Browse Topic: Oxygen

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The Portable Helicopter Oxygen Delivery System (PHODS) in the Altitude Chamber: Cerebral and Peripheral Blood Oxygen and Perceptual VigilanceF-0078-2022-175125/10/2022
ABSTRACT
Ard, Dennis, Petrassi, Frank, Temme, Leonard, Bowers,  Bobby, Hayes,  Amanda, St.Onge,  Paul, McAtee, Aaron
Insulating Component, Molded, Electrical, Heat Shrinkable, Connector and Cable Accessory, Sealing Strain Relief, General Specification ForAS5258A (Current)10/13/2021
This specification covers connector and cable accessory heat shrinkable, electrical insulating, molded components fabricated from various polymer based compositions. These components are intended for use as connector and cable accessory components to provide strain relief, electrical insulation, and environmental sealing.
AE-8C1 Connectors Committee
Minimum Standard for Portable Gaseous, Oxygen EquipmentAS1046C (Historical)8/11/2021
This standard is intended to apply to portable compressed gaseous oxygen equipment. When properly configured, this equipment is used either for the administration of supplemental oxygen, first aid oxygen or smoke protection to one or more occupants of either private or commercial transport aircraft. This standard is applicable to the following types of portable oxygen equipment: a Continuous flow 1 Pre-set 2 Adjustable 3 Automatic b Demand flow 1 Straight-demand 2 Diluter-demand 3 Pressure-demand c Combination continuous flow and demand flow.
A-10 Aircraft Oxygen Equipment Committee
Aluminum Alloy Powder 4.6Cu - 3.4Ti - 1.4B - 0.75Ag - 0.27MgAMS7033 (Current)6/22/2021
This specification covers an aluminum alloy in the form of pre-alloyed powder.
AMS AM Additive Manufacturing Metals
FITTING, PORT PLUG AND BLEEDERAS5169C (Historical)2/1/2021
G-3, Aerospace Couplings, Fittings, Hose, Tubing Assemblies
Terminology for Titanium MicrostructuresAS1814F (Current)7/16/2020
This list of terms, with accompanying photomicrographs where appropriate, is intended as a guide for use in the preparation of material specifications.
AMS G Titanium and Refractory Metals Committee
Lubricants for Oxygen UseAIR4071A (Current)7/14/2020
This SAE Aerospace Information Report (AIR) describes two classes of lubricants which, when properly applied, can be used in oxygen systems and components.
A-10 Aircraft Oxygen Equipment Committee
Steel, Bars and Forgings 2.0Cr - 10Ni - 8.0Co - 1.0Mo (0.10 - 0.14C) (HY-180) Double Vacuum Melted Solution Heat Treated, Marage HardenableAMS6543G (Current)6/29/2020
This specification covers a premium aircraft-quality maraging steel in the form of bars 0.50 inch (12.7 mm) and over in nominal diameter or least distance between parallel sides, forgings, and forging stock.
AMS E Carbon and Low Alloy Steels Committee
Aluminum Alloy Powder 10.0Si - 0.35MgAMS7018 (Current)5/11/2020
This specification covers an aluminum alloy in the form of pre-alloyed powder.
AMS AM Additive Manufacturing Metals
Color-Changing Bandages Sense and Treat Bacterial InfectionsTBMG-362533/1/2020
According to the World Health Organization, antibiotic resistance is one of the biggest threats to global health. Sensing and treating bacterial infections earlier could help improve patients’ recovery, as well curb the spread of antibiotic-resistant microbes. Now, researchers reporting in ACS Central Science have developed color-changing bandages that can sense drug-resistant and drug-sensitive bacteria in wounds and treat them accordingly.
Leading Women in Engineering & Science: Yolita Wildman Nugent, Director, Advanced Soft Systems Integration, FlexTBMG-362503/1/2020
Iron Nanorobots Destroy Cancer CellsTBMG-362383/1/2020
Drug-coated iron nanowires that can be guided to the site of a tumor using an external magnetic field before activating a three-step cancer-killing mechanism could provide an effective option for cancer therapy.
