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A bioregenerative diet is characterized by a high proportion of foods produced on site. The production and processing of foods into either ingredients or recipes entails certain labor requirements. Ideally these labor requirements should be estimated with a high degree of accuracy. Crew time is at premium and any amount of time spent on food preparation and processing is time not spent in conducting research and any other activities devised to improve the quality of life of the astronauts. Moreover, a wide variety of tasks are involved in the food preparation of a bioregenerative diet and the labor times of these tasks do not scale or increase in uniform fashion. Predicting food preparation labor requirements for varying crew sizes will require task specific models and data. Videotape analysis is a work measurement tool used in the manufacturing industry.

Activated carbons have a unique capability of strongly absorbing a great variety of species, ranging from SO2 and NOx, to trace organics, mercury, and other heavy metals. Activated carbons can also be used for gas storage and gas separations, including systems of practical interest to NASA (e.g., CO2/N2/O2), and even for the purification of liquids. No single activated carbon is suitable for all applications, but appreciable control over sorbent properties can be exercised in the process of carbon preparation. Since activated carbons can be produced from a wide range of organic materials, including waste streams, the preparation of activated carbons on board spacecraft should involve a limited amount of additional resources, help manage on-board waste, and reduce the weight of materials to be launched from earth. The feasibility of producing waste-derived activated carbons suitable for SO2 and NO control was the subject of the current study.

This research focuses on the injury potential of children seated in forward facing child restraint seats during frontal vehicle crashes. Experimental sled tests were completed in accordance to the Federal Motor Vehicle Safety Standard 213 using a Hybrid III three-year-old dummy in a five point child restraint system. A full vehicle crash test was completed in accordance to the Canadian Motor Vehicle Safety Standard 208 with the addition of a three-year-old Hybrid III crash test dummy, seated behind the passenger seat, restrained in the identical five-point child safety seat. Different child restraint finite element models were developed incorporating a subset of the apparatus used in the two experimental tests and simulated using LS-DYNA.

Laser excitation wavelengths for two-line planar laser-induced fluorescence (PLIF) of 3-pentanone have been optimized for simultaneous imaging of temperature and composition under engine-relevant conditions. Validation of the diagnostic was performed in a motored optical IC engine seeded homogeneously with 3-pentanone. PLIF measurements of the uniform mixture during the compression stroke were used to measure the average temperature and to access the random uncertainty in the measurements. To determine the accuracy of the temperature measurements, experimental average temperatures were compared to values computed assuming isentropic compression and to the output of a tuned 1-D engine simulation. The comparison indicated that the absolute accuracy of the temperature measurements is better than ±5%. Probability density functions (PDFs) calculated from the single-shot images were used to estimate the precision of the measurements.

“Truck Ride” in this study refers to some vehicle ride parameters involved in tractor-trailer combinations. For the study, a mathematical model of a tractor-trailer vehicle as a vibrating system was developed. Principles of vibration theory were applied to the model while a digital computer was employed to investigate the complex system. To parallel the analytical investigation of the tractor-trailer vehicle, vehicle studies were conducted using a magnetic tape recorder and associated instrumentation installed in the tractor. Parameters studied included coupler position on the tractor, laden weight of trailer, spring rates of the different axles of the combination, damping capacity associated with each spring rate, vehicle speed, and “tar strip” spacing of the highway and cab mountings. The mathematical results were used as a basis for empirical study. A comparison of calculated and empirical data are reported.

This paper describes the addition of tandem-drive axles and tractor suspension dynamics to a digital computer model of a tractor-semitrailer truck. The extended model provides 22 degrees of freedom for the vehicle. Two degrees of freedom are included for the motion of each tractor axle; vertical tire flexibility, tandem-axle suspension jacking, and tandem-axle roll steer are also included in the extended model. The features of the previous vehicle model (based on the work of Mikulcik) are retained in the extended model. These features include nonlinear equations for translation, yaw, pitch, and roll of both the tractor and the semitrailer (except as these motions are constrained by the fifth wheel), wheel rotation dynamics, and antiskid brake control. The model also includes a simulated “driver” which specifies the steering angle and the air pressure applied to the brakes.

