This dissertation broadly describes efforts related to materials discovery, design and optimization

using a first-principles approach based on density functional theory (DFT).

The two main application areas comprise transition-metal alloys and functional materials.

The research involving transition-metal alloys aims at finding cost-effective replacement

strategies for rhenium (Re). Elemental Re exhibits profuse deformation twinning under

mechanical loads and has a high ductility. It is shown that the twinning characteristics of

Re and its ductility are correlated with its anomalously low (11-21) twin-boundary energy.

The origin of this twin-energy anomaly is related to the presence of icosahedral structural

units on the (11-21) twin boundary. These structural units are stabilized near d-band fillings

corresponding to Re. The (11-21) twin-boundary energy can be lowered further by

decreasing the d-band filling with respect to elemental Re. This increases the intrinsic

ductility according to three independent ductility parameters employed in this work: i)

Pugh's ratio of bulk to shear modulus, ii) Yoo's ratio of surface to twin energy and iii) an

ideal-strength criterion. Based on new insights in the relation between d-band filling, defect

energies and intrinsic ductility, several candidate alloys for Re replacement are proposed.

Ru-based alloys with additions of Ta, W and Re are shown to be potential replacement

candidates. The last part of this dissertation describes high-throughput calculations that

have culminated in the two largest databases of elastic and piezoelectric tensor properties

available to-date. The workflow for doing such calculations is described, along with various

checks to ensure the accuracy of the calculated physical properties. The database with

elastic-tensor properties is expected to be of use in a number of fields where discovery of

new materials with desired values of elastic stiffness or (lattice) thermal conductivity are of

interest. Further, data mining and machine learning can be applied to better understand

elastic properties and their physical descriptors. Several novel piezoelectric materials are

discovered as part of this work. Some of these exhibit a high intrinsic piezoelectric response

and may serve as a starting point for a process in which the piezoelectric response is optimized

by alloying and microstructure engineering. As such, this database can support a search for future

replacement candidates of the widely used piezoelectric materials such as Pb(ZrxTi1?-x)O3 (PZT) that contain lead.

This dissertation applies tools developed in labor economics to empirically study questions in labor, development, and urban economics. Each chapter attempts to decompose a problem into competing explanations. The first decomposes racial segregation in US cities. The second decomposes differences in wages between agricultural workers and and non-agricultural workers. And finally, the last decomposes the heterogeneous responses of workers to a new monitoring technology.

In the first chapter, I revisit the question of whether residential segregationin US cities emerged in the mid-twentieth century as a consequence of decentralized location choices in combination with white antipathy toward black residents or whether it reflected institutionalized constraints on the availability of neighborhoods that black families could access. The chapter analyzes rich population data from the 1930 and 1940 censuses to disentangle these channels. I first lay out a simple discrete choice model of residential choices by white and black families that depends on the local price of housing and on the fraction of black residents in each neighborhood. I show how the preferences of both race groups can be identified using information on the impacts of exogenous inflows of white and black residents to different neighborhoods. White and black rural inflows constituted a major source of inmigration to major cities during this time period; I construct a pair of novel instrumental variables for these inflows by connecting the distributions of white and black surnames in rural areas to earlier migrants living in different census tracts in 1930. The resulting structural estimates confirm that white families had a relatively high willingness to pay to avoid black neighbors, consistent with an important role for preferences in the evolution of neighborhood segregation. Combining white and black preferences, however, I also find strong evidence that black residents faced supply side constraints on their neighborhood choices. I conclude that about one half of the overall degree of neighborhood segregation observed in 1940 was due to the different preferences of white and black families, while a comparable share was due to implicit or explicit constraints on which neighborhoods black families could move into.

While the first chapter interpreted incumbent residents' responses to migrants as reflective of their racial preferences, the second chapter, based on joint work with Marieke Kleemans, Joan Hamory Hicks, and Ted Miguel, directly studies the migrant experience itself. Recent research has pointed to large gaps in labor productivity between the agricultural and non-agricultural sectors in low-income countries, as well as between workers in rural and urban areas. Most estimates are based on national accounts or repeated cross-sections of micro-survey data, and as a result typically struggle to account for individual selection between sectors. We use long-run individual-level panel data from two low-income countries (Indonesia and Kenya). Accounting for individual fixed effects leads to much smaller estimated productivity gains from moving into the non-agricultural sector (or urban areas), reducing estimated gaps by over 80%. Estimated productivity gaps do not emerge up to five years after a move between sectors. We evaluate whether these findings imply a re-assessment of the conventional wisdom regarding sectoral gaps, discuss how to reconcile them with existing cross-sectional estimates, and consider implications for the desirability of sectoral reallocation of labor.

