The performance and application of high speed long life LH2 hybrid bearings for reusable rocket engine turbomachinery

Data are presented for two different experimental programs which were conducted to investigate the characteristics of a hybrid (hydrostatic/ball) bearing operating in liquid hydrogen. The same bearing design was used in both programs. Analytical predictions were made of the bearing characteristics and are compared with the experimental results when possible. The first program used a bearing tester to determine the steady state, transient, and cyclic life characteristics of the bearing over a wide range of operating conditions. The second program demonstrated the feasibility of applying hybrid bearings to an actual high speed turbopump by retrofitting and then testing an existing liquid hydrogen turbopump with the bearings

On the Contractivity of Hilbert-Schmidt distance under open system dynamics

We show that the Hilbert-Schmidt distance, unlike the trace distance, between quantum states is generally not monotonic for open quantum systems subject to Lindblad semigroup dynamics. Sufficient conditions for contractivity of the Hilbert-Schmidt norm in terms of the dissipation generators are given. Although these conditions are not necessary, simulations suggest that non-contractivity is the typical case, i.e., that systems for which the Hilbert-Schmidt distance between quantum states is monotonically decreasing form only a small set of all possible dissipative systems for N>2, in contrast to the case N=2 where the Hilbert-Schmidt distance is always monotonically decreasing.Comment: Major revision. We would particularly like to thank D Perez-Garcia for constructive feedbac

Optimized pulse sequences for suppressing unwanted transitions in quantum systems

We investigate the nature of the pulse sequence so that unwanted transitions in quantum systems can be inhibited optimally. For this purpose we show that the sequence of pulses proposed by Uhrig [Phys. Rev. Lett. \textbf{98}, 100504 (2007)] in the context of inhibition of environmental dephasing effects is optimal. We derive exact results for inhibiting the transitions and confirm the results numerically. We posit a very significant improvement by usage of the Uhrig sequence over an equidistant sequence in decoupling a quantum system from unwanted transitions. The physics of inhibition is the destructive interference between transition amplitudes before and after each pulse.Comment: 5 figure

Scalability of Shor's algorithm with a limited set of rotation gates

Typical circuit implementations of Shor's algorithm involve controlled rotation gates of magnitude $\pi/2^{2L}$ where $L$ is the binary length of the integer N to be factored. Such gates cannot be implemented exactly using existing fault-tolerant techniques. Approximating a given controlled $\pi/2^{d}$ rotation gate to within $\delta=O(1/2^{d})$ currently requires both a number of qubits and number of fault-tolerant gates that grows polynomially with $d$. In this paper we show that this additional growth in space and time complexity would severely limit the applicability of Shor's algorithm to large integers. Consequently, we study in detail the effect of using only controlled rotation gates with $d$ less than or equal to some $d_{\rm max}$. It is found that integers up to length $L_{\rm max} = O(4^{d_{\rm max}})$ can be factored without significant performance penalty implying that the cumbersome techniques of fault-tolerant computation only need to be used to create controlled rotation gates of magnitude $\pi/64$ if integers thousands of bits long are desired factored. Explicit fault-tolerant constructions of such gates are also discussed.Comment: Substantially revised version, twice as long as original. Two tables converted into one 8-part figure, new section added on the construction of arbitrary single-qubit rotations using only the fault-tolerant gate set. Substantial additional discussion and explanatory figures added throughout. (8 pages, 6 figures

Proceedings of the 23rd annual Central Plains irrigation conference

Presented at Proceedings of the 23rd annual Central Plains irrigation conference held in Burlington, Colorado on February 22-23, 2011.Includes bibliographical references

An Agenda for the Obama Administration on Gender Equality: Lessons from Abroad

President Barack Obama came into office with a wealth of good will after winning the historic 2008 presidential election to become the first African-American commander-in-chief. Among the many daunting issues we hope he will tackle is one that Abigail Adams mentioned to her husband John in 1776: remember the ladies. How should our President and his new administration affect social justice for women

