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Sample records for thermal lens technique

  1. Simple technique to evaluate the thermal lens strength of a laser material. SAIP 2005 Talk C-20

    CSIR Research Space (South Africa)

    Esser, D

    2005-01-01

    Full Text Available The presentation is about the simple technique to measure the thermal lens; Same pumping conditions as real laser; Same cooling configuration as real laser; Comparative experiment made; Nd:YVO4 has smaller thermal lens than Nd:GdVO4; Nd:GdVO4 has...

  2. High-Quality Large-Magnification Polymer Lens from Needle Moving Technique and Thermal Assisted Moldless Fabrication Process.

    Directory of Open Access Journals (Sweden)

    Ratthasart Amarit

    Full Text Available The need of mobile microscope is escalating as well as the demand of high quality optical components in low price. We report here a novel needle moving technique to fabricate milli-size lens together with thermal assist moldless method. Our proposed protocol is able to create a high tensile strength structure of the lens and its base which is beneficial for exploiting in convertinga smart phone to be a digital microscope. We observe that no bubble trapped in a lens when this technique is performed which can overcome a challenge problem found in a typical dropping technique. We demonstrate the symmetry, smoothness and micron-scale resolution of the fabricated structure. This proposed technique is promising to serve as high quality control mass production without any expensive equipment required.

  3. Cavity Ring Down and Thermal Lens Techniques Applied to Vibrational Spectroscopy of Gases and Liquids

    Science.gov (United States)

    Nyaupane, Parashu Ram

    Infrared (IR) and near-infrared (NIR) region gas temperature sensors have been used in the past because of its non-intrusive character and fast time response. In this dissertation cavity ring down (CRD) absorption of oxygen around the region 760 nm has been used to measure the temperature of flowing air in an open optical cavity. This sensor could be a convenient method for measuring the temperature at the input (cold air) and output (hot air) after cooling the blades of a gas turbine. The results could contribute to improvements in turbine blade cooling designs. Additionally, it could be helpful for high temperature measurement in harsh conditions like flames, boilers, and industrial pyrolysis ovens as well as remote sensing. We are interested in experiments that simulate the liquid methane and ethane lakes on Titan which is around the temperature of 94 K. Our specific goal is to quantify the solubility of unsaturated hydrocarbons in liquid ethane and methane. However, it is rather complicated to do so because of the low temperatures, low solubility and solvent effects. So, it is wise to do the experiments at higher temperature and test the suitability of the techniques. In these projects, we were trying to explore if our existing laboratory techniques were sensitive enough to obtain the solubility of unsaturated hydrocarbons in liquid ethane. First, we studied the thermal lens spectroscopy (TLS) of the (Deltav = 6) C-H overtone of benzene and naphthalene in hexane and CCl4 at room temperature.

  4. Thermal Diffusivity Measurements in Edible Oils using Transient Thermal Lens

    Science.gov (United States)

    Valdez, R. Carbajal.; Pérez, J. L. Jiménez.; Cruz-Orea, A.; Martín-Martínez, E. San.

    2006-11-01

    Time resolved thermal lens (TL) spectrometry is applied to the study of the thermal diffusivity of edible oils such as olive, and refined and thermally treated avocado oils. A two laser mismatched-mode experimental configuration was used, with a He Ne laser as a probe beam and an Ar+ laser as the excitation one. The characteristic time constant of the transient thermal lens was obtained by fitting the experimental data to the theoretical expression for a transient thermal lens. The results showed that virgin olive oil has a higher thermal diffusivity than for refined and thermally treated avocado oils. This measured thermal property may contribute to a better understanding of the quality of edible oils, which is very important in the food industry. The thermal diffusivity results for virgin olive oil, obtained from this technique, agree with those reported in the literature.

  5. Enhanced thermal lens effect in gold nanoparticle-doped Lyotropic liquid crystal by nanoparticle clustering probed by Z-scan technique

    International Nuclear Information System (INIS)

    Gomez, S.L.; Lenart, V.M.

    2015-01-01

    This work presents an experimental study of the thermal lens effect in Au nanoparticles-doped lyotropic liquid crystals under cw 532 nm optical excitation. Spherical Au nanoparticles of about 12 nm were prepared by Turkevich’s method, and the lyotropic liquid crystal was a ternary mixture of SDS, 1-DeOH, and water that exhibits an isotropic phase at room temperature. The lyotropic matrix induces aggregation of the nanoparticles, leading to a broad and a red-shifted surface plasmon resonance. The thermal nonlinear optical refraction coefficient n 2 increases as a power of number density of nanoparticles, being possible to address this behavior to nanoparticle clustering. (author)

  6. Enhanced thermal lens effect in gold nanoparticle-doped Lyotropic liquid crystal by nanoparticle clustering probed by Z-scan technique

    Energy Technology Data Exchange (ETDEWEB)

    Gomez, S.L.; Lenart, V.M., E-mail: sgomez@uepg.br [Universidade Estadual de Ponta Grossa (UEPG), PR (Brazil). Dept. de Fisica; Turchiello, R.T. [Universidade Federal Tecnologica do Parana (UFTPR), Ponta Grossa, PR (Brazil). Dept. de Fisica; Goya, G.F. [Department of Condensed Matter Physics, Aragon Institute of Nanoscience, Zaragoza (Spain)

    2015-10-01

    This work presents an experimental study of the thermal lens effect in Au nanoparticles-doped lyotropic liquid crystals under cw 532 nm optical excitation. Spherical Au nanoparticles of about 12 nm were prepared by Turkevich’s method, and the lyotropic liquid crystal was a ternary mixture of SDS, 1-DeOH, and water that exhibits an isotropic phase at room temperature. The lyotropic matrix induces aggregation of the nanoparticles, leading to a broad and a red-shifted surface plasmon resonance. The thermal nonlinear optical refraction coefficient n{sub 2} increases as a power of number density of nanoparticles, being possible to address this behavior to nanoparticle clustering. (author)

  7. Thermal lens measurements in the cornea.

    Science.gov (United States)

    Venkatesh, S; Guthrie, S; Cruickshank, F R; Bailey, R T; Foulds, W S; Lee, W R

    1985-02-01

    Q-switched pulses from a neodymium/YAG (yttrium-aluminium-garnet) laser were passed through corneal discs taken from the enucleated eyes of three baboons and four rabbits. The time course of heat dissipation following absorption of laser energy by the tissue was studied with the use of a second continuous wave laser beam acting as a probe. It was found that the absorption of each neodymium/YAG pulse created a transient divergent lens within the cornea as theoretical considerations predicted. The relaxation time that characterised the decay of this thermal lens for a 1/e laser beam diameter of 2.0 mm was found to be 2.3 +/- 0.1 s (mean +/- standard error for 12 separate groups of measurements). Our results show that Q-switched laser pulses passing through apparently unaffected transparent tissues can induce thermal lens effects which persist for several seconds. The optical transfer of each pulse in a stream will be identical only if enough time is left between pulses for the tissues to return to their initial state. Therefore, when such laser pulses sharply focused to perform high precision intraocular surgery are used, thermal lensing in the transparent ocular media must limit the rate at which pulses can be usefully delivered.

  8. Applications of thermal lens spectrometry in food industry and agriculture.

    NARCIS (Netherlands)

    Franko, M.; Bicanic, D.; Gibkes, J.; Bremer, M.; Akkermans, E.

    1996-01-01

    Applications of CO laser dual beam thermal lens spectrometry (TLS) for detection and characterization of fatty acids, aldehydes, pesticides, and herbicides in liquid samples are described. Also reported is the first TLS measurement of thermal conductivity for oleic acid.

  9. Thermal diffusivity imaging with the thermal lens microscope.

    Science.gov (United States)

    Dada, Oluwatosin O; Feist, Peter E; Dovichi, Norman J

    2011-12-01

    A coaxial thermal lens microscope was used to generate images based on both the absorbance and thermal diffusivity of histological samples. A pump beam was modulated at frequencies ranging from 50 kHz to 5 MHz using an acousto-optic modulator. The pump and a CW probe beam were combined with a dichroic mirror, directed into an inverted microscope, and focused onto the specimen. The change in the transmitted probe beam's center intensity was detected with a photodiode. The photodiode's signal and a reference signal from the modulator were sent to a high-speed lock-in amplifier. The in-phase and quadrature signals were recorded as a sample was translated through the focused beams and used to generate images based on the amplitude and phase of the lock-in amplifier's signal. The amplitude is related to the absorbance and the phase is related to the thermal diffusivity of the sample. Thin sections of stained liver and bone tissues were imaged; the contrast and signal-to-noise ratio of the phase image was highest at frequencies from 0.1-1 MHz and dropped at higher frequencies. The spatial resolution was 2.5 μm for both amplitude and phase images, limited by the pump beam spot size. © 2011 Optical Society of America

  10. Two-laser thermal-lens determination of phosphorus in silicon

    International Nuclear Information System (INIS)

    Grishko, V.I.; Gol'dshtein, M.M.; Grishko, V.P.; Yudelevich, I.G.

    1986-01-01

    Laser thermal-lens spectrophotometry is a high-sensitivity method of measuring absorptivity, where the signal is the relative intensity change at the beam center after passage through the medium, which absorbs at the laser wavelength. The two-lens method is discussed here which employs a high-power laser to induce the lens, while the absorptivity is measured from the intensity change in the beam from a continous wave low-power test laser at a wavelength different from that for the inducing one. This paper uses two-laser thermal-lens techniques to determine phosphorus in silicon. Phosphorus is determined as the ionic association of molybdophosphoric acid with auramine

  11. Investigation into photostability of soybean oils by thermal lens spectroscopy

    Science.gov (United States)

    Savi, E. L.; Malacarne, L. C.; Baesso, M. L.; Pintro, P. T. M.; Croge, C.; Shen, J.; Astrath, N. G. C.

    2015-06-01

    Assessment of photochemical stability is essential for evaluating quality and the shelf life of vegetable oils, which are very important aspects of marketing and human health. Most of conventional methods used to investigate oxidative stability requires long time experimental procedures with high consumption of chemical inputs for the preparation or extraction of sample compounds. In this work we propose a time-resolved thermal lens method to analyze photostability of edible oils by quantitative measurement of photoreaction cross-section. An all-numerical routine is employed to solve a complex theoretical problem involving photochemical reaction, thermal lens effect, and mass diffusion during local laser excitation. The photostability of pure oil and oils with natural and synthetic antioxidants is investigated. The thermal lens results are compared with those obtained by conventional methods, and a complete set of physical properties of the samples is presented.

  12. A thermal lens response of the two components liquid in a thin Him cell

    International Nuclear Information System (INIS)

    Ivanov, V I; Ivanova, G D

    2016-01-01

    It was proposed a new thermal lens scheme with a thin layer of cell thickness which is significantly less than the size of the beam. As a result the exact analytical expression for the thermal lens response is achieved, taking into account the thermal lens in the windows of the cell. (paper)

  13. Thermo-optical properties of Nd{sup 3+} doped phosphate glass determined by thermal lens and lifetime measurements

    Energy Technology Data Exchange (ETDEWEB)

    Martins, V.M. [Instituto de Física, Universidade Federal de Uberlândia, CEP38408-902 Uberlandia, Minas Gerais (Brazil); CIMAP – Centre de recherche sur les Ions, les Matériaux et la Photonique UMR 6252 CEA-CNRS-ENSICAEN-Université de Caen, 14050 Caen Cedex 4 (France); Messias, D.N., E-mail: dnmessias@infis.ufu.br [Instituto de Física, Universidade Federal de Uberlândia, CEP38408-902 Uberlandia, Minas Gerais (Brazil); Doualan, J.L.; Braud, A.; Camy, P. [CIMAP – Centre de recherche sur les Ions, les Matériaux et la Photonique UMR 6252 CEA-CNRS-ENSICAEN-Université de Caen, 14050 Caen Cedex 4 (France); Dantas, N.O. [Instituto de Física, Universidade Federal de Uberlândia, CEP38408-902 Uberlandia, Minas Gerais (Brazil); CIMAP – Centre de recherche sur les Ions, les Matériaux et la Photonique UMR 6252 CEA-CNRS-ENSICAEN-Université de Caen, 14050 Caen Cedex 4 (France); Instituto de Física de São Carlos, Universidade de São Paulo, USP, CEP 13560-970 São Carlos, SP (Brazil); Catunda, T. [Instituto de Física de São Carlos, Universidade de São Paulo, USP, CEP 13560-970 São Carlos, SP (Brazil); Pilla, V.; Andrade, A.A. [Instituto de Física, Universidade Federal de Uberlândia, CEP38408-902 Uberlandia, Minas Gerais (Brazil); and others

    2015-06-15

    In this paper the Normalized Lifetime Thermal Lens technique was applied to a set of Nd-doped phosphate samples in order to obtain its thermal and optical properties. Moreover, radiative emission properties were obtained by the Judd–Ofelt theory. The luminescence quantum efficiency obtained by both methods agreed very well, indicating that this thermal lens approach can be used in more complex systems where no radiative property is available. - Highlights: • Normalized Lifetime Thermal Lens was used to investigate Nd-doped samples. • Experimental setup and data analysis are simpler than in conventional techniques. • Luminescence quantum yield agrees with that obtained through standard techniques. • This approach, to obtain the quantum yield, can be extended to more complex systems.

  14. Thermal lens and all optical switching of new organometallic compound doped polyacrylamide gel

    Science.gov (United States)

    Badran, Hussain Ali

    In this work thermal lens spectrometry (TLS) is applied to investigate the thermo-optical properties of new organometallic compound containing azomethine group, Dichloro bis [2-(2-hydroxybenzylideneamino)-5-methylphenyl] telluride platinum(II), doped polyacrylamide gel using transistor-transistor logic (TTL) modulated cw 532 nm laser beam as an excitation beam modulated at 10 Hz frequency and probe beam wavelength 635 nm at 14 mW. The technique is applied to determine the thermal diffusivities, ds/dT and the linear thermal expansion coefficient of the sample. All-optical switching effects with low background and high stability are demonstrated.

  15. Thermal lens and interferometric method for glass transition and thermo physical properties measurements in Nd2O3 doped sodium zincborate glass.

    Science.gov (United States)

    Astrath, N G C; Steimacher, A; Rohling, J H; Medina, A N; Bento, A C; Baesso, M L; Jacinto, C; Catunda, T; Lima, S M; Karthikeyan, B

    2008-12-22

    In this work the time resolved thermal lens method is combined with interferometric technique, the thermal relaxation calorimetry, photoluminescence and lifetime measurements to determine the thermo physical properties of Nd(2)O(3) doped sodium zincborate glass as a function of temperature up to the glass transition region. Thermal diffusivity, thermal conductivity, fluorescence quantum efficiency, linear thermal expansion coefficient and thermal coefficient of electronic polarizability were determined. In conclusion, the results showed the ability of thermal lens and interferometric methods to perform measurements very close to the phase transition region. These techniques provide absolute values for the measured physical quantities and are advantageous when low scan rates are required.

  16. Mode-mismatched confocal thermal-lens microscope with collimated probe beam

    Energy Technology Data Exchange (ETDEWEB)

    Cabrera, Humberto, E-mail: hcabrera@ictp.it [SPIE-ICTP Anchor Research Laboratory, International Centre for Theoretical Physics (ICTP), Strada Costiera 11, Trieste (Italy); Centro Multidisciplinartio de Ciencias, Instituto Venezolano de Investigaciones Científicas (IVIC), Mérida 5101 (Venezuela, Bolivarian Republic of); Korte, Dorota; Franko, Mladen [Laboratory for Environmental Research, University of Nova Gorica, Vipavska 13, 5000 Nova Gorica (Slovenia)

    2015-05-15

    We report a thermal lens microscope (TLM) based on an optimized mode-mismatched configuration. It takes advantage of the coaxial counter propagating tightly focused excitation and collimated probe beams, instead of both focused at the sample, as it is in currently known TLM setups. A simple mathematical model that takes into account the main features of the instrument is presented. The confocal detection scheme and the introduction of highly collimated probe beam allow enhancing the versatility, limit of detection (LOD), and sensitivity of the instrument. The theory is experimentally verified measuring ethanol’s absorption coefficient at 532.8 nm. Additionally, the presented technique is applied for detection of ultra-trace amounts of Cr(III) in liquid solution. The achieved LOD is 1.3 ppb, which represents 20-fold enhancement compared to transmission mode spectrometric techniques and a 7.5-fold improvement compared to previously reported methods for Cr(III) based on thermal lens effect.

  17. Electrostatic afocal-zoom lens design using computer optimization technique

    Energy Technology Data Exchange (ETDEWEB)

    Sise, Omer, E-mail: omersise@gmail.com

    2014-12-15

    Highlights: • We describe the detailed design of a five-element electrostatic afocal-zoom lens. • The simplex optimization is used to optimize lens voltages. • The method can be applied to multi-element electrostatic lenses. - Abstract: Electron optics is the key to the successful operation of electron collision experiments where well designed electrostatic lenses are needed to drive electron beam before and after the collision. In this work, the imaging properties and aberration analysis of an electrostatic afocal-zoom lens design were investigated using a computer optimization technique. We have found a whole new range of voltage combinations that has gone unnoticed until now. A full range of voltage ratios and spherical and chromatic aberration coefficients were systematically analyzed with a range of magnifications between 0.3 and 3.2. The grid-shadow evaluation was also employed to show the effect of spherical aberration. The technique is found to be useful for searching the optimal configuration in a multi-element lens system.

  18. Thermal measurements and inverse techniques

    CERN Document Server

    Orlande, Helcio RB; Maillet, Denis; Cotta, Renato M

    2011-01-01

    With its uncommon presentation of instructional material regarding mathematical modeling, measurements, and solution of inverse problems, Thermal Measurements and Inverse Techniques is a one-stop reference for those dealing with various aspects of heat transfer. Progress in mathematical modeling of complex industrial and environmental systems has enabled numerical simulations of most physical phenomena. In addition, recent advances in thermal instrumentation and heat transfer modeling have improved experimental procedures and indirect measurements for heat transfer research of both natural phe

  19. Flanged Intrascleral Intraocular Lens Fixation with Double-Needle Technique.

    Science.gov (United States)

    Yamane, Shin; Sato, Shimpei; Maruyama-Inoue, Maiko; Kadonosono, Kazuaki

    2017-08-01

    To report the clinical outcomes of a new technique for transconjunctival intrascleral fixation of an intraocular lens (IOL). Prospective, noncomparative, interventional case series. One hundred eyes of 97 consecutive patients with aphakia, dislocated IOL, or subluxated crystalline lens who underwent posterior chamber sutureless implantation of an IOL were studied. Two angled incisions parallel to the limbus were made by 30-gauge thin-wall needles. Haptics of an IOL were externalized with the needles and cauterized to make a flange of the haptics. The flange of the haptics were pushed back and fixed into the scleral tunnels. Best-corrected visual acuity (VA), corneal endothelial cell density, IOL tilt, and complications were determined. The IOLs were fixed with exact centration and axial stability. The mean preoperative best-corrected VA was 0.25 logarithm of the minimum angle of resolution (logMAR) units; after surgery, it improved significantly to 0.11 logMAR, 0.09 logMAR, 0.12 logMAR, and 0.04 logMAR at 6, 12, 24, and 36 months, respectively (P IOL tilt was 3.4°±2.5°. The postoperative complications included iris capture by the IOL in 8 eyes (8%), vitreous hemorrhage in 5 eyes (5%), and cystoid macular edema in 1 eye (1%). There were no incidents of postoperative retinal detachment, endophthalmitis, or IOL dislocation. We have developed a new technique for intrascleral IOL fixation. The flanged IOL fixation technique is a simple and minimally invasive method for achieving good IOL fixation with firm haptic fixation. Copyright © 2017 American Academy of Ophthalmology. Published by Elsevier Inc. All rights reserved.

  20. Chip-carrier thermal barrier and its impact on lateral thermal lens profile and beam parameter product in high power broad area lasers

    Science.gov (United States)

    Rieprich, J.; Winterfeldt, M.; Kernke, R.; Tomm, J. W.; Crump, P.

    2018-03-01

    High power broad area diode lasers with high optical power density in a small focus spot are in strong commercial demand. For this purpose, the beam quality, quantified via the beam parameter product (BPP), has to be improved. Previous studies have shown that the BPP is strongly affected by current-induced heating and the associated thermal lens formed within the laser stripe. However, the chip structure and module-assembly related factors that regulate the size and the shape of the thermal lens are not well known. An experimental infrared thermographic technique is used to quantify the thermal lens profile in diode lasers operating at an emission wavelength of 910 nm, and the results are compared with finite element method simulations. The analysis indicates that the measured thermal profiles can best be explained when a thermal barrier is introduced between the chip and the carrier, which is shown to have a substantial impact on the BPP and the thermal resistance. Comparable results are observed in further measurements of samples from multiple vendors, and the barrier is only observed for junction-down (p-down) mounting, consistent with the barrier being associated with the GaAs-metal transition.

  1. The neutron silicon lens. An update of the thermal neutron lens results

    International Nuclear Information System (INIS)

    Johnson, M.W.; Daymond, M.R.

    2001-01-01

    This paper introduces the concept of the Neutron Silicon Lens (NSL) and provides and update on the experimental results achieved to date. The NSL design is a cylindrical neutron lens based on the use of multiple neutron mirrors supported and separated by silicon wafers. Such lenses would have many applications in both the primary and scattered beams on neutron instruments, and would lead to immediate improvements where the sample to be illuminated is small, as in high pressure or engineering strain scanning instruments. (author)

  2. The neutron silicon lens. An update of the thermal neutron lens results

    Energy Technology Data Exchange (ETDEWEB)

    Johnson, M.W.; Daymond, M.R. [Rutherford Appleton Laboratory, Chilton, Didcot, Oxfordshire (United Kingdom)

    2001-03-01

    This paper introduces the concept of the Neutron Silicon Lens (NSL) and provides and update on the experimental results achieved to date. The NSL design is a cylindrical neutron lens based on the use of multiple neutron mirrors supported and separated by silicon wafers. Such lenses would have many applications in both the primary and scattered beams on neutron instruments, and would lead to immediate improvements where the sample to be illuminated is small, as in high pressure or engineering strain scanning instruments. (author)

  3. Absorption coefficient of nearly transparent liquids measured using thermal lens spectrometry

    Directory of Open Access Journals (Sweden)

    H.Cabrera

    2006-01-01

    Full Text Available We use an optimized pump-probe mode-mismatched thermal lens scheme to determine the optical absorption coefficient and thermal diffusivity of ethanol, benzene, acetone, methanol, toluene and chloroform. In this scheme the excitation beam is focused in the presence of a collimated probe beam. The agreement between experimentally obtained results and values reported in the literature is good.

  4. Double-beam optical method and apparatus for measuring thermal diffusivity and other molecular dynamic processes in utilizing the transient thermal lens effect

    International Nuclear Information System (INIS)

    Gupta, A.; Hong, S.; Moacanin, J.

    1981-01-01

    A method and apparatus for measuring thermal diffusivity and molecular relaxation processes in a sample material utilizing two light beams, one being a pulsed laser light beam for forming a thermal lens in the sample material, and the other being a relatively low power probe light beam for measuring changes in the refractive index of the sample material during formation and dissipation of the thermal lens. More specifically, a sample material is irradiated by relatively high power, short pulses from a dye laser. Energy from the pulses is absorbed by the sample material, thereby forming a thermal lens in the area of absorption. The pulse repetition rate is chosen so that the thermal lens is substantially dissipated by the time the next pulse reaches the sample material. A probe light beam, which in a specific embodiment is a relatively low power, continuous wave (Cw) laser beam, irradiates the thermal lens formed in the sample material. The intensity characteristics of the probe light beam subsequent to irradiation of the thermal lens is related to changes in the refractive index of the sample material as the thermal lens is formed and dissipated. A plot of the changes in refractive index as a function of time during formation of the thermal lens as reflected by changes in intensity of the probe beam, provides a curve related to molecular relaxation characteristics of the material, and a plot during dissipation of the thermal lens provides a curve related to the thermal diffusivity of the sample material

  5. Sutureless, Glueless, Scleral Fixation of Single-Piece and Toric Intraocular Lens: A Novel Technique

    Directory of Open Access Journals (Sweden)

    Aditya Kelkar

    2015-07-01

    Full Text Available Sutureless, glueless, scleral fixation of an intraocular lens is a known technique of fixing a lens in the scleral pockets. However, this technique is applied to single-piece and toric lenses instead of 3-piece lenses, allowing the advantage of the use of premium lenses in patients with poor capsular support. Favourable results without complications of pigment dispersion, iris transillumination defects, dysphotopsia, elevated intraocular pressure, intraocular hemorrhage and cystoid macular edema with a well-centered, stable intraocular lens have been observed in the 3-month postoperative period in both cases.

  6. Thermal characterization of radiation processed contact lens material

    International Nuclear Information System (INIS)

    Varshney, L.; Choughule, S.V.

    1998-01-01

    Differential scanning calorimetry (DSC), thermomechanical analysis (TMA) and thermogravimetry analysis (TGA) were used to characterize radiation processed contact lens gel material of 2-hydroxy ethyl methacrylate(HEMA). DSC revealed two types of water in the gels. DSC and TGA in combination were used to quantitate the percentage of different types of the water in the gel material. Temperature expansion coefficients values indicate more dimensions stability in the radiation processed lenses of similar water contents. (author)

  7. The ring cycle: an iterative lens reconstruction technique applied to MG1131 + 0456

    International Nuclear Information System (INIS)

    Kochanek, C.S.; Blandford, R.D.; Lawrence, C.R.; Narayan, R.

    1989-01-01

    A new technique is described for the analysis of well-resolved gravitational lens images. This method allows us to solve for the brightness distribution of the unlensed source as well as a parametrized model of the lens. Our algorithm computes a figure of merit for a lens model based on the scatter in the surface brightnesses of image elements that, according to the model, come from the same source element. Minimization of the figure of merit leads to an optimum solution for the source and the lens. We present a successful application of the method to VLA maps of the 'Einstein ring' radio source MG1131 + 0456 observed by previous authors. The inversion gives a normal galaxy-like elliptical potential for the lens and an ordinary double-lobed structure for the background radio source. (author)

  8. Thermal Lens Spectroscopy as a 'new' analytical tool for actinide determination in nuclear reprocessing processes

    International Nuclear Information System (INIS)

    Canto, Fabrice; Couston, Laurent; Magnaldo, Alastair; Broquin, Jean-Emmanuel; Signoret, Philippe

    2008-01-01

    Thermal Lens Spectroscopy (TLS) consists of measuring the effects induced by the relaxation of molecules excited by photons. Twenty years ago, the Cea already worked on TLS. Technologic reasons impeded. But, needs in sensitive analytical methods coupled with very low sample volumes (for example, traces of Np in the COEX TM process) and also the reduction of the nuclear wastes encourage us to revisit this method thanks to the improvement of optoelectronic technologies. We can also imagine coupling TLS with micro-fluidic technologies, decreasing significantly the experiments cost. Generally two laser beams are used for TLS: one for the selective excitation by molecular absorption (inducing the thermal lens) and one for probing the thermal lens. They can be coupled with different geometries, collinear or perpendicular, depending on the application and on the laser mode. Also, many possibilities of measurement have been studied to detect the thermal lens signal: interferometry, direct intensities variations, deflection etc... In this paper, one geometrical configuration and two measurements have been theoretically evaluated. For a single photodiode detection (z-scan) the limit of detection is calculated to be near 5*10 -6 mol*L -1 for Np(IV) in dodecane. (authors)

  9. Radiation therapy for retinoblastoma: comparison of results with lens-sparing versus lateral beam techniques

    International Nuclear Information System (INIS)

    McCormick, B.; Ellsworth, R.; Abramson, D.; Haik, B.; Tome, M.; Grabowski, E.; LoSasso, T.

    1988-01-01

    From 1979 through 1986, 170 children were seen at our institution diagnosed with retinoblastoma. Sixty-six of the children with involvement of 121 eyes, were referred for definitive external beam radiation to one or both eyes. During the study period, two distinct radiation techniques were used. From 1980 through mid-1984, a lens-sparing technique included an anterior electron beam with a contact lens mounted lead shield, combined with a lateral field, was used. Since mid-1984, a modified lateral beam technique has been used, mixing lateral electrons and superior and inferior lateral oblique split beam wedged photons. Doses prescribed were similar for both techniques, ranging from 3,850 to 5,000 cGy in 4 to 5 weeks. The lens-sparing and the modified lateral techniques are compared for local control. For eyes with Group I through III disease, the lens-sparing technique resulted in local control in 33% of the eyes treated, where the modified lateral technique controlled 83% of the eyes treated (p = .006). Mean time to relapse was identical in both groups, that is 24 and 26 months respectively. Most relapses were successfully treated with further local therapy, including laser or cryosurgery, or 60Co plaques. Five eyes required enucleation following initial treatment with the lens-sparing technique, but none thus far with the lateral beam technique. For eyes with Group IV and V disease, no significant differences were found between the two techniques in terms of local control or eventual need for enucleation. With a mean follow-up time of 33 months for the entire group, the 4-year survival is 93%. Two of the 4 deaths are due to second primary tumor, and all 4 have occurred in the lens-sparing group. Because follow-up time is more limited in the lateral beam group, this is not statistically significant and direct survival comparisons are premature

  10. Near-near-infrared thermal lens spectroscopy to assess overtones and combination bands of sulfentrazone pesticide

    Science.gov (United States)

    Ventura, M.; Silva, J. R.; Andrade, L. H. C.; Scorza Júnior, R. P.; Lima, S. M.

    2018-01-01

    Thermal lens spectroscopy (TLS) in the near-near-infrared region was used to explore the absorptions of overtones and combination bands of sulfentrazone (SFZ) herbicide diluted in methanol. This spectroscopic region was chosen in order to guarantee that only thermal lens effect is noted during the experimental procedure. The results showed that it was possible to detect very low concentrations ( 2 ng/μL) of SFZ in methanol by determining its thermal diffusivity or the absorption coefficient due to the 3ν(NH) + 1δ(CH) combination band. This minimum SFZ concentration is the limit observed by chromatography method. The findings demonstrated that the TLS can be used for precise and accurate assessment of pesticides in ecosystems. Besides, the 3ν(NH) + 1δ(CH) combination band at 960 nm can be used as a marker for SFZ in methanol.

  11. Analytical analysis of solar thermal collector with glass and Fresnel lens glazing

    Science.gov (United States)

    Zulkifle, Idris; Ruslan, Mohd Hafidz Hj; Othman, Mohd Yusof Hj; Ibarahim, Zahari

    2018-04-01

    Solar thermal collector is a system that converts solar radiation to heat. The heat will raise the temperature higher than the ambient temperature. Absorber and glazing are two important components in order to increase the temperature of the collector. The thermal absorber will release heat by convection and as radiation to the surrounding. These losses will be reduced by glazing. Other than that, glazing is beneficial for protecting the collector from dust and water. This study discusses about modelling of solar thermal collector effects of different mass flow rates with different glazing for V-groove flat plate solar collectors. The glazing used was the glass and linear Fresnel lens. Concentration ratio in this modelling was 1.3 for 0.1m solar collector thickness. Results show that solar collectors with linear Fresnel lens has the highest efficiency value of 71.18% compared to solar collectors with glass which has efficiency 54.10% with same operation conditions.

  12. Pigment dispersion syndrome associated with intraocular lens implantation: a new surgical technique.

    Science.gov (United States)

    Canut Jordana, M Isabel; Pérez Formigó, Daniel; Abreu González, Rodrigo; Nadal Reus, Jeroni

    2010-11-11

    We report the case of a myopic patient who, after intraocular lens transplant in the posterior chamber, suffered elevated intraocular pressure due to pigment dispersion, with recurrent episodes of blurred vision. The patient was treated with a new surgical technique that can avoid potential iridolenticular contact. Complete ophthalmologic examination and optical coherence tomography (OCT) of the anterior segment were performed. Contact between the pigmentary epithelium and the iris with an intraocular lens was revealed by utrasound biomicroscopy and OCT. In this case, Nd:YAG laser iridotomy and laser iridoplasty were not effective for iridolenticular separation and control of the pigment dispersion. We propose a new technique: stitches on the surface of the iris to obtain good iridolenticular separation and good intraocular pressure control. Stitches on the iris surface should be considered as optional therapy in pigmentary glaucoma secondary to intraocular lens implantation. This surgical technique can avoid potential iridolenticular contacts more definitively.

  13. Thermal lens study of thermo-optical properties and concentration quenching of Er3+-doped lead pyrophosphate based glasses

    Energy Technology Data Exchange (ETDEWEB)

    Santos, C. C. [Universidade Federal do Ceara, Ceara, Brazil; Rocha, U. [Grupo de Fotônica e Fluidos Complexos, Instituto de Física, Brazil; Guedes, Ilde [Universidade Federal do Ceara, Ceara, Brazil; Vermelho, M. V. D. [Instituto de Fisica, Universidade Federal de Alagoas, Brazil; Boatner, Lynn A [ORNL; Jacinto, C. [Instituto de Fisica, Universidade Federal de Alagoas, Brazil

    2012-01-01

    In this work, we have used the thermal lens technique combined with conventional spectroscopy to characterize the thermo-optical properties of Er3+-doped lead pyrophosphate-based glasses. More precisely, we have investigated and quantified experimentally the fluorescence quantum efficiencies of the Er3+ levels, and we describe the role of concentration quenching effects. The fluorescence quantum efficiency of the 4I13/2 level is very high when compared to other phosphate glasses, while that of the green-coupled levels is very small. Other important photonic materials parameters, such as the thermal diffusivity and temperature coefficient of the optical path length change, were obtained and compared with those of other glass systems. The cumulative results obtained here for the Er-doped lead pyrophosphate glass show that this material is a good candidate for photonic applications with a characteristic Er3+ infrared emission around 1550 nm.

  14. Simple technique to treat pupillary capture after transscleral fixation of intraocular lens.

    Science.gov (United States)

    Jürgens, Ignasi; Rey, Amanda

    2015-01-01

    We describe a simple surgical technique to manage pupillary capture after previous transscleral fixation of an intraocular lens. Neither author has a financial or proprietary interest in any material or method mentioned. Copyright © 2015 ASCRS and ESCRS. Published by Elsevier Inc. All rights reserved.

  15. A new technique for the closure of the lens capsule by laser welding.

    Science.gov (United States)

    Pini, Roberto; Rossi, Francesca; Menabuoni, Luca; Lenzetti, Ivo; Yoo, Sonia; Parel, Jean-Marie

    2008-01-01

    A new method is presented for the closure of the lens capsule based on laser welding of suitably prepared patches of anterior capsular tissue. Experiments were performed in freshly enucleated porcine eyes. The patches were previously stained with a solution of indocyanine green in sterile water and then welded on the recipient capsule by means of diode laser radiation at 810 nm. The welded tissue revealed mechanical properties comparable to those of healthy tissue. This technique is proposed to repair capsular breaks and to provide the closure of the capsulorhexis in lens refilling procedures.

  16. Pigment dispersion syndrome associated with intraocular lens implantation: a new surgical technique

    Directory of Open Access Journals (Sweden)

    M Isabel Canut Jordana

    2010-11-01

    Full Text Available M Isabel Canut Jordana1, Daniel Pérez Formigó1, Rodrigo Abreu González2, Jeroni Nadal Reus11Barraquer Ophthalmology Centre, Barcelona, Spain; 2University Hospital of La Candelaria, Tenerife, SpainAims: We report the case of a myopic patient who, after intraocular lens transplant in the posterior chamber, suffered elevated intraocular pressure due to pigment dispersion, with recurrent episodes of blurred vision. The patient was treated with a new surgical technique that can avoid potential iridolenticular contact.Methods: Complete ophthalmologic examination and optical coherence tomography (OCT of the anterior segment were performed.Results: Contact between the pigmentary epithelium and the iris with an intraocular lens was revealed by utrasound biomicroscopy and OCT. In this case, Nd:YAG laser iridotomy and laser iridoplasty were not effective for iridolenticular separation and control of the pigment dispersion. We propose a new technique: stitches on the surface of the iris to obtain good iridolenticular separation and good intraocular pressure control.Conclusion: Stitches on the iris surface should be considered as optional therapy in pigmentary glaucoma secondary to intraocular lens implantation. This surgical technique can avoid potential iridolenticular contacts more definitively.Keywords: pigmentary glaucoma, intraocular lens, optical coherence tomography, laser

  17. DEVICE FOR MEASURING OF THERMAL LENS PARAMETERS IN LASER ACTIVE ELEMENTS WITH A PROBE BEAM METHOD

    Directory of Open Access Journals (Sweden)

    A. N. Zakharova

    2015-01-01

    Full Text Available We have developed a device for measuring of parameters of thermal lens (TL in laser active elements under longitudinal diode pumping. The measurements are based on the probe beam method. This device allows one to determine sign and optical power of the lens in the principal meridional planes, its sensitivity factor with respect to the absorbed pump power and astigmatism degree, fractional heat loading which make it possible to estimate integral impact of the photoelastic effect to the formation of TL in the laser element. The measurements are performed in a linearly polarized light at the wavelength of 532 nm. Pumping of the laser element is performed at 960 nm that makes it possible to study laser materials doped with Yb3+ and (Er3+, Yb3+ ions. The precision of measurements: for sensitivity factor of TL – 0,1 m-1/W, for astigmatism degree – 0,2 m-1/W, for fractional heat loading – 5 %, for the impact of the photoelastic effect – 0,5 × 10-6 K-1. This device is used for characterization of thermal lens in the laser active element from an yttrium vanadate crystal, Er3+,Yb3+:YVO .

  18. Stop grating for perfect replication of micro Fresnel lens by thermal imprinting

    International Nuclear Information System (INIS)

    Gao, Yulong; Lin, Jie; Jin, Peng; Tan, Jiubin; Davies, Graham; Prewett, Philip D

    2012-01-01

    A stop grating concept is proposed to improve polymer filling in the thermal imprinting of a micro Fresnel lens structure. The stop grating consists of line and space structures outside the Fresnel lens pattern zone area. The experimental results have proved that the stop grating can help to achieve the complete filling of a mold, at the same time acting as a stop to prevent possible damage to the mold surface relief structures during imprinting press. A computer simulation was carried out to identify the phenomena of micro-holes at the edge of imprinted pattern. By removing the cavity between the pattern area and stop grating, perfect imprinting results have been achieved. (paper)

  19. The Application of Globular Water-Atomized Iron Powders for Additive Manufacturing by a LENS Technique.

    Science.gov (United States)

    Durejko, Tomasz; Aniszewska, Justyna; Ziętala, Michał; Antolak-Dudka, Anna; Czujko, Tomasz; Varin, Robert A; Paserin, Vlad

    2018-05-18

    The water-atomized ATOMET 28, 1001, 4701, and 4801 powders, manufactured by Rio Tinto Metal Powders, were used for additive manufacturing by a laser engineered net shaping (LENS) technique. Their overall morphology was globular and rounded with a size distribution from about 20 to 200 µm. Only the ATOMET 28 powder was characterized by a strong inhomogeneity of particle size and irregular polyhedral shape of powder particles with sharp edges. The powders were pre-sieved to a size distribution from 40 to 150 µm before LENS processing. One particular sample-LENS-fabricated from the ATOMET 28 powder-was characterized by the largest cross-sectional (2D) porosity of 4.2% and bulk porosity of 3.9%, the latter determined by microtomography measurements. In contrast, the cross-sectional porosities of bulk, solid, nearly cubic LENS-fabricated samples from the other ATOMET powders exhibited very low porosities within the range 0.03⁻0.1%. Unexpectedly, the solid sample-LENS-fabricated from the reference, a purely spherical Fe 99.8 powder-exhibited a porosity of 1.1%, the second largest after that of the pre-sieved, nonspherical ATOMET 28 powder. Vibrations incorporated mechanically into the LENS powder feeding system substantially improved the flow rate vs. feeding rate dependence, making it completely linear with an excellent coefficient of fit, R² = 0.99. In comparison, the reference powder Fe 99.8 always exhibited a linear dependence of the powder flow rate vs. feeding rate, regardless of vibrations.

  20. Evaluate depth of field limits of fixed focus lens arrangements in thermal infrared

    Science.gov (United States)

    Schuster, Norbert

    2016-05-01

    More and more modern thermal imaging systems use uncooled detectors. High volume applications work with detectors that have a reduced pixel count (typically between 200x150 and 640x480). This reduces the usefulness of modern image treatment procedures such as wave front coding. On the other hand, uncooled detectors demand lenses with fast fnumbers, near f/1.0, which reduces the expected Depth of Field (DoF). What are the limits on resolution if the target changes distance to the camera system? The desire to implement lens arrangements without a focusing mechanism demands a deeper quantification of the DoF problem. A new approach avoids the classic "accepted image blur circle" and quantifies the expected DoF by the Through Focus MTF of the lens. This function is defined for a certain spatial frequency that provides a straightforward relation to the pixel pitch of imaging device. A certain minimum MTF-level is necessary so that the complete thermal imaging system can realize its basic functions, such as recognition or detection of specified targets. Very often, this technical tradeoff is approved with a certain lens. But what is the impact of changing the lens for one with a different focal length? Narrow field lenses, which give more details of targets in longer distances, tighten the DoF problem. A first orientation is given by the hyperfocal distance. It depends in a square relation on the focal length and in a linear relation on the through focus MTF of the lens. The analysis of these relations shows the contradicting requirements between higher thermal and spatial resolution, faster f-number and desired DoF. Furthermore, the hyperfocal distance defines the DoF-borders. Their relation between is such as the first order imaging formulas. A calculation methodology will be presented to transfer DoF-results from an approved combination lens and camera to another lens in combination with the initial camera. Necessary input for this prediction is the accepted DoF of

  1. The effect of a transient thermal lens on the Nd:YVO4 laser output

    International Nuclear Information System (INIS)

    Yi, Jonghoon; Lee, Kangin; Kim, Youngjung; Kwon, Jinhyuk

    2010-01-01

    A Nd:YVO 4 laser was pumped by using a diode laser, which has maximum cw pump power of 1 W. The driving current of the diode laser was modulated to have a square waveform. The Nd:YVO 4 laser output power increased linearly and then saturated when the quasi-cw diode laser pulse was focused on the crystal. When the same diode laser pulse was applied on the crystal, transient thermal lensing in the Nd:YVO 4 crystal was monitored by using a probe beam in a non-lasing condition. The TEM 00 mode diameter of the laser was calculated as a function of the focal length of the thermal lens. The results indicated that transient thermal lensing in the crystal was the main cause of the temporally varying output.

  2. A pH dependence study of CdTe quantum dots fluorescence quantum yields using eclipsing thermal lens spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Estupiñán-López, C. [Laboratory of Biomedical Optics and Imaging, Federal University of Pernambuco, Recife, PE (Brazil); Dominguez, C. Tolentino [Laboratory of Biomedical Optics and Imaging, Federal University of Pernambuco, Recife, PE (Brazil); Centre for Telecommunication Studies, Pontifical Catholic University of Rio de Janeiro, Rio de Janeiro, RJ (Brazil); Filho, P.E. Cabral [Laboratory of Biomedical Optics and Imaging, Federal University of Pernambuco, Recife, PE (Brazil); Biophysics and Radiobiology Department, Federal University of Pernambuco, Recife, PE (Brazil); Santos, B.S. [Laboratory of Biomedical Optics and Imaging, Federal University of Pernambuco, Recife, PE (Brazil); Pharmaceutical Sciences Department, Federal University of Pernambuco, Recife, PE (Brazil); Fontes, A., E-mail: adriana.fontes.biofisica@gmail.com [Laboratory of Biomedical Optics and Imaging, Federal University of Pernambuco, Recife, PE (Brazil); Biophysics and Radiobiology Department, Federal University of Pernambuco, Recife, PE (Brazil); Araujo, R.E. de, E-mail: renato.earaujo@ufpe.br [Laboratory of Biomedical Optics and Imaging, Federal University of Pernambuco, Recife, PE (Brazil)

    2016-06-15

    In this study we evaluated the absolute fluorescence quantum yield (Φ) of hydrophilic CdTe QDs in function of different pHs, modified from the alkaline to acid, by using two different chemicals compounds, the mercaptosuccinic acid (MSA-the stabilizing agent of the QDs synthesis) or hydrochloric acid (HCl). The pH control of QDs suspensions is essential for the use of fluorescent nanoparticles in biological systems. We used the eclipsing thermal lens spectroscopy technique to determine the absolute fluorescence quantum yield values. The results showed variations on the Φ values as a function of the pH, which allowed a better understanding of QDs emission characteristics, establishing parameters for their use in biomedical applications such as optical images of biological systems, immunoassays, flow cytometry, biosensors and others.

  3. A simple lens-sparing technique to treat hypotonic maculopathy secondary to large cyclodialysis

    OpenAIRE

    Masayo Kimura; Tsutomu Yasukawa; Yuichiro Ogura

    2018-01-01

    Purpose: Hypotonic maculopathy secondary to cyclodialysis often persists and causes irreversible visual loss despite a variety of treatments proposed. The purpose of this study is to report two cases with persistent hypotonic maculopathy due to a large cyclodialysis cleft treated with a simple, lens-sparing technique of external drainage, diathermy, and suturing under the placement of an infusion cannula. Observations: Both patients had sustained blunt trauma to one eye, causing persisting hy...

  4. Two-step technique for posterior optic buttonholing of intraocular lens.

    Science.gov (United States)

    Agarwal, Tushar; Jhanji, Vishal; Singh, Digvijay; Khokhar, Sudarshan

    2014-04-01

    This study aims to describe a two-step surgical technique for placement of a posterior chamber intraocular lens (IOL) in cases with crystalline lens subluxation resulting from non-progressive zonular dialysis. The first stage entails a phacoemulsification with creation of a 4-mm posterior capsular opening using an automated vitrector. The second stage performed 6 weeks later includes an anterior vitrectomy and injection of a foldable three-piece IOL in the sulcus. The haptics of IOL are positioned in the sulcus while the optic is pushed behind the posterior capsular opening therefore "buttonholing" the IOL. Seven eyes of seven patients with posttraumatic zonular dialysis were operated using this technique. Follow-up of all cases revealed a well-centered IOL with good postoperative visual acuity (20/20 to 20/80). Our two-stage surgical technique precludes the insertion of capsular tension ring in cases with non-progressive zonular dialysis. The technique is recommended in the presence of less than or equal to 6 clock hours of zonular dialysis with preexisting posterior capsular tear or herniation of vitreous in the anterior chamber.

  5. Net technique for intraocular lens support in aphakia without capsular support.

    Science.gov (United States)

    De Novelli, Fernando José; Neto, Theodomiro Lourenço Garrido; de Sena Rabelo, Gabriel; Blumer, Marcel Eduardo; Suzuki, Ricardo; Ghanem, Ramon Coral

    2017-01-01

    This paper describes a modified surgical technique for intraocular lens implantation in aphakic eyes with no capsular support. Retrospective case series. Seventeen eyes of 17 aphakic patients with no capsule support underwent intraocular lens (IOL) implantation using a standardized technique in which a net was created at the ciliary sulcus plane with two threads forming a net pattern. The net was used as support for the IOL. Follow-up ranged from 6 to 38 months, with an average of 23 months. In all cases, the IOL was safely implanted and remained stable during the follow-up. In 16 eyes, the IOL remained well centered; in one eye, slight decentration was observed. Distance-corrected visual acuity improved by a mean of 4 lines, from 1.13 (LogMAR) to 0.52 (P = 0.01). This technique might be especially useful in cases of insufficient capsular support associated with tissue loss or iris atrophy. In these cases, iris fixation is not feasible; thus, the only surgical alternative is IOL scleral fixation.

  6. Thermal property testing technique on micro specimen

    International Nuclear Information System (INIS)

    Baba, Tetsuya; Kishimoto, Isao; Taketoshi, Naoyuki

    2000-01-01

    This study aims at establishment of further development on some testing techniques on the nuclear advanced basic research accumulated by the National Research Laboratory of Metrology for ten years. For this purpose, a technology to test heat diffusion ratio and specific heat capacity of less than 3 mm in diameter and 1 mm in thickness of micro specimen and technology to test heat diffusion ratio at micro area of less than 1 mm in area along cross section of less than 10 mm in diameter of column specimen were developed to contribute to common basic technology supporting the nuclear power field. As a result, as an element technology to test heat diffusion ratio and specific heat capacity of the micro specimen, a specimen holding technique stably to hold a micro specimen with 3 mm in diameter could be developed. And, for testing the specific heat capacity by using the laser flush differential calorimetry, a technique to hold two specimen of 5 mm in diameter at their proximities was also developed. In addition, by promoting development of thermal property data base capable of storing thermal property data obtained in this study and with excellent workability in this 1998 fiscal year a data in/out-put program with graphical user interface could be prepared. (G.K.)

  7. A modified-simple technique of removing the lens cortex during cataract surgery

    Directory of Open Access Journals (Sweden)

    Kyung Eun Han

    2017-01-01

    Full Text Available We describe here a surgical technique of removing the remaining cortex after phacoemulsification without performing the conventional irrigation/aspiration (I/A procedure. In this technique, the remaining cortex attached to the posterior capsule was separated and dissected into several pieces by continuous irrigation with balanced salt solution, which was supplied through a syringe attached to a bent, blunt-tip needle. Approximately, 10 s of manual irrigation separated most of the remaining cortex from the posterior capsule. Then, the capsular bag was inflated with an ophthalmic viscoelastic device (OVD, and this pushed the separated cortex toward the capsular fornix mechanically. An intraocular lens was inserted into the capsular bag, following which the remaining cortex and OVD were removed concomitantly using an automated I/A handpiece. This technique is a simple and easy maneuver to remove the cortex from all areas, including the subincisional area, and reduce the possibility of a posterior capsule tear.

  8. Lens sparing technique using multi-leaf collimators in irradiation of the unilateral retro-orbital space for benign disease

    International Nuclear Information System (INIS)

    Middleton, Mark; Medwell, Stephen; Bennie, David; Fogarty, Gerald

    2005-01-01

    The authors present a case of a 30-year-old woman with pseudolymphoma of the left medial rectus muscle. A multi-field technique was planned for irradiating the unilateral retro-orbital space to 20 Gray (GY) in 15 fractions while keeping the average dose to the lens of 8 Gy and the peak dose to the lens of 11 Gy using multi-leaf collimators is described. Copyright (2005) Australian Institute of Radiography

  9. Thermal and ghost reflection modeling for a 180-deg. field-of-view long-wave infrared lens

    Science.gov (United States)

    Shi, Weimin; Couture, Michael E.

    2001-03-01

    Optics 1, Inc. has successfully designed and developed a 180 degree(s) field of view long wave infrared lens for USAF/AFRL under SBIR phase I and II funded projects in support of the multi-national Programmable Integrated Ordinance Suite (PIOS) program. In this paper, a procedure is presented on how to evaluate image degradation caused by asymmetric aerodynamic dome heating. In addition, a thermal gradient model is proposed to evaluate degradation caused by axial temperature gradient throughout the entire PIOS lens. Finally, a ghost reflection analysis is demonstrated with non-sequential model.

  10. Gamma and x radiation and thermal neutrons effects in lens solutions and the relation with proteins concentration

    International Nuclear Information System (INIS)

    Ramirez A, M.; Alarcon C, A.

    1996-01-01

    Radiation effects have been studied irradiating porcine lens solutions with doses which range between 52 Gy to 1042 Gy in the case of x-rays (30 kVp), 631 Gy to 4001 Gy in the case of 60 Co gamma rays and 314 Gy to 7596 Gy for thermal neutrons. The optics density time variation of solutions was determined using a Spectronic-501 spectrophotometer, and with this data an equation which describes the behavior in the mentioned cases was found. A phenomenological model is postulated which connects the optical time variation density increment macroscopic effect with proteins concentration in the crystalline lens obtaining relative biological effectiveness using the supra-molecular aggregate formation due to the denaturalization and destruction of lens proteins by radiation criteria. (authors). 5 refs., 3 figs

  11. Biaxial-Type Concentrated Solar Tracking System with a Fresnel Lens for Solar-Thermal Applications

    Directory of Open Access Journals (Sweden)

    Tsung Chieh Cheng

    2016-04-01

    Full Text Available In this paper, an electromechanical, biaxial-type concentrated solar tracking system was designed for solar-thermal applications. In our tracking system, the sunlight was concentrated by the microstructure of Fresnel lens to the heating head of the Stirling engine and two solar cells were installed to provide the power for tracking system operation. In order to obtain the maximum sun power, the tracking system traces the sun with the altitude-azimuth biaxial tracing method and accurately maintains the sun’s radiation perpendicular to the plane of the heating head. The results indicated that the position of heating head is an important factor for power collection. If the sunlight can be concentrated to completely cover the heating head with small heat loss, we can obtain the maximum temperature of the heating head of the Stirling engine. Therefore, the temperature of heating head can be higher than 1000 °C in our experiment on a sunny day. Moreover, the results also revealed that the temperature decrease of the heating head is less than the power decrease of solar irradiation because of the latent heat of copper and the small heat loss from the heating head.

  12. Determination of molybdenum in natural waters by laser thermal-lens spectrometry

    International Nuclear Information System (INIS)

    Proskurnin, M.A.; Abroskin, A.G.; Artemova, S.I.; Belyaeva, T.V.; Ivanova, E.K.

    1992-01-01

    As before, the determination of nanogram quantities of heavy metals from small sample volumes of natural water represents an acute problem. This task has been solved more or less successfully by the use of different and sufficiently developed physicochemical methods. In most cases the determination requires a 100-fold preconcentration of the component determined (for instance, when using atomic absorption spectrometry). This significant disadvantage can be avoided by the use of thermal-lens laser spectrometry (TLS); some alternatives of the method have already found applications in analytical practice. The objective of the present study has been to investigate the optimum conditions for the determination of molybdenum in natural waters from small sample volumes by TLS. The resulting method based on the reaction with thiocyanate ions in the presence of ascorbic acid, has a detection limit of 19 pg/ml. Masking of iron(III) with a 1000-fold excess of tartrate ions has been proposed and it has been shown that a 10-fold excess of iron does not interfere in the determination of molybdenum. The procedure has been applied to the determination of molybdenum in drinking and natural waters

  13. Laboratory technique for quantitative thermal emissivity ...

    Indian Academy of Sciences (India)

    Emission of radiation from a sample occurs due to thermal vibration of its .... Quantitative thermal emissivity measurements of geological samples. 393. Figure 1. ...... tral mixture modeling: A new analysis of rock and soil types at the Viking ...

  14. Assessment of phacoaspiration techniques in clear lens extraction for correction of high myopia

    Directory of Open Access Journals (Sweden)

    Mostafa A El-Helw

    2010-03-01

    Full Text Available Mostafa A El-Helw, Ahmed M EmarahDepartment of Ophthalmology, Cairo University, EgyptPurpose: To evaluate various phacoaspiration techniques in clear lens extraction for the incidence of intraoperative difficulties and complications.Patients and methods: This was a prospective study in which bilateral clear lens extraction was performed on 40 eyes of 20 patients, to correct high myopia. The patients were divided into 2 groups: group A underwent supracapsular phacoaspiration; group B were the contralateral eyes of the same patient. These patients were operated on with endocapsular phacoaspiration with the divide and conquer (D and C technique. Preoperative ocular examination data were recorded and tested for significance. Intraoperative difficulties and complications such as nucleus cracking, capsule rupture and vitreous loss, and repeated chamber collapse were recorded. Postoperative examination data were recorded.Results: Mean age was 35.65 ± 5.85 years. Mean follow-up time was 17.1 ± 8.56 months. In group A mean myopia was -17.3 ± 5.07 diopters; in group B myopia was -17.9 ± 4.20 diopters. Mean preoperative uncorrected visual acuity (UCVA was 0.04 ± 0.0167, while the mean postoperative UCVA was 0.435 ± 0.1442. There was a significant difference in pre and postoperative BCVA within both groups, but not between the two groups. In both groups endothelial cell count (ECC showed a significant difference between pre- and postoperative data; however, there was no statistically significant difference between both groups in postoperative ECC. The effective phacoaspiration time for group A was 4.6 ± 1.6 seconds, and for group B 9.90 ± 2.27 seconds (P < 0.005. No cases of capsule rupture occurred in group A, but 3 cases occurred in group B (15 % (not significant, P = 0.231. Nucleus cracking did not occur in group A, but in group B 13 cases occurred (65%. Chamber collapse occurred in 4 cases (20% in group A and 5 cases (25% in group B (not

  15. Thermal cycling fatigue of organic thermal interface materials using a thermal-displacement measurement technique

    Science.gov (United States)

    Steill, Jason Scott

    The long term reliability of polymer-based thermal interface materials (TIM) is essential for modern electronic packages which require robust thermal management. The challenge for today's materials scientists and engineers is to maximize the heat flow from integrated circuits through a TIM and out the heat sink. Thermal cycling of the electronic package and non-uniformity in the heat flux with respect to the plan area can lead to void formation and delamination which re-introduces inefficient heat transfer. Measurement and understanding at the nano-scale is essential for TIM development. Finding and documenting the evolution of the defects is dependent upon a full understanding of the thermal probes response to changing environmental conditions and the effects of probe usage. The response of the thermal-displacement measurement technique was dominated by changes to the environment. Accurate measurement of the thermal performance was hindered by the inability to create a model system and control the operating conditions. This research highlights the need for continued study into the probe's thermal and mechanical response using tightly controlled test conditions.

  16. Crossed-swords, capsule-pinch technique for capsulotomy in pediatric and/or loose lens cataract extraction.

    Science.gov (United States)

    Snyder, Michael E; Lindsell, Luke B

    2010-02-01

    Puncturing the anterior capsule in a patient with a very soft lens, an elastic capsule, and/or deficient zonular countertraction can be challenging even with a sharp needle or blade. The crossed-swords, capsule-pinch technique capitalizes on opposing forces from 2 needles directed toward each other with a "pinch" of the capsule between their tips. This affords a controlled and facile puncture of the capsule without creating stress on the zonules or anteroposterior displacement of the lens. Copyright 2010 ASCRS and ESCRS. Published by Elsevier Inc. All rights reserved.

  17. More accurate thermal neutron coincidence counting technique

    International Nuclear Information System (INIS)

    Baron, N.

    1978-01-01

    Using passive thermal neutron coincidence counting techniques, the accuracy of nondestructive assays of fertile material can be improved significantly using a two-ring detector. It was shown how the use of a function of the coincidence count rate ring-ratio can provide a detector response rate that is independent of variations in neutron detection efficiency caused by varying sample moderation. Furthermore, the correction for multiplication caused by SF- and (α,n)-neutrons is shown to be separable into the product of a function of the effective mass of 240 Pu (plutonium correction) and a function of the (α,n) reaction probability (matrix correction). The matrix correction is described by a function of the singles count rate ring-ratio. This correction factor is empirically observed to be identical for any combination of PuO 2 powder and matrix materials SiO 2 and MgO because of the similar relation of the (α,n)-Q value and (α,n)-reaction cross section among these matrix nuclei. However the matrix correction expression is expected to be different for matrix materials such as Na, Al, and/or Li. Nevertheless, it should be recognized that for comparison measurements among samples of similar matrix content, it is expected that some function of the singles count rate ring-ratio can be defined to account for variations in the matrix correction due to differences in the intimacy of mixture among the samples. Furthermore the magnitude of this singles count rate ring-ratio serves to identify the contaminant generating the (α,n)-neutrons. Such information is useful in process control

  18. Evaluation of different surgical techniques in the management of subluxated cataractous lens.

    Science.gov (United States)

    Aldakaf, A; Bakir, H; Almogahed, A; Carstocea, Benone

    2007-01-01

    To compare and evaluate the outcome of different surgical techniques in the management of subluxated cataractous lens. This retrospective study included 18 eyes of 18 patients with subluxated cataracts of varying etiology. Their preoperative examination maintain included: best corrected visual acuity (BCVA), thorough anterior segment examination, by slit -lamp especially for the degree and extent of subluxation and cataract, cornea, iris and the pupil for other abnormalities or other traumatic signs, presence or absence of vitreous in the anterior chamber, IOP and finally fundus examination. The patients were then divided into 3 groups each comprising 6 patients. The first group underwent ECCE with sulcus implantation PMMA IOL , the second and third groups underwent phacoemulsification with bag implanted Acrylic IOL but the third group underwent special techniques and precautions during surgery. Postoperatively, all patients were examined for BCVA, IOP, IOL positioning, pupil, fundus examination. Thirteen patients were males and five were females. The etiology of subluxation was traumatic in ten males and two female. The ages of the patients were between 11 and 62 years old the post operative follow up period ranged between 7 and 16 months. No major intraoperative complications were noted. In the 1st group 2 patients underwent AC automated vitrectomy, 3 in the 2nd group, 1 in the 3rd group. Three patients needed scleral fixation suture . Thirteen patients had well centered IOL and 4 had slight decentration not necessitating further intervention and one in the 2nd group had clinically significant decentration where IOL explanation, widening of the wound and re implantation of a wide 6.5mm optic PMMA IOL was done in the second post operative daily. Subluxated cataracts need special precautions in the chosen surgical technique to maintain a reasonable safety level intraoperatively and an acceptable surgical.

  19. Characteristics of Laser Flash Technique for Thermal Diffusivity Measurement

    Energy Technology Data Exchange (ETDEWEB)

    Park, D. G.; Kim, H. M.; Hong, G. P

    2008-08-15

    In relation to selection of thermal conductivity measurement technology, various thermal conductivity measurement technique are investigated for characteristics of each technique and it's measurable range. For the related laser flash techniques, various technical characteristics are reviewed and discussed. Especially, Parker adiabatic model are reviewed because of importance for basic theory of the thermal diffusivity determination. Finite pulse time effect, heat loss effect and non-uniform heating effect, which are main technical factors for laser flash technique, are considered. Finally, characteristics of constituent elements for laser flash measurement system are reviewed and investigated in detail.

  20. Thermal diffusivity of diamond films using a laser pulse technique

    International Nuclear Information System (INIS)

    Albin, S.; Winfree, W.P.; Crews, B.S.

    1990-01-01

    Polycrystalline diamond films were deposited using a microwave plasma-enhanced chemical vapor deposition process. A laser pulse technique was developed to measure the thermal diffusivity of diamond films deposited on a silicon substrate. The effective thermal diffusivity of a diamond film on silicon was measured by observing the phase and amplitude of the cyclic thermal waves generated by laser pulses. An analytical model is presented to calculate the effective inplane (face-parallel) diffusivity of a two-layer system. The model is used to reduce the effective thermal diffusivity of the diamond/silicon sample to a value for the thermal diffusivity and conductivity of the diamond film

  1. Segmentation techniques for extracting humans from thermal images

    CSIR Research Space (South Africa)

    Dickens, JS

    2011-11-01

    Full Text Available A pedestrian detection system for underground mine vehicles is being developed that requires the segmentation of people from thermal images in underground mine tunnels. A number of thresholding techniques are outlined and their performance on a...

  2. Metallographic techniques for evaluation of thermal barrier coatings

    Science.gov (United States)

    Brindley, William J.; Leonhardt, Todd A.

    1990-01-01

    The performance of ceramic thermal barrier coatings is strongly dependent on the amount and shape of the porosity in the coating. Current metallographic techniques do not provide polished surfaces that are adequate for a repeatable interpretation of the coating structures. A technique recently developed at NASA-Lewis for preparation of thermal barrier coating sections combines epoxy impregnation, careful sectioning and polishing, and interference layering to provide previously unobtainable information on processing-induced porosity. In fact, increased contrast and less ambiguous structure developed by the method make automatic quantitative metallography a viable option for characterizing thermal barrier coating structures.

  3. Thermal Characterization of Edible Oils by Using Photopyroelectric Technique

    Science.gov (United States)

    Lara-Hernández, G.; Suaste-Gómez, E.; Cruz-Orea, A.; Mendoza-Alvarez, J. G.; Sánchez-Sinéncio, F.; Valcárcel, J. P.; García-Quiroz, A.

    2013-05-01

    Thermal properties of several edible oils such as olive, sesame, and grape seed oils were obtained by using the photopyroelectric technique. The inverse photopyroelectric configuration was used in order to obtain the thermal effusivity of the oil samples. The theoretical equation for the photopyroelectric signal in this configuration, as a function of the incident light modulation frequency, was fitted to the experimental data in order to obtain the thermal effusivity of these samples. Also, the back photopyroelectric configuration was used to obtain the thermal diffusivity of these oils; this thermal parameter was obtained by fitting the theoretical equation for this configuration, as a function of the sample thickness (called the thermal wave resonator cavity), to the experimental data. All measurements were done at room temperature. A complete thermal characterization of these edible oils was achieved by the relationship between the obtained thermal diffusivities and thermal effusivities with their thermal conductivities and volumetric heat capacities. The obtained results are in agreement with the thermal properties reported for the case of the olive oil.

  4. Modeling of radial asymmetry in lens distortion facilitated by modern optimization techniques

    CSIR Research Space (South Africa)

    De Villiers, Johan P

    2010-01-18

    Full Text Available when applied to low order models. A new tool has been created which can provide extremely accurate distortion characterization. This allows high-end photogrammetric applications to improve their accuracy even if they already use complex models... distortion with a closed form solution and inverse function, Master’s thesis ], University of Pretoria, Pretoria, RSA (2008). [4] Conrady, A., \\Decentered lens systems," Monthly Notices of the Royal Astronomical Society 79, 384{390 (1919). [5] Brown, D...

  5. Combined surgical management of capsular and iris deficiency with glued intraocular lens technique.

    Science.gov (United States)

    Kumar, Dhivya Ashok; Agarwal, Amar; Jacob, Soosan; Lamba, Mandeep; Packialakshmi, Sathiya; Meduri, Alessandro

    2013-05-01

    To determine the outcome after glued aniridia intraocular lens (IOL) and glued IOL with iridoplasty in eyes with combined lens capsular and iris deficiency. Twenty-seven eyes of 25 patients (6 had congenital aniridia with subluxated cataract and 19 had acquired lens/iris defects) were included. Glued IOL with aniridia IOL (Intra Ocular Care, Gujarat, India) was performed in eyes with total aniridia and iridoplasty with glued IOL with a three-piece foldable IOL (Sofport; Bausch & Lomb, Rochester, NY) was performed in eyes with partial aniridia. The postoperative outcomes were analyzed at follow-up examination (range: 6 to 48 months). Eleven eyes underwent glued aniridia IOL and 16 eyes underwent glued IOL with iridoplasty. There was significant improvement in (spectacle) corrected distance visual acuity (CDVA) (P = .002). Postoperatively, pigment dispersion on the IOL (n = 1) and raised intraocular pressure was seen in the glued aniridia IOL group and chronic uveitis (n = 1), cystoid macular edema (n = 1), and hyphema (n = 1) in the glued IOL with iridoplasty group. The CDVA remained unchanged in 14 eyes (51.8%) and improved in 13 eyes (48.1%). There was a difference in postoperative CDVA (P = .001) between eyes with glued aniridia IOL and glued IOL with iridoplasty. There was no IOL decentration, retinal detachment, corneal decompensation, or endophthalmitis. There was reduction in glare and photophobia. Both glued aniridia IOL and glued IOL/iridoplasty showed good functional and anatomical results with fewer complications in eyes with lens capsule and iris deficiency. However, long-term follow-up is required.[J Refract Surg. 2013;29(5):342-347.]. Copyright 2013, SLACK Incorporated.

  6. 3D thermal modelling within the Lofoten-Vesterålen segment of the Mid-Norwegian continental margin

    Science.gov (United States)

    Maystrenko, Yuriy P.; Gernigon, Laurent; Gradmann, Sofie; Olesen, Odleiv

    2017-04-01

    A lithosphere-scale 3D structural model has been constructed based on the available structural data to reveal a deep structure of the Lofoten-Vesterålen segment and the northern part of the Vøring segment of the Mid-Norwegian continental margin. The constructed model covers the Vestfjorden, Ribban and Røst basins, the northern parts of the Vøring Basin and the Trøndelag Platform. The model also extends from the Fennoscandian Shield to the north-eastern part of the North Atlantic Ocean. The initial 3D structural model has been refined using a 3D gravity modelling over the whole study area. The final gravity-consistent model has been used as a structural base for a further 3D thermal modelling, which has been made by use of commercial software package COMSOL Multiphysics. As an upper thermal boundary condition, time-dependent temperature at the Earth's surface and sea bottom has been set, considering palaeoclimatic changes due to the last two Europe-scale glaciations (the Saalian and Weichselian glacial periods). The lithosphere-asthenosphere boundary has been used as a lower thermal boundary which corresponds to the 1300 °C isotherm. In addition to the above-mentioned paleoclimatic scenario, the effects of late Cenozoic erosion onshore and sedimentation offshore have been taken into account during the 3D thermal modelling. Results of this thermal modelling indicate that the continent is generally colder than the basin areas within the upper part of the 3D model. In particular, considering the transient perturbations in the near-surface thermal regime, as a result of the post-Paleogene erosion and sedimentation, helps us to understand additional details of subsurface temperature distribution within the study area. The thermal effects of the simultaneous erosion over the mainland and deposition within the basin areas indicate that a positive thermal anomaly should exist onshore, whereas the negative one must occur in the offshore part. These two thermal

  7. Effect of thermal lens on beam quality and mode matching in LD pumped Er-Yb-codoped phosphate glass microchip laser

    Energy Technology Data Exchange (ETDEWEB)

    Liu Shujing; Song Feng; Cai Hong; Li Teng; Tian Bin; Wu Zhaohui; Tian Jianguo [Photonics Center, Nankai University, Tianjin 300071 (China); Key Laboratory of Advanced Technique and Fabrication for Weak-Light Nonlinear Photonics Materials (Ministry of Education), Nankai University, Tianjin 300457 (China)

    2008-02-07

    The theoretical values of the thermal focal length and laser beam waist are derived from the theoretical model and transformation theory, respectively. The values of thermal focal length, laser beam waist and the far field divergence angle were experimentally measured in a laser diode (LD) pumped erbium-ytterbium(Er-Yb)-codoped phosphate microchip glass laser. As an extension of thermal effect studies, we investigate the role of thermal lens on beam quality and the mode matching between the pump and the laser, which affects laser efficiency in TEM{sub 00} operation. The study shows that the experimental data are in good agreement with the theoretical predictions.

