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Sample records for monolithic silicon microchannel

  1. Monolithic microchannel heatsink

    Science.gov (United States)

    Benett, William J.; Beach, Raymond J.; Ciarlo, Dino R.

    1996-01-01

    A silicon wafer has slots sawn in it that allow diode laser bars to be mounted in contact with the silicon. Microchannels are etched into the back of the wafer to provide cooling of the diode bars. To facilitate getting the channels close to the diode bars, the channels are rotated from an angle perpendicular to the diode bars which allows increased penetration between the mounted diode bars. This invention enables the fabrication of monolithic silicon microchannel heatsinks for laser diodes. The heatsinks have low thermal resistance because of the close proximity of the microchannels to the laser diode being cooled. This allows high average power operation of two-dimensional laser diode arrays that have a high density of laser diode bars and therefore high optical power density.

  2. Fabrication and characterization of monolithically integrated microchannel plates based on amorphous silicon.

    Science.gov (United States)

    Franco, Andrea; Geissbühler, Jonas; Wyrsch, Nicolas; Ballif, Christophe

    2014-04-04

    Microchannel plates are vacuum-based electron multipliers for particle--in particular, photon--detection, with applications ranging from image intensifiers to single-photon detectors. Their key strengths are large signal amplification, large active area, micrometric spatial resolution and picosecond temporal resolution. Here, we present the first microchannel plate made of hydrogenated amorphous silicon (a-Si:H) instead of lead glass. The breakthrough lies in the possibility of realizing amorphous silicon-based microchannel plates (AMCPs) on any kind of substrate. This achievement is based on mastering the deposition of an ultra-thick (80-120 μm) stress-controlled a-Si:H layer from the gas phase at temperatures of about 200 °C and micromachining the channels by dry etching. We fabricated AMCPs that are vertically integrated on metallic anodes of test structures, proving the feasibility of monolithic integration of, for instance, AMCPs on application-specific integrated circuits for signal processing. We show an electron multiplication factor exceeding 30 for an aspect ratio, namely channel length over aperture, of 12.5:1. This result was achieved for input photoelectron currents up to 100 pA, in the continuous illumination regime, which provides a first evidence of the a-Si:H effectiveness in replenishing the electrons dispensed in the multiplication process.

  3. Enhancing flow boiling heat transfer in microchannels for thermal management with monolithically-integrated silicon nanowires.

    Science.gov (United States)

    Li, D; Wu, G S; Wang, W; Wang, Y D; Liu, Dong; Zhang, D C; Chen, Y F; Peterson, G P; Yang, Ronggui

    2012-07-11

    Thermal management has become a critical issue for high heat flux electronics and energy systems. Integrated two-phase microchannel liquid-cooling technology has been envisioned as a promising solution, but with great challenges in flow instability. In this work, silicon nanowires were synthesized in situ in parallel silicon microchannel arrays for the first time to suppress the flow instability and to augment flow boiling heat transfer. Significant enhancement in flow boiling heat transfer performance was demonstrated for the nanowire-coated microchannel heat sink, such as an early onset of nucleate boiling, a delayed onset of flow oscillation, suppressed oscillating amplitudes of temperature and pressure drop, and an increased heat transfer coefficient.

  4. High pressure-resistant SU-8 microchannels for monolithic porous structure integration

    Science.gov (United States)

    Carlier, Julien; Chuda, Katarzyna; Arscott, Steve; Thomy, Vincent; Verbeke, Bernard; Coqueret, Xavier; Camart, Jean Christophe; Druon, Christian; Tabourier, Pierre

    2006-10-01

    Integrated lab-on-chip (LOC) microsystems dedicated to proteomic analysis require specific pretreatment steps such as protein trypsic digestion, concentration, desalting or separation of biological samples. These steps can be achieved thanks to porous monolithic polymers. This paper deals with the integration of such a polymer into SU-8 microchannels by using a multi-material technology (SU-8, Pyrex and silicon). A solution for the fabrication of complete polymer microchannels which are high pressure- and solvents-resistant is proposed. This technique uses the negative photoresist SU-8 which is compatible with the protein analysis performed here. Our process requires a novel technological step using a silane coupling agent. This modification of the SU-8/Pyrex interface leads to the fabrication of a 100 µm × 160 µm section microchannel (length of 3 cm), closed with a Pyrex® lid by SU-8 bonding resistant to 80 bar. An improvement of the SU-8/monolithic structure is also demonstrated thanks to a specific treatment of the polymer enabling good anchoring of the monolith in the microchannels, and the pressure-resistance tests were also achieved with the monolithic structure integrated in the microchannels. A digestion step of a protein sample of benzoylarginine ethyl ester in a SU-8 microchannel was achieved after the functionalization of a monolith anchored in the microchannel. Analysis by UV/VIS spectroscopy of this in situ digestion has been reported.

  5. Silicon-micromachined microchannel plates

    CERN Document Server

    Beetz, C P; Steinbeck, J; Lemieux, B; Winn, D R

    2000-01-01

    Microchannel plates (MCP) fabricated from standard silicon wafer substrates using a novel silicon micromachining process, together with standard silicon photolithographic process steps, are described. The resulting SiMCP microchannels have dimensions of approx 0.5 to approx 25 mu m, with aspect ratios up to 300, and have the dimensional precision and absence of interstitial defects characteristic of photolithographic processing, compatible with positional matching to silicon electronics readouts. The open channel areal fraction and detection efficiency may exceed 90% on plates up to 300 mm in diameter. The resulting silicon substrates can be converted entirely to amorphous quartz (qMCP). The strip resistance and secondary emission are developed by controlled depositions of thin films, at temperatures up to 1200 deg. C, also compatible with high-temperature brazing, and can be essentially hydrogen, water and radionuclide-free. Novel secondary emitters and cesiated photocathodes can be high-temperature deposite...

  6. Silicon-micromachined microchannel plates

    Energy Technology Data Exchange (ETDEWEB)

    Beetz, Charles P. E-mail: NanoSystem@aol.com; Boerstler, Robert; Steinbeck, John; Lemieux, Bryan; Winn, David R. E-mail: winn@fair1.fairfield.edu

    2000-03-11

    Microchannel plates (MCP) fabricated from standard silicon wafer substrates using a novel silicon micromachining process, together with standard silicon photolithographic process steps, are described. The resulting SiMCP microchannels have dimensions of {approx}0.5 to {approx}25 {mu}m, with aspect ratios up to 300, and have the dimensional precision and absence of interstitial defects characteristic of photolithographic processing, compatible with positional matching to silicon electronics readouts. The open channel areal fraction and detection efficiency may exceed 90% on plates up to 300 mm in diameter. The resulting silicon substrates can be converted entirely to amorphous quartz (qMCP). The strip resistance and secondary emission are developed by controlled depositions of thin films, at temperatures up to 1200 deg. C, also compatible with high-temperature brazing, and can be essentially hydrogen, water and radionuclide-free. Novel secondary emitters and cesiated photocathodes can be high-temperature deposited or nucleated in the channels or the first strike surface. Results on resistivity, secondary emission and gain are presented.

  7. Silicon-micromachined microchannel plates

    Science.gov (United States)

    Beetz, Charles P.; Boerstler, Robert; Steinbeck, John; Lemieux, Bryan; Winn, David R.

    2000-03-01

    Microchannel plates (MCP) fabricated from standard silicon wafer substrates using a novel silicon micromachining process, together with standard silicon photolithographic process steps, are described. The resulting SiMCP microchannels have dimensions of ˜0.5 to ˜25 μm, with aspect ratios up to 300, and have the dimensional precision and absence of interstitial defects characteristic of photolithographic processing, compatible with positional matching to silicon electronics readouts. The open channel areal fraction and detection efficiency may exceed 90% on plates up to 300 mm in diameter. The resulting silicon substrates can be converted entirely to amorphous quartz (qMCP). The strip resistance and secondary emission are developed by controlled depositions of thin films, at temperatures up to 1200°C, also compatible with high-temperture brazing, and can be essentially hydrogen, water and radionuclide-free. Novel secondary emitters and cesiated photocathodes can be high-temperature deposited or nucleated in the channels or the first strike surface. Results on resistivity, secondary emission and gain are presented.

  8. Monolithic silicon bolometers

    Science.gov (United States)

    Downey, P. M.; Jeffries, A. D.; Meyer, S. S.; Weiss, R.; Bachner, F. J.; Donnelly, J. P.; Lindley, W. T.; Mountain, R. W.; Silversmith, D. J.

    1984-01-01

    A new type of bolometer detector for the millimeter and submillimeter spectral range is described. The bolometer is constructed of silicon using integrated circuit fabrication techniques. Ion implantation is used to give controlled resistance vs temperature properties as well as extremely low 1/f noise contacts. The devices have been tested between 4.2 and 0.3 K. The best electrical NEP measured is 4 x 10 to the -16th W/Hz to the 1/2 at 0.35 K between 1- and 10-Hz modulation frequency. This device had a detecting area of 0.25 sq cm and a time constant of 20 msec at a bath temperature of 0.35 K.

  9. Microchannel Structures of Betavoltaic Silicon Convertors

    Directory of Open Access Journals (Sweden)

    V.V. Starkov

    2015-12-01

    Full Text Available The paper presents the first results of experimental research on the microchannel structures of betavoltaic silicon converters based on the 63Ni isotope. The areas for further optimization of constructive and technological performance with high conversion efficiency were detected experimentally.

  10. Flow characteristics in a trapezoidal silicon microchannel

    Science.gov (United States)

    Hao, Peng-Fei; He, Feng; Zhu, Ke-Qin

    2005-06-01

    In this paper, global pressure drop and velocity field were experimentally investigated for water flow in a trapezoidal silicon microchannel with a hydraulic diameter of 237 µm. Microscopic particle image velocimetry (micro-PIV) is used to obtain the velocity profiles at different locations of the microchannel for Reynolds numbers between 50 and 2800. For Re > 700, Δp-Re relationship deviates from the linear behavior and the deviation depends on the Re. The experimental results of the velocity field show that the deviation is due to the entrance effect in microchannel, and the entrance length in our experiments can be predicted byLe/Dh = (0.08-0.09)Re. Velocity profiles and root mean square values of the fluctuating velocity along the centerline obtained by micro-PIV indicate that the transition from laminar flow to turbulent flow occurs for Reynolds number ranging between 1500 and 1800. This result is consistent with the global measurements of the pressure drop.

  11. Thermoelectric Properties of Silicon Microchannel Plates Structures

    Energy Technology Data Exchange (ETDEWEB)

    Ci, P L; Shi, J; Wang, F; Sun, L; Xu, S H; Yang, P X; Wang, L W [Laboratory of Polar Materials and Devices, Ministry of Education, and Department of Electronic Engineering, East China Normal University, Shanghai 200241 (China); Chu, Paul K, E-mail: lwwang@ee.ecnu.edu.cn [Department of Physics and Material Sciences, City University of Hong Kong, Tat Chee Avenue, Kowloon (Hong Kong)

    2011-02-01

    We have fabricated silicon microchannel plates (MCPs) by photo-assisted electrochemical etching (PAECE) and determined the thermoelectric properties by measuring the Seebeck coefficient of the samples. The samples are composed of regular arrayed lattices with a width of about 5 {mu}m and spacing of about 1 {mu}m. The Seebeck coefficient along the edge of the lattice is 466 {mu}V/K. The silicon MCPs are potential materials for power generation and refrigeration. After oxidation from 30 minutes to 70 minutes and removing the silicon dioxide layer by buffered hydrofluoric acid, the samples show an improved coefficient as high as 1019 {mu}V/K after repeating oxidation and etching 5 times. Our results show that the Seebeck coefficient increases when the wall of the silicon MCPs is thinned.

  12. Gas flow characteristics in straight silicon microchannels

    Institute of Scientific and Technical Information of China (English)

    丁英涛; 姚朝晖; 沈孟育

    2002-01-01

    Experiments have been conducted to investigate nitrogen gas flow characteristics through four trapezoidal sili-con microchannels with different hydraulic diameters. The volume flow rate and pressure ratio are measured in theexperiments. It is found that the friction coefficient is no longer a constant, which is different from the conventionaltheory. The characteristics are first explained by the theoretical analysis. A simplified rectangular model (rectangularstraight channel model) is then proposed. The experimental results are compared with the theoretical predictions basedon the simplified rectangular model and the two-dimensional flow between the parallel-plate model which was usuallyuse The difference between the experimental data and the theoretical predictions is found in the high-pressure ratiocasesx. The influence of the gas compressibility effect based on the Boltzmann gas kinetic analysis method is studiedto interpret the discrepancy. We discuss two important factors affecting the application extent of different predictionmodels.

  13. Peltier effect in doped silicon microchannel plates

    Institute of Scientific and Technical Information of China (English)

    Ci Pengliang; Shi Jing; Wang Fei; Xu Shaohui; Yang Zhenya; Yang Pingxiong; Wang Lianwei; Gao Chen; Paul K.Chu

    2011-01-01

    The Seebeck coefficient is determined from silicon microchannel plates(Si MCPs)prepared by photoassisted electrochemical etching at room temperature(25 ℃).The coefficient of the sample with a pore size of 5 × 5μm2,spacing of 1 μm and thickness of about 150μm is-852 μV/K along the edge of the square pore.After doping with boron and phosphorus,the Seebeck coefficient diminishes to 256 μV/K and-117 μV/K along the edge of the square pore,whereas the electrical resistivity values are 7.5 × 10-3 Ω·cm and 1.9 × 10-3 Ω·cm,respectively.Our data imply that the Seebeck coefficient of the Si MCPs is related to the electrical resistivity and is consistent with that of bulk silicon.Based on the boron and phosphorus doped samples,a simple device is fabricated to connect the two type Si MCPs to evaluate the Peltier effect.When a proper current passes through the device,the Peltier effect is evidently observed.Based on the experimental data and the theoretical calculation,the estimated intrinsic figure of merit ZT of the unicouple device and thermal conductivity of the Si MCPs are 0.007 and 50 W/(m·K),respectively.

  14. Peltier effect in doped silicon microchannel plates

    Science.gov (United States)

    Pengliang, Ci; Jing, Shi; Fei, Wang; Shaohui, Xu; Zhenya, Yang; Pingxiong, Yang; Lianwei, Wang; Chen, Gao; Chu, Paul K.

    2011-12-01

    The Seebeck coefficient is determined from silicon microchannel plates (Si MCPs) prepared by photo-assisted electrochemical etching at room temperature (25 °C). The coefficient of the sample with a pore size of 5 × 5 μm2, spacing of 1 μm and thickness of about 150 μm is -852 μV/K along the edge of the square pore. After doping with boron and phosphorus, the Seebeck coefficient diminishes to 256 μV/K and -117 μV/K along the edge of the square pore, whereas the electrical resistivity values are 7.5 × 10-3 Ω·cm and 1.9 × 10-3 Ω·cm, respectively. Our data imply that the Seebeck coefficient of the Si MCPs is related to the electrical resistivity and is consistent with that of bulk silicon. Based on the boron and phosphorus doped samples, a simple device is fabricated to connect the two type Si MCPs to evaluate the Peltier effect. When a proper current passes through the device, the Peltier effect is evidently observed. Based on the experimental data and the theoretical calculation, the estimated intrinsic figure of merit ZT of the unicouple device and thermal conductivity of the Si MCPs are 0.007 and 50 W/(m·K), respectively.

  15. Microfabricated silicon gas chromatographic micro-channels: fabrication and performance

    Energy Technology Data Exchange (ETDEWEB)

    Matzke, C.M.; Kottenstette, R.J.; Casalnuovo, S.A.; Frye-Mason, G.C.; Hudson, M.L.; Sasaki, D.Y.; Manginell, R.P.; Wong, C.C.

    1998-11-01

    Using both wet and plasma etching, we have fabricated micro-channels in silicon substrates suitable for use as gas chromatography (GC) columns. Micro-channel dimensions range from 10 to 80 {micro}m wide, 200 to 400 {micro}m deep, and 10 cm to 100 cm long. Micro-channels 100 cm long take up as little as 1 cm{sup 2} on the substrate when fabricated with a high aspect ratio silicon etch (HARSE) process. Channels are sealed by anodically bonding Pyrex lids to the Si substrates. We have studied micro-channel flow characteristics to establish model parameters for system optimization. We have also coated these micro-channels with stationary phases and demonstrated GC separations. We believe separation performance can be improved by increasing stationary phase coating uniformity through micro-channel surface treatment prior to stationary phase deposition. To this end, we have developed microfabrication techniques to etch through silicon wafers using the HARSE process. Etching completely through the Si substrate facilitates the treatment and characterization of the micro- channel sidewalls, which domminate the GC physico-chemical interaction. With this approach, we separately treat the Pyrex lid surfaces that form the top and bottom surfaces of the GC flow channel.

  16. A new large area monolithic silicon telescope

    CERN Document Server

    Tudisco, S; Cabibbo, M; Cardella, G; De Geronimo, G; Di Pietro, A; Fallica, G; Figuera, P; Musumarra, A; Papa, M; Pappalardo, G S; Rizzo, F; Valvo, G

    1999-01-01

    A new prototype of large area (20x20 mm sup 2) monolithic silicon telescope with an ultrathin DELTA E stage (1 mu m) has been built and tested. A particular mask for the ground electrode has been developed to improve the charge collection reducing the induction between the E and DELTA E stages. A special designed preamplifier has been used for the readout of the signal from the DELTA E stage to overcome the problem of the large input capacitance (40 nF). A rather low energy threshold charge discrimination has been obtained. Small side effects due to the electric field deformation near the ground electrode were observed and quantified.

  17. Silicon Wafer Fabrication and Microchannel for Cooling System in ALICE ITS

    CERN Document Server

    Pasuwan, Patrawan

    2013-01-01

    My summer student project covered details of the upgrade of Inner Tracking System (ITS) of the ALICE detector. The tasks are divided in two parts. First was on silicon wafer dicing technology and its resistivity under the supervision of Petra Riedler. Next was on silicon wafer microfabrication and cooling system in microchannel under the supervision of Andrea Francescon. ITS upgrade was proposed for better detection performance and reduction of budget. Detectors in the ITS are composed of monolithic silicon pixel chips. The thickness of the chips was proposed to be 50 μm so that particles that pass through them do not lose too much momentum. Working with very thin chips requires suitable dicing technology. Sum- mary of dicing technology is proposed for the most suitable dicing technique. Properties of the chip can be denoted by observing its resistivity. Literature reviews on surface resistivity profile measurement is represented for consideration. Cooling system is very important for the detector. Fluid t...

  18. Monolithic Perovskite Silicon Tandem Solar Cells with Advanced Optics

    Energy Technology Data Exchange (ETDEWEB)

    Goldschmidt, Jan C.; Bett, Alexander J.; Bivour, Martin; Blasi, Benedikt; Eisenlohr, Johannes; Kohlstadt, Markus; Lee, Seunghun; Mastroianni, Simone; Mundt, Laura; Mundus, Markus; Ndione, Paul; Reichel, Christian; Schubert, Martin; Schulze, Patricia S.; Tucher, Nico; Veit, Clemens; Veurman, Welmoed; Wienands, Karl; Winkler, Kristina; Wurfel, Uli; Glunz, Stefan W.; Hermle, Martin

    2016-11-14

    For high efficiency monolithic perovskite silicon tandem solar cells, we develop low-temperature processes for the perovskite top cell, rear-side light trapping, optimized perovskite growth, transparent contacts and adapted characterization methods.

  19. On the eruptive boiling in silicon-based microchannels

    Energy Technology Data Exchange (ETDEWEB)

    Lee, P.C.; Pan, Chin [Department of Engineering and System Science, National Tsing Hua University, Hsinchu 30043 (China)

    2008-09-15

    This study investigates experimentally eruptive boiling in a silicon-based rectangular microchannel with a hydraulic diameter of 33.7 {mu}m, a width of 99.8 {mu}m and a depth-to-width ratio of 0.203. The microchannel is made of SOI wafer and prepared using bulk micro-machining and anodic bonding. The surface roughness for both the bottom and the side walls was measured using an atomic force microscope. The evolution of the eruptive boiling of water in the smooth microchannel was clearly observed using an ultra high-speed video camera (up to 50,000 frames/s) at mass fluxes of 417 and 625 kg/m{sup 2} s and a heat flux from 14.9 to 372 kW/m{sup 2}. It is confirmed that eruptive boiling is a form of rapid bubble nucleation after which the bubble merges with a slug bubble downstream in a short distance or evolve to a slug bubble. The bubble frequency in all of the cases studied is provided. Eruptive boiling may be predicted classically with nano-sized cavities that are consistent with the measured surface roughness. (author)

  20. Optimization of the thermal performance of multi-layer silicon microchannel heat sinks

    Directory of Open Access Journals (Sweden)

    Xu Shanglong

    2016-01-01

    Full Text Available The objective is to optimize the configuration sizes and thermal performance of a multilayer silicon microchannel heat sink by the thermal resistance network model. The effect of structural parameter on the thermal resistance is analyzed by numercal simulation. Taking the thermal resistance as an objective function, a nonlinear and multi-constrained optimization model are proposed for the silicon microchannel heat sink in electronic chips cooling. The sequential quadratic programming (SQP method is used to do the optimization design of the configuration sizes of the microchannel. For the heat sink with the size of 20mm×20mm and the power of 400 W, the optimized microchannel number, layer, height and width are 40 and 2, 2.2mm and 0.2mm, respectively, and its corresponding total thermal resistance for whole microchannel heat sink is 0.0424 K/W.

  1. 10Gbps monolithic silicon FTTH transceiver for PON

    Science.gov (United States)

    Zhang, J.; Liow, T. Y.; Lo, G. Q.; Kwong, D. L.

    2010-05-01

    We propose a new passive optical network (PON) configuration and a novel silicon photonic transceiver architecture for optical network unit (ONU), eliminating the need for an internal laser source in ONU. We adopt dual fiber network configuration. The internal light source in each of the ONUs is eliminated. Instead, an extra seed laser source in the optical line termination (OLT) operates in continuous wave mode to serve the ONUs in the PON as a shared and centralized laser source. λ1 from OLT Tx and λ2 from the seed laser are combined by using a WDM combiner and connected to serve the multiple ONUs through the downstream fibers. The ONUs receive the data in λ1. Meanwhile, the ONUs encode and transmit data in λ2, which are sent back to OLT. The monolithic ONU transceiver contains a wavelength-division-multiplexing (WDM) filter component, a silicon modulator and a Ge photo-detector. The WDM in ONU selectively guides λ1 to the Ge-PD where the data in λ1 are detected and converted to electrical signals, and λ2 to the transmitter where the light is modulated by upstream data. The modulated optical signals in λ2 from ONUs are connected back to OLT through upstream fibers. The monolithic ONU transceiver chip size is only 2mm by 4mm. The crosstalk between the Tx and Rx is measured to be less than -20dB. The transceiver chip is integrated on a SFP+ transceiver board. Both Tx and Rx demonstrated data rate capabilities of up to 10Gbps. By implementing this scheme, the ONU transceiver size can be significantly reduced and the assembly processes will be greatly simplified. The results demonstrate the feasibility of mass manufacturing monolithic silicon ONU transceivers via low cost

  2. Development of betavoltaic cell technology production based on microchannel silicon and its electrical parameters evaluation.

    Science.gov (United States)

    Krasnov, A A; Starkov, V V; Legotin, S A; Rabinovich, O I; Didenko, S I; Murashev, V N; Cheverikin, V V; Yakimov, E B; Fedulova, N A; Rogozev, B I; Laryushkin, A S

    2017-03-01

    In the paper a manufacturing process of three-dimensional (3D) microchannel structure by silicon (Si) anodic etching was discussed. The possibility of microchannels formation allows to increase the active area more than 100 times. In this structure the p-n junction on the whole Si surface was formed. The obtained data allowed to evaluate the characteristics of the betavoltaic converter with a 3D structure by using isotope 63Ni with a specific activity of 10Ci/g.

  3. Initial results for the silicon monolithically interconnected solar cell product

    Science.gov (United States)

    Dinetta, L. C.; Shreve, K. P.; Cotter, J. E.; Barnett, A. M.

    1995-01-01

    This proprietary technology is based on AstroPower's electrostatic bonding and innovative silicon solar cell processing techniques. Electrostatic bonding allows silicon wafers to be permanently attached to a thermally matched glass superstrate and then thinned to final thicknesses less than 25 micron. These devices are based on the features of a thin, light-trapping silicon solar cell: high voltage, high current, light weight (high specific power) and high radiation resistance. Monolithic interconnection allows the fabrication costs on a per watt basis to be roughly independent of the array size, power or voltage, therefore, the cost effectiveness to manufacture solar cell arrays with output powers ranging from milliwatts up to four watts and output voltages ranging from 5 to 500 volts will be similar. This compares favorably to conventionally manufactured, commercial solar cell arrays, where handling of small parts is very labor intensive and costly. In this way, a wide variety of product specifications can be met using the same fabrication techniques. Prototype solar cells have demonstrated efficiencies greater than 11%. An open-circuit voltage of 5.4 volts, fill factor of 65%, and short-circuit current density of 28 mA/sq cm at AM1.5 illumination are typical. Future efforts are being directed to optimization of the solar cell operating characteristics as well as production processing. The monolithic approach has a number of inherent advantages, including reduced cost per interconnect and increased reliability of array connections. These features make this proprietary technology an excellent candidate for a large number of consumer products.

  4. One-shot genetic analysis in monolithic Silicon/Pyrex microdevices.

    Science.gov (United States)

    Potrich, C; Lunelli, L; Pasquardini, L; Sonn, D; Vozzi, D; Dallapiccola, R; Marocchi, L; Ferrante, I; Rossotto, O; Pederzolli, C

    2012-12-01

    Modern Lab-on-a-chip (LOC) platforms for genomic applications integrate several biological tasks in a single device. Combination of these processes into a single device minimizes sample loss and contamination problems as well as reducing analysis time and costs. Here we present a study of a microchip platform aimed at analyzing issues arising from the combination of different functions, such as DNA purification from blood, target amplification by PCR and DNA detection in a single silicon-based device. DNA purification is realized through two different strategies: 1) amine groups coating microchannel surfaces and 2) magnetic nanoparticles coated by chitosan. In the first strategy silicon/Pyrex microdevices coated with 3-aminopropyltriethoxysilane (APTES) or 3-2-(2-aminoethylamino)-ethylamino]-propyltrimethoxysilane (AEEA) were examined and their efficiency in human genomic DNA adsorption/desorption was evaluated. APTES treatment was the most suitable for the purification of a reasonable amount of DNA in a state suitable for the following PCR step. The second strategy has instead the main advantage of avoiding an elution step, since the DNA adsorbed on the magnetic nanoparticles can be used as PCR template. On-chip PCR was performed in a custom thermocycler, while the detection of PCR products was carried out by fluorescence reading. A complete genetic analysis was demonstrated on the monolithic silicon/Pyrex microchip, starting from less than 1 [Formula: see text]L of human whole blood and arriving at SNPs identification. The successful integration of DNA purification, amplification and detection on a single microdevice was proven without the need for biological passivation steps and possibly simplifying the realization of genomic detection devices.

  5. Impact of wall hydrophobicity on condensation flow and heat transfer in silicon microchannels

    Science.gov (United States)

    Fang, Chen; Steinbrenner, Julie E.; Wang, Fu-Min; Goodson, Kenneth E.

    2010-04-01

    While microchannel condensation has been the subject of several recent studies, the critical impact of wall hydrophobicity on the microchannel condensation flow has received very little attention. The paper experimentally studies steam condensation in a silicon microchannel 286 µm in hydraulic diameter with three different wall hydrophobicities. It is found that the channel surface wettability has a significant impact on the flow pattern, pressure drop and heat transfer characteristic. Spatial flow pattern transition is observed in both hydrophobic and hydrophilic channels. In the hydrophobic channel, the transition from dropwise/slugwise flow to plug flow is induced by the slug instability. In the hydrophilic channel, the flow transition is characterized by the periodic bubble detachment, a process in which pressure evolution is found important. Local temperature measurement is conducted and heat flux distribution in the microchannel is reconstructed. For the same inlet vapor flux and temperature, the hydrophobic microchannel yields higher heat transfer rate and pressure drop compared to the hydrophilic channel. The difference is attributed to the distinction in flow pattern and heat transfer mechanism dictated by the channel hydrophobicity. This study highlights the importance of the channel hydrophobicity control for the optimization of the microchannel condenser.

  6. Position and time resolution measurements with a microchannel plate image intensifier: A comparison of monolithic and pixelated CeBr{sub 3} scintillators

    Energy Technology Data Exchange (ETDEWEB)

    Ackermann, Ulrich, E-mail: ulrich.ackermann@unibw.de [Universität der Bundeswehr München, Institut für angewandte Physik und Messtechnik (LRT2), Werner-Heisenberg-Weg 39, 85577 Neubiberg (Germany); Eschbaumer, Stephan, E-mail: stephan.eschbaumer@unibw.de [Universität der Bundeswehr München, Institut für angewandte Physik und Messtechnik (LRT2), Werner-Heisenberg-Weg 39, 85577 Neubiberg (Germany); Bergmaier, Andreas, E-mail: andreas.bergmaier@unibw.de [Universität der Bundeswehr München, Institut für angewandte Physik und Messtechnik (LRT2), Werner-Heisenberg-Weg 39, 85577 Neubiberg (Germany); Egger, Werner, E-mail: werner.egger@unibw.de [Universität der Bundeswehr München, Institut für angewandte Physik und Messtechnik (LRT2), Werner-Heisenberg-Weg 39, 85577 Neubiberg (Germany); Sperr, Peter, E-mail: peter.sperr@unibw.de [Universität der Bundeswehr München, Institut für angewandte Physik und Messtechnik (LRT2), Werner-Heisenberg-Weg 39, 85577 Neubiberg (Germany); Greubel, Christoph, E-mail: christoph.greubel@unibw.de [Universität der Bundeswehr München, Institut für angewandte Physik und Messtechnik (LRT2), Werner-Heisenberg-Weg 39, 85577 Neubiberg (Germany); and others

    2016-07-01

    To perform Four Dimensional Age Momentum Correlation measurements in the near future, where one obtains the positron lifetime in coincidence with the three dimensional momentum of the electron annihilating with the positron, we have investigated the time and position resolution of two CeBr{sub 3} scintillators (monolithic and an array of pixels) using a Photek IPD340/Q/BI/RS microchannel plate image intensifier. The microchannel plate image intensifier has an active diameter of 40 mm and a stack of two microchannel plates in chevron configuration. The monolithic CeBr{sub 3} scintillator was cylindrically shaped with a diameter of 40 mm and a height of 5 mm. The pixelated scintillator array covered the whole active area of the microchannel plate image intensifier and the shape of each pixel was 2.5·2.5·8 mm{sup 3} with a pixel pitch of 3.3 mm. For the monolithic setup the measured mean single time resolution was 330 ps (FWHM) at a gamma energy of 511 keV. No significant dependence on the position was detected. The position resolution at the center of the monolithic scintillator was about 2.5 mm (FWHM) at a gamma energy of 662 keV. The single time resolution of the pixelated crystal setup reached 320 ps (FWHM) in the region of the center of the active area of the microchannel plate image intensifier. The position resolution was limited by the cross-section of the pixels. The gamma energy for the pixel setup measurements was 511 keV.

  7. Oxidation of Self Lift-off Silicon Microchannels%自分离硅微通道的氧化

    Institute of Scientific and Technical Information of China (English)

    田菲; 袁丁; 王连卫

    2009-01-01

    本文研究了自分离硅微通道(self lift-off silicon microchannels)的氧化问题.自分离是在特定的实验条件下,在完成电化学刻蚀后,硅微通道可以自动和衬底分离的一种新技术.研究发现,在使用传统的干氧-湿氧-干氧氧化化过程中,硅微通道出现了弯曲变形的现象.微通道越薄,其形变越大.通过使用较厚的硅微通道以及在干-湿-干氧化过程之前增加了干氧,以及先进行激光切割的步骤,改善和基本消除了弯曲变形的现象.%The oxidation of the self lift-off silicon microchannels is studied. Self lift-off silicon micro-channels are fabricated by a new technology; under certain experimental conditions, the silicon micro-channels can lift off from the substrate automatically after electrochemical etching. In the process of the traditional dry-wet-dry oxidation, damages and distortion of the silicon microchannels occurred. It was found that the thinner the silicon microchannels, the more serious the distortion and damages are. By u-sing thicker silicon microchannels and adding a procedure of dry oxidation before the dry-wet-dry oxi-dation, the damages and distortion of the silicon microchannels can be eliminated.

  8. Hybrid microsystem with functionalized silicon substrate and PDMS sample operating microchannel: A reconfigurable microfluidics scheme

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    A hybrid microsystem with separately functioned temperature controlling substrate and sample operating fluidic microchannel was developed to demonstrate a reconfigurable microfluidics scheme.The temperature controlling substrate integrated a micro heater and a temperature sensor by using traditional silicon-based micromechanical system(MEMS)technique,which guaranteed high performance and robust reliability for repeatable usage.The sample operating fluidic microchannel was prepared by poly-(dimethylsiloxane) (PDMS)based soft lithography technique,which made it cheap enough for disposable applications.The PDMS microchannel chip was attached to the temperature controlling substrate for reconfigurable thermal applications.A thin PDMS film was used to seal the microchannel and bridge the functionalized substrate and the sample inside the channel,which facilitated heat transferring and prevented sample contaminating the temperature controlling substrate.Demonstrated by a one dimensional thermal resistance model,the thin PDMS film was important for the present reconfiguration applications.Thermal performance of this hybrid microsystem was examined,and the experimental results demonstrated that the chip system could work stably over hours with temperature variation less than 0.1oC.Multiple PDMS microchannel chips were tested on one heating substrate sequentially with a maximum intra-chip temperature difference of 1.0oC.DNA extracted from serum of a chronic hepatitis B virus(HBV)patient was amplified by this hybrid microsystem and the gel electrophoresis result indicated that the present reconfigurable microfluidic scheme worked successfully.

  9. Evaporative CO2 cooling using microchannels etched in silicon for the future LHCb vertex detector

    CERN Document Server

    Nomerotski, A; Collins, P; Dumps, R; Greening, E; John, M; Mapelli, A; Leflat, A; Li, Y; Romagnoli, G; Verlaat, B

    2013-01-01

    The extreme radiation dose received by vertex detectors at the Large Hadron Collider dictates stringent requirements on their cooling systems. To be robust against radiation damage, sensors should be maintained below -20 degree C and at the same time, the considerable heat load generated in the readout chips and the sensors must be removed. Evaporative CO2 cooling using microchannels etched in a silicon plane in thermal contact with the readout chips is an attractive option. In this paper, we present the first results of microchannel prototypes with circulating, two-phase CO2 and compare them to simulations. We also discuss a practical design of upgraded VELO detector for the LHCb experiment employing this approach.

  10. Thermal and hydrodynamic studies for micro-channel cooling for large area silicon sensors in high energy physics experiments

    CERN Document Server

    Flaschel, Nils; Diez, Sergio; Gerboles, Marta; Gregor, Ingrid-Maria; Jorda, Xavier; Mas, Roser; Mussgiller, Andreas; Quirion, David; Tackmann, Kerstin; Ullan, Miguel

    2016-01-01

    Micro-channel cooling initially aiming at small-sized high-power integrated circuits is being transferred to the field of high energy physics for thermal management of silicon tracking detectors. Today's prospects of micro-fabricating silicon opens a door to a more lightweight and direct cooling of detector modules. The challenge in high energy physics is to save material in the detector construction and to cool large areas. DESY and IMB-CNM are investigating micro-channel cooling as a candidate for a future cooling system for silicon detectors in a generic research and development approach. The work presented in this paper includes the production and the hydrodynamic and thermal testing of a micro-channel equipped prototype. Furthermore, the device was simulated using finite element methods.

  11. A monolithic integrated micro direct methanol fuel cell based on sulfo functionalized porous silicon

    Science.gov (United States)

    Wang, M.; Lu, Y. X.; Liu, L. T.; Wang, X. H.

    2016-11-01

    In this paper, we demonstrate a monolithic integrated micro direct methanol fuel cell (μDMFC) for the first time. The monolithic integrated μDMFC combines proton exchange membrane (PEM) and Pt nanocatalysts, in which PEM is achieved by the functionalized porous silicon membrane and 3D Pt nanoflowers being synthesized in situ on it as catalysts. Sulfo groups functionalized porous silicon membrane serves as a PEM and a catalyst support simultaneously. The μDMFC prototype achieves an open circuit voltage of 0.3 V, a maximum power density of 5.5 mW/cm2. The monolithic integrated μDMFC offers several desirable features such as compatibility with micro fabrication techniques, an undeformable solid PEM and the convenience of assembly.

  12. Monolithic integration of erbium-doped amplifiers with silicon-on-insulator waveguides.

    Science.gov (United States)

    Agazzi, Laura; Bradley, Jonathan D B; Dijkstra, Meindert; Ay, Feridun; Roelkens, Gunther; Baets, Roel; Wörhoff, Kerstin; Pollnau, Markus

    2010-12-20

    Monolithic integration of Al2O3:Er3+ amplifier technology with passive silicon-on-insulator waveguides is demonstrated. A signal enhancement of >7 dB at 1533 nm wavelength is obtained. The straightforward wafer-scale fabrication process, which includes reactive co-sputtering and subsequent reactive ion etching, allows for parallel integration of multiple amplifier and laser sections with silicon or other photonic circuits on a chip.

  13. Thermal and hydrodynamic studies for micro-channel cooling for large area silicon sensors in high energy physics experiments

    Energy Technology Data Exchange (ETDEWEB)

    Flaschel, Nils; Ariza, Dario; Diez, Sergio; Gregor, Ingrid-Maria; Tackmann, Kerstin [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany); Gerboles, Marta; Jorda, Xavier; Mas, Roser; Quirion, David; Ullan, Miguel [Centro Nacional de Microelectronica, Barcelona (Spain)

    2017-01-15

    Micro-channel cooling initially aiming at small-sized high-power integrated circuits is being transferred to the field of high energy physics. Today's prospects of micro-fabricating silicon opens a door to a more direct cooling of detector modules. The challenge in high energy physics is to save material in the detector construction and to cool large areas. In this paper, we are investigating micro-channel cooling as a candidate for a future cooling system for silicon detectors in a generic research and development approach. The work presented in this paper includes the production and the hydrodynamic and thermal testing of a micro-channel equipped prototype optimized to achieve a homogeneous flow distribution. Furthermore, the device was simulated using finite element methods.

  14. Design and realisation of a quasi monolithic silicon load cell

    NARCIS (Netherlands)

    Wensink, H.; Wiegerink, R.J.; Zwijze, A.F.; Boer, de M.J.; Elwenspoek, M.C.

    1998-01-01

    In this paper, the first silicon load cell is presented designed for measuring a load up to 1000 kg. A prototype has been realised. An improved cryogenic RIE process with high aspect ratio was developed for the fabrication of thin springs. Low temperature silicon direct bonding was used for the fina

  15. Optimal Design of Silicon-based Chips for Piezo-induced Ultrasound Resonances in Embedded Microchannels

    Science.gov (United States)

    Garofalo, F.; Laurell, T.; Bruus, H.

    We present a variational formulation of the governing equations and introduce global indicators to describe the behavior of acoustofluidic devices driven at resonance frequencies by means of a piezoelectric transducer. The individuation of the correct Lagrangian densities for the different parts constituting the device (the piezo transducer, the silicon walls, the fluid-filled microchannel, and the glass lid) allows for the introduction of the weak formulation used in the finite element discretization of the equations describing the system in its oscillatory regime. Additionally, the knowledge of the Lagrangian density leads to the derivation of the correct structure of the Hamiltonian density, i.e. the energy density, which is important for the quantification of the energy content of the whole system and its individual parts. Specifically, the energy content of the embedded microchannel is quantified by means of the acoustofluidic yield η defined as the ratio between the energy in the channel and the total energy. From the standpoint of acoustophoretic application, the introduction of the acoustophoretic mean orientation allows us to identify the frequencies for which an acoustophoretic effect, i.e. the lateral motion of particle dragged by the axial main flow, is particularly strong. Finally, the connection between the mechanical and electrical degrees of freedom of the system is addressed. This is important for proper determination of the dissipated power, and it may lead to the detection of resonance states by means of purely electrical measurements. Numerical simulations and preliminary experimental results show some features of the model introduced.

  16. Monolithic integration of germanium-on-insulator p-i-n photodetector on silicon.

    Science.gov (United States)

    Nam, Ju Hyung; Afshinmanesh, Farzaneh; Nam, Donguk; Jung, Woo Shik; Kamins, Theodore I; Brongersma, Mark L; Saraswat, Krishna C

    2015-06-15

    A germanium-on-insulator (GOI) p-i-n photodetector, monolithically integrated on a silicon (Si) substrate, is demonstrated. GOI is formed by lateral-overgrowth (LAT-OVG) of Ge on silicon dioxide (SiO(2)) through windows etched in SiO(2) on Si. The photodetector shows excellent diode characteristics with high on/off ratio (6 × 10(4)), low dark current, and flat reverse current-voltage (I-V) characteristics. Enhanced light absorption up to 1550 nm is observed due to the residual biaxial tensile strain induced during the epitaxial growth of Ge caused by cooling after the deposition. This truly Si-compatible Ge photodetector using monolithic integration enables new opportunities for high-performance GOI based photonic devices on Si platform.

  17. Monolithic Silicon Photodetector - Detector of Ionizing Radiation Based on Functional Integrated MOS Structures

    Directory of Open Access Journals (Sweden)

    S.A. Legotin

    2014-07-01

    Full Text Available This paper describes the principle of operation, construction, architecture and fabrication of a new type of monolithic silicon coordinate photodetector - detector of optical and ionizing radiation (MSCP on the basis of functional integrated MOS structures. The analytical estimation of electrophysical characteristics MSCP is given. It is shown that MSCP is a specialized monolithic silicon VLSI containing two-dimensional pixel array with high and low voltage functionally integrated structures (FIS and peripheral electronic circuits of amplification and signal processing matrix. Estimations and presents comparative characteristics are presented. They show potential MSCP possibilities for registration of optical and ionizing radiation. Experimental results of α-particles and electrons registration. The possible areas of application, with the possibility of its use in a wide X-ray panels medical supplies, X-rays, etc are considered.

  18. Beam characterization of a monolithic ΔE/E silicon device

    Energy Technology Data Exchange (ETDEWEB)

    Agosteo, S. [INFN, Sezione di Milano, via Celoria 16, 20133 Milano (Italy); Politecnico di Milano, Dipartimento di Energia, Sezione di Ingegneria Nucleare - CeSNEF, via Ponzio 34/3, 20133 Milano (Italy); Barcellan, L. [INFN, Sezione di Padova, via Marzolo 8, 35131 Padova (Italy); Borsato, E. [INFN, Sezione di Padova, via Marzolo 8, 35131 Padova (Italy); Università di Padova, Dipartimento di Fisica e Astronomia, via Marzolo 8, 35131 Padova (Italy); D' Angelo, G. [INFN, Sezione di Milano, via Celoria 16, 20133 Milano (Italy); Politecnico di Milano, Dipartimento di Energia, Sezione di Ingegneria Nucleare - CeSNEF, via Ponzio 34/3, 20133 Milano (Italy); Dal Corso, F. [INFN, Sezione di Padova, via Marzolo 8, 35131 Padova (Italy); Fazzi, A. [INFN, Sezione di Milano, via Celoria 16, 20133 Milano (Italy); Politecnico di Milano, Dipartimento di Energia, Sezione di Ingegneria Nucleare - CeSNEF, via Ponzio 34/3, 20133 Milano (Italy); Gonella, F. [INFN, Sezione di Padova, via Marzolo 8, 35131 Padova (Italy); Introini, M.V. [INFN, Sezione di Milano, via Celoria 16, 20133 Milano (Italy); Politecnico di Milano, Dipartimento di Energia, Sezione di Ingegneria Nucleare - CeSNEF, via Ponzio 34/3, 20133 Milano (Italy); Lippi, I. [INFN, Sezione di Padova, via Marzolo 8, 35131 Padova (Italy); Lorenzoli, M. [INFN, Sezione di Milano, via Celoria 16, 20133 Milano (Italy); Politecnico di Milano, Dipartimento di Energia, Sezione di Ingegneria Nucleare - CeSNEF, via Ponzio 34/3, 20133 Milano (Italy); Pegoraro, M. [INFN, Sezione di Padova, via Marzolo 8, 35131 Padova (Italy); Pola, A.; Varoli, V. [INFN, Sezione di Milano, via Celoria 16, 20133 Milano (Italy); Politecnico di Milano, Dipartimento di Energia, Sezione di Ingegneria Nucleare - CeSNEF, via Ponzio 34/3, 20133 Milano (Italy); and others

    2015-04-11

    A full characterization of a ΔE/E monolithic silicon detector especially developed for microdosimetry was performed using monochromatic beams of α-particles and protons at the Italian National Laboratories of Legnaro at the CN van de Graaff accelerator. The investigation was performed in order to evaluate the limitations and the systematic effects affecting its use as a microdosimeter. The results can be extended to the standard use of these kind of devices as particle identifiers.

  19. Towards monolithic integration of germanium light sources on silicon chips

    Science.gov (United States)

    Saito, Shinichi; Zaher Al-Attili, Abdelrahman; Oda, Katsuya; Ishikawa, Yasuhiko

    2016-04-01

    Germanium (Ge) is a group-IV indirect band gap semiconductor, and therefore bulk Ge cannot emit light efficiently. However, the direct band gap energy is close to the indirect one, and significant engineering efforts are being made to convert Ge into an efficient gain material monolithically integrated on a Si chip. In this article, we will review the engineering challenges of developing Ge light sources fabricated using nano-fabrication technologies compatible with complementary metal-oxide-semiconductor processes. In particular, we review recent progress in applying high-tensile strain to Ge to reduce the direct band gap. Another important technique is doping Ge with donor impurities to fill the indirect band gap valleys in the conduction band. Realization of carrier confinement structures and suitable optical cavities will be discussed. Finally, we will discuss possible applications of Ge light sources in potential photonics-electronics convergent systems.

  20. On-chip generation and demultiplexing of quantum correlated photons using a silicon-silica monolithic photonic integration platform.

    Science.gov (United States)

    Matsuda, Nobuyuki; Karkus, Peter; Nishi, Hidetaka; Tsuchizawa, Tai; Munro, William J; Takesue, Hiroki; Yamada, Koji

    2014-09-22

    We demonstrate the generation and demultiplexing of quantum correlated photons on a monolithic photonic chip composed of silicon and silica-based waveguides. Photon pairs generated in a nonlinear silicon waveguide are successfully separated into two optical channels of an arrayed-waveguide grating fabricated on a silica-based waveguide platform.

  1. Light prototype support using micro-channel technology as high efficiency system for silicon pixel detector cooling

    Energy Technology Data Exchange (ETDEWEB)

    Bosi, F., E-mail: filippo.bosi@pi.infn.it [INFN Pisa, Largo B. Pontecorvo 3, 56127 Pisa (Italy); Balestri, G.; Ceccanti, M.; Mammini, P.; Massa, M.; Petragnani, G.; Ragonesi, A.; Soldani, A. [INFN Pisa, Largo B. Pontecorvo 3, 56127 Pisa (Italy)

    2011-09-11

    The development of micro-scale mechanical systems has been moving rapidly, allowing an opportunity to the semiconductor detectors to have ever more power located on the active region. Miniaturization associated with micro-channel technologies allows the design of micro-system structures that are able to cool silicon pixel detectors with power of the order of some W/cm{sup 2} with thickness less than 0.3% of radiation length. We present the design and thermo-hydraulic test results for low material budget support and cooling obtained through forced liquid convection in micro-channels, developed for the innermost layer (Layer 0) of SuperB silicon vertex tracker.

  2. Design and characterization of ultra-stretchable monolithic silicon fabric

    KAUST Repository

    Rojas, Jhonathan Prieto

    2014-10-13

    Stretchable electronic systems can play instrumental role for reconfigurable macro-electronics such as distributed sensor networks for wearable and bio-integrated electronics. Typically, polymer composite based materials and its deterministic design as interconnects are used to achieve such systems. Nonetheless, non-polymeric inorganic silicon is the predominant material for 90% of electronics. Therefore, we report the design and fabrication of an all silicon based network of hexagonal islands connected through spiral springs to form an ultra-stretchable arrangement for complete compliance to highly asymmetric shapes. Several design parameters are considered and their validation is carried out through finite element analysis. The fabrication process is based on conventional microfabrication techniques and the measured stretchability is more than 1000% for single spirals and area expansions as high as 30 folds in arrays. The reported method can provide ultra-stretchable and adaptable electronic systems for distributed network of high-performance macro-electronics especially useful for wearable electronics and bio-integrated devices.

  3. Monolithic electrically injected nanowire array edge-emitting laser on (001) silicon

    KAUST Repository

    Frost, Thomas

    2014-08-13

    A silicon-based laser, preferably electrically pumped, has long been a scientific and engineering goal. We demonstrate here, for the first time, an edge-emitting InGaN/GaN disk-in-nanowire array electrically pumped laser emitting in the green (λ = 533 nm) on (001) silicon substrate. The devices display excellent dc and dynamic characteristics with values of threshold current density, differential gain, T0 and small signal modulation bandwidth equal to 1.76 kA/cm2, 3 × 10-17 cm2, 232 K, and 5.8 GHz respectively under continuous wave operation. Preliminary reliability measurements indicate a lifetime of 7000 h. The emission wavelength can be tuned by varying the alloy composition in the quantum disks. The monolithic nanowire laser on (001)Si can therefore address wide-ranging applications such as solid state lighting, displays, plastic fiber communication, medical diagnostics, and silicon photonics. © 2014 American Chemical Society.

  4. A bioanalytical microsystem for protein and DNA sensing based on a monolithic silicon optoelectronic transducer

    Energy Technology Data Exchange (ETDEWEB)

    Misiakos, K [Microelectronics Institute, NCSR ' Demokritos' , 15310, Athens (Greece); Petrou, P S [Immunoassay Lab., I/R-RP, NCSR ' Demokritos' , 15310, Athens (Greece); Kakabakos, S E [Immunoassay Lab., I/R-RP, NCSR ' Demokritos' , 15310, Athens (Greece); Ruf, H H [Fraunhofer Institute of Biomedical Engineering (IBMT) and University of Saarland, 66386, St Ingbert (Germany); Ehrentreich-Foerster, E [Department of Molecular Bioanalytics and Bioelectronics, Fraunhofer Institute for Biomedical Engineering, D-14558 Nuthetal (Germany); Bier, F F [Department of Molecular Bioanalytics and Bioelectronics, Fraunhofer Institute for Biomedical Engineering, D-14558 Nuthetal (Germany)

    2005-01-01

    A bioanalytical microsystem that is based on a monolithic silicon optical transducer and a microfluidic module and it is appropriate for real-time sensing of either DNA or protein analytes is presented. The optical transducer monolithically integrates silicon avalanche diodes as light sources, silicon nitride optical fibers and detectors and efficiently intercouples these optical elements through a self-alignment technique. After hydrophilization and silanization of the transducer surface, the biomolecular probes are immobilized through physical adsorption. Detection is performed through reaction of the immobilized biomolecules with gold nanoparticle labeled counterpart molecules. The binding of these molecules within the evanescent field at the surface of the optical fiber cause attenuated total reflection of the waveguided modes and reduction of the detector photocurrent. Using the developed microsystem, determination of single nucleotide polymorphism (SNP) in the gene of the human phenol sulfotransferase SULT1A1 was achieved. Full-matching hybrid resulted in 4-5 times higher signals compared to the mismatched hybrid after hybridization and dissociation processes. The protein sensing abilities of the developed microsystem were also investigated through a non-competitive assay for the determination of the MB isoform of creatine kinase enzyme (CK-MB) that is a widely used cardiac marker.

  5. Microchannel neural interface manufacture by stacking silicone and metal foil laminae

    Science.gov (United States)

    Lancashire, Henry T.; Vanhoestenberghe, Anne; Pendegrass, Catherine J.; Ajam, Yazan Al; Magee, Elliot; Donaldson, Nick; Blunn, Gordon W.

    2016-06-01

    Objective. Microchannel neural interfaces (MNIs) overcome problems with recording from peripheral nerves by amplifying signals independent of node of Ranvier position. Selective recording and stimulation using an MNI requires good insulation between microchannels and a high electrode density. We propose that stacking microchannel laminae will improve selectivity over single layer MNI designs due to the increase in electrode number and an improvement in microchannel sealing. Approach. This paper describes a manufacturing method for creating MNIs which overcomes limitations on electrode connectivity and microchannel sealing. Laser cut silicone—metal foil laminae were stacked using plasma bonding to create an array of microchannels containing tripolar electrodes. Electrodes were DC etched and electrode impedance and cyclic voltammetry were tested. Main results. MNIs with 100 μm and 200 μm diameter microchannels were manufactured. High electrode density MNIs are achievable with electrodes present in every microchannel. Electrode impedances of 27.2 ± 19.8 kΩ at 1 kHz were achieved. Following two months of implantation in Lewis rat sciatic nerve, micro-fascicles were observed regenerating through the MNI microchannels. Significance. Selective MNIs with the peripheral nervous system may allow upper limb amputees to control prostheses intuitively.

  6. Zinc tin oxide as high-temperature stable recombination layer for mesoscopic perovskite/silicon monolithic tandem solar cells

    Science.gov (United States)

    Werner, Jérémie; Walter, Arnaud; Rucavado, Esteban; Moon, Soo-Jin; Sacchetto, Davide; Rienaecker, Michael; Peibst, Robby; Brendel, Rolf; Niquille, Xavier; De Wolf, Stefaan; Löper, Philipp; Morales-Masis, Monica; Nicolay, Sylvain; Niesen, Bjoern; Ballif, Christophe

    2016-12-01

    Perovskite/crystalline silicon tandem solar cells have the potential to reach efficiencies beyond those of silicon single-junction record devices. However, the high-temperature process of 500 °C needed for state-of-the-art mesoscopic perovskite cells has, so far, been limiting their implementation in monolithic tandem devices. Here, we demonstrate the applicability of zinc tin oxide as a recombination layer and show its electrical and optical stability at temperatures up to 500 °C. To prove the concept, we fabricate monolithic tandem cells with mesoscopic top cell with up to 16% efficiency. We then investigate the effect of zinc tin oxide layer thickness variation, showing a strong influence on the optical interference pattern within the tandem device. Finally, we discuss the perspective of mesoscopic perovskite cells for high-efficiency monolithic tandem solar cells.

  7. Zinc tin oxide as high-temperature stable recombination layer for mesoscopic perovskite/silicon monolithic tandem solar cells

    KAUST Repository

    Werner, Jérémie

    2016-12-05

    Perovskite/crystalline silicon tandem solar cells have the potential to reach efficiencies beyond those of silicon single-junction record devices. However, the high-temperature process of 500 °C needed for state-of-the-art mesoscopic perovskite cells has, so far, been limiting their implementation in monolithic tandem devices. Here, we demonstrate the applicability of zinc tin oxide as a recombination layer and show its electrical and optical stability at temperatures up to 500 °C. To prove the concept, we fabricate monolithic tandem cells with mesoscopic top cell with up to 16% efficiency. We then investigate the effect of zinc tin oxide layer thickness variation, showing a strong influence on the optical interference pattern within the tandem device. Finally, we discuss the perspective of mesoscopic perovskite cells for high-efficiency monolithic tandem solar cells. © 2016 Author(s)

  8. Technological and Physical Compatibilities in Hybrid Integration of Laser and Monolithic Integration of Waveguide, Photodetector and CMOS Circuits on Silicon

    NARCIS (Netherlands)

    Zhou, M.J.; Ikkink, T.; Chalmers, J.; Kranenburg, H. van; Albers, H.; Holleman, J.; Lambeck, P.V.; Joppe, J.L.; Bekman, H.H.P.T.; Krijger, A.J.T. de

    1994-01-01

    In this paper, technological and physical compatibilities in hybrid integration of AlInGaP laser and monolithic integration of ZnO monomode waveguide, pin-photodetector, CMOS circuits for laser power control and signal amplification on silicon substrate are studied. Prospective problems and their po

  9. Technological and physical compatibilities in hybrid integration of laser and monolithic integration of waveguide, photodetector and CMOS circuits on silicon

    NARCIS (Netherlands)

    Zhou, Ming-Jiang; Ikkink, Ton; Chalmers, John; Kranenburg, van Herma; Albers, Hans; Holleman, Jisk; Lambeck, Paul; Joppe, Jan Leendert; Bekman, Herman; Krijger, de Ton; Lambeck, P.V.

    1994-01-01

    In this paper, technological and physical compatibilities in hybrid integration of AlInGaP laser and monolithic integration of ZnO monomode waveguide, pin-photodetector, CMOS circuits for laser power control and signal amplification on silicon substrate are studied. Prospective problems and their po

  10. Three-dimensional (3D) monolithically integrated photodetector and WDM receiver based on bulk silicon wafer.

    Science.gov (United States)

    Song, Junfeng; Luo, Xianshu; Tu, Xiaoguang; Jia, Lianxi; Fang, Qing; Liow, Tsung-Yang; Yu, Mingbin; Lo, Guo-Qiang

    2014-08-11

    We propose a novel three-dimensional (3D) monolithic optoelectronic integration platform. Such platform integrates both electrical and photonic devices in a bulk silicon wafer, which eliminates the high-cost silicon-on-insulator (SOI) wafer and is more suitable for process requirements of electronic and photonic integrated circuits (ICs). For proof-of-concept, we demonstrate a three-dimensional photodetector and WDM receiver system. The Ge is grown on a 8-inch bulk silicon wafer while the optical waveguide is defined in a SiN layer which is deposited on top of it, with ~4 µm oxide sandwiched in between. The light is directed to the Ge photodetector from the SiN waveguide vertically by using grating coupler with a Aluminum mirror on top of it. The measured photodetector responsivity is ~0.2 A/W and the 3-dB bandwidth is ~2 GHz. Using such vertical-coupled photodetector, we demonstrated an 8-channel receiver by integrating a 1 × 8 arrayed waveguide grating (AWG). High-quality optical signal detection with up to 10 Gbit/s data rate is demonstrated, suggesting a 80 Gbit/s throughput. Such receiver can be applied to on-chip optical interconnect, DRAM interface, and telecommunication systems.

  11. A monolithic 56 Gb/s silicon photonic pulse-amplitude modulation transmitter

    CERN Document Server

    Xiong, Chi; Proesel, Jonathan E; Orcutt, Jason S; Haensch, Wilfried; Green, William M J

    2016-01-01

    Silicon photonics promises to address the challenges for next-generation short-reach optical interconnects. Growing bandwidth demand in hyper-scale data centers and high-performance computing motivates the development of faster and more-efficient silicon photonics links. While it is challenging to raise the serial line rate, further scaling of the data rate can be realized by, for example, increasing the number of parallel fibers, increasing the number of wavelengths per fiber, and using multi-level pulse-amplitude modulation (PAM). Among these approaches, PAM has a unique advantage because it does not require extra lasers or a costly overhaul of optical fiber cablings within the existing infrastructure. Here, we demonstrate the first fully monolithically integrated silicon photonic four-level PAM (PAM-4) transmitter operating at 56 Gb/s and demonstrate error-free transmission (bit-error-rate < 10$^{-12}$) up to 50 Gb/s without forward error correction. The superior PAM-4 waveform is enabled by optimizatio...

  12. Elasticity and inelasticity of silicon nitride/boron nitride fibrous monoliths.

    Energy Technology Data Exchange (ETDEWEB)

    Smirnov, B. I.; Burenkov, Yu. A.; Kardashev, B. K.; Singh, D.; Goretta, K. C.; de Arellano-Lopez, A. R.; Energy Technology; Russian Academy of Sciences; Univer. de Sevilla

    2001-01-01

    A study is reported on the effect of temperature and elastic vibration amplitude on Young's modulus E and internal friction in Si{sub 3}N{sub 4} and BN ceramic samples and Si{sub 3}N{sub 4}/BN monoliths obtained by hot pressing of BN-coated Si{sub 3}N{sub 4} fibers. The fibers were arranged along, across, or both along and across the specimen axis. The E measurements were carried out under thermal cycling within the 20-600 C range. It was found that high-modulus silicon-nitride specimens possess a high thermal stability; the E(T) dependences obtained under heating and cooling coincide well with one another. The low-modulus BN ceramic exhibits a considerable hysteresis, thus indicating evolution of the defect structure under the action of thermoelastic (internal) stresses. Monoliths demonstrate a qualitatively similar behavior (with hysteresis). This behavior of the elastic modulus is possible under microplastic deformation initiated by internal stresses. The presence of microplastic shear in all the materials studied is supported by the character of the amplitude dependences of internal friction and the Young's modulus. The experimental data obtained are discussed in terms of a model in which the temperature dependences of the elastic modulus and their features are accounted for by both microplastic deformation and nonlinear lattice-atom vibrations, which depend on internal stresses.

  13. A monolithically integrated detector-preamplifier on high-resistivity silicon

    Energy Technology Data Exchange (ETDEWEB)

    Holland, S.; Spieler, H.

    1990-02-01

    A monolithically integrated detector-preamplifier on high-resistivity silicon has been designed, fabricated and characterized. The detector is a fully depleted p-i-n diode and the preamplifier is implemented in a depletion-mode PMOS process which is compatible with detector processing. The amplifier is internally compensated and the measured gain-bandwidth product is 30 MHz with an input-referred noise of 15 nV/{radical}Hz in the white noise regime. Measurements with an Am{sup 241} radiation source yield an equivalent input noise charge of 800 electrons at 200 ns shaping time for a 1.4 mm{sup 2} detector with on-chip amplifier in an experimental setup with substantial external pickup.

  14. Sparse gallium arsenide to silicon metal waferbonding for heterogeneous monolithic microwave integrated circuits

    Science.gov (United States)

    Bickford, Justin Robert

    Waferbonding is a technique that integrates different semiconductors together, in order to obtain hybrid structures that exploit the strengths of each material. Work was done at the University of California at San Diego to investigate the waferbonding of III/V compound semiconductors to silicon using a metal interface. GaAs and other III/V compound semiconductors surpass silicon in their ability to create high performance microwave devices, while silicon offers an inexpensive platform with a proven digital architecture that can interface with microwave devices and support passive components and driver circuitry. Intimate integration of the two will be required, as mixed RF/digital and optical/digital systems for communications devices such as cell phones, wi-fi, and optical communications systems are pushed smaller, faster, and to higher power. The metalbonding implementation of a proposed heterogeneous monolithic microwave integrated circuit (HMMIC) system was investigated, and was shown to extend the capabilities of existing homogeneous monolithic microwave integrated circuit (MMIC) systems. The main goals of this work were two-fold; first to implement a robust heterogeneous integration technique, and second, to show that this approach uniquely improves upon existing microwave integration technology. The metalbonding technique investigated sparsely integrated GaAs structures onto silicon, in pursuit of this HMMIC scheme. Both bottom-up and top-down fabrication methods were implemented. These approaches required the development of a myriad of meticulously designed fabrication procedures capable of avoiding the many incompatibilities between the compound semiconductor, bondmetal, and silicon materials. The bondmetal interface, provided by these techniques, broadens the scope of existing monolithic microwave integrated circuit technology design possibilities. Essential bond interface properties were measured to establish the performance of this heterogeneous

  15. Preparation of a catalytic reactor composed of a microchannel etched on a silicon wafer; Shirikon ueha jo ni sakuseishita mikuro channeru wo mochiiru shokubai hanno sochi no shisaku

    Energy Technology Data Exchange (ETDEWEB)

    Tsubota, T.; Miyagawa, D.; Kusakabe, K.; Morooka, S. [Kyushu Univ., Fukuoka (Japan). Dept. of Applied Chemistry

    2000-11-10

    A Microchannel (upper width = 280 {mu}m, lower width = 138 {mu}m, depth 100 {mu}m, length = 27 mm) was formed on a (100) silicon wafer by means of wet chemical etching, and a platinum layer was then coated on the microchannel walls by sputtering. The resulting channel was sealed with a glass cover by an anodic bonding technique. Cyclohexane vapor, carried by a stream of nitrogen, was then introduced into the microreactor at 400 degree C, and the concentrations of both the reactant, and the products of the ensuing dehydrogenation reaction over the platinum catalyst, were determined by means of a micro gas chromatograph. Thus, a series of procedures for manufacturing and testing a microreactor such as lithography of a microchannel, the formation of a catalytic Pt film, the introduction of a reactant into the covered microchannel, or an analysis of reactants and products was established and verified. (author)

  16. Development of silicon monolithic arrays for dosimetry in external beam radiotherapy

    Energy Technology Data Exchange (ETDEWEB)

    Bisello, Francesca, E-mail: francesca.bisello@iba-group.com [IBA Dosimetry GmbH, Schwarzenbruck (Germany); Friedrich-Alexander Universität Erlangen—Nürnberg, Erlangen (Germany); Menichelli, David [IBA Dosimetry GmbH, Schwarzenbruck (Germany); Scaringella, Monica [University of Florence, Firenze (Italy); INFN—Florence Division, Sesto Fiorentino (Italy); Talamonti, Cinzia; Zani, Margherita; Bucciolini, Marta [University of Florence, Firenze (Italy); Azienda Ospedaliera Unversitaria Careggi, Firenze (Italy); Bruzzi, Mara [University of Florence, Firenze (Italy); INFN—Florence Division, Sesto Fiorentino (Italy)

    2015-10-01

    New tools for dosimetry in external beam radiotherapy have been developed during last years in the framework of the collaboration among the University of Florence, INFN Florence and IBA Dosimetry. The first step (in 2007) was the introduction in dosimetry of detector solutions adopted from high energy physics, namely epitaxial silicon as the base detector material and a guard ring in diode design. This allowed obtaining state of the art radiation hardness, in terms of sensitivity dependence on accumulated dose, with sensor geometry particularly suitable for the production of monolithic arrays with modular design. Following this study, a 2D monolithic array has been developed, based on 6.3×6.3 cm{sup 2} modules with 3 mm pixel pitch. This prototype has been widely investigated and turned out to be a promising tool to measure dose distributions of small and IMRT fields. A further linear array prototype has been recently design with improve spatial resolution (1 mm pitch) and radiation hardness. This 24 cm long device is constituted by 4×64 mm long modules. It features low sensitivity changes with dose (0.2%/kGy) and dose per pulse (±1% in the range 0.1–2.3 mGy/pulse, covering applications with flattened and unflattened photon fields). The detector has been tested with very satisfactory results as a tool for quality assurance of linear accelerators, with special regards to small fields, and proton pencil beams. In this contribution, the characterization of the linear array with unflattened MV X-rays, {sup 60}Co radiation and 226 MeV protons is reported. - Highlights: • A silicon monolithic 1D array with 1 mm pixel pitch was developed. • The detector was characterized with {sup 60}Co, unflattened MV X-rays, 226 MeV protons. • Dose linearity in clinical relevance range and dose profiles were measured. • The detector performs good agreement with reference detectors. • The technology is suitable in dose profiling in MV X-ray and proton therapy.

