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Selecting the proper work group to resolve engineering issues is an unconventional process used by some Saturn engineering teams that give them a definite competitive edge. This process and training will not only improve performance but generate greater awareness between team members of various issues being worked by the group. Conventional Linear work groups are two dimensional and each cell (engineering resource) has a specific function. The cells will only perform the functions assigned by management. A Cluster work group is three dimensional and each cell shares the responsibility of the other. They are able to assume the rolls of each other through team issue awareness and “team imposed” training. This multi-functional team is not only able to close issues faster when they arise, but also in many cases, to stop a potential issue before it even hits the manufacturing facility.

A joint project was undertaken with an auto industry group, the Environmental Research Consortium (ERC), J-TEC Associates, Inc., and the Oak Ridge National Laboratory (ORNL) to develop an economical, real-time exhaust gas flow measurement system. A commercially available flowmeter did not exist for vehicle applications, even after 40 years of various attempts. The flowmeter that was developed, using vortex-shedding measurement principles, has wide rangeability, high accuracy, and environmental compatibility. While near-term benefits of the technology include the capability to certify a vehicle's ability to meet new environmental regulations, the flowmeter can also be used to assist in the development of new engines and enhanced engine performance.

Implementing Lean Manufacturing systems has become a driving force for achieving low cost production in today's manufacturing environments. The goals of lean manufacturing systems include reducing Work In Process (WIP), reducing non-value added production time, and reducing total operating costs to achieve a more agile and flexible production system. However, a low operating cost system that is not capable of meeting customer demand can become very expensive due to lost sales and market share. Simulation modeling can be used to optimize the process while applying lean manufacturing concepts and achieving throughput requirements. Simulation modeling can determine where a process can afford to become lean while monitoring system responses to ensure system requirements are achieved.

The focus of this effort is to illustrate to the decision-makers in the automobile industry the value of Flexible Simulation Modeling (FSM) as a mechanism to implement pervasive simulation modeling. Pervasive simulation implies the use of simulation throughout the organization from design of the product to actual production of the product. This concept is a key to automotive manufacturers reducing their cost of reiterative modification, and destructive testing. Flexible Simulation Models is a term that describes simulation models that is coupled with other software to allow the user to redesign the production process to modify the characteristics of the current production process in a user friendly manner to encourage the use of simulation. FSM has two primary advantages over current static simulation modeling. First, the user is no longer dependent on simulation expertise or a programmer to reprogram the model when changes to the model want to be investigated.

The main objective of this study is to simulate the design and operational policies of the assembly shop of an automotive plant for planning purposes and to find possible improvements. The simulation study was used to answer the following questions: How does the sequence affect the daily throughput? What conveyor speeds are required to achieve a target output? How do the buffers between lines affect product flow and impact the line stoppage? What are the bottlenecks to the assembly lines in a given scenario? A simulation model was developed in accordance with the objective of this study. The model incorporates detailed workstation logic to accurately model downtime results through the use of a pull cord system. It is written with SIMAN. The discrete event feature of SIMAN does not adequately model the conveyor systems of the assembly shop. As a result, a few subroutines were added to the SIMAN modeling structures to mimic the operations of the assembly shop.

It is often argued that environmental regulations stifle economic development by diverting resources from wealth building to environmental protection. It is not unusual for those responsible for attracting business and industry to a state or city to oppose strengthening environmental regulations for fear that new or more stringent regulations will discourage industry from their locale due to the increased cost of doing business in that area. To counter this belief, the purpose of this paper is to detail the environmental features incorporated into building the Saturn facility. Additionally, the proven and expected benefits of going beyond compliance with environmental regulations will be examined.

The US Environmental Protection Agency has initiated the development of several new air pollution emission standards to limit the emissions of hazardous air pollutants (HAP) from industrial surface coating operations. These rules will require the application of Maximum Achievable Control Technology (MACT) to reduce HAP emissions from new and existing surface coating operations. The Clean Air Act Amendments of 1990 mandated the development of these new rules and EPA intends to promulgate the surface coating MACT rules by November of 2000.

