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Ventilating Confined Spaces
Published in John F. Rekus, Complete Confined Spaces Handbook, 2018
Next, convert the cross-sectional area to square feet. Since there are 144 square inches in a square foot, the cross-sectional area can be converted to square feet by dividing it by 144, resulting in 0.349 square feet.
Process/Pressure Measuring Instruments
Published in Norman A. Anderson, Instrumentation for Process Measurement and Control, 2017
Pressure is force divided by the area over which it is applied. Pressure is often defined in terms of “head.” For example, assume that we have a water column 1 foot square and 23 feet tall. We want to find the pressure in the bottom of the column. The weight of the column may be calculated by first finding the volume of water. This is the area of the base multiplied by height, or 1 times 23 equals 23 cubic feet. Water weighs 62.43 pounds per cubic foot. So the weight of 23 cubic feet will be 23 times 62.43, or 1,435.89 pounds. The area of the base is 1 square foot, or 12 inches times 12 inches, or 144 square inches. The pressure equals 1,434.89 divided by 144 equals 9.9715, or approximately 10 pounds per square inch. In practice, we find that only the height of the water counts. It may be present in a small pipe or beneath the surface of a pond. In any case, at a depth of 23 feet, the pressure will amount to approximately 10 pounds per square inch. If in your home the water pressure is 50 pounds per square inch and the system uses a gravity feed, the water tank, or reservoir, holds the water at a height of 50 divided by 10, or 5 times 23 equals 115 feet above the point where the pressure measurement is made. Head and pressure, then, may mean the same thing. We must be able to convert from one to the other. You may encounter reference to inches of mercury for pressure measurement. Mercury is 13.596 times as heavy as an equal volume of water. Therefore, a head of mercury exerts a pressure 13.596 times greater than an equivalent head of water. Because it is hazardous, mercury no longer is used commonly in manometers.
Influence of repeated contacts on the transfer of elemental metallic lead between compartments in an integrated conceptual model for dermal exposure assessment
Published in Journal of Toxicology and Environmental Health, Part A, 2022
J. Sahmel, S. Arnold, G. Ramachandran
At the start of data collection, each volunteer was asked to wash their hands thoroughly with the Pb decontamination soap and water and to avoid contact with any other surfaces. The thumb and first two fingers of the volunteer’s dominant hand were then taped at the crease of the last distal digit to visually control the skin surface area for both study objects and wipe sampling. An image of the hands was collected using a photocopier set to 100% image size to ensure consistent comparative images for measurement purposes. After the tape was applied for purposes of measuring, the two-dimensional surface area of the skin was used in the study. Images were analyzed by calculating the pixels per square inch of the identified skin surface area (www.adobe.com; www.bluebeam.com). After imaging, two serial background wipes were collected for the two-dimensional surface of the three fingertips (Figure 4).
Determination of safe mud weight window based on well logging data using artificial intelligence
Published in Geosystem Engineering, 2019
Javad Zahiri, Mohammad Abdideh, Elias Ghaleh Golab
In vertical stress, ρ is rock density (as per density log), z is depth, and g is gravitational acceleration on the ground (9.8 m/s2). These stress values are obtained in pounds per square inch (psi) or Giga Pascal (GPa). When it comes to horizontal stresses, however, we will encounter larger numbers of the parameter. In δh, v is Poisson’s ratio, α is Biot factor, Pp is pore pressure, E is the modulus of elasticity (static), εy is strain along the y-axis, and εx is the strain along the x-axis. Biot factor represents transmissibility of the rock and its value ranges between 0 and 1. For a porous and permeable reservoir rock, the value of Biot factor is 1, while that of a non-porous rock is 0. Meanwhile, accurate value of this parameter is calculable from the log. In the oil industry, in order to calculate the values of εx and εy, a modern log called Dipole Sonic Image log is used. Due to limited access to cores and rock mechanic laboratory and relying on the experienced tests on similar reservoir rocks, a Biot factor of 1, εx of 1.5, and εy of 0.5 were considered.
Sequential Minimum Risk Point Estimation of the Parameters of an Inverse Gaussian Distribution
Published in American Journal of Mathematical and Management Sciences, 2020
Ajit Chaturvedi, Sudeep R. Bapat, Neeraj Joshi
We now demonstrate the applicability of our proposed purely sequential procedure (7) in Table 3 using a real data set from reliability studies. This data set was reported by Birnbaum and Saunders (1958, 1969), and corresponds to the fatigue life, measured in cycles of 101 aluminum coupons of type 6061-T6. These aluminum sheets were cut parallel to the direction of rolling and oscillating at 18 cycles per second. These were then exposed to pressure at a stress level of 31,000 psi (pounds per square inch). All coupons were tested until they failed.