No compartimento particulado, essa relacao foi mais acentuada, principalmente no LVTA, pois, conforme BAYER et al.
pH [Al.sup.+3] [Al.sup.+3] textural (cm) (Ca [mmol.sub.c] [dm.sup.-3] [Cl.sub.2]) LVTM ([dagger]) 0-20 5,2 50 2,0 LVTA ([dagger] 0-20 5,3 65 1,5 [dagger]) Classe [Ca.sup.+2] [Mg.sup.+2] [K.sup.+] P* textural [mmol.sub.c] [dm.sup.-3] mg [dm.sup.-3] LVTM ([dagger]) 31,0 20,0 3,0 1,4 LVTA ([dagger] 30,0 15,0 4,0 1,9 [dagger]) Classe C Areia Silte Argila textural g [kg.sup.-1] LVTM ([dagger]) 14,0 667 101 232 LVTA ([dagger] 20,0 507,5 91,5 401 [dagger]) ([dagger]) Latossolo Vermelho Distrofico tipico, com classe textural franco argilo arenosa ; ([dagger][dagger]) Latossolo Vermelho Distrofico tipico, com classe textural franco argilosa ; ([dagger][dagger][dagger]) [Mehlich.sup.-1].
The difference between the standard deviation measured by each of the anemometers and the mean standard deviation (of the four LVTAs) was then calculated.
All important error sources related to measurement with LVTAs were identified as follows:
The error due to calibration reference remains constant and dominant with regard to the mean speed for all four LVTAs, while the uncertainty due to the remaining error sources increase with the increase of the mean speed (except for the uncertainty due to conversion and reproducibility).
1998b), new updated requirements for the characteristics of LVTAs were developed and suggested for inclusion in future standards.
The defined uncertainties are slightly higher than the uncertainty achieved with the tested anemometers, which, as already discussed, comply with the strict but achievable in practice requirements for the characteristics of LVTAs specified in Table 1.
This is important information, especially when measurements with LVTAs are used for validation of CFD predictions.
Therefore, the maximum absolute expanded uncertainty in determination of DR, based on measurements with LVTAs that comply with the requirement specified in Table 1, can be defined as [+ or -]5% (see Figure 11).
The static calibration of LVTAs is the most important factor for accurate measurement of mean speed indoors, while, with regard to the standard deviation of speed, the errors due to directional sensitivity, dynamic response, calibration reference, and air temperature fluctuations are substantial.
Requirements for LVTAs that will decrease the uncertainty of low-velocity measurements and improve the accuracy of indoor environment assessment are suggested for inclusion in future standards.
The minimum absolute uncertainty in mean speed measurements with LVTAs is defined for anemometers that comply with the suggested requirements.