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Experimental Study of Effects of ArtificialLight
Sources on the Coloring of Fig Fruits
Tetsuo KADONAGA, Shinichi KOHSAKA and Hitoshi YANAGIHARA
In the green house cultivation to diversify harvest
times, supplemental lighting systems are necessary to
compensate the lack of sun light. Besides, artificial
light sources of the system for fig fruits are needed
to accelerate the coloring.
Paying attention that matured figs have reddish
violet colors in general, using harvested figs, colors
and quantities of pigments (anthocyanin) on their surfaces
are investigated. On cultivating processes, figs are
radiated by artificial light sources with different
spectral distributions.
By studying comparisons between spectral distribution
of light sources and experimental results, it is confirmed
that generations of pelargonidin and cyanidin in anthocyanin
are related to the coloring, and that two types of fluorescent
lamps are effective to generate pigments on surfaces
of figs. One type is for use of coping machine, and
the other is with three-band phosphors.
KEYWORD:green house, artificial light, spectral distribution,
fig fruits, coloring, anthocyanin
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Translucence Phenomenon of the Arc Tube for InductivelyCoupled
Electrodeless Metal Halide Lamps
Kozo UEMURA and Toshihiko ISHIGAMI
The translucence phenomenon of arc tubes for inductively
coupled electrodeless metal halide lamps was evaluated
and analyzed, methods for decreasing the translucence
were investigated.
The surface of the fused silica was found to be
etched in the hot region, and the fused silica was deposited
on the cold-region surface. The change in translucence
occurred as a result of this SiO2 transport phenomenon.
Effects of the lamp parameters were evaluated.
The translucence phenomenon is promoted under the condition
that the dose material contained rare-earth metal halides.
Another study showed that the partial pressures
of free metal atoms around the wall of the arc tube
(the pressures were controlled by adjusting the filled
Xe pressure and added SnI2 amount) strikingly affect
the translucence level.
The effects of the temperature of the arc tube and the
effects of the electric field created by the induction
coil were found to be not so great as the effects of
the lamp fills and the partial pressures of the free
atoms.
OH radicals in the fused silica, which may promote
the translucence change of the fused silica, were found
to invade the outer and inner surfaces of the arc tube
wall due to the use of an H2 - O2 burner in the bulb-forming
process.
Removal of these OH radicals with hydrofluoric-acid
surface-etching treatment strikingly decreased the translucence
change level.
Therefore, removing the OH radicals from the inner
surface of the arc tube is an important and basic condition
for decreasing the translucence level of arc tubes.
In arc tubes without an outer bulb, OH radicals
that originate in H2O vapor in air invade the arc tubes.
Calculation of distributions of OH radicals showed that
after 20,000 hours of operation of arc tubes with 1mm
thickness OH radicals reach the inner wall and the arc
tube becomes translucent.
This calculated result agreed well with the results
of life-time testing.
KEYWORD:translucence phenomenon. SiO2 transport, rare-earth
metal halide, free metal atom, OH radical
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A Method for Estimating Coloring Reproducibility
in the Test Samplesby Computer Color Matching
Kazuo SANO and Hiromitsu ISHII
The colors of industrial products such as cars,
houses, and fabrics are determined by a color matching
process. Color matching is a process in which colorants
and their ratios should be determined. There are two
methods for color matching, that is a visual color matching
method and a CCM (computer color matching) method which
is now used quite frequently. CCM can reduce the color
difference. However, color correction must be repeated
if there is poor color matching due to the limitations
in color reproducibility. In color reproducibility invesigation,
the same samples with the same colorant ratios must
be maked several times. However, it is difficult to
make several samples in the color matching process.
We used reflectance simulation in CCM to obtain reproducibility
in samples with different colorant ratios in color matching.
KEYWORD:CCM, computer color matching, coloring, reproducibility
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Variations in Illuminance Caused by Shadow under
Task Ambient Lighting?\Considering the Arrangement and
Luminous Flux of Ambient Light?\
Akira UCHIDA?CNaoki MATSUMOTO and Yoshihiko OHTANI
We examined the characteristics of shadows created
by task ambient lighting mounted on a ceiling on a work
surface (a desk) for various combinations of lighting
arrangements and luminous fluxes. Shadowing in work
areas has become of greater concern with the decrease
in illuminance on work surfaces due to the obstructions
created by modern office designs (e.g., room partitions).
We found that when the arrangement and flux produce
an illuminance uniformity ratio of greater than 0.7,
the maximum shadow factor is less than 0.6, and the
areas in shadow are less than 15% of the total area.
Application of this principle will enable the design
of more comfortable and efficient offices.
KEYWORD:Task Ambient Lighting, Monte Carlo method,
illuminance calculation, shadow
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