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Abstract: The main aim of the present study is to investigate the effect of second glass modifier Na2O on the crystallization kinetics and thermal stability of the mol% xNa2O:(50−x)Li2O:50P2O5 glasses, where Li+ ions are progressively substituted with Na+ ions, using differential scanning calorimetry. The DSC studies showed the classical ‘mixed alkali effect’ on the glass transition temperature, with the Tg minima for the glass composition of [Na+/(Li++Na+)]=0.5 i.e. x =25mol%. The crystallization temperature decreases as Na+ ions completely replaces Li+ ions. The presence of small concentration of second alkali (either the guest ion or host ion) tends to enhance the thermal stability, S, against devitrification as observed for 5≤ x ≤15 and 37.5≤ x ≤45. The ‘mixed alkali effect’ tends to thermally stabilize the intermediate compositions of mol% xNa2O:(50−x)Li2O:50P2O5 as these compositions exhibited high S parameter, high activation energy for crystallization and low enthalpy of crystallization, ΔHc. [Copyright &y& Elsevier]

Abstract: Background: The number of citations of a paper gives an indication of an article's merit and importance within a medical specialty. We identify and analyse the 100 most cited papers in foot and ankle surgery. Method: The Science Citation Index Expanded was searched for citations in 15 respected journals containing foot and ankle articles. Papers were analysed for subject, authorship, institution, country and year of publication. The average yearly citation was compared to total number of citations. Results: 3501 foot and ankle papers were returned. The maximum number of citations was 1084 and the mean was 104. The top 100 papers were published between 1979 and 2007, with the majority published in the last decade. The ankle was the most important anatomical region discussed, and basic science and degenerative disease were popular topics. We found a large discrepancy between the total number of citations with average yearly citation. Conclusion: Foot and ankle surgery is a young and rapidly developing sub-specialty within orthopaedics. Recently there has been a significant increase in influential papers published. Certain topics are popular indicating their importance within the field. This study highlights important papers in foot and ankle surgery giving an insight into readership. [Copyright &y& Elsevier]

Highlights: [•] Influence of stress relaxation in ductility not reported before. [•] Plausible mechanism of stress relaxation explained. [•] Stress drop during relaxation vary with strain, unlike reported results. [•] Stress drop is due to strain aging effect by martensite in DP and TRIP steel. [ABSTRACT FROM AUTHOR]

Abstract: Thermal, structural and ionic conduction characteristics of lithium niobophosphate glass (mol% 50Li2O–45P2O5–5Nb2O5) are reported and compared with the characteristics of lithium metaphosphate glass (mol% 50Li2O–50P2O5). The presence of the second glass former (Nb2O5) not only improves the chemical durability and thermal stability but also enhances the conduction characteristics of lithium metaphosphate glass. The ionic conductivity measurements are reported in the extended temperature range i.e. above the glass transition temperature (Tg) where a non-Arrhenius temperature dependence of the ionic conductivity has been observed. The ion conduction process below Tg is governed by a well-defined activation energy whereas the conduction process above Tg is activated by at least two different phenomena discussed in the light of the structural relaxation and crystallization. [Copyright &y& Elsevier]

Abstract: The ionic conductivity of Sn(1−x)K x F(2−x) systems has been investigated as a function of composition and temperature using complex impedance spectroscopy. These materials have been prepared by normal solid state reaction method and characterized through XRD and DSC. The highest conducting sample has been prepared through mechanochemical synthesis technique in addition to solid state reaction method. The universal scaling behavior of the real and imaginary part of the impedance including complex impedance plots indicating temperature independent relaxation behavior has been demonstrated. This result is further supported by the scaling behavior of the real part of the conductivity. [Copyright &y& Elsevier]

Abstract: Commonly used fatigue crack growth prediction models estimate life in a deterministic manner. Realizing that several variables influence fatigue crack growth, it is pertinent to assess crack growth using probabilistic models. In the present work, a probabilistic model is studied using continuous and segmented crack growth rate data models. It is observed that the prediction of life using Paris constants from continuous data model is accurate only in a finite region of the crack growth. The model based on segmented data provides more accurate life predictions with lesser variance with experimental data than the continuous data model. [Copyright &y& Elsevier]

