Results 121 to 130 of about 20,142 (264)

Compact Manifolds With Unbounded Nilpotent Fundamental Groups and Positive Ricci Curvature

open access: yesCommunications on Pure and Applied Mathematics, EarlyView.
ABSTRACT It follows from the work of Kapovitch and Wilking that a closed manifold with nonnegative Ricci curvature has a uniformly almost nilpotent fundamental group. Leftover questions and conjectures, have asked if in this context the fundamental group is actually uniformly almost abelian. The main goal of this work is to construct examples (Mk9,gk)$(
Elia Bruè, Aaron Naber, Daniele Semola
wiley   +1 more source

Colour by Numbers: Solving Algebraic Equations Without Algebra

open access: yesSpreadsheets in Education, 2005
A series of Excel models is described. They allow solution of f(x) = 0 by examining change of sign of function values. The function is graphed and change of sign easily detected by a change of colour. Prominent Excel features used are Names, Chart Wizard
Stephen J. Sugden
doaj  

Photometric Diagnostic of the Sheath Dynamics and Electron Density Trends in Single and Dual Frequency CCRF Argon Plasmas

open access: yesContributions to Plasma Physics, EarlyView.
ABSTRACT A methodological study is presented on a noninvasive photometric diagnostic for determining trends in electron density and sheath dynamics in single (1f) and a dual (2f) radio frequency capacitively coupled (CCRF) argon plasmas. The 1f discharges are operated at 13.56 and 27.12 MHz, respectively, while the 2f discharge is driven by both ...
Daniel Zuhayra   +3 more
wiley   +1 more source

OpenFOAM iterative methods efficiency analysis for linear systems solving

open access: yesТруды Института системного программирования РАН, 2018
Significant part of the computational work in numerical simulations of technical systems, physical phenomena and technological processes is solving of linear algebraic equations systems arising from the discretization of the corresponding differential or
I. K. Marchevsky, V. V. Puzikova
doaj  

Kinetic Contribution to the Arbitrary Order Odd Frequency Moments of the Dynamic Structure Factor

open access: yesContributions to Plasma Physics, EarlyView.
ABSTRACT An exact expression is derived for the kinetic contribution to the odd (arbitrary order) frequency moments of the dynamic structure factor via a finite summation that features averages of even (all lower orders) powers of the momentum over the exact momentum distribution.
Panagiotis Tolias   +2 more
wiley   +1 more source

Review and prospects of shear test of bolted rock joints

open access: yesDeep Underground Science and Engineering, EarlyView.
The laboratory shear test equipment, test method, and numerical simulation of bolted rock joints were summarized. The shortcomings and limitations of the current research were analyzed, and the research prospects were proposed. Abstract Rock bolting is a critical approach in geotechnical engineering for supporting weak rocks.
Shulin Ren   +4 more
wiley   +1 more source

Latitudinal effect on the structure of snake–prey interaction networks is mediated by snake species richness

open access: yesEcography, EarlyView.
Despite the growing number of studies on trophic networks in recent decades, there are still important gaps in our understanding of how these networks are structured across broad environmental gradients. These gaps are even greater in some groups of terrestrial vertebrates, such as snakes, requiring a cohesive synthesis of their broader trophic ...
Daniela Pinto‐Coelho   +4 more
wiley   +1 more source

Influence of Structural and Environmental Parameters on Solar Air Collector Performance

open access: yesEnergy Science &Engineering, EarlyView.
Increasing air gap depth and mass flow rate significantly enhances the thermal performance of solar air collectors, with optimal performance achieved at an 8.5 cm air gap and 0.01318 kg/s mass flow rate. Air gap depth is identified as the dominant factor influencing system efficiency.
Quankun Zhu   +2 more
wiley   +1 more source

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