Browse Topic: Gases

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Automated Gaseous Nitrocarburizing Controlled by PotentialsAMS2759/12C (Current)11/10/2025
This specification covers the requirements for producing a continuous white layer with controlled extent of porosity by means of a gaseous process, automatically controlled to maintain set values of the nitriding and carburizing potentials that determine properties of the nitrocarburized surface. Automatic control is intended to ensure repeatability of nitrogen and carbon content of the white layer which influences properties such as wear and corrosion resistance, ductility and fatigue strength.
AMS B Finishes Processes and Fluids Committee
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
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
Electrocoat Compatibilities of Automotive SealersJ1969_202101 (Current)1/7/2021
This SAE Recommended Practice sets forth a method for determining the compatibility of automotive sealers with cathodic electrocoat primer.
Materials, Processes and Parts Council
New Coating Process Lights Porous Electronics and SensorsTBMG-373648/1/2020
Researchers have shown how to coat glass and plastic with porous titanium dioxide. The fabrication process is straightforward, the materials are cheap, and the ceramic’s gas sensing performance is considerably improved compared with current devices.
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
First-Principles Research on Adsorption of NOx on Pt Cluster and BaO Cluster Supported by γ-Al 2 O 3 (110) Surface2020-01-03574/14/2020
Lean NOx trap (LNT) is a great potential NOx abatement method for lean-burn gasoline engines in consideration of exhaust aftertreatment cost and installation space. NOx firstly is adsorbed on storage sites during the lean-burn period, then reduced to N2 under catalysis of the catalyst sites in the rich-burn phase. There must be a spillover of NOx species between both types of sites. For a better understanding of this spillover process of NOx species between Pt (as the catalytic center) and BaO sites (as storage components in commercial catalyst), this work focused on the vital first step of spillover, the adsorption of NOx on clean substrate surface (γ-Al2O3 (110) surface) and Ba\Pt cluster supported by the surface. Based on first principles software VASP (Vienna Ab-initio Simulation Package), the most stable adsorption structures of NO with Pt3 clusters and (BaO)3 clusters on carrier γ- Al2O3 (110) surface were confirmed and the adsorption energy of these structures were compared. Meanwhile electronic structure analysis of these adsorption systems was investigated by analyzing DOS (density of state), Bader charge, charge density difference and COHP (crystal orbital Hamilton population). From electronic structure analysis methods mentioned above, a better view of electron transfer and bond formation between gas phase NOx molecules and supported BaO or Pt cluster was obtained. This work has laid a good foundation for the further research of NOx adsorption and reduction of LNT by providing a more microscopic explanation of NOx species spillover mechanism.
Li, Shilong, Zhang, Yanke, zhao, Jin
Wearable Gas Sensor Enhances SensitivityTBMG-362443/1/2020
A highly sensitive wearable gas sensor for environmental and human health monitoring may soon become commercially available, according to researchers at Penn State and Northeastern University.
Research Zeroing in on Electronic Nose for Diagnosing DiseaseTBMG-362603/1/2020
Research at Oregon State University has pushed science closer to developing an electronic nose for monitoring air quality, detecting safety threats and diagnosing diseases by measuring gases in a patient’s breath.
Researchers Generate Terahertz Laser with Laughing GasTBMG-361473/1/2020
Terahertz waves have frequencies higher than microwaves and lower than infrared and visible light. Where optical light is blocked by most materials, terahertz waves can pass straight through, similar to microwaves. If they were fashioned into lasers, terahertz waves might enable “T-ray vision,” with the ability to see through clothing, book covers, and other thin materials. Such technology could produce crisp, higher-resolution images than microwaves, and be far safer than X-rays.
Threads Detect Gases When Woven into ClothingTBMG-359892/1/2020
A fabrication method was developed to create dyed threads that change color when they detect a variety of gases. The threads can be read visually or even more precisely by use of a smartphone camera, to detect changes of color due to analytes as low as 50 parts per million. Woven into clothing, the gas-detecting threads could provide a reusable, washable, and affordable safety asset in medical, workplace, military, and rescue environments.