Liquid Flow Influenced by a Quantum Effect in WaterTBMG-360282/1/2020
Water is the basis of all life on earth. Its structure is simple — two hydrogen atoms bound to one oxygen atom — yet its behavior is unique among liquids, and scientists still do not fully understand the origins of its distinctive properties.
Evaluation of the Effects of Hydrogen Peroxide on Common Aircraft Electrical MaterialsTBMG-360582/1/2020
Among all of the large-scale disinfection and/or decontamination technologies available, vaporized hydrogen peroxide (VHP®) is of particular interest due to its rapid sterilization, easy usage, intrinsic environmental friendliness (i.e. simple by-products composed of only water and oxygen), and compatibility with many materials and systems.
Process Synthesizes Carbon Nanotubes Using Carbon DioxideTBMG-359612/1/2020
Carbon nanotubes are supermaterials that can be stronger than steel and more conductive than copper. The reason they're not in every application from batteries to tires is that these properties only show up in the tiniest nanotubes, which are extremely expensive. A new process was developed that can make these materials from carbon dioxide drawn from the air, in a way that is much less expensive than other methods. These materials could impact how emissions can be used in future technology.
Breathable Electronic Skin Using Nanofiber SubstrateTBMG-358071/1/2020
Wearable electronic devices for health monitoring using electronic skin have emerged but most electronic skin-related technologies utilize materials such as plastic or rubber that can cause skin irritation or interfere with metabolism when attached to skin or biological tissue.
Potassium-Oxygen Battery Stores Clean EnergyTBMG-3569212/1/2019
Researchers have developed a more efficient, more reliable potassium-oxygen battery with a cathode that stores the energy produced by a chemical reaction in a metal-oxygen or metal-air battery. The battery could make renewable energy sources like solar and wind more viable options for the power grid through cheaper, more efficient energy storage.
Superconductivity in a Nickel Oxide MaterialTBMG-3568912/1/2019
Scientists have made the first nickel oxide material that shows clear signs of superconductivity — the ability to transmit electrical current with no loss. Also known as a nickelate, it's the first unconventional superconductor that is very similar to copper oxides, or cuprates, which indicated that superconductors could someday operate at near-room-temperature and revolutionize electronic devices, power transmission, and other technologies. Those similarities may show that nickelates could also superconduct at relatively high temperatures.
Precipitation Hardenable Steel Alloy, Corrosion and Heat-Resistant Powder for Additive Manufacturing 16.0Cr - 4.0Ni - 4.0Cu - 0.30NbAMS7012 (Current)11/14/2019
This specification covers a corrosion and heat-resistant steel alloy in the form of pre-alloyed powder.
AMS AM Additive Manufacturing Metals
Thin Nylon Films for Transparent Electronic DevicesTBMG-3525510/1/2019
Very thin nylon films were created that can be used in electronic memory components. The films are several hundreds of times thinner than a human hair and could be used in bendable electronic devices or for electronics in clothing.
Invisible Tags Write, Read, and Erase Using LightTBMG-3526910/1/2019
A method was developed that enables information to be contained in simple plastic foils with a thickness of less than 50 μm, which is thinner than a human hair. Organic luminescent molecules are introduced into the transparent plastic foils. In the beginning, these molecules are in an inactive, dark state; by locally using ultraviolet irradiation, it is possible to turn this dark state into an active, luminescent one.
Wristbands Do Health Check During WorkoutTBMG-345646/1/2019
Next-generation fitness sensors could give deeper insights into human health through noninvasive testing of bodily fluids. A stretchy patch developed at KAUST could help this approach by making it easier to analyze sweat for critical biomarkers.
