Band Electronic Structure of One- and Two-Dimensional Pentacene Molecular Crystals

We report EHT calculations of the band electronic structure of substituted pentacene derivatives and the polymorphs of the parent compound. The results show that there are wide disparities among the bandwidths and electronic dimensionalities of these compounds. The parent pentacene polymorphs are 2-dimensional in their band electronic structure with moderate dispersions; the bandwidths in the 14.1 Å d-spacing polymorph are noticeably larger than for the 14.5 Å d-spacing polymorph, reported by Campbell. Whereas the parent pentacene polymorphs adopt the well-known herringbone packing, the new, substituted pentacenes are noticeably different in their solid state structures and this is reflected in the band electronic structures. TMS adopts a highly 1-dimensional structure that leads to a large bandwidth along the stacking direction; TIPS also adopts a stacked structure, but because the molecules are laterally interleaved in the fashion of bricks in a wall, this compound is strongly 2-dimensional.

Hill's Equation with Random Forcing Parameters: Determination of Growth Rates through Random Matrices

This paper derives expressions for the growth rates for the random 2 x 2 matrices that result from solutions to the random Hill's equation. The parameters that appear in Hill's equation include the forcing strength and oscillation frequency. The development of the solutions to this periodic differential equation can be described by a discrete map, where the matrix elements are given by the principal solutions for each cycle. Variations in the forcing strength and oscillation frequency lead to matrix elements that vary from cycle to cycle. This paper presents an analysis of the growth rates including cases where all of the cycles are highly unstable, where some cycles are near the stability border, and where the map would be stable in the absence of fluctuations. For all of these regimes, we provide expressions for the growth rates of the matrices that describe the solutions.Comment: 22 pages, 3 figure

Calibration of Smearing and Cooling Algorithms in SU(3)-Color Gauge Theory

The action and topological charge are used to determine the relative rates of standard cooling and smearing algorithms in pure SU(3)-color gauge theory. We consider representative gauge field configurations on $16^3\times 32$ lattices at $\beta=5.70$ and $24^3\times 36$ lattices at $\beta=6.00$. We find the relative rate of variation in the action and topological charge under various algorithms may be succinctly described in terms of simple formulae. The results are in accord with recent suggestions from fat-link perturbation theory.Comment: RevTeX, 25 pages, 22 figures, full resolution jpeg version of Fig. 22 can be obtained from http://www.physics.adelaide.edu.au/cssm/papers_etc/SmearingComp.jp

Enhancing properties of iron and manganese ores as oxygen carriers for chemical looping processes by dry impregnation

The use of naturally occurring ores as oxygen carriers in CLC processes is attractive because of their relative abundance and low cost. Unfortunately, they typically exhibit lower reactivity and lack the mechanical robustness required, when compared to synthetically produced carriers. Impregnation is a suitable method for enhancing both the reactivity and durability of natural ores when used as oxygen carriers for CLC systems. This investigation uses impregnation to improve the chemical and mechanical properties of a Brazilian manganese ore and a Canadian iron ore. The manganese ore was impregnated with Fe2O3 and the iron ore was impregnated with Mn2O3 with the goal of forming a combined Fe/Mn oxygen carrier. The impregnated ore's physical characteristics were assessed by SEM, BET and XRD analysis. Measurements of the attrition resistance and crushing strength were used to investigate the mechanical robustness of the oxygen carriers. The impregnated ore's mechanical and physical properties were clearly enhanced by the impregnation method, with boosts in crushing strength of 11-26% and attrition resistance of 37-31% for the impregnated iron and manganese ores, respectively. Both the unmodified and impregnated ore's reactivity, for the conversion of gaseous fuel (CH4 and syngas) and gaseous oxygen release (CLOU potential) were investigated using a bench-scale quartz fluidised-bed reactor. The impregnated iron ore exhibited a greater degree of syngas conversion compared to the other samples examined. Iron ore based oxygen carrier's syngas conversion increases with the number of oxidation and reduction cycles performed. The impregnated iron ore exhibited gaseous oxygen release over extended periods in an inert atmosphere and remained at a constant 0.2% O2 concentration by volume at the end of this inert period. This oxygen release would help ensure the efficient use of solid fuels. The impregnated iron ore's reactivity for CH4 conversion was similar to the reactivity of its unmodified counterpart. The unmodified manganese ore converted CH4 to the greatest extent of all the samples tested here, while the impregnated manganese ore exhibited a decrease in reactivity with respect to syngas and CH4 conversion

Емпіричний аналіз впливу збільшення населення на економічне зростання найбільш густонаселеної країни Африки

