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1,4-Dioxane Chemistry, Uses, and Occurrence
Published in Thomas K.G. Mohr, William H. DiGuiseppi, Janet K. Anderson, James W. Hatton, Jeremy Bishop, Barrie Selcoe, William B. Kappleman, Environmental Investigation and Remediation, 2020
Before 2000, 1,4-dioxane was an ingredient or impurity in aircraft deicing fluids and antifreeze solutions. The Air Transport Association reportedly listed the following components of deicing fluid in 1994: ethylene glycol or propylene glycol, water, surfactants (wetting agents), corrosion inhibitors (including flame retardants), pH buffers, dyes, 1,4-dioxane, and complex polymers as thickening agents (USEPA, 2000). Glycol deicing formulations were previously used to treat airport runways. Because 1,4-dioxane was an impurity as residual solvent carried over from production of glycol, past uses of glycol deicing agents could leave trace levels of 1,4-dioxane in soil and groundwater near runways. For removing hoarfrost and ice from an aircraft, a mixture of glycols, urea, and hot water is used, which is sprayed at high pressure onto the fuselage. Three of the four types of deicing formulations include 90%, 65%, and 65% glycol, and may contain additives (2%). Quantities of spray range from as low as 40 liters/plane (10 gallons) to as high as 15,000 liters/plane (3,960 gallons) for large aircraft during bad weather. Runoff concentrations have been measured as high as 160,000 mg/L propylene glycol at an airport in Connecticut, and 20,000 mg/L of ethylene glycol and diethylene glycol (DEG) at Dallas Fort Worth Airport and Kansas City International Airport (Sulej et al., 2012).
Applications
Published in Mike Tooley, PC Based Instrumentation and Control, 2013
A college department is engaged in research into the effectiveness of various methods of aircraft deicing based on the application of anti-icing fluids. The department has a wind tunnel capable of speeds of up to 80 m/s (Mach 0.28) supplied by a fan driven by a 10 HP variable speed DC motor. The test section can be adjusted through a pitch angle of ±20◦ and instrumentation can be attached to parts and components mounted in this section. The moving air stream is cooled by means of a refrigerated cooling unit such that airflow temperatures of between −18◦C and ambient can be produced.
The Business Value of Enterprise Energy Management at DFW Airport
Published in Barney L. Capehart, Timothy Middelkoop, Paul J. Allen, David C. Green, Handbook of Web Based Energy Information and Control Systems, 2020
Numerous PLCs were utilized for process automation throughout the DE plant and other utility processes on the airport including water distribution, wastewater collection, and collection, storage and treatment of spent aircraft deicing fluid. These systems were easily integrated with the Delta V using open bus standards (Modbus or Data Highway).
Dynamic behaviours and drying processes of water droplets impacting on superhydrophilic surfaces
Published in Surface Engineering, 2021
Yan Zhu, Jialiu Liu, Yongmao Hu, De-Quan Yang, Edward Sacher
Superhydrophilicity refers to the outstanding ‘water-loving’ behaviour of specifically designed surfaces. Such surfaces have been described, in many articles, as having static water contact angles of less than 5–10°, [1–5] a range considered to represent the complete spread of water on a surface [2–10]. There is no clear definition or consensus of superhydrophilicity [3,6,10], and the exact determination of a water contact angle near zero degrees is challenging [10]. Such surfaces have attracted attention, due to their many applications, including anti-fogging [11], bio-fouling prevention [12], biomedicine [13–17] and self-cleaning [18–21] capabilities. Additional applications, in practical environments that involve dynamic water impact on such surfaces, have persuaded us to give attention to the dynamic behaviours of water droplets on these surfaces, which, although not necessarily suited to heat transport [22–24], may be important in applications such as spraying, ink-jet printing [25], pharmaceuticals [26], aircraft deicing [27,28], microfluidic devices, droplet manipulation, cell screening and water harvesting through superhydrophilic–superhydrophobic patterned surfaces [29] or switching [30].
Microwave-heated high-silica glass cloth reinforced polyimide-based metamaterial absorber for aircraft deicing
Published in Journal of Microwave Power and Electromagnetic Energy, 2021
Zehai Zhang, Jun Zhang, Xiao Liu, Kun Zheng, Hongyi Yi, Jianshu Wang
In this study, the microwave heating ability of high-silica GCRP MA plates was investigated. Two rounds of microwave heating experiments were conducted. In the first, samples with reflectivity measuring between −6 and −4 dB were observed to have a heating capacity of approximately 0.001 °C/s/W, while in the second, a heating capacity of 0.01 °C/s/W was recorded for the new MA sample with a reflectivity of −7.63 dB. Thermal images captured following testing showed clear indications of microwave heating, as local uniform temperature distributions were observed within the unit cells of the MA. The combined results of both rounds of experiments suggest the possibility of application of MAs in aircraft deicing. In later research, we will further investigate the inconsistency between the measured reflectivity and the simulated reflectivity, and the mechanism dictating microwave heating in the MAs, and improve the absorption rate of the MA.
Evaluation of Fatigue and Workload among Workers Conducting Complex Manual Assembly in Manufacturing
Published in IISE Transactions on Occupational Ergonomics and Human Factors, 2021
Yaniel Torres, Sylvie Nadeau, Kurt Landau
We preferred the SPFS because of its simplicity. As a one-dimension scale, SPFS can be used repeatedly in the field with ease and in conjunction with other subjective evaluation methods. Also, the focus of the research was on complex manual assembly where physical demands are low to moderate. The SPFS has been used frequently in studies of self-reported levels of fatigue among commercial and military pilots (Honn et al., 2016; Neville et al., 1994), railroad workers (Dorrian et al., 2011), aircraft deicing technicians (Torres et al., 2016), and manufacturing workers (Binoosh et al., 2017). The scale has demonstrated good reliability in test–retest scenarios and has been found sensitive to variations in fatigue throughout the workday (Miller & Narvaez, 1986). The scale’s designers further defined four fatigue classes and their predicted effects on performance, with Class I and Class II being associated with significant performance degradation (Table 2). For this reason, the value 5, which constitutes the lower bound of Class II, is considered a critical threshold in civilian aviation (UK-CAA, 2007). In the present study, levels of fatigue sufficiently high to compromise performance (fatigue score ≥ 5: moderate/severe fatigue) were considered as “high fatigue”. Thus, the value 5 on the SPFS was used as the critical threshold serving to dichotomize the fatigue scale for statistical analysis.