The Influence of the Content and Nature of the Dispersive Filler at the Formation of Coatings for Protection of the Equipment of River and Sea Transport05-13-01-00061/23/2020
To protect ship equipment of river and sea transport, it is suggested to use polymeric protective coatings based on epoxy diane oligomer ED-20, polyethylene polyamine (PEPA) curing agent and filler, which is a departure from industrial production. Thus the purpose of the work is analysis of major dependency of the properties on the content of fillers that allowed to revealed the critical filler content (furnace black) in composites to form a protective coating with the required set of characteristics. The infrared (IR) spectral analysis was used to investigate the presence of bonds on the surface of particles of the PM-75 furnace black, which allows us to assess the degree of cross-linking of the polymer. The influence of the content of dispersed furnace black on the physicomechanical and thermophysical properties and the structure of the protective coating is investigated. For the formation of the coating with increased adhesive properties, the optimum content of the additive is q = 25 parts by weight (pts.wt.), due to the increase in the number of C—O, C—C, C═O, C═C, C═O, and O═C—H bonds. For the formation of the coating with increased cohesive properties, the optimum content of the additive is q = 20 pts.wt., which is associated with the maximum compaction of the polymer spatial net. On the basis of the analysis of the surface of the composite fracture, a homogeneous topology of the fracture surface was found which characterizes the viscous state of material destruction at the content of the additive q = 5 pts.wt., which provides significant improvement of the physical and mechanical properties of the materials developed. Additionally, it was found that when the PM-75 particles were introduced at the content of q = 10-30 pts.wt., the uniformity of the structure is retained, but its abnormal similarity is observed. This allowed us to determine the optimal content of the additive (q = 20 pts.wt.) for the formation of coatings with high cohesive strength in the complex.
Sapronov, Oleksandr, Buketov, Andriy, Sapronova, Anna, Sotsenko, Vitalii, Brailo, Mykola, Yakushchenko, Serhii, Maruschak, Pavlo, Smetankin, Serhii, Kulinich, Andriy, Kulinich, Viacheslav, Poberezhna, Liubov
Embedded Gas and Temperature Sensors for Extreme EnvironmentsTBMG-358291/1/2020
Innovative process control systems for improved efficiency and lower emissions in current and future fossil-fuel-based power systems and related applications require durable, embedded sensor technology that can operate at higher temperatures and in harsh conditions.
Q&A: Refrigeration by Twisting FibersTBMG-3571312/1/2019
Dr. Ray Baughman, Director of the Alan G. MacDiarmid Nano Tech Institute at the University of Texas, Dallas, and his team discovered a new technology for refrigeration that is based on twisting and untwisting fibers.
Innovations in Orthopedic Elastomers Enhance Durability and AppearanceTBMG-3562512/1/2019
The history of silicone rubber is synonymous with advancements in medical materials. Silicones, a family of biocompatible elastomers, provide an attractive balance of properties. For example, silicones offer thermal stability over a wide temperature range. They also provide electrical insulation and are resistant to ozone, water, ultraviolet (UV) light, and some chemicals. For medical applications, silicone rubber can also meet requirements from the U.S. Food and Drug Administration (FDA) and the U.S. Pharmacopeia (USP).
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
The Challenge of Replacing Hard Chrome19AERP10_0310/1/2019
The search for a suitable replacement for hard chrome on aerospace components has been a key supply chain priority for aircraft manufacturers. This is because of the documented health risks to workers and the impact on the environment from exposure to hexavalent chromium, a carcinogen that occurs during the chrome plating process and is the most toxic form of chromium. As a result, chromium is a highly regulated chemical in major markets worldwide. In the European Union, hexavalent chromium falls under the domain of the EU regulation, REACH (Registration, Evaluation, Authorization and Restriction of Chemicals), which establishes guidelines for the safe use of chemicals throughout the supply chain. Chromium is also closely regulated in the United States by OSHA.
Products of Tomorrow: October 2019TBMG-3528610/1/2019
This column presents technologies that have applications in commercial areas, possibly creating the products of tomorrow. To learn more about each technology, see the contact information provided for that innovation.
The Challenge of Replacing Hard ChromeTBMG-3535910/1/2019
The search for a suitable replacement for hard chrome on aerospace components has been a key supply chain priority for aircraft manufacturers. This is because of the documented health risks to workers and the impact on the environment from exposure to hexavalent chromium, a carcinogen that occurs during the chrome plating process and is the most toxic form of chromium.
Deployable Emergency Shutoff Device Blocks High-Velocity Fluid FlowsTBMG-349318/1/2019
NASA's Marshall Space Flight Center has developed a device and method for blocking the flow of fluid from an open pipe. The device plugs, controls, and meters the flow of gases and liquids. Anchored with friction fittings, spikes, or explosively activated fasteners, the device is well-suited for harsh environments and high fluid velocities and pressures. With the addition of instrumentation, it can also be used as a variable-area flow metering valve that can be set based upon flow conditions. With robotic additions, it can be configured to crawl into a pipe and then anchor and activate itself to block or control fluid flow.
