Refine Your Search

Topic

Author

Affiliation

Search Results

Technical Paper

Extinction of Methanol and Ethanol Flames in Premixed Flows

2007-01-23
2007-01-0057
Alcohols like methanol (CH3OH) and ethanol (C2H5OH) are well known alternative fuels. Ethanol, which replaced MTBE in California, is added to regular gasoline up to 5% without any modifications required to a normal gasoline engine. Recently E85, an ethanol-gasoline mixture of 85% ethanol and 15% gasoline derived from crude oil, got attention as an alternative fuel due to high gas prices and environmental acceptance. Therefore, it is important to understand the basics of alcohol combustion. Experimental and numerical studies are conducted on extinction of methanol and ethanol flames in premixed laminar flows. The studies are performed in a counter-flow configuration. The burner used in the experiments is made up of two opposing ducts. Two configurations are considered. In one configuration, a premixed reactant stream made up of vaporized fuel, air, and nitrogen is introduced from one duct and nitrogen from the other.
Technical Paper

Approach Combined Numerical and Experimental Analysis for Motorcycle Engine Radiation Noise

2006-11-13
2006-32-0086
In recent motorcycles, radiation noise from engine surface dominates high percentage since enough measures have been taken for other noise sources such as intake, exhaust and drive train noise. Since most motorcycle engines consist with transmissions, the radiation noise is caused not only from combustion pressure but also from the gear meshing. Therefore radiation noise accounts for higher frequency than the other noise sources like intake and exhaust. At present, in order to reduce the radiation noise, we have to take countermeasures on actual engines since CAE is difficult to apply because of the characteristic of many high frequency components. In this study, technical build-up was made to enable the estimation of the engine radiation noise. Build-up was made of the modeling know-how of FE models capable of analyzing high frequency. We determined excitation force to the bearing housings in consideration of combustion force and gear meshing force based on the experimental data.
Technical Paper

Innovative Composite Structure Design for Blast Protection

2007-04-16
2007-01-0483
An advanced design methodology is developed for innovative composite structure concepts which can be used in the Army's future ground vehicle systems to protect vehicle and occupants against various explosives. The multi-level and multi-scenario blast simulation and design system integrates three major technologies: a newly developed landmine-soil-composite interaction model; an advanced design methodology, called Function-Oriented Material Design (FOMD); and a novel patent-pending composite material concept, called BTR (Biomimetic Tendon-Reinforced) material. Example results include numerical simulation of a BTR composite under a blast event. The developed blast simulation and design system will enable the prediction, design, and prototyping of blast-protective composite structures for a wide range of damage scenarios in various blast events.
Technical Paper

Robustness of a LNT-SCR System to Aging Protocol

2007-04-16
2007-01-0469
Experiments were conducted to determine the effect of accelerated aging on LNT-SCR system performance. The systems were aged and evaluated on an engine dynamometer using a DW12 2.2L I4 Diesel. The aging consisted of three modes, including sulfur exposure, desulfation (deSOx), and DPF regeneration conditions. Two systems were aged using different desulfation protocols and then evaluated over steady-state cycling conditions. The sulfur release characteristics were measured. Overall system gross NOx conversion was robust to the aging protocol; however, there were significant differences in the individual component performance depending on the nature of the aging conditions. LNT NOx conversion was significantly lower for the case where maximum temperatures reached only 730°C, as opposed to the more severe aging where temperatures reached 800°C.
Technical Paper

Influence of Interfacial Interaction on the Foamability of Wood Fiber/HDPE Composites

2007-04-16
2007-01-0577
This research presents a fundamental study of the interaction between chemically modified wood fibers and high density polyethylene (HDPE) to develop wood fiber/HDPE composites with satisfactory performance. This paper investigates the effects of the interfacial properties of HDPE and wood fibers on the rheological properties and foaming behavior of the composites. The surface characteristics of wood fiber were modified by treating the fiber with trialkoxy silane. The effectiveness of chemical surface modifications of wood fiber was characterized using FT-IR. The effect of the interfacial interaction on the foaming behavior was studied via extrusion foaming with a physical blowing agent. The rheological property of the composites with a different interfacial structure were also evaluated by using dynamic oscillatory rheometer.
Technical Paper

