Room temperature ferromagnetism and photoluminescence of nanocrystalline Zn1 − xCoxO thin films prepared by sol–gel MOD

Zn_1???xCo_xO (ZC) [x?=?0, 1, 3, 5, 7 and 9?mol%] thin films were prepared by sol–gel combined metallo-organic decomposition method. The films were deposited on the Si substrate with spin-coating technique and annealed at 600?°C for 3?h. X-ray diffraction pattern shows the formation hexagonal wurtzite phase and distortion (c/a) decreases with increasing Co concentration in ZnO. The average grain size is measured using Scherer relation. Atomic force microscopy is used to confirm the formation of nanograins resulted by the use of polyethylene glycol as surfactant. The photoluminescence was recorded by using He-Cd laser of excitation wavelength 325?nm in wavelength region of 350–650?nm which exhibits some influence of Co doping on the multiplication of defects such as O vacancies, Zn interstitials and grain boundary defects. All thin films show room temperature ferromagnetism except pure ZnO which is diamagnetic and 9?mol% of Co shows paramagnetism. This behaviour is interpreted as due to fluctuations in the magnetic ordering, depending on grain size and site location in grain boundaries or oxygen vacancies.     

Nanoindentation creep behavior of grain boundary in pure magnesium

Nanoindentation creep tests were performed at the grain boundary and grain interior in pure magnesium. The grain boundary showed a high strain rate sensitivity exponent and was dominated by grain boundary sliding due to the high diffusion rate at the grain boundary. The grain boundary affected the deformation behavior of the area at a distance of 2 µm into the grain interior. On the other hand, the grain interior had a low strain rate sensitivity exponent, because its matrix was too large to be influenced by the grain boundary. The deformation mechanism in the grain interior was determined to be dislocation slip.     

Neutron and X-ray diffraction studies and cohesive interface model of the fatigue crack deformation behavior

The crack-tip deformation behavior during a single overload, fatigue test of ferritic stainless steel, and Ni-based HAYNES 230 superalloy is studied at different structural levels using (1) neutron-diffraction, from which both the elastic-lattice strain and volume-averaged total dislocation densities are obtained, (2) polychromatic X-ray microdiffraction to probe the geometrically necessary dislocations and boundaries distribution, and (3) an irreversible and hysteretic cohesive interface model which has been implemented into a finite element framework to simulate the stress/strain evolution near the fatigue crack tip. Neutron strain measurements and finite element simulations are in qualitative agreement on the macroscopic length scale. Large plastic deformation induced by the overload and the resulting compressive residual strains are observed in front of the crack tip after the overload, and are the principal reason for the fatigue-crack-growth retardation. Strong strain gradients surrounding the crack propagation result in the formation of a high density of geometrically necessary dislocations near the fractured surface and cause local lattice rotations on the submicron level.     

high-resolution electron microscopy at a (113) symmetric Thermally activated step motion observed by tilt grain-boundary in aluminium

Grain-boundary migration is demonstrated to proceed by lateral propagation of a small step in a (113), [110] symmetric Al tilt grain-boundary. In-situ high-resolution (transmission) electron microscopy (HREM) at 523K allowed the study of atomic-scale detail at video rates during the migration process. The grain-boundary translational states on both sides of the step are identical, which leads to a step dislocation. This defect can move laterally by a combination of climb and glide. Dynamic HREM images indicate considerable atomic agitation within the dislocation core. A detailed temporal analysis of the step movements shows small random displacements of the dislocation core.     

Formation of ω -Al7Cu2Fe phase during laser processing of quasicrystal-forming Al–Cu–Fe alloy

The formation of an ω-Al₇Cu₂Fe phase during laser cladding of quasicrystal-forming Al₆₅Cu_23.3Fe_11.7 alloy on a pure aluminium substrate is reported. This phase is found to nucleate at the periphery of primary icosahedral-phase particles. A large number of ω-phase particles form an envelope around the icosahedral phase. On the outer side, they form an interface with an α-Al solid solution. Detailed transmission electron microscopic observations show that the ω phase exhibits an orientation relationship with the icosahedral phase. Analysis of experimental results suggests that the ω phase forms by precipitation on an icosahedral phase by heterogeneous nucleation and grows into the aluminium-rich melt until supersaturation is exhausted. The microstructural observations are explained in terms of available models of phase transformations.     