Groove Design - Metal Face SealAIR1108A (Current)6/6/2019
Groove designs presented herein are applicable for use with machined or formed metal seals which are similar in configuration to those shown in figure 3, which operate under internal pressure or in vacuum service and which have been specifically qualified or recommended by the purchaser or the manufacturer for use with this AIR. They are also applicable for use with metal o-rings (e.g., MS9142, MS202 thru MS9205) where interchangeability with machined or formed metal seals is desired. For metal o-ring groove designs where inter-changeability is not a requirement refer to ARP 674.
E-25 General Standards for Aerospace and Propulsion Systems
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
Temperature-Controlled MaterialsTBMG-344405/1/2019
Researchers have designed a temperature-controllable copper-based material for sieving or storing different kinds of gases. The rationale used to design the material could act as a blueprint for developing nano-porous materials with a wide variety of applications, including medical.
Study on Improvement of NOx Reduction Performance at Low Temperature Using Urea Reforming Technology in Urea SCR System2019-01-03174/2/2019
To reduce NOx and PM emissions in exhaust gas, after-treatment systems for low NOx emissions are being developed in combination with improvements of engine combustion. In recent years, the exhaust gas temperature has been dropping because of enhanced low-fuel consumption of the engine. Therefore, it is urgent to develop NOx reduction technologies that work at a low temperature under 200degC. Since NOx is reduced by reacting with ammonia supplied to the SCR catalyst, it is necessary to make the urea solution decompose into ammonia using the heat of the exhaust gas to supply sufficient ammonia to the SCR catalyst. However, both the decomposition reaction and hydrolysis reaction of the urea have insufficient exhaust heat, thus making it difficult for urea to decompose and hydrolyze to ammonia at a low temperature. To solve this problem, it focuses on forcibly decomposing the urea solution without depending on the exhaust gas temperature. We selected a urea reforming method in which the urea is directly heated using the glow plug as the heat source. In this study, we have considered further improvement of the NOx reduction performance at a low temperature with a view to improving the ammonia generation efficiency by urea reforming.
Okada, Yuichi, Hirabayashi, Hiroshi, Sato, Shinya, Inoue, Hiroshi
Numerical Modeling Study of Detailed Gas Diffusivity into Catalyst Washcoat for Lean NOx Catalyst2019-01-09934/2/2019
To evaluate the relationship between the exhaust gas purification performance and the catalyst pore properties related to gas diffusion, an elementary reaction model was combined with gas diffusion into catalyst pores, referred to as the pseudo-2D gas diffusion/reaction model. It was constructed for Pt/Al2O3 + CeO2 catalyst as lean NOx catalyst. The gas diffusion was described as macro pore diffusion between the catalyst particles and meso pore diffusion within the particle. The kinetic model was composed of 26 reactions of NO/CO/O2 chemistry including 17 Pt/Al2O3 catalyst reactions and 9 CeO2 reactions. Arrhenius parameters were optimized using activity measurement results from various catalysts with various pore properties, meso pore volume and diameter, macro pore volume and diameter, particle size, and washcoat thickness. Good agreement was achieved between the measured and calculated values. Moreover, as compared to the performance of other catalysts which was not used for reaction model calibration, the simulated results were in good agreement with this experimental data. Using the calibrated reaction model combined with detailed gas diffusion model, a sensitivity analysis for NOx concentration was performed to identify key diffusion parameters of the lean NOx catalyst. In summary, parameters with the highest sensitivity were catalyst particle size, washcoat thickness, CeO2 meso pore volume, and diameter. Also, catalyst macro pore volume and diameter showed no dependence. Consequently, to increase the NOx purification performance, the meso pore parameters and washcoat thickness should be increased, particle size should be decreased. With these changes, the gaseous NOx will easily move to the catalyst surface and into the active site of meso pore, resulting in better performance.
Yamamoto, Osami, Matsuo, Yuichi, Tosa, Shinichi, Okayama, Tatsuya, Zhang, Zhiwei, Tolsma, John
Q&A: Professor Jaime Grunlan, Texas A&M University, College Station, TXTBMG-341414/1/2019
Professor Grunlan and his team are developing a new flame-retardant coating using renewable, nontoxic materials readily found in nature that could provide effective fire protection for several widely used materials.
