Voltage dip immunity aspects of power-electronic equipment : recommendations from CIGRE/CIRED/UIE JWG C4.110

This paper presents some of the results from an international working group on voltage-dip immunity. The working group has made a number of recommendations to reduce the adverse impact of voltage dips. Specific recommendations to researchers and manufacturers of powerelectronic equipment are considering all voltage dip characteristics early in the design of equipment; characterize performance of equipment by means of voltage-dip immunity curves; and made equipment with different immunity available

Miniature photonic-crystal hydrophone optimized for ocean acoustics

This work reports on an optical hydrophone that is insensitive to hydrostatic pressure, yet capable of measuring acoustic pressures as low as the background noise in the ocean in a frequency range of 1 Hz to 100 kHz. The miniature hydrophone consists of a Fabry-Perot interferometer made of a photonic-crystal reflector interrogated with a single-mode fiber, and is compatible with existing fiber-optic technologies. Three sensors with different acoustic power ranges placed within a sub-wavelength sized hydrophone head allow a high dynamic range in the excess of 160 dB with a low harmonic distortion of better than -30 dB. A method for suppressing cross coupling between sensors in the same hydrophone head is also proposed. A prototype was fabricated, assembled, and tested. The sensitivity was measured from 100 Hz to 100 kHz, demonstrating a minimum detectable pressure down to 12 {\mu}Pa (1-Hz noise bandwidth), a flatband wider than 10 kHz, and very low distortion

Structures and Fragmentations of Small Silicon Oxide Clusters by ab Initio Calculations

The structures, energies, and fragmentation stabilities of silicon oxide clusters SimOn, with m = 1−5, n = 1, 2m + 1, are studied systematically by ab initio calculations. New structures for nine clusters are found to be energetically more favorable than previously proposed structures. Using the ground state structures and energies obtained from our calculations, we have also studied fragmentation pathways and dissociation energies of the clusters. Our computational results show that the dissociation energy is strongly correlated with the O/Si ratio. Oxygen-rich clusters tend to have larger dissociation energies, as well as larger HOMO−LUMO gaps. Our calculations also show that SiO is the most abundant species in the fragmentation products

Cadherin-26 (CDH26) regulates airway epithelial cell cytoskeletal structure and polarity.

Polarization of the airway epithelial cells (AECs) in the airway lumen is critical to the proper function of the mucociliary escalator and maintenance of lung health, but the cellular requirements for polarization of AECs are poorly understood. Using human AECs and cell lines, we demonstrate that cadherin-26 (CDH26) is abundantly expressed in differentiated AECs, localizes to the cell apices near ciliary membranes, and has functional cadherin domains with homotypic binding. We find a unique and non-redundant role for CDH26, previously uncharacterized in AECs, in regulation of cell-cell contact and cell integrity through maintaining cytoskeletal structures. Overexpression of CDH26 in cells with a fibroblastoid phenotype increases contact inhibition and promotes monolayer formation and cortical actin structures. CDH26 expression is also important for localization of planar cell polarity proteins. Knockdown of CDH26 in AECs results in loss of cortical actin and disruption of CRB3 and other proteins associated with apical polarity. Together, our findings uncover previously unrecognized functions for CDH26 in the maintenance of actin cytoskeleton and apicobasal polarity of AECs

Convex domains of Finsler and Riemannian manifolds

A detailed study of the notions of convexity for a hypersurface in a Finsler manifold is carried out. In particular, the infinitesimal and local notions of convexity are shown to be equivalent. Our approach differs from Bishop's one in his classical result (Bishop, Indiana Univ Math J 24:169-172, 1974) for the Riemannian case. Ours not only can be extended to the Finsler setting but it also reduces the typical requirements of differentiability for the metric and it yields consequences on the multiplicity of connecting geodesics in the convex domain defined by the hypersurface.Comment: 22 pages, AMSLaTex. Typos corrected, references update

Non-exponential London penetration depth in Ba1−_{1-}Kx_{x}Fe2_{2}As2_{2} single crystals