The concern about population growth in many developing countries has become a burning issue in the literature. Furthermore, many divergent views exist on whether increasing population is useful or harmful to growth in the economy. This study therefore, analysed the impact of population increase on economic growth in Nigeria, as an Africa’s most populous country. The study employed time series data from 1985–2018 using the framework of the Autoregressive Distributed Lag (ARDL) Model. The findings of this study revealed that the population growth of the economy supports economic growth both in the short and long term. However, it may become explosive in the long run if vital measures are not taken to control it. Since population increase has a huge impact on economic growth, the government should take steps to ensure that the population continues to increase the country’s growth trajectory by equipping the workforce with the appropriate skills. Therefore, to enhance sustainable development, the study proposes to formulate an effective government policy in order to ensure the growing labour force with jobs and modern qualification skills in accordance with the requirements of the labor market and increasing the country’s GDP. Also, there is need to formulate effective financial policies and support competitive interest rates in order to improve the economy’s savings rate. Effective monitoring of the economy’s capital-output ratio should ensure its increase in GDP, and the prohibition of effective state policy should be enacted to maintain stable and non-escalating population growth rate.Занепокоєння зростанням населення в багатьох країнах, що розвиваються, стало актуальним питанням у літературі. Крім того, існує багато різних поглядів на те, корисне чи шкідливе збільшення чисельності населення для зростання економіки. Зважаючи на це, у статті проаналізовано вплив збільшення населення на економічне зростання в Нігерії, як найбільш густонаселеній країні Африки. У дослідженні використано дані часових рядів за період 1985–2018 рр. та модель авторегресії і розподіленого лага (ARDL). Результати дослідження показали, що зростання чисельності населення в економіці сприяє економічному зростанню, як у короткостроковій, так і в довгостроковій перспективі. Однак у довгостроковій перспективі воно може стати вибухонебезпечним, якщо не вжити життєво важливих заходів для його контролю. З огляду на те, що збільшення чисельності населення має величезний вплив на економічне зростання, уряду варто вживати заходів задля забезпечення того, щоб населення продовжувало збільшувати траєкторію зростання країни, оснащуючи робочу силу відповідними навичками. Отже, для посилення сталого розвитку в дослідженні пропонується сформулювати ефективну державну політику з метою забезпечення зростаючої робочої сили робочими місцями та сучасними кваліфікаційними навичками відповідно до вимог ринку праці і збільшення ВВП країни. Крім того, існує необхідність у формуванні ефективної фінансової політики та підтримці конкурентних процентних ставок з метою підвищення рівня заощаджень в економіці. Ефективний моніторинг співвідношення капіталу та зростання в економіці має забезпечити його збільшення у ВВП, а запровадження ефективної державної політики дозволить підтримувати стабільні та не ескалаційні темпи приросту населення

Thresholds of biodiversity and ecosystem function in a forest ecosystem undergoing dieback

Ecological thresholds, which represent points of rapid change in ecological properties, are of major scientific and societal concern. However, very little research has focused on empirically testing the occurrence of thresholds in temperate terrestrial ecosystems. To address this knowledge gap, we tested whether a number of biodiversity, ecosystem functions and ecosystem condition metrics exhibited thresholds in response to a gradient of forest dieback, measured as changes in basal area of living trees relative to areas that lacked recent dieback. The gradient of dieback was sampled using 12 replicate study areas in a temperate forest ecosystem. Our results provide novel evidence of several thresholds in biodiversity (namely species richness of ectomycorrhizal fungi, epiphytic lichen and ground flora); for ecological condition (e.g. sward height, palatable seedling abundance) and a single threshold for ecosystem function (i.e. soil respiration rate). Mechanisms for these thresholds are explored. As climate-induced forest dieback is increasing worldwide, both in scale and speed, these results imply that threshold responses may become increasingly widespread

Gluon Propagator on Coarse Lattices in Laplacian Gauges

The Laplacian gauge is a nonperturbative gauge fixing that reduces to Landau gauge in the asymptotic limit. Like Landau gauge, it respects Lorentz invariance, but it is free of Gribov copies; the gauge fixing is unambiguous. In this paper we study the infrared behavior of the lattice gluon propagator in Laplacian gauge by using a variety of lattices with spacings from $a = 0.125$ to 0.35 fm, to explore finite volume and discretization effects. Three different implementations of the Laplacian gauge are defined and compared. The Laplacian gauge propagator has already been claimed to be insensitive to finite volume effects and this is tested on lattices with large volumes.Comment: RevTex 4.0, 14 pages, 9 colour figures; Correction to Reference

The Principal Element of a Frobenius Lie Algebra

We introduce the notion of the \textit{principal element} of a Frobenius Lie algebra \f. The principal element corresponds to a choice of F\in \f^* such that $F[-,-]$ non-degenerate. In many natural instances, the principal element is shown to be semisimple, and when associated to \sl_n, its eigenvalues are integers and are independent of $F$. For certain ``small'' functionals $F$, a simple construction is given which readily yields the principal element. When applied to the first maximal parabolic subalgebra of \sl_n, the principal element coincides with semisimple element of the principal three-dimensional subalgebra. We also show that Frobenius algebras are stable under deformation.Comment: 10 page

Deuteron Electroweak Disintegration

We study the deuteron electrodisintegration with inclusion of the neutral currents focusing on the helicity asymmetry of the exclusive cross section in coplanar geometry. We stress that a measurement of this asymmetry in the quasi elastic region is of interest for an experimental determination of the weak form factors of the nucleon, allowing one to obtain the parity violating electron neutron asymmetry. Numerically, we consider the reaction at low momentum transfer and discuss the sensitivity of the helicity asymmetry to the strangeness radius and magnetic moment. The problems coming from the finite angular acceptance of the spectrometers are also considered.Comment: 30 pages, Latex, 7 eps figures, submitted to Phys.Rev.C e-mail: [email protected] , [email protected]

Disconnect between policy and practice in developing countries : evidence of managing e-waste from Nigeria.

There are insufficient management functions that begin with planning, institutional arrangements and technical handling of e-waste materials in Nigeria. Modern trends in recycling still fall short of global practices. This study examined Waste Electrical and Electronic Equipment (WEEE) management strategies in Southeastern Nigeria with a view to suggesting appropriate implementable measures. It used an investigative approach through questionnaire administration. Twenty local government areas were purposively selected from five mutually exclusive strata of states. Data from 36 government agencies/offices were analyzed using percentage and linear multiple regression. Results revealed that WEEE management strategies were inadequate. The study concluded that WEEE management strategies were inapt and poorly implemented. Regulatory bodies should therefore urgently embrace and adopt appropriate management strategies, conduct periodic inventories of WEEE types and quantity and encourage the set-up and enforcement of cutting edge standards for modern facilities designated for the disposal of e-waste materialshttp://www.tandfonline.com/loi/rajs20hj2020Graduate School of Technology Management (GSTM