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Sample records for laser machined microwell

  1. Development and operation of laser machined MicroWell Detectors

    CERN Document Server

    Pitts, W K; Belolipetskiy, S V; Crain, M; Hutchins, J B; Matos, S; Walsh, K M; Solberg, K

    1999-01-01

    Arrays of 100 mu m diameter cylindrical wells were laser micromachined on a 200 micrometer Cartesian grid, producing MicroWell Detectors (MWD). The substrate was 125 mu m thick polyimide foil, more than twice as thick as a typical GEM or WELL detector. An advantage of the laser micromachining process is that the wells are produced with nearly vertical sidewalls, in contrast to the sloping sidewalls characteristic of conventional chemical etching processes. With the steeper sidewall, active elements may be more closely packed than is possible with wet etching techniques. Thicker substrates can be patterned, increasing the length of the charge multiplication region and reducing the internal capacitance per unit element. A series of prototypes have been produced and tested in a counting gas composed of 85% argon and 15% carbon dioxide, with a maximum measured gas gain of approximately 12 000.

  2. Imaging micro-well proportional counters fabricated with masked UV laser ablation

    CERN Document Server

    Deines-Jones, P; Crawford, H; Hunter, S D

    2002-01-01

    The micro-well detector is a gas-proportional counter similar to the CAT (Bartol et al., J. Phys. III 6 (1996) 337) and WELL detectors (Bellazzini et al., Nucl. Instr. and Meth. A 423 (1999) 125). The micro-well is a cylindrical hole formed in the polymer substrate of commercially fabricated copper-clad flexible printed circuit board by UV laser ablation. The micro-wells are drilled at GSFC's UV laser-ablation facility. The cathode is a metal annulus that surrounds the opening of the well. The anode is a metal pad that fills the bottom of the well. Advantages of this topology include intrinsic two-dimensional sensing, thick robust electrodes, and large localized image charge on the cathodes. We have fabricated 5 cmx5 cm micro-well detectors with segmented anodes (1-d) and with both anodes and cathodes segmented (2-d), and have demonstrated: - stable, proportional operation at gas gains in excess of 30,000 in Ar- and Xe-based gases; - FWHM energy resolution of 20% at 6 keV in P-10; - preliminary 1-d spatial re...

  3. Laser-based directed release of array elements for efficient collection into targeted microwells.

    Science.gov (United States)

    Dobes, Nicholas C; Dhopeshwarkar, Rahul; Henley, W Hampton; Ramsey, J Michael; Sims, Christopher E; Allbritton, Nancy L

    2013-02-21

    A cell separation strategy capable of the systematic isolation and collection of moderate to large numbers (25-400) of single cells into a targeted microwell is demonstrated. An array of microfabricated, releasable, transparent micron-scale pedestals termed pallets and an array of microwells in poly(dimethylsiloxane) (PDMS) were mated to enable selective release and retrieval of individual cells. Cells cultured on a pallet array mounted on a custom designed stage permitted the array to be positioned independently of the microwell locations. Individual pallets containing cells were detached in a targeted fashion using a pulsed Nd:YAG laser. The location of the laser focal point was optimized to transfer individual pallets to designated microwells. In a large-scale sort (n = 401), the accuracy, defined as placing a pallet in the intended well, was 94% and the collection efficiency was 100%. Multiple pallets were observed in only 4% of the targeted wells. In cell sorting experiments, the technique provided a yield and purity of target cells identified by their fluorescence signature of 91% and 93%, respectively. Cell viability based on single-cell cloning efficiency at 72 h post collection was 77%.

  4. Laser machining of advanced materials

    CERN Document Server

    Dahotre, Narendra B

    2011-01-01

    Advanced materialsIntroductionApplicationsStructural ceramicsBiomaterials CompositesIntermetallicsMachining of advanced materials IntroductionFabrication techniquesMechanical machiningChemical Machining (CM)Electrical machiningRadiation machining Hybrid machiningLaser machiningIntroductionAbsorption of laser energy and multiple reflectionsThermal effectsLaser machining of structural ceramicsIntrodu

  5. Laser machining of explosives

    Science.gov (United States)

    Perry, Michael D.; Stuart, Brent C.; Banks, Paul S.; Myers, Booth R.; Sefcik, Joseph A.

    2000-01-01

    The invention consists of a method for machining (cutting, drilling, sculpting) of explosives (e.g., TNT, TATB, PETN, RDX, etc.). By using pulses of a duration in the range of 5 femtoseconds to 50 picoseconds, extremely precise and rapid machining can be achieved with essentially no heat or shock affected zone. In this method, material is removed by a nonthermal mechanism. A combination of multiphoton and collisional ionization creates a critical density plasma in a time scale much shorter than electron kinetic energy is transferred to the lattice. The resulting plasma is far from thermal equilibrium. The material is in essence converted from its initial solid-state directly into a fully ionized plasma on a time scale too short for thermal equilibrium to be established with the lattice. As a result, there is negligible heat conduction beyond the region removed resulting in negligible thermal stress or shock to the material beyond a few microns from the laser machined surface. Hydrodynamic expansion of the plasma eliminates the need for any ancillary techniques to remove material and produces extremely high quality machined surfaces. There is no detonation or deflagration of the explosive in the process and the material which is removed is rendered inert.

  6. Microwell arrays with nanoholes

    Science.gov (United States)

    Folch, Albert (Inventor); Kosar, Turgut Fettah (Inventor)

    2009-01-01

    A device for conducting parallel analysis or manipulation of multiple cells or biomolecules is disclosed. In one embodiment, the device comprises a silicon chip with a microwell, and at least one membrane suspended at the bottom opening of the microwell. The suspended portion of the membrane defines a nanohole that provides access to the material on the other side of the membrane.

  7. Laser applications in machining slab materials

    Science.gov (United States)

    Zhang, Xiaoping

    1990-10-01

    Since the invention of the laser back in 1960, laser technology has been extensively applied in many fields of science and technology. These has been a history of nearly two decades of using lasers as an energy source in machining materials, such as cutting, welding, ruling and boring, among other operations. With the development of flexible automation in production, the advantages of laser machining have has grown more and more obvious. The combination of laser technology and computer science further promotes the enhancement and upgrading of laser machining and related equipment. At present, many countries are building high quality laser equipment for machining slab materials, such as the Coherent and Spectra Physics corporations in the United States, the Trumpf Corporation in West Germany, the Amada Corporation in Japan, and the Bystronic Corporation in Switzerland, among other companies.

  8. Millisecond laser machining of transparent materials assisted by nanosecond laser.

    Science.gov (United States)

    Pan, Yunxiang; Zhang, Hongchao; Chen, Jun; Han, Bing; Shen, Zhonghua; Lu, Jian; Ni, Xiaowu

    2015-01-26

    A new form of double pulse composed of a nanosecond laser and a millisecond laser is proposed for laser machining transparent materials. To evaluate its advantages and disadvantages, experimental investigations are carried out and the corresponding results are compared with those of single millisecond laser. The mechanism is discussed from two aspects: material defects and effects of modifications induced by nanosecond laser on thermal stress field during millisecond laser irradiation. It is shown that the modifications of the sample generated by nanosecond laser improves the processing efficiency of subsequent millisecond laser, while limits the eventual size of modified region.

  9. LASER CUTTING MACHINES FOR 3-D THIN SHEET PARTS

    Directory of Open Access Journals (Sweden)

    Miroslav RADOVANOVIC

    2012-11-01

    Full Text Available Laser cutting machines are used for precise contour cutting thin sheet. In industrial application nowadays various types and construction of laser cutting machines can be met. For contour cutting 3-D thin sheet parts laser cutting machines with rotation movements and laser robots are used. Laser generates the light beam, that presents a tool in working process. Application of laser cutting machines made possible good quality of products, flexibility of production and enlargement of economy

  10. Laser-assisted machining of difficult-to-machine materials

    Energy Technology Data Exchange (ETDEWEB)

    Incropera, F.P.; Rozzi, J.C.; Pfefferkorn, F.E.; Lei, S.; Shin, Y.C.

    1999-07-01

    Laser-assisted machining (LAM) is a hybrid process for which a difficult-to-machine material, such as a ceramic or super alloy, is irradiated by a laser source prior to material removal by a cutting tool. The process has the potential to significantly increase material removal rates, as well as to improve the geometry and properties of the finished work piece. Features and limitations of theoretical and experimental procedures for determining the transient thermal response of a work piece during LAM are described, and representative results are presented for laser-assisted turning of sintered silicon nitride. Significant physical trends are revealed by the calculations, as are guidelines for the selection of appropriate operating conditions.

  11. Laser Machining of Melt Infiltrated Ceramic Matrix Composite

    Science.gov (United States)

    Jarmon, D. C.; Ojard, G.; Brewer, D.

    2012-01-01

    As interest grows in considering the use of ceramic matrix composites for critical components, the effects of different machining techniques, and the resulting machined surfaces, on strength need to be understood. This work presents the characterization of a Melt Infiltrated SiC/SiC composite material system machined by different methods. While a range of machining approaches were initially considered, only diamond grinding and laser machining were investigated on a series of tensile coupons. The coupons were tested for residual tensile strength, after a stressed steam exposure cycle. The data clearly differentiated the laser machined coupons as having better capability for the samples tested. These results, along with micro-structural characterization, will be presented.

  12. Pulsed laser-assisted machining of Inconel 718 superalloy

    Science.gov (United States)

    Azhdari Tadavani, Soheila; Shoja Razavi, Reza; Vafaei, Reza

    2017-01-01

    Nickel-based superalloys including Inconel 718(IN718) are widely used in aerospace industries due to their superior high temperature strength, toughness, and corrosion resistance. These alloys are difficult to machine mainly because of their low thermal conductivity and high work hardening rate, which cause steep temperature gradient and high cutting forces at the tool edge. The application of laser assisted machining is the subject of many new researches since shear forces; surface coarsening and tool wear are reduced. The aim of this investigation was to evaluate laser assisted machining behavior of a 718 Inconel superalloy from the view point of machining specific energy, surface roughness, tool wear and chip appearance. Experimental apparatuses used included optical and scanning electron microscopy, spark emission spectroscopy, and EDS analysis. The results indicated that increasing the temperature to about 540 °C just ahead of primary shear zone, can result in 35% reduction of machining specific energy, in comparison with conventional machining. Furthermore, surface coarsening and tool wear were reduced by 22% and 23% respectively. Flank wear was the main deteriorating factor on cutting tools during laser assisted machining. SEM micrographs indicated that increase in temperature has no noticeable effect on finished workpiece surface. Analysis of variance obtained from regression analysis indicated that frequency of laser beam has the most influential effect on temperature. The optimum conditions for laser assisted machining of 718 superalloy is suggested as follows: 80 Hz frequency, 400 W power, 24 m/min cutting speed, and 0.052 mm/rev feed rate along with 540 °C temperature, 2.51 J/mm2 machining specific energy and 130 N cutting force.

  13. TEA CO2 laser machining of CFRP composite

    Science.gov (United States)

    Salama, A.; Li, L.; Mativenga, P.; Whitehead, D.

    2016-05-01

    Carbon fibre-reinforced polymer (CFRP) composites have found wide applications in the aerospace, marine, sports and automotive industries owing to their lightweight and acceptable mechanical properties compared to the commonly used metallic materials. Machining of CFRP composites using lasers can be challenging due to inhomogeneity in the material properties and structures, which can lead to thermal damages during laser processing. In the previous studies, Nd:YAG, diode-pumped solid-state, CO2 (continuous wave), disc and fibre lasers were used in cutting CFRP composites and the control of damages such as the size of heat-affected zones (HAZs) remains a challenge. In this paper, a short-pulsed (8 μs) transversely excited atmospheric pressure CO2 laser was used, for the first time, to machine CFRP composites. The laser has high peak powers (up to 250 kW) and excellent absorption by both the carbon fibre and the epoxy binder. Design of experiment and statistical modelling, based on response surface methodology, was used to understand the interactions between the process parameters such as laser fluence, repetition rate and cutting speed and their effects on the cut quality characteristics including size of HAZ, machining depth and material removal rate (MRR). Based on this study, process parameter optimization was carried out to minimize the HAZ and maximize the MRR. A discussion is given on the potential applications and comparisons to other lasers in machining CFRP.

  14. Microfluidic microwell and microcapillary biochips

    Science.gov (United States)

    Minot, Michael J.; Stowe, David W.; Detarando, Michael A.; Krans, Joseph A.; Kass, Jason L.

    2006-02-01

    Utilizing nanotechnology, proprietary chemistry, and microfluidics, innovative firms are developing biochips and instrument systems that enable high-speed automated biomedical sequencing. Incom Inc. presents development results on five novel biochip technologies based on FiberOptic MicroSlide and microcapillary technology. FiberOptic MicroSlides are fiber optic interrogated (FOI) biochips made up of millions of fused optical fibers, and are uniquely suited as a platform for microarray applications. FiberOptic MicroSlides (henceforth referred to as "MicroSlides" or "slides" in this paper) act as a 'zero thickness substrate' transmitting optical signals from top to bottom without spreading, so that fluorescent or luminescent activity on the surface or within a well can be directly coupled to a CCD device without additional optics. In contrast to bulk optics, the slides are compact and have excellent light-gathering power. They are an alternative to conventional microscope slides for applications involving moderate-resolution bottom viewing (inverted microscopy). The surface of the MicroSlides can be etched or patterned with a permanent polymer to form microwell arrays, or microfluidic structures suitable for genomic and proteomic analysis, cell migration studies and other applications. Low-cost microcapillary array plates have also been developed. These plates act as microscopic test tubes, which enable picoliter reactions to be detected, counted and analyzed. Progress in developing large area (300 mm X 300 mm) arrays with up to 100 million capillaries, and diameter / length aspect ratios up to 10,000: 1 is presented. Results demonstrate negligible optical cross talk between capillaries, resulting in improved signal-to-noise ratios while minimizing false hits.

  15. Sub-micron-structure machining on silicon by femtosecond laser

    Institute of Scientific and Technical Information of China (English)

    Hung-Yin TSAI; Shao-Wei LUO; Chih-Wei WU; Shing-Hoa WANG

    2009-01-01

    Sub-micron-structure machining on silicon substrate was studied by direct writing system of femtosecond laser with the central wavelength of 800 nm, pulse duration of 120 fs and repetition rate of 1 kHz. Three kinds of experiments were conducted: 1) the effect of photoresist on silicon; 2) machinability of different orientations of silicon; and 3) the size of micro-structure and the cross-section shape. Photoresist SU8 was coated onto silicon substrates in thicknesses of 100 μm. SU8 remained on the silicon substrate while the silicon under the machined SU8 was removed after laser machining. Orientations of (100), (110), and (111) silicon substrates were machined with the laser power of 60 μW and the scanning speed of 3 ram/rain. Spike morphologies were observed on all three orientations of silicon substrates without obvious directional difference of these spikes on different silicon substrates. In addition, the ablation threshold energies were also similar. In the consideration of ablation energy, one numerical model of the machining parameters has been proposed to simulate the cross-section of the micro-structure. The predicted shape by simulation can fit the profile of the cross-section shape well.

  16. Volumetric verification of multiaxis machine tool using laser tracker.

    Science.gov (United States)

    Aguado, Sergio; Samper, David; Santolaria, Jorge; Aguilar, Juan José

    2014-01-01

    This paper aims to present a method of volumetric verification in machine tools with linear and rotary axes using a laser tracker. Beyond a method for a particular machine, it presents a methodology that can be used in any machine type. Along this paper, the schema and kinematic model of a machine with three axes of movement, two linear and one rotational axes, including the measurement system and the nominal rotation matrix of the rotational axis are presented. Using this, the machine tool volumetric error is obtained and nonlinear optimization techniques are employed to improve the accuracy of the machine tool. The verification provides a mathematical, not physical, compensation, in less time than other methods of verification by means of the indirect measurement of geometric errors of the machine from the linear and rotary axes. This paper presents an extensive study about the appropriateness and drawbacks of the regression function employed depending on the types of movement of the axes of any machine. In the same way, strengths and weaknesses of measurement methods and optimization techniques depending on the space available to place the measurement system are presented. These studies provide the most appropriate strategies to verify each machine tool taking into consideration its configuration and its available work space.

  17. Precision machining of pig intestine using ultrafast laser pulses

    Science.gov (United States)

    Beck, Rainer J.; Góra, Wojciech S.; Carter, Richard M.; Gunadi, Sonny; Jayne, David; Hand, Duncan P.; Shephard, Jonathan D.

    2015-07-01

    Endoluminal surgery for the treatment of early stage colorectal cancer is typically based on electrocautery tools which imply restrictions on precision and the risk of harm through collateral thermal damage to the healthy tissue. As a potential alternative to mitigate these drawbacks we present laser machining of pig intestine by means of picosecond laser pulses. The high intensities of an ultrafast laser enable nonlinear absorption processes and a predominantly nonthermal ablation regime. Laser ablation results of square cavities with comparable thickness to early stage colorectal cancers are presented for a wavelength of 1030 nm using an industrial picosecond laser. The corresponding histology sections exhibit only minimal collateral damage to the surrounding tissue. The depth of the ablation can be controlled precisely by means of the pulse energy. Overall, the application of ultrafast lasers to ablate pig intestine enables significantly improved precision and reduced thermal damage to the surrounding tissue compared to conventional techniques.

  18. Tunable shrink-induced honeycomb microwell arrays for uniform embryoid bodies.

    Science.gov (United States)

    Nguyen, Diep; Sa, Silin; Pegan, Jonathan D; Rich, Brent; Xiang, Guangxin; McCloskey, Kara E; Manilay, Jennifer O; Khine, Michelle

    2009-12-07

    Embryoid body (EB) formation closely recapitulates early embryonic development with respect to lineage commitment. Because it is greatly affected by cell-cell and cell-substrate interactions, the ability to control the initial number of cells in the aggregates and to provide an appropriate substrate are crucial parameters for uniform EB formation. Here we report of an ultra-rapid fabrication and culture method utilizing a laser-jet printer to generate closely arrayed honeycomb microwells of tunable sizes for the induction of uniform EBs from single cell suspension. By printing various microwell patterns onto pre-stressed polystyrene sheets, and through heat induced shrinking, high aspect micromolds are generated. Notably, we achieve rounded bottom polydimethylsiloxane (PDMS) wells not easily achievable with standard microfabrication methods, but critical to achieve spherical EBs. Furthermore, by simply controlling the size of the microwells and the concentration of the cell suspension we can control the initial size of the cell aggregate, thus influencing lineage commitment. In addition, these microwells are easily adaptable and scalable to most standard well plates and easily integrated into commercial liquid handling systems to provide an inexpensive and easy high throughput compound screening platform.

  19. Laser micro machining of medical devices.

    Science.gov (United States)

    Rausch, Y

    2009-01-01

    Excimer and increasingly ultra-short-pulsed lasers are important tools in the creation of microstructures and nanostructures. Capabilities of the latest systems are described, which include drilling 30-microm diameter holes in 50 to 100 microm thick metal foils and subsurface engraving of transparent materials.

  20. Thermal-mechanical modeling of laser ablation hybrid machining

    Science.gov (United States)

    Matin, Mohammad Kaiser

    2001-08-01

    Hard, brittle and wear-resistant materials like ceramics pose a problem when being machined using conventional machining processes. Machining ceramics even with a diamond cutting tool is very difficult and costly. Near net-shape processes, like laser evaporation, produce micro-cracks that require extra finishing. Thus it is anticipated that ceramic machining will have to continue to be explored with new-sprung techniques before ceramic materials become commonplace. This numerical investigation results from the numerical simulations of the thermal and mechanical modeling of simultaneous material removal from hard-to-machine materials using both laser ablation and conventional tool cutting utilizing the finite element method. The model is formulated using a two dimensional, planar, computational domain. The process simulation acronymed, LAHM (Laser Ablation Hybrid Machining), uses laser energy for two purposes. The first purpose is to remove the material by ablation. The second purpose is to heat the unremoved material that lies below the ablated material in order to ``soften'' it. The softened material is then simultaneously removed by conventional machining processes. The complete solution determines the temperature distribution and stress contours within the material and tracks the moving boundary that occurs due to material ablation. The temperature distribution is used to determine the distance below the phase change surface where sufficient ``softening'' has occurred, so that a cutting tool may be used to remove additional material. The model incorporated for tracking the ablative surface does not assume an isothermal melt phase (e.g. Stefan problem) for laser ablation. Both surface absorption and volume absorption of laser energy as function of depth have been considered in the models. LAHM, from the thermal and mechanical point of view is a complex machining process involving large deformations at high strain rates, thermal effects of the laser, removal of

  1. Field precision machining technology of target chamber in ICF lasers

    Science.gov (United States)

    Xu, Yuanli; Wu, Wenkai; Shi, Sucun; Duan, Lin; Chen, Gang; Wang, Baoxu; Song, Yugang; Liu, Huilin; Zhu, Mingzhi

    2016-10-01

    In ICF lasers, many independent laser beams are required to be positioned on target with a very high degree of accuracy during a shot. The target chamber provides a precision platform and datum reference for final optics assembly and target collimation and location system. The target chamber consists of shell with welded flanges, reinforced concrete pedestal, and lateral support structure. The field precision machining technology of target chamber in ICF lasers have been developed based on ShenGuangIII (SGIII). The same center of the target chamber is adopted in the process of design, fabrication, and alignment. The technologies of beam collimation and datum reference transformation are developed for the fabrication, positioning and adjustment of target chamber. A supporting and rotating mechanism and a special drilling machine are developed to bore the holes of ports. An adjustment mechanism is designed to accurately position the target chamber. In order to ensure the collimation requirements of the beam leading and focusing and the target positioning, custom-machined spacers are used to accurately correct the alignment error of the ports. Finally, this paper describes the chamber center, orientation, and centering alignment error measurements of SGIII. The measurements show the field precision machining of SGIII target chamber meet its design requirement. These information can be used on similar systems.

  2. Shrink-induced single-cell plastic microwell array.

    Science.gov (United States)

    Lew, Valerie; Nguyen, Diep; Khine, Michelle

    2011-12-01

    The ability to interrogate and track single cells over time in a high-throughput format would provide critical information for fundamental biological understanding of processes and for various applications, including drug screening and toxicology. We have developed an ultrarapid and simple method to create single-cell wells of controllable diameter and depth with commodity shrink-wrap film and tape. Using a programmable CO(2) laser, we cut hole arrays into the tape. The tape then serves as a shadow mask to selectively etch wells into commodity shrink-wrap film by O(2) plasma. When the shrink-wrap film retracts upon briefly heating, high-aspect plastic microwell arrays with diameters down to 20 μm are readily achieved. We calibrated the loading procedure with fluorescent microbeads. Finally, we demonstrate the utility of the wells by loading fluorescently labeled single human embryonic stem cells into the wells.

  3. Millisecond laser machining of transparent materials assisted by a nanosecond laser with different delays.

    Science.gov (United States)

    Pan, Yunxiang; Lv, Xueming; Zhang, Hongchao; Chen, Jun; Han, Bing; Shen, Zhonghua; Lu, Jian; Ni, Xiaowu

    2016-06-15

    A millisecond laser combined with a nanosecond laser was applied to machining transparent materials. The influences of delay between the two laser pulses on processing efficiencies and modified sizes were studied. In addition, a laser-supported combustion wave (LSCW) was captured during laser irradiation. An optimal delay corresponding to the highest processing efficiency was found for cone-shaped cavities. The modified size as well as the lifetime and intensity of the LSCW increased with the delay decreasing. Thermal cooperation effects of defects, overlapping effects of small modified sites, and thermal radiation from LSCW result in all the phenomena.

  4. Laser-error-correction control unit for machine tools

    Energy Technology Data Exchange (ETDEWEB)

    Burleson, R.R.

    1978-05-23

    An ultraprecision machining capability is needed for the laser fusion program. For this work, a precision air-bearing spindle has been mounted horizontally on a modified vertical column of a Moore Number 3 measuring machine base located in a development laboratory at the Oak Ridge Y-12 Plant. An open-loop control system previously installed on this machine was inadequate to meet the upcoming requirements since accuracy is limited to 0.5 ..mu..m by the errors in the machine's gears and leadscrew. A new controller was needed that could monitor the actual position of the machine and perform real-time error correction on the programmed tool path. It was necessary that this project: (1) attain an optimum tradeoff between hardware and software; (2) use a modular design for easy maintenance; (3) use a standard NC tape service; (4) drive the x and y axes with a positioning resolution of 5.08 nm and a feedback resolution of 10 nm; (5) drive the x and y axis motors at a velocity of 0.05 cm/sec in the contouring mode and 0.18 cm/sec in the positioning mode; (6) eliminate the possibility of tape-reader errors; and (7) allow editing of the part description data. The work that was done to develop and install the new machine controller is described.

  5. Pulse laser machining and particulate separation from high impact polystyrene

    Energy Technology Data Exchange (ETDEWEB)

    Arif, Saira; Kautek, Wolfgang, E-mail: wolfgang.kautek@univie.ac.at

    2014-01-01

    Opaque high impact polystyrene (HIPS) contaminated with graphite particles and poly(styrene-co-divinyl benzene) spheres can only be removed efficiently with nanosecond-pulsed laser radiation of 532 nm while the substrate is preserved. The destruction thresholds are 1–2 orders of magnitude lower than that of other common technical polymers. The inhomogeneously distributed polybutadiene composite component led to enhanced light scattering in the polystyrene matrix so that increased light absorption and energy density causes a comparatively low ablation threshold. Due to this fact there is advantageous potential for pulse laser machining at comparatively low fluences.

  6. Development of Laser Propelled ``Semi-Perpetual'' Rotary Machine

    Science.gov (United States)

    Gualini, M. M.; Khan, S. A.; Zulfiqar, K.

    2006-05-01

    This paper covers the initial work oriented to develop a semi-perpetual rotary machine propelled by laser ablation propulsion. The laser is equipped with a pulse repetition frequency tuned to the rotational frequency of the flying wheel. Purpose of this work is to establish the potentiality of a self-sustained closed system capable of generating kinetic rotary energy which can be exploited for traction of vehicles and production of electrical energy at very low cost. The work presented is in process of being patented.

  7. Study on the effect of thermal property of metals in ultrasonic-assisted laser machining

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Hu Seung; Kim, Gun Woo; Park, Jong Eun [Dept. of Mechanical Engineering, Korea Advanced Institute of Science and Technology, Daejeon (Korea, Republic of); Cho, Sung Hak; Yang, Min Yang; Park, Jong Kweon [Korea Institute of Machinery and Materials, Deajeon (Korea, Republic of)

    2015-08-15

    The laser machining process has been proposed as an advanced process for the selective fabrication of electrodes without a mask. In this study, we adapt laser machining to metals that have different thermal properties. Based on the results, the metals exhibit a different surface morphology, heat-affected zone (HAZ), and a recast layer around the machined surface according to their thermal conductivity, boiling point, and thermal diffusivity. Then, we apply ultrasonic-assisted laser machining to remove the recast layer. The ultrasonic-assisted laser machining exhibits a better surface quality in metals with higher diffusivity than those having lower diffusivity.

  8. Experience with laser microfabricated detectors at the University of Louisville

    CERN Document Server

    Pitts, W K

    2001-01-01

    We have designed, produced, and tested several different types of micropatterned gas proportional counters at the University of Louisville. A particular specialty has been the development and application of laser micromachining techniques to produce devices as the Microwell, GEM, and Microtube. Laser micromachining is a new technology with particular advantages for detector fabrication, including the ability to produce novel structures, machine wells in thick substrates, and produce detector arrays well suited to inclusion in modern microelectronics components. We report here the development of the Microwell detector and laser micromachining techniques for its production. First results are also presented for the Microtube detector, a device with a reduced anode formed as a tube extending into the center of the well.

  9. Fabrication of mitigation pits for improving laser damage resistance in dielectric mirrors by femtosecond laser machining

    Energy Technology Data Exchange (ETDEWEB)

    Wolfe, Justin E.; Qiu, S. Roger; Stolz, Christopher J.

    2011-03-20

    Femtosecond laser machining is used to create mitigation pits to stabilize nanosecond laser-induced damage in multilayer dielectric mirror coatings on BK7 substrates. In this paper, we characterize features and the artifacts associated with mitigation pits and further investigate the impact of pulse energy and pulse duration on pit quality and damage resistance. Our results show that these mitigation features can double the fluence-handling capability of large-aperture optical multilayer mirror coatings and further demonstrate that femtosecond laser macromachining is a promising means for fabricating mitigation geometry in multilayer coatings to increase mirror performance under high-power laser irradiation.

  10. Laser Beam MicroMachining (LBMM) - A review

    Science.gov (United States)

    Mishra, Sanjay; Yadava, Vinod

    2015-10-01

    The use of short and ultrashort laser pulses for micromachining application is an emerging technology. Laser Beam MicroMachining (LBMM) has revolutionized many industries by providing innovative solutions in numerous industrial micro-engineering applications. High-intensity short or ultrashort laser pulses are powerful thermal energy source for creating micro-features in wide range of materials. These lasers can precisely ablate various types of materials with little or no collateral damage. An overview of LBMM is given so that we can obtain a current view of capabilities and tradeoffs associated with LBMM of sub-micron size. The fundamental understanding of ultrafast laser ablation process has been elucidated and the various research activities performed with nanosecond, picosecond and femtosecond, lasers have been discussed to understand the physical mechanisms and the critical experimental parameters involved in the LBMM. The critical analysis of various theoretical and experimental models used to describe the performance analysis of LBMM has been elaborated so that we can identify the relevant principles underlying the process.

  11. Investigation of diffractive optical element femtosecond laser machining

    Energy Technology Data Exchange (ETDEWEB)

    Chabrol, Grégoire R., E-mail: g.chabrol@ecam-strasbourg.eu [ECAM Strasbourg-Europe, Espace Européen de l’entreprise, 2, rue de Madrid – 67300 SCHILTIGHEIM, CS. 20013, 67012 Strasbourg CEDEX (France); Laboratoire des Sciences de l’Ingénieur, de l’Informatique et de l’Imagerie (ICube), UDS-CNRS, UMR 7357, 300 bld Sébastien Brant, CS 10413, 67412 Illkirch cedex (France); Ciceron, Adline [ECAM Strasbourg-Europe, Espace Européen de l’entreprise, 2, rue de Madrid – 67300 SCHILTIGHEIM, CS. 20013, 67012 Strasbourg CEDEX (France); Laboratoire des Sciences de l’Ingénieur, de l’Informatique et de l’Imagerie (ICube), UDS-CNRS, UMR 7357, 300 bld Sébastien Brant, CS 10413, 67412 Illkirch cedex (France); Twardowski, Patrice; Pfeiffer, Pierre [Laboratoire des Sciences de l’Ingénieur, de l’Informatique et de l’Imagerie (ICube), UDS-CNRS, UMR 7357, 300 bld Sébastien Brant, CS 10413, 67412 Illkirch cedex (France); Télécom Physique Strasbourg – Pôle API – 300 Bd Sébastien Brant – CS 10413, Illkirch Graffenstaden F 67400 (France); and others

    2016-06-30

    Highlights: • A method for rapid manufacturing of optical diffractive element in BK7 is proposed. • A binary grating in BK7 was successfully machined by femtosecond laser pulses. • Process relying on nonlinear absorption in the dielectric due to photoionization. • The binary grating was analysed by SEM and interferometric microscopy. • Simulations by Fourier modal method supported the measured diffractive efficiency. - Abstract: This paper presents an explorative study on the machining of diffractive optical elements (DOEs) in transparent materials using a femtosecond laser source. A simple form of DOE, a binary phase grating with a period of 20.85 μm (σ = 0.5 μm), a groove depth and width of 0.7 μm (σ = 0.2 μm) and 8.8 μm (σ = 0.5 μm) respectively, was successfully machined in BK7. The topographic characteristics were measured by white light interferometry and scanning electron microscopy (SEM). The processing was carried out on high precision stages with an ultrafast fibre laser (350 fs) emitting a 343 nm pulse focused onto the sample with a stationary microscope objective. A diffracted efficiency of 27%, obtained with a spectro goniometer, was corroborated by the theoretical results obtained by the Fourier modal method (FMM), taking into account the measured topographic values. These encouraging results demonstrate that high-speed femtosecond laser manufacturing of DOE in bulk glasses can be achieved, opening the way to rapid prototyping of multi-layered-DOEs.

  12. [Application of laser induced breakdown spectroscopy (LIBS) to microdetection of Au film machining].

    Science.gov (United States)

    Yuan, Dong-qing; Zhou, Ming; Shen, Jian; Ren, Nai-fei; Cai, Lan

    2008-10-01

    Film micro-machining is a core in micro- and nano- technology, micro-electro-mechanical systems and photoelectron field. However, it is difficult to control the quality of machining in processing film. In the present paper the authors propose a method to solve this problem by using laser induced breakdown spectroscopy (LIBS). The authors investigated the relation between excitation condition and the quantity of plasma in the process of micro-machining by pulse laser. At low frequency (machining become true.

  13. Efficient production by laser materials processing integrated into metal cutting machines

    Science.gov (United States)

    Wiedmaier, M.; Meiners, E.; Dausinger, Friedrich; Huegel, Helmut

    1994-09-01

    Beam guidance of high power YAG-laser (cw, pulsed, Q-switched) with average powers up to 2000 W by flexible glass fibers facilitates the integration of the laser beam as an additional tool into metal cutting machines. Hence, technologies like laser cutting, joining, hardening, caving, structuring of surfaces and laser-marking can be applied directly inside machining centers in one setting, thereby reducing the flow of workpieces resulting in a lowering of costs and production time. Furthermore, materials with restricted machinability--especially hard materials like ceramics, hard metals or sintered alloys--can be shaped by laser-caving or laser assisted machining. Altogether, the flexibility of laser integrated machining centers is substantially increased or the efficiency of a production line is raised by time-savings or extended feasibilities with techniques like hardening, welding or caving.

  14. A Study on the Optimization Performance of Fireworks and Cuckoo Search Algorithms in Laser Machining Processes

    Science.gov (United States)

    Goswami, D.; Chakraborty, S.

    2014-11-01

    Laser machining is a promising non-contact process for effective machining of difficult-to-process advanced engineering materials. Increasing interest in the use of lasers for various machining operations can be attributed to its several unique advantages, like high productivity, non-contact processing, elimination of finishing operations, adaptability to automation, reduced processing cost, improved product quality, greater material utilization, minimum heat-affected zone and green manufacturing. To achieve the best desired machining performance and high quality characteristics of the machined components, it is extremely important to determine the optimal values of the laser machining process parameters. In this paper, fireworks algorithm and cuckoo search (CS) algorithm are applied for single as well as multi-response optimization of two laser machining processes. It is observed that although almost similar solutions are obtained for both these algorithms, CS algorithm outperforms fireworks algorithm with respect to average computation time, convergence rate and performance consistency.

  15. Laser machining for fabrication of targets used in the FIREX-I project

    Energy Technology Data Exchange (ETDEWEB)

    Fujimura, T; Nakai, M; Hayashi, N; Tanabe, M; Izawa, Y U; Homma, H; Nishimura, H; Norimatsu, T; Azechi, H [Institute of Laser Engineering (ILE), Osaka University, Osaka 565-0871 (Japan); Iwamoto, A; Nagai, K, E-mail: t-fujimura@ile.osaka-u.ac.j [National Institute for Fusion Science (NIFS), Toki, Gifu 509-5292 (Japan)

    2010-08-01

    This paper reports on way to fabricate a gas-tight targets dedicated for the first stage of Fast Ignition Realization Experiment (FIREX-I) at the Institute of Laser Engineering (ILE), Osaka University. It was found that a Ti;sapphire laser machining can be used to fabricate the target. The performance of the laser machining using a fs Ti;sapphire laser was examined on shell materials. The conditions for accurate machining were determined. Michelson interferometer with two different wavelengths which imitates a white light interferometer is an excellent tool for confirming the gas-tightness of the target after assembly.

  16. Microwell scaffolds for the extrahepatic transplantation of islets of Langerhans.

    Directory of Open Access Journals (Sweden)

    Mijke Buitinga

    Full Text Available Allogeneic islet transplantation into the liver has the potential to restore normoglycemia in patients with type 1 diabetes. However, the suboptimal microenvironment for islets in the liver is likely to be involved in the progressive islet dysfunction that is often observed post-transplantation. This study validates a novel microwell scaffold platform to be used for the extrahepatic transplantation of islet of Langerhans. Scaffolds were fabricated from either a thin polymer film or an electrospun mesh of poly(ethylene oxide terephthalate-poly(butylene terephthalate (PEOT/PBT block copolymer (composition: 4000PEOT30PBT70 and were imprinted with microwells, ∼400 µm in diameter and ∼350 µm in depth. The water contact angle and water uptake were 39±2° and 52.1±4.0 wt%, respectively. The glucose flux through electrospun scaffolds was three times higher than for thin film scaffolds, indicating enhanced nutrient diffusion. Human islets cultured in microwell scaffolds for seven days showed insulin release and insulin content comparable to those of free-floating control islets. Islet morphology and insulin and glucagon expression were maintained during culture in the microwell scaffolds. Our results indicate that the microwell scaffold platform prevents islet aggregation by confinement of individual islets in separate microwells, preserves the islet's native rounded morphology, and provides a protective environment without impairing islet functionality, making it a promising platform for use in extrahepatic islet transplantation.

  17. Advantages of Picosecond Laser Machining for Cutting-Edge Technologies

    Science.gov (United States)

    Moorhouse, C.

    The demand to reduce the size, weight and material cost of modern electronic devices results in a requirement for precision micromachining to aid product development. Examples include making smaller and more powerful smartphones with brighter displays, eliminating the requirement for post-process cleaning and machining the latest bio- absorbable medical stents. The pace of innovation in high-tech industries has led to ultrafast (picosecond) industrial lasers becoming an important tool for many applications and the high repetition rates now available help to meet industrial throughput levels. This is due to the unique operating regime (megawatts of peak power) enabling clean cutting and patterning of sensitive materials and thin films used in a number of novel devices and allows micromachining of wide bandgap, "difficult" materials such as glass.

  18. Microstructure & performance of laser cladding on pick surface of coal mining machine

    Institute of Scientific and Technical Information of China (English)

    SUN Hui-lai; ZHAO Fang-fang; ZHANG Shou-xin; QI Xiang-yang

    2006-01-01

    Laser cladding of 316 L steel powders on pick substrate of coal mining machine was conducted, and microstructure of laser cladding coating was analyzed. The micro-hardness of laser cladding coating was examined. The results show that microstructure of laser cladding zone is exiguous dentrite, and there are hard spots dispersible distribution in the laser cladding zone. Performances of erode-resistant, surface micro-hardness and wear-resistant are improved obviously.

  19. High-power picosecond laser drilling/machining of carbon fibre-reinforced polymer (CFRP) composites

    Science.gov (United States)

    Salama, A.; Li, L.; Mativenga, P.; Sabli, A.

    2016-02-01

    The large differences in physical and thermal properties of the carbon fibre-reinforced polymer (CFRP) composite constituents make laser machining of this material challenging. An extended heat-affected zone (HAZ) often occurs. The availability of ultrashort laser pulse sources such as picosecond lasers makes it possible to improve the laser machining quality of these materials. This paper reports an investigation on the drilling and machining of CFRP composites using a state-of-the-art 400 W picosecond laser system. Small HAZs (drilled on sample of 6 mm thickness, whereas no HAZ was seen below the top surface on the cut surfaces. Multiple ring material removal strategy was used. Furthermore, the effect of laser processing parameters such as laser power, scanning speed and repetition rate on HAZ sizes and ablation depth was investigated.

  20. An experimental investigation of pulsed laser-assisted machining of AISI 52100 steel

    Science.gov (United States)

    Panjehpour, Afshin; Soleymani Yazdi, Mohammad R.; Shoja-Razavi, Reza

    2014-11-01

    Grinding and hard turning are widely used for machining of hardened bearing steel parts. Laser-assisted machining (LAM) has emerged as an efficient alternative to grinding and hard turning for hardened steel parts. In most cases, continuous-wave lasers were used as a heat source to cause localized heating prior to material removal by a cutting tool. In this study, an experimental investigation of pulsed laser-assisted machining of AISI 52100 bearing steel was conducted. The effects of process parameters (i.e., laser mean power, pulse frequency, pulse energy, cutting speed and feed rate) on state variables (i.e., material removal temperature, specific cutting energy, surface roughness, microstructure, tool wear and chip formation) were investigated. At laser mean power of 425 W with frequency of 120 Hz and cutting speed of 70 m/min, the benefit of LAM was shown by 25% decrease in specific cutting energy and 18% improvement in surface roughness, as compared to those of the conventional machining. It was shown that at constant laser power, the increase of laser pulse energy causes the rapid increase in tool wear rate. Pulsed laser allowed efficient control of surface temperature and heat penetration in material removal region. Examination of the machined subsurface microstructure and microhardness profiles showed no change under LAM and conventional machining. Continuous chips with more uniform plastic deformation were produced in LAM.

  1. Microstructure and chemical bond evolution of diamond-like carbon films machined by femtosecond laser

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Jing; Wang, Chunhui [Science and Technology on Thermostructure Composite Materials Laboratory, Northwestern Polytechnical University, Xi’an 710072 (China); Liu, Yongsheng, E-mail: yongshengliu@nwpu.edu.cn [Science and Technology on Thermostructure Composite Materials Laboratory, Northwestern Polytechnical University, Xi’an 710072 (China); Cheng, Laifei [Science and Technology on Thermostructure Composite Materials Laboratory, Northwestern Polytechnical University, Xi’an 710072 (China); Li, Weinan [State Key Laboratory of Transient Optics and Photonics, Xi’an Institute of Optics and Precision Mechanics, Chinese Academy of Sciences, Xi’an 10068 (China); Zhang, Qing [Science and Technology on Thermostructure Composite Materials Laboratory, Northwestern Polytechnical University, Xi’an 710072 (China); Yang, Xiaojun [State Key Laboratory of Transient Optics and Photonics, Xi’an Institute of Optics and Precision Mechanics, Chinese Academy of Sciences, Xi’an 10068 (China)

    2015-06-15

    Highlights: • The machining depth was essentially proportional to the laser power. • The well patterned microgrooves and ripple structures with nanoparticles were formed distinctly in the channels. And the number of nanoparticles increased with the processing power as well. • It revealed a conversion from amorphous carbon to nanocrystalline graphite after laser treated with increasing laser power. • It showed that a great decrease of sp{sup 3}/sp{sup 2} after laser treatment. - Abstract: Femtosecond laser is of great interest for machining high melting point and hardness materials such as diamond-like carbon, SiC ceramic, et al. In present work, the microstructural and chemical bond evolution of diamond-like carbon films were investigated using electron microscopy and spectroscopy techniques after machined by diverse femtosecond laser power in air. The results showed the machining depth was essentially proportional to the laser power. The well patterned microgrooves and ripple structures with nanoparticles were formed distinctly in the channels. Considering the D and G Raman band parameters on the laser irradiation, it revealed a conversion from amorphous carbon to nanocrystalline graphite after laser treated with increasing laser power. X-ray photoelectron spectroscopy analysis showed a great decrease of sp{sup 3}/sp{sup 2} after laser treatment.

  2. Parametric modeling and optimization of laser scanning parameters during laser assisted machining of Inconel 718

    Science.gov (United States)

    Venkatesan, K.; Ramanujam, R.; Kuppan, P.

    2016-04-01

    This paper presents a parametric effect, microstructure, micro-hardness and optimization of laser scanning parameters (LSP) on heating experiments during laser assisted machining of Inconel 718 alloy. The laser source used for experiments is a continuous wave Nd:YAG laser with maximum power of 2 kW. The experimental parameters in the present study are cutting speed in the range of 50-100 m/min, feed rate of 0.05-0.1 mm/rev, laser power of 1.25-1.75 kW and approach angle of 60-90°of laser beam axis to tool. The plan of experiments are based on central composite rotatable design L31 (43) orthogonal array. The surface temperature is measured via on-line measurement using infrared pyrometer. Parametric significance on surface temperature is analysed using response surface methodology (RSM), analysis of variance (ANOVA) and 3D surface graphs. The structural change of the material surface is observed using optical microscope and quantitative measurement of heat affected depth that are analysed by Vicker's hardness test. The results indicate that the laser power and approach angle are the most significant parameters to affect the surface temperature. The optimum ranges of laser power and approach angle was identified as 1.25-1.5 kW and 60-65° using overlaid contour plot. The developed second order regression model is found to be in good agreement with experimental values with R2 values of 0.96 and 0.94 respectively for surface temperature and heat affected depth.

  3. Laser Machining Series. Educational Resources for the Machine Tool Industry. Course Syllabi, Instructor's Handbook, [and] Student Laboratory Manual.

    Science.gov (United States)

    Texas State Technical Coll. System, Waco.

    This package consists of course syllabi, an instructor's handbook, and a student laboratory manual for a 1-year vocational training program to prepare students for entry-level employment as laser machining technicians. The program was developed through a modification of the DACUM (Developing a Curriculum) technique. The course syllabi volume…

  4. An Investigation of Laser Assisted Machining of Al_2O_3 Particle Reinforced Aluminum Matrix Composite

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    The Al 2O 3 particles reinforced aluminum matrix composite (Al 2O 3p/Al) are more and more widely used for their excellent physical and chemical properties. However, their poor machinability leads to severe tool wear and bad machined surface. In this paper laser assisted machining is adopted in machining Al 2O 3p/Al composite and good result was obtained. The result of experiment shows in machining Al 2O 3p/Al composites the cutting force is reduced in 30%~50%, the tool wear is reduced in 20%~30% an...

  5. Ultrathin Polymer Films, Patterned Arrays, and Microwells

    Science.gov (United States)

    Yan, Mingdi

    2002-05-01

    The ability to control and tailor the surface and interface properties of materials is important in microelectronics, cell growth control, and lab-on-a-chip devices. Modification of material surfaces with ultrathin polymer films is attractive due to the availability of a variety of polymers either commercially or by synthesis. We have developed two approaches to the attachment of ultrathin polymer films on solid substrates. In the first method, a silane-functionalized perfluorophenyl azide (PFPA-silane) was synthesized and used to covalently immobilize polymer thin films on silicon wafers. Silanization of the wafer surface with the PFPA-silane introduced a monolayer of azido groups which in turn covalently attached the polymer film by way of photochemically initiated insertion reactions. The thickness of the film could be adjusted by the type and the molecular weight of the polymer. The method is versatile due to the general C-H and/or N-H insertion reactions of crosslinker; and therefore, no specific reactive functional groups on the polymers are required. Using this method, a new type of microwell array was fabricated from covalently immobilized polymer thin films on flat substrates. The arrays were characterized with AFM, XPS, and TOF-SIMS. The second method describes the attachment of polymer thin films on solid substrates via UV irradiation. The procedure consisted of spin-coating a polymer film and irradiating the film with UV light. Following solvent extraction, a thin film remained. The thickness of the film, from a few to over a hundred nanometers, was controlled by varying solution concentration and the molecular weight of the polymer.

  6. Method and apparatus for improving the quality and efficiency of ultrashort-pulse laser machining

    Science.gov (United States)

    Stuart, Brent C.; Nguyen, Hoang T.; Perry, Michael D.

    2001-01-01

    A method and apparatus for improving the quality and efficiency of machining of materials with laser pulse durations shorter than 100 picoseconds by orienting and maintaining the polarization of the laser light such that the electric field vector is perpendicular relative to the edges of the material being processed. Its use is any machining operation requiring remote delivery and/or high precision with minimal collateral dames.

  7. Experimental and theoretical study of the laser micro-machining of glass using high-repetition-rate ultrafast laser

    Science.gov (United States)

    Yashkir, Yuri; Liu, Qiang

    2006-04-01

    We present a systematic study of the ultrafast laser micro-machining of glass using a Ti:Spp laser with moderate pulse energy (<5 μJ) at a high repetition rate (50 kHz). Optimal conditions were identified for high resolution surface laser etching, and via drilling. Several practical applications were developed: glass templates for micro fluid diffraction devices, phase gratings for excimer laser projection techniques, micro fluid vertical channel-connectors, etc. It is demonstrated that the interaction of ultrafast laser pulses with glass combines several different processes (direct ablation, explosive material ejection, and thermal material modification). A dynamic numerical model was developed for this process. It was successfully used for modelling of laser micro-machining with arbitrary 3D translations of the target.

  8. On-line estimation of laser-drilled hole depth using a machine vision method.

    Science.gov (United States)

    Ho, Chao-Ching; He, Jun-Jia; Liao, Te-Ying

    2012-01-01

    The paper presents a novel method for monitoring and estimating the depth of a laser-drilled hole using machine vision. Through on-line image acquisition and analysis in laser machining processes, we could simultaneously obtain correlations between the machining processes and analyzed images. Based on the machine vision method, the depths of laser-machined holes could be estimated in real time. Therefore, a low cost on-line inspection system is developed to increase productivity. All of the processing work was performed in air under standard atmospheric conditions and gas assist was used. A correlation between the cumulative size of the laser-induced plasma region and the depth of the hole is presented. The result indicates that the estimated depths of the laser-drilled holes were a linear function of the cumulative plasma size, with a high degree of confidence. This research provides a novel machine vision-based method for estimating the depths of laser-drilled holes in real time.

  9. On-Line Estimation of Laser-Drilled Hole Depth Using a Machine Vision Method

    Directory of Open Access Journals (Sweden)

    Te-Ying Liao

    2012-07-01

    Full Text Available The paper presents a novel method for monitoring and estimating the depth of a laser-drilled hole using machine vision. Through on-line image acquisition and analysis in laser machining processes, we could simultaneously obtain correlations between the machining processes and analyzed images. Based on the machine vision method, the depths of laser-machined holes could be estimated in real time. Therefore, a low cost on-line inspection system is developed to increase productivity. All of the processing work was performed in air under standard atmospheric conditions and gas assist was used. A correlation between the cumulative size of the laser-induced plasma region and the depth of the hole is presented. The result indicates that the estimated depths of the laser-drilled holes were a linear function of the cumulative plasma size, with a high degree of confidence. This research provides a novel machine vision-based method for estimating the depths of laser-drilled holes in real time.

  10. Machining parameter optimization of C/SiC composites using high power picosecond laser

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Ruoheng; Li, Weinan [State Key Laboratory of Transient Optics and Photonics, Xi’an Institute of Optics and Precision Mechanics, Chinese Academy of Sciences, Xi’an, Shaanxi 10068 (China); Liu, Yongsheng, E-mail: yongshengliu@nwpu.edu.cn [Science and Technology on Thermostructure Composite Materials Laboratory, Northwestern Polytechnical University, Xi’an, Shaannxi 710072 (China); Wang, Chunhui; Wang, Jing [Science and Technology on Thermostructure Composite Materials Laboratory, Northwestern Polytechnical University, Xi’an, Shaannxi 710072 (China); Yang, Xiaojun [State Key Laboratory of Transient Optics and Photonics, Xi’an Institute of Optics and Precision Mechanics, Chinese Academy of Sciences, Xi’an, Shaanxi 10068 (China); Cheng, Laifei, E-mail: liuys99067@163.com [Science and Technology on Thermostructure Composite Materials Laboratory, Northwestern Polytechnical University, Xi’an, Shaannxi 710072 (China)

    2015-03-01

    Highlights: • We found that the helical line width and the helical line spacing, machining time and the scanning speed on the surface morphology of machined holes had remarkable effects on the qualities of micro-holes such as shape and depth. • The debris consisted of C, Si and O was observed on the machined surface. The Si−C bonds of the SiC matrix transformed into Si−O bonds after machined. - Abstract: Picosecond laser is an important machining technology for high hardness materials. In this paper, high power picosecond laser was utilized to drill micro-holes in C/SiC composites, and the effects of different processing parameters including the helical line width and spacing, machining time and scanning speed were discussed. To characterize the qualities of machined holes, scanning electron microscope (SEM) was used to analyze the surface morphology, energy dispersive spectroscopy (EDS) and X-ray photoelectric spectroscopy (XPS) were employed to describe the element composition change between the untreated and laser-treated area. The experimental results indicated that all parameters mentioned above had remarkable effects on the qualities of micro-holes such as shape and depth. Additionally, the debris consisted of C, Si and O was observed on the machined surface. The Si−C bonds of the SiC matrix transformed into Si−O bonds after machined. Furthermore, the physical process responsible for the mechanism of debris formation was discussed as well.

  11. Heat transfer model of semi-transparent ceramics undergoing laser-assisted machining

    Energy Technology Data Exchange (ETDEWEB)

    Pfefferkorn, F.E. [University of Wisconsin-Madison (United States). Department of Mechanical Engineering; Incropera, F.P. [University of Notre Dame, IN (United States). College of Engineering; Yung C. Shin [Purdue University, West Lafayette, IN (United States). School of Mechanical Engineering

    2005-05-01

    A three-dimensional, unsteady heat transfer model has been developed for predicting the temperature field in partially-stabilized zirconia (PSZ) undergoing laser-assisted machining. The semi-transparent PSZ is treated as optically thick within a spectral band from approximately 0.5 to 8 {mu}m. After comparing the diffusion approximation and the discrete ordinates method for predicting internal radiative transfer, suitability of the diffusion approximation is established from a comparison of model predictions with surface temperature measurements. The temperature predictions are in good agreement with measured values during machining. Parametric calculations reveal that laser power and feedrate have the greatest effect on machining temperatures. (author)

  12. Femtosecond laser ablation properties of transparent materials: impact of the laser process parameters on the machining throughput

    Science.gov (United States)

    Matylitsky, V. V.; Hendricks, F.; Aus der Au, J.

    2013-03-01

    High average power, high repetition rate femtosecond lasers with μJ pulse energies are increasingly used for bio-medical and material processing applications. With the introduction of femtosecond laser systems such as the SpiritTM platform developed by High Q Lasers and Spectra-Physics, micro-processing of solid targets with femtosecond laser pulses have obtained new perspectives for industrial applications [1]. The unique advantage of material processing with subpicosecond lasers is efficient, fast and localized energy deposition, which leads to high ablation efficiency and accuracy in nearly all kinds of solid materials. The study on the impact of the laser processing parameters on the removal rate for transparent substrate using femtosecond laser pulses will be presented. In particular, examples of micro-processing of poly-L-lactic acid (PLLA) - bio-degradable polyester and XensationTM glass (Schott) machined with SpiritTM ultrafast laser will be shown.

  13. The laser interferometer system for the large optics diamond turning machine

    Energy Technology Data Exchange (ETDEWEB)

    Baird, E D; Donaldson, R R; Patterson, S R

    1999-06-29

    The purpose of this report is to describe the Laser Interferometer System designed for the Large Optics Diamond Turning Machine (LODTM). To better understand the laser interferometer system, it is useful to begin with an overview of the LODTM metrology system.

  14. Repurposing mainstream CNC machine tools for laser-based additive manufacturing

    Science.gov (United States)

    Jones, Jason B.

    2016-04-01

    The advent of laser technology has been a key enabler for industrial 3D printing, known as Additive Manufacturing (AM). Despite its commercial success and unique technical capabilities, laser-based AM systems are not yet able to produce parts with the same accuracy and surface finish as CNC machining. To enable the geometry and material freedoms afforded by AM, yet achieve the precision and productivity of CNC machining, hybrid combinations of these two processes have started to gain traction. To achieve the benefits of combined processing, laser technology has been integrated into mainstream CNC machines - effectively repurposing them as hybrid manufacturing platforms. This paper reviews how this engineering challenge has prompted beam delivery innovations to allow automated changeover between laser processing and machining, using standard CNC tool changers. Handling laser-processing heads using the tool changer also enables automated change over between different types of laser processing heads, further expanding the breadth of laser processing flexibility in a hybrid CNC. This paper highlights the development, challenges and future impact of hybrid CNCs on laser processing.

  15. Comparison of preparation speed of Er:YAG laser and conventional drilling machine

    Science.gov (United States)

    Jelinkova, Helena; Dostalova, Tatjana; Dolezalova, Libuse; Krejsa, Otakar; Hamal, Karel; Kubelka, Jiri; Prochazka, Stanislav

    1997-05-01

    Clinical tests of the caries treatment with a Er:YAG laser system have been very promising. The problem of the Er:YAG laser drilling machine is the speed of preparation. It is not possible to increase the laser energy and repetition rate because this process is directly connected with temperature elevation. Therefore attention has been paid to define the differences between the classical and the laser drilling effect with a safe but effective laser energy and repetition rate. For the experiment, an Er:YAG laser drilling machine with an articulated arm was designed. Thirty samples of extracted human teeth were cut by both this system and classical drilling machine. The circumference, area and structure of surface sections were observed and analyzed. From the comparison of the measured time of preparation significant differences followed from the time of preparation. The time of preparation related to 1 mm2 of the cut surface was 5.42 sec for the Er:YAG laser machine and 0.66 sec for the classical method. From this comparison it follows that the laser system is 8 times slower than the classical preparation technique. In both cases the roughness of the surface analyzed by SCAN was found similar. Also, there were no differences between the distribution of the elements, especially calcium and phosphorus.

  16. pH-triggered drug release from biodegradable microwells for oral drug delivery

    DEFF Research Database (Denmark)

    Nielsen, Line Hagner; Nagstrup, Johan; Gordon, Sarah;

    2015-01-01

    Microwells fabricated from poly-L-lactic acid (PLLA) were evaluated for their application as an oral drug delivery system using the amorphous sodium salt of furosemide (ASSF) as a model drug. Hot embossing of PLLA resulted in fabrication of microwells with an inner diameter of 240 μm and a height...... of microwell cavities with an Eudragit® layer prevented drug release in biorelevant gastric medium. An immediate release of the ASSF from coated microwells was observed in the intestinal medium. This pH-triggered release behavior demonstrates the future potential of PLLA microwells as a site-specific oral drug...

  17. Development of a Flexible Laser Hardening & Machining Center and Proof of Concept on C-45 Steel

    Science.gov (United States)

    Bouquet, Jan; Van Camp, Dries; Vanhove, Hans; Clijsters, Stijn; Amirahmad, Mohammadi; Lauwers, Bert

    The production of hardened precision parts is conventionally done in 3 steps. Rough machining of a workpiece in soft stage is followed by a hardening step, usually a batch process, and finalized by a hard machining finishing step. To omit the inevitable time delay and loss of accuracy because of part re-clamping, these steps should be incorporated within one flexible machining center. This paper describes the development of this machining center which allowsmachining and laser hardening in one setup, followed by a proof of concept for hardening C45 steel on this setup.

  18. The laser micro-machining system for diamond anvil cell experiments and general precision machining applications at the High Pressure Collaborative Access Team.

