Manbir S. Sodhi

Models for recycling electronics end-of-life products

Abstract. Increasing environmental concerns about the disposal of mass produced products have resulted in efforts to take back end-of-life consumer products. Legislation aimed at forcing manufacturers to take back electronics products at the end of their useful lives has either been adopted or is impending in many countries. This, along with shrinking landfill capacity and the reluctance of communities to open new waste sinks underscores the importance of developing methods and models for the management of end-of-life materials and products. This paper reports a study of the reverse channels for recycling of electronics products. The economics of electronics recycling are modeled from the viewpoints of the generators, recyclers, and material processors separately. A variety of mathematical programming models, representative of the many ways in which the recycling industry currently operates, have been proposed along with numerical illustrations. Models integrating disassembly and material recovery decisions are also presented. These models can be used by recyclers and processors for optimizing recycling operations and thus contribute towards the economic sustainability of electronics recycling.Zusammenfassung. Zunehmende Berücksichtigung von Umweltgesichtspunkten bei der Abfallbehandlung hat zu einer Verstärkung der Bedeutung der Rücknahme von Altprodukten nach Ablauf ihrer Gebrauchsphase geführt. So wird in vielen Ländern durch gesetzgeberische Maßnahmen ein immer größerer Druck auf die Hersteller von Elektro- und Elektronikgeräten ausgeübt, ihre Erzeugnisse nach Ende ihrer Nutzungsdauer wieder zurück zu nehmen. Zugleich nehmen vorhandene Deponiekapazitäten zur Beseitigung solcher Produkte ab und es verringert sich die Neigung seitens der Gebietskörperschaften, neue Deponien zu eröffnen. Damit nimmt die Bedeutung der Entwicklung von Methoden und Modellen zum Management der Verwertung von Altprodukten in diesem Bereich immer mehr zu. Der vorliegende Beitrag befaßt ich mit der Untersuchung entsorgungslogistischer Aktivitäten im Rahmen des Recyclings von Elektronikschrott. Dabei werden die Planungsprobleme für ein ökonomisch vorteilhaftes Recycling getrennt aus der Sicht der Erzeuger, Entworger und Verwerter der Altprodukte modelliert. Zur Darstellung der Entscheidungsprobleme im Recyclingbereich wird eine Reihe von Modellen der Mathematischen Optimierung vorgestellt und mit numerischen Beispielen untermalt. Hierbei werden auch Modelle zur Integration von Demontage- und Verwertungsplanung repräsentiert. Solche Modelle können ebenso von Entsorgern wie von Verwertern zur Optimierung ihrer Recyclingaktivitäten genutzt werden.

A conceptual QFD planning model

Quality function deployment (QFD) is a structured approach to seek out customers, understand their needs, and ensure that their needs are met. QFD is probably the most important management tool developed to assure quality in new or improved products and services. As with any other tool, the quantum of benefits obtained from the use of QFD is proportional to the effectiveness of its use. To enhance the effectiveness and efficiency of QFD as a means to transfer the “voice of the customer” into design and production, a new comprehensive hierarchical framework for QFD planning process and a zero‐one goal programming model for the selection of design requirements are proposed. The hierarchical framework contributes to the strategic guidance and provides clear direction for QFD teams during the construction of the house of quality. The decision model assists in determining a set of design requirements that most effectively meet customer needs subject to limited resources and other organizational restrictions. An illustrative example is also provided to demonstrate the practical usage of the design selection model.

GLANCE ANALYSIS OF DRIVER EYE MOVEMENTS TO EVALUATE DISTRACTION

With the increasing use of in-vehicle devices in cars, an understanding of the safety implications of secondary tasks has become crucial. It is now possible to study the effects of many in-vehicle devices and tasks on driving by using head-mounted eye-tracking devices (HEDs) to collect eye positions and pupil diameters, which have been considered indicators of attentional focus. The collection of eye-position and pupil-diameter data of automobile drivers under on-road conditions and while completing various secondary tasks is described in this paper. Drivers were asked to drive on a preselected two-lane road for a total distance of 22 miles while gaze data were recorded using a HED. Longer off-road fixation durations were observed in radio-tuning and rearview mirror checking tasks, but not in the odometer checking task. In addition, the standard deviations of fixation displacements during a cognitive task involving the computation of a date for a meeting were shorter than those observed during normal driving.