  8. Automated thermal mapping techniques using chromatic image analysis

    Science.gov (United States)

    Buck, Gregory M.

    1989-01-01

    Thermal imaging techniques are introduced using a chromatic image analysis system and temperature sensitive coatings. These techniques are used for thermal mapping and surface heat transfer measurements on aerothermodynamic test models in hypersonic wind tunnels. Measurements are made on complex vehicle configurations in a timely manner and at minimal expense. The image analysis system uses separate wavelength filtered images to analyze surface spectral intensity data. The system was initially developed for quantitative surface temperature mapping using two-color thermographic phosphors but was found useful in interpreting phase change paint and liquid crystal data as well.

  9. A novel technique to monitor thermal discharges using thermal infrared imaging.

    Science.gov (United States)

    Muthulakshmi, A L; Natesan, Usha; Ferrer, Vincent A; Deepthi, K; Venugopalan, V P; Narasimhan, S V

    2013-09-01

    Coastal temperature is an important indicator of water quality, particularly in regions where delicate ecosystems sensitive to water temperature are present. Remote sensing methods are highly reliable for assessing the thermal dispersion. The plume dispersion from the thermal outfall of the nuclear power plant at Kalpakkam, on the southeast coast of India, was investigated from March to December 2011 using thermal infrared images along with field measurements. The absolute temperature as provided by the thermal infrared (TIR) images is used in the Arc GIS environment for generating a spatial pattern of the plume movement. Good correlation of the temperature measured by the TIR camera with the field data (r(2) = 0.89) make it a reliable method for the thermal monitoring of the power plant effluents. The study portrays that the remote sensing technique provides an effective means of monitoring the thermal distribution pattern in coastal waters.

  10. Comparison of Visual Data Collection Techniques on Mizar: The Barlow Lens

    Science.gov (United States)

    Bensel, Holly; Peard, Nolan; Peccia, Dashton; Scimeca, David

    2013-01-01

    Since turning their eyes to the heavens and gazing at the celestial bodies therein, mankind has been restricted and limited in his knowledge of the cosmos by the resolving power of first, the naked-eye, and later, the telescope. It has been the goal of astronomers worldwide to create larger and more powerful telescopes with higher resolving capabilities. Such large telescopes are not an option, however, for amateur astronomers and as such they must rely on other instruments and tools to achieve greater precision. One of these tools is the Barlow lens, used to increase the magnification power of a telescope by increasing its focal length. This magnification can assist in precision and accuracy of observations, especially when measuring the angular separation. Continuing their previous work in double star research (Bensel, Peard, Peccia, Scimeca, et al.), a contingent from St. Mary's School in Medford, Oregon compared the usage of a 2X Barlow lens with their usual telescope configuration and discuss the advantages and disadvantages they experienced with each.

  11. Recent developments in numerical simulation techniques of thermal recovery processes

    Energy Technology Data Exchange (ETDEWEB)

    Tamim, M. [Bangladesh University of Engineering and Technology, Bangladesh (Bangladesh); Abou-Kassem, J.H. [Chemical and Petroleum Engineering Department, UAE University, Al-Ain 17555 (United Arab Emirates); Farouq Ali, S.M. [University of Alberta, Alberta (Canada)

    2000-05-01

    Numerical simulation of thermal processes (steam flooding, steam stimulation, SAGD, in-situ combustion, electrical heating, etc.) is an integral part of a thermal project design. The general tendency in the last 10 years has been to use commercial simulators. During the last decade, only a few new models have been reported in the literature. More work has been done to modify and refine solutions to existing problems to improve the efficiency of simulators. The paper discusses some of the recent developments in simulation techniques of thermal processes such as grid refinement, grid orientation, effect of temperature on relative permeability, mathematical models, and solution methods. The various aspects of simulation discussed here promote better understanding of the problems encountered in the simulation of thermal processes and will be of value to both simulator users and developers.

  12. Argonne National Laboratory's thermal plume measurements: instruments and techniques

    International Nuclear Information System (INIS)

    Van Loon, L.S.; Frigo, A.A.; Paddock, R.A.

    1977-12-01

    Instrumentation and techniques were developed at Argonne National Laboratory for measuring the three-dimensional temperature structure of thermal plumes from power plants, along with the limnological, meteorological, and plant operating conditions affecting their behavior. The equipment and procedures were designed to provide field data for use in evaluating predictive models that describe thermal plume behavior, and over 100 sets of these data have been collected. The instrument systems and techniques employed in a typical thermal discharge survey are highly integrated. Continuous monitoring of ambient and plant conditions is coupled with plume mapping from a moving survey boat. The instantaneous location of the boat together with subsurface temperature measurements from a towed thermistor chain provide a quasisynoptic view of the plume structure. Real-time, onboard display of the boat path and vertical temperatures supply feedback to investigators for determining the extent and spatial resolution of measurements required. The unique design, reliability, accuracy, calibration, and historical development of the components of these integrated systems are described. Survey system interfaces with data handling and processing techniques are also explained. Special supportive studies to investigate plume dynamics, values of eddy diffusivities, time-temperature histories of water parcels in thermal plumes, and rapid changes in plume shape are also described along with instrumentation used

  13. Supracapsular glued intraocular lens in progressive subluxated cataracts: Technique to retain an intact vitreous face.

    Science.gov (United States)

    Jacob, Soosan; Narasimhan, Smita; Agarwal, Amar; Mazzotta, Cosimo; Rechichi, Miguel; Agarwal, Athiya

    2017-03-01

    We describe a technique to prevent late intraocular lens (IOL) subluxation and dislocation that can be associated with progressive zonulopathy. Supracapsular glued IOL fixation is done to retain an intact anterior hyaloid face and avoid vitreous disturbance while providing stable long-term IOL fixation. Phacoemulsification is followed by glued IOL implantation above intact anterior and posterior capsules. Sclerotomies are created ab interno in a supracapsular plane under diametrically opposite lamellar scleral flaps without entering the vitreous cavity. Haptics are externalized in the supracapsular plane and tucked into intrascleral tunnels. Intraoperative or postoperative posterior capsulorhexis or capsulotomy and anterior capsule relaxing cuts can prevent capsule phimosis. Copyright © 2017 ASCRS and ESCRS. Published by Elsevier Inc. All rights reserved.

  14. Electropyroelectric technique for measurement of the thermal effusivity of liquids

    Energy Technology Data Exchange (ETDEWEB)

    Ivanov, R; Moreno, I; Araujo, C [Facultad de Fisica, Universidad Autonoma de Zacatecas, Calz. Solidaridad Esquina Paseo de la Bufa s/n, C. P. 98060, Zacatecas, Zac. (Mexico); Marin, E, E-mail: emarin63@yahoo.e, E-mail: emarinm@ipn.m [Centro de Investigacion en Ciencia Aplicada y TecnologIa Avanzada, Instituto Politecnico Nacional, LegarIa 694, Colonia Irrigacion, C. P. 11500, Mexico D. F. (Mexico)

    2010-06-09

    The photopyroelectric method has been recognized as a reliable and useful tool for the measurement of the thermal properties of condensed matter samples. Usually the photothermal signal is generated using intensity modulated light beams, whose amplitudes are difficult to maintain stable. In this paper we describe a variant of this technique that uses amplitude modulated electrical current as excitation source, via Joule heating of the metal contact on one side of the pyroelectric sensor. The possibilities of this method, called by us the electropyroelectric technique, for thermal effusivity measurements of liquid samples are shown using test samples of distilled water, ethanol and glycerine. The results obtained for this parameter agree well with the values reported in the literature. Our measurement uncertainties are about 3%, a fact that opens several possible applications.

  15. Electropyroelectric technique for measurement of the thermal effusivity of liquids

    International Nuclear Information System (INIS)

    Ivanov, R; Moreno, I; Araujo, C; Marin, E

    2010-01-01

    The photopyroelectric method has been recognized as a reliable and useful tool for the measurement of the thermal properties of condensed matter samples. Usually the photothermal signal is generated using intensity modulated light beams, whose amplitudes are difficult to maintain stable. In this paper we describe a variant of this technique that uses amplitude modulated electrical current as excitation source, via Joule heating of the metal contact on one side of the pyroelectric sensor. The possibilities of this method, called by us the electropyroelectric technique, for thermal effusivity measurements of liquid samples are shown using test samples of distilled water, ethanol and glycerine. The results obtained for this parameter agree well with the values reported in the literature. Our measurement uncertainties are about 3%, a fact that opens several possible applications.

  16. Measurements of He II Thermal Counterflow Using PIV Technique

    International Nuclear Information System (INIS)

    Zhang, T.; Van Sciver, S.W.

    2004-01-01

    Our previous experiments on the measurements of He II thermal counterflow using Particle Image Velocimetry (PIV) have shown that there exists a substantial discrepancy between the measured and theoretical values of normal fluid velocity. It was assumed that this is due to the slip velocity between tracer particles and liquid helium. In the present work, tracer particles with a much smaller mean diameter and a more uniform size distribution were selected in order to reduce the effect of slip velocity, and an improved two phase fluidized bed technique was used to introduce the particles into liquid helium. The normal fluid velocity of thermal counterflow was then measured using the PIV technique at various heat fluxes and bath temperatures. The experimental results, however, still show the existence of discrepancy between PIV measured particle velocities and the theoretical normal fluid velocity. A preliminary explanation of these results is given based on an interaction of tracer particles with the superfluid component in the He II

  17. TIGER: Development of Thermal Gradient Compensation Algorithms and Techniques

    Science.gov (United States)

    Hereford, James; Parker, Peter A.; Rhew, Ray D.

    2004-01-01

    In a wind tunnel facility, the direct measurement of forces and moments induced on the model are performed by a force measurement balance. The measurement balance is a precision-machined device that has strain gages at strategic locations to measure the strain (i.e., deformations) due to applied forces and moments. The strain gages convert the strain (and hence the applied force) to an electrical voltage that is measured by external instruments. To address the problem of thermal gradients on the force measurement balance NASA-LaRC has initiated a research program called TIGER - Thermally-Induced Gradients Effects Research. The ultimate goals of the TIGER program are to: (a) understand the physics of the thermally-induced strain and its subsequent impact on load measurements and (b) develop a robust thermal gradient compensation technique. This paper will discuss the impact of thermal gradients on force measurement balances, specific aspects of the TIGER program (the design of a special-purpose balance, data acquisition and data analysis challenges), and give an overall summary.

  18. High power single-frequency and frequency-doubled laser with active compensation for the thermal lens effect of terbium gallium garnet crystal.

    Science.gov (United States)

    Yin, Qiwei; Lu, Huadong; Su, Jing; Peng, Kunchi

    2016-05-01

    The thermal lens effect of terbium gallium garnet (TGG) crystal in a high power single-frequency laser severely limits the output power and the beam quality of the laser. By inserting a potassium dideuterium phosphate (DKDP) slice with negative thermo-optical coefficient into the laser resonator, the harmful influence of the thermal lens effect of the TGG crystal can be effectively mitigated. Using this method, the stable range of the laser is broadened, the bistability phenomenon of the laser during the process of changing the pump power is completely eliminated, the highest output power of an all-solid-state continuous-wave intracavity-frequency-doubling single-frequency laser at 532 nm is enhanced to 30.2 W, and the beam quality of the laser is significantly improved.

  19. Wood lens design philosophy based on a binary additive manufacturing technique

    Science.gov (United States)

    Marasco, Peter L.; Bailey, Christopher

    2016-04-01

    Using additive manufacturing techniques in optical engineering to construct a gradient index (GRIN) optic may overcome a number of limitations of GRIN technology. Such techniques are maturing quickly, yielding additional design degrees of freedom for the engineer. How best to employ these degrees of freedom is not completely clear at this time. This paper describes a preliminary design philosophy, including assumptions, pertaining to a particular printing technique for GRIN optics. It includes an analysis based on simulation and initial component measurement.

  20. Use of advanced modeling techniques to optimize thermal packaging designs.

    Science.gov (United States)

    Formato, Richard M; Potami, Raffaele; Ahmed, Iftekhar

    2010-01-01

    Through a detailed case study the authors demonstrate, for the first time, the capability of using advanced modeling techniques to correctly simulate the transient temperature response of a convective flow-based thermal shipper design. The objective of this case study was to demonstrate that simulation could be utilized to design a 2-inch-wall polyurethane (PUR) shipper to hold its product box temperature between 2 and 8 °C over the prescribed 96-h summer profile (product box is the portion of the shipper that is occupied by the payload). Results obtained from numerical simulation are in excellent agreement with empirical chamber data (within ±1 °C at all times), and geometrical locations of simulation maximum and minimum temperature match well with the corresponding chamber temperature measurements. Furthermore, a control simulation test case was run (results taken from identical product box locations) to compare the coupled conduction-convection model with a conduction-only model, which to date has been the state-of-the-art method. For the conduction-only simulation, all fluid elements were replaced with "solid" elements of identical size and assigned thermal properties of air. While results from the coupled thermal/fluid model closely correlated with the empirical data (±1 °C), the conduction-only model was unable to correctly capture the payload temperature trends, showing a sizeable error compared to empirical values (ΔT > 6 °C). A modeling technique capable of correctly capturing the thermal behavior of passively refrigerated shippers can be used to quickly evaluate and optimize new packaging designs. Such a capability provides a means to reduce the cost and required design time of shippers while simultaneously improving their performance. Another advantage comes from using thermal modeling (assuming a validated model is available) to predict the temperature distribution in a shipper that is exposed to ambient temperatures which were not bracketed

  1. Using geophysical techniques to control in situ thermal remediation

    International Nuclear Information System (INIS)

    Boyd, S.; Daily, W.; Ramirez, A.; Wilt, M.; Goldman, R.; Kayes, D.; Kenneally, K.; Udell, K.; Hunter, R.

    1994-01-01

    Monitoring the thermal and hydrologic processes that occur during thermal environmental remediation programs in near real-time provides essential information for controlling the process. Geophysical techniques played a crucial role in process control as well as for characterization during the recent Dynamic Underground Stripping Project demonstration in which several thousand gallons of gasoline were removed from heterogeneous soils both above and below the water table. Dynamic Underground Stripping combines steam injection and electrical heating for thermal enhancement with ground water pumping and vacuum extraction for contaminant removal. These processes produce rapid changes in the subsurface properties including changes in temperature fluid saturation, pressure and chemistry. Subsurface imaging methods are used to map the heated zones and control the thermal process. Temperature measurements made in wells throughout the field reveal details of the complex heating phenomena. Electrical resistance tomography (ERT) provides near real-time detailed images of the heated zones between boreholes both during electrical heating and steam injection. Borehole induction logs show close correlation with lithostratigraphy and, by identifying the more permeable gravel zones, can be used to predict steam movement. They are also useful in understanding the physical changes in the field and in interpreting the ERT images. Tiltmeters provide additional information regarding the shape of the steamed zones in plan view. They were used to track the growth of the steam front from individual injectors

  2. Synchrotron X-ray measurement techniques for thermal barrier coated cylindrical samples under thermal gradients

    Energy Technology Data Exchange (ETDEWEB)

    Siddiqui, Sanna F.; Knipe, Kevin; Manero, Albert; Raghavan, Seetha [Department of Mechanical and Aerospace Engineering, University of Central Florida, Orlando, Florida 32816 (United States); Meid, Carla; Wischek, Janine; Bartsch, Marion [German Aerospace Center (DLR), Institute of Materials Research, 51147 Cologne (Germany); Okasinski, John; Almer, Jonathan [X-Ray Science Division, Advanced Photon Source, Argonne National Laboratory, Argonne, Illinois 60439 (United States); Karlsson, Anette M. [Cleveland State University, 2121 Euclid Avenue, Cleveland, Ohio 44115 (United States)

    2013-08-15

    Measurement techniques to obtain accurate in situ synchrotron strain measurements of thermal barrier coating systems (TBCs) applied to hollow cylindrical specimens are presented in this work. The Electron Beam Physical Vapor Deposition coated specimens with internal cooling were designed to achieve realistic temperature gradients over the TBC coated material such as that occurring in the turbine blades of aeroengines. Effects of the circular cross section on the x-ray diffraction (XRD) measurements in the various layers, including the thermally grown oxide, are investigated using high-energy synchrotron x-rays. Multiple approaches for beam penetration including collection, tangential, and normal to the layers, along with variations in collection parameters are compared for their ability to attain high-resolution XRD data from the internal layers. This study displays the ability to monitor in situ, the response of the internal layers within the TBC, while implementing a thermal gradient across the thickness of the coated sample. The thermal setup maintained coating surface temperatures in the range of operating conditions, while monitoring the substrate cooling, for a controlled thermal gradient. Through variation in measurement location and beam parameters, sufficient intensities are obtained from the internal layers which can be used for depth resolved strain measurements. Results are used to establish the various techniques for obtaining XRD measurements through multi-layered coating systems and their outcomes will pave the way towards goals in achieving realistic in situ testing of these coatings.

  3. 3-D thermal effect of late Cenozoic erosion and deposition within the Lofoten-Vesterålen segment of the Mid-Norwegian continental margin

    Science.gov (United States)

    Maystrenko, Yuriy Petrovich; Gernigon, Laurent; Olesen, Odleiv; Ottesen, Dag; Rise, Leif

    2018-05-01

    A 3-D subsurface temperature distribution within the Lofoten-Vesterålen segment of the Mid-Norwegian continental margin and adjacent areas has been studied to understand the thermal effect of late Cenozoic erosion of old sedimentary and crystalline rocks and subsequent deposition of glacial sediments during the Pleistocene. A lithosphere-scale 3-D structural model of the Lofoten-Vesterålen area has been used as a realistic approximation of the geometries of the sedimentary infill, underlying crystalline crust and lithospheric mantle during the 3-D thermal modelling. The influence of late Cenozoic erosion and sedimentation has been included during the 3-D thermal calculations. In addition, the 3-D thermal modelling has been carried out by taking also into account the influence of early Cenozoic continental breakup. The results of the 3-D thermal modelling demonstrate that the mainland is generally colder than the basin areas within the upper part of the 3-D model. The thermal influence of the early Cenozoic breakup is still clearly recognizable within the western and deep parts of the Lofoten-Vesterålen margin segment in terms of the increased temperatures. The thermal effects of the erosion and deposition within the study area also indicate that a positive thermal anomaly exists within the specific subareas where sedimentary and crystalline rocks were eroded. A negative thermal effect occurs in the subareas affected by subsidence and sedimentation. The erosion-related positive thermal anomaly reaches its maximum of more than +27 °C at depths of 17-22 km beneath the eastern part of the Vestfjorden Basin. The most pronounced deposition-related negative anomaly shows a minimum of around -70 °C at 17-20 km depth beneath the Lofoten Basin. The second negative anomaly is located within the northeastern part of the Vøring Basin and has minimal values of around -48 °C at 12-14 km depth. These prominent thermal anomalies are associated with the subareas where

  4. Carbon filter property detection with thermal neutron technique

    International Nuclear Information System (INIS)

    Deng Zhongbo; Han Jun; Li Wenjie

    2003-01-01

    The paper discussed the mechanism that the antigas property of the carbon filter will decrease because of its carbon bed absorbing water from the air while the carbon filter is being stored, and introduced the principle and method of detection the amount of water absorption with thermal neutron technique. Because some certain relation between the antigas property of the carbon filter and the amount of water absorption exists, the decrease degree of the carbon filter antigas property can be estimated through the amount of water absorption, offering a practicable facility technical pathway to quickly non-destructively detect the carbon filter antigas property

  5. Thermal mapping of mountain slopes on Mars by application of a Differential Apparent Thermal Inertia technique

    Science.gov (United States)

    Kubiak, Marta; Mège, Daniel; Gurgurewicz, Joanna; Ciazela, Jakub

    2015-04-01

    Thermal inertia (P) is an important property of geologic surfaces that essentially describes the resistance to temperature (T) change as heat is added. Most remote sensing data describe the surface only. P is a volume property that is sensitive to the composition of the subsurface, down to a depth reached by the diurnal heating wave. As direct measurement of P is not possible on Mars, thermal inertia models (Fergason et al., 2006) and deductive methods (the Apparent Thermal Inertia: ATI and Differential Apparent Thermal Inertia: DATI) are used to estimate it. ATI is computed as (1 - A) / (Tday - Tnight), where A is albedo. Due to the lack of the thermal daytime images with maximum land surface temperature (LST) and nighttime images with minimum LST in Valles Marineris region, the ATI method is difficult to apply. Instead, we have explored the DATI technique (Sabol et al., 2006). DATI is calculated based on shorter time (t) intervals with a high |ΔT/Δt| gradient (in the morning or in the afternoon) and is proportional to the day/night temperature difference (ATI), and hence P. Mars, which exhibits exceptionally high |ΔT/Δt| gradients due to the lack of vegetation and thin atmosphere, is especially suitable for the DATI approach. Here we present a new deductive method for high-resolution differential apparent thermal inertia (DATI) mapping for areas of highly contrasted relief (e.g., Valles Marineris). Contrary to the thermal inertia models, our method takes local relief characteristics (slopes and aspects) into account. This is crucial as topography highly influences A and ΔT measurements. In spite of the different approach, DATI values in the flat areas are in the same range as the values obtained by Fergason et al. (2006). They provide, however, more accurate information for geological interpretations of hilly or mountainous terrains. Sabol, D. E., Gillespie, A. R., McDonald, E., and Danilina, I., 2006. Differential Thermal Inertia of Geological Surfaces. In

  6. 3-D thermal weight function method and multiple virtual crack extension technique for thermal shock problems

    International Nuclear Information System (INIS)

    Lu Yanlin; Zhou Xiao; Qu Jiadi; Dou Yikang; He Yinbiao

    2005-01-01

    An efficient scheme, 3-D thermal weight function (TWF) method, and a novel numerical technique, multiple virtual crack extension (MVCE) technique, were developed for determination of histories of transient stress intensity factor (SIF) distributions along 3-D crack fronts of a body subjected to thermal shock. The TWF is a universal function, which is dependent only on the crack configuration and body geometry. TWF is independent of time during thermal shock, so the whole history of transient SIF distributions along crack fronts can be directly calculated through integration of the products of TWF and transient temperatures and temperature gradients. The repeated determinations of the distributions of stresses (or displacements) fields for individual time instants are thus avoided in the TWF method. An expression of the basic equation for the 3-D universal weight function method for Mode I in an isotropic elastic body is derived. This equation can also be derived from Bueckner-Rice's 3-D WF formulations in the framework of transformation strain. It can be understood from this equation that the so-called thermal WF is in fact coincident with the mechanical WF except for some constants of elasticity. The details and formulations of the MVCE technique are given for elliptical cracks. The MVCE technique possesses several advantages. The specially selected linearly independent VCE modes can directly be used as shape functions for the interpolation of unknown SIFs. As a result, the coefficient matrix of the final system of equations in the MVCE method is a triple-diagonal matrix and the values of the coefficients on the main diagonal are large. The system of equations has good numerical properties. The number of linearly independent VCE modes that can be introduced in a problem is unlimited. Complex situations in which the SIFs vary dramatically along crack fronts can be numerically well simulated by the MVCE technique. An integrated system of programs for solving the

  7. A classification system of intraocular lens dislocation sites under operating microscopy, and the surgical techniques and outcomes of exchange surgery.

    Science.gov (United States)

    Hayashi, Ken; Ogawa, Soichiro; Manabe, Shin-Ichi; Hirata, Akira; Yoshimura, Koichi

    2016-03-01

    The aim of this study was to examine the recent status of intraocular lens (IOL) dislocation according to a classification system based on vertical dislocation position, as well as the surgical techniques and outcomes of IOL exchange surgery. The medical records of 230 eyes from 214 consecutive patients who experienced IOL dislocation and underwent exchange surgery between 2006 and 2014 were reviewed. Vertical dislocation sites observed preoperatively under operating microscopy were examined, along with the surgical techniques and outcomes of IOL exchange. Dislocation sites included (1) the anterior chamber (12.2 %), (2) pseudophakodonesis (19.1 %), (3) the anterior vitreous cavity (47.4 %), (4) trap door-like dislocation (dangling in the peripheral vitreous cavity; 16.1 %), and (5) the retinal surface (5.2 %). The IOL retained in the anterior segment was moved onto the iris by pulling it up through the limbal side ports with an anterior vitrectomy (67.8 %), or by pushing it up from the pars plana with an anterior vitrectomy (26.5 %), while the IOL dropped on the retina was lifting it up from the retina after pars plana vitrectomy (5.7 %). Mean uncorrected and distance-corrected visual acuity significantly improved postoperatively (p system, approximately 95 % of dislocated IOLs were retained in the anterior segment, and these IOLs were exchanged using an anterior approach through limbal incisions with an anterior vitrectomy. Visual acuity improved significantly, and serious complications were uncommon, probably because the IOL exchange techniques were standardized and simplified without pars plana vitrectomy.

  8. Luneburg lens in silicon photonics.

    Science.gov (United States)

    Di Falco, Andrea; Kehr, Susanne C; Leonhardt, Ulf

    2011-03-14

    The Luneburg lens is an aberration-free lens that focuses light from all directions equally well. We fabricated and tested a Luneburg lens in silicon photonics. Such fully-integrated lenses may become the building blocks of compact Fourier optics on chips. Furthermore, our fabrication technique is sufficiently versatile for making perfect imaging devices on silicon platforms.

  9. Atomic force microscopy and Langmuir–Blodgett monolayer technique to assess contact lens deposits and human meibum extracts

    Directory of Open Access Journals (Sweden)

    Sarah Hagedorn

    2015-07-01

    Conclusions: MGD and non-MGD participant-worn CL deposition were found to differ in type, amount, and pattern of lens deposits. Lipids from MGD participants deposited irregularly whereas lipids from non-MGD participants showed more uniformity.

  10. Minimizing and measuring lens dose when giving cranial irradiation

    International Nuclear Information System (INIS)

    Woo, S.Y.; Donaldson, S.S.; Heck, R.J.; Nielson, K.L.; Shostak, C.

    1989-01-01

    Three different techniques of administering cranial irradiation were used to determine the dose to the lens as measured in the Rando phantom. The techniques employed were as follows: (1) the central axis of the radiation beam was placed at the thickest portion of the cranium; (2) the central axis of the radiation beam was placed at the lateral orbital rim (bon canthus); (3) the central axis of the radiation beam was placed at the thickest portion of the cranium but with the beam angled 5deg posteriorly away from the eye. Thermal luminescent dosimeters (TLD) were placed in a phantom, at a point determined from a life-sized anatomical section of the plane through the midsection of the eye, to be at the location of the posterior capsule of the lens. In addition, TLDs were placed on the outer surface of the phantom head, directly lateral to the location determined to be where the lens would lie. With equally weighted lateral opposed beams, delivering a midplane dose of 200cGy, the TLDs at the point of the lens measured 21, 9.9 and 10.6% of the midplane doses from the three techniques respectively. TLDs placed directly lateral to the lens on the surface of the phantom head gave an approximation of the lens dose, particularly when techniques 2 and 3 were used. Isodose curve generated by a General Electric treatment planning computer gave lens doses similar to those of the phantom data for each of the three different radiotherapy techniques. Cranial irradiation should be carried out by either technique 2 or technique 3 to minimize radiation dose to the lens. (author). 11 refs.; 2 figs.; 3 tabs

  11. Waste cell phone recycling by thermal plasma techniques

    Energy Technology Data Exchange (ETDEWEB)

    Inaba, T.; Kunimoto, N.; Abe, S. [Chuo Univ., Bunkyo-Ku, Tokyo (Japan). Dept. of Electrical, Electronics, and Communication Engineering; Li, O.L.; Chang, J.S.; Ruj, B. [McMaster Univ., Hamilton, ON (Canada). Faculty of Engineering

    2010-07-01

    Due to the cost-effective nature of wireless networks, the number of cell phones used around the world has increased significantly. However, a major problem of this technology is the generation of a great deal of complex electronics wastes, such as cell phones. The typical average life of a cell phone is around 2 years. Therefore, inexpensive recycling techniques must be developed for valuable resources such as real metals and plastics used in cell phones. Thermal plasma has been used for many different waste treatments since it has the capability to detoxify waste by-products. This paper presented a preliminary investigation for cell phone recycling by a thermal plasma technology. Recyclable resource material was identified by neutron activation analyses. Then, the cell phone waste was first crashed and treated by Ar twin torch plasmas to remove the majority of organic materials. The paper described the experimental apparatus and results. It was concluded that styrene (C{sub 8}H{sub 8}) and benzene (C{sub 6}H{sub 6}O) may be two major by-products in on-line by-products gas. The molecule becomes a much heavier by-product gas after cooling down. 6 refs., 6 figs.

  12. A Thermal Technique of Fault Nucleation, Growth, and Slip

    Science.gov (United States)

    Garagash, D.; Germanovich, L. N.; Murdoch, L. C.; Martel, S. J.; Reches, Z.; Elsworth, D.; Onstott, T. C.

    2009-12-01

    Fractures and fluids influence virtually all mechanical processes in the crust, but many aspects of these processes remain poorly understood largely because of a lack of controlled field experiments at appropriate scale. We have developed an in-situ experimental approach to create carefully controlled faults at scale of ~10 meters using thermal techniques to modify in situ stresses to the point where the rock fails in shear. This approach extends experiments on fault nucleation and growth to length scales 2-3 orders of magnitude greater than are currently possible in the laboratory. The experiments could be done at depths where the modified in situ stresses are sufficient to drive faulting, obviating the need for unrealistically large loading frames. Such experiments require an access to large rock volumes in the deep subsurface in a controlled setting. The Deep Underground Science and Engineering Laboratory (DUSEL), which is a research facility planned to occupy the workings of the former Homestake gold mine in the northern Black Hills, South Dakota, presents an opportunity for accessing locations with vertical stresses as large as 60 MPa (down to 2400 m depth), which is sufficient to create faults. One of the most promising methods for manipulating stresses to create faults that we have evaluated involves drilling two parallel planar arrays of boreholes and circulating cold fluid (e.g., liquid nitrogen) to chill the region in the vicinity of the boreholes. Cooling a relatively small region around each borehole causes the rock to contract, reducing the normal compressive stress throughout much larger region between the arrays of boreholes. This scheme was evaluated using both scaling analysis and a finite element code. Our results show that if the boreholes are spaced by ~1 m, in several days to weeks, the normal compressive stress can be reduced by 10 MPa or more, and it is even possible to create net tension between the borehole arrays. According to the Mohr

  13. Orbital maneuvering vehicle thermal design and analysis techniques

    Science.gov (United States)

    Chapter, J.

    1986-01-01

    This paper describes the OMV thermal design that is required to maintain components within temperature limits for all mission phases. A key element in the OMV thermal design is the application of a motorized thermal shade assembly that is a replacement for the more conventional variable conductance heat pipes or louvers. The thermal shade assembly covers equipment module radiator areas, and based upon the radiator temperature input to onboard computer, opens and closes the shade, varying the effective radiator area. Thermal design verification thermal analyses results are presented. Selected thermal analyses methods, including several unique subroutines, are discussed. A representation of enclosure Script F equations, in matrix form, is also included. Personal computer application to the development of the OMV thermal design is summarized.

  14. Thermal Conductivity of EB-PVD Thermal Barrier Coatings Evaluated by a Steady-State Laser Heat Flux Technique

    Science.gov (United States)

    Zhu, Dongming; Miller, Robert A.; Nagaraj, Ben A.; Bruce, Robert W.

    2000-01-01

    The thermal conductivity of electron beam-physical vapor deposited (EB-PVD) Zr02-8wt%Y2O3 thermal barrier coatings was determined by a steady-state heat flux laser technique. Thermal conductivity change kinetics of the EB-PVD ceramic coatings were also obtained in real time, at high temperatures, under the laser high heat flux, long term test conditions. The thermal conductivity increase due to micro-pore sintering and the decrease due to coating micro-delaminations in the EB-PVD coatings were evaluated for grooved and non-grooved EB-PVD coating systems under isothermal and thermal cycling conditions. The coating failure modes under the high heat flux test conditions were also investigated. The test technique provides a viable means for obtaining coating thermal conductivity data for use in design, development, and life prediction for engine applications.

  15. Iron oxide functionalized graphene oxide as an efficient sorbent for dispersive micro-solid phase extraction of sulfadiazine followed by spectrophotometric and mode-mismatched thermal lens spectrometric determination.

    Science.gov (United States)

    Kazemi, Elahe; Dadfarnia, Shayessteh; Haji Shabani, Ali Mohammad; Abbasi, Amir; Rashidian Vaziri, Mohammad Reza; Behjat, Abbas

    2016-01-15

    A simple and rapid dispersive micro-solid phase extraction (DMSPE) combined with mode-mismatched thermal lens spectrometry as well as fiber optic linear array spectrophotometry was developed for the separation, extraction and determination of sulfadiazine. Graphene oxide was synthesized using the modified Hummers method and functionalized with iron oxide nanoparticles by means of a simple one step chemical coprecipitation method. The synthesized iron oxide functionalized graphene oxide was utilized as an efficient sorbent in DMSPE of sulfadiazine. The retained analyte was eluted by using 180µL of a 6:4 mixture of methanol/acetic acid solution and was spectrophotometrically determined based on the formation of an azo dye through coupling with thenoyltrifluoroacetone. Under the optimized conditions, with the application of spectrophotometry technique and with a sample volume of 100mL, the method exhibited a linear dynamic range of 3-80µg L(-1) with a detection limit of 0.82µg L(-1), an enrichment factor of 200 as well as the relative standard deviations of 2.6% and 4.3% (n=6) at 150µg L(-1) level of sulfadiazine for intra- and inter-day analyses, respectively. Whereas, through the application of the thermal lens spectrometry and a sample volume of 10mL, the method exhibited a linear dynamic range of 1-800µg L(-1) with a detection limit of 0.34µg L(-1) and the relative standard deviations of 3.1% and 5.4% (n=6) at 150µg L(-1) level of sulfadiazine for intra- and inter-day analyses, respectively. The method was successfully applied to the determination of sulfadiazine in milk, honey and water samples. Copyright © 2015 Elsevier B.V. All rights reserved.

  16. The Measurement of Thermal Diffusivity in Conductor and Insulator by Photodeflection Technique

    Science.gov (United States)

    Achathongsuk, U.; Rittidach, T.; Tipmonta, P.; Kijamnajsuk, P.; Chotikaprakhan, S.

    2017-09-01

    The purpose of this study is to estimate thermal diffusivities of high thermal diffusivity bulk material as well as low thermal diffusivity bulk material by using many types of fluid such as Ethyl alcohol and water. This method is studied by measuring amplitude and phase of photodeflection signal in various frequency modulations. The experimental setup consists of two laser lines: 1) a pump laser beams through a modulator, varied frequency, controlled by lock-in amplifier and focused on sample surface by lens. 2) a probe laser which parallels with the sample surface and is perpendicular to the pump laser beam. The probe laser deflection signal is obtained by a position sensor which controlled by lock-in amplifier. Thermal diffusivity is calculated by measuring the amplitude and phase of the photodeflection signal and compared with the thermal diffusivity of a standard value. The thermal diffusivity of SGG agrees well with the literature but the thermal diffusivity of Cu is less than the literature value by a factor of ten. The experiment requires further improvement to measure the thermal diffusivity of Cu. However, we succeed in using ethyl alcohol as the coupling medium instead of CCl4 which is highly toxic.

  17. Local thermal conductivity of polycrystalline AlN ceramics measured by scanning thermal microscopy and complementary scanning electron microscopy techniques

    International Nuclear Information System (INIS)

    Zhang Yue-Fei; Wang Li; Wei Bin; Ji Yuan; Han Xiao-Dong; Zhang Ze; Heiderhoff, R.; Geinzer, A. K.; Balk, L. J.

    2012-01-01

    The local thermal conductivity of polycrystalline aluminum nitride (AlN) ceramics is measured and imaged by using a scanning thermal microscope (SThM) and complementary scanning electron microscope (SEM) based techniques at room temperature. The quantitative thermal conductivity for the AlN sample is gained by using a SThM with a spatial resolution of sub-micrometer scale through using the 3ω method. A thermal conductivity of 308 W/m·K within grains corresponding to that of high-purity single crystal AlN is obtained. The slight differences in thermal conduction between the adjacent grains are found to result from crystallographic misorientations, as demonstrated in the electron backscattered diffraction. A much lower thermal conductivity at the grain boundary is due to impurities and defects enriched in these sites, as indicated by energy dispersive X-ray spectroscopy. (condensed matter: structural, mechanical, and thermal properties)

  18. Application of Advanced Particle Swarm Optimization Techniques to Wind-thermal Coordination

    DEFF Research Database (Denmark)

    Singh, Sri Niwas; Østergaard, Jacob; Yadagiri, J.

    2009-01-01

    wind-thermal coordination algorithm is necessary to determine the optimal proportion of wind and thermal generator capacity that can be integrated into the system. In this paper, four versions of Particle Swarm Optimization (PSO) techniques are proposed for solving wind-thermal coordination problem...

  19. Atomic force microscopy and Langmuir-Blodgett monolayer technique to assess contact lens deposits and human meibum extracts.

    Science.gov (United States)

    Hagedorn, Sarah; Drolle, Elizabeth; Lorentz, Holly; Srinivasan, Sruthi; Leonenko, Zoya; Jones, Lyndon

    2015-01-01

    The purpose of this exploratory study was to investigate the differences in meibomian gland secretions, contact lens (CL) lipid extracts, and CL surface topography between participants with and without meibomian gland dysfunction (MGD). Meibum study: Meibum was collected from all participants and studied via Langmuir-Blodgett (LB) deposition with subsequent Atomic Force Microscopy (AFM) visualization and surface roughness analysis. CL Study: Participants with and without MGD wore both etafilcon A and balafilcon A CLs in two different phases. CL lipid deposits were extracted and analyzed using pressure-area isotherms with the LB trough and CL surface topographies and roughness values were visualized using AFM. Meibum study: Non-MGD participant meibum samples showed larger, circular aggregates with lower surface roughness, whereas meibum samples from participants with MGD showed more lipid aggregates, greater size variability and higher surface roughness. CL Study: Worn CLs from participants with MGD had a few large tear film deposits with lower surface roughness, whereas non-MGD participant-worn lenses had many small lens deposits with higher surface roughness. Balafilcon A pore depths were shallower in MGD participant worn lenses when compared to non-MGD participant lenses. Isotherms of CL lipid extracts from MGD and non-MGD participants showed a seamless rise in surface pressure as area decreased; however, extracts from the two different lens materials produced different isotherms. MGD and non-MGD participant-worn CL deposition were found to differ in type, amount, and pattern of lens deposits. Lipids from MGD participants deposited irregularly whereas lipids from non-MGD participants showed more uniformity. Copyright © 2014 Spanish General Council of Optometry. Published by Elsevier Espana. All rights reserved.

  20. [Capsule contraction as a cause of in-the-bag intraocular lens subluxation and simplified technique of IOL reposition].

    Science.gov (United States)

    Jurowski, Piotr

    2005-01-01

    Presentation of the case of the pseudophakic patient in whom 3 months after uncomplicated phacoemulsification severe capsule contraction syndrome, followed by equatorial capsule fibrosis, 240 degree zonular dialysis, and spontaneous in-the-bag intraocular lens subluxation, were observed. Consecutive surgical intervention consisting of simplified transscleral "free haptic" through the capsule fixation and additional plastic of phimotic capsulorrhexis allowed to restore the best corrected visual acuity to 20/25.

  1. Objective lens

    Science.gov (United States)

    Olczak, Eugene G. (Inventor)

    2011-01-01

    An objective lens and a method for using same. The objective lens has a first end, a second end, and a plurality of optical elements. The optical elements are positioned between the first end and the second end and are at least substantially symmetric about a plane centered between the first end and the second end.

  2. [Research progress and development trend of quantitative assessment techniques for urban thermal environment.

    Science.gov (United States)

    Sun, Tie Gang; Xiao, Rong Bo; Cai, Yun Nan; Wang, Yao Wu; Wu, Chang Guang

    2016-08-01

    Quantitative assessment of urban thermal environment has become a focus for urban climate and environmental science since the concept of urban heat island has been proposed. With the continual development of space information and computer simulation technology, substantial progresses have been made on quantitative assessment techniques and methods of urban thermal environment. The quantitative assessment techniques have been developed to dynamics simulation and forecast of thermal environment at various scales based on statistical analysis of thermal environment on urban-scale using the historical data of weather stations. This study reviewed the development progress of ground meteorological observation, thermal infrared remote sensing and numerical simulation. Moreover, the potential advantages and disadvantages, applicability and the development trends of these techniques were also summarized, aiming to add fundamental knowledge of understanding the urban thermal environment assessment and optimization.

  3. Techniques for the thermal/hydraulic analysis of LMFBR check valves

    International Nuclear Information System (INIS)

    Cho, S.M.; Kane, R.S.

    1979-01-01

    A thermal/hydraulic analysis of the check valves in liquid sodium service for LMFBR plants is required to provide temperature data for thermal stress analysis of the valves for specified transient conditions. Because of the complex three-dimensional flow pattern within the valve, the heat transfer analysis techniques for less complicated shapes could not be used. This paper discusses the thermal analysis techniques used to assure that the valve stress analysis is conservative. These techniques include a method for evaluating the recirculating flow patterns and for selecting appropriately conservative heat transfer correlations in various regions of the valve

  4. Standard Test Method for Determining Thermal Neutron Reaction Rates and Thermal Neutron Fluence Rates by Radioactivation Techniques

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2008-01-01

    1.1 The purpose of this test method is to define a general procedure for determining an unknown thermal-neutron fluence rate by neutron activation techniques. It is not practicable to describe completely a technique applicable to the large number of experimental situations that require the measurement of a thermal-neutron fluence rate. Therefore, this method is presented so that the user may adapt to his particular situation the fundamental procedures of the following techniques. 1.1.1 Radiometric counting technique using pure cobalt, pure gold, pure indium, cobalt-aluminum, alloy, gold-aluminum alloy, or indium-aluminum alloy. 1.1.2 Standard comparison technique using pure gold, or gold-aluminum alloy, and 1.1.3 Secondary standard comparison techniques using pure indium, indium-aluminum alloy, pure dysprosium, or dysprosium-aluminum alloy. 1.2 The techniques presented are limited to measurements at room temperatures. However, special problems when making thermal-neutron fluence rate measurements in high-...

  5. Thermal conductivity measurement of the He-ion implanted layer of W using transient thermoreflectance technique

    Energy Technology Data Exchange (ETDEWEB)

    Qu, Shilian; Li, Yuanfei [Laboratory of Advanced Materials, School of Materials Science and Engineering, Tsinghua University, Beijing 100084 (China); Wang, Zhigang [Department of Electronic Engineering, Dalian University of Technology, Dalian 116024 (China); Jia, Yuzhen [Laboratory of Advanced Materials, School of Materials Science and Engineering, Tsinghua University, Beijing 100084 (China); Science and Technology on Reactor Fuel and Materials Laboratory, Nuclear Power Institute of China, Chengdu 610213 (China); Li, Chun [School of Mechanical and Materials Engineering, North China University of Technology, Beijing 100144 (China); Xu, Ben; Chen, Wanqi [Laboratory of Advanced Materials, School of Materials Science and Engineering, Tsinghua University, Beijing 100084 (China); Bai, Suyuan [School of Physics and Electronic Technology, Liaoning Normal University, Dalian 116029 (China); Huang, Zhengxing; Tang, Zhenan [Department of Electronic Engineering, Dalian University of Technology, Dalian 116024 (China); Liu, Wei, E-mail: liuw@mail.tsinghua.edu.cn [Laboratory of Advanced Materials, School of Materials Science and Engineering, Tsinghua University, Beijing 100084 (China)

    2017-02-15

    Transient thermoreflectance method was applied on the thermal conductivity measurement of the surface damaged layer of He-implanted tungsten. Uniform damages tungsten surface layer was produced by multi-energy He-ion implantation with thickness of 450 nm. Result shows that the thermal conductivity is reduced by 90%. This technique was further applied on sample with holes on the surface, which was produced by the He-implanted at 2953 K. The thermal conductivity decreases to 3% from the bulk value.

  6. Layout-Driven Post-Placement Techniques for Temperature Reduction and Thermal Gradient Minimization

    DEFF Research Database (Denmark)

    Liu, Wei; Calimera, Andrea; Macii, Alberto

    2013-01-01

    With the continuing scaling of CMOS technology, on-chip temperature and thermal-induced variations have become a major design concern. To effectively limit the high temperature in a chip equipped with a cost-effective cooling system, thermal specific approaches, besides low power techniques, are ...

  7. Review of simulation techniques for Aquifer Thermal Energy Storage (ATES)

    Science.gov (United States)

    Mercer, J. W.; Faust, C. R.; Miller, W. J.; Pearson, F. J., Jr.

    1981-03-01

    The analysis of aquifer thermal energy storage (ATES) systems rely on the results from mathematical and geochemical models. Therefore, the state-of-the-art models relevant to ATES were reviewed and evaluated. These models describe important processes active in ATES including ground-water flow, heat transport (heat flow), solute transport (movement of contaminants), and geochemical reactions. In general, available models of the saturated ground-water environment are adequate to address most concerns associated with ATES; that is, design, operation, and environmental assessment. In those cases where models are not adequate, development should be preceded by efforts to identify significant physical phenomena and relate model parameters to measurable quantities.

  8. DISSECTING THE GRAVITATIONAL LENS B1608+656. I. LENS POTENTIAL RECONSTRUCTION

    NARCIS (Netherlands)

    Suyu, S. H.; Marshall, P. J.; Blandford, R. D.; Fassnacht, C. D.; Koopmans, L. V. E.; McKean, J. P.; Treu, T.

    2009-01-01

    Strong gravitational lensing is a powerful technique for probing galaxy mass distributions and for measuring cosmological parameters. Lens systems with extended source-intensity distributions are particularly useful for this purpose since they provide additional constraints on the lens potential (

  9. Hot filament technique for measuring the thermal conductivity of molten lithium fluoride

    Science.gov (United States)

    Jaworske, Donald A.; Perry, William D.

    1990-01-01

    Molten salts, such as lithium fluoride, are attractive candidates for thermal energy storage in solar dynamic space power systems because of their high latent heat of fusion. However, these same salts have poor thermal conductivities which inhibit the transfer of heat into the solid phase and out of the liquid phase. One concept for improving the thermal conductivity of the thermal energy storage system is to add a conductive filler material to the molten salt. High thermal conductivity pitch-based graphite fibers are being considered for this application. Although there is some information available on the thermal conductivity of lithium fluoride solid, there is very little information on lithium fluoride liquid, and no information on molten salt graphite fiber composites. This paper describes a hot filament technique for determining the thermal conductivity of molten salts. The hot filament technique was used to find the thermal conductivity of molten lithium fluoride at 930 C, and the thermal conductivity values ranged from 1.2 to 1.6 W/mK. These values are comparable to the slightly larger value of 5.0 W/mK for lithium fluoride solid. In addition, two molten salt graphite fiber composites were characterized with the hot filament technique and these results are also presented.

  10. Thermal analysis of cracked bodies using finite element techniques

    International Nuclear Information System (INIS)

    Hellen, T.K.; Price, R.H.; Harrison, R.P.

    1975-01-01

    The paper develops the potential energy equation in terms of finite element theory including thermal loads. Following this, the energy release rate and consequently the stress intensity factors are derived. Considerations of the classical near crack tip equations are made and deficiencies with the popular substitution methods are highlighted. A method of removing these deficiencies is described. Various energy methods are reconsidered in terms of the role of the thermal energy contribution to the potential energy. These methods include work of crack closure, energy compliance and virtual crack extensions with no other change in nodal geometry, and therefore only requires the recalculation of the stiffness matrices of the crack tip elements. An example of a quadratic temperature gradient parallel to the crack plane in an edge cracked plate is described. Comparisons of the various finite element methods are made and generally show good agreement. A second application compares the virtual crack extension method with an approximate analytical solution in determining stress intensity factors for a thick hollow cylinder with an axial crack for various depths through the wall thickness and for different times. Initially the cylinder is at a uniform high temperature and is then subjected to a sustained cooling shock. Analytical solutions are available for temperature and stress distributions in the uncracked pipe. The stress intensity for a shallow crack in the early stages of the transient has been determined using a superposition procedure. Comparison of the analytical and computed results shows good agreement between the methods

  11. Investigation of Thermal Interface Materials Using Phase-Sensitive Transient Thermoreflectance Technique: Preprint

    Energy Technology Data Exchange (ETDEWEB)

    Feng, X.; King, C.; DeVoto, D.; Mihalic, M.; Narumanchi, S.

    2014-08-01

    With increasing power density in electronics packages/modules, thermal resistances at multiple interfaces are a bottleneck to efficient heat removal from the package. In this work, the performance of thermal interface materials such as grease, thermoplastic adhesives and diffusion-bonded interfaces are characterized using the phase-sensitive transient thermoreflectance technique. A multi-layer heat conduction model was constructed and theoretical solutions were derived to obtain the relation between phase lag and the thermal/physical properties. This technique enables simultaneous extraction of the contact resistance and bulk thermal conductivity of the TIMs. With the measurements, the bulk thermal conductivity of Dow TC-5022 thermal grease (70 to 75 um bondline thickness) was 3 to 5 W/(m-K) and the contact resistance was 5 to 10 mm2-K/W. For the Btech thermoplastic material (45 to 80 μm bondline thickness), the bulk thermal conductivity was 20 to 50 W/(m-K) and the contact resistance was 2 to 5 mm2-K/W. Measurements were also conducted to quantify the thermal performance of diffusion-bonded interface for power electronics applications. Results with the diffusion-bonded sample showed that the interfacial thermal resistance is more than one order of magnitude lower than those of traditional TIMs, suggesting potential pathways to efficient thermal management.

  12. Review of simulation techniques for aquifer thermal energy storage (ATES)

    Energy Technology Data Exchange (ETDEWEB)

    Mercer, J.W.; Faust, C.R.; Miller, W.J.; Pearson, F.J. Jr.

    1981-03-01

    The storage of thermal energy in aquifers has recently received considerable attention as a means to conserve and more efficiently use energy supplies. The analysis of aquifer thermal energy storage (ATES) systems will rely on the results from mathematical and geochemical models. Therefore, the state-of-the-art models relevant to ATES was reviewed and evaluated. These models describe important processes active in ATES including ground-water flow, heat transport (heat flow), solute transport (movement of contaminants), and geochemical reactions. In general, available models of the saturated ground-water environment are adequate to address most concerns associated with ATES; that is, design, operation, and environmental assessment. In those cases where models are not adequate, development should be preceded by efforts to identify significant physical phenomena and relate model parameters to measurable quantities. Model development can then proceed with the expectation of an adequate data base existing for the model's eventual use. Review of model applications to ATES shows that the major emphasis has been on generic sensitivity analysis and site characterization. Assuming that models are applied appropriately, the primary limitation on model calculations is the data base used to construct the model. Numerical transport models are limited by the uncertainty of subsurface data and the lack of long-term historical data for calibration. Geochemical models are limited by the lack of thermodynamic data for the temperature ranges applicable to ATES. Model applications undertaken with data collection activities on ATES sites should provide the most important contributions to the understanding and utilization of ATES. Therefore, the primary conclusion of this review is that model application to field sites in conjunction with data collection activities is essential to the development of this technology.

  13. Non-destructive high-resolution thermal imaging techniques to evaluate wildlife and delicate biological samples

    International Nuclear Information System (INIS)

    Lavers, C; Franklin, P; Franklin, P; Plowman, A; Sayers, G; Bol, J; Shepard, D; Fields, D

    2009-01-01

    Thermal imaging cameras now allows routine monitoring of dangerous yet endangered wildlife in captivity. This study looks at the potential applications of radiometrically calibrated thermal data to wildlife, as well as providing parameters for future materials applications. We present a non-destructive active testing technique suitable for enhancing imagery contrast of thin or delicate biological specimens yielding improved thermal contrast at room temperature, for analysis of sample thermal properties. A broad spectrum of animals is studied with different textured surfaces, reflective and emissive properties in the infra red part of the electromagnetic spectrum. Some surface features offer biomimetic materials design opportunities.

  14. Non-destructive high-resolution thermal imaging techniques to evaluate wildlife and delicate biological samples

    Energy Technology Data Exchange (ETDEWEB)

    Lavers, C; Franklin, P; Franklin, P; Plowman, A; Sayers, G; Bol, J; Shepard, D; Fields, D, E-mail: brnc-radarcomms1@nrta.mod.u [Sensors Team, Plymouth University at Britannia Royal Naval College, Dartmouth, Devon (United Kingdom) and Paignton Zoological Park, Paignton, Devon (United Kingdom); Thermal Wave Imaging, Inc., 845 Livernoise St, Ferndale, MI (United States); Buckfast Butterfly and Otter Sanctuary, Buckfast, Devon (United Kingdom)

    2009-07-01

    Thermal imaging cameras now allows routine monitoring of dangerous yet endangered wildlife in captivity. This study looks at the potential applications of radiometrically calibrated thermal data to wildlife, as well as providing parameters for future materials applications. We present a non-destructive active testing technique suitable for enhancing imagery contrast of thin or delicate biological specimens yielding improved thermal contrast at room temperature, for analysis of sample thermal properties. A broad spectrum of animals is studied with different textured surfaces, reflective and emissive properties in the infra red part of the electromagnetic spectrum. Some surface features offer biomimetic materials design opportunities.

  15. High-performance thermal cutting techniques for underwater use

    International Nuclear Information System (INIS)

    Bach, F.W.

    2002-01-01

    Over the past few years, the Institute for Materials Research of the University of Hanover developed a new product family (Contact-Arc-Metal-X) of electrothermal techniques for underwater cutting of metal structures. This CAMX technology comprises contact arc metal cutting by means of a sword-shaped electrode, contact arc metal grinding with a rotating electrode, and contact arc metal drilling with an integrated interlocking mechanism. CAMC is characterized by its capability to cut components with complex structures. Undercuts and cavities constitute no obstacles in the process. CAMG is a technique for straight cutting characterized by its high cutting speeds. CAMD is able to produce countersunk boreholes and holes of any geometry. The integrated tensioning mechanism allows parts to be gripped and transported which could not be handled by conventional gripper systems. (orig.) [de

  16. Development of Processing Techniques for Advanced Thermal Protection Materials

    Science.gov (United States)

    Selvaduray, Guna; Cox, Michael; Srinivasan, Vijayakumar

    1997-01-01

    Thermal Protection Materials Branch (TPMB) has been involved in various research programs to improve the properties and structural integrity of the existing aerospace high temperature materials. Specimens from various research programs were brought into the analytical laboratory for the purpose of obtaining and refining the material characterization. The analytical laboratory in TPMB has many different instruments which were utilized to determine the physical and chemical characteristics of materials. Some of the instruments that were utilized by the SJSU students are: Scanning Electron Microscopy (SEM), Energy Dispersive X-ray analysis (EDX), X-ray Diffraction Spectrometer (XRD), Fourier Transform-Infrared Spectroscopy (FTIR), Ultra Violet Spectroscopy/Visible Spectroscopy (UV/VIS), Particle Size Analyzer (PSA), and Inductively Coupled Plasma Atomic Emission Spectrometer (ICP-AES). The above mentioned analytical instruments were utilized in the material characterization process of the specimens from research programs such as: aerogel ceramics (I) and (II), X-33 Blankets, ARC-Jet specimens, QUICFIX specimens and gas permeability of lightweight ceramic ablators. In addition to analytical instruments in the analytical laboratory at TPMB, there are several on-going experiments. One particular experiment allows the measurement of permeability of ceramic ablators. From these measurements, physical characteristics of the ceramic ablators can be derived.

  17. Study of Lactic Acid Thermal Behavior Using Thermoanalytical Techniques

    Directory of Open Access Journals (Sweden)

    Andrea Komesu

    2017-01-01

    Full Text Available Actually, there is a growing interest in the biotechnological production of lactic acid by fermentation aiming to substitute fossil fuel routes. The development of an efficient method for its separation and purification from fermentation broth is very important to assure the economic viability of production. Due to its high reactivity and tendency to decompose at high temperatures, the study of lactic acid thermal behavior is essential for its separation processes and potential application. In the present study, differential scanning calorimetry (DSC analyses showed endothermic peaks related to the process of evaporation. Data of thermogravimetry (TG/DTG were correlated to Arrhenius and Kissinger equations to provide the evaporation kinetic parameters and used to determine the vaporization enthalpy. Activation energies were 51.08 and 48.37 kJ·mol−1 and frequency values were 859.97 and 968.81 s−1 obtained by Arrhenius and Kissinger equations, respectively. Thermogravimetry, coupled with mass spectroscopy (TG-MS, provided useful information about decomposition products when lactic acid was heated at 573 K for approximately 30 min.

  18. Evaluation of Candidate In-Pile Thermal Conductivity Techniques

    International Nuclear Information System (INIS)

    Fox, B.; Ban, H.; Daw, J.; Condie, K.; Knudson, D.; Rempe, J.

    2009-01-01

    Thermophysical properties of materials must be known for proper design, test, and application of new fuels and structural properties in nuclear reactors. In the case of nuclear fuels during irradiation, the physical structure and chemical composition change as a function of time and position within the rod. Typically, thermal conductivity changes, as well as other thermophysical properties being evaluated during irradiation in a materials and test reactor, are measured out-of-pile in 'hot-cells'. Repeatedly removing samples from a test reactor to make out-of-pile measurements is expensive, has the potential to disturb phenomena of interest, and only provide understanding of the sample's end state at the time each measurement is made. There are also limited thermophysical property data for advanced fuels. Such data are needed for the development of next generation reactors and advanced fuels for existing nuclear plants. Having the capacity to effectively and quickly characterize fuels and material properties during irradiation has the potential to improve the fidelity of nuclear fuel data and reduce irradiation testing costs

  19. Thermal Diffusivity Measurement for p-Si and Ag/p-Si by Photoacoustic Technique

    Science.gov (United States)

    Hussein, Mohammed Jabbar; Yunus, W. Mahmood Mat; Kamari, Halimah Mohamed; Zakaria, Azmi

    2015-10-01

    Thermal diffusivity (TD) of p-Si and Ag/p-Si samples were measured by photoacoustic technique using open photoacoustic cell (OPC). The samples were annealed by heating them at 960, 1050, 1200, and 1300 °C for 3 h in air. The thermal diffusivity of Ag-coated samples was obtained by fitting the photoacoustic experimental data to the thermally thick equation for Rosencwaig and Gersho (RG) theory. For the single layer samples, the thermal diffusivity can be obtained by fitting as well as by obtaining the critical frequency f c . In this study, the thermal diffusivity of the p-Si samples increased with increasing the annealing temperature. The thermal diffusivity of the Ag/p-Si samples, after reaching the maximum value of about 2.73 cm2/s at a temperature of 1200 °C, decreased due to the silver complete melt in the surface of the silicon.

  20. Advanced kinetics for calorimetric techniques and thermal stability screening of sulfide minerals

    International Nuclear Information System (INIS)

    Iliyas, Abduljelil; Hawboldt, Kelly; Khan, Faisal

    2010-01-01

    Thermal methods of analysis such as differential scanning calorimetry (DSC) provide a powerful methodology for the study of solid reactions. This paper proposes an improved thermal analysis methodology for thermal stability investigation of complex solid-state reactions. The proposed methodology is based on differential iso-conversional approach and involves peak separation, individual peak analysis and combination of isothermal/non-isothermal DSC measurements for kinetic analysis and prediction. The proposed thermal analysis, which coupled with Mineral Libration Analyzer (MLA) technique was employed to investigate thermal behavior of sulfide mineral oxidation. The importance of various experimental variables such as particle size, heating rate and atmosphere were investigated and discussed. The information gained from such an advanced thermal analysis method is useful for scale-up processes with potential of significant savings in plant operations, as well as in mitigating adverse environmental and safety issues arising from handling and storage of sulfide minerals.

  1. Thermal diffusivity measurement for p-Si and Ag/p-Si by photoacoustic technique

    Energy Technology Data Exchange (ETDEWEB)

    Hussein, Mohammed Jabbar; Yunus, W. Mahmood Mat; Kamari, Halimah Mohamed; Zakaria, Azmi, E-mail: mohammed55865@yahoo.com [Department of Physics, Faculty of Science, Universiti PutraMalaysia (UPM), Serdang (Malaysia)

    2015-10-15

    Thermal diffusivity (TD) of p-Si and Ag/p-Si samples were measured by photoacoustic technique using open photoacoustic cell (OPC). The samples were annealed by heating them at 960, 1050, 1200, and 1300 °C for 3 h in air. The thermal diffusivity of Ag-coated samples was obtained by fitting the photoacoustic experimental data to the thermally thick equation for Rosencwaig and Gersho (RG) theory. For the single layer samples, the thermal diffusivity can be obtained by fitting as well as by obtaining the critical frequency f{sub c.} In this study, the thermal diffusivity of the p-Si samples increased with increasing the annealing temperature. The thermal diffusivity of the Ag/p-Si samples, after reaching the maximum value of about 2.73 cm{sup 2}/s at a temperature of 1200 °C, decreased due to the silver complete melt in the surface of the silicon. (author)

  2. High-precision numerical simulation with autoadaptative grid technique in nonlinear thermal diffusion

    International Nuclear Information System (INIS)

    Chambarel, A.; Pumborios, M.

    1992-01-01

    This paper reports that many engineering problems concern the determination of a steady state solution in the case with strong thermal gradients, and results obtained using the finite-element technique are sometimes inaccurate, particularly for nonlinear problems with unadapted meshes. Building on previous results in linear problems, we propose an autoadaptive technique for nonlinear cases that uses quasi-Newtonian iterations to reevaluate an interpolation error estimation. The authors perfected an automatic refinement technique to solve the nonlinear thermal problem of temperature calculus in a cast-iron cylinder head of a diesel engine

  3. Laser/fluorescent dye flow visualization technique developed for system component thermal hydraulic studies

    International Nuclear Information System (INIS)

    Oras, J.J.; Kasza, K.E.

    1988-01-01

    A novel laser flow visualization technique is presented together with examples of its use in visualizing complex flow patterns and plans for its further development. This technique has been successfully used to study (1) the flow in a horizontal pipe subject to temperature transients, to view the formation and breakup of thermally stratified flow and to determine instantaneous velocity distributions in the same flow at various axial locations; (2) the discharge of a stratified pipe flow into a plenum exhibiting a periodic vortex pattern; and (3) the thermal-buoyancy-induced flow channeling on the shell side of a heat exchanger with glass tubes and shell. This application of the technique to heat exchangers is unique. The flow patterns deep within a large tube bundle can be studied under steady or transient conditions. This laser flow visualization technique constitutes a very powerful tool for studying single or multiphase flows in complex thermal system components

  4. Work in progress. Transcatheter thermal venous occlusion: a new technique

    International Nuclear Information System (INIS)

    Rholl, K.S.; Rysavy, J.A.; Vlodaver, Z.; Cragg, A.H.; Castaneda-Zuniga, W.R.; Amplatz, K.

    1982-01-01

    Diatrizoate (76%) contrast agent heated to 100 0 C was injected into the veins of dogs and one human volunteer for the nonsurgical occlusion of the vessels. Follow-up venograms and histologic examinations, at intervals varying from one day to four weeks later, revealed thrombosis of the injected veins in all animals. Thrombosis occurred one to five days after injection of contrast agent. The authors conclude that hot contrast medium is a safe and convenient agent for inducing thrombosis. It is much easier to use than mechanical devices, tissue glues, and plastics, which involve complex procedures and specialized equipment. In contrast to other sclerosing agents, hot contrast agent is rapidly converted into a nonsclerosing agent by cooling. The new technique allows a more controlled thremal injury to the vascular wall and is under fluoroscopic control

  5. Measurement of Thermal Properties of Triticale Starch Films Using Photothermal Techniques

    Science.gov (United States)

    Correa-Pacheco, Z. N.; Cruz-Orea, A.; Jiménez-Pérez, J. L.; Solorzano-Ojeda, S. C.; Tramón-Pregnan, C. L.

    2015-06-01

    Nowadays, several commercially biodegradable materials have been developed with mechanical properties similar to those of conventional petrochemical-based polymers. These materials are made from renewable sources such as starch, cellulose, corn, and molasses, being very attractive for numerous applications in the plastics, food, and paper industries, among others. Starches from maize, rice, wheat, and potato are used in the food industry. However, other types of starches are not used due to their low protein content, such as triticale. In this study, starch films, processed using a single screw extruder with different compositions, were thermally and structurally characterized. The thermal diffusivity, thermal effusivity, and thermal conductivity of the biodegradable films were determined using photothermal techniques. The thermal diffusivity was measured using the open photoacoustic cell technique, and the thermal effusivity was obtained by the photopyroelectric technique in an inverse configuration. The results showed differences in thermal properties for the films. Also, the films microstructures were observed by scanning electron microscopy, transmission electron microscopy, and the crystalline structure determined by X-ray diffraction.

  6. Lens Model

    DEFF Research Database (Denmark)

    Nash, Ulrik William

    2014-01-01

    Firms consist of people who make decisions to achieve goals. How do these people develop the expectations which underpin the choices they make? The lens model provides one answer to this question. It was developed by cognitive psychologist Egon Brunswik (1952) to illustrate his theory of probabil...

  7. Effects of thermal and fast neutrons and of ENU on generations M3 and M4 of Lens culinaris (medicus)

    International Nuclear Information System (INIS)

    Uhlik, J.; Urban, J.

    1976-01-01

    Plants in which the selection of the most fertile plants had not been made in the preceding generations showed a significantly lower emergence rate in the M3 and M4 generation after an ethyl nitroso urea (ENU) application, in comparison with material treated with neutrons. In the evaluation of the plants obtained after an exposure to the most effective doses in the induction of chlorophyll mutants, significant differences of the average values in relation to the control were found in the M3 generation in the number of seeds per plant after the application of both neutron radiations and ENU. In addition, after the application of thermal neutrons and ENU a significant difference was found in the average values of plant weight. A difference in the overall range of variability in relation to the control was found in plant weight after the application of neutrons and ENU, and in seed weight after the application of ENU and fast neutrons. The differences between the treated plants and controls in the M4 generation plants with fusarium disease were insignificant. The evaluation of the progenies exposed to various doses of the highest mutation effectiveness showed in the M3 generation significant differences (in relation to the control) in the mean values of plant height, seed weight, plant weight, seed proportion in plants, in the bottom-pod insertion level, and in the number of pods set. Despite a considerable attack by fusarium disease, the greatest number of plants having more seeds than 50 was selected in the M4 generation of the material exposed to the dose of 8 fast neutrons (0.95% of plants) while in the control the proportion of highly fertile plants was only 0.05%. The widest range of overall variability in the characteristics under study was found after irradiation with thermal neutrons. From this viewpoint they can be recommended for wide practical utilization. (author)

  8. Comparative study of linear and nonlinear ultrasonic techniques for evaluation thermal damage of tube like structures

    International Nuclear Information System (INIS)

    Li, Weibin; Cho, Younho; Li, Xianqiang

    2013-01-01

    Ultrasonic guided wave techniques have been widely used for long range nondestructive detection in tube like structures. The present paper investigates the ultrasonic linear and nonlinear parameters for evaluating the thermal damage in aluminum pipe. Specimens were subjected to thermal loading. Flexible polyvinylidene fluoride (PVDF) comb transducers were used to generate and receive the ultrasonic waves. The second harmonic wave generation technique was used to check the material nonlinearity change after different heat loadings. The conventional linear ultrasonic approach based on attenuation was also used to evaluate the thermal damages in specimens. The results show that the proposed experimental setup is viable to assess the thermal damage in an aluminum pipe. The ultrasonic nonlinear parameter is a promising candidate for the prediction of micro damages in a tube like structure

  9. Plasma diagnostic techniques in thermal-barrier tandem-mirror fusion experiments

    International Nuclear Information System (INIS)

    Silver, E.H.; Clauser, J.F.; Carter, M.R.; Failor, B.H.; Foote, J.H.; Hornady, R.S.; James, R.A.; Lasnier, C.J.; Perkins, D.E.

