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A linear ramp stimulus is generally preferred to accurately measure the non-linearity errors in an analog to digital converter (ADC). Three methods are proposed to generate a linear ramp signal, of which the first approach employs two sine waves. In contrast, the second utilizes a sine wave with a pulse signal to generate a parabolic signal which is then differentiated to produce a ramp signal. The third method achieves linearity by maintaining a constant potential across the resistor to push a constant current into the capacitor. The three proposed concepts have been designed and simulated to compute the differential non-linearity (DNL) error for an ideal 8 bit ADC in 90 nm CMOS technology. The third method shows high linearity when compared to the existing methods, by exhibiting a very low DNL error of 0.0015 LSB in simulation. Its implementation indicates that 92% of the silicon area is reduced, making it suitable for ADC testing. [ABSTRACT FROM AUTHOR]

Integration of the latest technological advancements such as Internet of Things (IoT) and Computational Intelligence (CI) techniques is an active research area for various industrial applications. The rapid urbanization and exponential growth of vehicles has led to crowded traffic in cities. The deployment of IoT infrastructures for building smart and intelligent traffic management system greatly improves the quality and comfort of city dwellers. This work aims at building a cost effective IoT enabled traffic forecasting system using deep learning techniques. The case study experimentation is done in a real time traffic environment. The main contributions of this work include: (i) deploying road side sensor station built with ultrasonic sensor and Arduino Uno controller for obtaining traffic flow data (ii) building an IoT cloud system based on open source Thingspeak cloud platform for monitoring real time traffic (iii) performing short term traffic forecast using Recurrent Neural Network (RNN) models such as Long Short Term Memory (LSTM) and Gated Recurrent Unit (GRU). The performance of the prediction model is compared with the traditional statistical methods such as Autoregressive Integrated Moving Average (ARIMA), Seasonal ARIMA (SARIMA) and Convolutional Neural Network (CNN). The results show good performance metrics with RMSE of 5.8, 7.9, 10.2 for LSTM model and 6.7, 8.6, 10.9 for GRU model for three different scenarios such as whole day, morning congested hour and evening congested hour datasets. [ABSTRACT FROM AUTHOR]

Autonomous transportation is a new paradigm of an Industry 5.0 cyber-physical system that provides a lot of opportunities in smart logistics applications. The safety and reliability of deep learning-driven systems are still a question under research. The safety of an autonomous guided vehicle is dependent on the proper selection of sensors and the transmission of reflex data. Several academics worked on sensor-based difficulties by developing a sensor correction system and fine-tuning algorithms to regulate the system's efficiency and precision. In this paper, the introduction of vision sensor and its scene terrain classification using a deep learning algorithm is performed with proposed datasets during sensor failure conditions. The proposed classification technique is to identify the mobile robot obstacle and obstacle-free path for smart logistic vehicle application. To analyze the information from the acquired image datasets, the proposed classification algorithm employs segmentation techniques. The analysis of proposed dataset is validated with U-shaped convolutional network (U-Net) architecture and region-based convolutional neural network (Mask R-CNN) architecture model. Based on the results, the selection of 1400 raw image datasets is trained and validated using semantic segmentation classifier models. For various terrain dataset clusters, the Mask R-CNN classifier model method has the highest model accuracy of 93%, that is, 23% higher than the U-Net classifier model algorithm, which has the lowest model accuracy nearly 70%. As a result, the suggested Mask R-CNN technique has a significant potential of being used in autonomous vehicle applications. [ABSTRACT FROM AUTHOR]

Polymers are the long chain organic materials that are held together by directional covalent bonds. These kind of organic materials are either synthesized or naturally obtained and they have wide range of application in the medical field due to its physical properties, chemical properties and multifarious processing technique. For the past two decade, these polymers were used to produce variety of medical devices and implants by laser sintering. Since laser based additive manufacturing technique was a thermal process, there may be a change in the material property after sintering and which may affect the usage of the polymer in medical field. This work presented here aims to investigate the material property of biocompatible eos PA12 polymer powder and a laser sintered part. The Scanning Electron Microscope (SEM) with Energy Dispersive Spectroscopy (EDAX), Fourier Transform Infrared Spectroscopy (FT-IR), X-Ray Diffraction (XRD) and Differential Scanning Calorimeter (DSC) analysis were carried out to investigate the properties. The experimental investigation carried out in order to get insight into laser-material interaction and the corresponding results indicated that the laser energy influences the material properties of polyamide powder. [ABSTRACT FROM AUTHOR]

