Electronegativity difference as a factor for evaluating the thermal stability of Al-rich metallic glasses

This article proposes a factor, the critical electronegativity difference Δx _cri, to correlate alloy composition with thermal stability and glass-forming ability of Al–Ni–RE (RE: Rare Earth element) ternary metallic glasses. The Al-rich metallic glasses with Δx > Δx _cri exhibit glassy behavior, whereas alloys with Δx < Δx _cri are nanocrystalline. Nanoglassy alloys occur when Δx ≈ Δx _cri. The best glass formers are located near Δx _cri. Furthermore, an equation has been deduced to calculate Δx _cri with varying RE covalent atomic radius.     

Magnetic properties of Mn-doped armchair ZnO nanotubes: a Monte Carlo study

The magnetic properties of a Mn-doped armchair ZnO nanotube have been studied using Monte Carlo simulation. The variation of zero-field-cooled and field-cooled magnetisation with reduced temperatures for different values of the dilution x (where x is the Mn concentration: Zn_1?xMn_xO) are given. The freezing temperatures and magnetisation vs. crystal field are calculated for different dilutions x. Finally, the hysteresis loops for different dilutions and temperatures are given for a fixed reduced temperature and crystal field. Superparamagnetic behaviour is observed for small values of x and low temperatures.     

Temporal stability of behavioural intention as a moderator of intention–health behaviour relationships

Seven prospective studies of health behaviours containing eight prospective datasets testing the moderating role of intention stability on intention–behaviour and past behaviour–behaviour relationships were examined within the context of the Theory of Planned Behaviour. The measure of intention stability was based on lack of change in intentions between the two measurement time points. Across different behaviours, samples and time frames more stable intentions were associated with intentions at time 1 that were stronger predictors of behaviour at time 2. Intention stability did not consistently moderate the past behaviour–behaviour relationship. Across studies the frequency-weighted mean correlation between intentions and behaviour was substantially greater for stable (r ₊?=?0.60) compared to unstable (r ₊?=?0.27) intentions (Z _difference?=?6.65, p?<?0.001). The past behaviour–behaviour correlation was also stronger for stable (r ₊?=?0.50, p?<?0.001) compared to unstable (r₊ ?=?0.34, p?<?0.001) intentions (Z _difference?=?3.12, p?<?0.01). Perceived behavioural control was the variable most strongly related to stable intentions. Implications for understanding the role of health cognitions in the performance of health behaviour are discussed.     

Electrical conductivity of Nd and Ce co-doped Gd2Zr2O7 ceramics

In this study, (Gd_{1? x} Nd _x )₂(Zr_{1? x} Ce _x )₂O₇ (0 ≤ x ≤ 0.5) ceramics have been prepared by pressureless sintering at 1973 K to investigate the influence of Nd and Ce co-doping on their electrical conductivity. The electrical conductivity of the ceramics was investigated by impedance spectroscopy measurements from 723 to 1173 K over the frequency range of 20 Hz to 2 MHz in air. The measured values obey the Arrhenius relation. For each composition, the grain conductivity gradually increases with increasing temperature from 723 to 1173 K. At a given temperature, it gradually decreases with increasing neodymium and cerium contents from x = 0 to 0.3; thereafter, the grain conductivity exhibits a slight increase with further increasing neodymium and cerium contents up to x = 0.5.     

Composition dependence of the activation energy of the glass transition in some chalcogenide glasses

The activation energy (E _t) of the glass transition process has been obtained for glassy Se_{80? x} Te₂₀M _x (M = Ag, Cd, In, Sb) and Se_{100? x} M _x (M = In, Te, Sb) systems using differential scanning calorimetry. The composition dependence of E _t is explained in terms of fragility index for the systems. A reversal in the trend of the E _t is explained using topological models.     

