48 research outputs found

    Evaluation of Root Canal Morphology and Root Apex Anatomy of Mandibular Premolars in an Iranian Population: an ex-vivo study

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    Objectives Adequate knowledge about canal anatomy is necessary for clinicians to prevent any damage to the periodontium. The aim of this study was to evaluate the canal and apical complexities of the mandibular first and second premolars in an Iranian population.Methods One-hundred mandibular first (n=50) and second (n=50) premolars were collected. After access cavity preparation, 2% methylene blue was injected into the canals, and they were sealed with Coltosol and nail varnish. Next, demineralization and clearing with 5% nitric acid and methyl salicylate were performed. Apical morphology including the presence of accessory canals, apical delta, anastomoses and canal configurations was evaluated under a stereomicroscope at x16 magnification. Descriptive statistics (including tables, central tendency and dispersion tests) were used for data analysis.Results The most prevalent form of canal type was Vertucci’s type I in first and second premolars. The mean distance between the apical foramen and anatomic apex, apical foramen and apical constriction, and apical constriction and anatomic apex was 0.3, 0.6 and 0.9 mm, respectively for the first premolars. These values were 0.3, 0.5 and 0.8 mm, respectively for the second premolars.Conclusion Although most mandibular premolars have one canal, using appropriate cleaning methods is imperative because of high prevalence of accessory canals, anastomoses and apical deltas. First premolars pose more challenges in this respec

    Exploring the best model for sorting Blood orange using ANFIS method

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    OranOrange has abundant nutritional properties and is consumed worldwide.  Sorting oranges of different masses based on their physical traits could help reduce packaging and transportation cost.  The ‘Blood’ cultivar of Iranian oranges from Kermanshah province of Iran (7.03 °E 4.22 °N) was used in this study.  100 samples were randomly selected.  During the two-day experiment, all measurements were carried out inside the laboratory at mean temperature of 24°C.  In this study, some physical properties of ‘Blood’ orange were measured, such as length, width, thickness, volume, mass, mean value of geometric diameter, sphericity and projected area.  ANFIS and linear regression models were employed to predict the mass based on sphericity and mean of projected area inputs.  In ANFIS model, samples were divided into two sets, with 70% for training set and 30% for testing set.  The coefficient of determination (R2) for ANFIS and linear regression models were 0.983 and 0.927, respectively.  It is shown that the mass can be estimated based on ANFIS model better than linear regression model.   Keywords: linear regression, orange, packaging, physical properties, sorting

    Characterization of Siloxane-poly(methyl methacrylate) Hybrid Films Obtained on a Tinplate Substrate Modified by the Addition of Organic and Inorganic Acids

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    Tinplate is used to food packaging and other types of packages. The corrosion resistance of the tinplate has been study due the necessity of an alternative to high environmental impact of chromatization process. Therefore protective coatings as hybrid films base elaborations with different acids are studied to improve the barrier effect against corrosion. The objective of this work is characterize hybrid films deposited on a tinplate from a sol made up of the alkoxide precursors 3-(trimethoxysilylpropyl) methacrylate (TMSM), tetraethoxysilane (TEOS) and poly(methyl methacrylate) (PMMA) together with one of three acids (acetic, hydrochloric or nitric acid) and to verify their action against the corrosion of the substrate. The films were obtained by a dip-coating process and cured for 3 hours at 160 °C. The film hydrophobicity was determined by contact angle measurements, and the morphology was evaluated by SEM. FTIR measurements were performed to characterize the chemical structures of the films. The electrochemical behavior of the coatings was evaluated by techniques open circuit potential monitoring (OCP), potentiodynamic polarization and electrochemical impedance spectroscopy (EIS). The results demonstrate that the siloxane-PMMA films improve the protective properties of the tinplate, with the films obtained by acetic acid addition exhibiting the greatest improvement

    FABRICATION AND CHARACTERIZATION OF POLYANILINE-GRAPHENE COMPOSITE AS ELECTRODE IN ELECTROCHEMICAL CAPACITOR

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    In this study, polyaniline-graphene composites with different nano-structures are synthesized and the behaviour of the obtained composites serving as electrode materials in electrochemical capacitors is studied. The morphology, crystal structure, and thermal stability of the composites are examined using scanning electron microscopy (SEM), X-ray diffraction (XRD), and Thermal gravimetric analysis (TGA). Electrochemical properties are characterized by cyclic voltammetry (CV). According to the results, the obtained composites show different crystal structures and different thermal stabilities, and consequently different electrochemical capacities, when used as electrodes in electrochemical capacitors. A nano-fibre composite is shown to have a good degree of crystallization, 5.17% water content, 637oC degradation onset temperature, and 379 Fg-1 electrochemical capacity
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