Measurement of fluid flow in closed conduits. Weighing method

In the context of the needs of the leading sectors of the world economy, the current state of metrological support for measuring units of mass and volume of a liquid in a flow, mass and volume flow rates of a liquid in the range of micro-flow rates of 10–5–103 ml/min is considered. Based on the results of the analytical review, the main metrological and operating characteristics of national standards are presented. The basic principles of generating a fluid flow in national gravimetric and volumetric standards when measuring the mass and volume of a fluid by the dynamic weighing method have been determined. Constructive solutions and principles of operation of key modules of national standards are considered. Methods for filling a liquid into a storage tank and designs of storage tanks are determined, taking into account the minimization of the effect of liquid evaporation, the influence of capillary force and buoyancy. The main sources of uncertainty in measuring the mass and volume of a liquid by the dynamic weighing method and methods for minimizing these uncertainties are considered. A modified model of dynamic measurement of liquid mass flow rate is proposed, taking into account the main sources of uncertainty. A comparative assessment of the influence of sources of uncertainty on the metrological characteristics of national standards is presented.

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Measurement of fluid flow in closed conduits. Weighing method

10.3403/00089616 ◽

1981 ◽

Keyword(s):

Fluid Flow ◽

Weighing Method

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The Relationship Between Antioxidant Nutrient Intake and Cataracts in Older People

International Journal for Vitamin and Nutrition Research ◽

10.1024/0300-9831.76.6.359 ◽

2006 ◽

Vol 76 (6) ◽

pp. 359-366 ◽

Cited By ~ 11

Author(s):

Rodríguez-Rodríguez ◽

Ortega ◽

López-Sobaler ◽

Aparicio ◽

Bermejo ◽

...

Keyword(s):

Vitamin C ◽

Older People ◽

Dietary Intake ◽

Protective Effect ◽

Elderly People ◽

Nutrient Intake ◽

Institutionalized Elderly ◽

Weighing Method ◽

The Relationship

This study investigated the relationship between the intake of antioxidant nutrients and the suffering of cataracts in 177 institutionalized elderly people (61 men and 116 women) aged ≥ 65 years. Dietary intake was monitored for 7 consecutive days using a "precise individual weighing" method. Subjects, who during their earlier years were exposed by their work to sunlight, had a greater risk of suffering cataracts (OR = 3.2; Cl: 1.1–9.3, P < 0.05) than those who worked indoors. A relationship was found between increased vitamin C intake and a reduced prevalence of cataracts (i.e., when comparing those above P95 for vitamin C intake with those below P5; (OR = 0.08; Cl: 0.01–0.75, P 0.05). Among subjects with cataracts, 12.1% had vitamin C intakes of < 61 mg/day (P10) and only 2.2% had intakes of > 183 mg/day (P95) (p < 0.01). Subjects who consumed > 3290 μg/day (P95) of lutein were less likely to have cataracts (OR = 0.086; Cl: 0.007–1.084; p < 0.05) than those whose consumption was < 256 μg/day (P5). In men, high intakes of zeaxanthin seemed to provide a protective effect against the problem (OR = 0.96; Cl: 0.91–0.99; p < 0.05). The results suggest an association exists between exposure to sunlight and the development of cataracts, and that vitamin C, lutein, and zeaxanthin offer some protection against this disorder.

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