The right-half-plane (RHP) zero in a continuous conduction mode boost converter results in a significantly restricted closed-loop bandwidth (BW) for higher voltage gain and/or load current conditions. A compensating ramp is used for current-mode control (CMC), and a higher ramp slope degrades the BW. Variable-frequency digital CMC offers inherent current-loop stability and real-time tuning scope for higher closed-loop BW. However, the challenges are to select the sampling frequency and sampling instant of the output voltage with discontinuous ripple due to the effective series resistance of the output capacitor, and its impact on stability. This paper shows that an event-based current-mode constant off-time digital modulator achieves superior stability and performance in a boost converter along with the reduced RHP zero effect over other digital CMC techniques. Using a discrete-time framework, the fast-scale stability conditions and small-signal models are analytically derived for various digital CMC techniques, which are validated using SIMPLIS simulation. A boost converter prototype is tested, and the analytical predictions are verified experimentally. Further, the analysis is extended to a non-inverting buck–boost converter. [ABSTRACT FROM AUTHOR]

Ripple-based constant on-time and off-time control techniques can achieve fast step-down and step-up transient performance along with an improved light-load efficiency. However, they suffer from varying switching frequency at the steady state and often require a phase-locked loop for frequency regulation. This paper proposes a constant on/off-time hybrid modulation technique in a digitally current-mode controlled synchronous buck converter. The proposed technique considers an event-based sampling mechanism using one sample per switching cycle, which makes it useful for high-frequency implementation. This requires a monoshot timer and a digital voltage controller $G_c(z)$. The proposed technique can be configured to a constant on-time or off-time modulator with seamless transition because of sharing $G_c(z)$ ; thus, improved step-up/down transient performance can be retained. Furthermore, a discrete-time framework is proposed for fast-scale stability analysis, and the effects of finite sampling and practical parasitics are discussed. Discrete-time small-signal models are derived for the direct digital control design with enhanced stability and performance. A frequency adaptation method is discussed to customize the switching frequency in real time. A buck converter prototype is tested, and the usefulness of the proposed modulation technique is verified experimentally. [ABSTRACT FROM AUTHOR]

This paper reviews the background phenomenon of various cloaking techniques such as transformation optics, transmission line network, microwave network cloak, scattering cancellation techniques in the applications of antenna field particularly in hiding the obstacle from the electromagnetic source and reducing the mutual coupling between two antennas that was placed closed to each other. Cloaking at multiple frequencies in each cloaking techniques are also compared. The comparative study showed that the scattering cancellation technique based on aperiodic Frequency Selective Surfaces (FSS) structure will dominate the electromagnetic cloaking field in near future. [ABSTRACT FROM AUTHOR]

Polyamides 12 (PA-12) has an application in the medical field such as suture materials, scaffolds for tissue engineering and for various medical devices fabrication. More often the medical devices which are produced using PA-12 are addressed to be a bioinert and osseointegration with the host tissue will be in the slower rate. This experimental work aims to improve osseointegration of PA-12 by depositing a layer of bioactive material over the surface, since the surface is the first portion to interact with host tissue. Hydroxyapatite (HA) is a calcium phosphate similar to the human tissue in morphology and composition also it is well known bioactive material. This material has been synthesised by wet chemical precipitation process and deposited over polyamide substrate using Electron Beam Deposition (EBD). Various characterization studies have been carried out on coating and Human Osteosarcoma cells MG-63 were seeded on the coated sample to study its viability. The results revealed that Hydroxyapatite layer was deposited successfully over the PA-12. The coated layer some agglomeration of particles. The cell possesses 92.3% of viability, which may significantly improve the biocompatibility of prostheses and medical devices. [ABSTRACT FROM AUTHOR]

