Ngā Tātai mō te Kaha o te Oro me te Taumata Kaha
He ngaru miihini te oro e horapa ana i roto i tētahi reo pērā i te hau, te wai, ngā mea totoka rānei. He ariā nui te kaha o te oro me ngā taumata kaha o te oro i roto i te ahupūngao e āwhina ana i a tātou ki te mārama ki te āhua o tā tātou whakarongo me te kite i te oro. Ka whakamāramahia e tēnei tuhinga te ariā taketake o te kaha o te oro, ngā tātai e pā ana ki te kaha me ngā taumata kaha o te oro, me ō rātou whakamahinga i roto i te oranga o ia rā.
Ariā Taketake o te Kaha o te Oro
Ko te kaha oro e pā ana ki te nui o te pūngao e haria ana e te ngaru oro mō ia wae horahanga mō ia wae wā. Mā te pāngarau, ka taea te whakaatu i te kaha oro (I) penei:
\[ I = \frac{P}{A} \]
Kei hea:
– Ko I te kaha oro (i roto i ngā watts ia mita tapawha, W/m²).
– Ko P te mana, te pūngao rānei mō ia wā ka tukuna e te pūtake oro (i roto i ngā watts, W).
– Ko A te horahanga e haerehia ana e te ngaru oro (i roto i ngā mita pūrua, m²).
Ko te kaha o te oro e whakaatu ana i te kaha, te ngoikore rānei o te tangi e rangona ana i tētahi tawhiti mai i te pūtake oro.
Taumata Kaha o te Oro (Taumata Kaha)
Ko te taumata kaha oro, ko te taumata kaha oro rānei, he inenga logarithm o te kaha oro e pā ana ki te kaha tohutoro e whakaaetia whānuitia ana. Ko te waeine e whakamahia ana hei ine i te taumata kaha oro ko te decibel (dB). Ko te tātai mō te tatau i te taumata kaha oro (L) ko:
\[ L = 10 \log_{10} \left( \frac{I}{I_0} \right) \]
Kei hea:
– Ko L te taumata kaha oro (i roto i ngā desipere, dB).
– Ko I te kaha oro i inehia (i roto i te W/m²).
– Ko I₀ te kaha tohutoro, ko te tikanga \( 10^{-12} \) W/m², koinei te paepae whakarongo tangata.
Tauira o te Tātaitanga o te Kaha o te Oro me te Taumata Kaha
Hei whakamārama i tēnei ariā, me titiro tātou ki ētahi tauira o te tatau i te kaha o te oro me ngā taumata kaha.
Tauira 1: Te Tatau i te Kaha o te Oro
Me kī, e 0,01 W te kaha e tukuna ana e te pūtake oro, ā, ka tohatohahia taua kaha ki ngā taha katoa. Tātaihia te kaha o te oro i te tawhiti o te 2 mita mai i te pūtake oro.
Otinga:
Ko te horahanga o te mata o tētahi porowhita he 2 mita te whānui:
\[ A = 4 \pi r^2 \]
\[ A = 4 \pi (2)^2 \]
\[ A = 16 \pi \text{ m}^2 \]
Ka taea te tatau i te kaha o te oro mā te whakamahi i te tātai:
\[ I = \frac{P}{A} \]
\[ I = \frac{0,01 \text{ W}}{16 \pi \text{ m}^2} \]
\[ I \tata \frac{0,01}{50,24} \text{ W/m}^2 \]
\[ I \tata ki te 1,99 \times 10^{-4} \text{ W/m}^2 \]
Tauira 2: Te Tātai i te Taumata Kaha o te Oro
Mena ko te kaha o te oro i tētahi tawhiti mai i te pūtake he \( 1,99 \times 10^{-4} \) W/m², tatauhia te taumata kaha o te oro i roto i ngā tesipere.
Otinga:
Mā te whakamahi i te tātai taumata kaha oro:
\[ L = 10 \log_{10} \left( \frac{I}{I_0} \right) \]
\[ L = 10 \log_{10} \left( \frac{1,99 \times 10^{-4}}{10^{-12}} \right) \]
\[ L = 10 \log_{10} \left( 1,99 \times 10^8 \right) \]
\[ L \tata ki te 10 \log_{10} (1,99 \whakareatia ki te 10^8) \]
\[ L \tata ki te 10 \left( \log_{10} (1,99) + \log_{10} (10^8) \right) \]
\[ L \tata ki te 10 \maui( 0,3 + 8 \matau) \]
\[ L \tata ki te 10 \whakareatia ki te 8,3 \]
\[ L \tata ki te 83 \kuputuhi{ dB} \]
Ngā Take e Pā Ana ki te Kaha o te Oro
He maha ngā āhuatanga ka pā ki te kaha o te oro, tae atu ki:
1. Te Tawhiti mai i te Pūtake Oro: Ka heke te kaha o te oro i te tawhiti haere mai i te pūtake. Nā te horapa o te pūngao ki tētahi wāhi whānui ake tēnei.
