Total solar reflectance

Ti02 particles in HDPE matrix aid the polymer chains in crystalhzing into more perfect and thermally stable lamella. The number of nucleation sites is dramatically increased and the crystal size decreased. The solar reflectance was related to the degree of crystallinity, the spherulite size of HDPE, refractive index, and distribution of Ti02 particles in HDPE matrix. The ratile Ti02 increased the total solar reflectance from 28.2 to 51.1%. ... 

This equation is also valid for z should the need arise to characterize a nonopaque object. For a more thorough treatment of this calculation, see ASTM E903 [3]. Because the total solar reflectance calculates the amount of sunlight that is not absorbed on a surface, it is the key factor in determining the heat gained in sunlight... 

Color formulators are typically limited in their choice of resins for a given application. This is seldom a problem due to the high emissivity of most organic resins. They do have more control over the pigment systems, which controls the total solar reflectance. To demonstrate the effectiveness of these choices, we need to look at test methods. 

Fig. 8.25. Quantum efficiency QE and cell absorption (1 — R) curves of pc-Si H pin solar cells (i-layer thickness 1.2 pm, ZnO/Ag back reflector) for front ZnO Al with different thickness 330nm (dashed), 870nm (dotted), and 1 370nm (solid). R is total cell reflectance. Sheet resistance of the front contacts as well as FF and Jsc of the solar cells are given in Table 8.4...

Fig. 4.6. Incident light is deflected in a corrugated thin film solar cell, leading to total internal reflection at the interface with the substrate and at the front surface...

For applying this condition, in turn it is necessary to expand the total solar radiative flux entering trough the tube wall (formed by the directly incident part plus that reflected by the mirrors) into a Fourier series... 

If one takes the global view of the energy stored in biomass compared to the total solar energy incident on the Earth, then the estimated overall efficiency is about 0.05%.This includes losses due to reflection, absorption by nonphotosynthetic pigments, the fact that much of the solar output is in the near-infrared region, which is not efficiently used by abundant organisms, and various cellular processes. 

Before the second 50 mm OD quartz reactor arrived from Princeton, several exploratory experiments were performed using a 50 mm OD vycor tube with rubber corks and steel inlets for the biomass and steam, and a gas exit. The reactor functioned well when exposed to the solar flux (1000 w/cm ) and some semi-quantitative data was obtained however because the rubber corks partially melted under exposure to the radiation flux carried up and down the walls of the vycor tube by total internal reflection, little significance could be attached to the data. 

Up to this point we have assumed that only the aerosol in the atmosphere produces scattering and absorption. Actually the atmosphere itself, even if totally devoid of particles, does not completely transmit the incident solar beam. Let Ta denote the fractional transmittance of the atmosphere. It is useful to think of the atmosphere as overlaying the aerosol layer. Then, instead of Fo, the incident flux on the aerosol layer is TaF0. The total upward reflected flux, given by (24.4), is now corrected as follows ... 

The fraction of the total solar radiation incident on a body that is reflected by it. 

Once the sun s irradiance and material s optical properties are integrated at each wavelength, the total of reflected solar energy may be summed resulting in a single number denoted as total percent solar reflectance for the air mass used. Percent solar absorptance is then calculated ... 

On the other hand, Baldini et al. (2002) hypothesized that water stress caused accelerated and earlier embryo development and lipid accumulation. This therefore caused a shorter duration of all enzymatic activities, including those of ODS and this could reflect on the final fatty acid composition. Both oleic and linoleic acid concentrations of the oil of cultivated sunflower were significantly related to total solar radiation and day length (Seiler, 1983). A positive association between intercepted solar radiation and oleic acid percentage has been reported for sunflower (Seiler, 1986 Echarte et al., 2010) and soybean oil (Kane et al., 1997). 

This emission is trapped by total internal reflection and concentrated at the edge of the collector by the geometrical shape, which is usually a thin plate. Thus, the concentration of light trapped in the plate is proportional to the ratio of the surface area to the edges. The advantages of LSCs over conventional solar concentrators are as follows ... 

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