We have studied the in- and out-of-plane magnetic penetration depths in the hole- doped iron based superconductor Ba$_{1-x}$K$_{x}$Fe$_{2}$As$_{2}$ ($T_{c}\approx$ 30K). The study was performed on single crystals grown from different fluxes and we find that the results are nearly the same. The in-plane London penetration depth $\lambda_{ab}$ does not show exponential saturation at low temperature, as would be expected from a fully gapped superconductor. Instead, $\lambda_{ab}(T)$ shows a power-law behavior, $\lambda\propto T^{n}$ ($n\approx 2$), down to $T\approx 0.02 T_{c}$, similar to the electron doped Ba(Fe$_{1-x}$Co$_{x}$)$_{2}$As$_{2}$. The penetration depth anisotropy $\gamma_{\lambda}=\lambda_{c}(T)/\lambda_{ab}(T)$ increases upon cooling, opposite to the trend observed in the anisotropy of the upper critical field, $\gamma_{\xi}=H_{c2}^{\perp c}(0)/H_{c2}^{\parallel c}(0)$. These are universal characteristics of both the electron and hole doped 122 systems, suggesting unconventional superconductivity. The behavior of the in-plane superfluid density $\rho_{ab}(T)$ is discussed in light of existing theoretical models proposed for the iron pnictides superconductors

Simplifying Algebra in Feynman Graphs, Part III: Massive Vectors

A T-dualized selfdual inspired formulation of massive vector fields coupled to arbitrary matter is generated; subsequently its perturbative series modeling a spontaneously broken gauge theory is analyzed. The new Feynman rules and external line factors are chirally minimized in the sense that only one type of spin index occurs in the rules. Several processes are examined in detail and the cross-sections formulated in this approach. A double line formulation of the Lorentz algebra for Feynman diagrams is produced in this formalism, similar to color ordering, which follows from a spin ordering of the Feynman rules. The new double line formalism leads to further minimization of gauge invariant scattering in perturbation theory. The dualized electroweak model is also generated.Comment: 39 pages, LaTeX, 8 figure

The soil and plant biogeochemistry sampling design for The National Ecological Observatory Network

Human impacts on biogeochemical cycles are evident around the world, from changes to forest structure and function due to atmospheric deposition, to eutrophication of surface waters from agricultural effluent, and increasing concentrations of carbon dioxide (CO2) in the atmosphere. The National Ecological Observatory Network (NEON) will contribute to understanding human effects on biogeochemical cycles from local to continental scales. The broad NEON biogeochemistry measurement design focuses on measuring atmospheric deposition of reactive mineral compounds and CO2 fluxes, ecosystem carbon (C) and nutrient stocks, and surface water chemistry across 20 eco‐climatic domains within the United States for 30 yr. Herein, we present the rationale and plan for the ground‐based measurements of C and nutrients in soils and plants based on overarching or “high‐level” requirements agreed upon by the National Science Foundation and NEON. The resulting design incorporates early recommendations by expert review teams, as well as recent input from the larger natural sciences community that went into the formation and interpretation of the requirements, respectively. NEON\u27s efforts will focus on a suite of data streams that will enable end‐users to study and predict changes to biogeochemical cycling and transfers within and across air, land, and water systems at regional to continental scales. At each NEON site, there will be an initial, one‐time effort to survey soil properties to 1 m (including soil texture, bulk density, pH, baseline chemistry) and vegetation community structure and diversity. A sampling program will follow, focused on capturing long‐term trends in soil C, nitrogen (N), and sulfur stocks, isotopic composition (of C and N), soil N transformation rates, phosphorus pools, and plant tissue chemistry and isotopic composition (of C and N). To this end, NEON will conduct extensive measurements of soils and plants within stratified random plots distributed across each site. The resulting data will be a new resource for members of the scientific community interested in addressing questions about long‐term changes in continental‐scale biogeochemical cycles, and is predicted to inspire further process‐based research

Next-to-leading order QCD corrections to one hadron-production in polarized pp collisions at RHIC

We calculate the next-to-leading order QCD corrections to the spin-dependent cross section for single-inclusive hadron production in hadronic collisions. This process will be soon studied experimentally at RHIC, providing a tool to unveil the polarized gluon distribution $\Delta g$. We observe a considerably improvement in the perturbative stability for both unpolarized and polarized cross sections. The NLO corrections are found to be non-trivial, resulting in a reduction of the asymmetry.Comment: 8 pages, RevTeX4, 9 figures include