Surface tension measurement of undercooled liquid Ni-based multicomponent alloys

The surface tensions of liquid ternary Ni–5%Cu–5%Fe, quaternary Ni–5%Cu–5%Fe–5%Sn and quinary Ni–5%Cu–5%Fe–5%Sn–5%Ge alloys were determined as a function of temperature by the electromagnetic levitation oscillating drop method. The maximum undercoolings obtained in the experiments are 272 (0.15T _L), 349 (0.21T _L) and 363?K (0.22T _L), respectively. For all the three alloys, the surface tension decreases linearly with the rise of temperature. The surface tension values are 1.799, 1.546 and 1.357?N/m at their liquidus temperatures of 1719, 1644 and 1641?K. Their temperature coefficients are ?4.972?×?10^–4, ?5.057?×?10^?4 and ?5.385?×?10^?4?N/m/K. It is revealed that Sn and Ge are much more efficient than Cu and Fe in reducing the surface tension of Ni-based alloys. The addition of Sn can significantly enlarge the maximum undercooling at the same experimental condition. The viscosity of the three undercooled liquid alloys was also derived from the surface tension data.     

Effect of network connectivity on thermal properties of As30Te70– x Tl x glasses

Alternating differential scanning calorimetry (ADSC) studies were undertaken to investigate the effect of Tl addition on the thermal properties of As₃₀Te_{70– x} Tl _x (6?≤?x?≤?22 at%) glasses. These include parameters such as glass-transition temperature (T _g), changes in specific heat capacity (ΔC _p) and relaxation enthalpy (ΔH ^NR) at the glass transition. It was found that T _g of the glasses decreased with the addition of Tl, which is in contrast to the dependence of T _g in As–Te glasses on the addition of Al and In. The change in heat capacity ΔC _p through the glass transition was also found to decrease with increasing Tl content. The addition of Tl to the As–Te matrix may lead to a breaking of As–Te chains and the formation of Tl⁺Te^?AsTe_2/2 dipoles. There was no significant dependence of the change of relaxation enthalpy, through the glass transition, with composition.     

Roughening kinetics of reactively sputter-deposited Ti-Al-N films on Si(100)

The roughening kinetics of Ti_{1? x} Al _x N (0?x? 1) films 600 nm thick synthesized by reactive dc magnetron sputtering on Si(100) substrates has been investigated by atomic force microscopy (AFM). The quantification of surface roughening was achieved by calculation of both vertical root-mean-square roughness and lateral correlation lengths of the film surface using the height-height correction functions of measured AFM images. For all the Ti_{1? x} Al _x N films, a steady roughness exponent α = 0.94 ± 0.03 was determined. The evolution of the surface topography as a function of Al concentration is discussed in terms of the competition between surface diffusion and shadowing instability during sputter deposition.     

Structural analysis of 30RO–30Al2O3–40B2O3 ( R = Mg,Ca or Sr) glasses

Bond-compression and ring-deformation models are used to quantitatively analyze the acoustical properties (elastic moduli, Poisson's ratio, Debye temperature and longitudinal attenuation) of 30RO–30Al₂O₃–40B₂O₃ glasses (in wt%), where R?=?Mg, Ca or Sr. The network structure of the glass is quantified in terms of the four-fold coordinated formers, atomic ring size, cross-link density, first-order stretching force constant and bulk modulus. It is found that network strength increases in the order Mg?>?Ca?> Sr. Structural changes of the glasses are deduced by relating the elastic moduli, the ratio of bond compression to experimental bulk modulus and ultrasonic attenuation to structural parameters and oxygen density.     

Electrical properties of thin films of a-Ga x Te100− x composed of nanoparticles

Thin films of Ga _x Te_{100? x} (x?=?3, 6, 9 and 12) have been synthesized by thermal evaporation. From SEM images, it is observed that all the films contain nanoparticles of sizes varying from 100 to 200?nm. The dc electrical conductivity of the as-deposited films of Ga _x Te_100?x nanoparticles is measured as a function of temperature range from 298 to 383?K, and increases exponentially with temperature. The value of the activation energy, calculated from the slope of ln?σ _dc versus 1000/T plots, is found to decrease with increase in the Ga content. On the basis of the value of the pre-exponential factor σ _o, it is suggested that the conduction is due to thermally assisted tunneling of carriers in localized states near the band edges. The optical measurements suggest an indirect optical band gap in this system. The value of the optical band gap decreases on increasing the Ga concentration.     

