24 research outputs found
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Processing Experiments for Development of High-Efficiency Silicon Solar Cells
Get PDFFabrication of high-efficiency silicon solar cells requires processing technology capable of maintaining long bulk carrier lifetime and low surface recombination. Development of long-lifetime processing techniques using experimental designs based on statistical methods is described. The first three experiments investigated pre-oxidation cleans, phosphorus gettering, and a comparison of different phosphorus diffusion sources. Optimal processing parameters were found to depend on type of silicon material. 2 refs., 2 figs., 2 tabs
Advanced hypersonic vehicle component testing using pre-heated models and infrared scanning
No full textFluid-solid heat exchange in porous media for transpiration cooling systems
No full textThis paper presents a semi-analytical solution of the coupled differential equations for
fluid and solid phase in a one-dimensional porous medium in thermal non-equilibrium. The
thermal impulse response of the fluid and solid phases is used to determine the pressure
loss over the thickness of the material. Experimental data obtained from surface heating of
porous ZrB2 samples is compared to the theoretical model. The plenum pressure, surface
temperature and backside temperature are measured using pressure sensors, thermographic
imaging and thermocouple instrumentation The non-integer system identification (NISI)
approach is used to obtain the thermal impulse response which is then compared with
the model prediction. Plenum pressure rise and thermal impulse response of the heating
experiments are used to assess the volumetric heat transfer coefficient of the sample. Good
agreement is found between the simulated and experimental data for the temperature and
pressure measurements. The obtained heat transfer coefficients are between 2.1 · 104 and
6.8 · 104 W m−3 K−1
for mass fluxes of 10 to 244 g m−2
s
−1
