutic devices in situ via a truly minimally invasive approach. PMID:24309385

  17. Design and fabrication of a freeform prism array for 3D microscopy.

    PubMed

    Li, Lei; Yi, Allen Y

    2010-12-01

    Traditional microscopes have limitations in obtaining true 3D (three-dimensional) stereovision. Although some optical microscopes have been developed for 3D vision, many of them are complex, expensive, or limited to transparent samples. In this research, a freeform optical prism array was designed and fabricated to achieve 3D stereo imaging capability for microscope and machine vision applications. To form clear stereo images from multiple directions simultaneously, freeform optical surface design was applied to the prisms. In a ray tracing operation to determine the optical performance of the freeform prisms, Taylor series was used to calculate the surface shape. The virtual image spot diagrams were generated by using ray tracing methods for both the freeform prisms and the regular prisms. The results showed that all the light rays can be traced back to a single point for the freeform prism, and aberration was much smaller than that of the regular prism. The ray spots formed by the freeform prisms were adequate for image formation. Furthermore, the freeform prism array was fabricated by using a combined ultraprecision diamond turning and slow tool servo broaching process in a single, uninterrupted operation. The slow tool servo process ensured that the relative tolerance among prisms is guaranteed by the precision of the ultraprecision machine without the need for assembly. Finally 3D imaging tests were conducted to verify the freeform prism array's optical performance. The principle of the freeform prism array investigated in this research can be applied to microscopy, machine vision, robotic sensing, and many other areas. PMID:21119746

  18. 3D chiral nanoplasmonics: fabrication, chiroptic engineering, mechanism, and application in enantioselection (Presentation Recording)

    NASA Astrophysics Data System (ADS)

    Huang, Zhifeng

    2015-09-01

    Chirality does naturally exist, and the building blocks of life (e.g. DNA, proteins, peptides and sugars) are usually chiral. Chirality inherently imposes chemical/biological selectivity on functional molecules; hence the discrimination in molecular chirality from an enantiomer to the other mirror image (i.e. enantioselection) has fundamental and application significance. Enantiomers interact with left and right handed circularly polarized light in a different manner with respect to optical extinction; hence, electronic circular dichroism (ECD) has been widely used for enantioselection. However, enantiomers usually have remarkably low ECD intensity, mainly owing to the small electric transition dipole moment induced by molecular sizes compared to the ECD-active wavelength in the UV-visible-near IR region. To enhance ECD magnitude, recently it has being developed 3D chiral nanoplasmonic structures having a helical path, and the dimensions are comparable to the ECD wavelength. However, it is still ambiguous the origin of 3D chiroplasmonics, and there is a lack of studying the interaction of 3D chiroplasmoncs with enantiomers for the application of enantioselection. Herein, we will present a one-step fabrication of 3D silver nanospirals (AgNSs) via low-substrate-temperature glancing angle deposition. AgNSs can be deposited on a wide range of substrates (including transparent and flexible substrates), in an area on the order of cm2. A set of spiral dimensions (such as spiral pitches, number of turns and handedness) have been easily engineered to tune the chiroptic properties, leading to studying the chiroplasmonic principles together with finite element simulation and the LC model. At the end, it will be demonstrated that 3D chiroplasmonics can differentiate molecular chirality of enantiomers with dramatic enhancement in the anisotropy g factor. This study opens a door to sensitively discriminate enantiomer chirality.

  19. Fabrication and Characterization of 3D Micro- and Nanoelectrodes for Neuron Recordings

    PubMed Central

    Dimaki, Maria; Vazquez, Patricia; Olsen, Mark Holm; Sasso, Luigi; Rodriguez-Trujillo, Romen; Vedarethinam, Indumathi; Svendsen, Winnie E.

    2010-01-01

    In this paper we discuss the fabrication and characterization of three dimensional (3D) micro- and nanoelectrodes with the goal of using them for extra- and intracellular studies. Two different types of electrodes will be described: high aspect ratio microelectrodes for studying the communication between cells and ultimately for brain slice recordings and small nanoelectrodes for highly localized measurements and ultimately for intracellular studies. Electrical and electrochemical characterization of these electrodes as well as the results of PC12 cell differentiation on chip will be presented and discussed. PMID:22163473

  20. Fabrication of 3D polymer photonic crystals for near-IR applications

    NASA Astrophysics Data System (ADS)

    Yao, Peng; Qiu, Liang; Shi, Shouyuan; Schneider, Garrett J.; Prather, Dennis W.; Sharkawy, Ahmed; Kelmelis, Eric

    2008-02-01

    Photonic crystals[1, 2] have stirred enormous research interest and became a growing enterprise in the last 15 years. Generally, PhCs consist of periodic structures that possess periodicity comparable with the wavelength that the PhCs are designed to modulate. If material and periodic pattern are properly selected, PhCs can be applied to many applications based on their unique properties, including photonic band gaps (PBG)[3], self-collimation[4], super prism[5], etc. Strictly speaking, PhCs need to possess periodicity in three dimensions to maximize their advantageous capabilities. However, many current research is based on scaled two-dimensional PhCs, mainly due to the difficulty of fabrication such three-dimensional PhCs. Many approaches have been explored for the fabrication of 3D photonic crystals, including layer-by-layer surface micromachining[6], glancing angle deposition[7], 3D micro-sculpture method[8], self-assembly[9] and lithographical methods[10-12]. Among them, lithographic methods became increasingly accepted due to low costs and precise control over the photonic crystal structure. There are three mostly developed lithographical methods, namely X-ray lithography[10], holographic lithography[11] and two-photon polymerization[12]. Although significant progress has been made in developing these lithography-based technologies, these approaches still suffer from significant disadvantages. X-ray lithography relies on an expensive radiation source. Holographic lithography lacks the flexibility to create engineered defects, and multi-photon polymerization is not suitable for parallel fabrication. In our previous work, we developed a multi-layer photolithography processes[13, 14] that is based on multiple resist application and enhanced absorption upon exposure. Using a negative lift-off resist (LOR) and 254nm DUV source, we have demonstrated fabrication of 3D arbitrary structures with feature size of several microns. However, severe intermixing problem

  1. Size-Controlled Fabrication of Polyaniline Microfibers Based on 3D Hydrodynamic Focusing Approach.

    PubMed

    Yoo, Imsung; Song, Simon; Uh, Kyungchan; Lee, Chan Woo; Kim, Jong-Man

    2015-07-01

    Owing to the relatively high conductivity and unique redox behavior, polyaniline (PANI) has been one of the most technologically promising conducting polymers. Although various methodologies have been developed, fabrication of PANI microfibers has been a challenging task owing to the poor solubility in most organic solvents. By taking advantage of a microfluidic technology and organic soluble acid labile t-Boc-protected PANI (t-Boc-PANI) as the conducting polymer precursor, fabrication of PANI microfibers in a size-controlled manner is possible. Introduction of a THF solution containing t-Boc-PANI, and dodecylbenzenesulfonic acid (DBSA) as a core flow, and water as a sheath flow into a microfluidic channel with a 3D hydrodynamic focusing effect results in crystallization of the polymer fiber. By changing the flow rate, linear PANI microfibers that range from 16.2 to 39.4 μm in diameter are readily obtained. PMID:25882095

  2. Optical 3D Nano-fabrication: Drawing or Growing? (Conference Presentation)

    NASA Astrophysics Data System (ADS)

    Kawata, Satoshi

    2016-05-01

    Conventional nanotechnology based on the lithography and scanning probe microscopy is limited to 2D fabrication and modification. Here, I will talk about the method for 3D laser fabrication with two-photon polymerization [1], two-photon isomerization [2], and two-photon photo-reduction [3]. Self-growth technology, such as self-grown fiber structures of polymer [4] and self-grown metallic fractal metamaterials structures [5] will be also discussed. [1] S. Kawata, et. al, Nature 412, 697-698, 2001. [2] S. Kawata and Y. Kawata, Chem Rev. 88, 083110, 2006. [3] Y. -Y. Cao, et. al., Small 5, 1144-1148, 2009 [4] S. Shoji and S. Kawata, Appl. Phys. Lett. 75, 737-739, 1999. [5] N. Takeyasu, N. Nishimura, S. Kawata, submitted.

  3. Mass fabrication and delivery of 3D multilayer μTags into living cells

    PubMed Central

    Chen, Lisa Y.; Parizi, Kokab B.; Kosuge, Hisanori; Milaninia, Kaveh M.; McConnell, Michael V.; Wong, H.-S. Philip; Poon, Ada S. Y.

    2013-01-01

    Continuous monitoring of in vivo biological processes and their evolution at the cellular level would enable major advances in our understanding of biology and disease. As a stepping stone towards chronic cellular monitoring, we demonstrate massively parallel fabrication and delivery of 3D multilayer micro-Tags (μTags) into living cells. Both 10 μm × 10 μm × 1.5 μm and 18 μm × 7 μm × 1.5 μm devices containing inductive and capacitive structures were designed and fabricated as potential passive radio-frequency identification tags. We show cellular internalization and persistence of μTags over a 5-day period. Our results represent a promising advance in technologies for studying biology and disease at the cellular level. PMID:23887586

  4. The Non-Newtonian Rheology of Real Magmas: insights into 3D microstructures

    NASA Astrophysics Data System (ADS)

    Pistone, M.; Caricchi, L.; Ulmer, P.; Reusser, E.; Marone, F.; Burlini, L.

    2010-12-01

    We present high-resolution 3D microstructures of three-phase magmas composed of melt, bubbles and crystals in different proportions deformed at magmatic pressure and temperature conditions. This study aims to constrain the dependence of rheological and physical properties of magmas on the viscosity of the silicate melt, the applied deformation rate, the relative contents of crystals and bubbles and on the interactions between these phases. The starting material is composed of a hydrous haplogranitic melt containing H2O (2.26 wt%) and CO2 (624 ppm) and different proportions of quartz crystals (between 24 and 65 vol%; 63-125 μm in diameter) and bubbles (between 9 and 12 vol%; 5-150 μm in diameter). Experiments were performed in simple shear using a HT-HP internally-heated Paterson-type rock deformation apparatus (Paterson and Olgaard, 2000) at strain rates ranging between 5×10-5 s-1 and 4×10-3 s-1, at a constant pressure of 200 MPa and temperatures ranging between 723 and 1023 K. Synchrotron based X-ray tomographic microscopy performed at the TOMCAT beamline (Stampanoni et al., 2006) at the Swiss Light Source enabled quantitative evaluation of the 3D microstructure. At high temperature and low strain rate conditions the silicate melt behaves as a Newtonian liquid (Webb and Dingwell, 1990). Higher deformation rates and the contemporary presence of gas bubbles and solid crystals make magma rheology more complex and non-Newtonian behaviour occurs. In all experimental runs two different non-Newtonian effects were observed: shear thinning (decrease of viscosity with increasing strain rate) in high crystal-content magmas (55-65 vol% crystals; 9-10 vol% bubbles) and shear thickening (increase of viscosity with increasing strain rate) in magmas at lower degree of crystallinity (24 vol% crystals; 12 vol% bubbles). Both behaviours were observed at intermediate crystal-content (44 vol% crystals; 12 vol% bubbles), with an initial thickening that subsequently gives way to

  5. Fabrication of 2D and 3D Constructs From Reconstituted Decellularized Tissue Extracellular Matrices

    PubMed Central

    Takeda, Yuji S; Xu, Qiaobing

    2016-01-01

    We demonstrated a novel process to reconstitute a decellularized extracellular matrix (Recon-ECM) of heart and liver tissue using a combination of mechanical homogenization and enzymatic digestion. Such Recon-ECM was used as a biomaterial to produce flat or micro-patterned 2D films after crosslinking using replica molding. The mechanical properties of the resulting films were tuned by changing the type of crosslinking reagents. We also demonstrated the fabrication of mechanically robust 3D scaffolds by freeze-drying of the Recon-ECM solution. The porosity of the 3D scaffold was controlled by changing the concentration of the Recon-ECM. HepG2 cells were used to investigate the potential substrate of these engineered 2D patterned and 3D porous structures. The cell attachment, proliferation, and urea synthesis were evaluated, and the results indicate that the scaffold generated from Recon-ECM provides a biologically friendly environment for cells to grow. This method provides a new way to use decellularized ECM as source of biomaterial to produce novel scaffold with better controlled micro- and nano-scale structures, tunable physicochemical properties with desired biological functions. PMID:26000376

  6. Simple and Versatile 3D Printed Microfluidics Using Fused Filament Fabrication

    PubMed Central

    Morgan, Alex J. L.; Hidalgo San Jose, Lorena; Jamieson, William D.; Wymant, Jennifer M.; Song, Bing; Stephens, Phil

    2016-01-01

    The uptake of microfluidics by the wider scientific community has been limited by the fabrication barrier created by the skills and equipment required for the production of traditional microfluidic devices. Here we present simple 3D printed microfluidic devices using an inexpensive and readily accessible printer with commercially available printer materials. We demonstrate that previously reported limitations of transparency and fidelity have been overcome, whilst devices capable of operating at pressures in excess of 2000 kPa illustrate that leakage issues have also been resolved. The utility of the 3D printed microfluidic devices is illustrated by encapsulating dental pulp stem cells within alginate droplets; cell viability assays show the vast majority of cells remain live, and device transparency is sufficient for single cell imaging. The accessibility of these devices is further enhanced through fabrication of integrated ports and by the introduction of a Lego®-like modular system facilitating rapid prototyping whilst offering the potential for novices to build microfluidic systems from a database of microfluidic components. PMID:27050661

  7. Fabrication of capacitive acoustic resonators combining 3D printing and 2D inkjet printing techniques.

    PubMed

    Haque, Rubaiyet Iftekharul; Ogam, Erick; Loussert, Christophe; Benaben, Patrick; Boddaert, Xavier

    2015-01-01

    A capacitive acoustic resonator developed by combining three-dimensional (3D) printing and two-dimensional (2D) printed electronics technique is described. During this work, a patterned bottom structure with rigid backplate and cavity is fabricated directly by a 3D printing method, and then a direct write inkjet printing technique has been employed to print a silver conductive layer. A novel approach has been used to fabricate a diaphragm for the acoustic sensor as well, where the conductive layer is inkjet-printed on a pre-stressed thin organic film. After assembly, the resulting structure contains an electrically conductive diaphragm positioned at a distance from a fixed bottom electrode separated by a spacer. Measurements confirm that the transducer acts as capacitor. The deflection of the diaphragm in response to the incident acoustic single was observed by a laser Doppler vibrometer and the corresponding change of capacitance has been calculated, which is then compared with the numerical result. Observation confirms that the device performs as a resonator and provides adequate sensitivity and selectivity at its resonance frequency. PMID:26473878

  8. Design and fabrication of a foldable 3D silicon based package for solid state lighting applications

    NASA Astrophysics Data System (ADS)

    Sokolovskij, R.; Liu, P.; van Zeijl, H. W.; Mimoun, B.; Zhang, G. Q.

    2015-05-01

    Miniaturization of solid state lighting (SSL) luminaires as well as reduction of packaging and assembly costs are of prime interest for the SSL lighting industry. A novel silicon based LED package for lighting applications is presented in this paper. The proposed design consists of 5 rigid Si tiles connected by flexible polyimide hinges with embedded interconnects (ICs). Electrical, optical and thermal characteristics were taken into consideration during design. The fabrication process involved polyimide (PI) application and patterning, aluminium interconnect integration in the flexible hinge, LED reflector cavity formation and metalization followed by through wafer DRIE etching for chip formation and release. A method to connect chip front to backside without TSVs was also integrated into the process. Post-fabrication wafer level assembly included LED mounting and wirebond, phosphor-based colour conversion and silicone encapsulation. The package formation was finalized by vacuum assisted wrapping around an assembly structure to form a 3D geometry, which is beneficial for omnidirectional lighting. Bending tests were performed on the flexible ICs and optical performance at different temperatures was evaluated. It is suggested that 3D packages can be expanded to platforms for miniaturized luminaire applications by combining monolithic silicon integration and system-in-package (SiP) technologies.

  9. Fabrication of solution processed 3D nanostructured CuInGaS₂ thin film solar cells.

    PubMed

    Chu, Van Ben; Cho, Jin Woo; Park, Se Jin; Hwang, Yun Jeong; Park, Hoo Keun; Do, Young Rag; Min, Byoung Koun

    2014-03-28

    In this study we demonstrate the fabrication of CuInGaS₂ (CIGS) thin film solar cells with a three-dimensional (3D) nanostructure based on indium tin oxide (ITO) nanorod films and precursor solutions (Cu, In and Ga nitrates in alcohol). To obtain solution processed 3D nanostructured CIGS thin film solar cells, two different precursor solutions were applied to complete gap filling in ITO nanorods and achieve the desirable absorber film thickness. Specifically, a coating of precursor solution without polymer binder material was first applied to fill the gap between ITO nanorods followed by deposition of the second precursor solution in the presence of a binder to generate an absorber film thickness of ∼1.3 μm. A solar cell device with a (Al, Ni)/AZO/i-ZnO/CdS/CIGS/ITO nanorod/glass structure was constructed using the CIGS film, and the highest power conversion efficiency was measured to be ∼6.3% at standard irradiation conditions, which was 22.5% higher than the planar type of CIGS solar cell on ITO substrate fabricated using the same precursor solutions. PMID:24569126

  10. Simple and Versatile 3D Printed Microfluidics Using Fused Filament Fabrication.

    PubMed

    Morgan, Alex J L; Hidalgo San Jose, Lorena; Jamieson, William D; Wymant, Jennifer M; Song, Bing; Stephens, Phil; Barrow, David A; Castell, Oliver K

    2016-01-01

    The uptake of microfluidics by the wider scientific community has been limited by the fabrication barrier created by the skills and equipment required for the production of traditional microfluidic devices. Here we present simple 3D printed microfluidic devices using an inexpensive and readily accessible printer with commercially available printer materials. We demonstrate that previously reported limitations of transparency and fidelity have been overcome, whilst devices capable of operating at pressures in excess of 2000 kPa illustrate that leakage issues have also been resolved. The utility of the 3D printed microfluidic devices is illustrated by encapsulating dental pulp stem cells within alginate droplets; cell viability assays show the vast majority of cells remain live, and device transparency is sufficient for single cell imaging. The accessibility of these devices is further enhanced through fabrication of integrated ports and by the introduction of a Lego®-like modular system facilitating rapid prototyping whilst offering the potential for novices to build microfluidic systems from a database of microfluidic components. PMID:27050661

  11. Fabrication of Capacitive Acoustic Resonators Combining 3D Printing and 2D Inkjet Printing Techniques

    PubMed Central

    Haque, Rubaiyet Iftekharul; Ogam, Erick; Loussert, Christophe; Benaben, Patrick; Boddaert, Xavier

    2015-01-01

    A capacitive acoustic resonator developed by combining three-dimensional (3D) printing and two-dimensional (2D) printed electronics technique is described. During this work, a patterned bottom structure with rigid backplate and cavity is fabricated directly by a 3D printing method, and then a direct write inkjet printing technique has been employed to print a silver conductive layer. A novel approach has been used to fabricate a diaphragm for the acoustic sensor as well, where the conductive layer is inkjet-printed on a pre-stressed thin organic film. After assembly, the resulting structure contains an electrically conductive diaphragm positioned at a distance from a fixed bottom electrode separated by a spacer. Measurements confirm that the transducer acts as capacitor. The deflection of the diaphragm in response to the incident acoustic single was observed by a laser Doppler vibrometer and the corresponding change of capacitance has been calculated, which is then compared with the numerical result. Observation confirms that the device performs as a resonator and provides adequate sensitivity and selectivity at its resonance frequency. PMID:26473878

  12. Scalable shape-controlled fabrication of curved microstructures using a femtosecond laser wet-etching process.

    PubMed

    Bian, Hao; Yang, Qing; Chen, Feng; Liu, Hewei; Du, Guangqing; Deng, Zefang; Si, Jinhai; Yun, Feng; Hou, Xun

    2013-07-01

    Materials with curvilinear surface microstructures are highly desirable for micro-optical and biomedical devices. However, realization of such devices efficiently remains technically challenging. This paper demonstrates a facile and flexible method to fabricate curvilinear microstructures with controllable shapes and dimensions. The method composes of femtosecond laser exposures and chemical etching process with the hydrofluoric acid solutions. By fixed-point and step-in laser irradiations followed by the chemical treatments, concave microstructures with different profiles such as spherical, conical, bell-like and parabola were fabricated on silica glasses. The convex structures were replicated on polymers by the casting replication process. In this work, we used this technique to fabricate high-quality microlens arrays and high-aspect-ratio microwells which can be used in 3D cell culture. This approach offers several advantages such as high-efficient, scalable shape-controllable and easy manipulations. PMID:23623098

  13. Microstructures fabricated by dynamically controlled femtosecond patterned vector optical fields.

    PubMed

    Cai, Meng-Qiang; Li, Ping-Ping; Feng, Dan; Pan, Yue; Qian, Sheng-Xia; Li, Yongnan; Tu, Chenghou; Wang, Hui-Tian

    2016-04-01

    We have presented and demonstrated a method for the fabrication of various complicated microstructures based on dynamically controlled patterned vector optical fields (PVOFs). We design and generate dynamic PVOFs by loading patterned holograms displayed on the spatial light modulator and moving traces of focuses with different patterns. We experimentally fabricate the various microstructures in z-cut lithium niobate plates. The method we present has some benefits such as no motion of the fabricated samples and high efficiency due to its parallel feature. Moreover, our approach is able to fabricate three-dimensional microstructures. PMID:27192265

  14. Increased sensitivity of 3D-Well enzyme-linked immunosorbent assay (ELISA) for infectious disease detection using 3D-printing fabrication technology.

    PubMed

    Singh, Harpal; Shimojima, Masayuki; Fukushi, Shuetsu; Le Van, An; Sugamata, Masami; Yang, Ming

    2015-01-01

    Enzyme-linked Immunosorbent Assay or ELISA -based diagnostics are considered the gold standard in the demonstration of various immunological reaction including in the measurement of antibody response to infectious diseases and to support pathogen identification with application potential in infectious disease outbreaks and individual patients' treatment and clinical care. The rapid prototyping of ELISA-based diagnostics using available 3D printing technologies provides an opportunity for a further exploration of this platform into immunodetection systems. In this study, a '3D-Well' was designed and fabricated using available 3D printing platforms to have an increased surface area of more than 4 times for protein-surface adsorption compared to those of 96-well plates. The ease and rapidity in designing-product development-feedback cycle offered through 3D printing platforms provided an opportunity for its rapid assessment, in which a chemical etching process was used to make the surface hydrophilic followed by validation through the diagnostic performance of ELISA for infectious disease without modifying current laboratory practices for ELISA. The higher sensitivity of the 3D-Well (3-folds higher) compared to the 96-well ELISA provides a potential for the expansion of this technology towards miniaturization platforms to reduce time, volume of reagents and samples needed for laboratory or field diagnosis of infectious diseases including applications in other disciplines. PMID:26406036

  15. Creeping proteins in microporous structures: polymer brush-assisted fabrication of 3D gradients for tissue engineering.

    PubMed

    Gunnewiek, Michel Klein; Di Luca, Andrea; Bollemaat, Hermannes Z; van Blitterswijk, Clemens A; Vancso, G Julius; Moroni, Lorenzo; Benetti, Edmondo M

    2015-06-01

    Coupling of rapid prototyping techniques and surface-confined polymerizations allows the fabrication of 3D multidirectional gradients of biomolecules within microporous scaffolds. The compositional gradients can be tailored by polymer-brush-assisted diffusion of protein solutions. This technique allows spatial control over stem cells manipulation within 3D environments. PMID:25676461

  16. Preclinical study of SZ2080 material 3D microstructured scaffolds for cartilage tissue engineering made by femtosecond direct laser writing lithography.

    PubMed

    Mačiulaitis, Justinas; Deveikytė, Milda; Rekštytė, Sima; Bratchikov, Maksim; Darinskas, Adas; Šimbelytė, Agnė; Daunoras, Gintaras; Laurinavičienė, Aida; Laurinavičius, Arvydas; Gudas, Rimtautas; Malinauskas, Mangirdas; Mačiulaitis, Romaldas

    2015-01-01

    Over the last decade DLW employing ultrafast pulsed lasers has become a well-established technique for the creation of custom-made free-form three-dimensional (3D) microscaffolds out of a variety of materials ranging from proteins to biocompatible glasses. Its potential applications for manufacturing a patient's specific scaffold seem unlimited in terms of spatial resolution and geometry complexity. However, despite few exceptions in which live cells or primitive organisms were encapsulated into a polymer matrix, no demonstration of an in vivo study case of scaffolds generated with the use of such a method was performed. Here, we report a preclinical study of 3D artificial microstructured scaffolds out of hybrid organic-inorganic (HOI) material SZ2080 fabricated using the DLW technique. The created 2.1 × 2.1 × 0.21 mm(3) membrane constructs are tested both in vitro by growing isolated allogeneic rabbit chondrocytes (Cho) and in vivo by implanting them into rabbit organisms for one, three and six months. An ex vivo histological examination shows that certain pore geometry and the pre-growing of Cho prior to implantation significantly improves the performance of the created 3D scaffolds. The achieved biocompatibility is comparable to the commercially available collagen membranes. The successful outcome of this study supports the idea that hexagonal-pore-shaped HOI microstructured scaffolds in combination with Cho seeding may be successfully implemented for cartilage tissue engineering. PMID:25797444

  17. Surface 3D Micro Free Forms: Multifunctional Microstructured Mesoporous α-Alumina by in Situ Slip Casting Using Excimer Laser Ablated Polycarbonate Molds.

    PubMed

    Rowthu, Sriharitha; Böhlen, Karl; Bowen, Paul; Hoffmann, Patrik

    2015-11-11

    Ceramic surface microstructuring is a rapidly growing field with a variety of applications in tribology, wetting, biology, and so on. However, there are limitations to large-area microstructuring and fabrication of three-dimensional (3D) micro free forms. Here, we present a route to obtain intricate surface structures through in situ slip casting using polydimethylsiloxane (PDMS) negative molds which are replicated from excimer laser ablated polycarbonate (PC) master molds. PC sheets are ablated with a nanosecond KrF (λ = 248 nm) excimer laser mask projection system to obtain micron-scale 3D surface features over a large area of up to 3 m(2). Complex surface structures that include 3D free forms such as 3D topography of Switzerland, shallow structures such as diffractive optical elements (60 nm step) and conical micropillars have been obtained. The samples are defect-free produced with thicknesses of up to 10 mm and 120 mm diameter. The drying process of the slip cast alumina slurry takes place as a one-dimensional process, through surface evaporation and water permeation through the PDMS membrane. This allows homogeneous one-dimensional shrinkage during the drying process, independent of the sample's lateral dimensions. A linear mass diffusion model has been proposed to predict and explain the drying process of these ceramic colloidal suspensions. The calculated drying time is linearly proportional to the height of the slurry and the thickness of the negatively structured PDMS and is validated by the experimental results. An experimentally observed optimum Sylgard PDMS thickness range of ∼400 μm to 1 mm has achieved the best quality microstructured green compacts. Further, the model predicts that the drying time is independent of the microstructured areas and was validated using experimental observations carried out with microstructured areas of 300 mm(2), 1200 mm(2), and 120 cm(2). Therefore, in principle, the structures can be further replicated in areas up

  18. Fabrication of digital rainbow holograms and 3-D imaging using SEM based e-beam lithography.

    PubMed

    Firsov, An; Firsov, A; Loechel, B; Erko, A; Svintsov, A; Zaitsev, S

    2014-11-17

    Here we present an approach for creating full-color digital rainbow holograms based on mixing three basic colors. Much like in a color TV with three luminescent points per single screen pixel, each color pixel of initial image is presented by three (R, G, B) distinct diffractive gratings in a hologram structure. Change of either duty cycle or area of the gratings are used to provide proper R, G, B intensities. Special algorithms allow one to design rather complicated 3D images (that might even be replacing each other with hologram rotation). The software developed ("RainBow") provides stability of colorization of rotated image by means of equalizing of angular blur from gratings responsible for R, G, B basic colors. The approach based on R, G, B color synthesis allows one to fabricate gray-tone rainbow hologram containing white color what is hardly possible in traditional dot-matrix technology. Budgetary electron beam lithography based on SEM column was used to fabricate practical examples of digital rainbow hologram. The results of fabrication of large rainbow holograms from design to imprinting are presented. Advantages of the EBL in comparison to traditional optical (dot-matrix) technology is considered. PMID:25402115

  19. Elasto-Capillary Folding Using Stop-Programmable Hinges Fabricated by 3D Micro-Machining

    PubMed Central

    Legrain, Antoine; Berenschot, Erwin J. W.; Tas, Niels R.; Abelmann, Leon

    2015-01-01

    We show elasto-capillary folding of silicon nitride objects with accurate folding angles between flaps of (70.6 ± 0.1)° and demonstrate the feasibility of such accurate micro-assembly with a final folding angle of 90°. The folding angle is defined by stop-programmable hinges that are fabricated starting from silicon molds employing accurate three-dimensional corner lithography. This nano-patterning method exploits the conformal deposition and the subsequent timed isotropic etching of a thin film in a 3D shaped silicon template. The technique leaves a residue of the thin film in sharp concave corners which can be used as an inversion mask in subsequent steps. Hinges designed to stop the folding at 70.6° were fabricated batchwise by machining the V-grooves obtained by KOH etching in (110) silicon wafers; 90° stop-programmable hinges were obtained starting from silicon molds obtained by dry etching on (100) wafers. The presented technique has potential to achieve any folding angle and opens a new route towards creating structures with increased complexity, which will ultimately lead to a novel method for device fabrication. PMID:25992886

  20. A Novel Bio-carrier Fabricated Using 3D Printing Technique for Wastewater Treatment

    PubMed Central

    Dong, Yang; Fan, Shu-Qian; Shen, Yu; Yang, Ji-Xiang; Yan, Peng; Chen, You-Peng; Li, Jing; Guo, Jin-Song; Duan, Xuan-Ming; Fang, Fang; Liu, Shao-Yang

    2015-01-01

    The structure of bio-carriers is one of the key operational characteristics of a biofilm reactor. The goal of this study is to develop a series of novel fullerene-type bio-carriers using the three-dimensional printing (3DP) technique. 3DP can fabricate bio-carriers with more specialized structures compared with traditional fabrication processes. In this research, three types of fullerene-type bio-carriers were fabricated using the 3DP technique and then compared with bio-carrier K3 (from AnoxKaldnes) in the areas of physicochemical properties and biofilm growth. Images acquired by 3D profiling and SEM indicated that the surface roughness of the 3DP bio-carrier was greater than that of K3. Furthermore, contact angle data indicated that the 3DP bio-carriers were more hydrophilic than K3. The biofilm on the 3DP bio-carriers exhibited higher microbial activity and stronger adhesion ability. These findings were attributed to excellent mass transfer of the substrate (and oxygen) between the vapour-liquid-solid tri-phase system and to the surface characteristics. It is concluded that the novel 3DP fullerene-type bio-carriers are ideal carriers for biofilm adherence and growth. PMID:26202477

  1. A Novel Bio-carrier Fabricated Using 3D Printing Technique for Wastewater Treatment.

    PubMed

    Dong, Yang; Fan, Shu-Qian; Shen, Yu; Yang, Ji-Xiang; Yan, Peng; Chen, You-Peng; Li, Jing; Guo, Jin-Song; Duan, Xuan-Ming; Fang, Fang; Liu, Shao-Yang

    2015-01-01

    The structure of bio-carriers is one of the key operational characteristics of a biofilm reactor. The goal of this study is to develop a series of novel fullerene-type bio-carriers using the three-dimensional printing (3DP) technique. 3DP can fabricate bio-carriers with more specialized structures compared with traditional fabrication processes. In this research, three types of fullerene-type bio-carriers were fabricated using the 3DP technique and then compared with bio-carrier K3 (from AnoxKaldnes) in the areas of physicochemical properties and biofilm growth. Images acquired by 3D profiling and SEM indicated that the surface roughness of the 3DP bio-carrier was greater than that of K3. Furthermore, contact angle data indicated that the 3DP bio-carriers were more hydrophilic than K3. The biofilm on the 3DP bio-carriers exhibited higher microbial activity and stronger adhesion ability. These findings were attributed to excellent mass transfer of the substrate (and oxygen) between the vapour-liquid-solid tri-phase system and to the surface characteristics. It is concluded that the novel 3DP fullerene-type bio-carriers are ideal carriers for biofilm adherence and growth. PMID:26202477

  2. Design, analysis, and characterization of stress-engineered 3D microstructures comprised of PECVD silicon oxide and nitride

    NASA Astrophysics Data System (ADS)

    Pi, Chia-Hsing; Turner, Kevin T.

    2016-06-01

    Microelectromechanical systems (MEMS) are typically 2D or quasi-3D structures fabricated using surface and bulk micromachining processes. In this work, an approach for 3D structure fabrication based on stress engineering is demonstrated. Specifically, sub-mm 3D spherical cage-like structures are realized through the deformation of bilayers of residually-stressed silicon oxide and silicon nitride with micrometer-scale thicknesses. Analytical and finite models to predict the shape of stress-engineered structures based on geometry and residual stress are described and used for structure design. A systematic experimental study was performed to quantify residual stresses in silicon nitride films made by plasma-enhanced chemical vapor deposition (PECVD). The measurements show that the residual stress of PECVD silicon nitride can be tuned over a wide range of tensile stresses through the control of deposition parameters, such as flow rate and power. Stress engineered 3D cage-like structures comprised of PECVD silicon nitride and oxide films were fabricated. 3D structures with a range of curvatures were demonstrated. The measured geometry of the fabricated structures are in good agreement with predictions from analytical and finite element models.

  3. A simple configuration for fabrication of 2D and 3D photonic quasicrystals with complex structures

    NASA Astrophysics Data System (ADS)

    Sun, XiaoHong; Wang, Shuai; Liu, Wei; Jiang, LiuDi

    2016-06-01

    A simple method using a single-prism common-path interferometer is presented for the fabrication of complex quasicrystals in sub-micrometer scales. Multiple types of two-dimensional (2D) and three-dimensional (3D) quasicrystalline structures are designed and their diffraction patterns are obtained by using Fourier Transform method. Multi-fold rotational symmetries are demonstrated and compared. By using this method, a wide range of quasicrystals types can be produced with arbitrary complexities and rotational symmetries. The transmittance studies of 12-fold and 18-fold structures also reveal the existence of complete photonic bandgaps, which also demonstrates increased symmetry and significantly improved characteristics of photonic band-gaps.

  4. Developing on-machine 3D profile measurement for deterministic fabrication of aspheric mirrors.

    PubMed

    Dong, Zhichao; Cheng, Haobo; Ye, Xu; Tam, Hon-Yuen

    2014-08-01

    Three-dimensional profile measurement is perceived as an indispensable process for deterministic fabrication of aspheric mirrors. In this work, we develop on-machine 3D profile measurement on a subaperture polishing machine, namely, JR-1800. The influences of mechanical errors, misalignments, output stability, temperature variation, and natural vibration are investigated in detail by calibration, mechanical alignment, and finite-element analysis. Two quantitative methods are presented for aligning the turntable, length gauge, and workpiece into together. An error compensation model is also developed for further eliminating misalignments. For feasibility validation, two prototypical workpieces are measured by JR-1800 and an interferometer. The results indicate that JR-1800 has an RMS repeatability of ~λ/30 (λ=632.8  nm). The data provided by the two systems are highly coincident. Direct subtractions of the results from the two systems indicate that the RMS deviations for both segments are less than 0.07 μm. PMID:25090332

  5. Aerosol based direct-write micro-additive fabrication method for sub-mm 3D metal-dielectric structures

    NASA Astrophysics Data System (ADS)

    Rahman, Taibur; Renaud, Luke; Heo, Deuk; Renn, Michael; Panat, Rahul

    2015-10-01

    The fabrication of 3D metal-dielectric structures at sub-mm length scale is highly important in order to realize low-loss passives and GHz wavelength antennas with applications in wearable and Internet-of-Things (IoT) devices. The inherent 2D nature of lithographic processes severely limits the available manufacturing routes to fabricate 3D structures. Further, the lithographic processes are subtractive and require the use of environmentally harmful chemicals. In this letter, we demonstrate an additive manufacturing method to fabricate 3D metal-dielectric structures at sub-mm length scale. A UV curable dielectric is dispensed from an Aerosol Jet system at 10-100 µm length scale and instantaneously cured to build complex 3D shapes at a length scale  <1 mm. A metal nanoparticle ink is then dispensed over the 3D dielectric using a combination of jetting action and tilted dispense head, also using the Aerosol Jet technique and at a length scale 10-100 µm, followed by the nanoparticle sintering. Simulation studies are carried out to demonstrate the feasibility of using such structures as mm-wave antennas. The manufacturing method described in this letter opens up the possibility of fabricating an entirely new class of custom-shaped 3D structures at a sub-mm length scale with potential applications in 3D antennas and passives.

  6. Bioactive fish collagen/polycaprolactone composite nanofibrous scaffolds fabricated by electrospinning for 3D cell culture.

    PubMed

    Choi, Da Jeong; Choi, Seung Mi; Kang, Hae Yeong; Min, Hye-Jin; Lee, Rira; Ikram, Muhammad; Subhan, Fazli; Jin, Song Wan; Jeong, Young Hun; Kwak, Jong-Young; Yoon, Sik

    2015-07-10

    One of the most challenging objectives of 3D cell culture is the development of scaffolding materials with outstanding biocompatibility and favorable mechanical strength. In this study, we fabricated a novel nanofibrous scaffold composed of fish collagen (FC) and polycaprolactone (PCL) blends by using the electrospinning method. Nanofibrous scaffolds were characterized using a scanning electron microscope (SEM), and it was revealed that the diameter of nanofibers decreased as FC content was increased in the FC/PCL composite nanofibers. The cytocompatibility of the FC/PCL scaffolds was evaluated by SEM, WST-1 assay, confocal microscopy, western blot, and RT-PCR. It was found that the scaffolds not only facilitated the adhesion, spreading, protrusions, and proliferation of thymic epithelial cells (TECs), but also stimulated the expression of genes and proteins involved in cell adhesion and T-cell development. Thus, these results suggest that the FC/PCL composite nanofibrous scaffolds will be a useful model of 3D cell culture for TECs and may have wide applicability in the future for engineering tissues or organs. PMID:25617682

  7. Bottom-up Fabrication of Multilayer Stacks of 3D Photonic Crystals from Titanium Dioxide.

    PubMed

    Kubrin, Roman; Pasquarelli, Robert M; Waleczek, Martin; Lee, Hooi Sing; Zierold, Robert; do Rosário, Jefferson J; Dyachenko, Pavel N; Montero Moreno, Josep M; Petrov, Alexander Yu; Janssen, Rolf; Eich, Manfred; Nielsch, Kornelius; Schneider, Gerold A

    2016-04-27

    A strategy for stacking multiple ceramic 3D photonic crystals is developed. Periodically structured porous films are produced by vertical convective self-assembly of polystyrene (PS) microspheres. After infiltration of the opaline templates by atomic layer deposition (ALD) of titania and thermal decomposition of the polystyrene matrix, a ceramic 3D photonic crystal is formed. Further layers with different sizes of pores are deposited subsequently by repetition of the process. The influence of process parameters on morphology and photonic properties of double and triple stacks is systematically studied. Prolonged contact of amorphous titania films with warm water during self-assembly of the successive templates is found to result in exaggerated roughness of the surfaces re-exposed to ALD. Random scattering on rough internal surfaces disrupts ballistic transport of incident photons into deeper layers of the multistacks. Substantially smoother interfaces are obtained by calcination of the structure after each infiltration, which converts amorphous titania into the crystalline anatase before resuming the ALD infiltration. High quality triple stacks consisting of anatase inverse opals with different pore sizes are demonstrated for the first time. The elaborated fabrication method shows promise for various applications demanding broadband dielectric reflectors or titania photonic crystals with a long mean free path of photons. PMID:27045887

  8. Fabrication of 3-D Reconstituted Organoid Arrays by DNA-Programmed Assembly of Cells (DPAC).

    PubMed

    Todhunter, Michael E; Weber, Robert J; Farlow, Justin; Jee, Noel Y; Cerchiari, Alec E; Gartner, Zev J

    2016-01-01

    Tissues are the organizational units of function in metazoan organisms. Tissues comprise an assortment of cellular building blocks, soluble factors, and extracellular matrix (ECM) composed into specific three-dimensional (3-D) structures. The capacity to reconstitute tissues in vitro with the structural complexity observed in vivo is key to understanding processes such as morphogenesis, homeostasis, and disease. In this article, we describe DNA-programmed assembly of cells (DPAC), a method to fabricate viable, functional arrays of organoid-like tissues within 3-D ECM gels. In DPAC, dissociated cells are chemically functionalized with degradable oligonucleotide "Velcro," allowing rapid, specific, and reversible cell adhesion to a two-dimensional (2-D) template patterned with complementary DNA. An iterative assembly process builds up organoids, layer-by-layer, from this initial 2-D template and into the third dimension. Cleavage of the DNA releases the completed array of tissues that are captured and fully embedded in ECM gels for culture and observation. DPAC controls the size, shape, composition, and spatial heterogeneity of organoids and permits positioning of constituent cells with single-cell resolution even within cultures several centimeters long. © 2016 by John Wiley & Sons, Inc. PMID:27622567

  9. In-vivo behavior of Si-hydroxyapatite/polycaprolactone/DMB scaffolds fabricated by 3D printing.

    PubMed

    Meseguer-Olmo, Luis; Vicente-Ortega, Vicente; Alcaraz-Baños, Miguel; Calvo-Guirado, José Luis; Vallet-Regí, María; Arcos, Daniel; Baeza, Alejandro

    2013-07-01

    Scaffolds made of polycaprolactone and nanocrystalline silicon-substituted hydroxyapatite have been fabricated by 3D printing rapid prototyping technique. To asses that the scaffolds fulfill the requirements to be considered for bone grafting applications, they were implanted in New Zealand rabbits. Histological and radiological studies have demonstrated that the scaffolds implanted in bone exhibited an excellent osteointegration without the interposition of fibrous tissue between bone and implants and without immune response after 4 months of implantation. In addition, we have evaluated the possibility of improving the scaffolds efficiency by incorporating demineralized bone matrix during the preparation by 3D printing. When demineralized bone matrix (DBM) is incorporated, the efficacy of the scaffolds is enhanced, as new bone formation occurs not only in the peripheral portions of the scaffolds but also within its pores after 4 months of implantation. This enhanced performance can be explained in terms of the osteoinductive properties of the DBM in the scaffolds, which have been assessed through the new bone tissue formation when the scaffolds are ectopically implanted. PMID:23255259

  10. Supersoft lithography: candy-based fabrication of soft silicone microstructures.

    PubMed

    Moraes, Christopher; Labuz, Joseph M; Shao, Yue; Fu, Jianping; Takayama, Shuichi

    2015-01-01

    We designed a fabrication technique able to replicate microstructures in soft silicone materials (E < 1 kPa). Sugar-based 'hard candy' recipes from the confectionery industry were modified to be compatible with silicone processing conditions, and used as templates for replica molding. Microstructures fabricated in soft silicones can then be easily released by dissolving the template in water. We anticipate that this technique will be of particular importance in replicating physiologically soft, microstructured environments for cell culture, and demonstrate a first application in which intrinsically soft microstructures are used to measure forces generated by fibroblast-laden contractile tissues. PMID:26245893

  11. On Boundary Misorientation Distribution Functions and How to Incorporate them into 3D Models of Microstructural Evolution

    SciTech Connect

    Godfrey, A.W.; Holm, E.A.; Hughes, D.A.; Miodownik, M.

    1998-12-23

    The fundamental difficulties incorporating experimentally obtained-boundary disorientation distributions (BMD) into 3D microstructural models are discussed. An algorithm is described which overcomes these difficulties. The boundary misorientations are treated as a statistical ensemble which is evolved toward the desired BMD using a Monte Carlo method. The application of this algorithm to a number complex arbitrary BMDs shows that the approach is effective for both conserved and non-conserved textures. The algorithm is successfully used to create the BMDs observed in deformation microstructure containing both incidental dislocation boundaries (IDBs) and geometrically necessary boundaries (GNBs).

  12. 3D printed electromagnetic transmission and electronic structures fabricated on a single platform using advanced process integration techniques

    NASA Astrophysics Data System (ADS)

    Deffenbaugh, Paul Issac

    3D printing has garnered immense attention from many fields including in-office rapid prototyping of mechanical parts, outer-space satellite replication, garage functional firearm manufacture, and NASA rocket engine component fabrication. 3D printing allows increased design flexibility in the fabrication of electronics, microwave circuits and wireless antennas and has reached a level of maturity which allows functional parts to be printed. Much more work is necessary in order to perfect the processes of 3D printed electronics especially in the area of automation. Chapter 1 shows several finished prototypes of 3D printed electronics as well as newly developed techniques in fabrication. Little is known about the RF and microwave properties and applications of the standard materials which have been developed for 3D printing. Measurement of a wide variety of materials over a broad spectrum of frequencies up to 10 GHz using a variety of well-established measurement methods is performed throughout chapter 2. Several types of high frequency RF transmission lines are fabricated and valuable model-matched data is gathered and provided in chapter 3 for future designers' use. Of particular note is a fully 3D printed stripline which was automatically fabricated in one process on one machine. Some core advantages of 3D printing RF/microwave components include rapid manufacturing of complex, dimensionally sensitive circuits (such as antennas and filters which are often iteratively tuned) and the ability to create new devices that cannot be made using standard fabrication techniques. Chapter 4 describes an exemplary fully 3D printed curved inverted-F antenna.

  13. Fabrication and characterization of nanoclay modified PMR type polyimide composites reinforced with 3D woven basalt fabric

    NASA Astrophysics Data System (ADS)

    Xie, Jianfei; Qiu, Yiping

    2009-07-01

    Nanoclay modified PMR type polyimide composites were prepared from 3D orthogonal woven basalt fiber performs and nanoclay modified polyimide matrix resin, which derived from methylene dianiline (MDA), dimethyl ester of 3,3',4,4'- oxydiphthalic acid (ODPE), monomethyl ester of cis-5-norbornene-endo-2,3-dicarboxylic acid (NE) and nanoclay. The Na+-montmorillonite was organically treated using a 1:1 molar ratio mixture of dodecylamine (C12) and MDA. The rheological properties of neat B-stage PMR polyimide and 2% clay modified B-stage PMR polyimide were investigated. Based on the results obtained from the rheological tests, a two step compression molding process can be established for the composites. In the first step, the 3D fabric preforms were impregnated with polyimide resin in a vacuum oven and heated up for degassing the volatiles and by-products. In the second step, composites were compressed. The internal structure of the composites was observed by a microscope. Incorporation of 2% clay showed an improvement in the Tg and stiffness of the PMR polyimide. The resulting composites exhibited high thermal stability and good mechanical properties.

  14. Femtosecond laser 3D fabrication of whispering-gallery-mode microcavities

    NASA Astrophysics Data System (ADS)

    Xu, HuaiLiang; Sun, HongBo

    2015-11-01

    Whispering-gallery-mode (WGM) microcavities with high-quality factors and small volumes have attracted intense interests in the past decades because of their potential applications in various research fields such as quantum information, sensing, and optoelectronics. This leads to rapid advance in a variety of processing technologies that can create high-quality WGM micro- cavities. Due to the unique characteristics of femtosecond laser pulses with high peak intensity and ultrashort pulse duration, femtosecond laser shows the ability to carry out ultrahigh precision micromachining of a variety of transparent materials through nonlinear multiphoton absorption and tunneling ionization. This review paper describes the basic principle of femtosecond laser direct writing, and presents an overview of recent progress concerning femtosecond laser three-dimensional (3D) fabrications of optical WGM microcavities, which include the advances in the fabrications of passive and active WGMs microcavities in a variety of materials such as polymer, glass and crystals, as well as in processing the integrated WGM-microcavity device. Lastly, a summary of this dynamic field with a future perspective is given.

  15. Fabrication of scalable and structured tissue engineering scaffolds using water dissolvable sacrificial 3D printed moulds.

    PubMed

    Mohanty, Soumyaranjan; Larsen, Layla Bashir; Trifol, Jon; Szabo, Peter; Burri, Harsha Vardhan Reddy; Canali, Chiara; Dufva, Marin; Emnéus, Jenny; Wolff, Anders

    2015-10-01

    One of the major challenges in producing large scale engineered tissue is the lack of ability to create large highly perfused scaffolds in which cells can grow at a high cell density and viability. Here, we explore 3D printed polyvinyl alcohol (PVA) as a sacrificial mould in a polymer casting process. The PVA mould network defines the channels and is dissolved after curing the polymer casted around it. The printing parameters determined the PVA filament density in the sacrificial structure and this density resulted in different stiffness of the corresponding elastomer replica. It was possible to achieve 80% porosity corresponding to about 150 cm(2)/cm(3) surface to volume ratio. The process is easily scalable as demonstrated by fabricating a 75 cm(3) scaffold with about 16,000 interconnected channels (about 1m(2) surface area) and with a channel to channel distance of only 78 μm. To our knowledge this is the largest scaffold ever to be produced with such small feature sizes and with so many structured channels. The fabricated scaffolds were applied for in-vitro culturing of hepatocytes over a 12-day culture period. Smaller scaffolds (6×4 mm) were tested for cell culturing and could support homogeneous cell growth throughout the scaffold. Presumably, the diffusion of oxygen and nutrient throughout the channel network is rapid enough to support cell growth. In conclusion, the described process is scalable, compatible with cell culture, rapid, and inexpensive. PMID:26117791

  16. 3D ordered nanostructures fabricated by nanosphere lithography using an organometallic etch mask

    NASA Astrophysics Data System (ADS)

    Ling, Xing Yi; Acikgoz, Canet; Phang, In Yee; Hempenius, Mark A.; Reinhoudt, David N.; Vancso, G. Julius; Huskens, Jurriaan

    2010-08-01

    A new approach for fabricating porous structures on silicon substrates and on polymer surfaces, using colloidal particle arrays with a polymer mask of a highly etch-resistant organometallic polymer, is demonstrated. Monolayers of silica particles, with diameters of 60 nm, 150 nm, 300 nm, or 500 nm, were deposited either on a silicon substrate or on a surface coated with polyethersulfone (PES), and the voids of the arrays were filled with poly(ferrocenylmethylphenylsilane) (PFMPS). Argon ion sputtering removed the excess PFMPS on the particles which enabled removal of the particles with HF. Further pattern transfer steps with reactive ion etching for different time intervals provided structures in silicon or in a PES layer. Free-standing PES membranes exhibiting regular arrays of circular holes with high porosity were fabricated by using cellulose acetate as a sacrificial layer. The pores obtained on silicon substrates after etching were used as molds for nanoimprint lithography (NIL). A combination of the techniques of nanosphere lithography (NSL) and NIL has resulted in 3D nanostructures with a hemispherical shape (inherited from the nanoparticles) which was obtained both in silicon and in PMMA.

  17. Cast and 3D printed ion exchange membranes for monolithic microbial fuel cell fabrication

    NASA Astrophysics Data System (ADS)

    Philamore, Hemma; Rossiter, Jonathan; Walters, Peter; Winfield, Jonathan; Ieropoulos, Ioannis

    2015-09-01

    We present novel solutions to a key challenge in microbial fuel cell (MFC) technology; greater power density through increased relative surface area of the ion exchange membrane that separates the anode and cathode electrodes. The first use of a 3D printed polymer and a cast latex membrane are compared to a conventionally used cation exchange membrane. These new techniques significantly expand the geometric versatility available to ion exchange membranes in MFCs, which may be instrumental in answering challenges in the design of MFCs including miniaturisation, cost and ease of fabrication. Under electrical load conditions selected for optimal power transfer, peak power production (mean 10 batch feeds) was 11.39 μW (CEM), 10.51 μW (latex) and 0.92 μW (Tangoplus). Change in conductivity and pH of anolyte were correlated with MFC power production. Digital and environmental scanning electron microscopy show structural changes to and biological precipitation on membrane materials following long term use in an MFC. The cost of the novel membranes was lower than the conventional CEM. The efficacy of two novel membranes for ion exchange indicates that further characterisation of these materials and their fabrication techniques, shows great potential to significantly increase the range and type of MFCs that can be produced.

  18. New fabrication techniques for ring-array transducers for real-time 3D intravascular ultrasound.

    PubMed

    Light, Edward D; Lieu, Victor; Smith, Stephen W

    2009-10-01

    We have previously described miniature 2D array transducers integrated into a Cook Medical, Inc. vena cava filter deployment device. While functional, the fabrication technique was very labor intensive and did not lend itself well to efficient fabrication of large numbers of devices. We developed two new fabrication methods that we believe can be used to efficiently manufacture these types of devices in greater than prototype numbers. One transducer consisted of 55 elements operating near 5 MHz. The interelement spacing is 0.20 mm. It was constructed on a flat piece of copper-clad polyimide and then wrapped around an 11 French catheter of a Cook Medical, Inc. inferior vena cava (IVC) filter deployment device. We used a braided wiring technology from Tyco Electronics Corp. to connect the elements to our real-time 3D ultrasound scanner. Typical measured transducer element bandwidth was 20% centered at 4.7 MHz and the 50 Omega round trip insertion loss was --82 dB. The mean of the nearest neighbor cross talk was -37.0 dB. The second method consisted of a 46-cm long single layer flex circuit from MicroConnex that terminates in an interconnect that plugs directly into our system cable. This transducer had 70 elements at 0.157 mm interelement spacing operating at 4.8 MHz. Typical measured transducer element bandwidth was 29% and the 50 Omega round trip insertion loss was -83 dB. The mean of the nearest neighbor cross talk was -33.0 dB. PMID:20458877

  19. Novel 3D modeling methods for virtual fabrication and EDA compatible design of MEMS via parametric libraries

    NASA Astrophysics Data System (ADS)

    Schröpfer, Gerold; Lorenz, Gunar; Rouvillois, Stéphane; Breit, Stephen

    2010-06-01

    This paper provides a brief summary of the state-of-the-art of MEMS-specific modeling techniques and describes the validation of new models for a parametric component library. Two recently developed 3D modeling tools are described in more detail. The first one captures a methodology for designing MEMS devices and simulating them together with integrated electronics within a standard electronic design automation (EDA) environment. The MEMS designer can construct the MEMS model directly in a 3D view. The resulting 3D model differs from a typical feature-based 3D CAD modeling tool in that there is an underlying behavioral model and parametric layout associated with each MEMS component. The model of the complete MEMS device that is shared with the standard EDA environment can be fully parameterized with respect to manufacturing- and design-dependent variables. Another recent innovation is a process modeling tool that allows accurate and highly realistic visualization of the step-by-step creation of 3D micro-fabricated devices. The novelty of the tool lies in its use of voxels (3D pixels) rather than conventional 3D CAD techniques to represent the 3D geometry. Case studies for experimental devices are presented showing how the examination of these virtual prototypes can reveal design errors before mask tape out, support process development before actual fabrication and also enable failure analysis after manufacturing.

  20. In Situ Fabrication of 3D Ag@ZnO Nanostructures for Microfluidic Surface-Enhanced Raman Scattering Systems

    PubMed Central

    2015-01-01

    In this work, we develop an in situ method to grow highly controllable, sensitive, three-dimensional (3D) surface-enhanced Raman scattering (SERS) substrates via an optothermal effect within microfluidic devices. Implementing this approach, we fabricate SERS substrates composed of Ag@ZnO structures at prescribed locations inside microfluidic channels, sites within which current fabrication of SERS structures has been arduous. Conveniently, properties of the 3D Ag@ZnO nanostructures such as length, packing density, and coverage can also be adjusted by tuning laser irradiation parameters. After exploring the fabrication of the 3D nanostructures, we demonstrate a SERS enhancement factor of up to ∼2 × 106 and investigate the optical properties of the 3D Ag@ZnO structures through finite-difference time-domain simulations. To illustrate the potential value of our technique, low concentrations of biomolecules in the liquid state are detected. Moreover, an integrated cell-trapping function of the 3D Ag@ZnO structures records the surface chemical fingerprint of a living cell. Overall, our optothermal-effect-based fabrication technique offers an effective combination of microfluidics with SERS, resolving problems associated with the fabrication of SERS substrates in microfluidic channels. With its advantages in functionality, simplicity, and sensitivity, the microfluidic-SERS platform presented should be valuable in many biological, biochemical, and biomedical applications. PMID:25402207

  1. Fabrication of 3D Scaffolds with Nano-Hydroxyapatite for Improving the Preosteoblast Cell-Biological Performance.

    PubMed

    Roh, Hee-Sang; Myung, Sung-Woon; Jung, Sang-Chul; Kim, Byung-Hoon

    2015-08-01

    Three-dimensional (3D) scaffolds fabricated by rapid prototyping techniques have many merits for tissue engineering applications, due to its controllable properties such as porosity, pore size and structural shape. Nonetheless, low cell seeding efficiency remains drawback. In this study, poly-caprolactone (PCL) composite 3D extruded scaffolds were modified with nano hydroxyapatite (n-HAp). PCL/n-HAp 3D scaffold surface was treated with oxygen plasma to improve the preosteoblast cell seeding efficiency and proliferation. The results indicate that oxygen plasma is useful technique to improve the cell affinity. PMID:26369121

  2. 3D polycarprolactone (PCL) scaffold with hierarchical structure fabricated by a piezoelectric transducer (PZT)-assisted bioplotter

    NASA Astrophysics Data System (ADS)

    Kim, Geun Hyung; Son, Joon Gon

    2009-03-01

    The 3D bioplotter, which is one of the rapid-prototyping systems, enables us to produce the design-based scaffolds which could control good mechanical properties and pore structures for mimicking human organs. Although the plotting system has several advantages to fabricate a variety of designed scaffolds, the main disadvantage of scaffolds fabricated by the system is that the strand surfaces are too smooth and tend to discourage initial cell attachment within the scaffolds. To overcome the problem, we suggest a new 3D plotting method supplemented by piezoelectric vibration system for fabricating scaffolds that have hierarchical surface structures, which increase the surface roughness of the scaffold without any additional chemical process. The surface-modified 3D scaffold exhibited various positive qualities including enhanced compressive modulus and improved initial cell attachment and proliferation. Cell culturing results demonstrated that the interactions between chondrocytes and the scaffold were much more favorable than those between the cells and conventionally plotted 3D scaffolds. This process provides a feasible new technique for fabricating high-quality 3D scaffolds for tissue engineering applications.

  3. Characterization, fabrication, and analysis of soft dielectric elastomer actuators capable of complex 3D deformation

    NASA Astrophysics Data System (ADS)

    Lai, William

    Inspired by nature, the development of soft actuators has drawn large attention to provide higher flexibility and allow adaptation to more complex environment. This thesis is focused on utilizing electroactive polymers as active materials to develop soft planar dielectric elastomer actuators capable of complex 3D deformation. The potential applications of such soft actuators are in flexible robotic arms and grippers, morphing structures and flapping wings for micro aerial vehicles. The embraces design for a freestanding actuator utilizes the constrained deformation imposed by surface stiffeners on an electroactive membrane to avert the requirement of membrane pre-stretch and the supporting frames. The proposed design increases the overall actuator flexibility and degrees-of-freedom. Actuator design, fabrication, and performance are presented for different arrangement of stiffeners. Digital images correlation technique were utilized to evaluate the in-plane finite strain components, in order to elucidate the role of the stiffeners in controlling the three dimensional deformation. It was found that a key controlling factor was the localized deformation near the stiffeners, while the rest of the membrane would follow through. A detailed finite element modeling framework was developed with a user-material subroutine, built into the ABAQUS commercial finite element package. An experimentally calibrated Neo-Hookean based material model that coupled the applied electrical field to the actuator mechanical deformation was employed. The numerical model was used to optimize different geometrical features, electrode layup and stacking sequence of actuators. It was found that by splitting the stiffeners into finer segments, the force-stroke characteristics of actuator were able to be adjusted with stiffener configuration, while keeping the overall bending stiffness. The efficacy of actuators could also be greatly improved by increasing the stiffener periodicity. The developed

  4. Fabrication of 3D fractal structures using nanoscale anisotropic etching of single crystalline silicon

    NASA Astrophysics Data System (ADS)

    Berenschot, Erwin J. W.; Jansen, Henri V.; Tas, Niels R.

