Aircraft Deicing Research Articles

A novel low pH fermentation process for the production of acetate and propylene glycol from carbohydrate wastes

A novel low pH fermentation process was studied for the conversion of lactose using Lactobacillus plantarum and Lactobacillus buchneri under anoxic conditions in single co-culture, and two-stage sequential fermentations. This is aimed at producing acetate and propylene glycol (PG) as environmentally benign substitutes for currently used road and aircraft deicing chemicals. The results indicate that in the case of two-stage fermentation with immobilized L. buchneri in the second stage, lactose degradation rate increased markedly producing acetate and PG concentrations of 12.1 and 10.7 g L−1 at pH 3.8. In the case of coculture fermentation, the acetate and PG concentrations were 8.2 and 6.8 g L−1, respectively. Fermentation of lactose and whey powder was conducted at pH 4.25 using a high cell density culture of L. buchneri. The acetate and PG yields were similar for both substrates at ∼0.3 g/g and ∼0.33 g/g respectively. With a starting lactose concentration of 60 g/L, acetate and PG concentrations of 18 g/L and 21 g/L respectively were obtained. The low pH conversion of wastes to value-added products under anoxic conditions provides substantial operating benefits over neutral pH fermentations that require strict anaerobic conditions for effective operation. Moreover, the low product pH at around 4.0 will provide substantial savings in downstream processing costs due to the much higher extraction efficiency of weak- and moderate- base resins for acetic acid compared to acetate ion.

Study of Shape Memory Alloy De-icing Device for Nonrotating Components of Aircrafts

Shape memory alloy (SMA) is a promising material which has widely been applied in aerospace industry. Its unique nature of the high stress output rate and low power requirement agrees the need of energy saving in aircraft de-icing. Among the few designs of the SMA de-icer, Gerardi’s project for rotating blade is more fit to the requirement of the de-icer for aircrafts. However, it is not clear that if the de-icer is capable to de-icing for non-rotating components or not. In this study, design of the SMA de-icer for non-rotating components were presented. Characteristics of the SMA de-icer and factors influence on it were confirmed by numerical methods. The major results show that the SMA de-icer can achieve de-icing objective well. De-icing rate of 100% can be obtained. For the designed SMA de-icer, pre-strain of 4% of the SMA sheet is recommended. Thinner SMA sheet helps greatly improve de-icing performance of the SMA de-icer.

Enhanced CO2 Electrochemical Conversion at Bi-Modified Pb Foams

CO2 conversion methods to remediate anthropogenic emissions appear promising, as they offer the potential to produce liquid and gaseous fuels for use either in the aeronautics industry, or as a chemical storage method for intermittent energy produced by windmills and photovoltaic panels. Fuel synthesis may be achieved via either the production of a syngas mixture (H2 and CO) through the water gas shift reaction and subsequent conversion into hydrocarbon fuel, or by direct electrochemical reduction of CO2. Direct electrochemical conversion of CO2 into value-added products is a low-temperature process, with the advantage of requiring relatively simple equipment. Formic acid, or formate salts, are used in a variety of chemical processes such as electrowinning, leather tanning, and aircraft de-icing. Alternatively, formic acid and formate salts may be considered as a hydrogen storage medium. On top of that, direct formic acid, and more recently direct formate, fuel cells, have been investigated as they demonstrate significant benefits over methanol fuel cells, including higher open circuit voltage and lower crossover. Pb and Bi are promising catalysts with good selectivity for formate. In the case of lead, it can be prepared in the form of dendrites with nanometre-sized tips. Local high electric fields can exist at the tip of these dendrites that can induce a concentration of electrolytes which in turn leads to improve electroreduction of CO2 [[1]]. Bismuth is non-toxic and has negligible environmental impact. It has few commercial applications, and its price has been low and relatively stable in recent years. In this work, we studied the activity and stability for CO2 electroreduction onto high surface area metallic Pb films. The latter Pb films were further functionalized by Bi overlayers to enhance CO2 reduction properties. For both materials, the material films were prepared through a potentiostatic method. Both types of films were extensively characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HR-TEM) and x-ray diffraction (XRD), while electrochemical activities were characterized by cyclic voltammetry (CV), linear sweep voltammetry (LSV), and potentiostatic measurements. [1] M. Fang, S. Garbarino, G.A. Botton, A.C. Tavares and D. Guay, J. Mater. Chem A 5 (2017) 20747-20756