Development of a Database of Full-Scale Calorimeter Tests of Motor Vehicles

2007-04-16
2007-01-1233
This paper describes the development of a database of full-scale motor vehicle fire test results. The data were obtained from a careful review of 20 publications1-20 comprised of: 3 journal articles, 2 conference papers, and 15 reports. To be included in the database, tests had to involve heat release rate measurements. A total of 33 tests in 12 studies were found to meet this requirement. The database consists of four interrelated tables that contain primarily scalar data. The main table includes links to available time-dependent data, i.e., heat release rate, mass loss, interior temperature, interior heat flux and interior CO concentration vs. time. The data may be useful in fire engineering, e.g., fire design of parking garages, fire hazard assessment of automotive materials in post-collision fires, etc. Use of the database is illustrated with an example.
Technical Paper

Small-Scale Flammability Testing of Polyester and Polyamide Formulations Used in Electrical Connector Applications

2007-04-16
2007-01-1234
This paper addresses small-scale flammability testing of materials used in electrical connector applications. It discusses existing technology that is available to potentially improve fire safety in response to challenges posed by changing materials and technology. The focus of this paper is the flammability of polyester and polyamide. Several different small-scale flammability tests were used to evaluate these materials and set a basis for future small-scale and full-scale evaluations.
Technical Paper

Fuel Tank and Charcoal Canister Fire Hazards during EVAP System Leak Testing

2007-04-16
2007-01-1235
The combination of on-board diagnostics and evaporative emission control (EVAP) systems has led to a growing need to identify and repair leaks in automotive EVAP systems. The normal leakfinding method involves purging the system with a smoke fluid, usually air or nitrogen containing an oil aerosol and then looking for a visual indication of the leak. The purge flow used to distribute smoke through the system displaces substantial amounts of fuel vapor from the tank vapor space and can also raise the oxygen level inside the fuel system. If any ignition source is present, the formation of flammable mixtures both inside and outside the vehicle systems can lead to a flash fire hazard associated with leak finding procedures. Currently available fire statistics (such as NFPA) are not sufficiently detailed to attribute service shop fires to specific testing procedures.
Technical Paper

Under Hood Temperature Measurements

2007-04-16
2007-01-1393
In addition to gasoline, other automotive fluids such as engine oil, transmission oil, brake fluid, coolant and power steering fluid are combustible and if exposed to an ignition source can ignite and result in a vehicle fire. Ignition sources may include sparks, flames, or hot engine or exhaust components. Under normal vehicle operating conditions these fluids are well contained and do not pose a fire threat. However, the risk of fire increases if the fluids are spilled or released in a collision. In-vehicle temperature measurements were conducted to identify operating engine and exhaust temperatures under various driving conditions ranging in speed from 48 to 112 km/h (30 to 70 mph).
Technical Paper

Wavelet-based Non-parametric Estimation of Injury Risk Functions

2007-04-16
2007-01-1156
An injury risk function defines the probability of an injury as a function of certain measurable or known predictors. In this paper, wavelet analysis is employed for the non-parametric estimation of injury risk functions. After a brief introduction of the wavelet theory, the representation of density function by wavelet series is given. A procedure for the estimation of density function is described. The risk function estimation for right-censored data is investigated by introducing hazard rate function and its wavelet estimator. The use of the developed method is illustrated in a case study, where two sets of data are used: simulation data with known distribution and censoring information, and thoracic impact testing data, which are assumed to be right- censored. Comparisons are made between the wavelet-based approach and the empirical Kaplan-Meier non-parametric method.
Technical Paper