  17. Tailoring the graphene/silicon carbide interface for monolithic wafer-scale electronics.

    Science.gov (United States)

    Hertel, S; Waldmann, D; Jobst, J; Albert, A; Albrecht, M; Reshanov, S; Schöner, A; Krieger, M; Weber, H B

    2012-07-17

    Graphene is an outstanding electronic material, predicted to have a role in post-silicon electronics. However, owing to the absence of an electronic bandgap, graphene switching devices with high on/off ratio are still lacking. Here in the search for a comprehensive concept for wafer-scale graphene electronics, we present a monolithic transistor that uses the entire material system epitaxial graphene on silicon carbide (0001). This system consists of the graphene layer with its vanishing energy gap, the underlying semiconductor and their common interface. The graphene/semiconductor interfaces are tailor-made for ohmic as well as for Schottky contacts side-by-side on the same chip. We demonstrate normally on and normally off operation of a single transistor with on/off ratios exceeding 10(4) and no damping at megahertz frequencies. In its simplest realization, the fabrication process requires only one lithography step to build transistors, diodes, resistors and eventually integrated circuits without the need of metallic interconnects.

  18. Spatial characterization of monolithic multi-element Silicon-Drift-Detectors for X-ray spectroscopic applications

    CERN Document Server

    Kappen, P; Hansen, K; Reckleben, C; Lechner, P; Strüder, L; Materlik, G

    2001-01-01

    Spatially resolved spectroscopic measurements with a 10 and 20 mu m pencil beam have been performed on a monolithic 7-element Silicon-Drift-Detector (SDD). Detailed studies are shown of the modification of the spectroscopic response at pixel edges and pixel centre. The results give quantitative insight into the local SDD performance. A simple model predicts global properties (e.g. peak-to-background ratio) of larger SDD arrays, like the 61-element detector currently under development.

  19. Fabrication of open-top microchannel plate using deep X-ray exposure mask made with silicon on insulator substrate

    CERN Document Server

    Fujimura, T; Etoh, S I; Hattori, R; Kuroki, Y; Chang, S S

    2003-01-01

    We propose a high-aspect-ratio open-top microchannel plate structure. This type of microchannel plate has many advantages in electrophoresis. The plate was fabricated by deep X-ray lithography using synchrotron radiation (SR) light and the chemical wet etching process. A deep X-ray exposure mask was fabricated with a silicon on insulator (SOI) substrate. The patterned Si microstructure was micromachined into a thin Si membrane and a thick Au X-ray absorber was embedded in it by electroplating. A plastic material, polymethylmethacrylate (PMMA) was used for the plate substrate. For reduction of the exposure time and high-aspect-ratio fast wet development, the fabrication condition was optimized with respect to not the exposure dose but to the PMMA mean molecular weight (M.W.) changing after deep X-ray exposure as measured by gel permeation chromatography (GPC). Decrement of the PMMA M.W. and increment of the wet developer temperature accelerated the etching rate. Under optimized fabrication conditions, a microc...

  20. GaAs-based nanoneedle light emitting diode and avalanche photodiode monolithically integrated on a silicon substrate.

    Science.gov (United States)

    Chuang, Linus C; Sedgwick, Forrest G; Chen, Roger; Ko, Wai Son; Moewe, Michael; Ng, Kar Wei; Tran, Thai-Truong D; Chang-Hasnain, Connie

    2011-02-09

    Monolithic integration of III-V compound semiconductor devices with silicon CMOS integrated circuits has been hindered by large lattice mismatches and incompatible processing due to high III-V epitaxy temperatures. We report the first GaAs-based avalanche photodiodes (APDs) and light emitting diodes, directly grown on silicon at a very low, CMOS-compatible temperature and fabricated using conventional microfabrication techniques. The APDs exhibit an extraordinarily large multiplication factor at low voltage resulting from the unique needle shape and growth mode.

  1. Fabrication and Characterization of Silicon Micro-Funnels and Tapered Micro-Channels for Stochastic Sensing Applications

    Directory of Open Access Journals (Sweden)

    Frances S. Ligler

    2008-06-01

    Full Text Available We present a simplified, highly reproducible process to fabricate arrays of tapered silicon micro-funnels and micro-channels using a single lithographic step with a silicon oxide (SiO2 hard mask on at a wafer scale. Two approaches were used for the fabrication. The first one involves a single wet anisotropic etch step in concentrated potassium hydroxide (KOH and the second one is a combined approach comprising Deep Reactive Ion Etch (DRIE followed by wet anisotropic etching. The etching is performed through a 500 mm thick silicon wafer, and the resulting structures are characterized by sharp tapered ends with a sub-micron cross-sectional area at the tip. We discuss the influence of various parameters involved in the fabrication such as the size and thickness variability of the substrate, dry and wet anisotropic etching conditions, the etchant composition, temperature, diffusion and micro-masking effects, the quality of the hard mask in the uniformity and reproducibility of the structures, and the importance of a complete removal of debris and precipitates. The presence of apertures at the tip of the structures is corroborated through current voltage measurements and by the translocation of DNA through the apertures. The relevance of the results obtained in this report is discussed in terms of the potential use of these structures for stochastic sensing.

  2. AIN Monolithic Microchannel Cooled Heatsink for High Power Laser Diode Array%应用于大功率激光二极管列阵的单片集成微通道制冷热沉

    Institute of Scientific and Technical Information of China (English)

    马杰慧; 方高瞻; 蓝永生; 马骁宇

    2005-01-01

    介绍了一种应用于大功率激光二极管列阵的新型单片集成微通道制冷热沉.这种热沉已制造并经过测试.10叠层的激光二极管列阵的热阻为0.121℃/W.相邻两个激光条的间距是1.17mm.在20%高占空比条件下,波长为808nm左右,峰值功率可以达到611W.%A novel AIN monolithic microchannel cooled heatsink for high power laser diode array is introduced.The high power stack laser diode array with an AIN monolithic microchannel heatsink is fabricated and tested.The thermal impedance of a 10 stack laser diode array is 0.121℃/W.The pitch between two adjacent bars is 1.17mm.The power level of 611W is achieved under the 20% duty factor condition at an emission wavelength around 808nm.

  3. Laser Soldering and Thermal Cycling Tests of Monolithic Silicon Pixel Chips

    CERN Document Server

    Strand, Frode Sneve

    2015-01-01

    An ALPIDE-1 monolithic silicon pixel sensor prototype has been laser soldered to a flex printed circuit using a novel interconnection technique using lasers. This technique is to be optimised to ensure stable, good quality connections between the sensor chips and the FPCs. To test the long-term stability of the connections, as well as study the effects on hit thresholds and noise in the sensor, it was thermally cycled in a climate chamber 1200 times. The soldered connections showed good qualities like even melting and good adhesion on pad/flex surfaces, and the chip remained in working condition for 1080 cycles. After this, a few connections failed, having cracks in the soldering tin, rendering the chip unusable. Threshold and noise characteristics seemed stable, except for the noise levels of sector 2 in the chip, for 1000 cycles in a temperature interval of "10^{\\circ}" and "50^{\\circ}" C. Still, further testing with wider temperature ranges and more cycles is needed to test the limitations of the chi...

  4. Matrix cracking and creep behavior of monolithic zircon and zircon silicon carbide fiber composites

    Science.gov (United States)

    Anandakumar, Umashankar

    In this study, the first matrix cracking behavior and creep behavior of zircon matrix silicon carbide fiber composites were studied, together with the fracture and creep behavior of the monolithic zircon. These behaviors are of engineering and scientific importance, and the study was aimed at understanding the deformation mechanisms at elevated temperatures. The first matrix cracking behavior of zircon matrix uniaxially reinforced with silicon carbide fiber (SCS-6) composites and failure behavior of monolithic zircon were studied as a function of temperature (25°C, 500°C, and 1200°C) and crack length in three point bending mode. A modified vicker's indentation technique was used to vary the initial crack length in monolithic and composite samples. The interfacial shear strength was measured at these temperatures from matrix crack saturation spacing. The composites exhibited steady state and non steady state behaviors at the three different temperatures as predicted by theoretical models, while the failure stress of zircon decreased with increasing stress. The intrinsic properties of the composites were used to numerically determine the results predicted by three different matrix cracking models based on a fracture mechanics approach. The analysis showed that the model based on crack bridging analysis was valid at 25°C and 500°C, while a model based on statistical fiber failure was valid at 1200°C. Microstructural studies showed that fiber failure in the crack wake occurred at or below the matrix cracking stress at 1200°C, and no fiber failure occurred at the other two temperatures, which validated the results predicted by the theoretical models. Also, it was shown that the interfacial shear stress corresponding to debonding determined the matrix cracking stress, and not the frictional shear stress. This study showed for the first time, the steady state and non-steady state matrix cracking behavior at elevated temperatures, the difference in behavior between

  5. A Monolithically Integrated Gallium Nitride Nanowire/Silicon Solar Cell Photocathode for Selective Carbon Dioxide Reduction to Methane.

    Science.gov (United States)

    Wang, Yichen; Fan, Shizhao; AlOtaibi, Bandar; Wang, Yongjie; Li, Lu; Mi, Zetian

    2016-06-20

    A gallium nitride nanowire/silicon solar cell photocathode for the photoreduction of carbon dioxide (CO2 ) is demonstrated. Such a monolithically integrated nanowire/solar cell photocathode offers several unique advantages, including the absorption of a large part of the solar spectrum and highly efficient carrier extraction. With the incorporation of copper as the co-catalyst, the devices exhibit a Faradaic efficiency of about 19 % for the 8e(-) photoreduction to CH4 at -1.4 V vs Ag/AgCl, a value that is more than thirty times higher than that for the 2e(-) reduced CO (ca. 0.6 %).

  6. Optimal Design of Silicon-based Chips for Piezo-induced Ultrasound Resonances in Embedded Microchannels

    DEFF Research Database (Denmark)

    Garofalo, F.; Laurell, T.; Bruus, Henrik

    2015-01-01

    of the Lagrangian density leads to the derivation of the correct structure of the Hamiltonian density, i.e. the energy density, which is important for the quantification of the energy content of the whole system and its individual parts. Specifically, the energy content of the embedded microchannel is quantified......We present a variational formulation of the governing equations and introduce global indicators to describe the behavior of acoustofluidic devices driven at resonance frequencies by means of a piezoelectric transducer. The individuation of the correct Lagrangian densities for the different parts.......e. the lateral motion of particle dragged by the axial main flow, is particularly strong. Finally, the connection between the mechanical and electrical degrees of freedom of the system is addressed. This is important for proper determination of the dissipated power, and it may lead to the detection of resonance...

  7. Image Shutters: Gated Proximity-Focused Microchannel-Plate (MCP) Wafer Tubes Versus Gated Silicon Intensified Target (SIT) Vidicons

    Science.gov (United States)

    Yates, G. J.; King, N. S. P.; Jaramillo, S. A.; Ogle, J. W.; Noel, B. W.; Thayer, N. N.

    1983-03-01

    The imaging characteristics of two fast image shutters used for recording the spatial and temporal evolution of transient optical events in the nanosecond range have been studied. Emphasis is on the comparative performances of each shutter type under similar conditions. Response data, including gating speed, gain, dynamic range, shuttering efficiency, and resolution for 18 and 25-mm-diam proximity-focused microchannel-plate (MCP) intensifiers are com-pared with similar data for a prototype electrostatically-focused 25-mm-diam gated silicon-intensified-target (SIT) vidicon currently under development for Los Alamos National Laboratory. Several key parameters critical to optical gating speed have been varied in both tube types in order to determine the optimum performance attainable from each design. These include conductive substrate material and thickness used to reduce photocathode resistivity, spacing between gating electrodes to minimize interelectrode capacitance, the use of con-ductive grids on the photocathode substrate to permit rapid propagation of the electrical gate pulse to all areas of the photocathode, and different package geometries to provide a more effective interface with external biasing and gating circuitry. For comparable spatial resolution, most 18-mm-diam MCPs require gate times > 2.5 ns while the fastest SIT has demonstrated sub-nanosecond optical gates as short as r 400 ± 50 ps for full shuttering of the 25-mm-diam input window.

  8. Image shutters: Gated proximity-focused Microchannel Plate (MCP) wafer tubes versus gated Silicon Intensified Target (SIT) vidicons

    Science.gov (United States)

    Yates, G. J.; King, N. S. P.; Jaramillo, S. A.; Ogle, J. W.; Noel, B. W.; Thayer, N. N.

    Response data, including gating speed, gain, dynamic range, shuttering efficiency, and resolution for 18- and 25-mm-diam proximity-focused microchannel-plate (MCP) intensifiers are compared with similar data for a prototype electrostatically-focused 25-mm-diam gated silicon-intensified-target (SIT) vidicon. Conductive substrate material and thickness used to reduce photocathode resistivity, spacing between gating electrodes to minimize inter-electrode capacitance, the use of conductive grids on the photocathode substrate to permit rapid propagation of the electrical gate pulse to all areas of the photocathode, and different package geometries to provide a more effective interface with external biasing and gating circuitry were varied in both tube types to determine optimal performance from each design. For comparable spatial resolution, most 18-mm-diam MCPs require gate times 2.5 ns while the fastest SIT has demonstrated sub-nanosecond optical gates as short as approximately 400 + or - 50 ps for full shuttering of the 25-mm-diam input window.

  9. Microchannel cooling in low material budget supports for silicon pixel detectors

    Energy Technology Data Exchange (ETDEWEB)

    Balestri, G. [INFN Pisa, Largo B. Pontecorvo 3, 56010 Pisa (Italy); Bosi, F., E-mail: filippo.bosi@pi.infn.i [INFN Pisa, Largo B. Pontecorvo 3, 56010 Pisa (Italy); Ceccanti, M.; Mammini, P.; Massa, M.; Petragnani, G.; Ragonesi, A.; Soldani, A. [INFN Pisa, Largo B. Pontecorvo 3, 56010 Pisa (Italy)

    2010-05-21

    Pixel detectors at future colliders will need to match very stringent requirement on position resolution. To ensure the needed mechanical stability and the removal of the power dissipated by the read-out electronic, the support structure and cooling add an important contribution to the total material in the active area, in terms of radiation length. We present the development, the construction and the mechanical-thermal characterization of prototypes of light material support for pixel detectors with microchannel for heat evacuation through forced convection of liquid coolant. The solution we choose shows several advantages: heat exchange is taking place efficiently due to the high ratio surface/volume and so high thermal conductivities can be obtained, minimally affecting the stiffness of the structure; the thermal resistances are reduced because of the contiguity between the fluid and the circuit dissipating power; the uniformity of temperature on the surface covered by of the sensors is also kept under control. Several prototypes implementing different geometries of micro-machined channels have been realized in composites materials (CFRP). FEA studies have been performed to validated the experimental test conducted in the thermo-fluid dynamic test bench we recently assembled in the INFN Pisa laboratory.

  10. Monolithic Integration of a Novel Microfluidic Device with Silicon Light Emitting Diode-Antifuse and Photodetector

    NARCIS (Netherlands)

    LeMinh, P.; Holleman, J.; Berenschot, J.W.; Tas, N.R.; Berg, van den A.

    2002-01-01

    Light emitting diode antifuse has been integrated into a microfluidic device that is realized with extended standard CMOS technological steps. The device comprises of a microchannel sandwiched between a photodiode detector and a nanometer-scale diode antifuse light emitter. Within this contribution,

  11. 硅基正弦波纹微通道内的流动阻力特性%Flow friction in silicon-based sinusoidal wavy microchannels

    Institute of Scientific and Technical Information of China (English)

    张弛; 吴慧英; 黄后学

    2012-01-01

    硅基正弦波纹微通道在微尺度强化换热、微流体器件中均有重要运用,而目前尚未见有关于其内部流动特性的实验报道.利用标准微机电系统(MEMS)工艺在硅基芯片上加工制成一系列具有不同相位差和周期、当量直径为160μm的正弦波纹微通道,通过实验研究了其内部流动阻力特性.研究表明:正弦波纹微通道较平直微通道阻力均有增加,且增加幅度与波纹微通道两侧壁的相位差和周期有关.对于周期相同的波纹微通道,两侧壁相位差越大,阻力也越大.对于相位差相同的波纹微通道,周期对阻力的影响则较为复杂:当相位差为0时,呈现出周期越大、阻力越小的趋势(除最小周期通道外);当相位差为π时,呈现出周期越大、阻力越大的趋势.研究还发现:随着周期减小,相位差对阻力的影响减小,当周期缩短至0.5 mm时,相位差为0和π的波纹微通道内的阻力特性曲线几乎重合.%A series of sinusoidal wavy microchannels with different phase shifts and wavelengths were fabricated on the silicon wafer based on the MEMS technology. Flow frictions in these sinusoidal wavy microchannels were investigated experimentally. Results show that the flow friction in wavy microchannels is higher compared with the smooth straight microchannels with the same hydraulic diameter. Both the phase shift and the wavelength have effect on the flow friction in wavy microchannels. For the microchannels with the same wavelength, the flow friction increases as the phase shift increases. However, the influence of wavelength is complicated. For the microchannels with phase shift of 0, the flow friction normally increases as the wavelength decreases with the exception for the microchannel with the smallest wavelength. For the microchannels with phase shift of 7t, the flow friction decreases as the wavelength decreases due to the decrease of the throat size in the microchannels. The investigation

  12. Monolithic silicon photonics in a sub-100nm SOI CMOS microprocessor foundry: progress from devices to systems

    Science.gov (United States)

    Popović, Miloš A.; Wade, Mark T.; Orcutt, Jason S.; Shainline, Jeffrey M.; Sun, Chen; Georgas, Michael; Moss, Benjamin; Kumar, Rajesh; Alloatti, Luca; Pavanello, Fabio; Chen, Yu-Hsin; Nammari, Kareem; Notaros, Jelena; Atabaki, Amir; Leu, Jonathan; Stojanović, Vladimir; Ram, Rajeev J.

    2015-02-01

    We review recent progress of an effort led by the Stojanović (UC Berkeley), Ram (MIT) and Popović (CU Boulder) research groups to enable the design of photonic devices, and complete on-chip electro-optic systems and interfaces, directly in standard microelectronics CMOS processes in a microprocessor foundry, with no in-foundry process modifications. This approach allows tight and large-scale monolithic integration of silicon photonics with state-of-the-art (sub-100nm-node) microelectronics, here a 45nm SOI CMOS process. It enables natural scale-up to manufacturing, and rapid advances in device design due to process repeatability. The initial driver application was addressing the processor-to-memory communication energy bottleneck. Device results include 5Gbps modulators based on an interleaved junction that take advantage of the high resolution of the sub-100nm CMOS process. We demonstrate operation at 5fJ/bit with 1.5dB insertion loss and 8dB extinction ratio. We also demonstrate the first infrared detectors in a zero-change CMOS process, using absorption in transistor source/drain SiGe stressors. Subsystems described include the first monolithically integrated electronic-photonic transmitter on chip (modulator+driver) with 20-70fJ/bit wall plug energy/bit (2-3.5Gbps), to our knowledge the lowest transmitter energy demonstrated to date. We also demonstrate native-process infrared receivers at 220fJ/bit (5Gbps). These are encouraging signs for the prospects of monolithic electronics-photonics integration. Beyond processor-to-memory interconnects, our approach to photonics as a "More-than- Moore" technology inside advanced CMOS promises to enable VLSI electronic-photonic chip platforms tailored to a vast array of emerging applications, from optical and acoustic sensing, high-speed signal processing, RF and optical metrology and clocks, through to analog computation and quantum technology.

  13. Monolithic LaBr₃:Ce crystals on silicon photomultiplier arrays for time-of-flight positron emission tomography.

    Science.gov (United States)

    Seifert, Stefan; van Dam, Herman T; Huizenga, Jan; Vinke, Ruud; Dendooven, Peter; Löhner, Herbert; Schaart, Dennis R

    2012-04-21

    Positron emission tomography detectors based on monolithic scintillation crystals exhibit good spatial and energy resolution, intrinsically provide depth-of-interaction information, have high γ-photon capture efficiency, and may reduce the manufacturing costs compared to pixelated crystal arrays. Here, we present the characterization of a detector consisting of a 18.0 mm×16.2 mm×10.0 mm monolithic LaBr₃:5%Ce scintillator directly coupled to a 4×4 array of silicon photomultipliers. An energy resolution of 6.4% full-width-at-half-maximum (FWHM) was obtained. The point-spread-function (PSF) was determined for different regions of the detector. The full-width-at-half-maximum (FWHM) of the PSF was measured to be <1.5 mm at the center of the detector and <1.7 mm averaged over the entire crystal. Both values are not corrected for the ~0.6 mm FWHM test beam diameter. Furthermore, the influence of edge effects was investigated. We found that near the edges of the detector the spatial resolution degrades to 2.2 mm (FWHM), and a bias in the position estimates, up to 1.5 mm, was observed. Moreover, the coincidence resolving time for two identical detectors in coincidence was measured to be as small as ~198 ps FWHM.

  14. Two-axis MEMS scanner with transfer-printed high-reflectivity, broadband monolithic silicon photonic crystal mirrors.

    Science.gov (United States)

    Jeong, Jae-Woong; Park, Bryan; Keum, Hohyun; Kim, Seok; Rogers, John A; Solgaard, Olav

    2013-06-03

    We present a two-axis electrostatic MEMS scanner with high-reflectivity monolithic single-crystal-silicon photonic crystal (PC) mirrors suitable for applications in harsh environments. The reflective surfaces of the MEMS scanner are transfer-printed PC mirrors with low polarization dependence, low angular dependence, and reflectivity over 85% in the wavelength range of 1490nm~1505nm and above 90% over the wavelength band of 1550~1570nm. In static mode, the scanner has total scan range of 10.2° on one rotation axis and 7.8° on the other. Dynamic operation on resonance increase the scan range to 21° at 608Hz around the outer rotation axis and 9.5° at 1.73kHz about the inner rotation axis.

  15. Monolithic nanoscale photonics-electronics integration in silicon and other group IV elements

    CERN Document Server

    Radamson, Henry

    2014-01-01

    Silicon technology is evolving rapidly, particularly in board-to-board or chip-to chip applications. Increasingly, the electronic parts of silicon technology will carry out the data processing, while the photonic parts take care of the data communication. For the first time, this book describes the merging of photonics and electronics in silicon and other group IV elements. It presents the challenges, the limitations, and the upcoming possibilities of these developments. The book describes the evolution of CMOS integrated electronics, status and development, and the fundamentals of silicon p

  16. A linear monolithic 4-6 on silicon IR detector array

    Science.gov (United States)

    Vandamme, J.; Vermeiren, J.; Zogg, H.; Masek, J.; Fabbricotti, M.

    1992-12-01

    A linear array of monolithically grown PbTe and PbSnSe detectors on (111)-Si for MWIR and TIR imaging applications was designed and processed. The array consists of a staggered row of 2 by 128 detectors on a 100 micrometers pitch. The readout circuitry, integrated on the Si substrate consists of a COS multiplexer with a direct injection input stage, a charge reduction stage and charge to voltage conversion stage for each individual detector. This XDI (MultipeXed Direct Injection) circuit also allows for on-chip nonuniformity compensation with a switched capacitor network.

  17. Research on high-efficiency, single-junction, monolithic, thin-film amorphous silicon solar cells

    Science.gov (United States)

    Wiesmann, H.; Dolan, J.; Fricano, G.; Danginis, V.

    1987-02-01

    A study was undertaken of the optoelectronic properties of amorphous silicon-hydrogen thin films deposited from disilane at high deposition rates. The information derived from this study was used to fabricate amorphous silicon solar cells with efficiencies exceeding 7%. The intrinsic layer of these solar cells was deposited at 15 angstroms/second. Material properties investigated included dark conductivity, photoconductivity, minority carrier diffusion length, and density of states. The solar cells properties characterized were absolute quantum yield and simulated global AM 1.5 efficiencies. Investigations were undertaken utilizing optical and infrared spectroscopy to optimize the microstructures of the intrinsic amorphous silicon. That work was sponsored by the New York State Energy Research and Development Authority. The information was used to optimize the intrinsic layer of amorphous silicon solar cells, resulting in AM 1.5 efficiencies exceeding 7%.

  18. High-speed detection at two micrometres with monolithic silicon photodiodes

    Science.gov (United States)

    Ackert, Jason J.; Thomson, David J.; Shen, Li; Peacock, Anna C.; Jessop, Paul E.; Reed, Graham T.; Mashanovich, Goran Z.; Knights, Andrew P.

    2015-06-01

    With continued steep growth in the volume of data transmitted over optical networks there is a widely recognized need for more sophisticated photonics technologies to forestall a ‘capacity crunch’. A promising solution is to open new spectral regions at wavelengths near 2 μm and to exploit the long-wavelength transmission and amplification capabilities of hollow-core photonic-bandgap fibres and the recently available thulium-doped fibre amplifiers. To date, photodetector devices for this window have largely relied on III-V materials or, where the benefits of integration with silicon photonics are sought, GeSn alloys, which have been demonstrated thus far with only limited utility. Here, we describe a silicon photodiode operating at 20 Gbit s-1 in this wavelength region. The detector is compatible with standard silicon processing and is integrated directly with silicon-on-insulator waveguides, which suggests future utility in silicon-based mid-infrared integrated optics for applications in communications.

  19. Probing Photocurrent Nonuniformities in the Subcells of Monolithic Perovskite/Silicon Tandem Solar Cells

    KAUST Repository

    Song, Zhaoning

    2016-11-23

    Perovskite/silicon tandem solar cells with high power conversion efficiencies have the potential to become a commercially viable photovoltaic option in the near future. However, device design and optimization is challenging because conventional characterization methods do not give clear feedback on the localized chemical and physical factors that limit performance within individual subcells, especially when stability and degradation is a concern. In this study, we use light beam induced current (LBIC) to probe photocurrent collection nonuniformities in the individual subcells of perovskite/silicon tandems. The choices of lasers and light biasing conditions allow efficiency-limiting effects relating to processing defects, optical interference within the individual cells, and the evolution of water-induced device degradation to be spatially resolved. The results reveal several types of microscopic defects and demonstrate that eliminating these and managing the optical properties within the multilayer structures will be important for future optimization of perovskite/silicon tandem solar cells.

  20. Probing Photocurrent Nonuniformities in the Subcells of Monolithic Perovskite/Silicon Tandem Solar Cells.

    Science.gov (United States)

    Song, Zhaoning; Werner, Jérémie; Shrestha, Niraj; Sahli, Florent; De Wolf, Stefaan; Niesen, Björn; Watthage, Suneth C; Phillips, Adam B; Ballif, Christophe; Ellingson, Randy J; Heben, Michael J

    2016-12-15

    Perovskite/silicon tandem solar cells with high power conversion efficiencies have the potential to become a commercially viable photovoltaic option in the near future. However, device design and optimization is challenging because conventional characterization methods do not give clear feedback on the localized chemical and physical factors that limit performance within individual subcells, especially when stability and degradation is a concern. In this study, we use light beam induced current (LBIC) to probe photocurrent collection nonuniformities in the individual subcells of perovskite/silicon tandems. The choices of lasers and light biasing conditions allow efficiency-limiting effects relating to processing defects, optical interference within the individual cells, and the evolution of water-induced device degradation to be spatially resolved. The results reveal several types of microscopic defects and demonstrate that eliminating these and managing the optical properties within the multilayer structures will be important for future optimization of perovskite/silicon tandem solar cells.

  1. Monolithic integration of detectors and transistors on high-resistivity silicon

    Energy Technology Data Exchange (ETDEWEB)

    Dalla Betta, Gian-Franco [INFN, Sezione di Padova (Gruppo Collegato Trento), and Universita di Trento, Via Sommarive 14, 38050 Povo (Trento) (Italy)], E-mail: dallabe@dit.unitn.it; Batignani, Giovanni [INFN, Sezione di Pisa, and Universita di Pisa, Largo B. Pontecorvo 3, 56127 Pisa (Italy); Boscardin, Maurizio [ITC-irst, Divisione Microsistemi, Via Sommarive 18, 38050 Povo (Trento) (Italy); Bosisio, Luciano [INFN, Sezione di Trieste, and Universita di Trieste, Via A. Valerio 2, 34127 Trieste (Italy); Gregori, Paolo; Pancheri, Lucio; Piemonte, Claudio [ITC-irst, Divisione Microsistemi, Via Sommarive 18, 38050 Povo (Trento) (Italy); Ratti, Lodovico [INFN, Sezione di Pavia, and Universita di Pavia, Via Ferrata 1, 27100 Pavia (Italy); Verzellesi, Giovanni [INFN, Sezione di Padova (Gruppo Collegato Trento), and Universita di Modena e Reggio Emilia, Via Vignolese 905, 42100 Modena (Italy); Zorzi, Nicola [ITC-irst, Divisione Microsistemi, Via Sommarive 18, 38050 Povo (Trento) (Italy)

    2007-09-01

    We report on the most recent results from an R and D activity aimed at the development of silicon radiation detectors with embedded front-end electronics. The key features of the fabrication technology and the available active devices are described. Selected results from the characterization of transistors and test structures are presented and discussed, and the considered application fields are addressed.

  2. Imaging and chemical surface analysis of biomolecular functionalization of monolithically integrated on silicon Mach-Zehnder interferometric immunosensors

    Energy Technology Data Exchange (ETDEWEB)

    Gajos, Katarzyna, E-mail: kasia.fornal@uj.edu.pl [M. Smoluchowski Institute of Physics, Jagiellonian University, Łojasiewicza 11, 30-348 Kraków (Poland); Angelopoulou, Michailia; Petrou, Panagiota [Institute of Nuclear & Radiological Sciences & Technology, Energy & Safety, NCSR Demokritos, P. Grigoriou & Neapoleos St, Aghia Paraksevi 15310, Athens (Greece); Awsiuk, Kamil [M. Smoluchowski Institute of Physics, Jagiellonian University, Łojasiewicza 11, 30-348 Kraków (Poland); Kakabakos, Sotirios [Institute of Nuclear & Radiological Sciences & Technology, Energy & Safety, NCSR Demokritos, P. Grigoriou & Neapoleos St, Aghia Paraksevi 15310, Athens (Greece); Haasnoot, Willem [RIKILT Wageningen UR, Akkermaalsbos 2, 6708 WB Wageningen (Netherlands); Bernasik, Andrzej [Faculty of Physics and Applied Computer Science, AGH University of Science and Technology, Mickiewicza 30, 30-059 Kraków (Poland); Academic Centre for Materials and Nanotechnology, AGH University of Science and Technology, Mickiewicza 30, 30-059 Kraków (Poland); Rysz, Jakub [M. Smoluchowski Institute of Physics, Jagiellonian University, Łojasiewicza 11, 30-348 Kraków (Poland); Marzec, Mateusz M. [Academic Centre for Materials and Nanotechnology, AGH University of Science and Technology, Mickiewicza 30, 30-059 Kraków (Poland); Misiakos, Konstantinos; Raptis, Ioannis [Department of Microelectronics, Institute of Nanoscience and Nanotechnology, NCSR Demokritos, P. Grigoriou & Neapoleos St, Aghia Paraksevi 15310, Athens (Greece); Budkowski, Andrzej [M. Smoluchowski Institute of Physics, Jagiellonian University, Łojasiewicza 11, 30-348 Kraków (Poland)

    2016-11-01

    Highlights: • Optimization of probe immobilization with robotic spotter printing overlapping spots. • In-situ inspection of microstructured surfaces of biosensors integrated on silicon. • Imaging and chemical analysis of immobilization, surface blocking and immunoreaction. • Insight with molecular discrimination into step-by-step sensor surface modifications. • Optimized biofunctionalization improves sensor sensitivity and response repeatability. - Abstract: Time-of-flight secondary ion mass spectrometry (imaging, micro-analysis) has been employed to evaluate biofunctionalization of the sensing arm areas of Mach-Zehnder interferometers monolithically integrated on silicon chips for the immunochemical (competitive) detection of bovine κ-casein in goat milk. Biosensor surfaces are examined after: modification with (3-aminopropyl)triethoxysilane, application of multiple overlapping spots of κ-casein solutions, blocking with 100-times diluted goat milk, and reaction with monoclonal mouse anti-κ-casein antibodies in blocking solution. The areas spotted with κ-casein solutions of different concentrations are examined and optimum concentration providing homogeneous coverage is determined. Coverage of biosensor surfaces with biomolecules after each of the sequential steps employed in immunodetection is also evaluated with TOF-SIMS, supplemented by Atomic force microscopy and X-ray photoelectron spectroscopy. Uniform molecular distributions are observed on the sensing arm areas after spotting with optimum κ-casein concentration, blocking and immunoreaction. The corresponding biomolecular compositions are determined with a Principal Component Analysis that distinguished between protein amino acids and milk glycerides, as well as between amino acids characteristic for Mabs and κ-casein, respectively. Use of the optimum conditions (κ-casein concentration) for functionalization of chips with arrays of ten Mach-Zehnder interferometers provided on-chips assays

  3. The upgrade of the ALICE Inner Tracking System - Status of the R&D; on monolithic silicon pixel sensors

    CERN Document Server

    Van Hoorne, Jacobus Willem

    2014-01-01

    s a major part of its upgrade plans, the ALICE experiment schedules the installation of a novel Inner Tracking System (ITS) during the Long Shutdown 2 (LS2) of the LHC in 2018/19. It will replace the present silicon tracker with seven layers of Monolithic Active Pixel Sensors (MAPS) and significantly improve the detector performance in terms of tracking and rate capabilities. The choice of technology has been guided by the tight requirements on the material budget of 0 : 3 % X = X 0 /layer for the three innermost layers and backed by the significant progress in the field of MAPS in recent years. The pixel chips are manufactured in the TowerJazz 180 nm CMOS imaging sensor process on wafers with a high resistivity epitaxial layer. Within the ongoing R&D; phase, several sensor chip prototypes have been developed and produced on different epitaxial layer thicknesses and resistivities. These chips are being characterized for their performance before and after irradiation using source tests, test beam and measu...

  4. Imaging and chemical surface analysis of biomolecular functionalization of monolithically integrated on silicon Mach-Zehnder interferometric immunosensors

    Science.gov (United States)

    Gajos, Katarzyna; Angelopoulou, Michailia; Petrou, Panagiota; Awsiuk, Kamil; Kakabakos, Sotirios; Haasnoot, Willem; Bernasik, Andrzej; Rysz, Jakub; Marzec, Mateusz M.; Misiakos, Konstantinos; Raptis, Ioannis; Budkowski, Andrzej

    2016-11-01

    Time-of-flight secondary ion mass spectrometry (imaging, micro-analysis) has been employed to evaluate biofunctionalization of the sensing arm areas of Mach-Zehnder interferometers monolithically integrated on silicon chips for the immunochemical (competitive) detection of bovine κ-casein in goat milk. Biosensor surfaces are examined after: modification with (3-aminopropyl)triethoxysilane, application of multiple overlapping spots of κ-casein solutions, blocking with 100-times diluted goat milk, and reaction with monoclonal mouse anti-κ-casein antibodies in blocking solution. The areas spotted with κ-casein solutions of different concentrations are examined and optimum concentration providing homogeneous coverage is determined. Coverage of biosensor surfaces with biomolecules after each of the sequential steps employed in immunodetection is also evaluated with TOF-SIMS, supplemented by Atomic force microscopy and X-ray photoelectron spectroscopy. Uniform molecular distributions are observed on the sensing arm areas after spotting with optimum κ-casein concentration, blocking and immunoreaction. The corresponding biomolecular compositions are determined with a Principal Component Analysis that distinguished between protein amino acids and milk glycerides, as well as between amino acids characteristic for Mabs and κ-casein, respectively. Use of the optimum conditions (κ-casein concentration) for functionalization of chips with arrays of ten Mach-Zehnder interferometers provided on-chips assays with dramatically improved both intra-chip response repeatability and assay detection sensitivity.

  5. Low-noise monolithic bipolar front-end for silicon drift detectors

    Science.gov (United States)

    Dabrowski, W.; Bialas, W.; Bonazzola, G.; Bonvicini, W.; Casati, L.; Ceretto, F.; Giubellino, P.; Prest, M.; Riccati, L.; Zampa, N.

    1999-01-01

    A very low noise, 32-channel preamplifier/shaper chip has been designed for the analogue readout of silicon detectors. The circuit has been optimized in view of the operation of silicon drift detectors, which have very low capacitance and produce gaussian signals of σ of few tens of ns. The chip (OLA) has been designed and manufactured using the SHPi full-custom bipolar process by Tektronix. Each channel is composed by a preamplifier, a shaper and a symmetrical line driver, which allows to drive either a positive and a negative single ended output separately on 50 Ω impedance or a differential twisted pair. The intrinsic peaking time of the circuit is ˜60 ns, and the noise is below 250 electrons at zero input load capacitance. The power consumption is 2 mW/channel, mostly due to the output driver.

  6. Surface Structure Enhanced Microchannel Flow Boiling

    OpenAIRE

    Zhu, Yangying; Antao, Dion Savio; Chu, Kuang-Han; Chen, Siyu; Hendricks, Terry J.; Zhang, Tiejun; Wang, Evelyn N.

    2016-01-01

    We investigated the role of surface microstructures in two-phase microchannels on suppressing flow instabilities and enhancing heat transfer. We designed and fabricated microchannels with well-defined silicon micropillar arrays on the bottom heated microchannel wall to promote capillary flow for thin film evaporation while facilitating nucleation only from the sidewalls. Our experimental results show significantly reduced temperature and pressure drop fluctuation especially at high heat fluxe...

  7. Microchannel heat sink assembly

    Science.gov (United States)

    Bonde, Wayne L.; Contolini, Robert J.

    1992-01-01

    The present invention provides a microchannel heat sink with a thermal range from cryogenic temperatures to several hundred degrees centigrade. The heat sink can be used with a variety of fluids, such as cryogenic or corrosive fluids, and can be operated at a high pressure. The heat sink comprises a microchannel layer preferably formed of silicon, and a manifold layer preferably formed of glass. The manifold layer comprises an inlet groove and outlet groove which define an inlet manifold and an outlet manifold. The inlet manifold delivers coolant to the inlet section of the microchannels, and the outlet manifold receives coolant from the outlet section of the microchannels. In one embodiment, the manifold layer comprises an inlet hole extending through the manifold layer to the inlet manifold, and an outlet hole extending through the manifold layer to the outlet manifold. Coolant is supplied to the heat sink through a conduit assembly connected to the heat sink. A resilient seal, such as a gasket or an O-ring, is disposed between the conduit and the hole in the heat sink in order to provide a watetight seal. In other embodiments, the conduit assembly may comprise a metal tube which is connected to the heat sink by a soft solder. In still other embodiments, the heat sink may comprise inlet and outlet nipples. The present invention has application in supercomputers, integrated circuits and other electronic devices, and is suitable for cooling materials to superconducting temperatures.

  8. Model development of monolithic tandem silicon-perovskite solar cell by SCAPS simulation

    Science.gov (United States)

    Ramli, Noor Fadhilah; Sepeai, Suhaila; Rostan, Nur Fairuz Mohd; Ludin, Norasikin Ahmad; Ibrahim, Mohd. Adib; Teridi, Mohd Asri Mat; Zaidi, Salem H.

    2017-05-01

    Organic-inorganic lead halide perovskites have significant role in the photovoltaic (PV) technology due to its high efficiency, lightweight and cost effectiveness especially methyl ammonium lead (II) iodide (MALI). The MALI can act as absorber layer which has a band gap of 1.5 eV which is compatible to be paired with silicon (Si) solar cell with energy gap of 1.124 eV as a tandem solar cell. This tandem approach is an refined solution to improve the efficiency of Si solar cell that has been stuck around 25 % for 15 years. This study focuses on the development of the device configuration model for Si-perovskite tandem solar cell by using SCAPS simulation. The thickness and dopant concentration of perovskite layer have affected the solar cell parameters performance. The efficiency result obtained from SCAPS simulation is 27.29 % for Si-perovskite tandem solar cell with an open circuit voltage of 0.8178 V, short circuit current 43.55 mA/cm2 and fill factor 76.61 %.

  9. A Monolithic Radiation-Pressure Driven, Low Phase Noise Silicon Nitride Opto-Mechanical Oscillator

    CERN Document Server

    Tallur, Siddharth; Bhave, Sunil A

    2011-01-01

    Cavity opto-mechanics enabled radiation pressure (RP) driven oscillators shown in the past offer an all optical Radio Frequency (RF) source without the need for external electrical feedback. However these oscillators require external tapered fiber or prism coupling and non-standard fabrication processes. In this work, we present a CMOS compatible fabrication process to design high optical quality factor opto-mechanical resonators in silicon nitride. The ring resonators designed in this process demonstrate low phase noise RP driven oscillations. Using integrated grating couplers and waveguide to couple light to the micro-resonator eliminates 1/f^3 and other higher order phase noise slopes at close-to-carrier frequencies present in previous demonstrations. We present an RP driven OMO operating at 41.97MHz with a signal power of -11dBm and phase noise of -85dBc/Hz at 1kHz offset with only 1/f^2 noise down to 10Hz offset from carrier.

  10. Monolithic LaBr3 : Ce crystals on silicon photomultiplier arrays for time-of-flight positron emission tomography

    NARCIS (Netherlands)

    Seifert, Stefan; van Dam, Herman T.; Huizenga, Jan; Vinke, Ruud; Dendooven, Peter; Löhner, Herbert; Schaart, Dennis R.

    2012-01-01

    Positron emission tomography detectors based on monolithic scintillation crystals exhibit good spatial and energy resolution, intrinsically provide depth-of-interaction information, have high gamma-photon capture efficiency, and may reduce the manufacturing costs compared to pixelated crystal

  11. Monolithic LaBr3 : Ce crystals on silicon photomultiplier arrays for time-of-flight positron emission tomography

    NARCIS (Netherlands)

    Seifert, Stefan; van Dam, Herman T.; Huizenga, Jan; Vinke, Ruud; Dendooven, Peter; Löhner, Herbert; Schaart, Dennis R.

    2012-01-01

    Positron emission tomography detectors based on monolithic scintillation crystals exhibit good spatial and energy resolution, intrinsically provide depth-of-interaction information, have high gamma-photon capture efficiency, and may reduce the manufacturing costs compared to pixelated crystal arrays

  12. Development of large-area monolithically integrated silicon-film{trademark} photovoltaic modules. Final subcontract report, May 1, 1991--December 31, 1994

    Energy Technology Data Exchange (ETDEWEB)

    Hall, R.B.; Rand, J.A.; Cotter, J.E. [AstroPower, Inc., Newark, DE (United States)

    1995-04-01

    The objective of this program is to develop Silicon Film{trademark} Product III into a low-cost, stable solar cell for large-scale terrestrial power applications. The Product III structure is a thin (<100 {mu}m) polycrystalline layer of silicon on a durable, insulating, ceramic substrate. The insulating substrate allows the silicon layer to be isolated and metallized to form a monolithically interconnected array of solar cells. High efficiency is achieved by the use of light trapping and passivated surfaces. This project focused on the development of five key technologies associated with the monolithic sub-module device structure: (1) development of the film deposition and growth processes; (2) development of the low-cost ceramic substrate; (3) development of a metallurgical barrier technology; (4) development of sub-element solar cell processing techniques; and (5) development of sub-module (isolation and interconnection) processes. This report covers the development approaches and results relating to these technologies. Significant progress has been made in the development of all of the related technologies. This is evidenced by the fabrication of a working 12.0 cm{sup 2} prototype sub-module consisting of 7 elements and testing with an open circuit voltage of 3.9 volts, a short circuit current of 35.2 mA and a fill factor of 63% and an overall efficiency of 7.3%. Another significant result achieved is a 13.4% (NREL verified), 1.0 cm{sup 2} solar cell fabricated from material deposited and grown on a graphite cloth substrate. The significant technological hurdle of the program was and remains the low quality of the photovoltaic layer which is caused by contamination of the photovoltaic layer from the low-cost ceramic substrate by trace impurities found in the substrate precursor materials. The ceramic substrate and metallurgical barrier are being developed specifically to solve this problem.

  13. A 16 GHz silicon-based monolithic balanced photodetector with on-chip capacitors for 25 Gbaud front-end receivers.

    Science.gov (United States)

    Hai, Mohammed Shafiqul; Sakib, Meer Nazmus; Liboiron-Ladouceur, Odile

    2013-12-30

    In this paper, a Germanium-on-Silicon balanced photodetector (BPD) with integrated biasing capacitors is demonstrated for highly compact monolithic 100 Gb/s coherent receivers or 25 Gbaud front-end receivers for differential or quadrature phase shift keying. The balanced photodetector has a bandwidth of approximately 16.2 GHz at a reverse bias of -4.5 V. The balanced photodetector exhibits a common mode rejection ratio (CMRR) of 30 dB. For balanced detection of return-to-zero (RZ) differential phase shift keying (DPSK) signal, the photodetector has a sensitivity of -6.95 dBm at the BER of 10(-12). For non-return-to-zero (NRZ) on off keying (OOK) signal, the measured BER is 1.0 × 10(-12) for a received power of -1.65 dBm at 25 Gb/s and 9.9 × 10(-5) for -0.34 dBm at 30 Gb/s. The total footprint area of the monolithic front-end receiver is less than 1 mm(2). The BPD is packaged onto a ceramic substrate with two DC and one RF connectors exhibits a bandwidth of 15.9 GHz.

  14. Monolithic multinozzle emitters for nanoelectrospray mass spectrometry

    Science.gov (United States)

    Wang, Daojing; Yang, Peidong; Kim, Woong; Fan, Rong

    2011-09-20

    Novel and significantly simplified procedures for fabrication of fully integrated nanoelectrospray emitters have been described. For nanofabricated monolithic multinozzle emitters (NM.sup.2 emitters), a bottom up approach using silicon nanowires on a silicon sliver is used. For microfabricated monolithic multinozzle emitters (M.sup.3 emitters), a top down approach using MEMS techniques on silicon wafers is used. The emitters have performance comparable to that of commercially-available silica capillary emitters for nanoelectrospray mass spectrometry.

  15. Monolithic integration of a silicon nanowire field-effect transistors array on a complementary metal-oxide semiconductor chip for biochemical sensor applications.

    Science.gov (United States)

    Livi, Paolo; Kwiat, Moria; Shadmani, Amir; Pevzner, Alexander; Navarra, Giulio; Rothe, Jörg; Stettler, Alexander; Chen, Yihui; Patolsky, Fernando; Hierlemann, Andreas

    2015-10-06

    We present a monolithic complementary metal-oxide semiconductor (CMOS)-based sensor system comprising an array of silicon nanowire field-effect transistors (FETs) and the signal-conditioning circuitry on the same chip. The silicon nanowires were fabricated by chemical vapor deposition methods and then transferred to the CMOS chip, where Ti/Pd/Ti contacts had been patterned via e-beam lithography. The on-chip circuitry measures the current flowing through each nanowire FET upon applying a constant source-drain voltage. The analog signal is digitized on chip and then transmitted to a receiving unit. The system has been successfully fabricated and tested by acquiring I-V curves of the bare nanowire-based FETs. Furthermore, the sensing capabilities of the complete system have been demonstrated by recording current changes upon nanowire exposure to solutions of different pHs, as well as by detecting different concentrations of Troponin T biomarkers (cTnT) through antibody-functionalized nanowire FETs.

  16. SU-E-T-163: Characterization of a Novel High Resolution 1D Silicon Monolithic Array for Small Field Commissioning and Quality Assurance

    Energy Technology Data Exchange (ETDEWEB)

    Bisello, F [FAU University Erlangen-Nuernberg, Erlangen, DE (Germany); IBA Dosimetry, Schwarzenbruck, DE (United States); McGlade, J; Wang, P; Kralik, J; Kosterin, P; Mooij, R; Solberg, T [University of Pennsylvenia, Philadelphia, PA (United States); Menichelli, D; Celi, J [IBA Dosimetry, Schwarzenbruck, DE (United States)

    2015-06-15

    Purpose: To study the suitability of a novel 1D silicon monolithic array for dosimetry of small radiation fields and for QA of high dose gradient treatment modalities (IMRT and SBRT). Methods: A 1D array composed of 4 monolithic silicon modules of 64 mm length and 1 mm pixel pitch was developed by IBA Dosimetry. Measurements were carried out for 6MV and 15MV photons on two commercial different linacs (TrueBeam and Clinac iX, Varian Medical Systems, Palo Alto, CA) and for a CyberKnife G4 (Accuray Inc., Sunnyvale, CA). The 1D array was used to measure output factors (OF), profiles and off axis correction factors (OACF) for the Iris CyberKnife variable collimator (5–60 mm). In addition, dose profiles (at the isocenter plane) were measured for multiple IMRT and SBRT treatment plans and compared with those obtained using EDR2radiographic film (Carestream Health, Rochester NY), a commercial 2D diode array and with the dose distribution calculated using a commercial TPS (Eclipse, Varian Medical Systems, Palo Alto, CA). Results: Due to the small pixel pitch of the detector, IMRT and SBRT plan profiles deviate from film measurements by less than 2%. Similarly, the 1D array exhibits better performance than the 2D diode array due to the larger (7 mm) pitch of that device. Iris collimator OFs measured using the 1D silicon array are in good agreement with the commissioning values obtained using a commercial stereotactic diode as well as with published data. Maximum deviations are < 3% for the smallest field (5 and 7.5mm) and below 1% for all other dimensions. Conclusion: We have demonstrated good performances of the array for commissioning of small photon fields and in patient QA, compared with diodes and film typically used in these clinical applications. The technology compares favorably with existing commercial solutions The presenting author is founded by a Marie Curie Early Initial Training Network Fellowship of the European Communitys Seventh Framework Programme under

  17. Heat and mass transfer in a square microchannel with asymmetric heating

    NARCIS (Netherlands)

    Male, van P.; Croon, de M.H.J.M.; Tiggelaar, R.M.; Berg, van den A.; Schouten, J.C.

    2004-01-01

    This paper describes the heat and mass transfer in a square microchannel that is heated from one side. This microchannel represents a reaction channel in a microreactor that is used to study the kinetics of the catalytic partial oxidation of methane. The microchannel is contained in a silicon wafer

  18. Unravelling a simple method for the low temperature synthesis of silicon nanocrystals and monolithic nanocrystalline thin films

    Science.gov (United States)

    Kim, Ka-Hyun; Johnson, Erik V.; Kazanskii, Andrey G.; Khenkin, Mark V.; Roca I Cabarrocas, Pere

    2017-01-01

    In this work, we present new results on the plasma processing and structure of hydrogenated polymorphous silicon (pm-Si:H) thin films. pm-Si:H thin films consist of a low volume fraction of silicon nanocrystals embedded in a silicon matrix with medium range order, and they possess this morphology as a significant contribution to their growth comes from the impact on the substrate of silicon clusters and nanocrystals synthesized in the plasma. Quadrupole mass spectrometry, ion flux measurements, and material characterization by transmission electron microscopy (TEM) and atomic force microscopy all provide insight on the contribution to the growth by silicon nanocrystals during PECVD deposition. In particular, cross-section TEM measurements show for the first time that the silicon nanocrystals are uniformly distributed across the thickness of the pm-Si:H film. Moreover, parametric studies indicate that the best pm-Si:H material is obtained at the conditions after the transition between a pristine plasma and one containing nanocrystals, namely a total gas pressure around 2 Torr and a silane to hydrogen ratio between 0.05 to 0.1. From a practical point of view these conditions also correspond to the highest deposition rate achievable for a given RF power and silane flow rate.

  19. Unravelling a simple method for the low temperature synthesis of silicon nanocrystals and monolithic nanocrystalline thin films

    Science.gov (United States)

    Kim, Ka-Hyun; Johnson, Erik V.; Kazanskii, Andrey G.; Khenkin, Mark V.; Roca i Cabarrocas, Pere

    2017-01-01

    In this work, we present new results on the plasma processing and structure of hydrogenated polymorphous silicon (pm-Si:H) thin films. pm-Si:H thin films consist of a low volume fraction of silicon nanocrystals embedded in a silicon matrix with medium range order, and they possess this morphology as a significant contribution to their growth comes from the impact on the substrate of silicon clusters and nanocrystals synthesized in the plasma. Quadrupole mass spectrometry, ion flux measurements, and material characterization by transmission electron microscopy (TEM) and atomic force microscopy all provide insight on the contribution to the growth by silicon nanocrystals during PECVD deposition. In particular, cross-section TEM measurements show for the first time that the silicon nanocrystals are uniformly distributed across the thickness of the pm-Si:H film. Moreover, parametric studies indicate that the best pm-Si:H material is obtained at the conditions after the transition between a pristine plasma and one containing nanocrystals, namely a total gas pressure around 2 Torr and a silane to hydrogen ratio between 0.05 to 0.1. From a practical point of view these conditions also correspond to the highest deposition rate achievable for a given RF power and silane flow rate. PMID:28091562

  20. Adhesion of microchannel-based complementary surfaces.

    Science.gov (United States)

    Singh, Arun K; Bai, Ying; Nadermann, Nichole; Jagota, Anand; Hui, Chung-Yuen

    2012-03-06

    We show that highly enhanced and selective adhesion can be achieved between surfaces patterned with complementary microchannel structures. An elastic material, poly(dimethylsiloxane) (PDMS), was used to fabricate such surfaces by molding into a silicon master with microchannel profiles patterned by photolithography. We carried out adhesion tests on both complementary and mismatched microchannel/micropillar surfaces. Adhesion, as measured by the energy release rate required to propagate an interfacial crack, can be enhanced by up to 40 times by complementary interfaces, compared to a flat control, and slightly enhanced for some special noncomplementary samples, despite the nearly negligible adhesion for other mismatched surfaces. For each complementary surface, we observe defects in the form of visible striations, where pillars fail to insert fully into the channels. The adhesion between complementary microchannel surfaces is enhanced by a combination of a crack-trapping mechanism and friction between a pillar and channel and is attenuated by the presence of defects.

  1. Monolithic Composite Electrodes Comprising Silicon Nanoparticles Embedded in Lignin-derived Carbon Fibers for Lithium-Ion Batteries

    Energy Technology Data Exchange (ETDEWEB)

    Rios, Orlando [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Martha, Surendra K. [Indian Inst. of Technology (IIT), Yedduaram (India); McGuire, Michael A. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Tenhaeff, Wyatt [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); More, Karren [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Daniel, Claus [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Nanda, Jagjit [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2014-08-26

    Here, we report direct manufacturing of high-capacity carbon/silicon composite fiber electrodes for lithium-ion batteries produced via a flexible low-cost melt processing route, yielding low-cost stable silicon particles coated in situ by a 10 nanometer thick protective silica layer. Moreover, the core–shell silicon/SiO2 islands are embedded in electrochemically active and electronically conductive carbon fiber derived from lignin precursor material. The silicon–silica–carbon composites exhibit capacities exceeding 700 mAh g-1 with Coulombic efficiencies in excess of 99.5 %. Finally, the high efficiency, stability, and rate capability are linked to the nanocrystalline structure and abundant, uniform nanometer-thick SiO2 interfaces that are produced during the spinning and subsequent pyrolysis of the precursor blend.

  2. Quasi monolithic silicon load cell for loads up to 1000 kg with insensitivity to non-homogeneous load distributions

    NARCIS (Netherlands)

    Wiegerink, Remco; Zwijze, Robert; Krijnen, Gijs; Lammerink, Theo; Elwenspoek, Miko

    2000-01-01

    In this paper, a micromachined silicon load cell (force sensor) is presented for measuring loads up to 1000 kg. The sensitive surface of 1 cm2 contains a matrix of capacitive sensing elements to make the load cell insensitive to non-homogeneous load distributions. The load cell has been realized and

  3. Silicon Light: a European FP7 project aiming at high efficiency thin film silicon solar cells on foil. Monolithic series interconnection of flexible thin-film PV devices

    Energy Technology Data Exchange (ETDEWEB)

    Soppe, W. [ECN Solar Energy, P.O. Box 1, 1755 ZG Petten (Netherlands); Haug, F.J. [Ecole Polytechnique Federale de Lausanne EPFL, Photovoltaics and Thin Film Electronics Laboratory, Rue A.-L. Breguet 2, 2000 Neuchatel (Switzerland); Couty, P. [VHFTechnologies SA, Rue Edouard-Verdan 2, CH-1400 Yverdon-les-Bains (Switzerland); Duchamp, M. [Technical University of Denmark, Center for Electron Nanoscopy, DK-2800 Kongens Lyngby (Denmark); Schipper, W. [Nanoptics GmbH, Innungstr.5, 21244 Buchholz (Germany); Krc, J. [University of Ljubljana, Faculty of Electrical Engineering, Trzaska 25, SI-1000 Ljubljana (Slovenia); Sanchez, G. [Universidad Politecnica de Valencia, I.U.I. Centro de Tecnologia Nanofotonica, 46022 Valencia (Spain); Leitner, K. [Umicore Thin Film Products AG, Balzers (Liechtenstein); Wang, Q. [Shanghai Jiaotong University, Research Institute of Micro/Nanometer Science and Technology, 800 Dongchuan Road, Min Hang, 200240 Shanghai (China)

    2011-09-15

    Silicon-Light is a European FP7 project, which started January 1st, 2010 and aims at development of low cost, high-efficiency thin film silicon solar cells on foil. Three main routes are explored to achieve these goals: (a) advanced light trapping by implementing nanotexturization through UV Nano Imprinting Lithography (UV-NIL); (b) growth of crack-free silicon absorber layers on highly textured substrates; (c) development of new TCOs which should combine the best properties of presently available materials like ITO and AZO. The paper presents the midterm status of the project results, showing model calculations of ideal nanotextures for light trapping in thin film silicon solar cells; the fabrication of masters and the replication and roll-to-roll fabrication of these nanotextures. Further, results on ITO variants with improved work function are presented. Finally, the status of cell fabrication on foils with nanotexture is shown. Microcrystalline and amorphous silicon single junction cells with stable efficiencies with more than 8% have been made, paving the way towards a-Si/{mu}c-Si tandem cells with more than 11% efficiency.

  4. HOT EMBOSSING METHODS FOR PLASTIC MICROCHANNEL FABRICATION

    Institute of Scientific and Technical Information of China (English)

    LIU Junshan; WANG Liding; LIU Chong; LUO Yi

    2006-01-01

    Fabrication of microchannels on polymethylmethacrylate (PMMA) substrates using novel microfabrication methods is demonstrated. The image of microchannels is transferred from a silicon master possessing the inverse image of the microchannel to a PMMA plate by using hot embossing methods. The silicon master is electrostatically bonded to a Pyrex 7740 glass wafer, which improves the device yield from about 20 devices to hundreds of devices per master. Effects of embossing temperature, pressure and time on the accuracy of replication are systematically studied using the orthogonal factorial design. According to the suggested experimental model, the time for the whole embossing procedure is shorten from about 20 min to 6 min, and the accuracy of replication is 99.3%.The reproducibility of the hot embossing method is evaluated using 10 channels on different microfluidic devices, with variations of 1.4 % in depth and 1.8% in width.

  5. A wafer-scale packaging structure with monolithic microwave integrated circuits and passives embedded in a silicon substrate for multichip modules for radio frequency applications

    Science.gov (United States)

    Geng, Fei; Ding, Xiao-yun; Xu, Gao-wei; Luo, Le

    2009-10-01

    A wafer-level packaging structure with chips and passive components embedded in a silicon substrate for multichip modules (MCM) is proposed for radio frequency (RF) applications. The packaging structure consists of two layers of benzocyclobutene (BCB) films and three layers of metalized films, in which the monolithic microwave ICs (MMICs), thin film resistors, striplines and microstrip lines are integrated. The low resistivity silicon wafer with etched cavities is used as a substrate. The BCB films serve as interlayer dielectrics (ILDs). Wirebonding gold bumps are used as electric interconnections between different layers, which eliminate the need of preparing vias by costly procedures including dry etching, metal sputtering and electroplating. The chemical mechanical planarization (CMP) is used to uncover the gold bumps, and the BCB curing profile is optimized to obtain the appropriate BCB film for CMP process. In this work, the thermal, mechanical, electrical as well as RF properties of the packaging structure are investigated. The packaging thermal resistance can be controlled below 2 °C W-1. The average shear strength of the gold bumps on the BCB surface is about 70 MPa. In addition, a Kelvin test structure is fabricated for resistance testing of the vertical vias. The performances of MMIC and interconnection structure at high frequency are simulated and tested. The testing results reveal that the slight shifting of S-parameter curves of the packaged MMIC indicates perfect transmission characteristics at high frequency. For the transition structure of transmission line, the experimental results are compatible with the simulation results. The insertion loss (S21) is below 0.4 dB from 0 to 40 GHz and the return loss (S11) is less than -20 dB from 0 to 40 GHz. For a low noise amplifier (LNA) chip, the S21 shifting caused by the packaging structure is below 0.5 dB, and S11 is less than -10 dB from 8 GHz to 14 GHz.

  6. Silicon photomultiplier readout of a monolithic 270$\\times$5$\\times$5 cm$^3$ plastic scintillator bar for time of flight applications

    CERN Document Server

    Reinhardt, Tobias P; Reinicke, Stefan; Bemmerer, Daniel; Cowan, Thomas E; Heidel, Klaus; Röder, Marko; Stach, Daniel; Wagner, Andreas; Weinberger, David; Zuber, Kai

    2016-01-01

    The detection of 200-1000 MeV neutrons requires large amounts, $\\sim$100 cm, of detector material because of the long nuclear interaction length of these particles. In the example of the NeuLAND neutron time-of-flight detector at FAIR, this is accomplished by using 3000 monolithic scintillator bars of 270$\\times$5$\\times$5 cm$^3$ size made of a fast plastic. Each bar is read out on the two long ends, and the needed time resolution of $\\sigma_t$ $<$ 150 ps is reached with fast timing photomultipliers. In the present work, it is investigated whether silicon photomultiplier (SiPM) photosensors can be used instead. Experiments with a picosecond laser system were conducted to determine the timing response of the assembly made up of SiPM and preamplifier. The response of the full system including also the scintillator was studied using 30 MeV single electrons provided by the ELBE superconducting electron linac. The ELBE data were matched by a simple Monte Carlo simulation, and they were found to obey an inverse-...

  7. Hydrogen-terminated mesoporous silicon monoliths with huge surface area as alternative Si-based visible light-active photocatalysts

    KAUST Repository

    Li, Ting

    2016-07-21

    Silicon-based nanostructures and their related composites have drawn tremendous research interest in solar energy storage and conversion. Mesoporous silicon with a huge surface area of 400-900 m2 g-1 developed by electrochemical etching exhibits excellent photocatalytic ability and stability after 10 cycles in degrading methyl orange under visible light irradiation, owing to its unique mesoporous network, abundant surface hydrides and efficient light harvesting. This work showcases the profound effects of surface area, crystallinity, pore topology on charge migration/recombination and mass transportation. Therein the ordered 1D channel array has outperformed the interconnected 3D porous network by greatly accelerating the mass diffusion and enhancing the accessibility of the active sites on the extensive surfaces. © 2016 The Royal Society of Chemistry.