Finally, the third chapter is based on joint work with Ernesto Dal Bó, Frederico Finan, and Laura Schechter and empirically studies models of task assignment within organizations in a developing country context. Standard models of hierarchy assume that agents and middle managers are better informed than principals about how to implement a particular task. We estimate the value of the informational advantage held by supervisors (middle managers) when ministerial leadership (the principal) introduced a new monitoring technology aimed at improving the performance of agricultural extension agents (AEAs) in rural Paraguay. Our approach employs a novel experimental design that, before randomization of treatment, elicited from supervisors which AEAs they believed should be prioritized for treatment. We find that supervisors did have valuable information---they prioritized AEAs who would be more responsive to the monitoring treatment. We develop a model of monitoring under different allocation rules and roll-out scales (i.e., the share of AEAs to receive treatment). We semi-parametrically estimate marginal treatment effects (MTEs) to demonstrate that the value of information and the benefits to decentralizing treatment decisions depend crucially on the sophistication of the principal and on the scale of roll-out.

The twentieth century has seen the birth and the development of the doctrine of the First Amendment's free speech clause. In its current state, free speech jurisprudence is hampered by coexisting but conflicting First Amendment theories and doctrines. In this Essay, Professor Post examines these conflicts. He traces the development of two primary First Amendment theories: the theory of the marketplace of ideas, exemplified by Justices Holmes' dissenting opinion in Abrams v. United States; and the theory of democratic speech, articulated most notably by Alexander Meiklejohn. After discussing the doctrinal implications of these theories and noting that courts have not followed either theory consistently, Professor Post suggests that First amendment jurisprudence could be rendered more coherent if First Amendment theories were to be ordered according to a "lexical priority" that will illuminate what is at stake in the conflict between theories and how such conflicts may be settled.

The Community Pedestrian Safety Engagement Workshops are a community capacity building program to involve local residents in community pedestrian safety. The focus of these workshops is to engage, educate and empower residents to ensure they have the skills, knowledge and resources they need to become active in improving pedestrian safety in their neighborhood, district, city or county. This program uses pedestrian planning and community engagement curriculums as a framework for the content, and goes beyond this to tailor each workshop to the individual community needs, ensuring genuine resident engagement and continued involvement.

This paper highlights the processes and strategies used to engage community residents with local professionals in pedestrian safety workshops throughout California. Several case studies are highlighted focusing on a variety of engagement techniques from obtaining elected official’s participation, outreaching and working with existing collaboratives and groups, working with youth volunteers, Video Voice, and peer learning and sharing. All of the workshops result in group-identified pedestrian safety priorities and actions for continued resident involvement and have connected previously inactive community members (both adults and youth) with community pedestrian activists. Subsequent relationships have resulted in enhanced community pedestrian safety efforts and programs that continue long past the workshop dates.

In the United States today, most residential heating systems are single zone. This means that all rooms must be either conditioned or not, which often leads to large unoccupied areas being conditioned to satisfy comfort needs in the occupied zones. Furthermore, these systems typically have only one sensor, which is often not representative of all zones. It would be desirable to have better control, but multizone systems are expensive and invasive to install if one wants to retrofit an existing residential single zone heating system into a multizone system.

A new multizone system is currently being developed at UC Berkeley to provide an inexpensive, simple retrofit strategy. This consists of a wireless vent register control system. The new registers have been fitted with a mote (a small wireless device) that can send and receive signals in order to open and close vents in a house, allowing the system to only condition the desired zones. Motes fitted with temperature sensors are also placed in the zones and outside to provide additional temperature readings to the control system. Therefore, the house can take on properties of a multizone system by only changing the registers. The goal of the overall project is to design a simple, inexpensive system that can save energy while providing thermal comfort comparable to or better than that of a traditional single zone system.

