WorldWideScience

Sample records for plate thermal thinning

  1. Methodical Specifics of Thermal Experiments with Thin Carbon Reinforced Plates

    Directory of Open Access Journals (Sweden)

    O. V. Denisov

    2015-01-01

    Full Text Available Polymer composite materials (CM are widely used in creation of large space constructions, especially reflectors of space antennas. Composite materials should provide high level of specific stiffness and strength for space structures. Thermal conductivity in reinforcement plane is a significant factor in case of irregular heating space antennas. Nowadays, data on CM reinforcement plane thermal conductivity are limited and existing methods of its defining are imperfect. Basically, traditional methods allow us to define thermal conductivity in perpendicular direction towards the reinforcement plane on the samples of round or rectangular plate. In addition, the thickness of standard samples is larger than space antenna thickness. Consequently, new methods are required. Method of contact heating, which was developed by BMSTU specialists with long hollow carbon beam, could be a perspective way. This article is devoted to the experimental method of contact heating on the thin carbon plates.Thermal tests were supposed to provide a non-stationary temperature field with a gradient being co-directional with the plane reinforcement in the material sample. Experiments were conducted in vacuum chamber to prevent unstructured convection. Experimental thermo-grams processing were calculated by 1-d thermal model for a thin plate. Influence of uncertainty of experimental parameters, such as (radiation emission coefficients of sample surface, glue, temperature sensors and uncertainty of sensors placement on the result of defined thermal conductivity has been estimated. New data on the thermal conductivity in reinforcement plane were obtained within 295 - 375 K temperature range, which can be used to design and develop reflectors of precision space antennas. In the future it is expedient to conduct tests of thin-wall plates from carbon fiber-reinforced plastic in wide temperature range, especially in the low-range temperatures.

  2. Thermal deformation in a thin circular plate due to a partially ...

    Indian Academy of Sciences (India)

    ric heat supply on the upper face. Deshmukh & Khobragade (2002) determined quasi-static thermal deflections in thin circular plates subjected to arbitrary initial temperatures on the lower face with the upper face at zero temperature and the fixed circular edge thermally insulated. Here, we extend the work of Noda et al ...

  3. Thermal deformation in a thin circular plate due to a partially ...

    Indian Academy of Sciences (India)

    Keywords. Transient problem; thermal deformation; heat conduction problem. Abstract. In this paper, we develop an integral transform to determine temperature distribution in a thin circular plate, subjected to a partially distributed and axisymmetric heat supply on the curved surface, and study the thermal deformation.

  4. Nonlinear response analysis and experimental verification for thin-walled plates to thermal-acoustic loads

    Directory of Open Access Journals (Sweden)

    Yundong SHA

    2017-12-01

    Full Text Available For large deflection strongly nonlinear response problem of thin-walled structure to thermal-acoustic load, thermal-acoustic excitation test and corresponding simulation analysis for clamped metallic thin-walled plate have been implemented. Comparing calculated values with experimental values shows the consistency and verifies the effectiveness of calculation method and model for thin-walled plate subjected to thermal-acoustic load. Then this paper further completes dynamic response calculation for the cross reinforcement plate under different thermal-acoustic load combinations. Based on the obtained time-domain displacement response, analyses about structure vibration forms are mainly focused on three typical motions of post-buckled plate, indicating that the relative strength between thermal load and acoustic load determines jump forms of plate. The Probability spectrum Density Functions (PDF of displacement response were drawn and analyzed by employing statistical analysis method, and it clearly shows that the PDF of post-buckled plate exhibits bimodal phenomena. Then the Power Spectral Density (PSD functions were used to analyze variations of response frequencies and corresponding peaks with the increase of temperatures, as well as how softening and hardening areas of the plate are determined. In the last section, this paper discusses the change laws of tensile stress and compressive stress in pre/post buckling areas, and gives the reasons for N glyph trend of the stress Root Mean Square (RMS. Keywords: Buckling, Experimental verification, Nonlinear response, Power spectral density, Probability spectrum density, Snap-through, Thermal-acoustic load, Thin-walled structure

  5. Experimental investigation of thermal loading of a horizontal thin plate using infrared camera

    Directory of Open Access Journals (Sweden)

    M.Y. Abdollahzadeh Jamalabadi

    2014-07-01

    Full Text Available This study reports the results of experimental investigations of the characteristics of thermal loading of a thin plate by discrete radiative heat sources. The carbon–steel thin plate is horizontally located above the heat sources. Temperature distribution of the plate is measured using an infrared camera. The effects of various parameters, such as the Rayleigh number, from 107 to 1011, the aspect ratio, from 0.05 to 0.2, the distance ratio, from 0.05 to 0.2, the number of heaters, from 1 to 24, the thickness ratio, from 0.003 to 0.005, and the thermal radiative emissivity, from 0.567 to 0.889 on the maximum temperature and the length of uniform temperature region on a thin plate are explored. The results indicate that the most effective parameters on the order of impact on the maximum temperature is Rayleigh number, the number of heat sources, the distance ratio, the aspect ratio, the surface emissivity, and the plate thickness ratio. Finally, the results demonstrated that there is an optimal distance ratio to maximize the region of uniform temperature on the plate.

  6. Inverse transient thermoelastic deformations in thin circular plates

    Indian Academy of Sciences (India)

    Inverse transient thermoelastic deformations in thin circular plates. 663 where α and E are the coefficient of linear thermal expansion and Young's modulus respec- tively. The boundary condition concerning the in-plane deformation is given by r = a, dF/dr = 0, F = 0. (9). The differential equation satisfied by the deflection ω(r, ...

  7. STABILITY ANALYSIS OF SSSS THIN RECTANGULAR PLATE ...

    African Journals Online (AJOL)

    This was achieved by truncating the two domain Taylor Maclaurin's series at the seventh term to evolve the general deflection polynomial function for thin rectangular plate continuum. Consequently, the SSSS plate boundary conditions were applied, reducing the polynomial function to four degrees of freedom function.

  8. Baking process of thin plate carbonaceous compact

    Energy Technology Data Exchange (ETDEWEB)

    Suzuki, Yoshio; Shimada, Toyokazu

    1987-06-27

    As a production process of a thin plate carbonaceous compact for separator of phosphoric acid fuel cell, there is a process to knead carbonaceous powder and thermosetting resin solution, to form and harden the kneaded material and then to bake, carbonize and graphitize it. However in this baking and carbonization treatment, many thin plate compacts are set in a compiled manner within a heating furnace and receive a heat treatment from their circumference. Since the above compacts to be heated tend generally to be heated from their peripheries, their baked conditions are not homogeneous easily causing the formation of cracks, etc.. As a process to heat and bake homogeneously by removing the above problematical points, this invention offers a process to set in a heating furnace a laminate consisting of the lamination of thin plate carbonaceous compacts and the heat resistant soaking plates which hold the upper and lower ends of the above lamination, to fill the upper and under peripheries of the laminate above with high heat conductive packing material and its side periphery with low heat conductive packing material respectively and to heat and sinter it. In addition, the invention specifies the high and low heat conductive packing materials respectively. (1 fig, 2 tabs)

  9. Casting/mold thermal contact heat transfer during solidification of Al-Cu-Si alloy (LM 21) plates in thick and thin molds

    Science.gov (United States)

    Prabhu, K. Narayan; Chowdary, Bheemappa; Venkataraman, N.

    2005-10-01

    Heat flow at the casting/mold interface was assessed and studied during solidification of Al-Cu-Si (LM 21) alloy in preheated cast iron molds of two different thicknesses, coated with graphite and alumina based dressings. The casting and the mold were instrumented with thermocouples connected to a computer controlled temperature data acquisition system. The thermal history at nodal locations in the mold and casting obtained during experimentation was used to estimate the heat flux by solving the one-dimensional inverse heat conduction problem. The cooling rate and solidification time were measured using the computer-aided cooling curve analysis data. The estimated heat flux transients showed a peak due to the formation of a stable solid shell, which has a higher thermal conductivity compared with the liquid metal in contact with the mold wall prior to the occurrence of the peak. The high values of heat flux transients obtained with thin molds were attributed to mold distortion due to thermal stresses. For thin molds, assumption of Newtonian heating yielded reliable interfacial heat transfer coefficients as compared with one-dimensional inverse modeling. The time of occurrence of peak heat flux increased with a decrease in the mold wall thickness and increase in the casting thickness.

  10. Experiments on Elastic Cloaking in Thin Plates

    Science.gov (United States)

    Stenger, Nicolas; Wilhelm, Manfred; Wegener, Martin

    2012-01-01

    Following a theoretical proposal [M. Farhat , Phys. Rev. Lett. 103, 024301 (2009)PRLTAO0031-900710.1103/PhysRevLett.103.024301], we design, fabricate, and characterize a cloaking structure for elastic waves in 1 mm thin structured polymer plates. The cloak consists of 20 concentric rings of 16 different metamaterials, each being a tailored composite of polyvinyl chloride and polydimethylsiloxane. By using stroboscopic imaging with a camera from the direction normal to the plate, we record movies of the elastic waves for monochromatic plane-wave excitation. We observe good cloaking behavior for carrier frequencies in the range from 200 to 400 Hz (one octave), in good agreement with a complete continuum-mechanics numerical treatment. This system is thus ideally suited for demonstration experiments conveying the ideas of transformation optics.

  11. Improvement of rolling 6 mm thin plates in plate rolling mill PT. Krakatau Posco

    Science.gov (United States)

    Pujiyanto, Hamdani

    2017-01-01

    A 6-mm thin plate is difficult to produce especially if the product requires wide size and high strength. Flatness is the main quality issue in rolling 6-mm plate using a 4-high reversing mill which use ±1100-mm work roll. Thus some methods are applied to overcome such issue in order to comply to customer quality requirement. Pre-rolling, rolling, and post-rolling conditions have to be considered comprehensively. Roll unit management will be the key factor before rolling condition. The roll unit itself has a significant impact on work roll crown wearness in relation with work roll intial crown and thermal crown. Work roll crown along with the modification of hydraulic gap control (HGC) could directly alter the flatness of the plate.

  12. Thin-Plate Forming by Thixo- and Rheoforging

    Directory of Open Access Journals (Sweden)

    Chul Kyu Jin

    2014-08-01

    Full Text Available Thin plates with a thickness of 1.2 mm are fabricated using two processes, thixoforging and rheoforging, which are semisolid forming techniques. The die design, formability, microstructure, and mechanical properties of the fabricated thin plates are analysed. A fan-shaped gate is designed by analysing the filling behaviour using semisolid material, and uniform filling behaviour of material is obtained by arranging nine overflows in product area. semisolid metal is prepared through a semisolid process in which reheating, a thixoprocess, and cooling with stirring, a rheoprocess, are applied. The semisolid material is injected into a forging die and is formed into thin plate at a punch speed of 300 mm/s and under a pressure of 100 MPa. Since semisolid material with a solid fraction below 45% has mainly small primary α-Al particles, the formability of the thin plate is improved. The formed thin plate also has good mechanical properties since the small and globular grains are evenly distributed. The thin plate formed from semisolid material with a solid fraction above 50% has poor mechanical properties owing to the large quantity of coarse primary α-Al particles. A rheoforged thin plate exhibits poorer mechanical properties than a thixoforged thin plate, but rheoforging produces a more precise thin plate.

  13. stability analysis of ssss thin rectangular plate using multi

    African Journals Online (AJOL)

    user

    The stability analysis of all four edges simply supported (SSSS) thin rectangular plate using multi-degrees of freedom (MDOF) Taylor ... polynomial function in plates' continuum analysis other than SDOF. In which .... The percentage differences (error) between this study, Ibearugbulem et. al and Ezeh et. al with of those of ...

  14. Omnidirectional broadband insulating device for flexural waves in thin plates

    CERN Document Server

    Climente, Alfonso; Sánchez-Dehesa, José

    2013-01-01

    This work presents a gradient index device for insulating from vibrations a circular area of a thin plate. The gradient of the refractive index is achieved by locally changing the thickness of the plate, exploiting in this way the thickness-dependence of the dispersion relation of flexural waves in thin plates. A well-like thickness profile in an annular region of the plate is used to mimic the combination of an attractive and repulsive potentials, focusing waves at its bottom and dissipating them by means of a properly designed absorptive layer placed on top of the plate. The central area is therefore isolated from vibrations while they are dissipated at the bottom of the well. Simulations have been done using the multilayer multiple scattering method and the results prove their broadband efficiency and omnidirectional properties.

  15. Free Transverse Vibration of Orthotropic Thin Trapezoidal Plate of Parabolically Varying Thickness Subjected to Linear Temperature Distribution

    Directory of Open Access Journals (Sweden)

    Arun Kumar Gupta

    2014-01-01

    Full Text Available The present paper deals with the free transverse vibration of orthotropic thin trapezoidal plate of parabolically varying thickness in x-direction subjected to linear temperature distribution in x-direction through a numerical method. The deflection function is defined by the product of the equations of the prescribed continuous piecewise boundary shape. Rayleigh-Ritz method is used to evaluate the fundamental frequencies. The equations of motion, governing the free transverse vibrations of orthotropic thin trapezoidal plates, are derived with boundary condition CSCS. Frequency corresponding to the first two modes of vibration is calculated for the orthotropic thin trapezoidal plate having CSCS edges for different values of thermal gradient, taper constant, and aspect ratio. The proposed method is applied to solve orthotropic thin trapezoidal plate of variable thickness with C-S-C-S boundary conditions. Results are shown by figures for different values of thermal gradient, taper constant, and aspect ratio for the first two modes of vibrations.

  16. Effective medium theory of thin-plate acoustic metamaterials.

    Science.gov (United States)

    Li, Pei; Yao, Shanshan; Zhou, Xiaoming; Huang, Guoliang; Hu, Gengkai

    2014-04-01

    Effective dynamic properties of acoustic metamaterials made of multilayered flexible thin-plates with periodically attached mass-spring resonators are studied. By using the transfer matrix method, the thin-plate acoustic metamaterial under the plane wave incidence is characterized by a homogeneous effective medium with anisotropic mass density. An approximate analytic expression of effective mass density is derived for a single-layer metamaterial in the normally incident case, and it is shown that the effective mass density can follow either Lorentz or Drude medium models. For the obliquely incident case, it is found that effective mass density is dependent on the lateral wave number of incident waves. Such spatial dispersion comes from the coincidence effect between the incident acoustic wave and flexural wave in the thin plate, and it occurs at much lower frequencies than that for a uniform plate without resonators. Based on the observed spatial dispersion, an acoustic device made of thin-plate metamaterials is designed for frequency-controlled acoustic directive radiation in the low-frequency regime.

  17. FINITE ELEMENT MODELING OF THIN CIRCULAR SANDWICH PLATES DEFLECTION

    Directory of Open Access Journals (Sweden)

    K. S. Kurachka

    2014-01-01

    Full Text Available A mathematical model of a thin circular sandwich plate being under the vertical load is proposed. The model employs the finite element method and takes advantage of an axisymmetric finite element that leads to the small dimension of the resulting stiffness matrix and sufficient accuracy for practical calculations. The analytical expressions for computing local stiffness matrices are found, which can significantly speed up the process of forming the global stiffness matrix and increase the accuracy of calculations. A software is under development and verification. The discrepancy between the results of the mathematical model and those of analytical formulas for homogeneous thin circularsandwich plates does not exceed 7%.

  18. Dynamic Analysis of the Titanium Alloy Plate under Thermal-acoustic Loadings

    Directory of Open Access Journals (Sweden)

    Zou Xuefeng

    2015-01-01

    Full Text Available Hypersonic vehicles structures suffer complex combined loadings generally. For the thin-walled structures and thermal protection systems of the aircraft, high temperature and intensity acoustic loadings are the significant factors that leading to their break. The object of this paper is typical simply supported titanium alloy plate, the finite element method was adopted to calculate the critical thermal buckling temperature the ordinal coupling method and Newmark method were adopted to calculate the thermal-acoustic dynamic response. Based on the FEM analysis, the power spectrum densities (PSD of center point was presented. Research results show that the thermal buckling of the typical simply supported titanium alloy plate occurs easily because of the low critical thermal buckling temperature, dynamic response of the thermal buckled plate suffering acoustic loads performs strong nonlinear characteristics and complex forms of exercise.

  19. The limitations on applying classical thin plate theory to thin annular plates clamped on the inner boundary

    Directory of Open Access Journals (Sweden)

    Daniel W. Zietlow

    2012-12-01

    Full Text Available The experimentally measured resonance frequencies of a thin annular plate with a small ratio of inner to outer radii and clamped on the inner boundary are compared to the predictions of classical thin-plate (CTP theory and a finite-element (FE model. The results indicate that, contrary to the conclusions presented in a number of publications, CTP theory does not accurately predict the frequencies of a relatively small number of resonant modes at lower frequencies. It is shown that these inaccuracies are attributable to shear deformations, which are thought to be negligible in thin plates and are neglected in CTP theory. Of particular interest is the failure of CTP theory to accurately predict the resonance frequency of the lowest vibrational mode, which was shifted approximately 30% by shear motion at the inner boundary.

  20. Thermally tunable ferroelectric thin film photonic crystals.

    Energy Technology Data Exchange (ETDEWEB)

    Lin, P. T.; Wessels, B. W.; Imre, A.; Ocola, L. E.; Northwestern Univ.

    2008-01-01

    Thermally tunable PhCs are fabricated from ferroelectric thin films. Photonic band structure and temperature dependent diffraction are calculated by FDTD. 50% intensity modulation is demonstrated experimentally. This device has potential in active ultra-compact optical circuits.

  1. Platonic scattering cancellation for bending waves in a thin plate

    KAUST Repository

    Farhat, Mohamed

    2014-04-10

    We propose an ultra-thin elastic cloak to control the scattering of bending waves in isotropic heterogeneous thin plates. The cloak design makes use of the scattering cancellation technique applied, for the first time, to the biharmonic operator describing the propagation of bending waves in thin plates. We first analyze scattering from hard and soft cylindrical objects in the quasistatic limit, then we prove that the scattering of bending waves from an object in the near and far-field regions can be suppressed significantly by covering it with a suitably designed coating. Beyond camouflaging, these findings may have potential applications in protection of buildings from earthquakes and isolating structures from vibrations in the motor vehicle industry.

  2. Towards an optimum design for thin film phase plates

    Energy Technology Data Exchange (ETDEWEB)

    Rhinow, Daniel, E-mail: daniel.rhinow@biophys.mpg.de

    2016-01-15

    A variety of physical phase plate designs have been developed to maximize phase contrast for weak phase objects in the transmission electron microscope (TEM). Most progress towards application in structural biology has been made with Zernike PPs consisting of a ~30 nm film of amorphous carbon with a central hole. Although problems such as beam-induced deterioration of Zernike PPs remain unsolved, it is likely that thin film phase plates will be applied routinely in TEM of ice-embedded biological specimens in the near future. However, the thick carbon film of thin film PPs dampens high-resolution information, which precludes their use for single-particle electron cryo-microscopy at atomic resolution. In this work, an improved design for a thin film phase plate is proposed, combining the advantages of Zernike PPs and 2D materials, such as graphene. The improved design features a disc of phase-shifting material mounted on an ultrathin support film. The proposed device imparts a phase shift only to electrons scattered to low angles, whereas contrast at high resolution is generated by conventional defocusing. The device maximizes phase contrast at low spatial frequencies, where defocus contrast is limiting, while damping of information at high spatial frequencies is avoided. Experiments demonstrate that the fabrication of such a device is feasible. - Highlights: • Thin film phase plates enable in-focus TEM imaging of biological specimens. • The thick amorphous carbon film causes damping of high-resolution information. • New thin film phase plate design imparts phase shift only to low spatial frequencies. • Improved design holds promise to facilitate cryo-EM of single particles.

  3. Thermal and mechanical modelling of convergent plate margins

    NARCIS (Netherlands)

    van den Beukel, P.J.

    1990-01-01

    In this thesis, the thermal and mechanical structure of convergent plate margins will be investigated by means of numerical modelling. In addition, we will discuss the implications of modelling results for geological processes such as metamorphism or the break-up of a plate at a convergent plate

  4. Thermal properties of methyltrimethoxysilane aerogel thin films

    Directory of Open Access Journals (Sweden)

    Leandro N. Acquaroli

    2016-10-01

    Full Text Available Aerogels are light and porous solids whose properties, largely determined by their nanostructure, are useful in a wide range of applications, e.g., thermal insulation. In this work, as-deposited and thermally treated air-filled silica aerogel thin films synthesized using the sol-gel method were studied for their thermal properties using the 3-omega technique, at ambient conditions. The thermal conductivity and diffusivity were found to increase as the porosity of the aerogel decreased. Thermally treated films show a clear reduction in thermal conductivity compared with that of as-deposited films, likely due to an increase of porosity. The smallest thermal conductivity and diffusivity found for our aerogels were 0.019 W m−1 K−1 and 9.8 × 10-9 m2 s−1. A model was used to identify the components (solid, gaseous and radiative of the total thermal conductivity of the aerogel.

  5. Thermal stresses and deflections of cross-ply laminated plates using refined plate theories

    Science.gov (United States)

    Khdeir, A. A.; Reddy, J. N.

    1991-01-01

    Exact analytical solutions of refined plate theories are developed to study the thermal stresses and deflections of cross-ply rectangular plates. The state-space approach in conjunction with the Levy method is used to solve exactly the governing equations of the theories under various boundary conditions. Numerical results of the higher-order theory of Reddy for thermal stresses and deflections are compared with those obtained using the classical and first-order plate theories.

  6. MATHEMATICAL SIMULATION OF WELDING DISTORTIONS IN THIN PLATES

    Directory of Open Access Journals (Sweden)

    Afshin Kheidari Monfared

    2011-01-01

    Full Text Available Welding is a crucial manufacturing process and widely used for manufacturing various products including ships, automobiles, trains and bridges. Welding distortions often occur in welded structures of thin plates due to relatively low stiffness and result in their warpage during assembly process and high manufacturing cost. Therefore, prediction and reduction of welding distortions are important in order to improve quality of welded structures. Welding distortion during the assembly process is caused not only by local shrinkage due to rapid heating and cooling. 3-D thermo-elastic-plastic finite element method (FEM has been used to simulate single-bead-on-plate welding with 1 mm thickness. Experiments have been carried out to prove the simulated results. Comparison of the experimental results and FEM simulation results has confirmed that the proposed method efficiently  predicts level of  welding distortions while making single-bead-on-plate welding with 1 mm thickness.

  7. Experimental Studies on the Fire Behaviour of High Performance Concrete Thin Plates

    DEFF Research Database (Denmark)

    Hulin, Thomas; Hodicky, Kamil; Schmidt, Jacob Wittrup

    2015-01-01

    pressure, stress concentrations, and thermo-mechanical energy accumulation in the tested specimens. Unexpectedly, spalling at the unexposed surface was observed during two of the tests, suggesting a potentially unusual, unwanted failure mode of very thin-plates during fire. On this basis it is recommended...... experimental investigations on the fire behaviour of HPC thin plates (20 or 30 mm thick) being used in lightweight structural sandwich elements. Tests were undertaken using a standard testing furnace and a novel heat-transfer rate inducing system (H-TRIS), recently developed at the University of Edinburgh....... The parametric assessment of the specimen performance included: thickness of the specimen, testing apparatus, and concrete mix (both with and without polypropylene fibres). The results verified the ability of H-TRIS to impose an equivalent thermal boundary condition to that imposed during a standard furnace test...

  8. A model for spalling of HPC thin plates exposed to fire

    DEFF Research Database (Denmark)

    Hulin, Thomas; Hodicky, Kamil; Schmidt, Jacob Wittrup

    2013-01-01

    to disclose the temperature distributions during the test. A non-linear coupled model for time dependent heat and mass transfer in concrete thin plates was used for temperature and pore pressure computations. Results from modelling and tests are compared and discussed. Moisture content was found......An experimental program was carried out to investigate the behaviour of high performance concrete (HPC) thin plates in fire for use in sandwich panels. To reveal the influence of moisture two initial moisture contents for wet and dry samples were examined. In addition, two thicknesses were used...... to be a critical parameter in the spalling process. The calculated pore pressure induced too low tensile stresses in the matrix to trigger failure, suggesting a major role played by thermal stresses...

  9. Experimentally validated thermal model of thin film NiTi

    Science.gov (United States)

    Favelukis, Jenna E.; Lavine, Adrienne S.; Carman, Gregory P.

    1999-06-01

    The primary focus of this work is to develop a new analytical approach for thermal modeling of Nickel Titanium (NiTi) shape memory alloy membranes undergoing both phase transformation and large deflections. This paper describes a thermal model of a NiTi plate or thin film, including all the modes of heat loss and latent heat dissipation during the phase transformation. This model is used to predict the NiTi temperature during cooling. The results are compared with experiments conducted on a NiTi plate and thin film (3 micrometers thick), and very good agreement is found. The thermal model is also used to predict the temperature response of a bubble actuator proposed for use in a forced flow environment. Using a 3 mm diameter, 3 micrometers thickness bubble under forced airflow conditions it is possible to achieve a frequency response faster than 300 Hz. Additional calculations were made to verify the structural stability of the actuator system. Predictions indicated that for specific geometries a pressure of at least 35 kPa can be supported by the NiTi membrane. Deflections of a bubble actuator are shown to be on the order of 10% of its diameter while the strain remains below 4%.

  10. Thin metastructures with engineered thermal expansion

    Science.gov (United States)

    Gdoutos, Eleftherios E.

    The geometry and constituent materials of metastructures can be used to engineer the thermal expansion coefficient. In this thesis, we design, fabricate, and test thin thermally stable metastructures consisting of bi-metallic unit cells and show how the coefficient of thermal expansion (CTE) of these metastructures can be finely and coarsely tuned by varying the CTE of the constituent materials and the unit cell geometry. Planar and three-dimensional finite element method modeling is used to drive the design and inform experiments, and predict the response of these metastructures. We demonstrate computationally the significance of out-of-plane effects in the metastructure response. We develop an experimental setup using digital image correlation and an infrared camera to experimentally measure full displacement and temperature fields during testing and accurately measure the metastructures' CTE. We experimentally demonstrate high aspect ratio metastructures of Ti/Al and Kovar/Al which exhibit near-zero and negative CTE, respectively. We demonstrate robust fabrication procedures for thermally stable samples with high aspect ratios in thin foil and thin film scales. We investigate the lattice structure and mechanical properties of thin films comprising a near-zero CTE metastructure. The mechanics developed in this work can be used to engineer metastructures of arbitrary CTE and can be extended to three dimensions.

  11. Experimental investigations of sandwich panels using high performance concrete thin plates exposed to fire

    DEFF Research Database (Denmark)

    Hulin, Thomas; Hodicky, Kamil; Schmidt, Jacob Wittrup

    2015-01-01

    Structural sandwich panels using thin high performance concrete (HPC) plates offer a possibility to address the modern environmental challenges faced by the construction industry. Fire resistance is a major necessity in structures using HPC. This paper presents experimental studies at elevated...... temperatures for panels with 30 mm thick plates stiffened by structural ribs, thick insulation layers, and steel shear connecting systems. Parametric variation assessing the role of each component of the sandwich structure was performed on unloaded specimens of reduced size. Full size walls were tested...... plate and one of them experienced heavy heat-induced spalling. Results highlighted insulation shear failure from differential thermal expansion at the interface with concrete. It suggests the existence of a high bond level between the two materials which might allow structural applications at early age...

  12. Investigation of acoustic field near to elastic thin plate using integral method

    Directory of Open Access Journals (Sweden)

    В.І. Токарев

    2004-01-01

    Full Text Available  Investigation of acoustic field near to elastic thin plate using  integral method The influence of boundary conditions on sound wave propagation, radiation and transmission through thin elastic plate is investigated. Necessary for that numerical model was found using the Helmholtz equation and equation of oscilated plate by means of integral formulation of the solution for acoustic fields near to elastic thin plate and for bending waves of small amplitudes.

  13. Buckling of Flat Thin Plates under Combined Loading

    Directory of Open Access Journals (Sweden)

    Ion DIMA

    2015-03-01

    Full Text Available This article aims to provide a quick methodology to determine the critical values of the forces applied to the central plane of a flat isotropic plate at which a change to the stable configuration of equilibrium occurs. Considering the variety of shapes, boundary conditions and loading combinations, the article does not intend to make an exhaustive presentation of the plate buckling. As an alternative, there will be presented only the most used configurations such as: rectangular flat thin plates, boundary conditions with simply supported (hinged or clamped (fixed edges, combined loadings with single compression or single shear or combination between them, compression and shear, with or without transverse loading, encountered at wings and control surfaces shell of fin and rudder or stabilizer and elevator. The reserve factor and the critical stresses will be calculated using comparatively two methods, namely the methodology proposed by the present article and ASSIST 6.6.2.0 – AIRBUS France software, a dedicated software to local calculations, for a simply supported plate under combined loading, compression on the both sides and shear.

  14. Thin-plate spline analysis of mandibular growth.

    Science.gov (United States)

    Franchi, L; Baccetti, T; McNamara, J A

    2001-04-01

    The analysis of mandibular growth changes around the pubertal spurt in humans has several important implications for the diagnosis and orthopedic correction of skeletal disharmonies. The purpose of this study was to evaluate mandibular shape and size growth changes around the pubertal spurt in a longitudinal sample of subjects with normal occlusion by means of an appropriate morphometric technique (thin-plate spline analysis). Ten mandibular landmarks were identified on lateral cephalograms of 29 subjects at 6 different developmental phases. The 6 phases corresponded to 6 different maturational stages in cervical vertebrae during accelerative and decelerative phases of the pubertal growth curve of the mandible. Differences in shape between average mandibular configurations at the 6 developmental stages were visualized by means of thin-plate spline analysis and subjected to permutation test. Centroid size was used as the measure of the geometric size of each mandibular specimen. Differences in size at the 6 developmental phases were tested statistically. The results of graphical analysis indicated a statistically significant change in mandibular shape only for the growth interval from stage 3 to stage 4 in cervical vertebral maturation. Significant increases in centroid size were found at all developmental phases, with evidence of a prepubertal minimum and of a pubertal maximum. The existence of a pubertal peak in human mandibular growth, therefore, is confirmed by thin-plate spline analysis. Significant morphological changes in the mandible during the growth interval from stage 3 to stage 4 in cervical vertebral maturation may be described as an upward-forward direction of condylar growth determining an overall "shrinkage" of the mandibular configuration along the measurement of total mandibular length. This biological mechanism is particularly efficient in compensating for major increments in mandibular size at the adolescent spurt.

  15. Thin shell vesicles composed of hydrophilic plate-like nanoparticles

    Science.gov (United States)

    Subramaniam, Anand; Wan, Jiandi; Gopinath, Arvind; Stone, Howard

    2011-03-01

    Nanopowders of graphene oxide, montmorillonite and laponite spontaneously delaminate into ultrathin nanoscopic plates when dispersed in water. These plates, which are typically ~ 1 nm thick and microns in lateral dimension, have found many uses as precursors to graphene, ceramics, layer-by-layer structures, and as structural modifiers of nanocomposites. Here we show that mechanical forces due to shear in a narrow gap can assemble hydrophilic plate-like particles on air bubbles, forming stable nanoplated armored bubbles. Translucent inorganic vesicles (vesicles defined here as closed thin-shelled structures with the same liquid inside and outside) of these particles are produced when the nanoplated armored bubbles are exposed to common water-miscible organic liquids and surfactants. These inorganic vesicles are mechanically robust, have walls that are about six nanometres thick, and are perforated with pores of submicron dimensions. We characterize the phenomenon and find that a wetting transition at the scale of the nanoparticles is the primary mechanism of formation. The discovery of these novel inorganic structures raises a wealth of questions of fundamental interest in materials and surface science.

  16. Mathematical model of temperature field distribution in thin plates during polishing with a free abrasive

    Directory of Open Access Journals (Sweden)

    Avilov Alex

    2017-01-01

    Full Text Available The purpose of this paper is to estimate the dynamic characteristics of the heating process of thin plates during polishing with a free abrasive. A mathematical model of the temperature field distribution in space and time according to the plate thickness is based on Lagrange equation of the second kind in the thermodynamics of irreversible processes (variation principle Bio. The research results of thermo elasticity of thin plates (membranes will allow to correct the modes of polishing with a free abrasive to receive the exact reflecting surfaces of satellites reflector, to increase temperature stability and the ability of radio signal reflection, satellite precision guidance. Calculations of temperature fields in thin plates of different thicknesses (membranes is held in the Excel, a graphical characteristics of temperature fields in thin plates (membranes show non-linearity of temperature distribution according to the thickness of thin plates (membranes.

  17. Fuel Cell Thermal Management Through Conductive Cooling Plates

    Science.gov (United States)

    Colozza, Anthony J.; Burke, Kenneth A.

    2008-01-01

    An analysis was performed to evaluate the concept of utilizing conductive cooling plates to remove heat from a fuel cell stack, as opposed to a conventional internal cooling loop. The potential advantages of this type of cooling system are reduced stack complexity and weight and increased reliability through the reduction of the number of internal fluid seals. The conductive cooling plates would extract heat from the stack transferring it to an external coolant loop. The analysis was performed to determine the required thickness of these plates. The analysis was based on an energy balance between the thermal energy produced within the stack and the heat removal from the cooling plates. To accomplish the energy balance, the heat flow into and along the plates to the cooling fluid was modeled. Results were generated for various numbers of cells being cooled by a single cooling plate. The results provided cooling plate thickness, mass, and operating temperature of the plates. It was determined that utilizing high-conductivity pyrolitic graphite cooling plates can provide a specific cooling capacity (W/kg) equivalent to or potentially greater than a conventional internal cooling loop system.

  18. Fire performance of basalt FRP mesh reinforced HPC thin plates

    DEFF Research Database (Denmark)

    Hulin, Thomas; Hodicky, Kamil; Schmidt, Jacob Wittrup

    2013-01-01

    An experimental program was carried out to investigate the influence of basalt FRP (BFRP) reinforcing mesh on the fire behaviour of thin high performance concrete (HPC) plates applied to sandwich elements. Samples with BFRP mesh were compared to samples with no mesh, samples with steel mesh...... on a linear increase of the volume of melted epoxy and the outflow of moisture from the concrete matrix. It was concluded that the use of a BFRP mesh to reinforce HPC exposed to fire reduces the mechanical strength despite a beneficial effect related to spalling....... and samples displaying a full sandwich structure. Final results confirmed the bond loss between concrete and BFRP mesh with temperature. The available void where the epoxy burnt away allowed the concrete matrix to release pressure and limit pore stresses, delaying spalling. It also reduced the mechanical...

  19. The complex variable reproducing kernel particle method for bending problems of thin plates on elastic foundations

    Science.gov (United States)

    Chen, L.; Cheng, Y. M.

    2017-09-01

    In this paper, the complex variable reproducing kernel particle method (CVRKPM) for solving the bending problems of isotropic thin plates on elastic foundations is presented. In CVRKPM, one-dimensional basis function is used to obtain the shape function of a two-dimensional problem. CVRKPM is used to form the approximation function of the deflection of the thin plates resting on elastic foundation, the Galerkin weak form of thin plates on elastic foundation is employed to obtain the discretized system equations, the penalty method is used to apply the essential boundary conditions, and Winkler and Pasternak foundation models are used to consider the interface pressure between the plate and the foundation. Then the corresponding formulae of CVRKPM for thin plates on elastic foundations are presented in detail. Several numerical examples are given to discuss the efficiency and accuracy of CVRKPM in this paper, and the corresponding advantages of the present method are shown.

  20. Thin-plate spline for deformations with specified derivatives

    Science.gov (United States)

    Bookstein, Fred L.; Green, William D. K.

    1993-06-01

    The thin-plate spline, originally introduced as a technique for surface interpolation, serves as a very useful image warping tool for maps driven by a small set of landmarks (discrete geometric points that correspond biologically between forms). Earlier work extended this formalism to incorporate about correspondence of edge-directions, or edgels, at the landmarks. The constrained maps are singular perturbations of a spline on the assigned landmarks corresponding to its augmentation by other landmarks at indeterminate, ultimately infinitesimal separation. The present manuscript recasts that earlier analysis in a new notation that greatly eases the extension to arbitrary linear (and linearizable) constraints on the derivatives of the warping function. We sketch the varieties of elementary warps to which these constraints lead and show some of their combinations. The algebra into which we have cast this extension seems capable of leading us even further beyond landmarks to incorporate information from derivatives of higher order than the first. This generalization may enrich the 'multiscale' approach to medical image analysis and may provide a bridge between two current approaches to the deformable-template problem--that of low-dimensional relatively global features and that of parameters distributed locally on a grid--that are not currently linked by any effective formalism.

  1. A theory for the fracture of thin plates subjected to bending and twisting moments

    Science.gov (United States)

    Hui, C. Y.; Zehnder, Alan T.

    1993-01-01

    Stress fields near the tip of a through crack in an elastic plate under bending and twisting moments are reviewed assuming both Kirchhoff and Reissner plate theories. The crack tip displacement and rotation fields based on the Reissner theory are calculated. These results are used to calculate the J-integral (energy release rate) for both Kirchhoff and Reissner plate theories. Invoking Simmonds and Duva's (1981) result that the value of the J-integral based on either theory is the same for thin plates, a universal relationship between the Kirchhoff theory stress intensity factors and the Reissner theory stress intensity factors is obtained for thin plates. Calculation of Kirchhoff theory stress intensity factors from finite elements based on energy release rate is illustrated. It is proposed that, for thin plates, fracture toughness and crack growth rates be correlated with the Kirchhoff theory stress intensity factors.

  2. Bifurcation Study of Thin Plate with an All-Over Breathing Crack

    Directory of Open Access Journals (Sweden)

    Lihua Chen

    2016-01-01

    Full Text Available An all-over breathing crack on the plate surface having arbitrary depth and location is assumed to be nonpropagating and parallel to one side of the plate. Based on a piecewise model, the nonlinear dynamic behaviors of thin plate with the all-over breathing crack are studied to analyze the effect of external excitation amplitudes and frequencies on cracked plate with different crack parameters (crack depth and crack location. Firstly, the mode shape functions of cracked thin plate are obtained by using the simply supported boundary conditions and the boundary conditions along the crack line. Then, natural frequencies and mode functions of the cracked plate are calculated, which are assessed with FEM results. The stress functions of thin plate with large deflection are obtained by the equations of compatibility in the status of opening and closing of crack, respectively. To compare with the effect of breathing crack on the plate, the nonlinear dynamic responses of open-crack plate and intact plate are analyzed too. Lastly, the waveforms, bifurcation diagrams, and phase portraits of the model are gained by the Runge-Kutta method. It is found that complex nonlinear dynamic behaviors, such as quasi-periodic motion, bifurcation, and chaotic motion, appear in the breathing crack plate.

  3. High Performance Flat Plate Solar Thermal Collector Evaluation

    Energy Technology Data Exchange (ETDEWEB)

    Rockenbaugh, Caleb [National Renewable Energy Lab. (NREL), Golden, CO (United States); Dean, Jesse [National Renewable Energy Lab. (NREL), Golden, CO (United States); Lovullo, David [National Renewable Energy Lab. (NREL), Golden, CO (United States); Lisell, Lars [National Renewable Energy Lab. (NREL), Golden, CO (United States); Barker, Greg [National Renewable Energy Lab. (NREL), Golden, CO (United States); Hanckock, Ed [National Renewable Energy Lab. (NREL), Golden, CO (United States); Norton, Paul [National Renewable Energy Lab. (NREL), Golden, CO (United States)

    2016-09-01

    This report was prepared for the General Services Administration by the National Renewable Energy Laboratory. The Honeycomb Solar Thermal Collector (HSTC) is a flat plate solar thermal collector that shows promising high efficiencies over a wide range of climate zones. The technical objectives of this study are to: 1) verify collector performance, 2) compare that performance to other market-available collectors, 3) verify overheat protection, and 4) analyze the economic performance of the HSTC both at the demonstration sites and across a matrix of climate zones and utility markets.

  4. Topological valley transport of plate-mode waves in a homogenous thin plate with periodic stubbed surface

    Directory of Open Access Journals (Sweden)

    Jiu-Jiu Chen

    2017-11-01

    Full Text Available The study for exotic topological effects of sound has attracted uprising interests in fundamental physics and practical applications. Based on the concept of valley pseudospin, we demonstrate the topological valley transport of plate-mode waves in a homogenous thin plate with periodic stubbed surface, where a deterministic two-fold Dirac degeneracy is form by two plate modes. We show that the topological property can be controlled by the height of stubs deposited on the plate. By adjusting the relative heights of adjacent stubs, the valley vortex chirality and band inversion are induced, giving rise to a phononic analog of valley Hall phase transition. We further numerically demonstrate the valley states of plate-mode waves with robust topological protection. Our results provide a new route to design unconventional elastic topological insulators and will significantly broaden its practical application in the engineering field.

  5. Topological valley transport of plate-mode waves in a homogenous thin plate with periodic stubbed surface

    Science.gov (United States)

    Chen, Jiu-Jiu; Huo, Shao-Yong; Geng, Zhi-Guo; Huang, Hong-Bo; Zhu, Xue-Feng

    2017-11-01

    The study for exotic topological effects of sound has attracted uprising interests in fundamental physics and practical applications. Based on the concept of valley pseudospin, we demonstrate the topological valley transport of plate-mode waves in a homogenous thin plate with periodic stubbed surface, where a deterministic two-fold Dirac degeneracy is form by two plate modes. We show that the topological property can be controlled by the height of stubs deposited on the plate. By adjusting the relative heights of adjacent stubs, the valley vortex chirality and band inversion are induced, giving rise to a phononic analog of valley Hall phase transition. We further numerically demonstrate the valley states of plate-mode waves with robust topological protection. Our results provide a new route to design unconventional elastic topological insulators and will significantly broaden its practical application in the engineering field.

  6. 3D modeling of thin wires interacting with thin plates: Extracting the singularity due to the loop wire self inductance

    Science.gov (United States)

    Abakar, A.; Meunier, G.; Coulomb, J.-L.; Zgainski, F.-X.

    2001-04-01

    The 3D modeling of thin structures by the finite element method leads to a high number of elements or elements of bad quality, which yields to badly conditioned problems. For the thin plates, shell formulations have been used by several authors. In the case of thin wires, we use a model of unmeshed conductor in which the current is unknown. Physics characteristics: resistance, inductance are integrated in the circuit equation. This article presents a method that extracts the inductance computation which introduced a singularity in the case of thin wires.

  7. The thermal state of the Arabian plate derived from heat flow measurements in Oman and Yemen

    Science.gov (United States)

    Rolandone, Frederique; Lucazeau, Francis; Leroy, Sylvie; Mareschal, Jean-Claude; Jorand, Rachel; Goutorbe, Bruno; Bouquerel, Hélène

    2013-04-01

    The dynamics of the Afar plume and the rifting of the Red Sea and the Gulf of Aden affect the present-day thermal regime of the Arabian plate. However, the Arabian plate is a Precambrian shield covered on its eastern part by a Phanerozoic platform and its thermal regime, before the plume and rifting activities, should be similar to that of other Precambrian shields with a thick and stable lithosphere. The first heat flow measurements in the shield, in Saudi Arabia, yielded low values (35-44 mW/m2), similar to the typical shields values. Recent heat flow measurements in Jordan indicate higher values (56-66 mW/m2). As part of the YOCMAL project (YOung Conjugate MArgins Laboratory), we have conducted heat flow measurements in southern and northern Oman to obtain 10 new heat flux values in the eastern Arabian plate. We also derived 20 heat flux values in Yemen and Oman by processing thermal data from oil exploration wells. The surface heat flux in these different locations is uniformly low (45 mW/m2). The heat production in samples from the Dhofar and Socotra Precambrian basement is also low (0.7 µW/m3). Differences in heat flow between the eastern (60 mW/m2) and the western (45 mW/m2) parts of Arabia reflect differences in crustal heat production as well as a higher mantle heat flux in the west. We have calculated a steady state geotherm for the Arabian platform that intersects the isentropic temperature profile at a depth of about 150 km, consistent with the seismic observations. Seismic tomography studies of the mantle beneath Arabia also show this east-west contrast. Seismic studies have shown that the lithosphere is rather thin, 100 km or less below the shield and 150 km below the platform. The lithospheric thickness for the Arabian plate is 150 km, and the progressive thinning near the Red Sea, caused by the thermal erosion of the plume material, is too recent to be detected at the surface. The Afar plume mostly affects the base of the Arabian lithosphere along

  8. Theoretical analysis based on fundamental functions of thin plate and experimental measurement for vibration characteristics of a plate coupled with liquid

    Science.gov (United States)

    Liao, Chan-Yi; Wu, Yi-Chuang; Chang, Ching-Yuan; Ma, Chien-Ching

    2017-04-01

    This study combined theoretical, experimental, and numerical analysis to investigate the vibration characteristics of a thin rectangular plate positioned horizontally at the bottom of a rectangular container filled with liquid. Flow field pressure was derived using an equation governing the behavior of incompressible fluids. Analytic solutions to vibrations in a thin plate in air served as the fundamental function of the thin plate coupled with liquid. We then used liquid pressure, and the out-of-plane deflection of the thin plate for the construction of frequency response functions for the analysis of vibration characteristics in the liquid-plate coupling system. Two experimental methods were employed to measure the vibration characteristics of the thin plate immersed in water. The first involved using sensors of polyvinylidene difluoride (PVDF) to measure transient signals of fluid-plate system subjected an impact at the thin plate. These were then converted to the frequency domain in order to obtain the resonant frequencies of the fluid-plate coupling system. The second method was amplitude-fluctuation electronic speckle pattern interferometry (AF-ESPI), which was used to measure the dynamic characteristics of the thin plate in the flow field. This method was paired with the image processing techniques, temporal speckle pattern interferometry (TSPI) and temporal standard deviation (TSTD), to obtain clear mode shapes of the thin plate and resonant frequencies. Comparison of the results from theoretical analysis, finite element method, and experimental measurements confirmed the accuracy of our theoretical analysis, which was superior to the conventional approach based on beam mode shape functions. The experimental methods proposed in this study can be used to measure the resonant frequencies of underwater thin plates, and clear mode shapes can be obtained using AF-ESPI. Our results indicate that the resonant frequencies of thin plates underwater are lower than

  9. Charging of carbon thin films in scanning and phase-plate transmission electron microscopy

    DEFF Research Database (Denmark)

    Hettler, Simon; Kano, Emi; Dries, Manuel

    2018-01-01

    A systematic study on charging of carbon thin films under intense electron-beam irradiation was performed in a transmission electron microscope to identify the underlying physics for the functionality of hole-free phase plates. Thin amorphous carbon films fabricated by different deposition techni...

  10. Measurement Techniques for Thermal Conductivity and Interfacial Thermal Conductance of Bulk and Thin Film Materials

    OpenAIRE

    Zhao, Dongliang; Qian, Xin; Gu, Xiaokun; Jajja, Saad Ayub; Yang, Ronggui

    2016-01-01

    Thermal conductivity and interfacial thermal conductance play crucial roles in the design of engineering systems where temperature and thermal stress are of concerns. To date, a variety of measurement techniques are available for both bulk and thin film solid-state materials with a broad temperature range. For thermal characterization of bulk material, the steady-state absolute method, laser flash diffusivity method, and transient plane source method are most used. For thin film measurement, ...

  11. Thermal performance optimization of a flat plate solar air heater using genetic algorithm

    Energy Technology Data Exchange (ETDEWEB)

    Varun; Siddhartha [Department of Mechanical Engineering, National Institute of Technology, Hamirpur 177 005 (H.P.) (India)

    2010-05-15

    Thermal performance of solar air heater is low and different techniques are adopted to increase the performance of solar air heaters, such as: fins, artificial roughness etc. In this paper an attempt has been done to optimize the thermal performance of flat plate solar air heater by considering the different system and operating parameters to obtain maximum thermal performance. Thermal performance is obtained for different Reynolds number, emissivity of the plate, tilt angle and number of glass plates by using genetic algorithm. (author)

  12. EVALUATION OF FLAT-PLATE PHOTOVOLTAIC THERMAL HYBRID SYSTEMS FOR SOLAR ENERGY UTILIZATION.

    Energy Technology Data Exchange (ETDEWEB)

    ANDREWS,J.W.

    1981-06-01

    The technical and economic attractiveness of combined photovoltaic/thermal (PV/T) solar energy collectors was evaluated. The study was limited to flat-plate collectors since concentrating photovoltaic collectors require active cooling and thus are inherently PV/T collectors, the only decision being whether to use the thermal energy or to dump it. it was also specified at the outset that reduction in required roof area was not to be used as an argument for combining the collection of thermal and electrical energy into one module. Three tests of economic viability were identified, all of which PV/T must pass if it is to be considered a promising alternative: PV/T must prove to be competitive with photovoltaic-only, thermal-only, and side-by-side photovoltaic-plus-thermal collectors and systems. These three tests were applied to systems using low-temperature (unglazed) collectors and to systems using medium-temperature (glazed) collectors in Los Angeles, New York, and Tampa. For photovoltaics, the 1986 DOE cost goals were assumed to have been realized, and for thermal energy collection two technologies were considered: a current technology based on metal and glass, and a future technology based on thin-film plastics. The study showed that for medium-temperature applications PV/T is not an attractive option in any of the locations studied. For low-temperature applications, PV/T appears to be marginally attractive.

  13. Simplified description of out-of-plane waves in thin annular elastic plates

    DEFF Research Database (Denmark)

    Zadeh, Maziyar Nesari; Sorokin, Sergey

    2013-01-01

    Dispersion relations are derived for the out-of-plane wave propagation in planar elastic plates with constant curvature using the classical Kirchhoff thin plate theory. The dispersion diagrams and the mode shapes are compared with their counterparts for a straight plate strip and the role...... of curvature is assessed for plates with unconstrained edges. Elementary Bernoulli–Euler theory for a beam of rectangular cross-section with the circular shape of its axis is also employed to analyze the wave guide properties of this structure in its out-of-plane deformation. The applicability range...... of the elementary beam theory is validated. The wave finite element method in the formulation of the three-dimensional elasticity theory is used to ensure that the comparison of dispersion diagrams is performed in the frequency range, where the classical thin plate theory is valid. Thus, the paper summarizes...

  14. Applicability of thin film phase plates in biological electron microscopy

    OpenAIRE

    Danev, Radostin; Nagayama, Kuniaki

    2006-01-01

    Presented is an evaluation of phase contrast techniques in transmission electron microscopy. The traditional defocus phase contrast is compared to two recently developed phase plate techniques. One is the Zernike phase contrast transmission electron microscope, the other is the Hilbert differential contrast thransmission electron microscope. The imaging characteristics of each technique are discussed. Phase plate techniques provide improved contrast for ice-embedded biological samples which a...

  15. Methods of localization of Lamb wave sources on thin plates

    Science.gov (United States)

    Turkaya, Semih; Toussaint, Renaud; Kvalheim Eriksen, Fredrik; Daniel, Guillaume; Grude Flekkøy, Eirik; Jørgen Måløy, Knut

    2015-04-01

    Signal localization techniques are ubiquitous in both industry and academic communities. We propose a new localization method on plates which is based on energy amplitude attenuation and inverted source amplitude comparison. This inversion is tested on synthetic data using Lamb wave propagation direct model and on experimental dataset (recorded with 4 Brüel & Kjær Type 4374 miniature piezoelectric shock accelerometers (1-26 kHz frequency range)). We compare the performance of the technique to the classical source localization algorithms, arrival time localization, time reversal localization, localization based on energy amplitude. Furthermore, we measure and compare the accuracy of these techniques as function of sampling rate, dynamic range, geometry, Signal to Noise Ratio, and we show that this very versatile technique works better than classical ones over the sampling rates 100kHz - 1MHz. Experimental phase consists of a glass plate having dimensions of 80cmx40cm with a thickness of 1cm. Generated signals due to a wooden hammer hit or a steel ball hit are captured by sensors placed on the plate on different locations with the mentioned sensors. Numerical simulations are done using dispersive far field approximation of plate waves. Signals are generated using a hertzian loading over the plate. Using imaginary sources outside the plate boundaries the effect of reflections is also included. This proposed method, can be modified to be implemented on 3d environments, monitor industrial activities (e.g boreholes drilling/production activities) or natural brittle systems (e.g earthquakes, volcanoes, avalanches).

  16. stability analysis of ssss thin rectangular plate using multi

    African Journals Online (AJOL)

    user

    Thereafter, Galerkin's model was applied to the classical governing differential equation of uniaxial plate buckling with the ... Rather than apply Ritz direct variational ... continuum analysis. This paper therefore, presents an improved Taylor. Maclaurin's solution approach that considered higher order functions in the Galerkin' ...

  17. Highly Mass-Sensitive Thin Film Plate Acoustic Resonators (FPAR

    Directory of Open Access Journals (Sweden)

    Ventsislav Yantchev

    2011-07-01

    Full Text Available The mass sensitivity of thin aluminum nitride (AlN film S0 Lamb wave resonators is theoretically and experimentally studied. Theoretical predictions based on modal and finite elements method analysis are experimentally verified. Here, two-port 888 MHz synchronous FPARs are micromachined and subsequently coated with hexamethyl-disiloxane(HMDSO-plasma-polymerized thin films of various thicknesses. Systematic data on frequency shift and insertion loss versus film thickness are presented. FPARs demonstrate high mass-loading sensitivity as well as good tolerance towards the HMDSO viscous losses. Initial measurements in gas phase environment are further presented.

  18. Creep bending of thin-walled shells and plates by consideration of finite deflections

    Science.gov (United States)

    Altenbach, H.; Naumenko, K.

    A phenomenological constitutive model for the characterization of creep-damage processes of metals is applied to the numerical analysis of thin-walled shells and plates. The governing equations of the theory of shallow shells are used taking into account geometrical nonlinearities connected with finite time-dependent deflections by moderate bending. The solutions of the initial-boundary value problem are obtained for thin rectangular plates in order to show the influence of geometrical nonlinearity on results of time-dependent deformation and stress redistribution as well as on estimations of the failure time.

  19. Active cloaking for clusters of pins in thin plates

    CERN Document Server

    O'Neill, Jane; Haslinger, Stewart; Movchan, Natasha; Craster, Richard

    2016-01-01

    This paper considers active cloaking of a square array of evenly spaced pins in a Kirchhoff plate in the presence of flexural waves. Active sources are distributed exterior to the cluster and are represented by the non-singular Green's function for the biharmonic operator. The complex amplitudes of the active sources, which cancel out selected multipole orders of the scattered field, are found by solving an algebraic system of equations. For frequencies in the zero-frequency stop band, we find that a small number of active sources located on a grid is sufficient for cloaking. For higher frequencies, we achieve efficient cloaking with the active sources positioned on a circle surrounding the cluster. We demonstrate the cloaking efficiency with several numerical illustrations, considering key frequencies from band diagrams and dispersion surfaces for a Kirchhoff plate pinned in a doubly periodic fashion.

  20. Regenerating silicon biosensors through thermal ablation with a hot plate

    Directory of Open Access Journals (Sweden)

    Stephane Leahy

    2015-12-01

    Full Text Available Biosensor development is time-consuming and expensive because it requires a great deal of prototyping and specialized experimental testing using, in many cases, one-time use chips. Several biosensor regeneration techniques have been proposed so that chips may be reused, but these techniques are not convenient for rapid prototyping and experimental testing. A convenient biosensor regeneration technique using thermal ablation with a hot plate is presented. Bound biological material is removed from a Poly-L-Lysine-functionalized silicon biosensor used for testing Escherichia coli by heating the biosensor to 370 °C for 10 min. Images and resonant frequency shifts indicate that regeneration is about 82% effective. This regeneration technique may be further improved by using a higher heating rate and a higher temperature.

  1. Vortex Formation Behind an Inclined 2-Dimensional Thin Flat Plate

    Science.gov (United States)

    Mohebi, Meraj; Wood, David H.; Martinuzzi, Robert J.

    2014-11-01

    Stereo Particle Image Velocimetry was used to measure the turbulent wake of a 2D flat plate inclined relative to a uniform stream as a heuristic model for airfoils and wind turbine blades at high incidence. Phase Averaging was performed to study the vortex dynamics and relate these to the force characteristics. Below 90°, immediately behind the plate, rounder and more organized trailing edge vortices form which possess higher circulation and are associated with higher Reynolds stresses than the counter-rotating, weaker and elongated leading edge vortices. The quasi-periodically shed vortices on the sides of the wake decay in strength at different rates to reach a circulation ratio of -1 within a distance less than 5 chords downstream of the plate for all angles. This equalization of vortex strength is related to an increase in turbulence diffusion, due to mostly-incoherent 3-dimensionality which progressively increases as the inclination angle is reduced, and convective transfer of vorticity between counter-rotating vortices. The wake experiences a sudden change in vortex formation mechanism at around 40°. At this angle, the frequency analysis on the signals of a pair of micro-pressure transducers in the wake also shows a discontinuity in the trends. This work was supported by NSERC Discovery grants to R. J. Martinuzzi and D. H. Wood.

  2. Selective thermal emission from thin-film metasurfaces

    Science.gov (United States)

    Streyer, W.; Law, S.; Mason, J.; Adams, D. C.; Rooney, G.; Jacobs, T.; Wasserman, D.

    2013-09-01

    The mid-infrared (mid-IR), as the spectral range where all finite temperature biological and mechanical objects emit thermal radiation, and where numerous molecular species have strong vibrational absorption resonances, is of significant importance for both security and sensing applications. The design of materials with engineered absorption resonances, which by Kirchoff's Law, should give strongly selective emission at the design resonance upon thermal excitation, allows for the control of the spectral character of the material's thermal emission. Designed as a thin film coating, these structures can be applied to grey-body emitters to shift the grey-body thermal emission into predetermined spectral bands, altering their appearance on a thermal imaging system. Here we demonstrate strongly selective mid-infrared absorption and thermal emission from three classes of subwavelength thin-film materials. First, we demonstrate selective thermal emission from patterned, commerciallyavailable steel films, via selective out-coupling of thermally-excited surface modes. Subsequently, we show nearperfect absorption (and strongly selective thermal emission) for wavelengths between 5 - 9μm with patterned metal-dielectric-metal structures. Finally, we demonstrate strong absorption from large area, unpatterned, thinfilm high-index dielectric coatings on highly-doped Si substrates, tunable across the mid-IR (5 - 12μm). Our results are compared to numerical simulations, as well as analytical models, with good agreement between experiments and models.

  3. Improvements of the smearing technique for cross-stiffened thin rectangular plates

    DEFF Research Database (Denmark)

    Luan, Yu; Ohlrich, Mogens; Jacobsen, Finn

    2011-01-01

    New developments in the simplified smearing technique for modeling vibrations of cross-stiffened, thin rectangular plates are presented. The computationally efficient smearing technique has been known for many years, but so far the accuracy of, say, predicted natural frequencies has been inadequa...

  4. Fingerprint Matching by Thin-plate Spline Modelling of Elastic Deformations

    NARCIS (Netherlands)

    Bazen, A.M.; Gerez, Sabih H.

    2003-01-01

    This paper presents a novel minutiae matching method that describes elastic distortions in fingerprints by means of a thin-plate spline model, which is estimated using a local and a global matching stage. After registration of the fingerprints according to the estimated model, the number of matching

  5. Study of plane wave impingement on a thin plate capable of deformation

    Science.gov (United States)

    Kisiel, Thomas K.

    1991-12-01

    This thesis models the effects in a fluid medium of a plane wave that has impinged upon a reinforced plate. The wave equation for pressure, and the equation of a thin plate combined with other equations are coupled at the interface between the fluid and the thin plate. The actual modeling is accomplished in a fortran computer program written to run on the Naval Postgraduate School's main frame computer. The program uses extensive finite differencing on a domain, assumed to be a small section of an infinite interface between the fluid and the plate, to simulate the deflection of the thin plate and the pressure disturbances in the fluid medium. To accomplish this, each of the above equations will be scaled or nondimensionalized. Additional finite differencing is explained which covers the special cases for the side boundaries of the fluid domain, and the artificial boundary created to model infinity. Different beam spacing is explored for its effect on the magnitude of the propagating modes of the scattered pressure wave.

  6. Effect of chamfer geometry on the pressure drop of perforated plates with thin orifices

    Energy Technology Data Exchange (ETDEWEB)

    Barros Filho, José A., E-mail: jabf@cdtn.br [Centro de Desenvolvimento da Tecnologia Nuclear, Comissão Nacional de Energia Nuclear, Av. Pres. Antônio Carlos, 6627, 30270-901 Belo Horizonte, MG (Brazil); Santos, André A.C., E-mail: aacs@cdtn.br [Centro de Desenvolvimento da Tecnologia Nuclear, Comissão Nacional de Energia Nuclear, Av. Pres. Antônio Carlos, 6627, 30270-901 Belo Horizonte, MG (Brazil); Navarro, Moysés A., E-mail: moysesnavarro@yahoo.com.br [Centro de Desenvolvimento da Tecnologia Nuclear, Comissão Nacional de Energia Nuclear, Av. Pres. Antônio Carlos, 6627, 30270-901 Belo Horizonte, MG (Brazil); Jordão, Elizabete, E-mail: bete@feq.unicamp.br [Faculdade de Engenharia Química, Universidade Estadual de Campinas – UNICAMP, Av. Albert Einstein, 500, 13.083-852 Campinas, SP (Brazil)

    2015-04-01

    Highlights: • CFD estimation of pressure drop of perforated plates with chamfered thin orifices. • Different chamfer geometric features evaluated. • Calculation validated against reduced scale experiments. - Abstract: Perforated plates with thin orifices is one of the options under considerations to be used in the debris filtering bottom end pieces for the next generation of fuel assemblies for the Brazilian nuclear plants. The increase in pressure drop can be drastically reduced by optimizing the chamfer geometries. This paper describes the development and validation of a procedure devised to use Computational Fluid Dynamics (CFD) to accurately estimate the pressure drop of water flow through perforated plates with chamfered thin orifices. The procedure comprises a scaled down calculation domain, grid configuration and a set of numerical solution parameters. The validation was performed against experiments with a set of plates with different chamfer geometric features like position (inlet, outlet and both sides), angles and sizes. Three turbulence models were evaluated with the standard k–ε giving the best result. For the range of parameters evaluated here the pressure drop decrease of a two sided chamfer plate can be estimated as a sum of both inlet and outlet chamfers individually. In both cases the pressure drop decreases rapidly for small chamfers and more slowly for larger chamfers. In the flat regions the chamfer angle has little influence at the inlet and is more important at outlet.

  7. Uncooled thin film pyroelectric IR detector with aerogel thermal isolation

    Energy Technology Data Exchange (ETDEWEB)

    Ruffner, J.A.; Clem, P.G.; Tuttle, B.A. [and others

    1998-01-01

    Uncooled pyroelectric IR imaging systems, such as night vision goggles, offer important strategic advantages in battlefield scenarios and reconnaissance surveys. Until now, the current technology for fabricating these devices has been limited by low throughput and high cost which ultimately limit the availability of these sensor devices. We have developed and fabricated an alternative design for pyroelectric IR imaging sensors that utilizes a multilayered thin film deposition scheme to create a monolithic thin film imaging element on an active silicon substrate for the first time. This approach combines a thin film pyroelectric imaging element with a thermally insulating SiO{sub 2} aerogel thin film to produce a new type of uncooled IR sensor that offers significantly higher thermal, spatial, and temporal resolutions at a substantially lower cost per unit. This report describes the deposition, characterization and optimization of the aerogel thermal isolation layer and an appropriate pyroelectric imaging element. It also describes the overall integration of these components along with the appropriate planarization, etch stop, adhesion, electrode, and blacking agent thin film layers into a monolithic structure. 19 refs., 8 figs., 6 tabs.

  8. Mobility activation in thermally deposited CdSe thin films

    Indian Academy of Sciences (India)

    Effect of illumination on mobility has been studied from the photocurrent decay characteristics of thermally evaporated CdSe thin films deposited on suitably cleaned glass substrate held at elevated substrate temperatures. The study indicates that the mobilities of the carriers of different trap levels are activated due to the ...

  9. Thin Thermal-Insulation Blankets for Very High Temperatures

    Science.gov (United States)

    Choi, Michael K.

    2003-01-01

    Thermal-insulation blankets of a proposed type would be exceptionally thin and would endure temperatures up to 2,100 C. These blankets were originally intended to protect components of the NASA Solar Probe spacecraft against radiant heating at its planned closest approach to the Sun (a distance of 4 solar radii). These blankets could also be used on Earth to provide thermal protection in special applications (especially in vacuum chambers) for which conventional thermal-insulation blankets would be too thick or would not perform adequately.

  10. Thermal analysis of thin layer boilover

    Energy Technology Data Exchange (ETDEWEB)

    Kozanoglu, Bulent [Universidad de las Americas, Puebla (Mexico); Mechanical Engineering Department, Cholula, Puebla (Mexico); Ferrero, Fabio; Munoz, Miguel; Arnaldos, Josep; Casal, Joaquim [Universitat Politecnica de Catalunya, Barcelona (Spain)

    2008-10-15

    A mathematical model is developed to simulate the thin layer boilover phenomenon. This model takes into account convective currents as well as conduction and radiation absorption through the fuel layer and is resolved numerically employing a scheme of Runge-Kutta, combined with the numerical method of lines. Solutions of the model showed a good agreement with the experimental data, both from this work and by other authors, demonstrating the importance of the convective currents. The model provided velocities of these currents, of the same order of magnitude as the values reported in the technical literature. Thickness of the remaining fuel and the interface temperature are correctly calculated by the model, allowing the prediction of the time required for the boilover to start. (orig.)

  11. Spin precession by pulsed inductive magnetometry in thin amorphous plates

    Energy Technology Data Exchange (ETDEWEB)

    Magni, Alessandro; Bottauscio, Oriano; Caprile, Ambra, E-mail: a.caprile@inrim.it; Celegato, Federica; Ferrara, Enzo; Fiorillo, Fausto [Istituto Nazionale di Ricerca Metrologica (INRIM), Electromagnetics Division, Torino 10135 (Italy)

    2014-05-07

    Broadband magnetic loss and damping behavior of Co-based amorphous ribbons and thin films have been investigated. The permeability and loss response of the transverse anisotropy ribbon samples in the frequency range DC to 1 GHz is interpreted in terms of combined and distinguishable contributions to the magnetization process by domain wall displacements and magnetization rotations. The latter alone are shown to survive at the highest frequencies, where the losses are calculated via coupled Maxwell and Landau–Lifshitz–Gilbert (LLG) equations. Remarkably high values of the LLG damping coefficient α = 0.1–0.2 are invoked in this theoretical prediction. Direct measurements of α by pulsed inductive microwave magnetometry are thus performed, both in these laminae and in amorphous films of identical composition, obtaining about one order of magnitude increase of the α value upon the 100 nm÷10 μm thickness range. This confirms that dissipation by eddy currents enters the LLG equation via large increase of the damping coefficient.

  12. Spin precession by pulsed inductive magnetometry in thin amorphous plates

    Science.gov (United States)

    Magni, Alessandro; Bottauscio, Oriano; Caprile, Ambra; Celegato, Federica; Ferrara, Enzo; Fiorillo, Fausto

    2014-05-01

    Broadband magnetic loss and damping behavior of Co-based amorphous ribbons and thin films have been investigated. The permeability and loss response of the transverse anisotropy ribbon samples in the frequency range DC to 1 GHz is interpreted in terms of combined and distinguishable contributions to the magnetization process by domain wall displacements and magnetization rotations. The latter alone are shown to survive at the highest frequencies, where the losses are calculated via coupled Maxwell and Landau-Lifshitz-Gilbert (LLG) equations. Remarkably high values of the LLG damping coefficient α = 0.1-0.2 are invoked in this theoretical prediction. Direct measurements of α by pulsed inductive microwave magnetometry are thus performed, both in these laminae and in amorphous films of identical composition, obtaining about one order of magnitude increase of the α value upon the 100 nm÷10 μm thickness range. This confirms that dissipation by eddy currents enters the LLG equation via large increase of the damping coefficient.

  13. Thermal characterization and modeling of ultra-thin silicon chips

    Science.gov (United States)

    Alshahed, Muhammad; Yu, Zili; Rempp, Horst; Richter, Harald; Harendt, Christine; Burghartz, Joachim N.

    2015-11-01

    Manufacturing ultra-thin chip is an emerging field in semiconductor technology that is driven by 3-D integrated circuits and flexible electronics. Unlike bulk silicon (Si) chips with thickness greater than 400 μm, the thermal management of ultra-thin Si chips with thickness smaller than 20 μm is challenging due to the increased lateral thermal resistance implying stringent cooling requirements. Therefore, a reasonable prediction of temperature gradients in such chips is necessary. In this work, a thermal chip is implemented in an ultra-thin 0.5 μm CMOS technology to be employed in surface steady-state and transient temperature measurement. Test chips are either packaged in a Pin Grid Array (PGA) ceramic package or attached to a flexible polyimide substrate. The experimental results show an on-chip temperature gradient of ∼15 °C for a dissipated power of 0.4 W in the case of the PGA package and ∼30 °C for the polyimide substrate. The time constants are ∼50 s and ∼1 s for the PGA and the polyimide packages respectively. The measurements are complemented by FEM simulations using ANSYS 14.5 workbench and spice simulations using an equivalent lumped-component thermal circuit model. The lumped-element thermal circuit model is then used for the surface temperature prediction, which is compared to measurement results.

  14. Dielectric barrier discharge ionization in characterization of organic compounds separated on thin-layer chromatography plates.

    Science.gov (United States)

    Cegłowski, Michał; Smoluch, Marek; Babij, Michał; Gotszalk, Teodor; Silberring, Jerzy; Schroeder, Grzegorz

    2014-01-01

    A new method for on-spot detection and characterization of organic compounds resolved on thin layer chromatography (TLC) plates has been proposed. This method combines TLC with dielectric barrier discharge ionization (DBDI), which produces stable low-temperature plasma. At first, the compounds were separated on TLC plates and then their mass spectra were directly obtained with no additional sample preparation. To obtain good quality spectra the center of a particular TLC spot was heated from the bottom to increase volatility of the compound. MS/MS analyses were also performed to additionally characterize all analytes. The detection limit of proposed method was estimated to be 100 ng/spot of compound.

