3,250 research outputs found

    "Test me and treat me" - attitudes to vitamin D deficiency and supplementation: a qualitative study

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    © 2015 BMJ Open, "Test me and treat me"-attitudes to vitamin D deficiency and supplementation: a qualitative study. This manuscript version is made available under the Creative Commons Attribution Licens

    Biodiesel Performance within Internal Combustion Engine Fuel System: A Review

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    This review paper highlights the tribological performance of biodiesel at contacting surfaces in the fuel delivery system of compression ignition (diesel) engines. The focus is on the injection components that include low and high pressure injection pumps, diesel fuel injectors, electro-hydraulic valves, diesel fuel lubricity measurements and effects of biodiesel on the running conditions in a diesel fuel injection system. The common rail system and the distributor pump injection systems with electronic diesel control are among the modern trends that are specifically highlighted. Boundary, mixed and hydrodynamic lubrication regimes together with lubricant oil film thickness, pressure and engine performance are also considere

    Ultrasonic Waves Assisted Synthesis of Curcuminoids Based on 3-Methylacetylacetone and in Situ Synthesis of Gold Nanoparticles Capped with Curcuminoids

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    Ultrasonic irradiation was used to induce the Knuevenagle reaction between aromatic aldehydes and 3-methylacetylacetone to synthesize curcumin analogues with moderate to good yields. The structures of the compounds were established by elemental analysis and from their mass and 1HNMR spectra. In situ curcumin-gold nanoparticles were synthesized. The solutions of the prepared nanoparticles have purple to deep-red colors and their UV-vis spectra were characterized by the Surface Plasmon Resonance bands within the range 538-554 nanometer

    Characterization of the geomagnetic H-component for a paired station in Africa

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    This scientific research investigates the quiet days variation, Sq(H) of H- component of geomagnetic field for the paired stations: Aswan (ASW: G.G.Lat.24.090N, G.G.Lon.32.890E and G.M.Lat.15.200, G.M.Lon.104.240),Durban (DRB: G.G.Lat.29.860S, G.G.Lon.31.020E and G.M.Lat.39.210, G.M.Lon.96.10) located along the 960 MM (magnetic meridian) using the ten international quietest days’ geomagnetic data from MAGDAS for the year 2009 (a low activity year).The study reveals that sq(H) shows predominantly the diurnal, monthly and seasonal variations of the geomagnetic H-component during the quiet days year round. With maximum amplitude of sq(H) in ASW and minimum in DRB. Meanwhile, the CEJ seen as negative depressions in the H-component of earth field at DRB are all salient physical processes in this study. Further data analysis also revealed many other interesting characteristics for the Sq(H) over African sector paired station. The conclusion drawn from the study shows that the geomagnetic field variations in the northern hemisphere are higher due to solar activities in the region. The Northern Hemisphere is tilted toward the sun, so this area of the Earth receives more direct sunlight during the day than the Southern Hemisphere does. The Southern Hemisphere, on the other hand, is tilted away from the sun and thus receives the sun's rays at an angle, which significantly explains why there is a consistent decrease when it reaches the Durban station (southern hemisphere station), hence the solar activity of the sun influences the Earth’s magnetic field, and the upper atmosphere(ionosphere)

    Caspian Sea level fluctuation and determination of setback line

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    In the past 25 years, rising of the Caspian Sea level, part of a natural treat to the sea, has inundated and destroyed many buildings and arable lands and threatened many inhabitations in coastal areas. The main reason for these damages is that the law-setback has lost its efficiency and human activities have proceeded seaward. The goal of this study is to introduce a proper setback line for the southern coast of Caspian Sea on the basis of critical water elevation and the results of coastal vulnerability assessment to sea level rise. This setback contains vertical and horizontal buffers. The Coastal vulnerability index (CVI) method is used for coastal vulnerability assessment and is also used in the Geographic Information System. Five variables in two sub-indices were used in this method. The final map obtained from coastal vulnerability assessment divided the coastal zone into low, moderate, high and very high risk categories based on quartile ranges and visual inspection of data. A mean distance of very high risk category of vulnerability map from a second vertical buffer in each rural district was then proposed as a width of horizontal buffer in the same rural district

    Mode NASA blade used to calculate the power generator for (VAWT) by drag and lift coefficients