We present an estimation of the electron density modulation index ( $\frac{\delta{N_{\mathrm{e}}}}{N_{\mathrm{e}}}$ ) for the first time using solar type IIIb radio burst observations. The mean value of $\frac{\delta{N_{\mathrm {e}}}}{N_{\mathrm{e}}}$ is calculated to be ${\approx}\,0.006\pm0.002$ over the heliocentric distance range $r \approx1.6\,\mbox{--}\,2.2~\text{R}_{\odot}$ . The estimated $\frac {\delta{N_{\mathrm{e}}}}{N_{\mathrm{e}}}$ shows a power law dependence on $r$ with a power law index ${\approx}\,0.31\pm0.10$ . The wavenumber ( $k$ ) spectrum for the electron density fluctuation $({\frac{\delta{N_{\mathrm{e}}}}{N_{\mathrm {e}}}})^{2}$ values shows a Kolmogorov-like behavior. Using $\frac{\delta{N_{\mathrm{e}}}}{N_{\mathrm{e}}}$ and the Kolmogorov turbulence index, we estimated the amplitude of density turbulence [ $C_{n}^{2}{(r)}$ ] in the aforementioned range of $r$ . [ABSTRACT FROM AUTHOR]

We present rare contemporaneous low-frequency ( $< 100~\mbox{MHz}$) imaging, spectral, and polarimetric observations of a moving type IV radio burst that had close spatio-temporal association with a white-light coronal mass ejection (CME) near the Sun. We estimate the electron density near the burst region from white-light coronagraph polarized brightness (pB) images of the CME as well as the two-dimensional radio imaging observations of the thermal free-free emission at a typical radio frequency such as 80 MHz. We analyze the burst properties such as the degree of circular polarization, the spectral index, and fine structures using the radio polarimeter and the radio spectral observations. The obtained results suggest that second harmonic plasma emission from the enhanced electron density in the leading edge of the CME is the cause of the radio burst. We determine the strength of the coronal magnetic field ( $B$) for the first time based on this interpretation. The estimated value ( $B \approx 1$ gauss) in the CME leading edge at a heliocentric distance of $\approx 2.2~R_{\odot }$ agrees well with the similar $B$ values reported earlier based on other types of observations. [ABSTRACT FROM AUTHOR]

We report ground-based radio spectral and polarimeter observations of two successive split-band Type-II bursts that occurred on 20 February 2014 at low frequencies ( ${<}\,100~\mbox{MHz}$) in association with a solar coronal mass ejection (CME). The temporal interval between the onset of the two bursts was very small, ≈ one minute. Both of the bursts exhibited fundamental-harmonic structure. The coronal magnetic-field strength [ $B$] in the upstream region of the associated magnetohydrodynamic (MHD) shock, estimated from the split-band observations, is in the range $B \approx1.3\,\mbox{--}\,1.1~\mbox{G}$ over the radial distance [ $r$] interval $r \approx1.49\,\mbox{--}\,1.58~\mbox{R}_{\odot}$ for the first Type-II burst, and $B \approx1.3\,\mbox{--}\,1.0~\mbox{G}$ over $r \approx1.49\,\mbox{--}\,1.64~\mbox{R}_{\odot}$ for the second Type-II burst. Based on the results obtained, we show that the first and the second Type-II bursts in the present case were likely due to MHD shocks generated by the near-simultaneous interaction of two different regions of the aforementioned CME with a preceding CME and a pre-existing coronal streamer. [ABSTRACT FROM AUTHOR]

ABSTRACT The fatigue strain-life equation is in general applicable to isotropic materials. It was recently attempted to account for material anisotropy because of crystallographic texture in fatigue modelling. The proposed modification was limited to isotropic hardening. The present work is an extension of the previous work, wherein a general framework to model anisotropy using phenomenological yield criterion and anisotropic hardening is provided. Yld2004-18p yield criterion and the so-called homogenous anisotropic hardening model are used to demonstrate the anisotropic cyclic behaviour of low carbon steel. The proposed methodology can be utilized in applications including multiaxial fatigue modelling. [ABSTRACT FROM AUTHOR]