  15. Degradation of dansyl polyamines on high-performance thin-layer chromatographic plates.

    Science.gov (United States)

    Rustenbeck, I; Löptien, D; Lenzen, S

    1995-05-05

    Using high-performance thin-layer chromatography with in situ quantitation to measure dansylated polyamines in the range of 1-20 pmol, we found that dansylated polyamines apparently react with the silica gel of the plates. The fluorescence of the dansyl polyamines diminished with increase in the time interval between application of a sample to the plate and start of the chromatographic separation. Conversely, the fluorescence at the site of application increased with the length of the time interval, indicating the formation of polar reaction products. If this reaction is not accounted for, considerable errors in quantitation of dansyl polyamines may occur.

  16. Charging of carbon thin films in scanning and phase-plate transmission electron microscopy.

    Science.gov (United States)

    Hettler, Simon; Kano, Emi; Dries, Manuel; Gerthsen, Dagmar; Pfaffmann, Lukas; Bruns, Michael; Beleggia, Marco; Malac, Marek

    2018-01-01

    A systematic study on charging of carbon thin films under intense electron-beam irradiation was performed in a transmission electron microscope to identify the underlying physics for the functionality of hole-free phase plates. Thin amorphous carbon films fabricated by different deposition techniques and single-layer graphene were studied. Clean thin films at moderate temperatures show small negative charging while thin films kept at an elevated temperature are stable and not prone to beam-generated charging. The charging is attributed to electron-stimulated desorption (ESD) of chemisorbed water molecules from the thin-film surfaces and an accompanying change of work function. The ESD interpretation is supported by experimental results obtained by electron-energy loss spectroscopy, hole-free phase plate imaging, secondary electron detection and x-ray photoelectron spectroscopy as well as simulations of the electrostatic potential distribution. The described ESD-based model explains previous experimental findings and is of general interest to any phase-related technique in a transmission electron microscope. Crown Copyright © 2017. Published by Elsevier B.V. All rights reserved.

  17. Failure characteristics of a thin metallic sandwich plate with metallic sheared dimple cores under low-velocity impact loading

    Energy Technology Data Exchange (ETDEWEB)

    Ahn, Dong Gyu; Jeong, Woo Chul [Chosun University, Gwangju (Korea, Republic of)

    2013-10-15

    The functionality and the performance of a lightweight sandwich plate with periodic cellular metal (PCM) cores are influenced by failure characteristics of the lightweight sandwich plate. The goal of this paper is to investigate the failure characteristics of a thin metallic sandwich plate with metallic sheared dimple cores under low-velocity impact loading through nonlinear finite element analysis. The influence of the imperfection mode of the cores on the impact response of a thin sandwich plate is examined to obtain a proper simulation model. Repeated finite element analyses are performed to examine the failure modes of the sandwich plate for different impact conditions. Normalized impact parameters are defined in order to generalize a dynamic failure map (DFM). DFMs of the thin metallic sandwich plate have been estimated via the regression analysis of critical impact conditions for each failure mode. In addition, the influence of the normalized impact parameters on the failure mode has been investigated using the DFM.

  18. Comparing wake structures behind a finite aspect ratio and an infinite span normal thin flat plate

    Science.gov (United States)

    Hemmati, Arman; Wood, David H.; Martinuzzi, Robert J.

    2014-11-01

    The wake of an infinite span (2D) thin flat plate and that of a finite aspect ratio, AR = 3.2, plate, both normal to a uniform stream, are compared using DNS at Re = 1200. For the 2D plate, three wake flow regimes are observed. Intervals of typical anti-symmetric Karman shedding (Regime M) are interrupted by intervals where the shear layer folding process first delayed (Regime L) and then accelerated, Regime H. The distinct flow patterns in these regimes have significant impact on lift and drag values, wake structure and instantaneous pressure loads. In contrast, only Regime M is observed for the AR = 3.2 plate. The presence of two lateral shear layers appears to maintain the Karman shedding. Compared to the infinite plate: the mean recirculation region shrinks by 45 % to 1.57H; the magnitude of the Reynolds Stresses drops significantly; Turbulent kinetic energy levels along the wake centerline and peak production and dissipation rates are significantly lower. Further, the three normal Reynolds stresses are comparable in magnitude. To better understand the impact of additional shear layers on the wake stability and resultant wake structures, the 3D structures will be reconstructed using DNS results. Pressure and stress distribution along the plate surfaces will also be examined. This work is supported by AITF and NSERC fellowship grants.

  19. Weakly nonlinear analysis of Rayleigh-Bénard convection in a non-Newtonian fluid between plates of finite conductivity: Influence of shear-thinning effects

    Science.gov (United States)

    Bouteraa, Mondher; Nouar, Chérif

    2015-12-01

    Finite-amplitude thermal convection in a shear-thinning fluid layer between two horizontal plates of finite thermal conductivity is considered. Weakly nonlinear analysis is adopted as a first approach to investigate nonlinear effects. The rheological behavior of the fluid is described by the Carreau model. As a first step, the critical conditions for the onset of convection are computed as a function of the ratio ξ of the thermal conductivity of the plates to the thermal conductivity of the fluid. In agreement with the literature, the critical Rayleigh number Rac and the critical wave number kc decrease from 1708 to 720 and from 3.11 to 0, when ξ decreases from infinity to zero. In the second step, the critical value αc of the shear-thinning degree above which the bifurcation becomes subcritical is determined. It is shown that αc increases with decreasing ξ . The stability of rolls and squares is then investigated as a function of ξ and the rheological parameters. The limit value ξc, below which squares are stable, decreases with increasing shear-thinning effects. This is related to the fact that shear-thinning effects increase the nonlinear interactions between sets of rolls that constitute the square patterns [M. Bouteraa et al., J. Fluid Mech. 767, 696 (2015), 10.1017/jfm.2015.64]. For a significant deviation from the critical conditions, nonlinear convection terms and nonlinear viscous terms become stronger, leading to a further diminution of ξc. The dependency of the heat transfer on ξ and the rheological parameters is reported. It is consistent with the maximum heat transfer principle. Finally, the flow structure and the viscosity field are represented for weakly and highly conducting plates.

  20. Sandwich panels with high performance concrete thin plates at elevated temperatures

    DEFF Research Database (Denmark)

    Hulin, Thomas; Hodicky, Kamil; Schmidt, Jacob Wittrup

    2015-01-01

    Performance of conventional load-carrying sandwich structures made of concrete can be improved by the use of high performance concrete (HPC) plates of thin sections (30 mm), linked by shear connectors ensuring the composite behaviour of the structure. This paper proposes the application...... concerned HMT modelling and elastic stress analysis with nonlinear temperature effects of a full size loaded sandwich wall, qualitatively assessing the location of critically stressed zones. Modelling output was compared to published experimental results. The model reproduced experimental temperature...

  1. Hydrodynamic resistance of the friction plates with longitudinal mikroborizdkamy and thin elastic coating

    Directory of Open Access Journals (Sweden)

    В.І. Коробов

    2008-03-01

    Full Text Available  Weight measurements in a water tunnel have shown that there exist a range of parameters of longitudinally fine-ribbed surface such that turbulent friction in flow over the surface is less then that over a smooth flat plate of the same projected area. Damping coating made from the thin layer of an elastic material and have interior longitudinal ribs of rigidity (overturn riblets is more effective than usual riblets.

  2. Shape derivative of the energy functional for the bending of elastic plates with thin defects

    Science.gov (United States)

    Shcherbakov, V. V.

    2017-10-01

    The paper deals with an equilibrium problem for a homogeneous isotropic elastic plate with a thin rigid inclusion and interfacial crack. We provide an explicit formula for the first shape derivative of the energy functional in the direction of a given vector field by means of a volume integral. For specific examples of the vector field, we derive some representations of the formula in terms of path-independent contour integrals.

  3. Microstructures and Mechanical Properties of Austempering SUS440 Steel Thin Plates

    Directory of Open Access Journals (Sweden)

    Cheng-Yi Chen

    2016-02-01

    Full Text Available SUS440 is a high-carbon stainless steel, and its martensite matrix has high heat resistance, high corrosion resistance, and high pressure resistance. It has been widely used in mechanical parts and critical materials. However, the SUS440 martempered matrix has reliability problems in thin plate applications and thus research uses different austempering heat treatments (tempering temperature: 200 °C–400 °C to obtain a matrix containing bainite, retained austenite, martensite, and the M7C3 phase to investigate the relationships between the resulting microstructure and tensile mechanical properties. Experimental data showed that the austempering conditions of the specimen affected the volume fraction of phases and distribution of carbides. After austenitizing heat treatment (1080 °C for 30 min, the austempering of the SUS440 thin plates was carried out at a salt-bath temperature 300 °C for 120 min and water quenching was then used to obtain the bainite matrix with fine carbides, with the resulting material having a higher tensile fracture strength and average hardness (HRA 76 makes it suitable for use as a high-strength thin plate for industrial applications.

  4. Low thermal emissivity surfaces using AgNW thin films

    Science.gov (United States)

    Pantoja, Elisa; Bhatt, Rajendra; Liu, Anping; Gupta, Mool C.

    2017-12-01

    The properties of silver nanowire (AgNW) films in the optical and infrared spectral regime offer an interesting opportunity for a broad range of applications that require low-emissivity coatings. This work reports a method to reduce the thermal emissivity of substrates by the formation of low-emissivity AgNW coating films from solution. The spectral emissivity was characterized by thermal imaging with an FLIR camera, followed by Fourier transform infrared spectroscopy. In a combined experimental and simulation study, we provide fundamental data of the transmittance, reflectance, haze, and emissivity of AgNW thin films. Emissivity values were finely tuned by modifying the concentration of the metal nanowires in the films. The simulation models based on the transfer matrix method developed for the AgNW thin films provided optical values that show a good agreement with the measurements.

  5. Thermally grown thin nitride films as a gate dielectric

    CERN Document Server

    Shin, H C; Hwang, T K; Lee, K R

    1998-01-01

    High-quality very thin films ( <=6 nm) of silicon nitride were thermally grown in ammonia atmosphere with an IR (Infrared) gold image furnace. As-grown nitride film was analyzed using AES(Auger Emission Spectroscopy). Using MIS (Metal-Insulator-Semiconductor) devices, the growth rate was calculated using CV (Capacitance-Voltage) measurements and various electrical characteristics were obtained using CV, IV (Current-Voltage), trapping, time-dependent breakdown, high-field stress, constant current injection stress and dielectric breakdown techniques. These characteristics showed that very thin thermal silicon nitride films can be used as gate dielectrics for future highly scaled-down ULSI (Ultra Large Scale Integrated) devices, especially for EEPROM (Electrically Erasable and Programmable ROM)'s.

  6. A pinned or free-floating rigid plate on a thin viscous film

    KAUST Repository

    Trinh, Philippe H.

    2014-11-11

    © 2014 Cambridge University Press. A pinned or free-floating rigid plate lying on the free surface of a thin film of viscous fluid, which itself lies on top of a horizontal substrate that is moving to the right at a constant speed is considered. The focus of the present work is to describe how the competing effects of the speed of the substrate, surface tension, viscosity, and, in the case of a pinned plate, the prescribed pressure in the reservoir of fluid at its upstream end, determine the possible equilibrium positions of the plate, the free surface, and the flow within the film. The present problems are of interest both in their own right as paradigms for a range of fluid-structure interaction problems in which viscosity and surface tension both play an important role, and as a first step towards the study of elastic effects.

  7. Thermal Stress Cracking of Slide-Gate Plates in Steel Continuous Casting

    Science.gov (United States)

    Lee, Hyoung-Jun; Thomas, Brian G.; Kim, Seon-Hyo

    2016-04-01

    The slide-gate plates in a cassette assembly control the steel flow through the tundish nozzle, and may experience through-thickness cracks, caused by thermal expansion and/or mechanical constraint, leading to air aspiration and safety concerns. Different mechanisms for common and rare crack formation are investigated with the aid of a three-dimensional finite-element model of thermal mechanical behavior of the slide-gate plate assembly during bolt pretensioning, preheating, tundish filling, casting, and cooling stages. The model was validated with previous plant temperature measurements of a ladle plate during preheating and casting, and then applied to a typical tundish-nozzle slide-gate assembly. The formation mechanisms of different types of cracks in the slide-gate plates are investigated using the model and evaluated with actual slide-gate plates at POSCO. Common through-thickness radial cracks, found in every plate, are caused during casting by high tensile stress on the outside surfaces of the plates, due to internal thermal expansion. In the upper plate, these cracks may also arise during preheating or tundish filling. Excessive bolt tightening, combined with thermal expansion during casting may cause rare radial cracks in the upper and lower plates. Rare radial and transverse cracks in middle plate appear to be caused during tundish filling by impingement of molten steel on the middle of the middle plate that generates tensile stress in the surrounding refractory. The mechanical properties of the refractory, the bolt tightening conditions, and the cassette/plate design are all important to service life.

  8. The Combinations of Thermal and Load Stresses for the Onset of Permanent Buckling in Plates

    Science.gov (United States)

    Zender, George W; Pride, Richard A

    1957-01-01

    A simple and practical method for evaluating the onset of permanent buckling in plates in the presence of combined thermal and compressive load stresses is outlined. A particular application of the method shows reasonable agreement with tests of 17-7 PH stainless-steel square tubes. The results indicate that the compressive load stress which the plate can support at the onset of permanent buckling is substantially reduced as the temperature difference of the plate and adjoining members increases.

  9. DESIGN AND THERMAL ANALYSIS OF FIXED AND TRACKING FLAT PLATE COLLECTORS

    OpenAIRE

    *Sudarshan T A

    2016-01-01

    This paper focuses on Thermal efficiency analysis of flat plate collectors. The instantaneous efficiency for a collector over a day is calculated. Application of solar energy for domestic and industrial heating purposes has been become very popular. However the effectiveness of presently used fixed flat plate collectors is low due to the moving nature of the energy source. In the present work, an attempt has been made to compare the performance of fixed flat plate water heater with that of he...

  10. A Novel Heat Pipe Plate for Passive Thermal Control of Fuel Cells Project

    Data.gov (United States)

    National Aeronautics and Space Administration — This SBIR project aims to develop a lightweight, highly thermally and electrically conductive heat pipe plate for passive removal of the heat from the individual...

  11. Study of the temperature distribution on welded thin plates of duplex steel to be used for the external clad of a cask for transportation of radiopharmaceuticals products

    Energy Technology Data Exchange (ETDEWEB)

    Betini, Evandro G.; Ceoni, Francisco C.; Mucsi, Cristiano S.; Politano, Rodolfo; Rossi, Jesualdo L., E-mail: egbetini@ipen.br, E-mail: fceoni@hotmail.com, E-mail: csmucsi@ipen.br, E-mail: politano@ipen.br, E-mail: jelrossi@ipen.br [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil); Orlando, Marcos T.D., E-mail: mtdorlando@gmail.com [Universidade Federal do Espirito Santo (CCE/DFIS/UFES), Vitoria, ES (Brazil). Centro de Ciencias Exatas. Departamento de Fisica

    2015-07-01

    The clad material for a proprietary transport device for radiopharmaceutical products is the main focus of the present work. The production of {sup 99}Mo-{sup 99m}Tc transport cask requires a receptacle or cask where the UNS S32304 duplex steel sheet has shown that it meets high demands as the required mechanical strength and the spread of impact or shock waves mitigation. This work reports the experimental efforts in recording the thermal distribution on autogenous thin plates of UNS S32304 steel during welding. The UNS S32304 duplex steel is the most probable candidate for the external clad of the containment package for the transport of radioactive substances so it is highly relevant the understanding of all its physical parameters and its behavior under the thermal cycle imposed by a welding process. For the welding of the UNS S32304 autogenous plates the GTAW (gas tungsten arc welding) process was used with a pure argon arc protection atmosphere in order to simulate a butt joint weld on a thin duplex steel plate without filler metal. The thermal cycles were recorded by means of K-type thermocouples embedded by electrical spot welding near the weld region and connected to a multi-channel data acquisition system. The obtained results validate the reliability of the experimental apparatus for the future complete analysis of the welding experiment and further comparison to numerical analysis. (author)

  12. Thermal Sensor Arrays for The Combinatorial Analysis of Thin Films

    Science.gov (United States)

    McCluskey, Patrick James

    2011-12-01

    Membrane-based thermal sensor arrays were developed for the high-throughput analysis of the thermophysical properties of thin films. The continuous growth of integrated circuits and microelectromechanical systems, as well as the development of functional materials and the optimization of materials properties, have produced the need for instruments capable of fast materials screening and analysis at reduced length scales. Two instruments were developed based on a similar architecture, one to measure thermal transport properties and the other to perform calorimetry measurements. Both have the capability to accelerate the pace of materials development and understanding using combinatorial measurement methods. The shared architecture of the instruments consists of a silicon-based micromachined array of thermal sensors. Each sensor consists of a SiN X membrane and a W heating element that also serves as a temperature gauge. The array design allows the simultaneous creation of a library of thin film samples by various deposition techniques while systematically varying a parameter of interest across the device. The membrane-based sensors have little thermal mass making them extremely sensitive to changes in thermal energy. The nano-thermal transport array has an array of sensors optimized for sensitivity to heat loss. The heat loss is determined from the temperature response of the sensor to an applied current. An analytical model is used with a linear regression analysis to fit the thermal properties of the samples to the temperature response. The assumptions of the analytical model are validated with a finite element model. Measured thermal properties include specific heat, thermal effusivity, thermal conductivity, and emissivity. The technique is demonstrated by measuring the thermal transport properties of sputter deposited Cu multilayers with a total film thickness from 15 to 470 nm. The experimental results compare well to a theory based on electronic thermal

  13. Correction on the influence of thermal contact resistance in thermal conductivity measurements using the guarded hot plate method

    Directory of Open Access Journals (Sweden)

    Stepanić Nenad

    2009-01-01

    Full Text Available This work considers the influence of finite thermal contact resistances which exist in thermal conductivity measurements of homogeneous and poor thermal conductive materials using the guarded hot plate method. As an example of correction method proposed in this work, different experimental results obtained from a standard reference material sample (with the conductivity of about 1 W/mK have been presented.

  14. Measurement of the thermal conductivity of thin insulating anisotropic material with a stationary hot strip method

    Science.gov (United States)

    Jannot, Yves; Degiovanni, Alain; Félix, Vincent; Bal, Harouna

    2011-03-01

    This paper presents a method dedicated to the thermal conductivity measurement of thin insulating anisotropic materials. The method is based on three hot-strip-type experiments in which the stationary temperature is measured at the center of the hot strip. A 3D model of the heat transfer in the system is established and simulated to determine the validity of a 2D transfer hypothesis at the center of the hot strip. A simplified 2D model is then developed leading to the definition of a geometrical factor calculable from a polynomial expression. A very simple calculation method enabling the estimation of the directional thermal conductivities from the three stationary temperature measurements and from the geometrical factor is presented. The uncertainties on each conductivity are estimated. The method is then validated by measurements on polyethylene foam and Ayous (anistropic low-density tropical wood); the estimated values of the thermal conductivities are in good agreement with the values estimated using the hot plate and the flash method. The method is finally applied on a thin super-insulating fibrous material for which no other method is able to measure the in-plane conductivity.

  15. Nano-oxide thin films deposited via atomic layer deposition on microchannel plates.

    Science.gov (United States)

    Yan, Baojun; Liu, Shulin; Heng, Yuekun

    2015-01-01

    Microchannel plate (MCP) as a key part is a kind of electron multiplied device applied in many scientific fields. Oxide thin films such as zinc oxide doped with aluminum oxide (ZnO:Al2O3) as conductive layer and pure aluminum oxide (Al2O3) as secondary electron emission (SEE) layer were prepared in the pores of MCP via atomic layer deposition (ALD) which is a method that can precisely control thin film thickness on a substrate with a high aspect ratio structure. In this paper, nano-oxide thin films ZnO:Al2O3 and Al2O3 were prepared onto varied kinds of substrates by ALD technique, and the morphology, element distribution, structure, and surface chemical states of samples were systematically investigated by scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), X-ray diffraction (XRD), and X-ray photoemission spectroscopy (XPS), respectively. Finally, electrical properties of an MCP device as a function of nano-oxide thin film thickness were firstly studied, and the electrical measurement results showed that the average gain of MCP was greater than 2,000 at DC 800 V with nano-oxide thin film thickness approximately 122 nm. During electrical measurement, current jitter was observed, and possible reasons were preliminarily proposed to explain the observed experimental phenomenon.

  16. Piezoelectric T-matrix approach and multiple scattering of electroacoustic waves in thin plates

    Science.gov (United States)

    Darabi, Amir; Ruzzene, Massimo; Leamy, Michael J.

    2017-12-01

    Metamaterial-enhanced harvesting (MEH) of wave energy in thin plates and other structures has appeared recently for powering small sensors and devices. To support continued MEH concept development, this paper proposes a fully coupled T-matrix formulation for analyzing scattering of incident wave energy from a piezoelectric patch attached to a thin plate. More generally, the T-matrix represents an input–output relationship between incident and reflected waves from inclusions in a host layer, and is introduced herein for a piezoelectric patch connected to an external circuit. The utility of a T-matrix formalism is most apparent in scenarios employing multiple piezoelectric harvesters, where it can be re-used with other T-matrices (such as those previously formulated for rigid, void, and elastic inclusions) in a multiple scattering context to compute the total wavefield and other response quantities, such as harvested power. Following development of the requisite T-matrix, harvesting in an example funnel-shaped metamaterial waveguide structure is predicted using the multiple scattering approach. Enhanced wave energy harvesting predictions are verified through comparisons to experimental results of a funnel-shaped waveguide formed by placing rigid aluminum inclusions in, and multiple piezoelectric harvesters on, a Lexan plate. Good agreement with predicted response quantities is noted.

  17. Thermally Induced Chain Orientation for Improved Thermal Conductivity of P(VDF-TrFE) Thin Films

    Energy Technology Data Exchange (ETDEWEB)

    Green, Peter [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Zhao, Junnan [University of Michigan; Tan, Aaron C. [University of Michigan

    2017-09-29

    The potential for polymer thin films to be used as coatings or dielectrics is limited by their low thermal conductivity, ..kappa... However, there have been very limited studies on ..kappa.. enhancement for polymer thin films. In this work, we show that the out-of-plane ..kappa.. of a poly(vinylidene fluoride-trifluoroethylene) (P(VDF-TrFE)) thin film can be enhanced when it undergoes the appropriate thermal annealing conditions. When the film is annealed above its melting temperature, we achieve a 300-400% increase in ..kappa.. across the measured temperature range, compared to the as-cast film. We attribute this enhancement to the extensive ordering of polymer backbone chains perpendicular to the substrate during the melt-recrystallization process.

  18. Friction properties and film strength of C60 fullerene thin films deposited by ion plating method; Ion plating C60 fullerene usumaku no masatsu tokusei to maku kyodo

    Energy Technology Data Exchange (ETDEWEB)

    Hironaka, S. [Tokyo Institute of Technology, Tokyo (Japan). Faculty of Engineering; Asakawa, T.; Yoshimoto, M.; Koinuma, H. [Tokyo Institute of Technology, Tokyo (Japan). Materials and Structures Laboratory

    1997-09-01

    The structure and mechanical properties of the C60-based thin films were studied which were fabricated from C60 powder on various substrates by vacuum evaporation and rf ion plating methods. The thin film coating by every method considerably reduces the original friction coefficient showing a lubrication effect. The thin film including its decomposed carbon by ion plating method is effective in preserving low friction for a long time. For comparison with vacuum evaporation method, the thin film was prepared by ion plating of as low as 0.13Pa in plasma generating pressure. It was suggested that C60 is hardly decomposed by optimizing pressure and rf power, and it is possible to fabricate the thin films with more excellent surface morphology and dynamic characteristics than those by vacuum evaporation method. It is also possible to fabricate the thin film with various C60/amorphous carbon matrix ratios by controlling rf power, and this film is regarded as a film with quantum holes of 0.7nm, showing the possibility of new functional materials. 14 refs., 12 figs., 2 tabs.

  19. Solar tests of aperture plate materials for solar thermal dish collectors

    Science.gov (United States)

    Jaffe, L. D.

    1984-01-01

    If a malfunction occurs in a solar thermal point-focus distributed receiver power plant while a concentrator is pointed at the sun, motion of the concentrator may stop. As the sun moves relative to the earth, the spot of concentrated sunlight then slowly walks off the receiver aperture, across the receiver face plate, and perhaps across adjacent portions of the concentrator. Intense local heating by the concentrated sunlight may damage or destroy these parts. The behavior of various materials under conditions simulating walk-off of a parabolic dish solar collector were evaluated. Each test consisted of exposure to concentrated sunlight at a peak flux density of about 7000 kW/square meter for 15 minutes. Types of materials tested included graphite, silicon carbide, silica, various silicates, alumina, zirconia, aluminum, copper, steel, and polytetrafluroethylene. The only material that neither cracked nor melted was grade G-90 graphite. Grade CS graphite, a lower cost commercial grade, cracked half-way across, but did not fail apart. Both of these grades are medium-grain extruded graphites. A graphite cloth (graphitized polyacrylonitrile) showed fair performance when tested as a single thin ply; it might be useful as a multi-ply assembly. High purity slipcast silica showed some promise also.

  20. Coda reconstruction from cross-correlation of a diffuse field on thin elastic plates

    Science.gov (United States)

    Hejazi Nooghabi, Aida; Boschi, Lapo; Roux, Philippe; de Rosny, Julien

    2017-09-01

    This study contributes to the evaluation of the robustness and accuracy of Green's function reconstruction from cross-correlation of strongly dispersed reverberated signals, with disentangling of the respective roles of ballistic and reverberated ("coda") contributions. We conduct a suite of experiments on a highly reverberating thin duralumin plate, where an approximately diffuse flexural wave field is generated by taking advantage of the plate reverberation and wave dispersion. A large number of impulsive sources that cover the whole surface of the plate are used to validate ambient-noise theory through comparison of the causal and anticausal (i.e., positive- and negative-time) terms of the cross-correlation to one another and to the directly measured Green's function. To quantify the contribution of the ballistic and coda signals, the cross-correlation integral is defined over different time windows of variable length, and the accuracy of the reconstructed Green's function is studied as a function of the initial and end times of the integral. We show that even cross-correlations measured over limited time windows converge to a significant part of the Green's function. Convergence is achieved over a wide time window, which includes not only direct flexural-wave arrivals, but also the multiply reverberated coda. We propose a model, based on normal-mode analysis, that relates the similarity between the cross-correlation and the Green's function to the statistical properties of the plate. We also determine quantitatively how incoherent noise degrades the estimation of the Green's function.

  1. Practical factors affecting the performance of a thin-film phase plate for transmission electron microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Danev, Radostin [Okazaki Institute for Integrative Bioscience, National Institutes of Natural Sciences, 5-1 Higashiyama, Miyodaiji-cho, Okazaki, Aichi 444-8787 (Japan)], E-mail: rado@nips.ac.jp; Glaeser, Robert M. [Life Sciences Division, 363B Donner Laboratory, Lawrence Berkeley National Laboratory, University of California, Berkeley, CA 94720 (United States); Nagayama, Kuniaki [Okazaki Institute for Integrative Bioscience, National Institutes of Natural Sciences, 5-1 Higashiyama, Miyodaiji-cho, Okazaki, Aichi 444-8787 (Japan)

    2009-03-15

    A number of practical issues must be addressed when using thin carbon films as quarter-wave plates for Zernike phase-contrast electron microscopy. We describe, for example, how we meet the more stringent requirements that must be satisfied for beam alignment in this imaging mode. In addition we address the concern that one might have regarding the loss of some of the scattered electrons as they pass through such a phase plate. We show that two easily measured parameters, (1) the low-resolution image contrast produced in cryo-EM images of tobacco mosaic virus particles and (2) the fall-off of the envelope function at high resolution, can be used to quantitatively compare the data quality for Zernike phase-contrast images and for defocused bright-field images. We describe how we prepare carbon-film phase plates that are initially free of charging or other effects that degrade image quality. We emphasize, however, that even though the buildup of hydrocarbon contamination can be avoided by heating the phase plates during use, their performance nevertheless deteriorates over the time scale of days to weeks, thus requiring their frequent replacement in order to maintain optimal performance.

  2. Dielectric barrier discharge ionization in characterization of organic compounds separated on thin-layer chromatography plates.

    Directory of Open Access Journals (Sweden)

    Michał Cegłowski

    Full Text Available A new method for on-spot detection and characterization of organic compounds resolved on thin layer chromatography (TLC plates has been proposed. This method combines TLC with dielectric barrier discharge ionization (DBDI, which produces stable low-temperature plasma. At first, the compounds were separated on TLC plates and then their mass spectra were directly obtained with no additional sample preparation. To obtain good quality spectra the center of a particular TLC spot was heated from the bottom to increase volatility of the compound. MS/MS analyses were also performed to additionally characterize all analytes. The detection limit of proposed method was estimated to be 100 ng/spot of compound.

  3. Single-electron pulse-height spectra in thin-gap parallel-plate chambers

    CERN Document Server

    Fonte, Paulo J R; Peskov, Vladimir; Policarpo, Armando

    1999-01-01

    Single-electron pulse-height spectra were measured in 0.6 and 1.2 mm parallel-plate chambers developed for the TOF system of the ALICE /LHC-HI experiment. Mixtures of Ar with ethane, isobutane, and SF/sub 6/ were studied. The observed spectrum shows a clear peak for all gases, suggesting efficient single-electron detection in thin parallel-plate structures. The pulse-height spectrum can be described by the weighted sum of an exponential and a Polya distribution, the Polya contribution becoming more important at higher gains. Additionally, it was found that the maximum gain, above 10/sup 6/, is limited by the appearance of streamers and depends weakly on the gas composition. The suitability of each mixture for single-electron detection is also quantitatively assessed. (8 refs).

  4. Error compensation of thin plate-shape part with prebending method in face milling

    Science.gov (United States)

    Yi, Wei; Jiang, Zhaoliang; Shao, Weixian; Han, Xiangcheng; Liu, Wenping

    2015-01-01

    Low weight and good toughness thin plate parts are widely used in modern industry, but its flexibility seriously impacts the machinability. Plenty of studies focus on the influence of machine tool and cutting tool on the machining errors. However, few researches focus on compensating machining errors through the fixture. In order to improve the machining accuracy of thin plate-shape part in face milling, this paper presents a novel method for compensating the surface errors by prebending the workpiece during the milling process. First, a machining error prediction model using finite element method is formulated, which simplifies the contacts between the workpiece and fixture with spring constraints. Milling forces calculated by the micro-unit cutting force model are loaded on the error prediction model to predict the machining error. The error prediction results are substituted into the given formulas to obtain the prebending clamping forces and clamping positions. Consequently, the workpiece is prebent in terms of the calculated clamping forces and positions during the face milling operation to reduce the machining error. Finally, simulation and experimental tests are carried out to validate the correctness and efficiency of the proposed error compensation method. The experimental measured flatness results show that the flatness improves by approximately 30 percent through this error compensation method. The proposed method not only predicts the machining errors in face milling thin plate-shape parts but also reduces the machining errors by taking full advantage of the workpiece prebending caused by fixture, meanwhile, it provides a novel idea and theoretical basis for reducing milling errors and improving the milling accuracy.

  5. Structure and Thermal Stability of Copper Nitride Thin Films

    Directory of Open Access Journals (Sweden)

    Guangan Zhang

    2013-01-01

    Full Text Available Copper nitride (Cu3N thin films were deposited on glass via DC reactive magnetron sputtering at various N2 flow rates and partial pressures with 150°C substrate temperature. X-ray diffraction and scanning electron microscopy were used to characterize the microstructure and morphology. The results show that the films are composed of Cu3N crystallites with anti-ReO3 structure. The microstructure and morphology of the Cu3N film strongly depend on the N2 flow rate and partial pressure. The cross-sectional micrograph of the film shows typical columnar, compact structure. The thermal stabilities of the films were investigated using vacuum annealing under different temperature. The results show that the introducing of argon in the sputtering process decreases the thermal stability of the films.

  6. Thin-Film Phase Plates for Transmission Electron Microscopy Fabricated from Metallic Glasses.

    Science.gov (United States)

    Dries, Manuel; Hettler, Simon; Schulze, Tina; Send, Winfried; Müller, Erich; Schneider, Reinhard; Gerthsen, Dagmar; Luo, Yuansu; Samwer, Konrad

    2016-10-01

    Thin-film phase plates (PPs) have become an interesting tool to enhance the contrast of weak-phase objects in transmission electron microscopy (TEM). The thin film usually consists of amorphous carbon, which suffers from quick degeneration under the intense electron-beam illumination. Recent investigations have focused on the search for alternative materials with an improved material stability. This work presents thin-film PPs fabricated from metallic glass alloys, which are characterized by a high electrical conductivity and an amorphous structure. Thin films of the zirconium-based alloy Zr65.0Al7.5Cu27.5 (ZAC) were fabricated and their phase-shifting properties were evaluated. The ZAC film was investigated by different TEM techniques, which reveal beneficial properties compared with amorphous carbon PPs. Particularly favorable is the small probability for inelastic plasmon scattering, which results from the combined effect of a moderate inelastic mean free path and a reduced film thickness due to a high mean inner potential. Small probability plasmon scattering improves contrast transfer at high spatial frequencies, which makes the ZAC alloy a promising material for PP fabrication.

  7. Thermal conductivity of yttria-stabilized zirconia thin films with a zigzag microstructure

    Science.gov (United States)

    Amaya, C.; Prías-Barragán, J. J.; Aperador, W.; Hernández-Landaverde, M. A.; Ramírez-Cardona, M.; Caicedo, J. C.; Rodríguez, L. A.; Snoeck, E.; Gómez, M. E.; Zambrano, G.

    2017-06-01

    Yttria-stabilized zirconia (YSZ) is the most common material used as a thermal barrier in several engineering applications. In order to improve the insulator potential of these thin films, an oblique-angle deposition approach was used to grow YSZ with tilted columnar structures. Initially, the period (n) was defined as the repetition unit composed of two layers each with different columnar growth directions, and then, n was increased (n = 1, 2, 10, 30, and 50), keeping constant the total thickness (˜3.50 μm). The influence of (n) on the structure, roughness, grain size, microstructure, and thermal conductivity (κ) of thin films deposited was determined by X-ray diffraction (XRD), atomic force microscopy (AFM), scanning electron microscopy (SEM), transmission electron microscopy, and hot-plate technique, respectively. For all the samples, XRD patterns indicate the presence of the characteristic 8YSZ tetragonal phase peaks. Through AFM analysis, it was established that the roughness of the films deposited decreases from (4.0 ± 0.6) to (2.0 ± 0.6) nm when n is increased. Cross-sectional images recorded by SEM corroborate the formation of marked interfaces when growth direction changes occur, allowing to identify a multilayer system with a "zigzag" microstructure and an evolution towards more refined and isolated columns. Moreover, the SEM images reveal that for n = 10, 30, 50, and 70, the growth direction of the column is perpendicular to the substrate plane, losing its tilted form and the "zigzag" behavior becomes intra-columnar, reaching nanometer scale. Finally, analyses by hot-plate technique for different n repetition units showed that the thermal conductivity of YSZ films decreases from 0.151 W/m K to 0.064 W/m K, establishing the direct influence of the "zigzag" microstructure on the κ value. This study shows the potential of growing YSZ thin films by oblique-angle deposition as an effective method to improving the thermal insulator potential of this

  8. Convection induced by thermal gradients on thin reaction fronts

    Science.gov (United States)

    Ruelas Paredes, David R. A.; Vasquez, Desiderio A.

    2017-09-01

    We present a thin front model for the propagation of chemical reaction fronts in liquids inside a Hele-Shaw cell or porous media. In this model we take into account density gradients due to thermal and compositional changes across a thin interface. The front separating reacted from unreacted fluids evolves following an eikonal relation between the normal speed and the curvature. We carry out a linear stability analysis of convectionless flat fronts confined in a two-dimensional rectangular domain. We find that all fronts are stable to perturbations of short wavelength, but they become unstable for some wavelengths depending on the values of compositional and thermal gradients. If the effects of these gradients oppose each other, we observe a range of wavelengths that make the flat front unstable. Numerical solutions of the nonlinear model show curved fronts of steady shape with convection propagating faster than flat fronts. Exothermic fronts increase the temperature of the fluid as they propagate through the domain. This increment in temperature decreases with increasing speed.

  9. Thermal flexural analysis of cross-ply laminated plates using trigonometric shear deformation theory

    Directory of Open Access Journals (Sweden)

    Yuwaraj Marotrao Ghugal

    Full Text Available Thermal stresses and displacements for orthotropic, two-layer antisymmetric, and three-layer symmetric square cross-ply laminated plates subjected to nonlinear thermal load through the thickness of laminated plates are presented by using trigonometric shear deformation theory. The in-plane displacement field uses sinusoidal function in terms of thickness co-ordinate to include the shear deformation effect. The theory satisfies the shear stress free boundary conditions on the top and bottom surfaces of the plate. The present theory obviates the need of shear correction factor. Governing equations and boundary conditions of the theory are obtained using the principle of virtual work. The validity of present theory is verified by comparing the results with those of classical plate theory and first order shear deformation theory and higher order shear deformation theory.

  10. Generation mechanism of nonlinear ultrasonic Lamb waves in thin plates with randomly distributed micro-cracks.

    Science.gov (United States)

    Zhao, Youxuan; Li, Feilong; Cao, Peng; Liu, Yaolu; Zhang, Jianyu; Fu, Shaoyun; Zhang, Jun; Hu, Ning

    2017-08-01

    Since the identification of micro-cracks in engineering materials is very valuable in understanding the initial and slight changes in mechanical properties of materials under complex working environments, numerical simulations on the propagation of the low frequency S 0 Lamb wave in thin plates with randomly distributed micro-cracks were performed to study the behavior of nonlinear Lamb waves. The results showed that while the influence of the randomly distributed micro-cracks on the phase velocity of the low frequency S 0 fundamental waves could be neglected, significant ultrasonic nonlinear effects caused by the randomly distributed micro-cracks was discovered, which mainly presented as a second harmonic generation. By using a Monte Carlo simulation method, we found that the acoustic nonlinear parameter increased linearly with the micro-crack density and the size of micro-crack zone, and it was also related to the excitation frequency and friction coefficient of the micro-crack surfaces. In addition, it was found that the nonlinear effect of waves reflected by the micro-cracks was more noticeable than that of the transmitted waves. This study theoretically reveals that the low frequency S 0 mode of Lamb waves can be used as the fundamental waves to quantitatively identify micro-cracks in thin plates. Copyright © 2017 Elsevier B.V. All rights reserved.

  11. Quantification of the spatial strain distribution of scoliosis using a thin-plate spline method.

    Science.gov (United States)

    Kiriyama, Yoshimori; Watanabe, Kota; Matsumoto, Morio; Toyama, Yoshiaki; Nagura, Takeo

    2014-01-03

    The objective of this study was to quantify the three-dimensional spatial strain distribution of a scoliotic spine by nonhomogeneous transformation without using a statistically averaged reference spine. The shape of the scoliotic spine was determined from computed tomography images from a female patient with adolescent idiopathic scoliosis. The shape of the scoliotic spine was enclosed in a rectangular grid, and symmetrized using a thin-plate spline method according to the node positions of the grid. The node positions of the grid were determined by numerical optimization to satisfy symmetry. The obtained symmetric spinal shape was enclosed within a new rectangular grid and distorted back to the original scoliotic shape using a thin-plate spline method. The distorted grid was compared to the rectangular grid that surrounded the symmetrical spine. Cobb's angle was reduced from 35° in the scoliotic spine to 7° in the symmetrized spine, and the scoliotic shape was almost fully symmetrized. The scoliotic spine showed a complex Green-Lagrange strain distribution in three dimensions. The vertical and transverse compressive/tensile strains in the frontal plane were consistent with the major scoliotic deformation. The compressive, tensile and shear strains on the convex side of the apical vertebra were opposite to those on the concave side. These results indicate that the proposed method can be used to quantify the three-dimensional spatial strain distribution of a scoliotic spine, and may be useful in quantifying the deformity of scoliosis. © 2013 Elsevier Ltd. All rights reserved.

  12. RGB color calibration for quantitative image analysis: the "3D thin-plate spline" warping approach.

    Science.gov (United States)

    Menesatti, Paolo; Angelini, Claudio; Pallottino, Federico; Antonucci, Francesca; Aguzzi, Jacopo; Costa, Corrado

    2012-01-01

    In the last years the need to numerically define color by its coordinates in n-dimensional space has increased strongly. Colorimetric calibration is fundamental in food processing and other biological disciplines to quantitatively compare samples' color during workflow with many devices. Several software programmes are available to perform standardized colorimetric procedures, but they are often too imprecise for scientific purposes. In this study, we applied the Thin-Plate Spline interpolation algorithm to calibrate colours in sRGB space (the corresponding Matlab code is reported in the Appendix). This was compared with other two approaches. The first is based on a commercial calibration system (ProfileMaker) and the second on a Partial Least Square analysis. Moreover, to explore device variability and resolution two different cameras were adopted and for each sensor, three consecutive pictures were acquired under four different light conditions. According to our results, the Thin-Plate Spline approach reported a very high efficiency of calibration allowing the possibility to create a revolution in the in-field applicative context of colour quantification not only in food sciences, but also in other biological disciplines. These results are of great importance for scientific color evaluation when lighting conditions are not controlled. Moreover, it allows the use of low cost instruments while still returning scientifically sound quantitative data.

  13. 3D craniofacial registration using thin-plate spline transform and cylindrical surface projection.

    Science.gov (United States)

    Chen, Yucong; Zhao, Junli; Deng, Qingqiong; Duan, Fuqing

    2017-01-01

    Craniofacial registration is used to establish the point-to-point correspondence in a unified coordinate system among human craniofacial models. It is the foundation of craniofacial reconstruction and other craniofacial statistical analysis research. In this paper, a non-rigid 3D craniofacial registration method using thin-plate spline transform and cylindrical surface projection is proposed. First, the gradient descent optimization is utilized to improve a cylindrical surface fitting (CSF) for the reference craniofacial model. Second, the thin-plate spline transform (TPST) is applied to deform a target craniofacial model to the reference model. Finally, the cylindrical surface projection (CSP) is used to derive the point correspondence between the reference and deformed target models. To accelerate the procedure, the iterative closest point ICP algorithm is used to obtain a rough correspondence, which can provide a possible intersection area of the CSP. Finally, the inverse TPST is used to map the obtained corresponding points from the deformed target craniofacial model to the original model, and it can be realized directly by the correspondence between the original target model and the deformed target model. Three types of registration, namely, reflexive, involutive and transitive registration, are carried out to verify the effectiveness of the proposed craniofacial registration algorithm. Comparison with the methods in the literature shows that the proposed method is more accurate.

  14. Instabilities of convection patterns in a shear-thinning fluid between plates of finite conductivity

    Science.gov (United States)

    Varé, Thomas; Nouar, Chérif; Métivier, Christel

    2017-10-01

    Rayleigh-Bénard convection in a horizontal layer of a non-Newtonian fluid between slabs of arbitrary thickness and finite thermal conductivity is considered. The first part of the paper deals with the primary bifurcation and the relative stability of convective patterns at threshold. Weakly nonlinear analysis combined with Stuart-Landau equation is used. The competition between squares and rolls, as a function of the shear-thinning degree of the fluid, the slabs' thickness, and the ratio of the thermal conductivity of the slabs to that of the fluid is investigated. Computations of heat transfer coefficients are in agreement with the maximum heat transfer principle. The second part of the paper concerns the stability of the convective patterns toward spatial perturbations and the determination of the band width of the stable wave number in the neighborhood of the critical Rayleigh number. The approach used is based on the Ginzburg-Landau equations. The study of rolls stability shows that: (i) for low shear-thinning effects, the band of stable wave numbers is bounded by zigzag instability and cross-roll instability. Furthermore, the marginal cross-roll stability boundary enlarges with increasing shear-thinning properties; (ii) for high shear-thinning effects, Eckhaus instability becomes more dangerous than cross-roll instability. For square patterns, the wave number selection is always restricted by zigzag instability and by "rectangular Eckhaus" instability. In addition, the width of the stable wave number decreases with increasing shear-thinning effects. Numerical simulations of the planform evolution are also presented to illustrate the different instabilities considered in the paper.

  15. Diapir versus along-channel ascent of crustal material during plate convergence: Constrained by the thermal structure of subduction zones

    Science.gov (United States)

    Liu, Ming-Qi; Li, Zhong-Hai; Yang, Shao-Hua

    2017-09-01

    Subduction channel processes are crucial for understanding the material and energy exchange between the Earth's crust and mantle. Crustal rocks can be subducted to mantle depths, interact with the mantle wedge, and then exhume to the crustal depth again, which is generally considered as the mechanism for the formation of ultrahigh-pressure metamorphic rocks in nature. In addition, the crustal rocks generally undergo dehydration and melting at subarc depths, giving rise to fluids that metasomatize and weaken the overlying mantle wedge. There are generally two ways for the material ascent from subarc depths: one is along subduction channels; the other is through the mantle wedge by diapir. In order to study the conditions and dynamics of these contrasting material ascent modes, systematic petrological-thermo-mechanical numerical models are constructed with variable thicknesses of the overriding and subducting continental plates, ages of the subducting oceanic plate, as well as the plate convergence rates. The model results suggest that the thermal structures of subduction zones control the thermal condition and fluid/melt activity at the slab-mantle interface in subcontinental subduction channels, which further strongly affect the material transportation and ascent mode. The thick overriding continental plate and the low-angle subduction style induced by young subducting oceanic plate both contribute to the formation of relatively cold subduction channels with strong overriding mantle wedge, where the along-channel exhumation occurs exclusively to result in the exhumation of HP-UHP metamorphic rocks. In contrast, the thin overriding lithosphere and the steep subduction style induced by old subducting oceanic plate are the favorable conditions for hot subduction channels, which lead to significant hydration and metasomatism, melting and weakening of the overriding mantle wedge and thus cause the ascent of mantle wedge-derived melts by diapir through the mantle wedge

  16. Thermal stability analysis of eccentrically stiffened Sigmoid-FGM plate with metal–ceramic–metal layers based on FSDT

    Directory of Open Access Journals (Sweden)

    Pham Hong Cong

    2016-12-01

    Full Text Available This paper researches the thermal stability of eccentrically stiffened plates made of functionally graded materials (FGM with metal–ceramic–metal layers subjected to thermal load. The equilibrium and compatibility equations for the plates are derived by using the first-order shear deformation theory of plates, taking into account both the geometrical nonlinearity in the von Karman sense and initial geometrical imperfections with Pasternak type elastic foundations. By applying Galerkin method and using stress function, effects of material and geometrical properties, elastic foundations, temperature-dependent material properties, and stiffeners on the thermal stability of the eccentrically stiffened S-FGM plates in thermal environment are analyzed and discussed.

  17. Fuel cell end plate structure

    Science.gov (United States)

    Guthrie, Robin J.; Katz, Murray; Schroll, Craig R.

    1991-04-23

    The end plates (16) of a fuel cell stack (12) are formed of a thin membrane. Pressure plates (20) exert compressive load through insulation layers (22, 26) to the membrane. Electrical contact between the end plates (16) and electrodes (50, 58) is maintained without deleterious making and breaking of electrical contacts during thermal transients. The thin end plate (16) under compressive load will not distort with a temperature difference across its thickness. Pressure plate (20) experiences a low thermal transient because it is insulated from the cell. The impact on the end plate of any slight deflection created in the pressure plate by temperature difference is minimized by the resilient pressure pad, in the form of insulation, therebetween.

  18. Thin Thermal-Insulation Blankets for Very High Temperatures

    Science.gov (United States)

    Choi, Michael K.

    2003-01-01

    Thermal-insulation blankets of a proposed type would be exceptionally thin and would endure temperatures up to 2,100 C. These blankets were originally intended to protect components of the NASA Solar Probe spacecraft against radiant heating at its planned closest approach to the Sun (a distance of 4 solar radii). These blankets could also be used on Earth to provide thermal protection in special applications (especially in vacuum chambers) for which conventional thermal-insulation blankets would be too thick or would not perform adequately. A blanket according to the proposal (see figure) would be made of molybdenum, titanium nitride, and carbon- carbon composite mesh, which melt at temperatures of 2,610, 2,930, and 2,130 C, respectively. The emittance of molybdenum is 0.24, while that of titanium nitride is 0.03. Carbon-carbon composite mesh is a thermal insulator. Typically, the blanket would include 0.25-mil (.0.00635-mm)-thick hot-side and cold-side cover layers of molybdenum. Titanium nitride would be vapor-deposited on both surfaces of each cover layer. Between the cover layers there would be 10 inner layers of 0.15-mil (.0.0038-mm)-thick molybdenum with vapor-deposited titanium nitride on both sides of each layer. The thickness of each titanium nitride coat would be about 1,000 A. The cover and inner layers would be interspersed with 0.25-mil (0.00635-mm)-thick layers of carbon-carbon composite mesh. The blanket would have total thickness of 4.75 mils (approximately equal to 0.121 mm) and an areal mass density of 0.7 kilograms per square meter. One could, of course, increase the thermal- insulation capability of the blanket by increasing number of inner layers (thereby unavoidably increasing the total thickness and mass density).

  19. Guided-wave technique for the measurement of dielectric thin-film materials' thermal properties.

    Science.gov (United States)

    Huguet-Chantĵme, Pascal; Escoubas, Ludovic; Flory, François

    2002-06-01

    A pump-and-probe setup that uses a totally reflecting prism coupler is presented. Its electromagnetic and thermal models are described. To our knowledge, the first results are given concerning the measurement of thermal properties of thin films.

  20. Laser irradiation effects on thin aluminum plates subjected to surface flow

    Science.gov (United States)

    Jiang, Houman; Zhao, Guomin; Chen, Minsun; Peng, Xin

    2016-10-01

    The irradiation effects of LD laser on thin aluminum alloy plates are studied in experiments characterized by relatively large laser spot and the presence of 0.3Ma surface airflow. A high speed profilometer is used to record the profile change along a vertical line in the rear surface of the target, and the history of the displacement along the direction of thickness of the central point at the rear surface is obtained. The results are compared with those without airflow and those by C. D. Boley. We think that it is the temperature rise difference along the direction of thickness instead of the pressure difference caused by the airflow that makes the thin target bulge into the incoming beam, no matter whether the airflow is blown or not, and that only when the thin aluminum target is heated thus softened enough by the laser irradiation, can the aerodynamic force by the surface airflow cause non-ignorable localized plastic deformation and result a burn-through without melting in the target. However, though the target isn't softened enough in terms of the pressure difference, it might have experienced notable deformation as it is heated from room temperature to several hundred degree centigrade.

  1. Thermal Hydraulic Characteristics of Fuel Defects in Plate Type Nuclear Research Reactors

    Energy Technology Data Exchange (ETDEWEB)

    Bodey, Isaac T [ORNL

    2014-05-01

    Turbulent flow coupled with heat transfer is investigated for a High Flux Isotope Reactor (HFIR) fuel plate. The Reynolds Averaged Navier-Stokes Models are used for fluid dynamics and the transfer of heat from a thermal nuclear fuel plate using the Multi-physics code COMSOL. Simulation outcomes are compared with experimental data from the Advanced Neutron Source Reactor Thermal Hydraulic Test Loop. The computational results for the High Flux Isotope Reactor core system provide a more physically accurate simulation of this system by modeling the turbulent flow field in conjunction with the diffusion of thermal energy within the solid and fluid phases of the model domain. Recommendations are made regarding Nusselt number correlations and material properties for future thermal hydraulic modeling efforts

  2. High efficiency event-counting thermal neutron imaging using Gd doped micro channel plate

    OpenAIRE

    Tian, Yang; Yang, Yigang; Pan, Jingsheng; Li, Yulan; Li, Yuanjing

    2013-01-01

    An event-counting thermal neutron imaging detector based on 3 mol % natGd2O3 doped micro channel plate (MCP) has been developed and tested. Thermal neutron imaging experiment was carried out with a low flux neutron beam. Detection efficiency of 33 % was achieved with only one doped MCP. The spatial resolution of 72 {\\mu}m RMS is currently limited by the readout anode. A detector with larger area and improved readout method is now being developed.

  3. Small-Scale Flat Plate Collectors for Solar Thermal Scavenging in Low Conductivity Environments

    Directory of Open Access Journals (Sweden)

    Emmanuel Ogbonnaya

    2017-01-01

    Full Text Available There is great opportunity to develop power supplies for autonomous application on the small scale. For example, remote environmental sensors may be powered through the harvesting of ambient thermal energy and heating of a thermoelectric generator. This work investigates a small-scale (centimeters solar thermal collector designed for this application. The absorber is coated with a unique selective coating and then studied in a low pressure environment to increase performance. A numerical model that is used to predict the performance of the collector plate is developed. This is validated based on benchtop testing of a fabricated collector plate in a low-pressure enclosure. Model results indicate that simulated solar input of about 800 W/m2 results in a collector plate temperature of 298 K in ambient conditions and up to 388 K in vacuum. The model also predicts the various losses in W/m2 K from the plate to the surroundings. Plate temperature is validated through the experimental work showing that the model is useful to the future design of these small-scale solar thermal energy collectors.

  4. Investigating the thermal environment effects on geometrically nonlinear vibration of smart functionally graded plates

    Energy Technology Data Exchange (ETDEWEB)

    Ebrahimi, Farzad; Rastgoo, Abbas; Bahrami, Mansoor Nikkhah [University of Tehran, Tehran (Iran, Islamic Republic of)

    2010-03-15

    An analytical solution for a sandwich circular FGM plate coupled with piezoelectric layers under one-dimensional heat conduction is presented. All materials of the device may be of any functional gradients in the direction of thickness. The solution exactly satisfies all the equilibrium conditions and continuity conditions for the stress, displacement and electric displacement as well as electric potential on the interfaces between adjacency layers. A nonlinear static problem is solved first to determine the initial stress state and pre-vibration deformations of the FG plate that is subjected to in-plane forces and applied actuator voltage in thermal environment in the case of simply supported boundary conditions. By adding an incremental dynamic state to the pre-vibration state, the differential equations that govern the nonlinear vibration behavior of pre-stressed piezoelectric coupled FGM plates are derived. The role of thermal environment as well as control effects on nonlinear static deflections and natural frequencies imposed by the piezoelectric actuators using high input voltages are investigated. Numerical examples are provided and simulation results are discussed. Numerical results for FGM plates with a mixture of metal and ceramic are presented in dimensionless forms. The good agreement between the results of this paper and those of the finite element (FE) analyses validated the presented approach. In a parametric study the emphasis is placed on investigating the effect of varying the applied actuator voltage and thermal environment as well as gradient index of FG plate on the dynamics and control characteristics of the structure

  5. Electrochemical study of the thermal treatment effects on Cusub(x)S thin films

    Energy Technology Data Exchange (ETDEWEB)

    Duo, R.; Fatas, E.; Arjona, F.; Camarero, E.G.

    1983-03-01

    The effects of thermal treatments on the stoichiometry and photovoltaic properties of Cusub(x)S thin films have been studied. It has been observed that the evaporation of a thin copper films on Cusub(x)S, followed by thermal treatment in vacuum, improves the Cusub(x)S/CdS heterojunctions due to a rire in the stoichiometry and fill factor.

  6. Thermal simulation of surface micromachined polysilicon hot plates of low power consumption

    NARCIS (Netherlands)

    Dumitrescu, Marius; Cobianu, Cornel; Lungu, Dan; Pascu, Adrian; Kolev, Spas; van den Berg, Albert

    1999-01-01

    A simple, IC compatible, surface micromachined polysilicon membrane was technologically designed and thermally simulated by 3D finite element ‘COSMOS' program in order to investigate its capability to work as a micro hot plate for a gas sensing test structure of low power consumption. For an

  7. Electrochemistry of thin-plate lead-carbon batteries employing alternative current collectors

    Science.gov (United States)

    Lannelongue, Jérémy; Cugnet, Mikael; Guillet, Nicolas; Kirchev, Angel

    2017-06-01

    The article discusses the electrochemistry of lead-carbon battery cells based on thin-plate electrodes with alternative current collectors. The latter are comprised of lead-electroplated graphite foil and expanded titanium mesh coated with SnO2 replacing the conventional negative and positive grids. The results from charge/discharge tests, cycling voltammetry and impedance spectroscopy measurements show that the negative electrodes store energy via three types of electrochemical processes: electrostatic storage, reversible hydrogen storage and precipitation/dissolution of lead and lead sulfate. When the activated carbon is the predominant component of the negative active material the preferred energy storage mechanism is the reversible hydrogen storage. The use of titanium as alternative current collector allows to increase the active material to current collector ratio to 5: 1, retaining a high power performance and increasing the battery lifetime beyond 3000 equivalent cycles in partial state of charge cycling applications.

  8. Influence of Basalt FRP Mesh Reinforcement on High-Performance Concrete Thin Plates at High Temperatures

    DEFF Research Database (Denmark)

    Hulin, Thomas; Lauridsen, Dan H.; Hodicky, Kamil

    2015-01-01

    A basalt fiber–reinforced polymer (BFRP) mesh was introduced as reinforcement in high-performance concrete (HPC) thin plates (20–30 mm) for implementation in precast sandwich panels. An experimental program studied the BFRP mesh influence on HPC exposed to high temperature. A set of standard....... Stereomicroscope observations before and after fire testing focused on the interface between HPC and BFRP mesh and its change with temperature exposure. BFRP mesh showed tendency to reduce the probability of HPC spalling without solving this issue. BFRP mesh alone leads to mechanical failure of concrete elements......, requiring the use of steel. Microscope observations highlighted degradation of the HPC-BFRP mesh interface with temperature due to the melting polymer matrix of the mesh. These observations call for caution when using fiber-reinforced polymer (FRP) reinforcement in elements exposed to fire hazard....

  9. Quality Factor and Microslipping of Fatigue Cracks in Thin Plates at Resonant Vibration

    Science.gov (United States)

    Wincheski, B.; Namkung, M.; Fulton, J. P.

    1993-01-01

    Resonant vibrations have been stimulated in thin metal plates using a non-contacting electromagnetic driver. A sinusoidal force was applied in a swept frequency fashion and the resulting surface displacements were monitored through the use of an acoustic microphone. It has been found that the presence of a fatigue crack in the sample causes a broadening of the second resonance peak. The Q factors of the resonance curves were determined and are directly correlated with the presence of fatigue cracks in the samples. The broadening of the curves is explained in terms of a microslipping at the crack face walls which reduces the amplitude of the resonant vibration by increasing the damping of the system. A comparison is made between the resonance characteristics of fatigue damaged and notched samples, where the stiffness of the two systems is nearly constant while the interaction between crack face walls is eliminated in the latter.

  10. Flat-plate boiloff calorimeters for testing of thermal insulation systems

    Science.gov (United States)

    Fesmire, J. E.; Johnson, W. L.; Kelly, A. O.; Meneghelli, B. J.; Swanger, A. M.

    2015-12-01

    Cryostats have been developed and standardized for laboratory testing of thermal insulation systems in a flat-plate configuration. Boiloff calorimetry is the measurement principle for determining the effective thermal conductivity (ke) and heat flux (q) of test specimens under a wide range of actual conditions. Cryostat-500 is thermally guarded to measure absolute thermal performance when calibrated with a known reference via an adjustable-edge guard ring. With liquid nitrogen as the energy meter, the cold boundary temperature can be adjusted to any temperature between 77 K and approximately 300 K by the interposition of a thermal resistance layer between the cold mass and the specimen. A low thermal conductivity suspension system has compliance rods that adjust for specimen thickness and compression force. Material type, thickness, density, flatness, compliance, outgassing, and temperature sensor placement are important test considerations, and edge effects and calibration techniques for the apparatus are crucial. Over the full vacuum pressure range, the thermal performance capability is nearly four orders of magnitude. The horizontal configuration provides key advantages over the vertical cylindrical cryostats for testing at ambient pressure conditions. Cryostat-500’s design and test methods, other flat-plate boiloff calorimeters, and results for select thermal insulation materials (composites, foams, aerogels) are discussed.

  11. Thermal characterization of flat-plate photovoltaic arrays

    Science.gov (United States)

    Fuentes, M. K.

    The net effect of an array's operating cell temperature on energy output can be characterized by a single effective cell temperature (ECT). ECT is that temperature at which an array would operate were it to operate at a constant cell temperature and produce the same energy as it would in the natural environment. Since an array effectively produces all of its energy at ECT, an operating efficiency at ECT is also the overall efficiency of the array. A methodology for estimating ECT from the Nominal Operating Cell Temperature (NOCT)is presented. Also presented is new thermal model. The model has been incorporated into the photovoltaic (PV) performance model, PVFORM, and has been proven to be accurate to within 5 C.

  12. A new analytical model for the low-velocity perforation of thin steel plates by hemispherical-nosed projectiles

    Directory of Open Access Journals (Sweden)

    Chang-hai Chen

    2017-10-01

    Full Text Available Ballistic experiments were conducted on thin steel plates that are normally impacted by hemispherical-nosed projectiles at velocities higher than their ballistic limits. The deformation and failure modes of the thin steel plates were analyzed. A new method was proposed according to the experimental results and the perforation phenomenon of the thin steel plates to determine the radius of the bulging region. In establishing this new method, a dynamic method combined with the plastic wave propagation concept based on the rigid plastic assumption was adopted. The whole perforation process was divided into four consecutive stages, namely, bulging deformation, dishing deformation, ductile hole enlargement, and projectile exit. On the basis of the energy conservation principle, a new model was developed to predict the residual velocities of hemispherical-nosed projectiles that perforate thin steel plates at low velocities. The results obtained from the theoretical calculations by the present model were compared with the experimental results. Theoretical predictions were in good agreement with the experimental results in terms of both the radius of the bulging region and the residual velocity of the projectile when the strain rate effects of the target material during each stage were considered.

  13. Experimental studies on the deformation and rupture of thin metal plates subject to underwater shock wave loading

    Directory of Open Access Journals (Sweden)

    Chen Pengwan

    2015-01-01

    Full Text Available In this paper, the dynamic deformation and rupture of thin metal plates subject to underwater shock wave loading are studied by using high-speed 3D digital image correlation (3D-DIC. An equivalent device consist of a gas gun and a water anvil tube was used to supplying an exponentially decaying pressure in lieu of explosive detonation which acted on the panel specimen. The thin metal plate is clamped on the end of the shock tube by a flange. The deformation and rupture process of the metal plates subject to underwater shock waves are recorded by two high-speed cameras. The shape, displacement fields and strain fields of the metal plates under dynamic loading are obtained by using VIC-3D digital image correlation software. The strain gauges also were used to monitor the structural response on the selected position for comparison. The DIC data and the strain gauges results show a high level of correlation, and 3D-DIC is proven to be an effective method to measure 3D full-field dynamic response of structures under underwater impact loading. The effects of pre-notches on the failure modes of thin circular plate were also discussed.

  14. Tectonic plates, D (double prime) thermal structure, and the nature of mantle plumes

    Science.gov (United States)

    Lenardic, A.; Kaula, W. M.

    1994-01-01

    It is proposed that subducting tectonic plates can affect the nature of thermal mantle plumes by determining the temperature drop across a plume source layer. The temperature drop affects source layer stability and the morphology of plumes emitted from it. Numerical models are presented to demonstrate how introduction of platelike behavior in a convecting temperature dependent medium, driven by a combination of internal and basal heating, can increase the temperature drop across the lower boundary layer. The temperature drop increases dramatically following introduction of platelike behavior due to formation of a cold temperature inversion above the lower boundary layer. This thermal inversion, induced by deposition of upper boundary layer material to the system base, decays in time, but the temperature drop across the lower boundary layer always remains considerably higher than in models lacking platelike behavior. On the basis of model-inferred boundary layer temperature drops and previous studies of plume dynamics, we argue that generally accepted notions as to the nature of mantle plumes on Earth may hinge on the presence of plates. The implication for Mars and Venus, planets apparently lacking plate tectonics, is that mantle plumes of these planets may differ morphologically from those of Earth. A corollary model-based argument is that as a result of slab-induced thermal inversions above the core mantle boundary the lower most mantle may be subadiabatic, on average (in space and time), if major plate reorganization timescales are less than those acquired to diffuse newly deposited slab material.

  15. Thermal Effects on Vibration and Control of Piezocomposite Kirchhoff Plate Modeled by Finite Elements Method

    Directory of Open Access Journals (Sweden)

    M. Sanbi

    2015-01-01

    Full Text Available Theoretical and numerical results of the modeling of a smart plate are presented for optimal active vibration control. The smart plate consists of a rectangular aluminum piezocomposite plate modeled in cantilever configuration with surface bonded thermopiezoelectric patches. The patches are symmetrically bonded on top and bottom surfaces. A generic thermopiezoelastic theory for piezocomposite plate is derived, using linear thermopiezoelastic theory and Kirchhoff assumptions. Finite element equations for the thermopiezoelastic medium are obtained by using the linear constitutive equations in Hamilton’s principle together with the finite element approximations. The structure is modelled analytically and then numerically and the results of simulations are presented in order to visualize the states of their dynamics and the state of control. The optimal control LQG-Kalman filter is applied. By using this model, the study first gives the influences of the actuator/sensor pair placement and size on the response of the smart plate. Second, the effects of thermoelastic and pyroelectric couplings on the dynamics of the structure and on the control procedure are studied and discussed. It is shown that the effectiveness of the control is not affected by the applied thermal gradient and can be applied with or without this gradient at any time of plate vibrations.

  16. Thermal transport between a continuously moving heated plate and a quiescent ambient medium

    Science.gov (United States)

    Karwe, Mukund Vishnu

    A numerical and experimental investigation of the heat transfer and the fluid flow associated with a continuously moving flat surface was carried out. This circumstance is encountered in manufacturing processes such as hot rolling, extrusion, and continuous casting. The resulting temperature distribution within the solid, the appropriate conditions that arise at the location where the plate emerges from the furnace of the die, and the nature of the induced flow field and the heat transfer rate, are of interest. These considerations are important in the simulation, design, control, and optimization of the practical systems. In the numerical part of the study, the thermal transport from a flat, infinitely wide, continuously moving plate, was studied assuming a two-dimensional steady circumstance. The boundary layer equations as well as full governing equations, including buoyancy effects, were solved employing finite difference techniques. Conjugate transport, involving conduction within the plate, radiative loss from the plates surface and convection to the fluid, was considered. The temperature measurements were carried out for a heated aluminum plate moving vertically downward in water and moving upward or downward in the air. The temperature distributions, within the moving plate and the induced flow, were measured, using a microcomputer-controlled data acquisition system. The flow was visualized by means of a shadowgraph.

  17. Analytical Model of Cyclic Heat Exchange of the Plate of Finite Sizes Adjusted for the Thermal Relaxation

    Science.gov (United States)

    Kirsanov, Yu A.; Makarushkin, D. V.; Yudakhin, A. E.; Kirsanov, A. Yu

    2017-11-01

    The hyperbolic boundary value problem of heat conduction in a two-dimensional rectangular plate with the third kind boundary conditions was formulated. The model of transient thermal processes in the body takes into account changes in time and along the flow direction of the ambient temperature. An analytical solution was obtained for the temperature field in the plate, adjusted for the phenomena of thermal relaxation and thermal damping.

  18. Thin graphite bipolar plate with associated gaskets and carbon cloth flow-field for use in an ionomer membrane fuel cell

    Science.gov (United States)

    Marchetti, George A.

    2003-01-03

    The present invention comprises a thin graphite plate with associated gaskets and pieces of carbon cloth that comprise a flow-field. The plate, gaskets and flow-field comprise a "plate and gasket assembly" for use in an ionomer membrane fuel cell, fuel cell stack or battery.

  19. Ductile Tearing of Thin Aluminum Plates Under Blast Loading. Predictions with Fully Coupled Models and Biaxial Material Response Characterization

    Energy Technology Data Exchange (ETDEWEB)

    Corona, Edmundo [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Gullerud, Arne S. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Haulenbeek, Kimberly K. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Reu, Phillip L. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2015-06-01

    The work presented in this report concerns the response and failure of thin 2024- T3 aluminum alloy circular plates to a blast load produced by the detonation of a nearby spherical charge. The plates were fully clamped around the circumference and the explosive charge was located centrally with respect to the plate. The principal objective was to conduct a numerical model validation study by comparing the results of predictions to experimental measurements of plate deformation and failure for charges with masses in the vicinity of the threshold between no tearing and tearing of the plates. Stereo digital image correlation data was acquired for all tests to measure the deflection and strains in the plates. The size of the virtual strain gage in the measurements, however, was relatively large, so the strain measurements have to be interpreted accordingly as lower bounds of the actual strains in the plate and of the severity of the strain gradients. A fully coupled interaction model between the blast and the deflection of the structure was considered. The results of the validation exercise indicated that the model predicted the deflection of the plates reasonably accurately as well as the distribution of strain on the plate. The estimation of the threshold charge based on a critical value of equivalent plastic strain measured in a bulge test, however, was not accurate. This in spite of efforts to determine the failure strain of the aluminum sheet under biaxial stress conditions. Further work is needed to be able to predict plate tearing with some degree of confidence. Given the current technology, at least one test under the actual blast conditions where the plate tears is needed to calibrate the value of equivalent plastic strain when failure occurs in the numerical model. Once that has been determined, the question of the explosive mass value at the threshold could be addressed with more confidence.

  20. Comparison of full 3-D, thin-film 3-D, and thin-film plate analyses of a postbuckled embedded delamination

    Science.gov (United States)

    Whitcomb, John D.

    1989-01-01

    Local buckling can cause large interlaminar stresses along the delamination front, which can lead to delamination growth. This paper examines several methods of calculating strain-energy release rates, which are often used to predict delamination growth. The thin-film plate analysis, which was least expensive, calculated the total strain-energy release rate G(T) quite accurately. However, the stress field along the delamination front is highly mixed-mode and has no fixed ratio of G(I) to G(II). Since plate analysis can only calculate G(T), it would not be useful for accurate predictions of delamination growth if mode mix is important.