A substantial lead time affects the flexibility of the vehicle manufacturer to respond to changes in customer color preferences. Failure to provide colors that satisfy customer color expectations creates obvious disadvantages in the marketplace. Lead time is generally attributed to pre-production requirements including performance validation testing and other physical properties testing. Additionally, the paint color selection and release for the production process, particularly at the conception stage, relies heavily on subjective judgement and interpretation of the customer's likes and dislikes. A unique method and apparatus have proven useful to meeting the challenges of changing marketing conditions. The technique combines visualizing, developing, engineering, and evaluating a coating so that color becomes an output of a technical process rather than a design process. It allows the business to part from the traditional method of encouraging single color design and development.

A hallmark of environmental leadership is the ability to systematically integrate environmental planning and performance into the various aspects of business. This paper will describe Saturn Corporation's experience and techniques associated with involving suppliers in environmental stewardship. Specifically, the paper will detail several Saturn-Supplier program attributes minimizing manufacturing-related environmental impacts, such as Saturn's: Supplier relations philosophy Supplier selection process Systems development, including material planning, cost allocation, purchasing and training, Structure and Administration of supplier programs Lastly, the paper will generally describe additional existing and near-term opportunities in supplier interactions, which may add further value to automotive products and production.

Due to the part size and technological limitations of the available assembly equipment, traditional wing manufacturing has consisted of a three stage process. Parts are first manually tacked together in an assembly jig, They are then removed from the jig, rotated horizontally and craned into an automated fastening machine. Finally they are removed from the fastening machines and craned to a third station where the manual tacks are removed and the parts are prepped for final wing box assembly. With the advent of electromagnetic riveting (EMR) and the traveling yoke assembly machine this traditional approach has been replaced with single station processing. Wing panels and spars can now be automatically tacked together under continuous clamp up in their assembly jigs using EMR. This eliminates the requirement for disassembly, debur and cleaning required with the manual process.

Few data are available on biodegradation rates of materials over the long-term (more than 30 days). This information is necessary to conduct trade studies (studies used to make selections between alternatives) comparing various degrees of biodegradation versus combining biodegradation with incineration for advanced life support (ALS) systems. This paper describes the extreme case in which solids are degraded only by biodegradation. Data on biodegradation of insoluble solids from inedible parts of tomato plants are fitted to single and double exponential decay models to obtain half-life estimates for these materials. The data were obtained from batch experiments of material degradation over a 128-day period using mixed microbial cultures including activated sludge and an inoculum of Phanaerochaete Chrysosporium, a fungus known for its ability to degrade lignin.

The removal of dissolved ions from waste water is essential for water repurification on long-term human space missions. Lynntech, Inc., has demonstrated a novel electrochemically driven purification method using tubulated bipolar ion exchange membranes for the separation of dissolved inorganic impurities as well as charged organic species from waste water. Generally, electrochemical separation methods have limited applications since they can only be applied to the purification of water that has a sufficiently high dissolved ion content to make the water conductive. The novel tubulated bipolar membranes composed of bilayers of oppositely charged ionically conducting polymers can be used to overcome this limitation. This paper deals with the scaling-up of such a device to increase the throughput to process about 100 liters of waste water per day. This is achieved by using stacks of tubulated bipolar membranes.

The inedible portion of plant biomass in closed regenerative life support systems must be reprocessed producing recyclable by-products such as carbon dioxide, sugars, and other useful organic species. High solids biomass slurries containing up to 27 wt% were successfully prepared in a stirred batch reactor and then pumped using a single piston valveless pump. Wheat straw, potato, and tomato crop residues were acid hydrolyzed using 1.2 wt% sulfuric acid at 180°C and 1.2 MPa for 0.75-1.5 hours. Viscosity for a 25 wt% acid hydrolyzed wheat straw emulsion (Bingham-plastic) was 6.5 centipoise at 3 cm/sec and 25°C.

