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Sample records for microfabricated magnetic sifter

  1. Effect of Magnetic Field Gradient on Effectiveness of the Magnetic Sifter for Cell Purification.

    PubMed

    Ooi, Chinchun; Earhart, Christopher M; Wilson, Robert J; Wang, Shan X

    2013-01-01

    In our experiments with NCI-H1650 lung cancer cell lines labeled with magnetic nanoparticles via the Epithelial Cell Adhesion Molecule (EpCAM) antigen, we demonstrate capture efficiencies above 90% even at sample flow rates of 5 ml/h through our microfabricated magnetic sifter. We also improve the elution efficiencies from between 50% and 60% to close to 90% via optimization of the permanent magnet size and position used to magnetize the sifter. We then explain our observations via the use of finite element software for magnetic field and field gradient distributions, and a particle tracing algorithm, illustrating the impact of magnetic field gradients on the performance of the magnetic sifter. The high capture and elution efficiencies observed here is especially significant for magnetic separation of biologically interesting but rare moieties such as cancer stem cells for downstream analysis. PMID:23515873

  2. Effect of Magnetic Field Gradient on Effectiveness of the Magnetic Sifter for Cell Purification

    PubMed Central

    Ooi, Chinchun; Earhart, Christopher M.; Wilson, Robert J.; Wang, Shan X.

    2013-01-01

    In our experiments with NCI-H1650 lung cancer cell lines labeled with magnetic nanoparticles via the Epithelial Cell Adhesion Molecule (EpCAM) antigen, we demonstrate capture efficiencies above 90% even at sample flow rates of 5 ml/h through our microfabricated magnetic sifter. We also improve the elution efficiencies from between 50% and 60% to close to 90% via optimization of the permanent magnet size and position used to magnetize the sifter. We then explain our observations via the use of finite element software for magnetic field and field gradient distributions, and a particle tracing algorithm, illustrating the impact of magnetic field gradients on the performance of the magnetic sifter. The high capture and elution efficiencies observed here is especially significant for magnetic separation of biologically interesting but rare moieties such as cancer stem cells for downstream analysis. PMID:23515873

  3. Magnetic sifters and biochips for early diagnosis and therapy monitoring of cancer

    NASA Astrophysics Data System (ADS)

    Earhart, Chris

    2008-03-01

    Magnetic nanoparticles conjugated with biomolecules or recognition moieties are finding wide applications in medicine. In this context, we are developing a micromachined magnetic sifter and magnetic nanoparticles aimed for sample preparation applications in early diagnosis of cancer. The microfabricated sifter consisting of arrays of micron sized slits etched through a silicon wafer. A magnetic film is deposited on the wafer, producing high magnetic field gradients, comparable in magnitude to gradients in planar flow devices. As the solution flows through the die, magnetic particles are captured by the magnetic material surrounding the slits. The large number of slits allows for processing of large volumes of liquid, much greater than that of planar microfluidic devices. The sifters can be simply attached to a syringe or tube, resulting in a portable and user-friendly tool for molecular biology. Separation efficiencies of ˜ 50% for one pass through the sifter have been achieved. We have also designed and fabricated several types of magnetic biochips consisting of arrays of giant magnetoresistive (GMR) spin valve detectors with appropriate dimensions, surface chemistry, and microfluidics. An advanced electronic test station has been set up as a demonstration vehicle for the integrated evaluation of our magnetic biochips with commercial and custom magnetic nanoparticle labels for DNA or protein biomarkers. The magnetic biochip is capable of detecting down to 1-30 nanotags. Real-time detection of DNA signatures and protein targets in buffer and serum samples has been successfully performed in our laboratories, suggesting that magnetic biochips hold great promises for molecular diagnostics of cancer and other diseases. In collaboration with Chris M. Earhart, Wei Hu, Robert J. Wilson, Sebastian J. Osterfeld, Robert L. White, Nader Pourmand, and Shan X. Wang @ Stanford University. This work was supported by grants from NIH (1U54CA119367-01) and DARPA/Navy (N00014-02-1-0807).

  4. Isolation and mutational analysis of circulating tumor cells from lung cancer patients with magnetic sifters and biochips†

    PubMed Central

    Earhart, Christopher M.; Hughes, Casey E.; Gaster, Richard S.; Ooi, Chin Chun; Wilson, Robert J.; Zhou, Lisa Y.; Humke, Eric W.; Xu, Lingyun; Wong, Dawson J.; Willingham, Stephen B.; Schwartz, Erich J.; Weissman, Irving L.; Jeffrey, Stefanie S.; Neal, Joel W.; Rohatgi, Rajat; Wakelee, Heather A.; Wang, Shan X.

    2014-01-01

    Detection and characterization of circulating tumor cells (CTCs) may reveal insights into the diagnosis and treatment of malignant disease. Technologies for isolating CTCs developed thus far suffer from one or more limitations, such as low throughput, inability to release captured cells, and reliance on expensive instrumentation for enrichment or subsequent characterization. We report a continuing development of a magnetic separation device, the magnetic sifter, which is a miniature microfluidic chip with a dense array of magnetic pores. It offers high efficiency capture of tumor cells, labeled with magnetic nanoparticles, from whole blood with high throughput and efficient release of captured cells. For subsequent characterization of CTCs, an assay, using a protein chip with giant magnetoresistive nanosensors, has been implemented for mutational analysis of CTCs enriched with the magnetic sifter. The use of these magnetic technologies, which are separate devices, may lead the way to routine preparation and characterization of “liquid biopsies” from cancer patients. PMID:23969419

  5. Spin annihilations of and spin sifters for transverse electric and transverse magnetic waves in co- and counter-rotations

    PubMed Central

    Mok, Jinsik

    2014-01-01

    Summary This study is motivated in part to better understand multiplexing in wireless communications, which employs photons carrying varying angular momenta. In particular, we examine both transverse electric (TE) and transverse magnetic (TM) waves in either co-rotations or counter-rotations. To this goal, we analyze both Poynting-vector flows and orbital and spin parts of the energy flow density for the combined fields. Consequently, we find not only enhancements but also cancellations between the two modes. To our surprise, the photon spins in the azimuthal direction exhibit a complete annihilation for the counter-rotational case even if the intensities of the colliding waves are of different magnitudes. In contrast, the orbital flow density disappears only if the two intensities satisfy a certain ratio. In addition, the concepts of spin sifters and enantiomer sorting are illustrated. PMID:25383300

  6. Rapid Characterization of Magnetic Moment of Cells for Magnetic Separation

    PubMed Central

    Ooi, Chinchun; Earhart, Christopher M.; Wilson, Robert J.; Wang, Shan X.

    2014-01-01

    NCI-H1650 lung cancer cell lines labeled with magnetic nanoparticles via the Epithelial Cell Adhesion Molecule (EpCAM) antigen were previously shown to be captured at high efficiencies by a microfabricated magnetic sifter. If fine control and optimization of the magnetic separation process is to be achieved, it is vital to be able to characterize the labeled cells’ magnetic moment rapidly. We have thus adapted a rapid prototyping method to obtain the saturation magnetic moment of these cells. This method utilizes a cross-correlation algorithm to analyze the cells’ motion in a simple fluidic channel to obtain their magnetophoretic velocity, and is effective even when the magnetic moments of cells are small. This rapid characterization is proven useful in optimizing our microfabricated magnetic sifter procedures for magnetic cell capture. PMID:24771946

  7. Rapid Characterization of Magnetic Moment of Cells for Magnetic Separation.

    PubMed

    Ooi, Chinchun; Earhart, Christopher M; Wilson, Robert J; Wang, Shan X

    2013-07-01

    NCI-H1650 lung cancer cell lines labeled with magnetic nanoparticles via the Epithelial Cell Adhesion Molecule (EpCAM) antigen were previously shown to be captured at high efficiencies by a microfabricated magnetic sifter. If fine control and optimization of the magnetic separation process is to be achieved, it is vital to be able to characterize the labeled cells' magnetic moment rapidly. We have thus adapted a rapid prototyping method to obtain the saturation magnetic moment of these cells. This method utilizes a cross-correlation algorithm to analyze the cells' motion in a simple fluidic channel to obtain their magnetophoretic velocity, and is effective even when the magnetic moments of cells are small. This rapid characterization is proven useful in optimizing our microfabricated magnetic sifter procedures for magnetic cell capture. PMID:24771946

  8. Microfabricated atomic vapor cell arrays for magnetic field measurements

    SciTech Connect

    Woetzel, S.; Schultze, V.; IJsselsteijn, R.; Schulz, T.; Anders, S.; Stolz, R.; Meyer, H.-G.

    2011-03-15

    We describe a method for charging atomic vapor cells with cesium and buffer gas. By this, it is possible to adjust the buffer gas pressure in the cells with good accuracy. Furthermore, we present a new design of microfabricated vapor cell arrays, which combine silicon wafer based microfabrication and ultrasonic machining to achieve the arrays of thermally separated cells with 50 mm{sup 3} volume. With cells fabricated in the outlined way, intrinsic magnetic field sensitivities down to 300 fT/Hz{sup 1/2} are reached.

  9. Microfabrication of High Resolution X-ray Magnetic Calorimeters

    SciTech Connect

    Hsieh, W.-T.; Stevenson, Thomas R.; Bandler, Simon R.; Kelly, Daniel P.; Porst, Jan P.; Rotzinger, Hannes; Seidel, George M.

    2009-12-16

    Metallic magnetic calorimeter (MMC) is one of the most promising x-ray detector technologies for providing the very high energy resolution needed for future astronomical x-ray imaging spectroscopy. For this purpose, we have developed micro-fabricated 5x5 arrays of MMC of which each individual pixel has excellent energy resolution as good as 3.4 eV at 6 keV x-ray. Here we report on the fabrication techniques developed to achieve good resolution and high efficiency. These include: processing of a thin insulation layer for strong magnetic coupling between the AuEr sensor film and the niobium pick-up coil; production of overhanging absorbers for enhanced efficiency of x-ray absorption; fabrication on SiN membranes to minimize the effects on energy resolution from athermal phonon loss. We have also improved the deposition of the magnetic sensor film such that the film magnetization is nearly completely that is expected from the AuEr sputter target bulk material. In addition, we have included a study of a positional sensitive design, the Hydra design, which allows thermal coupling of four absorbers to a common MMC sensor and circuit.

  10. Microfabrication of High Resolution X-ray Magnetic Calorimeters

    NASA Astrophysics Data System (ADS)

    Hsieh, Wen-Ting; Bandler, Simon R.; Kelly, Daniel P.; Porst, Jan P.; Rotzinger, Hannes; Seidel, George M.; Stevenson, Thomas R.

    2009-12-01

    Metallic magnetic calorimeter (MMC) is one of the most promising x-ray detector technologies for providing the very high energy resolution needed for future astronomical x-ray imaging spectroscopy. For this purpose, we have developed micro-fabricated 5×5 arrays of MMC of which each individual pixel has excellent energy resolution as good as 3.4 eV at 6 keV x-ray. Here we report on the fabrication techniques developed to achieve good resolution and high efficiency. These include: processing of a thin insulation layer for strong magnetic coupling between the AuEr sensor film and the niobium pick-up coil; production of overhanging absorbers for enhanced efficiency of x-ray absorption; fabrication on SiN membranes to minimize the effects on energy resolution from athermal phonon loss. We have also improved the deposition of the magnetic sensor film such that the film magnetization is nearly completely that is expected from the AuEr sputter target bulk material. In addition, we have included a study of a positional sensitive design, the Hydra design, which allows thermal coupling of four absorbers to a common MMC sensor and circuit.

  11. Microfabricated Ion Beam Drivers for Magnetized Target Fusion

    NASA Astrophysics Data System (ADS)

    Persaud, Arun; Seidl, Peter; Ji, Qing; Ardanuc, Serhan; Miller, Joseph; Lal, Amit; Schenkel, Thomas

    2015-11-01

    Efficient, low-cost drivers are important for Magnetized Target Fusion (MTF). Ion beams offer a high degree of control to deliver the required mega joules of driver energy for MTF and they can be matched to several types of magnetized fuel targets, including compact toroids and solid targets. We describe an ion beam driver approach based on the MEQALAC concept (Multiple Electrostatic Quadrupole Array Linear Accelerator) with many beamlets in an array of micro-fabricated channels. The channels consist of a lattice of electrostatic quadrupoles (ESQ) for focusing and of radio-frequency (RF) electrodes for ion acceleration. Simulations with particle-in-cell and beam envelope codes predict >10x higher current densities compared to state-of-the-art ion accelerators. This increase results from dividing the total ion beam current up into many beamlets to control space charge forces. Focusing elements can be biased taking advantage of high breakdown electric fields in sub-mm structures formed using MEMS techniques (Micro-Electro-Mechanical Systems). We will present results on ion beam transport and acceleration in MEMS based beamlets. Acknowledgments: This work is supported by the U.S. DOE under Contract No. DE-AC02-05CH11231.

  12. 7 CFR 58.224 - Sifters.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 7 Agriculture 3 2010-01-01 2010-01-01 false Sifters. 58.224 Section 58.224 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL MARKETING SERVICE (Standards, Inspections, Marketing Practices), DEPARTMENT OF AGRICULTURE (CONTINUED) REGULATIONS AND STANDARDS UNDER THE AGRICULTURAL MARKETING ACT OF 1946 AND THE...

  13. 7 CFR 58.224 - Sifters.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 7 Agriculture 3 2013-01-01 2013-01-01 false Sifters. 58.224 Section 58.224 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL MARKETING SERVICE (Standards, Inspections, Marketing Practices), DEPARTMENT OF AGRICULTURE (CONTINUED) REGULATIONS AND STANDARDS UNDER THE AGRICULTURAL MARKETING ACT OF 1946 AND THE...

  14. Evaluation of Magnetic Resonance Imaging Issues for Implantable Microfabricated Magnetic Actuators

    PubMed Central

    Lee, Hyowon; Xu, Qing; Shellock, Frank G.; Bergsneider, Marvin; Judy, Jack W.

    2013-01-01

    The mechanical robustness of microfabricated torsional magnetic actuators in withstanding the strong static fields (7 T) and time-varying field gradients (17 T/m) produced by an MR system was studied in this investigation. The static and dynamic mechanical characteristics of 30 devices were quantitatively measured before and after exposure to both strong uniform and non-uniform magnetic fields. The results showed no statistically significant change in both the static and dynamic mechanical performance, which mitigate concerns about the mechanical stability of these devices in association with MR systems under the conditions used for this assessment. The MR-induced heating was also measured in a 3-T/128-MHz MR system. The results showed a minimal increase (1.6 °C) in temperature due to the presence of the magnetic microactuator array. Finally, the size of the MR-image artifacts created by the magnetic microdevices were quantified. The signal loss caused by the devices was approximately four times greater than the size of the device. PMID:24077662

  15. Development of Microfabricated Magnetic Actuators for Removing Cellular Occlusion

    PubMed Central

    Lee, Selene A.; Lee, Hyowon; Pinney, James R; Khialeeva, Elvira; Bergsneider, Marvin; Judy, Jack W.

    2011-01-01

    Here we report on the development of torsional magnetic microactuators for displacing biological materials in implantable catheters. Static and dynamic behaviors of the devices were characterized in air and in fluid using optical experimental methods. The devices were capable of achieving large deflections (>60°) and had resonant frequencies that ranged from 70 Hz to 1.5 kHz in fluid. The effect of long-term actuation (>2.5 · 108 cycles) was quantified using resonant shift as the metric (Δf < 2%). Cell-clearing capabilities of the devices were evaluated by examining the effect of actuation on a layer of aggressively growing adherent cells. On average, actuated microdevices removed 37.4% of the adherent cell layer grown over the actuator surface. The effect of actuation time, deflection angle, and beam geometry were evaluated. The experimental results indicate that physical removal of adherent cells at the microscale is feasible using magnetic microactuation. PMID:21886945

  16. A microfabricated coil for implantable applications of magnetic spinal cord stimulation.

    PubMed

    Yu-Min Fu; Che-Yu Chen; Xin-Hong Qian; Yu-Ting Cheng; Chung-Yu Wu; Jui-Sheng Sun; Chien-Chun Huang; Chao-Kai Hu

    2015-08-01

    In this paper, a microfabricated inductive coil comprising of 125-turn coil windings and a MnZn-based magnetic core in a volume of 200 mm(3) is presented for the magnetic neural stimulation in a spinal cord. The coil winding with the parallel-linkage design instead of the typical serial-linkage one is proposed not only to provide better design flexibility to the current mode driving circuit but also to simplify the fabrication process of the 3-D inductive coil, which can further advance the coil miniaturization. Experimental results show the microcoil with a 1.5 A, 1 kHz square-wave current input can induce a voltages of ~220 μV on the conducting wire with an impedance of ~0.2 Ω @ 1 kHz, 1 mm separation. PMID:26737882

  17. SIFTER search: a web server for accurate phylogeny-based protein function prediction.

    PubMed

    Sahraeian, Sayed M; Luo, Kevin R; Brenner, Steven E

    2015-07-01

    We are awash in proteins discovered through high-throughput sequencing projects. As only a minuscule fraction of these have been experimentally characterized, computational methods are widely used for automated annotation. Here, we introduce a user-friendly web interface for accurate protein function prediction using the SIFTER algorithm. SIFTER is a state-of-the-art sequence-based gene molecular function prediction algorithm that uses a statistical model of function evolution to incorporate annotations throughout the phylogenetic tree. Due to the resources needed by the SIFTER algorithm, running SIFTER locally is not trivial for most users, especially for large-scale problems. The SIFTER web server thus provides access to precomputed predictions on 16 863 537 proteins from 232 403 species. Users can explore SIFTER predictions with queries for proteins, species, functions, and homologs of sequences not in the precomputed prediction set. The SIFTER web server is accessible at http://sifter.berkeley.edu/ and the source code can be downloaded. PMID:25979264

  18. SIFTER search: a web server for accurate phylogeny-based protein function prediction

    SciTech Connect

    Sahraeian, Sayed M.; Luo, Kevin R.; Brenner, Steven E.

    2015-05-15

    We are awash in proteins discovered through high-throughput sequencing projects. As only a minuscule fraction of these have been experimentally characterized, computational methods are widely used for automated annotation. Here, we introduce a user-friendly web interface for accurate protein function prediction using the SIFTER algorithm. SIFTER is a state-of-the-art sequence-based gene molecular function prediction algorithm that uses a statistical model of function evolution to incorporate annotations throughout the phylogenetic tree. Due to the resources needed by the SIFTER algorithm, running SIFTER locally is not trivial for most users, especially for large-scale problems. The SIFTER web server thus provides access to precomputed predictions on 16 863 537 proteins from 232 403 species. Users can explore SIFTER predictions with queries for proteins, species, functions, and homologs of sequences not in the precomputed prediction set. Lastly, the SIFTER web server is accessible at http://sifter.berkeley.edu/ and the source code can be downloaded.

  19. SIFTER search: a web server for accurate phylogeny-based protein function prediction

    DOE PAGESBeta

    Sahraeian, Sayed M.; Luo, Kevin R.; Brenner, Steven E.

    2015-05-15

    We are awash in proteins discovered through high-throughput sequencing projects. As only a minuscule fraction of these have been experimentally characterized, computational methods are widely used for automated annotation. Here, we introduce a user-friendly web interface for accurate protein function prediction using the SIFTER algorithm. SIFTER is a state-of-the-art sequence-based gene molecular function prediction algorithm that uses a statistical model of function evolution to incorporate annotations throughout the phylogenetic tree. Due to the resources needed by the SIFTER algorithm, running SIFTER locally is not trivial for most users, especially for large-scale problems. The SIFTER web server thus provides access tomore » precomputed predictions on 16 863 537 proteins from 232 403 species. Users can explore SIFTER predictions with queries for proteins, species, functions, and homologs of sequences not in the precomputed prediction set. Lastly, the SIFTER web server is accessible at http://sifter.berkeley.edu/ and the source code can be downloaded.« less

  20. A microfabricated magnetic actuation device for mechanical conditioning of arrays of 3D microtissues.

    PubMed

    Xu, Fan; Zhao, Ruogang; Liu, Alan S; Metz, Tristin; Shi, Yu; Bose, Prasenjit; Reich, Daniel H

    2015-06-01

    This paper describes an approach to actuate magnetically arrays of microtissue constructs for long-term mechanical conditioning and subsequent biomechanical measurements. Each construct consists of cell/matrix material self-assembled around a pair of flexible poly(dimethylsiloxane) (PDMS) pillars. The deflection of the pillars reports the tissues' contractility. Magnetic stretching of individual microtissues via magnetic microspheres mounted on the cantilevers has been used to elucidate the tissues' elastic modulus and response to varying mechanical boundary conditions. This paper describes the fabrication of arrays of micromagnetic structures that can transduce an externally applied uniform magnetic field to actuate simultaneously multiple microtissues. These structures are fabricated on silicon-nitride coated Si wafers and contain electrodeposited Ni bars. Through-etched holes provide optical and culture media access when the devices are mounted on the PDMS microtissue scaffold devices. Both static and AC forces (up to 20 μN on each microtissue) at physiological frequencies are readily generated in external fields of 40 mT. Operation of the magnetic arrays was demonstrated via measurements of elastic modulus and dynamic stiffening in response to AC actuation of fibroblast populated collagen microtissues. PMID:25959132

  1. A microfabricated magnetic actuation device for mechanical conditioning of arrays of 3D microtissues

    PubMed Central

    Xu, Fan; Zhao, Ruogang; Liu, Alan S.; Metz, Tristin; Shi, Yu; Bose, Prasenjit; Reich, Daniel H.

    2015-01-01

    This paper describes an approach to actuate magnetically arrays of microtissue constructs for long-term mechanical conditioning and subsequent biomechanical measurements. Each construct consists of cell/matrix material self-assembled around a pair of flexible poly(dimethylsiloxane) (PDMS) pillars. The deflection of the pillars reports the tissues’ contractility. Magnetic stretching of individual microtissues via magnetic microspheres mounted on the cantilevers has been used to elucidate the tissues’ elastic modulus and response to varying mechanical boundary conditions. This paper describes the fabrication of arrays of micromagnetic structures that can transduce an externally applied uniform magnetic field to actuate simultaneously multiple microtissues. These structures are fabricated on silicon-nitride coated Si wafers and contain electrodeposited Ni bars. Through-etched holes provide optical and culture media access when the devices are mounted on the PDMS microtissue scaffold devices. Both static and AC forces (up to 20 μN on each microtissue) at physiological frequencies are readily generated in external fields of 40 mT. Operation of the magnetic arrays was demonstrated via measurements of elastic modulus and dynamic stiffening in response to AC actuation of fibroblast populated collagen microtissues. PMID:25959132

  2. Probing cellular traction forces with magnetic nanowires and microfabricated force sensor arrays

    NASA Astrophysics Data System (ADS)

    Lin, Yi-Chia; Kramer, Corinne M.; Chen, Christopher S.; Reich, Daniel H.

    2012-02-01

    In this paper, the use of magnetic nanowires for the study of cellular response to force is demonstrated. High-aspect ratio Ni rods with diameter 300 nm and lengths up to 20 μm were bound to or internalized by pulmonary artery smooth muscle cells (SMCs) cultured on arrays of flexible micropost force sensors. Forces and torques were applied to the cells by driving the nanowires with AC magnetic fields in the frequency range 0.1-10 Hz, and the changes in cellular contractile forces were recorded with the microposts. These local stimulations yield global force reinforcement of the cells’ traction forces, but this contractile reinforcement can be effectively suppressed upon addition of a calcium channel blocker, ruthenium red, suggesting the role of calcium channels in the mechanical response. The responsiveness of the SMCs to actuation depends on the frequency of the applied stimulation. These results show that the combination of magnetic nanoparticles and micropatterned, flexible substrates can provide new approaches to the study of cellular mechanotransduction.

  3. 7 CFR 58.246 - Cleaning of dryers, collectors, conveyors, ducts, sifters and storage bins.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 7 Agriculture 3 2010-01-01 2010-01-01 false Cleaning of dryers, collectors, conveyors, ducts, sifters and storage bins. 58.246 Section 58.246 Agriculture Regulations of the Department of Agriculture... Inspection and Grading Service 1 Operations and Operating Procedures § 58.246 Cleaning of dryers,...

  4. 7 CFR 58.246 - Cleaning of dryers, collectors, conveyors, ducts, sifters and storage bins.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 7 Agriculture 3 2012-01-01 2012-01-01 false Cleaning of dryers, collectors, conveyors, ducts, sifters and storage bins. 58.246 Section 58.246 Agriculture Regulations of the Department of Agriculture... Inspection and Grading Service 1 Operations and Operating Procedures § 58.246 Cleaning of dryers,...

  5. 7 CFR 58.246 - Cleaning of dryers, collectors, conveyors, ducts, sifters and storage bins.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 7 Agriculture 3 2013-01-01 2013-01-01 false Cleaning of dryers, collectors, conveyors, ducts, sifters and storage bins. 58.246 Section 58.246 Agriculture Regulations of the Department of Agriculture... Inspection and Grading Service 1 Operations and Operating Procedures § 58.246 Cleaning of dryers,...

  6. 7 CFR 58.246 - Cleaning of dryers, collectors, conveyors, ducts, sifters and storage bins.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 7 Agriculture 3 2014-01-01 2014-01-01 false Cleaning of dryers, collectors, conveyors, ducts, sifters and storage bins. 58.246 Section 58.246 Agriculture Regulations of the Department of Agriculture... Inspection and Grading Service 1 Operations and Operating Procedures § 58.246 Cleaning of dryers,...

  7. Microfabricated thermionic detector

    DOEpatents

    Lewis, Patrick R; Manginell, Ronald P; Wheeler, David R; Trudell, Daniel E

    2012-10-30

    A microfabricated TID comprises a microhotplate and a thermionic source disposed on the microhotplate. The microfabricated TID can provide high sensitivity and selectivity to nitrogen- and phosphorous-containing compounds and other compounds containing electronegative function groups. The microfabricated TID can be microfabricated with semiconductor-based materials. The microfabricated TID can be combined with a microfabricated separation column and used in microanalytical system for the rapid on-site detection of pesticides, chemical warfare agents, explosives, pharmaceuticals, and other organic compounds that contain nitrogen or phosphorus.

  8. Laser processes for precise microfabrication of magnetic disk-drive components

    NASA Astrophysics Data System (ADS)

    Tam, Andrew C.

    2000-11-01

    The technique of laser micro-processing has recently found several important and widespread applications in the manufacturing of disk-drive components. Examples provided here include the cleaning of surface contaminants, the formation of nano-bumps on disk surfaces for controlled surface texturing or for making glide height standards, and the micro-bending of magnetic head sliders for flight-height controls. Short-pulsed laser irradiation at suitable wavelength, fluence, and incidence direction can be used to clean off particulate and organic-film contaminants from surfaces of critical components, for example, the slider and the disk. Controlled disk texturing is needed to alleviate the problem of stiction which occurs when the disk stop spinning and the super smooth slider comes into stationary contact with the super smooth disk. A compact laser operating at high pulse repetition rate can be used to produce a low-stiction racetrack composed of typically a million nano-bumps. This can be done both for NiP/aluminum disks, or for glass disks. Single isolated bump with a specified height for providing height-standard can also be tailor-made. Very recently, we have developed a 'laser curvature adjust technique' and implemented it into production of magnetic head sliders. Here, microscopic adjustments of the curvature of air bearing surface of sliders can be produced by suitable laser scribing at the back side of the ceramic slider.

  9. Micro-fabricated Helmholtz coil featuring disposable microfluidic sample inserts for applications in nuclear magnetic resonance

    NASA Astrophysics Data System (ADS)

    Spengler, N.; Moazenzadeh, A.; Meier, R. Ch; Badilita, V.; Korvink, J. G.; Wallrabe, U.

    2014-03-01

    In this study, we report on a novel, multi-use, high-resolution NMR/MRI micro-detection probe for the screening of flat samples. It is based on a Helmholtz coil pair in the centre of the probe, built out of two 1.5 mm diameter wirebonded copper coils, resulting in a homogeneous distribution of the magnetic field. For liquids and suspensions, custom fabricated, disposable sample inserts are placed inside the pair and aligned automatically, preventing the sensor and the samples from contamination. The sensor was successfully tested in a 500 MHz (11.7 T) spectrometer where we achieved a linewidth of 1.79 Hz (3.58 ppb) of a water phantom. Nutation experiments revealed an overall B1-field uniformity of 92% (ratio in signal intensity at flip angles of 810°/90°), leading to a homogeneous excitation of concentration limited samples. To demonstrate the imaging capabilities of the detector, we acquired images of a solid and a liquid sample—of a piece of leaf, directly inserted into the probe and of a sample insert, filled with a suspension of 50 μm diameter polymer beads and deionized water, with in-plane resolutions of 20 × 20 μ m2 and 10 × 10 μ m2, respectively.

  10. Real-time thickness measurement of biological tissues using a microfabricated magnetically-driven lens actuator.

    PubMed

    Mansoor, Hadi; Zeng, Haishan; Chiao, Mu

    2011-08-01

    A fiber optic confocal catheter with a micro scanning lens was developed for real-time and non-contact thickness measurement of biological tissue. The catheter has an outer diameter and rigid length of 4.75 mm and 30 mm respectively and is suitable for endoscopic applications. The catheter incorporates a lens actuator that is fabricated using microelectromechanical systems (MEMS) technology. The lens is mounted on a folded flexure made of nickel and is actuated by magnetic field. Thickness measurements are performed by positioning the catheter in front of the tissue and actuating the lens scanner in the out-of-plane direction. A single-mode optical fiber (SMF) is used to deliver a 785 nm laser beam to the tissue and relay back the reflected light from the tissue to a photomultiplier tube (PMT). When the focal point of the scanning lens passes tissue boundaries, intensity peaks are detected in the reflecting signal. Tissue thickness is calculated using its index of refraction and the lens displacement between intensity peaks. The utility of the confocal catheter was demonstrated by measuring the cornea and skin thicknesses of a mouse. Measurement uncertainty of 8.86 µm within 95% confidence interval has been achieved. PMID:21468630

  11. Microfabricated Spin Polarized Atomic Magnetometers

    NASA Astrophysics Data System (ADS)

    Jimenez Martinez, Ricardo

    Spin polarized atomic magnetometers involve the preparation of atomic spins and their detection for monitoring magnetic fields. Due to the fact that magnetic fields are ubiquitous in our world, spin polarized atomic magnetometers are used in a wide range of applications from the detection of magnetic fields generated by the human heart and brain to the detection of nuclear magnetic resonance. In this thesis we developed microfabricated spin polarized atomic magnetometers. These sensors are based on optical pumping and spin-exchange collisions between alkali atoms and noble gases contained in microfabricated millimeter-scale vapor cells. In the first part of the thesis, we improved different features of current microfabricated optical magnetometers. Specifically, we improved the bandwidth of these devices, without degrading their magnetic field sensitivity, by broadening their magnetic resonance through spin-exchange collisions between alkali atoms. We also implemented all-optical excitation techniques to avoid problems, such as the magnetic perturbation of the environment, induced by the radio-frequency fields used in some of these sensors. In the second part of the thesis we demonstrated a microfluidic chip for the optical production and detection of hyperpolarized Xe gas through spin-exchange collisions with optically pumped Rb atoms. These devices are critical for the widespread use of spin polarized atomic magnetometers in applications requiring simple, compact, low-cost, and portable instrumentation.

  12. The CHAPS, SIFTER, and TAPS-R as Predictors of (C)AP Skills and (C)APD

    ERIC Educational Resources Information Center

    Wilson, Wayne J.; Jackson, Alison; Pender, Alice; Rose, Carla; Wilson, Jacqueline; Heine, Chyrisse; Khan, Asad

    2011-01-01

    Purpose: In this study, the authors investigated the relationships between 3 tests used to screen for (central) auditory processing disorder ([C]APD)--the Children's Auditory Performance Scale (CHAPS; W. J. Smoski, M. A. Brunt, & J. C. Tannahill, 1998), the Screening Instrument for Targeting Educational Risk (SIFTER; K. Anderson, 1989), and the…

  13. Microfabricated teeter-totter resonator

    DOEpatents

    Adkins, Douglas Ray; Heller, Edwin J.; Shul, Randy J.

    2004-11-23

    A microfabricated teeter-totter resonator comprises a frame, a paddle pivotably anchored to the frame by pivot arms that define an axis of rotation, a current conductor line on a surface of the paddle, means for applying a static magnetic field substantially perpendicular to the rotational axis and in the plane of the paddle, and means for energizing the current conductor line with an alternating current. A Lorentz force is generated by the interaction of the magnetic field with the current flowing in the conductor line, causing the paddle to oscillate about the axis of rotation. The teeter-totter resonator can be fabricated with micromachining techniques with materials used in the integrated circuits manufacturing industry. The microfabricated teeter-totter resonator has many varied applications, both as an actuation device and as a sensor. When used as a chemical sensor, a chemically sensitive coating can be disposed on one or both surfaces of the paddle to enhance the absorption of chemical analytes from a fluid stream. The resulting mass change can be detected as a change in the resonant frequency or phase of the oscillatory motion of the paddle.

  14. Microfabricated ion trap array

    DOEpatents

    Blain, Matthew G.; Fleming, James G.

    2006-12-26

    A microfabricated ion trap array, comprising a plurality of ion traps having an inner radius of order one micron, can be fabricated using surface micromachining techniques and materials known to the integrated circuits manufacturing and microelectromechanical systems industries. Micromachining methods enable batch fabrication, reduced manufacturing costs, dimensional and positional precision, and monolithic integration of massive arrays of ion traps with microscale ion generation and detection devices. Massive arraying enables the microscale ion traps to retain the resolution, sensitivity, and mass range advantages necessary for high chemical selectivity. The reduced electrode voltage enables integration of the microfabricated ion trap array with on-chip circuit-based rf operation and detection electronics (i.e., cell phone electronics). Therefore, the full performance advantages of the microfabricated ion trap array can be realized in truly field portable, handheld microanalysis systems.

  15. Microfabricated AC impedance sensor

    DOEpatents

    Krulevitch, Peter; Ackler, Harold D.; Becker, Frederick; Boser, Bernhard E.; Eldredge, Adam B.; Fuller, Christopher K.; Gascoyne, Peter R. C.; Hamilton, Julie K.; Swierkowski, Stefan P.; Wang, Xiao-Bo

    2002-01-01

    A microfabricated instrument for detecting and identifying cells and other particles based on alternating current (AC) impedance measurements. The microfabricated AC impedance sensor includes two critical elements: 1) a microfluidic chip, preferably of glass substrates, having at least one microchannel therein and with electrodes patterned on both substrates, and 2) electrical circuits that connect to the electrodes on the microfluidic chip and detect signals associated with particles traveling down the microchannels. These circuits enable multiple AC impedance measurements of individual particles at high throughput rates with sufficient resolution to identify different particle and cell types as appropriate for environmental detection and clinical diagnostic applications.

  16. Microfabricated diffusion source

    DOEpatents

    Oborny, Michael C.; Frye-Mason, Gregory C.; Manginell, Ronald P.

    2008-07-15

    A microfabricated diffusion source to provide for a controlled diffusion rate of a vapor comprises a porous reservoir formed in a substrate that can be filled with a liquid, a headspace cavity for evaporation of the vapor therein, a diffusion channel to provide a controlled diffusion of the vapor, and an outlet to release the vapor into a gas stream. The microfabricated diffusion source can provide a calibration standard for a microanalytical system. The microanalytical system with an integral diffusion source can be fabricated with microelectromechanical systems technologies.

  17. Micro-Fabrication and Circuit Optimization for Magnetic Components of High-Efficiency DC-DC Converters

    NASA Astrophysics Data System (ADS)

    Tian, Rui

    Magnetic components are essential parts of power converters. Inductors with magnetic cores are investigated. An eddy current loss model for pot-core inductors is developed with finite elemental analysis (FEA). The reliability of inductors using magnetic cores in a high-temperature environment is investigated. Working in up to 150°C circumstance for a short periods is not destructive for the inductors. Optimization of toroidal inductors in a DC-DC converter is investigated. Parasitic capacitance and the capacitive loss in toroidal inductors are modeled. Standard circuit optimization is performed to explore the energy conversion efficiency of the toroidal inductors. Thermal analysis, light-load efficiency and relative permeability of the toroidal inductor design are also investigated. The toroidal inductor can achieve about 85% efficiency for 3 A DC current and 1 W/mm2 power density. Inductor-only efficiency of toroidal inductors is investigated with revised model. At 100 MHz operating frequency, toroidal inductors can achieve more than 97% inductor efficiency with power density range of 0.7 W/mm2 to 6 W/mm2. The performance of our nanograngular magnetic core is dependent on the angle of the poling magnetic field compared to the field during operation. Experiments on a serious of samples show that the poling angle can deviate by up to 15 degrees from ideal with only a small penalty in performance. The field-angle experiment is intended to prove integrated toroidal inductor process possible. A magnetic fixture model is proposed for large-scale toroidal inductor processing.

  18. Program of research on microfabrication techniques for VLSI magnetic devices. Final report, 1 October 1983-30 September 1984

    SciTech Connect

    Kryder, M.H.; Alex, M.; Artman, J.; Bauer, L.; Campbell, R.

    1984-11-01

    New materials, new fabrication techniques and new device structures for high density magnetic bubble devices were developed. The main focus of the work has been to develop ion-implanted contiguous disk devices offering sixteen times the bit density of presently manufactured bubble devices and chip capacities of 64 Mbit. Under this contract, the authors developed a computer program for modeling magnetic bubble garnet materials and applied it to the design of bubble materials having isotropic magnetostriction. They have previously show that such materials would provide better device operating characteristics. During the past year they also modeled the anisotropic stresses around ion-implanted propagation patterns and showed how they produce nonuniform anisotropies due to magnetostrictive effects.

  19. Program of research on microfabrication techniques for vlsi magnetic devices. Interim progress report 30 Sep 1981-29 Sep 1982

    SciTech Connect

    Kryder, M.H.; Bauer, C.L.; Rayne, J.A.; Guzman, A.

    1982-10-01

    Means of fabricating, selectively modifying, and characterizing single crystal epitaxial garnet and amorphous magnetic thin films are being investigated with the intention of developing new materials and processes for magnetic devices including bubble, recording, magneto-optic, and micro-wave devices. Submicron ion unimplantable garnets have been developed for ion-implanted contiguous disk devices. A wideband ferromagnetic resonance spectrometer and a high resolution magneto-optic photometer were developed and used to measure the magneto-striction and crystalline anisotropy constants of these materials. It was found that ion implantation dramatically reduces the crystalline anisotropy field and that a large portion of the change in uniaxial anisotropy of garnets is produced by non-stress related mechanisms which became more important as bubble size is reduced. Transmission electron microscopy investigations of ion implanted garnets have revealed clearly observable changes in stress and structure produced by implantation. Amorphous magnetic materials have been developed which support submicrometer sized domains for bubble and magneto-optic device applications. A number of high density bubble devices have been designed and fabricated: 2-4 micrometers period ion-implanted contiguous disk devices, 4-8 micrometer period current-acessed devices, and 2-6 micrometer period current-accessed ion implanted devices with 4 to 16 times lower power dissipation than earlier current-accessed devices.

  20. Microfabricated particle focusing device

    DOEpatents

    Ravula, Surendra K.; Arrington, Christian L.; Sigman, Jennifer K.; Branch, Darren W.; Brener, Igal; Clem, Paul G.; James, Conrad D.; Hill, Martyn; Boltryk, Rosemary June

    2013-04-23

    A microfabricated particle focusing device comprises an acoustic portion to preconcentrate particles over large spatial dimensions into particle streams and a dielectrophoretic portion for finer particle focusing into single-file columns. The device can be used for high throughput assays for which it is necessary to isolate and investigate small bundles of particles and single particles.

  1. Microfabricated bragg waveguide

    DOEpatents

    Fleming, James G.; Lin, Shawn-Yu; Hadley, G. Ronald

    2004-10-19

    A microfabricated Bragg waveguide of semiconductor-compatible material having a hollow core and a multilayer dielectric cladding can be fabricated by integrated circuit technologies. The microfabricated Bragg waveguide can comprise a hollow channel waveguide or a hollow fiber. The Bragg fiber can be fabricated by coating a sacrificial mandrel or mold with alternating layers of high- and low-refractive-index dielectric materials and then removing the mandrel or mold to leave a hollow tube with a multilayer dielectric cladding. The Bragg channel waveguide can be fabricated by forming a trench embedded in a substrate and coating the inner wall of the trench with a multilayer dielectric cladding. The thicknesses of the alternating layers can be selected to satisfy the condition for minimum radiation loss of the guided wave.

  2. SIFTER: Scintillating Fiber Telescopes for Energetic Radiation, Gamma-Ray Applications

    NASA Technical Reports Server (NTRS)

    Paciesas, William S.

    2002-01-01

    The research project "SIFTER: Scintillating Fiber Telescopes for Energetic Radiation, Gamma-Ray Applications" approved under the NASA High Energy Astrophysics Research Program. The principal investigator of the proposal was Prof. Geoffrey N. Pendleton, who is currently on extended leave from UAH. Prof. William S. Paciesas administered the grant during Dr. Pendleton's absence. The project was originally funded for one year from 6/8/2000 to 6/7/2001. Due to conflicts with other commitments by the PI, the period of performance was extended at no additional cost until 6/30/2002. The goal of this project was to study scintillating fiber pair-tracking gamma-ray telescope configurations specifically designed to perform imaging and spectroscopy in the 5 - 250 MeV energy range. The main efforts were concentrated in two areas: 1) development of tracking techniques and event reconstruction algorithms, with particular emphasis on angular resolution; and 2) investigation of coded apertures as a means to improve the instrument angular resolution at low energies.

  3. Microfabricated Formaldehyde Gas Sensors

    PubMed Central

    Flueckiger, Jonas; Ko, Frank K.; Cheung, Karen C.

    2009-01-01

    Formaldehyde is a volatile organic compound that is widely used in textiles, paper, wood composites, and household materials. Formaldehyde will continuously outgas from manufactured wood products such as furniture, with adverse health effects resulting from prolonged low-level exposure. New, microfabricated sensors for formaldehyde have been developed to meet the need for portable, low-power gas detection. This paper reviews recent work including silicon microhotplates for metal oxide-based detection, enzyme-based electrochemical sensors, and nanowire-based sensors. This paper also investigates the promise of polymer-based sensors for low-temperature, low-power operation. PMID:22291561

  4. Microfabricated therapeutic actuators

    SciTech Connect

    Lee, Abraham P.; Northrup, M. Allen; Ciarlo, Dino R.; Krulevitch, Peter A.; Benett, William J.

    1999-01-01

    Microfabricated therapeutic actuators are fabricated using a shape memory polymer (SMP), a polyurethane-based material that undergoes a phase transformation at a specified temperature (Tg). At a temperature above temperature Tg material is soft and can be easily reshaped into another configuration. As the temperature is lowered below temperature Tg the new shape is fixed and locked in as long as the material stays below temperature Tg. Upon reheating the material to a temperature above Tg, the material will return to its original shape. By the use of such SMP material, SMP microtubing can be used as a release actuator for the delivery of embolic coils through catheters into aneurysms, for example. The microtubing can be manufactured in various sizes and the phase change temperature Tg is determinate for an intended temperature target and intended use.

  5. Microfabricated therapeutic actuators

    DOEpatents

    Lee, A.P.; Northrup, M.A.; Ciarlo, D.R.; Krulevitch, P.A.; Benett, W.J.

    1999-06-15

    Microfabricated therapeutic actuators are fabricated using a shape memory polymer (SMP), a polyurethane-based material that undergoes a phase transformation at a specified temperature (Tg). At a temperature above temperature Tg material is soft and can be easily reshaped into another configuration. As the temperature is lowered below temperature Tg the new shape is fixed and locked in as long as the material stays below temperature Tg. Upon reheating the material to a temperature above Tg, the material will return to its original shape. By the use of such SMP material, SMP microtubing can be used as a release actuator for the delivery of embolic coils through catheters into aneurysms, for example. The microtubing can be manufactured in various sizes and the phase change temperature Tg is determinate for an intended temperature target and intended use. 8 figs.

  6. Silicon microfabricated beam expander

    NASA Astrophysics Data System (ADS)

    Othman, A.; Ibrahim, M. N.; Hamzah, I. H.; Sulaiman, A. A.; Ain, M. F.

    2015-03-01

    The feasibility design and development methods of silicon microfabricated beam expander are described. Silicon bulk micromachining fabrication technology is used in producing features of the structure. A high-precision complex 3-D shape of the expander can be formed by exploiting the predictable anisotropic wet etching characteristics of single-crystal silicon in aqueous Potassium-Hydroxide (KOH) solution. The beam-expander consist of two elements, a micromachined silicon reflector chamber and micro-Fresnel zone plate. The micro-Fresnel element is patterned using lithographic methods. The reflector chamber element has a depth of 40 µm, a diameter of 15 mm and gold-coated surfaces. The impact on the depth, diameter of the chamber and absorption for improved performance are discussed.

  7. Microfabricated ion frequency standard

    DOEpatents

    Schwindt, Peter; Biedermann, Grant; Blain, Matthew G.; Stick, Daniel L.; Serkland, Darwin K.; Olsson, III, Roy H.

    2010-12-28

    A microfabricated ion frequency standard (i.e. an ion clock) is disclosed with a permanently-sealed vacuum package containing a source of ytterbium (Yb) ions and an octupole ion trap. The source of Yb ions is a micro-hotplate which generates Yb atoms which are then ionized by a ultraviolet light-emitting diode or a field-emission electron source. The octupole ion trap, which confines the Yb ions, is formed from suspended electrodes on a number of stacked-up substrates. A microwave source excites a ground-state transition frequency of the Yb ions, with a frequency-doubled vertical-external-cavity laser (VECSEL) then exciting the Yb ions up to an excited state to produce fluorescent light which is used to tune the microwave source to the ground-state transition frequency, with the microwave source providing a precise frequency output for the ion clock.

  8. Silicon microfabricated beam expander

    SciTech Connect

    Othman, A. Ibrahim, M. N.; Hamzah, I. H.; Sulaiman, A. A.; Ain, M. F.

    2015-03-30

    The feasibility design and development methods of silicon microfabricated beam expander are described. Silicon bulk micromachining fabrication technology is used in producing features of the structure. A high-precision complex 3-D shape of the expander can be formed by exploiting the predictable anisotropic wet etching characteristics of single-crystal silicon in aqueous Potassium-Hydroxide (KOH) solution. The beam-expander consist of two elements, a micromachined silicon reflector chamber and micro-Fresnel zone plate. The micro-Fresnel element is patterned using lithographic methods. The reflector chamber element has a depth of 40 µm, a diameter of 15 mm and gold-coated surfaces. The impact on the depth, diameter of the chamber and absorption for improved performance are discussed.

  9. Microfabricated triggered vacuum switch

    DOEpatents

    Roesler, Alexander W.; Schare, Joshua M.; Bunch, Kyle

    2010-05-11

    A microfabricated vacuum switch is disclosed which includes a substrate upon which an anode, cathode and trigger electrode are located. A cover is sealed over the substrate under vacuum to complete the vacuum switch. In some embodiments of the present invention, a metal cover can be used in place of the trigger electrode on the substrate. Materials used for the vacuum switch are compatible with high vacuum, relatively high temperature processing. These materials include molybdenum, niobium, copper, tungsten, aluminum and alloys thereof for the anode and cathode. Carbon in the form of graphitic carbon, a diamond-like material, or carbon nanotubes can be used in the trigger electrode. Channels can be optionally formed in the substrate to mitigate against surface breakdown.

  10. Microfabricated High-Moment Micrometer-sized MRI Contrast Agents

    PubMed Central

    Zabow, Gary; Dodd, Stephen J.; Shapiro, Erik; Moreland, John; Koretsky, Alan P.

    2010-01-01

    While chemically synthesized superparamagnetic microparticles have enabled much new research based on MRI-tracking of magnetically labeled cells, signal-to-noise levels still limit the potential range of applications. Here it is shown how, through top-down microfabrication, contrast agent relaxivity can be increased several-fold, which should extend the sensitivity of such cell tracking studies. Microfabricated agents can benefit from both higher magnetic moments and higher uniformity than their chemically synthesized counterparts, implying increased label visibility and more quantitative image analyses. To assess the performance of microfabricated micrometer-sized contrast agent particles, analytic models and numerical simulations are developed and tested against new microfabricated agents described in this paper, as well as against results of previous imaging studies of traditional chemically synthesized microparticle agents. Experimental data showing signal effects of 500-nanometer thick, 2-micrometer diameter, gold-coated iron and gold-coated nickel disks verify the simulations. Additionally, it is suggested that measures of location better than the pixel resolution can be obtained and that these are aided using well-defined contrast agent particles achievable through microfabrication techniques. PMID:20928829

  11. Implantation of microfabricated immunoisolating biocapsules

    NASA Astrophysics Data System (ADS)

    Desai, Tejal A.; Chu, Wen Hwa; Ferrari, Mauro; Rasi, Guido; Sinibaldi-Vallebona, Paola; Borboni, Patrizia; Beattie, G.; Hayek, A.

    1998-03-01

    Silicon-based biocapsules have been microfabricated with uniform and well-controlled pore dimensions in the tens of nanometer range to provide effective immunoisolation of cell xenografts. Surface and bulk micromachining were integrated in the fabrication process, resulting in a diffusion membrane with mechanical and chemical stability, surrounded by an anisotropically-etched silicon wafer, which serves as the encapsulation cavity. The membrane allows the diffusion of essential nutrients while blocking the passage of immune molecules, which may destroy cellular transplants. Preliminary short term studies on both primary pancreatic islets and insulinoma cell lines encapsulated within microfabricated biocapsules were conducted to determine the toxicity and biocompatibility of biocapsules, the viability and functionality of encapsulated cells, as well as the overall immunoprotective capabilities of the biocapsule. Results seem to indicate that microfabricated biocapsules are non-toxic and do not elicit any adverse inflammatory reactions when implanted. Furthermore, encapsulated insulinoma cells remained viable and functional within microfabricated environments in vivo. These results show the feasibility and potential application of microfabricated biocapsules for several pathologies.

  12. Microfabricated Genomic Analysis System

    NASA Technical Reports Server (NTRS)

    Gonda, Steve; Elms, Rene

    2005-01-01

    Genetic sequencing and many genetic tests and assays require electrophoretic separation of DNA. In this technique, DNA fragments are separated by size as they migrate through a sieving gel under the influence of an applied electric field. In order to conduct these analyses on-orbit, it is essential to acquire the capability to efficiently perform electrophoresis in a microgravity environment. Conventional bench top electrophoresis equipment is large and cumbersome and does not lead itself to on-orbit utilization. Much of the previous research regarding on-orbit electrophoresis involved altering conventional electrophoresis equipment for bioprocessing, purification, and/or separation technology applications. A new and more efficient approach to on-orbit electrophoresis is the use of a microfabricated electrophoresis platform. These platforms are much smaller, less expensive to produce and operate, use less power, require smaller sample sizes (nanoliters), and achieve separation in a much shorter distance (a few centimeters instead of 10 s or 100 s of centimeters.) In contrast to previous applications, this platform would be utilized as an analytical tool for life science/medical research, environmental monitoring, and medical diagnoses. Identification of infectious agents as well as radiation related damage are significant to NASA s efforts to maintain, study, and monitor crew health during and in support of near-Earth and interplanetary missions. The capability to perform genetic assays on-orbit is imperative to conduct relevant and insightful biological and medical research, as well as continuing NASA s search for life elsewhere. This technology would provide an essential analytical tool for research conducted in a microgravity environment (Shuttle, ISS, long duration/interplanetary missions.) In addition, this technology could serve as a critical and invaluable component of a biosentinel system to monitor space environment genotoxic insults to include radiation.

  13. Microfabrication using soft lithography

    NASA Astrophysics Data System (ADS)

    Zhao, Xiao-Mei

    Soft Lithography is a group of non-photolithographic techniques currently being explored in our group. Four such techniques-microcontact printing (μCP), replica molding (REM), micromolding in capillaries (MIMIC), and microtransfer molding (μTM)-have been demonstrated for fabricating micro- and nanostructures of a variety of materials with dimension >=30 nm. Part I (Chapters 1-5) reviews several aspects of the three molding techniques REM, MIMIC, and μTM. Chapters 1-3 describe μTM and MIMIC, and the use of these techniques in the fabrication of functional devices. μTM is capable of generating μm-scale structures over large areas, on both planar and contoured surfaces, and is able to make 3-dimensional structures layer by layer. The capability of μTM and MIMIC has been demonstrated in the fabrication of single-mode waveguides, waveguide couplers and interferometers. The coupling between waveguides can be tailored by waveguide spacing or the differential in curing time between the waveguides and the cladding. Chapters 4-5 demonstrate the combination of REM and shrinkable polystyrene (PS) films to reduce the feature size of microstructures and to generate microstructures with high aspect ratios on both planar and curved surfaces. A shrinkable PS film is patterned with relief structures, and then heated and shrinks. Thermal shrinkage results in a 100-fold increase in the aspect ratio of the patterned microstructures in the PS film. The microstructures in the shrunken PS films can be transferred to many other materials by REM. Part II (Chapters 6-7) focuses on two issues in the microfabrication using self-assembled monolayers (SAMs) as ultrathin resists. Chapter 6 describes a selective etching solution for transferring patterns of SAMs of alkanethiolates into the underlying layers (e.g., gold, silver, and copper). This etching solution uses thiosulfate as the ligand that coordinates to the metal ions, and ferricyanide as the oxidant. It has been demonstrated to be

  14. Microfabricated Optically-Pumped Magnetometers for Biomagnetic Applications

    NASA Astrophysics Data System (ADS)

    Knappe, Svenja; Alem, Orang; Sheng, Dong; Kitching, John

    2016-06-01

    We report on the progress in developing microfabricated optically-pumped magnetometer arrays for imaging applications. We have improved our sensitivities by several orders of magnitude in the last ten years. Now, our zero-field magnetometers reach noise values below 15 fT/Hz1/2. Recently, we have also developed gradiometers to reject ambient magnetic field noise. We have built several imaging arrays and validated them for biomedical measurements of brain and heart activity.

  15. Infrared microthermography of microfabricated devices

    NASA Astrophysics Data System (ADS)

    Furstenberg, Robert; Kendziora, C. A.; Stepnowski, Stanley V.; McGill, R. Andrew

    2007-06-01

    We report a new experimental apparatus for infrared microthermography applicable to a wide class of samples including semitransparent ones and perforated devices. This setup is particularly well suited for the thermography of microfabricated devices. Traditionally, temperature calibration is performed using calibration hot plates, but this is not applicable to transmissive samples. In this work a custom designed miniature calibration oven in conjunction with spatial filtering is used to obtain accurate static and transient temperature maps of actively heated devices. The procedure does not require prior knowledge of the emissivity. Calibration and image processing algorithms are discussed and analyzed. We show that relatively inexpensive uncooled bolometer arrays can be a suitable detector choice in certain radiometric applications. As an example, we apply this method in the analysis of temperature profiles of an actively heated microfabricated preconcentrator device that incorporates a perforated membrane and is used in trace detection of illicit substances.

  16. Infrared microthermography of microfabricated devices

    SciTech Connect

    Furstenberg, Robert; Kendziora, C. A.; Stepnowski, Stanley V.; McGill, R. Andrew

    2007-06-15

    We report a new experimental apparatus for infrared microthermography applicable to a wide class of samples including semitransparent ones and perforated devices. This setup is particularly well suited for the thermography of microfabricated devices. Traditionally, temperature calibration is performed using calibration hot plates, but this is not applicable to transmissive samples. In this work a custom designed miniature calibration oven in conjunction with spatial filtering is used to obtain accurate static and transient temperature maps of actively heated devices. The procedure does not require prior knowledge of the emissivity. Calibration and image processing algorithms are discussed and analyzed. We show that relatively inexpensive uncooled bolometer arrays can be a suitable detector choice in certain radiometric applications. As an example, we apply this method in the analysis of temperature profiles of an actively heated microfabricated preconcentrator device that incorporates a perforated membrane and is used in trace detection of illicit substances.

  17. Infrared microthermography of microfabricated devices.

    PubMed

    Furstenberg, Robert; Kendziora, C A; Stepnowski, Stanley V; McGill, R Andrew

    2007-06-01

    We report a new experimental apparatus for infrared microthermography applicable to a wide class of samples including semitransparent ones and perforated devices. This setup is particularly well suited for the thermography of microfabricated devices. Traditionally, temperature calibration is performed using calibration hot plates, but this is not applicable to transmissive samples. In this work a custom designed miniature calibration oven in conjunction with spatial filtering is used to obtain accurate static and transient temperature maps of actively heated devices. The procedure does not require prior knowledge of the emissivity. Calibration and image processing algorithms are discussed and analyzed. We show that relatively inexpensive uncooled bolometer arrays can be a suitable detector choice in certain radiometric applications. As an example, we apply this method in the analysis of temperature profiles of an actively heated microfabricated preconcentrator device that incorporates a perforated membrane and is used in trace detection of illicit substances. PMID:17614631

  18. Microfabricated injectable drug delivery system

    DOEpatents

    Krulevitch, Peter A.; Wang, Amy W.

    2002-01-01

    A microfabricated, fully integrated drug delivery system capable of secreting controlled dosages of multiple drugs over long periods of time (up to a year). The device includes a long and narrow shaped implant with a sharp leading edge for implantation under the skin of a human in a manner analogous to a sliver. The implant includes: 1) one or more micromachined, integrated, zero power, high and constant pressure generating osmotic engine; 2) low power addressable one-shot shape memory polymer (SMP) valves for switching on the osmotic engine, and for opening drug outlet ports; 3) microfabricated polymer pistons for isolating the pressure source from drug-filled microchannels; 4) multiple drug/multiple dosage capacity, and 5) anisotropically-etched, atomically-sharp silicon leading edge for penetrating the skin during implantation. The device includes an externally mounted controller for controlling on-board electronics which activates the SMP microvalves, etc. of the implant.

  19. Temperature programmable microfabricated gas chromatography column

    DOEpatents

    Manginell, Ronald P.; Frye-Mason, Gregory C.

    2003-12-23

    A temperature programmable microfabricated gas chromatography column enables more efficient chemical separation of chemical analytes in a gas mixture by the integration of a resistive heating element and temperature sensing on the microfabricated column. Additionally, means are provided to thermally isolate the heated column from their surroundings. The small heat capacity and thermal isolation of the microfabricated column improves the thermal time response and power consumption, both important factors for portable microanalytical systems.

  20. Microfabricated fuel heating value monitoring device

    DOEpatents

    Robinson, Alex L.; Manginell, Ronald P.; Moorman, Matthew W.

    2010-05-04

    A microfabricated fuel heating value monitoring device comprises a microfabricated gas chromatography column in combination with a catalytic microcalorimeter. The microcalorimeter can comprise a reference thermal conductivity sensor to provide diagnostics and surety. Using microfabrication techniques, the device can be manufactured in production quantities at a low per-unit cost. The microfabricated fuel heating value monitoring device enables continuous calorimetric determination of the heating value of natural gas with a 1 minute analysis time and 1.5 minute cycle time using air as a carrier gas. This device has applications in remote natural gas mining stations, pipeline switching and metering stations, turbine generators, and other industrial user sites. For gas pipelines, the device can improve gas quality during transfer and blending, and provide accurate financial accounting. For industrial end users, the device can provide continuous feedback of physical gas properties to improve combustion efficiency during use.

  1. DNA electrophoresis in microfabricated devices

    NASA Astrophysics Data System (ADS)

    Dorfman, Kevin D.

    2010-10-01

    Picking up at the conclusion of Viovy’s review of the physics of gel electrophoresis [J.-L. Viovy, Rev. Mod. Phys. 72, 813 (2000)10.1103/RevModPhys.72.813], this review synthesizes the experimental data, theoretical models, and simulation results for DNA electrophoresis in microfabricated and nanofabricated devices appearing since the seminal paper by Volkmuth and Austin [Nature (London) 358, 600 (1992)10.1038/358600a0]. Prototype versions of these devices separate DNA by molecular weight at a rate far superior to gel electrophoresis. After providing an overview of the requisite background material in polymer physics, electrophoresis, and microfluidic device fabrication, the focus is on the following three generic problems: (i) collision with an isolated post, (ii) transport in an array of posts, and (iii) entropic trapping and filtration in the slit-well motif. The transport phenomena are examined here in the context of the length and time scales characterizing the DNA, the device, and the applied electric field.

  2. Microfabrication techniques for semiconductor lasers

    NASA Astrophysics Data System (ADS)

    Tamanuki, Takemasa; Tadokoro, T.; Morito, Ken; Koyama, Fumio; Iga, Kenichi

    1991-03-01

    Several important techniques for fabricating micro-cavity semiconductor lasers including surface emitting lasers have been developed. Reactive ion beam etch (RIBE) for GaA1As and GaInAsP is employed and its condition for vertical fine etch under low damages and removal of residual damages are made clear. Passivation by sulfur is introduced to the fabrication process. Regrowth techniques for DII structures by LPE and MOCVD has been established. Some device applications are discussed. 1. MICRO-ETCHING PROCESS Micro-cavity lasers including a vertical cavity surface emitting laser1 are attracting the research interest for optical parallel processing and parallel light wave systems. In order to realize micron-order or sub-micron laserdevices the technology of micro-fabrication must be established. In this study the total fabrication technology has been almost completed. First fine and low damage etching condition by ultrahigh vacuum background RIBE using a Cl2 gas has been made clear. We have found an isotropic etching condition for the vertical side wall formation and good mask traceability i. e. the acceleration voltage is 500 V and substrate temperature is 150 C with a 5000A thickness Si02 mask. Residual damages induced on the surface and the side wall are characterized by photo-luminescence and making stripe lasers. Figure 1 is the histogram of the nominal threshold current density for (a) oxide-defined stripe lasers (b) RIBE etched and LPE regrown BH-lasers using an LPE grown DII wafer (LPE/LPE) and (c) RIBE etched

  3. Microfabricated environments to study collective cell behaviors.

    PubMed

    Vedula, Sri Ram Krishna; Ravasio, Andrea; Anon, Ester; Chen, Tianchi; Peyret, Grégoire; Ashraf, Mohammed; Ladoux, Benoit

    2014-01-01

    Coordinated cell movements in epithelial layers are essential for proper tissue morphogenesis and homeostasis. Microfabrication techniques have proven to be very useful for studies of collective cell migration in vitro. In this chapter, we briefly review the use of microfabricated substrates in providing new insights into collective cell behaviors. We first describe the development of micropatterned substrates to study the influence of geometrical constraints on cell migration and coordinated movements. Then, we present an alternative method based on microfabricated pillar substrates to create well-defined gaps within cell sheets and study gap closure. We also provide a discussion that presents possible pitfalls and sheds light onto the important parameters that allow the study of long-term cell culture on substrates of well-defined geometries. PMID:24484669

  4. Processing Nanostructured Sensors Using Microfabrication Techniques

    NASA Technical Reports Server (NTRS)

    Hunter, Gary W.; VanderWal, Randall L.; Evans, Laura J.; Xu, Jennifer C.

    2010-01-01

    Standard microfabrication techniques can be implemented and scaled to help assemble nanoscale microsensors. Currently nanostructures are often deposited onto materials primarily by adding them to a solution, then applying the solution in a thin film. This results in random placement of the nanostructures with no controlled order, and no way to accurately reproduce the placement. This method changes the means by which microsensors with nanostructures are fabricated. The fundamental advantage to this approach is that it enables standard microfabrication techniques to be applied in the repeated manufacture of nanostructured sensors on a microplatform.

  5. Microfabricated pressure and shear stress sensors

    NASA Technical Reports Server (NTRS)

    Liu, Chang (Inventor); Chen, Jack (Inventor); Engel, Jonathan (Inventor)

    2009-01-01

    A microfabricated pressure sensor. The pressure sensor comprises a raised diaphragm disposed on a substrate. The diaphragm is configured to bend in response to an applied pressure difference. A strain gauge of a conductive material is coupled to a surface of the raised diaphragm and to at least one of the substrate and a piece rigidly connected to the substrate.

  6. Microfabricated field calibration assembly for analytical instruments

    DOEpatents

    Robinson, Alex L.; Manginell, Ronald P.; Moorman, Matthew W.; Rodacy, Philip J.; Simonson, Robert J.

    2011-03-29

    A microfabricated field calibration assembly for use in calibrating analytical instruments and sensor systems. The assembly comprises a circuit board comprising one or more resistively heatable microbridge elements, an interface device that enables addressable heating of the microbridge elements, and, in some embodiments, a means for positioning the circuit board within an inlet structure of an analytical instrument or sensor system.

  7. Processing of Nanostructured Devices Using Microfabrication Techniques

    NASA Technical Reports Server (NTRS)

    Hunter, Gary W (Inventor); Xu, Jennifer C (Inventor); Evans, Laura J (Inventor); Kulis, Michael H (Inventor); Berger, Gordon M (Inventor); Vander Wal, Randall L (Inventor)

    2014-01-01

    Systems and methods that incorporate nanostructures into microdevices are discussed herein. These systems and methods can allow for standard microfabrication techniques to be extended to the field of nanotechnology. Sensors incorporating nanostructures can be fabricated as described herein, and can be used to reliably detect a range of gases with high response.

  8. Microfabrication Technologies for Oral Drug Delivery

    PubMed Central

    Sant, Shilpa; Tao, Sarah L.; Fisher, Omar; Xu, Qiaobing; Peppas, Nicholas A.; Khademhosseini, Ali

    2012-01-01

    Micro-/nanoscale technologies such as lithographic techniques and microfluidics offer promising avenues to revolutionalize the fields of tissue engineering, drug discovery, diagnostics and personalized medicine. Microfabrication techniques are being explored for drug delivery applications due to their ability to combine several features such as precise shape and size into a single drug delivery vehicle. They also offer to create unique asymmetrical features incorporated into single or multiple reservoir systems maximizing contact area with the intestinal lining. Combined with intelligent materials, such microfabricated platforms can be designed to be bioadhesive and stimuli-responsive. Apart from drug delivery devices, microfabrication technologies offer exciting opportunities to create biomimetic gastrointestinal tract models incorporating physiological cell types, flow patterns and brush-border like structures. Here we review the recent developments in this field with a focus on the applications of microfabrication in the development of oral drug delivery devices and biomimetic gastrointestinal tract models that can be used to evaluate the drug delivery efficacy. PMID:22166590

  9. Micro-fabrication Techniques for Target Components

    SciTech Connect

    Miles, R; Hamilton, J; Crawford, J; Ratti, S; Trevino, J; Graff, T; Stockton, C; Harvey, C

    2008-06-10

    Micro-fabrication techniques, derived from the semi-conductor industry, can be used to make a variety of useful mechanical components for targets. A selection of these components including supporting cooling arms for prototype cryogenic inertial confinement fusion targets, stepped and graded density targets for materials dynamics experiments are described. Micro-fabrication enables cost-effective, simultaneous fabrication of multiple high-precision components with complex geometries. Micro-fabrication techniques such as thin-film deposition, photo-lithographic patterning and etch processes normally used in the semi-conductor manufacture industry, can be exploited to make useful mechanical target components. Micro-fabrication processes have in recent years been used to create a number of micro-electro-mechanical systems (MEMS) components such as pressure sensors, accelerometers, ink jet printer heads, microfluidics platforms and the like. These techniques consist primarily of deposition of thin films of material, photo-lithographic patterning and etching processes performed sequentially to produce three dimensional structures using essentially planar processes. While the planar technology can be limiting in terms of the possible geometries of the final product, advantages of using these techniques include the ability to make multiple complex structures simultaneously and cost-effectively. Target components fabricated using these techniques include the supporting cooling arms for cryogenic prototype fusion ignition targets, stepped targets for equation-of-state experiments, and graded density reservoirs for material strength experiments.

  10. Microfabricated mirrors for space applications

    NASA Astrophysics Data System (ADS)

    Bayat, Dara; Ataman, Caglar; Guldimann, Benedikt; Lani, Sébastien; Noell, Wilfried; de Rooij, Nico

    2011-03-01

    We report on the advances towards the design and fabrication of a system consisting of two 10mm mirrors, one actuated magnetically and the other electrostatically. The system will be used for beam steering. The maximum resonant frequencies and deflection angle of each of the actuators will be reviewed and compared.

  11. Optical pumping in a microfabricated Rb vapor cell using a microfabricated Rb discharge light source

    SciTech Connect

    Venkatraman, V.; Kang, S.; Affolderbach, C.; Mileti, G.; Shea, H.

    2014-02-03

    Miniature (microfabricated alkali vapor resonance cell using (1) a microfabricated Rb discharge lamp light source, as well as (2) a conventional glass-blown Rb discharge lamp. The microfabricated Rb lamp cell is a dielectric barrier discharge (DBD) light source, having the same inner cell volume of around 40 mm{sup 3} as that of the resonance cell, both filled with suitable buffer gases. A miniature (∼2 cm{sup 3} volume) test setup based on the M{sub z} magnetometer interrogation technique was used for observation of optical-radiofrequency double-resonance signals, proving the suitability of the microfabricated discharge lamp to introduce efficient optical pumping. The pumping ability of this light source was found to be comparable to or even better than that of a conventional glass-blown lamp. The reported results indicate that the micro-fabricated DBD discharge lamp has a high potential for the development of a new class of miniature atomic clocks, magnetometers, and quantum sensors.

  12. Microfabricated bulk wave acoustic bandgap device

    DOEpatents

    Olsson, Roy H.; El-Kady, Ihab F.; McCormick, Frederick; Fleming, James G.; Fleming, Carol

    2010-06-08

    A microfabricated bulk wave acoustic bandgap device comprises a periodic two-dimensional array of scatterers embedded within the matrix material membrane, wherein the scatterer material has a density and/or elastic constant that is different than the matrix material and wherein the periodicity of the array causes destructive interference of the acoustic wave within an acoustic bandgap. The membrane can be suspended above a substrate by an air or vacuum gap to provide acoustic isolation from the substrate. The device can be fabricated using microelectromechanical systems (MEMS) technologies. Such microfabricated bulk wave phononic bandgap devices are useful for acoustic isolation in the ultrasonic, VHF, or UHF regime (i.e., frequencies of order 1 MHz to 10 GHz and higher, and lattice constants of order 100 .mu.m or less).

  13. Microfabricated bulk wave acoustic bandgap device

    DOEpatents

    Olsson, Roy H.; El-Kady, Ihab F.; McCormick, Frederick; Fleming, James G.; Fleming, legal representative, Carol

    2010-11-23

    A microfabricated bulk wave acoustic bandgap device comprises a periodic two-dimensional array of scatterers embedded within the matrix material membrane, wherein the scatterer material has a density and/or elastic constant that is different than the matrix material and wherein the periodicity of the array causes destructive interference of the acoustic wave within an acoustic bandgap. The membrane can be suspended above a substrate by an air or vacuum gap to provide acoustic isolation from the substrate. The device can be fabricated using microelectromechanical systems (MEMS) technologies. Such microfabricated bulk wave phononic bandgap devices are useful for acoustic isolation in the ultrasonic, VHF, or UHF regime (i.e., frequencies of order 1 MHz to 10 GHz and higher, and lattice constants of order 100 .mu.m or less).

  14. Trapping of branched DNA in microfabricated structures.

    PubMed Central

    Volkmuth, W D; Duke, T; Austin, R H; Cox, E C

    1995-01-01

    We have observed electrostatic trapping of tribranched DNA molecules undergoing electrophoresis in a microfabricated pseudo-two-dimensional array of posts. Trapping occurs in a unique transport regimen in which the electrophoretic mobility is extremely sensitive to polymer topology. The arrest of branched polymers is explained by considering their center-of-mass motion; in certain conformations, owing to the constraints imposed by the obstacles a molecule cannot advance without the center of mass first moving a short distance backwards. The depth of the resulting local potential well can be much greater than the thermal energy so that escape of an immobilized molecule can be extremely slow. We summarize the expected behavior of the mobility as a function of field strength and topology and point out that the microfabricated arrays are highly suitable for detecting an extremely small number of branched molecules in a very large population of linear molecules. Images Fig. 2 PMID:7624337

  15. Enabling Systems Biology Approaches Through Microfabricated Systems

    PubMed Central

    Zhan, Mei; Chingozha, Loice; Lu, Hang

    2014-01-01

    With the experimental tools and knowledge that have accrued from a long history of reductionist biology, we can now start to put the pieces together and begin to understand how biological systems function as an integrated whole. Here, we describe how microfabricated tools have demonstrated promise in addressing experimental challenges in throughput, resolution and sensitivity to support systems-based approaches to biological understanding. PMID:23984862

  16. Optical properties of fluids in microfabricated channels

    SciTech Connect

    French, T.; Gourley, P.L.; McDonald, A.E.

