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Mechanisms of NH₃ generation using LNT-like catalysts have been studied in a bench reactor over a wide range of temperatures, flow rates, reformer catalyst types and synthetic exhaust-gas compositions. The experiments showed that the on board production of sufficient quantities of ammonia on board for SCR operation appeared feasible, and the results identified the range of conditions for the efficient generation of ammonia. In addition, the effects of reformer catalysts using the water-gas-shift reaction as an in-situ source of the required hydrogen for the reactions are also illustrated. Computations of the NH₃ and NOx kinetics have also been carried out and are presented. Design and impregnation of the SCR catalyst in proximity to the ammonia source is the next logical step. A heated synthetic-exhaust gas flow bench was used for the experiments under carefully controlled simulated exhaust compositions.

This article is concerned with identification of true stress-strain curve under biaxial tension of thermoplastic polymers. A new type of biaxial tension attachment was embedded first in a universal material test machine, which is able to transform unidirectional loading of the test machine to biaxial loading on the specimen with constant velocity. Cruciform specimen geometry was optimized via FE modeling. Three methods of calculating true stress in biaxial tension tests were compared, based on incompressibility assumption, linear elastic theory and inverse engineering method, respectively. The inverse engineering method is more appropriate for thermoplastic polymers since it considers the practical volume change of the material during biaxial tension deformation. The strategy of data processing was established to obtain biaxial tension true stress-strain curves of different thermoplastic polymers.

In today's highly competitive automotive markets manufacturers must provide high quality products to survive. Manufacturers can achieve higher levels of quality by changing or improving their manufacturing process and/or by product inspection where many strategies with different cost implications are often available. Cost of Quality (CoQ) reconciles the competing objectives of quality maximization and cost minimization and serves as a useful framework for comparing available manufacturing process and inspection alternatives. In this paper, an analytic CoQ framework is discussed and some key findings are demonstrated using a set of basic inspection strategy scenarios. A case of a welded automotive assembly is chosen to explore the CoQ tradeoffs in inspection strategy selection and the value of welding process improvement. In the assembly process, many individual components are welded in series and each weld is inspected for quality.

A set of devices for measurement of human balance orientation and eye movements in weightlessness was developed for neurovestibular experiments on Spacelab. The experiments involve astronaut motion, limb position changes, and moving visual fields, measurements are made of eye movements, muscular activity and orientation perception. This joint US/Canadian research program represent a group of closely related experiments designed to investigate space motion sickness, any associated changes in otolith-mediated responses occurring during weightlessness, and the continuation of changes to postflight conditions. The otoliths are a component of the vestibular apparatus which is located in the middle ear. It is responsible for maintaining the body's balance. Gravitational pull on the otoliths causes them to constantly appraise the nervous system of the position of the head with respect to the direction of gravity.

The fuel energy consumption of subsonic air transportation is examined. The focus is on identification and quantification of fundamental engineering design tradeoffs which drive the design of subsonic tube and wing transport aircraft. The sensitivities of energy efficiency to recent and forecast technology developments are also examined.

The windage tray effect on aeration in the engine sump was assessed by replacing much of the windage tray materials with wire meshes of various blockages. The mesh was to prevent direct impact of the oil drops spinning off the crank shaft onto the sump oil, and simultaneously, to provide sufficient drainage so that there was no significant build up of windage tray oil film that would interact with these droplets. Aeration at the oil pump inlet was measured by X-ray absorption in a production V-6 SI engine motoring at 2000 to 6000 rpm. Within experimental uncertainty, these windage tray changes had no effect on aeration. Thus activities in the sump such as the interaction of the oil drops spun from the crank shaft with the sump oil or with the windage tray, and the agitation of the sump oil by the crank case gas, were not major contributors to aeration at the pump inlet.