Microstructural development during transient directional solidification of a hypomonotectic Al–In alloy

Upward directional non-steady-state solidification experiments have been performed on a hypomonotectic Al–5.5?wt%In alloy. The alloy developed cellular as-solidified microstructure for tip growth rates, V _L, higher than 0.95?mm/s. The casting regions associated with V _L?<?0.95?mm/s were shown to be characterized by a microstructure formed by In droplets disseminated in the Al matrix. Tip growth rate and microstructural features, such as cell spacing and interphase spacing, have been experimentally determined. The experimental cell spacings have been compared with theoretical predictions furnished by the Hunt–Lu model. It was found that the experimental scatter lies below the minimum range of values theoretically predicted. Moreover, the experimental cell spacing evolution with V _L is characterized by a ?1.1 power law. The droplets’ interphase spacing, λ, is related to the growth rate by the Jackson–Hunt relationship (λ ² V _L?=?constant).     

Morphological and magnetic response of copper-substituted nickel ferrite nanoparticles

Ferrite nanoparticles are interesting materials owing to their unique physical and chemical properties. The metal-doped ferrites have well-defined structures and magnetic response, such as high permeability for a specific frequency range. In this study, copper-substituted nickel ferrite (Ni_1?xCu_xFe₂O₄) nanoparticles with a compositional range of 0?≤?x?≤?0.3 were synthesised through a co-precipitation technique. Metal chlorides were used as precursors and NaOH as a precipitating agent for the growth of ferrite nanoparticles. To minimise the internal stresses and maximise the magnetic response, ferrite nanoparticles were annealed in a furnace at 700°C for 6 h. The structural and magnetic response of Ni_1?xCu_xFe₂O₄ ferrite with different values of x were investigated using Scanning Electron Microscopy (SEM), Fourier Transform Infrared spectroscopy (FT-IR), Vibrating Sample Magnetometer (VSM) and X-ray Diffraction (XRD) techniques. XRD analysis confirmed the formation of cubic spinel structure of single phase for all the compositions. The lattice constant decreased with increase in the value of x. FT-IR study showed two main metal oxygen bonds in the range 500–700 cm^?1 confirming the formation of a single-phase cubic inverse structure of Cu-substituted Ni ferrite. VSM results revealed the formation of ferrimagnetic nanoparticles. The optical and magnetic response of the ferrite nanoparticles changed with Cu content.     

Strain rate response of a Ni–Ti shape memory alloy after hydrogen charging

In this work, we investigate the susceptibility of Ni–Ti superelastic wires to the strain rates during tensile testing after hydrogen charging. Cathodic hydrogen charging is performed at a current density of 10?A/m² during 2–12?h in 0.9% NaCl solution and aged for 24?h at room temperature. Specimens underwent one cycle of loading-unloading reaching a stress value of 700 MPa. During loading, strain rates from 10^?6 to 5?×?10^?2?^?s^?1 have been achieved. After 8?h of hydrogen charging, an embrittlement has been detected in the tensile strain rate range of 10^?6 to 10^?4?s^?1. In contrast, no embrittlement has been detected for strain rates of 10^?3?s^?1 and higher. However, after 12?h of hydrogen charging and 24?h of annealing at room temperature, the embrittlement occurs in the beginning of the austenite-martensite transformation for all the studied strain rate values. These results show that for a range of critical amounts of diffused hydrogen, the embrittlement of the Ni–Ti superelastic alloy strongly depends on the strain rate during the tensile test. Moreover, it has been shown that this embrittlement occurs for low values of strain rates rather than the higher ones. This behaviour is attributed to the interaction between the diffused hydrogen and growth of the martensitic domain.     