    1997-03-01

    Microfabricated channels are widely thought to be the key to realizing chemical analysis on a microscopic scale. Chemical and biological information in the microchannels is often probed with optical techniques such as fluorescence, Raman and absorption spectroscopy. However, the optical effects of a microchannel are not well characterized. For example, it is important to understand the optics of the channel in order to optimize optical coupling efficiency. The authors consider various designs for enhancing the sensitivity of fluorescence detection in a microchannel.

  17. Evaluation of microfabricated deformable mirror systems

    NASA Astrophysics Data System (ADS)

    Cowan, William D.; Lee, Max K.; Bright, Victor M.; Welsh, Byron M.

    1998-09-01

    This paper presents recent result for aberration correction and beam steering experiments using polysilicon surface micromachined piston micromirror arrays. Microfabricated deformable mirrors offer a substantial cost reduction for adaptive optic systems. In addition to the reduced mirror cost, microfabricated mirrors typically require low control voltages, thus eliminating high voltage amplifiers. The greatly reduced cost per channel of adaptive optic systems employing microfabricated deformable mirrors promise high order aberration correction at low cost. Arrays of piston micromirrors with 128 active elements were tested. Mirror elements are on a 203 micrometers 12 by 12 square grid. The overall array size is 2.4 mm square. The arrays were fabricated in the commercially available DARPA supported MUMPs surface micromachining foundry process. The cost per mirror array in this prototyping process is less than 200 dollars. Experimental results are presented for a hybrid correcting element comprised of a lenslet array and piston micromirror array, and for a piston micromirror array only. Also presented is a novel digital deflection micromirror which requires no digital to analog converters, further reducing the cost of adaptive optics system.

  18. Integration of micro-fabricated atomic magnetometers on military systems

    NASA Astrophysics Data System (ADS)

    Schultz, Gregory; Mhaskar, Rahul; Prouty, Mark; Miller, Jonathan

    2016-05-01

    A new generation of ultra-high sensitivity magnetic sensors based on innovative micro-electromechanical systems (MEMS) are being developed and incorporated into military systems. Specifically, we are currently working to fully integrate the latest generation of MicroFabricated Atomic Magnetometers (MFAMs) developed by Geometrics on defense mobility systems such as unmanned systems, military vehicles and handheld units. Recent reductions in size, weight, and power of these sensors has enabled new deployment opportunities for improved sensitivity to targets of interest, but has also introduced new challenges associated with noise mitigation, mission configuration planning, and data processing. Our work is focused on overcoming the practical aspects of integrating these sensors with various military platforms. Implications associated with utilizing these combined sensor systems in working environments are addressed in order to optimize signal-to-noise ratios, detection probabilities, and false alarm mitigation. Specifically, we present collaborative work that bridges the gap between commercial specialists and operation platform integration organizations including magnetic signature characterization and mitigation as well as the development of simulation tools that consider a wide array of sensor, environmental, platform, and mission-level parameters. We discuss unique deployment concepts for explosive hazard target geolocation, and data processing. Applications include configurations for undersea and underground threat detection - particularly those associated with stationary or mobile explosives and compact metallic targets such as munitions, subsea threats, and other hazardous objects. We show the potential of current and future features of miniaturized magnetic sensors including very high magnetic field sensitivities, bandwidth selectivity, and array processing.

  19. Trends in Microfabrication Capabilities & Device Architectures.

    SciTech Connect

    Bauer, Todd; Jones, Adam; Lentine, Anthony L.; Mudrick, John; Okandan, Murat; Rodrigues, Arun F.

    2015-06-01

    The last two decades have seen an explosion in worldwide R&D, enabling fundamentally new capabilities while at the same time changing the international technology landscape. The advent of technologies for continued miniaturization and electronics feature size reduction, and for architectural innovations, will have many technical, economic, and national security implications. It is important to anticipate possible microelectronics development directions and their implications on US national interests. This report forecasts and assesses trends and directions for several potentially disruptive microfabrication capabilities and device architectures that may emerge in the next 5-10 years.

  20. Microfabricated electromagnetic filters for millikelvin experiments

    NASA Astrophysics Data System (ADS)

    le Sueur, Hélène; Joyez, Philippe

    2006-11-01

    In this article we report on the design, fabrication, and tests of microfabricated broadband filters suitable for proper electromagnetic thermalization of electrical lines connected to sensitive quantum electronics experiments performed at dilution fridge temperatures. Compared to previous such miniature filters, the new design improves on performance and reliability. These filters can be packed in space-saving cases with either single or multicontact connector. Measured performance in the accessible range compares well to simulations. We use these simulations to discuss the effectiveness of these filters for electromagnetic thermalization at 30mK.

  1. Microfabricated linear Paul-Straubel ion trap

    DOEpatents

    Mangan, Michael A.; Blain, Matthew G.; Tigges, Chris P.; Linker, Kevin L.

    2011-04-19

    An array of microfabricated linear Paul-Straubel ion traps can be used for mass spectrometric applications. Each ion trap comprises two parallel inner RF electrodes and two parallel outer DC control electrodes symmetric about a central trap axis and suspended over an opening in a substrate. Neighboring ion traps in the array can share a common outer DC control electrode. The ions confined transversely by an RF quadrupole electric field potential well on the ion trap axis. The array can trap a wide array of ions.

  2. Microfabricated microengine with constant rotation rate

    DOEpatents

    Romero, Louis A.; Dickey, Fred M.

    1999-01-01

    A microengine uses two synchronized linear actuators as a power source and converts oscillatory motion from the actuators into constant rotational motion via direct linkage connection to an output gear or wheel. The microengine provides output in the form of a continuously rotating output gear that is capable of delivering drive torque at a constant rotation to a micromechanism. The output gear can have gear teeth on its outer perimeter for directly contacting a micromechanism requiring mechanical power. The gear is retained by a retaining means which allows said gear to rotate freely. The microengine is microfabricated of polysilicon on one wafer using surface micromachining batch fabrication.

  3. Microfabrication of hybrid fluid membrane for microengines

    NASA Astrophysics Data System (ADS)

    Chutani, R.; Formosa, F.; de Labachelerie, M.; Badel, A.; Lanzetta, F.

    2015-12-01

    This paper describes the microfabrication and dynamic characterization of thick membranes providing a technological solution for microengines. The studied membranes are called hybrid fluid-membrane (HFM) and consist of two thin membranes that encapsulate an incompressible fluid. This work details the microelectromechanical system (MEMS) scalable fabrication and characterization of HFMs. The membranes are composite structures based on Silicon spiral springs embedded in a polymer (RTV silicone). The anodic bonding of multiple stacks of Si/glass structures, the fluid filling and the sealing have been demonstrated. Various HFMs were successfully fabricated and their dynamic characterization demonstrates the agreement between experimental and theoretical results.

  4. Microfabricated structures for integrated DNA analysis.

    PubMed Central

    Burns, M A; Mastrangelo, C H; Sammarco, T S; Man, F P; Webster, J R; Johnsons, B N; Foerster, B; Jones, D; Fields, Y; Kaiser, A R; Burke, D T

    1996-01-01

    Photolithographic micromachining of silicon is a candidate technology for the construction of high-throughput DNA analysis devices. However, the development of complex silicon microfabricated systems has been hindered in part by the lack of a simple, versatile pumping method for integrating individual components. Here we describe a surface-tension-based pump able to move discrete nanoliter drops through enclosed channels using only local heating. This thermocapillary pump can accurately mix, measure, and divide drops by simple electronic control. In addition, we have constructed thermal-cycling chambers, gel electrophoresis channels, and radiolabeled DNA detectors that are compatible with the fabrication of thermocapillary pump channels. Since all of the components are made by conventional photolithographic techniques, they can be assembled into more complex integrated systems. The combination of pump and components into self-contained miniaturized devices may provide significant improvements in DNA analysis speed, portability, and cost. The potential of microfabricated systems lies in the low unit cost of silicon-based construction and in the efficient sample handling afforded by component integration. Images Fig. 1 Fig. 2 Fig. 3 Fig. 4 Fig. 5 PMID:8643614

  5. Microfabrication and Nanotechnology in Stent Design

    PubMed Central

    Martinez, Adam W.; Chaikof, Elliot L.

    2012-01-01

    Intravascular stents were first introduced in the 1980s as an adjunct to primary angioplasty for management of early complications, including arterial dissection, or treatment of an inadequate technical outcome due to early elastic recoil of the atherosclerotic lesion. Despite the beneficial effects of stenting, persistent high rates of restenosis motivated the design of drug eluting stents for delivery of agents to limit the proliferative and other inflammatory responses within the vascular wall that contribute to the development of a restenotic lesion. These strategies have yielded a significant reduction in the incidence of restenosis, but challenges remain, including incomplete repair of the endothelium at the site of vascular wall injury that may be associated with a late risk of thrombosis. A failure of vessel wall healing has been attributed to primarily to the use of polymeric stent coatings, but the effects of the eluted drug and other material properties or design features of the stent cannot be excluded. Improvements in stent microfabrication, as well as the introduction of alternative materials may help to address those limitations that inhibit stent performance. This review describes the application of novel microfabrication processes and the evolution of new nanotechnologies that hold significant promise in eliminating existing shortcomings of current stent platforms. PMID:21462356

  6. Microfabricated wire arrays for Z-pinch.

    SciTech Connect

    Spahn, Olga Blum; Rowen, Adam M.; Cich, Michael Joseph; Peake, Gregory Merwin; Arrington, Christian L.; Nash, Thomas J.; Klem, John Frederick; Romero, Dustin Heinz

    2008-10-01

    Microfabrication methods have been applied to the fabrication of wire arrays suitable for use in Z. Self-curling GaAs/AlGaAs supports were fabricated as an initial route to make small wire arrays (4mm diameter). A strain relief structure that could be integrated with the wire was designed to allow displacements of the anode/cathode connections in Z. Electroplated gold wire arrays with integrated anode/cathode bus connections were found to be sufficiently robust to allow direct handling. Platinum and copper plating processes were also investigated. A process to fabricate wire arrays on any substrate with wire thickness up to 35 microns was developed. Methods to handle and mount these arrays were developed. Fabrication of wire arrays of 20mm diameter was demonstrated, and the path to 40mm array fabrication is clear. With some final investment to show array mounting into Z hardware, the entire process to produce a microfabricated wire array will have been demonstrated.

  7. Integration of microfabricated low resistance and thousand-turn coils for vibration energy harvesting

    NASA Astrophysics Data System (ADS)

    Zhang, Qian; Wang, Yufeng; Zhao, Lurui; Sok Kim, Eun

    2016-02-01

    This paper presents two microfabrication approaches for multi-layer coils for vibration-energy harvesters. A magnet array is arranged with alternating north- and south-orientation to provide a rapidly changing magnetic field for high electromagnetic energy conversion. Multi-turn spiral coils on silicon wafer are aligned to the magnet array for maximum magnetic flux change. One type of coil is made out of 300 μm-thick copper that is electroplated with silicon mold, and the other is built on 25 μm-thick copper electroplated with photoresist mold. The low resistive coils fabricated by the first approach are integrated in a microfabricated energy harvester of 17  ×  7  ×  1.7 mm3 (=0.2 cm3) weighing 0.8 g, which generates 14.3 μW power output (into 0.7 Ω load) from vibration amplitude of 6 μm at 250 Hz. The latter approach is used to make a 1080-turn coil for a microfabricated electromagnetic energy harvester with magnet array and plastic spring. Though the size and weight of the harvester are only 44  ×  20  ×  6 mm3 (=5.3 cm3) and 12 g, respectively, it generates 1.04 mW power output (into 190 Ω load) when it is vibrated at 75 Hz with vibration amplitude of 220 μm.

  8. Overtaking method based on sand-sifter mechanism: Why do optimistic value functions find optimal solutions in multi-armed bandit problems?

    PubMed

    Ochi, Kento; Kamiura, Moto

    2015-09-01

    A multi-armed bandit problem is a search problem on which a learning agent must select the optimal arm among multiple slot machines generating random rewards. UCB algorithm is one of the most popular methods to solve multi-armed bandit problems. It achieves logarithmic regret performance by coordinating balance between exploration and exploitation. Since UCB algorithms, researchers have empirically known that optimistic value functions exhibit good performance in multi-armed bandit problems. The terms optimistic or optimism might suggest that the value function is sufficiently larger than the sample mean of rewards. The first definition of UCB algorithm is focused on the optimization of regret, and it is not directly based on the optimism of a value function. We need to think the reason why the optimism derives good performance in multi-armed bandit problems. In the present article, we propose a new method, which is called Overtaking method, to solve multi-armed bandit problems. The value function of the proposed method is defined as an upper bound of a confidence interval with respect to an estimator of expected value of reward: the value function asymptotically approaches to the expected value of reward from the upper bound. If the value function is larger than the expected value under the asymptote, then the learning agent is almost sure to be able to obtain the optimal arm. This structure is called sand-sifter mechanism, which has no regrowth of value function of suboptimal arms. It means that the learning agent can play only the current best arm in each time step. Consequently the proposed method achieves high accuracy rate and low regret and some value functions of it can outperform UCB algorithms. This study suggests the advantage of optimism of agents in uncertain environment by one of the simplest frameworks. PMID:26166266

  9. Microfabricated Inserts for Magic Angle Coil Spinning (MACS) Wireless NMR Spectroscopy

    PubMed Central

    Badilita, Vlad; Fassbender, Birgit; Kratt, Kai; Wong, Alan; Bonhomme, Christian; Sakellariou, Dimitris; Korvink, Jan G.; Wallrabe, Ulrike

    2012-01-01

    This article describes the development and testing of the first automatically microfabricated probes to be used in conjunction with the magic angle coil spinning (MACS) NMR technique. NMR spectroscopy is a versatile technique for a large range of applications, but its intrinsically low sensitivity poses significant difficulties in analyzing mass- and volume-limited samples. The combination of microfabrication technology and MACS addresses several well-known NMR issues in a concerted manner for the first time: (i) reproducible wafer-scale fabrication of the first-in-kind on-chip LC microresonator for inductive coupling of the NMR signal and reliable exploitation of MACS capabilities; (ii) improving the sensitivity and the spectral resolution by simultaneous spinning the detection microcoil together with the sample at the “magic angle” of 54.74° with respect to the direction of the magnetic field (magic angle spinning – MAS), accompanied by the wireless signal transmission between the microcoil and the primary circuit of the NMR spectrometer; (iii) given the high spinning rates (tens of kHz) involved in the MAS methodology, the microfabricated inserts exhibit a clear kinematic advantage over their previously demonstrated counterparts due to the inherent capability to produce small radius cylindrical geometries, thus tremendously reducing the mechanical stress and tearing forces on the sample. In order to demonstrate the versatility of the microfabrication technology, we have designed MACS probes for various Larmor frequencies (194, 500 and 700 MHz) testing several samples such as water, Drosophila pupae, adamantane solid and LiCl at different magic angle spinning speeds. PMID:22936994

  10. Microfabricated inserts for magic angle coil spinning (MACS) wireless NMR spectroscopy.

    PubMed

    Badilita, Vlad; Fassbender, Birgit; Kratt, Kai; Wong, Alan; Bonhomme, Christian; Sakellariou, Dimitris; Korvink, Jan G; Wallrabe, Ulrike

    2012-01-01

    This article describes the development and testing of the first automatically microfabricated probes to be used in conjunction with the magic angle coil spinning (MACS) NMR technique. NMR spectroscopy is a versatile technique for a large range of applications, but its intrinsically low sensitivity poses significant difficulties in analyzing mass- and volume-limited samples. The combination of microfabrication technology and MACS addresses several well-known NMR issues in a concerted manner for the first time: (i) reproducible wafer-scale fabrication of the first-in-kind on-chip LC microresonator for inductive coupling of the NMR signal and reliable exploitation of MACS capabilities; (ii) improving the sensitivity and the spectral resolution by simultaneous spinning the detection microcoil together with the sample at the "magic angle" of 54.74° with respect to the direction of the magnetic field (magic angle spinning - MAS), accompanied by the wireless signal transmission between the microcoil and the primary circuit of the NMR spectrometer; (iii) given the high spinning rates (tens of kHz) involved in the MAS methodology, the microfabricated inserts exhibit a clear kinematic advantage over their previously demonstrated counterparts due to the inherent capability to produce small radius cylindrical geometries, thus tremendously reducing the mechanical stress and tearing forces on the sample. In order to demonstrate the versatility of the microfabrication technology, we have designed MACS probes for various Larmor frequencies (194, 500 and 700 MHz) testing several samples such as water, Drosophila pupae, adamantane solid and LiCl at different magic angle spinning speeds. PMID:22936994

  11. Microfabricated devices in microbial bioenergy sciences.

    PubMed

    Han, Arum; Hou, Huijie; Li, Lei; Kim, Hyun Soo; de Figueiredo, Paul

    2013-04-01

    Microbes provide a platform for the synthesis of clean energy from renewable resources. Significant investments in discovering new microbial systems and capabilities, discerning the molecular mechanisms that mediate microbial bioenergy production, and optimizing existing microbial bioenergy systems have been made. However, further development is needed to achieve the economically feasible large-scale production of value-added energy products. Microfabricated lab-on-a-chip systems provide cost- and time-efficient opportunities for analyzing microbe-mediated bioenergy synthesis. Here, we review developments in the application of lab-on-a-chip systems to the bioenergy sciences. We focus on systems that support the analysis of microbial generation of bioelectricity, biogas, and liquid transportation fuels. We conclude by suggesting possible future directions. PMID:23453527

  12. Microfabricated Platforms for Mechanically Dynamic Cell Culture

    PubMed Central

    Moraes, Christopher; Sun, Yu; Simmons, Craig A.

    2010-01-01

    The ability to systematically probe in vitro cellular response to combinations of mechanobiological stimuli for tissue engineering, drug discovery or fundamental cell biology studies is limited by current bioreactor technologies, which cannot simultaneously apply a variety of mechanical stimuli to cultured cells. In order to address this issue, we have developed a series of microfabricated platforms designed to screen for the effects of mechanical stimuli in a high-throughput format. In this protocol, we demonstrate the fabrication of a microactuator array of vertically displaced posts on which the technology is based, and further demonstrate how this base technology can be modified to conduct high-throughput mechanically dynamic cell culture in both two-dimensional and three-dimensional culture paradigms. PMID:21206477

  13. A microfabricated sensor for thin dielectric layers.

    PubMed

    Fierlinger, P; DeVoe, R; Flatt, B; Gratta, G; Green, M; Kolkowitz, S; Leport, F; Montero Diez, M; Neilson, R; O'Sullivan, K; Pocar, A; Wodin, J

    2008-04-01

    We describe a sensor for the measurement of thin dielectric layers capable of operation in a variety of environments. The sensor is obtained by microfabricating a capacitor with interleaved aluminum fingers, exposed to the dielectric to be measured. In particular, the device can measure thin layers of solid frozen from a liquid or gaseous medium. Sensitivity to single atomic layers is achievable in many configurations and, by utilizing fast, high sensitivity capacitance readout in a feedback system onto environmental parameters; coatings of few layers can be dynamically maintained. We discuss the design, readout, and calibration of several versions of the device optimized in different ways. We specifically dwell on the case in which atomically thin solid xenon layers are grown and stabilized, in cryogenic conditions, from a liquid xenon bath. PMID:18447546

  14. Micro-fabricated stylus ion trap.

    PubMed

    Arrington, Christian L; McKay, Kyle S; Baca, Ehren D; Coleman, Jonathan J; Colombe, Yves; Finnegan, Patrick; Hite, Dustin A; Hollowell, Andrew E; Jördens, Robert; Jost, John D; Leibfried, Dietrich; Rowen, Adam M; Warring, Ulrich; Weides, Martin; Wilson, Andrew C; Wineland, David J; Pappas, David P

    2013-08-01

    An electroformed, three-dimensional stylus Paul trap was designed to confine a single atomic ion for use as a sensor to probe the electric-field noise of proximate surfaces. The trap was microfabricated with the UV-LIGA technique to reduce the distance of the ion from the surface of interest. We detail the fabrication process used to produce a 150 μm tall stylus trap with feature sizes of 40 μm. We confined single, laser-cooled, (25)Mg(+) ions with lifetimes greater than 2 h above the stylus trap in an ultra-high-vacuum environment. After cooling a motional mode of the ion at 4 MHz close to its ground state ( = 0.34 ± 0.07), the heating rate of the trap was measured with Raman sideband spectroscopy to be 387 ± 15 quanta/s at an ion height of 62 μm above the stylus electrodes. PMID:24007096

  15. Non-planar microfabricated gas chromatography column

    DOEpatents

    Lewis, Patrick R.; Wheeler, David R.

    2007-09-25

    A non-planar microfabricated gas chromatography column comprises a planar substrate having a plurality of through holes, a top lid and a bottom lid bonded to opposite surfaces of the planar substrate, and inlet and outlet ports for injection of a sample gas and elution of separated analytes. A plurality of such planar substrates can be aligned and stacked to provide a longer column length having a small footprint. Furthermore, two or more separate channels can enable multi-channel or multi-dimensional gas chromatography. The through holes preferably have a circular cross section and can be coated with a stationary phase material or packed with a porous packing material. Importantly, uniform stationary phase coatings can be obtained and band broadening can be minimized with the circular channels. A heating or cooling element can be disposed on at least one of the lids to enable temperature programming of the column.

  16. Microfabricated structures with electrical isolation and interconnections

    NASA Technical Reports Server (NTRS)

    Clark, William A. (Inventor); Juneau, Thor N. (Inventor); Roessig, Allen W. (Inventor); Lemkin, Mark A. (Inventor)

    2001-01-01

    The invention is directed to a microfabricated device. The device includes a substrate that is etched to define mechanical structures at least some of which are anchored laterally to the remainder of the substrate. Electrical isolation at points where mechanical structures are attached to the substrate is provided by filled isolation trenches. Filled trenches may also be used to electrically isolate structure elements from each other at points where mechanical attachment of structure elements is desired. The performance of microelectromechanical devices is improved by 1) having a high-aspect-ratio between vertical and lateral dimensions of the mechanical elements, 2) integrating electronics on the same substrate as the mechanical elements, 3) good electrical isolation among mechanical elements and circuits except where electrical interconnection is desired.

  17. Guiding neuronal development with in situ microfabrication

    NASA Astrophysics Data System (ADS)

    Kaehr, Bryan; Allen, Richard; Javier, David J.; Currie, John; Shear, Jason B.

    2004-11-01

    We report the ability to modify microscopic 3D topographies within dissociated cultures, providing a means to alter the development of neurons as they extend neurites and establish interconnections. In this approach, multiphoton excitation is used to focally excite noncytotoxic photosensitizers that promote protein crosslinking, such as BSA, into matrices having feature sizes 250 nm. Barriers, growth lanes, and pinning structures comprised of crosslinked proteins are fabricated under conditions that do not compromise the viability of neurons both on short time scales and over periods of days. In addition, the ability to fabricate functional microstructures from crosslinked avidin enables submicrometer localization of controllable quantities of biotinylated ligands, such as indicators and biological effectors. Feasibility is demonstrated for using in situ microfabrication to guide the contact position of cortical neurons with micrometer accuracy, opening the possibility for engineering well defined sets of synaptic interactions. biofabrication | multiphoton cell patterning | growth cone

  18. Microfabricated instrument for tissue biopsy and analysis

    DOEpatents

    Krulevitch, Peter A.; Lee, Abraham P.; Northrup, M. Allen; Benett, William J.

    2001-01-01

    A microfabricated biopsy/histology instrument which has several advantages over the conventional procedures, including minimal specimen handling, smooth cutting edges with atomic sharpness capable of slicing very thin specimens (approximately 2 .mu.m or greater), micro-liter volumes of chemicals for treating the specimens, low cost, disposable, fabrication process which renders sterile parts, and ease of use. The cutter is a "cheese-grater" style design comprising a block or substrate of silicon and which uses anisotropic etching of the silicon to form extremely sharp and precise cutting edges. As a specimen is cut, it passes through the silicon cutter and lies flat on a piece of glass which is bonded to the cutter. Microchannels are etched into the glass or silicon substrates for delivering small volumes of chemicals for treating the specimen. After treatment, the specimens can be examined through the glass substrate.

  19. Level set method for microfabrication simulations

    NASA Astrophysics Data System (ADS)

    Baranski, Maciej; Kasztelanic, Rafal; Albero, Jorge; Nieradko, Lukasz; Gorecki, Christophe

    2010-05-01

    The article describes application of Level Set method for two different microfabrication processes. First is shape evolution of during reflow of the glass structure. Investigated problem were approximated by viscous flow of material thus kinetics of the process were known from physical model. Second problem is isotropic wet etching of silicon. Which is much more complicated because dynamics of the shape evolution is strongly coupled with time and geometry shapes history. In etching simulations Level Set method is coupled with Finite Element Method (FEM) that is used for calculation of etching acid concentration that determine geometry evolution of the structure. The problem arising from working with FEM with time varying boundaries was solved with the use of the dynamic mesh technique employing the Level Set formalism of higher dimensional function for geometry description. Isotropic etching was investigated in context of mico-lenses fabrication. Model was compared with experimental data obtained in etching of the silicon moulds used for micro-lenses fabrication.

  20. Magnetoencephalography of epilepsy with a microfabricated atomic magnetrode.

    PubMed

    Alem, Orang; Benison, Alex M; Barth, Daniel S; Kitching, John; Knappe, Svenja

    2014-10-22

    Magnetoencephalography has long held the promise of providing a noninvasive tool for localizing epileptic seizures in humans because of its high spatial resolution compared with the scalp EEG. Yet, this promise has been elusive, not because of a lack of sensitivity or spatial resolution but because the large size and immobility of present cryogenic (superconducting) technology prevent long-term telemetry required to capture these very infrequent epileptiform events. To circumvent this limitation, we used Micro-Electro-Mechanical Systems technology to construct a noncryogenic (room temperature) microfabricated atomic magnetometer ("magnetrode") based on laser spectroscopy of rubidium vapor and similar in size and flexibility to scalp EEG electrodes. We tested the magnetrode by measuring the magnetic signature of epileptiform discharges in a rat model of epilepsy. We were able to measure neuronal currents of single epileptic discharges and more subtle spontaneous brain activity with a high signal-to-noise ratio approaching that of present superconducting sensors. These measurements are a promising step toward the goal of high-resolution noninvasive telemetry of epileptic events in humans with seizure disorders. PMID:25339745

  1. Microfabrics in Siliceous Hotsprings: Yellowstone National Park, Wyoming

    NASA Technical Reports Server (NTRS)

    Guidry, S. A.; Chafetz, H. S.; Westall, F.

    2001-01-01

    Microfabrics shed light on the mechanisms governing siliceous sinter precipitation, the profound effects of microorganisms, as well as a conventional facies model for siliceous hotsprings. Additional information is contained in the original extended abstract.

  2. Microfabricated therapeutic actuators and release mechanisms therefor

    DOEpatents

    Lee, Abraham P.; Fitch, Joseph P.; Schumann, Daniel L.; Da Silva, Luiz; Benett, William J.; Krulevitch, Peter A.

    2000-01-01

    Microfabricated therapeutic actuators are fabricated using a shape memory polymer (SMP), a polyurethane-based material that undergoes a phase transformation at a specified temperature (Tg). At a temperature above temperature Tg material is soft and can be easily reshaped into another configuration. As the temperature is lowered below temperature Tg the new shape is fixed and locked in as long as the material stays below temperature Tg. Upon reheating the material to a temperature above Tg, the material will return to its original shape. By the use of such SMP material, SMP microtubing can be used as a retaining/release actuator for the delivery of material, such as embolic coils, for example, through catheters into aneurysms, for example. The microtubing can be manufactured in various sizes and the phase change temperature Tg is determinate for an intended temperature target and intended use. The SMP microtubing can be positioned around or within an end of a deposit material. Various heating arrangements can be utilized with the SMP release mechanism, and the SMP microtubing can include a metallic coating for enhanced light absorption.

  3. Microfabricated electrochemical sensors for combustion applications

    NASA Astrophysics Data System (ADS)

    Vulcano Rossi, Vitor A.; Mullen, Max R.; Karker, Nicholas A.; Zhao, Zhouying; Kowarz, Marek W.; Dutta, Prabir K.; Carpenter, Michael A.

    2015-05-01

    A new design for the miniaturization of an existing oxygen sensor is proposed based on the application of silicon microfabrication technologies to a cm sized O2 sensor demonstrated by Argonne National Laboratory and The Ohio State University which seals a metal/metal oxide within the structure to provide an integrated oxygen reference. The structural and processing changes suggested will result in a novel MEMS-based device meeting the semiconductor industry standards for cost efficiency and mass production. The MEMS design requires thin film depositions to create a YSZ membrane, palladium oxide reference and platinum electrodes. Pt electrodes are studied under operational conditions ensuring film conductivity over prolonged usage. SEM imaging confirms void formation after extended tests, consistent with the literature. Furthermore, hydrophilic bonding of pairs of silicon die samples containing the YSZ membrane and palladium oxide is discussed in order to create hermetic sealed cavities for oxygen reference. The introduction of tensile Si3N4 films to the backside of the silicon die generates bowing of the chips, compromising bond quality. This effect is controlled through the application of pressure during the initial bonding stages. In addition, KOH etching of the bonded die samples is discussed, and a YSZ membrane that survives the etching step is characterized by Raman spectroscopy.

  4. Characterization of implantable microfabricated fluid delivery devices.

    PubMed

    Rathnasingham, Ruben; Kipke, Daryl R; Bledsoe, Sanford C; McLaren, John D

    2004-01-01

    The formal characterization of the performance of microfluidic delivery devices is crucial for reliable in vivo application. A comprehensive laboratory technique was developed and used to optimize, calibrate and validate microfabricated fluid delivery devices. In vivo experiments were carried out to verify the accuracy and reliability of the pressure driven devices. Acute guinea pig experiments were conducted to measure the response to alpha-amino-3-hydroxy-5-methyl-4-isoxalone propionic acid, an excitatory neurotransmitter, at multiple locations in the inferior colliculus. A nondimensional parameter, Q, was successfully used to classify devices in terms of geometry alone (i.e., independent of fluid properties). Functional devices exhibited long-term linearity and reliability in delivering single phase, Newtonian fluids, in discrete volumes with a resolution of 500 picoliters at less than 0.45 lbf/in2 (30 mbar) pressure drop. Results for non-Newtonian fluids are not presented here. The acute results showed a proportional increase in the firing rate for delivered volumes of 2 nL up to 10 nL (at rates of between 0.1 and 1 nL/s). Flow characteristics are maintained during acute experiments and post-implant. A control experiment conducted with Ringer solution produced negligible effects, suggesting the results to be truly pharmacological. The experimental techniques employed have proven to be reliable and will be used for future calibration and testing of next generation chronic microfluidic delivery devices. PMID:14723503

  5. Microfabricated instrument for tissue biopsy and analysis

    SciTech Connect

    Krulevitch, P.A.; Lee, A.P.; Northrup, M.A.; Benett, W.J.

    1999-11-16

    This invention relates to a microfabricated biopsy/histology instrument which has several advantages over the conventional procedures. The advantages include: minimal specimen handling; smooth cutting edges with atomic sharpness capable of slicing very thin specimens (approximately 2 {mu}m or greater); micro-liter volumes of chemicals for treating the specimens; low cost; disposable; fabrication process which renders sterile parts; and ease of use. The cutter is a cheese-grater style design comprising a block or substrate of silicon and which uses anisotropic etching of the silicon to form extremely sharp and precise cutting edges. As a specimen is cut, it passes through the silicon cutter and lies flat on a piece of glass which is bonded to the cutter. Microchannels are etched into the glass or silicon substrates for delivering small volumes of chemicals for treating the specimen. After treatment, the specimens can be examined through the glass substrate. For automation purposes, microvalves and micropumps may be incorporated. Also, specimens in parallel may be cut and treated with identical or varied chemicals. The instrument is disposable due to its low cost and thus could replace current expensive microtome and histology equipment.

  6. Microfabricated adhesive mimicking gecko foot-hair

    NASA Astrophysics Data System (ADS)

    Geim, A. K.; Dubonos, S. V.; Grigorieva, I. V.; Novoselov, K. S.; Zhukov, A. A.; Shapoval, S. Yu.

    2003-07-01

    The amazing climbing ability of geckos has attracted the interest of philosophers and scientists alike for centuries. However, only in the past few years has progress been made in understanding the mechanism behind this ability, which relies on submicrometre keratin hairs covering the soles of geckos. Each hair produces a miniscule force ~10-7 N (due to van der Waals and/or capillary interactions) but millions of hairs acting together create a formidable adhesion of ~10 N cm-2: sufficient to keep geckos firmly on their feet, even when upside down on a glass ceiling. It is very tempting to create a new type of adhesive by mimicking the gecko mechanism. Here we report on a prototype of such 'gecko tape' made by microfabrication of dense arrays of flexible plastic pillars, the geometry of which is optimized to ensure their collective adhesion. Our approach shows a way to manufacture self-cleaning, re-attachable dry adhesives, although problems related to their durability and mass production are yet to be resolved.

  7. Microfabricated instrument for tissue biopsy and analysis

    DOEpatents

    Krulevitch, Peter A.; Lee, Abraham P.; Northrup, M. Allen; Benett, William J.

    1999-01-01

    A microfabricated biopsy/histology instrument which has several advantages over the conventional procedures, including minimal specimen handling, smooth cutting edges with atomic sharpness capable of slicing very thin specimens (approximately 2 .mu.m or greater), micro-liter volumes of chemicals for treating the specimens, low cost, disposable, fabrication process which renders sterile parts, and ease of use. The cutter is a "cheese-grater" style design comprising a block or substrate of silicon and which uses anisotropic etching of the silicon to form extremely sharp and precise cutting edges. As a specimen is cut, it passes through the silicon cutter and lies flat on a piece of glass which is bonded to the cutter. Microchannels are etched into the glass or silicon substrates for delivering small volumes of chemicals for treating the specimen. After treatment, the specimens can be examined through the glass substrate. For automation purposes, microvalves and micropumps may be incorporated. Also, specimens in parallel may be cut and treated with identical or varied chemicals. The instrument is disposable due to its low cost and thus could replace current expensive microtome and histology equipment.

  8. Fetal magnetocardiography measurements with an array of microfabricated optically pumped magnetometers

    NASA Astrophysics Data System (ADS)

    Alem, Orang; Sander, Tilmann H.; Mhaskar, Rahul; LeBlanc, John; Eswaran, Hari; Steinhoff, Uwe; Okada, Yoshio; Kitching, John; Trahms, Lutz; Knappe, Svenja

    2015-06-01

    Following the rapid progress in the development of optically pumped magnetometer (OPM) technology for the measurement of magnetic fields in the femtotesla range, a successful assembly of individual sensors into an array of nearly identical sensors is within reach. Here, 25 microfabricated OPMs with footprints of 1 cm3 were assembled into a conformal array. The individual sensors were inserted into three flexible belt-shaped holders and connected to their respective light sources and electronics, which reside outside a magnetically shielded room, through long optical and electrical cables. With this setup the fetal magnetocardiogram of a pregnant woman was measured by placing two sensor belts over her abdomen and one belt over her chest. The fetal magnetocardiogram recorded over the abdomen is usually dominated by contributions from the maternal magnetocardiogram, since the maternal heart generates a much stronger signal than the fetal heart. Therefore, signal processing methods have to be applied to obtain the pure fetal magnetocardiogram: orthogonal projection and independent component analysis. The resulting spatial distributions of fetal cardiac activity are in good agreement with each other. In a further exemplary step, the fetal heart rate was extracted from the fetal magnetocardiogram. Its variability suggests fetal activity. We conclude that microfabricated optically pumped magnetometers operating at room temperature are capable of complementing or in the future even replacing superconducting sensors for fetal magnetocardiography measurements.

  9. Fetal magnetocardiography measurements with an array of microfabricated optically pumped magnetometers.

    PubMed

    Alem, Orang; Sander, Tilmann H; Mhaskar, Rahul; LeBlanc, John; Eswaran, Hari; Steinhoff, Uwe; Okada, Yoshio; Kitching, John; Trahms, Lutz; Knappe, Svenja

    2015-06-21

    Following the rapid progress in the development of optically pumped magnetometer (OPM) technology for the measurement of magnetic fields in the femtotesla range, a successful assembly of individual sensors into an array of nearly identical sensors is within reach. Here, 25 microfabricated OPMs with footprints of 1 cm(3) were assembled into a conformal array. The individual sensors were inserted into three flexible belt-shaped holders and connected to their respective light sources and electronics, which reside outside a magnetically shielded room, through long optical and electrical cables. With this setup the fetal magnetocardiogram of a pregnant woman was measured by placing two sensor belts over her abdomen and one belt over her chest. The fetal magnetocardiogram recorded over the abdomen is usually dominated by contributions from the maternal magnetocardiogram, since the maternal heart generates a much stronger signal than the fetal heart. Therefore, signal processing methods have to be applied to obtain the pure fetal magnetocardiogram: orthogonal projection and independent component analysis. The resulting spatial distributions of fetal cardiac activity are in good agreement with each other. In a further exemplary step, the fetal heart rate was extracted from the fetal magnetocardiogram. Its variability suggests fetal activity. We conclude that microfabricated optically pumped magnetometers operating at room temperature are capable of complementing or in the future even replacing superconducting sensors for fetal magnetocardiography measurements. PMID:26041047

  10. Microfabricated glucose biosensor for culture well operation.

    PubMed

    Pemberton, R M; Cox, T; Tuffin, R; Sage, I; Drago, G A; Biddle, N; Griffiths, J; Pittson, R; Johnson, G; Xu, J; Jackson, S K; Kenna, G; Luxton, R; Hart, J P

    2013-04-15

    A water-based carbon screen-printing ink formulation, containing the redox mediator cobalt phthalocyanine (CoPC) and the enzyme glucose oxidase (GOx), was investigated for its suitability to fabricate glucose microbiosensors in a 96-well microplate format: (1) the biosensor ink was dip-coated onto a platinum (Pt) wire electrode, leading to satisfactory amperometric performance; (2) the ink was deposited onto the surface of a series of Pt microelectrodes (10-500 μm diameter) fabricated on a silicon substrate using MEMS (microelectromechanical systems) microfabrication techniques: capillary deposition proved to be successful; a Pt microdisc electrode of ≥100 μm was required for optimum biosensor performance; (3) MEMS processing was used to fabricate suitably sized metal (Pt) tracks and pads onto a silicon 96 well format base chip, and the glucose biosensor ink was screen-printed onto these pads to create glucose microbiosensors. When formed into microwells, using a 340 μl volume of buffer, the microbiosensors produced steady-state amperometric responses which showed linearity up to 5 mM glucose (CV=6% for n=5 biosensors). When coated, using an optimised protocol, with collagen in order to aid cell adhesion, the biosensors continued to show satisfactory performance in culture medium (linear range to 2 mM, dynamic range to 7 mM, CV=5.7% for n=4 biosensors). Finally, the operation of these collagen-coated microbiosensors, in 5-well 96-well format microwells, was tested using a 5-channel multipotentiostat. A relationship between amperometric response due to glucose, and cell number in the microwells, was observed. These results indicate that microphotolithography and screen-printing techniques can be combined successfully to produce microbiosensors capable of monitoring glucose metabolism in 96 well format cell cultures. The potential application areas for these microbiosensors are discussed. PMID:23265827

  11. Microfabricated Segmented-Involute-Foil Regenerator for Stirling Engines

    NASA Technical Reports Server (NTRS)

    Ibrahim, Mounir; Danila, Daniel; Simon, Terrence; Mantell, Susan; Sun, Liyong; Gedeon, David; Qiu, Songgang; Wood, Gary; Kelly, Kevin; McLean, Jeffrey

    2010-01-01

    An involute-foil regenerator was designed, microfabricated, and tested in an oscillating-flow test rig. The concept consists of stacked involute-foil nickel disks (see figure) microfabricated via a lithographic process. Test results yielded a performance of about twice that of the 90-percent random-fiber currently used in small Stirling converters. The segmented nature of the involute- foil in both the axial and radial directions increases the strength of the structure relative to wrapped foils. In addition, relative to random-fiber regenerators, the involute-foil has a reduced pressure drop, and is expected to be less susceptible to the release of metal fragments into the working space, thus increasing reliability. The prototype nickel involute-foil regenerator was adequate for testing in an engine with a 650 C hot-end temperature. This is lower than that required by larger engines, and high-temperature alloys are not suited for the lithographic microfabrication approach.

  12. Parylene C as a Sacrificial Material for Microfabrication

    NASA Technical Reports Server (NTRS)

    Beamesderfer, Michael

    2005-01-01

    Parylene C has been investigated for use as a sacrificial material in microfabrication. Although Parylene C cannot be patterned lithographically like photoresists, it nevertheless extends the range of processing options by offering a set of properties that are suitable for microfabrication and are complementary to those of photoresists. The compatibility of Parylene C with several microfabrication processes was demonstrated in experiments in which a thin film of Parylene C was deposited on a silicon wafer, then several thin metal films were deposited and successfully patterned, utilizing the Parylene C pads as a sacrificial layer. The term "parylene" -- a contraction of "poly(para-xylene)" -- denotes a family of vapor-deposited polymers. In Parylene C (the most common form of parylene), a chlorine atom is substituted for one of the hydrogen atoms on the benzene ring of each para-xylene moiety. Heretofore, parylenes have been used as conformal coating materials in diverse applications.

  13. Development of neutral atom traps based on a microfabricated waveguide

    NASA Astrophysics Data System (ADS)

    Jau, Yuan-Yu; Lee, Jongmin; Biedermann, Grant; Siddiqui, Aleem; Eichenfield, Matt; Dougla, Erica

    2016-05-01

    Implementation of trapping neutral atoms in the evanescent fields generated by a nano-structure, such as a nanofiber or a microfabricated nano-waveguide, will naturally enable strong atom-photon interactions, which serve the key mechanisms for different type of quantum controls. At Sandia National Labs, we are aiming to develop a platform based on this concept to eventually trap cesium atoms with a microfabricated waveguide. Although, neutral atom traps using optical nanofiber has been demonstrated, there are several key issues that need to be resolved to realize trapping atoms with microfabricated structure. The subjects include the material for making the waveguide, optical power handling capability, surface adsorption of alkali-metal atoms, surface roughness of the nano-structure, cold-atom source for loading the atoms into the evanescent-field traps, etc. We will discuss our studies on these related subjects and report our latest progress.

  14. Microfabrication of IPMC cilia for bio-inspired flow sensing

    NASA Astrophysics Data System (ADS)

    Lei, Hong; Li, Wen; Tan, Xiaobo

    2012-04-01

    As the primary flow sensing organ for fishes, the lateral line system plays a critical role in fish behavior. Analogous to its biological counterpart, an artificial lateral line system, consisting of arrays of micro flow sensors, is expected to be instrumental in the navigation and control of underwater robots. In this paper we investigate the microfabrication of ionic polymer-metal composite (IPMC) cilia for the purpose of flow sensing. While existing macro- and microfabrication methods for IPMCs have predominantly focused on planar structures, we propose a device where micro IPMC beams stand upright on a substrate to effectively interact with the flow. Challenges in the casting of 3D Nafion structure and selective formation of electrodes are discussed, and potential solutions for addressing these challenges are presented together with preliminary microfabrication results.

  15. Microfabricated biocapsules for the immunoisolation of pancreatic islets of Langerhans

    NASA Astrophysics Data System (ADS)

    Desai, Tejal Ashwin

    1998-08-01

    A silicon-based microfabricated biocapsule was developed and evaluated for use in the immunoisolation of transplanted cells, specifically pancreatic islets of Langerhans for the treatment of Type I diabetes. The transplantation of cells with specific functions is a promising therapy for a wide variety of pathologies including diabetes, Parkinson's, and hemophilia. Such transplanted cells, however, are sensitive to both cellular and humoral immune rejection as well as damage by autoimmune activity, without chronic immunosuppression. The research presented in this dissertation investigated whether microfabricated silicon-based biocapsules, with uniform membrane pore sizes in the tens of nanometer range, could provide an immunoprotective environment for pancreatic islets and other insulin-secreting cell lines, while maintaining cell viability and functionality. By utilizing fabrication techniques commonly employed in the microelectronics industry (MEMS), membranes were fabricated with precisely controlled and uniform pore sizes, allowing the optimization of biocapsule membrane parameters for the encapsulation of specific hormone-secreting cell types. The biocapsule-forming process employed bulk micromachining to define cell-containing chambers within single crystalline silicon wafers. These chambers interface with the surrounding biological environment through polycrystalline silicon filter membranes, which were surface micromachined to present a high density of uniform pores to allow sufficient permeability to oxygen, glucose, and insulin. Both in vitro and in vivo experiments established the biocompatibility of the microfabricated biocapsule, and demonstrated that encapsulated cells could live and function normally in terms of insulin-secretion within microfabricated environments for extended periods of time. This novel research shows the potential of using microfabricated biocapsules for the encapsulation of several different cell xenografts. The semipermeability

  16. Microfabricated Chemical Sensors for Safety and Emission Control Applications

    NASA Technical Reports Server (NTRS)

    Hunter, G. W.; Neudeck, P. G.; Chen, L.-Y.; Knight, D.; Liu, C. C.; Wu, Q. H.

    1998-01-01

    Chemical sensor technology is being developed for leak detection, emission monitoring, and fire safety applications. The development of these sensors is based on progress in two types of technology: 1) Micromachining and microfabrication (MicroElectroMechanical Systems (MEMS)-based) technology to fabricate miniaturized sensors. 2) The development of high temperature semiconductors, especially silicon carbide. Using these technologies, sensors to measure hydrogen, hydrocarbons, nitrogen oxides, carbon monoxide, oxygen, and carbon dioxide are being developed. A description is given of each sensor type and its present stage of development. It is concluded that microfabricated sensor technology has significant potential for use in a range of aerospace applications.

  17. Microfabricated suspensions for electrical connections on the tunable elastomer membrane

    NASA Astrophysics Data System (ADS)

    Hung, Paul J.; Jeong, Kihun; Liu, Gang L.; Lee, Luke P.

    2004-12-01

    Electrical connections through microfabricated suspensions on a pneumatically pumped elastomer membrane were demonstrated. A method to fabricate the suspensions on the elastomer membrane was developed. The elastomer membrane was 1 mm in diameter and 120 μm in thickness. Resistances of the microfabricated suspensions measured across the elastomer membrane were within 1% difference when the membrane's center deflection ranged from 0 to 100 μm, which corresponded to a numerical aperture change from 0 to 0.2 as well as a 2.6% elongation of the elastomer.

  18. Microfabrics in depleted mantle plaeotransform (New Caledonia)

    NASA Astrophysics Data System (ADS)

    Teyssier, Christian; Chatzaras, Vasileios; Von Der Handt, Anette

    2016-04-01

    The New Caledonia ophiolite contains several wrench zones that have been interpreted as paleotransforms. These transform-ridge systems developed at the transition between ridge development and intra-oceanic subduction that resulted in depleted mantle (about 18 % melt according to olivine Mg# - spinel Cr#). The most prominent is the Bogota Peninsula paleotransform, a 10 km wide shear zone in which strain localizes in the 2 km wide Ouassé mylonite zone. This strain gradient is associated with microstructure and microfabric evolution that informs the relationship between hydration and strain in mantle mylonite. Olivine recrystallized grain size varies from about 1 mm to about 0.2 mm toward the mylonite zone. The strain gradient is also demonstrated by increasing deformation of orthopyroxene (opx) grains that become elongate porphyroclasts in the mylonite zone. Orthopyroxene geothermometry reveals T ~ 1050-1000 C (Ca-opx) and 950-850 C (Cr-Al-opx) in the least deformed rocks. In the mylonite zone a wider range of T is recorded, with minima reaching 850 C (Ca-opx) and 750 C (Cr-Al-opx). Electron microprobe analysis also detects the presence of 20-200 micron interstitial, high-temperature amphibole (pargasite), with modal abundance increasing in the mylonite zone; this suggests that high-temperature pervasive fluid flow may have played a role in strain localization and mylonitization. Olivine crystallographic fabrics include A-type and E-type, the latter possibly reflecting hydration of shear zone tectonites. E-type fabrics are present in both mylonite and less deformed rocks, and appear to be more common in rocks with olivine grain size < 400 microns. A correlation between E-type fabrics and amphibole mode is being investigated. The shear zone protolith was depleted mantle in which the ridge-transform system was permeated by fluids. These fluids initially originated at the subduction interface, but during the transform evolution, ocean water likely permeated the shear

  19. Experimental Characterization of Microfabricated VirtualImpactor Efficiency

    EPA Science Inventory

    The Air-Microfluidics Group is developing a microelectromechanical systems-based direct reading particulate matter (PM) mass sensor. The sensor consists of two main components: a microfabricated virtual impactor (VI) and a PM mass sensor. The VI leverages particle inertia to sepa...

  20. Microfabricated Tactile Sensors for Biomedical Applications: A Review

    PubMed Central

    Saccomandi, Paola; Schena, Emiliano; Oddo, Calogero Maria; Zollo, Loredana; Silvestri, Sergio; Guglielmelli, Eugenio

    2014-01-01

    During the last decades, tactile sensors based on different sensing principles have been developed due to the growing interest in robotics and, mainly, in medical applications. Several technological solutions have been employed to design tactile sensors; in particular, solutions based on microfabrication present several attractive features. Microfabrication technologies allow for developing miniaturized sensors with good performance in terms of metrological properties (e.g., accuracy, sensitivity, low power consumption, and frequency response). Small size and good metrological properties heighten the potential role of tactile sensors in medicine, making them especially attractive to be integrated in smart interfaces and microsurgical tools. This paper provides an overview of microfabricated tactile sensors, focusing on the mean principles of sensing, i.e., piezoresistive, piezoelectric and capacitive sensors. These sensors are employed for measuring contact properties, in particular force and pressure, in three main medical fields, i.e., prosthetics and artificial skin, minimal access surgery and smart interfaces for biomechanical analysis. The working principles and the metrological properties of the most promising tactile, microfabricated sensors are analyzed, together with their application in medicine. Finally, the new emerging technologies in these fields are briefly described. PMID:25587432

  1. Nano- and microfabrication for overcoming drug delivery challenges

    PubMed Central

    Kam, Kimberly R.

    2013-01-01

    This highlight article describes current nano- and microfabrication techniques for creating drug delivery devices. We first review the main physiological barriers to delivering therapeutic agents. Then, we describe how novel fabrication methods can be utilized to combine many features into a single physiologically relevant device to overcome drug delivery challenges. PMID:23730504

  2. Recent progress of laser precision microfabrication in China

    NASA Astrophysics Data System (ADS)

    Cheng, Zhaogu; Xu, Guoliang; Zhao, Quanzhong; Liu, Cuiqing

    2002-02-01

    Review on recent progress of laser precision microfabrication in China is given in this paper. The universal fields of the LPM mostly using short pulse and short wavelength lasers in China are as follows: new materials, advanced manufacturing technology, information technology, biological technology, medical treatment and so on, which are given priority to the development in high-tech fields in China.

  3. Sub-picotesla Scalar Atomic Magnetometer with a Microfabricated Vapor Cell

    NASA Astrophysics Data System (ADS)

    Zhang, Rui; Mhaskar, Rahul

    2016-05-01

    We explore the sensitivity limits of scalar atomic magnetometry with a micro-fabricated Cs vapor cell. The millimeter-scale cell is fabricated using silicon Micro-Electro-Mechanical Systems (MEMS) technology. The atomic spin procession is driven by an amplitude-modulated circularly polarized pump laser resonant with the D1 transition in Cs atoms. The precession is detected by an off-resonant linearly polarized probe laser using a balanced polarimeter setup. The probe light is spatially split into two beams to perform a gradiometer measurement. In a magnetic field of magnitude within the range of the earth magnetic field, we measure a sensitivity of less than 150 fT/ √Hz in the gradiometer mode, which shows that the magnetometer by itself can achieve sub-100 fT/ √Hz sensitivitiy. In addition to its high sensitivity, the magnetometer has a bandwidth of nearly 1 kHz due to the broad magnetic resonance inside the small cell. Our experiment suggests the feasibility of a portable, low-power and high-performance magnetometer, which can be operated in the earth's magnetic field. Such a device will greatly expand the range of applications for atomic magnetometers, such as the detection of nuclear magnetic resonance in an unshielded environment.

  4. Solid state synthesis of chitosan and its unsaturated derivatives for laser microfabrication of 3D scaffolds

    NASA Astrophysics Data System (ADS)

    Akopova, T. A.; Demina, T. S.; Bagratashvili, V. N.; Bardakova, K. N.; Novikov, M. M.; Selezneva, I. I.; Istomin, A. V.; Svidchenko, E. A.; Cherkaev, G. V.; Surin, N. M.; Timashev, P. S.

    2015-07-01

    Chitosans with various degrees of deacetylation and molecular weights and their allyl substituted derivatives were obtained through a solvent-free reaction under shear deformation in an extruder. Structure and physical-chemical analysis of the samples were carried out using nuclear magnetic resonance (NMR), ultraviolet (UV) and infrared radiation (IR) spectroscopy. Photosensitive materials based on the synthesized polymers were successfully used for microfabrication of 3D well-defined architectonic structures by laser stereolithography. Study on the metabolic activity of NCTC L929 cultured in the presence of the cured chitosan extracts indicates that the engineered biomaterials could support adhesion, spreading and growth of adherent-dependent cells, and thus could be considered as biocompatible scaffolds.

  5. Method For Chemical Sensing Using A Microfabricated Teeter-Totter Resonator

    DOEpatents

    Adkins, Douglas Ray; Heller, Edwin J.; Shul, Randy J.

    2004-11-30

    A method for sensing a chemical analyte in a fluid stream comprises providing a microfabricated teeter-totter resonator that relies upon a Lorentz force to cause oscillation in a paddle, applying a static magnetic field substantially aligned in-plane with the paddle, energizing a current conductor line on a surface of the paddle with an alternating electrical current to generate the Lorentz force, exposing the resonator to the analyte, and detecting the response of the oscillatory motion of the paddle to the chemical analyte. Preferably, a chemically sensitive coating is disposed on at least one surface of the paddle to enhance the sorption of the analyte by the paddle. The concentration of the analyte in a fluid stream can be determined by measuring the change in the resonant frequency or phase of the teeter-totter resonator as the chemical analyte is added to or removed from the paddle.

  6. ANKA, a customer-oriented synchrotron radiation facility for microfabrication and analytical services

    NASA Astrophysics Data System (ADS)

    Pea Anka Project Group; Buth, G.; Doyle, S.; Einfeld, D.; Hagelstein, M.; Hermle, S.; Huttel, E.; Krüssel, A.; Lange, M.; Mathis, Y.-L.; Mexner, W.; Moser, H. O.; Pellegrin, E.; Ristau, U.; Rossmanith, R.; Schaper, J.; Schieler, H.; Simon, R.; Steininger, R.; Voigt, S.; Walther, R.; Perez, F.; Pont, M.; Plesko, M.

    1998-03-01

    ANKA (Angströmquelle Karlsruhe) is a state-of-the-art synchrotron radiation facility under construction at the Forschungszentrum Karlsruhe. Based on a 2.5 GeV electron storage ring it will deliver photons predominantly in the hard X-ray range but it will also feature both XUV and infrared beamlines. In its first operational phase the radiation will be taken out of normal-conducting dipole bending magnets, while five free long straight sections are foreseen to accommodate insertion devices later on. ANKA has a novel mission, namely to provide synchrotron-radiation based services to industrial and other customers, in the fields of microfabrication and materials analysis. A limited liability company, ANKA GmbH, is being founded to operate the facility. Although commercial services to customers will represent more than half of the overall activity, these services will be complemented by providing beam time for research users.

  7. Microfabricated devices for performing chemical and biochemical analysis

    SciTech Connect

    Ramsey, J.M.; Jacobson, S.C.; Foote, R.S.

    1997-05-01

    There is growing interest in microfabricated devices that perform chemical and biochemical analysis. The general goal is to use microfabrication tools to construct miniature devices that can perform a complete analysis starting with an unprocessed sample. Such devices have been referred to as lab-on-a-chip devices. Initial efforts on microfluidic laboratory-on-a-chip devices focused on chemical separations. There are many potential applications of these fluidic microchip devices. Some applications such as chemical process control or environmental monitoring would require that a chip be used over an extended period of time or for many analyses. Other applications such as forensics, clinical diagnostics, and genetic diagnostics would employ the chip devices as single use disposable devices.

  8. Microfabricated cantilever-based detector for molecular beam experiments

    NASA Astrophysics Data System (ADS)

    Bachels, T.; Schäfer, R.

    1998-11-01

    A low cost detector for particles in molecular beam experiments is presented which can easily be mounted in a molecular beam apparatus. The detector is based on microfabricated cantilevers, which can be employed either as single sensors or as sensor arrays. The single cantilever technique has been used to measure the absolute number of atoms coming out of a pulsed laser vaporization cluster source. The particles are detected by the shift of the thermally excited resonance frequency of the cantilever due to the cluster deposition. We have determined with the single cantilever the ratio of neutral to ionized clusters and we have investigated the cluster generation at different source conditions. In addition to this, a microfabricated cantilever array has been used to measure molecular beam profiles, which opens new possibilities for molecular beam deflection experiments.

  9. Multilayered Ge/SiGe Material in Microfabricated Thermoelectric Modules

    NASA Astrophysics Data System (ADS)

    Samarelli, A.; Llin, L. Ferre; Cecchi, S.; Chrastina, D.; Isella, G.; Etzelstorfer, T.; Stangl, J.; Gubler, E. Muller; Weaver, J. M. R.; Dobson, P.; Paul, D. J.

    2014-10-01

    Results for low dimensional p-type Ge/SiGe superlattices with Ge quantum wells of 3.43 nm are presented. A range of microfabricated test structures have been developed to characterise the cross-plane electrical and thermal properties of the Ge/SiGe heterostructures. These superlattices were directly grown on 100-mm-diameter silicon wafers by a chemical vapour deposition growth system with rates up to 6 nm/s. Quantum well and quantum mechanical tunnel barriers with dimensions down to nm have been designed, grown and tested; they demonstrate a ZT of 0.08 ± 0.011 and power factor of 1.34 ± 0.15 m W m-1 K-2 at 300 K. A complete microfabricated module using indium bump-bonding is reported together with preliminary results on unoptimised material and leg dimensions. Routes to optimise the material and modules are discussed.

  10. Multilayer Interconnects for Microfabricated Surface Electrode Ion Traps

    NASA Astrophysics Data System (ADS)

    Amini, Jason; Seidelin, Signe; Wesenberg, Janus; Britton, Joe; Blakestad, Brad; Brown, Kenton; Epstein, Ryan; Home, Jonathan; Jost, John; Langer, Chris; Leibfried, Dietrich; Ozeri, Roee; Wineland, David

    2007-06-01

    Microfabricated surface electrode traps for ions are a promising technology for building scalable trapping geometries for quantum information processing. We have expanded upon our single layer gold-on-fused-silica surface electrode trap [1] to include a second patterned conducting layer under the trapping electrodes and have demonstrated the fabrication of this architecture using standard microfabrication techniques. The multilayer approach allows for a significant increase in multi-zone trapping complexity and permits improved trapping structures that are otherwise unattainable in single layer designs without vertical interconnects through the wafer. Using improved calculational methods [2], we are in the process of optimizing the planar designs to create modular elements that can be joined into larger multi-zone trapping structures. Work supported by DTO and NIST. 1. S. Seidelin et al., Phys. Rev. Lett. 96, 253003 (2006). Also, see the abstract by S. Seidelin. 2. See the abstract by J. H. Wesenberg.

  11. Guided Homing of Cells in Multi-Photon Microfabricated Bioscaffolds.

    PubMed

    Skylar-Scott, Mark A; Liu, Man-Chi; Wu, Yuelong; Dixit, Atray; Yanik, Mehmet Fatih

    2016-05-01

    Tissues contain exquisite vascular microstructures, and patterns of chemical cues for directing cell migration, homing, and differentiation for organ development and function. 3D microfabrication by multi-photon photolithography is a flexible, high-resolution tool for generating 3D bioscaffolds. However, the combined fabrication of scaffold microstructure simultaneously with patterning of cues to create both geometrically and chemically defined microenvironments remains to be demonstrated. This study presents a high-speed method for micron-resolution fabrication of scaffold microstructure and patterning of protein cues simultaneously using native scaffold materials. By the simultaneous microfabrication of arbitrary microvasculature geometries, and patterning selected regions of the microvasculature with the homing ligand P-selectin, this study demonstrates adhesion, rolling, and selective homing of cells in defined 3D regions. This novel ability to generate high-resolution geometries replete with patterned cues at high speed enables the construction of biomimetic microenvironments for complex 3D assays of cellular behavior. PMID:27059425

  12. SEM microfabric analysis of glacial varves, Geneseo, N. Y

    SciTech Connect

    Pietraszek, S.R. . Geology Dept.)

    1993-03-01

    A detailed study of the microfabric of Pleistocene varved silty-clay from Geneseo Valley (Geneseo, N.Y.) indicates rapid deposition of sediment in a flocculated state into a glacial lake. Ten varve couplets of a 10 cm thick sample were studied using the Scanning Electron Microscope to determine their microfabric. Each varve ranges from 0.5 cm to 2.0 cm and represents an annual ( ) deposit. Varves consists of a lower light colored, coarse zone of silt and clay, and an upper darker colored, organic fine clayey zone. Graded bedding is observed in each couplet, and random clay particle orientation is dominant throughout a varve, with the exception of the top 0.5 mm of the fine layer. The upper and lower contacts are sharp. Fabric features are instrumental in reconstructing a depositional environment. Microfabric results of the glacial unit indicate that an initial heavy concentration of clay and silt was introduced into the basin in a single pulse during spring runoff. The majority of silt settled together with clay in a flocculated or aggregated state, forming the lower coarse zone of random orientation. As the silt concentration diminished, the clay continued to flocculate and settled as a fine clay aggregate. It is proposed that the settling took place during the spring and summer months. Finally, during the winter months, the sediment surface of the varve was disturbed by nemotode burrows, which reoriented the clay flakes into a zone of preferred fabric. Microfabric analysis of these glacial varves, thus suggests that sediment was rapidly deposited in a flocculated state.

  13. Micro-Fabricated DC Comparison Calorimeter for RF Power Measurement

    PubMed Central

    Neji, Bilel; Xu, Jing; Titus, Albert H.; Meltzer, Joel

    2014-01-01

    Diode detection and bolometric detection have been widely used to measure radio frequency (RF) power. However, flow calorimeters, in particular micro-fabricated flow calorimeters, have been mostly unexplored as power meters. This paper presents the design, micro-fabrication and characterization of a flow calorimeter. This novel device is capable of measuring power from 100 μW to 200 mW. It has a 50-Ohm load that is heated by the RF source, and the heat is transferred to fluid in a microchannel. The temperature change in the fluid is measured by a thermistor that is connected in one leg of a Wheatstone bridge. The output voltage change of the bridge corresponds to the RF power applied to the load. The microfabricated device measures 25.4 mm × 50.8 mm, excluding the power supplies, microcontroller and fluid pump. Experiments demonstrate that the micro-fabricated sensor has a sensitivity up to 22 × 10−3 V/W. The typical resolution of this micro-calorimeter is on the order of 50 μW, and the best resolution is around 10 μW. The effective efficiency is 99.9% from 0–1 GHz and more than 97.5% at frequencies up to 4 GHz. The measured reflection coefficient of the 50-Ohm load and coplanar wave guide is less than −25 dB from 0–2 GHz and less than −16 dB at 2–4 GHz. PMID:25350509

  14. Impact of microfabrication technology on x-ray optics

    SciTech Connect

    Ceglio, N.M.

    1981-08-01

    X-ray optics stands on the threshold of realizing its early promise: precision analysis of microstructure on the scale of the x-ray wavelength. The achievement of this exciting goal will depend in large part on advances in microfabrication technology making possible the precision fabrication of periodic microstructures. A review of recent advances in, as well as future prospects for: x-ray microscopy, coded imaging, and space-time resolved spectroscopy, resulting from improved microstructure fabrication capabilities is presented.

  15. A microfabrication-based approach to quantitative isothermal titration calorimetry.

    PubMed

    Wang, Bin; Jia, Yuan; Lin, Qiao

    2016-04-15

    Isothermal titration calorimetry (ITC) directly measures heat evolved in a chemical reaction to determine equilibrium binding properties of biomolecular systems. Conventional ITC instruments are expensive, use complicated design and construction, and require long analysis times. Microfabricated calorimetric devices are promising, although they have yet to allow accurate, quantitative ITC measurements of biochemical reactions. This paper presents a microfabrication-based approach to integrated, quantitative ITC characterization of biomolecular interactions. The approach integrates microfabricated differential calorimetric sensors with microfluidic titration. Biomolecules and reagents are introduced at each of a series of molar ratios, mixed, and allowed to react. The reaction thermal power is differentially measured, and used to determine the thermodynamic profile of the biomolecular interactions. Implemented in a microdevice featuring thermally isolated, well-defined reaction volumes with minimized fluid evaporation as well as highly sensitive thermoelectric sensing, the approach enables accurate and quantitative ITC measurements of protein-ligand interactions under different isothermal conditions. Using the approach, we demonstrate ITC characterization of the binding of 18-Crown-6 with barium chloride, and the binding of ribonuclease A with cytidine 2'-monophosphate within reaction volumes of approximately 0.7 µL and at concentrations down to 2mM. For each binding system, the ITC measurements were completed with considerably reduced analysis times and material consumption, and yielded a complete thermodynamic profile of the molecular interaction in agreement with published data. This demonstrates the potential usefulness of our approach for biomolecular characterization in biomedical applications. PMID:26655185

  16. Microelectrode arrays fabricated using a novel hybrid microfabrication method.

    PubMed

    Merlo, Mark W; Snyder, Russell L; Middlebrooks, John C; Bachman, Mark

    2012-02-01

    We present novel hybrid microfabrication methods for microelectrode arrays that combine microwire assembly, microelectromechanical systems (MEMS) manufacturing techniques and precision tool-based micromachining. This combination enables hybrid microfabrication to produce complex geometries and structures, increase material selection, and improve integration. A 32-channel shank microelectrode array was fabricated to highlight the hybrid microfabrication techniques. The electrode shank was 130 μm at its narrowest, had a 127 μm thickness and had iridium oxide electrode sites that were 25 μm in diameter with 150 μm spacing. Techniques used to fabricate this electrode include microassembly of insulated gold wires into a micromold, micromolding the microelectrode shank, post molding machining, sacrificial release of the microelectrode and electrodeposition of iridium oxide onto the microelectrode sites. Electrode site position accuracy was shown to have a standard deviation of less than 4 μm. Acute in vivo recordings with the 32-channel shank microelectrode array demonstrated comparable performance to that obtained with commercial microelectrode arrays. This new approach to microelectrode array fabrication will enable new microelectrodes, such as multi-sided arrays, drug eluding electrodes and biodegradable shanks. PMID:21979567

  17. Microelectrode arrays fabricated using a novel hybrid microfabrication method

    PubMed Central

    Merlo, Mark W.; Snyder, Russell L.; Middlebrooks, John C.; Bachman, Mark

    2011-01-01

    We present novel hybrid microfabrication methods for microelectrode arrays that combine microwire assembly, microelectromechanical systems (MEMS) manufacturing techniques and precision tool-based micromachining. This combination enables hybrid microfabrication to produce complex geometries and structures, increase material selection, and improve integration. A 32-channel shank microelectrode array was fabricated to highlight the hybrid microfabrication techniques. The electrode shank was 130 μm at its narrowest, had a 127 μm thickness and had iridium oxide electrode sites that were 25 μm in diameter with 150 μm spacing. Techniques used to fabricate this electrode include microassembly of insulated gold wires into a micromold, micromolding the microelectrode shank, post molding machining, sacrificial release of the microelectrode and electrodeposition of iridium oxide onto the microelectrode sites. Electrode site position accuracy was shown to have a standard deviation of less than 4 μm. Acute in vivo recordings with the 32-channel shank microelectrode array demonstrated comparable performance to that obtained with commercial microelectrode arrays . This new approach to microelectrode array fabrication will enable new microelectrodes, such as multi-sided arrays, drug eluding electrodes and biodegradable shanks. PMID:21979567

  18. Applied Geophysics in the world of tomorrow - Microfabrication arrives

    NASA Astrophysics Data System (ADS)

    Johnson, R. M.

    2012-12-01

    Instrument manufacturers have a unique perspective on the design and use of geophysical equipment. The field instrument must provide reliable and repeatable performance in every climate condition and environmental extreme. The gear must be easy to use and more importantly easy to understand for non-native English speakers. I have traveled the world installing, repairing, commissioning and demonstrating geophysical survey systems. Everywhere I have traveled there is one unassailable fact - our geophysicist compatriots in developed and developing countries are hungry for information and hungry for technology. They want more and better systems to help improve their understanding of the subsurface. And they want to serve their countries by helping to exploit natural resources. I hold up for your review the first highly successful portable magnetometer, the G-856. Designed in 1981 with over 5000 sold, it is still produced in record numbers today for use all over the world. How could it be that a rather simple device could be so long lived, and make such an impact in exploration programs for 32 years? The answer is in producing reliable and easy to use equipment that is affordable. One might compare it to the iPad or Android device of today. The innovative and no-frills interface has attracted users from all markets including mining, oil/gas, archaeology, environmental, UXO/military and forensics. Powerful ancillary software to process the data has always been included at no charge, offering geoscientists a solution rather than a black box. Many of our technologies are poised for dramatic breakthroughs in miniaturization and interconnectivity. I point specifically to the micro-fabrication of the cesium vapor magnetometer. Initiated 5 years ago in conjunction with NIST, Geometrics has embarked on a high stakes game of minimizing size, weight, power consumption and price while eliminating dead zones and maintaining or increasing sensitivity and sample speed. These new

  19. Microfabricated sensors for the measurement of electromagnetic fields in biological tissues

    NASA Astrophysics Data System (ADS)

    Monberg, James; Henning, Albert K.

    1995-09-01

    Public awareness of the risks of exposure to electromagnetic radiation has grown over the past ten yeras. The effects of power lines on human and animal health have drawn particular attention. Some longitudinal studies of cancer rates near power lines show a significant correlation, while others show a null result. The studies have suffered from inadequate sensors for the measurement of electromagnetic radiation in vivo. In this work, we describe the design, construction, and testing of electrically passive, microfabricated single-pole antennas and coils. These sensors will be used in vivo to study the effects of electromagnetic radiation on animals. Our testing to date has been limited to in vitro studies of the magnetic field probes. Magnetic field pickup coils were fabricated with up to 100 turns, over a length of up to 1000 micrometers . Measurements were carried out with the sensors in air, and in water of various saline concentrations. Magnetic fields were applied using a Helmholtz coil. Both dc and ac fields were applied. The results indicate that small-area measurements of electromagnetic fields in vitro can be made successfully, provided adequate shielding and amplification are used.

  20. Enhanced adhesion for LIGA microfabrication by using a buffer layer

    DOEpatents

    Bajikar, Sateesh S.; De Carlo, Francesco; Song, Joshua J.

    2001-01-01

    The present invention is an improvement on the LIGA microfabrication process wherein a buffer layer is applied to the upper or working surface of a substrate prior to the placement of a resist onto the surface of the substrate. The buffer layer is made from an inert low-Z material (low atomic weight), a material that absorbs secondary X-rays emissions from the substrate that are generated from the substrate upon exposure to a primary X-rays source. Suitable materials for the buffer layer include polyamides and polyimide. The preferred polyimide is synthesized form pyromellitic anhydride and oxydianiline (PMDA-ODA).

  1. Enhanced adhesion for LIGA microfabrication by using a buffer layer

    SciTech Connect

    Bajikar, Sateesh S.; De Carlo, Francesco; Song, Joshua J.