  8. Performance of a monolithic LaBr{sub 3}:Ce crystal coupled to an array of silicon photomultipliers

    Energy Technology Data Exchange (ETDEWEB)

    Ulyanov, Alexei, E-mail: alexey.uliyanov@ucd.ie [School of Physics, University College Dublin, Belfield, Dublin 4 (Ireland); Morris, Oran [School of Physics, University College Dublin, Belfield, Dublin 4 (Ireland); Department of Computer Science & Applied Physics, Galway-Mayo Institute of Technology, Galway (Ireland); Hanlon, Lorraine; McBreen, Sheila; Foley, Suzanne; Roberts, Oliver J.; Tobin, Isaac; Murphy, David; Wade, Colin [School of Physics, University College Dublin, Belfield, Dublin 4 (Ireland); Nelms, Nick; Shortt, Brian [European Space Agency, ESTEC, 2200 AG Noordwijk (Netherlands); Slavicek, Tomas; Granja, Carlos; Solar, Michael [Institute of Experimental and Applied Physics, Czech Technical University in Prague, 12800 Prague 2 (Czech Republic)

    2016-02-21

    A gamma-ray detector composed of a single 28×28×20 mm{sup 3} LaBr{sub 3}:Ce crystal coupled to a custom built 4×4 array of silicon photomultipliers was tested over an energy range of 30 keV to 9.3 MeV. The silicon photomultipliers were initially calibrated using 20 ns light pulses generated by a light emitting diode. The photodetector responses measured as a function of the number of incident photons were found to be non-linear and consistent with model predictions. Using corrections for the non-linearity of the silicon photomultipliers, the detector showed a linear response to gamma-rays with energies from 100 keV to the maximum available energy of 9.3 MeV. The energy resolution was found to be 4% FWHM at 662 keV. Despite the large thickness of the scintillator (20 mm) and a 5 mm thick optical window, the detector was capable of measuring the positions of the gamma-ray interaction points. The position resolution was measured at 356 keV and was found to be 8 mm FWHM in the detector plane and 11 mm FWHM for the depth of interaction. The detector can be used as a building block of a larger calorimeter system that is capable of measuring gamma-ray energies up to tens of MeV.

  9. Monolithic spectrometer

    Science.gov (United States)

    Rajic, Slobodan; Egert, Charles M.; Kahl, William K.; Snyder, Jr., William B.; Evans, III, Boyd M.; Marlar, Troy A.; Cunningham, Joseph P.

    1998-01-01

    A monolithic spectrometer is disclosed for use in spectroscopy. The spectrometer is a single body of translucent material with positioned surfaces for the transmission, reflection and spectral analysis of light rays.

  10. Robotic Tactile Sensors Fabricated from a Monolithic Silicon Integrated Circuit and a Piezoelectric Polyvinylidene Fluoride Thin Film

    Science.gov (United States)

    1991-12-01

    quartz crystals has been in the communications industry , where the crystals were used in very selective band-pass filters in lbroad-bland carrier...PVDF on .Silicon Integrated Circuit."* Sensors and A4ctuators, 27:. 167-172 (191). 86. Park, 1K. and others. "’A PVDF Tactile Sensor for Industrial ...G. E. Neville. -Jr. "The Induced Vibration Touch Sensor - A New Dynamic Touch Sensing Systemn," Robotica , 4: 27-31 (1986). 88. Paul. C. R. and S. A

  11. Microchannel Reactors for ISRU Applications

    Science.gov (United States)

    Carranza, Susana; Makel, Darby B.; Blizman, Brandon; Ward, Benjamin J.

    2005-02-01

    Affordable planning and execution of prolonged manned space missions depend upon the utilization of local resources and the waste products which are formed in manned spacecraft and surface bases. Successful in-situ resources utilization (ISRU) will require component technologies which provide optimal size, weight, volume, and power efficiency. Microchannel reactors enable the efficient chemical processing of in situ resources. The reactors can be designed for the processes that generate the most benefit for each mission. For instance, propellants (methane) can be produced from carbon dioxide from the Mars atmosphere using the Sabatier reaction and ethylene can be produced from the partial oxidation of methane. A system that synthesizes ethylene could be the precursor for systems to synthesize ethanol and polyethylene. Ethanol can be used as a nutrient for Astrobiology experiments, as well as the production of nutrients for human crew (e.g. sugars). Polyethylene can be used in the construction of habitats, tools, and replacement parts. This paper will present recent developments in miniature chemical reactors using advanced Micro Electro Mechanical Systems (MEMS) and microchannel technology to support ISRU of Mars and lunar missions. Among other applications, the technology has been demonstrated for the Sabatier process and for the partial oxidation of methane. Microchannel reactors were developed based on ceramic substrates as well as metal substrates. In both types of reactors, multiple layers coated with catalytic material are bonded, forming a monolithic structure. Such reactors are readily scalable with the incorporation of extra layers. In addition, this reactor structure minimizes pressure drop and catalyst settling, which are common problems in conventional packed bed reactors.

  12. Heat transfer and fluid flow in microchannels

    Science.gov (United States)

    Mala, Ghulam Mohiuddin

    Fluid flow and heat transfer characteristics in microchannels of different cross-sections; parallel plate, cylindrical and trapezoidal microchannels were studied. The trapezoidal microchannels were etched in silicon and glass by photolithographic techniques. The cylindrical microchannels of fused silica and stainless steel were readily available. Channels with depths of 18 μm to 300 μm were studied. The study was divided into three parts viz. theoretical modeling, numerical simulation and experimentation. Electrokinetic effects such as the effects of electrical double layer (EDL) at the solid-liquid interface and surface roughness effects were considered. An experimental apparatus was constructed and a procedure devised to measure the flow rate, pressure drop, temperatures and electrokinetic parameters like streaming potential, streaming current, and conductivity of the working fluid. Great care was taken so that the measurements were accurate and repeatable. For steady state laminar flow and heat transfer in microchannels, mathematical models were developed that consider the effects of electrical double layer and surface roughness at the microchannel walls. The non- linear, 2-D, Poisson-Boltzmann equation that describes the potential distribution at the solid liquid interface was solved numerically and results were compared with a linear approximate solution that overestimates the potential distribution for higher values of zeta potential. Effects of the EDL field at the solid-liquid interface, surface roughness at the microchannel walls and the channel size, on the velocity distribution, streaming potential, apparent viscosity, temperature distribution and heat transfer characteristics are discussed. The experimental results indicate significant departure in flow characteristics from the predictions of the Navier-Stokes equations, referred to as conventional theory. The difference between the experimental results and theoretical predictions decreases as the

  13. Photovoltaic manufacturing technology monolithic amorphous silicon modules on continuous polymer substrates: Final technical report, July 5, 1995--December 31, 1999

    Energy Technology Data Exchange (ETDEWEB)

    Jeffrey, F.

    2000-03-28

    Iowa Thin Film Technologies is completing a three-phase program that has increased throughput and decreased costs in nearly all aspects of its thin-film photovoltaic manufacturing process. The overall manufacturing costs have been reduced by 61 percent through implementation of the improvements developed under this program. Development of the ability to use a 1-mil substrate, rather than the standard 2-mil substrate, results in a 50 percent cost-saving for this material. Process development on a single-pass amorphous silicon deposition system has resulted in a 37 percent throughput improvement. A wide range of process and machine improvements have been implemented on the transparent conducting oxide deposition system. These include detailed parameter optimization of deposition temperatures, process gas flows, carrier gas flows, and web speeds. An overall process throughput improvement of 275 percent was achieved based on this work. The new alignment technique was developed for the laser scriber and printer systems, which improved registration accuracy from 100 microns to 10 microns. The new technique also reduced alignment time for these registration systems significantly. This resulted in a throughput increase of 75 percent on the scriber and 600 percent on the printer. Automated techniques were designed and implemented for the module assembly processes. These include automated busbar attachment, roll-based lamination, and automated die cutting of finished modules. These processes were previously done by hand labor. Throughput improvements ranged from 200 percent to 1200 percent, relative to hand labor rates. A wide range of potential encapsulation materials were evaluated for suitability in a roll lamination process and for cost-effectiveness. A combination material was found that has a cost that is only 10 percent of the standard EVA/Tefzel cost and is suitable for medium-lifetime applications. The 20-year lifetime applications still require the more expensive

  14. Droplets Fusion in a Microchannel on a Piezoelectric Substrate

    OpenAIRE

    Fu Xiang-ting; Zha Yan; Zhang An-liang

    2013-01-01

    Fusion droplets is a key operation in a microfluidic device for microfluidic analysis. A new fusion method for droplets was presented. An interditigal transducer and a reflector were fabricated on 1280-yx LiNbO3 piezoelectric substrate using microelectric technology. A poly-dimethyl silicone micro-channel was made by soft lithography technology and mounted on the piezoelectric substrate. Droplets in the microchannel were actuated by surface acoustic wave and fussed each other. Coloured dye so...

  15. Fabrication of nanocomposite electrode based on Bi{sub 4−x}Nd{sub x}Ti{sub 3}O{sub 12} perovskite supported by silicon microchannel plates for high performance electrochemical capacitors

    Energy Technology Data Exchange (ETDEWEB)

    Miao, Fengjuan [College of Communications and Electronics Engineering, Qiqihar University, Heilongjiang 161006 (China); National Laboratory for Infrared Physics, Shanghai Institute of Technical Physics, Chinese Academy of Sciences, Shanghai 200083 (China); Tao, Bairui, E-mail: tbr_sir@163.com [College of Communications and Electronics Engineering, Qiqihar University, Heilongjiang 161006 (China); National Laboratory for Infrared Physics, Shanghai Institute of Technical Physics, Chinese Academy of Sciences, Shanghai 200083 (China); Computer Center, Qiqihar University, Heilongjiang 161006 (China); Chu, Paul K. [Department of Physics and Materials Sciences, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong (China)

    2015-01-15

    Highlights: • Bi{sub 4−x}Nd{sub x}Ti{sub 3}O{sub 12}/Ni/Si-MCP is an excellent electrode for electrochemical capacitors. • The electrodes provide large specific surface areas. • This research may provide a meaning way in integratable electrochemical capacitors. - Abstract: A novel self-standing Bi{sub 4−x}Nd{sub x}Ti{sub 3}O{sub 12} electrodes structure based on the three dimensional silicon microchannel plates (Si-MCP) is proposed for electrochemical capacitors. In order to decrease electron transfer barrier and contact resistance, the Ni/Si-MCP compound materials were synthesized as current collectors by electroless plating. The Bi{sub 4−x}Nd{sub x}Ti{sub 3}O{sub 12} perovskite were distributed on the channel of Ni/Si-MCP compound structure by sol–gel techniques. The morphology and microstructure of as-synthesized mesoporous Bi{sub 4−x}Nd{sub x}Ti{sub 3}O{sub 12} (BNT) were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD). The electrodes have not only excellent capacitive performances, but also superior electrochemical stability. Owing to the formation of thin film morphology, porous structure, ordered channel and the intimate contact between the electroactive material and the current collector, the BNT/Ni/Si-MCP electrodes provide an enhancement of the kinetics by short transport/diffusion path lengths, timely accompanying of electrolyte and large specific surface areas, thus both high energy density and high power density are achieved. In particular, since the fabrication process is compatible with conventional silicon technology, the structure has immense potential as integrated supercapacitors.

  16. Active microchannel heat exchanger

    Science.gov (United States)

    Tonkovich, Anna Lee Y [Pasco, WA; Roberts, Gary L [West Richland, WA; Call, Charles J [Pasco, WA; Wegeng, Robert S [Richland, WA; Wang, Yong [Richland, WA

    2001-01-01

    The present invention is an active microchannel heat exchanger with an active heat source and with microchannel architecture. The microchannel heat exchanger has (a) an exothermic reaction chamber; (b) an exhaust chamber; and (c) a heat exchanger chamber in thermal contact with the exhaust chamber, wherein (d) heat from the exothermic reaction chamber is convected by an exothermic reaction exhaust through the exhaust chamber and by conduction through a containment wall to the working fluid in the heat exchanger chamber thereby raising a temperature of the working fluid. The invention is particularly useful as a liquid fuel vaporizer and/or a steam generator for fuel cell power systems, and as a heat source for sustaining endothermic chemical reactions and initiating exothermic reactions.

  17. Monoliths in Bioprocess Technology

    Directory of Open Access Journals (Sweden)

    Vignesh Rajamanickam

    2015-04-01

    Full Text Available Monolithic columns are a special type of chromatography column, which can be used for the purification of different biomolecules. They have become popular due to their high mass transfer properties and short purification times. Several articles have already discussed monolith manufacturing, as well as monolith characteristics. In contrast, this review focuses on the applied aspect of monoliths and discusses the most relevant biomolecules that can be successfully purified by them. We describe success stories for viruses, nucleic acids and proteins and compare them to conventional purification methods. Furthermore, the advantages of monolithic columns over particle-based resins, as well as the limitations of monoliths are discussed. With a compilation of commercially available monolithic columns, this review aims at serving as a ‘yellow pages’ for bioprocess engineers who face the challenge of purifying a certain biomolecule using monoliths.

  18. Silicon photomultiplier readout of a monolithic 270×5×5 cm3 plastic scintillator bar for time of flight applications

    Science.gov (United States)

    Reinhardt, Tobias P.; Gohl, Stefan; Reinicke, Stefan; Bemmerer, Daniel; Cowan, Thomas E.; Heidel, Klaus; Röder, Marko; Stach, Daniel; Wagner, Andreas; Weinberger, David; Zuber, Kai

    2016-04-01

    The detection of 200-1000 MeV neutrons requires large amounts, ~ 100 cm, of detector material because of the long nuclear interaction length of these particles. In the example of the NeuLAND neutron time-of-flight detector at FAIR, this is accomplished by using 3000 monolithic scintillator bars of 270 × 5 × 5cm3 size made of a fast plastic. Each bar is read out on the two long ends, and the needed time resolution of σt ELBE superconducting electron linac. The ELBE data were matched by a simple Monte Carlo simulation, and they were found to obey an inverse-square-root scaling law. In the electron beam tests, a time resolution of σt = 136 ps was reached with a pure SiPM readout, well within the design parameters for NeuLAND.

  19. Droplets Fusion in a Microchannel on a Piezoelectric Substrate

    Directory of Open Access Journals (Sweden)

    Fu Xiang-ting

    2013-07-01

    Full Text Available Fusion droplets is a key operation in a microfluidic device for microfluidic analysis. A new fusion method for droplets was presented. An interditigal transducer and a reflector were fabricated on 1280-yx LiNbO3 piezoelectric substrate using microelectric technology. A poly-dimethyl silicone micro-channel was made by soft lithography technology and mounted on the piezoelectric substrate. Droplets in the microchannel were actuated by surface acoustic wave and fussed each other. Coloured dye solution droplets were used to fusion experiments. Results show that the two droplets in the microchannel can be fused by help of surface acoustic wave, and size of droplets, distance of droplets and RF signal power can affect successful fusion of the droplets. The fusion method is valuable for microlfuidic biological and chemical analysis in a microfluidic device.

  20. A CMOS-compatible large-scale monolithic integration of heterogeneous multi-sensors on flexible silicon for IoT applications

    KAUST Repository

    Nassar, Joanna M.

    2017-02-07

    We report CMOS technology enabled fabrication and system level integration of flexible bulk silicon (100) based multi-sensors platform which can simultaneously sense pressure, temperature, strain and humidity under various physical deformations. We also show an advanced wearable version for body vital monitoring which can enable advanced healthcare for IoT applications.

  1. Microchannel plate streak camera

    Science.gov (United States)

    Wang, Ching L.

    1989-01-01

    An improved streak camera in which a microchannel plate electron multiplier is used in place of or in combination with the photocathode used in prior streak cameras. The improved streak camera is far more sensitive to photons (UV to gamma-rays) than the conventional x-ray streak camera which uses a photocathode. The improved streak camera offers gamma-ray detection with high temporal resolution. It also offers low-energy x-ray detection without attenuation inside the cathode. Using the microchannel plate in the improved camera has resulted in a time resolution of about 150 ps, and has provided a sensitivity sufficient for 1000 KeV x-rays.

  2. Compact microchannel system

    Science.gov (United States)

    Griffiths, Stewart

    2003-09-30

    The present invention provides compact geometries for the layout of microchannel columns through the use of turns and straight channel segments. These compact geometries permit the use of long separation or reaction columns on a small microchannel substrate or, equivalently, permit columns of a fixed length to occupy a smaller substrate area. The new geometries are based in part on mathematical analyses that provide the minimum turn radius for which column performance in not degraded. In particular, we find that straight channel segments of sufficient length reduce the required minimum turn radius, enabling compact channel layout when turns and straight segments are combined. The compact geometries are obtained by using turns and straight segments in overlapped or nested arrangements to form pleated or coiled columns.

  3. Continuous acoustic separation in a thermoplastic microchannel

    Science.gov (United States)

    Mueller, A.; Lever, A.; Nguyen, T. V.; Comolli, J.; Fiering, J.

    2013-12-01

    Acoustic manipulation of particles and cells has been widely used for trapping and separation in microfluidic devices. Previously, the resonant components of these devices have been fabricated from silicon, glass, metals, or other materials having high acoustic impedance. Here, we present experimental results showing continuous acoustic focusing and separation of blood cells in a microchannel fabricated entirely from polystyrene. The efficiency and flow rates approach those reported in silicon and glass systems. We find that the optimum operating frequencies differ from those predicted by conventional approximations which have been developed for more rigid materials. Additionally, we introduce a method for fabrication of the devices, using an adaptation of thermofusion bonding that preserves critical channel dimensions. To control channel cross section during bonding, we introduced a collapsible fiberboard material in the bonding press. This structure provided a self-limiting force and mitigated deformation of the polystyrene. Together, these advances may enable new applications for acoustic focusing and separation in medical devices.

  4. Fractal multifiber microchannel plates

    Science.gov (United States)

    Cook, Lee M.; Feller, W. B.; Kenter, Almus T.; Chappell, Jon H.

    1992-01-01

    The construction and performance of microchannel plates (MCPs) made using fractal tiling mehtods are reviewed. MCPs with 40 mm active areas having near-perfect channel ordering were produced. These plates demonstrated electrical performance characteristics equivalent to conventionally constructed MCPs. These apparently are the first MCPs which have a sufficiently high degree of order to permit single channel addressability. Potential applications for these devices and the prospects for further development are discussed.

  5. Microscope-assisted UV-initiated preparation of well-defined porous polymer monolithic plugs in glass microchips for peptide preconcentration.

    Science.gov (United States)

    Dziomba, Szymon; Araya-Farias, Monica; Taverna, Myriam; Guerrouache, Mohamed; Carbonnier, Benjamin; Tran, N Thuy

    2017-03-01

    Herein, highly defined monolithic beds were prepared in glass microchips by photopolymerization of ethylene glycol methacrylate phosphate (EGMP), acrylamide, and N,N'-methylenebisacrylamide (BAA) using an epifluorescence microscope as UV-irradiation source. Such a fast and easy method allowed precise control of (i) the edge shape, (ii) the location along the microchannel, and (iii) the length of the monolithic plugs within glass microchips. The addition of hydroquinone, a polymerization inhibitor, to the prepolymerization mixture was beneficial for achieving local and robust incorporation of monoliths with sharp edges within microchannels. The monolith length was easily tuned from 160 to 400 μm through simple change in the magnification of the objective and was found to be repeatable (relative standard deviation microscope-UV-synthesis of monolithic plugs with sharp edges.

  6. Micro-channel plate detector

    Science.gov (United States)

    Elam, Jeffrey W.; Lee, Seon W.; Wang, Hsien -Hau; Pellin, Michael J.; Byrum, Karen; Frisch, Henry J.

    2015-09-22

    A method and system for providing a micro-channel plate detector. An anodized aluminum oxide membrane is provided and includes a plurality of nanopores which have an Al coating and a thin layer of an emissive oxide material responsive to incident radiation, thereby providing a plurality of radiation sensitive channels for the micro-channel plate detector.

  7. Theoretical Aspects of Microchannel Acoustofluidics

    DEFF Research Database (Denmark)

    Muller, Peter Barkholt; Bruus, Henrik

    2014-01-01

    We study the effects of the temperature dependence of viscosity and density on the acoustic radiation force and the boundary-driven acoustic streaming in microchannel acoustofluidics. The acoustic streaming slip velocity for the bulk flow is calculated numerically taking these thermoviscous effects......) is analyzed for microchannel acoustophoresis....

  8. Hybrid and monolithic integration of planar lightwave circuits (PLCs)

    Science.gov (United States)

    Chen, Ray T.

    2008-02-01

    In this paper, we review the status of monolithic and hybrid integration of planar lightwave circuits (PLCs). Building blocks needed for system integration based on polymeric materials, III-V semiconductor materials, LiNbO 3 and SOI on Silicon are summarized with pros and cons. Due to the maturity of silicon CMOS technology, silicon becomes the platform of choice for optical application specific integrated circuits (OASICs). However, the indirect bandgap of silicon makes the formation of electrically pumped silicon laser a remote plausibility which requires hybrid integration of laser sources made out of III-V compound semicouductor.

  9. Fluorinated silica microchannel surfaces

    Science.gov (United States)

    Kirby, Brian J.; Shepodd, Timothy Jon

    2005-03-15

    A method for surface modification of microchannels and capillaries. The method produces a chemically inert surface having a lowered surface free energy and improved frictional properties by attaching a fluorinated alkane group to the surface. The coating is produced by hydrolysis of a silane agent that is functionalized with either alkoxy or chloro ligands and an uncharged C.sub.3 -C.sub.10 fluorinated alkane chain. It has been found that the extent of surface coverage can be controlled by controlling the contact time from a minimum of about 2 minutes to a maximum of 120 minutes for complete surface coverage.

  10. Silicon Carbide Corrugated Mirrors for Space Telescopes Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Trex Enterprises Corporation (Trex) proposes technology development to manufacture monolithic, lightweight silicon carbide corrugated mirrors (SCCM) suitable for...

  11. Multiple-Dynode-Layer Microchannel Plate

    Science.gov (United States)

    Woodgate, Bruce E.

    1990-01-01

    Improved microchannel-plate electron image amplifier made of stack of discrete microchannel-plate layers. New plates easier to manufacture because no need to etch long, narrow holes, to draw and bundle thin glass tubes, or to shear plates to give microchannels curvatures necessary for reduction of undesired emission of ions. Discrete dynode layers stacked with slight offset from layer to layer to form microchannel plate with curved channels. Provides for relatively fast recharging of microchannel dynodes, with consequent enhancement of performance.

  12. Deposition of a-C:H films on inner surface of high-aspect-ratio microchannel

    Science.gov (United States)

    Hirata, Yuki; Choi, Junho

    2016-08-01

    Hydrogenated amorphous carbon (a-C:H) films were prepared on inner surface of 100-μm-width microchannel by using a bipolar-type plasma based ion implantation and deposition. The microchannel was fabricated using a silicon plate, and two kinds of microchannels were prepared, namely, with a bottom layer (open at one end) and without a bottom layer (open at both ends). The distribution of thickness and hardness of films was evaluated by SEM and nanoindentation measurements, respectively, and the microstructures of films were evaluated by Raman spectroscopy. Furthermore, the behavior of ions and radicals was analyzed simultaneously by combining the calculation methods of Particle-In-Cell/Monte Carlo Collision and Direct Simulation Monte Carlo to investigate the coating mechanism for the microchannel. It was found that the film thickness decreased as the depth of the coating position increased in the microchannels where it is open at one end. The uniformity of the film thickness improved by increasing the negative pulse voltage because ions can arrive at the deeper part of the microchannel. In addition, the hardness increased as the depth of the coating position increased. This is because the radicals do not arrive at the deeper part of the microchannel, and the incident proportion of ions relative to that of radicals increases, resulting in a high hardness due to the amorphization of the film. The opening area of the microchannel where the aspect ratio is very small, radicals dominate the incident flux, whereas ions prevail over radicals above an aspect ratio of about 7.5. On the other hand, in the microchannels that are open at both ends, there were great improvements in uniformity of the film thickness, hardness, and the film structure. The a-C:H films were successfully deposited on the entire inner surface of a microchannel with an aspect ratio of 20.

  13. Rapid and simple preparation of thiol-ene emulsion-templated monoliths and their application as enzymatic microreactors

    DEFF Research Database (Denmark)

    Lafleur, Josiane P; Senkbeil, Silja; Novotny, Jakub;

    2015-01-01

    electron microscopy showed that the methanol-based emulsion templating process resulted in a network of highly interconnected and regular thiol-ene beads anchored solidly inside thiol-ene microchannels. Surface area measurements indicate that the monoliths are macroporous, with no or little micro...

  14. Separation process using microchannel technology

    Science.gov (United States)

    Tonkovich, Anna Lee; Perry, Steven T.; Arora, Ravi; Qiu, Dongming; Lamont, Michael Jay; Burwell, Deanna; Dritz, Terence Andrew; McDaniel, Jeffrey S.; Rogers, Jr.; William A.; Silva, Laura J.; Weidert, Daniel J.; Simmons, Wayne W.; Chadwell, G. Bradley

    2009-03-24

    The disclosed invention relates to a process and apparatus for separating a first fluid from a fluid mixture comprising the first fluid. The process comprises: (A) flowing the fluid mixture into a microchannel separator in contact with a sorption medium, the fluid mixture being maintained in the microchannel separator until at least part of the first fluid is sorbed by the sorption medium, removing non-sorbed parts of the fluid mixture from the microchannel separator; and (B) desorbing first fluid from the sorption medium and removing desorbed first fluid from the microchannel separator. The process and apparatus are suitable for separating nitrogen or methane from a fluid mixture comprising nitrogen and methane. The process and apparatus may be used for rejecting nitrogen in the upgrading of sub-quality methane.

  15. Preparation of gradient polyacrylate brushes in microchannels.

    Science.gov (United States)

    Lee, Seongyeol; Youm, Sang Gil; Song, Yeari; Yi, Whikum; Sohn, Daewon

    2012-05-01

    Gradient poly(2-hydroxyethyl methacrylate) brushes were synthesized by surface-initiated atom transfer radical polymerization (ATRP) confined within a microfluidic system on a silicon wafer. For ATRP, surface initiator, 11-((2-bromo, 2-methyl) propionyloxy) undecyltrichlorosilane (BUC), was synthesized, and allowed to self-assemble in a monolayer on the Si wafer, as analyzed by XPS to confirm the presence of an ester group of BUC. A solution containing 2-hydroxyethylmethacrylate, Cu catalyst, and bipyridin was allowed to flow in a microchannel and polymerize, resulting in the brushes with a gradient of thickness on the Si wafer. Using ellipsometry and ATR-IR, we verified the gradients of well established brushes on the Si wafer. AFM and contact angle data showed that wettability of the brushes did not exhibit a linear relationship with hydrophilicity.

  16. Affinity Monolith-Integrated Microchips for Protein Purification and Concentration.

    Science.gov (United States)

    Gao, Changlu; Sun, Xiuhua; Wang, Huaixin; Qiao, Wei; Hu, Bo

    2016-01-01

    Affinity chromatography is a valuable method to purify and concentrate minute amount of proteins. Monoliths with epoxy groups for affinity immobilization were prepared by direct in-situ photopolymerization of glycidyl methacrylate and ethylene glycol dimethacrylate in porogenic solvents consisting of 1-dodecanol and cyclohexanol. By integrating affinity monoliths onto a microfluidic system, targeted biomolecules can be captured and retained on affinity column, while other biomolecules having no specific interactions toward the immobilized ligands flow through the microchannel. Therefore, proteins which remain on the affinity column are purified and concentrated, and then eluted by appropriate solutions and finally, separated by microchip capillary electrophoresis. This integrated microfluidic device has been applied to the purification and separation of specific proteins (FITC-labeled human serum albumin and IgG) in a mixture.

  17. Capillary driven flow of polydimethylsiloxane in open rectangular microchannels.

    Science.gov (United States)

    Sowers, Timothy W; Sarkar, Rohit; Eswarappa Prameela, Suhas; Izadi, Ehsan; Rajagopalan, Jagannathan

    2016-06-29

    The flow of liquid polydimethylsiloxane (PDMS, Dow Corning Sylgard 184, 10 : 1 base to cross-linker ratio) in open, rectangular silicon microchannels, with and without a coating (100 nm) of poly-tetra-fluoro-ethylene (PTFE), was studied. Photolithographic patterning and etching of silicon wafers was used to create microchannels with a range of widths (∼5-50 μm) and depths (5-20 μm). Experimental PDMS flow rates in both PTFE-coated and uncoated channels were compared to an analytical model based on the work of Lucas and Washburn. The experimental flow rates matched the predicted flow rates reasonably well when the channel aspect ratio (width to depth), p, was less than 2. For channels with p > 2, the observed flow rates progressively lagged model predictions with increasing p. The experimental data, including zero flow rates in certain high aspect ratio PTFE-coated channels, can largely be explained by changes in the front and upper meniscus morphology of the flow as the channel aspect ratio is varied. The results strongly suggest that meniscus morphology needs to be taken into account to accurately model capillary flow in microchannels, especially those with large aspect ratios.

  18. Monolithic pixel detectors for high energy physics

    CERN Document Server

    Snoeys, W

    2013-01-01

    Monolithic pixel detectors integrating sensor matrix and readout in one piece of silicon have revolutionized imaging for consumer applications, but despite years of research they have not yet been widely adopted for high energy physics. Two major requirements for this application, radiation tolerance and low power consumption, require charge collection by drift for the most extreme radiation levels and an optimization of the collected signal charge over input capacitance ratio ( Q / C ). It is shown that monolithic detectors can achieve Q / C for low analog power consumption and even carryout the promise to practically eliminate analog power consumption, but combining suf fi cient Q / C , collection by drift, and integration of readout circuitry within the pixel remains a challenge. An overview is given of different approaches to address this challenge, with possible advantages and disadvantages.

  19. A Monolithically Integrated Silicon Modulator with a 10Gb/s 5Vpp or 5.6Vpp Driver in 0.25µm SiGe:C BiCMOS

    Directory of Open Access Journals (Sweden)

    Bernhard eGoll

    2014-11-01

    Full Text Available This paper presents as a novelty a fully monolithically integrated 10Gb/s silicon modulator consisting of an electrical driver plus optical phase modulator in 0.25µm SiGe:C BiCMOS technology on one chip, where instead of a SOI CMOS process (only MOS transistors a SiGe BiCMOS process (MOS transistors and fast SiGe bipolar transistors is implemented. The fastest bipolar transistors in the BiCMOS product line used have a transit frequency of 120GHz and a collector-emitter breakdown voltage of 2.2V (IHP SG25H3. The main focus of this paper will be given to the electronic drivers, where two driver variants are implemented in the test chips. Circuit descriptions and simulations, which treat the influences of noise and bond wires, are presented. Measurements at separate test chips for the drivers show that the integrated driver variant one has a low power consumption in the range of 0.66W to 0.68W but a high gain of S21=37dB. From the large signal point of view this driver delivers an inverted as well as a non-inverted output data signal between 0V and 2.5V (5Vpp differential. Driver variant one is supplied with 2.5V and with 3.5V. Bit-error-ratio (BER measurements resulted in a BER better than 10E-12 for voltage differences of the input data stream down to 50mVpp. Driver variant two, which is an adapted version of driver variant one, is supplied with 2.5V and 4.2V, consumes 0.83W to 0.87W, delivers a differential data signal with 5.6Vpp at the output and has a gain of S21=40dB. The chip of the fully integrated modulator occupies an area of 12.3mm^2 due to the photonic components. Measurements with a 240mVpp electrical input data stream and for an optical input wavelength of 1540nm resulted in an extinction ratio of 3.3dB for 1mm long RF phase shifters in each modulator arm driven by driver variant one and a DC tuning voltage of 1.2V. The extinction ratio was 8.4dB at a DC tuning voltage of 7V for a device with 2mm long RF phase shifters and driver

  20. Fanno Flow in Microchannels

    Directory of Open Access Journals (Sweden)

    M.A. Al-Nimr

    2012-12-01

    Full Text Available In this study, the Fanno flow problem has been theoretically investigated using both, first order and second order velocity-slip boundary conditions models and then compared to the no-slip boundary conditions solution. The objective is to study the behavior of the flow predicted by the two slip models. Then, an attempt will be made to establish criteria for using the no-slip and the two velocity-slip models. The Fanno flow is an ideal gas adiabatic flow in constant area duct with friction. It is found that the velocity profile for the two velocity-slip models has the same shape as the no-slip model velocity profile but with an amount of slip at the wall which increases as the Knudsen number, Kn, increases. Also the effect of the slip has on the compressible flow characteristics have been examined. It shows that as the Kn increases, the skin friction coefficient Cf and the Darcy friction coefficient f decrease. Overall, it is concluded that for an adiabatic compressible flow in circular microchannel, for Kn≤0.01 there is no need to apply any velocity-slip model as the no-slip model gives sufficiently accurate predictions. As for the range 0.01≤Kn≤0.1, the first order velocity slip model should be applied and so for this range, there is no necessity to use the second order velocity-slip model.

  1. Highly curved microchannel plates

    Science.gov (United States)

    Siegmund, O. H. W.; Cully, S.; Warren, J.; Gaines, G. A.; Priedhorsky, W.; Bloch, J.

    1990-01-01

    Several spherically curved microchannel plate (MCP) stack configurations were studied as part of an ongoing astrophysical detector development program, and as part of the development of the ALEXIS satellite payload. MCP pairs with surface radii of curvature as small as 7 cm, and diameters up to 46 mm have been evaluated. The experiments show that the gain (greater than 1.5 x 10 exp 7) and background characteristics (about 0.5 events/sq cm per sec) of highly curved MCP stacks are in general equivalent to the performance achieved with flat MCP stacks of similar configuration. However, gain variations across the curved MCP's due to variations in the channel length to diameter ratio are observed. The overall pulse height distribution of a highly curved surface MCP stack (greater than 50 percent FWHM) is thus broader than its flat counterpart (less than 30 percent). Preconditioning of curved MCP stacks gives comparable results to flat MCP stacks, but it also decreases the overall gain variations. Flat fields of curved MCP stacks have the same general characteristics as flat MCP stacks.

  2. Evaporation from open microchannel grooves.

    Science.gov (United States)

    Kachel, Sibylle; Zhou, Ying; Scharfer, Philip; Vrančić, Christian; Petrich, Wolfgang; Schabel, Wilhelm

    2014-02-21

    The evaporation of water from open u-shaped microchannel grooves was investigated with particular emphasis on the roles of channel width and air flow conditions. Given the small dimensions of the microchannels, all measurements were conducted in a range where convection and diffusion are of equal importance and known correlations for the calculation of mass transfer coefficients cannot be applied. The evaporation rates were measured using a new optical method and a gravimetric method. Both measurement methods yielded mass transfer coefficients that are in agreement with each other. The observed relation between mass transfer coefficient, air velocity and channel width vastly differs from the predictions obtained from macroscopic structures. With respect to diagnostic devices we conclude that analyte concentration in an open microchannel groove strongly increases even within short times due to the evaporation process and we show that wider channels are more favourable in terms of minimizing the relative evaporation rate.

  3. Monolithic cells for solar fuels.

    Science.gov (United States)

    Rongé, Jan; Bosserez, Tom; Martel, David; Nervi, Carlo; Boarino, Luca; Taulelle, Francis; Decher, Gero; Bordiga, Silvia; Martens, Johan A

    2014-12-07

    Hybrid energy generation models based on a variety of alternative energy supply technologies are considered the best way to cope with the depletion of fossil energy resources and to limit global warming. One of the currently missing technologies is the mimic of natural photosynthesis to convert carbon dioxide and water into chemical fuel using sunlight. This idea has been around for decades, but artificial photosynthesis of organic molecules is still far away from providing real-world solutions. The scientific challenge is to perform in an efficient way the multi-electron transfer reactions of water oxidation and carbon dioxide reduction using holes and single electrons generated in an illuminated semiconductor. In this tutorial review the design of photoelectrochemical (PEC) cells that combine solar water oxidation and CO2 reduction is discussed. In such PEC cells simultaneous transport and efficient use of light, electrons, protons and molecules has to be managed. It is explained how efficiency can be gained by compartmentalisation of the water oxidation and CO2 reduction processes by proton exchange membranes, and monolithic concepts of artificial leaves and solar membranes are presented. Besides transferring protons from the anode to the cathode compartment the membrane serves as a molecular barrier material to prevent cross-over of oxygen and fuel molecules. Innovative nano-organized multimaterials will be needed to realise practical artificial photosynthesis devices. This review provides an overview of synthesis techniques which could be used to realise monolithic multifunctional membrane-electrode assemblies, such as Layer-by-Layer (LbL) deposition, Atomic Layer Deposition (ALD), and porous silicon (porSi) engineering. Advances in modelling approaches, electrochemical techniques and in situ spectroscopies to characterise overall PEC cell performance are discussed.

  4. Monolithic microwave integrated circuits

    Science.gov (United States)

    Pucel, R. A.

    Monolithic microwave integrated circuits (MMICs), a new microwave technology which is expected to exert a profound influence on microwave circuit designs for future military systems as well as for the commercial and consumer markets, is discussed. The book contains an historical discussion followed by a comprehensive review presenting the current status in the field. The general topics of the volume are: design considerations, materials and processing considerations, monolithic circuit applications, and CAD, measurement, and packaging techniques. All phases of MMIC technology are covered, from design to testing.

  5. Silicon buried channels for pixel detector cooling

    Energy Technology Data Exchange (ETDEWEB)

    Boscardin, M., E-mail: boscardi@fbk.eu [Fondazione Bruno Kessler Trento, Via Sommarive 18, I-38123 Trento (Italy); Conci, P.; Crivellari, M.; Ronchin, S. [Fondazione Bruno Kessler Trento, Via Sommarive 18, I-38123 Trento (Italy); Bettarini, S. [Universitá di Pisa, L.go B. Pontecorvo 3, I-56127 Pisa (Italy); Istituto Nazionale di Fisica Nucleare, Sez. di Pisa, L.go B. Pontecorvo 3, I-56127 Pisa (Italy); Bosi, F. [Istituto Nazionale di Fisica Nucleare, Sez. di Pisa, L.go B. Pontecorvo 3, I-56127 Pisa (Italy)

    2013-08-01

    The support and cooling structures add important contributions to the thickness, in radiation length, of vertex detectors. In order to minimize the material budget of pixel sensors, we developed a new approach to integrate the cooling into the silicon devices. The microchannels are formed in silicon using isotropic SF{sub 6} plasma etching in a DRIE (deep reactive ion etcher) equipment. Due to their peculiar profiles, the channels can be sealed by a layer of a PECVD silicon oxide. We have realized on a silicon wafer microchannels with different geometries and hydraulic diameters. We describe the main fabrication steps of microchannels with focus on the channel definition. The experimental results are reported on the thermal characterization of several prototypes, using a mixture of glycol and water as a liquid coolant. The prototypes have shown high cooling efficiency and high-pressure breaking strength.

  6. Electroosmotic shear flow in microchannels

    NARCIS (Netherlands)

    Mampallil, Dileep; Ende, van den Dirk

    2013-01-01

    We generate and study electroosmotic shear flow in microchannels. By chemically or electrically modifying the surface potential of the channel walls a shear flow component with controllable velocity gradient can be added to the electroosmotic flow caused by double layer effects at the channel walls.

  7. Fully integrated monolithic opoelectronic transducer for real.time protein and DNA detection

    DEFF Research Database (Denmark)

    Misiakos, Konstatinos; S. Petrou, Panagiota; E. Kakabakos, Sotirios

    2010-01-01

    The development and testing of a portable bioanalytical device which was capable for real-time monitoring of binding assays was demonstrated. The device was based on arrays of nine optoelectronic transducers monolithically integrated on silicon chips. The optocouplers consisted of nine silicon av...

  8. Embedded-monolith armor

    Science.gov (United States)

    McElfresh, Michael W.; Groves, Scott E; Moffet, Mitchell L.; Martin, Louis P.

    2016-07-19

    A lightweight armor system utilizing a face section having a multiplicity of monoliths embedded in a matrix supported on low density foam. The face section is supported with a strong stiff backing plate. The backing plate is mounted on a spall plate.

  9. Microchannel apparatus comprising plural microchannels and methods of conducting unit operations

    Science.gov (United States)

    Wegeng, Robert S [Richland, WA; TeGrotenhuis, Ward E [Kennewick, WA; Whyatt, Greg A [West Richland, WA

    2009-03-10

    Microchannel apparatus comprising a header and plural flow microchannels is described in which orifices connect the header and the flow microchannels. The orifices constrict flow. The ratio of the cross-sectional area of each of the orifices to the cross-sectional area of the flow microchannels connected to the orifices is between 0.0005 and 0.1. Also described is microchannel apparatus for conducting unit operations in which a device comprises two arrays of microchannels, and a unit operation is conducted on a fluid as it passes through the first set of microchannels and into a header where a second unit operation is performed, and then the fluid stream passes into the second array of microchannels where the first unit operation is again performed. Methods of conducting unit operations in the apparatuses are also described.

  10. CFD Analysis for Optimum Thermal Design of Carbon Nanotube Based Micro-Channel Heatsink

    Directory of Open Access Journals (Sweden)

    M. Mahbub

    2011-10-01

    Full Text Available Carbon nanotube (CNT is considered as an ideal material for thermal management in electronic packaging because of its extraordinary high thermal conductivity. Fabricated onto a silicon substrate to form micro-channels, the CNT based cooling fins show high heat dissipation efficiency. A series of 2D and 3D CFD simulations have been carried out for CNT based micro-channel cooling architectures based on one and two dimensional fin array in this paper using COMSOL 4.0a software. Micro-channels are generally regarded as an effective method for the heat transfer in electronic products. The influence of various fluids, micro-fin structures, fluid velocity and heating powers on cooling effects have been simulated and compared in this study. Steady-state thermal stress analyses for the forced convection heat transfer are also performed to determine maximum allowable stress and deflections for the different types of cooling assembly.

  11. Surface Smoothing of Blasted Glass Micro-Channels Using Abrasive Waterjet

    Energy Technology Data Exchange (ETDEWEB)

    Son, Sunggyun; Han, Solyi; Kim, Wookbae [Korea Polytechnic Univ., Siheung (Korea, Republic of); Sung, Inha [Hannam Univ., Daejeon (Korea, Republic of)

    2013-12-15

    Powder blasting, which is an efficient micromachining method for glass, silicon, and ceramics, has a critical disadvantage in that the surface finish is poor owing to the brittle fracture of materials. Low-pressure waterjet machining can be applied to smoothen the rough surface inside the blasted structure. In this study, the surface roughness and sectional dimension of micro-channels are observed during the repetitive application of a waterjet to blasted micro-channels. The asperities and subsurface cracks created by blasting are removed by waterjet machining. Along with the surface roughness, it is found that the sectional dimension increases and the edges of the finished micro-channel become slightly round. Finally, a microfluidic chip is machined by the blasting-waterjet process and a transparent microfluidic channel is obtained efficiently.

  12. Monolithic MACS micro resonators

    Science.gov (United States)

    Lehmann-Horn, J. A.; Jacquinot, J.-F.; Ginefri, J. C.; Bonhomme, C.; Sakellariou, D.

    2016-10-01

    Magic Angle Coil Spinning (MACS) aids improving the intrinsically low NMR sensitivity of heterogeneous microscopic samples. We report on the design and testing of a new type of monolithic 2D MACS resonators to overcome known limitations of conventional micro coils. The resonators' conductors were printed on dielectric substrate and tuned without utilizing lumped element capacitors. Self-resonance conditions have been computed by a hybrid FEM-MoM technique. Preliminary results reported here indicate robust mechanical stability, reduced eddy currents heating and negligible susceptibility effects. The gain in B1 /√{ P } is in agreement with the NMR sensitivity enhancement according to the principle of reciprocity. A sensitivity enhancement larger than 3 has been achieved in a monolithic micro resonator inside a standard 4 mm rotor at 500 MHz. These 2D resonators could offer higher performance micro-detection and ease of use of heterogeneous microscopic substances such as biomedical samples, microscopic specimens and thin film materials.

  13. The MONOLITH prototype

    CERN Document Server

    Ambrosio, M; Bencivenni, G; Candela, A M; Chiarini, A; Chignoli, F; De Deo, M; D'Incecco, M; Gerli, S; Giusti, P; Gómez, F; Gustavino, C; Lindozzi, M; Mannocchi, G; Menghetti, H; Morello, C; Murtas, F; Paoluzzi, G; Pilastrini, R; Redaelli, N G; Santoni, M; Sartorelli, G; Terranova, F; Trinchero, G C

    2000-01-01

    MONOLITH (Massive Observatory for Neutrino Oscillation or LImits on THeir existence) is the project of an experiment to study atmospheric neutrino oscillations with a massive magnetized iron detector. The baseline option is a 34 kt iron detector based on the use of about 50000 m/sup 2/ of the glass Resistive Plate Chambers (glass RPCs) developed at the Laboratori Nazionali del Gran Sasso (LNGS). An 8 ton prototype equipped with 23 m/sup 2/ of glass RPC has been realized and tested at the T7-PS beam at CERN. The energy resolution for pions follows a 68%/ square root (E(GeV))+2% law for orthogonally incident particles, in the energy range between 2 and 10 GeV. The time resolution and the tracking capability of the glass RPC are suitable for the MONOLITH experiment. (7 refs).

  14. Cooling Augmentation with Microchanneled Structures

    Institute of Scientific and Technical Information of China (English)

    X.F.Peng; B.X.Wang

    1993-01-01

    Experiments were conducted to investigate the heat transfer characteristics and cooling performance of subcooled liquid,water,flowing through rectangular cross-section microchanneled structures machined on a stainless steel plate.Heat transfer or flow mode stransition was observed when the heating rate or wall temperature was increased.This transition was found to be suggestively induced by the variation in liquid thermophysical properties due to the significant rise of liquid temperature in the microstructures.The influence of such parameters as liquid velocity,subcooling,property variation,and microchannel geometric configuration on the heat transfer behavior,cooling performance and the heat transfer and liquid flow mode transition were also investigated.The experiments indicated that both single-phase forced convection and flow boiling characteristics were quite different from those in normal-sized tubes and the heat transfer was obviously intensified.

  15. Microchannel systems for fine organic synthesis

    Science.gov (United States)

    Makarshin, L. L.; Pai, Z. P.; Parmon, V. N.

    2016-02-01

    Characteristic features of application of microchannel systems in organic synthesis are analyzed. The advantages of such systems over conventional chemical engineering equipment, especially for small-scale processes that require fast implementation in industry to obtain small quantities of the product, are shown. Particular examples of successful use of microchannel reactors for various types of organic synthesis are given, primary attention being devoted to the design features of microchannel reactors. The bibliography includes 118 references.

  16. Instability in flow boiling in microchannels

    CERN Document Server

    Saha, Sujoy Kumar

    2016-01-01

    This Brief addresses the phenomena of instability in flow boiling in microchannels occurring in high heat flux electronic cooling. A companion edition in the SpringerBrief Subseries on Thermal Engineering and Applied Science to “Critical Heat Flux in Flow Boiling in Microchannels,” and "Heat Transfer and Pressure Drop in Flow Boiling in Microchannels,"by the same author team, this volume is idea for professionals, researchers, and graduate students concerned with electronic cooling.

  17. Distillation process using microchannel technology

    Science.gov (United States)

    Tonkovich, Anna Lee; Simmons, Wayne W.; Silva, Laura J.; Qiu, Dongming; Perry, Steven T.; Yuschak, Thomas; Hickey, Thomas P.; Arora, Ravi; Smith, Amanda; Litt, Robert Dwayne; Neagle, Paul

    2009-11-03

    The disclosed invention relates to a distillation process for separating two or more components having different volatilities from a liquid mixture containing the components. The process employs microchannel technology for effecting the distillation and is particularly suitable for conducting difficult separations, such as the separation of ethane from ethylene, wherein the individual components are characterized by having volatilities that are very close to one another.

  18. Gas-Liquid Slug Flow in Microchannels

    Science.gov (United States)

    Guenther, Axel; de Mas, Nuria; Jhunjhunwala, Manish; Schmidt, Martin A.; Jensen, Klavs F.

    2003-11-01

    Slug flow is not only an attractive regime for conducting gas-liquid reactions in microchemical systems. It also provides a normal velocity that enhances liquid mixing for high Peclet number flows, e.g. for particle synthesis. We previously extended the flow regime diagrams initially obtained for micro heat-exchangers to the liquid deficient conditions relevant to microreactors. We use silicon-based single microchannels with rectangular and triangular cross-section and hydraulic diameters of 40-400 microns that are capped with Pyrex to provide for optical access. Ethanol, water, toluene, and nitrogen are the working fluids. Superficial velocities are varied between 0.01 and 10 m/s for the gas and 0.001 and 1 m/s for the liquid with corresponding Capillary and Bond numbers between 0.001 and 0.01. We complement pulsed-laser fluorescence microscopy and confocal scanning microscopy with a non-intrusive optical sensor to monitor the transient flow at sampling rates of 10 kHz. Interfacial area, void fraction, slug velocity U_s, and the transversal velocity component introduced by internal circulation in the liquid are determined. For comparable Peclet numbers, the transverse velocity between channel wall and center is lO0.1 U_s and allows for shorter mixing lengths than reported for micromixers with patterned walls. Gas and liquid are completely separated on-chip subsequent to the mixing step.

  19. Boiling flow through diverging microchannel

    Indian Academy of Sciences (India)

    V S Duryodhan; S G Singh; Amit Agrawal

    2013-12-01

    An experimental study of flow boiling through diverging microchannel has been carried out in this work, with the aim of understanding boiling in nonuniform cross-section microchannel. Diverging microchannel of 4° of divergence angle and 146 m hydraulic diameter (calculated at mid-length) has been employed for the present study with deionised water as working fluid. Effect of mass flux (118–1182 kg/m2-s) and heat flux (1.6–19.2 W/cm2) on single and two-phase pressure drop and average heat transfer coefficient has been studied. Concurrently, flow visualization is carried out to document the various flow regimes and to correlate the pressure drop and average heat transfer coefficient to the underlying flow regime. Four flow regimes have been identified from the measurements: bubbly, slug, slug–annular and periodic dry-out/rewetting. Variation of pressure drop with heat flux shows one maxima which corresponds to transition from bubbly to slug flow. It is shown that significantly large heat transfer coefficient (up to 107 kW/m2-K) can be attained for such systems, for small pressure drop penalty and with good flow stability.

  20. Hybrid slab-microchannel gel electrophoresis system

    Science.gov (United States)

    Balch, Joseph W.; Carrano, Anthony V.; Davidson, James C.; Koo, Jackson C.

    1998-01-01

    A hybrid slab-microchannel gel electrophoresis system. The hybrid system permits the fabrication of isolated microchannels for biomolecule separations without imposing the constraint of a totally sealed system. The hybrid system is reusable and ultimately much simpler and less costly to manufacture than a closed channel plate system. The hybrid system incorporates a microslab portion of the separation medium above the microchannels, thus at least substantially reducing the possibility of non-uniform field distribution and breakdown due to uncontrollable leakage. A microslab of the sieving matrix is built into the system by using plastic spacer materials and is used to uniformly couple the top plate with the bottom microchannel plate.

  1. Enhanced dibenzothiophene biodesulfurization in a microchannel reactor.

    Science.gov (United States)

    Noda, Ken-Ichi; Kogure, Tomonari; Irisa, Shiro; Murakami, Yuji; Sakata, Minoru; Kuroda, Akio

    2008-03-01

    A microchannel reactor system was used in a biodesulfurization process in which the rate of biodesulfurization in the oil/water phase of the microchannel reaction was more than nine-fold that in a batch (control) reaction. In addition, the microchannel reaction system using a bacterial cell suspension degraded alkylated dibenzothiophene that was not degraded by the batch reaction system. This work provides a foundation for the application of a microchannel reactor system consisting of biological catalysts using an oil/water phase reaction.

  2. Microchannel Methanation Reactors Using Nanofabricated Catalysts Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Makel Engineering, Inc. (MEI) and the Pennsylvania State University (Penn State) propose to develop and demonstrate a microchannel methanation reactor based on...

  3. Scaleable, High Efficiency Microchannel Sabatier Reactor Project

    Data.gov (United States)

    National Aeronautics and Space Administration — A Microchannel Sabatier Reactor System (MSRS) consisting of cross connected arrays of isothermal or graded temperature reactors is proposed. The reactor array...

  4. Chronic multichannel neural recordings from soft regenerative microchannel electrodes during gait.

    Science.gov (United States)

    Musick, Katherine M; Rigosa, Jacopo; Narasimhan, Shreya; Wurth, Sophie; Capogrosso, Marco; Chew, Daniel J; Fawcett, James W; Micera, Silvestro; Lacour, Stéphanie P

    2015-09-24

    Reliably interfacing a nerve with an electrode array is one of the approaches to restore motor and sensory functions after an injury to the peripheral nerve. Accomplishing this with current technologies is challenging as the electrode-neuron interface often degrades over time, and surrounding myoelectric signals contaminate the neuro-signals in awake, moving animals. The purpose of this study was to evaluate the potential of microchannel electrode implants to monitor over time and in freely moving animals, neural activity from regenerating nerves. We designed and fabricated implants with silicone rubber and elastic thin-film metallization. Each implant carries an eight-by-twelve matrix of parallel microchannels (of 120 × 110 μm(2) cross-section and 4 mm length) and gold thin-film electrodes embedded in the floor of ten of the microchannels. After sterilization, the soft, multi-lumen electrode implant is sutured between the stumps of the sciatic nerve. Over a period of three months and in four rats, the microchannel electrodes recorded spike activity from the regenerating sciatic nerve. Histology indicates mini-nerves formed of axons and supporting cells regenerate robustly in the implants. Analysis of the recorded spikes and gait kinematics over the ten-week period suggests firing patterns collected with the microchannel electrode implant can be associated with different phases of gait.

  5. Chronic multichannel neural recordings from soft regenerative microchannel electrodes during gait

    Science.gov (United States)

    Musick, Katherine M.; Rigosa, Jacopo; Narasimhan, Shreya; Wurth, Sophie; Capogrosso, Marco; Chew, Daniel J.; Fawcett, James W.; Micera, Silvestro; Lacour, Stéphanie P.

    2015-09-01

    Reliably interfacing a nerve with an electrode array is one of the approaches to restore motor and sensory functions after an injury to the peripheral nerve. Accomplishing this with current technologies is challenging as the electrode-neuron interface often degrades over time, and surrounding myoelectric signals contaminate the neuro-signals in awake, moving animals. The purpose of this study was to evaluate the potential of microchannel electrode implants to monitor over time and in freely moving animals, neural activity from regenerating nerves. We designed and fabricated implants with silicone rubber and elastic thin-film metallization. Each implant carries an eight-by-twelve matrix of parallel microchannels (of 120 × 110 μm2 cross-section and 4 mm length) and gold thin-film electrodes embedded in the floor of ten of the microchannels. After sterilization, the soft, multi-lumen electrode implant is sutured between the stumps of the sciatic nerve. Over a period of three months and in four rats, the microchannel electrodes recorded spike activity from the regenerating sciatic nerve. Histology indicates mini-nerves formed of axons and supporting cells regenerate robustly in the implants. Analysis of the recorded spikes and gait kinematics over the ten-week period suggests firing patterns collected with the microchannel electrode implant can be associated with different phases of gait.

  6. Aluminum Nitride Micro-Channels Grown via Metal Organic Vapor Phase Epitaxy for MEMs Applications

    Energy Technology Data Exchange (ETDEWEB)

    Rodak, L.E.; Kuchibhatla, S.; Famouri, P.; Ting, L.; Korakakis, D.

    2008-01-01

    Aluminum nitride (AlN) is a promising material for a number of applications due to its temperature and chemical stability. Furthermore, AlN maintains its piezoelectric properties at higher temperatures than more commonly used materials, such as Lead Zirconate Titanate (PZT) [1, 2], making AlN attractive for high temperature micro and nanoelectromechanical (MEMs and NEMs) applications including, but not limited to, high temperature sensors and actuators, micro-channels for fuel cell applications, and micromechanical resonators. This work presents a novel AlN micro-channel fabrication technique using Metal Organic Vapor Phase Epitaxy (MOVPE). AlN easily nucleates on dielectric surfaces due to the large sticking coefficient and short diffusion length of the aluminum species resulting in a high quality polycrystalline growth on typical mask materials, such as silicon dioxide and silicon nitride [3,4]. The fabrication process introduced involves partially masking a substrate with a silicon dioxide striped pattern and then growing AlN via MOVPE simultaneously on the dielectric mask and exposed substrate. A buffered oxide etch is then used to remove the underlying silicon dioxide and leave a free standing AlN micro-channel. The width of the channel has been varied from 5 ìm to 110 ìm and the height of the air gap from 130 nm to 800 nm indicating the stability of the structure. Furthermore, this versatile process has been performed on (111) silicon, c-plane sapphire, and gallium nitride epilayers on sapphire substrates. Reflection High Energy Electron Diffraction (RHEED), Atomic Force Microscopy (AFM), and Raman measurements have been taken on channels grown on each substrate and indicate that the substrate is influencing the growth of the AlN micro-channels on the SiO2 sacrificial layer.

  7. New Developments in the Position Sensitive Detectors Based on Microchannel Plates

    Science.gov (United States)

    Tremsin, A. S.; Siegmund, O. H. W.

    2002-11-01

    We report on the latest developments in position sensitive photon counting detectors based on microchannel plates. Substantial improvement of the spatial resolution was achieved with introduction of new readout technology, namely crossed strip (XS) anode, and corresponding processing electronics. The spatial resolution of XS readout appeared to be as small as ~3-4 μm FWHM. Reduction of the total detector gain (down to 106 and potentially lower) without compromising the spatial accuracy allows detector operation at much higher local and global counting rates since the microchannel recharge time becomes smaller. Recent developments of novel microchannel plate technologies provide basis for substantial increase of the spectral sensitivity and quantum efficiency of MCP detectors. We have tested a number of new Silicon micromachined MCPs The new MCP technologies should allow deposition of completely new photocathode materials directly on the front surface of microchannel plates (opaque photocathodes). Opposite to standard glass MCPs new Silicon MCPs can sustain high temperatures (-800 C°) required for the photocathode deposition and activation processes.

  8. Monolithic ionizing particle detector based on active matrix of functionally integrated structures

    Energy Technology Data Exchange (ETDEWEB)

    Murashev, V.N. [National University of Science and Technology “MISIS” (Russian Federation); Legotin, S.A., E-mail: serlego@mail.ru [National University of Science and Technology “MISIS” (Russian Federation); Karmanov, D.E. [Lomonosov Moscow State University, Skobeltsyn Institute of Nuclear Physics (MSU SINP) (Russian Federation); Baryshnikov, F.M.; Didenko, S.I. [National University of Science and Technology “MISIS” (Russian Federation)

    2014-02-15

    Highlights: • A new type of monolithic silicon position detector is presented. • An operating principle, design and technology of the detector are described. • Calculated estimations of the detecting efficiency are carried out. • Experimental results of alpha-particle and electron detection are shown. -- Abstract: An operating principle, design and technology of a new type of the monolithic silicon position detector (MSPD) for registration of ionizing particles and photons are described. The detector represents a specialized monolithic silicon VLSI that contains a two-dimensional detecting matrix of active functionally integrated bipolar structures and peripheral electronic circuitry for signal amplification and processing. This paper presents experimental results of α-particles and electrons detection with position accuracy and operation speed better than 12.5 μm and 1 ns, respectively. The given estimations show the capabilities of this detector and its advantages in comparison with analogs.

  9. Bioaffinity chromatography on monolithic supports

    NARCIS (Netherlands)

    Tetala, K.K.R.; Beek, van T.A.

    2010-01-01

    Affinity chromatography on monolithic supports is a powerful analytical chemical platform because it allows for fast analyses, small sample volumes, strong enrichment of trace biomarkers and applications in microchips. In this review, the recent research using monolithic materials in the field of bi

  10. Bioaffinity chromatography on monolithic supports

    NARCIS (Netherlands)

    Tetala, K.K.R.; Beek, van T.A.

    2010-01-01

    Affinity chromatography on monolithic supports is a powerful analytical chemical platform because it allows for fast analyses, small sample volumes, strong enrichment of trace biomarkers and applications in microchips. In this review, the recent research using monolithic materials in the field of bi

  11. Interplay between Nanochannel and Microchannel Resistances.

    Science.gov (United States)

    Green, Yoav; Eshel, Ran; Park, Sinwook; Yossifon, Gilad

    2016-04-13

    Current nanochannel system paradigm commonly neglects the role of the interfacing microchannels and assumes that the ohmic electrical response of a microchannel-nanochannel system is solely determined by the geometric properties of the nanochannel. In this work, we demonstrate that the overall response is determined by the interplay between the nanochannel resistance and various microchannel attributed resistances. Our experiments confirm a recent theoretical prediction that in contrast to what was previously assumed at very low concentrations the role of the interfacing microchannels on the overall resistance becomes increasingly important. We argue that the current nanochannel-dominated conductance paradigm can be replaced with a more correct and intuitive microchannel-nanochannel-resistance-model-based paradigm.

  12. Design of monoliths through their mechanical properties.

    Science.gov (United States)

    Podgornik, Aleš; Savnik, Aleš; Jančar, Janez; Krajnc, Nika Lendero

    2014-03-14

    Chromatographic monoliths have several interesting properties making them attractive supports for analytics but also for purification, especially of large biomolecules and bioassemblies. Although many of monolith features were thoroughly investigated, there is no data available to predict how monolith mechanical properties affect its chromatographic performance. In this work, we investigated the effect of porosity, pore size and chemical modification on methacrylate monolith compression modulus. While a linear correlation between pore size and compression modulus was found, the effect of porosity was highly exponential. Through these correlations it was concluded that chemical modification affects monolith porosity without changing the monolith skeleton integrity. Mathematical model to describe the change of monolith permeability as a function of monolith compression modulus was derived and successfully validated for monoliths of different geometries and pore sizes. It enables the prediction of pressure drop increase due to monolith compressibility for any monolith structural characteristics, such as geometry, porosity, pore size or mobile phase properties like viscosity or flow rate, based solely on the data of compression modulus and structural data of non-compressed monolith. Furthermore, it enables simple determination of monolith pore size at which monolith compressibility is the smallest and the most robust performance is expected. Data of monolith compression modulus in combination with developed mathematical model can therefore be used for the prediction of monolith permeability during its implementation but also to accelerate the design of novel chromatographic monoliths with desired hydrodynamic properties for particular application.

  13. Compact Ceramic Microchannel Heat Exchangers

    Energy Technology Data Exchange (ETDEWEB)

    Lewinsohn, Charles [Ceramatec, Inc., Salt Lake City, UT (United States)

    2016-10-31

    The objective of the proposed work was to demonstrate the feasibility of a step change in power plant efficiency at a commercially viable cost, by obtaining performance data for prototype, compact, ceramic microchannel heat exchangers. By performing the tasks described in the initial proposal, all of the milestones were met. The work performed will advance the technology from Technology Readiness Level 3 (TRL 3) to Technology Readiness Level 4 (TRL 4) and validate the potential of using these heat exchangers for enabling high efficiency solid oxide fuel cell (SOFC) or high-temperature turbine-based power plants. The attached report will describe how this objective was met. In collaboration with The Colorado School of Mines (CSM), specifications were developed for a high temperature heat exchanger for three commercial microturbines. Microturbines were selected because they are a more mature commercial technology than SOFC, they are a low-volume and high-value target for market entry of high-temperature heat exchangers, and they are essentially scaled-down versions of turbines used in utility-scale power plants. Using these specifications, microchannel dimensions were selected to meet the performance requirements. Ceramic plates were fabricated with microchannels of these dimensions. The plates were tested at room temperature and elevated temperature. Plates were joined together to make modular, heat exchanger stacks that were tested at a variety of temperatures and flow rates. Although gas flow rates equivalent to those in microturbines could not be achieved in the laboratory environment, the results showed expected efficiencies, robust operation under significant temperature gradients at high temperature, and the ability to cycle the stacks. Details of the methods and results are presented in this final report.

  14. Overlimiting current in a microchannel

    CERN Document Server

    Dydek, E Victoria; Rubinstein, Isaak; Deng, D S; Mani, Ali; Bazant, Martin Z

    2011-01-01

    We revisit the classical problem of diffusion-limited ion transport to a membrane (or electrode) by considering the effects of charged side walls. Using simple mathematical models and numerical simulations, we identify three basic mechanisms for over-limiting current in a microchannel: (i) {\\it surface conduction} carried by excess counterions, which dominates for very thin channels, (ii) convection by {\\it electro-osmotic flow} on the side walls, which dominates for thicker channels and transitions to (iii) {\\it electro-osmotic instability} on the membrane end in very thick channels. These intriguing electrokinetic phenomena may find applications in biological separations, water desalination, and electrochemical energy storage.

  15. Flow boiling in expanding microchannels

    CERN Document Server

    Alam, Tamanna

    2017-01-01

    This Brief presents an up to date summary of details of the flow boiling heat transfer, pressure drop and instability characteristics; two phase flow patterns of expanding microchannels. Results obtained from the different expanding microscale geometries are presented for comparison and addition to that, comparison with literatures is also performed. Finally, parametric studies are performed and presented in the brief. The findings from this study could help in understanding the complex microscale flow boiling behavior and aid in the design and implementation of reliable compact heat sinks for practical applications.

