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Environmental Conditions and Patient Preparation
Published in James Stewart Campbell, M. Nathaniel Mead, Human Medical Thermography, 2023
James Stewart Campbell, M. Nathaniel Mead
Although the size of the room does not alter the quality of thermal images, very large rooms can be drafty and tend to be less comfortable for the patient.3 Ambient temperatures can be difficult to maintain in large spaces. Airflow in the area where the subject is positioned should be barely discernible, with airspeed 0.2 meters per second (0.66 fps) or less.4 The patient area should be carpeted in order to insulate the patient from the cold floor. In medical settings where carpeting is not allowed, an impervious, washable insulated mat can be used.
Nature of Flow of a Liquid
Published in Wilmer W Nichols, Michael F O'Rourke, Elazer R Edelman, Charalambos Vlachopoulos, McDonald's Blood Flow in Arteries, 2022
It can thus be seen that if the velocity of a liquid is increased in a horizontal tube, the lateral pressure must be correspondingly decreased. This effect is particularly apparent at a constriction in a vessel (point D) and is applied in devices such as the Pitot tube and orifice (or Venturi) meters that have been used for measuring blood flow. The Pitot-static system is also used in aviation to determine an aircraft’s airspeed. Bernoulli’s equation can also be applied to unsteady flows. The expression has been derived for the general case by considering the fluctuations of flow as variables in respect of position along a streamline in respect to time (Kaufmann, 1963), but the problem can be approached more generally through the Navier–Stokes equations. The unsteady Bernoulli equation accurately predicted the measured pressure gradient across a stenotic aortic valve in dogs (Bermejo et al., 2002). The application of the Bernoulli formulation in humans results in a clinically significant overestimation of peak pressure drops because of approximation of blood flow as a single streamline. A corrected formulation that accounts for the cross-sectional profile of the blood flow has been proposed and adapted to both cardiovascular magnetic resonance and echocardio-graphic data (Donti et al., 2017).
Mechanics of Cycling
Published in Christopher L. Vaughan, Biomechanics of Sport, 2020
Dirk J. Pons, Christopher L. Vaughan
where F is in Newtons, M is mass in kilograms, v is the air speed in meters per second, A is body surface area in square meters, p is air pressure in torr, v is air speed in meters per second, and T is temperature in degrees Kelvin. di Prampero et al.19 substituted values for a cyclist on a conventional racing bicycle, in the fully crouched position, and obtained
Effects of clothing size and air ventilation rate on cooling performance of air ventilation clothing in a warm condition
Published in International Journal of Occupational Safety and Ergonomics, 2022
Jie Yang, Faming Wang, Guowen Song, Rui Li, Uday Raj
Clothing size L is bulkier due to more air storage in the microclimate during the initial transient phenomenon after switching on the ventilation fans. Due to this bulkiness, the air gap in the microclimate is higher in the case of size L. For a specific air ventilation rate, the larger air gap between clothing and the body results in a lower air speed in the clothing microclimate. Lower air speed results in proper contact of dry ambient air with the manikin body and, hence, air gets sufficient time to absorb the body heat. Probably, this is the reason why higher body heat losses were observed in clothing size L as compared to other two clothing sizes at both levels of ventilation rates. In clothing size L, the second phenomenon explained earlier dominates over the first phenomenon as overall higher body heat loss was observed. If the air gap width is smaller, relatively higher air speed can be obtained in the microclimate at a given ventilation rate. As already mentioned, due to the two phenomena, a higher air speed causes higher body heat loss (due to a higher Reynolds number and heat transfer coefficient) as well as lower body heat loss (due to improper and insufficient contact of air with the body) [31].
Quantifying cellular protrusion in alginate capsules with covalently crosslinked shells
Published in Journal of Microencapsulation, 2019
Mitchell A. Johnson, Rachelle Kleinberger, Ali Abu Helal, Nicole Latchminarine, Ahmed Ayyash, Shanna Shi, Nicholas A. D. Burke, Alison C. Holloway, Harald D. H. Stöver
For the current study, we prepared capsules of about 500 micrometer diameters, arguably the most common size. We used a vertical syringe holder machined from a block of graphite-loaded Delrin (Supporting Information Scheme S1), designed to accommodate a syringe equipped with needle gauges above 20 with a coaxial air flow. A series of experiments were carried out to examine the effects of annular airspeed on both bead size and on bead quality as assessed by the percentage of non-spherical capsules. Figure S1 (Supporting Information) shows that the average diameter and size distribution of the Ca-alginate capsules decreased, while the proportion of capsules with nonspherical shapes increased, with increasing annular air speed. Nonspherical capsules typically had tails that may increase immune responses. For all subsequent experiments, an air speed of about 8 m/s was chosen to form about 500 micrometer capsules with very few non-spherical capsules. Liquid flow rate had little effect on capsule diameter or quality (results not shown), and was kept constant at 8 ml/h.
Cause analysis of unsafe acts of pilots in general aviation accidents in China with a focus on management and organizational factors
Published in International Journal of Occupational Safety and Ergonomics, 2023
Qian Ma, Guojun Wang, Sven Buyle, Xuan Jiang
Skill-based errors are the failures of highly practised behaviour that occur with little or no conscious thought. Skill-based errors frequently appear as a failure to see and avoid, a breakdown in visual scan and inadvertent use of aircraft. Decision errors are best described as ‘honest mistakes’ and often occur in situations where pilots do not have the appropriate knowledge or choose a plan that proves inappropriate for the situation at hand. Although perceptual errors are generally less frequent in accident reports, they are as important as skill-based errors and decision errors. This type of error arises when pilots’ perception of the world differs from reality, such as misjudging the distance/altitude/airspeed.