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]

The effect of a lithium salt on the general polymer dynamics of poly(ethylene oxide) (PEO) and how these dynamical alterations affect the ionic conductivity and structural relaxations in (PEO)4:LiClO4 have been investigated. The study was based on differential scanning calorimetry (DSC) and dielectric relaxation studies. The DSC studies indicated an increased glass transition temperature of (PEO)4:LiClO4 as compared to that of PEO. The polymer-salt complex exhibited enhanced conductivity of σD.C. =3.2×10−7 S·cm−1 at room temperature (298K) due to the presence of mobile Li+ ions. Impedance data have been scaled and analyzed under conductivity and modulus formalisms over wide ranges of frequency and temperature for both PEO and (PEO)4:LiClO4. For PEO, the analysis of the scaled formalisms indicates that both the conductivity and the structural relaxation mechanisms are temperature-independent above the melting point of PEO. However, below the melting point, the nucleation and growth of spherulites and also the formation of ‘interphase’ regions in PEO result in a hindered long range D.C. conductivity, which, in turn, leads to a decoupling of the D.C. conductivity and the structural relaxation. However, for (PEO)4:LiClO4, by comparing the conductivity relaxation data with the calorimetric glass transition and analysis of scaled formalisms, a direct coupling between Li+ ion motions and polymer segmental dynamics is observed for the polymer electrolyte. [ABSTRACT FROM AUTHOR]

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]

66.7Li2O–33.3P2O5 mol% glass prepared by twin-roller rapid quenching has been chosen to investigate the nucleation and crystallization kinetics using differential scanning calorimetry (DSC), scanning electron microscopy (SEM) and high temperature X-ray diffraction (XRD) as the experimental tools. Such studies assume importance in designing materials for solid state ionic devices. The glass exhibits a nucleation rate of 3.1×1018 m−3 s−1 at a typical temperature of 583K and crystal growth rate of 2.1×10−2 nms−1 at 643K. Non-isothermal DSC studies reveal that the glass undergoes bulk crystallization with an activation energy of 114kJmol−1. The crystallized phase is identified as lithium pyrophosphate (Li4P2O7). Crystallization kinetic studies reveal that Li4P2O7 crystallizes three dimensionally with increasing number of nuclei. Interestingly, lithium metaphosphate (LiPO3) appears as a secondary phase in the glass matrix, however, the final glass ceramic product obtained after prolonged heat treatment of the glass is single phase Li4P2O7. The secondary phase also grows three dimensionally with an activation energy of 365kJmol−1, but with constant number of nuclei in contrast to Li4P2O7. The high nucleation and growth rate with lower activation energy for crystallization of Li4P2O7 underscore that the glass is extremely prone to nucleation and crystallization. [ABSTRACT FROM AUTHOR]

Abstract: This review article presents a brief overview of synthesis and application aspects of fast fluoride ion conducting materials in the field of Solid State Ionics. Possible synthesis methodologies known in the literature for the preparation of various fluoride materials have been outlined. Further, their transport characteristics with respect to their crystal structure have been discussed. Various approaches influencing their ionic conductivity value in the light of synthesis methodology, composition, dopant concentration, crystallite size, microstructure etc. have been reviewed. At the end, possible technological applications of fast fluoride ion conducting materials in different solid state ionic devices have been presented. [Copyright &y& Elsevier]