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
Effects of Isotopic Calibration Gases on IR Quantification Analyzer Techniques to Measure CO and CO 2 in Engine Emissions Testing2019-01-00761/15/2019
Infrared spectroscopic methods are the most common methods in the automotive industry for measuring carbon monoxide (CO) and carbon dioxide (CO2) gases. Concentrations of both gases, which are emitted from the combustion of fuels, are required to be determined accurately in order to follow strict environmental regulations. Appropriate analytical techniques and accurate calibration gas mixtures are therefore critical for successful measurements. Regulatory documents such as the EPA’s Code of Federal Regulations 40 (CFR 40) part 1065.250, UN ECE-R83, and (EU) 2017/1151 recommend a nondispersive infrared (NDIR) analyzer to measure CO and CO2 concentrations in raw or diluted exhaust gas samples. Over the last decade, Fourier Transform Infrared (FTIR) spectrometry has been validated and recommended in engine exhaust certification testing as well as in engine and vehicle development activities. The variation in the isotopic ratio of 13C/12C in natural atmospheric CO2 is in the range of ± 2‰ however, artificial or non-natural sources of CO or CO2 can potentially have much larger variances. To fully understand the impacts of isotopic composition on the analyzers, the δ13C values used in this study were selected to cover a broad range of non-natural isotope ratios (very depleted and enriched). In the present work on both FTIRs and NDIRs, up to 4% deviation in analytical results were observed relative to the base case composition (-12‰ 13CO) when the CO/N2 gas mixture was enriched to 2630‰ with 13C content. Analytical deviations measured on NDIR analyzers were more pronounced (4-14%) relative to the base case composition with the change of 13C in the CO2/N2 mixture from -982‰ to 6783‰. Moreover, the error with FTIR measurements could rise up to a factor of 2 or more depending on the 13C and 12C band selection and their evaluation methods. Known isotopic gas mixtures and careful evaluation band selection in the FTIR method were observed to reduce the analytical errors. Even though calibration gases were prepared accurately for molecular concentrations, carbon isotopic concentrations far removed from natural abundance showed significant errors in the measurements. It is therefore essential to have either known or natural ratios of carbon isotope calibration gas mixtures for accurate emission measurements.
Kumar, Anuj, Arlitt, Bertold, Jacksier, Tracey
The Rotating Liner Engine (RLE) Diesel Prototype: Preliminary Testing2019-01-00841/15/2019
The Rotating Liner Engine (RLE) concept is a design concept for internal combustion engines, where the cylinder liner rotates at a surface speed of 2-4 m/s in order to assist piston ring lubrication. Specifically, we have evidence from prior art and from our own research that the above rotation has the potential of eliminating the metal-to-metal contact/boundary friction that exists close to the piston reversal areas. This frictional source becomes a significant energy loss, especially in the compression/expansion part of the cycle, when the gas pressure that loads the piston rings and skirts is high. This paper describes the Diesel RLE prototype constructed from a Cummins 4BT and the preliminary observations from initial low load testing. The critical technical challenge, namely the rotating liner face seal, appears to be operating with negligible gas leakage and within the hydrodynamic lubrication regime for the loads tested (peak cylinder pressures of the order of 80 bar).
Dardalis, Dimitrios, Hall, Matthew, Matthews, Ron, Basu, Amiyo, Ozel, Tayyar
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
Effects of Surface Preparation on Medical Silicone Adhesive PerformanceTBMG-3345312/1/2018
Medical device manufacturers often use silicone adhesives to bond parts together when assembling products such as catheters, pacemakers, cochlear implants, aesthetic implants, and gastric balloons. In addition to evaluating the different types of adhesive formulations, device manufacturers also need to critically assess several other factors in the adhesion process, including the substrates to be bonded, their surface energy, and even the overall device manufacturing process. Without addressing these factors early in the design process, medical device manufacturers risk costly delays and potential device manufacturing issues.
Sensor Combination Detects People by SmellTBMG-3337912/1/2018
Trained rescue dogs are the best disaster workers — their sensitive noses help them track down people buried by earthquakes or avalanches. But dogs need breaks. A new measuring device is always ready for use.
Detecting battery leaks at production speeds18AUTP11_0711/1/2018
Inficon has launched what it said is an industry-first, robotic-compatible leak-detection system that can use either helium or hydrogen-forming gas to ferret out minuscule cracks in the batteries of electrified vehicles. “Customers were asking for an accurate and reliable high-speed leak detector that could use both tracer gases so they could choose the lowest-cost or easiest-to-source test gas available,” said Thomas Parker, a mechanical engineer and Inficon's North American automotive sales manager. The leak detector has the same testing sensitivity with either helium or the forming gas (95% nitrogen/5% hydrogen).
Buchholz, Kami
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.
