Kind Of Transitions Research Articles

Influence lines for schedule networks

An influence line graphs for project planning show how the changes of a selected activity duration affect the project duration. The name comes from the structural analysis where influence lines show on the ordinates of a graph the variation of the magnitude of, e.g., the bending moment at a specific point as a unit load traverses across the structure. This paper examines the principles of project planning influence lines: it discusses how to depict the six criticality types of activities, and it also shows what kind of transitions are possible among the criticality types. The findings help the greater understanding of the effects of the activity duration changes on the project duration.

From Individual Knowledge to Collective Practice - Exploring Transitions in Knowledge Creation

In this study, we trace transitions in knowledge creation. The study explores what kind of transitions occur between individual and collective knowledge creation in the process of creating new coll...

Phase Transition in Recovery Process of Complex Networks**Supported by the National Natural Science foundation of China under Grant No 11474221.

The dynamic characteristic of complex network failure and recovery is one of the main research topics in complex networks. Real world systems such as traffic jams and Internet recovery could be described by the complex network theory. We propose a model to study the recovery process in complex networks. Two different recovery mechanisms are considered in three kinds of networks: external recovery and internal recovery. By simulating the process of the nodes recovery in networks, it is found that the system exhibits the feature of first-order phase transition only when the external recovery is considered. Internal recovery cannot induce such a kind of transitions. As external recovery and internal recovery coexist on networks, the systems will retain the most efficient part of external recovery and internal recovery. Meanwhile, a hysteresis could be observed when increasing or decreasing the failure probability. Finally, a largest degree node protection strategy is proposed for improving the robustness of networks.

Non-singular transitions between assembly modes of 2-DOF planar parallel manipulators with a passive leg

In the field of parallel manipulators, the possibility of changing assembly mode without passing through a singular configuration is well known. This kind of transitions was studied in detail for planar 3-DOF manipulators. This paper focuses on 2-DOF parallel manipulators actuated by two RRR legs and constrained to a 2-DOF motion by a passive leg. It first shows that when the platform movement is constrained to rotations and translations along a single direction, nonsingular assembly mode transitions are possible. The direct and inverse kinematic problems of the mechanism are solved. The singularity conditions are written in explicit form and geometrically interpreted. Numerical examples of nonsingular assembly mode transitions are then given. Subsequently, the paper proves that if the platform is instead constrained to translational motions, nonsingular assembly mode transitions become impossible. Remarks on the generalization of the results to a wider class of 2-DOF planar manipulators are finally given.

Social work: a profession in flux

PurposeThe purpose of this paper is to describe the current context of social work as a profession and some of the major transition factors that are affecting social workers and social work organisations.Design/methodology/approachThe paper first explores what social work is, and how it has developed as a profession. It reflects on social work academia and the place of social work educators and researchers. It then goes on to consider three factors that are having a major influence on social work as a profession: concepts of risk; personalisation; and the multi‐disciplinary environment.FindingsThe implications of these factors and the kind of transitions they are driving are discussed in the context of some of the potential implications for professional learning.Research limitations/implicationsThe paper does not aim to provide a comprehensive overview of all the factors that are affecting contemporary social work – the aim is to offer contextual information to help the reader consider some of the forces at play in social work. The paper does not introduce new empirical evidence, rather it identifies gaps in the existing evidence about these key influential factors.Social implicationsThe implications of social work in transition for society are that efficacy may be impeded if the profession is too inward looking.Originality/valueThis paper draws from the empirical and conceptual work of others – here the aim is to provide a broad overall context within which to consider the more detailed implications set out in further papers in the present issue.

High Temperature Mechanical Spectrum and Interstitial Oxygen in YBaCuFeO<sub>5+δ</sub>

Double perovskite oxide YBaCuFeO5+δ samples (labeled as “as-prepared”) were sintered by a solid-state reaction technique. Mechanical spectra of as-prepared sample were measured under vacuum condition from room temperature up to 720K by the reed vibration method. In the first heating run, two internal friction peaks were observed around 380 and 620K (labeled as P1 and P2, respectively) in YBaCuFeO5+δ. In the subsequent cooling run, both of them disappeared and a small step-like decrease of the internal friction around 500K was found. This step-like change was reproduced in the following thermal cycles. Thermogravimetric analysis (TGA) was also performed in order to monitor the oxygen content of the sample. It showed that the interstitial oxygen concentration decreased in the first heating run. The interstitial oxygen relaxation is suggested to be the origin of P1 peak. In dielectric measurements, a dielectric loss peak appeared around the temperature of the P2 internal friction peak and the peak temperature was independent on the measuring frequency. It is expected that P2 is associated with some kind of transitions of the interstitial oxygen. Further mechanical loss measurement of the annealed sample and scanning electron microscopy characterizing the as-prepared and annealed samples, provided more information on the interstitial oxygen in YBaCuFeO5+δ samples.