We present results which verify the design parameters and suggest performance capabilities/limitations of the Mars Gravity Biosatellite's proposed atmospherics control subassembly. Using a combination of benchtop prototype testing and analytic techniques, we derive control requirements for ammonia. Further, we demonstrate the dehumidification performance of our proposed partial gravity condensing heat exchanger. Ammonia production is of particular concern in rodent habitats. The contaminant is released following chemical degradation of liquid waste products. The rate of production is linked to humidity levels and to the design of habitat modules in terms of bedding substrate, air flow rates, choice of structural materials, and other complex factors. Ammonia buildup can rapidly lead to rodent health concerns and can negatively impact scientific return.

The life of an automotive engine is often limited by the ability of its components to resist wear. Zinc dialkyldithiophosphate (ZDDP) is an engine oil additive that reduces wear in an engine by forming solid antiwear films at points of moving contact. The effects of this additive are fairly well understood, but there is little theory behind the kinetics of antiwear film formation and removal. This lack of dynamic modeling makes it difficult to predict the effects of wear at the design stage for an engine component or a lubricant formulation. The purpose of this discussion is to develop a framework for modeling the formation and evolution of ZDDP antiwear films based on the relevant chemical pathways and physical mechanisms at work.

This paper illustrates a methodology in which complete material-manufacturing process cases for closure panels, reinforcements, and assembly are modeled and compared in order to identify the preferred option for a lightweight closure design. First, process-based cost models are used to predict the cost of lightweighting the closure set of a sample midsized sports utility vehicle (SUV) via material and process substitution. Weight savings are then analyzed using a powertrain simulation to understand the impact of lightweighting on fuel economy. The results are evaluated in the context of production volume and total mass change.

The aim of this study was to explore if fingernail delamination injury following EMU glove use may be caused by compression-induced blood flow occlusion in the finger. During compression tests, finger blood flow decreased more than 60%, however this occurred more rapidly for finger pad compression (4 N) than for fingertips (10 N). A pressure bulb compression test resulted in 50% and 45% decreased blood flow at 100 mmHg and 200 mmHg, respectively. These results indicate that the finger pad pressure required to articulate stiff gloves is more likely to contribute to injury than the fingertip pressure associated with tight fitting gloves.

Battery packs for Hybrids, Plug-in Hybrids, and Electric Vehicles are assembled from a system of modules (sheets) with a tight sheet metal casing around them. Each module consists of an array of individual cells which vary in the composition of electrodes and separator from one manufacturer to another. In this paper a general procedure is outlined on the development of a constitutive and computational model of a cylindrical cell. Particular emphasis is placed on correct prediction of initiation and propagation of a tearing fracture of the steel can. The computational model correctly predicts rupture of the steel can which could release aggressive chemicals, fumes, or spread the ignited fire to the neighboring cells. The initiation site of skin fracture depends on many factors such as the ductility of the casing material, constitutive behavior of the system of electrodes, and type of loading.

A new monitoring system predicts the progression of welding temperature fields during resistance spot welding. The system captures welding voltages and currents to predict contact diameters and simulate temperature fields. The system accurately predicts fusion lines and heat-affected zones. Accuracy holds even for electrode tips used for a few thousand welds of zinc coated steels.

The existing vehicle designs exhibit a high level of coupling. For instance the coupling in the suspension and steering systems manifests itself through the change in wheel alignment parameters (WAP) due to suspension travel. This change in the WAP causes directional instability and tire-wear. The approach of the industry to solve this problem has been twofold. The first approach has been optimization of suspension link lengths to reduce the change in WAP to zero. Since this is not possible with the existing architecture, the solution used is the optimization of the spring stiffness K to get a compromise solution for comfort (which requires significant suspension travel and hence a soft spring) and directional stability (which demands least possible change in wheel alignment parameters and hence a stiff spring).

Computer simulation of extravehicular activity (EVA) is increasingly being used in planning and training for EVA. A space suit model is an important, but often overlooked, component of an EVA simulation. Because of the inherent difficulties in collecting angle and torque data for space suit joints in realistic conditions, little data exists on the torques that a space suit’s wearer must provide in order to move in the space suit. A joint angle and torque database was compiled on the Extravehicular Maneuvering Unit (EMU), with a novel measurement technique that used both human test subjects and an instrumented robot. Using data collected in the experiment, a hysteresis modeling technique was used to predict EMU joint torques from joint angular positions. The hysteresis model was then applied to EVA operations by mapping out the reach and work envelopes for the EMU.