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: (PEO)4:LiClO4 and the effect of δ-Al2O3 nano-fillers on the polymer electrolyte have been investigated by differential scanning calorimetry (DSC) and dielectric relaxation studies. The DSC studies indicated a decrease in the glass transition temperature of (PEO)4:LiClO4 in the presence of fillers. The polymer–salt complex exhibited a conductivity of σ D.C. =4.0×10−7 Scm−1 at room temperature (298K). In the presence of 4wt% δ-Al2O3 fillers, the ionic conductivity increased by almost two orders of magnitude and exhibited a value of σ D.C. =1.5×10−5 Scm−1 (298K). By comparing the conductivity data with the calorimetric glass transition it is evident that the enhanced conductivity can be attributed to a speeding up of the segmental polymer dynamics. Hence, the combined data indicate a direct coupling between Li+ ion motions and polymer segmental dynamics, even when 4wt% nano-fillers have been introduced. From the temperature dependence of the conductivity relaxation time, which, thus, is coupled to the structural (α) relaxation time, it is understood that the fragility of the polymer electrolytes decreases with increasing filler concentration. The decrease in T g and fragility suggests that the interaction between the nano-fillers and polymer is mainly non-attractive in nature. Moreover, the dielectric relaxation studies show that the β-relaxation speeds up with increasing concentration of filler particles. However, this speeding up is probably of less importance for the ionic conductivity. It was also found that the activation energy of the β-relaxation of PEO decreases in the presence of δ-Al2O3 nano-fillers and lithium salt. The strength of the β-relaxation increases also in the presence of salt ions. The γ-relaxation seems to be unaffected by the salt and fillers. [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]

Machine vision is a computer vision system that enables a computer to work on image-based inspection and analysis for different applications. In this computer vision, a camera and sensor were used to view an image for its analysis with the help of some sort of algorithms, then processed to infer the image-based data. Machine vision systems along with Python programs can be used for many interdisciplinary applications like weld inspection, online monitoring in manufacturing auto components etc. In this study, the "Edge detection python algorithm" was developed and run through "Google Colab" notebook to inspect the edges and the boundaries of samples like faying surface-modified friction welded dissimilar joints and a binder clip (paper clamp) to check any defects or cracks and straightness etc. With the help of this Python algorithm, the edge detection was done by Sobel, Scharr, and Prewit operators. An input image of the weld joint and the binder clip were converted into Otsu's binary threshold image. The matrix vision camera and the CMOS sensor were used in the machine vision set-up to take the images. This written algorithm is helpful to trace the edges of any kind of solids components. The edges of the binder clips and the weld joint/zone were detected. The binder clips were inspected under two different cases namely the clip in folding condition (Case I) and the binder clip in unfolding condition (Case II). The results showed a defect that was identified in the weld zone and no bending was in the binder clips. This kind of study is useful in manufacturing industries for quality inspection purposes with a new machine vision set up for online inspection of fabricated components like nuts and bolts etc. [ABSTRACT FROM AUTHOR]

ABSTRACT The fatigue behaviour of cold rolled and annealed sheet metals are influenced by the anisotropy of mechanical properties due to crystallographic texture. However, the existing fatigue strain-life models are primarily meant for isotropic material behaviour. In the present work, the Coffin-Manson equation for strain-life is modified to include the effect of anisotropy using phenomenological plasticity models. It is observed that the variation of strain hardening exponent is critical to model the strain-life behaviour. Variation of strain hardening exponent with orientation is modelled using existing anisotropic yield criteria. The prediction of fatigue life using the proposed model correlates well with the experimental results of Al6061-T6 along different orientations. The proposed model can be used to predict the fatigue properties along any orientation from the fatigue data along one orientation and monotonic mechanical properties along longitudinal, transverse and diagonal directions. [ABSTRACT FROM AUTHOR]