    2013-05-01

    When it comes to high-performance filtration, separation, sunlight collection, surface charge storage or catalysis, the effective surface area is what counts. Highly regular fractal structures seem to be the perfect candidates, but manufacturing can be quite cumbersome. Here it is shown--for the first time—that complex 3D fractals can be engineered using a recursive operation in conventional micromachining of single crystalline silicon. The procedure uses the built-in capability of the crystal lattice to form self-similar octahedral structures with minimal interference of the constructor. The silicon fractal can be used directly or as a mold to transfer the shape into another material. Moreover, they can be dense, porous, or like a wireframe. We demonstrate, after four levels of processing, that the initial number of octahedral structures is increased by a factor of 625. Meanwhile the size decreases 16 times down to 300 nm. At any level, pores of less than 100 nm can be fabricated at the octahedral vertices of the fractal. The presented technique supports the design of fractals with Hausdorff dimension D free of choice and up to D = 2.322.

  5. Monolithic transparent 3D dielectrophoretic micro-actuator fabricated by femtosecond laser

    NASA Astrophysics Data System (ADS)

    Yang, Tao; Bellouard, Yves

    2015-10-01

    We demonstrate a three-dimensional (3D) monolithic micro-actuator fabricated by non-ablative femtosecond laser micromachining and subsequent chemical etching. The actuating principle is based on dielectrophoresis. An analytical modeling of this actuation scheme is conducted, which is capable of performance prediction, parameter optimization and instability analysis. Static and dynamic characterizations are experimentally verified. An actuation range of 30 μm is well attainable; resonances are captured with an evaluated quality factor of 40 (measured in air) and a bandwidth of 5 Hz for the primary vertical resonance of 200 Hz. A settling time of 200 ms in transient response indicates the damping properties of such actuation scheme. This actuation principle suppresses the need for electrodes on the mobile, non-conductive component and is particularly interesting for moving transparent elements. Thanks to the flexibility of the manufacturing process, it can be coupled to other functionalities within monolithic transparent micro-electro-mechanical systems (MEMS) for applications like tunable optical couplers.

  6. Fabrication and characterization of metal-to-metal interconnect structures for 3-D integration

    NASA Astrophysics Data System (ADS)

    Huffman, Alan; Lannon, John; Lueck, Matthew; Gregory, Christopher; Temple, Dorota

    2009-03-01

    The use of collapsible (solder) bump interconnects in pixel detector hybridization has been shown to be very successful. However, as pixel sizes decrease, the use of non-collapsible metal-to-metal bump bonding methods is needed to push the interconnect dimensions smaller. Furthermore, these interconnects are compatible with 3D intgration technologies which are being considered to increase overall pixel and system performance. These metal-to-metal bonding structures provide robust mechanical and electrical connections and allow for a dramatic increase in pixel density. Of particular interest are Cu-Cu thermocompression bonding and Cu/Sn-Cu solid-liquid diffusion bonding processes. Working with Fermilab, RTI undertook a demonstration to show that these bump structures could be reliably used to interconnect devices designed with 20 micron I/O pitch. Cu and Cu/Sn bump fabrication processes were developed to provide a well-controlled surface topography necessary for the formation of low resistance, high yielding, and reliable interconnects. The electrical resistance and yield has been quantified based on electrical measurements of daisy chain test structures and the mechanical strength of the bonding has been quantified through die shear testing. The reliability has been characterized through studies of the impact of thermal exposure on the mechanical performance of the bonds. Cross-section SEM analysis, coupled with high resolution energy dispersive spectroscopy, has provided insight into the physical and chemical nature of the bonding interfaces and aided in the evaluation of the long-term stability of the bonds.

  7. Benchtop fabrication of PDMS microstructures by an unconventional photolithographic method

    PubMed Central

    Hwang, Chang Mo; Sim, Woo Young; Lee, Seung Hwan; Foudeh, Amir M; Bae, Hojae

    2010-01-01

    Poly(dimethylsiloxane) (PDMS) microstructures have been widely used in bio-microelectromechanical systems (bio-MEMS) for various types of analytical, diagnostic and therapeutic applications. However, PDMS-based soft lithographic techniques still use conventional microfabrication processes to generate a master mold, which requires access to clean room facilities and costly equipment. With the increasing use of these systems in various fields, the development of benchtop systems for fabricating microdevices is emerging as an important challenge in their widespread use. Here we demonstrate a simple, low-cost and rapid method to fabricate PDMS microstructures by using micropatterned poly(ethylene glycol) diacrylate (PEGDA) master molds. In this method, PEGDA microstructures were patterned on a glass substrate by photolithography under ambient conditions and by using simple tools. The resulting PEGDA structures were subsequently used to generate PDMS microstructures by standard molding in a reproducible and repeatable manner. The thickness of the PEGDA microstructures was controllable from 15 to 300 μm by using commonly available spacer materials. We also demonstrate the use of this method to fabricate microfluidic channels capable of generating concentration gradients. In addition, we fabricated PEGDA microstructures by photolithography from the light generated from commonly available laminar cell culture hood. These data suggest that this approach could be beneficial for fabricating low-cost PDMS-based microdevices in resource limited settings. PMID:21076185

  8. Application of synchrotron X-ray microtomography for visualizing bacterial biofilms 3D microstructure in porous media.

    PubMed

    Rolland du Roscoat, S; Martins, J M F; Séchet, P; Vince, E; Latil, P; Geindreau, C

    2014-06-01

    The development of reliable models to accurately predict biofilm growth in porous media relies on a good knowledge of the temporal evolution of biofilms structure within the porous network. Since little is known on the true 3D structure of biofilms developed in porous media, this work aimed at developing a new experimental protocol to visualize the 3D microstructure of bacterial biofilms in porous media. The main originality of the proposed procedure lies on the combination of the more recent advances in synchrotron microtomography (Paganin mode) and of a new contrast agent (1-chloronaphtalene) that has never been applied to biofilm visualization. It is shown that the proposed methodology takes advantage of the contrasting properties of 1-chloronaphtalene to prevent some limitations observed with more classical contrast agents. A quantitative analysis of the microstructural properties (volume fractions and specific surface area) of bacterial biofilms developed in columns of clay beads is also proposed on the basis of the obtained 3D images. PMID:24293082

  9. Method of fabricating a high aspect ratio microstructure

    DOEpatents

    Warren, John B.

    2003-05-06

    The present invention is for a method of fabricating a high aspect ratio, freestanding microstructure. The fabrication method modifies the exposure process for SU-8, an negative-acting, ultraviolet-sensitive photoresist used for microfabrication whereby a UV-absorbent glass substrate, chosen for complete absorption of UV radiation at 380 nanometers or less, is coated with a negative photoresist, exposed and developed according to standard practice. This UV absorbent glass enables the fabrication of cylindrical cavities in a negative photoresist microstructures that have aspect ratios of 8:1.

  10. Oriented Nano-Microstructure-Assisted Controllable Fabrication of Metal-Organic Framework Membranes on Nickel Foam.

    PubMed

    Sun, Yuxiu; Yang, Fan; Wei, Qi; Wang, Naixin; Qin, Xi; Zhang, Shaokang; Wang, Bin; Nie, Zuoren; Ji, Shulan; Yan, Hui; Li, Jian-Rong

    2016-03-01

    Oriented nano-microstructure-assisted controllable fabrication, a facile and versatile preparation strategy, is developed to fabricate metal-organic framework (MOF) membranes. With this method, several MOF membranes with tailored structures are prepared, including HKUST-1 (with 3D pores) and M3 (HCOO)6 (with 1D pores; M = Co, Mn, and Mg) membranes, which demonstrate good performances in gas separations. PMID:26808691

  11. Design, simulation, fabrication, and preliminary tests of 3D CMS pixel detectors for the super-LHC

    SciTech Connect

    Koybasi, Ozhan; Bortoletto, Daniela; Hansen, Thor-Erik; Kok, Angela; Hansen, Trond Andreas; Lietaer, Nicolas; Jensen, Geir Uri; Summanwar, Anand; Bolla, Gino; Kwan, Simon Wing Lok; /Fermilab

    2010-01-01

    The Super-LHC upgrade puts strong demands on the radiation hardness of the innermost tracking detectors of the CMS, which cannot be fulfilled with any conventional planar detector design. The so-called 3D detector architectures, which feature columnar electrodes passing through the substrate thickness, are under investigation as a potential solution for the closest operation points to the beams, where the radiation fluence is estimated to reach 10{sup 16} n{sub eq}/cm{sup 2}. Two different 3D detector designs with CMS pixel readout electronics are being developed and evaluated for their advantages and drawbacks. The fabrication of full-3D active edge CMS pixel devices with p-type substrate has been successfully completed at SINTEF. In this paper, we study the expected post-irradiation behaviors of these devices with simulations and, after a brief description of their fabrication, we report the first leakage current measurement results as performed on wafer.

  12. Novel carbon-fiber microelectrode batch fabrication using a 3D-printed mold and polyimide resin.

    PubMed

    Trikantzopoulos, Elefterios; Yang, Cheng; Ganesana, Mallikarjunarao; Wang, Ying; Venton, B Jill

    2016-09-21

    Glass insulated carbon-fiber microelectrodes (CFMEs) are standard tools for the measurement of neurotransmitters. However, electrodes are fabricated individually and the glass can shatter, limiting application in higher order mammals. Here, we developed a novel microelectrode batch fabrication method using a 3D-printed mold and polyimide resin insulating agent. The 3D-printed mold is low cost, customizable to change the electrode shape, and allows 40 electrodes to be made simultaneously. The polyimide resin is biocompatible, quick to cure, and does not adhere to the plastic mold. The electrodes were tested for the response to dopamine with fast-scan cyclic voltammetry both in vitro and in vivo and performed similarly to traditional glass-insulated electrodes, but with lower background currents. Thus, polyimide-insulated electrodes can be mass-produced using a 3D-printed mold and are an attractive alternative for making cheap, biocompatible microelectrodes. PMID:27536741

  13. Fabrication of continuous flow microfluidics device with 3D electrode structures for high throughput DEP applications using mechanical machining.

    PubMed

    Zeinali, Soheila; Çetin, Barbaros; Oliaei, Samad Nadimi Bavil; Karpat, Yiğit

    2015-07-01

    Microfluidics is the combination of micro/nano fabrication techniques with fluid flow at microscale to pursue powerful techniques in controlling and manipulating chemical and biological processes. Sorting and separation of bio-particles are highly considered in diagnostics and biological analyses. Dielectrophoresis (DEP) has offered unique advantages for microfluidic devices. In DEP devices, asymmetric pair of planar electrodes could be employed to generate non-uniform electric fields. In DEP applications, facing 3D sidewall electrodes is considered to be one of the key solutions to increase device throughput due to the generated homogeneous electric fields along the height of microchannels. Despite the advantages, fabrication of 3D vertical electrodes requires a considerable challenge. In this study, two alternative fabrication techniques have been proposed for the fabrication of a microfluidic device with 3D sidewall electrodes. In the first method, both the mold and the electrodes are fabricated using high precision machining. In the second method, the mold with tilted sidewalls is fabricated using high precision machining and the electrodes are deposited on the sidewall using sputtering together with a shadow mask fabricated by electric discharge machining. Both fabrication processes are assessed as highly repeatable and robust. Moreover, the two methods are found to be complementary with respect to the channel height. Only the manipulation of particles with negative-DEP is demonstrated in the experiments, and the throughput values up to 105 particles / min is reached in a continuous flow. The experimental results are compared with the simulation results and the limitations on the fabrication techniques are also discussed. PMID:25808433

  14. FOREWORD: Focus on Novel Nanoelectromechanical 3D Structures: Fabrication and Properties Focus on Novel Nanoelectromechanical 3D Structures: Fabrication and Properties

    NASA Astrophysics Data System (ADS)

    Yamada, Shooji; Yamaguchi, Hiroshi; Ishihara, Sunao

    2009-06-01

    Microelectromechanical systems (MEMS) are widely used small electromechanical systems made of micrometre-sized components. Presently, we are witnessing a transition from MEMS to nanoelectromechanical systems (NEMS), which comprise devices integrating electrical and mechanical functionality on the nanoscale and offer new exciting applications. Similarly to MEMS, NEMS typically include a central transistor-like nanoelectronic unit for data processing, as well as mechanical actuators, pumps, and motors; and they may combine with physical, biological and chemical sensors. In the transition from MEMS to NEMS, component sizes need to be reduced. Therefore, many fabrication methods previously developed for MEMS are unsuitable for the production of high-precision NEMS components. The key challenge in NEMS is therefore the development of new methods for routine and reproducible nanofabrication. Two complementary types of method for NEMS fabrication are available: 'top-down' and 'bottom-up'. The top-down approach uses traditional lithography technologies, whereas bottom-up techniques include molecular self-organization, self-assembly and nanodeposition. The NT2008 conference, held at Ishikawa High-Tech Conference Center, Ishikawa, Japan, between 23-25 October 2008, focused on novel NEMS fabricated from new materials and on process technologies. The topics included compound semiconductors, small mechanical structures, nanostructures for micro-fluid and bio-sensors, bio-hybrid micro-machines, as well as their design and simulation. This focus issue compiles seven articles selected from 13 submitted manuscripts. The articles by Prinz et al and Kehrbusch et al introduce the frontiers of the top-down production of various operational NEMS devices, and Kometani et al present an example of the bottom-up approach, namely ion-beam induced deposition of MEMS and NEMS. The remaining articles report novel technologies for biological sensors. Taira et al have used manganese nanoparticles

  15. Method for the fabrication of three-dimensional microstructures by deep X-ray lithography

    DOEpatents

    Sweatt, William C.; Christenson, Todd R.

    2005-04-05

    A method for the fabrication of three-dimensional microstructures by deep X-ray lithography (DXRL) comprises a masking process that uses a patterned mask with inclined mask holes and off-normal exposures with a DXRL beam aligned with the inclined mask holes. Microstructural features that are oriented in different directions can be obtained by using multiple off-normal exposures through additional mask holes having different orientations. Various methods can be used to block the non-aligned mask holes from the beam when using multiple exposures. A method for fabricating a precision 3D X-ray mask comprises forming an intermediate mask and a master mask on a common support membrane.

  16. Gold nanoparticle-mediated fluorescence enhancement by two-photon polymerized 3D microstructures

    NASA Astrophysics Data System (ADS)

    Aekbote, Badri L.; Schubert, Félix; Ormos, Pál; Kelemen, Lóránd

    2014-12-01

    Fluorescence enhancement achieved by functionalized microstructures made by two-photon polymerization (TPP) is reported for the first time. Microstructures of various shapes made of SU-8 photoresist were prepared and coated with gold nanoparticles (NP) of 80 nm. Localized fluorescence enhancement was demonstrated by microstructures equipped with tips of sub-micron dimensions. The enhancement was realized by positioning the NP-coated structures over fluorescent protein layers. Two fluorophores with their absorption in the red and in the green region of the VIS spectrum were used. Laser scanning confocal microscopy was used to quantify the enhancement. The enhancement factor was as high as 6 in areas of several square-micrometers and more than 3 in the case of local enhancement, comparable with literature values for similar nanoparticles. The structured pattern of the observed fluorescence intensity indicates a classic enhancement mechanism realized by standing waves over reflecting surfaces. With further development mobile microtools made by TPP and functionalized by metal NPs can be actuated by optical tweezers and position to any fluorescent micro-object, such as single cells to realize localized, targeted fluorescence enhancement.

  17. Cross-correlative 3D micro-structural investigation of human bone processed into bone allografts.

    PubMed

    Singh, Atul Kumar; Gajiwala, Astrid Lobo; Rai, Ratan Kumar; Khan, Mohd Parvez; Singh, Chandan; Barbhuyan, Tarun; Vijayalakshmi, S; Chattopadhyay, Naibedya; Sinha, Neeraj; Kumar, Ashutosh; Bellare, Jayesh R

    2016-05-01

    Bone allografts (BA) are a cost-effective and sustainable alternative in orthopedic practice as they provide a permanent solution for preserving skeletal architecture and function. Such BA however, must be processed to be disease free and immunologically safe as well as biologically and clinically useful. Here, we have demonstrated a processing protocol for bone allografts and investigated the micro-structural properties of bone collected from osteoporotic and normal human donor samples. In order to characterize BA at different microscopic levels, a combination of techniques such as Solid State Nuclear Magnetic Resonance (ssNMR), Scanning Electron Microscope (SEM), micro-computed tomography (μCT) and Thermal Gravimetric Analysis (TGA) were used for delineating the ultra-structural property of bone. ssNMR revealed the extent of water, collagen fine structure and crystalline order in the bone. These were greatly perturbed in the bone taken from osteoporotic bone donor. Among the processing methods analyzed, pasteurization at 60 °C and radiation treatment appeared to substantially alter the bone integrity. SEM study showed a reduction in Ca/P ratio and non-uniform distribution of elements in osteoporotic bones. μ-CT and MIMICS (Materialize Interactive Medical Image Control System) demonstrated that pasteurization and radiation treatment affects the BA morphology and cause a shift in the HU unit. However, the combination of all these processes restored all-important parameters that are critical for BA integrity and sustainability. Cross-correlation between the various probes we used quantitatively demonstrated differences in morphological and micro-structural properties between BA taken from normal and osteoporotic human donor. Such details could also be instrumental in designing an appropriate bone scaffold. For the best restoration of bone microstructure and to be used as a biomaterial allograft, a step-wise processing method is recommended that preserves all

  18. A validated 3D microstructure-based constitutive model of coronary artery adventitia.

    PubMed

    Chen, Huan; Guo, Xiaomei; Luo, Tong; Kassab, Ghassan S

    2016-07-01

    A structure-based model that accurately predicts micro- or macromechanical behavior of blood vessels is necessary to understand vascular physiology. Based on recently measured microstructural data, we propose a three-dimensional microstructural model of coronary adventitia that incorporates the elastin and collagen distributions throughout the wall. The role of ground substance was found to be negligible under physiological axial stretch λz = 1.3, based on enzyme degradation of glycosaminoglycans in swine coronary adventitia (n = 5). The thick collagen bundles of outer adventitia (n = 4) were found to be undulated and unengaged at physiological loads, whereas the inner adventitia consisted of multiple sublayers of entangled fibers that bear the majority of load at higher pressures. The microstructural model was validated against biaxial (inflation and extension) experiments of coronary adventitia (n = 5). The model accurately predicted the nonlinear responses of the adventitia, even at high axial force (axial stretch ratio λz = 1.5). The model also enabled a reliable estimation of material parameters of individual fibers that were physically reasonable. A sensitivity analysis was performed to assess the effect of using mean values of the distributions for fiber orientation and waviness as opposed to the full distributions. The simplified mean analysis affects the fiber stress-strain relation, resulting in incorrect estimation of mechanical parameters, which underscores the need for measurements of fiber distribution for a rigorous analysis of fiber mechanics. The validated structure-based model of coronary adventitia provides a deeper understanding of vascular mechanics in health and can be extended to disease conditions. PMID:27174925

  19. 3D Microstructural Architecture of Muscle Attachments in Extant and Fossil Vertebrates Revealed by Synchrotron Microtomography

    PubMed Central

    Sanchez, Sophie; Dupret, Vincent; Tafforeau, Paul; Trinajstic, Katherine M.; Ryll, Bettina; Gouttenoire, Pierre-Jean; Wretman, Lovisa; Zylberberg, Louise; Peyrin, Françoise; Ahlberg, Per E.

    2013-01-01

    Background Firm attachments binding muscles to skeleton are crucial mechanical components of the vertebrate body. These attachments (entheses) are complex three-dimensional structures, containing distinctive arrangements of cells and fibre systems embedded in the bone, which can be modified during ontogeny. Until recently it has only been possible to obtain 2D surface and thin section images of entheses, leaving their 3D histology largely unstudied except by extrapolation from 2D data. Entheses are frequently preserved in fossil bones, but sectioning is inappropriate for rare or unique fossil material. Methodology/Principal Findings Here we present the first non-destructive 3D investigation, by propagation phase contrast synchrotron microtomography (PPC-SRµCT), of enthesis histology in extant and fossil vertebrates. We are able to identify entheses in the humerus of the salamander Desmognathus from the organization of bone-cell lacunae and extrinsic fibres. Statistical analysis of the lacunae differentiates types of attachments, and the orientation of the fibres, reflect the approximate alignment of the muscle. Similar histological structures, including ontogenetically related pattern changes, are perfectly preserved in two 380 million year old fossil vertebrates, the placoderm Compagopiscis croucheri and the sarcopterygian fish Eusthenopteron foordi. Conclusions/Significance We are able to determine the position of entheses in fossil vertebrates, the approximate orientation of the attached muscles, and aspects of their ontogenetic histories, from PPC-SRµCT data. Sub-micron microtomography thus provides a powerful tool for studying the structure, development, evolution and palaeobiology of muscle attachments. PMID:23468901

  20. Nonlinear 3D projection printing of concave hydrogel microstructures for long-term multicellular spheroid and embryoid body culture.

    PubMed

    Hribar, K C; Finlay, D; Ma, X; Qu, X; Ondeck, M G; Chung, P H; Zanella, F; Engler, A J; Sheikh, F; Vuori, K; Chen, S C

    2015-06-01

    Long-term culture and monitoring of individual multicellular spheroids and embryoid bodies (EBs) remains a challenge for in vitro cell propagation. Here, we used a continuous 3D projection printing approach - with an important modification of nonlinear exposure - to generate concave hydrogel microstructures that permit spheroid growth and long-term maintenance, without the need for spheroid transfer. Breast cancer spheroids grown to 10 d in the concave structures showed hypoxic cores and signs of necrosis using immunofluorescent and histochemical staining, key features of the tumor microenvironment in vivo. EBs consisting of induced pluripotent stem cells (iPSCs) grown on the hydrogels demonstrated narrow size distribution and undifferentiated markers at 3 d, followed by signs of differentiation by the presence of cavities and staining of the three germ layers at 10 d. These findings demonstrate a new method for long-term (e.g. beyond spheroid formation at day 2, and with media exchange) 3D cell culture that should be able to assist in cancer spheroid studies as well as embryogenesis and patient-derived disease modeling with iPSC EBs. PMID:25900329

  1. Nonlinear 3D Projection Printing of Concave Hydrogel Microstructures for Long-Term Multicellular Spheroid and Embryoid Body Culture

    PubMed Central

    Hribar, K.C; Finlay, D.; Ma, X.; Qu, X.; Ondeck, M. G.; Chung, P. H.; Zanella, F.; Engler, A. J.; Sheikh, F.; Vuori, K.; Chen, S.

    2015-01-01

    Long-term culture and monitoring of individual multicellular spheroids and embryoid bodies (EBs) remains a challenge for in vitro cell propogation. Here, we used a continuous 3D projection printing approach – with an important modification of nonlinear exposure — to generate concave hydrogel microstructures that permit spheroid growth and long-term maintenance, without the need for spheroid transfer. Breast cancer spheroids grown to 10 d in the concave structures showed hypoxic cores and signs of necrosis using immunofluorescent and histochemical staining, key features of the tumor microenvironment in vivo. EBs consisting of induced pluripotent stem cells (iPSCs) grown on the hydrogels demonstrated narrow size distribution and undifferentiated markers at 3 d, followed by signs of differentiation by the presence of cavities and staining of the three germ layers at 10 d. These findings demonstrate a new method for long-term (e.g. beyond spheroid formation at day 2, and with media exchange) 3D cell culture that should be able to assist in cancer spheroid studies as well as embryogenesis and patient-derived disease modeling with iPSC EBs. PMID:25900329

  2. Fabrication of 3D tissue equivalent: an in vitro platform for understanding collagen evolution in healthy and diseased models

    NASA Astrophysics Data System (ADS)

    Urciuolo, F.; Imparato, G.; Casale, C.; Scamardella, S.; Netti, P.

    2013-04-01

    In this study we realized a three-dimensional human dermis equivalent (3D-HDE) and, by exploiting multi-photon microscopy (MPM) we validated its use as an in vitro model to study collagen network re-arrangement under simulated solar exposure. The realization of 3D-HDE has been pursed by means of a bottom-up tissue engineering strategy that comprises firstly the fabrication of micron sized tissue building blocks and then their assembly in a 3D tissue construct. The building blocks injected in a maturation chamber, and cultured under optimized culture condition, were able to fuse due to the establishment of cell-cell and cell-extra cellular matrix (ECM) interactions that induced a biological sintering process resulting in 3D-HDE production. The final 3D tissue was made-up by fibroblasts embedded in their own ECM rich in endogenous collagen type I, resembling the composition and the architecture of native human dermis. Second Harmonic Generation (SHG) and Two-Photon Excited Fluorescence (TPEF) imaging have been exploited to assess modification in collagen assembly before and after UV irradiation. Textural features and SHG to TPFE ratio of the endogenous ECM within 3D-HDE have been shown to vary after UVA irradiation, proving the hypothesis that the 3DHDE realized can be used as biological platform in vitro to study ECM modifications induced by photo-damage.

  3. Hot embossing for fabrication of a microfluidic 3D cell culture platform

    PubMed Central

    Jeon, Jessie S.; Chung, Seok; Kamm, Roger D.; Charest, Joseph L.

    2011-01-01

    Clinically relevant studies of cell function in vitro require a physiologically-representative microenvironment possessing aspects such as a 3D extracellular matrix (ECM) and controlled biochemical and biophysical parameters. A polydimethylsiloxane (PDMS) microfluidic system with a 3D collagen gel has previously served for analysis of factors inducing different responses of cells in a 3D microenvironment under controlled biochemical and biophysical parameters. In the present study, applying the known commercially-viable manufacturing methods to a cyclic olefin copolymer (COC) material resulted in a microfluidic device with enhanced 3D gel capabilities, controlled surface properties, and improved potential to serve high-volume applications. Hot embossing and roller lamination molded and sealed the microfluidic device. A combination of oxygen plasma and thermal treatments enhanced the sealing, ensured proper placement of the 3D gel, and created controlled and stable surface properties within the device. Culture of cells in the new device indicated no adverse effects of the COC material or processing as compared to previous PDMS devices. The results demonstrate a methodology to transition microfludic devices for 3D cell culture from scientific research to high-volume applications with broad clinical impact. PMID:21113663

  4. 3D-analysis of plant microstructures: advantages and limitations of synchrotron X-ray microtomography

    NASA Astrophysics Data System (ADS)

    Matsushima, U.; Graf, W.; Zabler, S.; Manke, I.; Dawson, M.; Choinka, G.; Hilger, A.; Herppich, W. B.

    2013-01-01

    Synchrotron X-ray computer microtomography was used to analyze the microstructure of rose peduncles. Samples from three rose cultivars, differing in anatomy, were scanned to study the relation between tissue structure and peduncles mechanical strength. Additionally, chlorophyll fluorescence imaging and conventional light microscopy was applied to quantify possible irradiation-induced damage to plant physiology and tissue structure. The spatial resolution of synchrotron X-ray computer microtomography was sufficiently high to investigate the complex tissues of intact rose peduncles without the necessity of any preparation. However, synchrotron X-radiation induces two different types of damage on irradiated tissues. First, within a few hours after first X-ray exposure, there is a direct physical destruction of cell walls. In addition, a slow and delayed destruction of chlorophyll and, consequently, of photosynthetic activity occurred within hours/ days after the exposure. The results indicate that synchrotron X-ray computer microtomography is well suited for three-dimensional visualization of the microstructure of rose peduncles. However, in its current technique, synchrotron X-ray computer microtomography is not really non-destructive but induce tissue damage. Hence, this technique needs further optimization before it can be applied for time-series investigations of living plant materials

  5. 3D visualization of tissue microstructures using optical coherence tomography needle probes

    NASA Astrophysics Data System (ADS)

    Kirk, Rodney W.; McLaughlin, Robert A.; Quirk, Bryden C.; Curatolo, Andrea; Sampson, David D.

    2011-05-01

    Optical coherence tomography (OCT) needle probes use miniaturized focusing optics encased in a hypodermic needle. Needle probes can scan areas of the body that are too deep to be imaged by other OCT systems. This paper presents an OCT needle probe-based system that is capable of acquiring three-dimensional scans of tissue structures. The needle can be guided to a target area and scans acquired by rotating and pulling-back the probe. The system is demonstrated using ex vivo human lymph node and sheep lung samples. Multiplanar reconstructions are shown of both samples, as well as the first published 3D volume rendering of lung tissue acquired with an OCT needle probe.

  6. Reliability of self-assembled 3D microstructures: snap-through modeling and experimental validation

    NASA Astrophysics Data System (ADS)

    Millet, Olivier; Buchaillot, Lionel; Quevy, Emmanuel; Collard, Dominique

    2001-04-01

    This work considers the reliability of an elementary 3D structure, and particularly the response of a homogeneous, clamped-clamped polysilicon microfabricated beam, buckling under the compressive force produced by Scratch-Drive Actuators (SDA). First, using Galerkin's method, the governing partial differential equation reduced to a modified Duffing equation and was solved by the harmonic balance method. Besides the solution of simple harmonic motion (SHM) and superharmonic motion (SPHM) were found numerically using a Newton iteration method. Then, the study of continuity -- of these solutions -- allowed to analyze the stability boundaries. Finally, Runge-Kutta numerical integration method was used to investigate the snap-through problem. Intermittent, as well as continuous, snap-through behavior was obtained. The theoretical results agreed well with the experiments.

  7. Direct fabrication of complex 3D hierarchical nanostructures by reactive ion etching of hollow sphere colloidal crystals.

    PubMed

    Zhong, Kuo; Li, Jiaqi; Van Cleuvenbergen, Stijn; Clays, Koen

    2016-09-21

    Direct reactive ion etching (RIE) of hollow SiO2 sphere colloidal crystals (HSCCs) is employed as a facile, low-cost method to fabricate complex three-dimensional (3D) hierarchical nanostructures. These multilayered structures are gradually transformed into nanostructures of increasing complexity by controlling the etching time, without complicated procedures (no mask needed). The resulting 3D topologies are unique, and cannot be obtained through traditional approaches. The formation mechanism of these structures is explained in detail by geometrical modeling during the different etching stages, through shadow effects of the higher layers. SEM images confirm the modeled morphological changes. The nanostructures obtained by our approach show very fine features as small as ∼30 nm. Our approach opens new avenues to directly obtain complex 3D nanostructures from colloidal crystals and can find applications in sensing, templating, and catalysis where fine tuning the specific surface might be critical. PMID:27545098

  8. Light-driven 3D droplet manipulation on flexible optoelectrowetting devices fabricated by a simple spin-coating method.

    PubMed

    Jiang, Dongyue; Park, Sung-Yong

    2016-05-21

    Technical advances in electrowetting-on-dielectric (EWOD) over the past few years have extended our attraction to three-dimensional (3D) devices capable of providing more flexibility and functionality with larger volumetric capacity than conventional 2D planar ones. However, typical 3D EWOD devices require complex and expensive fabrication processes for patterning and wiring of pixelated electrodes that also restrict the minimum droplet size to be manipulated. Here, we present a flexible single-sided continuous optoelectrowetting (SCOEW) device which is not only fabricated by a spin-coating method without the need for patterning and wiring processes, but also enables light-driven 3D droplet manipulations. To provide photoconductive properties, previous optoelectrowetting (OEW) devices have used amorphous silicon (a-Si) typically fabricated through high-temperature processes over 300 °C such as CVD or PECVD. However, most of the commercially-available flexible substrates such as polyethylene terephthalate (PET) and polyethylene naphthalate (PEN) experience serious thermal deformation under such high-temperature processes. Because of this compatibility issue of conventional OEW devices with flexible substrates, light-driven 3D droplet manipulations have not yet been demonstrated on flexible substrates. Our study overcomes this compatibility issue by using a polymer-based photoconductive material, titanium oxide phthalocyanine (TiOPc) and thus SCOEW devices can be simply fabricated on flexible substrates through a low-cost, spin-coating method. In this paper, analytical studies were conducted to understand the effects of light patterns on static contact angles and EWOD forces. For experimental validations of our study, flexible SCOEW devices were successfully fabricated through the TiOPc-based spin-coating method and light-driven droplet manipulations (e.g. transportation, merging, and splitting) have been demonstrated on various 3D terrains such as inclined

  9. Fabrication of dielectric and metallo-dielectric 3D nanostructures by direct laser writing and electroless plating

    NASA Astrophysics Data System (ADS)

    Radke, André; Wolff, Frank; Giessen, Harald; Klotzbücher, Thomas

    2010-02-01

    Direct laser writing via two-photon absorption allows the fabrication of three-dimensional dielectric structures with submicron resolution by tightly focusing ultrashort laser pulses into a photo-sensitive material with a high-resolution microscope objective and scanning the laser focus relative to the material. Woodpile photonic crystals fabricated with this method show a characteristic dip in transmission at near-infrared wavelengths. The spectral position of this transmission dip scales with the grating period of the fabricated crystals. Metallo-dielectric structures can be obtained by first fabricating dielectric templates with direct laser writing and subsequently coating the templates with a thin conformal metal film by electroless plating. Contiguous and conducting silver films can be deposited even on convoluted 3D geometries.

  10. Construction and Myogenic Differentiation of 3D Myoblast Tissues Fabricated by Fibronectin-Gelatin Nanofilm Coating

    PubMed Central

    Gribova, Varvara; Liu, Chen Yun; Nishiguchi, Akihiro; Matsusaki, Michiya; Boudou, Thomas; Picart, Catherine; Akashi, Mitsuru

    2016-01-01

    In this study, we used a recently developed approach of coating the cells with fibronectin-gelatin nanofilms to build 3D skeletal muscle tissue models. We constructed the microtissues from C2C12 myoblasts and subsequently differentiated them to form muscle-like tissue. The thickness of the constructs could be successfully controlled by altering the number of seeded cells. We were able to build up to ~ 76 µm thick 3D constructs that formed multinucleated myotubes. We also found that Rho-kinase inhibitor Y27632 improved myotube formation in thick constructs. Our approach makes it possible to rapidly form 3D muscle tissues and is promising for the in vitro construction of physiologically relevant human skeletal muscle tissue models. PMID:27125461

  11. Construction and myogenic differentiation of 3D myoblast tissues fabricated by fibronectin-gelatin nanofilm coating.

    PubMed

    Gribova, Varvara; Liu, Chun-Yen; Nishiguchi, Akihiro; Matsusaki, Michiya; Boudou, Thomas; Picart, Catherine; Akashi, Mitsuru

    2016-06-01

    In this study, we used a recently developed approach of coating the cells with fibronectin-gelatin nanofilms to build 3D skeletal muscle tissue models. We constructed the microtissues from C2C12 myoblasts and subsequently differentiated them to form muscle-like tissue. The thickness of the constructs could be successfully controlled by altering the number of seeded cells. We were able to build up to ∼76 μm thick 3D constructs that formed multinucleated myotubes. We also found that Rho-kinase inhibitor Y27632 improved myotube formation in thick constructs. Our approach makes it possible to rapidly form 3D muscle tissues and is promising for the in vitro construction of physiologically relevant human skeletal muscle tissue models. PMID:27125461

  12. Electrochemical fabrication of 2D and 3D nickel nanowires using porous anodic alumina templates

    NASA Astrophysics Data System (ADS)

    Mebed, A. M.; Abd-Elnaiem, Alaa M.; Al-Hosiny, Najm M.

    2016-06-01

    Mechanically stable nickel (Ni) nanowires array and nanowires network were synthesized by pulse electrochemical deposition using 2D and 3D porous anodic alumina (PAA) templates. The structures and morphologies of as-prepared films were characterized by X-ray diffraction and scanning electron microscopy, respectively. The grown Ni nanowire using 3D PAA revealed more strength and larger surface area than has grown Ni use 2D PAA template. The prepared nanowires have a face-centered cubic crystal structure with average grain size 15 nm, and the preferred orientation of the nucleation of the nanowires is (111). The diameter of the nanowires is about 50-70 nm with length 3 µm. The resulting 3D Ni nanowire lattice, which provides enhanced mechanical stability and an increased surface area, benefits energy storage and many other applications which utilize the large surface area.

  13. Spun-wrapped aligned nanofiber (SWAN) lithography for fabrication of micro/nano-structures on 3D objects.

    PubMed

    Ye, Zhou; Nain, Amrinder S; Behkam, Bahareh

    2016-07-01

    Fabrication of micro/nano-structures on irregularly shaped substrates and three-dimensional (3D) objects is of significant interest in diverse technological fields. However, it remains a formidable challenge thwarted by limited adaptability of the state-of-the-art nanolithography techniques for nanofabrication on non-planar surfaces. In this work, we introduce Spun-Wrapped Aligned Nanofiber (SWAN) lithography, a versatile, scalable, and cost-effective technique for fabrication of multiscale (nano to microscale) structures on 3D objects without restriction on substrate material and geometry. SWAN lithography combines precise deposition of polymeric nanofiber masks, in aligned single or multilayer configurations, with well-controlled solvent vapor treatment and etching processes to enable high throughput (>10(-7) m(2) s(-1)) and large-area fabrication of sub-50 nm to several micron features with high pattern fidelity. Using this technique, we demonstrate whole-surface nanopatterning of bulk and thin film surfaces of cubes, cylinders, and hyperbola-shaped objects that would be difficult, if not impossible to achieve with existing methods. We demonstrate that the fabricated feature size (b) scales with the fiber mask diameter (D) as b(1.5)∝D. This scaling law is in excellent agreement with theoretical predictions using the Johnson, Kendall, and Roberts (JKR) contact theory, thus providing a rational design framework for fabrication of systems and devices that require precisely designed multiscale features. PMID:27283144

  14. Fabrication and characterization of direct-written 3D TiO2 woodpile electromagnetic bandgap structures

    NASA Astrophysics Data System (ADS)

    Li, Ji-Jiao; Li, Bo; Peng, Qin-Mei; Zhou, Ji; Li, Long-Tu

    2014-09-01

    Three groups of three-dimensional (3D) TiO2 woodpile electromagnetic gap materials with tailed rheological properties were developed for direct-written fabrication. Appropriate amount of polyethyleneimine (PEI) dispersants allow the preparation of TiO2 inks with a high solid content of 42 vol.%, which enables them to flow through the nozzles easily. The inks exhibit pseudoplastic behavior. The measured microwave characteristics of the results agree well with simulations based on plane wave expansion (PWE).

  15. Superhydrophobic surfaces fabricated from nano- and microstructured cellulose stearoyl esters.

    PubMed

    Geissler, Andreas; Chen, Longquan; Zhang, Kai; Bonaccurso, Elmar; Biesalski, Markus

    2013-05-28

    Robust, superhydrophobic and self-cleaning films were fabricated using nano- or microstructured cellulose fatty acid esters, which were prepared via nanoprecipitation. The superhydrophobic films could be coated on diverse surfaces with non-uniform shapes by distinct coating techniques. PMID:23609473

  16. Submicron scale 3D investigation of kelyphyites after garnet: thermodynamics, crystallographic orientation, microstructure evolution and fluid-rock interactions

    NASA Astrophysics Data System (ADS)

    Dégi, Júlia; Török, Kálmán; Németh, Bianca; Rhede, Dieter; Takács, Ágnes; Habler, Gerlinde; Abart, Rainer

    2016-04-01

    Complex kelyphitic rims after garnet were studied in a lower crustal mafic granulite xenolith from the Bakony-Balaton Highland Volcanic Field, W-Hungary. The xenolith is dominated by a garnet granulite mineral assemblage equilibrated at 900 ° C, 1.4 GPa within the overthickened orogenic root of the Alps. Garnet breakdown was initiated during the extension of the Pannonian Basin and remained continuous until the xenoliths reached the surface. This resulted in the formation of various microstructural domains within the kelyphitic rims which were distinguished to three main types: fine-grained symplectites, recrystallized symplectites and cyrstallized melts. Fine-grained symplectites are the products of isochemical breakdown of garnet to pure anorthite, Al-orthopyroxene and hercynitic spinel. Nanoscale topography built up by curved chains of humps on the garnet surface showing regular spatial distribution is observed at the reaction front in 3D reconstructions. These patterns follow the contours of anorthites nucleating at the reaction front. This suggests that diffusion-controlled material transfer in solid state together with surface energy minimization determines symplectite microstructure. The latter leads to continuous isochemical coarsening getting further from the reaction front. Slight increase of Na and Ti-content in fine-grained symplectites is associated with sudden changes in 3D microstructure reflecting the effect of aquaeous fluids infiltrating to the reaction rim. A similar aquaeous fluid may have induced the formation of nearly isochemical melting and in situ recrystallization of the symplectites to form recrystallized symplectites. Some of these remained pristine, while some experienced ductile deformation and re-melting due to a reaction with an external melt in the lower crust. Well-crystallized melt pockets consisting of complexly zoned pyroxene, spinel and plagioclase grains were formed around 1000 ° C in this stage. Following this, interaction

  17. Imaging of 3D Ocean Turbulence Microstructure Using Low Frequency Acoustic Waves

    NASA Astrophysics Data System (ADS)

    Minakov, Alexander; Kolyukhin, Dmitriy; Keers, Henk

    2015-04-01

    In the past decade the technique of imaging the ocean structure with low-frequency signal (Hz), produced by air-guns and typically employed during conventional multichannel seismic data acquisition, has emerged. The method is based on extracting and stacking the acoustic energy back-scattered by the ocean temperature and salinity micro- and meso-structure (1 - 100 meters). However, a good understanding of the link between the scattered wavefield utilized by the seismic oceanography and physical processes in the ocean is still lacking. We describe theory and the numerical implementation of a 3D time-dependent stochastic model of ocean turbulence. The velocity and temperature are simulated as homogeneous Gaussian isotropic random fields with the Kolmogorov-Obukhov energy spectrum in the inertial subrange. Numerical modeling technique is employed for sampling of realizations of random fields with a given spatial-temporal spectral tensor. The model used is shown to be representative for a wide range of scales. Using this model, we provide a framework to solve the forward and inverse acoustic scattering problem using marine seismic data. Our full-waveform inversion method is based on the ray-Born approximation which is specifically suitable for the modelling of small velocity perturbations in the ocean. This is illustrated by showing a good match between synthetic seismograms computed using ray-Born and synthetic seismograms produced with a more computationally expensive finite-difference method.

  18. Improvements in Fabrication of 3D SU-8 Prisms for Low-Coupling-Loss Interconnections Between Fibers and Waveguides

    NASA Astrophysics Data System (ADS)

    Nguyen, Minh-Hang; Chu, Thi-Xuan; Nguyen, Long; Nguyen, Hai-Binh; Lee, Chun-Wei; Tseng, Fan-Gang; Chen, Te-Chang; Lee, Ming-Chang

    2016-07-01

    Fabrication of three-dimensional (3D) SU-8 (an epoxy-based negative photoresist from MicroChem) prisms as low-loss couplers for interconnection between optical components, particularly optical fibers and silicon-on-isolator waveguides (SOI WGs), which have mismatched mode sizes, has been investigated. With an interfacial structure formed by a 3D SU-8 prism partly overlaying an SOI WG end with a portion of buried oxide (BOX) removed under the interface, low-loss coupling is ensured and the transmission efficiency can reach 70%. To fabricate these 3D SU-8 prisms, a simple method with two photolithography steps was used for SU-8 hinges and CYTOP (an amorphous fluoropolymer from AGC Chemicals) prism windows, with mild soft and hard bakes, to define the prism profiles with diluted SU-8 filled in the CYTOP prism windows. A buffered oxide etchant is used to remove BOX parts under the interfaces. Some of the fabricated structures were tested, demonstrating the contribution of overlaying SU-8 prisms to the transmission efficiency of optical interconnections between fibers and SOI WGs.

  19. Microstructure of 3D-Printed Polymer Composites Investigated by Small-Angle Neutron Scattering

    NASA Astrophysics Data System (ADS)

    Kang, Tae Hui; Compton, Brett G.; Heller, William T.; Urban, Voker S.; Duty, Chad E.; Do, Changwoo

    Polymer composites printed from the large scale printer at Manufacturing Demonstration Facility at Oak Ridge National Laboratory have been investigated by small-angle neutron scattering (SANS). For the Acrylonitrile Butadiene Styrene (ABS)/Carbon Fiber (CF) composites, the microstructure of polymer domains and the alignment of CF have been characterized across the layer from the printed piece. CF shows strong anisotropic alignment along the printing direction due to the flow of polymer melt at the nozzle. Order parameter of the anisotropy which ranges from -0.11 to -0.06 exhibits strong correlation with the position within the layer: stronger alignment near the layer interface. It is also confirmed that the existence of CF reduces the polymer domain correlation length significantly and reinforces the mechanical strength of the polymer composites. For the Epoxy/nano-clay platelet composites, the effect of processing condition, nozzle size, and the addition of the another filler, Silicon Carbide (SC), have been investigated by SANS. Nano-clay platelet shows strong anisotropic alignment along the printing direction as well. Order parameter of the anisotropy varies according to nozzle size and presence of the SC, and difference disappears at high Q region. Scientific User Facilities Division and Materials Sciences and Energy Division, Office of Basic Energy Sciences, U.S. Department of Energy.

  20. Fabrication of freeform bone-filling calcium phosphate ceramics by gypsum 3D printing method.

    PubMed

    Lowmunkong, Rungnapa; Sohmura, Taiji; Suzuki, Yumiko; Matsuya, Shigeki; Ishikawa, Kunio

    2009-08-01

    Transformation of gypsum model fabricated by three-dimensional printing (3DP) into hydroxyapatite (HA) by treating in ammonium phosphate solution is possible. However, 3DP powder supplied by the manufacturer contains unknown additives which may be questionable for biomaterials. Accordingly, pure plaster of Paris (POP) powder was used for fabrication in the present study. For accurate fabrication, reduction of supplied binder ink to 80% of standard amount for 3DP powder supplied by the manufacturer was found to be the optimal condition for POP fabrication. Transformation from POP to HA was done by immersing into 1 mol/L ammonium phosphate solution. However, preheating of fabricated POP specimen at 200 degrees C for 30 min to change from calcium sulfate dihydrate into calcium sulfate hemihydrate could accelerate the transformation into HA effectively. To increase compressive strength, HA transformed specimen was sintering at 1150 degrees C for 3 h. The compressive strength increased four times comparing with as transformed HA specimen. However, crystal structure was transformed to beta-TCP due to the chemical reaction between the transformed HA and remained phosphate from ammonium phosphate solution at the sintering temperature. A sophisticated application of the present 3DP method to fabricate the freeform bioceramic for osseous defect was attempted, and jaw bone defect filling biomaterial of beta-TCP and scaffold with macroporous structures could be fabricated. Present 3DP method has possibility to fabricate freeform bioceramic for osseous defect or scaffold. PMID:19145633

  1. Fabrication of Single, Vertically Aligned Carbon Nanotubes in 3D Nanoscale Architectures

    NASA Technical Reports Server (NTRS)

    Kaul, Anupama B.; Megerian, Krikor G.; Von Allmen, Paul A.; Baron, Richard L.

    2010-01-01

    Plasma-enhanced chemical vapor deposition (PECVD) and high-throughput manufacturing techniques for integrating single, aligned carbon nanotubes (CNTs) into novel 3D nanoscale architectures have been developed. First, the PECVD growth technique ensures excellent alignment of the tubes, since the tubes align in the direction of the electric field in the plasma as they are growing. Second, the tubes generated with this technique are all metallic, so their chirality is predetermined, which is important for electronic applications. Third, a wafer-scale manufacturing process was developed that is high-throughput and low-cost, and yet enables the integration of just single, aligned tubes with nanoscale 3D architectures with unprecedented placement accuracy and does not rely on e-beam lithography. Such techniques should lend themselves to the integration of PECVD grown tubes for applications ranging from interconnects, nanoelectromechanical systems (NEMS), sensors, bioprobes, or other 3D electronic devices. Chemically amplified polyhydroxystyrene-resin-based deep UV resists were used in conjunction with excimer laser-based (lambda = 248 nm) step-and-repeat lithography to form Ni catalyst dots = 300 nm in diameter that nucleated single, vertically aligned tubes with high yield using dc PECVD growth. This is the first time such chemically amplified resists have been used, resulting in the nucleation of single, vertically aligned tubes. In addition, novel 3D nanoscale architectures have been created using topdown techniques that integrate single, vertically aligned tubes. These were enabled by implementing techniques that use deep-UV chemically amplified resists for small-feature-size resolution; optical lithography units that allow unprecedented control over layer-to-layer registration; and ICP (inductively coupled plasma) etching techniques that result in near-vertical, high-aspect-ratio, 3D nanoscale architectures, in conjunction with the use of materials that are

  2. Multi-scale Characterisation of the 3D Microstructure of a Thermally-Shocked Bulk Metallic Glass Matrix Composite.

    PubMed

    Zhang, Wei; Bodey, Andrew J; Sui, Tan; Kockelmann, Winfried; Rau, Christoph; Korsunsky, Alexander M; Mi, Jiawei

    2016-01-01

    Bulk metallic glass matrix composites (BMGMCs) are a new class of metal alloys which have significantly increased ductility and impact toughness, resulting from the ductile crystalline phases distributed uniformly within the amorphous matrix. However, the 3D structures and their morphologies of such composite at nano and micrometre scale have never been reported before. We have used high density electric currents to thermally shock a Zr-Ti based BMGMC to different temperatures, and used X-ray microtomography, FIB-SEM nanotomography and neutron diffraction to reveal the morphologies, compositions, volume fractions and thermal stabilities of the nano and microstructures. Understanding of these is essential for optimizing the design of BMGMCs and developing viable manufacturing methods. PMID:26725519

  3. Multi-scale Characterisation of the 3D Microstructure of a Thermally-Shocked Bulk Metallic Glass Matrix Composite

    PubMed Central

    Zhang, Wei; Bodey, Andrew J.; Sui, Tan; Kockelmann, Winfried; Rau, Christoph; Korsunsky, Alexander M.; Mi, Jiawei

    2016-01-01

    Bulk metallic glass matrix composites (BMGMCs) are a new class of metal alloys which have significantly increased ductility and impact toughness, resulting from the ductile crystalline phases distributed uniformly within the amorphous matrix. However, the 3D structures and their morphologies of such composite at nano and micrometre scale have never been reported before. We have used high density electric currents to thermally shock a Zr-Ti based BMGMC to different temperatures, and used X-ray microtomography, FIB-SEM nanotomography and neutron diffraction to reveal the morphologies, compositions, volume fractions and thermal stabilities of the nano and microstructures. Understanding of these is essential for optimizing the design of BMGMCs and developing viable manufacturing methods. PMID:26725519

  4. Physical properties and microstructures of nanocrystals reinforced ice laser 3D print layer

    NASA Astrophysics Data System (ADS)

    Li, Jia-Ning; Liu, Ke-Gao; Gong, Shui-Li; Zhang, Yuan-Bin; Liu, Peng

    2015-02-01

    Rapid prototyping based on laser alloying by the pre-placed mixed powders has been used to produce the nanocrystals reinforced three-dimensional layer in this study. Such a layer was fabricated on a TC17 titanium alloy by laser rapid prototyping (LRP) of the Co-Sb-TiB2 mixed powders in ice. Scanning electron microscope (SEM) and high resolution transmission electron microscopy (HRTEM) test results indicated that the ice addition was able to decrease the maximum temperature of molten pool during the LRP process, favoring the formation of nanocrystals; growth of such nanocrystals was retarded by the surrounded amorphous in a certain extent, favoring the formations of ultrafine nanoparticles (UN), and the twin crystals and the high-angle grain boundaries were also observed; differential thermal analysis (DTA) test was used to explain the physical properties and formation mechanism of amorphous-nanocrystals, and also the relationship between the amorphous and nanocrystalline phases in such a LRP layer.

  5. Fabrication and microstructure of Hg-1223 tape

    NASA Astrophysics Data System (ADS)

    Meng, R. L.; Wang, Y. Q.; Lewis, K.; Garcia, C.; Gao, L.; Xue, Y. Y.; Chu, C. W.

    1997-08-01

    A two-step spray/press process for the fabrication of Hg-1223 tape on a flexible Ni-substrate coated with Cr/(Ag,Pd) has been developed by using the mechanically aligned c-axis oriented Hg-1212 micrograins as the nucleation sites for the large c-axis oriented Hg-1223 grain growth. The self-field Jc of Hg-1223 tapes so reproducibly obtained is 7×104 A/cm2 at 77 K.

  6. High-resolution non-invasive 3D imaging of paint microstructure by synchrotron-based X-ray laminography

    NASA Astrophysics Data System (ADS)

    Reischig, Péter; Helfen, Lukas; Wallert, Arie; Baumbach, Tilo; Dik, Joris

    2013-06-01

    The characterisation of the microstructure and micromechanical behaviour of paint is key to a range of problems related to the conservation or technical art history of paintings. Synchrotron-based X-ray laminography is demonstrated in this paper to image the local sub-surface microstructure in paintings in a non-invasive and non-destructive way. Based on absorption and phase contrast, the method can provide high-resolution 3D maps of the paint stratigraphy, including the substrate, and visualise small features, such as pigment particles, voids, cracks, wood cells, canvas fibres etc. Reconstructions may be indicative of local density or chemical composition due to increased attenuation of X-rays by elements of higher atomic number. The paint layers and their interfaces can be distinguished via variations in morphology or composition. Results of feasibility tests on a painting mockup (oak panel, chalk ground, vermilion and lead white paint) are shown, where lateral and depth resolution of up to a few micrometres is demonstrated. The method is well adapted to study the temporal evolution of the stratigraphy in test specimens and offers an alternative to destructive sampling of original works of art.

  7. Fabrication of 3D Templates Using a Large Depth of Focus Femtosecond Laser

    NASA Astrophysics Data System (ADS)

    Li, Xiao-Fan; Winfield, Richard; O'Brien, Shane; Chen, Liang-Yao

    2009-09-01

    We report the use of a large depth of focus Bessel beam in the fabrication of cell structures. Two axicon lenses are investigated in the formation of high aspect ratio line structures. A sol-gel resin, with good mechanical strength, is polymerised in a modified two-photon polymerisation system. Examples of different two-dimensional grids are presented to show that the lateral resolution can be maintained even in the rapid fabrication of high-sided structures.

  8. Microplasma fabrication: from semiconductor technology for 2D-chips and microfluidic channels to rapid prototyping and 3D-printing of microplasma devices

    NASA Astrophysics Data System (ADS)

    Shatford, R.; Karanassios, Vassili

    2014-05-01

    Microplasmas are receiving attention in recent conferences and current scientific literature. In our laboratory, microplasmas-on-chips proved to be particularly attractive. The 2D- and 3D-chips we developed became hybrid because they were fitted with a quartz plate (quartz was used due to its transparency to UV). Fabrication of 2D- and 3D-chips for microplasma research is described. The fabrication methods described ranged from semiconductor fabrication technology, to Computer Numerical Control (CNC) machining, to 3D-printing. These methods may prove to be useful for those contemplating in entering microplasma research but have no access to expensive semiconductor fabrication equipment.

  9. Characterization of the first double-sided 3D radiation sensors fabricated at FBK on 6-inch silicon wafers

    NASA Astrophysics Data System (ADS)

    Sultan, D. M. S.; Mendicino, R.; Boscardin, M.; Ronchin, S.; Zorzi, N.; Dalla Betta, G.-F.

    2015-12-01

    Following 3D pixel sensor production for the ATLAS Insertable B-Layer, Fondazione Bruno Kessler (FBK) fabrication facility has recently been upgraded to process 6-inch wafers. In 2014, a test batch was fabricated to check for possible issues relevant to this upgrade. While maintaining a double-sided fabrication technology, some process modifications have been investigated. We report here on the technology and the design of this batch, and present selected results from the electrical characterization of sensors and test structures. Notably, the breakdown voltage is shown to exceed 200 V before irradiation, much higher than in earlier productions, demonstrating robustness in terms of radiation hardness for forthcoming productions aimed at High Luminosity LHC upgrades.

  10. High-throughput three-dimensional (3D) lithographic microfabrication in biomedical applications

    NASA Astrophysics Data System (ADS)

    Kim, Daekeun; So, Peter T. C.

    2010-02-01

    Two-photon excitation microfabrication has been shown to be useful in the field of photonics and biomedicine. It generates 3D microstructures and provides sub-diffraction fabrication resolution. Nevertheless, laser direct writing, the most popular two-photon fabrication technique, has slow fabrication speed, and its applications are limited to prototyping. In this proceeding, we propose high-throughput 3D lithographic microfabrication system based on depthresolved wide-field illumination and build several 3D microstructures with SU-8. Through these fabrications, 3D lithographic microfabrication has scalable function and high-throughput capability. It also has the potential for fabricating 3D microstructure in biomedical applications, such as intertwining channels in 3D microfluidic devices for biomedical analysis and 3D cell patterning in the tissue scaffolds.

  11. Microfluidic Fabrication of Bio-Inspired Microfibers with Controllable Magnetic Spindle-Knots for 3D Assembly and Water Collection.

    PubMed

    He, Xiao-Heng; Wang, Wei; Liu, Ying-Mei; Jiang, Ming-Yue; Wu, Fang; Deng, Ke; Liu, Zhuang; Ju, Xiao-Jie; Xie, Rui; Chu, Liang-Yin

    2015-08-12

    A simple and flexible approach is developed for controllable fabrication of spider-silk-like microfibers with tunable magnetic spindle-knots from biocompatible calcium alginate for controlled 3D assembly and water collection. Liquid jet templates with volatile oil drops containing magnetic Fe3O4 nanoparticles are generated from microfluidics for fabricating spider-silk-like microfibers. The structure of jet templates can be precisely adjusted by simply changing the flow rates to tailor the structures of the resultant spider-silk-like microfibers. The microfibers can be well manipulated by external magnetic fields for controllably moving, and patterning and assembling into different 2D and 3D structures. Moreover, the dehydrated spider-silk-like microfibers, with magnetic spindle-knots for collecting water drops, can be controllably assembled into spider-web-like structures for excellent water collection. These spider-silk-like microfibers are promising as functional building blocks for engineering complex 3D scaffolds for water collection, cell culture, and tissue engineering. PMID:26192108

  12. Meshing Preprocessor for the Mesoscopic 3D Finite Element Simulation of 2D and Interlock Fabric Deformation

    NASA Astrophysics Data System (ADS)

    Wendling, A.; Daniel, J. L.; Hivet, G.; Vidal-Sallé, E.; Boisse, P.

    2015-12-01

    Numerical simulation is a powerful tool to predict the mechanical behavior and the feasibility of composite parts. Among the available numerical approaches, as far as woven reinforced composites are concerned, 3D finite element simulation at the mesoscopic scale leads to a good compromise between realism and complexity. At this scale, the fibrous reinforcement is modeled by an interlacement of yarns assumed to be homogeneous that have to be accurately represented. Among the numerous issues induced by these simulations, the first one consists in providing a representative meshed geometrical model of the unit cell at the mesoscopic scale. The second one consists in enabling a fast data input in the finite element software (contacts definition, boundary conditions, elements reorientation, etc.) so as to obtain results within reasonable time. Based on parameterized 3D CAD modeling tool of unit-cells of dry fabrics already developed, this paper presents an efficient strategy which permits an automated meshing of the models with 3D hexahedral elements and to accelerate of several orders of magnitude the simulation data input. Finally, the overall modeling strategy is illustrated by examples of finite element simulation of the mechanical behavior of fabrics.

  13. Fabrication of 3D photocatalytic α-Fe2O3 structure using direct ink writing method

    NASA Astrophysics Data System (ADS)

    Li, Yayun; Li, Bo; Li, Longtu

    2014-02-01

    Three-dimensional (3D) photocatalytic devices are economical and environmental, since they can be easily recycled and reused. In this paper, a kind of 3D photocatalytic device with a rod diameter of 250 μm was fabricated using the aqueous-based α-Fe2O3 ceramic inks by direct ink writing (DIW) method. The properties of the DIW woodpile samples were investigated by X-ray diffraction (XRD), scanning electron microscope (SEM) and optical microscope. The result shows that the ink with solid content of 71.4 wt.% exhibits a shear thinning behavior and proper viscoelastic properties, which ensure a feasible extrusion in the whole shaping process. The sample sintered at 800°C in air causes photocatalytic degradation of methylene blue (MB) solution under the ultraviolet (UV) light. The photocatalytic properties of the α-Fe2O3 woodpile structure was characterized by the UV-visible light spectrophotometer, and it was found to be better than that of bulk sample with same weight for its higher specific surface. The DIW technique would offer a potential method for the design and fabrication of 3D photocatalytic devices.