Crossover from bulk to surface diffusion in the fluctuations of step edges on Pt(111)

Using low-energy electron microscopy we explore the fluctuations of step edges on Pt(111) in the temperature range 1190?K<T<1520?K. Below 1400?K the relaxation times vary with wave vector q as q ³, and above 1400?K as q ², while the observed activation energy changes from 1.25 to 2.75?eV. A discussion shows that surface diffusion is responsible for the rates at low temperatures, and that bulk vacancy diffusion becomes dominant above 1400?K. We infer that a similar crossover must occur for steps on most metal surfaces. The step stiffness is determined as 175 ± 20?meV?nm^?1 at 1500?K.     

The association of Big Five personality traits and religiosity on Internet addiction among Israeli-Palestinian Muslim college students in Israel

ABSTRACT

Prior studies have demonstrated that personality traits and religiosity may be protective/risk factors for the development of Internet addiction; however, these associations have not been examined among the unique population of Israeli-Palestinian young adults. This study was the first to investigate the relationships between Internet addiction (Internet Addiction Test; IAT) with the Big Five personality traits (Big Five Personality Trait Short Questionnaire; BFPTSQ) and religiosity (Positions Regarding Religion Questionnaire) among a sample of Israeli-Palestinian Muslim college students (n?=?350). IAT scores were positively associated with BFPTSQ openness (r?=?.33, p?<?.01), BFPTSQ extraversion (r?=?.30, p?<?.01), and BFPTSQ agreeableness (r?=?.36, p?<?.01), whereas IAT scores were negatively related to religiosity (r?=??.46, p?<?.01), BFPTSQ conscientiousness (r?=??.33, p?<?.01), and BFPTSQ emotional stability (r?=??.36, p?<?.01). The present work may provide insight into risk factors for developing Internet addiction in a manner that may increase early identification and intervention efforts.     

The Impact of Integrated Behavioral Healthcare on Glycemic Control

Integrated behavioral healthcare (IBH) is the “standard of care” to address psychosocial factors impacting diabetes outcomes; it is not standard in practice. This longitudinal, retrospective, chart-review examines IBH impact on glycemic control in an adult diabetes clinic. Adults (n?=?374) with?≥?1 behavioral health encounter,?≥?2 hemoglobin A1c (HbA1c) values, and HbA1c value?>?8% at initial IBH visit were included. Mixed effects linear piecewise models examined differences in slope trajectories for 365 days pre- and post-IBH intervention. Pre-intervention slope was not significant (z?=?? 1.09, p?=?0.28). The post-intervention slope was significant (z?=?? 6.44, p?<?0.001), indicating a significant linear decrease in HbA1c values. Results demonstrated that prior to engaging with behavioral health, there was no change in HbA1c. After initial IBH visit, there was a predicted reduction of?>?1% in HbA1c over the following year. These results suggest that IBH significantly improves patients’ metabolic status. Next steps for IBH research are offered.

     

Dendrite growth velocity in the undercooled melt of glass forming Ni50Zr50 compound

Glass-forming Ni₅₀Zr₅₀ intermetallic compound is containerless undercooled and solidified using electrostatic levitation. Large undercoolings up to ?T = 300 K are achieved. The dendrite growth velocity of the congruently melting alloy is measured as a function of undercooling using a high-speed camera technique. The experimental data is analysed within a sharp interface theory. It is found that the driving force of crystallisation is controlling the growth kinetics at ?T < 250 K but at larger undercoolings the growth kinetics is progressively controlled by atomic diffusion. This leads to a slowing down of the growth velocity. The maximum velocity and the temperature at which the maximum occurs (T_max) are inferred from the dendrite growth velocity – undercooling relation. The relation of the temperature T_max and the glass temperature fits into a general classification scheme for glass-forming systems. The kinetic and thermal undercooling terms are calculated within dendrite growth theory as a function of the total undercooling. At ?T > 126 K, the kinetic undercooling dominates and increases rapidly with the undercooling ?T. The maximum prefactor of the kinetic undercooling is plotted vs. the reciprocal temperature. Its temperature dependence is discussed.     