    1986-01-01

    We review two classes of plasma diagnostic techniques used in thermal-barrier tandem-mirror fusion experiments. The emphasis of the first class is to study mirror-trapped electrons at the thermal-barrier location. The focus of the second class is to measure the spatial and temporal behavior of the plasma space potential at various axial locations. The design and operation of the instruments in these two categories are discussed and data that are representative of their performance is presented

  10. Thermal characterisation of ceramic/metal joining techniques for fusion applications using X-ray tomography

    Energy Technology Data Exchange (ETDEWEB)

    Evans, Ll.M., E-mail: llion.evans@ccfe.ac.uk [School of Materials, University of Manchester, Grosvenor Street, Manchester M1 7HS (United Kingdom); Margetts, L. [School of Earth, Atmospheric and Environmental Sciences, University of Manchester, Williamson Building, Manchester M13 9PL (United Kingdom); Casalegno, V. [Department of Applied Science and Technology, Politecnico di Torino, Corso Duca degli Abruzzi 24, I-10129 Torino (Italy); Leonard, F.; Lowe, T.; Lee, P.D. [School of Materials, University of Manchester, Grosvenor Street, Manchester M1 7HS (United Kingdom); Schmidt, M.; Mummery, P.M. [School of Mechanical, Aerospace and Civil Engineering (MACE), University of Manchester, Manchester M13 9PL (United Kingdom)

    2014-06-15

    This work investigates the thermal performance of four novel CFC–Cu joining techniques. Two involve direct casting and brazing of Cu onto a chromium modified CFC surface, the other two pre-coat a brazing alloy with chromium using galvanisation and sputtering processes. The chromium carbide layer at the interface has been shown to improve adhesion. Thermal conductivity across the join interface was measured by laser flash analysis. X-ray tomography was performed to investigate micro-structures that might influence the thermal behaviour. It was found that thermal conductivity varied by up to 72%. Quantification of the X-ray tomography data showed that the dominant feature in reducing thermal conductivity was the lateral spread of voids at the interface. Correlations were made to estimate the extent of this effect.

  11. SU-E-J-11: Measurement of Eye Lens Dose for Varian On-Board Imaging with Different CBCT Acquisition Techniques

    International Nuclear Information System (INIS)

    Deshpande, S; Dhote, D; Kumar, R; Thakur, K

    2015-01-01

    Purpose: To measure actual patient eye lens dose for different cone beam computed tomography (CBCT) acquisition protocol of Varian’s On Board Imagining (OBI) system using Optically Stimulated Luminescence (OSL) dosimeter and study the eye lens dose with patient geometry and distance of isocenter to the eye lens Methods: OSL dosimeter was used to measure eye lens dose of patient. OSL dosimeter was placed on patient forehead center during CBCT image acquisition to measure eye lens dose. For three different cone beam acquisition protocol (standard dose head, low dose head and high quality head) of Varian On-Board Imaging, eye lens doses were measured. Measured doses were correlated with patient geometry and distance between isocenter to eye lens. Results: Measured eye lens dose for standard dose head was in the range of 1.8 mGy to 3.2 mGy, for high quality head protocol dose was in range of 4.5mGy to 9.9 mGy whereas for low dose head was in the range of 0.3mGy to 0.7mGy. Dose to eye lens is depends upon position of isocenter. For posterioraly located tumor eye lens dose is less. Conclusion: From measured doses it can be concluded that by proper selection of imagining protocol and frequency of imaging, it is possible to restrict the eye lens dose below the new limit set by ICRP. However, undoubted advantages of imaging system should be counter balanced by careful consideration of imaging protocol especially for very intense imaging sequences for Adoptive Radiotherapy or IMRT

  12. Measuring thermal conductivity of polystyrene nanowires using the dual-cantilever technique.

    Science.gov (United States)

    Canetta, Carlo; Guo, Samuel; Narayanaswamy, Arvind

    2014-10-01

    Thermal conductance measurements are performed on individual polystyrene nanowires using a novel measurement technique in which the wires are suspended between two bi-material microcantilever sensors. The nanowires are fabricated via electrospinning process. Thermal conductivity of the nanowire samples is found to be between 6.6 and 14.4 W m(-1) K(-1) depending on sample, a significant increase above typical bulk conductivity values for polystyrene. The high strain rates characteristic of electrospinning are believed to lead to alignment of molecular polymer chains, and hence the increase in thermal conductivity, along the axis of the nanowire.

  13. A review of second law techniques applicable to basic thermal science research

    Science.gov (United States)

    Drost, M. Kevin; Zamorski, Joseph R.

    1988-11-01

    This paper reports the results of a review of second law analysis techniques which can contribute to basic research in the thermal sciences. The review demonstrated that second law analysis has a role in basic thermal science research. Unlike traditional techniques, second law analysis accurately identifies the sources and location of thermodynamic losses. This allows the development of innovative solutions to thermal science problems by directing research to the key technical issues. Two classes of second law techniques were identified as being particularly useful. First, system and component investigations can provide information of the source and nature of irreversibilities on a macroscopic scale. This information will help to identify new research topics and will support the evaluation of current research efforts. Second, the differential approach can provide information on the causes and spatial and temporal distribution of local irreversibilities. This information enhances the understanding of fluid mechanics, thermodynamics, and heat and mass transfer, and may suggest innovative methods for reducing irreversibilities.

  14. Synthesis and Thermal Characterization of Hydroxyapatite Powders Obtained by Sol-Gel Technique

    Science.gov (United States)

    Jiménez-Flores, Y.; Camacho, N.; Rojas-Trigos, J. B.; Suárez, M.

    The development of bioactive materials presents an interesting and an extremely relevant problem to solve, in the development of customized cranial and maxillofacial prosthesis, bioactive coating, and cements, for example. In such areas, one of the more employed materials is the synthetic hydroxyapatite, due to its proved biocompatibility with the human body; however, there are few studies about the thermal affinity with the biological surroundings, and most of them are centered in the thermal stability of the hydroxyapatite instead of its transient thermal response. In the present paper, the synthesis and physical-chemical characterization of hydroxyapatite samples, obtained by the sol-gel technique employing ultrasonic mixing, are reported. Employing X-ray diffraction patterns, XEDS and FTIR spectra, the crystal symmetry, chemical elements, and the present functional groups of the studied samples were determined and found to correspond to those reported in the literature, with a stoichiometry close to the ideal for biological applications. Additionally, by means of the photoacoustic detection and infrared photothermal radiometry (IPTR) techniques, the thermal response of the samples was obtained. Analyzing the photoacoustic data, the synthetized samples show photoacoustic opaqueness, responding in the thermally thick regime in the measurement range, and their thermal effusivity was also determined, having values of 1.47 folds the thermal effusivity of the mandibular human bone. Finally, from the IPTR measurements, the thermal diffusivity and thermal conductivity of the samples were also determined, having good agreement with the reported values for synthetic hydroxyapatite. The structural and thermophysical properties of the here reported samples show that the synthesized samples have good thermal affinity with the mandibular human bone tissue, and are suitable for biomedical applications.

  15. Temperature-dependent thermal conductivity of flexible yttria-stabilized zirconia substrate via 3ω technique

    Energy Technology Data Exchange (ETDEWEB)

    Singh, Shivkant; Yarali, Milad; Mavrokefalos, Anastassios [Department of Mechanical Engineering, University of Houston, Houston, TX (United States); Shervin, Shahab [Materials Science and Engineering Program, University of Houston, Houston, TX (United States); Venkateswaran, Venkat; Olenick, Kathy; Olenick, John A. [ENrG Inc., Buffalo, NY (United States); Ryou, Jae-Hyun [Department of Mechanical Engineering, University of Houston, Houston, TX (United States); Materials Science and Engineering Program, University of Houston, Houston, TX (United States); Texas Center for Superconductivity, University of Houston (TcSUH), Houston, TX (United States)

    2017-10-15

    Thermal management in flexible electronic has proven to be challenging thereby limiting the development of flexible devices with high power densities. To truly enable the technological implementation of such devices, it is imperative to develop highly thermally conducting flexible substrates that are fully compatible with large-scale fabrication. Here, we present the thermal conductivity of state-of-the-art flexible yttria-stabilized zirconia (YSZ) substrates measured using the 3ω technique, which is already commercially manufactured via roll-to-roll technique. We observe that increasing the grain size increases the thermal conductivity of the flexible 3 mol.% YSZ, while the flexibility and transparency of the sample are hardly affected by the grain size enlargement. We exhibit thermal conductivity values of up to 4.16 Wm{sup -1}K {sup -1} that is at least 4 times higher than state-of-the-art polymeric flexible substrates. Phonon-hopping model (PHM) for granular material was used to fit the measured thermal conductivity and accurately define the thermal transport mechanism. Our results show that through grain size optimization, YSZ flexible substrates can be realized as flexible substrates, that pave new avenues for future novel application in flexible electronics through the utilization of both their ceramic structural flexibility and high heat dissipating capability. (copyright 2017 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  16. Contact lens surface by electron beam

    International Nuclear Information System (INIS)

    Shin, Jung Hyuck; Lee, Suk Ju; Hwang, Kwang Ha; Jeon Jin

    2011-01-01

    Contact lens materials needs good biocompatibility, high refractive index, high optical transparency, high water content etc. Surface treat method by using plasma and radiation can modify the physical and/or chemical properties of the contact lens surface. Radiation technology such as electron beam irradiation can apply to polymerization reaction and enhance the functionality of the polymer.The purpose of this study is to modify of contact lens surface by using Eb irradiation technology. Electron beam was irradiated to the contact lens surface which was synthesized thermal polymerization method and commercial contact lens to modify physical and chemical properties. Ft-IR, XP, UV-vis spectrophotometer, water content, oxygen trans-metastability were used to characterize the surface state, physicochemical, and optical property of the contact lens treated with Eb. The water content and oxygen transmissibility of the contact lens treated with Eb were increased due to increase in the hydrophilic group such as O-C=O and OH group on the contact lens surface which could be produced by possible reaction between carbon and oxygen during the Eb irradiation. All of the lenses showed the high optical transmittance above 90%. In this case of B/Es, TES, Ti contact lens, the optical transmittance decreased about 5% with increasing Eb dose in the wavelength of UV-B region. The contact lens modified by Eb irradiation could improve the physical properties of the contact lens such as water content and oxygen transmissibility

  17. Metallographic examination of TD-nickel base alloys. [thermal and chemical etching technique evaluation

    Science.gov (United States)

    Kane, R. D.; Petrovic, J. J.; Ebert, L. J.

    1975-01-01

    Techniques are evaluated for chemical, electrochemical, and thermal etching of thoria dispersed (TD) nickel alloys. An electrochemical etch is described which yielded good results only for large grain sizes of TD-nickel. Two types of thermal etches are assessed for TD-nickel: an oxidation etch and vacuum annealing of a polished specimen to produce an etch. It is shown that the first etch was somewhat dependent on sample orientation with respect to the processing direction, the second technique was not sensitive to specimen orientation or grain size, and neither method appear to alter the innate grain structure when the materials were fully annealed prior to etching. An electrochemical etch is described which was used to observe the microstructures in TD-NiCr, and a thermal-oxidation etch is shown to produce better detail of grain boundaries and to have excellent etching behavior over the entire range of grain sizes of the sample.

  18. Measuring technique of super high temperature thermal properties of reactor core materials

    International Nuclear Information System (INIS)

    Ono, Akira; Baba, Tetsuya; Watanabe, Hideo; Matsumoto, Tsuyoshi

    1998-01-01

    In this study, thermal properties of reactor core materials used for water cooled reactors and FBR were tried to develop a technique to measure their melt states at less than 3,000degC in order to contribute more correct evaluation of the reactor core behavior at severe accident. Then, a thermal property measuring method of high temperature melt by using floating method was investigated and its fundamental design was begun to investigate under a base of optimum judgement on the air flow floating throw-down method. And, in order to measure emissivity of melt specimen surface essential for correct temperature measurement using the throw down method, a spectroscopic emissivity measuring unit using an ellipsometer was prepared and induced. On the thermal properties measurement using the holding method, a specimen container to measure thermal diffusiveness of the high temperature melts by using laser flashing method was tried to prepare. (G.K.)

  19. Self-consistent photothermal techniques: Application for measuring thermal diffusivity in vegetable oils

    Science.gov (United States)

    Balderas-López, J. A.; Mandelis, Andreas

    2003-01-01

    The thermal wave resonator cavity (TWRC) was used to measure the thermal properties of vegetable oils. The thermal diffusivity of six commercial vegetable oils (olive, corn, soybean, canola, peanut, and sunflower) was measured by means of this device. A linear relation between both the amplitude and phase as functions of the cavity length for the TWRC was observed and used for the measurements. Three significant figure precisions were obtained. A clear distinction between extra virgin olive oil and other oils in terms of thermal diffusivity was shown. The high measurement precision of the TWRC highlights the potential of this relatively new technique for assessing the quality of this kind of fluids in terms of their thermophysical properties.

  20. Optimization of Thermal Aspects of Friction Stir Welding – Initial Studies Using a Space Mapping Technique

    DEFF Research Database (Denmark)

    Larsen, Anders Astrup; Bendsøe, Martin P.; Schmidt, Henrik Nikolaj Blicher

    2007-01-01

    The aim of this paper is to optimize a thermal model of a friction stir welding process. The optimization is performed using a space mapping technique in which an analytical model is used along with the FEM model to be optimized. The results are compared to traditional gradient based optimization...

  1. Antimicrobial properties of uncapped silver nanoparticles synthesized by DC arc thermal plasma technique.

    Science.gov (United States)

    Shinde, Manish; Patil, Rajendra; Karmakar, Soumen; Bhoraskar, Sudha; Rane, Sunit; Gade, Wasudev; Amalnerkar, Dinesh

    2012-02-01

    We, herein, report the antimicrobial properties of uncapped silver nanoparticles for a Gram positive model organism, Bacillus subtilis. Uncapped silver nanoparticles have been prepared using less-explored DC arc thermal plasma technique by considering its large scale generation capability. It is observed that the resultant nanoparticles show size as well as optical property dependent antimicrobial effect.

  2. Thermal property characterization of fine fibers by the 3-omega technique

    International Nuclear Information System (INIS)

    Xing, Changhu; Jensen, Colby; Munro, Troy; White, Benjamin; Ban, Heng; Chirtoc, Mihai

    2014-01-01

    The 3 omega method is one of few reliable measurement techniques for thermal characterization of micro to nanoscale suspended wires or fibers and has been applied for measurements of carbon nanotubes and silicon nanowires. However, the models described in the past were either complicated for analysis or simplified from a more complete solution. In addition, the past models cannot be implemented directly when using a more reliable measurement configuration with a Wheatstone bridge. In this work, a simpler, explicit model, is developed to describe the heat transfer process through a suspended wire for measurement of its thermal properties. Generic trends and values of the 3ω harmonic voltage amplitude and phase responses clearly indicate the frequency limits for thermal conductivity and heat capacity determination and ideal conditions for thermal diffusivity estimation. Based on a sensitivity analysis, these limits are confirmed and appropriate frequency ranges for thermal conductivity and diffusivity are recommended. Radiation influence on the measurement results is quantified and correlated to a dimensionless radiation parameter. Two methods are presented to determine sample thermal properties independent of lateral heat losses and validated by numerical experiments using COMSOL. Uncertainty analysis was also derived by Taylor series expansion with calculated parameter sensitivities. - Highlights: • An improved model for suspended wire 3 omega measurement. • Quantification on the radiation induced measurement error. • Numerical simulation validating the improved model. • Sensitivity analysis to find measurement range minimizing uncertainty

  3. Synthesis of {gamma}-aluminium oxynitride spinel using thermal plasma technique

    Energy Technology Data Exchange (ETDEWEB)

    Panda, Pravuram; Singh, S. K.; Sinha, S. P. [School of Applied Science (Physics), KIIT University, Bhubaneswar 751024 (India); Advanced Materials Technology Department, IMMT (CSIR), Bhubaneswar 751013 (India); School of Applied Science (Physics), KIIT University, Bhubaneswar 751024 (India)

    2012-07-23

    The synthesis technique of {gamma}-AlON in NH{sub 3} plasma using extended arc thermal plasma reactor have been reported. Dense cubic AlON spinel was synthesized in liquid state by fusion of mixture of Al{sub 2}O{sub 3} and AlN powder under thermal plasma. The density of the fused AlON was found to be 3.64 g/cc which is 98.11% of theoretical value. The formation of AlON was confirmed from XRD and Raman studies. Well faceted structure of plasma fused AlON was observed in FE-SEM micrograph.

  4. Application of the thermal plasma technique in the treatment of stone surfaces

    International Nuclear Information System (INIS)

    Gonzalez A, Z.I.

    2000-01-01

    The stone materials which form part of the cultural heritage of Mexico, are degraded under the united action of water, atmospheric gases, air pollution, temperature changes and the microorganisms action; provoking on the stone: fissures, crevices, scalings, fragmentations, pulverizations, etc. Therefore, the purpose of this work is to study the possibilities to apply a protective coating on the stone surfaces, previously clean and consolidated, through the thermal plasma technique. The purpose is to analyse the physical and chemical properties of three types of stone materials: quarry, tezontle and chiluca, usually used in constructions of cultural interest such as: historical monuments, churches, sculptures, etc., before and after to be submitted to the action of thermal plasma in order to examine the feasibility in the use of this coating technique in this type of applications. The application of conventional techniques to determine: porosity, density, absorption, low pressure water absorption and crystallization by total immersion of nuclear techniques such as: neutron activation analysis, x-ray diffraction and scanning electron microscopy as well as of instrumental techniques: optical microscopy, mechanical assays of compression, flexure and surface area calculations, allowed to know the chemical and physical properties of the stone material before and after to be treated through the thermal plasma technique, projecting quartz on the stones surface at different distances and current intensity and showing the effect caused by the modifications or surface alterations present by cause of the application of that coating. the obtained results provide a general panorama of the application of this technique as an alternative to the maintenance of the architectural inheritance built in stone. (Author)

  5. Supplier Selection in the Thermal Tourism Enterprises with Using Multi Criteria Decision Making Techniques

    Directory of Open Access Journals (Sweden)

    Hatice Gündüz

    2015-06-01

    Full Text Available Turkey has many natural health resources and the interest in Thermal Tourism has increased. Thermal Tourism Enterprises serve their experienced medical staff, treatment methods and the curative springs for the purpose of care services. On the other hand, these enterprises are also the place to have both a rest and a good time. In this study, the supplier selection application is performed in the Thermal Tourism Enterprise that offers a combination of services as health, recreation and entertainment. The criteria as product quality and performance, product information, product arrival time, price, quality practices, flexibility and the collaboration level have been considered. By using multi-criteria decision making techniques as Analytic Hierarchy Process (AHP and TOPSIS then the suggestions on the selecting the best supplier are offered.

  6. Research technique and experimental device for thermal conductivity measurements of refractory compounds

    International Nuclear Information System (INIS)

    Vishnevetskaya, I.A.; Petrov, V.A.

    1977-01-01

    Proposed is a new axial technique for determining thermal conductivity coefficient of solids at temperatures above 1000 deg C with the use of internal heating of specimens by passing electric current and with experimental determining the thermal flows on the lateral side of the working section of the specimen. This method is usable for investigating the thermal conductivity of materials whose surface radiation characteristics are unknown or unstable and for carrying out experiments not only in vacuum, but also in various atmospheres. The overall fiducial error of the results of the method is evaluated at 4-5 % within the range of temperatures between 1200 and 2300 K. A description of the experimental installation is given

  7. An extended laser flash technique for thermal diffusivity measurement of high-temperature materials

    Science.gov (United States)

    Shen, F.; Khodadadi, J. M.

    1993-01-01

    Knowledge of thermal diffusivity data for high-temperature materials (solids and liquids) is very important in analyzing a number of processes, among them solidification, crystal growth, and welding. However, reliable thermal diffusivity versus temperature data, particularly those for high-temperature liquids, are still far from complete. The main measurement difficulties are due to the presence of convection and the requirement for a container. Fortunately, the availability of levitation techniques has made it possible to solve the containment problem. Based on the feasibility of the levitation technology, a new laser flash technique which is applicable to both levitated liquid and solid samples is being developed. At this point, the analysis for solid samples is near completion and highlights of the technique are presented here. The levitated solid sample which is assumed to be a sphere is subjected to a very short burst of high power radiant energy. The temperature of the irradiated surface area is elevated and a transient heat transfer process takes place within the sample. This containerless process is a two-dimensional unsteady heat conduction problem. Due to the nonlinearity of the radiative plus convective boundary condition, an analytic solution cannot be obtained. Two options are available at this point. Firstly, the radiation boundary condition can be linearized, which then accommodates a closed-form analytic solution. Comparison of the analytic curves for the temperature rise at different points to the experimentally-measured values will then provide the thermal diffusivity values. Secondly, one may set up an inverse conduction problem whereby experimentally obtained surface temperature history is used as the boundary conditions. The thermal diffusivity can then be elevated by minimizing the difference between the real heat flux boundary condition (radiation plus convection) and the measurements. Status of an experimental study directed at measuring the

  8. Thermal conductivity of organic semi-conducting materials using 3omega and photothermal radiometry techniques

    Directory of Open Access Journals (Sweden)

    Reisdorffer Frederic

    2014-01-01

    Full Text Available Organic semiconductors for opto-electronic devices show several defects which can be enhanced while increasing the operating temperature. Their thermal management and especially the reduction of their temperature are of great interest. For the heat transfer study, one has to measure the thermal conductivity of thin film organic materials. However the major difficulty for this measurement is the very low thickness of the films which needs the use of very specific techniques. In our work, the 3-omega and photothermal radiometric methods were used to measure the thermal conductivity of thin film organic semiconducting material (Alq3. The measurements were performed as function of the thin film thickness from 45 to 785 nm and also of its temperature from 80 to 350 K. With the 3 omega method, a thermal conductivity value of 0.066 W.m−1K−1 was obtained for Alq3 thin film of 200 nm at room temperature, in close agreement with the photothermal value. Both techniques appear to be complementary: the 3 omega method is easier to implement for large temperature range and small thicknesses down to a few tens of nanometers whereas the photothermal method is more suitable for thicknesses over 200nm since it provides additional information such as the thin film volumetric heat capacity.

  9. Monitoring volcanic thermal activity by Robust Satellite Techniques: achievements and perspectives

    Science.gov (United States)

    Tramutoli, V.; Marchese, F.; Mazzeo, G.; Pergola, N.

    2009-12-01

    Satellite data have been increasingly used in last decades to study active volcanoes and to monitor thermal activity variation in space-time domain. Several satellite techniques and original methods have been developed and tested, devoted to hotspot detection and thermal monitoring. Among them, a multi-temporal approach, named RST (Robust Satellite Techniques), has shown high performances in detecting hotspots, with a low false positive rate under different observational and atmospheric conditions, providing also a potential toward low-level thermal anomalies which may announce incoming eruptions. As the RST scheme is intrinsically exportable on different geographic areas and satellite sensors, it has been applied and tested on a number of volcanoes and in different environmental conditions. This work presents major results and outcomes of studies carried out on Etna and Stromboli (Italy), Merapi (Java Indonesia), Asamayama (Japan), Jebel Al Tair (Yemen) by using different satellite systems and sensors (e.g. NOAA-AVHRR, EOS-MODIS, MSG-SEVIRI). Performances on hotspot detection, early warning and real-time monitoring, together with capabilities in possible thermal precursor identification, will be presented and discussed.

  10. Spontaneous high piezoelectricity in poly(vinylidene fluoride) nanoribbons produced by iterative thermal size reduction technique.

    Science.gov (United States)

    Kanik, Mehmet; Aktas, Ozan; Sen, Huseyin Sener; Durgun, Engin; Bayindir, Mehmet

    2014-09-23

    We produced kilometer-long, endlessly parallel, spontaneously piezoelectric and thermally stable poly(vinylidene fluoride) (PVDF) micro- and nanoribbons using iterative size reduction technique based on thermal fiber drawing. Because of high stress and temperature used in thermal drawing process, we obtained spontaneously polar γ phase PVDF micro- and nanoribbons without electrical poling process. On the basis of X-ray diffraction (XRD) analysis, we observed that PVDF micro- and nanoribbons are thermally stable and conserve the polar γ phase even after being exposed to heat treatment above the melting point of PVDF. Phase transition mechanism is investigated and explained using ab initio calculations. We measured an average effective piezoelectric constant as -58.5 pm/V from a single PVDF nanoribbon using a piezo evaluation system along with an atomic force microscope. PVDF nanoribbons are promising structures for constructing devices such as highly efficient energy generators, large area pressure sensors, artificial muscle and skin, due to the unique geometry and extended lengths, high polar phase content, high thermal stability and high piezoelectric coefficient. We demonstrated two proof of principle devices for energy harvesting and sensing applications with a 60 V open circuit peak voltage and 10 μA peak short-circuit current output.

  11. Simultaneous Absorptance and Thermal-Diffusivity Determination of Optical Components with Laser Calorimetry Technique

    Science.gov (United States)

    Wang, Yanru; Li, Bincheng

    2012-11-01

    The laser calorimetry (LCA) technique is used to determine simultaneously the absorptances and thermal diffusivities of optical components. An accurate temperature model, in which both the finite thermal conductivity and the finite sample size are taken into account, is employed to fit the experimental temperature data measured with an LCA apparatus for a precise determination of the absorptance and thermal diffusivity via a multiparameter fitting procedure. The uniqueness issue of the multiparameter fitting is discussed in detail. Experimentally, highly reflective (HR) samples prepared with electron-beam evaporation on different substrates (BK7, fused silica, and Ge) are measured with LCA. For the HR-coated sample on a fused silica substrate, the absorptance is determined to be 15.4 ppm, which is close to the value of 17.6 ppm, determined with a simplified temperature model recommended in the international standard ISO11551. The thermal diffusivity is simultaneously determined via multiparameter fitting to be approximately 6.63 × 10-7 m2 · s-1 with a corresponding square variance of 4.8 × 10-4. The fitted thermal diffusivity is in reasonably good agreement with the literature value (7.5 × 10-7 m2 · s -1). Good agreement is also obtained for samples with BK7 and Ge substrates.

  12. Experimental study on thermal hazard of tributyl phosphate-nitric acid mixtures using micro calorimeter technique

    Energy Technology Data Exchange (ETDEWEB)

    Sun, Qi; Jiang, Lin; Gong, Liang; Sun, Jin-Hua, E-mail: sunjh@ustc.edu.cn

    2016-08-15

    Highlights: • Heat flows after mixing TBP with nitric acid are of different orders of magnitude. • Thermodynamics and kinetics of tributyl phosphate-nitric acid mixtures are derived. • Tributyl phosphate directly reacts with nitric acid and form organic red oil. • Thermal runaway could occur at 79 °C with a high nitric acid concentration. - Abstract: During PUREX spent nuclear fuel reprocessing, mixture of tributyl phosphate (TBP) and hydrocarbon solvent are employed as organic solvent to extract uranium in consideration of radiation contaminated safety and resource recycling, meanwhile nitric acid is utilized to dissolve the spent fuel into small pieces. However, once TBP contacts with nitric acid or nitrates above 130 °C, a heavy “red oil” layer would occur accompanied by thermal runaway reactions, even caused several nuclear safety accident. Considering nitric acid volatility and weak exothermic detection, C80 micro calorimeter technique was used in this study to investigate thermal decomposition of TBP mixed with nitric acid. Results show that the concentration of nitric acid greatly influences thermal hazard of the system by direct reactions. Even with a low heating rate, if the concentration of nitric acid increases due to evaporation of water or improper operations, thermal runaway in the closed system could start at a low temperature.

  13. Transport and calorimetric properties of AISI 321 by pulse thermal diffusivity and calorimetric techniques

    International Nuclear Information System (INIS)

    Perovic, N.L.; Maglic, K.D.; Stanimirovic, A.M.; Vukovic, G.S.

    1995-01-01

    The study of the thermophysical properties of AISI 321 stainless steel was the last part of work within the IAEA-coordinated Research Programme for the Establishment of a Database of Thermophysical Properties of LW and HW Reactor Materials (IAEA CRP) effected at the Institute of Nuclear Sciences Vinca (NIV). The AISI 321 stainless steel belongs to the group of construction materials whose thermophysical and calorimetric properties have significance for the IAEA CRP. Because there have been few investigations of the thermal properties of this material, the CRP foresaw the need for new measurements, which are reported in this paper. Experimental research performed at NIV consisted of the investigation of thermal diffusivity, electric resistivity, and specific heat capacity of this austenitic stainless steel. The thermal diffusivity was measured by the laser pulse technique, and the elastic resistivity and specific heat capacity were determined by use of millisecond-resolution pulse calorimetry. All measurements were performed from ambient temperature to above 1000 o C, within which temperature range the material maintains its structure and stable thermophysical properties. Values for the thermal conductivity were computed from data on the thermal diffusivity, specific heat capacity, and the room-temperature density. (author)

  14. Development of a Nondestructive Evaluation Technique for Degraded Thermal Barrier Coatings Using Microwave

    Science.gov (United States)

    Sayar, M.; Ogawa, K.; Shoji, T.

    2008-02-01

    Thermal barrier coatings have been widely used in gas turbine engines in order to protect substrate metal alloy against high temperature and to enhance turbine efficiency. Currently, there are no reliable nondestructive techniques available to monitor TBC integrity over lifetime of the coating. Hence, to detect top coating (TC) and TGO thicknesses, a microwave nondestructive technique that utilizes a rectangular waveguide was developed. The phase of the reflection coefficient at the interface of TC and waveguide varies for different TGO and TC thicknesses. Therefore, measuring the phase of the reflection coefficient enables us to accurately calculate these thicknesses. Finally, a theoretical analysis was used to evaluate the reliability of the experimental results.

  15. Estimation of fracture parameters in foam core materials using thermal techniques

    DEFF Research Database (Denmark)

    Dulieu-Barton, J. M.; Berggreen, Christian; Boyenval Langlois, C.

    2010-01-01

    is described. A mode I simulated crack in the form of a machined notch is used to establish the feasibility of the TSA approach to derive stress intensity factors for the foam material. The overall goal is to demonstrate that thermal techniques have the ability to provide deeper insight into the behaviour......The paper presents some initial work on establishing the stress state at a crack tip in PVC foam material using a non-contact infra-red technique known as thermoelastic stress analysis (TSA). A parametric study of the factors that may affect the thermoelastic response of the foam material...

  16. Separation Techniques for Uranium and Plutonium at Trace Levels for the Thermal Ionization Mass Spectrometric Determination

    International Nuclear Information System (INIS)

    Suh, M. Y.; Han, S. H.; Kim, J. G.; Park, Y. J.; Kim, W. H.

    2005-12-01

    This report describes the state of the art and the progress of the chemical separation and purification techniques required for the thermal ionization mass spectrometric determination of uranium and plutonium in environmental samples at trace or ultratrace levels. Various techniques, such as precipitation, solvent extraction, extraction chromatography, and ion exchange chromatography, for separation of uranium and plutonium were evaluated. Sample preparation methods and dissolution techniques for environmental samples were also discussed. Especially, both extraction chromatographic and anion exchange chromatographic procedures for uranium and plutonium in environmental samples, such as soil, sediment, plant, seawater, urine, and bone ash were reviewed in detail in order to propose some suitable methods for the separation and purification of uranium and plutonium from the safeguards environmental or swipe samples. A survey of the IAEA strengthened safeguards system, the clean room facility of IAEA's NWAL(Network of Analytical Laboratories), and the analytical techniques for safeguards environmental samples was also discussed here

  17. Quality control for total evaporation technique by surface/thermal ionization mass spectrometer

    International Nuclear Information System (INIS)

    Kato, Seikou; Inoue, Sinichi; Yamaguchi, Katsuyuki; Tsutaki, Yasuhiro

    2007-01-01

    For the measurement of uranium and plutonium isotopic composition, the surface/thermal ionization mass spectrometry is widely used at the both nuclear facilities and safeguards verification laboratories. The progress of instrument specification makes higher sensitivity. The total evaporation technique is one of the latest measurement techniques by using this progress, in which all of uranium or plutonium on the filament would be evaporated by increasing the filament current. The accuracy and precision of this technique is normally checked by using the certified isotope reference materials measurement. But the fluctuation of ion beam is very different by each filament, depending on the chemical form of evaporation. So, it should be considered how to check the measurement quality of unknown samples which has no certified values. This presentation is focused on the monitoring of ion yields and pattern of isotope ratio fluctuation to attain the traceability between reference material and unknown sample as quality control approach of total evaporation technique. (author)

  18. Analysis of rocks involving the x-ray diffraction, infrared and thermal gravimetric techniques

    International Nuclear Information System (INIS)

    Ikram, M.; Rauf, M.A.; Munir, N.

    1998-01-01

    Chemical analysis of rocks and minerals are usually obtained by a number of analytical techniques. The purpose of present work is to investigate the chemical composition of the rock samples and also to find that how far the results obtained by different instrumental methods are closely related. Chemical tests wee performed before using the instrumental techniques in order to determined the nature of these rocks. The chemical analysis indicated mainly the presence of carbonate and hence the carbonate nature of these rocks. The x-ray diffraction, infrared spectroscopy and thermal gravimetric analysis techniques were used for the determination of chemical composition of these samples. The results obtained by using these techniques have shown a great deal of similarities. (author)

  19. Separation Techniques for Uranium and Plutonium at Trace Levels for the Thermal Ionization Mass Spectrometric Determination

    Energy Technology Data Exchange (ETDEWEB)

    Suh, M. Y.; Han, S. H.; Kim, J. G.; Park, Y. J.; Kim, W. H

    2005-12-15

    This report describes the state of the art and the progress of the chemical separation and purification techniques required for the thermal ionization mass spectrometric determination of uranium and plutonium in environmental samples at trace or ultratrace levels. Various techniques, such as precipitation, solvent extraction, extraction chromatography, and ion exchange chromatography, for separation of uranium and plutonium were evaluated. Sample preparation methods and dissolution techniques for environmental samples were also discussed. Especially, both extraction chromatographic and anion exchange chromatographic procedures for uranium and plutonium in environmental samples, such as soil, sediment, plant, seawater, urine, and bone ash were reviewed in detail in order to propose some suitable methods for the separation and purification of uranium and plutonium from the safeguards environmental or swipe samples. A survey of the IAEA strengthened safeguards system, the clean room facility of IAEA's NWAL(Network of Analytical Laboratories), and the analytical techniques for safeguards environmental samples was also discussed here.

  20. Improving of the photovoltaic / thermal system performance using water cooling technique

    International Nuclear Information System (INIS)

    Hussien, Hashim A; Numan, Ali H; Abdulmunem, Abdulmunem R

    2015-01-01

    This work is devoted to improving the electrical efficiency by reducing the rate of thermal energy of a photovoltaic/thermal system (PV/T).This is achieved by design cooling technique which consists of a heat exchanger and water circulating pipes placed at PV module rear surface to solve the problem of the high heat stored inside the PV cells during the operation. An experimental rig is designed to investigate and evaluate PV module performance with the proposed cooling technique. This cooling technique is the first work in Iraq to dissipate the heat from PV module. The experimental results indicated that due to the heat loss by convection between water and the PV panel's upper surface, an increase of output power is achieved. It was found that without active cooling, the temperature of the PV module was high and solar cells could only achieve a conversion efficiency of about 8%. However, when the PV module was operated under active water cooling condition, the temperature was dropped from 76.8°C without cooling to 70.1°C with active cooling. This temperature dropping led to increase in the electrical efficiency of solar panel to 9.8% at optimum mass flow rate (0.2L/s) and thermal efficiency to (12.3%). (paper)

  1. A Noncontact Measurement Technique for the Density and Thermal Expansion Coefficient of Solid and Liquid Materials

    Science.gov (United States)

    Chung, Sang K.; Thiessen, David B.; Rhim, Won-Kyu

    1996-01-01

    A noncontact measurement technique for the density and the thermal expansion refractory materials in their molten as well as solid phases is presented. This technique is based on the video image processing of a levitated sample. Experiments were performed using the high-temperature electrostatic levitator (HTESL) at the Jet Propulsion Laboratory in which 2-3 mm diameter samples can be levitated, melted, and radiatively cooled in a vacuum. Due to the axisymmetric nature of the molten samples when levitated in the HTESL, a rather simple digital image analysis can be employed to accurately measure the volumetric change as a function of temperature. Density and the thermal expansion coefficient measurements were made on a pure nickel sample to test the accuracy of the technique in the temperature range of 1045-1565 C. The result for the liquid phase density can be expressed by p = 8.848 + (6.730 x 10(exp -4)) x T (degC) g/cu cm within 0.8% accuracy, and the corresponding thermal expansion coefficient can be expressed by Beta=(9.419 x 10(exp -5)) - (7.165 x 10(exp -9) x T (degC)/K within 0.2% accuracy.

  2. A parylene-filled-trench technique for thermal isolation in silicon-based microdevices

    International Nuclear Information System (INIS)

    Lei Yinhua; Wang Wei; Li Ting; Jin Yufeng; Zhang Haixia; Li Zhihong; Yu Huaiqiang; Luo Yingcun

    2009-01-01

    Microdevices prepared in a silicon substrate have been widely used in versatile fields due to the matured silicon-based microfabrication technique and the excellent physical properties of silicon material. However, the high thermal conductivity of silicon restricts its application in most thermal microdevices, especially devices comprising different temperature zones. In this work, a parylene-filled-trench technique was optimized to realize high-quality thermal isolation in silicon-based microdevices. Parylene C, a heat transfer barricading material, was deposited on parallel high-aspect-ratio trenches, which surrounded the isolated target zones. After removing the remnant silicon beneath the trenches by deep reactive ion etching from the back side, a high-quality heat transfer barrier was obtained. By using narrow trenches, only 5 µm thick parylene was required for a complete filling, which facilitated multi-layer interconnection thereafter. The parylene filling performance inside the high-aspect-ratio trench was optimized by two approaches: multiple etch–deposition cycling and trench profile controlling. A 4 × 6 array, in which each unit was kept at a constant temperature and was well thermally isolated individually, was achieved on a silicon substrate by using the present parylene-filled-trench technique. The preliminary experimental results indicated that the present parylene-filled-trench structure exhibited excellent thermal isolation performance, with a very low power requirement of 0.134 mW (K mm 2 ) −1 for heating the isolated silicon unit and a high thermal isolation efficiency of 72.5% between two adjacent units. Accompanied with high-quality isolation performance, the microdevices embedded the present parylene-filled-trench structure to retain a strong mechanical connection larger than 400 kPa between two isolated zones, which is very important for a high-reliability-required micro-electro-mechanical-system (MEMS) device. Considering its room

  3. Converging or Diverging Lens?

    Science.gov (United States)

    Branca, Mario

    2013-01-01

    Why does a lens magnify? Why does it shrink objects? Why does this happen? The activities that we propose here are useful in helping us to understand how lenses work, and they show that the same lens can have different magnification capabilities. A converging lens can also act as a diverging lens. (Contains 4 figures.)

  4. Development of a novel mixed hemimicelles dispersive micro solid phase extraction using 1-hexadecyl-3-methylimidazolium bromide coated magnetic graphene for the separation and preconcentration of fluoxetine in different matrices before its determination by fiber optic linear array spectrophotometry and mode-mismatched thermal lens spectroscopy

    International Nuclear Information System (INIS)

    Kazemi, Elahe; Haji Shabani, Ali Mohammad; Dadfarnia, Shayessteh; Abbasi, Amir; Rashidian Vaziri, Mohammad Reza; Behjat, Abbas

    2016-01-01

    This study aims at developing a novel, sensitive, fast, simple and convenient method for separation and preconcentration of trace amounts of fluoxetine before its spectrophotometric determination. The method is based on combination of magnetic mixed hemimicelles solid phase extraction and dispersive micro solid phase extraction using 1-hexadecyl-3-methylimidazolium bromide coated magnetic graphene as a sorbent. The magnetic graphene was synthesized by a simple coprecipitation method and characterized by X-ray diffraction (XRD), Fourier transform infrared (FT-IR) spectroscopy and scanning electron microscopy (SEM). The retained analyte was eluted using a 100 μL mixture of methanol/acetic acid (9:1) and converted into fluoxetine-β-cyclodextrin inclusion complex. The analyte was then quantified by fiber optic linear array spectrophotometry as well as mode-mismatched thermal lens spectroscopy (TLS). The factors affecting the separation, preconcentration and determination of fluoxetine were investigated and optimized. With a 50 mL sample and under optimized conditions using the spectrophotometry technique, the method exhibited a linear dynamic range of 0.4–60.0 μg L"−"1, a detection limit of 0.21 μg L"−"1, an enrichment factor of 167, and a relative standard deviation of 2.1% and 3.8% (n = 6) at 60 μg L"−"1 level of fluoxetine for intra- and inter-day analyses, respectively. However, with thermal lens spectrometry and a sample volume of 10 mL, the method exhibited a linear dynamic range of 0.05–300 μg L"−"1, a detection limit of 0.016 μg L"−"1 and a relative standard deviation of 3.8% and 5.6% (n = 6) at 60 μg L"−"1 level of fluoxetine for intra- and inter-day analyses, respectively. The method was successfully applied to determine fluoxetine in pharmaceutical formulation, human urine and environmental water samples. - Graphical abstract: A novel, sensitive, fast, simple and convenient mixed hemimicelles dispersive micro solid

  5. Development of a novel mixed hemimicelles dispersive micro solid phase extraction using 1-hexadecyl-3-methylimidazolium bromide coated magnetic graphene for the separation and preconcentration of fluoxetine in different matrices before its determination by fiber optic linear array spectrophotometry and mode-mismatched thermal lens spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Kazemi, Elahe; Haji Shabani, Ali Mohammad [Department of Chemistry, Yazd University, Safaieh, 89195-741, Yazd (Iran, Islamic Republic of); Dadfarnia, Shayessteh, E-mail: sdadfarnia@yazd.ac.ir [Department of Chemistry, Yazd University, Safaieh, 89195-741, Yazd (Iran, Islamic Republic of); Abbasi, Amir [Department of Physics, Yazd University, Safaieh, 89195-741, Yazd (Iran, Islamic Republic of); Rashidian Vaziri, Mohammad Reza [Laser and Optics Research School, 14155-1339, Tehran (Iran, Islamic Republic of); Behjat, Abbas [Department of Physics, Yazd University, Safaieh, 89195-741, Yazd (Iran, Islamic Republic of)

    2016-01-28

    This study aims at developing a novel, sensitive, fast, simple and convenient method for separation and preconcentration of trace amounts of fluoxetine before its spectrophotometric determination. The method is based on combination of magnetic mixed hemimicelles solid phase extraction and dispersive micro solid phase extraction using 1-hexadecyl-3-methylimidazolium bromide coated magnetic graphene as a sorbent. The magnetic graphene was synthesized by a simple coprecipitation method and characterized by X-ray diffraction (XRD), Fourier transform infrared (FT-IR) spectroscopy and scanning electron microscopy (SEM). The retained analyte was eluted using a 100 μL mixture of methanol/acetic acid (9:1) and converted into fluoxetine-β-cyclodextrin inclusion complex. The analyte was then quantified by fiber optic linear array spectrophotometry as well as mode-mismatched thermal lens spectroscopy (TLS). The factors affecting the separation, preconcentration and determination of fluoxetine were investigated and optimized. With a 50 mL sample and under optimized conditions using the spectrophotometry technique, the method exhibited a linear dynamic range of 0.4–60.0 μg L{sup −1}, a detection limit of 0.21 μg L{sup −1}, an enrichment factor of 167, and a relative standard deviation of 2.1% and 3.8% (n = 6) at 60 μg L{sup −1} level of fluoxetine for intra- and inter-day analyses, respectively. However, with thermal lens spectrometry and a sample volume of 10 mL, the method exhibited a linear dynamic range of 0.05–300 μg L{sup −1}, a detection limit of 0.016 μg L{sup −1} and a relative standard deviation of 3.8% and 5.6% (n = 6) at 60 μg L{sup −1} level of fluoxetine for intra- and inter-day analyses, respectively. The method was successfully applied to determine fluoxetine in pharmaceutical formulation, human urine and environmental water samples. - Graphical abstract: A novel, sensitive, fast, simple and convenient mixed hemimicelles

  6. Detection of Certain Spices Subjected to Gamma Irradiation By Using Thermal Analysis Technique

    International Nuclear Information System (INIS)

    Sayed, M.S.; Ali, H.G.M.; Abdeldaiem, M.H.

    2013-01-01

    The present investigation was carried out to apply a detection method of some irradiated spices using thermal analysis technique. Black pepper, cumin and ginger were irradiated using gamma irradiation at dose levels 5, 10 and 15 kGy and stored for 12 months at room temperature. Thermal analysis techniques TGA and DTA were studied for characterizing irradiated spices. Thermo gravimetric analysis (TGA) is a method where the measurement of mass as a function of heating is recorded. TGA was used to determine the moisture and ash contents and thermal stabilities. Non-significant changes of the weight loss percent due to the irradiation were occurred on the studied spices up to 10 kGy. The weight loss was decreased at the first step up to 100 degree C due to the release of water of hydration. Another sharp decreasing in weight loss percent at the second step 220-300 degree C may be due to volatilization of the sample. The final weight loss weight loss stage up to 500 degree C may be due to burn out the fixed carbon remaining in the sample. As the irradiation dose increased from control up to 15 kGy, the weight loss percent at the dehydration step was decreased. The kinetics of the spices decomposition were studied in order to ascertain the type of weight loss mechanism and calculate the activation energy (E a ). The differential thermal analysis (DTA) of the studied samples showed two main characteristic peaks; endothermic one due to the dehydration process and the second peak may be due to the partial volatilization of the aromatic compounds of the main constituent of the studied spices. It could be concluded that using gamma irradiation (up to 15.0 kGy) for black pepper, cumin and ginger are thermally stable to human consumption.

  7. Mathematical Foundation Based Inter-Connectivity modelling of Thermal Image processing technique for Fire Protection

    Directory of Open Access Journals (Sweden)

    Sayantan Nath

    2015-09-01

    Full Text Available In this paper, integration between multiple functions of image processing and its statistical parameters for intelligent alarming series based fire detection system is presented. The proper inter-connectivity mapping between processing elements of imagery based on classification factor for temperature monitoring and multilevel intelligent alarm sequence is introduced by abstractive canonical approach. The flow of image processing components between core implementation of intelligent alarming system with temperature wise area segmentation as well as boundary detection technique is not yet fully explored in the present era of thermal imaging. In the light of analytical perspective of convolutive functionalism in thermal imaging, the abstract algebra based inter-mapping model between event-calculus supported DAGSVM classification for step-by-step generation of alarm series with gradual monitoring technique and segmentation of regions with its affected boundaries in thermographic image of coal with respect to temperature distinctions is discussed. The connectedness of the multifunctional operations of image processing based compatible fire protection system with proper monitoring sequence is presently investigated here. The mathematical models representing the relation between the temperature affected areas and its boundary in the obtained thermal image defined in partial derivative fashion is the core contribution of this study. The thermal image of coal sample is obtained in real-life scenario by self-assembled thermographic camera in this study. The amalgamation between area segmentation, boundary detection and alarm series are described in abstract algebra. The principal objective of this paper is to understand the dependency pattern and the principles of working of image processing components and structure an inter-connected modelling technique also for those components with the help of mathematical foundation.

  8. A new technique for precise measurement of thermal conductivity of metals at normal and high temperatures

    International Nuclear Information System (INIS)

    Binkele, L.

    1990-09-01

    Theoretical and experimental investigations on a new measuring technique are described; a technique similar to the well known Kohlrausch measuring technique, which is characterized by direct electrical sample heating. Subject of the investigations is a cylindrical metallic sample, 5 mm thick and 200 mm in length, which is positioned vertically between water-cooled clamps in a vacuum container. The sample can be heated using two simultaneously operating current sources, a 50 Hz-source for axial flow (main heating) as well as a 200 kHz-induction source for generating eddy currents in two short regions above and below the sample centre (additional heating). By using two heating sources different symmetrical temperature profiles in a central eddy-current-free area of about ± 10mm can be produced for any given central sample temperature. The last chapter contains thermal conductivity and electrical resistivity measuring curves for Pt, W, Fe, Ni, Ag, Al, Mg, Ir, Ru, Re, Ho and Y in the temperature range 273 to 1500 K representative of all the metals and alloys investigated. In cases where comparisons with published precise conductivity data, established by other measuring techniques in restricted temperature ranges, were posible, the new measuring method is greatly supported (in the case of Pt, W, Ni, Ag, Al). For the Metals Ir, Ru, Re, Ho and Y high temperature thermal conductivity data are given for the first time. (orig./MM) [de

  9. Application of Microextraction Techniques Including SPME and MESI to the Thermal Degradation of Polymers: A Review.

    Science.gov (United States)

    Kaykhaii, Massoud; Linford, Matthew R

    2017-03-04

    Here, we discuss the newly developed micro and solventless sample preparation techniques SPME (Solid Phase Microextraction) and MESI (Membrane Extraction with a Sorbent Interface) as applied to the qualitative and quantitative analysis of thermal oxidative degradation products of polymers and their stabilizers. The coupling of these systems to analytical instruments is also described. Our comprehensive literature search revealed that there is no previously published review article on this topic. It is shown that these extraction techniques are valuable sample preparation tools for identifying complex series of degradation products in polymers. In general, the number of products identified by traditional headspace (HS-GC-MS) is much lower than with SPME-GC-MS. MESI is particularly well suited for the detection of non-polar compounds, therefore number of products identified by this technique is not also to the same degree of SPME. Its main advantage, however, is its ability of (semi-) continuous monitoring, but it is more expensive and not yet commercialized.

  10. Metallographic techniques for evaluation of Thermal Barrier Coatings produced by Electron Beam Physical Vapor Deposition

    International Nuclear Information System (INIS)

    Kelly, Matthew; Singh, Jogender; Todd, Judith; Copley, Steven; Wolfe, Douglas

    2008-01-01

    Thermal Barrier Coatings (TBC) produced by Electron Beam Physical Vapor Deposition (EB-PVD) are primarily applied to critical hot section turbine components. EB-PVD TBC for turbine applications exhibit a complicated structure of porous ceramic columns separated by voids that offers mechanical compliance. Currently there are no standard evaluation methods for evaluating EB-PVD TBC structure quantitatively. This paper proposes a metallographic method for preparing samples and evaluating techniques to quantitatively measure structure. TBC samples were produced and evaluated with the proposed metallographic technique and digital image analysis for columnar grain size and relative intercolumnar porosity. Incorporation of the proposed evaluation technique will increase knowledge of the relation between processing parameters and material properties by incorporating a structural link. Application of this evaluation method will directly benefit areas of quality control, microstructural model development, and reduced development time for process scaling

  11. Search method optimization technique for thermal design of high power RFQ structure

    International Nuclear Information System (INIS)

    Sharma, N.K.; Joshi, S.C.

    2009-01-01

    RRCAT has taken up the development of 3 MeV RFQ structure for the low energy part of 100 MeV H - ion injector linac. RFQ is a precision machined resonating structure designed for high rf duty factor. RFQ structural stability during high rf power operation is an important design issue. The thermal analysis of RFQ has been performed using ANSYS finite element analysis software and optimization of various parameters is attempted using Search Method optimization technique. It is an effective optimization technique for the systems governed by a large number of independent variables. The method involves examining a number of combinations of values of independent variables and drawing conclusions from the magnitude of the objective function at these combinations. In these methods there is a continuous improvement in the objective function throughout the course of the search and hence these methods are very efficient. The method has been employed in optimization of various parameters (called independent variables) of RFQ like cooling water flow rate, cooling water inlet temperatures, cavity thickness etc. involved in RFQ thermal design. The temperature rise within RFQ structure is the objective function during the thermal design. Using ANSYS Programming Development Language (APDL), various multiple iterative programmes are written and the analysis are performed to minimize the objective function. The dependency of the objective function on various independent variables is established and the optimum values of the parameters are evaluated. The results of the analysis are presented in the paper. (author)

  12. Investigation of the Promotion of Wind Power Consumption Using the Thermal-Electric Decoupling Techniques

    Directory of Open Access Journals (Sweden)

    Shuang Rong

    2015-08-01

    Full Text Available In the provinces of north China, combined heat and electric power generations (CHP are widely utilized to provide both heating source and electricity. While, due to the constraint of thermal-electric coupling within CHP, a mass of wind turbines have to offline operate during heating season to maintain the power grid stability. This paper proposes a thermal-electric decoupling (TED approach to release the energy waste. Within the thermal-electric decoupling system, heat storage and electric boiler/heat pump are introduced to provide an auxiliary thermal source during hard peak shaving period, thus relying on the participation of an outside heat source, the artificial electric power output change interval could be widened to adopt more wind power and reduce wind power curtailment. Both mathematic models and methods are proposed to calculate the evaluation indexes to weight the effect of TED, by using the Monte Carlo simulation technique. Numerical simulations have been conducted to demonstrate the effectiveness of the proposed methods, and the results show that the proposed approach could relieve up to approximately 90% of wind power curtailment and the ability of power system to accommodate wind power could be promoted about 32%; moreover, the heating source is extended, about 300 GJ heat could be supplied by TED during the whole heating season, which accounts for about 18% of the total heat need.

  13. The development of monitoring techniques for thermal stratification in nuclear plant piping

    International Nuclear Information System (INIS)

    Sim, Cheul Muu; Joo, Young Sang; Yoon, Kwang Sik; Park, Chi Seung; Choi, Ha Lim; Moon, Jae Wha; Bae, Sang Ho.

    1996-12-01

    The conventional nondestructive testing has been performed in those area which are susceptible to thermal stress in according to NRC 88-08,11. In addition to that, it is necessary to set up a monitoring system to prevent severe thermal stress to pipes in early stages and to develop the non-intrusive techniques to diagnose the check valve because the thermal stratification has been caused by the malfunction of the check valve in ECCS pipe. Thermal stratification monitoring system has been designed and installed at ECCS line permanently and surge line temporally in YG nuclear power plant. The data is acceptable in according to TASCS guide line. Also, the data originated from ISMS is useful for the arrangement of a special UT program and stress analysis. Applying a togetherness of acoustics and magnetics signal, it is possible to determine the parameters of the function of the check valve internals without disassembling it. This series of tests show that the accelerometers can be use d to measure and to differentiate the three types of impacts; metal to metal impacts mechanical rubs, and worn internal parts. The magnet sensors can be used to detect the opening/closing of stainless check and fluttering of disk. (author). 50 refs., 5 tabs., 28 figs

  14. The development of monitoring techniques for thermal stratification in nuclear plant piping

    Energy Technology Data Exchange (ETDEWEB)

    Sim, Cheul Muu; Joo, Young Sang; Yoon, Kwang Sik; Park, Chi Seung; Choi, Ha Lim; Moon, Jae Wha; Bae, Sang Ho

    1996-12-01

    The conventional nondestructive testing has been performed in those area which are susceptible to thermal stress in according to NRC 88-08,11. In addition to that, it is necessary to set up a monitoring system to prevent severe thermal stress to pipes in early stages and to develop the non-intrusive techniques to diagnose the check valve because the thermal stratification has been caused by the malfunction of the check valve in ECCS pipe. Thermal stratification monitoring system has been designed and installed at ECCS line permanently and surge line temporally in YG nuclear power plant. The data is acceptable in according to TASCS guide line. Also, the data originated from ISMS is useful for the arrangement of a special UT program and stress analysis. Applying a togetherness of acoustics and magnetics signal, it is possible to determine the parameters of the function of the check valve internals without disassembling it. This series of tests show that the accelerometers can be use d to measure and to differentiate the three types of impacts; metal to metal impacts mechanical rubs, and worn internal parts. The magnet sensors can be used to detect the opening/closing of stainless check and fluttering of disk. (author). 50 refs., 5 tabs., 28 figs.

  15. Certification of temperature measuring techniques at thermal and nuclear power plants

    International Nuclear Information System (INIS)

    Preobrazhenskij, V.P.; Strigina, L.A.

    1980-01-01

    Necessity for metrological certification of temperature measurement techniques (TMT) at thermal and nuclear energy plants is grounded. An order of TMT certification is stated and formulae for determining the accuracy of temperature measurements by the thermoelectric method are given. It is concluded that through there are also statistical characteristics of errors of a number of measurement properties, it is necessary to carry on statistical investigations into errors of thermoelectrode extending wires, planimeters, measurement conditions. Such kind investigation technigues have been developed. Besides, it is necessary to regulate a uniform approach to the usage of statistical characteristics of errors of means and conditions of measurements to minimize volume of work for the personnel of thermal and nuclear energy plants and provide reliable estimates of temperature measurement errors

  16. Microstructure and thermal properties of Cu-SiC composite materials depending on the sintering technique

    Directory of Open Access Journals (Sweden)

    Chmielewski Marcin

    2017-01-01

    Full Text Available The presented paper investigates the relationship between the microstructure and thermal properties of copper-silicon carbide composites obtained through hot pressing (HP and spark plasma sintering (SPS techniques. The microstructural analysis showed a better densification in the case of composites sintered in the SPS process. TEM investigations revealed the presence of silicon in the area of metallic matrix in the region close to metal-ceramic boundary. It is the product of silicon dissolving process in copper occurring at an elevated temperature. The Cu-SiC interface is significantly defected in composites obtained through the hot pressing method, which has a major influence on the thermal conductivity of materials.

  17. Thermal-hydraulic analysis techniques for axisymmetric pebble bed nuclear reactor cores

    International Nuclear Information System (INIS)

    Stroh, K.R.

    1979-03-01

    The pebble bed reactor's cylindrical core volume contains a random bed of small, spherical fuel-moderator elements. These graphite spheres, containing a central region of dispersed coated-particle fissile and fertile material, are cooled by high pressure helium flowing through the connected interstitial voids. A mathematical model and numerical solution technique have been developed which allow calculation of macroscopic values of thermal-hydraulic variables in an axisymmetric pebble bed nuclear reactor core. The computer program PEBBLE is based on a mathematical model which treats the bed macroscopically as a generating, conducting porous medium. The steady-state model uses a nonlinear Forchheimer-type relation between the coolant pressure gradient and mass flux, with newly derived coefficients for the linear and quadratic resistance terms. The remaining equations in the model make use of mass continuity, and thermal energy balances for the solid and fluid phases

  18. Discrimination techniques employing both reflective and thermal multispectral signals. [for remote sensor technology

    Science.gov (United States)

    Malila, W. A.; Crane, R. B.; Richardson, W.

    1973-01-01

    Recent improvements in remote sensor technology carry implications for data processing. Multispectral line scanners now exist that can collect data simultaneously and in registration in multiple channels at both reflective and thermal (emissive) wavelengths. Progress in dealing with two resultant recognition processing problems is discussed: (1) More channels mean higher processing costs; to combat these costs, a new and faster procedure for selecting subsets of channels has been developed. (2) Differences between thermal and reflective characteristics influence recognition processing; to illustrate the magnitude of these differences, some explanatory calculations are presented. Also introduced, is a different way to process multispectral scanner data, namely, radiation balance mapping and related procedures. Techniques and potentials are discussed and examples presented.

  19. A technique to measure the thermal diffusivity of high-Tc superconductors

    International Nuclear Information System (INIS)

    Powers, C.E.

    1991-01-01

    High T(sub c) superconducting electrical current leads and ground straps will be used in cryogenic coolers in future NASA Goddard Space Flight Center missions. These superconducting samples are long, thin leads with a typical diameter of two millimeters. A longitudinal method is developed to measure the thermal diffusivity of candidate materials for this application. This technique uses a peltier junction to supply an oscillatory heat wave into one end of a sample and will use low mass thermocouples to follow the heat wave along the sample. The thermal diffusivity is calculated using both the exponential decay of the heat wave and the phase shift to the wave. Measurements are performed in a cryostat between 10 K and room temperature

  20. Image processing techniques for thermal, x-rays and nuclear radiations

    International Nuclear Information System (INIS)

    Chadda, V.K.

    1998-01-01

    The paper describes image acquisition techniques for the non-visible range of electromagnetic spectrum especially thermal, x-rays and nuclear radiations. Thermal imaging systems are valuable tools used for applications ranging from PCB inspection, hot spot studies, fire identification, satellite imaging to defense applications. Penetrating radiations like x-rays and gamma rays are used in NDT, baggage inspection, CAT scan, cardiology, radiography, nuclear medicine etc. Neutron radiography compliments conventional x-rays and gamma radiography. For these applications, image processing and computed tomography are employed for 2-D and 3-D image interpretation respectively. The paper also covers main features of image processing systems for quantitative evaluation of gray level and binary images. (author)

  1. Precision of four otolith techniques for estimating age of white perch from a thermally altered reservoir

    Science.gov (United States)

    Snow, Richard A.; Porta, Michael J.; Long, James M.

    2018-01-01

    The White Perch Morone americana is an invasive species in many Midwestern states and is widely distributed in reservoir systems, yet little is known about the species' age structure and population dynamics. White Perch were first observed in Sooner Reservoir, a thermally altered cooling reservoir in Oklahoma, by the Oklahoma Department of Wildlife Conservation in 2006. It is unknown how thermally altered systems like Sooner Reservoir may affect the precision of White Perch age estimates. Previous studies have found that age structures from Largemouth Bass Micropterus salmoides and Bluegills Lepomis macrochirus from thermally altered reservoirs had false annuli, which increased error when estimating ages. Our objective was to quantify the precision of White Perch age estimates using four sagittal otolith preparation techniques (whole, broken, browned, and stained). Because Sooner Reservoir is thermally altered, we also wanted to identify the best month to collect a White Perch age sample based on aging precision. Ages of 569 White Perch (20–308 mm TL) were estimated using the four techniques. Age estimates from broken, stained, and browned otoliths ranged from 0 to 8 years; whole‐view otolith age estimates ranged from 0 to 7 years. The lowest mean coefficient of variation (CV) was obtained using broken otoliths, whereas the highest CV was observed using browned otoliths. July was the most precise month (lowest mean CV) for estimating age of White Perch, whereas April was the least precise month (highest mean CV). These results underscore the importance of knowing the best method to prepare otoliths for achieving the most precise age estimates and the best time of year to obtain those samples, as these factors may affect other estimates of population dynamics.

  2. Sealing of thermally-sprayed stainless steel coatings against corrosion using nickel electroplating technique

    Directory of Open Access Journals (Sweden)

    Hathaipat Koiprasert

    2007-07-01

    Full Text Available Electric arc spraying (EAS is one of the thermal spray techniques used for restoration and to providecorrosion resistance. It can be utilized to build up coatings to thicknesses of several millimeters, It is easy to use on-site. Most importantly, the cost of this technique is lower than other thermal spraying techniques thatmay be suitable for part restoration. A major disadvantage associated with the electric arc sprayed coating is its high porosity, which can be as high as 3-8% making it not appropriate for use in immersion condition. This work was carried out around the idea of using electroplating to seal off the pore of the EAS coating, with an aim to improve the corrosion resistance of the coating in immersion condition. This research compared the corrosion behavior of a stainless steel 316 electric arc sprayed coating in 2M NaOH solution at 25oC. It was found that the Ni plating used as sealant can improve the corrosion resistance of the EAS coating. Furthermore, the smoothened and plated stainless steel 316 coating has a better corrosion resistance than the plated EAS coating that was not ground to smoothen the surface before plating.

  3. Study of thermal transitions in polymers by a multifrequency modulated DSC technique

    OpenAIRE

    Fraga Rivas, Iria

    2010-01-01

    Premi extraordinari doctorat curs 2009-2010, àmbit de Ciències Differential Scanning Calorimetry (DSC) is one of the most widely used thermal analysis techniques for the study of transitions and relaxation processes in polymers and also in other materials. It measures the heat flow as a function of time and/or temperature, and determines the energy released or absorbed by a sample when it is heated (cooled) or maintained at a constant temperature. Its advantages are that it is fast a...

  4. ECTOPIC LENS EXTRACTION IN CHILDREN

    Directory of Open Access Journals (Sweden)

    Vladimir Pfeifer

    2002-12-01

    Full Text Available Background. Ectopia lentis continues to be a therapeutic challenge for ophthalmologists. It can occur as an isolated condition, after ocular trauma, in association with other ocular disorders, as part of a systemic mesodermal disease or a complication of general metabolic disorders. Minimal subluxation of the lens may cause no visual symptoms, but in more advanced cases serious optical disturbances arise. The most important is amblyopia. Surgical treatment options include iris manipulation, lens discission, aspiration, intracapsular or extracapsular extraction, and pars plana lensectomy. The choice of surgical technique remains controversial, in part because of the historically poor visual results and high rate of perioperative complications, including vitreous loss and retinal detachment.Methods. We describe a surgical technique based on the use of the Cionni endocapsular tension ring, dry irrigation aspiration of lens material, centration of the capsular bag and foldable intraocular lens implantation into the bag. With mentioned surgical technique 8 patients were operated; 4 boys and 4 girls, together 11 eyes.Results. The final BCVA after follow up period improved in 9 eyes and it remained the same as before operation in one eye. Statistical comparison of preoperative and postoperative visual acuities showed significant improvement. On the other hand there was no correlation between preoperative and postoperative visual acuity.Conclusions. This surgical procedure is an alternative approach in solving this challenging cases of ectopia lentis with good postoperative visual rehabilitation.

  5. Development and application of thermal cutting techniques during Phase 1 decommissioning of WAGR

    International Nuclear Information System (INIS)

    White, S.J.

    1992-01-01

    The Windscale Advanced Gas Cooled Reactor is the UK's lead Stage 3 Decommissioning Project. One of the main objectives of the project is to demonstrate that a nuclear reactor can be safely and effectively decommissioned to a greenfield site using existing technology. Techniques using thermal cutting processes are used widely in industry and have been successfully adapted and applied to the first phase of the dismantling project. Over 1000 operational cuts have been performed using plasma cutting technology. Oxypropane and thermic lancing technique have also been applied to the dismantling the Top Biological Shield and Top Dome of the reactor pressure vessel. This paper describes the development and application of these standard technologies to the task of decommissioning a nuclear reactor. (Author)

  6. Single lens to lens duplication: The missing link

    OpenAIRE

    Bhatt, Rupal; Jethani, Jitendra; Saluja, Praveen; Bharti, Vinay

    2008-01-01

    Congenital anomalies of the lens include a wide range from lens coloboma to primary aphakia and doubling of lens. There have been few case reports of double lens; the etiology suggested is metaplastic changes in the surface ectoderm that leads to formation of two lens vesicles and hence resulting in double lens. We report a case with bilobed lens, which raises the possibility of explaining the etiology of double lens.

  7. Manufacture of micro fluidic devices by laser welding using thermal transfer printing techniques

    Science.gov (United States)

    Klein, R.; Klein, K. F.; Tobisch, T.; Thoelken, D.; Belz, M.

    2016-03-01

    Micro-fluidic devices are widely used today in the areas of medical diagnostics and drug research, as well as for applications within the process, electronics and chemical industry. Microliters of fluids or single cell to cell interactions can be conveniently analyzed with such devices using fluorescence imaging, phase contrast microscopy or spectroscopic techniques. Typical micro-fluidic devices consist of a thermoplastic base component with chambers and channels covered by a hermetic fluid and gas tight sealed lid component. Both components are usually from the same or similar thermoplastic material. Different mechanical, adhesive or thermal joining processes can be used to assemble base component and lid. Today, laser beam welding shows the potential to become a novel manufacturing opportunity for midsize and large scale production of micro-fluidic devices resulting in excellent processing quality by localized heat input and low thermal stress to the device during processing. For laser welding, optical absorption of the resin and laser wavelength has to be matched for proper joining. This paper will focus on a new approach to prepare micro-fluidic channels in such devices using a thermal transfer printing process, where an optical absorbing layer absorbs the laser energy. Advantages of this process will be discussed in combination with laser welding of optical transparent micro-fluidic devices.

  8. USING HOT WIRE TECHNIQUE FOR MEASURING THERMAL CONDUCTIVITY OF INFUSIONS OF ORGANIC AND CONVENTIONAL COFFEE

    Directory of Open Access Journals (Sweden)

    Fernando Gordillo-Delgado

    2016-07-01

    Full Text Available The technique of hot wire, a versatile method of low cost and high accuracy for measuring the thermal conductivity of fluids through the increasing temperature of a wire that is immersed into the liquid and between its ends a potential difference is abruptly applied. Using well-known conductivity liquids: water, ethylene glycol and glycerine, the system was tested and calibrated. In this work, this procedure was used to measure the thermal conductivity of the infusion samples of organic and conventional coffee. The same roast degree of the beans was verified with a colorimeter and the preparation was made by pressing 22g of coffee powder in 110mL of water. The obtained data were subjected to Analysis of Variance (ANOVA and this confirmed that the differences in the thermophysical parameter in the two samples are significant with a confidence level of 95\\%. On this way, it was proved that the thermal conductivity value of the coffee infusion allows differentiate between organic and conventional coffee.