    2004-01-27

    The present invention is an improvement on the LIGA microfabrication process wherein a buffer layer is applied to the upper or working surface of a substrate prior to the placement of a resist onto the surface of the substrate. The buffer layer is made from an inert low-Z material (low atomic weight), a material that absorbs secondary X-rays emissions from the substrate that are generated from the substrate upon exposure to a primary X-rays source. Suitable materials for the buffer layer include polyamides and polyimide. The preferred polyimide is synthesized form pyromellitic anhydride and oxydianiline (PMDA-ODA).

  2. Microfabricated, flowthrough porous apparatus for discrete detection of binding reactions

    DOEpatents

    Beattie, Kenneth L.

    1998-01-01

    An improved microfabricated apparatus for conducting a multiplicity of individual and simultaneous binding reactions is described. The apparatus comprises a substrate on which are located discrete and isolated sites for binding reactions. The apparatus is characterized by discrete and isolated regions that extend through said substrate and terminate on a second surface thereof such that when a test sample is allowed to the substrate, it is capable of penetrating through each such region during the course of said binding reaction. The apparatus is especially useful for sequencing by hybridization of DNA molecules.

  3. Cell lysis and DNA extraction in microfabricated devices

    NASA Astrophysics Data System (ADS)

    Prinz, Christelle; Tegenfeldt, Jonas; Austin, Robert

    2002-03-01

    We are developing a microfabricated device to lyse single cells and extract the DNA. The chip consists of two parts: a diffuse mixer combined with a dielectrophoretic trap. We are working with E. coli which have been made osmoticaly unstable before loading into the chip. The cells are lysed by osmotic shock in the mixer. The lysate is then passed to the dielectrophoretic trap. Attempts to separate the genomic DNA from the lysate fragments by selectively trapping the DNA using dielectrophoresis have been made. We have encountered cell sticking problems and are investingating surface modifications using Polyethylene glycol to solve this problem.

  4. Concentrating Genomic Length DNA in a Microfabricated Array

    NASA Astrophysics Data System (ADS)

    Chen, Yu; Abrams, Ezra S.; Boles, T. Christian; Pedersen, Jonas N.; Flyvbjerg, Henrik; Austin, Robert H.; Sturm, James C.

    2015-05-01

    We demonstrate that a microfabricated bump array can concentrate genomic-length DNA molecules efficiently at continuous, high flow velocities, up to 40 μ m /s , if the single-molecule DNA globule has a sufficiently large shear modulus. Increase in the shear modulus is accomplished by compacting the DNA molecules to minimal coil size using polyethylene glycol (PEG) derived depletion forces. We map out the sweet spot, where concentration occurs, as a function of PEG concentration and flow speed using a combination of theoretical analysis and experiment. Purification of DNA from enzymatic reactions for next-generation DNA-sequencing libraries will be an important application of this development.

  5. Near-field optical microscopy based on microfabricated probes.

    PubMed

    Eckert, R; Freyland, J M; Gersen, H; Heinzelmann, H; Schürmann, G; Noell, W; Staufer, U; De Rooij, N F

    2001-04-01

    We demonstrate high resolution imaging with microfabricated, cantilevered probes, consisting of solid quartz tips on silicon levers. The tips are covered by a 60-nm thick layer of aluminium, which appears to be closed at the apex when investigated by transmission electron microscopy. An instrument specifically built for cantilever probes was used to record images of latex bead projection patterns in transmission as well as single molecule fluorescence. All images were recorded in constant height mode and show optical resolutions down to 32 nm. PMID:11298861

  6. Microfabrication and Applications of Opto-Microfluidic Sensors

    PubMed Central

    Zhang, Daiying; Men, Liqiu; Chen, Qiying

    2011-01-01

    A review of research activities on opto-microfluidic sensors carried out by the research groups in Canada is presented. After a brief introduction of this exciting research field, detailed discussion is focused on different techniques for the fabrication of opto-microfluidic sensors, and various applications of these devices for bioanalysis, chemical detection, and optical measurement. Our current research on femtosecond laser microfabrication of optofluidic devices is introduced and some experimental results are elaborated. The research on opto-microfluidics provides highly sensitive opto-microfluidic sensors for practical applications with significant advantages of portability, efficiency, sensitivity, versatility, and low cost. PMID:22163904

  7. Imaging of relaxation times and microwave field strength in a microfabricated vapor cell

    NASA Astrophysics Data System (ADS)

    Horsley, Andrew; Du, Guan-Xiang; Pellaton, Matthieu; Affolderbach, Christoph; Mileti, Gaetano; Treutlein, Philipp

    2013-12-01

    We present a characterization technique for atomic vapor cells, combining time-domain measurements with absorption imaging to obtain spatially resolved information on decay times, atomic diffusion, and coherent dynamics. The technique is used to characterize a 5-mm-diameter, 2-mm-thick microfabricated Rb vapor cell, with N2 buffer gas, placed inside a microwave cavity. Time-domain Franzen and Ramsey measurements are used to produce high-resolution images of the population (T1) and coherence (T2) lifetimes in the cell, while Rabi measurements yield images of the σ-, π, and σ+ components of the applied microwave magnetic field. For a cell temperature of 90∘C, the T1 times across the cell center are found to be a roughly uniform 265μs, while the T2 times peak at around 350μs. We observe a “skin” of reduced T1 and T2 times around the edge of the cell due to the depolarization of Rb after collisions with the silicon cell walls. Our observations suggest that these collisions are far from being 100% depolarizing, consistent with earlier observations made with Na and glass walls. Images of the microwave magnetic field reveal regions of optimal field homogeneity, and thus coherence. Our technique is useful for vapor cell characterization in atomic clocks, atomic sensors, and quantum information experiments.

  8. Microfabrication of transparent materials using filamented femtosecond laser beams

    NASA Astrophysics Data System (ADS)

    Butkus, S.; Paipulas, D.; Gaižauskas, Eugenijus; KaškelytÄ--, D.; Sirutkaitis, V.

    2014-05-01

    Glass drilling realized with the help of femtosecond lasers attract industrial attention, however, desired tasks may require systems employing high numerical aperture (NA) focusing conditions, low repetition rate lasers and complex fast motion translation stages. Due to the sensitivity of such systems, slight instabilities in parameter values can lead to crack formations, severe fabrication rate decrement and poor quality overall results. A microfabrication system lacking the stated disadvantages was constructed and demonstrated in this report. An f-theta lens was used in combination with a galvanometric scanner, in addition, a water pumping system that enables formation of water films of variable thickness in real time on the samples. Water acts as a medium for filament formation, which in turn decreases the focal spot diameter and increases fluence and axial focal length. This article demonstrates the application of a femtosecond (280fs) laser towards rapid cutting of different transparent materials. Filament formation in water gives rise to strong ablation at the surface of the sample, moreover, the water, surrounding the ablated area, adds increased cooling and protection from cracking. The constructed microfabrication system is capable of drilling holes in thick soda-lime, hardened glasses and sapphire. The fabrication time varies depending on the diameter of the hole and spans from a few to several hundred seconds. Moreover, complex-shape fabrication was demonstrated.

  9. Microcontact printing of self-assembled monolayers: applications in microfabrication

    NASA Astrophysics Data System (ADS)

    Wilbur, James L.; Kumar, Amit; Biebuyck, Hans A.; Kim, Enoch; Whitesides, George M.

    1996-12-01

    This paper describes applications in microfabrication using patterned self-assembled monolayers (SAMs) formed by microcontact printing. Microcontact printing 0957-4484/7/4/028/img1 is a flexible new technique that forms patterned SAMs with regions terminated by different chemical functionalities (and thus different physical and chemical properties), in patterns with 0957-4484/7/4/028/img2 dimensions. Patterns of SAM are formed using an alkanethiol as an `ink', and printing the alkanethiol on a metal support with elastomeric `stamp'. We fabricate the stamp by moulding a silicone elastomer using a master prepared by optical or x-ray microlithography or by other techniques. SAMs of long-chain alkanethiolates on gold and other metals can act as nanometer resists by protecting the supporting metal from corrosion by appropriately formulated etchants: the fabrication of microstructures of gold and silicon demonstrates the utility of patterned SAMs (formed by 0957-4484/7/4/028/img3) as nm resists. Patterned SAMs formed by 0957-4484/7/4/028/img3 can also control the wettability of a surface on the 0957-4484/7/4/028/img2 scale. The organization of liquids in patterned arrays with 0957-4484/7/4/028/img2 dimensions, and the patterned deposition of microcrystals and microcrystal arrays illustrate the use of controlled wettability for microfabrication.

  10. Ball-grid array architecture for microfabricated ion traps

    SciTech Connect

    Guise, Nicholas D. Fallek, Spencer D.; Stevens, Kelly E.; Brown, K. R.; Volin, Curtis; Harter, Alexa W.; Amini, Jason M.; Higashi, Robert E.; Lu, Son Thai; Chanhvongsak, Helen M.; Nguyen, Thi A.; Marcus, Matthew S.; Ohnstein, Thomas R.; Youngner, Daniel W.

    2015-05-07

    State-of-the-art microfabricated ion traps for quantum information research are approaching nearly one hundred control electrodes. We report here on the development and testing of a new architecture for microfabricated ion traps, built around ball-grid array (BGA) connections, that is suitable for increasingly complex trap designs. In the BGA trap, through-substrate vias bring electrical signals from the back side of the trap die to the surface trap structure on the top side. Gold-ball bump bonds connect the back side of the trap die to an interposer for signal routing from the carrier. Trench capacitors fabricated into the trap die replace area-intensive surface or edge capacitors. Wirebonds in the BGA architecture are moved to the interposer. These last two features allow the trap die to be reduced to only the area required to produce trapping fields. The smaller trap dimensions allow tight focusing of an addressing laser beam for fast single-qubit rotations. Performance of the BGA trap as characterized with {sup 40}Ca{sup +} ions is comparable to previous surface-electrode traps in terms of ion heating rate, mode frequency stability, and storage lifetime. We demonstrate two-qubit entanglement operations with {sup 171}Yb{sup +} ions in a second BGA trap.

  11. The Intersection of Flow Cytometry with Microfluidics and Microfabrication

    PubMed Central

    Piyasena, Menake E.; Graves, Steven W.

    2014-01-01

    A modern flow cytometer can analyze and sort particles on a one by one basis at rates of 50,000 particles per second. Flow cytometers can also measure as many as 17 channels of fluorescence, several angles of scattered light, and other non-optical parameters such as particle impedance. More specialized flow cytometers can provide even greater analysis power, such as single molecule detection, imaging, and full spectral collection, at reduced rates. These capabilities have made flow cytometers an invaluable tool for numerous applications including cellular immunophenotyping, CD4+ T-cell counting, multiplex microsphere analysis, high-throughput screening, and rare cell analysis and sorting. Many bio-analytical techniques have been influenced by the advent of microfluidics as a component in analytical tools and flow cytometry is no exception. Here we detail the functions and uses of a modern flow cytometer, review the recent and historical contributions of microfluidics and microfabricated devices to field of flow cytometry, examine current application areas, and suggest opportunities for the synergistic application of microfabrication approaches to modern flow cytometry. PMID:24488050

  12. Microfabricated capillary electrophoresis amino acid chirality analyzer for extraterrestrial exploration

    NASA Technical Reports Server (NTRS)

    Hutt, L. D.; Glavin, D. P.; Bada, J. L.; Mathies, R. A.

    1999-01-01

    Chiral separations of fluorescein isothiocyanate-labeled amino acids have been performed on a microfabricated capillary electrophoresis chip to explore the feasibility of using such devices to analyze for extinct or extant life signs in extraterrestrial environments. The test system consists of a folded electrophoresis channel (19.0 cm long x 150 microns wide x 20 microns deep) that was photolithographically fabricated in a 10-cm-diameter glass wafer sandwich, coupled to a laser-excited confocal fluorescence detection apparatus providing subattomole sensitivity. Using a sodium dodecyl sulfate/gamma-cyclodextrin pH 10.0 carbonate electrophoresis buffer and a separation voltage of 550 V/cm at 10 degrees C, baseline resolution was observed for Val, Ala, Glu, and Asp enantiomers and Gly in only 4 min. Enantiomeric ratios were determined for amino acids extracted from the Murchison meteorite, and these values closely matched values determined by HPLC. These results demonstrate the feasibility of using microfabricated lab-on-a-chip systems to analyze extraterrestrial samples for amino acids.

  13. Microfabricated Chemical Gas Sensors and Sensor Arrays for Aerospace Applications

    NASA Technical Reports Server (NTRS)

    Hunter, Gary W.

    2005-01-01

    Aerospace applications require the development of chemical sensors with capabilities beyond those of commercially available sensors. In particular, factors such as minimal sensor size, weight, and power consumption are particularly important. Development areas which have potential aerospace applications include launch vehicle leak detection, engine health monitoring, and fire detection. Sensor development for these applications is based on progress in three types of technology: 1) Micromachining and microfabrication (Microsystem) technology to fabricate miniaturized sensors; 2) The use of nanocrystalline materials to develop sensors with improved stability combined with higher sensitivity; 3) The development of high temperature semiconductors, especially silicon carbide. This presentation discusses the needs of space applications as well as the point-contact sensor technology and sensor arrays being developed to address these needs. Sensors to measure hydrogen, hydrocarbons, nitrogen oxides (NO,), carbon monoxide, oxygen, and carbon dioxide are being developed as well as arrays for leak, fire, and emissions detection. Demonstrations of the technology will also be discussed. It is concluded that microfabricated sensor technology has significant potential for use in a range of aerospace applications.

  14. Microfabricated Chemical Sensors for Aerospace Fire Detection Applications

    NASA Technical Reports Server (NTRS)

    Hunter, Gary W.; Neudeck, Philip G.; Fralick, Gustave; Thomas, Valarie; Makel, D.; Liu, C. C.; Ward, B.; Wu, Q. H.

    2001-01-01

    The detection of fires on-board commercial aircraft is extremely important for safety reasons. Although dependable fire detection equipment presently exists within the cabin, detection of fire within the cargo hold has been less reliable and susceptible to false alarms. A second, independent method of fire detection to complement the conventional smoke detection techniques, such as the measurement of chemical species indicative of a fire, will help reduce false alarms and improve aircraft safety. Although many chemical species are indicative of a fire, two species of particular interest are CO and CO2. This paper discusses microfabricated chemical sensor development tailored to meet the needs of fire safety applications. This development is based on progress in three types of technology: 1) Micromachining and microfabrication (Microsystem) technology to fabricate miniaturized sensors. 2) The use of nanocrystalline materials to develop sensors with improved stability combined with higher sensitivity. 3) The development of high temperature semiconductors, especially silicon carbide. The individual sensor being developed and their level of maturity will be presented.

  15. A Scalable Microfabricated Ion Trap for Quantum Information Processing

    NASA Astrophysics Data System (ADS)

    Maunz, Peter; Haltli, Raymond; Hollowell, Andrew; Lobser, Daniel; Mizrahi, Jonathan; Rembetski, John; Resnick, Paul; Sterk, Jonathan D.; Stick, Daniel L.; Blain, Matthew G.

    2016-05-01

    Trapped Ion Quantum Information Processing (QIP) relies on complex microfabricated trap structures to enable scaling of the number of quantum bits. Building on previous demonstrations of surface-electrode ion traps, we have designed and characterized the Sandia high-optical-access (HOA-2) microfabricated ion trap. This trap features high optical access, high trap frequencies, low heating rates, and negligible charging of dielectric trap components. We have observed trap lifetimes of more than 100h, measured trap heating rates for ytterbium of less than 40quanta/s, and demonstrated shuttling of ions from a slotted to an above surface region and through a Y-junction. Furthermore, we summarize demonstrations of high-fidelity single and two-qubit gates realized in this trap. Sandia is a multiprogram laboratory operated by Sandia Corporation, a Lockheed Martin Company, for the United States Department of Energy's National Nuclear Security Administration under Contract DE-AC04-94AL85000. This work was supported by the Intelligence Advanced Research Projects Activity (IARPA).

  16. Microfabricated, amperometric, enzyme-based biosensors for in vivo applications.

    PubMed

    Weltin, Andreas; Kieninger, Jochen; Urban, Gerald A

    2016-07-01

    Miniaturized electrochemical in vivo biosensors allow the measurement of fast extracellular dynamics of neurotransmitter and energy metabolism directly in the tissue. Enzyme-based amperometric biosensing is characterized by high specificity and precision as well as high spatial and temporal resolution. Aside from glucose monitoring, many systems have been introduced mainly for application in the central nervous system in animal models. We compare the microsensor principle with other methods applied in biomedical research to show advantages and drawbacks. Electrochemical sensor systems are easily miniaturized and fabricated by microtechnology processes. We review different microfabrication approaches for in vivo sensor platforms, ranging from simple modified wires and fibres to fully microfabricated systems on silicon, ceramic or polymer substrates. The various immobilization methods for the enzyme such as chemical cross-linking and entrapment in polymer membranes are discussed. The resulting sensor performance is compared in detail. We also examine different concepts to reject interfering substances by additional membranes, aspects of instrumentation and biocompatibility. Practical considerations are elaborated, and conclusions for future developments are presented. Graphical Abstract ᅟ. PMID:26935934

  17. Microfabricated Instrumentation for Chemical Sensing in Industrial Process Control

    SciTech Connect

    Ramsey, J. M.

    2000-06-01

    The monitoring of chemical constituents in manufacturing processes is of economic importance to most industries. The monitoring and control of chemical constituents may be of importance for product quality control or, in the case of process effluents, of environmental concern. The most common approach now employed for chemical process control is to collect samples which are returned to a conventional chemical analysis laboratory. This project attempts to demonstrate the use of microfabricated structures, referred to as 'lab-on-a-chip' devices, that accomplish chemical measurement tasks that emulate those performed in the conventional laboratory. The devices envisioned could be used as hand portable chemical analysis instruments where samples are analyzed in the field or as emplaced sensors for continuous 'real-time' monitoring. This project focuses on the development of filtration elements and solid phase extraction elements that can be monolithically integrated onto electrophoresis and chromatographic structures pioneered in the laboratory. Successful demonstration of these additional functional elements on integrated microfabricated devices allows lab-on-a-chip technologies to address real world samples that would be encountered in process control environments. The resultant technology has a broad application to industrial environmental monitoring problems. such as monitoring municipal water supplies, waste water effluent from industrial facilities, or monitoring of run-off from agricultural activities. The technology will also be adaptable to manufacturing process control scenarios. Microfabricated devices integrating sample filtration, solid phase extraction, and chromatographic separation with solvent programming were demonstrated. Filtering of the sample was accomplished at the same inlet with an array of seven channels each 1 {micro}m deep and 18 {micro}m wide. Sample concentration and separation were performed on channels 5 {micro}m deep and 25 {micro

  18. Sub-to super-ambient temperature programmable microfabricated gas chromatography column

    DOEpatents

    Robinson, Alex L.; Anderson, Lawrence F.

    2004-03-16

    A sub- to super-ambient temperature programmable microfabricated gas chromatography column enables more efficient chemical separation of chemical analytes in a gas mixture by combining a thermoelectric cooler and temperature sensing on the microfabricated column. Sub-ambient temperature programming enables the efficient separation of volatile organic compounds and super-ambient temperature programming enables the elution of less volatile analytes within a reasonable time. The small heat capacity and thermal isolation of the microfabricated column improves the thermal time response and power consumption, both important factors for portable microanalytical systems.

  19. Thermal and Structural Analysis of Micro-Fabricated Involute Regenerators

    NASA Astrophysics Data System (ADS)

    Qiu, Songgang; Augenblick, Jack E.

    2005-02-01

    Long-life, high-efficiency power generators based on free-piston Stirling engines are an energy conversion solution for future space power generation and commercial applications. As part of the efforts to further improve Stirling engine efficiency and reliability, a micro-fabricated, involute regenerator structure is proposed by a Cleveland State University-led regenerator research team. This paper reports on thermal and structural analyses of the involute regenerator to demonstrate the feasibility of the proposed regenerator. The results indicate that the involute regenerator has extremely high axial stiffness to sustain reasonable axial compression forces with negligible lateral deformation. The relatively low radial stiffness may impose some challenges to the appropriate installation of the in-volute regenerators.

  20. Development of a hydrogen gas sensor using microfabrication technology

    NASA Technical Reports Server (NTRS)

    Liu, Chung-Chiun; Wu, Qinghai; Stuczynski, Matthew; Madzsar, George C.

    1992-01-01

    Microfabrication and micromachining technologies are used to produce a hydrogen gas sensor based on a palladium-silver film. The sensor uses a heater that is fabricated by diffusing p-type borones into the substrate, forming a resistance heater. A diode for temperature measurement is produced using p-type boron and n-type phosphor diffused into the substrate. A thickness of the palladium-silver film is approximately 300 arcsec. The hydrogen gas sensor employs the proven palladium-silver diode structure and is surrounded by a phosphor doped resistance heater which can be heated up to a temperature of 250 C. Experimental results show that the sensor is capable of operating over a wide range of hydrogen concentration levels between 0-95 percent without any hysteresis effects.

  1. A Microfabricated Involute-Foil Regenerator for Stirling Engines

    NASA Technical Reports Server (NTRS)

    Tew, Roy; Ibrahim, Mounir; Danila, Daniel; Simon, Terry; Mantell, Susan; Sun, Liyong; Gedeon, David; Kelly, Kevin; McLean, Jeffrey; Wood, Gary; Qiu, Songgang

    2007-01-01

    A segmented involute-foil regenerator has been designed, microfabricated and tested in an oscillating-flow rig with excellent results. During the Phase I effort, several approximations of parallel-plate regenerator geometry were chosen as potential candidates for a new microfabrication concept. Potential manufacturers and processes were surveyed. The selected concept consisted of stacked segmented-involute-foil disks (or annular portions of disks), originally to be microfabricated from stainless-steel via the LiGA (lithography, electroplating, and molding) process and EDM (electric discharge machining). During Phase II, re-planning of the effort led to test plans based on nickel disks, microfabricated via the LiGA process, only. A stack of nickel segmented-involute-foil disks was tested in an oscillating-flow test rig. These test results yielded a performance figure of merit (roughly the ratio of heat transfer to pressure drop) of about twice that of the 90% random fiber currently used in small 100 W Stirling space-power convertors in the Reynolds Number range of interest (50-100). A Phase III effort is now underway to fabricate and test a segmented-involute-foil regenerator in a Stirling convertor. Though funding limitations prevent optimization of the Stirling engine geometry for use with this regenerator, the Sage computer code will be used to help evaluate the engine test results. Previous Sage Stirling model projections have indicated that a segmented-involute-foil regenerator is capable of improving the performance of an optimized involute-foil engine by 6-9%; it is also anticipated that such involute-foil geometries will be more reliable and easier to manufacture with tight-tolerance characteristics, than random-fiber or wire-screen regenerators. Beyond the near-term Phase III regenerator fabrication and engine testing, other goals are (1) fabrication from a material suitable for high temperature Stirling operation (up to 850 C for current engines; up to

  2. Microfabricated rubber microscope using soft solid immersion lenses

    NASA Astrophysics Data System (ADS)

    Gambin, Yann; Legrand, Olivier; Quake, Stephen R.

    2006-04-01

    We show here a technique of soft lithography to microfabricate efficient solid immersion lenses (SIL) out of rubber elastomers. The light collection efficiency of a lens system is described by its numerical aperture (NA), and is critical for applications as epifluorescence microscopy [B. Herman, Fluorescence Microscopy (BIOS Scientific, Oxford/Springer, United Kingdom, 1998). While most simple lens systems have numerical apertures less than 1, the lenses described here have NA =1.25. Better performance can be engineered though the use of compound designs; we used this principle to make compound solid immersion lenses (NA=1.32). An important application of these lenses will be as integrated optics for microfluidic devices. We incorporated them into a handheld rubber microscope for microfluidic flow cytometry and imaged single E. Coli cells by fluorescence.

  3. Progress Towards Quantum Simulation Using Micro-fabricated Ion Traps

    NASA Astrophysics Data System (ADS)

    Wright, K.; Ji, G.; Rickerd, C.; Collins, K.; Monroe, C.

    2015-05-01

    We report on current experimental progress towards using a surface electrode trap for quantum simulation. We use a micro-fabricated trap developed collaboratively between the Georgia Tech Research Institute (GTRI) and Honeywell International known as the Ball Grid Array (BGA) trap. This trap features 96 electrodes for fine control of the DC potential as well as a small footprint allowing for tight focusing of interaction lasers. We discuss the experimental system which utilizes the BGA trap, loading of Yb171 ions in this trap, and deterministic loading of chains of five or more ions. We hope to take advantage of the features of this new trap architecture in order to perform a small scale Boson Sampling experiment. This work is performed in collaboration with the GTRI Ion Trap Group and supported by ARO with funding from the IARPA MQCO program, and the AFOSR STTR on Atom Trap Chips.

  4. Rapid microfabrication of transparent materials using filamented femtosecond laser pulses

    NASA Astrophysics Data System (ADS)

    Butkus, S.; Gaižauskas, E.; Paipulas, D.; Viburys, Ž.; Kaškelyė, D.; Barkauskas, M.; Alesenkov, A.; Sirutkaitis, V.

    2014-01-01

    Microfabrication of transparent materials using femtosecond laser pulses has showed good potential towards industrial application. Maintaining pulse energies exceeding the critical self-focusing threshold by more than 100-fold produced filaments that were used for micromachining purposes. This article demonstrates two different micromachining techniques using femtosecond filaments generated in different transparent media (water and glass). The stated micromachining techniques are cutting and welding of transparent samples. In addition, cutting and drilling experiments were backed by theoretical modelling giving a deeper insight into the whole process. We demonstrate cut-out holes in soda-lime glass having thickness up to 1 mm and aspect ratios close to 20, moreover, the fabrication time is of the order of tens of seconds, in addition, grooves and holes were fabricated in hardened 1.1 mm thick glass (Corning Gorilla glass). Glass welding was made possible and welded samples were achieved after several seconds of laser fabrication.

  5. Techniques For Microfabricating Coils For Microelectromechanical Systems Applications

    SciTech Connect

    Woods, R. C.; Powell, A. L.

    2008-01-21

    The advanced technology necessary for building future space exploration vehicles includes microfabricated coils for making possible self-inductances integrated with other passive and active electronic components. Integrated inductances make possible significant improvements in reliability over the traditional arrangement of using external discrete inductances, as well as allowing significant size (volume) reductions (also important in space vehicles). Two possible fabrication techniques (one using proprietary branded 'Foturan' glass, the other using silicon wafer substrates) for microscopic coils are proposed, using electroplating into channels. The techniques have been evaluated for fabricating the planar electrical coils needed for typical microelectromechanical systems applications. There remain problems associated with processing using 'Foturan' glass, but coil fabrication on silicon wafers was successful. Fabrication methods such as these are expected to play an important part in the development of systems and subsystems for forthcoming space exploration missions.

  6. Microfabrication of Fresnel zone plates by laser induced solid ablation

    NASA Astrophysics Data System (ADS)

    Rodrigues, Vanessa R. M.; Thomas, John; Santhosh, Chidangil; Ramachandran, Hema; Mathur, Deepak

    2016-07-01

    A novel and simple single-step method of inscribing optical elements on metal-coated transparent substrates is demonstrated. Laser induced solid ablation (LISA) demands very low laser energies (nJ), as can be amply provided by a femtosecond laser oscillator. Here, LISA is used to write Fresnel zone plates on indium and tungsten coated glass. With up to 100 zones, remarkable agreement is obtained between measured and expected values of the focal length. LISA has enabled attainment of focal spot sizes that are 38% smaller than what would be obtained using conventional lenses of the same numerical aperture. The simplicity with which a high degree of automation can readily be achieved using LISA makes this cost-effective method amenable to a wide variety of applications related to microfabrication of optical elements.

  7. Microfabricated Gas Sensors Demonstrated in Fire and Emission Applications

    NASA Technical Reports Server (NTRS)

    Hunter, Gary W.

    2003-01-01

    A range of microfabricated chemical sensors are being developed to meet the needs of fire detection and emission monitoring in aerospace applications. These sensors have the advantages over traditional technology of minimal size, weight, and power consumption as well as the ability to be placed closer to where the measurements need to be made. Sensor arrays are being developed to address detection needs in environments where multiple species need to be measured. For example, the monitoring of chemical species such as carbon monoxide (CO), carbon dioxide (CO2), hydrocarbons, and other species is important in the detection of fires on airplanes and spacecraft. In contrast, different sensors are necessary for characterizing some aircraft engine designs where the monitoring of nitrogen oxides (NO(x)) and CO is of high interest. Demonstration of both fire and emission microsensor technology was achieved this year in a collaborative effort undertaken by the NASA Glenn Research Center, Case Western Reserve University, and Makel Engineering, Inc.

  8. Microfabricated multi-frequency particle impedance characterization system

    SciTech Connect

    Fuller, C K; Hamilton, J; Ackler, H; Krulevitch, P; Boser, B; Eldredge, A; Becker, F; Yang, J; Gascoyne, P

    2000-03-01

    We have developed a microfabricated flow-through impedance characterization system capable of performing AC, multi-frequency measurements on cells and other particles. The sensor measures both the resistive and reactive impedance of passing particles, at rates of up to 100 particles per second. Its operational bandwidth approaches 10 MHz with a signal-to-noise ratio of approximately 40 dB. Particle impedance is measured at three or more frequencies simultaneously, enabling the derivation of multiple particle parameters. This constitutes an improvement to the well-established technique of DC particle sizing via the Coulter Principle. Human peripheral blood granulocyte radius, membrane capacitance, and cytoplasmic conductivity were measured (r = 4.1 {micro}m, C{sub mem} = 0.9 {micro}F/cm{sup 2}, {sigma}{sub int} = 0.66 S/m) and were found to be consistent with published values.

  9. A Microfabricated Involute-Foil Regenerator for Stirling Engines

    NASA Technical Reports Server (NTRS)

    Tew, Roy; Ibrahim, Mounir; Danila, Daniel; Simon, Terrence; Mantell, Susan; Sun, Liyong; Gedeon, David; Kelly, Kevin; McLean, Jeffrey; Qiu, Songgang

    2007-01-01

    A segmented involute-foil regenerator has been designed, microfabricated and tested in an oscillating-flow rig with excellent results. During the Phase I effort, several approximations of parallel-plate regenerator geometry were chosen as potential candidates for a new microfabrication concept. Potential manufacturers and processes were surveyed. The selected concept consisted of stacked segmented-involute-foil disks (or annular portions of disks), originally to be microfabricated from stainless-steel via the LiGA (lithography, electroplating, and molding) process and EDM. During Phase II, re-planning of the effort led to test plans based on nickel disks, microfabricated via the LiGA process, only. A stack of nickel segmented-involute-foil disks was tested in an oscillating-flow test rig. These test results yielded a performance figure of merit (roughly the ratio of heat transfer to pressure drop) of about twice that of the 90 percent random fiber currently used in small approx.100 W Stirling space-power convertors-in the Reynolds Number range of interest (50 to 100). A Phase III effort is now underway to fabricate and test a segmented-involute-foil regenerator in a Stirling convertor. Though funding limitations prevent optimization of the Stirling engine geometry for use with this regenerator, the Sage computer code will be used to help evaluate the engine test results. Previous Sage Stirling model projections have indicated that a segmented-involute-foil regenerator is capable of improving the performance of an optimized involute-foil engine by 6 to 9 percent; it is also anticipated that such involute-foil geometries will be more reliable and easier to manufacture with tight-tolerance characteristics, than random-fiber or wire-screen regenerators. Beyond the near-term Phase III regenerator fabrication and engine testing, other goals are (1) fabrication from a material suitable for high temperature Stirling operation (up to 850 C for current engines; up to 1200 C

  10. Solid-state microscale lithium batteries prepared with microfabrication processes

    NASA Astrophysics Data System (ADS)

    Song, Jie; Yang, Xi; Zeng, Shuang-Shuang; Cai, Min-Zhen; Zhang, Liang-Tang; Dong, Quan-Feng; Zheng, Ming-Sen; Wu, Sun-Tao; Wu, Qi-Hui

    2009-04-01

    The miniaturization of power sources is important for meeting the requirements of low power, mass and volume for nano- or microelectronics and MEMS devices. In this paper a dexterous microfabrication process was developed for preparing microscale solid-state lithium batteries. The active size of a single microbattery is 500 µm × 500 µm and its thickness is 1.5 µm. LiCoO2 films prepared by RF sputtering, then annealed at moderate temperature (500 °C), were employed as a cathode electrode, and LiPON and Al films were used as a solid electrolyte and an anode electrode, respectively. An individual microbattery delivers a capacity of about 17 nAh at a current of 5 nA at the initial cycles, and can be operated at as high as 40 nA discharge current.

  11. How to Concentrate Genomic Length DNA in a Microfabricated Array

    NASA Astrophysics Data System (ADS)

    Chen, Yu; Abrams, Ezra; Boles, Christian; Pedersen, Jonas; Flyvbjerg, Henrik; Sturm, James; Austin, Robert

    We demonstrate that a microfabricated bump array can concentrate genomic-length DNA molecules efficiently at continuous, high flow velocities, up to 40 ?m/s, if the single-molecule DNA globule has a sufficiently large shear modulus.. Increase in the shear modulus is accomplished by compacting the DNA molecules to minimal coil-size using polyethylene glycol (PEG) derived depletion forces. We map out the sweet spot where concentration occurs as a function of PEG con- centration, flow speed, and bump array parameters using a combination of theoretical analysis and experiment. Purification of DNA from enzymatic reactions for next-generation DNA-sequencing libraries will be an important application of this development.

  12. A review of microfabrication techniques and dielectrophoretic microdevices for particle manipulation and separation

    NASA Astrophysics Data System (ADS)

    Li, M.; Li, W. H.; Zhang, J.; Alici, G.; Wen, W.

    2014-02-01

    The development of lab-on-a-chip (LOC) devices over the past decade has attracted growing interest. LOC devices aim to achieve the miniaturization, integration, automation and parallelization of biological and chemical assays. One of the applications, the ability to effectively and accurately manipulate and separate micro- and nano-scale particles in an aqueous solution, is particularly appealing in biological, chemical and medical fields. Among the technologies that have been developed and implemented in microfluidic microsystems for particle manipulation and separation (such as mechanical, inertial, hydrodynamic, acoustic, optical, magnetic and electrical methodologies), dielectrophoresis (DEP) may prove to be the most popular because of its label-free nature, ability to manipulate neutral bioparticles, analyse with high selectivity and sensitivity, compatibility with LOC devices, and easy and direct interface with electronics. The required spatial electric non-uniformities for the DEP effect can be generated by patterning microelectrode arrays within microchannels, or placing insulating obstacles within a microchannel and curving the microchannels. A wide variety of electrode- and insulator-based DEP microdevices have been developed, fabricated, and successfully employed to manipulate and separate bioparticles (i.e. DNA, proteins, bacteria, viruses, mammalian and yeast cells). This review provides an overview of the state-of-the-art of microfabrication techniques and of the structures of dielectrophoretic microdevices aimed towards different applications. The techniques used for particle manipulation and separation based on microfluidics are provided in this paper. In addition, we also present the theoretical background of DEP.

  13. DETERMINATION OF HETEROGENEOUS ELECTRON TRANSFER RATE CONSTANTS AT MICROFABRICATED IRIDIUM ELECTRODES. (R825511C022)

    EPA Science Inventory

    There has been an increasing use of both solid metal and microfabricated iridium electrodes as substrates for various types of electroanalysis. However, investigations to determine heterogeneous electron transfer rate constants on iridium, especially at an electron beam evapor...

  14. Microfabrication of the UV transparent polymer CYTOP using a conventional pulsed green laser

    NASA Astrophysics Data System (ADS)

    Ogawa, Tatsuya; Hanada, Yasutaka

    2016-03-01

    We report the surface microfabrication of CYTOP, an amorphous UV transparent fluoric polymer, using a conventional pulsed green laser. Fluorine-based polymers have unique characteristics, including high transparency from the deep-UV to the IR wavelengths, chemical stability and low refractive indices, and thus are expected to have a number of industrial applications. However, CYTOP and other fluoric polymers are generally very difficult to microfabricate. Therefore, we have developed a technique for the crack-free surface microfabrication of a CYTOP substrate based on ablation with a pulsed green laser followed by successive wet etching and annealing. In this work, the fundamental surface characteristics of the fabricated area were investigated. Following the surface microfabrication of CYTOP, a three-dimensional biochip was fabricated using a conventional bonding technique to demonstrate that a CYTOP biochip is superior to conventional transparent biochips with regard to the microscopic observation of cell motion.

  15. DEM microfabrication technique and its applications in bioscience and microfluidic systems

    NASA Astrophysics Data System (ADS)

    Chen, Di; Yang, Fan; Tang, Min; Li, Yigui; Zhu, Jun; Zhang, Dacheng

    2001-10-01

    A new LIGA-like microfabrication technique was developed by present authors. DEM (deepetching, electroforming and microreplication) is the abbreviation of three main process steps in this new microfabrication technique. In contrast to LIGA technique, DEM technique has the advantages of lower cost and shorter process period. Microfluidic systems like plastic capillary electrophoresis chips, micro flowmeters and three-dimensional DNA chips were developed using DEM technique. DEM technique offers a new way for fabrication of MEMS and MOEMS components.

  16. Use of atomic force microscopy (AFM) for microfabric study of cohesive soils.

    PubMed

    Sachan, A

    2008-12-01

    Microfabric reflects the imprints of the geologic and stress history of the soil deposit, the depositional environment and weathering history. Many investigators have been concerned with the fundamental problem of how the engineering properties of clay depend on the microfabric, which can be defined as geometric arrangement of particles within the soil mass. It is believed that scanning electron microscopy (SEM) and transmission electron microscopy (TEM) are the only techniques that can reveal particle arrangements of clayey soils directly; however, current research introduces a novel and more advanced technique, atomic force microscopy, to evaluate the microfabric of cohesive materials. The atomic force microscopy has several advantages over SEM/TEM for characterizing cohesive particles at the sub-micrometre range by providing 3D images and 2D images with Z-information used in quantitative measurements of soil microfabric using SPIP software, and having the capability of obtaining images in all environments (ambient air, liquids and vacuums). This paper focuses on the use of atomic force microscopy technique to quantify the microfabric of clayey soils by developing the criteria for average and maximum values of angle of particle orientation within the soil mass using proposed empirical equations for intermediate and extreme microfabrics (dispersed, flocculated). PMID:19094019

  17. A microfabricated scanning confocal optical microscope for in situ imaging

    NASA Astrophysics Data System (ADS)

    Dickensheets, David Lee

    Scanning confocal optical microscopes are well suited for imaging living tissue because of their ability to 'cross section' intact tissue. They are not, however, well suited for imaging tissues in situ. This dissertation describes a new, miniature, mirror scanned, high resolution confocal optical microscope that operates in real time. It is small enough to fit into an endoscope, and may eventually be incorporated into a hypodermic needle. Such a device would provide immediate in-situ tissue assessment at the cellular level and may enable, for example, biopsy without tissue removal. Non-medical applications may include process monitoring and endoscopic inspection. The microfabricated confocal optical scanning microscope, or μCOSM, incorporates single mode optical fiber illumination, silicon torsional scan mirrors, and an off- axis micro diffractive lens. The prototype device is monochromatic, at 633 nm, with a 1.1 mm working distance and 0.25 NA. It achieves a line response of 0.98 μm FWHM, and an axial response of 11.1 μm FWHM. The first part of the dissertation describes the opto- mechanical design of the microscope, which was chosen to be compatible with the microfabrication technologies used for its construction. Then the imaging properties of the off-axis diffractive objective lens are developed, including the aberrations of second and third order which constrain its use. The lens is a surface relief phase grating, and a rigorous electromagnetic analysis is employed to specify the pupil function of the microscope. Then the image forming properties of the μCOSM are derived and compared to experimental results. The second part of the dissertation describes the fabrication of the individual elements of the μCOSM, and their assembly into an imaging instrument. The lens is constructed using electron beam lithography and reactive ion etching of a fused silica substrate. The scanning mirrors for the microscope, which comprise a single crystal silicon plate

  18. Fluid and Cell Transport Through a Microfabricated Flow Chamber.

    NASA Astrophysics Data System (ADS)

    Brody, James Patrick

    We use silicon processing techniques to construct microfabricated fluid flow chambers. Custom designed silicon wafers with feature sizes of 1-10 μm and etch depths from 0.5-5 μm are anodically bonded to Pyrex glass to create a hermetically sealed chamber. A pressure gradient is placed across the chamber to induce bulk fluid flow. Properties of fluid flow and red blood cells are recorded using video microscopy. The human red blood cell is ideal for studying cellular membranes. It is an 8 μm diameter biconcave disc containing a membrane and associated cytoskeleton which surrounds a thick solution of hemoglobin. The material properties of individual red blood cells have been extensively studied in the past using micropipettes. However, we can get statistics on hundreds of red blood cells by fabricating an array of narrow channels 4 mu m x 4 μm in cross-section (the diameter of the smallest capillaries in the human body) and 13 μm long. These narrow channels are followed by an open space. This geometry forces red cells to repeatedly fold and unfold. Using these arrays, we show that the shear modulus of the membrane does not have a unique value, but has a distribution that ranges from 3-12 times 10 ^{-6} N/m. The surprisingly wide distribution is not due to cell size or cell age. It does seem to be correlated with intracellular Ca^ {2+}<=vels, leading us to believe that cell rigidity is controlled by some active process. We also report observations on red blood cells changing their rigidity by factors of fifty over tens of seconds. These microfabricated flow chambers are ideal for studying fluid flow through porous media. We construct custom designed two-dimensional environments with micron size features. These environments can be described by simple analytical theories which also attempt to describe flow through rock. For example, we image viscous imbibition of water into a percolation grid with 5 mu m edges in real time, and measure the permeability as a function

  19. Microfabrication and Test of a Three-Dimensional Polymer Hydro-focusing Unit for Flow Cytometry Applications

    NASA Technical Reports Server (NTRS)

    Yang, Ren; Feeback, Daniel L.; Wang, Wanjun

    2004-01-01

    This paper details a novel three-dimensional (3D) hydro-focusing micro cell sorter for micro flow cytometry applications. The unit was microfabricated by means of SU-8 3D lithography. The 3D microstructure for coaxial sheathing was designed, microfabricated, and tested. Three-dimensional hydro-focusing capability was demonstrated with an experiment to sort labeled tanned sheep erythrocytes (red blood cells). This polymer hydro-focusing microstructure is easily microfabricated and integrated with other polymer microfluidic structures.

  20. Progress Towards Quantum Simulation Using Micro-fabricated Ion Traps

    NASA Astrophysics Data System (ADS)

    Wright, K.; Cao, C.; Ji, G.; Brennan, T.; Monroe, C.

    2014-05-01

    We report our current experimental progress towards using surface electrode traps for quantum simulation. Current progress is being made using a micro-fabricated Satellite trap from GTRI. This trap features two long storage arms which can be used to hold ions in reserve to mitigate the need to load ions via a heated oven in the event of ion loss. This should allow trapping of long ion chains with a substantial decrease in the time needed to recover an ion chain of a given length. The trap has 96 electrodes for fine control of the DC potential needed to create large anharmonic trapping wells. It also features two crossing linear regions for the ordering of mixed ion chains by selective shuttling between the arms of intersecting linear regions of the trap. This should allow us to trap multiple species and explore the advantages of having sympathetic coolant ions. Interspersing these ions through a chain of ions undergoing coherent operations potentially could increase the chain lifetime as well as mitigate certain heating effects. We hope to use these features as the next step in increasing the size of current quantum simulations being done at UMD, which are aimed at exploring quantum phenomena in spin systems. In collaboration with the GTRI QIS Group and supported by grants from the U.S. ARO with funding from the DARPA OLE program, IARPA, and the MURI program; and the NSF Physics Frontier Center at JQI.

  1. Intracellular delivery of molecules using microfabricated nanoneedle arrays.

    PubMed

    Park, Seonhee; Choi, Seong-O; Paik, Seung-joon; Choi, Seungkeun; Allen, Mark; Prausnitz, Mark

    2016-02-01

    Many bioactive molecules have intracellular targets, but have difficulty crossing the cell membrane to reach those targets. To address this difficulty, we fabricated arrays of nanoneedles to gently and simultaneously puncture 10(5) cells and thereby provide transient pathways for transport of molecules into the cells. The nanoneedles were microfabricated by etching silicon to create arrays of nanoneedles measuring 12 μm in height, tapering to a sharp tip less than 30 nm wide to facilitate puncture into cells and spaced 10 μm apart in order to have at least one nanoneedle puncture each cell in a confluent monolayer. These nanoneedles were used for intracellular delivery in two ways: puncture loading, in which nanoneedle arrays were pressed into cell monolayers, and centrifuge loading, in which cells in suspension were spun down onto nanoneedle arrays. The effects on intracellular uptake and cell viability were determined as a function of nanoneedle length and sharpness, puncture force and duration, and molecular weight of the molecule delivered. Under optimal conditions, intracellular uptake was seen in approximately 50 % of cells while maintaining high cell viability. Overall, this study provides a comparative analysis of intracellular delivery using nanoneedle arrays by two different loading methods over a range of operating parameters. PMID:26797026

  2. Microfabricated ratchet structures for concentrating and patterning motile bacterial cells

    NASA Astrophysics Data System (ADS)

    Yub Kim, Sang; Lee, Eun Se; Lee, Ho Jae; Lee, Se Yeon; Kuk Lee, Sung; Kim, Taesung

    2010-09-01

    We present a novel microfabricated concentrator for Escherichia coli that can be a stand-alone and self-contained microfluidic device because it utilizes the motility of cells. First of all, we characterize the motility of E. coli cells and various ratcheting structures that can guide cells to move in a desired direction in straight and circular channels. Then, we combine these ratcheting microstructures with the intrinsic tendency of cells to swim on the right side in microchannels to enhance the concentration rates up to 180 fold until the concentrators are fully filled with cells. Furthermore, we demonstrate that cells can be positioned and concentrated with a constant spacing distance on a surface, allowing spatial patterning of motile cells. These results can be applied to biosorption or biosensor devices that are powered by motile cells because they can be highly concentrated without any external mechanical and electrical energy sources. Hence, we believe that the concentrator design holds considerable potential to be applied for concentrating and patterning other motile microbes and providing a versatile structure for motility study of bacterial cells.

  3. High sensitivity, low power, microfabricated electrochemical sensor for CO

    SciTech Connect

    Neuzil, P.; Kayvani, D.; Maclay, G.J.

    1996-12-31

    CO is a toxic byproduct of incomplete combustion. Improperly vented fireplaces and faulty furnaces cause a estimated 400 deaths in the US each year. The presence of high CO levels may also indicate the presence of a fire. Hence, improved CO detection is of great interest and in the last several years commercial CO detectors have been released. The two most common methods of CO detection in commercial systems for residential use are (1) optical colorometric method, and (2) tin oxide sensor. The colorometric method has the advantage of low power, but the devices tend to give an alarm condition when exposed to low CO levels for a long time period, are difficult to reset, and have a lifetime of about 1 year. The tin oxide sensors have limited stability and high power requirement since the sensor must be heated. There is a need for a stable, sensitive, low power, low cost CO sensor. The authors have developed a planar amperometric sensor for CO detection using microfabrication technology.

  4. Microfabrication of High-Resolution Porous Membranes for Cell Culture

    PubMed Central

    Kim, Monica Y.; Li, David Jiang; Pham, Long K.; Wong, Brandon G.

    2014-01-01

    Microporous membranes are widely utilized in cell biology to study cell-cell signaling and cell migration. However, the thickness and low porosity of commercial track-etched membranes limit the quality of cell imaging and the degree of cell-cell contact that can be achieved on such devices. We employ photolithography-based microfabrication to achieve porous membranes with pore diameter as small as 0.9 μm, up to 40% porosity, and less than 5% variation in pore size. Through the use of a soap release layer, membranes as thin as 1 μm can be achieved. The thin membranes minimally disrupt contrast enhancement optics, thus allowing good quality imaging of unlabeled cells under white light, unlike commercial membranes. In addition, the polymer membrane materials display low autofluorescence even after patterning, facilitating high quality fluorescence microscopy. Finally, confocal imaging suggests that substantial cell-cell contact is possible through the pores of these thin membranes. This membrane technology can enhance existing uses of porous membranes in cell biology as well as enable new types of experiments. PMID:24567663

  5. Microresonator Brillouin laser stabilization using a microfabricated rubidium cell

    NASA Astrophysics Data System (ADS)

    Loh, William; Hummon, Matthew T.; Leopardi, Holly F.; Fortier, Tara M.; Quinlan, Frank; Kitching, John; Papp, Scott B.; Diddams, Scott A.

    2016-06-01

    We frequency stabilize the output of a miniature stimulated Brillouin scattering (SBS) laser to rubidium atoms in a microfabricated cell to realize a laser system with frequency stability at the $10^{-11}$ level over seven decades in averaging time. In addition, our system has the advantages of robustness, low cost and the potential for integration that would lead to still further miniaturization. The SBS laser operating at 1560 nm exhibits a spectral linewidth of 820 Hz, but its frequency drifts over a few MHz on the 1 hour timescale. By locking the second harmonic of the SBS laser to the Rb reference, we reduce this drift by a factor of $10^3$ to the level of a few kHz over the course of an hour. For our combined SBS and Rb laser system, we measure a frequency noise of $4\\times10^4$ $Hz^2/Hz$ at 10 Hz offset frequency which rapidly rolls off to a level of 0.2 $Hz^2/Hz$ at 100 kHz offset. The corresponding Allan deviation is $\\leq2\\times10^{-11}$ for averaging times spanning $10^{-4}$ to $10^3$ s. By optically dividing the signal of the laser down to microwave frequencies, we generate an RF signal at 2 GHz with phase noise at the level of -76 dBc/Hz and -140 dBc/Hz at offset frequencies of 10 Hz and 10 kHz, respectively.

  6. A microfabricated nanocalorimeter: design, characterization, and chemical calibration.

    PubMed

    Xu, Junkai; Reiserer, Ron; Tellinghuisen, Joel; Wikswo, John P; Baudenbacher, Franz J

    2008-04-15

    A microfabricated titration calorimeter having nanowatt sensitivity is presented. The device is achieved by modifying a commercial, suspended-membrane, thin-film thermopile infrared sensor. Chemical reactions are studied by placing a 50.0 nL droplet of one reagent directly on the sensor and injecting nanoliter droplets of a second reagent through a micropipette by means of a pressure-driven droplet injector with 1% reliability in volume delivery. External thermal noise is minimized by a two-layer thermal shielding system. Evaporation is prevented by positioning the micropipette through a tiny hole in a cover glass, sealed by a drop of oil. The device is calibrated using two acid-base reactions: H2SO4 + HEPES buffer, and NaOH + HCl. The measured power sensitivity is 2.90(4) V/W, giving a detection limit of 22 nW. The 1/e time constant for a single injection is 1.1 s. The day-to-day power sensitivity is reproducible to approximately 2%. A computational model of the sensor reproduces the power sensitivity within 10% and the time constant within 20%. For a 50 nL sample and 0.8-1.5 nL titrant injection volumes, the heat uncertainty of 44 nJ corresponds to a 3sigma detection limit of 132 nJ, or the binding energy associated with 2.9 pM of IgG-protein A complex. PMID:18351750

  7. DNA separations in microfabricated devices with automated capillary sample introduction.

    PubMed

    Smith, E M; Xu, H; Ewing, A G

    2001-01-01

    A novel method is presented for automated injection of DNA samples into microfabricated separation devices via capillary electrophoresis. A single capillary is used to electrokinetically inject discrete plugs of DNA into an array of separation lanes on a glass chip. A computer-controlled micromanipulator is used to automate this injection process and to repeat injections into five parallel lanes several times over the course of the experiment. After separation, labeled DNA samples are detected by laser-induced fluorescence. Five serial separations of 6-carboxyfluorescein (FAM)-labeled oligonucleotides in five parallel lanes are shown, resulting in the analysis of 25 samples in 25 min. It is estimated that approximately 550 separations of these same oligonucleotides could be performed in one hour by increasing the number of lanes to 37 and optimizing the rate of the manipulator movement. Capillary sample introduction into chips allows parallel separations to be continuously performed in serial, yielding high throughput and minimal need for operator intervention. PMID:11288906

  8. Continuous-Flow Bioseparation Using Microfabricated Anisotropic Nanofluidic Sieving Structures

    PubMed Central

    Fu, Jianping; Mao, Pan; Han, Jongyoon

    2010-01-01

    The anisotropic nanofluidic filter (nanofilter) array (ANA) is a unique molecular sieving structure for separating biomolecules. Here we describe fabrication of planar and vertical ANA chips and how to perform continuous-flow bioseparation using them. This protocol is most useful for bioengineers that are interested in developing automated multistep chip-based bioanalysis systems and assumes prior cleanroom microfabrication knowledge. The ANA consists of a two-dimensional periodic nanofilter array, and the designed structural anisotropy of the ANA causes different sized- or charged-biomolecules to follow distinct trajectories under applied electric fields, leading to efficient continuous-flow separation. Using microfluidic channels surrounding the ANA, the fractionated biomolecule streams are collected and routed to different fluid channels or reservoirs for convenient sample recovery and downstream bioanalysis. The ANA is physically robust and can be reused repeatedly. Compared to conventional gel-based separation techniques, the ANA offers the potential for faster separation, higher throughput, and more convenient sample recovery. PMID:19876028

  9. Design and microfabrication of a lateral excited gallium arsenide biosensor

    NASA Astrophysics Data System (ADS)

    Bienaime, A.; Liu, L.; Elie-Caille, C.; Leblois, T.

    2012-02-01

    GaAs crystal presents some interesting perspectives for resonant biosensors due to its piezoelectric and good mechanical properties and the opportunity to bio-functionalize the surface. Moreover, GaAs can be micromachined by wet etching in several solutions, which constitutes a batch and low-cost process of fabrication. The lateral field excitation (LFE) is used to generate bulk acoustic waves. The main advantage of LFE is the possibility to measure in liquid media, moreover reduced aging and increased frequency stability are also ensured. In this study, an analytical modelization is used to determine the orientations of the vibrating membrane and the electric field that give satisfactory metrological performances. Electrical performances are discussed as a function of geometrical parameters. A simulation based on a Finite Element Modelization is performed in order to optimize the design of the resonant structure. The microfabrication process of the structure is presented. The choice of etchants is discussed in terms of etching rates and surface textures. Several steps of the fabrication of the sensing area structure are shown and characterized. Finally, the active area is fabricated according to the theoretical and experimental results of this study.

  10. Microfabricated silicon gas chromatographic microchannels: fabrication and performance

    NASA Astrophysics Data System (ADS)

    Matzke, Carolyn M.; Kottenstette, Richard J.; Casalnuovo, Stephen A.; Frye-Mason, Gregory C.; Hudson, Mary L.; Sasaki, Darryl Y.; Manginell, Ronald P.; Wong, C. Channy

    1998-08-01

    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 micrometer wide, 200 to 400 micrometer deep, and 10 cm to 100 cm long. Micro-channels 100 cm long take up as little as 1 cm2 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 dominate 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.

  11. Optimization of dielectrophoretic DNA stretching in microfabricated devices

    PubMed Central

    Sung, Kyung Eun; Burns, Mark A.

    2008-01-01

    We have found that the surface and bulk solution properties in a microfabricated device affect the degree and probability of electrostretching of DNA molecules. Using lambda phage DNA, we found that significantly hydrophilic surfaces between the electrodes decreases the efficiency of stretching. Surfaces treated with higher silane (trimethyl chlorosilane) concentrations performed better presumably due to the decreased non-specific adsorption of DNA on these surfaces compared to their more hydrophilic counterparts. The shape and dimensions of the electrodes also affected the efficiency of stretching. Both lift-off and metal etching methods produced electrodes with random microscopic peaks along the electrode’s edge and were poorly suited for stretching. Annealing the electrodes (450°C for 10 min) removed most of these peaks and allowed for more controlled stretching to be obtained. We also found that thin electrodes (65nm) gave close to a 90% success rate of DNA stretching but stretching with thick electrodes (350nm) produced only a 20% success rate. PMID:16642979

  12. Microfabrication-derived DDS: From batch to individual production.

    PubMed

    Takada, K

    2008-06-01

    As a result of recent advances in microfabrication technology (MFT), microparticles including microcapsules and microspheres can be prepared individually and the disadvantages of the conventional microparticles produced by batch production, i.e. (i) low loading efficiency, (ii) large size variation, and (iii) initial burst release, have been remedied. In addition, all conventional microparticles have the same structure, a spherical shape, so they have only one function, sustained release. Threelayer microcapsules (TLMCs) have been designed to address these issues. TLMCs consist of a surface layer, a drug carrying layer, and a basement layer. TLMCs have sustained release as well as adhesiveness and targeting functions. TLMCs are prepared using ink-jet printer nozzle technology. The obtained TLMCs are used for the oral delivery of peptide/protein drugs and long-term sustained-release injection preparation. In addition, self-dissolving micropiles (SDMPs) can be individually produced by MFT as a percutaneous preparation. MFT allows biopharmaceutical drugs like insulin, erythropoietin, and growth hormone to be absorbed through the skin. Thus, advances in MFT have accelerated the development of pharmaceutical technology. PMID:22504567

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

    SciTech Connect

    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.

  14. Microfabricated alkali vapor cell with anti-relaxation wall coating

    SciTech Connect

    Straessle, R.; Pétremand, Y.; Briand, D.; Rooij, N. F. de; Pellaton, M.; Affolderbach, C.; Mileti, G.

    2014-07-28

    We present a microfabricated alkali vapor cell equipped with an anti-relaxation wall coating. The anti-relaxation coating used is octadecyltrichlorosilane and the cell was sealed by thin-film indium-bonding at a low temperature of 140 °C. The cell body is made of silicon and Pyrex and features a double-chamber design. Depolarizing properties due to liquid Rb droplets are avoided by confining the Rb droplets to one chamber only. Optical and microwave spectroscopy performed on this wall-coated cell are used to evaluate the cell's relaxation properties and a potential gas contamination. Double-resonance signals obtained from the cell show an intrinsic linewidth that is significantly lower than the linewidth that would be expected in case the cell had no wall coating but only contained a buffer-gas contamination on the level measured by optical spectroscopy. Combined with further experimental evidence this proves the presence of a working anti-relaxation wall coating in the cell. Such cells are of interest for applications in miniature atomic clocks, magnetometers, and other quantum sensors.

  15. Fractionation of Long DNA Molecules in Microfabricated Arrays

    NASA Astrophysics Data System (ADS)

    Bakajin, Olgica; Duke, T. A. J.; Chou, C. F.; Tegenfeldt, J.; Chan, S. S.; Austin, R. H.; Cox, E. C.

    2000-03-01

    Novel microfabricated devices promise to accomplish fractionation of megabase DNA quickly, accurately, at low cost, and by using small sample amounts. At the entrance to the device the DNA is concentrated in a thin band either at a barrier via entropic forces, or on a platinum wire via dielectric forces. The DNA is then electrophoretically driven into an array of posts arranged in a hexagonal lattice. The dependence of mobility on the length of the DNA molecule is induced by a periodically changing electric field. Under the field whose direction changes by 120 degrees, the DNA molecules move in a regular fashion: the longer DNA molecules backtrack more and move forward at lower speeds than the shorter ones. This technique allows electric fields as large as 1000 V/cm and, thus reduces separation times of long molecules compared to the presently used technique of pulsed-field gel electrophoresis. While in a gel it takes up to 48 hours of pulsing to resolve T4 (167 kbp) and lambda (48.5 kbp) molecules, in our device it takes less than 10 seconds. In 10 minutes we can separate these molecules by many millimeters. For video clips of DNA in hexagonal arrays go to http://suiling.princeton.edu

  16. Microfabricated Thin Film Impedance Sensor & AC Impedance Measurements

    PubMed Central

    Yu, Jinsong; Liu, Chung-Chiun

    2010-01-01

    Thin film microfabrication technique was employed to fabricate a platinum based parallel-electrode structured impedance sensor. Electrochemical impedance spectroscopy (EIS) and equivalent circuit analysis of the small amplitude (±5 mV) AC impedance measurements (frequency range: 1 MHz to 0.1 Hz) at ambient temperature were carried out. Testing media include 0.001 M, 0.01 M, 0.1 M NaCl and KCl solutions, and alumina (∼3 μm) and sand (∼300 μm) particulate layers saturated with NaCl solutions with the thicknesses ranging from 0.6 mm to 8 mm in a testing cell, and the results were used to assess the effect of the thickness of the particulate layer on the conductivity of the testing solution. The calculated resistances were approximately around 20 MΩ, 4 MΩ, and 0.5 MΩ for 0.001 M, 0.01 M, and 0.1 M NaCl solutions, respectively. The presence of the sand particulates increased the impedance dramatically (6 times and 3 times for 0.001 M and 0.1 M NaCl solutions, respectively). A cell constant methodology was also developed to assess the measurement of the bulk conductivity of the electrolyte solution. The cell constant ranged from 1.2 to 0.8 and it decreased with the increase of the solution thickness. PMID:22219690

  17. Protocol for Identifying Fossil Biofilm Microfabrics in Archean and Martian Sedimentary Rocks

    NASA Astrophysics Data System (ADS)

    Bontognali, T. R. R.; McKenzie, J. A.; Vasconcelos, C.

    2014-12-01

    Microbial communities commonly live and grow in aggregates called biofilm. This slimy material is composed of exopolymeric substances (EPS) secreted from the microbial cell to the surrounding environment. Certain biofilms show internal microscopic fabrics, as for example, regularly shaped alveolar structures. These microfabrics are often considered as artifacts due to the dehydration steps required for scanning electron microscopy. However, recent studies have demonstrated that some microfabrics are not artifacts but actual structures, whose architecture is controlled by the microorganisms. These findings, mainly achieved for medical purposes, may have yet unconsidered implications for the search of early life on Earth and on Mars. Indeed, evidence exists that the microfabrics can be mineralized during early diagenesis, preserving fossil imprints of the original biofilm throughout the geological record. Here, we present the results of microscopic investigations of ancient sediments of various age, composition and metamorphic degree that contain microfabrics that we interpret as fossil biofilms. We compile a list of criteria that need to be evaluated before excluding that the putative fossil biofilms may be artifacts due to sample preparation or late stage contamination of the studied rocks. Additionally, we compare these microfabrics to those produced by pure cultures of microorganism grown in the laboratory, as well as microfabrics present in microbial mats that develop in modern evaporitic environments. Finally, we discuss the hypothesis - and the evidence that already exists in its support - that the micrometric size and the morphology of the EPS fabrics is specific to the organism and the genome concerned. By establishing a linkage between specific microbes and the architecture of the mineralized microfabrics, it may be possible to gain precise taxonomic information on early life, as well as to establish a new type of morphological biosignature to be searched

  18. Research of the new optical diffractive super-resolution element of the two-photon microfabrication

    NASA Astrophysics Data System (ADS)

    Wei, Peng; Zhu, Yu; Duan, Guanghong

    2006-11-01

    The new optical diffractive superresolution element (DSE) is being applied to improve the microfabrication radial superresolution in the two-photon three-dimension (3D) microfabrication system, which appeared only a few years ago and can provide the ability to confine photochemical and physical reactions to the order of laser wavelength in three dimensions. The design method of the DSE is that minimizing M if the lowest limit S l of the S and the highest limit G u of the G is set, where Liu [1] explained the definition of the S, M and G. Simulation test result proved that the microfabrication radial superresolution can be improved by the new optical DSE. The phenomenon can only be interpreted as the intensity of high-order and side of the zero-order diffraction peaks have been clapped under the twophoton absorption (TPA) polymerization threshold. In a word the polymerized volume can be chosen because the S l and the G u is correspondingly adjustable, even if the laser wavelength, objective lens and the photosensitive resin is fixed for a given two-photon microfabrication system. That means the radial superresolution of the two-photon microfabrication can be chosen.

  19. Microfabricated electrochemical detector for high-performance liquid chromatography.

    PubMed

    Ogburn, Evan T; Dziewatkoski, Michael; Moles, Don; Johnson, Jay M; Heineman, William R

    2011-09-15

    A microfabricated electrochemical cell has been developed as a disposable detector for flow injection analysis (FIA) and high-performance liquid chromatography (HPLC). The simplicity of the fabrication process allows this detector to be used as a low-cost, disposable device that can be replaced easily if its performance degrades rather than disassembling the detector and polishing the electrode surface, which is the usual procedure. The detector consists of thin film-metal electrodes-platinum working electrode, platinum auxiliary electrode, and silver/silver chloride coated on Pt reference electrode-deposited on a polyimide substrate with a locking layer of chromium in between. A microfluidic cover made of polyimide directs the solution flow across the electrodes. The detector was evaluated with FIA of ferrocyanide and HPLC of ascorbic acid and acetaminophen and a mixture of two pharmaceutical compounds-dextrorphan and levallorphan-with acetaminophen internal standard. The HPLC calibration curves showed good linearity (R(2) > 0.99). Limits of detection were 1 nM for acetaminophen, 1 nM for ascorbic acid, 50 nM for dextrorphan, and 80 nM for levallorphan. When detected with a commercial detector dextrorphan and levallorphan had lower limits of detection, 3 and 5 nM, respectively. Chromatograms of the mixture were comparable to those obtained with a commercial detector. The detector could be used continuously for about 48 h with FIA and about 10-20 h with HPLC after which performance gradually degraded as the AgCl on the reference electrode dissolved causing loss of potential control. PMID:21598939

  20. Microfabrication of hierarchical structures for engineered mechanical materials

    NASA Astrophysics Data System (ADS)

    Vera Canudas, Marc

    Materials found in nature present, in some cases, unique properties from their constituents that are of great interest in engineered materials for applications ranging from structural materials for the construction of bridges, canals and buildings to the fabrication of new lightweight composites for airplane and automotive bodies, to protective thin film coatings, amongst other fields. Research in the growing field of biomimetic materials indicates that the micro-architectures present in natural materials are critical to their macroscopic mechanical properties. A better understanding of the effect that structure and hierarchy across scales have on the material properties will enable engineered materials with enhanced properties. At the moment, very few theoretical models predict mechanical properties of simple materials based on their microstructures. Moreover these models are based on observations from complex biological systems. One way to overcome this challenge is through the use of microfabrication techniques to design and fabricate simple materials, more appropriate for the study of hierarchical organizations and microstructured materials. Arrays of structures with controlled geometry and dimension can be designed and fabricated at different length scales, ranging from a few hundred nanometers to centimeters, in order to mimic similar systems found in nature. In this thesis, materials have been fabricated in order to gain fundamental insight into the complex hierarchical materials found in nature and to engineer novel materials with enhanced mechanical properties. The materials fabricated here were mechanically characterized and compared to simple mechanics models to describe their behavior with the goal of applying the knowledge acquired to the design and synthesis of future engineered materials with novel properties.

  1. Microresonator Brillouin laser stabilization using a microfabricated rubidium cell.

    PubMed

    Loh, William; Hummon, Matthew T; Leopardi, Holly F; Fortier, Tara M; Quinlan, Frank; Kitching, John; Papp, Scott B; Diddams, Scott A

    2016-06-27

    We frequency stabilize the output of a miniature stimulated Brillouin scattering (SBS) laser to rubidium atoms in a microfabricated cell to realize a laser system with frequency stability at the 10-11 level over seven decades in averaging time. In addition, our system has the advantages of robustness, low cost and the potential for integration that would lead to still further miniaturization. The SBS laser operating at 1560 nm exhibits a spectral linewidth of 820 Hz, but its frequency drifts over a few MHz on the 1 hour timescale. By locking the second harmonic of the SBS laser to the Rb reference, we reduce this drift by a factor of 103 to the level of a few kHz over the course of an hour. For our combined SBS and Rb laser system, we measure a frequency noise of 4 × 104 Hz2/Hz at 10 Hz offset frequency which rapidly rolls off to a level of 0.2 Hz2/Hz at 100 kHz offset. The corresponding Allan deviation is ≤2 × 10-11 for averaging times spanning 10-4 to 103 s. By optically dividing the signal of the laser down to microwave frequencies, we generate an RF signal at 2 GHz with phase noise at the level of -76 dBc/Hz and -140 dBc/Hz at offset frequencies of 10 Hz and 10 kHz, respectively. PMID:27410604

  2. The maximum life expectancy for a micro-fabricated diaphragm

    NASA Astrophysics Data System (ADS)

    Cǎlimǎnescu, Ioan; Stan, Liviu-Constantin; Popa, Viorica

    2015-02-01

    Micro-fabricated diaphragms can be used to provide pumping action in microvalve and microfluidic applications. The functionality of the microdiaphragm in a wirelessly actuated micropump plays a major role in low-powered device actuation. In developing micropumps and their components, it is becoming an increasing trend to predict the performance before the prototype is fabricated. Because performance prediction allows for an accurate estimation of yield and lifetime, in addition to developing better understanding of the device while taking into account the details of the device structure and second order effects. Hence avoid potential pitfalls in the device operation in a practical environment. The goal of this research is to determine via FEA the life expectancy for a corrugated circular diaphragm made out of an aluminum alloy. The geometry of the diaphragm is given below being generated within SolidWorks 2010, all the calculations were made using Ansys 13TM . The sound design of a micropump is heavily depending on the lifetime expectancy of the working part of the device which is the diaphragm. This will be subjected on cyclic loading and the fatigue will limit the life of this part. Once the diaphragm is breaking, the micropump is no more able to fulfill its scope. Any micropump manufacturer will then be very concerned on the life expectancy from the fatigue point of view of the diaphragms. The diaphragm circular and corrugated and made of Al alloy, showed a very good behavior from the fatigue point of view, the maximum life expectancy being 1.9 years of continuous functioning with 100 cycles per second. This work showed an simple and forward application of FEA analysis methods in order to estimate the fatigue behavior of corrugated circular microdiaphragms.

  3. A unified scaling model for flow through a lattice of microfabricated posts.

    PubMed

    Srivastava, Nimisha; Din, Changsong; Judson, Andrew; MacDonald, Noel C; Meinhart, Carl D

    2010-05-01

    A scaling model is presented for low Reynolds number viscous flow within an array of microfabricated posts. Such posts are widely used in several lab-on-a-chip applications such as heat pipes, antibody arrays and biomolecule separation columns. Finite element simulations are used to develop a predictive model for pressure driven viscous flow through posts. The results indicate that the flow rate per unit width scales as approximately h1.17g1.33/d0.5 where h is the post height, d post diameter and g is the spacing between the posts. These results compare favorably to theoretical limits. The scaling is extended to capillary pressure driven viscous flows. This unified model is the first report of a scaling that incorporates both viscous and capillary forces in the microfabricated post geometry. The model is consistent with Washburn dynamics and was experimentally validated to within 8% using wetting on microfabricated silicon posts. PMID:20390133

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

    NASA Astrophysics Data System (ADS)

    Kim, Daekeun; So, Peter T. C.

