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Etalonarea termometrelor din sticlă cu mercur - temperature.ro

Etalonarea termometrelor din sticlă cu mercur - temperature.ro

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egal <st<strong>ro</strong>ng>cu</st<strong>ro</strong>ng> 1, contributia la uc(?C) a incertitu<st<strong>ro</strong>ng>din</st<strong>ro</strong>ng>ii standard u(dCstab) va fi egala <st<strong>ro</strong>ng>cu</st<strong>ro</strong>ng> astab<br />

k/(2v3).<br />

Marimile de intrare CLab i (i = 2, 3 ..., 7) si CLR sunt partial corelate, toate<br />

etaloanele folosite fiind trasabile la etalonul national de temperatura. Pentru a nu<br />

complica prea mult cal<st<strong>ro</strong>ng>cu</st<strong>ro</strong>ng>lele, vom presupune, totusi, ca marimile CLab i si CLR sunt<br />

necorelate. Aplicând legea de p<strong>ro</strong>pagare a incertitu<st<strong>ro</strong>ng>din</st<strong>ro</strong>ng>ii, incertitu<st<strong>ro</strong>ng>din</st<strong>ro</strong>ng>ea standard compusa<br />

asociata abaterii ?C s-a cal<st<strong>ro</strong>ng>cu</st<strong>ro</strong>ng>lata astfel:<br />

uc (?C) = [u 2 ( CLab i) + u 2 (CLR) + u 2 (dCstab)] 1/2 .<br />

În Tabelele 5, 7, 9, 11, 13 si 15 sunt înscrise incertitu<st<strong>ro</strong>ng>din</st<strong>ro</strong>ng>ea standard compusa si<br />

incertitu<st<strong>ro</strong>ng>din</st<strong>ro</strong>ng>ea extinsa (pentru k = 2) asociate abaterilor ?C.<br />

La cal<st<strong>ro</strong>ng>cu</st<strong>ro</strong>ng>lul incertitu<st<strong>ro</strong>ng>din</st<strong>ro</strong>ng>ii asociate diferentelor <st<strong>ro</strong>ng>din</st<strong>ro</strong>ng>tre rezultatele obtinute de oricare 2<br />

laboratoare participante la comparare (Tabelele 17-31) s-a folosit functia de modelare<br />

?C = CLab i – CLab j . (2)<br />

Presupunând ca marimile de intrare sunt necorelate si aplicând legea de<br />

p<strong>ro</strong>pagare a incertitu<st<strong>ro</strong>ng>din</st<strong>ro</strong>ng>ii, incertitu<st<strong>ro</strong>ng>din</st<strong>ro</strong>ng>ea standard compusa asociata diferentei ?C a fost<br />

cal<st<strong>ro</strong>ng>cu</st<strong>ro</strong>ng>lata astfel:<br />

uc (?C) = [u 2 ( CLab i) + u 2 (CLab j)] 1/2 .<br />

3.2 Prezentarea rezultatelor masurarilor<br />

În Figura 1 sunt prezentate comparativ corectiile determinate de Laboratorul de referinta<br />

si de cele 6 laboratoare participante pre<st<strong>ro</strong>ng>cu</st<strong>ro</strong>ng>m si incertitu<st<strong>ro</strong>ng>din</st<strong>ro</strong>ng>ile extinse U (k = 2) asociate<br />

acestor corectii, pentru fiecare punct de etalonare.<br />

12

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