The Door Mounted Inflatable Curtain

2006-04-03
2006-01-1437
It has been shown that Inflatable Curtains have the potential to reduce head injuries in side impacts and the system has accordingly been introduced on a growing number of car models. There is also a potential benefit in rollover situations. This paper only consider performance in situations with belted occupants. To date, it has not been possible to implement an Inflatable Curtain in convertible vehicles because they lack a roof. The challenge of the Door Mounted Inflatable Curtain (DMIC) has been to overcome the lack of support and fixation possibilities offered by a roof. This paper includes a description of the DMIC and how it was integrated into the vehicle structure. The paper will also show how to create the space and support needed to utilize the internal stiffness and make it possible to fill the bag in time. The impact attenuation and ejection protection functions of the DMIC will be demonstrated.
Technical Paper

Development and Testing of a Microwave Powered Solid Waste Stabilization and Water Recovery System

2006-07-17
2006-01-2182
A Microwave Powered Solid Waste Stabilization and Water Recovery Prototype system has been developed for the treatment of solid waste materials generated during extended manned space missions. The system recovers water initially contained within wastes and stabilizes the residue with respect to microbial growth. Dry waste may then be safely stored or passed on to the next waste treatment process. Using microwave power, water present in the solid waste is selectively and rapidly heated. Liquid phase water flashes to steam and superheats. Hot water and steam formed in the interior of waste particles create an environment that is lethal to bacteria, yeasts, molds, and viruses. Steam contacts exposed surfaces and provides an effective thermal kill of microbes, in a manner similar to that of an autoclave. Volatilized water vapor is recovered by condensation.
Technical Paper

Advanced Miniature IR Spectral Processor for the Infrared Spectral Monitoring of Spacecraft Vital Life-Support Systems and Remote Astronaut Health Diagnostics

2006-07-17
2006-01-2178
Infrared (IR) spectroscopy probes the characteristic vibrational and rotational modes of chemical bonds in molecules to provide direct information about both the chemical composition and the bonding configuration of a sample. The significant advantage of the IR spectral technique is that it can be used with minimal consumables to simultaneously detect a large variety of different chemical and biochemical species with high chemical specificity. Currently, various VIS/NIR grating spectrometers are employed to cover the spectral range between 0.3 and about 2.2 (μm. Bulk-optic Fourier Transform (FT)-IR spectrometers employing variations of the Michelson interferometer are generally used to provide spectral measurements above 2.5 (μm. The FT-IR systems tend to be mechanically complex, bulky (>15 kg), and require considerable processing, maintenance and recalibration. For space-based systems, the important drivers are reliability, power consumption, mass and simplicity of operation.
Technical Paper

Numerical Study of the Generation of Linear Energy Transfer Spectra for Space Radiation Applications

2006-07-17
2006-01-2144
In analyzing charged particle spectra in space due to galactic cosmic rays (GCR) and solar particle events (SPE), the conversion of particle energy spectra into linear energy transfer (LET) distributions is a convenient guide in assessing biologically significant components of these spectra. The mapping of LET to energy is triple valued and can be defined only on open energy subintervals where the derivative of LET with respect to energy is not zero. Presented here is a well-defined numerical procedure which allows for the generation of LET spectra on the open energy subintervals that are integrable in spite of their singular nature. The efficiency and accuracy of the numerical procedures is demonstrated by providing examples of computed differential and integral LET spectra and their equilibrium components for historically large SPEs and 1977 solar minimum GCR environments. Due to the biological significance of tissue, all simulations are done with tissue as the target material.
Technical Paper

LET Spectra of High Energy Proton Beam on A-150: Model Predictions for the CRaTER Detector

2006-07-17
2006-01-2145
Doses to human crews in interplanetary space from energetic Solar Particle Events (SPE) are of a special concern for future lunar missions. The Lunar Reconnaissance Orbiter (LRO) mission, scheduled to launch by the end of 2008 into Lunar orbit, will conduct several exploratory objectives, one of which is characterizing the lunar radiation environment and its biological impacts on humans. Research is currently being conducted for the purpose of developing a sensor system to be flown on the LRO called the Cosmic Ray Telescope for the Effects of Radiation (CRaTER) to measure the Linear Energy Transfer (LET) Spectra of SPE, providing a link between the Moon’s radiation environment and its biological impact on humans.
Technical Paper