2. Waenga Whakatō: Ka pāngia te tere me te horapa o te oro e te waenga whakatō. Hei tauira, ka tere ake te haere o te oro i roto i te wai i te haere i roto i te hau.
3. Ngā Āhuatanga o ngā Pūtake Oro: Ka pā te kaha o te pūtake oro me te auau o ngā ngaru oro ki te kaha e whakaputaina ana.
Te Kaha o te Oro me te Taumata Kaha o te Whakamahinga
E whakamahia ana ngā ariā o te kaha me ngā taumata kaha oro i roto i ngā mahi maha, pērā i:
1. Hauora me te Haumaru Mahi: He mea nui te ine i ngā taumata kaha o te haruru hei whakahaere i te haruru i te wāhi mahi, hei ārai hoki i te ngaronga o te rongo nā te nui rawa o te haruru.
2. Te Oro o te Rūma: Ka whai whakaaro te hoahoa oro o ngā rūma, pērā i ngā whare whakatangitangi me ngā whare tuhi oro, ki te kaha o te oro hei whakarite i te kounga oro tino pai.
3. Ngā Pūnaha Whakaoho: I roto i ngā pūnaha oro me ngā pūnaha whakaoho, ka whakamahia te kaha o te oro hei whakahaere i te rōrahi me te kounga o te oro.
4. Tātaritanga Hauora: I roto i te ao hauora, ka whakamahia e te ultrasound ngā ngaru oro kaha-teitei hei whakaputa whakaahua o ngā kiko i roto i te tinana.
Te Tātaitanga Taumata Kaha mō ngā Pūtake Oro Maha
Ina mahi tahi ngā pūtake oro maha i te wā kotahi, ko te kaha katoa ko te tapeke o ngā kaha o ia pūtake. Heoi, hei tatau i te taumata kaha katoa, kāore e tāpiri noa i ngā uara teitipere. Engari, me hoki tātou ki te kaha rārangi, tāpirihia ngā kaha, kātahi ka huri anō ki te teitipere.
Me kī e rua ngā pūtake oro, ko te kaha o te oro he 70 dB me te 75 dB. Tātaihia te kaha katoa.
Otinga:
Tahurihia ngā taumata kaha ki te kaha rārangi:
\[ I_1 = I_0 \whakareatia ki te 10^{L_1/10} \]
\[ I_1 = 10^{-12} \whakareatia ki te 10^{70/10} \]
\[ I_1 = 10^{-12} \whakareatia ki te 10^7 \]
\[ I_1 = 10^{-5} \text{ W/m}^2 \]
\[ I_2 = I_0 \whakareatia ki te 10^{L_2/10} \]
\[ I_2 = 10^{-12} \whakareatia ki te 10^{75/10} \]
\[ I_2 = 10^{-12} \whakareatia ki te 10^{7,5} \]
\[ I_2 = 10^{-12} \times 3,16 \times 10^7 \]
\[ I_2 = 3,16 \times 10^{-5} \text{ W/m}^2 \]
Tāpirihia ngā kaha:
\[ I_{\text{tapeke}} = I_1 + I_2 \]
\[ I_{\text{tapeke}} = 10^{-5} + 3,16 \times 10^{-5} \]
\[ I_{\text{tapeke}} = 4,16 \times 10^{-5} \text{ W/m}^2 \]
Tahurihia ki ngā tekipere:
\[ L_{\text{tapeke}} = 10 \log_{10} \left( \frac{I_{\text{tapeke}}}{I_0} \right) \]
\[ L_{\text{total}} = 10 \log_{10} \left( \frac{4,16 \times 10^{-5}}{10^{-12}} \right) \]
\[ L_{\text{total}} = 10 \log_{10} (4,16 \times 10^7) \]
\[ L_{\text{total}} \approx 10 (\log_{10} 4,16 + \log_{10} 10^7) \]
\[ L_{\kuputuhi{katoa}} \tata ki te 10 (0,62 + 7) \]
\[ L_{\kuputuhi{katoa}} \tata ki te 76,2 \kuputuhi{ dB} \]
Whakamutunga
He ariā nui te kaha o te oro me ngā taumata kaha oro i roto i te ahupūngao me te hangarau, e āwhina ana i a tātou ki te mārama me te ine i te oro i roto i ngā horopaki rerekē. Mā te whakamahi i ngā tātai e tika ana, ka taea e tātou te tatau i te nui o te oro me te whakahaere i ngā pānga o te haruru i roto i te oranga o ia rā. He whai hua tēnei mōhiotanga i roto i te whānuitanga o ngā tono, mai i te hauora me te haumaru mahi ki te hoahoa oro me te tātaritanga hauora. Mā te mārama ki te taunekeneke o te oro ki te taiao me te pehea e ine ai tātou ka taea e tātou te waihanga i ngā taiao whakamarie me te haumaru mō te katoa.