Graphene Coating Takes Oxygen Out of Lithium Battery FiresTBMG-346016/1/2019
Lithium batteries allow electric vehicles to travel several hundred miles on one charge. Their capacity for energy storage is well known — so is their tendency to occasionally catch on fire. This “thermal runaway” occurs most frequently when the batteries overheat or cycle rapidly.
Material Property Characterization for Low Pressure Carburization Process Design using Computer ModelingF-0075-2019-146805/13/2019
Low Pressure Carburization (LPC) is widely used in the aerospace industry for hardening components made of steels with high alloy content and high heat resistant properties. The traditional gas carburizing process often generates Intergranular Oxidation (IGO) near the surface due to the existence of oxygen in the furnace atmosphere, which needs to be removed by grinding after hardening to restore bending and contact fatigue performance. LPC processing is done in a low pressure chamber without the existence of oxygen, so the surface microstructure is improved by eliminating IGO. High temperature resistant steels require high alloy element contents, and some elements are strong carbide formers, such as Cr, Mn, Mo, and V, etc. During LPC processing, both iron and alloy carbides can be formed, which significantly affect the carburization time required to reach a specified case depth and surface carbon. The carbides formed during the LPC process may not decompose completely prior to quench hardening, and these primary carbides will end up in the final processed parts. If the size of these primary carbides is not controlled, both bending and contact fatigue performance may be decreased. In order to control carbide formation during LPC, the carbon diffusivity of a material must be characterized. This characterization was recently performed under a program between DANTE Solutions and the Combat Capabilities Development Command Aviation and Missile Center (CCDC AvMC). In this research, a specifically designed coupon was used to characterize the carbon diffusivity and carbide forming properties during LPC processes. Using the characterized material properties, LPC process recipes can be designed by using modeling to achieve specific case depth and surface carbon content. The work was demonstrated using Pyrowear 675 steel and DANTE commercial heat treatment modeling software.
Li, Zhichao, Fetty, Jason, Sims, Justin, Ferguson, Lynn, Baker, Treven
Designs to Dye for: Autonomy's New-Materials Revolution19AVEP05_055/1/2019
From pineapples to bacteria, Envisage's research is focused on new mobility's ‘inside’ story. Evolving vehicle engineering constantly reshapes vehicle architectures. But along with electrified drive-trains and autonomous capabilities is the need for a mindset shift in materials, opening the way for new sustainable solutions in color, materials and finish (CMF). Future cabins could have pineapple, banana, coconut and eucalyptus among the material solutions-with bacteria playing a potentially positive role. All these sources are at play for research designer Sammie Mayers-Nissen and her colleagues at Envisage, the U.K.-based specialist engineering services provider helping to find sustainable alternatives to plastic, leather and harmful dyes that still meet quality, durability and cost demands. “As always, in terms of R&D of alternative materials and color, production-cost consideration is the massive driver, with performance very close behind,” said Mayers-Nissen.
Birch, Stuart
FITTING, PORT PLUG AND BLEEDERAS5169B (Historical)3/28/2019
G-3, Aerospace Couplings, Fittings, Hose, Tubing Assemblies
Nickel Alloy, Corrosion and Heat-Resistant, Powder for Additive Manufacturing, 47.5Ni - 22Cr - 1.5Co - 9.0Mo - 0.60W - 18.5FeAMS7008 (Current)3/26/2019
This specification covers a corrosion and heat-resistant nickel alloy in the form of pre-alloyed powder.
AMS AM Additive Manufacturing Metals
Nickel Alloy, Corrosion and Heat-Resistant, Powder for Additive Manufacturing, 60Ni - 22Cr - 2.0Mo - 14W - 0.35Al - 0.03LaAMS7013 (Current)1/3/2019
The intended upper bound of this specification is that the particle size distribution (PSD) of powders supplied shall be <60 mesh (250 µm) and that no powder (0.0 wt.%) greater than 40 mesh (425 µm) is allowed.