  14. Spun-wrapped aligned nanofiber (SWAN) lithography for fabrication of micro/nano-structures on 3D objects

    NASA Astrophysics Data System (ADS)

    Ye, Zhou; Nain, Amrinder S.; Behkam, Bahareh

    2016-06-01

    Fabrication of micro/nano-structures on irregularly shaped substrates and three-dimensional (3D) objects is of significant interest in diverse technological fields. However, it remains a formidable challenge thwarted by limited adaptability of the state-of-the-art nanolithography techniques for nanofabrication on non-planar surfaces. In this work, we introduce Spun-Wrapped Aligned Nanofiber (SWAN) lithography, a versatile, scalable, and cost-effective technique for fabrication of multiscale (nano to microscale) structures on 3D objects without restriction on substrate material and geometry. SWAN lithography combines precise deposition of polymeric nanofiber masks, in aligned single or multilayer configurations, with well-controlled solvent vapor treatment and etching processes to enable high throughput (>10-7 m2 s-1) and large-area fabrication of sub-50 nm to several micron features with high pattern fidelity. Using this technique, we demonstrate whole-surface nanopatterning of bulk and thin film surfaces of cubes, cylinders, and hyperbola-shaped objects that would be difficult, if not impossible to achieve with existing methods. We demonstrate that the fabricated feature size (b) scales with the fiber mask diameter (D) as b1.5 ~ D. This scaling law is in excellent agreement with theoretical predictions using the Johnson, Kendall, and Roberts (JKR) contact theory, thus providing a rational design framework for fabrication of systems and devices that require precisely designed multiscale features.Fabrication of micro/nano-structures on irregularly shaped substrates and three-dimensional (3D) objects is of significant interest in diverse technological fields. However, it remains a formidable challenge thwarted by limited adaptability of the state-of-the-art nanolithography techniques for nanofabrication on non-planar surfaces. In this work, we introduce Spun-Wrapped Aligned Nanofiber (SWAN) lithography, a versatile, scalable, and cost-effective technique for

  15. Ship-in-a-bottle integration by hybrid femtosecond laser technology for fabrication of true 3D biochips

    NASA Astrophysics Data System (ADS)

    Sima, Felix; Wu, Dong; Xu, Jian; Midorikawa, Katsumi; Sugioka, Koji

    2015-03-01

    We propose herein the "ship-in-a-bottle" integration of three-dimensional (3D) polymeric sinusoidal ridges inside photosensitive glass microfluidic channel by a hybrid subtractive - additive femtosecond laser processing method. It consists of Femtosecond Laser Assisted Wet Etching (FLAE) of a photosensitive Foturan glass followed by Two-Photon Polymerization (TPP) of a SU-8 negative epoxy-resin. Both subtractive and additive processes are carried out using the same set-up with the change of laser focusing objective only. A 522 nm wavelength of the second harmonic generation from an amplified femtosecond Yb-fiber laser (FCPA µJewel D-400, IMRA America, 1045 nm; pulse width 360 fs, repetition rate 200 kHz) was employed for irradiation. The new method allows lowering the size limit of 3D objects created inside channels to smaller details down to the dimensions of a cell, and improve the structure stability. Sinusoidal periodic patterns and ridges are of great use as base scaffolds for building up new structures on their top or for modulating cell migration, guidance and orientation while created interspaces can be exploited for microfluidic applications. The glass microchannel offers robustness and appropriate dynamic flow conditions for cellular studies while the integrated patterns are reducing the size of structure to the level of cells responsiveness. Taking advantage of the ability to directly fabricate 3D complex shapes, both glass channels and polymeric integrated patterns enable us to 3D spatially design biochips for specific applications.

  16. Dielectrophoresis with 3D microelectrodes fabricated by surface tension assisted lithography.

    PubMed

    Nasabi, Mahyar; Khoshmanesh, Khashayar; Tovar-Lopez, Francisco J; Kalantar-Zadeh, Kourosh; Mitchell, Arnan

    2013-12-01

    This paper demonstrates the utilization of 3D semispherical shaped microelectrodes for dielectrophoretic manipulation of yeast cells. The semispherical microelectrodes are capable of producing strong electric field gradients, and in turn dielectrophoretic forces across a large area of channel cross-section. The semispherical shape of microelectrodes avoids the formation of undesired sharp electric fields along the structure and also minimizes the disturbance of the streamlines of nearby passing fluid. The advantage of semispherical microelectrodes over the planar microelectrodes is demonstrated in a series of numerical simulations and proof-of-concept experiments aimed toward immobilization of viable yeast cells. PMID:24347270

  17. Fabrication and Characterization of a Multichannel 3D Thermopile for Chip Calorimeter Applications

    PubMed Central

    Huynh, Tho Phuoc; Zhang, Yilei; Yehuda, Cohen

    2015-01-01

    Thermal sensors based on thermopiles are some of the most robust and popular temperature sensing technologies across industries and research disciplines. A chip calorimeter with a 3D thermopile layout with a large sensing area and multichannel capacity has been developed, which is highly desired for many applications requiring large reaction chambers or high throughputs, such as biofilm research, drug screening, etc. The performance of the device, including temperature sensitivity and heat power sensitivity, was evaluated. The capability to split the chip calorimeter to multiple channels was also demonstrated, which makes the chip calorimeter very flexible and powerful in many applications. PMID:25654716

  18. Novel and simple route to fabricate 2D ordered gold nanobowl arrays based on 3D colloidal crystals.

    PubMed

    Rao, Yanying; Tao, Qin; An, Ming; Rong, Chunhui; Dong, Jian; Dai, Yurong; Qian, Weiping

    2011-11-01

    In this study, we present a new method to fabricate large-area two-dimensionally (2D) ordered gold nanobowl arrays based on 3D colloidal crystals by wet chemosynthesis, which combines the advantages of a very simple preparation and an applicability to "real" nanomaterials. By combination of in situ growth of gold nanoshell (GNSs) arrays based on three-dimensional (3D) colloidal silica crystals, a monolayer ordered reversed GNS array (2D ordered GNS array) was conveniently manufactured by an acrylic ester modified biaxial oriented polypropylene (BOPP). 2D ordered gold nanobowl array with adjustable periodic holes, good stability, reproducibility, and repeatability could be obtained when the silica core was etched by HF solution. The surface-enhanced Raman scattering (SERS) enhancement factor (EF) of this 2D ordered gold nanobowl array could reach 1.27 × 10(7), which shows high SERS enhancing activity and can be used as a universal SERS substrate. PMID:21932785

  19. Fabrication of chitosan-silver nanoparticle hybrid 3D porous structure as a SERS substrate for biomedical applications

    NASA Astrophysics Data System (ADS)

    Jung, Gyeong-Bok; Kim, Ji-Hye; Burm, Jin Sik; Park, Hun-Kuk

    2013-05-01

    We propose a simple, low-cost, large-area, and functional surface enhanced Raman scattering (SERS) substrate for biomedical applications. The SERS substrate with chitosan-silver nanoparticles (chitosan-Ag NPs) hybrid 3D porous structure was fabricated simply by a one-step method. The chitosan was used as a template for the Ag NPs deposition. SERS enhancement by the chitosan-Ag NPs substrate was experimentally verified using rhodamine B as an analyte. Thiolated single stranded DNA was also measured for atopic dermatitis genetic markers (chemokines CCL17) at a low concentration of 5 pM. We successfully designed a novel SERS substrate with silver nanoparticle hybridized 3D porous chitosan that has the potential to become a highly sensitive and selective tool for biomedical applications.

  20. 3D nanoimprint for NIR Fabry-Pérot filter arrays: fabrication, characterization and comparison of different cavity designs

    NASA Astrophysics Data System (ADS)

    Nguyen, Duc Toan; Ababtain, Muath; Memon, Imran; Ullah, Anayat; Istock, André; Woidt, Carsten; Xie, Weichang; Lehmann, Peter; Hillmer, Hartmut

    2016-02-01

    We report on the fabrication of miniaturized NIR spectrometers based on arrays of multiple Fabry-Pérot (FP) filters. The various cavities of different height are fabricated via a single patterning step using high resolution 3D nanoimprint technology. Today, low-cost patterning of extended cavity heights for NIR filters using the conventional spin-coated nanoimprint methodology is not available because of insufficient coating layers and low mobility of the resist materials to fill extended cavity structures. Our investigation focuses on reducing the technological effort for fabrication of homogeneous extended cavities. We study alternative cavity designs, including a new resist and apply large-area 3D nanoimprint based on hybrid mold and UV Substrate Conformal Imprint Lithography (UV-SCIL) to overcome these limitations. We compare three different solutions, i.e. (1) applying multiple spin coating of the resist to obtain thicker initial resist layers, (2) introducing a hybrid cavity (combination of a thin oxide layer and the organic cavity) to compensate the height differences, and (3) optimizing the imprint process with a novel resist material. The imprint results based on these methods demonstrate the implementation of NIR FP filters with high transmission intensity (best single filter transmission >90 %) and small line widths (<5 nm in full width at half maximum).

  1. Design and fabrication of cast orthopedic implants with freeform surface textures from 3-D printed ceramic shell.

    PubMed

    Curodeau, A; Sachs, E; Caldarise, S

    2000-09-01

    Three-dimensional printing is a solid freeform fabrication process, which creates parts directly from a computer model. The parts are built by repetitively spreading a layer of powder and selectively joining the powder in the layer by ink-jet printing of a binder material. 3D printing was applied to the fabrication of sub-millimeter surface textures with overhang and undercut geometries for use in orthopedic prostheses as bony ingrowth structures. 3D printing is used to fabricate ceramic molds of alumina powder and silica binder, and these molds are used to cast the bony ingrowth surfaces of Co-Cr (ASTM F75) alloy. Minimum positive feature sizes of the ceramic mold and, therefore, minimum negative feature sizes of castings were determined to be approximately 200 x 200 x 175 microm and were limited by the strength of ceramic needed to withstand handling. Minimum negative feature sizes in the ceramic mold and, therefore, minimum positive features in the casting were found to be approximately 350 x 350 x 175 microm and were determined by limitations on removal of powder from the ceramic and the pressure required to fill these small features with molten metal during casting. Textures were designed with 5 layers of distinct geometric definition, allowing for the design of overhung geometry with overall porosity ranging from 30-70%. Features as small as 350 x 350 x 200 microm were included in these designs and successfully cast. PMID:10984701

  2. Fabrication of a 3D active mixer based on deformable Fe-doped PDMS cones with magnetic actuation

    NASA Astrophysics Data System (ADS)

    Riahi, Mohammadreza; Alizadeh, Elaheh

    2012-11-01

    In this paper an active 3D mixer for lab-on-chip applications is presented. The micrometer size cone shape holes are ablated on a PMMA sheet utilizing a CO2 laser. The holes are filled with Fe micro-particles and the whole structure is molded with PDMS which cause the Fe micro-particles to be trapped in a PDMS cone structure. These Fe-doped PDMS cones are placed in a PMMA micro-channel structure fabricated by CO2 laser machining. By applying an external periodic magnetic field, the cones periodically bend in the micro-channel and stir the fluid. The fabrication method and the effect of the magnetic field on the bending of the cones with different aspect ratios is also discussed utilizing computer simulation. Doping the polymers with micro- and nano-metallic particles has been carried out by different research groups before, but according to our knowledge, application of such structures for the fabrication of a 3D active mixer has not been presented before.

  3. 3D Imaging with a Single-Aperture 3-mm Objective Lens: Concept, Fabrication and Test

    NASA Technical Reports Server (NTRS)

    Korniski, Ron; Bae, Sam Y.; Shearn, Mike; Manohara, Harish; Shahinian, Hrayr

    2011-01-01

    There are many advantages to minimally invasive surgery (MIS). An endoscope is the optical system of choice by the surgeon for MIS. The smaller the incision or opening made to perform the surgery, the smaller the optical system needed. For minimally invasive neurological and skull base surgeries the openings are typically 10-mm in diameter (dime sized) or less. The largest outside diameter (OD) endoscope used is 4mm. A significant drawback to endoscopic MIS is that it only provides a monocular view of the surgical site thereby lacking depth information for the surgeon. A stereo view would provide the surgeon instantaneous depth information of the surroundings within the field of view, a significant advantage especially during brain surgery. Providing 3D imaging in an endoscopic objective lens system presents significant challenges because of the tight packaging constraints. This paper presents a promising new technique for endoscopic 3D imaging that uses a single lens system with complementary multi-bandpass filters (CMBFs), and describes the proof-of-concept demonstrations performed to date validating the technique. These demonstrations of the technique have utilized many commercial off-the-shelf (COTS) components including the ones used in the endoscope objective.

  4. Fabrication and characterization of gels with integrated channels using 3D printing with microfluidic nozzle for tissue engineering applications.

    PubMed

    Attalla, R; Ling, C; Selvaganapathy, P

    2016-02-01

    The lack of a simple and effective method to integrate vascular network with engineered scaffolds and tissue constructs remains one of the biggest challenges in true 3D tissue engineering. Here, we detail the use of a commercially available, low-cost, open-source 3D printer modified with a microfluidic print-head in order to develop a method for the generation of instantly perfusable vascular network integrated with gel scaffolds seeded with cells. The print-head features an integrated coaxial nozzle that allows the fabrication of hollow, calcium-polymerized alginate tubes that can be easily patterned using 3D printing techniques. The diameter of the hollow channel can be precisely controlled and varied between 500 μm - 2 mm by changing applied flow rates or print-head speed. These channels are integrated into gel layers with a thickness of 800 μm - 2.5 mm. The structural rigidity of these constructs allows the fabrication of multi-layered structures without causing the collapse of hollow channels in lower layers. The 3D printing method was fully characterized at a range of operating speeds (0-40 m/min) and corresponding flow rates (1-30 mL/min) were identified to produce precise definition. This microfluidic design also allows the incorporation of a wide range of scaffold materials as well as biological constituents such as cells, growth factors, and ECM material. Media perfusion of the channels causes a significant viability increase in the bulk of cell-laden structures over the long-term. With this setup, gel constructs with embedded arrays of hollow channels can be created and used as a potential substitute for blood vessel networks. PMID:26842949

  5. Coated U(Mo) Fuel: As-Fabricated Microstructures

    SciTech Connect

    Emmanuel Perez; Dennis D. Keiser, Jr.; Ann Leenaers; Sven Van den Berghe; Tom Wiencek

    2014-04-01

    As part of the development of low-enriched uranium fuels, fuel plates have recently been tested in the BR-2 reactor as part of the SELENIUM experiment. These fuel plates contained fuel particles with either Si or ZrN thin film coating (up to 1 µm thickness) around the U-7Mo fuel particles. In order to best understand irradiation performance, it is important to determine the starting microstructure that can be observed in as-fabricated fuel plates. To this end, detailed microstructural characterization was performed on ZrN and Si-coated U-7Mo powder in samples taken from AA6061-clad fuel plates fabricated at 500°C. Of interest was the condition of the thin film coatings after fabrication at a relatively high temperature. Both scanning electron microscopy and transmission electron microscopy were employed. The ZrN thin film coating was observed to consist of columns comprised of very fine ZrN grains. Relatively large amounts of porosity could be found in some areas of the thin film, along with an enrichment of oxygen around each of the the ZrN columns. In the case of the pure Si thin film coating sample, a (U,Mo,Al,Si) interaction layer was observed around the U-7Mo particles. Apparently, the Si reacted with the U-7Mo and Al matrix during fuel plate fabrication at 500°C to form this layer. The microstructure of the formed layer is very similar to those that form in U-7Mo versus Al-Si alloy diffusion couples annealed at higher temperatures and as-fabricated U-7Mo dispersion fuel plates with Al-Si alloy matrix fabricated at 500°C.

  6. A fabrication method of microneedle molds with controlled microstructures.

    PubMed

    Wang, Qi Lei; Zhu, Dan Dan; Chen, Yang; Guo, Xin Dong

    2016-08-01

    Microneedle (MN) offers an attractive, painless and minimally invasive approach for transdermal drug delivery. Polymer microneedles are normally fabricated by using the micromolding method employing a MN mold, which is suitable for mass production due to high production efficiency and repeat-using of the mold. Most of the MN molds are prepared by pouring sylgard polymer over a MN master to make an inverse one after curing, which is limited in optimizing or controlling the MN structures and failing to keep the sharpness of MNs. In this work we describe a fabrication method of MN mold with controlled microstructures, which is meaningful for the fabrication of polymer MNs with different geometries. Laser micro-machining method was employed to drill on the surface of PDMS sheets to obtain MN molds. In the fabrication process, the microstructures of MN molds are precisely controlled by changing laser parameters and imported patterns. The MNs prepared from these molds are sharp enough to penetrate the skin. This scalable MN mold fabrication method is helpful for future applications of MNs. PMID:27157736

  7. Design and fabrication of 3D-printed anatomically shaped lumbar cage for intervertebral disc (IVD) degeneration treatment.

    PubMed

    Serra, T; Capelli, C; Toumpaniari, R; Orriss, I R; Leong, J J H; Dalgarno, K; Kalaskar, D M

    2016-01-01

    Spinal fusion is the gold standard surgical procedure for degenerative spinal conditions when conservative therapies have been unsuccessful in rehabilitation of patients. Novel strategies are required to improve biocompatibility and osseointegration of traditionally used materials for lumbar cages. Furthermore, new design and technologies are needed to bridge the gap due to the shortage of optimal implant sizes to fill the intervertebral disc defect. Within this context, additive manufacturing technology presents an excellent opportunity to fabricate ergonomic shape medical implants. The goal of this study is to design and manufacture a 3D-printed lumbar cage for lumbar interbody fusion. Optimisations of the proposed implant design and its printing parameters were achieved via in silico analysis. The final construct was characterised via scanning electron microscopy, contact angle, x-ray micro computed tomography (μCT), atomic force microscopy, and compressive test. Preliminary in vitro cell culture tests such as morphological assessment and metabolic activities were performed to access biocompatibility of 3D-printed constructs. Results of in silico analysis provided a useful platform to test preliminary cage design and to find an optimal value of filling density for 3D printing process. Surface characterisation confirmed a uniform coating of nHAp with nanoscale topography. Mechanical evaluation showed mechanical properties of final cage design similar to that of trabecular bone. Preliminary cell culture results showed promising results in terms of cell growth and activity confirming biocompatibility of constructs. Thus for the first time, design optimisation based on computational and experimental analysis combined with the 3D-printing technique for intervertebral fusion cage has been reported in a single study. 3D-printing is a promising technique for medical applications and this study paves the way for future development of customised implants in spinal

  8. Fabrication of 3-D Photonic Band Gap Crystals Via Colloidal Self-Assembly

    NASA Technical Reports Server (NTRS)

    Subramaniam, Girija; Blank, Shannon

    2005-01-01

    The behavior of photons in a Photonic Crystals, PCs, is like that of electrons in a semiconductor in that, it prohibits light propagation over a band of frequencies, called Photonic Band Gap, PBG. Photons cannot exist in these band gaps like the forbidden bands of electrons. Thus, PCs lend themselves as potential candidates for devices based on the gap phenomenon. The popular research on PCs stem from their ability to confine light with minimal losses. Large scale 3-D PCs with a PBG in the visible or near infra red region will make optical transistors and sharp bent optical fibers. Efforts are directed to use PCs for information processing and it is not long before we can have optical integrated circuits in the place of electronic ones.

  9. Challenges and limitations of patient-specific vascular phantom fabrication using 3D Polyjet printing

    NASA Astrophysics Data System (ADS)

    Ionita, Ciprian N.; Mokin, Maxim; Varble, Nicole; Bednarek, Daniel R.; Xiang, Jianping; Snyder, Kenneth V.; Siddiqui, Adnan H.; Levy, Elad I.; Meng, Hui; Rudin, Stephen

    2014-03-01

    Additive manufacturing (3D printing) technology offers a great opportunity towards development of patient-specific vascular anatomic models, for medical device testing and physiological condition evaluation. However, the development process is not yet well established and there are various limitations depending on the printing materials, the technology and the printer resolution. Patient-specific neuro-vascular anatomy was acquired from computed tomography angiography and rotational digital subtraction angiography (DSA). The volumes were imported into a Vitrea 3D workstation (Vital Images Inc.) and the vascular lumen of various vessels and pathologies were segmented using a "marching cubes" algorithm. The results were exported as Stereo Lithographic (STL) files and were further processed by smoothing, trimming, and wall extrusion (to add a custom wall to the model). The models were printed using a Polyjet printer, Eden 260V (Objet-Stratasys). To verify the phantom geometry accuracy, the phantom was reimaged using rotational DSA, and the new data was compared with the initial patient data. The most challenging part of the phantom manufacturing was removal of support material. This aspect could be a serious hurdle in building very tortuous phantoms or small vessels. The accuracy of the printed models was very good: distance analysis showed average differences of 120 μm between the patient and the phantom reconstructed volume dimensions. Most errors were due to residual support material left in the lumen of the phantom. Despite the post-printing challenges experienced during the support cleaning, this technology could be a tremendous benefit to medical research such as in device development and testing.

  10. Challenges and limitations of patient-specific vascular phantom fabrication using 3D Polyjet printing

    PubMed Central

    Ionita, Ciprian N; Mokin, Maxim; Varble, Nicole; Bednarek, Daniel R; Xiang, Jianping; Snyder, Kenneth V; Siddiqui, Adnan H; Levy, Elad I; Meng, Hui; Rudin, Stephen

    2014-01-01

    Additive manufacturing (3D printing) technology offers a great opportunity towards development of patient-specific vascular anatomic models, for medical device testing and physiological condition evaluation. However, the development process is not yet well established and there are various limitations depending on the printing materials, the technology and the printer resolution. Patient-specific neuro-vascular anatomy was acquired from computed tomography angiography and rotational digital subtraction angiography (DSA). The volumes were imported into a Vitrea 3D workstation (Vital Images Inc.) and the vascular lumen of various vessels and pathologies were segmented using a “marching cubes” algorithm. The results were exported as Stereo Lithographic (STL) files and were further processed by smoothing, trimming, and wall extrusion (to add a custom wall to the model). The models were printed using a Polyjet printer, Eden 260V (Objet-Stratasys). To verify the phantom geometry accuracy, the phantom was reimaged using rotational DSA, and the new data was compared with the initial patient data. The most challenging part of the phantom manufacturing was removal of support material. This aspect could be a serious hurdle in building very tortuous phantoms or small vessels. The accuracy of the printed models was very good: distance analysis showed average differences of 120 μm between the patient and the phantom reconstructed volume dimensions. Most errors were due to residual support material left in the lumen of the phantom. Despite the post-printing challenges experienced during the support cleaning, this technology could be a tremendous benefit to medical research such as in device development and testing. PMID:25300886

  11. Inverted Yablonovite-like 3D photonic crystals fabricated by laser nanolithography

    NASA Astrophysics Data System (ADS)

    Shishkin, Ivan I.; Samusev, Kirill B.; Rybin, Mikhail V.; Limonov, Mikhail F.; Kivshar, Yuri S.; Gaidukeviciute, Arune; Kiyan, Roman V.; Chichkov, Boris N.

    2012-06-01

    We report on the fabrication of inverted Yablonovite-like three-dimensional photonic crystals by nonlinear optical nanolithography based on two-photon polymerization of a zirconium propoxide hybrid organic-inorganic material with Irgacure 369 as photo-initiator. Advantage of this material is ultra-low shrinkage that guaranty high fabrication fidelity. Images of the fabricated structure are obtained with a scanning electron microscope. The photonic crystal consists of three sets of nearly cylindrical structural elements directed along the three lattice vectors of the fcc lattice and cross each other at certain angles to produce inverted Yablonovite geometry. To investigate photonic properties of the inverted Yablonovite structures, we calculate the photonic band structure for ten lowest-frequency electromagnetic modes. In contrast to the direct Yablonovite structure that has a complete photonic band gap between the second and third bands, we find no complete photonic band gaps in the inverted Yablonovite lattice. This situation is opposite to the case of fcc lattice of close-packed dielectric spheres in air that has a complete photonic band gap only for the inverted geometry.

  12. Engineered cardiac micromodules for the in vitro fabrication of 3D endogenous macro-tissues.

    PubMed

    Totaro, A; Urciuolo, F; Imparato, G; Netti, P A

    2016-01-01

    The in vitro fabrication of an endogenous cardiac muscle would have a high impact for both in vitro studies concerning cardiac tissue physiology and pathology, as well as in vivo application to potentially repair infarcted myocardium. To reach this aim, we engineered a new class of cardiac tissue precursor (CTP), specifically conceived in order to promote the synthesis and the assembly of a cardiac extracellular matrix (ECM). The CTPs were obtained by culturing a mixed cardiac cell population, composed of myocyte and non-myocyte cells, into porous gelatin microspheres in a dynamic bioreactor. By engineering the culture conditions, the CTP developed both beating properties and an endogenous immature cardiac ECM. By following a bottom-up approach, a macrotissue was fabricated by molding and packing the engineered tissue precursor in a maturation chamber. During the macrotissue formation, the tissue precursors acted as cardiac tissue depots by promoting the formation of an endogenous and interconnected cardiac network embedding the cells and the microbeads. The myocytes cell fraction pulled on ECM network and induced its compaction against the internal posts represented by the initial porous microbeads. This reciprocal interplay induced ECM consolidation without the use of external biophysical stimuli by leading to the formation of a beating and endogenous macrotissue. We have thus engineered a new class of cardiac micromodules and show its potential for the fabrication of endogenous cardiac tissue models useful for in vitro studies that involve the cardiac tissue remodeling. PMID:27213995

  13. 3D printing in X-ray and Gamma-Ray Imaging: A novel method for fabricating high-density imaging apertures☆

    PubMed Central

    Miller, Brian W.; Moore, Jared W.; Barrett, Harrison H.; Fryé, Teresa; Adler, Steven; Sery, Joe; Furenlid, Lars R.

    2011-01-01

    Advances in 3D rapid-prototyping printers, 3D modeling software, and casting techniques allow for cost-effective fabrication of custom components in gamma-ray and X-ray imaging systems. Applications extend to new fabrication methods for custom collimators, pinholes, calibration and resolution phantoms, mounting and shielding components, and imaging apertures. Details of the fabrication process for these components, specifically the 3D printing process, cold casting with a tungsten epoxy, and lost-wax casting in platinum are presented. PMID:22199414

  14. Photolithographic fabrication of 3D Penrose-like quasi-photonic crystal polymeric templates utilizing lab-made phasemask

    NASA Astrophysics Data System (ADS)

    Torres-Lazos, Faraon

    Photonic crystals (PhC) have recently become of great interest because of their potential as replacement of electronics and/or supplement to semiconductors technology. The PhC's capability to make compact integrated optical circuits has already made possible the laboratory manufacture of an array of different types of optical waveguides, cavities and filters. The work presented here aimed to simultaneously fabricate a 3D-PhC templates employing six-beam holographic lithography. The basic procedures included recording gratings using interference field of laser sources in a photoresist coating on a glass substrate. The manufacturing method utilized only one optical element, a phasemask, drastically reducing the complexity of fabrication by eliminating the need multiple mirrors and beam splitters. Using this approach, a template can be created with a single exposure to laser source and just varying exposure times, increasing reproducibility.

  15. Fabrication of 3D copper oxide structure by holographic lithography for photoelectrochemical electrodes.

    PubMed

    Jin, Woo-Min; Kang, Ji-Hwan; Moon, Jun Hyuk

    2010-11-01

    We fabricated three-dimensional copper oxide structure by holographic lithography and electroless deposition. A five-beam interference pattern defined a woodpile structure of SU-8. The surface modification of SU-8 structure was achieved by multilayer coating of polyelectrolyte, which is critical for activating the surface for the reduction of copper. Copper was deposited onto the surface of the structure by electroless deposition, and subsequent calcinations removed the SU-8 structure and simultaneously oxidized the copper into copper oxide. The porous copper oxide structure was used as a photoelectrochemical electrode. Because of the highly porous structure, our structure showed higher photocurrent efficiency. PMID:21062017

  16. Direct fabrication of 3D graphene on nanoporous anodic alumina by plasma-enhanced chemical vapor deposition

    NASA Astrophysics Data System (ADS)

    Zhan, Hualin; Garrett, David J.; Apollo, Nicholas V.; Ganesan, Kumaravelu; Lau, Desmond; Prawer, Steven; Cervenka, Jiri

    2016-01-01

    High surface area electrode materials are of interest for a wide range of potential applications such as super-capacitors and electrochemical cells. This paper describes a fabrication method of three-dimensional (3D) graphene conformally coated on nanoporous insulating substrate with uniform nanopore size. 3D graphene films were formed by controlled graphitization of diamond-like amorphous carbon precursor films, deposited by plasma-enhanced chemical vapour deposition (PECVD). Plasma-assisted graphitization was found to produce better quality graphene than a simple thermal graphitization process. The resulting 3D graphene/amorphous carbon/alumina structure has a very high surface area, good electrical conductivity and exhibits excellent chemically stability, providing a good material platform for electrochemical applications. Consequently very large electrochemical capacitance values, as high as 2.1 mF for a sample of 10 mm3, were achieved. The electrochemical capacitance of the material exhibits a dependence on bias voltage, a phenomenon observed by other groups when studying graphene quantum capacitance. The plasma-assisted graphitization, which dominates the graphitization process, is analyzed and discussed in detail.

  17. Direct fabrication of 3D graphene on nanoporous anodic alumina by plasma-enhanced chemical vapor deposition.

    PubMed

    Zhan, Hualin; Garrett, David J; Apollo, Nicholas V; Ganesan, Kumaravelu; Lau, Desmond; Prawer, Steven; Cervenka, Jiri

    2016-01-01

    High surface area electrode materials are of interest for a wide range of potential applications such as super-capacitors and electrochemical cells. This paper describes a fabrication method of three-dimensional (3D) graphene conformally coated on nanoporous insulating substrate with uniform nanopore size. 3D graphene films were formed by controlled graphitization of diamond-like amorphous carbon precursor films, deposited by plasma-enhanced chemical vapour deposition (PECVD). Plasma-assisted graphitization was found to produce better quality graphene than a simple thermal graphitization process. The resulting 3D graphene/amorphous carbon/alumina structure has a very high surface area, good electrical conductivity and exhibits excellent chemically stability, providing a good material platform for electrochemical applications. Consequently very large electrochemical capacitance values, as high as 2.1 mF for a sample of 10 mm(3), were achieved. The electrochemical capacitance of the material exhibits a dependence on bias voltage, a phenomenon observed by other groups when studying graphene quantum capacitance. The plasma-assisted graphitization, which dominates the graphitization process, is analyzed and discussed in detail. PMID:26805546

  18. Direct fabrication of 3D graphene on nanoporous anodic alumina by plasma-enhanced chemical vapor deposition

    PubMed Central

    Zhan, Hualin; Garrett, David J.; Apollo, Nicholas V.; Ganesan, Kumaravelu; Lau, Desmond; Prawer, Steven; Cervenka, Jiri

    2016-01-01

    High surface area electrode materials are of interest for a wide range of potential applications such as super-capacitors and electrochemical cells. This paper describes a fabrication method of three-dimensional (3D) graphene conformally coated on nanoporous insulating substrate with uniform nanopore size. 3D graphene films were formed by controlled graphitization of diamond-like amorphous carbon precursor films, deposited by plasma-enhanced chemical vapour deposition (PECVD). Plasma-assisted graphitization was found to produce better quality graphene than a simple thermal graphitization process. The resulting 3D graphene/amorphous carbon/alumina structure has a very high surface area, good electrical conductivity and exhibits excellent chemically stability, providing a good material platform for electrochemical applications. Consequently very large electrochemical capacitance values, as high as 2.1 mF for a sample of 10 mm3, were achieved. The electrochemical capacitance of the material exhibits a dependence on bias voltage, a phenomenon observed by other groups when studying graphene quantum capacitance. The plasma-assisted graphitization, which dominates the graphitization process, is analyzed and discussed in detail. PMID:26805546

  19. Design and fabrication of concave-convex lens for head mounted virtual reality 3D glasses

    NASA Astrophysics Data System (ADS)

    Deng, Zhaoyang; Cheng, Dewen; Hu, Yuan; Huang, Yifan; Wang, Yongtian

    2015-08-01

    As a kind of light-weighted and convenient tool to achieve stereoscopic vision, virtual reality glasses are gaining more popularity nowadays. For these glasses, molded plastic lenses are often adopted to handle both the imaging property and the cost of massive production. However, the as-built performance of the glass depends on both the optical design and the injection molding process, and maintaining the profile of the lens during injection molding process presents particular challenges. In this paper, optical design is combined with processing simulation analysis to obtain a design result suitable for injection molding. Based on the design and analysis results, different experiments are done using high-quality equipment to optimize the process parameters of injection molding. Finally, a single concave-convex lens is designed with a field-of-view of 90° for the virtual reality 3D glasses. The as-built profile error of the glass lens is controlled within 5μm, which indicates that the designed shape of the lens is fairly realized and the designed optical performance can thus be achieved.

  20. Fabrication of fully undercut ZnO-based photonic crystal membranes with 3D optical confinement

    NASA Astrophysics Data System (ADS)

    Hoffmann, Sandro Phil; Albert, Maximilian; Meier, Cedrik

    2016-09-01

    For studying nonlinear photonics, a highly controllable emission of photons with specific properties is essential. Two-dimensional photonic crystals (PhCs) have proven to be an excellent candidate for manipulating photon emission due to resonator-based effects. Additionally, zinc oxide (ZnO) has high susceptibility coefficients and therefore shows pronounced nonlinear effects. However, in order to fabricate such a cavity, a fully undercut ZnO membrane is required, which is a challenging problem due to poor selectivity of the known etching chemistry for typical substrates such as sapphire or ZnO. The aim of this paper is to demonstrate and characterize fully undercut photonic crystal membranes based on a thin ZnO film sandwiched between two layers of silicon dioxide (SiO2) on silicon substrates, from the initial growth of the heterostructure throughout the entire fabrication process. This process leads to a fully undercut ZnO-based membrane with adjustable optical confinement in all three dimensions. Finally, photonic resonances within the tailored photonic band gap are achieved due to optimized PhC-design (in-plane) and total internal reflection in the z-direction. The presented approach enables a variety of photon based resonator structures in the UV regime for studying nonlinear effects, including photon-exciton coupling and all-optical switching.

  1. Real-time microstructure imaging by Laue microdiffraction: A sample application in laser 3D printed Ni-based superalloys

    NASA Astrophysics Data System (ADS)

    Zhou, Guangni; Zhu, Wenxin; Shen, Hao; Li, Yao; Zhang, Anfeng; Tamura, Nobumichi; Chen, Kai

    2016-06-01

    Synchrotron-based Laue microdiffraction has been widely applied to characterize the local crystal structure, orientation, and defects of inhomogeneous polycrystalline solids by raster scanning them under a micro/nano focused polychromatic X-ray probe. In a typical experiment, a large number of Laue diffraction patterns are collected, requiring novel data reduction and analysis approaches, especially for researchers who do not have access to fast parallel computing capabilities. In this article, a novel approach is developed by plotting the distributions of the average recorded intensity and the average filtered intensity of the Laue patterns. Visualization of the characteristic microstructural features is realized in real time during data collection. As an example, this method is applied to image key features such as microcracks, carbides, heat affected zone, and dendrites in a laser assisted 3D printed Ni-based superalloy, at a speed much faster than data collection. Such analytical approach remains valid for a wide range of crystalline solids, and therefore extends the application range of the Laue microdiffraction technique to problems where real-time decision-making during experiment is crucial (for instance time-resolved non-reversible experiments).

  2. Real-time microstructure imaging by Laue microdiffraction: A sample application in laser 3D printed Ni-based superalloys

    PubMed Central

    Zhou, Guangni; Zhu, Wenxin; Shen, Hao; Li, Yao; Zhang, Anfeng; Tamura, Nobumichi; Chen, Kai

    2016-01-01

    Synchrotron-based Laue microdiffraction has been widely applied to characterize the local crystal structure, orientation, and defects of inhomogeneous polycrystalline solids by raster scanning them under a micro/nano focused polychromatic X-ray probe. In a typical experiment, a large number of Laue diffraction patterns are collected, requiring novel data reduction and analysis approaches, especially for researchers who do not have access to fast parallel computing capabilities. In this article, a novel approach is developed by plotting the distributions of the average recorded intensity and the average filtered intensity of the Laue patterns. Visualization of the characteristic microstructural features is realized in real time during data collection. As an example, this method is applied to image key features such as microcracks, carbides, heat affected zone, and dendrites in a laser assisted 3D printed Ni-based superalloy, at a speed much faster than data collection. Such analytical approach remains valid for a wide range of crystalline solids, and therefore extends the application range of the Laue microdiffraction technique to problems where real-time decision-making during experiment is crucial (for instance time-resolved non-reversible experiments). PMID:27302087

  3. Real-time microstructure imaging by Laue microdiffraction: A sample application in laser 3D printed Ni-based superalloys.

    PubMed

    Zhou, Guangni; Zhu, Wenxin; Shen, Hao; Li, Yao; Zhang, Anfeng; Tamura, Nobumichi; Chen, Kai

    2016-01-01

    Synchrotron-based Laue microdiffraction has been widely applied to characterize the local crystal structure, orientation, and defects of inhomogeneous polycrystalline solids by raster scanning them under a micro/nano focused polychromatic X-ray probe. In a typical experiment, a large number of Laue diffraction patterns are collected, requiring novel data reduction and analysis approaches, especially for researchers who do not have access to fast parallel computing capabilities. In this article, a novel approach is developed by plotting the distributions of the average recorded intensity and the average filtered intensity of the Laue patterns. Visualization of the characteristic microstructural features is realized in real time during data collection. As an example, this method is applied to image key features such as microcracks, carbides, heat affected zone, and dendrites in a laser assisted 3D printed Ni-based superalloy, at a speed much faster than data collection. Such analytical approach remains valid for a wide range of crystalline solids, and therefore extends the application range of the Laue microdiffraction technique to problems where real-time decision-making during experiment is crucial (for instance time-resolved non-reversible experiments). PMID:27302087

  4. Fabrication of a three dimensional particle focusing microfluidic device using a 3D printer, PDMS, and glass

    NASA Astrophysics Data System (ADS)

    Collette, Robyn; Rosen, Daniel; Shirk, Kathryn

    Microfluidic devices have high importance in fields such as bioanalysis because they can manipulate volumes of fluid in the range of microliters to picoliters. Small samples can be quickly and easily tested using complex microfluidic devices. Typically, these devices are created through lithography techniques, which can be costly and time consuming. It has been shown that inexpensive microfluidic devices can be produced quickly using a 3D printer and PDMS. However, a size limitation prohibits the fabrication of precisely controlled microchannels. By using shrinking materials in combination with 3D printing of flow-focusing geometries, this limitation can be overcome. This research seeks to employ these techniques to quickly fabricate an inexpensive, working device with three dimensional particle focusing capabilities. By modifying the channel geometry, colloidal particles in a solution will be focused into a single beam when passed through this device. The ability to focus particles is necessary for a variety of biological applications which requires precise detection and characterization of particles in a sample. We would like to thank the Shippensburg University Undergraduate Research Grant Program for their generous funding.

  5. Characterization of New PEEK/HA Composites with 3D HA Network Fabricated by Extrusion Freeforming.

    PubMed

    Vaezi, Mohammad; Black, Cameron; Gibbs, David M R; Oreffo, Richard O C; Brady, Mark; Moshrefi-Torbati, Mohamed; Yang, Shoufeng

    2016-01-01

    Addition of bioactive materials such as calcium phosphates or Bioglass, and incorporation of porosity into polyetheretherketone (PEEK) has been identified as an effective approach to improve bone-implant interfaces and osseointegration of PEEK-based devices. In this paper, a novel production technique based on the extrusion freeforming method is proposed that yields a bioactive PEEK/hydroxyapatite (PEEK/HA) composite with a unique configuration in which the bioactive phase (i.e., HA) distribution is computer-controlled within a PEEK matrix. The 100% interconnectivity of the HA network in the biocomposite confers an advantage over alternative forms of other microstructural configurations. Moreover, the technique can be employed to produce porous PEEK structures with controlled pore size and distribution, facilitating greater cellular infiltration and biological integration of PEEK composites within patient tissue. The results of unconfined, uniaxial compressive tests on these new PEEK/HA biocomposites with 40% HA under both static and cyclic mode were promising, showing the composites possess yield and compressive strength within the range of human cortical bone suitable for load bearing applications. In addition, preliminary evidence supporting initial biological safety of the new technique developed is demonstrated in this paper. Sufficient cell attachment, sustained viability in contact with the sample over a seven-day period, evidence of cell bridging and matrix deposition all confirmed excellent biocompatibility. PMID:27240326

  6. Contrast Enhancement of MicroCT Scans to Aid 3D Modelling of Carbon Fibre Fabric Composites

    NASA Astrophysics Data System (ADS)

    Djukic, Luke P.; Pearce, Garth M.; Herszberg, Israel; Bannister, Michael K.; Mollenhauer, David H.

    2013-12-01

    This paper presents a methodology for volume capture and rendering of plain weave and multi-layer fabric meso-architectures within a consolidated, cured laminate. Micro X-ray Computed Tomography (MicroCT) is an excellent tool for the non-destructive visualisation of material microstructures however the contrast between tows and resin is poor for carbon fibre composites. Firstly, this paper demonstrates techniques to improve the contrast of the microCT images by introducing higher density materials such as gold, iodine and glass into the fabric. Two approaches were demonstrated to be effective for enhancing the differentiation between the tows in the reconstructed microCT visualisations. Secondly, a method of generating three-dimensional volume models of woven composites using microCT scan data is discussed. The process of generating a model is explained from initial manufacture with the aid of an example plain weave fabric. These methods are to be used in the finite element modelling of three-dimensional fabric preforms in future work.

  7. Fabrication of 3D porous SF/β-TCP hybrid scaffolds for bone tissue reconstruction.

    PubMed

    Park, Hyun Jung; Min, Kyung Dan; Lee, Min Chae; Kim, Soo Hyeon; Lee, Ok Joo; Ju, Hyung Woo; Moon, Bo Mi; Lee, Jung Min; Park, Ye Ri; Kim, Dong Wook; Jeong, Ju Yeon; Park, Chan Hum

    2016-07-01

    Bio-ceramic is a biomaterial actively studied in the field of bone tissue engineering. But, only certain ceramic materials can resolve the corrosion problem and possess the biological affinity of conventional metal biomaterials. Therefore, the recent development of composites of hybrid composites and polymers has been widely studied. In this study, we aimed to select the best scaffold of silk fibroin and β-TCP hybrid for bone tissue engineering. We fabricated three groups of scaffold such as SF (silk fibroin scaffold), GS (silk fibroin/small granule size of β-TCP scaffold) and GM (silk fibroin/medium granule size of β-TCP scaffold), and we compared the characteristics of each group. During characterization of the scaffold, we used scanning electron microscopy (SEM) and a Fourier transform infrared spectroscopy (FTIR) for structural analysis. We compared the physiological properties of the scaffold regarding the swelling ratio, water uptake and porosity. To evaluate the mechanical properties, we examined the compressive strength of the scaffold. During in vitro testing, we evaluated cell attachment and cell proliferation (CCK-8). Finally, we confirmed in vivo new bone regeneration from the implanted scaffolds using histological staining and micro-CT. From these evaluations, the fabricated scaffold demonstrated high porosity with good inter-pore connectivity, showed good biocompatibility and high compressive strength and modulus. In particular, the present study indicates that the GM scaffold using β-TCP accelerates new bone regeneration of implanted scaffolds. Accordingly, our scaffold is expected to act a useful application in the field of bone tissue engineering. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 104A: 1779-1787, 2016. PMID:26999521

  8. Stochastic Multi-Scale Reconstruction of 3D Microstructure Consisting of Polycrystalline Grains and Second-Phase Particles from 2D Micrographs

    NASA Astrophysics Data System (ADS)

    Chen, Shaohua; Kirubanandham, Antony; Chawla, Nikhilesh; Jiao, Yang

    2016-03-01

    An accurate knowledge of the 3D polycrystalline microstructure of a material is crucial to its property prediction, performance optimization, and design. Here, we present a multi-scale computational scheme that allows one to stochastically reconstruct the 3D microstructure of a highly heterogeneous polycrystalline material with large variation in grain size, morphology, and spatial distribution, as well as the distribution of second-phase particles, from single-2D electron back-scattered diffraction (EBSD) micrograph. Specifically, the two-point correlation functions S 2 are employed to statistically characterize grain morphology, orientation, and spatial distribution and are incorporated into the simulated annealing procedure for microstructure reconstruction. During the reconstruction, the original polycrystalline microstructure is coarsened such that the large grains are reconstructed first and the smaller ones are generated later. The second-phase particles are then inserted into the reconstructed polycrystalline material based on the pair-correlation function g 2 sampled from the 2D back-scattered electron micrograph. The utility of our multi-scale scheme is demonstrated by successfully reconstructing a highly heterogeneous polycrystalline Sn-rich solder joint with Cu6Sn5 intermetallic particles. The accuracy of our reconstruction is ascertained by comparing the virtual microstructure with the actual 3D structure of the joint obtained via serial sectioning techniques.

  9. A nano-microstructured artificial-hair-cell-type sensor based on topologically graded 3D carbon nanotube bundles

    NASA Astrophysics Data System (ADS)

    Yilmazoglu, O.; Yadav, S.; Cicek, D.; Schneider, J. J.

    2016-09-01

    A design for a unique artificial-hair-cell-type sensor (AHCTS) based entirely on 3D-structured, vertically aligned carbon nanotube (CNT) bundles is introduced. Standard microfabrication techniques were used for the straightforward micro-nano integration of vertically aligned carbon nanotube arrays composed of low-layer multi-walled CNTs (two to six layers). The mechanical properties of the carbon nanotube bundles were intensively characterized with regard to various substrates and CNT morphology, e.g. bundle height. The CNT bundles display excellent flexibility and mechanical stability for lateral bending, showing high tear resistance. The integrated 3D CNT sensor can detect three-dimensional forces using the deflection or compression of a central CNT bundle which changes the contact resistance to the shorter neighboring bundles. The complete sensor system can be fabricated using a single chemical vapor deposition (CVD) process step. Moreover, sophisticated external contacts to the surroundings are not necessary for signal detection. No additional sensors or external bias for signal detection are required. This simplifies the miniaturization and the integration of these nanostructures for future microsystem set-ups. The new nanostructured sensor system exhibits an average sensitivity of 2100 ppm in the linear regime with the relative resistance change per micron (ppm μm‑1) of the individual CNT bundle tip deflection. Furthermore, experiments have shown highly sensitive piezoresistive behavior with an electrical resistance decrease of up to ∼11% at 50 μm mechanical deflection. The detection sensitivity is as low as 1 μm of deflection, and thus highly comparable with the tactile hair sensors of insects, having typical thresholds on the order of 30–50 μm. The AHCTS can easily be adapted and applied as a flow, tactile or acceleration sensor as well as a vibration sensor. Potential applications of the latter might come up in artificial cochlear systems. In

  10. Improving thermoluminescence response through the fabrication of novel microstructured fibers

    NASA Astrophysics Data System (ADS)

    Dermosesian, E.; Amouzad Mahdiraji, G.; Mahamd Adikan, F. R.; Bradley, D. A.

    2015-11-01

    We present a novel technique aimed at improving upon the thermoluminescence (TL) response of optical fibers. The technique, based on the stack-and-draw method, is more conventionally used for microstructured optical fiber (MOF) fabrication. Utilizing the approach, the TL response of a single microstructured fiber can be shown to substantially improve upon that of a single capillary fiber, approaching a 30 fold increase in sensitivity. Present results provide strong support for the idea that by collapsing and fusing the surface walls of stacked fibers, strain-related defects are created, increasing the TL yield many times over. The substantial increase in sensitivity of these glass-based systems point to more extensive applications, the production of such detectors allowing versatile use, down to much lower doses than currently available using single capillary fibers.

  11. An extremely simple method for fabricating 3D protein microarrays with an anti-fouling background and high protein capacity.

    PubMed

    Lin, Zhifeng; Ma, Yuhong; Zhao, Changwen; Chen, Ruichao; Zhu, Xing; Zhang, Lihua; Yan, Xu; Yang, Wantai

    2014-07-21

    Protein microarrays have become vital tools for various applications in biomedicine and bio-analysis during the past decade. The intense requirements for a lower detection limit and industrialization in this area have resulted in a persistent pursuit to fabricate protein microarrays with a low background and high signal intensity via simple methods. Here, we report on an extremely simple strategy to create three-dimensional (3D) protein microarrays with an anti-fouling background and a high protein capacity by photo-induced surface sequential controlled/living graft polymerization developed in our lab. According to this strategy, "dormant" groups of isopropyl thioxanthone semipinacol (ITXSP) were first introduced to a polymeric substrate through ultraviolet (UV)-induced surface abstraction of hydrogen, followed by a coupling reaction. Under visible light irradiation, the ITXSP groups were photolyzed to initiate surface living graft polymerization of poly(ethylene glycol) methyl methacrylate (PEGMMA), thus introducing PEG brushes to the substrate to generate a full anti-fouling background. Due to the living nature of this graft polymerization, there were still ITXSP groups on the chain ends of the PEG brushes. Therefore, by in situ secondary living graft cross-linking copolymerization of glycidyl methacrylate (GMA) and polyethylene glycol diacrylate (PEGDA), we could finally plant height-controllable cylinder microarrays of a 3D PEG network containing reactive epoxy groups onto the PEG brushes. Through a commonly used reaction of amine and epoxy groups, the proteins could readily be covalently immobilized onto the microarrays. This delicate design aims to overcome two universal limitations in protein microarrays: a full anti-fouling background can effectively eliminate noise caused by non-specific absorption and a 3D reactive network provides a larger protein-loading capacity to improve signal intensity. The results of non-specific protein absorption tests

  12. Photodeposition Method For Fabricating A Three-Dimensional, Patterned Polymer Microstructure

    DOEpatents

    Walt, David R.; Healey, Brian G.

    2001-03-13

    The present invention is a photodeposition methodology for fabricating a three-dimensional patterned polymer microstructure. A variety of polymeric structures can be fabricated on solid substrates using unitary fiber optic arrays for light delivery. The methodology allows micrometer-scale photopatterning for the fabricated structures using masks substantially larger than the desired dimensions of the microstructure.

  13. Fabrication of corner cube array retro-reflective structure with DLP-based 3D printing technology

    NASA Astrophysics Data System (ADS)

    Riahi, Mohammadreza

    2016-06-01

    In this article, the fabrication of a corner cube array retro-reflective structure is presented by using DLP-based 3D printing technology. In this additive manufacturing technology a pattern of a cube corner array is designed in a computer and sliced with specific software. The image of each slice is then projected from the bottom side of a reservoir, containing UV cure resin, utilizing a DLP video projector. The projected area is cured and attached to a base plate. This process is repeated until the entire part is made. The best orientation of the printing process and the effect of layer thicknesses on the surface finish of the cube has been investigated. The thermal reflow surface finishing and replication with soft molding has also been presented in this article.

  14. 3D microfluidic chips with integrated functional microelements fabricated by a femtosecond laser for studying the gliding mechanism of cyanobacteria.

    PubMed

    Hanada, Yasutaka; Sugioka, Koji; Shihira-Ishikawa, Ikuko; Kawano, Hiroyuki; Miyawaki, Atsushi; Midorikawa, Katsumi

    2011-06-21

    Phormidium, a genus of filamentous cyanobacteria, forms endosymbiotic associations with seedling roots that accelerate the growth of the vegetable seedlings. Understanding the gliding mechanism of Phormidium will facilitate improved formation of this association and increased vegetable production. To observe the gliding movements, we fabricated various microfluidic chips termed nanoaquariums using a femtosecond (fs) laser. Direct fs laser writing, followed by annealing and successive wet etching in dilute hydrofluoric acid solution, can easily produce three-dimensional (3D) microfluidics with different structures embedded in a photostructurable glass. Using the fs laser, optical waveguides and filters were integrated with the microfluidic structures in the microchips, allowing the gliding mechanism to be more easily clarified. Using this apparatus, we found that CO(2) secreted from the seedling root attracts Phormidium in the presence of light, and determined the light intensity and specific wavelength necessary for gliding. PMID:21562650

  15. Fabrication of corner cube array retro-reflective structure with DLP-based 3D printing technology

    NASA Astrophysics Data System (ADS)

    Riahi, Mohammadreza

    2016-04-01

    In this article, the fabrication of a corner cube array retro-reflective structure is presented by using DLP-based 3D printing technology. In this additive manufacturing technology a pattern of a cube corner array is designed in a computer and sliced with specific software. The image of each slice is then projected from the bottom side of a reservoir, containing UV cure resin, utilizing a DLP video projector. The projected area is cured and attached to a base plate. This process is repeated until the entire part is made. The best orientation of the printing process and the effect of layer thicknesses on the surface finish of the cube has been investigated. The thermal reflow surface finishing and replication with soft molding has also been presented in this article.

  16. Fabrication and characterization of a chalcogenide-tellurite composite microstructure fiber with high nonlinearity.

    PubMed

    Liao, Meisong; Chaudhari, Chitrarekha; Qin, Guanshi; Yan, Xin; Kito, Chihiro; Suzuki, Takenobu; Ohishi, Yasutake; Matsumoto, Morio; Misumi, Takashi

    2009-11-23

    A highly nonlinear composite fiber, which has a 1.5 microm chalcogenide glass core surrounded by a tellurite glass microstructure cladding, has been fabricated by the method of stack and draw. A tellurite glass capillary containing a As(2)S(3) rod was sealed with negative pressure inside. Then this capillary and other empty capillaries were stacked into a tellurite glass tube, and elongated into a cane. This cane was then inserted into another tellurite glass jacket tube and drawn into the composite microstructure fiber. The fiber has a flattened chromatic dispersion together with a zero dispersion wavelength located in the near infrared range. The propagation losses at 1.55 microm were 18.3 dB/m. The nonlinear coefficient at 1.55 microm was 9.3 m(-1)W(-1). Such a high nonlinear coefficient counteracts the high propagation losses to a large extent. A supercontinuum spectrum of 20-dB bandwidth covering 800-2400 nm was generated by this composite microstructure fiber. PMID:19997402

  17. A nano-microstructured artificial-hair-cell-type sensor based on topologically graded 3D carbon nanotube bundles.

    PubMed

    Yilmazoglu, O; Yadav, S; Cicek, D; Schneider, J J

    2016-09-01

    A design for a unique artificial-hair-cell-type sensor (AHCTS) based entirely on 3D-structured, vertically aligned carbon nanotube (CNT) bundles is introduced. Standard microfabrication techniques were used for the straightforward micro-nano integration of vertically aligned carbon nanotube arrays composed of low-layer multi-walled CNTs (two to six layers). The mechanical properties of the carbon nanotube bundles were intensively characterized with regard to various substrates and CNT morphology, e.g. bundle height. The CNT bundles display excellent flexibility and mechanical stability for lateral bending, showing high tear resistance. The integrated 3D CNT sensor can detect three-dimensional forces using the deflection or compression of a central CNT bundle which changes the contact resistance to the shorter neighboring bundles. The complete sensor system can be fabricated using a single chemical vapor deposition (CVD) process step. Moreover, sophisticated external contacts to the surroundings are not necessary for signal detection. No additional sensors or external bias for signal detection are required. This simplifies the miniaturization and the integration of these nanostructures for future microsystem set-ups. The new nanostructured sensor system exhibits an average sensitivity of 2100 ppm in the linear regime with the relative resistance change per micron (ppm μm(-1)) of the individual CNT bundle tip deflection. Furthermore, experiments have shown highly sensitive piezoresistive behavior with an electrical resistance decrease of up to ∼11% at 50 μm mechanical deflection. The detection sensitivity is as low as 1 μm of deflection, and thus highly comparable with the tactile hair sensors of insects, having typical thresholds on the order of 30-50 μm. The AHCTS can easily be adapted and applied as a flow, tactile or acceleration sensor as well as a vibration sensor. Potential applications of the latter might come up in artificial cochlear systems. In

  18. SU-C-213-02: Characterizing 3D Printing in the Fabrication of Variable Density Phantoms

    SciTech Connect

    Madamesila, J; McGeachy, P; Villarreal-Barajas, J; Khan, R

    2015-06-15

    Purpose: In this work, we present characterization, process flow, quality control and application of 3D fabricated low density phantoms for radiotherapy quality assurance. Methods: A Rostock delta 3D printer using polystyrene filament of diameter 1.75 mm was used to print geometric volumes of 2×2×1 cm{sup 3} of varying densities. The variable densities of 0.1 to 0.75 g/cm {sup 3} were created by modulating the infill. A computed tomography (CT) scan was performed to establish an infill-density calibration curve as well as characterize the quality of the print such as uniformity and the infill pattern. The time required to print these volumes was also recorded. Using the calibration, two low density cones (0.19, 0.52 g/cm{sup 3}) were printed and benchmarked against commercially available phantoms. The dosimetric validation of the low density scaling of Anisotropic Analytical Algorithm (AAA) was performed by using a 0.5 g/cm{sup 3} slab of 10×10×2.4 cm{sup 3} with EBT3 GafChromic film. The gamma analysis at 3%/3mm criteria were compared for the measured and computed dose planes. Results: Analysis of the volume of air pockets in the infill resulted in a reasonable uniformity for densities 0.4 to 0.75 g/cm{sup 3}. Printed phantoms with densities below 0.4 g/cm{sup 3} exhibited a higher ratio of air to polystyrene resulting in large non-uniformity. Compared to the commercial inserts, good agreement was observed only for the printed 0.52 g/cm{sup 3} cone. Dosimetric comparison for a printed low density volume placed in-between layers of solid water resulted in >95% gamma agreement between AAA calculated dose planes and measured EBT3 films for a 6MV 5×5 cm{sup 2} clinical beam. The comparison showed disagreement in the penumbra region. Conclusion: In conclusion, 3D printing technology opens the door to desktop fabrication of variable density phantoms at economical prices in an efficient manner for the quality assurance needs of a small clinic.

  19. Evolution of Mineral Fabrics and Microstructures in Kimmeridge Shale upon Kerogen Maturation

    NASA Astrophysics Data System (ADS)

    Kanitpanyacharoen, J.; Vanorio, T.; Liu, Y.; Xiao, X.; Benmore, C.

    2013-12-01

    Shale has increasingly received attention due to its recent recognition as a potential game changer of US energy outlook. However a fundamental relationship between mineral lattice preferred orientation (LPO or fabrics), kerogen, and elastic properties of shale remains questionable. Here we present different synchrotron X-ray techniques to capture microstructural transformations in Kimmeridge Shale upon temperature-induced anhydrous maturation. At room condition, the sample is mainly composed of clays 72 vol.%, quartz (15 vol.%), pyrite (11 vol.%), and a small amount of pyrite (2 vol.%). Illite-group is the dominating clay with 50 vol.% present. Illite-mica (30 vol.%) shows the highest degree of LPO (3.33 m.r.d.), which is consistent with previous studies (Wenk et al 2008, Voltolini et al. 2009, Kanitpanyacharoen et al. 2011). However the illite-smectite group exhibits relatively weaker degree of LPO due to the disordered nature of the structure. Chlorite shows the least degree of LPO due to its total clay content, which is only 2 vol.%. Upon heating to 300 °C, the phase proportions did not change much and the degrees of all clay minerals fabrics remain fairly consistent. The high-resolution 3D imaging technique allows us to record different stages of kerogen transformation, particularly a significant gas bubble formation at 400 °C. Upon heating up to 500 °C, kerogen shrinkage (17 vol.%) and clay matrix expansion continued and appeared more pronounced after 10 hours of heating. The consistent results from both experiments confirm that no significant change of mineral fabrics and microstructural features below 300 °C observed. These findings further infer that the evolution of clay fabrics and kerogen maturation may affect elastic anisotropy consistently at the temperature below 300 °C. The reduction of kerogen greatly influences elastic anisotropy properties and the identification of the promising source in the hydrocarbon reservoir.

  20. Fabrication of a novel dual mode cholesterol biosensor using titanium dioxide nanowire bridged 3D graphene nanostacks.

