Chemical origin of the Venusian clouds Final report

Chemical analysis of cloud components in upper atmosphere of Venu

Utility operational experience on the NASA/DOE MOD-0A 200-kW wind turbine

The Mod-0A 200 wind turbine was designed and fabricated as part of the Federal Wind Energy Program. Early wind turbine operation and performance data were obtained while gaining initial experience in the operation of large, horizontal axis wind turbines in typical utility environments. The Mod-0A wind turbine was turned over to the Town of Clayton Light and Water Plant, Clayton, NM, for utility operation and on December 31, 1978, the machine had completed ten months of utility operation. The machine is described and the recent operational experience at Clayton, NMis documented

Chemical origin of the Venusian clouds Interim report, 1 Oct. 1966 - 30 Jan. 1967

Chemical reactions between solar hydrogen and carbon monoxide in Venus atmospher

Green's Relations in Finite Transformation Semigroups

We consider the complexity of Green's relations when the semigroup is given by transformations on a finite set. Green's relations can be defined by reachability in the (right/left/two-sided) Cayley graph. The equivalence classes then correspond to the strongly connected components. It is not difficult to show that, in the worst case, the number of equivalence classes is in the same order of magnitude as the number of elements. Another important parameter is the maximal length of a chain of components. Our main contribution is an exponential lower bound for this parameter. There is a simple construction for an arbitrary set of generators. However, the proof for constant alphabet is rather involved. Our results also apply to automata and their syntactic semigroups.Comment: Full version of a paper submitted to CSR 2017 on 2016-12-1

Variational quantum Monte Carlo simulations with tensor-network states

We show that the formalism of tensor-network states, such as the matrix product states (MPS), can be used as a basis for variational quantum Monte Carlo simulations. Using a stochastic optimization method, we demonstrate the potential of this approach by explicit MPS calculations for the transverse Ising chain with up to N=256 spins at criticality, using periodic boundary conditions and D*D matrices with D up to 48. The computational cost of our scheme formally scales as ND^3, whereas standard MPS approaches and the related density matrix renromalization group method scale as ND^5 and ND^6, respectively, for periodic systems.Comment: 4+ pages, 2 figures. v2: improved data, comparisons with exact results, to appear in Phys Rev Let

Revisiting and revitalizing political ecology in the American West

Political ecology, initially conceived to better understand the power relations implicit in management and distribution of natural resources in the developing world, came “home” to the American West in the 1990s and 2000s. This groundswell of research did much to problematize socio-environmental conflicts in the region, long typified by tensions over land and resources, identity and belonging, autonomy and authority. Since first touching down in the West, however, the “big tent” of political ecology has only grown bigger, incorporating new perspectives, epistemologies, and ontologies. At the same time, the nexus of environment and society is perhaps even more salient today, amid a regional conjuncture of populist revolt, climate change, and rapid political economic transformation. Here we reflect on three longstanding regional concerns – energy development, wolf reintroduction, and participatory governance – leveraging the pluralism of contemporary political ecology to better understand their contemporary incarnations. In so doing, we highlight the need to bring together insights from both “traditional” approaches and newer directions to better understand and engage contemporary challenges, with their heightened stakes and complexity. Such an approach demonstrates what we might learn about global processes in this place, as well as what insights regional praxis (often woefully provincial) might gain from elsewhere – new ways of seeing and doing political ecology. Our goal is to generate discussion among and between political ecologists and regional critical scholars, initiating new collaborative engagements that might serve the next wave of political ecology in the 21st century American West