290 research outputs found

    An Examination of the Teaching of Missional Concepts of Christian Discipleship and their Potential for Creating an Attitudinal Change at Berea Lutheran Church, Richfield, Minnesota

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    Tiaden, Kevin N. “An Examination of the Teachings of Missional Concepts of Christian Discipleship and their Potential for Creating Attitudinal Change at Berea Lutheran Church, Richfield, Minnesota.” Doctor of Ministry. Major Applied Project, Concordia Seminary, 2017. 132 pp. The purpose of this study is to examine the teaching of missional principles of discipleship at Berea Lutheran Church. I examine the attitudinal changes that take place as a result of this class. The first step in this process is looking at what those missional and Biblical principles are and then creating a method of teaching them in a large group setting while maintaining firm standing in the teaching of my church body, the LCMS. Many of the concepts for these teachings come from 3DM Ministries in their work in creating disciples and from www.vergenetwork.org. The final evaluation is to examine the changes in attitude towards discipleship within the congregation where I serve. This will set a base for further growth in our lives following Jesus here at Berea and in the church at large

    Concept Refinement of a Payload Derived Position Acquisition System for Parachute Recovery Systems

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    20th AIAA Aerodynamic Decelerator Systems Technology Conference and Seminar, Seattle, WA, May 4-7 2009.The paper covers the continued development of a Payload Derived Position Acquisition System (PDPAS) to overcome current limitations posed on recovering the trajectory data for a generic parachute recovery system (PRS). The PDPAS is an instrumentation set and software algorithm that is to be installed onto PRS in order to estimate PRS state vector parameters in real-time for testing and operational use. The development of the PDPAD has progressed to a point where it is providing quality data and is ready for development into a usable instrumentation package. The paper discusses the concept of the PDPAS, the first implementation of the PDPAS, changes made to the PDPAS due to continued development, and the steps for needed for the PDPAS to be a validated instrumentation package

    α-Hydroxyketone Synthesis and Sensing by Legionella and Vibrio

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    Bacteria synthesize and sense low molecular weight signaling molecules, termed autoinducers, to measure their population density and community complexity. One class of autoinducers, the α-hydroxyketones (AHKs), is produced and detected by the water-borne opportunistic pathogens Legionella pneumophila and Vibrio cholerae, which cause Legionnaires’ disease and cholera, respectively. The “Legionella quorum sensing” (lqs) or “cholera quorum sensing” (cqs) genes encode enzymes that produce and sense the AHK molecules “Legionella autoinducer-1” (LAI-1; 3-hydroxypentadecane-4-one) or cholera autoinducer-1 (CAI-1; 3-hydroxytridecane-4-one). AHK signaling regulates the virulence of L. pneumophila and V. cholerae, pathogen-host cell interactions, formation of biofilms or extracellular filaments, expression of a genomic “fitness island” and competence. Here, we outline the processes, wherein AHK signaling plays a role, and review recent insights into the function of proteins encoded by the lqs and cqs gene clusters. To this end, we will focus on the autoinducer synthases catalysing the biosynthesis of AHKs, on the cognate trans-membrane sensor kinases detecting the signals, and on components of the down-stream phosphorelay cascade that promote the transmission and integration of signaling events regulating gene expression

    Phase field analysis of eutectic breakdown.

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    In this paper an isotropic multi-phase-field model is extended to include the effects of anisotropy and the spontaneous nucleation of an absent phase. This model is derived and compared against a published single phase model. Results from this model are compared against results from other multi-phase models, additionally this model is used to examine the break down of a regular two dimensional eutectic into a single phase dendritic front

    Применение иерархических игр для поддержки и развития отраслей малого бизнеса моногородов

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    В предоставленной статье рассматривается вопрос монозависимых городов в России, приводящий к проблеме безработицы. В качестве предполагаемой возможности поспособствовать ее решению предлагается рассмотреть возможность применения иерархических игр в качестве средства для развития отраслей малого бизнеса в моногороде

    Phase-Field Formulation for Quantitative Modeling of Alloy Solidification

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    A phase-field formulation is introduced to simulate quantitatively microstructural pattern formation in alloys. The thin-interface limit of this formulation yields a much less stringent restriction on the choice of interface thickness than previous formulations and permits to eliminate non-equilibrium effects at the interface. Dendrite growth simulations with vanishing solid diffusivity show that both the interface evolution and the solute profile in the solid are well resolved

    Phase-field modeling of microstructural pattern formation during directional solidification of peritectic alloys without morphological instability