  1. Microscopic studies of the influence of main exposure time on parameters of flexographic printing plate produced by digital thermal method.

    Science.gov (United States)

    Harri, Liliya

    2009-10-01

    The digital thermal technology of producing flexographic printing plates from photopolymer plates is one of the newest technologies. This technology allows to develop flexographic plates without the use of any solvent. The process of producing flexographic printing plates by the digital thermal method consists of several main stages: back exposure, laser exposure, main exposure, thermal development, post exposure, and light finishing. The studies carried out with the use of optical stereoscopic microscopy allowed to determine the effect of time of main exposure to ultraviolet radiation on the dot area, diameter, and edge factor of halftone dots reproduced on flexographic printing plate produced by the digital thermal method, as well as on the quality of reproducing the surface and on the profiles of free-standing printing microelements. The results of the microscopic studies performed have allowed to define the criteria of establishing optimum time of main exposure of photopolymer plates used in the digital thermal technology of producing flexographic printing plates. A precise definition of the criteria for determining the optimum time of main exposure will enable to reduce the time-consuming control tests and to eliminate errors in both the process of manufacturing flexographic printing plates and in the printing process carried out with the use of such plates.

  2. Local wall shear stress measurements with a thin plate submerged in the sublayer in wall turbulent flows

    Science.gov (United States)

    Hua, Dan; Suzuki, Hiroki; Mochizuki, Shinsuke

    2017-09-01

    A local wall shear stress measurement technique has been developed using a thin plate, referred to as a sublayer plate which is attached to the wall in the sublayer of a near-wall turbulent flow. The pressure difference between the leading and trailing edges of the plate is correlated to the known wall shear stress obtained in the fully developed turbulent channel flow. The universal calibration curve can be well represented in dimensionless form, and the sensitivity of the proposed method is as high as that of the sublayer fence, even if the sublayer fence is enveloped by the linear sublayer. The results of additional experiments prove that the sublayer plate has fairly good angular resolution in detecting the direction of the local wall shear stress vector.

  3. Simulation and Experimental Investigation of Thermal Performance of a Miniature Flat Plate Heat Pipe

    Directory of Open Access Journals (Sweden)

    R. Boukhanouf

    2013-01-01

    Full Text Available This paper presents the results of a CFD analysis and experimental tests of two identical miniature flat plate heat pipes (FPHP using sintered and screen mesh wicks and a comparative analysis and measurement of two solid copper base plates 1 mm and 3 mm thick. It was shown that the design of the miniature FPHP with sintered wick would achieve the specific temperature gradients threshold for heat dissipation rates of up to 80 W. The experimental results also revealed that for localised heat sources of up to 40 W, a solid copper base plate 3 mm thick would have comparable heat transfer performances to that of the sintered wick FPHP. In addition, a marginal effect on the thermal performance of the sintered wick FPHP was recorded when its orientation was held at 0°, 90°, and 180° and for heat dissipation rates ranging from 0 to 100 W.

  4. Thin-layer chromatography and mass spectrometry coupled using proximal probe thermal desorption with electrospray or atmospheric pressure chemica lionization

    Energy Technology Data Exchange (ETDEWEB)

    Ovchinnikova, Olga S [ORNL; Van Berkel, Gary J [ORNL

    2010-01-01

    An atmospheric pressure proximal probe thermal desorption sampling method coupled with secondary ionization by electrospray or atmospheric pressure chemical ionization was demonstrated for the mass spectrometric analysis of a diverse set of compounds (dyestuffs, pharmaceuticals, explosives and pesticides) separated on various high-performance thin-layer chromatography plates. Line scans along or through development lanes on the plates were carried out by moving the plate relative to a stationary heated probe positioned close to or just touching the stationary phase surface. Vapors of the compounds thermally desorbed from the surface were drawn into the ionization region of a combined electrospray ionization/atmospheric pressure chemical ionization source where they merged with reagent ions and/or charged droplets from a corona discharge or an electrospray emitter and were ionized. The ionized components were then drawn through the atmospheric pressure sampling orifice into the vacuum region of a triple quadrupole mass spectrometer and detected using full scan, single ion monitoring, or selected reaction monitoring mode. Studies of variable parameters and performance metrics including the proximal probe temperature, gas flow rate into the ionization region, surface scan speed, read-out resolution, detection limits, and surface type are discussed.

  5. Numerical analysis of thermal deformation in laser beam heating of a steel plate

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Chao; Kim, Yong-Rae; Kim, Jae-Woong [Yeungnam University, Kyongsan (Korea, Republic of)

    2017-05-15

    Line heating is a widely used process for plate forming or thermal straightening. Flame heating and induction heating are the traditional heating processes used by industry for line heating. However, these two heating processes are ineffective when used on small steel plates. Thus, the laser beam heating with various power profiles were carried out in this study. A comparison of numerical simulation results and experimental results found a significant difference in the thermal deformation when apply a different power profile of laser beam heating. The one-sinusoid power profile produced largest thermal deformation in this study. The laser beam heating process was simulated by established a combined heat source model, and simulated results were compared with experimental results to confirm the model’s accuracy. The mechanism of thermal deformation was investigated and the effects of model parameters were studied intensively with the finite element method. Thermal deformation was found to have a significant relationship with the amount of central zone plastic deformation. Scientists and engineers could use this study’s verified model to select appropriate parameters in laser beam heating process. Moreover, by using the developed laser beam model, the analysis of welding residual stress or hardness could also be investigated from a power profile point of view.

  6. Thermal response simulation for tuning PID controllers in a 1016 mm guarded hot plate apparatus.

    Science.gov (United States)

    Thomas, William C; Zarr, Robert R

    2011-07-01

    A mathematical model has been developed and used to simulate the controlled thermal performance of a large guarded hot-plate apparatus. This highly specialized apparatus comprises three interdependent components whose temperatures are closely controlled in order to measure the thermal conductivity of insulation materials. The simulation model was used to investigate control strategies and derive controller gain parameters that are directly transferable to the actual instrument. The simulations take orders-of-magnitude less time to carry out when compared to traditional tuning methods based on operating the actual apparatus. The control system consists primarily of a PC-based PID control algorithm that regulates the output voltage of programmable power amplifiers. Feedback parameters in the form of controller gains are required for the three heating circuits. An objective is to determine an improved set of gains that meet temperature control criteria for testing insulation materials of interest. The analytical model is based on aggregated thermal capacity representations of the primary components and includes the same control algorithm as used in the actual hot-plate apparatus. The model, accounting for both thermal characteristics and temperature control, was validated by comparisons with test data. The tuning methodology used with the simulation model is described and results are presented. The resulting control algorithm and gain parameters have been used in the actual apparatus without modification during several years of testing materials over wide ranges of thermal conductivity, thickness, and insulation resistance values. Published by Elsevier Ltd on behalf of ISA.

  7. Entropy analysis of flow and heat transfer caused by a moving plate with thermal radiation

    Energy Technology Data Exchange (ETDEWEB)

    Butt, Adnan Saeed; Ali, Asif [Quaid-i-Azam University, Islamabad (Pakistan)

    2014-01-15

    This study examines the effects of thermal radiation on entropy generation in flow and heat transfer caused by a moving plate. The equations that govern the flow and heat transfer phenomenon are solved numerically. Velocity and temperature profiles are obtained for the parameters involved in the problem. The expressions for the entropy generation number and the Bejan number are obtained based on the profiles. Graphs for velocity, temperature, the entropy generation number, and the Bejan number are plotted and discussed qualitatively.

  8. Mixed Convective Flow of an Elastico-Viscous Fluid Past a Vertical Plate in the Presence of Thermal Radiation and Chemical Reaction with an Induced Magnetic Field

    Science.gov (United States)

    Das, Utpal Jyoti

    2016-01-01

    The purpose of the study is to investigate the steady, two-dimensional, hydromagnetic, mixed convection heat and mass transfer of a conducting, optically thin, incompressible, elastico-viscous fluid (characterized by the Walters' B' model) past a permeable, stationary, vertical, infinite plate in the presence of thermal radiation and chemical reaction with account for an induced magnetic field. The governing equations of the flow are solved by the series method, and expressions for the velocity field, induced magnetic field, temperature field, and the skin friction are obtained.

  9. Cracking behavior of thin gold strip deposited on polycarbonate plate under Cyclic and stepwisely-increased tension

    Directory of Open Access Journals (Sweden)

    Tada Naoya

    2017-01-01

    Full Text Available Thin metal films deposited on polymers have been attracting much attention in flexible electronics. Various combinations of film and polymer substrate are expected to be developed. In this paper, deformation and fracture of thin metal film on polymer substrate was briefly analysed and the influencing factors were summarized. After that, focusing on the shape and thickness of thin metal film on polymer substrate, cracking behavior of small rounded-rectangular thin gold films called “strips” with a thickness less than one micrometer was observed under cyclic and stepwisely-increased trapezoidal tensions. The strips were deposited on a polycarbonate plate specimen, and wide and narrow strips with different thickness were prepared for the tests. The cracking behaviour was successfully observed and the increasing rate of crack number with the load or strain was examined. Since most cracks were initiated from the small defects, the crack initiation behavior was correlated with the distribution of defects.

  10. Effect of growth on the thermal resistance and survival of Salmonella Tennessee and Oranienburg in peanut butter, measured by a new thin-layer thermal death time device.

    Science.gov (United States)

    Keller, Susanne E; Grasso, Elizabeth M; Halik, Lindsay A; Fleischman, Gregory J; Chirtel, Stuart J; Grove, Stephen F

    2012-06-01

    In published data the thermal destruction of Salmonella species in peanut butter deviates from pseudo-first-order kinetics. The reasons for such deviation are unknown. This study examined both the method used to measure the thermal destruction rate and the method of growth of the microorganisms to explain variations in destruction kinetics. Growth on a solid matrix results in a different physiological state that may provide greater resistance to adverse environments. In this study, Salmonella Tennessee and Oranienburg were grown for 24 h at 37°C under aerobic conditions in broth and agar media to represent planktonic and sessile cell growth, respectively. Peanut butter was held at 25°C and tested for Salmonella levels immediately after inoculation and at various time intervals up to 2 weeks. Thermal resistance was measured at 85°C by use of a newly developed thin-layer metal sample holder. Although thermal heat transfer through the metal device resulted in longer tau values than those obtained with plastic bags (32.5 ± 0.9 versus 12.4 ± 1.9 s), the bags have a relative variability of about 15 % compared with about 3 % in the plates, allowing improved uniformity of sample treatment. The two serovars tested in the thin-layer device showed similar overall thermal resistance levels in peanut butter regardless of growth in sessile or planktonic states. However, thermal destruction curves from sessile cultures exhibited greater linearity than those obtained from planktonic cells (P = 0.0198 and 0.0047 for Salmonella Oranienburg and Salmonella Tennessee, respectively). In addition, both Salmonella serovars showed significantly higher survival in peanut butter at 25°C when originally grown on solid media (P = 0.001) with a survival of Salmonella at different temperatures in a low-water-activity environment such as peanut butter.

  11. Boundary integral equation methods and numerical solutions thin plates on an elastic foundation

    CERN Document Server

    Constanda, Christian; Hamill, William

    2016-01-01

    This book presents and explains a general, efficient, and elegant method for solving the Dirichlet, Neumann, and Robin boundary value problems for the extensional deformation of a thin plate on an elastic foundation. The solutions of these problems are obtained both analytically—by means of direct and indirect boundary integral equation methods (BIEMs)—and numerically, through the application of a boundary element technique. The text discusses the methodology for constructing a BIEM, deriving all the attending mathematical properties with full rigor. The model investigated in the book can serve as a template for the study of any linear elliptic two-dimensional problem with constant coefficients. The representation of the solution in terms of single-layer and double-layer potentials is pivotal in the development of a BIEM, which, in turn, forms the basis for the second part of the book, where approximate solutions are computed with a high degree of accuracy. The book is intended for graduate students and r...

  12. PLATE

    DEFF Research Database (Denmark)

    Kling, Joyce; Hjulmand, Lise-Lotte

    2008-01-01

    the Project in Language Assessment for Teaching in English (PLATE) language professionals from CBS’s Language Center observe teachers and provide feedback using evaluation criteria from the Common European Framework for Reference (CEFR) supplemented by some additional criteria which take the LSP nature......’s level of English is sufficient for the increasing number of courses offered in English each semester. This paper addresses these concerns and describes a pilot project initiated in 2003 at CBS to gauge the overall English language proficiency of those teaching content courses in English. Through...

  13. Effective thermal conductivity of a thin composite material

    Energy Technology Data Exchange (ETDEWEB)

    Phelan, P.E. [Arizona State Univ., Tempe, AZ (United States). Dept. of Mechanical and Aerospace Engineering; Niemann, R.C. [Argonne National Lab., IL (United States)

    1996-12-31

    The thermal conductivity of a randomly oriented composite material is modeled using a probabilistic approach in order to determine if a size effect exists for the thermal conductivity at small composite thickness. The numerical scheme employs a random number generator to position the filler elements, which have a relatively high thermal conductivity, within a matrix having a relatively low thermal conductivity. Results indicate that, below some threshold thickness, the composite thermal conductivity increases with decreasing thickness, while above the threshold the thermal conductivity is independent of thickness. The threshold thickness increases for increasing filler fraction and increasing k{sub f}/k{sub m}, the ratio between filler and matrix thermal conductivities.

  14. Thermal Stresses Analysis and Optimized TTP Processes to Achieved CNT-Based Diaphragm for Thin Panel Speakers

    Directory of Open Access Journals (Sweden)

    Feng-Min Lai

    2016-01-01

    Full Text Available Industrial companies popularly used the powder coating, classing, and thermal transfer printing (TTP technique to avoid oxidation on the metallic surface and stiffened speaker diaphragm. This study developed a TTP technique to fabricate a carbon nanotubes (CNTs stiffened speaker diaphragm for thin panel speaker. The self-developed TTP stiffening technique did not require a high curing temperature that decreased the mechanical property of CNTs. In addition to increasing the stiffness of diaphragm substrate, this technique alleviated the middle and high frequency attenuation associated with the smoothing sound pressure curve of thin panel speaker. The advantage of TTP technique is less harmful to the ecology, but it causes thermal residual stresses and some unstable connections between printed plates. Thus, this study used the numerical analysis software (ANSYS to analyze the stress and thermal of work piece which have not delaminated problems in transfer interface. The Taguchi quality engineering method was applied to identify the optimal manufacturing parameters. Finally, the optimal manufacturing parameters were employed to fabricate a CNT-based diaphragm, which was then assembled onto a speaker. The result indicated that the CNT-based diaphragm improved the sound pressure curve smoothness of the speaker, which produced a minimum high frequency dip difference (ΔdB value.

  15. Effect of electronic contribution on temperature-dependent thermal transport of antimony telluride thin film

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Won-Yong; Park, No-Won [Department of Physics, Chung-Ang University, Seoul 156-756 (Korea, Republic of); Hong, Ji-Eun [Department of Materials Engineering, Chungnam National University, Daejeon 305-764 (Korea, Republic of); Yoon, Soon-Gil, E-mail: sgyoon@cnu.ac.kr [Department of Materials Engineering, Chungnam National University, Daejeon 305-764 (Korea, Republic of); Koh, Jung-Hyuk [School of Electrical and Electronics Engineering, Chung-Ang University, Seoul 156-756 (Korea, Republic of); Lee, Sang-Kwon, E-mail: sangkwonlee@cau.ac.kr [Department of Physics, Chung-Ang University, Seoul 156-756 (Korea, Republic of)

    2015-01-25

    Highlights: • We investigated thermal transport of the antimony telluride thin films. • The contribution of the electronic thermal conductivity increased up to ∼77% at 300 K. • We theoretically analyze and explain the high contribution of electronic component. - Abstract: We study the theoretical and experimental characteristics of thermal transport of 100 nm and 500 nm-thick antimony telluride (Sb{sub 2}Te{sub 3}) thin films prepared by radio frequency magnetron sputtering. The thermal conductivity was measured at temperatures ranging from 20 to 300 K, using four-point-probe 3-ω method. Out-of-plane thermal conductivity of the Sb{sub 2}Te{sub 3} thin film was much lesser in comparison to the bulk material in the entire temperature range, confirming that the phonon- and electron-boundary scattering are enhanced in thin films. Moreover, we found that the contribution of the electronic thermal conductivity (κ{sub e}) in total thermal conductivity (κ) linearly increased up to ∼77% at 300 K with increasing temperature. We theoretically analyze and explain the high contribution of electronic component of thermal conductivity towards the total thermal conductivity of the film by a modified Callaway model. Further, we find the theoretical model predictions to correspond well with the experimental results.

  16. Combined visualization for noise mapping of industrial facilities based on ray-tracing and thin plate splines

    Science.gov (United States)

    Ovsiannikov, Mikhail; Ovsiannikov, Sergei

    2017-01-01

    The paper presents the combined approach to noise mapping and visualizing of industrial facilities sound pollution using forward ray tracing method and thin-plate spline interpolation. It is suggested to cauterize industrial area in separate zones with similar sound levels. Equivalent local source is defined for range computation of sanitary zones based on ray tracing algorithm. Computation of sound pressure levels within clustered zones are based on two-dimension spline interpolation of measured data on perimeter and inside the zone.

  17. Design of plate directional heat transmission structure based on layered thermal metamaterials

    Science.gov (United States)

    Sun, L. K.; Yu, Z. F.; Huang, J.

    2016-02-01

    Invisibility cloaks based on transformation optics are often closed structures; however, such a structure limits the kinds of objects that can be placed in the cloak. In this work, we adopt a transformation thermodynamics approach to design an "open cloak", called a plate directional heat transmission structure, which is capable of guiding heat fluxes to the flank region of the metamaterial device. The most fascinating and unique feature of the device is that the lower surface can remain at a lower temperature compared with the SiO2 aerogel thermal insulation material. Our results are expected to markedly enhance capabilities in thermal protection, thermal-energy utilization, and domains beyond. In addition to the theoretical analysis, the present design is demonstrated in numerical simulations based on finite element calculations.

  18. Design of plate directional heat transmission structure based on layered thermal metamaterials

    Energy Technology Data Exchange (ETDEWEB)

    Sun, L. K.; Yu, Z. F.; Huang, J., E-mail: slk-0-1999@163.com [China Aerodynamics Research and Development Center, Mianyang 621000 (China)

    2016-02-15

    Invisibility cloaks based on transformation optics are often closed structures; however, such a structure limits the kinds of objects that can be placed in the cloak. In this work, we adopt a transformation thermodynamics approach to design an “open cloak”, called a plate directional heat transmission structure, which is capable of guiding heat fluxes to the flank region of the metamaterial device. The most fascinating and unique feature of the device is that the lower surface can remain at a lower temperature compared with the SiO{sub 2} aerogel thermal insulation material. Our results are expected to markedly enhance capabilities in thermal protection, thermal-energy utilization, and domains beyond. In addition to the theoretical analysis, the present design is demonstrated in numerical simulations based on finite element calculations.

  19. Design of plate directional heat transmission structure based on layered thermal metamaterials

    Directory of Open Access Journals (Sweden)

    L. K. Sun

    2016-02-01

    Full Text Available Invisibility cloaks based on transformation optics are often closed structures; however, such a structure limits the kinds of objects that can be placed in the cloak. In this work, we adopt a transformation thermodynamics approach to design an “open cloak”, called a plate directional heat transmission structure, which is capable of guiding heat fluxes to the flank region of the metamaterial device. The most fascinating and unique feature of the device is that the lower surface can remain at a lower temperature compared with the SiO2 aerogel thermal insulation material. Our results are expected to markedly enhance capabilities in thermal protection, thermal-energy utilization, and domains beyond. In addition to the theoretical analysis, the present design is demonstrated in numerical simulations based on finite element calculations.

  20. Improved behavior of cooper-amine complexes during thermal annealing for conductive thin film synthesis

    Energy Technology Data Exchange (ETDEWEB)

    Ayag, Kevin Ray; Panama, Gustavo; Paul, Shrabani; Kim, Hong Doo [Dept. of Advanced Materials Engineering for Information and Electronics, Kyung Hee University, Yongin (Korea, Republic of)

    2017-02-15

    Previous studies successfully produced conductive thin films from organo-metallic-compounds-based inks. Some inks like those made from copper salt and amines, however, tend to move during thermal annealing and, thus, affect the conductive pattern on the substrate. In this study, conductive inks were synthesized by forming complexes of copper with amines and/or blended amines. To build-up an organo-metallic framework and preserve the pattern throughout the annealing period, diamine was added to the complex in different proportions. The prepared inks were coated on glass substrate and were annealed on a hot plate at 170°C under the gaseous mixture of formic acid and alcohol for 5 min. The metallic film was observed to retain the original pattern of the ink during and after annealing. Adhesion on the substrate was also improved. Inks with blended amines produced films with lower resistivities. The lowest electrical resistivity recorded was 4.99 μΩ cm, three times that of bulk copper.

  1. A Study on the Application of Submerged Arc Welding for Thin Plate of A-Grade 3.2 Thickness Steel in Ship Structure

    Science.gov (United States)

    Lee, Jeong-Soo; Yun, Jin-Oh; Lim, Dong-Yong; Jang, Yong-Won; Kim, Bong-Joon; Oh, Chong-In

    2010-06-01

    This paper is focused on application submerged arc welding process, which offers many advantages compared to conventional CO2 welding process, for thin plate in ship structure. For this purpose, optimized welding conditions are determined according to combination of wire & flux, relationship between welding parameters, bead shapes and mechanical tests such as tensile, bend and hardness. Also finite element(FE) based numerical simulation of thermal history and welding residual stress in welded joint of A-grade 3.2 thickness steel has been checked to qualitative tendency in this paper. In conclusion our company applied to this method in work piece and it was no problem. From the result of this study, it makes substantial saving of time and manufacturing cost and raises the welding quality of product.

  2. Hot Plate Method with Two Simultaneous Temperature Measurements for Thermal Characterization of Building Materials

    Science.gov (United States)

    Osséni, Sibiath O. G.; Ahouannou, Clément; Sanya, Emile A.; Jannot, Yves

    2017-07-01

    This paper presents a study of the hot plate method with two simultaneous temperature measurements, on the heated and unheated faces of a sample to characterize. The thermal properties of polyvinyl chloride, plaster and laterite were considered to be a representative range of building materials. A 1D quadrupolar model was developed to represent the temperature evolution on the two faces over time. Three-dimensional numerical modeling of a quarter of the testing device with COMSOL software allowed defining the domain of the 1D hypothesis validity. The analysis of estimation possibilities of materials' thermal characteristics, with the developed method, revealed that thermal effusivity can be accurately estimated by using the temperature of the heated face at the beginning of heating. We showed that the simultaneous use of two temperatures enables the estimation of the thermal conductivity with a greater accuracy and over a shorter time interval than using the temperature of the heated face alone. We also demonstrated that under certain conditions (samples with a high ratio of thickness to width) the method with two temperature measurements enabled the estimation of the thermal effusivity and conductivity, while the method with one temperature allowed only the thermal effusivity to be estimated, because of 3D effects. This conclusion was confirmed by experimental results obtained with a mortar sample.

  3. Thermally stimulated nonlinear refraction in gelatin stabilized Cu-PVP nanocomposite thin films

    Energy Technology Data Exchange (ETDEWEB)

    Tamgadge, Y. S., E-mail: ystamgadge@gmail.com; Atkare, D. V. [Department of Physics, Mahatma Fule Arts, Commerce & SitaramjiChoudhari Science College, Warud, Dist. Amravati (MS), India-444906 (India); Pahurkar, V. G.; Muley, G. G., E-mail: gajananggm@yahoo.co.in [Department of Physics, SantGadge Baba Amravati University, Amravati (MS), India-444602 (India); Talwatkar, S. S. [Department of Physics, D K Marathe and N G Acharya College, Chembur, Mumbai (MS), India-440071 (India); Sunatkari, A. L. [Department of Physics, Siddharth College of Arts, Science and Commerce, Fort, Mumbai (MS), India-440001 (India)

    2016-05-06

    This article illustrates investigations on thermally stimulated third order nonlinear refraction of Cu-PVP nanocomposite thin films. Cu nanoparticles have been synthesized using chemical reduction method and thin films in PVP matrix have been obtained using spin coating technique. Thin films have been characterized by X-ray diffraction (XRD) and Ultraviolet-visible (UV-vis) spectroscopyfor structural and linear optical studies. Third order nonlinear refraction studies have been performed using closed aperture z-scan technique under continuous wave (CW) He-Ne laser. Cu-PVP nanocomposites are found to exhibit strong nonlinear refractive index stimulated by thermal lensing effect.

  4. Thin plate gap bridging study for Nd:YAG pulsed laser lap welds.

    Energy Technology Data Exchange (ETDEWEB)

    Roach, Robert Allen; Fuerschbach, Phillip William; Bernal, John E.; Norris, Jerome T.

    2006-01-01

    In an on going study of gap bridging for thin plate Nd:YAG laser lap welds, empirical data, high speed imaging, and computer modeling were utilized to better understand surface physics attributed to the formation and solidification of a weld pool. Experimental data indicates better gap bridging can be achieved through optimized laser parameters such as pulse length, duration, and energy. Long pulse durations at low energies generating low peak powers were found to create the highest percent of gap bridging ability. At constant peak power, gap-bridging ability was further improved by using a smaller spot diameter resulting in higher irradiances. Hence, welding in focus is preferable for bridging gaps. Gas shielding was also found to greatly impact gap-bridging ability. Gapped lap welds that could not be bridged with UHP Argon gas shielding, were easily bridged when left unshielded and exposed to only air. Incident weld angle and joint offset were also investigated for their ability to improve gap bridging. Optical filters and brightlight surface illumination enabled high-speed imaging to capture the fluid dynamics of a forming and solidifying weld pool. The effects of various laser parameters and the weld pool's interaction with the laser beam could also be observed utilizing the high-speed imaging. The work described is used to develop and validate a computer model with improved weld pool physics. Finite element models have been used to derive insight into the physics of gap bridging. The dynamics of the fluid motion within the weld pool in conjunction with the free surface physics have been the primary focus of the modeling efforts. Surface tension has been found to be a more significant factor in determining final weld pool shape than expected.

  5. The signatures of acoustic emission waveforms from fatigue crack advancing in thin metallic plates

    Science.gov (United States)

    Yeasin Bhuiyan, Md; Giurgiutiu, Victor

    2018-01-01

    The acoustic emission (AE) waveforms from a fatigue crack advancing in a thin metallic plate possess diverse and complex spectral signatures. In this article, we analyze these waveform signatures in coordination with the load level during cyclic fatigue. The advancing fatigue crack may generate numerous AE hits while it grows under fatigue loading. We found that these AE hits can be sorted into various groups based on their AE waveform signatures. Each waveform group has a particular time-domain signal pattern and a specific frequency spectrum. This indicates that each group represents a certain AE event related to the fatigue crack growth behavior. In situ AE-fatigue experiments were conducted to monitor the fatigue crack growth with simultaneous measurement of AE signals, fatigue loading, and optical crack growth measurement. An in situ microscope was installed in the load-frame of the mechanical testing system (MTS) to optically monitor the fatigue crack growth and relate the AE signals with the crack growth measurement. We found the AE signal groups at higher load levels (75%–85% of maximum load) were different from the AE signal groups that happened at lower load levels (below 60% of load level). These AE waveform groups are highly related to the fatigue crack-related AE events. These AE signals mostly contain the higher frequency peaks (100 kHz, 230 kHz, 450 kHz, 550 kHz). Some AE signal groups happened as a clustered form that relates a sequence of small AE events within the fatigue crack. They happened at relatively lower load level (50%–60% of the maximum load). These AE signal groups may be related to crack friction and micro-fracture during the friction process. These AE signals mostly contain the lower frequency peaks (60 kHz, 100 kHz, 200 kHz). The AE waveform based analysis may give us comprehensive information of the metal fatigue.

  6. Influence of the ambient pressure on thin plate and film bending

    Science.gov (United States)

    Ilgamov, M. A.

    2017-10-01

    The distributed lateral load on a plate located in a gas medium has been determined. The difference in the gas pressures of the plate surfaces results in a pressure drop and a lateral force, which depends on the middle surface curvature. It is shown that both these components of the lateral force must be taken into account in the general case. The influence of the second load component is small at a small ratio of the average pressure to the elastic modulus of the plate material and at a large relative thickness of the plate. At a small relative plate thickness and a large ratio of the average pressure of the medium to the elastic modulus of the plate material, the influence of the second component of the lateral load on the bending becomes significant. Cases of both linear and nonlinear plate bending are considered.

  7. Thermal convection of viscoelastic shear-thinning fluids

    Science.gov (United States)

    Albaalbaki, Bashar; Khayat, Roger E.; Ahmed, Zahir U.

    2016-12-01

    The Rayleigh-Bénard convection for non-Newtonian fluids possessing both viscoelastic and shear-thinning behaviours is examined. The Phan-Thien-Tanner (PTT) constitutive equation is implemented to model the non-Newtonian character of the fluid. It is found that while the shear-thinning and viscoelastic effects could annihilate one another for the steady roll flow, presence of both behaviours restricts the roll stability limit significantly compared to the cases when the fluid is either inelastic shear-thinning or purely viscoelastic with constant viscosity.

  8. An Analytical Approach on Thermally Induced Vibrations of Nonhomogeneous Tapered Plate

    Directory of Open Access Journals (Sweden)

    Anupam Khanna

    2013-01-01

    Full Text Available A mathematical model to control the vibrations of a rectangular plate is constructed with an aim to assist engineers in designing and fabrication of various structures used in the field of science and technology, mostly used in satellite and aeronautical engineering. The present study is related to the analysis of free vibrations of nonhomogeneous rectangular plate clamped at all the four edges. Authors studied the bilinear effect of thickness as well as temperature variations in both and directions. Variation in Poisson's ratio is also considered linearly in -direction due to nonhomogeneity. Rayleigh-Ritz method is used to analyze the frequencies for the first two modes of vibrations for different values of thermal gradient, nonhomogeneity constant, taper constants and aspect ratio. All the numerical computations have been performed for an alloy of aluminum, that is, duralumin. All the results are presented in the form of graphs.

  9. Vibration and Acoustic Response of Rectangular Sandwich Plate under Thermal Environment

    Directory of Open Access Journals (Sweden)

    Yuan Liu

    2013-01-01

    Full Text Available In this paper, we focus on the vibration and acoustic response of a rectangular sandwich plate which is subjected to a concentrated harmonic force under thermal environment. The critical buckling temperature is obtained to decide the thermal load. The natural frequencies and modes as well as dynamic responses are acquired by using the analytical formulations based on equivalent non-classical theory, in which the effects of shear deformation and rotational inertia are taken into account. The rise of thermal load decreases the natural frequencies and moves response peaks to the low-frequency range. The specific features of sandwich plates with different formations are discussed subsequently. As the thickness ratio of facing to core increases, the natural frequencies are enlarged, and the response peaks float to the high-frequency region. Raising the Young's modulus of the core can cause the similar trends. The accuracy of the theoretical method is verified by comparing its results with those computed by the FEM/BEM.

  10. Transient thermal hydraulic modeling and analysis of ITER divertor plate system

    Energy Technology Data Exchange (ETDEWEB)

    El-Morshedy, Salah El-Din [Argonne National Laboratory, Argonne, IL (United States); Atomic Energy Authority, Cairo (Egypt)], E-mail: selmorshedy@etrr2-aea.org.eg; Hassanein, Ahmed [Purdue University, West Lafayette, IN (United States)], E-mail: hassanein@purdue.edu

    2009-12-15

    A mathematical model has been developed/updated to simulate the steady state and transient thermal-hydraulics of the International Thermonuclear Experimental Reactor (ITER) divertor module. The model predicts the thermal response of the armour coating, divertor plate structural materials and coolant channels. The selected heat transfer correlations cover all operating conditions of ITER under both normal and off-normal situations. The model also accounts for the melting, vaporization, and solidification of the armour material. The developed model is to provide a quick benchmark of the HEIGHTS multidimensional comprehensive simulation package. The present model divides the coolant channels into a specified axial regions and the divertor plate into a specified radial zones, then a two-dimensional heat conduction calculation is created to predict the temperature distribution for both steady and transient states. The model is benchmarked against experimental data performed at Sandia National Laboratory for both bare and swirl tape coolant channel mockups. The results show very good agreements with the data for steady and transient states. The model is then used to predict the thermal behavior of the ITER plasma facing and structural materials due to plasma instability event where 60 MJ/m{sup 2} plasma energy is deposited over 500 ms. The results for ITER divertor response is analyzed and compared with HEIGHTS results.

  11. Measurements of thermal conductivity and the coefficient of thermal expansion for polysilicon thin films by using double-clamped beams

    Science.gov (United States)

    Liu, Haiyun; Wang, Lei

    2018-01-01

    In this paper, a test structure for simultaneously determining thermal conductivity and the coefficient of thermal expansion (CTE) of polysilicon thin film is proposed. The test structure consists of two double-clamped beams with different lengths. A theoretical model for extracting thermal conductivity and CTE based on electrothermal analysis and resonance frequency approach is developed. Both flat and buckled beams are considered in the theoretical model. The model is confirmed by finite element software ANSYS. The test structures are fabricated by surface micromachined fabrication process. Experiments are carried out in our atmosphere. Thermal conductivity and CTE of polysilicon thin film are obtained to be (29.96  ±  0.92) W · m · K‑1 and (2.65  ±  0.03)  ×  10‑6 K‑1, respectively, with temperature ranging from 300–400 K.

  12. Thermal Management Investigations in Ceramic Thin Disk Lasers

    Science.gov (United States)

    2011-01-14

    new alternative is the use of ceramic materials. Highly translucent and low scattering ceramic materials have been produced using purely chemical...MANAGEMENT INVESTIGATIONS IN CERAMIC THIN DISK LASERS William P. Latham et al. 14 January 2011 Technical Note...Investigations in Ceramic Thin Disk Lasers 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 63605F 6. AUTHOR(S) 5d. PROJECT NUMBER

  13. Gas Control and Thermal Modeling Methods for Pressed Pellet and Fast Rise Thin-Film Thermal Batteries

    Science.gov (United States)

    2015-09-01

    high operating battery case temperatures. Acceptable hermetic seals for thermal batteries ordinarily use laser welding , tungsten inert gas ( TIG ... welding , or high temperature (~1000 °C) melting point silver solder methods. 31 Thin-walled thermal battery cases can be hermetically sealed for gas...high temperature attachment of standard gas collection fittings using high temperature attachment methods such as laser welding with external

  14. End plate for e.g. solid oxide fuel cell stack, sets thermal expansion coefficient of material to predetermined value

    DEFF Research Database (Denmark)

    2011-01-01

    .05-0.3 mm. USE - End plate for solid oxide fuel cell stack (claimed). Can also be used in polymer electrolyte fuel cell stack and direct methanol fuel cell stack. ADVANTAGE - The robustness of the end plate is improved. The structure of the end plate is simplified. The risk of delamination of the stack......NOVELTY - The end plate is made of material whose thermal expansion coefficient is corresponding to that of material of a cell (103). The thermal expansion coefficient of material is 9asterisk10-6 K-1 to 14asterisk10-6 K11. The thickness of the end plate is within the range of 0.001-1 mm and 0...

  15. Regional variations in subsidence rate of lithospheric plates: implication for thermal cooling models

    Science.gov (United States)

    Lago, Bernard; Cazenave, Anny; Marty, Jean-Charles

    Although simple thermal models of lithospheric cooling predict to first order the general behaviour of observed seafloor depth with increasing age, important regional variations in seafloor subsidence, in the range 250-400 m Ma1/2, are reported for several lithospheric plates. Such variations cannot be accounted for by classical cooling models unless implausible variations in asthenospheric temperature of ˜550°C are assumed. Here we present an alternative cooling model, which assumes that at the ridge axis the temperature may deviate from the mean asthenospheric temperature. Such a model satisfactorily explains the data provided that the temperature deviation is ±100°C only.

  16. Thermal diffusion effects on free convection and mass transfer flow for an infinite vertical plate

    CERN Document Server

    Abdel-Khalek, M M

    2003-01-01

    A theoretical study is performed to examine the effects of thermal diffusion on free convection and mass transfer flow for an infinite vertical plate. The governing equations for the fluid flow and the heat transfer are solved subject to the relevant boundary conditions. A perturbation technique is used to obtain expressions for the velocity field and skin friction. An analysis of the effects of the parameters on the concentration, velocity and temperature profiles as well as skin friction and the rate of mass and heat transfer is done with the aid of graphs.

  17. Analytical model of unsteady-state convective heat transfer between the heat carrier and the finite sizes plate adjusted for the thermal relaxation

    Directory of Open Access Journals (Sweden)

    Makarushkin Danila

    2017-01-01

    Full Text Available A hyperbolic boundary value problem of the thermal conduction of a two-dimensional plate with the third kind boundary conditions is formulated. The transient thermal process in the plate is due to the temperature changes of the external medium over time and along the plate length, and also by a multiple step change of the plate surface heat transfer coefficient throughout the transient process. An analytical solution with improved convergence adjusted for thermal relaxation and thermal damping is obtained for the temperature field in the plate.

  18. Evaluation of Thin Plate Hydrodynamic Stability through a Combined Numerical Modeling and Experimental Effort

    Energy Technology Data Exchange (ETDEWEB)

    Tentner, A. [Argonne National Lab. (ANL), Argonne, IL (United States); Bojanowski, C. [Argonne National Lab. (ANL), Argonne, IL (United States); Feldman, E. [Argonne National Lab. (ANL), Argonne, IL (United States); Wilson, E. [Argonne National Lab. (ANL), Argonne, IL (United States); Solbrekken, G [Univ. of Missouri, Columbia, MO (United States); Jesse, C. [Univ. of Missouri, Columbia, MO (United States); Kennedy, J. [Univ. of Missouri, Columbia, MO (United States); Rivers, J. [Univ. of Missouri, Columbia, MO (United States); Schnieders, G. [Univ. of Missouri, Columbia, MO (United States)

    2017-05-01

    An experimental and computational effort was undertaken in order to evaluate the capability of the fluid-structure interaction (FSI) simulation tools to describe the deflection of a Missouri University Research Reactor (MURR) fuel element plate redesigned for conversion to lowenriched uranium (LEU) fuel due to hydrodynamic forces. Experiments involving both flat plates and curved plates were conducted in a water flow test loop located at the University of Missouri (MU), at conditions and geometries that can be related to the MURR LEU fuel element. A wider channel gap on one side of the test plate, and a narrower on the other represent the differences that could be encountered in a MURR element due to allowed fabrication variability. The difference in the channel gaps leads to a pressure differential across the plate, leading to plate deflection. The induced plate deflection the pressure difference induces in the plate was measured at specified locations using a laser measurement technique. High fidelity 3-D simulations of the experiments were performed at MU using the computational fluid dynamics code STAR-CCM+ coupled with the structural mechanics code ABAQUS. Independent simulations of the experiments were performed at Argonne National Laboratory (ANL) using the STAR-CCM+ code and its built-in structural mechanics solver. The simulation results obtained at MU and ANL were compared with the corresponding measured plate deflections.

  19. Multi-objective genetic algorithm for the optimization of a flat-plate solar thermal collector.

    Science.gov (United States)

    Mayer, Alexandre; Gaouyat, Lucie; Nicolay, Delphine; Carletti, Timoteo; Deparis, Olivier

    2014-10-20

    We present a multi-objective genetic algorithm we developed for the optimization of a flat-plate solar thermal collector. This collector consists of a waffle-shaped Al substrate with NiCrOx cermet and SnO(2) anti-reflection conformal coatings. Optimal geometrical parameters are determined in order to (i) maximize the solar absorptance α and (ii) minimize the thermal emittance ε. The multi-objective genetic algorithm eventually provides a whole set of Pareto-optimal solutions for the optimization of α and ε, which turn out to be competitive with record values found in the literature. In particular, a solution that enables α = 97.8% and ε = 4.8% was found.

  20. Thin Plate Bumper Influence on Crater Formation in Thick Aluminum Targets

    Science.gov (United States)

    Nishida, Masahiro; Nakagawa, Junichi; Kuzuya, Kayoko; Aikawa, Fumiaki; Hayashi, Koichi; Tanaka, Koichi

    For studying the generation of space debris, we experimentally investigated the penetration of steel projectiles into thick targets made of aluminum alloy 5056 and the subsequent crater formation in the velocity range from 0.7 to 1.9 km/s using a two-stage light gas gun. We added 1- and 2-mm-thick pure nickel plates and 2-mm-thick aluminum alloy plates to the thick targets, and examined the effects of plate addition, plate material, and plate thickness on the crater shape (depth, diameter, depth/diameter ratio) and lip formation. The plate addition suppressed the formation of crater lips and changed the crater shape. In particular, addition of nickel plates decreased the crater diameter, depth, and depth/diameter ratio. Furthermore, component analyses by scanning electron microscopy indicated the presence of Ni-Al alloy near the crater wall and Ni-Fe alloy in the post-impact projectile when nickel plates were used.

  1. Thermal stability of gold-PS nanocomposites thin films

    Indian Academy of Sciences (India)

    The composite thin films were prepared by wet chemical approach and the samples were then subsequently spin-coated on a carbon-coated copper grid for TEM measurements. TEM measurements were performed at liquid nitrogen temperatures to reduce the electron–beam-induced radiation damage. The results showed ...

  2. Mobility activation in thermally deposited CdSe thin films

    Indian Academy of Sciences (India)

    Administrator

    temperatures (Ts), on chemically and ultrasonically cleaned glass substrates at a vacuum of the order of 10. –6 torr. Pure (99⋅999%) bulk CdSe sample was used as the source material. Prior to deposition of the thin films, high purity aluminium electrodes were vacuum evaporated on glass substrates on which the films ...

  3. Steady heat conduction-based thermal conductivity measurement of single walled carbon nanotubes thin film using a micropipette thermal sensor.

    Science.gov (United States)

    Shrestha, R; Lee, K M; Chang, W S; Kim, D S; Rhee, G H; Choi, T Y

    2013-03-01

    In this paper, we describe the thermal conductivity measurement of single-walled carbon nanotubes thin film using a laser point source-based steady state heat conduction method. A high precision micropipette thermal sensor fabricated with a sensing tip size varying from 2 μm to 5 μm and capable of measuring thermal fluctuation with resolution of ±0.01 K was used to measure the temperature gradient across the suspended carbon nanotubes (CNT) film with a thickness of 100 nm. We used a steady heat conduction model to correlate the temperature gradient to the thermal conductivity of the film. We measured the average thermal conductivity of CNT film as 74.3 ± 7.9 W m(-1) K(-1) at room temperature.

  4. Analysis of Thin Isotropic and Orthotropic Plates with Element-Free Galerkin Method and Various Geometric Shapes

    Directory of Open Access Journals (Sweden)

    H. Edalati

    2016-01-01

    Full Text Available Utilizing one of the mesh free methods, the present paper concerns static analysis of thin plates with various geometric shapes based on the mindlin classical plate theories. In this numerical method, the domain of issue is solely expressed through a set of nods and no gridding or element is required. To express the domain of issues with various geometric shapes, first a set of nodes are defined in a standard rectangular domain , then via a three-order map with, these nodes are transferred to the main domain of the original issue; therefore plates of various geometric shapes can be analyzed. Among meshfree numerical methods, Element Free Galerkin method (EFG is utilized here. The method is one of the weak form integral methods that uses MLS shape functions for approximation. Regarding the absence of Delta feature in MLS functions, boundary conditions cannot be imposed directly; hence the Lagrangian method is utilized to impose boundary conditions. At the end, our outputs are compared with those of analytic and finite element methods for plates, in order to validate the exactness of our solution method, and then after reliability is established, a few new examples will be solved.

  5. Minimization of the Vibration Energy of Thin-Plate Structures and the Application to the Reduction of Gearbox Vibration

    Science.gov (United States)

    Inoue, Katsumi; Krantz, Timothy L.

    1995-01-01

    While the vibration analysis of gear systems has been developed, a systematic approach to the reduction of gearbox vibration has been lacking. The technique of reducing vibration by shifting natural frequencies is proposed here for gearboxes and other thin-plate structures using the theories of finite elements, modal analysis, and optimization. A triangular shell element with 18 degrees of freedom is developed for structural and dynamic analysis. To optimize, the overall vibration energy is adopted as the objective function to be minimized at the excitation frequency by varying the design variable (element thickness) under the constraint of overall constant weight. Modal analysis is used to determine the sensitivity of the vibration energy as a function of the eigenvalues and eigenvectors. The optimum design is found by the gradient projection method and a unidimensional search procedure. By applying the computer code to design problems for beams and plates, it was verified that the proposed method is effective in reducing vibration energy. The computer code is also applied to redesign the NASA Lewis gear noise rig test gearbox housing. As one example, only the shape of the top plate is varied, and the vibration energy levels of all the surfaces are reduced, yielding an overall reduction of 1/5 compared to the initial design. As a second example, the shapes of the top and two side plates are varied to yield an overall reduction in vibration energy of 1/30.

  6. Application of the HHT Method to the Non-contact Thickness Measurement of an Axially Moving Thin Plate

    Science.gov (United States)

    Wu, Yangfang; Lu, Qianqian; Xia, Chunlin; Ding, Fan

    2017-08-01

    Non-contact thickness measuring systems can be found in a wide spectrum of technologies. In this paper, Hilbert-Huang transform method is used to analyze the real time signals of a measuring system which includes two round conveyor strings carrying a thin plate, a solar wafer as a sample under test. The vibrations of moving strings and the plate, which are sensitive to moving speed and initial tension in the string, are introduced briefly; the relevant analyses should be helpful for the system design. Using EMD-based time-domain filtering and complementary method, thickness variations and error bands are estimated for different cases. The results show that HHT method as an adaptive time-frequency method, should be potential in measurement engineering applications.

  7. Dynamic instability of a thin circular plate with friction interface and its application to disc brake squeal

    Science.gov (United States)

    Kang, Jaeyoung; Krousgrill, Charles M.; Sadeghi, Farshid

    2008-09-01

    The mathematical formulation for determining the dynamic instability due to transverse doublet modes in the self-excited vibration of a thin annular plate is presented in this paper. An analytical approach is developed to obtain the stability results from the eigenvalue problem of a stationary disc with a finite contact area. The approach uses the eigenfunctions of transverse doublet modes in classical plate theory and establishes the formulation of modal instability due to the modal-interaction of a doublet mode pair. The one-doublet mode model of a disc and a discrete model equivalent to the one-doublet mode model are proposed for providing a more fundamental understanding of the onset of squeal. The analytical models are validated through a comparison of results from a modal expansion model obtained from finite element component models. Throughout the analytical investigation, the pad arc length is found to be a critical design parameter in controlling squeal propensity.

  8. Equivalent circuit modeling of a piezo-patch energy harvester on a thin plate with AC-DC conversion

    Science.gov (United States)

    Bayik, B.; Aghakhani, A.; Basdogan, I.; Erturk, A.

    2016-05-01

    As an alternative to beam-like structures, piezoelectric patch-based energy harvesters attached to thin plates can be readily integrated to plate-like structures in automotive, marine, and aerospace applications, in order to directly exploit structural vibration modes of the host system without mass loading and volumetric occupancy of cantilever attachments. In this paper, a multi-mode equivalent circuit model of a piezo-patch energy harvester integrated to a thin plate is developed and coupled with a standard AC-DC conversion circuit. Equivalent circuit parameters are obtained in two different ways: (1) from the modal analysis solution of a distributed-parameter analytical model and (2) from the finite-element numerical model of the harvester by accounting for two-way coupling. After the analytical modeling effort, multi-mode equivalent circuit representation of the harvester is obtained via electronic circuit simulation software SPICE. Using the SPICE software, electromechanical response of the piezoelectric energy harvester connected to linear and nonlinear circuit elements are computed. Simulation results are validated for the standard AC-AC and AC-DC configurations. For the AC input-AC output problem, voltage frequency response functions are calculated for various resistive loads, and they show excellent agreement with modal analysis-based analytical closed-form solution and with the finite-element model. For the standard ideal AC input-DC output case, a full-wave rectifier and a smoothing capacitor are added to the harvester circuit for conversion of the AC voltage to a stable DC voltage, which is also validated against an existing solution by treating the single-mode plate dynamics as a single-degree-of-freedom system.

  9. Thermal transport across a substrate-thin-film interface: effects of film thickness and surface roughness.

    Science.gov (United States)

    Liang, Zhi; Sasikumar, Kiran; Keblinski, Pawel

    2014-08-08

    Using molecular dynamics simulations and a model AlN-GaN interface, we demonstrate that the interfacial thermal resistance R(K) (Kapitza resistance) between a substrate and thin film depends on the thickness of the film and the film surface roughness when the phonon mean free path is larger than film thickness. In particular, when the film (external) surface is atomistically smooth, phonons transmitted from the substrate can travel ballistically in the thin film, be scattered specularly at the surface, and return to the substrate without energy transfer. If the external surface scatters phonons diffusely, which is characteristic of rough surfaces, R(K) is independent of film thickness and is the same as R(K) that characterizes smooth surfaces in the limit of large film thickness. At interfaces where phonon transmission coefficients are low, the thickness dependence is greatly diminished regardless of the nature of surface scattering. The film thickness dependence of R(K) is analogous to the well-known fact of lateral thermal conductivity thickness dependence in thin films. The difference is that phonon-boundary scattering lowers the in-plane thermal transport in thin films, but it facilitates thermal transport from the substrate to the thin film.

  10. The Effect of Thermal Annealing Processes on Structural and Photoluminescence of Zinc Oxide Thin Film

    Directory of Open Access Journals (Sweden)

    Huai-Shan Chin

    2013-01-01

    Full Text Available This study used radio frequency sputtering at room temperature to prepare a zinc oxide (ZnO thin film. After deposition, the thin film was placed in a high-temperature furnace to undergo thermal annealing at different temperatures (300, 400, 500, and 600°C and for different dwelling times (15, 30, 45, and 60 min. The objective was to explore the effects that the described process had on the thin film’s internal structure and luminescence properties. A scanning electron microscope topographic image showed that the size of the ZnO crystals grew with increases in either the thermal annealing temperature or the dwelling time. However, significant differences in the levels of influence caused by increasing the thermal annealing temperature or dwelling time existed; the thermal annealing temperature had a greater effect on crystal growth when compared to the dwelling time. Furthermore, the crystallization directions of ZnO (002, (101, (102, and (103 can be clearly observed through an X-ray diffraction analysis, and crystallization strength increased with an increase in the thermal annealing temperature. The photoluminescence measurement spectra showed that ultraviolet (UV emission intensity increased with increases in thermal annealing temperature and dwelling time. However, when the thermal annealing temperature reached 600°C or when the dwelling time reached 60 min, even exhibited a weak green light emission peak.

  11. Experimental Investigation of Zinc Antimonide Thin Films under Different Thermal Boundary Conditions

    DEFF Research Database (Denmark)

    Mir Hosseini, Seyed Mojtaba; Rosendahl, Lasse Aistrup; Rezaniakolaei, Alireza

    for all cases, showing that the electrical potential difference is increasing by temperature for all cases with the same slope. Also the value of Seebeck coefficient (α) is almost constant for all cases. The obtained value of α can compete with developed bulk TEG materials in literature. The thin film...... is able to operate in relatively high range of temperature with long working period without failure. Furthermore, effects of implementing thermal cycling on stability analysis of a TEG sample are considered. By testing the thermoelectric thin film specimen during a thermal cycling, behavior of the TEG...

  12. Titer plate formatted continuous flow thermal reactors for high throughput applications: fabrication and testing

    Science.gov (United States)

    Sang-Won Park, Daniel; Chen, Pin-Chuan; You, Byoung Hee; Kim, Namwon; Park, Taehyun; Lee, Tae Yoon; Datta, Proyag; Desta, Yohannes; Soper, Steven A.; Nikitopoulos, Dimitris E.; Murphy, Michael C.

    2010-05-01

    A high throughput, multi-well (96) polymerase chain reaction (PCR) platform, based on a continuous flow (CF) mode of operation, was developed. Each CFPCR device was confined to a footprint of 8 × 8 mm2, matching the footprint of a well on a standard micro-titer plate. While several CFPCR devices have been demonstrated, this is the first example of a high-throughput multi-well continuous flow thermal reactor configuration. Verification of the feasibility of the multi-well CFPCR device was carried out at each stage of development from manufacturing to demonstrating sample amplification. The multi-well CFPCR devices were fabricated by micro-replication in polymers, polycarbonate to accommodate the peak temperatures during thermal cycling in this case, using double-sided hot embossing. One side of the substrate contained the thermal reactors and the opposite side was patterned with structures to enhance thermal isolation of the closely packed constant temperature zones. A 99 bp target from a λ-DNA template was successfully amplified in a prototype multi-well CFPCR device with a total reaction time as low as ~5 min at a flow velocity of 3 mm s-1 (15.3 s cycle-1) and a relatively low amplification efficiency compared to a bench-top thermal cycler for a 20-cycle device; reducing the flow velocity to 1 mm s-1 (46.2 s cycle-1) gave a seven-fold improvement in amplification efficiency. Amplification efficiencies increased at all flow velocities for 25-cycle devices with the same configuration.

  13. Tuning the Anisotropy of In-Plane Thermal Conduction in Thin Films by Modulating Thickness

    Science.gov (United States)

    Zeng, Yuqiang; Marconnet, Amy

    2018-01-01

    Anisotropy in thermal conductivity is promising for directing the heat-flow pathways in modern applications including thermal management of electronic devices. While some materials, like graphite, have strong anisotropy when comparing the in-plane thermal conductivity to cross-plane thermal conductivity, few naturally occurring materials have significant anisotropy within the in-plane directions, with an anisotropy ratio of ˜3 in few-layer black phosphorus being among the highest. In this Letter, we propose to control the thermal-conduction anisotropy by periodically modulating the thickness of thin films. Specifically, we model the thermal conduction in silicon-based thickness-modulated films using full three-dimensional simulations based on the phonon frequency-dependent Boltzmann transport equation. Our simulations demonstrate that phonon scattering with appropriately sized and shaped thickness-modulation features leads to a significant anisotropy in thermal conduction. In the diffusive regime, the same types of features lead to relatively low anisotropy (as calculated using the conventional heat diffusion equation). Thus, the enhanced thermal-conduction anisotropy with small features comes from the phonon scattering and size effects. Modulating the thickness of the thin films allows tuning the thermal-anisotropy ratio across an order of magnitude. Moreover, the proposed structures can be fabricated with currently available silicon-based nanofabrication techniques, without the need for exotic or expensive materials.

  14. Optimization of thermal performance of a smooth flat-plate solar air heater using teaching–learning-based optimization algorithm

    Directory of Open Access Journals (Sweden)

    R. Venkata Rao

    2015-12-01

    Full Text Available This paper presents the performance of teaching–learning-based optimization (TLBO algorithm to obtain the optimum set of design and operating parameters for a smooth flat plate solar air heater (SFPSAH. The TLBO algorithm is a recently proposed population-based algorithm, which simulates the teaching–learning process of the classroom. Maximization of thermal efficiency is considered as an objective function for the thermal performance of SFPSAH. The number of glass plates, irradiance, and the Reynolds number are considered as the design parameters and wind velocity, tilt angle, ambient temperature, and emissivity of the plate are considered as the operating parameters to obtain the thermal performance of the SFPSAH using the TLBO algorithm. The computational results have shown that the TLBO algorithm is better or competitive to other optimization algorithms recently reported in the literature for the considered problem.

  15. Analysis technology in the thick plate free drop impact, heat and thermal stress of the cask for radioactive material transport

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Dew Hey [Korea Institute of Nuclear and Safety, Taejon (Korea, Republic of); Lee, Young Shin; Ryu, Chung Hyun; Kim, Hyun Su; Choi, Kyung Joo; Choi, Young Jin; Lee, Jae Hyung; Na, Jae Yun; Kim, Seong Jong [Chungnam National Univ., Taejon (Korea, Republic of)

    2002-03-15

    In this study, The regulatory condition and analysis condition is analyzed for thick plate free drop, heat and thermal stress analysis to develop the safety assessment technology. Analysis is performed with finite element method which is one of the many analysis methods of the shipping cask. ANSYS, LS-DYNA3D and ABAQUS is suitable for thick plate free drop, heat and thermal stress analysis of the shipping cask. For the analysis model, the KSC-4 that is the shipping cask to transport spent nuclear fuel is investigated. The results of both LS-DYNA3D and ABAQUS for thick plate free drop and the results of ANSYS, LS-DYNA3D and ABAQUS for heat and thermal stress analysis is completely corresponded. And the integrity of the shipping cask is verified. Using this study, the reliable safety assessment technology is supplied to the staff. The efficient and reliable regulatory tasks is performed using the standard safety assessment technology.

  16. 3D COMSOL Simulations for Thermal Deflection of HFIR Fuel Plate in the "Cheverton-Kelley" Experiments

    Energy Technology Data Exchange (ETDEWEB)

    Jain, Prashant K [ORNL; Freels, James D [ORNL; Cook, David Howard [ORNL

    2012-08-01

    Three dimensional simulation capabilities are currently being developed at Oak Ridge National Laboratory using COMSOL Multiphysics, a finite element modeling software, to investigate thermal expansion of High Flux Isotope Reactor (HFIR) s low enriched uranium fuel plates. To validate simulations, 3D models have also been developed for the experimental setup used by Cheverton and Kelley in 1968 to investigate the buckling and thermal deflections of HFIR s highly enriched uranium fuel plates. Results for several simulations are presented in this report, and comparisons with the experimental data are provided when data are available. A close agreement between the simulation results and experimental findings demonstrates that the COMSOL simulations are able to capture the thermal expansion physics accurately and that COMSOL could be deployed as a predictive tool for more advanced computations at realistic HFIR conditions to study temperature-induced fuel plate deflection behavior.

  17. Improved Thermal-Vacuum Compatible Flat Plate Radiometric Source For System-Level Testing Of Optical Sensors

    Science.gov (United States)

    Schwarz, Mark A.; Kent, Craig J.; Bousquet, Robert; Brown, Steven W.

    2016-01-01

    In this work, we describe an improved thermal-vacuum compatible flat plate radiometric source which has been developed and utilized for the characterization and calibration of remote optical sensors. This source is unique in that it can be used in situ, in both ambient and thermal-vacuum environments, allowing it to follow the sensor throughout its testing cycle. The performance of the original flat plate radiometric source was presented at the 2009 SPIE1. Following the original efforts, design upgrades were incorporated into the source to improve both radiometric throughput and uniformity. The pre-thermal-vacuum (pre-TVAC) testing results of a spacecraft-level optical sensor with the improved flat plate illumination source, both in ambient and vacuum environments, are presented. We also briefly discuss potential FPI configuration changes in order to improve its radiometric performance.

  18. The Temperature Condition of the Plate with Temperature-Dependent Thermal Conductivity and Energy Release

    Directory of Open Access Journals (Sweden)

    V. S. Zarubin

    2016-01-01

    nonlinear mathematical model of the heat conductivity process in the volume power release body. Quantitative analysis of these models requires using the numerical methods, as a rule.At the same time, such a simple body, which is an unlimited plate of the constant thickness allows us, under certain assumptions, to solve analatically a nonlinear heat conductivity problem taking into account  the thermal conductivity of the plate material and the power release intensity versus temperature.This solution enables us to reveal a number of significant effects that have impact on the thermal state of the plate, including those related to conditions of available steady temperature distribution, and it can be used to test the results obtained by numerical methods.

  19. Thermal property measurement of thin fibers by complementary methods

    Science.gov (United States)

    Munro, Troy Robert

    To improve measurement reliability and repeatability and resolve the orders of magnitude discrepancy between the two different measurements (via reduced model transient electrothermal and lock-in IR thermography), this dissertation details the development of three complementary methods to accurately measure the thermal properties of the natural and synthetic Nephila (N.) clavipes spider dragline fibers. The thermal conductivity and diffusivity of the dragline silk of the (N.) clavipes spider has been characterized by one research group to be 151-416 W m-1 K-1 and 6.4-12.3 x 10-5 m2 s -1, respectively, for samples with low to high strains (zero to 19.7%). Thermal diffusivity of the dragline silk of a different spider species, Araneus diadematus, has been determined by another research group as 2 x 10-7 m2 s-1 for un-stretched silk. This dissertation seeks to resolve this discrepancy by three complementary methods. The methods detailed are the transient electrothermal technique (in both reduced and full model versions), the 3o method (for both current and voltage sources), and the non-contact, photothermal, quantum-dot spectral shape-based fluorescence thermometry method. These methods were also validated with electrically conductive and non-conductive fibers. The resulting thermal conductivity of the dragline silk is 1.2 W m-1 K-1, the thermal diffusivity is 6 x 10-7 m2 s -1 and the volumetric heat capacity is 2000 kJ m-3 K-1, with an uncertainty of about 12% for each property.

  20. RGB Color Calibration for Quantitative Image Analysis: The “3D Thin-Plate Spline” Warping Approach

    Directory of Open Access Journals (Sweden)

    Corrado Costa

    2012-05-01

    Full Text Available In the last years the need to numerically define color by its coordinates in n-dimensional space has increased strongly. Colorimetric calibration is fundamental in food processing and other biological disciplines to quantitatively compare samples’ color during workflow with many devices. Several software programmes are available to perform standardized colorimetric procedures, but they are often too imprecise for scientific purposes. In this study, we applied the Thin-Plate Spline interpolation algorithm to calibrate colours in sRGB space (the corresponding Matlab code is reported in the Appendix. This was compared with other two approaches. The first is based on a commercial calibration system (ProfileMaker and the second on a Partial Least Square analysis. Moreover, to explore device variability and resolution two different cameras were adopted and for each sensor, three consecutive pictures were acquired under four different light conditions. According to our results, the Thin-Plate Spline approach reported a very high efficiency of calibration allowing the possibility to create a revolution in the in-field applicative context of colour quantification not only in food sciences, but also in other biological disciplines. These results are of great importance for scientific color evaluation when lighting conditions are not controlled. Moreover, it allows the use of low cost instruments while still returning scientifically sound quantitative data.

  1. Transient Thermal Analysis of Intense Proton Beam Loss on a Kicker Magnet Conductor Plate

    CERN Document Server

    Knaus, P

    2000-01-01

    The Super Proton Synchrotron SPS will be used as injector for the Large Hadron Collider LHC and needs adaptation to meet LHC requirements. The SPS injection kicker magnets MKP will undergo important modifications to comply with the requirements on magnetic field rise-time and ripple. The injection kicker presently installed has a return conductor of beryllium to minimise the risk of metal evaporation from its surface due to heating caused by beam impact. In the context of refurbishing the MKP to satisfy LHC requirements these conductors need replacement, preferably with a less delicate material. This article presents the transient thermal analysis of energy deposition caused by beam loss on the conductor plate. The expected time structure of the beam is taken into account. Simulations comparing different conductor materials have been performed, leading to the result that a significantly cheaper and fully inoffensive titanium alloy can satisfy the needs.

  2. Fabrication of thermally evaporated Al thin film on cylindrical PET monofilament for wearable computing devices

    Science.gov (United States)

    Liu, Yang; Kim, Eunju; Han, Jeong In

    2016-01-01

    During the initial development of wearable computing devices, the conductive fibers of Al thin film on cylindrical PET monofilament were fabricated by thermal evaporation. Their electrical current-voltage characteristics curves were excellent for incorporation into wearable devices such as fiber-based cylindrical capacitors or thin film transistors. Their surfaces were modified by UV exposure and dip coating of acryl or PVP to investigate the surface effect. The conductive fiber with PVP coating showed the best conductivities because the rough surface of the PET substrate transformed into a smooth surface. The conductivities of PET fiber with and without PVP were 6.81 × 103 Ω-1cm-1 and 5.62 × 103 Ω-1cm-1, respectively. In order to understand the deposition process of Al thin film on cylindrical PET, Al thin film on PET fiber was studied using SEM (Scanning Electron Microscope), conductivities and thickness measurements. Hillocks on the surface of conductive PET fibers were observed and investigated by AFM on the surface. Hillocks were formed and grown during Al thermal evaporation because of severe compressive strain and plastic deformation induced by large differences in thermal expansion between PET substrate and Al thin film. From the analysis of hillock size distribution, it turns out that hillocks grew not transversely but longitudinally. [Figure not available: see fulltext.

  3. Efficient extraction of thin-film thermal parameters from numerical models via parametric model order reduction

    NARCIS (Netherlands)

    Bechtold, T.; Hohlfeld, D.; Rudnyi, E.B.; Günther, M.

    2010-01-01

    In this paper we present a novel highly efficient approach to determine material properties from measurement results. We apply our method to thermal properties of thin-film multilayers with three different materials, amorphous silicon, silicon nitride and silicon oxide. The individual material

  4. Thin-film ‘Thermal Well’ Emitters and Absorbers for High-Efficiency Thermophotovoltaics

    Science.gov (United States)

    Tong, Jonathan K.; Hsu, Wei-Chun; Huang, Yi; Boriskina, Svetlana V.; Chen, Gang

    2015-01-01

    A new approach is introduced to significantly improve the performance of thermophotovoltaic (TPV) systems using low-dimensional thermal emitters and photovoltaic (PV) cells. By reducing the thickness of both the emitter and the PV cell, strong spectral selectivity in thermal emission and absorption can be achieved by confining photons in trapped waveguide modes inside the thin-films that act as thermal analogs to quantum wells. Simultaneously, photo-excited carriers travel shorter distances across the thin-films reducing bulk recombination losses resulting in a lower saturation current in the PV cell. We predict a TPV efficiency enhancement with near-field coupling between the thermal emitter and the PV cell up to 38.7% using a thin-film germanium (Ge) emitter at 1000 K and an ultra-thin gallium antimonide (GaSb) cell supported by perfect back reflectors separated by 100 nm. Even in the far-field limit, the efficiency is predicted to reach 31.5%, which is over an order of magnitude higher than the Shockley Queisser limit of 1.6% for a bulk GaSb cell and a blackbody emitter at 1000 K. The proposed design approach does not require nanoscale patterning of the emitter and PV cell surfaces, but instead offers a simple low-cost solution to improve the performance of thermophotovoltaic systems. PMID:26030711

  5. Thin-film 'Thermal Well' Emitters and Absorbers for High-Efficiency Thermophotovoltaics.

    Science.gov (United States)

    Tong, Jonathan K; Hsu, Wei-Chun; Huang, Yi; Boriskina, Svetlana V; Chen, Gang

    2015-06-01

    A new approach is introduced to significantly improve the performance of thermophotovoltaic (TPV) systems using low-dimensional thermal emitters and photovoltaic (PV) cells. By reducing the thickness of both the emitter and the PV cell, strong spectral selectivity in thermal emission and absorption can be achieved by confining photons in trapped waveguide modes inside the thin-films that act as thermal analogs to quantum wells. Simultaneously, photo-excited carriers travel shorter distances across the thin-films reducing bulk recombination losses resulting in a lower saturation current in the PV cell. We predict a TPV efficiency enhancement with near-field coupling between the thermal emitter and the PV cell up to 38.7% using a thin-film germanium (Ge) emitter at 1000 K and an ultra-thin gallium antimonide (GaSb) cell supported by perfect back reflectors separated by 100 nm. Even in the far-field limit, the efficiency is predicted to reach 31.5%, which is over an order of magnitude higher than the Shockley Queisser limit of 1.6% for a bulk GaSb cell and a blackbody emitter at 1000 K. The proposed design approach does not require nanoscale patterning of the emitter and PV cell surfaces, but instead offers a simple low-cost solution to improve the performance of thermophotovoltaic systems.

  6. Thermal transport in Cu{sub 2}ZnSnS{sub 4} thin films

    Energy Technology Data Exchange (ETDEWEB)

    Thompson, W. D., E-mail: wthomps1@binghamton.edu; White, B. E. [Department of Physics, Binghamton University, 4400 Vestal Parkway East, Binghamton, New York 13902 (United States); Nandur, Abhishek [Materials Science and Engineering Program, Binghamton University, 4400 Vestal Parkway East, Binghamton, New York 13902 (United States)

    2016-03-07

    The stability of kesterite Cu{sub 2}ZnSnS{sub 4} (CZTS) under a range of compositions leads to the formation of a number of stable defects that appear to be necessary for high efficiency photovoltaic applications. In this work, the impact of the presence of these defects on the thermal conductivity of CZTS thin films has been explored. Thermal conductivities of CZTS thin films, prepared by pulsed laser deposition with differing compositions, were measured from 80 K to room temperature using the 3ω-method. The temperature dependence of the thermal conductivity indicates that the phonon mean free path is limited by strain field induced point defect scattering from sulfur vacancies in sulfur deficient thin films. The sulfurization of these films in a 10% N{sub 2} + H{sub 2}S ambient at 500 °C increased the sulfur content of the films, reducing the concentration of sulfur vacancies, and produced a negligible change in grain size with an unexpected factor of 5 increase in phonon boundary scattering. This, along with anisotropies in the x-ray diffraction peak profiles of the sulfurized films, suggests that the phonon mean free path in sulfurized films is limited by the presence of cation exchange induced stacking faults. The resulting room temperature thermal conductivities for sulfurized and sulfur deficient thin films were found to be 4.0 W/m K and 0.9 W/m K, respectively.

  7. Design, Construction, and Performance Analysis of a Wood Thermal Conductivity Measurement Device using Flat Plate Heat Pipes

    Directory of Open Access Journals (Sweden)

    Rasouli Moien

    2011-12-01

    Full Text Available In this paper, the design, construction, and performance analysis of a wood thermal conductivity measurement device using flat plate heat pipes has been experimentally studied. The device was designed to measure the thermal conductivity of wood in various ranges of temperature. Thermal conductivity of hornbeam (Carpinus betulus has been measured at various temperatures between 40-80 ºC and a relationship has been recommended for the sample. The results show that the thermal conductivity of this species increases linearly with temperature. Also, it has been concluded that flat plate heat pipes distribute heat flux on the surface of the wood uniformly leading to a faster steady state condition, which can reduce time of the test and result in energy saving and more accurate results.