    2010-02-01

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

  5. Microfabrication of Cell-Laden Hydrogels for Engineering Mineralized and Load Bearing Tissues.

    PubMed

    Li, Chia-Cheng; Kharaziha, Mahshid; Min, Christine; Maas, Richard; Nikkhah, Mehdi

    2015-01-01

    Microengineering technologies and advanced biomaterials have extensive applications in the field of regenerative medicine. In this chapter, we review the integration of microfabrication techniques and hydrogel-based biomaterials in the field of dental, bone, and cartilage tissue engineering. We primarily discuss the major features that make hydrogels attractive candidates to mimic extracellular matrix (ECM), and we consider the benefits of three-dimensional (3D) culture systems for tissue engineering applications. We then focus on the fundamental principles of microfabrication techniques including photolithography, soft lithography and bioprinting approaches. Lastly, we summarize recent research on microengineering cell-laden hydrogel constructs for dental, bone and cartilage regeneration, and discuss future applications of microfabrication techniques for load-bearing tissue engineering. PMID:26545742

  6. Microfabric development in dunite during high stress deformation and subsequent recrystallization

    NASA Astrophysics Data System (ADS)

    Trepmann, Claudia; Druiventak, Anthony; Matysiak, Agnes; Renner, Jörg

    2010-05-01

    The microfabric development in dunite is analyzed in non-steady state deformation and annealing experiments, which are designed to simulate earthquake-driven episodic creep in the upper mantle of the oceanic lithosphere at the base of the seismogenic zone. The samples are deformed in a servohydraulically-controlled solid medium deformation apparatus at a temperature of 600°C, a constant strain rate of 10-4s-1 (kick) and a confining pressure of 1.0 GPa. In some experiments deformation is followed by annealing for 15 h to 70 h at zero nominal differential stress, temperatures of 800°C to 1000°C (kick & cook) and 2.0 GPa confining pressure. We use coarse-grained dunite from the Almklovdalen peridotite complex (Western Norway) as starting material. The dunite comprises ca. 90% olivine, <10% orthopyroxene and small amounts of spinel and chlorite. The kick experiments yield maximum differential stress of ca. 1 GPa and < 20% of permanent strain. The resulting microfabrics are analysed by optical and electron microscopic techniques. Intragranular microcracks and micro-shear zones in olivine, which can be crystallographically controlled, developed during deformation. After annealing at 1000°C, the microfabric is characterized by very fine-grained recrystallized olivine grains with an average diameter of ca. 5 µm. The recrystallized grains are arranged along micro-shear zones and occur in aggregates surrounding olivine porphyroclasts. The area fraction of recrystallized grains is varying but generally smaller than 20%. The microfabrics from our experiments compare well with microfabrics observed from naturally deformed peridotites of the Baldissero, Balmuccia and Finero complexes in the Western Alps. Similar olivine recrystallization aggregates in naturally deformed peridotites are frequently interpreted as indicative of deformation by dislocation or diffusion creep. The microfabrics of our kick & cook experiments indicate a development through an initial stage of high

  7. An Integrated Microfabricated Device for Dual Microdialysis and On-line ESI Ion Trap Mass Spectrometry for the Analysis of Complex Biological Samples

    SciTech Connect

    Xiang, Fan; Lin, Yuehe ); Wen, Jian Y.; Matson, Dean W. ); Smith, Richard D. )

    1999-05-01

    A microfabricated dual-microdialysis device in a single integrated microfabricated platform was constructed using laser micromachining techniques for the rapid fractionation and cleanup of complex biological samples. Results suggest the potential for integration of such microfabricated devices with other sample manipulations for the rapid ESI-MS analysis of complex biological samples.

  8. Development of Magnetic Microcalorimeters for Gamma-Ray Spectroscopy

    NASA Astrophysics Data System (ADS)

    Le, L. N.; Hummatov, R.; Hall, J. A.; Cantor, R. C.; Boyd, S. T. P.

    2016-01-01

    Integrating the SQUIDs and sensing coils of magnetic microcalorimeters onto the same die is a promising approach for maximizing flux coupling and signal/noise. However, new challenges in microfabrication must be overcome, because the underlying SQUID devices are sensitive to chemical attack and elevated processing temperatures. In this report, we describe development and details of a microfabrication process for integrated SQUID/sensor gamma-ray magnetic microcalorimeters with electroformed gold absorbers, starting from a modified version of the STAR Cryoelectronics "Delta 1000" Josephson Junction process.

  9. Development of Magnetic Microcalorimeters for Gamma-Ray Spectroscopy

    NASA Astrophysics Data System (ADS)

    Le, L. N.; Hummatov, R.; Hall, J. A.; Cantor, R. C.; Boyd, S. T. P.

    2016-07-01

    Integrating the SQUIDs and sensing coils of magnetic microcalorimeters onto the same die is a promising approach for maximizing flux coupling and signal/noise. However, new challenges in microfabrication must be overcome, because the underlying SQUID devices are sensitive to chemical attack and elevated processing temperatures. In this report, we describe development and details of a microfabrication process for integrated SQUID/sensor gamma-ray magnetic microcalorimeters with electroformed gold absorbers, starting from a modified version of the STAR Cryoelectronics "Delta 1000" Josephson Junction process.

  10. MICROFABRICATED ELECTROCHEMICAL ANALYSIS SYSTEM FOR HEAVY METAL DETECTION. (R825511C047)

    EPA Science Inventory

    A low power, hand-held system has been developed for the measurement of heavy metal ions in aqueous solutions. The system consists of an electrode array sensor, a high performance single chip potentiostat and a microcontroller circuit. The sensor is a microfabricated array of ...

  11. Microfabricated capillary electrophoresis chip and method for simultaneously detecting multiple redox labels

    DOEpatents

    Mathies, Richard A.; Singhal, Pankaj; Xie, Jin; Glazer, Alexander N.

    2002-01-01

    This invention relates to a microfabricated capillary electrophoresis chip for detecting multiple redox-active labels simultaneously using a matrix coding scheme and to a method of selectively labeling analytes for simultaneous electrochemical detection of multiple label-analyte conjugates after electrophoretic or chromatographic separation.

  12. Functional integration of PCR amplification and capillary electrophoresis in a microfabricated DNA analysis device.

    PubMed

    Woolley, A T; Hadley, D; Landre, P; deMello, A J; Mathies, R A; Northrup, M A

    1996-12-01

    Microfabricated silicon PCR reactors and glass capillary electrophoresis (CE) chips have been successfully coupled to form an integrated DNA analysis system. This construct combines the rapid thermal cycling capabilities of microfabricated PCR devices (10 degrees C/s heating, 2.5 degrees C/s cooling) with the high-speed (< 120 s) DNA separations provided by microfabricated CE chips. The PCR chamber and the CE chip were directly linked through a photolithographically fabricated channel filled with hydroxyethylcellulose sieving matrix. Electrophoretic injection directly from the PCR chamber through the cross injection channel was used as an "electrophoretic valve" to couple the PCR and CE devices on-chip. To demonstrate the functionality of this system, a 15 min PCR amplification of a beta-globin target cloned in M13 was immediately followed by high-speed CE chip separation in under 120 s, providing a rapid PCR-CE analysis in under 20 min. A rapid assay for genomic Salmonella DNA was performed in under 45 min, demonstrating that challenging amplifications of diagnostically interesting targets can also be performed. Real-time monitoring of PCR target amplification in these integrated PCR-CE devices is also feasible. Amplification of the beta-globin target as a function of cycle number was directly monitored for two different reactions starting with 4 x 10(7) and 4 x 10(5) copies of DNA template. This work establishes the feasibility of performing high-speed DNA analyses in microfabricated integrated fluidic systems. PMID:8946790

  13. Development of a Web-Based System to Support Self-Directed Learning of Microfabrication Technologies

    ERIC Educational Resources Information Center

    Jou, Min; Wu, Yu-Shiang

    2012-01-01

    Having engineers in microfabrication technologies educated has become much more difficult than having engineers educated in the traditional technologies, and this may be because of the high cost for acquirement of equipment, materials, and infrastructural means (i.e., cleaning rooms), all in addition to the hands-on practices that are often times…

  14. Miniature Trace Gas Detector Based on Microfabricated Optical Resonators

    NASA Technical Reports Server (NTRS)

    Aveline, David C.; Yu, Nan; Thompson, Robert J.; Strekalov, Dmitry V.

    2013-01-01

    While a variety of techniques exist to monitor trace gases, methods relying on absorption of laser light are the most commonly used in terrestrial applications. Cavity-enhanced absorption techniques typically use high-reflectivity mirrors to form a resonant cavity, inside of which a sample gas can be analyzed. The effective absorption length is augmented by the cavity's high quality factor, or Q, because the light reflects many times between the mirrors. The sensitivity of such mirror-based sensors scales with size, generally making them somewhat bulky in volume. Also, specialized coatings for the high-reflectivity mirrors have limited bandwidth (typically just a few nanometers), and the delicate mirror surfaces can easily be degraded by dust or chemical films. As a highly sensitive and compact alternative, JPL is developing a novel trace gas sensor based on a monolithic optical resonator structure that has been modified such that a gas sample can be directly injected into the cavity. This device concept combines ultra-high Q optical whispering gallery mode resonators (WGMR) with microfabrication technology used in the semiconductor industry. For direct access to the optical mode inside a resonator, material can be precisely milled from its perimeter, creating an open gap within the WGMR. Within this open notch, the full optical mode of the resonator can be accessed. While this modification may limit the obtainable Q, calculations show that the reduction is not significant enough to outweigh its utility for trace gas detection. The notch can be milled from the high- Q crystalline WGMR with a focused ion beam (FIB) instrument with resolution much finer than an optical wavelength, thereby minimizing scattering losses and preserving the optical quality. Initial experimental demonstrations have shown that these opened cavities still support high-Q whispering gallery modes. This technology could provide ultrasensitive detection of a variety of molecular species in an

  15. Microfabrication and Test of a Three-Dimensional Polymer Hydro-focusing Unit for Flow Cytometry Applications

    NASA Technical Reports Server (NTRS)

    Yang, Ren; Feeback, Daniel L.; Wang, Wan-Jun

    2005-01-01

    This paper details a novel three-dimensional (3D) hydro-focusing micro cell sorter for micro flow cytometry applications. The unit was microfabricated by means of SU-8 3D lithography. The 3D microstructure for coaxial sheathing was designed, microfabricated, and tested. Three-dimensional hydrofocusing capability was demonstrated with an experiment to sort labeled tanned sheep erythrocytes (red blood cells). This polymer hydro-focusing microstructure is easily microfabricated and integrated with other polymer microfluidic structures. Keywords: SU-8, three-dimensional hydro-focusing, microfluidic, microchannel, cytometer

  16. Microfabrication and Test of a Three-Dimensional Polymer Hydro-Focusing Unit for Flow Cytometry Applications

    NASA Technical Reports Server (NTRS)

    Yang, Ren; Feedback, Daniel L.; Wang, Wanjun

    2004-01-01

    This paper details a novel three-dimensional (3D) hydro-focusing micro cell sorter for micro flow cytometry applications. The unit was micro-fabricated by means of SU-8 3D lithography. The 3D microstructure for coaxial sheathing was designed, micro-fabricated, and tested. Three-dimensional hydrofocusing capability was demonstrated with an experiment to sort labeled tanned sheep erythrocytes (red blood cells). This polymer hydro-focusing microstructure is easily micro-fabricated and integrated with other polymer microfluidic structures.

  17. Magnetized Plasma for Reconfigurable Subdiffraction Imaging

    SciTech Connect

    Zhang Shuang; Xiong Yi; Bartal, Guy; Yin Xiaobo; Zhang Xiang

    2011-06-17

    We show that magnetized plasma with appropriately designed parameters supports nearly diffractionless propagation of electromagnetic waves along the direction of the applied magnetic field, arising from their unbounded equifrequency contour in the magnetized plasma. Such a unique feature can be utilized to construct subdiffraction imaging devices, which is confirmed by detailed numerical investigations. Subdiffraction imaging devices based on magnetic plasma do not require microfabrication normally entailed by construction of metamaterials; more importantly, they can be dynamically reconfigured by tuning the applied magnetic field or the plasma density, and therefore they represent a facile and powerful route for imaging applications.

  18. MAGNETS

    DOEpatents

    Hofacker, H.B.

    1958-09-23

    This patent relates to nmgnets used in a calutron and more particularly to means fur clamping an assembly of magnet coils and coil spacers into tightly assembled relation in a fluid-tight vessel. The magnet comprises windings made up of an assembly of alternate pan-cake type coils and spacers disposed in a fluid-tight vessel. At one end of the tank a plurality of clamping strips are held firmly against the assembly by adjustable bolts extending through the adjacent wall. The foregoing arrangement permits taking up any looseness which may develop in the assembly of coils and spacers.

  19. Microfabricated chip-scale rubidium plasma light source for miniature atomic clocks.

    PubMed

    Venkatraman, Vinu; Pétremand, Yves; Affolderbach, Christoph; Mileti, Gaetano; de Rooij, Nico F; Shea, Herbert

    2012-03-01

    We present the microfabrication and characterization of a low-power, chip-scale Rb plasma light source, designed for optical pumping in miniature atomic clocks. A dielectric barrier discharge (DBD) configuration is used to ignite a Rb plasma in a micro-fabricated Rb vapor cell on which external indium electrodes were deposited. The device is electrically driven at frequencies between 1 and 36 MHz, and emits 140 μW of stable optical power while coupling less than 6 mW of electrical power to the discharge cell. Optical powers of up to 15 and 9 μW are emitted on the Rb D2 and D1 lines, respectively. Continuous operation of the light source for several weeks has been demonstrated, showing its capacity to maintain stable optical excitation of Rb atoms in chip-scale double-resonance atomic clocks. PMID:22481778

  20. Utilization of a digital-versatile-disc pickup head for benchtop laser microfabrication.

    PubMed

    Hautefeuille, Mathieu; Jimenez-Zenteno, Alejandro K; Pérez-Alcázar, Pablo Roberto; Hess-Frieling, Kristopher M; Fernandez-Sanchez, Gerardo; Velazquez, Victor; Grether-Gonzalez, Marcela; Lopez-Moreno, Enrique

    2012-03-10

    Laser microfabrication is now offering interesting solutions to rapidly produce high-resolution photomasks or microstructures. However, most works require expensive commercial lasers and computer numerical control platforms, limiting its use by a large public. In this paper, we report the construction of a simple, custom-made, easily reproducible, automated laser system, based on a DVD optical pickup head. A user-friendly computer interface specifically designed to operate a motorized three-axis platform with micrometric precision controls focus distance and in-plane displacements. Writing performance characterization for both direct ablation and sintering of commercial black toner demonstrated flexibility in tridimensional microfabrication resolution and speed thanks to precise management of laser power and exposure time, with a minimal resolution of 3.1 μm. PMID:22410998

  1. Commercial importance of a unit cell: nanolithographic patenting trends for microsystems, microfabrication, and nanotechnology

    NASA Astrophysics Data System (ADS)

    Eijkel, Kees; Hruby, Jill M.; Kubiak, Glenn D.; Scott, Marion W.; Brokaw, J.; Saile, Volker; Walsh, Steven T.; White, Craig; Walsh, Daniel

    2006-01-01

    Microsystems and nanosystems hold the promise of new and much more effective approaches to both commercial and national security applications. The patenting rate in nanotechnology is exploding, underscoring its commercial and scientific potential. Yet how much of this effort is focused on nanopatterning or a top-down approach to nanofabrication? Nanopatterning in semiconductor microfabrication has already furthered Moore's law, facilitating the transistor as that medium's unit cell. Yet the search for a unit cell for the other two small technical markets (microsystems and the more broadbased nanotechnology) has proven much more elusive. Do nanopatterning advances hold the key to these technology bases finally obtaining a unit cell? We explore the intellectual property base of nanopatterning and how it pertains to semiconductor microfabrication, microsystems, and nanotechnology.

  2. Microfabrication of multi-layered electrodes for dielectrophoresis-based field flow fractionation

    NASA Astrophysics Data System (ADS)

    Mathew, Bobby; Alazzam, Anas; Khashan, Saud A.

    2015-06-01

    This article details the process layout required for realizing a three-dimensional arrangement of electrodes in a microfluidic device for field flow fractionation based on dielectrophoresis. The metal electrodes are placed horizontally, in a stair-case arrangement, and pass through the bulk of the fluid. Several standard microfabrication processes are employed, in realizing this microdevice, including multi-layer photolithography, casting and plasma bonding. Thus the process layout is repeatable and reproducible. The feasibility of this process layout is demonstrated using three electrodes arranged in aforementioned manner; nevertheless, this process can be extended to as many electrodes as desired in the horizontal direction. This process layout can will make applications possible that were not possible till date due to the inability in microfabricating three-dimensional horizontal metal electrodes that run through the entire width of the microchannel.

  3. Assembling a ring-shaped crystal in a microfabricated surface ion trap

    DOE PAGESBeta

    Stick, Daniel Lynn; Tabakov, Boyan; Benito, Francisco; Blain, Matthew; Clark, Craig R.; Clark, Susan; Haltli, Raymond A.; Maunz, Peter; Sterk, Jonathan D.; Tigges, Chris

    2015-09-01

    We report on experiments with a microfabricated surface trap designed for confining a chain of ions in a ring. Uniform ion separation over most of the ring is achieved with a rotationally symmetric design and by measuring and suppressing undesired electric fields. After reducing stray fields, the ions are confined primarily by a radio-frequency pseudopotential and their mutual Coulomb repulsion. As a result, approximately 400 40Ca+ ions with an average separation of 9 μm comprise the ion crystal.

  4. Selective Detection of Sulfur Derivatives Using Microfabricated Tuning Fork-Based Sensors

    PubMed Central

    Rai, Anant; Tsow, Francis; Nassirpour, Sanam; Bankers, Jeffrey; Spinatsch, Martina; He, M. Pete; Forzani, Erica; Tao, N. J.

    2009-01-01

    The paper describes an integtrated sensor system that can selectively and reversibly detect sulfur derivatives in the presence of interferent molecules. This is accomplished by integrating analyte-specific sensing materials with optimized filter materials. Microfabricated quartz tuning fork arrays are used to provide fast, accurate and low-cost transduction of the analyte binding events into electronic signals. The concept is demonstrated for detection of three sulfur derivatives – dimethyl disulfide, ethanethiol and methylsulfide. PMID:20160943

  5. NIST on a Chip: Realizing SI units with microfabricated alkali vapour cells

    NASA Astrophysics Data System (ADS)

    Kitching, J.; Donley, E. A.; Knappe, S.; Hummon, M.; Dellis, A. T.; Sherman, J.; Srinivasan, K.; Aksyuk, V. A.; Li, Q.; Westly, D.; Roxworthy, B.; Lal, A.

    2016-06-01

    We describe several ways in which microfabricated alkali atom vapour cells might potentially be used to accurately realize a variety of International System (SI) units, including the second, the meter, the kelvin, the ampere, and the volt, in a compact, low-cost “chip-scale” package. Such instruments may allow inexpensive in-situ calibrations at the user's location or widespread integration of accurate references into instrumentation and systems.

  6. Microfabricated phenol biosensors based on screen printing of tyrosinase containing carbon ink

    SciTech Connect

    Wang, J.; Chen, Q.

    1995-05-01

    Phenol biosensor strips were microfabricated by screen-printing of tyrosinase containing carbon inks. The ability of the enzyme to tolerate the 2-hour firing process (at 110{degrees}C) is attributed to its organic phase activity. The resulting strips offer unmediated detection of phenolic compounds down to the 1 x 10{sup {minus}7} M level. Direct assays of untreated drinking - and groundwater samples indicate great promise for field screening of phenolic compounds.

  7. Micro-fabricated polydimethyl siloxane (PDMS) surfaces regulate the development of marine microbial biofilm communities.

    PubMed

    Ling, Gee Chong; Low, Min Hui; Erken, Martina; Longford, Sharon; Nielsen, Shaun; Poole, Andrew J; Steinberg, Peter; McDougald, Diane; Kjelleberg, Staffan

    2014-01-01

    This study explored an antifouling (AF) concept based on deployment of microfabricated polydimethyl siloxane (PDMS) surfaces with 1-10 μm periodicity corrugated topographies in temperate marine waters. The effect of the surfaces on the development of microbial biofilms over 28 days and during different seasons, including both summer and winter, was examined using confocal laser scanning microscopy (CLSM) as well as terminal restriction fragment (T-RF) analysis for phylogenetic fingerprinting. The microscale topography significantly impacted biofilm development by altering the attachment pattern and reducing microcolony formation on the 1, 2 and 4 μm PDMS surfaces. Also, field deployments over 28 days showed a significant reduction in biovolume on the 4 and 10 μm PDMS surfaces despite altered environmental conditions. The microfabricated PDMS surfaces further significantly impacted on the community composition of the biofilms, as revealed by changes in T-RF profiles, at different stages of development. Moreover, altered biofilm resistance was demonstrated by exposing pre-established biofilms on 10 μm micro-fabricated surfaces to enhanced flagellate predation by a heterotrophic protist, Rhynchomonas nasuta. Pronounced changes in the overall marine microbial biofilm development as well as community composition warrant exploring substratum modification for marine AF applications. PMID:24558964

  8. A microfabricated electron-tunneling accelerometer as a directional underwater acoustic sensor

    SciTech Connect

    Rockstad, H.K.; Kenny, T.W.; Kelly, P.J.; Gabrielson, T.B.

    1996-04-01

    Microfabricated accelerometers have been developed for a wide variety of applications; however, the principal commercial focus has been on signal detection in the milli-g to tens or hundreds of g accelerations. The development of a microfabricated device to detect accelerations in the 10 to 100 nano-g range is a substantial technological challenge because of the conflict between the required increase in mass (and reduction in suspension stiffness) and the small volume. In an underwater sensor, designed to be nearly neutrally buoyant, there are additional restrictions on the packaging of the sensor with regard to overall density, resistance to hydrostatic pressure, and flexibility of power and signal leads. The design goal of this project is to demonstrate a two-axis sensor in an 8 cm{sup 3} (and 8 gram) package capable of immersion to 600 meters. The sensor must have a self noise below 100 nano-g per root hertz from 5 to 1000 Hz. Several of these requirements have been demonstrated with an accelerometer structure based on electron tunneling and microfabricated from single-crystal silicon. The electron-tunneling transduction mechanism provides an inherently large transduction constant (although at the expense of requiring closed-loop control) and is readily adapted to batch fabrication in silicon. {copyright} {ital 1996 American Institute of Physics.}

  9. Microfabrication of Super Absorbent Polymer Structure Using Nanoimprinting and Swelling Process

    NASA Astrophysics Data System (ADS)

    Inaba, Tomomi; Kano, Tomonori; Miki, Norihisa

    2013-06-01

    Micro-fabrication technologies have been extensively studied to achieve smaller sizes and higher aspect ratios. When the features have sizes of a couple of micrometers or below, nano-imprinting can be an effective method for micro-fabrication at low cost. However, it is difficult to achieve aspect ratio greater than 1. In this research, we propose micro fabrication of super absorbent polymer (SAP) as a new material for micro devices. SAP swells by adding deionized water, which can be used as a post patterning process to enhance the aspect ratio of micro structures. Micropatterning of SAP must be conducted under thoroughly dry conditions and we used nano-imprinting processes. We successfully augmented an aspect ratio of the nano-imprinted micro holes of SAP from 0.65 to 1.2 by the swelling process. The proposed patterning and swelling process of SAP can be applicable to micro-fabricate high-aspect-ratio structures at low cost for high performance lab-on-a-chip.

  10. Direct visualization of clay microfabric signatures driving organic matter preservation in fine-grained sediment

    NASA Astrophysics Data System (ADS)

    Curry, Kenneth J.; Bennett, Richard H.; Mayer, Lawrence M.; Curry, Ann; Abril, Maritza; Biesiot, Patricia M.; Hulbert, Matthew H.

    2007-04-01

    We employed direct visualization of organic matter (OM) sequestered by microfabric signatures in organo-clay systems to study mechanisms of OM protection. We studied polysaccharides, an abundant class of OM in marine sediments, associated with the nano- and microfabric of clay sediment using a novel application of transmission electron microscopy, histochemical staining (periodic acid-thiosemicarbazide-silver proteinate), and enzymatic digestion techniques. We used two experimental organo-clay sediment environments. First, laboratory-consolidated sediment with 10% chitin (w/w) added was probed for chitin before and after digestion with chitinase. Second, fecal pellets from the polychaete Heteromastus filiformis were used as a natural environment rich in clay and polysaccharides. Sections of this material were probed with silver proteinate for polysaccharides before and after digestion with a mixture of enzymes (amylase, cellulase, chitinase, dextranase, and pectinase). In both environments, chitin or other polysaccharides were found within pores, bridging clay domains, and attached to clay surfaces in undigested samples. Digested samples showed chitin or polysaccharides more closely associated with clay surfaces and in small pores. Our results imply protective roles for both sorption to clay surfaces and encapsulation within clay microfabric signatures.

  11. In situ mechanical characterization of square microfabricated elastomeric membranes using an improved microindentation

    NASA Astrophysics Data System (ADS)

    Liu, Kuo-Kang; Khoo, Hwa Seng; Tseng, Fan-Gang

    2004-02-01

    A testing method has been developed for in situ mechanical characterizations of square microfabricated elastomeric membranes, using a tailored microindentation instrument. Such a depth-sensing microindentation system, incorporated with a long-focal microscope for capturing the side view image, provides accurate load-displacement measurements and complete profiles of deformed membranes. The deformations of square silicon rubber membranes with various thicknesses were examined under different degrees of external central microindentation forces. These membranes were integrated and supported by SU-8 photoresist frames, with openings of 2 mm×2 mm. A theoretical model was applied to quantitatively correlate the membrane elasticity to the measured compliance under such indentation. Through comparing the simulated and experimental results, the average values of Young's modulus for these membranes were reasonably extracted and determined. Viscoelasticity of the membranes used was acknowledged; however, it showed no significant effect on the determination of the Young's modulus of the membranes in the current work. The good agreement between the experimental results and the theoretical analyses demonstrates the successful in situ mechanical characterizations of microfabricated elastomeric films, particularly for the square shape membrane, which is the most common structure or component for microfabricated devices.

  12. Permanent magnet microstructures using dry-pressed magnetic powders

    NASA Astrophysics Data System (ADS)

    Oniku, Ololade D.; Bowers, Benjamin J.; Shetye, Sheetal B.; Wang, Naigang; Arnold, David P.

    2013-07-01

    This paper presents microfabrication methods and performance analysis of bonded powder permanent magnets targeting dimensions ranging from 10 µm to greater than 1 mm. For the structural definition and pattern transfer, a doctor blade technique is used to dry press magnetic powders into pre-etched cavities in a silicon substrate. The powders are secured in the cavities by one of the three methods: capping with a polyimide layer, thermal reflow of intermixed wax-binder particles, or conformal coating with a vapor-deposited parylene-C film. A systematic study of micromagnets fabricated using these methods is conducted using three different types of magnetic powders: 50 µm Nd-Fe-B, 5 µm Nd-Fe-B and 1 µm barium ferrite powder. The isotropic magnets are shown to exhibit intrinsic coercivities (Hci) as high as 720 kA m-1, remanences (Br) up to 0.5 T and maximum energy products (BHmax) up to 30 kJ m-3, depending on the magnetic powder used. Process compatibility experiments demonstrate the potential for the magnets to withstand typical microfabrication chemical exposure and thermal cycles, thereby facilitating their integration into more complex process flows. The remanences are also characterized at elevated temperatures to determine thermal sensitivities and maximum operating temperature ranges.

  13. Micro-fabricated silicon spiral spring based electromagnetic energy harvester

    NASA Astrophysics Data System (ADS)

    Bang, Dong Hyun; Park, Jae Yeong

    2013-06-01

    In this study, an electromagnetic energy harvester using a bulk micromachined silicon spiral spring and a polydimethylsiloxane (PDMS) packaging technique was fabricated and characterized to generate electrical energy from ultra-low ambient vibrations under at vibration accelerations 0.3g. The proposed energy harvester was comprised of a highly-miniaturized neodymium-ironboron (NdFeB) magnet, a silicon spiral spring, a multi-turn copper coil, and a PDMS housing in order to improve its electrical output power and reduce its size/volume. When an external vibration directly moves the mounted magnet as a seismic mass at the center of the spiral spring, the mechanical energy of the moving mass was transformed into electrical energy through the 183 turns of the solenoid copper coil. Silicon spiral springs were used to generate a high electrical output power by maximizing the deflection of the movable mass in response to low-level vibrations. The fabricated energy harvester exhibited a resonant frequency of 36 Hz and an optimal load resistance of 99 Ω. It generated an output power of 29.02 µW and load voltage of 107.3 mV at a vibration acceleration of 0.3g. It also exhibited a power density and normalized power density of 48.37 µW·cm-3 and 537.41 µW·cm-3·g-2, respectively. The total volume of the fabricated energy harvester was 1 cm × 1 cm × 0.6 cm (height).

  14. Current driven dynamics of magnetic domain walls in permalloy nanowires

    NASA Astrophysics Data System (ADS)

    Hayashi, Masamitsu

    The significant advances in micro-fabrication techniques opened the door to access interesting properties in solid state physics. With regard to magnetic materials, geometrical confinement of magnetic structures alters the defining parameters that govern magnetism. For example, development of single domain nano-pillars made from magnetic multilayers led to the discovery of electrical current controlled magnetization switching, which revealed the existence of spin transfer torque. Magnetic domain walls (DWs) are boundaries in magnetic materials that divide regions with distinct magnetization directions. DWs play an important role in the magnetization reversal processes of both bulk and thin film magnetic materials. The motion of DW is conventionally controlled by magnetic fields. Recently, it has been proposed that spin polarized current passed across the DW can also control the motion of DWs. Current in most magnetic materials is spin-polarized, due to spin-dependent scattering of the electrons, and thus can deliver spin angular momentum to the DW, providing a "spin transfer" torque on the DW which leads to DW motion. In addition, owing to the development of micro-fabrication techniques, geometrical confinement of magnetic materials enables creation and manipulation of a "single" DW in magnetic nanostructures. New paradigms for DW-based devices are made possible by the direct manipulation of DWs using spin polarized electrical current via spin transfer torque. This dissertation covers research on current induced DW motion in magnetic nanowires. Fascinating effects arising from the interplay between DWs with spin polarized current will be revealed.

  15. Microfabricated modules for sample handling, sample concentration and flow mixing: application to protein analysis by tandem mass spectrometry.

    PubMed

    Figeys, D; Aebersold, R

    1999-02-01

    The comprehensive analysis of biological systems requires a combination of genomic and proteomic efforts. The large-scale application of current genomic technologies provides complete genomic DNA sequences, sequence tags for expressed genes (EST's), and quantitative profiles of expressed genes at the mRNA level. In contrast, protein analytical technology lacks the sensitivity and the sample throughput for the systematic analysis of all the proteins expressed by a tissue or cell. The sensitivity of protein analysis technology is primarily limited by the loss of analytes, due to adsorption to surfaces, and sample contamination during handling. Here we summarize our work on the development and use of microfabricated fluidic systems for the manipulation of minute amounts of peptides and delivery to an electrospray ionization tandem mass spectrometer. New data are also presented that further demonstrate the potential of these novel approaches. Specifically, we describe the use of microfabricated devices as modules to deliver femtomole amounts of protein digests to the mass spectrometer for protein identification. We also describe the use of a microfabricated module for the generation of solvent gradients at nl/min flow rates for gradient chromatography-tandem mass spectrometry. The use of microfabricated fluidic systems reduces the risk of sample contamination and sample loss due to adsorption to wetted surfaces. The ability to assemble dedicated modular systems and to operate them automatically makes the use of microfabricated systems attractive for the sensitive and large-scale analysis of proteins. PMID:10080083

  16. Magnetic

    NASA Astrophysics Data System (ADS)

    Aboud, Essam; El-Masry, Nabil; Qaddah, Atef; Alqahtani, Faisal; Moufti, Mohammed R. H.

    2015-06-01

    The Rahat volcanic field represents one of the widely distributed Cenozoic volcanic fields across the western regions of the Arabian Peninsula. Its human significance stems from the fact that its northern fringes, where the historical eruption of 1256 A.D. took place, are very close to the holy city of Al-Madinah Al-Monawarah. In the present work, we analyzed aeromagnetic data from the northern part of Rahat volcanic field as well as carried out a ground gravity survey. A joint interpretation and inversion of gravity and magnetic data were used to estimate the thickness of the lava flows, delineate the subsurface structures of the study area, and estimate the depth to basement using various geophysical methods, such as Tilt Derivative, Euler Deconvolution and 2D modeling inversion. Results indicated that the thickness of the lava flows in the study area ranges between 100 m (above Sea Level) at the eastern and western boundaries of Rahat Volcanic field and getting deeper at the middle as 300-500 m. It also showed that, major structural trend is in the NW direction (Red Sea trend) with some minor trends in EW direction.

  17. Microfabricated Modular Scale-Down Device for Regenerative Medicine Process Development

    PubMed Central

    Reichen, Marcel; Macown, Rhys J.; Jaccard, Nicolas; Super, Alexandre; Ruban, Ludmila; Griffin, Lewis D.; Veraitch, Farlan S.; Szita, Nicolas

    2012-01-01

    The capacity of milli and micro litre bioreactors to accelerate process development has been successfully demonstrated in traditional biotechnology. However, for regenerative medicine present smaller scale culture methods cannot cope with the wide range of processing variables that need to be evaluated. Existing microfabricated culture devices, which could test different culture variables with a minimum amount of resources (e.g. expensive culture medium), are typically not designed with process development in mind. We present a novel, autoclavable, and microfabricated scale-down device designed for regenerative medicine process development. The microfabricated device contains a re-sealable culture chamber that facilitates use of standard culture protocols, creating a link with traditional small-scale culture devices for validation and scale-up studies. Further, the modular design can easily accommodate investigation of different culture substrate/extra-cellular matrix combinations. Inactivated mouse embryonic fibroblasts (iMEF) and human embryonic stem cell (hESC) colonies were successfully seeded on gelatine-coated tissue culture polystyrene (TC-PS) using standard static seeding protocols. The microfluidic chip included in the device offers precise and accurate control over the culture medium flow rate and resulting shear stresses in the device. Cells were cultured for two days with media perfused at 300 µl.h−1 resulting in a modelled shear stress of 1.1×10−4 Pa. Following perfusion, hESC colonies stained positively for different pluripotency markers and retained an undifferentiated morphology. An image processing algorithm was developed which permits quantification of co-cultured colony-forming cells from phase contrast microscope images. hESC colony sizes were quantified against the background of the feeder cells (iMEF) in less than 45 seconds for high-resolution images, which will permit real-time monitoring of culture progress in future experiments. The

  18. Microfabricated electrospray emitter arrays with integrated extractor and accelerator electrodes for the propulsion of small spacecraft

    NASA Astrophysics Data System (ADS)

    Dandavino, S.; Ataman, C.; Ryan, C. N.; Chakraborty, S.; Courtney, D.; Stark, J. P. W.; Shea, H.

    2014-07-01

    Microfabricated electrospray thrusters could revolutionize the spacecraft industry by providing efficient propulsion capabilities to micro and nano satellites (1-100 kg). We present the modeling, design, fabrication and characterization of a new generation of devices, for the first time integrating in the fabrication process individual accelerator electrodes capable of focusing and accelerating the emitted sprays. Integrating these electrodes is a key milestone in the development of this technology; in addition to increasing the critical performance metrics of thrust, specific impulse and propulsive efficiency, the accelerators enable a number of new system features such as power tuning and thrust vectoring and balancing. Through microfabrication, we produced high density arrays (213 emitters cm-2) of capillary emitters, assembling them at wafer-level with an extractor/accelerator electrode pair separated by micro-sandblasted glass. Through IV measurements, we could confirm that acceleration could be decoupled from the extraction of the spray—an important element towards the flexibility of this technology. We present the largest reported internally fed microfabricated arrays operation, with 127 emitters spraying in parallel, for a total beam of 10-30 µA composed by 95% of ions. Effective beam focusing was also demonstrated, with plume half-angles being reduced from approximately 30° to 15° with 2000 V acceleration. Based on these results, we predict, with 3000 V acceleration, thrust per emitter of 38.4 nN, specific impulse of 1103 s and a propulsive efficiency of 22% with <1 mW/emitter power consumption.

  19. Quantum information experiments with a micro-fabricated, cryogenic, surface-electrode ion trap

    NASA Astrophysics Data System (ADS)

    Wilson, A. C.; Brown, K. R.; Ospelkaus, C.; Colombe, Y.; Leibfried, D.; Wineland, D. J.

    2011-05-01

    Although the basic components of a quantum information processor using trapped ions have been demonstrated, scaling to large numbers of qubits and operations so that algorithms and simulations of practical importance can be implemented remains a major challenge. This is technically challenging because it requires significant improvements in the precision with which quantum states of ions are prepared, manipulated and measured. Solutions are multi-disciplinary - involving micro-fabrication, cryogenics, integrated photonic devices, as wells as materials and surface science. Here we report progress from experiments that address a range of these issues. We use a micro-fabricated, cryogenic, surface-electrode ion trap, with two closely-spaced independently controlled potential wells. In the first experiment with this new apparatus, we implement a scheme for coupling two ions trapped in separate wells, and demonstrate tunable energy exchange at approximately the single quantum level. A second experiment investigates errors in single qubit gates (rotations) with the use of randomized bench-marking. Although the basic components of a quantum information processor using trapped ions have been demonstrated, scaling to large numbers of qubits and operations so that algorithms and simulations of practical importance can be implemented remains a major challenge. This is technically challenging because it requires significant improvements in the precision with which quantum states of ions are prepared, manipulated and measured. Solutions are multi-disciplinary - involving micro-fabrication, cryogenics, integrated photonic devices, as wells as materials and surface science. Here we report progress from experiments that address a range of these issues. We use a micro-fabricated, cryogenic, surface-electrode ion trap, with two closely-spaced independently controlled potential wells. In the first experiment with this new apparatus, we implement a scheme for coupling two ions trapped

  20. Real-Time Ozone Detection Based on a Microfabricated Quartz Crystal Tuning Fork Sensor

    PubMed Central

    Wang, Rui; Tsow, Francis; Zhang, Xuezhi; Peng, Jhih-Hong; Forzani, Erica S.; Chen, Yongsheng; Crittenden, John C.; Destaillats, Hugo; Tao, Nongjian

    2009-01-01

    A chemical sensor for ozone based on an array of microfabricated tuning forks is described. The tuning forks are highly sensitive and stable, with low power consumption and cost. The selective detection is based on the specific reaction of the polymer with ozone. With a mass detection limit of ∼2 pg/mm2 and response time of 1 second, the sensor coated with a polymer sensing material can detect ppb-level ozone in air. The sensor is integrated into a miniaturized wearable device containing a detection circuit, filtration, battery and wireless communication chip, which is ideal for personal and microenvironmental chemical exposure monitoring. PMID:22346720

  1. Microfabrication of an Implantable silicone Microelectrode array for an epiretinal prosthesis

    SciTech Connect

    Maghribi, M

    2003-06-10

    Millions of people suffering from diseases such as retinitis pigmentosa and macular degeneration are legally blind due to the loss of photoreceptor function. Fortunately a large percentage of the neural cells connected to the photoreceptors remain viable, and electrical stimulation of these cells has been shown to result in visual perception. These findings have generated worldwide efforts to develop a retinal prosthesis device, with the hope of restoring vision. Advances in microfabrication, integrated circuits, and wireless technologies provide the means to reach this challenging goal. This dissertation describes the development of innovative silicone-based microfabrication techniques for producing an implantable microelectrode array. The microelectrode array is a component of an epiretinal prosthesis being developed by a multi-laboratory consortium. This array will serve as the interface between an electronic imaging system and the human eye, directly stimulating retinal neurons via thin film conducting traces. Because the array is intended as a long-term implant, vital biological and physical design requirements must be met. A retinal implant poses difficult engineering challenges due to the size of the intraocular cavity and the delicate retina. Not only does it have to be biocompatible in terms of cytotoxicity and degradation, but it also has to be structurally biocompatible, with regard to smooth edges and high conformability; basically mimicking the biological tissue. This is vital to minimize stress and prevent physical damage to the retina. Also, the device must be robust to withstand the forces imposed on it during fabrication and implantation. In order to meet these biocompatibility needs, the use of non-conventional microfabrication materials such as silicone is required. This mandates the enhancement of currently available polymer-based fabrication techniques and the development of new microfabrication methods. Through an iterative process, devices

  2. Tight focusing of plane waves from micro-fabricated spherical mirrors.

    PubMed

    Goldwin, J; Hinds, E A

    2008-10-27

    We derive a formula for the light field of a monochromatic plane wave that is truncated and reflected by a spherical mirror. Within the scalar field approximation, our formula is valid even for deep mirrors, where the aperture radius approaches the radius of curvature. We apply this result to micro-fabricated mirrors whose size scales are in the range of tens to hundreds of wavelengths, and show that sub-wavelength focusing (full-width at half-maximum intensity) can be achieved. This opens up the possibility of scalable arrays of tightly focused optical dipole traps without the need for high-performance optical systems. PMID:18958062

  3. Characterizing and reducing microfabrication-induced loss in superconducting devices, Part I: Resonators

    NASA Astrophysics Data System (ADS)

    Dunsworth, Andrew; Megrant, A.; Chen, Z.; Quintana, C.; Burkett, B.; Kelly, J.; Barends, R.; Fowler, A.; Jeffrey, E.; White, T.; Sank, D.; Mutus, J.; Campbell, B.; Chen, Y.; Chiaro, B.; Neill, C.; O'Malley, P. J. J.; Roushan, P.; Vainsencher, A.; Wenner, J.; Martinis, J. M.

    Planar and 3D superconducting qubits have previously been shown to be limited by microfabrication induced loss. Using finite element simulations, we have identified a major source of this decoherence in superconducting qubits. Furthermore, we experimentally verified this dominant loss channel using a novel resonator based approach, which we call 'Hydra' resonators. We fully characterized and then substantially reduced this loss channel using these Hydra resonators. I will report on these measurements and their implications on improving the coherence of superconducting qubits. This work is supported by Google inc.

  4. Manipulating cell shape by placing cells into micro-fabricated chambers.

    PubMed

    Chang, Fred; Atilgan, Erdinc; Burgess, David; Minc, Nicolas

    2014-01-01

    Cell shape is an important cellular parameter that influences the spatial organization and function of cells. However, it has often been challenging to study the effects of cell shape because of difficulties in experimentally controlling cell shape in a defined way. We describe here a method of physically manipulating sea urchin cells into specified shapes by inserting them into micro-fabricated chambers of different shapes. This method allows for generation of large systematic and quantitative data sets and may be adaptable for different cell types and contexts. PMID:24633802

  5. Microfabricated nanotopological surfaces for study of adhesion-dependent cell mechanosensitivity.

    PubMed

    Chen, Weiqiang; Sun, Yubing; Fu, Jianping

    2013-01-14

    Cells exhibit high sensitivity and diverse responses to the intrinsic nanotopography of the extracellular matrix through their nanoscale cellular sensing machinery. A simple microfabrication method for precise control and spatial patterning of the local nanoroughness on glass surfaces by using photolithography and reactive ion etching is reported. It is demonstrated that local nanoroughness as a biophysical cue could regulate a diverse array of NIH/3T3 fibroblast behaviors, including cell morphology, adhesion, proliferation, migration, and cytoskeleton contractility. The capability to control and further predict cellular responses to nanoroughness might suggest novel methods for developing biomaterials mimicking nanotopographic structures in vivo for functional tissue engineering. PMID:22887768

  6. Assembling a ring-shaped crystal in a microfabricated surface ion trap

    SciTech Connect

    Stick, Daniel Lynn; Tabakov, Boyan; Benito, Francisco; Blain, Matthew; Clark, Craig R.; Clark, Susan; Haltli, Raymond A.; Maunz, Peter; Sterk, Jonathan D.; Tigges, Chris

    2015-09-01

    We report on experiments with a microfabricated surface trap designed for confining a chain of ions in a ring. Uniform ion separation over most of the ring is achieved with a rotationally symmetric design and by measuring and suppressing undesired electric fields. After reducing stray fields, the ions are confined primarily by a radio-frequency pseudopotential and their mutual Coulomb repulsion. As a result, approximately 400 40Ca+ ions with an average separation of 9 μm comprise the ion crystal.

  7. A microfabricated bio-sensor for erythrocytes deformability and volume distributions analysis

    NASA Astrophysics Data System (ADS)

    Bransky, Avishay; Korin, Natanel; Nemirovski, Yael; Dinnar, Uri

    2007-12-01

    The deformability of erythrocytes is of great importance for oxygen delivery in the microcirculation. Reduced RBC deformability is associated with several types of hemolytic anaemias, malaria, sepsis and diabetes. Aging of erythrocytes is also associated with loss of deformability as well as reduction in cell volume. An automated rheoscope has been developed, utilizing a microfabricated glass flow cell, high speed camera and advanced image-processing software. RBCs suspended in a high viscosity medium were filmed flowing through a microchannel. The system produces valuable data such as velocity profiles of RBCs, spatial distribution within the microchannel, cell volume and deformation index (DI) curves. The variation of DI across the channel height, due to change in shear stress, was measured for the first time. Such DI curves were obtained for normal and Thalassemia RBCs and their diagnostic potential was demonstrated. The spatial distribution and velocity of RBCs and rigid microspheres were measured. Both RBC and rigid spheres showed enhanced inward lateral migration, however the RBCs form a depletion region at the center of flow. The volume and surface area of the flowing cells have been estimated based on a fluid mechanics model and experimental results and fell within the normal range. Hence, the system developed, provides means for examining the behavior of individual RBCs in microchannels, and may serve as a microfabricated diagnostic device for deformability and volume measurements.

  8. Microfabrication of a High-Throughput Nanochannel Delivery/Filtration System

    NASA Technical Reports Server (NTRS)

    Ferrari, Mauro; Liu, Xuewu; Grattoni, Alessandro; Fine, Daniel; Hosali, Sharath; Goodall, Randi; Medema, Ryan; Hudson, Lee

    2011-01-01

    A microfabrication process is proposed to produce a nanopore membrane for continuous passive drug release to maintain constant drug concentrations in the patient s blood throughout the delivery period. Based on silicon microfabrication technology, the dimensions of the nanochannel area, as well as microchannel area, can be precisely controlled, thus providing a steady, constant drug release rate within an extended time period. The multilayered nanochannel structures extend the limit of release rate range of a single-layer nanochannel system, and allow a wide range of pre-defined porosity to achieve any arbitrary drug release rate using any preferred nanochannel size. This membrane system could also be applied to molecular filtration or isolation. In this case, the nanochannel length can be reduced to the nanofabrication limit, i.e., 10s of nm. The nanochannel delivery system membrane is composed of a sandwich of a thin top layer, the horizontal nanochannels, and a thicker bottom wafer. The thin top layer houses an array of microchannels that offers the inlet port for diffusing molecules. It also works as a lid for the nanochannels by providing the channels a top surface. The nanochannels are fabricated by a sacrificial layer technique that obtains smooth surfaces and precisely controlled dimensions. The structure of this nanopore membrane is optimized to yield high mechanical strength and high throughput.

  9. Microfabricated Electrochemical Cell-Based Biosensors for Analysis of Living Cells In Vitro

    PubMed Central

    Wang, Jun; Wu, Chengxiong; Hu, Ning; Zhou, Jie; Du, Liping; Wang, Ping

    2012-01-01

    Cellular biochemical parameters can be used to reveal the physiological and functional information of various cells. Due to demonstrated high accuracy and non-invasiveness, electrochemical detection methods have been used for cell-based investigation. When combined with improved biosensor design and advanced measurement systems, the on-line biochemical analysis of living cells in vitro has been applied for biological mechanism study, drug screening and even environmental monitoring. In recent decades, new types of miniaturized electrochemical biosensor are emerging with the development of microfabrication technology. This review aims to give an overview of the microfabricated electrochemical cell-based biosensors, such as microelectrode arrays (MEA), the electric cell-substrate impedance sensing (ECIS) technique, and the light addressable potentiometric sensor (LAPS). The details in their working principles, measurement systems, and applications in cell monitoring are covered. Driven by the need for high throughput and multi-parameter detection proposed by biomedicine, the development trends of electrochemical cell-based biosensors are also introduced, including newly developed integrated biosensors, and the application of nanotechnology and microfluidic technology. PMID:25585708

  10. In situ collagen assembly for integrating microfabricated three-dimensional cell-seeded matrices

    NASA Astrophysics Data System (ADS)

    Gillette, Brian M.; Jensen, Jacob A.; Tang, Beixian; Yang, Genevieve J.; Bazargan-Lari, Ardalan; Zhong, Ming; Sia, Samuel K.

    2008-08-01

    Microscale fabrication of three-dimensional (3D) extracellular matrices (ECMs) can be used to mimic the often inhomogeneous and anisotropic properties of native tissues and to construct in vitro cellular microenvironments. Cellular contraction of fibrous natural ECMs (such as fibrin and collagen I) can detach matrices from their surroundings and destroy intended geometry. Here, we demonstrate in situ collagen fibre assembly (the nucleation and growth of new collagen fibres from preformed collagen fibres at an interface) to anchor together multiple phases of cell-seeded 3D hydrogel-based matrices against cellular contractile forces. We apply this technique to stably interface multiple microfabricated 3D natural matrices (containing collagen I, Matrigel, fibrin or alginate); each phase can be seeded with cells and designed to permit cell spreading. With collagen-fibre-mediated interfacing, microfabricated 3D matrices maintain stable interfaces (the individual phases do not separate from each other) over long-term culture (at least 3weeks) and support spatially restricted development of multicellular structures within designed patterns. The technique enables construction of well-defined and stable patterns of a variety of 3D ECMs formed by diverse mechanisms (including temperature-, ion- and enzyme-mediated crosslinking), and presents a simple approach to interface multiple 3D matrices for biological studies and tissue engineering.

  11. Automated and Online Characterization of Adherent Cell Culture Growth in a Microfabricated Bioreactor

    PubMed Central

    Jaccard, Nicolas; Macown, Rhys J.; Super, Alexandre; Griffin, Lewis D.; Veraitch, Farlan S.

    2014-01-01

    Adherent cell lines are widely used across all fields of biology, including drug discovery, toxicity studies, and regenerative medicine. However, adherent cell processes are often limited by a lack of advances in cell culture systems. While suspension culture processes benefit from decades of development of instrumented bioreactors, adherent cultures are typically performed in static, noninstrumented flasks and well-plates. We previously described a microfabricated bioreactor that enables a high degree of control on the microenvironment of the cells while remaining compatible with standard cell culture protocols. In this report, we describe its integration with automated image-processing capabilities, allowing the continuous monitoring of key cell culture characteristics. A machine learning–based algorithm enabled the specific detection of one cell type within a co-culture setting, such as human embryonic stem cells against the background of fibroblast cells. In addition, the algorithm did not confuse image artifacts resulting from microfabrication, such as scratches on surfaces, or dust particles, with cellular features. We demonstrate how the automation of flow control, environmental control, and image acquisition can be employed to image the whole culture area and obtain time-course data of mouse embryonic stem cell cultures, for example, for confluency. PMID:24692228

  12. Terahertz Response of a Microfabricated Rod Split-Ring-Resonator Electromagnetic Metamaterial

    NASA Astrophysics Data System (ADS)

    Moser, H. O.; Casse, B. D.; Wilhelmi, O.; Saw, B. T.

    2005-02-01

    The first electromagnetic metamaterials (EM3) produced by microfabrication are reported. They are based on the rod split-ring-resonator design as proposed by Pendry et al. [

    IEEE Trans. Microwave Theory Tech. 47, 2075 (1999)IETMAB0018-948010.1109/22.798002
    ] and experimentally confirmed by Smith et al. [
    Phys. Rev. Lett.PRLTAO0031-9007 84, 4184 (2000)10.1103/PhysRevLett.84.4184
    ] in the GHz frequency range. Numerical simulation and experimental results from far infrared (FIR) transmission spectroscopy support the conclusion that the microfabricated composite material is EM3 in the range 1 2.7 THz. This extends the frequency range in which EM3 are available by about 3 orders of magnitude well into the FIR, thereby widely opening up opportunities to verify the unusual physical implications on electromagnetic theory as well as to build novel electromagnetic and optical devices.

  13. Development of a microfabricated optical bend loss sensor for distributive pressure measurement.

    PubMed

    Wang, Wei-Chih; Ledoux, William R; Huang, Chu-Yu; Huang, Cheng-Sheng; Klute, Glenn K; Reinhall, Per G

    2008-02-01

    A flexible high-resolution sensor capable of measuring the distribution of pressure beneath the foot via a microfabricated optical waveguide system is presented. The uniqueness of the system is in its batch fabrication process, which involves a microfabrication molding technique with polydimethylsiloxane (PDMS) as the optical medium. The sensor manufacturing technique is described in detail, the optical performance of the waveguides is quantified and the effect of using a matching fluid to improve fiber-coupling efficiency is demonstrated. Mechanical loading tests were performed on a 4 x 4 array with a 2-mm spacing between sensing elements. Loading displacement curves were obtained using a 0 to 0.4 mm triangle loading profile. A force of 0.28 N applied to one of the sensing elements produced a displacement of a 0.325 mm and 39% change in the output light intensity. Multiple loadings were conducted to demonstrate the repeatability of the sensor. A force image algorithm with a two-layer neural network system was used to identify four load magnitudes and four different shaped applicators. All four shapes were successfully identified with the neural network. PMID:18269997

  14. Development of Microfabricated Chemical Gas Sensors and Sensor Arrays for Aerospace Applications

    NASA Technical Reports Server (NTRS)

    Hunter, G. W.; Neudeck, P. G.; Fralick, G.; Thomas, V.; Liu, C. C.; Wu, W. H.; Ward, B.; Makel, D.

    2002-01-01

    Aerospace applications require the development of chemical sensors with capabilities beyond those of commercially available sensors. In particular, factors such as minimal sensor size, weight, and power consumption are particularly important. Development areas which have potential aerospace applications include launch vehicle leak detection, engine health monitoring, fire detection, and environmental monitoring. Sensor development for these applications is based on progress in three types of technology: 1) Micromachining and microfabrication (Microsystem) technology to fabricate miniaturized sensors. 2) The use of nanocrystalline materials to develop sensors with improved stability combined with higher sensitivity. 3) The development of high temperature semiconductors, especially silicon carbide. However, due to issues of selectivity and cross-sensitivity, individual sensors are limited in the amount of information that they can provide in environments that contain multiple chemical species. Thus, sensor arrays are being developed to address detection needs in such multi-species environments. This paper discusses the needs of space applications as well as the point-contact sensor technology and sensor arrays being developed to address these needs. Sensors to measure hydrogen, hydrocarbons, hydrazine, nitrogen oxides (NO,), carbon monoxide, oxygen, and carbon dioxide are being developed as well as arrays for leak, fire, and emissions detection. Demonstrations of the technology will also be discussed. It is concluded that microfabricated sensor technology has significant potential for use in a range of aerospace applications.

  15. Development and Application of Microfabricated Chemical Gas Sensors For Aerospace Applications

    NASA Technical Reports Server (NTRS)

    Hunter, G. W.; Neudeck, P. G.; Fralick, G.; Thomas, V.; Liu, C. C.; Wu, Q. H.; Sawayda, M. S.; Jin, A.; Hammond, J.; Makel, D.; Hall, G.

    1990-01-01

    Aerospace applications require the development of chemical sensors with capabilities beyond those of commercially available sensors. In particular, factors such as minimal sensor size, weight, and power consumption are particularly important. Development areas which have potential aerospace applications include launch vehicle leak detection, engine health monitoring and control, and fire detection. Sensor development for these applications is based on progress in three types of technology: 1) Micromachining and microfabrication (Microsystem) technology to fabricate miniaturized sensors. 2) The use of nanocrystalline materials to develop sensors with improved stability combined with higher sensitivity. 3) The development of high temperature semiconductors, especially silicon carbide. Sensor development for each application involves its own challenges in the fields of materials science and fabrication technology. This paper discusses the needs of space applications and the point-contact sensor technology being developed to address these needs. Sensors to measure hydrogen, hydrocarbons, nitrogen oxides (Nox, carbon monoxide, oxygen, and carbon dioxide are being developed. A description is given of each sensor type and its present stage of development. Demonstration and application these sensor technologies will be described. The demonstrations range from use of a microsystem based hydrogen sensor on the Shuttle to engine demonstration of a nanocrystalline based sensor for NO, detection. It is concluded that microfabricated sensor technology has significant potential for use in a range of aerospace applications.

  16. Demonstration of a micro-fabricated hydrogen storage module for micro-power systems.

    PubMed

    Shan, Xi; Payer, Joe H; Wainright, Jesse S; Dudik, Laurie

    2011-01-15

    The objective of this work was to demonstrate a micro-fabricated hydrogen storage module for micro-power systems. Hydrogen storage materials were developed as thin-film inks to be compatible with an integrated manufacturing process. Performance and durability of storage modules were evaluated. Further, applications were demonstrated for a nickel-hydrogen battery and a micro-fabricated hydrogen-air PEM fuel cell. The ink making process, in which polymer binders and solvents were added to the palladium-treated alloys, slightly decreased the storage capacities, but had little effect on the activation properties of the treated alloys. After 5000 absorption/desorption cycles under hydrogen, the hydrogen storage capacities of the thin-film inks remained high. Absorption/desorption behavior of the ink was tested in the environment of a new type nickel-hydrogen battery, in which it would in contact with 26wt% KOH solution, and the ink showed no apparent degradation. Storage modules were used as the successfully as hydrogen source for PEM fuel cell. PMID:20953345

  17. Insights into foraminiferal influences on microfabrics of microbialites at Highborne Cay, Bahamas

    PubMed Central

    Bernhard, Joan M.; Edgcomb, Virginia P.; Visscher, Pieter T.; McIntyre-Wressnig, Anna; Summons, Roger E.; Bouxsein, Mary L.; Louis, Leeann; Jeglinski, Marleen

    2013-01-01

    Microbialites, which are organosedimentary structures formed by microbial communities through binding and trapping and/or in situ precipitation, have a wide array of distinctive morphologies and long geologic record. The origin of morphological variability is hotly debated; elucidating the cause or causes of microfabric differences could provide insights into ecosystem functioning and biogeochemistry during much of Earth’s history. Although rare today, morphologically distinct, co-occurring extant microbialites provide the opportunity to examine and compare microbial communities that may be responsible for establishing and modifying microbialite microfabrics. Highborne Cay, Bahamas, has extant laminated (i.e., stromatolites) and clotted (i.e., thrombolites) marine microbialites in close proximity, allowing focused questions about how community composition relates to physical attributes. Considerable knowledge exists about prokaryotic composition of microbialite mats (i.e., stromatolitic and thrombolitic mats), but little is known about their eukaryotic communities, especially regarding heterotrophic taxa. Thus, the heterotrophic eukaryotic communities of Highborne stromatolites and thrombolites were studied. Here, we show that diverse foraminiferal communities inhabit microbialite mat surfaces and subsurfaces; thecate foraminifera are relatively abundant in all microbialite types, especially thrombolitic mats; foraminifera stabilize grains in mats; and thecate reticulopod activities can impact stromatolitic mat lamination. Accordingly, and in light of foraminiferal impacts on modern microbialites, our results indicate that the microbialite fossil record may reflect the impact of the radiation of these protists. PMID:23716649

  18. Demonstration of a micro-fabricated hydrogen storage module for micro-power systems

    PubMed Central

    Shan, Xi; Payer, Joe H; Wainright, Jesse S; Dudik, Laurie

    2010-01-01

    The objective of this work was to demonstrate a micro-fabricated hydrogen storage module for micro-power systems. Hydrogen storage materials were developed as thin-film inks to be compatible with an integrated manufacturing process. Performance and durability of storage modules were evaluated. Further, applications were demonstrated for a nickel-hydrogen battery and a micro-fabricated hydrogen-air PEM fuel cell. The ink making process, in which polymer binders and solvents were added to the palladium-treated alloys, slightly decreased the storage capacities, but had little effect on the activation properties of the treated alloys. After 5000 absorption/desorption cycles under hydrogen, the hydrogen storage capacities of the thin-film inks remained high. Absorption/desorption behavior of the ink was tested in the environment of a new type nickel-hydrogen battery, in which it would in contact with 26wt% KOH solution, and the ink showed no apparent degradation. Storage modules were used as the successfully as hydrogen source for PEM fuel cell. PMID:20953345

  19. Two-photon polymerization microfabrication of hydrogels: an advanced 3D printing technology for tissue engineering and drug delivery.

    PubMed

    Xing, Jin-Feng; Zheng, Mei-Ling; Duan, Xuan-Ming

    2015-08-01

    3D printing technology has attracted much attention due to its high potential in scientific and industrial applications. As an outstanding 3D printing technology, two-photon polymerization (TPP) microfabrication has been applied in the fields of micro/nanophotonics, micro-electromechanical systems, microfluidics, biomedical implants and microdevices. In particular, TPP microfabrication is very useful in tissue engineering and drug delivery due to its powerful fabrication capability for precise microstructures with high spatial resolution on both the microscopic and the nanometric scale. The design and fabrication of 3D hydrogels widely used in tissue engineering and drug delivery has been an important research area of TPP microfabrication. The resolution is a key parameter for 3D hydrogels to simulate the native 3D environment in which the cells reside and the drug is controlled to release with optimal temporal and spatial distribution in vitro and in vivo. The resolution of 3D hydrogels largely depends on the efficiency of TPP initiators. In this paper, we will review the widely used photoresists, the development of TPP photoinitiators, the strategies for improving the resolution and the microfabrication of 3D hydrogels. PMID:25992492

  20. A microfabricated fringing field capacitive pH sensor with an integrated readout circuit

    NASA Astrophysics Data System (ADS)

    Arefin, Md Shamsul; Bulut Coskun, M.; Alan, Tuncay; Redoute, Jean-Michel; Neild, Adrian; Rasit Yuce, Mehmet

    2014-06-01

    This work presents a microfabricated fringe-field capacitive pH sensor using interdigitated electrodes and an integrated modulation-based readout circuit. The changes in capacitance of the sensor result from the permittivity changes due to pH variations and are converted to frequency shifts using a crossed-coupled voltage controlled oscillator readout circuit. The shift in resonant frequency of the readout circuit is 30.96 MHz for a change in pH of 1.0-5.0. The sensor can be used for the measurement of low pH levels, such as gastric acid, and can be integrated with electronic pills. The measurement results show high repeatability, low noise, and a stable output.

  1. Micro-fabricated mechanical sensors for lateral molecular-force microscopy.

    PubMed

    Vicary, J A; Ulcinas, A; Hörber, J K H; Antognozzi, M

    2011-11-01

    Atomic force microscopy (AFM) has been very successful in measuring forces perpendicular to the sample plane. Here, we present the advantages of turning the AFM cantilever 90° in order for it to be perpendicular to the sample. This rotation leads naturally to the detection of in-plane forces with some extra advantages with respect to the AFM orientation. In particular, the use of extremely small (1μm wide) and soft (k≅10(-5)N/m) micro-fabricated cantilevers is demonstrated by recording their thermal power spectral density in ambient conditions and in liquid. These measurements lead to the complete characterisation of the sensors in terms of their stiffness and resonant frequency. Future applications, which will benefit from the use of this force microscopy technique, are also described. PMID:21939619

  2. A microfabricated fringing field capacitive pH sensor with an integrated readout circuit

    SciTech Connect

    Arefin, Md Shamsul Redoute, Jean-Michel; Rasit Yuce, Mehmet; Bulut Coskun, M.; Alan, Tuncay; Neild, Adrian

    2014-06-02

    This work presents a microfabricated fringe-field capacitive pH sensor using interdigitated electrodes and an integrated modulation-based readout circuit. The changes in capacitance of the sensor result from the permittivity changes due to pH variations and are converted to frequency shifts using a crossed-coupled voltage controlled oscillator readout circuit. The shift in resonant frequency of the readout circuit is 30.96 MHz for a change in pH of 1.0–5.0. The sensor can be used for the measurement of low pH levels, such as gastric acid, and can be integrated with electronic pills. The measurement results show high repeatability, low noise, and a stable output.

  3. Microfabrication, surface modification, and laser guidance techniques to create a neuron biochip*

    PubMed Central

    Pirlo, Russell Kirk; Peng, Xiang; Yuan, Xiaocong; Gao, Bruce Zhi

    2013-01-01

    In this report we illustrate our application of soft lithography-based microfabrication, surface modification, and our unique laser cell-patterning system toward the creation of neuron biochips. We deposited individual forebrain neurons from Day 7 embryonic chicks into two rows of eight in a silicon microstructure aligned over a microelectrode array (MEA). The polydimethylsiloxane (PDMS) membrane with microstructures to confine cells and guide network connectivity was aligned to the electrodes of a MEA. Both the MEA and the PDMS membrane were treated with O2 plasma, Poly-L-Lysine, and Laminin to aid in cell attachment and survival. The primary advantage of our process is that it is quicker and simpler than previous cell-placement methods and may make highly defined neuronal network biochips more practical. PMID:23894235

  4. Note: Development of a microfabricated sensor to measure thermal conductivity of picoliter scale liquid samples

    NASA Astrophysics Data System (ADS)

    Park, Byoung Kyoo; Yi, Namwoo; Park, Jaesung; Kim, Dongsik

    2012-10-01

    This paper presents a thermal analysis device, which can measure thermal conductivity of picoliter scale liquid sample. We employ the three omega method with a microfabricated AC thermal sensor with nanometer width heater. The liquid sample is confined by a micro-well structure fabricated on the sensor surface. The performance of the instrument was verified by measuring the thermal conductivity of 27-picoliter samples of de-ionized (DI) water, ethanol, methanol, and DI water-ethanol mixtures with accuracies better than 3%. Furthermore, another analytical scheme allows real-time thermal conductivity measurement with 5% accuracy. To the best of our knowledge, this technique requires the smallest volume of sample to measure thermal property ever.

  5. A High-Average-Power Free Electron Laser for Microfabrication and Surface Applications

    NASA Technical Reports Server (NTRS)

    Dylla, H. F.; Benson, S.; Bisognano, J.; Bohn, C. L.; Cardman, L.; Engwall, D.; Fugitt, J.; Jordan, K.; Kehne, D.; Li, Z.; Liu, H.; Merminga, L.; Neil, G. R.; Neuffer, D.; Shinn, M.; Sinclair, C.; Wiseman, M.; Brillson, L. J.; Henkel, D. P.; Helvajian, H.; Kelley, M. J.; Nair, Shanti

    1995-01-01

    CEBAF has developed a comprehensive conceptual design of an industrial user facility based on a kilowatt ultraviolet (UV) (160-1000 mm) and infrared (IR) (2-25 micron) free electron laser (FEL) driven by a recirculating, energy recovering 200 MeV superconducting radio frequency (SRF) accelerator. FEL users, CEBAF's partners in the Lase Processing Consortium, including AT&T, DuPont, IBM, Northrop Grumman, 3M, and Xerox, are developing applications such as metal, ceramic, and electronic material micro-fabrication and polymer and metal surface processing, with the overall effort leading to later scale-up to industrial systems at 50-100 kW. Representative applications are described. The proposed high-average-power FEL overcomes limitations of conventional laser sources in available power, cost-effectiveness, tunability, and pulse structure.

  6. Optical properties of microfabricated fully-metal-coated near-field probes in collection mode.

    PubMed

    Descrovi, Emiliano; Vaccaro, Luciana; Aeschimann, Laure; Nakagawa, Wataru; Staufer, Urs; Herzig, Hans-Peter

    2005-07-01

    A study of the optical properties of microfabricated, fully-metal-coated quartz probes collecting longitudinal and transverse optical fields is presented. The measurements are performed by raster scanning the focal plane of an objective, focusing azimuthally and radially polarized beams by use of two metal-coated quartz probes with different metal coatings. A quantitative estimation of the collection efficiencies and spatial resolutions in imaging both longitudinal and transverse fields is made. Longitudinally polarized fields are collected with a resolution approximately 1.5 times higher as compared with transversely polarized fields, and this behavior is almost independent of the roughness of the probe's metal coating. Moreover, the coating roughness is a critical parameter in the relative collection efficiency of the two field orientations. PMID:16053165

  7. Microfabrication of Photo-Cross-Linked Hyaluronan Hydrogels by Single- and Two-Photon Tyramine Oxidation.

    PubMed

    Loebel, Claudia; Broguiere, Nicolas; Alini, Mauro; Zenobi-Wong, Marcy; Eglin, David

    2015-09-14

    Photo-cross-linking of tyramine-substituted hyaluronan (HA-Tyr) hydrogels is demonstrated for the first time. HA-Tyr hydrogels are fabricated via a rapid photosensitized process using visible light illumination. Nontoxic conditions offer photoencapsulation of human mesenchymal stromal cells (hMSCs) with high viability. Macroscopic gels can be formed in less than 10 s, and one- and two-photon photopatterning enable 2D and 3D microfabrication. Different degrees of cross-linking induce different swelling/shrinking, allowing for light-induced microactuation. These new tools are complementary to the previously reported horseradish peroxidase/hydrogen peroxide cross-linking and allow sequential cross-linking of HA-Tyr matrices. PMID:26222128

  8. New perspectives for direct PDMS microfabrication using a CD-DVD laser.

    PubMed

    Hautefeuille, M; Cabriales, L; Pimentel-Domínguez, R; Velázquez, V; Hernández-Cordero, J; Oropeza-Ramos, L; Rivera, M; Carreón-Castro, M P; Grether, M; López-Moreno, E

    2013-12-21

    A simple and inexpensive alternative to high-power lasers for the direct fabrication of microchannels and rapid prototyping of poly-dimethylsiloxane (PDMS) is presented. By focusing the infrared laser beam of a commercial, low-power CD-DVD unit on absorbing carbon micro-cluster additives, highly localized PDMS combustion can be used to etch the polymer, which is otherwise transparent at such wavelengths. Thanks to a precise and automated control of laser conditions, laser-induced incandescence is originated at the material surface and produces high-resolution micropatterns that present properties normally induced with lasers of much greater energies in PDMS: formation of in situ nanodomains, local fluorescence and waveguide patterns. An extensive study of the phenomenon and its performance for PDMS microfabrication are presented. PMID:24172647

  9. Microfabric Vessels for Embryoid Body Formation and Rapid Differentiation of Pluripotent Stem Cells

    PubMed Central

    Sato, Hiroki; Idiris, Alimjan; Miwa, Tatsuaki; Kumagai, Hiromichi

    2016-01-01

    Various scalable three-dimensional culture systems for regenerative medicine using human induced pluripotent stem cells (hiPSCs) have been developed to date. However, stable production of hiPSCs with homogeneous qualities still remains a challenge. Here, we describe a novel and simple embryoid body (EB) formation system using unique microfabricated culture vessels. Furthermore, this culture system is useful for high throughput EB formation and rapid generation of differentiated cells such as neural stem cells (NSCs) from hiPSCs. The period of NSC differentiation was significantly shortened under high EB density culture conditions. Simultaneous mass production of a pure population of NSCs was possible within 4 days. These results indicate that the novel culture system might not only become a unique tool to obtain new insights into developmental biology based on human stem cells, but also provide an important tractable platform for efficient and stable production of NSCs for clinical applications. PMID:27507707

  10. Microfabricated rankine cycle steam turbine for power generation and methods of making the same

    NASA Technical Reports Server (NTRS)

    Frechette, Luc (Inventor); Muller, Norbert (Inventor); Lee, Changgu (Inventor)

    2009-01-01

    In accordance with the present invention, an integrated micro steam turbine power plant on-a-chip has been provided. The integrated micro steam turbine power plant on-a-chip of the present invention comprises a miniature electric power generation system fabricated using silicon microfabrication technology and lithographic patterning. The present invention converts heat to electricity by implementing a thermodynamic power cycle on a chip. The steam turbine power plant on-a-chip generally comprises a turbine, a pump, an electric generator, an evaporator, and a condenser. The turbine is formed by a rotatable, disk-shaped rotor having a plurality of rotor blades disposed thereon and a plurality of stator blades. The plurality of stator blades are interdigitated with the plurality of rotor blades to form the turbine. The generator is driven by the turbine and converts mechanical energy into electrical energy.

  11. A Microfabricated Segmented-Involute-Foil Regenerator for Enhancing Reliability and Performance of Stirling Engines

    NASA Technical Reports Server (NTRS)

    Ibrahim, Mounir; Danila, Daniel; Simon, Terrence; Mantell, Susan; Sun, Liyong; Gadeon, David; Qiu, Songgang; Wood, Gary; Kelly, Kevin; McLean, Jeffrey

    2007-01-01

    An actual-size microfabricated regenerator comprised of a stack of 42 disks, 19 mm diameter and 0.25 mm thick, with layers of microscopic, segmented, involute-shaped flow channels was fabricated and tested. The geometry resembles layers of uniformly-spaced segmented-parallel-plates, except the plates are curved. Each disk was made from electro-plated nickel using the LiGA process. This regenerator had feature sizes close to those required for an actual Stirling engine but the overall regenerator dimensions were sized for the NASA/Sunpower oscillating-flow regenerator test rig. Testing in the oscillating-flow test rig showed the regenerator performed extremely well, significantly better than currently used random-fiber material, producing the highest figures of merit ever recorded for any regenerator tested in that rig over its approximately 20 years of use.

  12. Simultaneous recording of rat auditory cortex and thalamus via a titanium-based, microfabricated, microelectrode device

    NASA Astrophysics Data System (ADS)

    McCarthy, P. T.; Rao, M. P.; Otto, K. J.

