5.7 Calculation of artificial light and noise workplace laboratories "nit"
Objectives: To calculate the parameters of the artificial lighting. Determine the intensity of the sound sources to the levels of intensity, and to find the total noise level for all sources. All coefficients are taken from the data sheet [1]
We consider task - lighting, it provides regulatory light levels indoors and work sites outside of buildings. The ultimate goal is to determine the type of lamps and the number of lamps. Since the minimum target of discrimination at work with a PC pixel - one point of light, and its size is 0.28mm, it has to deal with the visual work of very high accuracy, a level II of visual work. And depending on the software used can be dealt with, both directly and with reverse contrast and contrast the nature of the object and the nature of the background can be anything: light, medium, dark. It should also be noted that the duration of the visual work is more than half of the working day. On the basis of these data, we conclude that the visual work has a level II with subclass "in". General lighting is 500 lux and 2000 lux illumination combined, including 200 lux lighting.
Since the work PC does not belong to the category of very fine, choose a system of general lighting.
Bulb Type LTB40; lamp power Pl = 40 W
Luminous flux Fl = 2200 lm
The luminaires with tubular fluorescent lamps are placed parallel to the wall with windows. Fixtures are arranged in rows, docking with each other.
Plans location of fixtures and their vertical orientation (Figure 8-1):
hn hp - defined; hn = 3 m hp = 0.8 m
The distance from the floor to the fixture hc = 0,2 (hn-hp) = 0.44 m;
The distance from the working surface to the lamp hcp = hn - hp - hc = 1.46
= 1,5 (for fluorescent lighting fixtures);
lc= hcp
lc = 1.5 * 1.46 = 2,19 m - the distance between the centers of the lamps.
Figure 16 - Plans location of fixtures
The calculation of the required number of lamps finds by the formula
Nсв=Sn/lc2, where Sn - The illuminating the room;
Nсв = 6 * 3/4, 79 = 3,76 ≈ 4
Used the method of utilization of luminous flux:
i= ab/( hp(a+b)),
i - Index of premises; a, b, hp - length, width, height of the room, if m i <0.5 or i> 5, the corresponding but-or i = 0.5 i = 5.
Our i = 6 * 3 / (0.8 * (6 +3)) = 2.5.
The coefficient of uneven lighting for fluorescent lamps z = 1.1. The safety factor for media containing less than 1mg/m3 dust and smoke, provided cleaning fixtures at least 4 times a year kz = 1.8
The reflection coefficient of the ceiling P = 0.5
Wall reflectance Pc = 0.3
The coefficient of luminous flux at a given index premises and reflection coefficients of the walls and ceiling ŋ = 0.48
Number of lamps:
N = (E * Sn * z *kz)/(Fl * Nсв * ŋ)
N = (500 * 18 * 1.1 * 1.5) / (2200 * 4 * 0.48) = 14850/4224 = 3.52
5.7.1 Calculation of the total noise
In the laboratory "NIT" 10 PCs and one server. The average noise level is 40 dB of single PC, a server 60dB. Objective: To determine the actual intensity of the sound sources to the levels of intensity and find the total noise level for all sources.
The actual intensity of sound determined by the formula
L = 10*lg(J/J0)
where J - the actual value of the power of sound, W/m2
J0 - the threshold values of sound power, W m-2 (J0 = 10-12 W/m2)
lg - logarithm of the decimal.
L = 10 * lg (J/ J0) = 10 * (lgJ - lg J0) = 10 * lgJ - 10 * lg J0
10 * lgJ = L + 10 * lg J0
lgJ = L/10 + lg J0
PC lgJ = 40/10 + lg10-12 = 4 - 12 = -8 W/m2
For the server lgJ = 60/10 + lg10-12 = 6 - 12 = -6 W/m2
the actual sound intensity for each PC -8 W m-2, the actual intensity of the sound server - 6 W/m2
The total noise from several sources with the same level of sound intensity or sound pressure L1 (dB) can be determined from
L = L1 + 10lgn
where n - the number of noise sources;
L1 - a source of noise, dB
L = 40 + 10lg10 = 40 + 10 = 50 dB
The noise level from all of the computers is 50 dB.
To determine the total noise level using a formula
L = Lb + ∆
Where Lb - the larger of the folding noise sources dB.
Δ - «additive" at addition levels from two sources dB
L1 - L2 = 60 - 50 = 10dB
If the noise is 10dB difference, Δ = 0,45
L = Lb + Δ = 60 + 0.45 = 60.45 dB
The total noise level in the laboratory "NIT" is 60.45 dB. This is the optimal level of noise exceeds the laboratory.
5.7.2 Anthropogenic impact of the object on the environment and measures for environmental safety
In the laboratory "NIT" is nothing harmful to the environment. But the production of PCs may make changes in the ecology of the environment. Hazardous waste production is available on any industrial enterprise. This hire and stamping and sheet bending processes in the production cycle of computer technology. It is characterized as waste metal chips and scale, using water cycle industrial water cooled, using alkali and oils emulsions, gas emission from the heating furnaces. Modern automatic production of metal products has high environmental performance. It all depends on the enterprise, how it is prepared to go to meet nature. Enterprises using modern technology and environmentally friendly production with a certificate of ISO 14001 inflict minimal damage to nature.
CONCLUSION
In the thesis project written analysis of domestic and foreign works related to the theme of the graduation project, classification and comparative analysis of software systems on the market. Features used tools and technologies for the Android OS with a centralized repository for contact information address book. This app is designed for different age groups, having a mobile phone running on OS Android. With the app, you can restore the contact data of the mobile phone, in case of accidental data loss. During the development used Eclipse platform.
This application will be distributed for free on the store Google Play. Google Play is application store from Google, which allows owners of devices with the Android operating system to install and take a variety of applications. Each user of a mobile phone with Android OS can download and use the application. If successful, this app will also be available on Google Play, but for a fee.