Parametric Studies of Flat Plate Trajectories Using VIC and Penalization

Flying debris is generated in several situations: when a roof is exposed to a storm, when ice accretes on rotating wind turbines, or during inflight aircraft deicing. Four dimensionless parameters play a role in the motion of flying debris. The goal of the present paper is to investigate the relative importance of four dimensionless parameters: the Reynolds number, the Froude number, the Tachikawa number, and the mass moment of inertia parameters. Flying debris trajectories are computed with a fluid-solid interaction model formulated for an incompressible 2D laminar flow. The rigid moving solid effects are modelled in the Navier-Stokes equations using penalization. A VIC scheme is used to solve the flow equations. The aerodynamic forces and moments are used to compute the acceleration and the velocity of the solid. A database of 64 trajectories is built using a two-level full factorial design for the four factors. The dispersion of the plate position at a given horizontal position decreases with the Froude number. Moreover, the Tachikawa number has a significant effect on the median plate position.

Data-driven optimization for Dallas Fort Worth International Airport deicing activities

Airplane deicing is a safety measure to eliminate/prevent icing on airplanes that can lead to airflow disruption and emergency conditions. Aircraft deicing/anti-icing fluids (ADF) are high in glycol content. At Dallas Fort Worth International Airport (DFW), the major aircraft deicing activities are conducted at designated deicing pads called Source Isolation Deicing Sites, where ADF run-off can be captured and conveyed into the airport’s glycol collection system. A portion of ADF drips from the aircraft during taxiing and shears off the aircraft during take-off, entering nearby waterways without treatment. Glycol acts as a nutrient for bacteria in the airport’s receiving waterways, resulting in an increase in bacterial growth and a subsequent reduction in dissolved oxygen (DO), potentially endangering aquatic life. This paper proposes a prototype data-driven deicing activities management framework for DFW to address the complexity of airport deicing operations and its impacts. The proposed framework uses stochastic dynamic programming (SDP) to assign airplanes in each hour to deicing pad locations, so as to maximize DO in the receiving waters, subject to airport constraints. Some data were artificially generated using the available knowledge of airport operations. The state transition equations in SDP were estimated. The proposed framework was demonstrated using three cases during major deicing events. Improvements in DO compared with actual DO recorded in the data were mixed; however, the results motivated DFW to implement a new data collection process to replace the artificially-generated data, so that a more accurate optimization could be conducted in the future.

(Keynote) Formate/Formic Acid Synthesis from CO2 Electroduction Using Bi and Pb Nanostructures

The rise in atmospheric CO2 concentration since the beginning of the Industrial Age has raised concerns on its potential effect on global temperatures. While several factors such as natural climate changes, variations in solar activity, and volcanic eruptions may also contribute to observed variations in CO2 concentrations, it has been well established that anthropogenic emissions contribute to the annual emission of over 30 billion tonnes of CO2, only about half of which is recycled through natural pathways. CO2 conversion into value-added products is an avenue explored to mitigate environmental issues. Conversion methods appear promising, as they offer the potential to produce liquid and gaseous fuels for use either in the aeronautics industry, or as a chemical storage method for the intermittent energy produced by windmills and photovoltaic panels. Fuel synthesis may be achieved via either the production of a syngas mixture (H2 and CO) through the water gas shift reaction and subsequent conversion into hydrocarbon fuel through processes such as Fisher-Tropsch, or by direct electrochemical reduction of CO2. While all methods may result in similar conversion yields, depending on the catalyst used, direct electrochemical conversion of CO2 into value-added products is a low-temperature process, with the further advantage of requiring relatively simple equipment. Formic acid, or formate salts, are used in a variety of chemical processes such as electrowinning, leather tanning, and aircraft de-icing. Alternatively, formic acid and formate salts may be considered a hydrogen storage medium. Direct formic acid, and more recently, direct formate fuel cells, have been investigated in the literature as they demonstrate significant benefits over methanol fuel cells, including higher open circuit voltage and lower crossover. Pb and Bi are promising catalysts with good selectivity for formate. Bismuth is non-toxic and has negligible environmental impact. It has few commercial applications, and its price has been low and relatively stable in recent years. In the case of Lead, it can be prepared in the form of dendrites with nanometre-sized tips. Local high electric fields can exist at the tip of these dendrites that can induce a concentration of electrolyte which in turn leads to a high local concentrations of CO2. In this study, we compared the activity and stability for CO2 electroreduction of high surface area metallic Bi and Pb films. In both cases, the materials films were prepared through a direct electrodeposition (potentiostatic method). Both types of films were extensively characterised by scanning electron microscopy (SEM), transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HR-TEM) and x-ray diffraction (XRD), while electrochemical activities were characterized by cyclic voltammetry (CV), linear sweep voltammetry (LSV), and potentiostatic measurements. Figure 1

De-Icing of aircraft: Incorporating business risks and occupational health and safety

De-Icing of aircraft: Incorporating business risks and occupational health and safety

Transcriptomic, cellular and life-history responses of Daphnia magna chronically exposed to benzotriazoles: Endocrine-disrupting potential and molting effects.