Abstract: An intercalation compound with composition Na0.7CoO2 has been synthesized through different preparative techniques such as solid state reaction, ball milling and sol gel techniques. The investigation reveals that the cathode material with an average particle size of about 500nm of uniform morphology can be synthesized through sol gel technique. Further, this synthesis technique improves the stoichiometry of the sodium content significantly. The electrical resistivity of these cathode materials is found to be in the range of 4 to 12mΩ-cm at 300K. It has been observed that, the resistivity of the cathode material increases with increase in sodium content. The electrochemical cells with the configuration Na | [wt.% 0.3 PEO-0.7 PEG]6:NaPO3 |composite cathode material, have shown an open circuit voltage (OCV) value of 2.7V. The (OCV) of the cells with the cathode prepared by sol–gel and ball milling route has shown a plateau region of about 40h, when compared to the plateau region of 10h for the battery with the cathode prepared by solid state reaction. The reduction in the particle size of the cathode material has improved the stability of the electrode electrolyte interface and thereby discharges characteristics. [Copyright &y& Elsevier]

Abstract: Background: The incidence of venous thromboembolism (VTE) is unknown in elective foot and ankle surgery. The National Institute for Health and Clinical Excellence (NICE) recently published guidelines on reducing the risk of venous thromboembolism in surgical patients. This includes patients undergoing elective foot and ankle surgery. Method: In March 2010 we surveyed the current practice in VTE prophylaxis in elective foot and ankle surgery amongst members of the British Orthopaedic Foot and Ankle Society (BOFAS). Results: The response rate was 84 (53%). The total number of elective foot and ankle operations performed by the surveyed group was 33,500 per annum. The estimated incidence of DVT, PE and fatal PE was 0.6%, 0.1% and 0.02%. In our study the number of patients needed to treat to prevent a single fatal PE is 10,000 although this figure is open to important bias. Conclusion: We question the applicability of the NICE guidelines to patients undergoing elective foot and ankle surgery. We consider that this data justifies the prospective study of the incidence of VTE in patients undergoing elective foot and ankle surgery, without the use of chemical thromboprophylaxis. [Copyright &y& Elsevier]

Abstract: The high performance fluoride ion conductor BaSnF4 has been prepared by a simple precipitation in addition to both solid state reaction and mechanochemical synthesis techniques. XRD results indicate that the material BaSnF4 obtained by all the methods crystallizes with the same tetragonal structure (P4/nmm). The crystallite size and morphology of the BaSnF4 particles determined by XRD and FE-SEM show a variation with respect to different methods of preparation. The transport properties of BaSnF4 have been investigated by impedance spectroscopy and the results show that the conductivity values are closely related to the crystallite size and micro-strain. The transport number measurement and NMR studies further confirm that the increase in conductivity is due to fluoride ions. The scaling result of complex impedance plots shows that the dynamical process occurring at various frequencies are independent of temperature. [Copyright &y& Elsevier]

Abstract: Experimental determination of strain–fatigue life curve is expensive considering the time and effort involved. Several empirical relations based on monotonic tensile properties and/or hardness is available for estimating strain–fatigue life properties. Existing criteria to evaluate the accuracy of these empirical relations are limited by the data points in the strain–fatigue life curve. A new criterion based on the prediction errors of fatigue constants is proposed to overcome the limitation. Around eight prediction methods are evaluated for two hundred twenty-six steel grades from literature using the existing and the proposed criteria. It is observed that the conclusions from the new criterion are more reliable than the existing criteria. [ABSTRACT FROM AUTHOR]