Abstract: Crystallization kinetic studies of Li+ ion conducting mol% 60Li2O–40P2O5 glass indicate a 2-dimensional crystal growth mechanism as compared to the 3-dimensional growth mechanism for LiPO3 glass (mol% 50Li2O–50P2O5). Spectroscopic studies reveal that the structures of these two glass compositions differ considerably resulting in different mechanisms for crystal growth. Isothermal ionic conductivity studies further support 2-dimensional crystallization in mol% 60Li2O–40P2O5 glass. Above the glass transition temperature the ionic conductivity deviates from the usual Arrhenian temperature dependence due to the additional effect of the movement of the phosphate polymeric chains in the glass network. The ionic conductivity of the glass ceramic corresponding to the mol% 60Li2O–40P2O5 glass behaves in an Arrhenian fashion with an activation energy of 1.21eV, much higher than that of 0.77eV for the glass. Further, it is established using canonical scaling that the mechanism for ionic conduction is temperature independent. [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: Crystallization kinetics of bulk and pulverized glass samples of the system mol% 50Na2O:50P2O5 have been investigated through isothermal as well as non-isothermal DSC studies. Analysis of the crystallization exotherms reveals that the bulk sodium metaphosphate glass undergoes single-stage crystallization with an order parameter (Avrami constant) of 2.7±0.1 and an activation energy for crystallization equal to 142.5kJ/mol, suggesting internal (bulk) crystallization of the glass. The activation energy for structural relaxation, evaluated by the analysis of the dependence of T g on different heating rates, turns out to be 534.8kJ/mol. The exotherm peaks of pulverized glasses exhibit a shift in the crystallization temperature, T c along with a change in the height and width of the peak. The pulverized glass sample undergoes surface crystallization, with almost the same value of activation energy for crystallization as that of bulk glass. The single-stage crystallization mechanism of sodium metaphosphate (bulk and pulverized) glass is closely associated with Johnson–Mehl–Avrami (JMA) 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]

This paper presents a novel Time Tick based Built In Self Test (TT BIST) for measuring the static errors of an Analog to Digital Converter (ADC). The proposed method determines the period elapsed during transition between two consecutive digital levels and compares it with the ideal period of transition. A counter that works, at higher speed relative to the sampling rate of the ADC under test, is used. It counts the number of time ticks occurred during every transition. The required ramp signal is generated dynamically, using current source with digital switch for selecting the equivalent test signal. Further to support testing of errors in ratiometric ADC, a slope conditioning module is also implemented. The entire computation cycle is done in a single ramp cycle whereas in conventional histogram method multiple waveforms are required. Thus, the proposed TT method requires less time to achieve desired accuracy levels by choosing the appropriate slope of the ramp signal. [ABSTRACT FROM AUTHOR]

A normal lithium ion conductor, lithium metaphosphate has been taken up for transport studies, as it has enabled for investigation of the Li+ ion transport in (i) crystalline form as LiPO3, (ii) crystalline LiPO3 heterogeneously doped with inert oxide inclusion and homogeneously doped with aliovalent cations, (iii) glassy form as mol% 50Li2O:50P2O5, synthesized by melt-quenching process and (iv) newly identified polymer-metal salt complex (PEO)6:LiPO3. All the above materials have been characterized through XRD, DSC, SEM, Raman spectroscopy and impedance spectroscopy techniques. [ABSTRACT FROM AUTHOR]

Objective: Medium-chain fatty acids (MCFAs) have been reported to be less obesogenic than long-chain fatty acids (LCFAs); however, relatively little is known regarding their effect on insulin action. Here, we examined the tissue-specific effects of MCFAs on lipid metabolism and insulin action.Research Design and Methods: C57BL6/J mice and Wistar rats were fed either a low-fat control diet or high-fat diets rich in MCFAs or LCFAs for 4-5 weeks, and markers of mitochondrial oxidative capacity, lipid levels, and insulin action were measured.Results: Mice fed the MCFA diet displayed reduced adiposity and better glucose tolerance than LCFA-fed animals. In skeletal muscle, triglyceride levels were increased by the LCFA diet (77%, P < 0.01) but remained at low-fat diet control levels in the MCFA-fed animals. The LCFA diet increased (20-50%, P < 0.05) markers of mitochondrial metabolism in muscle compared with low-fat diet-fed controls; however; the increase in oxidative capacity was substantially greater in MCFA-fed animals (50-140% versus low-fat-fed controls, P < 0.01). The MCFA diet induced a greater accumulation of liver triglycerides than the LCFA diet, likely due to an upregulation of several lipogenic enzymes. In rats, isocaloric feeding of MCFA or LCFA high-fat diets induced hepatic insulin resistance to a similar degree; however, insulin action was preserved at the level of low-fat diet-fed controls in muscle and adipose from MCFA-fed animals.Conclusions: MCFAs reduce adiposity and preserve insulin action in muscle and adipose, despite inducing steatosis and insulin resistance in the liver. Dietary supplementation with MCFAs may therefore be beneficial for preventing obesity and peripheral insulin resistance. [ABSTRACT FROM AUTHOR]