AMS AM Additive Manufacturing Metals
New Catalyst for Plastic Production Also Creates HydrogenTBMG-3339012/1/2018
Researchers have developed a new, low-cost catalyst for plastic production that turns a biorefinery product into a starting material for the synthesis of plastics, which could represent a sustainable alternative to widespread PET. At the same time, hydrogen can also be formed during the reaction.
Electronic Capsule Measures Gases in the GutTBMG-3324311/1/2018
An electronic capsule that measures gases in the gut to revolutionize the diagnosis of gut disorders could be available within four years, following an agreement between RMIT and Atmo Biosciences.
“Soft Hardware” Cloth Has Built-In Electronic DevicesTBMG-3311310/1/2018
Optical fibers have been traditionally produced by making a cylindrical object called a preform — essentially, a scaled-up model of the fiber — and then heating it. Softened material is then drawn or pulled downward under tension and the resulting fiber is collected on a spool.
Numerical Investigation on Effects of Combustion Chamber Structure and Oxygen Enriched Air on Combustion and Emission Characteristics of Marine Diesel Engine2018-01-17869/10/2018
In order to improve the combustion and emissions for high-speed marine diesel engines, numerical investigations on effects of different combustion chamber structures combined with oxygen enriched air have to be conducted. The study uses AVL Fire code to establish three-dimensional combustion model and simulate the in-cylinder flow, air-fuel mixing and combustion process with the flow dynamics metrics such as swirl number and uniformity index, analyze the interactional effects of combustion chamber structures and oxygen enriched air against the experimental data for a part load operation at 1350 r/min, find the optimized way to improve engine performance as well as decrease the NOx and soot emissions. The novelty is that this study is to combine different oxygen concentration with different combustion chamber structures including the re-entrant chamber, the straight chamber and the open chamber. Results show that the chamber diameter, bowl depth, oxygen enrichment can greatly influence in-cylinder flow, the re-entrant chamber makes a higher power output at the price of a smaller increase of NOx emissions, meanwhile the chamber combined with suitable oxygen concentration can enhance the in-cylinder peak pressure and temperature, decrease the soot emissions and cause more NOx emissions. The straight chamber has lower emissions at the same output power level compared with the prototype, the open chamber is found to have a lower output power.
Zhao, Changpu, Huang, Sirui, Wang, Ke
Molybdenum Alloy Bars 0.48Ti - 0.09Zr - 0.02C Arc Cast, Stress RelievedAMS7819E (Current)8/14/2018
This specification covers an arc-cast molybdenum alloy in the form of round bars 0.125 to 4.5 inches (3.00 to 112.50 mm), inclusive.
AMS G Titanium and Refractory Metals Committee
Titanium Alloy, Sheet 6Al - 2Sn - 2Zr - 2Mo - 2Cr - 0.15Si AnnealedAMS4898E (Historical)8/8/2018
This specification covers a titanium alloy in the form of sheet in nominal thicknesses 0.016 through 0.1874 inch (0.41 through 4.760 mm).
AMS G Titanium and Refractory Metals Committee
Self-Powered Paper Patch Measures GlucoseTBMG-324908/1/2018
The most common methods for glucose self-testing involve monitoring glucose levels in blood. These conventional measurements are not suitable for preventing hypoglycemia during exercise. The underlying process relies on invasive and inconvenient blood sampling, which can cause skin irritation with perspiration containing electrolytes and proteins. In addition, blood testing requires that diabetics keep testing equipment such as lancets, alcohol, and a glucometer with them during exercise.
Nickel Alloy, Corrosion and Heat-Resistant, Powder for Additive Manufacturing, 62Ni - 21.5Cr - 9.0Mo - 3.65NbAMS7001 (Current)6/8/2018
This specification covers a corrosion and heat-resistant nickel alloy in the form of pre-alloyed powder.