    PubMed

    Komathi, S; Muthuchamy, N; Lee, K-P; Gopalan, A-I

    2016-10-15

    Herein, we fabricated a novel electrochemical-photoelectrochemical (PEC) dual-mode cholesterol biosensor based on graphene (G) sheets interconnected-graphene embedded titanium nanowires (TiO2(G)-NWs) 3D nanostacks (designated as G/Ti(G) 3DNS) by exploiting the beneficial characteristics of G and TiO2-NWs to achieve good selectivity and high sensitivity for cholesterol detection. The G/Ti(G) 3DNS was fabricated by the reaction between functionalized G and TiO2(G)-NWs. Cholesterol oxidase (ChOx) was subsequently immobilized in to G/Ti(G) 3DNS using chitosan (CS) as the binder and the dual mode G/Ti(G) 3DNS/CS/ChOx biosensor was fabricated. The electro-optical properties of the G/Ti(G) 3DNS/CS/ChOx bioelectrode were characterized by cyclic voltammetry and UV-vis diffuse reflection spectroscopy. The cyclic voltammetry of immobilized ChOx showed a pair of well-defined redox peaks indicating direct electron transfer (DET) of ChOx. The amperometric reduction peak current (at -0.05V) linearly increased with increase in cholesterol concentration. The G/Ti(G) 3DNS/CS/ChOx bioelectrode was selective to cholesterol with a remarkable sensitivity (3.82μA/cm(2)mM) and a lower detection limit (6μM). Also, G/Ti(G) 3DNS/CS/ChOx functioned as photoelectrode and exhibited selective detection of cholesterol under a low bias voltage and light irradiation. Kinetic parameters, reproducibility, repeatability, storage stability and effect of temperature and pH were evaluated. We envisage that G/Ti(G) 3DNS with its prospective characteristics, would be a promising material for wide range of biosensing applications. PMID:26611566

  1. Facile Bench-Top Fabrication of Enclosed Circular Microchannels Provides 3D Confined Structure for Growth of Prostate Epithelial Cells

    PubMed Central

    Dolega, Monika E.; Wagh, Jayesh; Gerbaud, Sophie; Kermarrec, Frederique; Alcaraz, Jean-Pierre; Martin, Donald K.; Gidrol, Xavier; Picollet-D’hahan, Nathalie

    2014-01-01

    We present a simple bench-top method to fabricate enclosed circular channels for biological experiments. Fabricating the channels takes less than 2 hours by using glass capillaries of various diameters (from 100 µm up to 400 µm) as a mould in PDMS. The inner surface of microchannels prepared in this way was coated with a thin membrane of either Matrigel or a layer-by-layer polyelectrolyte to control cellular adhesion. The microchannels were then used as scaffolds for 3D-confined epithelial cell culture. To show that our device can be used with several epithelial cell types from exocrine glandular tissues, we performed our biological studies on adherent epithelial prostate cells (non-malignant RWPE-1 and invasive PC3) and also on breast (non-malignant MCF10A) cells We observed that in static conditions cells adhere and proliferate to form a confluent layer in channels of 150 µm in diameter and larger, whereas cellular viability decreases with decreasing diameter of the channel. Matrigel and PSS (poly (sodium 4-styrenesulphonate)) promote cell adhesion, whereas the cell proliferation rate was reduced on the PAH (poly (allylamine hydrochloride))-terminated surface. Moreover infusing channels with a continuous flow did not induce any cellular detachment. Our system is designed to simply grow cells in a microchannel structure and could be easily fabricated in any biological laboratory. It offers opportunities to grow epithelial cells that support the formation of a light. This system could be eventually used, for example, to collect cellular secretions, or study cell responses to graduated hypoxia conditions, to chemicals (drugs, siRNA, …) and/or physiological shear stress. PMID:24945245

  2. Comparison of focused ion beam versus nano-scale X-ray computed tomography for resolving 3-D microstructures of porous fuel cell materials

    NASA Astrophysics Data System (ADS)

    Wargo, E. A.; Kotaka, T.; Tabuchi, Y.; Kumbur, E. C.

    2013-11-01

    Focused ion beam-scanning electron microscopy (FIB-SEM) and nano-scale X-ray computed tomography (nano-CT) have emerged as two popular nanotomography techniques for quantifying the 3-D microstructure of porous materials. The objective of this study is to assess the unique features and limitations of FIB-SEM and nano-CT in capturing the 3-D microstructure and structure-related transport properties of porous fuel cell materials. As a test case, a sample of a micro-porous layer used in polymer electrolyte fuel cells is analyzed to obtain 3-D microstructure datasets using these two nanotomography techniques. For quantitative comparison purposes, several key transport properties are determined for these two datasets, including the porosity, pore connectivity, tortuosity, structural diffusivity coefficient, and chord length (i.e., void size) distributions. The results obtained for both datasets are evaluated against each other and experimental data when available. Additionally, these two techniques are compared qualitatively in terms of the acquired images, image segmentation, and general systems operation. The particular advantages and disadvantages of both techniques are highlighted, along with suggestions for best practice.

  3. Multiscale microstructural characterization of Sn-rich alloys by three dimensional (3D) X-ray synchrotron tomography and focused ion beam (FIB) tomography

    SciTech Connect

    Yazzie, K.E.; Williams, J.J.; Phillips, N.C.; De Carlo, F.; Chawla, N.

    2012-08-15

    Sn-rich (Pb-free) alloys serve as electrical and mechanical interconnects in electronic packaging. It is critical to quantify the microstructures of Sn-rich alloys to obtain a fundamental understanding of their properties. In this work, the intermetallic precipitates in Sn-3.5Ag and Sn-0.7Cu, and globular lamellae in Sn-37Pb solder joints were visualized and quantified using 3D X-ray synchrotron tomography and focused ion beam (FIB) tomography. 3D reconstructions were analyzed to extract statistics on particle size and spatial distribution. In the Sn-Pb alloy the interconnectivity of Sn-rich and Pb-rich constituents was quantified. It will be shown that multiscale characterization using 3D X-ray and FIB tomography enabled the characterization of the complex morphology, distribution, and statistics of precipitates and contiguous phases over a range of length scales. - Highlights: Black-Right-Pointing-Pointer Multiscale characterization by X-ray synchrotron and focused ion beam tomography. Black-Right-Pointing-Pointer Characterized microstructural features in several Sn-based alloys. Black-Right-Pointing-Pointer Quantified size, fraction, and clustering of microstructural features.

  4. Combination therapy with BMP-2 and BMSCs enhances bone healing efficacy of PCL scaffold fabricated using the 3D plotting system in a large segmental defect model.

    PubMed

    Kang, Sun-Woong; Bae, Ji-Hoon; Park, Su-A; Kim, Wan-Doo; Park, Mi-Su; Ko, You-Jin; Jang, Hyon-Seok; Park, Jung-Ho

    2012-07-01

    The three-dimensional (3D) plotting system is a rapidly-developing scaffold fabrication method for bone tissue engineering. It yields a highly porous and inter-connective structure without the use of cytotoxic solvents. However, the therapeutic effects of a scaffold fabricated using the 3D plotting system in a large segmental defect model have not yet been demonstrated. We have tested two hypotheses: whether the bone healing efficacy of scaffold fabricated using the 3D plotting system would be enhanced by bone marrow-derived mesenchymal stem cell (BMSC) transplantation; and whether the combination of bone morphogenetic protein-2 (BMP-2) administration and BMSC transplantation onto the scaffold would act synergistically to enhance bone regeneration in a large segmental defect model. The use of the combined therapy did increase bone regeneration further as compared to that with monotherapy in large segmental bone defects. PMID:22447098

  5. Fabrication and characterization of a 3-D non-homogeneous tissue-like mouse phantom for optical imaging

    NASA Astrophysics Data System (ADS)

    Avtzi, Stella; Zacharopoulos, Athanasios; Psycharakis, Stylianos; Zacharakis, Giannis

    2013-11-01

    In vivo optical imaging of biological tissue not only requires the development of new theoretical models and experimental procedures, but also the design and construction of realistic tissue-mimicking phantoms. However, most of the phantoms available currently in literature or the market, have either simple geometrical shapes (cubes, slabs, cylinders) or when realistic in shape they use homogeneous approximations of the tissue or animal under investigation. The goal of this study is to develop a non-homogeneous realistic phantom that matches the anatomical geometry and optical characteristics of the mouse head in the visible and near-infrared spectral range. The fabrication of the phantom consisted of three stages. Initially, anatomical information extracted from either mouse head atlases or structural imaging modalities (MRI, XCT) was used to design a digital phantom comprising of the three main layers of the mouse head; the brain, skull and skin. Based on that, initial prototypes were manufactured by using accurate 3D printing, allowing complex objects to be built layer by layer with sub-millimeter resolution. During the second stage the fabrication of individual molds was performed by embedding the prototypes into a rubber-like silicone mixture. In the final stage the detailed phantom was constructed by loading the molds with epoxy resin of controlled optical properties. The optical properties of the resin were regulated by using appropriate quantities of India ink and intralipid. The final phantom consisted of 3 layers, each one with different absorption and scattering coefficient (μa,μs) to simulate the region of the mouse brain, skull and skin.

  6. A four level silicon microstructure fabrication by DRIE

    NASA Astrophysics Data System (ADS)

    Rahiminejad, S.; Cegielski, P.; Abassi, M.; Enoksson, P.

    2016-08-01

    We present a four level Si microstructure fabrication process with depths ranging from 70–400 μm. All four levels are etched from the same side, by using four hard masks (\\text{Si}{{\\text{O}}2} , Al, AZ4562 photo resist, and Al). The choice of the hard masks and their relative selectivity will be discussed. Also two different deep reactive ion etching (DRIE) processes, performed in two different machines, are compared and evaluated. The process evaluation and discussions are based on the vertical walls deviation from a right angle, the surface roughness and the resolution. In the end, a solution is proposed to remove spikes and grassing which appeared during both DRIE processes, and the impact of removing them from the surfaces is discussed.

  7. Fabrication of poly(ethylene glycol) hydrogel microstructures using photolithography.

    PubMed

    Revzin, A; Russell, R J; Yadavalli, V K; Koh, W G; Deister, C; Hile, D D; Mellott, M B; Pishko, M V

    2001-09-01

    The fabrication of hydrogel microstructures based upon poly(ethylene glycol) diacrylates, dimethacrylates, and tetraacrylates patterned photolithographically on silicon or glass substrates is described. A silicon/silicon dioxide surface was treated with 3-(trichlorosilyl)propyl methacrylate to form a self-assembled monolayer (SAM) with pendant acrylate groups. The SAM presence on the surface was verified using ellipsometry and time-of-flight secondary ion mass spectrometry. A solution containing an acrylated or methacrylated poly(ethylene glycol) derivative and a photoinitiator (2,2-dimethoxy-2-phenylacetophenone) was spin-coated onto the treated substrate, exposed to 365 nm ultraviolet light through a photomask, and developed with either toluene, water, or supercritical CO2. As a result of this process, three-dimensional, cross-linked PEG hydrogel microstructures were immobilized on the surface. Diameters of cylindrical array members were varied from 600 to 7 micrometers by the use of different photomasks, while height varied from 3 to 12 micrometers, depending on the molecular weight of the PEG macromer. In the case of 7 micrometers diameter elements, as many as 400 elements were reproducibly generated in a 1 mm2 square pattern. The resultant hydrogel patterns were hydrated for as long as 3 weeks without delamination from the substrate. In addition, micropatterning of different molecular weights of PEG was demonstrated. Arrays of hydrogel disks containing an immobilized protein conjugated to a pH sensitive fluorophore were also prepared. The pH sensitivity of the gel-immobilized dye was similar to that in an aqueous buffer, and no leaching of the dye-labeled protein from the hydrogel microstructure was observed over a 1 week period. Changes in fluorescence were also observed for immobilized fluorophore labeled acetylcholine esterase upon the addition of acetyl acholine. PMID:12448421

  8. Fabrication of poly(ethylene glycol) hydrogel microstructures using photolithography

    NASA Technical Reports Server (NTRS)

    Revzin, A.; Russell, R. J.; Yadavalli, V. K.; Koh, W. G.; Deister, C.; Hile, D. D.; Mellott, M. B.; Pishko, M. V.

    2001-01-01

    The fabrication of hydrogel microstructures based upon poly(ethylene glycol) diacrylates, dimethacrylates, and tetraacrylates patterned photolithographically on silicon or glass substrates is described. A silicon/silicon dioxide surface was treated with 3-(trichlorosilyl)propyl methacrylate to form a self-assembled monolayer (SAM) with pendant acrylate groups. The SAM presence on the surface was verified using ellipsometry and time-of-flight secondary ion mass spectrometry. A solution containing an acrylated or methacrylated poly(ethylene glycol) derivative and a photoinitiator (2,2-dimethoxy-2-phenylacetophenone) was spin-coated onto the treated substrate, exposed to 365 nm ultraviolet light through a photomask, and developed with either toluene, water, or supercritical CO2. As a result of this process, three-dimensional, cross-linked PEG hydrogel microstructures were immobilized on the surface. Diameters of cylindrical array members were varied from 600 to 7 micrometers by the use of different photomasks, while height varied from 3 to 12 micrometers, depending on the molecular weight of the PEG macromer. In the case of 7 micrometers diameter elements, as many as 400 elements were reproducibly generated in a 1 mm2 square pattern. The resultant hydrogel patterns were hydrated for as long as 3 weeks without delamination from the substrate. In addition, micropatterning of different molecular weights of PEG was demonstrated. Arrays of hydrogel disks containing an immobilized protein conjugated to a pH sensitive fluorophore were also prepared. The pH sensitivity of the gel-immobilized dye was similar to that in an aqueous buffer, and no leaching of the dye-labeled protein from the hydrogel microstructure was observed over a 1 week period. Changes in fluorescence were also observed for immobilized fluorophore labeled acetylcholine esterase upon the addition of acetyl acholine.

  9. Portable, Easy-to-Operate, and Antifouling Microcapsule Array Chips Fabricated by 3D Ice Printing for Visual Target Detection.

    PubMed

    Zhang, Hong-Ze; Zhang, Fang-Ting; Zhang, Xiao-Hui; Huang, Dong; Zhou, Ying-Lin; Li, Zhi-Hong; Zhang, Xin-Xiang

    2015-06-16

    Herein, we proposed a portable, easy-to-operate, and antifouling microcapsule array chip for target detection. This prepackaged chip was fabricated by innovative and cost-effective 3D ice printing integrating with photopolymerization sealing which could eliminate complicated preparation of wet chemistry and effectively resist outside contaminants. Only a small volume of sample (2 μL for each microcapsule) was consumed to fulfill the assay. All the reagents required for the analysis were stored in ice form within the microcapsule before use, which guaranteed the long-term stability of microcapsule array chips. Nitrite and glucose were chosen as models for proof of concept to achieve an instant quantitative detection by naked eyes without the need of external sophisticated instruments. The simplicity, low cost, and small sample consumption endowed ice-printing microcapsule array chips with potential commercial value in the fields of on-site environmental monitoring, medical diagnostics, and rapid high-throughput point-of-care quantitative assay. PMID:25970032

  10. Design, Fabrication and Characterization of a Low-Impedance 3D Electrode Array System for Neuro-Electrophysiology

    PubMed Central

    Kusko, Mihaela; Craciunoiu, Florea; Amuzescu, Bogdan; Halitzchi, Ferdinand; Selescu, Tudor; Radoi, Antonio; Popescu, Marian; Simion, Monica; Bragaru, Adina; Ignat, Teodora

    2012-01-01

    Recent progress in patterned microelectrode manufacturing technology and microfluidics has opened the way to a large variety of cellular and molecular biosensor-based applications. In this extremely diverse and rapidly expanding landscape, silicon-based technologies occupy a special position, given their statute of mature, consolidated, and highly accessible areas of development. Within the present work we report microfabrication procedures and workflows for 3D patterned gold-plated microelectrode arrays (MEA) of different shapes (pyramidal, conical and high aspect ratio), and we provide a detailed characterization of their physical features during all the fabrication steps to have in the end a reliable technology. Moreover, the electrical performances of MEA silicon chips mounted on standardized connector boards via ultrasound wire-bonding have been tested using non-destructive electrochemical methods: linear sweep and cyclic voltammetry, impedance spectroscopy. Further, an experimental recording chamber package suitable for in vitro electrophysiology experiments has been realized using custom-design electronics for electrical stimulus delivery and local field potential recording, included in a complete electrophysiology setup, and the experimental structures have been tested on newborn rat hippocampal slices, yielding similar performance compared to commercially available MEA equipments. PMID:23208555

  11. Structure, Properties, and In Vitro Behavior of Heat-Treated Calcium Sulfate Scaffolds Fabricated by 3D Printing.

    PubMed

    Asadi-Eydivand, Mitra; Solati-Hashjin, Mehran; Shafiei, Seyedeh Sara; Mohammadi, Sepideh; Hafezi, Masoud; Abu Osman, Noor Azuan

    2016-01-01

    The ability of inkjet-based 3D printing (3DP) to fabricate biocompatible ceramics has made it one of the most favorable techniques to generate bone tissue engineering (BTE) scaffolds. Calcium sulfates exhibit various beneficial characteristics, and they can be used as a promising biomaterial in BTE. However, low mechanical performance caused by the brittle character of ceramic materials is the main weakness of 3DP calcium sulfate scaffolds. Moreover, the presence of certain organic matters in the starting powder and binder solution causes products to have high toxicity levels. A post-processing treatment is usually employed to improve the physical, chemical, and biological behaviors of the printed scaffolds. In this study, the effects of heat treatment on the structural, mechanical, and physical characteristics of 3DP calcium sulfate prototypes were investigated. Different microscopy and spectroscopy methods were employed to characterize the printed prototypes. The in vitro cytotoxicity of the specimens was also evaluated before and after heat treatment. Results showed that the as-printed scaffolds and specimens heat treated at 300°C exhibited severe toxicity in vitro but had almost adequate strength. By contrast, the specimens heat treated in the 500°C-1000°C temperature range, although non-toxic, had insufficient mechanical strength, which was mainly attributed to the exit of the organic binder before 500°C and the absence of sufficient densification below 1000°C. The sintering process was accelerated at temperatures higher than 1000°C, resulting in higher compressive strength and less cytotoxicity. An anhydrous form of calcium sulfate was the only crystalline phase existing in the samples heated at 500°C-1150°C. The formation of calcium oxide caused by partial decomposition of calcium sulfate was observed in the specimens heat treated at temperatures higher than 1200°C. Although considerable improvements in cell viability of heat-treated scaffolds were

  12. Structure, Properties, and In Vitro Behavior of Heat-Treated Calcium Sulfate Scaffolds Fabricated by 3D Printing

    PubMed Central

    Asadi-Eydivand, Mitra; Solati-Hashjin, Mehran; Shafiei, Seyedeh Sara; Mohammadi, Sepideh; Hafezi, Masoud; Abu Osman, Noor Azuan

    2016-01-01

    The ability of inkjet-based 3D printing (3DP) to fabricate biocompatible ceramics has made it one of the most favorable techniques to generate bone tissue engineering (BTE) scaffolds. Calcium sulfates exhibit various beneficial characteristics, and they can be used as a promising biomaterial in BTE. However, low mechanical performance caused by the brittle character of ceramic materials is the main weakness of 3DP calcium sulfate scaffolds. Moreover, the presence of certain organic matters in the starting powder and binder solution causes products to have high toxicity levels. A post-processing treatment is usually employed to improve the physical, chemical, and biological behaviors of the printed scaffolds. In this study, the effects of heat treatment on the structural, mechanical, and physical characteristics of 3DP calcium sulfate prototypes were investigated. Different microscopy and spectroscopy methods were employed to characterize the printed prototypes. The in vitro cytotoxicity of the specimens was also evaluated before and after heat treatment. Results showed that the as-printed scaffolds and specimens heat treated at 300°C exhibited severe toxicity in vitro but had almost adequate strength. By contrast, the specimens heat treated in the 500°C–1000°C temperature range, although non-toxic, had insufficient mechanical strength, which was mainly attributed to the exit of the organic binder before 500°C and the absence of sufficient densification below 1000°C. The sintering process was accelerated at temperatures higher than 1000°C, resulting in higher compressive strength and less cytotoxicity. An anhydrous form of calcium sulfate was the only crystalline phase existing in the samples heated at 500°C–1150°C. The formation of calcium oxide caused by partial decomposition of calcium sulfate was observed in the specimens heat treated at temperatures higher than 1200°C. Although considerable improvements in cell viability of heat-treated scaffolds

  13. Real-time in situ characterization of interface dynamics in microstructure formation during 3D-directional solidification of transparent alloys

    NASA Astrophysics Data System (ADS)

    Bergeon, N.; Trivedi, R.; Billia, B.; Echebarria, B.; Karma, A.; Liu, S.; Weiss, C.

    The properties of structural materials are to a large extent determined by the solid microstructure so that the understanding of the fundamental physics of microstructure formation is critical in the engineering of materials. Also, microstructure selection occurs during the dynamical growth process so that in situ observation of spatio-temporal evolution of the solid-liquid interface shape is necessary. Under terrestrial conditions, convection effects dominates in bulk samples which prevent precise characterization of microstructure selection. As the glass ampoule conducts heat better than transparent materials, e.g. succinonitrile, the sample near the wall is cooler and convection arises. This leads to concave interface and non-uniform morphological instability starting at the center, while the region near the wall remains smooth. Diffusion-controlled experiments in thin samples give microstructures that are neither 2D nor 3D. When the spacing between glass plates is smaller than the spacing, the cell shape near the tip is 3D, and becomes 2D away from the tip. Preliminary rigorous phase-field results show that in 3D tube geometry (reasonable approximation for a hexagonal array), axisymmetric cells only exist over a narrow range of spacing whereas in 2D steady-state shapes span a wide range of spacing. A benchmark experimental study in bulk samples is thus required under low gravity conditions. In the frame of the joint work of DSIP and MISOL3D projects, respectively selected by NASA and CNES, microgravity experiments in a model transparent system are planned on ISS using the Directional Solidification Insert in the DECLIC facility. The critical aspects of hardware design, the key fundamental issues identified through 1g-experiments, the proposed study on ISS, and the results of rigorous theoretical modeling will be presented. The cellular/dendritic interface morphologies will be examined by systematically varying the process parameters, yielding insight into the

  14. Depiction of Achilles Tendon Microstructure In-Vivo Using High-Resolution 3D Ultrashort Echo-Time MRI at 7T

    PubMed Central

    Han, Misung; Larson, Peder E. Z.; Liu, Jing; Krug, Roland

    2014-01-01

    Objectives To demonstrate the feasibility of depicting the internal structure of the Achilles tendon in vivo using high-resolution 3D ultrashort echo-time (UTE) magnetic resonance imaging (MRI) at 7T. Materials and Methods For our UTE imaging, a minimum-phase radiofrequency pulse and an anisotropic field-of-view 3D radial acquisition were used to minimize the echo time and scan time. A fat saturation pulse was applied every eight spoke acquisitions to reduce blurring and chemical shift artifacts from fat and to improve dynamic range of the tendon signal. Five healthy volunteers and one patient were scanned with an isotropic spatial resolution of up to 0.6 mm. Fat-suppressed UTE images were qualitatively evaluated and compared to non-fat-suppressed UTE images and longer echo-time images. Results High-resolution UTE imaging was able to visualize the microstructure of the Achilles tendon. Fat suppression substantially improved the depiction of the internal structure. The UTE images revealed a fascicular pattern in the Achilles tendon and fibrocartilage at the tendon insertion. In a patient who had tendon elongation surgery after birth there was clear depiction of disrupted tendon structure. Conclusions High-resolution fat-suppressed 3D UTE imaging at 7T allows for evaluation of the Achilles tendon microstructure in vivo. PMID:24500089

  15. Dynamical microstructure formation in 3D directional solidification of transparent model alloys: in situ characterization in DECLIC Directional Solidification Insert under diffusion transport in microgravity

    NASA Astrophysics Data System (ADS)

    Bergeon, N.; Mota, F. L.; Chen, L.; Tourret, D.; Debierre, J. M.; Guérin, R.; Karma, A.; Billia, B.; Trivedi, R.

    2015-06-01

    To clarify and characterize the fundamental physical mechanisms active in the dynamical formation of three-dimensional (3D) arrays of cells and dendrites under diffusive growth conditions, in situ monitoring of series of experiments on transparent model alloy succinonitrile - 0.24 wt% camphor was carried out under low gravity in the DECLIC Directional Solidification Insert on-board the International Space Station. These experiments offered the very unique opportunity to in situ observe and characterize the whole development of the microstructure in extended 3D patterns. The experimental methods will be first briefly described, including in particular the observation modes and the image analysis procedures developed to quantitatively characterize the patterns. Microgravity environment provided the conditions to get quantitative benchmark data: homogeneous patterns corresponding to homogeneous values of control parameters along the whole interface were obtained. The sequence of microstructure formation will be presented as well as the evolution of the primary spacing which is one of the most important pattern characteristic. Time evolution of this primary spacing during the microstructure development will be analysed to identify the mechanisms of spacing selection and adjustment; the importance of the macroscopic interfacial curvature will be pointed out.

  16. Novel 3D scaffold with enhanced physical and cell response properties for bone tissue regeneration, fabricated by patterned electrospinning/electrospraying.

    PubMed

    Hejazi, Fatemeh; Mirzadeh, Hamid

    2016-09-01

    Developing three dimensional scaffolds mimicking the nanoscale structure of native extracellular matrix is a key parameter in tissue regeneration. In this study, we aimed to introduce a novel 3D structures composed of nanofibers (NF) and micro particles (MP) and compare their efficiency with 2D nanofibrous scaffold. The conventional nanofibrous PCL scaffolds are 2D mats fabricated by the electrospinning technique, whereas the NF/MP and patterned NF/MP PCL scaffolds are three dimensional structures fabricated by a modified electrospinning/electrospraying technique. The mentioned method was carried out by varying the electrospinning solution parameters and use of a metal mesh as the collector. Detailed fabrication process and morphological properties of the fabricated structures is discussed and porosity, pore size and PBS solution absorption value of the prepared structures are reported. Compared with the 2D structure, 3D scaffolds possessed enhanced porosity and pore size which led to the significant increase in their water uptake capacity. In vitro cell experiments were carried out on the prepared structures by the use of MG-63 osteosarcoma cell line. The fabricated 3D structures offered significantly increased cell attachment, spread and diffusion which were confirmed by SEM analysis. In vitro cytocompatibility assessed by MTT colorimetric assay indicated a continuous cell proliferation over 21 days on the innovative 3D structure, while on 2D mat cell proliferation stopped at early time points. Enhanced osteogenic differentiation of the seeded MG-63 cells on 3D scaffold was confirmed by the remarkable ALP activity together with increased and accelerated calcium deposition on this structure compared to 2D mat. Massive and well distributed bone minerals formed on patterned 3D structure were shown by EDX analysis. In comparison between NF/MP quasi-3D and Patterned NF/MP 3D scaffolds, patterned structures proceeded in all of the above properties. As such, the

  17. Fabrication of 4, 5, or 6-fold symmetric 3D photonic structures using single beam and single reflective optical element based holographic lithography

    NASA Astrophysics Data System (ADS)

    George, D.; Lutkenhaus, J.; Lowell, D.; Philipose, U.; Zhang, H.; Poole, Z.; Chen, K.; Lin, Y.

    2015-03-01

    Here we present the holographic fabrication of large area 3D photonic structures using a single reflective optical element (ROE) with a single beam, single exposure process. The ROE consists of a 3D printed plastic support that houses 4, 5, or 6-fold symmetrically arranged reflecting surfaces which redirect a central beam into multiple side beams in an umbrella configuration to be used in multi-beam holography. With a circular polarized beam incident to silicon wafer reflecting surfaces at the Brewster angle, multiple linearly s-polarized side beams are generated. 3D photonic crystal structures of woodpile, Penrose quasi-crystal, and hexagonal symmetry were produced with ROEs that have 4+1, 5+1 and 6+1 beam configurations, respectively. Since the ROE design can be readily changed and implemented for different photonic crystal structures, this fabrication method is more versatile and cost effective than currently comparable single optical methods like prisms and phase masks.

  18. In situ and real time characterization of interface microstructure in 3D alloy solidification: benchmark microgravity experiments in the DECLIC-Directional Solidification Insert on ISS

    NASA Astrophysics Data System (ADS)

    Ramirez, A.; Chen, L.; Bergeon, N.; Billia, B.; Gu, Jiho; Trivedi, R.

    2012-01-01

    Dynamical microstructure formation and selection during solidification processing, which has a major influence on the properties in the use of elaborated materials, occur during the growth process. In situ observation of the solid-liquid interface morphology evolution is thus necessary. On earth, convection effects dominate in bulk samples and may strongly interact with microstructure dynamics and alter pattern characterization. Series of solidification experiments with 3D cylindrical sample geometry were conducted in succinonitrile (SCN) -0.24 wt%camphor (model transparent system), in microgravity environment in the Directional Solidification Insert of the DECLIC facility of CNES (French space agency) on the International Space Station (ISS). Microgravity enabled homogeneous values of control parameters over the whole interface allowing the obtaining of homogeneous patterns suitable to get quantitative benchmark data. First analyses of the characteristics of the pattern (spacing, order, etc.) and of its dynamics in microgravity will be presented.

  19. Strain Anisotropies and Self-limiting Capacities in Single-crystalline 3D Silicon Microstructures: Models for High Energy Denisty Lithium-Ion Battery Anodes

    SciTech Connect

    Goldman, Jason L.; Long, Brandon R.; Gewirth, Andrew A.; Nuzzo, Ralph G

    2011-01-01

    This study examines the crystallographic anisotropy of strain evolution in model, single-crystalline silicon anode microstructures on electrochemical intercalation of lithium atoms. The 3D hierarchically patterned single- crystalline silicon microstructures used as model anodes were prepared using combined methods of photolithography and anisotropic dry and wet chemical etching. Silicon anodes, which possesses theoretically ten times the energy density by weight compared to conventional carbon anodes, reveal highly anisotropic but more importantly, variably recoverable crystallographic strains during cycling. Model strain-limiting silicon anode architectures that mitigate these impacts are highlighted. By selecting a specific design for the silicon anode microstructure, and exploiting the crystallographic anisotropy of strain evolution upon lithium intercalation to control the direction of volumetric expansion, the volume available for expansion and thus the charging capacity of these structures can be broadly varied. We highlight exemplary design rules for this self-strain-limited charging in which an anode can be variably optimized between capacity and stability. Strain-limited capacities ranging from 677 mAhg-1 to 2833 mAhg-1 were achieved by constraining the area available for volumetric expansion via the design rules of the microstructures.

  20. Solidification of Al Alloys Under Electromagnetic Pulses and Characterization of the 3D Microstructures Using Synchrotron X-ray Tomography

    NASA Astrophysics Data System (ADS)

    Manuwong, Theerapatt; Zhang, Wei; Kazinczi, Peter Lobo; Bodey, Andrew J.; Rau, Christoph; Mi, Jiawei

    2015-07-01

    A novel programmable electromagnetic pulse device was developed and used to study the solidification of Al-15 pct Cu and Al-35 pct Cu alloys. The pulsed magnetic fluxes and Lorentz forces generated inside the solidifying melts were simulated using finite element methods, and their effects on the solidification microstructures were characterized using electron microscopy and synchrotron X-ray tomography. Using a discharging voltage of 120 V, a pulsed magnetic field with the peak Lorentz force of ~1.6 N was generated inside the solidifying Al-Cu melts which were showed sufficiently enough to disrupt the growth of the primary Al dendrites and the Al2Cu intermetallic phases. The microstructures exhibit a strong correlation to the characteristics of the applied pulse, forming a periodical pattern that resonates the frequency of the applied electromagnetic field.

  1. Femtosecond laser fabrication of gold nanorod/polymer composite microstructures

    NASA Astrophysics Data System (ADS)

    Masui, Kyoko; Shoji, Satoru; Ushiba, Shota; Duan, Xuan-Ming; Kawata, Satoshi

    2012-10-01

    We present a fabrication method of gold nanorod/ polymer composite microstructures by means of a femtosecond near-infrared laser light. The mechanism of this method is based on a cooperation of two optical reactions; two-photon polymerization (TPP) reaction only at the surface of gold nanorods, and optical accumulation of gold nanorods in photo-polymerizable resin. Gold nanorods were mass-produced by seed mediated growth method, and were mono-dispersed in photo-resin. The wavelength of the laser light was tuned resonant to two-photon absorption of the photo-resin, and also close to a longitudinal local surface plasmon resonance (LSPR) mode of the gold nanorods. The laser light excited LSPR onto gold nanorods, resulting in the formation of thin polymer layer only at their surface through TPP. Concurrently occurring optical accumulation of gold nanorods by continuous irradiation of laser light, gold nanorods got together into focus spot. The TPP layer at the surface of gold nanorods worked as a glue to stick one another for forming their aggregated structure in micro/nano scale. By controlling the intensity and the exposure time of laser light, an optimal condition was found to induce dominant polymerization without any thermal damages. The scanning of the focus spot makes it possible to create arbitrary micro/nano structures. This method has a potential to create plasmonic optical materials by controlling the alignment of gold nanorods.

  2. Laser Scanning Holographic Lithography for Flexible 3D Fabrication of Multi-Scale Integrated Nano-structures and Optical Biosensors

    PubMed Central

    Yuan, Liang (Leon); Herman, Peter R.

    2016-01-01

    Three-dimensional (3D) periodic nanostructures underpin a promising research direction on the frontiers of nanoscience and technology to generate advanced materials for exploiting novel photonic crystal (PC) and nanofluidic functionalities. However, formation of uniform and defect-free 3D periodic structures over large areas that can further integrate into multifunctional devices has remained a major challenge. Here, we introduce a laser scanning holographic method for 3D exposure in thick photoresist that combines the unique advantages of large area 3D holographic interference lithography (HIL) with the flexible patterning of laser direct writing to form both micro- and nano-structures in a single exposure step. Phase mask interference patterns accumulated over multiple overlapping scans are shown to stitch seamlessly and form uniform 3D nanostructure with beam size scaled to small 200 μm diameter. In this way, laser scanning is presented as a facile means to embed 3D PC structure within microfluidic channels for integration into an optofluidic lab-on-chip, demonstrating a new laser HIL writing approach for creating multi-scale integrated microsystems. PMID:26922872

  3. Laser Scanning Holographic Lithography for Flexible 3D Fabrication of Multi-Scale Integrated Nano-structures and Optical Biosensors.

    PubMed

    Yuan, Liang Leon; Herman, Peter R

    2016-01-01

    Three-dimensional (3D) periodic nanostructures underpin a promising research direction on the frontiers of nanoscience and technology to generate advanced materials for exploiting novel photonic crystal (PC) and nanofluidic functionalities. However, formation of uniform and defect-free 3D periodic structures over large areas that can further integrate into multifunctional devices has remained a major challenge. Here, we introduce a laser scanning holographic method for 3D exposure in thick photoresist that combines the unique advantages of large area 3D holographic interference lithography (HIL) with the flexible patterning of laser direct writing to form both micro- and nano-structures in a single exposure step. Phase mask interference patterns accumulated over multiple overlapping scans are shown to stitch seamlessly and form uniform 3D nanostructure with beam size scaled to small 200 μm diameter. In this way, laser scanning is presented as a facile means to embed 3D PC structure within microfluidic channels for integration into an optofluidic lab-on-chip, demonstrating a new laser HIL writing approach for creating multi-scale integrated microsystems. PMID:26922872

  4. Laser Scanning Holographic Lithography for Flexible 3D Fabrication of Multi-Scale Integrated Nano-structures and Optical Biosensors

    NASA Astrophysics Data System (ADS)

    Yuan, Liang (Leon); Herman, Peter R.

    2016-02-01

    Three-dimensional (3D) periodic nanostructures underpin a promising research direction on the frontiers of nanoscience and technology to generate advanced materials for exploiting novel photonic crystal (PC) and nanofluidic functionalities. However, formation of uniform and defect-free 3D periodic structures over large areas that can further integrate into multifunctional devices has remained a major challenge. Here, we introduce a laser scanning holographic method for 3D exposure in thick photoresist that combines the unique advantages of large area 3D holographic interference lithography (HIL) with the flexible patterning of laser direct writing to form both micro- and nano-structures in a single exposure step. Phase mask interference patterns accumulated over multiple overlapping scans are shown to stitch seamlessly and form uniform 3D nanostructure with beam size scaled to small 200 μm diameter. In this way, laser scanning is presented as a facile means to embed 3D PC structure within microfluidic channels for integration into an optofluidic lab-on-chip, demonstrating a new laser HIL writing approach for creating multi-scale integrated microsystems.

  5. Large Area 2D and 3D Colloidal Photonic Crystals Fabricated by a Roll-to-Roll Langmuir-Blodgett Method.

    PubMed

    Parchine, Mikhail; McGrath, Joe; Bardosova, Maria; Pemble, Martyn E

    2016-06-14

    We present our results on the fabrication of large area colloidal photonic crystals on flexible poly(ethylene terephthalate) (PET) film using a roll-to-roll Langmuir-Blodgett technique. Two-dimensional (2D) and three-dimensional (3D) colloidal photonic crystals from silica nanospheres (250 and 550 nm diameter) with a total area of up to 340 cm(2) have been fabricated in a continuous manner compatible with high volume manufacturing. In addition, the antireflective properties and structural integrity of the films have been enhanced via the use of a second roll-to-roll process, employing a slot-die coating of an optical adhesive over the photonic crystal films. Scanning electron microscopy images, atomic force microscopy images, and UV-vis optical transmission and reflection spectra of the fabricated photonic crystals are analyzed. This analysis confirms the high quality of the 2D and 3D photonic crystals fabricated by the roll-to-roll LB technique. Potential device applications of the large area 2D and 3D colloidal photonic crystals on flexible PET film are briefly reviewed. PMID:27218474

  6. SU-E-J-49: Design and Fabrication of Custom 3D Printed Phantoms for Radiation Therapy Research and Quality Assurance

    SciTech Connect

    Jenkins, C; Xing, L

    2015-06-15

    Purpose The rapid proliferation of affordable 3D printing techniques has enabled the custom fabrication of items ranging from paper weights to medical implants. This study investigates the feasibility of utilizing the technology for developing novel phantoms for use in radiation therapy quality assurance (QA) procedures. Methods A phantom for measuring the geometric parameters of linear accelerator (LINAC) on-board imaging (OBI) systems was designed using SolidWorks. The design was transferred to a 3D printer and fabricated using a fused deposition modeling (FDM) technique. Fiducials were embedded in the phantom by placing 1.6 mm diameter steel balls in predefined holes and securing them with silicone. Several MV and kV images of the phantom were collected and the visibility and geometric accuracy were evaluated. A second phantom, for use in the experimental evaluation of a high dose rate (HDR) brachytherapy dosimeter, was designed to secure several applicator needles in water. The applicator was fabricated in the same 3D printer and used for experiments. Results The general accuracy of printed parts was determined to be 0.1 mm. The cost of materials for the imaging and QA phantoms were $22 and $5 respectively. Both the plastic structure and fiducial markers of the imaging phantom were visible in MV and kV images. Fiducial marker locations were determined to be within 1mm of desired locations, with the discrepancy being attributed to the fiducial attachment process. The HDR phantom secured the applicators within 0.5 mm of the desired locations. Conclusion 3D printing offers an inexpensive method for fabricating custom phantoms for use in radiation therapy quality assurance. While the geometric accuracy of such parts is limited compared to more expensive methods, the phantoms are still highly functional and provide a unique opportunity for rapid fabrication of custom phantoms for use in radiation therapy QA and research.

  7. Microstructure and tribological properties of 3D needle-punched C/C-SiC brake composites

    NASA Astrophysics Data System (ADS)

    Xiao, Peng; Li, Zhuan; Xiong, Xiang

    2010-04-01

    Carbon fibre reinforced carbon and silicon carbide dual matrix composites (C/C-SiC) show excellent tribological properties and are promising candidates for advanced friction materials. A pressure infiltration/carbonization combined with liquid silicon infiltration was developed for fabricating C/C-SiC composites. The carbon fabric preform was fabricated with the three-dimensional needling method. In the pressure infiltration process, the carbon fibre reinforced plastic was prepared by infiltration of the fabric preform with the furan resin. Then the carbon fibre reinforced plastic was carbonized which was pyrolysed to form a porous carbon/carbon composites. Finally, the porous carbon/carbon was infiltrated with molten silicon to obtain C/C-SiC composites. The composites exhibit excellent friction behavior, including a good stability of brake, and the average dynamic μ is 0.38 and static μ is 0.50, in combination with the linear wear rate of about 5.6 μm cycle -1. Moreover, the friction surface was covered with friction film which is about 10 μm in thickness. These results show that the C/C-SiC brake composites are promising candidates for advanced brake and clutch systems.

  8. Three-dimensional (3D) microstructural characterization and quantification of reflow porosity in Sn-rich alloy/copper joints by X-ray tomography

    SciTech Connect

    Jiang Ling; Chawla, Nikhilesh; Pacheco, Mario; Noveski, Vladimir

    2011-10-15

    In this paper high resolution X-ray tomography was used to characterize reflow porosity in Sn-3.9Ag-0.7Cu/Cu solder joints. The combination of two segmentation techniques was applied for the three-dimensional (3D) visualization of pores in the joints and the quantification on the characteristics of reflow porosity, including pore size, volume fraction and morphology. The size, morphology and distribution of porosity were visualized in 3D for three different solder joints. Since the results are relatively similar for all three, only the results of one joint are presented. Solder reflow porosity was mostly spherical, segregated along the solder/Cu interface, and had an average pore size of 30 {mu}m in diameter. A few large pores (larger than 100 {mu}m in diameter) were present, some of which had lower sphericity, i.e., they were more irregular. The presence of these large pores may significantly influence the mechanical behavior of solder joints. - Highlights: {yields} Non-destructive 3D characterization and quantification of porosity in Pb-free solders by X-ray tomography {yields} Two new image analysis and reconstruction tools are presented that can be used by the community at large {yields} Pore size, volume fraction, and sphericity, is critical to understanding microstructure and modeling of these systems.

  9. Fabrication of 3D Printed Metal Structures by Use of High-Viscosity Cu Paste and a Screw Extruder

    NASA Astrophysics Data System (ADS)

    Hong, Seongik; Sanchez, Cesar; Du, Hanuel; Kim, Namsoo

    2015-03-01

    Three-dimensional (3D) printing is an important, rapidly growing industry. However, traditional 3D printing technology has problems with some materials. To solve the problem of the limited number of 3D-printable materials, high-viscosity materials and a new method for 3D printing were investigated. As an example of a high-viscosity material, Cu paste was synthesized and a screw extruder printer was developed to print the paste. As a fundamental part of the research, the viscosity of the Cu paste was measured for different Cu content. The viscosity of the paste increased with increasing Cu content. To print high-viscosity Cu paste, printing conditions were optimized. 3D structures were printed, by use of an extruder and high-viscosity metal paste with appropriate printing conditions, and then heat treated. After sintering, however, approximately 75% shrinkage of the final product was observed. To achieve less shrinkage, the packing factor of the Cu paste was increased by adding more Cu particles. The shrinkage factor decreased as the packing factor increased, and the size of final product was 77% of that expected.

  10. 3D Microfabrication Using Emulsion Mask Grayscale Photolithography Technique

    NASA Astrophysics Data System (ADS)

    Lee, Tze Pin; Mohamed, Khairudin

    2016-02-01

    Recently, the rapid development of technology such as biochips, microfluidic, micro-optical devices and micro-electromechanical-systems (MEMS) demands the capability to create complex design of three-dimensional (3D) microstructures. In order to create 3D microstructures, the traditional photolithography process often requires multiple photomasks to form 3D pattern from several stacked photoresist layers. This fabrication method is extremely time consuming, low throughput, costly and complicated to conduct for high volume manufacturing scale. On the other hand, next generation lithography such as electron beam lithography (EBL), focused ion beam lithography (FIB) and extreme ultraviolet lithography (EUV) are however too costly and the machines require expertise to setup. Therefore, the purpose of this study is to develop a simplified method in producing 3D microstructures using single grayscale emulsion mask technique. By using this grayscale fabrication method, microstructures of thickness as high as 500μm and as low as 20μm are obtained in a single photolithography exposure. Finally, the fabrication of 3D microfluidic channel has been demonstrated by using this grayscale photolithographic technique.

  11. High resolution cone beam X-ray computed tomography of 3D-microstructures of cast Al-alloys

    SciTech Connect

    Kastner, Johann; Harrer, Bernhard; Degischer, H. Peter

    2011-01-15

    X-ray computed tomography (XCT) has become a very important method for non-destructive 3D-characterisation of materials. XCT systems with cone beam geometry, micro- or nano-focus tubes and matrix detectors are increasingly used in research and non-destructive testing. Spatial resolutions down to 1 {mu}m can be reached with such XCT-systems for heterogeneities in metals with high absorption contrast. High resolution cone beam XCT is applied to five different Al-alloys: AlMg5Si7, AlCu4Mg1, AlZn6Mg2Cu2, AlZn8Mg2Cu2 and AlSi12Ni1. Up to four different types of inhomogeneities are segmented in one alloy using voxel sizes between (0.4 {mu}m){sup 3} and (2.3 {mu}m){sup 3}. Target metallography and elemental analysis by energy dispersive X-ray analysis are used to identify the inhomogeneities. The possibilities and restrictions of XCT applied to Al-alloys are discussed. AlMg5Si7 XCT-data with a voxel size of (0.4 {mu}m){sup 3} show inhomogeneities with brighter grey-values than the Al-matrix identified as elongated Fe-aluminides, and those with lower grey-values identified as pores and Mg{sub 2}Si-particles with a 'Chinese script-like' structure. Higher-absorbing interdendritic Al-Al{sub 2}Cu-eutectic regions appear brighter than the Al-dendrites in the CT-data of AlCu4Mg1 with (1.1 {mu}m){sup 3}/voxel, whereas pores > 4 {mu}m appear darker than the Al-matrix. The size and the 3D-structure of the {alpha}-Al dendrite arms with a diameter of 50-100 {mu}m are determined in samples from chill cast billets of AlCu4Mg1 and AlZn6Mg2Cu2 alloys. The irregular interdendritic regions containing eutectic segregations with Cu- and Zn-rich phases are > 5 {mu}m wide. Equally absorbing primary equi-axed Al{sub 3}(Sc, Zr) particles > 5 {mu}m are distinguished in the centres of the dendrites by the level of sphericity values. The distribution of Ni- and Fe-aluminides in a squeeze cast AlSi12Ni1-alloy is imaged with (0.4 {mu}m){sup 3}/voxel, but the Si-phase cannot be segmented.

  12. Miscibility Gap Closure, Interface Morphology, and Phase Microstructure of 3D Li(x)FePO4 Nanoparticles from Surface Wetting and Coherency Strain.

    PubMed

    Welland, Michael J; Karpeyev, Dmitry; O'Connor, Devin T; Heinonen, Olle

    2015-10-27

    We study the mesoscopic effects which modify phase-segregation in LixFePO4 nanoparticles using a multiphysics phase-field model implement on a high performance cluster. We simulate 3D spherical particles of radii from 3 to 40 nm and examine the equilibrium microstructure and voltage profiles as they depend on size and overall lithiation. The model includes anisotropic, concentration-dependent elastic moduli, misfit strain, and facet dependent surface wetting within a Cahn-Hilliard formulation. We find that the miscibility gap vanishes for particles of radius ∼5 nm, and the solubility limits change with overall particle lithiation. Surface wetting stabilizes minority phases by aligning them with energetically beneficial facets. The equilibrium voltage profile is modified by these effects in magnitude, and the length and slope of the voltage plateau during two-phase coexistence. PMID:26355590

  13. Tissue reconstruction in 3D-spheroids from rodent retina in a motion-free, bioreactor-based microstructure.

    PubMed

    Rieke, Matthias; Gottwald, Eric; Weibezahn, Karl-Friedrich; Layer, Paul Gottlob

    2008-12-01

    While conventional rotation culture-based retinal spheroids are most useful to study basic processes of retinogenesis and tissue regeneration, they are less appropriate for an easy and inexpensive mass production of histotypic 3-dimensional tissue spheroids, which will be of utmost importance for future bioengineering, e.g. for replacement of animal experimentation. Here we compared conventionally reaggregated spheroids derived from dissociated retinal cells from neonatal gerbils (Meriones unguiculatus) with spheroids cultured on a novel microscaffold cell chip (called cf-chip) in a motion-free bioreactor. Reaggregation and developmental processes leading to tissue formation, e.g. proliferation, apoptosis and differentiation were observed during the first 10 days in vitro (div). Remarkably, in each cf-chip micro-chamber, only one spheroid developed. In both culture systems, sphere sizes and proliferation rates were almost identical. However, apoptosis was only comparably high up to 5 div, but then became negligible in the cf-chip, while it up-rose again in the conventional culture. In both systems, immunohistochemical characterisation revealed the presence of Müller glia cells, of ganglion, amacrine, bipolar and horizontal cells at a highly comparable arrangement. In both systems, photoreceptors were detected only in spheroids from P3 retinae. Benefits of the chip-based 3D cell culture were a reliable sphere production at enhanced viability, the feasibility of single sphere observation during cultivation time, a high reproducibility and easy control of culture conditions. Further development of this approach should allow high-throughput systems not only for retinal but also other types of histotypic spheroids, to become suitable for environmental monitoring and biomedical diagnostics. PMID:19023488

  14. Fabrication of gold microstructures using negative photoresists doped with gold ions through two-photon excitation.

    PubMed

    Nakamura, Ryotaro; Kinashi, Kenji; Sakai, Wataru; Tsutsumi, Naoto

    2016-06-22

    The fabrication of gold microstructures was investigated using a mixture of SU-8 and gold ions using two-photon excitation induced by a femtosecond laser. Energy dispersive X-ray spectrometry, micro-X-ray diffraction and X-ray photoelectron spectroscopy were performed to analyse the resulting microstructures. Electrical conductivity was also measured. Elemental analysis showed that the fabricated structures consisted of triangular, reduced gold crystals and small amounts of cross-linked SU-8. The conductivity of the fabricated structures was four orders of magnitude lower than that of pure gold because of the cross-linked SU-8 present in the material. PMID:27297943

  15. Electrical manipulation of biological samples in glass-based electrofluidics fabricated by 3D femtosecond laser processing

    NASA Astrophysics Data System (ADS)

    Xu, Jian; Midorikawa, Katsumi; Sugioka, Koji

    2014-03-01

    Electrical manipulation of biological samples using glass-based electrofluidics fabricated by femtosecond laser, in which the microfluidic structures are integrated with microelectric components, is presented. Electro-orientation of movement of living cells with asymmetric shapes such as Euglena gracilis of aquatic microorganisms in microfluidic channels is demonstrated using the fabricated electrofluidics. By integrating the properly designed microelectrodes into microfluidic channels, the orientation direction of Euglena cells can be well controlled.

  16. Engineering Multi-scale Electrospun Structure for Integration into Architected 3-D Nanofibers for Cimex Annihilation: Fabrication and Mechanism Study

    NASA Astrophysics Data System (ADS)

    He, Shan; Zhang, Linxi; Liu, Ying; Rafailovich, Miriam; Garcia Center for Polymers at Engineered Interfaces Team

    In this study, engineered electrospun scaffolds with fibers oriented with designed curvature in three dimensions (3D) including the looped structure were developed based on the principle of electrostatic repulsion. Here we illustrate that 3D electrospun recycled polystyrene fibers could closely mimic the unique architectures of multi-direction and multi-layer nano-spiderweb. In contrast to virgin PS, the recycled PS (Dart Styrofoam) are known to contain zinc stearate which acts as a surfactant resulting in higher electrical charge and larger fiber curvature, hence, lower modulus. The surfactant, which is known to decrease the surface tension, may have also been effective at decreasing the confinement of the PS, where chain stretching was shown to occur, in response to the high surface tension at the air interface. Three dimensional flexible architecture with complex structures are shown to be necessary in order to block the motion of Cimex lectularius. Here we show how an engineered electrospun network of surfactant modified polymer fibers with calculated dimensions can be used to immobilize the insects. The mechanical response of the fibers has to be specifically tailored so that it is elastically deformed, without fracturing or flowing. Carefully controlling and tailoring the electrospinning parameters we can now utilize architected 3D nanofiber to create an environmental-friendly Cimex immobilization device which can lead to annihilation solution for all the other harmful insects.

  17. 3D finite element simulation of microstructure evolution in blade forging of Ti-6Al-4V alloy based on the internal state variable models

    NASA Astrophysics Data System (ADS)

    Luo, Jiao; Wu, Bin; Li, Miao-Quan

    2012-02-01

    The physically-based internal state variable (ISV) models were used to describe the changes of dislocation density, grain size, and flow stress in the high temperature deformation of titanium alloys in this study. The constants of the present models could be identified based on experimental results, which were conducted at deformation temperatures ranging from 1093 K to 1303 K, height reductions ranging from 20% to 60%, and the strain rates of 0.001, 0.01, 0.1, 1.0, and 10.0 s-1. The physically-based internal state variable models were implemented into the commercial finite element (FE) code. Then, a three-dimensional (3D) FE simulation system coupling of deformation, heat transfer, and microstructure evolution was developed for the blade forging of Ti-6Al-4V alloy. FE analysis was carried out to simulate the microstructure evolution in the blade forging of Ti-6Al-4V alloy. Finally, the blade forging tests of Ti-6Al-4V alloy were performed to validate the results of FE simulation. According to the tensile tests, it is seen that the mechanical properties, such as tensile strength and elongation, satisfy the application requirements well. The maximum and minimum differences between the calculated and experimental grain size of primary α phase are 11.71% and 4.23%, respectively. Thus, the industrial trials show a good agreement with FE simulation of blade forging.

  18. In Situ Investigation of the 3D Mechanical Microstructure at Nanoscale: Nano-CT Imaging Method of Local Small Region in Large Scale Sample

    PubMed Central

    Xu, Feng; Hu, Xiao-fang; Qu, Hong-yan; Kang, Dan; Xiao, Ti-qiao

    2014-01-01

    To investigate the local micro-/nanoscale region in a large scale sample, an image reconstruction method for nanometer computed tomography (nano-CT) was proposed in this paper. In the algorithm, wavelets were used to localize the filtered-backprojection (FBP) algorithm because of its space-frequency localization property. After the implementation of the algorithm, two simulation local reconstruction experiments were performed to confirm its effectiveness. Three evaluation criteria were used in the experiments to judge the quality of the reconstructed images. The experimental results showed that the algorithm proposed in this paper performed best because (1) the quality of its results had improved 20%–30% compared to the results of FBP and 10%–30% compared to the results of another wavelet algorithm; (2) the new algorithm was stable under different circumstances. Besides, an actual reconstruction experiment was performed using real projection data that had been collected in a CT experiment. Two-dimensional (2D) and three-dimensional (3D) images of the sample were reconstructed. The microstructure of the sample could be clearly observed in the reconstructed images. Since much attention has been directed towards the nano-CT technique to investigate the microstructure of materials, this new wavelet-based local tomography algorithm could be considered as a meaningful effort. PMID:24723829

  19. In situ investigation of the 3D mechanical microstructure at nanoscale: nano-CT imaging method of local small region in large scale sample.

    PubMed

    Dong, Bo; Xu, Feng; Hu, Xiao-fang; Qu, Hong-yan; Kang, Dan; Xiao, Ti-qiao

    2014-01-01

    To investigate the local micro-/nanoscale region in a large scale sample, an image reconstruction method for nanometer computed tomography (nano-CT) was proposed in this paper. In the algorithm, wavelets were used to localize the filtered-backprojection (FBP) algorithm because of its space-frequency localization property. After the implementation of the algorithm, two simulation local reconstruction experiments were performed to confirm its effectiveness. Three evaluation criteria were used in the experiments to judge the quality of the reconstructed images. The experimental results showed that the algorithm proposed in this paper performed best because (1) the quality of its results had improved 20%-30% compared to the results of FBP and 10%-30% compared to the results of another wavelet algorithm; (2) the new algorithm was stable under different circumstances. Besides, an actual reconstruction experiment was performed using real projection data that had been collected in a CT experiment. Two-dimensional (2D) and three-dimensional (3D) images of the sample were reconstructed. The microstructure of the sample could be clearly observed in the reconstructed images. Since much attention has been directed towards the nano-CT technique to investigate the microstructure of materials, this new wavelet-based local tomography algorithm could be considered as a meaningful effort. PMID:24723829

  20. 3D porous and ultralight carbon hybrid nanostructure fabricated from carbon foam covered by monolayer of nitrogen-doped carbon nanotubes for high performance supercapacitors

    NASA Astrophysics Data System (ADS)

    He, Shuijian; Hou, Haoqing; Chen, Wei

    2015-04-01

    3D porous and self-supported carbon hybrids are promising electrode materials for supercapacitor application attributed to their prominent properties such as binder-free electrode fabrication process, excellent electric conductivity and high power density etc. We present here a facile chemical vapor deposition method to fabricate a novel 3D flexible carbon hybrid nanostructure by growing a monolayer of nitrogen-doped carbon nanotubes on the skeleton of carbon foam (N-CNTs/CF) with Fe nanoparticle as catalyst. With such 3D porous, flexible and ultralight carbon nanostructure as binder-free electrode material, large surface area is available and fast ionic transport is facilitated. Moreover, the carbon-based network can provide excellent electronic conductivity. The electrochemical studies demonstrate that the supercapacitor constructed from the N-CNTs/CF hybrid exhibit high power density of 69.3 kW kg-1 and good stability with capacitance retention ration above 95% after cycled at 50 A g-1 for 5000 cycles. Therefore, the prepared porous N-CNTs/CF nanostructure is expected to be a type of excellent electrode material for electrical double layer capacitors.

  1. Hierarchical fabrication of heterojunctioned SrTiO3/TiO2 nanotubes on 3D microporous Ti substrate with enhanced photocatalytic activity and adhesive strength

    NASA Astrophysics Data System (ADS)

    Zhou, Jie; Yin, Lu; Zha, Kang; Li, Huirong; Liu, Zhiyuan; Wang, Jianxin; Duan, Ke; Feng, Bo

    2016-03-01

    Recently, construction of three-dimensional (3D) architecture and design of heterostructure have been proved to be two important approaches for improving photocatalytic (PC) properties of TiO2-based catalysts. In this work, a 3D microporous surface on Ti substrate (MPT) was prepared by simple acid etching. Then, heterojunctioned SrTiO3/TiO2 nanotubes with dominant {001} facets of anatase TiO2were successfully fabricated on MPT by combining anodization with hydrothermal treatment. The 3D microporous-patterned SrTiO3/TiO2 nanotubes heterojunction shows significantly enhanced photo-current density and ∼200% improved PC effect in degradation of Rhodamine B owing to its higher specific surface area, stronger light-harvesting ability and positive heterojunction effect in comparison with TiO2 nanotubes formed on flat Ti substrate. Moreover, the 3D microporous structure on Ti substrate improved the adhesive strength between the nanotubes layer and Ti substrate, which can be ascribed to the effective release of internal stress. Therefore, this present strategy is expected to expand the application of TiO2-based catalysts in many fields which require excellent PC properties and mechanical stability.

  2. Fabrication of Highly Stretchable Conductors Based on 3D Printed Porous Poly(dimethylsiloxane) and Conductive Carbon Nanotubes/Graphene Network.

    PubMed

    Duan, Shasha; Yang, Ke; Wang, Zhihui; Chen, Mengting; Zhang, Ling; Zhang, Hongbo; Li, Chunzhong

    2016-01-27

    The combination of carbon nanomaterial with three-dimensional (3D) porous polymer substrates has been demonstrated to be an effective approach to manufacture high-performance stretchable conductive materials (SCMs). However, it remains a challenge to fabricate 3D-structured SCMs with outstanding electrical conductivity capability under large strain in a facile way. In this work, the 3D printing technique was employed to prepare 3D porous poly(dimethylsiloxane) (O-PDMS) which was then integrated with carbon nanotubes and graphene conductive network and resulted in highly stretchable conductors (OPCG). Two types of OPCG were prepared, and it has been demonstrated that the OPCG with split-level structure exhibited both higher electrical conductivity and superior retention capability under deformations, which was illustrated by using a finite element method. The specially designed split-level OPCG is capable of sustaining both large strain and repeated deformations showing huge potential in the application of next-generation stretchable electronics. PMID:26713456

  3. Developing an Ear Prosthesis Fabricated in Polyvinylidene Fluoride by a 3D Printer with Sensory Intrinsic Properties of Pressure and Temperature

    PubMed Central

    Suaste-Gómez, Ernesto; Rodríguez-Roldán, Grissel; Reyes-Cruz, Héctor; Terán-Jiménez, Omar

    2016-01-01

    An ear prosthesis was designed in 3D computer graphics software and fabricated using a 3D printing process of polyvinylidene fluoride (PVDF) for use as a hearing aid. In addition, the prosthesis response to pressure and temperature was observed. Pyroelectric and piezoelectric properties of this ear prosthesis were investigated using an astable multivibrator circuit, as changes in PVDF permittivity were observed according to variations of pressure and temperature. The results show that this prosthesis is reliable for use under different conditions of pressure (0 Pa to 16,350 Pa) and temperature (2 °C to 90 °C). The experimental results show an almost linear and inversely proportional behavior between the stimuli of pressure and temperature with the frequency response. This 3D-printed ear prosthesis is a promising tool and has a great potentiality in the biomedical engineering field because of its ability to generate an electrical potential proportional to pressure and temperature, and it is the first time that such a device has been processed by the additive manufacturing process (3D printing). More work needs to be carried out to improve the performance, such as electrical stimulation of the nervous system, thereby extending the purpose of a prosthesis to the area of sensory perception. PMID:26959026

  4. A synergistic approach to the design, fabrication and evaluation of 3D printed micro and nano featured scaffolds for vascularized bone tissue repair

    NASA Astrophysics Data System (ADS)

    Holmes, Benjamin; Bulusu, Kartik; Plesniak, Michael; Zhang, Lijie Grace

    2016-02-01

    3D bioprinting has begun to show great promise in advancing the development of functional tissue/organ replacements. However, to realize the true potential of 3D bioprinted tissues for clinical use requires the fabrication of an interconnected and effective vascular network. Solving this challenge is critical, as human tissue relies on an adequate network of blood vessels to transport oxygen, nutrients, other chemicals, biological factors and waste, in and out of the tissue. Here, we have successfully designed and printed a series of novel 3D bone scaffolds with both bone formation supporting structures and highly interconnected 3D microvascular mimicking channels, for efficient and enhanced osteogenic bone regeneration as well as vascular cell growth. Using a chemical functionalization process, we have conjugated our samples with nano hydroxyapatite (nHA), for the creation of novel micro and nano featured devices for vascularized bone growth. We evaluated our scaffolds with mechanical testing, hydrodynamic measurements and in vitro human mesenchymal stem cell (hMSC) adhesion (4 h), proliferation (1, 3 and 5 d) and osteogenic differentiation (1, 2 and 3 weeks). These tests confirmed bone-like physical properties and vascular-like flow profiles, as well as demonstrated enhanced hMSC adhesion, proliferation and osteogenic differentiation. Additional in vitro experiments with human umbilical vein endothelial cells also demonstrated improved vascular cell growth, migration and organization on micro-nano featured scaffolds.

