E-Waste Stream Analysis and Design Implications

The problem addressed in this paper is that the incoming stream of “feedstock” from product take-back systems is known to be widely variable, but the type and extent of that variability have not been well defined. This paper presents an analysis of data from an incoming e-waste stream for a computer refurbisher, and analyzes the type and degree of variability. The implications for design for sustainability are presented, along with a discussion of suggested future research needs.

Sustainable Distribution Design: Contrasting Disposable, Recyclable, and Reusable Strategies for Packaging Materials Using a Total Cost Analysis With an Illustration of Milk Distribution

Engineers, policy makers, and managers have shown increasing interest in increasing the sustainability of products over their complete lifecycles and also from the ‘cradle to grave’ or from production to the disposal of each specific product. However, a significant amount of material is disposed of in landfills rather than being reused in some form. A sizeable proportion of the products being dumped in landfills consist of packaging materials for consumable products. Technological advances in plastics, packaging, cleaning, logistics, and new environmental awareness and understanding may have altered the cost structures surrounding the lifecycle use and disposal costs of many materials and products resulting in different cost-benefit trade-offs. An explicit and well-informed economic analysis of reusing certain containers might change current practices and results in significantly less waste disposal in landfills and in less consumption of resources for manufacturing packaging materials. This work presents a method for calculating the costs associated with a complete process of implementing a system to reuse plastic containers for food products. Specifically, the different relative costs of using a container and then either disposing of it in a landfill, recycling the material, or reconditioning the container for reuse and then reusing it are compared explicitly. Specific numbers and values are calculated for the case of plastic milk bottles to demonstrate the complicated interactions and the feasibility of such a strategy.

Coordination of Complex Product Development Processes

Product development processes of complex products are complex themselves and particularly difficult to plan and manage effectively. Although many organizations manage their product development processes by monitoring the status of documents that are created as deliverables, in fact the progress of the process is in large part based on the actual information flow which is required to develop the product and produce the documents. A vital element in making product development processes work well is the correct understanding of how information flows and how to facilitate its development. In this paper we describe an executable stochastic model of the product development process that incorporates the salient features of the interplay between the information development, exchange and progress of the technical work. Experiments with the model provide insight into the mechanisms that drive these complex processes.

Environmental Analysis of Consumer Products During the Conceptual Phase of Product Design

This paper describes efforts taken to further transition life cycle analysis techniques from the latter, more detailed phases of design, to the early-on conceptual phase of product development. By using modern design methodologies such as automated concept generation and an archive of product design knowledge, known as the Design Repository, virtual concepts are created and specified. Streamlined life cycle analysis techniques are then used to determine the environmental impacts of the virtual concepts. As a means to benchmark the virtual results, analogous real-life products that have functional and component similarities are identified. The identified products are then scrutinized to determine their material composition and manufacturing attributes in order to perform an additional round of life cycle analysis for the actual products. The results of this research show that enough information exists within the conceptual phase of design (utilizing the Design Repository) to reasonably predict the relative environmental impacts of actual products based on virtual concepts.

A Systematic Methodology for Accurate Design-Stage Estimation of Energy Consumption for Injection Molded Parts

Today’s ubiquitous use of plastics in product design and manufacturing presents significant environmental and human health challenges. Injection molding, one of the most commonly used processes for making plastic products, consumes a significant amount of energy. A methodology for accurately estimating the energy consumed to injection-mold a part would enable environmentally conscious decision making during the product design. Unfortunately, only limited information is available at the design stage. Therefore, accurately estimating energy consumption before the part has gone into production can be challenging. In this paper, we describe a methodology for energy estimation that works with the limited amount of data available during the design stage, namely the CAD model of the part, the material name, and the production requirements. The methodology uses this data to estimate the parameters of the runner system and an appropriately sized molding machine. It then uses these estimates to compute the machine setup time and the cycle time required for the injection molding operation. This is done by appropriately abstracting information available from the mold flow simulation tools and analytical models that are traditionally used during the manufacturing stage. These times are then multiplied by the power consumed by the appropriately sized machine during each stage of the molding cycle to compute the estimated energy consumption per part.

