scholarly journals Case studies of the radical cation reactivity in meso-aryl and octaethyl porphyrins

2020 ◽  
Vol 24 (05n07) ◽  
pp. 860-868
Author(s):  
R. Lamare ◽  
L. Ruhlmann ◽  
R. Ruppert ◽  
J. Weiss
Keyword(s):  
Case Studies ◽  
Radical Cation ◽  
Access Route ◽  
Cationic Species ◽  
Non Linear ◽  
Porphyrin Dimers

The reactivity of porphyrin radical cationic species derived from octaethyl porphyrin (OEP) or meso-aryl porphyrins with nucleophiles, envisioned as an access route to elaborate porphyrin dimers, has been studied and optimized in the case of OEP. Standardized conditions have been applied to various spacers to show that the success of the reaction is mostly nucleophile dependent and that the method has little chances to yield non-linear bis-porphyrins.

Non-Linear Corrosion Growth: A More Appropriate and Accurate Model for Predicting Corrosion Growth Rate

2016 ◽  
Author(s):  
M. Al-Amin ◽  
S. Kariyawasam ◽  
S. Zhang ◽  
W. Zhou
Keyword(s):  
Growth Rate ◽  
Case Studies ◽  
Growth Model ◽  
Measurement Errors ◽  
Linear Growth ◽  
Management Program ◽  
Linear Growth Rate ◽  
Metal Loss ◽  
Contributing Factors ◽  
Non Linear

External metal-loss corrosion is one of the major contributing factors for pipeline failures in North America. Corrosion growth rate plays a crucial role in managing corrosion hazard for gas and liquid pipelines. Quantifying the growth of corrosion over time is critically important for the risk and reliability analysis of pipelines, planning for corrosion mitigation and repair, and determination of time intervals for corrosion inspections. Conservatism in predicting the growth rate has significant engineering implication as non-conservatism can lead to critical anomalies being missed by mitigation actions and may cause pipeline failure; whereas, over conservatism can lead to unnecessary inspections and anomaly mitigations that may result in significant unnecessary cost to pipeline operators. As more and more pipelines are now being inspected by in-line inspection (ILI) tools on a regular basis, the ILI data from multiple inspections provide valuable information about the growth of corrosion anomalies on the pipeline. Although the application of linear growth rate calculated by comparing depths from two successive ILI is a common practice in the pipeline industry, research has shown that the growth of corrosion anomaly is non-linear and anomaly-specific. The authors of this paper have previously developed anomaly-specific non-linear corrosion growth model based on multiple ILI data. The objectives of this paper are to demonstrate the appropriateness of anomaly-specific non-linear corrosion growth model, and to illustrate the advantages of using non-linear corrosion growth model in the integrity management program. Two case studies were performed to illustrate the application of non-linear growth model by incorporating the measurement errors associated with the ILI tools, which include both the bias (constant and non-constant) and random scattering error. The findings of these case studies are presented in this paper.

A Generalized Contact Model for Nonlinear Dynamic Analysis of Floating Offshore Systems

2006 ◽  
Author(s):  
Danilo Machado Lawinscky da Silva ◽  
Fabri´cio Nogueira Correˆa ◽  
Breno Pinheiro Jacob
Keyword(s):  
Data Structure ◽  
Dynamic Analysis ◽  
Case Studies ◽  
Nonlinear Dynamic ◽  
Nonlinear Dynamic Analysis ◽  
Contact Model ◽  
Non Linear ◽  
Contact Models ◽  
Lateral Friction

The objective of this work is to present the implementation of a contact model that represents, during a nonlinear dynamic analysis of floating offshore systems, the contact of lines with the platform, as well as the contact involving different lines and, eventually, involving two different platforms in the same model. Traditional contact models consider for instance a generalized scalar element, consisting of two nodes linked by a non-linear gap spring. In this work, the contact model is geometrically defined by volumes that cannot interpenetrate. A penetration stiffness can be defined for each volume; lateral friction can also be considered by this model. An appropriate data structure is used to define the volumes and guarantee the efficiency of the algorithm by an optimized search. The application of the presented contact model is demonstrated by case studies of actual applications for offshore systems: pipelines in S-Lay installation operations, where the contact is complex, specified only in some points of the ramp and stinger; offloading floating hoses that may collide with the hull of the ship, and catlines in lift operations.