Semi-solid metal (SSM) casting has long been identified as a high-volume process for producing safety-critical and structural automotive castings, but cost and complexity issues have limited its widespread commercial acceptance. Rheocasting, an SSM process that creates semi-solid slurry directly from liquid metal, eliminates the cost disadvantages of the process. However, the majority of rheocasting processes are complex and difficult to operate in the foundry environment. Recent work at MIT has led to the fundamental discovery that application of heat removal and convection as a molten alloy cools through the liquidus creates a non-dendritic, semi-solid slurry. A new process based on this understanding, S.S.R.™ (Semi-Solid Rheocasting), simplifies the rheocasting process by controlling heat removal and convection of an alloy during cooling using an external device. Solution heat treatable castings have been produced in a horizontal die casting machine with the S.S.R.™ process.

The piston skirt is an important contributor of friction in the piston assembly. This paper discusses friction contributions from various aspects of the piston skirt. A brief study of piston skirt patterns is presented, with little gains being made by patterning the piston skirt coating. Next the roughness of the piston skirt coating is analyzed, and results show that reducing piston skirt roughness can have positive effects on friction reduction. Finally, an introductory study into the profile of the piston skirt is presented, with the outcome being that friction reduction is possible by optimizing the skirt profile.

This paper presents the results of a study of how people interacted with a production voice-command based interface while driving on public roadways. Tasks included phone contact calling, full address destination entry, and point-of-interest (POI) selection. Baseline driving and driving while engaging in multiple-levels of an auditory-vocal cognitive reference task and manual radio tuning were used as comparison points. Measures included self-reported workload, task performance, physiological arousal, glance behavior, and vehicle control for an analysis sample of 48 participants (gender balanced across ages 21-68). Task analysis and glance measures confirm earlier findings that voice-command interfaces do not always allow the driver to keep their hands on the wheel and eyes on the road, as some assume.

Advanced driver assistance systems (ADAS) are an increasingly common feature of modern vehicles. The influence of such systems on driver behavior, particularly in regards to the effects of intermittent warning systems, is sparsely studied to date. This paper examines dynamic changes in physiological and operational behavior during lane departure warnings (LDW) in two commercial automotive systems utilizing on-road data. Alerts from the systems, one using auditory and the other haptic LDWs, were monitored during highway driving conditions. LDW events were monitored during periods of single-task driving and dual-task driving. Dual-task periods consisted of the driver interacting with the vehicle’s factory infotainment system or a smartphone to perform secondary visual-manual (e.g., radio tuning, contact dialing, etc.) or auditory-vocal (e.g. destination address entry, contact dialing, etc.) tasks.

The combustion process after auto-ignition is investigated. Depending on the non-uniformity of the end gas, auto-ignition could initiate a flame, produce pressure waves that excite the engine structure (acoustic knock), or result in detonation (normal or developing). For the “acoustic knock” mode, a knock intensity (KI) is defined as the pressure oscillation amplitude. The KI values over different cycles under a fixed operating condition are observed to have a log-normal distribution. When the operating condition is changed (over different values of λ, EGR, and spark timing), the mean (μ) of log (KI/GIMEP) decreases linearly with the correlation-based ignition delay calculated using the knock-point end gas condition of the mean cycle. The standard deviation σ of log(KI/GIMEP) is approximately a constant, at 0.63. The values of μ and σ thus allow a statistical description of knock from the deterministic calculation of the ignition delay using the mean cycle properties

The ability to make accurate decisions concerning early body-in-white architectures is critical to an automaker since these decisions often have long term cost and weight impacts. We address this need with a methodology which can be used to assist in body architecture decisions using process-based technical cost modeling (TCM) as a filter to evaluate alternate designs. Despite the data limitations of early design concepts, TCM can be used to identify key trends for cost-effectiveness between design variants. A compact body-in-white architecture will be used as a case study to illustrate this technique. The baseline steel structure will be compared to several alternate aluminum intensive structures in the context of production volume.