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In environmental chemistry, the chemical oxygen demand (COD) is an indicative measure of the amount of oxygen that can be consumed by reactions in a measured solution. It is commonly expressed in mass of oxygen consumed over volume of solution, which in SI units is milligrams per liter ( mg / L ).
Oxygen transmission rate (OTR) is the measurement of the amount of oxygen gas that passes through a substance over a given period. It is mostly carried out on non-porous materials, where the mode of transport is diffusion, but there are a growing number of applications where the transmission rate also depends on flow through apertures of some description.
Most humans can function at rest with an oxygen level of 15% at one atmosphere pressure; [1] a fuel such as methane is combustable down to 12% oxygen in nitrogen. A small room of 10 meter 3 has 2.08 meter 3 (2080 liters) or 2.99 kg of oxygen which would occupy 2.62 liters if it was liquid. [2]
To create the solution, 11.6 g NaCl is placed in a volumetric flask, dissolved in some water, then followed by the addition of more water until the total volume reaches 100 mL. The density of water is approximately 1000 g/L and its molar mass is 18.02 g/mol (or 1/18.02 = 0.055 mol/g). Therefore, the molar concentration of water is c(H 2 O ...
Most PVC sheets for pharmaceutical blisters are 250 μm (0.25 mm) in thickness. Typical values for the Water Vapor Transmission Rate (WVTR or MVTR) of a 250 μm PVC film are around 3.0 g/m 2 per day measured at 38 °C (100 °F) and 90% RH and the Oxygen Transmission Rate (OTR) is around 20 mL/m per day. In order to overcome the lack of barrier ...
Hypoxemia is usually defined in terms of reduced partial pressure of oxygen (mm Hg) in arterial blood, but also in terms of reduced content of oxygen (ml oxygen per dl blood) or percentage saturation of hemoglobin (the oxygen-binding protein within red blood cells) with oxygen, which is either found singly or in combination. [2] [5]
Natural air includes 21% oxygen, which is equivalent to F I O 2 of 0.21. Oxygen-enriched air has a higher F I O 2 than 0.21; up to 1.00 which means 100% oxygen. F I O 2 is typically maintained below 0.5 even with mechanical ventilation, to avoid oxygen toxicity, [2] but there are applications when up to 100% is routinely used.
The model describes how dissolved oxygen (DO) decreases in a river or stream along a certain distance by degradation of biochemical oxygen demand (BOD). The equation was derived by H. W. Streeter, a sanitary engineer, and Earle B. Phelps , a consultant for the U.S. Public Health Service , in 1925, based on field data from the Ohio River .