    Science.gov (United States)

    Hrubiak, Rostislav; Sinogeikin, Stanislav; Rod, Eric; Shen, Guoyin

    2015-07-01

    We have designed and constructed a new system for micro-machining parts and sample assemblies used for diamond anvil cells and general user operations at the High Pressure Collaborative Access Team, sector 16 of the Advanced Photon Source. The new micro-machining system uses a pulsed laser of 400 ps pulse duration, ablating various materials without thermal melting, thus leaving a clean edge. With optics designed for a tight focus, the system can machine holes any size larger than 3 μm in diameter. Unlike a standard electrical discharge machining drill, the new laser system allows micro-machining of non-conductive materials such as: amorphous boron and silicon carbide gaskets, diamond, oxides, and other materials including organic materials such as polyimide films (i.e., Kapton). An important feature of the new system is the use of gas-tight or gas-flow environmental chambers which allow the laser micro-machining to be done in a controlled (e.g., inert gas) atmosphere to prevent oxidation and other chemical reactions in air sensitive materials. The gas-tight workpiece enclosure is also useful for machining materials with known health risks (e.g., beryllium). Specialized control software with a graphical interface enables micro-machining of custom 2D and 3D shapes. The laser-machining system was designed in a Class 1 laser enclosure, i.e., it includes laser safety interlocks and computer controls and allows for routine operation. Though initially designed mainly for machining of the diamond anvil cell gaskets, the laser-machining system has since found many other micro-machining applications, several of which are presented here.

  19. The laser micro-machining system for diamond anvil cell experiments and general precision machining applications at the High Pressure Collaborative Access Team

    Energy Technology Data Exchange (ETDEWEB)

    Hrubiak, Rostislav; Sinogeikin, Stanislav; Rod, Eric; Shen, Guoyin [High Pressure Collaborative Access Team, Geophysical Laboratory, Carnegie Institution of Washington, Argonne, Illinois 60439 (United States)

    2015-07-15

    We have designed and constructed a new system for micro-machining parts and sample assemblies used for diamond anvil cells and general user operations at the High Pressure Collaborative Access Team, sector 16 of the Advanced Photon Source. The new micro-machining system uses a pulsed laser of 400 ps pulse duration, ablating various materials without thermal melting, thus leaving a clean edge. With optics designed for a tight focus, the system can machine holes any size larger than 3 μm in diameter. Unlike a standard electrical discharge machining drill, the new laser system allows micro-machining of non-conductive materials such as: amorphous boron and silicon carbide gaskets, diamond, oxides, and other materials including organic materials such as polyimide films (i.e., Kapton). An important feature of the new system is the use of gas-tight or gas-flow environmental chambers which allow the laser micro-machining to be done in a controlled (e.g., inert gas) atmosphere to prevent oxidation and other chemical reactions in air sensitive materials. The gas-tight workpiece enclosure is also useful for machining materials with known health risks (e.g., beryllium). Specialized control software with a graphical interface enables micro-machining of custom 2D and 3D shapes. The laser-machining system was designed in a Class 1 laser enclosure, i.e., it includes laser safety interlocks and computer controls and allows for routine operation. Though initially designed mainly for machining of the diamond anvil cell gaskets, the laser-machining system has since found many other micro-machining applications, several of which are presented here.

  20. The laser micro-machining system for diamond anvil cell experiments and general precision machining applications at the High Pressure Collaborative Access Team

    Science.gov (United States)

    Hrubiak, Rostislav; Sinogeikin, Stanislav; Rod, Eric; Shen, Guoyin

    2015-07-01

    We have designed and constructed a new system for micro-machining parts and sample assemblies used for diamond anvil cells and general user operations at the High Pressure Collaborative Access Team, sector 16 of the Advanced Photon Source. The new micro-machining system uses a pulsed laser of 400 ps pulse duration, ablating various materials without thermal melting, thus leaving a clean edge. With optics designed for a tight focus, the system can machine holes any size larger than 3 μm in diameter. Unlike a standard electrical discharge machining drill, the new laser system allows micro-machining of non-conductive materials such as: amorphous boron and silicon carbide gaskets, diamond, oxides, and other materials including organic materials such as polyimide films (i.e., Kapton). An important feature of the new system is the use of gas-tight or gas-flow environmental chambers which allow the laser micro-machining to be done in a controlled (e.g., inert gas) atmosphere to prevent oxidation and other chemical reactions in air sensitive materials. The gas-tight workpiece enclosure is also useful for machining materials with known health risks (e.g., beryllium). Specialized control software with a graphical interface enables micro-machining of custom 2D and 3D shapes. The laser-machining system was designed in a Class 1 laser enclosure, i.e., it includes laser safety interlocks and computer controls and allows for routine operation. Though initially designed mainly for machining of the diamond anvil cell gaskets, the laser-machining system has since found many other micro-machining applications, several of which are presented here.

  1. Numerical investigation on machining glass with CO2lasers

    Institute of Scientific and Technical Information of China (English)

    Junke JIAO; Xinbing WANG

    2009-01-01

    When a glass substrate was irradiated by three different temporal shapes of laser sources, namely, linetime-shape laser, triangle-time-shape laser, and parabolatime-shape laser, the mathematical models were proposed,and the temperature distribution and the resulting thermal stress were calculated by the finite-element-method (FEM)software ANSYS.With these three types of lasers having the same output laser energy, the resulting thermal stress induced in the glass substrate was analyzed.The results showed that, with the same output laser energy, the thermal stress produced in glass heated by line-time-shape laser is higher than that produced in glass heated by the other two shapes of lasers.

  2. A prototypic system of parallel electrophoresis in multiple capillaries coupled with microwell arrays.

    Science.gov (United States)

    Su, Jing; Ren, Kangning; Dai, Wen; Zhao, Yihua; Zhou, Jianhua; Wu, Hongkai

    2011-11-01

    We present a microfluidic system that can be directly coupled with microwell array and perform parallel electrophoresis in multiple capillaries simultaneously. The system is based on an array of glass capillaries, fixed in a polydimethylsiloxane (PDMS) microfluidic scaffold, with one end open for interfacing with microwells. In this capillary array, every two adjacent capillaries act as a pair to be coupled with one microwell; samples in the microwells are introduced and separated by simply applying voltage between two electrodes that are placed at the other ends of capillaries; thus no complicated circuit design is required. We evaluate the performance of this system and perform multiple CE with direct sample introduction from microwell array. Also with this system, we demonstrate the analysis of cellular contents of cells lysed in a microwell array. Our results show that this prototypic system is a promising platform for high-throughput analysis of samples in microwell arrays.

  3. Novel laser machining of optical fibers for long cavities with low birefringence

    CERN Document Server

    Takahashi, Hiroki; Orucevic, Fedja; Noguchi, Atsushi; Kassa, Ezra; Keller, Matthias

    2015-01-01

    We present a novel method of machining optical fiber surfaces with a CO${}_2$ laser for use in Fiber-based Fabry-Perot Cavities (FFPCs). Previously FFPCs were prone to large birefringence and limited to relatively short cavity lengths ($\\le$ 200 $\\mu$m). These characteristics hinder their use in some applications such as cavity quantum electrodynamics with trapped ions. We optimized the laser machining process to produce large, uniform surface structures. This enables the cavities to achieve high finesse even for long cavity lengths. By rotating the fibers around their axis during the laser machining process the asymmetry resulting from the laser's transverse mode profile is eliminated. Consequently we are able to fabricate fiber mirrors with a high degree of rotational symmetry, leading to remarkably low birefringence. Through measurements of the cavity finesse over a range of cavity lengths and the polarization dependence of the cavity linewidth, we confirmed the quality of the produced fiber mirrors for us...

  4. KrF excimer laser precision machining of hard and brittle ceramic biomaterials.

    Science.gov (United States)

    Huang, Yao-Xiong; Lu, Jian-Yi; Huang, Jin-Xia

    2014-06-01

    KrF excimer laser precision machining of porous hard-brittle ceramic biomaterials was studied to find a suitable way of machining the materials into various desired shapes and sizes without distorting their intrinsic structure and porosity. Calcium phosphate glass ceramics (CPGs) and hydroxyapatite (HA) were chosen for the study. It was found that KrF excimer laser can cut both CPGs and HA with high efficiency and precision. The ablation rates of CPGs and HA are respectively 0.081 µm/(pulse J cm(-2)) and 0.048 µm/(pulse  J cm(-2)), while their threshold fluences are individually 0.72 and 1.5 J cm(-2). The cutting quality (smoothness of the cut surface) is a function of laser repetition rate and cutting speed. The higher the repetition rate and lower the cutting speed, the better the cutting quality. A comparison between the cross sections of CPGs and HA cut using the excimer laser and using a conventional diamond cutting blade indicates that those cut by the excimer laser could retain their intrinsic porosity and geometry without distortion. In contrast, those cut by conventional machining had distorted geometry and most of their surface porosities were lost. Therefore, when cutting hard-brittle ceramic biomaterials to prepare scaffold and implant or when sectioning them for porosity evaluation, it is better to choose KrF excimer laser machining.

  5. Femtosecond versus picosecond laser machining of nano-gratings and micro-channels in silica glass.

    Science.gov (United States)

    Corbari, Costantino; Champion, Audrey; Gecevičius, Mindaugas; Beresna, Martynas; Bellouard, Yves; Kazansky, Peter G

    2013-02-25

    The ability of 8 picosecond pulse lasers for three dimensional direct-writing in the bulk of transparent dielectrics is assessed through a comparative study with a femtosecond laser delivering 600 fs pulses. The comparison addresses two main applications: the fabrication of birefringent optical elements and two-step machining by laser exposure and post-processing by chemical etching. Formation of self-organized nano-gratings in glass by ps-pulses is demonstrated. Differential etching between ps-laser exposed regions and unexposed silica is observed. Despite attaining values of retardance (>100 nm) and etching rate (2 μm/min) similar to fs pulses, ps pulses are found unsuitable for bulk machining in silica glass primarily due to the build-up of a stress field causing scattering, cracks and non-homogeneous etching. Additionally, we show that the so-called "quill-effect", that is the dependence of the laser damage from the direction of writing, occurs also for ps-pulse laser machining. Finally, an opposite dependence of the retardance from the intra-pulse distance is observed for fs- and ps-laser direct writing.

  6. Laser-assisted machining process simulation for precision mould/die manufacturing

    Directory of Open Access Journals (Sweden)

    Zeng Quanren

    2015-01-01

    Full Text Available Laser-assisted machining (LAM is a kind of thermally assisted manufacturing process which preheats workpiece material with a highly-localized laser beam and then is followed by a conventional machining operation. It could greatly improve the machinability and gives better machining quality, especially suitable for hard-to-cut materials such as superalloys, tool steels. For manufacturing the high-precision moulds/dies that could fabricate micro and precision components, the thermal assistance at the local cutting zone, will help to lower the cutting force and consequently improve the internal surface quality of the machined moulds/dies. In this paper, a numerical study of the laser-assisted cutting of plastic mould steel NAK80 is reported. The simulation of LAM of NAK80 is realized by combining two procedures: simulation of moving laser heat source applied on the local surface of workpiece which causes the corresponding temperature field arise and material soften, and simulation of the subsequent cutting processes. This research will offer the die/mould manufacturers a more efficient planning tool for the fabrication of the micro, precision dies/moulds of high surface quality, and hence, for forming the high-quality micro components as well as for longer die/mould life.

  7. Surface roughness analysis after machining of direct laser deposited tungsten carbide

    Science.gov (United States)

    Wojciechowski, S.; Twardowski, P.; Chwalczuk, T.

    2014-03-01

    In this paper, an experimental surface roughness analysis in machining of tungsten carbide is presented. The tungsten carbide was received using direct laser deposition technology (DLD). Experiments carried out included milling of tungsten carbide samples using monolithic torus cubic boron nitride (CBN) tool and grinding with the diamond cup wheel. The effect of machining method on the generated surface topography was analysed. The 3D surface topographies were measured using optical surface profiler. The research revealed, that surface roughness generated after the machining of tungsten carbide is affected by feed per tooth (fz) value related to kinematic-geometric projection only in a minor extent. The main factor affecting machined surface roughness is the occurrence of micro grooves and protuberances on the machined surface, as well as other phenomena connected, inter alia, with the mechanism for material removal.

  8. Picosecond Laser Machining of Deep Holes in Silicon Infi ltrated Silicon Carbide Ceramics

    Institute of Scientific and Technical Information of China (English)

    ZHANG Qing; WANG Chunhui; LIU Yongsheng; ZHANG Litong; CHENG Guanghua

    2015-01-01

    Silicon infi ltrated silicon carbide (Si-SiC) ceramics, as high hardness materials, are diffi cult to machine, especially drilling micro-holes. In this study, the interaction of picosecond laser pulses (1 ps at 1 030 nm) with Si-SiC ceramics was investigated. Variations of the diameter and depth of circular holes with the growth of the laser energy density were obtained. The results indicate that the increase of machining depth follows a nonlinear relation with the increasing of laser energy density, while the diameter has little change with that. Moreover, it is found that some debris and particles are deposited around and inside the holes and waviness is in the entrance and at walls of the holes after laser processing.

  9. An improved brine shrimp larvae lethality microwell test method.

    Science.gov (United States)

    Zhang, Yi; Mu, Jun; Han, Jinyuan; Gu, Xiaojie

    2012-01-01

    This article described an improved brine shrimp larvae lethality microwell test method. A simply designed connecting vessel with alternative photoperiod was used to culture and collect high yield of active Artemia parthenogenetica nauplii for brine shrimp larvae lethality microwell test. Using this method, pure A. parthenogenetica nauplii suspension was easily cultured and harvested with high density about 100-150 larvae per milliliter and the natural mortality was reduced to near zero by elimination of unnecessary artificial disturbance. And its sensitivity was validated by determination of LC(50)-24 h of different reference toxicants including five antitumor agents, two pesticides, three organic pollutants, and four heavy metals salts, most of which exhibited LC(50)-24 h between 0.07 and 58.43 mg/L except for bleomycin and mitomycin C with LC(50)-24 h over 300 mg/L.

  10. pH-triggered drug release from biodegradable microwells for oral drug delivery

    DEFF Research Database (Denmark)

    Nielsen, Line Hagner; Nagstrup, Johan; Gordon, Sarah

    2015-01-01

    of 100 μm. The microwells were filled with ASSF using a modified screen printing technique, followed by coating of the microwell cavities with a gastroresistant lid of Eudragit® L100. The release behavior of ASSF from the coated microwells was investigated using a μ-Diss profiler and a UV imaging system......, and under conditions simulating the changing environment of the gastrointestinal tract. Biorelevant gastric medium (pH 1.6) was employed, after which a change to biorelevant intestinal release medium (pH 6.5) was carried out. Both μ-Diss profiler and UV imaging release experiments showed that sealing...... of microwell cavities with an Eudragit® layer prevented drug release in biorelevant gastric medium. An immediate release of the ASSF from coated microwells was observed in the intestinal medium. This pH-triggered release behavior demonstrates the future potential of PLLA microwells as a site-specific oral drug...

  11. The study on force, surface integrity, tool life and chip on laser assisted machining of inconel 718 using Nd:YAG laser source.

    Science.gov (United States)

    Venkatesan, K

    2017-07-01

    Inconel 718, a high-temperature alloy, is a promising material for high-performance aerospace gas turbine engines components. However, the machining of the alloy is difficult owing to immense shear strength, rapid work hardening rate during turning, and less thermal conductivity. Hence, like ceramics and composites, the machining of this alloy is considered as difficult-to-turn materials. Laser assisted turning method has become a promising solution in recent years to lessen cutting stress when materials that are considered difficult-to-turn, such as Inconel 718 is employed. This study investigated the influence of input variables of laser assisted machining on the machinability aspect of the Inconel 718. The comparison of machining characteristics has been carried out to analyze the process benefits with the variation of laser machining variables. The laser assisted machining variables are cutting speeds of 60-150 m/min, feed rates of 0.05-0.125 mm/rev with a laser power between 1200 W and 1300 W. The various output characteristics such as force, roughness, tool life and geometrical characteristic of chip are investigated and compared with conventional machining without application of laser power. From experimental results, at a laser power of 1200 W, laser assisted turning outperforms conventional machining by 2.10 times lessening in cutting force, 46% reduction in surface roughness as well as 66% improvement in tool life when compared that of conventional machining. Compared to conventional machining, with the application of laser, the cutting speed of carbide tool has increased to a cutting condition of 150 m/min, 0.125 mm/rev. Microstructural analysis shows that no damage of the subsurface of the workpiece.

  12. The study on force, surface integrity, tool life and chip on laser assisted machining of inconel 718 using Nd:YAG laser source

    Directory of Open Access Journals (Sweden)

    K. Venkatesan

    2017-07-01

    Full Text Available Inconel 718, a high-temperature alloy, is a promising material for high-performance aerospace gas turbine engines components. However, the machining of the alloy is difficult owing to immense shear strength, rapid work hardening rate during turning, and less thermal conductivity. Hence, like ceramics and composites, the machining of this alloy is considered as difficult-to-turn materials. Laser assisted turning method has become a promising solution in recent years to lessen cutting stress when materials that are considered difficult-to-turn, such as Inconel 718 is employed. This study investigated the influence of input variables of laser assisted machining on the machinability aspect of the Inconel 718. The comparison of machining characteristics has been carried out to analyze the process benefits with the variation of laser machining variables. The laser assisted machining variables are cutting speeds of 60–150 m/min, feed rates of 0.05–0.125 mm/rev with a laser power between 1200 W and 1300 W. The various output characteristics such as force, roughness, tool life and geometrical characteristic of chip are investigated and compared with conventional machining without application of laser power. From experimental results, at a laser power of 1200 W, laser assisted turning outperforms conventional machining by 2.10 times lessening in cutting force, 46% reduction in surface roughness as well as 66% improvement in tool life when compared that of conventional machining. Compared to conventional machining, with the application of laser, the cutting speed of carbide tool has increased to a cutting condition of 150 m/min, 0.125 mm/rev. Microstructural analysis shows that no damage of the subsurface of the workpiece.

  13. Deformable L-shaped microwell array for trapping pairs of heterogeneous cells

    Science.gov (United States)

    Lee, Gi-Hun; Kim, Sung-Hwan; Kang, AhRan; Takayama, Shuichi; Lee, Sang-Hoon; Park, Joong Yull

    2015-03-01

    To study cell-to-cell interactions, there has been a continuous demand on developing microsystems for trapping pairs of two different cells in microwell arrays. Here, we propose an L-shaped microwell (L-microwell) array that relies on the elasticity of a polydimethylsiloxane (PDMS) substrate for trapping and pairing heterogeneous cells. We designed an L-microwell suitable for trapping single cell in each branch via stretching/releasing the PDMS substrate, and also performed 3D time-dependent diffusion simulations to visualize how cell-secreted molecules diffuse in the L-microwell and communicate with the partner cell. The computational results showed that the secreted molecule first contacted the partner cell after 35 min, and the secreted molecule fully covered the partner cell in 4 h (when referenced to 10% of the secreted molecular concentration). The molecules that diffused to the outside of the L-microwell were significantly diluted by the bulk solution, which prevented unwanted cellular communication between neighboring L-microwells. We produced over 5000 cell pairs in one 2.25 cm2 array with about 30 000 L-microwells. The proposed L-microwell array offers a versatile and convenient cell pairing method to investigate cell-to-cell interactions in, for example, cell fusion, immune reactions, and cancer metastasis.

  14. SERS based immuno-microwell arrays for multiplexed detection of foodborne pathogenic bacteria

    Science.gov (United States)

    Sun, Jian; Hankus, Mikella E.; Cullum, Brian M.

    2009-05-01

    A novel surface enhanced Raman scattering (SERS)-based immuno-microwell array has been developed for multiplexed detection of foodborne pathogenic bacteria. The immuno-microwell array was prepared by immobilizing the optical addressable immunomagnetic beads (IMB) into the microwell array on one end of a fiber optic bundle. The IMBs, magnetic beads coated with specific antibody to specific bacteria, were used for immunomagnetic separation (IMS) of corresponding bacteria. The magnetic separation by the homemade magnetic separation system was evaluated in terms of the influences of several important parameters including the beads concentration, the sample volume and the separation time. IMS separation efficiency of the model bacteria E.coli O157:H7 was 63% in 3 minutes. The microwell array was fabricated on hydrofluoric acid etched end of a fiber optic bundle containing 30,000 fiber elements. After being coated with silver, the microwell array was used as a uniform SERS substrate with the relative standard deviation of the SERS enhancement across the microwell array < 2% and the enhancement factor as high as 2.18 x 107. The antibody modified microwell array was prepared for bacteria immobilization into the microwell array, which was characterized by a sandwich immunoassay. To demonstrate the potential of multiplexed SERS detection with the immuno-microwell array, the SERS spectra of different Raman dye labeled magnetic beads as well as mixtures were measured on the mircrowell array. In bead mixture, different beads were identified by the characteristic SERS bands of the corresponding Raman label.

  15. Machining parameter optimization of C/SiC composites using high power picosecond laser

    Science.gov (United States)

    Zhang, Ruoheng; Li, Weinan; Liu, Yongsheng; Wang, Chunhui; Wang, Jing; Yang, Xiaojun; Cheng, Laifei

    2015-03-01

    Picosecond laser is an important machining technology for high hardness materials. In this paper, high power picosecond laser was utilized to drill micro-holes in C/SiC composites, and the effects of different processing parameters including the helical line width and spacing, machining time and scanning speed were discussed. To characterize the qualities of machined holes, scanning electron microscope (SEM) was used to analyze the surface morphology, energy dispersive spectroscopy (EDS) and X-ray photoelectric spectroscopy (XPS) were employed to describe the element composition change between the untreated and laser-treated area. The experimental results indicated that all parameters mentioned above had remarkable effects on the qualities of micro-holes such as shape and depth. Additionally, the debris consisted of C, Si and O was observed on the machined surface. The Sisbnd C bonds of the SiC matrix transformed into Sisbnd O bonds after machined. Furthermore, the physical process responsible for the mechanism of debris formation was discussed as well.

  16. Industrial femtosecond lasers for machining of heat-sensitive polymers (Conference Presentation)

    Science.gov (United States)

    Hendricks, Frank; Bernard, Benjamin; Matylitsky, Victor V.

    2017-03-01

    Heat-sensitive materials, such as polymers, are used increasingly in various industrial sectors such as medical device manufacturing and organic electronics. Medical applications include implantable devices like stents, catheters and wires, which need to be structured and cut with minimum heat damage. Also the flat panel display market moves from LCD displays to organic LED (OLED) solutions, which utilize heat-sensitive polymer substrates. In both areas, the substrates often consist of multilayer stacks with different types of materials, such as metals, dielectric layers and polymers with different physical characteristic. The different thermal behavior and laser absorption properties of the materials used makes these stacks difficult to machine using conventional laser sources. Femtosecond lasers are an enabling technology for micromachining of these materials since it is possible to machine ultrafine structures with minimum thermal impact and very precise control over material removed. An industrial femtosecond Spirit HE laser system from Spectra-Physics with pulse duration 120 μJ and average output powers of >16 W is an ideal tool for industrial micromachining of a wide range of materials with highest quality and efficiency. The laser offers process flexibility with programmable pulse energy, repetition rate, and pulse width. In this paper, we provide an overview of machining heat-sensitive materials using Spirit HE laser. In particular, we show how the laser parameters (e.g. laser wavelength, pulse duration, applied energy and repetition rate) and the processing strategy (gas assisted single pass cut vs. multi-scan process) influence the efficiency and quality of laser processing.

  17. Laser and focused ion beam combined machining for micro dies.

    Science.gov (United States)

    Yoshida, Y; Okazaki, W; Uchida, T

    2012-02-01

    We have developed a laser and focused ion beam (FIB) compound process for press mold dies of a micro lens array (MLA) and a micro needle array (MNA) in a glassy carbon (GC). The press mold die of the MLA was roughly fabricated by UV-YAG laser. After this process, we finished this surface by scanning FIB. As a result, higher accuracy and good roughness of surface profile can be realized. An optical glass is used to confirm the shape of lens. Moreover, we fabricated 6 × 6 through-holes in the GC by the spiral drilling in addition to the focus position movement of the UV laser for press mold die of the MNA. After the FIB process, we were able to make the needle die of surface and hole wall roughness less than 0.9 μm. A silicon rubber is used to confirm the shape of the holes.

  18. Experimental and theoretical evaluation of the laser-assisted machining of silicon nitride

    Science.gov (United States)

    Rozzi, Jay Christopher

    This study focused on the experimental and theoretical evaluation of the laser assisted machining (LAM) of silicon nitride ceramics. A laser assisted machining facility was constructed whose main components consist of a COsb2 laser and a CNC lathe. Surface temperature histories were first measured and compared to a transient, three-dimensional numerical simulation for a rotating silicon nitride workpiece heated by a translating laser for ranges of the workpiece rotational and laser-translation speeds, as well as the laser beam diameter and power. Excellent agreement was obtained between the experimental and predicted temperature histories. Laser assisted machining experiments on silicon nitride ceramic workpieces were completed for a wide range of operating conditions. Data for cutting forces and surface temperature histories illustrated that the lower bound for the avoidance of cutting tool and/or workpiece fracture for LAM is defined by the YSiAlON glass transition temperature (920-970sp°C). As temperatures near the cutting tool increase to values above the glass transition temperature range, the glassy phase softened, facilitating plastic deformation and, correspondingly, the production of semi-continuous or continuous chips. The silicon nitride machined workpiece surface roughness (Rsb{a}=0.39\\ mum) for LAM at the nominal operating condition was nearly equivalent to a value associated with the grinding of silicon nitride using a diamond wheel (Rsb{a}=0.2\\ mum). By examining the machined surfaces and chips, it was shown that LAM does not produce detectable sub-surface cracking or significant silicon nitride microstructure alteration, respectively. A transient, three-dimensional numerical heat transfer model of laser assisted machining was constructed, which includes a preheat phase and material removal, with the associated changes in the workplace geometry. Excellent agreement was obtained between the measured and predicted temperature histories. The strong

  19. Influence of the direction of selective laser sintering on machinability of parts from 316L steel

    Science.gov (United States)

    Alexeev, V. P.; Balyakin, A. V.; Khaimovich, A. I.

    2017-02-01

    This work presents the results of research of the impact of layer-by-layer growing of workpieces made of 316L steel on their machinability. The results of determination of residual stresses and measurement of hardness of the workpieces grown have been demonstrated. A series of experimental studies has been performed in order to determine the cutting force which occurs in the process of machining. The microstructure of the workpieces grown has been examined. It has been shown that the workpieces machined using Selective Laser Melting technology have the microstructure which is a totality of ‘microwelded seams’, which have a significant influence on the behavior of deformation processes in case of machining. The studies have shown that in case of lateral milling of the horizontally grown workpiece, the codirectional microwelded borders prevent any significant deformation of the misalignment which increases the cutting force by up to 10% as compared with milling of the vertically grown workpiece.

  20. Applications of high power lasers. [using reflection holograms for machining and surface treatment

    Science.gov (United States)

    Angus, J. C.

    1979-01-01

    The use of computer generated, reflection holograms in conjunction with high power lasers for precision machining of metals and ceramics was investigated. The Reflection holograms which were developed and made to work at both optical wavelength (He-Ne, 6328 A) and infrared (CO2, 10.6) meet the primary practical requirement of ruggedness and are relatively economical and simple to fabricate. The technology is sufficiently advanced now so that reflection holography could indeed be used as a practical manufacturing device in certain applications requiring low power densities. However, the present holograms are energy inefficient and much of the laser power is lost in the zero order spot and higher diffraction orders. Improvements of laser machining over conventional methods are discussed and addition applications are listed. Possible uses in the electronics industry include drilling holes in printed circuit boards making soldered connections, and resistor trimming.

  1. Robust non-wetting PTFE surfaces by femtosecond laser machining.

    Science.gov (United States)

    Liang, Fang; Lehr, Jorge; Danielczak, Lisa; Leask, Richard; Kietzig, Anne-Marie

    2014-08-08

    Nature shows many examples of surfaces with extraordinary wettability,which can often be associated with particular air-trapping surface patterns. Here,robust non-wetting surfaces have been created by femtosecond laser ablation of polytetrafluoroethylene (PTFE). The laser-created surface structure resembles a forest of entangled fibers, which support structural superhydrophobicity even when the surface chemistry is changed by gold coating. SEM analysis showed that the degree of entanglement of hairs and the depth of the forest pattern correlates positively with accumulated laser fluence and can thus be influenced by altering various laser process parameters. The resulting fibrous surfaces exhibit a tremendous decrease in wettability compared to smooth PTFE surfaces; droplets impacting the virgin or gold coated PTFE forest do not wet the surface but bounce off. Exploratory bioadhesion experiments showed that the surfaces are truly air-trapping and do not support cell adhesion. Therewith, the created surfaces successfully mimic biological surfaces such as insect wings with robust anti-wetting behavior and potential for antiadhesive applications. In addition, the fabrication can be carried out in one process step, and our results clearly show the insensitivity of the resulting non-wetting behavior to variations in the process parameters,both of which make it a strong candidate for industrial applications.

  2. Picosecond laser machined designed patterns with anti-ice effect

    NARCIS (Netherlands)

    Arnaldo del Cerro, Daniel; Römer, G.R.B.E.; Huis in 't Veld, A.J.

    2010-01-01

    Micromachining using ultra short laser pulses (USLP) has evolved over the past years as a versatile tool for introducing functional features in surfaces at a micrometric and even at a sub wavelength scale. Being able to control the surface topography at this level provides a method to change the wet

  3. Robust Non-Wetting PTFE Surfaces by Femtosecond Laser Machining

    Directory of Open Access Journals (Sweden)

    Fang Liang

    2014-08-01

    Full Text Available Nature shows many examples of surfaces with extraordinary wettability, which can often be associated with particular air-trapping surface patterns. Here, robust non-wetting surfaces have been created by femtosecond laser ablation of polytetrafluoroethylene (PTFE. The laser-created surface structure resembles a forest of entangled fibers, which support structural superhydrophobicity even when the surface chemistry is changed by gold coating. SEM analysis showed that the degree of entanglement of hairs and the depth of the forest pattern correlates positively with accumulated laser fluence and can thus be influenced by altering various laser process parameters. The resulting fibrous surfaces exhibit a tremendous decrease in wettability compared to smooth PTFE surfaces; droplets impacting the virgin or gold coated PTFE forest do not wet the surface but bounce off. Exploratory bioadhesion experiments showed that the surfaces are truly air-trapping and do not support cell adhesion. Therewith, the created surfaces successfully mimic biological surfaces such as insect wings with robust anti-wetting behavior and potential for antiadhesive applications. In addition, the fabrication can be carried out in one process step, and our results clearly show the insensitivity of the resulting non-wetting behavior to variations in the process parameters, both of which make it a strong candidate for industrial applications.

  4. 3D Lasers Increase Efficiency, Safety of Moving Machines

    Science.gov (United States)

    2015-01-01

    Canadian company Neptec Design Group Ltd. developed its Laser Camera System, used by shuttles to render 3D maps of their hulls for assessing potential damage. Using NASA funding, the firm incorporated LiDAR technology and created the TriDAR 3D sensor. Its commercial arm, Neptec Technologies Corp., has sold the technology to Orbital Sciences, which uses it to guide its Cygnus spacecraft during rendezvous and dock operations at the International Space Station.

  5. Time dynamics of burst-train filamentation assisted femtosecond laser machining in glasses.

    Science.gov (United States)

    Esser, Dagmar; Rezaei, Saeid; Li, Jianzhao; Herman, Peter R; Gottmann, Jens

    2011-12-05

    Bursts of femtosecond laser pulses with a repetition rate of f = 38.5MHz were created using a purpose-built optical resonator. Single Ti:Sapphire laser pulses, trapped inside a resonator and released into controllable burst profiles by computer generated trigger delays to a fast Pockels cell switch, drove filamentation-assisted laser machining of high aspect ratio holes deep into transparent glasses. The time dynamics of the hole formation and ablation plume physics on 2-ns to 400-ms time scales were examined in time-resolved side-view images recorded with an intensified-CCD camera during the laser machining process. Transient effects of photoluminescence and ablation plume emissions confirm the build-up of heat accumulation effects during the burst train, the formation of laser-generated filaments and plume-shielding effects inside the deeply etched vias. The small time interval between the pulses in the present burst train enabled a more gentle modification in the laser interaction volume that mitigated shock-induced microcracks compared with single pulses.

  6. Inkjet printing as a technique for filling of micro-wells with biocompatible polymers

    DEFF Research Database (Denmark)

    Marizza, Paolo; Keller, Stephan Sylvest; Boisen, Anja

    2013-01-01

    We present an innovative technique to dispense precise amounts of polymer solutions into large arrays of microscopic wells. An inkjet printer (NP 2.1 GeSim, Germany) is used to fill micro-wells with poly (vinyl pyrrolidone) (PVP K10). The micro-wells are fabricated with cavity diameters of 300 μm...

  7. Novel laser machining of optical fibers for long cavities with low birefringence.

    Science.gov (United States)

    Takahashi, Hiroki; Morphew, Jack; Oručević, Fedja; Noguchi, Atsushi; Kassa, Ezra; Keller, Matthias

    2014-12-15

    We present a novel method of machining optical fiber surfaces with a CO₂ laser for use in Fiber-based Fabry-Perot Cavities (FFPCs). Previously FFPCs were prone to large birefringence and limited to relatively short cavity lengths (≤ 200 μm). These characteristics hinder their use in some applications such as cavity quantum electrodynamics with trapped ions. We optimized the laser machining process to produce large, uniform surface structures. This enables the cavities to achieve high finesse even for long cavity lengths. By rotating the fibers around their axis during the laser machining process the asymmetry resulting from the laser's transverse mode profile is eliminated. Consequently we are able to fabricate fiber mirrors with a high degree of rotational symmetry, leading to remarkably low birefringence. Through measurements of the cavity finesse over a range of cavity lengths and the polarization dependence of the cavity linewidth, we confirmed the quality of the produced fiber mirrors for use in low-birefringence FFPCs.

  8. Microwell engineering characterization for mammalian cell culture process development.

    Science.gov (United States)

    Barrett, Timothy A; Wu, Andrew; Zhang, Hu; Levy, M Susana; Lye, Gary J

    2010-02-01

    Experimentation in shaken microplate formats offers a potential platform technology for the rapid evaluation and optimization of cell culture conditions. Provided that cell growth and antibody production kinetics are comparable to those found in currently used shake flask systems then the microwell approach offers the possibility to obtain early process design data more cost effectively and with reduced material requirements. This work describes a detailed engineering characterization of liquid mixing and gas-liquid mass transfer in microwell systems and their impact on suspension cell cultures. For growth of murine hybridoma cells producing IgG1, 24-well plates have been characterized in terms of energy dissipation (P/V) (via Computational Fluid Dynamics, CFD), fluid flow, mixing and oxygen transfer rate as a function of shaking frequency and liquid fill volume. Predicted k(L)a values varied between 1.3 and 29 h(-1); liquid-phase mixing time, quantified using iodine decolorization experiments, varied from 1.7 s to 3.5 h; while the predicted P/V ranged from 5 to 35 W m(-3). CFD simulations of the shear rate predicted hydrodynamic forces will not be detrimental to cells. For hybridoma cultures however, high shaking speeds (>250 rpm) were shown to have a negative impact on cell growth, while a combination of low shaking speed and high well fill volume (120 rpm, 2,000 microL) resulted in oxygen limited conditions. Based on these findings a first engineering comparison of cell culture kinetics in microwell and shake flask formats was made at matched average energy dissipation rates. Cell growth kinetics and antibody titer were found to be similar in 24-well microtiter plates and 250 mL shake flasks. Overall this work has demonstrated that cell culture performed in shaken microwell plates can provide data that is both reproducible and comparable to currently used shake flask systems while offering at least a 30-fold decrease in scale of operation and material

  9. Research on ultrasonic vibration aided femtosecond laser machining process of transparent materials

    Science.gov (United States)

    Dai, Yutang; Liu, Bin; Yin, Guanglin; Li, Tao; Karanja, Joseph M.

    2015-08-01

    A new process of femtosecond laser micromachining with ultrasonic vibration aided is proposed. An ultrasonic aided device has been designed, and the laser micromachining experiments of transparent materials have been carried out. The effects of the ultrasonic vibration with different power on surface quality and the drilling depth have been investigated, and the mechanism of the ultrasonic vibration aided laser machining has been analyzed. After introducing the ultrasonic vibration device, the residue debris on surface of the ablated trench is significantly reduced, and the drilling depth is increased. These results show that, ultrasonic vibration can effectively improve the surface quality of material processing, increase the depth of the drilling hole and promote the processing efficiency of the femtosecond laser.

  10. Effect of different parameters on machining of SiC/SiC composites via pico-second laser

    Energy Technology Data Exchange (ETDEWEB)

    Li, Weinan; Zhang, Ruoheng [State Key Laboratory of Transient Optics and Photonics, Xi’an Institute of Optics and Precision Mechanics, Chinese Academy of Sciences, Xi’an, Shaanxi 10068 (China); Liu, Yongsheng, E-mail: yongshengliu@nwpu.edu.cn [Science and technology on Thermostructure Composite Materials Laboratory, Northwestern Polytechnical University, Xi’an, Shaanxi 710072 (China); Wang, Chunhui; Wang, Jing [Science and technology on Thermostructure Composite Materials Laboratory, Northwestern Polytechnical University, Xi’an, Shaanxi 710072 (China); Yang, Xiaojun [State Key Laboratory of Transient Optics and Photonics, Xi’an Institute of Optics and Precision Mechanics, Chinese Academy of Sciences, Xi’an, Shaanxi 10068 (China); Cheng, Laifei [Science and technology on Thermostructure Composite Materials Laboratory, Northwestern Polytechnical University, Xi’an, Shaanxi 710072 (China)

    2016-02-28

    Graphical abstract: - Highlights: • The highlights of the manuscript include the following two aspects. • First, we found that the different machining modes (helical line scanning and single ring line scanning) and processing power of machining have remarkable effect on the surface morphology of the machined area, such as the shape, depth and the formation of different surface structures. • Secondly, we investigated that the debris consisted of C, Si and O was observed on the machined surface. • Some of the Si–C bonds of the SiC matrix and fibers would be transformed into Si–O bonds after machined, depending on the processing power. - Abstract: Pico-second laser plays an important role in modern machining technology, especially in machining high hardness materials. In this article, pico-second laser was utilized for irradiation on SiC/SiC composites, and effects of different processing parameters including the machining modes and laser power were discussed in detail. The results indicated that the machining modes and laser power had great effect on machining of SiC/SiC composites. Different types of surface morphology and structure were observed under helical line scanning and single ring line scanning, and the analysis of their formulation was discussed in detail. It was believed that the machining modes would be responsible to the different shapes of machining results at the same parameters. The processing power shall also influence the surface morphology and quality of machining results. In micro-hole drilling process, large amount of debris and fragments were observed within the micro-holes, and XPS analysis showed that there existed Si–O bonds and Si–C bonds, indicating that the oxidation during processing was incomplete. Other surface morphology, such as pores and pits were discussed as well.

  11. High-intensity fibre laser design for micro-machining applications

    Science.gov (United States)

    Ortiz-Neria, D. I.; Martinez-Piñón, F.; Hernandez-Escamilla, H.; Alvarez-Chavez, J. A.

    2010-11-01

    This work is focused on the design of a 250W high-intensity continuous-wave fibre optic laser with a 15μm spot size beam and a beam parameter product (BPP) of 1.8 for its use on Laser-assisted Cold Spray process (LCS) in the micro-machining areas. The metal-powder deposition process LCS, is a novel method based on Cold Spray technique (CS) assisted by laser technology. The LCS accelerates metal powders by the use of a high-pressure gas in order to achieve flash welding of particles over substrate. In LCS, the critical velocity of impact is lower with respect with CS while the powder particle is heated before the deposition by a laser beam. Furthermore, LCS does not heat the powder to achieve high temperatures as it happens in plasma processes. This property puts aside cooling problems which normally happen in sintered processes with high oxygen/nitrogen concentration levels. LCS will be used not only in deposition of thin layers. After careful design, proof of concept, experimental data, and prototype development, it should be feasible to perform micro-machining precise work with the use of the highintensity fibre laser presented in this work, and selective deposition of particles, in a similar way to the well-known Direct Metal Laser Sintering process (DMLS). The fibre laser consists on a large-mode area, Yb3+-doped, semi-diffraction limited, 25-m fibre laser cavity, operating in continuous wave regime. The fibre shows an arguably high slope-efficiency with no signs of roll-over. The measured M2 value is 1.8 and doping concentration of 15000ppm. It was made with a slight modification of the traditional MCVD technique. A full optical characterization will be presented.

  12. Delay time dependence of thermal effect of combined pulse laser machining

    Science.gov (United States)

    Yuan, Boshi; Jin, Guangyong; Ma, Yao; Zhang, Wei

    2016-10-01

    The research focused on the effect of delay time in combined pulse laser machining on the material temperature field. Aiming at the parameter optimization of pulse laser machining aluminum alloy, the combined pulse laser model based on heat conduction equation was introduced. And the finite element analysis software, COMSOL Multiphysics, was also utilized in the research. Without considering the phase transition process of aluminum alloy, the results of the numerical simulation was shown in this paper. By the simulation study of aluminum alloy's irradiation with combined pulse, the effect of the change in delay time of combined pulse on the temperature field of the aluminum alloy and simultaneously the quantized results under the specific laser spot conditions were obtained. Based on the results, several conclusions could be reached, the delay time could affect the rule of temperature changing with time. The reasonable delay time controlling would help improving the efficiency. In addition, when the condition of the laser pulse energy density is constant, the optimal delay time depends on pulse sequence.

  13. High-throughput machining using high average power ultrashort pulse lasers and ultrafast polygon scanner

    Science.gov (United States)

    Schille, Joerg; Schneider, Lutz; Streek, André; Kloetzer, Sascha; Loeschner, Udo

    2016-03-01

    In this paper, high-throughput ultrashort pulse laser machining is investigated on various industrial grade metals (Aluminium, Copper, Stainless steel) and Al2O3 ceramic at unprecedented processing speeds. This is achieved by using a high pulse repetition frequency picosecond laser with maximum average output power of 270 W in conjunction with a unique, in-house developed two-axis polygon scanner. Initially, different concepts of polygon scanners are engineered and tested to find out the optimal architecture for ultrafast and precision laser beam scanning. Remarkable 1,000 m/s scan speed is achieved on the substrate, and thanks to the resulting low pulse overlap, thermal accumulation and plasma absorption effects are avoided at up to 20 MHz pulse repetition frequencies. In order to identify optimum processing conditions for efficient high-average power laser machining, the depths of cavities produced under varied parameter settings are analyzed and, from the results obtained, the characteristic removal values are specified. The maximum removal rate is achieved as high as 27.8 mm3/min for Aluminium, 21.4 mm3/min for Copper, 15.3 mm3/min for Stainless steel and 129.1 mm3/min for Al2O3 when full available laser power is irradiated at optimum pulse repetition frequency.

  14. Modular injection mold manufacturing in a selective laser sintering machine

    Science.gov (United States)

    Ikonen, Ilkka T.; Biles, William E.

    1997-12-01

    Reduced time to market places exacting requirements for the speed and quality of the design, manufacture and testing of new plastic parts. Traditionally, the greatest time for getting a new plastic product prototyped and tested is that for the mold fabrication phase. New metal materials for selective laser sintering (SLS) rapid prototyping technology allow direct mold fabrication for prototype plastic parts. Typically these molds are also useable for small scale production runs up to 50,000 parts. Using this technology prototype parts can be manufactured using the same materials and processes as used for the final product allowing testing of the whole manufacturing process for the prototype. This gives a company new opportunities to get a new or modified product to market faster and cheaper than by using traditional mold making processes. In this paper we describe this new technology and discuss how small and mid-size manufacturing companies can benefit from it.

  15. Quality Monitoring for Laser Welding Based on High-Speed Photography and Support Vector Machine

    Directory of Open Access Journals (Sweden)

    Teng Wang

    2017-03-01

    Full Text Available In order to improve the prediction ability of welding quality during high-power disk laser welding, a new approach was proposed and applied in the classification of the dynamic features of metal vapor plume. Six features were extracted through the color image processing method. Three features, including the area of plume, number of spatters, and horizontal coordinate of plume centroid, were selected based on the classification accuracy rates and Pearson product-moment correlation coefficients. A support vector machine model was adopted to classify the welding quality status into two categories, good or poor. The results demonstrated that the support vector machine model established according to the selected features had satisfactory prediction and generalization ability. The classification accuracy rate was higher than 90%, and the model could be applied in the prediction of welding quality during high-power disk laser welding.

  16. Femtosecond laser micro-machined polyimide films for cell scaffold applications.

    Science.gov (United States)

    Antanavičiūtė, Ieva; Šimatonis, Linas; Ulčinas, Orestas; Gadeikytė, Aušra; Abakevičienė, Brigita; Tamulevičius, Sigitas; Mikalayeva, Valeryia; Skeberdis, Vytenis Arvydas; Stankevičius, Edgaras; Tamulevičius, Tomas

    2016-12-11

    Engineering of sophisticated synthetic 3D scaffolds that allow controlling behavior and location of the cells requires advanced micro/nano fabrication techniques. Ultrafast laser micro-machining employing a 1030 nm wavelength Yb:KGW femtosecond laser and a micro-fabrication workstation for micro-machining of commercially available 12.7 and 25.4 µm thickness polyimide (PI) film was applied. Mechanical properties of the fabricated scaffolds, i.e., arrays of differently spaced holes, were examined via custom-built uniaxial micro-tensile testing and finite element method simulations. We demonstrate that experimental micro-tensile testing results could be numerically simulated and explained by 2-material model, assuming that 2-6 µm width rings around the holes possessed up to 5 times higher Young's modulus and yield stress compared with the rest of the laser intacted PI film areas of "dog-bone" shaped specimens. That was attributed to material modification around the micro-machined holes in the vicinity of the position of the focused laser beam track during trepanning drilling. We demonstrate that virgin PI films provide a suitable environment for the mobility, proliferation, and intercellular communication of human bone marrow mesenchymal stem cells and discuss how cell behavior varies on the micro-machined PI films with holes of different diameters (3.1, 8.4, and 16.7 µm) and hole spacing (30, 35, 40, and 45 µm). We conclude that the holes of 3.1 µm diameter were sufficient for metabolic and genetic communication through membranous tunneling tubes between cells residing on the opposite sides of PI film but prevented the trans-migration of cells through the holes. This article is protected by copyright. All rights reserved.

  17. Relevance Vector Machine and Support Vector Machine Classifier Analysis of Scanning Laser Polarimetry Retinal Nerve Fiber Layer Measurements

    Science.gov (United States)

    Bowd, Christopher; Medeiros, Felipe A.; Zhang, Zuohua; Zangwill, Linda M.; Hao, Jiucang; Lee, Te-Won; Sejnowski, Terrence J.; Weinreb, Robert N.; Goldbaum, Michael H.

    2010-01-01

    Purpose To classify healthy and glaucomatous eyes using relevance vector machine (RVM) and support vector machine (SVM) learning classifiers trained on retinal nerve fiber layer (RNFL) thickness measurements obtained by scanning laser polarimetry (SLP). Methods Seventy-two eyes of 72 healthy control subjects (average age = 64.3 ± 8.8 years, visual field mean deviation =−0.71 ± 1.2 dB) and 92 eyes of 92 patients with glaucoma (average age = 66.9 ± 8.9 years, visual field mean deviation =−5.32 ± 4.0 dB) were imaged with SLP with variable corneal compensation (GDx VCC; Laser Diagnostic Technologies, San Diego, CA). RVM and SVM learning classifiers were trained and tested on SLP-determined RNFL thickness measurements from 14 standard parameters and 64 sectors (approximately 5.6° each) obtained in the circumpapillary area under the instrument-defined measurement ellipse (total 78 parameters). Tenfold cross-validation was used to train and test RVM and SVM classifiers on unique subsets of the full 164-eye data set and areas under the receiver operating characteristic (AUROC) curve for the classification of eyes in the test set were generated. AUROC curve results from RVM and SVM were compared to those for 14 SLP software-generated global and regional RNFL thickness parameters. Also reported was the AUROC curve for the GDx VCC software-generated nerve fiber indicator (NFI). Results The AUROC curves for RVM and SVM were 0.90 and 0.91, respectively, and increased to 0.93 and 0.94 when the training sets were optimized with sequential forward and backward selection (resulting in reduced dimensional data sets). AUROC curves for optimized RVM and SVM were significantly larger than those for all individual SLP parameters. The AUROC curve for the NFI was 0.87. Conclusions Results from RVM and SVM trained on SLP RNFL thickness measurements are similar and provide accurate classification of glaucomatous and healthy eyes. RVM may be preferable to SVM, because it provides a

  18. Additive Manufacturing by selective laser melting the realizer desktop machine and its application for the dental industry

    Science.gov (United States)

    Gebhardt, Andreas; Schmidt, Frank-Michael; Hötter, Jan-Steffen; Sokalla, Wolfgang; Sokalla, Patrick

    Additive Manufacturing of metal parts by Selective Laser Melting has become a powerful tool for the direct manufacturing of complex parts mainly for the aerospace and medical industry. With the introduction of its desktop machine, Realizer targeted the dental market. The contribution describes the special features of the machine, discusses details of the process and shows manufacturing results focused on metal dental devices.

  19. Effect of different parameters on machining of SiC/SiC composites via pico-second laser

    Science.gov (United States)

    Li, Weinan; Zhang, Ruoheng; Liu, Yongsheng; Wang, Chunhui; Wang, Jing; Yang, Xiaojun; Cheng, Laifei

    2016-02-01

    Pico-second laser plays an important role in modern machining technology, especially in machining high hardness materials. In this article, pico-second laser was utilized for irradiation on SiC/SiC composites, and effects of different processing parameters including the machining modes and laser power were discussed in detail. The results indicated that the machining modes and laser power had great effect on machining of SiC/SiC composites. Different types of surface morphology and structure were observed under helical line scanning and single ring line scanning, and the analysis of their formulation was discussed in detail. It was believed that the machining modes would be responsible to the different shapes of machining results at the same parameters. The processing power shall also influence the surface morphology and quality of machining results. In micro-hole drilling process, large amount of debris and fragments were observed within the micro-holes, and XPS analysis showed that there existed Si-O bonds and Si-C bonds, indicating that the oxidation during processing was incomplete. Other surface morphology, such as pores and pits were discussed as well.

  20. Experimental investigation of micro-channels produced in aluminum alloy (AA 2024) through laser machining

    Science.gov (United States)

    Ahmed, Naveed; Alahmari, Abdulrahman M.; Darwish, Saied; Khan, Awais Ahmad

    2016-11-01

    Aluminum and its alloys are growingly used in various applications including micro-channel heat exchangers and heat sinks to facilitate heat transfer though micro-fluidic flows. Micro-channels with precise control over geometrical features are very important in order to design micro-fluidic flow dynamics and its characteristics. In this research, Nd:YAG laser beam micro-milling has been utilized to produce micro-channels in aluminum alloy (AA 2024) having cross-sectional size of 400 × 200 µm2. The objective was to control the material removal rate (MRR) of the process in order to get the micro-channels' geometries (width, depth and taperness of sidewalls) close to the designed geometries. In this context, parametric effects of predominant laser parameters on the process performance have been categorically studied. Quadratic mathematical models have further been developed to estimate the MRR and each geometrical aspect of micro-channels over different levels of laser parameters. Additionally, multi-objective optimization has been performed to get an optimized set of laser parameters generating the accurate machining geometries with appropriate material removal per laser scan. Finally, the models and optimization results were validated through confirmatory experimental tests. The results reveal that the précised micro-channel geometries can be obtained through laser beam micro-milling by selecting the appropriate combination of laser parameters (lamp current intensity of 84.48 %, laser pulse frequency of 35.70 kHz and laser scanning speed of 300 mm/s) that can collectively remove a required amount of material thickness per laser scan.

  1. CAD-CAM generated ear cast by means of a laser scanner and rapid prototyping machine.

    Science.gov (United States)

    Ciocca, Leonardo; Scotti, Roberto

    2004-12-01

    Sculpting a wax ear cast for use when making a definitive prosthesis for a patient who has had auricle ablative surgery, is challenging. It requires a skilled anaplastologist along with complex instrumentation able to perform facial laser scans and reproduce anatomic details. The aim of this article is to present a technique to create a cast by laser scanning a stone cast of the existing ear. A 3D laser scanner develops an integrated 3D digital image of the unaffected ear, which is copied and then mirrored. A rapid prototyping machine collects the necessary data to manufacture the definitive resin ear. This procedure is time and cost effective only if the technology is free of charge.

  2. Fast and intuitive programming of adaptive laser cutting of lace enabled by machine vision

    Science.gov (United States)

    Vaamonde, Iago; Souto-López, Álvaro; García-Díaz, Antón

    2015-07-01

    A machine vision system has been developed, validated, and integrated in a commercial laser robot cell. It permits an offline graphical programming of laser cutting of lace. The user interface allows loading CAD designs and aligning them with images of lace pieces. Different thread widths are discriminated to generate proper cutting program templates. During online operation, the system aligns CAD models of pieces and lace images, pre-checks quality of lace cuts and adapts laser parameters to thread widths. For pieces detected with the required quality, the program template is adjusted by transforming the coordinates of every trajectory point. A low-cost lace feeding system was also developed for demonstration of full process automation.

  3. Design and verification of a novel hollow vibrating module for laser machining.

    Science.gov (United States)

    Wang, Zhaozhao; Jang, Seungbong; Kim, EunHee; Jeon, Yongho; Lee, Soo-Hun; Lee, Moon G

    2015-04-01

    If a vibration module is added on laser machining system, the quality of surface finish and aspect ratio on metals can be significantly enhanced. In this study, a single mobility model of vibrating laser along the path of laser beam was put forward. In order to realize the desired unidirectional motion, a resonance type vibration module with optical lens was designed and manufactured. This cylindrical module was composed of curved-beam flexure elements. The cylindrical coordinate system was established to describe the relationship of a curved-beam flexure element's motion and deformation. In addition, the stiffness matrix of the curved-beam element was obtained. Finite element method and dynamical modeling were provided to analyze the resonance frequency and the displacement of the motion. The feasibility of the design was demonstrated with the help of experiments on frequency response. Experimental results show good agreement with theoretical analysis and simulation predictions.

  4. Fabrication quality analysis of a fiber optic refractive index sensor created by CO2 laser machining.

    Science.gov (United States)

    Chen, Chien-Hsing; Yeh, Bo-Kuan; Tang, Jaw-Luen; Wu, Wei-Te

    2013-03-26

    This study investigates the CO2 laser-stripped partial cladding of silica-based optic fibers with a core diameter of 400 μm, which enables them to sense the refractive index of the surrounding environment. However, inappropriate treatments during the machining process can generate a number of defects in the optic fiber sensors. Therefore, the quality of optic fiber sensors fabricated using CO2 laser machining must be analyzed. The results show that analysis of the fiber core size after machining can provide preliminary defect detection, and qualitative analysis of the optical transmission defects can be used to identify imperfections that are difficult to observe through size analysis. To more precisely and quantitatively detect fabrication defects, we included a tensile test and numerical aperture measurements in this study. After a series of quality inspections, we proposed improvements to the existing CO2 laser machining parameters, namely, a vertical scanning pathway, 4 W of power, and a feed rate of 9.45 cm/s. Using these improved parameters, we created optical fiber sensors with a core diameter of approximately 400 μm, no obvious optical transmission defects, a numerical aperture of 0.52 ± 0.019, a 0.886 Weibull modulus, and a 1.186 Weibull-shaped parameter. Finally, we used the optical fiber sensor fabricated using the improved parameters to measure the refractive indices of various solutions. The results show that a refractive-index resolution of 1.8 × 10(-4) RIU (linear fitting R2 = 0.954) was achieved for sucrose solutions with refractive indices ranging between 1.333 and 1.383. We also adopted the particle plasmon resonance sensing scheme using the fabricated optical fibers. The results provided additional information, specifically, a superior sensor resolution of 5.73 × 10(-5) RIU, and greater linearity at R2 = 0.999.

  5. Enhancing structural integrity of adhesive bonds through pulsed laser surface micro-machining

    KAUST Repository

    Diaz, Edwin Hernandez

    2015-06-01

    Enhancing the effective peel resistance of plastically deforming adhesive joints through laser-based surface micro-machining Edwin Hernandez Diaz Inspired by adhesion examples commonly found in nature, we reached out to examine the effect of different kinds of heterogeneous surface properties that may replicate this behavior and the mechanisms at work. In order to do this, we used pulsed laser ablation on copper substrates (CuZn40) aiming to increase adhesion for bonding. A Yb-fiber laser was used for surface preparation of the substrates, which were probed with a Scanning Electron Microscope (SEM) and X-ray Photoelectron Spectroscopy (XPS). Heterogeneous surface properties were devised through the use of simplified laser micromachined patterns which may induce sequential events of crack arrest propagation, thereby having a leveraging effect on dissipation. The me- chanical performance of copper/epoxy joints with homogeneous and heterogeneous laser micromachined interfaces was then analyzed using the T-peel test. Fractured surfaces were analyzed using SEM to resolve the mechanism of failure and adhesive penetration within induced surface asperities from the treatment. Results confirm positive modifications of the surface morphology and chemistry from laser ablation that enable mechanical interlocking and cohesive failure within the adhesive layer. Remarkable improvements of apparent peel energy, bond toughness, and effective peel force were appreciated with respect to sanded substrates as control samples.

  6. Research of the possibility of using an electrical discharge machining metal powder in selective laser melting

    Science.gov (United States)

    Golubeva, A. A.; Sotov, A. V.; Agapovichev, A. V.; Smelov, V. G.; Dmitriev, V. N.

    2017-02-01

    In this paper the research of a Ni-20Cr-10Fe-3Ti (heat-resistant) alloy metal powder conducted for use in a selective laser melting technology. This metal powder is the slime after electric discharge machining. The technology of cleaning and melting the powder discussed in this article. As a control input of the powder, immediately before 3D printing, dimensional analysis, surface morphology and the internal structure of the powder particles after the treatment were examined using optical and electron microscopes. The powder granules are round, oval, of different diameters with non-metallic inclusions. The internal structure of the particles is solid with no apparent defects. The content of the required diameter of the total volume of test powder granules was 15%. X-ray fluorescence analysis of the powder materials carried out. The possibility of powder melting was investigated in the selective laser melting machine ‘SLM 280HL’. A selection of the melting modes based on the physical properties of the Ni-20Cr-10Fe-3Ti alloy, data obtained from similar studies and a mathematical model of the process. Conclusions on the further investigation of the possibility of using electric discharge machining slime were made.