On-road driver eye movement tracking using head-mounted devices

It is now evident from anecdotal evidence and preliminary research that distractions can hinder the task of operating a vehicle, and consequently reduce driver safety. However with increasing wireless connectivity and the portability of office devices, the vehicle of the future is visualized as an extension of the static work place - i.e. an office-on-the-move, with a phone, a fax machine and a computer all within the reach of the vehicle operator. For this research a Head mounted Eye-tracking Device (HED), is used for tracking the eye movements of a driver navigating a test route in an automobible while completing various driving tasks. Issues arising from data collection of eye movements during the completion of various driving tasks as well as the analysis of this data are discussed. Methods for collecting video and scan-path data, as well as difficulties and limitations are also reported.

Product Design for Disassembly and Bulk Recycling

Abstract The recycling of manufactured products depends greatly on the efficiency with which material can be separated from each other. For the long term, recycling can be made more effective by the design of products for greater use of disassembly and recycling. This requires the development of suitable product analysis tools to enable design teams to evaluate the ease of disassembly and recycling of alternative product concepts during the early stages of design. This paper describes the development of product analysis procedures for combined disassembly and bulk recycling such that consequences of material selection upon the end-of-life recovery of materials can be investigated.

Design for Bulk Recycling: Analysis of Materials Separation

Abstract Increased interest in the life cycle design of products has resulted in emphasis on the disassembly and recovery of materials at product end-of-life. For many products the cost of disassembly will outweigh the value of any materials recovered and such products will be processed by bulk recycling involving shredding and mechanical material separation. The efficiency of bulk recycling is influenced by a number of factors including the selection of materials during product design. This paper deals with the analysis of materials separation, which determines the least cost or maximum profit level of materials separation. This can be used for the evaluation of product designs for efficient bulk recycling and the combination of disassembly and bulk recycling.

Detecting Eye Movements in Dynamic Environments

To take advantage of the increasing number of in-vehicle devices, automobile drivers must divide their attention between primary (driving) and secondary (operating in-vehicle device) tasks. In dynamic environments such as driving, however, it is not easy to identify and quantify how a driver focuses on the various tasks he/she is simultaneously engaged in, including the distracting tasks. Measures derived from the driver’s scan path have been used as correlates of driver attention. This article presents a methodology for analyzing eye positions, which are discrete samples of a subject’s scan path, in order to categorize driver eye movements. Previous methods of analyzing eye positions recorded in a dynamic environment have relied completely on the manual identification of the focus of visual attention from a point of regard superimposed on a video of a recorded scene, failing to utilize information regarding movement structure in the raw recorded eye positions. Although effective, these methods are too time consuming to be easily used when the large data sets that would be required to identify subtle differences between drivers, under different road conditions, and with different levels of distraction are processed. The aim of the methods presented in this article are to extend the degree of automation in the processing of eye movement data by proposing a methodology for eye movement analysis that extends automated fixation identification to include smooth and saccadic movements. By identifying eye movements in the recorded eye positions, a method of reducing the analysis of scene video to a finite search space is presented. The implementation of a software tool for the eye movement analysis is described, including an example from an on-road test-driving sample.

Multiperiod tool and production assignment in flexible manufacturing systems

Flexible manufacturing systems (FMSs) are usually composed of general purpose machines with automatic tool changing and integrated material handling. FMSs offer the advantages of high utilization levels and simultaneous production of a variety of part types with minimal changeover time. Although the trend in FMS operation appears to be towards unmanned production, there is much diversity in the policies under which FMSs can be operated. These policies are governed to some extent by the available technological resources. In this paper several policies are described. Tool loading and production assignment models for setting production plans over a short term planning horizon when using these policies are then formulated. Heuristics for the solution of these models are detailed and computational results are presented.

Surface roughness monitoring using computer vision

In this paper, a comparative experimental surface roughness measurement method based on the speckle pattern caused by a laser beam on a rough surface is presented. Surfaces with known surface roughness are measured using this method to obtain a calibration curve. This information is used to measure surfaces produced by surface grinding, and the results compared with stylus measurements. The online use of this method for tracking the roughness of a workpiece being processed on a surface grinder and to monitor the condition of the grinding wheel is also reported.

Using tool life models to minimize processing time on a flexible machine

Economic tool life models are presented for machines with finite capacity tool magazines and variable processing speed capability. Single and multiple part models for minimizing the total throughput time are formulated as nonlinear, integer programs (NLIP). An algorithm is presented for the NLP relaxation and a marginal analysis approach for solving the NLIP is detailed, giving an optimal tool loading policy as well as the processing speeds for each of the part types so as to minimize the makespan. A numerical example illustrates the procedures.