AMS AM Additive Manufacturing Metals
Compact Termination for Structural Soft GoodsTBMG-290336/1/2018
Space environments are particularly harsh for the high-strength fibers NASA relies on for soft structures. Kevlar, Nomex, Nylon, and other synthetic fibers are broken down by exposure to the combination of vacuum, atomic oxygen, and ultraviolet radiation. Glass fiber offers unique advantages for structural applications, but is hampered by a sensitivity to bend radius and large sewn areas in order to distribute loads appropriately. The goal of this project was to determine the geometric limits of a potted end termination, and to assess weight and volume savings over a traditional sewn pin and clevis termination.
Implantable Islet Cells Come with Their Own Oxygen SupplyTBMG-291046/1/2018
Since the 1960s, researchers have been interested in the possibility of treating type 1 diabetes by transplanting islet cells — the pancreatic cells that are responsible for producing insulin when blood glucose concentration increases.
Mechanisms of Enhanced Reactivity with Ozone Addition for Advanced Compression Ignition2018-01-12494/3/2018
Mechanisms responsible for enhanced charge reactivity with intake added ozone (O3) were explored in a single-cylinder, optically accessible, research engine configured for low-load advanced compression ignition (ACI) experiments. The influence of O3 concentration (0-40 ppm) on engine performance metrics was evaluated as a function of intake temperature and start of injection for the engine fueled by iso-octane, 1-hexene, or a 5-component gasoline surrogate. For the engine fueled by either the gasoline surrogate or 1-hexene, 25 ppm of added O3 reduced the intake temperature required for stable combustion by 65 and 80°C, respectively. An ultraviolet (UV) light absorption diagnostic was also used to measure crank angle (CA) resolved in-cylinder O3 concentrations for select motored and fired operating conditions. The O3 measurements were compared to results from complementary 0D chemical kinetic simulations that utilized detailed chemistry mechanisms augmented with O3 oxidation chemistry. From the measurements, rapid thermally induced O3 decomposition was observed during the compression stroke shortly before top dead center (TDC). Ozone decomposition advanced when the charge temperature was increased, oxygen concentration was reduced, or fuel was added. While the model well captures the experimental trends, for unfueled conditions the temporal prediction of O3 decomposition is generally too far retarded. The modeling further indicates the O3 decomposition leads to a burst of highly reactive atomic oxygen (O). For fueled conditions, the O rapidly abstracts fuel hydrogen to form hydroxyl (OH), which then leads to the substantial formation of hydroperoxyl (HO2) and hydrogen peroxide (H2O2). Strong UV light absorbance shortly after O3 decomposition confirms the presence of these species in the experiments. The in situ measurements are expected to aid kinetic model development of O3 decomposition processes and the associated influence of formed radicals on autoignition kinetics.
Ekoto, Isaac, Foucher, Fabrice
Modelling the Variation in Precious Metal Dispersion in a Three Way Catalytic Converter after Aging2018-01-09594/3/2018
With emission legislations becoming ever more stringent, there is an increased pressure on after-treatment systems and more specifically three-way catalysts. With recent developments in emission legislations, there is a requirement for more complex after-treatment systems and understanding of the aging process. Whilst the body of understanding on catalyst deactivation and, in particular, catalyst aging is growing, there are still significant gaps in understanding, particularly how real world variations in temperature, flow rate and gas concentrations affect catalyst behavior. Under normal driving conditions, the catalyst can experience varying oxygen concentrations, such as under heavy acceleration or cruising down a hill will show a variation in oxygen from the engine emissions. The effect that varying oxygen concentrations has on the rate of aging is not fully understood and hence the total deactivation and conversion efficiencies are not known throughout the catalyst lifetime. Traditionally, catalyst specification has relied heavily on catalyst testing over a wide range of mileage, with catalyst aging being conducted via vehicle/bench testing, focusing on 3 main parameters; flow (space velocity), temperature (inlet/bed) and lambda (oxygen concentration). The main drawback of this approach, particularly in the early stages of powertrain development, is the cost and resource required to conduct the testing. It is in this area of development that a kinetic model to predict the catalyst performance taking into account aging time, temperature, flow rate and exposure to oxygen concentration would be of great benefit. This paper presents a continuation of previous work into the investigation of the effect of varying oxygen concentration on the rate of catalyst aging. A number of commercially available palladium three-way catalysts were aged over a precise temperature cycle at varying oxygen concentrations for different aging times related back to a mileage. The results were analyzed in detail and fed into a catalyst model in which a built in optimizer calculated the initial pre-exponential and activation energy for characterization tests. Once optimized, the model then calculated the variation in dispersion for the catalysts aged under varying levels of oxygen at a range of set mileage. The variation in dispersion over aging is presented and compared with predictions based on the standard aging algorithm and with others proposed in literature.