Distancing oneself from God: relationships with borderline personality symptomatology

Self-harm behaviour traditionally has been associated with borderline personality disorder. In this study, we examined the relationship between borderline personality symptomatology and intentionally distancing oneself from God as self-punishment, based on the assumption that such self-punishment may represent a form of self-harm behaviour. Data from four previous samples of primary care outpatients collected over a two-year period were combined (N?=?1511). Borderline personality was assessed with two measures: the borderline personality scale of the Personality Diagnostic Questionnaire-4 (PDQ-4) and the Self-Harm Inventory (SHI). Point-biserial correlation coefficients revealed that those who endorsed distancing oneself from God as punishment scored relatively higher on both the PDQ-4 (r?=?0.40, p?<?0.001) and the SHI (r?=?0.46, p?<?0.001). Similarly, when compared to respondents who denied ever having distanced themselves from God as punishment, those who did were more likely to exceed the clinical cut-off score on the PDQ-4 (47.3% vs. 10.9%, X^{2 ?}=?152.53, p?<?0.001) and the SHI (57.3% vs. 11.4%, X^{2 ?}=?224.12, p?<?0.001). Findings support our hypothesis that distancing oneself from God as punishment may be a form of self-harm behaviour associated with borderline personality symptomatology.     

Some counterexamples in multidimensional scaling

Given a set X with elements x, y,… which has a partial order < on the pairs of the Cartesian product X², one may seek a distance function ? on such pairs (x, y) which satisfies ?(x₁, y₁) < ?(x₂, y₂) precisely when (x₁, y₁) < (x₂, y₂), and even demand a metric space (X, ?) with some such compatible ? which has an isometric imbedding into a finite-dimensional Euclidean space or a separable Hilbert space. We exhibit here systems (X, <) which cannot meet the latter demand. The space of real m-tuples (ξ₁,…,ξ_m) with either the “city-block” norm Σ_i ∥ξ_i∥ or the “dominance” norm max_i, ∥ξ_i∥ cannot possibly become a subset of any finite-dimensional Euclidean space. The set of real sequences (ξ₁, ξ₂,…) with finitely many nonzero elements and the supremum norm sup_i, ∥ξ_i∥ cannot even become a subset of any separable Hilbert space.     

Type D personality and social relations in adults with diabetes: results from diabetes MILES – The Netherlands

Abstract

Objective: To examine whether individual differences in Type D personality (combination of negative affectivity (NA) and social inhibition (SI)) could explain heterogeneity in perceived social support and relationship adjustment (intimate partner relationship) among people living with diabetes.

Design: In the Diabetes MILES—The Netherlands survey, 621 adults with type 1 or type 2 diabetes (54% female, age: 56?±?14 years) completed measures of Type D personality (DS14), perceived social support and relationship adjustment. We used established DS14 cut-off scores to indicate Type D personality, high NA only, high SI only and reference groups.

Results: Participants from the Type D and NA only groups perceived lower levels of social support (Welch[3,259]?=?37.27, p?<?0.001), and relationship adjustment (Welch[3,191]?=?14.74; p?<?0.01) than those from the SI only and reference groups. Type D was associated with lower social support (lowest quartile; adjusted OR?=?8.73; 95%CI?=?5.05?～?15.09; p?<?0.001) and lower relationship adjustment (lowest quartile; adjusted OR?=?3.70; 95%CI?=?2.10?～?6.53; p?<?0.001). Type D was also associated with increased levels of loneliness.

Conclusion: Participants with Type D and participants with high NA only tend to experience less social support and less relationship adjustment. Type D personality was also associated with more loneliness. Experiencing lower social support and relationship adjustment may complicate coping and self-management in people with diabetes.