  7. On-machine characterization of moving paper using a photo-emf laser ultrasonics method

    Science.gov (United States)

    Pouet, Bruno F.; Lafond, Emmanuel F.; Pufahl, Brian; Bacher, Gerald D.; Brodeur, Pierre H.; Klein, Marvin B.

    1999-02-01

    Stiffness properties of paper materials can readily be characterized in the laboratory using conventional ultrasonic techniques. For on-line inspection on a paper machine, due to the high translation velocity and the somewhat fragile nature of the moving paper web, contact ultrasonic techniques using piezoelectric transducers are of limited use. To overcome this limitation, non-contact laser- based ultrasonic techniques can be used. Due to the rough surface of the paper, the reflected light is composed of many speckles. For efficient detection, the receiver must be able to process as many speckles as possible. Adaptive receivers using the photorefractive or photo-emf effects are characterized by a large etendue, and thus, are well suited for detection on paper and paperboard. Moreover, the translation velocity of the moving web implies that the detection system must adapt extremely quickly to the changing speckle pattern. In this work, a photo-emf receiver was used to detect Lamb waves excited using a pulsed Nd:YAG laser in moving paper. Experiments were performed using a variable-speed web simulator at speeds much higher than 1 m.s-1. Results corresponding to various translation speeds are shown, demonstrating the feasibility of laser- based ultrasound for on-machine inspection of paper and paperboard during production.

  8. Laser-Machined Ultra-High-Q Microrod Resonators for Nonlinear Optics

    CERN Document Server

    Del'Haye, Pascal; Papp, Scott B

    2013-01-01

    Optical whispering-gallery microresonators are useful tools in microphotonics, and nonlinear optics at very low threshold powers. Here, we present details about the fabrication of ultra-high-Q whispering-gallery-mode resonators made by CO2-laser lathe machining of fused-quartz rods. The resonators can be fabricated in less than one minute and the obtained optical quality factors exceed Q = 10^9. Demonstrated resonator diameters are in the range between 170 {\\mu}m and 8 mm (free spectral ranges between 390 GHz and 8 GHz). Using these microresonators, a variety of optical nonlinearities are observed, including Raman scattering, Brillouin scattering and four-wave mixing.

  9. Prediction of laser cutting heat affected zone by extreme learning machine

    Science.gov (United States)

    Anicic, Obrad; Jović, Srđan; Skrijelj, Hivzo; Nedić, Bogdan

    2017-01-01

    Heat affected zone (HAZ) of the laser cutting process may be developed based on combination of different factors. In this investigation the HAZ forecasting, based on the different laser cutting parameters, was analyzed. The main goal was to predict the HAZ according to three inputs. The purpose of this research was to develop and apply the Extreme Learning Machine (ELM) to predict the HAZ. The ELM results were compared with genetic programming (GP) and artificial neural network (ANN). The reliability of the computational models were accessed based on simulation results and by using several statistical indicators. Based upon simulation results, it was demonstrated that ELM can be utilized effectively in applications of HAZ forecasting.

  10. Development of Experimental Setup of Metal Rapid Prototyping Machine using Selective Laser Sintering Technique

    Science.gov (United States)

    Patil, S. N.; Mulay, A. V.; Ahuja, B. B.

    2016-08-01

    Unlike in the traditional manufacturing processes, additive manufacturing as rapid prototyping, allows designers to produce parts that were previously considered too complex to make economically. The shift is taking place from plastic prototype to fully functional metallic parts by direct deposition of metallic powders as produced parts can be directly used for desired purpose. This work is directed towards the development of experimental setup of metal rapid prototyping machine using selective laser sintering and studies the various parameters, which plays important role in the metal rapid prototyping using SLS technique. The machine structure in mainly divided into three main categories namely, (1) Z-movement of bed and table, (2) X-Y movement arrangement for LASER movements and (3) feeder mechanism. Z-movement of bed is controlled by using lead screw, bevel gear pair and stepper motor, which will maintain the accuracy of layer thickness. X-Y movements are controlled using timing belt and stepper motors for precise movements of LASER source. Feeder mechanism is then developed to control uniformity of layer thickness metal powder. Simultaneously, the study is carried out for selection of material. Various types of metal powders can be used for metal RP as Single metal powder, mixture of two metals powder, and combination of metal and polymer powder. Conclusion leads to use of mixture of two metals powder to minimize the problems such as, balling effect and porosity. Developed System can be validated by conducting various experiments on manufactured part to check mechanical and metallurgical properties. After studying the results of these experiments, various process parameters as LASER properties (as power, speed etc.), and material properties (as grain size and structure etc.) will be optimized. This work is mainly focused on the design and development of cost effective experimental setup of metal rapid prototyping using SLS technique which will gives the feel of

  11. Wear resistance of machine tools' bionic linear rolling guides by laser cladding

    Science.gov (United States)

    Wang, Yiqiang; Liu, Botao; Guo, Zhengcai

    2017-06-01

    In order to improve the rolling wear resistance (RWR) of linear rolling guides (LRG) as well as prolong the life of machine tools, various shape samples with different units spaces ranged from 1 to 5 mm are designed through the observation of animals in the desert and manufactured by laser cladding. Wear resistance tests reproducing closely the real operational condition are conducted by using a homemade linear reciprocating wear test machine, and wear resistance is evaluated by means of weight loss measurement. Results indicate that the samples with bionic units have better RWR than the untreated one, of which the reticulate treated sample with unit space 3 mm present the best RWR. More specifically, among the punctuate treated samples, the mass loss increases with the increase of unit space; among the striate treated samples, the mass loss changes slightly with the increase of unit space, attaining a minimum at the unit space of 4 mm; among the reticulate treated samples, with the increase of unit space, the mass loss initially decreases, but turns to increase after reaching a minimum at the unit space of 3 mm. Additionally, the samples with striate shape perform better wear resistance than the other shape groups on the whole. From the ratio value of laser treated area to contacted area perspective, that the samples with ratio value between 0.15 and 0.3 possess better wear resistance is concluded.

  12. Step-and-Repeat Nanoimprint-, Photo- and Laser Lithography from One Customised CNC Machine.

    Science.gov (United States)

    Greer, Andrew Im; Della-Rosa, Benoit; Khokhar, Ali Z; Gadegaard, Nikolaj

    2016-12-01

    The conversion of a computer numerical control machine into a nanoimprint step-and-repeat tool with additional laser- and photolithography capacity is documented here. All three processes, each demonstrated on a variety of photoresists, are performed successfully and analysed so as to enable the reader to relate their known lithography process(es) to the findings. Using the converted tool, 1 cm(2) of nanopattern may be exposed in 6 s, over 3300 times faster than the electron beam equivalent. Nanoimprint tools are commercially available, but these can cost around 1000 times more than this customised computer numerical control (CNC) machine. The converted equipment facilitates rapid production and large area micro- and nanoscale research on small grants, ultimately enabling faster and more diverse growth in this field of science. In comparison to commercial tools, this converted CNC also boasts capacity to handle larger substrates, temperature control and active force control, up to ten times more curing dose and compactness. Actual devices are fabricated using the machine including an expanded nanotopographic array and microfluidic PDMS Y-channel mixers.

  13. Step-and-Repeat Nanoimprint-, Photo- and Laser Lithography from One Customised CNC Machine

    Science.gov (United States)

    Greer, Andrew IM; Della-Rosa, Benoit; Khokhar, Ali Z.; Gadegaard, Nikolaj

    2016-03-01

    The conversion of a computer numerical control machine into a nanoimprint step-and-repeat tool with additional laser- and photolithography capacity is documented here. All three processes, each demonstrated on a variety of photoresists, are performed successfully and analysed so as to enable the reader to relate their known lithography process(es) to the findings. Using the converted tool, 1 cm2 of nanopattern may be exposed in 6 s, over 3300 times faster than the electron beam equivalent. Nanoimprint tools are commercially available, but these can cost around 1000 times more than this customised computer numerical control (CNC) machine. The converted equipment facilitates rapid production and large area micro- and nanoscale research on small grants, ultimately enabling faster and more diverse growth in this field of science. In comparison to commercial tools, this converted CNC also boasts capacity to handle larger substrates, temperature control and active force control, up to ten times more curing dose and compactness. Actual devices are fabricated using the machine including an expanded nanotopographic array and microfluidic PDMS Y-channel mixers.

  14. Wear Characterization of Cemented Carbides (WC–CoNi Processed by Laser Surface Texturing under Abrasive Machining Conditions

    Directory of Open Access Journals (Sweden)

    Shiqi Fang

    2017-06-01

    Full Text Available Cemented carbides are outstanding engineering materials widely used in quite demanding material removal applications. In this study, laser surface texturing is implemented for enhancing, at the surface level, the intrinsic bulk-like tribological performance of these materials. In this regard, hexagonal pyramids patterned on the cutting surface of a tungsten cemented carbide grade (WC–CoNi have been successfully introduced by means of laser surface texturing. It simulates the surface topography of conventional honing stones for abrasive application. The laser-produced structure has been tested under abrasive machining conditions with full lubrication. Wear of the structure has been characterized and compared, before and after the abrasive machining test, in terms of changes in geometry aspect and surface integrity. It is found that surface roughness of the machined workpiece was improved by the laser-produced structure. Wear characterization shows that laser treatment did not induce any significant damage to the cemented carbide. During the abrasive machining test, the structure exhibited a high wear resistance. Damage features were only discerned at the contacting surface, whereas geometrical shape of pyramids remained unchanged.

  15. Fs-laser micro machining for μ-TLM resistivity test structures in photovoltaic TCO multilayers

    Science.gov (United States)

    Krause, Stephan; Kaufmann, Kai; Lancaster, Kevin; Naumann, Volker; Großer, Stephan; Hagendorf, Christian

    2016-04-01

    In this work we developed a new approach for resistivity measurements based on fs laser micro machining of μ-TLM test structures. This method is applied to highly resistive interfacial and conductive bulk multilayer systems in photovoltaic TCO thin film devices. Resistivity data has been acquired by a new TLM based method at μm-dimensions (μ-TLM, patent pending, DE 102014211352.0). For this approach, isolating trenches are prepared in the µm range with reasonable effort using fs laser processing. The application of ultrashort pulses with a laser wavelength in the IR range (λ = 1.03 μm) allows selective removal of the top SnO2 layer of the TCO multilayer stack by a reduced thermal influence on the layers beneath and in the adjacent region of the laser trenches. Small effective optical penetration and ablation depth was achieved by an ultrafast thermal ablation mechanism via free carrier absorption at the interface of the SnO2/ITO layers. Therefore the risk of laser induced modification of the electric layer properties is negligible. The μ-TLM test structure results in highly accurate and reproducible resistivity data. Applied to SnO2/ITO/glass double layer stacks, the obtained resistivity values for the SnO2 interfacial layer (ρTO = 40.5 kΩμm) and for the indium tin oxide thin film (ρITO = 1.3 Ωμm) agree with reference data from four-point-probing and from literature.

  16. Chaotropic Etching for Fabricating Microwells for Cell Culture

    Science.gov (United States)

    Tamai, Nobuhiro; Moriguchi, Hiroyuki; Takayama, Yuzo; Jimbo, Yasuhiko; Suzuki, Ikuro; Yasuda, Kenji

    Formation of simple neuronal networks in vitro is one of the promising methods to study biological information processing. Agarose microchambers have several advantages to form and maintain simple network structures. Here, in this work, a novel method for fabricating microwells in an agarose-layer is reported. Chaotropic effects of sodium iodide (NaI) is applied for etching agarose films. A conventional glass micropipette filled with NaI solution was aligned and a small amount of NaI was ejected to surface of the film. The agarose was denatured by the soaked NaI. The denatured agarose was washed out by distilled water. The size of the well was determined by the quantity of ejected NaI solution and its diffusion time. Conditions for fabricating wells of 100 to 600 μm diameters were established. Multiple wells up to 100 were formed on a single surface sequentially by programmed movement of the microscope stage. Rat hippocampal neurons were successfully cultured in the wells. Combining this method with microelectrode-array substrates will enable us of recording neuronal activity from simple neuronal networks as well as co-culture systems of heterogeneous tissues.

  17. Modelling and Calibration Technique of Laser Triangulation Sensors for Integration in Robot Arms and Articulated Arm Coordinate Measuring Machines

    OpenAIRE

    Aguilar, Juan J.; Albajez, José A.; Carlos Cajal; David Guillomía; Jorge Santolaria

    2009-01-01

    A technique for intrinsic and extrinsic calibration of a laser triangulation sensor (LTS) integrated in an articulated arm coordinate measuring machine (AACMM) is presented in this paper. After applying a novel approach to the AACMM kinematic parameter identification problem, by means of a single calibration gauge object, a one-step calibration method to obtain both intrinsic―laser plane, CCD sensor and camera geometry―and extrinsic parameters related to the AACMM main frame has been develope...

  18. One-step femtosecond laser welding and internal machining of three glass substrates

    Science.gov (United States)

    Tan, Hua; Duan, Ji'an

    2017-05-01

    In this paper, it demonstrated one-step femtosecond laser welding and internal machining of three fused silica substrates in the optical- and non-optical-contact regimes by focusing 1030-nm laser pulses at the middle of the second substrate. Focusing laser pulses within the second glass in optical-contact and non-optical-contact samples induces permanent internal structural modification, leading to the three glass substrates bonding together simultaneously. The bonding mechanism is based on the internal modification of glass, and this mechanism is different from that of ordinary glass welding at the interface. Welding-spot size is affected by not only the gap distance (ablation effect) and heat transmission, but also by gravity through examining the sizes of the welding spots on the four contact welding surfaces. The maximum bonding strength of the lower interface (56.2 MPa) in the optical-contact regime is more than double that (27.6 MPa) in the non-optical-contact regime.

  19. Integrating a Machine Protection System for High-Current Free Electron Lasers and Energy Recovery Linacs

    Energy Technology Data Exchange (ETDEWEB)

    Trent Allison; James Coleman; Richard Evans; Al Grippo; Kevin Jordan

    2002-09-01

    A fully integrated Machine Protection System (MPS) is critical to efficient commissioning and safe operation of all high-current accelerators. The MPS needs to monitor the status of all devices that could enter the beam path, the beam loss monitors (BLMs), magnet settings, beam dump status, etc. This information is then presented to the electron source controller, which must limit the beam power or shut down the beam completely. The MPS for the energy recovery linac (ERL) at the Jefferson Lab Free Electron Laser [1] generates eight different power limits, or beam modes, which are passed to the drive laser pulse controller (DLPC) (photocathode source controller). These range from no beam to nearly 2 megawatts of electron beam power. Automatic masking is used for the BLMs during low-power modes when one might be using beam viewers. The system also reviews the setup for the two different beamlines, the IR path or the UV path, and will allow or disallow operations based on magnet settings and valve positions. This paper will describe the approach taken for the JLab 10-kW FEL. Additional details can be found on our website http://laser.jlab.org [2].

  20. Direct selective laser sintering of high performance metals: Machine design, process development and process control

    Science.gov (United States)

    Das, Suman

    1998-11-01

    This dissertation describes the development of an advanced manufacturing technology known as Direct Selective Laser Sintering (Direct SLS). Direct SLS is a laser based rapid manufacturing technology that enables production of functional, fully dense, metal and cermet components via the direct, layerwise consolidation of constituent powders. Specifically, this dissertation focuses on a new, hybrid net shape manufacturing technique known as Selective Laser Sintering/Hot Isostatic Pressing (SLS/HIP). The objective of research presented in this dissertation was to establish the fundamental machine technology and processing science to enable direct SLS fabrication of metal components composed of high performance, high temperature metals and alloys. Several processing requirements differentiate direct SLS of metals from SLS of polymers or polymer coated powders. Perhaps the most important distinguishing characteristic is the regime of high temperatures involved in direct SLS of metals. Biasing the temperature of the feedstock powder via radiant preheat prior to and during SLS processing was shown to be beneficial. Preheating the powder significantly influenced the flow and wetting characteristics of the melt. During this work, it was conclusively established that powder cleanliness is of paramount importance for successful layerwise consolidation of metal powders by direct SLS. Sequential trials were conducted to establish optimal bake-out and degas cycles under high vacuum. These cycles agreed well with established practices in the powder metallurgy industry. A study of some of the important transport mechanisms in direct SLS of metals was undertaken to obtain a fundamental understanding of the underlying process physics. This study not only provides an explanation of phenomena observed during SLS processing of a variety of metallic materials but also helps in developing selection schemes for those materials that are most amenable to direct SLS processing. The

  1. Surface-Enhanced Raman Scattering of Bacteria in Microwells Constructed from Silver Nanoparticles

    Directory of Open Access Journals (Sweden)

    Mustafa Çulha

    2012-01-01

    Full Text Available Whole bacterial cell characterization is critically important for fast bacterial identification. Surface-enhanced Raman scattering (SERS is proven to be powerful technique to serve such a goal. In this study, the characterization of whole bacterial cells in the microwells constructed from colloidal silver nanoparticles (AgNPs with “convective-assembly” method is reported. The proper size of the microwells for the model bacteria, Escherichia coli and Staphylococcus cohnii, is determined to be 1.2 μm from their electron microscopy images. A minimum dilution factor of 20 is necessary for the bacterial samples collected from growth media to diminish the bacterial aggregation to place the bacterial cells into the microwells. The constructed microwell structures are tested for their bacterial SERS performance and compared to the SERS spectra obtained from the samples prepared with a simple mixing of bacteria and AgNPs for the same bacteria. The results indicate that microwell structures not only improve the spectral quality but also increase the reproducibility of the SERS spectra.

  2. Optical Manipulation of Single Magnetic Beads in a Microwell Array on a Digital Microfluidic Chip.

    Science.gov (United States)

    Decrop, Deborah; Brans, Toon; Gijsenbergh, Pieter; Lu, Jiadi; Spasic, Dragana; Kokalj, Tadej; Beunis, Filip; Goos, Peter; Puers, Robert; Lammertyn, Jeroen

    2016-09-01

    The detection of single molecules in magnetic microbead microwell array formats revolutionized the development of digital bioassays. However, retrieval of individual magnetic beads from these arrays has not been realized until now despite having great potential for studying captured targets at the individual level. In this paper, optical tweezers were implemented on a digital microfluidic platform for accurate manipulation of single magnetic beads seeded in a microwell array. Successful optical trapping of magnetic beads was found to be dependent on Brownian motion of the beads, suggesting a 99% chance of trapping a vibrating bead. A tailor-made experimental design was used to screen the effect of bead type, ionic buffer strength, surfactant type, and concentration on the Brownian activity of beads in microwells. With the optimal conditions, the manipulation of magnetic beads was demonstrated by their trapping, retrieving, transporting, and repositioning to a desired microwell on the array. The presented platform combines the strengths of digital microfluidics, digital bioassays, and optical tweezers, resulting in a powerful dynamic microwell array system for single molecule and single cell studies.

  3. Rapid biofabrication of tubular tissue constructs by centrifugal casting in a decellularized natural scaffold with laser-machined micropores.

    Science.gov (United States)

    Kasyanov, Vladimir A; Hodde, Jason; Hiles, Michael C; Eisenberg, Carol; Eisenberg, Leonard; De Castro, Luis E F; Ozolanta, Iveta; Murovska, Modra; Draughn, Robert A; Prestwich, Glenn D; Markwald, Roger R; Mironov, Vladimir

    2009-01-01

    Centrifugal casting allows rapid biofabrication of tubular tissue constructs by suspending living cells in an in situ cross-linkable hydrogel. We hypothesize that introduction of laser-machined micropores into a decellularized natural scaffold will facilitate cell seeding by centrifugal casting and increase hydrogel retention, without compromising the biomechanical properties of the scaffold. Micropores with diameters of 50, 100, and 200 mum were machined at different linear densities in decellularized small intestine submucosa (SIS) planar sheets and tubular SIS scaffolds using an argon laser. The ultimate stress and ultimate strain values for SIS sheets with laser-machined micropores with diameter 50 mum and distance between holes as low as 714 mum were not significantly different from unmachined control SIS specimens. Centrifugal casting of GFP-labeled cells suspended in an in situ cross-linkable hyaluronan-based hydrogel resulted in scaffold recellularization with a high density of viable cells inside the laser-machined micropores. Perfusion tests demonstrated the retention of the cells encapsulated within the HA hydrogel in the microholes. Thus, an SIS scaffold with appropriately sized microholes can be loaded with hydrogel encapsulated cells by centrifugal casting to give a mechanically robust construct that retains the cell-seeded hydrogel, permitting rapid biofabrication of tubular tissue construct in a "bioreactor-free" fashion.

  4. Exploring the depth range for three-dimensional laser machining with aberration correction.

    Science.gov (United States)

    Salter, P S; Baum, M; Alexeev, I; Schmidt, M; Booth, M J

    2014-07-28

    The spherical aberration generated when focusing from air into another medium limits the depth at which ultrafast laser machining can be accurately maintained. We investigate how the depth range may be extended using aberration correction via a liquid crystal spatial light modulator (SLM), in both single point and parallel multi-point fabrication in fused silica. At a moderate numerical aperture (NA = 0.5), high fidelity fabrication with a significant level of parallelisation is demonstrated at the working distance of the objective lens, corresponding to a depth in the glass of 2.4 mm. With a higher numerical aperture (NA = 0.75) objective lens, single point fabrication is demonstrated to a depth of 1 mm utilising the full NA, and deeper with reduced NA, while maintaining high repeatability. We present a complementary theoretical model that enables prediction of the effectiveness of SLM based correction for different aberration magnitudes.

  5. High aspect ratio microstructuring of transparent dielectrics using femtosecond laser pulses: method for optimization of the machining throughput

    Science.gov (United States)

    Hendricks, F.; der Au, J. Aus; Matylitsky, V. V.

    2014-10-01

    High average power, high repetition rate femtosecond lasers with μJ pulse energies are increasingly used for material processing applications. The unique advantage of material processing with sub-picosecond lasers is efficient, fast and localized energy deposition, which leads to high ablation efficiency and accuracy in nearly all kinds of solid materials. This work focuses on the machining of high aspect ratio structures in transparent dielectrics, in particular chemically strengthened Xensation™ glass from Schott using multi-pass ablative material removal. For machining of high aspect ratio structures, among others needed for cutting applications, a novel method to determine the best relation between kerf width and number of overscans is presented. The importance of this relation for optimization of the machining throughput will be demonstrated.

  6. Parametric Optimization of Nd:YAG Laser Beam Machining Process Using Artificial Bee Colony Algorithm

    Directory of Open Access Journals (Sweden)

    Rajarshi Mukherjee

    2013-01-01

    Full Text Available Nd:YAG laser beam machining (LBM process has a great potential to manufacture intricate shaped microproducts with its unique characteristics. In practical applications, such as drilling, grooving, cutting, or scribing, the optimal combination of Nd:YAG LBM process parameters needs to be sought out to provide the desired machining performance. Several mathematical techniques, like Taguchi method, desirability function, grey relational analysis, and genetic algorithm, have already been applied for parametric optimization of Nd:YAG LBM processes, but in most of the cases, suboptimal or near optimal solutions have been reached. This paper focuses on the application of artificial bee colony (ABC algorithm to determine the optimal Nd:YAG LBM process parameters while considering both single and multiobjective optimization of the responses. A comparative study with other population-based algorithms, like genetic algorithm, particle swarm optimization, and ant colony optimization algorithm, proves the global applicability and acceptability of ABC algorithm for parametric optimization. In this algorithm, exchange of information amongst the onlooker bees minimizes the search iteration for the global optimal and avoids generation of suboptimal solutions. The results of two sample paired t-tests also demonstrate its superiority over the other optimization algorithms.

  7. Hybrid soft-lithography/laser machined microchips for the parallel generation of droplets.

    Science.gov (United States)

    Muluneh, M; Issadore, D

    2013-12-21

    Microfluidic chips have been developed to generate droplets and microparticles with control over size, shape, and composition not possible using conventional methods. However, it has remained a challenge to scale-up production for practical applications due to the inherently limited throughput of micro-scale devices. To address this problem, we have developed a self-contained microchip that integrates many (N = 512) micro-scale droplet makers. This 3 × 3 cm(2) PDMS microchip consists of a two-dimensional array of 32 × 16 flow-focusing droplet makers, a network of flow channels that connect them, and only two inputs and one output. The key innovation of this technology is the hybrid use of both soft-lithography and direct laser-micromachining. The microscale resolution of soft lithography is used to fabricate flow-focusing droplet makers that can produce small and precisely defined droplets. Deeply engraved (h ≈ 500 μm) laser-machined channels are utilized to supply each of the droplet makers with its oil phase, aqueous phase, and access to an output channel. The engraved channels' low hydrodynamic resistance ensures that each droplet maker is driven with the same flow rates for highly uniform droplet formation. To demonstrate the utility of this approach, water droplets (d ≈ 80 μm) were generated in hexadecane on both 8 × 1 and 32 × 16 geometries.

  8. A numerical study of ultraprecision machining of monocrystalline silicon with laser nano-structured diamond tools by atomistic simulation

    Science.gov (United States)

    Dai, Houfu; Chen, Genyu; Zhou, Cong; Fang, Qihong; Fei, Xinjiang

    2017-01-01

    Three-dimension molecular dynamics (MD) simulations is employed to investigate the ultraprecision machining of single crystal silicon with structured nanoscale diamond tool fabricated by laser. The advantages and disadvantages of diamond machining using structured tools are discussed in comparison with those of using non-structured tools. The von Mises stress distribution, hydrostatic stress distribution, atomic displacement, stress, the radial distribution function, cutting forces, frictional coefficient, subsurface temperature and potential energy during the nanometric machining process are studied. A theoretical analysis model is also established to investigate the subsurface damage mechanism by analyzing the distribution of residual stress during the nanoscale machining process. The results show that a structured nanoscale tool in machining brittle material silicon causes a smaller hydrostatic stress, a less compressive normal stress σxx and σyy , a lower temperature and a smaller cutting force. However, the structured nanoscale tool machining results in smaller chip volume and more beta-silicon phase. Besides, the friction coefficient for tool with V-shape groove is smaller than those for non-structured tools and other structured nanoscale tools. This means that the tool with V-shape groove can reduce the resistance to cutting during the nanoscale machining process. In addition, the results also point out that the potential energy of subsurface atoms and the number of other atoms for pyramid-structured tool are much smaller than those of using non-structured tools and other structured nanoscale tools.

  9. Investigation of amorphous and crystalline Ni alloys response to machining with micro-second and pico-second lasers

    Energy Technology Data Exchange (ETDEWEB)

    Quintana, I., E-mail: iquintana@tekniker.es [CIC marGUNE, Pol. Ibaitarte 5, 20870, Elgoibar, Guipuzcoa (Spain); Dobrev, T. [Manufacturing Engineering Centre, Cardiff University, Cardiff, CF24 3AA (United Kingdom); Aranzabe, A. [Manufacturing Processes Department, Fundacion Tekniker, Av. Otaola 20, 2060, Eibar, Guipuzcoa (Spain); Lalev, G.; Dimov, S. [Manufacturing Engineering Centre, Cardiff University, Cardiff, CF24 3AA (United Kingdom)

    2009-04-15

    The machining response of amorphous and polycrystalline Ni-based alloys (Ni{sub 78}B{sub 14}Si{sub 8}) when subjected to micro-second and pico-second laser processing is investigated in this research. The shape and topography of craters created with single pulses as a function of laser energy together with holes drilled in both materials were studied. Focused ion beam (FIB) imaging was used to analyse the single craters and the through holes in the amorphous and polycrystalline samples. The material microstructure analysis revealed that processing both materials with micro-second and pico-second lasers does not lead to crystallisation and the short-range atomic ordering of metallic glasses can be retained. When processing the amorphous sample the material laser interactions resulted in a significant ejection of molten material from the bulk that was then followed by its partial re-deposition around the craters. Additionally, there were no signs of crack formation that indicate a higher surface integrity after laser machining. A conclusion is made that laser processing both with short- and long-pulses is a promising technique for micromachining metallic glasses because it does not lead to material crystallisation.

  10. Preliminary Comparison of Properties between Ni-electroplated Stainless Steel Parts Fabricated with Laser Additive Manufacturing and Conventional Machining

    Science.gov (United States)

    Mäkinen, Mika; Jauhiainen, Eeva; Matilainen, Ville-Pekka; Riihimäki, Jaakko; Ritvanen, Jussi; Piili, Heidi; Salminen, Antti

    Laser additive manufacturing (LAM) is a fabrication technology, which enables production of complex parts from metallic materials with mechanical properties comparable to those of conventionally machined parts. These LAM parts are manufactured via melting metallic powder layer by layer with laser beam. Aim of this study is to define preliminarily the possibilities of using electroplating to supreme surface properties. Electrodeposited nickel and chromium as well as electroless (autocatalytic) deposited nickel was used to enhance laser additive manufactured and machined parts properties, like corrosion resistance, friction and wearing. All test pieces in this study were manufactured with a modified research AM equipment, equal to commercial EOS M series. The laser system used for tests was IPG 200 W CW fiber laser. The material used in this study for additive manufacturing was commercial stainless steel powder grade named SS316L. This SS316L is not equal to AISI 316L grade, but commercial name of this kind of powder is widely known in additive manufacturing as SS316L. Material used for fabrication of comparison test pieces (i.e. conventionally manufactured) was AISI 316L stainless steel bar. Electroplating was done in matrix cell and electroless was done in plastic sink properties of plated parts were tested within acetic acid salt spray corrosion chamber (AASS, SFS-EN-ISO 9227 standard). Adhesion of coating, friction and wearing properties were tested with Pin-On-Rod machine. Results show that in these preliminary tests, LAM parts and machined parts have certain differences due to manufacturing route and surface conditions. These have an effect on electroplated and electroless parts features on adhesion, corrosion, wearing and friction. However, further and more detailed studies are needed to fully understand these phenomena.

  11. High-throughput machining using a high-average power ultrashort pulse laser and high-speed polygon scanner

    Science.gov (United States)

    Schille, Joerg; Schneider, Lutz; Streek, André; Kloetzer, Sascha; Loeschner, Udo

    2016-09-01

    High-throughput ultrashort pulse laser machining is investigated on various industrial grade metals (aluminum, copper, and stainless steel) and Al2O3 ceramic at unprecedented processing speeds. This is achieved by using a high-average power picosecond laser in conjunction with a unique, in-house developed polygon mirror-based biaxial scanning system. Therefore, different concepts of polygon scanners are engineered and tested to find the best architecture for high-speed and precision laser beam scanning. In order to identify the optimum conditions for efficient processing when using high-average laser powers, the depths of cavities made in the samples by varying the processing parameter settings are analyzed and, from the results obtained, the characteristic removal values are specified. For overlapping pulses of optimum fluence, the removal rate is as high as 27.8 mm3/min for aluminum, 21.4 mm3/min for copper, 15.3 mm3/min for stainless steel, and 129.1 mm3/min for Al2O3, when a laser beam of 187 W average laser powers irradiates. On stainless steel, it is demonstrated that the removal rate increases to 23.3 mm3/min when the laser beam is very fast moving. This is thanks to the low pulse overlap as achieved with 800 m/s beam deflection speed; thus, laser beam shielding can be avoided even when irradiating high-repetitive 20-MHz pulses.

  12. SU-8 photolithography on reactive plasma thin-films: coated microwells for peptide display.

    Science.gov (United States)

    Marchesan, Silvia; Easton, Christopher D; Styan, Katie E; Leech, Patrick; Gengenbach, Thomas R; Forsythe, John S; Hartley, Patrick G

    2013-08-01

    We have developed a technique to create 50μm-deep microwells coated with a reactive and robust thin film, which withstands photolithographic processing, and allows for subsequent chemical functionalisation with biological cues (i.e. peptides). First, plasma polymerisation of 1-bromopropane was used to generate a bromine-functionalised thin film (BrPP) on a substrate of silicon wafer. Second, an epoxy functionalised polymer UV photoresist, SU-8, was deposited and developed to create 50μm-deep patterned microwells that display the BrPP coating at their base. Third, amino acids or peptides were selectively attached to the bottom of the microwells through bromine displacement by an amine or thiol nucleophile. Each surface functionalisation step was monitored by XPS, AFM, and contact angle measurements. These functionalities were then used as linkers to immobilise enzymes (e.g. HRP), which retain activity at the end of the process as shown by a biochemical activity assay. Peptide promoters of cell attachment were also immobilised and their functionality was evaluated using an L929 fibroblast adhesion assay. In conclusion, this work describes an innovative combination of plasma thin film deposition and photolithography to create 50μm-deep functionalised microwells for peptide display in biological applications.

  13. Modelling and Calibration Technique of Laser Triangulation Sensors for Integration in Robot Arms and Articulated Arm Coordinate Measuring Machines

    Directory of Open Access Journals (Sweden)

    Juan J. Aguilar

    2009-09-01

    Full Text Available A technique for intrinsic and extrinsic calibration of a laser triangulation sensor (LTS integrated in an articulated arm coordinate measuring machine (AACMM is presented in this paper. After applying a novel approach to the AACMM kinematic parameter identification problem, by means of a single calibration gauge object, a one-step calibration method to obtain both intrinsic―laser plane, CCD sensor and camera geometry―and extrinsic parameters related to the AACMM main frame has been developed. This allows the integration of LTS and AACMM mathematical models without the need of additional optimization methods after the prior sensor calibration, usually done in a coordinate measuring machine (CMM before the assembly of the sensor in the arm. The experimental tests results for accuracy and repeatability show the suitable performance of this technique, resulting in a reliable, quick and friendly calibration method for the AACMM final user. The presented method is also valid for sensor integration in robot arms and CMMs.

  14. Modelling and calibration technique of laser triangulation sensors for integration in robot arms and articulated arm coordinate measuring machines.

    Science.gov (United States)

    Santolaria, Jorge; Guillomía, David; Cajal, Carlos; Albajez, José A; Aguilar, Juan J

    2009-01-01

    A technique for intrinsic and extrinsic calibration of a laser triangulation sensor (LTS) integrated in an articulated arm coordinate measuring machine (AACMM) is presented in this paper. After applying a novel approach to the AACMM kinematic parameter identification problem, by means of a single calibration gauge object, a one-step calibration method to obtain both intrinsic-laser plane, CCD sensor and camera geometry-and extrinsic parameters related to the AACMM main frame has been developed. This allows the integration of LTS and AACMM mathematical models without the need of additional optimization methods after the prior sensor calibration, usually done in a coordinate measuring machine (CMM) before the assembly of the sensor in the arm. The experimental tests results for accuracy and repeatability show the suitable performance of this technique, resulting in a reliable, quick and friendly calibration method for the AACMM final user. The presented method is also valid for sensor integration in robot arms and CMMs.

  15. Transient, three-dimensional heat transfer model for the laser assisted machining of silicon nitride: 1. Comparison of predictions with measured surface temperature histories

    Energy Technology Data Exchange (ETDEWEB)

    Rozzi, J.C.; Pfefferkorn, F.E.; Shin, Y.C. [Purdue University, (United States). Laser Assisted Materials Processing Laboratory, School of Mechanical Engineering; Incropera, F.P. [University of Notre Dame, (United States). Aerospace and Mechanical Engineering Department

    2000-04-01

    Laser assisted machining (LAM), in which the material is locally heated by an intense laser source prior to material removal, provides an alternative machining process with the potential to yield higher material removal rates, as well as improved control of workpiece properties and geometry, for difficult-to-machine materials such as structural ceramics. To assess the feasibility of the LAM process and to obtain an improved understanding of governing physical phenomena, experiments have been performed to determine the thermal response of a rotating silicon nitride workpiece undergoing heating by a translating CO{sub 2} laser and material removal by a cutting tool. Using a focused laser pyrometer, surface temperature histories were measured to determine the effect of the rotational and translational speeds, the depth of cut, the laser-tool lead distance, and the laser beam diameter and power on thermal conditions. The measurements are in excellent agreement with predictions based on a transient, three-dimensional numerical solution of the heating and material removal processes. The temperature distribution within the unmachined workpiece is most strongly influenced by the laser power and laser-tool lead distance, as well as by the laser/tool translational velocity. A minimum allowable operating temperature in the material removal region corresponds to the YSiAlON glass transition temperature, below which tool fracture may occur. In a companion paper, the numerical model is used to further elucidate thermal conditions associated with laser assisted machining. (author)

  16. Micropatterned culture of HepG2 spheroids using microwell chip with honeycomb-patterned polymer film.

    Science.gov (United States)

    Yamazaki, Hidekazu; Gotou, Shun; Ito, Koju; Kohashi, Souichi; Goto, Yuki; Yoshiura, Yukiko; Sakai, Yusuke; Yabu, Hiroshi; Shimomura, Masatsugu; Nakazawa, Kohji

    2014-10-01

    Microwell chip culture is a promising technique for the generation of homogenous spheroids. We investigated the relationship between the structure of the bottom surface of microwell chip and the properties of HepG2 spheroid. We developed a microwell chip, the bottom surface of which consisted of a honeycomb-patterned polymer film (honeycomb film) that had a regular porous structure (HF chip). The chip comprised 270 circular microwells; each microwell was 600 μm in diameter and 600 μm in depth. At the center of the honeycomb film, an area, 200 μm in diameter, was modified with collagen to facilitate cell adhesion. With the exception of the collagen-coated area, the entire microwell was modified with polyethylene glycol to eliminate cell adhesion. HepG2 cells formed uniform spheroids when cultured in the microwells of HF chip. Furthermore, the cells passed through the porous structure of honeycomb film and formed spheroids at its opposite side. The spheroid growth of HepG2 cells cultured in HF chip was greater than that when the cells were culture in a microwell chip, the bottom surface of which was made of poly-methylmethacrylate (PMMA chip). The albumin secretion activity of HepG2 spheroids in HF chip was equal to that in PMMA chip. These results indicate that the microwell bottom with a porous structure enhances the cell growth and maintains well the spheroid function. Thus, HF chip is a promising platform for spheroid cell culture.

  17. 液压碳石墨密封环激光辅助车削的加工性能研究%Study on machinability for laser-assisted machining of hydraulic carbon-graphite seal rings

    Institute of Scientific and Technical Information of China (English)

    薄纪康; 张海英

    2012-01-01

    为了实现液压碳石墨密封环的高效车削加工,采用激光辅助加工方法,进行了碳石墨密封环材料的激光辅助车削加工研究.考虑到碳石墨密封环材料具有高强度、高硬度等特点,利用激光束对工件进行局部加热,以提高加工效率、减小切削力和刀具磨损.针对碳石墨M104密封环的车削加工过程,进行了常规切削和激光辅助切削的对比实验研究.设计了激光辅助加工的实验流程,并进行了工艺参量的合理选择,得到了较高的切削效率.结果表明,激光辅助切削的主切削力和径向力分别比常规切削下降了23.5%和19.9%;激光辅助切削的切削区温度分布与常规切削相近;刀具磨损和破损的程度较小,能获得较好的表面加工质量.%To perform high efficient turning of hydraulic carbon-graphite seal rings, the laser-assisted machining of the material of carbon-graphite seal ring was conducted using laser pre-heating. The material of carbon-graphite seal rings has the characteristics of high strength and high hardness, and is typical non-metallic difficult-to-machine material. The laser-assisted machining heats the workpiece using laser beam, improving machining efficiency as well as reducing cutting force and tool wear. The turning process of carbon-graphite M104 seal ring was focused on, and the conventional machining was compared with the laser-assisted machining. The experimental process of laser-assisted machining was designed and reasonable process parameters were selected. A high cutting efficiency was obtained. The main cutting force and radial force decreased by 23. 5% and 19. 9% compared with conventional machining. The temperature distribution in the cutting zone of laser-assisted machining is similar to conventional machining. The laser-assisted machining has less tool wear and can get a better surface quality.

  18. Fabrication of micro-pin array with high aspect ratio on stainless steel using nanosecond laser beam machining

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Se Won [School of Mechanical and Aerospace Engineering, Seoul National University, Gwanak 599 Gwanak-ro, Gwanak-Gu, Seoul, 151-744 (Korea, Republic of); Shin, Hong Shik, E-mail: shinhs05@ut.ac.kr [Department of Energy System Engineering, Korea National University of Transportation, Chungju, Chungbuk, 380-702 (Korea, Republic of); Chu, Chong Nam [School of Mechanical and Aerospace Engineering, Seoul National University, Gwanak 599 Gwanak-ro, Gwanak-Gu, Seoul, 151-744 (Korea, Republic of)

    2013-01-01

    Highlights: Black-Right-Pointing-Pointer A high aspect ratio micro-pin array was fabricated by laser beam machining using the piling of a recast layer. Black-Right-Pointing-Pointer The recast layer could be piled due to the chromium oxide with high surface tension and viscosity of chromium oxide. Black-Right-Pointing-Pointer The machining characteristics for a high aspect ratio micro-pin array were investigated according to laser beam parameters. Black-Right-Pointing-Pointer Experiments for attaching force relative to the surface roughness of the subject plane were carried out. Black-Right-Pointing-Pointer The developed micro-pin array was successfully attached to vertical wall. - Abstract: In this paper, a micro-pin array with a high aspect ratio was fabricated on AISI 304 using laser beam ablation for attachment to a vertical wall. In recent times, there has been research in various fields, including robotics and bio-MEMS, regarding attachment to vertical walls, and micro-pin arrays may offer the best solution. For vertical wall attachment, the micro-pin should have a high aspect ratio, long length, and sharp tip. The recast layer could be piled due to the chromium oxide with high surface tension and viscosity of chromium oxide, and it composed the micro-pins with high aspect ratio. X-ray photoelectron spectroscopy (XPS) was used to identify the characteristics of the piled recast layer. The machining characteristics for a high aspect ratio micro-pin array were investigated according to laser beam machining parameters. In addition, experiments for attaching force relative to the surface roughness of the subject plane were carried out.

  19. Tribotechnical and Energy Assessment of Parts of Working Members of Cultivating Machines After Carburizing and Laser Hardening

    Science.gov (United States)

    Pyndak, V. I.; Novikov, A. E.

    2016-07-01

    Results of experimental studies of low-carbon steel 20 and high-carbon steels of types 70 and 65G after carburizing, heat treatment and laser hardening are presented. The variation of the microhardness of the surface layers of the steels and of their wear resistance due to different variants of hardening is determined. Optimum modes of treatment aimed at raising the strength and wear resistance are suggested for the steels used for working members of cultivating machines.

  20. Effect of microwell chip structure on cell microsphere production of various animal cells.

    Science.gov (United States)

    Sakai, Yusuke; Yoshida, Shirou; Yoshiura, Yukiko; Mori, Rhuhei; Tamura, Tomoko; Yahiro, Kanji; Mori, Hideki; Kanemura, Yonehiro; Yamasaki, Mami; Nakazawa, Kohji

    2010-08-01

    The formation of three-dimensional cell microspheres such as spheroids, embryoid bodies, and neurospheres has attracted attention as a useful culture technique. In this study, we investigated a technique for effective cell microsphere production by using specially prepared microchip. The basic chip design was a multimicrowell structure in triangular arrangement within a 100-mm(2) region in the center of a polymethylmethacrylate (PMMA) plate (24x24 mm(2)), the surface of which was modified with polyethylene glycol (PEG) to render it nonadhesive to cells. We also designed six similar chips with microwell diameters of 200, 300, 400, 600, 800, and 1000 microm to investigate the effect of the microwell diameter on the cell microsphere diameter. Rat hepatocytes, HepG2 cells, mouse embryonic stem (ES) cells, and mouse neural progenitor/stem (NPS) cells formed hepatocyte spheroids, HepG2 spheroids, embryoid bodies, and neurospheres, respectively, in the microwells within 5 days of culture. For all the cells, a single microsphere was formed in each microwell under all the chip conditions, and such microsphere configurations remained throughout the culture period. Furthermore, the microsphere diameters of each type of cell were strongly positively correlated with the microwell diameters of the chips, suggesting that microsphere diameter can be factitiously controlled by using different chip conditions. Thus, this chip technique is a promising cellular platform for tissue engineering or regenerative medicine research, pharmacological and toxicological studies, and fundamental studies in cell biology. Copyright 2010 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.

  1. Landslides Identification Using Airborne Laser Scanning Data Derived Topographic Terrain Attributes and Support Vector Machine Classification

    Science.gov (United States)

    Pawłuszek, Kamila; Borkowski, Andrzej

    2016-06-01

    Since the availability of high-resolution Airborne Laser Scanning (ALS) data, substantial progress in geomorphological research, especially in landslide analysis, has been carried out. First and second order derivatives of Digital Terrain Model (DTM) have become a popular and powerful tool in landslide inventory mapping. Nevertheless, an automatic landslide mapping based on sophisticated classifiers including Support Vector Machine (SVM), Artificial Neural Network or Random Forests is often computationally time consuming. The objective of this research is to deeply explore topographic information provided by ALS data and overcome computational time limitation. For this reason, an extended set of topographic features and the Principal Component Analysis (PCA) were used to reduce redundant information. The proposed novel approach was tested on a susceptible area affected by more than 50 landslides located on Rożnów Lake in Carpathian Mountains, Poland. The initial seven PCA components with 90% of the total variability in the original topographic attributes were used for SVM classification. Comparing results with landslide inventory map, the average user's accuracy (UA), producer's accuracy (PA), and overall accuracy (OA) were calculated for two models according to the classification results. Thereby, for the PCA-feature-reduced model UA, PA, and OA were found to be 72%, 76%, and 72%, respectively. Similarly, UA, PA, and OA in the non-reduced original topographic model, was 74%, 77% and 74%, respectively. Using the initial seven PCA components instead of the twenty original topographic attributes does not significantly change identification accuracy but reduce computational time.

  2. Laser-Machined Microcavities for Simultaneous Measurement of High-Temperature and High-Pressure

    Directory of Open Access Journals (Sweden)

    Zengling Ran

    2014-08-01

    Full Text Available Laser-machined microcavities for simultaneous measurement of high-temperature and high-pressure are demonstrated. These two cascaded microcavities are an air cavity and a composite cavity including a section of fiber and an air cavity. They are both placed into a pressure chamber inside a furnace to perform simultaneous pressure and high-temperature tests. The thermal and pressure coefficients of the short air cavity are ~0.0779 nm/°C and ~1.14 nm/MPa, respectively. The thermal and pressure coefficients of the composite cavity are ~32.3 nm/°C and ~24.4 nm/MPa, respectively. The sensor could be used to separate temperature and pressure due to their different thermal and pressure coefficients. The excellent feature of such a sensor head is that it can withstand high temperatures of up to 400 °C and achieve precise measurement of high-pressure under high temperature conditions.

  3. A review on conventional and laser assisted machining of Aluminium based metal matrix composites

    OpenAIRE

    2014-01-01

    Aluminum based Metal Matrix Composites (Al-MMC) have been found in different industrial applications due its excellent properties compared to conventional materials. Machining of these composites is difficult due to the hard particle reinforcements. The wider usage of these composites is limited due high machining cost and excessive tool wear with conventional machining. Because of increasing demands in industries, any improvement of conventional machining process or any other deployment of a...

  4. Time-optimized laser micro machining by using a new high dynamic and high precision galvo scanner

    Science.gov (United States)

    Jaeggi, Beat; Neuenschwander, Beat; Zimmermann, Markus; Zecherle, Markus; Boeckler, Ernst W.

    2016-03-01

    High accuracy, quality and throughput are key factors in laser micro machining. To obtain these goals the ablation process, the machining strategy and the scanning device have to be optimized. The precision is influenced by the accuracy of the galvo scanner and can further be enhanced by synchronizing the movement of the mirrors with the laser pulse train. To maintain a high machining quality i.e. minimum surface roughness, the pulse-to-pulse distance has also to be optimized. Highest ablation efficiency is obtained by choosing the proper laser peak fluence together with highest specific removal rate. The throughput can now be enhanced by simultaneously increasing the average power, the repetition rate as well as the scanning speed to preserve the fluence and the pulse-to-pulse distance. Therefore a high scanning speed is of essential importance. To guarantee the required excellent accuracy even at high scanning speeds a new interferometry based encoder technology was used, that provides a high quality signal for closed-loop control of the galvo scanner position. Low inertia encoder design enables a very dynamic scanner system, which can be driven to very high line speeds by a specially adapted control solution. We will present results with marking speeds up to 25 m/s using a f = 100 mm objective obtained with a new scanning system and scanner tuning maintaining a precision of about 5 μm. Further it will be shown that, especially for short line lengths, the machining time can be minimized by choosing the proper speed which has not to be the maximum one.

  5. Differentiation of mouse iPS cells is dependent on embryoid body size in microwell chip culture.

    Science.gov (United States)

    Miyamoto, Daisuke; Nakazawa, Kohji

    2016-10-01

    A microwell chip possessing microwells of several hundred micrometers is a promising platform for generating embryoid bodies (EBs) of stem cells. Here, we investigated the effects of initial EB size on the growth and differentiation of mouse iPS cells in microwell chip culture. We fabricated a chip that contained 195 microwells in a triangular arrangement at a diameter of 600 μm. To evaluate the effect of EB size, four similar conditions were designed with different seeding cell densities of 100, 500, 1000, and 2000 cells/EB. The cells in each microwell gradually aggregated and then spontaneously formed a single EB within 1 d of culture, and EB size increased with further cell proliferation. EB growth was regulated by the initial EB size, and the growth ability of smaller EBs was higher than that of larger EBs. Furthermore, stem cell differentiation also depended on the initial EB size, and the EBs at more than 500 cells/EB promoted hepatic and cardiac differentiations, but the EBs at 100 cells/EB preferred vascular differentiation. These results indicated that the initial EB size was one of the important factors controlling the proliferation and differentiation of stem cells in the microwell chip culture.

  6. Large-area imaging micro-well detectors for high-energy astrophysics

    CERN Document Server

    Deines-Jones, P; Hunter, S D; Jahoda, K; Owens, S M

    2002-01-01

    Micro-well detectors are pixelized imaging sensors that can be inexpensively fabricated in very large arrays. Owing to their intrinsic gain and operation at room temperature, they can be instrumented at very low power, per unit area, making them valuable for a variety of space-flight applications where wide-angle X-ray imaging or large-area particle tracking is required. For example, micro-well detectors have been chosen as the focal plane imager for Lobster-ISS, a proposed soft X-ray all-sky monitor. We have fabricated detectors which image X-rays with 200 mu m FWHM resolution at 3 keV. In agreement with other groups using similar geometries, we find nominal proportional counter energy resolution (20% at 6 keV in P-10), and stable operation at gas gains up to 30,000.

  7. Porous microwells for geometry-selective, large-scale microparticle arrays

    Science.gov (United States)

    Kim, Jae Jung; Bong, Ki Wan; Reátegui, Eduardo; Irimia, Daniel; Doyle, Patrick S.

    2017-01-01

    Large-scale microparticle arrays (LSMAs) are key for material science and bioengineering applications. However, previous approaches suffer from trade-offs between scalability, precision, specificity and versatility. Here, we present a porous microwell-based approach to create large-scale microparticle arrays with complex motifs. Microparticles are guided to and pushed into microwells by fluid flow through small open pores at the bottom of the porous well arrays. A scaling theory allows for the rational design of LSMAs to sort and array particles on the basis of their size, shape, or modulus. Sequential particle assembly allows for proximal and nested particle arrangements, as well as particle recollection and pattern transfer. We demonstrate the capabilities of the approach by means of three applications: high-throughput single-cell arrays; microenvironment fabrication for neutrophil chemotaxis; and complex, covert tags by the transfer of an upconversion nanocrystal-laden LSMA.

  8. Evaluation of the expansion of umbilical cord blood derived from CD133+ cells on biocompatible microwells

    Directory of Open Access Journals (Sweden)

    Mina Soufizomorrod

    2016-05-01

    Full Text Available Background: Hematopoietic stem cell transplantation (HSCT is a therapeutic approach for treatment of hematological malignancies and incompatibility of Bone marrow. Umbilical cord blood (UCB has known as an alternative for hematopoietic stem/progenitor cells (HPSC in allogeneic transplantation. The low volume of collected samples is the main hindrance in application of HPSC derived from umbilical cord blood. So, ex vivo expansion of HPSCs is the useful approach to overcome this restriction. The goal of using this system is to produce appropriate amount of hematopoietic stem cells, which have the ability of transplantation and long term haematopoiesis. Material & Methods: In current study CD133+ cells were isolated from cord blood (CB. Isolated cells were seeded on microwells. Then expanded cells proliferation rate and ability in colony formation were assessed and finally were compared with 2 Dimensional (2D culture systems. Results: Our findings demonstrated that CD133+ cells derived from UCB which were cultivated on microwells had significantly higher rate of proliferation in compared with routine cell culture systems. Conclusion: In Current study, it was shown that CD133+ cells’ proliferations which were seeded on PDMS microwells coated with collagen significantly increased. We hope that 3 dimensional (3D microenvironment which mimics the 3D structure of bone marrow can solve the problem of using UCB as an alternative source of bone marrow.

  9. Plasma cell treatment device Plasma-on-Chip: Monitoring plasma-generated reactive species in microwells

    Science.gov (United States)

    Oh, Jun-Seok; Kojima, Shinya; Sasaki, Minoru; Hatta, Akimitsu; Kumagai, Shinya

    2017-01-01

    We have developed a plasma cell treatment device called Plasma-on-Chip that enables the real-time monitoring of a single cell culture during plasma treatment. The device consists of three parts: 1) microwells for cell culture, 2) a microplasma device for generating reactive oxygen and nitrogen species (RONS) for use in cell treatment, and 3) through-holes (microchannels) that connect each microwell with the microplasma region for RONS delivery. Here, we analysed the delivery of the RONS to the liquid culture medium stored in the microwells. We developed a simple experimental set-up using a microdevice and applied in situ ultraviolet absorption spectroscopy with high sensitivity for detecting RONS in liquid. The plasma-generated RONS were delivered into the liquid culture medium via the through-holes fabricated into the microdevice. The RONS concentrations were on the order of 10–100 μM depending on the size of the through-holes. In contrast, we found that the amount of dissolved oxygen was almost constant. To investigate the process of RONS generation, we numerically analysed the gas flow in the through-holes. We suggest that the circulating gas flow in the through-holes promotes the interaction between the plasma (ionised gas) and the liquid, resulting in enhanced RONS concentrations. PMID:28176800

  10. Embryo density may affect embryo quality during in vitro culture in a microwell group culture dish.

    Science.gov (United States)

    Lehner, Adam; Kaszas, Zita; Murber, Akos; Rigo, Janos; Urbancsek, Janos; Fancsovits, Peter

    2017-08-01

    Culturing embryos in groups is a common practice in mammalian embryology. Since the introduction of different microwell dishes, it is possible to identify oocytes or embryos individually. As embryo density (embryo-to-volume ratio) may affect the development and viability of the embryos, the purpose of this study was to assess the effect of different embryo densities on embryo quality. Data of 1337 embryos from 228 in vitro fertilization treatment cycles were retrospectively analyzed. Embryos were cultured in a 25 μl microdrop in a microwell group culture dish containing 9 microwells. Three density groups were defined: Group 1 with 2-4 (6.3-12.5 μl/embryo), Group 2 with 5-6 (4.2-5.0 μl/embryo), and Group 3 with 7-9 (2.8-3.6 μl/embryo) embryos. Proportion of good quality embryos was higher in Group 2 on both days (D2: 18.9 vs. 31.5 vs. 24.7%; p Culturing 5-6 embryos together in a culture volume of 25 μl may benefit embryo quality. As low egg number, position, and distance of the embryos may influence embryo quality, results should be interpreted with caution.

  11. 3D high throughput screening and profiling of embryoid bodies in thermoformed microwell plates.

    Science.gov (United States)

    Vrij, E J; Espinoza, S; Heilig, M; Kolew, A; Schneider, M; van Blitterswijk, C A; Truckenmüller, R K; Rivron, N C

    2016-02-21

    3D organoids using stem cells to study development and disease are now widespread. These models are powerful to mimic in vivo situations but are currently associated with high variability and low throughput. For biomedical research, platforms are thus necessary to increase reproducibility and allow high-throughput screens (HTS). Here, we introduce a microwell platform, integrated in standard culture plates, for functional HTS. Using micro-thermoforming, we form round-bottom microwell arrays from optically clear cyclic olefin polymer films, and assemble them with bottom-less 96-well plates. We show that embryonic stem cells aggregate faster and more reproducibly (centricity, circularity) as compared to a state-of-the-art microwell array. We then run a screen of a chemical library to direct differentiation into primitive endoderm (PrE) and, using on-chip high content imaging (HCI), we identify molecules, including regulators of the cAMP pathway, regulating tissue size, morphology and PrE gene activity. We propose that this platform will benefit to the systematic study of organogenesis in vitro.

  12. Measuring laser power as a force: a new paradigm to accurately monitor optical power during laser-based machining operations

    Science.gov (United States)

    Williams, Paul; Simonds, Brian; Sowards, Jeffrey; Hadler, Joshua

    2016-03-01

    In laser manufacturing operations, accurate measurement of laser power is important for product quality, operational repeatability, and process validation. Accurate real-time measurement of high-power lasers, however, is difficult. Typical thermal power meters must absorb all the laser power in order to measure it. This constrains power meters to be large, slow and exclusive (that is, the laser cannot be used for its intended purpose during the measurement). To address these limitations, we have developed a different paradigm in laser power measurement where the power is not measured according to its thermal equivalent but rather by measuring the laser beam's momentum (radiation pressure). Very simply, light reflecting from a mirror imparts a small force perpendicular to the mirror which is proportional to the optical power. By mounting a high-reflectivity mirror on a high-sensitivity force transducer (scale), we are able to measure laser power in the range of tens of watts up to ~ 100 kW. The critical parameters for such a device are mirror reflectivity, angle of incidence, and scale sensitivity and accuracy. We will describe our experimental characterization of a radiation-pressure-based optical power meter. We have tested it for modulated and CW laser powers up to 92 kW in the laboratory and up to 20 kW in an experimental laser welding booth. We will describe present accuracy, temporal response, sources of measurement uncertainty, and hurdles which must be overcome to have an accurate power meter capable of routine operation as a turning mirror within a laser delivery head.

  13. Optical path design for laser cutting machine%激光切割机光路系统设计

    Institute of Scientific and Technical Information of China (English)

    洪超; 钟昇; 周鹏飞; 崔凯

    2013-01-01

    The physical characteristics of optical transmission and influence of transmission environment of optical path on the quality of CNC laser cutting have been analyzed and studied in the text. The design method and key points of optical path system have been put forward. It provides guidance for optical path system design of the laser cutting machine.%对光束传输的物理特性、传输环境对激光切割机光路的影响等进行了分析和研究,提出了光路系统设计的方法和要点.对激光切割机的光路系统设计具有指导意义.