Irwin, Kurtis, Douglas, Roy, Stewart, Jonathan David, Pedlow, Andrew, Woods, Andrew
A New Catalyzed HC Trap Technology that Enhances the Conversion of Gasoline Fuel Cold-Start Emissions2018-01-09384/3/2018
Passive in-line catalyzed hydrocarbon (HC) traps have been used by some manufacturers in the automotive industry to reduce regulated tailpipe (TP) emissions of non-methane organic gas (NMOG) during engine cold-start conditions. However, most NMOG molecules produced during gasoline combustion are only weakly adsorbed via physisorption onto the zeolites typically used in a HC trap. As a consequence, NMOG desorption occurs at low temperatures resulting in the use of very high platinum group metal (PGM) loadings in an effort to combust NMOG before it escapes from a HC trap. In the current study, a 2.0 L direct-injection (DI) Ford Focus running on gasoline fuel was evaluated with full useful life aftertreatment where the underbody converter was either a three-way catalyst (TWC) or a HC trap. A new HC trap technology developed by Ford and Umicore demonstrated reduced TP NMOG emissions of 50% over the TWC-only system without any increase in oxides of oxygen (NOx) emissions. Other HC trap technologies had at best a 25% NMOG emission reduction. Parallel laboratory reactor studies were conducted in an effort to understand the improved trapping and NMOG combustion features of the newly developed HC trap. Increased trapping efficiency of certain aromatics (toluene) and alkenes (2-methylpropene) was assigned to rapid and efficient polymerization of these species due to a combination of strong Brønsted acidity, precious metal (i.e., Pd), and base redox active metals. During the emissions desorption phase, the combustion of the adsorbed NMOG occurred without gas-phase oxygen due to the delayed desorption of the large NMOG molecules coupled with the high activity of the base redox active metal in the presence of steam. Besides acting as a source of oxygen during combustion, the ion-exchanged form of the base metal also stabilized Pd against sintering during the hot, four-mode aging process.
Lupescu, Jason, Xu, Lifeng, Jen, Hung-Wen, Harwell, Amy, Nunan, John, Alltizer, Chad, Denison, Gregory
Cobalt Oxygen-Evolving Catalysts for Clean Solar FuelTBMG-287124/1/2018
By splitting a water molecule into two atoms of hydrogen and one of oxygen, scientists can use the Sun’s energy to make a clean fuel. Splitting a water molecule requires a metal catalyst to get the reaction started. Recently, much scientific attention has focused on cobalt, a relatively abundant and inexpensive catalyst that — in the right circumstances — can serve as an escort to an electronic connection between hydrogens and oxygens.
A Mechanistic Analysis of Oxygen Vacancy Driven Conductive Filament Formation in Resistive Random Access Memory Metal/NiO/Metal Structures18AERP02_092/1/2018
Study could lead to more efficient electrically switchable resistive random access memory devices. Air Force Research Laboratory, Wright-Patterson Air Force Base, Dayton, Ohio Resistive Random Access Memory (RRAM) devices have drawn much interest in the last decade, particularly the concept of a memristor. In this case, the so-called memristance, which provides the relationship between the change in charge (time integral of the current) and flux (time integral of the voltage), is not a constant as in linear elements, but a function of the charge, resulting in a nonlinear circuit element. Applications of such two-terminal electrical devices that provide high densities and low-power operation include, for instance, neuromorphic-type computing elements. This area of research led to a study on the effects of ionizing radiation on such devices. Significant focus on filamentary- type resistive switching (RS) mechanisms emerged, where formation/rupture of a conductive filament (CF) ensures successive switching in the nonvolatile metal-insulator-metal (MIM) memristors, dependent on the switching material. In such a RRAM device, binary oxide MIM structures are constructed using an insulating layer stacked between two electrodes, which can be built either symmetrically or asymmetrically using the same or different top or bottom electrodes, respectively.