    2011-08-01

    Direct recording from sequential processing stations within the brain has provided opportunity for enhancing understanding of important neural circuits, such as the corticothalamic loops underlying auditory, visual, and somatosensory processing. However, the common reliance upon microwire-based electrodes to perform such recordings often necessitates complex surgeries and increases trauma to neural tissues. This paper reports the development of titanium-based, microfabricated, microelectrode devices designed to address these limitations by allowing acute recording from the thalamic nuclei and associated cortical sites simultaneously in a minimally invasive manner. In particular, devices were designed to simultaneously probe rat auditory cortex and auditory thalamus, with the intent of recording auditory response latencies and isolated action potentials within the separate anatomical sites. Details regarding the design, fabrication, and characterization of these devices are presented, as are preliminary results from acute in vivo recording.

  13. A System for Trapping Barium Ions in a Microfabricated Surface Trap

    NASA Astrophysics Data System (ADS)

    Zhou, Zichao; Wright, John; Graham, Richard; Sakrejda, Tomasz; Chen, Bing; Blinov, Boris; Musiqc Team

    2013-05-01

    We have developed a vacuum chamber and control system for rapid testing and development of microfabricated surface traps. Barium ions have been successfully cooled and trapped in this system. The dark lifetime of a single 138Ba + in this trap is up to 30s. And we can shuttle of ions at rate of 8 cm/s between different potential zones. Our system uses a modular design and is based on an in-vacuum PCB with integrated filters. Control of up to 96 DC electrodes is achieved with an update rate of 20 kHz using a custom FPGA based control system. Collection of fluorescence light over a numerical aperture of 0.28 has been achieved. This work is supported by IAPRA.

  14. Optimization design for selective extraction of size-fractioned DNA sample in microfabricated electrophoresis devices

    NASA Astrophysics Data System (ADS)

    Lin, Rongsheng; Burke, David T.; Burns, Mark A.

    2004-03-01

    In recent years, there has been tremendous interest in developing a highly integrated DNA analysis system using microfabrication techniques. With the success of incorporating sample injection, reaction, separation and detection onto a monolithic silicon device, addition of otherwise time-consuming components in macroworld such as sample preparation is gaining more and more attention. In this paper, we designed and fabricated a miniaturized device, capable of separating size-fractioned DNA sample and extracting the band of interest. In order to obtain pure target band, a novel technique utilizing shaping electric field is demonstrated. Both theoretical analysis and experimental data shows significant agreement in designing appropriate electrode structures to achieve the desired electric field distribution. This technique has a very simple fabrication procedure and can be readily added with other existing components to realize a highly integrated "lab-on-a-chip" system for DNA analysis.

  15. Microfabricated DNA analysis system. Semi-annual report, August 1993--January 1994

    SciTech Connect

    Northrup, M.A.

    1994-01-01

    We are miniaturizing instrumentation for the polymerase chain reaction (PCR) -- a bioanalytical technique that amplifies target sections of DNA through thermal cycling. This report focuses on delineating reaction chamber, design parameters through computer modeling and infrared imaging. We have also continued micro-chamber-based PCR experiments and have successfully amplified three different targets from two different biological sources. Specifically, we have amplified DNA from {beta}-globin (a subunit of hemoglobin), and two different-sized targets from the Human Immunodeficiency Virus (HIV). These experiments were performed in newly-designed chambers. Reaction chambers are also being designed with detection in mind, specifically for the detection of fluorescent DNA labels. Finally, some new developments in PCR technology are described as they represent potential biological diagnostics to be evaluated in microfabricated DNA analysis systems.

  16. Metal-Organic Framework Thin Films as Stationary Phases in Microfabricated Gas-Chromatography Columns.

    SciTech Connect

    Read, Douglas; Sillerud, Colin Halliday

    2016-01-01

    The overarching goal of this project is to integrate Sandia's microfabricated gas-chromatography ( GC) columns with a stationary phase material that is capable of retaining high-volatility chemicals and permanent gases. The successful integration of such a material with GCs would dramatically expand the repertoire of detectable compounds for Sandia's various microanalysis systems. One such promising class of candidate materials is metal-organic frameworks (MOFs). In this report we detail our methods for controlled deposition of HKUST-1 MOF stationary phases within GC columns. We demonstrate: the chromatographic separation of natural gas; a method for determining MOF film thickness from chromatography alone; and the first-reported GC x GC separation of natural gas -- in general -- let alone for two disparate MOF stationary phases. In addition we determine the fundamental thermodynamic constant for mass sorption, the partition coefficient, for HKUST-1 and several light hydrocarbons and select toxic industrial chemicals.

  17. A system for trapping barium ions in a microfabricated surface trap

    SciTech Connect

    Graham, R. D. Sakrejda, T.; Wright, J.; Zhou, Z.; Blinov, B. B.; Chen, S.-P.

    2014-05-15

    We have developed a vacuum chamber and control system for rapid testing of microfabricated surface ion traps. Our system is modular in design and is based on an in-vacuum printed circuit board with integrated filters. We have used this system to successfully trap and cool barium ions and have achieved ion ‘dark' lifetimes of 31.6 s ± 3.4 s with controlled shuttling of ions. We provide a detailed description of the ion trap system including the in-vacuum materials used, control electronics and neutral atom source. We discuss the challenges presented in achieving a system which can work reliably over two years of operations in which the trap under test was changed at least 10 times.

  18. Enhanced sensitivity of a microfabricated resonator using a graphene-polystyrene bilayer membrane

    SciTech Connect

    Yun, Minhyuk; Lee, Eunho; Cho, Kilwon; Jeon, Sangmin

    2014-08-18

    A graphene layer was synthesized using chemical vapor deposition methods and a polystyrene solution was spin-cast onto the graphene film. The graphene-polystyrene bilayer membrane was attached between the two tines of a microfabricated quartz tuning fork (QTF). The modulus of the graphene-polystyrene bilayer was measured to be twice that of a pristine polystyrene membrane. Exposure of the membrane-coated QTF to ethanol vapor decreased the resonance frequency of the microresonator. The bilayer membrane-coated QTF produced a frequency change that was three times the change obtained using a polystyrene membrane-coated QTF, with a lower degree of degradation in the Q factor. The limit of detection of the bilayer membrane-coated QTF to ethanol vapor was determined to be 20 ppm.

  19. Microfabric Vessels for Embryoid Body Formation and Rapid Differentiation of Pluripotent Stem Cells.

    PubMed

    Sato, Hiroki; Idiris, Alimjan; Miwa, Tatsuaki; Kumagai, Hiromichi

    2016-01-01

    Various scalable three-dimensional culture systems for regenerative medicine using human induced pluripotent stem cells (hiPSCs) have been developed to date. However, stable production of hiPSCs with homogeneous qualities still remains a challenge. Here, we describe a novel and simple embryoid body (EB) formation system using unique microfabricated culture vessels. Furthermore, this culture system is useful for high throughput EB formation and rapid generation of differentiated cells such as neural stem cells (NSCs) from hiPSCs. The period of NSC differentiation was significantly shortened under high EB density culture conditions. Simultaneous mass production of a pure population of NSCs was possible within 4 days. These results indicate that the novel culture system might not only become a unique tool to obtain new insights into developmental biology based on human stem cells, but also provide an important tractable platform for efficient and stable production of NSCs for clinical applications. PMID:27507707

  20. Near-field fluorescence imaging with 32 nm resolution based on microfabricated cantilevered probes

    NASA Astrophysics Data System (ADS)

    Eckert, Rolf; Freyland, J. Moritz; Gersen, Henkjan; Heinzelmann, Harry; Schürmann, Gregor; Noell, Wilfried; Staufer, Urs; de Rooij, Nico F.

    2000-12-01

    High-resolution near-field optical imaging with microfabricated probes is demonstrated. The probes are made from solid quartz tips fabricated at the end of silicon cantilevers and covered with a 60-nm-thick aluminum film. Transmission electron micrographs indicate a continuous aluminum layer at the tip apex. A specially designed instrument combines the advantages of near-field optical and beam-deflection force microscopy. Near-field optical data of latex bead projection patterns in transmission and of single fluorophores have been obtained in constant-height imaging mode. An artifact-free optical resolution of 31.7±3.6 nm has been deduced from full width at half maximum values of single molecule images.

  1. A microfabricated deformability-based flow cytometer with application to malaria

    PubMed Central

    Bow, Hansen; Pivkin, Igor; Diez-Silva, Monica; Goldfless, Stephen J.; Dao, Ming; Niles, Jacquin C.; Suresh, Subra; Han, Jongyoon

    2012-01-01

    Malaria resulting from Plasmodium falciparum infection is a major cause of human suffering and mortality. Red blood cell (RBC) deformability plays a major role in the pathogenesis of malaria. Here we introduce an automated microfabricated “deformability cytometer” that measures dynamic mechanical responses of 103–104 individual RBCs in a cell population. Fluorescence measurements of each RBC are simultaneously acquired, resulting in a population-based correlation between biochemical properties, such as cell surface markers and dynamic mechanical deformability. This device is especially applicable to heterogeneous cell populations. We demonstrate its ability to mechanically characterize a small number of P. falciparum-infected (ring stage) RBCs in a large population of uninfected RBCs. Furthermore, we are able to infer quantitative mechanical properties of individual RBCs from the observed dynamic behavior through a dissipative particle dynamics (DPD) model. These methods collectively provide a systematic approach to characterize the biomechanical properties of cells in a high-throughput manner. PMID:21293801

  2. Rapid microfabrication of transparent materials using a filamented beam of the IR femtosecond laser

    NASA Astrophysics Data System (ADS)

    Butkus, S.; Paipulas, D.; Viburys, Ž.; Alesenkov, A.; Gaižauskas, E.; KaškelytÄ--, D.; Barkauskas, M.; Sirutkaitis, V.

    2014-03-01

    Glass drilling and welding applications realized with the help of femtosecond lasers attract industrial attention , however, desired tasks may require systems employing high numerical aperture (NA) focusing conditions, low repetition rate lasers and complex fast motion translation stages. Due to the sensitivity of such systems, slight instabilities in parameter values can lead to crack formations, severe fabrication rate decrement and poor quality overall results. A microfabrication system lacking the stated disadvantages was constructed and demonstrated in this report. An f-theta lens was used in combination with a galvanometric scanner, in addition, a water pumping system that enables formation of water films of variable thickness in real time on the samples. Water acts as a medium for filament formation, which in turn decreases the focal spot diameter and increases fluence and axial focal length . This article demonstrates the application of a femtosecond (280fs) laser towards two different micromachining techniques: rapid cutting and welding of transparent materials. Filament formation in water gives rise to strong ablation at the surface of the sample, moreover, the water, surrounding the ablated area, adds increased cooling and protection from cracking. The constructed microfabrication system is capable of drilling holes in thick soda-lime and hardened glasses. The fabrication time varies depending on the diameter of the hole and spans from a few to several hundred seconds. Moreover, complex-shape fabrication was demonstrated. Filament formation at the interface of two glass samples was also used for welding applications. By varying repetition rate, scanning speed and focal position optimal conditions for strong glass welding via filamentation were determined.

  3. Toward a microfabricated preconcentrator-focuser for a wearable micro-scale gas chromatograph.

    PubMed

    Bryant-Genevier, Jonathan; Zellers, Edward T

    2015-11-27

    This article describes work leading to a microfabricated preconcentrator-focuser (μPCF) designed for integration into a wearable microfabricated gas chromatograph (μGC) for monitoring workplace exposures to volatile organic compounds (VOCs) ranging in vapor pressure from ∼0.03 to 13kPa at concentrations near their respective Threshold Limit Values. Testing was performed on both single- and dual-cavity, etched-Si μPCF devices with Pyrex caps and integrated resistive heaters, packed with the graphitized carbons Carbopack X (C-X) and/or Carbopack B (C-B). Performance was assessed by measuring the 10% breakthrough volumes and injection bandwidths of a series of VOCs, individually and in mixtures, as a function of the VOC air concentrations, mixture complexity, sampling and desorption flow rates, adsorbent masses, temperature, and the injection split ratio. A dual-cavity device containing 1.4mg of C-X and 2.0mg of C-B was capable of selectively and quantitatively capturing a mixture of 14 VOCs at low-ppm concentrations in a few minutes from sample volumes sufficiently large to permit detection at relevant concentrations for workplace applications with the μGC detector that we ultimately plan to use. Thermal desorption at 225°C for 40s yielded ≥99% desorption of all analytes, and injected bandwidths as narrow as 0.6s facilitated efficient separation on a downstream 6-m GC column in <3min. A preconcentration factor of 620 was achieved for benzene from a sample of just 31mL. Increasing the mass of C-X to 2.3mg would be required for exhaustive capture of the more volatile target VOCs at high-ppm concentrations. PMID:26530144

  4. Meso- and microfabric analysis of eastern Blue Ridge rocks at Glade Gap, North Carolina

    SciTech Connect

    Geddes, D.J.; Green, M.D. . Dept. of Geological Sciences); Hatcher, R.D. Jr. . Dept. of Geological Sciences Oak Ridge National Lab., TN )

    1993-03-01

    Glade Gap is located in the hanging wall of the Chunky Gal Mountain (Shope Fork ) thrust sheet, a higher tectonic unit in the Hayesville sheet in the eastern Blue Ridge, about 5 km east of Shooting Creek, North Carolina. The rocks here are complexly deformed and were metamorphosed to upper amplibolite facies (sillimanite II) assemblages during the early to middle Paleozoic thermal peak. Evidence for only one high-grade metamorphic event is present here, although minor chlorite (after biotite) and sericite (after feldspar) are present indicating some late retrogression has occurred. Protoliths consisted of mafic igneous rocks (part of the Buck Creek [Chunky Gal] complex), pelite, impute sandstone, and banded iron formation ( -now garnet-quartz coticule ). Three episodes of deformation have been recognized. D[sub 1] consists of an early foliation and intrafolial folds preserved in boudins and porphyroclasts. These structures were transposed by D[sub 2] that produced the dominant foliation, along with early isoclinal flexural- and passive flow folds (EW to NE trend, axial surfaces dip gently to moderately NW and SE, vergence is N to NW). Crystal-plastic deformation mechanisms dominate the microfabric during all early deformational events; strained (unannealed) quartz is present in some sections indicating a late-stage (Alleghanian ) deformational overprint. D[sub 3] consists of crenulations and tight to open folds (NE trend, axial surfaces dip moderately to steeply SE, interlimb angles are 50 to 70[degree], NW vergence). The degree of recrystallization of the microfabrics indicates D[sub 3] may have occurred during the warning stages of the thermal event. The structures preserved in this assemblage were formed during the emplacement of the major structures in this part of the Blue Ridge, and are representative of structures and deformational processes recognized elsewhere in the internal parts of the southern Appalachian Blue Ridge.

  5. Microfabrication of a two-stage BioMEMS microfluidic cell sorter

    NASA Astrophysics Data System (ADS)

    Grafton, Meggie M.; Geheb, Benjamin; Jang, Jae Hyuk; Chuang, Han-Sheng; Rajdev, Pooja; Reece, Lisa M.; Irazoqui, Pedro P.; Wereley, Steven T.; Jung, Byunghoo; Leary, James F.

    2009-02-01

    Point-of-care devices represent the future for medical technologies. Current diagnostic tools are cumbersome, expensive, complicated, and often at risk for contamination. There is a need for cost effective, portable, closed-system, high-speed cell screening and cell isolating device. A microfabricated, exponentially-staging, BioMEMS microfluidic cytometer/cell sorting device offers these advantages over current technologies. A two-stage branched architecture allows the study of inter-particle spacing, flow relations, pressure measurements, and cell behavior in an environment where fluorescence detection is used to identify and analyze certain cellular characteristics. This device was microfabricated using the polymer PDMS to transmit light effectively, to be inexpensive and disposable, and to be easy to manipulate. For initial prototyping, an inverted fluorescent Nikon microscope provided the necessary excitation to view the particles and cells. For the portable device, avalanche photo diodes (APDs) and light emitting diodes (LEDs) are being incorporated into the device for the detection and excitation respectively. For low light level applications, sigma-delta modulation methods are being applied to reduce noise susceptibility and to detect the APD signal more efficiently. In addition, a data acquisition system (DAQ) has been designed that can effectively track signals from a cell sorter using a digital signal processing (DSP) board and a laptop computer. Currently elastomeric valves for diverting flow have been incorporated into the microfluidic chip. Measurements are being made of the effects of the microfluidics valve structures, or the simple opening and closing of selected channels to divert flow and cells down specific channels depending on their measured properties.

  6. Microfabrication of diamond-based slow-wave circuits for mm-wave and THz vacuum electronic sources

    NASA Astrophysics Data System (ADS)

    Lueck, M. R.; Malta, D. M.; Gilchrist, K. H.; Kory, C. L.; Mearini, G. T.; Dayton, J. A.

    2011-06-01

    Planar and helical slow-wave circuits for THz radiation sources have been made using novel microfabrication and assembly methods. A biplanar slow-wave circuit for a 650 GHz backward wave oscillator (BWO) was fabricated through the growth of diamond into high aspect ratio silicon molds and the selective metallization of the tops and sidewalls of 90 µm tall diamond features using lithographically created shadow masks. Helical slow-wave circuits for a 650 GHz BWO and a 95 GHz traveling wave tube were created through the patterning of trenches in thin film diamond, electroplating of gold half-helices, and high accuracy bonding of helix halves. The development of new techniques for the microfabrication of vacuum electronic components will help to facilitate compact and high-power sources for terahertz range radiation.

  7. Microfabrication of a Segmented-Involute-Foil Regenerator, Testing in a Sunpower Stirling Convertor and Supporting Modeling and Analysis

    NASA Technical Reports Server (NTRS)

    Ibrahim, Mounir B.; Tew, Roy C.; Gedeon, David; Wood, Gary; McLean, Jeff

    2008-01-01

    Under Phase II of a NASA Research Award contract, a prototype nickel segmented-involute-foil regenerator was microfabricated via LiGA and tested in the NASA/Sunpower oscillating-flow test rig. The resulting figure-of-merit was about twice that of the approx.90% porosity random-fiber material currently used in the small 50-100 W Stirling engines recently manufactured for NASA. That work was reported at the 2007 International Energy Conversion Engineering Conference in St. Louis, was also published as a NASA report, NASA/TM-2007-2149731, and has been more completely described in a recent NASA Contractor Report, NASA/CR-2007-2150062. Under a scaled-back version of the original Phase III plan, a new nickel segmentedinvolute- foil regenerator was microfabricated and has been tested in a Sunpower Frequency-Test-Bed (FTB) Stirling convertor. Testing in the FTB convertor produced about the same efficiency as testing with the original random-fiber regenerator. But the high thermal conductivity of the prototype nickel regenerator was responsible for a significant performance degradation. An efficiency improvement (by a 1.04 factor, according to computer predictions) could have been achieved if the regenerator been made from a low-conductivity material. Also the FTB convertor was not reoptimized to take full advantage of the microfabricated regenerator's low flow resistance; thus the efficiency would likely have been even higher had the FTB been completely reoptimized. This report discusses the regenerator microfabrication process, testing of the regenerator in the Stirling FTB convertor, and the supporting analysis. Results of the pre-test computational fluid dynamics (CFD) modeling of the effects of the regenerator-test-configuration diffusers (located at each end of the regenerator) is included. The report also includes recommendations for accomplishing further development of involute-foil regenerators from a higher-temperature material than nickel.

  8. Influence of Protolith Composition and Sliding Velocity on the Microfabric of Fault Gouge: Experimental Results

    NASA Astrophysics Data System (ADS)

    Song, C.; Underwood, M.; Schleicher, A.; Ikari, M.; Saffer, D. M.; Marone, C.

    2013-12-01

    The relation between fault gouge fabric and fault-slip behavior remains a central unknown in our knowledge of fault and earthquake mechanics. The linkage of cause to effect remains cryptic in part because natural gouges are highly variable (i.e., particle size distribution, mineralogy, microfabric), due to the heterogeneity of protoliths and differences in cumulative slip. To help isolate key variables, we conducted a series of direct shearing tests in a double direct shear configuration, on specimens of artificial powdered gouge. The experiments were conducted under room temperature and humidity conditions (RH = 14.4-32.8%), using ~3 mm-thick (prior to shearing) layers with nominal contact areas of 5x5 cm. Layers were sheared between grooved steel forcing blocks designed to minimize slip at the layer boundary. We tested four gouge compositions: illitic shale, chlorite schist, a 50:50 mixture of smectite and quartz, and Westerly granite. Three load point sliding velocities were applied (1.15, 11.5, and 115 microns/sec), and all experiments were conducted under a normal stress of ~50 MPa. As expected, the coefficients of friction vary as a function of both composition and sliding velocity. The smectite:quartz mixture is consistently weakest (0.38-0.39) and granite gouge is consistently strongest (0.60-0.61). Gouges of illitic shale and chlorite schist yielded larger differences as a function of sliding velocity, 0.40-0.53 and 0.48-0.58, respectively. To characterize the microfabric that developed within each sample during shearing, the twelve experimental wafers were analyzed by X-ray texture goniometry (XTG) and imaged (uncoated) using an FEI Quanta 600 scanning electron microscopy in low vacuum mode (80 Pa). SEM images were shot parallel and perpendicular to the shear plane at high voltage (30 kV) with spot size of 3.0 and working distance of 10 mm. After processing the digital images (1000X magnification), we ran statistical analyses of the apparent long

  9. Quartz microfabrics in ultrahigh-pressure metamorphic rocks as indicators of low stress during uplift

    NASA Astrophysics Data System (ADS)

    Stäb, C.; Kruhl, J. H.; Trepmann, C.; Wang, L.

    2012-12-01

    Ultrahigh-pressure (UHP) metamorphic rocks form in convergent tectonic settings at depths > 90 km. In general, UHP conditions are defined by the stability of coesite. Coesite inclusions in various host minerals are a common feature in UHP rocks. We present data of typical quartz microfabrics, which resulted from the transformation of coesite to quartz in inclusions and intergranular regions, and evidence of high temperature quartz microfabrics. Jadeite-quartzites and eclogites from the Dabie Shan - Sulu orogenic belt (central China) were investigated, both of which experienced peak UHP conditions of ~ 660°C / > 2.6 GPa (Liou et al., 1997) and 700-800°C / 3.1-4.1 GPa (Yoshida et al., 2004), respectively, at c. 220-230 Ma due to a N-subduction of the Yangtze craton beneath the Sino-Korean craton, followed by a nearly isothermal decompression to ~ 1 GPa. Both rocks contain coesite and/or quartz inclusions (up to 350 μm in diameter) in clinopyroxene and garnet and in their symplectitic rims with various microstructures: (i) rims of palisade quartz commonly in contact to coesite, (ii) quartz aggregates with sutured grain boundaries and central remnants of coesite, (iii) larger central quartz grains with subgrains, (iv) foam quartz (c. 50 μm sized), and (v) apparently strain-free single quartz crystals. The foam quartz shows a random c-axis distribution but preferred crystallographic orientations of grain boundaries. Intergranular foam quartz is found in quartz-eclogites from the Sulu region, most probably indicating quartz-coesite transformation and, therefore, former UHP conditions. The preservation of foam quartz in intergranular regions and inclusions (especially in symplectites) indicates low stress and nearly no deformation during uplift in the stability field of quartz. This points to strain localization in shear zones (Zhao et al., 2003). In veins in the jadeite-quartzites and quartz-eclogites quartz occurs in larger aggregates with sutured grain boundaries

  10. Microfabrication and integration of a sol-gel PZT folded spring energy harvester.

    PubMed

    Lueke, Jonathan; Badr, Ahmed; Lou, Edmond; Moussa, Walied A

    2015-01-01

    This paper presents the methodology and challenges experienced in the microfabrication, packaging, and integration of a fixed-fixed folded spring piezoelectric energy harvester. A variety of challenges were overcome in the fabrication of the energy harvesters, such as the diagnosis and rectification of sol-gel PZT film quality and adhesion issues. A packaging and integration methodology was developed to allow for the characterizing the harvesters under a base vibration. The conditioning circuitry developed allowed for a complete energy harvesting system, consisting a harvester, a voltage doubler, a voltage regulator and a NiMH battery. A feasibility study was undertaken with the designed conditioning circuitry to determine the effect of the input parameters on the overall performance of the circuit. It was found that the maximum efficiency does not correlate to the maximum charging current supplied to the battery. The efficiency and charging current must be balanced to achieve a high output and a reasonable output current. The development of the complete energy harvesting system allows for the direct integration of the energy harvesting technology into existing power management schemes for wireless sensing. PMID:26016911

  11. DESIGN OF A MICROFABRICATED, TWO-ELECTRODE PHASE-CONTRAST ELEMENTSUITABLE FOR ELECTRON MICROSCOPY

    SciTech Connect

    Cambie, Rossana; Downing, Kenneth H.; Typke, Dieter; Glaeser,Robert M.; Jin, Jian

    2006-09-20

    A miniature electrostatic element has been designed to selectively apply a ninety-degree phase shift to the unscattered beam in the back focal plane of the objective lens, in order to realize Zernike-type, in-focus phase contrast in an electron microscope. The design involves a cylindrically shaped, biased-voltage electrode, which is surrounded by a concentric grounded electrode. Electrostatic calculations have been used to determine that the fringing fields in the region of the scattered electron beams will cause a negligible phase shift as long as the ratio of electrode length to the transverse feature-size is greater than 5:1. Unlike the planar, three-electrode einzel lens originally proposed by Boersch for the same purpose, this new design does not require insulating layers to separate the biased and grounded electrodes, and it can thus be produced by a very simple microfabrication process. Scanning electron microscope images confirm that mechanically robust devices with feature sizes of {approx}1 {micro}m can be easily fabricated. Preliminary experimental images demonstrate that these devices do apply a 90-degree phase shift between the scattered and unscattered electrons, as expected.

  12. Preferred orientation of phyllosilicates: Effects of composition and stress on resedimented mudstone microfabrics

    NASA Astrophysics Data System (ADS)

    Day-Stirrat, Ruarri J.; Schleicher, Anja M.; Schneider, Julia; Flemings, Peter B.; Germaine, John T.; van der Pluijm, Ben A.

    2011-09-01

    Development of a preferred orientation of clay minerals is investigated in response to changes in vertical effective stress and composition in resedimented material (Boston Blue Clay). Boston Blue Clay (BBC), an illitic glacio-marine clay composed of 57% clay-sized particles (<2 μm) was resedimented and step-loaded to a vertical effective stress of 0.1 MPa, 1 MPa, 6 MPa, and 10 MPa. These four samples show a small increase in preferred orientation of mica and chlorite with increasing vertical effective stress. Furthermore, pure BBC powder was admixed with silica (silt-sized quartz) in five different ratios of BBC:silica to form sediments with 57%, 52%, 48%, 44%, and 36% < 2 μm particles and were loaded to a maximum vertical effective stress of 2.4 MPa. Mica preferred orientation decreases significantly with decreasing clay content at one stress state. We used and compared three different techniques to characterize and quantify the preferred orientation of phyllosilicates: transmission-mode X-ray texture goniometry, reflection-mode X-ray texture goniometry, and grain and pore networks imaged using secondary and backscattered electron micrographs gathered on argon-ion-milled surfaces. Preferred orientation of the clay minerals shows good agreement between transmission-mode X-ray texture goniometry and reflection-mode X-ray texture goniometry. Mercury porosimetry further illuminates vertical effective stress and compositional controls on microfabric.

  13. Polyhalite microfabrics in an Alpine evaporite mélange: Hallstatt, Eastern Alps

    PubMed Central

    Schorn, Anja; Neubauer, Franz; Bernroider, Manfred

    2013-01-01

    In the Hallstatt salt mine (Austria), polyhalite rocks occur in 0.5–1 m thick and several metre long tectonic lenses within the protocataclasite to protomylonite matrix of the Alpine Haselgebirge Fm.. Thin section analysis of Hallstatt polyhalites reveals various fabric types similar to metamorphic rocks of crust-forming minerals, e.g. quartz and feldspar. Polyhalite microfabrics from Hallstatt include: (1) polyhalite mylonites, (2) metamorphic reaction fabrics, (3) vein-filling, fibrous polyhalite and (4) cavity-filling polyhalite. The polyhalite mylonites contain a wide range of shear fabrics commonly known in mylonitic quartzo–feldspathic shear zones within the ductile crust and developed from a more coarse-grained precursor rock. The mylonites are partly overprinted by recrystallised, statically grown polyhalite grains. Metamorphic reaction fabrics of polyhalite fibres between blödite (or astrakhanite) [Na2Mg(SO4)2.4H2O] and anhydrite have also been found. According to previous reports, blödite may occur primarily as nodules or intergrown with löweite. Reaction fabrics may have formed by exsolution, (re-)crystallisation, parallel growth or replacement. This fabric type was only found in one sample in relation with the decomposition of blödite at ca. 61 °C in the presence of halite or slightly above, testifying, therefore, a late stage prograde fabric significantly younger than the main polyhalite formation. PMID:26806997

  14. Effect of microfabricated microgroove-surface devices on the morphology of mesenchymal stem cells.

    PubMed

    Zhang, Xiangkai; Aoyama, Tomoki; Yasuda, Takashi; Oike, Makoto; Ito, Akira; Tajino, Junichi; Nagai, Momoko; Fujioka, Rune; Iijima, Hirotaka; Yamaguchi, Shoki; Kakinuma, Norihiro; Kuroki, Hiroshi

    2015-12-01

    The surface of a material that is in contact with cells is known to affect cell morphology and function. To develop an appropriate surface for tendon engineering, we used zigzag microgroove surfaces, which are similar to the tenocyte microenvironment. The purpose of this study was to investigate the effect of microgroove surfaces with different ridge angles (RAs), ridge lengths (RLs), ridge widths (RWs), and groove widths (GWs) on human bone marrow-derived mesenchymal stem cell (MSC) shape. Dishes with microgroove surfaces were fabricated using cyclic olefin polymer by injection-compression molding. The other parameters were fixed, and effects of different RAs (180 - 30 °), RLs (5 - 500 μm), RWs (5 - 500 μm), and GWs (5 - 500 μm) were examined. Changes in the zigzag shape of the cell due to different RAs, RLs, RWs, and GWs were observed by optical microscopy and scanning electron microscopy. Cytoskeletal changes were investigated using Phalloidin immunofluorescence staining. As observed by optical microscopy, MSCs changed to a zigzag shape in response to microgroove surfaces with different ridge and groove properties. . As observed by scanning electron microscopy, the cell shape changed at turns in the microgroove surface. Phalloidin immunofluorescence staining indicated that F-actin, not only in cell filopodia but also inside the cell body, changed orientation to conform to the microgrooves. In conclusion, the use of zigzag microgroove surfaces microfabricated by injection-compression molding demonstrated the property of MSCs to alter their shapes to fit the surface. PMID:26573821

  15. Microfabricated FSCV-Compatible Microelectrode Array for Real-time Monitoring of Heterogeneous Dopamine Release

    PubMed Central

    Zachek, Matthew K.; Park, Jinwoo; Takmakov, Pavel; Wightman, R. Mark; McCarty, Gregory S.

    2010-01-01

    Fast scan cyclic voltammetry (FSCV) has been used previously to detect neurotransmitter release and reuptake in vivo. An advantage that FSCV has over other electrochemical techniques is its ability to distinguish neurotransmitters of interest (i.e. monoamines) from their metabolites using their respective characteristic cyclic voltammogram. While much has been learned with this technique, it has generally only been used in a single working electrode arrangement. Additionally, traditional electrode fabrication techniques tend to be difficult and somewhat irreproducible. Described in this report is a fabrication method for a FSCV compatible microelectrode array (FSCV-MEA) that is capable of functioning in vivo. The microfabrication techniques employed here allow for better reproducibility than traditional fabrication methods of carbon fiber microelectrodes, and enable batch fabrication of electrode arrays. The reproducibility and electrochemical qualities of the probes were assessed along with cross talk in vitro. Heterogeneous release of electrically stimulated dopamine was observed in real-time in the striatum of an anesthetized rat using the FSCV-MEA. The heterogeneous effects of pharmacology on the striatum was also observed and shown to be consistent across multiple animals. PMID:20464031

  16. Scalable Microfabrication Procedures for Adhesive-Integrated Flexible and Stretchable Electronic Sensors

    PubMed Central

    Kang, Dae Y.; Kim, Yun-Soung; Ornelas, Gladys; Sinha, Mridu; Naidu, Keerthiga; Coleman, Todd P.

    2015-01-01

    New classes of ultrathin flexible and stretchable devices have changed the way modern electronics are designed to interact with their target systems. Though more and more novel technologies surface and steer the way we think about future electronics, there exists an unmet need in regards to optimizing the fabrication procedures for these devices so that large-scale industrial translation is realistic. This article presents an unconventional approach for facile microfabrication and processing of adhesive-peeled (AP) flexible sensors. By assembling AP sensors on a weakly-adhering substrate in an inverted fashion, we demonstrate a procedure with 50% reduced end-to-end processing time that achieves greater levels of fabrication yield. The methodology is used to demonstrate the fabrication of electrical and mechanical flexible and stretchable AP sensors that are peeled-off their carrier substrates by consumer adhesives. In using this approach, we outline the manner by which adhesion is maintained and buckling is reduced for gold film processing on polydimethylsiloxane substrates. In addition, we demonstrate the compatibility of our methodology with large-scale post-processing using a roll-to-roll approach. PMID:26389915

  17. Microfabrication of complex porous tissue engineering scaffolds using 3D projection stereolithography

    PubMed Central

    Gauvin, Robert; Chen, Ying-Chieh; Lee, Jin Woo; Soman, Pranav; Zorlutuna, Pinar; Nichol, Jason W.; Bae, Hojae; Chen, Shaochen; Khademhosseini, Ali

    2013-01-01

    The success of tissue engineering will rely on the ability to generate complex, cell seeded three-dimensional (3D) structures. Therefore, methods that can be used to precisely engineer the architecture and topography of scaffolding materials will represent a critical aspect of functional tissue engineering. Previous approaches for 3D scaffold fabrication based on top-down and process driven methods are often not adequate to produce complex structures due to the lack of control on scaffold architecture, porosity, and cellular interactions. The proposed projection stereolithography (PSL) platform can be used to design intricate 3D tissue scaffolds that can be engineered to mimic the microarchitecture of tissues, based on computer aided design (CAD). The PSL system was developed, programmed and optimized to fabricate 3D scaffolds using gelatin methacrylate (GelMA). Variation of the structure and prepolymer concentration enabled tailoring the mechanical properties of the scaffolds. A dynamic cell seeding method was utilized to improve the coverage of the scaffold throughout its thickness. The results demonstrated that the interconnectivity of pores allowed for uniform human umbilical vein endothelial cells (HUVECs) distribution and proliferation in the scaffolds, leading to high cell density and confluency at the end of the culture period. Moreover, immunohistochemistry results showed that cells seeded on the scaffold maintained their endothelial phenotype, demonstrating the biological functionality of the microfabricated GelMA scaffolds. PMID:22365811

  18. Microfabrication of complex porous tissue engineering scaffolds using 3D projection stereolithography.

    PubMed

    Gauvin, Robert; Chen, Ying-Chieh; Lee, Jin Woo; Soman, Pranav; Zorlutuna, Pinar; Nichol, Jason W; Bae, Hojae; Chen, Shaochen; Khademhosseini, Ali

    2012-05-01

    The success of tissue engineering will rely on the ability to generate complex, cell seeded three-dimensional (3D) structures. Therefore, methods that can be used to precisely engineer the architecture and topography of scaffolding materials will represent a critical aspect of functional tissue engineering. Previous approaches for 3D scaffold fabrication based on top-down and process driven methods are often not adequate to produce complex structures due to the lack of control on scaffold architecture, porosity, and cellular interactions. The proposed projection stereolithography (PSL) platform can be used to design intricate 3D tissue scaffolds that can be engineered to mimic the microarchitecture of tissues, based on computer aided design (CAD). The PSL system was developed, programmed and optimized to fabricate 3D scaffolds using gelatin methacrylate (GelMA). Variation of the structure and prepolymer concentration enabled tailoring the mechanical properties of the scaffolds. A dynamic cell seeding method was utilized to improve the coverage of the scaffold throughout its thickness. The results demonstrated that the interconnectivity of pores allowed for uniform human umbilical vein endothelial cells (HUVECs) distribution and proliferation in the scaffolds, leading to high cell density and confluency at the end of the culture period. Moreover, immunohistochemistry results showed that cells seeded on the scaffold maintained their endothelial phenotype, demonstrating the biological functionality of the microfabricated GelMA scaffolds. PMID:22365811

  19. Microfabrication Technology for Large Lekid Arrays: From Nika2 to Future Applications

    NASA Astrophysics Data System (ADS)

    Goupy, J.; Adane, A.; Benoit, A.; Bourrion, O.; Calvo, M.; Catalano, A.; Coiffard, G.; Hoarau, C.; Leclercq, S.; Le Sueur, H.; Macias-Perez, J.; Monfardini, A.; Peck, I.; Schuster, K.

    2016-02-01

    The lumped element kinetic inductance detectors (LEKID) demonstrated full maturity in the New IRAM KID Arrays (NIKA) instrument. These results allow directly comparing LEKID performance with other competing technologies (TES, doped silicon) in the mm and sub-mm range. A continuing effort is ongoing to improve the microfabrication technologies and concepts in order to satisfy the requirements of new instruments. More precisely, future satellites dedicated to cosmic microwave background (CMB) studies will require the same focal plane technology to cover, at least, the frequency range of 60-600 GHz. Aluminium LEKID developed for NIKA have so far demonstrated, under real telescope conditions, a performance approaching photon noise limitation in the band 120-300 GHz. By implementing superconducting bi-layers, we recently demonstrated LEKID arrays working in the range 80-120 GHz and with sensitivities approaching the goals for CMB missions. NIKA itself (350 pixels) is followed by a more ambitious project requiring several thousand (3000-5000) pixels. NIKA2 has been installed in October 2015 at the IRAM 30-m telescope. We will describe in detail the technological improvements that allowed a relatively harmless tenfold up-scaling in pixels count without degrading the initial sensitivity. In particular, we will briefly describe a solution to simplify the difficult fabrication step linked to the slot-line propagation mode in coplanar waveguide.

  20. Microfabrication and Integration of a Sol-Gel PZT Folded Spring Energy Harvester

    PubMed Central

    Lueke, Jonathan; Badr, Ahmed; Lou, Edmond; Moussa, Walied A.

    2015-01-01

    This paper presents the methodology and challenges experienced in the microfabrication, packaging, and integration of a fixed-fixed folded spring piezoelectric energy harvester. A variety of challenges were overcome in the fabrication of the energy harvesters, such as the diagnosis and rectification of sol-gel PZT film quality and adhesion issues. A packaging and integration methodology was developed to allow for the characterizing the harvesters under a base vibration. The conditioning circuitry developed allowed for a complete energy harvesting system, consisting a harvester, a voltage doubler, a voltage regulator and a NiMH battery. A feasibility study was undertaken with the designed conditioning circuitry to determine the effect of the input parameters on the overall performance of the circuit. It was found that the maximum efficiency does not correlate to the maximum charging current supplied to the battery. The efficiency and charging current must be balanced to achieve a high output and a reasonable output current. The development of the complete energy harvesting system allows for the direct integration of the energy harvesting technology into existing power management schemes for wireless sensing. PMID:26016911

  1. Exploiting the Oxygen Inhibitory Effect on UV Curing in Microfabrication: A Modified Lithography Technique

    PubMed Central

    Alvankarian, Jafar; Majlis, Burhanuddin Yeop

    2015-01-01

    Rapid prototyping (RP) of microfluidic channels in liquid photopolymers using standard lithography (SL) involves multiple deposition steps and curing by ultraviolet (UV) light for the construction of a microstructure layer. In this work, the conflicting effect of oxygen diffusion and UV curing of liquid polyurethane methacrylate (PUMA) is investigated in microfabrication and utilized to reduce the deposition steps and to obtain a monolithic product. The conventional fabrication process is altered to control for the best use of the oxygen presence in polymerization. A novel and modified lithography technique is introduced in which a single step of PUMA coating and two steps of UV exposure are used to create a microchannel. The first exposure is maskless and incorporates oxygen diffusion into PUMA for inhibition of the polymerization of a thin layer from the top surface while the UV rays penetrate the photopolymer. The second exposure is for transferring the patterns of the microfluidic channels from the contact photomask onto the uncured material. The UV curing of PUMA as the main substrate in the presence of oxygen is characterized analytically and experimentally. A few typical elastomeric microstructures are manufactured. It is demonstrated that the obtained heights of the fabricated structures in PUMA are associated with the oxygen concentration and the UV dose. The proposed technique is promising for the RP of molds and microfluidic channels in terms of shorter processing time, fewer fabrication steps and creation of microstructure layers with higher integrity. PMID:25747514

  2. Development and application of a microfabricated multimodal neural catheter for neuroscience.

    PubMed

    Li, Chunyan; Wu, Zhizhen; Limnuson, Kanokwan; Cheyuo, Cletus; Wang, Ping; Ahn, Chong H; Narayan, Raj K; Hartings, Jed A

    2016-02-01

    We present a microfabricated neural catheter for real-time continuous monitoring of multiple physiological, biochemical and electrophysiological variables that are critical to the diagnosis and treatment of evolving brain injury. The first generation neural catheter was realized by polyimide-based micromachining and a spiral rolling packaging method. The mechanical design and electrical operation of the microsensors were optimized and tailored for multimodal monitoring in rat brain such that the potential thermal, chemical and electrical crosstalk among the microsensors as well as errors from micro-environmental fluctuations are minimized. In vitro cytotoxicity analyses suggest that the developed neural catheters are minimally toxic to rat cortical neuronal cultures. In addition, in vivo histopathology results showed neither acute nor chronic inflammation for 7 days post implantation. The performance of the neural catheter was assessed in an in vivo needle prick model as a translational replica of a "mini" traumatic brain injury. It successfully monitored the expected transient brain oxygen, temperature, regional cerebral blood flow, and DC potential changes during the passage of spreading depolarization waves. We envisage that the developed multimodal neural catheter can be used to decipher the causes and consequences of secondary brain injury processes with high spatial and temporal resolution while reducing the potential for iatrogenic injury inherent to current use of multiple invasive probes. PMID:26780443

  3. A Microfabricated 8-40 GHz Dual-Polarized Reflector Feed

    NASA Technical Reports Server (NTRS)

    Vanhille, Kenneth; Durham, Tim; Stacy, William; Karasiewicz, David; Caba, Aaron; Trent, Christopher; Lambert, Kevin; Miranda, Felix

    2014-01-01

    Planar antennas based on tightly coupled dipole arrays (also known as a current sheet antenna or CSA) are amenable for use as electronically scanned phased arrays. They are capable of performance nearing a decade of bandwidth. These antennas have been demonstrated in many implementations at frequencies below 18 GHz. This paper describes the implementation using a relatively new multi-layer microfabrication process resulting in a small, 6x6 element, dual-linear polarized array with beamformer that operates from 8 to 40 GHz. The beamformer includes baluns that feed the dual-polarized differential antenna elements and reactive splitter networks that also cover the full frequency range of operation. This antenna array serves as a reflector feed for a multi-band instrument designed to measure snow water equivalent (SWE) from airborne platforms. The instrument has both radar and radiome try capability at multiple frequencies. Scattering-parameter and time-domain measurements have been used to characterize the array feed. Radiation patterns of the antenna have been measured and are compared to simulation. To the best of the authors' knowledge, this work represents the most integrated multi-octave millimeter-wave antenna feed fabricated to date.

  4. Concurrent recordings of bladder afferents from multiple nerves using a microfabricated PDMS microchannel electrode array.

    PubMed

    Delivopoulos, Evangelos; Chew, Daniel J; Minev, Ivan R; Fawcett, James W; Lacour, Stéphanie P

    2012-07-21

    In this paper we present a compliant neural interface designed to record bladder afferent activity. We developed the implant's microfabrication process using multiple layers of silicone rubber and thin metal so that a gold microelectrode array is embedded within four parallel polydimethylsiloxane (PDMS) microchannels (5 mm long, 100 μm wide, 100 μm deep). Electrode impedance at 1 kHz was optimized using a reactive ion etching (RIE) step, which increased the porosity of the electrode surface. The electrodes did not deteriorate after a 3 month immersion in phosphate buffered saline (PBS) at 37 °C. Due to the unique microscopic topography of the metal film on PDMS, the electrodes are extremely compliant and can withstand handling during implantation (twisting and bending) without electrical failure. The device was transplanted acutely to anaesthetized rats, and strands of the dorsal branch of roots L6 and S1 were surgically teased and inserted in three microchannels under saline immersion to allow for simultaneous in vivo recordings in an acute setting. We utilized a tripole electrode configuration to maintain background noise low and improve the signal to noise ratio. The device could distinguish two types of afferent nerve activity related to increasing bladder filling and contraction. To our knowledge, this is the first report of multichannel recordings of bladder afferent activity. PMID:22569953

  5. Exploiting the oxygen inhibitory effect on UV curing in microfabrication: a modified lithography technique.

    PubMed

    Alvankarian, Jafar; Majlis, Burhanuddin Yeop

    2015-01-01

    Rapid prototyping (RP) of microfluidic channels in liquid photopolymers using standard lithography (SL) involves multiple deposition steps and curing by ultraviolet (UV) light for the construction of a microstructure layer. In this work, the conflicting effect of oxygen diffusion and UV curing of liquid polyurethane methacrylate (PUMA) is investigated in microfabrication and utilized to reduce the deposition steps and to obtain a monolithic product. The conventional fabrication process is altered to control for the best use of the oxygen presence in polymerization. A novel and modified lithography technique is introduced in which a single step of PUMA coating and two steps of UV exposure are used to create a microchannel. The first exposure is maskless and incorporates oxygen diffusion into PUMA for inhibition of the polymerization of a thin layer from the top surface while the UV rays penetrate the photopolymer. The second exposure is for transferring the patterns of the microfluidic channels from the contact photomask onto the uncured material. The UV curing of PUMA as the main substrate in the presence of oxygen is characterized analytically and experimentally. A few typical elastomeric microstructures are manufactured. It is demonstrated that the obtained heights of the fabricated structures in PUMA are associated with the oxygen concentration and the UV dose. The proposed technique is promising for the RP of molds and microfluidic channels in terms of shorter processing time, fewer fabrication steps and creation of microstructure layers with higher integrity. PMID:25747514

  6. Structural Reinforcement of Cell-Laden Hydrogels with Microfabricated Three Dimensional Scaffolds

    PubMed Central

    Cha, Chaenyung; Soman, Pranav; Zhu, Wei; Nikkhah, Mehdi; Camci-Unal, Gulden

    2013-01-01

    Hydrogels commonly used in tissue engineering are mechanically soft, thus often display structural weakness. Herein, we introduce a strategy for enhancing the structural integrity and fracture toughness of cell-laden hydrogels by incorporating a three-dimensional (3D) microfabricated scaffold as a structural element. A digital micromirror device projection printing (DMD-PP) system, a rapid prototyping technology which employs a layer-by-layer stereolithographic approach, was utilized to efficiently fabricate 3D scaffolds made from photocrosslinkable poly(ethylene glycol) diacrylate (PEGDA). The scaffold was incorporated into a photocrosslinkable gelatin hydrogel by placing it in a pre-gel solution, and inducing in situ hydrogel formation. The resulting scaffold-reinforced hydrogels demonstrated significant increase in ultimate stress and provided structural support for weak hydrogels. In addition, the scaffold did not affect the rigidity of hydrogels, as it was not involved in the crosslinking reaction to form the hydrogel. Therefore, the presented approach could avoid inadvertent and undesired changes in the hydrogel rigidity which is a known regulator of cellular activities. Furthermore, the biocompatibility of scaffold-reinforced hydrogels was confirmed by evaluating the viability and proliferation of encapsulated fibroblasts. Overall, the strategy of incorporating 3D scaffolds into hydrogels as structural reinforcements presented in this study will be highly useful for enhancing the mechanical toughness of hydrogels for various tissue engineering applications. PMID:24778793

  7. Novel microfabricated device to measure hormone/neurotransmitter release with millisecond temporal resolution

    NASA Astrophysics Data System (ADS)

    Gillis, Kevin D.; Chen, Peng; Xu, Bai; Tokranova, Natalya; Feng, Xiaojun; Castracane, James

    2002-06-01

    We are developing a novel readout for secretion of hormones and neurotransmitter on micro/nanofabricated chips. Traditional biochemical assays of signaling molecules secreted from cells are slow, cumbersome and have at best, a temporal resolution of several seconds. On the other hand, electrochemical measurement of hormone or transmitter secretion can obtain millisecond temporal resolution if the diffusion distance between the release site on the cell and the working electrode is within 1 micron. Carbon fiber microelectrodes can have millisecond time resolution, but can only measure release form a small fraction of the cell surface. We have fabricated arrays of Au electrodes in wells micromachined on the surface of silicon microchips. Each well/microelectrode roughly conforms to the shape of a single cell in order to capture release forma large fraction of the surface area of each cell with minimal diffusional delays. This paper will present details of the microfabrication process flow as well a initial results demonstrating millisecond-resolution measurement of catecholamine secretion form adrenal chromaffin cells. Our goal for this project is to develop enabling technology for massively parallel systems on a chip such as cell-based biosensors to detect neurotoxins and high-throughput assays of drugs that affect neurotransmitter release.

  8. A microfabricated fixed path length silicon sample holder improves background subtraction for cryoSAXS

    PubMed Central

    Hopkins, Jesse B.; Katz, Andrea M.; Meisburger, Steve P.; Warkentin, Matthew A.; Thorne, Robert E.; Pollack, Lois

    2015-01-01

    The application of small-angle X-ray scattering (SAXS) for high-throughput characterization of biological macromolecules in solution is limited by radiation damage. By cryocooling samples, radiation damage and required sample volumes can be reduced by orders of magnitude. However, the challenges of reproducibly creating the identically sized vitrified samples necessary for conventional background subtraction limit the widespread adoption of this method. Fixed path length silicon sample holders for cryoSAXS have been microfabricated to address these challenges. They have low background scattering and X-ray absorption, require only 640 nl of sample, and allow reproducible sample cooling. Data collected in the sample holders from a nominal illuminated sample volume of 2.5 nl are reproducible down to q ≃ 0.02 Å−1, agree with previous cryoSAXS work and are of sufficient quality for reconstructions that match measured crystal structures. These sample holders thus allow faster, more routine cryoSAXS data collection. Additional development is required to reduce sample fracturing and improve data quality at low q. PMID:26089749

  9. Microfabricated glow discharge plasma (MFGDP) for ambient desorption/ionization mass spectrometry.

    PubMed

    Ding, Xuelu; Zhan, Xuefang; Yuan, Xin; Zhao, Zhongjun; Duan, Yixiang

    2013-10-01

    A novel ambient ionization technique for mass spectrometry, microfabricated glow discharge plasma (MFGDP), is reported. This device is made of a millimeter-sized ceramic cavity with two platinum electrodes positioned face-to-face. He or Ar plasma can be generated by a direct current voltage of several hundreds of volts requiring a total power below 4 W. The thermal plume temperature of the He plasma was measured and found to be between 25 and 80 °C at a normal discharge current. Gaseous, liquid, creamy, and solid samples with molecular weights up to 1.5 kDa could be examined in both positive and negative mode, giving limits of detection (LOD) at or below the fg/mm(2) level. The relative standard deviation (RSD) of manual sampling ranged from 10% to ~20%, while correlation coefficients of the working curve (R(2)) are all above 0.98 with the addition of internal standards. The ionization mechanisms are examed via both optical and mass spectrometry. Due to the low temperature characteristics of the microplasma, nonthermal momentum desorption is considered to dominate the desorption process. PMID:24000803

  10. Laser microfabrication of biomedical devices: time-resolved microscopy of the printing process

    NASA Astrophysics Data System (ADS)

    Serra, P.; Patrascioiu, A.; Fernández-Pradas, J. M.; Morenza, J. L.

    2013-04-01

    Laser printing constitutes an interesting alternative to more conventional printing techniques in the microfabrication of biomedical devices. The principle of operation of most laser printing techniques relies on the highly localized absorption of strongly focused laser pulses in the close proximity of the free surface of the liquid to be printed. This leads to the generation of a cavitation bubble which further expansion results in the ejection of a small fraction of the liquid, giving place to the deposition of a well-defined droplet onto a collector substrate. Laser printing has proved feasible for printing biological materials, from single-stranded DNA to proteins, and even living cells and microorganisms, with high degrees of resolution and reproducibility. In consequence, laser printing appears to be an excellent candidate for the fabrication of biological microdevices, such as DNA and protein microarrays, or miniaturized biosensors. The optimization of the performances of laser printing techniques requires a detailed knowledge of the dynamics of liquid transfer. Time-resolved microscopy techniques play a crucial role in this concern, since they allow tracking the evolution of the ejected material with excellent time and spatial resolution. Investigations carried out up to date have shown that liquid ejection proceeds through the formation of long, thin and stable liquid jets. In this work the different approaches used so far for monitoring liquid ejection during laser printing are considered, and it is shown how these techniques make possible to understand the complex dynamics involved in the process.

  11. Microfabrication of Arrays of Superconducting Transition Edge Sensors for CMB Measurements

    NASA Astrophysics Data System (ADS)

    Posada, Chrystian; Ding, Junjia; Bender, Amy; Khaire, Trupti; Lendinez, Sergi; Ciocys, Samuel; Wang, Gensheng; Yefremenko, Volodymyr; Padin, Steve; Carlstrom, John; Chang, Clarence; Novosad, Valentine; Spt3G Collaboration

    The cosmic microwave background (CMB) provides a unique window for exploring fundamental physics. Increasing the sensitivity of CMB experiments requires fabricating focal planes with orders of magnitude more detectors than current instruments. This work presents the procedures used at Argonne National Laboratory for the fabrication of large arrays of dual-polarized multichroic detectors for CMB measurements. The detectors are composed of a broad-band sinuous antenna coupled to a Nb microstrip transmission line. In-line filters define the spectral response, allowing for individual measurement of three band-passes (95 GHz, 150GHz and 220 GHz). A Ti /Au termination resistor is used to couple the mm-wave signal to Ti/Au transition edge sensor (TES) bolometers. There are six bolometers per pixel, for a total of 16,140 detectors in the CMB receiver being fabricated. The monolithic microfabrication of the detector arrays will be presented and discussed in detail. The SPT3G collaboration is developing the thrid-generation camera for CMB measurements with the South Pole Telescope. Additional information can be found in the following link: https://pole.uchicago.edu/spt/.

  12. Protein assembly onto patterned microfabricated devices through enzymatic activation of fusion pro-tag.

    PubMed

    Lewandowski, Angela T; Yi, Hyunmin; Luo, Xiaolong; Payne, Gregory F; Ghodssi, Reza; Rubloff, Gary W; Bentley, William E

    2008-02-15

    We report a versatile approach for covalent surface-assembly of proteins onto selected electrode patterns of pre-fabricated devices. Our approach is based on electro-assembly of the aminopolysaccharide chitosan scaffold as a stable thin film onto patterned conductive surfaces of the device, which is followed by covalent assembly of the target protein onto the scaffold surface upon enzymatic activation of the protein's "pro-tag." For our demonstration, the model target protein is green fluorescent protein (GFP) genetically fused with a pentatyrosine pro-tag at its C-terminus, which assembles onto both two-dimensional chips and within fully packaged microfluidic devices in situ and under flow. Our surface-assembly approach enables spatial selectivity and orientational control under mild experimental conditions. We believe that our integrated approach harnessing genetic manipulation, in situ enzymatic activation, and electro-assembly makes it advantageous for a wide variety of bioMEMS and biosensing applications that require facile "biofunctionalization" of microfabricated devices. PMID:17625789

  13. Microfabrication Technology for Large Lekid Arrays: From Nika2 to Future Applications

    NASA Astrophysics Data System (ADS)

    Goupy, J.; Adane, A.; Benoit, A.; Bourrion, O.; Calvo, M.; Catalano, A.; Coiffard, G.; Hoarau, C.; Leclercq, S.; Le Sueur, H.; Macias-Perez, J.; Monfardini, A.; Peck, I.; Schuster, K.

    2016-08-01

    The lumped element kinetic inductance detectors (LEKID) demonstrated full maturity in the New IRAM KID Arrays (NIKA) instrument. These results allow directly comparing LEKID performance with other competing technologies (TES, doped silicon) in the mm and sub-mm range. A continuing effort is ongoing to improve the microfabrication technologies and concepts in order to satisfy the requirements of new instruments. More precisely, future satellites dedicated to cosmic microwave background (CMB) studies will require the same focal plane technology to cover, at least, the frequency range of 60-600 GHz. Aluminium LEKID developed for NIKA have so far demonstrated, under real telescope conditions, a performance approaching photon noise limitation in the band 120-300 GHz. By implementing superconducting bi-layers, we recently demonstrated LEKID arrays working in the range 80-120 GHz and with sensitivities approaching the goals for CMB missions. NIKA itself (350 pixels) is followed by a more ambitious project requiring several thousand (3000-5000) pixels. NIKA2 has been installed in October 2015 at the IRAM 30-m telescope. We will describe in detail the technological improvements that allowed a relatively harmless tenfold up-scaling in pixels count without degrading the initial sensitivity. In particular, we will briefly describe a solution to simplify the difficult fabrication step linked to the slot-line propagation mode in coplanar waveguide.

  14. Thermo-mechanical properties and microfabric of fly ash-stabilized gold tailings.

    PubMed

    Lee, Joon Kyu; Shang, Julie Q; Jeong, Sangseom

    2014-07-15

    This paper studies the changes in thermal conductivity, temperature, and unconfined compressive strength of gold tailings and fly ash mixtures during the curing period of 5 days. The microfabric of the cured mixtures was investigated with mercury intrusion porosimetry (MIP). The mixture samples were prepared at their maximum dry unit weight and optimum moisture content. Effect of adding fly ash to gold tailings (i.e., 0, 20, and 40% of the dry weight of tailings) was examined, and a comparison was made on samples prepared at the same fly ash content by replacing gold tailings with humic acid (i.e., gold tailings and humic acid ratios of 100:0, 90:10, and 80:20 by weight) or by varying pore fluid chemistry (i.e., water and salt solutions of 1M NaCl and CaCl2). The results show that the initial thermal conductivity of the samples is sensitive to the mixture proportion and a declination in the thermal conductivity is observed due to hydration of fly ash and evaporation. Inclusion of fly ash and salts into gold tailings improves the unconfined compressive strength but the presence of humic acid in samples leads to the decrease of the strength. MIP results reveal the pore structure changes associated with the packing states of the samples that reflect the influential factors considered. PMID:24910909

  15. Multiplexed protein detection using antibody-conjugated microbead arrays in a microfabricated electrophoretic device

    PubMed Central

    Barbee, Kristopher D.; Hsiao, Alexander P.; Roller, Eric E.; Huang, Xiaohua

    2011-01-01

    We report the development of a microfabricated electrophoretic device for assembling high-density arrays of antibody-conjugated microbeads for chip-based protein detection. The device consists of a flow cell formed between a gold-coated silicon chip with an array of microwells etched in a silicon dioxide film and a glass coverslip with a series of thin gold counter electrode lines. We have demonstrated that 0.4 and 1 μm beads conjugated with antibodies can be rapidly assembled into the microwells by applying a pulsed electric field across the chamber. By assembling step-wise a mixture of fluorescently labeled antibody-conjugated microbeads, we incorporated both spatial and fluorescence encoding strategies to demonstrate significant multiplexing capabilities. We have shown that these antibody-conjugated microbead arrays can be used to perform on-chip sandwich immunoassays to detect test antigens at concentrations as low as 40 pM (6 ng/mL). A finite element model was also developed to examine the electric field distribution within the device for different counter electrode configurations over a range of line pitches and chamber heights. This device will be useful for assembling high-density, encoded antibody arrays for multiplexed detection of proteins and other types of protein-conjugated microbeads for applications such as the analysis of protein-protein interactions. PMID:20820631

  16. Entrapment of bed bugs by leaf trichomes inspires microfabrication of biomimetic surfaces

    PubMed Central

    Szyndler, Megan W.; Haynes, Kenneth F.; Potter, Michael F.; Corn, Robert M.; Loudon, Catherine

    2013-01-01

    Resurgence in bed bug infestations and widespread pesticide resistance have greatly renewed interest in the development of more sustainable, environmentally friendly methods to manage bed bugs. Historically, in Eastern Europe, bed bugs were entrapped by leaves from bean plants, which were then destroyed; this purely physical entrapment was related to microscopic hooked hairs (trichomes) on the leaf surfaces. Using scanning electron microscopy and videography, we documented the capture mechanism: the physical impaling of bed bug feet (tarsi) by these trichomes. This is distinct from a Velcro-like mechanism of non-piercing entanglement, which only momentarily holds the bug without sustained capture. Struggling, trapped bed bugs are impaled by trichomes on several legs and are unable to free themselves. Only specific, mechanically vulnerable locations on the bug tarsi are pierced by the trichomes, which are located at effective heights and orientations for bed bug entrapment despite a lack of any evolutionary association. Using bean leaves as templates, we microfabricated surfaces indistinguishable in geometry from the real leaves, including the trichomes, using polymers with material properties similar to plant cell walls. These synthetic surfaces snag the bed bugs temporarily but do not hinder their locomotion as effectively as real leaves. PMID:23576783

  17. Microfabrication of patterns of adherent marine bacterium Phaeobacter inhibens using soft lithography and scanning probe lithography.

    PubMed

    Zhao, Chuan; Burchardt, Malte; Brinkhoff, Thorsten; Beardsley, Christine; Simon, Meinhard; Wittstock, Gunther

    2010-06-01

    Two lithographic approaches have been explored for the microfabrication of cellular patterns based on the attachment of marine bacterium Phaeobacter inhibens strain T5. Strain T5 produces a new antibiotic that makes this bacterium potentially interesting for the pharmaceutical market and as a probiotic organism in aquacultures and in controlling biofouling. The microcontact printing (microCP) method is based on the micropatterning of self-assembled monolayers (SAMs) terminated with adhesive end groups such as CH(3) and COOH and nonadhesive groups (e.g., short oligomers of ethylene glycol (OEG)) to form micropatterned substrates for the adhesion of strain T5. The scanning probe lithographic method is based on the surface modification of OEG SAM by using a microelectrode, the probe of a scanning electrochemical microscope (SECM). Oxidizing agents (e.g., Br(2)) were electrogenerated in situ at the microelectrodes from Br(-) in aqueous solution to remove OEG SAMs locally, which allows the subsequent adsorption of bacteria. Various micropatterns of bacteria could be formed in situ on the substrate without a prefabricated template. The fabricated cellular patterns may be applied to a variety of marine biological studies that require the analysis of biofilm formation, cell-cell and cell-surface interactions, and cell-based biosensors and bioelectronics. PMID:20397716

  18. Rapid isothermal substrate microfabrication of a biocompatible thermoplastic elastomer for cellular contact guidance.

    PubMed

    Guillemette, Maxime D; Roy, Emmanuel; Auger, François A; Veres, Teodor

    2011-06-01

    The use of microstructured substrates to study and influence cell orientation, which plays an important role in tissue functionality, has been of great interest lately. Silicon and poly(dimethylsiloxane) substrates have typically been used, but long processing times and exogenous protein surface coating, required to enhance cell viability, limit their use as large-scale platforms. There is thus a need for a non-biodegradable biocompatible substrate that allows rapid and low cost microfabrication. In this paper a styrene-(ethylene/butylene)-styrene block co-polymer (SEBS) microstructured by a rapid replication technique using low pressure an isothermal hot embossing approach has been demonstrated. SEBS substrates were treated with oxygen plasma to enhance cell adhesion and sterilized using ethylene oxide gas. While cell adhesion to and proliferation on these substrates was as good as on tissue culture polystyrene, cellular alignment on microstructured SEBS was also very high (97.7±0.5%) when calculated within a 10° angle variation from the longitudinal axis. Furthermore, tissue sheets on microstructured SEBS have been produced and exhibited cellular alignment within the engineered tissue. In addition, these results were obtained without coating the material with exogenous proteins. Such substrates should be helpful in the culture of tissue engineered substitutes with an intrinsic orientation and to elucidate questions in cell biology. PMID:21329768

  19. New Deep Reactive Ion Etching Process Developed for the Microfabrication of Silicon Carbide

    NASA Technical Reports Server (NTRS)

    Evans, Laura J.; Beheim, Glenn M.

    2005-01-01

    Silicon carbide (SiC) is a promising material for harsh environment sensors and electronics because it can enable such devices to withstand high temperatures and corrosive environments. Microfabrication techniques have been studied extensively in an effort to obtain the same flexibility of machining SiC that is possible for the fabrication of silicon devices. Bulk micromachining using deep reactive ion etching (DRIE) is attractive because it allows the fabrication of microstructures with high aspect ratios (etch depth divided by lateral feature size) in single-crystal or polycrystalline wafers. Previously, the Sensors and Electronics Branch of the NASA Glenn Research Center developed a DRIE process for SiC using the etchant gases sulfur hexafluoride (SF6) and argon (Ar). This process provides an adequate etch rate of 0.2 m/min and yields a smooth surface at the etch bottom. However, the etch sidewalls are rougher than desired, as shown in the preceding photomicrograph. Furthermore, the resulting structures have sides that slope inwards, rather than being precisely vertical. A new DRIE process for SiC was developed at Glenn that produces smooth, vertical sidewalls, while maintaining an adequately high etch rate.

  20. A CMUT probe for medical ultrasonography: from microfabrication to system integration.

    PubMed

    Savoia, Alessandro Stuart; Calianov, Giosuè; Pappalardo, Massimo

    2012-06-01

    Medical ultrasonography is a powerful and cost-effective diagnostic technique. To date, high-end medical imaging systems are able to efficiently implement real-time image formation techniques that can dramatically improve the diagnostic capabilities of ultrasound. Highly performing and thermally efficient ultrasound probes are then required to successfully enable the most advanced techniques. In this context, ultrasound transducer technology is the current limiting factor. Capacitive micromachined ultrasonic transducers (CMUTs) are micro-electro-mechanical systems (MEMS)-based devices that have been widely recognized as a valuable alternative to piezoelectric transducer technology in a variety of medical imaging applications. Wideband operation, good thermal efficiency, and low fabrication cost, especially for those applications requiring high-volume production of small-area dice, are strength factors that may justify the adoption of this MEMS technology in the medical ultrasound imaging field. This paper presents the design, development, fabrication, and characterization of a 12-MHz ultrasound probe for medical imaging, based on a CMUT array. The CMUT array is microfabricated and packed using a novel fabrication concept specifically conceived for imaging transducer arrays. The performance of the developed probe is optimized by including analog front-end reception electronics. Characterization and imaging results are used to assess the performance of CMUTs with respect to conventional piezoelectric transducers. PMID:22711408

  1. Biology on a Chip: Microfabrication for Studying the Behavior of Cultured Cells

    PubMed Central

    Li, Nianzhen; Tourovskaia, Anna; Folch, Albert

    2013-01-01

    The ability to culture cells in vitro has revolutionized hypothesis testing in basic cell and molecular biology research and has become a standard methodology in drug screening and toxicology assays. However, the traditional cell culture methodology—consisting essentially of the immersion of a large population of cells in a homogeneous fluid medium—has become increasingly limiting, both from a fundamental point of view (cells in vivo are surrounded by complex spatiotemporal microenvironments) and from a practical perspective (scaling up the number of fluid handling steps and cell manipulations for high-throughput studies in vitro is prohibitively expensive). Micro fabrication technologies have enabled researchers to design, with micrometer control, the biochemical composition and topology of the substrate, the medium composition, as well as the type of neighboring cells surrounding the microenvironment of the cell. In addition, microtechnology is conceptually well suited for the development of fast, low-cost in vitro systems that allow for high-throughput culturing and analysis of cells under large numbers of conditions. Here we review a variety of applications of microfabrication in cell culture studies, with an emphasis on the biology of various cell types. PMID:15139302

  2. Structural Reinforcement of Cell-Laden Hydrogels with Microfabricated Three Dimensional Scaffolds.

    PubMed

    Cha, Chaenyung; Soman, Pranav; Zhu, Wei; Nikkhah, Mehdi; Camci-Unal, Gulden; Chen, Shaochen; Khademhosseini, Ali

    2014-05-01

    Hydrogels commonly used in tissue engineering are mechanically soft, thus often display structural weakness. Herein, we introduce a strategy for enhancing the structural integrity and fracture toughness of cell-laden hydrogels by incorporating a three-dimensional (3D) microfabricated scaffold as a structural element. A digital micromirror device projection printing (DMD-PP) system, a rapid prototyping technology which employs a layer-by-layer stereolithographic approach, was utilized to efficiently fabricate 3D scaffolds made from photocrosslinkable poly(ethylene glycol) diacrylate (PEGDA). The scaffold was incorporated into a photocrosslinkable gelatin hydrogel by placing it in a pre-gel solution, and inducing in situ hydrogel formation. The resulting scaffold-reinforced hydrogels demonstrated significant increase in ultimate stress and provided structural support for weak hydrogels. In addition, the scaffold did not affect the rigidity of hydrogels, as it was not involved in the crosslinking reaction to form the hydrogel. Therefore, the presented approach could avoid inadvertent and undesired changes in the hydrogel rigidity which is a known regulator of cellular activities. Furthermore, the biocompatibility of scaffold-reinforced hydrogels was confirmed by evaluating the viability and proliferation of encapsulated fibroblasts. Overall, the strategy of incorporating 3D scaffolds into hydrogels as structural reinforcements presented in this study will be highly useful for enhancing the mechanical toughness of hydrogels for various tissue engineering applications. PMID:24778793

  3. A permalloy zigzag structure based magnetic bio-sensor

    NASA Astrophysics Data System (ADS)

    Ger, Tzong-Rong; Xu, You-Ren; Huang, Hao-Ting; Wei, Zung-Hang

    2012-04-01

    A magnetic fluid consisting of Fe3O4 magnetic nanoparticles is embedded inside cells by intracellular uptake. A micro-fabricated magnetic zigzag-shaped surface structure is studied for use as a biosensor. We have developed a MOKE magnetometer based methodology to measure the different hysteresis loop signals between cells with and without being placed on zigzag sensors. Adding the magnetic cells on the structure decreases the coercivity from the magneto-optical Kerr effect (MOKE) signal of zigzag magnetic thin films because of the magnetic properties of superparamagnetic nanoparticles. The magnetoresistance measurement observed is that the switching fields of the zigzag structure with magnetic cells are significantly increased compared to the case without cells in the hard axis of the external field applied.

  4. Macroscopic evidence of nanoscale resistive switching in La2/3Sr1/3MnO3 micro-fabricated bridges

    NASA Astrophysics Data System (ADS)

    Peña, Luis; Garzón, Luis; Galceran, Regina; Pomar, Alberto; Bozzo, Bernat; Konstantinovic, Zorica; Sandiumenge, Felip; Balcells, Lluis; Ocal, Carmen; Martinez, Benjamin

    2014-10-01

    In this work we report on a combined macro, micro and nanoscale investigation where electronic transport properties through La⅔Sr⅓MnO3 (LSMO) microfabricated bridges, in which nano-sized resistive states are induced by using a conducting scanning probe microscope (C-SPM), are analyzed. The strategy intentionally avoids the standard capacitor-like geometry, thus allowing the study of the electronic transport properties of the locally modified region, and approaches the integration of functional oxides in low dimensional devices while providing macroscopic evidence of nanoscale resistive switching (RS). The metallic and ferromagnetic LSMO is locally modified from its low resistance state (LRS) to a high resistance state (HRS) when a bias voltage is applied on its surface through the conducting tip, which acts as a mobile electrode. Starting from a metallic oxide the electroforming process is not required, thus avoiding one of the major drawbacks for the implementation of memory devices based on RS phenomena. The application of a bias voltage generates an electric field that promotes charge depletion, leading to a strong increase of the resistance, i.e. to the HRS. This effect is not only confined to the outermost surface layer, its spatial extension and final HRS condition can be modulated by the magnitude and duration of the potential applied, opening the door to the implementation of multilevel devices. In addition, the half-metallic character, i.e. total spin polarization, of LSMO might allow the implementation of memory elements and active spintronic devices in the very same material. The stability of the HRS and LRS as a function of temperature, magnetic field and compliance current is also analyzed, allowing the characterization of the nature of the switching process and the active material.

