Search Results

Proof-of-concept testing was performed to determine the effectiveness of a computer controlled air pump (CCAP) in reducing the unburned hydrocarbons (UHC) and carbon monoxide (CO) emitted from automobile engines. For the initial phase of testing, a prototype CCAP was designed and evaluated on a dynamometer test-stand at the University of Tennessee. This CCAP maintained the engine's exhaust at a stoichiometric air/fuel ratio by utilizing a second oxygen sensor mounted downstream from the catalyst. In this way, the catalyst's conversion efficiency for CO and UHC was always high, even if the engine was running rich. Results of this steady-state testing indicated that the CCAP was able to reduce UHC and CO emissions without a corresponding increase in oxide of nitrogen (NOx) emissions. Additionally, catalyst temperatures did not increase dramatically.

Composite materials have the potential to reduce the overall cost and weight of automotive structures with the added benefit of being able to dissipate large amounts of impact energy by progressive crushing. To identify and quantify the energy absorbing mechanisms in composite materials, test methodologies were developed for conducting progressive crush tests on composite specimens that have simplified test geometries. The test method development focused on isolating the damage modes associated with the frond formation that occurs in dynamic testing of composite tubes. A new test fixture was designed to progressively crush composite plate specimens under quasi-static test conditions. Preliminary results are presented under a sufficient set of test conditions to validate the operation of the test fixture.

AFR, Inc. is developing a multifunctional Carbon material that, in addition to excellent radiation shielding characteristics, is appropriate for certain energy storage applications. As an excellent Hydrogen gas sorbent, it increases the usable storage capacity of a gas cylinder by ∼25% at 3500 PSI and by ∼150% at 500 PSI. Our ongoing NASA Langley funded study shows that when a sorbent-filled tank is charged with hydrogen, it provides shielding superior to polyethylene against most types of ionizing particles. Even as hydrogen is consumed, the carbon and tank ensure that significant radiation shielding capability is maintained. In addition to storing hydrogen, the carbon material also displays considerable strength. In this paper, we explore some of its mechanical properties that show this material is very versatile and highly multifunctional.

Lunar dust exposures occurred during the Apollo missions while the crew was in the lunar module on the moon's surface and especially when micro-gravity conditions were attained during rendezvous in lunar orbit. Crews reported that the dust was irritating to the eyes, and in some cases, respiratory symptoms were elicited. NASA's current vision for lunar exploration includes stays of 6 months on the lunar surface hence the health effects of periodic exposure to lunar dust in the habitat need to be assessed. NASA is performing this assessment with a series of in vitro and in vivo tests with authentic lunar dust. Our approach is to “calibrate” the intrinsic toxicity of lunar dust by comparison to a relatively low toxicity dust (TiO2) and a highly toxic dust (quartz) using intrapharyngeal instillation of the dusts to mice. A battery of indices of toxicity is assessed at various time points after the instillations.

The addition of metal nanoparticles to standard coolant fluids dramatically increases the thermal conductivity of the liquid. The properties of the prepared nanofluids will allow for lighter, smaller, and higher efficiency spacecraft thermal control systems to be developed. Nanofluids with spherical or rod-shaped metal nanoparticles were investigated. At a volume concentration of 0.5%, the room temperature thermal conductivity of a 2 nm spherical gold nanoparticle-water solution was increased by more than 10% over water alone. Silver nanorods increased the thermal conductivity of ethylene glycol by 53% and water by 26%.

The most significant obstacle to the widespread use of carbon-fiber-based composites by the automotive industry is the high cost of carbon fibers in comparison to other potential structural materials. Carbon fibers are currently produced by thermal pyrolysis of a polyacrylonitrile (PAN) precursor to obtain the desired properties. The most significant cost factors in the process are the high cost of precursors and the high capital equipment and energy costs in conversion to carbon fiber. The Department of Energy is supporting developmental efforts to reduce costs in both precursor production and conversion areas. This paper describes developments in the conversion process. Because of the unsuccessful results of manufacturing carbon fibers through their direct heating with microwave radiation (variable frequency microwave [VFM] and single frequency microwave [SFM] energy), new avenues were explored for this processing.

Approximately 200 to 210 million gallons (or about 2 billion pounds) of antifreeze or engine coolant are produced in North America each year. About 80 percent of this is sold to refill leaking cooling systems. This paper compares the environmental impact of additives in leaking and improperly disposed coolant to other sources of these same chemicals.

The accelerated ash loading of diesel particulate filters (DPFs) with diesel oxidation catalysts (DOCs) mounted upstream by lube-oil derived products was investigated using a single cylinder diesel engine and fuel blended with 5% lube oil. An ash loading protocol is developed which combines soot loading, active soot regeneration, and periodic shutdowns for filter weighing. Active regeneration is accomplished by exhaust injection of diesel fuel, initiated by a backpressure criteria and providing DPF temperatures up to 700°C. In developing this protocol, five DPFs of various combinations of substrates (cordierite, silicon carbide, and mullite) and washcoats (none, low PGM, and high PGM) are used and evaluated. The initial backpressure and rate of backpressure increase with ash varied with each of the DPFs and ash was observed to have an effect on the active soot light-off temperature for the catalyzed DPFs.