Cell-Sized Robots Sense Their EnvironmentTBMG-3323011/1/2018
Colloids — insoluble particles or molecules anywhere from a billionth to a millionth of a meter across — are so small they can stay suspended indefinitely in a liquid or even in air. Robots about the size of a human egg cell were created that can sense their environment, store data, and carry out computational tasks. They consist of tiny electronic circuits made of two-dimensional materials, piggybacking on colloids. By coupling these tiny objects to complex circuitry, the researchers hope to lay the groundwork for devices that could be dispersed to carry out diagnostic journeys through anything from the human digestive system to oil and gas pipelines, or perhaps to waft through air to measure compounds inside a chemical processor or refinery.
Enhancement of Thermal Fatigue Strength by the Addition of Calcium to Hypoeutectic Aluminum-Silicon Alloys2018-32-002710/30/2018
Several elements affect the structure of eutectic silicon in hypoeutectic aluminum alloys [1, 2, 3, 4]. Among them, calcium has been investigated to a lesser extent compared to the typically used sodium and strontium. In order to enhance the thermal fatigue strength of a small engine, the morphology of eutectic silicon in hypoeutectic aluminum-silicon alloys is controlled by the addition of calcium. In addition, the castability and mechanical properties are investigated. Hence, samples containing different amounts of calcium are prepared at different cooling rates during solidification. The results revealed that, with the increase in the calcium amount and the cooling rate, eutectic silicon exhibits a fine morphology in cross-sectional images. Particularly, with the addition of at least 62 mass ppm of calcium in a specific range of cooling rates, refined eutectic silicon is obtained. In order to clarify additional effects of the added calcium, the amount of dissolved gas, fluidity, and porosity defects are evaluated. The amount of dissolved gas and the fluidity do not change in the range of the investigated calcium amounts. However, the sizes of each of the shrinkage porosities decrease and the region where porosities generated is spread, with spread-out regions. The sample strength with refined eutectic silicon is evaluated by tension and thermal fatigue tests. Refined samples exhibit greater elongation and thermal fatigue strength compared with those of eutectic silicon with a coarse morphology. The addition of calcium leads to the effective enhancement of the mechanical properties of hypoeutectic aluminum-silicon alloys.
Watanabe, Kentaro, Motoyama, Kojiro, Watanabe, Tomokazu, Ishihara, Kazuhiro, Maeda, Fujio
Safety Analysis of an Airship Which Loses Lifting Gas from the Hull2018-01-195410/30/2018
This study investigates the physical phenomena that affect a high-altitude airship in the presence of lifting gas losses from the hull. General atmospheric thermodynamics and basic physical principles are adopted to describe the behavior of an airship with envelope failures that generate buoyant gas dispersion or depressurisation phenomena. Overpressure that could grant to maintain some controllability during a large part of the descent is assessed by mean of the thermodynamic model of the envelope in the presence of gas losses. Optimisation of the inflation parameters is provided and the conditions for avoiding dangerous crashes on the ground and the potential recovery of a damaged vehicle, people and its payload. In particular, the requirements for a slow depressurisation is computed by the equilibrium with the atmosphere and then how can it be possible to sustain controlled navigation are determined. A key factor for security relates directly to the capability of preserving some airship balloon overpressure for the longest time possible. This condition can extend much the range of control. Complete forfeit conditions will be determined to demonstrate that airship cannot be anymore controllable below 20% of the initial altitude at which the failure has started. In some cases, specific manoeuvres could allow configuring the deflated balloon as a parachute, if coupled with adequate safety systems. This research about safety conditions will also be useful for designing safety systems. A general guideline for safety systems has been defined showing that airship if well created and well governed in emergency conditions will be much safer than any other aerial vehicle.