Service Flow Simulation Using Scene Transition Nets (STN) Including Satisfaction-Attribute Value Functions

A new academic field, “service engineering” has emerged; it involves active investigation for increasing the productivities of service industries. However, there are only a few effective tools for the simulation and evaluation of complex services that have been designed using concepts from the field of service engineering. To overcome this shortcoming, the authors propose a multi-agent service flow simulation method using scene transition nets (STNs) that is a very useful graphical modeling and simulation method for application to discrete-continuous hybrid systems. This method treats services as complicated multi-agent and hybrid systems similar to manufacturing systems. To obtain realistic values of customer satisfaction, the authors input satisfaction-attribute value (S-AV) functions, which are often used in service engineering in service flow models using STN. This method visualizes discrete flows of services and temporal changes in the values of customer satisfaction and various other variables of service models. The authors present the results of the simulation of an online DVD rental service involving multiple agents to show the effectiveness of the proposed method that uses an STN GUI simulator developed by them.

A Study on Situated Cognition: Product Dissection’s Effect on Redesign Activities

Situation cognition theory describes the context of a learning activity’s effect on learner’s cognition. In this paper, we use situated cognition theory to examine the effect of product dissection on product redesign activities. Two research questions were addressed: 1) Does situated cognition, in the form of product dissection, improve product functionality during redesign exercise?, and 2) Does situation cognition, again in the form of product dissection, affect the creativity of product redesigns? In this study, three sections of first year students in two different locations — The Pennsylvania State University (Penn State) and Missouri University of Science and Technology (S&T) — performed product redesign using either an electric toothbrush or a coffee maker. The redesigned products have been analyzed with respect to both depth (detail level) and creativity.

Service Information for Product Quality

Engineering products go through 4 stages of lifecycle; design, production, use, and disposal. Engineers have developed tools for avoiding design flaws that cause troubles in the later stages. Accidents and malfunctions, however, still happen and some are even catastrophic. Once in the market, products require service. Whether scheduled, or unexpected, service is mostly carried out by subsidiaries of the manufacturer or sometimes unrelated specialists. When product troubles occur, service companies tend to seek solutions within their own organization without going back to the design stage. This approach may prove less costly, however, quick fixes may lead to disasters. Industries currently lack effective ways of feeding service information back to design. We analyzed some real accidents that took place in Japan where hard work in the use stage triggered the events. Information from the use stage to design will prevent accidents and also improve design to closely model reality.

Incorporating Cost and Resource Efficiency Into the Development of Green Recycling Technologies

The development of cost-effective and green recycling technologies for secondary metal recovery from industrial wastes is one of the new challenges on the sustainable development agenda. By incorporating cost and resource efficiency assessment into the technology innovation process, we aim to improve the sustainability of new recycling technologies by minimizing process waste, improving resource efficiency, thus reducing the recovery process cost. This paper focuses on modeling and assessing the production cost and resource use efficiency for closed-loop nickel recovery from spent hydrogenation catalysts. The engineering economics factors and process variables that affect the profitability and resource efficiency of nickel recovery are identified. They are modeled in cost and efficiency metrics. Model-based scenarios assessment revealed that compared to open-loop nickel recovery, the closed-loop concept delivers more cost-effective and greener recycling solutions. The closed-loop process cost reduction via efficient resource use and process waste minimization is in the range of 18.4% to 24.0% compared to the open-loop process option.

A Conflict Detection Approach for Collaborative Management of Product Interfaces

In complex products, maintaining subsystem consistency throughout the design process is often a time-consuming process of document exchange among cooperating functions. This paper describes a conflict management approach that lead to the computer-aided management of the product specification conflicts that happen due to the integration of subsystems. In order to define a framework, a systematic interface representation which proposes building generic interface schemes for subsystem connectivity representation is described. Based on this methodology, a functional architecture of the proposed conflict management method, along with generic exception taxonomy of conflicts is developed. The applicability of the proposed concepts is discussed through illustrative examples. The proposed methodology is intended to allow automatic detection and handling of interface connectivity errors throughout collaborative design processes.