  8. Neutronic and thermal-hydraulic analysis of fission molybdenum-99 production at Tehran Research Reactor using LEU plate targets.

    Science.gov (United States)

    Abedi, Ebrahim; Ebrahimkhani, Marzieh; Davari, Amin; Mirvakili, Seyed Mohammad; Tabasi, Mohsen; Maragheh, Mohammad Ghannadi

    2016-12-01

    Efficient and safe production of molybdenum-99 ( 99 Mo) radiopharmaceutical at Tehran Research Reactor (TRR) via fission of LEU targets is studied. Neutronic calculations are performed to evaluate produced 99 Mo activity, core neutronic safety parameters and also the power deposition values in target plates during a 7 days irradiation interval. Thermal-hydraulic analysis has been also carried out to obtain thermal behavior of these plates. Using Thermal-hydraulic analysis, it can be concluded that the safety parameters are satisfied in the current study. Consequently, the present neutronic and thermal-hydraulic calculations show efficient 99 Mo production is accessible at significant activity values in TRR current core configuration. Copyright © 2016 Elsevier Ltd. All rights reserved.

  9. Thermal Analysis Of Cover Plate Of Galvanizing Bath Tub At Bridge amp Roof Co. I Ltd. By Shape Modification

    Directory of Open Access Journals (Sweden)

    Anirban Jana

    2015-08-01

    Full Text Available This project is aimed for thermally analyzing stress and strain on cover plate of galvanizing bath tub at Bridge amp Roof co. I Ltd in order to maintain 450C in bath tub. Along with analysis part cover plate shape was modified due to its continuous use amp prevailing conditions at the workshop. The cover plate consist of insulating materials compacted to retain the heat in the bath tub. The thermal convection of air is less than thermal resistance of insulating materials used thus heat loss is negligible. Thermal convection air 0.0579 w m k Thermal Resistance Insulator 7.046 w m k. Thermal analysis report show at 450C. Deformation is effecting end portion 2-3 mm. Stress amp Strain at that portion is also low 0.1-0.3 Mpa. Heat transfer of air is more than insulating materials. Thus Heat transfer rate of Insulating materials being low they dont conduct heat from the bath tub to the atmosphere. So temperature of the bath tub is maintained. QA 1806.25 W Heat transfer rate of Air by convection QI 270.43 W Heat transfer rate of Insulation materials

  10. Laminar thermally developing flow in rectangular channels and parallel plates: uniform heat flux

    Science.gov (United States)

    Smith, Andrew N.; Nochetto, Horacio

    2014-05-01

    Numerical simulations were conducted for thermally developing laminar flow in rectangular channels with aspect ratios ranging from 1 to 100, and for parallel plates. The simulations were for laminar, thermally developing flow with H1 boundary conditions: uniform heat flux along the length of the channel and constant temperature around the perimeter. In the limit as the non-dimensional length, x* = x/(D h RePr), goes to zero, the Nusselt number is dependent on x* to the negative exponent m. As the non-dimensional length goes to infinity the Nusselt number approaches fully developed values that are independent of x*. General correlations for the local and mean heat transfer coefficients are presented that use an asymptotic blending function to transition between these limiting cases. The discrepancy between the correlation and the numerical results is less than 2.5 % for all aspect ratios. The correlations presented are applicable to all aspect ratios and all non-dimensional lengths, and decrease the discrepancy relative to existing correlations.

  11. The effects of the overriding plate thermal state on the slab dip in an ocean-continent subduction system

    CERN Document Server

    Roda, Manuel; Spalla, Maria Iole; 10.1016/j.crte.2011.01.005

    2011-01-01

    To evaluate the effects of variations in the thermal state of the overriding plate on the slab dip in an ocean-continent subduction system, a 2-D finite element thermo-mechanical model was implemented. The lithosphere base was located at the depth of the 1600 K isotherm. Numerical simulations were performed while taking into account four different initial thicknesses for the oceanic lithosphere (60, 80, 95 and 110 km) and five different thicknesses of the overriding plate, as compared in terms of the continental-oceanic plate thickness ratio (100, 120, 140, 160 and 200% of the oceanic lithosphere thickness). The results of numerical modeling indicate that a high variability of the subducting plate geometry occurs for an oceanic lithosphere thickness ranging from 60 to 80 km, while the variability decreases where the oceanic plates are thicker (95 and 110 km). Furthermore, the slab dip strongly depends on the thermal state of the overriding plate, and, in particular, the slab dip decreases with the increase in...

  12. Three-dimensional solutions for the free vibrations and buckling of thermally stressed multilayered angle-ply composite plates

    Science.gov (United States)

    Noor, Ahmed K.; Burton, W. S.

    1992-01-01

    Analytic three-dimensional elasticity solutions are developed for the free vibration and buckling of thermally stressed rectangular multilayered angle-ply anisotropic plates which are assumed to have an antisymmetric lamination with respect to the middle plane. Sensitivity derivatives are evaluated and used to investigate the sensitivity of the vibration and buckling responses to variations in the different lamination and material parameters of the plate. A Duhamel-Neumann-type constitutive model is used, and the material properties are assumed to be independent of temperature. Numerical results are presented, showing the effects of variations in the material characteristics and fiber orientation of different layers, as well as the effect of initial thermal deformation on the vibrational and buckling responses of the plate.

  13. Numerically modeling Brownian thermal noise in amorphous and crystalline thin coatings

    Science.gov (United States)

    Lovelace, Geoffrey; Demos, Nicholas; Khan, Haroon

    2018-01-01

    Thermal noise is expected to be one of the noise sources limiting the astrophysical reach of Advanced LIGO (once commissioning is complete) and third-generation detectors. Adopting crystalline materials for thin, reflecting mirror coatings, rather than the amorphous coatings used in current-generation detectors, could potentially reduce thermal noise. Understanding and reducing thermal noise requires accurate theoretical models, but modeling thermal noise analytically is especially challenging with crystalline materials. Thermal noise models typically rely on the fluctuation-dissipation theorem, which relates the power spectral density of the thermal noise to an auxiliary elastic problem. In this paper, we present results from a new, open-source tool that numerically solves the auxiliary elastic problem to compute the Brownian thermal noise for both amorphous and crystalline coatings. We employ the open-source deal.ii and PETSc frameworks to solve the auxiliary elastic problem using a finite-element method, adaptive mesh refinement, and parallel processing that enables us to use high resolutions capable of resolving the thin reflective coating. We verify numerical convergence, and by running on up to hundreds of compute cores, we resolve the coating elastic energy in the auxiliary problem to approximately 0.1%. We compare with approximate analytic solutions for amorphous materials, and we verify that our solutions scale as expected with changing beam size, mirror dimensions, and coating thickness. Finally, we model the crystalline coating thermal noise in an experiment reported by Cole et al (2013 Nat. Photon. 7 644–50), comparing our results to a simpler numerical calculation that treats the coating as an ‘effectively amorphous’ material. We find that treating the coating as a cubic crystal instead of as an effectively amorphous material increases the thermal noise by about 3%. Our results are a step toward better understanding and reducing thermal noise to

  14. Thermal resistances of crystalline and amorphous few-layer oxide thin films

    Science.gov (United States)

    Chen, Liang; Kumari, Niru; Hou, Yu

    2017-11-01

    Thermal insulation at nanoscale is of crucial importance for non-volatile memory devices such as phase change memory and memristors. We perform non-equilibrium molecular dynamics simulations to study the effects of interface materials and structures on thermal transport across the few-layer dielectric nanostructures. The thermal resistance across few-layer nanostructures and thermal boundary resistance at interfaces consisting of SiO2/HfO2, SiO2/ZrO2 or SiO2/Al2O3 are obtained for both the crystalline and amorphous structures. Based on the comparison temperature profiles and phonon density of states, we show that the thermal boundary resistances are much larger in crystalline few-layer oxides than the amorphous ones due to the mismatch of phonon density of state between distinct oxide layers. Compared with the bulk SiO2, the increase of thermal resistance across crystalline few-layer oxides results from the thermal boundary resistance while the increase of thermal resistance across amorphous few-layer oxides is attributed to the lower thermal conductivity of the amorphous thin films.

  15. Recent Advances in AC-DC Transfer Measurements Using Thin-Film Thermal Converters

    Energy Technology Data Exchange (ETDEWEB)

    WUNSCH,THOMAS F.; KINARD,JOSEPH R.; MANGINELL,RONALD P.; LIPE,THOMAS E.; SOLOMON JR.,OTIS M.; JUNGLING,KENNETH C.

    2000-12-08

    New standards for ac current and voltage measurements, thin-film multifunction thermal converters (MJTCS), have been fabricated using thin-film and micro-electro-mechanical systems (MEMS) technology. Improved sensitivity and accuracy over single-junction thermoelements and targeted performance will allow new measurement approaches in traditionally troublesome areas such as the low frequency and high current regimes. A review is presented of new microfabrication techniques and packaging methods that have resulted from a collaborative effort at Sandia National Laboratories and the National Institute of Standards and Technology (MHZ).

  16. Determination of dispersion parameters of thermally deposited CdTe thin film

    Energy Technology Data Exchange (ETDEWEB)

    Dhimmar, J. M., E-mail: bharatpmodi@gmail.com; Desai, H. N.; Modi, B. P. [Department of Physics, Veer Narmad South Gujarat University, Surat, Gujarat (India)

    2016-05-23

    Cadmium Telluride (CdTe) thin film was deposited onto glass substrates under a vacuum of 5 × 10{sup −6} torr by using thermal evaporation technique. The prepared film was characterized for dispersion analysis from reflectance spectra within the wavelength range of 300 nm – 1100 nm which was recorded by using UV-Visible spectrophotometer. The dispersion parameters (oscillator strength, oscillator wavelength, high frequency dielectric constant, long wavelength refractive index, lattice dielectric constant and plasma resonance frequency) of CdTe thin film were investigated using single sellimeir oscillator model.

  17. Structural, thermal and magnetic properties of Pr-123 polycrystalline and thin film superconductors

    Energy Technology Data Exchange (ETDEWEB)

    Araujo-Moreira, F.M. E-mail: faraujo@df.ufscar.br; Lisboa-Filho, P.N.; Lanfredi, A.J.C.; Ortiz, W.A.; Zanetti, S.M.; Leite, E.R.; Mombru, A.W.; Ghivelder, L.; Zhao, Y.G.; Venkatesan, V

    2001-05-01

    We report the structural, thermal and magnetic properties of superconducting PrBa{sub 2}Cu{sub 3}O{sub 7-{delta}} (Pr-123). The existence of superconductivity in samples of Pr-123 is still a polemic subject. To further study this problem, we have measured thin films and high-quality polycrystalline bulk samples by following a sol-gel method, associated with heat treatment in argon atmosphere. The present results confirm the occurrence of superconductivity in Pr-123 polycrystalline and thin film samples.

  18. On a model of oscillations of a thin flat plate with a variety of mounts on opposite sides

    Science.gov (United States)

    Kal'menov, Tynysbek; Iskakova, Ulzada

    2016-12-01

    In this paper we consider a model case of stationary vibrations of a thin flat plate, one side of which is embedded, the opposite side is free, and the sides are freely leaned. In mathematical modeling there is a local boundary value problem for the biharmonic equation in a rectangular domain. Boundary conditions are given on all boundary of the domain. We show that the considered problem is self-adjoint. Herewith the problem is ill-posed. We show that the stability of solution to the problem is disturbed. Necessary and sufficient conditions of existence of the problem solution are found. Spaces of the ill-posedness of the considered problem are constructed.

  19. Estimate of thermal fatigue lifetime for the INCONEL 625lCF plate while exposed to concentrated solar radiation

    Energy Technology Data Exchange (ETDEWEB)

    Rojas-Morin, A.; Fernandez-Reche, J.

    2011-07-01

    A system for testing the thermal cycling of materials and components has been developed and installed at the DISTAL-I parabolic dish facility located at the Plataforma Solar de Almeria (PSA) in Spain. This system allows us to perform abrupt heating/cooling tests by exposing central solar receiver materials to concentrated solar radiation. These tests are performed to simulate both the normal and critical operational conditions of the central solar receiver. The thermal fatigue life for the INCONEL 625LCF plate when subjected to concentrated solar radiation has been estimated with this system. We have also developed a numerical model that evaluates the thermal behavior of the plate material; additionally, the model yields the tensile-compressive stresses on the plate, which allow the estimation of the Stress-Life (S-N) fatigue curves. These curves show that the lifetime of the plate is within the High Cycle Fatigue (HCF) region at the operational temperatures of both 650 degree centigrade and 900 degree centigrade. (Author) 20 refs.

  20. 3D printed metamaterial design to focus wave energy in thin plates

    Science.gov (United States)

    Kabir, Minoo; Allen, Margaret G.; Ozevin, Didem

    2017-04-01

    Acoustic metamaterials are periodic and composite structures that can block, direct and strengthen propagating elastic waves. They are periodic elastic composites made of two or more materials with different elastic properties. The periodic structure can exhibit certain band gaps that are used to manipulate wave field. In this research, the periodic and composite structure is made of aluminum plate and rubber cylinders manufactured using 3D printing. The ability to block and redirect elastic waves is numerically and experimentally demonstrated. Wave field focusing reduces the wave attenuation, which allows increasing the distance of acoustic sensors for damage detection in large-scale structures.

  1. A Framework for Extension of Dynamic Finite Element Formulation to Flexural Vibration Analysis of Thin Plates

    Directory of Open Access Journals (Sweden)

    Mohammad M. Elahi

    2017-01-01

    Full Text Available Dynamic Finite Element formulation is a powerful technique that combines the accuracy of the exact analysis with wide applicability of the finite element method. The infinite dimensionality of the exact solution space of plate equation has been a major challenge for development of such elements for the dynamic analysis of flexible two-dimensional structures. In this research, a framework for such extension based on subset solutions is proposed. An example element is then developed and implemented in MATLAB® software for numerical testing, verification, and validation purposes. Although the presented formulation is not exact, the element exhibits good convergence characteristics and can be further enriched using the proposed framework.

  2. A New Approach for Studying Nonlinear Dynamic Response of a Thin Plate with Internal Resonance in a Fractional Viscoelastic Medium

    Directory of Open Access Journals (Sweden)

    Yury A. Rossikhin

    2015-01-01

    Full Text Available In the previous analysis, the dynamic behaviour of a nonlinear plate embedded into a fractional derivative viscoelastic medium has been studied by the method of multiple time scales under the conditions of the internal resonances two-to-one and one-to-one, as well as the internal combinational resonances for the case when the linear parts of nonlinear equations of motion occur to be coupled. A new approach proposed in this paper allows one to uncouple the linear parts of equations of motion of the plate, while the same method, the method of multiple time scales, has been utilized for solving nonlinear equations. The influence of viscosity on the energy exchange mechanism between interacting nonlinear modes has been analyzed. It has been shown that for some internal resonances there exist such particular cases when it is possible to obtain two first integrals, namely, the energy integral and the stream function, which allows one to reduce the problem to the calculation of elliptic integrals. The new approach enables one to solve the problems of vibrations of thin bodies more efficiently.

  3. Tuneable surface enhanced Raman spectroscopy hyphenated to chemically derivatized thin-layer chromatography plates for screening histamine in fish.

    Science.gov (United States)

    Xie, Zhengjun; Wang, Yang; Chen, Yisheng; Xu, Xueming; Jin, Zhengyu; Ding, Yunlian; Yang, Na; Wu, Fengfeng

    2017-09-01

    Reliable screening of histamine in fish was of urgent importance for food safety. This work presented a highly selective surface enhanced Raman spectroscopy (SERS) method mediated by thin-layer chromatography (TLC), which was tailored for identification and quantitation of histamine. Following separation and derivatization with fluram, plates were assayed with SERS, jointly using silver nanoparticle and NaCl. The latter dramatically suppressed the masking effect caused by excessive fluram throughout the plate, thus offering clear baseline and intensive Raman fingerprints specific to the analyte. Under optimized conditions, the usability of this method was validated by identifying the structural fingerprints of both targeted and unknown compounds in fish samples. Meanwhile, the quantitative results of this method agreed with those by an HPLC method officially suggested by EU for histamine determination. Showing remarkable cost-efficiency and user-friendliness, this facile TLC-SERS method was indeed screening-oriented and may be more attractive to controlling laboratories of limited resource. Copyright © 2017 Elsevier Ltd. All rights reserved.

  4. Biharmonic split ring resonator metamaterial: Artificially dispersive effective density in thin periodically perforated plates

    KAUST Repository

    Farhat, Mohamed

    2014-08-01

    We present in this paper a theoretical and numerical analysis of bending waves localized on the boundary of a platonic crystal whose building blocks are Split Ring Resonators (SRR). We first derive the homogenized parameters of the structured plate using a three-scale asymptotic expansion in the linearized biharmonic equation. In the limit when the wavelength of the bending wave is much larger than the typical heterogeneity size of the platonic crystal, we show that it behaves as an artificial plate with an anisotropic effective Young modulus and a dispersive effective mass density. We then analyze dispersion diagrams associated with bending waves propagating within an infinite array of SRR, for which eigen-solutions are sought in the form of Floquet-Bloch waves. We finally demonstrate that this structure displays the hallmarks of All-Angle Negative Refraction (AANR) and it leads to superlensing and ultrarefraction effects, interpreted thanks to our homogenization model as a consequence of negative and vanishing effective density, respectively. © EPLA, 2014.

  5. Natural Convection Flow of Fractional Nanofluids Over an Isothermal Vertical Plate with Thermal Radiation

    Directory of Open Access Journals (Sweden)

    Constantin Fetecau

    2017-03-01

    Full Text Available The studies of classical nanofluids are restricted to models described by partial differential equations of integer order, and the memory effects are ignored. Fractional nanofluids, modeled by differential equations with Caputo time derivatives, are able to describe the influence of memory on the nanofluid behavior. In the present paper, heat and mass transfer characteristics of two water-based fractional nanofluids, containing nanoparticles of CuO and Ag, over an infinite vertical plate with a uniform temperature and thermal radiation, are analytically and graphically studied. Closed form solutions are determined for the dimensionless temperature and velocity fields, and the corresponding Nusselt number and skin friction coefficient. These solutions, presented in equivalent forms in terms of the Wright function or its fractional derivatives, have also been reduced to the known solutions of ordinary nanofluids. The influence of the fractional parameter on the temperature, velocity, Nusselt number, and skin friction coefficient, is graphically underlined and discussed. The enhancement of heat transfer in the natural convection flows is lower for fractional nanofluids, in comparison to ordinary nanofluids. In both cases, the fluid temperature increases for increasing values of the nanoparticle volume fraction.

  6. A new model for thermal contact resistance between fuel cell gas diffusion layers and bipolar plates

    Science.gov (United States)

    Sadeghifar, Hamidreza; Djilali, Ned; Bahrami, Majid

    2014-11-01

    A new analytical model is developed to predict the thermal contact resistance (TCR) between fibrous porous media such as gas diffusion layers (GDLs) of polymer electrolyte membrane fuel cells (PEMFCs) and flat surfaces (bipolar plates). This robust model accounts for the salient geometrical parameters of GDLs, mechanical deformation, and thermophysical properties of the contacting bodies. The model is successfully validated against experimental data, and is used to perform in a comprehensive parametric study to investigate the effects of fiber parameters such as waviness and GDL properties on the TCR. Fiber waviness, diameter and surface curvature, as well as GDL porosity, are found to have a strong influence on TCR whereas fiber length does not affect the TCR when the porosity is kept constant. Such findings provide useful guidance for design and manufacturing of more effective GDLs for PEMFC heat management. The analytic model can be readily implemented in simulation and modeling of PEMFCs, and can be extended with minor modifications to other fibrous porous media such as fibrous catalysts, insulating media and sintered metals.

  7. A Dynamic Multinode Model for Component-Oriented Thermal Analysis of Flat-Plate Solar Collectors

    Directory of Open Access Journals (Sweden)

    Christoph N. Reiter

    2015-01-01

    Full Text Available A mathematical model of a flat-plate solar collector was developed on the basis of the physical principles of optics and heat transfer in order to determine collector’s component temperatures as well as collector efficiency. In contrast to many available models, the targeted use of this dynamic model is the detailed, theoretical investigation of the thermal behaviour of newly developed or adjusted collector designs on component level, for example, absorber, casing, or transparent cover. The defined model is based on a multinode network (absorber, fluid, glazing, and backside insulation containing the relevant physical equations to transfer the energy. The heat transfer network covers heat conduction, convection, and radiation. Furthermore, the collector optics is defined for the plane glazing and the absorber surface and also considers interactions between them. The model enables the variation of physical properties considering the geometric parameters and materials. Finally, the model was validated using measurement data and existing efficiency curve models. Both comparisons proved high accuracy of the developed model with deviation of up to 3% in collector efficiency and 1 K in component temperatures.

  8. Thermal-economic multi-objective optimization of plate fin heat exchanger using genetic algorithm

    Energy Technology Data Exchange (ETDEWEB)

    Sanaye, Sepehr; Hajabdollahi, Hassan [Energy Systems Improvement Laboratory (ESIL), Department of Mechanical Engineering, Iran University of Science and Technology (IUST) (Iran)

    2010-06-15

    Thermal modeling and optimal design of compact heat exchangers are presented in this paper. {epsilon}NTU method was applied to estimate the heat exchanger pressure drop and effectiveness. Fin pitch, fin height, fin offset length, cold stream flow length, no-flow length and hot stream flow length were considered as six design parameters. Fast and elitist non-dominated sorting genetic-algorithm (NSGA-II) was applied to obtain the maximum effectiveness and the minimum total annual cost (sum of investment and operation costs) as two objective functions. The results of optimal designs were a set of multiple optimum solutions, called 'Pareto optimal solutions'. The sensitivity analysis of change in optimum effectiveness and total annual cost with change in design parameters of the plate fin heat exchanger was also performed and the results are reported. As a short cut for choosing the system optimal design parameters the correlations between two objectives and six decision variables with acceptable precision were presented using artificial neural network analysis. (author)

  9. Procedure for Automated Eddy Current Crack Detection in Thin Titanium Plates

    Science.gov (United States)

    Wincheski, Russell A.

    2012-01-01

    This procedure provides the detailed instructions for conducting Eddy Current (EC) inspections of thin (5-30 mils) titanium membranes with thickness and material properties typical of the development of Ultra-Lightweight diaphragm Tanks Technology (ULTT). The inspection focuses on the detection of part-through, surface breaking fatigue cracks with depths between approximately 0.002" and 0.007" and aspect ratios (a/c) of 0.2-1.0 using an automated eddy current scanning and image processing technique.

  10. Toward a Characterization of the Debris Cloud Created in a Hypervelocity Impact on a Thin Plate

    Science.gov (United States)

    1993-08-01

    I.0) CALL DHOLE (TS,DP,RP,RT,LP,V,BHN,DH) MTARG-PI*(DH/2.0)*(DH/2.0)*TS*RT R-L22/TS IF (R.GE.1.0) FSR-I.0 IF (R.LT.1.0) ISR=R MSR-FSR*MTARG MUSM-MTARG... DHOLE (TS,DP,RP,RT,LP,V,BHN,DH) 4 IMPLICIT DOUBLE PRECISION (A-H,O-Z) 89 DOUBLE PRECISION K,LP C ....... THIS SUBROUTINE CALCULATES THE HOLE IN A THIN

  11. Growth and structure of thermally evaporated Bi{sub 2}Te{sub 3} thin films

    Energy Technology Data Exchange (ETDEWEB)

    Rogacheva, E.I., E-mail: rogacheva@kpi.kharkov.ua [National Technical University “Kharkov Polytechnic Institute”, 21 Frunze St., Kharkov 61002 (Ukraine); Budnik, A.V. [National Technical University “Kharkov Polytechnic Institute”, 21 Frunze St., Kharkov 61002 (Ukraine); Dobrotvorskaya, M.V.; Fedorov, A.G.; Krivonogov, S.I.; Mateychenko, P.V. [Institute for Single Crystals of NAS of Ukraine, 60 Lenin Prospect, Kharkov 61001 (Ukraine); Nashchekina, O.N.; Sipatov, A.Yu. [National Technical University “Kharkov Polytechnic Institute”, 21 Frunze St., Kharkov 61002 (Ukraine)

    2016-08-01

    The growth mechanism, microstructure, and crystal structure of the polycrystalline n-Bi{sub 2}Te{sub 3} thin films with thicknesses d = 15–350 nm, prepared by thermal evaporation in vacuum onto glass substrates, were studied. Bismuth telluride with Te excess was used as the initial material for the thin film preparation. The thin film characterization was performed using X-ray diffraction, X-ray photoelectron spectroscopy, energy-dispersive X-ray spectroscopy, scan electron microscopy, and electron force microscopy. It was established that the chemical composition of the prepared films corresponded rather well to the starting material composition and the films did not contain any phases apart from Bi{sub 2}Te{sub 3}. It was shown that the grain size and the film roughness increased with increasing film thickness. The preferential growth direction changed from [00l] to [015] under increasing d. The X-ray photoelectron spectroscopy studies showed that the thickness of the oxidized surface layer did not exceed 1.5–2.0 nm and practically did not change in the process of aging at room temperature, which is in agreement with the results reported earlier for single crystals. The obtained data show that using simple and inexpensive method of thermal evaporation in vacuum and appropriate technological parameters, one can grow n-Bi{sub 2}Te{sub 3} thin films of a sufficiently high quality. - Highlights: • The polycrystalline n-Bi{sub 2}Te{sub 3} thin films were grown thermal evaporation onto glass. • The growth mechanism and film structure were studied by different structure methods. • The grain size and film roughness increased with increasing film thickness. • The growth direction changes from [00l] to [015] under film thickness increasing. • The oxidized layer thickness (1–2 nm) did not change under aging at room temperature.

  12. Thermal and electrochemical durability of carbonaceous composites used as a bipolar plate of proton exchange membrane fuel cell

    Science.gov (United States)

    Kinumoto, Taro; Nagano, Keita; Tsumura, Tomoki; Toyoda, Masahiro

    Thermal and electrochemical durability of carbonaceous composite plates, which are made from graphite powders and a resin for use as bipolar plates of PEMFC (proton exchange membrane fuel cell), were investigated. The thermal durability was investigated by TG (thermal gravimetry) coupled with DTA (differential thermal analysis) technique under air up to 600 °C. A weight loss was significant over 300 °C, but the hydrophobicity was decreased after heated at 80 °C for 192 h. The electrochemical durability was investigated in 10 μmol dm -3 of hydrochloric acid solution under nitrogen or oxygen atmosphere by means of potential holding test from 0.8 to 1.5 V against RHE (reversible hydrogen electrode) at 80 °C. During the potential holding tests, CO 2 production due to the corrosion was quantified by a GC (gas-chromatography) and the production was detectable above 1.3 V irrespective with atmosphere; on the other hand, it was clarified from the contact angle measurements that the hydrophobicity was changed below 1.3 V. The results of this study showed that the carbonaceous composite plates were electrochemically degraded under PEMFC condition and were seriously degraded in URFC (unitized regenerative fuel cell) condition.

  13. COMBINED INFORMATION FROM RETARDATION FACTOR (RF) VALUES AND COLOR-REACTIONS ON THE PLATE GREATLY ENHANCES THE IDENTIFICATION POWER OF THIN-LAYER CHROMATOGRAPHY IN SYSTEMATIC TOXICOLOGICAL ANALYSIS

    NARCIS (Netherlands)

    HEGGE, HFJ; FRANKE, JP; DEZEEUW, RA

    A numerical color coding system has been developed to describe the colors of spots obtained after using location reagents in thin-layer chromatography (TLC). This system makes color reactions on the plate amenable to computer handling, so that the retardation factor (Rf) values plus color reactions

  14. Modification of microstructure and micromagnetic properties in Gd-Fe thin films by rapid thermal processing

    OpenAIRE

    Talapatraa, A.; Chelvane, J. Arout; Satpati, B.; Kumar, S.; Mohanty, J.

    2017-01-01

    Impact of rapid thermal processing (RTP) on microstructure and magnetic properties of Gd-Fe thin films have been investigated with a special emphasis to magnetic microstructure. 100 nm thick amorphous Gd-Fe film shows elongated stripe domains with characteristic feature size of 122 nm, which signifies the development of perpendicular magnetic anisotropy (PMA) in this system. RTP at 550^oC for different time intervals viz. 5, 10, 15, 20 minutes induces the crystallization of Fe over the amorph...

  15. APCVD hexagonal boron nitride thin films for passive near-junction thermal management of electronics

    Science.gov (United States)

    KC, Pratik; Rai, Amit; Ashton, Taylor S.; Moore, Arden L.

    2017-12-01

    The ability of graphene to serve as an ultrathin heat spreader has been previously demonstrated with impressive results. However, graphene is electrically conductive, making its use in contact with electronic devices problematic from a reliability and integration perspective. As an alternative, hexagonal boron nitride (h-BN) is a similarly structured material with large in-plane thermal conductivity but which possesses a wide band gap, thereby giving it potential to be utilized for directing contact, near-junction thermal management of electronics without shorting or the need for an insulating intermediate layer. In this work, the viability of using large area, continuous h-BN thin films as direct contact, near-junction heat spreaders for electronic devices is experimentally evaluated. Thin films of h-BN several square millimeters in size were synthesized via an atmospheric pressure chemical vapor deposition (APCVD) method that is both simple and scalable. These were subsequently transferred onto a microfabricated test device that simulated a multigate transistor while also allowing for measurements of the device temperature at various locations via precision resistance thermometry. Results showed that these large-area h-BN films with thicknesses of 77–125 nm are indeed capable of significantly lowering microdevice temperatures, with the best sample showing the presence of the h-BN thin film reduced the effective thermal resistance by 15.9% ± 4.6% compared to a bare microdevice at the same power density. Finally, finite element simulations of these experiments were utilized to estimate the thermal conductivity of the h-BN thin films and identify means by which further heat spreading performance gains could be attained.

  16. Dependence of electrical properties on thermal temperature in nanocrystalline SnO2 thin films.

    Science.gov (United States)

    Du, Juan; Zhang, HaiJiao; Jiao, Zheng; Wu, Minghong; Shek, Chan-Hung; Wu, C M Lawrence; Lai, Joseph K L; Chen, Zhiwen

    2011-12-01

    Nanocrystalline SnO2 thin films were prepared by pulsed laser deposition techniques on clean glass substrates, and the films were then annealed for 30 min from 50 to 550 degrees C with a step of 50 degrees C, respectively. The investigation of X-ray diffraction confirmed that the various SnO2 thin films were consisted of nanoparticles with average grain size in the range of 23.7-28.9 nm. Root-mean-square surface roughness of the as-prepared SnO2 thin film was measured to be 25.6 nm which decreases to 16.2 nm with thermal annealing. Electrical resistivity and refractive index were measured as a function of annealing temperature, and found to lie between 1.24 to 1.45 momega-cm, and 1.502 to 1.349, respectively. The results indicate that nearly opposite actions to root-mean-square surface roughness and electrical resistivity make a unique performance with thermal annealing temperature. The post annealing shows greater tendency to affect the structural and electrical properties of SnO2 thin films which composed of nanoparticles.

  17. A probabilistic framework for single-sensor acoustic emission source localization in thin metallic plates

    Science.gov (United States)

    Ebrahimkhanlou, Arvin; Salamone, Salvatore

    2017-09-01

    Tracking edge-reflected acoustic emission (AE) waves can allow the localization of their sources. Specifically, in bounded isotropic plate structures, only one sensor may be used to perform these source localizations. The primary goal of this paper is to develop a three-step probabilistic framework to quantify the uncertainties associated with such single-sensor localizations. According to this framework, a probabilistic approach is first used to estimate the direct distances between AE sources and the sensor. Then, an analytical model is used to reconstruct the envelope of edge-reflected AE signals based on the source-to-sensor distance estimations and their first arrivals. Finally, the correlation between the probabilistically reconstructed envelopes and recorded AE signals are used to estimate confidence contours for the location of AE sources. To validate the proposed framework, Hsu-Nielsen pencil lead break (PLB) tests were performed on the surface as well as the edges of an aluminum plate. The localization results show that the estimated confidence contours surround the actual source locations. In addition, the performance of the framework was tested in a noisy environment simulated by two dummy transducers and an arbitrary wave generator. The results show that in low-noise environments, the shape and size of the confidence contours depend on the sources and their locations. However, at highly noisy environments, the size of the confidence contours monotonically increases with the noise floor. Such probabilistic results suggest that the proposed probabilistic framework could thus provide more comprehensive information regarding the location of AE sources.

  18. Preparation and characterization of CdO thin films obtained by thermal oxidation of evaporated Cd thin films

    Science.gov (United States)

    Danţuş, C.; Rusu, G. G.; Dobromir, M.; Rusu, M.

    2008-12-01

    CdO thin films ( d = 300-400 nm) were prepared by thermal oxidation of metallic Cd thin films, vacuum evaporated onto unheated glass substrates. The as-deposited Cd films were subsequently heat treated in open atmosphere in two manners: by slowly heating, with rate of 5 K/min up to the temperature of 650 K and maintained at this temperature for 5 min, and by flash heating for 5 min at the same temperature of 650 K. The effect of oxidation procedure on the crystalline structure and electrical (temperature dependence of electrical conductivity) and optical (transmission and reflection spectra) properties of as obtained CdO films was investigated. All obtained CdO films are polycrystalline with strong preferential orientation with (1 1 1) plane parallel to the substrate. Depending on the oxidation conditions, the electrical conductivity at room temperature varied in the range 5 × 10 to 5 × 10 4 Ω -1 m -1. Also, the optical band gap was found to be of 2.20-2.22 eV for direct transitions and of 1.83-1.92 eV for the indirect ones. In this paper, the obtained results are correlated with the oxidation process that takes place during film annealing.

  19. Development of In-plane Thermal Conductivity Calculation Methods in Thin Films

    Directory of Open Access Journals (Sweden)

    A. A. Barinov

    2017-01-01

    Full Text Available The future nanoelectronics development involves using the smaller- -and-smaller-sized circuit components based on the micro- and nanostructures. This causes a growth of the specific heat flows up to 100 W/cm2. Since performance of electronic devices is strongly dependent on the temperature there is a challenge to create the heat transfer models, which take into account the size effect and ensure a reliable estimate of the thermal conductivity. This is one of the crucial tasks for development of new generations of integrated circuits.The paper studies heat transfer processes using the silicon thin films as an example. Thermal conductivity calculations are performed taking into account the influence of the classical size effect in the context of the Sondheimer model based on the solution of the Boltzmann transport equation.The paper, for the first time, presents and considers the influence of various factors on the thermal conductivity of thin films, namely temperature, film thickness, polarization of the phonon waves (transverse and longitudinal, velocity and relaxation time versus frequency for the phonons of different wave types.Based on the analysis, three models with different accuracy are created to estimate the influence of detailing processes under consideration on the thermal conductivity in a wide range of temperatures (from 10 K to 450 К and film thickness (from 10 nm to 100 µm.So in the model I for the first time in calculating thermal conductivity of thin films we properly and circumstantially take into account the dependence of the velocity and the relaxation time of phonons on the frequency and polarization. The obtained values are in a good agreement with available experimental data and theoretical models of other authors. In the following models we use few average methods for relaxation times and velocities, which leads to significant reduction in calculating accuracy up to the values exceeding 100%.Therefore, when calculating

  20. A direct differential method for measuring thermal conductivity of thin films.

    Science.gov (United States)

    Zeng, Yuqiang; Marconnet, Amy

    2017-04-01

    Over the past two decades, significant progress in the thermal metrology for thin films and wires has enabled new understanding of the thermal conductivity of nanostructures. However, a large variation in the measured thermal conductivity of similar nanostructured samples has been observed. In addition to potential differences from sample-to-sample, measurement uncertainty contributes to the observed variation in measured properties. Many now standard micro/nanoscale thermal measurement techniques require extensive calibration of the properties of the substrate and support structures and this calibration contributes to uncertainty. Within this work, we develop a simple, direct differential electrothermal measurement of thermal conductivity of micro/nanoscale sample films by extending conventional steady state electrothermal approaches. Specifically, we leverage a cross-beam measurement structure consisting of a suspended, composite heater beam (metal on silicon) with the sample structure (silicon) extending at a right angle from the center of the heater beam, in a configuration similar to the T-type measurements used for fibers and nanotubes. To accurately resolve the thermal conductivity of the sample, the steady-state Joule heating response of the cross-beam structure is measured. Then, the sample is detached from the heater beam with a Focused Ion Beam (FIB) tool enabling direct characterization of the composite heater beam thermal properties. The differential measurement of the structure before and after FIB cut enables direct extraction of the sample thermal conductivity. The effectiveness of this differential measurement technique is demonstrated by measuring thermal conductivity of a 200 nm silicon layer. Additionally, this new method enables investigation of the accuracy of conventional approaches for extracting sample thermal conductivity with the composite beam structure and conventional comparative approaches. The results highlight the benefits of the

  1. Structural Topograohy Optimization for Thin-plate Based on Isogeometric Analysis

    Science.gov (United States)

    Zou, Zhihui; Zhu, Denglin; Lou, Lilv; Liu, Huishan; He, Gang

    2017-09-01

    To satisfy high performance requirements for some structures, it is desirable for structure to be designed smaller, thinner and lighter in automobile and aerospace industries, etc. One prominent example is the application of topography stiffened structures. The stiffness of a structure can be increased obviously by stiffeners under a given amount of material. This paper gives an approach to optimize the structural topography design of thin-walled structures automatically based on isogeometric analysis. Optimization model, sensitivity analysis and optimization process for structural topography design are described and studied in details. The objective function is minimum compliance of structure, and the y-value(vertical coordinate value) of control points as design variables. Then structural topography is formed with changing the y-value of control points in design domain according to the specific algorithm. Several examples illustrate that the proposed method works well.

  2. Direct synthesis and characterization of optically transparent conformal zinc oxide nanocrystalline thin films by rapid thermal plasma CVD

    National Research Council Canada - National Science Library

    Pedersen, Joachim D; Esposito, Heather J; Teh, Kwok Siong

    2011-01-01

    We report a rapid, self-catalyzed, solid precursor-based thermal plasma chemical vapor deposition process for depositing a conformal, nonporous, and optically transparent nanocrystalline ZnO thin film at 130 Torr (0.17 atm...

  3. Evaluation of Specific Heat, Sound Velocity and Lattice Thermal Conductivity of Strained Nanocrystalline Bismuth Antimony Telluride Thin Films

    Science.gov (United States)

    Zheng, D.; Tanaka, S.; Miyazaki, K.; Takashiri, M.

    2015-06-01

    To investigate the effect of strain on specific heat, sound velocity and lattice thermal conductivity of nanocrystalline bismuth antimony telluride thin films, we performed both experimental study and modeling. The nanocrystalline thin films had mostly preferred crystal orientation along c-axis, and strains in the both directions of c-axis and a- b-axis. It was found that the thermal conductivity of nanocrystalline thin films decreased greatly as compared with that of bulk alloys. To gain insight into the thermal transport in the strained nanocrystalline thin films, we estimated the lattice thermal conductivity based on the phonon transport model of full distribution of mean free paths accounting for the effects of grain size and strain which was influenced to both the sound velocity and the specific heat. As a result, the lattice thermal conductivity was increased when the strain was shifted from compressive to tensile direction. We also confirmed that the strain was influenced by the lattice thermal conductivity but the reduction of the lattice thermal conductivity of thin films can be mainly attributed to the nano-size effect rather than the strain effect. Finally, it was found that the measured lattice thermal conductivities were in good agreement with modeling.

  4. Colloidal electroconvection in a thin horizontal cell. II. Bulk electroconvection of water during parallel-plate electrolysis.

    Science.gov (United States)

    Han, Yilong; Grier, David G

    2006-10-14

    We recently have reported [J. Chem. Phys. 122, 164701 (2005)] a family of electroconvective patterns that arise when charge-stabilized colloidal dispersions are driven by constant (dc) vertical electric fields. Competition between gravity and electrokinetic forces acting on the individual spheres in this system leads to the formation of highly organized convective instabilities involving hundreds of spheres. Here, we report a distinct class of electroconvective patterns that emerge in confined aqueous dispersions at higher biases. These qualitatively resemble the honeycomb and labyrinthine patterns formed during thermally driven Rayleigh-Benard convection, but arise from a distinct mechanism. Unlike the localized colloidal electroconvective patterns observed at lower biases, moreover, these system-spanning patterns form even without dispersed colloidal particles. Rather, they appear to result from an underlying electroconvective instability during electrolysis in the parallel plate geometry. This contrasts with recent theoretical results suggesting that simple electrolytes are linearly stable against electroconvection.

  5. Shape effects of nanoparticles on the squeezed flow between two Riga plates in the presence of thermal radiation

    Science.gov (United States)

    Ahmed, Naveed; Adnan; Khan, Umar; Tauseef Mohyud-Din, Syed; Waheed, Asif

    2017-07-01

    This paper aims to explore the flow of water saturated with copper nanoparticles of different shapes between parallel Riga plates. The plates are placed horizontally in the coordinate axis. Influence of the linear thermal radiation is also taken into account. The equations governing the flow have been transformed into a nondimensional form by employing a set of similarity transformations. The obtained system is solved analytically (variation-of-parameters method) and numerically (Runge-Kutta scheme). Under certain conditions, a special case of the model is also explored. Furthermore, influences of the physical quantities on velocity and thermal fields are discussed with the graphical aid over the domain of interest. The quantities of engineering and practical interest (skin friction coefficient and local rate of heat transfer) are also explored graphically.

  6. Thermally evaporated conformal thin films on non-traditional/non-planar substrates

    Science.gov (United States)

    Pulsifer, Drew Patrick

    Conformal thin films have a wide variety of uses in the microelectronics, optics, and coatings industries. The ever-increasing capabilities of these conformal thin films have enabled tremendous technological advancement in the last half century. During this period, new thin-film deposition techniques have been developed and refined. While these techniques have remarkable performance for traditional applications which utilize planar substrates such as silicon wafers, they are not suitable for the conformal coating of non-traditional substrates such as biological material. The process of thermally evaporating a material under vacuum conditions is one of the oldest thin-film deposition techniques which is able to produce functional film morphologies. A drawback of thermally evaporated thin films is that they are not intrinsically conformal. To overcome this, while maintaining the advantages of thermal evaporation, a procedure for varying the substrates orientation with respect to the incident vapor flux during deposition was developed immediately prior to the research undertaken for this doctoral dissertation. This process was shown to greatly improve the conformality of thermally evaporated thin films. This development allows for several applications of thermally evaporated conformal thin films on non-planar/non-traditional substrates. Three settings in which to evaluate the improved conformal deposition of thermally evaporated thin films were investigated for this dissertation. In these settings the thin-film morphologies are of different types. In the first setting, a bioreplication approach was used to fabricate artificial visual decoys for the invasive species Agrilus planipennis, commonly known as the emerald ash borer (EAB). The mating behavior of this species involves an overflying EAB male pouncing on an EAB female at rest on an ash leaflet before copulation. The male spots the female on the leaflet by visually detecting the iridescent green color of the

  7. Thin-film 'Thermal Well' Emitters and Absorbers for High-Efficiency Thermophotovoltaics

    CERN Document Server

    Tong, Jonathan K; Huang, Yi; Boriskina, Svetlana V; Chen, Gang

    2015-01-01

    A new approach is introduced to significantly improve the performance of thermophotovoltaic (TPV) systems by using low-dimensional thermal emitters and photovoltaic (PV) cells. By reducing the thickness of both the emitter and the PV cell, strong spectral selectivity in both thermal emission and absorption can be achieved by confining photons in trapped waveguide modes inside the thin-films that act as thermal analogs to quantum wells. Simultaneously, photo-excited carriers travel shorter distances across the thin-films reducing bulk recombination losses resulting in a lower saturation current in the PV cell. We predict a TPV efficiency enhancement with near-field coupling between the thermal emitter and the PV cell of up to 38.7% using a germanium (Ge) emitter at 1000 K and a gallium antimonide (GaSb) cell with optimized thicknesses separated by 100 nm. Even in the far-field limit, the efficiency is predicted to reach 31.5%, which is an order of magnitude higher than the Shockley Queisser limit of 1.6% for a...

  8. New approach for sensitive photothermal detection of C60 and C70 fullerenes on micro-thin-layer chromatographic plates.

    Science.gov (United States)

    Suszyński, Zbigniew; Zarzycki, Paweł K

    2015-03-10

    In this paper the pulse thermovision (photothermal) detection and quantification methods of C60 and C70 fullerenes are presented. Quantification results are compared with optical and fluorescence measurements. Target components were separated under isothermal conditions (30 °C) on micro-TLC plates (RP18WF254S) using n-hexane as the mobile phase. The principle of described analytical protocol is based on sensitive measurement of the temperature contrast generated within TLC stationary phase and fullerenes spots after white light pulse excitation. It has been demonstrated that observed temperature contrast is mainly driven by the optical properties of fullerenes (UV-vis absorption spectra). Contrary to the commonly applied optical reflection or transmission techniques the proposed thermovision method involves dissipated light. The results of presented experimental work have revealed that both types of quantitative measurements provide similar outcome despite the key differences in the signal origin. However, it has been found that thermovision method was characterized by smaller value of LOD, particularly for C60 molecule. We demonstrated that application of correlation technique to post-acquisition analysis of the sequence of temperature contrast images significantly increase detection limits of fullerenes, even in comparison to fluorescence quenching detection mode. Moreover, the thermal contrast images and particularly, computed correlation image, allow detection of stationary phase layer nonuniformities, including changes in the adsorbent thickness and thermal conductivity. Therefore, invented pulsed thermovision methodology can be additionally used for fast quality screening of home made and commercially available TLC plates. Copyright © 2014 Elsevier B.V. All rights reserved.

  9. Electrically-controlled near-field radiative thermal modulator made of graphene-coated silicon carbide plates

    Science.gov (United States)

    Yang, Yue; Wang, Liping

    2017-08-01

    In this work, we propose a hybrid near-field radiative thermal modulator made of two graphene-covered silicon carbide (SiC) plates separated by a nanometer vacuum gap. The near-field photon tunneling between the emitter and receiver is modulated by changing graphene chemical potentials with symmetrically or asymmetrically applied voltage biases. The radiative heat flux calculated from fluctuational electrodynamics significantly varies with graphene chemical potentials due to tunable near-field coupling strength between graphene plasmons across the vacuum gap. Thermal modulation and switching, which are the key functionalities required for a thermal modulator, are theoretically realized and analyzed. Newly introduced quantities of the modulation factor, the sensitivity factor and switching factor are studied quite extensively in a large parameter range for both graphene chemical potential and vacuum gap distance. This opto-electronic device with faster operating mode, which is in principle only limited by electronics and not by the thermal inertia, will facilitate the practical application of active thermal management, thermal circuits, and thermal computing with photon-based near-field thermal transport.

  10. MORPHOLOGY, THERMAL STABILITY, AND SOLDERABILITY OF ELECTROLESS NICKEL–PHOSPHORUS PLATING LAYER

    OpenAIRE

    JEONG-WON YOON; HYUN-SUK CHUN; HAN-BYUL KANG; MIN-HO PARK; CHEOL-WOONG YANG; HOO-JEONG LEE; SEUNG-BOO JUNG

    2007-01-01

    We studied the growth kinetics and characteristics of electroless nickel–phosphorus (EN–P) deposition layer on Cu substrate in an acid plating bath with sodium hypophosphite as the reducing agent. The individual nodules of the EN–P layer increased in size but decreased in number with increasing plating time and pH, i.e. the root-mean-square (RMS) roughness of the EN deposit decreased. In addition, the plating rate of the EN layer increased with increasing plating bath pH. X-ray diffraction (X...

  11. Different motion modes of a mobile plate on top of a thermally convecting fluid

    Science.gov (United States)

    Mao, Yadan; Zhong, Jin-Qiang; Zhang, Jun

    2016-11-01

    Numerical simulations are conducted to model the dynamics of a mobile, insulating plate floating on top of a Rayleigh-Benard convecting fluid with infinite Prandtl number in a two dimensional rectangular domain, which is roughly analogues to the geological model of continent drift over mantle. We focus on the effect of plate size on the dynamic feedback between the plate and the underlying convection. Four different modes of coupling are revealed as plate size varies. Among them, two transient stable modes are identified: 1. a very small plate tends to linger for long time over a cold downwelling bordering two counter-rotating convection cells; 2. a relatively small plate sometimes lingers over an upwelling plume bordering two convection cells with cold downwellings on the edges of the plate. A relatively large plate rides on a moving convection cell and oscillates periodically between the two ends walls. A very large plate executes only small excursions in response to the competition between the two neighbouring cells underneath and no longer touches the end walls. These modes are well related to different continent motions since the breakup of the Pangaea supercontinent.

  12. Fabrication of 3D Microfluidic Devices by Thermal Bonding of Thin Poly(methyl methacrylate) Films

    KAUST Repository

    Perez, Paul

    2012-07-01

    The use of thin-film techniques for the fabrication of microfluidic devices has gained attention over the last decade, particularly for three-dimensional channel structures. The reasons for this include effective use of chip volume, mechanical flexibility, dead volume reduction, enhanced design capabilities, integration of passive elements, and scalability. Several fabrication techniques have been adapted for use on thin films: laser ablation and hot embossing are popular for channel fabrication, and lamination is widely used for channel enclosure. However, none of the previous studies have been able to achieve a strong bond that is reliable under moderate positive pressures. The present work aims to develop a thin-film process that provides design versatility, speed, channel profile homogeneity, and the reliability that others fail to achieve. The three building blocks of the proposed baseline were fifty-micron poly(methyl methacrylate) thin films as substrates, channel patterning by laser ablation, and device assembly by thermal-fusion bonding. Channel fabrication was characterized and tuned to produce the desired dimensions and surface roughness. Thermal bonding was performed using an adapted mechanical testing device and optimized to produce the maximum bonding strength without significant channel deformation. Bonding multilayered devices, incorporating conduction lines, and integrating various types of membranes as passive elements demonstrated the versatility of the process. Finally, this baseline was used to fabricate a droplet generator and a DNA detection chip based on micro-bead agglomeration. It was found that a combination of low laser power and scanning speed produced channel surfaces with better uniformity than those obtained with higher values. In addition, the implemented bonding technique provided the process with the most reliable bond strength reported, so far, for thin-film microfluidics. Overall, the present work proved to be versatile

  13. FINITE ELEMENT SIMULATION FOR STRUCTURAL RESPONSE OF U7MO DISPERSION FUEL PLATES VIA FLUID-THERMAL-STRUCTURAL INTERACTION

    Energy Technology Data Exchange (ETDEWEB)

    Hakan Ozaltun; Herman Shen; Pavel Madvedev

    2010-11-01

    This article presents numerical simulation of dispersion fuel mini plates via fluid–thermal–structural interaction performed by commercial finite element solver COMSOL Multiphysics to identify initial mechanical response under actual operating conditions. Since fuel particles are dispersed in Aluminum matrix, and temperatures during the fabrication process reach to the melting temperature of the Aluminum matrix, stress/strain characteristics of the domain cannot be reproduced by using simplified models and assumptions. Therefore, fabrication induced stresses were considered and simulated via image based modeling techniques with the consideration of the high temperature material data. In order to identify the residuals over the U7Mo particles and the Aluminum matrix, a representative SEM image was employed to construct a microstructure based thermo-elasto-plastic FE model. Once residuals and plastic strains were identified in micro-scale, solution was used as initial condition for subsequent multiphysics simulations at the continuum level. Furthermore, since solid, thermal and fluid properties are temperature dependent and temperature field is a function of the velocity field of the coolant, coupled multiphysics simulations were considered. First, velocity and pressure fields of the coolant were computed via fluidstructural interaction. Computed solution for velocity fields were used to identify the temperature distribution on the coolant and on the fuel plate via fluid-thermal interaction. Finally, temperature fields and residual stresses were used to obtain the stress field of the plates via fluid-thermal-structural interaction.

  14. Advancements in ion beam figuring of very thin glass plates (Conference Presentation)

    Science.gov (United States)

    Civitani, M.; Ghigo, M.; Hołyszko, J.; Vecchi, G.; Basso, S.; Cotroneo, V.; DeRoo, C. T.; Schwartz, E. D.; Reid, P. B.

    2017-09-01

    The high-quality surface characteristics, both in terms of figure error and of micro-roughness, required on the mirrors of a high angular resolution x-ray telescope are challenging, but in principle well suited with a deterministic and non-contact process like the ion beam figuring. This process has been recently proven to be compatible even with very thin (thickness around 0.4mm) sheet of glasses (like D263 and Eagle). In the last decade, these types of glass have been investigated as substrates for hot slumping, with residual figure errors of hundreds of nanometres. In this view, the mirrors segments fabrication could be envisaged as a simple two phases process: a first replica step based on hot slumping (direct/indirect) followed by an ion beam figuring which can be considered as a post-fabrication correction method. The first ion beam figuring trials, realized on flat samples, showed that the micro-roughness is not damaged but a deeper analysis is necessary to characterize and eventually control/compensate the glass shape variations. In this paper, we present the advancements in the process definition, both on flat and slumped glass samples.

  15. The turbulence structure of the wake of a thin flat plate at post-stall angles of attack

    Science.gov (United States)

    Mohebi, Meraj; Wood, David H.; Martinuzzi, Robert J.

    2017-06-01

    The influence of post-stall angles of attack, α, on the turbulent flow characteristics behind a thin high aspect ratio flat plate was investigated experimentally. Time-resolved stereo particle image velocimetry was used in an open-section wind tunnel at a Reynolds number of 6600. The mean field was determined along with the wake topology, force coefficients, vortex shedding frequency, and the terms in the transport equation for the turbulent kinetic energy k. Coherent and incoherent contributions to the Reynolds stress and k-transport terms were estimated. Over the measured range of 20° ≤ α ≤ 90°, quasi-periodic vortex shedding is observed and it is shown that most of the fluctuation energy contribution in the wake arises from coherent fluctuations associated with vortex shedding. As the angle of attack is reduced from 90°, the length of the recirculation region and the drag decrease, while the shedding frequency increases monotonically. In contrast, mean lift and k are maximized at α ≈ 40°, suggesting a relationship between the bound vortex circulation and the levels of k. Structural differences in the mean strain field, wake topology, relative contributions to the k-production terms, and significant differences in the incoherent field suggest changes in the wake dynamics for α > 40° and 20° ≤ α ≤ 40°. For α > 40°, coherent contributions to the fluctuation field result in a large region close to the plate exhibiting small levels of negative mean production and generally low levels of advection, despite very high levels of production just downstream of the recirculation region.

  16. The transition from linear to diffuse plate boundary in the Azores-Gibraltar region: results from a thin-sheet model

    Science.gov (United States)

    Jiménez-Munt, Ivone; Fernàndez, Manel; Torne, Montse; Bird, Peter

    2001-10-01

    We use the thin-sheet plane-stress approach to study the present-day dynamic behavior of the plate boundary between Eurasia and Africa along the Azores-Gibraltar region. This plate boundary, which extends from the Azores triple junction to the Gibraltar strait, shows a tectonic regime that changes from transtension in the west to transpression in the east, with a strike-slip motion in its central segment. Seismological data reveal that the western and central segments are currently marked by a linear series of earthquakes indicating that the plate boundary is located in a narrow zone. In contrast, the eastern segment is not so well defined and deformation spreads over a much broader area. To apply the thin-sheet approach, we combined heat flow, elevation and crustal thickness data to calculate the steady-state geotherm and the total strength of the lithosphere. Several models with different fault friction coefficients and geometries at the eastern segment of the plate boundary were tested. Results are compared with the maximum compressive stress directions from the World Stress Map, and the calculated seismic strain rates and slip vectors from earthquake data. The best fitting models are consistent with the rotation pole of Argus et al. [D.F. Argus et al., J. Geophys. Res. 94 (1989) 5585-5602], and show that the rheological behavior of the plate boundary must necessarily change from the western and central segments to the eastern segment. The diffuse character of the plate boundary east of the Gorringe Bank is dominated by the transition from oceanic to continental lithosphere, the weakness of the Alboran domain, and the convergence between the African and the Eurasian plates. The displacement of the Alboran domain relative to the African plate may play a major role in stress propagation through the Iberian Peninsula and its Atlantic margin.

  17. Thermal oxidation of Zr–Cu–Al–Ni amorphous metal thin films

    Energy Technology Data Exchange (ETDEWEB)

    Oleksak, R.P.; Hostetler, E.B.; Flynn, B.T. [School of Chemical, Biological and Environmental Engineering, Oregon State University, Corvallis, OR 97331 (United States); McGlone, J.M.; Landau, N.P.; Wager, J.F. [School of Electrical Engineering and Computer Science, Oregon State University, Corvallis, OR 97331 (United States); Stickle, W.F. [Hewlett-Packard Company, Corvallis, OR 97333 (United States); Herman, G.S., E-mail: greg.herman@oregonstate.edu [School of Chemical, Biological and Environmental Engineering, Oregon State University, Corvallis, OR 97331 (United States)

    2015-11-30

    The initial stages of thermal oxidation for Zr–Cu–Al–Ni amorphous metal thin films were investigated using X-ray photoelectron spectroscopy, transmission electron microscopy and energy dispersive X-ray spectroscopy. The as-deposited films had oxygen incorporated during sputter deposition, which helped to stabilize the amorphous phase. After annealing in air at 300 °C for short times (5 min) this oxygen was found to segregate to the surface or buried interface. Annealing at 300 °C for longer times leads to significant composition variation in both vertical and lateral directions, and formation of a surface oxide layer that consists primarily of Zr and Al oxides. Surface oxide formation was initially limited by back-diffusion of Cu and Ni (< 30 min), and then by outward diffusion of Zr (> 30 min). The oxidation properties are largely consistent with previous observations of Zr–Cu–Al–Ni metallic glasses, however some discrepancies were observed which could be explained by the unique sample geometry of the amorphous metal thin films. - Highlights: • Thermal oxidation of amorphous Zr–Cu–Al–Ni thin films was investigated. • Significant short-range inhomogeneities were observed in the amorphous films. • An accumulation of Cu and Ni occurs at the oxide/metal interface. • Diffusion of Zr was found to limit oxide film growth.

  18. Marangoni effects on a thin liquid film coating a sphere with axial or radial thermal gradients

    Science.gov (United States)

    Kang, Di; Nadim, Ali; Chugunova, Marina

    2017-07-01

    We study the time evolution of a thin liquid film coating the outer surface of a sphere in the presence of gravity, surface tension, and thermal gradients. We derive the fourth-order nonlinear partial differential equation that models the thin film dynamics, including Marangoni terms arising from the dependence of surface tension σ on temperature T. We consider two different imposed temperature distributions with axial or radial thermal gradients. We analyze the stability of a uniform coating under small perturbations and carry out numerical simulations in COMSOL for a range of parameter values. In the case of an axial temperature gradient, we find steady states either with uniform film thickness or with the fluid accumulating at the bottom or near the top of the sphere, depending on the total volume of liquid in the film, dictating whether gravity or Marangoni effects dominate. This suggests a potential method for the indirect measurement of d σ /d T by monitoring the thickness profile of the thin film. In the case of a radial temperature gradient, a stability analysis reveals the most unstable non-axisymmetric modes on an initially uniform coating film.

  19. Crystallization Behavior and Thermal Analysis of CoFeB Thin Films

    Directory of Open Access Journals (Sweden)

    Jiun-Yi Tseng

    2015-01-01

    Full Text Available We examined two targets containing Co40Fe40B20 and Co60Fe20B20. We deposited Co40Fe40B20 and Co60Fe20B20 monolayer thin films of various thicknesses on glass substrates through DC magnetron sputtering; the thicknesses ranged from 25 to 200 Å. The thermal properties of the Co40Fe40B20 and Co60Fe20B20 thin films were determined using a differential scanning calorimeter (DSC. The thermal properties included the glass transition temperature (Tg, onset crystallization temperature (Tx, and glass-forming ability, which were determined according to these values. Using the Kissinger formula revealed that the activation energy of the Co60Fe20B20 with a thickness of 75 Å is the highest, implying that crystallization was the lowest and the Co60Fe20B20 film showed anticrystallization properties. However, the energy of 75 Å Co40Fe40B20 thin films was the lowest, which is opposite to that of Co60Fe20B20. This observation can be reasonably explained based on the concentration of Co or Fe. Therefore, a thickness of 75 Å is critical.

  20. Structural, Optical, and Dielectric Properties of Azure B Thin Films and Impact of Thermal Annealing

    Science.gov (United States)

    Zeyada, H. M.; Zidan, H. M.; Abdelghany, A. M.; Abbas, I.

    2017-07-01

    Thin films of azure B (AB) have been prepared by thermal evaporation. Structural, optical, and dielectric characteristics of as-prepared and annealed samples were studied. AB is polycrystalline in as-synthesized powder form. Detailed x-ray diffraction studies showed amorphous structure for pristine and annealed films. Fourier-transform infrared vibrational spectroscopy indicated minor changes in molecular bonds of AB thin films either after deposition or after thermal annealing. Optical transmittance and reflection spectra of prepared thin films were studied at nearly normal light incidence in the spectral range from 200 nm to 2500 nm, showing marked changes without new peaks. Annealing increased the absorption coefficient and decreased the optical bandgap. Onset and optical energy gaps of pristine films were found to obey indirect allowed transition with values of 1.10 eV and 2.64 eV, respectively. Annealing decreased the onset and optical energy gaps to 1.0 eV and 2.57 eV, respectively. The dispersion parameters before and after annealing are discussed in terms of a single-oscillator model. The spectra of the dielectric constants ( ɛ 1, ɛ 2) were found to depend on the annealing temperature in addition to the incident photon energy.

  1. The Feasibility of Structural Health Monitoring Using the Fundamental Shear Horizontal Guided Wave in a Thin Aluminum Plate

    Directory of Open Access Journals (Sweden)

    Jorge Franklin Mansur Rodrigues Filho

    2017-05-01

    Full Text Available Structural health monitoring (SHM is emerging as an essential tool for constant monitoring of safety-critical engineering components. Ultrasonic guided waves stand out because of their ability to propagate over long distances and because they can offer good estimates of location, severity, and type of damage. The unique properties of the fundamental shear horizontal guided wave (SH0 mode have recently generated great interest among the SHM community. The aim of this paper is to demonstrate the feasibility of omnidirectional SH0 SHM in a thin aluminum plate using a three-transducer sparse array. Descriptions of the transducer, the finite element model, and the imaging algorithm are presented. The image localization maps show a good agreement between the simulations and experimental results. The SH0 SHM method proposed in this paper is shown to have a high resolution and to be able to locate defects within 5% of the true location. The short input signal as well the non-dispersive nature of SH0 leads to high resolution in the reconstructed images. The defect diameter estimated using the full width at half maximum was 10 mm or twice the size of the true diameter.

  2. The Feasibility of Structural Health Monitoring Using the Fundamental Shear Horizontal Guided Wave in a Thin Aluminum Plate.

    Science.gov (United States)

    Franklin Mansur Rodrigues Filho, Jorge; Tremblay, Nicolas; Soares da Fonseca, Gláucio; Belanger, Pierre

    2017-05-19

    Structural health monitoring (SHM) is emerging as an essential tool for constant monitoring of safety-critical engineering components. Ultrasonic guided waves stand out because of their ability to propagate over long distances and because they can offer good estimates of location, severity, and type of damage. The unique properties of the fundamental shear horizontal guided wave (SH₀) mode have recently generated great interest among the SHM community. The aim of this paper is to demonstrate the feasibility of omnidirectional SH₀ SHM in a thin aluminum plate using a three-transducer sparse array. Descriptions of the transducer, the finite element model, and the imaging algorithm are presented. The image localization maps show a good agreement between the simulations and experimental results. The SH₀ SHM method proposed in this paper is shown to have a high resolution and to be able to locate defects within 5% of the true location. The short input signal as well the non-dispersive nature of SH₀ leads to high resolution in the reconstructed images. The defect diameter estimated using the full width at half maximum was 10 mm or twice the size of the true diameter.

  3. Flexural edge waves generated by steady-state propagation of a loaded rectilinear crack in an elastically supported thin plate.

    Science.gov (United States)

    Nobili, Andrea; Radi, Enrico; Lanzoni, Luca

    2017-08-01

    The problem of a rectilinear crack propagating at constant speed in an elastically supported thin plate and acted upon by an equally moving load is considered. The full-field solution is obtained and the spotlight is set on flexural edge wave generation. Below the critical speed for the appearance of travelling waves, a threshold speed is met which marks the transformation of decaying edge waves into edge waves propagating along the crack and dying away from it. Yet, besides these, and for any propagation speed, a pair of localized edge waves, which rapidly decay behind the crack tip, is also shown to exist. These waves are characterized by a novel dispersion relation and fade off from the crack line in an oscillatory manner, whence they play an important role in the far field behaviour. Dynamic stress intensity factors are obtained and, for speed close to the critical speed, they show a resonant behaviour which expresses the most efficient way to channel external work into the crack. Indeed, this behaviour is justified through energy considerations regarding the work of the applied load and the energy release rate. Results might be useful in a wide array of applications, ranging from fracturing and machining to acoustic emission and defect detection.

  4. Flexural edge waves generated by steady-state propagation of a loaded rectilinear crack in an elastically supported thin plate

    Science.gov (United States)

    Nobili, Andrea; Radi, Enrico; Lanzoni, Luca

    2017-08-01

    The problem of a rectilinear crack propagating at constant speed in an elastically supported thin plate and acted upon by an equally moving load is considered. The full-field solution is obtained and the spotlight is set on flexural edge wave generation. Below the critical speed for the appearance of travelling waves, a threshold speed is met which marks the transformation of decaying edge waves into edge waves propagating along the crack and dying away from it. Yet, besides these, and for any propagation speed, a pair of localized edge waves, which rapidly decay behind the crack tip, is also shown to exist. These waves are characterized by a novel dispersion relation and fade off from the crack line in an oscillatory manner, whence they play an important role in the far field behaviour. Dynamic stress intensity factors are obtained and, for speed close to the critical speed, they show a resonant behaviour which expresses the most efficient way to channel external work into the crack. Indeed, this behaviour is justified through energy considerations regarding the work of the applied load and the energy release rate. Results might be useful in a wide array of applications, ranging from fracturing and machining to acoustic emission and defect detection.

  5. Fabrication and optimization of the thermally treated titanium dioxide thin film-based ultraviolet photodetectors

    Science.gov (United States)

    Kim, Sang Hun; Lee, Soo Hyun; Yu, Jae Su

    2018-01-01

    We reported the titanium dioxide (TiO2) thin film-based metal-semiconductor-metal (MSM) ultraviolet (UV) photodetectors (PDs), fabricated by conventional photolithography and electron-beam evaporation processes, with additional annealing. The crystallinity and morphology of the thermally treated TiO2 layers were investigated. In order to optimize the performance of MSM UV PDs, the annealing temperature (T a ) and electrode spacing were adjusted. The qualified anatase TiO2 thin films without structural deformation were obtained at the T a of 600 °C. At the bias of 5 V, the high on/off ratio of 6.0 × 105 was achieved from the device with the electrode spacing of 30 μm. By switching the light on/off, the device operation was also observed. The average rise and reset times were estimated to be 34.2 and 5.5 s, respectively.

  6. Optical and Structural Properties of Thermally Evaporated Zinc Oxide Thin Films on Polyethylene Terephthalate Substrates

    Directory of Open Access Journals (Sweden)

    M. G. Faraj

    2011-01-01

    Full Text Available Zinc oxide thin films of different thicknesses ranging from 100 to 300 nm were prepared on polyethylene terephthalate substrates with thermal evaporation in a vacuum of approximately 3×10-5 Torr. X-ray diffraction patterns confirm the proper phase formation of the material. From atomic force microscopy (AFM images, it was found that the root mean square roughness of the film surface increased as the film thickness increased. The optical properties of ZnO on PET substrates were determined through the optical transmission method using an ultraviolet-visible spectrophotometer. The optical band gap values of ZnO thin films slightly decreased as the film thickness increased.

  7. Structural, optical and XPS study of thermal evaporated In2O3 thin films

    Science.gov (United States)

    Neelakanta Reddy, I.; Venkata Reddy, Ch; Cho, Migyung; Shim, Jaesool; Kim, Dongseob

    2017-08-01

    The nanostructured In2O3 thin films were deposited on Si n-type (1 0 0) substrates by reactive thermal evaporation. The structural, morphological, and oxidation states of the films were investigated using x-ray diffraction, scanning electron microscopy, atomic force microscopy, and x-ray photoelectron spectroscopy. The optical properties of the films were analyzed by UV-vis spectroscopy, Raman spectroscopy, and photoluminescence spectroscopy. The deposited films showed c-In2O3 crystalline nanostructures with a preferred diffraction peak of (2 2 2). The truncated icosahedron shape’s morphology with a transmittance of 85% was observed in the In2O3 thin films. All the deposited indium oxide films have 3+  oxidation states.

  8. Thin-layer thermal insulation coatings based on high-filled spheroplastics with polyorganosiloxane binder

    Science.gov (United States)

    Chukhlanov, V. Yu; Selivanov, O. G.; Trifonova, T. A.; Ilina, M. E.; Chukhlanova, N. V.

    2017-10-01

    Thermal insulation coatings, based on polyorganosiloxane as a binder and hollow glass microspheres, have been studied in this research. The developed materials are widely applied in various branches of science and engineering basically in construction. Components interaction processes are comprehensively studied. Spraying production methods of thin layer thermal insulation coatings have been researched. Ideal technological parameters for polyorganosiloxane coatings hardening depending on components ratio, ambient temperature, solvent and curative concentration have been determined. Stress related characteristics of constructional energy saving materials containing polyorganosiloxane have been researched. Components structure and ratio concerning compound extension strength properties have been revealed. Substantiation of Danneberg model application for the strength characteristics enhancing, when hollow microspheres are introduced, has been suggested. Thermal properties of coating thermal insulation have been studied. To research these characteristics standard methods applying devices IT-S-400 and IT-λ-400 have been chosen. Filler concentration increase was stated to decrease the composition heat conductivity coefficient and to the reduction of temperature dependence of this index. The authors suggested to employ the developed thermal insulation materials for construction and power engineering facilities operating under high temperature and other unfavorable environment.