  5. A synergistic approach to the design, fabrication and evaluation of 3D printed micro and nano featured scaffolds for vascularized bone tissue repair.

    PubMed

    Holmes, Benjamin; Bulusu, Kartik; Plesniak, Michael; Zhang, Lijie Grace

    2016-02-12

    3D bioprinting has begun to show great promise in advancing the development of functional tissue/organ replacements. However, to realize the true potential of 3D bioprinted tissues for clinical use requires the fabrication of an interconnected and effective vascular network. Solving this challenge is critical, as human tissue relies on an adequate network of blood vessels to transport oxygen, nutrients, other chemicals, biological factors and waste, in and out of the tissue. Here, we have successfully designed and printed a series of novel 3D bone scaffolds with both bone formation supporting structures and highly interconnected 3D microvascular mimicking channels, for efficient and enhanced osteogenic bone regeneration as well as vascular cell growth. Using a chemical functionalization process, we have conjugated our samples with nano hydroxyapatite (nHA), for the creation of novel micro and nano featured devices for vascularized bone growth. We evaluated our scaffolds with mechanical testing, hydrodynamic measurements and in vitro human mesenchymal stem cell (hMSC) adhesion (4 h), proliferation (1, 3 and 5 d) and osteogenic differentiation (1, 2 and 3 weeks). These tests confirmed bone-like physical properties and vascular-like flow profiles, as well as demonstrated enhanced hMSC adhesion, proliferation and osteogenic differentiation. Additional in vitro experiments with human umbilical vein endothelial cells also demonstrated improved vascular cell growth, migration and organization on micro-nano featured scaffolds. PMID:26758780

  6. Developing an Ear Prosthesis Fabricated in Polyvinylidene Fluoride by a 3D Printer with Sensory Intrinsic Properties of Pressure and Temperature.

    PubMed

    Suaste-Gómez, Ernesto; Rodríguez-Roldán, Grissel; Reyes-Cruz, Héctor; Terán-Jiménez, Omar

    2016-01-01

    An ear prosthesis was designed in 3D computer graphics software and fabricated using a 3D printing process of polyvinylidene fluoride (PVDF) for use as a hearing aid. In addition, the prosthesis response to pressure and temperature was observed. Pyroelectric and piezoelectric properties of this ear prosthesis were investigated using an astable multivibrator circuit, as changes in PVDF permittivity were observed according to variations of pressure and temperature. The results show that this prosthesis is reliable for use under different conditions of pressure (0 Pa to 16,350 Pa) and temperature (2 °C to 90 °C). The experimental results show an almost linear and inversely proportional behavior between the stimuli of pressure and temperature with the frequency response. This 3D-printed ear prosthesis is a promising tool and has a great potentiality in the biomedical engineering field because of its ability to generate an electrical potential proportional to pressure and temperature, and it is the first time that such a device has been processed by the additive manufacturing process (3D printing). More work needs to be carried out to improve the performance, such as electrical stimulation of the nervous system, thereby extending the purpose of a prosthesis to the area of sensory perception. PMID:26959026

  7. Fabrication of high sensitivity 3D nanoSQUIDs based on a focused ion beam sculpting technique

    NASA Astrophysics Data System (ADS)

    De Leo, Natascia; Fretto, Matteo; Lacquaniti, Vincenzo; Granata, Carmine; Vettoliere, Antonio

    2016-09-01

    In this paper a nanofabrication process, based on a focused ion beam (FIB) nanosculpting technique, for high sensitivity three-dimensional nanoscale superconducting quantum interference devices (nanoSQUIDs) is reported. The crucial steps of the fabrication process are described, as are some peculiar features of the superconductor–normal metal–insulator–superconductor (SNIS) Josephson junctions, which may useful for applications in cryocooler systems. This fabrication procedure is employed to fabricate sandwich nanojunctions and high sensitivity nanoSQUIDs. Specifically, the superconductive nanosensors have a rectangular loop of 1 × 0.2–0.4 μm2 interrupted by two square Nb/Al–AlO x /Nb SNIS Josephson junctions with side lengths of 0.3 μm. The characterization of a typical nanoSQUID has been carried out and a spectral density of magnetic flux noise as low as 0.8 μΦ0 Hz–1/2 has been measured.

  8. Fabrication and characterization of a magnetic micro-actuator based on deformable Fe-doped PDMS artificial cilium using 3D printing

    NASA Astrophysics Data System (ADS)

    Liu, Fengli; Alici, Gursel; Zhang, Binbin; Beirne, Stephen; Li, Weihua

    2015-03-01

    This paper proposes the use of a 3D extrusion printer to fabricate artificial magnetic cilium. The cilia are fabricated using polydimethylsiloxane (PDMS) doped with iron particles so that they remain slender and flexible. They can be driven by a magnetic field to closely mimic the behaviour of biological cilia. Doping iron particles to the polymers has already been done; however, to the best of our knowledge, printing such active and soft magnetic structures has not. The existing methods for manufacturing magnetic polymeric structures are complex and difficult to use for the fabrication of micro-sized high-aspect-ratio cilia. The 3D printing technique we propose here is simple and inexpensive compared to previously suggested fabrication methods. In this study, free-standing magnetic PDMS cilia were fabricated in different sizes up to 5 mm in length and 1 mm in width. The stress-strain curves of the PDMS cilia were experimentally obtained to quantify the effect of the concentration of the iron particles on the modulus of elasticity of the cilia. The higher the iron concentration, the higher the modulus of elasticity. We have quantified the characteristics of the cilia made of 40% w/w iron particles in PDMS. A single cilium (5 × 1 × 0.0035 mm) can output up to 27 μN blocking force under a magnetic field of 160 mT. These cilia can be used as a mixer in lap-on-chip applications and as the anchoring and propulsion legs of endoscopic capsule robots operating within the gastrointestinal tract of humans. Analytical expressions estimating the blocking force are established and compared with the experimental results.

  9. Fabrication of Very-High-Aspect-Ratio Microstructures in Complex Patterns by Photoelectrochemical Etching

    SciTech Connect

    Sun, GY; Zhao, X; Kim, CJ

    2012-12-01

    We have fabricated very-high-aspect-ratio (VHAR) silicon and metal microstructures in complex geometric patterns. The recently developed surfactant-added tetramethylammonium hydroxide etching allows the formation of V-grooves in any pattern, i.e., not limited by the crystal direction, on a silicon surface. As the resulting sharp pits allow very deep photoelectrochemical etching, VHAR silicon microstructures (4-mu m-wide and over-300-mu m-deep trenches) are successfully fabricated in complex patterns (spiral and zigzag demonstrated), overcoming the prevailing limitations of simple pores and straight trenches. Furthermore, by filling the VHAR silicon mold with nickel and removing the silicon, high-aspect-ratio metal microstructures of complex patterns are also obtained. These VHAR microstructures in complex patterns, which are structurally much stronger than the simple posts and straight plates, overcome the stiction problem even when densely populated. [2012-0042

  10. Effect of cold plasma pre-treatment on photocatalytic activity of 3D fabric loaded with nano-photocatalysts: Response surface methodology

    NASA Astrophysics Data System (ADS)

    Ghoreishian, Seyed Majid; Badii, Khashayar; Norouzi, Mohammad; Malek, Kaveh

    2016-03-01

    In this study, the physico-chemical effects occasioned by the cold plasma discharge (CPD) on the photo-decolorization of Reactive Orange 16 (RO16) by 3D fabrics (spacer fabrics) loaded with ZnO:TiO2 nano-photocatalysts (nphs) were optimized via response surface methodology (RSM). CPD was employed to improve the surface characteristics of the spacer fabrics for nphs loading. Surface morphology and color variation were studied utilizing scanning electron microscopy (SEM) and CIE-Lab system, respectively. The effect of CPD on the wetting ability of the spacer fabrics was examined using dynamic adsorption measurement (DAM). Also, X-ray fluorescence (XRF) was utilized to investigate the durability of the nphs on the spacer fabrics. All the experiments were implemented in a Box-Behnken design (BBD) with three independent variables (CPD treatment time, dye concentration and irradiation time) in order to optimize the decolorization of RO16. The anticipated values of the decolorization efficiency were found to be in excellent agreement with the experimental values (R2 = 0.9996, Adjusted R2 = 0.9992). The kinetic analysis demonstrated that the photocatalytic decolorization followed the Langmuir-Hinshelwood kinetic model. In conclusion, this heterogeneous photocatalytic process is capable of decolorizing and mineralizing azoic reactive dye in textile wastewater. Moreover, the results confirmed that RSM based on the BBD was a suitable method to optimize the operating conditions of RO16 degradation.

  11. Hierarchical graphene nanocones over 3D platform of carbon fabrics: A route towards fully foldable graphene based electron source

    NASA Astrophysics Data System (ADS)

    Maiti, Uday N.; Maiti, Soumen; Das, Nirmalya S.; Chattopadhyay, Kalyan K.

    2011-10-01

    A three dimensional field emitter comprising hierarchical nanostructures of graphene over flexible fabric substrate is presented. The nanostructuring is realized through plasma treatment of graphene, coaxially deposited over individual carbon fiber by means of simple aqueous phase electrophoretic deposition technique. Hierarchical graphene nanocone, acting as a cold electron emitter, exhibits outstanding electron emission performance with a turn-on field as low as 0.41 V μm-1 and a threshold field down to 0.81 V μm-1. Electric field modification around the special woven like geometry of the underlying base fabric substrate serves as the booster to the nanostructured graphene related field amplification at the electron emission site. Superb robustness in the emission stability can be attributed to suppressed joule heating on behalf of higher inborn accessible surface area of graphene nanocone as well as excellent electrical and thermal conductivity of both the graphene and carbon fabrics. Superior flexibility of this high-performance graphene based emitter ensures their potential use in completely foldable and wearable field emission devices.A three dimensional field emitter comprising hierarchical nanostructures of graphene over flexible fabric substrate is presented. The nanostructuring is realized through plasma treatment of graphene, coaxially deposited over individual carbon fiber by means of simple aqueous phase electrophoretic deposition technique. Hierarchical graphene nanocone, acting as a cold electron emitter, exhibits outstanding electron emission performance with a turn-on field as low as 0.41 V μm-1 and a threshold field down to 0.81 V μm-1. Electric field modification around the special woven like geometry of the underlying base fabric substrate serves as the booster to the nanostructured graphene related field amplification at the electron emission site. Superb robustness in the emission stability can be attributed to suppressed joule heating on

  12. Fabrication of 3D hierarchical MoS₂/polyaniline and MoS₂/C architectures for lithium-ion battery applications.

    PubMed

    Hu, Lianren; Ren, Yumei; Yang, Hongxia; Xu, Qun

    2014-08-27

    In this work, three-dimensional (3D) hierarchical MoS2/polyaniline (PANI) nanoflowers were successfully fabricated via a simple hydrothermal method. The crystal structure and morphology of the MoS2/PANI nanoflowers were characterized by SEM, TEM, XRD, XPS, and FT-IR spectra, revealing that the nanoflowers were composed of ultrathin nanoplates which consisted of few-layered MoS2 nanosheets with enlarged interlayer distance of the (002) plane and PANI. The excellent electrochemical performance of the 3D hierarchical MoS2/PANI nanoflowers was demonstrated. Further 3D hierarchical MoS2/C nanoflowers can be prepared conveniently by annealing the MoS2/PANI sample in a N2 atmosphere at 500 °C for 4 h. The obtained MoS2/C sample exhibited more excellent electrochemical performance due to its excellent electronic conductivity resulting from the close integration of MoS2 nanosheets with carbon matrix. High reversible capacity of 888.1 mAh g(-1) with the Coulombic efficiency maintained at above 90% from the first cycle were achieved at a current density of 100 mA g(-1). Even at a current density of 1000 mA g(-1), the reversible capacity of the MoS2/C sample could be retained at 511 mAh g(-1). The excellent electrochemical performance of these two samples could be attributed to the combined action of enlarged interlayer distance of the ultrathin MoS2 nanosheets, 3D architectures, hierarchical structures, and conductive material. Thus, these 3D hierarchical nanoflowers are competent as promising anode materials for high-performance lithium-ion batteries. PMID:25100439

  13. Development of an Efficient Quasi-3D Microfluidic Flow Model and Fabrication and Characterization of an All-PDMS Opto-Microfluidic Flow Cytometer

    NASA Astrophysics Data System (ADS)

    Islam, Md Zahurul

    In this thesis, development of a novel microfluidic flow model, and, fabrication and testing of microfluidic cytometer for potential cell detection and sorting applications are described. The model is formulated by decomposing the flow profile along the height of microfluidic device into a Fourier series that converts the 3D flow equations into a series of coupled 2D equations and is applicable to planar microfluidic devices only. It is validated against the analytical solution for flow in a straight rectangular channel and the full 3D solution of a commercial Navier-Stokes solver for flow in a T-channel. Comparable accuracy to the full 3D numerical solution is achieved by using only three Fourier terms with significant decrease in computation time. The model is also extended to the problems with time-varying boundary conditions. We fabricated two first generation miniaturized cytometer prototypes and used them for preliminary proof-of-concepts experiments. They were built by cutting fluidic channels into two different polymer materials and bonding them between two standard glass slides with epoxy and fusion bonding. We fabricated a second generation of flow cytometer chip consisting of an integrated 2D hydrodynamic focusing system, solid-core optical waveguides and a hydrodynamic side-flow switching system on an all-PDMS platform. Optical propagation losses of the integrated waveguides and signal-to-noise ratio (SNR) of its detection system were characterized. The propagation losses were found to be 1.6 and 1.5 dB/cm for the green and red light, respectively. Detection of fluorescent signal through the waveguide yielded improved SNR than the conventional method of under-chip detection. Fluid flow speeds were estimated from volumetric flow measurements and fluorescent particle tracking experiments and the width of the hydrodynamically focused stream was extracted from microscope flow images. The results were compared to the simulation values obtained from the Q3D

  14. Third-harmonic generation imaging of three-dimensional microstructures fabricated by photopolymerization.

    PubMed

    Kunwar, Puskal; Toivonen, Juha; Kauranen, Martti; Bautista, Godofredo

    2016-05-01

    We demonstrate the capability of polarized third-harmonic generation (THG) for high contrast imaging of three-dimensional microstructures fabricated by photopolymerization. Using circular polarization of fundamental light, background-free optically-sectioned THG images were obtained from laser-written photopolymerized microstructures. The technique has great potential for simple and noninvasive characterization of photopolymerized devices, which typically show poor contrast in conventional light microscopy. PMID:27137551

  15. Flexible Fabrication of Shape-Controlled Collagen Building Blocks for Self-Assembly of 3D Microtissues.

    PubMed

    Zhang, Xu; Meng, Zhaoxu; Ma, Jingyun; Shi, Yang; Xu, Hui; Lykkemark, Simon; Qin, Jianhua

    2015-08-12

    Creating artificial tissue-like structures that possess the functionality, specificity, and architecture of native tissues remains a big challenge. A new and straightforward strategy for generating shape-controlled collagen building blocks with a well-defined architecture is presented, which can be used for self-assembly of complex 3D microtissues. Collagen blocks with tunable geometries are controllably produced and released via a membrane-templated microdevice. The formation of functional microtissues by embedding tissue-specific cells into collagen blocks with expression of specific proteins is described. The spontaneous self-assembly of cell-laden collagen blocks into organized tissue constructs with predetermined configurations is demonstrated, which are largely driven by the synergistic effects of cell-cell and cell-matrix interactions. This new strategy would open up new avenues for the study of tissue/organ morphogenesis, and tissue engineering applications. PMID:25920010

  16. Spring Characteristics of Circular Arc Shaped 3D Micro-cantilevers Fabricated Using III-V Semiconductor Strain-driven Bending Process

    NASA Astrophysics Data System (ADS)

    Sasaki, T. K.; Iwase, H.; Wang, J.; Akabori, M.; Yamada, S.

    2011-12-01

    We have investigated the characteristics of the circular arc shaped 3D micro-cantilever. The cantilever was fabricated using strain driven self-bending process based on the epitaxial growth. The arc shape can be used as the spring element in the various micro electro- mechanical- system (MEMS) applications. In this work, we focused on the force-deflection relationships, which would give the spring constant of the arc spring. In the case of the arc spring, spring constant depends on the dimensional parameters such as width, thickness and curvature radius. From the dependence of curvature radius on width, there seems no stress relaxation in width direction (transverse to deformation direction). Moreover, the measured spring constants of the fabricated cantilevers were also larger than the estimated ones from the curvature radius. The discrepancy indicates a possibility of stiffness enhancement of the circular arc shaped cantilevers.

  17. Fabrication of PDMS (poly-dimethyl siloxane) molding and 3D structure by two-photon absorption induced by an ultrafast laser

    NASA Astrophysics Data System (ADS)

    Yi, Shin Wook; Lee, Seong Ku; Cho, Mi Jung; Kong, Hong Jin; Yang, Dong-Yol; Park, Sang-hu; Lim, Tae-woo; Kim, Ran Hee; Lee, Kwang-Sup

    2004-12-01

    Multi-photon absorption phenomena induced by ultra fast laser have been considered for many applications of microfabrications such as metal ablation, glass etching and photopolymerization. Among the applications, the photopolymerization by two-photon absorption (TPA) has been regarded as a new microfabricating method. It is possible to be used in photo mask correcting, diffractive optical element and micro machining. The TPA photopolymerization is made possible to fabricate a complicated three dimensional structure which the conventional photomask technology has not been able to make. Furthermore the TPA photopolymerization process applied to a two dimensional structure fabrication may take shorter time than the old process since the absence of etching and deposition processes. Recently we have made a simple 3D structure and applied the technique to PDMS(poly-dimethyl siloxane) molding.

  18. About the relationship between microstructural and effective physical properties of snow computed on 3D images: comparison with measurements and models (Invited)

    NASA Astrophysics Data System (ADS)

    Calonne, N.; Geindreau, C.; Flin, F.; Lesaffre, B.; Rolland du Roscoat, S.

    2013-12-01

    The determination of accurate macroscopic effective properties of snow is critical for several topics related to cryospheric sciences such as climate modelling, hydrology or avalanche forecasting. Among different approaches, the upscaling methods allow to estimate the macroscopic behaviours from microscopic information of the medium, provided that the condition of separation of scales is satisfied. This condition reads l / L << 1 where l and L are the characteristic lengths of the heterogeneities at the pore scale and of the macroscopic sample or excitation, respectively. It implies the existence of a Representative Elementary Volume (REV) of size l for the material and the considered physical phenomenon from which effective properties can be defined. For 15 years, several X-ray tomographic acquisitions have been performed leading to a set of 3D images of snow representative of a wide range of snow types coming from cold-room experiments or field collections. In the present work, some effective properties of snow were computed in the x-, y- and z-direction by solving, over REVs extracted from the above 3D images, a specific boundary values problem arising from the upscaling process. The effective properties under consideration are the effective thermal conductivity tensor, the air permeability tensor and the effective diffusion tensor which is intimately related to the tortuosity tensor of the air phase (Calonne et al., 2011, 2012). In addition, several structural properties, such as the porosity, the correlation length, the specific surface area were also computed on REVs using classical algorithms of image analysis. The relationship between microstructure and the effective properties were then analysed, as well as their anisotropy. Our results are also compared with measurements and analytical models. They show that analytical models based on a simple description of the microstructure (density, ellipsoids shape) succeed to capture the main features of snow

  19. The design and fabrication of a toroidally continuous cryocondensation pump for the D3-D advanced divertor

    NASA Astrophysics Data System (ADS)

    Smith, J. P.; Baxi, C. B.; Reis, E.; Schaffer, M. J.; Schaubel, K. M.; Menon, M. M.

    1991-11-01

    A cryocondensation pump will be installed in the baffle chamber of the DIII-D tokamak in the spring of 1992. The design is complete and fabrication of this pump is in progress. The purpose of the pump is to study plasma density control by pumping the divertor. The pump is toroidally continuous, approximately 10 m long, in the lower outer corner of the vacuum vessel interior. It consists of a 1 m(exp 2) liquid helium cooled surface surrounded by a liquid nitrogen cooled shield to limit the heat load on the helium cooled surface. The stainless steel liquid nitrogen shell has a copper coating on it to enhance thermal conductivity, but the coating is broken to keep the toroidal electrical resistance high. The liquid nitrogen cooled surface is surrounded by a radiation/particle shield to prevent energetic particles from impacting and releasing condensed water molecules. The whole pump is supported off the water cooled vacuum vessel wall. Key design considerations were: how to accommodate the temperature differences between the various components, developing low heat leak paths for the various supports, and maintaining electrical insulation in a low pressure environment in the presence of induced voltage spikes. A single point ground for the system was used to limit disruption induced currents and the resulting electro-mechanical forces on the pump. A testing program was used to develop coating techniques to enhance heat transfer and emissivity of the various surfaces. Fabrication tests were done to determine the best method of attaching the liquid nitrogen flow tubes to their shield surfaces. A prototype sector of the pump was built to verify fabrication and assembly techniques.

  20. 3D Printing, Additive Manufacturing, and Solid Freeform Fabrication: The Technologies of the Past, Present and Future

    NASA Astrophysics Data System (ADS)

    Beaman, Joseph

    2015-03-01

    Starting in the late 1980's, several new technologies were created that have the potential to revolutionize manufacturing. These technologies are, for the most part, additive processes that build up parts layer by layer. In addition, the processes that are being touted for hard-core manufacturing are primarily laser or e-beam based processes. This presentation gives a brief history of Additive Manufacturing and gives an assessment for these technologies. These technologies initially grew out of a commercial need for rapid prototyping. This market has a different requirement for process and quality control than traditional manufacturing. The relatively poor process control of the existing commercial Additive Manufacturing equipment is a vestige of this history. This presentation discusses this history and improvements in quality over time. The emphasis will be on Additive Manufacturing processes that are being considered for direct manufacturing, which is a different market than the 3D Printing ``Makerbot'' market. Topics discussed include past and present machine sensors, materials, and operational methods that were used in the past and those that are used today to create manufactured parts. Finally, a discussion of new methods and future directions of AM is presented.

  1. Mechanical and in vitro performance of apatite-wollastonite glass ceramic reinforced hydroxyapatite composite fabricated by 3D-printing.

    PubMed

    Suwanprateeb, J; Sanngam, R; Suvannapruk, W; Panyathanmaporn, T

    2009-06-01

    In situ hydroxyapatite/apatite-wollastonite glass ceramic composite was fabricated by a three dimensional printing (3DP) technique and characterized. It was found that the as-fabricated mean green strength of the composite was 1.27 MPa which was sufficient for general handling. After varying sintering temperatures (1050-1300 degrees C) and times (1-10 h), it was found that sintering at 1300 degrees C for 3 h gave the greatest flexural modulus and strength, 34.10 GPa and 76.82 MPa respectively. This was associated with a decrease in porosity and increase in densification ability of the composite resulting from liquid phase sintering. Bioactivity tested by soaking in simulated body fluid (SBF) and In Vitro toxicity studies showed that 3DP hydroxyapatite/A-W glass ceramic composite was non-toxic and bioactive. A new calcium phosphate layer was observed on the surface of the composite after soaking in SBF for only 1 day while osteoblast cells were able to attach and attain normal morphology on the surface of the composite. PMID:19225870

  2. The fabrication of foam-like 3D mesoporous NiO-Ni as anode for high performance Li-ion batteries

    SciTech Connect

    Huang, Peng; Zhang, Xin; Wei, Jumeng; Pan, Jiaqi; Sheng, Yingzhou; Feng, Boxue

    2015-03-15

    Graphical abstract: Foam-like 3 dimensional (3D) mesoporous NiO on 3D micro-porous Ni was fabricated. - Highlights: • We prepare NiO-Ni foam composite via hydrothermal etching and subsequent annealing. • The NiO exhibits novel foam-like 3D mesoporous architecture. • The NiO-Ni anode shows good cycle stability. - Abstract: Foam-like three dimensional mesoporous NiO on Ni foam was fabricated via facile hydrothermal etching and subsequent annealing treatment. The porous NiO consists of a large number of nanosheets with mean thickness about 50 nm, among which a large number of mesoscopic pores with size ranges from 100 nm to 1 μm distribute. The electrochemical performance of the as-prepared NiO-Ni as anode for lithium ion battery was studied by conventional charge/discharge test, which shows excellent cycle stability and rate capability. It exhibits initial discharge and charge capacities of 979 and 707 mA h g{sup −1} at a charge/discharge rate of 0.7 C, which maintain of 747 and 738 mA h g{sup −1} after 100 cycles. Even after 60 cycles at various rates from 0.06 to 14 C, the 10th discharge and charge capacities of the NiO-Ni electrode can revert to 699 and 683 mA h g{sup −1} when lowering the charge/discharge rate to 0.06 C.

  3. WE-F-16A-02: Design, Fabrication, and Validation of a 3D-Printed Proton Filter for Range Spreading

    SciTech Connect

    Remmes, N; Courneyea, L; Corner, S; Beltran, C; Kemp, B; Kruse, J; Herman, M; Stoker, J

    2014-06-15

    Purpose: To design, fabricate and test a 3D-printed filter for proton range spreading in scanned proton beams. The narrow Bragg peak in lower-energy synchrotron-based scanned proton beams can result in longer treatment times for shallow targets due to energy switching time and plan quality degradation due to minimum monitor unit limitations. A filter with variable thicknesses patterned on the same scale as the beam's lateral spot size will widen the Bragg peak. Methods: The filter consists of pyramids dimensioned to have a Gaussian distribution in thickness. The pyramids are 2.5mm wide at the base, 0.6 mm wide at the peak, 5mm tall, and are repeated in a 2.5mm pseudo-hexagonal lattice. Monte Carlo simulations of the filter in a proton beam were run using TOPAS to assess the change in depth profiles and lateral beam profiles. The prototypes were constrained to a 2.5cm diameter disk to allow for micro-CT imaging of promising prototypes. Three different 3D printers were tested. Depth-doses with and without the prototype filter were then measured in a ~70MeV proton beam using a multilayer ion chamber. Results: The simulation results were consistent with design expectations. Prototypes printed on one printer were clearly unacceptable on visual inspection. Prototypes on a second printer looked acceptable, but the micro-CT image showed unacceptable voids within the pyramids. Prototypes from the third printer appeared acceptable visually and on micro-CT imaging. Depth dose scans using the prototype from the third printer were consistent with simulation results. Bragg peak width increased by about 3x. Conclusions: A prototype 3D printer pyramid filter for range spreading was successfully designed, fabricated and tested. The filter has greater design flexibility and lower prototyping and production costs compared to traditional ridge filters. Printer and material selection played a large role in the successful development of the filter.

  4. Fabrication of selective injection microstructured optical fibers with a conventional fusion splicer.

    PubMed

    Xiao, Limin; Jin, Wei; Demokan, M; Ho, Hoi; Hoo, Yeuk; Zhao, Chunliu

    2005-10-31

    A simple method for fabricating selective injection microstructured optical fibers (MOFs) using a conventional fusion splicer is described. The effects of fusion current, fusion duration and offset position on the hole collapse property of the MOFs are investigated. With this method, the central hollow-core and the holes in the cladding region can be selectively infiltrated, which allows for the fabrication of novel hybrid polymer-silica and liquid-silica MOFs for various applications. PMID:19498936

  5. Evolution of microstructure during fabrication of Zr-2.5 wt pct Nb ally pressure tubes

    SciTech Connect

    Srivastava, D.; Dey, G.K.; Banerjee, S.

    1995-10-01

    Microstructural changes occurring during the fabrication of Zr-2.5 pct Nb alloy pressure tubes by a modified route, involving hot extrusion followed by two pilgering operations with an intermediate annealing step, have been examined in detail. In the conventional fabrication route, the hot extrusion step is followed by a single cold drawing operation in which the cold work to the extent of 25 pct is imparted to the material for achieving the required mechanical properties. Tensile properties obtained at each stage of fabrication have been evaluated and compared between the two processes. The main aim of this work has been to produce a microstructure and texture which are know n to yield a lower irradiation growth. Additionally, suitable annealing conditions have been optimized for the intermediate annealing which annihilates the cold work introduced by the first cold pilgering operation without disturbing the two-phase elongated microstructure. This elongated {alpha} + {beta}{sub I} microstructure is required for obtaining the desired level of strength at 310 C. The final microstructure and the crystallographic texture of the finished pressure tube have been compared with those reported for the conventionally processed material.

  6. Fabrication of Compositionally and Topographically Complex Robust Tissue Forms by 3D-Electrochemical Compaction of Collagen

    PubMed Central

    Younesi, Mousa; Islam, Anowarul; Kishore, Vipuil; Panit, Stefi; Akkus, Ozan

    2015-01-01

    Collagen solutions are phase-transformed to mechanically robust shell structures with curviplanar topographies using electrochemically induced pH gradients. The process enables rapid layer-by-layer deposition of collagen-rich mixtures over the entire field simultaneously to obtain compositionally diverse multilayered structures. In-plane tensile strength and modulus of the electrocompacted collagen sheet samples were 5200 -fold and 2300 -fold greater than that of uncompacted collagen samples. Out of plane compression tests showed 27 -fold and fold increase in compressive stress and 46 -fold increase in compressive modulus compared to uncompacted collagen sheets. Cells proliferated 4.9 times faster, and cellular area spread was 2.7 times greater on compacted collagen sheets. Electrocompaction also resulted in 2.9 times greater focal adhesion area than on regular collagen hydrogel. The reported improvements in the cell-matrix interactions with electrocompaction would serve to expedite the population of electrocompacted collagen scaffolds by cells. The capacity of the method to fabricate nonlinear curved topographies with compositional heterogeneous layers is demonstrated by sequential deposition of collagenhydroxyapatite layer over a collagen layer. The complex curved topography of the nasal structure is replicated by the electrochemical compaction method. The presented electrochemical compaction process is an enabling modality which holds significant promise for reconstruction of a wide spectrum of topographically complex systems such as joint surfaces, craniofacial defects, ears, nose or urogenital forms. PMID:26069162

  7. Microstructure fabrication process induced modulations in CVD graphene

    SciTech Connect

    Matsubayashi, Akitomo Zhang, Zhenjun; Lee, Ji Ung; LaBella, Vincent P.

    2014-12-15

    The systematic Raman spectroscopic study of a “mimicked” graphene device fabrication is presented. Upon photoresist baking, compressive stress is induced in the graphene which disappears after it is removed. The indirect irradiation from the electron beam (through the photoresist) does not significantly alter graphene characteristic Raman peaks indicating that graphene quality is preserved upon the exposure. The 2D peak shifts and the intensity ratio of 2D and G band, I(2D)/I(G), decreases upon direct metal deposition (Co and Py) suggesting that the electronic modulation occurs due to sp{sup 2} C-C bond weakening. In contrast, a thin metal oxide film deposited graphene does not show either the significant 2D and G peaks shift or I(2D)/I(G) decrease upon the metal deposition suggesting the oxide protect the graphene quality in the fabrication process.

  8. A microfluidic opto-caloric switch for sorting of particles by using 3D-hydrodynamic focusing based on SLE fabrication capabilities.

    PubMed

    Meineke, G; Hermans, M; Klos, J; Lenenbach, A; Noll, R

    2016-03-01

    In a miniaturised flow switch fluid flows are controlled by reducing the local viscosity via absorption of laser radiation. Through this, the local flow rates are increased to switch the outlet port of a fluid flow carrying the analyte. The microfluidic chip is fabricated using Selective Laser-Induced Etching (SLE). SLE allows novel 3D-hydrodynamic focusing, realising circular shaped channel cross-sections and adapting interaction volume geometries to the profile of the laser radiation for optimised absorption. The performance of the switch is validated experimentally with a dyed analyte and video image processing. The ability to sort particles like cells is demonstrated at 8 Hz using polystyrene beads having a diameter of 8 μm. PMID:26862603

  9. Graphene-Protected 3D Sb-based Anodes Fabricated via Electrostatic Assembly and Confinement Replacement for Enhanced Lithium and Sodium Storage.

    PubMed

    Ding, Yuan-Li; Wu, Chao; Kopold, Peter; van Aken, Peter A; Maier, Joachim; Yu, Yan

    2015-12-01

    Alloy anodes have shown great potential for next-generation lithium-ion batteries (LIBs) and sodium-ion batteries (SIBs). However, these applications are still limited by inherent huge volume changes and sluggish kinetics. To overcome such limitations, graphene-protected 3D Sb-based anodes grown on conductive substrate are designed and fabricated by a facile electrostatic-assembling and subsequent confinement replacement strategy. As binder-free anodes for LIBs, the obtained electrode exhibits reversible capacities of 442 mAh g(-1) at 100 mA g(-1) and 295 mAh g(-1) at 1000 mA g(-1), and a capacity retention of above 90% (based on the 10th cycle) after 200 cycles at 500 mA g(-1). As for sodium storage properties, the reversible capacities of 517 mAh g(-1) at 50 mA g(-1) and 315 mAh g(-1) at 1000 mA g(-1), the capacity retention of 305 mAh g(-1) after 100 cycles at 300 mA g(-1) are obtained, respectively. Furthermore, the 3D architecture retains good structural integrity after cycling, confirming that the introduction of high-stretchy and robust graphene layers can effectively buffer alloying anodes, and simultaneously provide sustainable contact and protection of the active materials. Such findings show its great potential as superior binder-free anodes for LIBs and SIBs. PMID:26456169

  10. Design and fabrication of a microstructured bifocal intraocular lens

    NASA Astrophysics Data System (ADS)

    Stork, Wilhelm; Wagner, Armin; Kreiner, Christine F.; Mueller-Glaser, Klaus-Dieter

    1999-06-01

    Intraocular lenses IOLs allow the vision restoration of cataract patients. However the ability of accommodation is lost after cataract surgery. Multifocal lenses show two or more foci with different refractive powers. Far and near objects can be at focus simultaneously. No additional spectacles are necessary. Bifocal lenses can be fabricated as multizone or as diffractive lenses. Diffractive multifocal lenses show in contrast to multi zone multifocal lenses no change of the brightness ratio for the far and near focus with change of the pupil diameter. Diffractive lenses show a saw tooth like microscopic shape with a geometrical height of the teeth in the order of microns. The lens was fabricated with a mold technique in a flexible silicone material. The molds have been lathed in metal with a ultra precision diamond lathe machine. For the test of the optical performance a MTF-measurement machine was constructed for multifocal lenses. With this machine the imaging quality and the intensity ratio of the two foci were measured. The optical quality of the lens turned out to be diffraction limited. At the University Hospital of Giessen, Germany a first clinical evaluation with 23 patients has been performed and proved for the high quality of the manufactured IOLs.

  11. Microstructural Architecture, Microstructures, and Mechanical Properties for a Nickel-Base Superalloy Fabricated by Electron Beam Melting

    NASA Astrophysics Data System (ADS)

    Murr, L. E.; Martinez, E.; Gaytan, S. M.; Ramirez, D. A.; Machado, B. I.; Shindo, P. W.; Martinez, J. L.; Medina, F.; Wooten, J.; Ciscel, D.; Ackelid, U.; Wicker, R. B.

    2011-11-01

    Microstructures and a microstructural, columnar architecture as well as mechanical behavior of as-fabricated and processed INCONEL alloy 625 components produced by additive manufacturing using electron beam melting (EBM) of prealloyed precursor powder are examined in this study. As-fabricated and hot-isostatically pressed ("hipped") [at 1393 K (1120 °C)] cylinders examined by optical metallography (OM), scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy-dispersive (X-ray) spectrometry (EDS), and X-ray diffraction (XRD) exhibited an initial EBM-developed γ″ (bct) Ni3Nb precipitate platelet columnar architecture within columnar [200] textured γ (fcc) Ni-Cr grains aligned in the cylinder axis, parallel to the EBM build direction. Upon annealing at 1393 K (1120 °C) (hot-isostatic press (HIP)), these precipitate columns dissolve and the columnar, γ, grains recrystallized forming generally equiaxed grains (with coherent {111} annealing twins), containing NbCr2 laves precipitates. Microindentation hardnesses decreased from 2.7 to 2.2 GPa following hot-isostatic pressing ("hipping"), and the corresponding engineering (0.2 pct) offset yield stress decreased from 0.41 to 0.33 GPa, while the UTS increased from 0.75 to 0.77 GPa. However, the corresponding elongation increased from 44 to 69 pct for the hipped components.

  12. Influence of the laser assisted fabricated 3D porous scaffolds from bioceramoplasts of micron and nano sizes on culture of MMSC

    NASA Astrophysics Data System (ADS)

    Shishkovsky, I.; Volchkov, S.

    2013-11-01

    The objective of the investigation was to test the biocompatibility of 3D porous biopolymer matrices (tissue-cellular scaffolds), made of biocompatible and bioresorbable polymers (polycarbonate, polyetheretherketone /PEEK/, polycaprolactone), including the materials with biocompatible oxide ceramics additive (TiO2, Al2O3, ZrO2 and hydroxyapatite) of micron and nano sizes, for tissue-engineering purposes. The porous samples were prepared via a layer-by-layer SLS method. The surface microstructures and their roughness were analyzed by the optical microscopy equipped with the cell analysis software. The cellular morphology, proliferative activity and adhesion of the polymeric and ceramopolymeric matrices were the subjects for comparison. The study showed that all the tested materials posessed biocompatible properties. The experimentally estimated cell duplication speed per day turned out to be maximal for polycarbonate (0.279 duplications per day) and for PEEK + Al2O3 = 3:1 group (0.30 dupl/day) against 0.387 dupl/day for the reference sample and 0.270 dupl/day for the group of cells placed close to the pure titanium samples.

  13. Three-dimensional microstructural design of woven fabric composite material by homogenization method

    SciTech Connect

    Takano, Naoki; Zako, Masaru

    1995-11-01

    The strength of woven fabric composite materials depends on the microstructural geometry. However, the conventional methods for mechanical analysis, which have been widely used so far, are insufficient because they cannot take into account for the three-dimensional microstructure. In this study, three-dimensional homogenization method is shown to be effective for the evaluations of the material constants, microscopic stresses and the strength. It has been found that the transverse stresses in the direction of lamination play an important role for the fracture of both fiber bundle and resin. Also, the effect of the mismatched lay-up on the strength has been investigated. It has well been predicted that the mismatched lay-up causes the reduction of the strength and the difference of crack initiation in the resin. These simulations give a new concept of the microstructural design of the composite materials.

  14. A measurement method of cutting tool position for relay fabrication of microstructured surface

    NASA Astrophysics Data System (ADS)

    Chen, Yuan-Liu; Gao, Wei; Ju, Bing-Feng; Shimizu, Yuki; Ito, So

    2014-06-01

    By using the secondary function of a force sensor integrated fast tool servo (FTS) for surface profile measurement, the three-dimensional tip position of a micro-cutting tool in the FTS with respect to the fabricated microstructures was measured without using any additional instrument for realizing the concept of relay fabrication of microstructured surface. It was verified from the experiments for testing the basic performances of tool tip position measurement that the delay of the force feedback control loop of the FTS was a big factor influencing the position measurement accuracy. A bidirectional scanning strategy was then employed to reduce the position measurement error due to the delay of the feedback control loop. Tool tip position measurement experiments by using micro-tools with a nose radius of 100 µm for relay fabrications with sub-micrometer accuracies, including stitching fabrication of a micro-groove line array and filling fabrication of a microlens lattice pattern, were carried out to demonstrate the feasibility of the tool position measurement method.

  15. Facile fabrication of hierarchical ZnO microstructures assisted with PAMPSA and enhancement of green emission

    NASA Astrophysics Data System (ADS)

    Huang, Qiang; Cun, Tangxiang; Zuo, Wenbin; Liu, Jianping

    2015-03-01

    We report the fabrication of hierarchically microstructured flower-like ZnO by a facile and single-step procedure involving poly(2-acrylamido-2-methyl-1-propanesulfonic acid) (PAMPSA) assisted aqueous chemical method. The shapes and sizes can be controlled just by varying the concentrations of the water-soluble polymer. When a suitable PAMPAS concentration was utilized, uniform well-defined and mono-dispersed chrysanthemum-like ZnO microstructures based on nanorod building blocks were obtained. The formation mechanism of the hierarchical structure was presented. The structured studies using XRD, HRTEM and SAED reveal these ZnO nanorods are composed of a single phase nature with wurtzite structure and grow along with the c-axis. FTIR spectrum indicated the incorporation of a trace of PAMPSA into ZnO crystals. HRTEM, Raman and XPS analyses showed that the hierarchical ZnO microstructures contain high concentration of oxygen vacancies which enable them exhibiting a significant intense deep-level emission centered at green luminescence in its photoluminescence spectra. They also show enhanced photocatalytic efficiency in degradation of methylene blue. It is hoped that the present work may provide a simple method to fabricate ZnO hierarchical microstructures and a positive relationship among polar plane, oxygen vacancy and green emission.

  16. Fabrication of microstructured fibers from preforms with sealed top-end holes

    NASA Astrophysics Data System (ADS)

    Semjonov, Sergey L.; Denisov, Alexander N.; Senatorov, Andrei K.

    2014-03-01

    Theoretical aspects of microstructured fibers fabrication from preforms with sealed holes at the top end are discussed. Dependences of the holes blowing degree on their diameters, on a ratio of the preform top end temperature to temperature in the center of a furnace and on other parameters are estimated. Experimental results of different microstructured fibers drawing in such a regime are presented. We have drawn the simplest microstructured fiber with one hole from a tube with outside diameter 6.2 mm and inner diameter 4.4 mm (capillary drawing). Also we have drawn MSFs from preforms with 6 and 60 small holes. To check the results of the theoretical analysis we have prepared a preform with different size holes and then drew it into a fiber. In all cases experimental results are in good agreement with theoretical estimations. Thus this method of fabrication gives the possibility to manufacture long length microstructured fibers with stable internal structural parameters, high reproducibility, ease of controlling and changing the fibers parameters and opportunity to make structures with holes of different sizes. The observed changes of the holes blowing degree in our experimental samples can be easily compensated with the help of additional heating of the preform top end. Besides, such heating makes it possible to control and change the holes blowing degree, particularly during the fibers drawing process.

  17. 3D microscope

    NASA Astrophysics Data System (ADS)

    Iizuka, Keigo

    2008-02-01

    In order to circumvent the fact that only one observer can view the image from a stereoscopic microscope, an attachment was devised for displaying the 3D microscopic image on a large LCD monitor for viewing by multiple observers in real time. The principle of operation, design, fabrication, and performance are presented, along with tolerance measurements relating to the properties of the cellophane half-wave plate used in the design.

  18. Bukliball and Beyond: 3-D Soft Auxetic Metamaterials

    NASA Astrophysics Data System (ADS)

    Shim, Jongmin; Babaee, Sahab; Weaver, James C.; Patel, Nikita; Chen, Elizabeth R.; Bertoldi, Katia

    2013-03-01

    We present a new class of 3-D soft metamaterials whose microstructure can be dramatically changed in response to mechanical loading. Patterned spherical shells, the Buckliballs (PNAS 109(16):5978) which undergo undergoing a buckling-induced structural transformation under pressure, are employed as building blocks, and are assembled to construct 3-D super-structures. We present procedures to guide the selection of both the building blocks and their arrangement, and design materials with tunable 3-D auxetic behavior that exploit buckling as the actuation mechanism. The validity of the proposed material design is demonstrated through both experiments and finite element simulations. This pattern transformation induced by a mechanical instability opens the possibility for fabrication of 3-D auxetic materials/structures over a wide range of length scales.

  19. Tensile Properties and Microstructure of Inconel 718 Fabricated with Electron Beam Freeform Fabrication (EBF(sup 3))

    NASA Technical Reports Server (NTRS)

    Bird, R. Keith; Hibberd, Joshua

    2009-01-01

    Electron beam freeform fabrication (EBF3) direct metal deposition processing was used to fabricate two Inconel 718 single-bead-width wall builds and one multiple-bead-width block build. Specimens were machined to evaluate microstructure and room temperature tensile properties. The tensile strength and yield strength of the as-deposited material from the wall and block builds were greater than those for conventional Inconel 718 castings but were less than those for conventional cold-rolled sheet. Ductility levels for the EBF3 material were similar to those for conventionally-processed sheet and castings. An unexpected result was that the modulus of the EBF3-deposited Inconel 718 was significantly lower than that of the conventional material. This low modulus may be associated with a preferred crystallographic orientation resultant from the deposition and rapid solidification process. A heat treatment with a high solution treatment temperature resulted in a recrystallized microstructure and an increased modulus. However, the modulus was not increased to the level that is expected for Inconel 718.

  20. Evolution and Control of 2219 Aluminum Microstructural Features through Electron Beam Freeform Fabrication

    NASA Technical Reports Server (NTRS)

    Taminger, Karen M.; Hafley, Robert A.; Domack, Marcia S.

    2006-01-01

    Electron beam freeform fabrication (EBF3) is a new layer-additive process that has been developed for near-net shape fabrication of complex structures. EBF3 uses an electron beam to create a molten pool on the surface of a substrate. Wire is fed into the molten pool and the part translated with respect to the beam to build up a 3-dimensional structure one layer at a time. Unlike many other freeform fabrication processes, the energy coupling of the electron beam is extremely well suited to processing of aluminum alloys. The layer-additive nature of the EBF3 process results in a tortuous thermal path producing complex microstructures including: small homogeneous equiaxed grains; dendritic growth contained within larger grains; and/or pervasive dendritic formation in the interpass regions of the deposits. Several process control variables contribute to the formation of these different microstructures, including translation speed, wire feed rate, beam current and accelerating voltage. In electron beam processing, higher accelerating voltages embed the energy deeper below the surface of the substrate. Two EBF3 systems have been established at NASA Langley, one with a low-voltage (10-30kV) and the other a high-voltage (30-60 kV) electron beam gun. Aluminum alloy 2219 was processed over a range of different variables to explore the design space and correlate the resultant microstructures with the processing parameters. This report is specifically exploring the impact of accelerating voltage. Of particular interest is correlating energy to the resultant material characteristics to determine the potential of achieving microstructural control through precise management of the heat flux and cooling rates during deposition.

  1. On the influence of recrystallization on snow fabric and microstructure: study of a snow profile in Central East Antarctica

    NASA Astrophysics Data System (ADS)

    Calonne, Neige; Schneebeli, Martin; Montagnat, Maurine; Matzl, Margret

    2016-04-01

    Temperature gradient metamorphism affects the Antarctic snowpack up to 5 meters depth, which lead to a recrystallization of the ice grains by sublimation of ice and deposition of water vapor. By this way, it is well known that the snow microstructure evolves (geometrical changes). Also, a recent study shows an evolution of the snow fabric, based on a cold laboratory experiment. Both fabric and microstructure are required to better understand mechanical behavior and densification of snow, firn and ice, given polar climatology. The fabric of firn and ice has been extensively investigated, but the publications by Stephenson (1967, 1968) are to our knowledge the only ones describing the snow fabric in Antarctica. In this context, our work focuses on snow microstructure and fabric in the first meters depth of the Antarctic ice sheet, where temperature gradients driven recrystallization occurs. Accurate details of the snow microstructure are observed using micro-computed tomography. Snow fabrics were measured at various depths from thin sections of impregnated snow with an Automatic Ice Texture Analyzer (AITA). A definite relationship between microstructure and fabric is found and highlights the influence of metamorphism on both properties. Our results also show that the metamorphism enhances the differences between the snow layers properties. Our work stresses the significant and complex evolution of snow properties in the upper meters of the ice sheet and opens the question of how these layer properties will evolve at depth and may influence the densification.

  2. Biological strategy for the fabrication of highly ordered aragonite helices: the microstructure of the cavolinioidean gastropods.

    PubMed

    Checa, Antonio G; Macías-Sánchez, Elena; Ramírez-Rico, Joaquín

    2016-01-01

    The Cavolinioidea are planktonic gastropods which construct their shells with the so-called aragonitic helical fibrous microstructure, consisting of a highly ordered arrangement of helically coiled interlocking continuous crystalline aragonite fibres. Our study reveals that, despite the high and continuous degree of interlocking between fibres, every fibre has a differentiated organic-rich thin external band, which is never invaded by neighbouring fibres. In this way, fibres avoid extinction. These intra-fibre organic-rich bands appear on the growth surface of the shell as minuscule elevations, which have to be secreted differentially by the outer mantle cells. We propose that, as the shell thickens during mineralization, fibre secretion proceeds by a mechanism of contact recognition and displacement of the tips along circular trajectories by the cells of the outer mantle surface. Given the sizes of the tips, this mechanism has to operate at the subcellular level. Accordingly, the fabrication of the helical microstructure is under strict biological control. This mechanism of fibre-by-fibre fabrication by the mantle cells is unlike that any other shell microstructure. PMID:27181457

  3. Microstructural and fabric studies from the rocks of the Moine Nappe, Eriboll, NW Scotland

    NASA Astrophysics Data System (ADS)

    Evans, D. J.; White, S. H.

    Microstructures and quartz c-axis fabric diagrams from mylonites and psammitic Moine schists, collected in traverses across the lower levels of the Moine Nappe in the Eriboll area, are presented. On approaching the Moine Thrust from the Kyle of Tongue, the following microstructural sequence is encountered: interlayered coarse grained biotite psammitic and schistose tectonites being in part mylonitic with two platy slide zones, one containing biotite and the other only muscovite and chlorite and both showing quartz microstructures indicative of post-tectonic relaxation; these pass into more mylonitic rocks nearer the thrust zone which in turn passes into the main chlorite-grade mylonite belt and finally, adjacent to the Moine Thrust, into reworked lower chlorite grade mylonites. Although there is some local variation, the overall quartz c-axis fabric is an incomplete asymmetric type I girdle. The main variation is the development of type II girdles in the reworked, ultrafine grained mylonites. The extent of the mylonitization is more extensive than previously reported. Studies of folds within the mylonite belt have revealed eye structures and small-scale folds; many are sheath folds. They cannot be unequivocally correlated with large-scale recumbent folds within the Moine Nappe. The results presented indicate that mylonitization is not limited to a single phase, and raises the possibility that there may be earlier Caledonian or possibly Precambrian structural elements present in the Eriboll region Moines prior to much of the mylonitization.

  4. Biological strategy for the fabrication of highly ordered aragonite helices: the microstructure of the cavolinioidean gastropods

    PubMed Central

    Checa, Antonio G.; Macías-Sánchez, Elena; Ramírez-Rico, Joaquín

    2016-01-01

    The Cavolinioidea are planktonic gastropods which construct their shells with the so-called aragonitic helical fibrous microstructure, consisting of a highly ordered arrangement of helically coiled interlocking continuous crystalline aragonite fibres. Our study reveals that, despite the high and continuous degree of interlocking between fibres, every fibre has a differentiated organic-rich thin external band, which is never invaded by neighbouring fibres. In this way, fibres avoid extinction. These intra-fibre organic-rich bands appear on the growth surface of the shell as minuscule elevations, which have to be secreted differentially by the outer mantle cells. We propose that, as the shell thickens during mineralization, fibre secretion proceeds by a mechanism of contact recognition and displacement of the tips along circular trajectories by the cells of the outer mantle surface. Given the sizes of the tips, this mechanism has to operate at the subcellular level. Accordingly, the fabrication of the helical microstructure is under strict biological control. This mechanism of fibre-by-fibre fabrication by the mantle cells is unlike that any other shell microstructure. PMID:27181457

  5. Fabrication and evaluation of electrohydrodynamic jet 3D printed polycaprolactone/chitosan cell carriers using human embryonic stem cell-derived fibroblasts.

    PubMed

    Wu, Yang; Sriram, Gopu; Fawzy, Amr S; Fuh, Jerry Yh; Rosa, Vinicius; Cao, Tong; Wong, Yoke San

    2016-08-01

    Biological function of adherent cells depends on the cell-cell and cell-matrix interactions in three-dimensional space. To understand the behavior of cells in 3D environment and their interactions with neighboring cells and matrix requires 3D culture systems. Here, we present a novel 3D cell carrier scaffold that provides an environment for routine 3D cell growth in vitro We have developed thin, mechanically stable electrohydrodynamic jet (E-jet) 3D printed polycaprolactone and polycaprolactone/Chitosan macroporous scaffolds with precise fiber orientation for basic 3D cell culture application. We have evaluated the application of this technology by growing human embryonic stem cell-derived fibroblasts within these 3D scaffolds. Assessment of cell viability and proliferation of cells seeded on polycaprolactone and polycaprolactone/Chitosan 3D-scaffolds show that the human embryonic stem cell-derived fibroblasts could adhere and proliferate on the scaffolds over time. Further, using confocal microscopy we demonstrate the ability to use fluorescence-labelled cells that could be microscopically monitored in real-time. Hence, these 3D printed polycaprolactone and polycaprolactone/Chitosan scaffolds could be used as a cell carrier for in vitro 3D cell culture-, bioreactor- and tissue engineering-related applications in the future. PMID:27252227

  6. Evolution and Control of 2219 Aluminum Microstructural Features Through Electron Beam Freeform Fabrication

    NASA Technical Reports Server (NTRS)

    Taminger, Karen M.; Hafley, Robert A.; Domack, Marcia S.

    2006-01-01

    The layer-additive nature of the electron beam freeform fabrication (EBF3) process results in a tortuous thermal path producing complex microstructures including: small homogeneous equiaxed grains; dendritic growth contained within larger grains; and/or pervasive dendritic formation in the interpass regions of the deposits. Several process control variables contribute to the formation of these different microstructures, including translation speed, wire feed rate, beam current and accelerating voltage. In electron beam processing, higher accelerating voltages embed the energy deeper below the surface of the substrate. Two EBF3 systems have been established at NASA Langley, one with a low-voltage (10-30kV) and the other a high-voltage (30-60 kV) electron beam gun. Aluminum alloy 2219 was processed over a range of different variables to explore the design space and correlate the resultant microstructures with the processing parameters. This report is specifically exploring the impact of accelerating voltage. Of particular interest is correlating energy to the resultant material characteristics to determine the potential of achieving microstructural control through precise management of the heat flux and cooling rates during deposition.

  7. Fabrication of axicon microlenses on capillaries and microstructured fibers by wet etching.

    PubMed

    Bachus, Kyle; Filho, Elton Soares de Lima; Wlodarczyk, Kamila; Oleschuk, Richard; Messaddeq, Younes; Loock, Hans-Peter

    2016-09-01

    A facile method is presented for the fabrication of microlenses at the facet of fused silica capillaries and microstructured fibers. After submersion in hydrogen fluoride solution water is pumped slowly through the center hole of the capillary microchannel to create an etchant gradient extending from the capillary axis. The desired axicon angle is generated by adjusting the etching time and/or concentration of the etchant. Similarly, flow- assisted HF etching of a custom microstructured fiber containing nine microchannels produces nine individual microlenses simultaneously at the fiber facet, where each microaxicon lens shows a similar focusing pattern. A theoretical model of the flow-assisted etching process is used to determine the axicon angle and post angle. Also, a simple ray-based model was applied to characterize the focusing properties of the microaxicons in good agreement with experimental observations. PMID:27607641

  8. Microstructure of the Nickel-Base Superalloy CMSX-4 Fabricated by Selective Electron Beam Melting

    NASA Astrophysics Data System (ADS)

    Ramsperger, Markus; Singer, Robert F.; Körner, Carolin

    2016-03-01

    Powder bed-based additive manufacturing (AM) processes are characterized by very high-temperature gradients and solidification rates. These conditions lead to microstructures orders of magnitude smaller than in conventional casting processes. Especially in the field of high performance alloys, like nickel-base superalloys, this opens new opportunities for homogenization and alloy development. Nevertheless, the high susceptibility to cracking of precipitation-hardenable superalloys is a challenge for AM. In this study, electron beam-based AM is used to fabricate samples from gas-atomized pre-alloyed CMSX-4 powder. The influence of the processing strategy on crack formation is investigated. The samples are characterized by optical and SEM microscopy and analyzed by microprobe analysis. Differential scanning calorimetry is used to demonstrate the effect of the fine microstructure on characteristic temperatures. In addition, in situ heat treatment effects are investigated.

  9. Microstructural characterization of Cu2ZnSn(S,Se)4 solar cells fabricated from nanoparticles

    NASA Astrophysics Data System (ADS)

    Zhang, Yiwen; Suyama, Naoki; Goto, Masanori; Kuwana, Jun; Sugimoto, Kanta; Satake, Tetsuo; Kurokawa, Yasuyoshi; Yin, Ming; Yamada, Akira

    2015-08-01

    We characterized the microstructure of Cu2ZnSn(S,Se)4 (CZTSSe) solar cells fabricated from Cu-poor, Zn-rich Cu2ZnSnSe4 (CZTSe) nanoparticles. Various sintering atmospheres of sulfur and selenium led to different microstructural properties. For the samples sintered under sulfur atmosphere, a large number of ZnS secondary phases were observed and the Zn/Sn ratio of the grains was significantly lower than 1. Regions of the ZnS secondary phases showed a dark contrast in electron-beam-induced current (EBIC) images, indicating that the existence of the ZnS phases reduced the minority carrier collection efficiency. In contrast, for the samples sintered under selenium atmosphere, Cu was found to accumulate near the grain boundaries to form the Cu-rich CZTSe phases and only a small number of ZnSe secondary phases were detected.

  10. Mechanism behind the surface evolution and microstructure changes of laser fabricated nanostructured carbon composite

    NASA Astrophysics Data System (ADS)

    Foong, Y. M.; Koh, A. T. T.; Ng, H. Y.; Chua, D. H. C.

    2011-09-01

    Many studies have shown that amorphous carbon films with reduced internal stress, improved adhesion strength, and diversified material properties are obtainable through doping process, but the presence of dopants was reported to promote surface evolution and alter the microstructures of carbon matrix. By combining analyses from experimental results and theoretical estimations, this work examines the mechanism behind the surface evolution and microstructural changes in laser fabricated nanostructured copper-carbon composite. We showed that the presence of metal ions during laser deposition increased the heat dissipation on carbon matrix, which enhanced the formation of nanoislands but graphitized the carbon matrix. In addition, theoretical estimations and XPS hinted that the presence of energetic species may force the carbon ions to react with the substrate interface and form silicon carbide bonds, which contributed to the improved adhesion strength observed in copper doped carbon films, along with a reduction in internal stress owing to the presence of nanoclusters.

  11. Programmable and self-demolding microstructured molds fabricated from shape-memory polymers

    NASA Astrophysics Data System (ADS)

    Meier, Tobias; Bur, Julia; Reinhard, Maximilian; Schneider, Marc; Kolew, Alexander; Worgull, Matthias; Hölscher, Hendrik

    2015-06-01

    We introduce shape memory polymers as materials to augment molds with programmable switching between different micro and nanostructures as functional features of the mold and self-demolding properties. These polymer molds can be used for hot embossing (or nanoimprinting) and casting. Furthermore, they enable the replication of nano- and microstructures on curved surfaces as well as embedded structures like on the inside walls of a microfluidic channel. The shape memory polymer molds can be replicated from master molds fabricated by conventional techniques. We tested their durability for microfabrication processes and demonstrated the advantages of shape memory molds for hot embossing and casting by replicating microstructures with high aspect ratios and optical grade surface quality.