Tech Briefs April 201818AERP022/1/2018
Multi-Domain Command and Control (MDC2) Changing the Face of Modern Warfare Loop Thermosyphons Gravity-Driven Two-Phase Cooling for the 21st Century CompactPCI Serial Space A New Embedded System Specification Takes on Extreme Environments Plain Bearings for Aerospace Applications Additive Manufacturing Materials for RF Components NASA CubeSats: Pushing the Boundaries of Technology Content Addressable Memory (CAM) Technologies for Big Data and Intelligent Electronics Enabled By Magneto-Electric Ternary CAM New associative memory approach based on the propagation of spikes provides ultra-low energy search operations. Natural DNA-Based Nonvolatile Resistive Switching Memory Reliable memory devices can be realized within a single macromolecule based on natural DNA. A Mechanistic Analysis of Oxygen Vacancy Driven Conductive Filament Formation in Resistive Random Access Memory Metal/NiO/Metal Structures Study could lead to more efficient electrically switchable resistive random access memory devices. pH-Dependent Spin State Population and 19F NMR Chemical Shift Via Remote Ligand Protonation in An Iron(II) Complex An FeII complex that features a pH-dependent spin state population demonstrates potential as a 19F chemical shift-based pH sensor.
Compact Cooling for Superconducting Single-Photon DetectorsTBMG-281241/1/2018
A new form of compact cooling technology developed for space astronomy could pave the way for use of advanced superconducting detectors for better cancer treatments, driverless cars, and practical quantum communications.
Extrusion Method Improves Structural Properties of MagnesiumTBMG-281721/1/2018
Magnesium is 75 percent lighter than steel, 33 percent lighter than aluminum, and is the fourth most common element on Earth behind iron, silicon, and oxygen. But despite its light weight and natural abundance, automakers have been halted in their attempts to incorporate magnesium alloys into structural car parts. To provide the necessary strength has required the addition of costly rare elements such as dysprosium, praseodymium, and ytterbium.
Ultrathin Semiconductor Materials “Rust” to Insulate CircuitryTBMG-2798212/1/2017
Silicon has several qualities that have led it to become the bedrock of electronics. One is that it features a very good “native” insulator — silicon dioxide, or silicon rust. Exposing silicon to oxygen during manufacturing gives chip makers a way to isolate their circuitry. Other semiconductors do not “rust” into good insulators when exposed to oxygen, so they must be layered with additional insulators — a step that introduces engineering challenges. Two new ultrathin materials share that trait, making them promising materials for electronics of the future.
Simultaneous Measurement of the Flame Lift-Off Length on Direct Injection Diesel Sprays Using High Speed Schlieren Imaging and OH Chemiluminescence2017-01-230710/8/2017
Lift-off length is defined as the distance from injector hole to the location where flame stabilized on a high injection pressure direct injection (DI) diesel spray. In this paper we used the high-speed (40 kHz) Schlieren and time-averaged OH chemiluminescence imaging technique to simultaneously measure the flame lift-off locations on a DI diesel spray in an optically accessible and constant-volume combustion vessel. The time-resolved development of the diesel spray acquired from the high-speed Schlieren imaging system enabled us to observe the instantaneous spray structure details of the spray flames. The OH chemiluminescence image obtained from a gated, intensified CCD video camera with different delay and width settings was used to determine the quiescent lift-off length. Experiments were conducted under various ambient temperatures, ambient gas densities, injection pressures and oxygen concentrations. From the Schlieren images of the injecting procedure, along the axis of the spray from the injector hole, a distinct expansion located in the downstream, after which the edge of the spray changed to transparent gradually and the refractive index gradients started to diminish. This point was defined as the flame location of high-speed Schlieren and the length from it to the injector was employed as the lift-off length. It is found that the Schlieren imaging lift-off length fluctuated within a certain range during the injection process, and the average lift-off length of quiescent conditions was also measured based on the OH chemiluminescence image. The results of the high-speed Schlieren imaging coincided well with the lift-off length results acquired from the CCD results, indicating high-speed Schlieren imaging technique can be used to measure the flame lift-off length on DI diesel spray.
