Alternative Aircraft Fuels

The efficient utilization of fossil fuels by future jet aircraft may necessitate the broadening of current aviation turbine fuel specifications. The most significant changes in specifications would be an increased aromatics content and a higher final boiling point in order to minimize refinery energy consumption and costs. These changes would increase the freezing point and might lower the thermal stability of the fuel, and could cause increased pollutant emissions, increased combustor liner temperatures, and poorer ignition characteristics. This paper discusses the effects that broadened specification fuels may have on present-day jet aircraft and engine components and the technology required to use fuels with broadened specifications.

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Experimental Investigation of Thermal Characteristics of Kiwira Coal Waste with Rice Husk Blends for Gasification

Journal of Energy ◽

10.1155/2014/562382 ◽

2014 ◽

Vol 2014 ◽

pp. 1-8 ◽

Cited By ~ 1

Author(s):

Deodatus Kazawadi ◽

Geoffrey R. John ◽

Cecil K. King’ondu

Keyword(s):

Activation Energy ◽

Thermal Stability ◽

Rice Husk ◽

Energy Recovery ◽

Fossil Fuels ◽

High Energy ◽

Coal Waste ◽

Rice Husks ◽

Weight Percentage ◽

Thermal Stability Of

Eminent depletion of fossil fuels and environmental pollution are the key forces driving the implementation cofiring of fossil fuels and biomass. Cogasification as a technology is known to have advantages of low cost, high energy recovery, and environmental friendliness. The performance/efficiency of this energy recovery process substantially depends on thermal properties of the fuel. This paper presents experimental study of thermal behavior of Kiwira coal waste/rice husks blends. Compositions of 0, 20, 40, 60, 80, and 100% weight percentage rice husk were studied using thermogravimetric analyzer at the heating rate of 10 K/min to 1273 K. Specifically, degradation rate, conversion rate, and kinetic parameters have been studied. Thermal stability of coal waste was found to be higher than that of rice husks. In addition, thermal stability of coal waste/rice husk blend was found to decrease with an increase of rice husks. In contrast, both the degradation and devolatilization rates increased with the amount of rice husk. On the other hand, the activation energy dramatically reduced from 131 kJ/mol at 0% rice husks to 75 kJ/mol at 100% rice husks. The reduction of activation energy is advantageous as it can be used to design efficient performance and cost effective cogasification process.

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The Quantification and Improvement of the Thermal Stability of Aviation Turbine Fuel

Journal of Engineering for Gas Turbines and Power ◽

10.1115/1.3239915 ◽

1986 ◽

Vol 108 (2) ◽

pp. 381-386 ◽

Cited By ~ 4

Author(s):

J. S. Mills ◽

D. R. Kendall

Keyword(s):

Thermal Stability ◽

Operating Conditions ◽

Engine Oil ◽

Oxidation Reactions ◽

Fuel Performance ◽

Initiation Rate ◽

Radical Oxidation ◽

Aviation Turbine Fuel ◽

Thermal Stability Of

Studies of the propensity of aviation turbine fuels to lacquer engine oil-coolers that were described in an earlier paper have been extended to cover a wider range of fuels. Fuel performance was found to vary widely; some fuels were liable to lacquer oil-coolers to the extent of producing significant losses in efficiency at the most severe operating conditions currently encountered. Oxidation studies conducted in parallel with the rig investigations indicate that a fuel’s performance is strongly dependent on its tendency to initiate radical oxidation reactions. The relatively high initiation rate of less stable fuels is believed to be due in part to their trace content of metals that catalyze oxidation reactions. Accordingly, an approved metal deactivating additive has been examined as a means of improving the performance of such fuels.