Abstract: The conduction characteristics of SnF2 from room temperature (300K) to 463K have been investigated by using impedance spectroscopy. The temperature dependent conductivity plot shows a break in conductivity around 443K corresponding to the α→γ phase transition temperature. The electrical properties of SnF2 are also investigated by extracting dielectric and modulus data from impedance values. The frequency dependent plots of M″ and Z″ show that the conductivity relaxation is non-Debye in nature. The activation energy responsible for relaxation has been calculated from the modulus spectra and is found to be almost the same as that from the temperature dependent dc conductivity data. The real part of conductivity and permittivity in addition to the modulus spectra of the present system show scaling behavior, which means σ′(ω), ɛ′(ω) and M′(ω) isotherms successfully collapse to a single master curve indicating that the relaxation mechanism is temperature independent. Different scaling approaches have been applied to arrive at a correlation between the scaling parameters. [Copyright &y& Elsevier]

Abstract: Sodium pentafluorodistannite has been synthesized through high-energy ball milling as well as by solid-state reaction method and characterized through XRD and DSC techniques. The electrical conductivity and modulus characteristics of the system are investigated in the temperature range from 373K to 473K by means of impedance spectroscopy. The conductivity of the ball-milled sample is about one order of magnitude higher compared to the sample prepared by solid-state reaction method. The frequency dependent conductivity of the present system shows the power law feature. The real part of dielectric permittivity shows a huge value at lower frequencies due to the presence of space charge polarization. The activation energy responsible for relaxation calculated from the modulus spectra is found to be almost the same as the value obtained from temperature variation of dc conductivity. The conductivity and modulus spectra of the present system show scaling behavior, which means that σ*(ω) and M″(ω) isotherms successfully collapse to a single master curve indicating temperature independent relaxation behavior. [Copyright &y& Elsevier]

Abstract: This paper focuses on material optimization by reduction in raw material size for sheet metal components. Panel roof, an automobile component is chosen for analysis. Using a commercial explicit solver, the sheet metal-forming process is analysed. To represent the actual tool profile in the analysis, computer-aided design (CAD) model of the tool geometry is developed by scanning the die in coordinate measuring machine (CMM). Forming limit diagram (FLD) and percentage reduction in thickness are checked in the finite element analysis (FEA). Experimental verification of the optimized blank is done by circular grid analysis technique. Difference in major strain varies from 2 to 10% and difference in minor strain varies from 0 to 6%. Weight savings of about 1.57% is achieved in the current work. [Copyright &y& Elsevier]

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]

A comparative investigation on Li+ ion transport has been carried out in various phases of lithium metaphosphate such as (i) crystalline LiPO3, (ii) glassy form as mol % 50Li2O-50P2O5, synthesized by melt-quenching process, (iii) single phase glass-ceramic LiPO3 obtained through controlled heat treatment of mol % 50Li2O-50P2O5 and (iv) newly identified polymer-metal salt complex (PEO)6: LiPO3. All of the above materials have been characterized through XRD, DSC, optical microscopy and impedance spectroscopy techniques. The Li+ ions, migrating with an activation energy value of 1.4 eV through “interstitial mechanism” in polycrystalline LiPO3, exhibited a dc conductivity value of 2.5×10-8 Scm-1 at 280 °C. The above conductivity value was enhanced by four orders of magnitude in Li2O-P2O5 glass, with an activation energy value of 0.72 eV. The glass subjected to controlled heat treatment devitrified into single phase glass-ceramic, as revealed by XRD and optical microscopy studies. The glass-ceramic exhibited better conduction characteristics compared to polycrystalline LiPO3. Polycrystalline LiPO3, complexed with polymer PEO has exhibited a conductivity value of 3.1×10-7 Scm-1 at 78 °C with activation energies of 0.21 and 0.88 eV for Li+ ion migration above and below the softening point of the polymer, respectively. [ABSTRACT FROM AUTHOR]