  9. Generalized 1D photopyroelectric technique for optical and thermal characterization of liquids

    International Nuclear Information System (INIS)

    Balderas-López, J A

    2012-01-01

    The analytical solution for the one-dimensional heat diffusion problem for a three-layer system, in the Beer–Lambert model for light absorption, is used for the implementation of a photopyroelectric (PPE) methodology for thermal and optical characterization of pigments in liquid solution, even for those ones potentially harmful to the pyroelectric sensor, taking the liquid sample's thickness as the only variable. Exponential decay of the PPE amplitude followed by a constant PPE phase for solutions at low pigment concentration, and exponential decay of the PPE amplitude but a linear decrease of the PPE phase for the concentrated ones are theoretically shown, allowing measurements of the optical absorption coefficient (at the wavelength used for the analysis) and the thermal diffusivity for the liquid sample, respectively. This PPE methodology was tested by measuring the thermal diffusivity of a concentrated solution of methylene blue in distilled water and the optical absorption coefficient, at two wavelengths (658 and 785 nm), of water solutions of copper sulfate at various concentrations. These optical parameters were used for measuring the molar absorption coefficient of this last pigment in water solution at these two wavelengths. This last optical property was also measured using a commercial spectrometer, finding very good agreement with the corresponding ones using this PPE technique. (paper)

  10. New Technique for TOC Estimation Based on Thermal Core Logging in Low-Permeable Formations (Bazhen fm.)

    Science.gov (United States)

    Popov, Evgeny; Popov, Yury; Spasennykh, Mikhail; Kozlova, Elena; Chekhonin, Evgeny; Zagranovskaya, Dzhuliya; Belenkaya, Irina; Alekseev, Aleksey

    2016-04-01

    A practical method of organic-rich intervals identifying within the low-permeable dispersive rocks based on thermal conductivity measurements along the core is presented. Non-destructive non-contact thermal core logging was performed with optical scanning technique on 4 685 full size core samples from 7 wells drilled in four low-permeable zones of the Bazhen formation (B.fm.) in the Western Siberia (Russia). The method employs continuous simultaneous measurements of rock anisotropy, volumetric heat capacity, thermal anisotropy coefficient and thermal heterogeneity factor along the cores allowing the high vertical resolution (of up to 1-2 mm). B.fm. rock matrix thermal conductivity was observed to be essentially stable within the range of 2.5-2.7 W/(m*K). However, stable matrix thermal conductivity along with the high thermal anisotropy coefficient is characteristic for B.fm. sediments due to the low rock porosity values. It is shown experimentally that thermal parameters measured relate linearly to organic richness rather than to porosity coefficient deviations. Thus, a new technique employing the transformation of the thermal conductivity profiles into continuous profiles of total organic carbon (TOC) values along the core was developed. Comparison of TOC values, estimated from the thermal conductivity values, with experimental pyrolytic TOC estimations of 665 samples from the cores using the Rock-Eval and HAWK instruments demonstrated high efficiency of the new technique for the organic rich intervals separation. The data obtained with the new technique are essential for the SR hydrocarbon generation potential, for basin and petroleum system modeling application, and estimation of hydrocarbon reserves. The method allows for the TOC richness to be accurately assessed using the thermal well logs. The research work was done with financial support of the Russian Ministry of Education and Science (unique identification number RFMEFI58114X0008).

  11. Thermal dependence of ultrasound contrast agents scattering efficiency for echographic imaging techniques

    Science.gov (United States)

    Biagioni, Angelo; Bettucci, Andrea; Passeri, Daniele; Alippi, Adriano

    2015-06-01

    Ultrasound contrast agents are used in echographic imaging techniques to enhance image contrast. In addition, they may represent an interesting solution to the problem of non-invasive temperature monitoring inside the human body, based on some thermal variations of their physical properties. Contrast agents, indeed, are inserted into blood circulation and they reach the most important organs inside the human body; consequently, any thermometric property that they may possess, could be exploited for realizing a non-invasive thermometer. They essentially are a suspension of microbubbles containing a gas enclosed in a phospholipid membrane; temperature variations induce structural modifications of the microbubble phospholipid shell, thus causing thermal dependence of contrast agent's elastic characteristics. In this paper, the acoustic scattering efficiency of a bulk suspension of of SonoVue® (Bracco SpA Milan, Italy) has been studied using a pulse-echo technique in the frequency range 1-17 MHz, as it depends upon temperatures between 25 and 65°C. Experimental data confirm that the ultrasonic attenuation coefficient of SonoVue® depends on temperature between 25 and 60°C. Chemical composition of the bubble shell seem to support the hypothesis that a phase transition in the microstructure of lipid-coated microbubbles could play a key role in explaining such effect.

  12. Contact Lens Care

    Science.gov (United States)

    ... Consumers Consumer Information by Audience For Women Contact Lens Care Share Tweet Linkedin Pin it More sharing ... www.fda.gov/medwatch Learn More about Contact Lens Care Other Tips on Contact Lenses Decorative Contact ...

  13. Plasma arc and thermal lance techniques for cutting concrete and steel

    International Nuclear Information System (INIS)

    Bargagliotti, A.; Caprile, L.; Piana, F.; Tolle, E.

    1986-01-01

    The plasma arc technique is used today in industrial practice for any metal, but mainly for cutting stainless steel, carbon steel and aluminium. In air the maximum thickness that was cut in the performed tests was 150 mm, both with ferritic and austenitic steel. Underwater the maximum thickness cut was 103 mm. The two types of torch used in the tests are those used today: the plasma-shaped electrode torch (WIPC) and the pointed electrode torch (DMC-GRUEN). Two different types of gas were compared: an argon-nitrogen mixture and an argon-hydrogen mixture. The second mixture adopted results in less dust emission. The production of dust and aerosols also depends on the cutting speed, on the kind of steel, but mainly on the environmental conditions; it is reduced up to 500 times under water. Dust and aerosols can, jeopardize the efficiency of the system; moreover, the ambient air can have high-level radiation fields. Indirect and direct protections are needed (shields, remote control, robots, etc.). Tentative procedures for dismantling two types of BWR reactor are examined. Two series of tests demonstrated the feasibility of cutting the most geometrically difficult parts of the reactor internals. The thermal lance technique is used in industrial practice mainly for dismantling large reinforced concrete structures. This technique can be applied to dismantle nuclear facilities, even though it can cause some problems due to the gases, fumes and lapilli produced. In addition, the cost of this technique seems to be generally higher than the cost of other techniques. From the analyses done, the conclusion seems that both the above techniques are feasible for dismantling a nuclear power plant (NPP). The best solution is probably to analyse the different dismantling possibilities and problems and problems of each case

  14. Optimized lens-sparing treatment of retinoblastoma with electron beams

    NARCIS (Netherlands)

    Steenbakkers, RJHM; Altschuler, MD; DAngio, GJ; Goldwein, JW; Kassaee, A

    1997-01-01

    Purpose: The ideal lens-sparing radiotherapy technique for retinoblastoma calls for 100% dose to the entire retina including the ora serrata and zero dose to the lens, Published techniques, most of which use photons, have not accomplished this ideal treatment. We describe here a technique that

  15. Seasonal differences in the subjective assessment of outdoor thermal conditions and the impact of analysis techniques on the obtained results

    Science.gov (United States)

    Kántor, Noémi; Kovács, Attila; Takács, Ágnes

    2016-11-01

    Wide research attention has been paid in the last two decades to the thermal comfort conditions of different outdoor and semi-outdoor urban spaces. Field studies were conducted in a wide range of geographical regions in order to investigate the relationship between the thermal sensation of people and thermal comfort indices. Researchers found that the original threshold values of these indices did not describe precisely the actual thermal sensation patterns of subjects, and they reported neutral temperatures that vary among nations and with time of the year. For that reason, thresholds of some objective indices were rescaled and new thermal comfort categories were defined. This research investigates the outdoor thermal perception patterns of Hungarians regarding the Physiologically Equivalent Temperature ( PET) index, based on more than 5800 questionnaires. The surveys were conducted in the city of Szeged on 78 days in spring, summer, and autumn. Various, frequently applied analysis approaches (simple descriptive technique, regression analysis, and probit models) were adopted to reveal seasonal differences in the thermal assessment of people. Thermal sensitivity and neutral temperatures were found to be significantly different, especially between summer and the two transient seasons. Challenges of international comparison are also emphasized, since the results prove that neutral temperatures obtained through different analysis techniques may be considerably different. The outcomes of this study underline the importance of the development of standard measurement and analysis methodologies in order to make future studies comprehensible, hereby facilitating the broadening of the common scientific knowledge about outdoor thermal comfort.

  16. Subpixel edge estimation with lens aberrations compensation based on the iterative image approximation for high-precision thermal expansion measurements of solids

    Science.gov (United States)

    Inochkin, F. M.; Kruglov, S. K.; Bronshtein, I. G.; Kompan, T. A.; Kondratjev, S. V.; Korenev, A. S.; Pukhov, N. F.

    2017-06-01

    A new method for precise subpixel edge estimation is presented. The principle of the method is the iterative image approximation in 2D with subpixel accuracy until the appropriate simulated is found, matching the simulated and acquired images. A numerical image model is presented consisting of three parts: an edge model, object and background brightness distribution model, lens aberrations model including diffraction. The optimal values of model parameters are determined by means of conjugate-gradient numerical optimization of a merit function corresponding to the L2 distance between acquired and simulated images. Computationally-effective procedure for the merit function calculation along with sufficient gradient approximation is described. Subpixel-accuracy image simulation is performed in a Fourier domain with theoretically unlimited precision of edge points location. The method is capable of compensating lens aberrations and obtaining the edge information with increased resolution. Experimental method verification with digital micromirror device applied to physically simulate an object with known edge geometry is shown. Experimental results for various high-temperature materials within the temperature range of 1000°C..2400°C are presented.

  17. Effective evaluation of privacy protection techniques in visible and thermal imagery

    Science.gov (United States)

    Nawaz, Tahir; Berg, Amanda; Ferryman, James; Ahlberg, Jörgen; Felsberg, Michael

    2017-09-01

    Privacy protection may be defined as replacing the original content in an image region with a (less intrusive) content having modified target appearance information to make it less recognizable by applying a privacy protection technique. Indeed, the development of privacy protection techniques also needs to be complemented with an established objective evaluation method to facilitate their assessment and comparison. Generally, existing evaluation methods rely on the use of subjective judgments or assume a specific target type in image data and use target detection and recognition accuracies to assess privacy protection. An annotation-free evaluation method that is neither subjective nor assumes a specific target type is proposed. It assesses two key aspects of privacy protection: "protection" and "utility." Protection is quantified as an appearance similarity, and utility is measured as a structural similarity between original and privacy-protected image regions. We performed an extensive experimentation using six challenging datasets (having 12 video sequences), including a new dataset (having six sequences) that contains visible and thermal imagery. The new dataset is made available online for the community. We demonstrate effectiveness of the proposed method by evaluating six image-based privacy protection techniques and also show comparisons of the proposed method over existing methods.

  18. Aberration design of zoom lens systems using thick lens modules.

    Science.gov (United States)

    Zhang, Jinkai; Chen, Xiaobo; Xi, Juntong; Wu, Zhuoqi

    2014-12-20

    A systematic approach for the aberration design of a zoom lens system using a thick lens module is presented. Each component is treated as a thick lens module at the beginning of the design. A thick lens module refers to a thick lens component with a real lens structure, like lens materials, lens curvatures, lens thicknesses, and lens interval distances. All nine third-order aberrations of a thick lens component are considered during the design. The relationship of component aberrations in different zoom positions can be approximated from the aberration shift. After minimizing the aberrations of the zoom lens system, the nine third-order aberrations of every lens component can be determined. Then the thick lens structure of every lens component can be determined after optimization according to their first-order properties and third-order aberration targets. After a third optimization for minimum practical third-order aberrations of a zoom lens system, the aberration design using the thick lens module is complete, which provides a practical zoom lens system with thick lens structures. A double-sided telecentric zoom lens system is designed using the thick lens module in this paper, which shows that this method is practical for zoom lens design.

  19. Thermal lensing measurement from the coefficient of defocus aberration

    CSIR Research Space (South Africa)

    Bell, Teboho

    2016-03-01

    Full Text Available We measured the thermally induced lens from the coefficient of defocus aberration using a Shack-Hartmann wavefront sensor (SHWFS). As a calibration technique, we infer the focal length of standard lenses probed by a collimated Gaussian beam...

  20. Techniques of thermal energy conservation; Tecnicas de conservacion de la energia termica

    Energy Technology Data Exchange (ETDEWEB)

    Caltenco Estevez, Juan Luis; Roblez Lopez, Francisco; Ceballos Serna, Andres Alberto [Instituto Mexicano del Petroleo (Mexico)

    1996-07-01

    In modern industry the thermal energy is the energy more intensely used, which implies that in the processes and equipment that operate based on it, rely the greatest opportunities for saving . In this paper some saving and conservation techniques of thermal energy, which nowadays have been developed, are presented, whose application has helped to the successful attainment of the objectives of increased productivity of industrial plants, with the additional benefit of reducing the environmental impact of the production activities. [Spanish] En la industria moderna la energia termica es la forma de energia mas intensamente utilizada, lo cual implica que en los procesos y equipos que operan basandose en esta, residan las mayores oportunidades de ahorro. En este trabajo se presentan algunas de las tecnicas de ahorro y conservacion de energia termica, que hoy en dia se han desarrollado, cuya aplicacion ha coadyuvado a la consecucion exitosa de los objetivos de incremento de la productividad de plantas industriales, con el beneficio adicional de reducir el impacto ambiental de las actividades productivas.

  1. Microstructural Improvement of Hydroxyapatite-ZrO2 Composite Ceramics via Thermal Precipitation Techniques.

    Science.gov (United States)

    Sangmala, A.; Limsuwan, P.; Kaewwiset, W.; Naemchanthara, K.

    2017-09-01

    Hydroxyapatite-ZrO2 composite ceramic were synthesized using a thermal precipitation techniques. The chemical precursors were prepared from di-ammonium hydrogen orthophosphate, calcium oxide (CaO) derived from chicken eggshell, zirconium dioxide (ZrO2) and distilled water. The mixture were heated at the various temperatures from 100 to 700 °C in the furnace with an incremental temperature of 100 °C. The ZrO2 contents in the composite ceramic were varied from 0 to 15 percent weight of CaO. The prepared composites were then annealed at 300, 600 and 700 °C for 4 h in air. The crystal structure, function group and morphology of all samples were characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), field emission scanning electron microscopy (FESEM) and universal testing machine (UTM), respectively. The results indicated that the undoped-ZrO2 samples hydroxyapatite phase with a hexagonal structure. However, the hydroxyapatite was transformed to the tri-calcium phosphate after thermal treatment at 700 °C. For the doped-ZrO2 samples, the hydroxyapatite and ZrO2 phases were found. Moreover, the result showed that the compressive strength of hydroxyapatite-ZrO2 composite ceramic increased with increasing the ZrO2 content.

  2. Thermal effusivity measurement of conventional and organic coffee oils via photopyroelectric technique.

    Science.gov (United States)

    Bedoya, A; Gordillo-Delgado, F; Cruz-Santillana, Y E; Plazas, J; Marin, E

    2017-12-01

    In this work, oil samples extracted from organic and conventional coffee beans were studied. A fatty acids profile analysis was done using gas chromatography and physicochemical analysis of density and acidity index to verify the oil purity. Additionally, Mid-Infrared Fourier Transform Photoacoustic Spectroscopy (FTIR-PAS) aided by Principal Component Analysis (PCA) was used to identify differences between the intensities of the absorption bands related to functional groups. Thermal effusivity values between 592±3 and 610±4Ws 1/2 m -2 K -1 were measured using the photopyroelectric technique in a front detection configuration. The acidity index was between 1.11 and 1.27% and the density changed between 0.921 and 0.94g/mL. These variables, as well as the extraction yield between 12,6 and 14,4%, showed a similar behavior than that observed for the thermal effusivity, demonstrating that this parameter can be used as a criterion for discrimination between oil samples extracted from organic and conventional coffee beans. Copyright © 2017 Elsevier Ltd. All rights reserved.

  3. Ventilation and filtration techniques for handling aerosols produced by thermal cutting operations

    International Nuclear Information System (INIS)

    Bishop, A.

    1989-01-01

    This report describes the work done to characterize aerosols from thermal cutting operations and to develop suitable ventilation and filtration techniques. The work has been carried out under a research contract between the Windscale Laboratory and the Commission of the European Communities. The contract started in October 1984 and was completed in June 1988. The total cost of the work was UKL 132 000 of which 50% was funded by the Commission. This report has been compiled from the several progress reports submitted during the work period and details the main findings from the work programme. By working with colleagues from Commissariat a l'energie atomique, Saclay, France, additional useful data were collected. The bimodal size distribution of aerosols from oxypropane cutting was confirmed. Trials on various prefilters showed that the electrostatic precipitator (ESP) and the cartridge filter had excellent collection properties. From these trials the ESP was selected as the prefilter for the windscale advanced gas-cooled reactor (WAGR) decommissioning project. This work is presented in Appendix 1 to this report. Details are given of the proposals to modify the ESP to enable the safe removal of radioactive dust and contamined collector plates. Tests are described on aerosols generated by laser cutting and also trials on the ESP and high gradient magnetic separation prefilters. Finally, the measurement of filter burdens, aerosol concentrations and dust deposition rates from thermal cutting in a full-size ventilation rig are reported

  4. Fabrication and thermal oxidation of ZnO nano fibers prepared via electro spinning technique

    International Nuclear Information System (INIS)

    Baek, Jeongha; Park, Juyun; Kim, Don; Kang, Yongcheol; Koh, Sungwi; Kang, Jisoo

    2012-01-01

    Materials on the scale of nano scale have widely been used as research topics because of their interesting characteristics and aspects they bring into the field. Out of the many metal oxides, zinc oxide (ZnO) was chosen to be fabricated as nano fibers using the electro spinning method for potential uses of solar cells and sensors. After ZnO nano fibers were obtained, calcination temperature effects on the ZnO nano fibers were studied and reported here. The results of scanning electron microscopy (SEM) revealed that the aggregation of the ZnO nano fibers progressed by calcination. X-ray diffraction (XRD) study showed the hcp ZnO structure was enhanced by calcination at 873 and 1173 K. Transmission electron microscopy (TEM) confirmed the crystallinity of the calcined ZnO nano fibers. X-ray photoelectron spectroscopy (XPS) verified the thermal oxidation of Zn species by calcination in the nano fibers. These techniques have helped US deduce the facts that the diameter of ZnO increases as the calcination temperature was raised; the process of calcination affects the crystallinity of ZnO nano fibers, and the thermal oxidation of Zn species was observed as the calcination temperature was raised

  5. Application techniques of coatings by thermal projection; Tecnicas de aplicacion de recubrimientos por proyeccion termica

    Energy Technology Data Exchange (ETDEWEB)

    Porcayo Calderon, Jesus [Instituto de Investigaciones Electricas, Cuernavaca (Mexico)

    1995-12-31

    The coatings applied by thermal projection have an important number of applications in different industries (chemical, oil, electric, nuclear, etc.). The main purpose of the protection by means of coatings is to alter the surface characteristics of a component so as to resist corrosive environments, abrasion and erosion, among others. The coatings can be applied by different methods, but due to the fact that its characteristics appreciably differ from the base metal, it is important the knowledge of its properties when a coating is selected for a specific use. In this article the characteristics of the applied coatings by thermal projection, the factors that affect its performance and the principal application techniques, are described. [Espanol] Los recubrimientos aplicados por proyeccion termica tienen un numero importante de aplicaciones en diferentes industrias (quimica, petrolera, electrica, nuclear, etc.). El proposito principal de la proteccion por medio de recubrimientos es alterar las caracteristicas de la superficie de un componente de manera que resista ambientes corrosivos, abrasion y erosion, entre otros. Los recubrimientos pueden aplicarse por diferentes metodos, pero debido a que sus propiedades difieren apreciablemente de las del metal base, es importante el conocimiento de sus propiedades cuando se selecciona un recubrimiento para un uso especifico. En este articulo se describen las caracteristicas de los recubrimientos aplicados por proyeccion termica, los factores que afectan su desempeno y las principales tecnicas de aplicacion.

  6. Application techniques of coatings by thermal projection; Tecnicas de aplicacion de recubrimientos por proyeccion termica

    Energy Technology Data Exchange (ETDEWEB)

    Porcayo Calderon, Jesus [Instituto de Investigaciones Electricas, Cuernavaca (Mexico)

    1996-12-31

    The coatings applied by thermal projection have an important number of applications in different industries (chemical, oil, electric, nuclear, etc.). The main purpose of the protection by means of coatings is to alter the surface characteristics of a component so as to resist corrosive environments, abrasion and erosion, among others. The coatings can be applied by different methods, but due to the fact that its characteristics appreciably differ from the base metal, it is important the knowledge of its properties when a coating is selected for a specific use. In this article the characteristics of the applied coatings by thermal projection, the factors that affect its performance and the principal application techniques, are described. [Espanol] Los recubrimientos aplicados por proyeccion termica tienen un numero importante de aplicaciones en diferentes industrias (quimica, petrolera, electrica, nuclear, etc.). El proposito principal de la proteccion por medio de recubrimientos es alterar las caracteristicas de la superficie de un componente de manera que resista ambientes corrosivos, abrasion y erosion, entre otros. Los recubrimientos pueden aplicarse por diferentes metodos, pero debido a que sus propiedades difieren apreciablemente de las del metal base, es importante el conocimiento de sus propiedades cuando se selecciona un recubrimiento para un uso especifico. En este articulo se describen las caracteristicas de los recubrimientos aplicados por proyeccion termica, los factores que afectan su desempeno y las principales tecnicas de aplicacion.

  7. Single-molecule detection of dihydroazulene photo-thermal reaction using break junction technique

    Science.gov (United States)

    Huang, Cancan; Jevric, Martyn; Borges, Anders; Olsen, Stine T.; Hamill, Joseph M.; Zheng, Jue-Ting; Yang, Yang; Rudnev, Alexander; Baghernejad, Masoud; Broekmann, Peter; Petersen, Anne Ugleholdt; Wandlowski, Thomas; Mikkelsen, Kurt V.; Solomon, Gemma C.; Brøndsted Nielsen, Mogens; Hong, Wenjing

    2017-05-01

    Charge transport by tunnelling is one of the most ubiquitous elementary processes in nature. Small structural changes in a molecular junction can lead to significant difference in the single-molecule electronic properties, offering a tremendous opportunity to examine a reaction on the single-molecule scale by monitoring the conductance changes. Here, we explore the potential of the single-molecule break junction technique in the detection of photo-thermal reaction processes of a photochromic dihydroazulene/vinylheptafulvene system. Statistical analysis of the break junction experiments provides a quantitative approach for probing the reaction kinetics and reversibility, including the occurrence of isomerization during the reaction. The product ratios observed when switching the system in the junction does not follow those observed in solution studies (both experiment and theory), suggesting that the junction environment was perturbing the process significantly. This study opens the possibility of using nano-structured environments like molecular junctions to tailor product ratios in chemical reactions.

  8. Uncapped silver nanoparticles synthesized by DC arc thermal plasma technique for conductor paste formulation

    Science.gov (United States)

    Shinde, Manish; Pawar, Amol; Karmakar, Soumen; Seth, Tanay; Raut, Varsha; Rane, Sunit; Bhoraskar, Sudha; Amalnerkar, Dinesh

    2009-11-01

    Uncapped silver nanoparticles were synthesized by DC arc thermal plasma technique. The synthesized nanoparticles were structurally cubic and showed wide particle size variation (between 20-150 nm). Thick film paste formulated from such uncapped silver nanoparticles was screen-printed on alumina substrates and the resultant `green' films were fired at different firing temperatures. The films fired at 600 °C revealed better microstructure properties and also yielded the lowest value of sheet resistance in comparison to those corresponding to conventional peak firing temperature of 850 °C. Our findings directly support the role of silver nanoparticles in substantially depressing the operative peak firing temperature involved in traditional conductor thick films technology.

  9. Neutron spectral modulation as a new thermal neutron scattering technique. Pt. 1

    International Nuclear Information System (INIS)

    Ito, Y.; Nishi, M.; Motoya, K.

    1982-01-01

    A thermal neutron scattering technique is presented based on a new idea of labelling each neutron in its spectral position as well as in time through the scattering process. The method makes possible the simultaneous determination of both the accurate dispersion relation and its broadening by utilizing the resolution cancellation property of zero-crossing points in the cross-correlated time spectrum together with the Fourier transform scheme of the neutron spin echo without resorting to the echoing. The channel Fourier transform applied to the present method also makes possible the determination of the accurate direct energy scan profile of the scattering function with a rather broad incident neutron wavelength distribution. Therefore the intensity sacrifice for attaining high accurarcy is minimized. The technique is used with either a polarized or unpolarized beam at the sample position with no precautions against beam depolarization at the sample for the latter case. Relative time accurarcy of the order of 10 -3 to 10 -4 may be obtained for the general dispersion relation and for the quasi-elastic energy transfers using correspondingly the relative incident neutron wavelength spread of 10 to 1% around an incident neutron energy of a few meV. (orig.)

  10. Study of different biocomposite coatings on Ti alloy by a subsonic thermal spraying technique

    Energy Technology Data Exchange (ETDEWEB)

    Li Muqin [Provincial Key Laboratory of Biomaterials, Jiamusi University, Heilongjiang Province, 154007 (China); Zhang Rui [College of Stomatology, Jiamusi University, Heilongjiang Province, 154003 (China); Wang Jianping [College of Stomatology, Jiamusi University, Heilongjiang Province, 154003 (China); Yang Shiqin [State Key Laboratory Advanced Welding Production Technology, Harbin Institute of Technology, 150001 (China)

    2007-03-01

    A subsonic thermal spraying technique (STS) was used to make different biocomposite coatings on titanium alloys for preparing three kinds of implants: 8Ti2G, HA and 8H2B, respectively. The implants were embedded in a region of jaw of dogs whose teeth were pulled out three months previously. The dogs, in two groups, were killed 30 days and 90 days, respectively, after they were operated on. Osteointegration between the implants and host bone was investigated by x-ray, histology and the SEM technique. The results showed that the three kinds of coatings all exhibited good biocompatibility and synostosis, but their osteointegration capability showed a difference and decreased in the sequence of 8H2B, HA and 8Ti2G. The activity of coating, which promoted the reactions between implants and bone tissue, was further increased by the addition of bioglass in the 8H2B coating. Subsequently, chemical bonding was formed, and the osteointegration strength was increased. The study provided a new approach to prepare biocomposite coatings. The 8H2B implants, which formed an integral functional biocomposite coating on Ti alloys, showed a better osteointegration capability with bioactivity and pore gradient variation. A theoretical base was provided for the biocomposite coating application.

  11. An explanation for anomalous thermal conductivity behaviour in nanofluids as measured using the hot-wire technique

    International Nuclear Information System (INIS)

    Marín, E; Bedoya, A; Alvarado, S; Calderón, A; Ivanov, R; Gordillo-Delgado, F

    2014-01-01

    Several efforts have been made to explain thermal conductivity enhancements in fluids due to the addition of nanoparticles. However, until now, there has been no general consensus on this issue. In this work a simple experiment is described that demonstrates a possible cause of misinterpretation of the experimental data of thermal conductivity obtained when using the hot-wire technique (HWT) in these systems. It has been demonstrated that the thermal conductivity of a two-layer sample of two non-miscible phase systems determined by means of the HWT must be modelled using a series thermal resistance model with consideration of the interfacial layers between different phases. This result sheds light on the thermal conductivity enhancement in nanofluids with respect to the values corresponding to the base fluid, suggesting that this increase can be explained using the above-mentioned model and not by application of empirical formulae for effective media, as done before. (paper)

  12. A correction scheme for thermal conductivity measurement using the comparative cut-bar technique based on 3D numerical simulation

    International Nuclear Information System (INIS)

    Xing, Changhu; Folsom, Charles; Jensen, Colby; Ban, Heng; Marshall, Douglas W

    2014-01-01

    As an important factor affecting the accuracy of thermal conductivity measurement, systematic (bias) error in the guarded comparative axial heat flow (cut-bar) method was mostly neglected by previous researches. This bias is primarily due to the thermal conductivity mismatch between sample and meter bars (reference), which is common for a sample of unknown thermal conductivity. A correction scheme, based on finite element simulation of the measurement system, was proposed to reduce the magnitude of the overall measurement uncertainty. This scheme was experimentally validated by applying corrections on four types of sample measurements in which the specimen thermal conductivity is much smaller, slightly smaller, equal and much larger than that of the meter bar. As an alternative to the optimum guarding technique proposed before, the correction scheme can be used to minimize the uncertainty contribution from the measurement system with non-optimal guarding conditions. It is especially necessary for large thermal conductivity mismatches between sample and meter bars. (paper)

  13. Analytical techniques for determination and control of silica content in the water in thermal power plants

    Directory of Open Access Journals (Sweden)

    Ignjatović Nataša R.

    2015-01-01

    Full Text Available Ultrapure water with minimum contents of impurities is used for the preparation of steam in thermal power plants. More recently it has been found that the corrosion process is also influenced by sodium ions, chloride ions, and all forms of silicon in water. At higher temperatures and under high pressure the less soluble compounds of silicon are extracted, which form deposits on the walls of the boiler, the piping system and the turbine blades. Silicon is found in water in the form of different types (species which are characterized by specific physical and chemical properties. Distinctions can be made between highly reactive species of ionic (silicate anions and molecular forms (silicic acid and relatively inert types (suspended, colloidal, and polymerized silicon. The determination of various forms of silicon in water is a complex analytical task. This paper covers relevant research in the field of silicon specification analysis. Maintaining the unchanged, original composition of silicon species during various stages of analysis (sample collection, storage, and conservation has been given special attention. A large number of methods and procedures have been developed for the analysis of species of silicon, including chromatographic, spectroscopic and electrochemical techniques and combinations thereof. The techniques used for determining both the total amount and individual forms of silicon have been singled out. There is also an overview of the coupled techniques used most frequently in practice by using the methodology which involves preliminary separation of species and then individual specification. The paper offers an overview of analytical properties, advantages and disadvantages of the most representative analytical methods developed specifically for the analysis of silicon species in ultrapure water. The most important studies focusing on the silicon species in water have been highlighted and presented in detail. The determination of

  14. Optimum design of nonimaging Fresnel lens; Hiketsuzo fureneru renzu no saiteki sekkei

    Energy Technology Data Exchange (ETDEWEB)

    Leutz, R.; Komai, K.; Akisawa, A.; Kashiwagi, T. [Tokyo University of Agriculture and Technology, Tokyo (Japan); Suzuki, A. [Unesco, Paris (France). Associations in Japan

    1999-11-25

    An optimum convex shaped nonimaging Fresnel lens is designed following the edge ray principle. The lens is evaluated by tracing rays and calculating a projective optical concentration ratio. This Fresnel lens can used as concentrator in photovoltaic and solar thermal applications. (author)

  15. Bioinspired adaptive gradient refractive index distribution lens

    Science.gov (United States)

    Yin, Kezhen; Lai, Chuan-Yar; Wang, Jia; Ji, Shanzuo; Aldridge, James; Feng, Jingxing; Olah, Andrew; Baer, Eric; Ponting, Michael

    2018-02-01

    Inspired by the soft, deformable human eye lens, a synthetic polymer gradient refractive index distribution (GRIN) lens with an adaptive geometry and focal power has been demonstrated via multilayer coextrusion and thermoforming of nanolayered elastomeric polymer films. A set of 30 polymer nanolayered films comprised of two thermoplastic polyurethanes having a refractive index difference of 0.05 were coextruded via forced-assembly technique. The set of 30 nanolayered polymer films exhibited transmission near 90% with each film varying in refractive index by 0.0017. An adaptive GRIN lens was fabricated from a laminated stack of the variable refractive index films with a 0.05 spherical GRIN. This lens was subsequently deformed by mechanical ring compression of the lens. Variation in the optical properties of the deformable GRIN lens was determined, including 20% variation in focal length and reduced spherical aberration. These properties were measured and compared to simulated results by placido-cone topography and ANSYS methods. The demonstration of a solid-state, dynamic focal length, GRIN lens with improved aberration correction was discussed relative to the potential future use in implantable devices.

  16. Design Optimization of Liquid Fueled High Velocity Oxy- Fuel Thermal Spraying Technique for Durable Coating for Fossil Power Systems

    Energy Technology Data Exchange (ETDEWEB)

    Choudhuri, Ahsan [Univ. of Texas, El Paso, TX (United States); Love, Norman [Univ. of Texas, El Paso, TX (United States)

    2016-11-04

    High-velocity oxy–fuel (HVOF) thermal spraying was developed in 1930 and has been commercially available for twenty-five years. HVOF thermal spraying has several benefits over the more conventional plasma spray technique including a faster deposition rate which leads to quicker turn-around, with more durable coatings and higher bond strength, hardness and wear resistance due to a homogeneous distribution of the sprayed particles. HVOF thermal spraying is frequently used in engineering to deposit cermets, metallic alloys, composites and polymers, to enhance product life and performance. HVOF thermal spraying system is a highly promising technique for applying durable coatings on structural materials for corrosive and high temperature environments in advanced ultra-supercritical coal- fired (AUSC) boilers, steam turbines and gas turbines. HVOF thermal spraying is the preferred method for producing coatings with low porosity and high adhesion. HVOF thermal spray process has been shown to be one of the most efficient techniques to deposit high performance coatings at moderate cost. Variables affecting the deposit formation and coating properties include hardware characteristics such as nozzle geometry and spraying distance and process parameters such as equivalence ratio, gas flow density, and powder feedstock. In the spray process, the powder particles experience very high speeds combined with fast heating to the powder material melting point or above. This high temperature causes evaporation of the powder, dissolution, and phase transformations. Due to the complex nature of the HVOF technique, the control and optimization of the process is difficult. In general, good coating quality with suitable properties and required performance for specific applications is the goal in producing thermal spray coatings. In order to reach this goal, a deeper understanding of the spray process as a whole is needed. Although many researchers studied commercial HVOF thermal spray

  17. Development of a technique for level measurement in pressure vessels using thermal probes and artificial neural networks

    International Nuclear Information System (INIS)

    Torres, Walmir Maximo

    2008-01-01

    A technique for level measurement in pressure vessels was developed using thermal probes with internal cooling and artificial neural networks (ANN's). This new concept of thermal probes was experimentally tested in an experimental facility (BETSNI) with two test sections, ST1 and ST2. Two different thermal probes were designed and constructed: concentric tubes probe and U tube probe. A data acquisition system (DAS) was assembled to record the experimental data during the tests. Steady state and transient level tests were carried out and the experimental data obtained were used as learning and recall data sets in the ANN's program RETRO-05 that simulate a multilayer perceptron with backpropagation. The results of the analysis show that the technique can be applied for level measurements in pressure vessel. The technique is applied for a less input temperature data than the initially designed to the probes. The technique is robust and can be used in case of lack of some temperature data. Experimental data available in literature from electrically heated thermal probe were also used in the ANN's analysis producing good results. The results of the ANN's analysis show that the technique can be improved and applied to level measurements in pressure vessels. (author)

  18. Refractive neutron lens

    International Nuclear Information System (INIS)

    Petrov, P.V.; Kolchevsky, N.N.

    2013-01-01

    Model of the refractive neutron lens is proposed. System of N lenses acts as one thin lens with a complex refraction index n*. The maximum number N max of individual lenses for 'thick' neutron lens is calculated. Refractive neutron lens properties (resolution, focal depth) as function of resolution factor F 0 =ρbc/μ and depth of field factor dF 0 =λF 0 =λρbc/μ are calculated. It is shown that micro resolution of the refractive neutron optics is far from the wavelength in size and its open possibilities for progress in refractive neutron optics. (authors)

  19. Single-lens 3D digital image correlation system based on a bilateral telecentric lens and a bi-prism: validation and application.

    Science.gov (United States)

    Wu, Lifu; Zhu, Jianguo; Xie, Huimin

    2015-09-10

    By using the principle of stereovision, 3D digital image correlation (3D-DIC) can determine the 3D morphology and deformation of a target and has been widely used in experimental mechanics as a noncontact 3D measurement technique. To eliminate the limitations of the conventional 3D-DIC system, this study proposes a calibration-free single-lens 3D-DIC system based on a bilateral telecentric lens and a bi-prism. The performance of the proposed system is verified by tests of rigid-body translation along the out-of-plane direction. As a comparison, the same rigid-body translations are measured using a single-entocentric-lens 3D-DIC system. The results show that the measurement accuracy of the proposed system is higher than that of the entocentric-lens-based one. As an application, the proposed system is used to measure the thermal linear expansion of a ceramic plate at elevated temperatures. The reasonable measurement results verify its applicability in deformation measurements, even in high-temperature environments.

  20. Thermal expansion and density measurements of molten and solid materials at high temperatures by the gamma attenuation technique

    International Nuclear Information System (INIS)

    Drotning, W.D.

    1979-05-01

    An apparatus is described for the measurement of the density and thermal expansion of molten materials to 3200 0 K using the gamma attenuation technique. The precision of the experimental technique was analytically examined for both absolute and relative density determinations. Three analytical expressions used to reduce data for liquid density determinations were evaluated for their precision. Each allows use of a different set of input data parameters, which can be chosen based on experimental considerations. Using experimentally reasonable values for the precision of the parameters yields a similar resultant density precision from the three methods, on the order of 0.2%. The analytical method for measurements of the linear thermal expansion of solids by the gamma method is also described. To demonstrate the use of the technique on reasonably well-characterized systems, data are presented for (1) the density and thermal expansion of molten tin, lead, and aluminum to 1300 0 K, (2) the thermal expansion of solid aluminum to the melting point, and (3) the thermal expansion of a low melting point glass through the transition temperature and melting region. The data agree very well with published results using other methods where such published data exist

  1. The measuring technique developed to evaluate the thermal diffusivity of the multi-layered thin film specimens

    Directory of Open Access Journals (Sweden)

    Li Tse-Chang

    2017-01-01

    Full Text Available In the present study, the thermal diffusivities of the Al, Si and ITO films deposited on the SUS304 steel substrate are evaluated via the present technique. Before applying this technique, the temperature for the thin film of the multi-layered specimen is developed theoretically for the one- dimensional steady heat conduction in response to amplitude and frequency of the periodically oscillating temperature imposed by a peltier placed beneath the specimen's substrate. By the thermal-electrical data processing system excluding the lock-in amplifier, the temperature frequency a3 has been proved first to be independent of the electrical voltage applied to the peltier and the contact position of the thermocouples. The experimental data of phase difference for three kinds of specimen are regressed well by a straight line with a slope. Then, the thermal diffusivity of the thin film is thus determined if the slope value and the film- thickness are available. In the present arrangements for the thermocouples, two thermal diffusivity values are quite close each other and valid for every kind of specimen. This technique can provide an efficient, low-cost method for the thermal diffusivity measurements of thin films.

  2. Life Management Technique of Thermal Fatigue for SMST Boiler Tube at Different Heating Zone Using Smithy Furnace

    OpenAIRE

    Shekhar Pal,; Pradeep Suman

    2014-01-01

    This paper highlights on the evaluation of thermal fatigue failure for SMST (Salzgitter Mannesmann strain less boiler tube) DMV 304 HCu boiler tube using life management technique by using of smithy furnace. Boiler tubes are highly affected by operating conditions like, high temperature and high pressure. So it needs periodic checking for the purpose of safety and health assessment of the plant. So using this technique we can identify the degradation of tubes at microstructure...

  3. Thermal behaviour of hafnium diethylenetriaminepentaacetate studied using the perturbed angular correlation technique

    Energy Technology Data Exchange (ETDEWEB)

    Chain, Cecilia Y. [Universidad Nacional de La Plata (Argentina). Dept. de Fisica; Consejo Nacional de Investigaciones Cientificas y Tecnicas (CONICET), La Plata (Argentina). IFLP-CCT; Consejo Nacional de Investigaciones Cientificas y Tecnicas, Buenos Aires (Argentina); Rivas, Patricia [Consejo Nacional de Investigaciones Cientificas y Tecnicas (CONICET), La Plata (Argentina). IFLP-CCT; Consejo Nacional de Investigaciones Cientificas y Tecnicas, Buenos Aires (Argentina); Universidad Nacional de La Plata (Argentina). Facultad de Ciencias Agrarias y Forestales; Pasquevich, Alberto F. [Universidad Nacional de La Plata (Argentina). Dept. de Fisica; Consejo Nacional de Investigaciones Cientificas y Tecnicas (CONICET), La Plata (Argentina). IFLP-CCT; Comision de Investigaciones Cientificas de la Provincia de Buenos Aires (CIC-PBA) (Argentina)

    2014-07-01

    Polyaminecarboxilic ligands like diethylenetriaminepentaacetic acid form stable complexes with many heavy metal ions, excelling as cation chelants especially in the field of radiopharmacy. The aim of this work is to characterize, by using the Time Differential Perturbed Angular Correlations (TDPAC) technique, the hyperfine interactions at hafnium sites in hafnium diethylenetriaminepentaacetate and to investigate their evolution as temperature increases. TDPAC results for KHfDTPA.3H{sub 2}O obtained by chemical synthesis yield a well defined and highly asymmetric interaction of quadrupole frequency ω{sub Q} = 141 Mrad/s, which is consistent with the existence of a unique site for the metal in the crystal lattice. The thermal behaviour of the chelate is investigated by means of differential scanning calorimetry and thermogravimetrical analyses revealing that an endothermic dehydration of KHfDTPA.3H{sub 2}O takes place in one step between 80 C and 180 C. The anhydrous KHfDTPA thus arising is characterized by a fully asymmetric and well defined interaction of quadrupole frequency ω{sub Q} = 168 Mrad/s. (orig.)

  4. Thermal behaviour of hafnium diethylenetriaminepentaacetate studied using the perturbed angular correlation technique

    International Nuclear Information System (INIS)

    Chain, Cecilia Y.; Rivas, Patricia

    2014-01-01

    Polyaminecarboxilic ligands like diethylenetriaminepentaacetic acid form stable complexes with many heavy metal ions, excelling as cation chelants especially in the field of radiopharmacy. The aim of this work is to characterize, by using the Time Differential Perturbed Angular Correlations (TDPAC) technique, the hyperfine interactions at hafnium sites in hafnium diethylenetriaminepentaacetate and to investigate their evolution as temperature increases. TDPAC results for KHfDTPA.3H 2 O obtained by chemical synthesis yield a well defined and highly asymmetric interaction of quadrupole frequency ω Q = 141 Mrad/s, which is consistent with the existence of a unique site for the metal in the crystal lattice. The thermal behaviour of the chelate is investigated by means of differential scanning calorimetry and thermogravimetrical analyses revealing that an endothermic dehydration of KHfDTPA.3H 2 O takes place in one step between 80 C and 180 C. The anhydrous KHfDTPA thus arising is characterized by a fully asymmetric and well defined interaction of quadrupole frequency ω Q = 168 Mrad/s. (orig.)

  5. Studies of implicit and explicit solution techniques in transient thermal analysis of structures

    International Nuclear Information System (INIS)

    Adelman, H.M.; Haftka, R.T.; Robinson, J.C.

    1982-08-01

    Studies aimed at an increase in the efficiency of calculating transient temperature fields in complex aerospace vehicle structures are reported. The advantages and disadvantages of explicit and implicit algorithms are discussed and a promising set of implicit algorithms with variable time steps, known as GEARIB, is described. Test problems, used for evaluating and comparing various algorithms, are discussed and finite element models of the configurations are described. These problems include a coarse model of the Space Shuttle wing, an insulated frame test article, a metallic panel for a thermal protection system, and detailed models of sections of the Space Shuttle wing. Results generally indicate a preference for implicit over explicit algorithms for transient structural heat transfer problems when the governing equations are stiff (typical of many practical problems such as insulated metal structures). The effects on algorithm performance of different models of an insulated cylinder are demonstrated. The stiffness of the problem is highly sensitive to modeling details and careful modeling can reduce the stiffness of the equations to the extent that explicit methods may become the best choice. Preliminary applications of a mixed implicit-explicit algorithm and operator splitting techniques for speeding up the solution of the algebraic equations are also described

  6. Studies of implicit and explicit solution techniques in transient thermal analysis of structures

    Science.gov (United States)

    Adelman, H. M.; Haftka, R. T.; Robinson, J. C.

    1982-01-01

    Studies aimed at an increase in the efficiency of calculating transient temperature fields in complex aerospace vehicle structures are reported. The advantages and disadvantages of explicit and implicit algorithms are discussed and a promising set of implicit algorithms with variable time steps, known as GEARIB, is described. Test problems, used for evaluating and comparing various algorithms, are discussed and finite element models of the configurations are described. These problems include a coarse model of the Space Shuttle wing, an insulated frame tst article, a metallic panel for a thermal protection system, and detailed models of sections of the Space Shuttle wing. Results generally indicate a preference for implicit over explicit algorithms for transient structural heat transfer problems when the governing equations are stiff (typical of many practical problems such as insulated metal structures). The effects on algorithm performance of different models of an insulated cylinder are demonstrated. The stiffness of the problem is highly sensitive to modeling details and careful modeling can reduce the stiffness of the equations to the extent that explicit methods may become the best choice. Preliminary applications of a mixed implicit-explicit algorithm and operator splitting techniques for speeding up the solution of the algebraic equations are also described.

  7. REAL TIME PULVERISED COAL FLOW SOFT SENSOR FOR THERMAL POWER PLANTS USING EVOLUTIONARY COMPUTATION TECHNIQUES

    Directory of Open Access Journals (Sweden)

    B. Raja Singh

    2015-01-01

    Full Text Available Pulverised coal preparation system (Coal mills is the heart of coal-fired power plants. The complex nature of a milling process, together with the complex interactions between coal quality and mill conditions, would lead to immense difficulties for obtaining an effective mathematical model of the milling process. In this paper, vertical spindle coal mills (bowl mill that are widely used in coal-fired power plants, is considered for the model development and its pulverised fuel flow rate is computed using the model. For the steady state coal mill model development, plant measurements such as air-flow rate, differential pressure across mill etc., are considered as inputs/outputs. The mathematical model is derived from analysis of energy, heat and mass balances. An Evolutionary computation technique is adopted to identify the unknown model parameters using on-line plant data. Validation results indicate that this model is accurate enough to represent the whole process of steady state coal mill dynamics. This coal mill model is being implemented on-line in a 210 MW thermal power plant and the results obtained are compared with plant data. The model is found accurate and robust that will work better in power plants for system monitoring. Therefore, the model can be used for online monitoring, fault detection, and control to improve the efficiency of combustion.

  8. The low thermal gradient CZ technique as a way of growing of dislocation-free germanium crystals

    Science.gov (United States)

    Moskovskih, V. A.; Kasimkin, P. V.; Shlegel, V. N.; Vasiliev, Y. V.; Gridchin, V. A.; Podkopaev, O. I.

    2014-09-01

    This paper considers the possibility of growth of dislocation-free germanium single crystals. This is achieved by reducing the temperature gradients at the level of 1 K/cm and lower. Single germanium crystals 45-48 mm in diameter with a dislocation density of 102 cm-2 were grown by a Low Thermal Gradient Czochralski technique (LTG CZ).

  9. Study of the aging processes in polyurethane adhesives using thermal treatment and differential calorimetric, dielectric, and mechanical techniques ; 1, identifying the aging processes ; 2, quantifying the aging effect

    CERN Document Server

    Althouse, L P

    1979-01-01

    Study of the aging processes in polyurethane adhesives using thermal treatment and differential calorimetric, dielectric, and mechanical techniques ; 1, identifying the aging processes ; 2, quantifying the aging effect

  10. Modelling of thermal field and point defect dynamics during silicon single crystal growth using CZ technique

    Science.gov (United States)

    Sabanskis, A.; Virbulis, J.

    2018-05-01

    Mathematical modelling is employed to numerically analyse the dynamics of the Czochralski (CZ) silicon single crystal growth. The model is axisymmetric, its thermal part describes heat transfer by conduction and thermal radiation, and allows to predict the time-dependent shape of the crystal-melt interface. Besides the thermal field, the point defect dynamics is modelled using the finite element method. The considered process consists of cone growth and cylindrical phases, including a short period of a reduced crystal pull rate, and a power jump to avoid large diameter changes. The influence of the thermal stresses on the point defects is also investigated.

  11. Introducing Thermal Wave Transport Analysis (TWTA): A Thermal Technique for Dopamine Detection by Screen-Printed Electrodes Functionalized with Molecularly Imprinted Polymer (MIP) Particles.

    Science.gov (United States)

    Peeters, Marloes M; van Grinsven, Bart; Foster, Christopher W; Cleij, Thomas J; Banks, Craig E

    2016-04-26

    A novel procedure is developed for producing bulk modified Molecularly Imprinted Polymer (MIP) screen-printed electrodes (SPEs), which involves the direct mixing of the polymer particles within the screen-printed ink. This allowed reduction of the sample preparation time from 45 min to 1 min, and resulted in higher reproducibility of the electrodes. The samples are measured with a novel detection method, namely, thermal wave transport analysis (TWTA), relying on the analysis of thermal waves through a functional interface. As a first proof-of-principle, MIPs for dopamine are developed and successfully incorporated within a bulk modified MIP SPE. The detection limits of dopamine within buffer solutions for the MIP SPEs are determined via three independent techniques. With cyclic voltammetry this was determined to be 4.7 × 10(-6) M, whereas by using the heat-transfer method (HTM) 0.35 × 10(-6) M was obtained, and with the novel TWTA concept 0.26 × 10(-6) M is possible. This TWTA technique is measured simultaneously with HTM and has the benefits of reducing measurement time to less than 5 min and increasing effect size by nearly a factor of two. The two thermal methods are able to enhance dopamine detection by one order of magnitude compared to the electrochemical method. In previous research, it was not possible to measure neurotransmitters in complex samples with HTM, but with the improved signal-to-noise of TWTA for the first time, spiked dopamine concentrations were determined in a relevant food sample. In summary, novel concepts are presented for both the sensor functionalization side by employing screen-printing technology, and on the sensing side, the novel TWTA thermal technique is reported. The developed bio-sensing platform is cost-effective and suitable for mass-production due to the nature of screen-printing technology, which makes it very interesting for neurotransmitter detection in clinical diagnostic applications.

  12. Capsular 'pits' in the human lens.

    OpenAIRE

    Harris, M. L.; Brown, N. A.; Shun-Shin, G. A.; Smith, G. T.

    1992-01-01

    The lens capsule is an atypical basement membrane surrounding the lens epithelial cells and lens fibres which make up the remainder of the human lens. A seemingly unreported morphological change visible in the lens capsule with the biomicroscope is described.

  13. Leakage investigation in an underground cooling water pipeline at a thermal power station using radiotracer technique

    International Nuclear Information System (INIS)

    Khan, I.H.; Din, U.G.; Gul, S.; Farooq, M.; Qureshi, R.M.

    2004-05-01

    The objective of this study was to locate the leakage point(s) in an underground cooling water pipeline of a Thermal Power Station for pre-shutdown planning purposes. The internal diameter of the pipeline was 2240 mm with 12 mm with 12 (mild steel) wall thickness and it was buried under 1.0 meter reinforced concrete and 0.5-1.0 meter soil/sand cover. The volume flow rate of the pipeline was 29043 m/sup 3/hour at 2kg/cm/sup 2/ pressure. The linear speed of water flowing inside the pipeline was around 2 m/sec. This gave rise to a very high volume fast moving system. Radiotracer technique was used to investigate the problem under investigation. About 50 mCi of /sup 131/I radiotracer, in the form of NaI solution, was injected into the system and radiotracer evolution near suspected leakage point(s) was monitored using radiation detectors (NaI, 2 x 2 inch crystal size). Seven detectors were installed around three teeing off pipes (leakage area) inside the plant building and one at the injection point near the pump outlet. On line data acquisition system was used to acquire the radiotracer data. The leakage water was exiting from the floor just along the pipes carrying main flow of water. The time lag between the arrival, at detectors, of radiotracer flowing inside the pipeline and that present in the leakage water (outside the pipeline) was exploited to identify the position of leakage. The tracer test revealed that there was leakage at two points. The leakage at one point was small as compared at the other points. (author)

  14. Synthesis of carbon nanotubes using the cobalt nanocatalyst by thermal chemical vapor deposition technique

    Energy Technology Data Exchange (ETDEWEB)

    Madani, S.S. [Department of Chemistry, Science and Research Branch, Islamic Azad University, Tehran (Iran, Islamic Republic of); Zare, K. [Department of Chemistry, Science and Research Branch, Islamic Azad University, Tehran (Iran, Islamic Republic of); Department of Chemistry, Shahid Beheshti University, Tehran (Iran, Islamic Republic of); Ghoranneviss, M. [Plasma Physics Research Center, Science and Research Branch, Islamic Azad University, Tehran (Iran, Islamic Republic of); Salar Elahi, A., E-mail: Salari_phy@yahoo.com [Plasma Physics Research Center, Science and Research Branch, Islamic Azad University, Tehran (Iran, Islamic Republic of)

    2015-11-05

    The three main synthesis methods of Carbon nanotubes (CNTs) are the arc discharge, the laser ablation and the chemical vapour deposition (CVD) with a special regard to the latter one. CNTs were produced on a silicon wafer by Thermal Chemical Vapor Deposition (TCVD) using acetylene as a carbon source, cobalt as a catalyst and ammonia as a reactive gas. The DC-sputtering system was used to prepare cobalt thin films on Si substrates. A series of experiments was carried out to investigate the effects of reaction temperature and deposition time on the synthesis of the nanotubes. The deposition time was selected as 15 and 25 min for all growth temperatures. Energy Dispersive X-ray (EDX) measurements were used to investigate the elemental composition of the Co nanocatalyst deposited on Si substrates. Atomic Force Microscopy (AFM) was used to characterize the surface topography of the Co nanocatalyst deposited on Si substrates. The as-grown CNTs were characterized under Field Emission Scanning Electron Microscopy (FESEM) to study the morphological properties of CNTs. Also, the grown CNTs have been investigated by High Resolution Transmission Electron Microscopy (HRTEM) and Raman spectroscopy. The results demonstrated that increasing the temperature leads to increasing the diameter of CNTs. The ideal reaction temperature was 850 °C and the deposition time was 15 min. - Graphical abstract: FESEM images of CNTs grown on the cobalt catalyst at growth temperatures of (a) 850 °C, (b) 900 °C, (c) 950 °C and (d) 1000 °C during the deposition time of 15 min. - Highlights: • Carbon nanotubes (CNTs) were produced on a silicon wafer by TCVD technique. • EDX and AFM were used to investigate the elemental composition and surface topography. • FESEM was used to study the morphological properties of CNTs. • The grown CNTs have been investigated by HRTEM and Raman spectroscopy.

  15. Some application of the thermal analysis technique to nuclear material process

    International Nuclear Information System (INIS)

    Xi Chongpu.

    1987-01-01

    This paper briefly described the thermal stability and phase transformation of Uranium Compounds as UF 4 , UO 2 F 2 , UO 2 -(NO 3 ) 2 , ADU, AUC, UO 3 and UO 2 . It proved that the thermal analysis finds extensive application in nuclear materials prodcution

  16. Industrial implementation of plasma deposition using the expanding thermal plasma technique

    NARCIS (Netherlands)

    Sanden, van de M.C.M.; Oever, van den P.J.; Creatore, M.; Schaepkens, M.; Miebach, T.; Iacovangelo, C.D.; Bosch, R.C.M.; Bijker, M.D.; Evers, M.F.J.; Schram, D.C.; Kessels, W.M.M.

    2004-01-01

    Two successful industrial implementations of the expanding thermal plasma setup, a novel plasma source, obtaining high deposition rate are discussed. The Ar/O2/hexamethyldisiloxane and Ar/O2/octamethyl-cyclosiloxane-fed expanding thermal plasma setup is used to deposit scratch resistant silicone

  17. Experimental investigation for determination of thermal effects in a Nd: YAG laser crystal by use of interferometry technique

    International Nuclear Information System (INIS)

    Safary, E.; Movahedinejad, H.; Razzaghi, H.; Haj Esmaeilbeigi, F.; Tohidi, T.; Shiri, M.

    2007-01-01

    Thermal effects have an important role in high power solid state laser designing. Known of this effect and their roles on intensity and quality of output beam needs so many experiments. In this paper, we focused on influence of temperature distribution on thermal lensing in the Nd:YAG laser by use of interferometry technique. Then we used from a plariscop set up for describing of intensity reduce and distortion of the wave shape when it use from the Polaroid into the resonator at side pump.

  18. Particle swarm optimization applied to automatic lens design

    Science.gov (United States)

    Qin, Hua

    2011-06-01

    This paper describes a novel application of Particle Swarm Optimization (PSO) technique to lens design. A mathematical model is constructed, and merit functions in an optical system are employed as fitness functions, which combined radiuses of curvature, thicknesses among lens surfaces and refractive indices regarding an optical system. By using this function, the aberration correction is carried out. A design example using PSO is given. Results show that PSO as optical design tools is practical and powerful, and this method is no longer dependent on the lens initial structure and can arbitrarily create search ranges of structural parameters of a lens system, which is an important step towards automatic design with artificial intelligence.

  19. Reduction of thermal models of buildings: improvement of techniques using meteorological influence models; Reduction de modeles thermiques de batiments: amelioration des techniques par modelisation des sollicitations meteorologiques

    Energy Technology Data Exchange (ETDEWEB)

    Dautin, S.

    1997-04-01

    This work concerns the modeling of thermal phenomena inside buildings for the evaluation of energy exploitation costs of thermal installations and for the modeling of thermal and aeraulic transient phenomena. This thesis comprises 7 chapters dealing with: (1) the thermal phenomena inside buildings and the CLIM2000 calculation code, (2) the ETNA and GENEC experimental cells and their modeling, (3) the techniques of model reduction tested (Marshall`s truncature, Michailesco aggregation method and Moore truncature) with their algorithms and their encoding in the MATRED software, (4) the application of model reduction methods to the GENEC and ETNA cells and to a medium size dual-zone building, (5) the modeling of meteorological influences classically applied to buildings (external temperature and solar flux), (6) the analytical expression of these modeled meteorological influences. The last chapter presents the results of these improved methods on the GENEC and ETNA cells and on a lower inertia building. These new methods are compared to classical methods. (J.S.) 69 refs.

  20. Ground-based thermal imaging of stream surface temperatures: Technique and evaluation

    Science.gov (United States)

    Bonar, Scott A.; Petre, Sally J.

    2015-01-01

    We evaluated a ground-based handheld thermal imaging system for measuring water temperatures using data from eight southwestern USA streams and rivers. We found handheld thermal imagers could provide considerably more spatial information on water temperature (for our unit one image = 19,600 individual temperature measurements) than traditional methods could supply without a prohibitive amount of effort. Furthermore, they could provide measurements of stream surface temperature almost instantaneously compared with most traditional handheld thermometers (e.g., >20 s/reading). Spatial temperature analysis is important for measurement of subtle temperature differences across waterways, and identification of warm and cold groundwater inputs. Handheld thermal imaging is less expensive and equipment intensive than airborne thermal imaging methods and is useful under riparian canopies. Disadvantages of handheld thermal imagers include their current higher expense than thermometers, their susceptibility to interference when used incorrectly, and their slightly lower accuracy than traditional temperature measurement methods. Thermal imagers can only measure surface temperature, but this usually corresponds to subsurface temperatures in well-mixed streams and rivers. Using thermal imaging in select applications, such as where spatial investigations of water temperature are needed, or in conjunction with stationary temperature data loggers or handheld electronic or liquid-in-glass thermometers to characterize stream temperatures by both time and space, could provide valuable information on stream temperature dynamics. These tools will become increasingly important to fisheries biologists as costs continue to decline.

  1. Intraocular lens fabrication

    Energy Technology Data Exchange (ETDEWEB)

    Salazar, Mike A. (Albuquerque, NM); Foreman, Larry R. (Los Alamos, NM)

    1997-01-01

    This invention describes a method for fabricating an intraocular lens made rom clear Teflon.TM., Mylar.TM., or other thermoplastic material having a thickness of about 0.025 millimeters. These plastic materials are thermoformable and biocompatable with the human eye. The two shaped lenses are bonded together with a variety of procedures which may include thermosetting and solvent based adhesives, laser and impulse welding, and ultrasonic bonding. The fill tube, which is used to inject a refractive filling material is formed with the lens so as not to damage the lens shape. A hypodermic tube may be included inside the fill tube.

  2. Intraocular lens fabrication

    Energy Technology Data Exchange (ETDEWEB)

    Salazar, M.A.; Foreman, L.R.

    1997-07-08

    This invention describes a method for fabricating an intraocular lens made from clear Teflon{trademark}, Mylar{trademark}, or other thermoplastic material having a thickness of about 0.025 millimeters. These plastic materials are thermoformable and biocompatable with the human eye. The two shaped lenses are bonded together with a variety of procedures which may include thermosetting and solvent based adhesives, laser and impulse welding, and ultrasonic bonding. The fill tube, which is used to inject a refractive filling material is formed with the lens so as not to damage the lens shape. A hypodermic tube may be included inside the fill tube. 13 figs.

  3. Measurement of thermal conductivity of uranium metal using transient plane source technique

    International Nuclear Information System (INIS)

    Subramanian, G.G.S.; Bapuji, T.; Panneerselvam, G.; Antony, M.P.; Nagarajan, K.

    2012-01-01

    Thermo physical properties of fuel, cladding and structural materials play a significant role in the reactor operation. Thermal conductivity is one of the most important physical properties of the fuel which determines the maximum linear heat rating of the fuel in a reactor. As part of this study, the thermal conductivity of uranium metal was measured using a transient plane source (TPS) by Hot-disc method

  4. A thermal technique for local ultrasound intensity measurement: part 2. Application to exposimetry on a medical diagnostic device

    International Nuclear Information System (INIS)

    Wilkens, V

    2010-01-01

    Acoustic output measurements on medical ultrasound equipment are usually performed using radiation force balances to determine the output power and using hydrophones to determine pressure and intensity parameters. The local temporal-average ultrasound intensity can be measured alternatively by thermal sensors. The technique was described and prototype sensors were characterized in a preceding paper. Here, the application of such a thermal intensity sensor to the output beam characterization of a typical medical diagnostic device is described. Two transducers, a 7.5 MHz linear array and a 3.5 MHz convex array were investigated in different operating modes. For comparison, hydrophone measurements were also performed. If the spatial averaging effect is taken into account, good agreement is found between both measurement methods. The maximum deviations of the spatial-peak temporal-average intensities I SPTA obtained with the thermal sensor from the corresponding hydrophone-based results were below 12%. The simple thermal technique offers advantages for intensity measurements especially in the case of scanning and combined modes of the diagnostic device, where the synchronization between hydrophone measurements and the complex pulse emission pattern can be difficult

  5. Pulsed-laser time-resolved thermal mirror technique in low-absorbance homogeneous linear elastic materials.

    Science.gov (United States)

    Lukasievicz, Gustavo V B; Astrath, Nelson G C; Malacarne, Luis C; Herculano, Leandro S; Zanuto, Vitor S; Baesso, Mauro L; Bialkowski, Stephen E

    2013-10-01

    A theoretical model for a time-resolved photothermal mirror technique using pulsed-laser excitation was developed for low absorption samples. Analytical solutions to the temperature and thermoelastic deformation equations are found for three characteristic pulse profiles and are compared to finite element analysis methods results for finite samples. An analytical expression for the intensity of the center of a continuous probe laser at the detector plane is derived using the Fresnel diffraction theory, which allows modeling of experimental results. Experiments are performed in optical glasses, and the models are fitted to the data. The parameters of the fit are in good agreement with previous literature data for absorption, thermal diffusion, and thermal expansion of the materials tested. The combined modeling and experimental techniques are shown to be useful for quantitative determination of the physical properties of low absorption homogeneous linear elastic material samples.

  6. Advanced neutron and X-ray techniques for insights into the microstructure of EB-PVD thermal barrier coatings

    Energy Technology Data Exchange (ETDEWEB)

    Kulkarni, Anand [State University of New York, Stony Brook, NY 11794 (United States); Goland, Allen [State University of New York, Stony Brook, NY 11794 (United States); Herman, Herbert [State University of New York, Stony Brook, NY 11794 (United States)]. E-mail: hherman@ms.cc.sunysb.edu; Allen, Andrew J. [National Institute of Standards and Technology, Gaithersburg, MD 20899 (United States); Dobbins, Tabbetha [National Institute of Standards and Technology, Gaithersburg, MD 20899 (United States); DeCarlo, Francesco [Argonne National Laboratory, Argonne, IL 60439 (United States); Ilavsky, Jan [Argonne National Laboratory, Argonne, IL 60439 (United States); Long, Gabrielle G. [Argonne National Laboratory, Argonne, IL 60439 (United States); Fang, Stacy [Chromalloy Gas Turbine Corporation, Orangeburg, NY 10962 (United States); Lawton, Paul [Chromalloy Gas Turbine Corporation, Orangeburg, NY 10962 (United States)

    2006-06-25

    The ongoing quest to increase gas turbine efficiency and performance (increased thrust) provides a driving force for materials development. While improved engine design and usage of novel materials provide solutions for increased engine operating temperatures, and hence fuel efficiency, reliability issues remain. Thermal barrier coatings (TBCs), deposited onto turbine components using the electron-beam physical vapor deposition (EB-PVD) process, exhibit unique pore architectures capable of bridging the technological gap between insulation/life extension and prime reliance. This article explores the potential of advanced X-ray and neutron techniques for comprehension of an EB-PVD TBC coating microstructure. While conventional microscopy reveals a hierarchy of voids, complementary advanced techniques allow quantification of these voids in terms of component porosities, anisotropy, size and gradient through the coating thickness. In addition, the derived microstructural parameters obtained both further knowledge of the nature and architecture of the porosity, and help establish its influence on the resultant thermal and mechanical properties.

  7. Novel Technique to Overcome the Nonavailability of a Long Needle 9-0 Polypropylene Suture for Sutured Scleral Fixation of the Posterior Chamber Intraocular Lens Using a Single Fisherman’s Knot

    Directory of Open Access Journals (Sweden)

    Yong Un Shin

    2017-01-01

    Full Text Available Purpose. To describe a method to overcome the nonavailability of a long needle 9-0 polypropylene suture for sutured scleral fixation of the posterior chamber intraocular lens (PC-IOL using a single fisherman’s knot (SFK. Methods. First, a 10-0 polypropylene suture was passed from the sclera to the ciliary sulcus using a long needle. A 9-0 suture was tied to the unpassed portion of the 10-0 suture with an SFK. We pulled the 10-0 suture to pass the SFK through the sclera, and then we cut the knot and removed the 10-0 suture. IOL fixation with 9-0 sutures used the conventional techniques used for sutured scleral-fixated IOL. Preoperative and postoperative visual acuity, corneal astigmatism, and endothelial cell count and intraoperative/postoperative complications were evaluated. Results. An SFK joining the two sutures was passed through the sclera without breakage or slippage. A total of 35 eyes from 35 patients who underwent sutured scleral fixation of the IOL. An intraoperative complication (minor intraocular hemorrhage was recorded in four cases. Knot exposure, IOL dislocation, subluxation, and retinal detachment were not observed. Conclusions. The SFK offers the opportunity to use 9-0 sutures for the long-term safety and may not require the surgeon to learn any new technique.

  8. Novel Technique to Overcome the Nonavailability of a Long Needle 9-0 Polypropylene Suture for Sutured Scleral Fixation of the Posterior Chamber Intraocular Lens Using a Single Fisherman's Knot.

    Science.gov (United States)

    Shin, Yong Un; Seong, Mincheol; Cho, Hee Yoon; Kang, Min Ho

    2017-01-01

    To describe a method to overcome the nonavailability of a long needle 9-0 polypropylene suture for sutured scleral fixation of the posterior chamber intraocular lens (PC-IOL) using a single fisherman's knot (SFK). First, a 10-0 polypropylene suture was passed from the sclera to the ciliary sulcus using a long needle. A 9-0 suture was tied to the unpassed portion of the 10-0 suture with an SFK. We pulled the 10-0 suture to pass the SFK through the sclera, and then we cut the knot and removed the 10-0 suture. IOL fixation with 9-0 sutures used the conventional techniques used for sutured scleral-fixated IOL. Preoperative and postoperative visual acuity, corneal astigmatism, and endothelial cell count and intraoperative/postoperative complications were evaluated. An SFK joining the two sutures was passed through the sclera without breakage or slippage. A total of 35 eyes from 35 patients who underwent sutured scleral fixation of the IOL. An intraoperative complication (minor intraocular hemorrhage) was recorded in four cases. Knot exposure, IOL dislocation, subluxation, and retinal detachment were not observed. The SFK offers the opportunity to use 9-0 sutures for the long-term safety and may not require the surgeon to learn any new technique.

  9. Colored Contact Lens Dangers

    Medline Plus

    Full Text Available ... One Use Facts About Colored Contacts and Halloween Safety Colored Contact Lens Facts Over-the-Counter Costume ... Costume Contact Lenses Can Ruin Vision Eye Makeup Safety In fact, it is illegal to sell colored ...

  10. Colored Contact Lens Dangers

    Medline Plus

    Full Text Available ... One Use Facts About Colored Contacts and Halloween Safety Colored Contact Lens Facts Over-the-Counter Costume ... new application of artificial intelligence shows whether a patient’s eyes point to high blood pressure or risk ...