Invited Commentary: Toward a More Comprehensive Social Epidemiology of Marital Trajectories and Mortality

In this issue of the Journal, Dupre et al. (Am J Epidemiol. 2009;170(5):546-555) use data from a nationally representative cohort of older US adults to examine the association of current marital status, timing of first marriage, number and kind of transitions out of marriage, and durations spent in various marital statuses with the risk of all-cause mortality. Their study offers a wealth of empirical findings that make important contributions to research on the relation between marital status and mortality. The richness of their findings suggests the need for future research to provide a more complete account of the mechanisms that lead from specific dimensions of marital status (and family structure more broadly) to mortality or other health outcomes over the life course.

Causation and constitution in system dynamics: modelling a socially constituted world

AbstractThis paper discusses the claim that System Dynamics models are unable to represent constitutional change. They do represent state transitions, but not constitutional transitions. Because the latter kind of transitions is the rule rather than the exception in the study of social phenomena, this inability has serious consequences. First of all, it leads to a neglect of constitutional issues; causal models blind us for constitutional change. Secondly, and even more seriously, it implies a direct threat to the validity of the causal models, themselves. These consequences are discussed and illustrated by referring to two case studies. Finally, the question is discussed of whether Group Model Building handles constitutional issues any better than System Dynamics does. Although Group Model Building does contribute important epistemological insights, it fails, just as is the case in System Dynamics, to deal with constitutional change. Copyright © 2006 John Wiley & Sons, Ltd.

Relaxation and Lineshape of the 500.4-GHz Line of Ozone Perturbed by N2 and O2

N2- and O2-broadened linewidths of the J = 342,32 ← 341,33 transition of ozone located at 500.4 GHz have been measured at three temperatures in the 247–295 K range by using a video-type spectrometer. Besides the Voigt profile commonly used as theoretical model for millimeter-wave investigations, different other theoretical lineshapes, the speed-dependent Voigt profile, the Galatry profile, and the speed-dependent Galatry profile, have been considered to analyze the experimental spectra, to retrieve the pressure-broadening parameters, and to give an account of the pointed out line-narrowing effect. The results for O3 perturbed by N2 and O2 are finally compared to calculations based on the complex semiclassical theory of Robert and Bonamy, and with previous reported values involving the same kind of transitions. Finally, it is shown that observed line narrowings result nearly exclusively from the dependence of relaxation on molecular speeds.

Ground-γband coupling in heavy deformed nuclei and SU(3) contraction limit

We derive analytic expressions for the energies and $B(E2)$-transition probabilities in the states of the ground and $\gamma$ bands of heavy deformed nuclei within a collective Vector-Boson Model with SU(3) dynamical symmetry. On this basis we examine the analytic behavior of the SU(3) energy splitting and the B(E2) interband transition ratios in the SU(3) contraction limits of the model. The theoretical analyses outline physically reasonable ways in which the ground-$\gamma$ band coupling vanishes. The experimental data on the lowest collective states of even-even rare earth nuclei and actinides strongly support the theoretical results. They suggest that a transition from the ground-$\gamma$ band coupling scheme to a scheme in which the ground band is situated in a separate irreducible representation of SU(3) should be realized towards the midshell regions. We propose that generally the SU(3) group contraction process should play an important role for such a kind of transitions in any collective band coupling scheme in heavy deformed nuclei.

Structure Transformations of the Decagonal and Icosahedral Phases in Quaternary Alloys.

ABSTRACTAn investigation of the phase transformations experienced by the decagonal and icosahedral phases in two different quaternary -alloys is carried out. The transformation in the decagonal phase of Al-Cu-Co-Si alloy is induced by the electron radiation in a transmission electron microscope. However, in the icosahedral phase of Al-Cu-Co-Fe alloy this transformation is induced by annealing. Electron diffraction patterns obtained from both phases suggest that the deformation mechanism involved in these kind of transitions is related with twinning