  16. Distributive Distillation Enabled by Microchannel Process Technology

    Energy Technology Data Exchange (ETDEWEB)

    Arora, Ravi

    2013-01-22

    The application of microchannel technology for distributive distillation was studied to achieve the Grand Challenge goals of 25% energy savings and 10% return on investment. In Task 1, a detailed study was conducted and two distillation systems were identified that would meet the Grand Challenge goals if the microchannel distillation technology was used. Material and heat balance calculations were performed to develop process flow sheet designs for the two distillation systems in Task 2. The process designs were focused on two methods of integrating the microchannel technology 1) Integrating microchannel distillation to an existing conventional column, 2) Microchannel distillation for new plants. A design concept for a modular microchannel distillation unit was developed in Task 3. In Task 4, Ultrasonic Additive Machining (UAM) was evaluated as a manufacturing method for microchannel distillation units. However, it was found that a significant development work would be required to develop process parameters to use UAM for commercial distillation manufacturing. Two alternate manufacturing methods were explored. Both manufacturing approaches were experimentally tested to confirm their validity. The conceptual design of the microchannel distillation unit (Task 3) was combined with the manufacturing methods developed in Task 4 and flowsheet designs in Task 2 to estimate the cost of the microchannel distillation unit and this was compared to a conventional distillation column. The best results were for a methanol-water separation unit for the use in a biodiesel facility. For this application microchannel distillation was found to be more cost effective than conventional system and capable of meeting the DOE Grand Challenge performance requirements.

  17. Single crystalline mesoporous silicon nanowires

    Energy Technology Data Exchange (ETDEWEB)

    Hochbaum, Allon; Dargas, Daniel; Hwang, Yun Jeong; Yang, Peidong

    2009-08-18

    Herein we demonstrate a novel electroless etching synthesis of monolithic, single-crystalline, mesoporous silicon nanowire arrays with a high surface area and luminescent properties consistent with conventional porous silicon materials. The photoluminescence of these nanowires suggest they are composed of crystalline silicon with small enough dimensions such that these arrays may be useful as photocatalytic substrates or active components of nanoscale optoelectronic devices. A better understanding of this electroless route to mesoporous silicon could lead to facile and general syntheses of different narrow bandgap semiconductor nanostructures for various applications.

  18. Highly tailorable thiol-ene based emulsion-templated monoliths

    DEFF Research Database (Denmark)

    Lafleur, J. P.; Kutter, J. P.

    2014-01-01

    The attractive surface properties of thiol-ene polymers combined with their ease of processing make them ideal substrates in many bioanalytical applications. We report the synthesis of highly tailorable emulsion-templated porous polymers and beads in microfluidic devices based on off-stoichiometr......The attractive surface properties of thiol-ene polymers combined with their ease of processing make them ideal substrates in many bioanalytical applications. We report the synthesis of highly tailorable emulsion-templated porous polymers and beads in microfluidic devices based on off......-stoichiometry thiolene chemistry. The method allows monolith synthesis and anchoring inside thiol-ene microchannels in a single step. Variations in the monomer stoichiometric ratios and/or amount of porogen used allow for the creation of extremely varied polymer morphologies, from foam-like materials to dense networks...

  19. Porous polymer monolithic col

    Directory of Open Access Journals (Sweden)

    Lydia Terborg

    2015-05-01

    Full Text Available A new approach has been developed for the preparation of mixed-mode stationary phases to separate proteins. The pore surface of monolithic poly(glycidyl methacrylate-co-ethylene dimethacrylate capillary columns was functionalized with thiols and coated with gold nanoparticles. The final mixed mode surface chemistry was formed by attaching, in a single step, alkanethiols, mercaptoalkanoic acids, and their mixtures on the free surface of attached gold nanoparticles. Use of these mixtures allowed fine tuning of the hydrophobic/hydrophilic balance. The amount of attached gold nanoparticles according to thermal gravimetric analysis was 44.8 wt.%. This value together with results of frontal elution enabled calculation of surface coverage with the alkanethiol and mercaptoalkanoic acid ligands. Interestingly, alkanethiols coverage in a range of 4.46–4.51 molecules/nm2 significantly exceeded that of mercaptoalkanoic acids with 2.39–2.45 molecules/nm2. The mixed mode character of these monolithic stationary phases was for the first time demonstrated in the separations of proteins that could be achieved in the same column using gradient elution conditions typical of reverse phase (using gradient of acetonitrile in water and ion exchange chromatographic modes (applying gradient of salt in water, respectively.

  20. Micromachined strain gauges for the determination of liquid flow friction coefficients in microchannels

    Science.gov (United States)

    Baviere, R.; Ayela, F.

    2004-02-01

    In this research program, we have performed and tested cupro-nickel (Cu-Ni) strain gauges micromachined on different sorts of silicon nitride (Si3N4) membranes. The design of the gauges obeys an electrical Wheatstone bridge configuration. We have found a good agreement between the expected electromechanical response of the bridge and the experimental signals. The results have displayed sensitivity to static pressure ranging from 50 to 100 µV V-1 bar-1 as a function of the thickness and of the diameter of the membranes. This is part of a study devoted to determining liquid flow friction coefficients in silicon-Pyrex microchannels. Preliminary attempts (Reynolds number up to 300) made using global pressure measurements and with very simple local pressure probes are discussed. Further experiments using Cu-Ni strain gauges are described. Their micromachining, characterization and integration along silicon microchannels are presented. These sensors permitted us to perform the first local and reliable pressure drop measurements in a 7.5 µm deep microchannel. The results are in good agreement with the classical laminar theory for a Reynolds number ranging from 0.2 to 3.

  1. Biobased monoliths for adenovirus purification.

    Science.gov (United States)

    Fernandes, Cláudia S M; Gonçalves, Bianca; Sousa, Margarida; Martins, Duarte L; Barroso, Telma; Pina, Ana Sofia; Peixoto, Cristina; Aguiar-Ricardo, Ana; Roque, A Cecília A

    2015-04-01

    Adenoviruses are important platforms for vaccine development and vectors for gene therapy, increasing the demand for high titers of purified viral preparations. Monoliths are macroporous supports regarded as ideal for the purification of macromolecular complexes, including viral particles. Although common monoliths are based on synthetic polymers as methacrylates, we explored the potential of biopolymers processed by clean technologies to produce monoliths for adenovirus purification. Such an approach enables the development of disposable and biodegradable matrices for bioprocessing. A total of 20 monoliths were produced from different biopolymers (chitosan, agarose, and dextran), employing two distinct temperatures during the freezing process (-20 °C and -80 °C). The morphological and physical properties of the structures were thoroughly characterized. The monoliths presenting higher robustness and permeability rates were further analyzed for the nonspecific binding of Adenovirus serotype 5 (Ad5) preparations. The matrices presenting lower nonspecific Ad5 binding were further functionalized with quaternary amine anion-exchange ligand glycidyltrimethylammonium chloride hydrochloride by two distinct methods, and their performance toward Ad5 purification was assessed. The monolith composed of chitosan and poly(vinyl) alcohol (50:50) prepared at -80 °C allowed 100% recovery of Ad5 particles bound to the support. This is the first report of the successful purification of adenovirus using monoliths obtained from biopolymers processed by clean technologies.

  2. Effect of Running Parameters on Flow Boiling Instabilities in Microchannels.

    Science.gov (United States)

    Zong, Lu-Xiang; Xu, Jin-Liang; Liu, Guo-Hua

    2015-04-01

    Flow boiling instability (FBI) in microchannels is undesirable because they can induce the mechanical vibrations and disturb the heat transfer characteristics. In this study, the synchronous optical visualization experimental system was set up. The pure acetone liquid was used as the working fluid, and the parallel triangle silicon microchannel heat sink was designed as the experimental section. With the heat flux ranging from 0-450 kW/m2 the microchannel demand average pressure drop-heater length (Δp(ave)L) curve for constant low mass flux, and the demand pressure drop-mass flux (Δp(ave)G) curve for constant length on main heater surface were obtained and studied. The effect of heat flux (q = 188.28, 256.00, and 299.87 kW/m2), length of main heater surface (L = 4.5, 6.25, and 8.00 mm), and mass flux (G = 188.97, 283.45, and 377.94 kg/m2s) on pressure drops (Ap) and temperatures at the central point of the main heater surface (Twc) were experimentally studied. The results showed that, heat flux, length of the main heater surface, and mass flux were identified as the important parameters to the boiling instability process. The boiling incipience (TBI) and critical heat flux (CHF) were early induced for the lower mass flux or the main heater surface with longer length. With heat flux increasing, the pressure drops were linearly and slightly decreased in the single liquid region but increased sharply in the two phase flow region, in which the flow boiling instabilities with apparent amplitude and long period were more easily triggered at high heat flux. Moreover, the system pressure was increased with the increase of the heat flux.

  3. Non-destructive 3D characterization of microchannels

    Science.gov (United States)

    Heikkinen, Ville; Nolvi, Anton; Kassamakov, Ivan; Grigoras, Kestutis; Franssila, Sami; Hæggström, Edward

    2012-10-01

    Microfluidic devices allow experimentation in smaller space using small amounts of liquid, resulting in improved reaction rates, cheaper equipment, reduced amount of expensive reagents. Very precise channel shape measurements are needed to assure the designed flow pattern. Several 3D imaging devices provide the necessary precision but typically they cannot image inside closed devices. Hence it is difficult to measure the shape of a microfluidic channel without destroying it. We fabricated and investigated samples with different microchannels. Several types of microfluidic channels were prepared in silicon wafer with a subsequent covering by bonding glass wafer on top. Microchannels in polymer have been done using epoxy-type photoresist SU-8. The internal geometry of the channels was measured using a Scanning White Light Interferometer (SWLI) equipped with optics that compensates for the effects of the top glass of the channels. The geometry of the interior of the channels can be measured with a precision similar to surface layer SWLI measurements without destroying the channels.

  4. Analysis of microchannel heat sink performance using nanofluids

    Energy Technology Data Exchange (ETDEWEB)

    Chein, Reiyu; Huang, Guanming [Department of Mechanical Engineering, National Chung Hsing University, 250 Kuo-Kuang Rd., Taichung City 402 (China)

    2005-12-01

    In this study, silicon microchannel heat sink performance using nanofluids as coolants was analyzed. The nanofluid was a mixture of pure water and nanoscale Cu particles with various volume fractions. The heat transfer and friction coefficients required in the analysis were based on theoretical models and experimental correlations. In the theoretical model, nanofluid was treated as a single-phase fluid. In the experimental correlation, thermal dispersion due to particle random motion was included. The microchannel heat sink performances for two specific geometries, one with W{sub ch}=W{sub fin}=100 {mu}m and L{sub ch}=300 {mu}m, the other with W{sub ch}=W{sub fin}=57 {mu}m and L{sub ch}=365 {mu}m, were examined. Because of the increased thermal conductivity and thermal dispersion effects, it was found that the performances were greatly improved for these two specific geometries when nanofluids were used as the coolants. In addition to heat transfer enhancement, the existence of nanoparticles in the fluid did not produce extra pressure drop because of small particle size and low particle volume fraction. (author)

  5. Laminar Drag Reduction in Microchannels Using Ultrahydrophobic Surfaces

    Science.gov (United States)

    Ou, Jia; Perot, Blair; Rothstein, Jonathan

    2003-11-01

    In devices where the fluid flow is laminar, there are currently no methods for reducing drag. We will present a series of experiments which demonstrate a 20-30% drag reduction for the flow of water through microchannels using hydrophobic surfaces with micron sized roughness. These 'ultrahydrophobic' surfaces are fabricated using photolithography to etch microposts and microridges with specific size, spacing and arrangement into silicon. The surfaces are then reacted with an organosilane to make them hydrophobic. The resulting surfaces have contact angles greater than 150 degrees. Pressure drop measurements are made for a series of ultrahydrophobic surface patterns, flow rates and microchannel heights. Pressure drop measurements across hydrophobic smooth surfaces are found to correlate precisely with theory while the drag reduction observed for the flow across these ultrahydrophobic surfaces is found to increase with increasing micropost spacing and decreasing micropost area. A physical model will be presented which explains the drag reduction in terms of a shear-free air-water interface between microposts supported by surface tension. Confirmation of the model will be presented with optical measurements of the displacement of the air-water interface under flow.

  6. Planar, monolithically integrated coil

    NARCIS (Netherlands)

    Roozeboom, F.; Reefman, D.; Klootwijk, J.H.; Tiemeijer, L.F.; Ruigrok, J.

    2013-01-01

    The present invention provides a means to integrate planar coils on silicon, while providing a high inductance. This high inductance is achieved through a special back- and front sided shielding of a material. In many applications, high-value inductors are a necessity. In particular, this holds for

  7. Next Generation Microchannel Heat Exchangers

    CERN Document Server

    Ohadi, Michael; Dessiatoun, Serguei; Cetegen, Edvin

    2013-01-01

    In Next Generation Microchannel Heat Exchangers, the authors’ focus on the new generation highly efficient heat exchangers and presentation of novel data and technical expertise not available in the open literature.  Next generation micro channels offer record high heat transfer coefficients with pressure drops much less than conventional micro channel heat exchangers. These inherent features promise fast penetration into many mew markets, including high heat flux cooling of electronics, waste heat recovery and energy efficiency enhancement applications, alternative energy systems, as well as applications in mass exchangers and chemical reactor systems. The combination of up to the minute research findings and technical know-how make this book very timely as the search for high performance heat and mass exchangers that can cut costs in materials consumption intensifies.

  8. Active Mixing in a Microchannel

    Science.gov (United States)

    Guo, Chun-Hai; Tan, Jun-Jie; Ren, Deng-Feng; Zhang, Yu-Cheng; Wang, Fu-Hua

    2010-11-01

    We investigate a minute magneto hydro-dynamic mixer with relatively rapid mixing enhancement experimentally and analytically. The mixer is fabricated with brass and polymethyl methacrylate (PMMA) layers. A secondary flow is generated by using the Lorentz force in the fluids. The efficiency of mixing is greatly improved due to the large increase of the contact area between two mixing fluids. The micro particle image velocimetry technique is employed to measure the fluid flow characteristics in the micro-channel. Numerical simulation is performed based on the theoretical model of the computational fluid dynamics and the electromagnetic field theory. The experimental results are in good agreement with the numerical results, which indicates that the mixing area is enlarged by the driving of Lorentz force and the mixing can be enhanced.

  9. Performances of thermoelectric cooler integrated with microchannel heat sinks

    Energy Technology Data Exchange (ETDEWEB)

    Reiyu Chein; Yehong Chen [National Chung Hsing University, Taichung (Taiwan). Department of Mechanical Engineering

    2005-09-01

    In this study, experimental and theoretical studies on thermoelectric cooler (TEC) performance for cooling a refrigerated object (water in a tank) were performed. Microchannel heat sinks fabricated with etched silicon wafers were employed on the TEC hot side to dissipate heat. The measurements show that the temperature of the refrigerated object decreased with time. A theoretical model based on a lumped system was established to predict the transient behavior of the variation in temperature for the refrigerated object with time. The theoretical predicted temperature variation was in good agreement with the measured data. The relationship among the heat sink thermal resistances, TEC electric current input and minimum refrigerated objected temperature was examined based on the theoretical model. The calculated minimum temperatures were showed for the several cases of heat sink thermal resistance on the TEC hot side and electric current input. The minimum temperature can be obtained by increasing the electrical current input and decreasing the heat sink thermal resistance. (author)

  10. Silicon Micromachined Vertical Structures for Nanoparticle Separation

    NARCIS (Netherlands)

    Shen, C.

    2011-01-01

    In this thesis we described a new approach to design, fabricate, package and test three silicon based porous vertical structures for nanoparticle separations. These vertical structures stand in between two microfluidic channels. In these walls nano channels that connect the two adjacent microchannel

  11. Microchannel Plate Imaging Detectors for the Ultraviolet

    Science.gov (United States)

    Siegmund, O. H. W.; Gummin, M. A.; Stock, J.; Marsh, D.

    1992-01-01

    There has been significant progress over the last few years in the development of technologies for microchannel plate imaging detectors in the Ultraviolet (UV). Areas where significant developments have occurred include enhancements of quantum detection efficiency through improved photocathodes, advances in microchannel plate performance characteristics, and development of high performance image readout techniques. The current developments in these areas are summarized, with their applications in astrophysical instrumentation.

  12. A review of entropy generation in microchannels

    Directory of Open Access Journals (Sweden)

    Mohamed M Awad

    2015-12-01

    Full Text Available In this study, a critical review of thermodynamic optimum of microchannels based on entropy generation analysis is presented. Using entropy generation analysis as evaluation parameter of microchannels has been reported by many studies in the literature. In these studies, different working fluids such as nanofluids, air, water, engine oil, aniline, ethylene glycol, and non-Newtonian fluids have been used. For the case of nanofluids, “nanoparticles” has been used in various kinds such as Al2O3 and Cu, and “base fluid” has been used in various kinds such as water and ethylene glycol. Furthermore, studies on thermodynamic optimum of microchannels based on entropy generation analysis are summarized in a table. At the end, recommendations of future work for thermodynamic optimum of microchannels based on entropy generation analysis are given. As a result, this article can not only be used as the starting point for the researcher interested in entropy generation in microchannels, but it also includes recommendations for future studies on entropy generation in microchannels.

  13. A nanofabricated, monolithic, path-separated electron interferometer

    CERN Document Server

    Agarwal, Akshay; Hobbs, Richard; van Dyck, Dirk; Berggren, Karl K

    2016-01-01

    We report a self-aligned, monolithic electron interferometer, consisting of two 45 nm thick silicon layers separated by 20 $\\mu$m. This interferometer was fabricated from a single crystal silicon cantilever on a transmission electron microscope grid by gallium focused ion-beam milling. Using this interferometer, we demonstrate beam path-separation, and obtain interference fringes in a Mach-Zehnder geometry, in an unmodified 200 kV transmission electron microscope. The fringes have a period of 0.32 nm, which corresponds to the $\\left[\\bar{1}\\bar{1}1\\right]$ lattice planes of silicon, and a maximum contrast of 15 %. This design can potentially be scaled to millimeter-scale, and used in electron holography. It can also be applied to perform fundamental physics experiments, such as interaction-free measurement with electrons.

  14. Detection of ochratoxin A in beer samples with a label-free monolithically integrated optoelectronic biosensor

    NARCIS (Netherlands)

    Pagkali, Varvara; Petrou, Panagiota S.; Salapatas, Alexandros; Makarona, Eleni; Peters, Jeroen; Haasnoot, Willem; Jobst, Gerhard; Economou, Anastasios; Misiakos, Konstantinos; Raptis, Ioannis; Kakabakos, Sotirios E.

    2016-01-01

    An optical biosensor for label-free detection of ochratoxin A (OTA) in beer samples is presented. The biosensor consists of an array of ten Mach-Zehnder interferometers (MZIs) monolithically integrated along with their respective broad-band silicon light sources on the same Si chip (37mm2

  15. Detection of ochratoxin A in beer samples with a label-free monolithically integrated optoelectronic biosensor

    NARCIS (Netherlands)

    Pagkali, Varvara; Petrou, Panagiota S.; Salapatas, Alexandros; Makarona, Eleni; Peters, Jeroen; Haasnoot, Willem; Jobst, Gerhard; Economou, Anastasios; Misiakos, Konstantinos; Raptis, Ioannis; Kakabakos, Sotirios E.

    2017-01-01

    An optical biosensor for label-free detection of ochratoxin A (OTA) in beer samples is presented. The biosensor consists of an array of ten Mach-Zehnder interferometers (MZIs) monolithically integrated along with their respective broad-band silicon light sources on the same Si chip (37mm2

  16. A NEW MECHANISM OF SPONTANEOUS BREAKAGE OF TEMPERED GLASS——MONOLITHIC SILICON PARTICLES%钢化玻璃自爆机理的新发现——单质硅微粒引裂

    Institute of Scientific and Technical Information of China (English)

    包亦望; 刘立忠; 韩松; 石新勇; 杨建军

    2007-01-01

    It has been discovered and demonstrated, via scanning electron microscope examination on 6 samples of broken glasses,that one important cause for the spontaneous breakage in tempered glass occurs as a result of the single-phase polycrystalline silicon particles, rather than simply the nickel sulfide (NiS) particles that are commonly recognized to be the main cause for the spontaneous breakage. The mechanism of the spontaneous breakage resulting from these silicon particles was analyzed by using the finite element method. The calculation indicates that the crack initiation and extension on a whole glass sample is imputed to the tensile tangent stress in the glass near the silicon particle. The risk of spontaneous breakage, as caused by silicon particles in a heat-treated glass,might increase with a decreasing temperature.%通过对6块玻璃自爆残片的电镜观察和成分分析,发现并证明了引起钢化玻璃自爆的主要原因不仅仅是传统认识中的硫化镍(NiS)微粒,很多情况是由单质硅微粒引起的.进一步对单质硅微粒引起自爆的力学机理进行了分析和有限元模拟.结果显示:由于单质硅微粒周边玻璃的切向应力过大从而引起局部拉伸破坏并导致整体破裂,降温过程可以使这种应力增加并加大破裂危险.

  17. Single crystalline mesoporous silicon nanowires

    Energy Technology Data Exchange (ETDEWEB)

    Hochbaum, A.I.; Gargas, Daniel; Jeong Hwang, Yun; Yang, Peidong

    2009-08-04

    Herein we demonstrate a novel electroless etching synthesis of monolithic, single-crystalline, mesoporous silicon nanowire arrays with a high surface area and luminescent properties consistent with conventional porous silicon materials. These porous nanowires also retain the crystallographic orientation of the wafer from which they are etched. Electron microscopy and diffraction confirm their single-crystallinity and reveal the silicon surrounding the pores is as thin as several nanometers. Confocal fluorescence microscopy showed that the photoluminescence (PL) of these arrays emanate from the nanowires themselves, and their PL spectrum suggests that these arrays may be useful as photocatalytic substrates or active components of nanoscale optoelectronic devices.

  18. Tuning bubbly structures in microchannels.

    Science.gov (United States)

    Vuong, Sharon M; Anna, Shelley L

    2012-06-01

    Foams have many useful applications that arise from the structure and size distribution of the bubbles within them. Microfluidics allows for the rapid formation of uniform bubbles, where bubble size and volume fraction are functions of the input gas pressure, liquid flow rate, and device geometry. After formation, the microchannel confines the bubbles and determines the resulting foam structure. Bubbly structures can vary from a single row ("dripping"), to multiple rows ("alternating"), to densely packed bubbles ("bamboo" and dry foams). We show that each configuration arises in a distinct region of the operating space defined by bubble volume and volume fraction. We describe the boundaries between these regions using geometric arguments and show that the boundaries are functions of the channel aspect ratio. We compare these geometric arguments with foam structures observed in experiments using flow-focusing, T-junction, and co-flow designs to generate stable nitrogen bubbles in aqueous surfactant solution and stable droplets in oil containing dissolved surfactant. The outcome of this work is a set of design parameters that can be used to achieve desired foam structures as a function of device geometry and experimental control parameters.

  19. Streaming potential of superhydrophobic microchannels.

    Science.gov (United States)

    Park, Hung Mok; Kim, Damoa; Kim, Se Young

    2016-12-09

    For the purpose of gaining larger streaming potential, it has been suggested to employ superhydrophobic microchannels with a large velocity slip. There are two kinds of superhydrophobic surfaces, one having a smooth wall with a large Navier slip coefficient caused by the hydrophobicity of the wall material, and the other having a periodic array of no- shear slots of air pockets embedded in a nonslip wall. The electrokinetic flows over these two superhydrophobic surfaces are modelled using the Navier-Stokes equation and convection-diffusion equations of the ionic species. The Navier slip coefficient of the first kind surfaces and the no-shear slot ratio of the second kind surfaces are similar in the sense that the volumetric flow rate increases as these parameter values increase. However, although the streaming potential increases monotonically with respect to the Navier slip coefficient, it reaches a maximum and afterward decreases as the no-shear ratio increases. The results of the present investigation imply that the characterization of superhydrophobic surfaces employing only the measurement of volumetric flow rate against pressure drop is not appropriate and the fine structure of the superhydrophobic surfaces must be verified before predicting the streaming potential and electrokinetic flows accurately.

  20. Numerical simulation of electroosmotic flow in hydrophobic microchannels

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    Electroosmotic flow(EOF) is a promising way for driving and mixing fluids in microfluidics.For the parallel-plate microchannel with the hydrophobic surface, this paper solved the governing equations using the finite element method(FEM), and the effects of microchannel height, electric strength and ionic concentration on EOF were thus investigated.The simulation indicates that the transient characteristics of EOF are similar in hydrophobic and hydrophilic microchannels, the steady time of EOF is proportional to the square of microchannel height, and the scale is microsecond.EOF velocity is proportional to the electric strength and independent of the channel height, and decreases slowly with the ionic concentration, which is lower than that in hydrophilic microchannel due to the presence of slip length in hydrophobic microchannel.The results can provide valuable insights into the optimal design of microchannel surfaces to achieve accurate EOF control in hydrophobic microchannel.

  1. Experimental Study of Interfacial Friction in NaBH{sub 4} Solution in Microchannel Dehydrogenation Reactor

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Seok Hyun; Hwang, Sueng Sik; Lee, Hee Joon [Kookmin Univ., Seoul (Korea, Republic of)

    2014-02-15

    Sodium borohydride (NaBH{sub 4}) is considered as a secure metal hydride for hydrogen storage and supply. In this study, the interfacial friction of two-phase flow in the dehydrogenation of aqueous NaBH{sub 4} solution in a microchannel with a hydraulic diameter of 461 μm is investigated for designing a dehydrogenation chemical reactor flow passage. Because hydrogen gas is generated by the hydrolysis of NaBH{sub 4} in the presence of a ruthenium catalyst, two different flow phases (aqueous NaBH{sub 4} solution and hydrogen gas) exist in the channel. For experimental studies, a microchannel was fabricated on a silicon wafer substrate, and 100-nm ruthenium catalyst was deposited on three sides of the channel surface. A bubbly flow pattern was observed. The experimental results indicate that the two-phase multiplier increases linearly with the void fraction, which depends on the initial concentration, reaction rate, and flow residence time.

  2. Microchannel cooling of face down bonded chips

    Science.gov (United States)

    Bernhardt, Anthony F.

    1993-01-01

    Microchannel cooling is applied to flip-chip bonded integrated circuits, in a manner which maintains the advantages of flip-chip bonds, while overcoming the difficulties encountered in cooling the chips. The technique is suited to either multichip integrated circuit boards in a plane, or to stacks of circuit boards in a three dimensional interconnect structure. Integrated circuit chips are mounted on a circuit board using flip-chip or control collapse bonds. A microchannel structure is essentially permanently coupled with the back of the chip. A coolant delivery manifold delivers coolant to the microchannel structure, and a seal consisting of a compressible elastomer is provided between the coolant delivery manifold and the microchannel structure. The integrated circuit chip and microchannel structure are connected together to form a replaceable integrated circuit module which can be easily decoupled from the coolant delivery manifold and the circuit board. The coolant supply manifolds may be disposed between the circuit boards in a stack and coupled to supplies of coolant through a side of the stack.

  3. Effects of microchannel geometry on preconcentration intensity in microfluidic chips with straight or convergent-divergent microchannels.

    Science.gov (United States)

    Chen, Chia-Lin; Yang, Ruey-Jen

    2012-03-01

    Preconcentration microfluidic devices are fabricated incorporating straight or convergent-divergent microchannels and hydrogel or Nafion membranes. Sample preconcentration is achieved utilizing concentration-polarization effects. The effects of the microchannel geometry on the preconcentration intensity are systematically examined. It is shown that for the preconcentrator with the straight microchannel, the time required to achieve a satisfactory preconcentration intensity increases with an increasing channel depth. For the convergent-divergent microchannel, the preconcentration intensity increases with a reducing convergent channel width. Comparing the preconcentration performance of the two different microchannel configurations, it is found that for an equivalent width of the main microchannel, the concentration effect in the convergent-divergent microchannel is faster than that in the straight microchannel.

  4. Chemically driven fluid transport in long microchannels

    Science.gov (United States)

    Shen, Mingren; Ye, Fangfu; Liu, Rui; Chen, Ke; Yang, Mingcheng; Ripoll, Marisol

    2016-09-01

    Chemical gradients maintained along surfaces can drive fluid flows by diffusio-osmosis, which become significant at micro- and nano-scales. Here, by means of mesoscopic simulations, we show that a concentration drop across microchannels with periodically inhomogeneous boundary walls can laterally transport fluids over arbitrarily long distances along the microchannel. The driving field is the secondary local chemical gradient parallel to the channel induced by the periodic inhomogeneity of the channel wall. The flow velocity depends on the concentration drop across the channel and the structure and composition of the channel walls, but it is independent of the overall channel length. Our work thus presents new insight into the fluid transport in long microchannels commonly found in nature and is useful for designing novel micro- or nano-fluidic pumps.

  5. An Approximate Model of Microchannel Cooling

    Institute of Scientific and Technical Information of China (English)

    ShipingYu; MingdaoXin

    1994-01-01

    Forced convective heat transfer in micro-rectangular channels can be described by a group of two-dimensional differential equations.These equations take the conduction in microchannel wall along the direction of flow of coolants into account,which are more generalized than those which neglect the conduction.For the same reason,they are suitable particularly for gases-cooled microchannels.With only numerical solution to the equations till today,an approximate analytic solution is derived here,From this solution,a rather simple formula can be introduced further,by which the differences between considering the conduction and neglecting it are easily found.In addition,the reasonableness of the classical fin method is also discussed.An experimental example of air-cooled microchannels is illustrated.

  6. Noisy Transition to Turbulence in Microchannels

    CERN Document Server

    Lissandrello, C; Yakhot, V

    2015-01-01

    Here, we study noisy transition to turbulence in a microchannel. We use a microcantilever sensor embedded in the microchannel wall and perform two sets of experiments in the same microchannel: first, we study transition triggered by the natural imperfections of the walls; subsequently, we study transition under artificially added inlet noise. The two experiments result in random flows in which high-order moments of near-wall fluctuations differ by orders of magnitude. Surprisingly however, the lowest order statistics in both cases appear qualitatively similar and can be described by a proposed noisy Landau equation for a slow mode. The noise, regardless of its origin, regularizes the Landau singularity of the relaxation time and makes transitions driven by different noise sources appear similar.

  7. Entrance Effects in Microchannel Gas Flow

    Institute of Scientific and Technical Information of China (English)

    T. Lewandowski; S. Jebauer; J. Czerwinska; P. Doerffer

    2009-01-01

    Motivation of this work has its origin in the boundary layer control for aeronautics and turbomachinery. For that purpose boundary layer can be modified by perforated plates with holes of specific sizes. The questions which rise in such configuration are related to the existence of optimal size of the holes and the influence of microscale phenomena on the global flow patterns. This paper concentrates on the issue of the entrance effects on the micro-channel flow. It is shown that mass flow rate is only insignificantly influenced by slip effects. Global parameters such as pressure difference and geometrical shape in more pronounced way alter flow behavior. In this paper we concentrate on the numerical investigation of the microchannel flow for Kn < 0.01 and Re < 500. The channel length is finite. Hence, entrance and outlet effects on microchannel flow can be studied.

  8. Online microchannel preconcentrator for carbofuran detection.

    Science.gov (United States)

    Siritham, Charinrat; Thammakhet, Chongdee; Thavarungkul, Panote; Kanatharana, Proespichaya

    2013-01-01

    A simple and rapid online microchannel preconcentrator coupled with an amperometric detection for the analysis of carbofuran using polyethylene glycol coated onto magnetic particle (PEG-magnetic particles) sorbents was developed. This simple-to-prepare microchannel preconcentrator used an external magnet to retain the PEG-magnetic particle sorbents inside the microchannel. Under optimum conditions, the system provided two linear ranges, from 0.01 to 10.0 mg L(-1) and from 10.0 to 130.0 mg L(-1) with a limit of detection of 8.7 ± 0.1 μg L(-1). The microchannel preconcentrator provided very good stability; it can be used for up to 326 consecutive injections of 5.0 mg L(-1) carbofuran with a relative standard deviation of less than 3%. The developed system provided a good microchannel-to-microchannel and a good electrode-to-electrode reproducibility (n = 6, %RSD < 1). It also provided an excellent selectivity when it was tested with two other carbamate pesticides, carbaryl and methomyl, with a 43 and 256 times higher detection sensitivity for carbofuran, respectively. The developed system was successfully applied to detect carbofuran in surface water samples obtained near vegetable plantation areas. The concentrations of carbofuran in these samples were found to be in the range of non-detectable to 0.047 ± 0.001 mg L(-1). The developed system is easy to operate and easy to couple with other analytical instruments and it could be easily adapted for the analysis of other polar organic contaminants.

  9. Silicon Microchannel Plate Large Area UV Detector Project

    Data.gov (United States)

    National Aeronautics and Space Administration — To address the NASA GSFC need for efficient UV photodetectors for NASA missions, such as the follow-on to FUV detectors of the Galaxy Evolution Explorer, Physical...

  10. Silicon Microchannel Plate Large Area UV Detector Project

    Data.gov (United States)

    National Aeronautics and Space Administration — To address the NASA need for high-quantum-efficiency, high-resolution, low-cost photodetectors for the far-UV spectral range, Physical Optics Corporation (POC)...

  11. Acoustophoretic Synchronization of Mammalian Cells in Microchannels

    DEFF Research Database (Denmark)

    Thévoz, P.; Adams, J.D.; Shea, H.

    2010-01-01

    We report the first use of ultrasonic standing waves to achieve cell cycle phase synchronization in mammalian cells in a high-throughput and reagent-free manner. The acoustophoretic cell synchronization (ACS) device utilizes volume-dependent acoustic radiation force within a microchannel...... to selectively purify target cells of desired phase from an asynchronous mixture based on cell cycle-dependent fluctuations in size. We show that ultrasonic separation allows for gentle, scalable, and label-free synchronization with high G1 phase synchrony (84%) and throughput (3 × 106 cells/h per microchannel)....

  12. Acoustophoretic Synchronization of Mammalian Cells in Microchannels

    DEFF Research Database (Denmark)

    Thévoz, P.; Adams, J.D.; Shea, H.

    2010-01-01

    We report the first use of ultrasonic standing waves to achieve cell cycle phase synchronization in mammalian cells in a high-throughput and reagent-free manner. The acoustophoretic cell synchronization (ACS) device utilizes volume-dependent acoustic radiation force within a microchannel...... to selectively purify target cells of desired phase from an asynchronous mixture based on cell cycle-dependent fluctuations in size. We show that ultrasonic separation allows for gentle, scalable, and label-free synchronization with high G1 phase synchrony (84%) and throughput (3 × 106 cells/h per microchannel)....

  13. A new diamond biosensor with integrated graphitic microchannels for detecting quantal exocytic events from chromaffin cells

    CERN Document Server

    Picollo, Federico; Vittone, Ettore; Pasquarelli, Alberto; Carbone, Emilio; Olivero, Paolo; Carabelli, Valentina

    2013-01-01

    The quantal release of catecholamines from neuroendocrine cells is a key mechanism which has been investigated with a broad range of materials and devices, among which carbon-based materials such as carbon fibers, diamond-like carbon, carbon nanotubes and nanocrystalline diamond. In the present work we demonstrate that a MeV-ion-microbeam lithographic technique can be successfully employed for the fabrication of an all-carbon miniaturized cellular bio-sensor based on graphitic micro-channels embedded in a single-crystal diamond matrix. The device was functionally characterized for the in vitro recording of quantal exocytic events from single chromaffin cells, with high sensitivity and signal-to-noise ratio, opening promising perspectives for the realization of monolithic all-carbon cellular biosensors.

  14. Superhydrophobic Porous Silicon Surfaces

    Directory of Open Access Journals (Sweden)

    Paolo NENZI

    2011-12-01

    Full Text Available In this paper, we present an inexpensive technique to produce superhydrophobic surfaces from porous silicon. Superhydrophobic surfaces are a key technology for their ability to reduce friction losses in microchannels and their self cleaning properties. The morphology of a p-type silicon wafer is modified by a electrochemical wet etch to produce pores with controlled size and distribution and coated with a silane hydrophobic layer. Surface morphology is characterized by means of scanning electron microscope images. Large contact angles are observed on such surfaces and the results are compared with classical wetting models (Cassie and Wenzel suggesting a mixed Wenzel-Cassie behavior. The presented technique represents a cost-effective means for friction reduction in microfluidic applications, such as lab-on-a-chip.

  15. A soft microchannel decreases polydispersity of droplet generation.

    Science.gov (United States)

    Pang, Yan; Kim, Hyoungsoo; Liu, Zhaomiao; Stone, Howard A

    2014-10-21

    We study the effect of softness of the microchannel on the process of droplet generation in two-phase flows in a T-junction microchannel. One side of the microchannel has a flexible thin PDMS layer, which vibrates naturally while droplets are generated; the deformation frequency coincides with the frequency of droplet formation. Furthermore, we compare the polydispersity of water-in-oil droplets formed with a microchannel with one soft wall with those formed in a conventional rigid microchannel. We show that deformation of the soft wall reduces the polydispersity in the droplet size.

  16. Inkjet print microchannels based on a liquid template.

    Science.gov (United States)

    Guo, Yuzhen; Li, Lihong; Li, Fengyu; Zhou, Haihua; Song, Yanlin

    2015-04-07

    A simple method to fabricate microchannels is demonstrated based on an inkjet printing liquid template. The morphology of the liquid template can be well controlled by using ink with viscosity sensitive to temperature. The as-prepared Y-shape microchannel is used as a microfluidic reactor for an acylation fluorigenic reaction in a matrix of polydimethylsiloxane (PDMS). Arbitrary modification of the microchannels could be easily realized synchronously with the formation of the microchannels. By grafting polyethylene glycol (PEG) onto the internal surface, an anti-biosorption microchannel is obtained. The facile method will be significant for the fabrication of a microfluidic chip with functional modifications.

  17. In situ Fabrication of Monolithic Copper Azide

    Science.gov (United States)

    Li, Bing; Li, Mingyu; Zeng, Qingxuan; Wu, Xingyu

    2016-04-01

    Fabrication and characterization of monolithic copper azide were performed. The monolithic nanoporous copper (NPC) with interconnected pores and nanoparticles was prepared by decomposition and sintering of the ultrafine copper oxalate. The preferable monolithic NPC can be obtained through decomposition and sintering at 400°C for 30 min. Then, the available monolithic NPC was in situ reacted with the gaseous HN3 for 24 h and the monolithic NPC was transformed into monolithic copper azide. Additionally, the copper particles prepared by electrodeposition were also reacted with the gaseous HN3 under uniform conditions as a comparison. The fabricated monolithic copper azide was characterized by Fourier transform infrared (FTIR), inductively coupled plasma-optical emission spectrometry (ICP-OES), and differential scanning calorimetry (DSC).

  18. Numerical simulation of electroosmotic flow in hydrophobic microchannels

    Institute of Scientific and Technical Information of China (English)

    YANG DaYong; LIU Ying

    2009-01-01

    Electroosmotic flow(EOF)is a promising way for driving and mixing fluids in microfluidics.For the parallel-plate microchannel with the hydrophobic surface,this paper solved the governing equations using the finite element method(FEM),and the effects of microchannel height,electric strength and ionic concentration on EOF were thus investigated.The simulation indicates that the transient characteristics of EOF are similar in hydrophobic and hydrophilic microchannels,the steady time of EOF is proportional to the square of microchannel height,and the scale is microsecond.EOF velocity is proportional to the electric strength and independent of the channel height,and decreases slowly with the ionic concentration,which is lower than that in hydrophilic rnicrochannel due to the presence of slip length in hydrophobic microchannel.The results can provide valuable insights into the optimal design of microchannel surfaces to achieve accurate EOF control in hydrophobic microchannel.

  19. T-load microchannel array and fabrication method

    Science.gov (United States)

    Swierkowski, Stefan P.

    2000-01-01

    A three-dimensional (3-D) T-load for planar microchannel arrays for electrophoresis, for example, which enables sample injection directly onto a plane perpendicular to the microchannels' axis, at their ends. This is accomplished by forming input wells that extend beyond the ends of the microchannel thereby eliminating the right angle connection from the input well into the end of the microchannel. In addition, the T-load input well eases the placement of electrode in or adjacent the well and thus enables very efficient reproducible electrokinetic (ek) injection. The T-load input well eliminates the prior input well/microchannel alignment concerns, since the input well can be drilled after the top and bottom microchannel plates are bonded together. The T-load input well may extend partially or entirely through the bottom microchannel plate which enables more efficient gel and solution flushing, and also enables placement of multiple electrodes to assist in the ek sample injection.

  20. Monolithic active pixel radiation detector with shielding techniques

    Energy Technology Data Exchange (ETDEWEB)

    Deptuch, Grzegorz W.

    2016-09-06

    A monolithic active pixel radiation detector including a method of fabricating thereof. The disclosed radiation detector can include a substrate comprising a silicon layer upon which electronics are configured. A plurality of channels can be formed on the silicon layer, wherein the plurality of channels are connected to sources of signals located in a bulk part of the substrate, and wherein the signals flow through electrically conducting vias established in an isolation oxide on the substrate. One or more nested wells can be configured from the substrate, wherein the nested wells assist in collecting charge carriers released in interaction with radiation and wherein the nested wells further separate the electronics from the sensing portion of the detector substrate. The detector can also be configured according to a thick SOA method of fabrication.

  1. Monolithic active pixel radiation detector with shielding techniques

    Science.gov (United States)

    Deptuch, Grzegorz W.

    2016-09-06

    A monolithic active pixel radiation detector including a method of fabricating thereof. The disclosed radiation detector can include a substrate comprising a silicon layer upon which electronics are configured. A plurality of channels can be formed on the silicon layer, wherein the plurality of channels are connected to sources of signals located in a bulk part of the substrate, and wherein the signals flow through electrically conducting vias established in an isolation oxide on the substrate. One or more nested wells can be configured from the substrate, wherein the nested wells assist in collecting charge carriers released in interaction with radiation and wherein the nested wells further separate the electronics from the sensing portion of the detector substrate. The detector can also be configured according to a thick SOA method of fabrication.

  2. Microfabrication of microchannels for fuel cell plates.

    Science.gov (United States)

    Jang, Ho Su; Park, Dong Sam

    2010-01-01

    Portable electronic devices such as notebook computers, PDAs, cellular phones, etc., are being widely used, and they increasingly need cheap, efficient, and lightweight power sources. Fuel cells have been proposed as possible power sources to address issues that involve energy production and the environment. In particular, a small type of fuel-cell system is known to be suitable for portable electronic devices. The development of micro fuel cell systems can be achieved by the application of microchannel technology. In this study, the conventional method of chemical etching and the mechanical machining method of micro end milling were used for the microfabrication of microchannel for fuel cell separators. The two methods were compared in terms of their performance in the fabrication with regards to dimensional errors, flatness, straightness, and surface roughness. Following microchannel fabrication, the powder blasting technique is introduced to improve the coating performance of the catalyst on the surface of the microchannel. Experimental results show that end milling can remarkably increase the fabrication performance and that surface treatment by powder blasting can improve the performance of catalyst coating.

  3. Continuous steroid biotransformations in microchannel reactors.

    Science.gov (United States)

    Marques, Marco P C; Fernandes, Pedro; Cabral, Joaquim M S; Znidaršič-Plazl, Polona; Plazl, Igor

    2012-01-15

    The use of microchannel reactor based technologies within the scope of bioprocesses as process intensification and production platforms is gaining momentum. Such trend can be ascribed a particular set of characteristics of microchannel reactors, namely the enhanced mass and heat transfer, combined with easier handling and smaller volumes required, as compared to traditional reactors. In the present work, a continuous production process of 4-cholesten-3-one by the enzymatic oxidation of cholesterol without the formation of any by-product was assessed. The production was carried out within Y-shaped microchannel reactors in an aqueous-organic two-phase system. Substrate was delivered from the organic phase to aqueous phase containing cholesterol oxidase and the product formed partitions back to the organic phase. The aqueous phase was then forced through a plug-flow reactor, containing immobilized catalase. This step aimed at the reduction of hydrogen peroxide formed as a by-product during cholesterol oxidation, to avoid cholesterol oxidase deactivation due to said by-product. This setup was compared with traditional reactors and modes of operation. The results showed that microchannel reactor geometry outperformed traditional stirred tank and plug-flow reactors reaching similar conversion yields at reduced residence time. Coupling the plug-flow reactor containing catalase enabled aqueous phase reuse with maintenance of 30% catalytic activity of cholesterol oxidase while eliminating hydrogen peroxide. A final production of 36 m of cholestenone was reached after 300 hours of operation.

  4. Microfabrication of Microchannels for Fuel Cell Plates

    Directory of Open Access Journals (Sweden)

    Ho Su Jang

    2009-12-01

    Full Text Available Portable electronic devices such as notebook computers, PDAs, cellular phones, etc., are being widely used, and they increasingly need cheap, efficient, and lightweight power sources. Fuel cells have been proposed as possible power sources to address issues that involve energy production and the environment. In particular, a small type of fuel-cell system is known to be suitable for portable electronic devices. The development of micro fuel cell systems can be achieved by the application of microchannel technology. In this study, the conventional method of chemical etching and the mechanical machining method of micro end milling were used for the microfabrication of microchannel for fuel cell separators. The two methods were compared in terms of their performance in the fabrication with regards to dimensional errors, flatness, straightness, and surface roughness. Following microchannel fabrication, the powder blasting technique is introduced to improve the coating performance of the catalyst on the surface of the microchannel. Experimental results show that end milling can remarkably increase the fabrication performance and that surface treatment by powder blasting can improve the performance of catalyst coating.

  5. Proton Conduction in Sulfonated Organic-Inorganic Hybrid Monoliths with Hierarchical Pore Structure.

    Science.gov (United States)

    von der Lehr, Martin; Seidler, Christopher F; Taffa, Dereje H; Wark, Michael; Smarsly, Bernd M; Marschall, Roland

    2016-09-28

    Porous organic-inorganic hybrid monoliths with hierarchical porosity exhibiting macro- and mesopores are prepared via sol-gel process under variation of the mesopore size. Organic moieties in the pore walls are incorporated by substituting up to 10% of the silicon precursor tetramethylorthosilicate with bisilylated benzene molecules. After functionalization with sulfonic acid groups, the resulting sulfonated hybrid monoliths featuring a bimodal pore structure are investigated regarding proton conduction depending on temperature and relative humidity. The hierarchical pore system and controlled mesopore design turn out to be crucial for sulfonation and proton conduction. These sulfonated hybrid hierarchical monoliths containing only 10% organic precursor exhibit higher proton conduction at different relative humidities than sulfonated periodic mesoporous organosilica made of 100% bisilylated precursors exhibiting solely mesopores, even with a lower concentration of sulfonic acid groups.

  6. Light Weight Silicon Mirrors for Space Instrumentation

    Science.gov (United States)

    Bly, Vincent T.; Hill, Peter C.; Hagopian, John G.; Strojay, Carl R.; Miller, Timothy

    2012-01-01

    Each mirror is a monolithic structure from a single crystal of silicon. The mirrors are light weighted after the optical surface is ground and polished. Mirrors made during the initial phase of this work were typically 1/50 lambda or better (RMS at 633 n m)

  7. Multimodal Electrothermal Silicon Microgrippers for Nanotube Manipulation

    DEFF Research Database (Denmark)

    Nordström Andersen, Karin; Petersen, Dirch Hjorth; Carlson, Kenneth

    2009-01-01

    Microgrippers that are able to manipulate nanoobjects reproducibly are key components in 3-D nanomanipulation systems. We present here a monolithic electrothermal microgripper prepared by silicon microfabrication, and demonstrate pick-and-place of an as-grown carbon nanotube from a 2-D array onto...

  8. Monolithic Fuel Fabrication Process Development

    Energy Technology Data Exchange (ETDEWEB)

    C. R. Clark; N. P. Hallinan; J. F. Jue; D. D. Keiser; J. M. Wight

    2006-05-01

    The pursuit of a high uranium density research reactor fuel plate has led to monolithic fuel, which possesses the greatest possible uranium density in the fuel region. Process developments in fabrication development include friction stir welding tool geometry and cooling improvements and a reduction in the length of time required to complete the transient liquid phase bonding process. Annealing effects on the microstructures of the U-10Mo foil and friction stir welded aluminum 6061 cladding are also examined.

  9. Pressure drop in CIM disk monolithic columns.

    Science.gov (United States)

    Mihelic, Igor; Nemec, Damjan; Podgornik, Ales; Koloini, Tine

    2005-02-11

    Pressure drop analysis in commercial CIM disk monolithic columns is presented. Experimental measurements of pressure drop are compared to hydrodynamic models usually employed for prediction of pressure drop in packed beds, e.g. free surface model and capillary model applying hydraulic radius concept. However, the comparison between pressure drop in monolith and adequate packed bed give unexpected results. Pressure drop in a CIM disk monolithic column is approximately 50% lower than in an adequate packed bed of spheres having the same hydraulic radius as CIM disk monolith; meaning they both have the same porosity and the same specific surface area. This phenomenon seems to be a consequence of the monolithic porous structure which is quite different in terms of the pore size distribution and parallel pore nonuniformity compared to the one in conventional packed beds. The number of self-similar levels for the CIM monoliths was estimated to be between 1.03 and 2.75.

  10. Stacked Metal Silicide/Silicon Far-Infrared Detectors

    Science.gov (United States)

    Maserjian, Joseph

    1988-01-01

    Selective doping of silicon in proposed metal silicide/silicon Schottky-barrier infrared photodetector increases maximum detectable wavelength. Stacking layers to form multiple Schottky barriers increases quantum efficiency of detector. Detectors of new type enhance capabilities of far-infrared imaging arrays. Grows by molecular-beam epitaxy on silicon waferscontaining very-large-scale integrated circuits. Imaging arrays of detectors made in monolithic units with image-preprocessing circuitry.

  11. Graphene-supported metal oxide monolith

    Energy Technology Data Exchange (ETDEWEB)

    Worsley, Marcus A.; Baumann, Theodore F.; Biener, Juergen; Biener, Monika A.; Wang, Yinmin; Ye, Jianchao; Tylski, Elijah

    2017-01-10

    A composition comprising at least one graphene-supported metal oxide monolith, said monolith comprising a three-dimensional structure of graphene sheets crosslinked by covalent carbon bonds, wherein the graphene sheets are coated by at least one metal oxide such as iron oxide or titanium oxide. Also provided is an electrode comprising the aforementioned graphene-supported metal oxide monolith, wherein the electrode can be substantially free of any carbon-black and substantially free of any binder.

  12. Graphene-supported metal oxide monolith

    Science.gov (United States)

    Worsley, Marcus A.; Baumann, Theodore F.; Biener, Juergen; Biener, Monika A.; Wang, Yinmin; Ye, Jianchao; Tylski, Elijah

    2017-01-10

    A composition comprising at least one graphene-supported metal oxide monolith, said monolith comprising a three-dimensional structure of graphene sheets crosslinked by covalent carbon bonds, wherein the graphene sheets are coated by at least one metal oxide such as iron oxide or titanium oxide. Also provided is an electrode comprising the aforementioned graphene-supported metal oxide monolith, wherein the electrode can be substantially free of any carbon-black and substantially free of any binder.

  13. Process for separating nitrogen from methane using microchannel process technology

    Science.gov (United States)

    Tonkovich, Anna Lee; Qiu, Dongming; Dritz, Terence Andrew; Neagle, Paul; Litt, Robert Dwayne; Arora, Ravi; Lamont, Michael Jay; Pagnotto, Kristina M.

    2007-07-31

    The disclosed invention relates to a process for separating methane or nitrogen from a fluid mixture comprising methane and nitrogen, the process comprising: (A) flowing the fluid mixture into a microchannel separator, the microchannel separator comprising a plurality of process microchannels containing a sorption medium, the fluid mixture being maintained in the microchannel separator until at least part of the methane or nitrogen is sorbed by the sorption medium, and removing non-sorbed parts of the fluid mixture from the microchannel separator; and (B) desorbing the methane or nitrogen from the sorption medium and removing the desorbed methane or nitrogen from the microchannel separator. The process is suitable for upgrading methane from coal mines, landfills, and other sub-quality sources.

  14. Inkjet injection of DNA droplets for microchannel array electrophoresis.

    Science.gov (United States)

    Yasui, Takao; Inoue, Yosuke; Naito, Toyohiro; Okamoto, Yukihiro; Kaji, Noritada; Tokeshi, Manabu; Baba, Yoshinobu

    2012-11-06

    We demonstrated DNA droplets could be injected with an inkjet injector for microchannel array electrophoresis and attained high throughput analysis of biomolecules. This injection method greatly reduced both analysis time and sample amount, compared with a conventional microchip electrophoresis method, and allowed high parallelization of a microchannel array on a small substrate. Since we do not need to use complicated electric programs or microchannel design, our injection method should facilitate omics analyses and contribute to high performance clinical assays.

  15. Method of producing microchannel and nanochannel articles

    Science.gov (United States)

    D'Urso, Brian R.

    2010-05-04

    A method of making an article having channels therethrough includes the steps of: providing a ductile structure defining at least one macro-channel, the macro-channel containing a salt; drawing the ductile structure in the axial direction of the at least one macro-channel to reduce diameter of the macro-channel; and contacting the salt with a solvent to dissolve the salt to produce an article having at least one microchannel.

  16. The Effects of Engineering Design on Heterogeneous Biocatalysis in Microchannels

    Science.gov (United States)

    Jones, Frank; Bailey, Robert; Wilson, Stephanie; Hiestand, James

    The results of a numerical study of the fundamental interactions of engineering design and micromixing on conversion in packed microchannels are presented. Previously, channel-based microreactors made of molded silicon plastic were designed, fabricated, and experimentally tested. These reactors have enzymes immobilized on the channel walls by various methods including layerby-layer nano self-assembly techniques. They also contain molded packing features to add reactive surface area and to redistribute the fluid. An arbitrary but intuitively sensible packing arrangement was initially chosen and used in experimental studies. The current computer simulation study was undertaken to understand how static laminar mixing affects the conversion efficiency. The reactors previously used experimentally have been simulated using CFD-ACE+ multiphysics software (ESI CFD Inc., Huntsville, AL). It is found that packing significantly increases conversion when compared with empty channels over the entire flow rate range of the study (0.25

  17. Experimental microchannel heat sink performance studies using nano-fluids

    Energy Technology Data Exchange (ETDEWEB)

    Chein, Reiyu; Chuang, Jason [Department of Mechanical Engineering, National Chung Hsing University, 250 Kuo-Kuang Rd., Taichung City, Taiwan (China)

    2007-01-15

    In this study, microchannel heat sink (MCHS) performance using nano-fluids as coolants is addressed. We first carried out a simple theoretical analysis that indicated more energy and lower MCHS wall temperature could be obtained under the assumption that heat transfer could be enhanced by the presence of nano-particles. Experiments were then performed to verify the theoretical predictions. A silicon MCHS was made and CuO-H{sub 2}O mixtures without a dispersion agent were used as the coolants. The CuO particle volume fraction was in the range of 0.2 to 0.4%. It was found that nano-fluid-cooled MCHS could absorb more energy than water-cooled MCHS when the flow rate was low. For high flow rates, the heat transfer was dominated by the volume flow rate and nano-particles did not contribute to the extra heat absorption. The measured MCHS wall temperature variations agreed with the theoretical prediction for low flow rate. For high flow rate, the measured MCHS wall temperatures did not completely agree with the theoretical prediction due to the particle agglomeration and deposition. It was also found that raising the nano-fluid bulk temperature could prevent the particles from being agglomerated into larger scale particle clusters. The experimental result also indicated that only slightly increase in pressure drop due to the presence of nano-particles in MCHS operation. (author)

  18. Dynamic characterization of monolithic and composite ceramic materials using Hopkinson bar

    OpenAIRE

    2002-01-01

    5 pages, 11 figures. [EN] The mechanical behaviour of monolithic and composite ceramic materials was analysed under impact conditions, using the Hopkinson bar to study the response and failure modes. The materials considered were alumina (Al2O3) and silicon carbide platelet / alumina matrix (Al2O3/ SiCpl) composites. Because of the high hardness of ceramics, modifications of the conventional Hopkinson bar device were done to prevent the damage of the bars surface. Stress-strain curves obta...

  19. Water flow boiling behaviors in hydrophilic and hydrophobic microchannels

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Chiwoong; Yu, Dongin; Kim, Moohwan [Pohang University of Science and Technology (Korea, Republic of). Dept. of Mechanical Engineering

    2009-07-01

    The wettability is one of issues on two-phase flow in a microchannel. However, previous studies of wettability effect on two-phase flow have conducted only isothermal condition. Moreover, most studies have used conventional micro/mini-tubes due to difficulties of their fabrication. The objective of our study is to understand the wettability effect on flow boiling in a rectangular microchannel. In the first, new micro-electro-mechanical-system (MEMS) fabrication technique was developed to obtain a single glass rectangular microchannel and localized six micro heaters. A photosensitive glass was used as base material. The photosensitive glass is hydrophilic, so the hydrophobic microchannel was prepared by coating SAM, flow boiling experiments were conducted in hydrophilic and hydrophobic microchannels with micro heaters. The experiment range was the mass flux of 25 and 75 kg/m{sup 2}s, the heat flux of 30 - 430 k W/m2 and quality of 0 - 0.3. A working fluid was de-ionized and degassed water. The local heat transfer coefficient was evaluated at the local micro heater section. Also, flow regimes in the microchannel were visualized by using a high-speed camera with a long-distance microscope. Heat transfer was analyzed with visualization results. Heat transfer in the hydrophobic microchannel was enhanced by higher nucleation site density and delayed local dryout. The pressure drop in the hydrophobic microchannel was higher than that in the hydrophilic microchannel. (author)

  20. Heat transfer and fluid flow in minichannels and microchannels

    CERN Document Server

    Kandlikar, Satish; Li, Dongqing; Colin, Stephane; King, Michael R

    2013-01-01

    Heat exchangers with minichannel and microchannel flow passages are becoming increasingly popular due to their ability to remove large heat fluxes under single-phase and two-phase applications. Heat Transfer and Fluid Flow in Minichannels and Microchannels methodically covers gas, liquid, and electrokinetic flows, as well as flow boiling and condensation, in minichannel and microchannel applications. Examining biomedical applications as well, the book is an ideal reference for anyone involved in the design processes of microchannel flow passages in a heat exchanger. Each chapter is accompan

  1. Evaporative CO$_2$ microchannel cooling for the LHCb VELO pixel upgrade

    CERN Document Server

    de Aguiar Francisco, Oscar A; Collins, Paula; Dumps, Raphael; John, Malcolm; Mapelli, Alessandro; Romagnoli, Giulia

    2015-01-01

    The LHCb Vertex Detector (VELO) will be upgraded in 2018 to a lightweight pixel detector capable of 40 MHz readout and operation in very close proximity to the LHC beams. The thermal management of the system will be provided by evaporative CO$_2$ circulating in microchannels embedded within thin silicon plates. This solution has been selected due to the excellent thermal efficiency, the absence of thermal expansion mismatch with silicon ASICs and sensors, the radiation hardness of CO$_2$, and very low contribution to the material budget. Although microchannel cooling is gaining considerable attention for applications related to microelectronics, it is still a novel technology for particle physics experiments, in particular when combined with evaporative CO$_2$ cooling. The R&D effort for LHCb is focused on the design and layout of the channels together with a fluidic connector and its attachment which must withstand pressures up to 170 bar. Even distribution of the coolant is ensured by means of the use o...

  2. Evaporative CO2 microchannel cooling for the LHCb VELO pixel upgrade

    Science.gov (United States)

    de Aguiar Francisco, O. A.; Buytaert, J.; Collins, P.; Dumps, R.; John, M.; Mapelli, A.; Romagnoli, G.

    2015-05-01

    The LHCb Vertex Detector (VELO) will be upgraded in 2018 to a lightweight pixel detector capable of 40 MHz readout and operation in very close proximity to the LHC beams. The thermal management of the system will be provided by evaporative CO2 circulating in microchannels embedded within thin silicon plates. This solution has been selected due to the excellent thermal efficiency, the absence of thermal expansion mismatch with silicon ASICs and sensors, the radiation hardness of CO2, and very low contribution to the material budget. Although microchannel cooling is gaining considerable attention for applications related to microelectronics, it is still a novel technology for particle physics experiments, in particular when combined with evaporative CO2 cooling. The R&D effort for LHCb is focused on the design and layout of the channels together with a fluidic connector and its attachment which must withstand pressures up to 170 bar. Even distribution of the coolant is ensured by means of the use of restrictions implemented before the entrance to a race track like layout of the main cooling channels. The coolant flow and pressure drop have been simulated as well as the thermal performance of the device. This proceeding describes the design and optimization of the cooling system for LHCb and the latest prototyping results.

  3. Microfluidics in silicon/polymer technology as a cost-efficient alternative to silicon/glass

    Science.gov (United States)

    Kalkandjiev, K.; Riegger, L.; Kosse, D.; Welsche, M.; Gutzweiler, L.; Zengerle, R.; Koltay, P.

    2011-02-01

    We investigate TMMF photopolymer as a cost-efficient alternative to glass for the leak-tight sealing of high-density silicon microchannels. TMMF enables low temperature sealing and access to structures underneath via lamination and standard UV-lithography instead of costly glass machining and anodic bonding. TMMF is highly transparent and has a low autofluorescence for wavelengths larger than 400 nm. As the photopolymer is too thin for implementing bulky world-to-chip interfaces, we propose adhesive bonding of cyclic olefin copolymer (COC) modules. All materials were tested according ISO 10993-5 and showed no cytotoxic effects on the proliferation of L929 cells. To quantify the cost efficiency of the proposed techniques, we used an established silicon/Pyrex nanoliter dispenser as a reference and replaced structured Pyrex wafers by TMMF laminates and COC modules. Thus, consumable costs, manpower and machine time related to sealing of the microchannels and implementing the world-to-chip interface could be significantly reduced. Leak tightness was proved by applying a pressure of 0.2 MPa for 5 h without delamination or crosstalk between neighboring microchannels located only 100 µm apart. In contrast to anodic bonding, the proposed techniques are tolerant to surface inhomogeneities. They enable manufacturing of silicon/polymer microfluidics at lower costs and without compromising the performance compared to corresponding silicon/glass devices.

  4. A Monolithic active pixel sensor for ionizing radiation using a 180nm HV-SOI process

    OpenAIRE

    Hemperek, Tomasz; Kishishita, Tetsuichi; Krüger, Hans; Wermes, Norbert

    2014-01-01

    An improved SOI-MAPS (Silicon On Insulator Monolithic Active Pixel Sensor) for ionizing radiation based on thick-film High Voltage SOI technology (HV-SOI) has been developed. Similar to existing Fully Depleted SOI-based (FD-SOI) MAPS, a buried silicon oxide inter-dielectric (BOX) layer is used to separate the CMOS electronics from the handle wafer which is used as a depleted charge collection layer. FD-SOI MAPS suffer from radiation damage such as transistor threshold voltage shifts due to ch...

  5. Highly efficient coupling between a monolithically integrated photonic crystal cavity and a bus waveguide

    Science.gov (United States)

    Debnath, Kapil; Welna, Karl; Ferrera, Marcello; Deasy, Kieran; Lidzey, David; Krauss, Thomas F.; O'Faolain, Liam

    2012-01-01

    We experimentally demonstrate a new optical filter design comprising of a photonic crystal cavity and a low index bus waveguide which are monolithically integrated on a silicon-on-insulator (SOI) platform. We have fabricated oxide clad PhC cavities with a silicon nitride waveguide positioned directly above, such that there is an overlap between the evanescent tails of the two modes. We have realised an extinction ratio of 7.5dB for cavities with total Q of 50,000.

  6. Monolithically integrated absolute frequency comb laser system

    Energy Technology Data Exchange (ETDEWEB)

    Wanke, Michael C.

    2016-07-12

    Rather than down-convert optical frequencies, a QCL laser system directly generates a THz frequency comb in a compact monolithically integrated chip that can be locked to an absolute frequency without the need of a frequency-comb synthesizer. The monolithic, absolute frequency comb can provide a THz frequency reference and tool for high-resolution broad band spectroscopy.

  7. Nanosecond monolithic CMOS readout cell

    Science.gov (United States)

    Souchkov, Vitali V.

    2004-08-24

    A pulse shaper is implemented in monolithic CMOS with a delay unit formed of a unity gain buffer. The shaper is formed of a difference amplifier having one input connected directly to an input signal and a second input connected to a delayed input signal through the buffer. An elementary cell is based on the pulse shaper and a timing circuit which gates the output of an integrator connected to the pulse shaper output. A detector readout system is formed of a plurality of elementary cells, each connected to a pixel of a pixel array, or to a microstrip of a plurality of microstrips, or to a detector segment.

  8. Compact monolithic capacitive discharge unit

    Science.gov (United States)

    Roesler, Alexander W.; Vernon, George E.; Hoke, Darren A.; De Marquis, Virginia K.; Harris, Steven M.