  11. The lens and cataracts.

    Science.gov (United States)

    Matthews, Andrew G

    2004-08-01

    It is conservatively estimated that some form of lens opacity is present in 5% to 7% of horses with otherwise clinically normal eyes.These opacities can range from small epicapsular remnants of the fetal vasculature to dense and extensive cataract. A cataract is defined technically as any opacity or alteration in the optical homogeneity of the lens involving one or more of the following: anterior epithelium, capsule, cortex, or nucleus. In the horse, cataracts rarely involve the entire lens structure (ie, complete cataracts) and are more usually localized to one anatomic landmark or sector of the lens. Complete cataracts are invariably associated with overt and significant visual disability. Focal or incomplete cataracts alone seldom cause any apparent visual dysfunction in affected horses,however.

  12. Colored Contact Lens Dangers

    Medline Plus

    Full Text Available ... One Use Facts About Colored Contacts and Halloween Safety Colored Contact Lens Facts Over-the-Counter Costume ... use of colored contact lenses , from the U.S. Food and Drug Administration (FDA). Are the colored lenses ...

  13. Colored Contact Lens Dangers

    Medline Plus

    Full Text Available ... sell contacts without a prescription are breaking the law, and may be fined $11,000 per violation. " ... wear any kind of contact lens. In Butler's case, the lenses caused an infection and left her ...

  14. Colored Contact Lens Dangers

    Medline Plus

    Full Text Available ... contacto de color Sep. 26, 2013 It started as an impulsive buy from a souvenir shop, but ... require the same level of care or consideration as a standard contact lens because they can be ...

  15. Colored Contact Lens Dangers

    Medline Plus

    Full Text Available ... With Proper Contact Lens Care Apr 23, 2018 Solar Eclipse Inflicts Damage in the Shape of the ... edging closer, thanks to a wave of new technologies aiming to fix failing eye parts with human- ...

  16. Colored Contact Lens Dangers

    Medline Plus

    Full Text Available ... glow-in-the-dark lizard lenses, costume contacts can certainly add a spooky, eye-popping touch. But ... consideration as a standard contact lens because they can be purchased over-the-counter or on the ...

  17. Colored Contact Lens Dangers

    Medline Plus

    Full Text Available ... valid prescription that includes the brand name, lens measurements, and expiration date. Purchase the colored contact lenses ... with human-made versions. U.S. News Highlights the Value of Ophthalmologists APR 20, 2018 By Dan T. ...

  18. Vortex gas lens

    Science.gov (United States)

    Bogdanoff, David W.; Berschauer, Andrew; Parker, Timothy W.; Vickers, Jesse E.

    1989-01-01

    A vortex gas lens concept is presented. Such a lens has a potential power density capability of 10 to the 9th - 10 to the 10th w/sq cm. An experimental prototype was constructed, and the divergence half angle of the exiting beam was measured as a function of the lens operating parameters. Reasonably good agreement is found between the experimental results and theoretical calculations. The expanded beam was observed to be steady, and no strong, potentially beam-degrading jets were found to issue from the ends of the lens. Estimates of random beam deflection angles to be expected due to boundary layer noise are presented; these angles are very small.

  19. Colored Contact Lens Dangers

    Medline Plus

    Full Text Available ... had not been properly fitted by an eye care professional, the lenses stuck to my eye like ... lenses do not require the same level of care or consideration as a standard contact lens because ...

  20. Colored Contact Lens Dangers

    Medline Plus

    Full Text Available ... not require the same level of care or consideration as a standard contact lens because they can ... sell contacts without a prescription are breaking the law, and may be fined $11,000 per violation. " ...

  1. Colored Contact Lens Dangers

    Medline Plus

    Full Text Available ... not require the same level of care or consideration as a standard contact lens because they can ... Us About the Academy Jobs at the Academy Financial Relationships with Industry Medical Disclaimer Privacy Policy Terms ...

  2. Colored Contact Lens Dangers

    Medline Plus

    Full Text Available ... be purchased over-the-counter or on the Internet," says Thomas Steinemann, MD, professor of ophthalmology at ... ask for a prescription. There is no such thing as a "one size fits all" contact lens. ...

  3. Colored Contact Lens Dangers

    Medline Plus

    Full Text Available ... prescription. Follow the contact lens care directions for cleaning, disinfecting, and wearing the lenses. Never share contact ... with Industry Medical Disclaimer Privacy Policy Terms of Service For Advertisers For Media Ophthalmology Job Center © American ...

  4. Retrieving the thermal diffusivity and effusivity of solids from the same frequency scan using the front photopyroelectric technique

    International Nuclear Information System (INIS)

    Salazar, Agustín; Oleaga, Alberto; Mendioroz, Arantza; Apiñaniz, Estibaliz

    2017-01-01

    The photopyroelectric (PPE) technique in the front configuration consists in illuminating one surface of a pyroelectric slab while the other surface is in contact with the test sample. This method has been widely used to measure the thermal effusivity of liquids. Recently, it has been extended to measure the thermal effusivity of solids, by taking into account the influence of the coupling fluid layer used to guarantee the thermal contact. In both cases, the sample (liquid or solid) must be very thick. In this work, we propose a classical frequency scan of a thin sample slab to retrieve the thermal diffusivity and effusivity simultaneously. We use the amplitude and the phase of the front PPE signal, which depend on four parameters: the sample diffusivity and effusivity, the coupling fluid thickness and the coefficient of heat losses. It is demonstrated that the four quantities are not correlated. PPE measurements performed on a set of calibrated solids confirm the ability of the method to obtain the thermal diffusivity and effusivity of solids accurately. (paper)

  5. Optofluidic lens actuated by laser-induced solutocapillary forces

    Science.gov (United States)

    Malyuk, A. Yu.; Ivanova, N. A.

    2017-06-01

    We demonstrate an adaptive liquid lens controlled by laser-induced solutocapillary forces. The liquid droplet serving as a lens is formed in a thin layer of binary liquid mixture by surface tension driven flows caused by the thermal action of laser irradiation. The shape of droplet, its aperture and the focal length are reversibly changed without hysteresis by varying the intensity of the laser beam. The focal length variation range of the droplet-lens lies in between infinity (a flat layer) to 15 mm (a curved interface). The droplet-lens is capable to adjust the in-plane lateral position in response to a displacement of the laser beam. The proposed laser controlled droplet-lens will enable to develop smart liquid optical devices, which can imitate the accommodation reflex and pupillary light reflex of the eye.

  6. Improving thermal efficiency and increasing production rate in the double moving beds thermally coupled reactors by using differential evolution (DE) technique

    International Nuclear Information System (INIS)

    Karimi, Mohsen; Rahimpour, Mohammad Reza; Rafiei, Razieh; Shariati, Alireza; Iranshahi, Davood

    2016-01-01

    Highlights: • Double moving bed thermally coupled reactor is modeled in two dimensions. • The required heat of naphtha process is attained with nitrobenzene hydrogenation. • DE optimization method is applied to optimize operating conditions. • Hydrogen, aromatic and aniline productions increase in the proposed configuration. - Abstract: According to the global requirements for energy saving and the control of global warming, multifunctional auto-thermal reactors as a novel concept in the process integration (PI) have risen up in the recent years. In the novel modification presented in this study, the required heat of endothermic naphtha reforming process has been supplied by nitrobenzene hydrogenation reaction. In addition, the enhancement of reactor performance, such as the increase of production rate, has become a key issue in the diverse industries. Thus, Differential Evolution (DE) technique is applied to optimize the operating conditions (temperature and pressure) and designing parameters of a thermally coupled reactor with double moving beds. Ultimately, the obtained results of the proposed model are compared with non-optimized and conventional model. This model results in noticeable reduction in the operational costs as well as enhancement of the net profit of the plant. The increase in the hydrogen and aromatic production shows the superiority of the proposed model.

  7. Remotely controlled cutting techniques in the field of nuclear decommissioning. Overview of effectively applied thermal and non thermal cutting methods

    International Nuclear Information System (INIS)

    Bienia, H.

    2008-01-01

    Remote disassembly of radiologically burdened large components is among the most sophisticated and complex activities in the dismantling of nuclear installations. The required space for the technical equipment during the dismantling operations, especially for the removal of larger components is often an additional problem. Conventional cutting technologies like sawing with a disk saw or band saw require large and heavy frameworks as well as guiding systems with high rigidity. These solutions are expensive and sometimes not applicable. The essential question of all cutting and dismantling tasks is the physiological constitution of the component which will be dismantled. That means size, material and structure of the component. All these points are primarily technological questions. The last question is about the estimated costs of the used dismantling technology. Therefore following questions must be answered. How much are the investments for the cutting equipment itself and how much are the investments for the supporting equipment (e.g. necessary handling equipment)? Can I use this cutting equipment only for one special task or is it applicable for many tasks and therefore saves money because other cutting or dismantling technologies are dispensable? How long is the cutting time and what is the to control this technique required personnel? Four different cutting and dismantling technologies will be introduced and described. These four technologies differ in their principle of operation but all of them are used by cutting and dismantling tasks in nuclear power plants. (author)

  8. Vitrectorhexis and lens aspiration with posterior chamber intraocular lens implantation in spherophakia.

    Science.gov (United States)

    Al-Haddad, Christiane; Khatib, Lama

    2012-07-01

    We describe a technique that uses the vitrector to perform successful lens aspiration and posterior chamber intraocular lens (IOL) implantation in children with spherophakia and anterior lens subluxation. After an anterior chamber maintainer is placed, the ocutome is introduced through a limbal incision to perform a circular vitrectorhexis to avoid excessive manipulation of the unstable lens followed by gentle cortex aspiration. A foldable IOL is injected into the sulcus (3-piece IOL) or bag (1-piece IOL) if the capsule is sufficiently stable. Through a pars plana incision, the ocutome is then used to perform a posterior capsulotomy to prevent late posterior capsule opacification. In our patient, sulcus IOL placement was more stable than in-the-bag placement. Neither author has a financial or proprietary interest in any material or method mentioned. Copyright © 2012 ASCRS and ESCRS. Published by Elsevier Inc. All rights reserved.

  9. Isotopic Determination of Nuclear Materials Using Nuclear Fission Track Registration Technique and Thermal Ionization Mass Spectrometric Technique

    International Nuclear Information System (INIS)

    Jeon, Young Sin; Pyo, Hyeong Yeol; Park, Yong Joon; Song, Kyu Seok; Kim, Won Ho; Jee, Kwang Yong

    2007-05-01

    It is very important to develope the technology for the determination of isotopic ratios of hot particles( 234 U, 235 U, 236 U etc.) detected from swipe samples of various nuclear facilities. This technology is highly competitive internationally and has to be established independently as long as our government maintains atomic energy and treats nuclear materials. In this text, sample pretreatment procedure, gamma-ray counting, alpha or fission track techniques, isotopic analysis of U and Pu, background problems and detection limits for mass determination, and their application to the real swipe sample were described with detailed procedure. This technology would contribute to the Korean economy's high growth rate as well as to superiority of government's leading research and development programs if successfully established

  10. Vapor-cooled lead and stacks thermal performance and design analysis by finite difference techniques

    International Nuclear Information System (INIS)

    Peck, S.D.; Christensen, E.H.; O'Loughlin, J.M.

    1985-01-01

    Investigation of the combined thermal performance of the stacks and vapor cooled leads for the Mirror Fusion Test Facility-''B'' demonstrates considerable interdependency. For instance, the heat transfer to the vapor-cooled lead (VCL) from warm bus heaters, environmental enclosure, and stack is a significant additional heat load to the joule heating in the leads, proportionately higher for the lower current leads that have fewer current-carrying, counter flow coolant copper tubes. Consequently, the specific coolant flow (G/sec-kA-lead pair) increases as the lead current decreases. The definition of this interdependency and the definition of necessary thermal management has required an integrated thermal model for the entire stack/VCL assemblies

  11. State of affairs on pollutants and syngas removal techniques stemming from thermal treatment of waste by gasification. Extended abstract

    International Nuclear Information System (INIS)

    Megret, O.; Bequet, L.

    2011-10-01

    The aim of the current study is to outline the state of affairs related to pollutants and slaughtering techniques of syngas that result both from waste thermal treatment by gasification. The study starts by a review permitting to classify the gasification techniques applied to waste thermal treatment. This review leads to distinguish between auto-thermal and allo-thermal equipments. Furthermore, are described, in this first part, the general principles and parameters of functioning and adjustment of the factors characterizing the thermal treatment in reducing atmosphere. It is also about the composition of the syngas products according to the different driving behaviours of gasifiers. Finally, we state succinctly, on one hand, the possible promotion procedures in the frame of syngas development and, on the other hand, the thresholds that we ought to reach in order to make this promotion achievable. The second part of the study deals with the characteristics of the pollutants located in the syngas. This description took the shape of a detailed index card where pollutants are classified into minority components (including those of pollutants, those of gaseous and those of particulates) according to their concentrations, to their driving behaviours and to their thermochemical conditions of formation (temperature, pressure, response-type agents, atmosphere...). In the last part, we discuss the current and the considered types of slaughtering devices in reducing atmosphere in relation with their performance in slaughtering and regarding the departure point of syngas promotion ways. Finally, are exposed the key postures and the barricades within those technologies. Hereupon, research axes are proposed. (authors)

  12. An intelligent approach for cooling radiator fault diagnosis based on infrared thermal image processing technique

    International Nuclear Information System (INIS)

    Taheri-Garavand, Amin; Ahmadi, Hojjat; Omid, Mahmoud; Mohtasebi, Seyed Saeid; Mollazade, Kaveh; Russell Smith, Alan John; Carlomagno, Giovanni Maria

    2015-01-01

    This research presents a new intelligent fault diagnosis and condition monitoring system for classification of different conditions of cooling radiator using infrared thermal images. The system was adopted to classify six types of cooling radiator faults; radiator tubes blockage, radiator fins blockage, loose connection between fins and tubes, radiator door failure, coolant leakage, and normal conditions. The proposed system consists of several distinct procedures including thermal image acquisition, image pre-processing, image processing, two-dimensional discrete wavelet transform (2D-DWT), feature extraction, feature selection using a genetic algorithm (GA), and finally classification by artificial neural networks (ANNs). The 2D-DWT is implemented to decompose the thermal images. Subsequently, statistical texture features are extracted from the original images and are decomposed into thermal images. The significant selected features are used to enhance the performance of the designed ANN classifier for the 6 types of cooling radiator conditions (output layer) in the next stage. For the tested system, the input layer consisted of 16 neurons based on the feature selection operation. The best performance of ANN was obtained with a 16-6-6 topology. The classification results demonstrated that this system can be employed satisfactorily as an intelligent condition monitoring and fault diagnosis for a class of cooling radiator. - Highlights: • Intelligent fault diagnosis of cooling radiator using thermal image processing. • Thermal image processing in a multiscale representation structure by 2D-DWT. • Selection features based on a hybrid system that uses both GA and ANN. • Application of ANN as classifier. • Classification accuracy of fault detection up to 93.83%

  13. In Situ Determination of Thermal Profiles during Czochralski Silicon Crystal Growth by an Eddy Current Technique.

    Science.gov (United States)

    Choe, Kwang Su.

    An eddy current testing method was developed to continuously monitor crystal growth process and determine thermal profiles in situ during Czochralski silicon crystal growth. The work was motivated by the need to improve the quality of the crystal by controlling thermal gradients and annealing history over the growth cycle. The experimental concept is to monitor intrinsic electrical conductivities of the growing crystal and deduce temperature values from them. The experiments were performed in a resistance-heated Czochralski puller with a 203 mm (8 inch) diameter crucible containing 6.5 kg melt. The silicon crystals being grown were about 80 mm in diameter and monitored by an encircling sensor operating at three different test frequencies (86, 53 and 19 kHz). A one-dimensional analytical solution was employed to translate the detected signals into electrical conductivities. In terms of experiments, the effects of changes in growth condition, which is defined by crystal and crucible rotation rates, crucible position, pull rate, and hot-zone configuration, were investigated. Under a given steady-state condition, the thermal profile was usually stable over the entire length of crystal growth. The profile shifted significantly, however, when the crucible rotation rate was kept too high. As a direct evidence to the effects of melt flow on heat transfer process, a thermal gradient minimum was observed about the crystal/crucible rotation combination of 20/-10 rpm cw. The thermal gradient reduction was still most pronounced when the pull rate or the radiant heat loss to the environment was decreased: a nearly flat axial thermal gradient was achieved when either the pull rate was halved or the height of the exposed crucible wall was effectively doubled. Under these conditions, the average axial thermal gradient along the surface of the crystal was about 4-5 ^{rm o}C/mm. Regardless of growth condition, the three-frequency data revealed radial thermal gradients much larger

  14. Thermal diffusivity of a metallic thin layer using the time-domain thermo reflectance technique

    International Nuclear Information System (INIS)

    Battaglia, J-L; Kusiak, A; Rossignol, C; Chigarev, N

    2007-01-01

    The time domain thermo reflectance (TDTR) is widely used in the field of acoustic and thermal characterization of thin layers at the nano and micro scale. In this paper, we propose to derive a simple analytical expression of the thermal diffusivity of the layer. This relation is based on the analytical solution of one-dimensional heat transfer in the medium using integral transforms. For metals, the two-temperature model shows that the capacitance effect at the short times is essentially governed by the electronic contribution

  15. Evaluation of lens dose in medulloblastoma radiotherapy

    International Nuclear Information System (INIS)

    Oliveira, F.L.; Vilela, E.C.; Sousa, S.A; Lima, F.F. de

    2007-01-01

    The improvement of the applied radiotherapy techniques in the cranial-spinal therapy, which is used in the cases of medulloblastoma, aims the reduction of the risks of future damages in enclosed critical agencies in the irradiation fields. This work aims to evaluate the lens doses due two common techniques used in medulloblastoma radiotherapy. For this, thermoluminescent dosimeters, previously calibrated, were located in an anthropomorphic phantom (ALDERSON - RANDON Laboratory), in the tumor and lens positions. The employed techniques were as following: (1) angled fields technique and (2) half-beam block technique. The phantom was irradiated five times in each technique with two lateral opposed fields in the brain with a total prescribed dose of 1.5 Gy, followed of two posterior spinal fields with the same prescribed dose, using a 6MV accelerator. The results showed that the doses in the first technique were 0.10 +- 0,04 Gy and, in second one, 0.09 +- 0,02 Gy. It was observed that, independent of the employed technique, the lens doses practically are the same. (author)

  16. Efficient cycle jumping techniques for the modelling of materials and structures under cyclic mechanical and thermal loading

    International Nuclear Information System (INIS)

    Dunne, F.P.E.; Hayhurst, D.R.

    1994-01-01

    Highly efficient cycle jumping algorithms have been developed for the calculation of stress and damage histories for both cyclic mechanical and cycle thermal loading. The techniques have been shown to be suitable for cyclic plasticity; creep-cyclic plasticity interaction; and creep dominated material behaviour. The cycle jumping algorithms have been validated by comparison of the predictions made using both the cycle jumping technique, and the full calculation involving the integration of the equations around all cycles. Excellent agreement has been achieved, and significant reductions in computer processing time of up to 90% have been obtained by using the cycle jumping technique. A further cycle jumping technique has been developed for full component analysis, using a viscoplastic damage finite element solver, which enables stress redistribution to be modelled. The behaviour and lifetime of a slag tap component has been predicted when subjected to cyclic thermal loading. Cyclic plasticity damage and micro-crack initiation is predicted to occur at the water cooling duct after 2.974 cycles, with damage and micro-crack evolution arresting after 60.000. (author). 18 refs., 13 figs., 4 photos

  17. Near-field microscopy with a microfabricated solid immersion lens

    Science.gov (United States)

    Fletcher, Daniel Alden

    2001-07-01

    Diffraction of focused light prevents optical microscopes from resolving features in air smaller than half the wavelength, λ Spatial resolution can be improved by passing light through a sub-wavelength metal aperture scanned close to a sample, but aperture-based probes suffer from low optical throughput, typically below 10-4. An alternate and more efficient technique is solid immersion microscopy in which light is focused through a high refractive index Solid Immersion Lens (SIL). This work describes the fabrication, modeling, and use of a microfabricated SIL to obtain spatial resolution better than the diffraction limit in air with high optical throughput for infrared applications. SILs on the order of 10 μm in diameter are fabricated from single-crystal silicon and integrated onto silicon cantilevers with tips for scanning. We measure a focused spot size of λ/5 with optical throughput better than 10-1 at a wavelength of λ = 9.3 μm. Spatial resolution is improved to λ/10 with metal apertures fabricated directly on the tip of the silicon SIL. Microlenses have reduced spherical aberration and better transparency than large lenses but cannot be made arbitrarily small and still focus. We model the advantages and limitations of focusing in lenses close to the wavelength in diameter using an extension of Mie theory. We also investigate a new contrast mechanism unique to microlenses resulting from the decrease in field-of-view with lens diameter. This technique is shown to achieve λ/4 spatial resolution. We explore applications of the microfabricated silicon SIL for high spatial resolution thermal microscopy and biological spectroscopy. Thermal radiation is collected through the SIL from a heated surface with spatial resolution four times better than that of a diffraction- limited infrared microscope. Using a Fourier-transform infrared spectrometer, we observe absorption peaks in bacteria cells positioned at the focus of the silicon SIL.

  18. Determination of thermal characteristics of standard and improved hollow concrete blocks using different measurement techniques

    DEFF Research Database (Denmark)

    Caruana, C.; Yousif, C.; Bacher, Peder

    2017-01-01

    The lighter weight, improved thermal properties and better acoustic insulation of hollow-core concrete blocks are few of the characteristics that one encounters when comparing them to traditional Maltese globigerina limestone solid blocks. As a result, hollow concrete blocks have recently been...

  19. Robust Optimization of Thermal Aspects of Friction Stir Welding Using Manifold Mapping Techniques

    DEFF Research Database (Denmark)

    Larsen, Anders Astrup; Lahaye, Domenico; Schmidt, Henrik Nikolaj Blicher

    2008-01-01

    The aim of this paper is to optimize a friction stir welding process taking robustness into account. The optimization problems are formulated with the goal of obtaining desired mean responses while reducing the variance of the response. We restrict ourselves to a thermal model of the process...

  20. A Data Analysis Technique to Estimate the Thermal Characteristics of a House

    NARCIS (Netherlands)

    Tabatabaei, S.; van der Ham, Wim; Klein, Michel C. A.; Treur, Jan

    2017-01-01

    Almost one third of the energy is used in the residential sector, and space heating is the largest part of energy consumption in our houses. Knowledge about the thermal characteristics of a house can increase the awareness of homeowners about the options to save energy, for example by showing that

  1. Utilizing the slowing-down-time technique for benchmarking neutron thermalization in graphite

    International Nuclear Information System (INIS)

    Zhou, T.; Hawari, A. I.; Wehring, B. W.

    2007-01-01

    Graphite is the moderator/reflector in the Very High Temperature Reactor (VHTR) concept of Generation IV reactors. As a thermal reactor, the prediction of the thermal neutron spectrum in the VHTR is directly dependent on the accuracy of the thermal neutron scattering libraries of graphite. In recent years, work has been on-going to benchmark and validate neutron thermalization in 'reactor grade' graphite. Monte Carlo simulations using the MCNP5 code were used to design a pulsed neutron slowing-down-time experiment and to investigate neutron slowing down and thermalization in graphite at temperatures relevant to VHTR operation. The unique aspect of this experiment is its ability to observe the behavior of neutrons throughout an energy range extending from the source energy to energies below 0.1 eV. In its current form, the experiment is designed and implemented at the Oak Ridge Electron Linear Accelerator (ORELA). Consequently, ORELA neutron pulses are injected into a 70 cm x 70 cm x 70 cm graphite pile. A furnace system that surrounds the pile and is capable of heating the graphite to a centerline temperature of 1200 K has been designed and built. A system based on U-235 fission chambers and Li-6 scintillation detectors surrounds the pile. This system is coupled to multichannel scaling instrumentation and is designed for the detection of leakage neutrons as a function of the slowing-down-time (i.e., time after the pulse). To ensure the accuracy of the experiment, careful assessment was performed of the impact of background noise (due to room return neutrons) and pulse-to-pulse overlap on the measurement. Therefore, the entire setup is surrounded by borated polyethylene shields and the experiment is performed using a source pulse frequency of nearly 130 Hz. As the basis for the benchmark, the calculated time dependent reaction rates in the detectors (using the MCNP code and its associated ENDF-B/VI thermal neutron scattering libraries) are compared to measured

  2. Measurement of the thermal diffusivity and speed of sound of hydrothermal solutions via the laser-induced grating technique

    International Nuclear Information System (INIS)

    Butenhoff, T.J.

    1994-01-01

    Hydrothermal processing is being developed as a method for organic destruction for the Hanford Site in Washington. Hydrothermal processing refers to the redox reactions of chemical compounds in supercritical or near-supercritical aqueous solutions. In order to design reactors for the hydrothermal treatment of complicated mixtures found in the Hanford wastes, engineers need to know the thermophysical properties of the solutions under hydrothermal conditions. The author used the laser-induced grating technique to measure the thermal diffusivity and speed of sound of hydrothermal solutions. In this non-invasive optical technique, a transient grating is produced in the hydrothermal solution by optical absorption from two crossed time-coincident nanosecond laser pulses. The grating is probed by measuring the diffraction efficiency of a third laser beam. The grating relaxes via thermal diffusion, and the thermal diffusivity can be determined by measuring the decay of the grating diffraction efficiency as a function of the pump-probe delay time. In addition, intense pump pulses produce counterpropagating acoustic waves that appear as large undulations in the transient grating decay spectrum. The speed of sound in the sample is simply the grating fringe spacing divided by the undulation period. The cell is made from a commercial high pressure fitting and is equipped with two diamond windows for optical access. Results are presented for dilute dye/water solutions with T = 400 C and pressures between 20 and 70 MPa

  3. One-step fabrication of submicrostructures by low one-photon absorption direct laser writing technique with local thermal effect

    Science.gov (United States)

    Nguyen, Dam Thuy Trang; Tong, Quang Cong; Ledoux-Rak, Isabelle; Lai, Ngoc Diep

    2016-01-01

    In this work, local thermal effect induced by a continuous-wave laser has been investigated and exploited to optimize the low one-photon absorption (LOPA) direct laser writing (DLW) technique for fabrication of polymer-based microstructures. It was demonstrated that the temperature of excited SU8 photoresist at the focusing area increases to above 100 °C due to high excitation intensity and becomes stable at that temperature thanks to the use of a continuous-wave laser at 532 nm-wavelength. This optically induced thermal effect immediately completes the crosslinking process at the photopolymerized region, allowing obtain desired structures without using the conventional post-exposure bake (PEB) step, which is usually realized after the exposure. Theoretical calculation of the temperature distribution induced by local optical excitation using finite element method confirmed the experimental results. LOPA-based DLW technique combined with optically induced thermal effect (local PEB) shows great advantages over the traditional PEB, such as simple, short fabrication time, high resolution. In particular, it allowed the overcoming of the accumulation effect inherently existed in optical lithography by one-photon absorption process, resulting in small and uniform structures with very short lattice constant.

  4. 3D Inkjet Printed Helical Antenna with Integrated Lens

    KAUST Repository

    Farooqui, Muhammad Fahad; Shamim, Atif

    2016-01-01

    The gain of an antenna can be enhanced through the integration of a lens, although this technique has traditionally been restricted to planar antennas due to fabrication limitations of standard manufacturing processes. Here, through a unique

  5. Primary intraocular lens implantation for penetrating lens trauma in Africa.

    Science.gov (United States)

    Bowman, R J; Yorston, D; Wood, M; Gilbert, C; Foster, A

    1998-09-01

    This study aimed to audit the surgical strategy of primary posterior chamber intraocular lens implantation for cases of recent penetrating trauma involving the lens in an African population. Retrospective, noncomparative case series. Seventy-two cases are reported, including all patients who underwent primary intraocular lens implantation for traumatic cataract extraction performed within 1 month of injury between 1988 and 1996. Demographic characteristics and follow-up attendance rates are analyzed. Surgical technique and the occurrence of intraoperative and postoperative complications are reported. Visual outcomes are reported with detailed analysis for cases of poor visual outcome. Mean age was 14.3 years (standard deviation = 11.1), 57 (79%) were male and 15 (21%) were female (chi-square = 23.66, P capsule had been breached by the trauma in 27 (38%) cases, and 15 of these required anterior vitrectomy. Capsular fixation of the implant was achieved in 49% of patients, the remainder having sulcus fixation. Intraoperative rupture of the posterior capsule occurred in four cases. The only common postoperative complication was acute fibrinous anterior uveitis, which occurred in 29 (40%) patients, and 32% of patients followed up for at least 6 months required secondary posterior capsulotomy. This was more common in younger patients (chi-square = 4.2, P < 0.05). Corrected postoperative visual acuities were available for 51 patients, of which 71% achieved 20/60 or better visual acuity. Patients 6 years of age or younger were less likely to achieve 20/60 (chi-square = 6.61, P = 0.01). This surgical strategy has proved successful, producing good visual results and causing no sight-threatening complications. Primary posterior capsulotomy may be appropriate for younger patients.

  6. 3D printed helical antenna with lens

    KAUST Repository

    Farooqui, Muhammad Fahad

    2016-12-19

    The gain of an antenna can be enhanced through the integration of a lens, however this technique has traditionally been restricted to planar antennas due to fabrication limitations of standard manufacturing processes. Here, with a unique combination of 3D and 2D inkjet printing of dielectric and metallic inks respectively, we demonstrate a Fresnel lens that has been monolithically integrated to a non-planar antenna (helix) for the first time. Antenna measurements show that the integration of a Fresnel lens enhances the gain of a 2-turn helix by around 4.6 dB giving a peak gain of about 12.9 dBi at 8.8 GHz.

  7. High quality aluminide and thermal barrier coatings deposition for new and service exposed parts by CVD techniques

    Energy Technology Data Exchange (ETDEWEB)

    Pedraza, F.; Tuohy, C.; Whelan, L.; Kennedy, A.D. [SIFCO Turbine Components, Carrigtwohill, Cork (Ireland)

    2004-07-01

    In this work, the performance of CVD aluminide coatings is compared to that of coatings deposited by the classical pack cementation technique using standard SIFCO procedures. The CVD coatings always seem to behave better upon exposure to isothermal and cyclic oxidation conditions. This is explained by a longer term stability of CVD coatings, with higher Al amounts in the diffusion zone and less refractory element precipitation in the additive layer. The qualities of Pt/Al coatings by out-of-pack and CVD are also compared as a previous step for further thermal barrier coating deposition. As an example, YSZ thermal barrier coatings are deposited by MO-CVD on Pt/Al CVD bond coats rendering adherent and thick coatings around the surface of turbine blades. This process under development does not require complex manipulation of the component to be coated. (orig.)

  8. Man-made vitreous fiber produced from incinerator ash using the thermal plasma technique and application as reinforcement in concrete.

    Science.gov (United States)

    Yang, Sheng-Fu; Wang, To-Mai; Lee, Wen-Cheng; Sun, Kin-Seng; Tzeng, Chin-Ching

    2010-10-15

    This study proposes using thermal plasma technology to treat municipal solid waste incinerator ashes. A feasible fiberization method was developed and applied to produce man-made vitreous fiber (MMVF) from plasma vitrified slag. MMVF were obtained through directly blending the oxide melt stream with high velocity compressed air. The basic technological characteristics of MMVF, including morphology, diameter, shot content, length and chemical resistance, are described in this work. Laboratory experiments were conducted on the fiber-reinforced concrete. The effects of fibrous content on compressive strength and flexural strength are presented. The experimental results showed the proper additive of MMVF in concrete can enhance its mechanical properties. MMVF products produced from incinerator ashes treated with the thermal plasma technique have great potential for reinforcement in concrete. 2010 Elsevier B.V. All rights reserved.

  9. Experimental determination of the thermal contact conductance between two solid surfaces by the energy pulse technique

    International Nuclear Information System (INIS)

    Rubin, Gerson Antonio

    1979-01-01

    An experimental procedure for the determination of the thermal contact conductance between two solid surfaces as a function of the contact pressure and the energy of the laser radiation has been developed using the laser pulse method. A rubi laser with variable energy levels was employed as a radiating pulse energy source. The laser beam was allowed to impinge perpendicularly on the front face of a electrolytic iron 73 4 . The temperature fluctuations resulting on the back surface of the sample was detected by a thermocouple, which Is coupled to a PDP-11/45 Computer 32 Kbytes of memory, through a Analog-Digital Converter. A theoretical function, derived exclusively for the problem mentioned in this work, was adjusted by a method of least square fitting of experimental results. This adjustment yielded the value of a parameter related to the contact conductance between two surfaces. The experimental error obtained for the thermal contact conductance was +- 4.9%. (author)

  10. [Congenital lens subluxation: visual acuity outcomes and intraocular lens postoperative position].

    Science.gov (United States)

    Arraes, Caroline; Endriss, Daniela; Lobato, Francisco; Arraes, João; Ventura, Marcelo

    2010-01-01

    To evaluate the visual acuity outcomes and to investigate the intraocular lens (IOL) and endocapsular ring positions with ultrasound biomicroscopy in 17 eyes of 10 patients with congenital lens subluxation who underwent the same surgical technique, by the same surgeon. The study was performed in the ''Hospital de Olhos de Pernambuco'' and ''Fundação Altino Ventura''. The surgical technique consisted of phacoaspiration with implant of endocapsular ring and intraocular lens with one loop haptic amputated. The age varied from 7 to 22 years. Data on visual acuity (VA) before and after surgery, surgery follow-up period, and complications were analyzed. All patients underwent ultrasound biomicroscopy. The mean follow-up period was 2.8 years. There was a VA improvement in 17 (100%) eyes: in 12 eyes (70.6%) the visual acuity was better than 20/40; 4 (23.5%) ranged from 20/40 to 20/100, and 1 (5.9%) had visual acuity worse than 20/100, however better than the preoperative visual acuity. The posterior capsular opacification occurred in 10 eyes (58.9%). Ultrasound biomicroscopy showed that all IOL were partially decentralized, however without surpassing the pupil border limit. Endocapsular ring position was correct and there was a good capsular support in all cases. The evaluated surgical treatment provided good intraocular lens and endocapsular ring position, with VA improvement Thus, this technique is a viable, effective and safe option for the visual rehabilitation of patients with congenital lens subluxation.

  11. Coupled neutronic-thermal-hydraulics analysis in a coolant subchannel of a PWR using CFD techniques

    Energy Technology Data Exchange (ETDEWEB)

    Ribeiro, Felipe P.; Su, Jian, E-mail: sujian@nuclear.ufrj.br [Coordenacao de Pos-Graduacao e Pesquisa de Engenharia (COPPE/UFRJ), Rio de Janeiro, RJ (Brazil). Programa de Engenharia Nuclear

    2017-07-01

    The high capacity of Computational Fluid Dynamics code to predict multi-dimensional thermal-hydraulics behaviour and the increased availability of capable computer systems are making that method a good tool to simulate phenomena of thermal-hydraulics nature in nuclear reactors. However, since there are no neutron kinetics models available in commercial CFD codes to the present day, the application of CFD in the nuclear reactor safety analyses is still limited. The present work proposes the implementation of the point kinetics model (PKM) in ANSYS - Fluent to predict the neutronic behaviour in a Westinghouse Sequoyah nuclear reactor, coupling with the phenomena of heat conduction in the rod and thermal-hydraulics in the cooling fluid, via the reactivity feedback. Firstly, a mesh convergence and turbulence model study was performed, using the Reynolds-Average Navier-Stokes method, with square arrayed rod bundle featuring pitch to diameter ratio of 1:32. Secondly, simulations using the k-! SST turbulence model were performed with an axial distribution of the power generation in the fuel to analyse the heat transfer through the gap and cladding, and its in fluence on the thermal-hydraulics behaviour of the cooling fluid. The wall shear stress distribution for the centre-line rods and the dimensionless velocity were evaluated to validate the model, as well as the in fluence of the mass flow rate variation on the friction factor. The coupled model enabled to perform a dynamic analysis of the nuclear reactor during events of insertion of reactivity and shutdown of primary coolant pumps. (author)

  12. Passive Solar Techniques to Improve Thermal Comfort and Reduce Energy Consumption of Domestic Use

    OpenAIRE

    Naci Kalkan; Ihsan Dagtekin

    2016-01-01

    Passive design responds to improve indoor thermal comfort and minimize the energy consumption. The present research analyzed the how efficiently passive solar technologies generate heating and cooling and provide the system integration for domestic applications. In addition to this, the aim of this study is to increase the efficiency of solar systems system with integration some innovation and optimization. As a result, outputs of the project might start a new sector to provide environmentall...

  13. Positron mobility in thermally grown SiO2 measured by Doppler broadening technique

    International Nuclear Information System (INIS)

    Kong, Y.; Leung, T.C.; Asoka-Kumar, P.; Nielsen, B.; Lynn, K.G.

    1991-01-01

    The positron mobility in thermally grown SiO 2 is deduced from Doppler broadening lineshape data on a metal-oxide-semiconductor sample for positrons implanted into the oxide layer. The fitted mobility is ∼13(10)x10 -3 cm 2 /s V. This value is between that of the electron and hole mobilities in the same system and is two orders of magnitude smaller than the previous estimate from positron measurements

  14. Comparison of measured and predicted thermal mixing tests using improved finite difference technique

    International Nuclear Information System (INIS)

    Hassan, Y.A.; Rice, J.G.; Kim, J.H.

    1983-01-01

    The numerical diffusion introduced by the use of upwind formulations in the finite difference solution of the flow and energy equations for thermal mixing problems (cold water injection after small break LOCA in a PWR) was examined. The relative importance of numerical diffusion in the flow equations, compared to its effect on the energy equation was demonstrated. The flow field equations were solved using both first order accurate upwind, and second order accurate differencing schemes. The energy equation was treated using the conventional upwind and a mass weighted skew upwind scheme. Results presented for a simple test case showed that, for thermal mixing problems, the numerical diffusion was most significant in the energy equation. The numerical diffusion effect in the flow field equations was much less significant. A comparison of predictions using the skew upwind and the conventional upwind with experimental data from a two dimensional thermal mixing text are presented. The use of the skew upwind scheme showed a significant improvement in the accuracy of the steady state predicted temperatures. (orig./HP)

  15. A Data Analysis Technique to Estimate the Thermal Characteristics of a House

    Directory of Open Access Journals (Sweden)

    Seyed Amin Tabatabaei

    2017-09-01

    Full Text Available Almost one third of the energy is used in the residential sector, and space heating is the largest part of energy consumption in our houses. Knowledge about the thermal characteristics of a house can increase the awareness of homeowners about the options to save energy, for example by showing that there is room for improvement of the insulation level. However, calculating the exact value of these characteristics is not possible without precise thermal experiments. In this paper, we propose a method to automatically estimate two of the most important thermal characteristics of a house, i.e., the loss rate and the heat capacity, based on collected data about the temperature and gas usage. The method is evaluated with a data set that has been collected in a real-life case study. Although a ground truth is lacking, the analyses show that there is evidence that this method could provide a feasible way to estimate those values from the thermostat data. More detailed data about the houses in which the data was collected is required to draw stronger conclusions. We conclude that the proposed method is a promising way to add energy saving advice to smart thermostats.

  16. Development of process data capturing, analysis and controlling for thermal spray techniques - SprayTracker

    Science.gov (United States)

    Kelber, C.; Marke, S.; Trommler, U.; Rupprecht, C.; Weis, S.

    2017-03-01

    Thermal spraying processes are becoming increasingly important in high-technology areas, such as automotive engineering and medical technology. The method offers the advantage of a local layer application with different materials and high deposition rates. Challenges in the application of thermal spraying result from the complex interaction of different influencing variables, which can be attributed to the properties of different materials, operating equipment supply, electrical parameters, flow mechanics, plasma physics and automation. In addition, spraying systems are subject to constant wear. Due to the process specification and the high demands on the produced coatings, innovative quality assurance tools are necessary. A central aspect, which has not yet been considered, is the data management in relation to the present measured variables, in particular the spraying system, the handling system, working safety devices and additional measuring sensors. Both the recording of all process-characterizing variables, their linking and evaluation as well as the use of the data for the active process control presuppose a novel, innovative control system (hardware and software) that was to be developed within the scope of the research project. In addition, new measurement methods and sensors are to be developed and qualified in order to improve the process reliability of thermal spraying.

  17. Characterization of thermal, optical and carrier transport properties of porous silicon using the photoacoustic technique

    International Nuclear Information System (INIS)

    Sheng, Chan Kok; Mahmood Mat Yunus, W.; Yunus, Wan Md. Zin Wan; Abidin Talib, Zainal; Kassim, Anuar

    2008-01-01

    In this work, the porous silicon layer was prepared by the electrochemical anodization etching process on n-type and p-type silicon wafers. The formation of the porous layer has been identified by photoluminescence and SEM measurements. The optical absorption, energy gap, carrier transport and thermal properties of n-type and p-type porous silicon layers were investigated by analyzing the experimental data from photoacoustic measurements. The values of thermal diffusivity, energy gap and carrier transport properties have been found to be porosity-dependent. The energy band gap of n-type and p-type porous silicon layers was higher than the energy band gap obtained for silicon substrate (1.11 eV). In the range of porosity (50-76%) of the studies, our results found that the optical band-gap energy of p-type porous silicon (1.80-2.00 eV) was higher than that of the n-type porous silicon layer (1.70-1.86 eV). The thermal diffusivity value of the n-type porous layer was found to be higher than that of the p-type and both were observed to increase linearly with increasing layer porosity

  18. AlGaN/GaN MISHEMTs with AlN gate dielectric grown by thermal ALD technique.

    Science.gov (United States)

    Liu, Xiao-Yong; Zhao, Sheng-Xun; Zhang, Lin-Qing; Huang, Hong-Fan; Shi, Jin-Shan; Zhang, Chun-Min; Lu, Hong-Liang; Wang, Peng-Fei; Zhang, David Wei

    2015-01-01

    Recently, AlN plasma-enhanced atomic layer deposition (ALD) passivation technique had been proposed and investigated for suppressing the dynamic on-resistance degradation behavior of high-electron-mobility transistors (HEMTs). In this paper, a novel gate dielectric and passivation technique for GaN-on-Si AlGaN/GaN metal-insulator-semiconductor high-electron-mobility transistors (MISHEMTs) is presented. This technique features the AlN thin film grown by thermal ALD at 400°C without plasma enhancement. A 10.6-nm AlN thin film was grown upon the surface of the HEMT serving as the gate dielectric under the gate electrode and as the passivation layer in the access region at the same time. The MISHEMTs with thermal ALD AlN exhibit enhanced on/off ratio, reduced channel sheet resistance, reduction of gate leakage by three orders of magnitude at a bias of 4 V, reduced threshold voltage hysteresis of 60 mV, and suppressed current collapse degradation.

  19. Symmetric lens with extended depth of focus

    OpenAIRE

    Cho, Sung Nae

    2008-01-01

    The lens surface profile is derived based on the instantaneous focal length versus the lens radius data. The lens design based on instantaneous focal length versus the lens radius data has many useful applications in software assisted image focusing technology.

  20. A catoptric lens

    International Nuclear Information System (INIS)

    Rambauske, W.R.

    1973-01-01

    The invention relates to a catoptric lens for combining energies transmitted by several sources such as lasers; said lens comprising mirrors, the reflective surfaces of which have their focuses spaced from a common axis of symmetry. By means of these reflecting surfaces, which are generated by the nutation of portions of quadratic conics about the axis of symmetry, it is possible to focus the energy emmited by several lasers at the focus of the exit-mirror reflecting surface. This can be applied to thermonuclear fusion [fr

  1. Modern techniques for the emissions control in thermal electric stations; Tecnicas modernas para el control de emisiones en centrales termoelectricas

    Energy Technology Data Exchange (ETDEWEB)

    Romo Millares, C. A. [Instituto de Investigaciones Electricas, Cuernavaca (Mexico)

    1995-12-31

    This paper presents the techniques and the control equipment for emissions in thermal stations that have the highest possibilities of being considered in the immediate future in the national energy panorama and the established frame for the environmental normativity. The pollutant compounds subject to revision are the nitrogen and sulfur oxides and unburned particles. [Espanol] Se presentan las tecnicas y equipos de control de emisiones para centrales termoelectricas que tienen mayores posibilidades de ser consideradas en el futuro inmediato dentro del panorama energetico nacional y el marco establecido por la normatividad ambiental. Los compuestos contaminantes sujetos a revision son los oxidos de nitrogeno y azufre y las particulas inquemadas.

  2. Modern techniques for the emissions control in thermal electric stations; Tecnicas modernas para el control de emisiones en centrales termoelectricas

    Energy Technology Data Exchange (ETDEWEB)

    Romo Millares, C A [Instituto de Investigaciones Electricas, Cuernavaca (Mexico)

    1996-12-31

    This paper presents the techniques and the control equipment for emissions in thermal stations that have the highest possibilities of being considered in the immediate future in the national energy panorama and the established frame for the environmental normativity. The pollutant compounds subject to revision are the nitrogen and sulfur oxides and unburned particles. [Espanol] Se presentan las tecnicas y equipos de control de emisiones para centrales termoelectricas que tienen mayores posibilidades de ser consideradas en el futuro inmediato dentro del panorama energetico nacional y el marco establecido por la normatividad ambiental. Los compuestos contaminantes sujetos a revision son los oxidos de nitrogeno y azufre y las particulas inquemadas.

  3. Evaluating Origin of Electron Traps in Tris(8-hydroxyquinoline) Aluminum Thin Films using Thermally Stimulated Current Technique

    OpenAIRE

    Matsushima, Toshinori; Adachi, Chihaya

    2008-01-01

    We measured the energy distributions and concentrations of electron traps in O_2-unexposed and O_2-exposed tris(8-hydroxyquinoline) aluminum (Alq_3) films using a thermally stimulated current (TSC) technique to investigate how doping O_2 molecules in Alq_3 films affect the films' electron trap and electron transport characteristics. The results of our TSC studies revealed that Alq_3 films have an electron trap distribution with peak depths ranging from 0.075 to 0.1 eV and peak widths ranging ...

  4. Laser induced fluorescence thermometry (LIF-T) as a non-invasive temperature measurement technique for thermal hydraulic experiments

    Energy Technology Data Exchange (ETDEWEB)

    Strack, J.; Leung, K.; Walker, A., E-mail: strackj@mcmaster.ca [McMaster Univ., Hamilton, ON (Canada)

    2014-07-01

    Laser induced fluorescence (LIF) is an experimental technique whereby a scalar field in a fluid system is measured optically from the fluorescence intensity of a tracer dye following excitation by laser light. For laser induced fluorescence thermometry (LIF-T), a temperature sensitive dye is used. Through the use of a temperature sensitive tracer dye, sheet laser optics, optical filters, and photography, a 2D temperature field can be measured non-invasively. An experiment to test the viability of using LIF-T for macroscopic thermal hydraulic experiments was developed and tested. A reference calibration curve to relate fluorescence measurements to temperature is presented. (author)

  5. Thermal analysis of different application techniques on Nd:YAG laser after root canal preparation of single-rooted teeth

    International Nuclear Information System (INIS)

    Archilla, Jose Ricardo de F.

    2001-01-01

    The experiment objective is to analyze temperature variation, by means of three different application techniques of Nd:YAG laser in the root canals of singlerooted anterior teeth. Three root canals were instrumented, irrigated, X-rayed to measure the remaining dentin in the apical area and submitted to laser irradiation techniques used by Gutknecht, Matsumoto and a new technique with oscillatory movement. The used laser parameters were: pulse energy 250 mJ, frequency 5 Hz, pulse fluency 354 J/cm 2 , average potency 1,25 W, pulse width 300 μs, fiber core diameter 300 μs and interval of thermal relaxation of 20 s. After temperature evaluation and interpretation of the obtained data, it was concluded: 1) the oscillatory technique provided a better heat distribution during the laser application, when analyzing the graphs separately; 2) all the used techniques are within a pattern of safety, analyzing the average and highest temperatures of the apical area and the middle third, even so, disrespecting the last application day and the middle third of root 'C'.(author)

  6. A roadmap for photovoltaic-thermal panels. Combination of techniques offers many advantages

    International Nuclear Information System (INIS)

    Zondag, H.A.; Van Helden, W.G.J.; Bakker, M.

    2006-01-01

    In PVT technology, heat is extracted from PV cells. In this way, a device is made that produces both electricity and heat. In the EU funded coordination action PV-Catapult, workshops on PVT were organised at the PVSEC 2004 Conference in Paris and the Eurosun 2004 conference in Freiburg, to obtain active participation of the PV and solar thermal communities. Currently, the results of the workshops are used in the drafting of a roadmap for the large scale introduction of PVT technology on the market. First results will be presented here [nl

  7. Mercury speciation in environmental solid samples using thermal release technique with atomic absorption detection

    Energy Technology Data Exchange (ETDEWEB)

    Shuvaeva, Olga V. [Institute of Inorganic Chemistry, Academician Lavrent' ev Prospect 3, 630090 Novosbirsk (Russian Federation)], E-mail: olga@che.nsk.su; Gustaytis, Maria A.; Anoshin, Gennadii N. [Institute of Geology and Mineralogy, Siberian Branch of Russian Academy of Sciences, Koptyug Prospect 3, 630090 Novosibirsk (Russian Federation)

    2008-07-28

    A sensitive and very simple method for determination of mercury species in solid samples has been developed involving thermal release analysis in combination with atomic absorption (AAS) detection. The method allows determination of mercury(II) chloride, methylmercury and mercury sulfide at the level of 0.70, 0.35 and 0.20 ng with a reproducibility of the results of 14, 25 and 18%, respectively. The accuracy of the developed assay has been estimated using certified reference materials and by comparison of the results with those of an independent method. The method has been applied for Hg species determination in original samples of lake sediments and plankton.

  8. A Tribute to Len Barton

    Science.gov (United States)

    Tomlinson, Sally

    2010-01-01

    This article constitutes a short personal tribute to Len Barton in honour of his work and our collegial relationship going back over 30 years. It covers how Len saw his intellectual project of providing critical sociological and political perspectives on special education, disability and inclusion, and his own radical political perspectives. Len's…

  9. Application of sensitivity analysis to a simplified coupled neutronic thermal-hydraulics transient in a fast reactor using Adjoint techniques

    International Nuclear Information System (INIS)

    Gilli, L.; Lathouwers, D.; Kloosterman, J.L.; Van der Hagen, T.H.J.J.

    2011-01-01

    In this paper a method to perform sensitivity analysis for a simplified multi-physics problem is presented. The method is based on the Adjoint Sensitivity Analysis Procedure which is used to apply first order perturbation theory to linear and nonlinear problems using adjoint techniques. The multi-physics problem considered includes a neutronic, a thermo-kinetics, and a thermal-hydraulics part and it is used to model the time dependent behavior of a sodium cooled fast reactor. The adjoint procedure is applied to calculate the sensitivity coefficients with respect to the kinetic parameters of the problem for two reference transients using two different model responses, the results obtained are then compared with the values given by a direct sampling of the forward nonlinear problem. Our first results show that, thanks to modern numerical techniques, the procedure is relatively easy to implement and provides good estimation for most perturbations, making the method appealing for more detailed problems. (author)

  10. Thermal properties of biopolyol from oil palm fruit fibre (OPFF) using solvolysis liquefaction technique

    Science.gov (United States)

    Kormin, Shaharuddin; Rus, Anika Zafiah M.; Azahari, M. Shafiq M.

    2017-09-01

    Liquefaction is known to be an effective method for converting biomass into a biopolyol. The biomass liquefaction of oil palm fruit waste (PFW) in the presence of liquefaction solvent/polyhydric alcohol (PA): polyethylene glycol 400 (PEG400) using sulfuric acid as catalyst was studied. For all experiments, the liquefaction was conducted at 150°C and atmospheric pressure. The mass ratio of OPFW to liquefaction solvents used in all the experiments was, 1/3. Thermogravimetric analyses (TGA) were used to analyze their biopolyol and residue behaviors. It was found that thermal stability of oil palm mesocarp fibre (PM), oil palm shell (PS) and oil palm kernel (PK) fibre exhibited the first degradation of hard segment at (232, 104, 230°C) and the second degradation of soft segment at (314, 226, 412°C) as compared to PM, PS and PK residue which (229, 102, 227°C) of hard segment and (310, 219, 299°C) of segment, respectively. This behavior of thermal degradation of the hard segment and soft segment of biopolyol was changes after undergo solvolysis liquefaction process. The result analysis showed that the resulting biopolyol and its residue was suitable monomer for polyurethane (PU) synthesis for the production of PU foams.

  11. Thermal radiation analysis for small satellites with single-node model using techniques of equivalent linearization

    International Nuclear Information System (INIS)

    Anh, N.D.; Hieu, N.N.; Chung, P.N.; Anh, N.T.

    2016-01-01

    Highlights: • Linearization criteria are presented for a single-node model of satellite thermal. • A nonlinear algebraic system for linearization coefficients is obtained. • The temperature evolutions obtained from different methods are explored. • The temperature mean and amplitudes versus the heat capacity are discussed. • The dual criterion approach yields smaller errors than other approximate methods. - Abstract: In this paper, the method of equivalent linearization is extended to the thermal analysis of satellite using both conventional and dual criteria of linearization. These criteria are applied to a differential nonlinear equation of single-node model of the heat transfer of a small satellite in the Low Earth Orbit. A system of nonlinear algebraic equations for linearization coefficients is obtained in the closed form and then solved by the iteration method. The temperature evolution, average values and amplitudes versus the heat capacity obtained by various approaches including Runge–Kutta algorithm, conventional and dual criteria of equivalent linearization, and Grande's approach are compared together. Numerical results reveal that temperature responses obtained from the method of linearization and Grande's approach are quite close to those obtained from the Runge–Kutta method. The dual criterion yields smaller errors than those of the remaining methods when the nonlinearity of the system increases, namely, when the heat capacity varies in the range [1.0, 3.0] × 10 4  J K −1 .

  12. Equivalent Energy Density concept: A preliminary reexamination of a technique for equating thermal loads

    International Nuclear Information System (INIS)

    Ryder, E.E.

    1992-08-01

    Historical and projected inventories of spent fuel from commercial light-water nuclear reactors exhibit diverse decay characteristics and ages. This report summarizes a preliminary reexamination of a method for determining equivalent thermal loads for the range of spent fuel expected at a potential underground repository. The method, known at the Equivalent Energy Density (EED) concept, bases its equivalence criteria on the assumption that a given waste will produce worst-case thermomechanical effects equal to worst-case thermomechanical effects produced by a baseline waste, provided that the thermal energy deposited in the host rock over a specified deposition period is the same for both waste descriptions. To test this assumption, temperature histories at representative locations within the host rock were calculated using layouts defined by the EED concept and four deposition periods (20, 50, 100, and 300 years). It was found that the peak temperatures at near-field locations were best matched by the shorter deposition periods of 20 and 50 years. However, due to the sensitivity of the near-field environment to short-term canister-to-canister interactions, caution,should be used when choosing a near-field deposition period. At the location chosen to represent the far-field, a 300-year deposition period provided reasonable correspondence of peak temperature responses for all waste descriptions examined

  13. Investigation of the recycling of tires to elastomeric requirements by techniques of thermal compression

    Science.gov (United States)

    Nadal Gisbert, Antonio V.

    In this work is investigated the recycling of tires to elastomeric requirements by thermal compression. The production of recycled products is carried out starting from the powder, of elastomeric nature, coming from the grinding of used tires denominated GTR (Ground Tire Rubber) of different grain size, although the fundamental objective is the recycling of powder of 0,2mm grain size. The process of forming used for obtaining the recycled product is thermal compression, due to its simplicity and low cost. The composition of the powder has been analyzed and also the influence, on the elastomeric characteristics of the recycled product, of different parameters: Grain size, compact pressure, temperature, time, thickness of the recycled product and combination of sizes. At last we give an hypothesis that justifies the mechanism that gives cohesion to the powder GTR and allows their recycling. We also have carried out an analysis of the investigation lines, at the present, on the recycling of tires in general and an economic study of the viability of the recycled product in front of present products in the market, agglomerated with polyurethane, that have their application in using it in different types of floors.

  14. Colored Contact Lens Dangers

    Medline Plus

    Full Text Available ... prescription. There is no such thing as a "one size fits all" contact lens. Lenses that are not properly fitted may scratch the eye or cause blood vessels to grow into the cornea. Even if you have perfect vision, you need to get an eye exam and a prescription ...

  15. Contact Lens Risks

    Science.gov (United States)

    ... There is a risk of eye infection from bacteria in swimming pool water, hot tubs, lakes and the ocean Replace your contact lens storage case every 3 months or as directed by your eye care professional. Other Risks of Contact Lenses Other risks of contact lenses include pink eye ( ...

  16. MISSING: BUBBLE CHAMBER LENS

    CERN Multimedia

    2001-01-01

    Would the person who borrowed the large bubble chamber lens from the Microcosm workshops on the ISR please return it. This is a much used piece from our object archives. If anybody has any information about the whereabouts of this object, please contact Emma.Sanders@cern.ch Thank you

  17. The Lens of Chemistry

    Science.gov (United States)

    Thalos, Mariam

    2013-01-01

    Chemistry possesses a distinctive theoretical lens--a distinctive set of theoretical concerns regarding the dynamics and transformations of a perplexing variety of organic and nonorganic substances--to which it must be faithful. Even if it is true that chemical facts bear a special (reductive) relationship to physical facts, nonetheless it will…

  18. Colored Contact Lens Dangers

    Medline Plus

    Full Text Available ... wear any kind of contact lens. In Butler's case, the lenses caused an infection and left her with a corneal ... A recent article from U.S. News and World Report explains what ophthalmologists are and how they can ...

  19. Quadrupole magnetic lens

    International Nuclear Information System (INIS)

    Piskunov, V.A.

    1981-01-01

    The following connection of windings of electromagnet is suggested for simplification of the design of qUadrupole magnetic lens intended for use in radiotechnical and electron-optical devices. The mentioned windings are connected with each other by a bridge scheme and the variable resistors are switched in its diagonals in the lens containing four electromagnet with windings connected with two variable resistors the mobile contacts of which are connected with a direct current source. Current redistribution between left windings and right windings takes place at shift of mobile contact of variable resistor, and current redistribution between upper and low coils of electromagnets takes place at shifting mobile contact of the other variable resistor. In this case smooth and independent electron-optical misalignment of lens by two mutually perpendicular directions proceeds. Use of the given design of the lens in the oscillograph permits to use printing assembly for alignment plate and to reduce the number of connections at the expense of decreasing the number of resistors

  20. Colored Contact Lens Dangers

    Medline Plus

    Full Text Available ... can be purchased over-the-counter or on the Internet," says Thomas Steinemann, MD, professor of ophthalmology at ... ask for a prescription. There is no such thing as a "one size fits all" contact lens. Lenses that are not properly fitted may scratch the eye or cause blood vessels to grow into ...

  1. [Intraocular lens implantation with one loop haptic amputated: a new propose to the subluxation lens surgical treatment].

    Science.gov (United States)

    Ventura, Marcelo; Endriss, Daniela

    2010-01-01

    To evaluate the postoperative results of congenital lens subluxation corrected by a new technique. Retrospective chart review of 21 eyes of 13 patients with no traumatic lens subluxation who underwent surgery in Altino Ventura Foundation from April, 1999 to April, 2004. The mean age was 8.7 +/- 5.4 years old, and the mean follow-up period was 21.5 +/- 19.3 months. Patients underwent phacoaspiration, endocapsular ring and intraocular lens (IOL) implantation. The implanted IOL had one loop haptic excised and was supported above the ring, inside the capsular bag promoting intraocular lens centralization. Visual acuity improvement was observed in all cases. There was a significant reduction of the spherical equivalent and spherical component comparing the pre and postoperative refraction (psubluxation surgical treatment, promoting lens centralization and postoperative visual acuity improvement.

  2. Advance development of a technique for characterizing the thermomechanical properties of thermally stable polymers

    Science.gov (United States)

    Gillham, J. K.; Stadnicki, S. J.; Hazony, Y.

    1974-01-01

    The torsional braid experiment has been interfaced with a centralized hierarchical computing system for data acquisition and data processing. Such a system, when matched by the appropriate upgrading of the monitoring techniques, provides high resolution thermomechanical spectra of rigidity and damping, and their derivatives with respect to temperature.

  3. Variance-reduction technique for Coulomb-nuclear thermalization of energetic fusion products in hot plasmas

    International Nuclear Information System (INIS)

    DeVeaux, J.C.; Miley, G.H.

    1982-01-01

    A variance-reduction technique involving use of exponential transform and angular-biasing methods has been developed. Its purpose is to minimize the variance and computer time involved in estimating the mean fusion product (fp) energy deposited in a hot, multi-region plasma under the influence of small-energy transfer Coulomb collisions and large-energy transfer nuclear elastic scattering (NES) events. This technique is applicable to high-temperature D- 3 He, Cat. D and D-T plasmas which have highly energetic fps capable of undergoing NES. A first application of this technique is made to a D- 3 He Field Reversed Mirror (FRM) where the Larmor radius of the 14.7 MeV protons are typically comparable to the plasma radius (plasma radius approx. 2 fp gyroradii) and the optimistic fp confinement (approx. 45% of 14.7 MeV protons) previously predicted is vulnerable to large orbit perturbations induced by NES. In the FRM problem, this variance reduction technique is used to estimate the fractional difference in the average fp energy deposited in the closed-field region, E/sub cf/, with and without NES collisions

  4. An optimal guarding scheme for thermal conductivity measurement using a guarded cut-bar technique, part 1 experimental study

    International Nuclear Information System (INIS)

    Xing, Changhu

    2014-01-01

    In the guarded cut-bar technique, a guard surrounding the measured sample and reference (meter) bars is temperature controlled to carefully regulate heat losses from the sample and reference bars. Guarding is typically carried out by matching the temperature profiles between the guard and the test stack of sample and meter bars. Problems arise in matching the profiles, especially when the thermal conductivities of the meter bars and of the sample differ, as is usually the case. In a previous numerical study, the applied guarding condition (guard temperature profile) was found to be an important factor in measurement accuracy. Different from the linear-matched or isothermal schemes recommended in literature, the optimal guarding condition is dependent on the system geometry and thermal conductivity ratio of sample to meter bar. To validate the numerical results, an experimental study was performed to investigate the resulting error under different guarding conditions using stainless steel 304 as both the sample and meter bars. The optimal guarding condition was further verified on a certified reference material, pyroceram 9606, and 99.95% pure iron whose thermal conductivities are much smaller and much larger, respectively, than that of the stainless steel meter bars. Additionally, measurements are performed using three different inert gases to show the effect of the insulation effective thermal conductivity on measurement error, revealing low conductivity, argon gas, gives the lowest error sensitivity when deviating from the optimal condition. The result of this study provides a general guideline for the specific measurement method and for methods requiring optimal guarding or insulation

  5. Fracture resistance of metal-free composite crowns-effects of fiber reinforcement, thermal cycling, and cementation technique.

    Science.gov (United States)

    Lehmann, Franziska; Eickemeyer, Grit; Rammelsberg, Peter

    2004-09-01

    The improved mechanical properties of contemporary composites have resulted in their extensive use for the restoration of posterior teeth. However, the influence of fiber reinforcement, cementation technique, and physical stress on the fracture resistance of metal-free crowns is unknown. This in vitro study evaluated the effect of fiber reinforcement, physical stress, and cementation methods on the fracture resistance of posterior metal-free Sinfony crowns. Ninety-six extracted human third molars received a standardized tooth preparation: 0.5-mm chamfer preparation and occlusal reduction of 1.3 to 1.5 mm. Sinfony (nonreinforced crowns, n=48) and Sinfony-Vectris (reinforced crowns, n=48) crowns restoring original tooth contour were prepared. Twenty-four specimens of each crown type were cemented, using either glass ionomer cement (GIC) or resin cement. Thirty-two crowns (one third) were stored in humidity for 48 hours. Another third was exposed to 10,000 thermal cycles (TC) between 5 degrees C and 55 degrees C. The remaining third was treated with thermal cycling and mechanical loading (TCML), consisting of 1.2 million axial loads of 50 N. The artificial crowns were then vertically loaded with a steel sphere until failure occurred. Significant differences in fracture resistance (N) between experimental groups were assessed by nonparametric Mann-Whitney U-test (alpha=.05). Fifty percent of the Sinfony and Sinfony-Vectris crowns cemented with glass ionomer cement loosened after thermal cycling. Thermal cycling resulted in a significant reduction in the mean fracture resistance for Sinfony crowns cemented with GIC, from 2037 N to 1282 N (P=.004). Additional fatigue produced no further effects. Fiber reinforcement significantly increased fracture resistance, from 1555 N to 2326 N (P=.001). The minimal fracture resistance was above 600 N for all combinations of material, cement and loading. Fracture resistance of metal-free Sinfony crowns was significantly increased by

  6. Using thermal analysis techniques for identifying the flash point temperatures of some lubricant and base oils

    Directory of Open Access Journals (Sweden)

    Aksam Abdelkhalik

    2018-03-01

    Full Text Available The flash point (FP temperatures of some lubricant and base oils were measured according to ASTM D92 and ASTM D93. In addition, the thermal stability of the oils was studied using differential scanning calorimeter (DSC and thermogravimetric analysis (TGA under nitrogen atmosphere. The DSC results showed that the FP temperatures, for each oil, were found during the first decomposition step and the temperature at the peak of the first decomposition step was usually higher than FP temperatures. The TGA results indicated that the temperature at which 17.5% weigh loss take placed (T17.5% was nearly identical with the FP temperature (±10 °C that was measured according to ASTM D92. The deviation percentage between FP and T17.5% was in the range from −0.8% to 3.6%. Keywords: Flash point, TGA, DSC

  7. Techniques for determining thermal conductivity and heat capacity under hydrostatic pressure

    Science.gov (United States)

    Andersson, S.; Bäckström, G.

    1986-08-01

    The paper describes a method for measuring the pressure dependence of the thermal conductivity and the heat capacity of hard materials and single crystals. Two parallel metal strips are evaporated onto a flat surface of the specimen, one being used as a heater, the other as a resistance thermometer. The appropriate theoretical expression for a specimen in a liquid medium is fitted to the temperature, sampled at constant time intervals. The thermophysical properties of the liquid high-pressure medium are taken from hot-wire experiments. The procedure has been thoroughly tested at atmospheric pressure using an MgO crystal and glass as specimens and liquids of different characteristics in lieu of high-pressure medium. The accuracy attainable was found to be 3% or better, the standard deviation of the measurements being about 0.3%. The potential of the system was demonstrated by measurements on single-crystal MgO under pressures up to 1 GPa.

  8. Assessment of the ''thermal normalization technique'' for measurement of neutron cross sections vs energy

    International Nuclear Information System (INIS)

    Peelle, R.W.; de Sassure, G.

    1977-01-01

    Refined knowledge of the thermal neutron cross sections of the fissile nuclides and of the (n,α) reaction standards, together with the reasonably well known energy dependence of the latter, have permitted resonance-region and low-keV fissile nuclide cross sections to be based on these standards together with count-rate ratios observed as a function of energy using a pulsed ''white'' source. As one evaluates cross sections for energies above 20 keV, optimum results require combination of cross section shape measurements with all available absolute measurements. The assumptions of the ''thermal normalization method'' are reviewed, and an opinion is given of the status of some of the standards required for its use. The complications which may limit the accuracy of results using the method are listed and examples are given. For the 235 U(n,f) cross section, the option is discussed of defining resonance-region fission integrals as standards. The area of the approximately 9 eV resonances in this nuclide may be known to one percent accuracy, but at present the fission integral from 0.1 to 1.0 keV is known to no better than about two percent. This uncertainty is based on the scatter among independent results, and has not been reduced by the most recent measurements. This uncertainty now limits the accuracy attainable for the 235 U(n,f) cross section below about 50 keV. Suggestions are given to indicate how future detailed work might overcome past sources of error

  9. Neuro-Fuzzy Computational Technique to Control Load Frequency in Hydro-Thermal Interconnected Power System

    Science.gov (United States)

    Prakash, S.; Sinha, S. K.

    2015-09-01

    In this research work, two areas hydro-thermal power system connected through tie-lines is considered. The perturbation of frequencies at the areas and resulting tie line power flows arise due to unpredictable load variations that cause mismatch between the generated and demanded powers. Due to rising and falling power demand, the real and reactive power balance is harmed; hence frequency and voltage get deviated from nominal value. This necessitates designing of an accurate and fast controller to maintain the system parameters at nominal value. The main purpose of system generation control is to balance the system generation against the load and losses so that the desired frequency and power interchange between neighboring systems are maintained. The intelligent controllers like fuzzy logic, artificial neural network (ANN) and hybrid fuzzy neural network approaches are used for automatic generation control for the two area interconnected power systems. Area 1 consists of thermal reheat power plant whereas area 2 consists of hydro power plant with electric governor. Performance evaluation is carried out by using intelligent (ANFIS, ANN and fuzzy) control and conventional PI and PID control approaches. To enhance the performance of controller sliding surface i.e. variable structure control is included. The model of interconnected power system has been developed with all five types of said controllers and simulated using MATLAB/SIMULINK package. The performance of the intelligent controllers has been compared with the conventional PI and PID controllers for the interconnected power system. A comparison of ANFIS, ANN, Fuzzy and PI, PID based approaches shows the superiority of proposed ANFIS over ANN, fuzzy and PI, PID. Thus the hybrid fuzzy neural network controller has better dynamic response i.e., quick in operation, reduced error magnitude and minimized frequency transients.