  12. Microstructural Examination to Aid in Understanding Friction Bonding Fabrication Technique for Monolithic Nuclear Fuel

    SciTech Connect

    Karen L. Shropshire

    2008-04-01

    Monolithic nuclear fuel is currently being developed for use in research reactors, and friction bonding (FB) is a technique being developed to help in this fuel’s fabrication. Since both FB and monolithic fuel are new concepts, research is needed to understand the impact of varying FB fabrication parameters on fuel plate characteristics. This thesis research provides insight into the FB process and its application to the monolithic fuel design by recognizing and understanding the microstructural effects of varying fabrication parameters (a) FB tool load, and (b) FB tool face alloy. These two fabrication parameters help drive material temperature during fabrication, and thus the material properties, bond strength, and possible formation of interface reaction layers. This study analyzed temperatures and tool loads measured during those FB processes and examined microstructural characteristics of materials and bonds in samples taken from the resulting fuel plates. This study shows that higher tool load increases aluminum plasticization and forging during FB, and that the tool face alloy helps determine the tool’s heat extraction efficacy. The study concludes that successful aluminum bonds can be attained in fuel plates using a wide range of FB tool loads. The range of tool loads yielding successful uranium-aluminum bonding was not established, but it was demonstrated that such bonding can be attained with FB tool load of 48,900 N (11,000 lbf) when using a FB tool faced with a tungsten alloy. This tool successfully performed FB, and with better results than tools faced with other materials. Results of this study correlate well with results reported for similar aluminum bonding techniques. This study’s results also provide support and validation for other nuclear fuel development studies and conclusions. Recommendations are offered for further research.

  13. 3D Printing of Graphene Aerogels.

    PubMed

    Zhang, Qiangqiang; Zhang, Feng; Medarametla, Sai Pradeep; Li, Hui; Zhou, Chi; Lin, Dong

    2016-04-01

    3D printing of a graphene aerogel with true 3D overhang structures is highlighted. The aerogel is fabricated by combining drop-on-demand 3D printing and freeze casting. The water-based GO ink is ejected and freeze-cast into designed 3D structures. The lightweight (<10 mg cm(-3) ) 3D printed graphene aerogel presents superelastic and high electrical conduction. PMID:26861680

  14. Fabric and microstructural analysis of the Loch Borralan pluton, Northwest Highlands, Scotland

    NASA Astrophysics Data System (ADS)

    Calhoun, Justin

    The Loch Borralan pluton was emplaced within the Assynt Region of the Moine Thrust zone during the Scandian event (ca. 435-425 Ma) of the Caledonian Orogeny (478-425 Ma). It consists of two major magma suites, the syenitic early suite (431.1 +/- 1.2 Ma), and the quartz syenitic later suite (429.2 +/- 0.5 Ma). The region is characterized by a series of in-sequence thrust faults that strike NE-SW and dip approximately 20° to the SE, including (from lower to upper): the Sole Thrust, the Borralan Thrust (hypothesized, but not exposed), the Ben More Thrust, and the Moine Thrust. A series of imbricate thrusts between the Sole and Borralan Thrusts juxtapose repeated Cambrian and Ordovician strata. The Loch Borralan pluton intruded between the Sole and Ben More thrust faults, and may be bounded below by a hypothesized Borralan Thrust fault. Based on the overlap in pluton crystallization age and orogenic activity, the combination of macroscopic field lineation and foliation measurements, anisotropy of magnetic susceptibility (AMS) lineation and foliations measurements, mineral shape preferred orientation (SPO) analysis, and petrographic deformation microstructure analysis will be used to determine if the pluton expresses deformation features and fabrics corresponding to thrust fault tectonics. The dominant magnetic mineralogy as determined by thermomagnetic data and hysteresis plots was determined to be magnetite and titanomagnetite. Some paramagnetic components were seen in the early suite, and can be attributed to biotite. Both minerals contributed to the AMS signal that was used to interpret pluton fabrics. The pluton contains S>L (foliation stronger than lineation) fabrics throughout, defined by alignment of alkali feldspar grains. The foliation strike of both the early and late suites are subparallel to the thrust faults, providing evidence that the fabrics are related to deformation. The early suite is only well exposed in the southeast at the top of the Borralan

  15. Replication of microstructures in polymers using laser-fabricated glass-ceramic stamps

    NASA Astrophysics Data System (ADS)

    Kim, Joohan; Uppuluri, Sreemanth M.; Xu, Xianfan

    2004-07-01

    Recently much research on fabrication of polymer micro structures has been carried out. One of the main advantages of using polymer in micro structure fabrication is the easiness of applying replication processes for mass production. A micro stamping process applying heat and pressure, also referred to as hot embossing lithography, can replicate micro-structures on polymer surfaces. By reforming thermoplastics, many micro features can be transferred directly to polymer surfaces. The micro stamping consists of two main steps: a stamp fabrication step and a replication step. Until now, metal or silicon stamps have been used. In this work, photo-etchable glass-ceramic micro stamps are used, which are micro-machined using an excimer laser processing technique. With the laser process, a glass-ceramic stamp can be fabricated quickly and precisely. In addition, a micro stamping device has been designed and developed for this process. Polyvinylchloride (PVC) is used as the replicating polymer because it has a low glass transition temperature (65 C) and good formability. Many micro structures such as micro channels have been produced. The advantages and the limits of using glass-ceramics stamps and stamping with the PVC material are discussed.

  16. 3D printing of natural organic materials by photochemistry

    NASA Astrophysics Data System (ADS)

    Da Silva Gonçalves, Joyce Laura; Valandro, Silvano Rodrigo; Wu, Hsiu-Fen; Lee, Yi-Hsiung; Mettra, Bastien; Monnereau, Cyrille; Schmitt Cavalheiro, Carla Cristina; Pawlicka, Agnieszka; Focsan, Monica; Lin, Chih-Lang; Baldeck, Patrice L.

    2016-03-01

    In previous works, we have used two-photon induced photochemistry to fabricate 3D microstructures based on proteins, anti-bodies, and enzymes for different types of bio-applications. Among them, we can cite collagen lines to guide the movement of living cells, peptide modified GFP biosensing pads to detect Gram positive bacteria, anti-body pads to determine the type of red blood cells, and trypsin columns in a microfluidic channel to obtain a real time biochemical micro-reactor. In this paper, we report for the first time on two-photon 3D microfabrication of DNA material. We also present our preliminary results on using a commercial 3D printer based on a video projector to polymerize slicing layers of gelatine-objects.

  17. Fabrication of freestanding alginate microfibers and microstructures for tissue engineering applications.

    PubMed

    Szymanski, John M; Feinberg, Adam W

    2014-06-01

    Natural biopolymers such as alginate have become important materials for a variety of biotechnology applications including drug delivery, cell encapsulation and tissue engineering. This expanding use has spurred the development of new approaches to engineer these materials at the nano- and microscales to better control cell interactions. Here we describe a method to fabricate freestanding alginate-based microfibers and microstructures with tunable geometries down to approximately 3 µm. To do this, a polydimethylsiloxane stamp is used to micromold alginate or alginate-fibrin blends onto a sacrificial layer of thermally-sensitive poly(N-isopropylacrylamide) (PIPAAm). A warm calcium chloride solution is then used to crosslink the alginate and, upon cooling below the lower critical solution temperature (~32 °C), the PIPAAm layer dissolves and releases the alginate or alginate-fibrin as freestanding microfibers and microstructures. Proof-of-concept experiments demonstrate that C2C12 myoblasts seeded onto the alginate-fibrin microfibers polarize along the fiber length forming interconnected cell strands. Thus, we have developed the ability to engineer alginate-based microstructured materials that can selectively bind cells and direct cellular assembly. PMID:24695323

  18. Fabrication and biocompatibility of poly(l-lactic acid) and chitosan composite scaffolds with hierarchical microstructures.

    PubMed

    Lou, Tao; Wang, Xuejun; Yan, Xu; Miao, Yu; Long, Yun-Ze; Yin, Hai-Lei; Sun, Bin; Song, Guojun

    2016-07-01

    The scaffold microstructure is crucial to reconstruct tissue normal functions. In this article, poly(l-lactic acid) and chitosan fiber (PLLA/CTSF) composite scaffolds with hierarchical microstructures both in fiber and pore sizes were successfully fabricated by combining thermal induced phase separation and salt leaching techniques. The composite scaffolds consisted of a nanofibrous PLLA matrix with diameter of 50-500nm, and chitosan fibers with diameter of about 20μm were homogenously distributed in the PLLA matrix as a microsized reinforcer. The composite scaffolds also had high porosity (>94%) and hierarchical pore size, which were consisted of both micropores (50nm-10μm) and macropores (50-300μm). By tailoring the microstructure and chemical composition, the mechanical property, pH buffer and protein adsorption capacity of the composite scaffold were improved significantly compared with those of PLLA scaffold. Cell culture results also revealed that the PLLA/CTSF composite scaffolds supported MG-63 osteoblast proliferation and penetration. PMID:27127062

  19. Hydrophobic and oleophobic re-entrant steel microstructures fabricated using micro electrical discharge machining

    NASA Astrophysics Data System (ADS)

    Weisensee, Patricia B.; Torrealba, Eduardo J.; Raleigh, Mark; Jacobi, Anthony M.; King, William P.

    2014-09-01

    This paper presents the fabrication of metallic micro-mushroom re-entrant structures and the characterization of their hydrophobicity and oleophobicity. Five different microstructure geometries are introduced, with typical feature sizes in the range of 10-100 μm. These microstructures are realized in steel, and are fabricated over the cm-scale using micro electrical discharge machining (mEDM). The liquid repellency of these surfaces is characterized using droplets of either water (surface energy γlg = 72.4 mN m-1), RL-68H oil (γlg = 28.6 mN m-1), or Isopropanol (IPA) (γlg = 21.7 mN m-1). The water droplets form nearly perfect spheres, with contact angles in the range 146-162°, and contact angle hysteresis of 19-35°. The oil droplet contact angles are in the range 106-152° and the IPA contact angles are in the range 75-123°. Strong re-entrant features and close spacing are necessary to support a fully non-wetting state for use with oil and IPA. Water forms the highest contact angles with narrow, post-like, and widely spaced micro-mushroom geometries.

  20. The role of bedding in the evolution of meso- and microstructural fabrics in fault zones

    NASA Astrophysics Data System (ADS)

    Ishii, Eiichi

    2016-08-01

    To investigate the role of bedding in the evolution of meso- and microstructural fabrics in fault zones, detailed microscopic, mineralogical, and geochemical analyses were conducted on bedding-oblique and bedding-parallel faults that cut a folded Neogene siliceous mudstone that contains opal-CT, smectite, and illite. An analysis of asymmetric structures in the fault gouges indicates that the secondary fractures associated with each fault exhibit contrasting characteristics: those of the bedding-oblique fault are R1 shears, whereas those of the bedding-parallel fault are reactivated S foliation. The bedding-oblique fault shows the pervasive development of S foliation, lacks opal-CT, and has low SiO2/TiO2 ratios only in gouge, whereas the bedding-parallel fault exhibits these characteristics in both gouge and wall rocks. The development of S foliation and the lack of silica can result from local ductile deformation involving the sliding of phyllosilicates, coupled with pressure solution of opal-CT. Although such deformation can occur in gouge, the above results indicate that it may occur preferentially along bedding planes, preceding the formation of a gouge/slip surface. Thus, in sedimentary rocks that contain phyllosilicates and soluble minerals, bedding can influence the rheological evolution of meso- and microstructural fabrics in fault zones.

  1. 3D printing in dentistry.

    PubMed

    Dawood, A; Marti Marti, B; Sauret-Jackson, V; Darwood, A

    2015-12-01

    3D printing has been hailed as a disruptive technology which will change manufacturing. Used in aerospace, defence, art and design, 3D printing is becoming a subject of great interest in surgery. The technology has a particular resonance with dentistry, and with advances in 3D imaging and modelling technologies such as cone beam computed tomography and intraoral scanning, and with the relatively long history of the use of CAD CAM technologies in dentistry, it will become of increasing importance. Uses of 3D printing include the production of drill guides for dental implants, the production of physical models for prosthodontics, orthodontics and surgery, the manufacture of dental, craniomaxillofacial and orthopaedic implants, and the fabrication of copings and frameworks for implant and dental restorations. This paper reviews the types of 3D printing technologies available and their various applications in dentistry and in maxillofacial surgery. PMID:26657435

  2. Using low-contrast negative-tone PMMA at cryogenic temperatures for 3D electron beam lithography.

    PubMed

    Schnauber, Peter; Schmidt, Ronny; Kaganskiy, Arsenty; Heuser, Tobias; Gschrey, Manuel; Rodt, Sven; Reitzenstein, Stephan

    2016-05-13

    We report on a 3D electron beam lithography (EBL) technique using polymethyl methacrylate (PMMA) in the negative-tone regime as a resist. First, we briefly demonstrate 3D EBL at room temperature. Then we concentrate on cryogenic temperatures where PMMA exhibits a low contrast, which allows for straightforward patterning of 3D nano- and microstructures. However, conventional EBL patterning at cryogenic temperatures is found to cause severe damage to the microstructures. Through an extensive study of lithography parameters, exposure techniques, and processing steps we deduce a hypothesis for the cryogenic PMMA's structural evolution under electron beam irradiation that explains the damage. In accordance with this hypothesis, a two step lithography technique involving a wide-area pre-exposure dose slightly smaller than the onset dose is applied. It enables us to demonstrate a >95% process yield for the low-temperature fabrication of 3D microstructures. PMID:27023850

  3. Using low-contrast negative-tone PMMA at cryogenic temperatures for 3D electron beam lithography

    NASA Astrophysics Data System (ADS)

    Schnauber, Peter; Schmidt, Ronny; Kaganskiy, Arsenty; Heuser, Tobias; Gschrey, Manuel; Rodt, Sven; Reitzenstein, Stephan

    2016-05-01

    We report on a 3D electron beam lithography (EBL) technique using polymethyl methacrylate (PMMA) in the negative-tone regime as a resist. First, we briefly demonstrate 3D EBL at room temperature. Then we concentrate on cryogenic temperatures where PMMA exhibits a low contrast, which allows for straightforward patterning of 3D nano- and microstructures. However, conventional EBL patterning at cryogenic temperatures is found to cause severe damage to the microstructures. Through an extensive study of lithography parameters, exposure techniques, and processing steps we deduce a hypothesis for the cryogenic PMMA’s structural evolution under electron beam irradiation that explains the damage. In accordance with this hypothesis, a two step lithography technique involving a wide-area pre-exposure dose slightly smaller than the onset dose is applied. It enables us to demonstrate a >95% process yield for the low-temperature fabrication of 3D microstructures.

  4. Critical factors affecting the 3D microstructural formation in hybrid conductive adhesive materials studied by X-ray nano-tomography

    NASA Astrophysics Data System (ADS)

    Chen-Wiegart, Yu-Chen Karen; Figueroa-Santos, Miriam Aileen; Petrash, Stanislas; Garcia-Miralles, Jose; Wang, Jun

    2014-12-01

    Conductive adhesives are found favorable in a wide range of applications including a lead-free solder in micro-chips, flexible and printable electronics and enhancing the performance of energy storage devices. Composite materials comprised of metallic fillers and a polymer matrix are of great interest to be implemented as hybrid conductive adhesives. Here we investigated a cost-effective conductive adhesive material consisting of silver-coated copper as micro-fillers using synchrotron-based three-dimensional (3D) X-ray nano-tomography. The key factors affecting the quality and performance of the material were quantitatively studied in 3D on the nanometer scale for the first time. A critical characteristic parameter, defined as a shape-factor, was determined to yield a high-quality silver coating, leading to satisfactory performance. A `stack-and-screen' mechanism was proposed to elaborate such a phenomenon. The findings and the technique developed in this work will facilitate the future advancement of conductive adhesives to have a great impact in micro-electronics and other applications.Conductive adhesives are found favorable in a wide range of applications including a lead-free solder in micro-chips, flexible and printable electronics and enhancing the performance of energy storage devices. Composite materials comprised of metallic fillers and a polymer matrix are of great interest to be implemented as hybrid conductive adhesives. Here we investigated a cost-effective conductive adhesive material consisting of silver-coated copper as micro-fillers using synchrotron-based three-dimensional (3D) X-ray nano-tomography. The key factors affecting the quality and performance of the material were quantitatively studied in 3D on the nanometer scale for the first time. A critical characteristic parameter, defined as a shape-factor, was determined to yield a high-quality silver coating, leading to satisfactory performance. A `stack-and-screen' mechanism was proposed to

  5. 3D-printed soft microrobot for swimming in biological fluids.

    PubMed

    Qiu, Tian; Palagi, Stefano; Fischer, Peer

    2015-08-01

    Microscopic artificial swimmers hold the potential to enable novel non-invasive medical procedures. In order to ease their translation towards real biomedical applications, simpler designs as well as cheaper yet more reliable materials and fabrication processes should be adopted, provided that the functionality of the microrobots can be kept. A simple single-hinge design could already enable micro-swimming in non-Newtonian fluids, which most bodily fluids are. Here, we address the fabrication of such single-hinge microrobots with a 3D-printed soft material. Firstly, a finite element model is developed to investigate the deformability of the 3D-printed microstructure under typical values of the actuating magnetic fields. Then the microstructures are fabricated by direct 3D-printing of a soft material and their swimming performances are evaluated. The speeds achieved with the 3D-printed microrobots are comparable to those obtained in previous work with complex fabrication procedures, thus showing great promise for 3D-printed microrobots to be operated in biological fluids. PMID:26737396

  6. Fabrication of micro-structure on glass surface using micro-indentation and wet etching process

    NASA Astrophysics Data System (ADS)

    Saito, Yasuhiro; Okamoto, Shinya; Miki, Atsushi; Inomata, Hiroyuki; Hidaka, Takeshi; Kasai, Hiroaki

    2008-09-01

    In order to improve the new micro-fabrication technology using micro-indentation and wet etching, in which the etching rate drastically decrease at the indented area and consequently micro-structure can be formed on the glass surface, the effect of the applying load on the etching rate change was investigated. The extent of the etching rate change was found to be almost constant irrespective of the amount of the applying load. Therefore, the height of the structure could be controlled simply by the etching depth as far as the densified portion remains beneath the glass surface. And some example micro-patterns were fabricated in this process. Various kinds of indentation methods were employed, including scanning a pointed tool under a load and wet abrasive blast. The patterns can be freely drawn by the use of numerical control (NC) machine. Mold pattern can be also applied, which enables drawing many lines simultaneously. In every method, the heights of the patterns were confirmed to be very uniform. This new type of the micro-fabrication method was referred to as "SMIL (Stress Masked Image Lithography)".

  7. Design and fabrication of infrared antireflecting bi-periodic micro-structured surfaces

    NASA Astrophysics Data System (ADS)

    Bouffaron, R.; Escoubas, L.; Simon, J. J.; Torchio, Ph.; Flory, F.; Berginc, G.; Masclet, Ph.; Perret, C.; Schiavone, P.

    2008-04-01

    Broadband antireflection properties of material surfaces are of primary interest for a wide variety of applications: to enhance the efficiency of photovoltaic cells, to increase the sensitivity of photodetectors, to improve the performance of light emitting diodes, etc... In the past, broadband antireflection multilayer coatings were widely used and recently very low refractive index materials in thin film form have been fabricated by several groups. The research work presented in this paper aims at modeling and fabricating bi-periodic micro-structured silicon surfaces exhibiting broadband antireflection properties in the infrared range. These structures of pyramidal shape, which typical dimensions are smaller than the wavelength, are not in the Effective Medium Theory (EMT) validity domain. The optimization of the optical properties of such patterned surfaces needs a fully Finite Difference Time Domain (FDTD) rigorous description of light propagation phenomena. The influence of various opto-geometrical parameters such as period, depth, shape of the pattern is examined. The antireflective properties of such bi-periodic patterned surfaces is then discussed using the photonic crystal theory and photonic band diagrams description. The structure is considered as a two dimensional periodic structure with a nonuniform third dimension. Correlations between the density of Bloch modes, flatness of dispersion curves and the surface reflectance are presented. The last part of this paper is devoted to the presentation of the fabrication and the characterization of the structures. Low cost and large surface processing techniques are proposed using wet anisotropic etching through a silica mask obtained by photolithography or nanoimprinting.

  8. One-step fabrication of nanostructure-covered microstructures using selective aluminum anodization based on non-uniform electric field

    NASA Astrophysics Data System (ADS)

    Park, Yong Min; Kim, Byeong Hee; Seo, Young Ho

    2016-06-01

    This paper presents a selective aluminum anodization technique for the fabrication of microstructures covered by nanoscale dome structures. It is possible to fabricate bulging microstructures, utilizing the different growth rates of anodic aluminum oxide in non-uniform electric fields, because the growth rate of anodic aluminum oxide depends on the intensity of electric field, or current density. After anodizing under a non-uniform electric field, bulging microstructures covered by nanostructures were fabricated by removing the residual aluminum layer. The non-uniform electric field induced by insulative micropatterns was estimated by computational simulations and verified experimentally. Utilizing computational simulations, the intensity profile of the electric field was calculated according to the ratio of height and width of the insulative micropatterns. To compare computational simulation results and experimental results, insulative micropatterns were fabricated using SU-8 photoresist. The results verified that the shape of the bottom topology of anodic alumina was strongly dependent on the intensity profile of the applied electric field, or current density. The one-step fabrication of nanostructure-covered microstructures can be applied to various fields, such as nano-biochip and nano-optics, owing to its simplicity and cost effectiveness.

  9. Critical factors affecting the 3D microstructural formation in hybrid conductive adhesive materials studied by X-ray nano-tomography.

    PubMed

    Chen-Wiegart, Yu-chen Karen; Figueroa-Santos, Miriam Aileen; Petrash, Stanislas; Garcia-Miralles, Jose; Wang, Jun

    2015-01-21

    Conductive adhesives are found favorable in a wide range of applications including a lead-free solder in micro-chips, flexible and printable electronics and enhancing the performance of energy storage devices. Composite materials comprised of metallic fillers and a polymer matrix are of great interest to be implemented as hybrid conductive adhesives. Here we investigated a cost-effective conductive adhesive material consisting of silver-coated copper as micro-fillers using synchrotron-based three-dimensional (3D) X-ray nano-tomography. The key factors affecting the quality and performance of the material were quantitatively studied in 3D on the nanometer scale for the first time. A critical characteristic parameter, defined as a shape-factor, was determined to yield a high-quality silver coating, leading to satisfactory performance. A 'stack-and-screen' mechanism was proposed to elaborate such a phenomenon. The findings and the technique developed in this work will facilitate the future advancement of conductive adhesives to have a great impact in micro-electronics and other applications. PMID:25474162

  10. Femtosecond laser fabrication of highly hydrophobic stainless steel surface with hierarchical structures fabricated by combining ordered microstructures and LIPSS

    NASA Astrophysics Data System (ADS)

    Martínez-Calderon, M.; Rodríguez, A.; Dias-Ponte, A.; Morant-Miñana, M. C.; Gómez-Aranzadi, M.; Olaizola, S. M.

    2016-06-01

    In this work we have developed hierarchical structures that consist of micro-patterned surfaces covered by nanostructures with a femtosecond laser. The first part of this work is a study to determine the microscale modifications produced on a stainless steel alloy (AISI304) surface at high pulse energy, different velocities, and number of overscans in order to obtain microstructures with a selected depth of around 10 μm and line widths of 20 μm. The second part of the work is focused on finding the optimal irradiation parameters to obtain the nanostructure pattern. Nanostructures have been defined by means of Laser Induced Periodical Surface Structures (LIPSS) around 250 nm high and a period of 580 nm, which constitute the nanostructure pattern. Finally, dual scale gratings of 50 mm2 were fabricated with different geometries and their effect on the measured contact angle. Combining the micro-pattern with the LIPSS nano-pattern, highly hydrophobic surfaces have been developed with measured static contact angles higher than 150° on a stainless steel alloy.

  11. Development of paper-based microfluidic analytical device for iron assay using photomask printed with 3D printer for fabrication of hydrophilic and hydrophobic zones on paper by photolithography.

    PubMed

    Asano, Hitoshi; Shiraishi, Yukihide

    2015-07-01

    This paper describes a paper-based microfluidic analytical device for iron assay using a photomask printed with a 3D printer for fabrication of hydrophilic and hydrophobic zones on the paper by photolithography. Several designed photomasks for patterning paper-based microfluidic analytical devices can be printed with a 3D printer easily, rapidly and inexpensively. A chromatography paper was impregnated with the octadecyltrichlorosilane n-hexane solution and hydrophobized. After the hydrophobic zone of the paper was exposed to the UV light through the photomask, the hydrophilic zone was generated. The smallest functional hydrophilic channel and hydrophobic barrier were ca. 500 μm and ca. 100 μm in width, respectively. The fabrication method has high stability, resolution and precision for hydrophilic channel and hydrophobic barrier. This test paper was applied to the analysis of iron in water samples using a colorimetry with phenanthroline. PMID:26088776

  12. Wetting of microstructured alumina fabricated by epitaxial growth of Al4B2O9 whiskers

    NASA Astrophysics Data System (ADS)

    Wang, Yifeng; Feng, Jicai; Chen, Zhe; Song, Xiaoguo; Cao, Jian

    2015-12-01

    Topographical microstructures were fabricated on alumina by epitaxial growth of Al4B2O9 whiskers in air. The products were characterized via scanning electron microscopy, transmission electron microscopy, and X-ray diffraction. The whiskers were found to grow along the [0 0 1] crystallographic direction, and the lattice mismatch between Al2O3 and Al4B2O9 was determined to be 0.03%. The wetting of the Al4B2O9-whisker-coated surfaces by Ag-36.7Cu-8.0Ti at.% alloy was studied. The time needed to reach the equilibrium stage reduced as the temperature increased, and the final contact angle for liquid alloy on the rough surface was 27° at 880 °C. The wetting dynamics of the whiskers coated surfaces was investigated. After wetting, a whisker-interconnected region was formed between alumina and the alloy.

  13. Fabrication of a seamless roller mold with wavy microstructures using mask-less curved surface beam pen lithography

    NASA Astrophysics Data System (ADS)

    Tsai, Sung-Wen; Chen, Po-Yu; Lee, Yung-Chun

    2014-04-01

    Roller imprinting is one of the most commonly used methods for the fabrication of continuous functional structures over large areas. However, the fabrication of roller molds with seamless and complex patterns poses a significant challenge. This paper presents an innovative technique for fabricating a seamless roller mold with wavy microstructures using a novel mask-less curved surface beam pen lithography technique. The major steps in the proposed technique include spray coating a thin photo-resist (PR) layer on the roller, exposing the PR layer though a translating micro-lens array (MLA), etching the patterned PR layer, and electro-polishing the etched microstructures. The proposed method is used to pattern roller molds with different wavy microstructures by varying the rotation speed of the roller, the translation speed of the MLA holder, and the translation distance of the MLA holder. The patterned metal roller molds are then used to replicate wavy microstructures on a thin polyethylene terephthalate substrate by means of continuous UV-type roller imprinting methods. The line-width and height of the wavy microstructure are 84.5 µm and 25.5 µm, respectively.

  14. Fabrication and assessment of 3D printed anatomical models of the lower limb for anatomical teaching and femoral vessel access training in medicine.

    PubMed

    O'Reilly, Michael K; Reese, Sven; Herlihy, Therese; Geoghegan, Tony; Cantwell, Colin P; Feeney, Robin N M; Jones, James F X

    2016-01-01

    For centuries, cadaveric dissection has been the touchstone of anatomy education. It offers a medical student intimate access to his or her first patient. In contrast to idealized artisan anatomical models, it presents the natural variation of anatomy in fine detail. However, a new teaching construct has appeared recently in which artificial cadavers are manufactured through three-dimensional (3D) printing of patient specific radiological data sets. In this article, a simple powder based printer is made more versatile to manufacture hard bones, silicone muscles and perfusable blood vessels. The approach involves blending modern approaches (3D printing) with more ancient ones (casting and lost-wax techniques). These anatomically accurate models can augment the approach to anatomy teaching from dissection to synthesis of 3D-printed parts held together with embedded rare earth magnets. Vascular simulation is possible through application of pumps and artificial blood. The resulting arteries and veins can be cannulated and imaged with Doppler ultrasound. In some respects, 3D-printed anatomy is superior to older teaching methods because the parts are cheap, scalable, they can cover the entire age span, they can be both dissected and reassembled and the data files can be printed anywhere in the world and mass produced. Anatomical diversity can be collated as a digital repository and reprinted rather than waiting for the rare variant to appear in the dissection room. It is predicted that 3D printing will revolutionize anatomy when poly-material printing is perfected in the early 21st century. PMID:26109268

  15. Fabrication of rigid microstructures with thiol-ene-based soft lithography for continuous-flow cell lysis

    PubMed Central

    Burke, Jeffrey M.; Pandit, Kunal R.; Goertz, John P.

    2014-01-01

    In this work, we introduce a method for the soft-lithography-based fabrication of rigid microstructures and a new, simple bonding technique for use as a continuous-flow cell lysis device. While on-chip cell lysis techniques have been reported previously, these techniques generally require a long on-chip residence time, and thus cannot be performed in a rapid, continuous-flow manner. Microstructured microfluidic devices can perform mechanical lysis of cells, enabling continuous-flow lysis; however, rigid silicon-based devices require complex and expensive fabrication of each device, while polydimethylsiloxane (PMDS), the most common material used for soft lithography fabrication, is not rigid and expands under the pressures required, resulting in poor lysis performance. Here, we demonstrate the fabrication of microfluidic microstructures from off-stoichiometry thiol-ene (OSTE) polymer using soft-lithography replica molding combined with a post-assembly cure for easy bonding. With finite element simulations, we show that the rigid microstructures generate an energy dissipation rate of nearly 107, which is sufficient for continuous-flow cell lysis. Correspondingly, with the OSTE device we achieve lysis of highly deformable MDA-MB-231 breast cancer cells at a rate of 85%, while a comparable PDMS device leads to a lysis rate of only 40%. PMID:25538814

  16. Method to fabricate multi-level silicon-based microstructures via use of an etching delay layer

    DOEpatents

    Manginell, Ronald P.; Schubert, W. Kent; Shul, Randy J.

    2005-08-16

    New methods for fabrication of silicon microstructures have been developed. In these methods, an etching delay layer is deposited and patterned so as to provide differential control on the depth of features being etched into a substrate material. Structures having features with different depth can be formed thereby in a single etching step.

  17. Correlation between magnetic fabrics, strain and biotite microstructure with increasing mylonitisation in the pretectonic Wyangala Granite, Australia

    NASA Astrophysics Data System (ADS)

    Lennox, P. G.; de Wall, H.; Durney, D. W.

    2016-04-01

    The Wyangala Granite is a foliated, porphyritic Silurian granite from the Palaeozoic Circum-Pacific type Eastern Lachlan Orogen (ELO) of Australia. It is a paramagnetic ilmenite-bearing, S/marginal I type two-mica- to mainly biotite-granite with different biotite contents and local chlorite alteration. Very highly strained quartz-epidote bands are present. In this contribution, anisotropy of magnetic susceptibility (AMS) is compared with independently measured intensity and 3D style of strain, biotite microstructure and degree of mylonitisation for low-strain granites with weak S-foliations, through medium-strain protomylonitic granites with moderate S- and C-foliations to a high-strain altered granite with a strong single foliation. The samples are further analysed for possible contributions from sample heterogeneity, magmatic flow and 'sub-magmatic' deformation. A good correlation, P‧AMS ~ 1.02 + 0.04 ln P‧(e)Qtz, is obtained between site-average degree of AMS (P‧AMS) in the granite and degree of finite-strain anisotropy (P‧(e)Qtz) from aspect ratios of quartz aggregates in S-foliations in hand specimen and outcrop (P‧AMS 1.03-1.14, P‧(e)Qtz 1.4-19). The magnetic fabric ellipsoids agree with a kinematic regime between neutral and pure oblate predicted by the March model. The observed quartz strains, however, exceed the AMS March strains and are near neutral, plano-linear character. The geological factors that may have contributed to these differences include intra- and inter-crystalline deformation of biotite and bimodality in S and C. Magmatic fabric is not clearly evident in either the AMS or the biotite data. New data for synkinematic oligoclase, low-titanium biotite and low-sodium K-feldspar show that conditions during deformation were approximately transitional greenschist-amphibolite facies: i.e., well below solidus. This agrees with published age data that put the granite emplacement in an extensional, back-arc setting in already deformed

  18. Bioprinting of 3D hydrogels.

    PubMed

    Stanton, M M; Samitier, J; Sánchez, S

    2015-08-01

    Three-dimensional (3D) bioprinting has recently emerged as an extension of 3D material printing, by using biocompatible or cellular components to build structures in an additive, layer-by-layer methodology for encapsulation and culture of cells. These 3D systems allow for cell culture in a suspension for formation of highly organized tissue or controlled spatial orientation of cell environments. The in vitro 3D cellular environments simulate the complexity of an in vivo environment and natural extracellular matrices (ECM). This paper will focus on bioprinting utilizing hydrogels as 3D scaffolds. Hydrogels are advantageous for cell culture as they are highly permeable to cell culture media, nutrients, and waste products generated during metabolic cell processes. They have the ability to be fabricated in customized shapes with various material properties with dimensions at the micron scale. 3D hydrogels are a reliable method for biocompatible 3D printing and have applications in tissue engineering, drug screening, and organ on a chip models. PMID:26066320

  19. Modeling of Ultrasonic Testing of Woven Fabric Laminates: a Microstructure Approach

    NASA Astrophysics Data System (ADS)

    Hegemann, J.; Peiffer, A.; Van Den Broucke, B.; Baier, H.

    2009-03-01

    New complex materials constitute new challenges for the well established nondestructive ultrasonic testing (UT) methods. In aeronautic industry Carbon Fiber Reinforced Plastics (CFRP) with a high level of inner inhomogeneity are used. New construction methods of these materials lead to manufacturing problems that cannot be monitored satisfactorily yet. Therefore a consolidated knowledge of the materials and of the interactions during testing is necessary. Modeling is a promising tool to improve the understanding of physical backgrounds and thus, to reduce testing costs. In this work UT of three-dimensional models of woven fabrics on microstructure level is simulated for the first time. Therefore, model generation and simulation performance are performed separately. The inner geometry of laminates made of woven fabrics is modeled using the software module WiseTex, a textile pre-processor developed by the Catholic University of Leuven, Belgium. In these models the wave propagation is numerically calculated using the Elastodynamic Finite Integration Technique (EFIT) implemented with C++. The calculations are performed for fully orthotropic and heterogeneous media. The resolution of the investigated inner structure is in the range of micrometers depending on the frequency range. The possibility of introducing defects in the structure is shown. The influence of the interfaces between carbon fiber rovings, matrix and defects on the wave propagation is investigated. Finally comparisons of the results with experimental data are presented.

  20. Fabrication and Microstructure of Hydroxyapatite Coatings on Zirconia by Room Temperature Spray Process.

    PubMed

    Seo, Dong Seok; Chae, Hak Cheol; Lee, Jong Kook

    2015-08-01

    Hydroxyapatite coatings were fabricated on zirconia substrates by a room temperature spray process and were investigated with regards to their microstructure, composition and dissolution in water. An initial hydroxyapatite powder was prepared by heat treatment of bovine-bone derived powder at 1100 °C for 2 h, while dense zirconia substrates were fabricated by pressing 3Y-TZP powder and sintering it at 1350 °C for 2 h. Room temperature spray coating was performed using a slit nozzle in a low pressure-chamber with a controlled coating time. The phase composition of the resultant hydroxyapatite coatings was similar to that of the starting powder, however, the grain size of the hydroxyapatite particles was reduced to about 100 nm due to their formation by particle impaction and fracture. All areas of the coating had a similar morphology, consisting of reticulated structure with a high surface roughness. The hydroxyapatite coating layer exhibited biostability in a stimulated body fluid, with no severe dissolution being observed during in vitro experimentation. PMID:26369194

  1. Study of double-side ultrasonic embossing for fabrication of microstructures on thermoplastic polymer substrates.

    PubMed

    Luo, Yi; Yan, Xu; Qi, Na; Wang, Xiaodong; Wang, Liangjiang

    2013-01-01

    Double-side replication of polymer substrates is beneficial to the design and the fabrication of 3-demensional devices. The ultrasonic embossing method is a promising, high efficiency and low cost replication method for thermoplastic substrates. It is convenient to apply silicon molds in ultrasonic embossing, because microstructures can be easily fabricated on silicon wafers with etching techniques. To reduce the risk of damaging to silicon molds and to improve the replication uniformity on both sides of the polymer substrates, thermal assisted ultrasonic embossing method was proposed and tested. The processing parameters for the replication of polymethyl methacrylate (PMMA), including ultrasonic amplitude, ultrasonic force, ultrasonic time, and thermal assisted temperature were studied using orthogonal array experiments. The influences of the substrate thickness, pattern style and density were also investigated. The experiment results show that the principal parameters for the upper and lower surface replication are ultrasonic amplitude and thermal assisted temperature, respectively. As to the replication uniformity on both sides, the ultrasonic force has the maximal influence. Using the optimized parameters, the replication rate reached 97.5% on both sides of the PMMA substrate, and the cycle time was less than 50 s. PMID:23630605

  2. Study of Double-Side Ultrasonic Embossing for Fabrication of Microstructures on Thermoplastic Polymer Substrates

    PubMed Central

    Luo, Yi; Yan, Xu; Qi, Na; Wang, Xiaodong; Wang, Liangjiang

    2013-01-01

    Double-side replication of polymer substrates is beneficial to the design and the fabrication of 3-demensional devices. The ultrasonic embossing method is a promising, high efficiency and low cost replication method for thermoplastic substrates. It is convenient to apply silicon molds in ultrasonic embossing, because microstructures can be easily fabricated on silicon wafers with etching techniques. To reduce the risk of damaging to silicon molds and to improve the replication uniformity on both sides of the polymer substrates, thermal assisted ultrasonic embossing method was proposed and tested. The processing parameters for the replication of polymethyl methacrylate (PMMA), including ultrasonic amplitude, ultrasonic force, ultrasonic time, and thermal assisted temperature were studied using orthogonal array experiments. The influences of the substrate thickness, pattern style and density were also investigated. The experiment results show that the principal parameters for the upper and lower surface replication are ultrasonic amplitude and thermal assisted temperature, respectively. As to the replication uniformity on both sides, the ultrasonic force has the maximal influence. Using the optimized parameters, the replication rate reached 97.5% on both sides of the PMMA substrate, and the cycle time was less than 50 s. PMID:23630605

  3. Current transport and microstructural evolution in BSCCO tapes fabricated by groove rolling.

    SciTech Connect

    Balachandran, U.; Iyer, A. N.; Mironova, M.; Salama, K.; Stolbov, S.; Vipulanandan, C.

    1999-01-27

    The powder-in-tube technique, consisting of wire drawing and rolling, has been widely used to fabricate superconducting tapes for possible electric power applications. In this study, instead of wire drawing, the starting billet was reduced in size by groove rolling. To optimize the deformation and thermomechanical treatment process, wires of varying dimensions were fabricated. The wires were flat-rolled to a final thickness of 250 mm. Short-length tapes were subjected to a series of thermal and deformation steps. Phase development and microstructural evolution during the process were monitored by XRD, SEM, and TEM. The BSCCO-2223 tapes, which were subjected to thermomechanical treatment, had average critical current densities of 18,000 A cm{sup {minus}2}. Colony boundaries, examined by TEM, near the superconductor-silver interface were found to form in certain preferred orientations. Polytypoids of 2212 phase were also observed at the colony boundary. The effects of grain boundary on superconducting order parameter and critical current density have also been examined.

  4. Interfacial microstructure in a B{sub 4}C/Al composite fabricated by pressureless infiltration.

    SciTech Connect

    Luo, Z.; Song, Y.; Zhang, S.; Miller, D. J.

    2012-01-01

    In this work, B{sub 4}C particulate-reinforced Al composite was fabricated by a pressureless infiltration technique, and its interfacial microstructure was studied in detail by X-ray diffraction as well as by scanning and transmission electron microscopy. The B{sub 4}C phase was unstable in Al melt during the infiltration process, forming AlB{sub 10}-type AlB{sub 24}C{sub 4} or Al{sub 2.1}B{sub 51}C{sub 8} as a major reactant phase. The Al matrix was large grains (over 10 {micro}m), which had no definite orientation relationships (ORs) with the randomly orientated B{sub 4}C or its reactant particles, except for possible nucleation sites with {l_brace}011{r_brace}{sub B{sub 4}C} almost parallel to {l_brace}111{r_brace}{sub Al} at a deviation angle of 1.5 deg. Both B{sub 4}C-Al and reactant-Al interfaces are semicoherent and free of other phases. A comparison was made with the SiC/Al composite fabricated similarly by the pressureless infiltration. It was suggested that the lack of ORs between the Al matrix and reinforced particles, except for possible nucleation sites, is the common feature of the composites prepared by the infiltration method.

  5. A New Total Digital Smile Planning Technique (3D-DSP) to Fabricate CAD-CAM Mockups for Esthetic Crowns and Veneers

    PubMed Central

    Mastrangelo, F.; Gherlone, E. F.; Gastaldi, G.

    2016-01-01

    Purpose. Recently, the request of patients is changed in terms of not only esthetic but also previsualization therapy planning. The aim of this study is to evaluate a new 3D-CAD-CAM digital planning technique that uses a total digital smile process. Materials and Methods. Study participants included 28 adult dental patients, aged 19 to 53 years, with no oral, periodontal, or systemic diseases. For each patient, 3 intra- and extraoral pictures and intraoral digital impressions were taken. The digital images improved from the 2D Digital Smile System software and the scanner stereolithographic (STL) file was matched into the 3D-Digital Smile System to obtain a virtual previsualization of teeth and smile design. Then, the mockups were milled using a CAM system. Minimally invasive preparation was carried out on the enamel surface with the mockups as position guides. Results. The patients found both the digital smile design previsualization (64.3%) and the milling mockup test (85.7%) very effective. Conclusions. The new total 3D digital planning technique is a predictably and minimally invasive technique, allows easy diagnosis, and improves the communication with the patient and helps to reduce the working time and the errors usually associated with the classical prosthodontic manual step. PMID:27478442

  6. A New Total Digital Smile Planning Technique (3D-DSP) to Fabricate CAD-CAM Mockups for Esthetic Crowns and Veneers.

    PubMed

    Cattoni, F; Mastrangelo, F; Gherlone, E F; Gastaldi, G

    2016-01-01

    Purpose. Recently, the request of patients is changed in terms of not only esthetic but also previsualization therapy planning. The aim of this study is to evaluate a new 3D-CAD-CAM digital planning technique that uses a total digital smile process. Materials and Methods. Study participants included 28 adult dental patients, aged 19 to 53 years, with no oral, periodontal, or systemic diseases. For each patient, 3 intra- and extraoral pictures and intraoral digital impressions were taken. The digital images improved from the 2D Digital Smile System software and the scanner stereolithographic (STL) file was matched into the 3D-Digital Smile System to obtain a virtual previsualization of teeth and smile design. Then, the mockups were milled using a CAM system. Minimally invasive preparation was carried out on the enamel surface with the mockups as position guides. Results. The patients found both the digital smile design previsualization (64.3%) and the milling mockup test (85.7%) very effective. Conclusions. The new total 3D digital planning technique is a predictably and minimally invasive technique, allows easy diagnosis, and improves the communication with the patient and helps to reduce the working time and the errors usually associated with the classical prosthodontic manual step. PMID:27478442

  7. Optoplasmonics: hybridization in 3D

    NASA Astrophysics Data System (ADS)

    Rosa, L.; Gervinskas, G.; Žukauskas, A.; Malinauskas, M.; Brasselet, E.; Juodkazis, S.

    2013-12-01

    Femtosecond laser fabrication has been used to make hybrid refractive and di ractive micro-optical elements in photo-polymer SZ2080. For applications in micro- uidics, axicon lenses were fabricated (both single and arrays), for generation of light intensity patterns extending through the entire depth of a typically tens-of-micrometers deep channel. Further hybridisation of an axicon with a plasmonic slot is fabricated and demonstrated nu- merically. Spiralling chiral grooves were inscribed into a 100-nm-thick gold coating sputtered over polymerized micro-axicon lenses, using a focused ion beam. This demonstrates possibility of hybridisation between optical and plasmonic 3D micro-optical elements. Numerical modelling of optical performance by 3D-FDTD method is presented.

  8. Laser direct writing 3D structures for microfluidic channels: flow meter and mixer

    NASA Astrophysics Data System (ADS)

    Lin, Chih-Lang; Liu, Yi-Jui; Lin, Zheng-Da; Wu, Bo-Long; Lee, Yi-Hsiung; Shin, Chow-Shing; Baldeck, Patrice L.

    2015-03-01

    The 3D laser direct-writing technology is aimed at the modeling of arbitrary three-dimensional (3D) complex microstructures by scanning a laser-focusing point along predetermined trajectories. Through the perspective technique, the details of designed 3D structures can be properly fabricated in a microchannel. This study introduces a direct reading flow meter and a 3D passive mixer fabricated by laser direct writing for microfluidic applications. The flow meter consists of two rod-shaped springs, a pillar, an anchor, and a wedge-shaped indicator, installed inside a microfluidic channel. The indicator is deflected by the flowing fluid while restrained by the spring to establish an equilibrium indication according to the flow rate. The measurement is readily carried out by optical microscopy observation. The 3D passive Archimedes-screw-shaped mixer is designed to disturb the laminar flow 3D direction for enhancing the mixing efficiency. The simulation results indicate that the screw provides 3D disturbance of streamlines in the microchannel. The mixing demonstration for fluids flowing in the micrchannel approximately agrees with the simulation result. Thanks to the advantage of the laser direct writing technology, this study performs the ingenious applications of 3D structures for microchannels.

  9. Microstructures and mechanical properties of Co-29Cr-6Mo alloy fabricated by selective laser melting process for dental applications.

    PubMed

    Takaichi, Atsushi; Suyalatu; Nakamoto, Takayuki; Joko, Natsuka; Nomura, Naoyuki; Tsutsumi, Yusuke; Migita, Satoshi; Doi, Hisashi; Kurosu, Shingo; Chiba, Akihiko; Wakabayashi, Noriyuki; Igarashi, Yoshimasa; Hanawa, Takao

    2013-05-01

    The selective laser melting (SLM) process was applied to a Co-29Cr-6Mo alloy, and its microstructure, mechanical properties, and metal elution were investigated to determine whether the fabrication process is suitable for dental applications. The microstructure was evaluated using scanning electron microscopy with energy-dispersed X-ray spectroscopy (SEM-EDS), X-ray diffractometry (XRD), and electron back-scattered diffraction pattern analysis. The mechanical properties were evaluated using a tensile test. Dense builds were obtained when the input energy of the laser scan was higher than 400 J mm⁻³, whereas porous builds were formed when the input energy was lower than 150 J mm⁻³. The microstructure obtained was unique with fine cellular dendrites in the elongated grains parallel to the building direction. The γ phase was dominant in the build and its preferential <001> orientation was confirmed along the building direction, which was clearly observed for the builds fabricated at lower input energy. Although the mechanical anisotropy was confirmed in the SLM builds due to the unique microstructure, the yield strength, UTS, and elongation were higher than those of the as-cast alloy and satisfied the type 5 criteria in ISO22764. Metal elution from the SLM build was smaller than that of the as-cast alloy, and thus, the SLM process for the Co-29Cr-6Mo alloy is a promising candidate for fabricating dental devices. PMID:23500549

  10. Europeana and 3D

    NASA Astrophysics Data System (ADS)

    Pletinckx, D.

    2011-09-01

    The current 3D hype creates a lot of interest in 3D. People go to 3D movies, but are we ready to use 3D in our homes, in our offices, in our communication? Are we ready to deliver real 3D to a general public and use interactive 3D in a meaningful way to enjoy, learn, communicate? The CARARE project is realising this for the moment in the domain of monuments and archaeology, so that real 3D of archaeological sites and European monuments will be available to the general public by 2012. There are several aspects to this endeavour. First of all is the technical aspect of flawlessly delivering 3D content over all platforms and operating systems, without installing software. We have currently a working solution in PDF, but HTML5 will probably be the future. Secondly, there is still little knowledge on how to create 3D learning objects, 3D tourist information or 3D scholarly communication. We are still in a prototype phase when it comes to integrate 3D objects in physical or virtual museums. Nevertheless, Europeana has a tremendous potential as a multi-facetted virtual museum. Finally, 3D has a large potential to act as a hub of information, linking to related 2D imagery, texts, video, sound. We describe how to create such rich, explorable 3D objects that can be used intuitively by the generic Europeana user and what metadata is needed to support the semantic linking.

  11. In Situ Monitoring of Microstructures during Subsequent Phase Transitions in the Olivine System up to 30 GPa and 1100 K Using 3D-XRD Single-Grain Analysis. Effects of Grain Size Evolution on the Stagnation of Slab.

    NASA Astrophysics Data System (ADS)

    Rosa, A. D.; Hilairet, N.; Ghosh, S.; Jacobs, J.; Perrillat, J. P.; Vaughan, G. B. M.; Garbarino, G.; Mezouar, N.; Merkel, S.

    2014-12-01

    Microstructures significantly influence the rheological properties of rocks and are important to understand geodynamical processes such as the descent of slabs. For example, grain size reductions during phase transitions in the dominant upper mantle constituent, olivine, to its high-pressure polymorphs wadsleyite and ringwoodite have been related to the stagnation of slabs in the transition zone. Detailed studies of the microstructure development, underlying transformation mechanism and transformation kinetics are needed in order to assess the effects of these phase transformations on the rheological properties of the slab material and to build reliable models of mantle flow and slab subduction behaviors. So far, the experimental studies dedicated to this theme were mostly based on ex situ techniques (e.g. electron microscopy of quenched products).In this contribution, we present detailed results form in situ single-grain analysis on the evolution of microstructures during the succession of phase transitions in Mg2SiO4*H2O. We used a new approach based on in situ three dimensional-X-ray diffraction (3D-XRD) experiments performed up to 30 GPa and 1100 K using a resistively heated diamond anvil cell at the beam lines ID11 and ID27 of the ESRF. The individual orientations, crystallographic parameters and growth rates of numerous grains inside a polycrystalline sample have been monitored in situ at the high pressure and temperature conditions and while the material was transforming. These parameters have been used to infer grain size distributions, textural relations between parent and newly formed phase and their evolution with ongoing transformation, as well as changing PT conditions and transformation kinetics. This original dataset allows drawing a refined picture of phase transitions in the most abundant minerals of the Earth's upper mantle, shed new light on the origin of seismic anomalies at transition zone depth and provide new grounds for complex simulations

  12. Fabrication of 3D interconnected porous TiO2 nanotubes templated by poly(vinyl chloride-g-4-vinyl pyridine) for dye-sensitized solar cells

    NASA Astrophysics Data System (ADS)

    Koh, Joo Hwan; Koh, Jong Kwan; Seo, Jin Ah; Shin, Jong-Shik; Kim, Jong Hak

    2011-09-01

    Porous TiO2 nanotube arrays with three-dimensional (3D) interconnectivity were prepared using a sol-gel process assisted by poly(vinyl chloride-graft-4-vinyl pyridine), PVC-g-P4VP graft copolymer and a ZnO nanorod template. A 7 µm long ZnO nanorod array was grown from the fluorine-doped tin oxide (FTO) glass via a liquid phase deposition method. The TiO2 sol-gel solution templated by the PVC-g-P4VP graft copolymer produced a random 3D interconnection between the adjacent ZnO nanorods during spin coating. Upon etching of ZnO, TiO2 nanotubes consisting of 10-15 nm nanoparticles were generated, as confirmed by wide-angle x-ray scattering (WAXS), energy-filtering transmission electron microscopy (EF-TEM) and field-emission scanning electron microscopy (FE-SEM). The ordered and interconnected nanotube architecture showed an enhanced light scattering effect and increased penetration of polymer electrolytes in dye-sensitized solar cells (DSSC). The energy conversion efficiency reached 1.82% for liquid electrolyte, and 1.46% for low molecular weight (Mw) and 0.74% for high Mw polymer electrolytes.

  13. A novel method of hotspot temperature reduction for a 3D stacked CMOS IC chip device fabricated on an ultrathin substrate

    NASA Astrophysics Data System (ADS)

    Kato, Fumiki; Nakagawa, Hiroshi; Aoyagi, Masahiro

    2013-02-01

    A high-performance thermal management method for three-dimensional integrated circuit (IC) integration has been developed for use in conjunction with a three-dimensional (3D) large-scale integration (LSI) technology. By depositing a 10 µm thick high thermal conductivity (HTC) film consisting of 1680 alternating layers of silicon and graphite nano-films directly onto the backside of a Si substrate via an automatic sequencing sputtering method, reduction in the transient hotspot temperature in a thin-substrate CMOS IC chip is achieved. It is shown that this novel HTC film is able to overcome the thermal problems associated with thin substrates and allow the cooling of stacked ICs. In the work described in this paper, we demonstrated the performance of the HTC using a 100 µm thick substrate IC chip consisting of a complementary metal-oxide semiconductor (CMOS) ring oscillator circuit film. Our experimental results, which were confirmed in simulation, reveal a 28% reduction in the hotspot temperature rise owing to the presence of the HTC film. This technology is applicable to future developments in the 3D ultrathin substrate LSI chip stacking technology utilizing through-silicon vias (TSVs) and micro-bumps.

  14. Design, fabrication, and implementation of voxel-based 3D printed textured phantoms for task-based image quality assessment in CT

    NASA Astrophysics Data System (ADS)

    Solomon, Justin; Ba, Alexandre; Diao, Andrew; Lo, Joseph; Bier, Elianna; Bochud, François; Gehm, Michael; Samei, Ehsan

    2016-03-01

    In x-ray computed tomography (CT), task-based image quality studies are typically performed using uniform background phantoms with low-contrast signals. Such studies may have limited clinical relevancy for modern non-linear CT systems due to possible influence of background texture on image quality. The purpose of this study was to design and implement anatomically informed textured phantoms for task-based assessment of low-contrast detection. Liver volumes were segmented from 23 abdominal CT cases. The volumes were characterized in terms of texture features from gray-level co-occurrence and run-length matrices. Using a 3D clustered lumpy background (CLB) model, a fitting technique based on a genetic optimization algorithm was used to find the CLB parameters that were most reflective of the liver textures, accounting for CT system factors of spatial blurring and noise. With the modeled background texture as a guide, a cylinder phantom (165 mm in diameter and 30 mm height) was designed, containing 20 low-contrast spherical signals (6 mm in diameter at targeted contrast levels of ~3.2, 5.2, 7.2, 10, and 14 HU, 4 repeats per signal). The phantom was voxelized and input into a commercial multi-material 3D printer (Object Connex 350), with custom software for voxel-based printing. Using principles of digital half-toning and dithering, the 3D printer was programmed to distribute two base materials (VeroWhite and TangoPlus, nominal voxel size of 42x84x30 microns) to achieve the targeted spatial distribution of x-ray attenuation properties. The phantom was used for task-based image quality assessment of a clinically available iterative reconstruction algorithm (Sinogram Affirmed Iterative Reconstruction, SAFIRE) using a channelized Hotelling observer paradigm. Images of the textured phantom and a corresponding uniform phantom were acquired at six dose levels and observer model performance was estimated for each condition (5 contrasts x 6 doses x 2 reconstructions x 2

  15. Direct fabrication of electrically functional microstructures by fully voltage-controlled electrohydrodynamic jet printing of silver nano-ink

    NASA Astrophysics Data System (ADS)

    Wang, Ke; Stark, John P. W.

    2010-06-01

    We report electrohydrodynamic jet (E-jet) printing of a commercialised silver nano-ink in fully voltage-controlled fashion. Metallic pads and conducting tracks with hundred-micron feature size were drop-on-demands produced on Si substrates. Layer-by-layer printing was further performed, demonstrating a capability in creating 3D multistructures. Planar pattern with a large inductance of 2.5 μH and an excellent resistivity of 4.2×10-8 Ω m was fabricated, showing a true inductive device. Our result demonstrates a feasibility of E-jet printing in the application of smart electronic devices fabrication.

  16. Rapid fabrication of a microdevice with concave microwells and its application in embryoid body formation

    PubMed Central

    Xu, Youchun; Xie, Fengbo; Qiu, Tian; Xie, Lan; Xing, Wanli; Cheng, Jing

    2012-01-01

    Here, we report a novel method for the fabrication of polydimethylsiloxane microdevices with complicated 3-D structures, such as concave and crater shapes, using an easily machined polymethyl methacrylate mold combined with a one-step molding process. The procedure presented here enables rapid preparation of complex 3-D microstructures varying in shape and dimensions. To regulate embryoid body (EB) formation, we fabricated a microfluidic device with an array of concave microwells and found that EBs growing in microwells maintained their shape, viability, and a high degree of homogeneity. We believe that this novel method provides an alternative for rapid prototyping, especially in fabricating devices with curved 3-D microstructures. PMID:22662100

  17. Fabrication of a definitive obturator from a 3D cast with a chairside digital scanner for a patient with severe gag reflex: a clinical report.

    PubMed

    Londono, Jimmy; Abreu, Amara; Baker, Philip S; Furness, Alan R

    2015-11-01

    Patient gagging is a common problem during dental procedures such as maxillary impression making. This clinical report describes the use of a chairside intraoral scanner for a patient with a hypersensitive gag reflex. The technique proved to be a more comfortable alternative for the patient and an accurate method for the clinician to capture both hard and soft tissue detail for the fabrication of a definitive obturator. PMID:26182852

  18. Intermodal interferometer for strain and temperature sensing fabricated in birefringent boron doped microstructured fiber.

    PubMed

    Statkiewicz-Barabach, G; Carvalho, J P; Frazão, O; Olszewski, J; Mergo, P; Santos, J L; Urbanczyk, W

    2011-07-20

    We present a compact in-line fiber interferometric sensor fabricated in a boron doped two-mode highly birefringent microstructured fiber using a CO(2) laser. The intermodal interference arises at the fiber output due to coupling between the fundamental and the first order modes occurring at two fiber tapers distant by a few millimeters. The visibility of intermodal interference fringes is modulated by a polarimetric differential signal and varies in response to measurand changes. The proposed interferometer was tested for measurements of the strain and temperature, respectively, in the range of 20-700 °C and 0-17 mstrain. The sensitivity coefficients corresponding to fringe displacement and contrast variations are equal respectively for strain -2.51 nm/mstrain and -0.0256 1/mstrain and for temperature 16.7 pm/°C and 5.74×10(-5) 1/°C. This allows for simultaneous measurements of the two parameters by interrogation of the visibility and the displacement of interference fringes. PMID:21772355

  19. Microstructure, mechanical properties and in vitro bioactivity of akermanite scaffolds fabricated by laser sintering.

    PubMed

    Han, Zikai; Feng, Pei; Gao, Chengde; Shen, Yang; Shuai, Cijun; Peng, Shuping

    2014-01-01

    Akermanite had attracted great attention due to the favourable mechanical properties and excellent biological performance. In this research, the microstructure and mechanical properties of akermanite scaffolds fabricated via laser sintering under different process conditions were studied and characterized. The results showed that the akermanite particles gradually mixed together, grew up and reached complete densification with the scanning speed decreasing from 450 to 150 mm/min, while micro defects such as air holes occurred at 50mm/min. simultaneously, the compressive strength of the scaffolds went up and then descended, and the optimum value was 5.92 ± 0.41 MPa. The Vickers hardness and fracture toughness increased consistently and then tended to stabilize. X-ray diffraction (XRD) results indicated no new phase appeared under all process conditions. MG-63 cell culture revealed that cell adhesion and proliferation occurred, indicating excellent cytocompatibility of the scaffolds. Moreover, in vitro bioactivity tests showed that the apatite layer formed on the scaffolds and became dense and thick with the increase of soaking time in simulated body fluid (SBF), and this fact was further confirmed by energy-dispersive spectroscopy (EDS). PMID:25226904

  20. Microstructure, microhardness and wear resistance of VCp/Fe surface composites fabricated in situ

    NASA Astrophysics Data System (ADS)

    Ye, Fangxia; Hojamberdiev, Mirabbos; Xu, Yunhua; Zhong, Lisheng; Zhao, Nana; Li, Yaping; Huang, Xing

    2013-09-01

    The vanadium carbide particles (VCp)/Fe surface composites were in situ fabricated by a technique combining infiltration casting with subsequent heat treatment. The effects of different heat treatment times on the phase evolution, microstructure, microhardness and wear resistance of the composite were studied by means of X-ray diffraction (XRD), scanning electron microscopy (SEM), Vickers hardness tester and wear resistance testing instrument, respectively. The results show that only graphite, α-Fe and V8C7 phases dominate in the composite after being heat treated at 1164 °C for 3 h. The amount of V8C7 decreases gradually from the top surface of the composite to the matrix mainly composed of gray cast iron. The average microhardness of the VCp/Fe surface composites varies according to the different reaction zones as follows: 505 HV0.1 (vanadium plate), 1096 HV0.1 (composite region), and 235 HV0.1 (iron matrix). The microhardness of the composite region is four times higher than that of the iron matrix and two times higher than that of the vanadium plate. This is attributed to the formation of vanadium carbide (V2C and V8C7) crystallites as reinforcement phases within the iron matrix. The VCp/Fe surface composites exhibit a good wear resistance under two-body abrasive wear test.