    2007-06-26

    A compact monolithic capacitive discharge unit (CDU) is disclosed in which a thyristor switch and a flyback charging circuit are both sandwiched about a ceramic energy storage capacitor. The result is a compact rugged assembly which provides a low-inductance current discharge path. The flyback charging circuit preferably includes a low-temperature co-fired ceramic transformer. The CDU can further include one or more ceramic substrates for enclosing the thyristor switch and for holding various passive components used in the flyback charging circuit. A load such as a detonator can also be attached directly to the CDU.

  9. Magneto-Optical Thin Films for On-Chip Monolithic Integration of Non-Reciprocal Photonic Devices

    Directory of Open Access Journals (Sweden)

    Mehmet Cengiz Onbasli

    2013-11-01

    Full Text Available Achieving monolithic integration of nonreciprocal photonic devices on semiconductor substrates has been long sought by the photonics research society. One way to achieve this goal is to deposit high quality magneto-optical oxide thin films on a semiconductor substrate. In this paper, we review our recent research activity on magneto-optical oxide thin films toward the goal of monolithic integration of nonreciprocal photonic devices on silicon. We demonstrate high Faraday rotation at telecommunication wavelengths in several novel magnetooptical oxide thin films including Co substituted CeO2−δ, Co- or Fe-substituted SrTiO3−δ, as well as polycrystalline garnets on silicon. Figures of merit of 3~4 deg/dB and 21 deg/dB are achieved in epitaxial Sr(Ti0.2Ga0.4Fe0.4O3−δ and polycrystalline (CeY2Fe5O12 films, respectively. We also demonstrate an optical isolator on silicon, based on a racetrack resonator using polycrystalline (CeY2Fe5O12/silicon strip-loaded waveguides. Our work demonstrates that physical vapor deposited magneto-optical oxide thin films on silicon can achieve high Faraday rotation, low optical loss and high magneto-optical figure of merit, therefore enabling novel high-performance non-reciprocal photonic devices monolithically integrated on semiconductor substrates.

  10. Influence of micro-channel shape and magnetic material on the magneto-refrigeration process of integrated circuits.

    Science.gov (United States)

    Pereira, A M; Soares, J C; Ventura, J; Sousa, J B; Araujo, J P; Oliveira, J C R E

    2010-04-01

    We developed a two dimensional transient numerical model that solves the first step of heat transfer of an active magnetic regenerative refrigerator (AMR) using the heat conduction equation for an adiabatic system. For micro-refrigeration, an AMR device is constituted by a magnetic material, placed on a silicon wafer containing micro-channels where a heat exchanging fluid flows. The magnetic materials used in the simulations are the promising the Gd5Si2Ge2, La(Fe0.88Si0.22)13 and La0.66Sr0.33MnO3 compounds, because they exhibit a giant magnetocaloric effect near room temperature. We considered different initial conditions, namely different micro-channel shapes, sizes and separations, aiming to increase the performance of the micro-cooler device. The influence of the thickness of the magnetic material on refrigeration power is also studied.

  11. Reprocessing of LEU U-Mo Dispersion and Monolithic Fuels

    Energy Technology Data Exchange (ETDEWEB)

    Vandegrift, G.F.; Jerden, J.; Stepinski, D.C.; Figueroa, J.; Williamson, M.A.; Kleeck, M.A. Van; Blaskovitz, R.J.; Ziegler, A.J.; Maggos, L.E.; Swanson, J.; Fortner, J.; Bakel, A.J. [Chemical Sciences and Engineering Division, Argonne National Laboratory, 9700 S. Cass Ave., Argonne, IL 60439 (United States)

    2011-07-01

    For conversion of high-performance research reactors from high-enriched uranium (HEU) to low-enriched uranium (LEU) fuel, a fuel material with a higher density than uranium aluminide is required. Development studies are underway to develop U-Mo dispersion and monolithic fuels for conversion of several high- performance reactors. For dispersion fuels, development is narrowing down to a composition of U-7Mo dispersed in an aluminium matrix containing {approx}5% silicon. For monolithic fuels to be used in high performance research reactors in the United States, a zirconium-bonded U-10Mo foil appears to be the fuel of choice. For conversion to be realized a back-end disposition path is required for both fuels; one disposition pathway is reprocessing. Argonne National Laboratory is developing a pyroprocess for reprocessing spent monolithic fuel. Pyroprocessing was chosen over conventional aqueous solvent extraction due to the necessity of adding fluoride to the fuel-dissolution solution in order to dissolve the zirconium bonding layer on the U-Mo fuel. The proposed flowsheet and development activities will be described. A literature survey points to the ability to reprocess U-Mo dispersion fuels by an aqueous process, but due to several special characteristics of the fuel, the solvent-extraction flowsheets will be a departure from that normally used for the reprocessing of power reactor fuel. Special concerns that must be addressed in reprocessing these fuels are, for example, the low solubilities of uranyl molybdate, molybdic acid, and silicic acid in nitric acid solutions. This paper will address these concerns and development activities required to overcome them. (author)

  12. Microchannel arrays with improved accessibility and use for cell studies and emulsification

    Science.gov (United States)

    Kikuchi, Yuji; Kikuchi, Hiroko E.; Kuboki, Yoshinori; Nakajima, Mitsutoshi

    2000-03-01

    Arrays of microgrooves (groove width; 2, 3, 4, 5, 6, 7, 8, 10, 12, and 14 micrometer, groove interval; width x3, x10, and x20, one size and interval per chip) each connecting a center well and a side edge of a silicon substrate were created by photolithography and anisotropic wet etching. A penetrating hole was made by sand blast at the substrate center for the access to the center well. By tightly covering the substrate surface with a glass plate, the microgroove arrays were converted to microchannel arrays having one ends open at the side edges of the substrate. These microchannel arrays were used for cell trapping for microinjection and also used for emulsification. Poplar (Populus alba) protoplasts were used for the test of cell trapping. Cells showed a very large variation in size and irregularity in shape, and, furthermore, the protoplast preparation contained a number of cell membrane fragments and chloroplasts. Despite the cell size and shape variations and obstruction by the admixtures, many cells could be trapped by aspiration at the channel ends because of their openness to the outside free space and also their large multiplicity in parallel. The free space outside the side of the substrate allowed a free manipulation of a glass micropipette under microscopic observation using transmitted illumination. The microscopic observation direction nearly perpendicular to the movement directions of the micropipette further allowed the movement of the pipette tip nearly always in focus. These led to an easy pointing and puncturing. In addition, the cell trapping points in a line made successive approach to adjacent cells easier. Soybean oil containing 1.5 wt% polyoxyethylene(20)sorbitan monoolete as a surfactant was forced to flow into physiological saline filling the outside of the substrate through the microchannels. Regularly sized oil particles were created by this process with a variation coefficient (S.D./mean) 16% of their diameter. This variation, which is

  13. Critical heat flux in flow boiling in microchannels

    CERN Document Server

    Saha, Sujoy Kumar

    2015-01-01

    This Brief concerns the important problem of critical heat flux in flow boiling in microchannels. A companion edition in the SpringerBrief Subseries on Thermal Engineering and Applied Science to “Heat Transfer and Pressure Drop in Flow Boiling in Microchannels,” by the same author team, this volume is idea for professionals, researchers, and graduate students concerned with electronic cooling.

  14. A Geometric Model for the Dynamics of Microchannel Emulsification

    NARCIS (Netherlands)

    Zwan, van der E.A.; Schroën, C.G.P.H.; Boom, R.M.

    2009-01-01

    Microchannel emulsification is an interfacial tension driven method to produce monodisperse microdroplets, or microspheres. In this paper we introduce a model for describing the dynamics of microchannel emulsification based on simple time dependent geometric shape analysis. The model is based on mec

  15. Monolithic translucent BaMgAl10O17:Eu2+ phosphors for laser-driven solid state lighting

    Directory of Open Access Journals (Sweden)

    Clayton Cozzan

    2016-10-01

    Full Text Available With high power light emitting diodes and laser diodes being explored for white light generation and visible light communication, thermally robust encapsulation schemes for color-converting inorganic phosphors are essential. In the current work, the canonical blue-emitting phosphor, high purity Eu-doped BaMgAl10O17, has been prepared using microwave-assisted heating (25 min and densified into translucent ceramic phosphor monoliths using spark plasma sintering (30 min. The resulting translucent ceramic monoliths convert UV laser light to blue light with the same efficiency as the starting powder and provide superior thermal management in comparison with silicone encapsulation.

  16. Monolithic translucent BaMgAl10O17:Eu2+ phosphors for laser-driven solid state lighting

    Science.gov (United States)

    Cozzan, Clayton; Brady, Michael J.; O'Dea, Nicholas; Levin, Emily E.; Nakamura, Shuji; DenBaars, Steven P.; Seshadri, Ram

    2016-10-01

    With high power light emitting diodes and laser diodes being explored for white light generation and visible light communication, thermally robust encapsulation schemes for color-converting inorganic phosphors are essential. In the current work, the canonical blue-emitting phosphor, high purity Eu-doped BaMgAl10O17, has been prepared using microwave-assisted heating (25 min) and densified into translucent ceramic phosphor monoliths using spark plasma sintering (30 min). The resulting translucent ceramic monoliths convert UV laser light to blue light with the same efficiency as the starting powder and provide superior thermal management in comparison with silicone encapsulation.

  17. Fabrication of Monolithic RERTR Fuels by Hot Isostatic Pressing

    Energy Technology Data Exchange (ETDEWEB)

    Jan-Fong Jue; Blair H. Park; Curtis R. Clark; Glenn A. Moore; Dennis D. Keiser, Jr.

    2010-11-01

    The RERTR (Reduced Enrichment for Research and Test Reactors) Program is developing advanced nuclear fuels for high-power test reactors. Monolithic fuel design provides higher uranium loading than that of the traditional dispersion fuel design. Hot isostatic pressing is a promising process for low-cost batch fabrication of monolithic RERTR fuel plates for these high-power reactors. Bonding U Mo fuel foil and 6061 Al cladding by hot isostatic press bonding was successfully developed at Idaho National Laboratory. Due to the relatively high processing temperature, the interaction between fuel meat and aluminum cladding is a concern. Two different methods were employed to mitigate this effect: (1) a diffusion barrier and (2) a doping addition to the interface. Both types of fuel plates have been fabricated by hot isostatic press bonding. Preliminary results show that the direct fuel/cladding interaction during the bonding process was eliminated by introducing a thin zirconium diffusion barrier layer between the fuel and the cladding. Fuel plates were also produced and characterized with a silicon-rich interlayer between fuel and cladding. This paper reports the recent progress of this developmental effort and identifies the areas that need further attention.

  18. Microfluidic devices and methods including porous polymer monoliths

    Science.gov (United States)

    Hatch, Anson V; Sommer, Gregory J; Singh, Anup K; Wang, Ying-Chih; Abhyankar, Vinay V

    2014-04-22

    Microfluidic devices and methods including porous polymer monoliths are described. Polymerization techniques may be used to generate porous polymer monoliths having pores defined by a liquid component of a fluid mixture. The fluid mixture may contain iniferters and the resulting porous polymer monolith may include surfaces terminated with iniferter species. Capture molecules may then be grafted to the monolith pores.

  19. Strained silicon as a new electro-optic material

    DEFF Research Database (Denmark)

    Jacobsen, Rune Shim; Andersen, Karin Nordström; Borel, Peter Ingo

    2006-01-01

    of a silicon waveguide, and the induced nonlinear coefficient, (2) 15 pm V-1, makes it possible to realize a silicon electro-optic modulator. The strain-induced linear electro-optic effect may be used to remove a bottleneck5 in modern computers by replacing the electronic bus with a much faster optical...... processing and transmission could potentially be performed by all-silicon electronic and optical components. Here we have discovered that a significant linear electro-optic effect is induced in silicon by breaking the crystal symmetry. The symmetry is broken by depositing a straining layer on top...... functionalities can be integrated into monolithic components based on the versatile silicon platform, is due to the limited active optical properties of silicon3. Recently, however, a continuous-wave Raman silicon laser was demonstrated4; if an effective modulator could also be realized in silicon, data...

  20. GaN Monolithic Power Amplifiers for Microwave Backhaul Applications

    Directory of Open Access Journals (Sweden)

    Roberto Quaglia

    2016-06-01

    Full Text Available Gallium nitride integrated technology is very promising not only for wireless applications at mobile frequencies (below 6 GHz but also for network backhaul radiolink deployment, now under deep revision for the incoming 5G generation of mobile communications. This contribution presents three linear power amplifiers realized on 0.25 μ m Gallium Nitride on Silicon Carbide monolithic integrated circuits for microwave backhaul applications: two combined power amplifiers working in the backhaul band around 7 GHz, and a more challenging third one working in the higher 15 GHz band. Architectures and main design steps are described, highlighting the pros and cons of Gallium Nitride with respect to the reference technology which, for these applications, is represented by gallium arsenide.

  1. Pool boiling visualization on open microchannel surfaces

    Directory of Open Access Journals (Sweden)

    Kaniowski Robert

    2017-01-01

    Full Text Available The paper presents visualization investigations into pool boiling heat transfer for open minichannel surfaces. The experiments were carried out wih saturated water at atmospheric pressure. Parallel microchannels fabricated by machining were about 0.3 mm wide and 0.2 to 0.4 mm deep. High-speed videos were used as an aid to understanding the heat transfer mechanism. The visualization study aimed at identifying nucleation sites of the departing bubbles and determining their diameters and frequency at various superheats.

  2. Force criterion of different electrolytes in microchannel

    Institute of Scientific and Technical Information of China (English)

    Ren Yu-Kun; Yan Hui; Jiang Hong-Yuan; Gu Jian-Zhong; Antonio Ramos

    2009-01-01

    The control and handling of fluids is central to many applications of the lab-on-chip. This paper analyzes the basic theory of manipulating different electrolytes and finds the two-dimensional model. Coulomb force and dielectric force belonging to the body force of different electrolytes in the microchannel were analyzed. The force criterion at the interface was concluded, and testified by the specific example. Three basic equations were analyzed and applied to simulate the phenomenon. The force criterion was proved to be correct based on the simulation results.

  3. Making bulk-conductive glass microchannel plates

    Science.gov (United States)

    Yi, Jay J. L.; Niu, Lihong

    2008-02-01

    The fabrication of microchannel plate (MCP) with bulk-conductive characteristics has been studied. Semiconducting clad glass and leachable core glass were used for drawing fibers and making MCP. Co-axial single fiber was drawn from a platinum double-crucible in an automatic fiberizing system, and the fibers were stacked and redrawn into multifiber by a special gripping mechanism. The multifibers were stacked again and the boule was made and sliced into discs. New MCPs were made after chemically leaching process without the traditional hydrogen firing. It was shown that bulk-conductive glass MCP can operate at higher voltage with lower noise.

  4. Modelling refrigerant distribution in microchannel evaporators

    DEFF Research Database (Denmark)

    Brix, Wiebke; Kærn, Martin Ryhl; Elmegaard, Brian

    2009-01-01

    The effects of refrigerant maldistribution in parallel evaporator channels on the heat exchanger performance are investigated numerically. For this purpose a 1D steady state model of refrigerant R134a evaporating in a microchannel tube is built and validated against other evaporator models. A study...... of the refrigerant distribution is carried out for two channels in parallel and for two different cases. In the first case maldistribution of the inlet quality into the channels is considered, and in the second case a non-uniform airflow on the secondary side is considered. In both cases the total mixed superheat...

  5. Development of Hybrid and Monolithic Silicon Micropattern Detectors

    CERN Multimedia

    Beker, H; Snoeys, W; Campbell, M; Lemeilleur, F; Ropotar, I

    2002-01-01

    %RD-19 \\\\ \\\\ In a collaborative effort between particle physics institutes and microelectronics industry we are undertaking the development of true 2-dimensional semiconductor particle detectors with on-chip signal processing and information extraction: the so-called micropattern detector. This detector is able to cope in a robust way with high multiplicity events at high rates, while allowing for a longer detector lifetime under irradiation and a thinner sensitive depletion region. Therefore, it will be ideally suited for the complicated events in the LHC p-p collider experiments. Following a $^{\\prime}$stepping stone$^{\\prime}$ approach several telescopes of pixel planes, totalling now 600 cm$^{2}$ with \\(>\\)~1~M elements have been used in the WA97, NA50 and NA57 lead ion experiments. This new technology has facilitated the tracking considerably (see Fig.1). Not only Si but also GaAs and possibly diamond matrices can be connected to the readout matrix. Tests with GaAs pixel detectors with the RD-19 readout ...

  6. Monolithic Continuous-Flow Bioreactors

    Science.gov (United States)

    Stephanopoulos, Gregory; Kornfield, Julia A.; Voecks, Gerald A.

    1993-01-01

    Monolithic ceramic matrices containing many small flow passages useful as continuous-flow bioreactors. Ceramic matrix containing passages made by extruding and firing suitable ceramic. Pores in matrix provide attachment medium for film of cells and allow free movement of solution. Material one not toxic to micro-organisms grown in reactor. In reactor, liquid nutrients flow over, and liquid reaction products flow from, cell culture immobilized in one set of channels while oxygen flows to, and gaseous reaction products flow from, culture in adjacent set of passages. Cells live on inner surfaces containing flowing nutrient and in pores of walls of passages. Ready access to nutrients and oxygen in channels. They generate continuous high yield characteristic of immobilized cells, without large expenditure of energy otherwise incurred if necessary to pump nutrient solution through dense biomass as in bioreactors of other types.

  7. Anisotropically structured magnetic aerogel monoliths

    Science.gov (United States)

    Heiligtag, Florian J.; Airaghi Leccardi, Marta J. I.; Erdem, Derya; Süess, Martin J.; Niederberger, Markus

    2014-10-01

    Texturing of magnetic ceramics and composites by aligning and fixing of colloidal particles in a magnetic field is a powerful strategy to induce anisotropic chemical, physical and especially mechanical properties into bulk materials. If porosity could be introduced, anisotropically structured magnetic materials would be the perfect supports for magnetic separations in biotechnology or for magnetic field-assisted chemical reactions. Aerogels, combining high porosity with nanoscale structural features, offer an exceptionally large surface area, but they are difficult to magnetically texture. Here we present the preparation of anatase-magnetite aerogel monoliths via the assembly of preformed nanocrystallites. Different approaches are proposed to produce macroscopic bodies with gradient-like magnetic segmentation or with strongly anisotropic magnetic texture.Texturing of magnetic ceramics and composites by aligning and fixing of colloidal particles in a magnetic field is a powerful strategy to induce anisotropic chemical, physical and especially mechanical properties into bulk materials. If porosity could be introduced, anisotropically structured magnetic materials would be the perfect supports for magnetic separations in biotechnology or for magnetic field-assisted chemical reactions. Aerogels, combining high porosity with nanoscale structural features, offer an exceptionally large surface area, but they are difficult to magnetically texture. Here we present the preparation of anatase-magnetite aerogel monoliths via the assembly of preformed nanocrystallites. Different approaches are proposed to produce macroscopic bodies with gradient-like magnetic segmentation or with strongly anisotropic magnetic texture. Electronic supplementary information (ESI) available: Digital photographs of dispersions and gels with different water-to-ethanol ratios; magnetic measurements of an anatase aerogel containing 0.25 mol% Fe3O4 nanoparticles; XRD patterns of the iron oxide and

  8. Microchannel Reactor System for Catalytic Hydrogenation

    Energy Technology Data Exchange (ETDEWEB)

    Adeniyi Lawal; Woo Lee; Ron Besser; Donald Kientzler; Luke Achenie

    2010-12-22

    We successfully demonstrated a novel process intensification concept enabled by the development of microchannel reactors, for energy efficient catalytic hydrogenation reactions at moderate temperature, and pressure, and low solvent levels. We designed, fabricated, evaluated, and optimized a laboratory-scale microchannel reactor system for hydrogenation of onitroanisole and a proprietary BMS molecule. In the second phase of the program, as a prelude to full-scale commercialization, we designed and developed a fully-automated skid-mounted multichannel microreactor pilot plant system for multiphase reactions. The system is capable of processing 1 – 10 kg/h of liquid substrate, and an industrially relevant immiscible liquid-liquid was successfully demonstrated on the system. Our microreactor-based pilot plant is one-of-akind. We anticipate that this process intensification concept, if successfully demonstrated, will provide a paradigm-changing basis for replacing existing energy inefficient, cost ineffective, environmentally detrimental slurry semi-batch reactor-based manufacturing practiced in the pharmaceutical and fine chemicals industries.

  9. Plugging of microchannels by spherical particles

    Science.gov (United States)

    Climent, Eric; Agbangla, Constant; Bacchin, Patrice

    2010-11-01

    We investigate by means of numerical simulations the dynamic formation of 3D structures of microparticle aggregates blocking the flow through microchannels. Both the geometries of a straight channel and a sudden reduction of section are analyzed. We use the Force Coupling Method (Climent & Maxey, 2010) to handle simultaneously multi-body hydrodynamic interactions of a confined flowing suspension together with particle/particle and particle/wall surface interactions leading to the adhesion and aggregation of particles. The basic idea of the Force Coupling Method relies on multipole expansion of velocity perturbations induced by the presence of particles in the flow. Simulation results show that varying the magnitude of DLVO interparticle and particle/wall interactions leads to distinct scenarios of pores clogging. We investigate the kinetics of the microchannel occlusion (corresponding to a temporal decrease of the bulk permeability of the channel). We identify the nature of the fouling mechanism: deposition, interception, bridging (see the papers of Sharp & Adrian (2005), Ramachandran & Fogler (1999) and Marshal, 2007).

  10. Experimental evaluations of the microchannel flow model.

    Science.gov (United States)

    Parker, K J

    2015-06-07

    Recent advances have enabled a new wave of biomechanics measurements, and have renewed interest in selecting appropriate rheological models for soft tissues such as the liver, thyroid, and prostate. The microchannel flow model was recently introduced to describe the linear response of tissue to stimuli such as stress relaxation or shear wave propagation. This model postulates a power law relaxation spectrum that results from a branching distribution of vessels and channels in normal soft tissue such as liver. In this work, the derivation is extended to determine the explicit link between the distribution of vessels and the relaxation spectrum. In addition, liver tissue is modified by temperature or salinity, and the resulting changes in tissue responses (by factors of 1.5 or greater) are reasonably predicted from the microchannel flow model, simply by considering the changes in fluid flow through the modified samples. The 2 and 4 parameter versions of the model are considered, and it is shown that in some cases the maximum time constant (corresponding to the minimum vessel diameters), could be altered in a way that has major impact on the observed tissue response. This could explain why an inflamed region is palpated as a harder bump compared to surrounding normal tissue.

  11. Surface cell immobilization within perfluoroalkoxy microchannels

    Science.gov (United States)

    Stojkovič, Gorazd; Krivec, Matic; Vesel, Alenka; Marinšek, Marjan; Žnidaršič-Plazl, Polona

    2014-11-01

    Perfluoroalkoxy (PFA) is one of the most promising materials for the fabrication of cheap, solvent resistant and reusable microfluidic chips, which have been recently recognized as effective tools for biocatalytic process development. The application of biocatalysts significantly depends on efficient immobilization of enzymes or cells within the reactor enabling long-term biocatalyst use. Functionalization of PFA microchannels by 3-aminopropyltriethoxysilane (ATPES) and glutaraldehyde was used for rapid preparation of microbioreactors with surface-immobilized cells. X-ray photoelectron spectroscopy and scanning electron microscopy were used to accurately monitor individual treatment steps and to select conditions for cell immobilization. The optimized protocol for Saccharomyces cerevisiae immobilization on PFA microchannel walls comprised ethanol surface pretreatment, 4 h contacting with 10% APTES aqueous solution, 10 min treatment with 1% glutaraldehyde and 20 min contacting with cells in deionized water. The same protocol enabled also immobilization of Escherichia coli, Pseudomonas putida and Bacillus subtilis cells on PFA surface in high densities. Furthermore, the developed procedure has been proved to be very efficient also for surface immobilization of tested cells on other materials that are used for microreactor fabrication, including glass, polystyrene, poly (methyl methacrylate), polycarbonate, and two olefin-based polymers, namely Zeonor® and Topas®.

  12. Microchannel Heat Exchangers with Carbon Dioxide

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, Y.; Ohadi, M.M.; Radermacher, R.

    2001-09-15

    The objective of the present study was to determine the performance of CO{sub 2} microchannel evaporators and gas coolers in operational conditions representing those of residential heat pumps. A set of breadboard prototype microchannel evaporators and gas coolers was developed and tested. The refrigerant in the heat exchangers followed a counter cross-flow path with respect to the airflow direction. The test conditions corresponded to the typical operating conditions of residential heat pumps. In addition, a second set of commercial microchannel evaporators and gas coolers was tested for a less comprehensive range of operating conditions. The test results were reduced and a comprehensive data analysis, including comparison with the previous studies in this field, was performed. Capacity and pressure drop of the evaporator and gas cooler for the range of parameters studied were analyzed and are documented in this report. A gas cooler performance prediction model based on non-dimensional parameters was also developed and results are discussed as well. In addition, in the present study, experiments were conducted to evaluate capacities and pressure drops for sub-critical CO{sub 2} flow boiling and transcritical CO{sub 2} gas cooling in microchannel heat exchangers. An extensive review of the literature failed to indicate any previous systematic study in this area, suggesting a lack of fundamental understanding of the phenomena and a lack of comprehensive data that would quantify the performance potential of CO{sub 2} microchannel heat exchangers for the application at hand. All experimental tests were successfully conducted with an energy balance within {+-}3%. The only exceptions to this were experiments at very low saturation temperatures (-23 C), where energy balances were as high as 10%. In the case of evaporators, it was found that a lower saturation temperature (especially when moisture condensation occurs) improves the overall heat transfer coefficient

  13. Fabrication of monolithic microfluidic channels in diamond with ion beam lithography

    Science.gov (United States)

    Picollo, F.; Battiato, A.; Boarino, L.; Ditalia Tchernij, S.; Enrico, E.; Forneris, J.; Gilardino, A.; Jakšić, M.; Sardi, F.; Skukan, N.; Tengattini, A.; Olivero, P.; Re, A.; Vittone, E.

    2017-08-01

    In the present work, we report on the monolithic fabrication by means of ion beam lithography of hollow micro-channels within a diamond substrate, to be employed for microfluidic applications. The fabrication strategy takes advantage of ion beam induced damage to convert diamond into graphite, which is characterized by a higher reactivity to oxidative etching with respect to the chemically inert pristine structure. This phase transition occurs in sub-superficial layers thanks to the peculiar damage profile of MeV ions, which mostly damage the target material at their end of range. The structures were obtained by irradiating commercial CVD diamond samples with a micrometric collimated C+ ion beam at three different energies (4 MeV, 3.5 MeV and 3 MeV) at a total fluence of 2 × 1016 cm-2. The chosen multiple-energy implantation strategy allows to obtain a thick box-like highly damaged region ranging from 1.6 μm to 2.1 μm below the sample surface. High-temperature annealing was performed to both promote the graphitization of the ion-induced amorphous layer and to recover the pristine crystalline structure in the cap layer. Finally, the graphite was removed by ozone etching, obtaining monolithic microfluidic structures. These prototypal microfluidic devices were tested injecting aqueous solutions and the evidence of the passage of fluids through the channels was confirmed by confocal fluorescent microscopy.

  14. Monolithic Time Delay Integrated APD Arrays Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The overall goal of the proposed program by Epitaxial Technologies is to develop monolithic time delay integrated avalanche photodiode (APD) arrays with sensitivity...

  15. Fabrication of Pneumatic Microvalve for Tall Microchannel Using Inclined Lithography

    Directory of Open Access Journals (Sweden)

    Maho Kaminaga

    2016-12-01

    Full Text Available We used inclined lithography to fabricate a pneumatic microvalve for tall microchannels such as those used to convey large cells. The pneumatic microvalve consists of three layers. The upper layer is the actual liquid microchannel, which has a parallelogram-shaped cross section of width 500 μm, height 100 μm, and an acute angle of 53.6°. The lower layer is a pneumatic microchannel that functions as an actuator, and the middle layer is a thin polydimethylsiloxane membrane between the upper and lower layers. The operation of the pneumatic microchannel actuator causes the thin membrane to bend, resulting in the bending of the liquid microchannel and its closure. It was confirmed that the closure of the liquid microchannel completely stopped the flow of the HeLa cell suspension that was used to demonstrate the operation of the microvalve. The HeLa cells that passed through the microchannel were also observed to retain their proliferation and morphological properties.

  16. Inertial particle focusing in microchannels with gradually changing geometrical structures

    Science.gov (United States)

    Fan, Liang-Liang; Yan, Qing; Guo, Jing; Zhao, Hong; Zhao, Liang; Zhe, Jiang

    2017-01-01

    The influence of gradually changing geometrical structures on the inertial focusing of particles is systematically investigated by numerical simulations and experiments in this paper. The Saffman lift force, often ignored in the straight microchannel, becomes strong in microchannels with gradually changing geometrical structures, affecting the lateral migration of particles in the microchannels. In comparison with microchannels that have straight and gradually constricting structures, microchannels with gradually expanding structures focus all the particles in a much narrower bandwidth due to the combined effect of the Saffman lift force and the inertial lift force at the appropriate flow rates. Additionally, the influence of the different arrangements of gradually expanding structures on the inertial focusing of particles was also studied. Results suggest that to achieve the single-stream inertial focusing of particles, gradually expanding structures should be designed on one side or symmetrically on two sides of the microchannel. This study is of importance for the better design of the microchannels utilized for the efficient separation and manipulation of particle-related applications, such as microflow cytometry.

  17. Activated Carbon Fiber Monoliths as Supercapacitor Electrodes

    Directory of Open Access Journals (Sweden)

    Gelines Moreno-Fernandez

    2017-01-01

    Full Text Available Activated carbon fibers (ACF are interesting candidates for electrodes in electrochemical energy storage devices; however, one major drawback for practical application is their low density. In the present work, monoliths were synthesized from two different ACFs, reaching 3 times higher densities than the original ACFs’ apparent densities. The porosity of the monoliths was only slightly decreased with respect to the pristine ACFs, the employed PVDC binder developing additional porosity upon carbonization. The ACF monoliths are essentially microporous and reach BET surface areas of up to 1838 m2 g−1. SEM analysis reveals that the ACFs are well embedded into the monolith structure and that their length was significantly reduced due to the monolith preparation process. The carbonized monoliths were studied as supercapacitor electrodes in two- and three-electrode cells having 2 M H2SO4 as electrolyte. Maximum capacitances of around 200 F g−1 were reached. The results confirm that the capacitance of the bisulfate anions essentially originates from the double layer, while hydronium cations contribute with a mixture of both, double layer capacitance and pseudocapacitance.

  18. Forced—Flow Convection for Liquid Methanol Flowing through Microchannels

    Institute of Scientific and Technical Information of China (English)

    X.F.Peng; B.X.Wang

    1993-01-01

    Experiments were conducted to investigate the single phase forced-flow convection of methanol flowing through microchannels with rectangular cross-section.The fully-developed turbulent convection regime was found to be initiated at about Re=1000-1500,The fully developed turbulent heat transfer can be predicted by the well-known Dittus-Boelter correlation with mere modification of the original empirical constant coefficient 0.023 to 0.00805.The transition and laminar heat transfer behaviors in microchannels are highly peculiar and complicated,and heavily affected by liquid temperature,velocity and microchannel size.

  19. Design of a microchannel-nanochannel-microchannel array based nanoelectroporation system for precise gene transfection.

    Science.gov (United States)

    Gao, Keliang; Li, Lei; He, Lingna; Hinkle, Kevin; Wu, Yun; Ma, Junyu; Chang, Lingqian; Zhao, Xi; Perez, Daniel Gallego; Eckardt, Sigrid; McLaughlin, John; Liu, Boyu; Farson, Dave F; Lee, L James

    2014-03-12

    A micro/nano-fabrication process of a nanochannel electroporation (NEP) array and its application for precise delivery of plasmid for non-viral gene transfection is described. A dip-combing device is optimized to produce DNA nanowires across a microridge array patterned on the polydimethylsiloxane (PDMS) surface with a yield up to 95%. Molecular imprinting based on a low viscosity resin, 1,4-butanediol diacrylate (1,4-BDDA), adopted to convert the microridge-nanowire-microridge array into a microchannel-nanochannel-microchannel (MNM) array. Secondary machining by femtosecond laser ablation is applied to shorten one side of microchannels from 3000 to 50 μm to facilitate cell loading and unloading. The biochip is then sealed in a packaging case with reservoirs and microfluidic channels to enable cell and plasmid loading, and to protect the biochip from leakage and contamination. The package case can be opened for cell unloading after NEP to allow for the follow-up cell culture and analysis. These NEP cases can be placed in a spinning disc and up to ten discs can be piled together for spinning. The resulting centrifugal force can simultaneously manipulate hundreds or thousands of cells into microchannels of NEP arrays within 3 minutes. To demonstrate its application, a 13 kbp OSKM plasmid of induced pluripotent stem cell (iPSC) is injected into mouse embryonic fibroblasts cells (MEFCs). Fluorescence detection of transfected cells within the NEP biochips shows that the delivered dosage is high and much more uniform compared with similar gene transfection carried out by the conventional bulk electroporation (BEP) method.

  20. Internal modification of poly(dimethylsiloxane) microchannels with a borosilicate glass coating.

    Science.gov (United States)

    Orhan, J-B; Parashar, V K; Flueckiger, J; Gijs, M A M

    2008-08-19

    We report on an original technique for the in situ coating of poly(dimethylsiloxane) (PDMS) microchannels with borosilicate glass, starting from an active nonaqueous and alkali-free precursor solution. By chemical reaction of this active solution inside the microchannel and subsequent thermal annealing, a protective and chemically inert glass borosilicate coating is bonded to the PDMS. Attenuated total reflectance Fourier transform infrared (ATR-FTIR) spectroscopy and nuclear magnetic resonance spectroscopy of the active solution show that it is composed of a silicon oxide network with boron connectivity. Thermal gravimetric analysis demonstrates the absence of organic content when curing is done above 150 degrees C. The borosilicate nature of the glass coating covalently bonded to the PDMS is demonstrated using ATR-FTIR spectroscopy and X-ray photoelectron spectroscopy. Atomic force microscopy and scanning electron microscopy show a smooth and crack-free coating. The latter is used as an efficient protective barrier against diffusion in PDMS of fluorescent rhodamine B dye that is dissolved either in water or in toluene. Moreover, the coating prevents swelling and consequent structural damage of the PDMS when the latter is exposed to harsh chemicals such as toluene.

  1. Integrated cooling devices in silicon technology

    Science.gov (United States)

    Perret, C.; Avenas, Y.; Gillot, Ch.; Boussey, J.; Schaeffer, Ch.

    2002-05-01

    Silicon technology has become a good alternative to copper for the elaboration of efficient cooling devices required in power electronics domain. Owing to its high degree of miniaturization, it is expected to provide suitable microchannels and other inlets holes that were not achievable by copper micromachining. Besides, the use of silicon technology provides a variety of bare materials (silicon dioxide, silicon nitride, silicide, etc.) which may be either insulator or conductive, with a good or bad thermal conductivity. This large choice makes it possible to built up rather complex multilayer devices with mechanical properties good enough in comparison with hybrid copper technology heat sinks. Nevertheless, the use of silicon technology, where the microchannel width may reach few tens of microns, raises fundamental features concerning the fluid displacement within such small sections. More precisely, fundamental fluid mechanics studies have to be conducted out in order to get an accurate description of the fluid boundary layers and to provide basic data on the exchange mechanisms occurring at these surfaces. In this paper, we review the operation principles of both single- and double-phase heat exchange devices elaborated in silicon technology. Forced-convection heat sinks as well as integrated micro heat pipes are analyzed. An analytical approach is adopted to evaluate their total thermal resistances as a function of several geometrical parameters. Numerical simulations are then used in order to assess the accuracy of the analytical approach and to evaluate the impact of the fluidic aspects on the whole performance. The optimum devices are then conceived thanks to an appropriate optimization procedure taken into account the several experimental constraints. Reference values of similar copper devices are reminded and the advantages of the silicon integrated approach are highlighted.

  2. A Monolithic High-G SOI-MEMS Accelerometer for Measuring Projectile Launch and Flight Accelerations

    Directory of Open Access Journals (Sweden)

    Bradford S. Davis

    2006-01-01

    Full Text Available Analog Devices (ADI has designed and fabricated a monolithic high-g acceleration sensor (ADXSTC3-HG fabricated with the ADI silicon-on-insulator micro-electro-mechanical system (SOI-MEMS process. The SOI-MEMS sensor structure has a thickness of 10 um, allowing for the design of inertial sensors with excellent cross-axis rejection. The high-g accelerometer discussed in this paper was designed to measure in-plane acceleration to 10,000 g while subjected to 100,000 g in the orthogonal axes. These requirements were intended to meet Army munition applications. The monolithic sensor was packaged in an 8-pin leadless chip carrier (LCC-8 and was successfully demonstrated by the US Army Research Laboratory (ARL as part of an inertial measurement unit during an instrumented flight experiment of artillery projectiles launched at 15,000 g.

  3. Monolithic photonic integration of suspended light emitting diode, waveguide and photodetector

    CERN Document Server

    Wang, Yongjin; Gao, Xumin; Cai, Wei; Xu, Yin; Yuan, Jialei; Zhu, Guixia; Yang, Yongchao; Cao, Xun; Zhu, Hongbo; Gruenberg, Peter

    2015-01-01

    We report here a monolithic photonic integration of light emitting diode (LED) with waveguide and photodetector to build a highly-integrated photonic system to perform functionalities on the GaN-on-silicon platform. Suspended p-n junction InGaN/GaN multiple quantum wells (MQWs) are used for device fabrication. Part of the LED emission is coupled into suspended waveguide and then, the guided light laterally propagates along the waveguide and is finally sensed by the photodetector. Planar optical communication experimentally demonstrates that the proof-of-concept monolithic photonic integration system can achieve the on-chip optical interconnects. This work paves the way towards novel active electro-optical sensing system and planar optical communication in the visible range.

  4. Smart Sensing Strip Using Monolithically Integrated Flexible Flow Sensor for Noninvasively Monitoring Respiratory Flow.

    Science.gov (United States)

    Jiang, Peng; Zhao, Shuai; Zhu, Rong

    2015-12-15

    This paper presents a smart sensing strip for noninvasively monitoring respiratory flow in real time. The monitoring system comprises a monolithically-integrated flexible hot-film flow sensor adhered on a molded flexible silicone case, where a miniaturized conditioning circuit with a Bluetooth4.0 LE module are packaged, and a personal mobile device that wirelessly acquires respiratory data transmitted from the flow sensor, executes extraction of vital signs, and performs medical diagnosis. The system serves as a wearable device to monitor comprehensive respiratory flow while avoiding use of uncomfortable nasal cannula. The respiratory sensor is a flexible flow sensor monolithically integrating four elements of a Wheatstone bridge on single chip, including a hot-film resistor, a temperature-compensating resistor, and two balancing resistors. The monitor takes merits of small size, light weight, easy operation, and low power consumption. Experiments were conducted to verify the feasibility and effectiveness of monitoring and diagnosing respiratory diseases using the proposed system.

  5. MONOLITHIC ACTIVE PIXEL MATRIX WITH BINARY COUNTERS IN AN SOI PROCESS.

    Energy Technology Data Exchange (ETDEWEB)

    DUPTUCH,G.; YAREMA, R.

    2007-06-07

    The design of a Prototype monolithic active pixel matrix, designed in a 0.15 {micro}m CMOS SOI Process, is presented. The process allowed connection between the electronics and the silicon volume under the layer of buried oxide (BOX). The small size vias traversing through the BOX and implantation of small p-type islands in the n-type bulk result in a monolithic imager. During the acquisition time, all pixels register individual radiation events incrementing the counters. The counting rate is up to 1 MHz per pixel. The contents of counters are shifted out during the readout phase. The designed prototype is an array of 64 x 64 pixels and the pixel size is 26 x 26 {micro}m{sup 2}.

  6. Thermal neutron imaging using microchannel plates

    Science.gov (United States)

    Fraser, George W.; Pearson, James F.; Al-Horayess, O. S.; Feller, W. Bruce; Cook, Lee M.

    1993-02-01

    Microchannel plates (MCPs) are compact electron multipliers of high gain, widely used for the high resolution imaging of charged particles and photons. In this paper, we consider the use of lead glass MCPs for the imaging of thermal neutrons. Two contrasting techniques are described. The first method involves direct neutron detection within a special channel plate structure containing lithium and/or boron. We review the constraints of glass chemistry on the attainable lithium oxide and boron oxide fractions and, hence, on the maximum neutron detection efficiency. The second method involves the detection, using MCPs of standard glass composition, of the internal conversion electrons from a thin gadolinium foil. We present the first measurements of the detection efficiency, pulse height resolution and imaging properties of a pulse-counting MCP/Gd detector system.

  7. Dispersion of Suspensions in Unsteady Microchannel Flows

    Science.gov (United States)

    Maxey, Martin; Howard, Amanda; Winklerprins, Lukas; Tripathi, Anubhuv; Yeo, Kyongmin

    2013-11-01

    We explore the dispersion of non-Brownian (Pe >> 1) suspensions in unsteady, low Reynolds number shear flows in a microchannel. Prior experimental work on oscillating Couette flows and Poiseuille flows has shown the importance of strain amplitude in determining the long term distribution of particles across the channel. We will present results from numerical simulations for the early development of these flows and the motion of finite length suspension plugs. The distortion of a plug by the shear flow results in inhomogeneous particle fluxes across the channel. This is largely reversible over the course of a full cycle, giving reversibility in the bulk. Self-diffusion gives irreversibility though at the microscale. As the strain amplitude increases or the initial volume fraction increases irreversibility in the bulk is seen. The dynamics behind these processes and the role of particle pressure will be noted, together with related experimental observations.

  8. Improved lifetime of microchannel-plate PMTs

    Energy Technology Data Exchange (ETDEWEB)

    Lehmann, A., E-mail: lehmann@physik.uni-erlangen.de [Physikalisches Institut IV, Friedrich Alexander-University of Erlangen-Nuremberg, Erlangen (Germany); Britting, A.; Eyrich, W.; Uhlig, F. [Physikalisches Institut IV, Friedrich Alexander-University of Erlangen-Nuremberg, Erlangen (Germany); Dzhygadlo, R.; Gerhardt, A.; Götzen, K.; Höhler, R.; Kalicy, G.; Kumawat, H.; Lehmann, D.; Lewandowski, B.; Patsyuk, M.; Peters, K.; Schepers, G.; Schmitt, L.; Schwarz, C.; Schwiening, J.; Traxler, M.; Zühlsdorf, M. [GSI Helmholtzzentrum für Schwerionenforschung GmbH, Darmstadt (Germany); and others

    2014-12-01

    The charged particle identification at the PANDA experiment will be mainly performed with DIRC detectors. Because of their advantageous properties the preferred photon sensors are MCP-PMTs. However, until recently these devices showed serious aging problems which resulted in a diminishing quantum efficiency (QE) of the photo cathode. By applying innovative countermeasures against the aging causes, the manufacturers recently succeeded in drastically improving the lifetime of MCP-PMTs. Especially the application of an ALD coating technique to seal the material of the micro-channels proves very powerful and results in a lifetime of ≈6C/cm{sup 2} integrated anode charge without a substantial QE degradation for the latest PHOTONIS XP85112. This paper will present a comparative measurement of the lifetime of several older and recent MCP-PMTs demonstrating this progress.

  9. X-ray focusing using microchannel plates

    Science.gov (United States)

    Kaaret, P.; Geissbuehler, P.; Chen, A.; Glavinas, E.

    1992-01-01

    We present measurements of the X-ray focusing properties of square-pore microchannel plates (MCP's). Square-pore MCP's contain large numbers of closely packed optical surfaces, as required for grazing incidence X-ray optics. The surface of individual MCP channels has been measured and found to have high microroughness transverse to the channel axis and low microroughness parallel to the axis. The high frequency transverse roughness, on length scales greater than 400 nm, has a rms value of 5.9 nm and a Gaussian autocorrelation function with correlation length of 1.41 micron. We find that the geometric misalignments of the surfaces of different channels limit the angular resolution obtainable with current samples of MCP's to 7.1 arcmin.

  10. Microchannel plate modal gain variations with temperature

    Science.gov (United States)

    Slater, David C.; Timothy, J. G.

    1993-01-01

    Measurements of the modal gain of two high-gain curved-channel microchannel plates (MCPs) at various operating temperatures are presented. Both MCPs were fabricated from the Long Life glass with 12-micron diam channels on 15-micron centers. The modal gain was found to decrease with increasing temperature at a rate of -0.1 percent C. This reduction of gain with temperature is attributed primarily to an axial temperature gradient along each MCP channel creating a nonuniform electric field within the channel that lowers the effective output gain. A lowering of the secondary electron yield resulting from increased phonon scattering of secondary electrons released within the walls of the MCP channels was assessed, but was found to have a negligible contribution to the drop in gain with temperature.

  11. Low noise and conductively cooled microchannel plates

    Science.gov (United States)

    Feller, W. B.

    1990-01-01

    Microchannel plate (MCP) dynamic range has recently been enhanced for both very low and very high input flux conditions. Improvements in MCP manufacturing technology reported earlier have led to MCPs with substantially reduced radioisotope levels, giving dramatically lower internal background-counting rates. An update is given on the Galileo low noise MCP. Also, new results in increasing the MCP linear counting range for high input flux densities are presented. By bonding the active face of a very low resistance MCP (less than 1 megaohm) to a substrate providing a conductive path for heat transport, the bias current limit (hence, MCP output count rate limit) can be increased up to two orders of magnitude. Normal pulse-counting MCP operation was observed at bias currents of several mA when a curved-channel MCP (80:1) was bonded to a ceramic multianode substrate; the MCP temperature rise above ambient was less than 40 C.

  12. Improved lifetime of microchannel-plate PMTs

    Science.gov (United States)

    Lehmann, A.; Britting, A.; Eyrich, W.; Uhlig, F.; Dzhygadlo, R.; Gerhardt, A.; Götzen, K.; Höhler, R.; Kalicy, G.; Kumawat, H.; Lehmann, D.; Lewandowski, B.; Patsyuk, M.; Peters, K.; Schepers, G.; Schmitt, L.; Schwarz, C.; Schwiening, J.; Traxler, M.; Zühlsdorf, M.; Dodokhov, V. Kh.; Düren, M.; Föhl, K.; Hayrapetyan, A.; Kröck, B.; Merle, O.; Rieke, J.; Cowie, E.; Keri, T.; Montgomery, R.; Rosner, G.; Achenbach, P.; Cardinali, M.; Hoek, M.; Lauth, W.; Sfienti, C.; Thiel, M.; Bühler, P.; Gruber, L.; Marton, J.; Suzuki, K.

    2014-12-01

    The charged particle identification at the PANDA experiment will be mainly performed with DIRC detectors. Because of their advantageous properties the preferred photon sensors are MCP-PMTs. However, until recently these devices showed serious aging problems which resulted in a diminishing quantum efficiency (QE) of the photo cathode. By applying innovative countermeasures against the aging causes, the manufacturers recently succeeded in drastically improving the lifetime of MCP-PMTs. Especially the application of an ALD coating technique to seal the material of the micro-channels proves very powerful and results in a lifetime of ≈ 6 C /cm2 integrated anode charge without a substantial QE degradation for the latest PHOTONIS XP85112. This paper will present a comparative measurement of the lifetime of several older and recent MCP-PMTs demonstrating this progress.

  13. Monolithically integrated Ge CMOS laser

    Science.gov (United States)

    Camacho-Aguilera, Rodolfo

    2014-02-01

    Ge-on-Si devices are explored for photonic integration. Through the development of better growth techniques, monolithic integration, laser design and prototypes, it was possible to probe Ge light emitters with emphasis on lasers. Preliminary worked shows thermal photonic behavior capable of enhancing lamination at high temperatures. Increase luminescence is observed up to 120°C from L-band contribution. Higher temperatures show contribution from Δ -band. The increase carrier thermal contribution suggests high temperature applications for Ge light emitters. A Ge electrically pumped laser was probed under 0.2% biaxial strain and doping concentration ~4.5×1019cm-3 n-type. Ge pnn lasers exhibit a gain >1000cm-1 with 8mW power output, presenting a spectrum range of over 200nm, making Ge the ideal candidate for Si photonics. Large temperatures fluctuations and process limit the present device. Theoretically a gain of >4000cm- gain is possible with a threshold of as low as 1kA/cm2. Improvements in Ge work

  14. Surface cell immobilization within perfluoroalkoxy microchannels

    Energy Technology Data Exchange (ETDEWEB)

    Stojkovič, Gorazd; Krivec, Matic [Faculty of Chemistry and Chemical Technology, University of Ljubljana, Aškerčeva 5, SI-1000 Ljubljana (Slovenia); Vesel, Alenka [Jožef Stefan Institute, Jamova cesta 39, 1000 Ljubljana (Slovenia); Marinšek, Marjan [Faculty of Chemistry and Chemical Technology, University of Ljubljana, Aškerčeva 5, SI-1000 Ljubljana (Slovenia); Žnidaršič-Plazl, Polona, E-mail: polona.znidarsic@fkkt.uni-lj.si [Faculty of Chemistry and Chemical Technology, University of Ljubljana, Aškerčeva 5, SI-1000 Ljubljana (Slovenia)

    2014-11-30

    Graphical abstract: - Highlights: • A very efficient approach for immobilization of cells into microreactors is presented. • It is applicable to various materials, including PFA and cyclic olefin (co)polymers. • It was used to immobilize different prokaryotic and eukaryotic microbes. • Cells were immobilized on the surface in high density and showed good stability. • Mechanisms of APTES interactions with target materials are proposed. - Abstract: Perfluoroalkoxy (PFA) is one of the most promising materials for the fabrication of cheap, solvent resistant and reusable microfluidic chips, which have been recently recognized as effective tools for biocatalytic process development. The application of biocatalysts significantly depends on efficient immobilization of enzymes or cells within the reactor enabling long-term biocatalyst use. Functionalization of PFA microchannels by 3-aminopropyltriethoxysilane (ATPES) and glutaraldehyde was used for rapid preparation of microbioreactors with surface-immobilized cells. X-ray photoelectron spectroscopy and scanning electron microscopy were used to accurately monitor individual treatment steps and to select conditions for cell immobilization. The optimized protocol for Saccharomyces cerevisiae immobilization on PFA microchannel walls comprised ethanol surface pretreatment, 4 h contacting with 10% APTES aqueous solution, 10 min treatment with 1% glutaraldehyde and 20 min contacting with cells in deionized water. The same protocol enabled also immobilization of Escherichia coli, Pseudomonas putida and Bacillus subtilis cells on PFA surface in high densities. Furthermore, the developed procedure has been proved to be very efficient also for surface immobilization of tested cells on other materials that are used for microreactor fabrication, including glass, polystyrene, poly (methyl methacrylate), polycarbonate, and two olefin-based polymers, namely Zeonor{sup ®} and Topas{sup ®}.

  15. Microchannel Reactors for ISRU Applications Using Nanofabricated Catalysts Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Makel Engineering, Inc. (MEI) and USRA propose to develop microchannel reactors for In-Situ Resources Utilization (ISRU) using nanofabricated catalysts. The proposed...

  16. Micro-Channel Embedded Pulsating Heat Pipes Project

    Data.gov (United States)

    National Aeronautics and Space Administration — As the need for thermal control technology becomes more demanding Micro-Channel Embedded Pulsating Heat Pipes (ME-PHPs) represents a sophisticated and enabling...

  17. Nanosecond-gating properties of proximity-focused microchannel-plate image intensifiers

    Science.gov (United States)

    King, N. S. P.; Yates, G. J.; Jaramillo, S. A.; Ogle, J. W.

    Some fundamental properties of 18 mm-diam gated proximity focussed microchannel plate (MCP) image intensifiers used as fast image shutters in the 1 to 10 ns range were identified and studied. Light pulses from a modelocked dye laser optically sample the gated MCP. Shuttering is achieved by applying a forward biasing electrical gate pulse to the quiescently reverse-biased photocathode MCP interface. Variable delay between the gate pulse and the laser pulse permits tracing the MCP's optical response. Gating speeds, turn-on and turn-off patterns, the asymmetric spatial depedence of the MCP optical response, and resolution effects as functions of gate pulse width and photocathode-MCP bias were characterized. Variations in the intensity profiles of the phosphor's spatial response for uniform photocathode illumination are measured with a calibrated silicon intensified target focus projection, scan television camera and a high speed video digitizer while photomultipliers monitor the laser pulse and the phosphor's spatially integrated output intensities.

  18. Microporous microchannel plates and method of manufacturing same

    Energy Technology Data Exchange (ETDEWEB)

    Beetz, C.P. Jr.; Boerstler, R.W.; Steinbeck, J.; Winn, D.R.

    2000-04-04

    A microchannel plate and method of manufacturing same is provided. The microchannel plate includes a plate consisting of an anodized material and a plurality of channels which are formed during the anodization of the material and extend between the two sides of the plate. Electrodes are also disposed on each side of the plate for generating an electrical field within the channels. Preferably, the material is alumina and the channels are activated such that the channel walls are conductive and highly secondary emissive.

  19. Microporous microchannel plates and method of manufacturing same

    Energy Technology Data Exchange (ETDEWEB)

    Beetz, Jr., Charles P. (New Milford, CT); Boerstler, Robert W. (Woodbury, CT); Steinbeck, John (Fitzwilliam, NH); Winn, David R. (Wilton, CT)

    2000-01-01

    A microchannel plate and method of manufacturing same is provided. The microchannel plate includes a plate consisting of an anodized material and a plurality of channels which are formed during the anodization of the material and extend between the two sides of the plate. Electrodes are also disposed on each side of the plate for generating an electrical field within the channels. Preferably, the material is alumina and the channels are activated such that the channel walls are conductive and highly secondary emissive.

  20. Microporous microchannel plates and method of manufacturing same

    Science.gov (United States)

    Beetz, Jr., Charles P.; Boerstler, Robert W.; Steinbeck, John; Winn, David R.

    2000-01-01

    A microchannel plate and method of manufacturing same is provided. The microchannel plate includes a plate consisting of an anodized material and a plurality of channels which are formed during the anodization of the material and extend between the two sides of the plate. Electrodes are also disposed on each side of the plate for generating an electrical field within the channels. Preferably, the material is alumina and the channels are activated such that the channel walls are conductive and highly secondary emissive.

  1. Laminated microchannel devices, mixing units and method of making same

    Science.gov (United States)

    Bennett, Wendy D [Kennewick, WA; Hammerstrom, Donald J [West Richland, WA; Martin, Peter M [Kennewick, WA; Matson, Dean W [Kennewick, WA

    2002-10-17

    A laminated microchannel device is described in which there is a unit operation process layer that has longitudinal channel. The longitudinal channel is cut completely through the layer in which the unit process operation resides. Both the device structure and method of making the device provide significant advantages in terms of simplicity and efficiency. A static mixing unit that can be incorporated in the laminated microchannel device is also described.

  2. Microchip-based monolithic column for high performance liquid chromatography Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Fabricate the microchannels using DDL facilities. Develop a process for in situ polymerization inside the microchannels and optimize the chemistry Perform separation...

  3. Silicon fabric for multi-functional applications

    KAUST Repository

    Sevilla, Galo T.

    2013-06-01

    This paper reports a generic process flow to fabricate mechanically flexible and optically semi-transparent thermoelectric generators (TEGs), micro lithium-ion batteries (μLIB) and metal-oxide-semiconductor capacitors (MOSCAPs) on mono-crystalline silicon fabric platforms from standard bulk silicon (100) wafers. All the fabricated devices show outstanding mechanical flexibility and performance, making an important step towards monolithic integration of Energy Chip (self-powered devices) including energy harvesters and electronic devices on flexible platforms. We also report a recyclability process for the remaining bulk substrate after release, allowing us to achieve a low cost flexible platform for high performance applications. © 2013 IEEE.

  4. Chaos analysis of viscoelastic chaotic flows of polymeric fluids in a micro-channel

    Energy Technology Data Exchange (ETDEWEB)

    Lim, C. P.; Lam, Y. C., E-mail: myclam@ntu.edu.sg [School of Mechanical and Aerospace Engineering, Nanyang Technological University, 639798 (Singapore); BioSystems and Micromechanics (BioSyM) IRG, Singapore-MIT Alliance for Research and Technology (SMART) Centre, 138602 (Singapore); Han, J. [BioSystems and Micromechanics (BioSyM) IRG, Singapore-MIT Alliance for Research and Technology (SMART) Centre, 138602 (Singapore); Department of Electrical Engineering and Computer Science, Massachusetts Institute of Technology, Cambridge, MA 02139 (United States); Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139 (United States)

    2015-07-15

    Many fluids, including biological fluids such as mucus and blood, are viscoelastic. Through the introduction of chaotic flows in a micro-channel and the construction of maps of characteristic chaos parameters, differences in viscoelastic properties of these fluids can be measured. This is demonstrated by creating viscoelastic chaotic flows induced in an H-shaped micro-channel through the steady infusion of a polymeric fluid of polyethylene oxide (PEO) and another immiscible fluid (silicone oil). A protocol for chaos analysis was established and demonstrated for the analysis of the chaotic flows generated by two polymeric fluids of different molecular weight but with similar relaxation times. The flows were shown to be chaotic through the computation of their correlation dimension (D{sub 2}) and the largest Lyapunov exponent (λ{sub 1}), with D{sub 2} being fractional and λ{sub 1} being positive. Contour maps of D{sub 2} and λ{sub 1} of the respective fluids in the operating space, which is defined by the combination of polymeric fluids and silicone oil flow rates, were constructed to represent the characteristic of the chaotic flows generated. It was observed that, albeit being similar, the fluids have generally distinct characteristic maps with some similar trends. The differences in the D{sub 2} and λ{sub 1} maps are indicative of the difference in the molecular weight of the polymers in the fluids because the driving force of the viscoelastic chaotic flows is of molecular origin. This approach in constructing the characteristic maps of chaos parameters can be employed as a diagnostic tool for biological fluids and, more generally, chaotic signals.

  5. Chaos analysis of viscoelastic chaotic flows of polymeric fluids in a micro-channel

    Directory of Open Access Journals (Sweden)

    C. P. Lim

    2015-07-01

    Full Text Available Many fluids, including biological fluids such as mucus and blood, are viscoelastic. Through the introduction of chaotic flows in a micro-channel and the construction of maps of characteristic chaos parameters, differences in viscoelastic properties of these fluids can be measured. This is demonstrated by creating viscoelastic chaotic flows induced in an H-shaped micro-channel through the steady infusion of a polymeric fluid of polyethylene oxide (PEO and another immiscible fluid (silicone oil. A protocol for chaos analysis was established and demonstrated for the analysis of the chaotic flows generated by two polymeric fluids of different molecular weight but with similar relaxation times. The flows were shown to be chaotic through the computation of their correlation dimension (D2 and the largest Lyapunov exponent (λ1, with D2 being fractional and λ1 being positive. Contour maps of D2 and λ1 of the respective fluids in the operating space, which is defined by the combination of polymeric fluids and silicone oil flow rates, were constructed to represent the characteristic of the chaotic flows generated. It was observed that, albeit being similar, the fluids have generally distinct characteristic maps with some similar trends. The differences in the D2 and λ1 maps are indicative of the difference in the molecular weight of the polymers in the fluids because the driving force of the viscoelastic chaotic flows is of molecular origin. This approach in constructing the characteristic maps of chaos parameters can be employed as a diagnostic tool for biological fluids and, more generally, chaotic signals.

  6. Development of a Microchannel In Situ Propellant Production System

    Science.gov (United States)

    Brooks, Kriston; Rassat, Scot; Hu, John; Stenkamp, Susie; Schlahta, Steve; Bontha, Jagan; Holladay, Jamie; Simon, Tom; Romig, Kris; Howard, Candice

    2006-01-01

    A microchannel-based system is being developed for NASA to produce propellants from atmospheric CO2 on Mars. This system will provide a means of reducing the earth-based launch mass for both sample return and human exploration missions. The atmospheric CO2 will be collected, separated, and compressed with a microchannel thermal swing adsorption system. It will be reacted with hydrogen that has either been electrolyzed from the available subsurface water or brought from earth. Methane and water will be produced by using microchannel Sabatier and Reverse Water Gas Shift reactors, respectively. The water will then separated with a microchannel condenser/phase separator and electrolyzed to produce oxygen and hydrogen. Feed gases will be separated from the products and recycled. The system design requirements will be presented in this paper. The design and fabrication methods of the microchannel CO2 sorption pump, reactors, and phase separators will be described, and the advantages of microchannel architecture will be delineated for each component. Estimates of system mass and volume will also be provided in comparison to conventional hardware. The testing and integration proposed during this project to meet NASA's Technology Readiness Level 5 will also be presented.

  7. A High Resolution Monolithic Crystal, DOI, MR Compatible, PET Detector

    Energy Technology Data Exchange (ETDEWEB)

    Robert S Miyaoka

    2012-03-06

    The principle objective of this proposal is to develop a positron emission tomography (PET) detector with depth-of-interaction (DOI) positioning capability that will achieve state of the art spatial resolution and sensitivity performance for small animal PET imaging. When arranged in a ring or box detector geometry, the proposed detector module will support <1 mm3 image resolution and >15% absolute detection efficiency. The detector will also be compatible with operation in a MR scanner to support simultaneous multi-modality imaging. The detector design will utilize a thick, monolithic crystal scintillator readout by a two-dimensional array of silicon photomultiplier (SiPM) devices using a novel sensor on the entrance surface (SES) design. Our hypothesis is that our single-ended readout SES design will provide an effective DOI positioning performance equivalent to more expensive dual-ended readout techniques and at a significantly lower cost. Our monolithic crystal design will also lead to a significantly lower cost system. It is our goal to design a detector with state of the art performance but at a price point that is affordable so the technology can be disseminated to many laboratories. A second hypothesis is that using SiPM arrays, the detector will be able to operate in a MR scanner without any degradation in performance to support simultaneous PET/MR imaging. Having a co-registered MR image will assist in radiotracer localization and may also be used for partial volume corrections to improve radiotracer uptake quantitation. The far reaching goal of this research is to develop technology for medical research that will lead to improvements in human health care.

  8. Modified monolithic silica capillary for preconcentration of catecholamines

    Institute of Scientific and Technical Information of China (English)

    Wei Chang; Tusyo-shi Komazu

    2009-01-01

    Preconcentration of catecholamines by the modified monolithic silica in the capillary was investigated in this study. In order to achieve a microchip-based method for determining catecholamines in the saliva, the monolithic silica was fabricated in the capillary and the monolithic silica was chemically modified by on-column reaction with phenylboronate. Different modified methods were compared. The concentration conditions were optimized. This study indicates the applicability of the modified monolithic silica capillary when it was used to concentrate catecholamines.

  9. Modified monolithic silica capillary for preconcentration of catecholamines

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    Preconcentration of catecholamines by the modified monolithic silica in the capillary was investigated in this study. In order to achieve a microchip-based method for determining catecholamines in the saliva,the monolithic silica was fabricated in the capillary and the monolithic silica was chemically modified by on-column reaction with phenylboronate. Different modified methods were compared. The concentration conditions were optimized. This study indicates the applicability of the modified monolithic sili...

  10. Fracture resistance of monolithic zirconia molar crowns with reduced thickness

    OpenAIRE

    Nakamura, Keisuke; Harada, A.; Inagaki, R.; Kanno, Taro; Niwano, Y; Milleding, Percy; Ørtengren, Ulf Thore

    2015-01-01

    This is the accepted manuscript version. Published version is available at Acta Odontologica Scandinavica Objectives. The purpose of the present study was to analyze the relationship between fracture load of monolithic zirconia crowns and axial/occlusal thickness, and to evaluate the fracture resistance of monolithic zirconia crowns with reduced thickness in comparison with that of monolithic lithium disilicate crowns with regular thickness. Materials and methods. Monolithic zi...

  11. Development of a monolithic ferrite memory array

    Science.gov (United States)

    Heckler, C. H., Jr.; Bhiwandker, N. C.

    1972-01-01

    The results of the development and testing of ferrite monolithic memory arrays are presented. This development required the synthesis of ferrite materials having special magnetic and physical characteristics and the development of special processes; (1) for making flexible sheets (laminae) of the ferrite composition, (2) for embedding conductors in ferrite, and (3) bonding ferrite laminae together to form a monolithic structure. Major problems encountered in each of these areas and their solutions are discussed. Twenty-two full-size arrays were fabricated and fired during the development of these processes. The majority of these arrays were tested for their memory characteristics as well as for their physical characteristics and the results are presented. The arrays produced during this program meet the essential goals and demonstrate the feasibility of fabricating monolithic ferrite memory arrays by the processes developed.