  10. Yb2Si2O7 Environmental Barrier Coatings Deposited by Various Thermal Spray Techniques: A Preliminary Comparative Study

    Science.gov (United States)

    Bakan, Emine; Marcano, Diana; Zhou, Dapeng; Sohn, Yoo Jung; Mauer, Georg; Vaßen, Robert

    2017-08-01

    Dense, crack-free, uniform, and well-adhered environmental barrier coatings (EBCs) are required to enhance the environmental durability of silicon (Si)-based ceramic matrix composites in high pressure, high gas velocity combustion atmospheres. This paper represents an assessment of different thermal spray techniques for the deposition of Yb2Si2O7 EBCs. The Yb2Si2O7 coatings were deposited by means of atmospheric plasma spraying (APS), high-velocity oxygen fuel spraying (HVOF), suspension plasma spraying (SPS), and very low-pressure plasma spraying (VLPPS) techniques. The initial feedstock, as well as the deposited coatings, were characterized and compared in terms of their phase composition. The as-sprayed amorphous content, microstructure, and porosity of the coatings were further analyzed. Based on this preliminary investigation, the HVOF process stood out from the other techniques as it enabled the production of vertical crack-free coatings with higher crystallinity in comparison with the APS and SPS techniques in atmospheric conditions. Nevertheless, VLPPS was found to be the preferred process for the deposition of Yb2Si2O7 coatings with desired characteristics in a controlled-atmosphere chamber.

  11. Design and fabrication of PMMA-micromachined fluid lens based on electromagnetic actuation on PMMA–PDMS bonded membrane

    International Nuclear Information System (INIS)

    Lee, June Kyoo; Park, Kyung-Woo; Choi, Ju Chan; Kim, Hak-Rin; Kong, Seong Ho

    2012-01-01

    The fabrication of a poly(methyl methacrylate) (PMMA)-micromachined fluid lens with an optimally designed built-in electromagnetic actuator was demonstrated in this study. Through a finite element method, the number of winding turns and the distance between magnetic moments were estimated to design an effective and miniaturized electromagnetic actuator. The lens body composed of PMMA structures was simply and rapidly micromachined using computer numerical control micro-milling. The poly(dimethylsiloxane) (PDMS) membranes for electromagnetic actuation were bonded to the PMMA structures by using the proposed PMMA–PDMS bonding technique, which uses an SiO 2 intermediate layer. A physical repulsive force produced by the electromagnetic actuator applies a controllable fluidic pressure to a fluidic chamber that is sealed with the PDMS membrane, thus allowing dynamic focusing. The focus tunability of the fabricated lens was 67 diopters with a focus hysteresis of less than 1 mm and a response time of 2 ms. The solenoid of the built-in actuator showed negligible thermal crosstalk to the lens. (paper)

  12. Thermal radiation characteristics of nonisothermal cylindrical enclosures using a numerical ray tracing technique

    Science.gov (United States)

    Baumeister, Joseph F.

    1990-01-01

    Analysis of energy emitted from simple or complex cavity designs can lead to intricate solutions due to nonuniform radiosity and irradiation within a cavity. A numerical ray tracing technique was applied to simulate radiation propagating within and from various cavity designs. To obtain the energy balance relationships between isothermal and nonisothermal cavity surfaces and space, the computer code NEVADA was utilized for its statistical technique applied to numerical ray tracing. The analysis method was validated by comparing results with known theoretical and limiting solutions, and the electrical resistance network method. In general, for nonisothermal cavities the performance (apparent emissivity) is a function of cylinder length-to-diameter ratio, surface emissivity, and cylinder surface temperatures. The extent of nonisothermal conditions in a cylindrical cavity significantly affects the overall cavity performance. Results are presented over a wide range of parametric variables for use as a possible design reference.

  13. Intravitreal Phacoemulsification Using Torsional Handpiece for Retained Lens Fragments.

    Science.gov (United States)

    Kumar, Vinod; Takkar, Brijesh

    2016-01-01

    To evaluate the results of intravitreal phacoemulsification with torsional hand piece in eyes with posteriorly dislocated lens fragments. In this prospective, interventional case series, 15 eyes with retained lens fragments following phacoemulsification were included. All patients underwent standard three-port pars plana vitrectomy and intravitreal phacoemulsification using sleeveless, torsional hand piece (OZiL™, Alcon's Infiniti Vision System). Patients were followed up for a minimum of six months to evaluate the visual outcomes and complications. The preoperative best-corrected visual acuity (BCVA) ranged from light perception to 0.3. No complications such as thermal burns of the scleral wound, retinal damage due to flying lens fragments, or difficult lens aspiration occurred during intravitreal phacoemulsification. Mean post-operative BCVA at the final follow-up was 0.5. Two eyes developed cystoid macular edema, which was managed medically. No retinal detachment was noted. Intravitreal phacoemulsification using torsional hand piece is a safe and effective alternative to conventional longitudinal phacofragmentation.

  14. Heating and thermal control of brazing technique to break contamination path for potential Mars sample return

    Science.gov (United States)

    Bao, Xiaoqi; Badescu, Mircea; Sherrit, Stewart; Bar-Cohen, Yoseph; Campos, Sergio

    2017-04-01

    The potential return of Mars sample material is of great interest to the planetary science community, as it would enable extensive analysis of samples with highly sensitive laboratory instruments. It is important to make sure such a mission concept would not bring any living microbes, which may possibly exist on Mars, back to Earth's environment. In order to ensure the isolation of Mars microbes from Earth's Atmosphere, a brazing sealing and sterilizing technique was proposed to break the Mars-to-Earth contamination path. Effectively, heating the brazing zone in high vacuum space and controlling the sample temperature for integrity are key challenges to the implementation of this technique. The break-thechain procedures for container configurations, which are being considered, were simulated by multi-physics finite element models. Different heating methods including induction and resistive/radiation were evaluated. The temperature profiles of Martian samples in a proposed container structure were predicted. The results show that the sealing and sterilizing process can be controlled such that the samples temperature is maintained below the level that may cause damage, and that the brazing technique is a feasible approach to breaking the contamination path.

  15. Oxygen transport through soft contact lens and cornea: Lens characterization and metabolic modeling

    Science.gov (United States)

    Chhabra, Mahendra

    The human cornea requires oxygen to sustain metabolic processes critical for its normal functioning. Any restriction to corneal oxygen supply from the external environment (e.g., by wearing a low oxygen-permeability contact lens) can lead to hypoxia, which may cause corneal edema (swelling), limbal hyperemia, neovascularization, and corneal acidosis. The need for adequate oxygen to the cornea is a major driving force for research and development of hypertransmissible soft contact lenses (SCLs). Currently, there is no standard technique for measuring oxygen permeability (Dk) of hypertransmissible silicone-hydrogel SCLs. In this work, an electrochemistry-based polarographic apparatus was designed, built, and operated to measure oxygen permeability in hypertransmissible SCLs. Unlike conventional methods where a range of lens thickness is needed for determining oxygen permeabilities of SCLs, this apparatus requires only a single lens thickness. The single-lens permeameter provides a reliable, efficient, and economic tool for measuring oxygen permeabilities of commercial hypertransmissible SCLs. The single-lens permeameter measures not only the product Dk, but, following modification, it measures separately diffusivity, D, and solubility, k, of oxygen in hypertransmissible SCLs. These properties are critical for designing better lens materials that ensure sufficient oxygen supply to the cornea. Metabolism of oxygen in the cornea is influenced by contact-lens-induced hypoxia, diseases such as diabetes, surgery, and drug treatment, Thus, estimation of the in-vivo corneal oxygen consumption rate is essential for gauging adequate oxygen supply to the cornea. Therefore, we have developed an unsteady-state reactive-diffusion model for the cornea-contact-lens system to determine in-vivo human corneal oxygen-consumption rate. Finally, a metabolic model was developed to determine the relation between contact-lens oxygen transmissibility (Dk/L) and corneal oxygen deficiency. A

  16. Evolutionary algorithm for optimization of nonimaging Fresnel lens geometry.

    Science.gov (United States)

    Yamada, N; Nishikawa, T

    2010-06-21

    In this study, an evolutionary algorithm (EA), which consists of genetic and immune algorithms, is introduced to design the optical geometry of a nonimaging Fresnel lens; this lens generates the uniform flux concentration required for a photovoltaic cell. Herein, a design procedure that incorporates a ray-tracing technique in the EA is described, and the validity of the design is demonstrated. The results show that the EA automatically generated a unique geometry of the Fresnel lens; the use of this geometry resulted in better uniform flux concentration with high optical efficiency.

  17. Fabrication and characterization of In2S3 thin films deposited by thermal evaporation technique

    International Nuclear Information System (INIS)

    Timoumi, A.; Bouzouita, H.; Kanzari, M.; Rezig, B.

    2005-01-01

    Indium sulphide, In 2 S 3 , thin films present an alternative to conventional CdS films as buffer layer for CIS-based thin film solar cells. The objective is to eliminate toxic cadmium for environmental reasons. Indium sulphide is synthesized and deposited by single source vacuum thermal evaporation method on glass substrates. The films are analyzed by X-ray diffraction (XRD) and spectrophotometric measurements. They have a good crystallinity, homogeneity and adhesion. The X-ray diffraction analysis confirmed the initial amorphous nature of the deposited InS film and phase transition into crystalline In 2 S 3 formed upon annealing at free air for 250 deg. C substrate temperature for 2 h. The optical constants of the deposited films were obtained from the analysis of the experimental recorded transmission and reflectance spectral data over the wavelength range of 300-1800 nm. We note that the films annealed at 250 deg. C for 2 h show a good homogeneity with 80% transmission. An analysis of the optical absorption data of the deposited films revealed an optical direct band gap energy in the range of 2.0-2.2 eV

  18. Infiltration route analysis using thermal observation devices (TOD) and optimization techniques in a GIS environment.

    Science.gov (United States)

    Bang, Soonam; Heo, Joon; Han, Soohee; Sohn, Hong-Gyoo

    2010-01-01

    Infiltration-route analysis is a military application of geospatial information system (GIS) technology. In order to find susceptible routes, optimal-path-searching algorithms are applied to minimize the cost function, which is the summed result of detection probability. The cost function was determined according to the thermal observation device (TOD) detection probability, the viewshed analysis results, and two feature layers extracted from the vector product interim terrain data. The detection probability is computed and recorded for an individual cell (50 m × 50 m), and the optimal infiltration routes are determined with A* algorithm by minimizing the summed costs on the routes from a start point to an end point. In the present study, in order to simulate the dynamic nature of a real-world problem, one thousand cost surfaces in the GIS environment were generated with randomly located TODs and randomly selected infiltration start points. Accordingly, one thousand sets of vulnerable routes for infiltration purposes could be found, which could be accumulated and presented as an infiltration vulnerability map. This application can be further utilized for both optimal infiltration routing and surveillance network design. Indeed, dynamic simulation in the GIS environment is considered to be a powerful and practical solution for optimization problems. A similar approach can be applied to the dynamic optimal routing for civil infrastructure, which requires consideration of terrain-related constraints and cost functions.

  19. Neutron spin echo: A new concept in polarized thermal neutron techniques

    International Nuclear Information System (INIS)

    Mezei, F.

    1980-01-01

    A simple method to change and keep track of neutron beam polarization non-parallel to the magnetic field is described. It makes possible the establishment of a new focusing effect we call neutron spin echo. The technique developed and tested experimentally can be applied in several novel ways, e.g. for neutron spin flipper of superior characteristics, for a very high resolution spectrometer for direct determination of the Fourier transform of the scattering function, for generalised polarization analysis and for the measurement of neutron particle properties with significantly improved precision. (orig.)

  20. Harmonic motion imaging for focused ultrasound (HMIFU): a fully integrated technique for sonication and monitoring of thermal ablation in tissues

    International Nuclear Information System (INIS)

    Maleke, C; Konofagou, E E

    2008-01-01

    FUS (focused ultrasound), or HIFU (high-intensity-focused ultrasound) therapy, a minimally or non-invasive procedure that uses ultrasound to generate thermal necrosis, has been proven successful in several clinical applications. This paper discusses a method for monitoring thermal treatment at different sonication durations (10 s, 20 s and 30 s) using the amplitude-modulated (AM) harmonic motion imaging for focused ultrasound (HMIFU) technique in bovine liver samples in vitro. The feasibility of HMI for characterizing mechanical tissue properties has previously been demonstrated. Here, a confocal transducer, combining a 4.68 MHz therapy (FUS) and a 7.5 MHz diagnostic (pulse-echo) transducer, was used. The therapy transducer was driven by a low-frequency AM continuous signal at 25 Hz, producing a stable harmonic radiation force oscillating at the modulation frequency. A pulser/receiver was used to drive the pulse-echo transducer at a pulse repetition frequency (PRF) of 5.4 kHz. Radio-frequency (RF) signals were acquired using a standard pulse-echo technique. The temperature near the ablation region was simultaneously monitored. Both RF signals and temperature measurements were obtained before, during and after sonication. The resulting axial tissue displacement was estimated using one-dimensional cross correlation. When temperature at the focal zone was above 48 deg. C during heating, the coagulation necrosis occurred and tissue damage was irreversible. The HMI displacement profiles in relation to the temperature and sonication durations were analyzed. At the beginning of heating, the temperature at the focus increased sharply, while the tissue stiffness decreased resulting in higher HMI displacements. This was confirmed by an increase of 0.8 μm deg. C -1 (r = 0.93, p -1 , r = -0.92, p -1 , prior to and after lesion formation in seven bovine liver samples, respectively. This technique was thus capable of following the protein-denatured lesion formation based on the

  1. Surgical treatment of hereditary lens subluxations.

    Science.gov (United States)

    Ozdek, Sengul; Sari, Ayca; Bilgihan, Kamil; Akata, Fikret; Hasanreisoglu, Berati

    2002-01-01

    To evaluate the effectiveness and results of pars plana vitreolensectomy approach with transscleral fixation of intraocular lens in hereditary lens subluxations. Fifteen eyes of 9 consecutive patients with a mean age of 12.8+/-6.2 years (6-26 years) with hereditary lens subluxation were operated on and the results were evaluated in a prospective study. Surgery was considered if best spectacle corrected visual acuity (BSCVA) was less than 20/70. All eyes underwent a 2-port pars plana vitreolensectomy and transscleral fixation of an intraocular lens (IOL). The mean follow-up period was 12.6+/-7.5 months (6-22 months). There was no major intraoperative complication. Preoperatively, 8 eyes (53.3%) had a BSCVA of counting fingers (CF) and 7 eyes (46.6%) had a BSCVA of 20/200 to 20/70. Postoperatively, 14 eyes (93.3%) had a BSCVA of 20/50 or better. None of the patients had IOL decentration or intraocular pressure (IOP) increase during the follow-up period. There was a macular hole formation in 1 eye postoperatively. The early results of pars plana vitreolensectomy with IOL implantation using scleral fixation technique had shown that it not only promises a rapid visual rehabilitation but it is also a relatively safe method. More serious complications, however, may occur in the long term.

  2. Detector LENS as a new tool for solar neutrino spectroscopy

    International Nuclear Information System (INIS)

    Kornoukhov, V.N.

    2001-01-01

    LENS detector is a low-threshold, electron-flavor specific detector for real time measurement of the solar neutrino spectrum at low energies. It is expected that 20 tons of Yb used as a neutrino target should give several hundred events per year. The basic method for implementation of the LENS detector is scintillator technique, namely a liquid scintillator doped (up to 10% in mass) with natural Yb

  3. VENUS-III two-dimensional multi-component thermal hydraulic techniques

    International Nuclear Information System (INIS)

    Weber, D.P.

    1979-01-01

    In recent analyses of the initiating phase in LMFBR core disruptive accidents the energy deposition rate may not be nearly so high as originally thought and the development of material motion and interaction may take place on a time scale considerably larger than the classic disassembly time scale of milliseconds. This introduces a considerably different twist to the problem and it becomes apparent that processes heretofore ignored, such as differential motion and heat exchange, may become important. In addition, time scales may become long enough that substantial core material motion may take place and since rearrangement in more critical configurations cannot be absolutely precluded, capability for extended motion analysis, not easily performed with Lagrangian techniques in multi-dimensions, become desirable. Such considerations provided the motivation for developing a hydrodynamic algorithm to resolve these questions, and an Eulerian rather than Lagrangian frame of reference was chosen, primarily to handle extended motion and interpenetration. The results of the study are described

  4. Assess and Predict Automatic Generation Control Performances for Thermal Power Generation Units Based on Modeling Techniques

    Science.gov (United States)

    Zhao, Yan; Yang, Zijiang; Gao, Song; Liu, Jinbiao

    2018-02-01

    Automatic generation control(AGC) is a key technology to maintain real time power generation and load balance, and to ensure the quality of power supply. Power grids require each power generation unit to have a satisfactory AGC performance, being specified in two detailed rules. The two rules provide a set of indices to measure the AGC performance of power generation unit. However, the commonly-used method to calculate these indices is based on particular data samples from AGC responses and will lead to incorrect results in practice. This paper proposes a new method to estimate the AGC performance indices via system identification techniques. In addition, a nonlinear regression model between performance indices and load command is built in order to predict the AGC performance indices. The effectiveness of the proposed method is validated through industrial case studies.

  5. Phacoemulsification using iris hooks and scleral fixation of the intraocular lens in patients with secondary glaucoma associated with lens subluxation.

    Science.gov (United States)

    Ma, K T; Lee, H K; Seong, G J; Kim, C Y

    2008-09-01

    We described the techniques and results of phacoemulsification using iris hook and scleral fixation of intraocular lens (IOL) in patients with secondary glaucoma associated with lens subluxation. Eight eyes of seven patients with secondary glaucoma associated with lens dislocation, who had undergone the surgery, were retrospectively reviewed. At a mean of 23.5 months+/-13.6 (SD) after the surgery, the mean best-corrected visual acuity improved from 0.24+/-0.21 to 0.83+/-0.3, and mean intraocular pressure (IOP) was changed from 38.4+/-11.4 to 15.5+/-1.8 mmHg at the final examination. There were no vitreoretinal complications except cystoid macular oedema in one eye. The technique appears to be safe and effective in terms of visual rehabilitation and controlling IOP in patients with secondary glaucoma associated with lens subluxation.

  6. In-depth investigation on physicochemical and thermal properties of magnesium (II gluconate using spectroscopic and thermoanalytical techniques

    Directory of Open Access Journals (Sweden)

    Mahendra Kumar Trivedi

    2017-10-01

    Full Text Available Magnesium gluconate is a classical organometallic pharmaceutical compound used for the prevention and treatment of hypomagnesemia as a source of magnesium ion. The present research described the in-depth study on solid state properties viz. physicochemical and thermal properties of magnesium gluconate using sophisticated analytical techniques like PXRD, PSA, FT-IR, UV–Vis spectroscopy, TGA/DTG, and DSC. Magnesium gluconate was found to be crystalline in nature along with the crystallite size ranging from 14.10 to 47.35 nm. The particle size distribution was at d(0.1=6.552 µm, d(0.5=38.299 µm, d(0.9=173.712 µm and D(4,3=67.122 µm along with the specific surface area of 0.372 m2/g. The wavelength for the maximum absorbance was at 198.0 nm. Magnesium gluconate exhibited 88.51% weight loss with three stages of thermal degradation process up to 895.18 °C from room temperature. The TGA/DTG thermograms of the analyte indicated that magnesium gluconate was thermally stable up to around 165 °C. Consequently, the melting temperature of magnesium gluconate was found to be 169.90 °C along with the enthalpy of fusion of 308.7 J/g. Thus, the authors conclude that the achieved results from this study are very useful in pharmaceutical and nutraceutical industries for the identification, characterization and qualitative analysis of magnesium gluconate for preformulation studies and also for developing magnesium gluconate based novel formulation.

  7. #%In-depth investigation on physicochemical and thermal properties of magnesium (II) gluconate using spectroscopic and thermoanalytical techniques

    Institute of Scientific and Technical Information of China (English)

    #

    2017-01-01

    Magnesium gluconate is a classical organometallic pharmaceutical compound used for the prevention and treatment of hypomagnesemia as a source of magnesium ion. The present research described the in-depth study on solid state properties viz. physicochemical and thermal properties of magnesium gluconate using sophisticated analytical techniques like Powder X-ray diffraction (PXRD), particle size analysis ( PSA), Fourier transform infrared (FT-IR) spectrometry, ultraviolet–visible (UV–Vis) spectroscopy, thermogravimetric analysis (TGA)/differential thermogravimetric analysis (DTG), and differential scanning calorimetry (DSC). Magnesium gluconate was found to be crystalline in nature along with the crystallite size ranging from 14.10 to 47.35 nm. The particle size distribution was at d(0.1)=6.552 μm, d(0.5)=38.299 μm, d(0.9)=173.712 μm and D(4,3)=67.122 μm along with the specific surface area of 0.372 m2/g. The wavelength for the maximum absorbance was at 198.0 nm. Magnesium gluconate exhibited 88.51% weight loss with three stages of thermal degradation process up to 895.18 ℃ from room temperature. The TGA/DTG thermograms of the analyte indicated that magnesium gluconate was thermally stable up to around 165 ℃. Consequently, the melting temperature of magnesium gluconate was found to be 169.90 ℃ along with the enthalpy of fusion of 308.7 J/g. Thus, the authors conclude that the achieved results from this study are very useful in pharmaceutical and nutraceutical industries for the identification, characterization and qualitative analysis of magnesium gluconate for preformulation studies and also for developing magnesium gluconate based novel formulation.

  8. Effect of thermal spray processing techniques on the microstructure and properties of Ni-based amorphous coatings

    International Nuclear Information System (INIS)

    Lee, S.M.; Moon, B.M.; Fleury, E.; Ahn, H.S.; Kim, D.H.; Kim, W.T.; Sordelet, D.J.

    2005-01-01

    Metallic amorphous materials have been widely developed thanks to the outstanding properties including high chemical stability, mechanical strength, and magnetic properties. However, with the exception of a few compositions, the limiting factor is the critical cooling rate for the formation of the amorphous phase. For many applications, it is only the contact surface properties that are important, thus the use, of coating techniques such as thermal sprayings has several attractive features. In this paper, we present the microstructure of Ni-based amorphous coatings prepared by laser cladding and vacuum plasma spraying. The utilization of plasma spraying to deposit atomized powder enabled the formation of fully amorphous coating, laser cladding resulted in mostly crystallized structures. Glass forming ability and wear properties of the coatings were discussed as a function of the coating microstructure. (orig.)

  9. Study of the gamma radiation effect on lincomycin by two techniques thermal analysis and fourier transform infrared (FTIR)

    International Nuclear Information System (INIS)

    Al-Zier, A.; Al-Kassiri, H.; Al Aji, Z.

    1999-02-01

    Sample of Lincomycin were irradiated by means of gamma radiation ( 60 Co) at dose rate ca. (408 kGy/h) in the range (3, 5, 15, 20)kGy in presence of air. Samples were investigated using two techniques: Thermal analysis (Differential Scanning Calorimetry (DSC) and Thermogravimetry (TG)) and Fourier Transform Infrared (FTIR). DSC purity study, which depends on Vant Hof equation, showed that the purity of Lincomycin reduced by means of gamma radiation. The purity of theses samples decreased by increasing the dose, and the purity of lincomycin was still above (99%) at dose (10 kGy). To follow up this effects, (FTIR) spectrums of these sample were recorded before and after irradiation. The two peaks at (1500 - 1750 Cm -1 ) which belong to amide group, and the peak at (1050 - 1100 Cm -1 ) which belongs to the S-C groups have reduced. (author)

  10. Study of the gamma radiation effect on the lincomycin by two techniques thermal analysis and fourier transform infrared (FTIR)

    International Nuclear Information System (INIS)

    Al-Zier, A.; Al-Kassiri, H.

    1999-01-01

    Sample of Lincomycin were irradiated by means of gamma radiation ( 60 Co) at dose rate ca. (408 kGy/h) in the range (3, 5, 15, 20)kGy in presence of air. Samples were investigated using two techniques: Thermal analysis (Differential Scanning Calorimetry (DSC) and Thermogravimetry (TG)) and Fourier Transform Infrared (FTIR). DSC purity study, which depends on Vant Hof equation, showed that the purity of Lincomycin reduced by means of gamma radiation. The purity of theses samples decreased by increasing the dose, and the purity of lincomycin was still above (99%) at dose (10 kGy). To follow up this effects, (FTIR) spectrums of these sample were recorded before and after irradiation. The two peaks at (1500 - 1750 Cm -1 ) which belong to amide group, and the peak at (1050 - 1100 Cm -1 ) which belongs to the S-C groups have reduced. (author)

  11. Surface plasmon resonances, optical properties, and electrical conductivity thermal hystersis of silver nanofibers produced by the electrospinning technique.

    Science.gov (United States)

    Barakat, Nasser A M; Woo, Kee-Do; Kanjwal, Muzafar A; Choi, Kyung Eun; Khil, Myung Seob; Kim, Hak Yong

    2008-10-21

    In the present study, silver metal nanofibers have been successfully prepared by using the electrospinning technique. Silver nanofibers have been produced by electrospinning a sol-gel consisting of poly(vinyl alcohol) and silver nitrate. The dried nanofiber mats have been calcined at 850 degrees C in an argon atmosphere. The produced nanofibers do have distinct plasmon resonance compared with the reported silver nanoparticles. Contrary to the introduced shapes of silver nanoparticles, the nanofibers have a blue-shifted plasmon resonance at 330 nm. Moreover, the optical properties study indicated that the synthesized nanofibers have two band gap energies of 0.75 and 2.34 eV. An investigation of the electrical conductivity behavior of the obtained nanofibers shows thermal hystersis. These privileged physical features greatly widen the applications of the prepared nanofibers in various fields.

  12. A Correlation of Thin Lens Approximation to Thick Lens Design by Using Coddington Factors in Lens Design and Manufacturing

    OpenAIRE

    FARSAKOĞLU, Ö. Faruk

    2014-01-01

    The effect of Coddington factors on aberration functions has been analysed using thin lens approximation. Minimizing spherical aberrations of singlet lenses using Coddington factors in lens design depending on lens manufacturing is discussed. Notation of lens test plate pairs used in lens manufacturing is also presented in terms of Coddington shape factors.

  13. Development of method to chemical separation of gallium-67 by thermal diffusion technique

    International Nuclear Information System (INIS)

    Martins, Patricia de Andrade

    2012-01-01

    Radioisotopes of gallium have been studied and evaluated for medical applications since 1949. Over the past 50 years 67 Ga has been widely used in the diagnosis of various diseases, including acute and chronic inflammatory lesions, bacterial or sterile and several types of tumors. In Brazil 30% of clinics that provide services for Nuclear Medicine use 67 Ga citrate and the demand for 67 G a at IPEN-CNEN/SP is 37 GBq (1 Ci)/week. The 67 Ga presents physical half-life of 3.26 days (78 hours) and decays 100% by electron capture to stable 67 Zn. Its decay includes the emission of γ rays with energies of 93.3 keV (37%), 184.6 keV (20.4%), 300.2 keV (16.6%) and 888 keV (26%). In the past 67 Ga was produced by the reaction 68 Zn (p, 2n) 67 Ga at IPEN-CNEN/SP. After irradiation, the target was dissolved in concentrated HCl and the solution percolated through a cationic resin DOWEX 50W-X8, 200-400 mesh, conditioned with 10 mol L -1 HCl. Zinc, nickel and copper were eluted in 10 mol L -1 HCl and 67 Ga 3.5 mol L -1 HCl. The final product was obtained as 67 Ga citrate. This work presents a new, fast, direct and efficient method for the chemical separation of 67 G a by thermal diffusion (heating of the target) combined with concentrated acetic acid extraction. Purification was performed by ion exchange chromatography. Natural zinc electrodeposition was performed on nickel/copper plates as substrate and the zinc deposits were adherent to the substrate, slightly shiny and uniform. The targets were irradiated with 26 MeV protons and integrated current of 10 μA.h. After irradiation, the targets were heated at 300 deg C for 2 hours and placed in contact with concentrated acetic acid for 1 hour. The average yield of extraction of 67 Ga was (72 ± 10)%. This solution was evaporated and the residue was taken up in 0.5 mol L -1 NH 4 OH. The 67 G a was purified on cationic resin Dowex 50WX8 in NH 4 OH medium. The 67 Ga recovery was (98 ± 2)%. This solution was evaporated and taken up

  14. Thermodynamic study on six tricyclic nitrogen heterocyclic compounds by thermal analysis and effusion techniques

    Energy Technology Data Exchange (ETDEWEB)

    Brunetti, Bruno [Istituto per lo Studio dei Materiali Nanostrutturati, Consiglio Nazionale delle Ricerche, Dipartimento di Chimica, Sapienza Università di Roma, P .le A. Moro 5, I-00185 Rome (Italy); Lapi, Andrea [Dipartimento di Chimica, Sapienza Università di Roma, and Istituto CNR di Metodologie Chimiche (IMC-CNR), Sezione Meccanismi di Reazione, Dipartimento di Chimica, Sapienza Università di Roma, P. le A. Moro 5, I-00185 Rome (Italy); Vecchio Ciprioti, Stefano, E-mail: stefano.vecchio@uniroma1.it [Dipartimento S.B.A.I., Sapienza Università di Roma, Via del Castro Laurenziano 7, I-00161 Rome (Italy)

    2016-07-20

    Highlights: • Melting characteristics of tricyclic N-hetero tricyclic compounds were measured by DSC. • Vapor pressures of solid and liquid compounds were measured by effusion and iso-TG. • Thermochemical data from solid and liquid phases were compared with literature. • Good agreement between experimental and literature data with only few exceptions. - Abstract: The molar sublimation and vaporization enthalpies of acridine, phenanthridine, 1,7-phenanthroline, 1,10-phenanthroline, 4,7-phenanthroline and phenazine were determined at the averages of their respective experimental temperature ranges (Δ{sub cr}{sup g}H{sup 0}{sub m} () and Δ{sub l}{sup g}H{sup 0}{sub m} (), respectively) from the temperature dependencies of vapor pressure determined using Knudsen Effusion Mass Loss (KEML), Torsion Effusion (TE) and Isothermal Thermogravimetry (ITG) above their solid and liquid phases. The fusion characteristics (melting temperatures and the molar standard enthalpies of fusion at their melting temperatures) measured by Differential Scanning Calorimetry (DSC) were compared with the available literature values. Solid and liquid vapor pressure data determined by KEML, TE and ITG techniques as well as Δ{sub cr}{sup g}H{sup 0}{sub m} () and Δ{sub l}{sup g}H{sup 0}{sub m} () values, adjusted at 298.15 K by using the values of C{sub p}(cr) and C{sub p}(l) calculated by a well-known group additivity method, were found to be fairly correlated and are consistent with the available literature data. Final Δ{sub cr}{sup g}H{sup 0}{sub m}(298.15 K) values were also provided as weighted averages of all the available data.

  15. UNA REVISIÓN DEL SPRAY TÉRMICO COMO TÉCNICA DE DEPOSICIÓN PARA CAPAS DE BARRERAS TÉRMICAS // THE THERMAL SPRAY AS A DEPOSITION TECHNIQUE FOR THERMAL BARRIER COATING: A REVIEW

    Directory of Open Access Journals (Sweden)

    Eduardo Rondón Briceño

    2015-06-01

    Full Text Available It is important to know the thermal barrier deposition techniques since materials with low thermal conductivity in the barrier can be obtained from them. The dependence of the thermal conductivity with the temperature can be divided into four regions. In this work, we were interested in the study of used techniques for the manufacture of materials with a desirable low thermal conductivity that will be exposed to high temperatures that is to say, materials found in the III and IV region. In these regions the thermal conductivity can be reduced increasing the porosity of the material. Through the study of the thermal barrier deposition techniques we found that the thermal spray produces a coat with high porosity, being the low velocity flame spray technique the best to produce coat of La2Zr2O7 with a minimal thermal conductivity. The thermal spray technique is low cost and almost any material can be thermally sprayed, so this can be considered a very attractive technique for industrial applications. // RESUMEN Es importante conocer las técnicas de deposición de barreras térmicas ya que de ellas depende la obtención de materiales con baja conductividad térmica en la barrera. La dependencia de la conductividad térmica con la temperatura puede dividirse en cuatro regiones. En este trabajo estuvimos interesados en el estudio de las técnicas que se utilizan para la fabricación de materiales sometidos a muy altas temperaturas y donde se desea que su conductividad térmica sea baja, es decir, materiales que se encuentran en la región III y IV. En estas regiones se puede disminuir la conductividad térmica aumentando la porosidad del material. A través del estudio de las técnicas de deposición de barreras térmica, hemos encontrado que la técnica del spray térmico produce una alta porosidad en el recubrimiento, siendo el método de rociado con baja velocidad el mejor método para producir capas de La2Zr2O7 con mínima conductividad t

  16. Effect of Different Catalyst Deposition Technique on Aligned Multiwalled Carbon Nanotubes Grown by Thermal Chemical Vapor Deposition

    Directory of Open Access Journals (Sweden)

    Mohamed Shuaib Mohamed Saheed

    2014-01-01

    Full Text Available The paper reported the investigation of the substrate preparation technique involving deposition of iron catalyst by electron beam evaporation and ferrocene vaporization in order to produce vertically aligned multiwalled carbon nanotubes array needed for fabrication of tailored devices. Prior to the growth at 700°C in ethylene, silicon dioxide coated silicon substrate was prepared by depositing alumina followed by iron using two different methods as described earlier. Characterization analysis revealed that aligned multiwalled carbon nanotubes array of 107.9 µm thickness grown by thermal chemical vapor deposition technique can only be achieved for the sample with iron deposited using ferrocene vaporization. The thick layer of partially oxidized iron film can prevent the deactivation of catalyst and thus is able to sustain the growth. It also increases the rate of permeation of the hydrocarbon gas into the catalyst particles and prevents agglomeration at the growth temperature. Combination of alumina-iron layer provides an efficient growth of high density multiwalled carbon nanotubes array with the steady growth rate of 3.6 µm per minute for the first 12 minutes and dropped by half after 40 minutes. Thicker and uniform iron catalyst film obtained from ferrocene vaporization is attributed to the multidirectional deposition of particles in the gaseous form.

  17. Gas-phase thermal dissociation of uranium hexafluoride: Investigation by the technique of laser-powered homogeneous pyrolysis

    International Nuclear Information System (INIS)

    Bostick, W.D.; McCulla, W.H.; Trowbridge, L.D.

    1987-04-01

    In the gas-phase, uranium hexafluoride decomposes thermally in a quasi-unimolecular reaction to yield uranium pentafluoride and atomic fluorine. We have investigated this reaction using the relatively new technique of laser-powered homogeneous pyrolysis, in which a megawatt infrared laser is used to generate short pulses of high gas temperatures under strictly homogeneous conditions. In our investigation, SiF 4 is used as the sensitizer to absorb energy from a pulsed CO 2 laser and to transfer this energy by collisions with the reactant gas. Ethyl chloride is used as an external standard ''thermometer'' gas to permit estimation of the unimolecular reaction rate constants by a relative rate approach. When UF 6 is the reactant, CF 3 Cl is used as reagent to trap atomic fluorine reaction product, forming CF 4 as a stable indicator which is easily detected by infrared spectroscopy. Using these techniques, we estimate the UF 6 unimolecular reaction rate constant near the high-pressure limit. In the Appendix, we describe a computer program, written for the IBM PC, which predicts unimolecular rate constants based on the Rice-Ramsperger-Kassel theory. Parameterization of the theoretical model is discussed, and recommendations are made for ''appropriate'' input parameters for use in predicting the gas-phase unimolecular reaction rate for UF 6 as a function of temperature and gas composition and total pressure. 85 refs., 17 figs., 14 tabs

  18. Intracapsular lens extraction for the treatment of pupillary block glaucoma associated with anterior subluxation of the crystalline lens.

    Science.gov (United States)

    Kim, Yong Joon; Ha, Seung Joo

    2013-01-01

    To report a case of pupillary block glaucoma associated with spontaneous crystalline lens subluxation into the anterior chamber in a 34-year-old man. Dry vitrectomy was performed for securing enough retrolental space, and an intracapsular lens extraction was then performed via a corneolimbal incision. Additional endothelial cell damage was avoided with an injection of viscoelastics and gentle extraction of the crystalline lens. After deepening of the anterior chamber, scleral fixation of the intraocular lens was performed with an ab externo technique. Two months after the operation, a well-fixated intraocular lens was observed and intraocular pressure was stable. The postoperative corneal astigmatism was -3.5 dpt, and the patient had a best-corrected visual acuity of 20/25. Postoperative complications included decreased endothelial cell count and sector iris paralysis near the incision site. An anteriorly subluxated crystalline lens can cause pupillary block glaucoma in healthy young adults. To prevent intraoperative complications, intracapsular lens extraction with dry vitrectomy can be a good surgical option. The endothelial cell density should be closely monitored after surgery.

  19. A system for routine production of 99mTc by thermal separation technique

    International Nuclear Information System (INIS)

    Sahm, U.; Helus, F.; Krauss, O.; Baier-Borst, W.

    1976-01-01

    Technetium-99m is one of the most widely used radionuclides in diagnostic medicine, and it is a general opinion that 99m Tc and the radiopharmaceuticals obtained from it will be used for a long time. 99m Tc has convenient physical and biological parameters for clinical applications. 99m Tc is formed by the beta decay from its 99 Mo parent. 99 Mo is produced by neutron irradiation of natural Mo or enriched 98 Mo, or as a fission product of 235 U. A third approach is cyclotron production of 99 Mo by proton bombardment of enriched 100 Mo over 100 Mo(p,pn) 99 Mo reaction. The most common method of separating 99m Tc from its 99 Mo parent is the elution of 99m Tc with normal saline from an aluminum oxide column containing adsorbed 99 Mo. The second method is solvent extraction using methylethylketon. The sublimation method is based on different volatility of MoO 3 and Tc 2 O 7 . Previously the development of a practical sublimation generator has been studied and some of them have been used routinely. As a reactor and cyclotron owner we have examined the possibility of producing our own 99m Tc with the aim of being independent from supplier and transportation problems. We have studied the separation of 99m Tc with the aim of being independent from supplier and transportation problems. We have studied the separation of 99m Tc from MoO 3 by complete distillation of gram amounts of natural MoO 3 or enriched 98 MoO 3 irradiated in reactor. The principle of the described method is based on the complete evaporation of MoO 3 and Tc 2 O 7 oxides and its following fractionated condensation. To realize this idea, two different generator systems for repeated multiple separation were developed and studied. The first based on using a two-oven technique. A quartz apparatus is placed in two ovens which are situated side by side and heated to different temperatures. Sweeping gas carries irradiated 99 MoO 3 from a middle part of the first oven heated to a higher temperature (1100 deg. C

  20. Influence of different temperatures on the thermal fatigue behavior and thermal stability of hot-work tool steel processed by a biomimetic couple laser technique

    Science.gov (United States)

    Meng, Chao; Zhou, Hong; Zhou, Ying; Gao, Ming; Tong, Xin; Cong, Dalong; Wang, Chuanwei; Chang, Fang; Ren, Luquan

    2014-04-01

    Three kinds of biomimetic non-smooth shapes (spot-shape, striation-shape and reticulation-shape) were fabricated on the surface of H13 hot-work tool steel by laser. We investigated the thermal fatigue behavior of biomimetic non-smooth samples with three kinds of shapes at different thermal cycle temperature. Moreover, the evolution of microstructure, as well as the variations of hardness of laser affected area and matrix were studied and compared. The results showed that biomimetic non-smooth samples had better thermal fatigue behavior compared to the untreated samples at different thermal cycle temperatures. For a given maximal temperature, the biomimetic non-smooth sample with reticulation-shape had the optimum thermal fatigue behavior, than with striation-shape which was better than that with the spot-shape. The microstructure observations indicated that at different thermal cycle temperatures the coarsening degrees of microstructures of laser affected area were different and the microstructures of laser affected area were still finer than that of the untreated samples. Although the resistance to thermal cycling softening of laser affected area was lower than that of the untreated sample, laser affected area had higher microhardness than the untreated sample at different thermal cycle temperature.

  1. TU-E-201-01: Methods for Eye Lens Dosimetry and Studies On Lens Opacities with Interventionists

    Energy Technology Data Exchange (ETDEWEB)

    Rehani, M. [Massachusetts General Hospital (United States)

    2015-06-15

    awareness can lead to avoidance or even prevention. Learning Objectives: To understand recent changes in eye lens dose limits and thresholds for tissue reactions To understand different approaches to dose estimation for eye lens To learn about challenges in eye lens opacities among staff in interventional fluoroscopy Di Zhang, Toshiba America Medical Systems, Tustin, CA, USA Eye lens radiation dose from brain perfusion CT exams CT perfusion imaging requires repeatedly exposing one location of the head to monitor the uptake and washout of iodinated contrast. The accumulated radiation dose to the eye lens can be high, leading to concerns about potential radiation injury from these scans. CTDIvol assumes continuous z coverage and can overestimate eye lens dose in CT perfusion scans where the table do not increment. The radiation dose to the eye lens from clinical CT brain perfusion studies can be estimated using Monte Carlo simulation methods on voxelized patient models. MDCT scanners from four major manufacturers were simulated and the eye lens doses were estimated using the AAPM posted clinical protocols. They were also compared to CTDIvol values to evaluate the overestimation from CTDIvol. The efficacy of eye lens dose reduction techniques such as tilting the gantry and moving the scan location away from the eyelens were also investigated. Eye lens dose ranged from 81 mGy to 279 mGy, depending on the scanner and protocol used. It is between 59% and 63% of the CTDIvol values reported by the scanners. The eye lens dose is significantly reduced when the eye lenses were not directly irradiated. CTDIvol should not be interpreted as patient dose; this study has shown it to overestimate dose to the eye lens. These results may be used to provide more accurate estimates of actual dose to ensure that protocols are operated safely below thresholds. Tilting the gantry or moving the scanning region further away from the eyes are effective for reducing lens dose in clinical practice

  2. TU-E-201-03: Eye Lens Dosimetry in Radiotherapy Using Contact Lens-Shaped Applicator

    Energy Technology Data Exchange (ETDEWEB)

    Park, J. [Seoul National University Hospital (Korea, Republic of)

    2015-06-15

    awareness can lead to avoidance or even prevention. Learning Objectives: To understand recent changes in eye lens dose limits and thresholds for tissue reactions To understand different approaches to dose estimation for eye lens To learn about challenges in eye lens opacities among staff in interventional fluoroscopy Di Zhang, Toshiba America Medical Systems, Tustin, CA, USA Eye lens radiation dose from brain perfusion CT exams CT perfusion imaging requires repeatedly exposing one location of the head to monitor the uptake and washout of iodinated contrast. The accumulated radiation dose to the eye lens can be high, leading to concerns about potential radiation injury from these scans. CTDIvol assumes continuous z coverage and can overestimate eye lens dose in CT perfusion scans where the table do not increment. The radiation dose to the eye lens from clinical CT brain perfusion studies can be estimated using Monte Carlo simulation methods on voxelized patient models. MDCT scanners from four major manufacturers were simulated and the eye lens doses were estimated using the AAPM posted clinical protocols. They were also compared to CTDIvol values to evaluate the overestimation from CTDIvol. The efficacy of eye lens dose reduction techniques such as tilting the gantry and moving the scan location away from the eyelens were also investigated. Eye lens dose ranged from 81 mGy to 279 mGy, depending on the scanner and protocol used. It is between 59% and 63% of the CTDIvol values reported by the scanners. The eye lens dose is significantly reduced when the eye lenses were not directly irradiated. CTDIvol should not be interpreted as patient dose; this study has shown it to overestimate dose to the eye lens. These results may be used to provide more accurate estimates of actual dose to ensure that protocols are operated safely below thresholds. Tilting the gantry or moving the scanning region further away from the eyes are effective for reducing lens dose in clinical practice

  3. TU-E-201-01: Methods for Eye Lens Dosimetry and Studies On Lens Opacities with Interventionists

    International Nuclear Information System (INIS)

    Rehani, M.

    2015-01-01

    awareness can lead to avoidance or even prevention. Learning Objectives: To understand recent changes in eye lens dose limits and thresholds for tissue reactions To understand different approaches to dose estimation for eye lens To learn about challenges in eye lens opacities among staff in interventional fluoroscopy Di Zhang, Toshiba America Medical Systems, Tustin, CA, USA Eye lens radiation dose from brain perfusion CT exams CT perfusion imaging requires repeatedly exposing one location of the head to monitor the uptake and washout of iodinated contrast. The accumulated radiation dose to the eye lens can be high, leading to concerns about potential radiation injury from these scans. CTDIvol assumes continuous z coverage and can overestimate eye lens dose in CT perfusion scans where the table do not increment. The radiation dose to the eye lens from clinical CT brain perfusion studies can be estimated using Monte Carlo simulation methods on voxelized patient models. MDCT scanners from four major manufacturers were simulated and the eye lens doses were estimated using the AAPM posted clinical protocols. They were also compared to CTDIvol values to evaluate the overestimation from CTDIvol. The efficacy of eye lens dose reduction techniques such as tilting the gantry and moving the scan location away from the eyelens were also investigated. Eye lens dose ranged from 81 mGy to 279 mGy, depending on the scanner and protocol used. It is between 59% and 63% of the CTDIvol values reported by the scanners. The eye lens dose is significantly reduced when the eye lenses were not directly irradiated. CTDIvol should not be interpreted as patient dose; this study has shown it to overestimate dose to the eye lens. These results may be used to provide more accurate estimates of actual dose to ensure that protocols are operated safely below thresholds. Tilting the gantry or moving the scanning region further away from the eyes are effective for reducing lens dose in clinical practice

  4. TU-E-201-03: Eye Lens Dosimetry in Radiotherapy Using Contact Lens-Shaped Applicator

    International Nuclear Information System (INIS)

    Park, J.

    2015-01-01

    awareness can lead to avoidance or even prevention. Learning Objectives: To understand recent changes in eye lens dose limits and thresholds for tissue reactions To understand different approaches to dose estimation for eye lens To learn about challenges in eye lens opacities among staff in interventional fluoroscopy Di Zhang, Toshiba America Medical Systems, Tustin, CA, USA Eye lens radiation dose from brain perfusion CT exams CT perfusion imaging requires repeatedly exposing one location of the head to monitor the uptake and washout of iodinated contrast. The accumulated radiation dose to the eye lens can be high, leading to concerns about potential radiation injury from these scans. CTDIvol assumes continuous z coverage and can overestimate eye lens dose in CT perfusion scans where the table do not increment. The radiation dose to the eye lens from clinical CT brain perfusion studies can be estimated using Monte Carlo simulation methods on voxelized patient models. MDCT scanners from four major manufacturers were simulated and the eye lens doses were estimated using the AAPM posted clinical protocols. They were also compared to CTDIvol values to evaluate the overestimation from CTDIvol. The efficacy of eye lens dose reduction techniques such as tilting the gantry and moving the scan location away from the eyelens were also investigated. Eye lens dose ranged from 81 mGy to 279 mGy, depending on the scanner and protocol used. It is between 59% and 63% of the CTDIvol values reported by the scanners. The eye lens dose is significantly reduced when the eye lenses were not directly irradiated. CTDIvol should not be interpreted as patient dose; this study has shown it to overestimate dose to the eye lens. These results may be used to provide more accurate estimates of actual dose to ensure that protocols are operated safely below thresholds. Tilting the gantry or moving the scanning region further away from the eyes are effective for reducing lens dose in clinical practice

  5. Magnifying lens for 800 MeV proton radiography

    International Nuclear Information System (INIS)

    Merrill, F. E.; Campos, E.; Espinoza, C.; Hogan, G.; Hollander, B.; Lopez, J.; Mariam, F. G.; Morley, D.; Morris, C. L.; Murray, M.; Saunders, A.; Schwartz, C.; Thompson, T. N.

    2011-01-01

    This article describes the design and performance of a magnifying magnetic-lens system designed, built, and commissioned at the Los Alamos National Laboratory (LANL) for 800 MeV flash proton radiography. The technique of flash proton radiography has been developed at LANL to study material properties under dynamic loading conditions through the analysis of time sequences of proton radiographs. The requirements of this growing experimental program have resulted in the need for improvements in spatial radiographic resolution. To meet these needs, a new magnetic lens system, consisting of four permanent magnet quadrupoles, has been developed. This new lens system was designed to reduce the second order chromatic aberrations, the dominant source of image blur in 800 MeV proton radiography, as well as magnifying the image to reduce the blur contribution from the detector and camera systems. The recently commissioned lens system performed as designed, providing nearly a factor of three improvement in radiographic resolution.

  6. Pentacam Scheimpflug quantitative imaging of the crystalline lens and intraocular lens.

    Science.gov (United States)

    Rosales, Patricia; Marcos, Susana

    2009-05-01

    To implement geometrical and optical distortion correction methods for anterior segment Scheimpflug images obtained with a commercially available system (Pentacam, Oculus Optikgeräte GmbH). Ray tracing algorithms were implemented to obtain corrected ocular surface geometry from the original images captured by the Pentacam's CCD camera. As details of the optical layout were not fully provided by the manufacturer, an iterative procedure (based on imaging of calibrated spheres) was developed to estimate the camera lens specifications. The correction procedure was tested on Scheimpflug images of a physical water cell model eye (with polymethylmethacrylate cornea and a commercial IOL of known dimensions) and of a normal human eye previously measured with a corrected optical and geometrical distortion Scheimpflug camera (Topcon SL-45 [Topcon Medical Systems Inc] from the Vrije University, Amsterdam, Holland). Uncorrected Scheimpflug images show flatter surfaces and thinner lenses than in reality. The application of geometrical and optical distortion correction algorithms improves the accuracy of the estimated anterior lens radii of curvature by 30% to 40% and of the estimated posterior lens by 50% to 100%. The average error in the retrieved radii was 0.37 and 0.46 mm for the anterior and posterior lens radii of curvature, respectively, and 0.048 mm for lens thickness. The Pentacam Scheimpflug system can be used to obtain quantitative information on the geometry of the crystalline lens, provided that geometrical and optical distortion correction algorithms are applied, within the accuracy of state-of-the art phakometry and biometry. The techniques could improve with exact knowledge of the technical specifications of the instrument, improved edge detection algorithms, consideration of aspheric and non-rotationally symmetrical surfaces, and introduction of a crystalline gradient index.

  7. Characteristics of the thick, compound refractive lens

    International Nuclear Information System (INIS)

    Pantell, Richard H.; Feinstein, Joseph; Beguiristain, H. Raul; Piestrup, Melvin A.; Gary, Charles K.; Cremer, Jay T.

    2003-01-01

    A compound refractive lens (CRL), consisting of a series of N closely spaced lens elements each of which contributes a small fraction of the total focusing, can be used to focus x rays or neutrons. The thickness of a CRL can be comparable to its focal length, whereupon a thick-lens analysis must be performed. In contrast with the conventional optical lens, where the ray inside the lens follows a straight line, the ray inside the CRL is continually changing direction because of the multiple refracting surfaces. Thus the matrix representation for the thick CRL is quite different from that for the thick optical lens. Principal planes can be defined such that the thick-lens matrix can be converted to that of a thin lens. For a thick lens the focal length is greater than for a thin lens with the same lens curvature, but this lengthening effect is less for the CRL than for the conventional optical lens

  8. Microbial structures in an Alpine Thermal Spring - Microscopic techniques for the examination of Biofilms in a Subsurface Environment

    Science.gov (United States)

    Dornmayr-Pfaffenhuemer, Marion; Pierson, Elisabeth; Janssen, Geert-Jan; Stan-Lotter, Helga

    2010-05-01

    The research into extreme environments hast important implications for biology and other sciences. Many of the organisms found there provide insights into the history of Earth. Life exists in all niches where water is present in liquid form. Isolated environments such as caves and other subsurface locations are of interest for geomicrobiological studies. And because of their "extra-terrestrial" conditions such as darkness and mostly extreme physicochemical state they are also of astrobiological interest. The slightly radioactive thermal spring at Bad Gastein (Austria) was therefore examined for the occurrence of subsurface microbial communities. The surfaces of the submerged rocks in this warm spring were overgrown by microbial mats. Scanning electron microscopy (SEM) performed by the late Dr. Wolfgang Heinen revealed an interesting morphological diversity in biofilms found in this environment (1, 2). Molecular analysis of the community structure of the radioactive subsurface thermal spring was performed by Weidler et al. (3). The growth of these mats was simulated using sterile glass slides which were exposed to the water stream of the spring. Those mats were analysed microscopically. Staining, using fluorescent dyes such as 4',6-Diamidino-2-phenylindol (DAPI), gave an overview of the microbial diversity of these biofilms. Additional SEM samples were prepared using different fixation protocols. Scanning confocal laser microscopy (SCLM) allowed a three dimensional view of the analysed biofilms. This work presents some electron micrographs of Dr. Heinen and additionally new microscopic studies of the biofilms formed on the glass slides. The appearances of the new SEM micrographs were compared to those of Dr. Heinen that were done several years ago. The morphology and small-scale distribution in the microbial mat was analyzed by fluorescence microscopy. The examination of natural biomats and biofilms grown on glass slides using several microscopical techniques

  9. Electrically switchable holographic liquid crystal/polymer Fresnel lens using a Michelson interferometer.

    Science.gov (United States)

    Jashnsaz, Hossein; Mohajerani, Ezeddin; Nemati, Hossein; Razavi, Seyed Hossein; Alidokht, Isa Ahmad

    2011-06-10

    A holographic technique for fabricating an electrically switchable liquid crystal/polymer composite Fresnel lens is reported. A Michelson interferometer is used to produce the required Fresnel pattern, by placing a convex lens into one path of the interferometer. Simplicity of the method and the possibility of fabricating different focal length lenses in a single arrangement are advantages of the method. The performance of the fabricated lens was demonstrated and its electro-optical properties were investigated for its primary focal length.

  10. Reassessment of the NH4 NO3 thermal decomposition technique for calibration of the N2 O isotopic composition.

    Science.gov (United States)

    Mohn, Joachim; Gutjahr, Wilhelm; Toyoda, Sakae; Harris, Eliza; Ibraim, Erkan; Geilmann, Heike; Schleppi, Patrick; Kuhn, Thomas; Lehmann, Moritz F; Decock, Charlotte; Werner, Roland A; Yoshida, Naohiro; Brand, Willi A

    2016-09-08

    In the last few years, the study of N 2 O site-specific nitrogen isotope composition has been established as a powerful technique to disentangle N 2 O emission pathways. This trend has been accelerated by significant analytical progress in the field of isotope-ratio mass-spectrometry (IRMS) and more recently quantum cascade laser absorption spectroscopy (QCLAS). Methods The ammonium nitrate (NH 4 NO 3 ) decomposition technique provides a strategy to scale the 15 N site-specific (SP ≡ δ 15 N α - δ 15 N β ) and bulk (δ 15 N bulk  = (δ 15 N α  + δ 15 N β )/2) isotopic composition of N 2 O against the international standard for the 15 N/ 14 N isotope ratio (AIR-N 2 ). Within the current project 15 N fractionation effects during thermal decomposition of NH 4 NO 3 on the N 2 O site preference were studied using static and dynamic decomposition techniques. The validity of the NH 4 NO 3 decomposition technique to link NH 4 + and NO 3 - moiety-specific δ 15 N analysis by IRMS to the site-specific nitrogen isotopic composition of N 2 O was confirmed. However, the accuracy of this approach for the calibration of δ 15 N α and δ 15 N β values was found to be limited by non-quantitative NH 4 NO 3 decomposition in combination with substantially different isotope enrichment factors for the conversion of the NO 3 - or NH 4 + nitrogen atom into the α or β position of the N 2 O molecule. The study reveals that the completeness and reproducibility of the NH 4 NO 3 decomposition reaction currently confine the anchoring of N 2 O site-specific isotopic composition to the international isotope ratio scale AIR-N 2 . The authors suggest establishing a set of N 2 O isotope reference materials with appropriate site-specific isotopic composition, as community standards, to improve inter-laboratory compatibility. This article is protected by copyright. All rights reserved.

  11. Investigate the electrical and thermal properties of the low temperature resistant silver nanowire fabricated by two-beam laser technique

    Science.gov (United States)

    He, Gui-Cang; Dong, Xian-Zi; Liu, Jie; Lu, Heng; Zhao, Zhen-Sheng

    2018-05-01

    A two-beam laser fabrication technique is introduced to fabricate the single silver nanowire (AgNW) on polyethylene terephthalate (PET) substrate. The resistivity of the AgNW is (1.31 ± 0.05) × 10-7 Ω·m, which is about 8 times of the bulk silver resistivity (1.65 × 10-8 Ω·m). The AgNW electrical resistance is measured in temperature range of 10-300 K and fitted with the Bloch-Grüneisen formula. The fitting results show that the residue resistance is 153 Ω, the Debye temperature is 210 K and the electron-phonon coupling constant is (5.72 ± 0.24) × 10-8 Ω·m. Due to the surface scattering, the Debye temperature and the electron-phonon coupling constant are lower than those of bulk silver, and the residue resistance is bigger than that of bulk silver. Thermal conductivity of the single AgNW is calculated in the corresponding temperature range, which is the biggest at the temperature approaching the Debye temperature. The AgNW on PET substrate is the low temperature resistance material and is able to be operated stably at such a low temperature of 10 K.

  12. A Technique for Mitigating Thermal Stress and Extending Life Cycle of Power Electronic Converters Used for Wind Turbines

    Directory of Open Access Journals (Sweden)

    Canras Batunlu

    2015-11-01

    Full Text Available Over the last two decades, various models have been developed to assess and improve the reliability of power electronic conversion systems (PECs with a focus on those used for wind turbines. However, only few studies have dealt with mitigating the PECs thermo-mechanical effects on their reliability taking into account variations in wind characteristics. This work critically investigates this issue and attempts to offer a mitigating technique by, first, developing realistic full scale (FS and partial scale (PS induction generator models combined with two level back-to-back PECs. Subsequently, deriving a driving algorithm, which reduces PEC’s operating temperature by controlling its switching patterns. The developed switching procedure ensures minimum temperature fluctuations by adapting the variable DC link and system’s frequency of operation. It was found for both FS and PS topologies, that the generator side converters have higher mean junction temperatures where the grid side ones have more fluctuations on their thermal profile. The FS and PS cycling temperatures were reduced by 12 °C and 5 °C, respectively. Moreover, this led to a significant improvement in stress; approximately 27 MPa stress reduction for the FS induction generator PEC.

  13. Application of the Modified Source Multiplication (MSM) technique to subcritical reactivity worth measurements in thermal and fast reactor systems

    International Nuclear Information System (INIS)

    Blaise, P.; Fougeras, P.; Mellier, F.

    2009-01-01

    The Amplified Source Multiplication (ASM) method and its improved Modified Source Multiplication (MSM) method have been widely used in the CEA's EOLE and MASURCA critical facilities over the past decades for the determination of reactivity worths by using fission chambers in subcritical configurations. They have been successfully applied to absorber (single or clusters) worth measurement in both thermal and fast spectra, or for (sodium or water) void reactivity worths. The ASM methodology, which is the basic technique to estimate a reactivity worth, uses relatively simple relationships between count rates of efficient miniature fission chambers located in slightly subcritical reference and perturbed configurations. If this method works quite well for small reactivity variation (a few effective delayed neutron fraction), its raw results needs to be corrected to take into account the flux perturbation in the fission chamber. This is performed by applying to the measurement a correction factor called MSM. Its characteristics is to take into account the local space and energy variation of the spectrum in the fission chamber, through standard perturbation theory applied to neutron transport calculation in the perturbed configuration. The proposed paper describes in details both methodologies, with their associated uncertainties. Applications on absorber cluster worth in the MISTRAL-4 full MOX mock-up core and the last core loaded in MASURCA show the importance of the MSM correction on raw data. (authors)

  14. Microstructural, nanomechanical, and microtribological properties of Pb thin films prepared by pulsed laser deposition and thermal evaporation techniques

    Energy Technology Data Exchange (ETDEWEB)

    Broitman, Esteban, E-mail: esbro@ifm.liu.se [Thin Film Physics Division, IFM, Linköping University, SE-581 83 Linköping (Sweden); Flores-Ruiz, Francisco J. [Thin Film Physics Division, IFM, Linköping University, SE-581 83 Linköping, Sweden and Centro de Investigación y de Estudios Avanzados del I.P.N., Unidad Querétaro, Querétaro 76230 (Mexico); Di Giulio, Massimo [Università del Salento, Dipartimento di Matematica e Fisica “E. De Giorgi”, 73100 Lecce (Italy); Gontad, Francisco; Lorusso, Antonella; Perrone, Alessio [Università del Salento, Dipartimento di Matematica e Fisica “E. De Giorgi”, 73100 Lecce, Italy and INFN-Istituto Nazionale di Fisica Nucleare, 73100 Lecce (Italy)

    2016-03-15

    In this work, the authors compare the morphological, structural, nanomechanical, and microtribological properties of Pb films deposited by thermal evaporation (TE) and pulsed laser deposition (PLD) techniques onto Si (111) substrates. Films were investigated by scanning electron microscopy, surface probe microscopy, and x-ray diffraction in θ-2θ geometry to determine their morphology, root-mean-square (RMS) roughness, and microstructure, respectively. TE films showed a percolated morphology with densely packed fibrous grains while PLD films had a granular morphology with a columnar and tightly packed structure in accordance with the zone growth model of Thornton. Moreover, PLD films presented a more polycrystalline structure with respect to TE films, with RMS roughness of 14 and 10 nm, respectively. Hardness and elastic modulus vary from 2.1 to 0.8 GPa and from 14 to 10 GPa for PLD and TE films, respectively. A reciprocal friction test has shown that PLD films have lower friction coefficient and wear rate than TE films. Our study has demonstrated for first time that, at the microscale, Pb films do not show the same simple lubricious properties measured at the macroscale.

  15. Thermal expansion behavior study of Co nanowire array with in situ x-ray diffraction and x-ray absorption fine structure techniques

    Science.gov (United States)

    Mo, Guang; Cai, Quan; Jiang, Longsheng; Wang, Wei; Zhang, Kunhao; Cheng, Weidong; Xing, Xueqing; Chen, Zhongjun; Wu, Zhonghua

    2008-10-01

    In situ x-ray diffraction and x-ray absorption fine structure techniques were used to study the structural change of ordered Co nanowire array with temperature. The results show that the Co nanowires are polycrystalline with hexagonal close packed structure without phase change up until 700 °C. A nonlinear thermal expansion behavior has been found and can be well described by a quadratic equation with the first-order thermal expansion coefficient of 4.3×10-6/°C and the second-order thermal expansion coefficient of 5.9×10-9/°C. The mechanism of this nonlinear thermal expansion behavior is discussed.

  16. Temperature dependant thermal and mechanical properties of a metal-phase change layer interface using the time resolved pump probe technique

    International Nuclear Information System (INIS)

    Schick, V; Battaglia, J-L; Kusiak, A; Rossignol, C; Wiemer, C

    2011-01-01

    Time Resolved Pump Probe (TRPP) technique has been implemented to study the thermal and mechanical properties of Ge 2 Sb 2 Te 5 (GST) film deposited on a silicon substrate. According to the knowledge of the thermal properties of the GST layer, the temperature dependant Thermal Boundary Resistance (TBR) at the metal-GST interface is evaluated. Measuring the acoustic oscillation and more particularly its damping leads to characterize the adhesion at the metal - GST interface. This quantity can be efficiently related to the temperature dependent TBR in the 25 deg. C - 400 deg. C range. The TBR increases with temperature and follows the changes of the crystalline structure of materials. A linear relation between the acoustic reflection coefficient and the logarithm of the thermal boundary resistance is found.

  17. Direct comparison of the thermal lenses of diode-end-pumped Nd:YVO4 and Nd:GdVO4 lasers using a simple evaluation technique

    CSIR Research Space (South Africa)

    Esser, MJD

    2006-01-01

    Full Text Available In this work, the thermal lenses generated in diode-end-pumped Nd:YVO4 and Nd:GdVO4 lasers were evaluated and compared using a simple technique based on the stability criteria of a plane-parallel laser resonator [example 1], as shown in the top...

  18. Development of the fabrication of ultra-low density ploy (4-methyl-1-pentene) (PMP) foams by thermal induced phase-inversion technique

    International Nuclear Information System (INIS)

    Zhang Lin; Wang Chaoyang; Luo Xuan; Du Kai; Tu Haiyan; Fan Hong; Luo Qing; Yuan Guanghui; Huang Lizhen

    2003-01-01

    By thermally induced phase-inversion technique, ploy (4-methyl-1-pentene) (PMP) foams are successfully prepared; the density and pore size are 3-80 mg/cm 3 and 1-20 μm respectively. Durene/naphthalene (60/40) is confirmed as the suitable solvent/nonsolvent binary system. The PMP's thermal properties are characterized by TG-DSC system. It is found that the foams thermal properties depend on the density. The thermal analysis method is utilized to measure the gelation of PMP in the binary solvent/nonsolvent system. The range of gelation temperature is preliminarily determined. The influence of mixture system composition and the cooling rate during the making of foams is discussed. TG-DSC is applied to determine the thermal properties of low-density PMP foams prepared in the laboratory. And the effect of density change on the thermal stability of foams are studied. The thermal analysis data play a great role in improving the foam quality. (authors)

  19. Crystalline lens radioprotectors

    International Nuclear Information System (INIS)

    Belkacemi, Y.; Pasquier, D.; Castelain, B.; Lartigau, E.; Warnet, J.M.

    2003-01-01

    During more than a half of century, numerous compounds have been tested in different models against radiation-induced cataract. In this report, we will review the radioprotectors that have been already tested for non-human crystalline lens protection. We will focus on the most important published studies in this topic and the mechanisms of cyto-protection reported in. vitro and in. vivo from animals. The most frequent mechanisms incriminated in the cyto-protective effect are: free radical scavenging, limitation of lipid peroxidation, modulation of cycle progression increase of intracellular reduced glutathione pool, reduction of DNA strand breaks and limitation of apoptotic cell death. Arnifostine (or Ethyol) and anethole dithiolethione (or Sulfarlem), already used clinically as chemo- and radio-protectants, could be further test?r for ocular radioprotection particularly for radiation-induced cataract. (author)

  20. Wedged multilayer Laue lens

    International Nuclear Information System (INIS)

    Conley, Ray; Liu Chian; Qian Jun; Kewish, Cameron M.; Macrander, Albert T.; Yan Hanfei; Maser, Joerg; Kang, Hyon Chol; Stephenson, G. Brian

    2008-01-01

    A multilayer Laue lens (MLL) is an x-ray focusing optic fabricated from a multilayer structure consisting of thousands of layers of two different materials produced by thin-film deposition. The sequence of layer thicknesses is controlled to satisfy the Fresnel zone plate law and the multilayer is sectioned to form the optic. An improved MLL geometry can be created by growing each layer with an in-plane thickness gradient to form a wedge, so that every interface makes the correct angle with the incident beam for symmetric Bragg diffraction. The ultimate hard x-ray focusing performance of a wedged MLL has been predicted to be significantly better than that of a nonwedged MLL, giving subnanometer resolution with high efficiency. Here, we describe a method to deposit the multilayer structure needed for an ideal wedged MLL and report our initial deposition results to produce these structures

  1. Improved illumination system of laparoscopes using an aspherical lens array.

    Science.gov (United States)

    Wu, Rengmao; Qin, Yi; Hua, Hong

    2016-06-01

    The current fiber-based illumination systems of laparoscopes are unable to uniformly illuminate a large enough area in abdomen due to the limited numerical aperture (NA) of the fiber bundle. Most energy is concentrated in a small region at the center of the illumination area. This limitation becomes problematic in laparoscopes which require capturing a wide field of view. In this paper, we propose an aspherical lens array which is used to direct the outgoing rays from the fiber bundle of laparoscope to produce a more uniformly illuminated, substantially larger field coverage than standalone fiber source. An intensity feedback method is developed to design the aspherical lens unit for extended non-Lambertian sources, which is the key to the design of this lens array. By this method, the lens unit is obtained after only one iteration, and the lens array is constructed by Boolean operation. Then, the ray-tracing technique is used to verify the design. Further, the lens array is fabricated and experimental tests are performed. The results clearly show that the well-illuminated area is increased to about 0.107m(2) from 0.02m(2) (about 5x larger than a standard fiber illumination source). More details of the internal organs can be clearly observed under this improved illumination condition, which also reflects the significant improvement in the optical performance of the laparoscope.

