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Technical Paper

Laser Processed Aluminum Surfaces in Automotive Applications: Performance Requirements for Cylinder Bores and Valve Seats

1998-08-11
982106
The emphasis automotive manufacturers have placed on lightweight, low-cost components has resulted in a number of custom-engineered materials which have outstanding properties. High temperature polymers and composites, low cost nickel-based alloys, and surface coatings are areas in which material development has lead to parts with improved performance at lower cost. This paper explores the feasibility of employing laser surface processing to provide better performance for two key engine applications, cylinder bores and valve seats. The Laser Induced Surface Improvement (LISI, patent-pending) technique developed at The University of Tennessee Space Institute, is a surface modification technique which can provide high quality surface layers. Example laboratory tests on processed aluminum substrates indicate that hardness and wear-resistance can be substantially improved.
Technical Paper

A Design of Internet-Based Remote Manufacturing System

1998-08-11
982110
This paper discusses a design of Internet-based remote manufacturing system, which would help a global company to centralize its production, to control and to monitor the operation from the remote sites. In our design, we describe our system in two main categories, which are the design system and the manufacturing system. In the design system, we use the Internet-based client-server architecture to allow multiple clients to design products collaboratively and simultaneously. After the design is finished, it will be sent to the manufacturing system. At this stage, the clients can control and monitor the process from geographically distributed locations via the Internet.
Technical Paper

Environmental Evaluation of Molding Exterior Body Panels in Color

1998-08-11
982121
Painting a vehicle's exterior is an energy and emission-intensive process. Molding exterior panels in color has the potential to reduce both environmental burdens and cost. This study compares the material and energy flows for painting exterior panels (one front and one rear fascia) with those for molding the panels in color at the Saturn manufacturing facility. Molding fascias in color requires the addition of 62,700 kg of color pellets to the injection molding process, but eliminates several painting steps. These changes would result in reducing paint consumption by 500,000 kg/yr, energy consumption by 133 million MJ and volatile organic compound (VOC) emissions by 150,000 kg/yr.
Technical Paper

Cluster vs. Linear Team Dynamics

1998-08-11
982123
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.
Technical Paper

Real-Time Exhaust Gas Flow Measurement System

1998-08-11
982105
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.
Technical Paper

Lean Manufacturing Design through Simulation Analysis

1998-08-11
982119
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.
Technical Paper

Flexible Simulation Modeling as a Mechanism to Pervasively Implement Simulation in the Automotive Industry

1998-08-11
982118
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.
Technical Paper

Simulation and Analysis of an Automotive Assembly Operation

1998-08-11
982117
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.
Technical Paper

The Environmental Aspects of Building the Saturn Plant

1998-08-11
982115
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.
Technical Paper

EPA MACT Rules for Surface Coating Operations

1998-08-11
982116
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.
Technical Paper

Method of Formulating Paint Through Color Space Modeling

1998-08-11
982114
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.
Technical Paper

The Role of Supplier Chain Management in Saturn Corporation's Environmental Performance

1998-08-11
982108
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.
Technical Paper

Wing Manufacturing: Next Generation

1998-07-31
985601
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.
Technical Paper

Modeling Long-Term Biodegradation of Inedible Plant Material

1998-07-14
981819
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.
Technical Paper

Design of an Electrochemical Tubulated Bipolar Membrane Breadboard System for the Treatment of Spacecraft Waste Water

1998-07-13
981755
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.
Technical Paper

Biomass Conversion to Pumpable Slurries

1998-07-13
981757
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.
Technical Paper

Object Oriented Tool for ALS Project Analysis on the Internet

1998-07-13
981753
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.
Technical Paper

MELISSA - A Graphical Environment for Life-Support Systems Simulation

1998-07-13
981754
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.
Technical Paper

Rapid Enumeration of Active Bacteria in Water After Disinfection

1998-07-13
981761
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.
Technical Paper

Microbial Contamination Monitoring of Space Stations: PCR Analysis for Downloaded Samples of EUROMIR'95 Experiment T2

1998-07-13
981762
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.
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