Trancossi, Michele, Pascoa, Jose, Cannistraro, Giuseppe
Modeling of Quasi-Steady State Heat Transfer Phenomena with the Consideration of Backflow Gas Effect at Intake Manifold of IC Engines and Its Numerical Analyses on 1-D Engine Simulation2018-32-002910/30/2018
An empirical equation was developed for modeling the heat transfer phenomena taking place in an intake manifold which included the backflow gas effect. In literature, heat transfer phenomenon at intake system is modeled based on steady flow assumptions by Colburn analogy. Previously, authors developed an equation with the introduction of Graetz and Strouhal numbers, using a port model experimental setup. In this study, to further improve the empirical equation, real engine experiments were conducted where pressure ratio between the intake manifold and engine cylinder were added along with Reynolds number to characterize the backflow gas effect on intake air temperature. Compared to the experimental data, maximum and average errors of intake air temperature estimated from the new empirical equation were found to be 2.9% and 0.9%, respectively. Furthermore, Colburn analogy and suggested empirical equation were consecutively implemented to 1-D engine simulation software on gasoline and diesel engine setups. Naturally aspirated gasoline engine simulations revealed the importance of the backflow gas effect in line with the real engine experiments. Maximum and average temperature differences between the Colburn analogy and suggested equation showed 36.0 K and 28.7 K, respectively. In turbocharged diesel engine simulations, intake air temperature’s effect on auto ignition timing was analyzed. At engine speed of 2250 rpm, in-cylinder air temperature difference at IVC was found to be 5.8 K. This difference corresponded to an advanced auto-ignition timing by 1.15 deg. CA, which could be interpreted an estimated reduction of CO2 gas by 0.28%.
Yilmaz, Emir, Ichiyanagi, Mitsuhisa, Suzuki, Takashi
NH 3 Sensor Measurements in Different Engine Applications2018-01-18149/10/2018
In this study the exhaust gas ammonia (NH3) concentrations from different exhaust sources were measured with an ammonia sensor. The aim of the study was to verify whether an NH3 sensor has the potential to be used for monitoring and control purposes for SCR systems. Measurements were performed in laboratory and field conditions and comparison was made between Fourier Transform Infrared (FTIR) and Laser Diode Spectrometer (LDS) measurement techniques. With heavy-duty vehicles, a comparison between an LDS, FTIR and NH3 sensor was performed on a heavy-duty chassis dynamometer. Measurements were performed at steady speeds using a World Harmonized Vehicle Cycle (WHVC) and Braunschweig test cycles. The urea injection rate for the SCR system was varied to generate different ammonia levels in the exhaust gas. NH3 measurements with FTIR and NH3 sensor were performed on large cruise ships using heavy fuel oil (HFO) and marine gas oil (MGO) as fuels. Also, long-term trials on two cruise ships were conducted using heavy fuel oil and low sulphur (S < 0.1%) residual fuel. The results indicate that the NH3 sensor has the potential for being used in different applications for monitoring and controlling the SCR system. Measurement results with the sensor were in good correlation with LDS and FTIR techniques and, in dynamic measurements, the sensor response was very fast.
Murtonen, Timo, Vesala, Hannu, Koponen, Paivi, Pettinen, Rasmus, Kajolinna, Tuula, Antson, Olli
Study of Interaction of N-Methyl Aniline Octane Booster on Lubricating Oil2018-01-18099/10/2018
The impact of N-Methyl Aniline (NMA) octane booster on lubricating oil has previously been studied and the main findings were reported in SAE paper 2016-01-2273. Increased sludge formation had been observed in modified ACEA black sludge testing when NMA was added to the fuel but there was very limited viscosity increase, which did not corroborate the trend evidenced on modified CEC L-109 oxidation testing where significant viscosity increase was noted when NMA was added to the oil and fuel mixture. Accordingly, modified black sludge tests have been run with and without NMA added to the oil sump at the beginning of the test to better match modified L-109 oxidation bench test conditions. Results showed the same trend in terms of viscosity increase between the modified L-109 oxidation bench test and black sludge test. However, no impact on sludge formation was noted under this configuration and, in addition, no NMA could be detected in end of test samples as opposed to what has been observed when NMA was added to the fuel. This could suggest that NMA had either evaporated or reacted with lubricating oil. In order to better understand the interaction between NMA and lubricating oil to explain viscosity increase, two fully formulated oils evaluated in the previous study, as well as their respective base stock blends only, were run in modified L-109 oxidation tests in the presence of fuel only and fuel with NMA. In addition, individual additive components were added to base stock blends to study their interaction with NMA. End of test samples were then investigated using several analytical techniques such as Fourier Transformation Infra-Red, Gel Permeation Chromatography and Gas Chromatography with Nitrogen Chemiluminescence Detector. When added to base stock blends only, NMA acted as an anti-oxidant, thus limiting viscosity increase. However, when added to fully formulated oils and as previously observed, significant viscosity increase occurred, confirmed by the high molecular weight species identified by various analytical techniques. Those techniques also confirmed that NMA did not evaporate at the end of test but reacted, preferentially with dispersant and detergent additives.
