Sapphire

Pishchik, Valerian; Lytvynov, Leonid A.; Dobrovinskaya, Elena R.

doi:10.1007/978-0-387-85695-7

Cited by 58 publications

(28 citation statements)

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“…In comparison with former results obtained by FEM simulation [7] the current results seem to be more realistic since laser irradiation, wetting behavior of Al 2 O 3 and braze material as well as Fresnel absorption is taken into consideration in the described model. The findings indicate no transgression of the melting temperature of Al 2 O 3 of 2323 K [28] during one joining cycle, which was also confirmed in the experiments. A low pressure of 120 mbar was chosen for this rather complex model, since higher pressures result in higher gas velocities, which results in a larger number of time steps necessary to be computed during the simulation which significantly increases simulation times.…”

Section: Time-temperature Cycle Of the Capillary During Joiningsupporting

confidence: 75%

Experimental and numerical investigations regarding laser drop on demand jetting of Cu alloys

Stein

Dobler

Radel

et al. 2017

Prod. Eng. Res. Devel.

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model was set up, indicating heating and cooling rates of 22,100 K/s. Further, the impact of the capillary geometry on the velocity fields of a passing medium was evaluated. By changing the capillary geometry, the gas flow velocity could be reduced by about 10% according to the simulation model, which resulted in a reduction of droplet height deviation of 7.5% and a reduction of the droplet diameter deviation of 32.2% in the experiment.

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Section: Time-temperature Cycle Of the Capillary During Joiningsupporting

confidence: 75%

Experimental and numerical investigations regarding laser drop on demand jetting of Cu alloys

Stein

Dobler

Radel

et al. 2017

Prod. Eng. Res. Devel.

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“…Also shown (open triangles) are the results for heaters on four bare sapphire substrates; the solid line shows ΔT/P calculated with κ sapphire = 38.9 ± 0.8 W/m•K, consistent with the published value. 11 The dashed line shows the calculated value of ∆T/P for a 500 nm thick film of TES-ADT assuming our measured bulk crystal thermal conductivity value κ c = 5.5 W/m•K. The solid symbols show our measurements on vapor annealed TES-ADT films made from different starting solutions while the open circles and open diamonds show results for two spin-cast but non-annealed (i.e.…”

Section: Sample Preparationmentioning

confidence: 99%

“…the direction of crystal growth and highest electronic conductivity) thermal conductivity of bis(triisopropylsilylethynyl) pentacene (TIPS-pn [7][8][9][10] ) κ needle ≈ 1.6 W/m⋅K, 4 the inter-plane (caxis) thermal conductivity has been measured, using an ac-photothermal technique, 5 to be κ c ≈ 21 W/m⋅K, a value close to that of sapphire. 11 As discussed below, this large value and inverted anisotropy (i.e. κ c > κ needle ) has tentatively been associated with heat flowing between layers via interactions between librations of alkyl chains terminating the silylethynyl sidegroups on the molecules.…”

Section: Introductionmentioning

confidence: 94%

Thermal resistances of thin films of small molecule organic semiconductors

et al. 2016

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Abstract:We have measured the thermal resistances of thin films of the small molecule organic semiconductors bis(triisopropylsilylethynyl) pentacene (TIPS-pn), bis(triethylsilylethynyl) anthradithiophene (TES-ADT) and difluoro bis(triethylsilylethynyl) anthradithiophene (diF-TES-ADT). For each material, several films of different thicknesses have been measured to separate the effects of intrinsic thermal conductivity from interface thermal resistance. For sublimed films of TIPS-pn and diF-TES-ADT, with thicknesses ranging from < 100 nm to > 4 µm, the thermal conductivities are similar to that of polymers and over an order of magnitude smaller than that of single crystals, presumably reflecting the large reduction in phonon mean-free path in the films. For thin (≤ 205 nm) crystalline films of TES-ADT, prepared by vapor-annealing spin-cast films, the thermal resistances are dominated by interface scattering.

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“…The absorption by the air is reduced by placing the camera relatively close to the set-up, so that the transmittance of the air can be assumed to be close to 1. As described before, we used a sapphire glass front window for its high transmittance [25]. The reflection of environment, on the other hand, is minimized by performing the experiment in a closed unit without interference of any warm objects.…”

Section: Ir Camera and Calibrationmentioning

confidence: 99%

Experimental and simulation study of heat transfer in fluidized beds with heat production

Janssen

Buist

et al. 2017

Chemical Engineering Journal

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h i g h l i g h t sHeat production in a fluidized bed by CO 2 adsorption on Zeolite 13X. Combined infrared/visual camera (PIV-DIA-IR) technique for studying heat transfer. Extensive validation though a combined CFD-DEM model. Key aspects of adsorption process studied with TGA and STA. a r t i c l e i n f o b s t r a c tAs a result of highly exothermic reactions during gas-phase olefin polymerization in fluidized bed reactors, difficulties with respect to the heat management play an important role in the optimization of these reactors. To obtain a better understanding of the particle temperature distribution in fluidized beds, a high speed infrared (IR) camera and a visual camera have been coupled to capture the hydrodynamic and thermal behavior of a pseudo-2D fluidized bed. The experimental data were subsequently used to validate an in-house developed computational fluid dynamics and discrete element model (CFD-DEM). In order to mimic the heat effect due to the exothermic polymerization reaction, a model system was used. In this model system, heat is released in zeolite 13X particles (1.8-2.0 mm, Geldart D type) due to the adsorption of CO 2 . All key aspects of the adsorption process (kinetics, equilibrium and heat effect) were studied separately using Thermogravimetric Analysis (TGA) and Simultaneous Thermal Analysis (STA), and subsequently fluidized bed experiments were conducted, by feeding gas mixtures of CO 2 and N 2 with different CO 2 concentrations to the bed, where the total heat of liberation could be controlled. The combined infrared/visual camera technique generated detailed information on the thermal behavior of the bed. Furthermore, the comparison of the spatial and temporal distributions of the particle temperature measured in the fluidized bed with the simulation results of CFD-DEM provides qualitative and quantitative validation of the CFD-DEM, in particular concerning the thermal aspects.

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Sapphire

Cited by 58 publications

References 0 publications

Experimental and numerical investigations regarding laser drop on demand jetting of Cu alloys

Experimental and numerical investigations regarding laser drop on demand jetting of Cu alloys

Thermal resistances of thin films of small molecule organic semiconductors

Experimental and simulation study of heat transfer in fluidized beds with heat production

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