  2. Intraocular lens calculations in atypical eyes

    Directory of Open Access Journals (Sweden)

    Aazim A Siddiqui

    2017-01-01

    Full Text Available Cataract surgery is the most performed surgical procedure in the field of ophthalmology. The process of intraocular lens (IOL calculations is a critical step to achieving successful outcomes. Many IOL formulae exist to guide surgeons through the difficult process of picking the most appropriate lens to achieve a certain target refraction. However, these formulae reach within 0.50 diopters of the target refraction only 75% of the time, leaving 25% of the eyes with a significant refractive surprise. A literature review was performed to investigate all the relevant published material on the history, progress, and recent advancements of IOL calculations. Based on this review, the appropriate history, evolution, progress, limitations, and recent advancements are analyzed and explained. Although the modern IOL formulae and biometric devices perform well for average eyes, they are suboptimal for eyes with atypical biometric parameters and also those that are postrefractive and keratoconic. There has not been a single, perfect formula that can resolve the complexities of this process. Various methods of formula optimization and newer generation of IOL formulae and devices may hold the key to improving outcomes in both typical and atypical eyes. These solutions minimize refractive error by introducing new input parameters and complex mathematical techniques to better estimate postoperative lens position.

  3. Scleral suspension pars-plana lensectomy for ectopia lentis followed by suture fixation of intraocular lens

    Directory of Open Access Journals (Sweden)

    Mitra Sandip

    2001-01-01

    Full Text Available Purpose: To describe a simple technique of scleral suspension-pars plana lensectomy (SS-PPL in acquired and congenital ectopia lentis and scleral fixation of intraocular lens (IOL. Materials and Methods: Twenty eyes of 16 patients (12 unilateral and 4 bilateral cases of "essential familial lens subluxation" aged 10-40 years (mean 25 years underwent SS-PPL with implantation of scleral fixated IOL. Indications for surgery were best-corrected visual acuity <6/18, bisection of pupil by the lens, and lens-induced glaucoma. Prerequisites for SS-PPL were, visibility of part of the lens in the pupillary area and soft lens. Results: Postoperative visual acuity ranged from 6/6 - 6/36. Lens tilt in 3 cases(15% and small decentration in 2 cases(10% were seen; however these did not seriously compromise the visual result. Scant vitreous bleeding on the first postoperative day was seen in 3 cases (15%. Conclusion: The advantages of the scleral suspension of subluxated lens prior to lensectomy include stabilization; it allows proper viewing of the lens, avoids injury to the iris and cliary body during lensectomy and reduces the possibility of dislocation of the lens.

  4. Evaluation of the accuracy of thermal dissociation CRDS and LIF techniques for atmospheric measurement of reactive nitrogen species

    Science.gov (United States)

    Womack, Caroline C.; Neuman, J. Andrew; Veres, Patrick R.; Eilerman, Scott J.; Brock, Charles A.; Decker, Zachary C. J.; Zarzana, Kyle J.; Dube, William P.; Wild, Robert J.; Wooldridge, Paul J.; Cohen, Ronald C.; Brown, Steven S.

    2017-05-01

    The sum of all reactive nitrogen species (NOy) includes NOx (NO2 + NO) and all of its oxidized forms, and the accurate detection of NOy is critical to understanding atmospheric nitrogen chemistry. Thermal dissociation (TD) inlets, which convert NOy to NO2 followed by NO2 detection, are frequently used in conjunction with techniques such as laser-induced fluorescence (LIF) and cavity ring-down spectroscopy (CRDS) to measure total NOy when set at > 600 °C or speciated NOy when set at intermediate temperatures. We report the conversion efficiency of known amounts of several representative NOy species to NO2 in our TD-CRDS instrument, under a variety of experimental conditions. We find that the conversion efficiency of HNO3 is highly sensitive to the flow rate and the residence time through the TD inlet as well as the presence of other species that may be present during ambient sampling, such as ozone (O3). Conversion of HNO3 at 400 °C, nominally the set point used to selectively convert organic nitrates, can range from 2 to 6 % and may represent an interference in measurement of organic nitrates under some conditions. The conversion efficiency is strongly dependent on the operating characteristics of individual quartz ovens and should be well calibrated prior to use in field sampling. We demonstrate quantitative conversion of both gas-phase N2O5 and particulate ammonium nitrate in the TD inlet at 650 °C, which is the temperature normally used for conversion of HNO3. N2O5 has two thermal dissociation steps, one at low temperature representing dissociation to NO2 and NO3 and one at high temperature representing dissociation of NO3, which produces exclusively NO2 and not NO. We also find a significant interference from partial conversion (5-10 %) of NH3 to NO at 650 °C in the presence of representative (50 ppbv) levels of O3 in dry zero air. Although this interference appears to be suppressed when sampling ambient air, we nevertheless recommend regular

  5. Assessment of wave propagation on surfaces of crystalline lens with phase sensitive optical coherence tomography

    International Nuclear Information System (INIS)

    Manapuram, R K; Larin, K V; Baranov, S A; Manne, V G R; Mashiatulla, M; Sudheendran, N; Aglyamov, S; Emelianov, S

    2011-01-01

    We propose a real-time technique based on phase-sensitive swept source optical coherence tomography (PhS-SSOCT) modality for noninvasive quantification of very small optical path length changes produced on the surface of a mouse crystalline lens. Propagation of submicron mechanical waves on the surface of the lens was induced by periodic mechanical stimulation. Obtained results demonstrate that the described method is capable of detecting minute damped vibrations with amplitudes as small as 30 nanometers on the lens surface and hence, PhS-SSOCT could be potentially used to assess biomechanical properties of a crystalline lens with high accuracy and sensitivity

  6. Thermal and non-thermal preservation techniques of tiger nuts' beverage "horchata de chufa". Implications for food safety, nutritional and quality properties.

    Science.gov (United States)

    Roselló-Soto, Elena; Poojary, Mahesha M; Barba, Francisco J; Koubaa, Mohamed; Lorenzo, Jose M; Mañes, Jordi; Moltó, Juan Carlos

    2018-03-01

    "Horchata de chufa" is a traditional Spanish beverage produced from tiger nuts (Cyperus esculentus L.). Due to its richness in nutritional compounds, it is highly perishable and its conservation by pasteurization and/or adding preservatives is required. Although efficient, conventional thermal treatment for pasteurization induces changes in the nutritional and sensory properties. Replacing conventional pasteurization by non-thermal technologies such as pulsed electric fields, ultraviolet, and high pressure, combined with moderate temperatures (preservation of the most thermo-sensitive molecules. Accordingly, this review deals with the description of the most relevant non-thermal technologies applied to preserve "horchata" beverage in order to extend the shelf life and inactivate pathogenic microorganisms as well as to preserve the nutritional and quality properties of this food beverage. Copyright © 2017 Elsevier Ltd. All rights reserved.

  7. Manufacturing PDMS micro lens array using spin coating under a multiphase system

    International Nuclear Information System (INIS)

    Sun, Rongrong; Yang, Hanry; Rock, D Mitchell; Danaei, Roozbeh; Panat, Rahul; Kessler, Michael R; Li, Lei

    2017-01-01

    The development of micro lens arrays has garnered much interest due to increased demand of miniaturized systems. Traditional methods for manufacturing micro lens arrays have several shortcomings. For example, they require expensive facilities and long lead time, and traditional lens materials (i.e. glass) are typically heavy, costly and difficult to manufacture. In this paper, we explore a method for manufacturing a polydimethylsiloxane (PDMS) micro lens array using a simple spin coating technique. The micro lens array, formed under an interfacial tension dominated system, and the influence of material properties and process parameters on the fabricated lens shape are examined. The lenses fabricated using this method show comparable optical properties—including surface finish and image quality—with a reduced cost and manufacturing lead time. (paper)

  8. Simultaneous measurement of thermal diffusivity and effusivity of solids using the flash technique in the front-face configuration

    International Nuclear Information System (INIS)

    Pech-May, Nelson Wilbur; Cifuentes, Ángel; Mendioroz, Arantza; Oleaga, Alberto; Salazar, Agustín

    2015-01-01

    Both thermal diffusivity and effusivity (or conductivity) are necessary to characterize the thermal transport properties of a material. The flash method is the most recognized procedure to measure the thermal diffusivity of free-standing opaque plates. However, it fails to simultaneously obtain the thermal effusivity (or conductivity). This is due to the difficulty of knowing the total energy absorbed by the sample surface after the light pulse. In this work, we propose using the flash method in the front-face configuration on a two-layer system made of the unknown plate and a fluid of known thermal properties. We demonstrate that the surface temperature is sensitive to the thermal mismatch between the plate and the fluid, which is governed by their thermal effusivity ratio. In order to verify the validity of the method and to establish its application limits we have performed flash measurements, using a pulsed laser and an infrared camera, on a set of calibrated materials (metals, alloys, ceramics and polymers) covering a wide range of thermal transport properties. These results confirm the ability of the flash method to simultaneously retrieve thermal diffusivity and effusivity in a fast manner in samples whose effusivities are lower than three times the effusivity of the liquid used as backing fluid. (paper)

  9. The development of alignment turning system for precision len cells

    Science.gov (United States)

    Huang, Chien-Yao; Ho, Cheng-Fang; Wang, Jung-Hsing; Chung, Chien-Kai; Chen, Jun-Cheng; Chang, Keng-Shou; Kuo, Ching-Hsiang; Hsu, Wei-Yao; Chen, Fong-Zhi

    2017-08-01

    In general, the drop-in and cell-mounted assembly are used for standard and high performance optical system respectively. The optical performance is limited by the residual centration error and position accuracy of the conventional assembly. Recently, the poker chip assembly with high precision lens barrels that can overcome the limitation of conventional assembly is widely applied to ultra-high performance optical system. ITRC also develops the poker chip assembly solution for high numerical aperture objective lenses and lithography projection lenses. In order to achieve high precision lens cell for poker chip assembly, an alignment turning system (ATS) is developed. The ATS includes measurement, alignment and turning modules. The measurement module including a non-contact displacement sensor and an autocollimator can measure centration errors of the top and the bottom surface of a lens respectively. The alignment module comprising tilt and translation stages can align the optical axis of the lens to the rotating axis of the vertical lathe. The key specifications of the ATS are maximum lens diameter, 400mm, and radial and axial runout of the rotary table < 2 μm. The cutting performances of the ATS are surface roughness Ra < 1 μm, flatness < 2 μm, and parallelism < 5 μm. After measurement, alignment and turning processes on our ATS, the centration error of a lens cell with 200mm in diameter can be controlled in 10 arcsec. This paper also presents the thermal expansion of the hydrostatic rotating table. A poker chip assembly lens cell with three sub-cells is accomplished with average transmission centration error in 12.45 arcsec by fresh technicians. The results show that ATS can achieve high assembly efficiency for precision optical systems.

  10. Compliance among soft contact lens wearers.

    Science.gov (United States)

    Kuzman, Tomislav; Kutija, Marija Barisić; Masnec, Sanja; Jandroković, Sonja; Mrazovac, Danijela; Jurisić, Darija; Skegro, Ivan; Kalauz, Miro; Kordić, Rajko

    2014-12-01

    Contact lens compliance is proven to be crucial for preventing lens wear-related complications because of the interdependence of the steps in lens care regime and their influence on lens system microbial contamination. Awareness of the patients' lens handling compliance as well as correct recognition of non-compliant behaviours is the basis for creating more targeted strategies for patient education. The aim of this study was to investigate compliance among soft contact lens (SCL) wearers in different aspects of lens care handling and wearing habits. In our research 50 asymptomatic lens wearers filled out a questionnaire containing demographic data, lens type, hygiene and wearing habits, lenses and lens care system replacement schedule and self-evaluation of contact lens handling hygiene. We established criteria of compliance according to available manufacturer's recommendations, prior literature and our clinical experience. Only 2 (4%) of patients were fully compliant SCL wearers. The most common non-compliant behaviours were insufficient lens solution soaking time (62%), followed by failure to daily exchange lens case solution and showering while wearing lenses. 44% of patients reported storing lenses in saline solution. Mean lens storage case replacement was 3.6 months, with up to 78% patients replacing lens case at least once in 3 months. Average grade in self evaluating level of compliance was very good (4 +/- 0.78) (from 1-poor level of hygiene to 5-great level of hygiene). Lens wearers who reported excessive daily lens wear and more than 10 years of lens wearing experience were also found to be less compliant with other lens system care procedures. (t = -2.99, df=47, p rate, self grading was relatively high. Therefore, these results indicate the need for patient education and encouragement of better lens wearing habits and all of the lens maintenance steps at each patient visit.

  11. Contact Lens-Related Eye Infections

    Science.gov (United States)

    ... Español Eye Health / Eye Health A-Z Contact Lens-Related Eye Infections Sections Contact Lens-Related Eye ... Six Steps to Avoid Contact Lens Infections Contact Lens-Related Eye Infections Leer en Español: Infecciones relacionadas ...

  12. 21 CFR 886.1375 - Bagolini lens.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Bagolini lens. 886.1375 Section 886.1375 Food and... OPHTHALMIC DEVICES Diagnostic Devices § 886.1375 Bagolini lens. (a) Identification. A Bagolini lens is a device that consists of a plane lens containing almost imperceptible striations that do not obscure...

  13. Straylight Measurements in Contact Lens Wear

    NARCIS (Netherlands)

    van der Meulen, Ivanka J. E.; Engelbrecht, Leonore A.; van Vliet, Johannes M. J.; Lapid-Gortzak, Ruth; Nieuwendaal, Carla P.; Mourits, Maarten P.; Schlingemann, Reinier O.; van den Berg, Thomas J. T. P.

    2010-01-01

    Purpose: (1) To quantify the effect of contact lens wear on straylight in rigid and soft contact lens wearers and (2) to relate findings to morphological changes and subjective complaints. Methods: Straylight was measured using the Oculus C-Quant during contact lens wear and after contact lens

  14. Athermal design and analysis of glass-plastic hybrid lens

    Science.gov (United States)

    Yang, Jian; Cen, Zhaofeng; Li, Xiaotong

    2018-01-01

    With the rapid development of security market, the glass-plastic hybrid lens has gradually become a choice for the special requirements like high imaging quality in a wide temperature range and low cost. The reduction of spherical aberration is achieved by using aspherical surface instead of increasing the number of lenses. Obviously, plastic aspherical lens plays a great role in the cost reduction. However, the hybrid lens has a priority issue, which is the large thermal coefficient of expansion of plastic, causing focus shift and seriously affecting the imaging quality, so the hybrid lens is highly sensitive to the change of temperature. To ensure the system operates normally in a wide temperature range, it is necessary to eliminate the influence of temperature on the hybrid lens system. A practical design method named the Athermal Material Map is summarized and verified by an athermal design example according to the design index. It includes the distribution of optical power and selection of glass or plastic. The design result shows that the optical system has excellent imaging quality at a wide temperature range from -20 ° to 70 °. The method of athermal design in this paper has generality which could apply to optical system with plastic aspherical surface.

  15. Immunohistochemical studies of lens crystallins in the dysgenetic lens (dyl) mutant mice

    NARCIS (Netherlands)

    Brahma, S.K.; Sanyal, S.

    1984-01-01

    The lens in the dyl mutant mice shows a persistent lens-ectodermal connection as well as degeneration and extrusion of lens materials after the initial differentiation of the fibres. Immunohistochemical investigation of the ontogeny of the lens crystallins in this developing mutant lens has been

  16. A technique for determining fast and thermal neutron flux densities in intense high-energy (8-30 MeV) photon fields

    International Nuclear Information System (INIS)

    Price, K.W.; Holeman, G.R.; Nath, R.

    1978-01-01

    A technique for measuring fast and thermal neutron fluxes in intense high-energy photon fields has been developed. Samples of phorphorous pentoxide are exposed to a mixed photon-neutron field. The irradiated samples are then dissolved in distilled water and their activation products are counted in a liquid scintillation spectrometer at 95-97% efficiency. The radioactive decay characteristics of the samples are then analyzed to determine fast and thermal neutron fluxes. Sensitivity of this neutron detector to high energy photons has been measured and found to be small. (author)

  17. Investigation of modified thin SnO2 layers treated by rapid thermal annealing by means of hollow cathode spectroscopy and AFM technique

    International Nuclear Information System (INIS)

    Djulgerova, R; Popova, L; Beshkov, G; Petrovic, Z Lju; Rakocevic, Z; Mihailov, V; Gencheva, V; Dohnalik, T

    2006-01-01

    By means of hollow cathode spectroscopy and atomic force microscopy the surface morphology and composition of SnO 2 thin film, modified with hexamethyldisilazane after rapid thermal annealing treatment (800-1200 deg. C), are investigated. Formation of crystalline structure is suggested at lower temperatures. Depolimerization, destruction and dehydration are developed at temperatures of 1200 deg. C. It is shown that the rapid thermal annealing treatment could modify both the surface morphology and the composition of the layer, thus changing the adsorption ability of the sensing layer. The results confirm the ability of hollow cathode emission spectroscopy for depth profiling of new materials especially combined with standard techniques

  18. 3D Inkjet Printed Helical Antenna with Integrated Lens

    KAUST Repository

    Farooqui, Muhammad Fahad

    2016-08-30

    The gain of an antenna can be enhanced through the integration of a lens, although this technique has traditionally been restricted to planar antennas due to fabrication limitations of standard manufacturing processes. Here, through a unique combination of 3D and 2D inkjet printing of dielectric and metallic inks respectively, we demonstrate a lens that has been monolithically integrated to a non-planar antenna (helix) for the first time. Antenna measurements show that the integration of a Fresnel lens enhances the gain of a 2-turn helix by around 4.6 dB, which provides a peak gain of about 12.9 dBi at 8.8 GHz. The 3-dB axial ratio (AR) bandwidth of the antenna with the lens is 5.5%. This work also reports the complete characterization of this new process in terms of minimum features sizes and achievable conductivities. Due to monolithic integration of the lens through a fully printed process, this antenna configuration offers high gain performance by using a low cost and rapid fabrication technique. © 2016 IEEE.

  19. Contact Lens Related Corneal Ulcer

    OpenAIRE

    Loh, KY; Agarwal, P

    2010-01-01

    A corneal ulcer caused by infection is one of the major causes of blindness worldwide. One of the recent health concerns is the increasing incidence of corneal ulcers associated with contact lens user especially if the users fail to follow specific instruction in using their contact lenses. Risk factors associated with increased risk of contact lens related corneal ulcers are: overnight wear, long duration of continuous wear, lower socio-economic classes, smoking, dry eye and poor hygiene. Th...

  20. Crystalline lens and refractive development.

    Science.gov (United States)

    Iribarren, Rafael

    2015-07-01

    Individual refractive errors usually change along lifespan. Most children are hyperopic in early life. This hyperopia is usually lost during growth years, leading to emmetropia in adults, but myopia also develops in children during school years or during early adult life. Those subjects who remain emmetropic are prone to have hyperopic shifts in middle life. And even later, at older ages, myopic shifts are developed with nuclear cataract. The eye grows from 15 mm in premature newborns to approximately 24 mm in early adult years, but, in most cases, refractions are maintained stable in a clustered distribution. This growth in axial length would represent a refractive change of more than 40 diopters, which is compensated by changes in corneal and lens powers. The process which maintains the balance between the ocular components of refraction during growth is still under study. As the lens power cannot be measured in vivo, but can only be calculated based on the other ocular components, there have not been many studies of lens power in humans. Yet, recent studies have confirmed that the lens loses power during growth in children, and that hyperopic and myopic shifts in adulthood may be also produced by changes in the lens. These studies in children and adults give a picture of the changing power of the lens along lifespan. Other recent studies about the growth of the lens and the complexity of its internal structure give clues about how these changes in lens power are produced along life. Copyright © 2015 Elsevier Ltd. All rights reserved.

  1. Single lens laser beam shaper

    Science.gov (United States)

    Liu, Chuyu [Newport News, VA; Zhang, Shukui [Yorktown, VA

    2011-10-04

    A single lens bullet-shaped laser beam shaper capable of redistributing an arbitrary beam profile into any desired output profile comprising a unitary lens comprising: a convex front input surface defining a focal point and a flat output portion at the focal point; and b) a cylindrical core portion having a flat input surface coincident with the flat output portion of the first input portion at the focal point and a convex rear output surface remote from the convex front input surface.

  2. A course in lens design

    CERN Document Server

    Velzel, Chris

    2014-01-01

    A Course in Lens Design is an instruction in the design of image-forming optical systems. It teaches how a satisfactory design can be obtained in a straightforward way. Theory is limited to a minimum, and used to support the practical design work. The book introduces geometrical optics, optical instruments and aberrations. It gives a description of the process of lens design and of the strategies used in this process. Half of its content is devoted to the design of sixteen types of lenses, described in detail from beginning to end. This book is different from most other books on lens design because it stresses the importance of the initial phases of the design process: (paraxial) lay-out and (thin-lens) pre-design. The argument for this change of accent is that in these phases much information can be obtained about the properties of the lens to be designed. This information can be used in later phases of the design. This makes A Course in Lens Design a useful self-study book, and a suitable basis for an intro...

  3. Evaluation of water-use efficiency in foxtail millet (Setaria italica) using visible-near infrared and thermal spectral sensing techniques.

    Science.gov (United States)

    Wang, Meng; Ellsworth, Patrick Z; Zhou, Jianfeng; Cousins, Asaph B; Sankaran, Sindhuja

    2016-05-15

    Water limitations decrease stomatal conductance (g(s)) and, in turn, photosynthetic rate (A(net)), resulting in decreased crop productivity. The current techniques for evaluating these physiological responses are limited to leaf-level measures acquired by measuring leaf-level gas exchange. In this regard, proximal sensing techniques can be a useful tool in studying plant biology as they can be used to acquire plant-level measures in a high-throughput manner. However, to confidently utilize the proximal sensing technique for high-throughput physiological monitoring, it is important to assess the relationship between plant physiological parameters and the sensor data. Therefore, in this study, the application of rapid sensing techniques based on thermal imaging and visual-near infrared spectroscopy for assessing water-use efficiency (WUE) in foxtail millet (Setaria italica (L.) P. Beauv) was evaluated. The visible-near infrared spectral reflectance (350-2500 nm) and thermal (7.5-14 µm) data were collected at regular intervals from well-watered and drought-stressed plants in combination with other leaf physiological parameters (transpiration rate-E, A(net), g(s), leaf carbon isotopic signature-δ(13)C(leaf), WUE). Partial least squares regression (PLSR) analysis was used to predict leaf physiological measures based on the spectral data. The PLSR modeling on the hyperspectral data yielded accurate and precise estimates of leaf E, gs, δ(13)C(leaf), and WUE with coefficient of determination in a range of 0.85-0.91. Additionally, significant differences in average leaf temperatures (~1°C) measured with a thermal camera were observed between well-watered plants and drought-stressed plants. In summary, the visible-near infrared reflectance data, and thermal images can be used as a potential rapid technique for evaluating plant physiological responses such as WUE. Copyright © 2016 Elsevier B.V. All rights reserved.

  4. Application of the thermal plasma technique in the treatment of stone surfaces; Aplicacion de la tecnica de plasmas termicos en el tratamiento de superficies petreas

    Energy Technology Data Exchange (ETDEWEB)

    Gonzalez A, Z I

    2000-07-01

    The stone materials which form part of the cultural heritage of Mexico, are degraded under the united action of water, atmospheric gases, air pollution, temperature changes and the microorganisms action; provoking on the stone: fissures, crevices, scalings, fragmentations, pulverizations, etc. Therefore, the purpose of this work is to study the possibilities to apply a protective coating on the stone surfaces, previously clean and consolidated, through the thermal plasma technique. The purpose is to analyse the physical and chemical properties of three types of stone materials: quarry, tezontle and chiluca, usually used in constructions of cultural interest such as: historical monuments, churches, sculptures, etc., before and after to be submitted to the action of thermal plasma in order to examine the feasibility in the use of this coating technique in this type of applications. The application of conventional techniques to determine: porosity, density, absorption, low pressure water absorption and crystallization by total immersion of nuclear techniques such as: neutron activation analysis, x-ray diffraction and scanning electron microscopy as well as of instrumental techniques: optical microscopy, mechanical assays of compression, flexure and surface area calculations, allowed to know the chemical and physical properties of the stone material before and after to be treated through the thermal plasma technique, projecting quartz on the stones surface at different distances and current intensity and showing the effect caused by the modifications or surface alterations present by cause of the application of that coating. the obtained results provide a general panorama of the application of this technique as an alternative to the maintenance of the architectural inheritance built in stone. (Author)

  5. Thermal and optical properties of polycrystalline CdS thin films deposited by the gradient recrystallization and growth (GREG) technique using photoacoustic methods

    International Nuclear Information System (INIS)

    Albor-Aguilera, M.L.; Gonzalez-Trujillo, M.A.; Cruz-Orea, A.; Tufino-Velazquez, M.

    2009-01-01

    In this work we report the study of the thermal and optical properties of polycrystalline CdS thin films deposited by the gradient recrystallization and growth technique. CdS films were grown on pyrex glass substrates. These studies were carried out using an open photoacoustic cell made out of an electret microphone. From X-ray diffraction, atomic force microscope and photoluminescence measurements we observed polycrystalline CdS films with good morphology and crystalline quality. We obtained a thermal diffusivity coefficient of our samples with values ranging from 3.15 to 3.89 x 10 -2 cm 2 /s. For comparison, we measured a value of 1.0 x 10 -2 cm 2 /s for the thermal diffusivity coefficient of a CdS single crystal. We measured an energy gap value of 2.42 eV for our samples by using a photoacoustic spectroscopy system

  6. Combination of thermal and electric properties' measurement techniques in a single setup suitable for radioactive materials in controlled environments and based on the 3ω approach

    Science.gov (United States)

    Shrestha, K.; Gofryk, K.

    2018-04-01

    We have designed and developed a new experimental setup, based on the 3ω method, to measure thermal conductivity, heat capacity, and electrical resistivity of a variety of samples in a broad temperature range (2-550 K) and under magnetic fields up to 9 T. The validity of this method is tested by measuring various types of metallic (copper, platinum, and constantan) and insulating (SiO2) materials, which have a wide range of thermal conductivity values (1-400 W m-1 K-1). We have successfully employed this technique for measuring the thermal conductivity of two actinide single crystals: uranium dioxide and uranium nitride. This new experimental approach for studying nuclear materials will help us to advance reactor fuel development and understanding. We have also shown that this experimental setup can be adapted to the Physical Property Measurement System (Quantum Design) environment and/or other cryocooler systems.

  7. Thermal conductivity prediction of nanoscale phononic crystal slabs using a hybrid lattice dynamics-continuum mechanics technique

    Directory of Open Access Journals (Sweden)

    Charles M. Reinke

    2011-12-01

    Full Text Available Recent work has demonstrated that nanostructuring of a semiconductor material to form a phononic crystal (PnC can significantly reduce its thermal conductivity. In this paper, we present a classical method that combines atomic-level information with the application of Bloch theory at the continuum level for the prediction of the thermal conductivity of finite-thickness PnCs with unit cells sized in the micron scale. Lattice dynamics calculations are done at the bulk material level, and the plane-wave expansion method is implemented at the macrosale PnC unit cell level. The combination of the lattice dynamics-based and continuum mechanics-based dispersion information is then used in the Callaway-Holland model to calculate the thermal transport properties of the PnC. We demonstrate that this hybrid approach provides both accurate and efficient predictions of the thermal conductivity.

  8. Influence of thermal gradient on gas turbine combustor wall using impingement/effusion cooling techniques: CHT CFD predictions

    Directory of Open Access Journals (Sweden)

    A. M. El-jummah

    2017-04-01

    Full Text Available Internal wall heat transfer relevant to impingement/effusion cooling techniques was investigated using conjugate heat transfer (CHT computational fluid dynamics (CFD with ANSYS Fluent and ICEM commercial software. This work concentrates on the development of CHT CFD design procedures that are applicable to combustor wall and turbine blade heat transfer optimisation in gas turbine (GT. It specifically modelled and compares two configuration which are specifically relevant to the impingement and effusion holes density n (m-2 and is the ratio of the hole pitch X2. The configurations investigated are equal and unequal impingement and effusion holes density n (m-2, respectively, whereby in each case the variation in the number of cooling holes were carried out. The ratio of impingement and effusion number of holes/m2 (or hole density n, investigated were impingement/effusion: 4306/4306 and 1076/4306, respectively. The geometries were for impingement wall, hole pitch X to diameter D, X/D ratio of ~ 11 but different number of holes N for both n geometries, at a constant offset effusion wall, hole X/D of 4.7 of the same N for both the two configurations. The model geometries have a constant impingement gap of 8 mm with both impingement and effusion walls at 6.35 mm thick Nimonic - 75 material and were computed for varied air mass flux G from 0.1 - 0.94 kg/sm2. Symmetrical applications were employed in modelling each of the geometry, whereby for the impingement hole, only quarter of one hole was modelled, while for the effusion side the holes were either quarter or half modelled. The two n geometries were computed with k - ɛ turbulence model using standard wall functions, which also applies to all G. The predicted locally surface X2 (or hole square area average heat transfer coefficient (HTC h values compared with with previously published experimental data showed good agreement. The reduced internal gap flow recirculation with reduced heat transfer to

  9. Analysis of the technique Thermal Desorption Spectroscopy (TDS) and its Application for the Characterization of Metal -Hydrogen Systems

    International Nuclear Information System (INIS)

    Castro, F.J.

    2000-01-01

    We present the theoretical and experimental developments made to study the desorption of hydrogen from metallic samples by Thermal Desorption Spectroscopy (TDS). With this technique gas desorption is stimulated by the programmed heating of the sample. To perform the study we set up a newly designed equipment and develop theoretical models of the kinetic processes involved. The equipment and the models are used to analyze the desorption process in a real system. We begin by analyzing the models developed to interpret the results of the experiments. These models consider simultaneously bulk diffusion and surface reaction processes in metal-hydrogen systems with one or two thermodynamic phases. We present numerical results, computer simulations and analytical approximations of the original models. Based on these results we analyze the main features of the spectra for the different relevant kinetic processes, and determine the changes induced in them when material parameters (activation energies, geometry) or experimental parameters (heating speed, initial concentration) are modified.We present the original equipment, designed and constructed during this work to perform the TDS experiments. We describe its main characteristics, its components, its range of operation and its sensibility. We also offer an analysis of the background spectrum. We use the Pd-H system to test the equipment and the models. The samples chosen, powders, granules, foils and wires, were previously characterized to analyze their composition, their morphology and their characteristic size. We show the results of Scanning Electron Microscopy (SEM) observation, X ray diffraction (XRD) and Auger Electron Spectroscopy (AES) analysis.We then present and analyze in depth the experimental desorption spectra of the palladium powder. Based on the analysis we determine the rate limiting step for desorption and the characteristic activation energies. When the system is on the b phase (hydride) the rate

  10. Assessment of thermal load reduction due to the application of simple passive techniques in a house office building at the south of Libya

    International Nuclear Information System (INIS)

    Domanski, Roman; Azzain, Gassem

    2006-01-01

    The assessment of possible reduction of heating and cooling requirements of 300 m 2 house-office building has been presented in this paper, when simple Thermal Passive Techniques (TPT) have been applied to building's construction in Sebha city at the Libyan south. The known software for dynamic simulation (TRNSYS) has been used as an environment of digital experimentation for this study. A prototype represents the building has been constructed with the help of the available model of single thermal zone of TRNSYS (Type 19). The built-in ASHREA Transfer Function Method within this model has been used to calculate the heat flux through building's materials. Primarily, the thermal load on building's construction without TPTs has been evaluated under weather conditions of a Typical Meteorological Year (TMY) of Sebha city. Then, the building has been equipped with simple TPTs (such as the control of building materials, insulation, shading, infiltration and ventilation with windows resizing). This building was subjected to the same weather conditions and again the thermal load has been evaluated in order to report the percentage of reduction of thermal load. The simulation has been conducted successfully, where good assessment of reduction of annual heating and cooling demands in the building has been obtained. It is proved that, about (46%) of annual heating load and (48%) of annual cooling load can be reduced if suitable simple TPTs were incorporated in buildings.(Author)

  11. Finite element modelling of radial lentotomy cuts to improve the accommodation performance of the human lens.

    Science.gov (United States)

    Burd, H J; Wilde, G S

    2016-04-01

    The use of a femtosecond laser to form planes of cavitation bubbles within the ocular lens has been proposed as a potential treatment for presbyopia. The intended purpose of these planes of cavitation bubbles (referred to in this paper as 'cutting planes') is to increase the compliance of the lens, with a consequential increase in the amplitude of accommodation. The current paper describes a computational modelling study, based on three-dimensional finite element analysis, to investigate the relationship between the geometric arrangement of the cutting planes and the resulting improvement in lens accommodation performance. The study is limited to radial cutting planes. The effectiveness of a variety of cutting plane geometries was investigated by means of modelling studies conducted on a 45-year human lens. The results obtained from the analyses depend on the particular modelling procedures that are employed. When the lens substance is modelled as an incompressible material, radial cutting planes are found to be ineffective. However, when a poroelastic model is employed for the lens substance, radial cuts are shown to cause an increase in the computed accommodation performance of the lens. In this case, radial cuts made in the peripheral regions of the lens have a relatively small influence on the accommodation performance of the lens; the lentotomy process is seen to be more effective when cuts are made near to the polar axis. When the lens substance is modelled as a poroelastic material, the computational results suggest that useful improvements in lens accommodation performance can be achieved, provided that the radial cuts are extended to the polar axis. Radial cuts are ineffective when the lens substance is modelled as an incompressible material. Significant challenges remain in developing a safe and effective surgical procedure based on this lentotomy technique.

  12. An Assessment of Polynomial Regression Techniques for the Relative Radiometric Normalization (RRN of High-Resolution Multi-Temporal Airborne Thermal Infrared (TIR Imagery

    Directory of Open Access Journals (Sweden)

    Mir Mustafizur Rahman

    2014-11-01

    Full Text Available Thermal Infrared (TIR remote sensing images of urban environments are increasingly available from airborne and satellite platforms. However, limited access to high-spatial resolution (H-res: ~1 m TIR satellite images requires the use of TIR airborne sensors for mapping large complex urban surfaces, especially at micro-scales. A critical limitation of such H-res mapping is the need to acquire a large scene composed of multiple flight lines and mosaic them together. This results in the same scene components (e.g., roads, buildings, green space and water exhibiting different temperatures in different flight lines. To mitigate these effects, linear relative radiometric normalization (RRN techniques are often applied. However, the Earth’s surface is composed of features whose thermal behaviour is characterized by complexity and non-linearity. Therefore, we hypothesize that non-linear RRN techniques should demonstrate increased radiometric agreement over similar linear techniques. To test this hypothesis, this paper evaluates four (linear and non-linear RRN techniques, including: (i histogram matching (HM; (ii pseudo-invariant feature-based polynomial regression (PIF_Poly; (iii no-change stratified random sample-based linear regression (NCSRS_Lin; and (iv no-change stratified random sample-based polynomial regression (NCSRS_Poly; two of which (ii and iv are newly proposed non-linear techniques. When applied over two adjacent flight lines (~70 km2 of TABI-1800 airborne data, visual and statistical results show that both new non-linear techniques improved radiometric agreement over the previously evaluated linear techniques, with the new fully-automated method, NCSRS-based polynomial regression, providing the highest improvement in radiometric agreement between the master and the slave images, at ~56%. This is ~5% higher than the best previously evaluated linear technique (NCSRS-based linear regression.

  13. An integral-field spectroscopic strong lens survey

    International Nuclear Information System (INIS)

    Bolton, Adam S; Burles, Scott

    2007-01-01

    We present the observational results of a survey for strong gravitational lens systems consisting of extended emission-line galaxies lensed by intervening early-type galaxies, conducted using integral field units (IFUs) of the Magellan IMACS and Gemini GMOS-N spectrographs. These data are highly valuable for corroborating the lensing interpretation of Hubble Space Telescope imaging data. We show that in many cases, ground-based IFU spectroscopy is in fact competitive with space-based imaging for the measurement of the mass model parameters of the lensing galaxy. We demonstrate a novel technique of three-dimensional gravitational lens modeling for a single lens system with a resolved lensed rotation curve. We also describe the details of our custom IFU data analysis software, which performs optimal multi-fiber extraction, relative and absolute wavelength calibration to a few hundredths of a pixel RMS and nearly Poisson-limited sky subtraction

  14. Projection model for flame chemiluminescence tomography based on lens imaging

    Science.gov (United States)

    Wan, Minggang; Zhuang, Jihui

    2018-04-01

    For flame chemiluminescence tomography (FCT) based on lens imaging, the projection model is essential because it formulates the mathematical relation between the flame projections captured by cameras and the chemiluminescence field, and, through this relation, the field is reconstructed. This work proposed the blurry-spot (BS) model, which takes more universal assumptions and has higher accuracy than the widely applied line-of-sight model. By combining the geometrical camera model and the thin-lens equation, the BS model takes into account perspective effect of the camera lens; by combining ray-tracing technique and Monte Carlo simulation, it also considers inhomogeneous distribution of captured radiance on the image plane. Performance of these two models in FCT was numerically compared, and results showed that using the BS model could lead to better reconstruction quality in wider application ranges.

  15. Pigment dispersion syndrome associated with spontaneous subluxation of crystalline lens

    Directory of Open Access Journals (Sweden)

    Vikas Veerwal

    2017-01-01

    Full Text Available Pigment dispersion syndrome (PDS is an ocular condition characterized by a dispersion of iris pigment throughout the eye. This pigment is deposited in a characteristic manner on the corneal endothelium as Krukenberg's spindle, anterior surface of the iris, in the trabecular meshwork, on the lens and zonule and occasionally on the anterior hyaloid face. Even with deposition of pigment on zonular fibers, no zonular weakness, or zonular dehiscence has been reported in these cases. We report a unique case of PDS with bilateral spontaneous subluxation of crystalline lens. With characteristic findings of pigment distribution in both his eyes, the patient had concave iris configuration with heavily pigmented trabecular meshwork confirming the diagnosis of PDS. The patient had bilateral 180° temporal subluxation of crystalline lens in both his eyes. The usual cause of lens subluxation such as Marfan's Syndrome and Ehler's Danlos Syndrome was ruled out. The patient underwent right eye followed by left eye intracapsular cataract extraction with ab-interno technique with postoperative best-corrected visual acuity (BCVA of 6/9 in both eyes. Spontaneous subluxation of crystalline lens in isolated PDS is not known to occur and has been reported by means of this case. We recommend a thorough assessment of zonular status in all cases of PDS.

  16. Pigment dispersion syndrome associated with spontaneous subluxation of crystalline lens.

    Science.gov (United States)

    Veerwal, Vikas; Goyal, Jawahar Lal; Jain, Parul; Arora, Ritu

    2017-01-01

    Pigment dispersion syndrome (PDS) is an ocular condition characterized by a dispersion of iris pigment throughout the eye. This pigment is deposited in a characteristic manner on the corneal endothelium as Krukenberg's spindle, anterior surface of the iris, in the trabecular meshwork, on the lens and zonule and occasionally on the anterior hyaloid face. Even with deposition of pigment on zonular fibers, no zonular weakness, or zonular dehiscence has been reported in these cases. We report a unique case of PDS with bilateral spontaneous subluxation of crystalline lens. With characteristic findings of pigment distribution in both his eyes, the patient had concave iris configuration with heavily pigmented trabecular meshwork confirming the diagnosis of PDS. The patient had bilateral 180° temporal subluxation of crystalline lens in both his eyes. The usual cause of lens subluxation such as Marfan's Syndrome and Ehler's Danlos Syndrome was ruled out. The patient underwent right eye followed by left eye intracapsular cataract extraction with ab-interno technique with postoperative best-corrected visual acuity (BCVA) of 6/9 in both eyes. Spontaneous subluxation of crystalline lens in isolated PDS is not known to occur and has been reported by means of this case. We recommend a thorough assessment of zonular status in all cases of PDS.

  17. Use of fusion-welding techniques in fabrication of a superconducting-magnet thermal-shield system

    International Nuclear Information System (INIS)

    Dalder, E.N.C.; Berkey, J.H.; Chang, Y.; Johnson, G.L.; Lathrop, G.H.; Podesta, D.L.; Van Sant, J.H.

    1983-01-01

    Success of the thermal shield system was demonstrated by the results of acceptance tests performed with the magnet and all its ancillary equipment. During these tests the thermal shield system was: (1) thermally cycled several times from 300 0 K to 77 0 K; (2) pressure cycled several times from 0 to 5 atmospheres; (3) operated for more than 500 hours at 77 0 K and in a vacuum environment of less than 10 - 5 torr; (4) operated in a magnetic field up to 6.0 Telsa; (5) exposed to a rapidly collapsing magnetic field of more than 250 gauss per second; (6) drained of all LN 2 in a few minutes, without any weld failures. The successful (and relatively problem free) operation of the magnet system validates the choice of the welding processes used, as well as their execution in both shop and field environments

  18. Total-Factor Energy Efficiency (TFEE Evaluation on Thermal Power Industry with DEA, Malmquist and Multiple Regression Techniques

    Directory of Open Access Journals (Sweden)

    Jin-Peng Liu

    2017-07-01

    Full Text Available Under the background of a new round of power market reform, realizing the goals of energy saving and emission reduction, reducing the coal consumption and ensuring the sustainable development are the key issues for thermal power industry. With the biggest economy and energy consumption scales in the world, China should promote the energy efficiency of thermal power industry to solve these problems. Therefore, from multiple perspectives, the factors influential to the energy efficiency of thermal power industry were identified. Based on the economic, social and environmental factors, a combination model with Data Envelopment Analysis (DEA and Malmquist index was constructed to evaluate the total-factor energy efficiency (TFEE in thermal power industry. With the empirical studies from national and provincial levels, the TFEE index can be factorized into the technical efficiency index (TECH, the technical progress index (TPCH, the pure efficiency index (PECH and the scale efficiency index (SECH. The analysis showed that the TFEE was mainly determined by TECH and PECH. Meanwhile, by panel data regression model, unit coal consumption, talents and government supervision were selected as important indexes to have positive effects on TFEE in thermal power industry. In addition, the negative indexes, such as energy price and installed capacity, were also analyzed to control their undesired effects. Finally, considering the analysis results, measures for improving energy efficiency of thermal power industry were discussed widely, such as strengthening technology research and design (R&D, enforcing pollutant and emission reduction, distributing capital and labor rationally and improving the government supervision. Relative study results and suggestions can provide references for Chinese government and enterprises to enhance the energy efficiency level.

  19. Design and high-volume manufacture of low-cost molded IR aspheres for personal thermal imaging devices

    Science.gov (United States)

    Zelazny, A. L.; Walsh, K. F.; Deegan, J. P.; Bundschuh, B.; Patton, E. K.

    2015-05-01

    The demand for infrared optical elements, particularly those made of chalcogenide materials, is rapidly increasing as thermal imaging becomes affordable to the consumer. The use of these materials in conjunction with established lens manufacturing techniques presents unique challenges relative to the cost sensitive nature of this new market. We explore the process from design to manufacture, and discuss the technical challenges involved. Additionally, facets of the development process including manufacturing logistics, packaging, supply chain management, and qualification are discussed.

  20. Tinting of intraocular lens implants

    Energy Technology Data Exchange (ETDEWEB)

    Zigman, S.

    1982-06-01

    Intraocular lens (IOL) implants of polymethyl methacrylate (PMMA) lack an important yellow pigment useful as a filter in the visual process and in the protection of the retina from short-wavelength radiant energy. The ability to produce a yellow pigment in the PMMA used in IOL implants by exposure to near-ultraviolet (UV) light was tested. It was found that the highly cross-linked material in Copeland lens blanks was tinted slightly because of this exposure. The absorptive properties of lens blanks treated with near-UV light in this way approached that of the absorptive properties of human lenses. This finding shows that it is possible to alter IOL implants simply so as to induce a pale-yellow pigment in them to improve the visual process and to protect the retinas of IOL users.

  1. Tinting of intraocular lens implants

    International Nuclear Information System (INIS)

    Zigman, S.

    1982-01-01

    Intraocular lens (IOL) implants of polymethyl methacrylate (PMMA) lack an important yellow pigment useful as a filter in the visual process and in the protection of the retina from short-wavelength radiant energy. The ability to produce a yellow pigment in the PMMA used in IOL implants by exposure to near-ultraviolet (UV) light was tested. It was found that the highly cross-linked material in Copeland lens blanks was tinted slightly because of this exposure. The absorptive properties of lens blanks treated with near-UV light in this way approached that of the absorptive properties of human lenses. This finding shows that it is possible to alter IOL implants simply so as to induce a pale-yellow pigment in them to improve the visual process and to protect the retinas of IOL users

  2. Automated Fresnel lens tester system

    Energy Technology Data Exchange (ETDEWEB)

    Phipps, G.S.

    1981-07-01

    An automated data collection system controlled by a desktop computer has been developed for testing Fresnel concentrators (lenses) intended for solar energy applications. The system maps the two-dimensional irradiance pattern (image) formed in a plane parallel to the lens, whereas the lens and detector assembly track the sun. A point detector silicon diode (0.5-mm-dia active area) measures the irradiance at each point of an operator-defined rectilinear grid of data positions. Comparison with a second detector measuring solar insolation levels results in solar concentration ratios over the image plane. Summation of image plane energies allows calculation of lens efficiencies for various solar cell sizes. Various graphical plots of concentration ratio data help to visualize energy distribution patterns.

  3. Chemical performance of multi-environment trials in lens (Lens culinaris M.).

    Science.gov (United States)

    Karadavut, Ufuk; Palta, Cetin

    2010-01-15

    Genotype-environment (GE) interaction has been a major effect to determine stable lens (Lens culinaris (Medik.) Merr.) cultivars for chemical composition in Turkey. Utilization of the lines depends on their agronomic traits and stability of the chemical composition in diverse environments. The objectives of this study were: (i) to evaluate the influence of year and location on the chemical composition of lens genotypes; and (ii) to determine which cultivar is the most stable. Genotypes were evaluated over 3 years (2005, 2006 and 2007) at four locations in Turkey. Effects of year had the largest impact on all protein contents. GE interaction was analyzed by using linear regression techniques. Stability was estimated using the Eberhart and Russell method. 'Kişlik Kirmizi51' was the most stable cultivar for grain yield. The highest protein was obtained from 'Kişlik Kirmizi51' (4.6%) across environments. According to stability analysis, 'Firat 87' had the most stable chemical composition. This genotype had a regression coefficient (b(i) = 1) around unity, and deviations from regression values (delta(ij) = 0) around zero. Chemical composition was affected by year in this study. Temperature might have an effect on protein, oil, carbohydrate, fibre and ash. Firat 87 could be recommended for favourable environments. Copyright (c) 2009 Society of Chemical Industry.

  4. Spectral analysis and comparison of mineral deposits forming in opacified intraocular lens and senile cataractous lens

    Science.gov (United States)

    Lin, Shan-Yang; Chen, Ko-Hwa; Lin, Chih-Cheng; Cheng, Wen-Ting; Li, Mei-Jane

    2010-10-01

    This preliminary report was attempted to compare the chemical components of mineral deposits on the surfaces of an opacified intraocular lens (IOL) and a calcified senile cataractous lens (SCL) by vibrational spectral diagnosis. An opacified intraocular lens (IOL) was obtained from a 65-year-old male patient who had a significant decrease in visual acuity 2-years after an ocular IOL implantation. Another SCL with grayish white calcified plaque on the subcapsular cortex was isolated from a 79-year-old male patient with complicated cataract after cataract surgery. Optical light microscope was used to observe both samples and gross pictures were taken. Fourier transform infrared (FT-IR) and Raman microspectroscopic techniques were employed to analyze the calcified deposits. The curve-fitting algorithm using the Gaussian function was also used to quantitatively estimate the chemical components in each deposit. The preliminary results of spectral diagnosis indicate that the opacified IOL mainly consisted of the poorly crystalline, immature non-stoichiometric hydroxyapatite (HA) with higher content of type B carbonated apatites. However, the calcified plaque deposited on the SCL was comprised of a mature crystalline stoichiometric HA having higher contents of type A and type B carbonate apatites. More case studies should be examined in future.

  5. Enhanced mechanical and thermal properties of polystyrene nanocomposites prepared using organo-functionalized NiAl layered double hydroxide via melt intercalation technique

    Directory of Open Access Journals (Sweden)

    Kelothu Suresh

    2017-06-01

    Full Text Available The article reports upon the preparation and characterization of organo-functionalized NiAl layered double hydroxide (LDH-polystyrene (PS nanocomposites. Initially, pristine NiAl LDH was synthesized via the co-precipitation technique and was subsequently treated using sodium dodecyl sulfate to obtain organo-functionalized NiAl LDH (ONiAl LDH. PS nanocomposites were fabricated by melt intercalation using a twin screw extruder in presence of ONiAl LDH nanofiller (1, 3, 5, and 7 wt.%. The PS nanocomposites were characterized for their structural, thermal and mechanical properties. The dispersion and morphology of the obtained PS nanocomposites were investigated by X-ray diffraction (XRD and transmission electron microscopy (TEM. Mechanical and thermal properties of the PS nanocomposites as a function of LDH content were examined by tensile tests, thermogravimetric analysis (TGA and differential scanning calorimetry (DSC. The XRD and TEM results revealed the formation of an exfoliated structure of the PS nanocomposite with 1 wt.% ONiAl LDH loading. The maximum improvements of the mechanical and thermal properties of the nanocomposites with ONiAl LDH loading over pristine PS included tensile strength = 34.5% (1 wt.%, thermal decomposition temperatures (T15% = 27.4 °C (7 wt.%, and glass transition temperature (Tg = 4.3 °C (7 wt.%. The PS nanocomposites possessed higher mechanical strength and thermal degradation resistance compared to the pristine PS. The activation energy (Ea and reaction mechanism with respect to thermal degradation of the pristine PS and its nanocomposites were evaluated by the Coats-Redfern and Criado model, respectively.

  6. An Alternative Approach to Mapping Thermophysical Units from Martian Thermal Inertia and Albedo Data Using a Combination of Unsupervised Classification Techniques

    Directory of Open Access Journals (Sweden)

    Eriita Jones

    2014-06-01

    Full Text Available Thermal inertia and albedo provide information on the distribution of surface materials on Mars. These parameters have been mapped globally on Mars by the Thermal Emission Spectrometer (TES onboard the Mars Global Surveyor. Two-dimensional clusters of thermal inertia and albedo reflect the thermophysical attributes of the dominant materials on the surface. In this paper three automated, non-deterministic, algorithmic classification methods are employed for defining thermophysical units: Expectation Maximisation of a Gaussian Mixture Model; Iterative Self-Organizing Data Analysis Technique (ISODATA; and Maximum Likelihood. We analyse the behaviour of the thermophysical classes resulting from the three classifiers, operating on the 2007 TES thermal inertia and albedo datasets. Producing a rigorous mapping of thermophysical classes at ~3 km/pixel resolution remains important for constraining the geologic processes that have shaped the Martian surface on a regional scale, and for choosing appropriate landing sites. The results from applying these algorithms are compared to geologic maps, surface data from lander missions, features derived from imaging, and previous classifications of thermophysical units which utilized manual (and potentially more time consuming classification methods. These comparisons comprise data suitable for validation of our classifications. Our work shows that a combination of the algorithms—ISODATA and Maximum Likelihood—optimises the sensitivity to the underlying dataspace, and that new information on Martian surface materials can be obtained by using these methods. We demonstrate that the algorithms used here can be applied to define a finer partitioning of albedo and thermal inertia for a more detailed mapping of surface materials, grain sizes and thermal behaviour of the Martian surface and shallow subsurface, at the ~3 km scale.

  7. Optimized lens-sparing treatment of retinoblastoma with electron beams

    International Nuclear Information System (INIS)

    Steenbakkers, Roel J.H.M.; Altschuler, Martin D.; D'Angio, Giulio J.; Goldwein, Joel W.; Kassaee, Alireza

    1997-01-01

    Purpose: The ideal lens-sparing radiotherapy technique for retinoblastoma calls for 100% dose to the entire retina including the ora serrata and zero dose to the lens. Published techniques, most of which use photons, have not accomplished this ideal treatment. We describe here a technique that approaches this ideal configuration using electron beam therapy. Methods and Materials: Dose-modeling calculations were made using a computer program built around a proprietary algorithm. This program calculates 3D dose distribution for electrons and photons and uses the Cimmino feasibility method for the inverse problem of beam weighting to achieve the prescribed dose. The algorithm has been verified in the ocular region by measurements in a RANDO phantom. To search for an ideal lens-sparing beam setup, a stylized phantom of an 8-month-old infant was generated with built-in inhomogeneities, and a phantom of a 5-year-old child was generated from a patient CT series. Results: Of more than 100 different beam setups tested, two 9 MeV electron beams at gantry angles plus and minus 26 degrees from the optic nerve axis achieved the best distribution. Both fields have a lens block and an isocenter between the globe and origin of the optic nerve. When equal doses are given to both fields, the entire extent of the retina (including ora serrata) received 100%, while the lens received 10% or less. Conclusion: The two-oblique-electron-beam technique here described appears to meet most of the stringent dosimetry needed to treat retinoblastoma. It is suitable for a range of ages, from infancy to early childhood years

  8. Theoretical description of the photopyroelectric technique in the slanted detector configuration for thermal diffusivity measurements in fluids

    International Nuclear Information System (INIS)

    Rojas-Trigos, J.B.; Marín, E.; Mansanares, A.M.; Cedeño, E.; Juárez-Gracia, G.; Calderón, A.

    2014-01-01

    Highlights: • A model for photopyroelectric thermal characterization of fluids is presented. • A slanted detector configuration is considered with a finite measurement cell. • The mean temperature distribution in the photopyroelectric detector, as function of the beam spot position, is calculated. • The influence of the excitation beam spot size, the thermal diffusion length and size of the sample is discussed. • The high lateral resolution of the method observed in experiments is explain. - Abstract: This work presents an extended description about the theoretical aspects related to the generation of the photopyroelectric signal in a recently proposed wedge-like heat transmission detection configuration, which recreates the well-known Angstrom method (widely used for solid samples) for accurate thermal diffusivity measurement in gases and liquids. The presented model allows for the calculation of the temperature profile detected by the pyroelectric sensor as a function of the excitation beam position, and the study of the influence on it of several parameters, such as spot size, thermal properties of the absorber layer, and geometrical parameters of the measurement cell. Through computer simulations, it has been demonstrated that a narrow temperature distribution is created at the sensor surface, independently of the lateral diffusion of heat taking place at the sample's surface

  9. Low thermal budget annealing technique for high performance amorphous In-Ga-ZnO thin film transistors

    Directory of Open Access Journals (Sweden)

    Joong-Won Shin

    2017-07-01

    Full Text Available In this paper, we investigate a low thermal budget post-deposition-annealing (PDA process for amorphous In-Ga-ZnO (a-IGZO oxide semiconductor thin-film-transistors (TFTs. To evaluate the electrical characteristics and reliability of the TFTs after the PDA process, microwave annealing (MWA and rapid thermal annealing (RTA methods were applied, and the results were compared with those of the conventional annealing (CTA method. The a-IGZO TFTs fabricated with as-deposited films exhibited poor electrical characteristics; however, their characteristics were improved by the proposed PDA process. The CTA-treated TFTs had excellent electrical properties and stability, but the CTA method required high temperatures and long processing times. In contrast, the fabricated RTA-treated TFTs benefited from the lower thermal budget due to the short process time; however, they exhibited poor stability. The MWA method uses a low temperature (100 °C and short annealing time (2 min because microwaves transfer energy directly to the substrate, and this method effectively removed the defects in the a-IGZO TFTs. Consequently, they had a higher mobility, higher on-off current ratio, lower hysteresis voltage, lower subthreshold swing, and higher interface trap density than TFTs treated with CTA or RTA, and exhibited excellent stability. Based on these results, low thermal budget MWA is a promising technology for use on various substrates in next generation displays.

  10. Low thermal budget annealing technique for high performance amorphous In-Ga-ZnO thin film transistors

    Science.gov (United States)

    Shin, Joong-Won; Cho, Won-Ju

    2017-07-01

    In this paper, we investigate a low thermal budget post-deposition-annealing (PDA) process for amorphous In-Ga-ZnO (a-IGZO) oxide semiconductor thin-film-transistors (TFTs). To evaluate the electrical characteristics and reliability of the TFTs after the PDA process, microwave annealing (MWA) and rapid thermal annealing (RTA) methods were applied, and the results were compared with those of the conventional annealing (CTA) method. The a-IGZO TFTs fabricated with as-deposited films exhibited poor electrical characteristics; however, their characteristics were improved by the proposed PDA process. The CTA-treated TFTs had excellent electrical properties and stability, but the CTA method required high temperatures and long processing times. In contrast, the fabricated RTA-treated TFTs benefited from the lower thermal budget due to the short process time; however, they exhibited poor stability. The MWA method uses a low temperature (100 °C) and short annealing time (2 min) because microwaves transfer energy directly to the substrate, and this method effectively removed the defects in the a-IGZO TFTs. Consequently, they had a higher mobility, higher on-off current ratio, lower hysteresis voltage, lower subthreshold swing, and higher interface trap density than TFTs treated with CTA or RTA, and exhibited excellent stability. Based on these results, low thermal budget MWA is a promising technology for use on various substrates in next generation displays.

  11. Lens system for SIMS analysis

    International Nuclear Information System (INIS)

    Martinez, G.; Sancho, M.; Garcia-Galan, J.C.

    1987-01-01

    A powerful version of the charge-density method is applied to the study of a combined objective and emission lens, suitable for highly localized analysis of a flat sample surface. This lens can extract secondary ions of equal or opposite polarity to that of the primary particles. A computer simulation of the ion trajectories for both modes is made. The behaviour for different values of the geometric parameters and polarizations is analyzed and useful data for design such as primary beam demagnification and secondary image position are given. (author) 4 refs

  12. An Investigation of an Irradiated Fuel Pin by Measurement of the Production of Fast Neutrons in a Thermal Column and by Pile Oscillation Technique

    Energy Technology Data Exchange (ETDEWEB)

    Gustavsson, Veine

    1968-05-15

    A fuel pin irradiated to about 3400 MWd/tU from the Halden reactor has been investigated by a measurement of the production of fast neutrons in a thermal column and by pile oscillator technique in the central channel of the reactor R1. Calibration was made by using samples with different U 235 enrichments. The thermal column experiment gives the quantity ave({nu}{sigma}{sub f}) (average in the thermal column spectrum) for the Halden sample. {sigma}{sub f} is the macroscopic fission cross section and {nu} is the number of fast neutrons produced per fission. The result of the oscillator measurements is a value of ave({sigma}{sub a}) - w ave({sigma}{sub f}) (average in the central channel spectrum) for the irradiated sample, w is the importance of a fast neutron relative to a thermal one and ave({sigma}{sub a}) is the macroscopic absorption cross section. The results from both the experiments have been compared with values calculated by the REBUS code and the agreement was good.

  13. Tribological Behavior of Thermal Spray Coatings, Deposited by HVOF and APS Techniques, and Composite Electrodeposits Ni/SiC at Both Room Temperature and 300 °C

    Directory of Open Access Journals (Sweden)

    A. Lanzutti

    2013-06-01

    Full Text Available The Both the thermal spray and the electroplating coatings are widely used because of their high wear resistance combined with good corrosion resistance. In particular the addition of both micro particles or nano‐particles to the electro deposited coatings could lead to an increase of the mechanical properties, caused by the change of the coating microstructure. The thermal spray coatings were deposited following industrial standards procedures, while the Ni/SiC composite coatings were produced at laboratory scale using both micro‐and nano‐sized ceramic particles. All the produced coatings were characterized regarding their microstructure,mechanical properties and the wear resistance. The tribological properties were analyzed using a tribometer under ball on disk configuration at both room temperature and 300oC. The results showed that the cermet thermal spray coatings have a high wear resistance, while the Ni nano‐composite showed good anti wear properties compared to the harder ceramic/cermet coatings deposited by thermal spray technique.

  14. An Investigation of an Irradiated Fuel Pin by Measurement of the Production of Fast Neutrons in a Thermal Column and by Pile Oscillation Technique

    International Nuclear Information System (INIS)

    Gustavsson, Veine

    1968-05-01

    A fuel pin irradiated to about 3400 MWd/tU from the Halden reactor has been investigated by a measurement of the production of fast neutrons in a thermal column and by pile oscillator technique in the central channel of the reactor R1. Calibration was made by using samples with different U 235 enrichments. The thermal column experiment gives the quantity ave(νΣ f ) (average in the thermal column spectrum) for the Halden sample. Σ f is the macroscopic fission cross section and ν is the number of fast neutrons produced per fission. The result of the oscillator measurements is a value of ave(Σ a ) - w ave(Σ f ) (average in the central channel spectrum) for the irradiated sample, w is the importance of a fast neutron relative to a thermal one and ave(Σ a ) is the macroscopic absorption cross section. The results from both the experiments have been compared with values calculated by the REBUS code and the agreement was good

  15. Intravitreal Phacoemulsification Using Torsional Handpiece for Retained Lens Fragments

    Science.gov (United States)

    Kumar, Vinod; Takkar, Brijesh

    2016-01-01

    Purpose: To evaluate the results of intravitreal phacoemulsification with torsional hand piece in eyes with posteriorly dislocated lens fragments. Methods: In this prospective, interventional case series, 15 eyes with retained lens fragments following phacoemulsification were included. All patients underwent standard three-port pars plana vitrectomy and intravitreal phacoemulsification using sleeveless, torsional hand piece (OZiL™, Alcon's Infiniti Vision System). Patients were followed up for a minimum of six months to evaluate the visual outcomes and complications. Results: The preoperative best-corrected visual acuity (BCVA) ranged from light perception to 0.3. No complications such as thermal burns of the scleral wound, retinal damage due to flying lens fragments, or difficult lens aspiration occurred during intravitreal phacoemulsification. Mean post-operative BCVA at the final follow-up was 0.5. Two eyes developed cystoid macular edema, which was managed medically. No retinal detachment was noted. Conclusion: Intravitreal phacoemulsification using torsional hand piece is a safe and effective alternative to conventional longitudinal phacofragmentation. PMID:27621783

  16. Micro/nanosized refractive lens arrays formed by means of conformal thin film deposition

    International Nuclear Information System (INIS)

    Zeng Hongjun; Lajos, Robert; Elzy, Ed; Metlushko, Vitali

    2008-01-01

    We provide a 'growing' method for fabricating a microlens array with lateral size of a few microns or less. Instead of using complicated etching techniques, the method forms a spherical profile of the lens using conformal chemical vapor deposition. We have fabricated two lens arrays. One has a pitch of 1200 nm, a circular aperture 1000 nm in diameter and a sag height of 130 nm. The other array has a pitch of 600 nm, and a square aperture of 600 nm x 600 nm, with a fill factor close to 100%. The maximum profile deviation between the fabricated lens and an ideal sphere is about 11% and 14% respectively. The calculation indicates that the curvature difference of the profile of the square lens in the orthogonal and diagonal direction is 5.5%. The roughness of the lens is measured as approximately 6 nm

  17. Refractive lens exchange with a multifocal diffractive aspheric intraocular lens

    Directory of Open Access Journals (Sweden)

    Teresa Ferrer-Blasco

    2012-06-01

    Full Text Available PURPOSE: To evaluate the safety, efficacy and predictability after refractive lens exchange with multifocal diffractive aspheric intraocular lens implantation. METHODS: Sixty eyes of 30 patients underwent bilateral implantation with AcrySof® ReSTOR® SN6AD3 intraocular lens with +4.00 D near addition. Patients were divided into myopic and hyperopic groups. Monocular best corrected visual acuity at distance and near and monocular uncorrected visual acuity at distance and near were measured before and 6 months postoperatively. RESULTS: After surgery, uncorrected visual acuity was 0.08 ± 0.15 and 0.11 ± 0.14 logMAR for the myopic and hyperopic groups, respectively (50% and 46.67% of patients had an uncorrected visual acuity of 20/20 or better in the myopic and hyperopic groups, respectively. The safety and efficacy indexes were 1.05 and 0.88 for the myopic and 1.01 and 0.86 for the hyperopic groups at distance vision. Within the myopic group, 20 eyes remained unchanged after the surgery, and 3 gained >2 lines of best corrected visual acuity. For the hyperopic group, 2 eyes lost 2 lines of best corrected visual acuity, 21 did not change, and 3 eyes gained 2 lines. At near vision, the safety and efficacy indexes were 1.23 and 1.17 for the myopic and 1.16 and 1.13 for the hyperopic groups. Best corrected near visual acuity improved after surgery in both groups (from 0.10 logMAR to 0.01 logMAR in the myopic group, and from 0.10 logMAR to 0.04 logMAR in the hyperopic group. CONCLUSIONS: The ReSTOR® SN6AD3 intraocular lens in refractive lens exchange demonstrated good safety, efficacy, and predictability in correcting high ametropia and presbyopia.

  18. Stretchable Binary Fresnel Lens for Focus Tuning

    NARCIS (Netherlands)

    Li, X.; Wei, L.; Poelma, R.H.; Vollebregt, S.; Wei, J.; Urbach, Paul; Sarro, P.M.; Zhang, G.Q.

    2016-01-01

    This paper presents a tuneable binary amplitude Fresnel lens produced by wafer-level microfabrication. The Fresnel lens is fabricated by encapsulating lithographically defined vertically aligned carbon nanotube (CNT) bundles inside a polydimethyl-siloxane (PDMS) layer. The composite lens material

  19. 21 CFR 886.1400 - Maddox lens.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Maddox lens. 886.1400 Section 886.1400 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES OPHTHALMIC DEVICES Diagnostic Devices § 886.1400 Maddox lens. (a) Identification. A Maddox lens is a device...

  20. Crystalline lens power and refractive error.

    Science.gov (United States)

    Iribarren, Rafael; Morgan, Ian G; Nangia, Vinay; Jonas, Jost B

    2012-02-01

    To study the relationships between the refractive power of the crystalline lens, overall refractive error of the eye, and degree of nuclear cataract. All phakic participants of the population-based Central India Eye and Medical Study with an age of 50+ years were included. Calculation of the refractive lens power was based on distance noncycloplegic refractive error, corneal refractive power, anterior chamber depth, lens thickness, and axial length according to Bennett's formula. The study included 1885 subjects. Mean refractive lens power was 25.5 ± 3.0 D (range, 13.9-36.6). After adjustment for age and sex, the standardized correlation coefficients (β) of the association with the ocular refractive error were highest for crystalline lens power (β = -0.41; P lens opacity grade (β = -0.42; P lens power (β = -0.95), lower corneal refractive power (β = -0.76), higher lens thickness (β = 0.30), deeper anterior chamber (β = 0.28), and less marked nuclear lens opacity (β = -0.05). Lens thickness was significantly lower in eyes with greater nuclear opacity. Variations in refractive error in adults aged 50+ years were mostly influenced by variations in axial length and in crystalline lens refractive power, followed by variations in corneal refractive power, and, to a minor degree, by variations in lens thickness and anterior chamber depth.

  1. 21 CFR 886.3600 - Intraocular lens.

    Science.gov (United States)

    2010-04-01

    ... DEVICES OPHTHALMIC DEVICES Prosthetic Devices § 886.3600 Intraocular lens. (a) Identification. An intraocular lens is a device made of materials such as glass or plastic intended to be implanted to replace the natural lens of an eye. (b) Classification. Class III. (c) Date PMA or notice of completion of a...

  2. Use of Several Thermal Analysis Techniques to Study the Cracking of a Nitrile Butadiene Rubber (NBR) Insulator on the Booster Separation Motor (BSM) of the Space Shuttle

    Science.gov (United States)

    Wingard, Charles D.

    1999-01-01

    Two different vendor rubber formulations have been used to produce the silica-filled NBR insulators for the BSM of each of the two Solid Rocket Boosters (SRBs) on the Space Shuttle. Each cured insulator is bonded to the BSM aluminum aft closure with an epoxy adhesive, and some of the curved areas in the rubber may have significant residual stresses. A number of recently bonded NBR insulators have shown fine surface cracks, and stressed insulator areas may be aging at a faster rate than unstressed areas, thus hastening the surface cracking. Thermal analysis data on both vendor insulators by Dynamic Mechanical Analysis (DMA) through a temperature/frequency sweep from 24 to 74 C have shown a higher flexural storage modulus and Arrhenius activation energy for the stressed area than for the unstressed area. Other thermal analysis techniques are being used to study the insulator surface vs. bulk interior for better understanding this anomaly.

  3. Improved Ohmic-contact to AlGaN/GaN using Ohmic region recesses by self-terminating thermal oxidation assisted wet etching technique

    Science.gov (United States)

    Liu, J.; Wang, J.; Wang, H.; Zhu, L.; Wu, W.

    2017-06-01

    Lower Ti/Al/Ni/Au Ohmic contact resistance on AlGaN/GaN with wider rapid thermal annealing (RTA) temperature window was achieved using recessed Ohmic contact structure based on self-terminating thermal oxidation assisted wet etching technique (STOAWET), in comparison with conventional Ohmic contacts. Even at lower temperature such as 650°C, recessed structure by STOAWET could still obtain Ohmic contact with contact resistance of 1.97Ω·mm, while conventional Ohmic structure mainly featured as Schottky contact. Actually, both Ohmic contact recess and mesa isolation processes could be accomplished by STOAWET in one process step and the process window of STOAWET is wide, simplifying AlGaN/GaN HEMT device process. Our experiment shows that the isolation leakage current by STOAWET is about one order of magnitude lower than that by inductivity coupled plasma (ICP) performed on the same wafer.

