Some of the properties of optical transmission caused by floating particles such as soot and smoke in highway tunnels were considered.Highway tunnels are provided with many kinds of equipment such as ventilation systems, lighting systems, and security systems including video cameras. The properties of optical transmission play an important part in designing and controling the above-mentioned equipment. As a result of an experimental study it was found that the spectral transmittance τ (λ) of soot and smoke in highway tunnels was described by the equation,
τ(λ)=10^{-E₀(λ/λ₀)-λ}=10^-kλ-γDιWhere λ is the wavelength of light, E₀ is the spectral absorbance, γ is the wavelength factor, D is the density of soot and smoke in highway tunnels, and ι is the thickness of the atmosphere in highway tunnels. We found that the wavelength factor γ differed from each typical highway tunnel in Japan and extended from 1.0 to 1.3. Also we supposed that these properties of spectral transmission were dependent on the diameter of soot and smoke particles in highway tunnels by the experimental results and numerical calculations.

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People can immediately understand how a room is illuminated when s/he enters the room. The state is called that s/he got the Recognized Visual Space of Illumination (RVSI) for the room. To get a RVSI one utilizes the appearance of objects and light source in the room as the initial visual information. One can suppose then that a RVSI can be altered by changing the initial visual information such as lightness and color of the objects. We measured, in Experiment 1, the illuminance of a test room to equate the brightness appearance of the room with that of a standard room when the lightness of objects in the test room was made lower compared to that of the standard room, when all the objects of both rooms were made of grey surface. A higher illuminance was needed for the test room to get the equality implying that lower lightness produced a smaller RVSI in the subjects brain when both rooms were illuminated to a same illuminance. In Experiment 2, colored surfaces were employed for objects in the test room to investigate the effect of color as well as of its saturation upon the RVSI. Less illuminance was need to get the equality of brightness appearance of space when the color was used for the objects in the test room and still less illuminance was needed if more saturated color was used for the objects in the test room, while keeping the standard room grey. Colored objects produced a larger RVSI in the subjects brain than grey objects.

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The operating circuit for an electrodeless HID discharge consists of a high frequency power supply, a matching circuit and an exciting coil. This paper shows that a resonant circuit consisting of an exciting coil and a matching circuit with high Q value has difficultly in starting the discharge even if the circuit component values are changed slightly.
In the control method presented here the operating frequency is controlled in order to keep the phase angle of the input impedance of the matching circuit constant.
By using this method, the starting of the lamp is improved even if the circuit component values are change

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This study was conducted to evaluate the physiological and psychological effects of illuminance in an office space during the performance of monotonous tasks.
A series of experiments were carried out in an experimental room that simulated anactual office space. The experimental factor was the illuminance on the working plane, and there were four illuminance levels increasing in geometric progression: 200, 500, 1250 and 3125lx. The physiological and psychological measurements used were electroencephalogram (EEG), finger photoelectric plethysmogram (PTG), heart rate, kwansei-gwakuin sleepiness scales (KSS) etc.
1) Analysis of EEG and KSS showed that the subjects' activation levels remained higher under the conditions of 500lx and 1250lx.
2) Analysis of PTG and heart rate showed that the subjects were relaxed under conditions of 5001x and 1250lx.
The results show that to a certain extent low or high illuminance levels are not suitable for the performance of the VDT vigilance task.

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The temperature rise, heat flow and drying rate of a water containing flat substance heated by long-wave infrared radiation and/or hot-air convection are analyzed on a simulated electrical resistance-capacitance network that is equivalent to a given thermal system. The analysis assumes that only the surface of the substance is heated and that the substrate is heated only by thermal conduction. It also assumes that the irradiated heat flow input, apart from the hot-air input, is constant and that the heated substance behaves like pure water.
The analysis shows that the heating system that uses infrared radiation with hot-air convection can be reduced to an equivalent system that uses infrared radiation.This can be done by introducing a new-defined evaporation resistor and convection heat transfer resistor, and by applying transformation theorem of the voltage source (simulating hot-air temperature) into the current source (simulating heat flow supplier), which is known as electrical circuit analysis.
Since thermal systems are generally nonlinear, and thus different from linear electrical circuits, the ratio of the evaporation resistor to the convection heat transfer resistor depends on temperature. The ratio versus temperature characteristic is analyzed theoretically and is checked against published numerical experimental data. Theoretical values of the above ratio can be put into the drying rate formula which is obtained by simulating linear electrical circuit analysis. The results are checked against published numerical experimental data.

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In order to investigate the effect of visual acuity on the luminous efficiency function determined by heterochromatic brightness matching (HBM), the spectral luminous efficiency function and visual acuity were measured for 15 observers including 8 high-acuity and 7 low-acuity observers under three artificially corrected conditions: high acuity, low acuity and no correction. It was found that the shape of the spectral luminous efficiency function did not differ between the two groups with high-acuity and low-acuity nor among the three artificially corrected acuity conditions. These findings were confirmed by principal component analysis of the data. It is concluded that it is difficult to classify the type of luminous efficiency function for brightness by considering the visual acuity of an observer.

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The correlated color temperature (CCT) of total skylight, which comes to a horizontal plane from all sky components, varies hourly with atmospheric transmittance pv and the amount of cloud m. The parameter pvcaused by visible solar radiation is calculated from the atmospheric transmittance based on direct solar radiation. A new practical formula for estimating the CCT of the total skylight is proposed. Using the formula, the CCTs of the total skylight at 14 areas in Japan are calculated from the parameter pv and the number of days that is calculated from the parameter m. Consequently, it is estimated that variation in the CCT of daylight is 5900K to 8000K. The mean CCT of total skylight is 6800K, where the mean CCT of global light is 5900K and that of the total skylight for the parameter m=0 is 8000K.

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In this paper the authors make clear of the meaning of illuminance calculation formulae of contour integration method of Higo and Shinoda, and the interrelation between this method, and another modified contour integration methods of Kamisaka, Omoto, etc.

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A room beyond a window can be perceived continuously from an observer's room if the illuminance level of the latter rom is properly adjusted. This is achieved by equating the two RVSIs, or the recognized visual spaces of illumination, of the rooms and can be applied to the lighting of houses to enhance the amenity for residents. In designing the lighting environment, it is convenient if there exists some tolerable illuminance range for the continuity of perception. The range for the two rooms, the observer's room and the reference room connected by an open square (simulating a study and a kitchen) was determined experimentally. The range was fairly large and it was roughly proportional to the illuminance of the reference room.

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When an observer outside a room looks in through a window, s/he gains two Recognized Visual Spaces of Illumination, RVSIs, one for the room and the other for the outside where the observer stays. By adjusting the illuminance of the room the two RVSIs can be made equal and the observer perceives continuity between the two spaces, or in other words, s/he feels the two spaces are one. The illuminance level of a room in a normal living house in the early morning and in the evening when the illuminance of outside rapidly changes was determined experimentally. It was found that the room illuminance can be expressed as a simple linear equation of the outside illuminace when both illuminances are expressed in logarithms. Some cases where this in-phase illumination may be useful are suggested.

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