Standard CFD methods require a mesh that fits the boundaries of the computational domain. For a complex geometry the generation of such a grid is time-consuming and often requires modifications to the model geometry. This paper evaluates the Immersed Boundary (IB) approach which does not require a boundary-conforming mesh and thus would speed up the process of the grid generation. In the IB approach the CAD surfaces (in Stereo Lithography -STL- format) are used directly and this eliminates the surface meshing phase and also mitigates the process of the CAD cleanup. A volume mesh, consisting of regular, locally refined, hexahedrals is generated in the computational domain, including inside the body. The cells are then classified as fluid, solid and interface cells using a simple ray-tracing scheme. Interface cells, correspond to regions that are partially fluid and are intersected by the boundary surfaces.

Little of the long-recognized potential of variable valve timing (VVT) has yet been realized, mainly because of the many limitations that characterize virtually all the mechanisms that have been proposed for VVT application. These limitations include high cost and complexity, mechanism energy losses, limited range of variability, and high valve impact velocities. We have developed a two-degree-of-freedom mechanism, actuated by two cams operating in series, that appears well-suited for VVT applications. This new mechanism avoids the serious limitations that characterize virtually all other VVT mechanisms. It is relatively simple and it can be implemented using only standard-type major components. It can provide a wide range of valve open duration without excessive mechanical losses or high impact velocities. We examine this mechanism in depth. Experimental verification of the operation of this mechanism confirms the mechanical adequacy of the concept at practical engine speeds.

Lithium-ion batteries (LIBs) repurposed from retired electric vehicles (EVs) for grid-scale energy storage systems (ESSs) have the potential to contribute to a sustainable, low-carbon-emissions energy future. The economic and technological value of these “second-life” LIB ESSs must be evaluated based on their operation on the electric grid, which determines their aging trajectories. The battery research community needs experimental data to understand the operation of these batteries using laboratory experiments, yet there is a lack of work on experimental evaluation of second-life batteries. Previous studies in the literature use overly-simplistic duty cycling in order to age second-life batteries, which may not produce aging trajectories that are representative of grid-scale ESS operation. This mismatch may lead to inaccurate valuation of retired EV LIBs as a grid resource.

This paper is concerned with a series of three important problems on reliability where complete solutions are still unavailable. These problems have all been researched and approximate solutions are outlined. The three areas of interest are 1. The government requirement of assurance of high reliability of complex items where the cost of sampling is extremely high. 2. Confidence intervals for a system in series where component data are available, and 3. Estimation of the parameters of the Weibull distribution when sampling terminates after the rth failure is observed in a sample of size n.

This paper presents a new measurement technique for in-cylinder gas temperature and residual gas concentration during the compression stroke of an internal combustion (IC) engine. This technique is based on the infrared absorption of water vapor by a wavelength modulated laser. Wavelength modulation spectroscopy with second harmonic detection (WMS-2f) was adopted to enable the short-path measurements over a wide range of temperatures and pressures corresponding to the late compression stroke in a typical automotive engine. The WMS-2f signal is detected through a bandpass filter at a width of 7.5 kHz, enabling crank angle-resolved measurements. The temperature is determined from the ratio of optical absorption for two overtone transitions of water vapor in the intake gas mixture, and the H2O concentration is determined from this inferred temperature and the absorption for one of the transitions.

A computer model of a tractor-semitrailer is developed which extends that given by Mikulcik in SAE 710045 (Ref. 10 of paper). The extended model allows translation, yaw, roll, and pitch of both tractor and semitrailer. Lateral and fore-and-aft weight transfer is displayed. Wheel dynamics are included, and effects of wheel slip, slip angle, vehicle speed, and tire load are used in the calculation of the tire forces. The vehicle is maneuvered by a simulated driver who specifies the front-wheel steer angle and the brake torques. The ability of the model to accurately describe a real vehicle is studied by using the model to simulate a full-scale experimental test. The model is also used to study two types of proportional braking for a tractor-semitrailer executing a large-radius turn on a wet asphalt track.

The paper presents a method for shorter evaluation of the fatigue damage done by an irregular sequence of loads. The method looks first for the largest overall range from highest peak to lowest valley, then for the next largest overall range that interrupts the first range, and so on, down until a suitable fraction (for example, 10%) of all reversals have been used. These few reversals form a short history, which will do substantially the same damage as the total history. The process is applied to three long histories selected by the SAE Fatigue Design and Evaluation Committee. The sensitivity of calculated damage to the omission of smaller ranges is computed for plain and for notched specimens. The error is compared with differences produced by different current rules for evaluating damage, by different cycle counting methods, and by smooth specimen simulation of notched parts.

