Now showing items 86-105 of 375

• #### Extending the piecewise exponential estimator of the survival function ﻿

(Wichita State University. Graduate School., 2008-04-25)
We propose a new way of extending the piecewise exponential estimator (PEXE) beyond the last observation, where the original PEXE and the Kaplan-Meier estimator (KME) of the true survival function (SF) are undefined. ...
• #### Fairest edge usage and minimum expected overlap for random spanning trees ﻿

(Elsevier, 2021-05)
Random spanning trees of a graph $G$ are governed by a corresponding probability mass distribution (or "law"), $\mu$ defined on the set of all spanning trees of $G$ This paper addresses the problem of choosing $\mu$ in ...
• #### A fast local level set method for inverse gravimetry ﻿

(Global-Science Press, 2011)
We propose a fast local level set method for the inverse problem of gravimetry. The theoretical foundation for our approach is based on the following uniqueness result: if an open set D is star-shaped or x(3)-convex with ...
• #### First measurement of electron neutrino appearance in NOvA ﻿

(American Physical Society, 2016-04-13)
We report results from the first search for $\nu_\mu\to\nu_e$ transitions by the NOvA experiment. In an exposure equivalent to $2.74\times10^{20}$ protons-on-target in the upgraded NuMI beam at Fermilab, we observe 6 events ...
• #### First measurement of muon-neutrino disappearance in NOvA ﻿

(American Physical Society, 2016-03-25)
This paper reports the first measurement using the NOvA detectors of $\nu_\mu$ disappearance in a $\nu_\mu$ beam. The analysis uses a 14 kton-equivalent exposure of $2.74 \times 10^{20}$ protons-on-target from the Fermilab ...
• #### Fischer-Tropsch synthesis: Activity and selectivity of chi-Fe5C2 and circle minus-Fe3C carbides ﻿

(American Chemical Society, 2014-08-10)
Two different iron carbides, Hägg (χ-Fe5C2) and cementite (ϴ-Fe3C) for Fischer-Tropsch synthesis (FTS) was investigated. Both iron carbides were oxidized to Fe3O4 ​during FTS. Hägg carbide (χ-Fe5C2), initially exhibits ...
• #### Fischer-Tropsch synthesis: Deactivation as a function of potassium promoter loading for precipitated iron catalyst ﻿

(Springer, 2014-10)
The effect of potassium promoter loading (0, 0.5, 1.0 and 2.0 atomic ratio) on the performance of precipitated iron catalysts was investigated during Fischer-Tropsch synthesis using a continuously stirred tank reactor. ...
• #### Fischer-Tropsch synthesis: Effect of activation gas after varying Cu promoter loading over K-promoted Fe-based catalyst ﻿

The effects of activation gas and copper promoter loading on the Fischer-Tropsch synthesis performance of potassium promoted precipitated iron-based catalysts were investigated using a continuously stirred tank reactor. ...
• #### Fischer-Tropsch synthesis: Effect of ammonia in syngas on the Fischer-Tropsch synthesis performance of a precipitated iron catalyst ﻿

(Elsevier B.V., 2015-06)
The effect of ammonia in syngas on the Fischer-Tropsch synthesis (FTS) reaction over 100Fe/5.1Si/2.0Cu/3.0K catalyst was studied at 220-270 degrees C and 1.3 MPa using a 1-L slurry phase reactor. The ammonia added in syngas ...
• #### Fischer-Tropsch synthesis: Effect of CO conversion on CH4 and oxygenate selectivities over precipitated Fe-K catalysts ﻿

(Elsevier, 2018-06-25)
The explanation for CH4 selectivity for iron based Fischer-Tropsch catalysts in the low conversion region (Le., < 50%) remains elusive. In this contribution, the CO conversion effect was carefully examined over four K ...
• #### Fischer-Tropsch synthesis: Effect of Cu, Mn and Zn addition on activity and product selectivity of cobalt ferrite ﻿

(Royal Society of Chemistry, 2016)
The effect of Cu, Mn and Zn addition on cobalt ferrite was investigated for Fischer-Tropsch synthesis (FTS). Oxalate co-precipitation followed by decomposition under inert conditions was used to obtain various metal ...
• #### Fischer-Tropsch Synthesis: Effect of potassium on activity and selectivity for oxide and carbide Fe catalysts ﻿

(Springer US, 2013-11)
The effect of potassium on oxides and carbides of iron for Fischer-Tropsch synthesis (FTS) was investigated by pretreating Fe3O4 and K-promoted Fe catalysts with different gases (H-2/H2O and CO). A freshly activated sample ...
• #### Fischer-Tropsch synthesis: Effects of hydrohalic acids in syngas on a precipitated iron catalyst ﻿

(American Chemical Society, 2015-05)
The current investigation was undertaken to identify limits of hydrohalic acid (HX, X = F, Cl, Br) impurities in syngas and shed light on the mechanism of FIX poisoning of a 100 Fe/5.1 Si/2 Cu/3 K FTS catalyst under ...
• #### Fischer-Tropsch synthesis: Morphology, phase transformation, and carbon-layer growth of iron-based catalysts ﻿

(John Wiley & Sons, Inc., 2014-07)
The morphological, phase transformations and carbon-layer growth for unpromoted and K-promoted iron catalysts were investigated over time during Fischer-Tropsch synthesis. Catalysts were activated in CO for 24 h, which ...
• #### Fischer–Tropsch synthesis: Mössbauer investigation of iron containing catalysts for hydrogenation of carbon dioxide ﻿

(Elsevier, 2012-05-25)
CO2 hydrogenation was investigated with a doubly promoted (Cu, K) silica containing iron catalyst. Hägg carbide (χ-Fe5C2) is the dominant phase obtained under CO activation conditions at 543 K and 0.1 MPa and it was stable ...
• #### Fixed points and determining sets for holomorphic self-maps of a hyperbolic manifold ﻿

(University of Michigan. Dept. of Mathematics, 2007)
We study fixed point sets for holomorphic automorphisms (and endomorphisms) on complex manifolds. The main object of our interest is to determine the number and configuration of fixed points that forces an automorphism ...
• #### A Fornberg-like method for the numerical conformal mapping of bounded multiply connected domains ﻿

(Wichita State University. Graduate School, 2010-04-23)
A new Fornberg-like method is presented for computing conformal maps from the interior of the unit disk with m>1 circular holes to the interior of a smooth closed curve with m holes bounded by smooth curves. The method is ...
• #### A Fornberg-like method for the numerical conformal mapping of bounded multiply connected domains ﻿

(Wichita State University, 2009-05)
A new Fornberg-like method is presented for computing conformal maps from the interior of the unit disk with m-1 circular holes to the interior of a smooth closed curve with m-1 holes bounded by smooth curves. The method ...
• #### Forty two problems of first degree from Diophantus’ Arithmetica ﻿

(Wichita State University, 2010-12)
This work brings to the audience Diophantus' problems of first degree in a literal word for word English translation from Ver Eecke's French translation of Arithmetica. In addition, these problems are accompanied by ...
• #### Forty-fold speedup of NV- center magnetometry with sequential Bayesian experiment design ﻿

(IEEE, 2021-05-01)
In magnetometry using quantum defects in diamond (NV - centers), we demonstrate forty-fold speedup with sequential Bayesian experiment design as compared with conventional NV-magnetometry using frequency-swept measurements.