  14. Machining and metrology systems for free-form laser printer mirrors

    Indian Academy of Sciences (India)

    D W Davis; M Walter; M Takahashi; T Masaki

    2003-10-01

    A major challenge in optics is to make optical components like mirrors and lenses smaller and cheaper. This is achieved by designing optical components that have conformal or free-form shapes. A free-form optic is defined as one that is not symmetrical about any axis. These highly demanding requirements are met by single point diamond machining in rigid ultra precision machine tools.

  15. Time-resolved temperature measurements in a rapid compression machine using quantum cascade laser absorption in the intrapulse mode

    KAUST Repository

    Nasir, Ehson Fawad

    2016-07-16

    A temperature sensor based on the intrapulse absorption spectroscopy technique has been developed to measure in situ temperature time-histories in a rapid compression machine (RCM). Two quantum-cascade lasers (QCLs) emitting near 4.55μm and 4.89μm were operated in pulsed mode, causing a frequency "down-chirp" across two ro-vibrational transitions of carbon monoxide. The down-chirp phenomenon resulted in large spectral tuning (δν ∼2.8cm-1) within a single pulse of each laser at a high pulse repetition frequency (100kHz). The wide tuning range allowed the application of the two-line thermometry technique, thus making the sensor quantitative and calibration-free. The sensor was first tested in non-reactive CO-N2 gas mixtures in the RCM and then applied to cases of n-pentane oxidation. Experiments were carried out for end of compression (EOC) pressures and temperatures ranging 9.21-15.32bar and 745-827K, respectively. Measured EOC temperatures agreed with isentropic calculations within 5%. Temperature rise measured during the first-stage ignition of n-pentane is over-predicted by zero-dimensional kinetic simulations. This work presents, for the first time, highly time-resolved temperature measurements in reactive and non-reactive rapid compression machine experiments. © 2016 Elsevier Ltd.

  16. Precise Hole Drilling in PMMA Using 1064 nm Diode Laser CNC Machine

    Directory of Open Access Journals (Sweden)

    Jinan A. Abdulnabi

    2011-01-01

    Full Text Available This paper represents the outcome of efforts that intended to achieve laser hole drilling execution in polymethylmethacrylate (PMMA of 2.5 mm thickness using 1064 nm diode laser of 5 W output power. Different laser beam powers, exposure time, and positions of the laser spot were taken into consideration with respect to the workpiece. The workpieces were tested in the existence of low-pressure assist gas (20–60 mmHg of air. The experimental results were supported by the predicted results of the analytical model.

  17. Precise Hole Drilling in PMMA Using 1064 nm Diode Laser CNC Machine

    OpenAIRE

    Abdulnabi, Jinan A.; Thaier A. Tawfiq; Anwaar A. Al-Dergazly; Ziad A. Taha; Khalil I. Hajim

    2011-01-01

    This paper represents the outcome of efforts that intended to achieve laser hole drilling execution in polymethylmethacrylate (PMMA) of 2.5 mm thickness using 1064 nm diode laser of 5 W output power. Different laser beam powers, exposure time, and positions of the laser spot were taken into consideration with respect to the workpiece. The workpieces were tested in the existence of low-pressure assist gas (20–60 mmHg of air). The experimental results were supported by the predicted results of ...

  18. Characterization of Machine Variability and Progressive Heat Treatment in Selective Laser Melting of Inconel 718

    Science.gov (United States)

    Prater, Tracie; Tilson, Will; Jones, Zack

    2015-01-01

    The absence of an economy of scale in spaceflight hardware makes additive manufacturing an immensely attractive option for propulsion components. As additive manufacturing techniques are increasingly adopted by government and industry to produce propulsion hardware in human-rated systems, significant development efforts are needed to establish these methods as reliable alternatives to conventional subtractive manufacturing. One of the critical challenges facing powder bed fusion techniques in this application is variability between machines used to perform builds. Even with implementation of robust process controls, it is possible for two machines operating at identical parameters with equivalent base materials to produce specimens with slightly different material properties. The machine variability study presented here evaluates 60 specimens of identical geometry built using the same parameters. 30 samples were produced on machine 1 (M1) and the other 30 samples were built on machine 2 (M2). Each of the 30-sample sets were further subdivided into three subsets (with 10 specimens in each subset) to assess the effect of progressive heat treatment on machine variability. The three categories for post-processing were: stress relief, stress relief followed by hot isostatic press (HIP), and stress relief followed by HIP followed by heat treatment per AMS 5664. Each specimen (a round, smooth tensile) was mechanically tested per ASTM E8. Two formal statistical techniques, hypothesis testing for equivalency of means and one-way analysis of variance (ANOVA), were applied to characterize the impact of machine variability and heat treatment on six material properties: tensile stress, yield stress, modulus of elasticity, fracture elongation, and reduction of area. This work represents the type of development effort that is critical as NASA, academia, and the industrial base work collaboratively to establish a path to certification for additively manufactured parts. For future

  19. MODELING OF LASER MACHINING ON POLYMETHYL METHACRYLATE TO FABRICATE MICROFLUIDIC CHIP

    Institute of Scientific and Technical Information of China (English)

    FU Jianzhong; XIANG Hengfu; CHEN Zichen

    2006-01-01

    The use of a CO2 laser system for fabrication of microfluidic chip on polymethyl methacrylate (PMMA) is presented to reduce fabrication cost and time of chip. The grooving process of the laser system and a model for the depth of microchannels are investigated. The relations between the depth of laser-cut channels and the laser beam power, velocity or the number of passes of the beam along the same channel are evaluated. In the experiments, the laser beam power varies from 0 to 50W, the laser beam scanning velocity varies from 0 to 1 000 mm/s and the passes vary in the range of 1to 10 times. Based on the principle of conservation of energy, the influence of the laser beam velocity,the laser power and the number of groove passes are examined. Considering the grooving interval energy loss, a modified mathematical model has been obtained and experimental data show good agreement with the theoretical model. This approach provides a simple way of predicting groove depths. The system provides a cost alternative of the other methods and it is especially useful on research work of microfluidic prototyping due to the short cycle time of production.

  20. Accurate prediction of X-ray pulse properties from a free-electron laser using machine learning

    Science.gov (United States)

    Sanchez-Gonzalez, A.; Micaelli, P.; Olivier, C.; Barillot, T. R.; Ilchen, M.; Lutman, A. A.; Marinelli, A.; Maxwell, T.; Achner, A.; Agåker, M.; Berrah, N.; Bostedt, C.; Bozek, J. D.; Buck, J.; Bucksbaum, P. H.; Montero, S. Carron; Cooper, B.; Cryan, J. P.; Dong, M.; Feifel, R.; Frasinski, L. J.; Fukuzawa, H.; Galler, A.; Hartmann, G.; Hartmann, N.; Helml, W.; Johnson, A. S.; Knie, A.; Lindahl, A. O.; Liu, J.; Motomura, K.; Mucke, M.; O'Grady, C.; Rubensson, J.-E.; Simpson, E. R.; Squibb, R. J.; Såthe, C.; Ueda, K.; Vacher, M.; Walke, D. J.; Zhaunerchyk, V.; Coffee, R. N.; Marangos, J. P.

    2017-06-01

    Free-electron lasers providing ultra-short high-brightness pulses of X-ray radiation have great potential for a wide impact on science, and are a critical element for unravelling the structural dynamics of matter. To fully harness this potential, we must accurately know the X-ray properties: intensity, spectrum and temporal profile. Owing to the inherent fluctuations in free-electron lasers, this mandates a full characterization of the properties for each and every pulse. While diagnostics of these properties exist, they are often invasive and many cannot operate at a high-repetition rate. Here, we present a technique for circumventing this limitation. Employing a machine learning strategy, we can accurately predict X-ray properties for every shot using only parameters that are easily recorded at high-repetition rate, by training a model on a small set of fully diagnosed pulses. This opens the door to fully realizing the promise of next-generation high-repetition rate X-ray lasers.

  1. Frequency domain fluorescence lifetime microwell-plate platform for respirometry measurements

    Science.gov (United States)

    Chatni, M. R.; Yale, G.; Van Ryckeghem, A.; Porterfield, D. M.

    2010-04-01

    Traditionally micro-well plate based platforms used in biology utilize fluorescence intensity based methods to measure processes of biological relevance. However, fluorescence intensity measurements suffer from calibration drift due to a variety of factors. Photobleaching and self-quenching of the fluorescent dyes cause the intensity signal to drop over the lifetime of sensor immobilized inside the well. Variation in turbidity of the sample during the course of the measurement affects the measured fluorescence intensity. In comparison, fluorescence lifetime measurements are not significantly affected by these factors because fluorescence lifetime is a physico-chemical property of the fluorescent dye. Reliable and inexpensive frequency domain fluorescence lifetime instrumentation platforms are possible because the greater tolerance for optical alignment, and because they can be performed using inexpensive light sources such as LEDs. In this paper we report the development of a frequency domain fluorescence lifetime well-plate platform utilizing an oxygen sensitive transition-metal ligand complex fluorophore with a lifetime in the microsecond range. The fluorescence lifetime dye is incorporated in a polymer matrix and immobilized on the base of micro-well of a 60 well micro-well plate. Respiration measurements are performed in both aqueous and non-aqueous environment. Respirometry measurements were recorded from single Daphnia magna egg in hard water. Daphnia is an aquatic organism, important in environmental toxicology as a standard bioassay and early warning indicator for water quality monitoring. Also respirometry measurements were recorded from Tribolium castaneum eggs, which are common pests in the processed flour industry. These eggs were subjected to mitochondrial electron transport chain inhibitor such as potassium cyanide (KCN) and its effects on egg respiration were measured in real-time.

  2. Ultra-short-pulsed laser-machined nanogratings of laser-induced periodic surface structures on thin molybdenum layers

    NARCIS (Netherlands)

    Scorticati, D.; Römer, G.W.; Lange, D.F. de; Huis In 't Veld, B.

    2012-01-01

    Large areas of regular diffraction nanogratings were produced consisting of so-called laser-induced periodic surface structures (LIPSS) on thin molybdenum layers (<400 nm) deposited on a borosilicate glass substrate. The aim was to produce these structures without ablating nor cracking the molybdenu

  3. Micro-machining workstation for a diode pumped Nd:YAG high-brightness laser system

    NARCIS (Netherlands)

    Kleijhorst, R.A.; Offerhaus, H.L.; Bant, P.

    1998-01-01

    A Nd:YAG micro-machining workstation that allows cutting on a scale of a few microns has been developed and operated. The system incorporates a telescope viewing system that allows control during the work and a software interface to translate AutoCad files. Some examples of the performance are given

  4. Micro machining workstation for a diode pumped Nd:YAG high brightness laser system

    NARCIS (Netherlands)

    Kleijhorst, R.A.; Offerhaus, Herman L.; Bant, P.

    1998-01-01

    A Nd:YAG micro-machining workstation that allows cutting on a scale of a few microns has been developed and operated. The system incorporates a telescope viewing system that allows control during the work and a software interface to translate AutoCad files. Some examples of the performance are

  5. Micro machining workstation for a diode pumped Nd:YAG high brightness laser system

    NARCIS (Netherlands)

    Kleijhorst, R.A.; Offerhaus, Herman L.; Bant, P.

    1998-01-01

    A Nd:YAG micro-machining workstation that allows cutting on a scale of a few microns has been developed and operated. The system incorporates a telescope viewing system that allows control during the work and a software interface to translate AutoCad files. Some examples of the performance are given

  6. A Laser-Driven Linear Collider: Sample Machine Parameters and Configuration

    Energy Technology Data Exchange (ETDEWEB)

    Colby, E.R.; England, R.J.; Noble, R.J.; /SLAC

    2011-05-20

    We present a design concept for an e{sup +}e{sup -} linear collider based on laser-driven dielectric accelerator structures, and discuss technical issues that must be addressed to realize such a concept. With a pulse structure that is quasi-CW, dielectric laser accelerators potentially offer reduced beamstrahlung and pair production, reduced event pileup, and much cleaner environment for high energy physics and. For multi-TeV colliders, these advantages become significant.

  7. Testing relativity again, laser, laser, laser, laser

    NARCIS (Netherlands)

    Einstein, A.

    2015-01-01

    laser, laser, laser, laser, laser, laser, laser, laser, laser, laser, laser, laser, laser, laser, laser, laser, laser, laser, laser, laser, laser, laser, laser, laser, laser, laser, laser, laser, laser, laser, laser, laser, laser, laser, laser, laser, laser, laser, laser, laser, laser, laser, laser,

  8. Experimental analysis on semi-finishing machining of Ti6Al4V additively manufactured by direct melting laser sintering

    Science.gov (United States)

    Imbrogno, Stano; Bordin, Alberto; Bruschi, Stefania; Umbrello, Domenico

    2016-10-01

    The Additive Manufacturing (AM) techniques are particularly appealing especially for titanium aerospace and biomedical components because they permit to achieve a strong reduction of the buy-to-fly ratio. However, finishing machining operations are often necessary to reduce the uneven surface roughness and geometrics because of local missing accuracy. This work shows the influence of the cutting parameters, cutting speed and feed rate, on the cutting forces as well as on the thermal field observed in the cutting zone, during a turning operation carried out on bars made of Ti6Al4V obtained by the AM process called Direct Metal Laser Sintering (DMLS). Moreover, the sub-surface microstructure alterations due to the process are also showed and commented.

  9. Optimization and Analysis of Laser Beam Machining Parameters for Al7075-TiB2 In-situ Composite

    Science.gov (United States)

    Manjoth, S.; Keshavamurthy, R.; Pradeep Kumar, G. S.

    2016-09-01

    The paper focuses on laser beam machining (LBM) of In-situ synthesized Al7075-TiB2 metal matrix composite. Optimization and influence of laser machining process parameters on surface roughness, volumetric material removal rate (VMRR) and dimensional accuracy of composites were studied. Al7075-TiB2 metal matrix composite was synthesized by in-situ reaction technique using stir casting process. Taguchi's L9 orthogonal array was used to design experimental trials. Standoff distance (SOD) (0.3 - 0.5mm), Cutting Speed (1000 - 1200 m/hr) and Gas pressure (0.5 - 0.7 bar) were considered as variable input parameters at three different levels, while power and nozzle diameter were maintained constant with air as assisting gas. Optimized process parameters for surface roughness, volumetric material removal rate (VMRR) and dimensional accuracy were calculated by generating the main effects plot for signal noise ratio (S/N ratio) for surface roughness, VMRR and dimensional error using Minitab software (version 16). The Significant of standoff distance (SOD), cutting speed and gas pressure on surface roughness, volumetric material removal rate (VMRR) and dimensional error were calculated using analysis of variance (ANOVA) method. Results indicate that, for surface roughness, cutting speed (56.38%) is most significant parameter followed by standoff distance (41.03%) and gas pressure (2.6%). For volumetric material removal (VMRR), gas pressure (42.32%) is most significant parameter followed by cutting speed (33.60%) and standoff distance (24.06%). For dimensional error, Standoff distance (53.34%) is most significant parameter followed by cutting speed (34.12%) and gas pressure (12.53%). Further, verification experiments were carried out to confirm performance of optimized process parameters.

  10. Direct laser machining-induced topographic pattern promotes up-regulation of myogenic markers in human mesenchymal stem cells.

    Science.gov (United States)

    Li, Huaqiong; Wen, Feng; Wong, Yee Shan; Boey, Freddy Yin Chiang; Subbu, Venkatraman S; Leong, David Tai; Ng, Kee Woei; Ng, Gary Ka Lai; Tan, Lay Poh

    2012-02-01

    The engineering of tissue is preferably done with stem cells, which can be differentiated into the tissue of interest using biochemical or physical cues. While much effort has been focused on using biological factors to regulate stem cell differentiation, recently interest in the contribution of physical factors has increased. In this work, three-dimensional (3-D) microchannels with topographic micropatterns were fabricated by femtosecond laser machining on a biodegradable polymer (poly(L-lactide-co-ε-caprolactone)) substrate. Two substrates with narrow and wide channels respectively were created. Human mesenchymal stem cells (hMSCs) were cultured on the scaffolds for cell proliferation and cellular organization. Gene expression and the immunostaining of myogenic and neurogenic markers were studied. Both scaffolds improved the cell alignment along the channels as compared to the control group. Microfilaments within hMSCs were more significantly aligned and elongated on the narrower microchannels. The gene expression study revealed significant up-regulation of several hallmark markers associated with myogenesis for hMSCs cultured on the scaffold with narrow microchannels, while osteogenic and neurogenic markers were down-regulated or remained similar to the control at day 14. Immunostaining of myogen- and neurogen-specific differentiation markers were used to further confirm the specific differentiation towards a myogenic lineage. This study demonstrates that femtosecond laser machining is a versatile tool for generating controllable 3-D microchannels with topographic features that can be used to induce specific myogenic differentiation of hMSCs in vitro, even in the absence of biological factors.

  11. Novel temperature modeling and compensation method for bias of ring laser gyroscope based on least-squares support vector machine

    Institute of Scientific and Technical Information of China (English)

    Xudong Yu; Yu Wang; Guo Wei; Pengfei Zhang; Xingwu Long

    2011-01-01

    Bias of ring-laser-gyroscope (RLG) changes with temperature in a nonlinear way. This is an important restraining factor for improving the accuracy of RLG. Considering the limitations of least-squares regression and neural network, we propose a new method of temperature compensation of RLG bias-building function regression model using least-squares support vector machine (LS-SVM). Static and dynamic temperature experiments of RLG bias are carried out to validate the effectiveness of the proposed method. Moreover,the traditional least-squares regression method is compared with the LS-SVM-based method. The results show the maximum error of RLG bias drops by almost two orders of magnitude after static temperature compensation, while bias stability of RLG improves by one order of magnitude after dynamic temperature compensation. Thus, the proposed method reduces the influence of temperature variation on the bias of the RLG effectively and improves the accuracy of the gyro scope considerably.%@@ Bias of ring-laser-gyroscope (RLG) changes with temperature in a nonlinear way.This is an important restraining factor for improving the accuracy of RLG.Considering the limitations of least-squares regression and neural network, we propose a new method of temperature compensation of RLG bias-building function regression model using least-squares support vector machine (LS-SVM).Static and dynamic temperature experiments of RLG bias are carried out to validate the effectiveness of the proposed method.Moreover,the traditional least-squares regression method is compared with the LS-SVM-based method.

  12. Effects of 3D microwell culture on initial fate specification in human embryonic stem cells.

    Science.gov (United States)

    Hsiao, Cheston; Tomai, Matthew; Glynn, Jeremy; Palecek, Sean P

    2014-04-01

    Several studies have demonstrated that 3D culture systems influence human embryonic stem cell (hESC) phenotypes and fate choices. However, the effect that these microenvironmental changes have on signaling pathways governing hESC behaviors is not well understood. Here, we have used a 3D microwell array to investigate differences in activation of developmental pathways between 2D and 3D cultures of both undifferentiated hESCs and hESCs undergoing initial differentiation in embryoid bodies (EBs). We observed increased induction into mesoderm and endoderm and differences in expression of genes from multiple signaling pathways that regulate development, including Wnt/β-catenin, TGF-β superfamily, Notch and FGF during EB-mediated differentiation, in 3D microwells as compared with the 2D substrates. In undifferentiated hESCs, we also observed differences in epithelial-mesenchymal transition phenotypes and the TGFβ/BMP pathway between cultures in 3D and 2D. These results illustrate that 3D culture influences multiple pathways that may regulate the differentiation trajectories of hESCs.

  13. Ultrafast laser ablation and machining large-size structures on porcine bone.

    Science.gov (United States)

    An, Ran; Khadar, Ghadeer W; Wilk, Emilia I; Emigh, Brent; Haugen, Harold K; Wohl, Gregory R; Dunlop, Brett; Anvari, Mehran; Hayward, Joseph E; Fang, Qiyin

    2013-07-01

    When using ultrafast laser ablation in some orthopedic applications where precise cutting/drilling is required with minimal damage to collateral tissue, it is challenging to produce large-sized and deep holes using a tightly focused laser beam. The feasibility of producing deep, millimeter-size structures under different ablation strategies is investigated. X-ray computed microtomography was employed to analyze the morphology of these structures. Our results demonstrated the feasibility of producing holes with sizes required in clinical applications using concentric and helical ablation protocols.

  14. Analysis of machining and machine tools

    CERN Document Server

    Liang, Steven Y

    2016-01-01

    This book delivers the fundamental science and mechanics of machining and machine tools by presenting systematic and quantitative knowledge in the form of process mechanics and physics. It gives readers a solid command of machining science and engineering, and familiarizes them with the geometry and functionality requirements of creating parts and components in today’s markets. The authors address traditional machining topics, such as: single and multiple point cutting processes grinding components accuracy and metrology shear stress in cutting cutting temperature and analysis chatter They also address non-traditional machining, such as: electrical discharge machining electrochemical machining laser and electron beam machining A chapter on biomedical machining is also included. This book is appropriate for advanced undergraduate and graduate mechani cal engineering students, manufacturing engineers, and researchers. Each chapter contains examples, exercises and their solutions, and homework problems that re...

  15. Rapid cell-patterning and microfluidic chip fabrication by crack-free CO2 laser ablation on glass

    Science.gov (United States)

    Yen, Meng-Hua; Cheng, Ji-Yen; Wei, Cheng-Wey; Chuang, Yung-Chuan; Young, Tai-Horng

    2006-07-01

    This paper uses a widely available CO2 laser scriber (λ = 10.6 µm) to perform the direct-writing ablation of quartz, borofloat and pyrex substrates for the development of microfluidic chips and cell chips. The surface quality of the ablated microchannels and the presence of debris and distortion are examined by scanning electron microscopy, atomic force microscopy and surface profile measurement techniques. The developed laser ablation system provides a versatile and economic approach for the fabrication of glass microfluidic chips with crack-free structures. In the laser writing process, the desired microfluidic patterns are designed using commercial computer software and are then transferred to the laser scriber to ablate the trenches. This process eliminates the requirement for corrosive chemicals and photomasks, and hence the overall microchip development time is limited to less than 24 h. Additionally, since the laser writing process is not limited by the dimensions of a photomask, the microchannels can be written over a large substrate area. The machining capability and versatility of the laser writing system are demonstrated through its application to the fabrication of a borofloat microfluidic chip and the writing of a series of asymmetric trenches in a microwell array. It is shown that the minimum attainable trench width is 95 µm and that the maximum trench depth is 225 µm. The system provides an economic and powerful means of rapid glass microfluidic chip development. A rapid cell-patterning method based on this method is also demonstrated.

  16. Investigation on interlaminar shear strength properties of disc laser machined consolidated CF-PPS laminates

    Directory of Open Access Journals (Sweden)

    2011-03-01

    Full Text Available In consequence of an increased interest in using endless carbon fibre reinforced thermoplastic composites (TPC, automated and highly productive processing technologies for cutting and trimming steps of consolidated materials are sought. In this paper, the influence on the thermal effect caused by laser cutting with respect to static strength properties of TPC based on a polyphenylene sulfide (PPS matrix is studied. For the cutting experiments, consolidated TPC laminates at varying thicknesses up to s = 3.1 mm and a disc laser emitting at a wavelength of λ = 1030 nm at a maximum output power of PL = 2 kW are used. For the first time, the resulting magnitude of the heat affected zone (HAZ at the cutting edge of the composite material is correlated with interlaminar shear strength tests. The results are compared to specimens prepared by milling and abrasive water jet cutting. Depending on the laminate thickness, the laser treated TPC samples show comparable properties to those of conventionally processed specimens. A reduced load bearing area, as a consequence of damaged fibre-matrix-adhesion due to laser impact, is identified as main factor for the reduction of interlaminar shear strengths for higher laminate thicknesses.

  17. Refractive microlenses produced by excimer laser machining of poly(methyl methacrylate)

    DEFF Research Database (Denmark)

    Jensen, Martin Frøhling; Krühne, Ulrich; H., L.

    2005-01-01

    A method has been developed whereby refractive microlenses can be produced in poly (methyl methacrylate) by excimer laser irradiation at λ = 248 nm. The lenses are formed by a combined photochemical and thermal process. The lenses are formed as depressions in the substrate material (negative focal...

  18. Sensitivity Enhancement of Bead-based Electrochemical Impedance Spectroscopy (BEIS) biosensor by electric field-focusing in microwells.

    Science.gov (United States)

    Shin, Kyeong-Sik; Ji, Jae Hoon; Hwang, Kyo Seon; Jun, Seong Chan; Kang, Ji Yoon

    2016-11-15

    This paper reports a novel electrochemical impedance spectroscopy (EIS) biosensors that uses magnetic beads trapped in a microwell array to improve the sensitivity of conventional bead-based EIS (BEIS) biosensors. Unloading the previously measured beads by removing the magnetic bar enables the BEIS sensor to be used repeatedly by reloading it with new beads. Despite its recyclability, the sensitivity of conventional BEIS biosensors is so low that it has not attracted much attentions from the biosensor industry. We significantly improved the sensitivity of the BEIS system by introducing of a microwell array that contains two electrodes (a working electrode and a counter electrode) to concentrate the electric field on the surfaces of the beads. We confirmed that the performance of the BEIS sensor in a microwell array using an immunoassay of prostate specific antigen (PSA) in PBS buffer and human plasma. The experimental results showed that a low concentration of PSA (a few tens or hundreds of fg/mL) were detectable as a ratio of the changes in the impedance of the PBS buffer or in human plasma. Therefore, our BEIS sensor with a microwell array could be a promising platform for low cost, high-performance biosensors for applications that require high sensitivity and recyclability.

  19. Novel microwell-based spectrophotometric assay for determination of atorvastatin calcium in its pharmaceutical formulations

    Directory of Open Access Journals (Sweden)

    Abdel-Rahman Hamdy M

    2011-10-01

    Full Text Available Abstract The formation of a colored charge-transfer (CT complex between atorvastatin calcium (ATR-Ca as a n-electron donor and 2, 3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ as a π-electron acceptor was investigated, for the first time. The spectral characteristics of the CT complex have been described, and the reaction mechanism has been proved by computational molecular modeling. The reaction was employed in the development of a novel microwell-based spectrophotometric assay for determination of ATR-Ca in its pharmaceutical formulations. The proposed assay was carried out in 96-microwell plates. The absorbance of the colored-CT complex was measured at 460 nm by microwell-plate absorbance reader. The optimum conditions of the reaction and the analytical procedures of the assay were established. Under the optimum conditions, linear relationship with good correlation coefficient (0.9995 was found between the absorbance and the concentration of ATR-Ca in the range of 10-150 μg/well. The limits of detection and quantitation were 5.3 and 15.8 μg/well, respectively. No interference was observed from the additives that are present in the pharmaceutical formulation or from the drugs that are co-formulated with ATR-Ca in its combined formulations. The assay was successfully applied to the analysis of ATR-Ca in its pharmaceutical dosage forms with good accuracy and precision. The assay described herein has great practical value in the routine analysis of ATR-Ca in quality control laboratories, as it has high throughput property, consumes minimum volume of organic solvent thus it offers the reduction in the exposures of the analysts to the toxic effects of organic solvents, and reduction in the analysis cost by 50-fold. Although the proposed assay was validated for ATR-Ca, however, the same methodology could be used for any electron-donating analyte for which a CT reaction can be performed.

  20. Utilization of graphene electrode in transparent microwell arrays for high throughput cell trapping and lysis.

    Science.gov (United States)

    Ameri, S Kabiri; Singh, P K; Sonkusale, S

    2014-11-15

    Here we present a high-throughput, transparent microfluidic device with embedded microwell arrays sandwiched between transparent electrodes made from graphene (at the bottom) and indium tin oxide (at the top) for dielectrophoretic cell trapping and electrical lysis. Graphene suppresses unwanted faradaic reaction effects on the cells and the medium that is typically observed in ITO based electrodes from application of DC field for electrical lysis. This is because graphene is more electrochemically inert than indium tin oxide (ITO) where ITO undergoes reduction-oxidation (redox) reaction in the presence of electrolyte in most standard cell media. This redox process also compromises ITO's electrical properties and optical transparency over multiple use. The presented microfluidic device shows high efficiency for cell trapping and lysis and an electrochemically stable behavior for long operational life.

  1. Scanning compound surfaces with no existing CAD model by using laser probe of a coordinate measuring machine

    Science.gov (United States)

    Che, Chenggang

    1992-09-01

    In recent years, the manufacturing of parts with compound surfaces relies more and more on computer integrated manufacturing (CIM) because of the ever increasing complexity of surface features. For a standard CIM cycle, it starts from a computer aided design (CAD) model which was designed previously be experienced mechanical drafters. The CAD model is then interpreted as numerical controlled (NC) machining codes according to which the part is finally manufactured, this is usually referred to as the normal manufacturing process in Figure 1. However, in many cases, a CAD model of a part is not always readily available to begin the CIM cycle. For instance, in automobile industry, the development of new car models takes a long time from concept to model because of the tedious manual digitization process. Also, in some other cases, the mechanical design of a product may need frequent modification, such as ship hulls, aeroplane fuselages, wings and turbine blades, etc. This was traditionally done by copymilling of a master model. In a computer aided manufacturing (CAM) environment, a mathematical model or representation of a part is required to begin a CIM cycle. The automation of the whole manufacturing system requires a rapid part modeling tool. Fortunately, this becomes possible with the advent of recent development in optical sensing devices and many non-contact sensing techniques. Before a part model is established, surface digitization should first be implemented so that enough measurement points can be fitted later, and this is the most important step of the reverse engineering process as in Figure 1. And also, it is obvious that the efficiency and accuracy of the surface modeling relies heavily on the efficiency and accuracy of the surface digitization. The present paper aims at achieving surface digitization accurately and rapidly with a coordinate measurement machine (CMM) and an inexpensive laser range-finding probe. By making full use of the control system of

  2. Proposal to negotiate a collaboration agreement for the design and prototyping of a machine for laser treatment of metallic vacuum chamber walls for electron cloud mitigation at the High Luminosity LHC

    CERN Document Server

    2016-01-01

    Proposal to negotiate a collaboration agreement for the design and prototyping of a machine for laser treatment of metallic vacuum chamber walls for electron cloud mitigation at the High Luminosity LHC

  3. Laser-Induced Forward Transfer-printing of focused ion beam pre-machined crystalline magneto-optic yttrium iron garnet micro-discs.

    Science.gov (United States)

    Sones, C L; Feinaeugle, M; Sposito, A; Gholipour, B; Eason, R W

    2012-07-02

    We present femtosecond laser-induced forward transfer of focused ion beam pre-machined discs of crystalline magneto-optic yttrium iron garnet (YIG) films. Debris-free circular micro-discs with smooth edges and surface uniformity have been successfully printed. The crystalline nature of the printed micro-discs has not been altered by the LIFT printing process, as was confirmed via micro-Raman measurements.

  4. Highly Stretchable Potentiometric pH Sensor Fabricated via Laser Carbonization and Machining of Carbon-Polyaniline Composite.

    Science.gov (United States)

    Rahimi, Rahim; Ochoa, Manuel; Tamayol, Ali; Khalili, Shahla; Khademhosseini, Ali; Ziaie, Babak

    2017-03-15

    The development of stretchable sensors has recently attracted considerable attention. These sensors have been used in wearable and robotics applications, such as personalized health-monitoring, motion detection, and human-machine interfaces. Herein, we report on a highly stretchable electrochemical pH sensor for wearable point-of-care applications that consists of a pH-sensitive working electrode and a liquid-junction-free reference electrode, in which the stretchable conductive interconnections are fabricated by laser carbonizing and micromachining of a polyimide sheet bonded to an Ecoflex substrate. This method produces highly porous carbonized 2D serpentine traces that are subsequently permeated with polyaniline (PANI) as the conductive filler, binding material, and pH-sensitive membrane. The experimental and simulation results demonstrate that the stretchable serpentine PANI/C-PI interconnections with an optimal trace width of 0.3 mm can withstand elongations of up to 135% and are robust to more than 12 000 stretch-and-release cycles at 20% strain without noticeable change in the resistance. The pH sensor displays a linear sensitivity of -53 mV/pH (r(2) = 0.976) with stable performance in the physiological range of pH 4-10. The sensor shows excellent stability to applied longitudinal and transverse strains up to 100% in different pH buffer solutions with a minimal deviation of less than ±4 mV. The material biocompatibility is confirmed with NIH 3T3 fibroblast cells via PrestoBlue assays.

  5. TEM sample preparation by femtosecond laser machining and ion milling for high-rate TEM straining experiments.

    Science.gov (United States)

    Voisin, Thomas; Grapes, Michael D; Zhang, Yong; Lorenzo, Nicholas; Ligda, Jonathan; Schuster, Brian; Weihs, Timothy P

    2016-12-05

    To model mechanical properties of metals at high strain rates, it is important to visualize and understand their deformation at the nanoscale. Unlike post mortem Transmission Electron Microscopy (TEM), which allows one to analyze defects within samples before or after deformation, in situ TEM is a powerful tool that enables imaging and recording of deformation and the associated defect motion during mechanical loading. Unfortunately, all current in situ TEM mechanical testing techniques are limited to quasi-static strain rates. In this context, we are developing a new test technique that utilizes a rapid straining stage and the Dynamic TEM (DTEM) at the Lawrence Livermore National Laboratory (LLNL). The new straining stage can load samples in tension at strain rates as high as 4×10(3)/s using two piezoelectric actuators operating in bending while the DTEM at LLNL can image in movie mode with a time resolution as short as 70ns. Given the piezoelectric actuators are limited in force, speed, and displacement, we have developed a method for fabricating TEM samples with small cross-sectional areas to increase the applied stresses and short gage lengths to raise the applied strain rates and to limit the areas of deformation. In this paper, we present our effort to fabricate such samples from bulk materials. The new sample preparation procedure combines femtosecond laser machining and ion milling to obtain 300µm wide samples with control of both the size and location of the electron transparent area, as well as the gage cross-section and length.

  6. Study on characteristic parameters influencing laser-induced damage threshold of KH(2)PO(4) crystal surface machined by single point diamond turning.

    Science.gov (United States)

    Chen, Mingjun; Li, Mingquan; Cheng, Jian; Jiang, Wei; Wang, Jian; Xu, Qiao

    2011-12-01

    It has fundamental meaning to find the elements influencing the laser-induced damage threshold (LIDT) of KH(2)PO(4) (KDP) crystal and to provide suitable characterization parameters for these factors in order to improve the LIDT of KDP. Using single-point diamond turning (SPDT) to process the KDP crystal, the machined surface quality has important effects on its LIDT. However, there are still not suitable characteristic parameters of surface quality of KDP to correspond with the LIDT nowadays. In this paper, guided by the Fourier model theory, we study deeply the relationship between the relevant characteristic parameters of surface topography of KDP crystal and the experimental LIDT. Research results indicate that the waviness rather than the roughness is the leading topography element on the KDP surface machined by the SPDT method when the LIDT is considered and the amplitude of micro-waviness has greater influence on the light intensity inside the KDP crystal within the scope of dangerous frequencies between (180 μm)(-1) and (90 μm)(-1); with suitable testing equipment, the characteristic parameters of waviness amplitude, such as the arithmetical mean deviation of three-dimensional profile S(a) or root mean square deviation of three-dimensional contour S(q), are able to be considered as suitable parameters to reflect the optical quality of the machined surface in order to judge approximately the LIDT of the KDP surface and guide the machining course.

  7. Machining of fiber reinforced composites

    Science.gov (United States)

    Komanduri, Ranga; Zhang, Bi; Vissa, Chandra M.

    Factors involved in machining of fiber-reinforced composites are reviewed. Consideration is given to properties of composites reinforced with boron filaments, glass fibers, aramid fibers, carbon fibers, and silicon carbide fibers and to polymer (organic) matrix composites, metal matrix composites, and ceramic matrix composites, as well as to the processes used in conventional machining of boron-titanium composites and of composites reinforced by each of these fibers. Particular attention is given to the methods of nonconventional machining, such as laser machining, water jet cutting, electrical discharge machining, and ultrasonic assisted machining. Also discussed are safety precautions which must be taken during machining of fiber-containing composites.

  8. Physics-based simulation modeling and optimization of microstructural changes induced by machining and selective laser melting processes in titanium and nickel based alloys

    Science.gov (United States)

    Arisoy, Yigit Muzaffer

    Manufacturing processes may significantly affect the quality of resultant surfaces and structural integrity of the metal end products. Controlling manufacturing process induced changes to the product's surface integrity may improve the fatigue life and overall reliability of the end product. The goal of this study is to model the phenomena that result in microstructural alterations and improve the surface integrity of the manufactured parts by utilizing physics-based process simulations and other computational methods. Two different (both conventional and advanced) manufacturing processes; i.e. machining of Titanium and Nickel-based alloys and selective laser melting of Nickel-based powder alloys are studied. 3D Finite Element (FE) process simulations are developed and experimental data that validates these process simulation models are generated to compare against predictions. Computational process modeling and optimization have been performed for machining induced microstructure that includes; i) predicting recrystallization and grain size using FE simulations and the Johnson-Mehl-Avrami-Kolmogorov (JMAK) model, ii) predicting microhardness using non-linear regression models and the Random Forests method, and iii) multi-objective machining optimization for minimizing microstructural changes. Experimental analysis and computational process modeling of selective laser melting have been also conducted including; i) microstructural analysis of grain sizes and growth directions using SEM imaging and machine learning algorithms, ii) analysis of thermal imaging for spattering, heating/cooling rates and meltpool size, iii) predicting thermal field, meltpool size, and growth directions via thermal gradients using 3D FE simulations, iv) predicting localized solidification using the Phase Field method. These computational process models and predictive models, once utilized by industry to optimize process parameters, have the ultimate potential to improve performance of

  9. Reproducible culture and differentiation of mouse embryonic stem cells using an automated microwell platform.

    Science.gov (United States)

    Hussain, Waqar; Moens, Nathalie; Veraitch, Farlan S; Hernandez, Diana; Mason, Chris; Lye, Gary J

    2013-08-15

    The use of embryonic stem cells (ESCs) and their progeny in high throughput drug discovery and regenerative medicine will require production at scale of well characterized cells at an appropriate level of purity. The adoption of automated bioprocessing techniques offers the possibility to overcome the lack of consistency and high failure rates seen with current manual protocols. To build the case for increased use of automation this work addresses the key question: "can an automated system match the quality of a highly skilled and experienced person working manually?" To answer this we first describe an integrated automation platform designed for the 'hands-free' culture and differentiation of ESCs in microwell formats. Next we outline a framework for the systematic investigation and optimization of key bioprocess variables for the rapid establishment of validatable Standard Operating Procedures (SOPs). Finally the experimental comparison between manual and automated bioprocessing is exemplified by expansion of the murine Oct-4-GiP ESC line over eight sequential passages with their subsequent directed differentiation into neural precursors. Our results show that ESCs can be effectively maintained and differentiated in a highly reproducible manner by the automated system described. Statistical analysis of the results for cell growth over single and multiple passages shows up to a 3-fold improvement in the consistency of cell growth kinetics with automated passaging. The quality of the cells produced was evaluated using a panel of biological markers including cell growth rate and viability, nutrient and metabolite profiles, changes in gene expression and immunocytochemistry. Automated processing of the ESCs had no measurable negative effect on either their pluripotency or their ability to differentiate into the three embryonic germ layers. Equally important is that over a 6-month period of culture without antibiotics in the medium, we have not had any cases of

  10. Generation of Multicellular Tumor Spheroids with Microwell-Based Agarose Scaffolds for Drug Testing.

    Directory of Open Access Journals (Sweden)

    Xue Gong

    Full Text Available Three dimensional multicellular aggregate, also referred to as cell spheroid or microtissue, is an indispensable tool for in vitro evaluating antitumor activity and drug efficacy. Compared with classical cellular monolayer, multicellular tumor spheroid (MCTS offers a more rational platform to predict in vivo drug efficacy and toxicity. Nevertheless, traditional processing methods such as plastic dish culture with nonadhesive surfaces are regularly time-consuming, laborious and difficult to provide uniform-sized spheroids, thus causing poor reproducibility of experimental data and impeding high-throughput drug screening. In order to provide a robust and effective platform for in vitro drug evaluation, we present an agarose scaffold prepared with the template containing uniform-sized micro-wells in commercially available cell culture plates. The agarose scaffold allows for good adjustment of MCTS size and large-scale production of MCTS. Transparent agarose scaffold also allows for monitoring of spheroid formation under an optical microscopy. The formation of MCTS from MCF-7 cells was prepared using different-size-well templates and systematically investigated in terms of spheroid growth curve, circularity, and cell viability. The doxorubicin cytotoxicity against MCF-7 spheroid and MCF-7 monolayer cells was compared. The drug penetration behavior, cell cycle distribution, cell apoptosis, and gene expression were also evaluated in MCF-7 spheroid. The findings of this study indicate that, compared with cellular monolayer, MCTS provides a valuable platform for the assessment of therapeutic candidates in an in vivo-mimic microenvironment, and thus has great potential for use in drug discovery and tumor biology research.

  11. Application of concave microwells to pancreatic tumor spheroids enabling anticancer drug evaluation in a clinically relevant drug resistance model.

    Directory of Open Access Journals (Sweden)

    Sang-Eun Yeon

    Full Text Available Intrinsic drug resistance of pancreatic ductal adenocarcinoma (PDAC warrants studies using models that are more clinically relevant for identifying novel resistance mechanisms as well as for drug development. Tumor spheroids (TS mimic in vivo tumor conditions associated with multicellular resistance and represent a promising model for efficient drug screening, however, pancreatic cancer cells often fail to form spheroids using conventional methods such as liquid overlay. This study describes the induction of TS of human pancreatic cancer cells (Panc-1, Aspc-1, Capan-2 in concave polydimethylsiloxane (PDMS microwell plates and evaluation of their usefulness as an anticancer efficacy test model. All three cell lines showed TS formation with varying degree of necrosis inside TS. Among these, Panc-1 spheroid with spherical morphology, a rather rough surface, and unique adhesion structures were successfully produced with no notable necrosis in concave microwell plates. Panc-1 TS contained growth factors or enzymes such as TGF-β1, CTGF, and MT1-MMP, and extracellular matrix proteins such as collagen type I, fibronectin, and laminin. Panc-1 cells grown as TS showed changes in stem cell populations and in expression levels of miRNAs that may play roles in chemoresistance. Visualization of drug penetration and detection of viability indicators, such as Ki-67 and MitoSOX, were optimized for TS for quantitative analysis. Water-soluble tetrazolium (MTS and acid phosphatase (APH assays were also successfully optimized. Overall, we demonstrated that concave PDMS microwell plates are a novel platform for preparation of TS of weakly aggregating cells and that Panc-1 spheroids may represent a novel three-dimensional model for anti-pancreatic cancer drug screening.

  12. Application of concave microwells to pancreatic tumor spheroids enabling anticancer drug evaluation in a clinically relevant drug resistance model.

    Science.gov (United States)

    Yeon, Sang-Eun; No, Da Yoon; Lee, Sang-Hoon; Nam, Suk Woo; Oh, Il-Hoan; Lee, Jaehwi; Kuh, Hyo-Jeong

    2013-01-01

    Intrinsic drug resistance of pancreatic ductal adenocarcinoma (PDAC) warrants studies using models that are more clinically relevant for identifying novel resistance mechanisms as well as for drug development. Tumor spheroids (TS) mimic in vivo tumor conditions associated with multicellular resistance and represent a promising model for efficient drug screening, however, pancreatic cancer cells often fail to form spheroids using conventional methods such as liquid overlay. This study describes the induction of TS of human pancreatic cancer cells (Panc-1, Aspc-1, Capan-2) in concave polydimethylsiloxane (PDMS) microwell plates and evaluation of their usefulness as an anticancer efficacy test model. All three cell lines showed TS formation with varying degree of necrosis inside TS. Among these, Panc-1 spheroid with spherical morphology, a rather rough surface, and unique adhesion structures were successfully produced with no notable necrosis in concave microwell plates. Panc-1 TS contained growth factors or enzymes such as TGF-β1, CTGF, and MT1-MMP, and extracellular matrix proteins such as collagen type I, fibronectin, and laminin. Panc-1 cells grown as TS showed changes in stem cell populations and in expression levels of miRNAs that may play roles in chemoresistance. Visualization of drug penetration and detection of viability indicators, such as Ki-67 and MitoSOX, were optimized for TS for quantitative analysis. Water-soluble tetrazolium (MTS) and acid phosphatase (APH) assays were also successfully optimized. Overall, we demonstrated that concave PDMS microwell plates are a novel platform for preparation of TS of weakly aggregating cells and that Panc-1 spheroids may represent a novel three-dimensional model for anti-pancreatic cancer drug screening.

  13. Development of a novel 96-microwell assay with high throughput for determination of olmesartan medoxomil in its tablets

    Directory of Open Access Journals (Sweden)

    Darwish Ibrahim A

    2012-01-01

    Full Text Available Abstract A novel 96-microwell-based spectrophotometric assay has been developed and validated for determination of olmesartan medoxomil (OLM in tablets. The formation of a colored charge-transfer (CT complex between OLM as a n-electron donor and 2, 5-dichloro-3, 6-dihydroxy-1, 4-benzoquinone (p-chloranilic acid, pCA as a π-electron acceptor was investigated, for the first time, and employed as a basis in the development of the proposed assay. The proposed assay was carried out in 96-microwell plates. The absorbance of the colored-CT complex was measured at 490 nm by microwell-plate absorbance reader. The optimum conditions of the reaction and the analytical procedures of the assay were established. Under the optimum conditions, linear relationship with good correlation coefficient was found between the absorbance and the concentration of OLM in the range of 1-200 μg ml-1. The limits of detection and quantitation were 0.3 and 1 μg ml-1, respectively. No interference was observed from the additives that are present in the pharmaceutical formulation or from hydrochlorothiazide and amlodipine that are co-formulated with OLM in some formulations. The assay was successfully applied to the analysis of OLM in tablets with good accuracy and precision. The assay described herein has great practical value in the routine analysis of OLM in quality control laboratories, as it has high throughput property, consumes minimum volume of organic solvent thus it offers the reduction in the exposures of the analysts to the toxic effects of organic solvents, and reduction in the analysis cost by 50-fold. Although the proposed assay was validated for OLM, however, the same methodology could be used for any electron-donating analyte for which a CT reaction can be performed.

  14. Low cost, patterning of human hNT brain cells on parylene-C with UV & IR laser machining.

    Science.gov (United States)

    Raos, Brad J; Unsworth, C P; Costa, J L; Rohde, C A; Doyle, C S; Delivopoulos, E; Murray, A F; Dickinson, M E; Simpson, M C; Graham, E S; Bunting, A S

    2013-01-01

    This paper describes the use of 800nm femtosecond infrared (IR) and 248nm nanosecond ultraviolet (UV) laser radiation in performing ablative micromachining of parylene-C on SiO2 substrates for the patterning of human hNT astrocytes. Results are presented that support the validity of using IR laser ablative micromachining for patterning human hNT astrocytes cells while UV laser radiation produces photo-oxidation of the parylene-C and destroys cell patterning. The findings demonstrate how IR laser ablative micromachining of parylene-C on SiO2 substrates can offer a low cost, accessible alternative for rapid prototyping, high yield cell patterning.

  15. 激光加热辅助引弧微爆炸加工工程陶瓷的试验研究%Experimental Study on Laser Heating-assisted Micro-detonation of Striking Arc Machining Engineering Ceramics

    Institute of Scientific and Technical Information of China (English)

    田欣利; 李富强; 张保国; 王朋晓; 吴志远

    2012-01-01

    For the purpose of proving feasibility that laser heating-assisted machining technology can improve micro-detonation of striking arc machining quality and increase efficiency of machining ceramics, and exploring the influence law of the machining parameters on the process of machining, the experimental system of laser heating-assisted micro-detonation of striking arc machining is designed and influences of process parameters to the material removal rate and edge chipping are studied. The experiment results show that machining ceramics by laser heating-assisted micro-detonation of striking arc machining can increase the material removal rate and improve the edge chipping. The machining efficiency increases with increment of laser power and decreases with the size growth of light spot. With the increase of distance, it rises in advance and then reduces. The edge chipping decreases with the increase of laser power, decreases before increases with the size growth of light spot or the increment of distance. The results provide evidences for studying machining mechanism and choosing proper process parameters of laser heating-assisted micro-detonation of striking arc.%为验证激光加热辅助技术改善引弧微爆炸加工质量和提高加工效率的可行性,探索加工工艺参数对加工过程的影响规律,设计了激光加热辅助引弧微爆炸加工试验系统,并通过试验研究了工艺参数对材料去除率和崩碎的影响规律。试验结果表明:激光加热辅助引弧微爆炸加工陶瓷可以提高材料去除率,改善崩碎情况;加工效率随激光功率的增加而提高,随光斑尺寸的增大而降低,随距离的增加先提高后降低;崩碎随激光功率的增加而减少,随光斑尺寸的增大先减少后增多,随距离的增加先减少后增多。研究结果为激光加热辅助引弧微爆炸加工机理的研究和工艺参数的优化提供了参考依据。

  16. Application of automatic edge-tracing function in CNC laser cutting machine%自动寻边功能在数控激光切割机上的应用

    Institute of Scientific and Technical Information of China (English)

    周亚丽; 邢振宏; 刘健; 靳兵花

    2013-01-01

    介绍了自动寻边功能在数控激光切割机加工大幅面、中厚板时的应用,阐述了该功能的原理及设计思路.该功能提高了生产效率及设备的自动化程度.%The application of automatic edge-tracing function in the CNC laser cutting machine for big-size and medium &thick plate has been introduced in the text. It improves the productivity and the automation degree of the CNC laser cutting machine.

  17. Innovative design for a cutting head rotary mechanism of 3D laser cutting machine%一种三维激光切割机激光头旋转机构的创新设计

    Institute of Scientific and Technical Information of China (English)

    龚立新; 周鹏飞; 胡金龙; 孙健

    2013-01-01

    The exiting cutting head rotary mechanism of 3D laser cutting machine has been illustrated and compared.A rotary mechanism based on composite drive technology has been designed,which provides reference for the R&D of the 3D & 5-axis laser cutting machine.%对现有三维激光切割机的激光头旋转机构进行了介绍和比较,设计了一种基于复合驱动技术的激光头旋转机构,可为三维五轴激光切割机的研发提供参考.

  18. A study of machine learning regression methods for major elemental analysis of rocks using laser-induced breakdown spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Boucher, Thomas F., E-mail: boucher@cs.umass.edu [School of Computer Science, University of Massachusetts Amherst, 140 Governor' s Drive, Amherst, MA 01003, United States. (United States); Ozanne, Marie V. [Department of Astronomy, Mount Holyoke College, South Hadley, MA 01075 (United States); Carmosino, Marco L. [School of Computer Science, University of Massachusetts Amherst, 140 Governor' s Drive, Amherst, MA 01003, United States. (United States); Dyar, M. Darby [Department of Astronomy, Mount Holyoke College, South Hadley, MA 01075 (United States); Mahadevan, Sridhar [School of Computer Science, University of Massachusetts Amherst, 140 Governor' s Drive, Amherst, MA 01003, United States. (United States); Breves, Elly A.; Lepore, Kate H. [Department of Astronomy, Mount Holyoke College, South Hadley, MA 01075 (United States); Clegg, Samuel M. [Los Alamos National Laboratory, P.O. Box 1663, MS J565, Los Alamos, NM 87545 (United States)

    2015-05-01

    The ChemCam instrument on the Mars Curiosity rover is generating thousands of LIBS spectra and bringing interest in this technique to public attention. The key to interpreting Mars or any other types of LIBS data are calibrations that relate laboratory standards to unknowns examined in other settings and enable predictions of chemical composition. Here, LIBS spectral data are analyzed using linear regression methods including partial least squares (PLS-1 and PLS-2), principal component regression (PCR), least absolute shrinkage and selection operator (lasso), elastic net, and linear support vector regression (SVR-Lin). These were compared against results from nonlinear regression methods including kernel principal component regression (K-PCR), polynomial kernel support vector regression (SVR-Py) and k-nearest neighbor (kNN) regression to discern the most effective models for interpreting chemical abundances from LIBS spectra of geological samples. The results were evaluated for 100 samples analyzed with 50 laser pulses at each of five locations averaged together. Wilcoxon signed-rank tests were employed to evaluate the statistical significance of differences among the nine models using their predicted residual sum of squares (PRESS) to make comparisons. For MgO, SiO{sub 2}, Fe{sub 2}O{sub 3}, CaO, and MnO, the sparse models outperform all the others except for linear SVR, while for Na{sub 2}O, K{sub 2}O, TiO{sub 2}, and P{sub 2}O{sub 5}, the sparse methods produce inferior results, likely because their emission lines in this energy range have lower transition probabilities. The strong performance of the sparse methods in this study suggests that use of dimensionality-reduction techniques as a preprocessing step may improve the performance of the linear models. Nonlinear methods tend to overfit the data and predict less accurately, while the linear methods proved to be more generalizable with better predictive performance. These results are attributed to the high

  19. Surface texturing of Si3N4–SiC ceramic tool components by pulsed laser machining

    CSIR Research Space (South Africa)

    Tshabalala, LC

    2016-03-01

    Full Text Available Traditional abrasive techniques such as grinding and lapping have long been used in the surface conditioning of engineering materials. However, in the processing of hard and brittle materials like silicon nitride (Si(sub3)N(sub4)), machining...

  20. Advanced Analysis of Nontraditional Machining

    CERN Document Server

    Tsai, Hung-Yin

    2013-01-01

    Nontraditional machining utilizes thermal, chemical, electrical, mechanical and optical sources of energy to form and cut materials. Advanced Analysis of Nontraditional Machining explains in-depth how each of these advanced machining processes work, their machining system components, and process variables and industrial applications, thereby offering advanced knowledge and scientific insight. This book also documents the latest and frequently cited research results of a few key nonconventional machining processes for the most concerned topics in industrial applications, such as laser machining, electrical discharge machining, electropolishing of die and mold, and wafer processing for integrated circuit manufacturing. This book also: Fills the gap of the advanced knowledge of nonconventional machining between industry and research Documents latest and frequently cited research of key nonconventional machining processes for the most sought after topics in industrial applications Demonstrates advanced multidisci...

  1. When Machines Design Machines!

    DEFF Research Database (Denmark)

    2011-01-01

    Until recently we were the sole designers, alone in the driving seat making all the decisions. But, we have created a world of complexity way beyond human ability to understand, control, and govern. Machines now do more trades than humans on stock markets, they control our power, water, gas...... and food supplies, manage our elevators, microclimates, automobiles and transport systems, and manufacture almost everything. It should come as no surprise that machines are now designing machines. The chips that power our computers and mobile phones, the robots and commercial processing plants on which we...... depend, all are now largely designed by machines. So what of us - will be totally usurped, or are we looking at a new symbiosis with human and artificial intelligences combined to realise the best outcomes possible. In most respects we have no choice! Human abilities alone cannot solve any of the major...

  2. Utilizing the transparency of semiconductors via "backside" machining with a nanosecond 2 μm Tm:fiber laser

    Science.gov (United States)

    Gehlich, Nils; Bonhoff, Tobias; Sisken, Laura; Ramme, Mark; Gaida, Christian; Gebhardt, Martin; Mingareev, Ilya; Shah, Lawrence; Richardson, Martin C.

    2014-03-01

    Semiconductors such as Si and GaAs are transparent to infrared laser radiation with wavelengths >1.2 μm. Focusing laser light at the back surface of a semiconductor wafer enables a novel processing regime that utilizes this transparency. However, in previous experiments with ultrashort laser pulses we have found that nonlinear absorption makes it impossible to achieve sufficient optical intensity to induce material modification far below the front surface. Using a recently developed Tm:fiber laser system producing pulses as short as 7 ns with peak powers exceeding 100 kW, we have demonstrated it is possible to ablate the "backside" surface of 500-600 μm thick Si and GaAs wafers. We studied laser-induced morphology changes at front and back surfaces of wafers and obtained modification thresholds for multipulse irradiation and surface processing in trenches. A significantly higher back surface modification threshold in Si compared to front surface is possibly attributed to nonlinear absorption and light propagation effects. This unique processing regime has the potential to enable novel applications such as semiconductor welding for microelectronics, photovoltaic, and consumer electronics.

  3. Image-guided smart laser system for precision implantation of cells in cartilage

    Science.gov (United States)

    Katta, Nitesh; Rector, John A.; Gardner, Michael R.; McElroy, Austin B.; Choy, Kevin C.; Crosby, Cody; Zoldan, Janet; Milner, Thomas E.

    2017-03-01

    State-of-the-art treatment for joint diseases like osteoarthritis focus on articular cartilage repair/regeneration by stem cell implantation therapy. However, the technique is limited by a lack of precision in the physician's imaging and cell deposition toolkit. We describe a novel combination of high-resolution, rapid scan-rate optical coherence tomography (OCT) alongside a short-pulsed nanosecond thulium (Tm) laser for precise cell seeding in cartilage. The superior beam quality of thulium lasers and wavelength of operation 1940 nm offers high volumetric tissue removal rates and minimizes the residual thermal footprint. OCT imaging enables targeted micro-well placement, precise cell deposition, and feature contrast. A bench-top system is constructed using a 15 W, 1940 nm, nanosecond-pulsed Tm fiber laser (500 μJ pulse energy, 100 ns pulse duration, 30kHz repetition rate) for removing tissue, and a swept source laser (1310 ± 70 nm, 100 kHz sweep rate) for OCT imaging, forming a combined Tm/OCT system - a "smart laser knife". OCT assists the smart laser knife user in characterizing cartilage to inform micro-well placement. The Tm laser creates micro-wells (2.35 mm diameter length, 1.5 mm width, 300 μm deep) and micro-incisions (1 mm wide, 200 μm deep) while OCT image-guidance assists and demonstrates this precision cutting and cell deposition with real-time feedback. To test micro-well creation and cell deposition protocol, gelatin phantoms are constructed mimicking cartilage optical properties and physiological structure. Cell viability is then assessed to illustrate the efficacy of the hydrogel deposition. Automated OCT feedback is demonstrated for cutting procedures to avoid important surface/subsurface structures. This bench-top smart laser knife system described here offers a new image-guided approach to precise stem cell seeding that can enhance the efficacy of articular cartilage repair.

  4. Surface texturing of Si3N4–SiC ceramic tool components by pulsed laser machining

    CSIR Research Space (South Africa)

    Tshabalala, LC

    2016-03-01

    Full Text Available is often accompanied by numerous shortcomings which either lead to poor surface quality or residual surface damage of the workpiece. In this sense, this work focuses on the application of a pulsed mode, nanosecond Nd:YAG laser system for the surface...

  5. Rapid, single-molecule assays in nano/micro-fluidic chips with arrays of closely spaced parallel channels fabricated by femtosecond laser machining.

