Evaluating electronic waste recycling systems : the influence of physical architecture on system performance

Thesis (S.M. in Technology and Policy)--Massachusetts Institute of Technology, Engineering Systems Division, Technology and Policy Program, 2008.This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.Includes bibliographical references (p. 63-68).Many different forms of electronic waste recycling systems now exist worldwide, and the amount of related legislation continues to increase. Numerous approaches have been proposed including landfill bans, extended producer responsibility (EPR) and advance recovery fee (ARF) funded recycling systems. In order for policymakers and system architects to establish the optimal recycling system for their location, they need to know how to evaluate the performance of existing systems, and furthermore, how to use this information to design new systems. This thesis addresses the question: How does the physical system architecture of e-waste systems influence system performance? Specifically, it focuses upon the physical system architecture of collection site density and distribution. This thesis presents a systematic methodology developed with the Materials Systems Laboratory for characterizing recycling systems. Case studies of existing e-waste systems operating in Switzerland, Sweden, the Netherlands, Norway, Belgium, the Canadian province of Alberta and the US States of California, Maine and Maryland are examined for correlations between the environmental and financial performance of existing systems with respect to both the context and the architectural options of those systems. The case study analysis furthermore informs the construction of a model of e-waste systems. This model, which examines architectural choices in collection, transport, processing and system management of e-waste, is used to predict the environmental and financial performance of theoretical e-waste systems for a given location. The model was intentionally developed to be both broad, in order to encompass all pieces of recycling systems, and general, such that many different types of systems, both real and hypothetical, can be analyzed. Following an application of the model to several different combinations of system architecture and context, policy recommendations are made regarding the construction and evaluation of e-waste systems in various locations.by Susan Fredholm.S.M.in Technology and Polic

Policy Issues in Implementing Smart Cards in Urban Public Transit Systems

Many public transportation institutions have been discarding their magnetic strip payment cards or traditional cash-based fee collection systems in favor of automated fare collection systems with smart card technology. Smart cards look like traditional credit cards or ID cards; however, using RFID technology, they allow for contactless payment and identification. Smart cards are becoming increasingly popular among transit agencies primarily because they are convenient for customers, reduce administrative costs for transit agencies, and have the potential of improving the performance of complex transit systems overall. The increased availability and affordability of contactless cards has also contributed to this trend in adoption

A Ketogenic Diet Suppresses Seizures in Mice through Adenosine A1 Receptors

A ketogenic diet (KD) is a high-fat, low-carbohydrate metabolic regimen; its effectiveness in the treatment of refractory epilepsy suggests that the mechanisms underlying its anticonvulsive effects differ from those targeted by conventional antiepileptic drugs. Recently, KD and analogous metabolic strategies have shown therapeutic promise in other neurologic disorders, such as reducing brain injury, pain, and inflammation. Here, we have shown that KD can reduce seizures in mice by increasing activation of adenosine A1 receptors (A1Rs). When transgenic mice with spontaneous seizures caused by deficiency in adenosine metabolism or signaling were fed KD, seizures were nearly abolished if mice had intact A1Rs, were reduced if mice expressed reduced A1Rs, and were unaltered if mice lacked A1Rs. Seizures were restored by injecting either glucose (metabolic reversal) or an A1R antagonist (pharmacologic reversal). Western blot analysis demonstrated that the KD reduced adenosine kinase, the major adenosine-metabolizing enzyme. Importantly, hippocampal tissue resected from patients with medically intractable epilepsy demonstrated increased adenosine kinase. We therefore conclude that adenosine deficiency may be relevant to human epilepsy and that KD can reduce seizures by increasing A1R-mediated inhibition

Impaired NDRG1 functions in Schwann cells cause demyelinating neuropathy in a dog model of Charcot-Marie-Tooth type 4D