Benzotriazoles (BZTs) are ubiquitous aquatic contaminants used in a wide range of industrial and domestic applications from aircraft deicers to dishwasher tablets. Acute toxicity has been reported in aquatic organisms for some of the BZTs but their mode of action remains unknown. The objectives of this study were to evaluate the transcriptomic response of D. magna exposed to sublethal doses of 1H-benzotriazole (BTR), 5-methyl-1H-benzotriazole (5MeBTR) and 5-chloro-1H-benzotriazole (5ClBTR) using RNA-sequencing and quantitative real-time PCR. Cellular and life-history endpoints (survival, number of neonates, growth) were also investigated. Significant effects on the molting frequency were observed after 21-d exposure to 5MeBTR and 5ClBTR. No effects on molting frequency were observed for BTR but RNA-seq results indicated that this BZT induced the up-regulation of genes coding for cuticular proteins, which could have compensated the molting disruption. Molting in cladocerans is actively controlled by ecdysteroid hormones. Complementary short-term temporal analysis (4- and 8-d exposure) of the transcription of genes related to molting and hormone-mediated processes indicated that the three compounds had specific modes of action. BTR induced the transcription of genes involved in 20-hydroxyecdysone synthesis, which suggests pro-ecdysteroid properties. 5ClBTR exposure induced protein activity and transcriptional levels of chitinase enzymes, associated with an impact on ecdysteroid signaling pathways, which could explain the decrease in molt frequency. Finally, 5MeBTR seemed to increase molt frequency through epigenetic processes. Overall, results suggested that molting effects observed at the physiological level could be linked to endocrine regulation impacts of BZTs at the molecular level.

Ergonomic Time and Motion Studies of Aircraft De-icing Work

This paper reports results of time and motion studies and ergonomic consequences of aircraft de-icing work. De-icing of aircraft on the ground is extremely important for maximizing technical safety, but also a major challenge for persons performing it. Between December 2016 and March 2017 we carried out video-supported time and motion studies on 11 personnel performing de-icing work in open baskets at a Canadian airport. Total time analyzed was 788 min, during which 1192 individual observations were made. Our observation sessions varied in length from 59 to 96 min, partly for weather reasons. After ascertaining the work systems used by the de-icers and determining the principal factors influencing them, we used REFA methods to perform a hierarchical analysis of work activities. Energy turnovers generated by these activities were calculated. These lie between 4 and 13 kJ/min, depending on weather conditions, air traffic density and individual work patterns of the de-icing personnel. Contributions of the individual activities to total value added were classified. Roughly one third of the de-icing activities made a direct contribution. The remaining two thirds made only indirect contributions or none at all. Stresses arising from the work were compared with the few findings reported in the literature. Further investigations are needed to understand thoroughly centralized de-icing activities.

Experiment investigation on deicing characteristics and energy efficiency using infrared ray as heat source

The adhesion and accretion of ice on ground aircraft always pose potential problem to aircraft engine operation and safety performance. Currently, chemical deicing technology is often used for aircraft deicing. However, it is effective, but not environmental-friendly, cost-effectively and always compromises material performance of aircraft. Infrared ray (IR) deicing technology, by contrast, is proved to be a promising deicing technology due to its high efficiency, safety performance and environment protection. However, the energy efficiency of IR deicing technology and physical process of ice melt have not been fully researched and understood. It is therefore necessary to study them to improve the IR deicing performances. In this paper, some important characteristics of IR deicing were firstly investigated, including ice melt rate, variation of ice temperatures and mass. Secondly, the heat transfer mechanism through whole deicing process was studied. Finally, based on the experiment results, the energy efficiency of IR deicing was calculated and discussed. And the studied results showed that the maximum energy efficiency of IR deicing could reach 53.1% at the highest setting temperature 2273 K. For melting 6.5 kg ice, the melt time was 1746 s and 1002 s at setting temperature 1073 K and 2073 K, respectively.