Since smaller volumes will be conditioned at a time, the heating system can potentially reach setpoint quicker, therefore running for a shorter period of time. The new system has been tested using a 1988 house in Danville, CA. This test was to verify that the system works as expected and whether target zones reach setpoint faster. While multizone systems can conceptually allow the user to fine-tune conditioning needs, the control algorithms will be more complicated. A single zone system only needs to actuate heating, cooling, and fan modes with one setpoint at a time. With the wireless vent control, the system must track which zones need to be conditioned and choose an appropriate vent configuration, in addition to the control needs of the single zone system. To optimize this system in a real house would be prohibitively complicated and time consuming. Therefore, an optimization model has been developed to determine optimal control sequences based on setpoint and occupancy. This optimization models the actual house, using real house data such as insulation values, flow rates, and fan power. It automates the choice of optimal configuration, rather than completing thousands and thousands of runs in real time in the actual house.

The Background section of this thesis will provide an overview of existing residential heating options. Specifically, it outlines the research that has been done on the effectiveness of existing multizone control strategies. It will also describe the new multizone system being developed in the UC Berkeley Demand Response Enabling Technology group. This system provides wireless control of vent registers. A statement of the problem and objectives follows the background.

Next the Methods section provides a detailed description of the hardware and software used in the wireless multizone control system. The development of the hardware and software for this project is the subject of William Watt’s thesis, Multizone HVAC Control with Smart Vent Louvers (2007). This section discusses the initial house testing and the measurements. The Methods section also contains an overview of the optimization model developed in this work, including an explanation of the thermal calculations, logic, occupancy schedules, and weather data. The initial optimization model (and the resulting write-up) began as a final project in ER 220: Modeling Energy, Environmental, and Resource Systems. Petek Gursel and Arman Shehabi contributed to this project.

This thesis contains an updated model with enhanced thermal calculations and more detailed analysis. The Results section provides tables and figures from both the basecase (single zone control) and the multizone control runs, and also presents the sensitivity analysis.

The Discussion, Future Work, Conclusion, and References sections follow. Finally, many people have been involved in the completion of this thesis. Acknowledgements can be found at the end of the paper.

The United States maintains an artificial hierarchy amongst Native American tribes by acknowledging, or recognizing, some tribes’ inherent tribal sovereignty over others. Tribes are considered federally recognized or unrecognized not because of intrinsic differences, but rather the history of their interactions with the government. Without a federally recognized sovereign status unrecognized tribes are often landless, are denied protections from federal laws designed to aid Native people and tribal nations, are unable access to federal resources for education or health services, and are limited in their ability to practice self-determination. Unrecognized tribes and tribal members are also subject to intangible difficulties from skeptics who question cultural authenticity and suggest ethnic fraud. California has the most unrecognized tribes in the country and the most that have taken steps to pursue federal recognition through the Federal Acknowledgment Process, a system using seven criteria to acknowledge tribal sovereignty that is administered by the Office of Federal Acknowledgment within the Department of the Interior.

The Process and The People analyzes the politics and history of federal recognition in California and its connection to contemporary Native identity. This study provides critical context on the origins of federal acknowledgment and the Federal Acknowledgment Process within a broader lineage of colonial laws and policies that bear on Native American identity. Focusing explicitly on federal acknowledgment in California, it traces the settler colonial history of the state and its connection to the current crisis of federal recognition across Native California. The Process and The People also includes a case study of the San Luis Rey Band of Mission Indians, the only unrecognized tribe in San Diego County. As part of a larger movement of unrecognized tribes in California seeking recognition, the case of the San Luis Rey Band exemplifies the issues of recognition in the state while highlighting the tribe’s unique history within the broader recognition landscape. Through the experience of the San Luis Rey Band, The Process and The People contends that the tribe’s engagement with the Federal Acknowledgment Process is part of a longer history of tribal interaction with the federal government. The case illustrates to what extent tribes can use the Federal Acknowledgment Process for their own political and social purposes, how unrecognized tribes enact self-determination and tribal sovereignty, and what understandings of community identity underpin the pursuit for federal recognition.