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    One of the confrontations with increasing demand on power in the entire world the methodologies of provided power divided into traditional methods against renewable methods. This article presents a simulation model to estimate the integrated power from vertical access wind turbine (VAWT) stages of development of a simulation model of local power supply system (LPSS) with (VAWT). However, wind power is one of the quickest developing advances for the sustainable power age. Disturbingly, in the ongoing years a few instances of corruption on telecommunication systems frameworks have emerged because of the presence of wind ranches, and costly and in fact complex restorative estimations needed. The grade of variation of power verified according to the grid size. The parameters were taken in the study through the preparation of the model are (efficiency, cost, and system response) compared to the benefits against disadvantages when combining the two systems to achieve a high performance of the power stability

    Enhanced Heartbeat Graph for emerging event detection on Twitter using time series networks

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    © 2019 Elsevier Ltd With increasing popularity of social media, Twitter has become one of the leading platforms to report events in real-time. Detecting events from Twitter stream requires complex techniques. Event-related trending topics consist of a group of words which successfully detect and identify events. Event detection techniques must be scalable and robust, so that they can deal with the huge volume and noise associated with social media. Existing event detection methods mostly rely on burstiness, mainly the frequency of words and their co-occurrences. However, burstiness sometimes dominates other relevant details in the data which could be equally significant. Besides, the topological and temporal relationships in the data are often ignored. In this work, we propose a novel graph-based approach, called the Enhanced Heartbeat Graph (EHG), which detects events efficiently. EHG suppresses dominating topics in the subsequent data stream, after their first detection. Experimental results on three real-world datasets (i.e., Football Association Challenge Cup Final, Super Tuesday, and the US Election 2012) show superior performance of the proposed approach in comparison to the state-of-the-art techniques

    Comparative Analysis of Natural Radioactivity Content in Tiles made in Nigeria and Imported Tiles from China

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    In this investigation, natural radioactive contents in tiles manufactured in Nigeria and tiles imported from China were measured using gamma ray spectroscopy. High Purity Germanium detector was used to estimate the concentrations of some radioisotopes present in 17 samples of various tiles from Nigeria and China. The average activity concentrations of 226Ra, 232Th, and 40K for the tiles were found to be 68.2 ± 0.5; 173.9 ± 9.2 and 490 ± 15 Bq/kg and 58.2 ± 0.5, 161.5 ± 9.4 and 455.7 ± 15.1 Bq/kg for the tiles from Nigeria and China respectively. Radiological hazard indices such as absorbed dose rate, radium equivalent activity, external Hazard Index (Hex), internal Hazard Index (Hin), Annual Effective Dose (mSv/y), Gamma activity Index (Iγ) and Alpha Index (Iα) were determined for both kind of tiles from Nigeria and China. The mean values obtained were: 354.56 and 317.16 Bq/kg; 169.22 nGyh−1 and 153.92 nGyh−1; 0.95 and 0.87; 1.14 and 1.08; 1.59 mSv/y and 1.52 mSv/y; 1 and 1.15 and; 0.34 and 0.29 respectively. The mean value of radium equivalent obtained in this study is less than that of the international reference value of 370 Bq/kg for the both kind of tiles

    Comparative Analysis of Natural Radioactivity Content in Tiles made in Nigeria and Imported Tiles from China

    Get PDF
    In this investigation, natural radioactive contents in tiles manufactured in Nigeria and tiles imported from China were measured using gamma ray spectroscopy. High Purity Germanium detector was used to estimate the concentrations of some radioisotopes present in 17 samples of various tiles from Nigeria and China. The average activity concentrations of 226Ra, 232Th, and 40K for the tiles were found to be 68.2 ± 0.5; 173.9 ± 9.2 and 490 ± 15 Bq/kg and 58.2 ± 0.5, 161.5 ± 9.4 and 455.7 ± 15.1 Bq/kg for the tiles from Nigeria and China respectively. Radiological hazard indices such as absorbed dose rate, radium equivalent activity, external Hazard Index (Hex), internal Hazard Index (Hin), Annual Effective Dose (mSv/y), Gamma activity Index (Iγ) and Alpha Index (Iα) were determined for both kind of tiles from Nigeria and China. The mean values obtained were: 354.56 and 317.16 Bq/kg; 169.22 nGyh−1 and 153.92 nGyh−1; 0.95 and 0.87; 1.14 and 1.08; 1.59 mSv/y and 1.52 mSv/y; 1 and 1.15 and; 0.34 and 0.29 respectively. The mean value of radium equivalent obtained in this study is less than that of the international reference value of 370 Bq/kg for the both kind of tiles
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