Potential toxic effects of aircraft de-icers and wastewater samples containing these compounds

One of the major problems of airport operation is the impact of pollution caused by runoff waters. Runoff waters at an airport may contain high concentrations of different contaminants resulting from various activities of its operation. High quantities of aircraft de-icing/anti-icing fluids are used annually at airports worldwide. Aircraft de-icers and anti-icers may have negative environmental impacts, but their effects on aquatic organisms are virtually unknown. In order to address this issue, aircraft de-icers, pavement de-icers and wastewater samples were obtained from a regional airport. To evaluate the toxicity of wastewater samples and aircraft de-icing/anti-icing fluids (ADAFs), two bio-tests were performed: the Lemna growth inhibition test according to OECD guideline 221 and the luminescent bacteria test according to ISO guideline 11348-2. In the Lemna growth inhibition test, phytotoxicity was assessed using the endpoints frond number and frond area. The luminescent bacteria test involved the marine bacterium Vibrio fischeri. The estimates of effective concentrations (EC50) values were determined using the free software R and the "drc" library. Aquatic plants and marine bacteria showed a higher sensitivity towards ADAFs than to wastewater samples. Experiments showed that aircraft de-icing/anti-icing fluids and wastewater samples were relatively more toxic towards Lemna gibba L. in comparison to V. fischeri.

Mild and General Access to Diverse 1H-Benzotriazoles via Diboron-Mediated N-OH Deoxygenation and Palladium-Catalyzed C-C and C-N Bond Formation.

Benzotriazoles are a highly important class of compounds with broad-ranging applications in such diverse areas as medicinal chemistry, as auxiliaries in organic synthesis, in metallurgical applications, in aircraft deicing and brake fluids, and as antifog agents in photography. Although there are numerous approaches to N-substituted benzotriazoles, the essentially one general method to N-unsubstituted benzotriazoles is via diazotization of o-phenylenediamines, which can be limited by the availability of suitable precursors. Other methods to N-unsubstitued benzotriazoles are quite specialized. Although reduction of 1-hydroxy-1H-benzotriazoles is known the reactions are not particularly convenient or broadly applicable. This presents a limitation for easy access to and availability of diverse benzotriazoles. Herein, we demonstrate a new, broadly applicable method to diverse 1H-benzotriazoles via a mild diboron-reagent mediated deoxygenation of 1-hydroxy-1H-benzotriazoles. We have also evaluated sequential deoxygenation and Pd-mediated C-C and C-N bond formation as a one-pot process for further diversification of the benzotriazole moiety. However, results indicated that purification of the deoxygenation product prior to the Pd-mediated reaction is critical to the success of such reactions. The overall chemistry allows for facile access to a variety of new benzotriazoles. Along with the several examples presented, a discussion of the advantages of the approaches is described, as also a possible mechanism for the deoxygenation process.

Single Neuron PID Control of Aircraft Deicing Fluids Rapid Heating System

Aircraft deicing fluids rapid heating system is widely used in aircraft ground deicing to ensure that the operation of flights can be safe and efficient. Aiming at the temperature turbulence problem of aircraft deicing system, this paper presents the single neuron PID control strategy which combine the advantage of conventional PID control with artificial neuron control. The aircraft deicing fluids rapid heating system and the scheme and working principle of the system is introduced. Simulation is executed on the basis of the mathematical model of aircraft deicing fluids rapid heating system, which is built in this paper, according to a number of data collected by experiments which are operated on the experimental platform of deicing fluids rapid heating system. The simulation results show that the single neuron PID control strategy perform effectively on the temperature turbulence problem of aircraft deicing fluids rapid heating system. Experiments are conducted to vertify the single neuron PID control strategy, the results of which show that the single neuron PID control strategy can achieve the request in practical application of the aircraft deicing fluids rapid heating system.

Rheology of Poly(acrylic acid) in Water/Glycol/Salt Mixtures

Aqueous mixtures of 1,2-propylene glycol with added poly(acrylic acid), neutralized and with added salt, are used for aircraft deicing. This study reports data on the effects of varying the salt concentration, architecture, and temperature of a series of different mixtures. For a deicing fluid to be effective, it is desirable that it be able to create a liquid layer that is stable under low-shear conditions yet can be completely removed during the initial stages of takeoff. A number of the mixtures examined show a viscosity profile that is either almost independent of temperature or exhibits a peak. To gain a greater understanding of the factors responsible for the observed rheological behavior, a theoretical model was fitted to oscillatory data. Using two fitting parameters, it was possible to describe the changes in the observed behavior, suggesting that, as the temperature is varied, the extent of shielding of carboxylic acid groups and the conformation of the chain balance one another to give an apparent temperature independence of the viscosity. The rheological data were used to interpret the boundary-layer displacement thickness data obtained from wind-tunnel measurements.