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Effect of the Addition of Biobased Polyols on the Thermal Stability and Flame Retardancy of Polyurethane and Poly(Urea)Urethane Elastomers

Materials ◽

10.3390/ma14071805 ◽

2021 ◽

Vol 14 (7) ◽

pp. 1805

Author(s):

Kamila Mizera ◽

Kamila Sałasińska ◽

Joanna Ryszkowska ◽

Maria Kurańska ◽

Rafał Kozera

Keyword(s):

Thermal Stability ◽

Flame Retardancy ◽

Fossil Fuels ◽

Structural Characteristics ◽

Cone Calorimetry ◽

Current Trends ◽

Ft Ir ◽

The Impact ◽

Thermal Stability Of ◽

Ft Ir Spectroscopy

Due to the current trends in sustainable development and the reduction in the use of fossil fuels (Green Deal strategy and the circular economy), and thus, the increased interest of the polyurethane industry in polyols derived from renewable sources, it is important to study the impact of these polyols on the flammability of new bioelastomers. The goal of this study was to check the influence of biobased polyols, such as tall oil (TO)-based polyols, soybean oil (SO)-based polyol, and rapeseed oil (RO)-based polyol, on the reduction in the burning and fume emissions of polyurethane and poly(urea)urethane elastomers (EPURs and EPUURs). The thermal stability of these materials was tested using thermogravimetric analysis (TGA). In turn, the flame retardancy and smoke emissions were checked using a cone calorimetry test. The released gases were identified using TGA coupled with Fourier transform infrared (FT-IR) spectroscopy (TGA/FT-IR). Moreover, the morphological and structural characteristics of the char residues were characterized using FT-IR and scanning electron microscopy (SEM) with energy-dispersive spectroscopy (EDS). The obtained data were compared to the results received for elastomers produced with petroleum substrates. The addition of biobased polyols led to a reduction in the burning as a result of the formation of char, especially RO polyol. Moreover, the TO and RO polyols increased the thermal stability of the elastomers.

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The Ordered Phase Formation in Ti-Al-Ga Alloys

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100069193 ◽

1970 ◽

Vol 28 ◽

pp. 440-441

Author(s):

Shiro Fujishiro ◽

Harold L. Gegel

Keyword(s):

Thermal Stability ◽

High Temperature ◽

Titanium Alloys ◽

Growth Kinetics ◽

Stoichiometric Composition ◽

Good Potential ◽

Alpha Titanium ◽

Cold Rolled ◽

Kinetics Of ◽

Thermal Stability Of

Ordered-alpha titanium alloys having a DO19 type structure have good potential for high temperature (600°C) applications, due to the thermal stability of the ordered phase and the inherent resistance to recrystallization of these alloys. Five different Ti-Al-Ga alloys consisting of equal atomic percents of aluminum and gallium solute additions up to the stoichiometric composition, Ti3(Al, Ga), were used to study the growth kinetics of the ordered phase and the nature of its interface.The alloys were homogenized in the beta region in a vacuum of about 5×10-7 torr, furnace cooled; reheated in air to 50°C below the alpha transus for hot working. The alloys were subsequently acid cleaned, annealed in vacuo, and cold rolled to about. 050 inch prior to additional homogenization

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Microstructure studies of tungsten silicide schottky contacts on Gaas

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100126445 ◽

1987 ◽

Vol 45 ◽

pp. 328-329

Author(s):

Yih-Cheng Shih ◽

E. L. Wilkie

Keyword(s):

Thermal Stability ◽

Field Effect Transistors ◽

Schottky Contact ◽

Schottky Contacts ◽

Excellent Thermal Stability ◽

Barrier Heights ◽

Gaas Substrates ◽

Film Adhesion ◽

Threshold Voltages ◽

Thermal Stability Of

Tungsten silicides (WSix) have been successfully used as the gate materials in self-aligned GaAs metal-semiconductor-field- effect transistors (MESFET). Thermal stability of the WSix/GaAs Schottky contact is of major concern since the n+ implanted source/drain regions must be annealed at high temperatures (∼ 800°C). WSi0.6 was considered the best composition to achieve good device performance due to its low stress and excellent thermal stability of the WSix/GaAs interface. The film adhesion and the uniformity in barrier heights and ideality factors of the WSi0.6 films have been improved by depositing a thin layer of pure W as the first layer on GaAs prior to WSi0.6 deposition. Recently WSi0.1 has been used successfully as the gate material in 1x10 μm GaAs FET's on the GaAs substrates which were sputter-cleaned prior to deposition. These GaAs FET's exhibited uniform threshold voltages across a 51 mm wafer with good film adhesion after annealing at 800°C for 10 min.

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