70 research outputs found

    Percutaneous screw fixation for trapezium fracture

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    Isolated trapezial fracture is a rare diagnosis which can lead to long term symptoms if missed. We report a case of vertical intra-articular displaced trapezial fracture treated with percutaneous cancellous screw fixation with good functional outcome

    Real Time QRS Detection Based on M-ary Likelihood Ratio Test on the DFT Coefficients

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    This paper shows an adaptive statistical test for QRS detection of electrocardiography (ECG) signals. The method is based on a M-ary generalized likelihood ratio test (LRT) defined over a multiple observation window in the Fourier domain. The motivations for proposing another detection algorithm based on maximum a posteriori (MAP) estimation are found in the high complexity of the signal model proposed in previous approaches which i) makes them computationally unfeasible or not intended for real time applications such as intensive care monitoring and (ii) in which the parameter selection conditions the overall performance. In this sense, we propose an alternative model based on the independent Gaussian properties of the Discrete Fourier Transform (DFT) coefficients, which allows to define a simplified MAP probability function. In addition, the proposed approach defines an adaptive MAP statistical test in which a global hypothesis is defined on particular hypotheses of the multiple observation window. In this sense, the observation interval is modeled as a discontinuous transmission discrete-time stochastic process avoiding the inclusion of parameters that constraint the morphology of the QRS complexes.This work has received research funding from the Spanish government (www.micinn.es) under project TEC2012 34306 (DiagnoSIS, Diagnosis by means of Statistical Intelligent Systems, 70K€) and projects P09-TIC-4530 (300K€) and P11-TIC-7103 (156K€) from the Andalusian government (http://www.juntadeandalucia.es/organismo​s/economiainnovacioncienciayempleo.html)

    Anaerobic digestion of screenings for biogas recovery

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    Screenings comprise untreatable solid materials that have found their way into the sewer. They are removed during preliminary treatment at the inlet work of any wastewater treatment process using a unit operation termed as a screen and at present are disposed of to landfill. These materials, if not removed, will damage mechanical equipment due to its heterogeneity and reduce overall treatment process, reliability and effectiveness. That is why this material is retained and prevented from entering the treatment system before finally being disposed of. The amount of biodegradable organic matter in screenings often exceeds the upper limit and emits a significant amount of greenhouse gases during biodegradation on landfill. Nutrient release can cause a serious problem of eutrophication phenomena in receiving waters and a deterioration of water quality. Disposal of screenings on landfill also can cause odour problem due to putrescible nature of some of the solid material. In view of the high organic content of screenings, anaerobic digestion method may not only offer the potential for energy recovery but also nutrient. In this study, the anaerobic digestion was performed for 30,days, at controlled pH and temperature, using different dry solids concentrations of screenings to study the potential of biogas recovery in the form of methane. It was found screenings have physical characteristics of 30% total solids and 93% volatile solids, suggesting screenings are a type of waste with high dry solids and organic contents. Consistent pH around pH 6.22 indicates anaerobic digestion of screenings needs minimum pH correction. The biomethane potential tests demonstrated screenings were amenable to anaerobic digestion with methane yield of 355,m3/kg VS, which is comparable to the previous results. This study shows that anaerobic digestion is not only beneficial for waste treatment but also to turn waste into useful resources

    Nitrogen precursor effects in iron-nitrogen-carbon oxygen reduction catalysts

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    Metal-nitrogen-carbon (MNC) cathode catalysts were synthesized using nitrogen precursors of varying NitrogenCarbon (NC) ratio by pyrolysis in a constant volume reaction vessel. Here, we demonstrate that increasing a key property, the NC ratio of the nitrogen precursor increased the accessible active site density by reducing carbon deposition in the pores of the carbon support during pyrolysis. The most active catalysts were obtained in this work using melamine, having a NC ratio of 2. Kinetic current density as high as 13 A cm-3 at 0.8 ViR-free and over 100 h of stable current at 0.5 V were observed with melamine based MNC catalysts. \ua9 2011 The Electrochemical Society.Peer reviewed: YesNRC publication: Ye

    Influence of PVP template on the formation of porous TiO2 nanofibers by electrospinning technique for dye-sensitized solar cell

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    The porous TiO2 nanofibers were prepared by electrospinning technique using polyvinylpyrrolidone (PVP) as template as well as pore-forming agent at the calcination temperature of 475 A degrees C for 5 h. The influence of various concentrations of PVP (5, 8 and 10 wt%) on the surface area and porosity of the prepared TiO2 nanofibers (NFs) were studied by using BET-specific surface area analyzer. The TiO2 NFs obtained by using 5 wt% of PVP had higher surface area and porosity than those obtained by using 8 and 10 wt% of PVP. The prepared electrospun TiO2 NFs were characterized by using TG analysis, X-ray diffraction, FTIR, FE-SEM and TEM studies. Finally, dye-sensitized solar cells were assembled using the prepared TiO2 NFs as the photoanode, Pt as the cathode and 0.5 M 1-butyl-3-methylimidazolium iodide, 0.5 M LiI, 0.05 M I-2, 0.5 M 4-tertbutylpyridine in acetonitrile as an electrolyte. Among the three photoanodes, the cell assembled using porous TiO2 NFs obtained by using 5 wt% of PVP showed higher power conversion efficiency (PCE) of 4.81 % than those obtained by using 8 and 10 wt% of PVP, which showed the lower PCE of 4.13 and 3.42 %, respectively

    Tuning the mechanical and thermal properties of (MgNiCoCuZn)O by intelligent control of cooling rates

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    The possibility of altering the phase equilibria of multicomponent oxide systems through precise control of configurational entropy has opened a platform with unlimited possibilities to fine-tune material properties. The current work is aimed at tailoring the mechanical and thermal properties of (MgNiCoCuZn)O by an intelligent design of constituent phase structure resulting from controlled cooling from the stabilization temperature. Based on the cooling rates, the amount of CuO nucleation was found to vary between 5.4 and 12.3 wt%, along with a corresponding decrease in Cu2+ content in the matrix. It was observed that with the decrease in Cu2+ ion concentration in the matrix, the Young's modulus and hardness increased by 33% and 26%, respectively, along with a corresponding decrease in the coefficient of thermal expansion by 15%. Similarly, an increased nucleation of CuO precipitates led to the improvement of fracture toughness of the material by 15%, while its thermal conductivity remained unaltered
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