    Science.gov (United States)

    Canfield, Brian K; King, Jason K; Robinson, William N; Hofmeister, William H; Davis, Lloyd M

    2014-08-20

    Cost-effective pharmaceutical drug discovery depends on increasing assay throughput while reducing reagent needs. To this end, we are developing an ultrasensitive, fluorescence-based platform that incorporates a nano/micro-fluidic chip with an array of closely spaced channels for parallelized optical readout of single-molecule assays. Here we describe the use of direct femtosecond laser machining to fabricate several hundred closely spaced channels on the surfaces of fused silica substrates. The channels are sealed by bonding to a microscope cover slip spin-coated with a thin film of poly(dimethylsiloxane). Single-molecule detection experiments are conducted using a custom-built, wide-field microscope. The array of channels is epi-illuminated by a line-generating red diode laser, resulting in a line focus just a few microns thick across a 500 micron field of view. A dilute aqueous solution of fluorescently labeled biomolecules is loaded into the device and fluorescence is detected with an electron-multiplying CCD camera, allowing acquisition rates up to 7 kHz for each microchannel. Matched digital filtering based on experimental parameters is used to perform an initial, rapid assessment of detected fluorescence. More detailed analysis is obtained through fluorescence correlation spectroscopy. Simulated fluorescence data is shown to agree well with experimental values.

  6. Intelligent Systems for Stabilizing Mode-Locked Lasers and Frequency Combs: Machine Learning and Equation-Free Control Paradigms for Self-Tuning Optics

    Directory of Open Access Journals (Sweden)

    Kutz J. Nathan

    2015-12-01

    Full Text Available We demonstrate that a software architecture using innovations in machine learning and adaptive control provides an ideal integration platform for self-tuning optics. For mode-locked lasers, commercially available optical telecom components can be integrated with servocontrollers to enact a training and execution software module capable of self-tuning the laser cavity even in the presence of mechanical and/or environmental perturbations, thus potentially stabilizing a frequency comb. The algorithm training stage uses an exhaustive search of parameter space to discover best regions of performance for one or more objective functions of interest. The execution stage first uses a sparse sensing procedure to recognize the parameter space before quickly moving to the near optimal solution and maintaining it using the extremum seeking control protocol. The method is robust and equationfree, thus requiring no detailed or quantitatively accurate model of the physics. It can also be executed on a broad range of problems provided only that suitable objective functions can be found and experimentally measured.

  7. Machining fiber-reinforced composites

    Science.gov (United States)

    Komanduri, Ranga

    1993-04-01

    Compared to high tool wear and high costs of tooling of fiber-reinforced composites (FRCs), noncontact material-removal processes offer attractive alternative. Noncontact machining methods can also minimize dust, noise, and extensive plastic deformation and consequent heat generation associated with conventional machining of FRCs, espacially those with an epoxy matrix. The paper describes the principles involved in and the details of machining of FRCs by laser machining, water jet-cutting and abrasive water jet-cutting, and electrical discharge machining of composites, as well as the limitations of each method.

  8. In vitro culture of individual mouse preimplantation embryos: the role of embryo density, microwells, oxygen, timing and conditioned media.

    Science.gov (United States)

    Kelley, Rebecca L; Gardner, David K

    2017-02-15

    Single embryo culture is suboptimal compared with group culture, but necessary for embryo monitoring, and culture systems should be improved for single embryos. Pronucleate mouse embryos were used to assess the effect of culture conditions on single embryo development. Single culture either before or after compaction reduced cell numbers (112.2 ± 3.1; 110.2 ± 3.5) compared with group culture throughout (127.0 ± 3.4; P media volume from 20 µl to 2 µl increased blastocyst cell numbers in single embryos cultured in 5% oxygen (84.4 ± 3.2 versus 97.8 ± 2.8; P media to single embryos increased hatching rate and blastocyst cell number (91.5 ± 4.7 versus 113.1 ± 4.4; P media volume and microwells influence single embryo development; and embryo-conditioned media may substitute for group culture.

  9. High throughput microwell spectrophotometric assay for olmesartan medoxomil in tablets based on its charge-transfer reaction with DDQ

    Directory of Open Access Journals (Sweden)

    Darwish Ibrahim A.

    2014-03-01

    Full Text Available The study describes the development and validation of a new microwell-based spectrophotometric assay for determination of olmesartan medoxomil (OLM in tablets. The formation of a colored charge-transfer (CT complex between OLM as an n-electron donor and 2,3-dichloro- -5,6-dicyano-1,4-benzoquinone (DDQ as a p-electron acceptor was investigated, and employed as the basis for the development of the new assay. The proposed assay was conducted in 96-microwell plates. The absorbance of the colored-CT complex was measured at 460 nm with a microplate reader. Optimum conditions of the reaction and the analytical procedures of the assay were established. Under the optimum conditions, a linear relationship with a good correlation coefficient was found between the absorbance and the concentration of OLM in the range of 2-200 μg per well. The limits of detection and quantitation were 0.53 and 1.61 μg per well, respectively. No interference was observed from the excipients present in OLM tablets or from hydrochlorothiazide and amlodipine besylate that were co-formulated with OLM in some of its formulations. The assay was successfully applied to the analysis of OLM in tablets with good accuracy and precision. The assay described herein has a great practical value in the routine analysis of OLM in quality control laboratories, since it has a high throughput property and consumes low volumes of organic solvent. It thus offers a reduction in the exposure of analysts to the toxic effects of organic solvents, as well as a reduction in the cost of analysis.

  10. Application of distance-coded reference measuring system on rotary swivel drive of the 3D laser cutting machine%距离编码测量装置在三维激光切割机上的应用

    Institute of Scientific and Technical Information of China (English)

    翟东升; 钟昇; 洪超

    2013-01-01

    The application method of distance-coded reference measuring system on rotary swivel drive of the 3D laser cutting machine has been introduced in the text. The above method and conclusion provide reference for the application of distance-coded reference measuring system on other machine tools.%本文主要介绍带距离编码参考点标记的测量装置在三维激光切割机旋转机构上的应用方法,可为距离编码测量装置的应用提供参考.

  11. Fabrication of microfluidic devices: improvement of surface quality of CO2 laser machined poly(methylmethacrylate) polymer

    Science.gov (United States)

    Mohammed, Mazher I.; Nazrul Hisham Zainal Alam, Muhd; Kouzani, Abbas; Gibson, Ian

    2017-01-01

    Laser engraving has considerable potential for the rapid and cost effective manufacturing of polymeric microfluidic devices. However, fabricated devices are hindered by relatively large surface roughness in the engraved areas, which can perturb smooth fluidic flow and can damage sensitive biological components. This effect is exacerbated when engraving at depths beyond the laser focal range, limiting the production of large aspect ratio devices such as microbioreactors. This work aims to overcome such manufacturing limitations and to realise more reproducible and defect free microfluidic channels and structures. We present a strategy of multiple engraving passes alongside solvent polymer reflow for shallow depth (500 µm) features. To examine the proposed methodologies, capillary action and bioreactor microfluidic devices were fabricated and evaluated. Results indicate that the multiple engraving technique could reproduce engraved microfluidic channels to depths between 50-470 µm, both rapidly (6-8 min) and with low average surface roughness (1.5-2.5 µm). The layer cutting approach was effective at manufacturing microfluidic devices with depths  <500 µm, rapidly (<1 min) and with low surface roughness. Ultimately, the proposed methodology is highly beneficial for the rapid development of polymer-based microfluidic devices.

  12. Rise of the Machines: Automated Laser Guide Star Adaptive Optics Observations of Thousands of Objects with Robo-AO

    Science.gov (United States)

    Riddle, Reed L.; Baranec, C.; Law, N. M.; Tendulkar, S. P.; Ramaprakash, A. N.; Kulkarni, S. R.; Dekany, R.; Bui, K.; Burse, M.; Das, H.; Punnadi, S.; Chordia, P.

    2013-01-01

    Robo-AO is the first fully automated laser guide star adaptive optics instrument. Robo-AO has completed thousands of automated AO observations at the visible diffraction limit for several scientific programs during its first semester of science observations. These programs include: the Ultimate Binarity Survey to examine stellar binarity properties across the main sequence and beyond; a survey of 1,000 Kepler objects of interest; the multiplicity of solar type stars; and several programs for high precision astrometric observations. A new infrared camera is under development for Robo-AO, and a clone of the system is in the planning stages. This presentation will discuss the Robo-AO instrument capabilities, summarize the science programs undertaken, and discuss the future of Robo-AO.

  13. Laser Drilling Practical Applications

    CERN Document Server

    Yilbas, Bekir Sami

    2013-01-01

    This book introduces laser drilling processes including modelling, quality assessment of drilled holes, and laser drilling applications. It provides insights into the laser drilling process and the relation among the drilling parameters pertinent to improved end product quality. This book is written for engineers and scientists working on laser machining, particularly laser drilling.

  14. Characterization of a two-dimensional temperature field within a rapid compression machine using a toluene planar laser-induced fluorescence imaging technique

    Science.gov (United States)

    Strozzi, Camille; Sotton, Julien; Mura, Arnaud; Bellenoue, Marc

    2009-12-01

    The homogeneous charge compression ignition (HCCI) combustion process is an advanced operating mode for automotive engines. The self-ignition mechanisms that occur within the combustion chamber exhibit extreme temperature dependence. Therefore, the thorough understanding of corresponding phenomena requires the use of diagnostic methods featuring a sufficient thermal sensitivity, applicable in severe conditions similar to those encountered within engines. In this respect, toluene planar laser-induced fluorescence (PLIF) is applied to the inert compression flow generated within an optical rapid compression machine (RCM). A relatively simple diagnostic system is retained: a single wavelength excitation device (266 nm) and a single (filtered) collection system. This diagnostic system is associated with an image processing strategy specifically adapted to RCM devices. Despite the severe conditions under consideration (40 bar, 700-950 K), the method allows us to obtain relatively large two-dimensional temperature fields that display a level of description seldom achieved in such devices. In particular the temperature gradients, which play a crucial role in HCCI combustion processes, can be estimated. The present experimental results confirm the good reliability and accuracy of the method. The information gathered with this toluene PLIF method puts in evidence its high potentialities for the study of aero-thermal-reactive processes as they take place in real engine conditions. The retained strategy also brings new possibilities of non-intrusive analysis for flows practically encountered within industrial devices.

  15. Information Contents of a Signal at Repeated Positioning Measurements of the Coordinate Measuring Machine (CMM by Laser Interferometer

    Directory of Open Access Journals (Sweden)

    Stejskal Tomáš

    2016-10-01

    Full Text Available The input of this paper lies in displaying possibilities how to determine the condition of a coordinate measuring machine (CMM based on a large number of repeated measurements. The number of repeated measurements exceeds common requirements for determining positioning accuracy. The total offset in the accuracy of spatial positioning consists of partial inaccuracies of individual axes. 6 basic errors may be defined at each axis. In a triaxial set, that translates into 18 errors, to which an offset from the perpendicularity between the axial pairs must be added. Therefore, the combined number of errors in a single position is 21. These errors are systemic and stem from the machine’s geometry. In addition, there are accidental errors to account for as well. Accidental errors can be attributed to vibrations, mass inertness, passive resistance, and in part to fluctuations in temperature. A peculiar set of systemic errors are time-varying errors. The nature of those errors may be reversible, for instance if they result from influence of temperature or elastic deformation. They can be also irreversible, for example as a result of wear and tear or line clogging, due to loosened connection or permanent deformation of a part post collision. A demonstration of thermal equalizing of the machine’s parts may also be observed in case of failure to adhere to a sufficient time interval from the moment the air-conditioning is turned on. Repeated measurements done on a selected axis with linear interferometer can provide complex information on the CMM condition and also on the machine’s interaction with the given technical environment.

  16. 基于感性工学的激光打标机外观创新设计研究%Research on the Innovation Appearance Design of Laser Marking Machine Based on Kansei Engineering

    Institute of Scientific and Technical Information of China (English)

    陈雪; 张义

    2012-01-01

    结合感性工学系统方法确定激光打标机外观的设计流程与方法,建立了激光打标机的意象语义与形态元素关联,并选取高档与低档意象进行方案设计。通过对方案的调查与评估,其结果验证了感性工学用于激光打标机外观创新设计研究的合理性与有效性,以及研究结论的指导性。%Combined with the appearance design and process of laser marking machine by using Kansei Engineering method.It established the association between image semantic and shape elements of color laser marking machine,and selected high-grade and low-grade image for program design.The result of investigation and evaluation on the program proved the rationality and effectiveness of Kansei Engineering method used in the innovative appearance design research of laser marking machine,and also the guidance of research conclusions.

  17. Application of Laser Tracker in Installation Accuracy Inspection of Continuous Casting Machine%激光跟踪仪在检测连铸机安装精度中的应用

    Institute of Scientific and Technical Information of China (English)

    沈祥开; 向阳

    2014-01-01

    简要介绍了典型连铸机安装部位的精度要求以及目前检测方法的现状,同时介绍了激光跟踪仪的检测原理、方法和精度。主要通过激光跟踪仪在检测连铸机安装精度中的实际应用,在可行性、检测数据及检测耗时方面与现有检测方法进行对比分析,说明了激光跟踪仪在检测连铸机安装精度中的实用性、精准度和高效率。%The installation accuracy requirement and current inspection method of continuous casting ma-chine are introduced simply,the basic principle,inspection method and precision of laser tracker are also intro-duced.Both method are compared in terms of feasibility,inspecting data and measuring time,through the practi-cal application of laser tracker used in installation accuracy inspection of continuous casting machine,explains the laser tracker used in installation accuracy inspection of continuous casting machine is feasibility,accurately and efficiently.

  18. 3-D Simulation of the Temperature Field of Laser-Assisted Machining with FEM%激光辅助切削温度场的三维有限元仿真

    Institute of Scientific and Technical Information of China (English)

    王慧艺; 李从心; 阮雪榆

    2001-01-01

    激光加热的温度场受材料物性参数、工件几何形状、激光器功率、光斑形状及移动速度的影响.分析激光辅助立铣淬硬钢的工况,提出简化的计算模型,进而将非稳态传热方程化为稳态的传热控制方程.应用三维有限元法,对激光流动加热45#钢的温度场进行了仿真.经对比不同光斑形状、移动速度、光斑温度对温度场的影响,归纳了激光加热的特点,对激光辅助加工工艺参数的选择提出了建议.%Since the temperature field heated by moving laser is a huge gradient on space and time, it is not able to get a convincing result by experiments. However, it can be reproduced by 3-D simulation technology. Many factors affect the temperature field, like the material properties, geometry shape of a part, laser power, focus shape and moving rate. Based on laser-assisted milling of hardened steel, a simplified calculation model was suggested. Furthermore, the control equation of conduction was changed into static from dynamic. The temperature fields of 45# heated by moving laser was simulated with FEM and the different laser focus shapes, moving rates and temperatures were studied. The features of laser heating were concluded and the machining parameters of laser-assisted machining was suggested.

  19. Rise of the machines: first year operations of the Robo-AO visible-light laser-adaptive optics instrument

    CERN Document Server

    Baranec, Christoph; Law, Nicholas M; Ramaprakash, A N; Tendulkar, Shriharsh; Hogstrom, Kristina; Bui, Khanh; Burse, Mahesh; Chordia, Pravin; Das, Hillol; Dekany, Richard; Kulkarni, Shrinivas; Punnadi, Sujit; Smith, Roger

    2013-01-01

    Robo-AO is the first autonomous laser adaptive optics system and science instrument operating on sky. With minimal human oversight, the system robotically executes large scale surveys, monitors long-term astrophysical dynamics and characterizes newly discovered transients, all at the visible diffraction limit. The average target-to target operational overhead, including slew time, is a mere 86 s, enabling up to ~20 observations per hour. The first of many envisioned systems went live in June 2012, and has since finished 78 nights of science observing at the Palomar Observatory 60-inch (1.5 m) telescope, with over 9,000 robotic observations executed as of August 2013. The system will be augmented in 2014 with a low-noise wide field infrared camera, which will double as a tip-tilt sensor, to widen the spectral bandwidth of observations, increase available sky coverage as well as enable deeper visible imaging using adaptive-optics sharpened infrared tip-tilt guide sources.

  20. Rise of The Machines: First Year Operations of The Robo-AO Visible-Light Laser-Adaptive-Optics Instrument

    Science.gov (United States)

    Baranec, C.; Riddle, R.; Law, N.; Ramaprakash, A. N.; Tendulkar, S.; Hogstrom, K.; Bui, K.; Burse, M.; Chordia, P.; Das, H.; Dekany, R.

    2013-09-01

    Robo-AO is the first autonomous laser adaptive optics system and science instrument operating on sky. With minimal human oversight, the system robotically executes large scale surveys, monitors long-term astrophysical dynamics and characterizes newly discovered transients, all at the visible diffraction limit. The average target-to-target operational overhead, including slew time, is a mere 86 s, enabling up to ~200 observations per night. The first of many envisioned systems went live in June 2012, and has since finished 51 nights of science observing at the Palomar Observatory 60-inch (1.5 m) telescope, with over 5,600 robotic observations executed as of March 2013. The system will be augmented in late 2013 with a low-noise wide field infrared camera, which will double as a tip-tilt sensor, to widen the spectral bandwidth of observations, increase available sky coverage as well as enable deeper visible imaging using adaptive-optics sharpened infrared tip-tilt guide sources.

  1. A new approach to theoretical investigations of high harmonics generation by means of fs laser interaction with overdense plasma layers. Combining particle-in-cell simulations with machine learning.

    Science.gov (United States)

    Mihailescu, A.

    2016-12-01

    Within the past decade, various experimental and theoretical investigations have been performed in the field of high-order harmonics generation (HHG) by means of femtosecond (fs) laser pulses interacting with laser produced plasmas. Numerous potential future applications thus arise. Beyond achieving higher conversion efficiency for higher harmonic orders and hence harmonic power and brilliance, there are more ambitious scientific goals such as attaining shorter harmonic wavelengths or reducing harmonic pulse durations towards the attosecond and even the zeptosecond range. High order harmonics are also an attractive diagnostic tool for the laser-plasma interaction process itself. Particle-in-Cell (PIC) simulations are known to be one of the most important numerical instruments employed in plasma physics and in laser-plasma interaction investigations. The novelty brought by this paper consists in combining the PIC method with several machine learning approaches. For predictive modelling purposes, a universal functional approximator is used, namely a multi-layer perceptron (MLP), in conjunction with a self-organizing map (SOM). The training sets have been retrieved from the PIC simulations and also from the available literature in the field. The results demonstrate the potential utility of machine learning in predicting optimal interaction scenarios for gaining higher order harmonics or harmonics with particular features such as a particular wavelength range, a particular harmonic pulse duration or a certain intensity. Furthermore, the author will show how machine learning can be used for estimations of electronic temperatures, proving that it can be a reliable tool for obtaining better insights into the fs laser interaction physics.

  2. Machine Translation

    Institute of Scientific and Technical Information of China (English)

    张严心

    2015-01-01

    As a kind of ancillary translation tool, Machine Translation has been paid increasing attention to and received different kinds of study by a great deal of researchers and scholars for a long time. To know the definition of Machine Translation and to analyse its benefits and problems are significant for translators in order to make good use of Machine Translation, and helpful to develop and consummate Machine Translation Systems in the future.

  3. Sustainable machining

    CERN Document Server

    2017-01-01

    This book provides an overview on current sustainable machining. Its chapters cover the concept in economic, social and environmental dimensions. It provides the reader with proper ways to handle several pollutants produced during the machining process. The book is useful on both undergraduate and postgraduate levels and it is of interest to all those working with manufacturing and machining technology.

  4. Calibration of a Parallel Kinematic Machine Tool

    Institute of Scientific and Technical Information of China (English)

    HE Xiao-mei; DING Hong-sheng; FU Tie; XIE Dian-huang; XU Jin-zhong; LI Hua-feng; LIU Hui-lin

    2006-01-01

    A calibration method is presented to enhance the static accuracy of a parallel kinematic machine tool by using a coordinate measuring machine and a laser tracker. According to the established calibration model and the calibration experiment, the factual 42 kinematic parameters of BKX-I parallel kinematic machine tool are obtained. By circular tests the comparison is made between the calibrated and the uncalibrated parameters and shows that there is 80% improvement in accuracy of this machine tool.

  5. Application of Various Lasers to Laser Trimming Resistance System

    Institute of Scientific and Technical Information of China (English)

    SUN Ji-feng

    2007-01-01

    Though the laser trimming resistance has been an old laser machining industry for over 30 years, the development of technology brings new alternative lasers which can be used for the traditional machining. The paper describes application of various lasers to laser trimming resistance system including early traditional krypton arc lamp pumped Nd:YAG to laser, modern popular diode pumped solid state laser and the present advanced harmonic diode pumped solid state laser. Using the new alternative lasers in the laser trimming resistance system can dramatically improve the yields and equipment performance.

  6. Investigation of Surfaces after Non Conventional Machining

    Science.gov (United States)

    Micietova, Anna; Neslusan, Miroslav; Cillikova, Maria

    2016-12-01

    This paper deals with analysis of surface integrity of steel after electro discharge machining (EDM), water jet machining, (WJM) laser beam machining (LBM) and plasma beam machining (PBM). The paper discusses surface integrity expressed in surface roughness, sample precision expressed in perpendicularity deviation as well as stress state. This study also demonstrates influence of the various non-conventional methods on structure transformations and reports about sensitivity of the different non-conventional methods of machining with regard to variable thickness of machined samples.

  7. A study of machine learning regression methods for major elemental analysis of rocks using laser-induced breakdown spectroscopy

    Science.gov (United States)

    Boucher, Thomas F.; Ozanne, Marie V.; Carmosino, Marco L.; Dyar, M. Darby; Mahadevan, Sridhar; Breves, Elly A.; Lepore, Kate H.; Clegg, Samuel M.

    2015-05-01

    The ChemCam instrument on the Mars Curiosity rover is generating thousands of LIBS spectra and bringing interest in this technique to public attention. The key to interpreting Mars or any other types of LIBS data are calibrations that relate laboratory standards to unknowns examined in other settings and enable predictions of chemical composition. Here, LIBS spectral data are analyzed using linear regression methods including partial least squares (PLS-1 and PLS-2), principal component regression (PCR), least absolute shrinkage and selection operator (lasso), elastic net, and linear support vector regression (SVR-Lin). These were compared against results from nonlinear regression methods including kernel principal component regression (K-PCR), polynomial kernel support vector regression (SVR-Py) and k-nearest neighbor (kNN) regression to discern the most effective models for interpreting chemical abundances from LIBS spectra of geological samples. The results were evaluated for 100 samples analyzed with 50 laser pulses at each of five locations averaged together. Wilcoxon signed-rank tests were employed to evaluate the statistical significance of differences among the nine models using their predicted residual sum of squares (PRESS) to make comparisons. For MgO, SiO2, Fe2O3, CaO, and MnO, the sparse models outperform all the others except for linear SVR, while for Na2O, K2O, TiO2, and P2O5, the sparse methods produce inferior results, likely because their emission lines in this energy range have lower transition probabilities. The strong performance of the sparse methods in this study suggests that use of dimensionality-reduction techniques as a preprocessing step may improve the performance of the linear models. Nonlinear methods tend to overfit the data and predict less accurately, while the linear methods proved to be more generalizable with better predictive performance. These results are attributed to the high dimensionality of the data (6144 channels

  8. GPC Light Shaper for energy efficient laser materials processing

    DEFF Research Database (Denmark)

    Bañas, Andrew Rafael; Palima, Darwin; Villangca, Mark Jayson

    The biggest use of lasers is in materials processing. In manufacturing, lasers are used for cutting, drilling, marking and other machining processes. Similarly, lasers are important in microfabrication processes such as photolithography, direct laser writing, or ablation. Lasers are advantageous...

  9. [Lasers].

    Science.gov (United States)

    Passeron, T

    2012-11-01

    Lasers are a very effective approach for treating many hyperpigmented lesions. They are the gold standard treatment for actinic lentigos and dermal hypermelanocytosis, such as Ota nevus. Becker nevus, hyperpigmented mosaicisms, and lentigines can also be successfully treated with lasers, but they could be less effective and relapses can be observed. However, lasers cannot be proposed for all types of hyperpigmentation. Thus, freckles and café-au-lait macules should not be treated as the relapses are nearly constant. Due to its complex pathophysiology, melasma has a special place in hyperpigmented dermatoses. Q-switched lasers (using standard parameters or low fluency) should not be used because of consistent relapses and the high risk of post-inflammatory hyperpigmentation. Paradoxically, targeting the vascular component of the melasma lesion with lasers could have a beneficial effect. However, these results have yet to be confirmed. In all cases, a precise diagnosis of the type of hyperpigmentation is mandatory before any laser treatment, and the limits and the potential side effects of the treatment must be clearly explained to patients. Copyright © 2012 Elsevier Masson SAS. All rights reserved.

  10. Lasers.

    Science.gov (United States)

    Passeron, T

    2012-12-01

    Lasers are a very effective approach for treating many hyperpigmented lesions. They are the gold standard treatment for actinic lentigos and dermal hypermelanocytosis, such as Ota nevus. Becker nevus, hyperpigmented mosaicisms, and lentigines can also be successfully treated with lasers, but they could be less effective and relapses can be observed. However, lasers cannot be proposed for all types of hyperpigmentation. Thus, freckles and café-au-lait macules should not be treated as the relapses are nearly constant. Due to its complex pathophysiology, melasma has a special place in hyperpigmented dermatoses. Q-switched lasers (using standard parameters or low fluency) should not be used because of consistent relapses and the high risk of post-inflammatory hyperpigmentation. Paradoxically, targeting the vascular component of the melasma lesion with lasers could have a beneficial effect. However, these results have yet to be confirmed. In all cases, a precise diagnosis of the type of hyperpigmentation is mandatory before any laser treatment, and the limits and the potential side effects of the treatment must be clearly explained to patients. Copyright © 2012 Elsevier Masson SAS. All rights reserved.

  11. 激光干涉仪在数控机床维修中的应用研究%Research on Laser Interferometer Application in NC Machine Tool Maintenance

    Institute of Scientific and Technical Information of China (English)

    程志; 张翔

    2014-01-01

    Working principle of the laser interferometer in introduced, the application of laser in-terferometer linear measurement in the NC machine tool maintenance is discussed. For different breakdown of NC machine tools, detected graphics and data are different. Through the graphic and data analysis, NC machine break-down reason should be investigated as soon as possible, which will improve maintenance efifciency.%介绍激光干涉仪工作原理,着重讲述激光干涉仪线性测量在数控机床维修中的应用。对于不同数控机床所出现的故障,检测出的图形和数据各不相同,通过对图形和数据进行分析,以尽快查明数控机床故障原因,提高维修效率。

  12. Study on Identification of Error for the NC Machine Tools Based on Laser Doppler Anemometer%基于激光多普勒仪的数控机床误差辨识

    Institute of Scientific and Technical Information of China (English)

    甘彬; 刘洋; 赵宇

    2013-01-01

    In response to laser Doppler anemometer characteristics of high precision linear displacement measurement of CNC machine tools, this paper introduced the use of laser Doppler anemometer on the NC machine tool error detection and identification method, explained the identification principle in detail and set up the method of error detection model. In order to reduce the machine error, we provide measurement method and basis of the compensation.%针对激光多普勒仪对数控机床线位移测量精度高的特点,介绍了利用激光多普勒仪对数控机床进行误差检测和辨识的方法,阐述了该方法的几何误差辨识原理,并建立了基于该方法的误差检测数学模型.为减小机床误差提供了测量方法和补偿依据.

  13. Verification of a characterization method of the laser-induced selective activation based on industrial lasers

    DEFF Research Database (Denmark)

    Zhang, Yang; Hansen, Hans Nørgaard; Tang, Peter T.

    2013-01-01

    In this article, laser-induced selective activation (LISA) for subsequent autocatalytic copper plating is performed by several types of industrial scale lasers, including a Nd:YAG laser, a UV laser, a fiber laser, a green laser, and a short pulsed laser. Based on analysis of all the laser-machine...

  14. Diamond turning machine controller implementation

    Energy Technology Data Exchange (ETDEWEB)

    Garrard, K.P.; Taylor, L.W.; Knight, B.F.; Fornaro, R.J.

    1988-12-01

    The standard controller for a Pnuemo ASG 2500 Diamond Turning Machine, an Allen Bradley 8200, has been replaced with a custom high-performance design. This controller consists of four major components. Axis position feedback information is provided by a Zygo Axiom 2/20 laser interferometer with 0.1 micro-inch resolution. Hardware interface logic couples the computers digital and analog I/O channels to the diamond turning machine`s analog motor controllers, the laser interferometer, and other machine status and control information. It also provides front panel switches for operator override of the computer controller and implement the emergency stop sequence. The remaining two components, the control computer hardware and software, are discussed in detail below.

  15. Simple machines

    CERN Document Server

    Graybill, George

    2007-01-01

    Just how simple are simple machines? With our ready-to-use resource, they are simple to teach and easy to learn! Chocked full of information and activities, we begin with a look at force, motion and work, and examples of simple machines in daily life are given. With this background, we move on to different kinds of simple machines including: Levers, Inclined Planes, Wedges, Screws, Pulleys, and Wheels and Axles. An exploration of some compound machines follows, such as the can opener. Our resource is a real time-saver as all the reading passages, student activities are provided. Presented in s

  16. Interfacing microwells with nanoliter compartments: a sampler generating high-resolution concentration gradients for quantitative biochemical analyses in droplets.

    Science.gov (United States)

    Gielen, Fabrice; Buryska, Tomas; Van Vliet, Liisa; Butz, Maren; Damborsky, Jiri; Prokop, Zbynek; Hollfelder, Florian

    2015-01-06

    Analysis of concentration dependencies is key to the quantitative understanding of biological and chemical systems. In experimental tests involving concentration gradients such as inhibitor library screening, the number of data points and the ratio between the stock volume and the volume required in each test determine the quality and efficiency of the information gained. Titerplate assays are currently the most widely used format, even though they require microlitre volumes. Compartmentalization of reactions in pico- to nanoliter water-in-oil droplets in microfluidic devices provides a solution for massive volume reduction. This work addresses the challenge of producing microfluidic-based concentration gradients in a way that every droplet represents one unique reagent combination. We present a simple microcapillary technique able to generate such series of monodisperse water-in-oil droplets (with a frequency of up to 10 Hz) from a sample presented in an open well (e.g., a titerplate). Time-dependent variation of the well content results in microdroplets that represent time capsules of the composition of the source well. By preserving the spatial encoding of the droplets in tubing, each reactor is assigned an accurate concentration value. We used this approach to record kinetic time courses of the haloalkane dehalogenase DbjA and analyzed 150 combinations of enzyme/substrate/inhibitor in less than 5 min, resulting in conclusive Michaelis-Menten and inhibition curves. Avoiding chips and merely requiring two pumps, a magnetic plate with a stirrer, tubing, and a pipet tip, this easy-to-use device rivals the output of much more expensive liquid handling systems using a fraction (∼100-fold less) of the reagents consumed in microwell format.

  17. Electric machine

    Science.gov (United States)

    El-Refaie, Ayman Mohamed Fawzi [Niskayuna, NY; Reddy, Patel Bhageerath [Madison, WI

    2012-07-17

    An interior permanent magnet electric machine is disclosed. The interior permanent magnet electric machine comprises a rotor comprising a plurality of radially placed magnets each having a proximal end and a distal end, wherein each magnet comprises a plurality of magnetic segments and at least one magnetic segment towards the distal end comprises a high resistivity magnetic material.

  18. Nontraditional machining processes research advances

    CERN Document Server

    2013-01-01

    Nontraditional machining employs processes that remove material by various methods involving thermal, electrical, chemical and mechanical energy or even combinations of these. Nontraditional Machining Processes covers recent research and development in techniques and processes which focus on achieving high accuracies and good surface finishes, parts machined without burrs or residual stresses especially with materials that cannot be machined by conventional methods. With applications to the automotive, aircraft and mould and die industries, Nontraditional Machining Processes explores different aspects and processes through dedicated chapters. The seven chapters explore recent research into a range of topics including laser assisted manufacturing, abrasive water jet milling and hybrid processes. Students and researchers will find the practical examples and new processes useful for both reference and for developing further processes. Industry professionals and materials engineers will also find Nontraditional M...

  19. 数控激光切割机XY工作台传动系统设计%Transmission System Design of XY Worktable of CNC Laser Cutting Machine

    Institute of Scientific and Technical Information of China (English)

    刘晨敏; 杜木伟; 张旭

    2012-01-01

    Based on the laser cutting mechanism and the working principle of CNC laser cutting machine, the feeding transmission system of mechanical part XY worktable is analyzed, and the transmission system of a rotating motor driving screw-nut through a pair of spur gears is designed.%依据激光切割技术原理及数控激光切割机的工作原理,分析了机械部分XY工作台的进给传动系统,设计了由旋转电机通过一对直齿轮传至丝杠螺母的传动系统.

  20. The Machine within the Machine

    CERN Multimedia

    Katarina Anthony

    2014-01-01

    Although Virtual Machines are widespread across CERN, you probably won't have heard of them unless you work for an experiment. Virtual machines - known as VMs - allow you to create a separate machine within your own, allowing you to run Linux on your Mac, or Windows on your Linux - whatever combination you need.   Using a CERN Virtual Machine, a Linux analysis software runs on a Macbook. When it comes to LHC data, one of the primary issues collaborations face is the diversity of computing environments among collaborators spread across the world. What if an institute cannot run the analysis software because they use different operating systems? "That's where the CernVM project comes in," says Gerardo Ganis, PH-SFT staff member and leader of the CernVM project. "We were able to respond to experimentalists' concerns by providing a virtual machine package that could be used to run experiment software. This way, no matter what hardware they have ...

  1. Machine learning methods for nanolaser characterization

    CERN Document Server

    Zibar, Darko; Winther, Ole; Moerk, Jesper; Schaeffer, Christian

    2016-01-01

    Nanocavity lasers, which are an integral part of an on-chip integrated photonic network, are setting stringent requirements on the sensitivity of the techniques used to characterize the laser performance. Current characterization tools cannot provide detailed knowledge about nanolaser noise and dynamics. In this progress article, we will present tools and concepts from the Bayesian machine learning and digital coherent detection that offer novel approaches for highly-sensitive laser noise characterization and inference of laser dynamics. The goal of the paper is to trigger new research directions that combine the fields of machine learning and nanophotonics for characterizing nanolasers and eventually integrated photonic networks

  2. Machine learning techniques in optical communication

    DEFF Research Database (Denmark)

    Zibar, Darko; Piels, Molly; Jones, Rasmus Thomas

    2015-01-01

    Techniques from the machine learning community are reviewed and employed for laser characterization, signal detection in the presence of nonlinear phase noise, and nonlinearity mitigation. Bayesian filtering and expectation maximization are employed within nonlinear state-space framework...

  3. Fabrication of a gas sensor array with micro-wells for VOCs gas sensing based on polymer/carbon nanotube thin films

    Science.gov (United States)

    Xie, Guangzhong; Xie, Tao; Zhu, Tao; Jiang, Yadong; Tai, Huiling

    2014-08-01

    In this paper, gas sensor array with micro-well was designed and prepared by Micro Electro-Mechanical Systems (MEMS) technology. The micro-well and interdigital electrodes of sensor array were prepared using photolithography process, reactive ion etching (RIE) process, wet etching and conventional vacuum evaporation. In the manufacture process of the gas sensor array, KOH wet etching process was mainly discussed. The optimum etching processing parameters were as follows: 30 wt% KOH solution at 80 °C, a cooling back-flow device and a magnetic stirrer. The multi-walled carbon nanotubes (MWCNTs)-polyethyleneoxide (PEO) and MWNTs-Polyvinylpyrrolidone (PVP) composite films were utilized as sensitive layers to test gas-sensing properties. Response performances of MWCNTs- PEO and MWNTs-PVP composite films to toluene vapor and methanol vapor at room temperature were investigated. The results revealed that the sensor array showed a larger sensitivity to toluene vapor than to methanol vapor. In addition, the sensing mechanisms were studied as well.

  4. Reproducible Construction of Surface Tension-Mediated Honeycomb Concave Microwell Arrays for Engineering of 3D Microtissues with Minimal Cell Loss.

    Science.gov (United States)

    Lee, GeonHui; Lee, JaeSeo; Oh, HyunJik; Lee, SangHoon

    2016-01-01

    The creation of engineered 3D microtissues has attracted prodigious interest because of the fact that this microtissue structure is able to mimic in vivo environments. Such microtissues can be applied extensively in the fields of regenerative medicine and tissue engineering, as well as in drug and toxicity screening. Here, we develop a novel method of fabricating a large number of dense honeycomb concave microwells via surface tension-mediated self-construction. More specifically, in order to control the curvature and shape of the concavity in a precise and reproducible manner, a custom-made jig system was designed and fabricated. By applying a pre-set force using the jig system, the shape of the honeycomb concave well was precisely and uniformly controlled, despite the fact that wells were densely packed. The thin wall between the honeycomb wells enables the minimization of cell loss during the cell-seeding process. To evaluate the performance of the honeycomb microwell array, rat hepatocytes were seeded, and spheroids were successfully formed with uniform shape and size. Liver-specific functions such as albumin secretion and cytochrome P450 were subsequently analyzed. The proposed method of fabricating honeycomb concave wells is cost-effective, simple, and reproducible. The honeycomb well array can produce multiple spheroids with minimal cell loss, and can lead to significant contributions in tissue engineering and organ regeneration.

  5. Machine Learning

    CERN Document Server

    CERN. Geneva

    2017-01-01

    Machine learning, which builds on ideas in computer science, statistics, and optimization, focuses on developing algorithms to identify patterns and regularities in data, and using these learned patterns to make predictions on new observations. Boosted by its industrial and commercial applications, the field of machine learning is quickly evolving and expanding. Recent advances have seen great success in the realms of computer vision, natural language processing, and broadly in data science. Many of these techniques have already been applied in particle physics, for instance for particle identification, detector monitoring, and the optimization of computer resources. Modern machine learning approaches, such as deep learning, are only just beginning to be applied to the analysis of High Energy Physics data to approach more and more complex problems. These classes will review the framework behind machine learning and discuss recent developments in the field.

  6. Single Chip Microcomputer Control System of Laser Engraving Machine with Membrane Resistance%薄膜电阻激光修刻机的单片机控制系统

    Institute of Scientific and Technical Information of China (English)

    俞志根

    2015-01-01

    Membrane resistance is a core component of the potentiometer type Angle displacement sensor,directly affect the output of the sen-sor performance.High precision of angular displacement sensor membrane resistance requires precision carving.A laser carving machine con-sists of the mechanical noumenon,single chip microcomputer control part and the control software.We can use STC12C5410 SCM as the core design of laser membrane resistance engraving machine control system,is composed of single chip computer,stepping motor,laser and a number of cylinders,to control the workbench automatically fix the engraved and membrane resistance automatically feed,can achieve 0. 05 0.5% adjustable precision carving,repairing time velocity of every 1 to 2 minutes.%薄膜电阻是电位器式角位移传感器的核心构件,直接影响传感器的输出性能,高精度角位移传感器的薄膜电阻需要进行精密的修刻,激光修刻机包括机械本体、单片机控制部分和控制软件组成。采用 STC12C5410单片机为核心设计的薄膜电阻激光修刻机控制系统,由单片机、步进电机、激光器和若干辅件组成,来控制修刻工作台的自动修刻和薄膜电阻的自动进给,能实现0.050.5%可调节修刻精度,每个24分钟的修刻速度。

  7. Machine Tool Advanced Skills Technology (MAST). Common Ground: Toward a Standards-Based Training System for the U.S. Machine Tool and Metal Related Industries. Volume 13: Laser Machining, of a 15-Volume Set of Skill Standards and Curriculum Training Materials for the Precision Manufacturing Industry.

    Science.gov (United States)

    Texas State Technical Coll., Waco.

    This document is intended to help education and training institutions deliver the Machine Tool Advanced Skills Technology (MAST) curriculum to a variety of individuals and organizations. MAST consists of industry-specific skill standards and model curricula for 15 occupational specialty areas within the U.S. machine tool and metals-related…

  8. Spheroid Coculture of Hematopoietic Stem/Progenitor Cells and Monolayer Expanded Mesenchymal Stem/Stromal Cells in Polydimethylsiloxane Microwells Modestly Improves In Vitro Hematopoietic Stem/Progenitor Cell Expansion.

    Science.gov (United States)

    Futrega, Kathryn; Atkinson, Kerry; Lott, William B; Doran, Michael R

    2017-04-01

    While two-dimensional (2D) monolayers of mesenchymal stem/stromal cells (MSCs) have been shown to enhance hematopoietic stem/progenitor cell (HSPC) expansion in vitro, expanded cells do not engraft long term in human recipients. This outcome is attributed to the failure of 2D culture to recapitulate the bone marrow (BM) niche signal milieu. Herein, we evaluated the capacity of a novel three-dimensional (3D) coculture system to support HSPC expansion in vitro. A high-throughput polydimethylsiloxane (PDMS) microwell platform was used to manufacture thousands of uniform 3D multicellular coculture spheroids. Relative gene expression in 3D spheroid versus 2D adherent BM-derived MSC cultures was characterized and compared with literature reports. We evaluated coculture spheroids, each containing 25-400 MSCs and 10 umbilical cord blood (CB)-derived CD34(+) progenitor cells. At low exogenous cytokine concentrations, 2D and 3D MSC coculture modestly improved overall hematopoietic cell and CD34(+) cell expansion outcomes. By contrast, a substantial increase in CD34(+)CD38(-) cell yield was observed in PDMS microwell cultures, regardless of the presence or absence of MSCs. This outcome indicated that CD34(+)CD38(-) cell culture yield could be increased using the microwell platform alone, even without MSC coculture support. We found that the increase in CD34(+)CD38(-) cell yield observed in PDMS microwell cultures did not translate to enhanced engraftment in NOD/SCID gamma (NSG) mice or a modification in the relative human hematopoietic lineages established in engrafted mice. In summary, there was no statistical difference in CD34(+) cell yield from 2D or 3D cocultures, and MSC coculture support provided only modest benefit in either geometry. While the high-throughput 3D microwell platform may provide a useful model system for studying cells in coculture, further optimization will be required to generate HSPC yields suitable for use in clinical applications.

  9. Machine Learning

    Energy Technology Data Exchange (ETDEWEB)

    Chikkagoudar, Satish; Chatterjee, Samrat; Thomas, Dennis G.; Carroll, Thomas E.; Muller, George

    2017-04-21

    The absence of a robust and unified theory of cyber dynamics presents challenges and opportunities for using machine learning based data-driven approaches to further the understanding of the behavior of such complex systems. Analysts can also use machine learning approaches to gain operational insights. In order to be operationally beneficial, cybersecurity machine learning based models need to have the ability to: (1) represent a real-world system, (2) infer system properties, and (3) learn and adapt based on expert knowledge and observations. Probabilistic models and Probabilistic graphical models provide these necessary properties and are further explored in this chapter. Bayesian Networks and Hidden Markov Models are introduced as an example of a widely used data driven classification/modeling strategy.

  10. High-throughput microwell plate for cell research%高通量细胞培养芯片的设计及应用

    Institute of Scientific and Technical Information of China (English)

    杜岗; 黄正一; 常青; 李自成

    2014-01-01

    作者设计了一种简单的、不需要复杂管道和动力泵的细胞培养芯片。通过这种芯片可以精确地观察单个或几个细胞的增殖、凋亡的过程,在自动显微成像的帮助下可以详细记录单个细胞对药物的反应等。这种芯片可以在普通的实验室设计和制作,可以放在小的培养皿中,所以很容易把它放到培养箱,从而使细胞有一个稳定的生长环境。作者以PC-12细胞为例,观察了该细胞在这种培养芯片中的生长、增殖和凋亡的过程,证明了这种设计的可行性。同时,这种细胞培养芯片可以很大程度上节约细胞标本和试剂的应用,比较适合稀少样本或者试剂昂贵的细胞学实验。%We developed a novel simple microwell plate that allows researchers to culture cells on chips easily without the use of tubes and pumps for studies of cell proliferation, apoptosis and pharmacology. Unlike any other previous design, this device can be put into an incubator directly and maintains cells in an environment with stable temperature, humidity, air pressure, oxygen and CO2 concentration. We cultured PC-12 cells in these microwell plates and measured the cell proliferation and apoptosis. The microwell plate is recommended for use in all research including those involving rare samples and expensive reagents.

  11. Application of Laser Dual-positioning System in C-arm X Ray Machine%激光双定位系统在C型臂X线机中的应用

    Institute of Scientific and Technical Information of China (English)

    徐可伟; 张超群; 吴向阳

    2011-01-01

    A laser dual- positioning system available in c-arm X ray machine is introduced, which can perform advance positioning through the "cross shaped" laser beam formed by two sets of laser sets mounted respectively at both tube side and intensifier side of the c-arm. The positioning deviations measured in its equivalent model are presented, and the factors leading to these deviations are analyzed.[Chinese Medical Equipment Journal,2011,32(8): 129-130]%阐述了通过在C型臂X线机的球管侧和增强器侧分别安装2个激光器,利用激光形成的"十字交叉"进行预先定位的激光双定位系统方案,通过等效模型测量了定位误差并分析了产生误差的原因及缩小误差的方法.

  12. Laser Physics and Laser Techniques

    Science.gov (United States)

    1989-06-01

    Other types of laser-assisted materials process- Planck Institute for Quantum Optics. Garching . West ing and machining, including laser cutting, welding...detectors with microstructured electrodes, 134[ G. N. Maracas. G. L. Harrs, C. A. Lee. and R. A. McFarlane. Opt. Le’tt., vol. 7, pp. 575-577, Dcc . 1982...A. E. Siegman Max-Planck Institut f’r Quantenoptik, D-8046 Garching , West Germany and E. L. Ginzton Laboratory, Stanford University, Stanford

  13. Machine testning

    DEFF Research Database (Denmark)

    De Chiffre, Leonardo

    This document is used in connection with a laboratory exercise of 3 hours duration as a part of the course GEOMETRICAL METROLOGY AND MACHINE TESTING. The exercise includes a series of tests carried out by the student on a conventional and a numerically controled lathe, respectively. This document...

  14. Representational Machines

    DEFF Research Database (Denmark)

    Petersson, Dag; Dahlgren, Anna; Vestberg, Nina Lager

    to the enterprises of the medium. This is the subject of Representational Machines: How photography enlists the workings of institutional technologies in search of establishing new iconic and social spaces. Together, the contributions to this edited volume span historical epochs, social environments, technological...

  15. Pancreas development ex vivo: culturing embryonic pancreas explants on permeable culture inserts, with fibronectin-coated glass microwells, or embedded in three-dimensional Matrigel™.

    Science.gov (United States)

    Shih, Hung Ping; Sander, Maike

    2014-01-01

    Pancreas development is a complex and dynamic process orchestrated by cellular and molecular events, including morphogenesis and cell differentiation. As a result of recent explorations into possible cell-therapy-based treatments for diabetes, researchers have made significant progress in deciphering the developmental program of pancreas formation. In vitro pancreas organ culture systems provide a valuable tool for exploring the mechanisms of gene regulation, cellular behaviors, and cell differentiation. In this chapter, we review three common techniques for culturing embryonic pancreas explants. Each technique is suitable for different applications. Specifically, culturing embryonic pancreas on culture inserts provides an excellent platform to test the effects of chemical compounds. Conversely, when the embryonic pancreas is cultured in fibronectin-coated glass microwells, the system provides unique culture conditions to monitor organ growth and cellular dynamic events. Lastly, when the embryonic pancreas is embedded in Matrigel, organogenesis can be studied in a three-dimensional environment instead of limiting the analysis to one plane.

  16. Use of response surface methodology for development of new microwell-based spectrophotometric method for determination of atrovastatin calcium in tablets

    Directory of Open Access Journals (Sweden)

    Wani Tanveer A

    2012-11-01

    Full Text Available Abstract Background Response surface methodology by Box–Behnken design employing the multivariate approach enables substantial improvement in the method development using fewer experiments, without wastage of large volumes of organic solvents, which leads to high analysis cost. This methodology has not been employed for development of a method for analysis of atorvastatin calcium (ATR-Ca. Results The present research study describes the use of in optimization and validation of a new microwell-based UV-Visible spectrophotometric method of for determination of ATR-Ca in its tablets. By the use of quadratic regression analysis, equations were developed to describe the behavior of the response as simultaneous functions of the selected independent variables. Accordingly, the optimum conditions were determined which included concentration of 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ, time of reaction and temperature. The absorbance of the colored-CT complex was measured at 460 nm by microwell-plate absorbance reader. The method was validated, in accordance with ICH guidelines for accuracy, precision, selectivity and linearity (r² = 0.9993 over the concentration range of 20–200 μg/ml. The assay was successfully applied to the analysis of ATR-Ca in its pharmaceutical dosage forms with good accuracy and precision. Conclusion The assay described herein has great practical value in the routine analysis of ATR-Ca in quality control laboratories, as it has high throughput property, consumes minimum volume of organic solvent thus it offers the reduction in the exposures of the analysts to the toxic effects of organic solvents, environmentally friendly "Green" approach and reduction in the analysis cost by 50-fold.

  17. Adding machine and calculating machine

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    In 1642 the French mathematician Blaise Pascal(1623-1662) invented a machine;.that could add and subtract. It had.wheels that each had: 1 to 10 marked off along its circumference. When the wheel at the right, representing units, made one complete circle, it engaged the wheel to its left, represents tens, and moved it forward one notch.

  18. Genesis machines

    CERN Document Server

    Amos, Martyn

    2014-01-01

    Silicon chips are out. Today's scientists are using real, wet, squishy, living biology to build the next generation of computers. Cells, gels and DNA strands are the 'wetware' of the twenty-first century. Much smaller and more intelligent, these organic computers open up revolutionary possibilities. Tracing the history of computing and revealing a brave new world to come, Genesis Machines describes how this new technology will change the way we think not just about computers - but about life itself.

  19. Application of Laser Cutting Technology in Machining%激光切割工艺在机械加工中的应用

    Institute of Scientific and Technical Information of China (English)

    齐忠军; 李晓明; 王涛

    2014-01-01

    As a new processing technology of the information age, laser processing plays an increasingly important role in improving product quality, labor productivity, and reducing material consumption. This paper expounds the principle and classification of laser cut-ting, makes comparisons between laser cutting process and traditional cutting, and analyzes the application trend of laser cutting process-ing technique and its future development.%激光加工作为信息时代的新型加工工艺,在提高产品质量、提高劳动生产率、减少材料消耗等方面具有越来越重要的作用。阐述激光切割的原理与分类,对比激光切割工艺与传统切割工艺的不同,分析激光切割加工工艺的应用情况及发展趋势。

  20. 高速激光切割机床数控系统研究%Study on the numerical control system for laser cutting machine

    Institute of Scientific and Technical Information of China (English)

    潘冬

    2014-01-01

    随着经济的迅速发展,我国工业技术也有了较大的改善。现如今切割技术也有了很大的创新改进,新兴的激光切割,它目前已成为热切割技术发展的热点之一,激光切割技术相比较传统切割技术多了高精度、高效率、低污染等优点。为了满足激光切割装备的数字化、精密化等要求,实现此种技术的国产化。本文就高速激光切割机床数控系统各方面进行了研究分析,以此来满足我国对激光切割机床数控技术发展的要求。%With therapid economic development,China's industrial technology have improved.Nowadays the cutting technology also has great innovation improvement,new laser cutting, and it has become one of the hot thermal cutting technology,laser cutting technology compared with the traditional cutting technology has high precision,high efficiency,low pollution.In order to meet the requirements of laser cutting equipment,such as digital precision,realizing this technology in china. In this paper,the high speed laser cutting CNC system is analyzed, in order to meet the development of China's cutting CNC technology requirements for laser.

  1. 高速激光切割机床数控系统探究%Study on the numerical control system for laser cutting machine

    Institute of Scientific and Technical Information of China (English)

    潘冬

    2015-01-01

    随着经济的迅速发展,我国工业技术也有了较大的改善。现如今切割技术也有了很大的创新改进,新兴的激光切割,它目前已成为热切割技术发展的热点之一,激光切割技术相比较传统切割技术多了高精度、高效率、低污染等优点。为了满足激光切割装备的数字化、精密化等要求,实现此种技术的国产化。本文就高速激光切割机床数控系统各方面进行了研究分析,以此来满足我国对激光切割机床数控技术发展的要求。%With the rapid economic development,China's industrial technology have improved.Nowadays the cutting technology also has great innovation improvement,new laser cutting,and it has become one of the hot thermal cutting technology,laser cutting technology compared with the traditional cutting technology has high precision,high efficiency,low pollution.In order to meet the requirements of laser cutting equipment,such as digital precision,realizing this technology in china.In this paper,the high speed laser cutting CNC system is analyzed,in order to meet the development of China's cutting CNC technology requirements for laser.

  2. Simulating Turing machines on Maurer machines

    NARCIS (Netherlands)

    Bergstra, J.A.; Middelburg, C.A.

    2008-01-01

    In a previous paper, we used Maurer machines to model and analyse micro-architectures. In the current paper, we investigate the connections between Turing machines and Maurer machines with the purpose to gain an insight into computability issues relating to Maurer machines. We introduce ways to

  3. 基于激光三角法的石油螺纹在机检测分析%Analysis of Measuring Petroleum Thread on Machine Based on Laser Triangulation Principle

    Institute of Scientific and Technical Information of China (English)

    王可; 戴佳卉; 孙兴伟; 谢文龙

    2016-01-01

    In the past, petroleum pipe thread was mostly measured by thread gauge, which was inefficient and easily affected by human factors. A non-contact measuring method on machine was put forward to handle those problems. Based on laser triangulation principle, a high precision laser, which was installed in a way of specular reflection, was used for measuring internal and external taper thread, and then using sliding window self-adapting Lyite Criteria algorithm, removed the jump point from the measured data. After-wards, the thread tooth profile data was obtained through linear fitting by method of least square. Other parameters of the thread were calculated by the thread profile data, and measuring internal and external pipe thread on machine was achieved in this way. Compared with the previous one, this method has the advantage of high accuracy, high efficiency, less influenced by the human factors, and it made breakthrough in the measurement of internal thread by high precision laser.%以往石油管锥螺纹检测主要以螺纹规检测为主,针对其人工检测效率低、受人为因素影响大等弊端,提出了一种非接触在机螺纹检测方案。该方案基于激光三角法原理,通过镜面反射的安装方式将高精度激光测头用于检测内外管锥螺纹,将测得的数据利用滑动窗体自适的莱以特准则剔除跳跃点,再利用最小二乘法将上述平滑处理后的数据线性拟合,得到螺纹牙廓形数据,通过牙廓形数据可以计算得到螺纹的各项参数,实现了内外管锥螺纹的在机检测过程。对比以往检测方式,该检测方式精度高、效率高、受人为因素影响小,并攻克了以往高精度激光测头难以深入内螺纹测量的技术瓶颈。

  4. Environmentally Friendly Machining

    CERN Document Server

    Dixit, U S; Davim, J Paulo

    2012-01-01

    Environment-Friendly Machining provides an in-depth overview of environmentally-friendly machining processes, covering numerous different types of machining in order to identify which practice is the most environmentally sustainable. The book discusses three systems at length: machining with minimal cutting fluid, air-cooled machining and dry machining. Also covered is a way to conserve energy during machining processes, along with useful data and detailed descriptions for developing and utilizing the most efficient modern machining tools. Researchers and engineers looking for sustainable machining solutions will find Environment-Friendly Machining to be a useful volume.

  5. Application of Laser Positioning Device to C Arm X-ray Machine in Operating Room%激光准直定位装置应用于手术室C型臂X线机的研究

    Institute of Scientific and Technical Information of China (English)

    王晓民; 杨蕾; 贾汉泉; 刘延梅

    2012-01-01

    Objective To design a laser positioning device so as to apply on C arm X-ray machine of SIEMENS ARCADIS Varic in the operating room. Methods Several design schemes had been compared. The optimal design was then determined and made. Positioning line cross was formed on the plane paralleled to the image enhancement board using two semiconductor lasers supplied by three NO.5 batteries, so precise orientation of laser spot center was realized. The batteries were put in a switch box fixed on the chassis. The electric wire was held in place by aluminum plate, wire clip and hot-melt adhesive. Lasers matched the oblique outer edge of C arm X-ray machine perfectly. Results The maximal distance between the positioning tine cross and the image enhancement board was 80 centimeters. The technical indicators, such as security, positioning accuracy and handiness. had been realized. And the clinical diagnosis demands had been met. Conclusion The device is cost-effective and reliable. The X-ray irradiation time can be reduced, and the accumulated radiation dose of patients and doctors can also be reduced. The device can he applied to other C arm X-ray machines in this way.[Chinese Medical Equipment Journal,2012,33(5):32-34]%目的:研制一款激光准直定位装置应用于手术室西门子ARCADIS Varic C型臂X线机.方法:通过比较几种不同设计方案的优、缺点,确定了最优设计方案,并完成了装置的制作.采用2个由3节5号电池供电的一字形半导体激光器,在平行于影像增强板的平面上形成十字形定位线,实现中心定位;电池置于开关控制盒内并固定在机架上;供电线采用铝塑板、线扎及热溶胶等固定;激光器部分与球管端的斜外缘塑料外壳相配合.结果:此装置所形成的十字定位线距离影像增强板最高可达80 cm,定位准确、操作方便,很好地满足了临床诊断的需要.结论:该激光准直定位装置大大减少了设备采购支出,有望缩短X线照

  6. Machine Transliteration

    CERN Document Server

    Knight, K; Knight, Kevin; Graehl, Jonathan

    1997-01-01

    It is challenging to translate names and technical terms across languages with different alphabets and sound inventories. These items are commonly transliterated, i.e., replaced with approximate phonetic equivalents. For example, "computer" in English comes out as "konpyuutaa" in Japanese. Translating such items from Japanese back to English is even more challenging, and of practical interest, as transliterated items make up the bulk of text phrases not found in bilingual dictionaries. We describe and evaluate a method for performing backwards transliterations by machine. This method uses a generative model, incorporating several distinct stages in the transliteration process.