As It Was in the Beginning

2016 ◽  
Author(s):  
David G. Bromley
Keyword(s):  
Public Sphere ◽  
Case Studies ◽  
First Generation ◽  
Developmental Trajectories ◽  
Basic Premise ◽  
New Religions ◽  
Non Linear ◽  
Initial Discovery ◽  
The Rich ◽  
In The Beginning

The study of new religions in the making (NRMs) is particularly valuable to the study of religion as it offers a window into the process by which religious organizations develop. This chapter draws on insights in the rich set of case studies of NRMs and on the organizational startup literature to fashion a prolegomenon to a theory of the first generation development of NRMs. The basic premise is that all new organizations encounter similar developmental challenges. The objective is to identify factors that influence alternative levels of development and developmental trajectories during the first generation. The process is described in terms of three non-linear, sequential developmental moments: initial discovery, public sphere entry, and expansion/consolidation.

scholarly journals Numerical approximation of nonlinear chromatographic models considering Bi-Langmuir isotherm

2020 ◽  
pp. 298-298
Author(s):  
Ambreen Khan ◽  
Sadia Perveen ◽  
Zarmeena Shaheen ◽  
Shamsul Qamar
Keyword(s):  
Case Studies ◽  
Approximate Solutions ◽  
Critical Parameters ◽  
Finite Volume Scheme ◽  
Test Case ◽  
Process Performance ◽  
Lumped Model ◽  
Non Linear ◽  
Model Equations ◽  
Non Linear System

In this research article, two standard models of liquid chromatograophy, namely the dispersive equilibrium model (DEM) and the kinetic lumped model (KLM) are approximated numerically. We studied the transport of multi components in a single column of chromatography considering non linear adsorption thermodynamics. The models are analyzed for standard Bi-Langmuir and generalized Bi-Langmuir types adsorption equilibrium isotherms using Danckwert (Robin) boundary conditions. Mathematically, the model equations form a non linear system of partial differential equations accounting for the phenomena of advection and diffusion, paired with an algebraic equation or a differential equation for adsorption isotherm. An extended semi-discrete high-resolution finite volume scheme is employed to obtain the approximate solutions of the governing model equations. The method has second to third order accuracy. Several test case studies are conducted to examine the influence of various critical parameters on the process performance. The contemplated case studies incorporate the elution process of liquid chromatography with an increasing number of components. In particular, single component, two component and three component mixtures are considered for the assessment of process performance. The formulated numerical algorithm provide an efficacious mechanism for investigating the retention behavior and the influence of mass transfer kinetics on the shapes of elution profiles.

Recent Developments in F.E. Analysis of FRP Reinforced Masonry Vaults: Case Studies in Italy

2014 ◽  
Vol 624 ◽  
pp. 389-396 ◽  
Author(s):  
Gabriele Milani ◽  
Antonio Tralli
Keyword(s):  
Case Studies ◽  
Limit Analysis ◽  
Piecewise Constant Function ◽  
Emilia Earthquake ◽  
Structural Deterioration ◽  
First Case ◽  
Reinforced Masonry ◽  
Non Linear ◽  
Masonry Vaults ◽  
2012 Emilia Earthquake

Aim of the present paper is the analysis of a series of existing masonry cross vaults exhibiting meaningful structural deterioration and diffused crack patterns, by means of an advanced non-linear and limit analysis software. The approach utilized is a non-standard and non-commercial one and bases both for the non-linear and limit analysis procedure on a FE discretization of the domain by means of rigid infinitely resistant wedges, where all the non-linearity is concentrated on interfaces between adjoining elements [1-3]. When dealing with the non-linear code, a sequential quadratic programming scheme is used at each iteration in order to deal with the deterioration of mechanical properties of interfaces, provided that the actual non-linear behavior is approximated by means of a linear piecewise constant function. Some real case studies of historic buildings in Italy are discussed. The first case study is represented by the structural analysis of a series of existing masonry cross vaults constituting the roof system of the ground floor of the former Caserma Lorenzini (ex Convent of S. Lorenzo) in Lucca, Italy, at the moment subjected to a wide restoration intervention within the so called Piuss project. The second is represented by the cross vaults of a 12th century masonry sighting tower damaged by the 20th may 2012 Emilia earthquake. This medieval tower, called Torre Fornasini, is located in the municipality of Poggio Renatico, about 10 km from Ferrara.

scholarly journals International students’ linguistic transitions into disciplinary studies: a rhizomatic perspective

2021 ◽  
Author(s):  
Doris Dippold ◽  
Marion Heron ◽  
Karen Gravett
Keyword(s):  
Higher Education ◽  
International Students ◽  
Case Studies ◽  
Number Of Factors ◽  
Non Linear ◽  
And Performance ◽  
Uk Higher Education ◽  
Developing Strategies ◽  
Speaking Skills

AbstractThis paper offers a reconceptualisation of international students’ transitions into and through UK higher education. We present two case studies of students which explore their transitions in terms of their academic speaking skills from pre-sessional courses into their disciplinary studies. Students describe how the development of their confidence and performance in academic speaking was contingent on a number of factors and micro-moments, and how this progress into and within disciplinary studies often involved regression and discomfort. Nevertheless, they also talked of developing strategies to overcome challenges and the resultant learning. We argue that transitions to disciplinary studies in terms of academic speaking can be more helpfully understood as non-linear, fluid and rhizomatic. This study offers valuable insights for individuals and institutions to move away from a fixed student lifecycle perspective to consider instead how reciprocal, embedded and on-going support for international students may better reflect students’ experiences.

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