Gasoline particulate filters (GPFs) are devices used to filter soot emitted by gasoline direct injection (GDI) engines. A numerical model for a ceria-coated GPF presented in a previous paper by H. Arunachalam et al. in 2017 was developed to predict internal temperature and soot amount combusted during regeneration events. Being that both the internal temperature and the accumulated soot cannot be directly measured during real-time operation and owing to their critical importance for GPF health monitoring as well as regeneration scheduling, the above model turns out to be a valuable tool for OBD applications. In this paper, we first conduct a stochastic analysis to understand the relation between the model parameters and the initial value of the ceria (IV) oxide volume fraction, as a deterministic value for such a state is not known.

In this work, we conduct a sensitivity analysis of the mean-value internal combustion engine exergy-based model, recently developed by the authors, with respect to different driving cycles, ambient temperatures, and exhaust gas recirculation rates. Such an analysis allows to assess how driving conditions and environment affect the exergetic behavior of the engine, providing insights on the system’s inefficiency. Specifically, the work is carried out for a military series hybrid electric vehicle.

For high-load applications, natural gas represents a clean burning, readily available, and relatively inexpensive alternative to number 2 Diesel fuel. However, the fuel’s poor ignitability has previously limited implementation to spark ignited and dual-fueled engines. These approaches suffer from reduced peak load and high engine-out particulate emissions, respectively, requiring lean operation and expensive aftertreatment to meet regulatory standards. A high-temperature combustion strategy can overcome the difficult ignitibility, allowing for true Diesel-style combustion of pure methane-the least ignitable and least sooting component of natural gas. In order to achieve this result, a compression system was designed to supply fuel at pressures suitably high to achieve good mixing and short injection durations, and a solenoid-actuated Diesel fuel injector was modified to function at these pressures with a gaseous fuel.

A low-pressure direct injection fuel system for spark ignition direct injection engines has been developed, in which a high-turbulence nozzle technology was employed to achieve fine fuel droplet size at a low injection pressure around 2 MPa. It is particularly important to study spray characteristics in the near-nozzle region due to the immediate liquid breakup at the nozzle exit. By using an ultrafast x-ray area detector and intense synchrotron x-ray beams, the interior structure and dynamics of the direct injection gasoline sprays from a multi-orifice turbulence-assisted nozzle were elucidated for the first time in a highly quantitative manner with μs-temporal resolution. Revealed by a newly developed, ultrafast computed x-microtomography technique, many detailed features associated with the transient liquid flows are readily observable in the reconstructed spray.

In order to support effective recycling of resources in a bioregenerative life support system (BLSS), the processing of inedible agricultural wastes into edible food products must be included. The process of converting agricultural waste into usable food resources is called secondary food production. Secondary food production offers a way to reclaim part of the energy and nutrients already sunk in inedible biomass, thus increasing the efficiency of the BLSS and crop harvest index. However, multi-step processes and lower yields and acceptability have made some secondary food production processes in the past problematic and costly. This paper presents preliminary process descriptions for secondary food products which are likely to be cost effective and well accepted: sugar syrup prepared from biomass hydrolysate, single cell oil produced from biomass hydrolysate, and Pleurotus mushroom fruit bodies grown on recalcitrant biomass and unused substrate.

This paper presents predictions of fatigue crack initiation life for three distinctly different, irregular load histories, each applied to keyhole-notched compact tension specimens at several maximum load levels and using two different structural steels. Work leading to this paper was done in conjunction with the cooperative research program of the SAE Fatigue Design and Evaluation Committee. Three computerized prediction methods (Landgraf, Wetzel, and a Nominal Stress Range approach) are used. All predictions are based on load histories condensed to 10% of their original number of reversals by the “Racetrack Method.” This method, which is described in detail, selects the most damaging overall ranges in an irregular load history while preserving the sequence of the original loading. Predictions are compared with test data for the two dozen combinations of loading type and level and steel used. Comments are made on the relative merits of the different prediction methods.

The new concept of “human-machine shared control” provides an amazing thinking to enhance driving safety, which has been attracted a great deal of research effort in recent years. However, little attention has been paid to the nonlinearity of the shared control system brought by the tire, which significantly influences the control performance under extreme driving conditions. This paper presents a novel shared steering torque control scheme to model the human-machine steering torque interaction near the vehicle’s handling limit, where both driver and driver assistance system (DAS) are exerting steering torque to maneuver the vehicle. A six-order driver-vehicle dynamic system is presented to elaborate the relationship between steering torque input and vehicle lateral motion response. Particularly, we use a piecewise affine (PWA) method to approximate the tire nonlinearity.