  7. Key Technology Study of Laser Texturing Machine of Plastic Mould%塑料模具激光蚀纹机的关键技术研究

    Institute of Scientific and Technical Information of China (English)

    周泳全; 吴忆锋; 赵盛宇; 肖永山; 周逸

    2011-01-01

    在塑料模具蚀纹加工中,传统的化学蚀刻方法存在污染大、加工周期长的缺点.基于最新的3D动态振镜扫描技术,对模具激光蚀刻原理进行了分析和探讨;对模具激光蚀刻工艺参数进行了优化;并设计了塑料产品常见的蚀纹图案.经过对模具激光蚀纹机的光学系统、机械系统、电气系统及软件系统等整体方案的设计及丁艺实验,证明模具激光蚀刻技术能满足了塑料模具加工企业的蚀纹和环保节能需求,同时为激光加工技术在塑料模具行业的广泛应用奠定基础.%Traditional chemical texturing method caused serious pollution and long process time in plastic mould texturing process. Based on the newest 3D dynamic vibrating mirror scan technology, the principle of laser-texturing of mould was analyzed and studied. The laser texturing parameter had been optimized, and the common texture figure of plastic product was designed. The design and process experiments of optic system, mechanical system, electrical system as well as software system proved that laser-texturing technology could met the need of plastic mould processing companies for mould texture and anti-pollution, and pushed the application of laser technology in plastic mould industry as well.

  8. Machine Protection

    CERN Document Server

    Schmidt, R

    2014-01-01

    The protection of accelerator equipment is as old as accelerator technology and was for many years related to high-power equipment. Examples are the protection of powering equipment from overheating (magnets, power converters, high-current cables), of superconducting magnets from damage after a quench and of klystrons. The protection of equipment from beam accidents is more recent. It is related to the increasing beam power of high-power proton accelerators such as ISIS, SNS, ESS and the PSI cyclotron, to the emission of synchrotron light by electron–positron accelerators and FELs, and to the increase of energy stored in the beam (in particular for hadron colliders such as LHC). Designing a machine protection system requires an excellent understanding of accelerator physics and operation to anticipate possible failures that could lead to damage. Machine protection includes beam and equipment monitoring, a system to safely stop beam operation (e.g. dumping the beam or stopping the beam at low energy) and an ...

  9. Non-equilibrium quantum heat machines

    Science.gov (United States)

    Alicki, Robert; Gelbwaser-Klimovsky, David

    2015-11-01

    Standard heat machines (engine, heat pump, refrigerator) are composed of a system (working fluid) coupled to at least two equilibrium baths at different temperatures and periodically driven by an external device (piston or rotor) sometimes called the work reservoir. The aim of this paper is to go beyond this scheme by considering environments which are stationary but cannot be decomposed into a few baths at thermal equilibrium. Such situations are important, for example in solar cells, chemical machines in biology, various realizations of laser cooling or nanoscopic machines driven by laser radiation. We classify non-equilibrium baths depending on their thermodynamic behavior and show that the efficiency of heat machines powered by them is limited by the generalized Carnot bound.

  10. Laser Cutting of Different Materials

    Directory of Open Access Journals (Sweden)

    Kadir ÇAVDAR

    2013-08-01

    Full Text Available In this paper; in general potential developments and trends of a particular machining field by extensively evaluating present studies of laser beam machining have been discussed. As it is indicated below, technical literatures have been subsumed under five major headlines: Experimental studies, reviews, optimization researches of the cutting parameters, theoretical modelling studies of laser beam cutting and academic studies relating to laser cutting

  11. High Metal Removal Rate Process for Machining Difficult Materials

    Energy Technology Data Exchange (ETDEWEB)

    Bates, Robert; McConnell, Elizabeth

    2016-06-29

    Machining methods across many industries generally require multiple operations to machine and process advanced materials, features with micron precision, and complex shapes. The resulting multiple machining platforms can significantly affect manufacturing cycle time and the precision of the final parts, with a resultant increase in cost and energy consumption. Ultrafast lasers represent a transformative and disruptive technology that removes material with micron precision and in a single step manufacturing process. Such precision results from athermal ablation without modification or damage to the remaining material which is the key differentiator between ultrafast laser technologies and traditional laser technologies or mechanical processes. Athermal ablation without modification or damage to the material eliminates post-processing or multiple manufacturing steps. Combined with the appropriate technology to control the motion of the work piece, ultrafast lasers are excellent candidates to provide breakthrough machining capability for difficult-to-machine materials. At the project onset in early 2012, the project team recognized that substantial effort was necessary to improve the application of ultrafast laser and precise motion control technologies (for micromachining difficult-to-machine materials) to further the aggregate throughput and yield improvements over conventional machining methods. The project described in this report advanced these leading-edge technologies thru the development and verification of two platforms: a hybrid enhanced laser chassis and a multi-application testbed.

  12. Laser-diode pumped Nd:YAG lasers; Laser diode reiki Nd:YAG lasear

    Energy Technology Data Exchange (ETDEWEB)

    Yuasa, H.; Akiyama, Y.; Nakayama, M. [Toshiba Corp., Tokyo (Japan)

    2000-04-01

    Laser-diode pumped Nd:YAG lasers are expected to be applied to laser processing fields such as welding, cutting, drilling, and marking due to their potential for high efficiency and compactness. We are designing and developing laser-diode pumped Nd:YAG lasers using numerical analysis simulation techniques such as ray tracing and thermal analysis. We have succeeded in achieving a laser power of more than 3 kW with 20% efficiency, which is the best ever obtained. In addition, we have developed a laser-diode pumped green laser by second harmonic generation, for precision machining on silicon wafers. (author)

  13. Automation of printing machine

    OpenAIRE

    Sušil, David

    2016-01-01

    Bachelor thesis is focused on the automation of the printing machine and comparing the two types of printing machines. The first chapter deals with the history of printing, typesettings, printing techniques and various kinds of bookbinding. The second chapter describes the difference between sheet-fed printing machines and offset printing machines, the difference between two representatives of rotary machines, technological process of the products on these machines, the description of the mac...

  14. Qualification and standardisation of solid phase surface machining using laser beams. Final report; Qualifizierung und Normung der Festphasen-Oberflaechenbearbeitung mit Laserstrahlung. Abschlussbericht

    Energy Technology Data Exchange (ETDEWEB)

    Bergmann, H.W.; Mueller, K.

    1999-07-01

    Laser hardening is still not generally accepted, owing to a lack of data on material response, which makes it hard for the potential user to assess the possibilities and limits of the process. A test method was developed and tested on four model materials. The results will provide a basis for an extensive dta compilation and will be developed into future specifications for application of laser hardening. The investigations described here are not laser-specific and can be applied to other surface hardening processes as well. [German] Das Laserstrahlhaerten hat trotz intensiver Forschung und Entwicklung noch nicht die erwartete Verbreitung in der Industrie gefunden. Daher ist es das Ziel der vorliegenden Arbeit, das Verfahren aus werkstoffkundlicher Sicht zu qualifizieren, um damit eine wichtige Voraussetzung fuer die breite industrielle Nutzung zu schaffen. Als wesentliche Hindernisse wurde der fehlende Haertbarkeitsbegriff und ein Mangel an Daten zur Beschreibung des Werkstoffverhaltens erkannt. Dies macht es einem potentiellen Anwender schwer, die Moeglichkeiten und Grenzen des Verfahrens abzuschaetzen. Fuer die Charakterisierung des Werkstoffverhaltens bei einer Kurzzeitaustenitisierung war es notwendig, bestehende Pruefverfahren zu modifizieren, um den Gegebenheiten einer raschen Erwaermung Rechnung zu tragen. Es wurde ein einfacher Versuchsstand entwickelt, der es erlaubt, die generelle Eignung eines Werkstoffs zu beurteilen. Die Anwendung des Pruefverfahrens auf vier verschiedene Modellwerkstoffe hat dessen Aussagefaehigkeit bestaetigt. Die konduktive Erwaermung von Proben ermoeglicht es, die Zeit-Temperaturzyklen, die beim Laserstrahlhaerten auftreten, naeherungsweise nachzubilden. Damit laesst sich einerseits das Umwandlungsverhalten der Werkstoffe auf elegante Art und Weise untersuchen, andererseits ist es moeglich, die mechanischen Eigenschaften in dem Zustand zu messen, den der Werkstoff im Augenblick der Laserbehandlung tatsaechlich besitzt. Diese

  15. Machine musicianship

    Science.gov (United States)

    Rowe, Robert

    2002-05-01

    The training of musicians begins by teaching basic musical concepts, a collection of knowledge commonly known as musicianship. Computer programs designed to implement musical skills (e.g., to make sense of what they hear, perform music expressively, or compose convincing pieces) can similarly benefit from access to a fundamental level of musicianship. Recent research in music cognition, artificial intelligence, and music theory has produced a repertoire of techniques that can make the behavior of computer programs more musical. Many of these were presented in a recently published book/CD-ROM entitled Machine Musicianship. For use in interactive music systems, we are interested in those which are fast enough to run in real time and that need only make reference to the material as it appears in sequence. This talk will review several applications that are able to identify the tonal center of musical material during performance. Beyond this specific task, the design of real-time algorithmic listening through the concurrent operation of several connected analyzers is examined. The presentation includes discussion of a library of C++ objects that can be combined to perform interactive listening and a demonstration of their capability.

  16. Analysis on the Testing Accuracy of Machine Tool Precision Based on Laser Interferometer%基于激光干涉仪机床位置精度检测准确性的分析

    Institute of Scientific and Technical Information of China (English)

    李志宏; 吴清锋; 曾爱平; 成绵龙

    2015-01-01

    利用激光干涉仪对一台立式加工中心进行位置精度检测, 通过改变试验参数获取一系列试验数据. 分析结果表明: 机床丝杆副的热稳定状态、 检测元件的热膨胀系数、 测量设备的传感器放置位置等对位置精度检测的准确性均有显著影响.%Using a laser interferometer, the accuracy test of a vertical machining center was carried out to obtain a series of exper-imental data by changing different parameters. The results show that the thermal stability of lead-screw pair, the thermal expansion coef-ficient of testing element and the location of sensor etc have significant effect on testing accuracy of position precision.

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

    Energy Technology Data Exchange (ETDEWEB)

    Bian, Hao; Yang, Qing; Chen, Feng, E-mail: chenfeng@mail.xjtu.edu.cn; Liu, Hewei; Du, Guangqing; Deng, Zefang; Si, Jinhai; Yun, Feng; Hou, Xun

    2013-07-01

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

  18. Study of Phospholipids in Single Cells Using an Integrated Microfluidic Device Combined with Matrix-Assisted Laser Desorption/Ionization Mass Spectrometry.

    Science.gov (United States)

    Xie, Weiyi; Gao, Dan; Jin, Feng; Jiang, Yuyang; Liu, Hongxia

    2015-07-21

    Single-cell trapping and high-throughput mass spectrometry analysis remain challenging now. Current technologies for single-cell analysis have several limitations, such as throughput, space resolution, and multicomponent analysis. In this study, we demonstrate, for the first time, the combination of microfluidic chip and matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS) for high-throughput and automatic single-cell phospholipids analysis. A microwell-array-based microfluidic chip was designed and fabricated for cell array formation on an indium tin oxide (ITO)-coated glass slide. Mass spectrometry imaging measurement with 25 μm pixel size was performed with a MALDI ion source. Eight phospholipids in a single A549 cell were detected, and their structures were further identified by MS/MS spectra. Selected ion images were generated with a bin width of Δm/z ± 0.005. The selected ion images and optical images of the cell array showed excellent correlation, and mass spectrometry information on phospholipids from 1-3 cells was extracted automatically by selecting pixels with the same fixed interval between microwells on the chip. The measurement and data extraction could be processed in several minutes to achieve a high-throughput analysis. Through the optimization of different microwell sizes and different matrices, this method showed potential for the analysis of other metabolites or metabolic changes at the single-cell level.

  19. Laser cutting plastic materials

    Energy Technology Data Exchange (ETDEWEB)

    Van Cleave, R.A.

    1980-08-01

    A 1000-watt CO/sub 2/ laser has been demonstrated as a reliable production machine tool for cutting of plastics, high strength reinforced composites, and other nonmetals. More than 40 different plastics have been laser cut, and the results are tabulated. Applications for laser cutting described include fiberglass-reinforced laminates, Kevlar/epoxy composites, fiberglass-reinforced phenolics, nylon/epoxy laminates, ceramics, and disposable tooling made from acrylic.

  20. Electrical machines mathematical fundamentals of machine topologies

    CERN Document Server

    Gerling, Dieter

    2015-01-01

    Electrical Machines and Drives play a powerful role in industry with an ever increasing importance. This fact requires the understanding of machine and drive principles by engineers of many different disciplines. Therefore, this book is intended to give a comprehensive deduction of these principles. Special attention is given to the precise mathematical derivation of the necessary formulae to calculate machines and drives and to the discussion of simplifications (if applied) with the associated limits. The book shows how the different machine topologies can be deduced from general fundamentals, and how they are linked together. This book addresses graduate students, researchers, and developers of Electrical Machines and Drives, who are interested in getting knowledge about the principles of machine and drive operation and in detecting the mathematical and engineering specialties of the different machine and drive topologies together with their mutual links. The detailed - but nevertheless compact - mat...

  1. The deleuzian abstract machines

    DEFF Research Database (Denmark)

    Werner Petersen, Erik

    2005-01-01

    production. In Kafka: Toward a Minor Literature, Deleuze and Guatari gave the most comprehensive explanation to the abstract machine in the work of art. Like the war-machines of Virilio, the Kafka-machine operates in three gears or speeds. Furthermore, the machine is connected to spatial diagrams...

  2. Comparative investigation of partial least squares discriminant analysis and support vector machines for geological cuttings identification using laser-induced breakdown spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Tian, Ye; Wang, Zhennan [Optics and Optoelectronics Laboratory, Ocean University of China, Qingdao, Shandong 266100 (China); Han, Xiaoshuang [Optics and Optoelectronics Laboratory, Ocean University of China, Qingdao, Shandong 266100 (China); College of Electronic Information Engineering, Inner Mongolia University, Hohhot, Inner Mongolia 010021 (China); Hou, Huaming [Optics and Optoelectronics Laboratory, Ocean University of China, Qingdao, Shandong 266100 (China); Zheng, Ronger, E-mail: rzheng@ouc.edu.cn [Optics and Optoelectronics Laboratory, Ocean University of China, Qingdao, Shandong 266100 (China)

    2014-12-01

    With the hope of applying laser-induced breakdown spectroscopy (LIBS) to the geological logging field, a series of cutting samples were classified using LIBS coupled with chemometric methods. In this paper, we focused on a comparative investigation of the linear PLS-DA method and non-linear SVM method. Both the optimal PLS-DA model and SVM model were built by the leave-one-out cross-validation (LOOCV) approach with the calibration LIBS spectra, and then tested by validation spectra. We show that the performance of SVM is significantly better than PLS-DA because of its ability to address the non-linear relationships in LIBS spectra, with a correct classification rate of 91.67% instead of 68.34%, and an unclassification rate of 3.33% instead of 28.33%. To further improve the classification accuracy, we then designed a new classification approach by the joint analysis of PLS-DA and SVM models. With this method, 95% of the validation spectra are correctly classified and no unclassified spectra are observed. This work demonstrated that the coupling of LIBS with the non-linear SVM method has great potential to be used for on-line classification of geological cutting samples, and the combination of PLS-DA and SVM enables the cuttings identification with an excellent performance. - Highlights: • The geological cuttings were classified using LIBS coupled with chemometric methods. • The non-linear SVM showed significantly better performance than PLS-DA. • The joint analysis of PLS-DA and SVMs provided an excellent accuracy of 95%.

  3. Simulation of Temperature Field for Si3 N4 Ceramics during Laser Assisted Micro-detonation Machining with Striking Arc%Si3N4陶瓷激光加热辅助引弧微爆炸加工温度场仿真

    Institute of Scientific and Technical Information of China (English)

    田欣利; 李富强; 王朋晓; 王龙; 唐修检

    2013-01-01

    The paper introduced simply the technologies of laser assisted micro-detonation machi-ning with striking arc and established its theoretical model of temperature field.Based on finite ele-ment theory,the temperature field of Si3 N4 ceramics during laser assisted micro-detonation machi-ning with striking arc was simulated with the aid of finite element analysis software.Furthermore, the influence of process parameters on temperature distribution was studied.The simulation results show the highest temperature is enhanced from 12 600℃ to 14 381℃ only with micro-detonation machining with striking arc.The temperature increases with increment of the laser power and decrea-ses with growth of the size of light spot.With the increase of distance between the laser heating point and processing position,the temperature rises firstly and then drops.The effect of feeding speed on temperature is not so outstanding.The simulation results is reliable and can provide theory evidences for uncovering the machining mechanism of laser assisted micro-detonation machining with striking arc and choosing proper process parameters.%介绍了激光加热辅助引弧微爆炸加工技术,建立了温度场数学模型,使用有限元分析软件计算出了加工Si3 N4陶瓷时的温度场分布,并研究了工艺参数对温度场的影响。仿真结果表明:用激光加热辅助引弧微爆炸加工使加工温度得到提高,从单独使用引弧微爆炸加工的12600℃提高到14381℃;其最高温度随着激光功率的增大而升高,随光斑尺寸的增大而减小,随激光加热点距引弧微爆炸加工点距离的增大先增大后减小,随进给速度的增大而减小。研究结果为揭示激光加热辅助引弧微爆炸加工机理和选择合理工艺参数提供了理论依据。

  4. Laser Processing and Chemistry

    CERN Document Server

    Bäuerle, Dieter

    2011-01-01

    This book gives an overview of the fundamentals and applications of laser-matter interactions, in particular with regard to laser material processing. Special attention is given to laser-induced physical and chemical processes at gas-solid, liquid-solid, and solid-solid interfaces. Starting with the background physics, the book proceeds to examine applications of lasers in “standard” laser machining and laser chemical processing (LCP), including the patterning, coating, and modification of material surfaces. This fourth edition has been enlarged to cover the rapid advances in the understanding of the dynamics of materials under the action of ultrashort laser pulses, and to include a number of new topics, in particular the increasing importance of lasers in various different fields of surface functionalizations and nanotechnology. In two additional chapters, recent developments in biotechnology, medicine, art conservation and restoration are summarized. Graduate students, physicists, chemists, engineers, a...

  5. Time-lapse cinematography-compatible polystyrene-based microwell culture system: a novel tool for tracking the development of individual bovine embryos.

    Science.gov (United States)

    Sugimura, Satoshi; Akai, Tomonori; Somfai, Tamás; Hirayama, Muneyuki; Aikawa, Yoshio; Ohtake, Masaki; Hattori, Hideshi; Kobayashi, Shuji; Hashiyada, Yutaka; Konishi, Kazuyuki; Imai, Kei

    2010-12-01

    We have developed a polystyrene-based well-of-the-well (WOW) system using injection molding to track individual embryos throughout culture using time-lapse cinematography (TLC). WOW culture of bovine embryos following in vitro fertilization was compared with conventional droplet culture (control). No differences between control- and WOW-cultured embryos were observed during development to the blastocyst stage. Morphological quality and inner cell mass (ICM) and trophectoderm (TE) cell numbers were not different between control- and WOW-derived blastocysts; however, apoptosis in both the ICM and TE cells was reduced in WOW culture (P < 0.01). Oxygen consumption in WOW-derived blastocysts was closer to physiological level than that of control-derived blastocysts. Moreover, WOW culture improved embryo viability, as indicated by increased pregnancy rates at Days 30 and 60 after embryo transfer (P < 0.05). TLC monitoring was performed to evaluate the cleavage pattern and the duration of the first cell cycle of embryos from oocytes collected by ovum pickup; correlations with success of pregnancy were determined. Logistic regression analysis indicated that the cleavage pattern correlated with success of pregnancy (P < 0.05), but cell cycle length did not. Higher pregnancy rates (66.7%) were observed for animals in which transferred blastocysts had undergone normal cleavage, identified by the presence of two blastomeres of the same size without fragmentation, than among those with abnormal cleavage (33.3%). These results suggest that our microwell culture system is a powerful tool for producing and selecting healthy embryos and for identifying viability biomarkers.

  6. Charge-transfer reaction of 1,4-benzoquinone with crizotinib: spectrophotometric study, computational molecular modeling and use in development of microwell assay for crizotinib.

    Science.gov (United States)

    Darwish, Ibrahim A; Alshehri, Jamilah M; Alzoman, Nourah Z; Khalil, Nasr Y; Abdel-Rahman, Hamdy M

    2014-10-15

    The reaction of 1,4-benzoquinone (BQ) with crizotinib (CZT); a novel drug used for treatment of non-small cell lung cancer) was investigated in different solvents of varying dielectric constants and polarity indexes. The reaction resulted in the formation of a red-colored product. Spectrophotometric investigations confirmed that the reaction proceeded through charge-transfer (CT) complex formation. The molar absorptivity of the complex was found to be linearly correlated with the dielectric constant and polarity index of the solvent; the correlation coefficients were 0.9425 and 0.8340, respectively. The stoichiometric ratio of BQ:CZT was found to be 2:1 and the association constant of the complex was found to be 0.26×10(3)lmol(-1). The kinetics of the reaction was studied; the order of the reaction, rate and rate constant were determined. Computational molecular modeling for the complex between BQ and CZT was conducted, the sites of interaction on CZT molecule were determined, and the mechanism of the reaction was postulated. The reaction was employed as a basis in the development of a novel 96-microwell assay for CZT. The assay limits of detection and quantitation were 5.2 and 15.6μgml(-1), respectively. The assay was validated as per the guidelines of the International Conference on Harmonization (ICH) and successfully applied to the analysis of CZT in its bulk and capsules with good accuracy and precision. The assay has high throughput and consumes minimum volume of organic solvent thus it reduces the exposures of the analysts to the toxic effects of organic solvents, and significantly reduces the analysis cost. Copyright © 2014 Elsevier B.V. All rights reserved.

  7. Measuring the internal temp erature of dielectrics machined by the ultrashort laser pulse through the black-b o dy irradiation metho d%黑体辐射法测量电介质内部被超短激光脉冲加工后的温度∗

    Institute of Scientific and Technical Information of China (English)

    王承伟; 赵全忠; 钱静; 黄媛媛; 王关德; 李阳博; 柏锋; 范文中; 李虹瑾

    2016-01-01

    Black-body irradiation method can be utilized for measuring the instantaneous temperatures of electrons and lattice in dielectric machined by the ultrashort laser. One ultrashort laser pulse, of which the pulse energy and pulse duration are 240 µJ and 599 fs respectively, is focused into the fused silica by objective lenses with a magnification of 10 times. The focal point is at the position of 874 µm. The microstructure induced by laser near the focal point is 16 µm wide and 104 µm long. The central region of the microstructure is heavily damaged, and the marginal region is slightly modified. The black-body irradiation spectra are recorded by the system that is composed of objective lenses, a fiber with two lenses, a spectrometer and an intensified charge coupled device (ICCD). Furthermore, other imaging elements can also be used as alternative to objective lenses, for measuring black-body spectra. The image point, which is conjunctive with the machined region due to the imaging effect of the objective lenses, is coupled into the fiber by one lens. Another lens collimates the diverging light beam from the fiber. The collimated light is incident into the spectrometer and dispersed on the ICCD. Because the minimum gate width of ICCD is much larger than the coupled time of electron and lattice, the temperature of electron equals that of lattice when they are characterized by the black-body irradiation method. The temperatures of the electrons and the lattice are regarded as the temperature of dielectric. When the system acquires the reflection peak of incident ultrashort laser, the delay is set to be 0 ns, and the central wavelength of the peak is 784 nm. Therefore, to eliminate the reflection peak, the second harmonic and supercontinuum spectra, the delay for black-body irradiation acquirement is set to be above 6 ns and the machined region should be confined inside the dielectric. The system collects the black-body spectra emitted by the heat-affected zone in

  8. Integration of Machining and Measuring Processes Using On-Machine Measurement Technology

    Institute of Scientific and Technical Information of China (English)

    Myeong; Woo; Cho; Tae; Il; Seo; Dong; Sam; Park

    2002-01-01

    This paper presents an integration methodology for ma chining and measuring processes using OMM (On-Machine Measurement) technology b ased on CAD/CAM/CAI integration concept. OMM uses a CNC machining center as a me asuring station by changing the tools into measuring probes such as touch-type, laser and vision. Although the measurement accuracy is not good compared to tha t of the CMM (Coordinate Measuring Machine), there are distinctive advantages us ing OMM in real situation. In this paper, two topics a...

  9. Recent advances in micro- and nano-machining technologies

    Science.gov (United States)

    Gao, Shang; Huang, Han

    2016-12-01

    Device miniaturization is an emerging advanced technology in the 21st century. The miniaturization of devices in different fields requires production of micro- and nano-scale components. The features of these components range from the sub-micron to a few hundred microns with high tolerance to many engineering materials. These fields mainly include optics, electronics, medicine, bio-technology, communications, and avionics. This paper reviewed the recent advances in micro- and nano-machining technologies, including micro-cutting, micro-electrical-discharge machining, laser micro-machining, and focused ion beam machining. The four machining technologies were also compared in terms of machining efficiency, workpiece materials being machined, minimum feature size, maximum aspect ratio, and surface finish.

  10. Machine tool structures

    CERN Document Server

    Koenigsberger, F

    1970-01-01

    Machine Tool Structures, Volume 1 deals with fundamental theories and calculation methods for machine tool structures. Experimental investigations into stiffness are discussed, along with the application of the results to the design of machine tool structures. Topics covered range from static and dynamic stiffness to chatter in metal cutting, stability in machine tools, and deformations of machine tool structures. This volume is divided into three sections and opens with a discussion on stiffness specifications and the effect of stiffness on the behavior of the machine under forced vibration c

  11. High power lasers

    CERN Document Server

    Niku-Lari, A

    1989-01-01

    The use of lasers for the working and treatment of materials is becoming increasingly common in industry. However, certain laser applications, for example, in welding, cutting and drilling, are more widely exploited than others. Whilst the potential of lasers for the surface treatment of metals is well recognised, in practice, this particular application is a relative newcomer. The 24 papers in this volume present the latest research and engineering developments in the use of lasers for processes such as surface melting, surface alloying and cladding, and machining, as well as discussing th

  12. Design of Demining Machines

    CERN Document Server

    Mikulic, Dinko

    2013-01-01

    In constant effort to eliminate mine danger, international mine action community has been developing safety, efficiency and cost-effectiveness of clearance methods. Demining machines have become necessary when conducting humanitarian demining where the mechanization of demining provides greater safety and productivity. Design of Demining Machines describes the development and testing of modern demining machines in humanitarian demining.   Relevant data for design of demining machines are included to explain the machinery implemented and some innovative and inspiring development solutions. Development technologies, companies and projects are discussed to provide a comprehensive estimate of the effects of various design factors and to proper selection of optimal parameters for designing the demining machines.   Covering the dynamic processes occurring in machine assemblies and their components to a broader understanding of demining machine as a whole, Design of Demining Machines is primarily tailored as a tex...

  13. Applied machining technology

    CERN Document Server

    Tschätsch, Heinz

    2010-01-01

    Machining and cutting technologies are still crucial for many manufacturing processes. This reference presents all important machining processes in a comprehensive and coherent way. It includes many examples of concrete calculations, problems and solutions.

  14. Machining with abrasives

    CERN Document Server

    Jackson, Mark J

    2011-01-01

    Abrasive machining is key to obtaining the desired geometry and surface quality in manufacturing. This book discusses the fundamentals and advances in the abrasive machining processes. It provides a complete overview of developing areas in the field.

  15. Women, Men, and Machines.

    Science.gov (United States)

    Form, William; McMillen, David Byron

    1983-01-01

    Data from the first national study of technological change show that proportionately more women than men operate machines, are more exposed to machines that have alienating effects, and suffer more from the negative effects of technological change. (Author/SSH)

  16. Machine medical ethics

    CERN Document Server

    Pontier, Matthijs

    2015-01-01

    The essays in this book, written by researchers from both humanities and sciences, describe various theoretical and experimental approaches to adding medical ethics to a machine in medical settings. Medical machines are in close proximity with human beings, and getting closer: with patients who are in vulnerable states of health, who have disabilities of various kinds, with the very young or very old, and with medical professionals. In such contexts, machines are undertaking important medical tasks that require emotional sensitivity, knowledge of medical codes, human dignity, and privacy. As machine technology advances, ethical concerns become more urgent: should medical machines be programmed to follow a code of medical ethics? What theory or theories should constrain medical machine conduct? What design features are required? Should machines share responsibility with humans for the ethical consequences of medical actions? How ought clinical relationships involving machines to be modeled? Is a capacity for e...

  17. Brain versus Machine Control.

    Directory of Open Access Journals (Sweden)

    Jose M Carmena

    2004-12-01

    Full Text Available Dr. Octopus, the villain of the movie "Spiderman 2", is a fusion of man and machine. Neuroscientist Jose Carmena examines the facts behind this fictional account of a brain- machine interface

  18. Meso-scale machining capabilities and issues

    Energy Technology Data Exchange (ETDEWEB)

    BENAVIDES,GILBERT L.; ADAMS,DAVID P.; YANG,PIN

    2000-05-15

    Meso-scale manufacturing processes are bridging the gap between silicon-based MEMS processes and conventional miniature machining. These processes can fabricate two and three-dimensional parts having micron size features in traditional materials such as stainless steels, rare earth magnets, ceramics, and glass. Meso-scale processes that are currently available include, focused ion beam sputtering, micro-milling, micro-turning, excimer laser ablation, femto-second laser ablation, and micro electro discharge machining. These meso-scale processes employ subtractive machining technologies (i.e., material removal), unlike LIGA, which is an additive meso-scale process. Meso-scale processes have different material capabilities and machining performance specifications. Machining performance specifications of interest include minimum feature size, feature tolerance, feature location accuracy, surface finish, and material removal rate. Sandia National Laboratories is developing meso-scale electro-mechanical components, which require meso-scale parts that move relative to one another. The meso-scale parts fabricated by subtractive meso-scale manufacturing processes have unique tribology issues because of the variety of materials and the surface conditions produced by the different meso-scale manufacturing processes.

  19. A novel 96-microwell-based high-throughput spectrophotometric assay for pharmaceutical quality control of crizotinib, a novel potent drug for the treatment of non-small cell lung cancer

    Directory of Open Access Journals (Sweden)

    Tanveer Ahmed Wani

    2015-06-01

    Full Text Available This study describes the development and validation of a novel 96-microwell-based high throughput spectrophotometric assay for pharmaceutical quality control of crizotinib (CZT, a novel drug for the treatment of non-small cell lung cancer. We examined the reaction between CZT and 1,2-naphthoquinone-4-sulphonate, a chromogenic reagent. A red-colored product showing a maximum absorption peak (λmax at 490 nm was produced in an alkaline medium (pH 9. We examined stoichiometry of the reaction and postulated the reaction mechanism. To our knowledge, this is the first study to describe a color-developing reaction for the proposed assay. The reaction was performed in a 96-microwell plate, and the absorbance of the colored product was measured using an absorbance reader at 490 nm. Under optimized reaction conditions, Beer's law, which shows a correlation between absorbance and CZT concentration, was obeyed in the range of 4-50 µg/well with an appropriate correlation coefficient (0.999. The limits of detection and quantification were 1.73 and 5.23 µg/well, respectively. The assay showed high precision and accuracy. The proposed assay was applied successfully for the determination of CZT in capsules. Thus, the assay proposed in this study is practical and valuable for routine application in pharmaceutical quality control laboratories.

  20. A Universal Reactive Machine

    DEFF Research Database (Denmark)

    Andersen, Henrik Reif; Mørk, Simon; Sørensen, Morten U.

    1997-01-01

    Turing showed the existence of a model universal for the set of Turing machines in the sense that given an encoding of any Turing machine asinput the universal Turing machine simulates it. We introduce the concept of universality for reactive systems and construct a CCS processuniversal...

  1. Asynchronized synchronous machines

    CERN Document Server

    Botvinnik, M M

    1964-01-01

    Asynchronized Synchronous Machines focuses on the theoretical research on asynchronized synchronous (AS) machines, which are "hybrids” of synchronous and induction machines that can operate with slip. Topics covered in this book include the initial equations; vector diagram of an AS machine; regulation in cases of deviation from the law of full compensation; parameters of the excitation system; and schematic diagram of an excitation regulator. The possible applications of AS machines and its calculations in certain cases are also discussed. This publication is beneficial for students and indiv

  2. Quantum machine learning.

    Science.gov (United States)

    Biamonte, Jacob; Wittek, Peter; Pancotti, Nicola; Rebentrost, Patrick; Wiebe, Nathan; Lloyd, Seth

    2017-09-13

    Fuelled by increasing computer power and algorithmic advances, machine learning techniques have become powerful tools for finding patterns in data. Quantum systems produce atypical patterns that classical systems are thought not to produce efficiently, so it is reasonable to postulate that quantum computers may outperform classical computers on machine learning tasks. The field of quantum machine learning explores how to devise and implement quantum software that could enable machine learning that is faster than that of classical computers. Recent work has produced quantum algorithms that could act as the building blocks of machine learning programs, but the hardware and software challenges are still considerable.

  3. Precision machine design

    CERN Document Server

    Slocum, Alexander H

    1992-01-01

    This book is a comprehensive engineering exploration of all the aspects of precision machine design - both component and system design considerations for precision machines. It addresses both theoretical analysis and practical implementation providing many real-world design case studies as well as numerous examples of existing components and their characteristics. Fast becoming a classic, this book includes examples of analysis techniques, along with the philosophy of the solution method. It explores the physics of errors in machines and how such knowledge can be used to build an error budget for a machine, how error budgets can be used to design more accurate machines.

  4. Self-Calibrating Surface Measuring Machine

    Science.gov (United States)

    Greenleaf, Allen H.

    1983-04-01

    A new kind of surface-measuring machine has been developed under government contract at Itek Optical Systems, a Division of Itek Corporation, to assist in the fabrication of large, highly aspheric optical elements. The machine uses four steerable distance-measuring interferometers at the corners of a tetrahedron to measure the positions of a retroreflective target placed at various locations against the surface being measured. Using four interferometers gives redundant information so that, from a set of measurement data, the dimensions of the machine as well as the coordinates of the measurement points can be determined. The machine is, therefore, self-calibrating and does not require a structure made to high accuracy. A wood-structured prototype of this machine was made whose key components are a simple form of air bearing steering mirror, a wide-angle cat's eye retroreflector used as the movable target, and tracking sensors and servos to provide automatic tracking of the cat's eye by the four laser beams. The data are taken and analyzed by computer. The output is given in terms of error relative to an equation of the desired surface. In tests of this machine, measurements of a 0.7 m diameter mirror blank have been made with an accuracy on the order of 0.2µm rms.

  5. Three-Dimensional Photochemical Machining with Lasers

    Science.gov (United States)

    1983-11-30

    mole) (nm) cT-T Biological Interest Compounds (Cont.) All trans- Lycopene 21.90 62.61 456.62 39000 I 20.50 58.61 487.80 152000 0 19.25 55.04 519.48...390000 19.00 54.32 526.32 258000 18.00 51.46 555.56 78000 Cis/trans- Lycopene 19.20 54.89 520.83 Retinene 22.22 63.53 450.05 75800 S Pheophytin;a 30.00...chloride was recrystallized from chlo- roform; the inhibitor (65 ppm methoxyhydroquinone) was removed from methylmethacrylate by base extraction and the

  6. Perspex machine: VII. The universal perspex machine

    Science.gov (United States)

    Anderson, James A. D. W.

    2006-01-01

    The perspex machine arose from the unification of projective geometry with the Turing machine. It uses a total arithmetic, called transreal arithmetic, that contains real arithmetic and allows division by zero. Transreal arithmetic is redefined here. The new arithmetic has both a positive and a negative infinity which lie at the extremes of the number line, and a number nullity that lies off the number line. We prove that nullity, 0/0, is a number. Hence a number may have one of four signs: negative, zero, positive, or nullity. It is, therefore, impossible to encode the sign of a number in one bit, as floating-point arithmetic attempts to do, resulting in the difficulty of having both positive and negative zeros and NaNs. Transrational arithmetic is consistent with Cantor arithmetic. In an extension to real arithmetic, the product of zero, an infinity, or nullity with its reciprocal is nullity, not unity. This avoids the usual contradictions that follow from allowing division by zero. Transreal arithmetic has a fixed algebraic structure and does not admit options as IEEE, floating-point arithmetic does. Most significantly, nullity has a simple semantics that is related to zero. Zero means "no value" and nullity means "no information." We argue that nullity is as useful to a manufactured computer as zero is to a human computer. The perspex machine is intended to offer one solution to the mind-body problem by showing how the computable aspects of mind and, perhaps, the whole of mind relates to the geometrical aspects of body and, perhaps, the whole of body. We review some of Turing's writings and show that he held the view that his machine has spatial properties. In particular, that it has the property of being a 7D lattice of compact spaces. Thus, we read Turing as believing that his machine relates computation to geometrical bodies. We simplify the perspex machine by substituting an augmented Euclidean geometry for projective geometry. This leads to a general

  7. Laser Marked Codes For Paperless Tracking Applications

    Science.gov (United States)

    Crater, David

    1987-01-01

    The application of laser markers for marking machine readable codes is described. Use of such codes for automatic tracking and considerations for marker performance and features are discussed. Available laser marker types are reviewed. Compatibility of laser/material combinations and material/code/reader systems are reviewed.

  8. Machining, joining and modifications of advanced materials

    CERN Document Server

    Altenbach, Holm

    2016-01-01

    This book presents the latest advances in mechanical and materials engineering applied to the machining, joining and modification of modern engineering materials. The contributions cover the classical fields of casting, forming and injection moulding as representative manufacturing methods, whereas additive manufacturing methods (rapid prototyping and laser sintering) are treated as more innovative and recent technologies that are paving the way for the manufacturing of shapes and features that traditional methods are unable to deliver. The book also explores water jet cutting as an innovative cutting technology that avoids the heat build-up typical of classical mechanical cutting. It introduces readers to laser cutting as an alternative technology for the separation of materials, and to classical bonding and friction stir welding approaches in the context of joining technologies. In many cases, forming and machining technologies require additional post-treatment to achieve the required level of surface quali...

  9. Machinability of advanced materials

    CERN Document Server

    Davim, J Paulo

    2014-01-01

    Machinability of Advanced Materials addresses the level of difficulty involved in machining a material, or multiple materials, with the appropriate tooling and cutting parameters.  A variety of factors determine a material's machinability, including tool life rate, cutting forces and power consumption, surface integrity, limiting rate of metal removal, and chip shape. These topics, among others, and multiple examples comprise this research resource for engineering students, academics, and practitioners.

  10. Pattern recognition & machine learning

    CERN Document Server

    Anzai, Y

    1992-01-01

    This is the first text to provide a unified and self-contained introduction to visual pattern recognition and machine learning. It is useful as a general introduction to artifical intelligence and knowledge engineering, and no previous knowledge of pattern recognition or machine learning is necessary. Basic for various pattern recognition and machine learning methods. Translated from Japanese, the book also features chapter exercises, keywords, and summaries.

  11. Support vector machines applications

    CERN Document Server

    Guo, Guodong

    2014-01-01

    Support vector machines (SVM) have both a solid mathematical background and good performance in practical applications. This book focuses on the recent advances and applications of the SVM in different areas, such as image processing, medical practice, computer vision, pattern recognition, machine learning, applied statistics, business intelligence, and artificial intelligence. The aim of this book is to create a comprehensive source on support vector machine applications, especially some recent advances.

  12. Machining of titanium alloys

    CERN Document Server

    2014-01-01

    This book presents a collection of examples illustrating the resent research advances in the machining of titanium alloys. These materials have excellent strength and fracture toughness as well as low density and good corrosion resistance; however, machinability is still poor due to their low thermal conductivity and high chemical reactivity with cutting tool materials. This book presents solutions to enhance machinability in titanium-based alloys and serves as a useful reference to professionals and researchers in aerospace, automotive and biomedical fields.

  13. Rotating electrical machines

    CERN Document Server

    Le Doeuff, René

    2013-01-01

    In this book a general matrix-based approach to modeling electrical machines is promulgated. The model uses instantaneous quantities for key variables and enables the user to easily take into account associations between rotating machines and static converters (such as in variable speed drives).   General equations of electromechanical energy conversion are established early in the treatment of the topic and then applied to synchronous, induction and DC machines. The primary characteristics of these machines are established for steady state behavior as well as for variable speed scenarios. I

  14. Chaotic Boltzmann machines.

    Science.gov (United States)

    Suzuki, Hideyuki; Imura, Jun-ichi; Horio, Yoshihiko; Aihara, Kazuyuki

    2013-01-01

    The chaotic Boltzmann machine proposed in this paper is a chaotic pseudo-billiard system that works as a Boltzmann machine. Chaotic Boltzmann machines are shown numerically to have computing abilities comparable to conventional (stochastic) Boltzmann machines. Since no randomness is required, efficient hardware implementation is expected. Moreover, the ferromagnetic phase transition of the Ising model is shown to be characterised by the largest Lyapunov exponent of the proposed system. In general, a method to relate probabilistic models to nonlinear dynamics by derandomising Gibbs sampling is presented.

  15. Tribology in machine design

    CERN Document Server

    Stolarski, Tadeusz

    1999-01-01

    ""Tribology in Machine Design is strongly recommended for machine designers, and engineers and scientists interested in tribology. It should be in the engineering library of companies producing mechanical equipment.""Applied Mechanics ReviewTribology in Machine Design explains the role of tribology in the design of machine elements. It shows how algorithms developed from the basic principles of tribology can be used in a range of practical applications within mechanical devices and systems.The computer offers today's designer the possibility of greater stringen

  16. Debugging the virtual machine

    Energy Technology Data Exchange (ETDEWEB)

    Miller, P.; Pizzi, R.

    1994-09-02

    A computer program is really nothing more than a virtual machine built to perform a task. The program`s source code expresses abstract constructs using low level language features. When a virtual machine breaks, it can be very difficult to debug because typical debuggers provide only low level machine implementation in formation to the software engineer. We believe that the debugging task can be simplified by introducing aspects of the abstract design into the source code. We introduce OODIE, an object-oriented language extension that allows programmers to specify a virtual debugging environment which includes the design and abstract data types of the virtual machine.

  17. Electrical machines & drives

    CERN Document Server

    Hammond, P

    1985-01-01

    Containing approximately 200 problems (100 worked), the text covers a wide range of topics concerning electrical machines, placing particular emphasis upon electrical-machine drive applications. The theory is concisely reviewed and focuses on features common to all machine types. The problems are arranged in order of increasing levels of complexity and discussions of the solutions are included where appropriate to illustrate the engineering implications. This second edition includes an important new chapter on mathematical and computer simulation of machine systems and revised discussions o

  18. Machine learning with R

    CERN Document Server

    Lantz, Brett

    2013-01-01

    Written as a tutorial to explore and understand the power of R for machine learning. This practical guide that covers all of the need to know topics in a very systematic way. For each machine learning approach, each step in the process is detailed, from preparing the data for analysis to evaluating the results. These steps will build the knowledge you need to apply them to your own data science tasks.Intended for those who want to learn how to use R's machine learning capabilities and gain insight from your data. Perhaps you already know a bit about machine learning, but have never used R; or

  19. Induction machine handbook

    CERN Document Server

    Boldea, Ion

    2002-01-01

    Often called the workhorse of industry, the advent of power electronics and advances in digital control are transforming the induction motor into the racehorse of industrial motion control. Now, the classic texts on induction machines are nearly three decades old, while more recent books on electric motors lack the necessary depth and detail on induction machines.The Induction Machine Handbook fills industry's long-standing need for a comprehensive treatise embracing the many intricate facets of induction machine analysis and design. Moving gradually from simple to complex and from standard to

  20. Femto- and pico second laser micro-nano processing for patterning surfaces by removal and deposition of materials

    NARCIS (Netherlands)

    Huis in 't veld, A.J.

    2011-01-01

    Ultra short laser pulses in the femto and pico second regime are the most important driver of new laser processes. 3D - Laser micro machining in a direct write mode is already available on an industrial scale whereas in the coming years laser nano machining will be further developed. The key for pro

  1. Femto- and pico second laser micro-nano processing for patterning surfaces by removal and deposition of materials

    NARCIS (Netherlands)

    Huis in 't veld, A.J.

    2011-01-01

    Ultra short laser pulses in the femto and pico second regime are the most important driver of new laser processes. 3D - Laser micro machining in a direct write mode is already available on an industrial scale whereas in the coming years laser nano machining will be further developed. The key for

  2. Virtual machine vs Real Machine: Security Systems

    Directory of Open Access Journals (Sweden)

    Dr. C. Suresh Gnana Das

    2009-08-01

    Full Text Available This paper argues that the operating system and applications currently running on a real machine should relocate into a virtual machine. This structure enables services to be added below the operating system and to do so without trusting or modifying the operating system or applications. To demonstrate the usefulness of this structure, we describe three services that take advantage of it: secure logging, intrusion prevention and detection, and environment migration. In particular, we can provide services below the guest operating system without trusting or modifying it. We believe providing services at this layer are especially useful for enhancing security and mobility. This position paper describes the general benefits and challenges that arise from running most applications in a virtual machine, and then describes some example services and alternative ways to provide those services.

  3. Machining of Additively Manufactured Parts: Implications for Surface Integrity

    OpenAIRE

    Oyelola, O.; Crawforth, P.; M'Saoubi, R.; Clare, A.T.

    2016-01-01

    Additive manufacturing methods continue to move towards production ready technologies with the widely extolled virtues of rapid transition from design to part and enhanced design freedoms. However, due to fundamental limitations of laser based processes for metal additive manufacturing, there is a significant ongoing need for these parts to be subject to additional machining operations. This paper reports on a study to investigate the machining behavior and surface integrity of Ti-6Al-4 V com...

  4. Machining of Additively Manufactured Parts: Implications for Surface Integrity

    OpenAIRE

    Oyelola, O.; Crawforth, P.; M'Saoubi, R.; Clare, A.T.

    2016-01-01

    Additive manufacturing methods continue to move towards production ready technologies with the widely extolled virtues of rapid transition from design to part and enhanced design freedoms. However, due to fundamental limitations of laser based processes for metal additive manufacturing, there is a significant ongoing need for these parts to be subject to additional machining operations. This paper reports on a study to investigate the machining behavior and surface integrity of Ti-6Al-4 V com...

  5. Binary Laser Direct Writing System and Its Applications

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    A new laser direct writing system is introduced and the potential application of the diffractive optical elements (DOE's) fabricated by applying laser direct writing system are presented. The fabrication techniques by applying the laser direct writing are developed. Experimental results have been obtained by applying laser direct writing machine with line width of 5μm and 10μm.

  6. Process control & monitoring for laser micromaching of Si3N4 ceramics

    CSIR Research Space (South Africa)

    Tshabalala, L

    2012-09-01

    Full Text Available Laser machining which is a non-contact process that offers the advantage of machining advanced ceramics. In laser machining Si3N4, surface temperature is increased and controlled to evaporate the YSiAlON glassy phase of the Si3N4. However...

  7. Stirling machine operating experience

    Energy Technology Data Exchange (ETDEWEB)

    Ross, B. [Stirling Technology Co., Richland, WA (United States); Dudenhoefer, J.E. [Lewis Research Center, Cleveland, OH (United States)

    1994-09-01

    Numerous Stirling machines have been built and operated, but the operating experience of these machines is not well known. It is important to examine this operating experience in detail, because it largely substantiates the claim that stirling machines are capable of reliable and lengthy operating lives. The amount of data that exists is impressive, considering that many of the machines that have been built are developmental machines intended to show proof of concept, and are not expected to operate for lengthy periods of time. Some Stirling machines (typically free-piston machines) achieve long life through non-contact bearings, while other Stirling machines (typically kinematic) have achieved long operating lives through regular seal and bearing replacements. In addition to engine and system testing, life testing of critical components is also considered. The record in this paper is not complete, due to the reluctance of some organizations to release operational data and because several organizations were not contacted. The authors intend to repeat this assessment in three years, hoping for even greater participation.

  8. Perpetual Motion Machine

    Directory of Open Access Journals (Sweden)

    D. Tsaousis

    2008-01-01

    Full Text Available Ever since the first century A.D. there have been relative descriptions of known devices as well as manufactures for the creation of perpetual motion machines. Although physics has led, with two thermodynamic laws, to the opinion that a perpetual motion machine is impossible to be manufactured, inventors of every age and educational level appear to claim that they have invented something «entirely new» or they have improved somebody else’s invention, which «will function henceforth perpetually»! However the fact of the failure in manufacturing a perpetual motion machine till now, it does not mean that countless historical elements for these fictional machines become indifferent. The discussion on every version of a perpetual motion machine on the one hand gives the chance to comprehend the inventor’s of each period level of knowledge and his way of thinking, and on the other hand, to locate the points where this «perpetual motion machine» clashes with the laws of nature and that’s why it is impossible to have been manufactured or have functioned. The presentation of a new «perpetual motion machine» has excited our interest to locate its weak points. According to the designer of it the machine functions with the work produced by the buoyant force

  9. Machine Intelligence and Explication

    NARCIS (Netherlands)

    Wieringa, Roelf J.

    1987-01-01

    This report is an MA ("doctoraal") thesis submitted to the department of philosophy, university of Amsterdam. It attempts to answer the question whether machines can think by conceptual analysis. Ideally. a conceptual analysis should give plausible explications of the concepts of "machine" and "inte

  10. Microsoft Azure machine learning

    CERN Document Server

    Mund, Sumit

    2015-01-01

    The book is intended for those who want to learn how to use Azure Machine Learning. Perhaps you already know a bit about Machine Learning, but have never used ML Studio in Azure; or perhaps you are an absolute newbie. In either case, this book will get you up-and-running quickly.

  11. Reactive Turing machines

    NARCIS (Netherlands)

    Baeten, J.C.M.; Luttik, B.; Tilburg, P.J.A. van

    2013-01-01

    We propose reactive Turing machines (RTMs), extending classical Turing machines with a process-theoretical notion of interaction, and use it to define a notion of executable transition system. We show that every computable transition system with a bounded branching degree is simulated modulo diverge

  12. Machine Intelligence and Explication

    NARCIS (Netherlands)

    Wieringa, Roel

    1987-01-01

    This report is an MA ("doctoraal") thesis submitted to the department of philosophy, university of Amsterdam. It attempts to answer the question whether machines can think by conceptual analysis. Ideally. a conceptual analysis should give plausible explications of the concepts of "machine" and "inte

  13. Coordinate measuring machines

    DEFF Research Database (Denmark)

    De Chiffre, Leonardo

    This document is used in connection with three exercises of 2 hours duration as a part of the course GEOMETRICAL METROLOGY AND MACHINE TESTING. The exercises concern three aspects of coordinate measuring: 1) Measuring and verification of tolerances on coordinate measuring machines, 2) Traceability...

  14. Simple Machine Junk Cars

    Science.gov (United States)

    Herald, Christine

    2010-01-01

    During the month of May, the author's eighth-grade physical science students study the six simple machines through hands-on activities, reading assignments, videos, and notes. At the end of the month, they can easily identify the six types of simple machine: inclined plane, wheel and axle, pulley, screw, wedge, and lever. To conclude this unit,…

  15. Human Machine Learning Symbiosis

    Science.gov (United States)

    Walsh, Kenneth R.; Hoque, Md Tamjidul; Williams, Kim H.

    2017-01-01

    Human Machine Learning Symbiosis is a cooperative system where both the human learner and the machine learner learn from each other to create an effective and efficient learning environment adapted to the needs of the human learner. Such a system can be used in online learning modules so that the modules adapt to each learner's learning state both…

  16. Machine learning with R

    CERN Document Server

    Lantz, Brett

    2015-01-01

    Perhaps you already know a bit about machine learning but have never used R, or perhaps you know a little R but are new to machine learning. In either case, this book will get you up and running quickly. It would be helpful to have a bit of familiarity with basic programming concepts, but no prior experience is required.

  17. Machine Phase Fullerene Nanotechnology: 1996

    Science.gov (United States)

    Globus, Al; Chancellor, Marisa K. (Technical Monitor)

    1997-01-01

    NASA has used exotic materials for spacecraft and experimental aircraft to good effect for many decades. In spite of many advances, transportation to space still costs about $10,000 per pound. Drexler has proposed a hypothetical nanotechnology based on diamond and investigated the properties of such molecular systems. These studies and others suggest enormous potential for aerospace systems. Unfortunately, methods to realize diamonoid nanotechnology are at best highly speculative. Recent computational efforts at NASA Ames Research Center and computation and experiment elsewhere suggest that a nanotechnology of machine phase functionalized fullerenes may be synthetically relatively accessible and of great aerospace interest. Machine phase materials are (hypothetical) materials consisting entirely or in large part of microscopic machines. In a sense, most living matter fits this definition. To begin investigation of fullerene nanotechnology, we used molecular dynamics to study the properties of carbon nanotube based gears and gear/shaft configurations. Experiments on C60 and quantum calculations suggest that benzyne may react with carbon nanotubes to form gear teeth. Han has computationally demonstrated that molecular gears fashioned from (14,0) single-walled carbon nanotubes and benzyne teeth should operate well at 50-100 gigahertz. Results suggest that rotation can be converted to rotating or linear motion, and linear motion may be converted into rotation. Preliminary results suggest that these mechanical systems can be cooled by a helium atmosphere. Furthermore, Deepak has successfully simulated using helical electric fields generated by a laser to power fullerene gears once a positive and negative charge have been added to form a dipole. Even with mechanical motion, cooling, and power; creating a viable nanotechnology requires support structures, computer control, a system architecture, a variety of components, and some approach to manufacture. Additional

  18. 15 CFR 700.31 - Metalworking machines.

    Science.gov (United States)

    2010-01-01

    ... Drilling and tapping machines Electrical discharge, ultrasonic and chemical erosion machines Forging..., power driven Machining centers and way-type machines Manual presses Mechanical presses, power...

  19. LHC Report: machine development

    CERN Multimedia

    Rogelio Tomás García for the LHC team

    2015-01-01

    Machine development weeks are carefully planned in the LHC operation schedule to optimise and further study the performance of the machine. The first machine development session of Run 2 ended on Saturday, 25 July. Despite various hiccoughs, it allowed the operators to make great strides towards improving the long-term performance of the LHC.   The main goals of this first machine development (MD) week were to determine the minimum beam-spot size at the interaction points given existing optics and collimation constraints; to test new beam instrumentation; to evaluate the effectiveness of performing part of the beam-squeezing process during the energy ramp; and to explore the limits on the number of protons per bunch arising from the electromagnetic interactions with the accelerator environment and the other beam. Unfortunately, a series of events reduced the machine availability for studies to about 50%. The most critical issue was the recurrent trip of a sextupolar corrector circuit –...

  20. Micro-machining.

    Science.gov (United States)

    Brinksmeier, Ekkard; Preuss, Werner

    2012-08-28

    Manipulating bulk material at the atomic level is considered to be the domain of physics, chemistry and nanotechnology. However, precision engineering, especially micro-machining, has become a powerful tool for controlling the surface properties and sub-surface integrity of the optical, electronic and mechanical functional parts in a regime where continuum mechanics is left behind and the quantum nature of matter comes into play. The surprising subtlety of micro-machining results from the extraordinary precision of tools, machines and controls expanding into the nanometre range-a hundred times more precise than the wavelength of light. In this paper, we will outline the development of precision engineering, highlight modern achievements of ultra-precision machining and discuss the necessity of a deeper physical understanding of micro-machining.

  1. Introduction to machine learning.

    Science.gov (United States)

    Baştanlar, Yalin; Ozuysal, Mustafa

    2014-01-01

    The machine learning field, which can be briefly defined as enabling computers make successful predictions using past experiences, has exhibited an impressive development recently with the help of the rapid increase in the storage capacity and processing power of computers. Together with many other disciplines, machine learning methods have been widely employed in bioinformatics. The difficulties and cost of biological analyses have led to the development of sophisticated machine learning approaches for this application area. In this chapter, we first review the fundamental concepts of machine learning such as feature assessment, unsupervised versus supervised learning and types of classification. Then, we point out the main issues of designing machine learning experiments and their performance evaluation. Finally, we introduce some supervised learning methods.

  2. Feed Drive Based upon Linear Motor for Ultraprecision Turning Machine

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    The characteristics of several different linear motors have been investigated, and the feed drive system with linear motor instead of screw-nut mechanism has been built for a submicro ultraprecision turning machine. In the control system for the feed drive system arranged as "T", both P-position and PI-speed control loops are used. The feedback variable is obtained from a double frequecy laser interferometor. Experiments show that the feed drive with linear motor is simple in construction, and that its dynamics is better than others. So the machining accuracy of the workpiece machined has been successfully improved.

  3. Micromachining using femtosecond lasers

    Science.gov (United States)

    Toenshoff, Hans K.; Ostendorf, Andreas; Nolte, Stefan; Korte, Frank; Bauer, Thorsten

    2000-11-01

    Femtosecond laser systems have been proved to be effective tools for high precision micro-machining. Almost all solid materials can be processed with high precision. The dependence on material properties like thermal conductivity, transparency, heat- or shock sensitivity is strongly reduced and no significant influence on the remaining bulk material is observed after ablation using femtosecond laser pulses. In contrast to conventional laser processing, where the achievable precision is reduced due to a formed liquid phase causing burr formation, the achievable precision using femtosecond pulses is only limited by the diffraction of the used optics. Potential applications of this technique, aincluding the structuring of biodegradable polymers for cardiovascular implants, so-called stents, as well as high precision machining of transparent materials are presented.

  4. Laser Beam Focus Analyser

    DEFF Research Database (Denmark)

    Nielsen, Peter Carøe; Hansen, Hans Nørgaard; Olsen, Flemming Ove

    2007-01-01

    The quantitative and qualitative description of laser beam characteristics is important for process implementation and optimisation. In particular, a need for quantitative characterisation of beam diameter was identified when using fibre lasers for micro manufacturing. Here the beam diameter limits...... the obtainable features in direct laser machining as well as heat affected zones in welding processes. This paper describes the development of a measuring unit capable of analysing beam shape and diameter of lasers to be used in manufacturing processes. The analyser is based on the principle of a rotating...... mechanical wire being swept through the laser beam at varying Z-heights. The reflected signal is analysed and the resulting beam profile determined. The development comprised the design of a flexible fixture capable of providing both rotation and Z-axis movement, control software including data capture...

  5. CERN's web application updates for electron and laser beam technologies

    CERN Document Server

    Sigas, Christos

    2017-01-01

    This report describes the modifications at CERN's web application for electron and laser beam technologies. There are updates at both the front and the back end of the application. New electron and laser machines were added and also old machines were updated. There is also a new feature for printing needed information.

  6. Improvement of the surface finish obtained by laser ablation with a Nd: YAG laser on pre-ablated tool steel

    CSIR Research Space (South Africa)

    Steyn, J

    2007-01-01

    Full Text Available Surface finish is an important requirement for tool and die makers and remains a challenge with conventional machining technologies. Nd: YAG lasers have been utilised for many years in the area of laser marking, engraving and micro machining...

  7. Machine Learning and Radiology

    Science.gov (United States)

    Wang, Shijun; Summers, Ronald M.