  5. Microfabrication of nanoporous gold patterns for cell-material interaction studies.

    PubMed

    Daggumati, Pallavi; Kurtulus, Ozge; Chapman, Christopher Abbott Reece; Dimlioglu, Damla; Seker, Erkin

    2013-01-01

    Nanostructured materials with feature sizes in tens of nanometers have enhanced the performance of several technologies, including fuel cells, biosensors, biomedical device coatings, and drug delivery tools. Nanoporous gold (np-Au), produced by a nano-scale self-assembly process, is a relatively new material that exhibits large effective surface area, high electrical conductivity, and catalytic activity. These properties have made np-Au an attractive material to scientific community. Most studies on np-Au employ macro-scale specimens and focus on fundamental science of the material and its catalytic and sensor applications. The macro-scale specimens limit np-Au's potential in miniaturized systems, including biomedical devices. In order to address these issues, we initially describe two different methods to micropattern np-Au thin films on rigid substrates. The first method employs manually-produced stencil masks for creating millimeter-scale np-Au patterns, while the second method uses lift-off photolithography to pattern sub-millimeter-scale patterns. As the np-Au thin films are obtained by sputter-deposition process, they are compatible with conventional microfabrication techniques, thereby amenable to facile integration into microsystems. These systems include electrically-addressable biosensor platforms that benefit from high effective surface area, electrical conductivity, and gold-thiol-based surface bioconjugation. We describe cell culture, immunostaining, and image processing techniques to quantify np-Au's interaction with mammalian cells, which is an important performance parameter for some biosensors. We expect that the techniques illustrated here will assist the integration of np-Au in platforms at various length-scales and in numerous applications, including biosensors, energy storage systems, and catalysts. PMID:23893025

  6. Grain trapping by filamentous cyanobacterial and algal mats: implications for stromatolite microfabrics through time.

    PubMed

    Frantz, C M; Petryshyn, V A; Corsetti, F A

    2015-09-01

    Archean and Proterozoic stromatolites are sparry or fine-grained and finely laminated; coarse-grained stromatolites, such as many found in modern marine systems, do not appear until quite late in the fossil record. The cause of this textural change and its relevance to understanding the evolutionary history of stromatolites is unclear. Cyanobacteria are typically considered the dominant stromatolite builders through time, but studies demonstrating the trapping and binding abilities of cyanobacterial mats are limited. With this in mind, we conducted experiments to test the grain trapping and binding capabilities of filamentous cyanobacterial mats and trapping in larger filamentous algal mats in order to better understand grain size trends in stromatolites. Mats were cut into squares, inclined in saltwater tanks at angles from 0 to 75° (approximating the angle of lamina in typical stromatolites), and grains of various sizes (fine sand, coarse sand, and fine pebbles) were delivered to their surface. Trapping of grains by the cyanobacterial mats depended strongly on (i) how far filaments protruded from the sediment surface, (ii) grain size, and (iii) the mat's incline angle. The cyanobacterial mats were much more effective at trapping fine grains beyond the abiotic slide angle than larger grains. In addition, the cyanobacterial mats actively bound grains of all sizes over time. In contrast, the much larger algal mats trapped medium and coarse grains at all angles. Our experiments suggest that (i) the presence of detrital grains beyond the abiotic slide angle can be considered a biosignature in ancient stromatolites where biogenicity is in question, and, (ii) where coarse grains are present within stromatolite laminae at angles beyond the abiotic angle of slide (e.g., most modern marine stromatolites), typical cyanobacterial-type mats are probably not solely responsible for the construction, giving insight into the evolution of stromatolite microfabrics through time

  7. Aging studies on micro-fabricated alkali buffer-gas cells for miniature atomic clocks

    SciTech Connect

    Abdullah, S.; Affolderbach, C.; Gruet, F.; Mileti, G.

    2015-04-20

    We report an aging study on micro-fabricated alkali vapor cells using neon as a buffer gas. An experimental atomic clock setup is used to measure the cell's intrinsic frequency, by recording the clock frequency shift at different light intensities and extrapolating to zero intensity. We find a drift of the cell's intrinsic frequency of (−5.2 ± 0.6) × 10{sup −11}/day and quantify deterministic variations in sources of clock frequency shifts due to the major physical effects to identify the most probable cause of the drift. The measured drift is one order of magnitude stronger than the total frequency variations expected from clock parameter variations and corresponds to a slow reduction of buffer gas pressure inside the cell, which is compatible with the hypothesis of loss of Ne gas from the cell due to its permeation through the cell windows. A negative drift on the intrinsic cell frequency is reproducible for another cell of the same type. Based on the Ne permeation model and the measured cell frequency drift, we determine the permeation constant of Ne through borosilicate glass as (5.7 ± 0.7) × 10{sup −22} m{sup 2} s{sup −1 }Pa{sup −1} at 81 °C. We propose this method based on frequency metrology in an alkali vapor cell atomic clock setup based on coherent population trapping for measuring permeation constants of inert gases.

  8. A microfabricated optofluidic ring resonator for sensitive, high-speed detection of volatile organic compounds.

    PubMed

    Scholten, Kee; Fan, Xudong; Zellers, Edward T

    2014-10-01

    Advances in microanalytical systems for multi-vapor determinations to date have been impeded by limitations associated with the microsensor technologies employed. Here we introduce a microfabricated optofluidic ring resonator (μOFRR) sensor that addresses many of these limitations. The μOFRR combines vapor sensing and fluidic transport functions in a monolithic microstructure comprising a hollow, vertical SiOx cylinder (250 μm i.d., 1.2 μm wall thickness; 85 μm height) with a central quasi-toroidal mode-confinement section, grown and partially released from a Si substrate. The device also integrates on-chip fluidic-interconnection and fiber-optic probe alignment features. High-Q whispering gallery modes generated with a tunable 1550 nm laser exhibit rapid, reversible shifts in resonant wavelength arising from polymer swelling and refractive index changes as vapors partition into the ~300 nm PDMS film lining the cylinder. Steady-state sensor responses varied in proportion to concentration over a 50-fold range for the five organic vapors tested, providing calculated detection limits as low as 0.5 ppm (v/v) (for m-xylene and ethylbenzene). In dynamic exposure tests, responses to 5 μL injected m-xylene vapor pulses were 710 ms wide and were only 18% broader than those from a reference flame-ionization detector and also varied linearly with injected mass; 180 pg was measured and the calculated detection limit was 49 pg without use of preconcentration or split injection, at a flow rate compatible with efficient chromatographic separations. Coupling of this μOFRR with a micromachined gas chromatographic separation column is demonstrated. PMID:25131718

  9. Microfabricated plastic chips by hot embossing methods and their applications for DNA separation and detection

    NASA Astrophysics Data System (ADS)

    Lee, Gwo-Bin; Chen, Shu-Hui; Huang, Guan-Ruey; Lin, Yen-Heng; Sung, Wang-Chou

    2000-08-01

    Design and fabrication of microfluidic devices on polymethylmethacrylate (PMMA) substrates using novel microfabrication methods are described. The image of microfluidic devices is transferred from quartz master templates possessing inverse image of the devices to plastic plates by using hot embossing method. The micro channels on master templates are formed by the combination of metal etch mask and wet chemical etching. The micromachined quartz templates can be used repeatedly to fabricate cheap and disposable plastic devices. The reproducibility of the hot embossing method is evaluated after using 10 channels on different plastics. The relative standard deviation of the plastic channel profile from ones on quartz templates is less than 1%. In this study, the PMMA chips have been demonstrated as a micro capillary electrophoresis ((mu) -CE) device for DNA separation and detection. The capability of the fabricated chip for electrophoretic injection and separation is characterized via the analysis of DNA fragments (phi) X174. Results indicate that all of the 11 DNA fragments of the size marker could be identified in less than 3 minutes with relative standard deviations less than 0.4% and 8% for migration time and peak area, respectively. Moreover, with the use of near IR dye, fluorescence signals of the higher molecular weight fragments ($GTR 603 bp in length) could be detected at total DNA concentrations as low as 0.1 (mu) g/mL. In addition to DNA fragments (phi) X174, DNA sizing of hepatitis C viral (HCV) amplicon is also achieved using microchip electrophoresis fabricated on PMMA substrate.

  10. Microfabrication of Nanoporous Gold Patterns for Cell-material Interaction Studies

    PubMed Central

    Daggumati, Pallavi; Kurtulus, Ozge; Chapman, Christopher Abbott Reece; Dimlioglu, Damla; Seker, Erkin

    2013-01-01

    Nanostructured materials with feature sizes in tens of nanometers have enhanced the performance of several technologies, including fuel cells, biosensors, biomedical device coatings, and drug delivery tools. Nanoporous gold (np-Au), produced by a nano-scale self-assembly process, is a relatively new material that exhibits large effective surface area, high electrical conductivity, and catalytic activity. These properties have made np-Au an attractive material to scientific community. Most studies on np-Au employ macro-scale specimens and focus on fundamental science of the material and its catalytic and sensor applications. The macro-scale specimens limit np-Au's potential in miniaturized systems, including biomedical devices. In order to address these issues, we initially describe two different methods to micropattern np-Au thin films on rigid substrates. The first method employs manually-produced stencil masks for creating millimeter-scale np-Au patterns, while the second method uses lift-off photolithography to pattern sub-millimeter-scale patterns. As the np-Au thin films are obtained by sputter-deposition process, they are compatible with conventional microfabrication techniques, thereby amenable to facile integration into microsystems. These systems include electrically-addressable biosensor platforms that benefit from high effective surface area, electrical conductivity, and gold-thiol-based surface bioconjugation. We describe cell culture, immunostaining, and image processing techniques to quantify np-Au's interaction with mammalian cells, which is an important performance parameter for some biosensors. We expect that the techniques illustrated here will assist the integration of np-Au in platforms at various length-scales and in numerous applications, including biosensors, energy storage systems, and catalysts. PMID:23893025

  11. In Vitro Reconstruction of Neuronal Networks Derived from Human iPS Cells Using Microfabricated Devices.

    PubMed

    Takayama, Yuzo; Kida, Yasuyuki S

    2016-01-01

    Morphology and function of the nervous system is maintained via well-coordinated processes both in central and peripheral nervous tissues, which govern the homeostasis of organs/tissues. Impairments of the nervous system induce neuronal disorders such as peripheral neuropathy or cardiac arrhythmia. Although further investigation is warranted to reveal the molecular mechanisms of progression in such diseases, appropriate model systems mimicking the patient-specific communication between neurons and organs are not established yet. In this study, we reconstructed the neuronal network in vitro either between neurons of the human induced pluripotent stem (iPS) cell derived peripheral nervous system (PNS) and central nervous system (CNS), or between PNS neurons and cardiac cells in a morphologically and functionally compartmentalized manner. Networks were constructed in photolithographically microfabricated devices with two culture compartments connected by 20 microtunnels. We confirmed that PNS and CNS neurons connected via synapses and formed a network. Additionally, calcium-imaging experiments showed that the bundles originating from the PNS neurons were functionally active and responded reproducibly to external stimuli. Next, we confirmed that CNS neurons showed an increase in calcium activity during electrical stimulation of networked bundles from PNS neurons in order to demonstrate the formation of functional cell-cell interactions. We also confirmed the formation of synapses between PNS neurons and mature cardiac cells. These results indicate that compartmentalized culture devices are promising tools for reconstructing network-wide connections between PNS neurons and various organs, and might help to understand patient-specific molecular and functional mechanisms under normal and pathological conditions. PMID:26848955

  12. Investigations into the chemical structure based selectivity of the microfabricated nitrogen-phosphorus detector

    SciTech Connect

    Brocato, Terisse A.; Hess, Ryan F.; Moorman, Matthew; Simonson, Robert J.

    2015-10-28

    The nitrogen and phosphorus atoms are constituents of some of the most toxic chemical vapors. Nitrogen-phosphorus gas chromatograph detectors (NPDs) rely on selective ionization of such compounds using ionization temperatures typically greater than 600 °C. NPDs have previously been reported to be 7*104× and 105× more sensitive for nitrogen and phosphorus, respectively, than for carbon. Presented here is an investigation of the structure-based selectivity of a microfabricated nitrogen-phosphorus detector (μNPD). The μNPD presented here is smaller than a dime and can be placed in a system that is 1/100th the size of a commercial NPD. Comparison of responses of such devices to homologous anilines (p-methoxyaniline, p-fluoroaniline, and aniline) revealed that detection selectivity, determined by the ratio of μNPD to nonselective flame ionization detector (FID) peak areas, is correlated with acid disassociation pKa values for the respective analine. Selectivity was determined to be greatest for p-methoxyaniline, followed by p-fluoroaniline, with aniline having the smallest response. The limit of detection for a nitrogen containing chemical, p-methoxyaniline, using the μNPD was determined to be 0.29 ng compared to 59 ng for a carbon chemical containing no nitrogen or phosphorus, 1,3,5-trimethybenzene. The μNPD presented here has increased detection for nitrogen and phosphorus compared to the FID and with a slight increase in detection of carbon compounds compared to commercial NPD's sensitivity to nitrogen and carbon.

  13. Investigations into the chemical structure based selectivity of the microfabricated nitrogen-phosphorus detector

    DOE PAGESBeta

    Brocato, Terisse A.; Hess, Ryan F.; Moorman, Matthew; Simonson, Robert J.

    2015-10-28

    The nitrogen and phosphorus atoms are constituents of some of the most toxic chemical vapors. Nitrogen-phosphorus gas chromatograph detectors (NPDs) rely on selective ionization of such compounds using ionization temperatures typically greater than 600 °C. NPDs have previously been reported to be 7*104× and 105× more sensitive for nitrogen and phosphorus, respectively, than for carbon. Presented here is an investigation of the structure-based selectivity of a microfabricated nitrogen-phosphorus detector (μNPD). The μNPD presented here is smaller than a dime and can be placed in a system that is 1/100th the size of a commercial NPD. Comparison of responses of suchmore » devices to homologous anilines (p-methoxyaniline, p-fluoroaniline, and aniline) revealed that detection selectivity, determined by the ratio of μNPD to nonselective flame ionization detector (FID) peak areas, is correlated with acid disassociation pKa values for the respective analine. Selectivity was determined to be greatest for p-methoxyaniline, followed by p-fluoroaniline, with aniline having the smallest response. The limit of detection for a nitrogen containing chemical, p-methoxyaniline, using the μNPD was determined to be 0.29 ng compared to 59 ng for a carbon chemical containing no nitrogen or phosphorus, 1,3,5-trimethybenzene. The μNPD presented here has increased detection for nitrogen and phosphorus compared to the FID and with a slight increase in detection of carbon compounds compared to commercial NPD's sensitivity to nitrogen and carbon.« less

  14. UV-LIGA microfabrication process for sub-terahertz waveguides utilizing multiple layered SU-8 photoresist

    NASA Astrophysics Data System (ADS)

    Malekabadi, Ali; Paoloni, Claudio

    2016-09-01

    A microfabrication process based on UV LIGA (German acronym of lithography, electroplating and molding) is proposed for the fabrication of relatively high aspect ratio sub-terahertz (100–1000 GHz) metal waveguides, to be used as a slow wave structure in sub-THz vacuum electron devices. The high accuracy and tight tolerances required to properly support frequencies in the sub-THz range can be only achieved by a stable process with full parameter control. The proposed process, based on SU-8 photoresist, has been developed to satisfy high planar surface requirements for metal sub-THz waveguides. It will be demonstrated that, for a given thickness, it is more effective to stack a number of layers of SU-8 with lower thickness rather than using a single thick layer obtained at lower spin rate. The multiple layer approach provides the planarity and the surface quality required for electroforming of ground planes or assembly surfaces and for assuring low ohmic losses of waveguides. A systematic procedure is provided to calculate soft and post-bake times to produce high homogeneity SU-8 multiple layer coating as a mold for very high quality metal waveguides. A double corrugated waveguide designed for 0.3 THz operating frequency, to be used in vacuum electronic devices, was fabricated as test structure. The proposed process based on UV LIGA will enable low cost production of high accuracy sub-THz 3D waveguides. This is fundamental for producing a new generation of affordable sub-THz vacuum electron devices, to fill the technological gap that still prevents a wide diffusion of numerous applications based on THz radiation.

  15. Calibration of AFM cantilever stiffness: a microfabricated array of reflective springs.

    PubMed

    Cumpson, P J Peter J; Zhdan, Peter; Hedley, John

    2004-08-01

    Calibration of the spring constant of atomic force microscope (AFM) cantilevers is necessary for the measurement of nanonewton and piconewton forces, which are critical to analytical applications of AFM in the analysis of polymer surfaces, biological structures and organic molecules. We have developed a compact and easy-to-use reference standard for this calibration. The new artifact consists of an array of 12 dual spiral-cantilever springs, each supporting a mirrored polycrystalline silicon disc of 160 microm in diameter. These devices were fabricated by a three-layer polysilicon surface micromachining method, including a reflective layer of gold on chromium. We call such an array a Microfabricated Array of Reference Springs (MARS). These devices have a number of advantages. Cantilever calibration using this device is straightforward and rapid. The devices have very small inertia, and are therefore resistant to shock and vibration. This means they need no careful treatment except reasonably clean laboratory conditions. The array spans the range of spring constant from around 0.16 to 11 N/m important in AFM, allowing almost all contact-mode AFM cantilevers to be calibrated easily and rapidly. Each device incorporates its own discrete gold mirror to improve reflectivity. The incorporation of a gold mirror both simplifies calibration of the devices themselves (via Doppler velocimetry) and allows interferometric calibration of the AFM z-axis using the apparent periodicity in the force-distance curve before contact. Therefore, from a single force-distance curve, taking about one second to acquire, one can calibrate the cantilever spring constant and, optionally, the z-axis scale. These are all the data one needs to make accurate and reliable force measurements. PMID:15231316

  16. In Vitro Reconstruction of Neuronal Networks Derived from Human iPS Cells Using Microfabricated Devices

    PubMed Central

    Takayama, Yuzo; Kida, Yasuyuki S.

    2016-01-01

    Morphology and function of the nervous system is maintained via well-coordinated processes both in central and peripheral nervous tissues, which govern the homeostasis of organs/tissues. Impairments of the nervous system induce neuronal disorders such as peripheral neuropathy or cardiac arrhythmia. Although further investigation is warranted to reveal the molecular mechanisms of progression in such diseases, appropriate model systems mimicking the patient-specific communication between neurons and organs are not established yet. In this study, we reconstructed the neuronal network in vitro either between neurons of the human induced pluripotent stem (iPS) cell derived peripheral nervous system (PNS) and central nervous system (CNS), or between PNS neurons and cardiac cells in a morphologically and functionally compartmentalized manner. Networks were constructed in photolithographically microfabricated devices with two culture compartments connected by 20 microtunnels. We confirmed that PNS and CNS neurons connected via synapses and formed a network. Additionally, calcium-imaging experiments showed that the bundles originating from the PNS neurons were functionally active and responded reproducibly to external stimuli. Next, we confirmed that CNS neurons showed an increase in calcium activity during electrical stimulation of networked bundles from PNS neurons in order to demonstrate the formation of functional cell-cell interactions. We also confirmed the formation of synapses between PNS neurons and mature cardiac cells. These results indicate that compartmentalized culture devices are promising tools for reconstructing network-wide connections between PNS neurons and various organs, and might help to understand patient-specific molecular and functional mechanisms under normal and pathological conditions. PMID:26848955

  17. Enhanced electroanalysis in lithium potassium eutectic (LKE) using microfabricated square microelectrodes.

    PubMed

    Corrigan, Damion K; Blair, Ewen O; Terry, Jonathan G; Walton, Anthony J; Mount, Andrew R

    2014-11-18

    Molten salts (MSs) are an attractive medium for chemical and electrochemical processing and as a result there is demand for MS-compatible analysis technologies. However, MSs containing redox species present a challenging environment in which to perform analytical measurements because of their corrosive nature, significant thermal convection and the high temperatures involved. This paper outlines the fabrication and characterization of microfabricated square microelectrodes (MSMs) designed for electrochemical analysis in MS systems. Their design enables precise control over electrode dimension, the minimization of stress because of differential thermal expansion through design for high temperature operation, and the minimization of corrosive attack through effective insulation. The exemplar MS system used for characterization was lithium chloride/potassium chloride eutectic (LKE), which has potential applications in pyrochemical nuclear fuel reprocessing, metal refining, molten salt batteries and electric power cells. The observed responses for a range of redox ions between 400 and 500 °C (673 and 773 K) were quantitative and typical of microelectrodes. MSMs also showed the reduced iR drop, steady-state diffusion-limited response, and reduced sensitivity to convection seen for microelectrodes under ambient conditions and expected for these electrodes in comparison to macroelectrodes. Diffusion coefficients were obtained in close agreement with literature values, more readily and at greater precision and accuracy than both macroelectrode and previous microelectrode measurements. The feasibility of extracting individual physical parameters from mixtures of redox species (as required in reprocessing) and of the prolonged measurement required for online monitoring was also demonstrated. Together, this demonstrates that MSMs provide enhanced electrode devices widely applicable to the characterization of redox species in a range of MS systems. PMID:25284431

  18. Microfabricated ion trap mass spectrometry for characterization of organics and potential biomarkers

    NASA Astrophysics Data System (ADS)

    Austin, Daniel

    Mass spectrometry is a powerful analytical technique with a strong history in planetary exploration, and is the method of choice for detection and identification of organic and biological molecules. MS instrumentation can also be combined with techniques such as gas chromatography, liquid chromatography, or chiral separation, which are particularly important for analysis of complex mixtures or possible homochirality. Ion traps have several inherent advantages, including speed of analysis (important for GC-MS), MS/MS capabilities (important to identification of unknown compounds), excellent sensitivity, and ease of coupling with ambient ionization techniques that are under development for biomolecule detection. We report on progress in using microfabrication techniques to produce radiofrequency quadrupole ion traps that are much smaller, lighter, and lower power than existing instruments. We produce ion traps using an assembly of two ceramic plates, the facing surfaces of which are lithographically patterned with electrodes. This approach allows great flexibility in the trap geometry, and we have demonstrated working mass spectrometers with quadrupole, linear, and toroidal trapping fields. The approach also allows correction of higher-order terms in the electric field. With this system, mass resolution of up to 1300 has been demonstrated, which is adequate for identification of a wide range of potential biomarkers. Capabilities such as tandem analysis have also been demonstrated. Of particular interest is an ion trap that contains both quadrupole and toroidal trapping regions simultaneously and coaxially. Ions can be trapped as a large reservoir in the toroidal region and introduced in small batches to the quadrupole region for mass analysis. This capability is particularly valuable where the sample of interest is very small, such as microfossil with trace organics, and where the organic inventory is both complex and unknown. Development and results of this device

  19. Microfabrication of air core power inductors with metal-encapsulated polymer vias

    SciTech Connect

    Kim, J; Herrault, F; Yu, XH; Kim, M; Shafer, RH; Allen, MG

    2013-01-25

    This paper reports three-dimensional (3-D) microfabricated toroidal inductors intended for power electronics applications. A key fabrication advance is the exploitation of thick metal encapsulation of polymer pillars to form a vertical via interconnections. The radial conductors of the toroidal inductor are formed by conventional plating-through-mold techniques, while the vertical windings (up to 650 mu m in height) are formed by polymer cores with metal plated on their external surfaces. This encapsulated polymer approach not only significantly reduces the required plating time but also exploits the relative ease of fabricating high-aspect-ratio SU-8 pillars. To form the top radial conductors, non-photopatternable SU-8 is introduced as a thick sacrificial layer. Two toroidal inductor geometries were fabricated and tested. The first inductor had an inner diameter of 2 mm, an outer diameter of 6 mm, 25 turns and a vertical via height of 650 mu m. The second inductor had an inner diameter of 4 mm, an outer diameter of 8 mm, 50 turns and a vertical via height of 650 mu m. Both inductor geometries were successfully fabricated and characterized in the frequency range of 0.1-100 MHz. Characterization results of the 25- and 50-turn inductors showed an average inductance of 76 and 200 nH, a low frequency (0.1 MHz) resistance of 0.2 and 1 Omega and a quality factor of 35 and 24 at 100 MHz, respectively. Finite-element simulations of the inductors were performed and agreed with the measured results to within 8%. The turn-to-turn breakdown voltage was measured to be in excess of 800 V and currents as high as 0.5 A could be successfully carried by the inductor windings.

  20. Magnetic Tools for Lab-on-a-chip Technologies

    SciTech Connect

    Nikola Slobodan Pekas

    2006-08-05

    This study establishes a set of magnetics-based tools that have been integrated with microfluidic systems. The overall impact of the work begins to enable the rapid and efficient manipulation and detection of magnetic entities such as particles, picoliter-sized droplets, or bacterial cells. Details of design, fabrication, and theoretical and experimental assessments are presented. The manipulation strategy has been demonstrated in the format of a particle diverter, whereby micron-sized particles are actively directed into desired flow channels at a split-flow junction by means of integrated microelectromagnets. Magnetic detection has been realized by deploying Giant Magnetoresistance (GMR) sensors--microfabricated structures originally developed for use as readout elements in computer hard-drives. We successfully transferred the GMR technology to the lab-on-a-chip arena, and demonstrated the versatility of the concept in several important areas: real-time, integrated monitoring of the properties of multiphase droplet flows; rapid quantitative determination of the concentration of magnetic nanoparticles in droplets of ferrofluids; and high-speed detection of individual magnetic microparticles and magnetotactic bacteria. The study also includes novel schemes for hydrodynamic flow focusing that work in conjunction with GMR-based detection to ensure precise navigation of the sample stream through the GMR detection volume, therefore effectively establishing a novel concept of a microfabricated magnetic flow cytometer.

  1. Reliability characteristics of microfabricated Rb mini-lamps for optical pumping in miniature atomic clocks and magnetometers

    NASA Astrophysics Data System (ADS)

    Venkatraman, Vinu; Pétremand, Yves; de Rooij, Nico; Shea, Herbert

    2013-03-01

    With the rising need for microfabricated chip-scale atomic clocks to enable high precision timekeeping in portable applications, there has been active interest in developing miniature (microfabricated chip-scale Rubidium dielectric barrier discharge lamp. The device's preliminary results indicated its high potential for optical pumping applications and wafer-scale batch fabrication. The chip-scale plasma light sources were observed to be robust with no obvious performance change after thousands of plasma ignitions, and with no electrode erosion from plasma discharges since the electrodes are external. However, as atomic clocks have strict lamp performance requirements including less than 0.1% sub-second optical power fluctuations, power consumption less than 20 mW and a device lifetime of at least several years, it is important to understand the long-term reliability of these Rb planar mini-lamps, and identify the operating conditions where these devices can be most reliable and stable. In this paper, we report on the reliability of such microfabricated lamps including a continuous several month run of the lamp where the optical power, electrical power consumption and temperature stability were continuously monitored. We also report on the effects of temperature, rf-power and the lamp-drive parasitics on the optical power stability and discuss steps that could be taken to further improve the device's performance and reliability.

  2. The particle valve: On-demand particle trapping, filtering, and release from a microfabricated polydimethylsiloxane membrane using surface acoustic waves

    NASA Astrophysics Data System (ADS)

    Collins, David J.; Alan, Tuncay; Neild, Adrian

    2014-07-01

    We introduce a surface acoustic wave (SAW) based method for acoustically controlled concentration, capture, release, and sorting of particles in a microfluidic system. This method is power efficient by the nature of its design: the vertical direction of a traveling acoustic wave, in which the majority of the energy at the SAW-water interface is directed, is used to concentrate particles behind a microfabricated polydimethylsiloxane membrane extending partially into a channel. Sorting is also demonstrated with this concentration shown to be size-dependent. Low-power, miniature SAW devices, using methods such as the one demonstrated here, are well placed for future integration into point-of-care diagnostic systems.

  3. Selective coupling of HE11 and TM01 modes into microfabricated fully metal-coated quartz probes.

    PubMed

    Tortora, P; Descrovi, E; Aeschimann, L; Vaccaro, L; Herzig, H-P; Dändliker, R

    2007-01-01

    We report computational and experimental investigations on injection and transmission of light in microfabricated fully Aluminum-coated quartz probes. In particular, we show that a selective coupling of either the HE(11) or the TM(01) mode can be carried out by injecting focused linearly or radially polarized beams into the probe. Optical fields, emitted by the probe after a controlled injection, are characterized in intensity and phase with the help of an interferometric technique. With the help of near-field measurement, we finally demonstrate that a longitudinally polarized spot localized at the tip apex is actually produced when the TM(01) mode is coupled into the probe. PMID:16942840

  4. Carbonate fabrics in the modern microbialites of Pavilion Lake: two suites of microfabrics that reflect variation in microbial community morphology, growth habit, and lithification.

    PubMed

    Theisen, C Harwood; Sumner, D Y; Mackey, T J; Lim, D S S; Brady, A L; Slater, G F

    2015-07-01

    Modern microbialites in Pavilion Lake, BC, provide an analog for ancient non-stromatolitic microbialites that formed from in situ mineralization. Because Pavilion microbialites are mineralizing under the influence of microbial communities, they provide insights into how biological processes influence microbialite microfabrics and mesostructures. Hemispherical nodules and micrite-microbial crusts are two mesostructures within Pavilion microbialites that are directly associated with photosynthetic communities. Both filamentous cyanobacteria in hemispherical nodules and branching filamentous green algae in micrite-microbial crusts were associated with calcite precipitation at microbialite surfaces and with characteristic microfabrics in the lithified microbialite. Hemispherical nodules formed at microbialite surfaces when calcite precipitated around filamentous cyanobacteria with a radial growth habit. The radial filament pattern was preserved within the microbialite to varying degrees. Some subsurface nodules contained well-defined filaments, whereas others contained only dispersed organic inclusions. Variation in filament preservation is interpreted to reflect differences in timing and amount of carbonate precipitation relative to heterotrophic decay, with more defined filaments reflecting greater lithification prior to degradation than more diffuse filaments. Micrite-microbial crusts produce the second suite of microfabrics and form in association with filamentous green algae oriented perpendicular to the microbialite surface. Some crusts include calcified filaments, whereas others contained voids that reflect the filamentous community in shape, size, and distribution. Pavilion microbialites demonstrate that microfabric variation can reflect differences in lithification processes and microbial metabolisms as well as microbial community morphology and organization. Even when the morphology of individual filaments or cells is not well preserved, the microbial growth

  5. Self-assembled magnetic filter for highly efficient immunomagnetic separation.

    PubMed

    Issadore, David; Shao, Huilin; Chung, Jaehoon; Newton, Andita; Pittet, Mikael; Weissleder, Ralph; Lee, Hakho

    2011-01-01

    We have developed a compact and inexpensive microfluidic chip, the self-assembled magnetic filter, to efficiently remove magnetically tagged cells from suspension. The self-assembled magnetic filter consists of a microfluidic channel built directly above a self-assembled NdFeB magnet. Micrometre-sized grains of NdFeB assemble to form alternating magnetic dipoles, creating a magnetic field with a very strong magnitude B (from the material) and field gradient ▽B (from the configuration) in the microfluidic channel. The magnetic force imparted on magnetic beads is measured to be comparable to state-of-the-art microfabricated magnets, allowing for efficient separations to be performed in a compact, simple device. The efficiency of the magnetic filter is characterized by sorting non-magnetic (polystyrene) beads from magnetic beads (iron oxide). The filter enriches the population of non-magnetic beads to magnetic beads by a factor of >10(5) with a recovery rate of 90% at 1 mL h(-1). The utility of the magnetic filter is demonstrated with a microfluidic device that sorts tumor cells from leukocytes using negative immunomagnetic selection, and concentrates the tumor cells on an integrated membrane filter for optical detection. PMID:20949198

  6. Minature Nuclear Magnetic Resonance Spectrometer for In-situ and In-Process Analysis and Monitoring

    SciTech Connect

    Gennady Friedman

    2004-05-04

    The effort in this project has been in 3 distinct directions. (1) First, we focused on development of minature microfabricated micro-coil NMR detectors with maximum Signal-to-Noise (SNR) ratio. (2) Secondly, we focused on design of minature micro-coil NMR detectors that have minimal effect on the NMR spectrum distortions. (3) Lastly we focused on the development of a permanent magnet capable of generating fields on the order of 1 Tesla with better than 10 ppm uniformity.

  7. DNA templated magnetic nanoparticles

    NASA Astrophysics Data System (ADS)

    Kinsella, Joseph M.

    Recent discoveries in nanoscience are predicted to potentially revolutionize future technologies in an extensive number of fields. These developments are contingent upon discovering new and often unconventional methods to synthesize and control nanoscale components. Nature provides several examples of working nanotechnology such as the use of programmed self assembly to build and deconstruct complex molecular systems. We have adopted a method to control the one dimensional assembly of magnetic nanoparticles using DNA as a scaffold molecule. With this method we have demonstrated the ability to organize 5 nm particles into chains that stretch up to ˜20 mum in length. One advantage of using DNA compared is the ability of the molecule to interact with other biomolecules. After assembling particles onto DNA we have been able to cleave the molecule into smaller fragments using restriction enzymes. Using ligase enzymes we have re-connected these fragments, coated with either gold or iron oxide, to form long one-dimensional arrangements of the two different types of nanoparticles on a single molecular guide. We have also created a sensitive magnetic field sensor by incorporating magnetic nanoparticle coated DNA strands with microfabricated electrodes. The IV characteristics of the aligned nanoparticles are dependant on the magnitude of an externally applied magnetic field. This transport phenomenon known as tunneling magnetoresistance (TMR) shows room temperature resistance of our devices over 80% for cobalt ferrite coated DNA when a field of 20 kOe is applied. In comparison, studies using two dimensional nanoparticle films of irox oxides xii only exhibit a 35% MR effect. Confinement into one dimension using the DNA guide produces a TMR mechanism which produces significant increases in magnetoresistance. This property can be utilized for applications in magnetic field sensing, data storage, and logic elements.

  8. A Scalable Perfusion Culture System with Miniature Peristaltic Pumps for Live-Cell Imaging Assays with Provision for Microfabricated Scaffolds

    PubMed Central

    Balakrishnan, Sreenath; Suma, M.S.; Raju, Shilpa R.; Bhargav, Santosh D.B.; Arunima, S.; Das, Saumitra

    2015-01-01

    Abstract We present a perfusion culture system with miniature bioreactors and peristaltic pumps. The bioreactors are designed for perfusion, live-cell imaging studies, easy incorporation of microfabricated scaffolds, and convenience of operation in standard cell culture techniques. By combining with miniature peristaltic pumps—one for each bioreactor to avoid cross-contamination and to maintain desired flow rate in each—we have made a culture system that facilitates perfusion culture inside standard incubators. This scalable system can support multiple parallel perfusion experiments. The major components are fabricated by three-dimensional printing using VeroWhite, which we show to be amenable to ex vivo cell culture. Furthermore, the components of the system can be reused, thus making it economical. We validate the system and illustrate its versatility by culturing primary rat hepatocytes, live imaging the growth of mouse fibroblasts (NIH 3T3) on microfabricated ring-scaffolds inserted into the bioreactor, performing perfusion culture of breast cancer cells (MCF7), and high-magnification imaging of hepatocarcinoma cells (HuH7). PMID:26309810

  9. Transparent magnetic photoresists for bioanalytical applications.

    PubMed

    Gach, Philip C; Sims, Christopher E; Allbritton, Nancy L

    2010-11-01

    Microfabricated devices possessing magnetic properties are of great utility in bioanalytical microdevices due to their controlled manipulation with external magnets. Current methods for creating magnetic microdevices yield a low-transparency material preventing light microscopy-based inspection of biological specimens on the structures. Uniformly transparent magnetic photoresists were developed for microdevices that require high transparency as well as consistent magnetism across the structure. Colloidal formation of 10 nm maghemite particles was minimized during addition to the negative photoresists SU-8 and 1002F through organic capping of the nanoparticles and utilization of solvent-based dispersion techniques. Photoresists with maghemite concentrations of 0.01-1% had a high transparency due to the even dispersal of maghemite nanoparticles within the polymer as observed with transmission electron microscopy (TEM). These magnetic photoresists were used to fabricate microstructures with aspect ratios up to 4:1 and a resolution of 3 μm. Various cell lines showed excellent adhesion and viability on the magnetic photoresists. An inspection of cells cultured on the magnetic photoresists with TEM showed cellular uptake of magnetic nanoparticles leeched from the photoresists. Cellular contamination by magnetic nanoparticles was eliminated by capping the magnetic photoresist surface with native 1002F photoresist or by removing the top layer of the magnetic photoresist through surface roughening. The utility of these magnetic photoresists was demonstrated by sorting single cells (HeLa, RBL and 3T3 cells) cultured on arrays of releasable magnetic micropallets. 100% of magnetic micropallets with attached cells were collected following release from the array. 85-92% of the collected cells expanded into colonies. The polymeric magnetic materials should find wide use in the fabrication of microstructures for bioanalytical technologies. PMID:20719380

  10. Structures, microfabrics and textures of the Cordilleran-type Rechnitz metamorphic core complex, Eastern Alps☆

    PubMed Central

    Cao, Shuyun; Neubauer, Franz; Bernroider, Manfred; Liu, Junlai; Genser, Johann

    2013-01-01

    Rechnitz window group represents a Cordilleran-style metamorphic core complex, which is almost entirely located within nearly contemporaneous Neogene sediments at the transition zone between the Eastern Alps and the Neogene Pannonian basin. Two tectonic units are distinguished within the Rechnitz metamorphic core complex (RMCC): (1) a lower unit mainly composed of Mesozoic metasediments, and (2) an upper unit mainly composed of ophiolite remnants. Both units are metamorphosed within greenschist facies conditions during earliest Miocene followed by exhumation and cooling. The internal structure of the RMCC is characterized by the following succession of structure-forming events: (1) blueschist relics of Paleocene/Eocene age formed as a result of subduction (D1), (2) ductile nappe stacking (D2) of an ophiolite nappe over a distant passive margin succession (ca. E–W to WNW–ESE oriented stretching lineation), (3) greenschist facies-grade metamorphism annealing dominant in the lower unit, and (4) ductile low-angle normal faulting (D3) (with mainly NE–SW oriented stretching lineation), and (5) ca. E to NE-vergent folding (D4). The microfabrics are related to mostly ductile nappe stacking to ductile low-angle normal faulting. Paleopiezometry in conjunction with P–T estimates yield high strain rates of 10− 11 to 10− 13 s− 1, depending on the temperature (400–350 °C) and choice of piezometer and flow law calibration. Progressive microstructures and texture analysis indicate an overprint of the high-temperature fabrics (D2) by the low-temperature deformation (D3). Phengitic mica from the Paleocene/Eocene high-pressure metamorphism remained stable during D2 ductile deformation as well as preserved within late stages of final sub-greenschist facies shearing. Chlorite geothermometry yields two temperature groups, 376–328 °C, and 306–132 °C. Chlorite is seemingly accessible to late-stage resetting. The RMCC underwent an earlier large-scale coaxial

  11. Strain rate dependent calcite microfabric evolution - an experiment carried out by nature

    NASA Astrophysics Data System (ADS)

    Rogowitz, Anna; Grasemann, Bernhard; Rice, A. Hugh N.; Huet, Benjamin; Habler, Gerlinde

    2013-04-01

    The deformation behaviour of calcite has been studied experimentally in detail. Different strain rates and pressure and temperature conditions have been used to investigate a wide range of deformation regimes/mechanisms. However, a direct comparison with natural fault rocks remains difficult because of the extreme differences between experimental and natural strain rates. An a-type flanking structure developed in calcite-marbles of the Pyrgos unit, on Syros, provides a natural laboratory for directly studying the effects of strain rate variations at constant P-T conditions. The rocks of the Pyrgos unit underwent Eocene blueschist-facies metamorphism, resulting in coarse grained recrystallized marbles. During the subsequent greenschist-facies overprinting, the flanking structure started to form adjacent to a several meters long cross-cutting element (CE), which rotated into the shear direction, developing an antithetic offset. Comparing the microfabrics in the 1-2 cm thick CE mylonites and in the surrounding host rocks, which formed under the same metamorphic conditions but with different strain rates, is the central focus of this study. Numerical models have shown that a-type flanking folds form with a background shear strain of only about 1-2. However, the displacement along the CE varies between 60 and 120 cm, resulting in shear strains between 30 and 120. Assuming that all the deformation took place during the same event, significant strain rate variations (1 to 2 orders of magnitude) must have occurred between the CE and the host rock. Due to the extreme variations in strain and strain rate, different deformation mechanisms and types of dynamic recrystallization were active, leading to the development of different microstructures and textures. With increasing strain, the dominant deformation mechanism changed from twinning to dislocation glide and -climb and finally to diffusion creep. Additionally, a change from subgrain rotation to bulging recrystallization

  12. Comprehensive two-dimensional gas chromatographic separations with a temperature programmed microfabricated thermal modulator.

    PubMed

    Collin, William R; Nuñovero, Nicolas; Paul, Dibyadeep; Kurabayashi, Katsuo; Zellers, Edward T

    2016-04-29

    Comprehensive two-dimensional gas chromatography (GC×GC) with a temperature-programmed microfabricated thermal modulator (μTM) is demonstrated. The 0.78 cm(2), 2-stage μTM chip with integrated heaters and a PDMS coated microchannel was placed in thermal contact with a solid-state thermoelectric cooler and mounted on top of a bench scale GC. It was fluidically coupled through heated interconnects to an upstream first-dimension ((1)D) PDMS-coated capillary column and a downstream uncoated capillary or second-dimension ((2)D) PEG-coated capillary. A mixture of n-alkanes C6-C10 was separated isothermally and the full-width-at-half-maximum (fwhm) values of the modulated peaks were assessed as a function of the computer-controlled minimum and maximum stage temperatures of μTM, Tmin and Tmax, respectively. With Tmin and Tmax fixed at -25 and 100°C, respectively, modulated peaks of C6 and C7 had fwhm values<53 ms while the modulated peaks of C10 had a fwhm value of 1.3s, due to inefficient re-mobilization. With Tmin and Tmax fixed at 0 and 210°C, respectively, the fwhm value for the modulated C10 peaks decreased to 67 ms, but C6 and C7 exhibited massive breakthrough. By programming Tmin from -25 to 0°C and Tmax from 100 to 220°C, the C6 and C7 peaks had fwhm values≤50 ms, and the fwhm for C10 peaks remained<95 ms. Using the latter conditions for the GC×GC separation of a sample of unleaded gasoline yielded resolution similar to that reported with a commercial thermal modulator. Replacing the PDMS phase in the μTM with a trigonal-tricationic room temperature ionic liquid eliminated the bleed observed with the PDMS, but also reduced the capacity for several test compounds. Regardless, the demonstrated capability to independently temperature program this low resource μTM enhances its versatility and its promise for use in bench-scale GC×GC systems. PMID:27036209

  13. A microfabricated strain gauge array on polymer substrate for tactile neuroprostheses in rats

    NASA Astrophysics Data System (ADS)

    Beygi, M.; Mutlu, S.; Güçlü, B.

    2016-08-01

    In this study, we present the design, microfabrication and characterization of a tactile sensor system which can be used for sensory neuroprostheses in rats. The sensor system consists of an array of 2  ×  7 cells, each of which has a series combination of four strain gauges. Each group of four strain gauges is placed around a square membrane with a size of 2.5  ×  2.5 mm2. Unlike most common tactile sensors based on silicon substrates, we used 3D-printed polylactic acid as a substrate, because it is not brittle, and under local extremes, it would prevent the catastrophic failure of all cells. The strain gauges were fabricated by depositing and patterning a 50 nm thick aluminum (Al) film on a polyimide sheet with a thickness of 0.125 mm. Polydimethylsiloxane (PDMS) elastomer was bonded on the top surface of the PI membrane. The PDMS layer was prepared in two different thicknesses, 1.2 and 1.7 mm, to investigate its effect on the static response of the sensor. The sensitivity and the maximum allowable force, corresponding to the maximum deformation of 0.9 mm at the center of each cell, changed based on the thickness of the PDMS layer. Sensor cells operated linearly up to 3 N with an average sensitivity of 200 mΩ N‑1 (0.7 Ω mm‑1) for 1.2 mm thick PDMS. These values changed to 4 N and 70 mΩ N‑1 (0.3 Ω mm‑1), respectively, for 1.7 mm thick PDMS. The nonlinearity was less than 3%. The cells had low cross-talk (~5 mΩ N‑1 and 0.02 Ω mm‑1) relative to the average sensitivity. Additionally, the dynamic response of the sensor was characterized at several frequencies by using a vibrotactile stimulation system previously designed for psychophysics experiments. The sensor was also tested inside the rat conditioning chamber to demonstrate the relevant signals in a tactile neuroprosthesis.

  14. Microfabricated thermal conductivity sensor: a high resolution tool for quantitative thermal property measurement of biomaterials and solutions.

    PubMed

    Liang, Xin M; Ding, Weiping; Chen, Hsiu-hung; Shu, Zhiquan; Zhao, Gang; Zhang, Hai-feng; Gao, Dayong

    2011-10-01

    Obtaining accurate thermal properties of biomaterials plays an important role in the field of cryobiology. Currently, thermal needle, which is constructed by enclosing a manually winded thin metal wire with an insulation coating in a metallic sheath, is the only available device that is capable of measuring thermal conductivity of biomaterials. Major drawbacks, such as macroscale sensor size, lack of versatile format to accommodate samples with various shapes and sizes, neglected effects of heat transfer inside the probe and thermal contact resistance between the sensing element and the probe body, difficult to mass produce, poor data repeatability and reliability and labor-intense sensor calibration, have significantly reduced their potential to be an essential measurement tool to provide key thermal property information of biological specimens. In this study, we describe the development of an approach to measure thermal conductivity of liquids and soft bio-tissues using a proof-of-concept MEMS based thermal probe. By employing a microfabricated closely-packed gold wire to function as the heater and the thermistor, the presented thermal sensor can be used to measure thermal conductivities of fluids and natural soft biomaterials (particularly, the sensor may be directly inserted into soft tissues in living animal/plant bodies or into tissues isolated from the animal/plant bodies), where other more standard approaches cannot be used. Thermal standard materials have been used to calibrate two randomly selected thermal probes at room temperature. Variation between the obtained system calibration constants is less than 10%. By incorporating the previously obtained system calibration constant, three randomly selected thermal probes have been successfully utilized to measure the thermal conductivities of various solutions and tissue samples under different temperatures. Overall, the measurements are in agreement with the recommended values (percentage error less than 5

  15. Polyhalite microfabrics in an Alpine evaporite mélange: Hallstatt, Eastern Alps

    NASA Astrophysics Data System (ADS)

    Schorn, A.; Neubauer, F.; Bernroider, M.

    2012-04-01

    Polyhalite [K2Ca2Mg(SO4)4 . 2H2O] commonly occurs in sedimentary evaporite successions and was described first from the salt mine Bad Ischl-Perneck in Austria (province Upper Austria) and has since been known from many salt deposits (Warren, 2006; Springer-Verlag Berlin Heidelberg, 1035 p.). The study is undertaken for 40Ar/39Ar dating of tectonic processes of various polyhalite fabrics of Hallstatt, which have likely different formation ages, in order to supplement and extend further dating to further microfabric types as shown in Leitner (2011, Ph.D. thesis, University of Salzburg, 177 p.). In the Hallstatt salt mine, polyhalite rocks occur in 0.5 to 1 m thick tectonic lenses within the protocataclasite to protomylonite matrix of ductilely deformed halite of cataclastic clay-/mudstone. Thin section analysis of Hallstatt polyhalites reveal various fabric types including (1) polyhalite mylonites, (2) metamorphic reaction fabrics, (3) vein-filling, fibrous polyhalite and (4) cavity filling polyhalite. The polyhalite mylonites most likely formed along shear zones at high strain rates due to intracrystalline deformation and recrystallization. They may have developed from a more coarse-grained precursor metamorphic rock. Texture measurements by the electron back-scattered diffraction technique are in progress. The mylonites show a wide range of shear fabrics commonly known in mylonitic shear zones of the ductile crust. The mylonites are partly overprinted by recrystallized polyhalite grains, which are probably indicating a static growth. Metamorphic reaction fabrics of blödite (or astrakanite) [Na2Mg(SO4)2 . 4 H2O] between polyhalite seams and anhydrite has been found, too. According to Schauberger (1986, Archiv für Lagerstättenforschung der Geologischen Bundesanstalt, v. 7, p. 217-254), blödite of the Alpine Haselgebirge may occur primary as nodules or, more common, intergrown with the mineral löweite, which has a nearly identical chemical composition and is

  16. Sensitive Amino Acid Composition and Chirality Analysis in the Martian Regolith with a Microfabricated in situ Analyzer

    NASA Astrophysics Data System (ADS)

    Skelley, A. M.; Grunthaner, F. J.; Bada, J. L.; Mathies, R. A.

    2003-12-01

    Recent advances in microfabricated "lab-on-a-chip" technologies have dramatically enhanced the capabilities of chemical and biochemical analyzers. The portability and sensitivity of these devices makes them ideal instruments for in situ chemical analysis on other planets. We have focused our initial studies on amino acid analysis because amino acids are more chemically resistant to decomposition than other biomolecules, and because amino acid chirality is a well-defined biomarker [1]. Previously, we developed a prototype electrophoresis chip, detection system and analysis method where the amino acids were labeled with fluorescein using FITC and then electrophoretically analyzed using g-cyclodextrin as the chiral resolution agent [2]. Extracts of the Murchison meteorite were analyzed, and the D/L ratios determined by microchip CE closely matched those from HPLC and GCMS and exhibited greater precision. Our microchip analyzer has now been further improved by establishing the capability of performing amino acid composition and chirality analyses using fluorescamine rather than FITC [3]. Fluorescamine is advantageous because it reacts more rapidly than FITC, and because excess reagent is hydrolyzed to a non-fluorescent product. Furthermore, the use of fluorescamine facilitates interfacing with the Mars Organic Detector (MOD) [4]. Fluorescamine-amino acids are separated using similar conditions as the FITC-aa, resulting in similar separation times and identical elution orders. Fluorescamine-aa are chirally resolved in the presence of hydroxy-propyl-b-cyclodextrin, and typical limits of detection are ˜ 50 nM. This work establishes the feasibility of combining fluorescamine labeling of amino acids with microfabricated CE devices to develop low-volume, high-sensitivity apparatus for extraterrestrial exploration. The stage is now set for the development of the Mars Organic Analyzer (MOA), a portable analysis system for amino acid extraction and chiral analysis that will

  17. A Micro-fabricated Hydrogen Storage Module with Sub-atmospheric Activation and Durability in Air Exposure.

    PubMed

    Shan, Xi; Payer, Joe H; Wainright, Jesse S; Dudik, Laurie

    2011-01-15

    The objective of this work was to develop a hydrogen storage module for onboard electrical power sources suitable for use in micro power systems and micro-electro-mechanical systems (MEMS). Hydrogen storage materials were developed as thin-film inks to be compatible with an integrated manufacturing process. Important design aspects were (a) ready activation at sub-atmospheric hydrogen pressure and room temperature and (b) durability, i.e. capable of hundreds of absorption/desorption cycles and resistance to deactivation on exposure to air. Inks with palladium-treated intermetallic hydrogen storage alloys were developed and are shown here to be compatible with a thin-film micro-fabrication process. These hydrogen storage modules absorb hydrogen readily at atmospheric pressure, and the absorption/desorption rates remained fast even after the ink was exposed to air for 47 weeks. PMID:20967132

  18. Microfabricated microengine for use as a mechanical drive and power source in the microdomain and fabrication process

    DOEpatents

    Garcia, Ernest J.; Sniegowski, Jeffry J.

    1997-01-01

    A microengine uses two synchronized linear actuators as a power source and converts oscillatory motion from the actuators into rotational motion via direct linkage connection to an output gear or wheel. The microengine provides output in the form of a continuously rotating output gear that is capable of delivering drive torque to a micromechanism. The microengine can be operated at varying speeds and its motion can be reversed. Linear actuators are synchronized in order to provide linear oscillatory motion to the linkage means in the X and Y directions according to a desired position, rotational direction and speed of said mechanical output means. The output gear has gear teeth on its outer perimeter for directly contacting a micromechanism requiring mechanical power. The gear is retained by a retaining means which allows said gear to rotate freely. The microengine is microfabricated of polysilicon on one wafer using surface micromachining batch fabrication.

  19. Microfabricated microengine for use as a mechanical drive and power source in the microdomain and fabrication process

    DOEpatents

    Garcia, E.J.; Sniegowski, J.J.

    1997-05-20

    A microengine uses two synchronized linear actuators as a power source and converts oscillatory motion from the actuators into rotational motion via direct linkage connection to an output gear or wheel. The microengine provides output in the form of a continuously rotating output gear that is capable of delivering drive torque to a micromechanism. The microengine can be operated at varying speeds and its motion can be reversed. Linear actuators are synchronized in order to provide linear oscillatory motion to the linkage means in the X and Y directions according to a desired position, rotational direction and speed of said mechanical output means. The output gear has gear teeth on its outer perimeter for directly contacting a micromechanism requiring mechanical power. The gear is retained by a retaining means which allows said gear to rotate freely. The microengine is microfabricated of polysilicon on one wafer using surface micromachining batch fabrication. 30 figs.

  20. A Micro-fabricated Hydrogen Storage Module with Sub-atmospheric Activation and Durability in Air Exposure

    PubMed Central

    Shan, Xi; Payer, Joe H.; Wainright, Jesse S; Dudik, Laurie

    2010-01-01

    The objective of this work was to develop a hydrogen storage module for onboard electrical power sources suitable for use in micro power systems and micro-electro-mechanical systems (MEMS). Hydrogen storage materials were developed as thin-film inks to be compatible with an integrated manufacturing process. Important design aspects were (a) ready activation at sub-atmospheric hydrogen pressure and room temperature and (b) durability, i.e. capable of hundreds of absorption/desorption cycles and resistance to deactivation on exposure to air. Inks with palladium-treated intermetallic hydrogen storage alloys were developed and are shown here to be compatible with a thin-film micro-fabrication process. These hydrogen storage modules absorb hydrogen readily at atmospheric pressure, and the absorption/desorption rates remained fast even after the ink was exposed to air for 47 weeks. PMID:20967132

  1. Microfabrication of controlled-geometry samples for the laser-heated diamond-anvil cell using focused ion beam technology

    SciTech Connect

    Pigott, Jeffrey S.; Reaman, Daniel M.; Panero, Wendy R.

    2012-02-06

    The pioneering of x-ray diffraction with in situ laser heating in the diamond-anvil cell has revolutionized the field of high-pressure mineral physics, expanding the ability to determine high-pressure, high-temperature phase boundaries and equations of state. Accurate determination of high-pressure, high-temperature phases and densities in the diamond-anvil cell rely upon collinearity of the x-ray beam with the center of the laser-heated spot. We present the development of microfabricated samples that, by nature of their design, will have the sample of interest in the hottest portion of the sample. We report initial successes with a simplified design using a Pt sample with dimensions smaller than the synchrotron-based x-ray spot such that it is the only part of the sample that absorbs the heating laser ensuring that the x-rayed volume is at the peak hotspot temperature. Microfabricated samples, synthesized using methods developed at The Ohio State University's Mineral Physics Laboratory and Campus Electron Optics Facility, were tested at high P-T conditions in the laser-heated diamond-anvil cell at beamline 16 ID-B of the Advanced Photon Source. Pt layer thicknesses of {le} 0.8 {micro}m absorb the laser and produce accurate measurements on the relative equations of state of Pt and PtC. These methods combined with high-purity nanofabrication techniques will allow for extension by the diamond-anvil cell community to multiple materials for high-precision high-pressure, high-temperature phase relations, equations of state, melting curves, and transport properties.

  2. Guided and magnetic self-assembly of tunable magnetoceptive gels

    NASA Astrophysics Data System (ADS)

    Tasoglu, S.; Yu, C. H.; Gungordu, H. I.; Guven, S.; Vural, T.; Demirci, U.

    2014-09-01

    Self-assembly of components into complex functional patterns at microscale is common in nature, and used increasingly in numerous disciplines such as optoelectronics, microfabrication, sensors, tissue engineering and computation. Here, we describe the use of stable radicals to guide the self-assembly of magnetically tunable gels, which we call ‘magnetoceptive’ materials at the scale of hundreds of microns to a millimeter, each can be programmed by shape and composition, into heterogeneous complex structures. Using paramagnetism of free radicals as a driving mechanism, complex heterogeneous structures are built in the magnetic field generated by permanent magnets. The overall magnetic signature of final structure is erased via an antioxidant vitamin E, subsequent to guided self-assembly. We demonstrate unique capabilities of radicals and antioxidants in fabrication of soft systems with heterogeneity in material properties, such as porosity, elastic modulus and mass density; then in bottom-up tissue engineering and finally, levitational and selective assembly of microcomponents.

  3. Guided and magnetic self-assembly of tunable magnetoceptive gels

    PubMed Central

    Tasoglu, S.; Yu, C.H.; Gungordu, H.I.; Guven, S.; Vural, T.; Demirci, U.

    2014-01-01

    Self-assembly of components into complex functional patterns at microscale is common in nature, and used increasingly in numerous disciplines such as optoelectronics, microfabrication, sensors, tissue engineering and computation. Here, we describe the use of stable radicals to guide the self-assembly of magnetically tunable gels, which we call ‘magnetoceptive’ materials at the scale of hundreds of microns to a millimeter, each can be programmed by shape and composition, into heterogeneous complex structures. Using paramagnetism of free radicals as a driving mechanism, complex heterogeneous structures are built in the magnetic field generated by permanent magnets. The overall magnetic signature of final structure is erased via an antioxidant vitamin E, subsequent to guided self-assembly. We demonstrate unique capabilities of radicals and antioxidants in fabrication of soft systems with heterogeneity in material properties, such as porosity, elastic modulus and mass density; then in bottom-up tissue engineering and finally, levitational and selective assembly of microcomponents. PMID:25175148

  4. Magnetic quadrupole doublet focusing system for high energy ions.

    PubMed

    Glass, Gary A; Dymnikov, Alexander D; Rout, Bibhudutta; Dias, Johnny F; Houston, Louis M; LeBlanc, Jared

    2008-03-01

    A high energy focused ion beam microprobe using a doublet arrangement of short magnetic quadrupole lenses was used to focus 1-3 MeV protons to spot sizes of 1x1 microm2 and 1-4.5 MeV carbon and silicon ion beams to spot sizes of 1.5x1.5 microm2. The results presented clearly demonstrate that this simple doublet configuration can provide high energy microbeams for microanalysis and microfabrication applications. PMID:18377047

  5. Rapid enrichment of leucocytes and genomic DNA from blood based on bifunctional core shell magnetic nanoparticles

    NASA Astrophysics Data System (ADS)

    Xie, Xin; Nie, Xiaorong; Yu, Bingbin; Zhang, Xu

    2007-04-01

    A series of protocols are proposed to extract genomic DNA from whole blood at different scales using carboxyl-functionalized magnetic nanoparticles as solid-phase absorbents. The enrichment of leucocytes and the adsorption of genomic DNA can be achieved with the same carboxyl-functionalized magnetic nanoparticles. The DNA bound to the bead surfaces can be used directly as PCR templates. By coupling cell separation and DNA purification, the whole operation can be accomplished in a few minutes. Our simplified protocols proved to be rapid, low cost, and biologically and chemically non-hazardous, and are therefore promising for microfabrication of a DNA-preparation chip and routine laboratory use.

  6. A Microfabricated Segmented-Involute-Foil Regenerator for Enhancing Reliability and Performance of Stirling Engines. Phase III Final Report for the Radioisotope Power Conversion Technology NRA

    NASA Technical Reports Server (NTRS)

    Ibrahim, Mounir B.; Gedeon, David; Wood, Gary; McLean, Jeffrey

    2009-01-01

    Under Phase III of NASA Research Announcement contract NAS3-03124, a prototype nickel segmented-involute-foil regenerator was microfabricated and tested in a Sunpower Frequency-Test-Bed (FTB) Stirling convertor. The team for this effort consisted of Cleveland State University, Gedeon Associates, Sunpower Inc. and International Mezzo Technologies. Testing in the FTB convertor produced about the same efficiency as testing with the original random-fiber regenerator. But the high thermal conductivity of the prototype nickel regenerator was responsible for a significant performance degradation. An efficiency improvement (by a 1.04 factor, according to computer predictions) could have been achieved if the regenerator was made from a low-conductivity material. Also, the FTB convertor was not reoptimized to take full advantage of the microfabricated regenerator s low flow resistance; thus, the efficiency would likely have been even higher had the FTB been completely reoptimized. This report discusses the regenerator microfabrication process, testing of the regenerator in the Stirling FTB convertor, and the supporting analysis. Results of the pre-test computational fluid dynamics (CFD) modeling of the effects of the regenerator-test-configuration diffusers (located at each end of the regenerator) are included. The report also includes recommendations for further development of involute-foil regenerators from a higher-temperature material than nickel.

  7. Polyphase serpentinization history of Mariana forearc mantle: observations on the microfabric of ultramafic clasts from ODP Leg 195, Site 1200

    NASA Astrophysics Data System (ADS)

    Kahl, Wolf-Achim; Jöns, Niels; Bach, Wolfgang; Klein, Frieder

    2013-04-01

    In the forearc of the Mariana subduction zone system, a number of seamounts form from extrusion of blueschist and serpentine mud. Ocean Drilling Program Leg 195 drilled the South Chamorro seamount, where ultramafic clasts occur within the mud matrix. These clasts show a complex serpentinization history, which bears the potential for tracking the alteration history during uplift and cooling of mantle wedge rocks to the seafloor. Moreover, the microfabrics of the highly serpentinized harzburgite and dunite clasts exhibit evidence for multiple fracturing events in the forearc mantle. These, in turn, lead to fluid influx and varied styles of serpentinization of harzburgite and dunite. The serpentinized ultramafic clasts exhibit a variety of microfabrics that range from virtually undeformed to strongly deformed samples. Pervasively serpentinized harzburgites feature either an equigranular fabric of serpentinized olivine and orthopyroxene crystals, or different vein generations related to multiple stages of serpentinization. Several types of fluid pathways in harzburgites are present: (i) veins containing brucite and iron oxides, developed linearly without marked conformance with the rock fabric. In places, these veins developed mm-cm wide halos with finger-shaped serpentinization fronts. Veins of type (i) are either developed as syntaxial veins from a single crack-seal event with large magnetite crystals growing from one wall to the other (as confirmed with high-resolution X-ray microtomography), or formed by multiple fluid events. (ii) serpentine veins that encompass regions of marginally serpentinized, microgranular olivine and large orthopyroxene crystals. (iii) extensional serpentine veins (known as "Frankenstein" type). In the clasts studied, their occurrence is restricted to the halo region of type (i) veins. (iv) as a late-stage feature, extensional veins documenting multiple crack-seal events can be present in the serpentinites (either in undeformed regions with

  8. Deformation and Brittle Failure of Folded Gneiss in Triaxial Compression: Failure Modes, Acoustic Signatures and Microfabric Controls

    NASA Astrophysics Data System (ADS)

    Agliardi, F.; Vinciguerra, S.; Dobbs, M. R.; Zanchetta, S.

    2014-12-01

    Fabric anisotropy is a key control of rock behavior in different geological settings and over different timescales. However, the effect of tectonically folded fabrics on the brittle strength and failure mode of metamorphic rocks is poorly understood. Recent data, obtained from uniaxial compression experiments on folded gneiss (Agliardi et al., 2014), demonstrated that their brittle failure modes depend upon the arrangement of two anisotropies (i.e. foliation and fold axial planes) and that rock strength correlates with failure mode. Since lithostatic pressure may significantly affect this rock behavior, we investigated its effect in triaxial compression experiments. We tested the Monte Canale Gneiss (Italian Alps), characterized by low phyllosilicate content and compositional layering folded at the cm-scale. We used a servo-controlled hydraulic loading system to test 19 air-dry cylindrical specimens (ø = 54 mm) that were characterized both in terms of fold geometry and orientation of foliation and fold axial planes to the axial load direction. The specimens were instrumented with direct contact axial and circumferential strain gauges. Acoustic emissions and P- and S-wave velocities were measured by piezoelectric transducers mounted in the compression platens. The tests were performed at confining pressures of 40 MPa and axial strain rates of 5*10-6 s-1. Post-failure study of fracture mechanisms and related microfabric controls was undertaken using X-ray CT, optical microscopy and SEM. Samples failed in three distinct brittle modes produced by different combinations of fractures parallel to foliation, fractures parallel to fold axial planes, or mm-scale shear bands. The failure modes, consistent with those described in uniaxial compression experiments, were found to be associated with distinct stress-strain and acoustic emission signatures. Failure modes involving quartz-dominated axial plane anisotropy correspond to higher peak strength and axial strain, less

  9. Microfabricated refractive index gradient based detector for reversed-phase liquid chromatography with mobile phase gradient elution.

    PubMed

    McBrady, Adam D; Synovec, Robert E

    2006-02-10

    Typical refractive index (RI) detectors for liquid chromatography (LC) are not well suited to application with mobile phase gradient elution, due to the difficulty in correcting for the detected baseline shift during the gradient. We report a sensitive, highly reproducible, microfabricated refractive index gradient (micro-RIG) detector that performs well with mobile phase gradient elution LC. Since the micro-RIG signal remains on-scale throughout the mobile phase gradient, one can apply a baseline correction procedure. We demonstrate that by collecting two mobile phase gradient blanks and subtracting one of them from the other, a reproducible, flat baseline is achieved. Therefore, subtracting a blank from a separation provides a baseline corrected chromatogram with reasonably high signal-to-noise ratio for eluting analytes. The micro-RIG detector uses a collimated diode laser beam to optically probe a RIG formed perpendicular to the laminar flow direction within a microfabricated borosilicate glass chip. The chip-based design of the detector is suitable for either traditional bench-top or LC-on-a-chip technologies. We report reversed phase high performance liquid chromatography (RP-HPLC) separations of proteins and polymers, over mobile phase gradient conditions of 67% A:33% B to 3% A:97% B by volume, where A is 96% methanol:3.9% water:0.1% trifluoroacetic acid (TFA), and B is 3.9% methanol:96% water:0.1% TFA. The separations were performed on a Jupiter 5 mu C4 300 A 150 mm x 1.0 mm Phenomenex column at a flow rate of 20 microl/min. Viscosity changes during the mobile phase gradient separation are found to shift the on-chip merge position of the detected concentration gradient (i.e., RIG), in a reproducible fashion. However, this viscosity effect makes detection sensitivity vary throughout the mobile phase gradient, due to moving the optimized position of the probe beam in relation to the analyte concentration gradient being probed. None-the-less, consistent limits

  10. High accuracy thermal conductivity measurement of aqueous cryoprotective agents and semi-rigid biological tissues using a microfabricated thermal sensor

    PubMed Central

    Liang, Xin M.; Sekar, Praveen K.; Zhao, Gang; Zhou, Xiaoming; Shu, Zhiquan; Huang, Zhongping; Ding, Weiping; Zhang, Qingchuan; Gao, Dayong

    2015-01-01

    An improved thermal-needle approach for accurate and fast measurement of thermal conductivity of aqueous and soft biomaterials was developed using microfabricated thermal conductivity sensors. This microscopic measuring device was comprehensively characterized at temperatures from 0 °C to 40 °C. Despite the previous belief, system calibration constant was observed to be highly temperature-dependent. Dynamic thermal conductivity response during cooling (40 °C to –40 °C) was observed using the miniaturized single tip sensor for various concentrations of CPAs, i.e., glycerol, ethylene glycol and dimethyl sulfoxide. Chicken breast, chicken skin, porcine limb, and bovine liver were assayed to investigate the effect of anatomical heterogeneity on thermal conductivity using the arrayed multi-tip sensor at 20 °C. Experimental results revealed distinctive differences in localized thermal conductivity, which suggests the use of approximated or constant property values is expected to bring about results with largely inflated uncertainties when investigating bio-heat transfer mechanisms and/or performing sophisticated thermal modeling with complex biological tissues. Overall, the presented micro thermal sensor with automated data analysis algorithm is a promising approach for direct thermal conductivity measurement of aqueous solutions and soft biomaterials and is of great value to cryopreservation of tissues, hyperthermia or cryogenic, and other thermal-based clinical diagnostics and treatments. PMID:25993037

  11. Development of a microfabricated disposable microchip with a capillary electrophoresis and integrated three-electrode electrochemical detection.

    PubMed

    Kim, Ju-Ho; Kang, C J; Kim, Yong-Sang

    2005-05-15

    We have developed microsystems with a capillary electrophoresis and an electrochemical detector. The microfabricated CE-ECD systems are adequate for a disposable type and the characteristics are optimized for application in electrochemical detection. The system was realized by means of a polydimethylsiloxane (PDMS)-glass chip and an indium tin oxide electrode. The injection and separation channels were produced by relatively simple and inexpensive methods. A capillary electrophoresis and a three-electrode electrochemical detector were fabricated on the same substrate with the same fabrication procedure. We measured electropherograms for the testing analytes consisting of catechol and dopamine with different concentrations of 1mM and 0.1mM, respectively. The results showed an efficient and rapid separation and detection of all compounds within a very short time of around 80s using a separate electric field 60 V/cm. We could also successfully achieve an electropherogram of the separation of the 1 kb DNA ladder (8.4 ng/mul) from the 500 bp to 10 kb DNA fragments within just 150 s. PMID:15797332

  12. High accuracy thermal conductivity measurement of aqueous cryoprotective agents and semi-rigid biological tissues using a microfabricated thermal sensor

    NASA Astrophysics Data System (ADS)

    Liang, Xin M.; Sekar, Praveen K.; Zhao, Gang; Zhou, Xiaoming; Shu, Zhiquan; Huang, Zhongping; Ding, Weiping; Zhang, Qingchuan; Gao, Dayong

    2015-05-01

    An improved thermal-needle approach for accurate and fast measurement of thermal conductivity of aqueous and soft biomaterials was developed using microfabricated thermal conductivity sensors. This microscopic measuring device was comprehensively characterized at temperatures from 0 °C to 40 °C. Despite the previous belief, system calibration constant was observed to be highly temperature-dependent. Dynamic thermal conductivity response during cooling (40 °C to -40 °C) was observed using the miniaturized single tip sensor for various concentrations of CPAs, i.e., glycerol, ethylene glycol and dimethyl sulfoxide. Chicken breast, chicken skin, porcine limb, and bovine liver were assayed to investigate the effect of anatomical heterogeneity on thermal conductivity using the arrayed multi-tip sensor at 20 °C. Experimental results revealed distinctive differences in localized thermal conductivity, which suggests the use of approximated or constant property values is expected to bring about results with largely inflated uncertainties when investigating bio-heat transfer mechanisms and/or performing sophisticated thermal modeling with complex biological tissues. Overall, the presented micro thermal sensor with automated data analysis algorithm is a promising approach for direct thermal conductivity measurement of aqueous solutions and soft biomaterials and is of great value to cryopreservation of tissues, hyperthermia or cryogenic, and other thermal-based clinical diagnostics and treatments.

  13. Rheological (visco-elastic behaviour) analysis of cyclic olefin copolymers with application to hot embossing for microfabrication

    NASA Astrophysics Data System (ADS)

    Jena, R. K.; Chen, X.; Yue, C. Y.; Lam, Y. C.

    2011-08-01

    Transparent, amorphous cyclic olefin copolymers (COCs) have been frequently used for the fabrication of microfluidic devices using a hot embossing technique for numerous applications. In hot embossing, the polymer is deformed near its glass transition temperature (Tg), i.e. between Tg and Tg + 60 °C where the viscoelastic properties of the material are dominant. The proper characterization of the viscoelastic properties is of interest as this can lead to a better understanding of polymer flow behaviour during microfabrication. Furthermore, the ability to model its rheological behaviour will enable the prediction of the optimal hot embossing processing parameters. We performed small amplitude oscillatory shear experiments on four grades of COCs, TOPAS-8007, TOPAS-5013, TOPAS-6015 and TOPAS-6017, in order to characterize their flow behaviour. The experiments were conducted within the frequency range from 0.01 to 500 Hz at between Tg + 20 and Tg + 60 °C. The flow properties could be represented using a generalized Maxwell viscoelastic constitutive model with Williams-Landel-Ferry-type temperature dependence. Good fit of the experimental data was obtained over a wide range of temperatures. The model could be coupled with ABAQUS finite element software to predict the optimal conditions for fabricating a capillary electrophoresis micro-chip on a TOPAS-5013 substrate by hot embossing.

