This paper describes construction and characterization of a dew/frost -point generator developed at national institute for standards. It is intended to operate in the range from -50 ℃to 0 ℃. The air flows through a ...This paper describes construction and characterization of a dew/frost -point generator developed at national institute for standards. It is intended to operate in the range from -50 ℃to 0 ℃. The air flows through a saturator controlled by a regulated flow meter. The reference dew/frost -point temperature was measured by standard platinum resistance thermometer （SPRT） connected to a resistance bridge. A comparative study between the saturator temperature of the new generator measured by SPRT and the dew/frost-point temperature of a calibrated chilled-mirror hygrometer was conducted. It helped to determine the uncertainty of saturator; this uncertainty was found to be between ±0.06℃ to -4- 0.15℃ at confidence limit of 95%.Several experiments were carried out in the mentioned range. Obtained results gave the confidence that NIS generator could be used as a primary humid air generator.展开更多
The purpose of this paper is to apply ＂LARS-WG （Long Ashton Research Station--Weather Generator）＂ model to simulate the climate change scenarios for Phu Luong watershed in northem Viet Nam. Results indicated that ...The purpose of this paper is to apply ＂LARS-WG （Long Ashton Research Station--Weather Generator）＂ model to simulate the climate change scenarios for Phu Luong watershed in northem Viet Nam. Results indicated that LARS-WG adequately predicted precipitation and temperature with R2 = 0.80 and 0.73, respectively. Likewise, p-value of F test = 0.062 and p-value of t test = 0.885 for precipitation, meanwhile, for temperature are 0.092 and 0.564 at 0.05 level of significance, respectively. Moreover, results also stated that mean annual precipitation increases 1.62%, 2.17% and 3.96% and mean annual temperature increases 0.6 ℃, 0.8 ℃ and 1.05 ℃ in 2020, 2030 and 2040, respectively, with respect to those from baseline periods. This study also showed that LARS-WG model was used successfully for Viet Nam＇s watershed conditions.展开更多
A new humidity calibration facility using a 2-T （two-temperature）, constant pressure principle for generating gas of known humidity has been developed at NIS for primary realization of relative humidity scale in the...A new humidity calibration facility using a 2-T （two-temperature）, constant pressure principle for generating gas of known humidity has been developed at NIS for primary realization of relative humidity scale in the range from 13% to 98% for calibrating and testing hygrometers to improve the uncertainty. This paper reports the construction of the 2-T humidity generator describing its saturator and the test chamber system. Results of the efficiency tests of its saturator showed satisfactory generation performance for a primary realization of relative humidity scale. The expanded uncertainty of the relative humidity with a coverage factor k = 2 was found to be from ± 0.25 % to ± 0.67%.展开更多
文摘This paper describes construction and characterization of a dew/frost -point generator developed at national institute for standards. It is intended to operate in the range from -50 ℃to 0 ℃. The air flows through a saturator controlled by a regulated flow meter. The reference dew/frost -point temperature was measured by standard platinum resistance thermometer （SPRT） connected to a resistance bridge. A comparative study between the saturator temperature of the new generator measured by SPRT and the dew/frost-point temperature of a calibrated chilled-mirror hygrometer was conducted. It helped to determine the uncertainty of saturator; this uncertainty was found to be between ±0.06℃ to -4- 0.15℃ at confidence limit of 95%.Several experiments were carried out in the mentioned range. Obtained results gave the confidence that NIS generator could be used as a primary humid air generator.
文摘The purpose of this paper is to apply ＂LARS-WG （Long Ashton Research Station--Weather Generator）＂ model to simulate the climate change scenarios for Phu Luong watershed in northem Viet Nam. Results indicated that LARS-WG adequately predicted precipitation and temperature with R2 = 0.80 and 0.73, respectively. Likewise, p-value of F test = 0.062 and p-value of t test = 0.885 for precipitation, meanwhile, for temperature are 0.092 and 0.564 at 0.05 level of significance, respectively. Moreover, results also stated that mean annual precipitation increases 1.62%, 2.17% and 3.96% and mean annual temperature increases 0.6 ℃, 0.8 ℃ and 1.05 ℃ in 2020, 2030 and 2040, respectively, with respect to those from baseline periods. This study also showed that LARS-WG model was used successfully for Viet Nam＇s watershed conditions.
文摘A new humidity calibration facility using a 2-T （two-temperature）, constant pressure principle for generating gas of known humidity has been developed at NIS for primary realization of relative humidity scale in the range from 13% to 98% for calibrating and testing hygrometers to improve the uncertainty. This paper reports the construction of the 2-T humidity generator describing its saturator and the test chamber system. Results of the efficiency tests of its saturator showed satisfactory generation performance for a primary realization of relative humidity scale. The expanded uncertainty of the relative humidity with a coverage factor k = 2 was found to be from ± 0.25 % to ± 0.67%.