    2012-01-01

    In this paper, we give a short introduction to machine learning and survey its applications in radiology. We focused on six categories of applications in radiology: medical image segmentation, registration, computer aided detection and diagnosis, brain function or activity analysis and neurological disease diagnosis from fMR images, content-based image retrieval systems for CT or MRI images, and text analysis of radiology reports using natural language processing (NLP) and natural language understanding (NLU). This survey shows that machine learning plays a key role in many radiology applications. Machine learning identifies complex patterns automatically and helps radiologists make intelligent decisions on radiology data such as conventional radiographs, CT, MRI, and PET images and radiology reports. In many applications, the performance of machine learning-based automatic detection and diagnosis systems has shown to be comparable to that of a well-trained and experienced radiologist. Technology development in machine learning and radiology will benefit from each other in the long run. Key contributions and common characteristics of machine learning techniques in radiology are discussed. We also discuss the problem of translating machine learning applications to the radiology clinical setting, including advantages and potential barriers. PMID:22465077

  8. The basic anaesthesia machine.

    Science.gov (United States)

    Gurudatt, Cl

    2013-09-01

    After WTG Morton's first public demonstration in 1846 of use of ether as an anaesthetic agent, for many years anaesthesiologists did not require a machine to deliver anaesthesia to the patients. After the introduction of oxygen and nitrous oxide in the form of compressed gases in cylinders, there was a necessity for mounting these cylinders on a metal frame. This stimulated many people to attempt to construct the anaesthesia machine. HEG Boyle in the year 1917 modified the Gwathmey's machine and this became popular as Boyle anaesthesia machine. Though a lot of changes have been made for the original Boyle machine still the basic structure remains the same. All the subsequent changes which have been brought are mainly to improve the safety of the patients. Knowing the details of the basic machine will make the trainee to understand the additional improvements. It is also important for every practicing anaesthesiologist to have a thorough knowledge of the basic anaesthesia machine for safe conduct of anaesthesia.

  9. The basic anaesthesia machine

    Directory of Open Access Journals (Sweden)

    C L Gurudatt

    2013-01-01

    Full Text Available After WTG Morton′s first public demonstration in 1846 of use of ether as an anaesthetic agent, for many years anaesthesiologists did not require a machine to deliver anaesthesia to the patients. After the introduction of oxygen and nitrous oxide in the form of compressed gases in cylinders, there was a necessity for mounting these cylinders on a metal frame. This stimulated many people to attempt to construct the anaesthesia machine. HEG Boyle in the year 1917 modified the Gwathmey′s machine and this became popular as Boyle anaesthesia machine. Though a lot of changes have been made for the original Boyle machine still the basic structure remains the same. All the subsequent changes which have been brought are mainly to improve the safety of the patients. Knowing the details of the basic machine will make the trainee to understand the additional improvements. It is also important for every practicing anaesthesiologist to have a thorough knowledge of the basic anaesthesia machine for safe conduct of anaesthesia.

  10. Part Machinability Evaluation System

    Institute of Scientific and Technical Information of China (English)

    1999-01-01

    In the early design period, estimation of the part or the whole product machinability is useful to consider the function and process request of the product at the same time so as to globally optimize the design decision. This paper presents a part machinability evaluation system, discusses the general restrictions of part machinability, and realizes the inspection of these restrictions with the relation between tool scan space and part model. During the system development, the expansibility and understandability were considered, and an independent restriction algorithm library and a general function library were set up. Additionally, the system has an interpreter and a knowledge manager.

  11. Fundamentals of machine design

    CERN Document Server

    Karaszewski, Waldemar

    2011-01-01

    A forum of researchers, educators and engineers involved in various aspects of Machine Design provided the inspiration for this collection of peer-reviewed papers. The resultant dissemination of the latest research results, and the exchange of views concerning the future research directions to be taken in this field will make the work of immense value to all those having an interest in the topics covered. The book reflects the cooperative efforts made in seeking out the best strategies for effecting improvements in the quality and the reliability of machines and machine parts and for extending

  12. Machine Tool Software

    Science.gov (United States)

    1988-01-01

    A NASA-developed software package has played a part in technical education of students who major in Mechanical Engineering Technology at William Rainey Harper College. Professor Hack has been using (APT) Automatically Programmed Tool Software since 1969 in his CAD/CAM Computer Aided Design and Manufacturing curriculum. Professor Hack teaches the use of APT programming languages for control of metal cutting machines. Machine tool instructions are geometry definitions written in APT Language to constitute a "part program." The part program is processed by the machine tool. CAD/CAM students go from writing a program to cutting steel in the course of a semester.

  13. Analysis of synchronous machines

    CERN Document Server

    Lipo, TA

    2012-01-01

    Analysis of Synchronous Machines, Second Edition is a thoroughly modern treatment of an old subject. Courses generally teach about synchronous machines by introducing the steady-state per phase equivalent circuit without a clear, thorough presentation of the source of this circuit representation, which is a crucial aspect. Taking a different approach, this book provides a deeper understanding of complex electromechanical drives. Focusing on the terminal rather than on the internal characteristics of machines, the book begins with the general concept of winding functions, describing the placeme

  14. Database machine performance

    Energy Technology Data Exchange (ETDEWEB)

    Cesarini, F.; Salza, S.

    1987-01-01

    This book is devoted to the important problem of database machine performance evaluation. The book presents several methodological proposals and case studies, that have been developed within an international project supported by the European Economic Community on Database Machine Evaluation Techniques and Tools in the Context of the Real Time Processing. The book gives an overall view of the modeling methodologies and the evaluation strategies that can be adopted to analyze the performance of the database machine. Moreover, it includes interesting case studies and an extensive bibliography.

  15. Virtual Machine Introspection

    Directory of Open Access Journals (Sweden)

    S C Rachana

    2014-06-01

    Full Text Available Cloud computing is an Internet-based computing solution which provides the resources in an effective manner. A very serious issue in cloud computing is security which is a major obstacle for the adoption of cloud. The most important threats of cloud computing are Multitenancy, Availability, Loss of control, Loss of Data, outside attacks, DOS attacks, malicious insiders, etc. Among many security issues in cloud, the Virtual Machine Security is one of the very serious issues. Thus, monitoring of virtual machine is essential. The paper proposes a Virtual Network Introspection [VMI] System to secure the Virtual machines from Distributed Denial of Service [DDOS] and Zombie attacks.

  16. Virtual Machine Introspection

    Directory of Open Access Journals (Sweden)

    S C Rachana

    2015-11-01

    Full Text Available Cloud computing is an Internet-based computing solution which provides the resources in an effective manner. A very serious issue in cloud computing is security which is a major obstacle for the adoption of cloud. The most important threats of cloud computing are Multitenancy, Availability, Loss of control, Loss of Data, outside attacks, DOS attacks, malicious insiders, etc. Among many security issues in cloud, the Virtual Machine Security is one of the very serious issues. Thus, monitoring of virtual machine is essential. The paper proposes a Virtual Network Introspection [VMI] System to secure the Virtual machines from Distributed Denial of Service [DDOS] and Zombie attacks.

  17. Machine Learning for Hackers

    CERN Document Server

    Conway, Drew

    2012-01-01

    If you're an experienced programmer interested in crunching data, this book will get you started with machine learning-a toolkit of algorithms that enables computers to train themselves to automate useful tasks. Authors Drew Conway and John Myles White help you understand machine learning and statistics tools through a series of hands-on case studies, instead of a traditional math-heavy presentation. Each chapter focuses on a specific problem in machine learning, such as classification, prediction, optimization, and recommendation. Using the R programming language, you'll learn how to analyz

  18. Laser processing of materials

    Indian Academy of Sciences (India)

    J Dutta Majumdar; I Manna

    2003-06-01

    Light amplification by stimulated emission of radiation (laser) is a coherent and monochromatic beam of electromagnetic radiation that can propagate in a straight line with negligible divergence and occur in a wide range of wavelength, energy/power and beam-modes/configurations. As a result, lasers find wide applications in the mundane to the most sophisticated devices, in commercial to purely scientific purposes, and in life-saving as well as life-threatening causes. In the present contribution, we provide an overview of the application of lasers for material processing. The processes covered are broadly divided into four major categories; namely, laser-assisted forming, joining, machining and surface engineering. Apart from briefly introducing the fundamentals of these operations, we present an updated review of the relevant literature to highlight the recent advances and open questions. We begin our discussion with the general applications of lasers, fundamentals of laser-matter interaction and classification of laser material processing. A major part of the discussion focuses on laser surface engineering that has attracted a good deal of attention from the scientific community for its technological significance and scientific challenges. In this regard, a special mention is made about laser surface vitrification or amorphization that remains a very attractive but unaccomplished proposition.

  19. Trends in laser micromachining

    Science.gov (United States)

    Gaebler, Frank; van Nunen, Joris; Held, Andrew

    2016-03-01

    Laser Micromachining is well established in industry. Depending on the application lasers with pulse length from μseconds to femtoseconds and wavelengths from 1064nm and its harmonics up to 5μm or 10.6μm are used. Ultrafast laser machining using pulses with pico or femtosecond duration pulses is gaining traction, as it offers very precise processing of materials with low thermal impact. Large-scale industrial ultrafast laser applications show that the market can be divided into various sub segments. One set of applications demand low power around 10W, compact footprint and are extremely sensitive to the laser price whilst still demanding 10ps or shorter laser pulses. A second set of applications are very power hungry and only become economically feasible for large scale deployments at power levels in the 100+W class. There is also a growing demand for applications requiring fs-laser pulses. In our presentation we would like to describe these sub segments by using selected applications from the automotive and electronics industry e.g. drilling of gas/diesel injection nozzles, dicing of LED substrates. We close the presentation with an outlook to micromachining applications e.g. glass cutting and foil processing with unique new CO lasers emitting 5μm laser wavelength.

  20. Welle tecnologia laser internationalization analysis US market

    OpenAIRE

    2016-01-01

    Welle Laser is a Brazilian company that manufactures marking and engraving machines mainly for large-scale industry segments providing solutions that help increase productivity. Welle laser has 60% market share in Brazil and decided to go internationally in 2015, mainly to increase revenues and diversify business risks. Welle opened an office in Switzerland and celebrated a contract with a Mexican company to distribute their machines in Mexico. The next step for Welle is expanding its operati...

  1. Some relations between quantum Turing machines and Turing machines

    CERN Document Server

    Sicard, A; Sicard, Andrés; Vélez, Mario

    1999-01-01

    For quantum Turing machines we present three elements: Its components, its time evolution operator and its local transition function. The components are related with deterministic Turing machines, the time evolution operator is related with reversible Turing machines and the local transition function is related with probabilistic and reversible Turing machines.

  2. Machining of hard-to-machine materials

    OpenAIRE

    2016-01-01

    Bakalářská práce se zabývá studiem obrábění těžkoobrobitelných materiálů. V první části jsou rozděleny těžkoobrobitelné materiály a následuje jejich analýza. V další části se práce zaměřuje na problematiku obrobitelnosti jednotlivých slitin. Závěrečná část práce je věnovaná experimentu, jeho statistickému zpracování a nakonec následnému vyhodnocení. This bachelor thesis studies the machining of hard-to-machine materials. The first part of the thesis considers hard-to-machine materials and ...

  3. Machine (bulk) harvest

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This is a summary of machine harvesting activities on Neal Smith National Wildlife Refuge between 1991 and 2008. Information is provided for each year about...

  4. Machine Vision Handbook

    CERN Document Server

    2012-01-01

    The automation of visual inspection is becoming more and more important in modern industry as a consistent, reliable means of judging the quality of raw materials and manufactured goods . The Machine Vision Handbook  equips the reader with the practical details required to engineer integrated mechanical-optical-electronic-software systems. Machine vision is first set in the context of basic information on light, natural vision, colour sensing and optics. The physical apparatus required for mechanized image capture – lenses, cameras, scanners and light sources – are discussed followed by detailed treatment of various image-processing methods including an introduction to the QT image processing system. QT is unique to this book, and provides an example of a practical machine vision system along with extensive libraries of useful commands, functions and images which can be implemented by the reader. The main text of the book is completed by studies of a wide variety of applications of machine vision in insp...

  5. Tests of Machine Intelligence

    CERN Document Server

    Legg, Shane

    2007-01-01

    Although the definition and measurement of intelligence is clearly of fundamental importance to the field of artificial intelligence, no general survey of definitions and tests of machine intelligence exists. Indeed few researchers are even aware of alternatives to the Turing test and its many derivatives. In this paper we fill this gap by providing a short survey of the many tests of machine intelligence that have been proposed.

  6. Metalworking and machining fluids

    Science.gov (United States)

    Erdemir, Ali; Sykora, Frank; Dorbeck, Mark

    2010-10-12

    Improved boron-based metal working and machining fluids. Boric acid and boron-based additives that, when mixed with certain carrier fluids, such as water, cellulose and/or cellulose derivatives, polyhydric alcohol, polyalkylene glycol, polyvinyl alcohol, starch, dextrin, in solid and/or solvated forms result in improved metalworking and machining of metallic work pieces. Fluids manufactured with boric acid or boron-based additives effectively reduce friction, prevent galling and severe wear problems on cutting and forming tools.

  7. mlpy: Machine Learning Python

    CERN Document Server

    Albanese, Davide; Merler, Stefano; Riccadonna, Samantha; Jurman, Giuseppe; Furlanello, Cesare

    2012-01-01

    mlpy is a Python Open Source Machine Learning library built on top of NumPy/SciPy and the GNU Scientific Libraries. mlpy provides a wide range of state-of-the-art machine learning methods for supervised and unsupervised problems and it is aimed at finding a reasonable compromise among modularity, maintainability, reproducibility, usability and efficiency. mlpy is multiplatform, it works with Python 2 and 3 and it is distributed under GPL3 at the website http://mlpy.fbk.eu.

  8. Human-machine interactions

    Science.gov (United States)

    Forsythe, J. Chris; Xavier, Patrick G.; Abbott, Robert G.; Brannon, Nathan G.; Bernard, Michael L.; Speed, Ann E.

    2009-04-28

    Digital technology utilizing a cognitive model based on human naturalistic decision-making processes, including pattern recognition and episodic memory, can reduce the dependency of human-machine interactions on the abilities of a human user and can enable a machine to more closely emulate human-like responses. Such a cognitive model can enable digital technology to use cognitive capacities fundamental to human-like communication and cooperation to interact with humans.

  9. Machine Learning with Distances

    Science.gov (United States)

    2015-02-16

    and demonstrated their usefulness in experiments. 1 Introduction The goal of machine learning is to find useful knowledge behind data. Many machine...212, 172]. However, direct divergence approximators still suffer from the curse of dimensionality. A possible cure for this problem is to combine them...obtain the global optimal solution or even a good local solution without any prior knowledge . For this reason, we decided to introduce the unit-norm

  10. mlpy: Machine Learning Python

    OpenAIRE

    Albanese, Davide; Visintainer, Roberto; Merler, Stefano; Riccadonna, Samantha; Jurman, Giuseppe; Furlanello, Cesare

    2012-01-01

    mlpy is a Python Open Source Machine Learning library built on top of NumPy/SciPy and the GNU Scientific Libraries. mlpy provides a wide range of state-of-the-art machine learning methods for supervised and unsupervised problems and it is aimed at finding a reasonable compromise among modularity, maintainability, reproducibility, usability and efficiency. mlpy is multiplatform, it works with Python 2 and 3 and it is distributed under GPL3 at the website http://mlpy.fbk.eu.

  11. 6种虫媒病毒微孔膜芯片检测方法的研制与应用%Development and application of microwell membrane array for detection of six species of arboviruses

    Institute of Scientific and Technical Information of China (English)

    郑夔; 丁国允; 李小波; 师永霞; 苏锦坤; 黄吉城

    2012-01-01

    目的 研制能同时检测6种口岸重要虫媒病毒的微孔膜芯片.方法 针对包括1~4型登革病毒、乙型脑炎病毒、西尼罗病毒、黄热病毒、基孔肯雅病毒和裂谷热病毒等6种虫媒病毒,选择合适的保守基因,设计特异性的PCR引物(5'端标记生物素)和检测探针,通过参数优化建立单管多重RT-PCR扩增体系;然后按每个阵列5×5的格式,并确保点样区域为96孔板的微孔大小,将探针喷点到处理后的尼龙膜上,通过条件优化建立稳定的PCR产物与固化探针的杂交体系;采用碱性磷酸酯酶标记链亲和素和化学显色底物NBT/BCIP来检测特异性的PCR杂交产物.选取2012年1-6月份从口岸输入的疑似登革热发热病例的临床血清标本,提取RNA后,直接采用本研究建立的微孔膜芯片进行未知虫媒病毒的快速检测.结果 用1~4型登革病毒、乙型脑炎病毒、西尼罗病毒和基孔肯雅病毒等7种毒株、1种黄热病毒疫苗株和1种裂谷热病毒核酸体外转录的RNA模板验证已建立的微孔膜芯片,获得比较特异和稳定的实验结果.应用该研究建立的方法,从3份疑似登革热发热病例的临床血清标本中检出了1例登革1型病毒和2例登革2型病毒,与实时荧光PCR检测结果相符.结论 该研究建立的6种虫媒病毒微孔膜芯片检测方法,具有快速、准确、自动化和高通量等特点,为快速应对口岸输入性发热病例提供了非常有价值的检测手段,也为进一步开发更多指标的病原体检测方法提供良好的示范作用.%Objective To develop a microwell membrane array for simultaneous detection of six species of important arboviruses at frontier port. Methods Specific PCR primers labeled with biotin and ol-igonucleotide probes were designed based on the sequence of conservative genes of six arboviruses specises, including four serotypes of dengue virus, Japanese encephalitis virus, West Nile virus, Yellow Fever

  12. EVALUATION OF MACHINE TOOL QUALITY

    Directory of Open Access Journals (Sweden)

    Ivan Kuric

    2011-12-01

    Full Text Available Paper deals with aspects of quality and accuracy of machine tools. As the accuracy of machine tools has key factor for product quality, it is important to know the methods for evaluation of quality and accuracy of machine tools. Several aspects of diagnostics of machine tools are described, such as aspects of reliability.

  13. An HTS machine laboratory prototype

    DEFF Research Database (Denmark)

    Mijatovic, Nenad; Jensen, Bogi Bech; Træholt, Chresten

    2012-01-01

    This paper describes Superwind HTS machine laboratory setup which is a small scale HTS machine designed and build as a part of the efforts to identify and tackle some of the challenges the HTS machine design may face. One of the challenges of HTS machines is a Torque Transfer Element (TTE) which...

  14. Munition Mass Properties Measurement Procedures Using a Spin Balance Machine

    Science.gov (United States)

    2015-03-09

    alignment fixtures, and the calibration tools (fixtures, laser alignment/pointing device, mechanical dial indicator, etc). There should be a crane hoist ...the measured quantity which consistently causes the output of the measuring machine to change. It is largely a function of friction in mechanical

  15. Machining of Metal Matrix Composites

    CERN Document Server

    2012-01-01

    Machining of Metal Matrix Composites provides the fundamentals and recent advances in the study of machining of metal matrix composites (MMCs). Each chapter is written by an international expert in this important field of research. Machining of Metal Matrix Composites gives the reader information on machining of MMCs with a special emphasis on aluminium matrix composites. Chapter 1 provides the mechanics and modelling of chip formation for traditional machining processes. Chapter 2 is dedicated to surface integrity when machining MMCs. Chapter 3 describes the machinability aspects of MMCs. Chapter 4 contains information on traditional machining processes and Chapter 5 is dedicated to the grinding of MMCs. Chapter 6 describes the dry cutting of MMCs with SiC particulate reinforcement. Finally, Chapter 7 is dedicated to computational methods and optimization in the machining of MMCs. Machining of Metal Matrix Composites can serve as a useful reference for academics, manufacturing and materials researchers, manu...

  16. Optimal interference code based on machine learning

    Science.gov (United States)

    Qian, Ye; Chen, Qian; Hu, Xiaobo; Cao, Ercong; Qian, Weixian; Gu, Guohua

    2016-10-01

    In this paper, we analyze the characteristics of pseudo-random code, by the case of m sequence. Depending on the description of coding theory, we introduce the jamming methods. We simulate the interference effect or probability model by the means of MATLAB to consolidate. In accordance with the length of decoding time the adversary spends, we find out the optimal formula and optimal coefficients based on machine learning, then we get the new optimal interference code. First, when it comes to the phase of recognition, this study judges the effect of interference by the way of simulating the length of time over the decoding period of laser seeker. Then, we use laser active deception jamming simulate interference process in the tracking phase in the next block. In this study we choose the method of laser active deception jamming. In order to improve the performance of the interference, this paper simulates the model by MATLAB software. We find out the least number of pulse intervals which must be received, then we can make the conclusion that the precise interval number of the laser pointer for m sequence encoding. In order to find the shortest space, we make the choice of the greatest common divisor method. Then, combining with the coding regularity that has been found before, we restore pulse interval of pseudo-random code, which has been already received. Finally, we can control the time period of laser interference, get the optimal interference code, and also increase the probability of interference as well.

  17. Laser Processing of High-Tech Materials at High Irradiance.

    Science.gov (United States)

    1987-05-13

    CHARGED PARTICLES (Electrons, Ions, Plasma) * "PHOTONS LASER IMPULSE VAPOR SPALLATION CRATER SHOCK WAVE THERMAL WAVE Fig. I - Interaction of a high...metals. 2ŗ𔃾 Shaping includes drilling , cutting, bending, laser assisted machining (turning and milling) and direct laser machining. Joining includes...induces a tensile stress which can be sufficient to exceed the material’s strength. This dynamic fracture of material is called spallation . Although

  18. Error Model and Accuracy Calibration of 5-Axis Machine Tool

    Directory of Open Access Journals (Sweden)

    Fangyu Pan

    2013-08-01

    Full Text Available To improve the machining precision and reduce the geometric errors for 5-axis machinetool, error model and calibration are presented in this paper. Error model is realized by the theory of multi-body system and characteristic matrixes, which can establish the relationship between the cutting tool and the workpiece in theory. The accuracy calibration was difficult to achieve, but by a laser approach-laser interferometer and laser tracker, the errors can be displayed accurately which is benefit for later compensation.

  19. Non-conventional electrical machines

    CERN Document Server

    Rezzoug, Abderrezak

    2013-01-01

    The developments of electrical machines are due to the convergence of material progress, improved calculation tools, and new feeding sources. Among the many recent machines, the authors have chosen, in this first book, to relate the progress in slow speed machines, high speed machines, and superconducting machines. The first part of the book is dedicated to materials and an overview of magnetism, mechanic, and heat transfer.

  20. Dielectric laser accelerators

    Science.gov (United States)

    England, R. Joel; Noble, Robert J.; Bane, Karl; Dowell, David H.; Ng, Cho-Kuen; Spencer, James E.; Tantawi, Sami; Wu, Ziran; Byer, Robert L.; Peralta, Edgar; Soong, Ken; Chang, Chia-Ming; Montazeri, Behnam; Wolf, Stephen J.; Cowan, Benjamin; Dawson, Jay; Gai, Wei; Hommelhoff, Peter; Huang, Yen-Chieh; Jing, Chunguang; McGuinness, Christopher; Palmer, Robert B.; Naranjo, Brian; Rosenzweig, James; Travish, Gil; Mizrahi, Amit; Schachter, Levi; Sears, Christopher; Werner, Gregory R.; Yoder, Rodney B.

    2014-10-01

    The use of infrared lasers to power optical-scale lithographically fabricated particle accelerators is a developing area of research that has garnered increasing interest in recent years. The physics and technology of this approach is reviewed, which is referred to as dielectric laser acceleration (DLA). In the DLA scheme operating at typical laser pulse lengths of 0.1 to 1 ps, the laser damage fluences for robust dielectric materials correspond to peak surface electric fields in the GV /m regime. The corresponding accelerating field enhancement represents a potential reduction in active length of the accelerator between 1 and 2 orders of magnitude. Power sources for DLA-based accelerators (lasers) are less costly than microwave sources (klystrons) for equivalent average power levels due to wider availability and private sector investment. Because of the high laser-to-particle coupling efficiency, required pulse energies are consistent with tabletop microJoule class lasers. Combined with the very high (MHz) repetition rates these lasers can provide, the DLA approach appears promising for a variety of applications, including future high-energy physics colliders, compact light sources, and portable medical scanners and radiative therapy machines.

  1. Design of the cutting head position detection and control system of Laser cutting machine%激光切割机切割头位置检测与调高控制系统设计

    Institute of Scientific and Technical Information of China (English)

    李建新

    2012-01-01

    在激光切割中为了有敢控制激光焦点与工件之间的相对位置,设计了激光切割头自动调高系统的位置检测系统。采用切割喷嘴和切割极板形成的电容构成差动式电桥,以差动式电桥作为测距传感器;用相敏检波电路鉴别切割喷嘴和切割板材间位置变化,伺服系统控制切割头运动,从而实现激光切割头高度调节。通过测试,有效地解决了激光切割焦点跟踪问题,提高了系统的控制品质。所设计的切割头位置检测为激光切割机提供了解决方案。%In order to control effectively the opposite position between the laser focus and the workpiece during laser beam cutting, the position examination system of the laser cutting head automatic distance control system has been designed. To adopt the electric capacity of the cutting nozzle and the cutting workpiece constitutes the differential type electricity bridge, it is used as distance sensor. The phase- sensitive detection electric circuit is used to discriminate the position change between the cutting nozzle and the workpiece, the sorvo system controles cutting head movement, the high regulate for the laser cutting head was implemented. Pass a test, availably solve laser to incise a focus to follow a problem, raised the control quality of system. The position detection system to be designed provide a solution for laser cutting.

  2. Applied Research on Medium and Low Power Level Dual-CO2-Laser Cutting Machine%中低功率双CO2激光切割机的开发与应用

    Institute of Scientific and Technical Information of China (English)

    甘家梁; 孙红安; 唐海昌

    2011-01-01

    Cutting principles of high-power single-CO2-laser cutting and low-power dual-CO2-laser cutting are discussed. Non-metallic materials such as wood die-boards are cut by using these two laser cutting techniques. The dependences of cutting depth and seam shape on laser power and cutting speed are analyzed. The results show that cutting wood die-boards with low-power dual-CO2-laser cutting has many advantages over high-power single-laser-head cutting in the manufacturing costs, operating costs, cutting precision and seam shape.%研究了大功率单CO2激光切割机和小功率双CO2激光切割机的切割原理,分析了在用这两种形式的激光切割机切割非金属材料木质模切板时,激光功率、切割速度与切割深度、切割的缝形缝宽之间的关系.试验结果表明,用中小功率双CO2激光切割机切割非金属木质板材,无论是设备的制造成本、运行成本,还是切割的精度和缝形缝宽,同用大功率单CO2激光头切割机相比有很多优势.

  3. Machinability evaluation of machinable ceramics with fuzzy theory

    Institute of Scientific and Technical Information of China (English)

    YU Ai-bing; ZHONG Li-jun; TAN Ye-fa

    2005-01-01

    The property parameters and machining output parameters were selected for machinability evaluation of machinable ceramics. Based on fuzzy evaluation theory, two-stage fuzzy evaluation approach was applied to consider these parameters. Two-stage fuzzy comprehensive evaluation model was proposed to evaluate machinability of machinable ceramic materials. Ce-ZrO2/CePO4 composites were fabricated and machined for evaluation of machinable ceramics. Material removal rates and specific normal grinding forces were measured. The parameters concerned with machinability were selected as alternative set. Five grades were chosen for the machinability evaluation of machnable ceramics. Machinability grades of machinable ceramics were determined through fuzzy operation. Ductile marks are observed on Ce-ZrO2/CePO4 machined surface. Five prepared Ce-ZrO2/CePO4 composites are classified as three machinability grades according to the fuzzy comprehensive evaluation results. The machinability grades of Ce-ZrO2/CePO4 composites are concerned with CePO4 content.

  4. MACHINE MOTION EQUATIONS

    Directory of Open Access Journals (Sweden)

    Florian Ion Tiberiu Petrescu

    2015-09-01

    Full Text Available This paper presents the dynamic, original, machine motion equations. The equation of motion of the machine that generates angular speed of the shaft (which varies with position and rotation speed is deduced by conservation kinetic energy of the machine. An additional variation of angular speed is added by multiplying by the coefficient dynamic D (generated by the forces out of mechanism and or by the forces generated by the elasticity of the system. Kinetic energy conservation shows angular speed variation (from the shaft with inertial masses, while the dynamic coefficient introduces the variation of w with forces acting in the mechanism. Deriving the first equation of motion of the machine one can obtain the second equation of motion dynamic. From the second equation of motion of the machine it determines the angular acceleration of the shaft. It shows the distribution of the forces on the mechanism to the internal combustion heat engines. Dynamic, the velocities can be distributed in the same way as forces. Practically, in the dynamic regimes, the velocities have the same timing as the forces. Calculations should be made for an engine with a single cylinder. Originally exemplification is done for a classic distribution mechanism, and then even the module B distribution mechanism of an Otto engine type.

  5. Dynamics of cyclic machines

    CERN Document Server

    Vulfson, Iosif

    2015-01-01

    This book focuses on modern methods of oscillation analysis in machines, including cyclic action mechanisms (linkages, cams, steppers, etc.). It presents schematization techniques and mathematical descriptions of oscillating systems, taking into account the variability of the parameters and nonlinearities, engineering evaluations of dynamic errors, and oscillation suppression methods. The majority of the book is devoted to the development of new methods of dynamic analysis and synthesis for cyclic machines that form regular oscillatory systems with multiple duplicate modules.  There are also sections examining aspects of general engineering interest (nonlinear dissipative forces, systems with non-stationary constraints, impacts and pseudo-impacts in clearances, etc.)  The examples in the book are based on the widely used results of theoretical and experimental studies as well as engineering calculations carried out in relation to machines used in the textile, light, polygraphic and other industries. Particu...

  6. Chatter and machine tools

    CERN Document Server

    Stone, Brian

    2014-01-01

    Focussing on occurrences of unstable vibrations, or Chatter, in machine tools, this book gives important insights into how to eliminate chatter with associated improvements in product quality, surface finish and tool wear. Covering a wide range of machining processes, including turning, drilling, milling and grinding, the author uses his research expertise and practical knowledge of vibration problems to provide solutions supported by experimental evidence of their effectiveness. In addition, this book contains links to supplementary animation programs that help readers to visualise the ideas detailed in the text. Advancing knowledge in chatter avoidance and suggesting areas for new innovations, Chatter and Machine Tools serves as a handbook for those desiring to achieve significant reductions in noise, longer tool and grinding wheel life and improved product finish.

  7. Machines and Metaphors

    Directory of Open Access Journals (Sweden)

    Ángel Martínez García-Posada

    2016-10-01

    Full Text Available The edition La ley del reloj. Arquitectura, máquinas y cultura moderna (Cátedra, Madrid, 2016 registers the useful paradox of the analogy between architecture and technique. Its author, the architect Eduardo Prieto, also a philosopher, professor and writer, acknowledges the obvious distance from machines to buildings, so great that it can only be solved using strange comparisons, since architecture does not move nor are the machines habitable, however throughout the book, from the origin of the metaphor of the machine, with clarity in his essay and enlightening erudition, he points out with certainty some concomitances of high interest, drawing throughout history a beautiful cartography of the fruitful encounter between organics and mechanics.

  8. Machine Learning Markets

    CERN Document Server

    Storkey, Amos

    2011-01-01

    Prediction markets show considerable promise for developing flexible mechanisms for machine learning. Here, machine learning markets for multivariate systems are defined, and a utility-based framework is established for their analysis. This differs from the usual approach of defining static betting functions. It is shown that such markets can implement model combination methods used in machine learning, such as product of expert and mixture of expert approaches as equilibrium pricing models, by varying agent utility functions. They can also implement models composed of local potentials, and message passing methods. Prediction markets also allow for more flexible combinations, by combining multiple different utility functions. Conversely, the market mechanisms implement inference in the relevant probabilistic models. This means that market mechanism can be utilized for implementing parallelized model building and inference for probabilistic modelling.

  9. Machine Learning for Security

    CERN Document Server

    CERN. Geneva

    2015-01-01

    Applied statistics, aka ‘Machine Learning’, offers a wealth of techniques for answering security questions. It’s a much hyped topic in the big data world, with many companies now providing machine learning as a service. This talk will demystify these techniques, explain the math, and demonstrate their application to security problems. The presentation will include how-to’s on classifying malware, looking into encrypted tunnels, and finding botnets in DNS data. About the speaker Josiah is a security researcher with HP TippingPoint DVLabs Research Group. He has over 15 years of professional software development experience. Josiah used to do AI, with work focused on graph theory, search, and deductive inference on large knowledge bases. As rules only get you so far, he moved from AI to using machine learning techniques identifying failure modes in email traffic. There followed digressions into clustered data storage and later integrated control systems. Current ...

  10. Machining strategy choice: performance VIEWER

    CERN Document Server

    Tapie, Laurent; Anselmetti, Bernard

    2009-01-01

    Nowadays high speed machining (HSM) machine tool combines productivity and part quality. So mould and die maker invested in HSM. Die and mould features are more and more complex shaped. Thus, it is difficult to choose the best machining strategy according to part shape. Geometrical analysis of machining features is not sufficient to make an optimal choice. Some research show that security, technical, functional and economical constrains must be taken into account to elaborate a machining strategy. During complex shape machining, production system limits induce feed rate decreases, thus loss of productivity, in some part areas. In this paper we propose to analyse these areas by estimating tool path quality. First we perform experiments on HSM machine tool to determine trajectory impact on machine tool behaviour. Then, we extract critical criteria and establish models of performance loss. Our work is focused on machine tool kinematical performance and numerical controller unit calculation capacity. We implement...

  11. Laser characterization with advanced digital signal processing

    DEFF Research Database (Denmark)

    Piels, Molly; Tafur Monroy, Idelfonso; Zibar, Darko

    2015-01-01

    The use of machine learning techniques to characterize lasers with low output power is reviewed. Optimized phase tracking algorithms that can produce accurate noise spectra are discussed, and a method for inferring the amplitude noise spectrum and rate equation model of the laser under test is pr...

  12. Pre-deformation for assembly performance of machine centers

    Science.gov (United States)

    Sun, Yongping; Wang, Delun; Dong, Huimin; Xue, Runiu; Yu, Shudong

    2014-05-01

    The current research of machine center accuracy in workspace mainly focuses on the poor geometric error subjected to thermal and gravity load while in operation, however, there are little researches focusing on the effect of machine center elastic deformations on workspace volume. Therefore, a method called pre-deformation for assembly performance is presented. This method is technically based on the characteristics of machine tool assembly and collaborative computer-aided engineering (CAE) analysis. The research goal is to enhance assembly performance, including straightness, positioning, and angular errors, to realize the precision of the machine tool design. A vertical machine center is taken as an example to illustrate the proposed method. The concept of travel error is defined to obtain the law of the guide surface. The machine center assembly performance is analyzed under cold condition and thermal balance condition to establish the function of pre-deformation. Then, the guide surface in normal direction is processed with the pre-deformation function, and the machine tool assembly performance is measured using a laser interferometer. The measuring results show that the straightness deviation of the Z component in the Y-direction is 158.9% of the allowable value primarily because of the gravity of the spindle head, and the straightness of the X and Y components is minimal. When the machine tool is processed in pre-deformation, the straightness of the Z axis moving component is reduced to 91.2%. This research proposes a pre-deformation machine center assembly method which has sufficient capacity to improving assembly accuracy of machine centers.

  13. Electrical machines diagnosis

    CERN Document Server

    Trigeassou, Jean-Claude

    2013-01-01

    Monitoring and diagnosis of electrical machine faults is a scientific and economic issue which is motivated by objectives for reliability and serviceability in electrical drives.This book provides a survey of the techniques used to detect the faults occurring in electrical drives: electrical, thermal and mechanical faults of the electrical machine, faults of the static converter and faults of the energy storage unit.Diagnosis of faults occurring in electrical drives is an essential part of a global monitoring system used to improve reliability and serviceability. This diagnosis is perf

  14. Refrigerating machine oil

    Energy Technology Data Exchange (ETDEWEB)

    Nozawa, K.

    1981-03-17

    Refrigerating machine oil to be filled in a sealed motorcompressor unit constituting a refrigerating cycle system including an electric refrigerator, an electric cold-storage box, a small-scaled electric refrigerating show-case, a small-scaled electric cold-storage show-case and the like, is arranged to have a specifically enhanced property, in which smaller initial driving power consumption of the sealed motor-compressor and easier supply of the predetermined amount of the refrigerating machine oil to the refrigerating system are both guaranteed even in a rather low environmental temperature condition.

  15. Machine shop basics

    CERN Document Server

    Miller, Rex

    2004-01-01

    Use the right tool the right wayHere, fully updated to include new machines and electronic/digital controls, is the ultimate guide to basic machine shop equipment and how to use it. Whether you're a professional machinist, an apprentice, a trade student, or a handy homeowner, this fully illustrated volume helps you define tools and use them properly and safely. It's packed with review questions for students, and loaded with answers you need on the job.Mark Richard Miller is a Professor and Chairman of the Industrial Technology Department at Texas A&M University in Kingsville, T

  16. Electrical machines & their applications

    CERN Document Server

    Hindmarsh, J

    1984-01-01

    A self-contained, comprehensive and unified treatment of electrical machines, including consideration of their control characteristics in both conventional and semiconductor switched circuits. This new edition has been expanded and updated to include material which reflects current thinking and practice. All references have been updated to conform to the latest national (BS) and international (IEC) recommendations and a new appendix has been added which deals more fully with the theory of permanent-magnets, recognising the growing importance of permanent-magnet machines. The text is so arra

  17. Clojure for machine learning

    CERN Document Server

    Wali, Akhil

    2014-01-01

    A book that brings out the strengths of Clojure programming that have to facilitate machine learning. Each topic is described in substantial detail, and examples and libraries in Clojure are also demonstrated.This book is intended for Clojure developers who want to explore the area of machine learning. Basic understanding of the Clojure programming language is required, but thorough acquaintance with the standard Clojure library or any libraries are not required. Familiarity with theoretical concepts and notation of mathematics and statistics would be an added advantage.

  18. Perpetual Motion Machine

    OpenAIRE

    D. Tsaousis

    2008-01-01

    Ever since the first century A.D. there have been relative descriptions of known devices as well as manufactures for the creation of perpetual motion machines. Although physics has led, with two thermodynamic laws, to the opinion that a perpetual motion machine is impossible to be manufactured, inventors of every age and educational level appear to claim that they have invented something «entirely new» or they have improved somebody else’s invention, which «will function henceforth perpetuall...

  19. Man - Machine Communication

    CERN Document Server

    Petersen, Peter; Nielsen, Henning

    1984-01-01

    This report describes a Man-to-Machine Communication module which together with a STAC can take care of all operator inputs from the touch-screen, tracker balls and mechanical buttons. The MMC module can also contain a G64 card which could be a GPIB driver but many other G64 cards could be used. The soft-ware services the input devices and makes the results accessible from the CAMAC bus. NODAL functions for the Man Machine Communication is implemented in the STAC and in the ICC.

  20. Machine Fault Signature Analysis

    Directory of Open Access Journals (Sweden)

    Pratesh Jayaswal

    2008-01-01

    Full Text Available The objective of this paper is to present recent developments in the field of machine fault signature analysis with particular regard to vibration analysis. The different types of faults that can be identified from the vibration signature analysis are, for example, gear fault, rolling contact bearing fault, journal bearing fault, flexible coupling faults, and electrical machine fault. It is not the intention of the authors to attempt to provide a detailed coverage of all the faults while detailed consideration is given to the subject of the rolling element bearing fault signature analysis.

  1. Analysis of laser micro drilled holes through aluminium for micro-manufacturing applications

    Science.gov (United States)

    Tunna, L.; O'Neill, W.; Khan, A.; Sutcliffe, C.

    2005-09-01

    Conventional laser machining of aluminium with long wavelength lasers has its inherent problems due to the high reflectivity of aluminium to laser radiation (Handbook of Optics, vol 1, 2nd ed. New York: McGraw-Hill; 1995). Laser processing at shorter wavelengths reduces the reflectivity of the workpiece to the incident laser radiation and can also reduce the dimensions of the obtainable machining geometries. This paper reviews the limiting factors in the micro machining of aluminium using a diode pumped solid state (DPSS) Nd:YAG laser operated at 1064, 532, and 355 nm. The geometries of the laser-machined samples were investigated using interferometric, and optical methods to assess how the processing fluence and wavelength will affect the obtainable precision for successful integration of the laser in a micromachining CAD/CAM system.

  2. Machine-vision based optofluidic cell sorting

    DEFF Research Database (Denmark)

    Glückstad, Jesper; Bañas, Andrew

    In contemporary life science there is an increasing emphasis on sorting rare disease-indicating cells within small dilute quantities such as in the confines of optofluidic lab-on-chip devices. Our approach to this is based on the use of optical forces to isolate red blood cells detected by advanc...... the available light and creating 2D or 3D beam distributions aimed at the positions of the detected cells. Furthermore, the beam shaping freedom provided by GPC can allow optimizations in the beam’s propagation and its interaction with the laser catapulted and sorted cells....... machine vision1. This approach is gentler, less invasive and more economical compared to conventional FACS-systems. As cells are less responsive to plastic or glass objects commonly used in the optical manipulation literature2, and since laser safety would be an issue in clinical use, we develop efficient...

  3. Buying a laser - Tips and pearls

    Directory of Open Access Journals (Sweden)

    Sanjeev J Aurangabadkar

    2014-01-01

    Meticulous planning of the type of machine, specifications, financial aspects, maintenance and warranties is important.It is wise to sign a contract or agreement between the buyer and seller before purchase of a laser which covers key aspects of installation, after sales service and maintenance of the machine.Adequate training is essential; understanding laser physics and laser-tissue interaction goes a long way in getting the best out of the machine.The credibility of the dealer and company should be ascertained in order to be assured of after-sales service.Buying used machines, sharing of equipment to offset high initial investments is a good option but even more care is required to ensure proper functioning and maintenance.

  4. Design of rotating electrical machines

    CERN Document Server

    Pyrhonen , Juha; Hrabovcova , Valeria

    2013-01-01

    In one complete volume, this essential reference presents an in-depth overview of the theoretical principles and techniques of electrical machine design. This timely new edition offers up-to-date theory and guidelines for the design of electrical machines, taking into account recent advances in permanent magnet machines as well as synchronous reluctance machines. New coverage includes: Brand new material on the ecological impact of the motors, covering the eco-design principles of rotating electrical machinesAn expanded section on the design of permanent magnet synchronous machines, now repo

  5. Machine speech and speaking about machines

    Energy Technology Data Exchange (ETDEWEB)

    Nye, A. [Univ. of Wisconsin, Whitewater, WI (United States)

    1996-12-31

    Current philosophy of language prides itself on scientific status. It boasts of being no longer contaminated with queer mental entities or idealist essences. It theorizes language as programmable variants of formal semantic systems, reimaginable either as the properly epiphenomenal machine functions of computer science or the properly material neural networks of physiology. Whether or not such models properly capture the physical workings of a living human brain is a question that scientists will have to answer. I, as a philosopher, come at the problem from another direction. Does contemporary philosophical semantics, in its dominant truth-theoretic and related versions, capture actual living human thought as it is experienced, or does it instead reflect, regardless of (perhaps dubious) scientific credentials, pathology of thought, a pathology with a disturbing social history.

  6. Hybrid machining processes perspectives on machining and finishing

    CERN Document Server

    Gupta, Kapil; Laubscher, R F

    2016-01-01

    This book describes various hybrid machining and finishing processes. It gives a critical review of the past work based on them as well as the current trends and research directions. For each hybrid machining process presented, the authors list the method of material removal, machining system, process variables and applications. This book provides a deep understanding of the need, application and mechanism of hybrid machining processes.

  7. LCLS Laser (in Polish)

    CERN Document Server

    Romaniuk, R S

    2013-01-01

    The most powerful now in the world, American X-ray laser LCLS (Linac Coherent Light Source), has been working as a research and user facility since 2009. It is further developed to LCLSII machine at the Stanford National Accelerator Laboratory SLAC in Menlo Park CA. In a certain sense, LCLS is a response to the EXFEL machine and a logical extension of LCLS. All these machines are light sources of the fifth generation. EXFELis expected to open user facility in 2016, at a cost of over 1 bil Euro. LCLS II, which design started in 2010, will be operational in 2017. The lasers LCLS, LCLS II and EXFEL use SASE and SEED methods to generate light and are powered by electron liniacs, LCLS by a wrm one, and EXFEL by a cold one. The liniacs have energies approaching 20 GeV, and are around 2 - 3 km in length. EXFEL liniac uses SRF TESLA cavity technology at 1,3GHz. A prototype of EXFEL was FLASH laser. SLAC Laboratory uses effectively over 50 years experience in research, building and exploitation of linear electron acce...

  8. Cybernetic anthropomorphic machine systems

    Science.gov (United States)

    Gray, W. E.

    1974-01-01

    Functional descriptions are provided for a number of cybernetic man machine systems that augment the capacity of normal human beings in the areas of strength, reach or physical size, and environmental interaction, and that are also applicable to aiding the neurologically handicapped. Teleoperators, computer control, exoskeletal devices, quadruped vehicles, space maintenance systems, and communications equipment are considered.

  9. ARM : abstract rewriting machine

    NARCIS (Netherlands)

    J.F.T. Kamperman; H.R. Walters (Pum)

    1993-01-01

    textabstractTerm rewriting is frequently used as implementation technique for algebraic specifications. In this paper we present the abstract term rewriting machine (ARM), which has an extremely compact instruction set and imposes no restrictions on the implemented TRSs. Apart from standard

  10. A "Living" Machine

    Institute of Scientific and Technical Information of China (English)

    N.R.Bogatyrev

    2004-01-01

    Biomimetics (or bionics) is the engineering discipline that constructs artificial systems using biological principles. The ideal final result in biomimetics is to create a living machine. But what are the desirable and non-desirable properties of biomimetic product? Where can natural prototypes be found? How can technical solutions be transferred from nature to technology? Can we use living nature like LEGO bricks for construction our machines? How can biology help us? What is a living machine? In biomimetic practice only some "part" (organ, part of organ, tissue) of the observed whole organism is utilized. A possible template for future super-organism extension for biomimetic methods might be drawn from experiments in holistic ecological agriculture (ecological design, permaculture, ecological engineering, etc. ). The necessary translation of these rules to practical action can be achieved with the Russian Theory of Inventive Problem Solving (TRIZ), specifically adjusted to biology. Thus, permaculture, reinforced by a TRIZ conceptual framework, might provide the basis for Super-Organismic Bionics, which is hypothesized as necessary for effective ecological engineering. This hypothesis is supported by a case study-the design of a sustainable artificial nature reserve for wild pollinators as a living machine.

  11. Of machines and men ...

    CERN Multimedia

    CERN; Daniel Boileau

    1990-01-01

    Engineering and construction at LEP. Committed work and physicists motivation to work on this type of machine. With Guido Altarelli Theory Division Physicist, Ugo Amaldi Delphi Experiment Spokesman, Oscar Barbalat Head of Industry and Technology Liaison Office, Jonathan Ellis Head of Theory Division.

  12. Technology Time Machine 2012

    DEFF Research Database (Denmark)

    Lehner, Wolfgang; Fettweis, Gerhard; Fitzek, Frank

    2013-01-01

    The IEEE Technology Time Machine (TTM) is a unique event for industry leaders, academics, and decision making government officials who direct R&D activities, plan research programs or manage portfolios of research activities. This report covers the main topics of the 2nd Symposium of future...

  13. Training Restricted Boltzmann Machines

    DEFF Research Database (Denmark)

    Fischer, Asja

    Restricted Boltzmann machines (RBMs) are probabilistic graphical models that can also be interpreted as stochastic neural networks. Training RBMs is known to be challenging. Computing the likelihood of the model parameters or its gradient is in general computationally intensive. Thus, training...

  14. Electrical Discharge Machining.

    Science.gov (United States)

    Montgomery, C. M.

    The manual is for use by students learning electrical discharge machining (EDM). It consists of eight units divided into several lessons, each designed to meet one of the stated objectives for the unit. The units deal with: introduction to and advantages of EDM, the EDM process, basic components of EDM, reaction between forming tool and workpiece,…

  15. The Answer Machine.

    Science.gov (United States)

    Feldman, Susan

    2000-01-01

    Discusses information retrieval systems and the need to have them adapt to user needs, integrate information in any format, reveal patterns and trends in information, and answer questions. Topics include statistics and probability; natural language processing; intelligent agents; concept mapping; machine-aided indexing; text mining; filtering;…

  16. Massively collaborative machine learning

    NARCIS (Netherlands)

    Rijn, van J.N.

    2016-01-01

    Many scientists are focussed on building models. We nearly process all information we perceive to a model. There are many techniques that enable computers to build models as well. The field of research that develops such techniques is called Machine Learning. Many research is devoted to develop comp

  17. Recent Advances on Permanent Magnet Machines

    Institute of Scientific and Technical Information of China (English)

    诸自强

    2012-01-01

    This paper overviews advances on permanent magnet(PM) brushless machines over last 30 years,with particular reference to new and novel machine topologies.These include current states and trends for surface-mounted and interior PM machines,electrically and mechanically adjusted variable flux PM machines including memory machine,hybrid PM machines which uniquely integrate PM technology into induction machines,switched and synchronous reluctance machines and wound field machines,Halbach PM machines,dual-rotor PM machines,and magnetically geared PM machines,etc.The paper highlights their features and applications to various market sectors.

  18. Fabrication of titanium implant-retained restorations with nontraditional machining techniques.

    Science.gov (United States)

    Schmitt, S M; Chance, D A

    1995-01-01

    Traditional laboratory techniques are being supplemented by modern precision technologies to solve complex restorative problems. Electrical discharge machining combined with laser scanning and computer aided design-computer aided manufacturing can create very precise restorations without the lost wax method. A laser scanner is used to create a three-dimensional polyline data model that can then be converted into a stereolithography file format for output to a stereolithography apparatus or other rapid prototyping device. A stereolithography-generated model is used to create an electric discharge machining electrode via copper electroforming. This electrode is used to machine dental restorations from an ingot of titanium, bypassing the conventional lost wax casting process. Retaining screw access holes are machined using conventional drilling procedures, but could be accomplished with electric discharge machining if desired. Other rapid prototyping technologies are briefly discussed.

  19. Analysis on the cutting process parameters of the high power laser cutting machine%大功率激光切割机切割工艺参数分析

    Institute of Scientific and Technical Information of China (English)

    袁小会; 蔡逸飞

    2012-01-01

    初步探讨了影响激光切割碳素结构钢板切割质量的因素,在其他参数不变的情况下,最小打孔功率和最小无“挂渣”切割功率随着板材厚度的增加而增大;切缝断面粗糙度随着切割气体压力和切割速度先减小后增大.%The impact factors of laser cutting quality on carbon steel plate have been studied. In the conditions of other parameters unchanged, the minimum laser output power for punching and properly cutting increase with the carbon steel plate thickness. Slotted section roughness increases then decreases with the cutting gas pressure and cutting speed increasing.

  20. Laser technology in solar absorber manufacturing; Laser punktet

    Energy Technology Data Exchange (ETDEWEB)

    Berner, Joachim

    2009-12-07

    No other solar collector manufacturing stage is as fully automatic as absorber fabrication. Laser welding systems are well established in the market. In addition to welding machines, some manufacturers are also offering complete assembly lines for solar collector production. SONNE WIND and WAeRME presents technologies and manufacturers. (orig./AKB)

  1. Motherhood and the Machine

    Directory of Open Access Journals (Sweden)

    Miglena Nikolchina

    2014-12-01

    Full Text Available In her conceptualization of the human as defined by the capacity for revolt Kristeva unavoidably touches upon issues of robotization, technology, and the virtual. The concepts of animal and machine, however, although they do appear occasionally and in important ways, are never at the focus of her inquiries and are absent in her “New Forms of Revolt.” Yet these two concepts to a large extent define the field of contemporary philosophical debates of the human giving rise to three major theoretical orientations. On the one hand, there is the trend which tries to come to terms with technological novelties and the merging of human and machine that they imply. This trend unfolds under the rubric of “transhuman” or “posthuman” and of the “enhancement” of man. The second trend predominates in animal studies. Mostly in an ethical perspective but also ontologically, this trend, to which Derrida’s later writing made a significant contribution, questions the idea of the “human exception” and the rigorous distinction between man and animal on which this exception rests. While apparently antagonistic, both trends align the human with the animal and oppose it to technology. The third trend collapses the distinctions on which the previous two rely through the lens of biopolitics: drawing on Heidegger, Kojève, and Foucault, it regards contemporary technological transformations as amounting to the animalization of man.  The human disappears in the animal, in the machine, or in the indistinguishability of the two, confirming what Agamben has described as the inoperativeness of the anthropological machine. The present text turns to Kristeva’s conceptions of motherhood and revolt as introducing a powerful inflection in this tripartite field. Remarkably, it is precisely new sagas of rebellious machines like Battlestar “Galactica” that foreground the relevance of Kristeva’s approach.

  2. Femtosecond Laser Interaction with Energetic Materials

    Energy Technology Data Exchange (ETDEWEB)

    Roos, E; Benterou, J; Lee, R; Roeske, F; Stuart, B

    2002-03-25

    Femtosecond laser ablation shows promise in machining energetic materials into desired shapes with minimal thermal and mechanical effects to the remaining material. We will discuss the physical effects associated with machining energetic materials and assemblies containing energetic materials, based on experimental results. Interaction of ultra-short laser pulses with matter will produce high temperature plasma at high-pressure which results in the ablation of material. In the case of energetic material, which includes high explosives, propellants and pyrotechnics, this ablation process must be accomplished without coupling energy into the energetic material. Experiments were conducted in order to characterize and better understand the phenomena of femtosecond laser pulse ablation on a variety of explosives and propellants. Experimental data will be presented for laser fluence thresholds, machining rates, cutting depths and surface quality of the cuts.

  3. Laser processing of ceramics for microelectronics manufacturing

    Science.gov (United States)

    Sposili, Robert S.; Bovatsek, James; Patel, Rajesh

    2017-03-01

    Ceramic materials are used extensively in the microelectronics, semiconductor, and LED lighting industries because of their electrically insulating and thermally conductive properties, as well as for their high-temperature-service capabilities. However, their brittleness presents significant challenges for conventional machining processes. In this paper we report on a series of experiments that demonstrate and characterize the efficacy of pulsed nanosecond UV and green lasers in machining ceramics commonly used in microelectronics manufacturing, such as aluminum oxide (alumina) and aluminum nitride. With a series of laser pocket milling experiments, fundamental volume ablation rate and ablation efficiency data were generated. In addition, techniques for various industrial machining processes, such as shallow scribing and deep scribing, were developed and demonstrated. We demonstrate that lasers with higher average powers offer higher processing rates with the one exception of deep scribes in aluminum nitride, where a lower average power but higher pulse energy source outperformed a higher average power laser.

  4. Machine learning in image steganalysis

    CERN Document Server

    Schaathun, Hans Georg

    2012-01-01

    "The only book to look at steganalysis from the perspective of machine learning theory, and to apply the common technique of machine learning to the particular field of steganalysis; ideal for people working in both disciplines"--

  5. New Applications of Learning Machines

    DEFF Research Database (Denmark)

    Larsen, Jan

    * Machine learning framework for sound search * Genre classification * Music separation * MIMO channel estimation and symbol detection......* Machine learning framework for sound search * Genre classification * Music separation * MIMO channel estimation and symbol detection...

  6. New Applications of Learning Machines

    DEFF Research Database (Denmark)

    Larsen, Jan

    * Machine learning framework for sound search * Genre classification * Music separation * MIMO channel estimation and symbol detection......* Machine learning framework for sound search * Genre classification * Music separation * MIMO channel estimation and symbol detection...

  7. Hinged Shields for Machine Tools

    Science.gov (United States)

    Lallande, J. B.; Poland, W. W.; Tull, S.

    1985-01-01

    Flaps guard against flying chips, but fold away for tool setup. Clear plastic shield in position to intercept flying chips from machine tool and retracted to give operator access to workpiece. Machine shops readily make such shields for own use.

  8. Design of Sugarcane Peeling Machine

    Directory of Open Access Journals (Sweden)

    Ge Xinfeng

    2015-02-01

    Full Text Available In order to solve the problem that appeared in hand peeling sugarcane, the sugarcane peeling machine is designed, the sugarcane peeling machine includes motor, groove wheel, cutting room, slider crank mechanism, reducer (including belt drive, chain drive and so on. The designed sugarcane peeling machine is simulated, the results show that the sugarcane peeling machine can peel sugarcane successfully with convenient, fast and uniform.

  9. Automatically-Programed Machine Tools

    Science.gov (United States)

    Purves, L.; Clerman, N.

    1985-01-01

    Software produces cutter location files for numerically-controlled machine tools. APT, acronym for Automatically Programed Tools, is among most widely used software systems for computerized machine tools. APT developed for explicit purpose of providing effective software system for programing NC machine tools. APT system includes specification of APT programing language and language processor, which executes APT statements and generates NC machine-tool motions specified by APT statements.

  10. Automatically-Programed Machine Tools

    Science.gov (United States)

    Purves, L.; Clerman, N.

    1985-01-01

    Software produces cutter location files for numerically-controlled machine tools. APT, acronym for Automatically Programed Tools, is among most widely used software systems for computerized machine tools. APT developed for explicit purpose of providing effective software system for programing NC machine tools. APT system includes specification of APT programing language and language processor, which executes APT statements and generates NC machine-tool motions specified by APT statements.

  11. Feature Recognition for Virtual Machining

    OpenAIRE

    Xú, Shixin; Anwer, Nabil; Qiao, Lihong

    2014-01-01

    International audience; Virtual machining uses software tools to simulate machining processes in virtual environments ahead of actual production. This paper proposes that feature recognition techniques can be applied in the course of virtual machining, such as identifying some process problems, and presenting corresponding correcting advices. By comparing with the original CAD model, form errors of the machining features can be found. And then corrections are suggested to process designers. T...

  12. Programmable Laser-Assisted Surface Microfabrication on a Poly(Vinyl Alcohol)-Coated Glass Chip with Self-Changing Cell Adhesivity for Heterotypic Cell Patterning.