Reorientando a identidade nacional em Native speaker, de Chang-rae Lee, e O sol se põe em São Paulo, de Bernardo Carvalho

Uma leitura comparativa entre os romances Native speaker (1995), do escritor norte-americano Chang-rae Lee, e O sol se põe em São Paulo (2007), de Bernardo Carvalho, permite uma reavaliação da construção das identidades minoritárias presentes nas duas megalópoles americanas de Nova York e São Paulo. Os enredos dos dois romances são marcados por uma crise de identidade vivida por um homem, descendente de imigrantes asiáticos (da Coreia num caso e do Japão no outro), que procura negociar sua identidade americana (falando em termos hemisféricos) em termos da origem e língua de sua família. Contudo, apesar das ansiedades parecidas sobre a assimilação presentes nos dois romances, ambos revelam diferenças significativas em relação às formas como os Estados Unidos e o Brasil responderam às diferenças culturais ao mesmo tempo que desafiam os mitos nacionais de inclusão e pertencer.&nbsp

A RESISTÊNCIA AO AUTORITARISMO PATRIARCAL E POLÍTICO EM ARMADILHA PARA LAMARTINE DE CARLOS & CARLOS SUSSEKIND

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Immigrant Belonging in Belgium: Laws, Localities, and Living Together

Nationalism is rising in Europe and the world. Much of it responds to massive migration, with nationalistic Europeans vocalizing their belief that immigrants do not “belong” in their countries. Many states respond to this influx of people and rising antiimmigrant sentiment by creating laws demanding immigrant “integration.” Yet a clear understanding of what defines “integration” remains elusive. So too does an understanding of how laws aimed at immigrant integration influence relationships between immigrants and local citizens, institutions, and spaces. This research addresses both of these points in Belgium, a politically and culturally fractured country that serves as a microcosm of Europe’s integration debates. This research investigates “integration” laws in Wallonia, Belgium’s francophone region, and understandings of integration and belonging as considered by: (1) workers tasked with implementing Wallonia’s integration laws, (2) migrants affected by these laws, and (3) locals comprising the “host society” into which migrants are to integrate according to the laws. Findings from interviews with integration workers show that “integration” cannot conceptually be categorized as an either/or proposition set forth by the state along a multicultural versus assimilationist ideological spectrum. Workers simultaneously incorporate elements from normative assimilationist and multicultural models to create a localized sense of integration. Actors implementing integration laws do so differently—at a localized level—based on divergent ideas of belonging and community. Each worker has his or her own notions of how things should be, or how they are on the ground, and acts accordingly. Laws may dictate one thing; workers may do another. Findings from interviews with migrants engaging with Wallonia’s legally mandated integration programs reveal that migrants’ seemingly instrumental decision to acquire legal citizenship is not devoid of emotion. Many maintain an attachment to the country’s political culture, meaning safety, personal liberty, and legal institutions, rather than the national culture. Others seek legal citizenship to secure a sense of belonging in their new state. The migrants’ emotional attachments to the state are thus real, but perhaps without the full panoply of emotions desired by nationalists. Findings from interviews with locals considered members of the “host society” provides empirical evidence contesting the idea of uniform host societies and congruity between society and state (or even substate) boundaries. Host societies are not monolithic entities and nationalist ideologies do not necessarily shape immigration, integration, and citizenship policies in any singular way; there is a process that significantly varies across national space. This variance results from fellow community members’ competing imaginaries and emotional attachments to place that may be more local in nature. Each person acts according to his or her own notions of who they are and who members of their fellow community are. So while certain ideas/societal conceptions may appear one way, everyday imaginations may be different. This contributes to an increasing literature focused on host society perceptions. And it provides a new framework for considering ordinary persons’ perspectives by engaging elements from existing frameworks addressing nationalism and identity (everyday nationhood and belonging). In sum, this research expands theoretical frameworks regarding belonging, citizenship, and identity while simultaneously providing informed perspectives to those working with immigrants and also officials crafting integration laws