Mutations in the N-myc downstream-regulated gene 1 (NDRG1) cause degenerative polyneuropathy in ways that are poorly understood. We have investigated Alaskan Malamute dogs with neuropathy caused by a missense mutation in NDRG1. In affected animals, nerve levels of NDRG1 protein were reduced by more than 70% (p < 0.03). Nerve fibers were thinly myelinated, loss of large myelinated fibers was pronounced and teased fiber preparations showed both demyelination and remyelination. Inclusions of filamentous material containing actin were present in adaxonal Schwann cell cytoplasm and Schmidt-Lanterman clefts. This condition strongly resembles the human Charcot-MarieTooth type 4D. However, the focally folded myelin with adaxonal infoldings segregating the axon found in this study are ultrastructural changes not described in the human disease. Furthermore, lipidomic analysis revealed a profound loss of peripheral nerve lipids. Our data suggest that the low levels of mutant NDRG1 is insufficient to support Schwann cells in maintaining myelin homeostasis. (C) 2020 The Author(s). Published by Elsevier B.V. This is an open access article under the CC BY license

Analyses of pig genomes provide insight into porcine demography and evolution

For 10,000 years pigs and humans have shared a close and complex relationship. From domestication to modern breeding practices, humans have shaped the genomes of domestic pigs. Here we present the assembly and analysis of the genome sequence of a female domestic Duroc pig (Sus scrofa) and a comparison with the genomes of wild and domestic pigs from Europe and Asia. Wild pigs emerged in South East Asia and subsequently spread across Eurasia. Our results reveal a deep phylogenetic split between European and Asian wild boars ∼1 million years ago, and a selective sweep analysis indicates selection on genes involved in RNA processing and regulation. Genes associated with immune response and olfaction exhibit fast evolution. Pigs have the largest repertoire of functional olfactory receptor genes, reflecting the importance of smell in this scavenging animal. The pig genome sequence provides an important resource for further improvements of this important livestock species, and our identification of many putative disease-causing variants extends the potential of the pig as a biomedical model

Is Economic value an Effective Proxy for Embodied Energy and Environmental Impact in Material Systems?

This paper uses economic value metrics to evaluate the retention of value of secondary materials and provides a framework for characterizing value throughout a material and product life-cycle. These economic value metrics are compared with analogous life cycle assessment metrics in order to determine the conditions under which economic value effectively represents environmental impact for EoL material recovery decision-makers. A comparison of these metrics using several different material types indicates that there is a strong correlation between LCA metrics and economic value metrics for most of the materials studied. However, there were a few cases in which the economic value metrics were poor indicators of the LCA metrics

Actions of adenosine at its receptors in the CNS insights from knockouts and drugs

International audienceAdenosine and its receptors have been the topic of many recent reviews. These reviews provide a good summary of much of the relevant literature--including the older literature. We have, therefore, chosen to focus the present review on the insights gained from recent studies on genetically modified mice, particularly with respect to the function of adenosine receptors and their potential as therapeutic targets. The information gained from studies of drug effects is discussed in this context, and discrepancies between genetic and pharmacological results are highlighted

Actions of adenosine at its receptors in the CNS insights from knockouts and drugs

International audienceAdenosine and its receptors have been the topic of many recent reviews. These reviews provide a good summary of much of the relevant literature--including the older literature. We have, therefore, chosen to focus the present review on the insights gained from recent studies on genetically modified mice, particularly with respect to the function of adenosine receptors and their potential as therapeutic targets. The information gained from studies of drug effects is discussed in this context, and discrepancies between genetic and pharmacological results are highlighted

Modeling the Impact of Product Portfolio on the Economic and Environmental Performance of Recycling Systems

hrough the development of a general model of electronics recycling systems, the effect of product portfolio choices on economic and environmental system performance is explored. The general model encompasses the three main functions of a recycling system-collection, processing, and system management-and allows for the effect of both contextual and architectural inputs-including product scope-to be explored. Overall model results indicate that collecting a broader portfolio of products can be economically favorable, even for cases in which lower-value products are added to a recycling system. In these cases, the higher total mass throughputs that are realized by the collection of additional product types can help to drive down the cost per unit mass collected. Expanding product scope can also yield improvements in environmental performance, as the energy per unit mass collected can also decrease with higher mass throughputs