Spiritual and strategic leadership in pastoral ministry

https://place.asburyseminary.edu/ecommonsatsdissertations/1394/thumbnail.jp

Jamming transition in a two-dimensional open granular pile with rolling resistance

We present a molecular dynamics study of the jamming/unjamming transition in two-dimensional granular piles with open boundaries. The grains are modeled by viscoelastic forces, Coulomb friction and resistance to rolling. Two models for the rolling resistance interaction were assessed: one considers a constant rolling friction coefficient, and the other one a strain dependent coefficient. The piles are grown on a finite size substrate and subsequently discharged through an orifice opened at the center of the substrate. Varying the orifice width and taking the final height of the pile after the discharge as the order parameter, one can devise a transition from a jammed regime (when the grain flux is always clogged by an arch) to a catastrophic regime, in which the pile is completely destroyed by an avalanche as large as the system size. A finite size analysis shows that there is a finite orifice width associated with the threshold for the unjamming transition, no matter the model used for the microscopic interactions. As expected, the value of this threshold width increases when rolling resistance is considered, and it depends on the model used for the rolling friction.Comment: 9 pages, 6 figure

Inversion of spinning sound fields

A method is presented for the reconstruction of rotating monopole source distributions using acoustic pressures measured on a sideline parallel to the source axis. The method requires no \textit{a priori} assumptions about the source other than that its strength at the frequency of interest vary sinusoidally in azimuth on the source disc so that the radiated acoustic field is composed of a single circumferential mode. When multiple azimuthal modes are present, the acoustic field can be decomposed into azimuthal modes and the method applied to each mode in sequence. The method proceeds in two stages, first finding an intermediate line source derived from the source distribution and then inverting this line source to find the radial variation of source strength. A far-field form of the radiation integrals is derived, showing that the far field pressure is a band-limited Fourier transform of the line source, establishing a limit on the quality of source reconstruction which can be achieved using far-field measurements. The method is applied to simulated data representing wind-tunnel testing of a ducted rotor system (tip Mach number~0.74) and to control of noise from an automotive cooling fan (tip Mach number~0.14), studies which have appeared in the literature of source identification.Comment: Revised version of paper submitted to JASA; five more figures; expanded content with more discussion of error behaviour and relation to Nearfield Acoustical Holograph

Analysis of the velocity field of granular hopper flow

We report the analysis of radial characteristics of the flow of granular material through a conical hopper. The discharge is simulated for various orifice sizes and hopper opening angles. Velocity profiles are measured along two radial lines from the hopper cone vertex: along the main axis of the cone and along its wall. An approximate power law dependence on the distance from the orifice is observed for both profiles, although differences between them can be noted. In order to quantify these differences, we propose a Local Mass Flow index that is a promising tool in the direction of a more reliable classification of the flow regimes in hoppers

Financialization and the resource curse: the challenge of exchange rate management in Brazil

This repository item contains a working paper from the Boston University Global Economic Governance Initiative. The Global Economic Governance Initiative (GEGI) is a research program of the Center for Finance, Law & Policy, the Frederick S. Pardee Center for the Study of the Longer-Range Future, and the Frederick S. Pardee School of Global Studies. It was founded in 2008 to advance policy-relevant knowledge about governance for financial stability, human development, and the environment.A stable and competitive exchange rate is imperative for efforts to diversify an economy in an open economy setting. However, there are an increasing number of exogenous economic and political factors in Brazil and other emerging market economies that accentuate the difficulties of shifting toward a more developmentalist economic policy. Nevertheless, over the past decade or more Brazil has developed a broad array of tools that enable the country to address the exogenously determined factors related to exchange rate instability. These tools have been a modest success at best, but lay the groundwork for what may be the necessary economic policies and political conditions for a more comprehensive program to achieve stability‐led diversified growth in Brazil

ENVIRONMENTAL AND FINANCIAL IMPACT ASSESSMENT OF NATURAL GAS COGENERATION PLANTS IN THE INDUSTRIAL SECTOR

This paper presents a case study on the impact of the use of natural gas cogeneration plants in industrial facilities from food companies established in the State of São Paulo, aiming at the financial and greenhouse gases emissions (GHG) analysis. It is proposed a comparison between two different energy supply models for two manufacturing plants, the first one based on electricity supply from local grid and steam from natural gas fired steam generators, and a second model that considers the industries energy needs being partially supplied through natural gas cogeneration plants which are installed in each one of the companies. This study indicates the differences of the financial results for supplying electricity and steam in both models proposed, describing the main variations and the reasons for those, besides identifying the main current tariff benefits in the legislation for the different classes of power plants and Energy Market. The summarized greenhouse gases inventory is presented for both industries as well, and a later assessment of environmental impact from the studied cogeneration plants in the overall GHG emissions in the two proposed scenarios is done. Finally, it is presented the relation analysis between electricity and steam supplying costs if compared with the greenhouse gases emissions levels for both proposed scenarios, and how public policies can act in order to guide emissions decreasing, since São Paulo State has promulgated a law in which establishes a major GHG emissions reduction to 2020

Preliminary results on the Gaulish terra sigillata from the fish-salting production centre at Tróia

The fish-salting production centre at Troia received various imports of terra sigillata from the 1st century to the 6th century. Although it did not reach the significance of the African Red Slip Ware, Gaulish Sigillata is the second most important group of imports of this category on this archaeological site. The recognition of a Tiberian foundation level with Gaulish vessels dates the arrival of this tableware. Nevertheless, we agree with the assumption of previous studies that the majority of the pieces from this assemblage corresponds to the Claudian period onwards. The purpose of this paper is to present the current state regarding terra sigillata studies at Troia, more precisely related to the Gaulish productions and their significance in the largest fish-salting centre of the Roman Empire.O centro de produção de salgas de peixe de Troia recebeu inúmeras importações de terra sigillata entre o século I d.C. e o século VI d.C. Ainda que não tenha atingido a proporção da terra sigillata africana, a terra sigillata gálica é o segundo maior grupo de importação desta categoria neste sítio arqueológico. A identificação de um nível de fundação tiberiano com taças gálicas data a chegada desta cerâmica de mesa. Não obstante, validamos as conclusões obtidas em estudos anteriores que referem que a maioria das peças desta colecção deverá ser integrada a partir do período cláudio. O objectivo deste artigo é apresentar o estado actual dos estudos de terra sigillata de Troia, mais precisamente as produções gaulesas e o seu significado no maior centro de produção de salgas de peixe do Império Romano.info:eu-repo/semantics/publishedVersio