Using Facebook for Government Public Relations Campaigns: Relationship between Information Seeking Attitude and Effectiveness of Public Relations Outcomes for Facebook

Though government departments rely heavily on different techniques for Public Relations (PR), the fundamental questions related to the effectiveness of social media as a PR tool remains unanswered. The study aims to find out how Facebook has an impact on the effectiveness of public relations outcomes for government department's public relations activities. From a sample of 300 respondents a survey was conducted. It was found that there is a positive correlation between respondents' attitude on Facebook information seeking scale and Facebook impact on effectiveness of public relations outcomes. Moreover it was also found that use of Facebook is creating a favorable attitude for target audience; knowledge levels; content of positioned values; quality of opinion; customer satisfaction; tone of opinion and mutual trust, satisfaction and commitment. Whereas, for 'mutual control' and 'relationship maturity' in PR activities of the government there is need for more research.&nbsp

A Review of Computational Modeling Techniques in Study and Design of Shape Memory Ceramics

Shape memory ceramics are a unique family of shape memory materials with a wide variety of applications, such as ultra-high energy dissipation and high-temperature actuation. Along with significant progress in the experimental study of zirconia-based shape memory ceramics in recent years, computational simulations have exhibited powerful capabilities in revealing nano/microstructure-dependent deformation and failure mechanisms in these materials. In this work, we review the recent progress in understanding the phase transformation behavior in shape memory ceramics, focusing on computational modeling of zirconia-based ceramics. Electronic structure calculations have provided new data on the phase stability and surface properties of shape memory ceramics. At the nanometer length scale, molecular dynamics simulations have captured fundamental information about martensitic phase transformation and the effects of grain boundaries and defects on mechanical response of bi- and polycrystalline zirconia-based ceramics. At the micrometer length scale, advanced phase-field models have shown the ability to predict morphological evolution of microstructures and the corresponding mechanical responses in good agreement with experimental observations. Despite the recent multiscale computational advancements, further developments are required to establish processing-structure-property-performance relations that will lead to reliable and practical strategies for designing zirconia-based (or other) ceramics with improved and sustained shape memory responses. This article critically reviews current computational modeling techniques and provides an outlook for the study and design of the next generation of shape memory ceramics

Shape Memory Effect and Pseudoelasticity Behavior in Tetragonal Zirconia Polycrystals: A Phase Field Study

Martensitic tetragonal-to-monoclinic transformation in zirconia is a double-edged sword , enabling transformation toughening or shape memory effects in favorable cases, but also cracks and phase degradation in undesirable scenarios. In stressed polycrystals, the transformation can burst from grain to grain, enabling stress field shielding and toughening in an autocatalysis fashion. This transformation strain can be recovered by an adequate thermal cycle at low temperatures (when monoclinic is stable) to provide a shape memory effect, or by unloading at higher temperatures (when tetragonal is stable) to provide pseudoelasticity. We capture the details of these processes by mining the associated microstructural evolutions through the phase field method. The model is both stress and temperature dependent, and incorporates inhomogeneous and anisotropic elasticity. Results of simulations show an ability to capture the effects of both forward (T → M) and reverse (M → T) transformation under certain boundary conditions

A Review on Phase Field Modeling of Martensitic Phase Transformation

In the last few decades, the phase field method has shown tremendous capabilities of predicting microstructure evolutions at the mesoscale scale. This method was widely used for modeling martensitic phase transformation, where the displacive character was a challenging problem for the counterpart sharp interface approach. Martensitic phase transformation, which is an invariant plane stress twinning, drives a myriad of phase transition phenomena of paramount importance to many structural applications. This article provides a literature review of the past phase field modeling studies used to capture the formation and growth of martensite

Effect of Variant Strain Accommodation on the Three-Dimensional Microstructure Formation during Martensitic Transformation: Application to Zirconia

This paper computationally investigates the effect of martensitic variant strain accommodation on the formation of microstructural and topological patterning in zirconia. We used the phase-field technique to capture the temporal and spatial evolution of embryonic formation of the monoclinic phase in tetragonal single crystals. The three-dimensional simulations were able to capture the formation of all the possible monoclinic variants. We used the multivariant single embryo as an initial condition to mitigate the lack of nucleation criteria at the mesoscale. Without a priori constraint, the model can select the transformation path and final microstructure. The phase-field model was benchmarked against experimental studies on surface uplift formation in zirconia reported by Deville et al. (Acta Mater 2004;52:5697, Acta Mater 2004;52:5709). The simulations showed the excellent capabilities of the model in predicting the formation of a surface relief induced by the tetragonal to monoclinic martensitic transformation

Phase Field Modeling of Stress-Induced Tetragonal-to-Monoclinic Transformation in Zirconia and its Effect on Transformation Toughening

This paper proposes a two-dimensional elastic phase field model for capturing the effect of external stress on the tetragonal-to-monoclinic (T → M) phase transformation in zirconia. The model was able to predict the sensitivity of the monoclinic microstructural formation and evolution to the external loading conditions. The effect of stress on the T → M phase transformation was captured by explicitly applying stresses on the computational domain by entering them in the mechanical equilibrium equations as boundary conditions. Simulation results showed that, regardless of the stress loading direction, the monoclinic twinning plane always corresponded to {1 0 0} m. Results of simulations showed that external stress favors the production of monoclinic variants which exhibit transformation strains aligned with the applied stress direction. When applied to the transformation toughening phenomenon in zirconia, the model was able to elucidate the mechanisms of phase transformation ahead of a crack tip, including the generation of a compressive stress field responsible for the retardation of further crack growth. This work presents the first model capable of demonstrating the process of transformation toughening and crack closure in zirconia

Shape Memory Effect and Pseudoelasticity Behavior in Tetragonal Zirconia Polycrystals: A Phase Field Study

Martensitic tetragonal-to-monoclinic transformation in zirconia is a double-edged sword , enabling transformation toughening or shape memory effects in favorable cases, but also cracks and phase degradation in undesirable scenarios. In stressed polycrystals, the transformation can burst from grain to grain, enabling stress field shielding and toughening in an autocatalysis fashion. This transformation strain can be recovered by an adequate thermal cycle at low temperatures (when monoclinic is stable) to provide a shape memory effect, or by unloading at higher temperatures (when tetragonal is stable) to provide pseudoelasticity. We capture the details of these processes by mining the associated microstructural evolutions through the phase field method. The model is both stress and temperature dependent, and incorporates inhomogeneous and anisotropic elasticity. Results of simulations show an ability to capture the effects of both forward (T → M) and reverse (M → T) transformation under certain boundary conditions

Phase Field Modeling of Tetragonal to Monoclinic Phase Transformation at Zirconium Oxide

Tetragonal to monoclinic phase transformation at the zirconium oxide layer is an important factor in changing the oxidation kinetics and also promoting breakaway oxidation in Zircaloy fuel rod claddings. This transformation affects the stress state at the oxide layer close to the metal/oxide interface. The amplitude of these internal stresses can significantly change the kinetics of oxidation. In this work, we presented a phase field model to investigate the tetragonal to monoclinic phase transformation in zirconium oxide layer. All necessary driving forces including bulk free energy, interfacial energy and elastic energy were taken into account, and the symmetry reduction between parent and products has been assigned to different non-conserved order parameters. Transformation stages from nucleation, growth and coarsening of variants were simulated. Development of internal stresses due to this transformation, which is the source of oxidation breakaway, was studied