A methodology for developing modal vehicle emissions and fuel consumption models is described. These models, in the form of look-up tables for fuel consumption and emissions as functions of vehicle speed and acceleration, are designed for simulations such as the Federal Highway Administration's TRAF-series of models. These traffic models are used to evaluate the impacts of roadway design on emissions and fuel consumption. Vehicles are tested on-road and on a chassis dynamometer to characterize the entire operating range of each vehicle. As a verification exercise the models were used to predict cycle emissions and fuel consumption, and the results were compared to certification-type tests on a different population of vehicles. Results of the verification exercise show that the developed models can generally predict cycle emissions and fuel consumption with error comparable to the variability of repeat dynamometer tests.

The highly successful Galileo mission made a number of startling and remarkable discoveries during its eight-year tour in the harsh Jupiter radiation environment. Two of these revelations were: 1) salty oceans lying under an icy crust of the Galilean moons: Europa, Ganymede and Callisto, and 2) the possible existence or remnants of life, especially on Europa, which has a very tenuous atmosphere of oxygen. Galileo radiation measurement data from the Energetic Particle Detector (EPD) have been used (Garrett et al., 2003) to update the trapped electron environment model, GIRE: Galileo Interim Radiation Environment, in the range of L (L: McIlwain parameter – see ref. 6) = 8–16 Rj (Rj: radius of Jupiter ≈ 71,400 km) with plans to extend the model for both electrons and protons as more data are reduced and analyzed.

Carbon monoxide poisoning from the exhaust of gasoline fueled electric generators on houseboats is a recognized safety hazard. Reducing this hazard by changing the exhaust termination from the waterline location to above the vessel is examined. A CO concentration survey is discussed and the use of smoke to follow the exhaust gas flow patterns is presented with photographs. Conventional waterline exhaust terminations produced CO concentrations above the 1200 PPM that is the Immediately Dangerous to Life and Health value. A vertical stack with a termination above the highest point on the vessel was examined and no CO concentrations of significance were measured on or near the vessel.

The automotive industries throughout the world are continuously optimizing the cost effectiveness for greater value in automotive interiors in order to remain competitive in the market. Moreover, (a) increased importance of renewable resources for raw materials, and (b) recyclability and/or biodegradability of the product at the end of the useful life are demanding a shift from petroleum-based synthetics to agro-based natural fibers in automotive interiors. Natural fiber composites can contribute greatly to the automotive manufacturers' final goal of weight and cost reduction. The approach in this research has been to evaluate ligno-cellulosic fiber based nonwoven composites for automotive and other similar applications.

With increasingly stringent regulations mandating the improvement of vehicle fuel economy, automotive manufacturers face growing pressure to develop and implement technologies that improve overall system efficiency. One such technology is an automatic (auto) stop-start feature. Auto stop-start reduces idle time and reduces fuel use by temporarily shutting the engine off when the vehicle comes to a stop and automatically re-starting it when the brake is released, or the accelerator is pressed. As mandated by the U.S. Congress, the U.S. Environmental Protection Agency (EPA) is required to keep the public informed about fuel saving practices. This is done, in partnership with the U.S. Department of Energy (DOE), through the fueleconomy.gov website. The “Fuel-Saving Technologies” and “Gas Mileage Tips” sections of the website are focused on helping the public make informed purchasing decisions and encouraging fuel-saving driving habits.

Typical calculations of radiation exposures in space approximate the composition of the human body by a single material, typically Aluminum or water. A further approximation is made with regard to body size by using a single anatomical model to represent people of all sizes. A comparison of calculations of organ dose and dose-equivalent is presented. Calculations are first performed approximating body materials by water equivalent thickness', and then using a more accurate representation of materials present in the body. In each case of material representation, a further comparison is presented of calculations performed modeling people of different sizes.

As interest has grown in diesel emissions and diesel engine aftertreatment, so has the importance of analyzing all components of the exhaust. One of the more costly and difficult measurements to make is the collection and analysis of semivolatile organic compounds (SOCs) in the exhaust. These compounds include alkane and alkenes from C12-C24, and the 2-5 ring polycyclic aromatic hydrocarbons (PAH). These compounds can be present in both the particulate (i.e. on the filter) and gaseous phase, and cannot be collected with bag samples. Typically, a sorbent is used downstream of the particulate collection filters to collect these compounds. Sorbent phases include polyurethane foam (PUF), Tenax™, XAD-type resins, and activated carbon. The SOCs are removed from the sorbent either by solvent extraction (PUF and XAD) or thermal desorption (Tenax™ and activated carbon). Each of these methods have advantages and disadvantages.

Currently, the interest in using alternative clean types of fuels has been extensively increased all over the world because of the global approach in reducing engine emissions and creating new sources of fuel for internal combustion engines. The hydrogen-methane blend is one of the alternative fuels which includes the benefits of both of the fuels compared to the traditional petrol/gasoline fuel. This paper addresses a two-zone quasi-dimensional model to investigate the performance of an SI engine which uses a mixture of methane and hydrogen. In this model, gases inside the cylinder are divided into two regions: burned and the unburned. The chemical reactions are supposed to be in equilibrium in each zone, but the extended Zedlovich mechanism is utilized to determine the amount of the NOx available in the exhaust gas. Also, CO concentration is determined by two steps kinematic reactions. The flame front is assumed to be a surface with no thickness in adiabatic flame temperature.