Abstract: Investigations on the glass system mol% 50Li2O:(50− x)P2O5:xB2O3 reveal that the glass forming region is limited to a small region of 0≤ x ≤20. Addition of B2O3 is found to enhance the thermal stability of the glasses. Raman spectra reveal that the glass matrix undergoes structural modification for x ≥15, with the formation of borophosphate structural units, due to the presence of which, the glass composition 50Li2O: 30P2O5: 20B2O3 has exhibited dc conductivity value of 1.8×10−5 S cm−1, when compared to the value of 8.4×10−7 S cm−1 of 50Li2O: 50P2O5 at 110 °C. Though ball milled sample for x =15 initially exhibited better conduction characteristics than melt quenched ones, the conductivity decreased during thermal cycling process probably due to the phase instability of the milled samples. The frequency dependent conductivity plots have been scaled to a single master curve indicating temperature independent relaxation mechanism. [Copyright &y& Elsevier]

Abstract: Sodium metaphosphate-based glasses (mol%) (100− x) NaPO3–xNa2SO4 (0≤ x ≤25), were prepared by melt quenching technique. The influence of Na2SO4 additives on the thermal, physical and structural properties has been interpreted using density, DSC, ultrasonic velocity and FTIR data. The linear decrease in glass transition temperature (T g) with increase in Na2SO4 content indicates decrease in average chain length of the host glass matrix. FTIR data has revealed that Na2SO4 has depolymerized the phosphate glass matrix. The temperature-dependent conductivity data of the above glass samples have been obtained using impedance measurement in the temperature range 400–510K. The σT products for all the glass compositions have obeyed an Arrehenius relationship, exhibiting an activation energy of about 0.70eV for ion migration. The ionic conductivity of the host glass, NaPO3 with a value of 1.1×10−6 Scm−1 has been enhanced by one order of magnitude to a value of 9.4×10−6 Scm−1 for the glass with maximum content of Na2SO4 at 450K. Enhancement in the ionic conductivity has been explained on the basis of dissociation of Na2SO4, resulting in the enhancement of the charge carrier concentration. Electronic transport number of a value 0.01 determined by the dc polarization technique and ionic transport number of a value 0.94 measured by the emf method indicate the ionic nature of the conducting species. [Copyright &y& Elsevier]

Abstract: Conduction characteristics of the poly(ethylene oxide) based new polymer electrolyte (PEO)6:NaPO3, plasticized with poly(ethylene glycol) are investigated. Free standing flexible electrolyte films of composition (PEO)6:NaPO3 + x wt.%PEG400 (30⩽ x ⩽70) are prepared by solution casting method. A combination of X-ray diffraction (XRD), optical microscopy and differential scanning calorimetry (DSC) studies have indicated enhancement in the amorphous phase of polymer due to the addition of plasticizer. Further, a reduction in the glass transition temperature observed from the DSC result has inferred increase in the flexibility of the polymer chains. The cationic transport number of 0.42 determined through combined ac–dc technique has confirmed ionic nature of conducting species. Ionic conductivity studies are carried out as a function of composition and temperature using complex impedance spectroscopy. The electrolyte with maximum PEG400 content has exhibited an enhancement in the conductivity of about two orders of magnitude compared to the host polymer electrolyte. The complex impedance data is analyzed in conductivity, permittivity and electric modulus formalism in order to throw light on transport mechanism. A solid state electrochemical cell based on the above polymer electrolyte with a configuration Na|SPE|(I2 +acetylene black+PEO) has exhibited an open circuit voltage of 2.94V. The discharge characteristics are found to be satisfactory as a laboratory cell. [Copyright &y& Elsevier]

Abstract: The aim of this study was to assess and compare intrinsic forefoot function and pliability of the forefoot in selected cohorts of shoe wearing and barefoot populations. Measurements on the right foot of randomly selected 100 non-shoe wearing (Indians) and 100 shoe wearing (British) groups were carried out. Both groups were matched for age, sex and body mass index, and had not previously suffered foot problems. Using a force gauge, the force of extension and flexion of the great toe, adduction between the first and second toe and abduction at fifth metatarsophalangeal joint was measured. The length and width of the weight bearing and non-weight bearing feet in these groups was compared using a Pliability ratio. Using the Student t-test at 95% confidence interval, there was no statistically significant difference in the intrinsic forefoot muscle function. Multivariate regression analysis showed that after adjustment for other variables like gender and ethnicity, the shod status had a significant influence on the pliability ratio. This study showed that although shoe wearing does not affect the intrinsic forefoot muscle strength, it appeared to result in stiffer forefeet. This difference is more marked in women (p =0.008) as compared to men (p =0.0171). Shoe wearing can affect the transmission of forces during locomotion. This can be both in the dynamic and the static settings. Most shoes have an inbuilt medial arch support and toe boxes that are narrower than the true width of forefeet wearing them. This may result in incomplete accommodation of the dynamic correlates of the transverse and longitudinal arches of the foot leading to stiffer feet that may have a negative influence on their functional capability. [Copyright &y& Elsevier]