MicroDosimeter iNstrument (MIDN) on MidSTAR-I

2006-07-17
2006-01-2146
The goal of this project is to develop and test in space a solid-state microdosimeter to directly assess astronaut risk to an unknown mixed radiation field. The instrument is rugged, has low power (< 1.25W), has low mass, and utilizes low voltages (± 5V). A microdosimeter can determine in real time dose equivalent in sieverts which is the regulatory quantity used to evaluate risk and limits of radiation exposure. The lineal energy spectrum that it measures can be multiplied by lineal-energy-dependent regulatory quality factors to determine dose equivalent. An early version of the instrument (MIDN on MidSTAR-I) has been designed and built for inclusion in the MidSTAR-1 USNA student built satellite to be launched in late fall 2006. The instrument is now undergoing test and minor modifications.
Technical Paper

Steps Toward Developing a Multi-layer Green’s Function Code for Ion Beam Transport

2006-07-17
2006-01-2148
Recently, a new Green’s function code (GRNTRN) for simulation of HZE ion beams in the laboratory setting has been developed. Once fully developed and experimentally verified, GRNTRN will be a great asset in assessing radiation exposures in both the laboratory and space settings. The computational model consists of combinations of physical perturbation expansions based on the scales of atomic interaction, multiple elastic scattering, and nuclear reactive processes with use of Neumann-series expansions with non-perturbative corrections. The code contains energy loss with straggling, nuclear attenuation, nuclear fragmentation with energy dispersion and down shifts. Previous reports show that the new code accurately models the transport of ion beams through a single slab of material. Current research efforts are focused on enabling the code to handle multiple layers of material and the present paper reports on progress made towards that end.
Technical Paper

Space Radiation Exposure Mitigation: Study of Select Materials

2006-07-17
2006-01-2103
The development of “next generation” human-rated space vehicles, surface habitats and rovers, and spacesuits will require the integration of low-cost, lightweight materials that also include excellent mechanical, structural, and thermal properties. In addition, it is highly desirable that these materials exhibit excellent space radiation exposure mitigation properties for protection of both the crew and onboard sensitive electronics systems. In this paper, we present trapped electron and proton space radiation exposure computational results for a variety of materials and shielding thicknesses for several earth orbit scenarios that include 1) low earth orbit (LEO), 2) medium earth orbit (MEO), and 3) geostationary orbit (GEO). We also present space radiation exposure (galactic cosmic radiation and solar particle event) results as a function of selected materials and thicknesses.
Technical Paper

Risk Assessment and Shielding Design for Long-Term Exposure to Ionizing Space Radiation

2006-07-17
2006-01-2108
NASA is now focused on the agency's vision for space exploration encompassing a broad range of human and robotic missions including missions to Moon, Mars and beyond. As a result, there is a focus on long duration space missions. NASA is committed to the safety of the missions and the crew, and there is an overwhelming emphasis on the reliability issues for space missions and the habitat. The cost effective design of the spacecraft demands a very stringent requirement on the optimization process. Exposure from the hazards of severe space radiation in deep space and/or long duration missions is ‘the show stopper.’ Thus, protection from the hazards of severe space radiation is of paramount importance to the new vision. It is envisioned to have long duration human presence on the Moon for deep space exploration. As NASA is looking forward to exploration in deep space, there is a need to go beyond current technology to the technology of the future.
Technical Paper

Passive Radiation Shielding Investigations in Low Earth Orbit and in an Accelerator

2006-07-17
2006-01-2105
Crews of future exploration missions will be exposed for long time to a unique powerful mix of cosmic radiation. Starting from REMSIM study for ESA, we are focusing on short and long term shielding experiments aboard ISS (ESCHILO, ALTCRISS, SOFOCLE) by comparing the materials used in inflatable structures with the typical rigid materials used in current spacecraft, and optimizing and validating the radiation shielding solutions in LEO. To assess shielding strategies, tests in flight are always supported by calculations and laboratory experiments. The paper reports descriptions and available results of the above experiments.
X