General aviation aircraft driven by aviation piston engines (APE) have gained a broad range of applications. Aviation fuels blended with long-chain alcohols is a promising means for APE to mitigate ...its dependency on fossil fuel. Herein, the combustion and emission characteristics of an aviation compression ignition engine burning a baseline diesel, the RP-3 kerosene, and a synthetic Fischer-Tropsch (FT) fuel were analyzed. The engine tests were carried out under different conditions via varying pentanol additive ratio (PAR), fuel injection timing and engine load variables. The Response Surface Method (RSM) was utilized to quantify the effectiveness of independent variables on the target responses of indicated thermal efficiency (ITE), nitrogen oxides (NOx) and particulate matter (PM) emissions. Compared to the baseline diesel, burning the pentanol-FT blends (40% PAR) significantly reduces NOx by 81% and PM by 75% with a prominent increase of ITE by 7.2%. Based on the analysis of variance, the RSM-derived model demonstrated that the fuel type predominantly determines ITE and NOx, while PAR primarily alters PM emissions. The binary effects of independent variables on the target responses were further resolved quantitatively. Moreover, the RSM was well validated to implement effective prediction on the engine performance/emission characteristics.
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•Combustion/emission characteristics of an aviation piston engine was analyzed.•Pentanol addition elevated combustion efficiency and reduced emissions.•RSM models unraveled important variables on ITE and NOx and PM emissions.
The increasing interest in environmentally sustainable aviation has led to the topic becoming popular in aviation management literature. However, to the best of our knowledge, no research analyzes ...aviation environmental management (AEM) literature in a comprehensive manner. This study aims to bridge this gap by conducting a retrospective examination of environmental sustainability studies in literature using the bibliometric analysis method. Identifying potentially important gaps and drawing a comprehensive picture of the dynamics and the state of the literature is an important task to drive future studies in the field. Results drawn from 511 publications indexed in the Web of Science (WoS) database indicate a recent and rapid growth in the literature. Greenhouse gas emissions and noise emissions are dominant research themes while waste and water management topics are not well established. Studies investigating alternative fuels, emission mitigation strategies, energy conservation, and noise abatement are prevalent in the literature.
Reducing aviation emissions is important as they contribute to air pollution and climate change. Several alternative aviation fuels that may reduce life cycle emissions have been proposed. ...Comparative life cycle assessments (LCAs) of fuels are useful for inspecting individual fuels, but systemwide analysis remains difficult. Thus, systematic properties like fleet composition, performance, or emissions and changes to them under alternative fuels can only be partially addressed in LCAs. By integrating the geospatial fuel and emission model, AviTeam, with LCA, we can assess the mitigation potential of a fleetwide use of alternative aviation fuels on 210 000 shorter haul flights. In an optimistic case, liquid hydrogen (LH2) and power-to-liquid fuels, when produced with renewable electricity, may reduce emissions by about 950 GgCO2eq when assessed with the GWP100 metric and including non-CO2 impacts for all flights considered. Mitigation potentials range from 44% on shorter flights to 56% on longer flights. Alternative aviation fuels’ mitigation potential is limited because of short-lived climate forcings and additional fuel demand to accommodate LH2 fuel. Our results highlight the importance of integrating system models into LCAs and are of value to researchers and decision-makers engaged in climate change mitigation in the aviation and transport sectors.
To reduce carbon emissions, the European Union has implemented the Emissions Trading Scheme (ETS) since 2012 for intra-European commercial flights. In response, airlines have explored various means, ...including sustainable jet fuels. This article investigates how similar ETS policy would affect domestic carbon emissions when implemented in the United States. The study integrates a model of airlines operations optimization and multi-feedstock biojet fuels life cycle assessment to simulate decisions of biojet fuel and commercial aviation industry responding to an emission policy. We conduct a Monte-Carlo simulation on two scenarios of domestic emission schemes to investigate the adoption of biojet fuels and its impacts on carbon emissions. Our model indicates that implementing an emission policy for U.S. airlines could incentivize adoption of biofuels - a median value of 10% of total fuels in 2050- while only marginally reduce travel demand. Because of a combined effect of emission policy and improved aircraft technology, the emissions in 2050 would only increase 1.37 times the 2005 level despite passenger demand grows by a factor of 2.75. A non-parametric sensitivity analysis suggests that the price of oil, economic growth, and carbon price are the three most significant factors in affecting the fleet-level carbon emissions.
•Emissions trading scheme for U.S. airlines results in the adoption of biojet fuels.•In 2050 passenger demand will grow 2.75 (median value) times the 2005 level.•The emissions in 2050 will increase 1.37 (median value) times the 2005 level.•Oil price, economic growth, and carbon price are the three most significant factors.
