Life cycle assessment of materials and construction in commercial structures : variability and limitations

Thesis (M. Eng.)--Massachusetts Institute of Technology, Dept. of Civil and Environmental Engineering, 2010.Cataloged from PDF version of thesis.Includes bibliographical references (p. 48-50).Life cycle assessment has become an important tool for determining the environmental impact of materials and products. It is also useful in analyzing the impact a structure has over the course of its life cycle. The International Organization of Standardization's 14040 series specifies how to perform a formal life cycle assessment in which the materials, construction, use, and demolition of a building are quantified into embodied energy and carbon dioxide equivalents, along with representation of resource consumption and released emissions. These results are useful to architects, structural engineers, contractors, and owners interested in predicting environmental impacts throughout a structure's life. Although many life cycle assessments have already been performed on various types of structures, most have occurred outside the United States. The life cycles of American buildings must be better understood before their environmental impact can be reduced. Regional variations also must be taken into account. Most existing studies have a variety of focuses, which makes them difficult to compare to one another, and they do not examine a wide enough range of buildings. This thesis quantifies the variability of building life cycle assessments by examining existing studies' differences and comparing them to a new study conducted using GaBi software. The new model assesses the carbon dioxide equivalents of one ton of structural steel, in three different forms, and one ton of reinforced concrete, in three different mixes. Impact assessment is performed using two widely accepted methods. The results from this thesis can be used to standardize and improve the study of typical commercial structures across different regions of the United States.by Sophia Lisbeth Hsu.M.Eng

Improving the quality and transparency of building life cycle assessment

Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Architecture, 2011.Cataloged from PDF version of thesis.Includes bibliographical references (p. 54-60).Life cycle assessment, or LCA, is a powerful method for measuring and reducing a building's environmental impacts. Its widespread adoption among designers would allow the environmental component of sustainability to gain more traction in design philosophy and client goals. Currently, the stakeholders in building design-both design professionals and clients-have few resources for proper LCA education and use, and there are no common metrics agreed upon for reporting the results of LCAs for buildings. This thesis assesses the strengths and weaknesses of resources available to design practitioners for performing LCA, including a pilot credit in the United States Green Building Council's Leadership in Energy and Environmental Design ratings system. A case study performs an LCA comparing two structural materials in an office building. The study aims to be as transparent and repeatable as possible, in order to set a good example on which to model future building LCAs. Based on the critical review of LCA resources and the lessons learned from the case study, eight key points are proposed for improving the quality and transparency of building life cycle assessment projects.by Sophia Lisbeth Hsu.S.M

Early Gadolinium Enhancement for Area at Risk Determination: A Preclinical Validation Study

Objectives—The aim of this study was to determine if early gadolinium enhancement (EGE) by cardiovascular magnetic resonance (CMR) imaging in a canine model of reperfused myocardial infarction depicts the area at risk (AAR) as determined by microsphere blood flow analysis. Background—It remains controversial whether only the irreversibly injured myocardium enhances when performing CMR imaging in the setting of acute myocardial infarction. Recently, EGE has been proposed as a measure of the AAR in acute myocardial infarction as it correlates well with T2-weighted imaging of the AAR, but still requires pathological validation. Methods—Eleven dogs underwent 2 hours of coronary artery occlusion and 48 hours of reperfusion prior to imaging at 1.5T. EGE imaging was performed 3 minutes after contrast administration with coverage of the entire left ventricle. Late gadolinium enhancement (LGE) imaging was performed between 10 and 15 minutes after contrast injection. AAR was defined as myocardium with blood flow (mL/min/g) \u3c 2SD from remote myocardium determined by microspheres during occlusion. The size of infarction was determined using triphenyltetrazolium chloride (TTC). Results—There was no significant difference in the size of enhancement by EGE compared to the size of AAR by microspheres (44.1± 15.8% vs. 42.7± 9.2%, p=0.61) with good correlation (r=0.88, p \u3c 0.001) and good agreement by Bland-Altman analysis (mean bias 1.4± 17.4%). There was no difference in the size of enhancement by EGE compared to enhancement on native T1 and T2 maps. The size of EGE was significantly greater than the infarct by TTC, (44.1± 15.8% vs. 20.7± 14.4%, p \u3c 0.001) and LGE (44.1± 15.8% vs. 23.5± 12.7%, p \u3c 0.001). Conclusion—At three minutes post-contrast, EGE correlated well with the AAR by microspheres and CMR, and was greater than infarct size. Thus, EGE enhances both reversibly and irreversibly injured myocardium