  1. Deformation of a laser beam in the fabrication of graphite microstructures inside a volume of diamond

    NASA Astrophysics Data System (ADS)

    Kononenko, T. V.; Zavedeev, E. V.

    2016-03-01

    We report a theoretical and experimental study of the energy profile deformation along the laser beam axis during the fabrication of graphite microstructures inside a diamond crystal. The numerical simulation shows that the use of a focusing lens with a numerical aperture NA < 0.1 at a focusing depth of up to 2 mm makes it possible to avoid a noticeable change in the energy profile of the beam due to the spherical aberration that occurs in the case of refraction of the focused laser beam at the air – diamond interface. The calculation results are confirmed by experimental data on the distribution of the laser intensity along the beam axis in front of its focal plane, derived from observations of graphitisation wave propagation in diamond. The effect of radiation self-focusing on laser-induced graphitisation of diamond is analysed. It is shown that if the wavefront distortion due to self-focusing can be neglected at a minimum pulse energy required for the optical breakdown of diamond, then an increase in the beam distortion with increasing pulse energy has no effect on the graphitisation process.

  2. 3D-Printed Microfluidics.

    PubMed

    Au, Anthony K; Huynh, Wilson; Horowitz, Lisa F; Folch, Albert

    2016-03-14

    The advent of soft lithography allowed for an unprecedented expansion in the field of microfluidics. However, the vast majority of PDMS microfluidic devices are still made with extensive manual labor, are tethered to bulky control systems, and have cumbersome user interfaces, which all render commercialization difficult. On the other hand, 3D printing has begun to embrace the range of sizes and materials that appeal to the developers of microfluidic devices. Prior to fabrication, a design is digitally built as a detailed 3D CAD file. The design can be assembled in modules by remotely collaborating teams, and its mechanical and fluidic behavior can be simulated using finite-element modeling. As structures are created by adding materials without the need for etching or dissolution, processing is environmentally friendly and economically efficient. We predict that in the next few years, 3D printing will replace most PDMS and plastic molding techniques in academia. PMID:26854878

  3. Comparison of Microstructures and Mechanical Properties for Solid and Mesh Cobalt-Base Alloy Prototypes Fabricated by Electron Beam Melting

    NASA Astrophysics Data System (ADS)

    Gaytan, S. M.; Murr, L. E.; Martinez, E.; Martinez, J. L.; Machado, B. I.; Ramirez, D. A.; Medina, F.; Collins, S.; Wicker, R. B.

    2010-12-01

    The microstructures and mechanical behavior of simple, as-fabricated, solid geometries (with a density of 8.4 g/cm3), as-fabricated and fabricated and annealed femoral (knee) prototypes, and reticulated mesh components (with a density of 1.5 g/cm3) all produced by additive manufacturing (AM) using electron beam melting (EBM) of Co-26Cr-6Mo-0.2C powder are examined and compared in this study. Microstructures and microstructural issues are examined by optical metallography (OM), scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy-dispersive X-ray spectrometry (EDS), and X-ray diffraction (XRD), while mechanical properties included selective specimen tensile testing and Vickers microindentation hardness (HV) and Rockwell C-scale hardness (HRC) measurements. Orthogonal (X-Y) melt scanning of the electron beam during AM produced unique, orthogonal and related Cr23C6 carbide (precipitate) arrays (a controlled microstructural architecture) with dimensions of 2 μm in the build plane perpendicular to the build direction, while connected carbide columns were formed in the vertical plane, parallel to the build direction, with microindentation hardnesses ranging from 4.4 to 5.9 GPa, corresponding to a yield stress and ultimate tensile strength (UTS) of 0.51 and 1.45 GPa with elongations ranging from 1.9 to 5.3 pct. Annealing produced an equiaxed fcc grain structure with some grain boundary carbides, frequent annealing twins, and often a high density of intrinsic {111} stacking faults within the grains. The reticulated mesh strut microstructure consisted of dense carbide arrays producing an average microindentation hardness of 6.2 GPa or roughly 25 pct higher than the fully dense components.

  4. Differences in microstructure and properties between selective laser melting and traditional manufacturing for fabrication of metal parts: A review

    NASA Astrophysics Data System (ADS)

    Song, Bo; Zhao, Xiao; Li, Shuai; Han, Changjun; Wei, Qingsong; Wen, Shifeng; Liu, Jie; Shi, Yusheng

    2015-06-01

    Selective laser melting (SLM), as one of the additive manufacturing technologies, is widely investigated to fabricate metal parts. In SLM, parts are manufactured directly from powders in a layer-by-layer fashion; SLM also provides several advantages, such as production of complex parts with high three-dimensional accuracy, compared with other additive manufacturing technologies. Therefore, SLM can be applied in aeronautics, astronautics, medicine, and die and mould industry. However, this technique differs from traditional methods, such as casting and forging; for instance, the former greatly differs in terms of microstructure and properties of products. This paper summarizes relevant studies on metal material fabrication through SLM. Based on a work completed in Huazhong Univ. Sci Tech., Rapid Manuf. Center (HUST-RMC) and compared with characteristics described in other reported studies, microstructure, properties, dimensional accuracy, and application of SLM are presented.

  5. Printing of metallic 3D micro-objects by laser induced forward transfer.

    PubMed

    Zenou, Michael; Kotler, Zvi

    2016-01-25

    Digital printing of 3D metal micro-structures by laser induced forward transfer under ambient conditions is reviewed. Recent progress has allowed drop on demand transfer of molten, femto-liter, metal droplets with a high jetting directionality. Such small volume droplets solidify instantly, on a nanosecond time scale, as they touch the substrate. This fast solidification limits their lateral spreading and allows the fabrication of high aspect ratio and complex 3D metal structures. Several examples of micron-scale resolution metal objects printed using this method are presented and discussed. PMID:26832524

  6. Fabrication of self-organized conical microstructures by excimer laser irradiation of cyanoacrylate-carbon nanotube composites

    NASA Astrophysics Data System (ADS)

    Liu, Yuming; Liu, Liang; Fan, Shoushan

    2005-02-01

    Self-organized conical microstructures are fabricated by 308 nm XeCl excimer laser irradiation of cyanoacrylate-carbon nanotube composites in air. The morphology of the surface on the composite films is studied, varying the total number and fluence of the applied laser pulses. A simple mechanism of the fabrication based on the evaporation of cyanoacrylate and the burning of carbon nanotubes is proposed. The conical peak structures of cyanoacrylate-carbon nanotube composite films show good field-emission properties. Similar structures are also observed on carbon nanotube arrays.

  7. A surface data generation method of optical micro-structure and analysis system for Fast Tool Servo fabricating

    NASA Astrophysics Data System (ADS)

    Yang, Fan; Dai, Yi-fan; Wan, Fei; Wang, Gui-lin

    2010-10-01

    High-precision optical micro-structured components are now widely used in the field of military and civilian use. Ultraprecision machining with a fast tool servo (FTS) is one of the leading methodologies for fabrication of such surfaces. The first important issue that faced in ultra-precision and high-effectively fabricating is how to properly describe the complex shapes based on the principle of FTS. In order to meet the demands of FTS machining that need for tool high-frequency response, high data throughput and huge memory space, an off-line discrete data points generation method for microstructure surfaces is presented which can avoid on-line shape calculation in fabricating process. A new analysis software package is developed to compute the speed, acceleration and spectrum over the generated data points which helps to analysis the tool tracking characteristics needed in fabricating. Also a new mechanism for FTS machining data transmission based on the huge-capacity storage device is proposed. Experiments show that the off-line surface data generation method and data transfer mechanism can effectively improve FTS fabricating efficiency, the surface analysis software can help to determine the machining ability of tool-holder and to guide and optimize the processing parameters such as spindle speed, feed rate, etc.

  8. Anisotropic multi-step etching for large-area fabrication of surface microstructures on stainless steel to control thermal radiation

    NASA Astrophysics Data System (ADS)

    Shimizu, M.; Yamada, T.; Sasaki, K.; Takada, A.; Nomura, H.; Iguchi, F.; Yugami, H.

    2015-04-01

    Controlling the thermal radiation spectra of materials is one of the promising ways to advance energy system efficiency. It is well known that the thermal radiation spectrum can be controlled through the introduction of periodic surface microstructures. Herein, a method for the large-area fabrication of periodic microstructures based on multi-step wet etching is described. The method consists of three main steps, i.e., resist mask fabrication via photolithography, electrochemical wet etching, and side wall protection. Using this method, high-aspect micro-holes (0.82 aspect ratio) arrayed with hexagonal symmetry were fabricated on a stainless steel substrate. The conventional wet etching process method typically provides an aspect ratio of 0.3. The optical absorption peak attributed to the fabricated micro-hole array appeared at 0.8 μm, and the peak absorbance exceeded 0.8 for the micro-holes with a 0.82 aspect ratio. While argon plasma etching in a vacuum chamber was used in the present study for the formation of the protective layer, atmospheric plasma etching should be possible and will expand the applicability of this new method for the large-area fabrication of high-aspect materials.

  9. 3d-3d correspondence revisited

    NASA Astrophysics Data System (ADS)

    Chung, Hee-Joong; Dimofte, Tudor; Gukov, Sergei; Sułkowski, Piotr

    2016-04-01

    In fivebrane compactifications on 3-manifolds, we point out the importance of all flat connections in the proper definition of the effective 3d {N}=2 theory. The Lagrangians of some theories with the desired properties can be constructed with the help of homological knot invariants that categorify colored Jones polynomials. Higgsing the full 3d theories constructed this way recovers theories found previously by Dimofte-Gaiotto-Gukov. We also consider the cutting and gluing of 3-manifolds along smooth boundaries and the role played by all flat connections in this operation.

  10. 3D Printing for Tissue Engineering

    PubMed Central

    Jia, Jia; Yao, Hai; Mei, Ying

    2016-01-01

    Tissue engineering aims to fabricate functional tissue for applications in regenerative medicine and drug testing. More recently, 3D printing has shown great promise in tissue fabrication with a structural control from micro- to macro-scale by using a layer-by-layer approach. Whether through scaffold-based or scaffold-free approaches, the standard for 3D printed tissue engineering constructs is to provide a biomimetic structural environment that facilitates tissue formation and promotes host tissue integration (e.g., cellular infiltration, vascularization, and active remodeling). This review will cover several approaches that have advanced the field of 3D printing through novel fabrication methods of tissue engineering constructs. It will also discuss the applications of synthetic and natural materials for 3D printing facilitated tissue fabrication. PMID:26869728

  11. A 60-GHz-band 2 x 4 planar dipole array antenna module fabricated by 3-D SiP technology

    NASA Astrophysics Data System (ADS)

    Suematsu, Noriharu; Suzuki, Yuya; Yoshida, Satoshi; Tanifuji, Shoichi; Kameda, Suguru; Takagi, Tadashi; Tsubouchi, Kazuo

    2014-08-01

    A 2 × 4 phased array antenna module has been developed for 60-GHz-band short- range high-speed wireless communication terminals. To realize the required vertical distance between the antenna elements, the module is made of five sheets of multi-layered organic substrates vertically stacked with Cu balls, and the 1 x 4 dipole array antenna is placed on both the top and bottom organic substrates. To reduce the mutual coupling between the element antennas, a monolithic microwave integrated circuit (MMIC) is flip-chip mounted on the feed line of each element antenna. The Au-stud bump flip-chip mounting technique helps achieve a lower return loss in the transition section at the MMIC than the Au-wire bonded. The placement accuracy of each antenna element in the vertical direction, 60-GHz signal vertical interconnection between the substrates with Cu balls, and flip-chip mounting of the MMIC are confirmed by 3-D computed tomography (CT) scans.

  12. A Controlled Design of Aligned and Random Nanofibers for 3D Bi-functionalized Nerve Conduits Fabricated via a Novel Electrospinning Set-up.

    PubMed

    Kim, Jeong In; Hwang, Tae In; Aguilar, Ludwig Erik; Park, Chan Hee; Kim, Cheol Sang

    2016-01-01

    Scaffolds made of aligned nanofibers are favorable for nerve regeneration due to their superior nerve cell attachment and proliferation. However, it is challenging not only to produce a neat mat or a conduit form with aligned nanofibers but also to use these for surgical applications as a nerve guide conduit due to their insufficient mechanical strength. Furthermore, no studies have been reported on the fabrication of aligned nanofibers and randomly-oriented nanofibers on the same mat. In this study, we have successfully produced a mat with both aligned and randomly-oriented nanofibers by using a novel electrospinning set up. A new conduit with a highly-aligned electrospun mat is produced with this modified electrospinning method, and this proposed conduit with favorable features, such as selective permeability, hydrophilicity and nerve growth directional steering, were fabricated as nerve guide conduits (NGCs). The inner surface of the nerve conduit is covered with highly aligned electrospun nanofibers and is able to enhance the proliferation of neural cells. The central part of the tube is double-coated with randomly-oriented nanofibers over the aligned nanofibers, strengthening the weak mechanical strength of the aligned nanofibers. PMID:27021221

  13. A Controlled Design of Aligned and Random Nanofibers for 3D Bi-functionalized Nerve Conduits Fabricated via a Novel Electrospinning Set-up

    PubMed Central

    Kim, Jeong In; Hwang, Tae In; Aguilar, Ludwig Erik; Park, Chan Hee; Kim, Cheol Sang

    2016-01-01

    Scaffolds made of aligned nanofibers are favorable for nerve regeneration due to their superior nerve cell attachment and proliferation. However, it is challenging not only to produce a neat mat or a conduit form with aligned nanofibers but also to use these for surgical applications as a nerve guide conduit due to their insufficient mechanical strength. Furthermore, no studies have been reported on the fabrication of aligned nanofibers and randomly-oriented nanofibers on the same mat. In this study, we have successfully produced a mat with both aligned and randomly-oriented nanofibers by using a novel electrospinning set up. A new conduit with a highly-aligned electrospun mat is produced with this modified electrospinning method, and this proposed conduit with favorable features, such as selective permeability, hydrophilicity and nerve growth directional steering, were fabricated as nerve guide conduits (NGCs). The inner surface of the nerve conduit is covered with highly aligned electrospun nanofibers and is able to enhance the proliferation of neural cells. The central part of the tube is double-coated with randomly-oriented nanofibers over the aligned nanofibers, strengthening the weak mechanical strength of the aligned nanofibers. PMID:27021221

  14. SU-C-213-07: Fabrication and Testing of a 3D-Printed Small Animal Rectal Cooling Device to Evaluate Local Hypothermia as a Radioprotector During Prostate SBRT

    SciTech Connect

    Hrycushko, B; Chopra, R; Futch, C; Bing, C; Wodzak, M; Stojadinovic, S; Jiang, S; Medin, P

    2015-06-15

    Purpose: The protective effects of induced or even accidental hypothermia on the human body are widespread with several medical uses currently under active research. In vitro experiments using human cell lines have shown hypothermia provides a radioprotective effect that becomes more pronounced at large, single-fraction doses common to SBRT treatments. Relevant to prostate SBRT, this work details the fabrication and testing of a 3D-printed cooling device to facilitate the investigation of the radioprotective effect of local hypothermia on the rat rectum. Methods: A 3cm long, two-channel rectal cooling device was designed in SOLIDWORKS CAD for 3D printing. The water intake nozzle is connected to a 1mm diameter brass pipe from which water flows and circulates back around to the exit nozzle. Both nozzles are connected by plastic tubing to a water chiller pump. Following leak-proof testing, fiber optic temperature probes were used to evaluate the temperature over time when placed adjacent to the cooling device within a rat rectum. MRI thermometry characterized the relative temperature distribution in concentric ROIs surrounding the probe. CBCT images from a small-animal irradiator were evaluated for imaging artifacts which could affect Monte Carlo dose calculations during treatment planning. Results: The rectal temperature adjacent to the cooling device decreased from body temperature (37°C) to 15°C in 10–20 minutes from device insertion. Rectal temperature was maintained at 15±3°C during active cooling. MRI thermometry tests revealed a steep temperature gradient with increasing distance from the cooling device, with the desired temperature range maintained within the surrounding few millimeters. Conclusion: A 3D printed rectal cooling device was fabricated for the purpose of inducing local hypothermia in rat rectums. Rectal cooling capabilities were characterized in-vivo to facilitate an investigation of the radioprotective effect of hypothermia for late rectal

  15. 3D and Education

    NASA Astrophysics Data System (ADS)

    Meulien Ohlmann, Odile

    2013-02-01

    Today the industry offers a chain of 3D products. Learning to "read" and to "create in 3D" becomes an issue of education of primary importance. 25 years professional experience in France, the United States and Germany, Odile Meulien set up a personal method of initiation to 3D creation that entails the spatial/temporal experience of the holographic visual. She will present some different tools and techniques used for this learning, their advantages and disadvantages, programs and issues of educational policies, constraints and expectations related to the development of new techniques for 3D imaging. Although the creation of display holograms is very much reduced compared to the creation of the 90ies, the holographic concept is spreading in all scientific, social, and artistic activities of our present time. She will also raise many questions: What means 3D? Is it communication? Is it perception? How the seeing and none seeing is interferes? What else has to be taken in consideration to communicate in 3D? How to handle the non visible relations of moving objects with subjects? Does this transform our model of exchange with others? What kind of interaction this has with our everyday life? Then come more practical questions: How to learn creating 3D visualization, to learn 3D grammar, 3D language, 3D thinking? What for? At what level? In which matter? for whom?

  16. Design and Fabrication of 3D printed Scaffolds with a Mechanical Strength Comparable to Cortical Bone to Repair Large Bone Defects.

    PubMed

    Roohani-Esfahani, Seyed-Iman; Newman, Peter; Zreiqat, Hala

    2016-01-01

    A challenge in regenerating large bone defects under load is to create scaffolds with large and interconnected pores while providing a compressive strength comparable to cortical bone (100-150 MPa). Here we design a novel hexagonal architecture for a glass-ceramic scaffold to fabricate an anisotropic, highly porous three dimensional scaffolds with a compressive strength of 110 MPa. Scaffolds with hexagonal design demonstrated a high fatigue resistance (1,000,000 cycles at 1-10 MPa compressive cyclic load), failure reliability and flexural strength (30 MPa) compared with those for conventional architecture. The obtained strength is 150 times greater than values reported for polymeric and composite scaffolds and 5 times greater than reported values for ceramic and glass scaffolds at similar porosity. These scaffolds open avenues for treatment of load bearing bone defects in orthopaedic, dental and maxillofacial applications. PMID:26782020

  17. Design and fabrication of a 3D-structured gold film with nanopores for local electric field enhancement in the pore

    NASA Astrophysics Data System (ADS)

    Grant-Jacob, James A.; Zin Oo, Swe; Carpignano, Francesca; Boden, Stuart A.; Brocklesby, William S.; Charlton, Martin D. B.; Melvin, Tracy

    2016-02-01

    Three-dimensionally structured gold membrane films with nanopores of defined, periodic geometries are designed and fabricated to provide the spatially localised enhancement of electric fields by manipulation of the plasmons inside nanopores. Square nanopores of different size and orientation relative to the pyramid are considered for films in aqueous and air environments, which allow for control of the position of electric fields within the structure. Designs suitable for use with 780 nm light were created. Here, periodic pyramidal cavities produced by potassium hydroxide etching to the {111} planes of (100) silicon substrates are used as templates for creating a periodic, pyramidal structured, free-standing thin gold film. Consistent with the findings from the theoretical studies, a nano-sized hole of 50 nm square was milled through the gold film at a specific location in the cavity to provide electric field control which can subsequently used for enhancement of fluorescence or Raman scattering of molecules in the nanopore.

  18. Design and Fabrication of 3D printed Scaffolds with a Mechanical Strength Comparable to Cortical Bone to Repair Large Bone Defects

    NASA Astrophysics Data System (ADS)

    Roohani-Esfahani, Seyed-Iman; Newman, Peter; Zreiqat, Hala

    2016-01-01

    A challenge in regenerating large bone defects under load is to create scaffolds with large and interconnected pores while providing a compressive strength comparable to cortical bone (100-150 MPa). Here we design a novel hexagonal architecture for a glass-ceramic scaffold to fabricate an anisotropic, highly porous three dimensional scaffolds with a compressive strength of 110 MPa. Scaffolds with hexagonal design demonstrated a high fatigue resistance (1,000,000 cycles at 1-10 MPa compressive cyclic load), failure reliability and flexural strength (30 MPa) compared with those for conventional architecture. The obtained strength is 150 times greater than values reported for polymeric and composite scaffolds and 5 times greater than reported values for ceramic and glass scaffolds at similar porosity. These scaffolds open avenues for treatment of load bearing bone defects in orthopaedic, dental and maxillofacial applications.

  19. Design and Fabrication of 3D printed Scaffolds with a Mechanical Strength Comparable to Cortical Bone to Repair Large Bone Defects

    PubMed Central

    Roohani-Esfahani, Seyed-Iman; Newman, Peter; Zreiqat, Hala

    2016-01-01

    A challenge in regenerating large bone defects under load is to create scaffolds with large and interconnected pores while providing a compressive strength comparable to cortical bone (100–150 MPa). Here we design a novel hexagonal architecture for a glass-ceramic scaffold to fabricate an anisotropic, highly porous three dimensional scaffolds with a compressive strength of 110 MPa. Scaffolds with hexagonal design demonstrated a high fatigue resistance (1,000,000 cycles at 1–10 MPa compressive cyclic load), failure reliability and flexural strength (30 MPa) compared with those for conventional architecture. The obtained strength is 150 times greater than values reported for polymeric and composite scaffolds and 5 times greater than reported values for ceramic and glass scaffolds at similar porosity. These scaffolds open avenues for treatment of load bearing bone defects in orthopaedic, dental and maxillofacial applications. PMID:26782020

  20. Residual stresses and microstructure of H13 steel formed by combining two different direct fabrication methods

    SciTech Connect

    Maziasz, P.J.; Payzant, E.A.; Schlienger, M.E.; McHugh, K.M.

    1998-10-13

    Direct fabrication (DF) of tool and die steels by rapid solidification techniques can produce near-net-shape parts and components with unique properties, and without the distortions caused by conventional normalizing and tempering heat-treatments. When combined with sophisticated 3-dimensional computer control to build complex solid metallic shapes, one has the capability of using DF for rapid prototyping. Spray forming using a circular converging/diverging atomizer is a DF process being developed at the Idaho National Engineering and Environmental Laboratory (INEEL) for rapid manufacturing of tool and die steels like H-13. Laser Engineered Net Shaping (LENS{trademark}) is a DF process being developed at Sandia National laboratory (SNL). LENS involves laser-processing fine powder metal sprays into complex, fully-dense 3-dimensional shapes with fine-detail control that would allow rapid prototyping of tools or dies. One logical combination of the two processes is to combine spray forming to replicate most of the die surface and backing, and then t o build other die-surface fine-features with LENS. Premium H-13 steel was used because it belongs to the widely used group of hot-work steels that have good resistance to heat, pressure and abrasion for metal-forging and aluminum die-casting applications. The microstructure and residual stresses that exist across the interface of a composite metal produced by these two DF methods are critical parameters in producing crack-free components with functional properties. The purpose of this work is to combine unique neutron-diffraction facilities at the Oak Ridge National Laboratory (ORNL) for measuring bulk residual stresses with these two different DF processes to characterize LENS deposits of H-13 steel made on a spray-formed base of that same steel.

  1. Fabrication and microstructural characterization of Al/Zn-enriched layers on pure magnesium

    SciTech Connect

    Mola, Renata

    2013-04-15

    Al/Zn-enriched surface layers were fabricated by heating Mg specimens in contact with Al–Zn powder mixtures in a vacuum furnace at 445 °C. The layer formation process took place through partial melting at the Mg-substrate/powder-mixture interface. Heating times ranged from 20 to 80 min. The layer microstructure and composition were analyzed by optical microscopy (OM), scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS). The layers were 100–900 μm in thickness, depending on the treatment time. The examination results revealed that the layers consisted of Mg{sub 17}(Al,Zn){sub 12} and Mg{sub 5}Al{sub 2}Zn{sub 2} intermetallic phases and a solid solution of Al and Zn in Mg. Between the Al/Zn-enriched layer and the Mg substrate, there was a transition zone of a solid solution of Al and Zn in Mg with a thickness of 20–30 μm. The layers had much higher microhardness than the Mg substrate. - Highlights: ► The layers were produced by heating Mg in contact with an Al–Zn powder mixture. ► The layer formation process at 445 °C proceeded with the liquid phase contribution. ► The Al/Zn-enriched layers were thick, dense, uniform and continuous. ► The layers contained Mg–Al–Zn intermetallic phases. ► The hardness of the layers was much higher than that of the Mg substrate.

  2. Combined magnetic fabrics and microstructures: evidence of an early magmatic event in the Paleoproterozoic Teofilandia granitoids (Sao Francisco craton, Brazil)

    NASA Astrophysics Data System (ADS)

    Nascimento, H. S.; Bouchez, J. L.; Nedelec, A.; Sabate, P.

    2003-04-01

    The study area concerns the southern part of the Paleoproterozoic (2.2--2.0 Ga) Itapicuru Greenstone Belt (Serrinha Block), eastern border of the Sao Francisco craton (Brazil). This is a problematic area, occupied by the Teofilandia granitoids (granites, granodiorites, tonalites, gneisses), where the overall N-S map structures rotate to E-W toward the south of the Serrinha Block. A set of 160 sampling stations covering ˜220 km^2 have been subjected to a detailed structural study combining magnetic fabrics AND microstructural characters. Three types of microstructures, corresponding to three successive events, helped to sort the different magnetic fabrics. (1) Purely magmatic microstructures, sometimes slightly overprinted by the following events, characterize preserved sectors that carry N-S trending magnetic lineations. Around these relictual sectors (2) the granitoids display typical high-T orthogneissic microstructures, attesting for their pervasive deformation in the solid-state parallel to E-W (±30^o), as observed in the field and attested by the E-W trending magnetic lineations. Finally (3) low-T/high-stress, sub-mylonitic microstructures under greenschist facies conditions, affect the area with various intensities, and are associated with E-W trending magnetic lineations. We conclude that the Teofilandia granitoids reveal their N-S-directed emplacement at ˜2.1 Ga, probably coeval with the N-S stretch of the whole Rio Itapicuru belt, within the relictual cores of kilometer-thick lenses that were preserved from the following events. The pervasive high-T structures, with foliations dipping to the south and E-W stretching directions, are ascribed to a lateral ramp of the shear event that accompanied the convergence of the Serrinha block with the Salvador Curaca mobile belt. The final, low-T/high stress event is likely coeval with the hydrothermal episode responsible for the gold mineralizations of the Teofilandia area at 2.08 Ga.

  3. Pattern Transformation of Heat-Shrinkable Polymer by Three-Dimensional (3D) Printing Technique

    PubMed Central

    Zhang, Quan; Yan, Dong; Zhang, Kai; Hu, Gengkai

    2015-01-01

    A significant challenge in conventional heat-shrinkable polymers is to produce controllable microstructures. Here we report that the polymer material fabricated by three-dimensional (3D) printing technique has a heat-shrinkable property, whose initial microstructure can undergo a spontaneous pattern transformation under heating. The underlying mechanism is revealed by evaluating internal strain of the printed polymer from its fabricating process. It is shown that a uniform internal strain is stored in the polymer during the printing process and can be released when heated above its glass transition temperature. Furthermore, the internal strain can be used to trigger the pattern transformation of the heat-shrinkable polymer in a controllable way. Our work provides insightful ideas to understand a novel mechanism on the heat-shrinkable effect of printed material, but also to present a simple approach to fabricate heat-shrinkable polymer with a controllable thermo-structural response. PMID:25757881

  4. 3D Imaging.

    ERIC Educational Resources Information Center

    Hastings, S. K.

    2002-01-01

    Discusses 3 D imaging as it relates to digital representations in virtual library collections. Highlights include X-ray computed tomography (X-ray CT); the National Science Foundation (NSF) Digital Library Initiatives; output peripherals; image retrieval systems, including metadata; and applications of 3 D imaging for libraries and museums. (LRW)

  5. Laser microstructured biodegradable scaffolds.

    PubMed

    Koroleva, Anastasia; Kufelt, Olga; Schlie-Wolter, Sabrina; Hinze, Ulf; Chichkov, Boris

    2013-10-01

    The two-photon polymerization technique (2PP) uses non-linear absorption of femtosecond laser pulses to selectively polymerize photosensitive materials. 2PP has the ability to fabricate structures with a resolution from tens of micrometers down to hundreds of nanometers. Three-dimensional microstructuring by the 2PP technique provides many interesting possibilities for biomedical applications. This microstructuring technique is suitable with many biocompatible polymeric materials, such as polyethylene glycol, polylactic acid, polycaprolactone, gelatin, zirconium-based hybrids, and others. The process of fabrication does not require clean room conditions and does not use hazard chemicals or high temperatures. The most beneficial property of 2PP is that it is capable of producing especially complex three-dimensional (3-D) structures, including devices with overhangs, without using any supportive structure. The flexibility in controlling geometries and feature sizes and the possibility to fabricate structures without the addition of new material layers makes this technique particularly appealing for fabrication of 3-D scaffolds for tissue engineering. PMID:23729598

  6. Maintenance of a bone collagen phenotype by osteoblast-like cells in 3D periodic porous titanium (Ti-6Al-4 V) structures fabricated by selective electron beam melting

    PubMed Central

    Hrabe, Nikolas W.; Heinl, Peter; Bordia, Rajendra K.; Körner, Carolin; Fernandes, Russell J.

    2013-01-01

    Regular 3D periodic porous Ti-6Al-4 V structures were fabricated by the selective electron beam melting method (EBM) over a range of relative densities (0.17–0.40) and pore sizes (500–1500 μm). Structures were seeded with human osteoblast-like cells (SAOS-2) and cultured for four weeks. Cells multiplied within these structures and extracellular matrix collagen content increased. Type I and type V collagens typically synthesized by osteoblasts were deposited in the newly formed matrix with time in culture. High magnification scanning electron microscopy revealed cells attached to surfaces on the interior of the structures with an increasingly fibrous matrix. The in-vitro results demonstrate that the novel EBM-processed porous structures, designed to address the effect of stress-shielding, are conducive to osteoblast attachment, proliferation and deposition of a collagenous matrix characteristic of bone. PMID:23869614

  7. Efficacy of rhBMP-2 loaded PCL/PLGA/β-TCP guided bone regeneration membrane fabricated by 3D printing technology for reconstruction of calvaria defects in rabbit.

    PubMed

    Shim, Jin-Hyung; Yoon, Min-Chul; Jeong, Chang-Mo; Jang, Jinah; Jeong, Sung-In; Cho, Dong-Woo; Huh, Jung-Bo

    2014-12-01

    We successfully fabricated a three-dimensional (3D) printing-based PCL/PLGA/β-TCP guided bone regeneration (GBR) membrane that slowly released rhBMP-2. To impregnate the GBR membrane with intact rhBMP-2, collagen solution encapsulating rhBMP-2 (5 µg ml(-1)) was infused into pores of a PCL/PLGA/β-TCP membrane constructed using a 3D printing system with four dispensing heads. In a release profile test, sustained release of rhBMP-2 was observed for up to 28 d. To investigate the efficacy of the GBR membrane on bone regeneration, PCL/PLGA/β-TCP membranes with or without rhBMP-2 were implanted in an 8 mm calvaria defect of rabbits. Bone formation was evaluated at weeks 4 and 8 histologically and histomorphometrically. A space making ability of the GBR membrane was successfully maintained in both groups, and significantly more new bone was formed at post-implantation weeks 4 and 8 by rhBMP-2 loaded GBR membranes. Interestingly, implantation with rhBMP-2 loaded GBR membranes led to almost entire healing of calvaria defects within 8 weeks. PMID:25384105

  8. Femtosecond fiber laser additive manufacturing and welding for 3D manufacturing

    NASA Astrophysics Data System (ADS)

    Huang, Huan; Nie, Bai; Wan, Peng; Yang, Lih-Mei; Bai, Shuang; Liu, Jian

    2015-03-01

    Due to the unique ultra-short pulse duration and high peak power, femtosecond (fs) laser has emerged as a powerful tool for many applications but has rarely been studied for 3D printing. In this paper, welding of both bulk and powder materials is demonstrated for the first time by using high energy and high repetition rate fs fiber lasers. It opens up new scenarios and opportunities for 3D printing with the following advantages - greater range of materials especially with high melting temperature, greater-than-ever level of precision (sub-micron) and less heat-affected-zone (HAZ). Mechanical properties (strength and hardness) and micro-structures (grain size) of the fabricated parts are investigated. For dissimilar materials bulk welding, good welding quality with over 210 MPa tensile strength is obtained. Also full melting of the micron-sized refractory powders with high melting temperature (above 3000 degree C) is achieved for the first time. 3D parts with shapes like ring and cube are fabricated. Not only does this study explore the feasibility of melting dissimilar and high melting temperature materials using fs lasers, but it also lays out a solid foundation for 3D printing of complex structure with designed compositions, microstructures and properties. This can greatly benefit the applications in automobile, aerospace and biomedical industries, by producing parts like nozzles, engines and miniaturized biomedical devices.

  9. 3-D Technology Approaches for Biological Ecologies

    NASA Astrophysics Data System (ADS)

    Liu, Liyu; Austin, Robert; U. S-China Physical-Oncology Sciences Alliance (PS-OA) Team

    Constructing three dimensional (3-D) landscapes is an inevitable issue in deep study of biological ecologies, because in whatever scales in nature, all of the ecosystems are composed by complex 3-D environments and biological behaviors. Just imagine if a 3-D technology could help complex ecosystems be built easily and mimic in vivo microenvironment realistically with flexible environmental controls, it will be a fantastic and powerful thrust to assist researchers for explorations. For years, we have been utilizing and developing different technologies for constructing 3-D micro landscapes for biophysics studies in in vitro. Here, I will review our past efforts, including probing cancer cell invasiveness with 3-D silicon based Tepuis, constructing 3-D microenvironment for cell invasion and metastasis through polydimethylsiloxane (PDMS) soft lithography, as well as explorations of optimized stenting positions for coronary bifurcation disease with 3-D wax printing and the latest home designed 3-D bio-printer. Although 3-D technologies is currently considered not mature enough for arbitrary 3-D micro-ecological models with easy design and fabrication, I hope through my talk, the audiences will be able to sense its significance and predictable breakthroughs in the near future. This work was supported by the State Key Development Program for Basic Research of China (Grant No. 2013CB837200), the National Natural Science Foundation of China (Grant No. 11474345) and the Beijing Natural Science Foundation (Grant No. 7154221).

  10. TRACE 3-D documentation

    SciTech Connect

    Crandall, K.R.

    1987-08-01

    TRACE 3-D is an interactive beam-dynamics program that calculates the envelopes of a bunched beam, including linear space-charge forces, through a user-defined transport system. TRACE 3-D provides an immediate graphics display of the envelopes and the phase-space ellipses and allows nine types of beam-matching options. This report describes the beam-dynamics calculations and gives detailed instruction for using the code. Several examples are described in detail.

  11. 3D RoboMET Characterization

    SciTech Connect

    Madison, Jonathan D.; Susan, Donald F.; Kilgo, Alice C.

    2015-10-01

    The goal of this project is to generate 3D microstructural data by destructive and non-destructive means and provide accompanying characterization and quantitative analysis of such data. This work is a continuing part of a larger effort to relate material performance variability to microstructural variability. That larger effort is called “Predicting Performance Margins” or PPM. In conjunction with that overarching initiative, the RoboMET.3D™ is a specific asset of Center 1800 and is an automated serialsectioning system for destructive analysis of microstructure, which is called upon to provide direct customer support to 1800 and non-1800 customers. To that end, data collection, 3d reconstruction and analysis of typical and atypical microstructures have been pursued for the purposes of qualitative and quantitative characterization with a goal toward linking microstructural defects and/or microstructural features with mechanical response. Material systems examined in FY15 include precipitation hardened 17-4 steel, laser-welds of 304L stainless steel, thermal spray coatings of 304L and geological samples of sandstone.

  12. Laser nanolithography and chemical metalization for the manufacturing of 3D metallic interconnects

    NASA Astrophysics Data System (ADS)

    Jonavičius, Tomas; RekštytÄ--, Sima; Žukauskas, Albertas; Malinauskas, Mangirdas

    2014-03-01

    We present a developed method based on direct laser writing (DLW) and chemical metallization (CM) for microfabrication of three-dimensional (3D) metallic structures. Such approach enables manufacturing of free­-form electro conductive interconnects which can be used in integrated electric circuits such micro-opto-electro mechanical systems (MOEMS). The proposed technique employing ultrafast high repetition rate laser enables efficient fabrication of 3D microstructures on dielectric as well as conductive substrates. The produced polymer links out of organic-inorganic composite matrix after CM serve as interconnects of separate metallic contacts, their dimensions are: height 15μm, width 5μm, length 35-45 μm and could provide 300 nΩm resistivity measured in a macroscopic way. This proves the techniques potential for creating integrated 3D electric circuits at microscale.

  13. Microstructured photopolymer films of a ruthenium(II) polypyridine complex: Fabrication of an electrochemically switchable phase grating

    SciTech Connect

    Bergstedt, T.S.; Hauser, B.T.; Schanze, K.S.

    1994-09-07

    Fabrication of thin polymeric films composed of redox-active monomers via electropolymerization is an established technology. Although electropolymerization is a versatile method for preparation of films containing multiple chemical sites or multilayer films in which each layer comprises chemically distinct monomer units, the method does not afford a direct means to create films that are patterned within the plane of the substrate. By contrast, photolithography provides a means to fabricate thin polymer films that are structured in 2-D patterns with micron and submicron spatial resolutions. Reported is a unique application of photolithography to fabricate microstructured electroactive polymer films that are adsorbed to an optically transparent, conducting substrate. Using polypyridyl-Ru(II) monomers, films were prepared and fabricated into an optical diffraction grating that can be electrochemically modulated. It was found that the origin of the electrochmically-induced modulation in the diffraction efficiency is likely due to a change in the refractive index of the film which is coupled with the Ru(II/III) oxidation/reduction. 23 refs., 2 figs.

  14. 3D-patterned polymer brush surfaces

    NASA Astrophysics Data System (ADS)

    Zhou, Xuechang; Liu, Xuqing; Xie, Zhuang; Zheng, Zijian

    2011-12-01

    Polymer brush-based three-dimensional (3D) structures are emerging as a powerful platform to engineer a surface by providing abundant spatially distributed chemical and physical properties. In this feature article, we aim to give a summary of the recent progress on the fabrication of 3D structures with polymer brushes, with a particular focus on the micro- and nanoscale. We start with a brief introduction on polymer brushes and the challenges to prepare their 3D structures. Then, we highlight the recent advances of the fabrication approaches on the basis of traditional polymerization time and grafting density strategies, and a recently developed feature density strategy. Finally, we provide some perspective outlooks on the future directions of engineering the 3D structures with polymer brushes.

  15. Fabrication of 3D carbon nanotube networks

    NASA Astrophysics Data System (ADS)

    Laera, Anna Maria; Mirenghi, Luciana; Schioppa, Monica; Nobile, Concetta; Capodieci, Laura; Grazia Scalone, Anna; Di Benedetto, Francesca; Tapfer, Leander

    2016-08-01

    We report on the synthesis and characterization of a hyperbranched polymer englobing single-wall carbon nanotubes (SWCNTs). This new material was obtained by using SWCNTs functionalized with carboxylic groups as starting reagent. The acid groups were firstly converted in acyl chloride moieties and afterwards were bound to hexamethylenediamine (HMDA) via formation of amide functionality. The acquired spectra of attenuated total reflectance and the analysis performed through x-ray photoelectron spectroscopy confirmed the amide bond formation. The hyperbranched polymer characterization was completed by using scanning and transmission electron microscopy, thermo-gravimetric analysis and Raman spectroscopy. The electron microscopy analyses showed the formation of an amorphous polymeric material englobing a dense network of SWCNTs without phase segregation, demonstrating that the reaction with HMDA allows a reorganization of SWCNTs in a complex three-dimensional network.

  16. Microstructured Nickel-Titanium Thin Film Leaflets for Hybrid Tissue Engineered Heart Valves Fabricated by Magnetron Sputter Deposition.

    PubMed

    Loger, K; Engel, A; Haupt, J; Lima de Miranda, R; Lutter, G; Quandt, E

    2016-03-01

    Heart valves are constantly exposed to high dynamic loading and are prone to degeneration. Therefore, it is a challenge to develop a durable heart valve substitute. A promising approach in heart valve engineering is the development of hybrid scaffolds which are composed of a mechanically strong inorganic mesh enclosed by valvular tissue. In order to engineer an efficient, durable and very thin heart valve for transcatheter implantations, we developed a fabrication process for microstructured heart valve leaflets made from a nickel-titanium (NiTi) thin film shape memory alloy. To examine the capability of microstructured NiTi thin film as a matrix scaffold for tissue engineered hybrid heart valves, leaflets were successfully seeded with smooth muscle cells (SMCs). In vitro pulsatile hydrodynamic testing of the NiTi thin film valve leaflets demonstrated that the SMC layer significantly improved the diastolic sufficiency of the microstructured leaflets, without affecting the systolic efficiency. Compared to an established porcine reference valve model, magnetron sputtered NiTi thin film material demonstrated its suitability for hybrid tissue engineered heart valves. PMID:26743538

  17. Effect of Heat Treatment on Microstructure and Mechanical Properties of Inconel 625 Alloy Fabricated by Pulsed Plasma Arc Deposition

    NASA Astrophysics Data System (ADS)

    Xu, Fujia; Lv, Yaohui; Liu, Yuxin; Xu, Binshi; He, Peng

    Pulsed plasma arc deposition (PPAD) was successfully used to fabricate the Ni-based superalloy Inconel 625 samples. The effects of three heat treatment technologies on microstructure and mechanical properties of the as-deposited material were investigated. It was found that the as-deposited structure exhibited homogenous cellular dendrite structure, which grew epitaxially along the deposition direction. Moreover, some intermetallic phases including Laves phase and MC carbides were precipitated in the interdendritic region as a result of Nb segregation. Compared with the as-deposited microstructure, the direct aged (DA) microstructure changed little except the precipitation of hardening phases γ' and γ" (Ni3Nb), which enhanced the hardness and tensile strength. But the plastic property was inferior due to the existence of brittle Laves phase. After solution and aging heat treatment (STA), a large amount of Laves particles in the interdendritic regions were dissolved, resulting in the reduction of Nb segregation and the precipitation of needle-like δ (Ni3Nb) in the interdendritic regions and grain boundaries. The hardness and tensile strength were improved without sacrificing the ductility. By homogenization and STA heat treatment (HSTA), Laves particles were dissolved into the matrix completely and resulted in recrystallized large grains with bands of annealing twins. The primary MC particles and remaining phase still appeared in the matrix and grain boundaries. Compared with the as-deposited sample, the mechanical properties decreased severely as a result of the grain growth coarsening. The failure modes of all the tensile specimens were analyzed with fractography.

  18. Microstructural characterization of weld joints of 9Cr reduced activation ferritic martensitic steel fabricated by different joining methods

    SciTech Connect

    Thomas Paul, V.; Saroja, S.; Albert, S.K.; Jayakumar, T.; Rajendra Kumar, E.

    2014-10-15

    This paper presents a detailed electron microscopy study on the microstructure of various regions of weldment fabricated by three welding methods namely tungsten inert gas welding, electron beam welding and laser beam welding in an indigenously developed 9Cr reduced activation ferritic/martensitic steel. Electron back scatter diffraction studies showed a random micro-texture in all the three welds. Microstructural changes during thermal exposures were studied and corroborated with hardness and optimized conditions for the post weld heat treatment have been identified for this steel. Hollomon–Jaffe parameter has been used to estimate the extent of tempering. The activation energy for the tempering process has been evaluated and found to be corresponding to interstitial diffusion of carbon in ferrite matrix. The type and microchemistry of secondary phases in different regions of the weldment have been identified by analytical transmission electron microscopy. - Highlights: • Comparison of microstructural parameters in TIG, electron beam and laser welds of RAFM steel • EBSD studies to illustrate the absence of preferred orientation and identification of prior austenite grain size using phase identification map • Optimization of PWHT conditions for indigenous RAFM steel • Study of kinetics of tempering and estimation of apparent activation energy of the process.

  19. Quantification of the microstructural evolution of polycrystalline fabrics using FAME: Application to in situ deformation of ice

    NASA Astrophysics Data System (ADS)

    Peternell, Mark; Dierckx, Marie; Wilson, Christopher J. L.; Piazolo, Sandra

    2014-04-01

    In geology, glaciology and material science new technological advances result in an ever increasing amount of data and datasets, in particular when in situ experiments are conducted. Rapid, rigorous and reliable statistical treatment is needed to allow researchers to access these large datasets for further analysis. Here, we present FAME (Fabric Analyser based Microstructure Evaluation), a suite of Matlab® scripts that utilize the Matlab® open-source toolboxes MTEX and PolyLX (optional) for rapid quantification of thin section data. The data has been collected using an automated Fabric Analyser at a spatial resolution of 5 μm/pixel. From the dataset, grain maps are reconstructed and, grain and grain boundary statistics are determined. The same scripts calculate orientation density distribution diagrams and eigenvalues of the orientation tensor. In the case of 2D in situ plane-strain deformation experiments on polycrystalline heavy water (D2O), a Matlab® script-based batch analysis for each deformation step was performed. FAME offers the possibility to generate movie files that combine optical data with c-axes orientation data and grain statistics. Application of the presented scripts, to analyse in situ deformation experiments of polycrystalline ice, shows the value of rigorous quantification of the microstructural evolution data for process oriented research.

  20. Experiment and simulation of the fabrication process of lithium-ion battery cathodes for determining microstructure and mechanical properties

    NASA Astrophysics Data System (ADS)

    Forouzan, Mehdi M.; Chao, Chien-Wei; Bustamante, Danilo; Mazzeo, Brian A.; Wheeler, Dean R.

    2016-04-01

    The fabrication process of Li-ion battery electrodes plays a prominent role in the microstructure and corresponding cell performance. Here, a mesoscale particle dynamics simulation is developed to relate the manufacturing process of a cathode containing Toda NCM-523 active material to physical and structural properties of the dried film. Particle interactions are simulated with shifted-force Lennard-Jones and granular Hertzian functions. LAMMPS, a freely available particle simulator, is used to generate particle trajectories and resulting predicted properties. To make simulations of the full film thickness feasible, the carbon binder domain (CBD) is approximated with μm-scale particles, each representing about 1000 carbon black particles and associated binder. Metrics for model parameterization and validation are measured experimentally and include the following: slurry viscosity, elasticity of the dried film, shrinkage ratio during drying, volume fraction of phases, slurry and dried film densities, and microstructure cross sections. Simulation results are in substantial agreement with experiment, showing that the simulations reasonably reproduce the relevant physics of particle arrangement during fabrication.

  1. Microstructure and Mechanical Properties of Titanium Components Fabricated by a New Powder Injection Molding Technique

    SciTech Connect

    Nyberg, Eric A.; Miller, Megan R.; Simmons, Kevin L.; Weil, K. Scott

    2005-05-01

    We have developed a powder injection molding (PIM) binder system for titanium that employs naphthalene as the primary constituent to facilitate easy binder removal and mitigate problems with carbon contamination. In the study presented here, we examined densification behavior, microstructure, and mechanical properties in specimens formed by this process. In general, we found that we could achieve tensile strengths comparable to wrought titanium in the PIM-formed specimens, but that maximum elongation was less than expected. Chemical and microstructural analyses suggest that use of higher purity powder and further process optimization will lead to significant improvements in ductility.

  2. Mesoscale 3D manufacturing: varying focusing conditions for efficient direct laser writing of polymers

    NASA Astrophysics Data System (ADS)

    Jonušauskas, Linas; Malinauskas, Mangirdas

    2014-05-01

    In this paper, we report a novel approach for efficient fabrication of mesoscale polymer 3D microstructures. It is implemented by direct laser writing varying exposure beam focusing conditions. By carefully optimizing the fabrication parameters (laser intensity, scanning velocity/exposure time, changing objective lens) complex 3D geometries of the microstructures can be obtained rapidly. Additionally, we demonstrate this without the use of the photoinitiator as photosensitizer doped in the pre-polymer material (SZ2080). At femtosecond pulsed irradiation ~TW/cm² intensities the localized free radical polymerization is achieved via avalanche induced bond braking. Such microstructures have unique biocompatibility and optical transparency as well as optical damage threshold value. By creating the bulk part of the structure using low-NA (0.45) objective and subsequently fabricating the fine features using oil immersion high-NA (1.4) objective the manufacturing time is reduced dramatically (30x is demonstrated). Using this two objective method a prototype of functional microdevice was produced: 80 and 85 µm diameter microfluidic tubes with the fine filter consisting of 4 µm period grating structure that has 400 nm wide threads, which corresponds to a feature precision aspect ratio of ~200. Therefore, such method has great potential as a polymer fabrication tool for mesoscale optical, photonic and biomedical applications as well as highly integrated 3D µ-systems. Furthermore, the proposed approach is not limited to lithography and can be implemented in a more general type of laser writing, such as inscription within transparent materials or substractive manufacturing by ablation.

  3. Radiochromic 3D Detectors

    NASA Astrophysics Data System (ADS)

    Oldham, Mark

    2015-01-01

    Radiochromic materials exhibit a colour change when exposed to ionising radiation. Radiochromic film has been used for clinical dosimetry for many years and increasingly so recently, as films of higher sensitivities have become available. The two principle advantages of radiochromic dosimetry include greater tissue equivalence (radiologically) and the lack of requirement for development of the colour change. In a radiochromic material, the colour change arises direct from ionising interactions affecting dye molecules, without requiring any latent chemical, optical or thermal development, with important implications for increased accuracy and convenience. It is only relatively recently however, that 3D radiochromic dosimetry has become possible. In this article we review recent developments and the current state-of-the-art of 3D radiochromic dosimetry, and the potential for a more comprehensive solution for the verification of complex radiation therapy treatments, and 3D dose measurement in general.

  4. Microstructural and Chemical Reappraisal of Mineralogical Inheritance in Partially Molten Rocks: Implication for Fabric Resetting in Granitoids

    NASA Astrophysics Data System (ADS)

    Hasalova, P.; Schulmann, K.; Tabaud, A.; Verner, K.; Weinberg, R. F.

    2013-12-01

    During orogenic processes continental crust experience significant partial melting. Repeated thermal pulses or fluctuation in water content can even cause multiple anatectic events that result in complex intrusion suits. There are numerous studies regarding chronology of such intrusions or origin of the magmas. However, there is lack of microstructural characteristic of such remelting/infiltration processes. How do we distinguish the newly derived melt from the inherited magmatic crystals? What is the resulting microstructural appearance of such 'mixed' granite? And importantly how does new melt presence impact on fabric recorded in these granites? We investigate extensive granitoids complex in the Vosges Mountains in Eastern France. This complex reveal two main generations of magmatic rocks. The first event occurred at ca. 340Ma, is associated with extensive Mg-K magmatism and is related to building of thick orogenic root and subsequent exhumation of deep crust to shallower crustal levels. These granitoids intruded all crustal levels. The second magmatic event occurred at ca. 325 Ma and affected exclusively the mid-crustal level. This magmatic event produced large quantity of felsic anatectic melts which further pervasively intruded and compositionally and texturally reworked previously formed magmas. The detailed field and microstructural observations revealed a transition from granites that has been completely reworked by the infiltrated melt to granites that preserve former magmatic assemblage and have only incipient amount of the new melt. The new from melt crystallized material form narrow, fine-grained pathways along grain boundaries or cuts across pre-existing magmatic grains. With increasing amount of the newly crystallized material the original magmatic xenocrysts are resorbed and show highly corroded shapes. The early formed feldspar and quartz grains have strong compositional zoning, with cores reflecting original magmatic composition and rims showing

  5. Understanding the microstructure and properties of components fabricated by laser engineered net shaping (LENS)

    SciTech Connect

    GRIFFITH,MICHELLE L.; ENSZ,MARK T.; PUSKAR,JOSEPH D.; ROBINO,CHARLES V.; BROOKS,JOHN A.; PHILLIBER,JOEL A.; SMUGERESKY,JOHN E.; HOFMEISTER,W.H.

    2000-05-18

    Laser Engineered Net Shaping (LENS) is a novel manufacturing process for fabricating metal parts directly from Computer Aided Design (CAD) solid models. The process is similar to rapid prototyping technologies in its approach to fabricate a solid component by layer additive methods. However, the LENS technology is unique in that fully dense metal components with material properties that are similar to that of wrought materials can be fabricated. The LENS process has the potential to dramatically reduce the time and cost required realizing functional metal parts. In addition, the process can fabricate complex internal features not possible using existing manufacturing processes. The real promise of the technology is the potential to manipulate the material fabrication and properties through precision deposition of the material, which includes thermal behavior control, layered or graded deposition of multi-materials, and process parameter selection. This paper describes the authors' research to understand solidification aspects, thermal behavior, and material properties for laser metal deposition technologies.

  6. Biocompatible 3D Matrix with Antimicrobial Properties.

    PubMed

    Ion, Alberto; Andronescu, Ecaterina; Rădulescu, Dragoș; Rădulescu, Marius; Iordache, Florin; Vasile, Bogdan Ștefan; Surdu, Adrian Vasile; Albu, Madalina Georgiana; Maniu, Horia; Chifiriuc, Mariana Carmen; Grumezescu, Alexandru Mihai; Holban, Alina Maria

    2016-01-01

    The aim of this study was to develop, characterize and assess the biological activity of a new regenerative 3D matrix with antimicrobial properties, based on collagen (COLL), hydroxyapatite (HAp), β-cyclodextrin (β-CD) and usnic acid (UA). The prepared 3D matrix was characterized by Scanning Electron Microscopy (SEM), Fourier Transform Infrared Microscopy (FT-IRM), Transmission Electron Microscopy (TEM), and X-ray Diffraction (XRD). In vitro qualitative and quantitative analyses performed on cultured diploid cells demonstrated that the 3D matrix is biocompatible, allowing the normal development and growth of MG-63 osteoblast-like cells and exhibited an antimicrobial effect, especially on the Staphylococcus aureus strain, explained by the particular higher inhibitory activity of usnic acid (UA) against Gram positive bacterial strains. Our data strongly recommend the obtained 3D matrix to be used as a successful alternative for the fabrication of three dimensional (3D) anti-infective regeneration matrix for bone tissue engineering. PMID:26805790

  7. Bootstrapping 3D fermions

    NASA Astrophysics Data System (ADS)

    Iliesiu, Luca; Kos, Filip; Poland, David; Pufu, Silviu S.; Simmons-Duffin, David; Yacoby, Ran

    2016-03-01

    We study the conformal bootstrap for a 4-point function of fermions < ψψψψ> in 3D. We first introduce an embedding formalism for 3D spinors and compute the conformal blocks appearing in fermion 4-point functions. Using these results, we find general bounds on the dimensions of operators appearing in the ψ × ψ OPE, and also on the central charge C T . We observe features in our bounds that coincide with scaling dimensions in the GrossNeveu models at large N . We also speculate that other features could coincide with a fermionic CFT containing no relevant scalar operators.

  8. Two-photon polymerization microfabrication of hydrogels: an advanced 3D printing technology for tissue engineering and drug delivery.

    PubMed

    Xing, Jin-Feng; Zheng, Mei-Ling; Duan, Xuan-Ming

    2015-08-01

    3D printing technology has attracted much attention due to its high potential in scientific and industrial applications. As an outstanding 3D printing technology, two-photon polymerization (TPP) microfabrication has been applied in the fields of micro/nanophotonics, micro-electromechanical systems, microfluidics, biomedical implants and microdevices. In particular, TPP microfabrication is very useful in tissue engineering and drug delivery due to its powerful fabrication capability for precise microstructures with high spatial resolution on both the microscopic and the nanometric scale. The design and fabrication of 3D hydrogels widely used in tissue engineering and drug delivery has been an important research area of TPP microfabrication. The resolution is a key parameter for 3D hydrogels to simulate the native 3D environment in which the cells reside and the drug is controlled to release with optimal temporal and spatial distribution in vitro and in vivo. The resolution of 3D hydrogels largely depends on the efficiency of TPP initiators. In this paper, we will review the widely used photoresists, the development of TPP photoinitiators, the strategies for improving the resolution and the microfabrication of 3D hydrogels. PMID:25992492

  9. SU-8 Lenses: Simple Methods of Fabrication and Application in Optical Interconnection Between Fiber/LED and Microstructures

    NASA Astrophysics Data System (ADS)

    Nguyen, Minh-Hang; Nguyen, Hai-Binh; Nguyen, Tuan-Hung; Vu, Xuan-Manh; Lai, Jain-Ren; Tseng, Fan-Gang; Chen, Te-Chang; Lee, Ming-Chang

    2016-05-01

    This paper presents two facile methods to fabricate off-plane lenses made of SU-8, an epoxy-based negative photoresist from MicroChem, on glass for optical interconnection. The methods allow the fabrication of lenses with flexible spot size and focal length depending on SU-8 well size and SU-8 drop volume and viscosity. In the first method, SU-8 drops were applied directly into patterned SU-8 wells with Teflon-coated micropipettes, and were baked to become (a)-spherical lenses. The lens shape and size were mainly determined by SU-8 viscosity, ratio of drop volume to well volume, and baking temperature and time. In the second method, a glass substrate with SU-8 patterned wells was emerged in diluted SU-8, then drawn up and baked to form lenses. The lens shapes and sizes were mainly determined by SU-8 viscosity and well volume. By the two methods, SU-8 lenses were successfully fabricated with spot sizes varying in range from micrometers to hundred micrometers, and focal lengths varying in range of several millimeters, depending on the lens rim diameters and aspheric sag height. Besides, on-plane SU-8 lenses were fabricated by photolithography to work in conjunction with the off-plane SU-8 lenses. The cascaded lenses produced light spots reduced to several micrometers, and they can be applied as a coupler for light coupling from fiber/Light-emitting diode (LED) to microstructures and nanostructures. The results open up the path for fabricating novel optical microsystems for optical communication and optical sensing applications.

  10. “Pop-slide” patterning: Rapid fabrication of microstructured PDMS gasket slides for biological applications

    PubMed Central

    Ramji, Ramesh; Khan, Nafeesa T; Muñoz-Rojas, Andrés; Miller-Jensen, Kathryn

    2015-01-01

    We describe a “pop-slide” patterning approach to easily produce thin film microstructures on the surface of glass with varying feature sizes (3 μm – 250 μm) and aspect ratios (0.066 – 3) within 45 minutes. This low cost method does not require specialized equipment while allowing us to produce micro structured gasket layers for sandwich assays and could be readily applied to many biological applications. PMID:26949529

  11. Fabrication, Micro-structural Analysis, and Mechanical Testing of High Density Polymeric Foam

    NASA Astrophysics Data System (ADS)

    Marks, Trevor Gustov

    Foams, or what are often called cellular solids, are some of the most widely used materials in the modern era. In general, foam is a porous substance formed by the introduction of gas filled pores into condensed matter; the result is typically a light weight substance with properties related to the base (non-porous) medium. Applications of foams include: vibration dampening, energy mitigation (such as packaging and bike helmets), insulation, filtration, and flotation. The focus of this work is on the properties of flexible elastomeric foam of high relative-density. The bulk of existing literature on elastomeric foam is concerned with foam of low relative-density (ratio of the foam density to the density of the material from which the foam is formed ≤ 0.1). The relationship between the micro-structure of high relative-density foam and its mechanical response has, in large part, not been subjected to systematic investigation heretofore. The present work examines how the micro-structural features of pore shape, size, and location affect the macro-structural response of relative high density foam to compressive loading. In order to carry out this study, methods were developed and employed to control a foam's micro-structure, and hence its mechanical response, with the use of temporary pore forming particles and micron scale inclusions. Advanced microscopy techniques were used to observe, in situ, the evolution of a foam's micro-structure under compressive loading, and the results were correlated with the evolution of the foam's stress - strain response. Additionally, quantitative methods were developed and employed to describe numerically the foam's micro-structural features, such as: (i), pore shape, (ii), pore size, and (iii), the arrangement of the pores with respect to each other. Numerous foams were produced, tested, and subjected to the

  12. Fabrication of PbS microstructures with different shapes in aqueous solutions of amphiphilic triblock copolymer

    NASA Astrophysics Data System (ADS)

    Ding, Yuanhua; Liu, Xiaoxia; Guo, Rong

    2007-09-01

    Hollow PbS nanospheres and branch-like PbS microstructures have been successfully synthesized by the reaction of Pb(Ac) 2 with the S 2- ions released slowly from thioacetamide (TAA) in Pluronic F127 aqueous solutions at room temperature. The obtained hollow PbS nanospheres have a wall thickness of about 40 nm, and the branch-like PbS microstructures have an average size of 0.7-2.2 μm. Both the wall of the hollow PbS nanospheres and the branch-like structures consist of cubic PbS nanocrystallites. It has been found that a minimum F127 concentration is required for the formation of hollow and branch-like PbS structures. With increasing F127 concentration, the diameter of the obtained hollow spheres increases gradually, whereas the size of the branch-like structures decreases. The addition of cyclohexane makes the diameter of hollow spheres decrease, but has little effect on the branch-like structures. Increasing the temperature of the solutions can significantly decrease the sizes of the hollow and branch-like structures. The complex micelles formed by Pb(Ac) 2 and F127 micelles act as soft templates for the formation of hollow PbS nanospheres, and the complex monomeric F127 aggregates formed by Pb(Ac) 2 and monomeric F127 chains play a structure-directing role in the formation of branch-like PbS microstructures.