Abstract: A new Na+ ion conducting polymer electrolyte, based on poly(ethylene oxide) (PEO) and sodium meta phosphate (NaPO3) is investigated. (PEO) n :NaPO3 polymer metal salt complexes with different [ethylene oxide]/Na ratios (n =3, 4, 6, 8 and 10) are prepared by the solution casting method. Dissolution of the salt into the polymer host is confirmed by X-ray diffraction, differential scanning calorimetry (DSC) and scanning electron microscopy. Further, interaction of the polymer chains with the metal salt is substantiated by Fourier transform infrared spectroscopy. The electrical conductivity of the samples is measured over the temperature range 322–351K. The temperature dependent conductivity exhibits two different activation energies, below and above the softening point of the polymer. The composition (PEO)6:NaPO3 is found to exhibit the least crystallinity but the highest conductivity 2.8×10−8 Scm−1 at 351K. The electronic transport number, measured by the dc polarization technique, shows that the conducting species are ionic in nature. The effect of ethylene carbonate on the best conducting composition is investigated by DSC and impedance spectroscopy. The addition of 20wt.% ethylene carbonate, increases the amorphous phase and enhances the conductivity by two orders of magnitude. [Copyright &y& Elsevier]

Abstract: The electrical conductivity of NaNO3–xAl2O3 composites has been studied over the wide range of temperature and frequency by means of impedance spectroscopy. The real part of the frequency dependent conductivity exhibits a simple power law feature and the dimensionless frequency exponent n has been determined. The conductivity spectra show scaling behaviour when the conductivity spectra are scaled by σ dc T, where T is temperature in Kelvin. The real part of dielectric permittivity shows saturation at higher frequencies and a strong dispersion at lower frequencies. The imaginary part of permittivity varies inversely with frequency, due to the presence of dc conductivity. The frequency dependent plots of M″ and Z″ show that the conductivity relaxation is non-Debye in nature. The Kohlrausch-Williams-Watts stretched exponential function was used to describe the modulus spectra and the stretching exponent β is found to be temperature independent. The conductivity relaxation time has been estimated from the modulus spectra. The activation energy responsible for relaxation has been evaluated and it was found to be almost same as that of dc conductivity. [Copyright &y& Elsevier]

The composite solid electrolytes, NaNO3 dispersed with Al2O3, CeO2, ZrO2 and SiO2 have been prepared by melt quenching method and investigated through XRD, DSC and electrical conductivity techniques. Typical increase in conductivity is about two orders of magnitude for 10 mol% of Al2O3 at 200 °C. The electronic transference number evaluated through dc polarization method was found out to be 1×10−2 at 200 °C. The dependence of conductivity on concentration of dispersoids and particle size is in accordance with the space charge theory of conduction. The enhanced conductivity of NaNO3 homogenously doped by Ca(NO3)2 was further enhanced by heterogeneous doping of Al2O3. By the contribution of these doping processes, the conductivity is enhanced by three orders of magnitude at 200 °C. The experimental and theoretically calculated values of conductivity using Maier''s space charge layer model are in reasonable agreement. [Copyright &y& Elsevier]

In the present study, the evidence of complex dislocation band formation in pure Mg has been reported. The transmission electron microscopy investigation suggests that the double cross-slip of < c + a > screw dislocations plays an important role in the evolution of dislocation structure within these bands. The existence of dislocation bands is explained on the basis of instability of slip on a basal slip system, which results in sudden propagation of slip on pyramidal planes. [ABSTRACT FROM AUTHOR]