Transimperial Networks: East Asia and the ‘Victorian’ World: Introduction

Traditionally, East Asia has been on the margins of Victorian Studies, eclipsed by sites of formal imperialism such as South Asia. However, the region was deeply intertwined with the “Victorian” world through transimperial networks of trade, migration, and geopolitical competition. Rather than locating East Asia at the margins, this cluster of lesson plans explores the figurative and historical centrality of East Asia to Victorian Studies

PepMLM: Target Sequence-Conditioned Generation of Peptide Binders via Masked Language Modeling

Target proteins that lack accessible binding pockets and conformational stability have posed increasing challenges for drug development. Induced proximity strategies, such as PROTACs and molecular glues, have thus gained attention as pharmacological alternatives, but still require small molecule docking at binding pockets for targeted protein degradation (TPD). The computational design of protein-based binders presents unique opportunities to access undruggable targets, but have often relied on stable 3D structures or predictions for effective binder generation. Recently, we have leveraged the expressive latent spaces of protein language models (pLMs) for the prioritization of peptide binders from sequence alone, which we have then fused to E3 ubiquitin ligase domains, creating a CRISPR-analogous TPD system for target proteins. However, our methods rely on training discriminator models for ranking heuristically or unconditionally-derived guide peptides for their target binding capability. In this work, we introduce PepMLM, a purely target sequence-conditioned de novo generator of linear peptide binders. By employing a novel masking strategy that uniquely positions cognate peptide sequences at the terminus of target protein sequences, PepMLM tasks the state-of-the-art ESM-2 pLM to fully reconstruct the binder region, achieving low perplexities matching or improving upon previously-validated peptide-protein sequence pairs. After successful in silico benchmarking with AlphaFold-Multimer, we experimentally verify PepMLM's efficacy via fusion of model-derived peptides to E3 ubiquitin ligase domains, demonstrating endogenous degradation of target substrates in cellular models. In total, PepMLM enables the generative design of candidate binders to any target protein, without the requirement of target structure, empowering downstream programmable proteome editing applications

Transimperial Networks and East Asia: Timeline

To help instructors and students who may be unfamiliar with the history of East Asia and its transimperial exchanges with the Anglophone world, the creators of the “Transimperial Networks and East Asia” lesson plan cluster built this timeline, which includes some major historical events from the fifteenth to the twentieth century. This timeline comes out of our many discussions about the methodological issues that arise when the field of Victorian Studies seeks to expand its traditional geographical scope. As we quickly realized in the process of creating our cluster, the usual boundaries of the long nineteenth century (the French Revolution to World War I) are too limited and Eurocentric for the transimperial connections our lesson plans examine. Thus, we offer this timeline both to orient instructors and students and to illustrate how centering East Asia calls into question our field’s most basic assumptions

Energy-effective Predictive Temperature Control for Soy Mash Fermentation Based on Compartmental Pharmacokinetic Modelling

Compartment modelling has been successfully used in pharmacokinetics to describe the kinetics of drug distribution in body tissues. In this study, the technique is adopted to describe the dynamics of temperature response and energy exchange in a soy mash fermentation system. The objective is to provide a precise temperature-controlled atmosphere for effective fermentation with the premise of energy saving. In analogy to pharmacokinetics, water and mash tanks are treated as compartments, energy flow as drug delivery, and the temperature as the drug concentration in a specific compartment. The model allows us to estimate the time of injecting a certain amount of energy to a specific tank (compartment) in a cost-effective way. Thus, model-based temperature control and energy management can be possible