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    During the directional solidification of peritectic alloys, two stable solid phases (parent and peritectic) grow competitively into a metastable liquid phase of larger impurity content than either solid phase. When the parent or both solid phases are morphologically unstable, i.e., for a small temperature gradient/growth rate ratio (G/vpG/v_p), one solid phase usually outgrows and covers the other phase, leading to a cellular-dendritic array structure closely analogous to the one formed during monophase solidification of a dilute binary alloy. In contrast, when G/vpG/v_p is large enough for both phases to be morphologically stable, the formation of the microstructurebecomes controlled by a subtle interplay between the nucleation and growth of the two solid phases. The structures that have been observed in this regime (in small samples where convection effect are suppressed) include alternate layers (bands) of the parent and peritectic phases perpendicular to the growth direction, which are formed by alternate nucleation and lateral spreading of one phase onto the other as proposed in a recent model [R. Trivedi, Metall. Mater. Trans. A 26, 1 (1995)], as well as partially filled bands (islands), where the peritectic phase does not fully cover the parent phase which grows continuously. We develop a phase-field model of peritectic solidification that incorporates nucleation processes in order to explore the formation of these structures. Simulations of this model shed light on the morphology transition from islands to bands, the dynamics of spreading of the peritectic phase on the parent phase following nucleation, which turns out to be characterized by a remarkably constant acceleration, and the types of growth morphology that one might expect to observe in large samples under purely diffusive growth conditions.Comment: Final version, minor revisions, 16 pages, 14 EPS figures, RevTe

    Relationship between solidification microstructure and hot cracking susceptibility for continuous casting of low-carbon and high-strength low-alloyed steels: A phase-field study

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    © The Minerals, Metals & Materials Society and ASM International 2013Hot cracking is one of the major defects in continuous casting of steels, frequently limiting the productivity. To understand the factors leading to this defect, microstructure formation is simulated for a low-carbon and two high-strength low-alloyed steels. 2D simulation of the initial stage of solidification is performed in a moving slice of the slab using proprietary multiphase-field software and taking into account all elements which are expected to have a relevant effect on the mechanical properties and structure formation during solidification. To account for the correct thermodynamic and kinetic properties of the multicomponent alloy grades, the simulation software is online coupled to commercial thermodynamic and mobility databases. A moving-frame boundary condition allows traveling through the entire solidification history starting from the slab surface, and tracking the morphology changes during growth of the shell. From the simulation results, significant microstructure differences between the steel grades are quantitatively evaluated and correlated with their hot cracking behavior according to the Rappaz-Drezet-Gremaud (RDG) hot cracking criterion. The possible role of the microalloying elements in hot cracking, in particular of traces of Ti, is analyzed. With the assumption that TiN precipitates trigger coalescence of the primary dendrites, quantitative evaluation of the critical strain rates leads to a full agreement with the observed hot cracking behavior. © 2013 The Minerals, Metals & Materials Society and ASM International

    Eutectic colony formation: A phase field study

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    Eutectic two-phase cells, also known as eutectic colonies, are commonly observed during the solidification of ternary alloys when the composition is close to a binary eutectic valley. In analogy with the solidification cells formed in dilute binary alloys, colony formation is triggered by a morphological instability of a macroscopically planar eutectic solidification front due to the rejection by both solid phases of a ternary impurity that diffuses in the liquid. Here we develop a phase-field model of a binary eutectic with a dilute ternary impurity and we investigate by dynamical simulations both the initial linear regime of this instability, and the subsequent highly nonlinear evolution of the interface that leads to fully developed two-phase cells with a spacing much larger than the lamellar spacing. We find a good overall agreement with our recent linear stability analysis [M. Plapp and A. Karma, Phys. Rev. E 60, 6865 (1999)], which predicts a destabilization of the front by long-wavelength modes that may be stationary or oscillatory. A fine comparison, however, reveals that the assumption commonly attributed to Cahn that lamella grow perpendicular to the envelope of the solidification front is weakly violated in the phase-field simulations. We show that, even though weak, this violation has an important quantitative effect on the stability properties of the eutectic front. We also investigate the dynamics of fully developed colonies and find that the large-scale envelope of the composite eutectic front does not converge to a steady state, but exhibits cell elimination and tip-splitting events up to the largest times simulated.Comment: 18 pages, 18 EPS figures, RevTeX twocolumn, submitted to Phys. Rev.

    A phase-field model investigating the role of elastic strain energy during the growth of closely spaced neighbouring interphase precipitates

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    A multi-phase field method is developed to investigate the effects of transformation strain on the transformation kinetics, thermodynamic stability and pairing of interphase precipitates in micro-alloyed steels. The model conserves homogeneity of stress in the diffuse interface between elastically inhomogeneous phases and provides an explanation of the mechanism resulting in the pairing of two adjacent interphase precipitates. Several scenarios of inhomogeneous elastic conditions have been considered. The simulations for a situation where only the interfacial energy is considered to contribute to the transformation show that this energy can lead to the establishment of a neck between two neighbouring precipitates. However, if sufficient time is given, one of the precipitates will completely dissolve into its neighbouring particle. On the other hand, when both strain and interfacial energies act on the system, the bridge between the particles becomes stabilised leading to the pairing of the particles. This is a result of the particles tendency to minimise the strain energy due to the excessive strain field generated by the neck between the two particles
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