  9. Experimental Investigation of Size Effects on the Thermal Conductivity of Silicon-Germanium Alloy Thin Films

    Science.gov (United States)

    Cheaito, Ramez; Duda, John C.; Beechem, Thomas E.; Hattar, Khalid; Ihlefeld, Jon F.; Medlin, Douglas L.; Rodriguez, Mark A.; Campion, Michael J.; Piekos, Edward S.; Hopkins, Patrick E.

    2012-11-01

    We experimentally investigate the role of size effects and boundary scattering on the thermal conductivity of silicon-germanium alloys. The thermal conductivities of a series of epitaxially grown Si1-xGex thin films with varying thicknesses and compositions were measured with time-domain thermoreflectance. The resulting conductivities are found to be 3 to 5 times less than bulk values and vary strongly with film thickness. By examining these measured thermal conductivities in the context of a previously established model, it is shown that long wavelength phonons, known to be the dominant heat carriers in alloy films, are strongly scattered by the film boundaries, thereby inducing the observed reductions in heat transport. These results are then generalized to silicon-germanium systems of various thicknesses and compositions; we find that the thermal conductivities of Si1-xGex superlattices are ultimately limited by finite size effects and sample size rather than periodicity or alloying. This demonstrates the strong influence of sample size in alloyed nanosystems. Therefore, if a comparison is to be made between the thermal conductivities of superlattices and alloys, the total sample thicknesses of each must be considered.

  10. An investigation on thermal and friction effect produced by friction welding of SA 213 tube to SA 387 tube plate

    Directory of Open Access Journals (Sweden)

    S. Pandia Rajan

    2016-03-01

    Full Text Available The present study investigates the effect of thermal and friction produced in the tube to tube plate during the friction welding process by using a Tungsten carbide external tool. In this process, the fictional welding of SA 213 tube and SA 387 tube plate was done by using an external tool. Modeling of tool and wok piece is done by using Solid works and to study the thermal and frictional effect by using Ansys. In this research work, joining of SA 213 tube to SA 387 tube plate was done by using two different techniques such as with hole [WH] and without hole [WOH]. The stress value of with hole and without hole such as 18,782 MPa and 10,486 MPa respectively and the ultimate heat flux generated with hole and without hole such as 0.80475 W/mm2 and 1.1344 W/mm2 respectively were observed.

  11. Effects of bath composition on the morphology of electroless-plated Cu electrodes for hetero-junctions with intrinsic thin layer solar cell

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Woon Young [Surface Technology R& BD Group, Korea Institute of Industrial Technology (KITECH), Gaetbeol-ro 156, Yeonsu-gu, Incheon 406-840 (Korea, Republic of); Lee, Yu Jin [Surface Technology R& BD Group, Korea Institute of Industrial Technology (KITECH), Gaetbeol-ro 156, Yeonsu-gu, Incheon 406-840 (Korea, Republic of); Department of Materials Science & Engineering, Yonsei University, Yonsei-ro 50, Seodaemun-Gu, Seoul 120-749 (Korea, Republic of); Lee, Min Hyung, E-mail: minhyung@kitech.re.kr [Surface Technology R& BD Group, Korea Institute of Industrial Technology (KITECH), Gaetbeol-ro 156, Yeonsu-gu, Incheon 406-840 (Korea, Republic of)

    2015-07-31

    The morphology of an electroless-plated Cu electrode was investigated as a function of bath composition. To enhance the selectivity of Cu electrode deposition on the surface of an indium tin oxide layer, a Ti/Cu multi-layer was deposited as a Cu electrode seed layer by physical vapor deposition, and then electroless plating was performed using various complexing agents and a surfactant. The degree of selectivity was effectively influenced by the type of complexing agent. The electroless plating solution containing N,N,N′,N′-tetrakis(2-hydroxypropyl)ethylenediamine (THPED) as complexing agent showed excellent selective growth of the Cu electrode as compared to the solution containing ethylenediaminetetraacetic acid. Even though THPED led to better selective growth of the electroless-plated Cu electrode, the aspect ratio of electrode lateral growth was about 2.7 times that of vertical growth. By adding a nonionic surfactant, the ratio between vertical growth rate and lateral growth rate was improved about 4.6 times. The Cu–THPED electroless plating with nonionic surfactant provided a drastic decrease in lateral growth rate, compared with the Cu–THPED electroless plating bath excluding nonionic surfactant. The Cu–THPED solution including nonionic surfactant is a promising composition of electroless plating solution for the clear selective plating of Cu electrodes on hetero-junctions with intrinsic thin layer solar cells. - Highlights: • Selective electroless plating (SEP) depends on binding strength of complexing agent. • The SEP was performed using Cu-N,N,N′,N′-tetrakis(2-hydroxypropyl)ethylenediamine. • A surfactant is able to remove hydrogen bubbles on Cu electrode surface. • The growth of Cu electrode was improved in vertical direction by adding surfactant.

  12. Effect of thermal annealing on ZnO:Al thin films grown by spray pyrolysis

    Science.gov (United States)

    El Manouni, A.; Manjón, F. J.; Perales, M.; Mollar, M.; Marí, B.; Lopez, M. C.; Ramos Barrado, J. R.

    2007-07-01

    We report the effect of thermal annealing in air on the structural and optical properties of undoped and aluminium-doped (1%-4%) zinc oxide (AZO) thin films, grown by the spray pyrolysis technique on quartz substrates. Films were characterized by X-ray diffraction, low-temperature photoluminescence, electrical resistivity, and Raman spectroscopy after annealing at temperatures between 500 and 900 ∘C. Annealing in air improves the long-range order crystalline quality of the bulk crystals, but promotes a number of point defects in the surface affecting both the resistivity and the photoluminescence.

  13. Thermal performance of a vapor chamber-based plate of high-power light-emitting diodes filled with Al2O3 nanofluid.

    Science.gov (United States)

    Wang, Jung-Chang; Lin, Cherng-Yuan; Chen, Teng-Chieh

    2013-04-01

    Nanofluid that contains Al2O3 nanoparticles evenly dispersed in deionized water is considered to have superior heat transfer characteristics due to the significant increase in both collision frequency and contact surface area between the nanoparticles and the deionized water. The thermal performance of the vapor chamber-based plate of a high power light-emitting diode (LED) filled with Al2O3 nanofluid was experimentally investigated. The thermal characteristics of the vapor chamber were also compared with those of copper- and aluminum-based plates exposed to the heating source of four single-crystal LEDs. The experimental results show that the effective thermal conductivity of the vapor chamber increased with an increase in heat flux. A higher heating power caused an increase in the temperature variation in the vapor chamber, the illumination of the vapor chamber-, copper-, and aluminum-based plates, and the material resistance of the copper- and aluminum-based plates. In contrast, the spreading, convective, and total thermal resistance all decreased with an increase in heating power for all three base plates. The total thermal resistance of the vapor chamber is mostly due to its spreading thermal resistance, and appeared to be lower than that of the copper- and aluminum-based plates under a heating power of over 5 Watts.

  14. IER-297 CED-2: Final Design for Thermal/Epithermal eXperiments with Jemima Plates with Polyethylene and Hafnium

    Energy Technology Data Exchange (ETDEWEB)

    Nelson, A. J. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Percher, C. M. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Zywiec, W. J. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Heinrichs, D. P. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2018-01-11

    This report presents the final design (CED-2) for IER-297, and focuses on 15 critical configurations using highly enriched uranium (HEU) Jemima plates moderated by polyethylene with and without hafnium diluent. The goal of the U.S. Nuclear Criticality Safety Program’s Thermal/Epithermal eXperiments (TEX) is to design and conduct new critical experiments to address high priority nuclear data needs from the nuclear criticality safety and nuclear data communities, with special emphasis on intermediate energy (0.625 eV – 100 keV) assemblies that can be easily modified to include various high priority diluent materials. The TEX (IER 184) CED-1 Report [1], completed in 2012, demonstrated the feasibility of meeting the TEX goals with two existing NCSP fissile assets, plutonium Zero Power Physics Reactor (ZPPR) plates and highly enriched uranium (HEU) Jemima plates. The first set of TEX experiments will focus on using the plutonium ZPPR plates with polyethylene moderator and tantalum diluents.

  15. Pervasive seismic low-velocity zones within stagnant plates in the mantle transition zone: Thermal or compositional origin?

    Science.gov (United States)

    Tauzin, B.; Kim, S.; Kennett, B. L. N.

    2017-11-01

    We exploit conversions between P and S waves for large-scale, high-resolution imaging of the mantle transition zone beneath Northwest Pacific and the margin of Eastern Asia. We find pervasive reflectivity concentrated in two bands with apparent wave-speed reduction of -2% to -4% about 50 km thick at the top of the transition zone and 100 km thick at the bottom. This negative reflectivity associated with the scattered-waves at depth is interpreted jointly with larger-scale mantle tomographic images, and is shown to delineate the stagnant portions of the subducted Pacific plate in the transition zone, with largely positive shear-wave velocity contrasts. The upper reflectivity zone connects to broad low-velocity regions below major intra-plate volcanoes, whereas the lower zone coincides locally with the occurrence of deep-focus earthquakes along the East Asia margin. Similar reflectivity is found in Pacific Northwest of the USA. We demonstrate that the thermal signature of plates alone is not sufficient to explain such features. Alternative explanations for these reflective zones include kinetic effects on olivine phase transitions (meta-stability), compositional heterogeneities within and above stagnant plates, complex wave-propagation effects in the heterogeneous slab structure, or a combination of such factors. We speculate that part of the negative reflectivity is the signature of compositional heterogeneities, as revealed by numerous other studies of seismic scattering throughout the mantle, and that such features could be widespread across the globe.

  16. Fire characterization and object thermal response for a large flat plate adjacent to a large JP-4 fuel fire

    Energy Technology Data Exchange (ETDEWEB)

    Gritzo, L.A.; Moya, J.L. [Sandia National Labs, Albuquerque, NM (United States); Murray, D. [Naval Air Warefare Center, China Lake, CA (United States)

    1997-01-01

    A series of three 18.9 m diameter JP-4 pool fire experiments with a large (2.1 m X 4.6 m), flat plate calorimeter adjacent to the fuel pool were recently performed. The objectives of these experiments were to: (1) gain a better understanding of fire phenomenology, (2) provide empirical input parameter estimates for simplified, deterministic Risk Assessment Compatible Fire Models (RACFMs), (3) assist in continuing fire field model code validation and development, and (4) enhance the data base of fire temperature and heat flux to object distributions. Due to different wind conditions during each experiment, data were obtained for conditions where the plate was not engulfed, fully-engulfed and partially engulfed by the continuous flame zone. Results include the heat flux distribution to the plate and flame thermocouple temperatures in the vicinity of the plate and at two cross sections within the lower region of the continuous flame zone. The results emphasize the importance of radiative coupling (i.e. the cooling of the flames by a thermally massive object) and convective coupling (including object-induced turbulence and object/wind/flame interactions) in determining the heat flux from a fire to an object. The formation of a secondary flame zone on an object adjacent to a fire via convective coupling (which increases the heat flux by a factor of two) is shown to be possible when the object is located within a distance equal to the object width from the fire.

  17. Attempts of Thermal Imaging Camera Usage in Estimations of the Convective Heat Loss From a Vertical Plate

    Directory of Open Access Journals (Sweden)

    Denda Hubert

    2014-01-01

    Full Text Available In this paper a new method for determining heat transfer coefficients using a gradient method has been developed. To verify accuracy of the proposed method vertical isothermal heating plate with natural convection mechanism has been examined. This configuration was deliberately chosen, because of the fact that such case is historically the earliest and most thoroughly studied and its rich scientific documentation – the most reliable. New method is based on temperature field visualization made in perpendicular plane to the heating surface of the plate using infrared camera. Because the camera does not record temperature of air itself but the surface only, therefore plastic mesh with low thermal conductivity has been used as a detector. Temperature of each mesh cell, placed perpendicular to the vertical heating surface and rinsed with convection stream of heated air could be already recorded by infrared camera. In the same time using IR camera surface of heating plate has been measured. By numerical processing of the results matrix temperature gradient on the surface ∂T/∂x │ x=0, local heat transfer coefficients αy, and local values of Nusselt number Nuy, can be calculated. After integration the average Nusselt number for entire plate can be calculated. Obtained relation characteristic numbers Nu = 0.647 Ra 0.236 (R2 = 0.943, has a good correlation with literature reports and proves usefulness of the method.

  18. Thermal energy conversion using near-field thermophotovoltaic device composed of a thin-film tungsten radiator and a thin-film silicon cell

    Science.gov (United States)

    Lau, Japheth Z.-J.; Wong, Basil T.

    2017-08-01

    In this paper, we proposed a novel nano-gap thermophotovoltaic (TPV) device made up of thin-films including the radiator. The optical, electrical, and thermal responses and performance of the device were assessed using coupled opto-electro-thermal numerical simulation. The device design consists of a thin-film tungsten radiator which is paired with a thin-film silicon TPV cell across a nanometric vacuum gap. Results were simulated based on experimental properties available in the current literature database. It is discovered that the maximum electrical power output of the thin-film nano-gap TPV device increases with cell temperature up to a certain threshold value due to improvements in generated photocurrent. Thin-film tungsten as a radiator is shown to improve radiative heat transfer above the bandgap compared to conventional bulk tungsten. The effect of cell thickness on responses and performance was also analysed. A 1-μm cell produces better performance over thinner thicknesses at the cost of greater cooling requirements. However, the improvements in output power offset the cooling costs, allowing for consistently favourable efficiencies. Finally, it is shown that the temperature profile in silicon thin-films under convective cooling can be approximated as uniform, simplifying the heat transport modelling process.

  19. An investigation of surface reconstruction from binocular disparity based on standard regularization theory: comparison between "membrane" and "thin-plate" potential energy models.

    Science.gov (United States)

    Shiraiwa, Aya; Hayashi, Takefumi

    2011-08-01

    Visible surfaces of three-dimensional objects are reconstructed from two-dimensional retinal images in the early stages of human visual processing. In the computational model of surface reconstruction based on the standard regularization theory, an energy function is minimized. Two types of model have been proposed, called "membrane" and "thin-plate" after their function formulas, in which the first or the second derivative of depth information is used. In this study, the threshold of surface reconstruction from binocular disparity was investigated using a sparse random dot stereogram, and the predictive accuracy of these models was evaluated. It was found that the thin-plate model reconstructed surfaces more accurately than the membrane model and showed good agreement with experimental results. The likelihood that these models imitate human processing of visual information is discussed in terms of the size of receptive fields in the visual pathways of the human cortex.

  20. Structural and compositional properties of CZTS thin films formed by rapid thermal annealing of electrodeposited layers

    Science.gov (United States)

    Lehner, J.; Ganchev, M.; Loorits, M.; Revathi, N.; Raadik, T.; Raudoja, J.; Grossberg, M.; Mellikov, E.; Volobujeva, O.

    2013-10-01

    In this work Cu2ZnSnS4 (CZTS) thin films were formed by rapid thermal annealing (RTA) of sequentially electrodeposited Cu-Zn and Sn films in 5% H2S containing atmosphere. Six different thermal profiles were used in the experiments. In three of these, the temperature ramping up was varied, while the variable in the other three profiles was the cooling down rate. The optimising parameters for RTA of electrodeposited films were found and annealed films were characterised by X-ray diffraction (XRD), micro-Raman spectroscopy, scanning electron microscopy and energy dispersive X-ray spectroscopy (SEM+EDS). The material parameters such as lattice strain and crystallite size were also determined and the influence of annealing temperature and heating rate on these parameters was discussed.The pathway of MoS2 formation was investigated.

  1. Conductivity enhancement of multiwalled carbon nanotube thin film via thermal compression method

    Science.gov (United States)

    Tsai, Wan-Lin; Wang, Kuang-Yu; Chang, Yao-Jen; Li, Yu-Ren; Yang, Po-Yu; Chen, Kuan-Neng; Cheng, Huang-Chung

    2014-08-01

    For the first time, the thermal compression method is applied to effectively enhance the electrical conductivity of carbon nanotube thin films (CNTFs). With the assistance of heat and pressure on the CNTFs, the neighbor multiwalled carbon nanotubes (CNTs) start to link with each other, and then these separated CNTs are twined into a continuous film while the compression force, duration, and temperature are quite enough for the reaction. Under the compression temperature of 400°C and the compression force of 100 N for 50 min, the sheet resistance can be reduced from 17 to 0.9 k Ω/sq for the CNTFs with a thickness of 230 nm. Moreover, the effects of compression temperature and the duration of thermal compression on the conductivity of CNTF are also discussed in this work.

  2. Thermal Molding of Organic Thin-Film Transistor Arrays on Curved Surfaces.

    Science.gov (United States)

    Sakai, Masatoshi; Watanabe, Kento; Ishimine, Hiroto; Okada, Yugo; Yamauchi, Hiroshi; Sadamitsu, Yuichi; Kudo, Kazuhiro

    2017-12-01

    In this work, a thermal molding technique is proposed for the fabrication of plastic electronics on curved surfaces, enabling the preparation of plastic films with freely designed shapes. The induced strain distribution observed in poly(ethylene naphthalate) films when planar sheets were deformed into hemispherical surfaces clearly indicated that natural thermal contraction played an important role in the formation of the curved surface. A fingertip-shaped organic thin-film transistor array molded from a real human finger was fabricated, and slight deformation induced by touching an object was detected from the drain current response. This type of device will lead to the development of robot fingers equipped with a sensitive tactile sense for precision work such as palpation or surgery.

  3. Improved electrical stability of CdS thin film transistors through Hydrogen-based thermal treatments

    KAUST Repository

    Salas Villaseñor, Ana L.

    2014-06-01

    Thin film transistors (TFTs) with a bottom-gate configuration were fabricated using a photolithography process with chemically bath deposited (CBD) cadmium sulfide (CdS) films as the active channel. Thermal annealing in hydrogen was used to improve electrical stability and performance of the resulting CdS TFTs. Hydrogen thermal treatments results in significant V T instability (V T shift) improvement while increasing the I on/I off ratio without degrading carrier mobility. It is demonstrated that after annealing V T shift and I on/I off improves from 10 V to 4.6 V and from 105 to 10 9, respectively. Carrier mobility remains in the order of 14.5 cm2 V s-1. The reduced V T shift and performance is attributed to a reduction in oxygen species in the CdS after hydrogen annealing, as evaluated by Fourier transform infrared spectroscopy (FTIR). © 2014 IOP Publishing Ltd.

  4. Characteristics of Thermally Reduced Graphene Oxide Thin Film as DSSC Counter Electrode

    Science.gov (United States)

    Yuliasari, F.; Aprilia, A.; Syakir, N.; Safriani, L.; Saragi, T.; Risdiana; Hidayat, S.; Bahtiar, A.; Siregar, R.; Fitrilawati

    2017-05-01

    We report characteristics of reduced graphene oxide (RGO) as a counter electrode for dye-sensitized solar cell (DSSC). The RGO thin films were prepared on FTO (Fluorine-doped Tin Oxide) substrates and followed by a reduction process. The RGO film was used as a counter electrode in a DSSC device, with a structure of FTO/TiO2/ruthenium dye/mosalyte/RGO/FTO. UV-Vis measurements show an increasing absorption spectrum of RGO film after thermal reduction process and the FT-IR spectrum confirms a removal of the oxygen containing groups after thermal reduction process. The efficiency (η) of the DSSC that applied RGO film as a counter electrode is 0.96%.

  5. Plastic-based organic thin-film transistors with thermally cured polymeric gate dielectrics

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Gi-Heon; Yoon, Sung-Min; Kim, Chul-Am; Baek, Kyu-Ha; You, In-Kyu; Kang, Seong-Youl; Ahn, Seong-Deok; Suh, Kyung-Soo [Electronics and Telecommunications Research Institute, Daejeon (Korea, Republic of)

    2006-09-15

    In this investigation, we synthesized thermally curable polymers by mixing poly(vinyl phenol) (PVP) and a thermal-crosslinking agent (a methylated melamine-formaldehyde, MMF). These polymeric insulating films exhibit good chemical, physical, and electrical properties as dielectrics. Their insulating and dielectric properties depend on the MMF concentration. We fabricated plastic-based organic thin-film transistors (OTFTs) with these dielectric layers to investigate the relationship between the performance of the OTFT and the electrical/chemical properties of these insulating films. The OTFT showed good electrical performance; the field-effect mobility was 1.1 cm{sup 2}V{sup -1}s{sup -1}. A dielectric layer with a relatively low dielectric constant was found to give a higher field-effect mobility.

  6. Thermal Molding of Organic Thin-Film Transistor Arrays on Curved Surfaces

    Science.gov (United States)

    Sakai, Masatoshi; Watanabe, Kento; Ishimine, Hiroto; Okada, Yugo; Yamauchi, Hiroshi; Sadamitsu, Yuichi; Kudo, Kazuhiro

    2017-05-01

    In this work, a thermal molding technique is proposed for the fabrication of plastic electronics on curved surfaces, enabling the preparation of plastic films with freely designed shapes. The induced strain distribution observed in poly(ethylene naphthalate) films when planar sheets were deformed into hemispherical surfaces clearly indicated that natural thermal contraction played an important role in the formation of the curved surface. A fingertip-shaped organic thin-film transistor array molded from a real human finger was fabricated, and slight deformation induced by touching an object was detected from the drain current response. This type of device will lead to the development of robot fingers equipped with a sensitive tactile sense for precision work such as palpation or surgery.

  7. Thermal Characteristics of Multilayer Insulation Materials for Flexible Thin-Film Solar Cell Array of Stratospheric Airship

    Directory of Open Access Journals (Sweden)

    Kangwen Sun

    2014-01-01

    Full Text Available Flexible thin-film solar cell is an efficient energy system on the surface of stratospheric airship for utilizing the solar energy. In order to ensure the normal operation of airship platform, the thermal control problem between the flexible thin-film solar cell and the airship envelope should be properly resolved. In this paper, a multilayer insulation material (MLI is developed first, and low temperature environment test is carried out to verify the insulation effect of MLI. Then, a thermal heat transfer model of flexible thin-film solar cell and MLI is proposed, and the equivalent thermal conductivity coefficients of flexible thin-film solar cell and Nomex honeycomb are calculated based on the environment test and the temperature profile of flexible thin-film solar cell versus each layer of MLI. Finally, FLUENT is used for modeling and simulation analysis on the flexible thin-film solar cell and MLI, and the simulation results agree well with the experimental data, which validate the correctness of the proposed heat transfer model of MLI. In some way, our study can provide helpful support for further engineering applications of flexible thin-film solar cell.

  8. A micromachined thermally compensated thin film Lamb wave resonator for frequency control and sensing applications

    Science.gov (United States)

    Wingqvist, G.; Arapan, L.; Yantchev, V.; Katardjiev, I.

    2009-03-01

    Micromachined thin film plate acoustic wave resonators (FPARs) utilizing the lowest order symmetric Lamb wave (S0) propagating in highly textured 2 µm thick aluminium nitride (AlN) membranes have been successfully demonstrated (Yantchev and Katardjiev 2007 IEEE Trans. Ultrason. Ferroelectr. Freq. Control 54 87-95). The proposed devices have a SAW-based design and exhibit Q factors of up to 3000 at a frequency around 900 MHz as well as design flexibility with respect to the required motional resistance. However, a notable drawback of the proposed devices is the non-zero temperature coefficient of frequency (TCF) which lies in the range -20 ppm K-1 to -25 ppm K-1. Thus, despite the promising features demonstrated, further device optimization is required. In this work temperature compensation of thin AlN film Lamb wave resonators is studied and experimentally demonstrated. Temperature compensation while retaining at the same time the device electromechanical coupling is experimentally demonstrated. The zero TCF Lamb wave resonators are fabricated onto composite AlN/SiO2 membranes. Q factors of around 1400 have been measured at a frequency of around 755 MHz. Finally, the impact of technological issues on the device performance is discussed in view of improving the device performance.

  9. Tungsten oxide thin films grown by thermal evaporation with high resistance to leaching

    Energy Technology Data Exchange (ETDEWEB)

    Correa, Diogo S. [Universidade Federal de Pelotas (UFPel), RS (Brazil). Centro de Ciencias Quimicas, Farmaceuticas e de Alimentos; Pazinato, Julia C.O.; Freitas, Mauricio A. de; Radtke, Claudio; Garcia, Irene T.S., E-mail: irene@iq.ufrgs.br [Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, RS (Brazil). Instituto de Quimica; Dorneles, Lucio S. [Universidade Federal de Santa Maria (UFSM), RS (Brazil). Centro de Ciencias Naturais e Exatas

    2014-05-15

    Tungsten oxides show different stoichiometries, crystal lattices and morphologies. These characteristics are important mainly when they are used as photocatalysts. In this work tungsten oxide thin films were obtained by thermal evaporation on (100) silicon substrates covered with gold and heated at 350 and 600 °C, with different deposition times. The stoichiometry of the films, morphology, crystal structure and resistance to leaching were characterized through X-ray photoelectron spectroscopy, micro-Raman spectroscopy, scanning and transmission electron microscopy, X-ray diffractometry, Rutherford backscattering spectrometry and O{sup 16} (α,α')O{sup 16} resonant nuclear reaction. Films obtained at higher temperatures show well-defined spherical nanometric structure; they are composed of WO{sub 3.1} and the presence of hydrated tungsten oxide was also observed. The major crystal structure observed is the hexagonal. Thin films obtained through thermal evaporation present resistance to leaching in aqueous media and excellent performance as photocatalysts, evaluated through the degradation of the methyl orange dye. (author)

  10. Thermal-hydraulic analysis under partial loss of flow accident hypothesis of a plate-type fuel surrounded by two water channels using RELAP5 code

    Directory of Open Access Journals (Sweden)

    Itamar Iliuk

    2016-01-01

    Full Text Available Thermal-hydraulic analysis of plate-type fuel has great importance to the establishment of safety criteria, also to the licensing of the future nuclear reactor with the objective of propelling the Brazilian nuclear submarine. In this work, an analysis of a single plate-type fuel surrounding by two water channels was performed using the RELAP5 thermal-hydraulic code. To realize the simulations, a plate-type fuel with the meat of uranium dioxide sandwiched between two Zircaloy-4 plates was proposed. A partial loss of flow accident was simulated to show the behavior of the model under this type of accident. The results show that the critical heat flux was detected in the central region along the axial direction of the plate when the right water channel was blocked.

  11. Vibration analysis of an axially moving multiscale composite plate subjected to thermal loading

    Directory of Open Access Journals (Sweden)

    Marynowski Krzysztof

    2018-01-01

    Full Text Available This study investigated the effects of temperature on free vibrations and critical transport speeds of an axially moving multiscale composite plate. On the basis of the frequency-temperature equivalence principle, a linear mathematical model of the moving multiscale composite plate is derived in the complex frequency domain. Fractional standard rheological model of the plate material as the function of reduced frequency depended on the temperature is determined. In numerical investigations carbon nanotubes- and graphene-reinforced copper plate was taken into account.. To describe thermomechanical properties of the plate material, the investigation results obtained from the molecular dynamics studies and the experimental characteristic of beryllium copper in low temperatures presented in literature is taken into account.. The effects of temperature, transport speed, and internal damping on natural frequencies and critical transport speed are analyzed. The critical transport speeds of the graphene-reinforced multiscale composite are higher than both carbon nanotubes-reinforced composite as well as the comparable copper alloy.

  12. Performance Characterisation of a Hybrid Flat-Plate Vacuum Insulated Photovoltaic/Thermal Solar Power Module in Subtropical Climate

    Directory of Open Access Journals (Sweden)

    Andrew Y. A. Oyieke

    2016-01-01

    Full Text Available A flat-plate Vacuum Insulated Photovoltaic and Thermal (VIPV/T system has been thermodynamically simulated and experimentally evaluated to assess the thermal and electrical performance as well as energy conversion efficiencies under a subtropical climate. A simulation model made of specified components is developed in Transient Systems (TRNSYS environment into which numerical energy balance equations are implemented. The influence of vacuum insulation on the system’s electrical and thermal yields has been evaluated using temperatures, current, voltage, and power flows over daily and annual cycles under local meteorological conditions. The results from an experiment conducted under steady-state conditions in Durban, South Africa, are compared with the simulation based on the actual daily weather data. The VIPV/T has shown improved overall and thermal efficiencies of 9.5% and 16.8%, respectively, while electrical efficiency marginally reduced by 0.02% compared to the conventional PV/T. The simulated annual overall efficiency of 29% (i.e., 18% thermal and 11% electrical has been realised, in addition to the solar fraction, overall exergy, and primary energy saving efficiencies of 39%, 29%, and 27%, respectively.

  13. Defect induced phonon scattering for tuning the lattice thermal conductivity of SiO2 thin films

    Directory of Open Access Journals (Sweden)

    Sen Cao

    2017-01-01

    Full Text Available In this work, the thermal properties of nanoscale SiO2 thin films have been systematically investigated with respect to the thickness, crystal orientations and the void defects using non-equilibrium molecular-dynamics (NEMD simulation. Size effect for the lattice thermal conductivity of nanoscale SiO2 thin films was observed. Additionally, SiO2 thin films with [001] oriented exhibited greater thermal conductivity compared with other crystal orientations which was discussed in terms of phonon density of states (PDOS. Furthermore, the porosity of void defects was introduced to quantify the influence of defects for thermal conductivity. Results exhibited that the thermal conductivity degraded with the increase of porosity. Two thermal conductivity suppression mechanisms, namely, void defects induced material loss interdicting heat conduction and phonon scattering enhanced by the boundary of defects, were proposed. Then, a further simulation was deployed to find that the effect of boundary scattering of defects was dominant in thermal conductivity degradation compared with material loss mechanism. The conclusion suggests that the thermal conductivity could be configured via regulating the distribution of PDOS directly associated with void defects.

  14. On Nonperturbative Techniques for Thermal Radiation Effect on Natural Convection past a Vertical Plate Embedded in a Saturated Porous Medium

    Directory of Open Access Journals (Sweden)

    R. J. Moitsheki

    2008-10-01

    Full Text Available In this article, the heat transfer characteristics of natural convection about a vertical permeable flat surface embedded in a saturated porous medium are studied by taking into account the thermal radiation effect. The plate is assumed to have a power-law temperature distribution. Similarity variables are employed in order to transform the governing partial differential equations into a nonlinear ordinary differential equation. Both Adomian decomposition method (ADM and He's variational iteration method (VIM coupled with Padé approximation technique are implemented to solve the reduced system. Comparisons with previously published works are performed, and excellent agreement between the results is obtained.

  15. Effects of thermal annealing on the magnetic interactions in nanogranular Fe-Ag thin films

    Energy Technology Data Exchange (ETDEWEB)

    Alonso, J.; Fdez-Gubieda, M.L.; Svalov, A. [Departamento de Electricidad y Electronica, Universidad del Pais Vasco (UPV/EHU), Campus de Leioa, 48940 Leioa (Spain); Meneghini, C. [Dipartimento di Fisica ' E. Amaldi' , Universita degli Studi Roma Tre, 00146 Roma (Italy); Orue, I. [SGIker, Universidad del Pais Vasco (UPV/EHU), Campus de Leioa, 48940 Leioa (Spain)

    2012-09-25

    Highlights: Black-Right-Pointing-Pointer Fe{sub x}Ag{sub 100-x} granular thin films with competing interactions (25 {<=} x{<=} 35). Black-Right-Pointing-Pointer Annealing up to 200 Degree-Sign C mainly modifies the interface of Fe nanoparticles. Black-Right-Pointing-Pointer Annealing reduces RKKY interactions in Fe{sub 25}Ag{sub 75}. Black-Right-Pointing-Pointer Annealing favors exchange interactions and ferromagnetic order in Fe{sub 35}Ag{sub 65}. - Abstract: In this paper we have studied, by analysing the evolution of the magnetic behaviour during thermal treatment, the role of the interparticle magnetic interactions in Fe{sub x}Ag{sub 100-x} granular thin films prepared by sputtering deposition technique. Two compositions have been selected: x = 25 and 35, below and around the magnetic percolation of the system, respectively, according to our previous works. The structure of these thin films has been studied by X-ray diffraction (XRD) and X-ray absorption spectroscopy (XAS) measurements. To analyse the magnetic behaviour, DC magnetic measurements have been carried out after progressively annealing the samples at different temperatures (0 {<=} T{sub ann} {<=} 200 Degree-Sign C). These measurements have revealed that, upon thermal treatment, the frustrated state at low temperatures (T < 80 K) for the x = 25 sample tends to disappear, probably due to the weakening of RKKY interactions after the segregation of soluted Fe atoms in the Ag matrix. However, dipolar interactions are not affected by the annealing. On the contrary, at x = 35, around the magnetic percolation, the annealing gives rise to an increasingly ordered interface, thereby enhancing the transfer of the direct exchange interactions.

  16. Organo-Chlorinated Thin Films Deposited by Atmospheric Pressure Plasma-Enhanced Chemical Vapor Deposition for Adhesion Enhancement between Rubber and Zinc-Plated Steel Monofilaments.

    Science.gov (United States)

    Vandenabeele, Cédric; Bulou, Simon; Maurau, Rémy; Siffer, Frederic; Belmonte, Thierry; Choquet, Patrick

    2015-07-08

    A continuous-flow plasma process working at atmospheric pressure is developed to enhance the adhesion between a rubber compound and a zinc-plated steel monofilament, with the long-term objective to find a potential alternative to the electrolytic brass plating process, which is currently used in tire industry. For this purpose, a highly efficient tubular dielectric barrier discharge reactor is built to allow the continuous treatment of "endless" cylindrical substrates. The best treatment conditions found regarding adhesion are Ar/O2 plasma pretreatment, followed by the deposition from dichloromethane of a 75 nm-thick organo-chlorinated plasma polymerized thin film. Ar/O2 pretreatment allows the removal of organic residues, coming from drawing lubricants, and induces external growth of zinc oxide. The plasma layer has to be preferably deposited at low power to conserve sufficient hydrocarbon moieties. Surface analyses reveal the complex chemical mechanism behind the establishment of strong adhesion levels, more than five times higher after the plasma treatment. During the vulcanization step, superficial ZnO reacts with the chlorinated species of the thin film and is converted into porous and granular bump-shaped ZnwOxHyClz nanostructures. Together, rubber additives diffuse through the plasma layer and lead to the formation of zinc sulfide on the substrate surface. Hence, two distinct interfaces, rubber/thin film and thin film/substrate, are established. On the basis of these observations, hypotheses explaining the high bonding strength results are formulated.

  17. Thermal stress analyses of a header plate with a 51-PIN electrical feed-thru

    Energy Technology Data Exchange (ETDEWEB)

    Bergmann, V.L.; McCollister, H.L.

    1992-12-31

    An electronic package currently under development requires a hermetically-sealed electrical connection through a metal header plate. The electrical feedthru consists of 51 RA333 pins in an S-type glass ceramic insulator. Because the feedthru contains a large number of pins spaced closely together, a single glass preform rather than individual glass beads at each pin has been proposed. Finite element analyses were conducted to gain insight into the stress distribution in the header plate, glass, and pins. To verify the finite element analyses, a prototype part was manufactured and examined for cracking in the glass ceramic and for leakage of the glass-to-metal seal. Finite element analyses were then used to investigate effects of the plate geometry and yield strength on stresses in the assembly. This paper illustrates one way that finite element analyses can be used along with selective prototype manufacturing for a timely and cost-effective method of evaluating design parameters of electronic packages.

  18. Spectral and angular-selective thermal emission from gallium-doped zinc oxide thin film structures

    Science.gov (United States)

    Sakr, Enas; Bermel, Peter

    2017-02-01

    Simultaneously controlling both the spectral and angular emission of thermal photons can qualitatively change the nature of thermal radiation, and offers a great potential to improve a broad range of applications, including infrared light sources and thermophotovoltaic (TPV) conversion of waste heat to electricity. For TPV in particular, frequency-selective emission is necessary for spectral matching with a photovoltaic converter, while directional emission is needed to maximize the fraction of emission reaching the receiver at large separation distances. This can allow the photovoltaics to be moved outside vacuum encapsulation. In this work, we demonstrate both directionally and spectrally-selective thermal emission for p-polarization, using a combination of an epsilon-near-zero (ENZ) thin film backed by a metal reflector, a high contrast grating, and an omnidirectional mirror. Gallium-doped zinc oxide is selected as an ENZ material, with cross-over frequency in the near-infrared. The proposed structure relies on coupling guided modes (instead of plasmonic modes) to the ENZ thin film using the high contrast grating. The angular width is thus controlled by the choice of grating period. Other off-directional modes are then filtered out using the omnidirectional mirror, thus enhancing frequency selectivity. Our emitter design maintains both a high view factor and high frequency selectivity, leading to a factor of 8.85 enhancement over a typical blackbody emitter, through a combination of a 22.26% increase in view factor and a 6.88x enhancement in frequency selectivity. This calculation assumes a PV converter five widths away from the same width emitter in 2D at 1573 K.

  19. NUMERICAL STUDY OF MICROPOLAR FLUID FLOW HEAT AND MASS TRANSFER OVER VERTICAL PLATE: EFFECTS OF THERMAL RADIATION AND MAGNETIC FIELD

    Directory of Open Access Journals (Sweden)

    REDHA ALOUAOUI

    2015-06-01

    Full Text Available In this paper, we examine the thermal radiation effect on heat and mass transfer in steady laminar boundary layer flow of an incompressible viscous micropolar fluid over a vertical flat plate, with the presence of a magnetic field. Rosseland approximation is applied to describe the radiative heat flux in the energy equation. The resulting similarity equations are solved numerically. Many results are obtained and representative set is displayed graphically to illustrate the influence of the various parameters on different profiles. The conclusion is drawn that the flow field, temperature, concentration and microrotation  as well as the skin friction coefficient and the both  local Nusselt and Sherwood numbers  are significantly influenced by Magnetic parameter, material parameter  and thermal radiation parameter.

  20. Parallel experimental study of a novel super-thin thermal absorber based photovoltaic/thermal (PV/T) system against conventional photovoltaic (PV) system

    OpenAIRE

    Xu, Peng; Zhang, Xingxing; Shen, Jingchun; Zhao, Xudong; He, Wei; Li, Deying

    2015-01-01

    Photovoltaic (PV) semiconductor degrades in performance due to temperature rise. A super thin-conductive thermal absorber is therefore developed to regulate the PV working temperature by retrofitting the existing PV panel into the photovoltaic/thermal (PV/T) panel. This article presented the parallel comparative investigation of the two different systems through both laboratory and field experiments. The laboratory evaluation consisted of one PV panel and one PV/T panel respectively while the...

  1. An On-Line Method for Thermal Diffusivity Detection of Thin Films Using Infrared Video

    Directory of Open Access Journals (Sweden)

    Dong Huilong

    2016-03-01

    Full Text Available A novel method for thermal diffusivity evolution of thin-film materials with pulsed Gaussian beam and infrared video is reported. Compared with common pulse methods performed in specialized labs, the proposed method implements a rapid on-line measurement without producing the off-centre detection error. Through mathematical deduction of the original heat conduction model, it is discovered that the area s, which is encircled by the maximum temperature curve rTMAX(θ, increases linearly over elapsed time. The thermal diffusivity is acquired from the growth rate of the area s. In this study, the off-centre detection error is avoided by performing the distance regularized level set evolution formulation. The area s was extracted from the binary images of temperature variation rate, without inducing errors from determination of the heat source centre. Thermal diffusivities of three materials, 304 stainless steel, titanium, and zirconium have been measured with the established on-line detection system, and the measurement errors are: −2.26%, −1.07%, and 1.61% respectively.

  2. Thermal, morphological and optical investigations of Cu(DAB){sub 2} thin films produced by matrix-assisted pulsed laser evaporation and laser-induced forward transfer for sensor development

    Energy Technology Data Exchange (ETDEWEB)

    Constantinescu, C., E-mail: catalin.constantinescu@inflpr.ro [INFLPR - National Institute for Laser, Plasma and Radiation Physics, PPAM - Lasers Department, 409 Atomistilor blvd., Magurele, RO-077125, Bucharest (Romania); Morintale, E. [INFLPR - National Institute for Laser, Plasma and Radiation Physics, PPAM - Lasers Department, 409 Atomistilor blvd., Magurele, RO-077125, Bucharest (Romania); University of Craiova, Faculty of Physics, 13 A.I. Cuza St., Craiova, RO-200585, Dolj (Romania); Ion, V.; Moldovan, A.; Luculescu, C.; Dinescu, M. [INFLPR - National Institute for Laser, Plasma and Radiation Physics, PPAM - Lasers Department, 409 Atomistilor blvd., Magurele, RO-077125, Bucharest (Romania); Rotaru, P. [University of Craiova, Faculty of Physics, 13 A.I. Cuza St., Craiova, RO-200585, Dolj (Romania)

    2012-03-30

    Many hybrid metal-organic complex materials which exhibit crystalline nature, nonlinear optical properties and chemoselective behavior generate interest as choice materials in various applications. In this paper we report results on Cu(II) 2,2 Prime -dihydroxyazobenzene thin films deposited on silicon and quartz substrates by matrix assisted pulsed laser evaporation using a Nd:YAG laser, at 266 and 355 nm laser wavelengths. Thermal analysis, atomic force microscopy, scanning electron microscopy and spectroscopic ellipsometry were performed in order to investigate thin film properties. Micrometric pixels of the compound have been transferred on glass plates by laser-induced forward transfer for chemoselective sensor development purposes. - Highlights: Black-Right-Pointing-Pointer Cu(II) 2,2'-dihydroxyazobenzene thin films were grown by MAPLE. Black-Right-Pointing-Pointer Thermal analysis was performed on both bulk and thin films. Black-Right-Pointing-Pointer Thin films were investigated by means of microscopy and spectroscopic-ellipsometry. Black-Right-Pointing-Pointer Micrometric pixels of the compound were transferred by LIFT.

  3. Estimate of thermal fatigue lifetime for the INCONEL 625lCF plate while exposed to concentrated solar radiation

    Directory of Open Access Journals (Sweden)

    Rojas-Morín, A.

    2011-04-01

    Full Text Available A system for testing the thermal cycling of materials and components has been developed and installed at the DISTAL-I parabolic dish facility located at the Plataforma Solar de Almería (PSA in Spain. This system allows us to perform abrupt heating/cooling tests by exposing central solar receiver materials to concentrated solar radiation. These tests are performed to simulate both the normal and critical operational conditions of the central solar receiver. The thermal fatigue life for the INCONEL 625LCF® plate when subjected to concentrated solar radiation has been estimated with this system. We have also developed a numerical model that evaluates the thermal behavior of the plate material; additionally, the model yields the tensile-compressive stresses on the plate, which allow the estimation of the Stress-Life (S-N fatigue curves. These curves show that the lifetime of the plate is within the High Cycle Fatigue (HCF region at the operational temperatures of both 650 °C and 900 °C.

    En el concentrador solar de disco parabólico DISTAL-I, situado en la Plataforma Solar de Almería (PSA, en España, se ha instalado un sistema para pruebas de ciclado térmico de materiales. Este sistema permite realizar pruebas abruptas de calentamiento y enfriamiento, en materiales para receptores solares de torre central, al exponerlos a radiación solar concentrada. Estas pruebas se realizan para simular las condiciones de operación de un receptor solar, las condiciones críticas y las condiciones normales. Con este sistema se ha estimado el tiempo de vida bajo fatiga térmica, en una placa de INCONEL 626LCF®, cuando es sometida a radiación solar concentrada. Asimismo, hemos desarrollado un modelo numérico que evalúa el desarrollo térmico en el material de la placa: adicionalmente, el modelo obtiene los esfuerzos de tensión-compresión en la placa, los cuales permiten la estimaciónde las curvas de fatiga vidaesfuerzo (S-N. Estas curvas

  4. Finite element modelling for thermal analysis of stud-to-plate laser brazing for a dissimilar metal joint

    Energy Technology Data Exchange (ETDEWEB)

    Park, Jun Soo; Kim, Jong Min [Korea Atomic Energy Research Institute, Taejon (Korea, Republic of)

    1996-06-01

    A finite element model was developed for the thermal analysis of a stud-to-plate laser brazing joint, and the transient temperature fields were analysed by using a three-dimensional model. The finite element program ABAQUS, together with a few user subroutines, was employed to perform the numerical approximation. Temperature-dependent thermal properties, effect of latent heat, and the convection and radiative heat losses were considered. The brazing parts used were AISI 304 stainless steel stud and aluminium A1 5052 plate, and the brazing alloy 88 A1-12 Si was used as filler metal. A pseudo-TM{sub 01} mode of the cw CO{sub 2} laser beam was used as heat source, for which TM{sub 00} mode generated by beam oscillator was optically modulated using axicon lens. Re-location of the filler metal during the brazing process including its wetting and spreading was examined by using a high speed motion analyser, and the results were incorporated inn the FEM modelling for defining the solution domain and boundary conditions. The numerical results were obtained for typical process parameters, and were compared with experimental ones determined by using the infrared and thermocouple measurements. 11 figs., 30 refs. (Author).

  5. Calibration of a thin metal foil for infrared imaging video bolometer to estimate the spatial variation of thermal diffusivity using a photo-thermal technique

    Energy Technology Data Exchange (ETDEWEB)

    Pandya, Shwetang N., E-mail: pandya.shwetang@LHD.nifs.ac.jp; Sano, Ryuichi [The Graduate University of Advanced Studies, 322-6 Oroshi-cho, Toki 509-5292 (Japan); Peterson, Byron J.; Mukai, Kiyofumi; Akiyama, Tsuyoshi; Watanabe, Takashi [National Institute for Fusion Science, 322-6 Oroshi-cho, Toki 509-5292 (Japan); Drapiko, Evgeny A. [Fusion Centre, 1, Akademika Kurchatova pl., Moscow 123182 (Russian Federation); Alekseyev, Andrey G. [Kurchatov Institute, 1, Akademika Kurchatova pl., Moscow 123182 (Russian Federation); Itomi, Muneji [Graduate School of Engineering, Hokkaido University, Kita-13, Nishi-8, Kita-ku, Sapporo 060-8628 (Japan)

    2014-05-15

    A thin metal foil is used as a broad band radiation absorber for the InfraRed imaging Video Bolometer (IRVB), which is a vital diagnostic for studying three-dimensional radiation structures from high temperature plasmas in the Large Helical Device. The two-dimensional (2D) heat diffusion equation of the foil needs to be solved numerically to estimate the radiation falling on the foil through a pinhole geometry. The thermal, physical, and optical properties of the metal foil are among the inputs to the code besides the spatiotemporal variation of temperature, for reliable estimation of the exhaust power from the plasma illuminating the foil. The foil being very thin and of considerable size, non-uniformities in these properties need to be determined by suitable calibration procedures. The graphite spray used for increasing the surface emissivity also contributes to a change in the thermal properties. This paper discusses the application of the thermographic technique for determining the spatial variation of the effective in-plane thermal diffusivity of the thin metal foil and graphite composite. The paper also discusses the advantages of this technique in the light of limitations and drawbacks presented by other calibration techniques being practiced currently. The technique is initially applied to a material of known thickness and thermal properties for validation and finally to thin foils of gold and platinum both with two different thicknesses. It is observed that the effect of the graphite layer on the estimation of the thermal diffusivity becomes more pronounced for thinner foils and the measured values are approximately 2.5–3 times lower than the literature values. It is also observed that the percentage reduction in thermal diffusivity due to the coating is lower for high thermal diffusivity materials such as gold. This fact may also explain, albeit partially, the higher sensitivity of the platinum foil as compared to gold.

  6. Calibration of a thin metal foil for infrared imaging video bolometer to estimate the spatial variation of thermal diffusivity using a photo-thermal technique.

    Science.gov (United States)

    Pandya, Shwetang N; Peterson, Byron J; Sano, Ryuichi; Mukai, Kiyofumi; Drapiko, Evgeny A; Alekseyev, Andrey G; Akiyama, Tsuyoshi; Itomi, Muneji; Watanabe, Takashi

    2014-05-01

    A thin metal foil is used as a broad band radiation absorber for the InfraRed imaging Video Bolometer (IRVB), which is a vital diagnostic for studying three-dimensional radiation structures from high temperature plasmas in the Large Helical Device. The two-dimensional (2D) heat diffusion equation of the foil needs to be solved numerically to estimate the radiation falling on the foil through a pinhole geometry. The thermal, physical, and optical properties of the metal foil are among the inputs to the code besides the spatiotemporal variation of temperature, for reliable estimation of the exhaust power from the plasma illuminating the foil. The foil being very thin and of considerable size, non-uniformities in these properties need to be determined by suitable calibration procedures. The graphite spray used for increasing the surface emissivity also contributes to a change in the thermal properties. This paper discusses the application of the thermographic technique for determining the spatial variation of the effective in-plane thermal diffusivity of the thin metal foil and graphite composite. The paper also discusses the advantages of this technique in the light of limitations and drawbacks presented by other calibration techniques being practiced currently. The technique is initially applied to a material of known thickness and thermal properties for validation and finally to thin foils of gold and platinum both with two different thicknesses. It is observed that the effect of the graphite layer on the estimation of the thermal diffusivity becomes more pronounced for thinner foils and the measured values are approximately 2.5-3 times lower than the literature values. It is also observed that the percentage reduction in thermal diffusivity due to the coating is lower for high thermal diffusivity materials such as gold. This fact may also explain, albeit partially, the higher sensitivity of the platinum foil as compared to gold.

  7. Silica-based monolithic sensing plates for waveguide-mode sensors

    National Research Council Canada - National Science Library

    Makoto Fujimaki; Carsten Rockstuhl; Xiaomin Wang; Koichi Awazu; Junji Tominaga; Yuuki Koganezawa; Yoshimichi Ohki; Tetsuro Komatsubara

    2008-01-01

    We developed a monolithic sensing plate for a waveguide-mode sensor. The plate consists of a SiO_2 glass substrate and a thin silicon layer the surface of which is thermally oxidized to form a SiO_2 glass waveguide...

  8. Hot Plate Annealing at a Low Temperature of a Thin Ferroelectric P(VDF-TrFE Film with an Improved Crystalline Structure for Sensors and Actuators

    Directory of Open Access Journals (Sweden)

    Rahman Ismael Mahdi

    2014-10-01

    Full Text Available Ferroelectric poly(vinylidene fluoride-trifluoroethylene (P(VDF-TrFE copolymer 70/30 thin films are prepared by spin coating. The crystalline structure of these films is investigated by varying the annealing temperature from the ferroelectric phase to the paraelectric phase. A hot plate was used to produce a direct and an efficient annealing effect on the thin film. The dielectric, ferroelectric and pyroelectric properties of the P(VDF-TrFE thin films are measured as a function of different annealing temperatures (80 to 140 °C. It was found that an annealing temperature of 100 °C (slightly above the Curie temperature, Tc has induced a highly crystalline β phase with a rod-like crystal structure, as examined by X-ray. Such a crystal structure yields a high remanent polarization, Pr = 94 mC/m2, and pyroelectric constant, p = 24 μC/m2K. A higher annealing temperature exhibits an elongated needle-like crystal domain, resulting in a decrease in the crystalline structure and the functional electrical properties. This study revealed that highly crystalline P(VDF-TrFE thin films could be induced at 100 °C by annealing the thin film with a simple and cheap method.

  9. Experimental testing of various heat transfer structures in a flat plate thermal energy storage unit

    OpenAIRE

    Johnson, Maike; Fiss, Michael; Klemm, Torsten

    2016-01-01

    For solar process heat applications with steam as the working fluid and varying application parameters, a novel latent heat storage concept has been developed using an adaptation of a flat plate heat exchanger as the storage concept. Since the pressure level in these applications usually does not exceed 30 bar, an adaptation with storage material chambers arranged between heat transfer medium chambers is possible. Phase change materials are used as the storage medium, so that the isotherma...

  10. Monitoring of a flat plate solar thermal field supplying process heat

    OpenAIRE

    Cozzini Marco; Fedrizzi Roberto; Pipiciello Mauro; Söll Robert; Ben Hassine Ilyes; Pietruschka Dirk

    2016-01-01

    The article reports the performance data of a flat plate collector field installed in Austria and supplying process heat to a meat factory, up to a temperature of about 95 °C. The presented data span an entire year, thereby including seasonal effects and allowing for a full characterization of the system performances. Sensor uncertainty is also discussed in detail. Finally, a bin method analysis of the field efficiency is provided. To this purpose, different operating conditions are concisely...

  11. Investigation of effect of annealing on thermally evaporated ZnSe thin films through spectroscopic techniques

    Science.gov (United States)

    Mahesha, M. G.; Rashmitha; Meghana, N.; Padiyar, Meghavarsha

    2017-09-01

    ZnSe thin films have been grown on clean glass substrates by thermal evaporation technique and deposited films have been annealed at 473 K. William-Hall method has been adopted to extract information on crystallite size and internal strain in the film from X-ray diffractogram. Effect of annealing on ZnSe films has been analyzed by spectroscopic techniques which include optical absorption, Raman, and photoluminescence spectroscopy. From optical absorption, band gap has been estimated along with other optical parameters like refractive index and extinction coefficient. Also, Urbach tail, which originates near bad edge due to structural disorders, has been characterized. Raman spectra have been analyzed to get the information on the influence of crystallite size and strain effect on peak position, intensity and width. Photoluminescence spectra have been recorded and analyzed to get an insight on defect levels induced due to vacancies, interstadials, and impurity complexes.

  12. Crystalline silicon surface passivation by thermal ALD deposited Al doped ZnO thin films

    Directory of Open Access Journals (Sweden)

    Jagannath Panigrahi

    2017-03-01

    Full Text Available The evidence of good quality silicon surface passivation using thermal ALD deposited Al doped zinc oxide (AZO thin films is demonstrated. AZO films are prepared by introducing aluminium precursor in between zinc and oxygen precursors during the deposition. The formation of AZO is confirmed by ellipsometry, XRD and Hall measurements. Effective minority carrier lifetime (τeff greater than 1.5ms at intermediate bulk injection levels is realized for symmetrically passivated p-type silicon surfaces under optimised annealing conditions of temperature and time in hydrogen ambient. The best results are realised at 450°C annealing for >15min. Such a layer may lead to implied open circuit voltage gain of 80mV.

  13. Thermal and Electrical Effects of Partial Shade in Monolithic Thin-Film Photovoltaic Modules: Preprint

    Energy Technology Data Exchange (ETDEWEB)

    Silverman, Timothy J.; Deceglie, Michael G.; Sun, Xingshu; Garris, Rebekah L.; Alam, Muhammad Ashraful; Deline, Chris; Kurtz, Sarah

    2015-09-02

    Photovoltaic cells can be damaged by reverse bias stress, which arises during service when a monolithically integrated thin-film module is partially shaded. We introduce a model for describing a module's internal thermal and electrical state, which cannot normally be measured. Using this model and experimental measurements, we present several results with relevance for reliability testing and module engineering: Modules with a small breakdown voltage experience less stress than those with a large breakdown voltage, with some exceptions for modules having light-enhanced reverse breakdown. Masks leaving a small part of the masked cells illuminated can lead to very high temperature and current density compared to masks covering entire cells.

  14. On the influence of thermal effects on the dynamics of thin films and filaments

    Science.gov (United States)

    Kondic, Lou; Seric, Ivana; Afkhami, Shahriar

    2017-11-01

    We report our recent progress on formulating fully self-consistent simulations the dynamics of thin films and filaments exposed to an external heat source on thermally conductive substrate. The simulations are based on the Volume of Fluid, and include novel components such as inclusion of Marangoni, as well as of van der Waals forces. Furthermore, the simulations couple dynamics directly with the spatio-temporal evolution of temperature field boththe fluid and in the substrate. The particular physical setup considered involvesfilms and geometries exposed to laser heating on silicon/silicon dioxide, with the focus on understanding the influence of variation of material (surface tension and viscosity) with temperature. We will discussrole that Marangoni effect has on the development of film instability, and willconsider the influence of variation of normal interfacial stresses due toevolution of the fluid temperature. Supported by NSF Grant No. CBET-1604351.

  15. Triple Plate Mold Final Report: Optimization of the Mold Design and Casting Parameters for a Thin U-10mo Fuel Casting

    Energy Technology Data Exchange (ETDEWEB)

    Aikin, Jr., Robert M. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2017-01-04

    This work describes the experiments and modeling that have been performed to improve and try to optimize the simultaneous casting of three plates of U-10wt%Mo in a single coil vacuum induction melting (VIM) furnace. The plates of interest are 280 mm wide by 203 mm tall by 5 mm thick (11" x 8" x 0.2"). The initial mold design and processing parameters were supplied by Y-12. The mold and casting cavity were instrumented with a number of thermocouples, and the casting performed to determine the thermal history of the mold and casting. The resulting cast plates were radiographed and numerous defects identified. Metallography was performed to help identify the nature of the radiographically observed defects. This information was then used to validate a mold filling and solidification model of that casting. Based on the initial casting, good casting design practice, and process simulation of several design alternatives, a revised design was developed with the goal of minimizing casting defects such as porosity. The redesigned mold had a larger hot-top and had its long axis along the horizontal direction. These changes were to try to develop a strong thermal gradient conducive to good feeding and minimization of micro- and macroporosity in the cast plates. An instrumented casting was then performed with the revised mold design and a linear distributor. This design yielded cast plates with significantly less radiographically identified defects. Unfortunately, there was significant variation in plate weight and metal content in their hot-tops. Fluid flow simulations were then performed on this mold/distributor design. This helped identify the issue with this linear distributor design. Additional simulations were then performed on candidate distributor redesigns and a preferred distributor annular design was identified. This improved annular design was used to produce a third instrumented casting with favorable results. These refined designs and their radiographic

  16. Alternative nano-structured thin-film materials used as durable thermal nanoimprint lithography templates.

    Science.gov (United States)

    Bossard, M; Boussey, J; Le Drogoff, B; Chaker, M

    2016-02-19

    Nanoimprint templates made of diamond-like carbon (DLC) and amorphous silicon carbide (SiC) thin films and fluorine-doped associated materials, i.e. F-DLC and F-SiC were investigated in the context of thermal nanoimprint lithography (NIL) with respect to their release properties. Their performances in terms of durability and stability were evaluated and compared to those of conventional silicon or silica molds coated with antisticking molecules applied as a self-assembled monolayer. Plasma-enhanced chemical vapor deposition parameters were firstly tuned to optimize mechanical and structural properties of the DLC and SiC thin films. The impact of the amount of fluorine dopant on the deposited thin films properties was then analyzed. A comparative analysis of DLC, F-DLC as well as SiC and F-SiC molds was then carried out over multiple imprints, performed into poly (methyl methacrylate) (PMMA) thermo-plastic resist. The release properties of un-patterned films were evaluated by the measurement of demolding energies and surface energies, associated with a systematic analysis of the mold surface contamination. These analyses showed that the developed materials behave as intrinsically easy-demolding and contamination-free molds over series of up to 40 imprints. To our knowledge, it is the first time that such a large number of imprints has been considered within an exhaustive comparative study of materials for NIL. Finally, the developed materials went through standard e-beam lithography and plasma etching processes to obtain nanoscale-patterned templates. The replicas of those patterned molds, imprinted into PMMA, were shown to be of high fidelity and good stability after several imprints.

  17. Thermal stability of Fe16N2 thin film on GaAs (0 0 1) substrate

    Science.gov (United States)

    Zhang, Xiaowei; Lauter, Valeria; Ambaye, Haile; Wang, Jian-Ping

    2017-06-01

    There is a major need for a high performance magnetic system for high temperature applications. One propitious low cost permanent magnet candidate is Fe16N2, with its giant magnetic moment predicted to be above other materials from conventional first principles calculations. Here we report on a comprehensive study of the thermal stability of Fe16N2 thin films on GaAs (0 0 1) substrate. Using polarized neutron reflectometry (PNR), the saturation magnetization depth profile (Ms) of the films and its modification with temperature is directly measured at various thermal conditions. The structural modifications probed by x-ray diffraction (XRD) unravel that above 250 °C the Fe16N2 thin films decompose into α-Fe and γ‧-Fe4N phases. An influence of the strain effect is investigated by grazing incidence x-ray diffraction (GIXRD). We reveal that despite a large Fe16N2 in-plane lattice constant of ~5.88 Å and different strains from substrate or seed layer (up to 2.8% tensile strain), Fe16N2 thin films have the same thermal stability. Our results demonstrate that the high thermal stability of partially order Fe16N2 thin films makes them very promising candidates for spintronics and permanent magnet applications.

  18. The effect of thermal annealing on the properties of thin alumina films prepared by low pressure MOCVD

    NARCIS (Netherlands)

    Haanappel, V.A.C.; Haanappel, V.A.C.; van de Vendel, D.; van Corbach, H.D.; Fransen, T.; Gellings, P.J.

    1995-01-01

    Thin amorphous alumina films were prepared on stainless steel, type AISI 304, by low pressure metal-organic chemical vapour deposition. The effect of thermal annealing in nitrogen (for 2, 4 and 17 h at 600, 700 and 800 °C) on the film properties, including the protection of the underlying substrate

  19. Thin films of spin-crossover coordination polymers with large thermal hysteresis loops prepared by nanoparticle spin coating.

    Science.gov (United States)

    Tanaka, Daisuke; Aketa, Naoki; Tanaka, Hirofumi; Tamaki, Takashi; Inose, Tomoko; Akai, Tomoki; Toyama, Hirotaka; Sakata, Osami; Tajiri, Hiroo; Ogawa, Takuji

    2014-09-11

    This communication describes the synthesis of spin-crossover nanoparticles, which can disperse in various organic solvents without an excess amount of surfactants. The nanoparticles form homogeneous thin films on substrates by spin coating. The films show abrupt spin transitions with large thermal hysteresis loops.

  20. Measurement of the Thermal Properties of Prototype Lambda Plates for the LHC

    CERN Document Server

    Marie, R; Perin, A; Rieubland, Jean Michel

    2005-01-01

    In order to power the LHC superconducting magnets, thousands of busbars will be routed from electrical feedboxes containing saturated helium at 4.5 K to magnets operating in pressurized superfluid helium at 1.9 K. Between those two volumes, the busbars will pass through special feedthroughs also called lambdaplates. This article presents heat flow measurements performed on several configurations of vertical prototype lambda-plates feedthroughs. The results show that the heat flow is strongly influenced by the configuration of the busbar insulation in the saturated helium.

  1. Monitoring of a flat plate solar thermal field supplying process heat

    Directory of Open Access Journals (Sweden)

    Cozzini Marco

    2016-01-01

    Full Text Available The article reports the performance data of a flat plate collector field installed in Austria and supplying process heat to a meat factory, up to a temperature of about 95 °C. The presented data span an entire year, thereby including seasonal effects and allowing for a full characterization of the system performances. Sensor uncertainty is also discussed in detail. Finally, a bin method analysis of the field efficiency is provided. To this purpose, different operating conditions are concisely represented by the so-called reduced temperature, typically used in solar collector applications.

  2. Synthesis and characterization of polyimide thin films obtained by thermal evaporation and solid state reaction

    Directory of Open Access Journals (Sweden)

    Al-Ajaj Ikram Atta

    2016-03-01

    Full Text Available In this research polyimide films were prepared by physical vapor deposition (PVD, using solid state reaction of pyromellitic dianhydride (PMDA and p-phenylene diamine (PDA to form poly(amic acid (PAA films. The resultant films were converted to polyimide by thermal treatment, usually below 300 °C. For this study, a FT-IR spectrometer has been used to measure the effect of imidization temperature on the chemical structure of the vapor-deposited thin films of aromatic PI. When temperature increased, an increase in all absorption peaks was observed. This suggests that residual PAA monomers continued to be converted into PI. The surface topology of the PI films obtained at imidization temperatures of 150, 200, 250 °C for 1 hour was further examined by using AFM atomic force microscopy. It can be clearly seen that the surface became rougher with increasing imidization temperature. The thermal stability of polyimide was also studied by using thermogravimetric analysis (TGA.

  3. Mount Protects Thin-Walled Glass or Ceramic Tubes from Large Thermal and Vibration Loads

    Science.gov (United States)

    Amato, Michael; Schmidt, Stephen; Marsh. James; Dahya, Kevin

    2011-01-01

    The design allows for the low-stress mounting of fragile objects, like thin walled glass, by using particular ways of compensating, isolating, or releasing the coefficient of thermal expansion (CTE) differences between the mounted object and the mount itself. This mount profile is lower than true full kinematic mounting. Also, this approach enables accurate positioning of the component for electrical and optical interfaces. It avoids the higher and unpredictable stress issues that often result from potting the object. The mount has been built and tested to space-flight specifications, and has been used for fiber-optic, optical, and electrical interfaces for a spaceflight mission. This mount design is often metal and is slightly larger than the object to be mounted. The objects are optical or optical/electrical, and optical and/or electrical interfaces are required from the top and bottom. This requires the mount to be open at both ends, and for the object s position to be controlled. Thin inside inserts at the top and bottom contact the housing at defined lips, or edges, and hold the fragile object in the mount. The inserts can be customized to mimic the outer surface of the object, which further reduces stress. The inserts have the opposite CTE of the housing material, partially compensating for the CTE difference that causes thermal stress. A spring washer is inserted at one end to compensate for more CTE difference and to hold the object against the location edge of the mount for any optical position requirements. The spring also ensures that any fiber-optic or optic interface, which often requires some pressure to ensure a good interface, does not overstress the fragile object. The insert thickness, material, and spring washer size can be traded against each other to optimize the mount and stresses for various thermal and vibration load ranges and other mounting requirements. The alternate design uses two separate, unique features to reduce stress and hold the

  4. Effects of internal heat generation, thermal radiation and buoyancy force on a boundary layer over a vertical plate with a convective surface boundary condition

    OpenAIRE

    Tasawar Hayat; Awatif A. Hendi; Jacob A. Gbadeyan; Philip O. Olanrewaju

    2011-01-01

    In this paper we analyse the effects of internal heat generation, thermal radiation and buoyancy force on the laminar boundary layer about a vertical plate in a uniform stream of fluid under a convective surface boundary condition. In the analysis, we assumed that the left surface of the plate is in contact with a hot fluid whilst a stream of cold fluid flows steadily over the right surface; the heat source decays exponentially outwards from the surface of the plate. The similarity variable m...

  5. Broadband Dielectric Spectroscopic Characterization of Thermal Stability of Low-k Dielectric Thin Films for Micro- and Nanoelectronic Applications.

    Science.gov (United States)

    Sunday, Christopher E; Montgomery, Karl R; Amoah, Papa K; Obeng, Yaw S

    2017-01-01

    In this paper, we discuss the use of broadband microwaves (MW) to characterize the thermal stability of organic and hybrid silicon-organic thin films meant for insulation applications in micro- and nanoelectronic devices. We take advantage of MW propagation characteristics to extract and examine the relationships between electrical properties and the chemistry of prototypical low-k materials. The impact of thermal anneal at modest temperatures is examined to shed light on the thermal-induced performance and reliability changes within the dielectric films. These changes are then correlated with the chemical changes in the films, and could provide basis for rational selection of organic dielectrics for integrated devices.

  6. Experimental testing of various heat transfer structures in a flat plate thermal energy storage unit

    Science.gov (United States)

    Johnson, Maike; Fiß, Michael; Klemm, Torsten

    2016-05-01

    For solar process heat applications with steam as the working fluid and varying application parameters, a novel latent heat storage concept has been developed using an adaptation of a flat plate heat exchanger as the storage concept. Since the pressure level in these applications usually does not exceed 30 bar, an adaptation with storage material chambers arranged between heat transfer medium chambers is possible. Phase change materials are used as the storage medium, so that the isothermal evaporation of steam during discharging of the storage is paired with the isothermal solidification of the storage material. Heat transfer structures can be inserted into the chambers to adjust the power level for a given application. By combining the required number of flat plate heat exchanger compartments and inserting the appropriate heat transfer structure, the design can easily be adjusted for the required power level and capacity for a specific application. Within this work, the technical feasibility of this concept is proven. The dependence of the operating characteristics on the geometry of the heat exchanger is identified. A focus is on varying the power density by integrating conductive heat structures in the PCM.

  7. Three-dimensionally printed personalized guide plate for percutaneous radiofrequency thermal coagulation in idiopathic trigeminal neuralgia.

    Science.gov (United States)

    Deng, M; Cai, H; Fang, W; Long, X

    2018-03-01

    Radiofrequency thermocoagulation (RFT) is used widely for the treatment of idiopathic trigeminal neuralgia (TN). Precise puncture and placement of the electrode needle tip are crucial for successful RFT. This technical note introduces a novel method for performing RFT using a customized, three-dimensionally (3D)-printed guide plate. Eleven patients with idiopathic TN were treated using this method between February and July 2016. Three had V2 branch TN and eight had V3 branch TN. Punctures in eight patients were successful at the first attempt; slight adjustments were required subsequently in the other three patients. The puncture time in all cases was less than 1min. The patients reported pain relief immediately after RFT, and no complications were observed in any patient. Thus, the customized 3D-printed guide plate offers the advantages of precise placement of the puncture needle and minimal complications. Copyright © 2017 International Association of Oral and Maxillofacial Surgeons. Published by Elsevier Ltd. All rights reserved.

  8. Thin-layer infrared spectroscopic study on thermal behavior of non-phospholipid lipids and nanovesicles

    Science.gov (United States)

    Bista, Rajan K.; Bruch, Reinhard F.; Covington, Aaron M.

