Mass-transport resistances of acid and alkaline ionomer layers: A microelectrode study part 1 - Microelectrode development

The use of microelectrodes to study localized mass-transport phenomena in fuel-cell catalyst layers is an increasingly valuable tool. However, existing microelectrode cells have been used in static, equilibrated environment modes with poorly controlled interfaces. In this work, we present a microelectrode cell design that expands the experimental space addressable by microelectrodes to include mechanical pressure, gas flow and ionomer medium, and experimental throughput. The feasibility of the design is examined for fuel-cell reactions, with oxygen reduction currents independent of mechanical pressure and gas flowrate. Finally, cell equilibration time and IR drop across the electrolyte are estimated. The new cell design is robust and provides a consistent base from which to perform more complicated studies examining mass-transport properties of ionomers and/or the electrochemical reaction kinetics of hydrogen oxidation and oxygen reduction

Comparison of the effect of locking vs standard screws on the mechanical properties of bone-plate constructs in a comminuted diaphyseal fracture model

The purpose of this study was to compare the mechanical properties of bone-plate constructs with locking compression plates (LCP) used either with standard screws or with locking screws on an experimental model of comminuted fracture

Permeation of CO2 and N2 through glassy poly(dimethyl phenylene) oxide under steady- and presteady-state conditions

Glassy polymers are often used for gas separations because of their high selectivity. Although the dual-mode permeation model correctly fits their sorption and permeation isotherms, its physical interpretation is disputed, and it does not describe permeation far from steady state, a condition expected when separations involve intermittent renewable energy sources. To develop a more comprehensive permeation model, we combine experiment, molecular dynamics, and multiscale reaction–diffusion modeling to characterize the time-dependent permeation of N2 and CO2 through a glassy poly(dimethyl phenylene oxide) membrane, a model system. Simulations of experimental time-dependent permeation data for both gases in the presteady-state and steady-state regimes show that both single- and dual-mode reaction–diffusion models reproduce the experimental observations, and that sorbed gas concentrations lag the external pressure rise. The results point to environment-sensitive diffusion coefficients as a vital characteristic of transport in glassy polymers

An Investigation on the Rate of Crime in Sokoto State Using Principal Component Analysis

Principal component analysis is a data analysis tools that is used to reduce the dimensionality of a large number of interrelated variables, while retaining as much of the information as possible. In this paper, PCA technique has been applied to know the number of principal components to be retained on the seven variables obtained from Criminal Investigation Department Sokoto State Police Headquarters Sokoto. Data analysis was carried out using NCSS and GESS 2007 Software. From the results, three Principal components have been retained using the Scree plot and Loading plot indicating that correlation exist between crimes against persons and crime against properties

Optimized intermolecular potential for nitriles based on Anisotropic United Atoms model

An extension of the Anisotropic United Atoms intermolecular potential model is proposed for nitriles. The electrostatic part of the intermolecular potential is calculated using atomic charges obtained by a simple Mulliken population analysis. The repulsion-dispersion interaction parameters for methyl and methylene groups are taken from transferable AUA4 literature parameters [Ungerer et al., J. Chem. Phys., 2000, 112, 5499]. Non-bonding Lennard-Jones intermolecular potential parameters are regressed for the carbon and nitrogen atoms of the nitrile group (–C≡N) from experimental vapor-liquid equilibrium data of acetonitrile. Gibbs Ensemble Monte Carlo simulations and experimental data agreement is very good for acetonitrile, and better than previous molecular potential proposed by Hloucha et al. [J. Chem. Phys., 2000, 113, 5401]. The transferability of the resulting potential is then successfully tested, without any further readjustment, to predict vapor-liquid phase equilibrium of propionitrile and n-butyronitrile

Interval Selection in the Streaming Model

A set of intervals is independent when the intervals are pairwise disjoint. In the interval selection problem we are given a set $\mathbb{I}$ of intervals and we want to find an independent subset of intervals of largest cardinality. Let $\alpha(\mathbb{I})$ denote the cardinality of an optimal solution. We discuss the estimation of $\alpha(\mathbb{I})$ in the streaming model, where we only have one-time, sequential access to the input intervals, the endpoints of the intervals lie in $\{1,...,n \}$, and the amount of the memory is constrained. For intervals of different sizes, we provide an algorithm in the data stream model that computes an estimate $\hat\alpha$ of $\alpha(\mathbb{I})$ that, with probability at least $2/3$, satisfies $\tfrac 12(1-\varepsilon) \alpha(\mathbb{I}) \le \hat\alpha \le \alpha(\mathbb{I})$. For same-length intervals, we provide another algorithm in the data stream model that computes an estimate $\hat\alpha$ of $\alpha(\mathbb{I})$ that, with probability at least $2/3$, satisfies $\tfrac 23(1-\varepsilon) \alpha(\mathbb{I}) \le \hat\alpha \le \alpha(\mathbb{I})$. The space used by our algorithms is bounded by a polynomial in $\varepsilon^{-1}$ and $\log n$. We also show that no better estimations can be achieved using $o(n)$ bits of storage. We also develop new, approximate solutions to the interval selection problem, where we want to report a feasible solution, that use $O(\alpha(\mathbb{I}))$ space. Our algorithms for the interval selection problem match the optimal results by Emek, Halld{\'o}rsson and Ros{\'e}n [Space-Constrained Interval Selection, ICALP 2012], but are much simpler.Comment: Minor correction

Causality Analysis of the Impact of Foreign Direct Investment on GDP in Nigeria

This study used a Cointegration VAR model to study the Contemporaneous Long – run dynamics of the impact of foreign direct Investment (FDI) on Growth Domestics Products (GDP) with other four macroeconomic variables in the Nigerian Economy for the period of January 1970 to December 2004. The Unit Root Test suggests that all the variables are integrated of order 1. The VAR (3) model were appropriately Identified using AIC information criteria and the VECM (2) model with cointegration relation of exactly one .The study further investigate the causal relationship using the Granger Causality analysis of VECM which indicates a uni–directional causal relationship between GDP and FPI at 5% as in inline with other studies of Basu et al.(2003). The results of Granger Causality Analysis also show that some of the variables are Granger Causal of one another, at 5% level of significance. Having established the fact that foreign direct investment has positive impact on growth domestic product, government should strategize policies that would enhance foreign direct investment in Nigeria

Do neighbouring countries encourage the demand of international business tourism?

This paper aims at determining the factors that influence the growth of international business tourism and understanding whether the demand growth of business tourism spreads across neighbouring countries. For the development of the empirical research, data has been collected from a sample of 136 countries worldwide, and spatial econometric techniques have been used. Evidence that supports the idea that the main factors related to the increase in incomes of business tourism are the private investment on tourism assets, the leisure tourism and the trade openness in relation to the outside world is presented. This study also reveals that the demand of business tourism in a country is not contagious, that is, the demand varies neither with the demand of its neighbours nor with their exogenous characteristics. The results have important implications for the choice of tourism policy goals at national levels and the corresponding policy instruments.8316-FD77-85EB | Pedro Miguel Fonseca Moreira de CarvalhoN/