Marie, Herve, Deeg, Hans Peter, Philipp, Harald, Marukos, Nicholas, Wang, Chengrong
The Use of Ozone in Low Temperature Methane Control for Natural Gas Applications2018-01-17029/10/2018
Lean operating natural gas heavy duty applications have advantages in terms of lower CO2 and PM compared to Diesel applications. This makes operating heavy duty applications on natural gas attractive and currently, they do not have to implement an exhaust particulate filter. However, the challenge is controlling methane emissions over a range of vehicle operating conditions. Methane is extremely stable and light off occurs at temperatures above 400 °C, with high efficiency occurring >500 °C and requires high precious metal loaded catalysts in the range of 150 - 200 g/ft3. Under stoichiometric conditions, 500 °C can be met in many engine operating points however, for lean operating applications, the exhaust temperature can be significantly lower than 500 °C posing a significant challenge for exhaust catalytic CH4 control. This paper will discuss synthetic gas reactor study results using ozone in the feed gas to perform low temperature methane control. A range of catalysts were characterised for the development of low temperature methane control and a non-precious metal catalyst was found to give high efficiency at low temperatures. The best catalyst screened did not contain PGM and was a current production catalyst that gave >60% CH4 control at 220 °C, in the presence of water. All other catalysts screened gave no significant methane control activity at low temperatures. The feed gas composition played a key role in the peak efficiency obtained. The data shows a significant improvement in ozone enhanced catalysis compared to more traditional precious metal based CH4 control routes.
Keenan, Matthew, Nicole, Jacques, Poojary, Damodara
Application of Genetic Algorithm for the Calibration of the Kinetic Scheme of a Diesel Oxidation Catalyst Model2018-01-17629/10/2018
In this work, a methodology for building and calibrating the kinetic scheme for the 1D CFD model of a zone-coated automotive Diesel Oxidation Catalyst (DOC) by means of a Genetic Algorithm (GA) approach is presented. The methodology consists of a preliminary experimental activity followed by a modelling, optimization and validation process. The tested aftertreatment component presents zone coating, with the front brick side covered with Zeolites in order to ensure hydrocarbons trapping at low temperature, and Platinum Group Metal (PGM), while the rear brick side presents an alumina washcoat with a different PGM loading. Reactor scale samples representative of each coating zone were tested on a Synthetic Gas Bench (SGB), to fully characterize the component’s behavior in terms of Light-off and hydrocarbons (HC) storage for a wide range of inlet feed compositions and temperatures, representative of engine-out conditions. On the modeling side, a 1D-CFD model of the component was built in GT-SUITE environment and a global kinetic scheme was defined, based on the available literature, expressed in the Arrhenius form. A Genetic Algorithm optimization tool was then used to calibrate reaction rate parameters and active sites densities, by means of a sequential calibration strategy, categorizing the reaction model into several steps according to the experimental test protocol. In each step of the calibration, the number of independent variables was reduced as much as possible and the reactions could be isolated using primary single species tests, moving then to more complex gas mixtures to calibrate the mutual interaction of different species. The model was finally validated over experimental data, showing satisfactory predictive capabilities in terms of both light-off temperatures and oxidation rates, capturing the differences between different coating types as well. The presented methodology has revealed promising advancement in the modelling and calibration of aftertreatment components, showing that GA can be used for complex problems, such as the calibration of a global kinetic scheme, with an acceptable computational effort.
Millo, Federico, Rafigh, Mahsa, Sapio, Francesco, Barrientos, Eduardo J., Ferreri, Paolo
Development of an On-Line System for Oil Void Fraction Measurements2018-01-18039/10/2018
A prototype of measurement device that compresses a sample of engine oil at constant temperature and calculates its void fraction from the magnitude of volume change and pressure was proposed. During compression, the oil sample was pressurized to several hundreds of kPa above atmospheric pressure. Because the gas can be regarded as an ideal gas at this pressure level, the estimation of void fraction can be based on a simple formula derived from the ideal gas law, the law of conservation of mass and Henry’s law. The calibration line is represented by a linear equation of the void fraction, and from the coefficient of void fraction or the constant term the volume fraction of the dissolved gas in the initial state can be known. That is, by experimentally determining the calibration line, not only void fraction but also the volume fraction of the dissolved gas in the initial state can be known. Then, the results of measurement principle confirmation tests were given. Initial tests have revealed that the output of the device is highly repeatable over a range of void fractions from 0.05 to 0.30, and sample oil temperatures from 20 °C to 95 °C. A temperature dependence of the calibration lines was observed, although the effects were found to be minimal above 40 °C, particularly at higher void fractions. Finally, the measurement void fractions of the engine oil in the passage that is diverted from the sump bottom of the running engine (motored) were showed. The void fractions were less than 0.05. Measurements of void fraction were carried out in two ways: analysis of bubbles in the engine oil image data and the proposed method.