  13. Magnetic CoFe2O4/carbon nanotubes composites: fabrication, microstructure and magnetic response

    NASA Astrophysics Data System (ADS)

    Wang, Panfeng; Xu, Jingcai; Han, Yanbing; Hong, Bo; Jin, Hongxiao; Jin, Dingfeng; Peng, Xiaoling; Li, Jing; Ge, Hongliang; Wang, Xinqing

    2014-05-01

    By combining the unique microstructure of carbon nanotubes (CNTs) with the good magnetism of CoFe2O4 ferrites, CoFe2O4/CNTs nanocomposites were prepared by the solvothermal method for the application of targeting therapy and tumor hyperthermia. X-ray diffraction (XRD), thermal gravity analysis (TGA), transmission electron microscope (TEM) and vibrating sample magnetometer (VSM) were introduced to study the influence of the solvothermal temperature, time and the CNTs content on the microstructure and magnetic properties of CoFe2O4/CNTs nanocomposites. The diameter of CoFe2O4 nanoparticles coating on the surface of CNTs and the saturation magnetization (Ms) increased with the solvothermal temperature. CoFe2O4/CNTs nanocomposites prepared at 180°C, 200°C and 220°C exhibited superparamagnetism at room temperature, while the samples prepared at 240°C and 260°C presented ferromagnetism. And the solvothermal time and CNTs content slightly affected the microstructure and magnetic properties, Ms and coercivity (Hc) increased slightly with the increasing solvothermal time and the decreasing CNTs content.

  14. 3D optical printing of piezoelectric nanoparticle-polymer composite materials.

    PubMed

    Kim, Kanguk; Zhu, Wei; Qu, Xin; Aaronson, Chase; McCall, William R; Chen, Shaochen; Sirbuly, Donald J

    2014-10-28

    Here we demonstrate that efficient piezoelectric nanoparticle-polymer composite materials can be optically printed into three-dimensional (3D) microstructures using digital projection printing. Piezoelectric polymers were fabricated by incorporating barium titanate (BaTiO3, BTO) nanoparticles into photoliable polymer solutions such as polyethylene glycol diacrylate and exposing to digital optical masks that could be dynamically altered to generate user-defined 3D microstructures. To enhance the mechanical-to-electrical conversion efficiency of the composites, the BTO nanoparticles were chemically modified with acrylate surface groups, which formed direct covalent linkages with the polymer matrix under light exposure. The composites with a 10% mass loading of the chemically modified BTO nanoparticles showed piezoelectric coefficients (d(33)) of ∼ 40 pC/N, which were over 10 times larger than composites synthesized with unmodified BTO nanoparticles and over 2 times larger than composites containing unmodified BTO nanoparticles and carbon nanotubes to boost mechanical stress transfer efficiencies. These results not only provide a tool for fabricating 3D piezoelectric polymers but lay the groundwork for creating highly efficient piezoelectric polymer materials via nanointerfacial tuning. PMID:25046646

  15. Fabrication of highly oriented microstructures and nanostructures of ferroelectric P(VDF-TrFE) copolymer via dip-pen nanolithography

    NASA Astrophysics Data System (ADS)

    Tang, Qian; Shi, San-qiang; Huang, Haitao; Zhou, Li Min

    2004-07-01

    Microstructures and nanostructures of ferroelectric copolymer poly(vinylidene fluoride-trifluorethylene) [P(VDF-TrFE)] are fabricated on gold via dip-pen nanolithography (DPN). The thickness of the patterns is about 1 nm after a critical concentration, regardless of the pattern scale. The polymer molecules are well orientated according to an all- trans conformation and have ferroelectric properties on the gold surface through electrostatic interaction, rather than the formation of chemical bonds. Increasing temperature has a positive effect on the growth rate of the P(VDF-TrFE). The electrostatic interaction between the P(VDF-TrFE) and the gold substrate and the intramolecular interaction of polymer molecules play important roles in the growth rate of the P(VDF-TrFE) patterns.

  16. Microstructure and properties of silicon-incorporated DLC film fabricated using HMDS gas and RF-PECVD process.

    PubMed

    Song, Byung Ju; Song, Woo Jin; Han, Jun Hyun; Kim, Ka Ram; Yoon, Su Jong; Kim, Tae Gyu; Kim, Jin Kon; Cho, Hyun; Kim, Gyeung-Ho; Hwang, Dae Youn; Kim, Hye Sung

    2014-12-01

    The microstructure and characteristics of silicon-incorporated diamond-like carbon film, fabricated using a radio-frequency plasma-enhanced chemical vapor deposition process with hexamethyldisilane [(CH3)3,Si x Si(CH3)3:HMDS] gas as a silicon source, were investigated. Diamond-like carbon films with silicon compositions from 0 to 5 atomic percent were deposited onto ultra-fine grained AZ31 magnesium alloy substrate as buffer layers or multilayers. Si doping led not only to an increase in the bonding ratio (sp3/sp2), but improvements in hardness, critical adhesion, and corrosion resistance. Out of the investigated samples, the multi-deposited silicon diamond-like carbon thin film on magnesium substrate showed the best combination of adhesive, wear resistance, and corrosion resistance properties. PMID:25971022

  17. Influence of ambient gas on the microstructural properties of Er-doped nanocrystalline Si film fabricated by pulsed laser ablation

    NASA Astrophysics Data System (ADS)

    Zhou, Yang; Chu, Lizhi; Duan, Pingguang; Xu, Wei; Wang, Yinglong; F, Guangsheng

    2007-12-01

    Er-doped nanocrystalline Si thin films were fabricated by pulsed laser ablation in high-purity Ar gas with different gas pressures at room temperature and post-annealing technology under different temperature in nitrogen. Scanning electron microscopy(SEM), x-ray diffraction(XRD) and Raman were employed to picture the microstructure of films. The SEM photographs showed that the morphology of film was transformed from the uniform nanoparticles in size to the web-like structure with the increase of gas pressure, which was attributed to the different collision cooling process of ablated particles. Raman and XRD spectra showed that the introduction of Ar gas could effectively improve the crystallinity degree of the samples and Si nanoparticle size could be controlled by adjusting the post-annealing temperature which was critical for improving the luminescent intensity of Er 3+ ion. More uniform and higher crystallinity degree Er-doped Si thin films could be obtained at lower annealing temperature.

  18. Fabrication and Evaluation of PLLA Multichannel Conduits with Nanofibrous Microstructure for the Differentiation of NSCs In Vitro

    PubMed Central

    Zeng, Chen-guang; Xiong, Yi; Xie, Gaoyi; Dong, Peng

    2014-01-01

    Nerve conduits (NCs) with multiple longitudinally aligned channels, being mimicking the natural nerves anatomical structure, have been attracted more and more attentions. However, some specific structural parameters of a conduit that would be beneficial for further improvement of neural tissue regeneration were not comprehensively considered. Using a systematized device and combining low-pressure injection molding and thermal-induced phase separation, we fabricated 33-channel NCs (outer diameter 3.5 mm, channel diameter 200 μm) with different well-defined microscopic features, including NCs with a nano-fibrous microstructure (NNC), NCs with microspherical pores and nano-fibrous pore walls (MNC), and NCs with a ladder-like microstructure (LNC). The porosities of these NCs were ∼90% and were independent of the fine microstructures, whereas the pore size distributions were clearly distinct. The adsorption of bovine serum albumin for the NNC was a result of having the highest specific surface area, which was 3.5 times that of the LNC. But the mechanical strength of NNC was lower than that of two groups because of a relative high crystallinity and brittle characteristics. In vitro nerve stem cells (NSCs) incubation revealed that 14 days after seeding the NSCs, 31.32% cells were Map2 positive in the NNC group, as opposed to 15.76% in the LNC group and 23.29% in the MNC group. Addition of NGF into the culture medium, being distinctive specific surface area and a high adsorption of proteon for NNC, 81.11% of neurons derived from the differentiation of the seeded NSCs was obtained. As a result of imitating the physical structure of the basement membrane of the neural matrix, the nanofibrous structure of the NCs has facilitated the differentiation of NSCs into neurons. PMID:24138342

  19. Microstructure and Mechanical Properties of Al356/SiCp Cast Composites Fabricated by a Novel Technique

    NASA Astrophysics Data System (ADS)

    Amirkhanlou, Sajjad; Niroumand, Behzad

    2013-01-01

    In this study, SiCp containing composite powders were used as the reinforcement carrier media for manufacturing cast Al356/5 vol.% SiCp composites. Untreated SiCp, milled particulate Al-SiCp composite powder, and milled particulate Al-SiCp-Mg composite powder were injected into Al356 melt. The resultant composite slurries were then cast from either a fully liquid state (stir casting) or semisolid state (compocasting). The results revealed that by injection of composite powders, the uniformity of the SiCp in the Al356 matrix was greatly improved, the particle-free zones in the matrix were disappeared, the SiC particles became smaller, the porosity was decreased, and the matrix microstructure became finer. Compocasting changed the matrix dendritic microstructure to a finer non-dendritic one and also slightly improved the distribution of the SiCp. Simultaneous utilization of Al-SiCp-Mg composite powder and compocasting method increased the macro- and micro-hardness, impact energy, bending strength, and bending strain of Al356/SiCp composite by 35, 63, 20, 20, and 40%, respectively, as compared with those of the composite fabricated by injection of untreated SiCp and stir casting process.

  20. Microstructure and mechanical properties of open-cellular biomaterials prototypes for total knee replacement implants fabricated by electron beam melting.

    PubMed

    Murr, L E; Amato, K N; Li, S J; Tian, Y X; Cheng, X Y; Gaytan, S M; Martinez, E; Shindo, P W; Medina, F; Wicker, R B

    2011-10-01

    Total knee replacement implants consisting of a Co-29Cr-6Mo alloy femoral component and a Ti-6Al-4V tibial component are the basis for the additive manufacturing of novel solid, mesh, and foam monoliths using electron beam melting (EBM). Ti-6Al-4V solid prototype microstructures were primarily α-phase acicular platelets while the mesh and foam structures were characterized by α(')-martensite with some residual α. The Co-29Cr-6Mo containing 0.22% C formed columnar (directional) Cr(23)C(6) carbides spaced ~2 μm in the build direction, while HIP-annealed Co-Cr alloy exhibited an intrinsic stacking fault microstructure. A log-log plot of relative stiffness versus relative density for Ti-6Al-4V and Co-29Cr-6Mo open-cellular mesh and foams resulted in a fitted line with a nearly ideal slope, n = 2.1. A stress shielding design graph constructed from these data permitted mesh and foam implant prototypes to be fabricated for compatible bone stiffness. PMID:21783150

  1. Ni/YSZ pattern anodes fabrication and their microstructure and electrochemical behavior changes in H2-H2O environments

    NASA Astrophysics Data System (ADS)

    Yao, W.; Croiset, E.

    2013-03-01

    An effective photolithographic process was investigated to fabricate Ni/YSZ pattern anodes using a bi-layer lift-off resist method. Suitable undercut size was found critical for successful pattern fabrication. Effects of Ni thickness, temperature and H2O content on Ni pattern microstructure were evaluated. Ni/YSZ pattern anodes with 0.5 μm thick Ni was tested in dry H2 at 550 °C without significantly changing the TPB line. Ni/YSZ pattern anodes with Ni thickness of 0.8 μm were tested at 550 °C under dry and humidified H2 (3-50% H2O) conditions without TPB line change. At 700 °C, and for 0.8 μm thick patterns, the TPB length showed pronounced change in H2 with 10-50% H2O. Significant increase in TPB length due to holes formation was observed at 800 °C with 3% and 10% H2O. Ni/YSZ pattern anodes with 1.0 μm thick Ni was stable in H2 with 3% H2O in the range 550-800 °C, with TPB line only slightly modified. However, distinct change of TPB line and Ni microstructure was observed with 10-70% H2O above 700 °C. Stabilization of the polarization resistance depends on temperature. To accelerate stabilization of the cell, pre-treatment of the cell in H2 with 3% H2O at 750 °C or 800 °C could be performed.

  2. 3D printed PLA-based scaffolds

    PubMed Central

    Serra, Tiziano; Mateos-Timoneda, Miguel A; Planell, Josep A; Navarro, Melba

    2013-01-01

    Rapid prototyping (RP), also known as additive manufacturing (AM), has been well received and adopted in the biomedical field. The capacity of this family of techniques to fabricate customized 3D structures with complex geometries and excellent reproducibility has revolutionized implantology and regenerative medicine. In particular, nozzle-based systems allow the fabrication of high-resolution polylactic acid (PLA) structures that are of interest in regenerative medicine. These 3D structures find interesting applications in the regenerative medicine field where promising applications including biodegradable templates for tissue regeneration purposes, 3D in vitro platforms for studying cell response to different scaffolds conditions and for drug screening are considered among others. Scaffolds functionality depends not only on the fabrication technique, but also on the material used to build the 3D structure, the geometry and inner architecture of the structure, and the final surface properties. All being crucial parameters affecting scaffolds success. This Commentary emphasizes the importance of these parameters in scaffolds’ fabrication and also draws the attention toward the versatility of these PLA scaffolds as a potential tool in regenerative medicine and other medical fields. PMID:23959206

  3. 3D printed microfluidics for biological applications.

    PubMed

    Ho, Chee Meng Benjamin; Ng, Sum Huan; Li, King Ho Holden; Yoon, Yong-Jin

    2015-01-01

    The term "Lab-on-a-Chip," is synonymous with describing microfluidic devices with biomedical applications. Even though microfluidics have been developing rapidly over the past decade, the uptake rate in biological research has been slow. This could be due to the tedious process of fabricating a chip and the absence of a "killer application" that would outperform existing traditional methods. In recent years, three dimensional (3D) printing has been drawing much interest from the research community. It has the ability to make complex structures with high resolution. Moreover, the fast building time and ease of learning has simplified the fabrication process of microfluidic devices to a single step. This could possibly aid the field of microfluidics in finding its "killer application" that will lead to its acceptance by researchers, especially in the biomedical field. In this paper, a review is carried out of how 3D printing helps to improve the fabrication of microfluidic devices, the 3D printing technologies currently used for fabrication and the future of 3D printing in the field of microfluidics. PMID:26237523

  4. Fast and safe microwave-assisted glass channel-shaped microstructure fabrication.

    PubMed

    Zacheo, A; Zizzari, A; Perrone, E; Carbone, L; Giancane, G; Valli, L; Rinaldi, R; Arima, V

    2015-06-01

    Glass micromachining is a basic technology to achieve microfluidic networks for lab-on-a-chip applications. Among several methods to microstructure glass, the simplest and most widely applied is wet chemical etching (WE). However, accurate control of the reaction conditions to perform reproducible, fast and safe glass etching is not straightforward. Herein, microwave-assisted WE is demonstrated to intensify the glass etching action under safe working and finely monitored operative conditions and to produce smooth deep channels in short processing times with reduced underetching effects. PMID:25920905

  5. Pressureless sintered beta prime-Si3N4 solid solution: Fabrication, microstructure, and strength

    NASA Technical Reports Server (NTRS)

    Dutta, S.

    1977-01-01

    Si3N4, AlN, and Al2O3 were used as basic constituents in a study of the pressureless sintering of beta prime-Si3N4 solid solution as a function of temperature. Y2O3-SiO2 additions were used to promote liquid-phase sintering. The sintered specimens were characterized with respect to density, microstructure, strength, oxidation, and thermal shock resistance. Density greater than 98 percent of theoretical was achieved by pressureless sintering at 1750 C. The microstructure consisted essentially of fine-grained beta prime-Si3N4 solid solution as the major phase. Modulus of rupture strengths up to 483 MPa were achieved at moderate temperature (1000 C), but decreased to 228 MPa at 1380 C. This substantial strength loss was attributed to a glassy grain boundary phase formed during cooling from the sintering temperature. The best oxidation resistance was exhibited by a composition containing 3 mol % Y2O3-SiO2 additives. Water quench thermal shock resistance was equivalent to that of reaction sintered silicon nitride but lower than hot-pressed silicon nitride.

  6. Pressureless sintered beta-prime-Si3N4 solid solution - Fabrication, microstructure, and strength

    NASA Technical Reports Server (NTRS)

    Dutta, S.

    1977-01-01

    Pressureless sintering of beta-prime-Si3N4 solid solution was studied as a function of temperature using Si3N4, A1N, and Al2O3 as basic constituents. Y2O3-SiO2 additions were used to promote liquid-phase sintering. The sintered specimens were characterized with respect to density, microstructure, strength, oxidation, and thermal shock resistance. Density greater than 98 percent of theoretical was achieved by pressureless sintering at 1750 C. The microstructure consisted essentially of fine-grained beta-prime-Si3N4 solid solution as the major phase. Modulus of rupture strengths up to 483 M Pa were achieved at moderate temperature (1000 C), but decreased to 228 M Pa at 1380 C. This substantial strength loss was attributed to a 'glassy' grain boundary phase formed during cooling from the sintering temperature. The best oxidation resistance was exhibited by a composition containing 3 mol % Y2O3-SiO2 additives. Water quench thermal shock resistance was equivalent to that of reaction sintered silicon nitride but lower than hot-pressed silicon nitride.

  7. Interfacial Microstructure Evolution and Shear Strength of Titanium Sandwich Structures Fabricated by Brazing

    NASA Astrophysics Data System (ADS)

    Wang, Wentao; Fan, Minyu; Li, Jinlong; Tao, Jie

    2016-03-01

    The corrugated sandwich structure, consisting of a CP Ti (commercially pure titanium) core between two Ti-6Al-4V face sheets, was brazed using pasty Ti-37.5Zr-15Cu-10Ni as filler alloy, at the temperature of 870°C for 5, 10, 20, and 30 min. The effect of brazing time on the microstructure and elemental distribution of the brazed joints was examined by means of SEM, EDS, and XRD analyses. It was found that various intermetallic phases were formed in the brazed joints, following a brazing time of 5 min, and their contents were decreased by the increment of brazing time, while prolonged brazing time resulted in a fine, acicular Widmanstätten microstructure throughout the entire joint. In addition, shear testing was performed in the brazed corrugated specimens in order to indirectly assess the quality of the joints. The debonding between CP Ti and Ti-6Al-4V was observed in the specimen brazed for 5 min and the fracture of the CP Ti corrugated core occurred after 30 min of brazing time. Additionally, when brazed for 10 min or 20 min, brittle intermetallic compounds in the joints and the grain growth of the base metal were controllable. Therefore, the sandwich structures failed without debonding in the joints or fracture within the base metal, demonstrating a good combination of strength and ductility.

  8. Multiviewer 3D monitor

    NASA Astrophysics Data System (ADS)

    Kostrzewski, Andrew A.; Aye, Tin M.; Kim, Dai Hyun; Esterkin, Vladimir; Savant, Gajendra D.

    1998-09-01

    Physical Optics Corporation has developed an advanced 3-D virtual reality system for use with simulation tools for training technical and military personnel. This system avoids such drawbacks of other virtual reality (VR) systems as eye fatigue, headaches, and alignment for each viewer, all of which are due to the need to wear special VR goggles. The new system is based on direct viewing of an interactive environment. This innovative holographic multiplexed screen technology makes it unnecessary for the viewer to wear special goggles.

  9. 3D Audio System

    NASA Technical Reports Server (NTRS)

    1992-01-01

    Ames Research Center research into virtual reality led to the development of the Convolvotron, a high speed digital audio processing system that delivers three-dimensional sound over headphones. It consists of a two-card set designed for use with a personal computer. The Convolvotron's primary application is presentation of 3D audio signals over headphones. Four independent sound sources are filtered with large time-varying filters that compensate for motion. The perceived location of the sound remains constant. Possible applications are in air traffic control towers or airplane cockpits, hearing and perception research and virtual reality development.

  10. Medical 3D Printing for the Radiologist.

    PubMed

    Mitsouras, Dimitris; Liacouras, Peter; Imanzadeh, Amir; Giannopoulos, Andreas A; Cai, Tianrun; Kumamaru, Kanako K; George, Elizabeth; Wake, Nicole; Caterson, Edward J; Pomahac, Bohdan; Ho, Vincent B; Grant, Gerald T; Rybicki, Frank J

    2015-01-01

    While use of advanced visualization in radiology is instrumental in diagnosis and communication with referring clinicians, there is an unmet need to render Digital Imaging and Communications in Medicine (DICOM) images as three-dimensional (3D) printed models capable of providing both tactile feedback and tangible depth information about anatomic and pathologic states. Three-dimensional printed models, already entrenched in the nonmedical sciences, are rapidly being embraced in medicine as well as in the lay community. Incorporating 3D printing from images generated and interpreted by radiologists presents particular challenges, including training, materials and equipment, and guidelines. The overall costs of a 3D printing laboratory must be balanced by the clinical benefits. It is expected that the number of 3D-printed models generated from DICOM images for planning interventions and fabricating implants will grow exponentially. Radiologists should at a minimum be familiar with 3D printing as it relates to their field, including types of 3D printing technologies and materials used to create 3D-printed anatomic models, published applications of models to date, and clinical benefits in radiology. Online supplemental material is available for this article. PMID:26562233

  11. Three-dimensional particle tracking around microstructures in water via total internal reflection fluorescence microscopy and refractive-index-matching method

    NASA Astrophysics Data System (ADS)

    Unno, Noriyuki; Nakata, Shuichiro; Satake, Shin-ichi; Taniguchi, Jun

    2016-07-01

    Multilayer nanoparticle image velocimetry (MnPIV) with a refractive-index-matching method is powerful technique for x- y- z (3D) flow measurement, because it can detect the 3D position of fluorescent particles with submicron resolution. In MnPIV, the intensity of fluorescence of a particle is used to estimate its z-position. However, it has been difficult to measure 3D flows around microstructures in water by total internal reflection fluorescence microscopy because of light scattering caused by the different refractive indices of the structures and the working fluid. By using a thermal nanoimprinting technique, we succeeded in fabricating microstructures from a polymer resin whose refractive index is equal to that of water, and we used these microstructures to perform MnPIV in water. As a result of the match between the refractive index of water and that of the microstructures, we were able to perform 3D tracking of nanoparticles around the microstructures in water.

  12. Microstructure and Properties of DCP-Derived W-ZrC Composite Using Nontoxic Sodium Alginate to Fabricate WC Preform

    NASA Astrophysics Data System (ADS)

    Najafzadeh Khoee, Ali Asghar; Habibolahzadeh, Ali; Qods, Fathallah; Baharvandi, Hamidreza

    2015-04-01

    In the present work, tungsten carbide (WC) preforms were fabricated by gel-casting process, using different nontoxic Na-alginate to tertiary calcium phosphate ratios and different loadings of WC powder in the initial slurries. The gel-cast green bodies were dried and pre-sintered at 1723 K for 4 h and then reactively infiltrated by molten Zr2Cu at 1623 K for 0.5 h, to produce W-ZrC composite via displacive compensation of porosity process. The phases, microstructures, and mechanical properties of the preforms and the W-ZrC composites were investigated by Fourier transform infrared spectroscope, x-ray diffractometer (XRD), scanning electron microscope (SEM), image analyzer, and universal mechanical testing machine. XRD results, SEM micrographs, and elemental maps indicated uniform distribution of phases (W and ZrC) and elements (W, Zr, and C). Flexural strengths and hardness of the fabricated composites were in the ranges of 429-460 MPa and 7.5-9.5 GPa, respectively. Fractography studies revealed two types of dimple rupture and cleavage fracture modes in different composite samples. The W-ZrC composite was ablated by an oxyacetylene flame for 60 s. The mean value of mass and linear ablation rates of the composite were 2.1 ± 0.1 mg/s and 3.6 ± 0.5 µm/s, respectively.

  13. 3D Surgical Simulation

    PubMed Central

    Cevidanes, Lucia; Tucker, Scott; Styner, Martin; Kim, Hyungmin; Chapuis, Jonas; Reyes, Mauricio; Proffit, William; Turvey, Timothy; Jaskolka, Michael

    2009-01-01

    This paper discusses the development of methods for computer-aided jaw surgery. Computer-aided jaw surgery allows us to incorporate the high level of precision necessary for transferring virtual plans into the operating room. We also present a complete computer-aided surgery (CAS) system developed in close collaboration with surgeons. Surgery planning and simulation include construction of 3D surface models from Cone-beam CT (CBCT), dynamic cephalometry, semi-automatic mirroring, interactive cutting of bone and bony segment repositioning. A virtual setup can be used to manufacture positioning splints for intra-operative guidance. The system provides further intra-operative assistance with the help of a computer display showing jaw positions and 3D positioning guides updated in real-time during the surgical procedure. The CAS system aids in dealing with complex cases with benefits for the patient, with surgical practice, and for orthodontic finishing. Advanced software tools for diagnosis and treatment planning allow preparation of detailed operative plans, osteotomy repositioning, bone reconstructions, surgical resident training and assessing the difficulties of the surgical procedures prior to the surgery. CAS has the potential to make the elaboration of the surgical plan a more flexible process, increase the level of detail and accuracy of the plan, yield higher operative precision and control, and enhance documentation of cases. Supported by NIDCR DE017727, and DE018962 PMID:20816308

  14. Fabrication and microstructure characterization of inert matrix fuel based on yttria stabilized zirconia

    NASA Astrophysics Data System (ADS)

    Hellwig, Ch.; Pouchon, M.; Restani, R.; Ingold, F.; Bart, G.

    2005-04-01

    The deployment of a suitable, Pu-bearing inert matrix fuel (IMF) could offer an attractive option as a single-recycling LWR strategy aimed at reducing the currently growing plutonium stockpiles. A development programme focusing on yttria stabilized zirconia (YSZ)-based IMF is conducted at PSI. YSZ-based IMF has so far been irradiated in two test reactors. The fabrication routes as well as the characterization of the irradiated material by ceramography, electronprobe microanalysis, and X-ray diffraction are presented. IMF fabrication by attrition milling of the oxide constituents is possible, but high sintering temperatures are required to achieve homogeneity. X-ray diffraction is a suitable tool to monitor the homogeneity. Extra efforts are needed to increase the density.

  15. Micro-structured polymer scaffolds fabricated by direct laser writing for tissue engineering

    NASA Astrophysics Data System (ADS)

    Danilevicius, Paulius; Rekstyte, Sima; Balciunas, Evaldas; Kraniauskas, Antanas; Jarasiene, Rasa; Sirmenis, Raimondas; Baltriukiene, Daiva; Bukelskiene, Virginija; Gadonas, Roaldas; Malinauskas, Mangirdas

    2012-08-01

    This work presents the latest results on direct laser writing of polymeric materials for tissue engineering applications. A femtosecond Yb:KGW laser (300 fs, 200 kHz, 515 nm) was used as a light source for non-linear lithography. Fabrication was implemented in various photosensitive polymeric materials, such as: hybrid organic-inorganic sol-gel based on silicon-zirconium oxides, commercial ORMOCER class photoresins. These materials were structured via multi-photon polymerization technique with submicron resolution. Porous three-dimensional scaffolds for artificial tissue engineering were fabricated with constructed system and were up to several millimeters in overall size with 10 to 100 μm internal pores. Biocompatibility of the used materials was tested in primary rabbit muscle-derived stem cell culture in vitro and using laboratory rats in vivo. This interdisciplinary study suggests that proposed technique and materials are suitable for tissue engineering applications.

  16. Controlled double emulsification utilizing 3D PDMS microchannels

    NASA Astrophysics Data System (ADS)

    Chang, Fu-Che; Su, Yu-Chuan

    2008-06-01

    This paper presents a PDMS emulsification device that is capable of generating water-in-oil-in-water double emulsions in a controlled manner. Specially designed 3D microchannels are utilized to steer the independently driven water- and oil-phase flows (especially to restrict the attachment of the middle oil-phase flow on the channel surfaces), and to break the continuous flows into monodisperse double emulsions. In addition to channel geometries and fluid flow rates, surfactants and osmotic agents are employed to facilitate the breakup process and stabilize the resulting emulsion structures. In the prototype demonstration, two-level SU-8 molds were fabricated to duplicate PDMS microstructures, which were surface treated and bonded irreversibly to form 3D microchannels. Throughout the emulsification trials, dripping was intentionally induced to generate monodisperse double emulsions with single or multiple aqueous droplets inside each oil drop. It is found that the overall and core sizes of the resulting double emulsions could be adjusted independently, mainly by varying the outer and inner fluid flow rates, respectively. As such, the presented double emulsification device could potentially realize the controllability on emulsion structure and size distribution, which is desired for a variety of biological and pharmaceutical applications.

  17. Interfacial Microstructure and Bonding Strength of Copper Cladding Aluminum Rods Fabricated by Horizontal Core-Filling Continuous Casting

    NASA Astrophysics Data System (ADS)

    Su, Ya-Jun; Liu, Xin-Hua; Huang, Hai-You; Liu, Xue-Feng; Xie, Jian-Xin

    2011-12-01

    Copper cladding aluminum (CCA) rods with a diameter of 30 mm and a sheath thickness of 3 mm were fabricated by horizontal core-filling continuous casting (HCFC) technology. The microstructure and morphology, distribution of chemical components, and phase composition of the interface between Cu and Al were characterized by scanning electron microscope (SEM), transmission electron microscope (TEM), and energy dispersive spectrometer (EDS). The formation mechanism of the interface and the effects of key processing parameters, e.g., aluminum casting temperature, secondary cooling intensity, and mean withdrawing speed on the interfacial microstructure and bonding strength were investigated. The results show that the CCA rod has a multilayered interface, which is composed of three sublayers—sublayer I is Cu9Al4 layer, sublayer II is CuAl2 layer, and sublayer III is composed of α-Al/CuAl2 pseudo eutectic. The thickness of sublayer III, which occupies 92 to 99 pct of the total thickness of the interface, is much larger than the thicknesses of sublayers I and II. However, the interfacial bonding strength is dominated by the thicknesses of sublayers I and II; i.e., the bonding strength decreases with the rise of the thicknesses of sublayers I and II. When raising the aluminum casting temperature, the total thickness of the interface increases while the thicknesses of sublayers I and II decrease and the bonding strength increases. Either augmenting the secondary cooling intensity or increasing the mean withdrawing speed results in the decrease in both total thickness of the interface and the thicknesses of sublayers I and II, and an increase in the interfacial bonding strength. The CCA rod with the largest interfacial bonding strength of 67.9 ± 0.5 MPa was fabricated under such processing parameters as copper casting temperature 1503 K (1230 °C), aluminum casting temperature 1063 K (790 °C), primary cooling water flux 600 L/h, secondary cooling water flux 700 L/h, and

  18. Mechanical and microstructural characterization of Al7075/SiC nanocomposites fabricated by dynamic compaction

    NASA Astrophysics Data System (ADS)

    Atrian, A.; Majzoobi, G. H.; Enayati, M. H.; Bakhtiari, H.

    2014-03-01

    This paper describes the synthesis of Al7075 metal matrix composites reinforced with SiC, and the characterization of their microstructure and mechanical behavior. The mechanically milled Al7075 micron-sized powder and SiC nanoparticles are dynamically compacted using a drop hammer device. This compaction is performed at different temperatures and for various volume fractions of SiC nanoparticles. The relative density is directly related to the compaction temperature rise and indirectly related to the content of SiC nanoparticle reinforcement, respectively. Furthermore, increasing the amount of SiC nanoparticles improves the strength, stiffness, and hardness of the compacted specimens. The increase in hardness and strength may be attributed to the inherent hardness of the nanoparticles, and other phenomena such as thermal mismatch and crack shielding. Nevertheless, clustering of the nanoparticles at aluminum particle boundaries make these regions become a source of concentrated stress, which reduces the load carrying capacity of the compacted nanocomposite.

  19. Factors affecting the microstructural stability and durability of thermal barrier coatings fabricated by air plasma spraying

    SciTech Connect

    Helminiak, M A; Yanar, N M; Pettit, F S; Taylor, T A; Meier, G H

    2012-10-01

    The high-temperature behavior of high-purity, low-density (HP-LD) air plasma sprayed (APS) thermal barrier coatings (TBCs) with NiCoCrAlY bond coats deposited by argon-shrouded plasma spraying is described. The high purity yttria-stabilized zirconia resulted in top coats which are highly resistant to sintering and transformation from the metastable tetragonal phase to the equilibrium mixture of monoclinic and cubic phases. The thermal conductivity of the as-processed TBC is low but increases during high temperature exposure even before densification occurs. The porous topcoat microstructure also resulted in good spallation resistance during thermal cycling. The actual failure mechanisms of the APS coatings were found to depend on topcoat thickness, topcoat density, and the thermal cycle frequency. The failure mechanisms are described and the durability of the HP-LD coatings is compared with that of state-of-the-art electron beam physical vapor deposition TBCs.

  20. 3D polarimetric purity

    NASA Astrophysics Data System (ADS)

    Gil, José J.; San José, Ignacio

    2010-11-01

    From our previous definition of the indices of polarimetric purity for 3D light beams [J.J. Gil, J.M. Correas, P.A. Melero and C. Ferreira, Monogr. Semin. Mat. G. de Galdeano 31, 161 (2004)], an analysis of their geometric and physical interpretation is presented. It is found that, in agreement with previous results, the first parameter is a measure of the degree of polarization, whereas the second parameter (called the degree of directionality) is a measure of the mean angular aperture of the direction of propagation of the corresponding light beam. This pair of invariant, non-dimensional, indices of polarimetric purity contains complete information about the polarimetric purity of a light beam. The overall degree of polarimetric purity is obtained as a weighted quadratic average of the degree of polarization and the degree of directionality.

  1. 3D field harmonics

    SciTech Connect

    Caspi, S.; Helm, M.; Laslett, L.J.

    1991-03-30

    We have developed an harmonic representation for the three dimensional field components within the windings of accelerator magnets. The form by which the field is presented is suitable for interfacing with other codes that make use of the 3D field components (particle tracking and stability). The field components can be calculated with high precision and reduced cup time at any location (r,{theta},z) inside the magnet bore. The same conductor geometry which is used to simulate line currents is also used in CAD with modifications more readily available. It is our hope that the format used here for magnetic fields can be used not only as a means of delivering fields but also as a way by which beam dynamics can suggest correction to the conductor geometry. 5 refs., 70 figs.

  2. 'Bonneville' in 3-D!

    NASA Technical Reports Server (NTRS)

    2004-01-01

    The Mars Exploration Rover Spirit took this 3-D navigation camera mosaic of the crater called 'Bonneville' after driving approximately 13 meters (42.7 feet) to get a better vantage point. Spirit's current position is close enough to the edge to see the interior of the crater, but high enough and far enough back to get a view of all of the walls. Because scientists and rover controllers are so pleased with this location, they will stay here for at least two more martian days, or sols, to take high resolution panoramic camera images of 'Bonneville' in its entirety. Just above the far crater rim, on the left side, is the rover's heatshield, which is visible as a tiny reflective speck.

  3. 3D bioprinting for engineering complex tissues.

    PubMed

    Mandrycky, Christian; Wang, Zongjie; Kim, Keekyoung; Kim, Deok-Ho

    2016-01-01

    Bioprinting is a 3D fabrication technology used to precisely dispense cell-laden biomaterials for the construction of complex 3D functional living tissues or artificial organs. While still in its early stages, bioprinting strategies have demonstrated their potential use in regenerative medicine to generate a variety of transplantable tissues, including skin, cartilage, and bone. However, current bioprinting approaches still have technical challenges in terms of high-resolution cell deposition, controlled cell distributions, vascularization, and innervation within complex 3D tissues. While no one-size-fits-all approach to bioprinting has emerged, it remains an on-demand, versatile fabrication technique that may address the growing organ shortage as well as provide a high-throughput method for cell patterning at the micrometer scale for broad biomedical engineering applications. In this review, we introduce the basic principles, materials, integration strategies and applications of bioprinting. We also discuss the recent developments, current challenges and future prospects of 3D bioprinting for engineering complex tissues. Combined with recent advances in human pluripotent stem cell technologies, 3D-bioprinted tissue models could serve as an enabling platform for high-throughput predictive drug screening and more effective regenerative therapies. PMID:26724184

  4. Femtosecond laser microstructuring for polymeric lab-on-chips.

    PubMed

    Eaton, Shane M; De Marco, Carmela; Martinez-Vazquez, Rebeca; Ramponi, Roberta; Turri, Stefano; Cerullo, Giulio; Osellame, Roberto

    2012-08-01

    This paper provides an overview of femtosecond laser microfabrication in polymeric materials, with emphasis on lab-on-chip applications. Due to the nonlinear interaction of femtosecond laser pulses with polymers, laser-induced modifications are localized to the focal volume, enabling high resolution patterning in 3D. Femtosecond laser microfabrication offers unmatched versatility in fabricating surface microchannels and diffractive optics by means of laser ablation, buried optical waveguides and micro-optics through refractive index modification and complex 3D microstructures in photoresists by two-photon polymerization. Femtosecond laser microfabrication technology opens the door to fabricating integrated lab-on-chip devices with a single tool. PMID:22589025

  5. Fabrication methods and applications of microstructured gallium based liquid metal alloys

    NASA Astrophysics Data System (ADS)

    Khondoker, M. A. H.; Sameoto, D.

    2016-09-01

    This review contains a comparative study of reported fabrication techniques of gallium based liquid metal alloys embedded in elastomers such as polydimethylsiloxane or other rubbers as well as the primary challenges associated with their use. The eutectic gallium–indium binary alloy (EGaIn) and gallium–indium–tin ternary alloy (galinstan) are the most common non-toxic liquid metals in use today. Due to their deformability, non-toxicity and superior electrical conductivity, these alloys have become very popular among researchers for flexible and reconfigurable electronics applications. All the available manufacturing techniques have been grouped into four major classes. Among them, casting by needle injection is the most widely used technique as it is capable of producing features as small as 150 nm width by high-pressure infiltration. One particular fabrication challenge with gallium based liquid metals is that an oxide skin is rapidly formed on the entire exposed surface. This oxide skin increases wettability on many surfaces, which is excellent for keeping patterned metal in position, but is a drawback in applications like reconfigurable circuits, where the position of liquid metal needs to be altered and controlled accurately. The major challenges involved in many applications of liquid metal alloys have also been discussed thoroughly in this article.

  6. Microstructure and tensile properties of iron parts fabricated by selective laser melting

    NASA Astrophysics Data System (ADS)

    Song, Bo; Dong, Shujuan; Deng, Sihao; Liao, Hanlin; Coddet, Christian

    2014-03-01

    Iron, as the basic industry material was extensively studied in the past, but it could still offer extended possibilities with the use of new processing techniques such as selective laser melting (SLM). In this work, the manufacturing of iron parts using SLM technology was investigated. The effect of processing parameters on density of the iron parts was studied. Fully dense iron parts have been fabricated at the laser power of 100 W using different laser scanning speeds. By means of metallographic observation and TEM characterization, it can be found that the grains size decreased with increasing scanning speed and high dislocation density was observed. Tensile specimens were fabricated using optimal parameters and mechanical tests allowed observing an ultimate tensile strength of 412 MPa and the yield strength of 305 MPa. Multiple self-strengthening mechanisms during SLM process are proposed to explain this high mechanical strength. The grain refinement seems to be the most significant strengthening mechanism, followed by work hardening arising from the high cooling rate.

  7. Mechanical Properties and Microstructure of Biomorphic Silicon Carbide Ceramics Fabricated from Wood Precursors

    NASA Technical Reports Server (NTRS)

    Singh, Mrityunjay; Salem, J. A.; Gray, Hugh R. (Technical Monitor)

    2002-01-01

    Silicon carbide based, environment friendly, biomorphic ceramics have been fabricated by the pyrolysis and infiltration of natural wood (maple and mahogany) precursors. This technology provides an eco-friendly route to advanced ceramic materials. These biomorphic silicon carbide ceramics have tailorable properties and behave like silicon carbide based materials manufactured by conventional approaches. The elastic moduli and fracture toughness of biomorphic ceramics strongly depend on the properties of starting wood preforms and the degree of molten silicon infiltration. Mechanical properties of silicon carbide ceramics fabricated from maple wood precursors indicate the flexural strengths of 3441+/-58 MPa at room temperature and 230136 MPa at 1350C. Room temperature fracture toughness of the maple based material is 2.6 +/- 0.2 MPa(square root of)m while the mahogany precursor derived ceramics show a fracture toughness of 2.0 +/- 0.2 Mpa(square root of)m. The fracture toughness and the strength increase as the density of final material increases. Fractographic characterization indicates the failure origins to be pores and chipped pockets of silicon.

  8. Development of cylindrical reactive ion etching technology for fabricating tubular microstructures

    NASA Astrophysics Data System (ADS)

    Matsui, Tomoki; Takeuchi, Yugo; Shirao, Akitoshi; Nakashima, Yuta; Sato, Katsuya; Minami, Kazuyuki

    2014-05-01

    This paper describes the development of a novel technology that can form a dense and complex pattern on a polymer tube without thermal damage. We have developed an etching mask and equipment capable of processing the tubular material. We named this technology cylindrical RIE (reactive ion etching). In order to evaluate the fundamental processing characteristics of this technology, etching rate, side etching ratio and etching uniformities along the tube axis and circumferential directions are evaluated. As a result, a vertical wall caused by anisotropic etching could be observed, and the average etching rate was 1.0 µm min-1 and the average side etching ratio was 0.027. The maximum differences between etching rate along the axis and circumferential directions were 0.25 and 0.12 µm min-1, respectively. The cross-section of the etched through-groove (slit) processed in a PP (polypropylene) tube having wall thickness of 200 µm was evaluated. By the bowing phenomenon, pattern width decreased most at the middle of the thickness of the tube wall, and average width errors at the middle of the thickness was 22.4 µm. To demonstrate the usefulness of the cylindrical RIE, a stent made of PP tube was fabricated. It was possible to fabricate a stent with an outer diameter of 4.4 mm, length of 19 mm, main strut width of 300 µm, and connecting strut width of 80 µm.

  9. Microstructural Characterization of Bonding Interfaces in Aluminum 3003 Blocks Fabricated by Ultrasonic Additive Manufacturing

    SciTech Connect

    Schick, D. E.; Babu, Sudarsanam Suresh; Lippold, John C; Hahnlen, R.M.; Dapino, M.J.; Dehoff, Ryan R; Collins, P.

    2010-01-01

    Ultrasonic additive manufacturing (UAM) is a process by which hybrid and near-netshaped products can be manufactured from thin metallic tapes. One of the main concerns of UAM is the development of anisotropic mechanical properties. In this work, the microstructures in the bond regions are characterized with optical and electron microscopy. Recrystallization and grain growth across the interface are proposed as a mechanism for the bond formation. The presence of voids or unbonded areas, which reduce the load-bearing cross section and create a stress intensity factor, is attributed to the transfer of the sonotrode texture to the new foil layer. This results in large peaks and valleys that are not filled in during processing. Tensile testing revealed the weld interface strength was 15% of the bulk foil. Shear tests of the weld interfaces showed almost 50% of the bulk shear strength of the material. Finally, optical microscopy of the fracture surfaces from the tensile tests revealed 34% of the interface area was unbonded.

  10. Microstructure and Electrochemical Behavior of Fe-Based Amorphous Metallic Coatings Fabricated by Atmospheric Plasma Spraying

    NASA Astrophysics Data System (ADS)

    Zhou, Z.; Wang, L.; He, D. Y.; Wang, F. C.; Liu, Y. B.

    2011-01-01

    A Fe48Cr15Mo14C15B6Y2 alloy with high glass forming ability (GFA) was selected to prepare amorphous metallic coatings by atmospheric plasma spraying (APS). The as-deposited coatings present a dense layered structure and low porosity. Microstructural studies show that some nanocrystals and a fraction of yttrium oxides formed during spraying, which induced the amorphous fraction of the coatings decreasing to 69% compared with amorphous alloy ribbons of the same component. High thermal stability enables the amorphous coatings to work below 910 K without crystallization. The results of electrochemical measurement show that the coatings exhibit extremely wide passive region and relatively low passive current density in 3.5% NaCl and 1 mol/L HCl solutions, which illustrate their superior ability to resist localized corrosion. Moreover, the corrosion behavior of the amorphous coatings in 1 mol/L H2SO4 solution is similar to their performance under conditions containing chloride ions, which manifests their flexible and extensive ability to withstand aggressive environments.

  11. 3D Micropatterned Surface Inspired by Salvinia molesta via Direct Laser Lithography

    PubMed Central

    2015-01-01

    Biomimetic functional surfaces are attracting increasing attention for their relevant technological applications. Despite these efforts, inherent limitations of microfabrication techniques prevent the replication of complex hierarchical microstructures. Using a 3D laser lithography technique, we fabricated a 3D patterned surface bioinspired to Salvinia molesta leaves. The artificial hairs, with crownlike heads, were reproduced by scaling down (ca. 100 times smaller) the dimensions of natural features, so that microscale hairs with submicrometric resolution were attained. The micropatterned surface, in analogy with the natural model, shows interesting properties in terms of hydrophobicity and air retention when submerged by water, even if realized with a hydrophilic material. Furthermore, we successfully demonstrated the capability to promote localized condensation of water droplets from moisture in the atmosphere. PMID:26558410

  12. Effect of holding temperature on microstructures and Jc properties of YBa2Cu3O7-X films fabricated by TFA-MOD method

    NASA Astrophysics Data System (ADS)

    Konya, K.; Ootaguro, K.; Nishiyama, T.; Teranishi, R.; Kiss, T.; Yamada, K.; Kaneko, K.; Yoshizumi, M.; Izumi, T.

    2013-11-01

    In this study, we investigated the correlation between microstructures and critical current density (Jc) of YBa2Cu3O7-X (YBCO) films with BaZrO3 (BZO) pinning centers by introducing holding temperature during the crystallization process. Smaller BZO particles and higher in-field Jc were found in the YBCO film with holding temperature than the one without. As a result, films with improved microstructures were successfully fabricated by implementation of additional process, holding temperature, and highly in-field Jc were obtained by introducing smaller BZO particles as artificial pinning centers.

  13. DNA Assembly in 3D Printed Fluidics.

    PubMed

    Patrick, William G; Nielsen, Alec A K; Keating, Steven J; Levy, Taylor J; Wang, Che-Wei; Rivera, Jaime J; Mondragón-Palomino, Octavio; Carr, Peter A; Voigt, Christopher A; Oxman, Neri; Kong, David S

    2015-01-01

    The process of connecting genetic parts-DNA assembly-is a foundational technology for synthetic biology. Microfluidics present an attractive solution for minimizing use of costly reagents, enabling multiplexed reactions, and automating protocols by integrating multiple protocol steps. However, microfluidics fabrication and operation can be expensive and requires expertise, limiting access to the technology. With advances in commodity digital fabrication tools, it is now possible to directly print fluidic devices and supporting hardware. 3D printed micro- and millifluidic devices are inexpensive, easy to make and quick to produce. We demonstrate Golden Gate DNA assembly in 3D-printed fluidics with reaction volumes as small as 490 nL, channel widths as fine as 220 microns, and per unit part costs ranging from $0.61 to $5.71. A 3D-printed syringe pump with an accompanying programmable software interface was designed and fabricated to operate the devices. Quick turnaround and inexpensive materials allowed for rapid exploration of device parameters, demonstrating a manufacturing paradigm for designing and fabricating hardware for synthetic biology. PMID:26716448

  14. DNA Assembly in 3D Printed Fluidics

    PubMed Central

    Patrick, William G.; Nielsen, Alec A. K.; Keating, Steven J.; Levy, Taylor J.; Wang, Che-Wei; Rivera, Jaime J.; Mondragón-Palomino, Octavio; Carr, Peter A.; Voigt, Christopher A.; Oxman, Neri; Kong, David S.

    2015-01-01

    The process of connecting genetic parts—DNA assembly—is a foundational technology for synthetic biology. Microfluidics present an attractive solution for minimizing use of costly reagents, enabling multiplexed reactions, and automating protocols by integrating multiple protocol steps. However, microfluidics fabrication and operation can be expensive and requires expertise, limiting access to the technology. With advances in commodity digital fabrication tools, it is now possible to directly print fluidic devices and supporting hardware. 3D printed micro- and millifluidic devices are inexpensive, easy to make and quick to produce. We demonstrate Golden Gate DNA assembly in 3D-printed fluidics with reaction volumes as small as 490 nL, channel widths as fine as 220 microns, and per unit part costs ranging from $0.61 to $5.71. A 3D-printed syringe pump with an accompanying programmable software interface was designed and fabricated to operate the devices. Quick turnaround and inexpensive materials allowed for rapid exploration of device parameters, demonstrating a manufacturing paradigm for designing and fabricating hardware for synthetic biology. PMID:26716448

  15. Effect of PEG additive on anode microstructure and cell performance of anode-supported MT-SOFCs fabricated by phase inversion method

    NASA Astrophysics Data System (ADS)

    Ren, Cong; Liu, Tong; Maturavongsadit, Panita; Luckanagul, Jittima Amie; Chen, Fanglin

    2015-04-01

    Anode-supported micro-tubular solid oxide fuel cells (MT-SOFCs) have been fabricated by phase inversion method. For the anode support preparation, N-methyl-2-pyrrolidone (NMP), polyethersulfone (PESf) and poly ethylene glycol (PEG) were applied as solvent, polymer binder and additive, respectively. The effect of molecular weight and amount of PEG additive on the thermodynamics of the casting solutions was characterized by measuring the coagulation value. Viscosity of the casting slurries was also measured and the influence of PEG additive on viscosity was studied and discussed. The presence of PEG in the casting slurry can significantly influence the final anode support microstructure. Based on the microstructure result and the measured gas permeation value, two anode supports were selected for cell fabrication. For cell with the anode support fabricated using slurry with PEG additive, a maximum cell power density of 704 mW cm-2 is obtained at 750 °C with humidified hydrogen as fuel and ambient air as oxidant; cell fabricated without any PEG additive shows the peak cell power density of 331 mW cm-2. The relationship between anode microstructure and cell performance was discussed.

  16. Proton Transport and Microstructure Properties in Superlattice Thin Films Fabricated by Pulsed Laser Deposition

    NASA Astrophysics Data System (ADS)

    Kuwata, Naoaki; Sata, Noriko; Tsurui, Takao; Yugami, Hiroo

    2005-12-01

    Superlattice thin films of the perovskite-type oxide proton conductor SrZr0.95Y0.05O3/SrTiO3 was fabricated by pulsed laser deposition. Their structural and proton transport properties were reported. X-ray diffraction analysis and selected area electron diffraction revealed that the thin films were epitaxially grown on MgO(001) substrate. High-density edge dislocations and a columnar structure were observed in the films by high-resolution electron microscopy. The in-plane electrical conductivity of the thin films was determined by impedance spectroscopy. The contribution of proton transport to the total conductivity of the films was confirmed by H2O/D2O exchange measurement. The conductivity of superlattice films was increased by introducing heterointerfaces. The high activation energy (Ea=1.0 eV) was explained by the grain-boundary effect of the columnar structure in the films.

  17. Optical and structural characterization of silicon microstructures fabricated by laser interference crystallization

    SciTech Connect

    Toet, D.; Aichmayr, G.; Mulato, M.; Santos, P.V.; Spangenberg, A.; Bergmann, R.B.

    1997-07-01

    Uniform gratings of sharply defined polycrystalline silicon lines with micrometer-sized periods were created by laser interference crystallization of amorphous silicon. Atomic force microscopy (AFM) reveals that lines fabricated with high pulse energies (380 mJ/cm{sup 2}) contain large grains (dimensions up to 1.5 {micro}m), growing in a direction perpendicular to the lines. The authors assign this strong lateral growth to the melting of the material in the center of the lines combined with the presence of small grains, which act as nuclei, at the interfaces with the amorphous regions. Spatially resolved Raman spectroscopy shows that size effects dominate the Raman line shape at the edge of the line, confirming the AFM results, while stress increases towards the center of the line. The spectra measured in the middle of lines created with high energies show doping effects caused by the diffusion of boron atoms from the substrate upon exposure.

  18. Electrodepositing fabrication and microstructures of the Fe nanowires with a preferred orientation

    NASA Astrophysics Data System (ADS)

    Cui, Chunxiang; Yang, Wei; Sun, Jibing; Zhang, Qingjun

    2011-12-01

    Highly ordered Fe nanowire arrays with <1 1 0> preferred orientation were fabricated out successfully by direct current electrodepositing into the pores of a porous anodic aluminum oxide template. The formation mechanism of Fe nanowires was ascertained by X-ray diffraction and transmission electron microscopy. Low index surface energy of Fe nanowires was calculated by means of broken-bond model. For Fe nanowire arrays, its aspect ratio ( h/ d) of the "circular cylinder" is less than 0.75, the {1 1 0} planes have the lowest surface energy. And authors deal with a reasonable explanation for Fe nanowires growth along with <1 1 0> preferred orientation using the two-dimensional nucleation theory.

  19. Printing 3D dielectric elastomer actuators for soft robotics

    NASA Astrophysics Data System (ADS)

    Rossiter, Jonathan; Walters, Peter; Stoimenov, Boyko

    2009-03-01

    We present a new approach to the fabrication of soft dielectric elastomer actuators using a 3D printing process. Complete actuators including active membranes and support structures can be 3D printed in one go, resulting in a great improvement in fabrication speed and increases in accuracy and consistency. We describe the fabrication process and present force and displacement results for a double-membrane antagonistic actuator. In this structure controlled prestrain is applied by the simple process of pressing together two printed actuator halves. The development of 3D printable soft actuators will have a large impact on many application areas including engineering, medicine and the emerging field of soft robotics.

  20. Prominent rocks - 3D

    NASA Technical Reports Server (NTRS)

    1997-01-01

    Many prominent rocks near the Sagan Memorial Station are featured in this image, taken in stereo by the Imager for Mars Pathfinder (IMP) on Sol 3. 3D glasses are necessary to identify surface detail. Wedge is at lower left; Shark, Half-Dome, and Pumpkin are at center. Flat Top, about four inches high, is at lower right. The horizon in the distance is one to two kilometers away.

    Mars Pathfinder is the second in NASA's Discovery program of low-cost spacecraft with highly focused science goals. The Jet Propulsion Laboratory, Pasadena, CA, developed and manages the Mars Pathfinder mission for NASA's Office of Space Science, Washington, D.C. JPL is an operating division of the California Institute of Technology (Caltech). The Imager for Mars Pathfinder (IMP) was developed by the University of Arizona Lunar and Planetary Laboratory under contract to JPL. Peter Smith is the Principal Investigator.

    Click below to see the left and right views individually. [figure removed for brevity, see original site] Left [figure removed for brevity, see original site] Right

  1. 'Diamond' in 3-D

    NASA Technical Reports Server (NTRS)

    2004-01-01

    This 3-D, microscopic imager mosaic of a target area on a rock called 'Diamond Jenness' was taken after NASA's Mars Exploration Rover Opportunity ground into the surface with its rock abrasion tool for a second time.

    Opportunity has bored nearly a dozen holes into the inner walls of 'Endurance Crater.' On sols 177 and 178 (July 23 and July 24, 2004), the rover worked double-duty on Diamond Jenness. Surface debris and the bumpy shape of the rock resulted in a shallow and irregular hole, only about 2 millimeters (0.08 inch) deep. The final depth was not enough to remove all the bumps and leave a neat hole with a smooth floor. This extremely shallow depression was then examined by the rover's alpha particle X-ray spectrometer.

    On Sol 178, Opportunity's 'robotic rodent' dined on Diamond Jenness once again, grinding almost an additional 5 millimeters (about 0.2 inch). The rover then applied its Moessbauer spectrometer to the deepened hole. This double dose of Diamond Jenness enabled the science team to examine the rock at varying layers. Results from those grindings are currently being analyzed.

    The image mosaic is about 6 centimeters (2.4 inches) across.

  2. Microstructural characterization of fiber-reinforced composites

    SciTech Connect

    Summerscales, J.

    1998-12-31

    In the past 50 years, great progress has been made in developing artificial fiber-reinforced composite materials, generally using filaments with microscopic diameters. An array of reinforcement forms can be used in commercial applications--with the microstructure being a critical factor in realizing the required properties in a material. This book comprehensively examines the application of advanced microstructural characterization techniques to fiber-reinforced composites. Its contents include: (1) flexible textile composite microstructure; (2) 3-D confocal microscopy of glass fiber-reinforced composites; (3) geometric modeling of yarn and fiber assemblies; (4) characterization of yarn shape in woven fabric composites; (5) quantitative microstructural analysis for continuous fiber composites; (6) electron microscopy of polymer composites; (7) micromechanics of reinforcement using laser raman spectroscopy; and (8) acoustic microscopy of ceramic fiber composites.

  3. Dynamically- and chemically-induced grain boundary migration in quartz: microstructures, crystallographic fabrics, and trace element contents

    NASA Astrophysics Data System (ADS)

    Nachlas, Will; Thomas, Jay

    2016-04-01

    Grain boundary migration (GBM) is a common mechanism by which quartz recrystallizes in the Earth. In the most basic sense, GBM occurs as atoms exchange structural positions across a planar defect. Reconstitution of grains via GBM imparts a new crystallographic orientation, but its effect on the geochemistry of recrystallized grains remains uncertain and depends on the kinetic and thermodynamic properties of the moving grain boundary. Two of the dominant driving forces for GBM are lattice strain energy, controlled by the applied stress field, and chemical potential energy, controlled by differences in mineral stability. We present observations from static and dynamic recrystallization experiments showing evidence for GBM in response to both of these driving forces. In static recrystallization experiments, quartz recrystallized in response to local variations in trace-level Ti concentrations, whereas in dynamic recrystallization experiments, quartz recrystallized during dislocation creep in response to the imposed differential stress. Each case produced recrystallized quartz exhibiting diagnostic microstructures, crystallographic fabrics, and trace element contents that can be used to infer the mechanisms of quartz recrystallization and the pressure-temperature conditions at which recrystallization occurred.

  4. Computer numerical control (CNC) lithography: light-motion synchronized UV-LED lithography for 3D microfabrication

    NASA Astrophysics Data System (ADS)

    Kim, Jungkwun; Yoon, Yong-Kyu; Allen, Mark G.

    2016-03-01

    This paper presents a computer-numerical-controlled ultraviolet light-emitting diode (CNC UV-LED) lithography scheme for three-dimensional (3D) microfabrication. The CNC lithography scheme utilizes sequential multi-angled UV light exposures along with a synchronized switchable UV light source to create arbitrary 3D light traces, which are transferred into the photosensitive resist. The system comprises a switchable, movable UV-LED array as a light source, a motorized tilt-rotational sample holder, and a computer-control unit. System operation is such that the tilt-rotational sample holder moves in a pre-programmed routine, and the UV-LED is illuminated only at desired positions of the sample holder during the desired time period, enabling the formation of complex 3D microstructures. This facilitates easy fabrication of complex 3D structures, which otherwise would have required multiple manual exposure steps as in the previous multidirectional 3D UV lithography approach. Since it is batch processed, processing time is far less than that of the 3D printing approach at the expense of some reduction in the degree of achievable 3D structure complexity. In order to produce uniform light intensity from the arrayed LED light source, the UV-LED array stage has been kept rotating during exposure. UV-LED 3D fabrication capability was demonstrated through a plurality of complex structures such as V-shaped micropillars, micropanels, a micro-‘hi’ structure, a micro-‘cat’s claw,’ a micro-‘horn,’ a micro-‘calla lily,’ a micro-‘cowboy’s hat,’ and a micro-‘table napkin’ array.

  5. Inclined nanoimprinting lithography-based 3D nanofabrication

    NASA Astrophysics Data System (ADS)

    Liu, Zhan; Bucknall, David G.; Allen, Mark G.

    2011-06-01

    We report a 'top-down' 3D nanofabrication approach combining non-conventional inclined nanoimprint lithography (INIL) with reactive ion etching (RIE), contact molding and 3D metal nanotransfer printing (nTP). This integration of processes enables the production and conformal transfer of 3D polymer nanostructures of varying heights to a variety of other materials includin