Early Online Jacobson, B F; Louw, S; Schapkaitz, E ...
South African medical journal,
07/2024, Volume:
114, Issue:
7
Journal Article
Peer reviewed
Open access
Long-haul flights have been associated with a two- to four-fold increased risk of aviation-related thrombosis (ART). Several studies have investigated the extent to which hypoxic hypobaric exposure, ...dehydration and prolonged immobilisation during air travel induce changes in haemostasis.BACKGROUNDLong-haul flights have been associated with a two- to four-fold increased risk of aviation-related thrombosis (ART). Several studies have investigated the extent to which hypoxic hypobaric exposure, dehydration and prolonged immobilisation during air travel induce changes in haemostasis.To investigate the role of high altitude as a risk factor for ART.OBJECTIVETo investigate the role of high altitude as a risk factor for ART.Healthy volunteers aged ≥18 years (N=40), without risk factors for venous thromboembolism, were exposed to an exacerbated altitude of 18 000 feet (5 486 m) for 1 hour. During the flight, the oxygen (O2) levels of the participants, who received supplemental O2, were measured by pulse oximetry and maintained at >92%. Venous blood and urine samples were collected prior to departure and immediately after flying in an unpressurised twin-engine airplane. D-dimer levels, thromboelastography (TEG) parameters, von Willebrand factor (VWF) activity and urine osmolality were measured.METHODSHealthy volunteers aged ≥18 years (N=40), without risk factors for venous thromboembolism, were exposed to an exacerbated altitude of 18 000 feet (5 486 m) for 1 hour. During the flight, the oxygen (O2) levels of the participants, who received supplemental O2, were measured by pulse oximetry and maintained at >92%. Venous blood and urine samples were collected prior to departure and immediately after flying in an unpressurised twin-engine airplane. D-dimer levels, thromboelastography (TEG) parameters, von Willebrand factor (VWF) activity and urine osmolality were measured.The participants were 19 men and 21 women, with a mean (standard deviation) age of 46 (14) years. A significant difference in D-dimer levels, VWF activity, urine osmolality and TEG parameters (reaction (R) time, kinetic (K) time and maximum amplitude (MA)) before and after the 1-hour flight was observed (p<0.001). Urine osmolality correlated positively with VWF activity levels (r=0.469; p<0.002).RESULTSThe participants were 19 men and 21 women, with a mean (standard deviation) age of 46 (14) years. A significant difference in D-dimer levels, VWF activity, urine osmolality and TEG parameters (reaction (R) time, kinetic (K) time and maximum amplitude (MA)) before and after the 1-hour flight was observed (p<0.001). Urine osmolality correlated positively with VWF activity levels (r=0.469; p<0.002).Air travel at high altitude induced a hypercoagulable state in healthy volunteers. Future research should focus on whether thromboprophylaxis can significantly obviate the activation of coagulation in response to high altitude.CONCLUSIONAir travel at high altitude induced a hypercoagulable state in healthy volunteers. Future research should focus on whether thromboprophylaxis can significantly obviate the activation of coagulation in response to high altitude.
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•Blendstocks from aromatic amines, aromatic hydrocarbons, and MTBE with different percentages were blended.•Characteristics of produced fuel 100UL were as close as possible to the ...properties of commercial Avgas 100VLL.•Concentrations of m-toluidine and MTBE were within the range that has been tested on an industrial scale.
Even though tetraethyl lead (TEL) is the most effective of the known antiknock additives, especially in aviation gasoline, there has been a clear tendency to abandon its use. This present work investigates the creation of a novel promising technique for producing an unleaded aviation gasoline 100UL through studying the influence of various aromatic amines, aromatic hydrocarbons, and MTBE on the antiknock characteristics of model blends of isooctane and n-heptane. Additionally, a nonlinear change in the antiknock performance of aromatic amines was established as the detonation resistance of the base fuel increased with the essential role of the structure of the aromatic amine. The results indicated that the optimal composition of the produced fuel was contained 57 wt% of isooctane, 10 wt% of isopentane, 10 wt% of toluene, 5 wt% of isopropylbenzene 15 wt% of MTBE, 2 wt% of m-toluidine, and 1 wt% of isopropyl alcohol. What’s more, its characteristics were as close as possible to the properties of commercial aviation gasoline 100VLL and it did not contain other metal-containing additives. Finally, the concentrations of non-hydrocarbon additives, such as m-toluidine and MTBE were within the range that has been tested on an industrial scale during the operation of an automotive equipment in many countries of the world.