  14. Real three-dimensional microfabrication for biodegradable polymers: demonstration of high-resolution and biocompatibility for implantable microdevices.

    PubMed

    Ikuta, Koji; Yamada, Akira; Niikura, Fuminori

    2004-01-01

    We have developed a novel three-dimensional (3D) microfabrication method for biodegradable polymers. Unlike conventional processes, our process satisfies high-resolution and high-speed requirements. The system design allows us the processing of microlevel forms by stacking up melted polymers from the nozzle. We adopted a batch process to supply materials in order to eliminate the prior process that required toxic solvents. In addition, it is possible to handle almost all biodegradable thermoplastic resins by adopting this system. A single layer from the piled-up layers of extruded lines was observed to evaluate the resolution. The lateral and depth resolutions attained are 40 mum and 45 mum, respectively. Biodegradable polymers enable three-dimensional microstructures such as micropipes, microbends, and microcoil springs to be manufactured in less than 15 min. The biocompatibility of the newly fabricated structure was evaluated using a cell line (PC12). For this purpose, a small vessel, with a transparent base, was fabricated using PLA and cells were cultivated in it. The results were then compared with the results obtained using the standard method. Our system renders it possible to produce toxic-free, as well as transparent and leakage-free devices. Our system is expected to have potential applications in optimum design and fabrication of implantable devices, especially in tissue engineering. PMID:17270828

  15. Human mammalian cell sorting using a highly integrated micro-fabricated fluorescence-activated cell sorter (μFACS)

    PubMed Central

    Cho, Sung Hwan; Chen, Chun H.; Tsai, Frank S.; Godin, Jessica M.; Lo, Yu-Hwa

    2011-01-01

    We demonstrate a high performance microfabricated FACS system with highly integrated microfluidics, optics, acoustics, and electronics. Single cell manipulation at a high speed is made possible by the fast response time (~0.1 ms) of the integrated PZT actuator and the nozzle structure at the sorting junction. A Teflon AF-coated optofluidic waveguide along the microfluidic channel guides the illumination light, enabling multi-spot detection, while a novel space-time coding technology enhances the detection sensitivity of the μFACS system. The real-time control loop system is implemented using a field-programmable-gate-array (FPGA) for automated and accurate sorting. The μFACS achieves a high purification enrichment factor: up to ~230 fold for both polystyrene microbeads and suspended human mammalian cells (K562) at a high throughput (>1000 cells s−1). The sorting mechanism is independent of cell properties such as size, density, and shape, thus the presented system can be applied to sort out any pure sub-populations. This new lab-on-a-chip FACS system, therefore, holds promise to revolutionize microfluidic cytometers to meet cost, size, and performance goals. PMID:20379604

  16. Dense type I collagen matrices that support cellular remodeling and microfabrication for studies of tumor angiogenesis and vasculogenesis in vitro

    PubMed Central

    Cross, Valerie L.; Zheng, Ying; Choi, Nak Won; Verbridge, Scott S.; Sutermaster, Bryan A.; Bonassar, Lawrence J.; Fischbach, Claudia; Stroock, Abraham D.

    2010-01-01

    Type I collagen is a favorable substrate for cell adhesion and growth and is remodelable by many tissue cells; these characteristics make it an attractive material for the study of dynamic cellular processes. Low mass fraction (1.0–3.0 mg/ml), hydrated collagen matrices used for three-dimensional cell culture permit cellular movement and remodeling, but their microstructure and mechanics fail to mimic characteristics of many extracellular matrices in vivo and limit the definition of fine-scale geometrical features (< 1 mm) within scaffolds. In this study, we worked with hydrated type I collagen at mass fractions between 3.0 and 20 mg/ml to define the range of densities over which the matrices support both microfabrication and cellular remodeling. We present pore and fiber dimensions based on confocal microscopy and longitudinal modulus and hydraulic permeability based on confined compression. We demonstrate faithful reproduction of simple pores of 50 µm-diameter over the entire range and formation of functional microfluidic networks for mass fractions greater than 10.0 mg/ml. We present quantitative characterization of the rate and extent of cellular remodelability using human umbilical vein endothelial cells. Finally, we present a co-culture with tumor cells and discuss the implications of integrating microfluidic control within scaffolds as a tool to study spatial and temporal signaling during tumor angiogenesis and vascularization of tissue-engineered constructs. PMID:20727585

  17. Microfabrication and Device Parameter Testing of the Focal Plane Arrays for the Spider and BICEP2/Keck CMB Polarimeters

    NASA Astrophysics Data System (ADS)

    Bonetti, J. A.; Turner, A. D.; Kenyon, M.; Orlando, A.; Brevik, J. A.; Trangsrud, A.; Sudiwala, R.; Leduc, H. G.; Nguyen, H. T.; Day, P. K.; Bock, J. J.; Golwala, S. R.; Sayers, J.; Kovac, J. M.; Lange, A. E.; Jones, W. C.; Kuo, C. L.

    2009-12-01

    Spider and BICEP2/Keck are projects to study the polarization of the cosmic microwave background (CMB). The focal planes for both require large format arrays of superconducting transition edge sensors (TES's). A major challenge for these projects is fabricating arrays with high uniformity in device parameters. A microfabrication process is described that meets this challenge. The results from device testing are discussed. Each focal plane is composed of 4 square wafers (tiles), and each wafer contains 128 membrane-isolated, polarization-sensitive, antenna-coupled TES's. After processing, selected wafers are pre-screened in a quick-turn-around, cryogen-free, 3He fridge. The pre-screening is performed with a commercial resistance bridge and measures transition temperatures (Tc) and normal state resistances (Rn). After pre-screening, 4 tiles at a time are fully characterized in a testbed employing a SQUID readout and SQUID mulitplexing. The tests demonstrate the values of Tc, Rn, thermal conductance, g, and the standard deviations of each, across a wafer and from wafer to wafer, are within design specifications.

  18. In situ conditions and interactions between microbes and minerals in fine-grained marine sediments: A TEM microfabric perspective

    SciTech Connect

    Ransom, B.; Bennett, R.H.; Baerwald, R.; Hulbert, M.H.; Burkett, P.J.

    1999-01-01

    Microbes, their exocellular secretions, and their impact on the mineralogy and microfabric of fine-grained continental margin sediments were investigated by transmission electron microscopy. Techniques were used that retained the in situ spatial relations of both bio-organic and mineralogical constituents. Photomicrographs were taken of characteristic mineral-microbe associations in the first meter of burial at conditions ranging from aerobic to anaerobic. Single-celled prokaryotes, prokaryotic colonies, and eukaryotic organisms were observed as were motile, sessile, and predatory species. Bacterial cells dominate the assemblage. The most commonly observed mineral-biological interaction was the surrounding, or close association, of isolated heterotrophic bacterial cells by clay minerals. Almost without exception, the external surfaces of the bacteria were covered with secreted exocellular slimes composed of cross-linked polysaccharide fibrils. These fibrils act to bind sediment grains into relatively robust microaggregates, roughly {le} 25 {micro}m in diameter. These exocellular polymers can significantly impact the interaction between microbes and minerals, as well as the chemical and physical transport of fluids and dissolved aqueous species through the sediment. Although pore water chemical profiles from the field sites studied have dissolved Fe and Mn, no close association was found between the microbes imaged and precipitated metal oxyhydroxides or other authigenic minerals, such as is commonly reported from laboratory cultures.

  19. Design and implementation of injector/distributor structures for microfabricated non-porous pillar columns for capillary electrochromatography.

    PubMed

    Sukas, Sertan; Desmet, Gert; Gardeniers, Han J G E

    2013-05-10

    A previously proposed foil definition is applied in the design of injector/distributor structures for solid microfabricated column structures for capillary electrochromatography. In addition to a typical bifurcated distributor, an optimized design alternative with two different configurations is experimentally evaluated. Optimized designs yielded a flat profile for the injected sample with a maximum of 3% variation from the mean width, while it went up to 18% for the typical bifurcated distributor. The implemented electrokinetic injection approach enabled controlling the volume of the injected sample accurately without sacrificing the compactness of the device design. The width of the injected sample was directly proportional to the injection time, namely 165 and 218 μm base widths were obtained for 0.6 and 0.8s of feeding, respectively. Reducing the external porosity of the distributor by 85% compared to the typical design, optimized distributors caused a decrease in the mean flow velocity of up to 70%. However, having a flat initial plug shape enabled the separation of a mixture of Coumarin 440, 460, 480 and 540 at 1 mm downstream of the injection point in 80s, while it was even not possible to detect the C440 signal for a typical bifurcated design. PMID:23561733

  20. Microscopically-Tuned Band Structure of Epitaxial Graphene through Interface and Stacking Variations Using Si Substrate Microfabrication

    PubMed Central

    Fukidome, Hirokazu; Ide, Takayuki; Kawai, Yusuke; Shinohara, Toshihiro; Nagamura, Naoka; Horiba, Koji; Kotsugi, Masato; Ohkochi, Takuo; Kinoshita, Toyohiko; Kumighashira, Hiroshi; Oshima, Masaharu; Suemitsu, Maki

    2014-01-01

    Graphene exhibits unusual electronic properties, caused by a linear band structure near the Dirac point. This band structure is determined by the stacking sequence in graphene multilayers. Here we present a novel method of microscopically controlling the band structure. This is achieved by epitaxy of graphene on 3C-SiC(111) and 3C-SiC(100) thin films grown on a 3D microfabricated Si(100) substrate (3D-GOS (graphene on silicon)) by anisotropic etching, which produces Si(111) microfacets as well as major Si(100) microterraces. We show that tuning of the interface between the graphene and the 3C-SiC microfacets enables microscopic control of stacking and ultimately of the band structure of 3D-GOS, which is typified by the selective emergence of semiconducting and metallic behaviours on the (111) and (100) portions, respectively. The use of 3D-GOS is thus effective in microscopically unlocking various potentials of graphene depending on the application target, such as electronic or photonic devices. PMID:24903119

  1. A compact UHV package for microfabricated ion-trap arrays with direct electronic air-side access

    NASA Astrophysics Data System (ADS)

    Wilpers, Guido; See, Patrick; Gill, Patrick; Sinclair, Alastair G.

    2013-04-01

    We have demonstrated a new apparatus for operating microfabricated ion-trap arrays in a compact ultra-high-vacuum setup with excellent optical and electrical access. The approach uses conventional components, materials and techniques in a unique fashion. The microtrap chip is mounted on a modified ceramic leadless chip carrier, the conductors of which serve as the vacuum feedthrough. The chip carrier is indium-sealed to stainless-steel components to form vacuum seals, resulting in short electrical path lengths of ≤20 mm from the trap electrodes under vacuum to air side. The feedthrough contains conductors for the radio-frequency trap drive, as well as 42 conductors for DC electrodes. Vacuum pressures of ˜1 × 10-11 mbar are achieved, and ions have been confined and laser cooled in a microtrap chip. The apparatus enables accurate measurements of radio-frequency voltage amplitudes on the trap electrodes, yielding an excellent agreement between measured and modelled trap efficiencies. This feature is of significant use in establishing initial operation of new devices. The principle of the connectivity scheme presented here is applicable to larger ceramic chip carriers containing many more conductors.

  2. Microfabrics and 3D grain shape of Gorleben rock salt: Constraints on deformation mechanisms and paleodifferential stress

    NASA Astrophysics Data System (ADS)

    Thiemeyer, Nicolas; Zulauf, Gernold; Mertineit, Michael; Linckens, Jolien; Pusch, Maximilian; Hammer, Jörg

    2016-04-01

    The Permian Knäuel- and Streifensalz formations (z2HS1 and z2HS2) are main constituents of the Gorleben salt dome (Northern Germany) and show different amounts and distributions of anhydrite. The reconstruction of 3D halite grain shape ellipsoids reveals small grain size (3.4 ± 0.6 mm) and heterogeneous grain shapes in both formations, the latter attributed to the polyphase deformation of the rock salt during diapirism. The halite microfabrics of both formations indicate that strain-induced grain boundary migration was active during deformation. Crystal plastic deformation of halite is further documented by lattice bending, subgrain formation and minor subgrain rotation. Evidence for pressure solution of halite has not been found, but cannot be excluded because of the small grain size, the lack of LPO and the low differential stress (1.1-1.3 MPa) as deduced from subgrain-size piezometry. Anhydrite has been deformed in the brittle-ductile regime by solution precipitation creep, minor dislocation creep and brittle boudinage. No continuous anhydrite layers are preserved, and halite has acted as a sealing matrix embedding the disrupted anhydrite fragments prohibiting any potential migration pathways for fluids. Thus, anhydrite should not have a negative effect on the barrier properties of the Gorleben rock salts investigated in this study.

  3. Microfabricated device and method for multiplexed electrokinetic focusing of fluid streams and a transport cytometry method using same

    DOEpatents

    Jacobson, Stephen C.; Ramsey, J. Michael

    2000-01-01

    A microfabricated device and method for electrokinetic transport of a liquid phase biological or chemical material is described. In accordance with one aspect of the present invention there is provided a microchip that is adapted for the simultaneous spatial confinement of electrokinetically driven fluidic material streams on a substrate. The apparatus includes a focusing chamber formed in a surface of the substrate and in fluid communication with two sample fluid channels and three focusing fluid channels. The device further includes electromotive means operatively connected to the sources of the sample fluid and the source of focusing fluid for electrokinetically driving the respective streams of the sample and focusing fluids through the respective channels into the focusing chamber such that the focusing fluid streams spatially confine the first and second sample fluid streams within the focusing chamber. In accordance with another aspect of this invention, there is provided a cytometry method for analyzing microscopic particles in a fluid medium on a microchip by utilizing the focusing function of the microchip. In the disclosed cytometry process the width of the fluid stream is narrowed in the focusing chamber. The microscopic particles in the focused sample fluid are then detected and/or measured using light scattering or other techniques.

  4. Micro-Fabricated Solid-State Radiation Detectors for Active Personal Dosimetry

    NASA Technical Reports Server (NTRS)

    Wrbanek, John D.; Wrbanek, Susan Y.; Fralick, Gustave C.; Chen, Liang-Yu

    2007-01-01

    Active radiation dosimetry is important to human health and equipment functionality for space applications outside the protective environment of a space station or vehicle. This is especially true for long duration missions to the moon, where the lack of a magnetic field offers no protection from space radiation to those on extravehicular activities. In order to improve functionality, durability and reliability of radiation dosimeters for future NASA lunar missions, single crystal silicon carbide devices and scintillating fiber detectors are currently being investigated for applications in advanced extravehicular systems. For many years, NASA Glenn Research Center has led significant efforts in silicon carbide semiconductor technology research and instrumentation research for sensor applications under extreme conditions. This report summarizes the technical progress and accomplishments toward characterization of radiation-sensing components for the recommendation of their fitness for advanced dosimetry development.

  5. Thin film metallic sensors in an alternating magnetic field for magnetic nanoparticle hyperthermia cancer therapy

    NASA Astrophysics Data System (ADS)

    Hussein, Z. A.; Boekelheide, Z.

    In magnetic nanoparticle hyperthermia in an alternating magnetic field for cancer therapy, it is important to monitor the temperature in situ. This can be done optically or electrically, but electronic measurements can be problematic because conducting parts heat up in a changing magnetic field. Microfabricated thin film sensors may be advantageous because eddy current heating is a function of size, and are promising for further miniaturization of sensors and fabrication of arrays of sensors. Thin films could also be used for in situ magnetic field sensors or for strain sensors. For a proof of concept, we fabricated a metallic thin film resistive thermometer by photolithographically patterning a 500Å Au/100Å Cr thin film on a glass substrate. Measurements were taken in a solenoidal coil supplying 0.04 T (rms) at 235 kHz with the sensor parallel and perpendicular to the magnetic field. In the parallel orientation, the resistive thermometer mirrored the background heating from the coil, while in the perpendicular orientation self-heating was observed due to eddy current heating of the conducting elements by Faraday's law. This suggests that metallic thin film sensors can be used in an alternating magnetic field, parallel to the field, with no significant self-heating.

  6. Nano- and micro-fabrication of perfluorinated polymers using quantum beam technology

    NASA Astrophysics Data System (ADS)

    Miyoshi, Nozomi; Oshima, Akihiro; Urakawa, Tatsuya; Fukutake, Naoyuki; Nagai, Hiroyuki; Gowa, Tomoko; Takasawa, Yuya; Takahashi, Tomohiro; Numata, Yukari; Katoh, Takanori; Katoh, Etsuko; Tagawa, Seiichi; Washio, Masakazu

    2011-02-01

    Micro- and nano-fabrication researches of various perfluorinated polymers carried out recently both by synchrotron radiation (SR) direct photo-etching and by focused ion beam (FIB) direct mask less etching are reviewed. After the irradiation, the etching depth of the fabricated samples has been evaluated by optical microscope and scanning electron microscope. SR-induced surface modifications were studied by solid-state 19F nuclear magnetic resonance (NMR) spectroscopy and differential scanning calorimeter (DSC) analysis. It was found that the etching rate of FEP at 140 °C was highest and that of PTFE and PFA at 140 °C was lower in the SR etching. It was found that crosslinking reactions were induced by SR irradiation at the region within about 50 μm from the irradiated surface. FIB mask less etching showed very attractive features for nano-scale fabrications. The aspect ratio for crosslinked PTFE (RX-PTFE) reached 390. In addition, the nano-scale controlled structures with high aspect and quality of RX-PTFE were obtained without solid debris.

  7. Magnetic susceptibility of the normal-superconducting transition in high-purity single-crystal α-uranium

    NASA Astrophysics Data System (ADS)

    O'Brien, J. L.; Hamilton, A. R.; Clark, R. G.; Mielke, C. H.; Smith, J. L.; Cooley, J. C.; Rickel, D. G.; Starrett, R. P.; Reilly, D. J.; Lumpkin, N. E.; Hanrahan, R. J.; Hults, W. L.

    2002-08-01

    We report complex ac magnetic susceptibility measurements of a superconducting transition in very high-quality single-crystal α-uranium using microfabricated coplanar magnetometers. We identify an onset of superconductivity at T~0.7 K in both the real and imaginary components of the susceptibility which is confirmed by resistivity data. A superconducting volume fraction argument, based on a comparison with a calibration YBa2Cu3O7-δ sample, indicates that superconductivity in these samples may be filamentary. Our data also demonstrate the sensitivity of the coplanar micro-magnetometers, which are ideally suited to measurements in pulsed magnetic fields exceeding 100 T.

  8. Continuous Monitoring of Glucose in Subcutaneous Tissue Using Microfabricated Differential Affinity Sensors

    PubMed Central

    Huang, Xian; Leduc, Charles; Ravussin, Yann; Li, Siqi; Davis, Erin; Song, Bing; Wang, Qian; Accili, Domenico; Leibel, Rudolph; Lin, Qiao

    2012-01-01

    Objective We describe miniaturized differential glucose sensors based on affinity binding between glucose and a synthetic polymer. The sensors possess excellent resistance to environmental disturbances and can potentially allow wireless measurements of glucose concentrations within interstitial fluid in subcutaneous tissue for long-term, stable continuous glucose monitoring (CGM). Methods The sensors are constructed using microelectromechanical systems (MEMS) technology and exploit poly(N-hydroxy-ethyl acrylamide-ran-3-acrylamidophenylboronic acid) (PHEAA-ran-PAAPBA), a glucose-binding polymer with excellent specificity, reversibility, and stability. Two sensing approaches have been investigated, which respectively, use a pair of magnetically actuated diaphragms and perforated electrodes to differentially measure the glucose-binding-induced changes in the viscosity and permittivity of the PHEAA-ran-PAAPBA solution with respect to a reference, glucose-unresponsive polymer solution. Results In vivo characterization of the MEMS affinity sensors were performed by controlling blood glucose concentrations of laboratory mice by exogenous glucose and insulin administration. The sensors experienced an 8–30 min initialization period after implantation and then closely tracked commercial capillary glucose meter readings with time lags ranging from 0–15 min during rapid glucose concentration changes. Clarke error grid plots obtained from sensor calibration suggest that, for the viscometric and dielectric sensors, respectively, approximately 95% (in the hyperglycemic range) and 84% (ranging from hypoglycemic to hyperglycemic glucose concentrations) of measurement points were clinically accurate, while 5% and 16% of the points were clinically acceptable. Conclusions The miniaturized MEMS sensors explore differential measurements of affinity glucose recognition. In vivo testing demonstrated excellent accuracy and stability, suggesting that the devices hold the potential to

  9. Tissue-compliant neural implants from microfabricated carbon nanotube multilayer composite.

    PubMed

    Zhang, Huanan; Patel, Paras R; Xie, Zhixing; Swanson, Scott D; Wang, Xueding; Kotov, Nicholas A

    2013-09-24

    Current neural prosthetic devices (NPDs) induce chronic inflammation due to complex mechanical and biological reactions related, in part, to staggering discrepancies of mechanical properties with neural tissue. Relatively large size of the implants and traumas to blood-brain barrier contribute to inflammation reactions, as well. Mitigation of these problems and the realization of long-term brain interface require a new generation of NPDs fabricated from flexible materials compliant with the brain tissue. However, such materials will need to display hard-to-combine mechanical and electrical properties which are not available in the toolbox of classical neurotechnology. Moreover, these new materials will concomitantly demand different methods of (a) device micromanufacturing and (b) surgical implantation in brains because currently used processes take advantage of high stiffness of the devices. Carbon nanotubes (CNTs) serve as a promising foundation for such materials because of their record mechanical and electrical properties, but CNT-based tissue-compliant devices have not been realized yet. In this study, we formalize the mechanical requirements to tissue-compliant implants based on critical rupture strength of brain tissue and demonstrate that miniature CNT-based devices can satisfy these requirements. We fabricated them using MEMS-like technology and miniaturized them so that at least two dimensions of the electrodes would be comparable to brain tissue cells. The nanocomposite-based flexible neural electrodes were implanted into the rat motor cortex using a surgical procedure specifically designed for soft tissue-compliant implants. The post-surgery implant localization in the motor cortex was successfully visualized with magnetic resonance and photoacoustic imaging. In vivo functionality was demonstrated by successful registration of the low-frequency neural recording in the live brain of anesthetized rats. Investigation of inflammation processes around these

  10. Process optimization in high-average-power ultrashort pulse laser microfabrication: how laser process parameters influence efficiency, throughput and quality

    NASA Astrophysics Data System (ADS)

    Schille, Joerg; Schneider, Lutz; Loeschner, Udo

    2015-09-01

    In this paper, laser processing of technical grade stainless steel and copper using high-average-power ultrashort pulse lasers is studied in order to gain deeper insight into material removal for microfabrication. A high-pulse repetition frequency picosecond and femtosecond laser is used in conjunction with high-performance galvanometer scanners and an in-house developed two-axis polygon scanner system. By varying the processing parameters such as wavelength, pulse length, fluence and repetition rate, cavities of standardized geometry are fabricated and analyzed. From the depths of the cavities produced, the ablation rate and removal efficiency are estimated. In addition, the quality of the cavities is evaluated by means of scanning electron microscope micrographs or rather surface roughness measurements. From the results obtained, the influence of the machining parameters on material removal and machining quality is discussed. In addition, it is shown that both material removal rate and quality increase by using femtosecond compared to picosecond laser pulses. On stainless steel, a maximum throughput of 6.81 mm3/min is achieved with 32 W femtosecond laser powers; if using 187 W picosecond laser powers, the maximum is 15.04 mm3/min, respectively. On copper, the maximum throughputs are 6.1 mm3/min and 21.4 mm3/min, obtained with 32 W femtosecond and 187 W picosecond laser powers. The findings indicate that ultrashort pulses in the mid-fluence regime yield most efficient material removal. In conclusion, from the results of this analysis, a range of optimum processing parameters are derived feasible to enhance machining efficiency, throughput and quality in high-rate micromachining. The work carried out here clearly opens the way to significant industrial applications.

  11. Isolation and detection of single molecules on paramagnetic beads using sequential fluid flows in microfabricated polymer array assemblies.

    PubMed

    Kan, Cheuk W; Rivnak, Andrew J; Campbell, Todd G; Piech, Tomasz; Rissin, David M; Mösl, Matthias; Peterça, Andrej; Niederberger, Hans-Peter; Minnehan, Kaitlin A; Patel, Purvish P; Ferrell, Evan P; Meyer, Raymond E; Chang, Lei; Wilson, David H; Fournier, David R; Duffy, David C

    2012-03-01

    We report a method for isolating individual paramagnetic beads in arrays of femtolitre-sized wells and detecting single enzyme-labeled proteins on these beads using sequential fluid flows in microfabricated polymer array assemblies. Arrays of femtolitre-sized wells were fabricated in cyclic olefin polymer (COP) using injection moulding based on DVD manufacturing. These arrays were bonded to a complementary fluidic structure that was also moulded in COP to create an enclosed device to allow delivery of liquids to the arrays. Enzyme-associated, paramagnetic beads suspended in aqueous solutions of enzyme substrate were delivered fluidically to the array such that one bead per well was loaded by gravity. A fluorocarbon oil was then flowed into the device to remove excess beads from the surface of the array, and to seal and isolate the femtolitre-sized wells containing beads and enzyme substrate. The device was then imaged using standard fluorescence imaging to determine which wells contained single enzyme molecules. The analytical performance of this device as the detector for digital ELISA compared favourably to the standard method, i.e., glass arrays mechanically sealed against a silicone gasket; prostate specific antigen (PSA) could be detected from 0.011 pg mL(-1) up to 100 pg mL(-1). The use of an enclosed fluidic device to isolate beads in single-molecule arrays offers a multitude of advantages for low-cost manufacturing, ease of automation, and instrument development to enable applications in biomarker validation and medical diagnosis. PMID:22179487

  12. Conventional and enantioselective gas chromatography with microfabricated planar columns for analysis of real-world samples of plant volatile fraction.

    PubMed

    Cagliero, C; Galli, S; Galli, M; Elmi, I; Belluce, M; Zampolli, S; Sgorbini, B; Rubiolo, P; Bicchi, C

    2016-01-15

    Within a project exploring the application of lab-on-chip GC to in-field analysis of the plant volatile fraction, this study evaluated the performance of a set of planar columns (also known as microchannels, MEMS columns, or microfabricated columns) of different dimensions installed in a conventional GC unit. Circular double-spiral-shaped-channel planar columns with different square/rectangular sections up to 2m long were applied to the analysis of both essential oils and headspace samples of a group of medicinal and aromatic plants (chamomile, peppermint, sage, rosemary, lavender and bergamot) and of standard mixtures of related compounds; the results were compared to those obtained with reference narrow-bore columns (l:5m, dc:0.1mm, df:0.1 μm). The above essential oils and headspaces were first analyzed quali-and quantitatively with planar columns statically coated with conventional stationary phases (5%-phenyl-polymethylsiloxane and auto-bondable nitroterephthalic-acid-modified polyethylene glycol), and then submitted to chiral recognition of their diagnostic markers, by enantioselective GC with a planar columns coated with a cyclodextrin derivative (30% 6(I-VII)-O-TBDMS-3(I-VII)-O-ethyl-2(I-VII)-O-ethyl-β-cyclodextrin in PS-086). Column characteristics and analysis conditions were first optimized to obtain suitable retention and efficiency for the samples investigated. The planar columns tested showed performances close to the reference conventional narrow-bore columns, with theoretical plate numbers per meter (N/m) ranging from 6100 to 7200 for those coated with the conventional stationary phases, and above 5600 for those with the chiral selector. PMID:26733393

  13. Silicon microfabricated device for non-sheath-flow cytometer-based chemical analysis and microchannel flow sensing

    NASA Astrophysics Data System (ADS)

    Huang, Ming-Chieh

    This dissertation presents a method and apparatus for rapid measurement of fluid pH value in a microscale volume. The fluorescence of indicators immobilized on polymer microbeads is a function of the concentration of an analyte. This was determined in a silicon microfabricated flow channel. The sizes of microbeads can be determined by the scattering signal, so this system could be used to analyze several analytes at the same time by using beads of different sizes which are sensitive to different analytes. The fluorescent indicator Carboxy-SNAFL I was immobilized by Molecular Probes on amino-functionalized polystyrene beads of 5 mum diameter. These pH-sensitive microbeads were used in this apparatus to measure the pH of sample solutions. The intensities of two fluorescent peaks (at 560 nm and at 620 run) were measured, their ratio was dependent on the pH value of the analyte. We discriminated bead diameter by monitoring the intensity of the scattered excitation signal. In the measurement of the light scattering signal, the standard deviation/bead diameter (SD/D) for the 10.3 mum beads was ˜26%. The major error is caused by varying positions of the beads in the microchannel. In order to decrease the SD/D of scattering signal and thus increase the number of distinct bead types that can be identified, a low Reynolds number silicon/pyrex microfluidic device that forces particles flowing in a microchannel to a tightly-focused equilibrium position was designed and fabricated. When scattering signals from 10 mum polymer beads were measured, we observed that the tight equilibrium position attained by the particles resulted in a much smaller standard deviation of the scattering signal than was observed in other microflow channel devices that did not focus the particles to equilibrium positions. Another applications of this device is also discussed. We show that this particle-focusing channel may be used in a micro-fluidic flow sensor.

  14. Computer numerical control (CNC) lithography: light-motion synchronized UV-LED lithography for 3D microfabrication

    NASA Astrophysics Data System (ADS)

    Kim, Jungkwun; Yoon, Yong-Kyu; Allen, Mark G.

    2016-03-01

    This paper presents a computer-numerical-controlled ultraviolet light-emitting diode (CNC UV-LED) lithography scheme for three-dimensional (3D) microfabrication. The CNC lithography scheme utilizes sequential multi-angled UV light exposures along with a synchronized switchable UV light source to create arbitrary 3D light traces, which are transferred into the photosensitive resist. The system comprises a switchable, movable UV-LED array as a light source, a motorized tilt-rotational sample holder, and a computer-control unit. System operation is such that the tilt-rotational sample holder moves in a pre-programmed routine, and the UV-LED is illuminated only at desired positions of the sample holder during the desired time period, enabling the formation of complex 3D microstructures. This facilitates easy fabrication of complex 3D structures, which otherwise would have required multiple manual exposure steps as in the previous multidirectional 3D UV lithography approach. Since it is batch processed, processing time is far less than that of the 3D printing approach at the expense of some reduction in the degree of achievable 3D structure complexity. In order to produce uniform light intensity from the arrayed LED light source, the UV-LED array stage has been kept rotating during exposure. UV-LED 3D fabrication capability was demonstrated through a plurality of complex structures such as V-shaped micropillars, micropanels, a micro-‘hi’ structure, a micro-‘cat’s claw,’ a micro-‘horn,’ a micro-‘calla lily,’ a micro-‘cowboy’s hat,’ and a micro-‘table napkin’ array.

  15. Performance of Magnetic Penetration Thermometers for X-Ray Astronomy

    NASA Technical Reports Server (NTRS)

    Nagler, P. C.; Adams, J. S.; Balvin, M. A.; Bandler, S. R.; Denis, K. L.; Hsieh, W. T.; Kelly, D. P.; Porst, J. P.; Sadleir, J. E.; Seidel, G. M.; Smith, S. J.; Stevenson, T. R.

    2012-01-01

    The ideal X-ray camera for astrophysics would have more than a million pixels and provide an energy resolution of better than leV FWHM for energies up to 10 keY. We have microfabricated and characterized thin-film magnetic penetration thermometers (MPTs) that show great promise towards meeting these capabilities. MPTs operate in similar fashion to metallic magnetic calorimeters (MMCs), except that a superconducting sensor takes the place of a paramagnetic sensor and it is the temperature dependence of the superconductor's diamagnetic response that provides the temperature sensitivity. We present a description of the design and performance of our prototype thin-film MPTs with MoAu bilayer sensors, which have demonstrated an energy resolution of approx 2 eV FWHM at 1.5 keY and 4.3 eV FWHM at 5.9 keY.

  16. Note: On-chip multifunctional fluorescent-magnetic Janus helical microswimmers

    NASA Astrophysics Data System (ADS)

    Hwang, G.; Decanini, D.; Leroy, L.; Haghiri-Gosnet, A. M.

    2016-03-01

    Microswimmers integrated into microfluidic devices that are capable of self-illumination through fluorescence could revolutionize many aspects of technology, especially for biological applications. Few illumination and propulsion techniques of helical microswimmers inside microfluidic channels have been demonstrated. This paper presents the fabrication, detachment, and magnetic propulsions of multifunctional fluorescent-magnetic helical microswimmers integrated inside microfluidics. The fabrication process is based on two-photon laser lithography to pattern 3-D nanostructures from fluorescent photoresist coupled with conventional microfabrication techniques for magnetic thin film deposition by shadowing. After direct integration inside a microfluidic device, injected gas bubble allows gentle detachment of the integrated helical microswimmers whose magnetic propulsion can then be directly applied inside the microfluidic channel using external electromagnetic coil setup. With their small scale, fluorescence, excellent resistance to liquid/gas surface tension, and robust propulsion capability inside the microfluidic channel, the microswimmers can be used as high-resolution and large-range mobile micromanipulators inside microfluidic channels.

  17. Design and implementation of a magnetically suspended microrobotic pick-and-place system

    NASA Astrophysics Data System (ADS)

    Shameli, Ehsan; Craig, David G.; Khamesee, Mir Behrad

    2006-04-01

    Micromanipulation is an emerging technology in such diverse areas as precision engineering, microfabrication, and microsurgery. Each of these areas impose certain technological constraints and requirements in fabrication, actuation, and control. This paper performs a review on the latest technologies of microrobotic actuation techniques and suggests a suitable technique for the actuation of a magnetically levitated microrobot. The microrobot, suspended in an externally produced magnetic field, consists of a gripper attached to a series of permanent magnets and is capable of simple pick and place tasks. A number of electromagnets produce the external magnetic field and three laser sensors feedback the position of the levitated microrobot. Through finite element analysis, performance of the levitation system was investigated, and simulations and experiments were carried out to demonstrate the practical capabilities of the proposed system.

  18. Design, microfabrication, and characterization of a moulded PDMS/SU-8 inkjet dispenser for a Lab-on-a-Printer platform technology with disposable microfluidic chip.

    PubMed

    Bsoul, Anas; Pan, Sheng; Cretu, Edmond; Stoeber, Boris; Walus, Konrad

    2016-08-16

    In this paper, we present a disposable inkjet dispenser platform technology and demonstrate the Lab-on-a-Printer concept, an extension of the ubiquitous Lab-on-a-Chip concept, whereby microfluidic modules are directly integrated into the printhead. The concept is demonstrated here through the integration of an inkjet dispenser and a microfluidic mixer enabling control over droplet composition from a single nozzle in real-time during printing. The inkjet dispenser is based on a modular design platform that enables the low-cost microfluidic component and the more expensive actuation unit to be easily separated, allowing for the optional disposal of the former and reuse of the latter. To limit satellite droplet formation, a hydrophobic-coated and tapered micronozzle was microfabricated and integrated with the fluidics to realize the dispenser. The microfabricated devices generated droplets with diameters ranging from 150-220 μm, depending mainly on the orifice diameter, with printing rates up to 8000 droplets per second. The inkjet dispenser is capable of dispensing materials with a viscosity up to ∼19 mPa s. As a demonstration of the inkjet dispenser function and application, we have printed type I collagen seeded with human liver carcinoma cells (cell line HepG2), to form patterned biological structures. PMID:27444216

  19. Investigation of magnetic microdiscs for bacterial pathogen detection

    NASA Astrophysics Data System (ADS)

    Castillo-Torres, Keisha Y.; Garraud, Nicolas; Arnold, David P.; McLamore, Eric S.

    2016-05-01

    Despite strict regulations to control the presence of human pathogens in our food supply, recent foodborne outbreaks have heightened public concern about food safety and created urgency to improve methods for pathogen detection. Herein we explore a potentially portable, low-cost system that uses magnetic microdiscs for the detection of bacterial pathogens in liquid samples. The system operates by optically measuring the rotational dynamics of suspended magnetic microdiscs functionalized with pathogen-binding aptamers. The soft ferromagnetic (Ni80Fe20) microdiscs exhibit a closed magnetic spin arrangement (i.e. spin vortex) with zero magnetic stray field, leading to no disc agglomeration when in free suspension. With very high surface area for functionalization and volumes 10,000x larger than commonly used superparamagnetic nanoparticles, these 1.5-μm-diameter microdiscs are well suited for tagging, trapping, actuating, or interrogating bacterial targets. This work reports a wafer-level microfabrication process for fabrication of 600 million magnetic microdiscs per substrate and measurement of their rotational dynamics response. Additionally, the biofunctionalization of the microdiscs with DNA aptamers, subsequent binding to E. coli bacteria, and their magnetic manipulation is reported.

  20. Ferromagnetic resonance properties of granular Co-Cr-Pt films measured by micro-fabricated coplanar waveguides

    NASA Astrophysics Data System (ADS)

    Kobayashi, T.; Ishida, N.; Sekiguchi, K.; Nozaki, Y.

    2012-04-01

    Ferromagnetic resonance (FMR) spectroscopy of granular Co-Cr-Pt films has been studied by means of a vector network analyzer. Though the granular Co-Cr-Pt films have weak magnetic susceptibility, the structural optimization of a coplanar waveguide (CPW) enables the measurement of the weak FMR signal of granular Co-Cr-Pt films, which are a promising medium for magnetic recording. The observed FMR spectra are consistent with the Kittel formula. The optimization of the CPW is well established by our simple model, providing a method to explore the basic magnetic properties of a granular medium.

  1. Microfabrication services at INO

    NASA Astrophysics Data System (ADS)

    Alain, Christine; Jerominek, Hubert; Topart, Patrice A.; Pope, Timothy D.; Picard, Francis; Cayer, Felix; Larouche, Carl; Leclair, Sebastien; Tremblay, Bruno

    2003-01-01

    MEMS (Micro Electro Mechanical Systems) technology has expanded widely over the last decade in terms of its use in devices and instrumentation for diverse applications. However, access to versatile foundry services for MEMS fabrication is still limited. At INO, the presence of a multidisciplinary team and a complete tool set allow us to offer unique MEMS foundry-type services. These services include: design, prototyping, fabrication, packaging and testing of various MEMS and MOEMS devices. The design of a device starts with the evaluation of different structures adapted to a given application. Computer simulation tools, like IntelliSuite, ANSYS or custom software are used to evaluate the mechanical, optical, thermal and electromechanical performances. Standard IC manufacturing techniques such as metal, dielectric and semiconductor film deposition and etching as well as photolithographic pattern transfer are available. In addition, some unique techniques such as on-wafer lithography by laser writing, gray-scale mask lithography, thick photoresist lithography, selective electroplating, injection moulding and UV-assisted moulding are available to customers. The hermetic packaging and a novel patented wafer-level micropackaging are also applied. This multifaceted expertise has been utilized to manufacturing of several types of MEMS devices as well as complex instruments including micromirror-type devices, microfilters, IR microbolometric detector arrays, complete cameras and multipurpose sensors.

  2. Microfabricated therapeutic actuator mechanisms

    DOEpatents

    Northrup, Milton A.; Ciarlo, Dino R.; Lee, Abraham P.; Krulevitch, Peter A.

    1997-01-01

    Electromechanical microstructures (microgrippers), either integrated circuit (IC) silicon-based or precision machined, to extend and improve the application of catheter-based interventional therapies for the repair of aneurysms in the brain or other interventional clinical therapies. These micromechanisms can be specifically applied to release platinum coils or other materials into bulging portions of the blood vessels also known as aneurysms. The "micro" size of the release mechanism is necessary since the brain vessels are the smallest in the body. Through a catheter more than one meter long, the micromechanism located at one end of the catheter can be manipulated from the other end thereof. The microgripper (micromechanism) of the invention will also find applications in non-medical areas where a remotely actuated microgripper or similar actuator would be useful or where micro-assembling is needed.

  3. Microfabricated therapeutic actuator mechanisms

    DOEpatents

    Northrup, M.A.; Ciarlo, D.R.; Lee, A.P.; Krulevitch, P.A.

    1997-07-08

    Electromechanical microstructures (microgrippers), either integrated circuit (IC) silicon-based or precision machined, to extend and improve the application of catheter-based interventional therapies for the repair of aneurysms in the brain or other interventional clinical therapies. These micromechanisms can be specifically applied to release platinum coils or other materials into bulging portions of the blood vessels also known as aneurysms. The ``micro`` size of the release mechanism is necessary since the brain vessels are the smallest in the body. Through a catheter more than one meter long, the micromechanism located at one end of the catheter can be manipulated from the other end thereof. The microgripper (micromechanism) of the invention will also find applications in non-medical areas where a remotely actuated microgripper or similar actuator would be useful or where micro-assembling is needed. 22 figs.

  4. Decal transfer microfabrication

    DOEpatents

    Nuzzo, Ralph G.; Childs, William Robert

    2004-10-19

    A method of making a microstructure includes forming a pattern in a surface of a silicon-containing elastomer, oxidizing the pattern, contacting the pattern with a substrate; and bonding the oxidized pattern and the substrate such that the pattern and the substrate are irreversibly attached. The silicon-containing elastomer may be removably attached to a transfer pad.

  5. Microfabricated Liquid Rocket Motors

    NASA Technical Reports Server (NTRS)

    Epstein, Alan H.; Joppin, C.; Kerrebrock, J. L.; Schneider, Steven J. (Technical Monitor)

    2003-01-01

    Under NASA Glenn Research Center sponsorship, MIT has developed the concept of micromachined, bipropellant, liquid rocket engines. This is potentially a breakthrough technology changing the cost-performance tradeoffs for small propulsion systems, enabling new applications, and redefining the meaning of the term low-cost-access-to-space. With this NASA support, a liquid-cooled, gaseous propellant version of the thrust chamber and nozzle was designed, built, and tested as a first step. DARPA is currently funding MIT to demonstrate turbopumps and controls. The work performed herein was the second year of a proposed three-year effort to develop the technology and demonstrate very high power density, regeneratively cooled, liquid bipropellant rocket engine thrust chamber and nozzles. When combined with the DARPA turbopumps and controls, this work would enable the design and demonstration of a complete rocket propulsion system. The original MIT-NASA concept used liquid oxygen-ethanol propellants. The military applications important to DARPA imply that storable liquid propellants are needed. Thus, MIT examined various storable propellant combinations including N2O4 and hydrazine, and H2O2 and various hydrocarbons. The latter are preferred since they do not have the toxicity of N2O4 and hydrazine. In reflection of the newfound interest in H2O2, it is once again in production and available commercially. A critical issue for the microrocket engine concept is cooling of the walls in a regenerative design. This is even more important at microscale than for large engines due to cube-square scaling considerations. Furthermore, the coolant behavior of rocket propellants has not been characterized at microscale. Therefore, MIT designed and constructed an apparatus expressly for this purpose. The report details measurements of two candidate microrocket fuels, JP-7 and JP-10.

  6. Microfabricated cylindrical ion trap

    DOEpatents

    Blain, Matthew G.

    2005-03-22

    A microscale cylindrical ion trap, having an inner radius of order one micron, can be fabricated using surface micromachining techniques and materials known to the integrated circuits manufacturing and microelectromechanical systems industries. Micromachining methods enable batch fabrication, reduced manufacturing costs, dimensional and positional precision, and monolithic integration of massive arrays of ion traps with microscale ion generation and detection devices. Massive arraying enables the microscale cylindrical ion trap to retain the resolution, sensitivity, and mass range advantages necessary for high chemical selectivity. The microscale CIT has a reduced ion mean free path, allowing operation at higher pressures with less expensive and less bulky vacuum pumping system, and with lower battery power than conventional- and miniature-sized ion traps. The reduced electrode voltage enables integration of the microscale cylindrical ion trap with on-chip integrated circuit-based rf operation and detection electronics (i.e., cell phone electronics). Therefore, the full performance advantages of microscale cylindrical ion traps can be realized in truly field portable, handheld microanalysis systems.

  7. Microfabricated incandescent lamps.

    PubMed

    Mastrangelo, C H; Muller, R S; Kumar, S

    1991-03-01

    A silicon filament vacuum sealed incandescent light source has been fabricated using IC technology. The incandescent source consists of a heavily doped p(+) polysilicon filament coated with silicon nitride and enclosed in a vacuum sealed ( approximately 80-mT) cavity in the silicon chip surface. The filament is electrically heated to reach incandescence at a temperature near 1400 K. The power required to achieve this temperature for a filament 510 x 5 x 1 microm(3) is 5 mW yielding a total optical power of 250 microW with a peak distribution wavelength near 2.5 microm. The radiation emitted by this source approximately follows Lambert's cosine law. The energy conversion efficiency is 5%. PMID:20582072

  8. Specialty magnets

    SciTech Connect

    Halbach, K.

    1986-07-01

    A number of basic conceptual designs are explained for magnet systems that use permanent magnet materials. Included are iron free multipoles and hybrid magnets. Also appended is a discussion of the manufacturing process and magnetic properties of some permanent magnet materials. (LEW)

  9. Utilisation de procedes de microfabrication pour la realisation de modules thermoelectriques a base d'alliages (Bi,Sb)2(Te,Se)3

    NASA Astrophysics Data System (ADS)

    Kashi, Siamak

    The production of thermoelectric devices uses nearly handmade techniques as an industry standard. These techniques are not suitable for the fabrication of smaller devices, where thermoelements are shorter than 1 millimetre. Researchers are focusing on how to decrease the height of thermoelements in a device, to the extent of depositing thermoelectric thin films. However, the best thermoelectric performances are obtained on modules fabricated from bulk material. Many tests were made to decrease the overall size of these devices, but until now, they would not permit to obtain the same range of performances as industrial devices. The aim of this project is to use microfabrication processes to obtain high power density thermoelectric devices. The precision obtained with the use of microfabrication techniques and automated methods has the potential to increase the performance and the industrial production of these devices. Fabrication steps were designed and tested in the facilities of the Ecole Polytechnique de Montreal to create hot extruded p-type and n-type (Bi,Sb)2(Te,Se)3 alloy based thermoelectric devices. These steps can be listed in three different categories, surface treatments, microfabrication methods and hot assembly. After cutting, p-type and n-type wafers were polished, underwent electropolishing and chemical etching before a diffusion barrier layer of nickel was deposited. Photolithography printed a pattern on the samples, where tin was then electroplated. A first assembly allowed soldering samples of each conduction type to alumina plates, before cutting the sample to free the thermoelements. A final assembly then created the finished devices by soldering of the two parts containing p-type and n-type thermoelements. The produced devices were functional, validating the designed steps. Electrical characterization of the best modules obtained indicate that the electromotive force is comparable to that of commercial modules under the same conditions

  10. Non-steady state deformation at decaying stresses indicated by microfabrics in peridotites from the Balmuccia complex in the Western Alps

    NASA Astrophysics Data System (ADS)

    Matysiak, A. K.; Trepmann, C.

    2010-12-01

    The microfabrics of deformed peridotites from Balmuccia complex in the Western European Alps are investigated by optical and electron microscopic techniques (SEM/EBSD, TEM). The peridotites are mostly lherzolitic with 65-98% olivine, 5-30% orthopyroxene, 1-15% clinopyroxene and 1-2% spinel. Shear zones are 50 µm to 250 µm wide and consist of ultra fine-grained (< 1 µm in diameter) and recrystallized olivine (up to 70 µm in diameter), ortho- and clinopyroxene. Spinel grains within and next to the shear zone are strongly sheared and lengthened. The amount of recrystallized grains decreases with distance to shear zones, which occur in conjugate sets. The recrystallized aggregates outside the shear zones are monomineralic. The strong foliation of the samples is mainly defined by flattened olivine porphyroclasts that are separated by bands of recrystallized olivine grains with same composition compared to the porphyroclasts. Recrystallized grains also occur in transgranular bands of porphyroclasts. The distribution of recrystallized grains suggests that they have overgrown inter- and intragranular cracks and thus indicate a preceding stage with brittle deformation. Grain boundaries of olivine porphyroclasts are sutured and surrounded by recrystallized grains, indicating strain-induced recrystallization. Olivine porphyroclasts are strongly deformed as shown by the abundant presence of intense undulous extinction and crinkly deformation lamellae subparallel (100) which are a few microns wide and show a misorientation angle < 2°. In TEM, the latter features are characterized by straight screw dislocations parallel [001] and low angle tilt boundaries parallel (100), indicating activation of at least two slip systems: (100)[001] and (010)[100] respectively. These features are interpreted to result from an initial glide-controlled deformation at high differential stresses, which are modified by recovery at decaying stresses. Porphyroclasts of ortho- and clinopyroxene

  11. Stable, Microfabricated Thin Layer Chromatography Plates without Volume Distortion on Patterned, Carbon and Al2O3-Primed Carbon Nanotube Forests

    SciTech Connect

    Jensen, David S.; Kanyal, Supriya S.; Gupta, Vipul; Vail, Michael A.; Dadson, Andrew; Engelhard, Mark H.; Vanfleet, Richard; Davis, Robert C.; Linford, Matthew R.

    2012-09-28

    In a recent report (Song, J.; et al., Advanced Functional Materials 2011, 21, 1132-1139) some of us described the fabrication of thin layer chromatography (TLC) plates from patterned carbon nanotube (CNT) forests, which were directly infiltrated/coated with silicon by low pressure chemical vapor deposition (LPCVD) of silicon using SiH4. Following infiltration, the nanotubes were removed from the assemblies and the silicon simultaneously converted to SiO2 in a high temperature oxidation step. However, while straightforward, this process had some shortcomings, not the least of which was some distortion of the lithographically patterned features during the volume expansion that accompanied oxidation. Herein we overcome theis issue and also take substantial steps forward in the microfabrication of TLC plates by showing: (i) A new method for creating an adhesion promotion layer on CNT forests by depositing a few nanometers of carbon followed by atomic layer deposition (ALD) of Al2O3. This method for appears to be new, and X-ray photoelectron spectroscopy confirms the expected presence of oxygen after carbon deposition. ALD of Al2O3 alone and in combination with the carbon on patterned CNT forests was also explored as an adhesion promotion layer for CNT forest infiltration. (ii) Rapid, conformal deposition of an inorganic material that does not require subsequent oxidation: fast pseudo-ALD growth of SiO2 via alumina catalyzed deposition of tris(tert-butoxy)silanol onto the carbon/Al2O3-primed CNT forests. (iii) Faithful reproduction of the features in the masks used to microfabricate the TLC plates (M-TLC) this advance springs from the previous two points. (iv) A bonded (amino) phase on a CNT-templated microfabricated TLC plate. (v) Fast, highly efficient (125,000 - 225,000 N/m) separations of fluorescent dyes on M-TLC plates. (vi) Extensive characterization of our new materials by TEM, SEM, EDAX, DRIFT, and XPS. (vii) A substantially lower process temperature for the

  12. Spatiotemporal magnetization dynamics of patterned nickel(80)iron(20)

    NASA Astrophysics Data System (ADS)

    Belov, Miroslav

    The thesis is composed of several projects, each one of them necessary for a comprehensive study of micromagnetics. In the first project, a process for microfabrication of magnetic structures, based on a deposition by a DC magnetron sputtering and patterning of small elements using electron-beam lithography and lift-off was developed. In the second project, an ultrafast time-resolved scanning magneto-optical Kerr microscope was built to detect changes of the polar component of magnetization in stroboscopic measurement. This computer-controlled experiment consists of a femtosecond laser, a piezoelectric stage with nanometer resolution, an optical delay line, a pumping photodiode and a detecting scheme. Images and curves related to magnetization oscillations in internally patterned Ni80Fe20 elements were gathered, analyzed and discussed. A description of the temporal evolution and spatial distribution of magnetization oscillations was introduced in terms of broadband ferromagnetic resonance, spin waves and magnon-magnon interactions. Experimental data from pump-probe measurements on 15nm thick 4pm squares and 10 x 5 mum elliptical structures (uniform or with a circular pinhole) were taken, while longitudinally biased by DC magnetic fields. The magnon-magnon scattering and "indirect" damping initiated by domain structures are discussed. The influence of a lithographic pinhole (with a 240nm diameter, in a center of a 4micron square and in a focus of an ellipse) on magnetization oscillations was investigated, showing that the magnetization pattern around the pinhole significantly affects the modal oscillations of the platelet. The magnetization dynamics we also modeled via numerical simulations using the Landau-Lifshitz-Gilbert equation of motion. The results from the numerical analysis show very good quantitative agreement with the experimental data. This work is a step towards more elaborate manipulation of the allowed magnetic modes in complex thin film magnetic

  13. Polydimethylsiloxane films doped with NdFeB powder: magnetic characterization and potential applications in biomedical engineering and microrobotics.

    PubMed

    Iacovacci, V; Lucarini, G; Innocenti, C; Comisso, N; Dario, P; Ricotti, L; Menciassi, A

    2015-12-01

    This work reports the fabrication, magnetic characterization and controlled navigation of film-shaped microrobots consisting of a polydimethylsiloxane-NdFeB powder composite material. The fabrication process relies on spin-coating deposition, powder orientation and permanent magnetization. Films with different powder concentrations (10 %, 30 %, 50 % and 70 % w/w) were fabricated and characterized in terms of magnetic properties and magnetic navigation performances (by exploiting an electromagnet-based platform). Standardized data are provided, thus enabling the exploitation of these composite materials in a wide range of applications, from MEMS/microrobot development to biomedical systems. Finally, the possibility to microfabricate free-standing polymeric structures and the biocompatibility of the proposed composite materials is demonstrated. PMID:26554861

  14. Precision formed micro magnets: LDRD project summary report

    SciTech Connect

    CHRISTENSON,TODD R.; GARINO,TERRY J.; VENTURINI,EUGENE L.

    2000-02-01

    A microfabrication process is described that provides for the batch realization of miniature rare earth based permanent magnets. Prismatic geometry with features as small as 5 microns, thicknesses up through several hundred microns and with submicron tolerances may be accommodated. The processing is based on a molding technique using deep x-ray lithography as a means to generate high aspect-ratio precision molds from PMMA (poly methyl methacrylate) used as an x-ray photoresist. Subsequent molding of rare-earth permanent magnet (REPM) powder combined with a thermosetting plastic binder may take place directly in the PMMA mold. Further approaches generate an alumina form replicated from the PMMA mold that becomes an intermediate mold for pressing higher density REPM material and allows for higher process temperatures. Maximum energy products of 3--8 MGOe (Mega Gauss Oersted, 1 MGOe = 100/4{pi} kJ/m{sup 3}) are obtained for bonded isotropic forms of REPM with dimensions on the scale of 100 microns and up to 23 MGOe for more dense anisotropic REPM material using higher temperature processing. The utility of miniature precision REPMs is revealed by the demonstration of a miniature multipole brushless DC motor that possesses a pole-anisotropic rotor with dimensions that would otherwise prohibit multipole magnetization using a multipole magnetizing fixture at this scale. Subsequent multipole assembly also leads to miniaturized Halbach arrays, efficient magnetic microactuators, and mechanical spring-like elements which can offset miniaturized mechanical scaling behavior.

  15. Precision measurement of the branching fractions of the 5 p 1/2 2P state in +88Sr with a single ion in a microfabricated surface trap

    NASA Astrophysics Data System (ADS)

    Likforman, Jean-Pierre; Tugayé, Vincent; Guibal, Samuel; Guidoni, Luca

    2016-05-01

    We measured the branching fractions for the decay of the 5 p 1/2 2P state of +88Sr by applying a recently demonstrated photon-counting sequential method [M. Ramm, T. Pruttivarasin, M. Kokish, I. Talukdar, and H. Häffner, Phys. Rev. Lett. 111, 023004 (2013), 10.1103/PhysRevLett.111.023004] to a single ion laser cooled in a microfabricated surface trap. The branching fraction for the decay into the 5 s 1/2 2S ground level was found to be p =0.9449 (5 ) . This result is in good agreement with recent theoretical calculations but disagrees with previous experimental measurements, however affected by a one-order-of-magnitude larger uncertainty. This experiment demonstrates that microtrap technology is also applicable in the domain of precision measurements and spectroscopy.

  16. Fabrication of multi-layer polymeric micro-sieve having narrow slot pores with conventional ultraviolet-lithography and micro-fabrication techniques

    PubMed Central

    Ebrahimi Warkiani, Majid; Lou, Chao-Ping; Gong, Hai-Qing

    2011-01-01

    Fast detection of waterborne pathogens is important for securing the hygiene of drinking water. Detection of pathogens in water at low concentrations and minute quantities demands rapid and efficient enrichment methods in order to improve the signal-to-noise ratio of bio-sensors. We propose and demonstrate a low cost and rapid method to fabricate a multi-layer polymeric micro-sieve using conventional lithography techniques. The micro-fabricated micro-sieves are made of several layers of SU-8 photoresist using multiple coating and exposure steps and a single developing process. The obtained micro-sieves have good mechanical properties, smooth surfaces, high porosity (≈40%), and narrow pore size distribution (coefficient of variation < 3.33%). Sample loading and back-flushing using the multi-layer micro-sieve resulted in more than 90% recovery of pathogens, which showed improved performance than current commercial filters. PMID:22662051

  17. Neodymium Magnets.

    ERIC Educational Resources Information Center

    Wida, Sam

    1992-01-01

    Uses extremely strong neodymium magnets to demonstrate several principles of physics including electromagnetic induction, Lenz's Law, domain theory, demagnetization, the Curie point, and magnetic flux lines. (MDH)

  18. Parallel RNA extraction using magnetic beads and a droplet array

    PubMed Central

    Shi, Xu; Chen, Chun-Hong; Gao, Weimin; Meldrum, Deirdre R.

    2015-01-01

    Nucleic acid extraction is a necessary step for most genomic/transcriptomic analyses, but it often requires complicated mechanisms to be integrated into a lab-on-a-chip device. Here, we present a simple, effective configuration for rapidly obtaining purified RNA from low concentration cell medium. This Total RNA Extraction Droplet Array (TREDA) utilizes an array of surface-adhering droplets to facilitate the transportation of magnetic purification beads seamlessly through individual buffer solutions without solid structures. The fabrication of TREDA chips is rapid and does not require a microfabrication facility or expertise. The process takes less than 5 minutes. When purifying mRNA from bulk marine diatom samples, its repeatability and extraction efficiency are comparable to conventional tube-based operations. We demonstrate that TREDA can extract the total mRNA of about 10 marine diatom cells, indicating that the sensitivity of TREDA approaches single-digit cell numbers. PMID:25519439

  19. Magnetic Levitation.

    ERIC Educational Resources Information Center

    Rossing, Thomas D.; Hull, John R.

    1991-01-01

    Discusses the principles of magnetic levitation presented in the physics classroom and applied to transportation systems. Topics discussed include three classroom demonstrations to illustrate magnetic levitation, the concept of eddy currents, lift and drag forces on a moving magnet, magnetic levitation vehicles, levitation with permanent magnets…

  20. Magnetic Spinner

    ERIC Educational Resources Information Center

    Ouseph, P. J.

    2006-01-01

    A science toy sometimes called the "magnetic spinner" is an interesting class demonstration to illustrate the principles of magnetic levitation. It can also be used to demonstrate Faraday's law and a horizontally suspended physical pendulum. The levitated part contains two circular magnets encased in a plastic housing. Each magnet stays…

  1. Development of a micro nuclear magnetic resonance system

    NASA Astrophysics Data System (ADS)

    Goloshevsky, Artem

    Application of Nuclear Magnetic Resonance (NMR) to on-line/in-line control of industrial processes is currently limited by equipment costs and requirements for installation. A superconducting magnet generating strong fields is the most expensive part of a typical NMR instrument. In industrial environments, fringe magnetic fields make accommodation of NMR instruments difficult. However, a portable, low-cost and low-field magnetic resonance system can be used in virtually any environment. Development of a number of hardware components for a portable, low-cost NMR instrument is reported in this dissertation. Chapter one provides a discussion on a miniaturized Helmholtz spiral radio-frequency (RF) coil (average diameter equal to 3.5 mm) and an NMR probe built around a capillary (outer diameter = 1.59 mm and inner diameter = 1.02 mm) for flow imaging. Experiments of NMR spectroscopy, static and dynamic (flow) imaging, conducted with the use of the miniaturized coil, are described. Chapter two presents a microfabricated package of two biaxial gradient coils and a Helmholtz RF coil. Planar configuration of discrete wires was used to create magnetic field gradients. Performance of the microfabricated gradient coils while imaging water flow compared well with a commercial gradient set of much larger size. Chapter three reports on flow imaging experiments with power law fluids (aqueous solutions of sodium salt of carboxymethyl cellulose (CMC)) of different viscosities, carried out in the NMR probe with the miniaturized RF coil and capillary. Viscosities of the CMC solutions were determined based on the curve fits of the velocity profiles and simultaneous measurements of the flow rates. The curve fits were carried out according to the power law model equations. The NMR viscosity measurements compared well with measurements of the same CMC samples, performed on a conventional rotational rheometer. A portable, home-built transceiver, designed for NMR applications utilizing a

  2. Rapid magnetic microfluidic mixer utilizing AC electromagnetic field.

    PubMed

    Wen, Chih-Yung; Yeh, Cheng-Peng; Tsai, Chien-Hsiung; Fu, Lung-Ming

    2009-12-01

    This paper presents a novel simple micromixer based on stable water suspensions of magnetic nanoparticles (i.e. ferrofluids). The micromixer chip is built using standard microfabrication and simple soft lithography, and the design can be incorporated as a subsystem into any chemical microreactor or a miniaturized biological sensor. An electromagnet driven by an AC power source is used to induce transient interactive flows between a ferrofluid and Rhodamine B. The alternative magnetic field causes the ferrofluid to expand significantly and uniformly toward Rhodamine B, associated with a great number of extremely fine fingering structures on the interface in the upstream and downstream regions of the microchannel. These pronounced fingering patterns, which have not been observed by other active mixing methods utilizing only magnetic force, increase the mixing interfacial length dramatically. Along with the dominant diffusion effects occurring around the circumferential regions of the fine finger structures, the mixing efficiency increases significantly. The miscible fingering instabilities are observed and applied in the microfluidics for the first time. This work is carried with a view to developing functionalized ferrofluids that can be used as sensitive pathogen detectors and the present experimental results demonstrate that the proposed micromixer has excellent mixing capabilities. The mixing efficiency can be as high as 95% within 2.0 s and a distance of 3.0 mm from the inlet of the mixing channel, when the applied peak magnetic field is higher than 29.2 Oe and frequency ranges from 45 to 300 Hz. PMID:19921677

  3. Magnetic self-assembly of small parts

    NASA Astrophysics Data System (ADS)

    Shetye, Sheetal B.

    Modern society's propensity for miniaturized end-user products is compelling electronic manufacturers to assemble and package different micro-scale, multi-technology components in more efficient and cost-effective manners. As the size of the components gets smaller, issues such as part sticking and alignment precision create challenges that slow the throughput of conventional robotic pick-n-place systems. As an alternative, various self-assembly approaches have been proposed to manipulate micro to millimeter scale components in a parallel fashion without human or robotic intervention. In this dissertation, magnetic self-assembly (MSA) is demonstrated as a highly efficient, completely parallel process for assembly of millimeter scale components. MSA is achieved by integrating permanent micromagnets onto component bonding surfaces using wafer-level microfabrication processes. Embedded bonded powder methods are used for fabrication of the magnets. The magnets are then magnetized using pulse magnetization methods, and the wafers are then singulated to form individual components. When the components are randomly mixed together, self-assembly occurs when the intermagnetic forces overcome the mixing forces. Analytical and finite element methods (FEM) are used to study the force interactions between the micromagnets. The multifunctional aspects of MSA are presented through demonstration of part-to-part and part-to-substrate assembly of 1 mm x 1mm x 0.5 mm silicon components. Part-to-part assembly is demonstrated by batch assembly of free-floating parts in a liquid environment with the assembly yield of different magnetic patterns varying from 88% to 90% in 20 s. Part-to-substrate assembly is demonstrated by assembling an ordered array onto a fixed substrate in a dry environment with the assembly yield varying from 86% to 99%. In both cases, diverse magnetic shapes/patterns are used to control the alignment and angular orientation of the components. A mathematical model is

  4. Microfabrics in peridotites from the Baldissero, Balmuccia and Finero complexes in the Western Alps: High stress deformation and subsequent recrystallization at decaying stress

    NASA Astrophysics Data System (ADS)

    Matysiak, Agnes; Trepmann, Claudia

    2010-05-01

    The microfabrics of deformed peridotites from the Baldissero, Balmuccia and Finero complexes in the Western European Alps are investigated by optical and electron microscopic techniques (SEM/EBSD, TEM). The peridotites are mostly lherzolitic with 65-98% olivine, 5-30% orthopyroxene, 1-15% clinopyroxene and 1-2% spinel. Some samples from Balmuccia consist of olivine-websterites with 10-35% olivine, 15-50% orthopyroxene, 35-75% clinopyroxene and 1-2% spinel. Finero peridotites can contain minor amounts of hornblende and phlogopite. Samples from the Baldissero peridotite reveal evidence of significant brittle deformation by the common occurrence of transgranular shear zones. On the grain scale, olivine and pyroxene contain many microcracks and micro-shear zones. Olivine porphyroclasts show an intense undulatory extinction. Fine-grained recrystallized grains with a diameter of 10 µm to 15 µm are arranged along microcracks and micro-shear zones. Pyroxene porphyroclasts are twinned. Localized shear zones are also common in peridotites from Balmuccia. However, olivine and pyroxene show less intense brittle deformation. Recrystallized olivine grains with a diameter in the range of 20 µm to 50 µm occur mainly along grain boundaries of porphyroclasts but also along intragranular micro-shear zones. Olivine porphyroclasts show pronounced deformation lamellae, deformation bands and kink bands. Deformation lamellae and bands often developed parallel to (100). Deformation and kink bands in pyroxene porphyroclasts are parallel to (001). Some pyroxenes are mechanically twinned. Pyroxene recrystallized aggregates have a very fine grain size with a diameter varying between 2 µm to 25 µm. Samples from Finero show large elongate porphyroclasts with a long axis of up to 6 mm. Recrystallized grains have a diameter of up to 250 µm. Porphyroclasts as well as some of the recrystallized olivine grains show deformation bands and kink bands. Brittle deformation is restricted to

  5. Planetary magnetism

    NASA Technical Reports Server (NTRS)

    Russell, C. T.

    1981-01-01

    A synoptic view of early and recent data on the planetary magnetism of Mercury, Venus, the moon, Mars, Jupiter, and Saturn is presented. The data on Mercury from Mariner 10 are synthesized with various other sources, while data for Venus obtained from 120 orbits of Pioneer Venus give the upper limit of the magnetic dipole. Explorer 35 Lunar Orbiter data provided the first evidence of lunar magnetization, but it was the Apollo subsatellite data that measured accurately the magnetic dipole of the moon. A complete magnetic survey of Mars is still needed, and only some preliminary data are given on the magnetic dipole of the planet. Figures on the magnetic dipoles of Jupiter and Saturn are also suggested. It is concluded that if the magnetic field data are to be used to infer the interior properties of the planets, good measures of the multiple harmonics in the field are needed, which may be obtained only through low altitude polar orbits.

  6. Magnetizing of permanent magnets using HTS bulk magnets

    NASA Astrophysics Data System (ADS)

    Oka, Tetsuo; Muraya, Tomoki; Kawasaki, Nobutaka; Fukui, Satoshi; Ogawa, Jun; Sato, Takao; Terasawa, Toshihisa

    2012-01-01

    A demagnetized Nd-Fe-B permanent magnet was scanned just above the magnetic pole which contains the HTS bulk magnet generating a magnetic field of 3.27 T. The magnet sample was subsequently found to be fully magnetized in the open space of the static magnetic fields. We examined the magnetic field distributions when the magnetic poles were scanned twice to activate the magnet plate inversely with various overlap distances between the tracks of the bulk magnet. The magnetic field of the "rewritten" magnet reached the values of the magnetically saturated region of the material, showing steep gradients at the border of each magnetic pole. As a replacement for conventional pulse field magnetizing methods, this technique is proposed to expand the degree of freedom in the design of electromagnetic devices, and is proposed as a novel practical method for magnetizing rare-earth magnets, which have excellent magnetic performance and require intense fields of more than 3 T to be activated.

  7. Magnetic nanostructures.

    PubMed

    Bennemann, K

    2010-06-23

    Characteristic results of magnetism in small particles, thin films and tunnel junctions are presented. As a consequence of the reduced atomic coordination in small clusters and thin films the electronic states and density of states are modified. Thus, magnetic moments and magnetization are affected. Generally, in clusters and thin films magnetic anisotropy plays a special role. In tunnel junctions the interplay of magnetism, spin currents and superconductivity are of particular interest. In ring-like mesoscopic systems Aharonov-Bohm-induced currents are studied. Results are given for single transition metal clusters, cluster ensembles, thin films, mesoscopic structures and tunnel systems. PMID:21393778

  8. USING LIGA BASED MICROFABRICATION TO IMPROVE OVERALL HEAT TRANSFER EFFICIENCY OF PRESSURIZED WATER REACTOR: I. Effects of Different Micro Pattern on Overall Heat Transfer.

    SciTech Connect

    Zhang, M.; Ibekwe, S.; Li, G.; Pang, S.S.; and Lian, K.

    2006-07-01

    The Pressurized Water Reactors (PWRs in Figure 1) were originally developed for naval propulsion purposes, and then adapted to land-based applications. It has three parts: the reactor coolant system, the steam generator and the condenser. The Steam generator (a yellow area in Figure 1) is a shell and tube heat exchanger with high-pressure primary water passing through the tube side and lower pressure secondary feed water as well as steam passing through the shell side. Therefore, a key issue in increasing the efficiency of heat exchanger is to improve the design of steam generator, which is directly translated into economic benefits. The past research works show that the presence of a pin-fin array in a channel enhances the heat transfer significantly. Hence, using microfabrication techniques, such as LIGA, micro-molding or electroplating, some special microstructures can be fabricated around the tubes in the heat exchanger to increase the heat-exchanging efficiency and reduce the overall size of the heat-exchanger for the given heat transfer rates. In this paper, micro-pin fins of different densities made of SU-8 photoresist are fabricated and studied to evaluate overall heat transfer efficiency. The results show that there is an optimized micro pin-fin configuration that has the best overall heat transfer effects.

  9. Combining Bottom-Up Self-Assembly with Top-Down Microfabrication to Create Hierarchical Inverse Opals with High Structural Order.

