Now showing items 101-120 of 432

• #### Estimating cumulative incidence functions when the life distributions are constrained ﻿

In competing risks studies, the Kaplan-Meier estimators of the distribution functions (DFs) of lifetimes and the corresponding estimators of cumulative incidence functions (CIFs) are used widely when no prior information ...
• #### Estimation of a star-shaped distribution function ﻿

(Taylor & Francis LTD, 2017)
A life distribution function (DF) F is said to be star-shaped if F(x)/x is nondecreasing on its support. This generalises the model of a convex DF, even allowing for jumps. The nonparametric maximum likelihood estimation ...
• #### Estimation of distributions with the new better than used in expectation property ﻿

(Elsevier, 2013-05)
A lifetime X with survival function S, mean residual life function (MRL) M, and finite mean μ is said to be new better than used in expectation (NBUE) if M(t)≤μ for all t≥0. We propose a new estimator for S, based on a ...
• #### Examples of discontinuity for the variational solution of the minimal surface equation with Dirichlet data on a domain with a nonconvex corner and locally negative mean curvature ﻿

(Wichita State University, 2013-12)
The purpose of this thesis is to investigate the role of smoothness, specifically the smoothness of the boundary ∂Ω, in the behavior of the variational solution f on a domain Ω to the Dirichlet problem for the Minimal ...
• #### The existence of Morse-Smale diffeomorphisms in the family of Hénon maps ﻿

(Wichita State University, 2009-05)
We consider Hénon maps on ℝ² of the form fa,c(x,y)=(y,y2+c+ax) with real parameters (a, c). Due to the work of S. Hayes and C. Wolf [8], we provide a detailed investigation of the parameters 0 < a < 1 and c = 0. For each ...
• #### Experimental pairwise entanglement estimation for an N-qubit system: a machine learning approach for programming quantum hardware ﻿

(Springer, 2020-11-03)
Designing and implementing algorithms for medium- and large-scale quantum computers is not easy. In the previous work, we have suggested, and developed, the idea of using machine learning techniques to train a quantum ...
• #### 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 ...