  12. Carbon Fiber Composite Monoliths as Catalyst Supports

    Energy Technology Data Exchange (ETDEWEB)

    Contescu, Cristian I [ORNL; Gallego, Nidia C [ORNL; Pickel, Joseph M [ORNL; Blom, Douglas Allen [ORNL; Burchell, Timothy D [ORNL

    2006-01-01

    Carbon fiber composite monoliths are rigid bodies that can be activated to a large surface area, have tunable porosity, and proven performance in gas separation and storage. They are ideal as catalyst supports in applications where a rigid support, with open structure and easy fluid access is desired. We developed a procedure for depositing a dispersed nanoparticulate phase of molybdenum carbide (Mo2C) on carbon composite monoliths in the concentration range of 3 to 15 wt% Mo. The composition and morphology of this phase was characterized using X-ray diffraction and electron microscopy, and a mechanism was suggested for its formation. Molybdenum carbide is known for its catalytic properties that resemble those of platinum group metals, but at a lower cost. The materials obtained are expected to demonstrate catalytic activity in a series of hydrocarbon reactions involving hydrogen transfer. This project demonstrates the potential of carbon fiber composite monoliths as catalyst supports.

  13. Carbon Fiber Composite Monoliths for Catalyst Supports

    Energy Technology Data Exchange (ETDEWEB)

    Contescu, Cristian I [ORNL; Gallego, Nidia C [ORNL; Pickel, Joseph M [ORNL; Blom, Douglas Allen [ORNL; Burchell, Timothy D [ORNL

    2006-01-01

    Carbon fiber composite monoliths are rigid bodies that can be activated to a large surface area, have tunable porosity, and proven performance in gas separation and storage. They are ideal as catalyst supports in applications where a rigid support, with open structure and easy fluid access is desired. We developed a procedure for depositing a dispersed nanoparticulate phase of molybdenum carbide (Mo2C) on carbon composite monoliths in the concentration range of 3 to 15 wt% Mo. The composition and morphology of this phase was characterized using X-ray diffraction and electron microscopy, and a mechanism was suggested for its formation. Molybdenum carbide is known for its catalytic properties that resemble those of platinum group metals, but at a lower cost. The materials obtained are expected to demonstrate catalytic activity in a series of hydrocarbon reactions involving hydrogen transfer. This project demonstrates the potential of carbon fiber composite monoliths as catalyst supports.

  14. Eigenpolarization theory of monolithic nonplanar ring oscillators

    Science.gov (United States)

    Nilsson, Alan C.; Gustafson, Eric K.; Byer, Robert L.

    1989-01-01

    Diode-laser-pumped monolithic nonplanar ring oscillators (NPROs) in an applied magnetic field can operate as unidirectional traveling-wave lasers. The diode laser pumping, monolithic construction, and unidirectional oscillation lead to narrow linewidth radiation. Here, a comprehensive theory of the eigenpolarizations of a monolithic NPRO is presented. It is shown how the properties of the integral optical diode that forces unidirectional operation depend on the choice of the gain medium, the applied magnetic field, the output coupler, and the geometry of the nonplanar ring light path. Using optical equivalence theorems to gain insight into the polarization characteristics of the NPRO, a strategy for designing NPROs with low thresholds and large loss nonreciprocities is given. An analysis of the eigenpolarizations for one such NPRO is presented, alternative optimization approaches are considered, and the prospects for further reducing the linewidths of these lasers are briefly discussed.

  15. Physical and chemical sensing using monolithic semiconductor optical transducers

    Science.gov (United States)

    Zappe, Hans P.; Hofstetter, Daniel; Maisenhoelder, Bernd; Moser, Michael; Riel, Peter; Kunz, Rino E.

    1997-09-01

    We present two monolithically integrated optical sensor systems based on semiconductor photonic integrated circuits. These compact, robust and highly functional transducers perform all necessary optical and electro-optical functions on-chip; extension to multi-sensor arrays is easily envisaged. A monolithic Michelson interferometer for high-resolution displacement measurement and a monolithic Mach-Zehnder interferometer for refractometry are discussed.

  16. Increased thermal conductivity monolithic zeolite structures

    Science.gov (United States)

    Klett, James; Klett, Lynn; Kaufman, Jonathan

    2008-11-25

    A monolith comprises a zeolite, a thermally conductive carbon, and a binder. The zeolite is included in the form of beads, pellets, powders and mixtures thereof. The thermally conductive carbon can be carbon nano-fibers, diamond or graphite which provide thermal conductivities in excess of about 100 W/mK to more than 1,000 W/mK. A method of preparing a zeolite monolith includes the steps of mixing a zeolite dispersion in an aqueous colloidal silica binder with a dispersion of carbon nano-fibers in water followed by dehydration and curing of the binder is given.

  17. Characterization of CIM monoliths as enzyme reactors.

    Science.gov (United States)

    Vodopivec, Martina; Podgornik, Ales; Berovic, Marin; Strancar, Ales

    2003-09-25

    The immobilization of the enzymes citrate lyase, malate dehydrogenase, isocitrate dehydrogenase and lactate dehydrogenase to CIM monolithic supports was performed. The long-term stability, reproducibility, and linear response range of the immobilized enzyme reactors were investigated along with the determination of the kinetic behavior of the enzymes immobilized on the CIM monoliths. The Michaelis-Menten constant K(m) and the turnover number k(3) of the immobilized enzymes were found to be flow-unaffected. Furthermore, the K(m) values of the soluble and immobilized enzyme were found to be comparable. Both facts indicate the absence of a diffusional limitation in immobilized CIM enzyme reactors.

  18. Monolithically integrated optoelectronic down-converter (MIOD)

    Science.gov (United States)

    Portnoi, Efrim L.; Venus, G. B.; Khazan, A. A.; Gorfinkel, Vera B.; Kompa, Guenter; Avrutin, Evgenii A.; Thayne, Iain G.; Barrow, David A.; Marsh, John H.

    1995-06-01

    Optoelectronic down-conversion of very high-frequency amplitude-modulated signals using a semiconductor laser simultaneously as a local oscillator and a mixer is proposed. Three possible constructions of a monolithically integrated down-converter are considered theoretically: a four-terminal semiconductor laser with dual pumping current/modal gain control, and both a passively mode-locked and a passively Q-switched semiconductor laser monolithically integrated with an electroabsorption or pumping current modulator. Experimental verification of the feasibility of the concept of down conversion in a laser diode is presented.

  19. PDMS microchannel fabrication technique based on microwire-molding

    Institute of Scientific and Technical Information of China (English)

    JIA YueFei; JIANG JiaHuan; MA XiaoDong; LI Yuan; HUANG HeMing; CAI KunBao; CAI ShaoXi; WU YunPeng

    2008-01-01

    Micro-flow channel is basic functional component of microfluidic chip, and every step-forward of its construction technique has been receiving concern all over the world. This article presents a notcomplicated but flexible method for fabrication of micro-flow channels. This method mainly utilizes the conventional molding capability of polydimethylsiloxane (PDMS) and widespread commercial microwires as templates. We have fabricated out some conventional types of microchannels with different topological shapes, as examples for the demonstration of this flexible fabrication route which was not dependent on the stringent demands of photolithographical or microelectromechanical system (MEMS)techniques. The smooth surface, high-intensity, and high flexibility of the wires made it possible to create many types of topological structures of the two-dimensional or three-dimensional microchannel or channel array. The geometric shape of the cross-section of thus forming microchannel in PDMS was the negative of that of embedded-in microwire, in high-fidelity if suitable measures were taken. Moreover, such a microchannel fabrication process can easily integrate the conductivity and low resistivity of the metal wire to create micro-flow devices that are suitable for the electromagnetic control of liquid or the temperature regulation in the microchannel. Furthermore some preliminary optical analysis was provided for the observation of thus forming rounded microchannel. Based on this molding strategy,we even made some prototypes for functional microflow application, such as microsolenoids chip and temperature control gadgets. And an experiment of forming a droplet in the cross channel further confirmed the feasibility and applicability of this flexible microchannel forming technique.

  20. Efficient generation of ozone in arrays of microchannel plasmas

    Science.gov (United States)

    Kim, M. H.; Cho, J. H.; Ban, S. B.; Choi, R. Y.; Kwon, E. J.; Park, S.-J.; Eden, J. G.

    2013-07-01

    Ozone is produced efficiently in arrays of low-temperature, linear microplasmas having a trapezoidal or parabolic cross-sectional profile and generated within nanoporous alumina (Al2O3) microchannels. Fabricated from aluminum foil by wet chemical processing, micropowder ablation, and one photolithographic step, arrays of microchannel plasma devices 3 cm in length and 250 µm in width at the aperture of the channel produce spatially uniform glow discharges in O2 feedstock gas at a pressure of 1 atm and flow rates of 0.25-2.5 standard litres per minute. Several device and array structures, incorporating embedded electrodes and Al/Al2O3 or glass channels, have been fabricated and tested extensively. A design based solely on microchannels fabricated in nanoporous alumina, flanked by Al electrodes buried in the channel wall, is found to be superior in performance to other materials and geometries. Altering the electric field profile inside the microchannels (by means of the electrode geometry) is found to have a significant impact on the reactor efficiency. Ozone output is observed to scale linearly with the number of microchannels in the array and the feedstock gas flow rate. Efficiencies and O3 concentrations surpassing 85 g kWh-1 and 17 g m-3, respectively, have been measured, and arrays as large as 120 microchannels have been realized to date. The results presented here suggest a new approach to plasma-chemical reactors, one in which ‘massively parallel’ processing of one or more gases in non-streamer (glow) discharges efficiently produces products of commercial value in thousands of micropores or microchannels fabricated in recyclable and inexpensive materials. Reductions of an order of magnitude in the weight and volume of microplasma-based O3 reactors, relative to conventional dielectric barrier discharge technology, appear to be feasible.

  1. Si microchannel plates for image intensification

    Science.gov (United States)

    Smith, Arlynn W.; Beetz, Charles P., Jr.; Boerstler, Robert W.; Winn, D. R.; Steinbeck, John W.

    2000-11-01

    Glass microchannel plates (MCPs) have been in use by numerous manufactuers in a variety of electron multiplication applications. Conventional fabrication of MCPs follow the lines of glass drawing and etching technology. Core and clad glass are drawn together, stacked, drawn again, and finally stacked in the desired pattern. The soluble core is removed with wet chemical processing. These techniques are beginning to run into their feasible limits in terms of channel size, open area ratio, uniformity, and material issues. A strong desire exists to fabricate MCPs with accepted lithographic techniques using Si as the base material to improve uniformity and throughput. Open area ratios of as high as 95% have been achieved using lithography. However, attempts to meet other channel plate characteristics met with little success due to thermal runaway or arcing during operation, high voltage is required for electron gain. Processing improvements have lead to the complete oxidation of the Si matrix eliminating the conducting Si in the channel walls of the Si MCPs allowing high voltages to be supported. Complete oxidation of the Si to silica allows processing temperatures high than conventional glass matrices can withstand. This fact allows for high temperature growth of conductive and secondary emissive materials on the channel walls of the structure. Si MCPs with gain have now been fabricated and tested with voltages comparable to conventional glass MCPs. Channel plate characteristics such as operating voltage, strip current, and gain for Si MCPs will be presented and compared to glass MCPs.

  2. Inertial Focusing of Microparticles in Curvilinear Microchannels

    Science.gov (United States)

    Özbey, Arzu; Karimzadehkhouei, Mehrdad; Akgönül, Sarp; Gozuacik, Devrim; Koşar, Ali

    2016-12-01

    A passive, continuous and size-dependent focusing technique enabled by “inertial microfluidics”, which takes advantage of hydrodynamic forces, is implemented in this study to focus microparticles. The objective is to analyse the decoupling effects of inertial forces and Dean drag forces on microparticles of different sizes in curvilinear microchannels with inner radius of 800 μm and curvature angle of 280°, which have not been considered in the literature related to inertial microfluidics. This fundamental approach gives insight into the underlying physics of particle dynamics and offers continuous, high-throughput, label-free and parallelizable size-based particle separation. Our design allows the same footprint to be occupied as straight channels, which makes parallelization possible with optical detection integration. This feature is also useful for ultrahigh-throughput applications such as flow cytometers with the advantages of reduced cost and size. The focusing behaviour of 20, 15 and 10 μm fluorescent polystyrene microparticles was examined for different channel Reynolds numbers. Lateral and vertical particle migrations and the equilibrium positions of these particles were investigated in detail, which may lead to the design of novel microfluidic devices with high efficiency and high throughput for particle separation, rapid detection and diagnosis of circulating tumour cells with reduced cost.

  3. Microchannel plate special nuclear materials sensor

    Energy Technology Data Exchange (ETDEWEB)

    Feller, W.B., E-mail: bfeller@novascientific.com [Nova Scientific Inc., 10 Picker Road, Sturbridge, MA 01566 (United States); White, P.L.; White, P.B. [Nova Scientific Inc., 10 Picker Road, Sturbridge, MA 01566 (United States); Siegmund, O.H.W.; Martin, A.P.; Vallerga, J.V. [Sensor Sciences, 3333 Vincent Road, Pleasant Hill, CA 94523 (United States)

    2011-10-01

    Nova Scientific Inc., is developing for the Domestic Nuclear Detection Office (DNDO SBIR no. HSHQDC-08-C-00190), a solid-state, high-efficiency neutron detection alternative to {sup 3}He gas tubes, using neutron-sensitive microchannel plates (MCPs) containing {sup 10}B and/or Gd. This work directly supports DNDO development of technologies designed to detect and interdict nuclear weapons or illicit nuclear materials. Neutron-sensitized MCPs have been shown theoretically and more recently experimentally, to be capable of thermal neutron detection efficiencies equivalent to {sup 3}He gas tubes. Although typical solid-state neutron detectors typically have an intrinsic gamma sensitivity orders of magnitude higher than that of {sup 3}He gas detectors, we dramatically reduce gamma sensitivity by combining a novel electronic coincidence rejection scheme, employing a separate but enveloping gamma scintillator. This has already resulted in a measured gamma rejection ratio equal to a small {sup 3}He tube, without in principle sacrificing neutron detection efficiency. Ongoing improvements to the MCP performance as well as the coincidence counting geometry will be described. Repeated testing and validation with a {sup 252}Cf source has been underway throughout the Phase II SBIR program, with ongoing comparisons to a small commercial {sup 3}He gas tube. Finally, further component improvements and efforts toward integration maturity are underway, with the goal of establishing functional prototypes for SNM field testing.

  4. Diabatic flow boiling in circular transparent microchannels

    Science.gov (United States)

    Silvério, V.; Moreira, A. L. N.

    2012-11-01

    The horizontally assembled circular microchannel (Dh= 543μm, LHT = 60mm) made of transparent borosilicate glass is kept under constant wall heat flux conditions by means of a transparent metallic thin film deposit at the channel external wall as in Silvério and Moreira [1]. Heat transfer and pressure drop measurements are achieved by measuring the temperature and pressure at the channel inlet and outlet. Temperature is also measured along the channel outer wall. Experiments are carried with two different fluids, ethanol and methanol. Inlet liquid subcooling is of 297K, mass fluxes, G, up to 689kg.m-2.s-1 and imposed heat fluxes, q"s, up to 12.5W.cm-2 at ΔTsub from 0.8 to 50K. Synchronized high-speed visualization and microscope optics are used to determine dominant two-phase flow patterns and characterize hydrodynamic instabilities. Vapor qualities, χ, of -0.1 (indicating a subcooled liquid state) to 0.5 are under investigation. Semi-periodic variation of the flow patterns is noticeable for different flow conditions.

  5. Inertially-induced secondary flow in microchannels

    CERN Document Server

    Amini, Hamed; Di Carlo, Dino

    2011-01-01

    We report a novel technique to passively create strong secondary flows at moderate to high flow rates in microchannels, accurately control them and finally, due to their deterministic nature, program them into microfluidic platforms. Based on the flow conditions and due to the presence of the pillars in the channel, the flow streamlines will lose their fore-aft symmetry. As a result of this broken symmetry the fluid is pushed away from the pillar at the center of the channel (i.e. central z-plane). As the flow needs to maintain conservation of mass, the fluid will laterally travel in the opposite direction near the top and bottom walls. Therefore, a NET secondary flow will be created in the channel cross-section which is depicted in this video. The main platform is a simple straight channel with posts (i.e. cylindrical pillars - although other pillar cross-sections should also function) placed along the channel. Channel measures were 200 \\mum\\times50 \\mum, with pillars of 100 \\mum in diameter. Positioning the...

  6. Performance of Small Pore Microchannel Plates

    Science.gov (United States)

    Siegmund, O. H. W.; Gummin, M. A.; Ravinett, T.; Jelinsky, S. R.; Edgar, M.

    1995-01-01

    Small pore size microchannel plates (MCP's) are needed to satisfy the requirements for future high resolution small and large format detectors for astronomy. MCP's with pore sizes in the range 5 micron to 8 micron are now being manufactured, but they are of limited availability and are of small size. We have obtained sets of Galileo 8 micron and 6.5 micron MCP's, and Philips 6 micron and 7 micron pore MCP's, and compared them to our larger pore MCP Z stacks. We have tested back to back MCP stacks of four of these MCP's and achieved gains greater than 2 x 1O(exp 7) with pulse height distributions of less than 40% FWHM, and background rates of less than 0.3 events sec(exp -1) cm(exp -2). Local counting rates up to approx. 100 events/pore/sec have been attained with little drop of the MCP gain. The bare MCP quantum efficiencies are somewhat lower than those expected, however. Flat field images are characterized by an absence of MCP fixed pattern noise.

  7. Measuring the 3D motion of particles in microchannel acoustophoresis using astigmatism particle tracking velocimetry

    DEFF Research Database (Denmark)

    Augustsson, P.; Barnkob, Rune; Bruus, Henrik;

    2012-01-01

    We introduce full three-dimensional tracking of particles in an acoustophoresis microchannel using Astigmatism Particle Tracking Velocimetry (APTV) [1]. For the first time the interaction between acoustic streaming and the primary acoustic radiation force in microchannel acoustophoresis...

  8. Simple method for preparation of nanostructure on microchannel surface and its usage for enzyme-immobilization.

    Science.gov (United States)

    Miyazaki, Masaya; Kaneno, Jun; Uehara, Masato; Fujii, Masayuki; Shimizu, Hazime; Maeda, Hideaki

    2003-03-07

    We developed a novel preparation method of nanostructure on the microchannel surface formed by sol-gel like simple treatment with 3-aminopropyltriethoxysilane, which is suitable for a highly efficient enzyme-immobilized microchannel reactor.

  9. Monolithic Integration of GaN-based LEDs

    Energy Technology Data Exchange (ETDEWEB)

    Ao, Jin-Ping, E-mail: jpao@ee.tokushima-u.ac.jp [Institute of Technology and Science, University of Tokushima 2-1 Minami-Josanjima, Tokushima 770-8506 (Japan)

    2011-02-01

    The technology of monolithically integrated GaN-based light-emitting diodes (LEDs) is reported. First, the technology details to realize monolithic integration are described, including the circuit design for high-voltage and alternating current (AC) operation and the technologies for device isolation. The performances of the fabricated monolithic LED arrays are then demonstrated. A monolithic series array with totally 40 LEDs exhibited expected operation function under AC bias. The operation voltage of the array is 72 V when 20 LEDs were connected in series. Some modified circuit designs for high-voltage operation and other monolithic LED arrays are finally reviewed.

  10. Vapor bubble evolution on a heated surface containing open microchannels

    Science.gov (United States)

    Forster, Christopher J.; Glezer, Ari; Smith, Marc K.

    2011-11-01

    Power electronics require cooling technologies capable of high heat fluxes at or below the operating temperatures of these devices. Boiling heat transfer is an effective choice for such cooling, but it is limited by the critical heat flux (CHF), which is typically near 125 W/cm2 for pool boiling of water on a flat plate at standard pressure and gravity. One method of increasing CHF is to incorporate an array of microchannels into the heated surface. Microchannels have been experimentally shown to improve CHF, and the goal of this study is to determine the primary mechanisms associated with the microchannels that allow for the increased CHF. While the use of various microstructures is not new, the emphasis of previous work has been on heat transfer aspects, as opposed to the fluid dynamics inside and in the vicinity of the microchannels. This work considers the non-isothermal fluid motion during bubble growth and departure by varying channel geometry, spacing, and heat flux input using a level-set method including vaporization and condensation. These results and the study of the underlying mechanisms will aid in the design optimization of microchannel-based cooling devices. Supported by ONR.

  11. Thermal bonding of polyimide to form sealed microchannels

    Science.gov (United States)

    Mekaru, Harutaka

    2017-06-01

    Polyimide has high stability, so it is attractive for use in disposable microfluidic chips. Also, it has high resistance to soft X-ray irradiation. However, its high stability makes processing polyimide difficult. In particular, sealed microchannels are difficult to fabricate; additives are usually required. Here, a technique for sealing microchannels by thermal bonding using ordinary polyimide without any special functionalities is developed. First, as a guide to form sealed microchannels in polyimide microfluidic chips, optimum bonding conditions are determined by measuring bonding strength through tensile testing. Trench structures are formed by laser ablation on the surface of a polyimide substrate, and then the polyimide substrate is bonded thermally with a polyimide film under optimal bonding conditions. The water-tightness of the resulting chip is checked by feeding a liquid into the sealed microchannels. The bonding conditions obtained in the tensile test form sealed microchannels on the polyimide microfluidic chip. Using our technique for fabricating a polyimide chip, it will be possible to easily observe microstructures in a cell containing water in a soft X-ray microscope.

  12. Magnetic microparticle-polydimethylsiloxane composite for reversible microchannel bonding.

    Science.gov (United States)

    Tsao, Chia-Wen; Lee, Yueh-Pu

    2016-01-01

    In this study, an iron oxide magnetic microparticles and poly(dimethylsiloxane) (MMPs-PDMS) composite material was employed to demonstrate a simple high-strength reversible magnetic bonding method. This paper presents the casting of opaque-view (where optical inspection through the microchannels was impossible) and clear-view (where optical inspection through the microchannel was possible) MMPs-PDMS. The influence of the microchannel geometries on the casting of the opaque-view casting was limited, which is similar to standard PDMS casting. Clear-view casting performance was highly associated with the microchannel geometries. The effects of the microchannel layout and the gap between the PDMS cover layer and the micromold substrate were thoroughly investigated. Compared with the native PDMS bonding strength of 31 kPa, the MMPs-PDMS magnetic bonding experiments showed that the thin PDMS film with an MMPs-PDMS layer effectively reduced the surface roughness and enhanced MMPs-PDMS reversible magnetic bonding strength. A thin PDMS film-coated opaque-view MMPs-PDMS device exhibited the greatest bonding strength of 110 kPa, and a clear-view MMPs-PDMS device with a thin PDMS film attained a magnetic bonding strength of 81 kPa.

  13. Monolithic resonant optical reflector laser diodes

    Science.gov (United States)

    Hirata, T.; Suehiro, M.; Maeda, M.; Hihara, M.; Hosomatsu, H.

    1991-10-01

    The first monolithic resonant optical reflector laser diode that has a waveguide directional coupler and two DBR reflectors integrated by compositional disordering of quantum-well heterostructures is described. A linewidth of 440 kHz was obtained, and this value is expected to be greatly decreased by reducing the propagation loss in the integrated waveguide.

  14. Constant capacitance in nanopores of carbon monoliths.

    Science.gov (United States)

    García-Gómez, Alejandra; Moreno-Fernández, Gelines; Lobato, Belén; Centeno, Teresa A

    2015-06-28

    The results obtained for binder-free electrodes made of carbon monoliths with narrow micropore size distributions confirm that the specific capacitance in the electrolyte (C2H5)4NBF4/acetonitrile does not depend significantly on the micropore size and support the foregoing constant result of 0.094 ± 0.011 F m(-2).

  15. Nanoimprint lithography with a focused laser beam for the fabrication of nanopatterned microchannel molds.

    Science.gov (United States)

    Lim, Hyungjun; Ryu, Jihyeong; Kim, Geehong; Choi, Kee-Bong; Lee, Sunghwi; Lee, Jaejong

    2013-08-21

    We present a process based on nanoimprint lithography for the fabrication of a microchannel mold having nanopatterns formed at the bottoms of its microchannels. A focused laser beam selectively cures the resist in the micrometer scale during nanoimprint lithography. Nanopatterns within the microchannels may be used to control microfluidic behavior.

  16. NUMERICAL ANALYSIS OF GASEOUS FLOW IN MICRO-CHANNELS

    Institute of Scientific and Technical Information of China (English)

    Xu Jie; Gu Chuangang; Wang Tong

    2004-01-01

    The algorithm of gaseous flow in bi-dimensional micro-channels is set up and the corresponding program based on micro-flow theory is presented. Gaseous flow in micro-channels is numerically analyzed and the pressure drop along the duct as well as the velocity profile in the micro-channels is obtained. The numerical results agreed well with the experimental results in the references. Moreover, the effects of Kn, (σv and Re on the velocity profiles are analyzed. It is found that for Kn>0.001, with increasing Kn number, the slip velocity on the wall boundary increases; the tangential momentum coefficient (σv affects the slip velocity greatly. The slip velocity increases with decreasing (σv In the slip flow regime and for low Re numbers, the slip velocity is little influenced by the Re number.

  17. Detection of Aeromonas hydrophila Using Fiber Optic Microchannel Sensor

    Directory of Open Access Journals (Sweden)

    Samla Gauri

    2017-01-01

    Full Text Available This research focuses on the detection of Aeromonas hydrophila using fiber optic microchannel biosensor. Microchannel was fabricated by photolithography method. The fiber optic was chosen as signal transmitting medium and light absorption characteristic of different microorganisms was investigated for possible detection. Experimental results showed that Aeromonas hydrophila can be detected at the region of UV-Vis spectra between 352 nm and 354 nm which was comparable to measurement provided by UV spectrophotometer and also theoretical calculation by Beer-Lambert Absorption Law. The entire detection can be done in less than 10 minutes using a total volume of 3 μL only. This result promises good potential of this fiber optic microchannel sensor as a reliable, portable, and disposable sensor.

  18. Simulation of rarefied gas flow and heat transfer in microchannels

    Institute of Scientific and Technical Information of China (English)

    王娴; 王秋旺; 陶文铨; 郑平

    2002-01-01

    Analysis and simulation of rarefied nitrogen gas flow and heat transfer were performed with the Knusden number ranging from 0.05 to 1.0, using the direct simulation of Monte Carlo (DSMC) method. The influences of the Kn number and the aspect ratio on the gas temperature and wall heat flux in the microchannels were studied parametrically. The total and local heat fluxes of the microchannel walls varying with the channel inlet velocities were also investigated in detail. It was found that the Kn number and the aspect ratio greatly influence the heat transfer performance of microchannels, and both the channel inlet and outlet have higher heat fluxes while the heat flux in the middle part of channels is very low. It is also found that the inlet free stream flow velocity has small affect on the wall total heat flux while it changes the distribution of local heat flux.

  19. Expanded microchannel heat exchanger: design, fabrication and preliminary experimental test

    CERN Document Server

    Denkenberger, David C; Pearce, Joshua M; Zhai, John; 10.1177/0957650912442781

    2012-01-01

    This paper first reviews non-traditional heat exchanger geometry, laser welding, practical issues with microchannel heat exchangers, and high effectiveness heat exchangers. Existing microchannel heat exchangers have low material costs, but high manufacturing costs. This paper presents a new expanded microchannel heat exchanger design and accompanying continuous manufacturing technique for potential low-cost production. Polymer heat exchangers have the potential for high effectiveness. The paper discusses one possible joining method - a new type of laser welding named "forward conduction welding," used to fabricate the prototype. The expanded heat exchanger has the potential to have counter-flow, cross-flow, or parallel-flow configurations, be used for all types of fluids, and be made of polymers, metals, or polymer-ceramic precursors. The cost and ineffectiveness reduction may be an order of magnitude or more, saving a large fraction of primary energy. The measured effectiveness of the prototype with 28 micro...

  20. Fully integrated monolithic opoelectronic transducer for real.time protein and DNA detection

    DEFF Research Database (Denmark)

    Misiakos, Konstatinos; S. Petrou, Panagiota; E. Kakabakos, Sotirios

    2010-01-01

    scheme through a board-to-board receptacle was developed and combined with a portable customized readout and control instrument. Real-time detection of deleterious mutations in BRCA1 gene related to predisposition to hereditary breast/ovarian cancer was performed with the instrument developed using PCR......The development and testing of a portable bioanalytical device which was capable for real-time monitoring of binding assays was demonstrated. The device was based on arrays of nine optoelectronic transducers monolithically integrated on silicon chips. The optocouplers consisted of nine silicon...... products. Detection was based on waveguided photons elimination through interaction with fluorescently labeled PCR products. Detection of single biomolecular binding events was also demonstrated using nanoparticles as labels. In addition, label-free monitoring of bioreactions in real time was achieved...

  1. Enabling Microliquid Chromatography by Microbead Packing of Microchannels

    Science.gov (United States)

    Balvin, Manuel; Zheng, Yun

    2014-01-01

    The microbead packing is the critical element required in the success of on-chip microfabrication of critical microfluidic components for in-situ analysis and detection of chiral amino acids. In order for microliquid chromatography to occur, there must be a stationary phase medium within the microchannel that interacts with the analytes present within flowing fluid. The stationary phase media are the microbeads packed by the process discussed in this work. The purpose of the microliquid chromatography is to provide a lightweight, low-volume, and low-power element to separate amino acids and their chiral partners efficiently to understand better the origin of life. In order to densely pack microbeads into the microchannels, a liquid slurry of microbeads was created. Microbeads were extracted from a commercially available high-performance liquid chromatography column. The silica beads extracted were 5 microns in diameter, and had surface coating of phenyl-hexyl. These microbeads were mixed with a 200- proof ethanol solution to create a microbead slurry with the right viscosity for packing. A microfilter is placed at the outlet via of the microchannel and the slurry is injected, then withdrawn across a filter using modified syringes. After each injection, the channel is flushed with ethanol to enhance packing. This cycle is repeated numerous times to allow for a tightly packed channel of microbeads. Typical microbead packing occurs in the macroscale into tubes or channels by using highly pressurized systems. Moreover, these channels are typically long and straight without any turns or curves. On the other hand, this method of microbead packing is completed within a microchannel 75 micrometers in diameter. Moreover, the microbead packing is completed into a serpentine type microchannel, such that it maximizes microchannel length within a microchip. Doing so enhances the interactions of the analytes with the microbeads to separate efficiently amino acids and amino acid

  2. Micro-fabricated Silicon Devices for Advanced Thermal Management and Integration of Particle Tracking Detectors

    CERN Document Server

    Romagnoli, Giulia; Gambaro, Carla

    Since their first studies targeting the cooling of high-power computing chips, micro-channel devices are proven to provide a very efficient cooling system. In the last years micro-channel cooling has been successfully applied to the cooling of particle detectors at CERN. Thanks to their high thermal efficiency, they can guarantee a good heat sink for the cooling of silicon trackers, fundamental for the reduction of the radiation damage caused by the beam interactions. The radiation damage on the silicon detector is increasing with temperature and furthermore the detectors are producing heat that should be dissipated in the supporting structure. Micro-channels guarantee a distributed and uniform thermal exchange, thanks to the high flexibility of the micro-fabrication process that allows a large variety of channel designs. The thin nature of the micro-channels etched inside silicon wafers, is fulfilling the physics requirement of minimization of the material crossed by the particle beam. Furthermore micro-chan...

  3. FIBROUS MONOLITH WEAR RESISTANT COMPONENTS FOR THE MINING INDUSTRY

    Energy Technology Data Exchange (ETDEWEB)

    Mark J. Rigali

    2001-10-01

    Published mechanical and thermal properties data on a variety of materials was gathered, with focus on materials that have potential with respect to developing wear resistant and damage tolerant composite for mining industry applications. Preliminary core materials of interest include but are not limited to: Diamond, Tungsten Carbide and Cemented Tungsten Carbides, Carbides of Boron, Silicon, Titanium and Aluminum, Diboride of Titanium and Aluminum, Nitrides of Aluminum, Silicon, Titanium, and Boron, Aluminum Oxide, Tungsten, Titanium, Iron, Cobalt and Metal Alloys. Preliminary boundary materials of interest include but are not limited to: W metal, WC-Co, W-Co, WFeNi, and Mo metal and alloys. Several FM test coupons were fabricated with various compositions using the above listed materials. These coupons were consolidated to varying degrees by uniaxial hot pressing, then cut and ground to expose the FM cell structure. One promising system, WC-Co core and WFeNi boundary, was consolidated to 97% of theoretical density, and demonstrates excellent hardness. Data on standard mechanical tests was gathered, and tests will begin on the consolidated test coupons during the upcoming reporting period. The program statements of work for ACR Inc. and its subcontractors, as well as the final contract negotiations, were finalized during the current reporting period. The program start date was February 22nd, 2001. In addition to the current subcontractors, Kennametal Inc., a major manufacturer of cutting tools and wear resistant tooling for the mining industry, expressed considerable interest in ACR's Fibrous Monolith composites for both machine and mining applications. At the request of Kennametal, ARC Inc fabricated and delivered several Fibrous Monolith coupons and components for testing and evaluation in the mining and machine tool applications. Additional samples of Diamond/Tungsten Carbide-6%Cobalt Fibrous Monolith were fabricated and delivered for testing Kennametal

  4. Integrated optical and nuclear simulation of a monolithic LYSO:Ce based PET detector module

    Science.gov (United States)

    Játékos, B.; Patay, G.; Lőrincz, E.; Erdei, G.

    2017-05-01

    In the recent years new digital photon counter devices (also known as silicon photomultipliers, SiPMs) were designed and manufactured to be used specifically in positron emission tomography (PET) scanners. Finely pixelated SiPM arrays have opened new opportunities in PET detector development, such as the utilization of monolithic scintillator crystals. We worked out a simulation tool (SCOPE2) to assist the optimization and characterization of such PET detector modules. In the present paper we report the first application of SCOPE2 on the performance evaluation of a prototype PET detector module. The PET detector is based on monolithic LYSO:Ce scintillator crystal and a fully digital, silicon photon-counter, SPADnet-I. A new interface has been developed for SCOPE2 to access GATE simulation results. A combination of GATE and SCOPE2 was used to simulate excitation of the prototype PET detector with an electronically collimated γ -beam. Measurement results from the collimated γ-beam experiment were compared with the combined simulation. A good agreement was observed in the tendencies of total count spectrum and point of interaction distribution. We used the performance evaluation to understand and explain the measurement results in detail.

  5. DMAPS: a fully depleted monolithic active pixel sensor - analog performance characterization

    CERN Document Server

    Havránek, Miroslav; Krüger, Hans; Fu, Yunan; Germic, Leonard; Kishishita, Tetsuichi; Obermann, Theresa; Wermes, Norbert

    2014-01-01

    Monolithic Active Pixel Sensors (MAPS) have been developed since the late 1990s based on silicon substrates with a thin epitaxial layer (thickness of 10-15 $\\mu$m) in which charge is collected on an electrode, albeit by disordered and slow diffusion rather than by drift in a directed electric field. As a consequence, the signal is small ($\\approx$ 1000 e$^-$) and the radiation tolerance is much below the LHC requirements by factors of 100 to 1000. In this paper we present the development of a fully Depleted Monolithic Active Pixel Sensors (DMAPS) based on a high resistivity substrate allowing the creation of a fully depleted detection volume. This concept overcomes the inherent limitations of charge collection by diffusion in the standard MAPS designs. We present results from a test chip EPCB01 designed in a commercial 150 nm CMOS technology. The technology provides a thin (50 $\\mu$m) high resistivity n-type silicon substrate as well as an additional deep p-well which allows to integrate full CMOS circuitry i...

  6. DMAPS: a fully depleted monolithic active pixel sensor—analog performance characterization

    Science.gov (United States)

    Havránek, M.; Hemperek, T.; Krüger, H.; Fu, Y.; Germic, L.; Kishishita, T.; Marinas, C.; Obermann, T.; Wermes, N.

    2015-02-01

    Monolithic Active Pixel Sensors (MAPS) have been developed since the late 1990s based on silicon substrates with a thin epitaxial layer (thickness of 10-15 μm) in which charge is collected on an electrode, albeit by disordered and slow diffusion rather than by drift in a directed electric field. As a consequence, the signal of these conventional MAPS is small (≈1000 e-) and the radiation tolerance is limited. In this paper, the development of a fully Depleted Monolithic Active Pixel Sensors (DMAPS) based on a high resistivity substrate allowing the creation of a fully depleted detection volume is presented. This concept overcomes the inherent limitations of charge collection by diffusion in the standard MAPS designs. We present results from a prototype chip EPCB01 designed in a commercial 150 nm CMOS technology. The technology provides a thin (≈50 μm) high resistivity n-type silicon substrate as well as an additional deep p-well which allows to integrate full CMOS circuitry inside the pixel. Different matrix types with several variants of collection electrodes and pixel electronics have been implemented. Measurements of the analog performance of this first implementation of DMAPS pixels are presented.

  7. Design and Fabrication of a Monolithic Optoelectronic Integrated Circuit Chip Based on CMOS Compatible Technology

    Institute of Scientific and Technical Information of China (English)

    GUO Wei-Feng; ZHAO Yong; WANG Wan-Jun; SHAO Hai-Feng; YANG Jian-Yi; JIANG Xiao-Qing

    2012-01-01

    A monolithic optoelectronic integrated circuit chip on a silicon-on-insulator is designed and fabricated based on complementary metal oxide semiconductor compatible technology.The chip integrates an optical Mach-Zehnder modulator (MZM) and a CMOS driving circuit with the amplification function.Test results show that the extinction ratio of the MZM is close to 20dB and the small-signal gain of the CMOS driving circuit is about 26.9dB.A 50m V 10 MHz sine wave signal is amplified by the driving circuit,and then drives the MZM successfully.%A monolithic optoelectronic integrated circuit chip on a silicon-on-insulator is designed and fabricated based on complementary metal oxide semiconductor compatible technology. The chip integrates an optical Mach-Zehnder modulator (MZM) and a CMOS driving circuit with the amplification function. Test results show that the extinction ratio of the MZM is close to 20 dB and the small-signal gain of the CMOS driving circuit is about 26.9dB. A 50mV 10MHz sine wave signal is amplified by the driving circuit, and then drives the MZM successfully.

  8. Experimental study on silicon micro-heat pipe arrays

    Energy Technology Data Exchange (ETDEWEB)

    Launay, S.; Sartre, V.; Lallemand, M. [Institut National des Sciences Appliquees, Villeurbanne (France). Centre de Thermique

    2004-02-01

    In this study, micro-heat pipe arrays etched into silicon wafers have been investigated for electronic cooling purposes. Micro-heat pipes of triangular cross-section and with liquid arteries were fabricated by wet anisotropic etching with a KOH solution. The microchannels (230 {mu}m wide) are closed by molecular bonding of a plain wafer with the grooved one. A test bench was developed for the micro-heat pipe filling and the thermal characterisation. The temperature profile on the silicon surface is deduced from experimental measurements. The results show that with the artery micro-heat pipe array, filled with methanol, the effective thermal conductivity of the silicon wafer is significantly improved compared to massive silicon. (author)

  9. A monolithic integrated photonic microwave filter

    Science.gov (United States)

    Fandiño, Javier S.; Muñoz, Pascual; Doménech, David; Capmany, José

    2016-12-01

    Meeting the increasing demand for capacity in wireless networks requires the harnessing of higher regions in the radiofrequency spectrum, reducing cell size, as well as more compact, agile and power-efficient base stations that are capable of smoothly interfacing the radio and fibre segments. Fully functional microwave photonic chips are promising candidates in attempts to meet these goals. In recent years, many integrated microwave photonic chips have been reported in different technologies. To the best of our knowledge, none has monolithically integrated all the main active and passive optoelectronic components. Here, we report the first demonstration of a tunable microwave photonics filter that is monolithically integrated into an indium phosphide chip. The reconfigurable radiofrequency photonic filter includes all the necessary elements (for example, lasers, modulators and photodetectors), and its response can be tuned by means of control electric currents. This is an important step in demonstrating the feasibility of integrated and programmable microwave photonic processors.

  10. Macroporous Monolithic Polymers: Preparation and Applications

    Directory of Open Access Journals (Sweden)

    Cecilia Inés Alvarez Igarzabal

    2009-12-01

    Full Text Available In the last years, macroporous monolithic materials have been introduced as a new and useful generation of polymers used in different fields. These polymers may be prepared in a simple way from a homogenous mixture into a mold and contain large interconnected pores or channels allowing for high flow rates at moderate pressures. Due to their porous characteristics, they could be used in different processes, such as stationary phases for different types of chromatography, high-throughput bioreactors and in microfluidic chip applications. This review reports the contributions of several groups working in the preparation of different macroporous monoliths and their modification by immobilization of specific ligands on the products for specific purposes.

  11. Evaluation of an Infiltration Model with Microchannels

    Science.gov (United States)

    Garcia-Serrana, M.; Gulliver, J. S.; Nieber, J. L.

    2015-12-01

    This research goal is to develop and demonstrate the means by which roadside drainage ditches and filter strips can be assigned the appropriate volume reduction credits by infiltration. These vegetated surfaces convey stormwater, infiltrate runoff, and filter and/or settle solids, and are often placed along roads and other impermeable surfaces. Infiltration rates are typically calculated by assuming that water flows as sheet flow over the slope. However, for most intensities water flow occurs in narrow and shallow micro-channels and concentrates in depressions. This channelization reduces the fraction of the soil surface covered with the water coming from the road. The non-uniform distribution of water along a hillslope directly affects infiltration. First, laboratory and field experiments have been conducted to characterize the spatial pattern of flow for stormwater runoff entering onto the surface of a sloped surface in a drainage ditch. In the laboratory experiments different micro-topographies were tested over bare sandy loam soil: a smooth surface, and three and five parallel rills. All the surfaces experienced erosion; the initially smooth surface developed a system of channels over time that increased runoff generation. On average, the initially smooth surfaces infiltrated 10% more volume than the initially rilled surfaces. The field experiments were performed in the side slope of established roadside drainage ditches. Three rates of runoff from a road surface into the swale slope were tested, representing runoff from 1, 2, and 10-year storm events. The average percentage of input runoff water infiltrated in the 32 experiments was 67%, with a 21% standard deviation. Multiple measurements of saturated hydraulic conductivity were conducted to account for its spatial variability. Second, a rate-based coupled infiltration and overland model has been designed that calculates stormwater infiltration efficiency of swales. The Green-Ampt-Mein-Larson assumptions were

  12. Silicon microreactors for measurements of catalytic activity

    DEFF Research Database (Denmark)

    Henriksen, Toke Riishøj

    . The reactors consist of a microchannel system etched in an oxidized silicon chip and sealed with a glass lid using anodic bonding. The chip design relies on a gas flow through the channel system and is designed for reactions at pressures at the order of 1 bar. A high sensitivity is obtained by directing...... the entire gas flow through the reaction zone to a mass spectrometer, thus ensuring that nearly all reaction products are present in the analyzed gas flow. An experimental study has been carried out of the conditions for cavity collapse during anodic bonding of wide, shallow grooves etched in silicon...... has been employed as a test reaction. Using temperature ramping, it has been found that platinum catalysts with areas as small as 15μm2 are conveniently characterized with the device. A setup for locally cooled anodic bonding of microreactors is presented. The aim with this setup is to avoid catalyst...

  13. Update On Monolithic Fuel Fabrication Development

    Energy Technology Data Exchange (ETDEWEB)

    C. R Clark; J. M. Wight; G. C. Knighton; G. A. Moore; J. F. Jue

    2005-11-01

    Efforts to develop a viable monolithic research reactor fuel plate have continued at Idaho National Laboratory. These efforts have concentrated on both fabrication process refinement and scale-up to produce full sized fuel plates. Advancements have been made in the production of U-Mo foil including full sized foils. Progress has also been made in the friction stir welding and transient liquid phase bonding fabrication processes resulting in better bonding, more stable processes and the ability to fabricate larger fuel plates.

  14. FLUIDIZED BED STEAM REFORMER MONOLITH FORMATION

    Energy Technology Data Exchange (ETDEWEB)

    Jantzen, C

    2006-12-22

    Fluidized Bed Steam Reforming (FBSR) is being considered as an alternative technology for the immobilization of a wide variety of aqueous high sodium containing radioactive wastes at various DOE facilities in the United States. The addition of clay, charcoal, and a catalyst as co-reactants converts aqueous Low Activity Wastes (LAW) to a granular or ''mineralized'' waste form while converting organic components to CO{sub 2} and steam, and nitrate/nitrite components, if any, to N{sub 2}. The waste form produced is a multiphase mineral assemblage of Na-Al-Si (NAS) feldspathoid minerals with cage-like structures that atomically bond radionuclides like Tc-99 and anions such as SO{sub 4}, I, F, and Cl. The granular product has been shown to be as durable as LAW glass. Shallow land burial requires that the mineralized waste form be able to sustain the weight of soil overburden and potential intrusion by future generations. The strength requirement necessitates binding the granular product into a monolith. FBSR mineral products were formulated into a variety of monoliths including various cements, Ceramicrete, and hydroceramics. All but one of the nine monoliths tested met the <2g/m{sup 2} durability specification for Na and Re (simulant for Tc-99) when tested using the Product Consistency Test (PCT; ASTM C1285). Of the nine monoliths tested the cements produced with 80-87 wt% FBSR product, the Ceramicrete, and the hydroceramic produced with 83.3 wt% FBSR product, met the compressive strength and durability requirements for an LAW waste form.

  15. Monolithically integrated interferometer for optical displacement measurement

    Science.gov (United States)

    Hofstetter, Daniel; Zappe, Hans P.

    1996-01-01

    We discuss the fabrication of a monolithically integrated optical displacement sensors using III-V semiconductor technology. The device is configured as a Michelson interferometer and consists of a distributed Bragg reflector laser, a photodetector and waveguides forming a directional coupler. Using this interferometer, displacements in the 100 nm range could be measured at distances of up to 45 cm. We present fabrication, device results and characterization of the completed interferometer, problems, limitations and future applications will also be discussed.

  16. Distribution of Evaporating CO2 in Parallel Microchannels

    DEFF Research Database (Denmark)

    Brix, Wiebke; Elmegaard, Brian

    2008-01-01

    The impact on the heat exchanger performance due to maldistribution of evaporating CO2 in parallel channels is investigated numerically. A 1D steady state simulation model of a microchannel evaporator is built using correlations from the literature to calculate frictional pressure drop and heat...

  17. Conversion of Biomass Syngas to DME Using a Microchannel Reactor

    Energy Technology Data Exchange (ETDEWEB)

    Hu, Jianli; Wang, Yong; Cao, Chunshe; Elliott, Douglas C.; Stevens, Don J.; White, James F.

    2005-03-01

    The capability of a microchannel reactor for direct synthesis of dimethylether (DME) from biomass syngas was explored. The reactor was operated in conjunction with a hybrid catalyst system consisting of methanol synthesis and dehydration catalysts, and the influence of reaction parameters on syngas conversion was investigated. The activities of different dehydration catalysts were compared under DME synthesis conditions. Reaction temperature and pressure exhibited similar positive effects on DME formation. A catalytic stability test of the hybrid catalyst system was performed for 880 hours, during which CO conversion only decreased from 88% to 81%. In the microchannel reactor, the catalyst deactivation rate appeared to be much slower than in a tubular fixed-bed reactor tested for comparison. Test results also indicated that the dehydration reaction rate and the water depletion rate via a water-gas-shift reaction should be compatible in order to achieve high selectivity to DME. Using the microchannel reactor, it was possible to achieve a space time yield almost three times higher than commercially demonstrated performance results. A side-by-side comparison indicated that the heat removal capability of the microchannel reactor was at least six times greater than that of a commercial slurry reactor under similar reaction conditions.

  18. Laser Doppler velocimetry in Microchannels using integrated optical waveguides.

    NARCIS (Netherlands)

    Pandraud, G.; van den Berg, Albert; Semenov, S.N.

    2000-01-01

    The possibility of laser Doppler velocimetry (LDV) in microchannels, where particles are suspended in a liquid, and where oscillating or evanescent guided coherent light wave is present, is examined theoretically. The conditions for the observation of the transverse and longitudinal collective phore

  19. Microchannel apparatus and methods of conducting catalyzed oxidative dehydrogenation

    Science.gov (United States)

    Tonkovich, Anna Lee; Yang, Bin; Perry, Steven T.; Mazanec, Terry; Arora, Ravi; Daly, Francis P.; Long, Richard; Yuschak, Thomas D.; Neagle, Paul W.; Glass, Amanda

    2011-08-16

    Methods of oxidative dehydrogenation are described. Surprisingly, Pd and Au alloys of Pt have been discovered to be superior for oxidative dehydrogenation in microchannels. Methods of forming these catalysts via an electroless plating methodology are also described. An apparatus design that minimizes heat transfer to the apparatus' exterior is also described.

  20. Measurement of Threshold Pressure Gradient of Microchannels by Static Method

    Institute of Scientific and Technical Information of China (English)

    SONG Fu-Quan; JIANG Ren-Jie; BIAN Shu-Li

    2007-01-01

    The development of oil fields and laboratory experiment present the threshold pressure gradient (TPG) of liquid flow in low permeability porous media, which is called the micro-size effect in porous media. Some micro-size effects in micro-electro-mechanism systems (MEMS) are not always in agreement with each other. We propose an experiment setup to measure the TPG of microchannels by static method in the microchannels with the diameter ranging from 20-320 μm. The results present the existence of TPG in microchannel, and show an effect that the TPG of microchannel increases with decreasing hydrodynamic diameter. The relation between TPG and diameter is in agreement with single-log normalization. Additionally, the influence of errors in the experiment shows the data of experiment are valid. Finally, the mechanism of micro-size effects is discussed by revealing the facial force between liquid and solid and theory of boundary liquid, but the explanation is still not good, and needs further study.

  1. Lattice Boltzmann simulations of droplet formation during microchannel emulsification

    NARCIS (Netherlands)

    Zwan, van der E.A.; Sman, van der R.G.M.; Schroën, C.G.P.H.; Boom, R.M.

    2009-01-01

    In this study, we compared microchannel droplet formation in a microfluidics device with a two phase lattice Boltzmann simulation. The droplet formation was found to be qualitatively described, with a slightly smaller droplet in the simulation. This was due to the finite thickness of the interface i

  2. Microchannel Emulsification: From Computational Fluid Dynamics to Predictive Analytical Model

    NARCIS (Netherlands)

    Dijke, van K.C.; Schroën, C.G.P.H.; Boom, R.M.

    2008-01-01

    Emulsion droplet formation was investigated in terrace-based microchannel systems that generate droplets through spontaneous Laplace pressure driven snap-off. The droplet formation mechanism was investigated through high-speed imaging and computational fluid dynamics (CFD) simulation, and we found g

  3. Microchannels affect runoff and sediment yield from a shortgrass prairie

    Science.gov (United States)

    Runoff and sediment yield from rangelands are extremely important variables that affect productivity, but are difficult to quantify. Studies have been conducted to assess erosion on rangelands, but very little has been done to determine if microchannels (rills) affect runoff and sediment yield. Rain...

  4. CO2 dissolution in water using long serpentine microchannels

    OpenAIRE

    Cubaud, Thomas; Sauzade, Martin; SUN, RUOPENG

    2012-01-01

    The evolution of carbon dioxide bubbles dissolving in water is experimentally examined using long microchannels. We study the coupling between bubble hydrodynamics and dissolution in confined geometries. The gas impregnation process in liquid produces significant flow rearrangements. Depending on the initial volumetric liquid fraction, three operating regimes are identified, namely saturating, coalescing, and dissolving. The morphological and dynamical transition from segmented to dilute bubb...

  5. Concentration polarization, surface currents, and bulk advection in a microchannel

    DEFF Research Database (Denmark)

    Nielsen, Christoffer Peder; Bruus, Henrik

    2014-01-01

    We present a comprehensive analysis of salt transport and overlimiting currents in a microchannel during concentration polarization. We have carried out full numerical simulations of the coupled Poisson-Nernst-Planck-Stokes problem governing the transport and rationalized the behavior of the system...

  6. Performance evaluation of hybrid modified micro-channel solar cell ...

    African Journals Online (AJOL)

    user

    Keywords: Solar cell thermal tile, Micro-channel, Electrical efficiency, Thermal modeling. 1. ... than that of the PV modules is heated, while at the same time, the PV module ..... For a number of modified MCSCT tiles connected in series, the outlet ..... Group Technology, Neural Networks, and Non-traditional Optimization and.

  7. An overview of monolithic zirconia in dentistry

    Directory of Open Access Journals (Sweden)

    Özlem Malkondu

    2016-07-01

    Full Text Available Zirconia restorations have been used successfully for years in dentistry owing to their biocompatibility and good mechanical properties. Because of their lack of translucency, zirconia cores are generally veneered with porcelain, which makes restorations weaker due to failure of the adhesion between the two materials. In recent years, all-ceramic zirconia restorations have been introduced in the dental sector with the intent to solve this problem. Besides the elimination of chipping, the reduced occlusal space requirement seems to be a clear advantage of monolithic zirconia restorations. However, scientific evidence is needed to recommend this relatively new application for clinical use. This mini-review discusses the current scientific literature on monolithic zirconia restorations. The results of in vitro studies suggested that monolithic zirconia may be the best choice for posterior fixed partial dentures in the presence of high occlusal loads and minimal occlusal restoration space. The results should be supported with much more in vitro and particularly in vivo studies to obtain a final conclusion.

  8. Preparation of imprinted monolithic column under molecular crowding conditions

    Institute of Scientific and Technical Information of China (English)

    Xiao Xia Li; Xin Liu; Li Hong Bai; Hong Quan Duan; Yan Ping Huang; Zhao Sheng Liu

    2011-01-01

    Molecular crowding is a new concept to obtain molecularly imprinted polymers (MIPs) with greater capacity and selectivity. In this work, molecular crowding agent was firstly applied to the preparation of MIPs monolithic column. A new polymerization system based on molecular crowding surrounding was developed to prepare enrofloxacin-imprinted monolith, which was composed of polystyrene and tetrahydrofuran. The result showed that the monolithic MIPs under molecular crowding conditions presented good molecular recognition for enrofloxacin with an imprinting factor of 3.03.

  9. Design of monolithically integrated GeSi electro-absorption modulators and photodetectors on a SOI platform

    Science.gov (United States)

    Liu, Jifeng; Pan, Dong; Jongthammanurak, Samerkhae; Wada, Kazumi; Kimerling, Lionel C.; Michel, Jurgen

    2007-01-01

    We present a design of monolithically integrated GeSi electroabsorption modulators and photodetectors for electronic-photonic integrated circuits on a silicon-on-insulator (SOI) platform. The GeSi electroabsorption modulator is based on the Franz-Keldysh effect, and the GeSi composition is chosen for optimal performance around 1550 nm. The designed modulator device is butt-coupled to Si(core)/SiO2(cladding) high index contrast waveguides, and has a predicted 3 dB bandwidth of >50 GHz and an extinction ratio of 10 dB. The same device structure can also be used for a waveguide-coupled photodetector with a predicted responsivity of > 1 A/W and a 3 dB bandwidth of > 35 GHz. Use of the same GeSi composition and device structure allows efficient monolithic process integration of the modulators and the photodetectors on an SOI platform.

  10. MicroChannel Reactors for ISRU Applications Using Nanofabricated Catalysts

    Science.gov (United States)

    Carranza, Susana; Makel, Darby B.; Vander Wal, Randall L.; Berger, Gordon M.; Pushkarev, Vladimir V.

    2006-01-01

    With the new direction of NASA to emphasize the exploration of the Moon, Mars and beyond, quick development and demonstration of efficient systems for In-Situ Resources Utilization (ISRU) is more critical and timely than ever before. Affordable planning and execution of prolonged manned space missions depend upon the utilization of local resources and the waste products which are formed in manned spacecraft and surface bases. This paper presents current development of miniaturized chemical processing systems that combine microchannel reactor design with nanofabricated catalysts. Carbon nanotubes (CNT) are used to produce a nanostructure within microchannel reactors, as support for catalysts. By virtue of their nanoscale dimensions, nanotubes geometrically restrict the catalyst particle size that can be supported upon the tube walls. By confining catalyst particles to sizes smaller than the CNT diameter, a more uniform catalyst particle size distribution may be maintained. The high dispersion permitted by the vast surface area of the nanoscale material serves to retain the integrity of the catalyst by reducing sintering or coalescence. Additionally, catalytic efficiency increases with decreasing catalyst particle size (reflecting higher surface area per unit mass) while chemical reactivity frequently is enhanced at the nanoscale. Particularly significant is the catalyst exposure. Rather than being confined within a porous material or deposited upon a 2-d surface, the catalyst is fully exposed to the reactant gases by virtue of the nanofabricated support structure. The combination of microchannel technology with nanofabricated catalysts provides a synergistic effect, enhancing both technologies with the potential to produce much more efficient systems than either technology alone. The development of highly efficient microchannel reactors will be applicable to multiple ISRU programs. By selection of proper nanofabricated catalysts, the microchannel reactors can be

  11. Simulating characteristics of Si/Ge tandem monolithic solar cell with Si1-xGex buffer layer

    Directory of Open Access Journals (Sweden)

    Gnilenko A. B.

    2015-12-01

    Full Text Available In spite of many efforts to propose new semiconductor materials and sophisticated constructions of solar cells, crystalline silicone remains the main photovoltaic material widely used up to now. There are various methods to enhance the efficiency of silicone solar cells. One of them is to combine silicone with an additional semiconductor material with the different bandgap to form a tandem construction. For example, the germanium sub-cell used as the bottom cascade for the silicone sub-cell in the tandem monolithic solar cell makes it possible to utilize the "red" sub-band of solar spectra increasing overall solar cell efficiency. The problem of the 4.2% mismatch in lattice constant between Si and Ge can be resolved in such a case by the use of SiGe buffer layer. In the paper the results of the computer simulation for Si/Ge tandem monolithic solar cell with Si1-xGex buffer layer are presented. In the solar cell under consideration, the step graded Si1-xGex buffer layer is located between the top silicone and the bottom germanium cascades to reduce the threading dislocation density in mismatched materials. The cascades are commutated by the use of the germanium tunnel diode between the bottom sub-cell and the buffer layer. For the solar cell modeling, the physically-based device simulator ATLAS of Silvaco TCAD software is employed to predict the electrical behavior of the semiconductor structure and to provide a deep insight into the internal physical processes. The voltage-current characteristic, photovoltaic parameters and the distribution of basic physical values are obtained for the investigated tandem solar cell. The influence of layer thicknesses on the photovoltaic parameters is studied. The calculated efficiency of the tandem solar cell reaches 13% which is a quarter more than the efficiency of a simple silicone solar cell with the same constructive parameters and under the same illumination conditions.

  12. Monolithic Lumped Element Integrated Circuit (M2LEIC) Transistors.

    Science.gov (United States)

    INTEGRATED CIRCUITS, *MONOLITHIC STRUCTURES(ELECTRONICS), *TRANSISTORS, CHIPS(ELECTRONICS), FABRICATION, EPITAXIAL GROWTH, ULTRAHIGH FREQUENCY, POLYSILICONS, PHOTOLITHOGRAPHY, RADIOFREQUENCY POWER, IMPEDANCE MATCHING .

  13. Silicon nanophotonic devices for chip-scale optical communication applications [Invited].

    Science.gov (United States)

    Fainman, Y; Nezhad, M P; Tan, D T H; Ikeda, K; Bondarenko, O; Grieco, A

    2013-02-01

    This paper reviews recent work in the area of silicon photonic devices and circuits for monolithic and heterogeneous integration of circuits and systems on a chip. In this context, it presents fabrication results for producing low-loss silicon waveguides without etching. Resonators and add-drop distributed filters utilizing sidewall modulation fabricated in a single lithography and etching step are demonstrated. It also presents an optical pulse compressor that monolithically integrates self-phase modulation and anomalous dispersion compensation devices on a silicon chip. As an example of heterogeneous integration, we demonstrate vertical emitting metallo-dielectric nanolasers integrated onto a silicon platform. Future research directions toward large-scale photonic circuits and systems on a chip also are discussed.

  14. Microchannel emulsification study on formulation and stability characterization of monodisperse oil-in-water emulsions encapsulating quercetin.

    Science.gov (United States)

    Khalid, Nauman; Kobayashi, Isao; Neves, Marcos A; Uemura, Kunihiko; Nakajima, Mitsutoshi; Nabetani, Hiroshi

    2016-12-01

    The study used microchannel emulsification (MCE) to encapsulate quercetin in food grade oil-in-water (O/W) emulsions. A silicon microchannel plate (Model WMS 1-2) comprised of 10,300 discrete 10×104μm microslots was connected to a circular microhole with an inner diameter of 10μm. 1% (w/w) Tween 20 was used as optimized emulsifier in Milli-Q water, while 0.4mgml(-1) quercetin in different oils served as a dispersed phase. The MCE was carried by injecting the dispersed phase at 2mlh(-1). Successful emulsification was conducted below the critical dispersed phase flux, with a Sauter mean diameter of 29μm and relative span factor below 0.25. The O/W emulsions remained stable in terms of droplet coalescence at 4 and 25°C for 30days. The encapsulation efficiency of quercetin in the O/W emulsions was 80% at 4°C and 70% at 25°C during the evaluated storage period.

  15. Dark-Field Scanning Transmission Ion Microscopy via Detection of Forward-Scattered Helium Ions with a Microchannel Plate.

    Science.gov (United States)

    Woehl, Taylor J; White, Ryan M; Keller, Robert R

    2016-06-01

    A microchannel plate was used as an ion sensitive detector in a commercial helium ion microscope (HIM) for dark-field transmission imaging of nanomaterials, i.e. scanning transmission ion microscopy (STIM). In contrast to previous transmission HIM approaches that used secondary electron conversion holders, our new approach detects forward-scattered helium ions on a dedicated annular shaped ion sensitive detector. Minimum collection angles between 125 mrad and 325 mrad were obtained by varying the distance of the sample from the microchannel plate detector during imaging. Monte Carlo simulations were used to predict detector angular ranges at which dark-field images with atomic number contrast could be obtained. We demonstrate atomic number contrast imaging via scanning transmission ion imaging of silica-coated gold nanoparticles and magnetite nanoparticles. Although the resolution of STIM is known to be degraded by beam broadening in the substrate, we imaged magnetite nanoparticles with high contrast on a relatively thick silicon nitride substrate. We expect this new approach to annular dark-field STIM will open avenues for more quantitative ion imaging techniques and advance fundamental understanding of underlying ion scattering mechanisms leading to image formation.

  16. Evaluation of event position reconstruction in monolithic crystals that are optically coupled

    Science.gov (United States)

    Morrocchi, M.; Hunter, W. C. J.; Del Guerra, A.; Lewellen, T. K.; Kinahan, P. E.; MacDonald, L. R.; Bisogni, M. G.; Miyaoka, R. S.

    2016-12-01

    A PET detector featuring a pseudo-monolithic crystal is being developed as a more cost-effective alternative to a full monolithic crystal PET detector. This work evaluates different methods to localize the scintillation events in quartered monolithic crystals that are optically coupled. A semi-monolithic crystal assembly was formed using four 26  ×  26  ×  10 mm3 LYSO crystals optically coupled together using optical adhesive, to mimic a 52  ×  52  ×  10 mm3 monolithic crystal detector. The crystal assembly was coupled to a 64-channel multi-anode photomultiplier tube using silicon grease. The detector was calibrated using a 34  ×  34 scan grid. Events were first filtered and depth separated using a multi-Lorentzian fit to the collected light distribution. Next, three different techniques were explored to generate the look up tables for the event positioning. The first technique was ‘standard interpolation’ across the interface. The second technique was ‘central extrapolation’, where a bin was placed at the midpoint of the interface and events positioned within the interface region were discarded. The third technique used a ‘central overlap’ method where an extended region was extrapolated at each interface. Events were then positioned using least-squares minimization and maximum likelihood methods. The least-squares minimization applied to the look up table generated with the standard interpolation technique had the best full width at half maximum (FWHM) intrinsic spatial resolution and the lowest bias. However, there were discontinuities in the event positioning that would most likely lead to artifacts in the reconstructed image. The central extrapolation technique also had discontinuities and a 30% sensitivity loss near the crystal-crystal interfaces. The central overlap technique had slightly degraded performance metrics, but it still provided ~2.1 mm intrinsic spatial resolution at the crystal

  17. Selective oxidation of cyclohexene through gold functionalized silica monolith microreactors

    Science.gov (United States)

    Alotaibi, Mohammed T.; Taylor, Martin J.; Liu, Dan; Beaumont, Simon K.; Kyriakou, Georgios

    2016-04-01

    Two simple, reproducible methods of preparing evenly distributed Au nanoparticle containing mesoporous silica monoliths are investigated. These Au nanoparticle containing monoliths are subsequently investigated as flow reactors for the selective oxidation of cyclohexene. In the first strategy, the silica monolith was directly impregnated with Au nanoparticles during the formation of the monolith. The second approach was to pre-functionalize the monolith with thiol groups tethered within the silica mesostructure. These can act as evenly distributed anchors for the Au nanoparticles to be incorporated by flowing a Au nanoparticle solution through the thiol functionalized monolith. Both methods led to successfully achieving even distribution of Au nanoparticles along the length of the monolith as demonstrated by ICP-OES. However, the impregnation method led to strong agglomeration of the Au nanoparticles during subsequent heating steps while the thiol anchoring procedure maintained the nanoparticles in the range of 6.8 ± 1.4 nm. Both Au nanoparticle containing monoliths as well as samples with no Au incorporated were tested for the selective oxidation of cyclohexene under constant flow at 30 °C. The Au free materials were found to be catalytically inactive with Au being the minimum necessary requirement for the reaction to proceed. The impregnated Au-containing monolith was found to be less active than the thiol functionalized Au-containing material, attributable to the low metal surface area of the Au nanoparticles. The reaction on the thiol functionalized Au-containing monolith was found to depend strongly on the type of oxidant used: tert-butyl hydroperoxide (TBHP) was more active than H2O2, likely due to the thiol induced hydrophobicity in the monolith.