    Science.gov (United States)

    Li, Yi-Chen; Lin, Meng-Wei; Yen, Meng-Hua; Fan, Sabrina Mai-Yi; Wu, June-Tai; Young, Tai-Horng; Cheng, Ji-Yen; Lin, Sung-Jan

    2015-10-14

    Organs are composed of heterotypic cells with patterned architecture that enables intercellular interaction to perform specific functions. In tissue engineering, the ability to pattern heterotypic cells into desired arrangement will allow us to model complex tissues in vitro and to create tissue equivalents for regeneration. This study was aimed at developing a method for fast heterotypic cell patterning with controllable topological manipulation on a glass chip. We found that poly(vinyl alcohol)-coated glass showed a biphasic change in adhesivity to cells in vitro: low adhesivity in the first 24 h and higher adhesivity at later hours due to increased serum protein adsorption. Combining programmable CO2 laser ablation to remove poly(vinyl alcohol) and glass, we were able to create arrays of adhesive microwells of adjustable patterns. We tested whether controllable patterns of epithelial-mesenchymal interaction could be created. When skin dermal papilla cells and fibroblasts were seeded respectively 24 h apart, we were able to pattern these two cells into aggregates of dermal papilla cells in arrays of microwells in a background of fibroblasts sheet. Seeded later, keratinocytes attached to these mesenchymal cells. Keratinocytes contacting dermal papilla cells started to differentiate toward a hair follicle fate, demonstrating patternable epithelial-mesenchymal interaction. This method allows fast adjustable heterotypic cell patterning and surface topology control and can be applied to the investigation of heterotypic cellular interaction and creation of tissue equivalent in vitro.

  13. Development of a Power Supply Control System for Laser Cutting Machine%一种激光切割机驱动电源控制系统设计

    Institute of Scientific and Technical Information of China (English)

    姜宇; 张承瑞; 张金泽

    2012-01-01

    提出了一种新的激光切割机的电源控制系统设计方案,该方案融入了FPGA技术,采用意法半导体公司的ARM为控制核心,优化了电路设计,增强系统整体的可靠性,从而实现了高稳定度的激光切割机电源驱动控制.采用MATLAB对参数限制条件进行拟合,简化了ARM程序.通过巴特沃斯型低通滤器对ARM输出的电压进行滤波,更好地抑制高频信号干扰,提高系统的精度.利用旋转编码器实现对参数的输入、液晶屏的显示以及整机的控制,操作简便.实际应用表明,电源控制系统具有智能化程度高、抗干扰能力强、精度高、运行稳定、操作方便、人机界面友好等优点.%The cutting-force coefficient is one of the important parameters in assessing the cutting-force of machine. The force and the elastic deformation in the processing of thin-walled workpiece machining were analyzed, and the theoretical model based on cutting-force coefficient was established. According to the force balance principle, the workpiece surface errors measured by the three-coordinate measured machine were distributed to the elastic deformation of the workpiece and tool errors. The errors were brought into the theoretical model for solving the cutting force coefficients by MATLAB tools. And cutting force predicted by the model were compared with the cutting force measured. As a result, cutting force predicted by the model fit the waveform, and close to the average of the measured cutting force.

  14. MACHINE PROTECTION FOR HIGH AVERAGE CURRENT LINACS

    Energy Technology Data Exchange (ETDEWEB)

    Jordan, Kevin; Allison, Trent; Evans, Richard; Coleman, James; Grippo, Albert

    2003-05-01

    A fully integrated Machine Protection System (MPS) is critical to efficient commissioning and safe operation of all high current accelerators. The Jefferson Lab FEL [1,2] has multiple electron beam paths and many different types of diagnostic insertion devices. The MPS [3] needs to monitor both the status of these devices and the magnet settings which define the beam path. The matrix of these devices and beam paths are programmed into gate arrays, the output of the matrix is an allowable maximum average power limit. This power limit is enforced by the drive laser for the photocathode gun. The Beam Loss Monitors (BLMs), RF status, and laser safety system status are also inputs to the control matrix. There are 8 Machine Modes (electron path) and 8 Beam Modes (average power limits) that define the safe operating limits for the FEL. Combinations outside of this matrix are unsafe and the beam is inhibited. The power limits range from no beam to 2 megawatts of electron beam power.

  15. Material Processing Laser Systems For Manufacturing

    Science.gov (United States)

    Taeusch, David R.; Ruselowski, John M.

    1986-11-01

    Raycon Corporation is a builder of quality machine tools. Combining this with applications expertise to produce high technology production machinery systems using EDM, lasers and other processing methods to solve our customers' production problems is our product. The company has several standard laser machine systems which can be constructed from standard building blocks. The number of axes and travel, the controller requirements, and the required laser type, size and manufacturer are discussed with our customers, and the system to meet their needs is decided upon. These requirements are then built into a processing system for manufacturing use. Several of these systems which are in the field are described, and their purposes and how they accomplish their task are explained. Also, types of YAG and C02 lasers available are described and their optimum use explained. Some specific examples of type versus applications are: YAG low-divergence lasers for trepanning heat-resistant alloys for jet engine turbines; YAG oscillator-amplifier lasers for percussion drilling of cooling holes in jet engine turbine blades; and several special laser machine systems for processing automotive parts are discussed. A few words on laser safety are included to allay some common fears concerning the use of laser technology in the factory environment.

  16. The Neural Support Vector Machine

    NARCIS (Netherlands)

    Wiering, Marco; van der Ree, Michiel; Embrechts, Mark; Stollenga, Marijn; Meijster, Arnold; Nolte, A; Schomaker, Lambertus

    2013-01-01

    This paper describes a new machine learning algorithm for regression and dimensionality reduction tasks. The Neural Support Vector Machine (NSVM) is a hybrid learning algorithm consisting of neural networks and support vector machines (SVMs). The output of the NSVM is given by SVMs that take a

  17. The Neural Support Vector Machine

    NARCIS (Netherlands)

    Wiering, Marco; van der Ree, Michiel; Embrechts, Mark; Stollenga, Marijn; Meijster, Arnold; Nolte, A; Schomaker, Lambertus

    2013-01-01

    This paper describes a new machine learning algorithm for regression and dimensionality reduction tasks. The Neural Support Vector Machine (NSVM) is a hybrid learning algorithm consisting of neural networks and support vector machines (SVMs). The output of the NSVM is given by SVMs that take a centr

  18. Prediction of Machine Tool Condition Using Support Vector Machine

    Science.gov (United States)

    Wang, Peigong; Meng, Qingfeng; Zhao, Jian; Li, Junjie; Wang, Xiufeng

    2011-07-01

    Condition monitoring and predicting of CNC machine tools are investigated in this paper. Considering the CNC machine tools are often small numbers of samples, a condition predicting method for CNC machine tools based on support vector machines (SVMs) is proposed, then one-step and multi-step condition prediction models are constructed. The support vector machines prediction models are used to predict the trends of working condition of a certain type of CNC worm wheel and gear grinding machine by applying sequence data of vibration signal, which is collected during machine processing. And the relationship between different eigenvalue in CNC vibration signal and machining quality is discussed. The test result shows that the trend of vibration signal Peak-to-peak value in surface normal direction is most relevant to the trend of surface roughness value. In trends prediction of working condition, support vector machine has higher prediction accuracy both in the short term ('One-step') and long term (multi-step) prediction compared to autoregressive (AR) model and the RBF neural network. Experimental results show that it is feasible to apply support vector machine to CNC machine tool condition prediction.

  19. A Boltzmann machine for the organization of intelligent machines

    Science.gov (United States)

    Moed, Michael C.; Saridis, George N.

    1989-01-01

    In the present technological society, there is a major need to build machines that would execute intelligent tasks operating in uncertain environments with minimum interaction with a human operator. Although some designers have built smart robots, utilizing heuristic ideas, there is no systematic approach to design such machines in an engineering manner. Recently, cross-disciplinary research from the fields of computers, systems AI and information theory has served to set the foundations of the emerging area of the design of intelligent machines. Since 1977 Saridis has been developing an approach, defined as Hierarchical Intelligent Control, designed to organize, coordinate and execute anthropomorphic tasks by a machine with minimum interaction with a human operator. This approach utilizes analytical (probabilistic) models to describe and control the various functions of the intelligent machine structured by the intuitively defined principle of Increasing Precision with Decreasing Intelligence (IPDI) (Saridis 1979). This principle, even though resembles the managerial structure of organizational systems (Levis 1988), has been derived on an analytic basis by Saridis (1988). The purpose is to derive analytically a Boltzmann machine suitable for optimal connection of nodes in a neural net (Fahlman, Hinton, Sejnowski, 1985). Then this machine will serve to search for the optimal design of the organization level of an intelligent machine. In order to accomplish this, some mathematical theory of the intelligent machines will be first outlined. Then some definitions of the variables associated with the principle, like machine intelligence, machine knowledge, and precision will be made (Saridis, Valavanis 1988). Then a procedure to establish the Boltzmann machine on an analytic basis will be presented and illustrated by an example in designing the organization level of an Intelligent Machine. A new search technique, the Modified Genetic Algorithm, is presented and proved

  20. Engineering molecular machines

    Science.gov (United States)

    Erman, Burak

    2016-04-01

    Biological molecular motors use chemical energy, mostly in the form of ATP hydrolysis, and convert it to mechanical energy. Correlated thermal fluctuations are essential for the function of a molecular machine and it is the hydrolysis of ATP that modifies the correlated fluctuations of the system. Correlations are consequences of the molecular architecture of the protein. The idea that synthetic molecular machines may be constructed by designing the proper molecular architecture is challenging. In their paper, Sarkar et al (2016 New J. Phys. 18 043006) propose a synthetic molecular motor based on the coarse grained elastic network model of proteins and show by numerical simulations that motor function is realized, ranging from deterministic to thermal, depending on temperature. This work opens up a new range of possibilities of molecular architecture based engine design.

  1. Boosting Support Vector Machines

    Directory of Open Access Journals (Sweden)

    Elkin Eduardo García Díaz

    2006-11-01

    Full Text Available En este artículo, se presenta un algoritmo de clasificación binaria basado en Support Vector Machines (Máquinas de Vectores de Soporte que combinado apropiadamente con técnicas de Boosting consigue un mejor desempeño en cuanto a tiempo de entrenamiento y conserva características similares de generalización con un modelo de igual complejidad pero de representación más compacta./ In this paper we present an algorithm of binary classification based on Support Vector Machines. It is combined with a modified Boosting algorithm. It run faster than the original SVM algorithm with a similar generalization error and equal complexity model but it has more compact representation.

  2. Quo vadis, Intelligent Machine?

    Directory of Open Access Journals (Sweden)

    Rosemarie Velik

    2010-09-01

    Full Text Available Artificial Intelligence (AI is a branch of computer science concerned with making computers behave like humans. At least this was the original idea. However, it turned out that this is no task easy to be solved. This article aims to give a comprehensible review on the last 60 years of artificial intelligence taking a philosophical viewpoint. It is outlined what happened so far in AI, what is currently going on in this research area, and what can be expected in future. The goal is to mediate an understanding for the developments and changes in thinking in course of time about how to achieve machine intelligence. The clear message is that AI has to join forces with neuroscience and other brain disciplines in order to make a step towards the development of truly intelligent machines.

  3. Introduction to Machine Protection

    CERN Document Server

    Schmidt, R

    2016-01-01

    Protection of accelerator equipment is as old as accelerator technology and was for many years related to high-power equipment. Examples are the protection of powering equipment from overheating (magnets, power converters, high-current cables), of superconducting magnets from damage after a quench and of klystrons. The protection of equipment from beam accidents is more recent, although there was one paper that discussed beam-induced damage for the SLAC linac (Stanford Linear Accelerator Center) as early as in 1967. It is related to the increasing beam power of high-power proton accelerators, to the emission of synchrotron light by electron-positron accelerators and to the increase of energy stored in the beam. Designing a machine protection system requires an excellent understanding of accelerator physics and operation to anticipate possible failures that could lead to damage. Machine protection includes beam and equipment monitoring, a system to safely stop beam operation (e.g. dumping the beam or stopping ...

  4. Technological requirements of profile machining

    Institute of Scientific and Technical Information of China (English)

    PARK Sangchul; CHUNG Yunchan

    2006-01-01

    The term ‘profile machining’is used to refer to the milling of vertical surfaces described by profile curves. Profile machining requires higher precision (1/1000 mm) than regular 3D machining (1/100 mm) with the erosion of sharp vertices should being especially avoided. Although, profile machining is very essential for making trimming and flangedies, it seldom brought into focus. This paper addresses the technological requirements of profile machining including machining width and depth control,minimizing toolware, and protecting sharp vertices. Issues of controller alarms are also addressed.

  5. Future database machine architectures

    OpenAIRE

    Hsiao, David K.

    1984-01-01

    There are many software database management systems available on many general-purpose computers ranging from micros to super-mainframes. Database machines as backened computers can offload the database management work from the mainframe so that we can retain the same mainframe longer. However, the database backend must also demonstrate lower cost, higher performance, and newer functionality. Some of the fundamental architecture issues in the design of high-performance and great-capacity datab...

  6. Machine Learning at Scale

    OpenAIRE

    Izrailev, Sergei; Stanley, Jeremy M.

    2014-01-01

    It takes skill to build a meaningful predictive model even with the abundance of implementations of modern machine learning algorithms and readily available computing resources. Building a model becomes challenging if hundreds of terabytes of data need to be processed to produce the training data set. In a digital advertising technology setting, we are faced with the need to build thousands of such models that predict user behavior and power advertising campaigns in a 24/7 chaotic real-time p...

  7. Cost of photochemical machining

    OpenAIRE

    Roy, Rajkumar; Allen, David; Zamora, Oscar

    2004-01-01

    Photochemical machining (PCM), also known as photoetching, photofabrication or photochemical milling, is a non-traditional manufacturing method based on the combination of photoresist imaging and chemical etching. PCM uses techniques similar to those employed for the production of printed circuit boards and silicon integrated circuits. The PCM industry plays a valuable worldwide role in the production of metal precision parts and decorative items. Parts produced by PCM are t...

  8. Austempered Ductile Iron Machining

    Science.gov (United States)

    Pilc, Jozef; Šajgalík, Michal; Holubják, Jozef; Piešová, Marianna; Zaušková, Lucia; Babík, Ondrej; Kuždák, Viktor; Rákoci, Jozef

    2015-12-01

    This article deals with the machining of cast iron. In industrial practice, Austempered Ductile Iron began to be used relatively recently. ADI is ductile iron that has gone through austempering to get improved properties, among which we can include strength, wear resistance or noise damping. This specific material is defined also by other properties, such as high elasticity, ductility and endurance against tenigue, which are the properties, that considerably make the tooling characteristic worse.

  9. Quantum Virtual Machine (QVM)

    Energy Technology Data Exchange (ETDEWEB)

    2016-11-18

    There is a lack of state-of-the-art HPC simulation tools for simulating general quantum computing. Furthermore, there are no real software tools that integrate current quantum computers into existing classical HPC workflows. This product, the Quantum Virtual Machine (QVM), solves this problem by providing an extensible framework for pluggable virtual, or physical, quantum processing units (QPUs). It enables the execution of low level quantum assembly codes and returns the results of such executions.

  10. Agent Based Computing Machine

    Science.gov (United States)

    2005-12-09

    be used in Phase 2 to accomplish the following enhancements. Due to the speed and support of MPI for C/C++ on Beowulf clusters , these languages could...1.7 ABC Machine Formal Definition 24 1.8 Computational Analysis 31 1.9 Programming Concepts 34 1.10 Cluster Mapping 38 1.11 Phase 1 Results 43 2...options for hardware implementation are explored including an emulation with a high performance cluster , a high performance silicon chip and the

  11. Magnetic Electrochemical Finishing Machining

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    How to improve the finishing efficiency and surface roughness have been all along the objective of research in electrochemical polishing. However, the research activity, i.e. during electrochemical polishing, directly introduce the magnetic field to study how the magnetic field influences on the finishing efficiency, quality and the electrochemical process in the field of finishing machining technology, is insufficient. When introducing additional magnetic field in the traditional electrochemical pol...

  12. FMS precision machining

    Energy Technology Data Exchange (ETDEWEB)

    Burnham, M.W.

    1980-01-01

    In evaluating the technical obstacles and accuracy limits to producing a Precision Flexible Manufacturing System, a current system is subjected to an error budget analysis. It is noted that to make complex part geometries with tolerances in the lower thousandths range, machining to tenths is required for process control. Actual parts made to tenths are illustrated, along with a discussion of the requirements for automation and for process control.

  13. Machine on Trial

    Science.gov (United States)

    2012-06-01

    front of the Judge, how did we come to justify the ethical use of such a machine? The Judge called for a recess so that he could further educate ...commerce, where money would change hands, or for the purposes of controlling critical systems.”29 The initial group that set up the ARPANET did not... EBook of Fundamental Principals of the Metaphysic of Morals, May, 2004 [ EBook #5682 translated by Thomas Kingsmill Abbott, 12. http://manybooks.net

  14. Production excimer laser equipment overview

    Science.gov (United States)

    Sercel, Jeffrey P.

    1993-04-01

    Excimer lasers were commercialized in the late 1970's. The laser community thought that by the early 1980's these UV lasers would enjoy a fruitful industrial market position. CO2 and solid state lasers required almost two decades to be fully accepted as industrial machine while the excimer laser was expected to be a fast learner benefiting from the learning curve of its big brothers. In retrospect, early excimer lasers had a bad reputation for being complicated, expensive and frequently out of commission. By the late 1980's a few excimer laser manufacturers had engineered the problems to acceptable levels for successful pilot lines and small scale manufacturing to begin. At this time, the real industrial learning curves began as engineers worked to refine many subsystems and support technologies. Today, excimer lasers are being used as true industrial lasers. They have a bright future with numerous and diverse market opportunities. This paper is an overview of the technologies proven to be successful in adapting modern excimer lasers to successful full production situations.

  15. Electrochemical Discharge Machining Process

    Directory of Open Access Journals (Sweden)

    Anjali V. Kulkarni

    2007-09-01

    Full Text Available Electrochemical discharge machining process is evolving as a promising micromachiningprocess. The experimental investigations in the present work substantiate this trend. In the presentwork, in situ, synchronised, transient temperature and current measurements have been carriedout. The need for the transient measurements arose due to the time-varying nature of the dischargeformation and time varying circuit current. Synchronised and transient measurements revealedthe discrete nature of the process. It also helped in formulating the basic mechanism for thedischarge formation and the material removal in the process. Temperature profile on workpieceand in electrochemical discharge machining cell is experimentally measured using pyrometer,and two varieties of K-type thermocouples. Surface topography of the discharge-affected zoneson the workpiece has been carried out using scanning electron microscope. Measurements andsurface topographical studies reveal the potential use of this process for machining in micronregime. With careful experimental set-up design, suitable supply voltage and its polarity, theprocess can be applied for both micromachining and micro-deposition. It can be extended formachining and or deposition of wide range of materials.

  16. Introduction: Minds, Bodies, Machines

    Directory of Open Access Journals (Sweden)

    Deirdre Coleman

    2008-10-01

    Full Text Available This issue of 19 brings together a selection of essays from an interdisciplinary conference on 'Minds, Bodies, Machines' convened last year by Birkbeck's Centre for Nineteenth-Century Studies, University of London, in partnership with the English programme, University of Melbourne and software developers Constraint Technologies International (CTI. The conference explored the relationship between minds, bodies and machines in the long nineteenth century, with a view to understanding the history of our technology-driven, post-human visions. It is in the nineteenth century that the relationship between the human and the machine under post-industrial capitalism becomes a pervasive theme. From Blake on the mills of the mind by which we are enslaved, to Carlyle's and Arnold's denunciation of the machinery of modern life, from Dickens's sooty fictional locomotive Mr Pancks, who 'snorted and sniffed and puffed and blew, like a little labouring steam-engine', and 'shot out […]cinders of principles, as if it were done by mechanical revolvency', to the alienated historical body of the late-nineteenth-century factory worker under Taylorization, whose movements and gestures were timed, regulated and rationalised to maximize efficiency; we find a cultural preoccupation with the mechanisation of the nineteenth-century human body that uncannily resonates with modern dreams and anxieties around technologies of the human.

  17. Machine Learning in Medicine.

    Science.gov (United States)

    Deo, Rahul C

    2015-11-17

    Spurred by advances in processing power, memory, storage, and an unprecedented wealth of data, computers are being asked to tackle increasingly complex learning tasks, often with astonishing success. Computers have now mastered a popular variant of poker, learned the laws of physics from experimental data, and become experts in video games - tasks that would have been deemed impossible not too long ago. In parallel, the number of companies centered on applying complex data analysis to varying industries has exploded, and it is thus unsurprising that some analytic companies are turning attention to problems in health care. The purpose of this review is to explore what problems in medicine might benefit from such learning approaches and use examples from the literature to introduce basic concepts in machine learning. It is important to note that seemingly large enough medical data sets and adequate learning algorithms have been available for many decades, and yet, although there are thousands of papers applying machine learning algorithms to medical data, very few have contributed meaningfully to clinical care. This lack of impact stands in stark contrast to the enormous relevance of machine learning to many other industries. Thus, part of my effort will be to identify what obstacles there may be to changing the practice of medicine through statistical learning approaches, and discuss how these might be overcome.

  18. Behind the machines

    CERN Document Server

    Laëtitia Pedroso

    2010-01-01

    One of the first things we think about when someone mentions physics is the machines. But behind the machines, there are the men and women who design, build and operate them. In an exhibition at the Thinktank planetarium’s art gallery in Birmingham (UK), Claudia Marcelloni and her husband Neal Hartman—she is a photographer and Outreach Officer for ATLAS, while he is an engineer working on the ATLAS pixel detector—explore the human side of scientists.   The exhibition at the Thinktank Planetarium art gallery, Birmingham (UK). It all began two years ago with the publication of Exploring the mystery of matter, a book about ATLAS. “A Norwegian physicist friend, Heidi Sandaker, saw my photographs and suggested that I display them in a museum. I thought this was an interesting idea, except that the photos consisted entirely of depictions of machinery, with human beings completely absent. For me, showing the people who are behind the machines and the fascination ...

  19. Soft computing in machine learning

    CERN Document Server

    Park, Jooyoung; Inoue, Atsushi

    2014-01-01

    As users or consumers are now demanding smarter devices, intelligent systems are revolutionizing by utilizing machine learning. Machine learning as part of intelligent systems is already one of the most critical components in everyday tools ranging from search engines and credit card fraud detection to stock market analysis. You can train machines to perform some things, so that they can automatically detect, diagnose, and solve a variety of problems. The intelligent systems have made rapid progress in developing the state of the art in machine learning based on smart and deep perception. Using machine learning, the intelligent systems make widely applications in automated speech recognition, natural language processing, medical diagnosis, bioinformatics, and robot locomotion. This book aims at introducing how to treat a substantial amount of data, to teach machines and to improve decision making models. And this book specializes in the developments of advanced intelligent systems through machine learning. It...

  20. Machine Translation Effect on Communication

    DEFF Research Database (Denmark)

    Jensen, Mika Yasuoka; Bjørn, Pernille

    2011-01-01

    Intercultural collaboration facilitated by machine translation has gradually spread in various settings. Still, little is known as for the practice of machine-translation mediated communication. This paper investigates how machine translation affects intercultural communication in practice. Based...... determines communication process largely, our data indicates communication relies more on a dynamic process where participants establish common ground than on reproducibility and grammatical accuracy.......Intercultural collaboration facilitated by machine translation has gradually spread in various settings. Still, little is known as for the practice of machine-translation mediated communication. This paper investigates how machine translation affects intercultural communication in practice. Based...... on communication in which multilingual communication system is applied, we identify four communication types and its’ influences on stakeholders’ communication process, especially focusing on establishment and maintenance of common ground. Different from our expectation that quality of machine translation results...

  1. Effect of Ceramic Surface Treatments After Machine Grinding on the Biaxial Flexural Strength of Different CAD/CAM Dental Ceramics.

    Science.gov (United States)

    Bagheri, Hossein; Hooshmand, Tabassom; Aghajani, Farzaneh

    2015-09-01

    This study aimed to evaluate the effect of different ceramic surface treatments after machining grinding on the biaxial flexural strength (BFS) of machinable dental ceramics with different crystalline phases. Disk-shape specimens (10mm in diameter and 1.3mm in thickness) of machinable ceramic cores (two silica-based and one zirconia-based ceramics) were prepared. Each type of the ceramic surfaces was then randomly treated (n=15) with different treatments as follows: 1) machined finish as control, 2) machined finish and sandblasting with alumina, and 3) machined finish and hydrofluoric acid etching for the leucite and lithium disilicate-based ceramics, and for the zirconia; 1) machined finish and post-sintered as control, 2) machined finish, post-sintered, and sandblasting, and 3) machined finish, post-sintered, and Nd;YAG laser irradiation. The BFS were measured in a universal testing machine. Data based were analyzed by ANOVA and Tukey's multiple comparisons post-hoc test (α=0.05). The mean BFS of machined finish only surfaces for leucite ceramic was significantly higher than that of sandblasted (P=0.001) and acid etched surfaces (P=0.005). A significantly lower BFS was found after sandblasting for lithium disilicate compared with that of other groups (Pceramics was affected by the type of ceramic material and surface treatment method. Sandblasting with alumina was detrimental to the strength of only silica-based ceramics. Nd:YAG laser irradiation may lead to substantial strength degradation of zirconia.

  2. Laser-Treated Titanium Implants: An In Vivo Histomorphometric and Biomechanical Analysis.

    Science.gov (United States)

    Trisi, Paolo; Berardini, Marco; Colagiovanni, Marco; Berardi, Davide; Perfetti, Giorgio

    2016-10-01

    The aim of the present histological and biomechanical analysis was to compare, in vivo, the strength and quality of osseointegration between a laser-treated implant surface and a standard machined surface. Customized titanium implants, having 2 different surfaces, were used. Implants were longitudinally split in the 2 surfaces: one side was laser treated and the opposite one had a machined surface. Eight implants were inserted in the iliac crest of 2 sheep: 4 with a split laser and machined surfaces, 2 with a completely laser-treated surface, and 2 with fully machined surfaces. The animals were killed 8 weeks after the placement of implants. The histomorphometric and biomechanical parameters calculated for each surface were the bone-implant contact (%BIC) and the reverse torque value (RTV) RESULTS:: The RTV of the laser-treated implants were about 3-fold higher than that of the machined implants. The histomorphometric results showed a significant difference of %BIC around 30% between the laser surfaces compared to the machined ones. The present study showed that laser surface treatment induces better osteointegration than machined surface. The laser-treated surface seems to be able to increase the osseointegration amount in respect to the machined implants.

  3. Charge-transfer reaction of 2,3-dichloro-1,4-naphthoquinone with crizotinib: Spectrophotometric study, computational molecular modeling and use in development of microwell assay for crizotinib.

    Science.gov (United States)

    Alzoman, Nourah Z; Alshehri, Jamilah M; Darwish, Ibrahim A; Khalil, Nasr Y; Abdel-Rahman, Hamdy M

    2015-01-01

    The reaction of 2,3-dichloro-1,4-naphthoquinone (DCNQ) with crizotinib (CZT; a novel drug used for treatment of non-small cell lung cancer) was investigated in different solvents of varying dielectric constants and polarity indexes. The reaction produced a red-colored product. Spectrophotometric investigations confirmed that the reaction proceeded through charge-transfer (CT) complex formation. The molar absorptivity of the complex was found to be linearly correlated with the dielectric constant and polarity index of the solvent; the correlation coefficients were 0.9567 and 0.9069, respectively. The stoichiometric ratio of DCNQ:CZT was found to be 2:1 and the association constant of the complex was found to be 1.07 × 10(2) l/mol. The kinetics of the reaction was studied; the order of the reaction, rate and rate constant were determined. Computational molecular modeling for the complex between DCNQ and CZT was conducted, the sites of interaction on CZT molecule were determined, and the mechanism of the reaction was postulated. The reaction was employed as a basis in the development of a novel 96-microwell assay for CZT in a linear range of 4-500 μg/ml. The assay limits of detection and quantitation were 2.06 and 6.23 μg/ml, respectively. The assay was validated as per the guidelines of the International Conference on Harmonization (ICH) and successfully applied to the analysis of CZT in its bulk and capsules with good accuracy and precision. The assay has high throughput and consumes a minimum volume of organic solvents thus it reduces the exposures of the analysts to the toxic effects of organic solvents, and significantly reduces the analysis cost.

  4. Case study of virtual reality in CNC machine tool exhibition

    Directory of Open Access Journals (Sweden)

    Kao Yung-Chou

    2017-01-01

    laser-assisted milling machine motion simulation has also been successfully conducted to show the expandability of the VR based technology. One can conclude that VR will be adopted and paid more and more attention in the future in helping CNC machine tool promotion. Further study could be extended to education and training system, and also for the maintenance system, too.

  5. Effects of laser bending on the microstructural constituents

    CSIR Research Space (South Africa)

    Tshabalala, L

    2012-01-01

    Full Text Available . Hofer3 & L. Schafer3 1Tshwane University of Technology 2National Laser Centre CSIR Pretoria 3Fraunhofer IST, Germany ABSTRACT Laser machining which is a non-contact process that offers the advantage of machining advanced ceramics... International Congress on Applications of Lasers and Electro-Optics (ICALEO), Anaheim Marriott Hotel® Resort, USA, 23-27 September 2012 Process Control & Monitoring for Laser Micromaching of Si3N4 Ceramics L. Tshabalala1, S. Pityana2, J. Styne2, M...

  6. Welding Behavior of Free Machining Stainless Steel

    Energy Technology Data Exchange (ETDEWEB)

    BROOKS,JOHN A.; ROBINO,CHARLES V.; HEADLEY,THOMAS J.; MICHAEL,JOSEPH R.

    2000-07-24

    The weld solidification and cracking behavior of sulfur bearing free machining austenitic stainless steel was investigated for both gas-tungsten arc (GTA) and pulsed laser beam weld processes. The GTA weld solidification was consistent with those predicted with existing solidification diagrams and the cracking response was controlled primarily by solidification mode. The solidification behavior of the pulsed laser welds was complex, and often contained regions of primary ferrite and primary austenite solidification, although in all cases the welds were found to be completely austenite at room temperature. Electron backscattered diffraction (EBSD) pattern analysis indicated that the nature of the base metal at the time of solidification plays a primary role in initial solidification. The solid state transformation of austenite to ferrite at the fusion zone boundary, and ferrite to austenite on cooling may both be massive in nature. A range of alloy compositions that exhibited good resistance to solidification cracking and was compatible with both welding processes was identified. The compositional range is bounded by laser weldability at lower Cr{sub eq}/Ni{sub eq} ratios and by the GTA weldability at higher ratios. It was found with both processes that the limiting ratios were somewhat dependent upon sulfur content.

  7. Mineral mining machines

    Energy Technology Data Exchange (ETDEWEB)

    Mc Gaw, B.H.

    1984-01-01

    A machine for mining minerals is patented. It is a cutter loader with a drum actuating element of the worm type equipped with a multitude of cutting teeth reinforced with tungsten carbide. A feature of the patented machine is that all of the cutting teeth and holders on the drum have the identical design. This is achieved through selecting a slant angle for the cutting teeth which is the mean between the slant angle of the conventional radial teeth and the slant angle of the advance teeth. This, in turn, is provided thanks to the corresponding slant of the holders relative to the drum and (or) the slant of the cutting part of the teeth relative to their stems. Thus, the advance teeth projecting beyond the surface of the drum on the face side and providing upper and lateral clearances have the same angle of attack as the radial teeth, that is, from 20 to 35 degrees. A series of modifications of the cutting teeth is patented. One of the designs allows the cutting tooth to occupy a varying position relative to the drum, from the conventional vertical to an inverted, axially projecting position. In the last case the tooth in the extraction process provides the upper and lateral clearances for the drum on the face side. Among the different modifications of the cutting teeth, a design is proposed which provides for the presence of a stem which is shaped like a truncated cone. This particular stem is designed for use jointly with a wedge which unfastens the teeth and is placed in a holder. The latter is completed in a transverse slot thanks to which the rear end of the stem is compressed, which simplifies replacement of a tooth. Channels are provided in the patented machine for feeding water to the worm spiral, the holders and the cutting teeth themselves in order to deal with dust.

  8. Advanced Machine learning Algorithm Application for Rotating Machine Health Monitoring

    Energy Technology Data Exchange (ETDEWEB)

    Kanemoto, Shigeru; Watanabe, Masaya [The University of Aizu, Aizuwakamatsu (Japan); Yusa, Noritaka [Tohoku University, Sendai (Japan)

    2014-08-15

    The present paper tries to evaluate the applicability of conventional sound analysis techniques and modern machine learning algorithms to rotating machine health monitoring. These techniques include support vector machine, deep leaning neural network, etc. The inner ring defect and misalignment anomaly sound data measured by a rotating machine mockup test facility are used to verify the above various kinds of algorithms. Although we cannot find remarkable difference of anomaly discrimination performance, some methods give us the very interesting eigen patterns corresponding to normal and abnormal states. These results will be useful for future more sensitive and robust anomaly monitoring technology.

  9. Laser generating metallic components

    Science.gov (United States)

    McLean, Marc A.; Shannon, G. J.; Steen, William M.

    1997-04-01

    Recent developments in rapid prototyping have led to the concept of laser generating, the first additive manufacturing technology. This paper presents an innovative process of depositing multi-layer tracks, by fusing successive powder tracks, to generate three dimensional components, thereby offering an alternative to casting for small metal component manufacture. A coaxial nozzle assembly has been designed and manufactured enabling consistent omni-directional multi-layer deposition. In conjunction with this the software route from a CAD drawing to machine code generation has been established. The part is manufactured on a six axes machining center incorporating a 1.8 kW carbon-dioxide laser, providing an integrated opto-mechanical workstation. The part build-up program is controlled by a P150 host computer, linked directly to the DNC machining center. The direct manufacturing route is shown, including initial examples of simple objects (primitives -- cube, cylinder, cone) leading to more complex turbine blade generation, incorporating build-up techniques and the associated mechanical properties.

  10. Diamond Measuring Machine

    Energy Technology Data Exchange (ETDEWEB)

    Krstulic, J.F.

    2000-01-27

    The fundamental goal of this project was to develop additional capabilities to the diamond measuring prototype, work out technical difficulties associated with the original device, and perform automated measurements which are accurate and repeatable. For this project, FM and T was responsible for the overall system design, edge extraction, and defect extraction and identification. AccuGem provided a lab and computer equipment in Lawrence, 3D modeling, industry expertise, and sets of diamonds for testing. The system executive software which controls stone positioning, lighting, focusing, report generation, and data acquisition was written in Microsoft Visual Basic 6, while data analysis and modeling were compiled in C/C++ DLLs. All scanning parameters and extracted data are stored in a central database and available for automated analysis and reporting. The Phase 1 study showed that data can be extracted and measured from diamond scans, but most of the information had to be manually extracted. In this Phase 2 project, all data required for geometric modeling and defect identification were automatically extracted and passed to a 3D modeling module for analysis. Algorithms were developed which automatically adjusted both light levels and stone focus positioning for each diamond-under-test. After a diamond is analyzed and measurements are completed, a report is printed for the customer which shows carat weight, summarizes stone geometry information, lists defects and their size, displays a picture of the diamond, and shows a plot of defects on a top view drawing of the stone. Initial emphasis of defect extraction was on identification of feathers, pinpoints, and crystals. Defects were plotted color-coded by industry standards for inclusions (red), blemishes (green), and unknown defects (blue). Diamonds with a wide variety of cut quality, size, and number of defects were tested in the machine. Edge extraction, defect extraction, and modeling code were tested for

  11. Tribology in machine design

    CERN Document Server

    Stolarski, T A

    1990-01-01

    Tribology in Machine Design aims to promote a better appreciation of the increasingly important role played by tribology at the design stage in engineering. This book shows how algorithms developed from the basic principles of tribology can be used in a range of practical applications. The concept of tribodesign is introduced in Chapter 1. Chapter 2 is devoted to a brief discussion of the basic principles of tribology, including some concepts and models of lubricated wear and friction under complex kinematic conditions. Elements of contact mechanics, presented in Chapter 3, are confined to the

  12. Quantum adiabatic machine learning

    CERN Document Server

    Pudenz, Kristen L

    2011-01-01

    We develop an approach to machine learning and anomaly detection via quantum adiabatic evolution. In the training phase we identify an optimal set of weak classifiers, to form a single strong classifier. In the testing phase we adiabatically evolve one or more strong classifiers on a superposition of inputs in order to find certain anomalous elements in the classification space. Both the training and testing phases are executed via quantum adiabatic evolution. We apply and illustrate this approach in detail to the problem of software verification and validation.

  13. Daphne machine project

    Energy Technology Data Exchange (ETDEWEB)

    Vignola, G. and Daphne Project Team [Istituto Nazionale di Fisica Nucleare, Frascati (Italy)

    1996-07-01

    Daphne, a high luminosity e{sup +}/e{sup -} {Phi} factory, is presently under construction in Frascati. The beginning of the collider commissioning is scheduled by winter 1997, with a short term luminosity goal L=1.3 10{sup 32} cm{sup -2} sec{sup -1}. Daphne shall be the first of the new generation of very high luminosity colliders, called factories, to come in operation. Other factories under construction are PEP-II and KEK-B: first collision, for both machines, is planned for 1998.

  14. CENTRIFUGAL CASTING MACHINE

    Science.gov (United States)

    Shuck, A.B.

    1958-04-01

    A device is described that is specifically designed to cast uraniumn fuel rods in a vacuunn, in order to obtain flawless, nonoxidized castings which subsequently require a maximum of machining or wastage of the expensive processed material. A chamber surrounded with heating elements is connected to the molds, and the entire apparatus is housed in an airtight container. A charge of uranium is placed in the chamber, heated, then is allowed to flow into the molds While being rotated. Water circulating through passages in the molds chills the casting to form a fine grained fuel rod in nearly finished form.

  15. Electrical machines with Matlab

    CERN Document Server

    Gonen, Turan

    2011-01-01

    Basic ConceptsDistribution SystemImpact of Dispersed Storage and GenerationBrief Overview of Basic Electrical MachinesReal and Reactive Powers in Single-Phase AC CircuitsThree-Phase CircuitsThree-Phase SystemsUnbalanced Three-Phase LoadsMeasurement of Average Power in Three-Phase CircuitsPower Factor CorrectionMagnetic CircuitsMagnetic Field of Current-Carrying ConductorsAmpère's Magnetic Circuital LawMagnetic CircuitsMagnetic Circuit with Air GapBrief Review of FerromagnetismMagnetic Core LossesHow to Determine Flux for a Given MMFPermanent MagnetsTransformersTransformer ConstructionBrief Rev

  16. Lasers technology

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2011-07-01

    The Lasers Technology Program of IPEN is committed to the development of new lasers based on the research of optical materials and new technologies, as well to laser applications in several areas: Nuclear, Medicine, Dentistry, Industry, Environment and Advanced Research. The Program is basically divided into two main areas: Material and Laser Development and Laser Applications.

  17. Optimization of TM-Doped Phosphosilicate Glass for High Power Fiber Lasers

    Science.gov (United States)

    2016-04-28

    High power fiber lasers have been revolutionizing machining in manufacturing in the past decade. Increasingly, automotive industries are turning to the...micro- machining at precision much beyond current mechanical tools with a focused laser beam and high throughput machining of much harder materials...such as glass and ceramics, again way beyond the capability of current mechanical tools. Some of the key applications include drilling micron-size

  18. Machining of Complex Sculptured Surfaces

    CERN Document Server

    2012-01-01

    The machining of complex sculptured surfaces is a global technological topic in modern manufacturing with relevance in both industrialized and emerging in countries particularly within the moulds and dies sector whose applications include highly technological industries such as the automotive and aircraft industry. Machining of Complex Sculptured Surfaces considers new approaches to the manufacture of moulds and dies within these industries. The traditional technology employed in the manufacture of moulds and dies combined conventional milling and electro-discharge machining (EDM) but this has been replaced with  high-speed milling (HSM) which has been applied in roughing, semi-finishing and finishing of moulds and dies with great success. Machining of Complex Sculptured Surfaces provides recent information on machining of complex sculptured surfaces including modern CAM systems and process planning for three and five axis machining as well as explanations of the advantages of HSM over traditional methods ra...

  19. Learning thermodynamics with Boltzmann machines

    Science.gov (United States)

    Torlai, Giacomo; Melko, Roger G.

    2016-10-01

    A Boltzmann machine is a stochastic neural network that has been extensively used in the layers of deep architectures for modern machine learning applications. In this paper, we develop a Boltzmann machine that is capable of modeling thermodynamic observables for physical systems in thermal equilibrium. Through unsupervised learning, we train the Boltzmann machine on data sets constructed with spin configurations importance sampled from the partition function of an Ising Hamiltonian at different temperatures using Monte Carlo (MC) methods. The trained Boltzmann machine is then used to generate spin states, for which we compare thermodynamic observables to those computed by direct MC sampling. We demonstrate that the Boltzmann machine can faithfully reproduce the observables of the physical system. Further, we observe that the number of neurons required to obtain accurate results increases as the system is brought close to criticality.

  20. 基于支持向量机回归的水体重金属激光诱导击穿光谱定量分析研究%Quantitative Analysis of Laser-Induced Breakdown Spectroscopy of Heavy Metals in Water Based on Support-Vector-Machine Regression

    Institute of Scientific and Technical Information of China (English)

    王春龙; 刘建国; 赵南京; 马明俊; 王寅; 胡丽; 张大海; 余洋; 孟德硕

    2013-01-01

    建立了基于自适应核的激光诱导击穿光谱支持向量机回归定量分析模型.通过石墨富集、洛伦兹拟合和碳内标归一化,增强等离子体信号强度,减小环境噪声和能量抖动对水体重金属浓度测量的影响.实现了基于支持向量机回归智能算法的激光诱导击穿光谱定量分析.铅铜的平均相对标准偏差分别为6.4361%和6.9291%,最大相对标准偏差分别为9.1009%和8.9280%,平均相对误差分别为1.6765%和1.2478%,最大相对误差分别为5.5759%和4.2604%,相关系数分别为0.9979和0.9997.该研究为进一步实现水中痕量金属元素的快速定量分析提供了方法和数据参考.%The quantitative analysis model of laser-induced breakdown spectroscopy with adaptive kernel is established. Effect of ambient noise and energy jitter in measured density of heavy metals is gradually removed by Lorentz fitting and carbon normalization, and the intensity of plasmas is enhanced by graphite enrichment. Quantitative analysis of laser-induced breakdown spectroscopy based on regression intelligent algorithm of support vector machine is achieved. The average relative standard deviations of lead and copper are 6.4361 % and 6.9291 % , and the maximum standard deviations are 9.1009% and 8. 9280% . The average relative errors of lead and copper are 1.6765% and 1.2478 %, and the maximum relative errors are 5. 5759% and4.2604%. The correlation coefficients of lead and copper are 0. 9979 and 0. 9997. Methods and reference data are provided for the further study of fast measurement of trace heavy metals in water by laser-induced breakdown spectroscopy.

  1. Machine learning with R cookbook

    CERN Document Server

    Chiu, Yu-Wei

    2015-01-01

    If you want to learn how to use R for machine learning and gain insights from your data, then this book is ideal for you. Regardless of your level of experience, this book covers the basics of applying R to machine learning through to advanced techniques. While it is helpful if you are familiar with basic programming or machine learning concepts, you do not require prior experience to benefit from this book.

  2. Machine learning in healthcare informatics

    CERN Document Server

    Acharya, U; Dua, Prerna

    2014-01-01

    The book is a unique effort to represent a variety of techniques designed to represent, enhance, and empower multi-disciplinary and multi-institutional machine learning research in healthcare informatics. The book provides a unique compendium of current and emerging machine learning paradigms for healthcare informatics and reflects the diversity, complexity and the depth and breath of this multi-disciplinary area. The integrated, panoramic view of data and machine learning techniques can provide an opportunity for novel clinical insights and discoveries.

  3. Autocoding State Machine in Erlang

    DEFF Research Database (Denmark)

    Guo, Yu; Hoffman, Torben; Gunder, Nicholas

    2008-01-01

    This paper presents an autocoding tool suit, which supports development of state machine in a model-driven fashion, where models are central to all phases of the development process. The tool suit, which is built on the Eclipse platform, provides facilities for the graphical specification...... of a state machine model. Once the state machine is specified, it is used as input to a code generation engine that generates source code in Erlang....

  4. Blinding Techniques in Randomized Controlled Trials of Laser Therapy: An Overview and Possible Solution

    Directory of Open Access Journals (Sweden)

    Ian Relf

    2008-01-01

    Full Text Available Low-level laser therapy has evidence accumulating about its effectiveness in a variety of medical conditions. We reviewed 51 double blind randomized controlled trials (RCTs of laser treatment. Analysis revealed 58% of trials showed benefit of laser over placebo. However, less than 5% of the trials had addressed beam disguise or allocation concealment in the laser machines used. Many of the trials used blinding methods that rely on staff cooperation and are therefore open to interference or bias. This indicates significant deficiencies in laser trial methodology. We report the development and preliminary testing of a novel laser machine that can blind both patient and operator to treatment allocation without staff participation. The new laser machine combines sealed preset and non-bypassable randomization codes, decoy lights and sound, and a conical perspex tip to overcome laser diode glow detection.

  5. Stacked Extreme Learning Machines.

    Science.gov (United States)

    Zhou, Hongming; Huang, Guang-Bin; Lin, Zhiping; Wang, Han; Soh, Yeng Chai

    2015-09-01

    Extreme learning machine (ELM) has recently attracted many researchers' interest due to its very fast learning speed, good generalization ability, and ease of implementation. It provides a unified solution that can be used directly to solve regression, binary, and multiclass classification problems. In this paper, we propose a stacked ELMs (S-ELMs) that is specially designed for solving large and complex data problems. The S-ELMs divides a single large ELM network into multiple stacked small ELMs which are serially connected. The S-ELMs can approximate a very large ELM network with small memory requirement. To further improve the testing accuracy on big data problems, the ELM autoencoder can be implemented during each iteration of the S-ELMs algorithm. The simulation results show that the S-ELMs even with random hidden nodes can achieve similar testing accuracy to support vector machine (SVM) while having low memory requirements. With the help of ELM autoencoder, the S-ELMs can achieve much better testing accuracy than SVM and slightly better accuracy than deep belief network (DBN) with much faster training speed.

  6. Interaction with Machine Improvisation

    Science.gov (United States)

    Assayag, Gerard; Bloch, George; Cont, Arshia; Dubnov, Shlomo

    We describe two multi-agent architectures for an improvisation oriented musician-machine interaction systems that learn in real time from human performers. The improvisation kernel is based on sequence modeling and statistical learning. We present two frameworks of interaction with this kernel. In the first, the stylistic interaction is guided by a human operator in front of an interactive computer environment. In the second framework, the stylistic interaction is delegated to machine intelligence and therefore, knowledge propagation and decision are taken care of by the computer alone. The first framework involves a hybrid architecture using two popular composition/performance environments, Max and OpenMusic, that are put to work and communicate together, each one handling the process at a different time/memory scale. The second framework shares the same representational schemes with the first but uses an Active Learning architecture based on collaborative, competitive and memory-based learning to handle stylistic interactions. Both systems are capable of processing real-time audio/video as well as MIDI. After discussing the general cognitive background of improvisation practices, the statistical modelling tools and the concurrent agent architecture are presented. Then, an Active Learning scheme is described and considered in terms of using different improvisation regimes for improvisation planning. Finally, we provide more details about the different system implementations and describe several performances with the system.

  7. Vector control of induction machines

    CERN Document Server

    Robyns, Benoit

    2012-01-01

    After a brief introduction to the main law of physics and fundamental concepts inherent in electromechanical conversion, ""Vector Control of Induction Machines"" introduces the standard mathematical models for induction machines - whichever rotor technology is used - as well as several squirrel-cage induction machine vector-control strategies. The use of causal ordering graphs allows systematization of the design stage, as well as standardization of the structure of control devices. ""Vector Control of Induction Machines"" suggests a unique approach aimed at reducing parameter sensitivity for

  8. Beam Transfer and Machine Protection

    CERN Document Server

    Kain, V

    2016-01-01

    Beam transfer, such as injection into or extraction from an accelerator, is one of the most critical moments in terms of machine protection in a high-intensity machine. Special equipment is used and machine protection aspects have to be taken into account in the design of the beam transfer concepts. A brief introduction of the principles of beam transfer and the equipment involved will be given in this lecture. The main concepts of machine protection for injection and extraction will be presented, with examples from the CERN SPS and LHC.

  9. Turing Automata and Graph Machines

    Directory of Open Access Journals (Sweden)

    Miklós Bartha

    2010-06-01

    Full Text Available Indexed monoidal algebras are introduced as an equivalent structure for self-dual compact closed categories, and a coherence theorem is proved for the category of such algebras. Turing automata and Turing graph machines are defined by generalizing the classical Turing machine concept, so that the collection of such machines becomes an indexed monoidal algebra. On the analogy of the von Neumann data-flow computer architecture, Turing graph machines are proposed as potentially reversible low-level universal computational devices, and a truly reversible molecular size hardware model is presented as an example.

  10. Achieving Small Structures in Thin NiTi Sheets for Medical Applications with Water Jet and Micro Machining: A Comparison

    Science.gov (United States)

    Frotscher, M.; Kahleyss, F.; Simon, T.; Biermann, D.; Eggeler, G.

    2011-07-01

    NiTi shape memory alloys (SMA) are used for a variety of applications including medical implants and tools as well as actuators, making use of their unique properties. However, due to the hardness and strength, in combination with the high elasticity of the material, the machining of components can be challenging. The most common machining techniques used today are laser cutting and electrical discharge machining (EDM). In this study, we report on the machining of small structures into binary NiTi sheets, applying alternative processing methods being well-established for other metallic materials. Our results indicate that water jet machining and micro milling can be used to machine delicate structures, even in very thin NiTi sheets. Further work is required to optimize the cut quality and the machining speed in order to increase the cost-effectiveness and to make both methods more competitive.

  11. Rapid mapping of volumetric machine errors using distance measurements

    Energy Technology Data Exchange (ETDEWEB)

    Krulewich, D.A.

    1998-04-01

    This paper describes a relatively inexpensive, fast, and easy to execute approach to maping the volumetric errors of a machine tool, coordinate measuring machine, or robot. An error map is used to characterize a machine or to improve its accuracy by compensating for the systematic errors. The method consists of three steps: (1) models the relationship between volumetric error and the current state of the machine, (2) acquiring error data based on distance measurements throughout the work volume; and (3)fitting the error model using the nonlinear equation for the distance. The error model is formulated from the kinematic relationship among the six degrees of freedom of error an each moving axis. Expressing each parametric error as function of position each is combined to predict the error between the functional point and workpiece, also as a function of position. A series of distances between several fixed base locations and various functional points in the work volume is measured using a Laser Ball Bar (LBB). Each measured distance is a non-linear function dependent on the commanded location of the machine, the machine error, and the location of the base locations. Using the error model, the non-linear equation is solved producing a fit for the error model Also note that, given approximate distances between each pair of base locations, the exact base locations in the machine coordinate system determined during the non-linear filling procedure. Furthermore, with the use of 2048 more than three base locations, bias error in the measuring instrument can be removed The volumetric errors of three-axis commercial machining center have been mapped using this procedure. In this study, only errors associated with the nominal position of the machine were considered Other errors such as thermally induced and load induced errors were not considered although the mathematical model has the ability to account for these errors. Due to the proprietary nature of the projects we are

  12. Production Machine Shop Employment Competencies. Part Four: The Milling Machine.

    Science.gov (United States)

    Bishart, Gus; Werner, Claire

    Competencies for production machine shop are provided for the fourth of four topic areas: the milling machine. Each competency appears in a one-page format. It is presented as a goal statement followed by one or more "indicator" statements, which are performance objectives describing an ability that, upon attainment, will establish…

  13. Standardized Curriculum for Machine Tool Operation/Machine Shop.

    Science.gov (United States)

    Mississippi State Dept. of Education, Jackson. Office of Vocational, Technical and Adult Education.

    Standardized vocational education course titles and core contents for two courses in Mississippi are provided: machine tool operation/machine shop I and II. The first course contains the following units: (1) orientation; (2) shop safety; (3) shop math; (4) measuring tools and instruments; (5) hand and bench tools; (6) blueprint reading; (7)…

  14. Machine performance assessment and enhancement for a hexapod machine

    Energy Technology Data Exchange (ETDEWEB)

    Mou, J.I. [Arizona State Univ., Tempe, AZ (United States); King, C. [Sandia National Labs., Livermore, CA (United States). Integrated Manufacturing Systems Center

    1998-03-19

    The focus of this study is to develop a sensor fused process modeling and control methodology to model, assess, and then enhance the performance of a hexapod machine for precision product realization. Deterministic modeling technique was used to derive models for machine performance assessment and enhancement. Sensor fusion methodology was adopted to identify the parameters of the derived models. Empirical models and computational algorithms were also derived and implemented to model, assess, and then enhance the machine performance. The developed sensor fusion algorithms can be implemented on a PC-based open architecture controller to receive information from various sensors, assess the status of the process, determine the proper action, and deliver the command to actuators for task execution. This will enhance a hexapod machine`s capability to produce workpieces within the imposed dimensional tolerances.

  15. Theory and practice in machining systems

    CERN Document Server

    Ito, Yoshimi

    2017-01-01

    This book describes machining technology from a wider perspective by considering it within the machining space. Machining technology is one of the metal removal activities that occur at the machining point within the machining space. The machining space consists of structural configuration entities, e.g., the main spindle, the turret head and attachments such the chuck and mandrel, and also the form-generating movement of the machine tool itself. The book describes fundamental topics, including the form-generating movement of the machine tool and the important roles of the attachments, before moving on to consider the supply of raw materials into the machining space, and the discharge of swarf from it, and then machining technology itself. Building on the latest research findings “Theory and Practice in Machining System” discusses current challenges in machining. Thus, with the inclusion of introductory and advanced topics, the book can be used as a guide and survey of machining technology for students an...

  16. Effect of Ceramic Surface Treatments After Machine Grinding on the Biaxial Flexural Strength of Different CAD/CAM Dental Ceramics

    Science.gov (United States)

    Bagheri, Hossein; Aghajani, Farzaneh

    2015-01-01

    Objectives: This study aimed to evaluate the effect of different ceramic surface treatments after machining grinding on the biaxial flexural strength (BFS) of machinable dental ceramics with different crystalline phases. Materials and Methods: Disk-shape specimens (10mm in diameter and 1.3mm in thickness) of machinable ceramic cores (two silica-based and one zirconia-based ceramics) were prepared. Each type of the ceramic surfaces was then randomly treated (n=15) with different treatments as follows: 1) machined finish as control, 2) machined finish and sandblasting with alumina, and 3) machined finish and hydrofluoric acid etching for the leucite and lithium disilicate-based ceramics, and for the zirconia; 1) machined finish and post-sintered as control, 2) machined finish, post-sintered, and sandblasting, and 3) machined finish, post-sintered, and Nd;YAG laser irradiation. The BFS were measured in a universal testing machine. Data based were analyzed by ANOVA and Tukey’s multiple comparisons post-hoc test (α=0.05). Results: The mean BFS of machined finish only surfaces for leucite ceramic was significantly higher than that of sandblasted (P=0.001) and acid etched surfaces (P=0.005). A significantly lower BFS was found after sandblasting for lithium disilicate compared with that of other groups (P<0.05). Sandblasting significantly increased the BFS for the zirconia (P<0.05), but the BFS was significantly decreased after laser irradiation (P<0.05). Conclusions: The BFS of the machinable ceramics was affected by the type of ceramic material and surface treatment method. Sandblasting with alumina was detrimental to the strength of only silica-based ceramics. Nd:YAG laser irradiation may lead to substantial strength degradation of zirconia. PMID:27148372

  17. Semantic Vector Machines

    CERN Document Server

    Vincent, Etter

    2011-01-01

    We first present our work in machine translation, during which we used aligned sentences to train a neural network to embed n-grams of different languages into an $d$-dimensional space, such that n-grams that are the translation of each other are close with respect to some metric. Good n-grams to n-grams translation results were achieved, but full sentences translation is still problematic. We realized that learning semantics of sentences and documents was the key for solving a lot of natural language processing problems, and thus moved to the second part of our work: sentence compression. We introduce a flexible neural network architecture for learning embeddings of words and sentences that extract their semantics, propose an efficient implementation in the Torch framework and present embedding results comparable to the ones obtained with classical neural language models, while being more powerful.

  18. Regularized maximum correntropy machine

    KAUST Repository

    Wang, Jim Jing-Yan

    2015-02-12

    In this paper we investigate the usage of regularized correntropy framework for learning of classifiers from noisy labels. The class label predictors learned by minimizing transitional loss functions are sensitive to the noisy and outlying labels of training samples, because the transitional loss functions are equally applied to all the samples. To solve this problem, we propose to learn the class label predictors by maximizing the correntropy between the predicted labels and the true labels of the training samples, under the regularized Maximum Correntropy Criteria (MCC) framework. Moreover, we regularize the predictor parameter to control the complexity of the predictor. The learning problem is formulated by an objective function considering the parameter regularization and MCC simultaneously. By optimizing the objective function alternately, we develop a novel predictor learning algorithm. The experiments on two challenging pattern classification tasks show that it significantly outperforms the machines with transitional loss functions.

  19. Machine Learning Exciton Dynamics

    CERN Document Server

    Häse, Florian; Pyzer-Knapp, Edward; Aspuru-Guzik, Alán

    2015-01-01

    Obtaining the exciton dynamics of large photosynthetic complexes by using mixed quantum mechanics/molecular mechanics (QM/MM) is computationally demanding. We propose a machine learning technique, multi-layer perceptrons, as a tool to reduce the time required to compute excited state energies. With this approach we predict time-dependent density functional theory (TDDFT) excited state energies of bacteriochlorophylls in the Fenna-Matthews-Olson (FMO) complex. Additionally we compute spectral densities and exciton populations from the predictions. Different methods to determine multi-layer perceptron training sets are introduced, leading to several initial data selections. In addition, we compute spectral densities and exciton populations. Once multi-layer perceptrons are trained, predicting excited state energies was found to be significantly faster than the corresponding QM/MM calculations. We showed that multi-layer perceptrons can successfully reproduce the energies of QM/MM calculations to a high degree o...

  20. Training Restricted Boltzmann Machines

    DEFF Research Database (Denmark)

    Fischer, Asja

    Restricted Boltzmann machines (RBMs) are probabilistic graphical models that can also be interpreted as stochastic neural networks. Training RBMs is known to be challenging. Computing the likelihood of the model parameters or its gradient is in general computationally intensive. Thus, training...... relies on sampling based approximations of the log-likelihood gradient. I will present an empirical and theoretical analysis of the bias of these approximations and show that the approximation error can lead to a distortion of the learning process. The bias decreases with increasing mixing rate...... of the applied sampling procedure and I will introduce a transition operator that leads to faster mixing. Finally, a different parametrisation of RBMs will be discussed that leads to better learning results and more robustness against changes in the data representation....