At the Dawn of Airpower: The U.S. Army, Navy, and Marine Corps' Approach to the Airplane, 1907-1917 examines the development of aviation in the U.S. Army, Navy, and Marine Corps from their first ...official steps into aviation up to the United States' declaration of war against Germany in April, 1917.
Timely and efficient air traffic flow management (ATFM) is a key issue in future dense air traffic. The emerging demands for unmanned aerial vehicles and general aviation aircraft aggravate the ...burden of the ATFM. Thanks to the advanced automatic dependent surveillance-broadcast (ADS-B) technique, the aerial vehicles can be tracked and monitored in a real-time and accurate manner, providing possibility for establishing a more intelligent ATFM architecture. In this article, we first form an aviation Big Data platform by using the distributed ADS-B ground stations and the obtained ADS-B messages. By exploring the constructed dataset and mapping the extracted information to the routes, the air traffic flow between different cities can be counted and predicted, where the prediction task is implemented on the basis of two machine learning methods, respectively. The experimental results based on real-world data demonstrate that the proposed traffic flow prediction model adopting long short-term memory (LSTM) can achieve better performance, especially when abnormal factors in traffic control are considered.
Ultrafine particles (UFP) contribute to adverse health outcomes such as asthma, obstructive pulmonary disease, cardiovascular disease, and lung cancer. Recent research draws attention to elevated ...ambient UFP number concentrations near airports. In this study, high time-resolution UFP measurements were conducted along public roads near Mohammad Ali International Airport (SDF; Louisville, KY) which is a commercial passenger airport and a major air cargo hub. Short-duration (∼3 h) measurements with two instrumented vehicles were designed and executed to capitalize on the distinct features of the air cargo hub including periods of high flight activity (and either all landings or all take-offs) at night and early morning when the atmospheric mixing layer depth is shallow. We present preliminary measurements for quantifying individual aircraft contributions and showcase the complexities involved in interpreting these data. For example, during periods with high arrivals frequency, UFP plumes from multiple aircraft on approach are superposed and it is challenging to apportion impacts to individual aircraft. Ground-level impacts for individual aircraft on climb-out are difficult to discern because the planes rapidly ascend above the atmospheric mixed layer height and take different flight paths soon after take-off. Elevated UFP concentrations are observed downwind of the airport, in some cases admixed with approach/climb-out emissions. Although from these data UFP concentrations are difficult to associate with specific aircraft characteristics, UFP concentrations are elevated downwind of the airport. These impacts decrease with increasing distance from the airport yet are clearly discernible at least 3 km downwind.
Abstract
Introduction
Sleep loss and circadian disruption pose a significant risk in safety-sensitive occupations. In aviation, many studies have demonstrated how inflight rest locations influence ...alertness and performance among pilots, but few studies have evaluated cabin crew. The purpose of the present study was to evaluate sleep outcomes among cabin crewmembers sleeping in a bunk compared to a jump seat during one long-haul route.
Methods
Thirty-one (6 male) cabin crewmembers (age M = 30, SD = +/-13) flew the same long-haul route (outbound and return) with a flight duration of 10:41 (± 0:14) hours. Participants were randomly assigned to fly on an aircraft with a bunk or a jump seat for their sleep opportunity. Participants wore an Actiwatch (Phillips-Respironics Spectrum) throughout the entire study and completed a sleep diary at bedtime and upon waking. During flight they completed a nap diary entering the start time of the inflight sleep (if any) and the duration.
Results
Sixty-five flights (32 outbound and 33 return) were included in the analyses. Seventy-seven percent of the flights had a bunk and 23% had a jump seat. Crewmembers obtained M = 146.46 (± 67.20) minutes of rest out of which they slept M = 125.33 (± 64.91) minutes in the bunk. While using the jump seat, crewmembers obtained M = 169.53 (± 133.30) minutes of rest out of which they slept M = 142.92 (± 149.72) minutes. When crewmembers slept in the bunk, sleep latency was shorter (M = 13.69 ± 12.64 minutes) and efficiency was better (M = 76.16 ± 16.09 %) compared to the jump seat (sleep onset: M = 16.77 ± 13.89 minutes; sleep efficiency: M = 60.64 ± 17.42 %).
Conclusion
We found that cabin crewmembers slept for longer time when they used the jump seat. They fell asleep faster and their sleep efficiency was better when using the bunk compared to the jump seat. Further research is needed to understand how sleep quality and subsequent performance are influenced by sleep opportunity in a bunk compared to a jump seat.
Support (if any)
NASA Airspace Operations and Safety Program, System-Wide Safety Project.
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