As ALS goals branch out to extended missions to the moon and Mars, concurrent science and engineering projects take center stage in the development of new ALS technology. It is necessary to optimize the interdisciplinary research activities in order to ensure ALS research goals are met in a timely manner, and to guarantee the reliability of future long term missions. The SSM team of the NJ-NSCORT has developed an internet software platform capable of performing a systems level analysis of the ALS research activity. The information produced by the analysis can assist ALS researchers in the streamlining of research activity.

A new software tool, MELISSA, has been developed for the simulation of life-support systems and other network-type subsystems. MELISSA features an intuitive graphical modeling environment and interactive simulation execution. Applications of MELISSA range from the analysis and validation of new ECLSS designs, to parametric optimization studies, to failure mode effects and criticality analysis of life-support systems. Additionally, MELISSA can be employed for training ECLSS developers and users, and as a teaching tool for lectures and seminars on systems design. As a demonstration, an ECLSS similar to the one of the International Space Station has been modeled and simulated.

Drinking water aboard spacecraft and on earth must be monitored to ensure that harmful bacteria are absent. NASA needs rapid methods for this purpose, to avoid possible launch delays and limit potential water-related health risks aboard spacecraft on orbit. Determination of bacterial viability after exposure to disinfection has significant health importance since oxidatively injured pathogenic bacteria have been shown to retain their virulence. This problem is compounded by the observation that injured bacteria are recovered at significantly lower frequencies using standard agar plate assays, leading to an underestimation of infection risks. Escherichia coli O157:H7 was exposed to 0.5 ppm free chlorine, retained on membrane filters and tested for physiological activity using a variety of assays.

Experiment T2, carried out during the EUROMIR'95 mission, demonstrated that microbial contamination can be directly monitored on board, thanks to innovative sampling and analysis methods. After flight, part of T2 downloaded samples were analysed by a method based on polymerase chain reaction (PCR). The analyses were aimed at quantifying both bacteria and fungi on the same sample. Although this activity was initially considered a simple adjustment of the PCR technique, the dramatic originality of its features was soon clear, especially due to partial readiness or unavailability of suitable tools and information. Work and results are described in the paper. A sensitivity of one micro-organism per sample was obtained, with bacteria and fungi detected in the same sample.

Over the last three years, the University of Utah (UofU), NASA Ames Research Center (ARC), and Reaction Engineering International (REI) have been developing an incineration system for the regeneration of components in waste materials for long-term life support systems. The system includes a fluidized bed combustor and a catalytic flue gas clean up system. An experimental version of the incinerator was built at the UofU. The incinerator was tested and modified at ARC and then operated during the Phase III human testing at NASA Johnson Space Center (JSC) during 1997. This paper presents the results of the work at the three locations: the design and testing at UofU, the testing and modification at ARC, and the integration and operation during the Phase III tests at JSC.

This paper offers a concept for a regenerable, low-power system for purifying exhaust from a solid waste processor. The innovations in the concept include the use of a closed-loop regeneration cycle for the adsorber, which prevents contaminants from reaching the breathable air before they are destroyed, and the use of a humidity-swing desorption cycle, which uses less power than a thermal desorption cycle and requires no venting of air and water to space vacuum or planetary atmosphere. The process would also serve well as a trace contaminant control system for the air in the closed environment. A systems-level design is presented that shows how both the exhaust and air purification tasks could be performed by one processor. Data measured with a fixed-bed apparatus demonstrate the effects of the humidity swing on regeneration of the adsorbent.

A volatile organic analyzer (VOA), developed by Graseby Dynamics, Ltd. under contract to the Johnson Space Center Toxicology Laboratory, is the core instrument for trace contaminant monitoring on the International Space Station (ISS). The VOA will allow trace amounts of target compounds to be analyzed in real time so that ISS air quality can be assessed in nominal and contingency situations. Recent events on Mir have underscored the need for real-time analysis of air quality so that the crew can respond promptly during off-nominal conditions. The VOA, which is based on gas chromatography/ion mobility spectrometry, is the first spacecraft instrument to be used for such a complex task. Consequently, a risk mitigation experiment (VOA/RME) was flown to assess the performance and engineering aspects of the VOA. This paper is a review of VOA/RME results from the STS-81 and STS-89 flights and their implications for the ISS VOA design and operations.