    2009-02-01

    °The investigation of thermal behaviors and subsequent changes in the conformational order of lipids and liposomes is of importance in understanding various phenomena such as the formation and fusion of vesicles, trans-membrane diffusion and membrane interactions with drugs and proteins. In this work, the thermal behavior of a suite of newly developed self-forming synthetic non-phospholipid (PEGylated) lipids and its nanovesicles in buffer suspensions were investigated by variable-temperature thin-layered Fourier Transform Infrared (FTIR) transmission spectroscopy. The temperature-induced infrared spectra of such lipids composed of 1,2-dimyristoyl-rac-glycerol-3-dodecaethylene glycol (GDM-12) and 1,2-distearoyl-rac-glycerol-3-triicosaethylene glycol (GDS-23) were acquired by using FTIR spectrometer in conjunction with a custom built temperature-controlled demountable liquid cell. In contrast to conventional phospholipids, these novel lipids form liposomes spontaneously upon hydration, without the supply of external activation energy. It was found that the thermal stability of the PEGylated lipids defer greatly depending upon the acyl chain-lengths as well as number of associated head group units. Particularly, GDM-12 (saturated 14 hydrocarbon chains) shows one sharp order-disorder transition with temperature increasing from 3 to 5 °C. Similarly, GDS-23 (saturated 18 hydrocarbon chains) exhibits comparatively broad order-disorder transition profiles between temperature 17 and 22 °C. However, the phase transition temperature becomes significantly higher for lipid nanovesicles formed in aqueous suspensions. The results obtained in this study may find applications in various areas including the development of lipid based substance and drug delivery systems.

  9. Analytical Thermal and Cost Optimization of Micro-Structured Plate-Fin Heat Sink

    DEFF Research Database (Denmark)

    Rezaniakolaei, Alireza; Rosendahl, Lasse

    sizes of the substrate plat of the heat sink. Results show that, at any pumping power there are specific values of the channel width and fin thickness which produce minimum thermal resistance in the heat sink. The results also illustrate that, a larger channel width and a smaller fin thickness lead...

  10. 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.

  11. Effect of Friction Stir Process Parameters on the Mechanical and Thermal Behavior of 5754-H111 Aluminum Plates.

    Science.gov (United States)

    Serio, Livia Maria; Palumbo, Davide; De Filippis, Luigi Alberto Ciro; Galietti, Umberto; Ludovico, Antonio Domenico

    2016-02-23

    A study of the Friction Stir Welding (FSW) process was carried out in order to evaluate the influence of process parameters on the mechanical properties of aluminum plates (AA5754-H111). The process was monitored during each test by means of infrared cameras in order to correlate temperature information with eventual changes of the mechanical properties of joints. In particular, two process parameters were considered for tests: the welding tool rotation speed and the welding tool traverse speed. The quality of joints was evaluated by means of destructive and non-destructive tests. In this regard, the presence of defects and the ultimate tensile strength (UTS) were investigated for each combination of the process parameters. A statistical analysis was carried out to assess the correlation between the thermal behavior of joints and the process parameters, also proving the capability of Infrared Thermography for on-line monitoring of the quality of joints.

  12. Effect of Friction Stir Process Parameters on the Mechanical and Thermal Behavior of 5754-H111 Aluminum Plates

    Science.gov (United States)

    Serio, Livia Maria; Palumbo, Davide; De Filippis, Luigi Alberto Ciro; Galietti, Umberto; Ludovico, Antonio Domenico

    2016-01-01

    A study of the Friction Stir Welding (FSW) process was carried out in order to evaluate the influence of process parameters on the mechanical properties of aluminum plates (AA5754-H111). The process was monitored during each test by means of infrared cameras in order to correlate temperature information with eventual changes of the mechanical properties of joints. In particular, two process parameters were considered for tests: the welding tool rotation speed and the welding tool traverse speed. The quality of joints was evaluated by means of destructive and non-destructive tests. In this regard, the presence of defects and the ultimate tensile strength (UTS) were investigated for each combination of the process parameters. A statistical analysis was carried out to assess the correlation between the thermal behavior of joints and the process parameters, also proving the capability of Infrared Thermography for on-line monitoring of the quality of joints. PMID:28773246

  13. Investigation of thermal behaviour, pressure drop, and pumping power in a Cu nanofluid-filled solar flat-plate collector

    Directory of Open Access Journals (Sweden)

    Shamshirgaran S. Reza

    2017-01-01

    Full Text Available The evaluations of the performance of solar flat-plate collectors are reported in the literature. A computer program developed by MATLAB has been applied for modelling the performance of a solar collector under steady state laminar conditions. Results demonstrate that Cu-water nanofluid would be capable of boosting the thermal efficiency of the collector by 2.4% at 4% volume concentration in the case of using Cunanofluid instead of just water as the working fluid. It is noteworthy that, dispersing the nanoparticles into the water results in a higher pressure drop and, therefore, a higher power consumption for pumping the nanofluid within the collector. It has been estimated for the collector understudy, that the increase in the pressure drop and pumping power to be around 30%.

  14. Investigation of Thermal Performance of Flat Plate and Evacuated Tubular Solar Collectors According to a New Dynamic Test Method

    DEFF Research Database (Denmark)

    Kong, Weiqiang; Wang, Zhifeng; Fan, Jianhua

    2012-01-01

    A new dynamic test method is introduced. This so called improved transfer function method features on two new collector parameters. One is time term which can indicate solar collector's inner heat transfer ability and the other is a second order term of collector mean fluid temperature which can...... obtain fluid thermal capacitance in data processing. Then theoretical analysis and experimental verification are carried out to investigate influencing factors of obtaining accurate and stable second order term. A flat plate and ETC solar collector are compared using both the new dynamic method...... and a standard method. The results show that the improved function method can accurately and robustly estimate these two kinds of solar collectors....

  15. Thermal radiation and mass transfer effects on unsteady MHD free convection flow past a vertical oscillating plate

    Science.gov (United States)

    Rana, B. M. Jewel; Ahmed, Rubel; Ahmmed, S. F.

    2017-06-01

    Unsteady MHD free convection flow past a vertical porous plate in porous medium with radiation, diffusion thermo, thermal diffusion and heat source are analyzed. The governing non-linear, partial differential equations are transformed into dimensionless by using non-dimensional quantities. Then the resultant dimensionless equations are solved numerically by applying an efficient, accurate and conditionally stable finite difference scheme of explicit type with the help of a computer programming language Compaq Visual Fortran. The stability and convergence analysis has been carried out to establish the effect of velocity, temperature, concentration, skin friction, Nusselt number, Sherwood number, stream lines and isotherms line. Finally, the effects of various parameters are presented graphically and discussed qualitatively.

  16. Flat sources for active acoustic shielding based on distributed control of a vibrating plate coupled with a thin cavity

    OpenAIRE

    Berkhoff, Arthur P.; Ho, J.

    2013-01-01

    Air cavities between plates are often used to improve noise insulation by passive means, especially at high frequencies. Such configurations may suffer from resonances, such as due to the mass-air-mass resonance. Lightweight structures, which tend to be undamped, may suffer from structural resonances as well. Active methods have been suggested for improved noise insulation of plates, using piezoelectric patch actuators or inertial mass actuators. Other active methods for improved noise insula...

  17. Deformation and Rupture of Thin Steel Plates due to Cumulative Loading from Underwater Shock and Bubble Collapse

    Directory of Open Access Journals (Sweden)

    Julian J. Lee

    2011-01-01

    Full Text Available The damage sustained by rigidly-clamped square steel plates when subjected to close-proximity underwater explosions has been investigated. The test specimens consisted of plates 0.76 mm and 1.21 mm thick made of either ASTM A1008 mild steel or 350 WT structural-grade steel with a low-temperature notch-toughness requirement. The explosively-loaded area of the plates was square, with dimensions of 254 mm X 254 mm. High-explosive charges from 1.1 g to 50 g were used at different standoff distances to obtain different shock strengths and bubble collapse intensities. Although the main impulsive load on the plate was due to the shock impact, because the standoff distances were less than twice the maximum free-field bubble radius, a strong interaction between the detonation product bubble and the target plate caused a rapid water jet to impinge on the plate, resulting in additional loading and damage. As a result, four main regimes of loading and damage were identified: a holing/petaling due to shock loading, b edge tearing due to shock loading only, c edge tearing due to the cumulative loading from shock and bubble collapse, and d large deformation due to shock and bubble collapse loading. The damage mechanisms and dynamic response of the plates were measured using dynamic displacement sensors, pressure gauges, and high-speed video. A fracture analysis was performed on the damaged plates to analyze the mechanisms of failure. Finally, finite-element analysis using a failure criterion based on normalized shear stress and effective strain has been used to examine the failure limits.

  18. Real-time simulation of thermal stresses and creep in plates subjected to transient heat input

    DEFF Research Database (Denmark)

    Hattel, Jesper Henri; Jacobsen, Torben Krogsdal; Hansen, P.N.

    1997-01-01

    -difference approach. It applies a general formulation which takes into account nonconstant material properties (e.g. temperature, material, or time dependency), heat-transfer coefficients, and creep. The temperature calculation applies a one-dimensional numerical model, whereas the stress analysis is semi......This paper presents a novel numerical technique for solving the temperature and stress fields in a plate subjected to arbitrarily varying transient boundary conditions (transient temperature and heat-flux variations) on a surface. The numerical method is based on the control-volume finite......-two-dimensional. Both plane stress and plane strain conditions are considered as extreme cases. It is shown that, by using the developed numerical technique, very fast real-time simulations can be performed. The method has proved its applicability in e.g. high-pressure die-casting, and applications to this industrial...

  19. Development of ion-plated aluminide diffusion coatings for thermal cyclic oxidation and hot corrosion protection of a nickel-based superalloy and a stainless steel

    Science.gov (United States)

    Elsawy, Abdel Raouf

    This project was carried out at the University of Toronto and Cametoid Ltd of Whitby, Ontario. Ohno continuous casting; a novel net shape casting technique, was used to generate, Al-Y, Al-Ce, Al-La, and Al-Si-Y, in form of 1.6 to 1.7 mm diameter alloy wires. These alloy wires exhibited suitable properties for use as feed materials to an Ion Vapor Deposition facility. The deposition parameters were optimized to provide coatings with a compact and cohesive columnar structure with reduced porosity and diffusion barriers that were essential to ensure the success of the diffusion process in the subsequent stage. Solid-state diffusion heat treatment processes were developed in order to form the stable aluminide phases, AlNi and FeAl, on IN738 and S310 substrates, respectively. Experiments simulating the coating service conditions and environments encountered during the prospective aerospace and fuel cell applications were conducted to evaluate the performance of each aluminide coating developed during this study. Thermal cyclic oxidation and molten sulfate corrosion studies were performed on coated IN738 pins at 1050°C and 900°C, respectively, simulating the service environment of turbine engine blades and other hot section components. Molten carbonate corrosion behavior was investigated for coated S310 coupons that were immersed in, or covered with a thin film of molten carbonate, at 650°C, in air plus 30%CO2, to simulate the operating conditions of the cathode-side separator plates of molten carbonate fuel cells. The behavior of the reactive elements, yttrium, cerium, lanthanum, and silicon in enhancing the adhesion of the protective aluminum oxide scale was determined by weight variation experiments, structural examination and compositional analysis. The influence of the base material elements, nickel, chromium, and iron, on the formation of protective oxides was investigated. All coatings were found to provide significant improvement for thermal cyclic oxidation

  20. Determination of elastic and thermal properties of a thin nanocrystalline diamond coating using all-optical methods

    Energy Technology Data Exchange (ETDEWEB)

    Sermeus, J.; Verstraeten, B.; Salenbien, R. [KU Leuven-University of Leuven, Soft Matter and Biophysics, Celestijnenlaan 200D, B-3001 Heverlee (Belgium); Pobedinskas, P.; Haenen, K. [Instituut voor Materiaalonderzoek (IMO), Hasselt University, Wetenschapspark 1, 3590 Diepenbeek (Belgium); IMOMEC, IMEC vzw, Wetenschapspark 1, 3590 Diepenbeek (Belgium); Glorieux, C., E-mail: christ.glorieux@fys.kuleuven.be [KU Leuven-University of Leuven, Soft Matter and Biophysics, Celestijnenlaan 200D, B-3001 Heverlee (Belgium)

    2015-09-01

    Results are presented on the thermal and elastic properties of a thin, 1.5 μm, nanocrystalline diamond coating (NCD), deposited on a silicon substrate by microwave plasma enhanced chemical vapor deposition. A combination of two all-optical measurement techniques, impulsive stimulated thermal scattering and grating induced laser beam deflection, was employed to launch and detect surface acoustic waves (SAWs). The relation between the dispersive propagation velocity of SAWs to the coating-substrate geometry is exploited to determine the elastic properties of the NCD coating. The elastic properties are found to be consistent with literature values. The thermal properties of the coating were determined by monitoring the thermal diffusion induced washing away of the laser induced transient surface temperature grating. The transient thermal grating signals were fitted by the low-frequency limit of a thermoelastic model for a multilayer configuration. Similar to the dispersion of the surface acoustic wave velocity, the characteristic time of the thermal diffusion driven grating decay evolves from a coating-dominated value at short grating spacings towards a substrate-dominated value at grating spacings well exceeding the coating thickness. The grating spacing dependence of the corresponding effective thermal diffusivity was experimentally determined and fitted, leading to a value for the thermal diffusivity of the NCD coating α{sub NCD} = 8.4{sub −0.1}{sup +2.7} mm{sup 2}·s{sup −1}, which is an order of magnitude lower than that of the silicon substrate. The low value of the thermal diffusivity is interpreted with a simple touching model. - Highlights: • We investigate a thin nano-crystalline diamond coating. • We used two all optical surface acoustic wave based methods. • We found a young's modulus and density that is in line with literature. • The thermal diffusivity of the NCD coating was 2 orders of magnitude lower than the one of bulk diamond.

  1. Synthesis of thermally evaporated ZnSe thin film at room temperature

    Energy Technology Data Exchange (ETDEWEB)

    Khan, Taj Muhammad, E-mail: tajakashne@gmail.com [National Institute of Laser and Optronics (NILOP), P.O. Nilore-45650, Islamabad (Pakistan); Mehmood, Muhammad Farhan [Department of Applied Physics, Federal Urdu University of Arts, Science and Technology, Islamabad (Pakistan); Mahmood, Arshad; Shah, A.; Raza, Q.; Iqbal, Amjid; Aziz, U. [National Institute of Laser and Optronics (NILOP), P.O. Nilore-45650, Islamabad (Pakistan)

    2011-07-01

    Zinc selenide (ZnSe) thin film on glass substrates were prepared by thermal evaporation under high vacuum using the quasi-closed volume technique at room temperature (300 {+-} 2 K). The deposited ZnSe properties were assessed via X-ray diffraction, atomic force microscope (AFM), UV-Vis specrophotometry, Raman spectroscopy, photo-luminescence, Fourier transform infrared spectroscopy (FT-IR) and spectroscopic ellipsometry. The X-ray diffraction patterns of the film exhibited reflection corresponding to the cubic (111) phase (2{theta} = 27.20 deg.). This analysis indicated that the sample is polycrystalline and have cubic (Zinc blende) structure. The crystallites were preferentially oriented with the (111) planes parallel to the substrates. The AFM images showed that the ZnSe films have smooth morphology with roughness 6.74 nm. The transmittance spectrum revealed a high transmission of 89% in the infrared region ({>=} 600 nm) and a low transmission of 40% at 450 nm. The maximum transmission of 89.6% was observed at 640 nm. Optical band-gap was calculated from the transmission data of specrophotometry, photo-luminescence and ellipsometry and was 2.76, 2.74 and 2.82 eV respectively. Raman spectroscopic studies revealed two longitudinal optical phonon modes at 252 cm{sup -1} and 500 cm{sup -1}. In photoluminescence study, the luminescence peaks was observed at 452 nm corresponding to band to band emission. FT-IR study illustrated the existence of Zn-Se bonding in ZnSe thin film. The optical constants were calculated using spectroscopic ellipsometry and were determined from the best fit ellipsometric data in the wavelength regime of interest from 370-1000 nm. These results manifested excellent room temperature ZnSe synthesis and characteristics for opto-electronics technologies.

  2. Preparation and Investigation of the Thermal Stability of Phosphate-modified TiO2 Anatase Powders and Thin Films.

    Science.gov (United States)

    Prah, Uroš; Škofic, Irena Kozjek

    2017-12-01

    The temperature dependence of the anatase-to-rutile phase transition of TiO2 powders and thin films was studied. In order to shift the phase transition to higher temperature, samples were doped with a different amount of phosphate ions and their influence on the structure and thermal stability of the anatase phase was investigated. In addition, the effect of the catalyst form (powders or thin films) on the temperature of the anatase-to-rutile phase transition was observed. TiO2 thin films and powders were prepared using a simple sol-gel method with an alkoxide precursor and citric acid. The thin films were deposited on silicon and aluminum substrates using the dip-coating technique. The content of the anatase phase and the crystallite size at different annealing temperatures were monitored using X-ray diffraction. The course of the thermal decomposition was followed using thermal analyses. The morphology, particle size, shape and elemental makeup of the samples were investigated using scanning electron microscopy and energy-dispersive X-ray spectroscopy. The results showed that the phosphate ions successfully inhibited the growth of the anatase nanoparticles and delayed the phase transition to the rutile phase.

  3. Measurement of the Residual Stresses and Investigation of Their Effects on a Hardfaced Grid Plate due to Thermal Cycling in a Pool Type Sodium-Cooled Fast Reactor

    Directory of Open Access Journals (Sweden)

    S. Balaguru

    2016-01-01

    Full Text Available In sodium-cooled fast reactors (SFR, grid plate is a critical component which is made of 316 L(N SS. It is supported on core support structure. The grid plate supports the core subassemblies and maintains their verticality. Most of the components of SFR are made of 316 L(N/304 L(N SS and they are in contact with the liquid-metal sodium which acts as a coolant. The peak operating temperature in SFR is 550°C. However, the self-welding starts at 500°C. To avoid self-welding and galling, hardfacing of the grid plate has become necessary. Nickel based cobalt-free colmonoy 5 has been identified as the hardfacing material due to its lower dose rate by Plasma Transferred Arc Welding (PTAW. This paper is concerned with the measurement and investigations of the effects of the residual stress generated due to thermal cycling on a scale-down physical model of the grid plate. Finite element analysis of the hardfaced grid plate model is performed for obtaining residual stresses using elastoplastic analysis and hence the results are validated. The effects of the residual stresses due to thermal cycling on the hardfaced grid plate model are studied.

  4. Deuterium thermal desorption from Ni-rich deuterated Mg thin films

    Energy Technology Data Exchange (ETDEWEB)

    Patel, N.; Kale, A.; Mosaner, P.; Checchetto, R.; Miotello, A. [Dipartimento di Fisica dell' Universita di Trento, I-38050 Povo (Italy); Das, G. [Dipartimento di Medicina Sperimentale e Clinica, Universita degli Studi, Magna Grecia, I-88100 Catanzaro (Italy)

    2008-02-15

    Mg-Ni multilayers and Ni-rich Mg thin films were deposited by electron gun and pulsed laser deposition, respectively. Samples were submitted to thermal treatment in deuterium or hydrogen atmosphere at 423 K and {proportional_to}10{sup 5} Pa pressure to promote the metal to hydride phase transition. The H chemical bonding in the multilayer samples, after annealing in H{sub 2} atmosphere, was examined by Fourier transform infrared spectroscopy: the obtained spectra suggest that the samples with the Mg:Ni=2:1 atomic ratio contain the Mg{sub 2}NiH{sub 4} phase while the samples with lower Ni concentration contain both the MgH{sub 2} and the Mg{sub 2}NiH{sub 4} phases. The effect of the Ni additive on the stability of the deuteride phase was studied by thermal desorption spectroscopy (TDS). The TDS spectra of the single-phase Mg{sub 2}NiD{sub 4} samples show a TDS peak at 400 K. The TDS spectra of the two-phase samples show both the D{sub 2} desorption peak at 400 K and a second peak at higher temperature that we attributed to the dissociation of the MgD{sub 2} phase. The high-temperature peak shifts to lower temperatures by increasing the Ni content. It is suggested that in the two-phase samples, the lattice volumes having the Mg{sub 2}Ni structure resulting from the dissociation of the Mg{sub 2}NiD{sub 4} phase reduce the thermodynamic stability of the MgD{sub 2} phase. (author)

  5. Three dimensional evaluation of aluminum plates with wall-thinning by full-field pulse-echo laser ultrasound

    Science.gov (United States)

    Hong, Seung-Chan; Abetew, Ayalsew-Dagnew; Lee, Jung-Ryul; Ihn, Jeong-Beom

    2017-12-01

    We propose a full-field pulse-echo laser ultrasonic wave propagation imager (FF-PE-UPI) for the evaluation of structural defects. The FF-PE-UPI consists of a Q-switched laser for the generation of thermoelastic waves, a laser Doppler vibrometer (LDV) for sensing, and a two-axis translation stage for raster scanning of the combined generation and sensing laser beams. A-scan, B-scan, and C-scan data representations are used for the evaluation of structural defects. Three specimens were tested: a 4-mm aluminum plate with an area of 50% thickness reduction, a 6-mm aluminum plate with an area of 25% thickness reduction, and an 8-mm aluminum plate with engraved letters. The damages on the tested specimens were successfully visualized.

  6. A study of Gd-based parallel plate avalanche counter for thermal neutrons by MC simulation

    Energy Technology Data Exchange (ETDEWEB)

    Rhee, J.T.; Kim, H.G. [IAP, High Energy Physics Lab, Department of Physics, Konkuk University, Seoul 143-701 (Korea, Republic of); Ahmad, Farzana; Jeon, Y.J. [Liquid Crystal Research Center, Department of Chemistry, Konkuk University, Seoul 143-701 (Korea, Republic of); Jamil, M., E-mail: mjamil@konkuk.ac.kr [IAP, High Energy Physics Lab, Department of Physics, Konkuk University, Seoul 143-701 (Korea, Republic of); Division of International Studies, University College, Konkuk University, Seoul 143-701 (Korea, Republic of)

    2013-12-21

    In this work, we demonstrate the feasibility and characteristics of a single-gap parallel plate avalanche counter (PPAC) as a low energy neutron detector, based on Gd-converter coating. Upon falling on the Gd-converter surface, the incident low energy neutrons produce internal conversion electrons which are evaluated and detected. For estimating the performance of the Gd-based PPAC, a simulation study has been performed using GEANT4 Monte Carlo (MC) code. The detector response as a function of incident neutron energies in the range of 25–100 meV has been evaluated with two different physics lists. Using the QGSP{sub B}IC{sub H}P physics list and assuming 5μm converter thickness, 11.8%, 18.48%, and 30.28% detection efficiencies have been achieved for the forward-, the backward-, and the total response of the converter-based PPAC. On the other hand, considering the same converter thickness and detector configuration, with the QGSP{sub B}ERT{sub H}P physics list efficiencies of 12.19%, 18.62%, and 30.81%, respectively, were obtained. These simulation results are briefly discussed.

  7. Annual measured and simulated thermal performance analysis of a hybrid solar district heating plant with flat plate collectors and parabolic trough collectors in series

    DEFF Research Database (Denmark)

    Tian, Zhiyong; Perers, Bengt; Furbo, Simon

    2017-01-01

    the district heating network to about 70 °C and then the parabolic trough collectors would heat the preheated water to the required supply temperature of the district heating network. Annual measured and simulated thermal performances of both the parabolic trough collector field and the flat plate collector...... in large solar heating plants for a district heating network, a hybrid solar collector field with 5960 m2 flat plate collectors and 4039 m2 parabolic trough collectors in series was constructed in Taars, Denmark. The design principle is that the flat plate collectors preheat the return water from...... field are presented in this paper. The thermal performance of both collector fields with weather data of a Design Reference Year was simulated to have a whole understanding of the application of both collectors under Danish climate conditions as well. These results not only can provide a design basis...

  8. Ultra-wideband ladder filter using SH(0) plate wave in thin LiNbO(3) plate and its application to tunable filter.

    Science.gov (United States)

    Kadota, Michio; Tanaka, Shuji

    2015-05-01

    A cognitive radio terminal using vacant frequency bands of digital TV (DTV) channels, i.e., TV white space, strongly requires a compact tunable filter covering a wide frequency range of the DTV band (470 to 710 MHz in Japan). In this study, a T-type ladder filter using ultra-wideband shear horizontal mode plate wave resonators was fabricated, and a low peak insertion loss of 0.8 dB and an ultra-large 6 dB bandwidth of 240 MHz (41%) were measured in the DTV band. In addition, bandpass filters with different center frequencies of 502 and 653 MHz at 6 dB attenuation were numerically synthesized based on the same T-type ladder filter in conjunction with band rejection filters with different frequencies. The results suggest that the combination of the wideband T-type ladder filter and the band rejection filters connected with variable capacitors enables a tunable filter with large tunability of frequency and bandwidth as well as large rejection at the adjacent channels of an available TV white space.

  9. Origin of thermally stable ferroelectricity in a porous barium titanate thin film synthesized through block copolymer templating

    Directory of Open Access Journals (Sweden)

    Norihiro Suzuki

    2017-07-01

    Full Text Available A porous barium titanate (BaTiO3 thin film was chemically synthesized using a surfactant-assisted sol-gel method in which micelles of amphipathic diblock copolymers served as structure-directing agents. In the Raman spectrum of the porous BaTiO3 thin film, a peak corresponding to the ferroelectric tetragonal phase was observed at around 710 cm−1, and it remained stable at much higher temperature than the Curie temperature of bulk single-crystal BaTiO3 (∼130 °C. Measurements revealed that the ferroelectricity of the BaTiO3 thin film has high thermal stability. By analyzing high-resolution transmission electron microscope images of the BaTiO3 thin film by the fast Fourier transform mapping method, the spatial distribution of stress in the BaTiO3 framework was clearly visualized. Careful analysis also indicated that the porosity in the BaTiO3 thin film introduced anisotropic compressive stress, which deformed the crystals. The resulting elongated unit cell caused further displacement of the Ti4+ cation from the center of the lattice. This displacement increased the electric dipole moment of the BaTiO3 thin film, effectively enhancing its ferro(piezoelectricity.

  10. Origin of thermally stable ferroelectricity in a porous barium titanate thin film synthesized through block copolymer templating

    Science.gov (United States)

    Suzuki, Norihiro; Osada, Minoru; Billah, Motasim; Alothman, Zeid Abdullah; Bando, Yoshio; Yamauchi, Yusuke; Hossain, Md. Shahriar A.

    2017-07-01

    A porous barium titanate (BaTiO3) thin film was chemically synthesized using a surfactant-assisted sol-gel method in which micelles of amphipathic diblock copolymers served as structure-directing agents. In the Raman spectrum of the porous BaTiO3 thin film, a peak corresponding to the ferroelectric tetragonal phase was observed at around 710 cm-1, and it remained stable at much higher temperature than the Curie temperature of bulk single-crystal BaTiO3 (˜130 °C). Measurements revealed that the ferroelectricity of the BaTiO3 thin film has high thermal stability. By analyzing high-resolution transmission electron microscope images of the BaTiO3 thin film by the fast Fourier transform mapping method, the spatial distribution of stress in the BaTiO3 framework was clearly visualized. Careful analysis also indicated that the porosity in the BaTiO3 thin film introduced anisotropic compressive stress, which deformed the crystals. The resulting elongated unit cell caused further displacement of the Ti4+ cation from the center of the lattice. This displacement increased the electric dipole moment of the BaTiO3 thin film, effectively enhancing its ferro(piezo)electricity.

  11. Photo-induced and thermal reactions in thin films of an azobenzene derivative on Bi(111)

    Science.gov (United States)

    Bronner, Christopher; Tegeder, Petra

    2014-05-01

    Azobenzene is a prototypical molecular switch which can be interconverted with UV and visible light between a trans and a cis isomer in solution. While the ability to control their conformation with light is lost for many molecular photoswitches in the adsorbed state, there are some examples for successful photoisomerization in direct contact with a surface. However, there the process is often driven by a different mechanism than in solution. For instance, photoisomerization of a cyano-substituted azobenzene directly adsorbed on Bi(111) occurs via electronic excitations in the substrate and subsequent charge transfer. In the present study we observe two substrate-mediated trans-cis photoisomerization reactions of the same azobenzene derivative in two different environments within a multilayer thin film on Bi(111). Both processes are associated with photoisomerization and one is around two orders of magnitude more efficient than the other. Furthermore, the cis isomers perform a thermally induced reaction which may be ascribed to a back-isomerization in the electronic ground state or to a phenyl ring rotation of the cis isomer.

  12. Thermal stability of metal containing diamond-like carbon thin film fabricated by dual plasma deposition

    Science.gov (United States)

    Fu, Ricky K. Y.; Mei, Y. F.; Fu, M. Y.; Wei, C. B.; Siu, G. G.; Chu, Paul K.; Cheung, W. Y.; Wong, S. P.

    2004-12-01

    Diamond-like-carbon (DLC) films have an amorphous structure comprising a sophistical carbon matrix and have attracted a great deal of scientific interest. Metal-doped DLC (Me-DLC) can possess superior properties as metal nanoclusters or nanocrystalline metallic carbides can be embedded in the carbon network. Therefore, Me-DLC exhibits good adhesion to the substrate, high hardness, low friction coefficient and high magnitude of conductivity. In this work, a metal cathodic vacuum arc and acetylene dual plasma are synchronized to produce Me-DLC. We systematically fabricate the Me-DLC films by varying the acetylene flow rate and substrate bias voltage. Our results acquired by Rutherford backscattering spectrometry (RBS) show that the film thickness and metal content can be controlled by the process windows. Four point probe measurements illustrate a decrease in the resistivity with increasing metal content whereas x-ray photoelectron spectroscopy (XPS) and x-ray diffraction (XRD) results show the formation of carbide phases in the carbon matrix. To evaluate the thermal stability of the thin film, both undoped DLC and Me-DLC films are annealed at a series of temperature in argon ambient. Raman scattering results reveal that the Me-DLC films can tolerate a high annealing temperature without serious graphitization. It is believed that metals incorporation retards the restructuring of the carbon matrix during the annealing processes.

  13. Structural and optical properties of thermally evaporated Ga-In-Se thin films

    Science.gov (United States)

    Işik, Mehmet; Güllü, Hasan Hüseyin

    2014-05-01

    In this paper, structural and optical properties of Ga-In-Se (GIS) thin films deposited by thermal evaporation technique have been investigated. The effect of annealing was also studied for samples annealed at temperatures between 300°C and 500°C. X-ray diffraction, energy dispersive X-ray analysis and scanning electron microscopy have been used for structural characterization. It was reported that increase of annealing temperature results with better crystallization and chemical composition of the films were almost same. Optical properties of the films were studied by transmission measurements in the wavelength range of 320-1100 nm. The direct bandgap transitions with energies in the range of 1.52 eV and 1.65 eV were revealed for the investigated GIS films. Photon energy dependence of absorption coefficient showed that there exist three distinct transition regions for films annealed at 400°C and 500°C. The quasicubic model was applied for these transitions to calculate crystal-field splitting and spin-orbit splitting energy values.

  14. Thermal fluctuations in Y-Ba-Cu-O thin films near the transition temperature

    Energy Technology Data Exchange (ETDEWEB)

    Jiang, S.; Hallemeier, P.; Surya, C. (Northeastern Univ., Boston, MA (United States). Dept. of Electrical and Computer Engineering); Phillips, J.M. (AT and T Bell Labs., Murray Hill, NJ (United States))

    1994-11-01

    Detailed studies on the properties of low frequency noise in Y-Ba-Cu-O thin films in the transition region were conducted. The experimental results showed that the low frequency excess noise exhibited a lower cutoff frequency of about 5 Hz, below which the noise power spectra were independent of frequency. At T close to [Tc] and at small current biases the voltage noise power spectra were proportional to I[sup 2], ([partial derivative]R/[partial derivative]T)[sup 2] and inversely proportional to the volume of the device, [Omega]. In addition, low frequency noise measured from two segments separated by a distance of 300 [mu]m was found to be correlated. The lower cutoff frequencies computed for both the noise power spectra and the frequency dependent correlation function, according to the thermal fluctuation model, were found to be in good agreement with the experimental values. The experimental results provide strong evidence that the low frequency excess noise in the device originates from equilibrium temperature fluctuations for small I and T [approx equal] [Tc].

  15. Inexpensive Method of Testing Ambient and Thermally Elevated Resistive and Piezoresistive Thin-Film Pressure Gauges

    Science.gov (United States)

    Armstrong, Christopher; Rae, Philip; Heatwole, Eric; Tasker, Douglas; Los Alamos National Labortatory Team

    2017-06-01

    Manganin is an alloy that changes resistance when subjected to high-pressure, but is insensitive to temperature changes. Resistance curves as a function of pressure for these gauges have been established. Another commonly used piezoresistive pressure sensor are thin-film carbon gauges, which are more pressure sensitive than manganin gauges. Carbon gauge response in high temperature is not well quantified. The current research is focused on verifying these established resistance curves as well as verifying this specific experimental configuration. In this research the carbon gauges' resistance change is measured for thermally elevated gauges. In this setup a 20 mm caliber gun drove planar copper projectiles at the gauge, which was embedded in a copper anvil. The Hugoniot relationship allows for a comparison between observed and theoretical pressure over a pressure range 5 to 20 GPa for manganin gauges and 1 to 5 GPa for carbon gauges. The comparison between the data obtained in this research and that of others shows that the pressure-resistance curve of manganin does to not vary between lots of manganin. Additionally, the data shows that this setup is a relatively inexpensive quick means of testing gauge response to high-pressure shocks and is suitable for elevated temperature.

  16. High-throughput heterodyne thermoreflectance: Application to thermal conductivity measurements of a Fe-Si-Ge thin film alloy library

    Science.gov (United States)

    d'Acremont, Quentin; Pernot, Gilles; Rampnoux, Jean-Michel; Furlan, Andrej; Lacroix, David; Ludwig, Alfred; Dilhaire, Stefan

    2017-07-01

    A High-Throughput Time-Domain ThermoReflectance (HT-TDTR) technique was developed to perform fast thermal conductivity measurements with minimum user actions required. This new setup is based on a heterodyne picosecond thermoreflectance system. The use of two different laser oscillators has been proven to reduce the acquisition time by two orders of magnitude and avoid the experimental artefacts usually induced by moving the elements present in TDTR systems. An amplitude modulation associated to a lock-in detection scheme is included to maintain a high sensitivity to thermal properties. We demonstrate the capabilities of the HT-TDTR setup to perform high-throughput thermal analysis by mapping thermal conductivity and interface resistances of a ternary thin film silicide library FexSiyGe100-x-y (20 analysis areas of different ternary alloy compositions.

  17. Guided waves in pre-stressed hyperelastic plates and tubes: Application to the ultrasound elastography of thin-walled soft materials

    Science.gov (United States)

    Li, Guo-Yang; He, Qiong; Mangan, Robert; Xu, Guoqiang; Mo, Chi; Luo, Jianwen; Destrade, Michel; Cao, Yanping

    2017-05-01

    In vivo measurement of the mechanical properties of thin-walled soft tissues (e.g., mitral valve, artery and bladder) and in situ mechanical characterization of thin-walled artificial soft biomaterials in service are of great challenge and difficult to address via commonly used testing methods. Here we investigate the properties of guided waves generated by focused acoustic radiation force in immersed pre-stressed plates and tubes, and show that they can address this challenge. To this end, we carry out both (i) a theoretical analysis based on incremental wave motion in finite deformation theory and (ii) finite element simulations. Our analysis leads to a novel method based on the ultrasound elastography to image the elastic properties of pre-stressed thin-walled soft tissues and artificial soft materials in a non-destructive and non-invasive manner. To validate the theoretical and numerical solutions and demonstrate the usefulness of the corresponding method in practical measurements, we perform (iii) experiments on polyvinyl alcohol cryogel phantoms immersed in water, using the Verasonics V1 System equipped with a L10-5 transducer. Finally, potential clinical applications of the method have been discussed.

  18. Coupling of column liquid chromatography and surface-enhanced resonance Raman spectroscopy via a thin-layer chromatographic plate.

    NARCIS (Netherlands)

    Coulter, S.K.; Gooijer, C.; Velthorst, N.H.; Brinkman, U.A.T.; Somsen, G.W.

    1997-01-01

    Surface-enhanced resonance Raman (SERR) spectroscopy was used to characterize compounds separated by column liquid chromatography (LC). Three percent of the effluent from a conventional-size LC column were immobilized on a moving thinlayer chromatography (TLC) plate using a spray-jet

  19. Flat sources for active acoustic shielding based on distributed control of a vibrating plate coupled with a thin cavity

    NARCIS (Netherlands)

    Berkhoff, A.P.; Ho, J.H.

    2013-01-01

    Air cavities between plates are often used to improve noise insulation by passive means, especially at high frequencies. Such configurations may suffer from resonances, such as due to the mass-air-mass resonance. Lightweight structures, which tend to be undamped, may suffer from structural

  20. Layer-by-layer thin film of reduced graphene oxide and gold nanoparticles as an effective sample plate in laser-induced desorption/ionization mass spectrometry.

    Science.gov (United States)

    Kuo, Tsung-Rong; Wang, Di-Yan; Chiu, Yu-Chen; Yeh, Yun-Chieh; Chen, Wei-Ting; Chen, Ching-Hui; Chen, Chun-Wei; Chang, Huan-Cheng; Hu, Cho-Chun; Chen, Chia-Chun

    2014-01-27

    This work demonstrated a simple platform for rapid and effective surface-assisted laser desorption/ionization time-of-flight mass spectrometry (SALDI-TOF MS) measurements based on the layer structure of reduced graphene oxide (rGO) and gold nanoparticles. A multi-layer thin film was fabricated by alternate layer-by-layer depositions of rGO and gold nanoparticles (LBL rGO/AuNP). The flat and clean two-dimensional film was served as the sample plate and also functioned as the matrix in SALDI-TOF MS. By simply one-step deposition of analytes onto the LBL rGO/AuNP sample plate, the MS measurements of various homogeneous samples were ready to execute. The optimization of MS signal was reached by the variation of the layer numbers of rGO and gold nanoparticles. Also, the small molecules including amino acids, carbohydrates and peptides were successfully analyzed in SALDI-TOF MS using the LBL rGO/AuNP sample plate. The results showed that the signal intensity, S N(-1) ratio and reproducibility of SALDI-TOF spectra have been significantly improved in comparison to the uses of gold nanoparticles or α-cyano-4-hydroxy-cinnamic acid (CHCA) as the assisted matrixes. Taking the advantages of the unique properties of rGO and gold nanoparticles, the ready-to-use MS sample plate, which could absorb and dissipate laser energy to analytes quite efficiently and homogeneously, has shown great commercial potentials for MS applications. Copyright © 2013 Elsevier B.V. All rights reserved.

  1. Direct synthesis and characterization of optically transparent conformal zinc oxide nanocrystalline thin films by rapid thermal plasma CVD

    OpenAIRE

    Pedersen, Joachim D; Esposito, Heather J; Teh, Kwok Siong

    2011-01-01

    We report a rapid, self-catalyzed, solid precursor-based thermal plasma chemical vapor deposition process for depositing a conformal, nonporous, and optically transparent nanocrystalline ZnO thin film at 130 Torr (0.17 atm). Pure solid zinc is inductively heated and melted, followed by ionization by thermal induction argon/oxygen plasma to produce conformal, nonporous nanocrystalline ZnO films at a growth rate of up to 50 nm/min on amorphous and crystalline substrates including Si (100), fuse...

  2. Thermal Characteristics of Amorphous Indium-Gallium-Zinc-Oxide and Graphite in Display Panel Based Thin Film Transistors.

    Science.gov (United States)

    Kim, Hak-Jun; Kim, Youn-Jea

    2015-11-01

    One of the important design factors in the smart electronic industry is proper heat treatment of the display panel. In order to improve the heat transfer performance of display panels, we analyzed a three-dimensional model of multi-stack layers of the thin film transistors (TFTs). In particular, we numerically investigated the thermal barrier effects of active layers having different material properties of a-IGZO (isotropy) and graphite (anisotropy). We calculated the temperature distribution on the display panel with each active layer, using the commercial code, COMSOL Multiphysics. We graphically depict comparative results of the thermal characteristics between a-IGZO and graphite with the stacked structure of the TFTs.

  3. Preparation of SnS thin films with gear-like sheet appearance by close-spaced vacuum thermal evaporation

    Science.gov (United States)

    Shao, Zhangpeng; Shi, Chengwu; Chen, Junjun; Zhang, Yanru

    2017-07-01

    SnS thin films with gear-like sheet appearance were successfully prepared by close-spaced vacuum thermal evaporation using SnS powders as a source. The influence of substrate temperature on the surface morphology, chemical composition, crystal structure and optical property of SnS thin films was investigated by scanning electron microscopy, energy-dispersive spectroscopy, X-ray diffraction and ultraviolet-visible-near infrared spectroscopy. The results revealed that serration architecture appeared obviously in the edge of the SnS sheet and the strongest peak at 2𝜃=31.63∘ was broadened and many shoulder peaks were observed with increasing substrate temperature. The atomic ratio of Sn to S increased from 1:1.08 to 1:1.20, the grain size became slightly smaller and the optical absorption edge had a blueshift in the SnS thin film with decreasing substrate temperature.

  4. Design and fabrication of thin film Bi-Sb and Bi-Cu thermopiles for IR thermal radiation detection

    CERN Document Server

    Afzalzadeh, R

    2003-01-01

    Thin film thermopiles are widely used as small size sensors, in particular to sense infra-red thermal radiations. In this paper a method for designing and fabrication of thin films Bi-Cu thermopiles in linear in linear array of 8 and 11 elements in series and mono-layer is introduced. Also, fabrication of of Bi-Cu thin film thermopiles, which are used as IR radiation sensors, made in multilayer from with 100 series junctions in circular shape are presented. The samples are fabricated on a PCB board with double-side copper laminated as a substrate. The results of our measurements show that the output voltage produced due to temperature difference between junctions, is very sensitive and linear to temperature difference.

  5. Application of Ultra Thin Titanium-based Thermal Ground Plane (TiTGP) Thermal Solution for DoD Applications

    Science.gov (United States)

    2017-03-01

    thinner TGP, thin- wall cylindrical heat pipes were flattened, and bonded between two aluminum facesheets. Although these TGPs were thinner (~4 mm...tolerant to internal temporal working fluid pressure variations caused by temperature. The thin- wall flattened heat pipes tended toward their...2.6 ppm/°C, respectively) resulting in delamination of components and cracking The Titanium Based Approach Titanium has superior mechanical

  6. Robust moisture and thermally stable phosphor glass plate for highly unstable sulfide phosphors in high-power white light-emitting diodes.

    Science.gov (United States)

    Lee, Jin Seok; Unithrattil, Sanjith; Kim, Sunghoon; Lee, In Jae; Lee, Hyungeui; Im, Won Bin

    2013-09-01

    Potential white light-emitting diode (LED) phosphor SrGa2S4, which remains superfluous due to its unstable nature in the presence of moisture, was successfully integrated in a high-power white LED system by developing a glass-based phosphor plate. A glass system with softening temperature at around 600°C, which lies far below the possible decomposition temperature of the sulfide phosphor, provides a stable shield. Physical properties such as thermal stability, transparency, and lower porosity along with chemical stability under operating conditions of the LEDs ensure long-term operability. H2S emission due to the decomposition of sulfide phosphors, which leads to corrosion of LED electrodes, was contained using the developed plate. Higher thermal resistivity of the developed glass system in comparison with conventional resins ensures lower thermal quenching of the luminescence and better color purity.

  7. Effects of Thermal Annealing on the Optical Properties of Titanium Oxide Thin Films Prepared by Chemical Bath Deposition Technique

    OpenAIRE

    H.U. Igwe; O.E. Ekpe; E.I. Ugwu

    2010-01-01

    A titanium oxide thin film was prepared by chemical bath deposition technique, deposited on glass substrates using TiO2 and NaOH solution with triethanolamine (TEA) as the complexing agent. The films w ere subjected to post deposition annealing under various temperatures, 100, 150, 200, 300 and 399ºC. The thermal treatment streamlined the properties of the oxide films. The films are transparent in the entire regions of the electromagnetic spectrum, firmly adhered to the substrate and resistan...

  8. Experimental and Numerical Analyses of a Flat Plate Photovoltaic/Thermal Solar Collector

    Directory of Open Access Journals (Sweden)

    Francesco Calise

    2017-04-01

    Full Text Available This paper presents a one-dimensional finite-volume model of an unglazed photovoltaic/thermal (PVT solar collector. The unit consists of a conventional solar photovoltaic (PV collector coupled with a suitable heat exchanger. In particular, the collector includes a roll bond heat exchanger and it is not equipped with back and frame insulation. The system is discretized along the flow direction (longitudinal of the cogenerative collector. For each finite-volume element of the discretized computational domain, mass and energy balances are implemented. The collector geometry and materials parameters are taken from a commercially available device. An on-field experimental investigation is performed in order to validate the proposed model. The model is used to evaluate both electrical and thermodynamic parameters for each element of the domain and for fixed operating conditions. Finally, a sensitivity analysis is also performed in order to investigate the energetic performance of the cogenerative collector as a function of the main design/environmental parameters.

  9. Electromagnetic Acoustic Transducers Applied to High Temperature Plates for Potential Use in the Solar Thermal Industry

    Directory of Open Access Journals (Sweden)

    Maria Kogia

    2015-12-01

    Full Text Available Concentrated Solar Plants (CSPs are used in solar thermal industry for collecting and converting sunlight into electricity. Parabolic trough CSPs are the most widely used type of CSP and an absorber tube is an essential part of them. The hostile operating environment of the absorber tubes, such as high temperatures (400–550 °C, contraction/expansion, and vibrations, may lead them to suffer from creep, thermo-mechanical fatigue, and hot corrosion. Hence, their condition monitoring is of crucial importance and a very challenging task as well. Electromagnetic Acoustic Transducers (EMATs are a promising, non-contact technology of transducers that has the potential to be used for the inspection of large structures at high temperatures by exciting Guided Waves. In this paper, a study regarding the potential use of EMATs in this application and their performance at high temperature is presented. A Periodic Permanent Magnet (PPM EMAT with a racetrack coil, designed to excite Shear Horizontal waves (SH0, has been theoretically and experimentally evaluated at both room and high temperatures.

  10. In-Situ Testing of the Thermal Diffusivity of Polysilicon Thin Films

    National Research Council Canada - National Science Library

    Gu, Yi-Fan; Zhou, Zai-Fa; Sun, Chao; Li, Wei-Hua; Huang, Qing-An

    2016-01-01

    ...(t) varies as temperature rises. A delicate thermodynamic model considering thermal convection, thermal radiation, and film-to-substrate heat conduction was established for the testing structure...

  11. Annealing study and thermal investigation on bismuth sulfide thin films prepared by chemical bath deposition in basic medium

    Science.gov (United States)

    Dachraoui, O.; Merino, J. M.; Mami, A.; León, M.; Caballero, R.; Maghraoui-Meherzi, H.

    2018-02-01

    Bismuth sulfide thin films were prepared by chemical bath deposition using thiourea as sulfide ion source in basic medium. First, the effects of both the deposition parameters on film growth as well as the annealing effect under argon and sulfur atmosphere on as-deposited thin films were studied. The parameters were found to be influential using the Doehlert matrix experimental design methodology. Ranges for a maximum surface mass of films (3 mg cm-2) were determined. A well-crystallized major phase of bismuth sulfide with stoichiometric composition was achieved at 190 °C for 3 h. The prepared thin films were characterized using grazing incidence X-ray diffraction, scanning electron microscopy and energy-dispersive X-ray analysis. Second, the bandgap energy value was found to be 1.5 eV. Finally, the thermal properties have been studied for the first time by means of the electropyroelectric (EPE) technique. Indeed, the thermal conductivity varied in the range of 1.20-0.60 W m-1 K-1, while the thermal diffusivity values increased in terms of the annealing effect ranging from 1.8 to 3.5 10-7 m2 s-1.

  12. Electro-Plating and Characterisation of CdTe Thin Films Using CdCl2 as the Cadmium Source

    Directory of Open Access Journals (Sweden)

    Nor A. Abdul-Manaf

    2015-09-01

    Full Text Available Cadmium telluride (CdTe thin films have been successfully prepared from an aqueous electrolyte bath containing cadmium chloride (CdCl2·H2O and tellurium dioxide (TeO2 using an electrodeposition technique. The structural, electrical, morphological and optical properties of these thin films have been characterised using X-ray diffraction (XRD, Raman spectroscopy, optical profilometry, DC current-voltage (I-V measurements, photoelectrochemical (PEC cell measurement, scanning electron microscopy (SEM, atomic force microscopy (AFM and UV-Vis spectrophotometry. It is observed that the best cathodic potential is 698 mV with respect to standard calomel electrode (SCE in a three electrode system. Structural analysis using XRD shows polycrystalline crystal structure in the as-deposited CdTe thin films and the peaks intensity increase after CdCl2 treatment. PEC cell measurements show the possibility of growing p-, i- and n-type CdTe layers by varying the growth potential during electrodeposition. The electrical resistivity of the as-deposited layers are in the order of 104 Ω·cm. SEM and AFM show that the CdCl2 treated samples are more roughness and have larger grain size when compared to CdTe grown by CdSO4 precursor. Results obtained from the optical absorption reveal that the bandgap of as-deposited CdTe (1.48–1.52 eV reduce to (1.45–1.49 eV after CdCl2 treatment. Full characterisation of this material is providing new information on crucial CdCl2 treatment of CdTe thin films due to its built-in CdCl2 treatment during the material growth. The work is progressing to fabricate solar cells with this material and compare with CdTe thin films grown by conventional sulphate precursors.

  13. Skeletal Structure in Postmenopausal Women with Osteopenia and Fractures is Characterized by Abnormal Trabecular Plates and Cortical Thinning

    Science.gov (United States)

    Stein, Emily M.; Kepley, Anna; Walker, Marcella; Nickolas, Thomas L.; Nishiyama, Kyle; Zhou, Bin; Liu, X. Sherry; McMahon, Donald J.; Zhang, Chiyuan; Boutroy, Stephanie; Cosman, Felicia; Nieves, Jeri; Guo, X. Edward; Shane, Elizabeth

    2014-01-01

    The majority of fragility fractures occur in women with osteopenia rather than osteoporosis by dual energy x-ray absorptiometry (DXA). However, it is difficult to identify which women with osteopenia are at greatest risk. We performed this study to determine whether osteopenic women with and without fracture had differences in trabecular morphology and biomechanical properties of bone. We hypothesized that women with fractures would have fewer trabecular plates, less trabecular connectivity and lower stiffness. We enrolled 117 postmenopausal women with osteopenia by DXA (mean age 66 years; 58 with fragility fractures and 59 non-fractured controls). All had areal bone mineral density by DXA. Trabecular and cortical volumetric BMD (vBMD), trabecular microarchitecture, and cortical porosity were measured by high resolution peripheral computed tomography (HR-pQCT) of the distal radius and tibia. HR-pQCT scans were subjected to finite element analysis to estimate whole bone stiffness and individual trabecula segmentation (ITS) to evaluate trabecular type (as plate or rod), orientation and connectivity. Groups had similar age, race, BMI, and mean T-scores. Fracture subjects had lower cortical and trabecular vBMD, thinner cortices, and thinner more widely separated trabeculae. By ITS, fracture subjects had fewer trabecular plates, less axially aligned trabeculae and less trabecular connectivity. Whole bone stiffness was lower in women with fractures. Cortical porosity did not differ. Differences in cortical bone were found at both sites, whereas trabecular differences were more pronounced at the radius. In summary, postmenopausal women with osteopenia and fractures had lower cortical and trabecular vBMD, thinner, more widely separated and rod-like trabecular structure, less trabecular connectivity and lower whole bone stiffness compared to controls, despite similar aBMD by DXA. Our results suggest that in addition to trabecular and cortical bone loss, changes in plate and

  14. Forced convection heat transfer of power law non-Newtonian fluids between two semi-infinite plates with variable thermal conductivity

    Science.gov (United States)

    Li, Botong; Zhang, Wei; Zhu, Liangliang

    2016-09-01

    This paper presents an investigation of forced convection heat transfer in power-law non-Newtonian fluids between two semi-infinite plates with variable thermal conductivity. Three cases of different thermal conductivity models are considered: (i) thermal conductivity is a constant, (ii) thermal conductivity is a linear function of temperature, (iii) thermal conductivity is a power-law function of temperature gradient (Zheng's model). Governing equations are solved using the finite element method with the ‘ghost’ time introduced to the control equations, which does not affect the results because the velocity and temperature will remain unchanged when the steady state is reached. Results for the solutions of different variable models are presented as well as the analysis of the associated heat transfer characteristics. It is shown that the heat transfer behaviours are strongly dependent on the power-law index (n) in all models. For example, when n 1.

  15. Vibration and Buckling of Web Plate of the Plate Girder

    OpenAIRE

    高橋, 和雄; 呉, 明強; 中澤, 聡志; 筑紫, 宏之

    1998-01-01

    The vibration and buckling of the web of the plate girder are studied in this paper. The small deflection theory of the thin plate is used. The finite strip method is employed to solve vibration and buckling of the plate girder. Natural frequenies of buckling properties are shown for various plate girder bridges.

  16. Effect of openings collectors and solar irradiance on the thermal efficiency of flat plate-finned collector for indirect-type passive solar dryer

    Science.gov (United States)

    Batubara, Fatimah; Dina, Sari Farah; Klaudia Kathryn Y., M.; Turmuzi, M.; Siregar, Fitri; Panjaitan, Nora

    2017-06-01

    Research on the effect of openings solar collector and solar irradiance to thermal efficiency has been done. Solar collector by flat plate-finned type consists of 3 ply insulator namely wood, Styrofoam and Rockwool with thickness respectively are 10 mm, 25 mm and 50 mm. Absorber plate made of aluminum sheet with thickness of 0.30 mm, painted by black-doff. Installation of 19 units fins (length x height x thickness: 1000x20x10 mm) on the collector will increase surface area of absorber so it can receive much more solar energy. The solar collector cover is made of glass (thickness of 5 mm). During the research, the solar irradiance and temperature of collector are measured and recorded every five minutes. Temperature measurement performed on the surface of the absorber plate, inside of collector, surface cover and the outer side insulator (plywood). This data is used to calculate the heat loss due to conduction, convection and radiation on the collector. Openings of collectors vary as follows: 100%, 75%, 15% and 0% (total enclosed). The data collecting was conducted from 09.00 am to 17.00 pm and triplicates. The collector thermal efficiency calculated based on the ratio of the amount of heat received to the solar irradiance absorbed. The results show that each of openings solar collector has different solar irradiance (because it was done on a different day) which is in units of W/m2: 390 (100% open), 376 (75% open), 429 (15% open), and 359 (totally enclosed). The highest thermal efficiency is in openings variation of 15% opened. These results indicate that the efficiency of the collector is influenced by the solar irradiance received by the collector and the temperature on the collector plate. The highest thermal efficiency is in variation of openings 15%. These indicate that the efficiency of the collector was influenced by solar irradiance received by the collector and openings of the collector plate.

  17. The evolution and analysis of electrical percolation threshold in nanometer scale thin films deposited by electroless plating

    Energy Technology Data Exchange (ETDEWEB)

    Sabayev, V., E-mail: vadimsab@eng.tau.ac.il [Department of Physical Electronics, Faculty of Engineering, Tel Aviv University Ramat Aviv, Tel Aviv 69978 (Israel); Croitoru, N.; Inberg, A.; Shacham-Diamand, Y. [Department of Physical Electronics, Faculty of Engineering, Tel Aviv University Ramat Aviv, Tel Aviv 69978 (Israel)

    2011-05-16

    Research highlights: {yields} The evolution of percolation threshold in electroless deposited Ag and Cu thin films was studied and ELD as a method for controllable percolation was analyzed. {yields} It was observed that Ag and Cu thin films reach percolation threshold at the thicknesses of 35 nm and 30 nm, respectively. {yields} It has been shown that the film resistivity varies according to power law. The critical exponents of 0.95 and 1.04 for Ag and Cu, respectively, were extracted. - Abstract: Extension of Ultra Large Scale Integration (ULSI) to a nanometer scale elevates the importance of interconnect resistivity in addition to conventional problems of coverage and electromigration. In this work we study electrical properties of ultra thin silver (Ag) and copper (Cu) films prepared by electroless deposition (ELD) in order to provide low resistivity, stable interconnect metallization technology and electrical contacts. The thin film is modeled by assuming metal conducting clusters separated by empty dielectric gaps. The continuity of the film or gap size is controlled by film thickness with respect to the growth mode of each metal. Analysis of the electrical properties of thin films at percolation threshold demonstrates that insulator-conductor transition occurs at the thickness about 35 nm and 30 nm for Ag and Cu films, respectively. At these thicknesses film roughness is constant, therefore, scattering on film walls remains unaffected and resistivity change can be associated with a percolation mechanism. The resistivity as a function of thickness varies according to power law and reaches saturation value of 2.5 {mu}{Omega} cm and 4.3 {mu}{Omega} cm at the thicknesses of 60 nm and 50 nm with critical exponents ({tau}) of 0.95 and 1.04 for Ag and Cu thin films, respectively. The X-ray Photoelectron Spectroscopy analysis has not detected contaminations or oxidation states. The strong dependence of the film surface roughness on metal ion concentration in solution

  18. Dimension- and shape-dependent thermal transport in nano-patterned thin films investigated by scanning thermal microscopy

    Science.gov (United States)

    Ge, Yunfei; Zhang, Yuan; Weaver, Jonathan M. R.; Dobson, Phillip S.

    2017-12-01

    Scanning thermal microscopy (SThM) is a technique which is often used for the measurement of the thermal conductivity of materials at the nanometre scale. The impact of nano-scale feature size and shape on apparent thermal conductivity, as measured using SThM, has been investigated. To achieve this, our recently developed topography-free samples with 200 and 400 nm wide gold wires (50 nm thick) of length of 400–2500 nm were fabricated and their thermal resistance measured and analysed. This data was used in the development and validation of a rigorous but simple heat transfer model that describes a nanoscopic contact to an object with finite shape and size. This model, in combination with a recently proposed thermal resistance network, was then used to calculate the SThM probe signal obtained by measuring these features. These calculated values closely matched the experimental results obtained from the topography-free sample. By using the model to analyse the dimensional dependence of thermal resistance, we demonstrate that feature size and shape has a significant impact on measured thermal properties that can result in a misinterpretation of material thermal conductivity. In the case of a gold nanowire embedded within a silicon nitride matrix it is found that the apparent thermal conductivity of the wire appears to be depressed by a factor of twenty from the true value. These results clearly demonstrate the importance of knowing both probe-sample thermal interactions and feature dimensions as well as shape when using SThM to quantify material thermal properties. Finally, the new model is used to identify the heat flux sensitivity, as well as the effective contact size of the conventional SThM system used in this study.

  19. Thermal stability of a highly-deformed warm-rolled tungsten plate in the temperature range 1100 °C to 1250 °C

    DEFF Research Database (Denmark)

    Alfonso Lopez, Angel; Juul Jensen, Dorte; Luo, G.-N.

    2015-01-01

    Pure tungsten is considered as armor material for the most critical parts of fusion reactors (i.e. the divertor and the first wall), among other reasons due to its high melting point (3422 °C) and recrystallization temperature. The thermal stability of a pure tungsten plate warm-rolled to a high...... be rationalized in terms of a logarithmic recovery kinetics and a Johnson-Mehl-Avrami-Kolmogorov recrystallization kinetics accounting for an incubation time of recrystallization. The observed time spans for recrystallization and the corresponding recrystallization activation energy for this highly deformed plate...

  20. Thermally evaporated mechanically hard tin oxide thin films for opto-electronic apllications

    Energy Technology Data Exchange (ETDEWEB)

    Tripathy, Sumanta K.; Rajeswari, V. P. [Centre for Nano Science and Technology, GVP College of Engineering (Autonomous), Visakhapatnam- 530048 (India)

    2014-01-28

    Tungsten doped tin oxide (WTO) and Molybdenum doped tin oxide (MoTO) thin film were deposited on corn glass by thermal evaporation method. The films were annealed at 350°C for one hour. Structural analysis using Xray diffraction data shows both the films are polycrystalline in nature with monoclinic structure of tin oxide, Sn{sub 3}O{sub 4}, corresponding to JCPDS card number 01-078-6064. SEM photograph showed that both the films have spherical grains with size in the range of 20–30 nm. Compositional analysis was carried out using EDS which reveals the presence of Sn, O and the dopant Mo/W only thereby indicating the absence of any secondary phase in the films. The films are found to contain nearly 6 wt% of Mo, 8 wt% of W as dopants respectively. The transmission pattern for both the films in the spectral range 200 – 2000 nm shows that W doping gives a transparency of nearly 80% from 380 nm onwards while Mo doping has less transparency of 39% at 380nm. Film hardness measurement using Triboscope shows a film hardness of about 9–10 GPa for both the films. It indicates that W or M doping in tin oxide provides the films the added advantage of withstanding the mechanical wear and tear due to environmental fluctuations By optimizing the optical and electrical properties, W/Mo doped tin oxide films may be explored as window layers in opto-electronic applications such as solar cells.

  1. Enhanced stress corrosion cracking resistance and electrical conductivity of a T761 treated Al-Zn-Mg-Cu alloy thin plate

    Science.gov (United States)

    Chen, Xu; Zhai, Sudan; Gao, Di; Liu, Ye; Xu, Jing; Liu, Yang

    2018-01-01

    The stress corrosion cracking (SCC) behavior, electrical conductivity and mechanical properties of an Al-Zn-Mg-Cu alloy pre-stretched thin plate for wing skin were researched in this paper. The microstructures and SCC fracture surfaces of the alloy treated at different conditions were characterized by transmission electron microscopy, optical microscopy and scanning electron microscopy. Results indicated that with the increasing of aging temperature, the electrical conductivity and the elongation increased greatly, while the strength decreased gradually which were closely associated with the type and morphology of the precipitates. Compared with the T6 treated alloy, the SCC resistance of the T761 treated Al-Zn-Mg-Cu alloy was improved greatly. The SCC behavior of the T6 treated alloy was dominated by anodic dissolution theory, whereas the hydrogen induced cracking controlled the fracture behavior of the T761 treated alloy which was influenced by the morphology of grain boundary precipitates in this investigated alloy.

  2. Thermal and Stress Characterization of Various Thin-Disk Laser Configurations at Room Temperature

    Science.gov (United States)

    2011-01-31

    alternative is the use of ceramic materials. Highly translucent and low scattering ceramic materials have been produced using purely chemical reactions and...Operational performance of kilowatt-class thin-disk ceramic and single crystal Yb:YAG lasers is presented. High pump power is applied to various thin...5670 MC RN-M1, Kirtland Air Force Base, NM USA 87117 ABSTRACT Operational performance of kilowatt-class thin-disk ceramic and single crystal

  3. The thermal properties of amorphous Fe40Pd40B20 and Fe60Pd20B20 thin films

    Science.gov (United States)

    Chen, Yuan-Tsung

    2015-07-01

    The thermal stability of FePdB thin films was studied using nonisothermal and isothermal analyses. X-ray diffraction (XRD) patterns indicated that Fe40Pd40B20 and Fe60Pd20B20 films with thicknesses in the range 25-75 Å were amorphous, whereas Fe40Pd40B20 and Fe60Pd20B20 films with thicknesses in the range 100-200 Å exhibited a nanocrystalline FePd (111) structure. The crucial glass forming ability index (γ and γm) was determined using the differential scanning calorimetry (DSC) results of amorphous FePdB films. The Kissinger formula was applied to calculate the activation energy (Q) of crystallization for determining the resistance of the films to crystallization. Thermal analysis showed that the thermal stability and incubation time of Fe40Pd40B20 are more favorable than those of Fe60Pd20B20.

  4. South China Sea crustal thickness and lithosphere thinning from satellite gravity inversion incorporating a lithospheric thermal gravity anomaly correction

    Science.gov (United States)

    Kusznir, Nick; Gozzard, Simon; Alvey, Andy

    2016-04-01

    The distribution of ocean crust and lithosphere within the South China Sea (SCS) are controversial. Sea-floor spreading re-orientation and ridge jumps during the Oligocene-Miocene formation of the South China Sea led to the present complex distribution of oceanic crust, thinned continental crust, micro-continents and volcanic ridges. We determine Moho depth, crustal thickness and continental lithosphere thinning (1- 1/beta) for the South China Sea using a gravity inversion method which incorporates a lithosphere thermal gravity anomaly correction (Chappell & Kusznir, 2008). The gravity inversion method provides a prediction of ocean-continent transition structure and continent-ocean boundary location which is independent of ocean isochron information. A correction is required for the lithosphere thermal gravity anomaly in order to determine Moho depth accurately from gravity inversion; the elevated lithosphere geotherm of the young oceanic and rifted continental margin lithosphere of the South China Sea produces a large lithosphere thermal gravity anomaly which in places exceeds -150 mGal. The gravity anomaly inversion is carried out in the 3D spectral domain (using Parker 1972) to determine 3D Moho geometry and invokes Smith's uniqueness theorem. The gravity anomaly contribution from sediments assumes a compaction controlled sediment density increase with depth. The gravity inversion includes a parameterization of the decompression melting model of White & McKenzie (1999) to predict volcanic addition generated during continental breakup lithosphere thinning and seafloor spreading. Public domain free air gravity anomaly, bathymetry and sediment thickness data are used in this gravity inversion. Using crustal thickness and continental lithosphere thinning factor maps with superimposed shaded-relief free-air gravity anomaly, we improve the determination of pre-breakup rifted margin conjugacy, rift orientation and sea-floor spreading trajectory. SCS conjugate margins

  5. Direct analysis of pharmaceutical formulations from non-bonded reversed-phase thin-layer chromatography plates by desorption electrospray ionisation ion mobility mass spectrometry.

    Science.gov (United States)

    Harry, Emma L; Reynolds, James C; Bristow, Anthony W T; Wilson, Ian D; Creaser, Colin S

    2009-09-01

    The direct analysis of pharmaceutical formulations and active ingredients from non-bonded reversed-phase thin layer chromatography (RP-TLC) plates by desorption electrospray ionisation (DESI) combined with ion mobility mass spectrometry (IM-MS) is reported. The analysis of formulations containing analgesic (paracetamol), decongestant (ephedrine), opiate (codeine) and stimulant (caffeine) active pharmaceutical ingredients is described, with and without chromatographic development to separate the active ingredients from the excipient formulation. Selectivity was enhanced by combining ion mobility and mass spectrometry to characterise the desorbed gas-phase analyte ions on the basis of mass-to-charge ratio (m/z) and gas-phase ion mobility (drift time). The solvent composition of the DESI spray using a step gradient was varied to optimise the desorption of active pharmaceutical ingredients from the RP-TLC plates. The combined RP-TLC/DESI-IM-MS approach has potential as a rapid and selective technique for pharmaceutical analysis by orthogonal gas-phase electrophoretic and mass-to-charge separation. Copyright (c) 2009 John Wiley & Sons, Ltd.

  6. Temperature of Heating and Cooling of Massive, Thin, and Wedge-Shaped Plates from Hard-to-Machine Steels During Their Grinding

    Science.gov (United States)

    Dement‧ev, V. B.; Ivanova, T. N.; Dolginov, A. M.

    2017-01-01

    Grinding of flat parts occurs by solid abrasive particles due to the physicomechanical process of deformation and to the action of a process liquid at high temperatures in a zone small in volume and difficult for observation. The rate of heating and cooling depends on the change in the intensity of the heat flux and in the velocity and time of action of the heat source. A study has been made of the regularities of the influence of each of these parameters on the depth and character of structural transformations during the grinding of flat parts from hard-to-machine steels. A procedure to calculate temperature in grinding massive, thin, and wedge-shaped parts has been developed with account taken of the geometric and thermophysical parameters of the tool and the treated part, and also of cutting regimes. The procedure can be used as a constituent part in developing a system for automatic design of the technological process of grinding of flat surfaces. A relationship between the temperature in the grinding zone and the regimes of treatment has been established which makes it possible to control the quality of the surface layer of massive, thin, and wedge-shaped plates from hard-to-machine steels. The rational boundaries of shift of cutting regimes have been determined.

  7. Acoustic emission source localization in thin metallic plates: A single-sensor approach based on multimodal edge reflections.

    Science.gov (United States)

    Ebrahimkhanlou, A; Salamone, S

    2017-07-01

    This paper presents a new acoustic emission (AE) source localization for isotropic plates with reflecting boundaries. This approach that has no blind spot leverages multimodal edge reflections to identify AE sources with only a single sensor. The implementation of the proposed approach involves three main steps. First, the continuous wavelet transform (CWT) and the dispersion curves of the fundamental Lamb wave modes are utilized to estimate the distance between an AE source and a sensor. This step uses a modal acoustic emission approach. Then, an analytical model is proposed that uses the estimated distances to simulate the edge-reflected waves. Finally, the correlation between the experimental and the simulated waveforms is used to estimate the location of AE sources. Hsu-Nielsen pencil lead break (PLB) tests were performed on an aluminum plate to validate this algorithm and promising results were achieved. Based on these results, the paper reports the statistics of the localization errors. Copyright © 2017 Elsevier B.V. All rights reserved.

  8. Control of Nanoplane Orientation in voBN for High Thermal Anisotropy in a Dielectric Thin Film: A New Solution for Thermal Hotspot Mitigation in Electronics.

    Science.gov (United States)

    Cometto, Olivier; Samani, Majid K; Liu, Bo; Sun, Shuangxi; Tsang, Siu Hon; Liu, Johan; Zhou, Kun; Teo, Edwin H T

    2017-03-01

    High anisotropic thermal materials, which allow heat to dissipate in a preferential direction, are of interest as a prospective material for electronics as an effective thermal management solution for hot spots. However, due to their preferential heat propagation in the in-plane direction, the heat spreads laterally instead of vertically. This limitation makes these materials ineffective as the density of hot spots increases. Here, we produce a new dielectric thin film material at room temperature, named vertically ordered nanocrystalline h-BN (voBN). It is produced such that its preferential thermally conductive direction is aligned in the vertical axis, which facilitates direct thermal extraction, thereby addressing the increasing challenge of thermal crosstalk. The uniqueness of voBN comes from its h-BN nanocrystals where all their basal planes are aligned in the direction normal to the substrate plane. Using the 3ω method, we show that voBN exhibits high anisotropic thermal conductivity (TC) with a 16-fold difference between through-film TC and in-plane TC (respectively 4.26 and 0.26 W·m-1·K-1). Molecular dynamics simulations also concurred with the experimental data, showing that the origin of this anisotropic behavior is due to the nature of voBN's plane ordering. While the consistent vertical ordering provides an uninterrupted and preferred propagation path for phonons in the through-film direction, discontinuity in the lateral direction leads to a reduced in-plane TC. In addition, we also use COMSOL to simulate how the dielectric and thermal properties of voBN enable an increase in hot spot density up to 295% compared with SiO2, without any temperature increase.

