scholarly journals Estimating the Optimal Velocity Measurement Time in Rivers’ Flow Measurements: An Uncertainty Approach

Water ◽  
2018 ◽  
Vol 10 (8) ◽  
pp. 1010
Author(s):  
Robert Clasing ◽  
Enrique Muñoz
Keyword(s):  
Stability Criterion ◽  
Velocity Measurement ◽  
Measurement Time ◽  
Optimal Time ◽  
Optimal Point ◽  
Flow Measurements ◽  
Central Chile ◽  
Optimal Velocity ◽  
South Central ◽  
Point Velocity

The gauging process can be very extensive and time-consuming due to the procedures involved. Since velocity measurement time (VMT) is one of the main variables that would allow gauging times to be reduced, this study seeks to determine the optimal point VMT and, thereby, reduce the overall gauging time. An uncertainty approach based on the USGS area-velocity method and the GLUE methodology applied to eight gauging samples taken in shallow rivers located in South-central Chile was used. The average point velocity was calculated as the average of 1 to 70 randomly selected instant velocity samples (taken every one second). The time at which the uncertainty bands reached a stability criterion (according to both width and slope stability) was considered to be the optimum VMT since the variations were negligible and it does not further contribute to a less uncertain solution. Based on the results, it is concluded that the optimum point VMT is 17 s. Therefore, a point velocity measurement of 20 s is recommended as the optimal time for gauging in shallow rivers.

scholarly journals Cardiorespiratory Fitness: Reference on the Six-Minute Walk Test and Oxygen Consumption in Adolescents from South-Central Chile

2021 ◽  
Vol 18 (5) ◽  
pp. 2474
Author(s):  
Jaime Vásquez-Gómez ◽  
Nelson Gatica Salas ◽  
Pedro Jiménez Villarroel ◽  
Luis Rojas-Araya ◽  
Cesar Faundez-Casanova ◽  
...  
Keyword(s):  
Cardiorespiratory Fitness ◽  
Reference Values ◽  
Estimation Error ◽  
Walk Test ◽  
Central Chile ◽  
Six Minute Walk Test ◽  
Body Adiposity ◽  
South Central ◽  
Males And Females ◽  
Minute Walk

Cardiorespiratory fitness (CRF) provides oxygen to the exercising muscles and is related to body adiposity, with cardiometabolic variables. The aim was to develop reference values and a predictive model of CRF in Chilean adolescents. A total of 741 adolescents of both genders (15.7 years old) participated in a basic anthropometry, performance in the six-minute walk test (SMWT), and in Course Navette was measured. Percentiles were determined for the SMWT, for the V̇O2max, and an equation was developed to estimate it. The validity of the equation was checked using distribution assumptions and the Bland–Altman diagram. The STATA v.14 program was used (p < 0.05). The 50th percentile values for males and females in the SMWT and in the V̇O2max of Course Navette were, respectively, from 607 to 690 and from 630 to 641 m, and from 43.9 to 45 and from 37.5 to 31.5 mlO2·kg·min−1, for the range of 13 to 17 years. For its part, the model to predict V̇O2max incorporated gender, heart rate, height, waist-to-height ratio (WHR), and distance in the SMWT (R2 = 0.62; estimation error = 0.38 LO2·min−1; p <0.001). Reference values can guide physical fitness in Chilean adolescents, and V̇O2max was possible to predict from morphofunctional variables.

Population Abundances, Tidal Movement, Burrowing Ability and Oxygen Uptake of Emerita analoga (Stimpson) (Crustacea, Anomura) on a Sandy Beach of South-Central Chile

2004 ◽  
Vol 25 (1) ◽  
pp. 71-89 ◽  
Author(s):  
Mariano Lastra ◽  
Eduardo Jaramillo ◽  
Jesus Lopez ◽  
Heraldo Contreras ◽  
Cristian Duarte ◽  
...  
Keyword(s):  
Oxygen Uptake ◽  
Sandy Beach ◽  
Central Chile ◽  
South Central ◽  
Emerita Analoga ◽  
Tidal Movement

Alteration patterns of chromian spinels from La Cabaña peridotite, south-central Chile

2014 ◽  
Vol 108 (6) ◽  
pp. 819-836 ◽  
Author(s):  
Fernando Barra ◽  
Fernando Gervilla ◽  
Elkin Hernández ◽  
Martin Reich ◽  
José Alberto Padrón-Navarta ◽  
...  
Keyword(s):  
Central Chile ◽  
South Central
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