Log-normal nanograin-size distributions in nanostructured composites

A key challenge in the fabrication of superhard nanocomposite films is how to control the distribution of grain sizes in these materials. High-resolution transmission electron microscopy has been used to measure nanograin-size distributions in the Ti–B–N films with various B contents. The results show that the mean grain size decreases with increase of B content and the grain-size distribution conforms to a log-normal function when the hardness approaches a maximum value. The transition from normal to log-normal distributions can be determined by analysis in terms of a minimum information criterion. The origin of a log-normal size distribution probably results from heterogeneity arising from a diffusion-drift process.     

Design strategy for microalloyed ultra-ductile magnesium alloys

This article describes a design strategy deployed in developing ultra-ductile Mg alloys based on a microalloying concept, which aims to restrict grain growth considerably during alloy casting and forming. We discuss the efficiency of the design approach, and evaluate the resulting microstructural and mechanical properties. After processing, the so-designed alloys ZQCa3 (Mg–3Zn–0.5Ag–0.25Ca–0.15Mn, in wt.%) and ZKQCa3 (Mg–3Zn–0.5Zr–0.5Ag–0.25Ca–0.15Mn, in wt.%) reveal very fine grains (<10 µm), high ductility (elongation to fracture of up to 30%) at moderate strength or high strength (ultimate tensile strength of up to 350 MPa) at reasonable ductility. These properties are explained based on thermodynamic modelling, microstructure analysis including transmission electron microscopy studies, and microstructural and mechanical testing after annealing, and are compared to a related commercial alloy (ZK31).     

Enhancement on the faceted growth and the coarsening of the MnBi primary phase during the directional solidification under a high magnetic field

The effect of a high magnetic field on the morphology of the MnBi primary phase during the directional solidification has been investigated experimentally and the results show that an application of a high magnetic field has enhanced the faceted growth and the coarsening of the MnBi primary phase. This may be attributed to the effect of a high magnetic field on the diffusion of the solute Mn and the growth anisotropy of the MnBi crystal.     

Health,Finances, Religious Involvement,and Life Satisfaction of Older Adults

ABSTRACT

This study examines the patterns and relationships between twelve independent variables and the expressed subjective well-being of older adults within that classic community setting of the Lynds' “Middletown.” The twelve variables include measures of church attendance, religious activity, religious conservatism/liberalism, subjective health status, social participation, importance of leisure, participation in physical activity, age, sex, marital status, and level of education.     

Coping Response Inventory: Assessing coping among Iranian college students and introductory development of an adapted Iranian Coping Response Inventory (CRI)

Coping is related to mental and physical health outcomes, but cultural and societal differences may influence its nature and structure. This study reports on the adaptation of the Coping Responses Inventory for Adult (CRI-A) to the Iranian social and cultural context. Study 1 was designed to obtain qualitative data and test the construct and discriminative validity of coping scales. Factor analysis of the CRI and Iranian items yielded seven factors: Religious Coping, Problem Solving, Cognitive Avoidance, Positive Reappraisal, Seeking Guidance and Support, Seeking Alternative Rewards, and Acceptance/Resignation. Internally, consistencies varied considerably from 0.92 to 0.53. All sub-scales from the Coping Responses Inventory for Adult (CRI-A) were resistant to social desirability biases with the exception of Religious Coping and Problem Solving. In Study 2, the replicability of the adapted CRI-A factorial structure and concurrent validity for the newly developed religious coping sub-scale was demonstrated. Given the importance of the role of religious coping in health and well-being outcomes, the expression and use of which may be substantially influenced by cultural practices and norms, it is recommended that future research pursues the validation of context-specific constructs of religious and spiritual coping.