  9. Annealing Effect on the Thermoelectric Properties of Bi2Te3 Thin Films Prepared by Thermal Evaporation Method

    Directory of Open Access Journals (Sweden)

    Jyun-Min Lin

    2013-01-01

    Full Text Available Bismuth telluride-based compounds are known to be the best thermoelectric materials within room temperature region, which exhibit potential applications in cooler or power generation. In this paper, thermal evaporation processes were adopted to fabricate the n-type Bi2Te3 thin films on SiO2/Si substrates. The influence of thermal annealing on the microstructures and thermoelectric properties of Bi2Te3 thin films was investigated in temperature range 100–250°C. The crystalline structures and morphologies were characterized by X-ray diffraction and field emission scanning electron microscope analyses. The Seebeck coefficients, electrical conductivity, and power factor were measured at room temperature. The experimental results showed that both the Seebeck coefficient and power factor were enhanced as the annealing temperature increased. When the annealing temperature increased to 250°C for 30 min, the Seebeck coefficient and power factor of n-type Bi2Te3-based thin films were found to be about −132.02 μV/K and 6.05 μW/cm·K2, respectively.

  10. Fabrication and Characterization of High-Crystalline Nanoporous ZnO Thin Films by Modified Thermal Evaporation System

    Science.gov (United States)

    Islam, M. S.; Hossain, M. F.; Razzak, S. M. A.; Haque, M. M.; Saha, D. K.

    2016-05-01

    The aim of this work is to fabricate high-crystalline nanoporous zinc oxide (ZnO) thin films by a modified thermal evaporation system. First, zinc thin films have been deposited on bare glass substrate by the modified thermal evaporation system with pressure of 0.05mbar, source-substrate distance of 3cm and source temperature 700∘C. Then, high-crystalline ZnO thin film is obtained by annealing at 500∘C for 2h in atmosphere. The prepared ZnO films are characterized with various deposition times of 10min and 20min. The structural property was investigated by X-ray diffractometer (XRD). The optical bandgap and absorbance/transmittance of these films are examined by ultraviolet/visible spectrophotometer. The surface morphological property has been observed by scanning electron microscope (SEM). ZnO films have showed uniform nanoporous surface with high-crystalline hexagonal wurtzite structure. The ZnO films prepared with 20min has excitation absorption-edge at 369nm, which is blueshifted with respect to the bulk absorption-edge appearing at 380nm. The gap energy of ZnO film is decreased from 3.14eV to 3.09eV with increase of the deposition time, which can enhance the excitation of ZnO films by the near visible light, and is suitable for the application of photocatalyst of waste water cleaning and polluted air purification.

  11. Effect of thermal annealing on structural and optical properties of In{sub 2}S{sub 3} thin films

    Energy Technology Data Exchange (ETDEWEB)

    Choudhary, Sonu, E-mail: sonuchoudhary1983@gmail.com [Department of Physics, Mohanlal Sukhadia University, Udaipur-313001 (India)

    2015-08-28

    There is a highly need of an alternate of toxic materials CdS for solar cell applications and indium sulfide is found the most suitable candidate to replace CdS due to its non-toxic and environmental friendly nature. In this paper, the effect of thermal annealing on the structural and optical properties of indium sulfide (In{sub 2}S{sub 3}) thin films is undertaken. The indium sulfide thin films of 121 nm were deposited on glass substrates employing thermal evaporation method. The films were subjected to the X-ray diffractometer and UV-Vis spectrophotometer respectively for structural and optical analysis. The XRD pattern show that the as-deposited thin film was amorphous in nature and crystallinity is found to be varied with annealing temperature. The optical analysis reveals that the optical band gap is varied with annealing. The optical parameters like absorption coefficient, extinction coefficient and refractive index were calculated. The results are in good agreement with available literature.

  12. Assessment of Uncertainties for the NIST 1016 mm Guarded-Hot-Plate Apparatus: Extended Analysis for Low-Density Fibrous-Glass Thermal Insulation.

    Science.gov (United States)

    Zarr, Robert R

    2010-01-01

    An assessment of uncertainties for the National Institute of Standards and Technology (NIST) 1016 mm Guarded-Hot-Plate apparatus is presented. The uncertainties are reported in a format consistent with current NIST policy on the expression of measurement uncertainty. The report describes a procedure for determination of component uncertainties for thermal conductivity and thermal resistance for the apparatus under operation in either the double-sided or single-sided mode of operation. An extensive example for computation of uncertainties for the single-sided mode of operation is provided for a low-density fibrous-glass blanket thermal insulation. For this material, the relative expanded uncertainty for thermal resistance increases from 1 % for a thickness of 25.4 mm to 3 % for a thickness of 228.6 mm. Although these uncertainties have been developed for a particular insulation material, the procedure and, to a lesser extent, the results are applicable to other insulation materials measured at a mean temperature close to 297 K (23.9 °C, 75 °F). The analysis identifies dominant components of uncertainty and, thus, potential areas for future improvement in the measurement process. For the NIST 1016 mm Guarded-Hot-Plate apparatus, considerable improvement, especially at higher values of thermal resistance, may be realized by developing better control strategies for guarding that include better measurement techniques for the guard gap thermopile voltage and the temperature sensors.

  13. Thermal conductivity of a graphite bipolar plate (BPP) and its thermal contact resistance with fuel cell gas diffusion layers: Effect of compression, PTFE, micro porous layer (MPL), BPP out-of-flatness and cyclic load

    Science.gov (United States)

    Sadeghifar, Hamidreza; Djilali, Ned; Bahrami, Majid

    2015-01-01

    This paper reports on measurements of thermal conductivity of a graphite bipolar plate (BPP) as a function of temperature and its thermal contact resistance (TCR) with treated and untreated gas diffusion layers (GDLs). The thermal conductivity of the BPP decreases with temperature and its thermal contact resistance with GDLs, which has been overlooked in the literature, is found to be dominant over a relatively wide range of compression. The effects of PTFE loading, micro porous layer (MPL), compression, and BPP out-of-flatness are also investigated experimentally. It is found that high PTFE loadings, MPL and even small BPP out-of-flatness increase the BPP-GDL thermal contact resistance dramatically. The paper also presents the effect of cyclic load on the total resistance of a GDL-BPP assembly, which sheds light on the behavior of these materials under operating conditions in polymer electrolyte membrane fuel cells.

  14. Thermal protection system gap heating rates of the Rockwell International flat plate heat transfer model (OH2A/OH2B)

    Science.gov (United States)

    Foster, T. F.; Lockman, W. K.; Grifall, W. J.

    1973-01-01

    Heat transfer data for the Rockwell International Flat Plate Thermocouple Model are presented. The model simulated the Space Shuttle Vehicle Thermal Protection System. Data were recorded for locations in and around various size gaps for various gap orientation configurations. The test was conducted at Mach 5.1 for free-stream Reynolds number per foot values from 500,000 to 1,500,000.

  15. Unique Crystal Orientation of Poly(ethylene oxide) Thin Films by Crystallization Using a Thermal Gradient

    DEFF Research Database (Denmark)

    Gbabode, Gabin; Delvaux, Maxime; Schweicher, Guillaume

    2017-01-01

    thermal gradient technique. Millimeter-size domains with crystallites uniformly, oriented in the direction of the thermal gradient are observed. Futhermore, the crystallites size and :orientation distribution are enhanced (e.g., increases and decreases, respectively) when film thickness is decreased......, to significantly decrease the distribution of crystal orientation obtained after crystallization using the thermal gradient technique....

  16. Laser-Scribed Photo-thermal Reduction of Graphene-Oxide for Thin Film Sensor Applications

    OpenAIRE

    Kazemzadeh, Rouzbeh

    2015-01-01

    In this thesis, a cost effective, simple and fast method of reduction of Graphene Oxide thin film is proposed. Graphene oxide is a non-conductive material intrinsically and one of the techniques to convert it to conductive material is using laser beam to remove oxygen groups from its surface, in other words, to reduce it. Laser parameters must be optimized for an effective and successful reduction. Thin film of non-conductive Graphene oxide is converted into conductive thin layer by fast lase...

  17. The STAT7 Code for Statistical Propagation of Uncertainties In Steady-State Thermal Hydraulics Analysis of Plate-Fueled Reactors

    Energy Technology Data Exchange (ETDEWEB)

    Dunn, Floyd E. [Argonne National Lab. (ANL), Argonne, IL (United States); Hu, Lin-wen [Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States). Nuclear Reactor Lab.; Wilson, Erik [Argonne National Lab. (ANL), Argonne, IL (United States)

    2016-12-01

    The STAT code was written to automate many of the steady-state thermal hydraulic safety calculations for the MIT research reactor, both for conversion of the reactor from high enrichment uranium fuel to low enrichment uranium fuel and for future fuel re-loads after the conversion. A Monte-Carlo statistical propagation approach is used to treat uncertainties in important parameters in the analysis. These safety calculations are ultimately intended to protect against high fuel plate temperatures due to critical heat flux or departure from nucleate boiling or onset of flow instability; but additional margin is obtained by basing the limiting safety settings on avoiding onset of nucleate boiling. STAT7 can simultaneously analyze all of the axial nodes of all of the fuel plates and all of the coolant channels for one stripe of a fuel element. The stripes run the length of the fuel, from the bottom to the top. Power splits are calculated for each axial node of each plate to determine how much of the power goes out each face of the plate. By running STAT7 multiple times, full core analysis has been performed by analyzing the margin to ONB for each axial node of each stripe of each plate of each element in the core.

  18. Numerical Study of Thermal and Flow Characteristics of Plate-Fin Heat Sink with Longitudinal Vortex Generator Installed on the Ground

    Directory of Open Access Journals (Sweden)

    Yen-Tso Chang

    2014-01-01

    Full Text Available This study applied the commercial software ANSYS CFD (FLUENT, for simulating the transient flow field and investigating the influence of each parameter of longitudinal vortex generators (LVGs on the thermal flux of a plate-fin heat sink. Vortex generator was set in front of plate-fin heat sink and under the channel, which was in common-flow-down (CFD and common-flow-up (CFU conditions, which have the result of vortex generator of delta winglet pair (DWP. In this study the parameters were varied, such as the minimum transverse distance between winglet pair, the attack angle of the vortex generator, fins number, the fin height, and the distance between the vortex generator and plate-fin. The coolant fluid flew into the fin-to-fin channel and pushed the vortex from different geometry toward the bottom. This phenomenon took off the heat from the plate to enhance the heat transfer. The numerical results indicated that the LVGs located close to the plate-fin heat sink are zero with the attack angle being 30°, presenting optimal overall conditions.

  19. Optical and Morphological Studies of Thermally Evaporated PTCDI-C8 Thin Films for Organic Solar Cell Applications

    Directory of Open Access Journals (Sweden)

    Ronak Rahimi

    2013-01-01

    Full Text Available PTCDI-C8 due to its relatively high photosensitivity and high electron mobility has attracted much attention in organic semiconductor devices. In this work, thin films of PTCDI-C8 with different thicknesses were deposited on silicon substrates with native silicon dioxide using a vacuum thermal evaporator. Several material characterization techniques have been utilized to evaluate the structure, morphology, and optical properties of these films. Their optical constants (refractive index and extinction coefficient have been extracted from the spectroscopic ellipsometry (SE. X-ray reflectivity (XRR and atomic force microscopy (AFM were employed to determine the morphology and structure as well as the thickness and roughness of the PTCDI-C8 thin films. These films revealed a high degree of structural ordering within the layers. All the experimental measurements were performed under ambient conditions. PTCDI-C8 films have shown to endure ambient condition which allows pots-deposition characterization.

  20. Deposition Time and Thermal Cycles of Fabricating Thin-wall Steel Parts by Double Electrode GMAW Based Additive Manufacturing

    Directory of Open Access Journals (Sweden)

    Yang Dongqing

    2017-01-01

    Full Text Available The deposition time for fabricating the thin-wall part as well as the peak temperature of the substrate during the process was analyzed in the double electrode gas metal arc welding (DE-GMAW based additive manufacturing (AM. The total deposition time and the interlayer idle time of the manufacturing process decreased with the increasing of the bypass current under the same interlayer temperature and the same deposition rate. The thermal cycling curves illustrated that the peak temperature of the substrate was lower in the DE-GMAW base AM under the same conditions. When depositing the thin-wall parts, the DE-GMAW based AM can reduce the heat input to the substrate and improve the fabrication efficiency, compared with the GMAW based AM.

  1. Thermal Quenching of Photoluminescence from Er-Doped GaN Thin Films

    National Research Council Canada - National Science Library

    Seo, J. T; Hoemmerich, U; Lee, D. C; Heikenfeld, J; Steckl, A. J; Zavada, J. M

    2002-01-01

    The green (537 and 558 nm) and near infrared (1.54 micrometers) photoluminescence (PL) spectra of Er-doped GaN thin films have been investigated as a function of temperature, excitation wavelength, and pump intensity...

  2. Preparation and properties of negative thermal expansion zirconium tungstate thin films deposited by radio frequency magnetron sputtering

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Hong-Fei; Cheng, Xiao-Nong; Zhang, Zhi-Ping [School of Materials Science and Engineering, Jiangsu University, Zhenjiang 212013 (China)

    2008-11-15

    Zirconium tungstate (ZrW{sub 2}O{sub 8}) thin films were deposited on quartz substrates by radio frequency magnetron sputtering followed by annealing at various temperatures. The effects of post-deposition annealing temperature on the phase, morphology and negative thermal expansion properties of the ZrW{sub 2}O{sub 8} thin films were investigated. X-ray diffraction data confirmed that the as-deposited ZrW{sub 2}O{sub 8} films were amorphous, and crystalline ZrW{sub 2}O{sub 8} films could be obtained at high annealing temperature. Trigonal ZrW{sub 2}O{sub 8} films could be prepared at 740 C and cubic ZrW{sub 2}O{sub 8} films could be prepared at 1200 C. The surface morphologies of the ZrW{sub 2}O{sub 8} thin films were evaluated using scanning electron microscopy. The results indicated that amorphous ZrW{sub 2}O{sub 8} films were uniform and dense, and the grain size of the crystalline ZrW{sub 2}O{sub 8} films became larger with increasing annealing temperature. The resulting cubic ZrW{sub 2}O{sub 8} films showed negative thermal expansion, the average value of thermal expansion coefficient being -8.18 x 10{sup -6} K{sup -1} in the temperature range 15-700 C. (copyright 2008 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  3. Plasma Spray-CVD: A New Thermal Spray Process to Produce Thin Films from Liquid or Gaseous Precursors

    Science.gov (United States)

    Gindrat, M.; Höhle, H.-M.; von Niessen, K.; Guittienne, Ph.; Grange, D.; Hollenstein, Ch.

    2011-06-01

    New dedicated coating processes which are based on the well-known LPPS™ technology but operating at lower work pressure (100 Pa) are being actively developed. These hybrid technologies contribute to improve the efficiencies in the turbine industry such as aero-engines and land-based gas turbines. They also have a great potential in the domain of new energy concepts in applications like Solid Oxide Fuel Cells, membranes, and photovoltaic with the adoption of new ways of producing coatings by thermal spray. Such processes include Plasma Spray-Thin Film (PS-TF) which gives the possibility to coat thin and dense layers from splats through a classical thermal spray approach but at high velocities (400-800 m/s) and enthalpy (8000-15000 kJ/kg). Plasma Spray-PVD (PS-PVD) which allows producing thick columnar-structured Thermal Barrier Coatings (100-300 μm) from the vapor phase with the employment of the high enthalpy gun and specific powder feedstock material. On the other hand, the Plasma Spray-CVD (PS-CVD) process uses modified conventional thermal spray components operated below 100 Pa which allows producing CVD-like coatings (article, we present an overview of the possibilities and limitations encountered while producing thin film coatings using liquid and gaseous precursors with this new type of low pressure plasma spray equipment and point out the challenges faced to obtain efficient injection and mixing of the precursors in the plasma jet. In particular, SiO x thin films from Hexamethyldisiloxane (HMDSO or C6H18OSi2) can be deposited on wafers at deposition rates of up to 35 nm/s at an efficiency of about 50%. The process was also used for producing metal oxide coatings (Al2O3, ZnO, and SnO2) by evaporating different metals in combination with an oxygen gas flow. The effect of process parameters on the deposition rate, coating build up, uniformity, and quality of the coatings are discussed. An overview of different potential applications of this new technology

  4. Design and Operation of an Optically-Accessible Modular Reactor for Diagnostics of Thermal Thin Film Deposition Processes.

    Science.gov (United States)

    Kimes, W A; Sperling, B A; Maslars, J E

    2015-01-01

    The design and operation of a simple, optically-accessible modular reactor for probing thermal thin film deposition processes, such as atomic layer deposition processes (ALD) and chemical vapor deposition (CVD), is described. This reactor has a nominal footprint of 225 cm(2) and a mass of approximately 6.6 kg, making it small enough to conveniently function as a modular component of an optical train. The design is simple, making fabrication straightforward and relatively inexpensive. Reactor operation is characterized using two infrared absorption measurements to determine exhaust times for tetrakis(dimethylamino)titanium and water, proto-typical ALD precursors, in a pressure and flow regime commonly used for ALD.

  5. Thermal-sprayed, thin-film pyrite cathodes for thermal batteries -- Discharge-rate and temperature studies in single cells

    Energy Technology Data Exchange (ETDEWEB)

    GUIDOTTI,RONALD A.; REINHARDT,FREDERICK W.; DAI,JINXIANG; XIAO,T. DANNY; REISNER,DAVID

    2000-05-25

    Using an optimized thermal-spray process, coherent, dense deposits of pyrite (FeS{sub 2}) with good adhesion were formed on 304 stainless steel substrates (current collectors). After leaching with CS{sub 2} to remove residual free sulfur, these served as cathodes in Li(Si)/FeS{sub 2} thermal cells. The cells were tested over a temperature range of 450 C to 550 C under baseline loads of 125 and 250 mA/cm{sup 2}, to simulate conditions found in a thermal battery. Cells built with such cathodes outperformed standard cells made with pressed-powder parts. They showed lower interracial resistance and polarization throughout discharge, with higher capacities per mass of pyrite. Post-treatment of the cathodes with Li{sub 2}O coatings at levels of >7% by weight of the pyrite was found to eliminate the voltage transient normally observed for these materials. Results equivalent to those of standard lithiated catholytes were obtained in this manner. The use of plasma-sprayed cathodes allows the use of much thinner cells for thermal batteries since only enough material needs to be deposited as the capacity requirements of a given application demand.

  6. High Mobility Flexible Amorphous IGZO Thin-Film Transistors with a Low Thermal Budget Ultra-Violet Pulsed Light Process.

    Science.gov (United States)

    Benwadih, M; Coppard, R; Bonrad, K; Klyszcz, A; Vuillaume, D

    2016-12-21

    Amorphous, sol-gel processed, indium gallium zinc oxide (IGZO) transistors on plastic substrate with a printable gate dielectric and an electron mobility of 4.5 cm(2)/(V s), as well as a mobility of 7 cm(2)/(V s) on solid substrate (Si/SiO2) are reported. These performances are obtained using a low temperature pulsed light annealing technique. Ultraviolet (UV) pulsed light system is an innovative technique compared to conventional (furnace or hot-plate) annealing process that we successfully implemented on sol-gel IGZO thin film transistors (TFTs) made on plastic substrate. The photonic annealing treatment has been optimized to obtain IGZO TFTs with significant electrical properties. Organic gate dielectric layers deposited on this pulsed UV light annealed films have also been optimized. This technique is very promising for the development of amorphous IGZO TFTs on plastic substrates.

  7. Thermal generation of spin current in epitaxial CoFe{sub 2}O{sub 4} thin films

    Energy Technology Data Exchange (ETDEWEB)

    Guo, Er-Jia, E-mail: ejguophysics@gmail.com, E-mail: klaeui@uni-mainz.de [Institut für Physik, Johannes Gutenberg-Universität Mainz, 55099 Mainz (Germany); Quantum Condensed Matter Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37830 (United States); Herklotz, Andreas [Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37830 (United States); Kehlberger, Andreas; Cramer, Joel; Jakob, Gerhard; Kläui, Mathias, E-mail: ejguophysics@gmail.com, E-mail: klaeui@uni-mainz.de [Institut für Physik, Johannes Gutenberg-Universität Mainz, 55099 Mainz (Germany)

    2016-01-11

    The longitudinal spin Seebeck effect (LSSE) has been investigated in high-quality epitaxial CoFe{sub 2}O{sub 4} (CFO) thin films. The thermally excited spin currents in the CFO films are electrically detected in adjacent Pt layers due to the inverse spin Hall effect. The LSSE signal exhibits a linear increase with increasing temperature gradient, yielding a LSSE coefficient of ∼100 nV/K at room temperature. The temperature dependence of the LSSE is investigated from room temperature down to 30 K, showing a significant reduction at low temperatures, revealing that the total amount of thermally generated magnons decreases. Furthermore, we demonstrate that the spin Seebeck effect is an effective tool to study the magnetic anisotropy induced by epitaxial strain, especially in ultrathin films with low magnetic moments.

  8. New spreading law of thin film liquids controlled by gravity and vdW forces under thermal fluctuations

    Science.gov (United States)

    Nesic, Svetozar; Cuerno Rejado, Rodolfo; Moro Egido, Esteban

    2013-11-01

    It has been shown that, in the regime controlled by surface tension, the spreading dynamics of a thin viscous fluid droplet changes significantly when it is subjected to thermal fluctuations. Technically, this has been accomplished through the incorporation of appropriate stochastic terms into the standard lubrication equation. In practice, it leads to a modification of the classic Tanner's law for spreading, with implications for Micro and Nanofluidic systems. We have recently found a new law of spreading for the same kind of systems, but in the gravity-dominated regime. Moreover, in the deteministic case a finite contact angle is formed when a van der Waals attractive force is introduced to the system and we show that there is a slight change in contact angle when thermal fluctuations are taken into account. Ph.D student and a member of GISC (http://matematicas.uc3m.es/index.php/gisc).

  9. Pressure Measurements in a PBX 9501 Gauged Acceptor When Impacted by a Steel Plate that is Accelerated by a Thermally Cooked Off PBX 9501 Charge

    Energy Technology Data Exchange (ETDEWEB)

    Forbes, J W; Garcia, F; Urtiew, P A; Vandersall, K S; Greenwood, D W; Tarver, C M

    2002-03-11

    Measuring the violence of a thermal explosion of a cased explosive is important for evaluating safety issues of explosive devices in fires. A sympathetic initiation scenario was studied here where a 9.0 cm diameter by 2.5 cm thick disc of PBX 9501 donor charge encased in a 304 stainless steel assembly was heated on top and bottom flat surfaces until it thermally exploded. The initial heating rate at the metal/explosive interface was 5 C per minute until it reaches 170 C; then this temperature is held for 35 minutes to allow temperature equilibration to within a few degrees throughout the explosive. The heating resumed at a rate of 1 C per minute until the PBX 9501 donor thermally exploded. A PBX 9501 acceptor charge with carbon resistor and manganin foil pressure gauges inserted at various depths was placed at a 10 cm standoff distance from the donor charge's top steel cover plate. Piezoelectric arrival time pins were placed in front of the acceptor surface to measure the velocity and shape of the impacting plate. The stainless steel cover plate of the donor charge had a nominal velocity of 0.55 {+-} 0.04 mm/{micro}s upon impact and was non-symmetrically warped. The impact of the tilted curved plate induced a three-dimensional compression wave into the acceptor. The rise times of the pressure waves were nominally 1.5 {micro}s with the closest carbon resistor gauges giving peak pressure of 10 kb that decayed to 3 kb for a wave run distance of 2.4 cm.

  10. Thin ice clouds in the Arctic: cloud optical depth and particle size retrieved from ground-based thermal infrared radiometry

    Directory of Open Access Journals (Sweden)

    Y. Blanchard

    2017-06-01

    Full Text Available Multiband downwelling thermal measurements of zenith sky radiance, along with cloud boundary heights, were used in a retrieval algorithm to estimate cloud optical depth and effective particle diameter of thin ice clouds in the Canadian High Arctic. Ground-based thermal infrared (IR radiances for 150 semitransparent ice clouds cases were acquired at the Polar Environment Atmospheric Research Laboratory (PEARL in Eureka, Nunavut, Canada (80° N, 86° W. We analyzed and quantified the sensitivity of downwelling thermal radiance to several cloud parameters including optical depth, effective particle diameter and shape, water vapor content, cloud geometric thickness and cloud base altitude. A lookup table retrieval method was used to successfully extract, through an optimal estimation method, cloud optical depth up to a maximum value of 2.6 and to separate thin ice clouds into two classes: (1 TIC1 clouds characterized by small crystals (effective particle diameter  ≤  30 µm, and (2 TIC2 clouds characterized by large ice crystals (effective particle diameter  >  30 µm. The retrieval technique was validated using data from the Arctic High Spectral Resolution Lidar (AHSRL and Millimeter Wave Cloud Radar (MMCR. Inversions were performed over three polar winters and results showed a significant correlation (R2 =  0.95 for cloud optical depth retrievals and an overall accuracy of 83 % for the classification of TIC1 and TIC2 clouds. A partial validation relative to an algorithm based on high spectral resolution downwelling IR radiance measurements between 8 and 21 µm was also performed. It confirms the robustness of the optical depth retrieval and the fact that the broadband thermal radiometer retrieval was sensitive to small particle (TIC1 sizes.

  11. A kinematic model for Afar Depression lithospheric thinning and its implications for hominid evolution: an exercise in plate-tectonic paleoanthropology

    Science.gov (United States)

    Redfield, T.; Often, M.; Wheeler, W. H.

    2002-12-01

    We present a detailed Nubia-Arabia-Somalia (NU-AR-SOM) kinematic reconstruction based on magnetic sea floor isochrons in the Gulf of Aden and Red Sea and piercing points along the Red Sea margins. The reconstruction is combined with digital topographic and depth-to-Moho data to constrain in 4D the Late Oligocene to present-day evolution of the Afar supra-Moho crust. Opposite end-member models for crustal evolution are described. We conclude that less than 20% of the present-day Afar supra-Moho crust was constructed by magmatic processes such as diking and underplating. The reconstructions indicate that the greater percentage of crustal thinning (extension) occurred before 6.2 Ma. We model the thinning of the effective elastic lithosphere that accompanied extension, and show that the regional-scale topographic development of the Afar depression was virtually complete by Mid Pliocene time. The plate-tectonic model has paleoanthropological implications. Prior to 6.2 Ma the proximal positions of NU-SOM, AR, and the Danakil block suggest subaerial conditions prevailed between Yemen and Ethiopia. Uninhibited Africa-Eurasia faunal exchange through Afar and Arabia (corroborated by isotopic and paleontologic data) was tectonically permissible until the time of the earliest hominids. Continued stretching caused the Afar land bridge(s) to disappear during Early to Mid Pliocene time. Primitive hominid populations living within the Afar Depression became isolated from AR sometime before ~3.2 Ma. With the plateau becoming less habitable due to long-term Late Neogene cooling, hominids that remained in the Afar Depression were required to adapt to a smaller range that was effectively bounded by the already well-developed NU-SOM escarpments and the newly opened Straits of Bab el Mandeb. The combination of high quality habitat,topographic confinement, and a gradual (tectonic) reduction in range, exacerbated by potentially severe fluctuations in local climate (well documented by land

  12. Influence of Strain on Thermal Conductivity of Silicon Nitride Thin Films

    Science.gov (United States)

    2012-03-02

    of resistance. One end of the aluminum heater (boundary 3) is provided with an electric potential (V = Vo ) and the opposite end (boundary 4) is...2007 Tunable thermal response of ZnO nanowires Nanotechnology 18 435706 [25] Shen S et al 2010 Polyethylene nanofibres with very high thermal

  13. Thermal recrystallization of physical vapor deposition based germanium thin films on bulk silicon (100)

    KAUST Repository

    Hussain, Aftab M.

    2013-08-16

    We demonstrate a simple, low-cost, and scalable process for obtaining uniform, smooth surfaced, high quality mono-crystalline germanium (100) thin films on silicon (100). The germanium thin films were deposited on a silicon substrate using plasma-assisted sputtering based physical vapor deposition. They were crystallized by annealing at various temperatures ranging from 700 °C to 1100 °C. We report that the best quality germanium thin films are obtained above the melting point of germanium (937 °C), thus offering a method for in-situ Czochralski process. We show well-behaved high-κ /metal gate metal-oxide-semiconductor capacitors (MOSCAPs) using this film. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  14. In-Situ Testing of the Thermal Diffusivity of Polysilicon Thin Films

    Directory of Open Access Journals (Sweden)

    Yi-Fan Gu

    2016-10-01

    Full Text Available This paper presents an intuitive yet effective in-situ thermal diffusivity testing structure and testing method. The structure consists of two doubly clamped beams with the same width and thickness but different lengths. When the electric current is applied through two terminals of one beam, the beam serves as thermal resistor and the resistance R(t varies as temperature rises. A delicate thermodynamic model considering thermal convection, thermal radiation, and film-to-substrate heat conduction was established for the testing structure. The presented in-situ thermal diffusivity testing structure can be fabricated by various commonly used micro electro mechanical systems (MEMS fabrication methods, i.e., it requires no extra customized processes yet provides electrical input and output interfaces for in-situ testing. Meanwhile, the testing environment and equipment had no stringent restriction, measurements were carried out at normal temperatures and pressures, and the results are relatively accurate.

  15. Thermoelectric thermal detectors based on ultra-thin heavily doped single-crystal silicon membranes

    Science.gov (United States)

    Varpula, Aapo; Timofeev, Andrey V.; Shchepetov, Andrey; Grigoras, Kestutis; Hassel, Juha; Ahopelto, Jouni; Ylilammi, Markku; Prunnila, Mika

    2017-06-01

    We present thermal detectors based on 40 nm-thick strain tuned single crystalline silicon membranes shaped into a heater area supported by narrow n- and p-doped beams, which also operate as a thermocouple. The electro-thermal characterization of the devices reveals a noise equivalent power of 13 pW/Hz1/2 and a thermal time constant of 2.5 ms. The high sensitivity of the devices is due to the high Seebeck coefficient of 0.39 mV/K and reduction of thermal conductivity of the Si beams from the bulk value. The performance enables fast and sensitive detection of low levels of thermal power and infrared radiation at room temperature. The devices operate in the Johnson-Nyquist noise limit of the thermocouple, and the performance improvement towards the operation close to the temperature fluctuation limit is discussed.

  16. Parallel experimental study of a novel super-thin thermal absorber based photovoltaic/thermal (PV/T system against conventional photovoltaic (PV system

    Directory of Open Access Journals (Sweden)

    Peng Xu

    2015-11-01

    Full Text Available Photovoltaic (PV semiconductor degrades in performance due to temperature rise. A super thin-conductive thermal absorber is therefore developed to regulate the PV working temperature by retrofitting the existing PV panel into the photovoltaic/thermal (PV/T panel. This article presented the parallel comparative investigation of the two different systems through both laboratory and field experiments. The laboratory evaluation consisted of one PV panel and one PV/T panel respectively while the overall field system involved 15 stand-alone PV panels and 15 retrofitted PV/T panels. The laboratory testing results demonstrated the PV/T panel could achieve the electrical efficiency of about 16.8% (relatively 5% improvement comparing with the stand-alone PV panel, and yield an extra amount of heat with thermal efficiency of nearly 65%. The field testing results indicated that the hybrid PV/T panel could enhance the electrical return of PV panels by nearly 3.5%, and increase the overall energy output by nearly 324.3%. Further opportunities and challenges were then discussed from aspects of different PV/T stakeholders to accelerate the development. It is expected that such technology could become a significant solution to yield more electricity, offset heating load freely and reduce carbon footprint in contemporary energy environment.

  17. DETECTION OF THERMAL SUBLETHAL INJURY IN ESCHERICHIA COLI VIA THE SELECTIVE MEDIUM PLATING TECHNIQUE: MECHANISMS AND IMPROVEMENTS

    Directory of Open Access Journals (Sweden)

    Laura Espina

    2016-08-01

    Full Text Available In food preservation, the selective medium plating technique (SMPT is commonly used in order to detect and quantify the amount of sublethally injured cells in their bacterial cytoplasmic membranes after inimical treatments. From an applicative point of view, this information is of use in the synergistic combination of different preservation technologies, so that cells that are sublethally injured after one or more processes can end up being entirely inactivated by other hurdle(s. However, little work has been done to explain the reasons for the inability of sublethally injured cells to outgrow in selective agar media (containing the osmolyte NaCl as a selective agent, whereas they are able to grow in non-selective agar media. This research could contribute to explain this technique’s limits. In the present paper, the performance of SMPT on Escherichia coli cells after heat treatments is explored by applying different selective agents in the recovery media, using several mutants lacking factors involved in osmoregulation, and also by examining the integrity of the cytoplasmic membrane. In view of the results, the possibility of a specific toxic effect of Na+ as the main mechanism under SMPT is discarded, and the same level of sublethal injury is detected using KCl instead of NaCl. The synthesis of the osmoprotectant trehalose determined the maximum osmotolerance of intact cells to the selective agents, but was not crucial in the quantification of sublethal injury. Moreover, the extent of sublethal injury detected via SMPT was directly correlated with the physical loss of integrity of the cell membrane as measured with the propidium iodide-exclusion technique when that dye was added before thermal treatments. The present work confirms the adequacy of SMPT as a tool for detecting the occurrence and quantity of sublethally injured cells and thus, for efficiently designing combined preservation treatments. Additionally, we propose the combination

  18. Growth of manganese sulfide (α-MnS) thin films by thermal vacuum evaporation: Structural, morphological and optical properties

    Energy Technology Data Exchange (ETDEWEB)

    Hannachi, Amira, E-mail: amira.hannachi88@gmail.com [MALTA-Consolider Team, Institut de Ciència dels Materials – Departamento de Fisica Aplicada, University of Valencia, E-46100 Burjassot, Valencia (Spain); Université de Tunis El-Manar, Faculté des Sciences de Tunis, Laboratoire de Chimie Analytique et Electrochimie, LR99ES15, 2092 Tunis (Tunisia); Segura, Alfredo [MALTA-Consolider Team, Institut de Ciència dels Materials – Departamento de Fisica Aplicada, University of Valencia, E-46100 Burjassot, Valencia (Spain); Maghraoui-Meherzi, Hager [Université de Tunis El-Manar, Faculté des Sciences de Tunis, Laboratoire de Chimie Analytique et Electrochimie, LR99ES15, 2092 Tunis (Tunisia)

    2016-09-15

    MnS thin films have been successfully prepared by thermal evaporation method at different substrate temperatures using different masses of MnS powder. The prepared films were characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray analysis (EDX) and UV–visible spectrophotometry. The XRD measurements show that the films crystallized in the pure α-MnS for substrate temperatures above 100 °C. The optical bandgap of thin films is found to be in the range of 3.2–3.3 eV. A factorial experimental design was used for determining the influence of the two experimental parameters on the films growth. - Highlights: • α-MnS films were deposited on glass and quartz substrates using the thermal evaporation technique. • The effect of substrate temperature on the properties of the MnS films has been studied. • The factorial design was used to determine the most influence parameters.

  19. Investigations of rapid thermal annealing induced structural evolution of ZnO: Ge nanocomposite thin films via GISAXS

    Energy Technology Data Exchange (ETDEWEB)

    Ceylan, Abdullah, E-mail: aceylanabd@yahoo.com [Department of Physics Eng., Hacettepe University, Beytepe, 06800 Ankara (Turkey); Ozcan, Yusuf [Department of Electricity and Energy, Pamukkale University, Denizli (Turkey); Orujalipoor, Ilghar [Department of Nanotechnology and Nanomedicine, Hacettepe University, Beytepe, 06800 Ankara (Turkey); Huang, Yen-Chih; Jeng, U-Ser [National Synchrotron Radiation Research Center, 101 Hsin-Ann Road, Hsinchu Science Park, Hsinchu, Taiwan (China); Ide, Semra [Department of Physics Eng., Hacettepe University, Beytepe, 06800 Ankara (Turkey); Department of Nanotechnology and Nanomedicine, Hacettepe University, Beytepe, 06800 Ankara (Turkey)

    2016-06-07

    In this work, we present in depth structural investigations of nanocomposite ZnO: Ge thin films by utilizing a state of the art grazing incidence small angle x-ray spectroscopy (GISAXS) technique. The samples have been deposited by sequential r.f. and d.c. sputtering of ZnO and Ge thin film layers, respectively, on single crystal Si(100) substrates. Transformation of Ge layers into Ge nanoparticles (Ge-np) has been initiated by ex-situ rapid thermal annealing of asprepared thin film samples at 600 °C for 30, 60, and 90 s under forming gas atmosphere. A special attention has been paid on the effects of reactive and nonreactive growth of ZnO layers on the structural evolution of Ge-np. GISAXS analyses have been performed via cylindrical and spherical form factor calculations for different nanostructure types. Variations of the size, shape, and distributions of both ZnO and Ge nanostructures have been determined. It has been realized that GISAXS results are not only remarkably consistent with the electron microscopy observations but also provide additional information on the large scale size and shape distribution of the nanostructured components.

  20. Pulsed laser deposition of piezoelectric lead zirconate titanate thin films maintaining a post-CMOS compatible thermal budget

    Science.gov (United States)

    Schatz, A.; Pantel, D.; Hanemann, T.

    2017-09-01

    Integration of lead zirconate titanate (Pb[Zrx,Ti1-x]O3 - PZT) thin films on complementary metal-oxide semiconductor substrates (CMOS) is difficult due to the usually high crystallization temperature of the piezoelectric perovskite PZT phase, which harms the CMOS circuits. In this work, a wafer-scale pulsed laser deposition tool was used to grow 1 μm thick PZT thin films on 150 mm diameter silicon wafers. Three different routes towards a post-CMOS compatible deposition process were investigated, maintaining a post-CMOS compatible thermal budget limit of 445 °C for 1 h (or 420 °C for 6 h). By crystallizing the perovskite LaNiO3 seed layer at 445 °C, the PZT deposition temperature can be lowered to below 400 °C, yielding a transverse piezoelectric coefficient e31,f of -9.3 C/m2. With the same procedure, applying a slightly higher PZT deposition temperature of 420 °C, an e31,f of -10.3 C/m2 can be reached. The low leakage current density of below 3 × 10-6 A/cm2 at 200 kV/cm allows for application of the post-CMOS compatible PZT thin films in low power micro-electro-mechanical-systems actuators.

  1. Effects of internal heat generation, thermal radiation and buoyancy force on a boundary layer over a vertical plate with a convective surface boundary condition

    Directory of Open Access Journals (Sweden)

    Tasawar Hayat

    2011-09-01

    Full Text Available In this paper we analyse the effects of internal heat generation, thermal radiation and buoyancy force on the laminar boundary layer about a vertical plate in a uniform stream of fluid under a convective surface boundary condition. In the analysis, we assumed that the left surface of the plate is in contact with a hot fluid whilst a stream of cold fluid flows steadily over the right surface; the heat source decays exponentially outwards from the surface of the plate. The similarity variable method was applied to the steady state governing non-linear partial differential equations, which were transformed into a set of coupled non-linear ordinary differential equations and were solved numerically by applying a shooting iteration technique together with a sixth-order Runge–Kutta integration scheme for better accuracy. The effects of the Prandtl number, the local Biot number, the internal heat generation parameter, thermal radiation and the local Grashof number on the velocity and temperature profiles are illustrated and interpreted in physical terms. A comparison with previously published results on similar special cases showed excellent agreement.

  2. Delamination, upper plate extension, and plate margin complexity

    Science.gov (United States)

    Ueda, Kosuke; Gerya, Taras; Willett, Sean

    2017-04-01

    We investigate the syn- and post-subduction margin evolution with respect to extension, lithospheric removal, and magmatic and topographic consequences by employing 3D geodynamic models. In all experiments, regions of extended partial melting are overlain by up to 3 km high plateaus. There is complex geometric entanglement between upper mantle, partially molten rocks, and lithosphere, which is thermally eroded, over hundreds of kilometers across the plate contact. A complex lithosphere-asthenosphere-boundary features elongated anomalies at scales of few tens to hundred kilometers. First-order, synthetic seismic anomaly patterns, based on thermodynamic velocities which are tabulated for model p,T conditions, are accordingly complex. Passive margin geometry variations in the lower plate effect consistent and inherited differences in dynamic evolution. Promontories along the margin tend to trigger three stages of evolution: 1) a magmatic arc; 2) a lower plate, eduction-like exhumation of buried continental crust in domal patterns of few tens of km wavelength; and subsequently, 3) the formation of extended zones on the upper plate which lack a lithospheric mantle, undergo partial extension, and feature lower crustal melting. Slab break-off is consistently favoured in locations where the lower plate margin is relatively recessed. Concerning the classical removal mechanisms, transitions and co-evolution between delamination, convective thinning, and upper-plate extension are gradual and these modes are not mutually exclusive. Almost complete mixed-mode removal and extension can be compared to the Aegean. Slab window formation by margin geometry variation produces characteristic uplift patterns that are comparable to the Apennines, where higher uplift rates could be a consequence of incipient necking of the slab below central Calabria.

  3. Improved Thermal-Vacuum Compatible Flat Plate Radiometric Souce for System-Level Testing of Optical Sensors

    Science.gov (United States)

    Schwarz, Mark A.; Kent, Craig J.; Bousquet, Robert; Brown, Steven W.

    2015-01-01

    This work describes the development of an improved vacuum compatible flat plate radiometric source used for characterizing and calibrating remote optical sensors, in situ, throughout their testing period. The original flat plate radiometric source was developed for use by the VIIRS instrument during the NPOESS Preparatory Project (NPP). Following this effort, the FPI has had significant upgrades in order to improve both the radiometric throughput and uniformity. Results of the VIIRS testing with the reconfigured FPI are reported and discussed.

  4. The design of high-temperature thermal conductivity measurements apparatus for thin sample size

    Directory of Open Access Journals (Sweden)

    Hadi Syamsul

    2017-01-01

    Full Text Available This study presents the designing, constructing and validating processes of thermal conductivity apparatus using steady-state heat-transfer techniques with the capability of testing a material at high temperatures. This design is an improvement from ASTM D5470 standard where meter-bars with the equal cross-sectional area were used to extrapolate surface temperature and measure heat transfer across a sample. There were two meter-bars in apparatus where each was placed three thermocouples. This Apparatus using a heater with a power of 1,000 watts, and cooling water to stable condition. The pressure applied was 3.4 MPa at the cross-sectional area of 113.09 mm2 meter-bar and thermal grease to minimized interfacial thermal contact resistance. To determine the performance, the validating process proceeded by comparing the results with thermal conductivity obtained by THB 500 made by LINSEIS. The tests showed the thermal conductivity of the stainless steel and bronze are 15.28 Wm-1K-1 and 38.01 Wm-1K-1 with a difference of test apparatus THB 500 are −2.55% and 2.49%. Furthermore, this apparatus has the capability to measure the thermal conductivity of the material to a temperature of 400°C where the results for the thermal conductivity of stainless steel is 19.21 Wm-1K-1 and the difference was 7.93%.

  5. Qualitative and quantitative high performance thin layer chromatography analysis of Calendula officinalis using high resolution plate imaging and artificial neural network data modelling.

    Science.gov (United States)

    Agatonovic-Kustrin, S; Loescher, Christine M

    2013-10-10

    Calendula officinalis, commonly known Marigold, has been traditionally used for its anti-inflammatory effects. The aim of this study was to investigate the capacity of an artificial neural network (ANN) to analyse thin layer chromatography (TLC) chromatograms as fingerprint patterns for quantitative estimation of chlorogenic acid, caffeic acid and rutin in Calendula plant extracts. By applying samples with different weight ratios of marker compounds to the system, a database of chromatograms was constructed. A hundred and one signal intensities in each of the HPTLC chromatograms were correlated to the amounts of applied chlorogenic acid, caffeic acid, and rutin using an ANN. The developed ANN correlation was used to quantify the amounts of 3 marker compounds in calendula plant extracts. The minimum quantifiable level (MQL) of 610, 190 and 940 ng and the limit of detection (LD) of 183, 57 and 282 ng were established for chlorogenic, caffeic acid and rutin, respectively. A novel method for quality control of herbal products, based on HPTLC separation, high resolution digital plate imaging and ANN data analysis has been developed. The proposed method can be adopted for routine evaluation of the phytochemical variability in calendula extracts. Copyright © 2013 Elsevier B.V. All rights reserved.

  6. Morphogenesis of thin hyperelastic plates: A constitutive theory of biological growth in the Föppl-von Kármán limit

    Science.gov (United States)

    Dervaux, Julien; Ciarletta, Pasquale; Ben Amar, Martine

    2009-03-01

    The shape of plants and other living organisms is a crucial element of their biological functioning. Morphogenesis is the result of complex growth processes involving biological, chemical and physical factors at different temporal and spatial scales. This study aims at describing stresses and strains induced by the production and reorganization of the material. The mechanical properties of soft tissues are modeled within the framework of continuum mechanics in finite elasticity. The kinematical description is based on the multiplicative decomposition of the deformation gradient tensor into an elastic and a growth term. Using this formalism, the authors have studied the growth of thin hyperelastic samples. Under appropriate assumptions, the dimensionality of the problem can be reduced, and the behavior of the plate is described by a two-dimensional surface. The results of this theory demonstrate that the corresponding equilibrium equations are of the Föppl-von Kármán type where growth acts as a source of mean and Gaussian curvatures. Finally, the cockling of paper and the rippling of a grass blade are considered as two examples of growth-induced pattern formation.

  7. Thermal conductivity of some common forest fuels

    Science.gov (United States)

    G.M. Byram; W.L. Fons

    1952-01-01

    This study was designed to obtain thermal conductivity of som common forest fuels which hitherto had defied such efforts because of their shape, size, or structure. Dry leaves and decayed. wood (punk) were modified so that conductivity measurements could be made by a thin plate uni-directional heat flow calibration stand, Resultss of these measurements are compatible...

  8. HREM investigation of the constitution and the crystallography of thin thermal oxide layers on iron

    DEFF Research Database (Denmark)

    Graat, P.C.J.; Brongers, M.P.H.; Zandbergen, H.W.

    1997-01-01

    /ferrite and a Shoji-Nishiyama-type orientation relationship for hematite/magnetite were observed. At several locations cracks close to and parallel to the interface with the substrate were observed within Fe3O4. Oxidation of iron samples that were covered with an (hydro)oxide film prior to oxidation yielded thin...

  9. Thermal and structural properties of spray pyrolysed CdS thin film

    Indian Academy of Sciences (India)

    Unknown

    The thin film cadmium sulphide solar cell has for several years been considered to be a promising .... is placed in the photoacoustics (PA) cell and the mike is placed very close to the sample on the glass slide. ... With this, following Rosencwaig and Gersho (1975) theory, the phase of the signal with respect to the reference.

  10. Bending and stretching of plates

    CERN Document Server

    Mansfield, E H; Hemp, W S

    1964-01-01

    The Bending and Stretching of Plates deals with elastic plate theory, particularly on small- and large-deflexion theory. Small-deflexion theory concerns derivation of basic equations, rectangular plates, plates of various shapes, plates whose boundaries are amenable to conformal transformation, plates with variable rigidity, and approximate methods. Large-deflexion theory includes general equations and some exact solutions, approximate methods in large-deflexion theory, asymptotic large-deflexion theories for very thin plates. Asymptotic theories covers membrane theory, tension field theory, a

  11. Three-Dimensional Thermal Boundary Layer Corrections for Circular Heat Flux Gauges Mounted in a Flat Plate with a Surface Temperature Discontinuity

    Science.gov (United States)

    Kandula, M.; Haddad, G. F.; Chen, R.-H.

    2006-01-01

    Three-dimensional Navier-Stokes computational fluid dynamics (CFD) analysis has been performed in an effort to determine thermal boundary layer correction factors for circular convective heat flux gauges (such as Schmidt-Boelter and plug type)mounted flush in a flat plate subjected to a stepwise surface temperature discontinuity. Turbulent flow solutions with temperature-dependent properties are obtained for a free stream Reynolds number of 1E6, and freestream Mach numbers of 2 and 4. The effect of gauge diameter and the plate surface temperature have been investigated. The 3-D CFD results for the heat flux correction factors are compared to quasi-21) results deduced from constant property integral solutions and also 2-D CFD analysis with both constant and variable properties. The role of three-dimensionality and of property variations on the heat flux correction factors has been demonstrated.

  12. Validation of a simple dynamic thermal performance characterization model based on the piston flow concept for flat-plate solar collectors

    DEFF Research Database (Denmark)

    Deng, Jie; Yang, Ming; Ma, Rongjiang

    2016-01-01

    . (2012) for the model turns out to be the collector static response time constant τC by analytical derivation. The nonlinear least squares method is applied to determine the characteristic parameters of a flat-plate solar air collector previously tested by the authors. Then the obtained parameters...... al. (2016a) is also considered. The results show that the prediction performance of the simple dynamic model is nearly as accurate as the ODE numerical solution and the TIM by Deng et al. (2016a) except some special conditions such as sharply changed solar irradiance and collector inlet temperature.......A simple dynamic characterization model of flat-plate solar collectors based on the piston flow concept is used both to identify the collector characteristic parameters and to predict the dynamic thermal performance. The heat transport time originally defined as (1 − e−1)−1τC by Amrizal et al...

  13. The influence of nitrogen and oxygen additions on the thermal characteristics of aluminium-based thin films

    Energy Technology Data Exchange (ETDEWEB)

    Borges, J., E-mail: joelborges@fisica.uminho.pt [Centro de Física, Universidade do Minho, Campus de Gualtar, 4710-057 Braga (Portugal); Department of Control Engineering, Faculty of Electrical Engineering, Czech Technical University in Prague, Technická 2, Prague 6 (Czech Republic); Macedo, F. [Centro de Física, Universidade do Minho, Campus de Gualtar, 4710-057 Braga (Portugal); Couto, F.M. [Physics Sciences Laboratory, Norte Fluminense State University, 28013-602 Campos–RJ (Brazil); Rodrigues, M.S.; Lopes, C. [Centro de Física, Universidade do Minho, Campus de Gualtar, 4710-057 Braga (Portugal); Instituto Pedro Nunes, Laboratório de Ensaios, Desgaste e Materiais, Rua Pedro Nunes, 3030-199 Coimbra (Portugal); Pedrosa, P. [Centro de Física, Universidade do Minho, Campus de Gualtar, 4710-057 Braga (Portugal); SEG-CEMUC, Mechanical Engineering Department, University of Coimbra, 3030-788 Coimbra (Portugal); Universidade do Porto, Faculdade de Engenharia, Departamento de Engenharia Metalúrgica e de Materiais, Rua Dr. Roberto Frias, s/n, 4200-465 Porto (Portugal); Polcar, T. [Department of Control Engineering, Faculty of Electrical Engineering, Czech Technical University in Prague, Technická 2, Prague 6 (Czech Republic); Engineering Materials & nCATS, FEE, University of Southampton, Highfield Campus, SO17 1BJ, Southampton (United Kingdom); Marques, L.; Vaz, F. [Centro de Física, Universidade do Minho, Campus de Gualtar, 4710-057 Braga (Portugal)

    2015-08-01

    The ternary aluminium oxynitride (AlN{sub x}O{sub y}) system offers the possibility to obtain a wide range of properties by tailoring the ratio between pure Al, AlN{sub x} and AlO{sub y} and therefore opening a significant number of possible applications. In this work the thermal behaviour of AlN{sub x}O{sub y} thin films was analysed by modulated infrared radiometry (MIRR), taking as reference the binary AlO{sub y} and AlN{sub x} systems. MIRR is a non-contact and non-destructive thermal wave measurement technique based on the excitation, propagation and detection of temperature oscillations of very small amplitudes. The intended change of the partial pressure of the reactive gas (N{sub 2} and/or O{sub 2}) influenced the target condition and hence the deposition characteristics which, altogether, affected the composition and microstructure of the films. Based on the MIRR measurements and their qualitative and quantitative interpretation, some correlations between the thermal transport properties of the films and their chemical/physical properties have been found. Furthermore, the potential of such technique applied in this oxynitride system, which present a wide range of different physical responses, is also discussed. The experimental results obtained are consistent with those reported in previous works and show a high potential to fulfil the demands needed for the possible applications of the systems studied. They are clearly indicative of an adequate thermal response if this particular thin film system is aimed to be applied in small sensor devices or in electrodes for biosignal acquisition, such as those for electroencephalography or electromyography as it is the case of the main research area that is being developed in the group. - Highlights: • AlN{sub x}, AlO{sub y} and AlN{sub x}O{sub y} films were deposited by magnetron sputtering. • Discharge characteristics were compared between systems. • Different x and y coefficients were obtained.

  14. Thermal aging effect of vanadyl acetylacetonate precursor for deposition of VO{sub 2} thin films with thermochromic properties

    Energy Technology Data Exchange (ETDEWEB)

    Yu, Jung-Hoon [Department of Chemistry, Sungkyunkwan University, 440-746 Suwon (Korea, Republic of); Nam, Sang-Hun [Institute of Basic Science, Sungkyunkwan University, 440-746 Suwon (Korea, Republic of); Kim, Donguk; Kim, Minha [School of Electronic and Electrical Engineering, Sungkyunkwan University (Korea, Republic of); Seo, Hyeon Jin; Ro, Yu Hyeon [Department of Chemistry, Sungkyunkwan University, 440-746 Suwon (Korea, Republic of); Joo, Yong Tae [YOUNG DO Glass Industry Co., Ltd., Jeongeup (Korea, Republic of); Lee, Jaehyeong [School of Electronic and Electrical Engineering, Sungkyunkwan University (Korea, Republic of); Boo, Jin-Hyo, E-mail: jhboo@skku.edu [Department of Chemistry, Sungkyunkwan University, 440-746 Suwon (Korea, Republic of); Institute of Basic Science, Sungkyunkwan University, 440-746 Suwon (Korea, Republic of)

    2016-10-15

    Highlights: • 7 day aged VO(acac){sub 2} sol shows enhanced adhesivity on the SiO{sub 2} compared with non-aged sol. • The aging process has significantly affected the morphologies of VO{sub 2} films. • From the FT-IR spectra, thermal aging process provides the deformation of precursor. • The metal insulator transition (MIT) efficiency (ΔT{sub at2000} {sub nm}) reached a maximum value of 51% at 7 day aging. • Thermal aging process could shorten the aging time of sol solution. - Abstract: Thermochromic properties of vanadium dioxide (VO{sub 2}) have been studied extensively due to their IR reflection applications in energy smart windows. In this paper, we studied the optical switching property of VO{sub 2} thin film, depending on the thermal aging time of the vanadyl acetylacetonate (VO(acac){sub 2}) precursor. We found the alteration of the IR spectra of the precursor by tuning the aging time as well as heat treatments of the precursor. An aging effect of vanadium precursor directly affects the morphologies, optical switching property and crystallinity of VO{sub 2} films. The optimum condition was achieved at the 7 day aging time with metal insulator transition (MIT) efficiency of 50%.

  15. Thin Film Williamson Nanofluid Flow with Varying Viscosity and Thermal Conductivity on a Time-Dependent Stretching Sheet

    Directory of Open Access Journals (Sweden)

    Waris Khan

    2016-11-01

    Full Text Available This article describes the effect of thermal radiation on the thin film nanofluid flow of a Williamson fluid over an unsteady stretching surface with variable fluid properties. The basic governing equations of continuity, momentum, energy, and concentration are incorporated. The effect of thermal radiation and viscous dissipation terms are included in the energy equation. The energy and concentration fields are also coupled with the effect of Dufour and Soret. The transformations are used to reduce the unsteady equations of velocity, temperature and concentration in the set of nonlinear differential equations and these equations are tackled through the Homotopy Analysis Method (HAM. For the sake of comparison, numerical (ND-Solve Method solutions are also obtained. Special attention has been given to the variable fluid properties’ effects on the flow of a Williamson nanofluid. Finally, the effect of non-dimensional physical parameters like thermal conductivity, Schmidt number, Williamson parameter, Brinkman number, radiation parameter, and Prandtl number has been thoroughly demonstrated and discussed.

  16. Effect of Si additions on thermal stability and the phase transition sequence of sputtered amorphous alumina thin films

    Energy Technology Data Exchange (ETDEWEB)

    Bolvardi, H.; Baben, M. to; Nahif, F.; Music, D., E-mail: music@mch.rwth-aachen.de; Schnabel, V.; Shaha, K. P.; Mráz, S.; Schneider, J. M. [Materials Chemistry, RWTH Aachen University, Kopernikusstr. 10, D-52074 Aachen (Germany); Bednarcik, J.; Michalikova, J. [Deutsches Elektronen Synchrotron DESY, FS-PE group, Notkestrasse 85, D-22607 Hamburg (Germany)

    2015-01-14

    Si-alloyed amorphous alumina coatings having a silicon concentration of 0 to 2.7 at. % were deposited by combinatorial reactive pulsed DC magnetron sputtering of Al and Al-Si (90-10 at. %) split segments in Ar/O{sub 2} atmosphere. The effect of Si alloying on thermal stability of the as-deposited amorphous alumina thin films and the phase formation sequence was evaluated by using differential scanning calorimetry and X-ray diffraction. The thermal stability window of the amorphous phase containing 2.7 at. % of Si was increased by more than 100 °C compared to that of the unalloyed phase. A similar retarding effect of Si alloying was also observed for the α-Al{sub 2}O{sub 3} formation temperature, which increased by more than 120 °C. While for the latter retardation, the evidence for the presence of SiO{sub 2} at the grain boundaries was presented previously, this obviously cannot explain the stability enhancement reported here for the amorphous phase. Based on density functional theory molecular dynamics simulations and synchrotron X-ray diffraction experiments for amorphous Al{sub 2}O{sub 3} with and without Si incorporation, we suggest that the experimentally identified enhanced thermal stability of amorphous alumina with addition of Si is due to the formation of shorter and stronger Si–O bonds as compared to Al–O bonds.

  17. Influence of an anomalous dimension effect on thermal instability in amorphous-InGaZnO thin-film transistors

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Kuan-Hsien; Chou, Wu-Ching, E-mail: tcchang3708@gmail.com, E-mail: wuchingchou@mail.nctu.edu.tw [Department of Electrophysics, National Chiao Tung University, Hsin-chu 300, Taiwan (China); Chang, Ting-Chang, E-mail: tcchang3708@gmail.com, E-mail: wuchingchou@mail.nctu.edu.tw [Department of Physics, National Sun Yat-Sen University, Kaohsiung 804, Taiwan (China); Advanced Optoelectronics Technology Center, National Cheng Kung University, Taiwan (China); Chen, Hua-Mao; Tai, Ya-Hsiang [Department of Photonics and Institute of Electro-Optical Engineering, National Chiao Tung University, Hsin-chu 300, Taiwan (China); Tsai, Ming-Yen; Hung, Pei-Hua; Chu, Ann-Kuo [Department of Photonics, National Sun Yat-Sen University, Kaohsiung 804, Taiwan (China); Wu, Ming-Siou; Hung, Yi-Syuan [Department of Electronics Engineering, National Chiao Tung University, Hsin-Chu 300, Taiwan (China); Hsieh, Tien-Yu [Department of Physics, National Sun Yat-Sen University, Kaohsiung 804, Taiwan (China); Yeh, Bo-Liang [Advanced Display Technology Research Center, AU Optronics, No.1, Li-Hsin Rd. 2, Hsinchu Science Park, Hsin-Chu 30078, Taiwan (China)

    2014-10-21

    This paper investigates abnormal dimension-dependent thermal instability in amorphous indium-gallium-zinc-oxide (a-IGZO) thin-film transistors. Device dimension should theoretically have no effects on threshold voltage, except for in short channel devices. Unlike short channel drain-induced source barrier lowering effect, threshold voltage increases with increasing drain voltage. Furthermore, for devices with either a relatively large channel width or a short channel length, the output drain current decreases instead of saturating with an increase in drain voltage. Moreover, the wider the channel and the shorter the channel length, the larger the threshold voltage and output on-state current degradation that is observed. Because of the surrounding oxide and other thermal insulating material and the low thermal conductivity of the IGZO layer, the self-heating effect will be pronounced in wider/shorter channel length devices and those with a larger operating drain bias. To further clarify the physical mechanism, fast I{sub D}-V{sub G} and modulated peak/base pulse time I{sub D}-V{sub D} measurements are utilized to demonstrate the self-heating induced anomalous dimension-dependent threshold voltage variation and on-state current degradation.

  18. The effects of convection and oxygen presence on thermal testing of thin-shelled Celotex{trademark}-based packages

    Energy Technology Data Exchange (ETDEWEB)

    Feldman, M.R.

    1994-06-01

    Several experiments were performed in an attempt to determine the effects of both convection and oxygen levels during hypothetical thermal accident testing of thin-shelled Celotex{trademark}-based packages in furnaces. Obsolete DT-22 packages were used and experiments were performed in two separate fumaces, one gas-fired and one electric, each of which has previously been used for this type of testing. Oxygen levels were varied and measured in the gas-fired furnace while the electric fumace was operated in a standard manner. The gas-fired fumace is constructed so as to induce a very strong convective field within. After testing, the packages were evaluated by several methods to determine the effects of the thermal testing on the package. In general, there were no differences found for the packages tested in the two different furnaces or for packages tested in the same furnace under different conditions. Therefore, after careful consideration, it is concluded that thermal testing can still be performed in electric furnaces in which the oxygen supply is not refurbished and there is no forced convection heat transfer.

  19. The method used for justification of engineering solutions for multistage plate-type mufflers attached to gas-air ducts of thermal power plants

    Science.gov (United States)

    Tupov, V. B.

    2013-08-01

    This paper describes technical and economic problems associated with the selection of designs of mufflers attached to gas-air ducts of thermal power plants. A method is suggested that makes it possible to determine the dimensions of each stage of plate-type mufflers on the basis of achieving the lowest total discounted costs in order to provide the required acoustical performance at a permissible aerodynamic resistance of a muffler. The condition of the lowest total discounted costs for a multistage muffler, which is valid for different types of mufflers, has been obtained.

  20. Thermal stability of tungsten-boron-nitride thin film as diffusion barrier

    CERN Document Server

    Park, Y K; Kim, Y T; Lee, C W

    2000-01-01

    The electrical and the structural properties of tungsten boron nitride (W-B-N) thin films were studied to investigate the effects of boron and nitrogen in the 10000 A W-B-N diffusion barrier. The W-B-N thin films were deposited by using the RF magnetron sputtering method. The impurities provided a stuffing effect that was very effective for preventing interdiffusion between the interconnection metal and the silicon during the subsequent high-temperature annealing process. The resistivities of the W-B-N thin films were in the range of 140 - 406 mu OMEGA-cm, depending on the partial pressure ratio of the N sub 2 gas and the RF power density of the W sub 2 B sub 5 target. XRD and electrical property analyses showed that the W-B-N barrier did not react with Si during the annealing in N sub 2 gas ambient, even for annealing at 1000 .deg. C for 30 min.

  1. Electrical and Optical Properties of GeSi−:H Thin Films Prepared by Thermal Evaporation Method

    Directory of Open Access Journals (Sweden)

    A. A. J. Al-Douri

    2010-01-01

    Full Text Available Thin a-GeSi1−:H films were grown successfully by fabrication of designated ingot followed by evaporation onto glass slides. A range of growth conditions, Ge contents, dopant concentration (Al and As, and substrate temperature, were employed. Stoichiometry of the thin films composition was confirmed using standard surface techniques. The structure of all films was amorphous. Film composition and deposition parameters were investigated for their bearing on film electrical and optical properties. More than one transport mechanism is indicated. It was observed that increasing substrate temperature, Ge contents, and dopant concentration lead to a decrease in the optical energy gap of those films. The role of the deposition conditions on values of the optical constants was determined. Accordingly, models of the density of states for the Ge0.5Si0.5:H thin films as pure, doped with 3.5% of Al (p-type and that doped with 3.5% As (n-type, were proposed.

  2. Thermal conductivity of nano-grained SrTiO3 thin films

    Science.gov (United States)

    Foley, Brian M.; Brown-Shaklee, Harlan J.; Duda, John C.; Cheaito, Ramez; Gibbons, Brady J.; Medlin, Doug; Ihlefeld, Jon F.; Hopkins, Patrick E.

    2012-12-01

    We measure the thermal conductivities of nano-grained strontium titanate (ng-SrTiO3) films deposited on sapphire substrates via time-domain thermoreflectance. The 170 nm thick oxide films of varying grain-size were prepared from a chemical solution deposition process. We find that the thermal conductivity of ng-SrTiO3 decreases with decreasing average grain size and attribute this to increased phonon scattering at grain boundaries. Our data are well described by a model that accounts for the spectral nature of anharmonic Umklapp scattering along with grain boundary scattering and scattering due to the film thickness.

  3. Thin film thermoelectric metal-organic framework with high Seebeck coefficient and low thermal conductivity (Presentation Recording)

    Science.gov (United States)

    Erickson, Kristopher J.; Leonard, Francois; Stavila, Vitalie N.; Foster, Michael E.; Spataru, Catalin D.; Jones, Reese; Foley, Brian; Hopkins, Patrick; Allendorf, Mark D.; Talin, A. Alec

    2015-08-01

    Inorganic, low bandgap semiconductors such as Bi2Te3 have adequate efficiency for some thermoelectric energy conversion applications, but have not been more widely adopted because they are difficult to deposit over complex and/or high surface area structures, are not eco-friendly, and are too expensive. As an alternative, conducting polymers have recently attracted much attention for thermoelectric applications motivated by their low material cost, ease of processability, non-toxicity, and low thermal conductivity. Metal-organic frameworks (MOFs), which are extended, crystalline compounds consisting of metal ions interconnected by organic ligands, share many of the advantages of all-organic polymers including solution processability and low thermal conductivity. Additionally, MOFs and Guest@MOF materials offer higher thermal stability (up to ~300 °C in some cases) and have long-range crystalline order which should improve charge mobility. A potential advantage of MOFs and Guest@MOF materials over all-organic polymers is the opportunity for tuning the electronic structure through appropriate choice of metal and ligand, which could solve the long-standing challenge of finding stable, high ZT n-type organic semiconductors. In our presentation, we report on thermoelectric measurements of electrically conducting TCNQ@Cu3(BTC)2 thin films deposited using a room-temperature, solution-based method, which reveal a large, positive Seebeck coefficient. Furthermore, we use time-dependent thermoreflectance (TDTR) to measure the thermal conductivity of the films, which is found to have a low value due to the presence of disorder, as suggested by molecular dynamics simulations. In addition to establishing the thermoelectric figure of merit, the thermoelectric measurements reveal for the first time that holes are the majority carriers in TCNQ@Cu3(BTC)2.

  4. Phonon scattering mechanisms dictating the thermal conductivity of lead zirconate titanate (PbZr1-xTixO3) thin films across the compositional phase diagram

    Science.gov (United States)

    Foley, Brian M.; Paisley, Elizabeth A.; DiAntonio, Christopher; Chavez, Tom; Blea-Kirby, Mia; Brennecka, Geoff; Gaskins, John T.; Ihlefeld, Jon F.; Hopkins, Patrick E.

    2017-05-01

    This work represents a thorough investigation of the thermal conductivity (κ) in both thin film and bulk PbZr1-xTixO3 (PZT) across the compositional phase diagram. Given the technological importance of PZT as a superb piezoelectric and ferroelectric material in devices and systems impacting a wide array of industries, this research serves to fill the gap in knowledge regarding the thermal properties. The thermal conductivities of both thin film and bulk PZT are found to vary by a considerable margin as a function of composition x. Additionally, we observe a discontinuity in κ in the vicinity of the morphotropic phase boundary (MPB, x = 0.48) where there is a 20%-25% decrease in κ in our thin film data, similar to that found in literature data for bulk PZT. The comparison between bulk and thin film materials highlights the sensitivity of κ to size effects such as film thickness and grain size even in disordered alloy/solid-solution materials. A model for the thermal conductivity of PZT as a function of composition ( κ ( x)) is presented, which enables the application of the virtual crystal approximation for alloy-type material systems with very different crystals structures, resulting in differing temperature trends for κ. We show that in the case of crystalline solid-solutions where the thermal conductivity of one of the parent materials exhibits glass-like temperature trends the compositional dependence of thermal conductivity is relatively constant for most values of x. This is in stark contrast with the typical trends of thermal conductivity with x in alloys, where the thermal conductivity increases dramatically as the composition of the alloy or solid-solution approaches that of a pure parent materials (i.e., as x = 0 or 1).

  5. A hybrid surface modification method on copper wire braids for enhancing thermal performance of ultra-thin heat pipes

    Science.gov (United States)

    Sheng, W. K.; Lin, H. T.; Wu, C. H.; Kuo, L. S.; Chen, P. H.

    2017-02-01

    Copper is the most widely used material in heat pipe manufacturing. Since the capability of wick structures inside a heat pipe will dominate its thermal performance, in this study, we introduce a hybrid surface modification method on the copper wire braids being inserted as wick structure into an ultra-thin heat pipe. The hybrid method is the combination of a chemical-oxidation-based method and a sol-gel method with nanoparticles being dip-coated onto the braid. The experimental data show that braids under hybrid treatment perform higher water rising speed than the oxidized braids while owning higher water net weight than those braids being only dip-coated with nanoparticle.