Wei, Yijie, Li, Tie, Wang, Bin, Shi, Weiquan
Evaluation of the Stability and Ignition Quality of Diesel-Biodiesel-Butanol Blends2017-01-232010/8/2017
FAME is the most common renewable component of conventional automotive diesel. Despite the advantages, biodiesel is more susceptible to oxidative deterioration and due to its chemical composition as well as its higher affinity to water, is considered to be a favorable substrate for microorganisms. On the other hand, apart from biodiesel, alcohols are considered to be promising substitutes to conventional diesel fuel because they can offer higher oxygen concentration leading to better combustion characteristics and lower exhaust emissions. More specifically, n-butanol is a renewable alcohol demonstrating better blending capabilities and properties when it is added to diesel fuel, as its composition is closer to conventional fuel, when compared ethanol to for example. Taking into consideration the alleged disinfectant properties of alcohols, it would be interesting to examine also the microbial stability of blends containing n-butanol in various concentrations. Based on the aforementioned, the aim of this study is to investigate the effect of n-butanol in diesel/ biodiesel blends on fuel quality characteristics (ignition quality, lubricity) while the oxidation and microbial stability is also assessed. Blends of automotive diesel with a commercial FAME up to 20% v/v and n-butanol at concentrations of 5% and 10% v/v were prepared. The microbial stability of diesel/biodiesel/n-butanol blends was assessed and compared to diesel-biodiesel ones by preparing and storing laboratory-scale contaminated microcosms. Overall, ULSD/FAME/n-butanol ternary blends demonstrated high blending stability while density, viscosity, CFPP and sulfur content have not been substantially affected. The poor lubricity of n-butanol and ULSD was compensated by the presence of FAME. N-butanol contributed in increasing the stability - either oxidation or microbial - of the ternary blends compared to the respective binary B7 and B20 blends. Nevertheless, FAME and n-butanol have poor ignition quality characteristics, which resulted in a significant decrease of the DCN of the base fuel.
Dodos, George S., Tsesmeli, Chrysovalanti E., Zahos-Siagos, Iraklis, Tyrovola, Theodora, Karonis, Dimitrios, Zannikos, Fanourios
Measurement of Soot Concentration in a Prototype Multi-Hole Diesel Injector by High-Speed Color Diffused Back Illumination Technique2017-01-225510/8/2017
A prototype multi-hole diesel injector operating with n-heptane fuel from a high-pressure common rail system is used in a high-pressure and high-temperature test rig capable of reaching 1100 Kelvin and 150 bar under different oxygen concentrations. A novel optical set-up capable of visualizing the soot cloud evolution in the fuel jet from 30 to 85 millimeters from the nozzle exit with the high-speed color diffused back illumination technique is used as a result of the insertion of a high-pressure window in the injector holder opposite to the frontal window of the vessel. The experiments performed in this work used one wavelength provide information about physical of the soot properties, experimental results variating the operational conditions show the reduction of soot formation with an increase in injection pressure, a reduction in ambient temperature, a reduction in oxygen concentration or a reduction in ambient density.
Payri, Raul, Gimeno, Jaime, Cardona, Santiago, Ayyapureddi, Sridhar
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