Game Model Solution of Aircraft Deicing Operation Scheduling Based on Shapley Value

The aircraft deicing process is discussed to establish the airlines cooperative game model. The characteristic function and the core of the airlines coalition game model are analyzed, and then the solution of the model is proposed based on Shapley value. Finally, the result of the simulation shows that the cooperative game model motivates the cooperative action. The algorithm based on the Shapley value can meet both individual rationality and collectivity rationality. The results show the distribution is more reasonable and better.

Modeling and Simulation of the Aircraft Deicing Vehicle Based on Pro/E

The domestic QYZ5200TCB aircraft deicing vehicle is studied. Three dimensional solid modeling, virtual assembly, dynamic simulation, interference check and kinetic modeling are performed to the manipulator and Leveling Mechanism of the aircraft deicing vehicle under Pro/Engineer environment. The Virtual Prototype Development and Design is realized under the Pro/Engineer environment， which founds a basis for the further design optimization 、analysis and manufacture of products.

Analysis of the Pulsation in Aircraft Deicing System

Two methods are proposed in the paper to reduce the flow and pressure pulsation caused by the reciprocating pump in aircraft deicing system. First, the control algorithm for multiple phases of pumps is used to cut down the pulse energy among the pumps. Then the inflatable accumulator is used in combination with pumps to make the fluid more stable. At last, the simulation results show that the methods can effectively decrease the pulsation in the system.

Optimization Research of the Aircraft Deicing Problem

The theory of aircraft ground deicing processes is studied in this paper. Aiming at the civil aviation airport with a number of parking bays, a model considering multiple constraints is presented. According to the first come first service scheduling, simulation is carried out to get the relationship between the quantity of flights and the delay time, based on the flight plan data of Beijing Capital International Airport. Then, taking into account the cooperation of the airports with airlines, besides the competition between airline companies, priority comparison method is proposed to optimize the airline flight deicing scheme. The result of research shows that the optimization method can effectively reduce the delay time.

How Well Are We Measuring Snow: The NOAA/FAA/NCAR Winter Precipitation Test Bed

This paper presents recent efforts to understand the relative accuracies of different instrumentation and gauges with various windshield configurations to measure snowfall. Results from the National Center for Atmospheric Research (NCAR) Marshall Field Site will be highlighted. This site hosts a test bed to assess various solid precipitation measurement techniques and is a joint collaboration between the National Oceanic and Atmospheric Administration (NOAA), NCAR, the National Weather Service (NWS), and Federal Aviation Administration (FAA). The collaboration involves testing new gauges and other solid precipitation measurement techniques in comparison with World Meteorological Organization (WMO) reference snowfall measurements. This assessment is critical for any ongoing studies and applications, such as climate monitoring and aircraft deicing, that rely on accurate and consistent precipitation measurements.

Oxygen Demand of Aircraft and Airfield Pavement Deicers and Alternative Freezing Point Depressants

Aircraft and pavement deicing formulations and other potential freezing point depressants were tested for biochemical oxygen demand (BOD) and chemical oxygen demand (COD). Propylene glycol-based aircraft deicers exhibited greater BOD5 than ethylene glycol-based aircraft deicers, and ethylene glycol-based products had lower degradation rates than propylene glycol-based products. Sodium formate pavement deicers had lower COD than acetate-based pavement deicers. The BOD and COD results for acetate-based pavement deicers (PDMs) were consistently lower than those for aircraft deicers, but degradation rates were greater in the acetate-based PDM than in aircraft deicers. In a 40-day testing of aircraft and pavement deicers, BOD results at 20°C (standard) were consistently greater than the results from 5°C (low) tests. The degree of difference between standard and low temperature BOD results varied among tested products. Freshwater BOD test results were not substantially different from marine water tests at 20°C, but glycols degraded slower in marine water than in fresh water for low temperature tests. Acetate-based products had greater percentage degradation than glycols at both temperatures. An additive component of the sodium formate pavement deicer exhibited toxicity to the microorganisms, so BOD testing did not work properly for this formulation. BOD testing of alternative freezing point depressants worked well for some, there was little response for some, and for others there was a lag in response while microorganisms acclimated to the freezing point depressant as a food source. Where the traditional BOD5 test performed adequately, values ranged from 251 to 1,580 g/kg. Where the modified test performed adequately, values of BOD28 ranged from 242 to 1,540 g/kg.