Makita, Shinobu, Ikeda, Yuji
Effects of Clamping Force on the Operating Behavior of PEM Fuel Cell2018-01-17189/10/2018
Proton exchange membrane (PEM) fuel cell is widely recognized as an outstanding portable power plant and expected to be possibly commercialization in the near future. As is well known, mechanical stresses implemented on the bipolar plates during the assembly procedure should have prominent influences on mass and heat transfer behavior inside the cell, as well as the resultant performance. In this study, an analytical model is proposed to comprehensively investigate the influence of clamping force on the mass transport, electrochemical properties and overall cell output capability of a PEM fuel cell. The results indicate that proper clamping force not only benefits the gas leakage prevention but also increases the contact area between the neighboring components to decrease the contact ohmic resistance. However, deformation always takes place simultaneously, changing the local physical structures of the cell components, which possibly leads to the decrement of porosity and permeability of the gas diffusion layer (GDL) and catalyst layer (CL), hinders the gas species and liquid water transport in GDL, and also decreases the cross-sectional flow area in the channel. The combined effect of the aforementioned factors finally contributes to the cell performance fluctuation. Moreover, although the contact resistance decreases with increasing stresses, more significant mass transfer losses, e.g. lower membrane water content and larger gradient in liquid saturation, results in more serious concentration voltage losses and weaker proton conductivity in the membrane, further impairing the cell voltage output. Therefore, cell performance should be optimized by the balancing among the transport properties and the contact resistance involved in the fuel cell. By using this analytical model, optimal cell design parameters and clamping pressure exerted on the fuel cell can be quickly predicted accordingly. Proper discussions are carried out and suggestions are proposed.
Chen, Rouxian, Qin, Yanzhou, Du, Qing, Peng, Jun
5 Ws of a Simple Nerve Gas DetectorTBMG-328559/1/2018
First responders, soldiers, and scientists in the field.
The Ultimate ‘Smell Test’: Device Sends Rotten Food Warning to SmartphonesTBMG-328709/1/2018
When it comes to the “smell test,” the nose isn't always the best judge of food quality. Now in a study appearing in ACS’ journal Nano Letters, scientists report that they have developed a wireless tagging device that can send signals to smartphones warning consumers and food distributors when meat and other perishables have spoiled. They say this new sensor could improve the detection of rotten food, so it can be tossed before consumers eat it.
Products of Tomorrow: September 2018TBMG-328279/1/2018
This column presents technologies that have applications in commercial areas, possibly creating the products of tomorrow. To learn more about each technology, see the contact information provided for that innovation.
Artificial “Blubber” Protects Divers in Frigid WaterTBMG-324828/1/2018
When Navy SEALs carry out dives in Arctic waters, or when rescue teams are diving under ice-covered rivers or ponds, the survival time even in the best wetsuits is very limited — as little as tens of minutes. Researchers have discovered a process to triple that survival time.
Wireless Chemical Sensor and Sensing Method for Use TherewithTBMG-297007/1/2018
NASA Langley Research Center has developed a wireless, open-circuit SansEC (Sans Electrical Connections) sensor that can detect the presence of chemicals without being in contact with the chemical it is detecting. This unique thin-film sensor is used in conjunction with a chemical reactant that detects the presence of the chemical. Because of the way the sensor operates, the reactant can be separated from the sensor itself and placed in caustic or harsh environments, and can still work to detect the specific chemical it was designed to discern. The ingenuity of the thin-film design with the elimination of all wires, connections, and electronic components enables the sensors to be produced cost-effectively. This is an application of the NASA award-winning SansEC sensor, which is damage-resilient and environmentally friendly to manufacture and use. The sensors use a NASA award-winning magnetic field response recorder to provide power to the sensors and to acquire physical property measurements from them.
An Overview of Microstructural Approaches for Modelling and Improving Sound Proofing Properties of Cellular Foams: Developments and Prospects2018-01-15646/13/2018
Significant advances have been made over the last 15 years in the field of modelling the acoustic properties of foams from the description of their microstructures. It entails a multidisciplinary work at the junction between physico-chemistry and mechanics of porous media, which involves a dialogue between different disciplines and requires the joint development of several techniques (imaging, upscaling, numerical computations, and experimental identification). It seems to be of timely interest to take stock of the methodological developments that have provided guidance on how to manufacture the new generation of foams with enhanced properties and to identify possible future methodological developments.
Perrot, Camille, Hoang, Minh Tan, Chevillotte, Fabien
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