  18. Silicon spintronics.

    Science.gov (United States)

    Jansen, Ron

    2012-04-23

    Worldwide efforts are underway to integrate semiconductors and magnetic materials, aiming to create a revolutionary and energy-efficient information technology in which digital data are encoded in the spin of electrons. Implementing spin functionality in silicon, the mainstream semiconductor, is vital to establish a spin-based electronics with potential to change information technology beyond imagination. Can silicon spintronics live up to the expectation? Remarkable advances in the creation and control of spin polarization in silicon suggest so. Here, I review the key developments and achievements, and describe the building blocks of silicon spintronics. Unexpected and puzzling results are discussed, and open issues and challenges identified. More surprises lie ahead as silicon spintronics comes of age.

  19. Radiation hardness and timing studies of a monolithic TowerJazz pixel design for the new ATLAS Inner Tracker

    Science.gov (United States)

    Riegel, C.; Backhaus, M.; Van Hoorne, J. W.; Kugathasan, T.; Musa, L.; Pernegger, H.; Riedler, P.; Schaefer, D.; Snoeys, W.; Wagner, W.

    2017-01-01

    A part of the upcoming HL-LHC upgrade of the ATLAS Detector is the construction of a new Inner Tracker. This upgrade opens new possibilities, but also presents challenges in terms of occupancy and radiation tolerance. For the pixel detector inside the inner tracker, hybrid modules containing passive silicon sensors and connected readout chips are presently used, but require expensive assembly techniques like fine-pitch bump bonding. Silicon devices fabricated in standard commercial CMOS technologies, which include part or all of the readout chain, are also investigated offering a reduced cost as they are cheaper per unit area than traditional silicon detectors. If they contain the full readout chain, as for a fully monolithic approach, there is no need for the expensive flip-chip assembly, resulting in a further cost reduction and material savings. In the outer pixel layers of the ATLAS Inner Tracker, the pixel sensors must withstand non-ionising energy losses of up to 1015 n/cm2 and offer a timing resolution of 25 ns or less. This paper presents test results obtained on a monolithic test chip, the TowerJazz 180nm Investigator, towards these specifications. The presented program of radiation hardness and timing studies has been launched to investigate this technology's potential for the new ATLAS Inner Tracker.

  20. Selective ablation of photovoltaic materials with UV laser sources for monolithic interconnection of devices based on a-Si:H

    Energy Technology Data Exchange (ETDEWEB)

    Molpeceres, C. [Centro Laser UPM, Univ. Politecnica de Madrid, Crta. de Valencia Km 7.3, 28031 Madrid (Spain)], E-mail: carlos.molpeceres@upm.es; Lauzurica, S.; Garcia-Ballesteros, J.J.; Morales, M.; Guadano, G.; Ocana, J.L. [Centro Laser UPM, Univ. Politecnica de Madrid, Crta. de Valencia Km 7.3, 28031 Madrid (Spain); Fernandez, S.; Gandia, J.J. [Dept. de Energias Renovables, Energia Solar Fotovoltaica, CIEMAT, Avda, Complutense 22, 28040 Madrid (Spain); Villar, F.; Nos, O.; Bertomeu, J. [CeRMAE Dept. Fisica Aplicada i Optica, Universitat de Barcelona, Av. Diagonal 647, 08028 Barcelona (Spain)

    2009-03-15

    Lasers are essential tools for cell isolation and monolithic interconnection in thin-film-silicon photovoltaic technologies. Laser ablation of transparent conductive oxides (TCOs), amorphous silicon structures and back contact removal are standard processes in industry for monolithic device interconnection. However, material ablation with minimum debris and small heat affected zone is one of the main difficulty is to achieve, to reduce costs and to improve device efficiency. In this paper we present recent results in laser ablation of photovoltaic materials using excimer and UV wavelengths of diode-pumped solid-state (DPSS) laser sources. We discuss results concerning UV ablation of different TCO and thin-film silicon (a-Si:H and nc-Si:H), focussing our study on ablation threshold measurements and process-quality assessment using advanced optical microscopy techniques. In that way we show the advantages of using UV wavelengths for minimizing the characteristic material thermal affection of laser irradiation in the ns regime at higher wavelengths. Additionally we include preliminary results of selective ablation of film on film structures irradiating from the film side (direct writing configuration) including the problem of selective ablation of ZnO films on a-Si:H layers. In that way we demonstrate the potential use of UV wavelengths of fully commercial laser sources as an alternative to standard backscribing process in device fabrication.

  1. Energy Absorption of Monolithic and Fibre Reinforced Aluminium Cylinders

    NARCIS (Netherlands)

    De Kanter, J.L.C.G.

    2006-01-01

    Summary accompanying the thesis: Energy Absorption of Monolithic and Fibre Reinforced Aluminium Cylinders by Jens de Kanter This thesis presents the investigation of the crush behaviour of both monolithic aluminium cylinders and externally fibre reinforced aluminium cylinders. The research is based

  2. Time-based position estimation in monolithic scintillator detectors

    NARCIS (Netherlands)

    Tabacchini, V.; Borghi, G.; Schaart, D.R.

    2015-01-01

    Gamma-ray detectors based on bright monolithic scintillation crystals coupled to pixelated photodetectors are currently being considered for several applications in the medical imaging field. In a typical monolithic detector, both the light intensity and the time of arrival of the earliest

  3. Time-based position estimation in monolithic scintillator detectors

    NARCIS (Netherlands)

    Tabacchini, V.; Borghi, G.; Schaart, D.R.

    2015-01-01

    Gamma-ray detectors based on bright monolithic scintillation crystals coupled to pixelated photodetectors are currently being considered for several applications in the medical imaging field. In a typical monolithic detector, both the light intensity and the time of arrival of the earliest scintilla

  4. Time-based position estimation in monolithic scintillator detectors

    NARCIS (Netherlands)

    Tabacchini, V.; Borghi, G.; Schaart, D.R.

    2015-01-01

    Gamma-ray detectors based on bright monolithic scintillation crystals coupled to pixelated photodetectors are currently being considered for several applications in the medical imaging field. In a typical monolithic detector, both the light intensity and the time of arrival of the earliest scintilla

  5. A Monolithic Perovskite Structure for Use as a Magnetic Regenerator

    DEFF Research Database (Denmark)

    Pryds, Nini; Clemens, Frank; Menon, Mohan

    2011-01-01

    A La0.67Ca0.26Sr0.07Mn1.05O3 (LCSM) perovskite was prepared for the first time as a ceramic monolithic regenerator used in a regenerative magnetic refrigeration device. The parameters influencing the extrusion process and the performance of the regenerator, such as the nature of the monolith paste...

  6. Energy Absorption of Monolithic and Fibre Reinforced Aluminium Cylinders

    NARCIS (Netherlands)

    De Kanter, J.L.C.G.

    2006-01-01

    Summary accompanying the thesis: Energy Absorption of Monolithic and Fibre Reinforced Aluminium Cylinders by Jens de Kanter This thesis presents the investigation of the crush behaviour of both monolithic aluminium cylinders and externally fibre reinforced aluminium cylinders. The research is based

  7. Hydrogel coated monoliths for enzymatic hydrolysis of penicillin G

    NARCIS (Netherlands)

    De Lathouder, K.M.; Smeltink, M.W.; Straathof, A.J.J.; Paasman, M.A.; Van de Sandt, E.J.A.X.; Kapteijn, F.; Moulijn, J.A.

    2008-01-01

    The objective of this work was to develop a hydrogel-coated monolith for the entrapment of penicillin G acylase (E. coli, PGA). After screening of different hydrogels, chitosan was chosen as the carrier material for the preparation of monolithic biocatalysts. This protocol leads to active immobilize

  8. Monolithic aerogels with nanoporous crystalline phases

    Science.gov (United States)

    Daniel, Christophe; Guerra, Gaetano

    2015-05-01

    High porosity monolithic aerogels with nanoporous crystalline phases can be obtained from syndiotactic polystyrene and poly(2,6-dimethyl-1,4-phenylene)oxide thermoreversible gels by removing the solvent with supercritical CO2. The presence of crystalline nanopores in the aerogels based on these polymers allows a high uptake associated with a high selectivity of volatile organic compounds from vapor phase or aqueous solutions even at very low activities. The sorption and the fast kinetics make these materials particularly suitable as sorption medium to remove traces of pollutants from water and moist air.

  9. High gain micro-channel plate multipliers for particle tracking or single photo-electron counting

    Energy Technology Data Exchange (ETDEWEB)

    Oba, K.; Rehak, P.; Smith, S.D.

    1980-01-01

    Micro-channel plate multipliers have been used to detect the passage of relativistic charged particles. Measurements of the detection efficiency and pulse height response versus micro-channel plate gain are presented for one, two and three micro-channel plate arrays. Values describing temporal response and transit time jitter are also given. In a separate measurement, the response of a single micro-channel plate to individual slow electrons (less than or equal to 1 keV) was studied. By using a special technique output bunches as small as three electrons may be seen for low average micro-channel plate gain. The results of attempts to improve the micro-channel plate response are also presented.

  10. Numerical Simulation and Analysis of Gas-Liquid Flow in a T-Junction Microchannel

    Directory of Open Access Journals (Sweden)

    Hongtruong Pham

    2012-01-01

    Full Text Available Gas-liquid flow in microchannels is widely used in biomedicine, nanotech, sewage treatment, and so forth. Particularly, owing to the high qualities of the microbubbles and spheres produced in microchannels, it has a great potential to be used in ultrasound imaging and controlled drug release areas; therefore, gas-liquid flow in microchannels has been the focus in recent years. In this paper, numerical simulation of gas-liquid flows in a T-junction microchannel was carried out with computational fluid dynamics (CFD software FLUENT and the Volume-of-Fluid (VOF model. The distribution of velocity, pressure, and phase of fluid in the microchannel was obtained, the pressure distribution along the channel walls was analyzed in order to give a better understanding on the formation of microbubbles in the T-junction microchannel.

  11. Fabrication of the microchannel by metal-organic framework, copper benzenetricarboxylate.

    Science.gov (United States)

    Lim, Mikyung; Seo, You-Kyong; Park, Hyoun Hyang; Kim, Jin-Ha; Chang, Jong-San; Hwang, Young Kyu; Lee, Seung S

    2013-04-01

    We successfully fabricated the metal-organic framework (MOF), copper benzenetricarboxylate on a microchannel system, which was able to solve the problems created by increased heat dissipation in small electronic equipment. The microchannel system was designed to make an entrance part that can control the reaction temperature, which was predicted through a heat transfer analysis and the finite element method with COMSOL Multiphysics. Synthetic conditions, synthesis time, temperature and microchannel size were systematically tuned for the selective fabrication of copper benzenetricarboxylate on a microchannel surface. Scanning electron microscope (SEM) images, selected area electron diffraction (SAED) pattern and Fourier transform infrared (FT-IR) data clearly demonstrated that copper benzenetricarboxylate was strongly adhered to the bottom surfaces of the microchannels. Moreover, the synthesis of MOF in the microchannel system provided a much faster growth rate and better crystallinity compared to a conventional synthesis method.

  12. Spermatozoa scattering by a microchannel feature: an elastohydrodynamic model

    CERN Document Server

    Montenegro-Johnson, Thomas; Smith, David J

    2014-01-01

    Sperm traverse their microenvironment through viscous fluid by propagating flagellar waves; the waveform emerges as a consequence of elastic structure, internal active moments, and low Reynolds number fluid dynamics. Engineered microchannels have recently been proposed as a method of sorting and manipulating motile cells; the interaction of cells with these artificial environments therefore warrants investigation. A numerical method is presented for the geometrically nonlinear elastohydrodynamic interaction of active swimmers with domain features. This method is employed to examine hydrodynamic scattering by a model microchannel backstep feature. Scattering is shown to depend on backstep height and the relative strength of viscous and elastic forces in the flagellum. In a 'high viscosity' parameter regime corresponding to human sperm in cervical mucus analogue, this hydrodynamic contribution to scattering is comparable in magnitude to recent data on contact effects, being of the order of 5-10 degrees. Scatter...

  13. Bifurcation behaviors of catalytic combustion in a micro-channel

    Institute of Scientific and Technical Information of China (English)

    Wen Zeng; Maozhao Xie; Hongan Maa; Wei Xua

    2008-01-01

    Bifurcation analysis of ignition and extinction of catalytic combustion in a short micro-channel is carried out with the laminar flow model incorporated as the flow model. The square of transverse Thiele modulus and the realdence time are used as bifurcation parameters. The influences of different parameters on ignition and extinction behavior are investigated. It is shown that all these parameters have great effects on the bifurcation behaviors of ignition and extinction in the short micro-channel. The effects of flow models on bifurcation behaviors of combustion are also analyzed. The results show that in comparison with the fiat velocity profile model, for the case of the laminar flow model, the temperatures of ignition and extinction of combustion ate higher and the unsteady multiple solution region is larger.

  14. Interface oscillation of subcooled flow boiling in locally heated microchannels

    Science.gov (United States)

    Liu, J. T.; Peng, X. F.

    2009-02-01

    An investigation was conducted to understand flow boiling of subcooled de-ionized water in locally heated parallel microchannels. High-speed visualization technology was employed to visually observe the transient phase change process in an individual microchannel. Signal analysis method was employed in studying the interface movement and phase change process. The phase change at locally heated condition was different from those at entirely heated condition where elongated bubble(s) stayed quasi-stable for a long time without venting out. Diversified and intensive interface oscillation was observed occurring on both of the upstream and downstream bubble caps. Evaporation and condensation modes were characterized with distinguished oscillation frequencies. The film-driven oscillations of both evaporating and condensing interfaces generally operated at higher frequencies than the oscillations driven by nucleation or dropwise condensation.

  15. Tracking rare-isotope beams with microchannel plates

    CERN Document Server

    Rogers, A M; Lynch, W G; Tsang, M B; Lee, J; Bazin, D; Coupland, D; Henzl, V; Henzlova, D; Kilburn, M; Wallace, M S; Youngs, M; Delaunay, F; Famiano, M; Shapira, D; Jones, K L; Schmitt, K T; Sun, Z Y

    2013-01-01

    A system of two microchannel-plate detectors has been successfully implemented for tracking projectile-fragmentation beams. The detectors provide interaction positions, angles, and arrival times of ions at the reaction target. The current design is an adaptation of an assembly used for low-energy beams ($\\sim$1.4 MeV/nucleon). In order to improve resolution in tracking high-energy heavy-ion beams, the magnetic field strength between the secondary-electron accelerating foil and the microchannel plate had to be increased substantially. Results from an experiment using a 37-MeV/nucleon ${}^{56}$Ni beam show that the tracking system can achieve sub-nanosecond timing resolution and a position resolution of $\\sim$1 mm for beam intensities up to $5\\times10^{5}$ pps.

  16. Hex-square moire patterns in imagers using microchannel plates

    Science.gov (United States)

    Lawrence, George M.

    1989-01-01

    In electronic imaging detectors using microchannel plates, the mismatch between the pixels on a square mesh and the microchannels on a hexagonal mesh produces moire image defects. Theoretical statistical estimates of the sizes of the microposition offsets and the flat field intensity errors are calculated, showing the trade-off between resolution and position accuracy. A distinction is made between moments of spot images and moments of the single-pixel-response functions. As the resolution between the hex and square meshes is improved, the detector resolution is improved, but at the expense of an about 10 percent moire pattern. These moire patterns will not be properly corrected by dividing by the flat field image.

  17. Fabrication of microchannels in fused silica using femtosecond Bessel beams

    Energy Technology Data Exchange (ETDEWEB)

    Yashunin, D. A., E-mail: yashuninda@yandex.ru [Institute of Applied Physics of the Russian Academy of Sciences, 46 Ulyanov Str., Nizhny Novgorod 603950 (Russian Federation); Nizhny Novgorod State Technical University, 24 Minin St., Nizhny Novgorod 603950 (Russian Federation); Malkov, Yu. A. [Institute of Applied Physics of the Russian Academy of Sciences, 46 Ulyanov Str., Nizhny Novgorod 603950 (Russian Federation); Mochalov, L. A.; Stepanov, A. N. [Institute of Applied Physics of the Russian Academy of Sciences, 46 Ulyanov Str., Nizhny Novgorod 603950 (Russian Federation); Nizhny Novgorod State Technical University, 24 Minin St., Nizhny Novgorod 603950 (Russian Federation); Lobachevsky State University of Nizhny Novgorod, 23 Gagarin Ave., Nizhny Novgorod 603950 (Russian Federation)

    2015-09-07

    Extended birefringent waveguiding microchannels up to 15 mm long were created inside fused silica by single-pulse irradiation with femtosecond Bessel beams. The birefringent refractive index change of 2–4 × 10{sup −4} is attributed to residual mechanical stress. The microchannels were chemically etched in KOH solution to produce 15 mm long microcapillaries with smooth walls and a high aspect ratio of 1:250. Bessel beams provide higher speed of material processing compared to conventional multipulse femtosecond laser micromachining techniques and permit simple control of the optical axis direction of the birefringent waveguides, which is important for practical applications [Corrielli et al., “Rotated waveplates in integrated waveguide optics,” Nat. Commun. 5, 4249 (2014)].

  18. Neural signal registration and analysis of axons grown in microchannels

    Science.gov (United States)

    Pigareva, Y.; Malishev, E.; Gladkov, A.; Kolpakov, V.; Bukatin, A.; Mukhina, I.; Kazantsev, V.; Pimashkin, A.

    2016-08-01

    Registration of neuronal bioelectrical signals remains one of the main physical tools to study fundamental mechanisms of signal processing in the brain. Neurons generate spiking patterns which propagate through complex map of neural network connectivity. Extracellular recording of isolated axons grown in microchannels provides amplification of the signal for detailed study of spike propagation. In this study we used neuronal hippocampal cultures grown in microfluidic devices combined with microelectrode arrays to investigate a changes of electrical activity during neural network development. We found that after 5 days in vitro after culture plating the spiking activity appears first in microchannels and on the next 2-3 days appears on the electrodes of overall neural network. We conclude that such approach provides a convenient method to study neural signal processing and functional structure development on a single cell and network level of the neuronal culture.

  19. Influence of Transverse Magnetic Field on Microchannel Heat Sink Performance

    Directory of Open Access Journals (Sweden)

    K. Narrein

    2016-01-01

    Full Text Available The aim of the present numerical investigation is to analyze the effects of transverse magnetic field on heat transfer and fluid flow characteristics in a rectangular microchannel heat sink (MCHS. The effects of Hartmann number, channel aspect ratio, total channel height and total channel width on heat transfer and fluid flow characteristics are widely investigated. The governing equations for three-dimensional steady, laminar flow and conjugate heat transfer of a microchannel are solved using the finite volume method. The obtained results are discussed with various combinations of pertinent parameters involved in the study. The results reveal that magnetic field can enhance the thermal performance of the MCHS but it is accompanied with a slight increase in pressure drop.

  20. Single-phase convective heat transfer in microchannels

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    A comprehensive review is conducted on the investigations of the forced single-phase convective heat transfer in non-circular microchannels. The observations and results available in the open literature are inspected and compared for better understanding of the physical nature of the heat transfer performance and providing some lines of future research. There seems to be no unequivocal agreement in the understanding on the relative phenomena and the determination of the heat transfer coefficients in microchannels. The study on the interfacial phenomena and interaction at the interface will be the frontier in this area. Appropriate data reduction and the correlating parameters will be the cornerstone of comparability and evaluation for comprehensive investigations. The selection of correlating parameters will actually be the basis for the better understanding and description of new phenomena.

  1. Imaging MAMA detector systems. [Multi-Anode Microchannel Array

    Science.gov (United States)

    Slater, David C.; Timothy, J. G.; Morgan, Jeffrey S.; Kasle, David B.

    1990-01-01

    Imaging multianode microchannel array (MAMA) detector systems with 1024 x 1024 pixel formats have been produced for visible and UV wavelengths; the UV types employ 'solar blind' photocathodes whose detective quantum efficiencies are significantly higher than those of currently available CCDs operating at far-UV and EUV wavelengths. Attention is presently given to the configurations and performance capabilities of state-of-the-art MAMA detectors, with a view to the development requirements of the hybrid electronic circuits needed for forthcoming spacecraft-sensor applications. Gain, dark noise, uniformity, and dynamic range performance data are presented for the curved-channel 'chevron', 'Z-plate', and helical-channel high gain microchannel plate configurations that are currently under evaluation with MAMA detector systems.

  2. The microchannel flow model under shear stress and higher frequencies.

    Science.gov (United States)

    Parker, Kevin J

    2017-02-24

    The microchannel flow model provides a framework for considering the effect of the vascular bed on the time domain and frequency domain response of soft tissues. The derivation originates with a single small fluid filled vessel in an elastic medium under uniaxial compression. A fractal branching vasculature is also assumed to be present in the tissue under consideration. This short technical note considers two closely related issues. First, the response of the element under compression or shear as a function of the orientation of the fluid-filled vessel is considered. Second, the transition from quasistatic (Poiseuille's Law) to dynamic (Womersley equations) fluid flow is examined to better predict the evolution of behavior at higher frequencies. These considerations expand the conceptual framework of the microchannel flow model, particularly the range and limits of validity.

  3. The microchannel flow model under shear stress and higher frequencies

    Science.gov (United States)

    Parker, K. J.

    2017-04-01

    The microchannel flow model provides a framework for considering the effect of the vascular bed on the time domain and frequency domain response of soft tissues. The derivation originates with a single small fluid-filled vessel in an elastic medium under uniaxial compression. A fractal branching vasculature is also assumed to be present in the tissue under consideration. This note considers two closely related issues. First, the response of the element under compression or shear as a function of the orientation of the fluid-filled vessel is considered. Second, the transition from quasistatic (Poiseuille’s Law) to dynamic (Womersley equations) fluid flow is examined to better predict the evolution of behavior at higher frequencies. These considerations expand the conceptual framework of the microchannel flow model, particularly the range and limits of validity.

  4. Experimental comparison of mammalian and avian blood flow in microchannels

    Science.gov (United States)

    Fink, Kathryn; Liepmann, Dorian

    2015-11-01

    The non-Newtonian, shear rate dependent behavior of blood in microchannel fluid dynamics has been studied for nearly a century, with a significant focus on the characteristics of human blood. However, for over 200 years biologists have noted significant differences in red blood cell characteristics across vertebrate species, with particularly drastic differences in cell size and shape between mammals and non-mammalian classes. We present an experimental analysis of flow in long microchannels for several varieties of mammalian and avian blood, across a range of hematocrits, channel diameters, and flow rates. Correlation of shear rate and viscosity is compared to existing constitutive equations for human blood to further quantify the importance of red blood cell characteristics. Ongoing experimental results are made available in an online database for reference or collaboration. K.F. acknowledges funding from the ARCS Foundation and an NSF Graduate Research Fellowship through NSF Grant DGE 1106400.

  5. Low-dimensional modelling of flame dynamics in heated microchannels

    CERN Document Server

    Bianco, Federico; Legros, Guillaume

    2014-01-01

    This paper presents simulations of stoichiometric methane/air premixed flames into a microchannel at atmospheric pressure. These simulations result from numerical resolutions of reduced-order models. Indeed, combustion control into microchannels would be allowed by fast simulations that in turn enable real-time adjustments of the device's parameters. Former experimental studies reported the occurrence of a Flame Repetitive Extinction/Ignition (FREI) phenomenon provided that a temperature gradient is sustained at the channel's walls. Conducting unsteady one-dimensional simulations including complex chemistry, a late numerical study tried to explain the occurrence of this phenomenon. The present study therefore explores low-dimensional models that potentially reproduce the FREI phenomenon. Provided a calibration of some empirical constants, an unsteady two-dimensional model including one-step chemical reaction is shown to decently reproduce the FREI regime all along the range of mixture flow rates investigated ...

  6. Monolithically integrated self-rolled-up microtube-based vertical coupler for three-dimensional photonic integration

    Energy Technology Data Exchange (ETDEWEB)

    Yu, Xin; Arbabi, Ehsan; Goddard, Lynford L.; Li, Xiuling; Chen, Xiaogang, E-mail: oxgchen@illinois.edu [Department of Electrical and Computer Engineering, University of Illinois, Urbana, Illinois 61801 (United States)

    2015-07-20

    We demonstrate a self-rolled-up microtube-based vertical photonic coupler monolithically integrated on top of a ridge waveguide to achieve three-dimensional (3D) photonic integration. The fabrication process is fully compatible with standard planar silicon processing technology. Strong light coupling between the vertical coupler and the ridge waveguide was observed experimentally, which may provide an alternative route for 3D heterogeneous photonic integration. The highest extinction ratio observed in the transmission spectrum passing through the ridge waveguide was 23 dB.

  7. Tumbling of asymmetric microrods in a microchannel flow

    CERN Document Server

    Einarsson, J; Laas, A; Ankardal, S; Angilella, J R; Hanstorp, D; Mehlig, B

    2016-01-01

    We describe results of measurements of the orientational motion of glass microrods in a microchannel flow, following the orientational motion of particles with different shapes. We determine how the orientational dynamics depends on the shape of the particle and on its initial orientation. We find that the dynamics depends so sensitively on the degree to which axisymmetry is broken that it is difficult to find particles that are sufficiently axisymmetric so that they exhibit periodic tumbling ("Jeffery orbits").

  8. Measurement of the near-wall velocity profile for a nanofluid flow inside a microchannel

    Science.gov (United States)

    Kanjirakat, Anoop; Sadr, Reza

    2015-11-01

    Hydrodynamics and anomalous heat transfer enhancements have been reported in the past for colloidal suspensions of nano-sized particles dispersed in a fluid (nanofluids). However, such augmentations may manifest itself by study of fluid flow characteristics near in the wall region. Present experimental study reports near-wall velocity profile for nanofluids (silicon dioxide nanoparticles in water) measured inside a microchannel. An objective-based nano-Particle Image Velocimetry (nPIV) technique is used to measure fluid velocity within three visible depths, O(100nm), from the wall. The near-wall fluid velocity profile is estimated after implementing the required corrections for optical properties and effects caused by hindered Brownian motion, wall-particle interactions, and non-uniform exponential illumination on the measurement technique. The fluid velocities of nanofluids at each of the three visible depths are observed to be higher than that of the base fluid resulting in a higher shear rate in this region. The relative increase in shear rates for nanofluids is believed to be the result of the near-wall shear-induced particle migration along with the Brownian motion of the nanoparticles. This research is funded by NPRP grant # 08-574-2-239 from the Qatar National Research Fund (a member of Qatar Foundation).

  9. Experimental investigation of non-Newtonian/Newtonian liquid-liquid flow in microchannel

    Science.gov (United States)

    Roumpea, Eynagelia-Panagiota; Weheliye, Weheliye; Chinaud, Maxime; Angeli, Panagiota; Lyes Kahouadji Collaboration; Omar. K. Matar Collaboration

    2015-11-01

    Plug flow of an organic phase and an aqueous non-Newtonian solution was investigated experimentally in a quartz microchannel with I.D. 200 μm. The aqueous phase was a glycerol solution where 1000 and 2000 ppm of xanthan gum was added while the organic phase was silicon oil with 155 and 5 cSt viscosity. The two phases were brought together in a T-junction and their flowrates varied from 0.3 to 6 ml/hr. High speed imaging was used to study the characteristics of the plugs and the effect of the liquid properties on the flow patterns while a two-colour micro-PIV technique was used to investigate velocity profiles and circulation patterns within the plugs. The experimental results revealed that plug length was affected by both flowrate and viscosity. In all cases investigated, a film of the continuous phase always surrounded the plugs and its thickness was compared with existing literature models. Circulation patterns inside plugs were obtained by subtracting the plug velocity and found to be depended on the plug length and the amount of xanthan gum in the aqueous phase. Finally, the dimensionless circulation time was calculated and plotted as a function of the plug length. Department of Chemical Engineering South Kensington Campus Imperial College London SW7 2AZ.

  10. Progress towards a 256 channel multi-anode microchannel plate photomultiplier system with picosecond timing.

    Science.gov (United States)

    Lapington, J S; Ashton, T J R; Ross, D; Conneely, T

    2012-12-11

    Despite the rapid advances in solid state technologies such as the silicon photomultiplier (SiPM), microchannel plate (MCP) photomultipliers still offer a proven and practical technological solution for high channel count pixellated photon-counting systems with very high time resolution. We describe progress towards a 256 channel optical photon-counting system using CERN-developed NINO and HTDC ASICs, and designed primarily for time resolved spectroscopy in life science applications. Having previously built and demonstrated a 18 mm diameter prototype tube with an 8×8 channel readout configuration and <43 ps rms single photon timing resolution, we are currently developing a 40 mm device with a 32×32 channel readout. Initially this will be populated with a 256 channel electronics system comprising four sets of modular 64 channel preamplifier/discriminator, and time-to-digital converter units, arranged in a compact three dimensional configuration. We describe the detector and electronics design and operation, and present performance measurements from the 256 channel development system. We discuss enhancements to the system including higher channel count and the use of application specific on-board signal processing capabilities.

  11. Effect of shear-thinning behaviour on liquid-liquid plug flow in microchannels

    Science.gov (United States)

    Roumpea, Evangelia; Chinaud, Maxime; Weheliye, Weheliye Hashi; Angeli, Panagiota; Kahouadji, Lyes; Matar, Omar K.

    2016-11-01

    The present work investigates the dynamics of plug formation of shear-thinning solutions in a 200 μm microchannel using a two-colour micro-PIV system. Measurements, including phase-averaged velocity fields, have been conducted both at the T-junction inlet and the main channel to enhance understanding of non-Newtonian liquid-liquid flows. Two aqueous glycerol solutions containing xanthan gum are used as the non-Newtonian fluids while 5 cSt silicone oil is the Newtonian phase. The current experimental results revealed a pronounced impact of the xanthan gum (shear-thinning behaviour) on the flow pattern transition boundaries, and enhance the fluid flowrates where plug flow occurred. The addition of polymer resulted also in different hydrodynamic characteristics such as a bullet-shaped plug and an increased film thickness between the plug and the wall. In the present work, the technique allows to capture the velocity field of both phases simultaneously. Experimental results are compared with the numerical simulations provided by the code BLUE. Project funded under the UK Engineering and Physical Sciences Research Council (EPSRC) Programme Grant MEMPHIS.

  12. Analysing Gas-Liquid Flow in PEM Electrolyser Micro-Channels (Abstract)

    DEFF Research Database (Denmark)

    Lafmejani, Saeed Sadeghi; Olesen, Anders Christian; Kær, Søren Knudsen

    2016-01-01

    and are fairly expensive. One means of increasing the hydrogen yield to cost ratio of such systems, is to increase the operating current density. However, at high current densities, management of heat transfer and fluid flow in the anode GDL and channel becomes crucial. This entails that further understanding...... of the gas-liquid flow in both the porous media and the channel is necessary for insuring proper oxygen, water and heat management of the electrolysis cell. In this work, the vertical upward gas-liquid flow pattern in a 0.5×1×94 mm micro-channel is both numerically and experimentally analysed. A sheet...... the transparent cell is made which consists of a channel for the inlet air and a channel for the water-bubble flow. The transparent material is Plexiglas that is sealed with a sheet of silicon. The conventional co-current gas-liquid two-phase flow patterns, such as bubbly flow, slug flow and annular flow...

  13. Nanosecond Gating Properties Of Proximity-Focused Microchannel-Plate Image Intensifiers

    Science.gov (United States)

    King, N. S.; Yates, G. J.; Jaramillo, S. A.; Ogle, J. W.; Detch, J. L.

    1981-12-01

    Some fundamental properties of 18-mm-diam gated proximity-focussed microchannel-plate (MCP) image intensifiers used as fast image shutters in the 1 to 10 ns range have been identified and studied. Light pulses (≍ 5-ps-wide) from a modelocked dye laser optically sample the gated MCP. Shuttering is achieved by applying a forward-biasing electrical gate pulse to the quiescently reverse-biased photocathode-MCP interface. Variable delay (≍ 30-ps jitter) between the gate pulse and the laser pulse permit tracing the MCP's optical response. Gating speeds, turn-on and turn-off patterns, the asymmetric spatial dependence of the MCP optical response, and resolution effects as functions of gate pulse width and photocathode-MCP bias have been characterized. Shutter times of >= 750 ps and <= 5 1p/mm resolution with the MCP fully on were observed. Variations in the intensity profiles of the phosphorl.s spatial response for uniform photocathode illumination are measured with a calibrated silicon-intensified-target (SIT) focus projection, scan (FPS) television camera and a high-speed video digitizer while photomultipliers (PMTs) monitor the laser pulse and the phosphor's spatially integrated output intensities. The characterization system, gating and biasing circuits, and experimental results will be presented.

  14. Mid-infrared nonlinear silicon photonics

    Science.gov (United States)

    Liu, Xiaoping; Kuyken, Bart; Green, William M. J.; Osgood, Richard M.; Baets, Roel; Roelkens, Gunther

    2014-03-01

    Recently there has been a growing interest in mid-infrared (mid-IR) photonic technology with a wavelength of operation approximately from 2-14 μm. Among several established mid-IR photonic platforms, silicon nanophotonic platform could potentially offer ultra-compact, and monolithically integrated mid-IR photonic devices and device arrays, which could have board impact in the mid-IR technology, such as molecular spectroscopy, and imaging. At room temperature, silicon has a bandgap ~ 1.12 eV resulting in vanishing two-photon absorption (TPA) for mid-IR wavelengths beyond 2.2 μm, which, coupled with silicon's large nonlinear index of refraction and its strong waveguide optical confinement, enables efficient nonlinear processes in the mid-IR. By taking advantage of these nonlinear processes and judicious dispersion engineering in silicon waveguides, we have recently demonstrated a handful of silicon mid-IR nonlinear components, including optical parametric amplifiers (OPA), broadband sources, and a wavelength translator. Silicon nanophotonic waveguide's anomalous dispersion design, providing four-wave-mixing (FWM) phase-matching, has enabled the first demonstration of silicon mid-IR optical parametric amplifier (OPA) with a net off-chip gain exceeding 13 dB. In addition, reduction of propagation losses and balanced second and fourth order waveguide dispersion design led to an OPA with an extremely broadband gain spectrum from 1.9-2.5 μm and >50 dB parametric gain, upon which several novel silicon mid-IR light sources were built, including a mid-IR optical parametric oscillator, and a supercontinuum source. Finally, a mid-IR wavelength translation device, capable of translating signals near 2.4 μm to the telecom-band near 1.6 μm with simultaneous 19 dB gain, was demonstrated.

  15. Dynamics of rigid microparticles at the interface of co-flowing immiscible liquids in a microchannel.

    Science.gov (United States)

    Jayaprakash, K S; Banerjee, U; Sen, A K

    2017-05-01

    We report the dynamical migration behavior of rigid polystyrene microparticles at an interface of co-flowing streams of primary CP1 (aqueous) and secondary CP2 (oils) immiscible phases at low Reynolds numbers (Re) in a microchannel. The microparticles initially suspended in the CP1 either continue to flow in the bulk CP1 or migrate across the interface into CP2, when the stream width of the CP1 approaches the diameter of the microparticles. Experiments were performed with different secondary phases and it is found that the migration criterion depends on the sign of the spreading parameter S and the presence of surfactant at the interface. To substantiate the migration criterion, experiments were also carried out by suspending the microparticles in CP2 (oil phase). Our study reveals that in case of aqueous-silicone oil combination, the microparticles get attached to the interface since S90°. For complete detachment of microparticles from the interface into the secondary phase, additional energy ΔG is needed. We discuss the role of interfacial perturbation, which causes detachment of microparticles from the interface. In case of mineral and olive oils, the surfactants present at the interface prevents attachment of the microparticles to the interface due to the repulsive disjoining pressure. Finally, using a aqueous-silicone oil system, we demonstrate size based sorting of microparticles of size 25μm and 15μm respectively from that of 15μm and 10μm and study the variation of separation efficiency η with the ratio of the width of the aqueous stream to the diameter of the microparticles ρ.

  16. A heat transfer model for slug flow boiling within microchannels

    Science.gov (United States)

    Magnini, Mirco; Thome, John

    2016-11-01

    We propose a novel physics-based model for the fluid mechanics and heat transfer associated with slug flow boiling in horizontal circular microchannels, to update the widely used three-zone model for the design of multi-microchannel evaporators. The flow is modelled as the cyclic passage of a liquid slug, an elongated bubble which traps a thin liquid film against the channel wall, and a dry vapor plug. The capillary flow theory, extended to incorporate evaporation effects, is applied to estimate the bubble velocity along the channel. A liquid film thickness prediction method considering bubble proximity effects, which may limit the radial extension of the film, is included. Theoretical heat transfer models accounting for the thermal inertia of the liquid film and for the recirculating flow within the liquid slug are utilized. The heat transfer model is compared to experimental data taken from three independent studies: 833 slug flow boiling data points covering R134a, R245fa and R236fa and channel diameters from 0.4 mm to 1 mm. The new model predicts more than 80% of the database to within +/- 30 % and it represents an important step toward a complete physics-based modelling of bubble dynamics and heat transfer within microchannels under evaporating flow conditions.

  17. Design of microchannels for cryostabilization of high temperature superconducting magnets

    Science.gov (United States)

    Cha, Y. S.; Hull, J. R.; Niemann, R. C.

    Microchannel cooling using subcooled liquid nitrogen is proposed to cryogenically stabilize high-temperature superconducting magnets. Various design constraints and parameters are identified and summarized. A graphical method is proposed for the design of microchannel systems. This graphical method helps to reduce the amount of work towards achieving optimum design for a specific application because there are a large number of parameters involved in the design of a microchannel system. The proposed graphical method are illustrated by three examples. The results show that a design window may appear for a given application. Any point within this window is an acceptable design. Another advantage of the graphical method is that, by selecting a design point, the design margin against various design contrains can be easily identified. Any two of the design variables can be selected as the independent variables. The choice depends on specific application and, to a certain extent, on individual preference. The three examples revealed that, for high current density applications, the most scattering constraints are the coolant temperature rise and the fin tip temperatures provided that a moderate pressure drop can be tolerated.

  18. Peroxide dental bleaching via laser microchannels and tooth color measurements

    Science.gov (United States)

    Altshuler, Gregory; Belikov, Andrey; Skrypnik, Alexei; Feldchtein, Felix; Pushkareva, Alexandra; Shatilova, Ksenia; Cernavin, Igor; Tuchin, Valery

    2016-12-01

    The aim of this study was to use microchannels drilled by an Er:YAG laser into a human tooth through the enamel into the dentin for direct injection of hydrogen peroxide (HP) to produce a minimally invasive, rapid, tooth bleaching effect. The experiments were conducted in vitro. Five microchannels with a diameter of ˜200 μm and a depth of ˜2 mm were drilled through the palatal side of a human tooth crown using the microbeam of an Er:YAG-laser with a wavelength of 2.94 μm. After injection of an aqueous solution of 31%-HP through the microchannels, the tooth color was evaluated using a VITA shade guide and International Commission on Illumination L*ab color parameters. A tooth model used for the evaluation of the distribution of HP concentration was created and the amount of HP which can be injected into tooth dentin to bleach it safely was estimated. Injection of 1.5±0.1 mm3 of 31%-HP into the tooth led to noticeable bleaching within 3 h and significant improvement of tooth color within 24 h.

  19. Autothermal hydrogen generation from methanol in a ceramic microchannel network

    Science.gov (United States)

    Moreno, Angela M.; Wilhite, Benjamin A.

    In this paper, the authors present the first demonstration of a new class of integrated ceramic microchannel reactors for all-in-one reforming of hydrocarbon fuels. The reactor concept employs precision-machined metal distributors capable of realizing complex flow distribution patterns with extruded ceramic microchannel networks for cost-effective thermal integration of multiple chemical processes. The presently reported reactor is comprised of five methanol steam reforming channels packed with CuO/γ-Al 2O 3, interspersed with four methanol combustion channels washcoated with Pt/γ-Al 2O 3, for autothermal hydrogen production (i.e., without external heating). Results demonstrate the capability of this new device for integrating combustion and steam reforming of methanol for autothermal production of hydrogen, owing to the axially self-insulating nature of distributor-packaged ceramic microchannels. In the absence of any external insulation, stable reforming of methanol to hydrogen at conversions >90% and hydrogen yields >70% was achieved at a maximum reactor temperature of 400 °C, while simultaneously maintaining a packaging temperature <50 °C.

  20. Ceramic Microchannel Development for Compact Fuel Processors of Hydrocarbon Fuels

    Science.gov (United States)

    Bae, J.-M.; Ahmed, S.; Kumar, R.; Doss, E.

    Fuel processing is a bridging technology for faster commercialization of fuel cell system under lack of hydrogen infrastructures. Argonne national laboratory has been developing fuel processing technologies for fuel cell based electric power. We have reported the development of novel catalysts that are active and selective for hydrocarbon reforming reactions. It has been realized, however, that with pellet or conventional honeycomb catalysts, the reforming process is mass transport limited. This paper reports the development of catalyst structures with microchannels that are able to reduce the diffusion resistance and thereby achieve the same production rate within a smaller reactor bed. These microchannel reforming catalysts were prepared and tested with natural gas and gasoline-type fuels in a microreactor (1-cm dia.) at space velocities of up to 250,000 per hour. These catalysts have also been used in engineering-scale reactors (10 kWe, 7-cm dia.) with similar product qualities. Compared to pellet catalysts, the microchannel catalysts enable a nearly 5-fold reduction in catalyst weight and volume.

  1. Buckling delamination induced microchannel: Flow regulation in microfluidic devices

    Science.gov (United States)

    Kang, Jingtian; Wang, Changguo; Xue, Zhiming; Liu, Mengxiong; Tan, Huifeng

    2016-09-01

    The buckling delamination induced microchannel is employed to regulate fluid flow as a microvalve which can be utilized in microfluidic devices. This microvalve consists of a soft substrate and a stiff thin film, between which there is a pre-set small imperfection. Two critical strain values, namely, on-off strain and failure strain, have been proposed to determine the working strain interval using analytical predictions. Within this interval, the cross-sectional area of the microchannel can be controlled and predicted by different compressive strains of the film/substrate system. The fluid flow rate within this microchannel can be then estimated by both analytical and numerical simulations and adjusted to satisfy different values by alternating the compressive strain. In addition, a demonstrative experiment has been taken to verify the feasibility of this approach. This flexible microvalve has potential in the application where the use of traditional rigid microvalves is improper in flexible microfluidic devices. The method and approach of this paper can provide a general guide for flow rate control in microfluidic devices.

  2. Modulated iontophoretic delivery of small and large molecules through microchannels.

    Science.gov (United States)

    Kumar, Vijay; Banga, Ajay K

    2012-09-15

    The objective of this work was to modulate transdermal drug delivery by iontophoresis though skin microchannels created by microneedles. Calcein and human growth hormone were used as a model small and large molecule, respectively. In vitro permeation studies were performed on porcine ear skin under three different settings: (a) modulated iontophoresis alone, (b) pretreatment with microneedles and (c) combination of microneedles pretreatment and modulated iontophoresis. For modulated iontophoresis, 0.5 mA/cm(2) current was applied for 1h each at 2nd and 6th hour of the study. Methylene blue staining, calcein imaging and pore permeability index suggested maltose microneedles created uniform microchannels in skin. Application of iontophoresis provided two peaks in flux of 1.04 μg/(cm(2)h) at 4th hour and 2.09 μg/(cm(2)h) at 8th hour of study for calcein. These peaks in flux were significant higher when skin was pretreated with microneedles (piontophoresis. This combination also provided significant increase in cumulative amount of calcein and human growth hormone delivered as compared to microneedles or iontophoresis alone (piontophoresis can be used to modulate drug delivery across skin microchannels created by microneedles.

  3. Handcrafted multilayer PDMS microchannel scaffolds for peripheral nerve regeneration.

    Science.gov (United States)

    Hossain, Ridwan; Kim, Bongkyun; Pankratz, Rachel; Ajam, Ali; Park, Sungreol; Biswal, Sibani L; Choi, Yoonsu

    2015-12-01

    Injuries that result in the loss of limb functionality may be caused by the severing of the peripheral nerves within the affected limb. Several bioengineered peripheral nerve scaffolds have been developed in order to provide the physical support and topographical guidance necessary for the naturally disorganized axon outgrowth to reattach to distal nerve stumps as an alternative to other procedures, like nerve grafting. PDMS has been chosen for the base material of the scaffolds due to its biocompatibility, flexibility, transparency, and well-developed fabrication techniques. The process of observing the axon outgrowth across the nerve gaps with PDMS scaffolds has been challenging due to the limited number and fineness of longitudinal sections that can be extracted from harvested nerve tissue samples after implantation. To address this, multilayer microchannel scaffolds were developed with the object of providing more refined longitudinal observation of axon outgrowth by longitudinally 'sectioning' the device during fabrication, removing the need for much of the sample preparation process. This device was then implanted into the sciatic nerves of Lewis rats, and then harvested after two and four weeks to analyze the difference in nerve regeneration between two different time periods. The present layer by layer structure, which is separable after nerve regeneration and is treated as an individual layer during the histology process, provides the details of biological events during axonal regeneration. Confocal microscopic imaging showed the details of peripheral nerve regeneration including nerve branches and growth cones observable from within the microchannels of the multilayer PDMS microchannel scaffolds.

  4. Microplasma patterning of bonded microchannels using high-precision "injected" electrodes.

    Science.gov (United States)

    Priest, Craig; Gruner, Philipp J; Szili, Endre J; Al-Bataineh, Sameer A; Bradley, James W; Ralston, John; Steele, David A; Short, Robert D

    2011-02-07

    A rapid, high-precision method for localised plasma-treatment of bonded PDMS microchannels is demonstrated. Patterned electrodes were prepared by injection of molten gallium into preformed microchannel guides. The electrode guides were prepared without any additional fabrication steps compared to conventional microchannel fabrication. Alignment of the "injected" electrodes is precisely controlled by the photomask design, rather than positioning accuracy of alignment tools. Surface modification is detected using a fluorescent dye (Rhodamine B), revealing a well-defined micropattern with regions less than 100 µm along the length of the microchannel.

  5. Integrated microchannel cooling in a three dimensional integrated circuit: A thermal management

    Directory of Open Access Journals (Sweden)

    Wang Kang-Jia

    2016-01-01

    Full Text Available Microchannel cooling is a promising technology for solving the three-dimensional integrated circuit thermal problems. However, the relationship between the microchannel cooling parameters and thermal behavior of the three dimensional integrated circuit is complex and difficult to understand. In this paper, we perform a detailed evaluation of the influence of the microchannel structure and the parameters of the cooling liquid on steady-state temperature profiles. The results presented in this paper are expected to aid in the development of thermal design guidelines for three dimensional integrated circuit with microchannel cooling.

  6. Single microchannel high-temperature fiber sensor by femtosecond laser-induced water breakdown.

    Science.gov (United States)

    Liu, Yi; Qu, Shiliang; Li, Yan

    2013-02-01

    Single microchannel high-temperature fiber sensors were fabricated by drilling a microchannel across the fiber core near the end of the common single-mode fiber using femtosecond laser-induced water breakdown. Then the microchannel was annealed by the arc discharge to smooth its inwall. The two sides of microchannel and the end surface of the fiber constitute three reflective mirrors, which form a three-wave Fabry-Pérot interferometer (FPI). The fabricated FPI can be used as a high-temperature sensor in harsh environments due to its large temperature range (up to 1000°C), high linearity, miniaturized size, and perfect mechanical property.

  7. Monolithic columns in plant proteomics and metabolomics.

    Science.gov (United States)

    Rigobello-Masini, Marilda; Penteado, José Carlos Pires; Masini, Jorge Cesar

    2013-03-01

    Since "omics" techniques emerged, plant studies, from biochemistry to ecology, have become more comprehensive. Plant proteomics and metabolomics enable the construction of databases that, with the help of genomics and informatics, show the data obtained as a system. Thus, all the constituents of the system can be seen with their interactions in both space and time. For instance, perturbations in a plant ecosystem as a consequence of application of herbicides or exposure to pollutants can be predicted by using information gathered from these databases. Analytical chemistry has been involved in this scientific evolution. Proteomics and metabolomics are emerging fields that require separation, identification, and quantification of proteins, peptides, and small molecules of metabolites in complex biological samples. The success of this work relies on efficient chromatographic and electrophoretic techniques, and on mass spectrometric detection. This paper reviews recent developments in the use of monolithic columns, focusing on their applications in "top-down" and "bottom-up" approaches, including their use as supports for immobilization of proteolytic enzymes and their use in two-dimensional and multidimensional chromatography. Whereas polymeric columns have been predominantly used for separation of proteins and polypeptides, silica-based monoliths have been more extensively used for separation of small molecules of metabolites. Representative applications in proteomics and in analysis of plant metabolites are given and summarized in tables.

  8. Growth techniques for monolithic YBCO solenoidal magnets

    Energy Technology Data Exchange (ETDEWEB)

    Scruggs, S.J. [Texas Center for Superconductivity at University of Houston, 4800 Calhoun, Houston, TX 77204 (United States)]. E-mail: Sscruggs2@uh.edu; Putman, P.T. [Texas Center for Superconductivity at University of Houston, 4800 Calhoun, Houston, TX 77204 (United States); Fang, H. [Texas Center for Superconductivity at University of Houston, 4800 Calhoun, Houston, TX 77204 (United States); Alessandrini, M. [Texas Center for Superconductivity at University of Houston, 4800 Calhoun, Houston, TX 77204 (United States); Salama, K. [Texas Center for Superconductivity at University of Houston, 4800 Calhoun, Houston, TX 77204 (United States)

    2006-10-01

    The possibility of growing large single domain YBCO solenoids by the use of a large seed has been investigated. There are two known methods for producing a similar solenoid. This first is a conventional top seeded melt growth process followed by a post processing machining step to create the bore. The second involves using multiple seeds spaced around the magnet bore. The appeal of the new technique lies in decreasing processing time compared to the single seed technique, while avoiding alignment problems found in the multiple seeding technique. By avoiding these problems, larger diameter monoliths can be produced. Large diameter monoliths are beneficial because the maximum magnetic field produced by a trapped field magnet is proportional to the radius of the sample. Furthermore, the availability of trapped field magnets with large diameter could enable their use in applications that traditionally have been considered to require wound electromagnets, such as beam bending magnets for particle accelerators or electric propulsion. A comparison of YBCO solenoids grown by the use of a large seed and grown by the use of two small seeds simulating multiple seeding is made. Trapped field measurements as well as microstructure evaluation were used in characterization of each solenoid. Results indicate that high quality growth occurs only in the vicinity of the seeds for the multiple seeded sample, while the sample with the large seeded exhibited high quality growth throughout the entire sample.

  9. High surface area, high permeability carbon monoliths

    Energy Technology Data Exchange (ETDEWEB)

    Lagasse, R.R.; Schroeder, J.L. [Sandia National Labs., Albuquerque, NM (United States). Organic Materials Processing Dept.

    1994-12-31

    The goal of this work is to prepare carbon monoliths having precisely tailored pore size distribution. Prior studies have demonstrated that poly(acrylonitrile) can be processed into a precursor having tailored macropore structure. Since the macropores were preserved during pyrolysis, this synthetic process provided a route to porous carbon having macropores with size =0.1 to 10{mu}m. No micropores of size <2 nm could be detected in the carbon, however, by nitrogen adsorption. In the present work, the authors have processed a different polymer, poly(vinylidene chloride) into a macroporous precursor, Pyrolysis produced carbon monoliths having macropores derived from the polymer precursor as well as extensive microporosity produced during the pyrolysis of the polymer. One of these carbons had BET surface area of 1,050 m{sup 2}/g and about 1.2 cc/g total pore volume, with about 1/3 of the total pore volume in micropores and the remainder in 1{mu}m macropores. No mesopores in the intermediate size range could be detected by nitrogen adsorption. Carbon materials having high surface area as well as micron size pores have potential applications as electrodes for double layer supercapacitors containing liquid electrolyte, or as efficient media for performing chemical separations.

  10. Hydrothermal method for preparing calcium phosphate monoliths

    Directory of Open Access Journals (Sweden)

    García Carrodeguas Raúl

    2003-01-01

    Full Text Available A new hydrothermal route for preparing biphasic calcium phosphate monoliths is proposed. Firstly, a slurry of beta-tricalcium phosphate/ortho-phosphoric acid (b-TCP/H3PO4 is cast into the desired final shape and size to obtain a block composed of dicalcium phosphate dihydrate (DCPD and b-TCP. This block is then treated in 1.0 M Na2HPO4 at 60 °C in order to hydrolyze the DCPD into Ca10-x(HPO4x(PO4 6-x(OH2-x (CDHA and Ca8H2(PO46 .5H2O (OCP. The result is a monolithic piece which preserves the initial shape and size, but which is composed instead of CDHA, OCP, and b-TCP. During the initial stage, when the pH is slightly alkaline, the product of DCPD hydrolysis is CDHA. However, when a neutral or slightly acidic pH is reached OCP is formed. Test samples processed by this method showed complete conversion of DCPD into CDHA and OCP after 112 h of hydrolysis, and with a compressive strength of 16.2 MPa, similar to cancellous bone.

  11. Catastrophic failure of a monolithic zirconia prosthesis.

    Science.gov (United States)

    Chang, Jae-Seung; Ji, Woon; Choi, Chang-Hoon; Kim, Sunjai

    2015-02-01

    Recently, monolithic zirconia restorations have received attention as an alternative to zirconia veneered with feldspathic porcelain to eliminate chipping failures of veneer ceramics. In this clinical report, a patient with mandibular edentulism received 4 dental implants in the interforaminal area, and a screw-retained monolithic zirconia prosthesis was fabricated. The patient also received a maxillary complete removable dental prosthesis over 4 anterior roots. At the 18-month follow-up, all of the zirconia cylinders were seen to be fractured, and the contacting abutment surfaces had lost structural integrity. The damaged abutments were replaced with new abutments, and a new prosthesis was delivered with a computer-assisted design and computer-assisted manufacturing fabricated titanium framework with denture teeth and denture base resins. At the 6-month recall, the patient did not have any problems. Dental zirconia has excellent physical properties; however, care should be taken to prevent excessive stresses on the zirconia cylinders when a screw-retained zirconia restoration is planned as a definitive prosthesis.

  12. Monolithic Ge-on-Si lasers for large-scale electronic-photonic integration

    Science.gov (United States)

    Liu, Jifeng; Kimerling, Lionel C.; Michel, Jurgen

    2012-09-01

    A silicon-based monolithic laser source has long been envisioned as a key enabling component for large-scale electronic-photonic integration in future generations of high-performance computation and communication systems. In this paper we present a comprehensive review on the development of monolithic Ge-on-Si lasers for this application. Starting with a historical review of light emission from the direct gap transition of Ge dating back to the 1960s, we focus on the rapid progress in band-engineered Ge-on-Si lasers in the past five years after a nearly 30-year gap in this research field. Ge has become an interesting candidate for active devices in Si photonics in the past decade due to its pseudo-direct gap behavior and compatibility with Si complementary metal oxide semiconductor (CMOS) processing. In 2007, we proposed combing tensile strain with n-type doping to compensate the energy difference between the direct and indirect band gap of Ge, thereby achieving net optical gain for CMOS-compatible diode lasers. Here we systematically present theoretical modeling, material growth methods, spontaneous emission, optical gain, and lasing under optical and electrical pumping from band-engineered Ge-on-Si, culminated by recently demonstrated electrically pumped Ge-on-Si lasers with >1 mW output in the communication wavelength window of 1500-1700 nm. The broad gain spectrum enables on-chip wavelength division multiplexing. A unique feature of band-engineered pseudo-direct gap Ge light emitters is that the emission intensity increases with temperature, exactly opposite to conventional direct gap semiconductor light-emitting devices. This extraordinary thermal anti-quenching behavior greatly facilitates monolithic integration on Si microchips where temperatures can reach up to 80 °C during operation. The same band-engineering approach can be extended to other pseudo-direct gap semiconductors, allowing us to achieve efficient light emission at wavelengths previously

  13. Stretchable and foldable silicon-based electronics

    KAUST Repository

    Cavazos Sepulveda, Adrian Cesar

    2017-03-30

    Flexible and stretchable semiconducting substrates provide the foundation for novel electronic applications. Usually, ultra-thin, flexible but often fragile substrates are used in such applications. Here, we describe flexible, stretchable, and foldable 500-μm-thick bulk mono-crystalline silicon (100) “islands” that are interconnected via extremely compliant 30-μm-thick connectors made of silicon. The thick mono-crystalline segments create a stand-alone silicon array that is capable of bending to a radius of 130 μm. The bending radius of the array does not depend on the overall substrate thickness because the ultra-flexible silicon connectors are patterned. We use fracture propagation to release the islands. Because they allow for three-dimensional monolithic stacking of integrated circuits or other electronics without any through-silicon vias, our mono-crystalline islands can be used as a “more-than-Moore” strategy and to develop wearable electronics that are sufficiently robust to be compatible with flip-chip bonding.

  14. Enzyme kinetics by directly imaging a porous silicon microfluidic reactor using desorption/ionization on silicon mass spectrometry.

    Science.gov (United States)

    Nichols, Kevin P; Azoz, Seyla; Gardeniers, Han J G E

    2008-11-01

    Enzyme kinetics were obtained in a porous silicon microfluidic channel by combining an enzyme and substrate droplet, allowing them to react and deposit a small amount of residue on the channel walls, and then analyzing this residue by directly ionizing the channel walls using a matrix assisted laser desorption/ionization mass spectrometry (MALDI-MS) laser source. The porous silicon of the channel walls functions in a manner analogous to the matrix in MALDI-MS, and is referred to as a desorption/ionization on silicon mass spectrometry (DIOS-MS) target when used in this configuration. Mass spectrometry signal intensity of substrate residue correlates with relative concentration, and position in the microchannel correlates with time, thus allowing determination of kinetic parameters. The system is especially suitable for initial reaction velocity determination. This microreactor is broadly applicable to time-resolved kinetic assays as long as at least one substrate or product of the reaction is ionizable by DIOS-MS.

  15. A Monolithic active pixel sensor for ionizing radiation using a 180nm HV-SOI process

    CERN Document Server

    Hemperek, Tomasz; Krüger, Hans; Wermes, Norbert

    2014-01-01

    An improved SOI-MAPS (Silicon On Insulator Monolithic Active Pixel Sensor) for ionizing radiation based on Partially Depleted High Voltage SOI technology (PD-SOI) has been developed. Similar to existing Fully Depleted SOI-based (FD-SOI) MAPS, a buried silicon oxide inter-dielectric (BOX) layer is used to separate the CMOS electronics from the handle wafer which is used as a depleted charge collection layer while FD-SOI MAPS suffer from radiation damage such as transistor threshold voltage shifts due to charge traps in the oxide layers and charge states created at the silicon oxide boundaries (back gate effect). The XFAB 180-nm HV-SOI technology offers an additional isolation by deep non-depleted implant between the BOX layer and the active circuitry witch mitigates this problem. Therefore we see in this technology a high potential to implement radiation-tolerant MAPS with fast charge collection property. The design and measurement results from a first prototype are presented including charge collection in neu...

  16. A Monolithic Active Pixel Sensor for ionizing radiation using a 180 nm HV-SOI process

    Science.gov (United States)

    Hemperek, Tomasz; Kishishita, Tetsuichi; Krüger, Hans; Wermes, Norbert

    2015-10-01

    An improved SOI-MAPS (Silicon On Insulator Monolithic Active Pixel Sensor) for ionizing radiation based on thick-film High Voltage SOI technology (HV-SOI) has been developed. Similar to existing Fully Depleted SOI-based (FD-SOI) MAPS, a buried silicon oxide inter-dielectric (BOX) layer is used to separate the CMOS electronics from the handle wafer which is used as a depleted charge collection layer. FD-SOI MAPS suffers from radiation damage such as transistor threshold voltage shifts due to charge traps in the oxide layers and charge states created at the silicon oxide boundaries (back gate effect). The X-FAB 180-nm HV-SOI technology offers an additional isolation by deep non-depleted implant between the BOX layer and the active circuitry which mitigates this problem. Therefore we see in this technology a high potential to implement radiation-tolerant MAPS with fast charge collection property. The design and measurement results from a first prototype are presented including charge collection in neutron irradiated samples.

  17. Development of a Microchannel In Situ Propellant Production System

    Energy Technology Data Exchange (ETDEWEB)

    Brooks, Kriston P.; Rassat, Scot D.; TeGrotenhuis, Ward E.

    2005-09-01

    An in situ propellant production (ISPP) plant on future Mars robotic missions can produce oxygen (O2) and methane (CH4) that can be used for propellant for the return voyage. By producing propellants from Mars atmospheric carbon dioxide (CO2) and hydrogen (H2) brought from Earth, the initial mass launched in low Earth orbit can be reduced by 20% to 45%, as compared to carrying all of the propellant for a round-trip mission to the Mars surface from Earth. Pacific Northwest National Laboratory used microchannel architecture to develop a Mars-based In Situ Propellant Production (ISPP) system. This three year research and development effort focused on process intensification and system miniaturization of three primary subsystems: a thermochemical compressor, catalytic reactors, and components for separating gas phases from liquid phases. These systems were designed based on a robotic direct return mission scenario, but can be scaled up to human flight missions by simply numbering up the microchannel devices. The thermochemical compression was developed both using absorption and adsorption. A multichannel adsorption system was designed to meet the full-scale CO2 collection requirements using temperature swing adsorption. Each stage is designed to achieve a 10x compression of CO2. A compression ratio to collect Martian atmospheric CO2 at ~0.8 kPa and compress it to at least 100 kPa can be achieved with two adsorption stages in series. A compressor stage incorporates eight thermally coupled adsorption cells at various stages in the adsorption/desorption cycle to maximize the recuperation of thermal energy and provide a nearly continuous flow of CO2 to the downstream reactors. The thermochemically compressed CO2 is then mixed with hydrogen gas and fed to two reactors: a Sabatier Reaction unit and a Reverse Water/Gas Shift unit. The microchannel architecture allows better heat control than is possible in an adiabatic system, resulting in significantly higher conversion. The

  18. Preparation and Characterization of Temperature-responsive Porous Monoliths

    Institute of Scientific and Technical Information of China (English)

    ZHANG, Rongyue; QI, Li; XIN, Peiyong; YANG, Gengliang; CHEN, Yi

    2009-01-01

    A new temperature-responsive porous monolith has been prepared by surface-initiated activators generated by electron transfer atom transfer radical polymerization (AGET ATRP) grafting poly(N-isopropylacrylamide) (PNIPAAm) within the pores of the porous polymer monolith. The grafting copolymerization was carried out by a method based on a continuous flow-through technique without special deoxygenation procedure needed in the general ATRP. The addition of ascorbic acid could counteract the oxidation effect of oxygen diffusing into the reaction system. The resulting grafted monolith was characterized by a mercury intrusion method and the size of macropore was 3.65 μm, which was suitable for flow through the monolith for HPLC. The thermally responsive property of the grafted monolith was evaluated by HPLC using steroids with various hydrophobicities as probes. Through determination of retention factor of each steroid on the grafted monolith at different temperatures using water as mobile phase, it was found that the slope of the plot of retention factor of each steroid versus the temperature changed around the low critical solution temperature (LCST, 32 ℃) of PNIPAAm in water. It was relative to the grafted PNIPAAm temperature sensitivity that a hydrophobic and hydrophilic alternation would take place around its LCST.Based on this thermally responsive property, the grafted monolith was used as stationary phase for HPLC and to separate the steroids using water as mobile phase by changing the column temperature. As a mobile phase, water is much better than organic solvents concerning the environment.

  19. Influence of different carbon monolith preparation parameters on pesticide adsorption

    Directory of Open Access Journals (Sweden)

    Vukčević Marija

    2013-01-01

    Full Text Available The capacity of carbon monolith for pesticide removal from water, and the mechanism of pesticide interaction with carbon surface were examined. Different carbon monolith samples were obtained by varying the carbonization and activation parameters. In order to examine the role of surface oxygen groups in pesticide adsorption, carbon monolith surface was functionalized by chemical treatment in HNO3, H2O2 and KOH. The surface properties of the obtained samples were investigated by BET surface area, pore size distribution and temperature-programmed desorption. Adsorption of pesticides from aqueous solution onto activated carbon monolith samples was studied by using five pesticides belonging to different chemical groups (acetamiprid, dimethoate, nicosulfuron, carbofuran and atrazine. Presented results show that higher temperature of carbonization and the amount of activating agent allow obtaining microporous carbon monolith with higher amount of surface functional groups. Adsorption properties of the activated carbon monolith were more readily affected by the amount of the surface functional groups than by specific surface area. Results obtained by carbon monolith functionalisation showed that π-π interactions were the main force for adsorption of pesticides with aromatic structure, while acidic groups play an important role in adsorption of pesticides with no aromatic ring in the chemical structure.