    PubMed

    Schaffner, Manuel; England, Grant; Kolle, Mathias; Aizenberg, Joanna; Vogel, Nicolas

    2015-09-01

    Colloidal particles can assemble into ordered crystals, creating periodically structured materials at the nanoscale without relying on expensive equipment. The combination of small size and high order leads to strong interaction with visible light, which induces macroscopic, iridescent structural coloration. To increase the complexity and functionality, it is important to control the organization of such materials in hierarchical structures with high degrees of order spanning multiple length scales. Here, a bottom-up assembly of polystyrene particles in the presence of a silica sol-gel precursor material (tetraethylorthosilicate, TEOS), which creates crack-free inverse opal films with high positional order and uniform crystal alignment along the (110) crystal plane, is combined with top-down microfabrication techniques. Micrometer scale hierarchical superstructures having a highly regular internal nanostructure with precisely controlled crystal orientation and wall profiles are produced. The ability to combine structural order at the nano- and microscale enables the fabrication of materials with complex optical properties resulting from light-matter interactions at different length scales. As an example, a hierarchical diffraction grating, which combines Bragg reflection arising from the nanoscale periodicity of the inverse opal crystal with grating diffraction resulting from a micrometer scale periodicity, is demonstrated. PMID:26042571

  10. High-separation efficiency micro-fabricated multi-capillary gas chromatographic columns for simulants of the nerve agents and blister agents

    PubMed Central

    2014-01-01

    To achieve both high speed and separation efficiency in the separation of a mixture of nerve and blister agent simulants, a high-aspect-ratio micro-fabricated multi-capillary column (MCC, a 50-cm-long, 450-μm-deep, and 60-μm-wide four-capillary column) was fabricated by the application of the microelectromechanical system (MEMS) techniques. Mixtures of chemical warfare agent (CWA) simulants - dimethyl methylphosphonate (DMMP), triethyl phosphate (TEP), and methyl salicylate - were used as samples. The fabricated MCC allowed for the separation of all the components of the gaseous mixture within 24 s, even when the difference in boiling point was 4°C, as in the case of TEP and methyl salicylate. Furthermore, interfering agents - dichloromethane, ethanol, and toluene - were also included in the subsequent gaseous mixture samples. The boiling point of these six components ranged from 78°C to 219°C. All six components were clearly separated within 70 s. This study is the first to report the clear separation of gas mixtures of components with close boiling points. The column efficiency was experimentally determined to be 12,810 plates/m. PMID:24899869

  11. High-separation efficiency micro-fabricated multi-capillary gas chromatographic columns for simulants of the nerve agents and blister agents

    NASA Astrophysics Data System (ADS)

    Li, Yi; Du, Xiaosong; Wang, Yang; Tai, Huiling; Qiu, Dong; Lin, Qinghao; Jiang, Yadong

    2014-05-01

    To achieve both high speed and separation efficiency in the separation of a mixture of nerve and blister agent simulants, a high-aspect-ratio micro-fabricated multi-capillary column (MCC, a 50-cm-long, 450-μm-deep, and 60-μm-wide four-capillary column) was fabricated by the application of the microelectromechanical system (MEMS) techniques. Mixtures of chemical warfare agent (CWA) simulants - dimethyl methylphosphonate (DMMP), triethyl phosphate (TEP), and methyl salicylate - were used as samples. The fabricated MCC allowed for the separation of all the components of the gaseous mixture within 24 s, even when the difference in boiling point was 4°C, as in the case of TEP and methyl salicylate. Furthermore, interfering agents - dichloromethane, ethanol, and toluene - were also included in the subsequent gaseous mixture samples. The boiling point of these six components ranged from 78°C to 219°C. All six components were clearly separated within 70 s. This study is the first to report the clear separation of gas mixtures of components with close boiling points. The column efficiency was experimentally determined to be 12,810 plates/m.

  12. Specific sorting of single bacterial cells with microfabricated fluorescence-activated cell sorting and tyramide signal amplification fluorescence in situ hybridization.

    PubMed

    Chen, Chun H; Cho, Sung H; Chiang, Hsin-I; Tsai, Frank; Zhang, Kun; Lo, Yu-Hwa

    2011-10-01

    When attempting to probe the genetic makeup of diverse bacterial communities that elude cell culturing, researchers face two primary challenges: isolation of rare bacteria from microbial samples and removal of contaminating cell-free DNA. We report a compact, low-cost, and high-performance microfabricated fluorescence-activated cell sorting (μFACS) technology in combination with a tyramide signal amplification fluorescence in situ hybridization (TSA-FISH) to address these two challenges. The TSA-FISH protocol that was adapted for flow cytometry yields a 10-30-fold enhancement in fluorescence intensity over standard FISH methods. The μFACS technology, capable of enhancing its sensitivity by ~18 dB through signal processing, was able to enrich TSA-FISH-labeled E. coli cells by 223-fold. The μFACS technology was also used to remove contaminating cell-free DNA. After two rounds of sorting on E. coli mixed with λ-phage DNA (10 ng/μL), we demonstrated over 100,000-fold reduction in λ-DNA concentration. The integrated μFACS and TSA-FISH technologies provide a highly effective and low-cost solution for research on the genomic complexity of bacteria as well as single-cell genomic analysis of other sample types. PMID:21809842

  13. Microfabricated microporous membranes reduce the host immune response and prolong the functional lifetime of a closed-loop insulin delivery implant in a type 1 diabetic rat model.

    PubMed

    Li, Jason; Chu, Michael K L; Gordijo, Claudia R; Abbasi, Azhar Z; Chen, Kuan; Adissu, Hibret A; Löhn, Matthias; Giacca, Adria; Plettenburg, Oliver; Wu, Xiao Yu

    2015-04-01

    Implantation of a medical implant within the body inevitably triggers a host inflammatory response that negatively impacts its function and longevity. Nevertheless, the degree and severity of this response may be reduced by selecting appropriate materials, implant geometry, surface topography and surface treatment. Here we demonstrate a strategy to improve the biocompatibility of a chemically-driven closed-loop insulin delivery implant. A microfabricated microporous, poly(ethylene glycol)-grafted polydimethylsiloxane membrane was placed on top of the glucose-responsive insulin release plug of the implant. Implant biocompatibility was assessed in healthy rats while implant function was evaluated in a type 1 diabetic rat model. The microporous membrane with a small distance to the plug provided a geometric barrier to inflammatory cell migration and prevented leukocyte-mediated degradation of the plug for at least 30 days. Membrane-protected devices elicited a significantly milder inflammatory response and formation of a well-defined fibrous capsule at the device opening compared to unprotected devices. The device's glucose-responsiveness was nearly unchanged, although the insulin release rate decreased with decreasing pore size. The microporous membrane improved biocompatibility and prolonged in vivo efficacy of the implant by ∼3-fold. This work suggests the importance of implant design in modulating inflammatory response and thereby extending the functional duration of the implant. PMID:25682160

  14. Dielectrophoretic investigation of Bi2Te3 nanowires—a microfabricated thermoelectric characterization platform for measuring the thermoelectric and structural properties of single nanowires

    NASA Astrophysics Data System (ADS)

    Wang, Zhi; Kojda, Danny; Peranio, Nicola; Kroener, Michael; Mitdank, Rüdiger; Toellner, William; Nielsch, Kornelius; Fischer, Saskia F.; Gutsch, Sebastian; Zacharias, Margit; Eibl, Oliver; Woias, Peter

    2015-03-01

    In this article a microfabricated thermoelectric nanowire characterization platform to investigate the thermoelectric and structural properties of single nanowires is presented. By means of dielectrophoresis (DEP), a method to manipulate and orient nanowires in a controlled way to assemble them onto our measurement platform is introduced. The thermoelectric platform fabricated with optimally designed DEP electrodes results in a yield of nanowire assembly of approximately 90% under an applied peak-to-peak ac signal Vpp = 10 V and frequency f = 20 MHz within a series of 200 experiments. Ohmic contacts between the aligned single nanowire and the electrodes on the platform are established by electron beam-induced deposition. The Seebeck coefficient and electrical conductivity of electrochemically synthesized Bi2Te3 nanowires are measured to be -51 μV K-1 and (943 ± 160)/(Ω-1 cm-1), respectively. Chemical composition and crystallographic structure are obtained using transmission electron microscopy. The selected nanowire is observed to be single crystalline over its entire length and no grain boundaries are detected. At the surface of the nanowire, 66.1 ± 1.1 at.% Te and 34.9 ± 1.1 at.% Bi are observed. In contrast, chemical composition of 64.2 at.% Te and 35.8 at.% Bi is detected in the thick center of the nanowire.

  15. Fabrication and integration of permanent magnet materials into MEMS transducers

    NASA Astrophysics Data System (ADS)

    Wang, Naigang

    Microscale permanent magnets (PM) are a key building block for magnetically based microelectromechanical systems (MEMS), such as sensors, actuators, and energy converters. However, the inability to concurrently achieve good magnetic properties and an integrated magnet fabrication process hinders the development of magnetic MEMS. To address this need, this dissertation develops methods for wafer-level microfabrication of thick (10--500+ microm), high-performance, permanent magnets using low-temperature (<180 °C) process steps. These methods and materials are then used to demonstrate fully batch-fabricated magnetic MEMS transducers. Two methods to fabricate micromagnets are developed: electroplating of Co-rich Co-Pt magnets into photoresist-defined molds and micro-packing of rare-earth magnetic powders to form wax-bonded magnets embedded in silicon. Patterned micromagnets with excellent magnetic properties and process-flow compatibility are demonstrated. Electroplated Co-Pt micromagnets with thickness up to 10 microm exhibit out-of-plane anisotropy with coercivities and energy products of 330 kA/m and 69 kJ/m3, respectively. Wax-bonded Nd-Fe-B micromagnets (500 x 500 x 320 microm3) exhibit a coercivity of 737 kA/m and a maximum energy product of 17 kJ/m3 with isotopic behavior. The wax-bonded powder magnets are then integrated into MEMS fabrication processes to batch-fabricate various electrodynamic transducer prototypes. A cantilever-type microtransducer achieves a 2.7 microm vertical deflection at a driving current of 5.5 mArms at 100 Hz. A piston-type transducer with elastomeric membrane obtains a 2.2 microm vertical displacement at a driving current of 670 mArms at 200 Hz. These devices demonstrate the integrability of wax-bonded Nd-Fe-B powder magnets into microscale electromechanical transducers. Electromechanical lumped element models are then developed for the piston-type electrodynamic actuators. The models enable prediction of the device performance as an

  16. Development of Metallic Magnetic Calorimeters with a Critical Temperature Switch

    NASA Astrophysics Data System (ADS)

    Kim, S. R.; Choi, J.; Jo, H. S.; Kang, C. S.; Kim, G. B.; Kim, H. L.; Kim, I. W.; Lee, H. J.; Lee, J. H.; Lee, M. K.; Oh, S. Y.; Sala, E.; So, J. H.; Yoon, W. S.; Kim, Y. H.

    2016-07-01

    We report on the progress in the development of meander-shaped metallic magnetic calorimeters (MMCs) with a critical temperature switch. A niobium meander-shaped coil in an MMC is arranged to form a superconducting loop. It is to measure the change in magnetization and to apply a persistent current that magnetizes the MMC sensor material. In this work, part of the superconducting loop is fabricated with another superconducting material with its transition temperature (T_C) lower than that of niobium. A persistent current can be injected in the loop while reducing the temperature from above to below the T_C of the switch. Aluminum (Al) wires and an alloy of molybdenum and germanium (MoGe) were tested as critical temperature switch. The test with the Al switch demonstrated the temperature switch concept for meander-shaped MMCs that require a large field current. Microfabricated MoGe switches showed a T_C near 4.3 K, but only 7 mA of persistent current could be charged due to MoGe film discontinuity. This issue requires further improvement in the fabrication procedure.

  17. Toward Epileptic Brain Region Detection Based on Magnetic Nanoparticle Patterning

    PubMed Central

    Pedram, Maysam Z.; Shamloo, Amir; Alasty, Aria; Ghafar-Zadeh, Ebrahim

    2015-01-01

    Resection of the epilepsy foci is the best treatment for more than 15% of epileptic patients or 50% of patients who are refractory to all forms of medical treatment. Accurate mapping of the locations of epileptic neuronal networks can result in the complete resection of epileptic foci. Even though currently electroencephalography is the best technique for mapping the epileptic focus, it cannot define the boundary of epilepsy that accurately. Herein we put forward a new accurate brain mapping technique using superparamagnetic nanoparticles (SPMNs). The main hypothesis in this new approach is the creation of super-paramagnetic aggregates in the epileptic foci due to high electrical and magnetic activities. These aggregates may improve tissue contrast of magnetic resonance imaging (MRI) that results in improving the resection of epileptic foci. In this paper, we present the mathematical models before discussing the simulation results. Furthermore, we mimic the aggregation of SPMNs in a weak magnetic field using a low-cost microfabricated device. Based on these results, the SPMNs may play a crucial role in diagnostic epilepsy and the subsequent treatment of this disease. PMID:26402686

  18. Toward Epileptic Brain Region Detection Based on Magnetic Nanoparticle Patterning.

    PubMed

    Pedram, Maysam Z; Shamloo, Amir; Alasty, Aria; Ghafar-Zadeh, Ebrahim

    2015-01-01

    Resection of the epilepsy foci is the best treatment for more than 15% of epileptic patients or 50% of patients who are refractory to all forms of medical treatment. Accurate mapping of the locations of epileptic neuronal networks can result in the complete resection of epileptic foci. Even though currently electroencephalography is the best technique for mapping the epileptic focus, it cannot define the boundary of epilepsy that accurately. Herein we put forward a new accurate brain mapping technique using superparamagnetic nanoparticles (SPMNs). The main hypothesis in this new approach is the creation of super-paramagnetic aggregates in the epileptic foci due to high electrical and magnetic activities. These aggregates may improve tissue contrast of magnetic resonance imaging (MRI) that results in improving the resection of epileptic foci. In this paper, we present the mathematical models before discussing the simulation results. Furthermore, we mimic the aggregation of SPMNs in a weak magnetic field using a low-cost microfabricated device. Based on these results, the SPMNs may play a crucial role in diagnostic epilepsy and the subsequent treatment of this disease. PMID:26402686

  19. Magnetic investigations

    SciTech Connect

    Bath, G.D.; Jahren, C.E.; Rosenbaum, J.G.; Baldwin, M.J.

    1983-12-31

    Air and ground magnetic anomalies in the Climax stock area of the NTS help define the gross configuration of the stock and detailed configuration of magnetized rocks at the Boundary and Tippinip faults that border the stock. Magnetizations of geologic units were evaluated by measurements of magnetic properties of drill core, minimum estimates of magnetizations from ground magnetic anomalies for near surface rocks, and comparisons of measured anomalies with anomalies computed by a three-dimensional forward program. Alluvial deposits and most sedimentary rocks are nonmagnetic, but drill core measurements reveal large and irregular changes in magnetization for some quartzites and marbles. The magnetizations of quartz monzonite and granodiorite near the stock surface are weak, about 0.15 A/m, and increase at a rate of 0.00196 A/m/m to 1.55 A/m, at depths greater than 700 m (2300 ft). The volcanic rocks of the area are weakly magnetized. Aeromagnetic anomalies 850 m (2800 ft) above the stock are explained by a model consisting of five vertical prisms. Prisms 1, 2, and 3 represent the near surface outline of the stock, prism 4 is one of the models developed by Whitehill (1973), and prism 5 is modified from the model developed by Allingham and Zietz (1962). Most of the anomaly comes from unsampled and strongly-magnetized deep sources that could be either granite or metamorphosed sedimentary rocks. 48 refs., 23 figs., 3 tabs.

  20. A dual-axis pointing mirror with moving-magnet actuation

    NASA Astrophysics Data System (ADS)

    Ataman, Çağlar; Lani, Sébastien; Noell, Wilfried; de Rooij, Nico

    2013-02-01

    A large-aperture and large-angle MEMS-based 2D pointing mirror is presented. The device is electromagnetically actuated by a moving-magnet/stationary-coil pair and potentially suited for high power laser beam shaping and beam pointing applications, such as LIDAR. The 4×4 mm2 mirror, the radially symmetric compliant membrane, and the off-the-shelf permanent magnet are manually assembled, with the planar coil kept at a well-defined vertical distance from the permanent magnet by simple alignment pins. The mirror and the compliant membrane structures are separately microfabricated on bulk silicon and SOI wafers, respectively. The hybrid integration of microfabricated and off-the-shelf components enable low-risk/high-yield fabrication, while limiting the throughput. The device features minimum inter-axis cross coupling and good linearity and is highly immune to alignment and assembly imperfections, thanks to the robust actuation principle. All the components including the bi-axial electromagnetic actuator provide a device footprint as small as the top mirror, allowing the design to be used in compact and high-fill-factor mirror arrays. With a drive coil of 400 mA and 5.12 W drive power, the total uniaxial dc rotation exceeds ±16° (optical) for both axes with good decoupling. At maximum measured angle (biaxial 10° (mechanical)), a position stability better than 0.05° over 7 h, and a position repeatability of 0.04° over 5000 switching cycles is reported. Thermally, the simulated mirror temperature increases to 64 K above the heat sink temperature with a thermal in-flux of 1 kW m-2, under absolute vacuum.

  1. Planetary Magnetism

    NASA Technical Reports Server (NTRS)

    Connerney, J. E. P.

    2007-01-01

    The chapter on Planetary Magnetism by Connerney describes the magnetic fields of the planets, from Mercury to Neptune, including the large satellites (Moon, Ganymede) that have or once had active dynamos. The chapter describes the spacecraft missions and observations that, along with select remote observations, form the basis of our knowledge of planetary magnetic fields. Connerney describes the methods of analysis used to characterize planetary magnetic fields, and the models used to represent the main field (due to dynamo action in the planet's interior) and/or remnant magnetic fields locked in the planet's crust, where appropriate. These observations provide valuable insights into dynamo generation of magnetic fields, the structure and composition of planetary interiors, and the evolution of planets.

  2. Magnetic nanocomposites.

    PubMed

    Behrens, Silke; Appel, Ingo

    2016-06-01

    Magnetic nanocomposites are multi-component materials, typically containing nanosized magnetic materials to trigger the response to an external stimulus (i.e., an external static or alternating magnetic field). Up to now, the search for novel nanocomposites has lead to the combination of a plethora of different materials (e.g., gels, liquid crystals, renewable polymers, silica, carbon or metal organic frameworks) with various types of magnetic particles, offering exciting perspectives not only for fundamental investigations but also for application in various fields, including medical therapy and diagnosis, separations, actuation, or catalysis. In this review, we have selected a few of the most recent examples to highlight general concepts and advances in the preparation of magnetic nanocomposites and recent advances in the synthesis of magnetic nanoparticles. PMID:26938504

  3. Magnetic Imaging

    NASA Astrophysics Data System (ADS)

    Petford-Long, A. K.

    Spin-transport effects, such as giant magnetoresistance, rely on the fact that there is a difference in scattering between the spin-up and spin-down electrons in a ferromagnetic material. The degree to which each electron channel is scattered depends on the magnetisation direction within the material, and thus on the local magnetic domain structure. It is therefore of importance when analysing spin-transport devices to understand their magnetic domain structure, both as a bulk property and locally. The aim of this chapter is to review a number of the techniques currently used to image magnetic domain structure in materials. Although a considerable amount of information about the magnetic properties and behaviour of a piece of material, for example a thin ferromagnetic film, can be obtained from bulk magnetometry measurements, it is often extremely useful to image the magnetic domain structure of the film and thus gain information about its magnetic properties at a local level. The various magnetic imaging techniques yet to be described can be extended, by the application of in-situ magnetic fields which allow not only the magnetic domains but also the magnetisation reversal process to be followed in real-time.

  4. Magnetic shielding

    DOEpatents

    Kerns, J.A.; Stone, R.R.; Fabyan, J.

    1987-10-06

    A magnetically-conductive filler material bridges the gap between a multi-part magnetic shield structure which substantially encloses a predetermined volume so as to minimize the ingress or egress of magnetic fields with respect to that volume. The filler material includes a heavy concentration of single-magnetic-domain-sized particles of a magnetically conductive material (e.g. soft iron, carbon steel or the like) dispersed throughout a carrier material which is generally a non-magnetic material that is at least sometimes in a plastic or liquid state. The maximum cross-sectional particle dimension is substantially less than the nominal dimension of the gap to be filled. An epoxy base material (i.e. without any hardening additive) low volatility vacuum greases or the like may be used for the carrier material. The structure is preferably exposed to the expected ambient magnetic field while the carrier is in a plastic or liquid state so as to facilitate alignment of the single-magnetic-domain-sized particles with the expected magnetic field lines. 3 figs.

  5. Magnetic shielding

    DOEpatents

    Kerns, John A.; Stone, Roger R.; Fabyan, Joseph

    1987-01-01

    A magnetically-conductive filler material bridges the gap between a multi-part magnetic shield structure which substantially encloses a predetermined volume so as to minimize the ingress or egress of magnetic fields with respect to that volume. The filler material includes a heavy concentration of single-magnetic-domain-sized particles of a magnetically conductive material (e.g. soft iron, carbon steel or the like) dispersed throughout a carrier material which is generally a non-magnetic material that is at least sometimes in a plastic or liquid state. The maximum cross-sectional particle dimension is substantially less than the nominal dimension of the gap to be filled. An epoxy base material (i.e. without any hardening additive) low volatility vacuum greases or the like may be used for the carrier material. The structure is preferably exposed to the expected ambient magnetic field while the carrier is in a plastic or liquid state so as to facilitate alignment of the single-magnetic-domain-sized particles with the expected magnetic field lines.

  6. Planetary magnetism

    NASA Technical Reports Server (NTRS)

    Russell, C. T.

    1980-01-01

    Planetary spacecraft have now probed the magnetic fields of all the terrestrial planets, the moon, Jupiter, and Saturn. These measurements reveal that dynamos are active in at least four of the planets, Mercury, the earth, Jupiter, and Saturn but that Venus and Mars appear to have at most only very weak planetary magnetic fields. The moon may have once possessed an internal dynamo, for the surface rocks are magnetized. The large satellites of the outer solar system are candidates for dynamo action in addition to the large planets themselves. Of these satellites the one most likely to generate its own internal magnetic field is Io.

  7. Synthesis of novel fluorene-based two-photon absorbing molecules and their applications in optical data storage, microfabrication, and stimulated emission depletion

    NASA Astrophysics Data System (ADS)

    Yanez, Ciceron

    2009-12-01

    Two-photon absorption (2PA) has been used for a number of scientific and technological applications, exploiting the fact that the 2PA probability is directly proportional to the square of the incident light intensity (while one-photon absorption bears a linear relation to the incident light intensity). This intrinsic property of 2PA leads to 3D spatial localization, important in fields such as optical data storage, fluorescence microscopy, and 3D microfabrication. The spatial confinement that 2PA enables has been used to induce photochemical and photophysical events in increasingly smaller volumes and allowed nonlinear, 2PA-based, technologies to reach sub-diffraction limit resolutions. The primary focus of this dissertation is the development of novel, efficient 2PA, fluorene-based molecules to be used either as photoacid generators (PAGs) or fluorophores. A second aim is to develop more effective methods of synthesizing these compounds. As a third and final objective, the new molecules were used to develop a write-once-read many (WORM) optical data storage system, and stimulated emission depletion probes for bioimaging. In Chapter I, the microwave-assisted synthesis of triarylsulfonium salt photoacid generators (PAGs) from their diphenyliodonium counterparts is reported. The microwave-assisted synthesis of these novel sulfonium salts afforded reaction times 90 to 420 times faster than conventional thermal conditions, with photoacid quantum yields of new sulfonium PAGs ranging from 0.01 to 0.4. These PAGs were used to develop a fluorescence readout-based, nonlinear three-dimensional (3D) optical data storage system (Chapter II). In this system, writing was achieved by acid generation upon two-photon absorption (2PA) of a PAG (at 710 or 730 nm). Readout was then performed by interrogating two-photon absorbing dyes, after protonation, at 860 nm. Two-photon recording and readout of voxels was demonstrated in five and eight consecutive, crosstalk-free layers within a

  8. Microfabricated optical fiber with microlens that produces large field-of-view video-rate optical beam scanning for microendoscopy applications

    NASA Astrophysics Data System (ADS)

    Seibel, Eric J.; Fauver, Mark; Crossman-Bosworth, Janet L.; Smithwick, Quinn Y. J.; Brown, Chris M.

    2003-07-01

    Our goal is to produce a micro-optical scanner at the tip of an ultrathin flexible endoscope with an overall diameter of 1 mm. Using a small diameter piezoelectric tube actuator, a cantilevered optical fiber can be driven in mechanical resonance to scan a beam of light in a space-filling, spiral scan pattern. By knowing and/or controlling the fiber position and acquiring backscattered intensity with a photodetector, an image is acquired. A microfabrication process of computer-controlled acid etching is used to reduce the mass along the fiber scanner shaft to allow for high scan amplitude and frequency. A microlens (<1 mm diameter) is fabricated on the end of the optical fiber to reduce divergence of the scanned optical beam. This added mass of the microlens at the free end of the fiber causes the location of the second vibratory node to shift to near the focal length of the microlens. The result is a microlens undergoing angular rotation along two axes with minimal lateral microlens displacement. Preliminary experimental results indicate that this method of optical beam scanning can deliver laser energy over wide fields of view (>50 degrees full angle), up to video scan rates (>10 KHz), while maintaining a scanner diameter of 1 mm. A comparison can be made to bi-axial mirror scanners being fabricated as a MEMS device (micro-electro-mechanical system). Based on the opto-mechanical performance of these microlensed fiber scanners, flexible catheter scopes are possible for new microendoscopies that combine imaging with laser diagnoses.

  9. A microfabricated, low dark current a-Se detector for measurement of microplasma optical emission in the UV for possible use on-site

    NASA Astrophysics Data System (ADS)

    Abbaszadeh, Shiva; Karim, Karim S.; Karanassios, Vassili

    2013-05-01

    Traditionally, samples are collected on-site (i.e., in the field) and are shipped to a lab for chemical analysis. An alternative is offered by using portable chemical analysis instruments that can be used on-site (i.e., in the field). Many analytical measurements by optical emission spectrometry require use of light-sources and of spectral lines that are in the Ultra-Violet (UV, ~200 nm - 400 nm wavelength) region of the spectrum. For such measurements, a portable, battery-operated, fiber-optic spectrometer equipped with an un-cooled, linear, solid-state detector may be used. To take full advantage of the advanced measurement capabilities offered by state-of-the-art solid-state detectors, cooling of the detector is required. But cooling and other thermal management hamper portability and use on-site because they add size and weight and they increase electrical power requirements. To address these considerations, an alternative was implemented, as described here. Specifically, a microfabricated solid-state detector for measurement of UV photons will be described. Unlike solid-state detectors developed on crystalline Silicon, this miniaturized and low-cost detector utilizes amorphous Selenium (a-Se) as its photosensitive material. Due to its low dark current, this detector does not require cooling, thus it is better suited for portable use and for chemical measurements on-site. In this paper, a microplasma will be used as a light-source of UV photons for the a-Se detector. For example, spectra acquired using a microplasma as a light-source will be compared with those obtained with a portable, fiber-optic spectrometer equipped with a Si-based 2080-element detector. And, analytical performance obtained by introducing ng-amounts of analytes into the microplasma will be described.

  10. Electrochemical and microfabrication strategies for remotely operated smart chemical sensors: application of anodic stripping coulometry to calibration-free measurements of copper and mercury.

    PubMed

    Marei, Mohamed M; Roussel, Thomas J; Keynton, Robert S; Baldwin, Richard P

    2013-11-25

    Remote unattended sensor networks are increasingly sought after to monitor the drinking water distribution grid, industrial wastewater effluents, and even rivers and lakes. One of the biggest challenges for application of such sensors is the issue of in-field device calibration. With this challenge in mind, we report here the use of anodic stripping coulometry (ASC) as the basis of a calibration-free micro-fabricated electrochemical sensor (CF-MES) for heavy metal determinations. The sensor platform consisted of a photo-lithographically patterned gold working electrode on SiO2 substrate, which was housed within a custom stopped-flow thin-layer cell, with a total volume of 2-4 μL. The behavior of this platform was characterized by fluorescent particle microscopy and electrochemical studies utilizing Fe(CN)6(3-/4-) as a model analyte. The average charge obtained for oxidation of 500 μM ferrocyanide after 60s over a 10 month period was 176 μC, corresponding to a volume of 3.65 μL (RSD = 2.4%). The response of the platform to copper concentrations ranging from 50 to 7500 ppb was evaluated, and the ASC results showed a linear dependence of charge on copper concentrations with excellent reproducibility (RSD ≤ 2.5%) and accuracy for most concentrations (≤ 5-10% error). The platform was also used to determine copper and mercury mixtures, where the total metallic content was measurable with excellent reproducibility (RSD ≤ 4%) and accuracy (≤ 6% error). PMID:24216196

  11. Magnetic shielding

    DOEpatents

    Kerns, J.A.; Stone, R.R.; Fabyan, J.

    1985-02-12

    A magnetically-conductive filler material bridges the gap between a multi-part magnetic shield structure which substantially encloses a predetermined volume so as to minimize the ingress or egress of magnetic fields with respect to that volume. The filler material includes a heavy concentration of single-magnetic-domain-sized particles of a magnetically conductive material (e.g. soft iron, carbon steel or the like) dispersed throughout a carrier material which is generally a non-magnetic material that is at least sometimes in a plastic or liquid state. The maximum cross-sectional particle dimension is substantially less than the nominal dimension of the gap to be filled. An epoxy base material (i.e. without any hardening additive) low volatility vacuum greases or the like may be used for the carrier material. The structure is preferably exposed to the expected ambient field while the carrier is in a plastic or liquid state so as to facilitate alignment of the single-magnetic-domain-sized particles with the expected magnetic field lines.

  12. Magnetic Recording.

    ERIC Educational Resources Information Center

    Lowman, Charles E.

    A guide to the technology of magnetic recorders used in such fields as audio recording, broadcast and closed-circuit television, instrumentation recording, and computer data systems is presented. Included are discussions of applications, advantages, and limitations of magnetic recording, its basic principles and theory of operation, and its…

  13. Magnet Healing?

    NASA Astrophysics Data System (ADS)

    Finegold, Leonard

    2000-03-01

    Many people are convinced that static magnets—applied to their skin—will heal ills, and many businesses sell such magnets. The biophysics of such healing was reviewed [1] together with the general biophysics of static fields. Birds and insects do use the earth’s magnetic field for navigation. While insect and frog egg development can clearly be influenced by high fields (7 T and 17 T respectively), there is no experimental evidence that small magnetic fields (of less than 0.5 T) might heal, and much evidence that they cannot heal. A puzzle to the physics community is: How to show laypersons that simple magnets (very probably) do not heal, however attractive that idea might be. [1] L. Finegold, The Physics of "Alternative Medicine": Magnet Therapy, The Scientific Review of Alternative Medicine 3:26-33 (1999).

  14. Magnetic nanotubes

    DOEpatents

    Matsui, Hiroshi; Matsunaga, Tadashi

    2010-11-16

    A magnetic nanotube includes bacterial magnetic nanocrystals contacted onto a nanotube which absorbs the nanocrystals. The nanocrystals are contacted on at least one surface of the nanotube. A method of fabricating a magnetic nanotube includes synthesizing the bacterial magnetic nanocrystals, which have an outer layer of proteins. A nanotube provided is capable of absorbing the nanocrystals and contacting the nanotube with the nanocrystals. The nanotube is preferably a peptide bolaamphiphile. A nanotube solution and a nanocrystal solution including a buffer and a concentration of nanocrystals are mixed. The concentration of nanocrystals is optimized, resulting in a nanocrystal to nanotube ratio for which bacterial magnetic nanocrystals are immobilized on at least one surface of the nanotubes. The ratio controls whether the nanocrystals bind only to the interior or to the exterior surfaces of the nanotubes. Uses include cell manipulation and separation, biological assay, enzyme recovery, and biosensors.

  15. Miniaturized Nuclear Magnetic Resonance Platform for Detection and Profiling of Circulating Tumor Cells

    PubMed Central

    Castro, Cesar M.; Ghazani, Arezou A.; Chung, Jaehoon; Shao, Huilin; Issadore, David; Yoon, Tae-Jong; Weissleder, Ralph; Lee, Hakho

    2013-01-01

    Accurate detection and profiling of circulating tumor cells (CTCs) is a highly sought after technology to improve cancer management. Such “liquid biopsies” could offer a non-invasive, repeatable window into each patient’s tumor, facilitating early cancer diagnosis and treatment monitoring. The rarity of CTCs, approximated at 1 CTC for every billion peripheral blood cells, however, poses significant challenges to sensitive and reliable detection. We have recently developed a new biosensor platform, namely a micro-nuclear magnetic resonance (µNMR). Through the synergistic integration of microfabrication, nanosensors, and novel chemistries, the µNMR platform offers high detection sensitivity and point-of-care operation, overcoming technical barriers in CTC research. We herein review the µNMR technology with emphasis on its application on CTC detection. Recent advances in the sensing technology will be summarized, followed by the description on the dynamic interplay between preclinical and clinical CTC studies. PMID:23835814

  16. Development of cryogenic alpha spectrometers using metallic magnetic calorimeters

    NASA Astrophysics Data System (ADS)

    Ranitzsch, P. C.; Kempf, S.; Pabinger, A.; Pies, C.; Porst, J.-P.; Schäfer, S.; Fleischmann, A.; Gastaldo, L.; Enss, C.; Jang, Y. S.; Kim, I. H.; Kim, M. S.; Kim, Y. H.; Lee, J. S.; Lee, K. B.; Lee, M. K.; Lee, S. J.; Yoon, W. S.; Yuryev, Y. N.

    2011-10-01

    Cryogenic particle detectors have recently been adopted in radiation detection and measurement because of their high energy resolution. Many of these detectors have demonstrated energy resolutions better than the theoretical limit of semiconductor detectors. We report the development of a micro-fabricated magnetic calorimeter coupled to a large-area particle absorber. It is based on a planar, 1 mm 2 large paramagnetic temperature sensor made of sputtered Au:Er, which covers a superconducting meander-shaped pickup coil coupled to a low-noise dc-SQUID to monitor the magnetization of the sensor. A piece of gold foil of 2.5×2.5×0.07 mm 3 was glued to the Au:Er film to serve as an absorber for incident alpha particles. The detector performance was investigated with an 241Am source. The signal size comparison for alpha and gamma peaks with a large difference in energy demonstrated that the detector had good linear behavior. An energy resolution of 2.83±0.05 keV in FWHM was obtained for 5.5 MeV alpha particles.

  17. Magnetic Nickel iron Electroformed Trap (MagNET): a master/replica fabrication strategy for ultra-high throughput (>100 mL h(-1)) immunomagnetic sorting.

    PubMed

    Ko, Jina; Yelleswarapu, Venkata; Singh, Anup; Shah, Nishal; Issadore, David

    2016-08-01

    Microfluidic devices can sort immunomagnetically labeled cells with sensitivity and specificity much greater than that of conventional methods, primarily because the size of microfluidic channels and micro-scale magnets can be matched to that of individual cells. However, these small feature sizes come at the expense of limited throughput (ϕ < 5 mL h(-1)) and susceptibility to clogging, which have hindered current microfluidic technology from processing relevant volumes of clinical samples, e.g. V > 10 mL whole blood. Here, we report a new approach to micromagnetic sorting that can achieve highly specific cell separation in unprocessed complex samples at a throughput (ϕ > 100 mL h(-1)) 100× greater than that of conventional microfluidics. To achieve this goal, we have devised a new approach to micromagnetic sorting, the magnetic nickel iron electroformed trap (MagNET), which enables high flow rates by having millions of micromagnetic traps operate in parallel. Our design rotates the conventional microfluidic approach by 90° to form magnetic traps at the edges of pores instead of in channels, enabling millions of the magnetic traps to be incorporated into a centimeter sized device. Unlike previous work, where magnetic structures were defined using conventional microfabrication, we take inspiration from soft lithography and create a master from which many replica electroformed magnetic micropore devices can be economically manufactured. These free-standing 12 μm thick permalloy (Ni80Fe20) films contain micropores of arbitrary shape and position, allowing the device to be tailored for maximal capture efficiency and throughput. We demonstrate MagNET's capabilities by fabricating devices with both circular and rectangular pores and use these devices to rapidly (ϕ = 180 mL h(-1)) and specifically sort rare tumor cells from white blood cells. PMID:27170379

  18. Magnetic disk

    NASA Technical Reports Server (NTRS)

    Mallinson, John C.

    1991-01-01

    Magnetic disk recording was invented in 1953 and has undergone intensive development ever since. As a result of this 38 years of development, the cost per byte and the areal density has halved and doubled, respectively every 2 to 2 1/2 years. Today, the cost per byte is lower than 10(exp -6) dollars per byte and area densities exceed 100 x 10(exp 6) bits per square inch. The recent achievements in magnetic disk recording will first be surveyed briefly. Then the principal areas of current technical development will be outlined. Finally, some comments will be made about the future of magnetic disk recording.

  19. Lunar magnetism

    NASA Technical Reports Server (NTRS)

    Hood, L. L.; Sonett, C. P.; Srnka, L. J.

    1984-01-01

    Aspects of lunar paleomagnetic and electromagnetic sounding results which appear inconsistent with the hypothesis that an ancient core dynamo was the dominant source of the observed crustal magnetism are discussed. Evidence is summarized involving a correlation between observed magnetic anomalies and ejecta blankets from impact events which indicates the possible importance of local mechanisms involving meteoroid impact processes in generating strong magnetic fields at the lunar surface. A reply is given to the latter argument which also presents recent evidence of a lunar iron core.

  20. Magnetic Bearing

    NASA Technical Reports Server (NTRS)

    1996-01-01

    AVCON, Inc. produces advanced magnetic bearing systems for industrial use, offering a unique technological approach based on contract work done at Marshall Space Flight Center and Lewis Research Center. Designed for the turbopump of the Space Shuttle main engine, they are now used in applications such as electric power generation, petroleum refining, machine tool operation and natural gas pipelines. Magnetic bearings support moving machinery without physical contact; AVCON's homopolar approach is a hybrid of permanent and electromagnets which are one-third the weight, smaller and more power- efficient than previous magnetic bearings.

  1. Magnetic Bacteria.

    ERIC Educational Resources Information Center

    Nelson, Jane Bray; Nelson, Jim

    1992-01-01

    Describes the history of Richard Blakemore's discovery of magnetotaxic organisms. Discusses possible reasons why the magnetic response in bacteria developed. Proposes research experiments integrating biology and physics in which students investigate problems using cultures of magnetotaxic organisms. (MDH)

  2. CRYOGENIC MAGNETS

    DOEpatents

    Post, R.F.; Taylor, C.E.

    1963-05-21

    A cryogenic magnet coil is described for generating magnetic fields of the order of 100,000 gauss with a minimum expenditure of energy lost in resistive heating of the coil inductors and energy lost irreversibly in running the coil refrigeration plant. The cryogenic coil comprises a coil conductor for generating a magnetic field upon energization with electrical current, and refrigeration means disposed in heat conductive relation to the coil conductor for cooling to a low temperature. A substantial reduction in the power requirements for generating these magnetic fields is attained by scaling the field generating coil to large size and particular dimensions for a particular conductor, and operating the coil at a particular optimum temperature commensurate with minimum overall power requirements. (AEC)

  3. Superconducting magnets

    SciTech Connect

    Willen, E.; Dahl, P.; Herrera, J.

    1985-01-01

    This report provides a self-consistent description of a magnetic field in the aperture of a superconducting magnet and details how this field can be calculated in a magnet with cos theta current distribution in the coils. A description of an apparatus that can be used to measure the field uniformity in the aperture has been given. Finally, a detailed description of the magnet being developed for use in the Superconducting Super Collider is given. When this machine is built, it will be by far the largest application of superconductivity to date and promises to make possible the experimental discoveries needed to understand the basic laws of nature governing the world in which we live.

  4. Magnetic monopoles

    SciTech Connect

    Preskill, J

    1984-01-01

    This article offers a review of the physics of the magnetic monopole, which, although as yet unseen, offers sound theoretical reasons to believe that it must exist. Several theories are presented and equations are given. The idea that magnetic monopoles, stable particles carrying magnetic charges, ought to exist has, according to the authors, proved to be very durable. One theory presented demonstrates the consistency of magnetic monopoles with quantum electrodynamics. Another theory demonstrates the necessity of monopoles in grand unified gauge theories. The authors believe it is reasonable to expect the monopole to be an extremely heavy stable elementary particle. The stability of the classical monopole solution given is ensured by a topological principle explained.

  5. Magnetic monopoles

    SciTech Connect

    Fryberger, D.

    1984-12-01

    In this talk on magnetic monopoles, first the author briefly reviews some historical background; then, the author describes what several different types of monopoles might look like; and finally the author discusses the experimental situation. 81 references.

  6. Magnetic Reconnection

    NASA Video Gallery

    This science visualization shows a magnetospheric substorm, during which, magnetic reconnection causes energy to be rapidly released along the field lines in the magnetotail, that part of the magne...

  7. Superconducting magnet

    NASA Technical Reports Server (NTRS)

    1985-01-01

    Extensive computer based engineering design effort resulted in optimization of a superconducting magnet design with an average bulk current density of approximately 12KA/cm(2). Twisted, stranded 0.0045 inch diameter NbTi superconductor in a copper matrix was selected. Winding the coil from this bundle facilitated uniform winding of the small diameter wire. Test coils were wound using a first lot of the wire. The actual packing density was measured from these. Interwinding voltage break down tests on the test coils indicated the need for adjustment of the wire insulation on the lot of wire subsequently ordered for construction of the delivered superconducting magnet. Using the actual packing densities from the test coils, a final magnet design, with the required enhancement and field profile, was generated. All mechanical and thermal design parameters were then also fixed. The superconducting magnet was then fabricated and tested. The first test was made with the magnet immersed in liquid helium at 4.2K. The second test was conducted at 2K in vacuum. In the latter test, the magnet was conduction cooled from the mounting flange end.

  8. MAGNETIC IMAGING OF NANOCOMPOSITE MAGNETS

    SciTech Connect

    VOLKOV,V.V.ZHU,Y.

    2003-08-03

    Understanding the structure and magnetic behavior is crucial for optimization of nanocomposite magnets with high magnetic energy products. Many contributing factors such as phase composition, grain size distribution and specific domain configurations reflect a fine balance of magnetic energies at nanometer scale. For instance, magnetocrystalline anisotropy of grains and their orientations, degree of exchange coupling of magnetically soft and hard phases and specific energy of domain walls in a material. Modern microscopy, including Lorentz microscopy, is powerful tool for visualization and microstructure studies of nanocomposite magnets. However, direct interpretation of magnetically sensitive Fresnel/Foucault images for nanomagnets is usually problematic, if not impossible, because of the complex image contrast due to small grain size and sophisticated domain structure. Recently we developed an imaging technique based on Lorentz phase microscopy [l-4], which allows bypassing many of these problems and get quantitative information through magnetic flux mapping at nanometer scale resolution with a magnetically calibrated TEM [5]. This is our first report on application of this technique to nanocomposite magnets. In the present study we examine a nanocomposite magnet of nominal composition Nd{sub 2}Fe{sub 14+{delta}}B{sub 1.45} (14+{delta}=23.3, i.e. ''hard'' Nd{sub 2}Fe{sub 14}B-phase and 47.8 wt% of ''soft'' {alpha}-Fe phase ({delta}=9.3)), produced by Magnequench International, Inc. Conventional TEM/HREM study (Fig. 1-2) suggests that material has a bimodal grain-size distribution with maximum at d{sub max}=25 nm for Nd{sub 2}Fe{sub 14}B phase and d{sub max} = 15 nm for {alpha}-Fe phase (Fig.1c, Fig.2) in agreement with synchrotron X-ray studies (d{sub max}=23.5 nm for Nd{sub 2}Fe{sub 14}B [6]). Lattice parameters for Nd{sub 2}Fe{sub 14}B phase are a=8.80 and c=12.2 {angstrom}, as derived from SAED ring patterns (Fig.1a), again in good agreement with X-ray data

  9. Microfabrication with femtosecond laser processing : (A) laser ablation of ferrous alloys, (B) direct-write embedded optical waveguides and integrated optics in bulk glasses.

    SciTech Connect

    Guo, Junpeng; McDaniel, Karen Lynn; Palmer, Jeremy Andrew; Yang, Pin; Griffith, Michelle Lynn; Vawter, Gregory Allen; Harris, Marc F.; Tallant, David Robert; Luk, Ting Shan; Burns, George Robert

    2004-11-01

    At Sandia National Laboratories, miniaturization dominates future hardware designs, and technologies that address the manufacture of micro-scale to nano-scale features are in demand. Currently, Sandia is developing technologies such as photolithography/etching (e.g. silicon MEMS), LIGA, micro-electro-discharge machining (micro-EDM), and focused ion beam (FIB) machining to fulfill some of the component design requirements. Some processes are more encompassing than others, but each process has its niche, where all performance characteristics cannot be met by one technology. For example, micro-EDM creates highly accurate micro-scale features but the choice of materials is limited to conductive materials. With silicon-based MEMS technology, highly accurate nano-scale integrated devices are fabricated but the mechanical performance may not meet the requirements. Femtosecond laser processing has the potential to fulfill a broad range of design demands, both in terms of feature resolution and material choices, thereby improving fabrication of micro-components. One of the unique features of femtosecond lasers is the ability to ablate nearly all materials with little heat transfer, and therefore melting or damage, to the surrounding material, resulting in highly accurate micro-scale features. Another unique aspect to femtosecond radiation is the ability to create localized structural changes thought nonlinear absorption processes. By scanning the focal point within transparent material, we can create three-dimensional waveguides for biological sensors and optical components. In this report, we utilized the special characteristics of femtosecond laser processing for microfabrication. Special emphasis was placed on the laser-material interactions to gain a science-based understanding of the process and to determine the process parameter space for laser processing of metals and glasses. Two areas were investigated, including laser ablation of ferrous alloys and direct

  10. Note: On-chip multifunctional fluorescent-magnetic Janus helical microswimmers.

    PubMed

    Hwang, G; Decanini, D; Leroy, L; Haghiri-Gosnet, A M

    2016-03-01

    Microswimmers integrated into microfluidic devices that are capable of self-illumination through fluorescence could revolutionize many aspects of technology, especially for biological applications. Few illumination and propulsion techniques of helical microswimmers inside microfluidic channels have been demonstrated. This paper presents the fabrication, detachment, and magnetic propulsions of multifunctional fluorescent-magnetic helical microswimmers integrated inside microfluidics. The fabrication process is based on two-photon laser lithography to pattern 3-D nanostructures from fluorescent photoresist coupled with conventional microfabrication techniques for magnetic thin film deposition by shadowing. After direct integration inside a microfluidic device, injected gas bubble allows gentle detachment of the integrated helical microswimmers whose magnetic propulsion can then be directly applied inside the microfluidic channel using external electromagnetic coil setup. With their small scale, fluorescence, excellent resistance to liquid/gas surface tension, and robust propulsion capability inside the microfluidic channel, the microswimmers can be used as high-resolution and large-range mobile micromanipulators inside microfluidic channels. PMID:27036837

  11. Magnetic direction.

    PubMed

    Duchene, Pam; Muhm, John B

    2005-01-01

    In April 2005, the American Nurses Association (ANA) awarded St. Joseph Hospital, Nashua, NH, its highest honor for excellence in nursing: "Magnet Recognition." The Magnet Recognition Program was developed by the ANA's American Nurses Credentialing Center in the early 1980s to recognize health care organizations that provide the best in nursing care and uphold the tradition of excellence in professional nursing practice. St. Joseph began pursuing Magnet status more than three years ago, starting with a number of enhancements to nursing practices. The hospital worked hard to improve nurse-to-patient staffing and included many of its nurses on the nursing quality council, division advisory, and cultural diversity committees. Magnet program appraisers visited the hospital this January to conduct an intensive, on-site three-day examination. They interviewed patients, staff nurses, physicians, hospital employees, administrators, board members, and nursing leadership to evaluate St. Joseph's nursing care, services, and delivery of care to patients and their families. Soon after, Magnet status was bestowed. PMID:16350902

  12. MAGNETIC GRID

    DOEpatents

    Post, R.F.

    1960-08-01

    An electronic grid is designed employing magnetic forces for controlling the passage of charged particles. The grid is particularly applicable to use in gas-filled tubes such as ignitrons. thyratrons, etc., since the magnetic grid action is impartial to the polarity of the charged particles and, accordingly. the sheath effects encountered with electrostatic grids are not present. The grid comprises a conductor having sections spaced apart and extending in substantially opposite directions in the same plane, the ends of the conductor being adapted for connection to a current source.

  13. Magnetic particles

    NASA Technical Reports Server (NTRS)

    Chang, Manchium (Inventor); Colvin, Michael S. (Inventor)

    1989-01-01

    Magnetic polymer particles are formed by swelling porous, polymer particles and impregnating the particles with an aqueous solution of precursor magnetic metal salt such as an equimolar mixture of ferrous chloride and ferric chloride. On addition of a basic reagent such as dilute sodium hydroxide, the metal salts are converted to crystals of magnetite which are uniformly contained througout the pores of the polymer particle. The magnetite content can be increased and neutral buoyancy achieved by repetition of the impregnaton and neutralization steps to adjust the magnetite content to a desired level.

  14. Microfabricated optofluidic ring resonator structures

    PubMed Central

    Scholten, Kee; Fan, Xudong; Zellers, Edward. T.

    2011-01-01

    We describe the fabrication and preliminary optical characterization of rugged, Si-micromachined optofluidic ring resonator (μOFRR) structures consisting of thin-walled SiOx cylinders with expanded midsections designed to enhance the three-dimensional confinement of whispering gallery modes (WGMs). These μOFRR structures were grown thermally at wafer scale on the interior of Si molds defined by deep-reactive-ion etching and pre-treated to reduce surface roughness. Devices 85-μm tall with 2-μm thick walls and inner diameters ranging from 50 to 200 μm supported pure-mode WGMs with Q-factors >104 near 985 nm. Advantages for eventual vapor detection in gas chromatographic microsystems are highlighted. PMID:22053110

  15. FIB Microfabrication Software Design Considerations

    NASA Astrophysics Data System (ADS)

    Thompson, W.; Bowe, T.; Morlock, S.; Moskowitz, A.; Plourde, G.; Spaulding, G.; Scialdone, C.; Tsiang, E.

    1986-06-01

    Profit margins on high-volume ICs, such as the 256-K DRAM, are now inadequate. U.S. and foreign manufacturers cannot fully recover the ICs' engineering costs before a new round of product competition begins. Consequently, some semiconductor manufacturers are seeking less competitive designs with healthier, longer lasting profitability. These designs must be converted quickly from CAD to functional circuits in order for irofits to be realized. For ultrahigh performance devices, customized circuits, and rapid verification of design, FIB (focused ion beam) systems provide a viable alternative to the lengthy process of producing a large mask set. Early models of FI equipment did not require sophisticated software. However, as FIB technology approaches adolescence, it must be supported by software that gives the user a friendly system, the flexibility to design a wide variety of circuits, and good growth potential for tomorrow's ICs. Presented here is an overview of IBT's MicroFocus" 150 hardware, followed by descriptions of several MicroFocus software modules. Data preparation techniques from IBCAD formats to chip layout are compared to the more conventional lithographies. The MicroFocus 150 schemes for user interfacing, error logging, calibration, and subsystem control are given. The MicroFocus's pattern generator and bit slice software are explained. IBT's FIB patterning algorithms, which allow the fabrication of unique device types, are reviewed.

  16. Microfabricated silicon biosensors for microphysiometry

    NASA Technical Reports Server (NTRS)

    Bousse, L. J.; Libby, J. M.; Parce, J. W.

    1993-01-01

    Microphysiometers are biosensor devices that measure the metabolic rate of living cells by detecting the rate of extracellular acidification caused by a small number of cells. The cells are entrapped in a microvolume chamber, whose bottom surface is a silicon sensor chip. In a further miniaturization step, we have recently fabricated multichannel flow-through chips that will allow greater throughput and multiplicity. Microphysiometer technology can be applied to the detection of microorganisms. We describe the sensitive detection of bacteria and yeast. Further applications of microphysiometry to the characterization of microorganisms can be anticipated.

  17. Microfabricated Ice-Detection Sensor

    NASA Technical Reports Server (NTRS)

    DeAnna, Russell G.; Mehregany, Mehran; Roy, Shuvo; Zakar, Eugene

    1997-01-01

    Knowledge of ice conditions on important aircraft lift and control surfaces is critical for safe operation. These conditions can be determined with conventional ice-detection sensors, but these sensors are often expensive, require elaborate installation procedures, and interrupt the airflow. A micromachined, silicon-based, flush-mounted sensor which generates no internal heat has been designed, batch fabricated, packaged, and tested. The sensor is capable of distinguishing between an ice-covered and a clean surface. It employs a bulk micromachined wafer with a 7 micrometer-thick, boron-doped, silicon diaphragm which serves as one plate of a parallel-plate capacitor. This is bonded to a second silicon wafer which contains the fixed electrodes, one to drive the diaphragm by application of a voltage, the other to measure the deflection by a change in capacitance. The diaphragm sizes ranged from 1x1 mm to 3x3 mm, and the gap between parallel-plate capacitors is 2 micrometers. A 200 V d.c. was applied to the driving electrode which caused the capacitance to increase approximately 0.6pf, from a nominal capacitance of 0.6pf, when the surface was ice free. After the sensor was cooled below the freezing point of water, the same voltage range was applied to the drive electrode. The capacitance increased by the same amount. Then a drop of water was placed over the diaphragm and allowed to freeze. This created an approximately 2mm-thick ice layer. The applied 200V d.c. produced no change in capacitance, confirming that the diaphragm was locked to the ice layer. Since the sensor uses capacitive actuation, it uses very little power and is an ideal candidate for inclusion in a wireless sensing system.

  18. Microfabricated packed gas chromatographic column

    DOEpatents

    Kottenstette, Richard; Matzke, Carolyn M.; Frye-Mason, Gregory C.

    2003-12-16

    A new class of miniaturized gas chromatographic columns has been invented. These chromatographic columns are formed using conventional micromachining techniques, and allow packed columns having lengths on the order of a meter to be fabricated with a footprint on the order of a square centimeter.

  19. Magnetic tape

    NASA Technical Reports Server (NTRS)

    Robinson, Harriss

    1992-01-01

    The move to visualization and image processing in data systems is increasing the demand for larger and faster mass storage systems. The technology of choice is magnetic tape. This paper briefly reviews the technology past, present, and projected. A case is made for standards and the value of the standards to users.

  20. "Swinging" Magnets

    ERIC Educational Resources Information Center

    Languis, Marlin

    1975-01-01

    Presents detailed teaching plans for activities with "rubberized" magnets as well as background information and alternative teaching-learning approaches. This activity may be used to develop student skills in inferring and in observing evidence of interaction. Includes instructions for equipment construction. (BR)

  1. Magnetic Liquids

    NASA Technical Reports Server (NTRS)

    1987-01-01

    Ferrofluidics Corporation's recent innovation is a spindle for rotating computer discs that supports the disc's rotating shaft on a film of magnetic fluid instead of conventional ball bearings. According to its developers, the spindle offers greatly increased rotational stability, meaning substantially reduced vibration and mechanical noise, and non- repeatable runout. This allows disc drives to store two to 10 times more information.

  2. Superconducting Magnets for Magnetic Resonance Imaging

    NASA Astrophysics Data System (ADS)

    Feenan, Peter

    2000-03-01

    MRI is now a well established diagnostic technique in medicine. The richness of information provided by magnetic resonance gives rise to a variety of techniques which in turn leads to a variety of magnet designs. Magnet designers must consider suitable superconduting materials for the magnet, but need also to consider the overall fomat of the magnet to maximise patient comfort, access for clinicians and convenience of use - in some examples magnets are destined for use within the operating theatre and special considerations are required for this. Magnet types include; (1) low-field general purpose imagers, (2) extremity imaging, (3) open magnets with exellent all-round access often employing iron or permanent magnetic materials, (4) high-field magnets, and (5) very high-field (7 Tesla and more) magnets for spectroscopy and functional imaging research. Examples of these magnet varieties will be shown and some of the design challenges discussed.

  3. Permanent magnet array for the magnetic refrigerator

    NASA Astrophysics Data System (ADS)

    Lee, S. J.; Kenkel, J. M.; Pecharsky, V. K.; Jiles, D. C.

    2002-05-01

    Recent research into the development of magnetic refrigeration (MR) operating at room temperature has shown that it can provide a reliable, energy-efficient cooling system. To enhance the cooling power of the magnetic refrigerator, it is required to use a magnetic refrigerant material with large magnetocaloric effect (MCE) at the appropriate temperature. Most advanced magnetic refrigerant materials show largest MCE at high applied magnetic fields generated by a superconducting magnet. For application of MCE to air conditioners or household refrigerators, it is essential to develop a permanent magnet array to form a compact, strong, and energy-efficient magnetic field generator. Generating a magnetic field well above the remanence of a permanent magnet material is hard to achieve through conventional designs. A permanent magnet array based on a hollow cylindrical flux source is found to provide an appropriate geometry and magnetic field strength for MR applications.

  4. Magnetic bearing. [for supplying magnetic fluxes

    NASA Technical Reports Server (NTRS)

    Studer, P. A. (Inventor)

    1975-01-01

    A magnetic bearing is described which includes a pair of coaxial, toroidal, and permanent magnets having axially directed poles. Like poles of the permanent magnets are adjacent to each other, whereby the permanent magnets have a tendency to be urged apart along the common axis. An electromagnet is wound coaxially with the permanent magnets in such a manner that the poles are axially directed. Between the poles of each permanent magnet there is a low magnetic reluctance circuit including two series air gaps. Between the poles of the electromagnet a low reluctance path including only one air gap of each of the low magnetic reluctance circuits is provided. The low reluctance path for the electromagnet includes a ring axially translatable relative to the permanent magnets. The ring forms opposite faces of the air gaps in the magnetic circuits for each permanent magnet.

  5. Magnetic Storms

    NASA Technical Reports Server (NTRS)

    Tsurutani, B. T.; Gonzalez, W. D.; Kamide, Y.

    1996-01-01

    This talk provides a brief summary of the first conference devoted entirely to magnetic storms. Topics cover the relevant phenomena at the Sun/corona, propogation of these structures through interplanetary space, the response of the magnetosphere to interaction with these interplanetary structures, the formation of the storm time ring current (in particular the oxygen content of the ring-current), and storm ionospheric effects and ground based effects.

  6. Magnetic cumulation

    NASA Astrophysics Data System (ADS)

    Pavlovskij, A. I.

    1990-08-01

    The second half of 40-th -finish of 60-th of the XX-th Century were prolific y ears of scientific activity of A.D. Sakharov (1921-1990), when his unique creati ve aptitudes and inventivity has found a wide manifestation. Besides of his decis ive contribution to creation of Soviet thermonuclear weapons, in the area of his interests entered various problems of tehrmonuclaer energetics. In 1950 I.E. Tam m and A.D. Sakharov formulated the principles of magnetic thermoisolation of High temperature Plasmas, which put a beginning to controlled thermonuclear synthesis in the U.S.S.R. In 1951 A.D. Sakharov developed the theory of magnetic stationa ry thermonuclear reactor, which are closed to modern Tokamaks. Approximately in 1960-1961 He examined the possibility of thermonuclear synthesis on the basis of L aser compression of a spherical target. The idea of magnetic cumulation was forwrded by A.D. Sakharov as one of the ways of the obtaining of a controlled impulse thermonuclear reaction.

  7. Magnetic Reconnection

    SciTech Connect

    Masaaki Yamada, Russell Kulsrud and Hantao Ji

    2009-09-17

    We review the fundamental physics of magnetic reconnection in laboratory and space plasmas, by discussing results from theory, numerical simulations, observations from space satellites, and the recent results from laboratory plasma experiments. After a brief review of the well-known early work, we discuss representative recent experimental and theoretical work and attempt to interpret the essence of significant modern findings. In the area of local reconnection physics, many significant findings have been made with regard to two- uid physics and are related to the cause of fast reconnection. Profiles of the neutral sheet, Hall currents, and the effects of guide field, collisions, and micro-turbulence are discussed to understand the fundamental processes in a local reconnection layer both in space and laboratory plasmas. While the understanding of the global reconnection dynamics is less developed, notable findings have been made on this issue through detailed documentation of magnetic self-organization phenomena in fusion plasmas. Application of magnetic reconnection physics to astrophysical plasmas is also brie y discussed.

  8. Loess magnetism

    NASA Astrophysics Data System (ADS)

    Heller, Friedrich; Evans, Michael E.

    Loess is a wind-blown Quaternary silt deposit that blankets vast tracts of land and in places reaches thicknesses in excess of 300 m. Over the last decade it has emerged that certain loess sections have recorded the polarity history of the geomagnetic field and now provide essentially continuous magnetostratigraphic archives covering the last 2-3 m.y. Indeed, it is the chronology provided by the magnetic polarity signature itself that was largely responsible for establishing the timing of the initiation of loess accumulation, particularly in the celebrated Chinese loess plateau, where a starting date close to the Gauss-Matuyama chron boundary (2.6 Ma) is now firmly established. This coincides with a widely documented global climatic shift and accelerated uplift of the Tibetan planteau. Many loess sections contain fossil soils (paleosols) that bear witness to warmer and wetter climatic conditions corresponding to interglacial periods in contrast to the cold, arid environments in which pristine loess accumulated and which correspond to glacial intervals. The resulting sequences of alternating loess and paleosols also manifest themselves magnetically, in this case in terms of susceptibility changes, entirely distinct from the remanence characteristics, which encode the geomagnetic polarity. The susceptibility time series obtained from localities in Alaska and China correlate remarkably well with the oceanic oxygen isotope signal and yield spectral power estimates in agreement with those predicted by the astronomical (Milankovitch) theory of ice ages. Comparisons of susceptibility patterns with corresponding profiles of 10Be concentration in loess allows major changes in rainfall to be estimated. In China, for example data spanning the last 130 kyr (corresponding to oxygen isotope stages 1-5) indicate that paleoprecipitation was almost halved (from ≃540 to ≃310 mm yr-1) as the warm interglacial during which paleosol S1 formed gave way to the following glacial

  9. Ferroelectricity in spiral magnets.

    PubMed

    Mostovoy, Maxim

    2006-02-17

    It was recently observed that the ferroelectrics showing the strongest sensitivity to an applied magnetic field are spiral magnets. We present a phenomenological theory of inhomogeneous ferroelectric magnets, which describes their thermodynamics and magnetic field behavior, e.g., dielectric susceptibility anomalies at magnetic transitions and sudden flops of electric polarization in an applied magnetic field. We show that electric polarization can also be induced at domain walls and that magnetic vortices carry electric charge. PMID:16606047

  10. Magnetic Storms

    NASA Technical Reports Server (NTRS)

    Tsurutani, Bruce T.; Gonzalez, Walter D.

    1998-01-01

    One of the oldest mysteries in geomagnetism is the linkage between solar and geomagnetic activity. The 11-year cycles of both the numbers of sunspots and Earth geomagnetic storms were first noted by Sabine. A few years later, speculation on a causal relationship between flares and storms arose when Carrington reported that a large magnetic storm followed the great September 1859 solar flare. However, it was not until this century that a well-accepted statistical survey on large solar flares and geomagnetic storms was performed, and a significant correlation between flares and geomagnetic storms was noted. Although the two phenomena, one on the Sun and the other on the Earth, were statistically correlated, the exact physical linkage was still an unknown at this time. Various hypotheses were proposed, but it was not until interplanetary spacecraft measurements were available that a high-speed plasma stream rich in helium was associated with an intense solar flare. The velocity of the solar wind increased just prior to and during the helium passage, identifying the solar ejecta for the first time. Space plasma measurements and Skylab's coronagraph images of coronal mass elections (CMES) from the Sun firmly established the plasma link between the Sun and the Earth. One phenomenon associated with magnetic storms is brilliant "blood" red auroras, as shown.

  11. Superconducting magnet

    DOEpatents

    Satti, John A.

    1980-01-01

    A superconducting magnet designed to produce magnetic flux densities of the order of 4 to 5 Webers per square meter is constructed by first forming a cable of a plurality of matrixed superconductor wires with each wire of the plurality insulated from each other one. The cable is shaped into a rectangular cross-section and is wound with tape in an open spiral to create cooling channels. Coils are wound in a calculated pattern in saddle shapes to produce desired fields, such as dipoles, quadrupoles, and the like. Wedges are inserted between adjacent cables as needed to maintain substantially radial placement of the long dimensions of cross sections of the cables. After winding, individual strands in each of the cables are brought out to terminals and are interconnected to place all of the strands in series and to maximize the propagation of a quench by alternating conduction from an inner layer to an outer layer and from top half to bottom half as often as possible. Individual layers are separated from others by spiraled aluminum spacers to facilitate cooling. The wound coil is wrapped with an epoxy tape that is cured by heat and then machined to an interference fit with an outer aluminum pipe which is then affixed securely to the assembled coil by heating it to make a shrink fit. In an alternate embodiment, one wire of the cable is made of copper or the like to be heated externally to propagate a quench.

  12. Magnetic Nanoparticle Sensors

    PubMed Central

    Koh, Isaac; Josephson, Lee

    2009-01-01

    Many types of biosensors employ magnetic nanoparticles (diameter = 5–300 nm) or magnetic particles (diameter = 300–5,000 nm) which have been surface functionalized to recognize specific molecular targets. Here we cover three types of biosensors that employ different biosensing principles, magnetic materials, and instrumentation. The first type consists of magnetic relaxation switch assay-sensors, which are based on the effects magnetic particles exert on water proton relaxation rates. The second type consists of magnetic particle relaxation sensors, which determine the relaxation of the magnetic moment within the magnetic particle. The third type is magnetoresistive sensors, which detect the presence of magnetic particles on the surface of electronic devices that are sensitive to changes in magnetic fields on their surface. Recent improvements in the design of magnetic nanoparticles (and magnetic particles), together with improvements in instrumentation, suggest that magnetic material-based biosensors may become widely used in the future. PMID:22408498

  13. Thin Magnetically Soft Wires for Magnetic Microsensors

    PubMed Central

    Zhukova, Valentina; Ipatov, Mihail; Zhukov, Arcady

    2009-01-01

    Recent advances in technology involving magnetic materials require development of novel advanced magnetic materials with improved magnetic and magneto-transport properties and with reduced dimensionality. Therefore magnetic materials with outstanding magnetic characteristics and reduced dimensionality have recently gained much attention. Among these magnetic materials a family of thin wires with reduced geometrical dimensions (of order of 1–30 μm in diameter) have gained importance within the last few years. These thin wires combine excellent soft magnetic properties (with coercivities up to 4 A/m) with attractive magneto-transport properties (Giant Magneto-impedance effect, GMI, Giant Magneto-resistance effect, GMR) and an unusual re-magnetization process in positive magnetostriction compositions exhibiting quite fast domain wall propagation. In this paper we overview the magnetic and magneto-transport properties of these microwires that make them suitable for microsensor applications. PMID:22291562

  14. Magnet innovations for linacs

    SciTech Connect

    Halbach, K.

    1986-06-01

    It is possible to produce large magnetic fields at the aperture of permanent magnet quadrupoles, even when the magnetic aperture is very small. That, combined with their compactness, makes permanent magnet quadrupoles very powerful components of small aperture linacs. Results will be presented about past and present work on both fixed and variable strength permanent magnets suitable for use in and around linacs.

  15. The magnetization process: Hysteresis

    NASA Technical Reports Server (NTRS)

    Balsamel, Richard

    1990-01-01

    The magnetization process, hysteresis (the difference in the path of magnetization for an increasing and decreasing magnetic field), hysteresis loops, and hard magnetic materials are discussed. The fabrication of classroom projects for demonstrating hysteresis and the hysteresis of common magnetic materials is described in detail.

  16. Magnetic field sensor

    NASA Astrophysics Data System (ADS)

    Silva, Nicolas

    2012-09-01

    Earlier papers1-3 in this journal have described experiments on measuring the magnetic fields of current-carrying wires and permanent magnets using magnetic field probes of various kinds. This paper explains how to use an iPad and the free app MagnetMeter-3D Vector Magnetometer and Accelerometer4 (compass HD) to measure the magnetic fields.

  17. Permanent magnet assembly

    DOEpatents

    Chell, Jeremy; Zimm, Carl B.

    2006-12-12

    A permanent magnet assembly is disclosed that is adapted to provide a magnetic field across an arc-shaped gap. Such a permanent magnet assembly can be used, for example, to provide a time-varying magnetic field to an annular region for use in a magnetic refrigerator.

  18. Two-Dimensional Aperture Coding for Magnetic Sector Mass Spectrometry

    NASA Astrophysics Data System (ADS)

    Russell, Zachary E.; Chen, Evan X.; Amsden, Jason J.; Wolter, Scott D.; Danell, Ryan M.; Parker, Charles B.; Stoner, Brian R.; Gehm, Michael E.; Brady, David J.; Glass, Jeffrey T.

    2015-02-01

    In mass spectrometer design, there has been a historic belief that there exists a fundamental trade-off between instrument size, throughput, and resolution. When miniaturizing a traditional system, performance loss in either resolution or throughput would be expected. However, in optical spectroscopy, both one-dimensional (1D) and two-dimensional (2D) aperture coding have been used for many years to break a similar trade-off. To provide a viable path to miniaturization for harsh environment field applications, we are investigating similar concepts in sector mass spectrometry. Recently, we demonstrated the viability of 1D aperture coding and here we provide a first investigation of 2D coding. In coded optical spectroscopy, 2D coding is preferred because of increased measurement diversity for improved conditioning and robustness of the result. To investigate its viability in mass spectrometry, analytes of argon, acetone, and ethanol were detected using a custom 90-degree magnetic sector mass spectrometer incorporating 2D coded apertures. We developed a mathematical forward model and reconstruction algorithm to successfully reconstruct the mass spectra from the 2D spatially coded ion positions. This 2D coding enabled a 3.5× throughput increase with minimal decrease in resolution. Several challenges were overcome in the mass spectrometer design to enable this coding, including the need for large uniform ion flux, a wide gap magnetic sector that maintains field uniformity, and a high resolution 2D detection system for ion imaging. Furthermore, micro-fabricated 2D coded apertures incorporating support structures were developed to provide a viable design that allowed ion transmission through the open elements of the code.

  19. Two-dimensional aperture coding for magnetic sector mass spectrometry.

    PubMed

    Russell, Zachary E; Chen, Evan X; Amsden, Jason J; Wolter, Scott D; Danell, Ryan M; Parker, Charles B; Stoner, Brian R; Gehm, Michael E; Brady, David J; Glass, Jeffrey T

    2015-02-01

    In mass spectrometer design, there has been a historic belief that there exists a fundamental trade-off between instrument size, throughput, and resolution. When miniaturizing a traditional system, performance loss in either resolution or throughput would be expected. However, in optical spectroscopy, both one-dimensional (1D) and two-dimensional (2D) aperture coding have been used for many years to break a similar trade-off. To provide a viable path to miniaturization for harsh environment field applications, we are investigating similar concepts in sector mass spectrometry. Recently, we demonstrated the viability of 1D aperture coding and here we provide a first investigation of 2D coding. In coded optical spectroscopy, 2D coding is preferred because of increased measurement diversity for improved conditioning and robustness of the result. To investigate its viability in mass spectrometry, analytes of argon, acetone, and ethanol were detected using a custom 90-degree magnetic sector mass spectrometer incorporating 2D coded apertures. We developed a mathematical forward model and reconstruction algorithm to successfully reconstruct the mass spectra from the 2D spatially coded ion positions. This 2D coding enabled a 3.5× throughput increase with minimal decrease in resolution. Several challenges were overcome in the mass spectrometer design to enable this coding, including the need for large uniform ion flux, a wide gap magnetic sector that maintains field uniformity, and a high resolution 2D detection system for ion imaging. Furthermore, micro-fabricated 2D coded apertures incorporating support structures were developed to provide a viable design that allowed ion transmission through the open elements of the code. PMID:25510933

  20. Dual magnetoresistive heads for high-density magnetic recording

    NASA Astrophysics Data System (ADS)

    Trindade, Isabel Maria Goncalves

    2000-11-01

    In this thesis, novel magnetoresistive heads were developed and tested. The head designs had been proposed and analyzed with 3-D micromagnetic simulations. The dual magnetoresistive heads were of technological interest because they could provide higher linear resolution than conventional magnetoresistive heads, with less micro- fabrication complexity. As the demands for higher storage capacity and higher data rate increase, it is important to investigate alternative transducer designs that can provide suitable signal to noise ratio at smaller bits (smaller track-widths, narrower separation between tracks and smaller bit lengths). Dual magnetoresistive heads with track-widths of 2 microns and gap lengths of 80 nm were fabricated by micro-fabrication techniques. Thin film materials incorporating magnetic materials, metals and insulators were developed and prepared by sputtering. Optical lithography processes were developed and used to pattern the films with lateral dimensions of the order of a micron. Read-elements on wafers were characterized by Kerr microscope imaging and magnetoresistance measurements. The characterization involved single domain state stabilization, antiparallel magnetic state and electrical and magnetic mismatch between the two permalloy stripes of the dual magnetoresistive read- elements. The read-elements were built into nano-sliders and tested on spin stands with either two arm actuators (one for the read head, another for the write head) or a commercial Gukiz spin stand provided with one actuator for two separate heads. The time-domain response, spectral response, cross track-profile, off-track response and adjacent track interference were tested and the experimental results compared to theoretical models. The head performance on longitudinal medium with an areal magnetic product of Mrδ = 0-5 memu/cm2 and Mr δ = 1 memu/cm2 indicate that the head operated mainly in a linear regime, with a signal output amplitude directly proportional to the