Strategies for reducing energy demand in the materials sector

Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Materials Science and Engineering, 2013.This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.Cataloged from student-submitted PDF version of thesis.Includes bibliographical references (p. 155-175).This research answers a key question - can the materials sector reduce its energy demand by 50% by 2050? Five primary materials of steel, cement, aluminum, paper, and plastic, contribute to 50% or more of the final energy use and CO₂ emissions by industry, and thus are of primary focus. Both technical and demand-side strategies are evaluated to conclude that halving energy demand by 2050 is unlikely given the limitations governed by thermodynamics, scrap availability, and producer/consumer preferences, however some of the strategies analyzed offer encouraging opportunities and should be pursued. The thesis starts with understanding the evolution of material demand as society transforms from a developing to a developed economy. Economic scopes of global, USA, China, and India are assessed. The evolution trends are starkly different. The US shows strong signs of saturation while; both developing economies of China and India do not. The actors of material demand are analyzed to determine what is driving the difference. Results show that consumer income and population have been consistently increasing, but in the second half of the 20th century, the US industry has demanded less material per dollar output, while the US industry output has continued to grow. Collectively they tend to cancel each other, presenting a material saturation phenomenon. For China and India not only is the industry income and industry share of GDP growing, for each unit value addition, industry has continued to demand more material, avoiding demand saturation. One major way to reduce energy used for materials is to decrease the energy intensity of material production. Four technology based strategies are investigated without regard to cost: 1) widespread application of best available technology (BAT), 2) BAT to cutting edge technologies, 3) aggressive recycling, and finally, 4) significant improvements in recycling technologies. Taken together these aggressive strategies could produce impressive gains, on the order of a 20% reduction in energy relative to 2005, but well short of the goal of 50% reduction. Ultimately, we face fundamental thermodynamic and scrap availability constraints. Thus reducing material demand without compromising any service (called "material efficiency") is outlined as an approach to solving this dilemma. One way to increase material efficiency is use products for longer. Remanufacturing can support this by bringing used products back to like-new condition. Remanufactured products that substitute for new products are claimed to save energy. This comes from only looking at the materials production and manufacturing phases of the life cycle. However, when the use phase is included, the situation can change radically. For the 25 product cases we analyzed, 8 cases clearly saved energy, 6 did not, and 11 were too close to call. The drivers for this difference are explained. Thus the energy saving potential of remanufacturing seems complex and uncertain, especially given the trend of powering up of products followed by improvement of their energy efficiencies. As a result focusing remanufacturing efforts on passive products is recommended. Thus scalable material efficiency strategies need to be discovered. However even with the optimistic energy efficiency strategies deployed, in order to achieve the targets, demand increase for the materials needs to be restricted to under 25% of 2005 quantities. This entails that by 2050 we would need to reduce global demand per capita by 10% of today's global average and by 70% of today's US average which is an insurmountable task. Material efficiency strategies hold an impressive technical potential but face severe economic and behavioral challenges that future research needs to overcome.by Sahil Sahni.Ph.D

A functional genomic approach to actionable gene fusions for precision oncology

Fusion genes represent a class of attractive therapeutic targets. Thousands of fusion genes have been identified in patients with cancer, but the functional consequences and therapeutic implications of most of these remain largely unknown. Here, we develop a functional genomic approach that consists of efficient fusion reconstruction and sensitive cell viability and drug response assays. Applying this approach, we characterize similar to 100 fusion genes detected in patient samples of The Cancer Genome Atlas, revealing a notable fraction of low-frequency fusions with activating effects on tumor growth. Focusing on those in the RTK-RAS pathway, we identify a number of activating fusions that can markedly affect sensitivity to relevant drugs. Last, we propose an integrated, level-of-evidence classification system to prioritize gene fusions systematically. Our study reiterates the urgent clinical need to incorporate similar functional genomic approaches to characterize gene fusions, thereby maximizing the utility of gene fusions for precision oncology

Influence of process parameters on the synthesis of nano-titania by sol-gel route

Nano-rutile-titania has been synthesized via a sol-gel route using titanium tetra n-butoxide as the precursor and ethyl alcohol as the solvent at a low temperature of 80 °C. When synthesized with HCl as the catalyst, the powders crystallized without calcination, while the materials prepared using acetylacetone as the catalyst required heating to ~300 °C to initiate the crystallization. The anatase to rutile transformation temperature decreased with increasing water content

Reusing Personal Computer Devices - Good or Bad for the Environment?

The energy saving potential of reusing / reselling personal computer (PC) devices was evaluated relative to the choice of buying new. Contrary to the common belief of reuse leading to energy savings, with the advent of more efficient laptops and liquid crystal displays (LCD), reuse of an old personal computer device can lead to relative energy expenditure. We found that in certain scenarios this expenditure could be as large as 300% of the lifecycle energy inventory for the new device. As a result, it is essential to assess the reuse of personal computer devices more critically, incorporating the different factors that influence the analysis as discussed below.MIT-Singapore AllianceMIT Energy Initiative (MITEI

Appliance remanufacturing and life cycle energy and economic savings

In this paper we evaluate the energy and economic consequences of appliance remanufacturing relative to purchasing new. The appliances presented in this report constitute major residential appliances: refrigerator, dishwasher, and clothes washer. The results show that, despite savings achieved in production, appliance remanufacturing is a net energy-expending end-of-life alternative. Moreover, we find that economic incentives can be an influential driver for consumers to remanufacture and re-use old appliances.Massachusetts Institute of Technology. Energy InitiativeSingapore-MIT Alliance for Research and Technolog

Decoupling the correlation between cytotoxic and exhausted T lymphocyte states enhances melanoma immunotherapy response prediction

Summary: Cytotoxic T lymphocyte (CTL) and terminal exhausted T lymphocyte (ETL) activities crucially influence immune checkpoint inhibitor (ICI) response. Despite this, the efficacy of ETL and CTL transcriptomic signatures for response prediction remains limited. Investigating this across the TCGA and publicly available single-cell cohorts, we find a strong positive correlation between ETL and CTL expression signatures in most cancers. We hence posited that their limited predictability arises due to their mutually canceling effects on ICI response. Thus, we developed DETACH, a computational method to identify a gene set whose expression pinpoints to a subset of melanoma patients where the CTL and ETL correlation is low. DETACH enhances CTL’s prediction accuracy, outperforming existing signatures. DETACH signature genes activity also demonstrates a positive correlation with lymphocyte infiltration and the prevalence of reactive T cells in the tumor microenvironment (TME), advancing our understanding of the CTL cell state within the TME