  20. Monolithically integrated reconfigurable add-drop multiplexer for mode-division-multiplexing systems.

    Science.gov (United States)

    Wang, Shipeng; Wu, Hao; Tsang, Hon Ki; Dai, Daoxin

    2016-11-15

    An integrated reconfigurable optical add-drop multiplexer (ROADM) for mode-division-multiplexing systems is proposed and demonstrated for the first time, to the best of our knowledge. The present ROADM with four mode-channels is composed of a four-channel mode demultiplexer, four identical 2×2 thermo-optic Mach-Zehnder switches (MZSs), and a four-channel mode multiplexer, which are integrated monolithically on silicon. All the devices are designed for operation with TM polarization. The ROADM can add/drop any one of the mode channels freely by thermally turning on/off the corresponding MZS. For the added/dropped mode-channels, the excess loss is 1-5 dB, and the extinction ratio is 15-20 dB in the wavelength range of 1535-1565 nm.

  1. Advances in gallium arsenide monolithic microwave integrated-circuit technology for space communications systems

    Science.gov (United States)

    Bhasin, K. B.; Connolly, D. J.

    1986-01-01

    Future communications satellites are likely to use gallium arsenide (GaAs) monolithic microwave integrated-circuit (MMIC) technology in most, if not all, communications payload subsystems. Multiple-scanning-beam antenna systems are expected to use GaAs MMIC's to increase functional capability, to reduce volume, weight, and cost, and to greatly improve system reliability. RF and IF matrix switch technology based on GaAs MMIC's is also being developed for these reasons. MMIC technology, including gigabit-rate GaAs digital integrated circuits, offers substantial advantages in power consumption and weight over silicon technologies for high-throughput, on-board baseband processor systems. In this paper, current developments in GaAs MMIC technology are described, and the status and prospects of the technology are assessed.

  2. Preliminary comparison of monolithic and aperture optics for XRMF

    Energy Technology Data Exchange (ETDEWEB)

    Havrilla, G.J.; Worley, C.G.

    1997-08-01

    Comparisons between standard aperture optics and a custom designed monolithic capillary x-ray optic for the Kevex Omicron are presented. The results demonstrate the feasibility of retrofitting an Omicron with a monolithic capillary. Increased flux is observed especially at lower energies which results in an increase in sensitivity and potentially an increase in spatial resolution. Alignment is a critical factor in achieving optimal performance of the monolithic capillary. Further improvements in flux output, spot size and overall sensitivity are expected with better alignment.

  3. On monolithic stability and reinforcement analysis of high arch dams

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Monolithic stability safety and reinforcement based on monolithic stability are very important for arch dam design.In this paper,the issue is addressed based on deformation reinforcement theory.In this approach,plastic complementary energy norm can be taken as safety Index for monolithic stability.According to deformation reinforcement theory,the areas where unbalanced force exists require reinforcement,and the required reinforcement forces are just the unbalanced forces with opposite direction.Results show that areas with unbalanced force mainly concentrate in dam-toes,dam-heels and faults.

  4. Hierarchically Structured Monolithic ZSM-5 through Macroporous Silica Gel Zeolitization

    Institute of Scientific and Technical Information of China (English)

    Lei Qian; Zhao Tianbo; Li Fengyan; Zong Baoning; Tong Yangchuan

    2006-01-01

    The hierarchically structured ZSM-5 monolith was prepared through transforming the skeletons of the macroporous silica gel into ZSM-5 by the steam-assisted conversion method. The morphology and monolithic shapes of macroporous silica gel were well preserved. The hierarchically structured ZSM-5 monolith exhibited the hierarchical porosity, with mesopores and macropores existing inside the macroporous silica gel, and micropores formed by the ZSM-5. The products have been characterized properly by using the XRD, SEM and N2 adsorption-desorption methods.

  5. Preparation of carbon monoliths from orange peel for NOx retention

    Directory of Open Access Journals (Sweden)

    Liliana Giraldo

    2014-12-01

    Full Text Available A series of monoliths are prepared from orange peels and chemically activated with H3PO4, KOH, ZnCl2, and water vapor without a binder. The monoliths were characterized by N2 adsorption-desorption isotherms at 77 K, Boehm titrations and XPS. Thereafter, monoliths were tested for their ability to establish NOx retention. The results show that the retention capacities of NOx were a function of the textural properties and chemistries. The carbons synthesized with ZnCl2 and KOH retained similar amounts of NOx.

  6. A decoupled monolithic projection method for natural convection problems

    Science.gov (United States)

    Pan, Xiaomin; Kim, Kyoungyoun; Lee, Changhoon; Choi, Jung-Il

    2016-06-01

    We propose an efficient monolithic numerical procedure based on a projection method for solving natural convection problems. In the present monolithic method, the buoyancy, linear diffusion, and nonlinear convection terms are implicitly advanced by applying the Crank-Nicolson scheme in time. To avoid an otherwise inevitable iterative procedure in solving the monolithic discretized system, we use a linearization of the nonlinear convection terms and approximate block lower-upper (LU) decompositions along with approximate factorization. Numerical simulations demonstrate that the proposed method is more stable and computationally efficient than other semi-implicit methods, preserving temporal second-order accuracy.

  7. Silicon carbonitrides - a novel class of materials

    Energy Technology Data Exchange (ETDEWEB)

    Schoenfelder, H. (Max-Planck-Inst. of Metals Research, Lab. for Powder Metallurgy, Inst. of Materials Science, Stuttgart (Germany)); Aldinger, F. (Max-Planck-Inst. of Metals Research, Lab. for Powder Metallurgy, Inst. of Materials Science, Stuttgart (Germany)); Riedel, R. (Max-Planck-Inst. of Metals Research, Lab. for Powder Metallurgy, Inst. of Materials Science, Stuttgart (Germany) Univ. of Darmstadt, Inst. of Materials Science, Darmstadt (Germany))

    1993-11-01

    Silicon carbonitride monoliths derived from polymer powder compacts via polymer pyrolysis represent a new class of structural ceramic materials due to the complete coalescence of the powder particles during polymer decomposition and the formation of a uniform ceramic matrix free from any grain boundaries or secondary phases. The submicron pore channel system penetrating the material can be minimized in volume by infiltration of liquid polysilazane solution or by post-HIPing so that relative densities of 96 % can be reached. The monoliths are oxidation resistant up to 1600 C in air due to the formation of a highly pure silica oxidation layer and they exhibit a creep rate of 1.10[sup -6] s[sup -1] at 1650 C and 30 MPa load. Initially x-ray amorphous silicon carbonitride can be crystallized in nitrogen or in air to form Si[sub 3]N[sub 4]/SiC or Si[sub 3]N[sub 4]/SiC/C nanocomposites. (orig.).

  8. Novel Silicon Devices for Radiation Therapy Monitoring

    Energy Technology Data Exchange (ETDEWEB)

    Bruzzi, Mara, E-mail: mara.bruzzi@unifi.it

    2016-02-11

    Modern radiotherapy techniques pose specific constraints in radiation-monitoring and dosimetry due to the occurrence of small radiation fields with high dose gradients, variation in space and time of the dose rate, variation in space and time of the beam energy spectrum. Novel devices coping with these strict conditions are needed. This paper reviews the most advanced technologies developed with silicon-based materials for clinical radiotherapy. Novel Si diodes as Pt-doped Si, epitaxial Si as well as thin devices have optimized performance, their response being independent of the accumulated dose, thus ensuring radiation tolerance and no need of recalibration. Monolithic devices based on segmented Si detectors can be easily tailored to optimize spatial resolution in the large active areas required in clinical radiotherapy. In particular, a monolithic device based on epitaxial p-type silicon, characterized by high spatial resolution and ability to directly measure temporal variations in dose modulation proved to be best viable solution for pre-treatment verifications in IMRT fields.

  9. Monolithically Peltier-cooled laser diodes

    Energy Technology Data Exchange (ETDEWEB)

    Hava, S.; Hunsperger, R.G.; Sequeira, H.B.

    1984-04-01

    A new method of cooling a GaAs/GaAlAs laser in an optical integrated circuit or on a discrete chip, by adding an integral thermoelectric (Peltier) cooling and heat spreading device to the laser, is presented. This cooling both reduces and stabilizes the laser junction temperature to minimize such deleterious effects as wavelength drift due to heating. A unified description of the electrical and thermal properties of a monolithic semiconductor mesa structure is given. Here it is shown that an improvement in thermal characteristics is obtained by depositing a relatively thick metallic layer, and by using this layer as a part of an active Peltier structure. Experimental results reveal a 14-percent increase in emitted power (external quantum efficiency) due to passive heat spreading and a further 8-percent if its Peltier cooler is operated. Fabrication techniques used to obtain devices exhibiting the above performance characteristics are given. 21 references.

  10. LSST primary/tertiary monolithic mirror

    Science.gov (United States)

    Sebag, J.; Gressler, W.; Liang, M.; Neill, D.; Araujo-Hauck, C.; Andrew, J.; Angeli, G.; Cho, M.; Claver, C.; Daruich, F.; Gessner, C.; Hileman, E.; Krabbendam, V.; Muller, G.; Poczulp, G.; Repp, R.; Wiecha, O.; Xin, B.; Kenagy, K.; Martin, H. M.; Tuell, M. T.; West, S. C.

    2016-08-01

    At the core of the Large Synoptic Survey Telescope (LSST) three-mirror optical design is the primary/tertiary (M1M3) mirror that combines these two large mirrors onto one monolithic substrate. The M1M3 mirror was spin cast and polished at the Steward Observatory Mirror Lab at The University of Arizona (formerly SOML, now the Richard F. Caris Mirror Lab at the University of Arizona (RFCML)). Final acceptance of the mirror occurred during the year 2015 and the mirror is now in storage while the mirror cell assembly is being fabricated. The M1M3 mirror will be tested at RFCML after integration with its mirror cell before being shipped to Chile.

  11. A monolithic thin film electrochromic window

    Energy Technology Data Exchange (ETDEWEB)

    Goldner, R.B.; Arntz, F.O.; Berera, G.; Haas, T.E.; Wong, K.K. (Tufts Univ., Medford, MA (United States). Electro-Optics Technology Center); Wei, G. (Mobil Solar Energy Corp., Billerica, MA (United States)); Yu, P.C. (PPG Industries, Inc., Monroeville, PA (United States))

    1991-01-01

    Three closely related thin film solid state ionic devices that are potentially important for applications are: electrochromic smart windows, high energy density thin film rechargeable batteries, and thin film electrochemical sensors. Each usually has at least on mixed ion/electron conductor, an electron-blocking ion conductor, and an ion-blocking electron conductor, and many of the technical issues associated with thin film solid state ionics are common to all three devices. Since the electrochromic window has the added technical requirement of electrically-controlled optical modulation, (over the solar spectrum), and since research at the authors' institution has focused primarily on the window structure, this paper will address the electrochromic window, and particularly a monolithic variable reflectivity electrochromic window, as an illustrative example of some of the challenges and opportunities that are confronting the thin film solid state ionics community. 33 refs.

  12. A monolithic thin film electrochromic window

    Energy Technology Data Exchange (ETDEWEB)

    Goldner, R.B.; Arntz, F.O.; Berera, G.; Haas, T.E.; Wong, K.K. [Tufts Univ., Medford, MA (United States). Electro-Optics Technology Center; Wei, G. [Mobil Solar Energy Corp., Billerica, MA (United States); Yu, P.C. [PPG Industries, Inc., Monroeville, PA (United States)

    1991-12-31

    Three closely related thin film solid state ionic devices that are potentially important for applications are: electrochromic smart windows, high energy density thin film rechargeable batteries, and thin film electrochemical sensors. Each usually has at least on mixed ion/electron conductor, an electron-blocking ion conductor, and an ion-blocking electron conductor, and many of the technical issues associated with thin film solid state ionics are common to all three devices. Since the electrochromic window has the added technical requirement of electrically-controlled optical modulation, (over the solar spectrum), and since research at the authors` institution has focused primarily on the window structure, this paper will address the electrochromic window, and particularly a monolithic variable reflectivity electrochromic window, as an illustrative example of some of the challenges and opportunities that are confronting the thin film solid state ionics community. 33 refs.

  13. Machining distortion prediction of aerospace monolithic components

    Institute of Scientific and Technical Information of China (English)

    Yun-bo BI; Qun-lin CHENG; Hui-yue DONG; Ying-lin KE

    2009-01-01

    To predict the distortion of aerospace monolithic components.a model is established to simulate the numerical control (NC)milling process using 3D finite element method(FEM).In this model,the cutting layer is simplified firstly.Then,the models of cutting force and cutting temperature are established to gain the cutting loads,which are applied to the mesh model of the part.Finally,a prototype of machining simulation environment is developed to simulate the milling process of a spar.Key factors influencing the distortion,such as initial residual stress,cutting loads,fixture layout,cutting sequence,and tool path are considered all together.The total distortion of the spar is predicted and an experiment is conducted to validate the numerical results.It is found that the maximum discrepancy between the simulation results and experiment values is 19.0%

  14. Solid oxide fuel cell having monolithic core

    Science.gov (United States)

    Ackerman, J. P.; Young, J. E.

    1983-10-01

    A solid oxide fuel cell is described for electrochemically combining fuel and oxidant for generating galvanic output, wherein the cell core has an array of electrolyte and interconnect walls that are substantially devoid of any composite inert materials for support. The core is monolithic, where each electrolyte wall consists of thin layers of cathode and anode materials sandwiching a thin layer of electrolyte material. The electrolyte walls are arranged and backfolded between adjacent interconnect walls operable to define a plurality of core passageways alternately arranged where the inside faces have only the anode material or only the cathode material exposed. Each layer of the electrolyte and interconnect materials 0.002 to 0.01 cm thick; and each layer of the cathode and anode materials is 0.002 to 0.05 cm thick.

  15. Silver deposition on chemically treated carbon monolith

    Directory of Open Access Journals (Sweden)

    Jovanović Zoran M.

    2009-01-01

    Full Text Available Carbon monolith was treated with HNO3, KOH and H2O2. Effects of these treatments on the surface functional groups and on the amount of silver deposited on the CM surface were studied by temperature programmed desorption (TPD and atomic absorption spectrometry (AAS. As a result of chemical treatment there was an increase in the amount of surface oxygen complexes. The increase in the amount of silver deposit is proportional to the amount of surface groups that produce CO under decomposition. However, the high amount of CO groups, decomposing above 600°C, induces the smaller Ag crystallite size. Therefore, the high temperature CO evolving oxides are, most likely, the initial centers for Ag deposition.

  16. High Flux Microchannel Receiver Development with Adap-tive Flow Control

    Energy Technology Data Exchange (ETDEWEB)

    Drost, Kevin [Oregon State Univ., Corvallis, OR (United States)

    2015-08-15

    This project is focused on the demonstration of a microchannel-based solar receiver (MSR). The MSR concept consists of using a modular arrangement of arrayed microchannels to heat a working fluid in a concentrating solar receiver, allowing a much higher solar flux on the receiver and consequently a significant reduction in thermal losses, size, and cost.

  17. Experimental and theoretical analysis of defocused CO2 laser microchanneling on PMMA for enhanced surface finish

    Science.gov (United States)

    Prakash, Shashi; Kumar, Subrata

    2017-02-01

    The poor surface finish of CO2 laser-micromachined microchannel walls is a major limitation of its utilization despite several key advantages, like low fabrication cost and low time consumption. Defocused CO2 laser beam machining is an effective solution for fabricating smooth microchannel walls on polymer and glass substrates. In this research work, the CO2 laser microchanneling process on PMMA has been analyzed at different beam defocus positions. Defocused processing has been investigated both theoretically and experimentally, and the depth of focus and beam diameter have been determined experimentally. The effect of beam defocusing on the microchannel width, depth, surface roughness, heat affected zone and microchannel profile were examined. A previously developed analytical model for microchannel depth prediction has been improved by incorporating the threshold energy density factor. A semi-analytical model for predicting the microchannel width at different defocus positions has been developed. A semi-empirical model has also been developed for predicting microchannel widths at different defocusing conditions for lower depth values. The developed models were compared and verified by performing actual experiments. Multi-objective optimization was performed to select the best optimum set of input parameters for achieving the desired surface roughness.

  18. Application of atomic layer deposited microchannel plates to imaging photodetectors with high time resolution

    Energy Technology Data Exchange (ETDEWEB)

    Siegmund, O; McPhate, J; Tremsin, Anton S; Vallerga, J V; Ertley, C D; Richner, N J; Gerard, T M; Frisch, H.; Elam, Jeffrey W.; Mane, Anil U.; Wagner, Robert G.; Minot, Michael J.; O' Mahony, Aileen O; Craven, C A

    2015-07-01

    Novel microchannel plates have been constructed using borosilicate glass micro-capillary array substrates with 20 mu m and 10 mu m pores and coated with resistive, and secondary electron emissive, layers by atomic layer deposition. Microchannel plates in 33 mm, 50 mm and 20 cm square formats have been made and tested. Although their amplification, imaging, and timing properties are comparable to standard glass microchannel plates, the background rates and lifetime characteristics are considerably improved. Sealed tube detectors based on the Planacon tube, and a 25 mm cross delay line readout tube with a GaN(Mg) opaque photocathode deposited on borosilicate microchannel plates have been fabricated. Considerable progress has also been made with 20 cm microchannel plates for a 20 cm format sealed tube sensor with strip-line readout that is being developed for Cherenkov light detection.

  19. Application of atomic layer deposited microchannel plates to imaging photodetectors with high time resolution

    Energy Technology Data Exchange (ETDEWEB)

    Siegmund, O.H.W., E-mail: ossy@ssl.berkeley.edu [Experimental Astrophysics Group, Space Sciences Laboratory, 7 Gauss Way, University of California, Berkeley, CA 94720 (United States); McPhate, J.B.; Tremsin, A.S.; Vallerga, J.V.; Ertley, C.D.; Richner, N.J.; Gerard, T.M. [Experimental Astrophysics Group, Space Sciences Laboratory, 7 Gauss Way, University of California, Berkeley, CA 94720 (United States); Frisch, H.J. [University of Chicago, 5640 S. Ellis Ave., Chicago, Il 60637 (United States); Elam, J.W.; Mane, A.U.; Wagner, R.G. [Argonne National Laboratory, 9700 S. Cass Ave. Lemont, Il 60439 (United States); Minot, M.J.; O' Mahony, A.; Craven, C.A. [Incom Inc., 294 Southbridge Road, Charlton, MA, 01507 (United States)

    2015-07-01

    Novel microchannel plates have been constructed using borosilicate glass micro-capillary array substrates with 20 µm and 10 µm pores and coated with resistive, and secondary electron emissive, layers by atomic layer deposition. Microchannel plates in 33 mm, 50 mm and 20 cm square formats have been made and tested. Although their amplification, imaging, and timing properties are comparable to standard glass microchannel plates, the background rates and lifetime characteristics are considerably improved. Sealed tube detectors based on the Planacon tube, and a 25 mm cross delay line readout tube with a GaN(Mg) opaque photocathode deposited on borosilicate microchannel plates have been fabricated. Considerable progress has also been made with 20 cm microchannel plates for a 20 cm format sealed tube sensor with strip-line readout that is being developed for Cherenkov light detection.

  20. Microchannel refill: a new method for fabricating 2D nanochannels in polymer substrates.

    Science.gov (United States)

    Li, Jing-min; Liu, Chong; Ke, Xue; Xu, Zheng; Duan, Ya-jie; Fan, Yan; Li, Meng; Zhang, Kai-ping; Wang, Li-ding

    2012-10-21

    In this paper, we present a new approach that is capable of fabricating nanochannels in a poly(methyl methacrylate) (PMMA) substrate. This method, which we call microchannel refill (MR), utilizes the refilling of glassy thermoplastics under thermal compression to reduce a microscopic channel to a nanochannel. It only has two main steps. First, a microchannel is fabricated in a PMMA substrate using normal hot embossing. Second, the microchannel is compressed under a certain temperature and pressure to obtain a nanochannel. We show that a nanochannel with a width as small as 132 nm (with a depth of 85 nm) can be easily produced by choosing the appropriate compression temperature, compression pressure, original microchannel width and original microchannel aspect ratio. Compared with most current nanochannel fabrication methods, MR is a quick, simple and cost-effective way to produce nanochannels in polymer substrates.

  1. Development of high-aspect-ratio microchannel heat exchanger based on multi-tool milling process

    Institute of Scientific and Technical Information of China (English)

    潘敏强; 李金恒; 汤勇

    2008-01-01

    A high-aspect-ratio microchannel heat exchanger based on multi-tool milling process was developed. Several slotting cutters were stacked together for simultaneously machining several high-aspect-ratio microchannels with manifold structures. On the basis of multi-tool milling process, the structural design of the manifold side height, microchannel length, width, number, and interval were analyzed. The heat transfer performances of high-aspect-ratio microchannel heat exchangers with two different manifolds were investigated by experiments, and the influencing factors were analyzed. The results indicate that the magnitude of heat transfer area per unit volume dominates the heat transfer performances of plate-type micro heat exchanger, while the velocity distribution between microchannels has little effects on the heat transfer performances.

  2. Cell Trapping Utilizing Insulator-based Dielectrophoresis in The Open-Top Microchannels

    CERN Document Server

    Jen, Chun-Ping; Chen, Teng-Wen

    2008-01-01

    The ability to manipulate or separate a biological small particle, such as a living cell and embryo, is fundamental needed to many biological and medical applications. The insulator-based dielectrophoresis (iDEP) trapping is composed of conductless tetragon structures in micro-chip. In this study, a lower conductive material of photoresist was adopted as a structure in open-top microchannel instead of a metallic wire to squeeze the electric field in a conducting solution, therefore, creating a high field gradient with a local maximum. The microchip with the open-top microchannels was designed and fabricated herein. The insulator-based DEP trapping microchip with the open-top microchannels was designed and fabricated in this work. The cells trapped by DEP force could be further treated or cultured in the open-top microchannel ; however, those trapped in the microchip with enclosed microchannels could not be proceeded easily.

  3. Monolithic Rare Earth Doped PTR Glass Laser Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The main goal of the project is to demonstrate the feasibility of a monolithic solid state laser on the basis of PTR glass co-doped with luminescent rare earth ions....

  4. Plant oil-based shape memory polymer using acrylic monolith

    Directory of Open Access Journals (Sweden)

    T. Tsujimoto

    2015-09-01

    Full Text Available This article deals with the synthesis of a plant oil-based material using acrylic monolith. An acrylic monolith bearing oxirane groups was prepared via simple technique that involved the dissolution of poly(glycidyl methacrylate-comethyl methacrylate (PGMA in ethanolic – aqueous solution by heating and subsequent cooling. The PGMA monolith had topologically porous structure, which was attributed to the phase separation of the polymer solution. The PGMA monolith was impregnated by epoxidized soybean oil (ESO containing thermally-latent catalyst, and the subsequent curing produced a crosslinked material with relatively good transparency. The Young’s modulus and the tensile strength of polyESO/PGMA increased compared with the ESO homopolymer. The strain at break of polyESO/PGMA was larger than that of the ESO homopolymer and crosslinked PGMA. Furthermore, polyESO/PGMA exhibited good shape memory-recovery behavior.

  5. Application of monolithic chromatographic supports in virus research.

    Science.gov (United States)

    Krajacic, Mladen; Ravnikar, Maja; Štrancar, Aleš; Gutiérrez-Aguirre, Ion

    2017-05-12

    Key properties of monolithic chromatographic supports, make them suitable for separation and/or concentration of large biomolecules, especially virus particles and viral genomes. One by one, the studies that have been completed so far, contributed to the knowledge that monolith chromatography has hardly any limitation to be applied in virus research. Viruses of different sizes, possessing icosahedral structure and symmetrical morphology, as well as rod-shaped or filamentous viruses with helical structure, even enveloped ones, all of them could be successfully managed by means of monolith chromatography. Same is true for viral genomes, primarily when being distinct from other nucleic acid forms present in a host cell. This review is exclusively focused on viruses. It describes the application of monolith chromatography to different problematics within the virus research field. The reviewed achievements offer new possibilities and trigger new aspects in virology. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  6. Effect of accelerated aging on translucency of monolithic zirconia

    Directory of Open Access Journals (Sweden)

    O. Abdelbary

    2016-12-01

    Conclusion: Thickness of zirconia has significant effect on translucency. Aging has significant effect on thinner sections of zirconia. More research is required on zirconia towards making the material more translucent for its potential use as esthetic monolithic restoration.

  7. Monolithic CMOS pixel detector for international linear collider vertex detection

    Indian Academy of Sciences (India)

    J E Brau; O Igonkina; N Sinew; D Strom; C Baltay; W Emmet; H Neal; D Rabinowitz

    2007-12-01

    A monolithic CMS pixel detector is under development for an ILC experiment. This chronopixel array provides a time stamp resolution of one bunch crossing, a critical feature for background suppression. The status of this effort is summarized.

  8. CTO recanalization by intraocclusion injection of contrast: the microchannel technique.

    Science.gov (United States)

    Carlino, Mauro; Latib, Azeem; Godino, Cosmo; Cosgrave, John; Colombo, Antonio

    2008-01-01

    To assess the utilization of microinjection of contrast for the recanalization of chronic total occlusions (CTO). Microchannels in CTOs have been considered important conduits for CTO crossing, utilizing dedicated guidewires. We postulated that microinjection of contrast immediately distal to the proximal cap of the CTO could identify and enlarge these microvessels, creating a passage for crossing the CTO with a floppy guidewire. A total of 32 patients with a CTO were treated with this technique. Following few millimetres penetration of the proximal fibrous cap of the occlusion with a dedicated CTO guidewire, the over-the-wire balloon was advanced into the proximal portion of the occlusion, and 50-100 microg of nitroglycerine followed by 1 ml of contrast was gently injected into the occluded segment. Technical success of the microchannel technique was defined as the ability to visualize the distal true lumen with microinjection of contrast and thereafter cross the CTO with a floppy guidewire in the absence of any dissection. Overall, technical success of the microchannel technique was obtained in 20 (63%) with angiographic success in 19. In 12 (37%) cases there was a technical failure because of dissection, and we obtained recanalization of the artery in 7 of these 12 cases with another technique. There was only one case of periprocedural myocardial infarction in an unsuccessful procedure and no major adverse cardiac events or subacute stent thromboses were observed. Microinjection of contrast immediately distal to the proximal fibrous cap of a CTO may be an additional technique to facilitate recanalization of CTO. Copyright 2008 Wiley-Liss, Inc.

  9. Filter-matrix lattice Boltzmann model for microchannel gas flows.

    Science.gov (United States)

    Zhuo, Congshan; Zhong, Chengwen

    2013-11-01

    The lattice Boltzmann method has been shown to be successful for microscale gas flows, and it has attracted significant research interest. In this paper, the recently proposed filter-matrix lattice Boltzmann (FMLB) model is first applied to study the microchannel gas flows, in which a Bosanquet-type effective viscosity is used to capture the flow behaviors in the transition regime. A kinetic boundary condition, the combined bounce-back and specular-reflection scheme with the second-order slip scheme, is also designed for the FMLB model. By analyzing a unidirectional flow, the slip velocity and the discrete effects related to the boundary condition are derived within the FMLB model, and a revised scheme is presented to overcome such effects, which have also been validated through numerical simulations. To gain an accurate simulation in a wide range of Knudsen numbers, covering the slip and the entire transition flow regimes, a set of slip coefficients with an introduced fitting function is adopted in the revised second-order slip boundary condition. The periodic and pressure-driven microchannel flows have been investigated by the present model in this study. The numerical results, including the velocity profile and the mass flow rate, as well as the nonlinear pressure distribution along the channel, agree fairly well with the solutions of the linearized Boltzmann equation, the direct simulation Monte Carlo results, the experimental data, and the previous results of the multiple effective relaxation lattice Boltzmann model. Also, the present results of the velocity profile and the mass flow rate show that the present model with the fitting function can yield improved predictions for the microchannel gas flow with higher Knudsen numbers in the transition flow regime.

  10. Propagation Behaviors of an Acid Wavefront Through a Microchannel Junction.

    Science.gov (United States)

    Nabika, Hideki; Hasegawa, Takahiko; Unoura, Kei

    2015-07-30

    Waves in reaction-diffusion systems yield a wealth of dynamic self-assembling phenomena in nature. Recent studies have been devoted to utilizing these active waves in conjunction with microscale technology. To provide a compass for controlling reaction-diffusion waves in microspaces, we have investigated the propagation behavior of one specific variety of the reaction-diffusion wave: an acid wave that utilizes an autocatalytic proton-production reaction. Furthermore, the acid wave that we have investigated occurs in a microchannel with a junction connecting circular and straight regions. The obtained results were compared with a neutralization wave that involves only a neutralization reaction. The acid wave was ignited by the addition of the appropriate amount of H2SO4 into the circular region that was filled with a substrate solution, where proton-consuming and proton-producing reactions followed a rapid neutralization reaction. At this stage, the wave penetrated and propagated into the channel region. Comparison between the acid and the neutralization waves clarified that the acid wave required a minimum threshold of H2SO4 concentration in order to be ignited and that the propagation of the acid wave was temporarily delayed because of the presence of intermediate chemical reaction steps. Furthermore, the propagation dynamics was found to be tuned through the configuration of the microchannel. The importance of microchannel configuration, especially for systems with a junction connecting different shapes, is discussed in terms of Fick's law and in terms of the proton flux from the circular to the straight regions.

  11. Inertial migration of deformable droplets in a microchannel

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Xiaodong; Xue, Chundong; Hu, Guoqing, E-mail: guoqing.hu@imech.ac.cn, E-mail: sunjs@nanoctr.cn [State Key Laboratory of Nonlinear Mechanics, Institute of Mechanics, Chinese Academy of Sciences, Beijing 100190 (China); Zhang, Li [Research and Development Center, Synfuels China Technology Co., Ltd., Beijing 101407 (China); Jiang, Xingyu; Sun, Jiashu, E-mail: guoqing.hu@imech.ac.cn, E-mail: sunjs@nanoctr.cn [Beijing Engineering Research Center for BioNanotechnology and Key Lab for Biological Effects of Nanomaterials and Nanosafety, National Center for Nanoscience and Technology, Beijing 100190 (China)

    2014-11-15

    The microfluidic inertial effect is an effective way of focusing and sorting droplets suspended in a carrier fluid in microchannels. To understand the flow dynamics of microscale droplet migration, we conduct numerical simulations on the droplet motion and deformation in a straight microchannel. The results are compared with preliminary experiments and theoretical analysis. In contrast to most existing literature, the present simulations are three-dimensional and full length in the streamwise direction and consider the confinement effects for a rectangular cross section. To thoroughly examine the effect of the velocity distribution, the release positions of single droplets are varied in a quarter of the channel cross section based on the geometrical symmetries. The migration dynamics and equilibrium positions of the droplets are obtained for different fluid velocities and droplet sizes. Droplets with diameters larger than half of the channel height migrate to the centerline in the height direction and two equilibrium positions are observed between the centerline and the wall in the width direction. In addition to the well-known Segré-Silberberg equilibrium positions, new equilibrium positions closer to the centerline are observed. This finding is validated by preliminary experiments that are designed to introduce droplets at different initial lateral positions. Small droplets also migrate to two equilibrium positions in the quarter of the channel cross section, but the coordinates in the width direction are between the centerline and the wall. The equilibrium positions move toward the centerlines with increasing Reynolds number due to increasing deformations of the droplets. The distributions of the lift forces, angular velocities, and the deformation parameters of droplets along the two confinement direction are investigated in detail. Comparisons are made with theoretical predictions to determine the fundamentals of droplet migration in microchannels. In

  12. Direct Measurement of Particle Inertial Migration in Rectangular Microchannels

    CERN Document Server

    Hood, Kaitlyn; Di Carlo, Dino; Roper, Marcus

    2015-01-01

    Particles traveling at high velocities through microfluidic channels migrate across streamlines due to inertial lift forces. There are contradictory theories predicting how the inertial lift force depends on flow parameters, but little experimental evidence by which to validate theory. Here we directly measure particle migration velocities and show agreement with numerical simulations and a two-term asymptotic theory that contains no unmeasured parameters. Our data also highlight the previously unconsidered effect of migration forces that act on particles before they enter the microchannel.

  13. Dead-time effects in microchannel-plate imaging detectors

    Science.gov (United States)

    Zombeck, Martin V.; Fraser, George W.

    1991-01-01

    The observed counting rates of microchannel plate (MCP) based detectors for high resolution observations of celestial EUV and X-ray sources vary over many orders of magnitude; the counting capability of an individual channel, however, is not high, and is associated with dead-times ranging from 0.1 msec to 1 sec. The dead-time increases with the area illuminated; attention is presently given to laboratory determinations of the count rate characteristics of a MCP detector as a function of illuminated area, and a model is developed for these results' use in the interpretation of space observations.

  14. Characteristics and applications of advanced technology microchannel plates

    Science.gov (United States)

    Horton, Jerry R.; Tasker, G. William; Fijol, John J.

    1990-10-01

    A method for fabrication of novel thin-filrn continuous dynode electron multipliers is described. We have shown the feasibility of crucial manufacturing steps, including anisotropic dry etching of substrates into photolithographically-defined arrays of high-aspect-ratio channels, and the formation of thin-film continuous dynodes by chemical vapor deposition. We discuss potential performance and design advantages of this advanced technology microchannel plate (AT-MCP) over the conven tional reduced lead silicate glass inicrochannel plate (RLSG-'MCP) and implications for new applications.

  15. Angular Sensitivity of Gated Micro-Channel Plate Framing Cameras

    Energy Technology Data Exchange (ETDEWEB)

    Landen, O L; Lobban, A; Tutt, T; Bell, P M; Costa, R; Ze, F

    2000-07-24

    Gated, microchannel-plate-based (MCP) framing cameras have been deployed worldwide for 0.2 - 9 keV x-ray imaging and spectroscopy of transient plasma phenomena. For a variety of spectroscopic and imaging applications, the angular sensitivity of MCPs must be known for correctly interpreting the data. We present systematic measurements of angular sensitivity at discrete relevant photon energies and arbitrary MCP gain. The results can been accurately predicted by using a simple 2D approximation to the 3D MCP geometry and by averaging over all possible photon ray paths.

  16. Microchannel laminated mass exchanger and method of making

    Science.gov (United States)

    Martin, Peter M.; Bennett, Wendy D.; Matson, Dean W.; Stewart, Donald C.; Drost, Monte K.; Wegeng, Robert S.; Perez, Joseph M.; Feng, Xiangdong; Liu, Jun

    2000-01-01

    The present invention is a microchannel mass exchanger having a first plurality of inner thin sheets and a second plurality of outer thin sheets. The inner thin sheets each have a solid margin around a circumference, the solid margin defining a slot through the inner thin sheet thickness. The outer thin sheets each have at least two header holes on opposite ends and when sandwiching an inner thin sheet. The outer thin sheets further have a mass exchange medium. The assembly forms a closed flow channel assembly wherein fluid enters through one of the header holes into the slot and exits through another of the header holes after contacting the mass exchange medium.

  17. Analytical heat and fluid flow in microchannels and microsystems

    CERN Document Server

    Cotta, Renato M; Naveira-Cotta, Carolina P

    2016-01-01

    This book focuses on the modeling and analysis of heat and fluid flow in microchannels and micro-systems, compiling a number of analytical and hybrid numerical-analytical solutions for models that account for the relevant micro-scale effects, with the corresponding experimental analysis validation when applicable. The volume stands as the only available compilation of easy to use analytically-based solutions for micro-scale heat and fluid flow problems, that systematically incorporates the most relevant micro-scale effects into the mathematical models, followed by their physical interpretation on the micro-system behavior.

  18. Computational technology of multiscale modeling the gas flows in microchannels

    Science.gov (United States)

    Podryga, V. O.

    2016-11-01

    The work is devoted to modeling the gas mixture flows in engineering microchannels under conditions of many scales of computational domain. The computational technology of using the multiscale approach combining macro - and microscopic models is presented. At macrolevel the nature of the flow and the external influence on it are considered. As a model the system of quasigasdynamic equations is selected. At microlevel the correction of gasdynamic parameters and the determination of boundary conditions are made. As a numerical model the Newton's equations and the molecular dynamics method are selected. Different algorithm types used for implementation of multiscale modeling are considered. The results of the model problems for separate stages are given.

  19. Process for making unsaturated hydrocarbons using microchannel process technology

    Science.gov (United States)

    Tonkovich, Anna Lee; Yuschak, Thomas; LaPlante, Timothy J.; Rankin, Scott; Perry, Steven T.; Fitzgerald, Sean Patrick; Simmons, Wayne W.; Mazanec, Terry Daymo, Eric

    2011-04-12

    The disclosed invention relates to a process for converting a feed composition comprising one or more hydrocarbons to a product comprising one or more unsaturated hydrocarbons, the process comprising: flowing the feed composition and steam in contact with each other in a microchannel reactor at a temperature in the range from about 200.degree. C. to about 1200.degree. C. to convert the feed composition to the product, the process being characterized by the absence of catalyst for converting the one or more hydrocarbons to one or more unsaturated hydrocarbons. Hydrogen and/or oxygen may be combined with the feed composition and steam.

  20. Dynamics of Capillary-Driven Flow in 3D Printed Open Microchannels.

    Science.gov (United States)

    Lade, Robert K; Hippchen, Erik J; Macosko, Christopher W; Francis, Lorraine F

    2017-03-28

    Microchannels have applications in microfluidic devices, patterns for micromolding, and even flexible electronic devices. Three-dimensional (3D) printing presents a promising alternative manufacturing route for these microchannels due to the technology's relative speed and the design freedom it affords its users. However, the roughness of 3D printed surfaces can significantly influence flow dynamics inside of a microchannel. In this work, open microchannels are fabricated using four different 3D printing techniques: fused deposition modeling (FDM), stereolithography (SLA), selective laser sintering, and multi jet modeling. Microchannels printed with each technology are evaluated with respect to their surface roughness, morphology, and how conducive they are to spontaneous capillary filling. Based on this initial assessment, microchannels printed with FDM and SLA are chosen as models to study spontaneous, capillary-driven flow dynamics in 3D printed microchannels. Flow dynamics are investigated over short (∼10(-3) s), intermediate (∼1 s), and long (∼10(2) s) time scales. Surface roughness causes a start-stop motion down the channel due to contact line pinning, while the cross-sectional shape imparted onto the channels during the printing process is shown to reduce the expected filling velocity. A significant delay in the onset of Lucas-Washburn dynamics (a long-time equilibrium state where meniscus position advances proportionally to the square root of time) is also observed. Flow dynamics are assessed as a function of printing technology, print orientation, channel dimensions, and liquid properties. This study provides the first in-depth investigation of the effect of 3D printing on microchannel flow dynamics as well as a set of rules on how to account for these effects in practice. The extension of these effects to closed microchannels and microchannels fabricated with other 3D printing technologies is also discussed.

  1. Functional recordings from awake, behaving rodents through a microchannel based regenerative neural interface

    Science.gov (United States)

    Gore, Russell K.; Choi, Yoonsu; Bellamkonda, Ravi; English, Arthur

    2015-02-01

    Objective. Neural interface technologies could provide controlling connections between the nervous system and external technologies, such as limb prosthetics. The recording of efferent, motor potentials is a critical requirement for a peripheral neural interface, as these signals represent the user-generated neural output intended to drive external devices. Our objective was to evaluate structural and functional neural regeneration through a microchannel neural interface and to characterize potentials recorded from electrodes placed within the microchannels in awake and behaving animals. Approach. Female rats were implanted with muscle EMG electrodes and, following unilateral sciatic nerve transection, the cut nerve was repaired either across a microchannel neural interface or with end-to-end surgical repair. During a 13 week recovery period, direct muscle responses to nerve stimulation proximal to the transection were monitored weekly. In two rats repaired with the neural interface, four wire electrodes were embedded in the microchannels and recordings were obtained within microchannels during proximal stimulation experiments and treadmill locomotion. Main results. In these proof-of-principle experiments, we found that axons from cut nerves were capable of functional reinnervation of distal muscle targets, whether regenerating through a microchannel device or after direct end-to-end repair. Discrete stimulation-evoked and volitional potentials were recorded within interface microchannels in a small group of awake and behaving animals and their firing patterns correlated directly with intramuscular recordings during locomotion. Of 38 potentials extracted, 19 were identified as motor axons reinnervating tibialis anterior or soleus muscles using spike triggered averaging. Significance. These results are evidence for motor axon regeneration through microchannels and are the first report of in vivo recordings from regenerated motor axons within microchannels in a small

  2. Performance characteristics between monolithic and microservice-based systems

    OpenAIRE

    Flygare, Robin; Holmqvist, Anthon

    2017-01-01

    A new promising technology to face the problem of scalability and availability is the microservice architecture. The problem with this architecture is that there is no significant study that clearly proves the performance differences compared to the monolithic architecture. Our thesis aims to provide a more conclusive answer of how the microservice architecture differs performance wise compared to the monolithic architecture. In this study, we conducted several experiments on a self-developed...

  3. Sol-Gel Synthesis of Non-Silica Monolithic Materials

    Directory of Open Access Journals (Sweden)

    Bartłomiej Gaweł

    2010-04-01

    Full Text Available Monolithic materials have become very popular because of various applications, especially within chromatography and catalysis. Large surface areas and multimodal porosities are great advantages for these applications. New sol-gel preparation methods utilizing phase separation or nanocasting have opened the possibility for preparing materials of other oxides than silica. In this review, we present different synthesis methods for inorganic, non-silica monolithic materials. Some examples of application of the materials are also included.

  4. Reliability Analysis and Optimal Design of Monolithic Vertical Wall Breakwaters

    DEFF Research Database (Denmark)

    Sørensen, John Dalsgaard; Burcharth, Hans F.; Christiani, E.

    1994-01-01

    Reliability analysis and reliability-based design of monolithic vertical wall breakwaters are considered. Probabilistic models of the most important failure modes, sliding failure, failure of the foundation and overturning failure are described . Relevant design variables are identified and relia......Reliability analysis and reliability-based design of monolithic vertical wall breakwaters are considered. Probabilistic models of the most important failure modes, sliding failure, failure of the foundation and overturning failure are described . Relevant design variables are identified...

  5. Extended Leach Testing of Simulated LAW Cast Stone Monoliths

    Energy Technology Data Exchange (ETDEWEB)

    Serne, R. Jeffrey [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Westsik, Joseph H. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Williams, Benjamin D. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Jung, H. B. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Wang, Guohui [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

    2015-07-09

    This report describes the results from long-term laboratory leach tests performed at Pacific Northwest National Laboratory (PNNL) for Washington River Protection Solutions (WRPS) to evaluate the release of key constituents from monoliths of Cast Stone prepared with four simulated low-activity waste (LAW) liquid waste streams. Specific objectives of the Cast Stone long-term leach tests described in this report focused on four activities: 1. Extending the leaching times for selected ongoing EPA-1315 tests on monoliths made with LAW simulants beyond the conventional 63-day time period up to 609 days reported herein (with some tests continuing that will be documented later) in an effort to evaluate long-term leaching properties of Cast Stone to support future performance assessment activities. 2. Starting new EPA-1315 leach tests on archived Cast Stone monoliths made with four LAW simulants using two leachants (deionized water [DIW] and simulated Hanford Integrated Disposal Facility (IDF) Site vadose zone pore water [VZP]). 3. Evaluating the impacts of varying the iodide loading (starting iodide concentrations) in one LAW simulant (7.8 M Na Hanford Tank Waste Operations Simulator (HTWOS) Average) by manufacturing new Cast Stone monoliths and repeating the EPA-1315 leach tests using DIW and the VZP leachants. 4. Evaluating the impacts of using a non-pertechnetate form of Tc that is present in some Hanford tanks. In this activity one LAW simulant (7.8 M Na HTWOS Average) was spiked with a Tc(I)-tricarbonyl gluconate species and then solidified into Cast Stone monoliths. Cured monoliths were leached using the EPA-1315 leach protocol with DIW and VZP. The leach results for the Tc-Gluconate Cast Stone monoliths were compared to Cast Stone monoliths pertechnetate.

  6. Cherenkov TOF PET with silicon photomultipliers

    Energy Technology Data Exchange (ETDEWEB)

    Dolenec, R., E-mail: rok.dolenec@ijs.si [Faculty of Chemistry and Chemical Engineering, University of Maribor, Maribor (Slovenia); Jožef Stefan Institute, Jamova cesta 39, SI-1000 Ljubljana (Slovenia); Faculty of Mathematics and Physics, University of Ljubljana, Ljubljana (Slovenia); Korpar, S. [Faculty of Chemistry and Chemical Engineering, University of Maribor, Maribor (Slovenia); Jožef Stefan Institute, Jamova cesta 39, SI-1000 Ljubljana (Slovenia); Križan, P. [Faculty of Mathematics and Physics, University of Ljubljana, Ljubljana (Slovenia); Jožef Stefan Institute, Jamova cesta 39, SI-1000 Ljubljana (Slovenia); Pestotnik, R. [Jožef Stefan Institute, Jamova cesta 39, SI-1000 Ljubljana (Slovenia)

    2015-12-21

    As previously demonstrated, an excellent timing resolution below 100 ps FWHM is possible in time-of-flight positron emission tomography (TOF PET) if the detection method is based on the principle of detecting photons of Cherenkov light, produced in a suitable material and detected by microchannel plate photomultipliers (MCP PMTs). In this work, the silicon photomultipliers (SiPMs) were tested for the first time as the photodetectors in Cherenkov TOF PET. The high photon detection efficiency (PDE) of SiPMs led to a large improvement in detection efficiency. On the other hand, the time response of currently available SiPMs is not as good as that of MCP PMTs. The SiPM dark counts introduce a new source of random coincidences in Cherenkov method, which would be overwhelming with present SiPM technology at room temperature. When the apparatus was cooled, its performance significantly improved.

  7. Mechanically stable, hierarchically porous Cu3(btc)2 (HKUST-1) monoliths via direct conversion of copper(II) hydroxide-based monoliths.

    Science.gov (United States)

    Moitra, Nirmalya; Fukumoto, Shotaro; Reboul, Julien; Sumida, Kenji; Zhu, Yang; Nakanishi, Kazuki; Furukawa, Shuhei; Kitagawa, Susumu; Kanamori, Kazuyoshi

    2015-02-28

    The synthesis of highly crystalline macro-meso-microporous monolithic Cu3(btc)2 (HKUST-1; btc(3-) = benzene-1,3,5-tricarboxylate) is demonstrated by direct conversion of Cu(OH)2-based monoliths while preserving the characteristic macroporous structure. The high mechanical strength of the monoliths is promising for possible applications to continuous flow reactors.

  8. Silicon Spintronics

    NARCIS (Netherlands)

    Jansen, R.

    2008-01-01

    Integration of magnetism and mainstream semiconductor electronics could impact information technology in ways beyond imagination. A pivotal step is implementation of spin-based electronic functionality in silicon devices. Remarkable progress made during the last two years gives confidence that this

  9. Reconfigurable liquid-core/liquid-cladding optical waveguides with dielectrophoresis-driven virtual microchannels on an electromicrofluidic platform.

    Science.gov (United States)

    Fan, Shih-Kang; Lee, Hsuan-Ping; Chien, Chia-Chi; Lu, Yi-Wen; Chiu, Yi; Lin, Fan-Yi

    2016-03-07

    An electrically reconfigurable liquid-core/liquid-cladding (L(2)) optical waveguide with core liquid γ-butyrolactone (GBL, ncore = 1.4341, εcore = 39) and silicone oil (ncladding = 1.401, εcladding = 2.5) as cladding liquid is accomplished using dielectrophoresis (DEP) that attracts and deforms the core liquid with the greater permittivity to occupy the region of strong electric field provided by Teflon-coated ITO electrodes between parallel glass plates. Instead of continuously flowing core and cladding liquids along a physical microchannel, the DEP-formed L(2) optical waveguide guides light in a stationary virtual microchannel that requires liquids of limited volume without constant supply and creates stable liquid/liquid interfaces for efficient light guidance in a simply fabricated microfluidic device. We designed and examined (1) stationary and (2) moving L(2) optical waveguides on the parallel-plate electromicrofluidic platform. In the stationary L-shaped waveguide, light was guided in a GBL virtual microchannel core for a total of 27.85 mm via a 90° bend (radius 5 mm) before exiting from the light outlet of cross-sectional area 100 μm × 100 μm. For the stationary spiral waveguide, light was guided in a GBL core containing Rhodamine 6G (R6G, 1 mM) and through a series of 90° bends with decreasing radii from 5 mm to 2.5 mm. With the stationary straight waveguide, the propagation loss was measured to be 2.09 dB cm(-1) in GBL with R6G (0.01 mM). The moving L-shaped waveguide was implemented on a versatile electromicrofluidic platform on which electrowetting and DEP were employed to generate a precise GBL droplet and form a waveguide core. On sequentially applying appropriate voltage to one of three parallel L-shaped driving electrodes, the GBL waveguide core was shifted; the guided light was switched at a speed of up to 0.929 mm s(-1) (switching period 70 ms, switching rate 14.3 Hz) when an adequate electric signal (173.1 VRMS, 100 kHz) was applied.

  10. Monoliths: A Review of the Basics, Preparation Methods and Their Relevance to Oxidation

    Directory of Open Access Journals (Sweden)

    Sandeeran Govender

    2017-02-01

    Full Text Available Considerable research has been conducted on monolithic catalysts for various applications. Strategies toward coating monoliths are of equal interest and importance. In this paper, the preparation of monoliths and monolithic catalysts have been summarized. More specifically, a brief explanation for the manufacturing of ceramic and metallic monoliths has been provided. Also, different methods for coating γ-alumina, as a secondary support, are included. Techniques used to deposit metal-based species, zeolites and carbon onto monoliths are discussed. Furthermore, monoliths extruded with metal oxides, zeolites and carbon are described. The main foci are on the reasoning and understanding behind the preparation of monolithic catalysts. Ideas and concerns are also contributed to encourage better approaches when designing these catalysts. More importantly, the relevance of monolithic structures to reactions, such as the selective oxidation of alkanes, catalytic combustion for power generation and the preferential oxidation of carbon monoxide, has been described.

  11. Polymethacrylate monolithic and hybrid particle-monolithic columns for reversed-phase and hydrophilic interaction capillary liquid chromatography.

    Science.gov (United States)

    Jandera, Pavel; Urban, Jirí; Skeríková, Veronika; Langmaier, Pavel; Kubícková, Romana; Planeta, Josef

    2010-01-01

    We prepared hybrid particle-monolithic polymethacrylate columns for micro-HPLC by in situ polymerization in fused silica capillaries pre-packed with 3-5microm C(18) and aminopropyl silica bonded particles, using polymerization mixtures based on laurylmethacrylate-ethylene dimethacrylate (co)polymers for the reversed-phase (RP) mode and [2-(methacryloyloxy)ethyl]-dimethyl-(3-sulfopropyl) zwitterionic (co)polymers for the hydrophilic interaction (HILIC) mode. The hybrid particle-monolithic columns showed reduced porosity and hold-up volumes, approximately 2-2.5 times lower in comparison to the pure monolithic columns prepared in the whole volume of empty capillaries. The elution volumes of sample compounds are also generally lower in comparison to packed or pure monolithic columns. The efficiency and permeability of the hybrid columns are intermediate in between the properties of the reference pure monolithic and particle-packed columns. The chemistries of the embedded solid particles and of the interparticle monolithic moiety in the hybrid capillary columns contribute to the retention to various degrees, affecting the selectivity of separation. Some hybrid columns provided improved separations of proteins in comparison to the reference particle-packed columns in the reversed-phase mode. Zwitterionic hybrid particle-monolithic columns show dual mode retention HILIC/RP behaviour depending on the composition of the mobile phase and allow separations of polar compounds such as phenolic acids in the HILIC mode at lower concentrations of acetonitrile and, often in shorter analysis time in comparison to particle-packed and full-volume monolithic columns.

  12. Biasable, Balanced, Fundamental Submillimeter Monolithic Membrane Mixer

    Science.gov (United States)

    Siegel, Peter; Schlecht, Erich; Mehdi, Imran; Gill, John; Velebir, James; Tsang, Raymond; Dengler, Robert; Lin, Robert

    2010-01-01

    This device is a biasable, submillimeter-wave, balanced mixer fabricated using JPL s monolithic membrane process a simplified version of planar membrane technology. The primary target application is instrumentation used for analysis of atmospheric constituents, pressure, temperature, winds, and other physical and chemical properties of the atmospheres of planets and comets. Other applications include high-sensitivity gas detection and analysis. This innovation uses a balanced configuration of two diodes allowing the radio frequency (RF) signal and local oscillator (LO) inputs to be separated. This removes the need for external diplexers that are inherently narrowband, bulky, and require mechanical tuning to change frequency. Additionally, this mixer uses DC bias-ability to improve its performance and versatility. In order to solve problems relating to circuit size, the GaAs membrane process was created. As much of the circuitry as possible is fabricated on-chip, making the circuit monolithic. The remainder of the circuitry is precision-machined into a waveguide block that holds the GaAs circuit. The most critical alignments are performed using micron-scale semiconductor technology, enabling wide bandwidth and high operating frequencies. The balanced mixer gets superior performance with less than 2 mW of LO power. This can be provided by a simple two-stage multiplier chain following an amplifier at around 90 GHz. Further, the diodes are arranged so that they can be biased. Biasing pushes the diodes closer to their switching voltage, so that less LO power is required to switch the diodes on and off. In the photo, the diodes are at the right end of the circuit. The LO comes from the waveguide at the right into a reduced-height section containing the diodes. Because the diodes are in series to the LO signal, they are both turned on and off simultaneously once per LO cycle. Conversely, the RF signal is picked up from the RF waveguide by the probe at the left, and flows

  13. Lithographically patterned silicon nanostructures on silicon substrates

    Energy Technology Data Exchange (ETDEWEB)

    Megouda, Nacera [Institut de Recherche Interdisciplinaire (IRI, USR 3078), Universite Lille1, Parc de la Haute Borne, 50 Avenue de Halley-BP 70478, 59658 Villeneuve d' Ascq and Institut d' Electronique, de Microelectronique et de Nanotechnologie (IEMN, CNRS-8520), Cite Scientifique, Avenue Poincare-B.P. 60069, 59652 Villeneuve d' Ascq (France); Faculte des Sciences, Universite Mouloud Mammeri, Tizi-Ouzou (Algeria); Unite de Developpement de la Technologie du Silicium (UDTS), 2 Bd. Frantz Fanon, B.P. 140 Alger-7 merveilles, Alger (Algeria); Piret, Gaeelle; Galopin, Elisabeth; Coffinier, Yannick [Institut de Recherche Interdisciplinaire (IRI, USR 3078), Universite Lille1, Parc de la Haute Borne, 50 Avenue de Halley-BP 70478, 59658 Villeneuve d' Ascq and Institut d' Electronique, de Microelectronique et de Nanotechnologie (IEMN, CNRS-8520), Cite Scientifique, Avenue Poincare-B.P. 60069, 59652 Villeneuve d' Ascq (France); Hadjersi, Toufik, E-mail: hadjersi@yahoo.com [Unite de Developpement de la Technologie du Silicium (UDTS), 2 Bd. Frantz Fanon, B.P. 140 Alger-7 merveilles, Alger (Algeria); Elkechai, Omar [Faculte des Sciences, Universite Mouloud Mammeri, Tizi-Ouzou (Algeria); and others

    2012-06-01

    The paper reports on controlled formation of silicon nanostructures patterns by the combination of optical lithography and metal-assisted chemical dissolution of crystalline silicon. First, a 20 nm-thick gold film was deposited onto hydrogen-terminated silicon substrate by thermal evaporation. Gold patterns (50 {mu}m Multiplication-Sign 50 {mu}m spaced by 20 {mu}m) were transferred onto the silicon wafer by means of photolithography. The etching process of crystalline silicon in HF/AgNO{sub 3} aqueous solution was studied as a function of the silicon resistivity, etching time and temperature. Controlled formation of silicon nanowire arrays in the unprotected areas was demonstrated for highly resistive silicon substrate, while silicon etching was observed on both gold protected and unprotected areas for moderately doped silicon. The resulting layers were characterized using scanning electron microscopy (SEM).

  14. Performance enhancement of PV cells through micro-channel cooling

    Directory of Open Access Journals (Sweden)

    Muzaffar Ali

    2015-11-01

    Full Text Available Efficiency of a PV cell is strongly dependent on its surface temperature. The current study is focused to achieve maximum efficiency of PV cells even in scorching temperatures in hot climates like Pakistan where the cell surface temperatures can even rise up to around 80 ℃. The study includes both the CFD and real time experimental investigations of a solar panel using micro channel cooling. Initially, CFD analysis is performed by developing a 3D model of a Mono-Crystalline cell with micro-channels to analyze cell surface temperature distribution at different irradiance and water flow rates. Afterwards, an experimental setup is developed for performance investigations under the real conditions of an open climate of a Pakistan's city, Taxila. Two 35W panels are manufactured for the experiments; one is based on the standard manufacturing procedure while other cell is developed with 4mm thick aluminum sheet having micro-channels of cross-section of 1mm by 1mm. The whole setup also includes different sensors for the measurement of solar irradiance, cell power, surface temperature and water flow rates. The experimental results show that PV cell surface temperature drop of around 15 ℃ is achieved with power increment of around 14% at maximum applied water flow rate of 3 LPM. Additionally, a good agreement is also found between CFD and experimental results. Therefore, that study clearly shows that a significant performance improvement of PV cells can be achieved through the proposed cell cooling technique.

  15. Stability Analysis of Reactive Multiphase Slug Flows in Microchannels

    Directory of Open Access Journals (Sweden)

    Alejandro A. Munera Parra

    2014-05-01

    Full Text Available Conducting multiphase reactions in micro-reactors is a promising strategy for intensifying chemical and biochemical processes. A major unresolved challenge is to exploit the considerable benefits offered by micro-scale operation for industrial scale throughputs by numbering-up whilst retaining the underlying advantageous flow characteristics of the single channel system in multiple parallel channels. Fabrication and installation tolerances in the individual micro-channels result in different pressure losses and, thus, a fluid maldistribution. In this work, an additional source of maldistribution, namely the flow multiplicities, which can arise in a multiphase reactive or extractive flow in otherwise identical micro-channels, was investigated. A detailed experimental and theoretical analysis of the flow stability with and without reaction for both gas-liquid and liquid-liquid slug flow has been developed. The model has been validated using the extraction of acetic acid from n-heptane with the ionic liquid 1-Ethyl-3-methylimidazolium ethyl sulfate. The results clearly demonstrate that the coupling between flow structure, the extent of reaction/extraction and pressure drop can result in multiple operating states, thus, necessitating an active measurement and control concept to ensure uniform behavior and optimal performance.

  16. Laminar flow of micropolar fluid in rectangular microchannels

    Institute of Scientific and Technical Information of China (English)

    Shangjun Ye; Keqin Zhu; Wen Wang

    2006-01-01

    Compared with the classic flow on macroscale, flows in microchannels have some new phenomena such as the friction increase and the flow rate reduction. Papautsky and co-workers explained these phenomena by using a micropolar fluid model where the effects of micro-rotation of fluid molecules were taken into account. But both the curl of velocity vector and the curl of micro-rotation gyration vector were given incorrectly in the Cartesian coordinates and then the micro-rotation gyration vector had only one component in the (z)-direction. Besides, the gradient term of the divergence of micro-rotation gyration vector was missed improperly in the angular moment equation. In this paper. the governing equations for laminar flows of micropolar fluid in rectangular microchannels are reconstructed. The numerical results of velocity profiles and micro-rotation gyrations are obtained by a procedure based on the Chebyshev collocation method. The micropolar effects on velocity and micro-rotation gyration are discussed in detail.

  17. Dynamics of droplet entrapment in a constricted microchannel

    Science.gov (United States)

    Nekouei, Mehdi; Bithi, Swastika; Vanapalli, Siva

    2016-11-01

    Droplet migration and clogging in confined geometries is a problem of fundamental importance in oil recovery and droplet microfluidics. A confined droplet flowing through a conduit can either be arrested at the constriction or squeeze through it. The dynamics of the trapped and squeezed states are expected to depend on capillary number, drop size, viscosity ratio. Although there have been a number of studies on the dynamics of droplets passing through a constriction, investigations of dynamics of trapped droplets in constricted microchannels is lacking. In this work, we performed three-dimensional simulations of droplet trapping and squeezing process in a constricted microchannel. We also conducted experiments to validate the key results of the simulations. We investigated the impact of different system parameters on the onset of droplet immobilization at the constriction. We found that the continuous phase flows through the corners of the droplet, i.e. gutter flows to play an important role in determining the transition between trapping and squeezing. Therefore we evaluated the effect of different system parameters on gutter flows and found that the hydrodynamic resistance of gutters depends on the viscosity, size and confinement of the droplet.

  18. Exopolysaccharide microchannels direct bacterial motility and organize multicellular behavior.

    Science.gov (United States)

    Berleman, James E; Zemla, Marcin; Remis, Jonathan P; Liu, Hong; Davis, Annie E; Worth, Alexandra N; West, Zachary; Zhang, Angela; Park, Hanwool; Bosneaga, Elena; van Leer, Brandon; Tsai, Wenting; Zusman, David R; Auer, Manfred

    2016-11-01

    The myxobacteria are a family of soil bacteria that form biofilms of complex architecture, aligned multilayered swarms or fruiting body structures that are simple or branched aggregates containing myxospores. Here, we examined the structural role of matrix exopolysaccharide (EPS) in the organization of these surface-dwelling bacterial cells. Using time-lapse light and fluorescence microscopy, as well as transmission electron microscopy and focused ion beam/scanning electron microscopy (FIB/SEM) electron microscopy, we found that Myxococcus xanthus cell organization in biofilms is dependent on the formation of EPS microchannels. Cells are highly organized within the three-dimensional structure of EPS microchannels that are required for cell alignment and advancement on surfaces. Mutants lacking EPS showed a lack of cell orientation and poor colony migration. Purified, cell-free EPS retains a channel-like structure, and can complement EPS(-) mutant motility defects. In addition, EPS provides the cooperative structure for fruiting body formation in both the simple mounds of M. xanthus and the complex, tree-like structures of Chondromyces crocatus. We furthermore investigated the possibility that EPS impacts community structure as a shared resource facilitating cooperative migration among closely related isolates of M. xanthus.

  19. Bubble nucleation in superhydrophobic microchannels due to subcritical heating

    Science.gov (United States)

    Cowley, Adam; Maynes, Daniel; Crockett, Julie; Iverson, Brian

    2016-11-01

    We report on experiments that investigate the effects of heating on laminar flow in superhydrophobic (SH) microchannels. The parallel plate microchannels (180 μm spacing) consist of two surfaces: a rib/cavity structured SH surface and a smooth glass surface. The back of the SH surface is in contact with an aluminum strip that is heated and a camera is used to image through the glass surface to visualize the flow. Thermocouples embedded in the aluminum obtain the temperature profile along the length of the channel. The friction factor-Reynolds product (fRe) is obtained via pressure drop and volumetric flow rate measurements. Five surface types/configurations are investigated: smooth hydrophilic, smooth hydrophobic, SH with ribs perpendicular to the flow, SH with ribs parallel to the flow, and SH with both ribs parallel to the flow and sparse ribs perpendicular to the flow. Both degassed and air-saturated water are used. When air-saturated water is used, the cavities of the SH surfaces act as nucleation sites and air is desorbed out of the water. Depending on the surface type/configuration, large bubbles can form and result in a large increase in fRe and channel surface temperatures. When degassed water is used no bubble nucleation is observed, however, the air trapped in the cavities of the SH surfaces is quickly absorbed and the surfaces transition to a wetted state. This research was supported by the National Science Foundation (NSF) (Grant No. CBET-1235881).

  20. Tracking Submicron Particles in Microchannel Flow by Microscopic Holography

    Institute of Scientific and Technical Information of China (English)

    罗锐; 刘石

    2012-01-01

    Three-dimensional tracking of submicron particles in flows in a micro-channel was carried out using in-line holographic microscopy.A fixed single 0.5 μm fluorescent particle was identified and isolated from dust particles or overlapped particle pair using the laser induced fluorescent(LIF) method.Then in-line microscopic holograms of the fixed single particle were obtained at different positions on the optical axis,i.e.the defocus distances.The holograms of the single particle were used as the model templates with the known defocus distances.The particles in the in-line microscopic holograms of flow in the microchannel were then identified and located to obtain their two-dimensional positions.The defocus distances of those particles were determined by matching each hologram pattern to one of the model templates obtained in the single particle test.Finally the three-dimensional position and velocity of each particle were obtained.