  4. Characterization of the anaerobic digestion of thermal pre-treated slaughterhouse waste by applying new IR techniques

    OpenAIRE

    Rodríguez-Abalde, Ángela; Gómez, X.; Blanco, D.; Cuetos, María José; Flotats Ripoll, Xavier; Fernández, B.

    2013-01-01

    In this work, thermal analysis and infrared spectrometry were used to explain the behaviour of two different pasteurized animal by-products with different protein/fat/carbohydrate composition. The presence of hardly degradable nitrogen containing components, identified by infrared spectrometry, and produced during Maillard reactions at pasteurization temperature, explained the different behaviour (methane rate and yield) under anaerobic conditions of pig and poultry wastes

  5. Dosimetry techniques of thermal neutrons and {gamma} radiation in reactor cores; Techniques de dosimetrie des neutrons thermiques et du rayonnement {gamma} dans les piles

    Energy Technology Data Exchange (ETDEWEB)

    Sutton, J; Draganic, I; Hering, H [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1955-07-01

    Chemical studies under radiation done in the reactor cores require to be followed by dosimetry. When the irradiations are done in the reflector, one can limit to the measure of the {gamma} and the neutron radiation. For the dosimetry of the {gamma} radiation, a dosimeter of ferrous sulfate is convenient until doses of about 10{sup 6} rep. The use of aired oxalic acid solutions permits to reach 10{sup 7} rep. The dosimetry of thermal neutrons has been made with solutions of cobalt sulphate or paper filter impregnated with this salt. The total chemical effect of the {gamma} and of the slow neutrons radiation is obtained with solutions of ferrous sulfate added with lithium sulphate. (M.B.) [French] Les etudes de chimie sous radiation faites dans les piles exigent d'etre suivies par dosimetrie. Lorsque les irradiations sont effectues dans le reflecteur, on peut se limiter a doser le rayonnement {gamma} et les neutrons. Pour la dosimetrie du rayonnement {gamma}, un dosimetre a sulfate ferreux convient jusqu'a des doses d'environ 10{sup 6} rep. L'emploi de solutions aerees d'acide oxalique permet d'atteindre 10{sup 7} rep. La dosimetrie des neutrons thermiques a ete faite avec des solutions de sulfate de cotalt ou du papier filtre impregne de ce sel. L'effet chimique total du rayonnement {gamma} et des neutrons lents est obtenu avec des solutions de sulfate ferreux additionne de sulfate de lithium. (M.B.)

  6. Efficient generation of lens progenitor cells from cataract patient-specific induced pluripotent stem cells.

    Directory of Open Access Journals (Sweden)

    Xiaodi Qiu

    Full Text Available The development of a technique to induce the transformation of somatic cells to a pluripotent state via the ectopic expression of defined transcription factors was a transformational event in the field of regenerative medicine. The development of this technique also impacted ophthalmology, as patient-specific induced pluripotent stemcells (iPSCs may be useful resources for some ophthalmological diseases. The lens is a key refractive element in the eye that focuses images of the visual world onto the retina. To establish a new model for drug screening to treat lens diseases and investigating lens aging and development, we examined whether human lens epithelial cells (HLECs could be induced into iPSCs and if lens-specific differentiation of these cells could be achieved under defined chemical conditions. We first efficiently reprogrammed HLECs from age-related cataract patients to iPSCs with OCT-4, SOX-2, and KLF-4. The resulting HLEC-derived iPS (HLE-iPS colonies were indistinguishable from human ES cells with respect to morphology, gene expression, pluripotent marker expression and their ability to generate all embryonic germ-cell layers. Next, we performed a 3-step induction procedure: HLE-iPS cells were differentiated into large numbers of lens progenitor-like cells with defined factors (Noggin, BMP and FGF2, and we determined that these cells expressed lens-specific markers (PAX6, SOX2, SIX3, CRYAB, CRYAA, BFSP1, and MIP. In addition, HLE-iPS-derived lens cells exhibited reduced expression of epithelial mesenchymal transition (EMT markers compared with human embryonic stem cells (hESCs and fibroblast-derived iPSCs. Our study describes a highly efficient procedure for generating lens progenitor cells from cataract patient HLEC-derived iPSCs. These patient-derived pluripotent cells provide a valuable model for studying the developmental and molecular biological mechanisms that underlie cell determination in lens development and cataract

  7. The Ultrawideband Leaky Lens Antenna

    NARCIS (Netherlands)

    Bruni, S.; Neto, A.; Marliani, F.

    2007-01-01

    A novel directive and nondispersive antenna is presented: the ultrawideband (UWB) leaky lens. It is based on the broad band Cherenkov radiation occurring at a slot printed between different infinite homogeneous dielectrics. The first part of the paper presents the antenna concept and the UWB design.

  8. Development of a novel non-contact inspection technique to detect micro cracks under the surface of a glass substrate by thermal stress-induced light scattering method

    Science.gov (United States)

    Sakata, Yoshitaro; Terasaki, Nao; Nonaka, Kazuhiro

    2017-05-01

    Fine polishing techniques, such as a chemical mechanical polishing treatment, are important techniques in glass substrate manufacturing. However, these techniques may cause micro cracks under the surface of glass substrates because they used mechanical friction. A stress-induced light scattering method (SILSM), which was combined with light scattering method and mechanical stress effects, was proposed for inspecting surfaces to detect polishing-induced micro cracks. However, in the conventional SILSM, samples need to be loaded with physical contact, and the loading point is invisible in transparent materials. Here, we introduced a novel non-contact SILSM using a heating device. A glass substrate was heated first, and then the light scattering intensity of micro cracks was detected by a cooled charge-couple device camera during the natural cooling process. Results clearly showed during the decreasing surface temperature of a glass substrate, appropriate thermal stress is generated for detecting micro cracks by using the SILSM and light scattering intensity from micro cracks changes. We confirmed that non-contact thermal SILSM (T-SILSM) can detect micro cracks under the surface of transparent materials.

  9. Qualification of a Null Lens Using Image-Based Phase Retrieval

    Science.gov (United States)

    Bolcar, Matthew R.; Aronstein, David L.; Hill, Peter C.; Smith, J. Scott; Zielinski, Thomas P.

    2012-01-01

    In measuring the figure error of an aspheric optic using a null lens, the wavefront contribution from the null lens must be independently and accurately characterized in order to isolate the optical performance of the aspheric optic alone. Various techniques can be used to characterize such a null lens, including interferometry, profilometry and image-based methods. Only image-based methods, such as phase retrieval, can measure the null-lens wavefront in situ - in single-pass, and at the same conjugates and in the same alignment state in which the null lens will ultimately be used - with no additional optical components. Due to the intended purpose of a Dull lens (e.g., to null a large aspheric wavefront with a near-equal-but-opposite spherical wavefront), characterizing a null-lens wavefront presents several challenges to image-based phase retrieval: Large wavefront slopes and high-dynamic-range data decrease the capture range of phase-retrieval algorithms, increase the requirements on the fidelity of the forward model of the optical system, and make it difficult to extract diagnostic information (e.g., the system F/#) from the image data. In this paper, we present a study of these effects on phase-retrieval algorithms in the context of a null lens used in component development for the Climate Absolute Radiance and Refractivity Observatory (CLARREO) mission. Approaches for mitigation are also discussed.

  10. Lens stem cells may reside outside the lens capsule: an hypothesis

    Directory of Open Access Journals (Sweden)

    Meyer Rita A

    2007-06-01

    Full Text Available Abstract In this paper, we consider the ocular lens in the context of contemporary developments in biological ideas. We attempt to reconcile lens biology with stem cell concepts and a dearth of lens tumors. Historically, the lens has been viewed as a closed system, in which cells at the periphery of the lens epithelium differentiate into fiber cells. Theoretical considerations led us to question whether the intracapsular lens is indeed self-contained. Since stem cells generate tumors and the lens does not naturally develop tumors, we reasoned that lens stem cells may not be present within the capsule. We hypothesize that lens stem cells reside outside the lens capsule, in the nearby ciliary body. Our ideas challenge the existing lens biology paradigm. We begin our discussion with lens background information, in order to describe our lens stem cell hypothesis in the context of published data. Then we present the ciliary body as a possible source for lens stem cells, and conclude by comparing the ocular lens with the corneal epithelium.

  11. Simulation of an Aspheric Glass Lens Forming Behavior in Progressive GMP Process

    International Nuclear Information System (INIS)

    Chang, Sung Ho; Lee, Young Min; Kang, Jeong Jin; Hong, Seok Kwan; Shin, Gwang Ho; Heo, Young Moo; Jung, Tae Sung

    2007-01-01

    Recently, GMP(Glass Molding Press) process is mainly used to produce aspheric glass lenses. Because glass lens is heated at high temperature above Tg (Transformation Temperature) for forming the glass, the quality of aspheric glass lens is deteriorated by residual stresses which are generated in a aspheric glass lens after forming. In this study, as a fundamental study to develop the mold for progressive GMP process, we conducted a aspheric glass lens forming simulation. Prior to a aspheric glass lens forming simulation, compression and thermal conductivity tests were carried out to obtain mechanical and thermal properties of K-PBK40 which is newly developed material for precision molding, and flow characteristics of K-PBK40 were obtained at high temperature. Then, using the flow characteristics obtained, compression simulation was carried out and compared with the experimental result for the purpose of verifying the obtained flow characteristics. Finally, a glass lens press simulation in progressive GMP process was carried out and we could forecast the shape of deformed glass lenses and residual stresses contribution in the structure of deformed glass lenses after forming

  12. Modern lens antennas for communications engineering

    CERN Document Server

    Thornton, John

    2012-01-01

    The aim of this book is to present the modern design principles and analysis of lens antennas. It gives graduates and RF/Microwave professionals the design insights in order to make full use of lens antennas.  Why do we want to write a book in lens antennas? Because this topic has not been thoroughly publicized, its importance is underestimated. As antennas play a key role in communication systems, recent development in wireless communications would indeed benefit from the characteristics of lens antennas: low profile, and low cost etc.  The major advantages of lens antennas are na

  13. Mechanical and electrical design of the Fermilab lithium lens and transformer system

    International Nuclear Information System (INIS)

    Dugan, G.; Hojvat, C.; Lennox, A.J.; Biallas, G.; Cilyo, F.; Leininger, M.; McCarthy, J.; Sax, W.; Snowdon, S.

    1983-03-01

    A lithium-lens focusing device will be used for the collection of 8-GeV antiprotons in the Fermilab Tevatron I Project. The details of the mechanical and electrical design of the Fermilab lens and its associated toroidal transformer are discussed. The lens, with a radium of 1 cm and length 15 cm, is expected to achieve gradients of 1000 T/m for a focal distance of 0.225 m. The gradient requires a current on the order of 5 x 10 5 A, resulting in large electromagnetic and thermal stresses. The power-supply discharge current and the effect of the inductance of the power leads and connections are minimized by the use of a toroidal matching transformer surrounding the lens itself

  14. Athermal design for mid-wave infrared lens with long EFFL

    Science.gov (United States)

    Bai, Yu; Xing, Tingwen

    2016-10-01

    When the environment temperature has changed, then each parameter in infrared lens has also changed, thus the image quality became bad, so athermal technology is one of key technology in designing infrared lens. The temperature influence of each parameter in infrared lens is analyzed in the paper. In the paper, an athermal mid-wave infrared optical system with long focal length by Code-v optical design software was presented. The parameters of the athermal infrared system are 4.0 f/number, 704mm effective focal length (EFL) , 1° field of view and 3.7-4.8 μm spectrum region 100% cold shield efficiency. When the spatial frequency is 16lp/mm, the Modulation Transfer Function (MTF) of all the field of view was above 0.5 from the working temperature range -40° to 60°. From the image quality and thermal analysis result, we knew that the lens had good athermal performance.

  15. Treatment of a dislocated lens by transcorneal vitrectomy and bimanual phacoemulsification

    Directory of Open Access Journals (Sweden)

    Watanabe A

    2014-08-01

    Full Text Available Akira Watanabe, Tamaki Gekka, Hiroshi Tsuneoka Department of Ophthalmology, The Jikei University School of Medicine, Tokyo, Japan Background: As a method of treatment for a dropped lens nucleus, which occurred during cataract surgery, the dropped lens nucleus was removed through the corneal wound without using pars plana vitrectomy (PPV. After vitrectomy, the dropped lens nucleus was floated on the perfluorocarbon liquid (PFCL. The floating lens nucleus was then phacoemulsified and aspirated. During surgery, irrigation from the anterior chamber was performed. This method was very effective for treatment of a dropped hard nucleus.Case report: During cataract surgery on the left eye of an 80-year-old woman, a posterior capsule rupture occurred. As a result, the lens nucleus dropped into the vitreous cavity. Irrigation to the anterior chamber was performed, with an anterior chamber maintainer inserted through a newly created side port at the corneal limbus. A vitreous cutter and a light guide were inserted in order to perform vitrectomy through the corneal incisions that were created for the cataract surgery. After vitrectomy, the dropped lens nucleus was floated using PFCL. The floating lens nucleus was removed by a bimanual phacoemulsification technique, with the anterior chamber irrigation continuing. The separation of the irrigation port and the aspiration port allowed for effective treatment of the dropped nucleus that was floating on the PFCL, even using a ­phacoemulsification machine with a peristaltic pump system. Safe and effective vitrectomy, similar to a PPV, could be performed with this method using three corneal ports.Conclusion: This technique may allow safer and more effective treatment for a dropped lens nucleus compared with conventional PPV. With this technique, corneal distortion due to surgical manipulation can lead to reduced visibility of the posterior eye. Keywords: dislocated lens, transcorneal vitrectomy, bimanual

  16. Lens decenter and tilt measurement by interferogram

    Science.gov (United States)

    Hung, Min-Wei; Wu, Wen-Hong; Huang, Kuo-Cheng

    2009-11-01

    For the recent years, the vigorous development of the electro-optic industry, particularly the digital camera and the cellular phone camera, has placed a larger and larger demand for the optical devices. Among the optical lens, the aspherical optical lens plays the key component because the aspherical lens may provide better imaging quality then the spherical lens does. For the manufacturing reason, the aspherical lens is prone to a decenter or tilt issue with respect to the optical axes of its two surfaces. To measure decenter and tile error specifically would help to obviate the deficient lens, but most of the present measuring method can't provide this function. This paper proposed a new method to specifically measure the decenter and tile of lens by observing the interferogram of each surface. And the corresponding measuring instrument, which contains interferometer and motion stages, was introduced as well.

  17. Plasma Lens for Muon and Neutrino Beams

    Science.gov (United States)

    Kahn, Stephen; Korenev, Sergey; Bishai, Mary; Diwan, Milind; Gallardo, Juan; Hershcovitch, Ady; Johnson, Brant

    2008-04-01

    The plasma lens is examined as an alternate to focusing horns and solenoids for use in a neutrino or muon beam facility. The plasma lens concept is based on a combined high-current lens/target configuration. The current is fed at electrodes located upstream and downstream from the target where pion capturing is needed. The current flows primarily in the plasma, which has a lower resistivity than the target. A second plasma lens section, with an additional current feed, follows the target to provide shaping of the plasma stability. The geometry of the plasma is shaped to provide optimal pion capture. Simulations of this plasma lens system have shown a 25% higher neutrino production than the horn system. A plasma lens has additional advantage: larger axial current than horns, minimal neutrino contamination during antineutrino running, and negligible pion absorption or scattering. Results from particle simulations using a plasma lens will be presented.

  18. Experimental evaluation of different mixing promoter for nuclear fuel element by means of a new thermal tracing technique

    International Nuclear Information System (INIS)

    Silin, Nicolas; Juanico, Luis; Delmastro, Dario

    2004-01-01

    In this work a new experimental method is used to experimentally evaluate the performance of different appendages promoting the turbulent mixing between the coupled subchannels of nuclear fuel elements.The method used will be introduced in another presentation and consists in the generation and measurement of small thermal traces in the refrigerating water flow between the fuel rods.Because it is suitable for heterogeneous and compact subchannels (as Argentinean fuels) with high water flows in simple and affordable tests at atmospheric pressure, this new method is specially well suited for the design of fuel elements, while it offers advantages over other methods of mixing measurement.The experiments carried out on a small test section proved that the buttons brazed to the fuel rods (similar to the 'turbulence promoters' of the Canflex fuel) had an excellent thermohydraulic performance as compared to different mixing vane designs studied.The thermal traces method developed has shown its potential as a thermohydraulic design tool for the development of advanced nuclear fuels, that eventually incorporate mixing promoter elements. In the case of CARA, and as it includes spacer grids, it could be possible to use them to incorporate these elements without the need of brazing them to the rods (as is the case in Canflex), and therefore without penalizing its integrity [es

  19. Remotely controlled cutting techniques in the field of nuclear decommissioning. Overview of effectively applied thermal cutting methods

    International Nuclear Information System (INIS)

    Bienia, H.; Klotz, B.

    2008-01-01

    This article describes 3 thermal cutting technologies that are effectively used in nuclear decommissioning projects: the autonomous flame cutting, the plasma arc cutting and the contact arc metal cutting. The autonomous flame cutting technology is based on a high pressure oxygen jet oxidizing the material in a small kerf. Not all metal types are appropriate for this technology. The plasma arc cutting, in contrast to the previous technology, uses an electronically induced plasma arc to melt a kerf in the material. Inside the plasma arc temperatures up to 30.000 K exist, so in theory, this temperature is sufficient to cut all materials. Contact arc metal cutting is a new thermal cutting technology for under-water cutting works. Here, a carbon blade cuts the components. An electric arc between the cutting blade and component melts a kerf into the material easing the cutting. This technology allows the cutting of complex structures with hollows. The applications in nuclear facility dismantling of these 3 cutting technologies and their limits are reported and their requirements (staff, investment) listed in a table. (A.C.)

  20. Practical application of the benchmarking technique to increase reliability and efficiency of power installations and main heat-mechanic equipment of thermal power plants

    Science.gov (United States)

    Rimov, A. A.; Chukanova, T. I.; Trofimov, Yu. V.

    2016-12-01

    Data on the comparative analysis variants of the quality of power installations (benchmarking) applied in the power industry is systematized. It is shown that the most efficient variant of implementation of the benchmarking technique is the analysis of statistical distributions of the indicators in the composed homogenous group of the uniform power installations. The benchmarking technique aimed at revealing the available reserves on improvement of the reliability and heat efficiency indicators of the power installations of the thermal power plants is developed in the furtherance of this approach. The technique provides a possibility of reliable comparison of the quality of the power installations in their homogenous group limited by the number and adoption of the adequate decision on improving some or other technical characteristics of this power installation. The technique provides structuring of the list of the comparison indicators and internal factors affecting them represented according to the requirements of the sectoral standards and taking into account the price formation characteristics in the Russian power industry. The mentioned structuring ensures traceability of the reasons of deviation of the internal influencing factors from the specified values. The starting point for further detail analysis of the delay of the certain power installation indicators from the best practice expressed in the specific money equivalent is positioning of this power installation on distribution of the key indicator being a convolution of the comparison indicators. The distribution of the key indicator is simulated by the Monte-Carlo method after receiving the actual distributions of the comparison indicators: specific lost profit due to the short supply of electric energy and short delivery of power, specific cost of losses due to the nonoptimal expenditures for repairs, and specific cost of excess fuel equivalent consumption. The quality loss indicators are developed

  1. Integrated Lens Antennas for Multi-Pixel Receivers

    Science.gov (United States)

    Lee, Choonsup; Chattopadhyay, Goutam

    2011-01-01

    Future astrophysics and planetary experiments are expected to require large focal plane arrays with thousands of detectors. Feedhorns have excellent performance, but their mass, size, fabrication challenges, and expense become prohibitive for very large focal plane arrays. Most planar antenna designs produce broad beam patterns, and therefore require additional elements for efficient coupling to the telescope optics, such as substrate lenses or micromachined horns. An antenna array with integrated silicon microlenses that can be fabricated photolithographically effectively addresses these issues. This approach eliminates manual assembly of arrays of lenses and reduces assembly errors and tolerances. Moreover, an antenna array without metallic horns will reduce mass of any planetary instrument significantly. The design has a monolithic array of lens-coupled, leaky-wave antennas operating in the millimeter- and submillimeter-wave frequencies. Electromagnetic simulations show that the electromagnetic fields in such lens-coupled antennas are mostly confined in approximately 12 15 . This means that one needs to design a small-angle sector lens that is much easier to fabricate using standard lithographic techniques, instead of a full hyper-hemispherical lens. Moreover, this small-angle sector lens can be easily integrated with the antennas in an array for multi-pixel imager and receiver implementation. The leaky antenna is designed using double-slot irises and fed with TE10 waveguide mode. The lens implementation starts with a silicon substrate. Photoresist with appropriate thickness (optimized for the lens size) is spun on the substrate and then reflowed to get the desired lens structure. An antenna array integrated with individual lenses for higher directivity and excellent beam profile will go a long way in realizing multi-pixel arrays and imagers. This technology will enable a new generation of compact, low-mass, and highly efficient antenna arrays for use in multi

  2. Thermal Stability of Oil Palm Empty Fruit Bunch (OPEFB) Nanocrystalline Cellulose: Effects of post-treatment of oven drying and solvent exchange techniques

    International Nuclear Information System (INIS)

    Indarti, E; Wanrosli, W D; Marwan

    2015-01-01

    Nanocrystallinecellulose (NCC) from biomass is a promising material with huge potentials in various applications. A big challenge in its utilization is the agglomeration of the NCC's during processing due to hydrogen bonding among the cellulose chains when in close proximity to each other. Obtaining NCC's in a non-agglomerated and non-aqueous condition is challenging. In the present work NCC's was isolated from oil palm empty fruit bunch (OPEFB) using TEMPO-oxidation reaction method. To obtain non-agglomerated and non-aqueous products, the NCC's underwent post-treatment using oven drying (OD) and solvent exchanged (SE) techniques. The thermal stability of all samples was determined from TGA and DTG profiles whilst FTIR was used to analyzethe chemical modifications that occurred under these conditions. NCC-SE has better thermal stability than the NCC-OD and its on-set degradation temperature and residue are also higher. FTIR analysis shows that NCC-SE has a slightly different chemical composition whereby the absorption band at 1300 cm -1 (due to C-O symmetric stretching) is absent as compared to NCC-OD indicating that in NCC-SE the carboxylate group is in acid form which contribute to its thermal stability (paper)

  3. Correction factor to determine total hydrogen+deuterium concentration obtained by inert gas fusion-thermal conductivity detection (IGF- TCD) technique

    International Nuclear Information System (INIS)

    Ramakumar, K.L.; Sesha Sayi, Y.; Shankaran, P.S.; Chhapru, G.C; Yadav, C.S.; Venugopal, V.

    2004-01-01

    The limitation of commercially available dedicated equipment based on Inert Gas Fusion- Thermal Conductivity Detection (IGF - TCD) for the determination of hydrogen+deuterium is described. For a given molar concentration, deuterium is underestimated vis a vis hydrogen because of lower thermal conductivity and not considering its molecular weight in calculations. An empirical correction factor based on the differences between the thermal conductivities of hydrogen, deuterium and the carrier gas argon, and the mole fraction of deuterium in the sample has been derived to correct the observed hydrogen+deuterium concentration. The corrected results obtained by IGF - TCD technique have been validated by determining hydrogen and deuterium contents in a few samples using an independent method based on hot vacuum extraction-quadrupole mass spectrometry (HVE-QMS). Knowledge of mole fraction of deuterium (XD) is necessary to effect the correction. The correction becomes insignificant at low X D values (XD < 0.2) as the precision in the IGF measurements is comparable with the extent of correction. (author)

  4. Metamaterial-based half Maxwell fish-eye lens for broadband directive emissions

    Science.gov (United States)

    Dhouibi, Abdallah; Nawaz Burokur, Shah; de Lustrac, André; Priou, Alain

    2013-01-01

    The broadband directive emission from a metamaterial surface is numerically and experimentally reported. The metasurface, composed of non-resonant complementary closed ring structures, is designed to obey the refractive index of a half Maxwell fish-eye lens. A planar microstrip Vivaldi antenna is used as transverse magnetic polarized wave launcher for the lens. A prototype of the lens associated with its feed structure has been fabricated using standard lithography techniques. To experimentally demonstrate the broadband focusing properties and directive emissions, both the far-field radiation patterns and the near-field distributions have been measured. Measurements agree quantitatively and qualitatively with theoretical simulations.

  5. Eyeglasses Lens Contour Extraction from Facial Images Using an Efficient Shape Description

    Directory of Open Access Journals (Sweden)

    Diana Borza

    2013-10-01

    Full Text Available This paper presents a system that automatically extracts the position of the eyeglasses and the accurate shape and size of the frame lenses in facial images. The novelty brought by this paper consists in three key contributions. The first one is an original model for representing the shape of the eyeglasses lens, using Fourier descriptors. The second one is a method for generating the search space starting from a finite, relatively small number of representative lens shapes based on Fourier morphing. Finally, we propose an accurate lens contour extraction algorithm using a multi-stage Monte Carlo sampling technique. Multiple experiments demonstrate the effectiveness of our approach.

  6. Development of a Laue lens for nuclear astrophysics

    International Nuclear Information System (INIS)

    Rousselle, Julien

    2011-01-01

    prototype, it have been possible to maintain the required precision through the various steps of alignment, mounting and space qualification testing i.e. characterizing the crystal plane orientation, machining the lens support, cementing the crystals on the support, vibration tests, and thermal cycling

  7. Thermal conversion of municipal solid waste via hydrothermal carbonization: comparison of carbonization products to products from current waste management techniques.

    Science.gov (United States)

    Lu, Xiaowei; Jordan, Beth; Berge, Nicole D

    2012-07-01

    Hydrothermal carbonization (HTC) is a novel thermal conversion process that may be a viable means for managing solid waste streams while minimizing greenhouse gas production and producing residual material with intrinsic value. HTC is a wet, relatively low temperature (180-350 °C) thermal conversion process that has been shown to convert biomass to a carbonaceous residue referred to as hydrochar. Results from batch experiments indicate HTC of representative waste materials is feasible, and results in the majority of carbon (45-75% of the initially present carbon) remaining within the hydrochar. Gas production during the batch experiments suggests that longer reaction periods may be desirable to maximize the production of energy-favorable products. If using the hydrochar for applications in which the carbon will remain stored, results suggest that the gaseous products from HTC result in fewer g CO(2)-equivalent emissions than the gases associated with landfilling, composting, and incineration. When considering the use of hydrochar as a solid fuel, more energy can be derived from the hydrochar than from the gases resulting from waste degradation during landfilling and anaerobic digestion, and from incineration of food waste. Carbon emissions resulting from the use of the hydrochar as a fuel source are smaller than those associated with incineration, suggesting HTC may serve as an environmentally beneficial alternative to incineration. The type and extent of environmental benefits derived from HTC will be dependent on hydrochar use/the purpose for HTC (e.g., energy generation or carbon storage). Copyright © 2012 Elsevier Ltd. All rights reserved.

  8. Scleral fixation of a single-piece multifocal intraocular lens.

    Science.gov (United States)

    Can, Ertugrul; Basaran, M Resat; Gül, Adem

    2013-01-01

    We describe an ab interno technique for injector implantation of a one-piece multifocal intraocular lens (IOL). Transscleral fixation of multifocal posterior chamber IOL implantation using an injector with ab interno technique was performed in an eye of a 9-year-old girl who had undergone pars plana lensectomy 2 years before for bilateral lens subluxation with unknown etiology. No major complications were encountered during a 3-month follow-up of the patient and excellent centration was observed during the follow-up period. Her preoperative best spectacle-corrected distance visual acuity of 20/32 improved to uncorrected distance visual acuity of 20/25. Closed-loop design of IOL served the function of eyelets and position of the IOL was provided using only a 2-point fixation. Intraoperative position adjustment of the IOL provided an excellent centralization of multifocal IOL.

  9. Lens Coupled Quantum Cascade Laser

    Science.gov (United States)

    Hu, Qing (Inventor); Lee, Alan Wei Min (Inventor)

    2013-01-01

    Terahertz quantum cascade (QC) devices are disclosed that can operate, e.g., in a range of about 1 THz to about 10 THz. In some embodiments, QC lasers are disclosed in which an optical element (e.g., a lens) is coupled to an output facet of the laser's active region to enhance coupling of the lasing radiation from the active region to an external environment. In other embodiments, terahertz amplifier and tunable terahertz QC lasers are disclosed.

  10. Looking beyond the perfect lens

    International Nuclear Information System (INIS)

    Wee, W H; Pendry, J B

    2010-01-01

    The holy grail of imaging is the ability to see through anything. From the conservation of energy, we can easily see that to see through a lossy material would require lenses with gain. The aim of this paper therefore is to propose a simple scheme by which we can construct a general perfect lens, with gain-one that can restore both the phases and amplitudes of near and far fields.

  11. CONTACT LENS RELATED CORNEAL ULCER

    Directory of Open Access Journals (Sweden)

    AGARWAL P

    2010-01-01

    Full Text Available A corneal ulcer caused by infection is one of the major causes of blindness worldwide. One of the recent health concerns is the increasing incidence of corneal ulcers associated with contact lens user especially if the users fail to follow specific instruction in using their contact lenses. Risk factors associated with increased risk of contact lens related corneal ulcers are:overnight wear, long duration of continuous wear, lower socio-economic classes, smoking, dry eye and poor hygiene. The presenting symptoms of contact lens related corneal ulcers include eye discomfort, foreign body sensation and lacrimation. More serious symptoms are redness (especially circum-corneal injection, severe pain, photophobia, eye discharge and blurring of vision. The diagnosis is established by a thorough slit lamp microscopic examination with fluorescein staining and corneal scraping for Gram stain and culture of the infective organism. Delay in diagnosing and treatment can cause permanent blindness, therefore an early referral to ophthalmologist and commencing of antimicrobial therapy can prevent visual loss.

  12. Glycation precedes lens crystallin aggregation

    International Nuclear Information System (INIS)

    Swamy, M.S.; Perry, R.E.; Abraham, E.C.

    1987-01-01

    Non-enzymatic glycosylation (glycation) seems to have the potential to alter the structure of crystallins and make them susceptible to thiol oxidation leading to disulfide-linked high molecular weight (HMW) aggregate formation. They used streptozotocin diabetic rats during precataract and cataract stages and long-term cell-free glycation of bovine lens crystallins to study the relationship between glycation and lens crystallin aggregation. HMW aggregates and other protein components of the water-soluble (WS) and urea-soluble (US) fractions were separated by molecular sieve high performance liquid chromatography. Glycation was estimated by both [ 3 H]NaBH 4 reduction and phenylboronate agarose affinity chromatography. Levels of total glycated protein (GP) in the US fractions were about 2-fold higher than in the WS fractions and there was a linear increase in GP in both WS and US fractions. This increase was parallelled by a corresponding increase in HMW aggregates. Total GP extracted by the affinity method from the US fraction showed a predominance of HMW aggregates and vice versa. Cell-free glycation studies with bovine crystallins confirmed the results of the animals studies. Increasing glycation caused a corresponding increase in protein insolubilization and the insoluble fraction thus formed also contained more glycated protein. It appears that lens protein glycation, HMW aggregate formation, and protein insolubilization are interrelated

  13. Spontaneous resorption of sub-retinal cortical lens material

    Directory of Open Access Journals (Sweden)

    Salil S Gadkari

    2014-01-01

    Full Text Available We report a rare case of retained sub-retinal cortical material, which underwent spontaneous resorption. Patient presented with a left eye traumatic retinal detachment with a large retinal tear and posteriorly dislocated cataractous lens. Vitrectomy, lensectomy, silicone oil injection, and endolaser were performed. A good visual result was achieved. The report draws attention to this condition and highlights possible technique for minimizing risk of this complication in similar cases.

  14. Ultrafast Degenerate Transient Lens Spectroscopy in Semiconductor Nanosctructures

    Directory of Open Access Journals (Sweden)

    Leontyev A.V.

    2015-01-01

    Full Text Available We report the non-resonant excitation and probing of the nonlinear refractive index change in bulk semiconductors and semiconductor quantum dots through degenerate transient lens spectroscopy. The signal oscillates at the center laser field frequency, and the envelope of the former in quantum dots is distinctly different from the one in bulk sample. We discuss the applicability of this technique for polarization state probing in semiconductor media with femtosecond temporal resolution.

  15. Protection of Reinforced Concrete Structures of Waste Water Treatment Reservoirs with Stainless Steel Coating Using Arc Thermal Spraying Technique in Acidified Water

    Directory of Open Access Journals (Sweden)

    Han-Seung Lee

    2016-09-01

    Full Text Available Waste water treatment reservoirs are contaminated with many hazardous chemicals and acids. Reservoirs typically comprise concrete and reinforcement steel bars, and the main elements responsible for their deterioration are hazardous chemicals, acids, and ozone. Currently, a variety of techniques are being used to protect reservoirs from exposure to these elements. The most widely used techniques are stainless steel plating and polymeric coating. In this study, a technique known as arc thermal spraying was used. It is a more convenient and economical method for protecting both concrete and reinforcement steel bar from deterioration in waste water treatment reservoirs. In this study, 316L stainless steel coating was applied to a concrete surface, and different electrochemical experiments were performed to evaluate the performance of coatings in different acidic pH solutions. The coating generated from the arc thermal spraying process significantly protected the concrete surface from corrosion in acidic pH solutions, owing to the formation of a double layer capacitance—a mixture of Cr3+ enriched with Cr2O3 and Cr-hydroxide in inner and Fe3+ oxide on the outer layer of the coating. The formation of this passive film is defective owing to the non-homogeneous 316L stainless steel coating surface. In the pH 5 solution, the growth of a passive film is adequate due to the presence of un-dissociated water molecules in the aqueous sulfuric acid solution. The coated surface is sealed with alkyl epoxide, which acts as a barrier against the penetration of acidic solutions. This coating exhibits higher impedance values among the three studied acidic pH solutions.

  16. The Effect of the Crystalline Lens on Central Vault After Implantable Collamer Lens Implantation.

    Science.gov (United States)

    Qi, Meng-Ying; Chen, Qian; Zeng, Qing-Yan

    2017-08-01

    To identify associations between crystalline lens-related factors and central vault after Implantable Collamer Lens (ICL) (Staar Surgical, Monrovia, CA) implantation. This retrospective clinical study included 320 eyes from 186 patients who underwent ICL implantation surgery. At 1 year after surgery, the central vault was measured using anterior segment optical coherence tomography. Preoperative anterior chamber depth, lens thickness, lens position (lens position = anterior chamber depth + 1/2 lens thickness), and vault were analyzed to investigate the effects of lens-related factors on postoperative vault. The mean vault was 513 ± 215 µm at 1 year after surgery. Vault was positively correlated with preoperative anterior chamber depth (r = 0.495, P lens position (r = 0.371, P lens thickness (r = -0.262, P lens position than eyes in the other two vault groups (which had vaults ≥ 250 µm) (P lens position less than 5.1 mm had greatly reduced vaults (P lens could have an important influence on postoperative vault. Eyes with a shallower anterior chamber and a forward lens position will have lower vaults. [J Refract Surg. 2017;33(8):519-523.]. Copyright 2017, SLACK Incorporated.

  17. Non-invasive thermal profiling of silicon wafer surface during RTP using acoustic and signal processing techniques

    Science.gov (United States)

    Syed, Ahmed Rashid

    Among the great physical challenges faced by the current front-end semiconductor equipment manufacturers is the accurate and repeatable surface temperature measurement of wafers during various fabrication steps. Close monitoring of temperature is essential in that it ensures desirable device characteristics to be reliably reproduced across various wafer lots. No where is the need to control temperature more pronounced than it is during Rapid Thermal Processing (RTP) which involves temperature ramp rates in excess of 200°C/s. This dissertation presents an elegant and practical approach to solve the wafer surface temperature estimation problem, in context of RTP, by deploying hardware that acquires the necessary data while preserving the integrity and purity of the wafer. In contrast to the widely used wafer-contacting (and hence contaminating) methods, such as bonded thermocouples, or environment sensitive schemes, such as light-pipes and infrared pyrometry, the proposed research explores the concept of utilizing Lamb (acoustic) waves to detect changes in wafer surface temperature, during RTP. Acoustic waves are transmitted to the wafer via an array of quartz rods that normally props the wafer inside an RTP chamber. These waves are generated using piezoelectric transducers affixed to the bases of the quartz rods. The group velocity of Lamb waves traversing the wafer surface undergoes a monotonic decrease with rise in wafer temperature. The correspondence of delay in phase of the received Lamb waves and the ambient temperature, along all direct paths between sending and receiving transducers, yields a psuedo real-time thermal image of the wafer. Although the custom built hardware-setup implements the above "proof-of-concept" scheme by transceiving acoustic signals at a single frequency, the real-world application will seek to enhance the data acquistion. rate (>1000 temperature measurements per seconds) by sending and receiving Lamb waves at multiple frequencies (by

  18. Development of an optimization technique of CETOP-D inlet flow factor for reactor core thermal margin improvement

    International Nuclear Information System (INIS)

    Hong, Sung Duk; Im, Jong Sun; Yoo, Yun Jong; Kwon, Jung Taek; Park, Jong Ryool

    1995-01-01

    The recent ABB/CE(Asea Brown Boveri Combustion Engineering) type pressurized water reactors have the on-line monitoring system, i.e., the COLSS(core operating limit supervisory system), to prevent the specified acceptable fuel design limits from being violated during normal operation and anticipated operational occurrences. One of the main functions of COLSS is the on-line monitoring of the DNB(departure from nucleate boiling) overpower margin by calculating the MDNBR(minimum DNB ratio) for the measured operating condition at every second. The CETOP-D model, used in the MDNBR calculation of COLSS, is benchmarked conservatively against the TORC model using an inlet flow factor of hot assembly in CETOP-D as an adjustment factor for TORC. In this study, a technique to optimize the CETOP-D inlet flow factor has been developed by eliminating the excessive conservatism in the ABB/CE's. A correlation is introduced to account for the actual variation of the CETOP-D inlet flow factor within the core operating limits. This technique was applied to the core operating range of the Yonggwang Units 3 and 4 Cycle 1, which results in the increase of 2% in the DNB overpower margin at the normal operating condition, compared with that from the ABB/CE method. 7 figs., 2 tabs., 10 refs. (Author)

  19. Improving the lens design and performance of a contemporary electromagnetic shock wave lithotripter

    Science.gov (United States)

    Neisius, Andreas; Smith, Nathan B.; Sankin, Georgy; Kuntz, Nicholas John; Madden, John Francis; Fovargue, Daniel E.; Mitran, Sorin; Lipkin, Michael Eric; Simmons, Walter Neal; Preminger, Glenn M.; Zhong, Pei

    2014-01-01

    The efficiency of shock wave lithotripsy (SWL), a noninvasive first-line therapy for millions of nephrolithiasis patients, has not improved substantially in the past two decades, especially in regard to stone clearance. Here, we report a new acoustic lens design for a contemporary electromagnetic (EM) shock wave lithotripter, based on recently acquired knowledge of the key lithotripter field characteristics that correlate with efficient and safe SWL. The new lens design addresses concomitantly three fundamental drawbacks in EM lithotripters, namely, narrow focal width, nonidealized pulse profile, and significant misalignment in acoustic focus and cavitation activities with the target stone at high output settings. Key design features and performance of the new lens were evaluated using model calculations and experimental measurements against the original lens under comparable acoustic pulse energy (E+) of 40 mJ. The −6-dB focal width of the new lens was enhanced from 7.4 to 11 mm at this energy level, and peak pressure (41 MPa) and maximum cavitation activity were both realigned to be within 5 mm of the lithotripter focus. Stone comminution produced by the new lens was either statistically improved or similar to that of the original lens under various in vitro test conditions and was significantly improved in vivo in a swine model (89% vs. 54%, P = 0.01), and tissue injury was minimal using a clinical treatment protocol. The general principle and associated techniques described in this work can be applied to design improvement of all EM lithotripters. PMID:24639497

  20. Modulation of surface structure and catalytic properties of cerium oxide nanoparticles by thermal and microwave synthesis techniques

    Energy Technology Data Exchange (ETDEWEB)

    He, Jian [College of Pharmacy, Third Military Medical University, Chongqing 400038 (China); Zhou, Lan; Liu, Jie; Yang, Lu; Zou, Ling; Xiang, Junyu; Dong, Shiwu [School of Biomedical Engineering, Third Military Medical University, Chongqing 400038 (China); Yang, Xiaochao, E-mail: xcyang@tmmu.edu.cn [School of Biomedical Engineering, Third Military Medical University, Chongqing 400038 (China)

    2017-04-30

    Highlights: • The CNPs synthesized by microwave irradiation have more reactive hot spots than that synthesized by convective heating. • The CNPs synthesized by microwave irradiation exhibited higher SOD activity than that synthesized by convective heating. • The CNPs synthesized by microwave irradiation heating could better protect cells from oxidative stress. - Abstract: Cerium oxide nanoparticles (CNPs) have been intensively explored for biomedical applications in recent few years due to the versatile enzyme mimetic activities of the nanoparticles. However, the control of CNPs quality through the optimization of synthesis conditions remains largely unexplored as most of the previous studies only focus on utilizing the catalytic activities of the nanoparticles. In the present study, CNPs with size about 5 nm were synthesized by thermal decomposition method using traditional convective heating and recently developed microwave irradiation as heating source. The quality of CNPs synthesized by the two heating manner was evaluated. The CNPs synthesized by convective heating were slightly smaller than that synthesized by microwave irradiation heating. The cores of the CNPs synthesized by the two heating manner have similar crystal structure. While the surface subtle structures of the CNPs synthesized by two heating manner were different. The CNPs synthesized by microwave irradiation have more surface reactive hot spot than that synthesized by convective heating as the nanoparticles responded more actively to the redox environment variation. This difference resulted in the higher superoxide dismutase (SOD) mimetic activity of CNPs synthesized by microwave irradiation heating than that of the convective heating. Preliminary experiments indicated that the CNPs synthesized by microwave irradiation heating could better protect cells from oxidative stress due to the higher SOD mimetic activity of the nanoparticles.

  1. Modulation of surface structure and catalytic properties of cerium oxide nanoparticles by thermal and microwave synthesis techniques

    International Nuclear Information System (INIS)

    He, Jian; Zhou, Lan; Liu, Jie; Yang, Lu; Zou, Ling; Xiang, Junyu; Dong, Shiwu; Yang, Xiaochao

    2017-01-01

    Highlights: • The CNPs synthesized by microwave irradiation have more reactive hot spots than that synthesized by convective heating. • The CNPs synthesized by microwave irradiation exhibited higher SOD activity than that synthesized by convective heating. • The CNPs synthesized by microwave irradiation heating could better protect cells from oxidative stress. - Abstract: Cerium oxide nanoparticles (CNPs) have been intensively explored for biomedical applications in recent few years due to the versatile enzyme mimetic activities of the nanoparticles. However, the control of CNPs quality through the optimization of synthesis conditions remains largely unexplored as most of the previous studies only focus on utilizing the catalytic activities of the nanoparticles. In the present study, CNPs with size about 5 nm were synthesized by thermal decomposition method using traditional convective heating and recently developed microwave irradiation as heating source. The quality of CNPs synthesized by the two heating manner was evaluated. The CNPs synthesized by convective heating were slightly smaller than that synthesized by microwave irradiation heating. The cores of the CNPs synthesized by the two heating manner have similar crystal structure. While the surface subtle structures of the CNPs synthesized by two heating manner were different. The CNPs synthesized by microwave irradiation have more surface reactive hot spot than that synthesized by convective heating as the nanoparticles responded more actively to the redox environment variation. This difference resulted in the higher superoxide dismutase (SOD) mimetic activity of CNPs synthesized by microwave irradiation heating than that of the convective heating. Preliminary experiments indicated that the CNPs synthesized by microwave irradiation heating could better protect cells from oxidative stress due to the higher SOD mimetic activity of the nanoparticles.

  2. A technique for rapid source apportionment applied to ambient organic aerosol measurements from a thermal desorption aerosol gas chromatograph (TAG

    Directory of Open Access Journals (Sweden)

    Y. Zhang

    2016-11-01

    Full Text Available We present a rapid method for apportioning the sources of atmospheric organic aerosol composition measured by gas chromatography–mass spectrometry methods. Here, we specifically apply this new analysis method to data acquired on a thermal desorption aerosol gas chromatograph (TAG system. Gas chromatograms are divided by retention time into evenly spaced bins, within which the mass spectra are summed. A previous chromatogram binning method was introduced for the purpose of chromatogram structure deconvolution (e.g., major compound classes (Zhang et al., 2014. Here we extend the method development for the specific purpose of determining aerosol samples' sources. Chromatogram bins are arranged into an input data matrix for positive matrix factorization (PMF, where the sample number is the row dimension and the mass-spectra-resolved eluting time intervals (bins are the column dimension. Then two-dimensional PMF can effectively do three-dimensional factorization on the three-dimensional TAG mass spectra data. The retention time shift of the chromatogram is corrected by applying the median values of the different peaks' shifts. Bin width affects chemical resolution but does not affect PMF retrieval of the sources' time variations for low-factor solutions. A bin width smaller than the maximum retention shift among all samples requires retention time shift correction. A six-factor PMF comparison among aerosol mass spectrometry (AMS, TAG binning, and conventional TAG compound integration methods shows that the TAG binning method performs similarly to the integration method. However, the new binning method incorporates the entirety of the data set and requires significantly less pre-processing of the data than conventional single compound identification and integration. In addition, while a fraction of the most oxygenated aerosol does not elute through an underivatized TAG analysis, the TAG binning method does have the ability to achieve molecular level

  3. Robust satellite techniques (RST for the thermal monitoring of earthquake prone areas: the case of Umbria-Marche October, 1997 seismic events

    Directory of Open Access Journals (Sweden)

    V. Tramutoli

    2008-06-01

    Full Text Available Several authors claim a space-time correlation between increases in Earth’s emitted Thermal Infra-Red (TIR radiation and earthquake occurrence. The main problems of such studies regard data analysis and interpretation, which are often done without a validation/confutation control. In this context, a robust data analysis technique (RST, i.e. Robust Satellite Techniques is proposed which permits a statistically based definition of TIR «anomaly » and uses a validation/confutation approach. This technique was already applied to satellite TIR surveys in seismic regions for about twenty earthquakes that occurred in the world. In this work RST is applied for the first time to a time sequence of seismic events. Nine years of Meteosat TIR observations have been analyzed to characterize the unperturbed TIR signal behaviour at specific observation times and locations. The main seismic events of the October 1997 Umbria-Marche sequence have been considered for validation, and relatively unperturbed periods (no earthquakes with Mb ? 4 were taken for confutation purposes. Positive time-space persistent TIR anomalies were observed during seismic periods, generally overlapping the principal tectonic lineaments of the region and sometimes focusing on the vicinity of the epicentre. No similar (in terms of relative intensity and space-time persistence TIR anomalies were detected during seismically unperturbed periods.

  4. TU-E-201-02: Eye Lens Dosimetry From CT Perfusion Studies

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, D. [Toshiba America Medical Systems (United States)

    2015-06-15

    awareness can lead to avoidance or even prevention. Learning Objectives: To understand recent changes in eye lens dose limits and thresholds for tissue reactions To understand different approaches to dose estimation for eye lens To learn about challenges in eye lens opacities among staff in interventional fluoroscopy Di Zhang, Toshiba America Medical Systems, Tustin, CA, USA Eye lens radiation dose from brain perfusion CT exams CT perfusion imaging requires repeatedly exposing one location of the head to monitor the uptake and washout of iodinated contrast. The accumulated radiation dose to the eye lens can be high, leading to concerns about potential radiation injury from these scans. CTDIvol assumes continuous z coverage and can overestimate eye lens dose in CT perfusion scans where the table do not increment. The radiation dose to the eye lens from clinical CT brain perfusion studies can be estimated using Monte Carlo simulation methods on voxelized patient models. MDCT scanners from four major manufacturers were simulated and the eye lens doses were estimated using the AAPM posted clinical protocols. They were also compared to CTDIvol values to evaluate the overestimation from CTDIvol. The efficacy of eye lens dose reduction techniques such as tilting the gantry and moving the scan location away from the eyelens were also investigated. Eye lens dose ranged from 81 mGy to 279 mGy, depending on the scanner and protocol used. It is between 59% and 63% of the CTDIvol values reported by the scanners. The eye lens dose is significantly reduced when the eye lenses were not directly irradiated. CTDIvol should not be interpreted as patient dose; this study has shown it to overestimate dose to the eye lens. These results may be used to provide more accurate estimates of actual dose to ensure that protocols are operated safely below thresholds. Tilting the gantry or moving the scanning region further away from the eyes are effective for reducing lens dose in clinical practice

  5. TU-E-201-00: Eye Lens Dosimetry for Patients and Staff

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2015-06-15

    awareness can lead to avoidance or even prevention. Learning Objectives: To understand recent changes in eye lens dose limits and thresholds for tissue reactions To understand different approaches to dose estimation for eye lens To learn about challenges in eye lens opacities among staff in interventional fluoroscopy Di Zhang, Toshiba America Medical Systems, Tustin, CA, USA Eye lens radiation dose from brain perfusion CT exams CT perfusion imaging requires repeatedly exposing one location of the head to monitor the uptake and washout of iodinated contrast. The accumulated radiation dose to the eye lens can be high, leading to concerns about potential radiation injury from these scans. CTDIvol assumes continuous z coverage and can overestimate eye lens dose in CT perfusion scans where the table do not increment. The radiation dose to the eye lens from clinical CT brain perfusion studies can be estimated using Monte Carlo simulation methods on voxelized patient models. MDCT scanners from four major manufacturers were simulated and the eye lens doses were estimated using the AAPM posted clinical protocols. They were also compared to CTDIvol values to evaluate the overestimation from CTDIvol. The efficacy of eye lens dose reduction techniques such as tilting the gantry and moving the scan location away from the eyelens were also investigated. Eye lens dose ranged from 81 mGy to 279 mGy, depending on the scanner and protocol used. It is between 59% and 63% of the CTDIvol values reported by the scanners. The eye lens dose is significantly reduced when the eye lenses were not directly irradiated. CTDIvol should not be interpreted as patient dose; this study has shown it to overestimate dose to the eye lens. These results may be used to provide more accurate estimates of actual dose to ensure that protocols are operated safely below thresholds. Tilting the gantry or moving the scanning region further away from the eyes are effective for reducing lens dose in clinical practice

  6. TU-E-201-02: Eye Lens Dosimetry From CT Perfusion Studies

    International Nuclear Information System (INIS)

    Zhang, D.

    2015-01-01

    awareness can lead to avoidance or even prevention. Learning Objectives: To understand recent changes in eye lens dose limits and thresholds for tissue reactions To understand different approaches to dose estimation for eye lens To learn about challenges in eye lens opacities among staff in interventional fluoroscopy Di Zhang, Toshiba America Medical Systems, Tustin, CA, USA Eye lens radiation dose from brain perfusion CT exams CT perfusion imaging requires repeatedly exposing one location of the head to monitor the uptake and washout of iodinated contrast. The accumulated radiation dose to the eye lens can be high, leading to concerns about potential radiation injury from these scans. CTDIvol assumes continuous z coverage and can overestimate eye lens dose in CT perfusion scans where the table do not increment. The radiation dose to the eye lens from clinical CT brain perfusion studies can be estimated using Monte Carlo simulation methods on voxelized patient models. MDCT scanners from four major manufacturers were simulated and the eye lens doses were estimated using the AAPM posted clinical protocols. They were also compared to CTDIvol values to evaluate the overestimation from CTDIvol. The efficacy of eye lens dose reduction techniques such as tilting the gantry and moving the scan location away from the eyelens were also investigated. Eye lens dose ranged from 81 mGy to 279 mGy, depending on the scanner and protocol used. It is between 59% and 63% of the CTDIvol values reported by the scanners. The eye lens dose is significantly reduced when the eye lenses were not directly irradiated. CTDIvol should not be interpreted as patient dose; this study has shown it to overestimate dose to the eye lens. These results may be used to provide more accurate estimates of actual dose to ensure that protocols are operated safely below thresholds. Tilting the gantry or moving the scanning region further away from the eyes are effective for reducing lens dose in clinical practice

  7. TU-E-201-00: Eye Lens Dosimetry for Patients and Staff

    International Nuclear Information System (INIS)

    2015-01-01

    awareness can lead to avoidance or even prevention. Learning Objectives: To understand recent changes in eye lens dose limits and thresholds for tissue reactions To understand different approaches to dose estimation for eye lens To learn about challenges in eye lens opacities among staff in interventional fluoroscopy Di Zhang, Toshiba America Medical Systems, Tustin, CA, USA Eye lens radiation dose from brain perfusion CT exams CT perfusion imaging requires repeatedly exposing one location of the head to monitor the uptake and washout of iodinated contrast. The accumulated radiation dose to the eye lens can be high, leading to concerns about potential radiation injury from these scans. CTDIvol assumes continuous z coverage and can overestimate eye lens dose in CT perfusion scans where the table do not increment. The radiation dose to the eye lens from clinical CT brain perfusion studies can be estimated using Monte Carlo simulation methods on voxelized patient models. MDCT scanners from four major manufacturers were simulated and the eye lens doses were estimated using the AAPM posted clinical protocols. They were also compared to CTDIvol values to evaluate the overestimation from CTDIvol. The efficacy of eye lens dose reduction techniques such as tilting the gantry and moving the scan location away from the eyelens were also investigated. Eye lens dose ranged from 81 mGy to 279 mGy, depending on the scanner and protocol used. It is between 59% and 63% of the CTDIvol values reported by the scanners. The eye lens dose is significantly reduced when the eye lenses were not directly irradiated. CTDIvol should not be interpreted as patient dose; this study has shown it to overestimate dose to the eye lens. These results may be used to provide more accurate estimates of actual dose to ensure that protocols are operated safely below thresholds. Tilting the gantry or moving the scanning region further away from the eyes are effective for reducing lens dose in clinical practice

  8. Hand hygiene prior to contact lens handling is problematical.

    Science.gov (United States)

    McMonnies, Charles W

    2012-04-01

    To establish guidelines for contact lens wearers' hand hygiene practices which achieve a balance between minimising risk of infection and reasonable expectations on the ability of patients to follow them. Evidence has been obtained from publications via PubMed, Advanced Medline Search, Cochrane Reviews, Google Scholar and using the key words hand hygiene, washing and contact lens. Guidelines for effective hand washing and the bother involved vary according to the level of hygiene required. High levels of non-compliance with hand hygiene practices, even among healthcare workers, gives an indication of how important the level of bother involved when following guidelines can be in contributing to non-compliance. Better patient education to improve hand washing techniques as well as patient attitudes toward hand hygiene are needed to reduce high non-compliance levels. Better hand hygiene techniques and higher frequency of their application give the prospect of reduced risk of infection and of any discomfort that arises from increased lens and ocular bioburden. In order that adoption rates might be maximised, the guidelines which have been distilled from this review attempt to strike a balance between technique redundancy and the associated higher levels of hygiene achieved and the possibility that the perception of too much bother involved could reduce participation rates. The guidelines have been expanded by the inclusion of suggested explanatory information in the expectation that helping patients to understand why the recommendations are made will have the effect of increasing their adoption. Copyright © 2011 British Contact Lens Association. Published by Elsevier Ltd. All rights reserved.

  9. Role of Aquaporin 0 in lens biomechanics

    International Nuclear Information System (INIS)

    Sindhu Kumari, S.; Gupta, Neha; Shiels, Alan; FitzGerald, Paul G.; Menon, Anil G.; Mathias, Richard T.; Varadaraj, Kulandaiappan

    2015-01-01

    Maintenance of proper biomechanics of the eye lens is important for its structural integrity and for the process of accommodation to focus near and far objects. Several studies have shown that specialized cytoskeletal systems such as the beaded filament (BF) and spectrin-actin networks contribute to mammalian lens biomechanics; mutations or deletion in these proteins alters lens biomechanics. Aquaporin 0 (AQP0), which constitutes ∼45% of the total membrane proteins of lens fiber cells, has been shown to function as a water channel and a structural cell-to-cell adhesion (CTCA) protein. Our recent ex vivo study on AQP0 knockout (AQP0 KO) mouse lenses showed the CTCA function of AQP0 could be crucial for establishing the refractive index gradient. However, biomechanical studies on the role of AQP0 are lacking. The present investigation used wild type (WT), AQP5 KO (AQP5 −/− ), AQP0 KO (heterozygous KO: AQP0 +/− ; homozygous KO: AQP0 −/− ; all in C57BL/6J) and WT-FVB/N mouse lenses to learn more about the role of fiber cell AQPs in lens biomechanics. Electron microscopic images exhibited decreases in lens fiber cell compaction and increases in extracellular space due to deletion of even one allele of AQP0. Biomechanical assay revealed that loss of one or both alleles of AQP0 caused a significant reduction in the compressive load-bearing capacity of the lenses compared to WT lenses. Conversely, loss of AQP5 did not alter the lens load-bearing ability. Compressive load-bearing at the suture area of AQP0 +/− lenses showed easy separation while WT lens suture remained intact. These data from KO mouse lenses in conjunction with previous studies on lens-specific BF proteins (CP49 and filensin) suggest that AQP0 and BF proteins could act co-operatively in establishing normal lens biomechanics. We hypothesize that AQP0, with its prolific expression at the fiber cell membrane, could provide anchorage for cytoskeletal structures like BFs and together they help to

  10. Algorithm design of liquid lens inspection system

    Science.gov (United States)

    Hsieh, Lu-Lin; Wang, Chun-Chieh

    2008-08-01

    In mobile lens domain, the glass lens is often to be applied in high-resolution requirement situation; but the glass zoom lens needs to be collocated with movable machinery and voice-coil motor, which usually arises some space limits in minimum design. In high level molding component technology development, the appearance of liquid lens has become the focus of mobile phone and digital camera companies. The liquid lens sets with solid optical lens and driving circuit has replaced the original components. As a result, the volume requirement is decreased to merely 50% of the original design. Besides, with the high focus adjusting speed, low energy requirement, high durability, and low-cost manufacturing process, the liquid lens shows advantages in the competitive market. In the past, authors only need to inspect the scrape defect made by external force for the glass lens. As to the liquid lens, authors need to inspect the state of four different structural layers due to the different design and structure. In this paper, authors apply machine vision and digital image processing technology to administer inspections in the particular layer according to the needs of users. According to our experiment results, the algorithm proposed can automatically delete non-focus background, extract the region of interest, find out and analyze the defects efficiently in the particular layer. In the future, authors will combine the algorithm of the system with automatic-focus technology to implement the inside inspection based on the product inspective demands.

  11. Freeform lens design for LED collimating illumination.

    Science.gov (United States)

    Chen, Jin-Jia; Wang, Te-Yuan; Huang, Kuang-Lung; Liu, Te-Shu; Tsai, Ming-Da; Lin, Chin-Tang

    2012-05-07

    We present a simple freeform lens design method for an application to LED collimating illumination. The method is derived from a basic geometric-optics analysis and construction approach. By using this method, a highly collimating lens with LED chip size of 1.0 mm × 1.0 mm and optical simulation efficiency of 86.5% under a view angle of ± 5 deg is constructed. To verify the practical performance of the lens, a prototype of the collimator lens is also made, and an optical efficiency of 90.3% with a beam angle of 4.75 deg is measured.

  12. Investigation on development of advanced materials by solvothermal technique; Sorubo thermal hanno riyo senshin zairyo kaihatsu ni kansuru chosa

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1996-03-01

    Solvothermal reaction is reaction under high temperature and high pressure, which is expected to fabricate new functional materials. In this study, the materials are classified into two fields, i.e., inorganic materials, metals and their composites and organic materials and their composites. The current status of R and D of production and processing technology in each field is surveyed and the prospect of it is discussed. For the inorganic materials, metals and their composites, it is explained that very fine metal oxide particles, complex oxides, single crystals, whiskers, compounds with layer structure, metastable compounds, ion conductors and catalysts with high ability could be produced only by controlling the solvothermal reactions in atomic order. For the organic materials and their composites, surveyed results of the solvothermal technique using non-aqueous solutions are mainly provided. The necessity of a national project for researches on the solvothermal reactions is proposed from the viewpoint of resource, environment and energy. 777 refs., 38 figs., 26 tabs.

  13. Solidification in direct metal deposition by LENS processing

    Science.gov (United States)

    Hofmeister, William; Griffith, Michelle

    2001-09-01

    Thermal imaging and metallographic analysis were used to study Laser Engineered Net Shaping (LENS™) processing of 316 stainless steel and H13 tool steel. The cooling rates at the solid-liquid interface were measured over a range of conduction conditions. The length scale of the molten zone controls cooling rates during solidification in direct metal deposition. In LENS processing, the molten zone ranges from 0.5 mm in length to 1.5 mm, resulting in cooling rates at the solid-liquid interface ranging from 200 6,000 Ks-1.

  14. Changes in lens stiffness due to capsular opacification in accommodative lens refilling

    NARCIS (Netherlands)

    Nibourg, Lisanne M.; Sharma, Prashant K.; van Kooten, Theo G.; Koopmans, Steven A.

    Accommodation may be restored to presbyopic lenses by refilling the lens capsular bag with a soft polymer. After this accommodative lens refilling prevention of capsular opacification is a requirement, since capsular opacification leads to a decreased clarity of the refilled lens. It has been

  15. Exchange of tears under a contact lens is driven by distortions of the contact lens.

    Science.gov (United States)

    Maki, Kara L; Ross, David S

    2014-12-01

    We studied the flow of the post-lens tear film under a soft contact lens to understand how the design parameters of contact lenses can affect ocular health. When a soft contact lens is inserted, the blinking eyelid causes the lens to stretch in order to conform to the shape of the eye. The deformed contact lens acts to assume its un-deformed shape and thus generates a suction pressure in the post-lens tear film. In consequence, the post-lens tear fluid moves; it responds to the suction pressure. The suction pressure may draw in fresh fluid from the edge of the lens, or it may eject fluid there, as the lens reassumes its un-deformed shape. In this article, we develop a mathematical model of the flow of the post-lens tear fluid in response to the mechanical suction pressure of a deformed contact lens. We predict the amount of exchange of fluid exchange under a contact lens and we explore the influence of the eye's shape on the rate of exchange of fluid. © The Author 2014. Published by Oxford University Press on behalf of the Society for Integrative and Comparative Biology. All rights reserved. For permissions please email: journals.permissions@oup.com.

  16. Self-catalyst growth of novel GaN nanowire flowers on Si (111) using thermal evaporation technique

    Energy Technology Data Exchange (ETDEWEB)

    Saron, K.M.A., E-mail: kamalmohammedabdalla@yahoo.com [Nano-Optoelectronics Research and Technology Laboratory (NOR), School of Physics, Universiti Sains Malaysia, Penang 11800 (Malaysia); Hashim, M.R., E-mail: roslan@usm.my [Nano-Optoelectronics Research and Technology Laboratory (NOR), School of Physics, Universiti Sains Malaysia, Penang 11800 (Malaysia)

    2013-05-15

    We investigated the effect of substrate temperature on nanowire (NW) flower GaN epitaxial layers grown on catalyst-free Si (111) through physical vapor deposition via the thermal evaporation of GaN powder at 1150 °C in the absence of NH{sub 3} gas. The NW flowers were grown at various substrate temperatures from 1000 °C to 1100 °C for 60 min in N{sub 2} ambient. The surface morphology as well as the structural and optical properties of GaN NW flowers were examined by scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy, X-ray diffraction, and photoluminescence (PL). The results showed that the increase in substrate temperature resulted in a variation in crystal quality and surface morphology. SEM showed that the substrate temperature has a stronger effect on NW density and growth rate with respect to time. The average length of GaN flowers is estimated to be longer than 300 μm after 1 h at 1100 °C, which corresponds to a fast growth rate of more than 200 μm h{sup −1} at all substrate temperatures. The PL measurements showed strong near-band-edge (NBE) emission with a weak deep level emission. The green-yellow emission (GYE) can be attributed to N vacancies or to the V{sub Ga}–O{sub N}-complexes. The NBE peak exhibited a redshift with increasing substrate temperature, which results from the increase in strain level. The growth mechanism of the polycrystalline GaN NWs was also discussed. - Highlights: ► GaN nanowired flowers were grown on free-catalysts Si (111) using PVD. ► A higher temperature, higher uniformity, larger lengths and diameters of the NW flowers. ► As substrate temperature increases the diameters and growth rate of NWs increases. ► A lower temperature resulted in a high density and good crystal quality of GaN NWs. ► The increase in substrate temperature increased the redshift in UV band emission.

  17. Self-catalyst growth of novel GaN nanowire flowers on Si (111) using thermal evaporation technique

    International Nuclear Information System (INIS)

    Saron, K.M.A.; Hashim, M.R.

    2013-01-01

    We investigated the effect of substrate temperature on nanowire (NW) flower GaN epitaxial layers grown on catalyst-free Si (111) through physical vapor deposition via the thermal evaporation of GaN powder at 1150 °C in the absence of NH 3 gas. The NW flowers were grown at various substrate temperatures from 1000 °C to 1100 °C for 60 min in N 2 ambient. The surface morphology as well as the structural and optical properties of GaN NW flowers were examined by scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy, X-ray diffraction, and photoluminescence (PL). The results showed that the increase in substrate temperature resulted in a variation in crystal quality and surface morphology. SEM showed that the substrate temperature has a stronger effect on NW density and growth rate with respect to time. The average length of GaN flowers is estimated to be longer than 300 μm after 1 h at 1100 °C, which corresponds to a fast growth rate of more than 200 μm h −1 at all substrate temperatures. The PL measurements showed strong near-band-edge (NBE) emission with a weak deep level emission. The green-yellow emission (GYE) can be attributed to N vacancies or to the V Ga –O N -complexes. The NBE peak exhibited a redshift with increasing substrate temperature, which results from the increase in strain level. The growth mechanism of the polycrystalline GaN NWs was also discussed. - Highlights: ► GaN nanowired flowers were grown on free-catalysts Si (111) using PVD. ► A higher temperature, higher uniformity, larger lengths and diameters of the NW flowers. ► As substrate temperature increases the diameters and growth rate of NWs increases. ► A lower temperature resulted in a high density and good crystal quality of GaN NWs. ► The increase in substrate temperature increased the redshift in UV band emission

  18. Errors and corrections in the separation of spin-flip and non-spin-flip thermal neutron scattering using the polarization analysis technique

    International Nuclear Information System (INIS)

    Williams, W.G.

    1975-01-01

    The use of the polarization analysis technique to separate spin-flip from non-spin-flip thermal neutron scattering is especially important in determining magnetic scattering cross-sections. In order to identify a spin-flip ratio in the scattering with a particular scattering process, it is necessary to correct the experimentally observed 'flipping-ratio' to allow for the efficiencies of the vital instrument components (polarizers and spin-flippers), as well as multiple scattering effects in the sample. Analytical expressions for these corections are presented and their magnitudes in typical cases estimated. The errors in measurement depend strongly on the uncertainties in the calibration of the efficiencies of the polarizers and the spin-flipper. The final section is devoted to a discussion of polarization analysis instruments

  19. Studies on thermal decomposition of phenol binder using TG/DTG/DTA and FTIR-DRIFTS techniques in temperature range 20-500 °C

    Directory of Open Access Journals (Sweden)

    *Artur Bobrowski

    2018-03-01

    Full Text Available This paper presents results of thermoanalytical and structural research on phenolic binder used in foundry for the preparation of moulding sand. The binder has been prepared based on resole type phenolic resin with the addition of ester hardener. The aim of the study was to determine the structural changes taking place in the phenolic binder under the influence of temperature. Results show that in the investigated range of temperatures,phenolic binder exhibits three exothermic thermal effects accompanying the decomposition process. The test results using the Diffuse Reflectance Infrared Fourier Transform Spectroscopy (DRIFTS technique show that the addition of a hardener stabilizes the binder structure within methylene bridges. The reduction in the reaction rate observed in the DTA curve at about 330 癈 can be associated with the formation of gaseous products by decomposition of the binder or, as suggested by the literature data, the formation of triple bonds and CN-HCN groups.

  20. Use of Several Thermal Analysis Techniques to Study the Cracking of an Nitrile Butadiene Rubber (NBR) Insulator on the Booster Separation Motor (BSM) of the Space Shuttle

    Science.gov (United States)

    Wingard, Charles D.; Whitaker, Ann F. (Technical Monitor)

    2000-01-01

    Two different vendor rubber formulations have been used to produce the silica-filled NBR insulators for the BSM used on both of the Solid Rocket Boosters (SRBs) of the Space Shuttle. A number of lots of the BSM insulator in 1998-99 exhibited surface cracks and/or crazing. Each insulator is bonded to the BSM aluminum aft closure with an epoxy adhesive. Induced insulator stresses from adhesive cure are likely greatest where the insulator/adhesive contour is the greatest, thus showing increased insulator surface cracking in this area. Thermal analysis testing by Dynamic Mechanical Analyzer (DMA) and Thermomechanical Analysis (TMA) was performed on one each of the two vendor BSM insulators previously bonded that exhibited the surface cracking. The TMA data from the film/fiber technique yielded the most meaningful results, with thin insulator surface samples containing cracks having roughly the same modulus (stiffness) as thin insulator bulk samples just underneath.