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]

Abstract: Sodium borophosphate glasses of composition (mol%) 50Na2O–50[xB2O3–(1-x)P2O5], 0≤x≤0.8 have been prepared by melt quenching method and characterized through XRD, DSC, FTIR and impedance spectroscopy techniques. The glass transition temperature increases with the substitution of B2O3 due to the cross-linking of the network and the FTIR study shows the presence of different structural units in the network. The ionic conductivity study as a function of composition of B2O3 shows increment in conductivity with two conductivity maxima at 10 and 30mol% of B2O3 and conductivity variations with temperature follow an Arrhenius type behaviour. Transport numbers evaluated for ions and electrons show that Na+ ions are the mobile species in the investigated systems. The frequency dependence of the electric conductivity follows a simple power law feature. The analysis of various electrical parameters as a function of temperature in different complex planes shows that the charge transport occurs by the hopping mechanism. [Copyright &y& Elsevier]

Abstract: Solid polymer electrolyte thin films based on poly(ethylene oxide) (PEO) complexed with NaNO3 salt with compositions between 2 and 10 ether oxygens per sodium have been prepared using the solution cast method as a possible sodium ion-conducting polymer electrolyte system. The complexation of the films has been investigated through X-ray diffraction (XRD), differential scanning calorimetry (DSC), and Fourier transform infrared spectroscopy (FTIR) measurements. Electrical properties have been measured as a function of composition and temperature using complex impedance spectroscopy. The maximum ionic conductivity has been found to be ∼3.5×10−6 S/cm at room temperature for the composition O/Na=3:1. The transference numbers of different mobile species have been determined by means of DC polarization and combined AC/DC techniques. The complex impedance data have been analysed in conductivity and permittivity formalisms to cast light on possible ion transport mechanisms. The peaks found in the electric modulus plot have been characterized in terms of the stretched exponential parameter. [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]

Focuses on a study on the use of Poisson-based methods for ground water detection monitoring at Resource Conservation and Recovery Act solid and hazardous waste facilities. Role of the United States Environmental Protection Agency (EPA) and the American Society for Testing and Materials (ASTM); Exploration of Poisson-based methods on counts of analytical hits and actual concentration measurements; Conclusions.

Abstract: SnF2 of various crystallite sizes have been obtained by mechanical milling. Further, the crystallite size dependent conduction characteristics of SnF2 have been investigated by X-Ray Diffraction, High Resolution Scanning Electron Microscopy and Impedance Spectroscopy techniques. The crystallite size and microstrain developed during the milling process have been calculated by using Scherrer''s semi-empirical formula. Further, an attempt is made to correlate the conductivity results of mechanically milled samples with the crystallite size and microstrain. In all cases, the temperature dependent conductivity plot obeys the Arrhenius behavior. The enhancement in conductivity of SnF2 is found to be of two orders of magnitude after simply milling for 10h. [Copyright &y& Elsevier]

In the present paper, impedance measurements of the battery configuration, Anode│lithium borophosphate glass electrolyte│LiCoO2 cathode, has been carried out to throw some light on the electrochemical interfacial behavior between the chosen electrodes and electrolyte. The cathode material, lithium cobalt oxide (LiCoO2) has been prepared by three different techniques and characterized. Sol-gel synthesized LiCoO2 showed uniformly distributed spherical shape particles with an average size of 500 nm and also exhibited better electrochemical performance. Charging and discharging (2–3 cycles) of the battery indicated an OCV of 2 V. However, the theoretical OCV of 4 V could not be achieved. The poor performance of the battery could be attributed to the electrochemical processes and SEI film formation at the electrode/electrolyte interfaces. Impedance spectroscopy shows that the major contributions to the impedance of the battery are the electrolyte resistance and the electrode/electrolyte interfacial resistance. With each recharging cycle, the value of electrolyte resistance remains almost constant; however, the interface resistance increases, during the passage of current, due to the interfacial passive layer formation. [ABSTRACT FROM AUTHOR]