  6. Method for measuring thermal accommodation coefficients of gases on thin film surfaces using a MEMS sensor structure

    Energy Technology Data Exchange (ETDEWEB)

    Grau, Mario, E-mail: mario.grau@hs-rm.de; Völklein, Friedemann; Meier, Andreas; Kunz, Christina; Heidler, Jonas [Institute for Microtechnologies, RheinMain University of Applied Sciences, Rüsselsheim 65428 (Germany); Woias, Peter [Department of Microsystems Engineering, University of Freiburg, Freiburg 79110 (Germany)

    2016-07-15

    A method for measuring the thermal accommodation coefficient α for surface-/gas interfaces is presented. It allows the determination of α for thin films produced by a variety of deposition technologies, such as chemical vapor deposition, physical vapor deposition, and atomic layer deposition (ALD). The setup is based on two microelectromechanical systems (MEMS) Pirani sensors facing each other in a defined positioning. Because these MEMS sensors show a very high sensitivity in their individual molecular flow regimes, it is possible to measure the accommodation coefficients of gases without the disturbing influence of the transition regime. This paper presents the analytical background and the actual measurement principle. The results for air and nitrogen molecules on sputtered Au and Pt surfaces are presented.

  7. Design and Operation of an Optically-Accessible Modular Reactor for Diagnostics of Thermal Thin Film Deposition Processes

    Science.gov (United States)

    Kimes, W. A.; Sperling, B. A.; Maslars, J. E.

    2015-01-01

    The design and operation of a simple, optically-accessible modular reactor for probing thermal thin film deposition processes, such as atomic layer deposition processes (ALD) and chemical vapor deposition (CVD), is described. This reactor has a nominal footprint of 225 cm2 and a mass of approximately 6.6 kg, making it small enough to conveniently function as a modular component of an optical train. The design is simple, making fabrication straightforward and relatively inexpensive. Reactor operation is characterized using two infrared absorption measurements to determine exhaust times for tetrakis(dimethylamino)titanium and water, proto-typical ALD precursors, in a pressure and flow regime commonly used for ALD. PMID:26958438

  8. Half-Space Temperature Field with a Movable Thermally Thin-Coated Boundary Under External Heat Flux

    Directory of Open Access Journals (Sweden)

    P. A. Vlasov

    2014-01-01

    Full Text Available In engineering practice analytical methods of the mathematical theory of heat conduction hold a special place. This is due to many reasons, in particular, because of the fact that the solutions of the relevant problems represented in analytically closed form, can be used not only for a parametric analysis of the studied temperature field and to explore the specific features of its formation, but also to test the developed computational algorithms, which are aimed at solving real-world application heat and mass transfer problems. Difficulties arising when using the analytical mathematical theory methods of heat conduction in practice are well known. Also they are significantly exacerbated if the boundaries of the system under study are movable, even in the simplest case, when the law of motion is known.The main goal of the conducted research is to have an analytically closed-form problem solution for finding the orthotropic half-space temperature field, a boundary of which has thermally thin coating exposed to extremely concentrated stationary external heat flux and uniformly moves parallel to itself.The assumption that the covering of the boundary is thermally thin, allowed to realize the idea of \\concentrated capacity", that is to accept the hypothesis that the mean-thickness coating temperature is equal to the temperature of its boundaries. This assumption allowed us to reduce the problem under consideration to a mixed problem for a parabolic equation with a specific boundary condition.The Hankel integral transform of zero order with respect to the radial variable and the Laplace transform with respect to the temporal variable were used to solve the reduced problem. These techniques have allowed us to submit the required solution as an iterated integral.

  9. In-situ investigation of thermal instabilities and solid state dewetting in polycrystalline platinum thin films via confocal laser microscopy

    Science.gov (United States)

    Jahangir, S.; Cheng, Xuan; Huang, H. H.; Ihlefeld, J.; Nagarajan, V.

    2014-10-01

    Solid state dewetting and the subsequent morphological changes for platinum thin films grown on zinc oxide (ZnO) buffered (001) silicon substrates (Pt/ZnO/SiO2/(001)Si system) is investigated under vacuum conditions via a custom-designed confocal laser microscope coupled with a laser heating system. Live imaging of thin film dewetting under a range of heating and quenching vacuum ambients reveals events including hillock formation, hole formation, and hole growth that lead to formation of a network of Pt ligaments, break up of Pt ligaments to individual islands and subsequent Pt islands shape reformation, in chronological fashion. These findings are corroborated by ex-situ materials characterization and quantitative electron microscopy analysis. A secondary hole formation via blistering before film rupture is revealed to be the critical stage, after which a rapid dewetting catastrophe occurs. This process is instantaneous and cannot be captured by ex-situ methods. Finally, an intermetallic phase forms at 900 °C and alters the morphology of Pt islands, suggesting a practical limit to the thermal environments that may be used for these platinized silicon wafers in vacuum conditions.

  10. In-situ investigation of thermal instabilities and solid state dewetting in polycrystalline platinum thin films via confocal laser microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Jahangir, S.; Cheng, Xuan; Huang, H. H.; Nagarajan, V. [School of Materials Science and Engineering, University of New South Wales, Sydney 2052 (Australia); Ihlefeld, J. [Electronic, Optical, and Nanomaterials Department, Sandia National Laboratories, Albuquerque, New Mexico 87185 (United States)

    2014-10-28

    Solid state dewetting and the subsequent morphological changes for platinum thin films grown on zinc oxide (ZnO) buffered (001) silicon substrates (Pt/ZnO/SiO{sub 2}/(001)Si system) is investigated under vacuum conditions via a custom-designed confocal laser microscope coupled with a laser heating system. Live imaging of thin film dewetting under a range of heating and quenching vacuum ambients reveals events including hillock formation, hole formation, and hole growth that lead to formation of a network of Pt ligaments, break up of Pt ligaments to individual islands and subsequent Pt islands shape reformation, in chronological fashion. These findings are corroborated by ex-situ materials characterization and quantitative electron microscopy analysis. A secondary hole formation via blistering before film rupture is revealed to be the critical stage, after which a rapid dewetting catastrophe occurs. This process is instantaneous and cannot be captured by ex-situ methods. Finally, an intermetallic phase forms at 900 °C and alters the morphology of Pt islands, suggesting a practical limit to the thermal environments that may be used for these platinized silicon wafers in vacuum conditions.

  11. Synthesis and kinetics studies of poly(styrene-b-vinylmethylsiloxane) and its thin film ordering by thermal and solvent annealing

    Science.gov (United States)

    Chatterjee, Sourav; Uddin, Md Fakar; Lwoya, Baraka; Albert, Julie N. L.

    Nano-structured thin film materials are important materials that find uses in templating and membrane applications. Block copolymers (BCP) have gained considerable attention for next-generation lithographic masks due to their self-assemble into morphologies with periodic sub 20 nm feature sizes with high regularity and reproducibility. A novel synthetic block copolymer of poly(styrene-b-vinylmethylsiloxane) (PS-b-PVMS) was synthesized. Like poly(styrene-b-dimethylsiloxane), this polymer has a high Flory Huggins interaction parameter between blocks to minimize feature size. Furthermore, incorporation of the vinyl side group provides an opportunity for post-polymerization chemical modification to manipulate the interaction parameter or impart functionality for various applications. Synthesis and kinetic studies of PS-b-PVMS as well as PS and PVMS homopolymers will be presented. All polymers are well characterized by proton NMR and GPC. As proof of concept, we show that block copolymers having different block fractions self-assemble into the expected nanostructures (lamellae, cylinders, spheres). Thin film studies also will be presented showing how the ordering of PS-b-PVMS is affected by different solvent and thermal annealing conditions.

  12. Investigation of thermal annealing effects on microstructural and optical properties of HfO{sub 2} thin films

    Energy Technology Data Exchange (ETDEWEB)

    Modreanu, M. [Tyndall National Institute, Cork (Ireland)]. E-mail: mircea.modreanu@tyndall.ie; Sancho-Parramon, J. [Tyndall National Institute, Cork (Ireland); Durand, O. [Thales Research and Technology France, Route Departementale 128, F-91767 Palaiseau Cedex (France); Servet, B. [Thales Research and Technology France, Route Departementale 128, F-91767 Palaiseau Cedex (France); Stchakovsky, M. [Horiba Jobin-Yvon, Thin Film Division, Chilly-Mazarin (France); Eypert, C. [Horiba Jobin-Yvon, Thin Film Division, Chilly-Mazarin (France); Naudin, C. [HORIBA Jobin-Yvon Raman Division, Villeneuve d' Ascq (France); Knowles, A. [HORIBA Jobin-Yvon Ltd., Raman Division, Middlesex (United Kingdom); Bridou, F. [Laboratoire Charles Fabry de l' Institut d' Optique, CNRS, Unite mixte de Recherche 85801, 91403 Orsay Cedex (France); Ravet, M.-F. [Laboratoire Charles Fabry de l' Institut d' Optique, CNRS, Unite mixte de Recherche 85801, 91403 Orsay Cedex (France)

    2006-10-31

    In the present paper, we investigate the effect of thermal annealing on optical and microstructural properties of HfO{sub 2} thin films (from 20 to 190 nm) obtained by plasma ion assisted deposition (PIAD). After deposition, the HfO{sub 2} films were annealed in N{sub 2} ambient for 3 h at 300, 350, 450, 500 and 750 deg. C. Several characterisation techniques including X-ray reflectometry (XRR), X-ray diffraction (XRD), spectroscopic ellipsometry (SE), UV Raman and FTIR were used for the physical characterisation of the as-deposited and annealed HfO{sub 2} thin films. The results indicate that as-deposited PIAD HfO{sub 2} films are mainly amorphous and a transition to a crystalline phase occurs at a temperature higher than 450 deg. C depending on the layer thickness. The crystalline grains consist of cubic and monoclinic phases already classified in literature but this work provides the first evidence of amorphous-cubic phase transition at a temperature as low as 500 deg. C. According to SE, XRR and FTIR results, an increase in the interfacial layer thickness can be observed only for high temperature annealing. The SE results show that the amorphous phase of HfO{sub 2} (in 20 nm thick samples) has an optical bandgap of 5.51 eV. Following its transition to a crystalline phase upon annealing at 750 deg. C, the optical bandgap increases to 5.85 eV.

  13. Line Heat-Source Guarded Hot Plate

    Data.gov (United States)

    Federal Laboratory Consortium — Description:The 1-meter guarded hot-plate apparatus measures thermal conductivity of building insulation. This facility provides for absolute measurement of thermal...

  14. A unified analysis of kinetic models for the problem of thermal creep based on the boundary conditions of Cercignani-Lampis for heterogeneous plates

    Energy Technology Data Exchange (ETDEWEB)

    Rosa, Cinara Ewerling da, E-mail: cinara@pb.ifarroupilha.edu.br [Universidade Federal do Rio Grande do Sul (IFF/UFRS), Porto Alegre, RS (Brazil); Instituto Federal Farroupilha, Panambi, RS (Brazil); Knackfuss, Rosenei Felippe, E-mail: knackfuss@smail.ufsm.br [Universidade Federal de Santa Maria (UFSM), Santa Maria, RS (Brazil)

    2013-07-01

    In this work is presented a series of numerical results and graphical comparisons of the physical quantities of interest such as: the velocity profile and the heat on profile. This formulation is developed for the problem of Thermal Creep, where the gas is moving between two parallel plates with different chemical constitutions (heterogeneous plates) due to a temperature gradient. The flow of a rarefied gas, is investigated with special attention to the gas-surface interaction, modeled by the Cercignani-Lampis kernel, that unlike Maxwell's scattering kernel, is defined in terms of two accommodation coefficients (normal and tangential) to represent the physical properties of the gas. The kinetic theory for rarefied gas dynamics, derived from the linearized Boltzmann equation, is developed in an unified approach, to the BGK model, S model, GJ model and MRS model. In the search for solutions to solve the problem of Thermal Creep with kernel of the Cercignani-Lampis, we used a analytical version of the discrete ordinates method (ADO) based on an arbitrary quadrature scheme, under which is determined a problem of eigenvalues and their respective separation constants. Numerical results are developed by the computer program FORTRAN. (author)

  15. Numerical investigation of MHD free convection flow of a non-Newtonian fluid past an impulsively started vertical plate in the presence of thermal diffusion and radiation absorption

    Directory of Open Access Journals (Sweden)

    M. Umamaheswar

    2016-09-01

    Full Text Available A numerical investigation is carried out on an unsteady MHD free convection flow of a well-known non-Newtonian visco elastic second order Rivlin-Erickson fluid past an impulsively started semi-infinite vertical plate in the presence of homogeneous chemical reaction, thermal radiation, thermal diffusion, radiation absorption and heat absorption with constant mass flux. The presence of viscous dissipation is also considered at the plate under the influence of uniform transverse magnetic field. The flow is governed by a coupled nonlinear system of partial differential equations which are solved numerically by using finite difference method. The effects of various physical parameters on the flow quantities viz. velocity, temperature, concentration, Skin friction, Nusselt number and Sherwood number are studied numerically. The results are discussed with the help of graphs. We observed that the velocity decreases with an increase in magnetic field parameter, Schmidt number, and Prandtl number while it increases with an increase in Grashof number, modified Grashof number, visco-elastic parameter and Soret number. Temperature increases with an increase in radiation absorption parameter, Eckert number and visco-elastic parameter while it decreases with increasing values of radiation parameter, Prandtl number and heat absorption parameter. Concentration increases with increase in Soret number while it decreases with an increase in Schmidt number and chemical reaction parameter.

  16. Thermal oxidation of Ni films for p-type thin-film transistors

    KAUST Repository

    Jiang, Jie

    2013-01-01

    p-Type nanocrystal NiO-based thin-film transistors (TFTs) are fabricated by simply oxidizing thin Ni films at temperatures as low as 400 °C. The highest field-effect mobility in a linear region and the current on-off ratio are found to be 5.2 cm2 V-1 s-1 and 2.2 × 103, respectively. X-ray diffraction, transmission electron microscopy and electrical performances of the TFTs with "top contact" and "bottom contact" channels suggest that the upper parts of the Ni films are clearly oxidized. In contrast, the lower parts in contact with the gate dielectric are partially oxidized to form a quasi-discontinuous Ni layer, which does not fully shield the gate electric field, but still conduct the source and drain current. This simple method for producing p-type TFTs may be promising for the next-generation oxide-based electronic applications. © 2013 the Owner Societies.

  17. Thin cuprous oxide films prepared by thermal oxidation of copper foils with water vapor

    Energy Technology Data Exchange (ETDEWEB)

    Liang Jianbo, E-mail: liangjienbo1980@yahoo.co.jp [Department of Frontier Materials,Nagoya Institute of Technology, Nagoya 4668555 (Japan); Kishi, Naoki; Soga, Tetsuo [Department of Frontier Materials,Nagoya Institute of Technology, Nagoya 4668555 (Japan); Jimbo, Takashi [Research Center for Nano-Device and System, Nagoya Institute of Technology, Nagoya 4668555 (Japan); Ahmed, Mohsin [Department of Frontier Materials,Nagoya Institute of Technology, Nagoya 4668555 (Japan)

    2012-01-31

    We present an improved preparation method for the growth of high quality crystals of cuprous oxide films grown by thermal oxidation of cupper foils with water vapor. This method proved to be good for preparing cuprous oxide films with high purity and large grain size. X-ray diffraction studies revealed the formation of Cu{sub 2}O films with preferred (111) orientation. The cuprous oxide diodes fabricated by the above technique have been studied using current-voltage method.

  18. Electrochemical detection of the thermally induced phase transition of a thin stimuli-responsive polymer film.

    Science.gov (United States)

    Fandrich, Artur; Buller, Jens; Wischerhoff, Erik; Laschewsky, André; Lisdat, Fred

    2012-06-04

    Quick and easy: An efficient approach for a direct observation of a thermally induced phase transition of a responsive polymer film on gold surfaces is described. Voltammetric measurements show that the peak current and the peak separation for a small redox couple are particularly sensitive to the conformational change of the polymer film and allow its phase transition detection. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  19. Comparison of Ultrasonic Welding and Thermal Bonding for the Integration of Thin Film Metal Electrodes in Injection Molded Polymeric Lab-on-Chip Systems for Electrochemistry

    DEFF Research Database (Denmark)

    Matteucci, Marco; Heiskanen, Arto; Zor, Kinga

    2016-01-01

    We compare ultrasonic welding (UW) and thermal bonding (TB) for the integration of embedded thin-film gold electrodes for electrochemical applications in injection molded (IM) microfluidic chips. The UW bonded chips showed a significantly superior electrochemical performance compared to the ones...

  20. Thermophoresis and thermal radiation with heat and mass transfer in a magnetohydrodynamic thin-film second-grade fluid of variable properties past a stretching sheet

    Science.gov (United States)

    Khan, Noor Saeed; Gul, Taza; Islam, Saeed; Khan, Waris

    2017-01-01

    The influences of thermophoresis and thermal radiation of a magnetohydrodynamic two-dimensional thin-film second-grade fluid with heat and mass transfer flow in the presence of viscous dissipation past a stretching sheet are analyzed. The main focus of the study is to discuss the significant roll of the fluid variable properties like thermal conductivity and viscosity under the variation of the thin film. The thermal conductivity varies directly as a linear function of temperature showing the property that expresses the ability of a material to transfer heat, and the viscosity is assumed to vary inversely as a linear function of temperature showing that viscous forces become weak at increasing temperature. Thermophoresis occurs to discuss the mass deposition at the surface of the stretching sheet while thermal radiation occurs, especially, at high temperature. The basic governing equations for the velocity, temperature and concentration of the fluid flow have been transformed to high nonlinear coupled differential equations with physical conditions by invoking suitable similarity transformations. The solution of the problem has been obtained by using HAM (Homotopy Analysis Method). The heat and mass transfer flow behaviors are affected significantly by the thin film. The physical influences of thin film parameter and all other parameters have been studied graphically and illustrated. The residual graphs and residual error table elucidate the authentication of the present work.

  1. High thermal robustness of molecularly thin perovskite nanosheets and implications for superior dielectric properties.

    Science.gov (United States)

    Li, Bao-Wen; Osada, Minoru; Ebina, Yasuo; Akatsuka, Kosho; Fukuda, Katsutoshi; Sasaki, Takayoshi

    2014-06-24

    A systematic study has been conducted to examine the thermal stability of layer-by-layer assembled films of perovskite-type nanosheets, (Ca2Nb3O10(-))n (n = 1-10), which exhibit superior dielectric and insulating properties. In-plane and out-of-plane X-ray diffraction data as well as observations by atomic force microscopy and transmission electron microscopy indicated the high thermal robustness of the nanosheet films. In a monolayer film with an extremely small thickness of ∼2 nm, the nanosheet was stable up to 800 °C, the temperature above which segregation into CaNb2O6 and Ca2Nb2O7 began. The critical temperature moderately decreased as the film thickness, or the number of nanosheet layers, increased, and reached 700 °C for seven- and 10-layer films, which is comparable to the phase transformation temperature for a bulk phase of the protonic layered oxide of HCa2Nb3O10·1.5H2O as a precursor of the nanosheet. This thermal stabilization of perovskite-type nanosheets should be associated with restricted nucleation and crystal growth peculiar to such ultrathin 2D bound systems. The stable high-k dielectric response (εr = 210) and highly insulating nature (J niobate nanosheets in terms of structure and dielectric properties, which suggests promising potential for future high-k devices operable over a wide temperature range.

  2. Rapid thermal annealing of sputter-deposited ZnO:Al films for microcrystalline Si thin-film solar cells

    Directory of Open Access Journals (Sweden)

    Hanajiri T.

    2012-06-01

    Full Text Available Rapid thermal annealing of sputter-deposited ZnO and Al-doped ZnO (AZO films with and without an amorphous silicon (a-Si capping layer was investigated using a radio-frequency (rf argon thermal plasma jet of argon at atmospheric pressure. The resistivity of bare ZnO films on glass decreased from 108 to 104–105 Ω cm at maximum surface temperatures Tmaxs above 650 °C, whereas the resistivity increased from 10-4 to 10-3–10-2Ω cm for bare AZO films. On the other hand, the resistivity of AZO films with a 30-nm-thick a-Si capping layer remained below 10-4Ω cm, even after TPJ annealing at a Tmax of 825 °C. The film crystallization of both AZO and a-Si layers was promoted without the formation of an intermixing layer. Additionally, the crystallization of phosphorous- and boron-doped a-Si layers at the sample surface was promoted, compared to that of intrinsic a-Si under the identical plasma annealing conditions. The TPJ annealing of n+-a-Si/textured AZO was applied for single junction n-i-p microcrystalline Si thin-film solar cells.

  3. Thermal and hydraulic performance of compact brazed plate heat exchangers operating as evaporators in domestic heat pumps

    OpenAIRE

    Claesson, Joachim

    2005-01-01

    This thesis investigates the performance of compact brazed plate heat exchangers (CBE) operating as evaporator in heat pump applications. The thesis, and the performances investigated, has been divided into three main sections; One zone evaporator performance; Two zone evaporator performance; and finally Local performance. The 'One zone evaporator performance' section considers the evaporator as one "black box". It was found that "approaching terminal temperatures" were obtained as low overal...

  4. GALVANIC MAGNETIC PROPERTIES OF BISMUTH THIN FILMS DOPED WITH TELLURIUM MADE BY THERMAL VACUUM EVAPORATION

    Directory of Open Access Journals (Sweden)

    V. A. Komarov

    2013-01-01

    Full Text Available The influence of n-type impurity of tellurium (concentration range from 0.005 atomic % Te to 0.15 atomic % Te on galvanic magnetic properties (resistivity, magnetic resistance and Hall constant of Bi thin films with various thicknesses was studied. The properties were measured in temperature range from 77 to 300 K. It was established that the classical size effect in the films is significant and decreases with higher concentration of Te impurity. The analysis of experimental results was carried out in approximation of the law of Jones-Schoenberg dispersion for Bi films doped with tellurium. Calculation of concentration and mobility of charge carriers in the studied films was made.

  5. Thermal activation of nitrogen acceptors in ZnO thin films grown by MOCVD

    Energy Technology Data Exchange (ETDEWEB)

    Dangbegnon, J.K.; Talla, K.; Botha, J.R. [Department of Physics, Nelson Mandela Metropolitan University, P.O. Box 77000, Port Elizabeth (South Africa)

    2010-06-15

    Nitrogen doping in ZnO is inhibited by spontaneous formation of compensating defects. Perfect control of the nitrogen doping concentration is required, since a high concentration of nitrogen could induce the formation of donor defects involving nitrogen. In this work, the effect of post-growth annealing in oxygen ambient on ZnO thin films grown by Metalorganic Chemical Vapor Deposition, using NO as both oxidant and nitrogen dopant, is studied. After annealing at 700 C and above, low-temperature photoluminescence shows the appearance of a transition at {proportional_to}3.23 eV which is interpreted as pair emission involving a nitrogen acceptor. A second transition at {proportional_to}3.15 eV is also discussed. This work suggests annealing as a potential means for p-type doping using nitrogen (copyright 2010 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  6. Rapid thermal annealing of FePt and FePt/Cu thin films

    Energy Technology Data Exchange (ETDEWEB)

    Brombacher, Christoph

    2011-01-10

    Chemically ordered FePt is one of the most promising materials to reach the ultimate limitations in storage density of future magnetic recording devices due to its high uniaxial magnetocrystalline anisotropy and a corrosion resistance superior to rare-earth based magnets. In this study, FePt and FePt/Cu bilayers have been sputter deposited at room temperature onto thermally oxidized silicon wafers, glass substrates and self-assembled arrays of spherical SiO{sub 2} particles with diameters down to 10 nm. Millisecond flash lamp annealing, as well as conventional rapid thermal annealing was employed to induce the phase transformation from the chemically disordered A1 phase into the chemically ordered L1{sub 0} phase. The influence of the annealing temperature, annealing time and the film thickness on the ordering transformation and (001) texture evolution of FePt films with near equiatomic composition was studied. Whereas flash lamp annealed FePt films exhibit a polycrystalline morphology with high chemical L1{sub 0} order, rapid thermal annealing can lead to the formation of chemically ordered FePt films with (001) texture on amorphous SiO{sub 2}/Si substrates. The resultant high perpendicular magnetic anisotropy and large coercivities up to 40 kOe are demonstrated. Simultaneously to the ordering transformation, rapid thermal annealing to temperatures exceeding 600 C leads to a break up of the continuous FePt film into separated islands. This dewetting behavior was utilized to create regular arrays of FePt nanostructures on SiO{sub 2} particle templates with periods down to 50 nm. The addition of Cu improves the (001) texture formation and chemical ordering for annealing temperatures T{sub a} {<=}600 C. In addition, the magnetic anisotropy and the coercivity of the ternary FePtCu alloy can be effectively tailored by adjusting the Cu content. The prospects of FePtCu based exchange spring media, as well as the magnetic properties of FePtCu nanostructures fabricated

  7. Electro-thermal control of aluminum-doped zinc oxide/vanadium dioxide multilayered thin films for smart-device applications.

    Science.gov (United States)

    Skuza, J R; Scott, D W; Mundle, R M; Pradhan, A K

    2016-02-17

    We demonstrate the electro-thermal control of aluminum-doped zinc oxide (Al:ZnO) /vanadium dioxide (VO2) multilayered thin films, where the application of a small electric field enables precise control of the applied heat to the VO2 thin film to induce its semiconductor-metal transition (SMT). The transparent conducting oxide nature of the top Al:ZnO film can be tuned to facilitate the fine control of the SMT of the VO2 thin film and its associated properties. In addition, the Al:ZnO film provides a capping layer to the VO2 thin film, which inhibits oxidation to a more energetically favorable and stable V2O5 phase. It also decreases the SMT of the VO2 thin film by approximately 5-10 °C because of an additional stress induced on the VO2 thin film and/or an alteration of the oxygen vacancy concentration in the VO2 thin film. These results have significant impacts on technological applications for both passive and active devices by exploiting this near-room-temperature SMT.

  8. Effect of Substrate Temperature on the Thermoelectric Properties of the Sb2Te3 Thin Films Deposition by Using Thermal Evaporation Method

    Directory of Open Access Journals (Sweden)

    Jyun-Min Lin

    2015-01-01

    Full Text Available The antimony-telluride (Sb2Te3 thermoelectric thin films were prepared on SiO2/Si substrates by thermal evaporation method. The substrate temperature that ranged from room temperature to 150°C was adopted to deposit the Sb2Te3 thin films. The effects of substrate temperature on the microstructures and thermoelectric properties of the Sb2Te3 thin films were investigated. The crystal structure and surface morphology of the Sb2Te3 thin films were characterized by X-ray diffraction analyses and field emission scanning electron microscope observation. The RT-deposited Sb2Te3 thin films showed the amorphous phase. Te and Sb2Te3 phases were coexisted in the Sb2Te3-based thin films as the substrate temperature was higher than room temperature. The average grain sizes of the Sb2Te3-based thin films were 39 nm, 45 nm, 62 nm, 84 nm, and 108 nm, as the substrate temperatures were 50°C, 75°C, 100°C, 125°C, and 150°C, respectively. The Seebeck coefficients, electrical conductivity, and power factor were measured at room temperature; we had found that they were critically dependent on the substrate temperature.

  9. Enhanced bolometric properties of TiO2-x thin films by thermal annealing

    Science.gov (United States)

    Ashok Kumar Reddy, Y.; Shin, Young Bong; Kang, In-Ku; Lee, Hee Chul; Sreedhara Reddy, P.

    2015-07-01

    The effect of thermal annealing on the bolometric properties of TiO2-x films was investigated. The test-patterned TiO2-x samples were annealed at 300 °C temperature in order to enhance their structural and electrical properties for effective infrared image sensor device applications. The crystallinity was changed from amorphous to rutile/anatase in annealed TiO2-x films. Compared to the as-deposited samples, a decrement of the band gap and a decrease of the electrical resistivity were perceived in annealed samples. We found that the annealed samples show linear current-voltage (I-V) characteristic performance, which implies that ohmic contact was well formed at the interface between the TiO2-x and the Ti electrode. Moreover, the annealed TiO2-x sample had a significantly low 1/f noise parameter (1.21 × 10-13) with a high bolometric parameter (β) value compared to those of the as-deposited samples. As a result, the thermal annealing process can be used to prepare TiO2-x film for a high-performance bolometric device.

  10. Time-Resolved Magneto-Optical Kerr Effect of Magnetic Thin Films for Ultrafast Thermal Characterization.

    Science.gov (United States)

    Chen, Jun-Yang; Zhu, Jie; Zhang, Delin; Lattery, Dustin M; Li, Mo; Wang, Jian-Ping; Wang, Xiaojia

    2016-07-07

    Thermomagnetic and magneto-optical effects are two fundamental but unique phenomena existing in magnetic materials. In this work, we demonstrate ultrafast time-resolved magneto-optical Kerr effect (TR-MOKE) as an advanced thermal characterization technique by studying the original factors of the MOKE signal from four magnetic transducers, including TbFe, GdFeCo, Co/Pd, and CoFe/Pt. A figure of merit is proposed to evaluate the performance of the transducer layers, corresponding to the degree of the signal-to-noise ratio in TR-MOKE measurements. We observe improved figure of merit for rare-earth transition-metal-based TbFe and GdFeCo transducers and attribute this improvement to their relatively larger temperature-dependent magnetization and the Kerr rotation angle at the saturated magnetization state. Furthermore, an optimal thickness of TbFe is found to be ∼18.5 nm to give the best performance. Our findings will facilitate the nanoscale thermal characterization and the device design where the thermo-magneto-optical coupling plays an important role.

  11. Thermal fluctuations and effective bending stiffness of elastic thin sheets and graphene: A nonlinear analysis

    Science.gov (United States)

    Ahmadpoor, Fatemeh; Wang, Peng; Huang, Rui; Sharma, Pradeep

    2017-10-01

    The study of statistical mechanics of thermal fluctuations of graphene-the prototypical two-dimensional material-is rendered rather complicated due to the necessity of accounting for geometric deformation nonlinearity. Unlike fluid membranes such as lipid bilayers, coupling of stretching and flexural modes in solid membranes like graphene leads to a highly anharmonic elastic Hamiltonian. Existing treatments draw heavily on analogies in the high-energy physics literature and are hard to extend or modify in the typical contexts that permeate materials, mechanics and some of the condensed matter physics literature. In this study, using a variational perturbation method, we present a ;mechanics-oriented; treatment of the thermal fluctuations of elastic sheets such as graphene and evaluate their effect on the effective bending stiffness at finite temperatures. In particular, we explore the size, pre-strain and temperature dependency of the out-of-plane fluctuations, and demonstrate how an elastic sheet becomes effectively stiffer at larger sizes. Our derivations provide a transparent approach that can be extended to include multi-field couplings and anisotropy for other 2D materials. To reconcile our analytical results with atomistic considerations, we also perform molecular dynamics simulations on graphene and contrast the obtained results and physical insights with those in the literature.

  12. Thermal resistant efficiency of Nb-doped TiO2 thin film based glass window

    Directory of Open Access Journals (Sweden)

    Luu Manh Quynh

    2017-09-01

    Full Text Available The proportional relationship between the infrared (IR transmittance of a transparent material and its IR-induced heat transfer can be explained via a simple model. An agreement between the theory and the experimental work was examined by measuring the temperature rising inside a heat-insulated box with glass windows under IR irradiation, where the material of the glass windows was modified from corning glass (CG to 9 at% Nb-doped TiO2 (TNO fabricated by sputtering deposition. The fabricated TNO thin film was mostly transparent in a visible region and had a low transparency in the IR region, which, in turn, produced the self-cooling effect inside the insulated box. In comparison to the window glass made by CG, the temperature increase inside the box would be 24% less if the window was made by CG coated by TNO (TNO on CG. This suggests the possibility of manufacturing products with desirable features in the energy-cut cooling. The energy-cut was found to decline proportionally to the decrease of the glass window area.

  13. Anisotropic properties of high-temperature polyimide thin films: Dielectric and thermal-expansion behaviors

    Science.gov (United States)

    Ree, M.; Chen, K.-J.; Kirby, D. P.; Katzenellenbogen, N.; Grischkowsky, D.

    1992-09-01

    Multilayer poly(p-phenylene biphenyltetracarboximide) (BPDA-PDA) polyimide films of 172 μm total thickness (11.4 μm per layer) were prepared from the poly(amic acid) precursor solution through repetition of a spin-coat/softbake/cure process. Wide-angle x-ray diffraction results indicate that the polyimide molecules in the multilayer films are highly ordered along the chain axes as well as in the lateral direction and furthermore are highly oriented in the film plane as observed in a single-layer film of 11.4 μm thickness. The multilayer films showed the same dynamic mechanical properties and glass transition behavior (Tg = 330 °C) as a single-layer film. For the multilayer films both the in-plane dielectric constant (ɛ'XY) and out-of-plane thermal-expansion coefficient (αZ) were measured using time-domain spectroscopy and conventional thermal mechanical analysis, respectively. The ɛ'XY at room temperature was 3.69 (±0.08) over a frequency range of 0.35-2.50 THz. A similar ɛ'XY is predicted at frequencies of ≤0.35 THz. In contrast to the ɛ'XY, a relatively lower out-of-plane dielectric constant (ɛ'Z) was observed: ɛ'Z = 2.96-3.03 (±0.02) at 1 MHz, depending on moisture content in the film. The dielectric loss ɛ`Z at 1 MHz was 0.011-0.014 (±0.001), depending on moisture content. The measured αZ was 74 ppm/°C over the temperature range of 25-150 °C, which was much higher than αXY = 2.6-5 ppm/°C. Consequently, large anisotropic ɛ' and α have been observed in the in plane and out of plane of the thermally imidized BPDA-PDA films. The anisotropic ɛ' and α were caused by high in-plane orientation of the polyimide molecules highly ordered along the chain axes in the films.

  14. Room temperature and thermal decomposition of magnesium hydride/deuteride thin films

    Energy Technology Data Exchange (ETDEWEB)

    Ares, J.R.; Leardini, F.; Bodega, J.; Macia, M.D.; Diaz-Chao, P.; Ferrer, I.J.; Fernandez, J.F.; Sanchez, C. [Universidad Autonoma de Madrid (Spain). Lab. de Materiales de Interes en Energias Renovables

    2010-07-01

    Magnesium hydride (MgH{sub 2}) can be considered an interesting material to store hydrogen as long as two main drawbacks were solved: (i) its high stability and (ii) slow (de)hydriding kinetics. In that context, magnesium hydride films are an excellent model system to investigate the influence of structure, morphology and dimensionality on kinetic and thermodynamic properties. In the present work, we show that desorption mechanism of Pd-capped MgH{sub 2} at room temperature is controlled by a bidimensional interphase mechanism and a similar rate step limiting mechanism is observed during thermal decomposition of MgH{sub 2}. This mechanism is different to that occurring in bulk MgH{sub 2} (nucleation and growth) and obtained activation energies are lower than those reported in bulk MgH{sub 2}. We also investigated the Pd-capping properties upon H-absorption/desorption by means of RBS and isotope experiments. (orig.)

  15. Optical and thermal characterizations of AgSbTe chalcogenide-based thin films

    Science.gov (United States)

    Sharma, Y. D.; Bhatnagar, P.; Suhara, T.

    2005-09-01

    A systematic investigation of the Ag x -Sb 2 (1-x) -Te 3 (1-x) (x=0.16, 0.18 and 0.20) is reported. The alloy of Ag-Sb-Te glass system, obtained by rapid quenching technique has been characterized by calorimetric measurements and differential thermal analysis (DTA) for different heating rates. The optical properties of the material were studied using UV spectrophotometer. The optical band gap (E o) was estimated for these samples by measuring absorption coefficient as a function of wavelength of light in the range 300 -900 nm. The films of the different compositions of Ag were studied for both the cases of before and after annealing. The present study is an attempt to understand the effect of alloying Ag into amorphous Te chalcogenide glasses.

  16. Fly ash based geopolymer thin coatings on metal substrates and its thermal evaluation.

    Science.gov (United States)

    Temuujin, Jadambaa; Minjigmaa, Amgalan; Rickard, William; Lee, Melissa; Williams, Iestyn; van Riessen, Arie

    2010-08-15

    Class F fly ash based Na-geopolymer formulations have been applied as fire resistant coatings on steel. The main variables for the coating formulations were Si: Al molar and water: cement weight ratios. We have determined that the adhesive strength of the coatings strongly depend on geopolymer composition. The ease with which geopolymer can be applied onto metal surfaces and the resultant thickness depend on the water content of the formulation. Adhesive strengths of greater than 3.5 MPa have been achieved on mild steel surfaces for compositions with Si:Al of 3.5. Microstructure evolution and thermal properties of the optimised coating formulations show that they have very promising fire resistant characteristics. Copyright 2010 Elsevier B.V. All rights reserved.

  17. Metamorphosis of strain/stress on optical band gap energy of ZAO thin films via manipulation of thermal annealing process

    Energy Technology Data Exchange (ETDEWEB)

    Malek, M.F., E-mail: firz_solarzelle@yahoo.com [NANO-ElecTronic Centre (NET), Faculty of Electrical Engineering, Universiti Teknologi MARA (UiTM), 40450 Shah Alam, Selangor (Malaysia); NANO-SciTech Centre (NST), Institute of Science (IOS), Universiti Teknologi MARA UiTM, 40450 Shah Alam, Selangor (Malaysia); Mamat, M.H. [NANO-ElecTronic Centre (NET), Faculty of Electrical Engineering, Universiti Teknologi MARA (UiTM), 40450 Shah Alam, Selangor (Malaysia); Musa, M.Z. [NANO-ElecTronic Centre (NET), Faculty of Electrical Engineering, Universiti Teknologi MARA (UiTM), 40450 Shah Alam, Selangor (Malaysia); Faculty of Electrical Engineering, Universiti Teknologi MARA (UiTM) Pulau Pinang, Jalan Permatang Pauh, 13500 Permatang Pauh, Pulau Pinang (Malaysia); Soga, T. [Department of Frontier Materials, Nagoya Institute of Technology (NITech), Nagoya 466-8555 (Japan); Rahman, S.A. [Low Dimensional Materials Research Centre (LDMRC), Department of Physics, Faculty of Science, Universiti Malaya (UM), 50603 Kuala Lumpur (Malaysia); Alrokayan, Salman A.H.; Khan, Haseeb A. [Department of Biochemistry, College of Science, King Saud University (KSU), Riyadh 11451 (Saudi Arabia); Rusop, M. [NANO-ElecTronic Centre (NET), Faculty of Electrical Engineering, Universiti Teknologi MARA (UiTM), 40450 Shah Alam, Selangor (Malaysia); NANO-SciTech Centre (NST), Institute of Science (IOS), Universiti Teknologi MARA UiTM, 40450 Shah Alam, Selangor (Malaysia)

    2015-04-15

    We report on the growth of Al-doped ZnO (ZAO) thin films prepared by the sol–gel technique associated with dip-coating onto Corning 7740 glass substrates. The influence of varying thermal annealing (T{sub a}) temperature on crystallisation behaviour, optical and electrical properties of ZAO films has been systematically investigated. All films are polycrystalline with a hexagonal wurtzite structure with a preferential orientation according to the direction 〈0 0 2〉. The metamorphosis of strain/stress effects in ZAO thin films has been investigated using X-ray diffraction. The as growth films have a large compressive stress of 0.55 GPa, which relaxed to 0.25 GPa as the T{sub a} was increased to 500 °C. Optical parameters such as optical transmittance, absorption coefficient, refractive index and optical band gap energy have been studied and discussed with respect to T{sub a}. All films exhibit a transmittance above 80–90% along the visible–NIR range up to 1500 nm and a sharp absorption onset below 400 nm corresponding to the fundamental absorption edge of ZnO. Experimental results show that the tensile stress in the films reveals an incline pattern with the optical band gap energy, while the compressive stress shows opposite relation. - Highlights: • Minimum stress of highly c-axis oriented ZAO was grown at suitable T{sub a} temperature. • The ZAO crystal orientation was influenced by strain/stress of the film. • Minimum stress/strain of ZAO film leads to lower defects. • Bandgap and defects were closely intertwined with strain/stress. • We report additional optical and electrical properties based on T{sub a} temperature.

  18. A thermal design method for the performance optimization of multi-stream plate-fin heat exchangers

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Zhe; Li, Yanzhong [Xi’an Jiaotong University, Xi’an (China); Sunden, Bengt [Lund University, Lund (Sweden); Han, Fenghui [Dalian Maritime University, Dalian (China)

    2017-06-15

    An optimization design method based on field synergy principle is developed for Multi-stream plate-fin heat exchangers (MPHEs) with a segmented differential model. The heat exchanger is divided into a number of sub-exchangers along the main stream, and each sub-exchanger consists of N passages along the height of the exchanger. Compared with the traditional heat exchanger design, this method allows temperature and pressure fields to be obtained via coupling calculation with consideration of variable physical properties and the axial heat loss of the heat exchanger. Finally, the heat exchanger is optimally designed using a temperature-difference uniformity optimization factor based on field synergy principle. This design model can provide an accurate temperature field and pressure field, because the stream properties are determined by the mean temperature and pressure of each local sub-exchanger. Optimum results indicate that the temperature distribution on the cross section of the heat exchanger is relatively uniform and that the temperature difference of heat transfer for each stream is always a small value. These characteristics prove the feasibility and effectiveness of this design model. In this paper, a case of five stream plate-fin heat exchangers for an ethylene plant is designed under a practical cold box operating condition with the proposed model, the structure and heat transfer of which are optimally determined. The design model and optimization method proposed in this work can provide theoretical and technical support to the optimization design of MPHEs.

  19. Direct synthesis and characterization of optically transparent conformal zinc oxide nanocrystalline thin films by rapid thermal plasma CVD

    Science.gov (United States)

    Pedersen, Joachim D.; Esposito, Heather J.; Teh, Kwok Siong

    2011-10-01

    We report a rapid, self-catalyzed, solid precursor-based thermal plasma chemical vapor deposition process for depositing a conformal, nonporous, and optically transparent nanocrystalline ZnO thin film at 130 Torr (0.17 atm). Pure solid zinc is inductively heated and melted, followed by ionization by thermal induction argon/oxygen plasma to produce conformal, nonporous nanocrystalline ZnO films at a growth rate of up to 50 nm/min on amorphous and crystalline substrates including Si (100), fused quartz, glass, muscovite, c- and a-plane sapphire (Al2O3), gold, titanium, and polyimide. X-ray diffraction indicates the grains of as-deposited ZnO to be highly textured, with the fastest growth occurring along the c-axis. The individual grains are observed to be faceted by (103) planes which are the slowest growth planes. ZnO nanocrystalline films of nominal thicknesses of 200 nm are deposited at substrate temperatures of 330°C and 160°C on metal/ceramic substrates and polymer substrates, respectively. In addition, 20-nm- and 200-nm-thick films are also deposited on quartz substrates for optical characterization. At optical spectra above 375 nm, the measured optical transmittance of a 200-nm-thick ZnO film is greater than 80%, while that of a 20-nm-thick film is close to 100%. For a 200-nm-thick ZnO film with an average grain size of 100 nm, a four-point probe measurement shows electrical conductivity of up to 910 S/m. Annealing of 200-nm-thick ZnO films in 300 sccm pure argon at temperatures ranging from 750°C to 950°C (at homologous temperatures between 0.46 and 0.54) alters the textures and morphologies of the thin film. Based on scanning electron microscope images, higher annealing temperatures appear to restructure the ZnO nanocrystalline films to form nanorods of ZnO due to a combination of grain boundary diffusion and bulk diffusion. PACS: films and coatings, 81.15.-z; nanocrystalline materials, 81.07.Bc; II-VI semiconductors, 81.05.Dz.

  20. Dewetting Kinetics in Polymer Grafted Nanoparticle Thin Films: Impact of Architecture and Viscosity on Thermal Stability

    Science.gov (United States)

    Che, Justin; Jawaid, Ali; Grabowski, Christopher; Yi, Yoon-Jae; Vaia, Richard; AFRL Collaboration

    Rapid formation of ordered monolayers of polymer grafted nanoparticles (PGN) directly onto solid surfaces has spurred interest in using these materials for additive manufacturing of optical devices and energy storage. Herein, we discuss dewetting of polystyrene grafted Au nanoparticles (PS@Au) with an increased thermal (10-25oC) and energetic (5-15 mN/m) stability relative to linear polymer films of comparable thickness. Analogous to star macromolecules, the enhanced stability is related to the conformations of chains in the grafted canopy. Mechanistically, dewetting of PS@Au is similar to linear PS, however, the thickness transition from spinodal to heterogeneous nucleation is at least 5-6x larger. Time resolved optical microscopy during dewetting at 160oC revealed that the zero shear viscosity for linear PS scaled as η0 Mn3. 3 , consistent with reptation of entangled polymers. In contrast, PS@Au showed η0 Mn2. 2 where Mn reflects the molecular weight of the grafted chains. Overall, PS@Au exhibited significantly slower dewetting rates, consistent with a 100x increase in viscosity relative to the linear chain analogues. Quantification of the relationship between PGN architecture (e.g. nanoparticle size, graft density, polymer molecular weight) and dewetting processes is crucial to optimize the order of these assemblies via post-processing, as well as design the PGN canopy to maximize stability for devices.

  1. Rapid Thermal Annealing for Solution Synthesis of Transparent Conducting Aluminum Zinc Oxide Thin Films

    Science.gov (United States)

    Ullah, Sana; De Matteis, Fabio; Davoli, Ivan

    2017-11-01

    Transparent conducting oxide films with optimized dopant molar ratio have been prepared with limited pre- and postdeposition annealing duration of 10 min. Multiple aluminum zinc oxide (AZO) layers were spin-coated on ordinary glass substrates. The predeposition consolidation temperature and dopant molar ratio were optimized for electrical conductivity and optical transparency. Next, a group of films were deposited on Corning glass substrates from precursor solutions with the optimized dopant ratio, followed by postdeposition rapid thermal annealing (RTA) at different temperatures and in controlled environments. The lowest resistivity of 10.1 × 10-3 Ω cm was obtained for films receiving RTA at 600°C for 10 min each in vacuum then in N2-5%H2 environment, while resistivity of 20.3 × 10-3 Ω cm was obtained for films subjected to RTA directly in N2-5%H2. Optical measurements revealed average total transmittance of about 85% in the visible region. A direct allowed transition bandgap was determined based on the absorption edge with a value slightly above 3.0 eV, within the typical range for semiconductors. RTA resulted in desorption of oxygen with enhanced carrier concentration and crystallinity, which increased the carrier mobility with decreased bulk resistivity while maintaining the required optical transparency.

  2. Rapid thermal chemical vapor deposition growth of nanometer-thin SiC on silicon

    Energy Technology Data Exchange (ETDEWEB)

    Steckl, A.J.; Li, J.P. (Univ. of Cincinnati, OH (United States))

    1992-08-28

    Rapid thermal chemical vapor deposition growth of [beta]-SiC ultrathin films on Si (100) was achieved using the carbonization reaction of the silicon substrate with C[sub 3]H[sub 8] gas. Growth rates of 0.5-2 nm s[sup -1] have been achieved at 1100-1300degC using C[sub 3]H[sub 8] flow rates of 7-9 standard cm[sup 3] min[sup -1]. X-ray and electron diffraction indicate single-crystal growth. Therefore nanometer-scale SiC films can be grown by controlling the reaction time to a few seconds. The activation energy at atmospheric pressure is 3.12 eV. The growth rate was found to decrease significantly at higher C[sub 3]H[sub 8] flow rates, leading to films of constant thickness beyond a certain critical reaction time. Using this regime of self-limiting growth, SiC films of 3-5 nm have been grown with relatively little sensitivity to the growth time. (orig.).

  3. Investigation of nanocrystalline thin cobalt films thermally evaporated on Si(100) substrates

    Energy Technology Data Exchange (ETDEWEB)

    Kozłowski, W., E-mail: wkozl@std2.phys.uni.lodz.pl [Department of Solid State Physics, Faculty of Physics and Applied Informatics, University of Łódź, Pomorska 149/153, 90-236 Łódź (Poland); Balcerski, J.; Szmaja, W. [Department of Solid State Physics, Faculty of Physics and Applied Informatics, University of Łódź, Pomorska 149/153, 90-236 Łódź (Poland); Piwoński, I. [Department of Materials Technology and Chemistry, Faculty of Chemistry, University of Łódź, Pomorska 163, 90-236 Łódź (Poland); Batory, D. [Institute of Materials Science and Engineering, Łódź University of Technology, Stefanowskiego 1/15, 90-924 Łódź (Poland); Miękoś, E. [Department of Inorganic and Analytical Chemistry, Faculty of Chemistry, University of Łódź, Tamka 12, 91-403 Łódź (Poland); and others

    2017-03-15

    We have made a quantitative study of the morphological and magnetic domain structures of 100 nm thick nanocrystalline cobalt films thermally evaporated on naturally oxidized Si(100) substrates. The morphological structure is composed of densely packed grains with the average grain size (35.6±0.8) nm. The grains exhibit no geometric alignment and no preferred elongation on the film surface. In the direction perpendicular to the film surface, the grains are aligned in columns. The films crystallize mainly in the hexagonal close-packed phase of cobalt and possess a crystallographic texture with the hexagonal axis perpendicular to the film surface. The magnetic domain structure consists of domains forming a maze stripe pattern with the average domain size (102±6) nm. The domains have their magnetizations oriented almost perpendicularly to the film surface. The domain wall energy, the domain wall thickness and the critical diameter for single-domain particle were determined. - Highlights: • 100 nm thick nanocrystalline cobalt films on Si(100) were studied quantitatively. • The grains are densely packed and possess the average size (35.6±0.8) nm. • The films have a texture with the hexagonal axis perpendicular to the film surface. • The magnetic domains form a maze stripe pattern with the average size (102±6) nm. • The domains are magnetized almost perpendicularly to the film surface.

  4. Thermal stability of MBE-grown epitaxial MoSe2 and WSe2 thin films

    Science.gov (United States)

    Chang, Young Jun; Choy, Byoung Ki; Phark, Soo-Hyon; Kim, Minu

    Layered transition metal dichalcogenides (TMDs) draw much attention, because of its unique optical properties and band structures depending on the layer thicknesses. However, MBE growth of epitaxial films demands information about thermal stability of stoichiometry and related electronic structure for high temperature range. We grow epitaxial MoSe2 and WSe2 ultrathin films by using molecular beam epitaxy (MBE). We characterize stoichiometry of films grown at various growth temperature by using various methods, XPS, EDX, and TOF-MEIS. We further test high temperature stability of electronic structure for those films by utilizing in-situ ellipsometry attached to UHV chamber. We discuss threshold temperatures up to 700~1000oC, at which electronic phases changes from semiconductor to metal due to selenium deficiency. This information can be useful for potential application of TMDs for fabrication of Van der Waals multilayers and related devices. This research was supported by Nano.Material Technology Development Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Science, ICT and Future Planning. (2009-0082580), NRF-2014R1A1A1002868.

  5. Direct extraction of urinary analytes from undeveloped reversed-phase thin layer chromatography plates using a solvent gradient combined with on-line electrospray ionisation ion mobility-mass spectrometry.

    Science.gov (United States)

    Devenport, Neil A; Reynolds, James C; Weston, Daniel J; Wilson, Ian D; Creaser, Colin S

    2012-08-07

    The direct extraction of urinary analytes deposited on reversed-phase thin-layer chromatography (RP-TLC) plates is demonstrated using a solvent gradient extraction procedure without prior chromatographic development. The surface sample probe TLC-MS interface used for the gradient extraction is compared to direct loop injection into the electrospray ion source for biofluid profiling. The gradient elution is shown to enhance ion intensities, as urinary salts are eluted in aqueous formic acid in the early part of the gradient reducing ion suppression. The retention of urinary components on the C18 RP-TLC plate was confirmed by monitoring analyte responses with, and without, an aqueous wash phase prior to the solvent gradient extraction. The use of gradient elution allows fractionation of the complex biological matrix as a result of differential retention of urine components on the undeveloped RP-TLC plate. The direct gradient analysis of TLC plates has also been combined with ion mobility-mass spectrometry to further resolve the complex urinary profile and identify co-eluting compounds.

  6. Photoacoustic elastic bending in thin film—Substrate system

    Energy Technology Data Exchange (ETDEWEB)

    Todorović, D. M., E-mail: dmtodor@imsi.bg.ac.rs [Institute for Multidisciplinary Research, University of Belgrade, P.O. Box 33, 11030 Belgrade (Serbia); Rabasović, M. D.; Markushev, D. D. [Institute of Physics, University of Belgrade, Pregrevica 118, 11080 Belgrade-Zemun (Serbia)

    2013-12-07

    Theoretical model for optically excited two-layer elastic plate, which includes plasmaelastic, thermoelastic, and thermodiffusion mechanisms, is given in order to study the dependence of the photoacoustic (PA) elastic bending signal on the optical, thermal, and elastic properties of thin film—substrate system. Thin film-semiconductor sample (in our case Silicon) is modeled by simultaneous analysis of the plasma, thermal, and elastic wave equations. Multireflection effects in thin film are included in theoretical model and analyzed. Relations for the amplitude and phase of electronic and thermal elastic bending in the optically excited two-layer mechanically-supported circular plate are derived. Theoretical analysis of the thermodiffusion, plasmaelastic, and thermoelastic effects in a sample-gas-microphone photoacoustic detection configuration is given. Two normalization procedures of the photoacoustic elastic bending signal in function of the modulation frequency of the optical excitation are established. Given theoretical model can be used for various photoacoustic detection configurations, for example, in the study of optical, thermal, and elastic properties of the dielectric-semiconductor or metal-semiconductor structure, etc., Theoretical analysis shows that it is possible to develop new noncontact and nondestructive experimental method—PA elastic bending method for thin film study, with possibility to obtain the optical, thermal, and elastic parameters of the film thinner than 1 μm.

  7. Optical properties of thermally evaporated tin-phthalocyanine dichloride thin films, SnPcCl{sub 2}

    Energy Technology Data Exchange (ETDEWEB)

    El-Nahass, M.M.; Abd-El-Rahman, K.F.; Al-Ghamdi, A.A.; Asiri, A.M

    2004-02-15

    The optical properties of tin-phthalocyanine dichloride thin films have been studied. The films used in the characterisation studies were thermally evaporated. The spectral and optical parameters have been investigated using spectrophotometric measurements of transmittance and reflectance in the wavelength range 200-2100 nm. The absorption spectra recorded in UV-VIS region for the as-deposited and annealed samples showed two absorption bands, namely the Q- and Soret band. No remarkable effect was observed after annealing. A structure with energy separation of magnitude 0.2 eV is seen on the Q- and Soret bands. A transition involving d-electrons of the central metal atom was indicated in the high photon energy region. The dispersion curve of the refractive index showed an anomalous dispersion in the absorption region and a normal one in the transparent region. The band-model theory was applied to determine the optical parameters. The fundamental and the onset of the indirect energy gaps were determined to be 2.79 and 1.51 eV respectively.

  8. Structural, optical and thermal properties of {beta}-SnS{sub 2} thin films prepared by the spray pyrolysis

    Energy Technology Data Exchange (ETDEWEB)

    Khelia, C.; Ben Nasrallah, T.; Amlouk, M.; Belgacem, S. [Faculte des Sciences, Tunis (Tunisia). Lab. de Physique de la Matiere Condensee; Maiz, F. [Equipe de Photothermique de Nabeul, Inst. Preparatoire aux Etudes d' Ingenieur de Nabeul (Tunisia); Mnari, M. [Lab. de Chimie Analytique, Campus Univ., Tunis (Tunisia)

    2000-03-01

    Tin disulfide {beta}-SnS{sub 2} thin films have been prepared on pyrex substrates by the spray pyrolysis technique using tin tetrachloride and thiourea as starting materials. The depositions were carried out in the range of substrate temperatures from 240 to 400 C. Highly c-axis oriented {beta}-SnS{sub 2} films, having a strong (001) X-ray diffraction line are obtained at temperature 280 C and using concentration ratio in solution R = [S]/[Sn] = 2.5. Films surfaces were analyzed by contact atomic force microscopy (AFM) and by scanning electron microscopy (SEM) in order to understand the effect of the deposited temperature on the surface structure. On the other hand, from transmission and reflection spectra, the band gap energy determined is about 2.71 eV. Finally using the photodeflection spectroscopy technique, the thermal conductivity K{sub c} and diffusivity D{sub c} were obtained. Their values are 10 Wm{sup -1}K{sup -1} and 10{sup -5} m{sup 2}s{sup -1} respectively. (orig.)

  9. Magneto-thermo-elastokinetics of Geometrically Nonlinear Laminated Composite Plates. Part 1: Foundation of the Theory

    Science.gov (United States)

    Hasanyan, Davresh; Librescu, Liviu; Qin, Zhanming; Ambur, Damodar R.

    2006-01-01

    A fully coupled magneto-thermo-elastokinetic model of laminated composite, finitely electroconductive plates incorporating geometrical nonlinearities and subjected to a combination of magnetic and thermal fields, as well as carrying an electrical current is developed, In this context. the first-order transversely shearable plate theory in conjunction with von-Karman geometrically nonlinear strain concept is adopted. Related to the distribution of electric and magnetic field disturbances within the plate, the assumptions proposed by Ambartsumyan and his collaborators are adopted. Based on the electromagnetic equations (i.e. the ones by Faraday, Ampere, Ohm, Maxwell and Lorentz), the modified Fourier's law of heat conduction and on the elastokinetic field equations, the 3-D coupled problem is reduced to an equivalent 2- D one. The theory developed herein provides a foundation for the investigation, both analytical and numerical, of the interacting effects among the magnetic, thermal and elastic fields in multi-layered thin plates made of anisotropic materials.

  10. Design Guideline for New Generation of High-Temperature Guarded Hot Plate

    Science.gov (United States)

    Wu, J.; Hameury, J.; Failleau, G.; Blahut, A.; Vachova, T.; Strnad, R.; Krause, M.; Rafeld, E.; Hammerschmidt, U.

    2018-02-01

    This paper complements the existing measurement standards and literature for high-temperature guarded hot plates (HTGHPs) by addressing specific issues relating to thermal conductivity measurement of technical insulation at high temperatures. The examples given are focused on the designs of HTGHPs for measuring thin thermal insulation. The sensitivity studies have been carried out on major influencing factors that affect the thermal conductivity measurements using HTGHPs, e.g., the uncertainty of temperature measurements, plate flatness and center-guard gap design and imbalance. A new configuration of center-guard gap with triangular shape cross section has been optimized to obtain the same thermal resistance as a 2 mm wide gap with rectangular shape cross section that has been used in the HTGHPs at NPL and LNE. Recommendations have been made on the selections of heater plate materials, high-temperature high-emissivity coatings and miniature temperature sensors. For the first time, thermal stress analysis method has been applied to the field of HTGHPs, in order to estimate the effect of differential thermal expansion on the flatness of thin rigid specimens during thermal conductivity tests in a GHP.

  11. Radiative characteristics of a thin solid fuel at discrete levels of pyrolysis: Angular, spectral, and thermal dependencies

    Science.gov (United States)

    Pettegrew, Richard Dale

    Numerical models of solid fuel combustion rely on accurate radiative property values to properly account for radiative heat transfer to and from the surface. The spectral properties can change significantly over the temperature range from ambient to burnout temperature. The variations of these properties are due to mass loss (as the sample pyrolyzes), chemical changes, and surface finish changes. In addition, band-integrated properties can vary due to the shift in the peak of the Planck curve as the temperature increases, which results in differing weightings of the spectral values. These effects were quantified for a thin cellulosic fuel commonly used in microgravity combustion studies (KimWipesRTM). Pyrolytic effects were simulated by heat-treating the samples in a constant temperature oven for varying times. Spectral data was acquired using a Fourier Transform Infrared (FTIR) spectrometer, along with an integrating sphere. Data was acquired at different incidence angles by mounting the samples at different angles inside the sphere. Comparisons of samples of similar area density created using different heat-treatment regimens showed that thermal history of the samples was irrelevant in virtually all spectral regions, with overall results correlating well with changes in area density. Spectral, angular, and thermal dependencies were determined for a representative data set, showing that the spectral absorptance decreases as the temperature increases, and decreases as the incidence angle varies from normal. Changes in absorptance are primarily offset by corresponding changes in transmittances, with reflectance values shown to be low over the tested spectral region of 2.50 mum to 24.93 mum. Band-integrated values were calculated as a function of temperature for the entire tested spectral region, as well as limited bands relevant for thermal imaging applications. This data was used to demonstrate the significant error that is likely if incorrect emittance values are

  12. Effects of Ramped Wall Temperature on Unsteady Two-Dimensional Flow Past a Vertical Plate with Thermal Radiation and Chemical Reaction

    Directory of Open Access Journals (Sweden)

    V. Rajesh

    2014-08-01

    Full Text Available The interaction of free convection with thermal radiation of a viscous incompressible unsteady flow past a vertical plate with ramped wall temperature and mass diffusion is presented here, taking into account the homogeneous chemical reaction of first order. The fluid is gray, absorbing-emitting but non-scattering medium and the Rosseland approximation is used to describe the radiative flux in the energy equation. The dimensionless governing equations are solved using an implicit finite-difference method of the Crank-Nicolson type, which is stable and convergent. The velocity profiles are compared with the available theoretical solution and are found to be in good agreement. Numerical results for the velocity, the temperature, the concentration, the local and average skin friction, the Nusselt number and Sherwood number are shown graphically. This work has wide application in chemical and power engineering and also in the study of vertical air flow into the atmosphere. The present results can be applied to an important class of flows in which the driving force for the flow is provided by combination of the thermal and chemical species diffusion effects.

  13. Micro-channel plate detector

    Science.gov (United States)

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

    2015-09-22

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

  14. Phonon thermal conductivity of scandium nitride for thermoelectrics from first-principles calculations and thin-film growth

    DEFF Research Database (Denmark)

    Kerdsongpanya, Sit; Hellman, Olle; Sun, Bo

    2017-01-01

    The knowledge of lattice thermal conductivity of materials under realistic conditions is vitally important since many modern technologies require either high or low thermal conductivity. Here, we propose a theoretical model for determining lattice thermal conductivity, which takes into account...

  15. Determination of the Glass Transition Temperature of Freestanding and Supported Azo-Polymer Thin Films by Thermal Assisted Atomic Force Microscopy

    Science.gov (United States)

    Chernykh, Elena; Kharintsev, Sergey; Fishman, Alexandr; Alekseev, Alexander; Salakhov, Myakzuym

    2017-03-01

    In this paper we introduce and apply the method for determination of the glass transition temperature of the sub-100 nm thick freestanding and supported polymer films based on thermally assisted atomic force microscopy (AFM). In proposed approach changes of the phase of an oscillating AFM cantilever are used to determine glass transition temperature. An anomalous decrease of the glass transition temperature for both free-standing and supported azobenzene-functionalized polymer thin films is shown.

  16. Impact of ink synthesis on processing of inkjet-printed silicon nanoparticle thin films: A comparison of Rapid Thermal Annealing and photonic sintering

    Energy Technology Data Exchange (ETDEWEB)

    Drahi, E.; Blayac, S. [Centre Microélectronique de Provence/Ecole Nationale Supérieure des Mines de Saint Etienne, 880, avenue de Mimet Gardanne, 13541 (France); Borbely, A. [Science des Matériaux et des Structures/Ecole Nationale Supérieure des Mines de Saint Etienne, 158, cours Fauriel Saint Etienne Cedex 2, 42023 (France); Benaben, P. [Centre Microélectronique de Provence/Ecole Nationale Supérieure des Mines de Saint Etienne, 880, avenue de Mimet Gardanne, 13541 (France)

    2015-01-01

    Inkjet printing has a high potential for cost reduction in solar cell and thermoelectric industry. This study demonstrates that silicon thin films can be produced by inkjet-printing of silicon nanoparticles followed by subsequent drying and annealing steps. Ink formulation is crucial for the sintering of the silicon nanoparticles and control of the microstructure at low temperature. Upon heating, the microstructure is modified from porous layer made of juxtaposed silicon nanoparticles to denser layer with coarser grains. This evolution is monitored by scanning electron microscopy and by micro-Raman spectroscopy, which offer a fast and precise characterization of the microstructure and chemical composition of thin films. Above a threshold temperature of 800 °C cracks appear within thin film and substrate because of the stress induced by the oxidation of the surface. An innovative sintering method, photonic annealing, is studied in order to reduce both oxidation and stress in the thin films as well as reducing processing time. Evolution of the thermal conductivity is performed by micro-Raman spectroscopy and can be tailored in a large range between ~ 1 and ~ 100 W·m{sup −1}·K{sup −1} depending on the sintering method and atmosphere. Therefore control of the microstructure evolution with applied annealing process allows tailoring of both microstructure and thermal conductivity of the silicon thin films. - Highlights: • Impact of ink synthesis on sintering (Si nanoparticle surface chemistry) • Photonic annealing of inkjet printed Si nanoparticles • Micro-Raman spectroscopy and X-Ray Diffraction for thin film characterization.

  17. Comparative of the Tribological Performance of Hydraulic Cylinders Coated by the Process of Thermal Spray HVOF and Hard Chrome Plating

    Directory of Open Access Journals (Sweden)

    R.M. Castro

    2014-03-01

    Full Text Available Due to the necessity of obtaining a surface that is resistant to wear and oxidation, hydraulic cylinders are typically coated with hard chrome through the process of electroplating process. However, this type of coating shows an increase of the area to support sealing elements, which interferes directly in the lubrication of the rod, causing damage to the seal components and bringing oil leakage. Another disadvantage in using the electroplated hard chromium process is the presence of high level hexavalent chromium Cr+6 which is not only carcinogenic, but also extremely contaminating to the environment. Currently, the alternative process of high-speed thermal spraying (HVOF - High Velocity Oxy-Fuel, uses composite materials (metal-ceramic possessing low wear rates. Research has shown that some mechanical properties are changed positively with the thermal spray process in industrial applications. It is evident that a coating based on WC has upper characteristics as: wear resistance, low friction coefficient, with respect to hard chrome coatings. These characteristics were analyzed by optical microscopy, roughness measurements and wear test.

  18. Low order modelling and closed-loop thermal control of a ventilated plate subject to a heat source disturbance

    Science.gov (United States)

    Videcoq, E.; Girault, M.; Petit, D.

    2012-11-01

    A multi-input multi-output (MIMO) thermal control problem in real-time is investigated. An aluminum slab is heated on one side by a radiative heat source and cooled on the other side by a fan panel. Starting from a nominal steady state configuration of heat source power and ventilation level, the objective is to control temperature at 4 chosen locations on the rear side when the thermal system is subject to a perturbation: the heat source power. The 4 actuators are the ventilation levels of 4 fans. The hypothesis of small inputs and temperature responses deviations is made, resulting in the assumption of a linear control problem. The originality of this work is twofold: (i) instead of a (large-sized) classical heat transfer model built from spatial discretization of local partial differential equations governing physics over the system domain, a low order model is identified from experimental data using the Modal Identification Method, (ii) this low order model is used to perform state feedback control in real time through a Linear Quadratic Gaussian (LQG) compensator.

  19. Experimental and numerical investigation on thermal fluid-structure interaction on ceramic plates in high enthalpy flow

    Science.gov (United States)

    Willems, Sebastian; Esser, Burkard; Gülhan, Ali

    2015-12-01

    A detailed knowledge of the fluid-structure interaction in hypersonic flows is important for the design of future space transportation systems. The thermal aspect of such an interaction was investigated with the help of a generic model in the arc-heated wind tunnel L3K at the German Aerospace Center in Cologne. Flat and curved panels of the fibre-reinforced ceramics C/C-SiC with and without anti-oxidation coating where used. Several configurations with and without back plane insulation were tested at 10° and 20° angle of attack. The panel heating was measured with an infrared camera, several thermocouples and pyrometers. The experimental results show the influence of the shape as well as of radiation cooling and radiation heating. The experiments also reveal the effect of additional heating due to recombination of atomic oxygen on the surface. At certain configurations a local temperature peak moved over the panel. This thermal wave is also influenced by the silicon carbide coating. The analysis is supported by coupled fluid and structure simulations.

  20. In{sub 6}Se{sub 7} thin films by heating thermally evaporated indium and chemical bath deposited selenium multilayers

    Energy Technology Data Exchange (ETDEWEB)

    Ornelas, R.E.; Avellaneda, D. [Universidad Autonoma de Nuevo Leon, Facultad de Ingenieria Mecanica y Electrica, San Nicolas de los Garza, Nuevo Leon-66450 (Mexico); Shaji, S. [Universidad Autonoma de Nuevo Leon, Facultad de Ingenieria Mecanica y Electrica, San Nicolas de los Garza, Nuevo Leon-66450 (Mexico); Universidad Autonoma de Nuevo Leon-CIIDIT, Apodaca, N.L (Mexico); Castillo, G.A.; Roy, T.K. Das [Universidad Autonoma de Nuevo Leon, Facultad de Ingenieria Mecanica y Electrica, San Nicolas de los Garza, Nuevo Leon-66450 (Mexico); Krishnan, B., E-mail: kbindu_k@yahoo.com [Universidad Autonoma de Nuevo Leon, Facultad de Ingenieria Mecanica y Electrica, San Nicolas de los Garza, Nuevo Leon-66450 (Mexico); Universidad Autonoma de Nuevo Leon-CIIDIT, Apodaca, N.L (Mexico)

    2012-05-15

    Indium selenide (In{sub 6}Se{sub 7}) thin films were prepared via selenization of thermally evaporated indium thin films by dipping in sodium selenosulphate solution followed by annealing in nitrogen atmosphere. First, indium was thermally evaporated on glass substrate. Then, the indium coated glass substrates were dipped in a solution containing 80 ml 0.125 M sodium selenosulphate and 1.5 ml dilute acetic acid (25%) for 5 min. Glass/In-Se layers were annealed at 200-400 Degree-Sign C in nitrogen atmosphere (0.1 Torr) for 30 min. X-ray diffraction studies showed the formation of monoclinic In{sub 6}Se{sub 7}. Morphology of the thin films formed at different conditions was analyzed using Scanning electron microscopy. The elemental analysis was done using Energy dispersive X-ray detection. Electrical conductivity under dark and illumination conditions was evaluated. Optical band gap was computed using transmittance and reflectance spectra. The band gap value was in the range 1.8-2.6 eV corresponding to a direct allowed transition. We studied the effect of indium layer thickness and selenium deposition time on the structure, electrical and optical properties of In{sub 6}Se{sub 7} thin films.