In situ synthesis of hydroxyapatite-grafted titanium nanotube composite

The present study is an investigation to demonstrate the effectiveness of insitu approach in the synthesis of hydroxyapatite-grafted titanium nanotube composite (HA-TNT). This method involves combining the process of HA sol–gel and rapid breakdown anodisation of titanium in a novel solution consisting of NaCl and N3PO4. This new synthesis approach produced a uniform dispersion of Anatase and Rutile phases of TiO2 nanotubes with minimal agglomeration in the matrix of crystalline HA. The characterisation of homogenised HA-TNT composite was investigated via field emission scanning electron microscopy (FESEM), energy dispersive spectroscopy (EDS), transmission electron microscope (TEM) and X-ray diffraction (XRD). FESEM and TEM images indicated the nanostructure of composite with TiO2 nanotube diameter of approximately 10 nm. XRD and EDS analyses confirmed the formation of HA crystalline with the Ca/P ratio of 1.58 and formation of Anatase and Rutile phase of TiO2 nanotubes

Investigation of effect weight of parameters affecting the hydrodynamic coefficients in design of surface-piercing propellers

High speed craft with the wide and various uses of entertainment, sporting, commercial and military, usually has a top speed of 30 knots. Due to the limitations of the design, use of propulsion system is a key issue, with regard to the desirable features surface-piercing propeller, their use in the propulsion system of the vessel, has been very useful. High efficiency, no restrictions to increase the diameter, resistance equipment supplied propeller removed, the proper functioning of cavitation, are examples of these features. To achieve the best efficiency and thrust requirements requires accurate determination of the coefficient of hydrodynamic thrust and torque. Given the importance of determining the coefficients and their dependence on various physical parameters and geometric, it is necessary to understand the effect of these parameters on the hydrodynamic coefficients, so in this study, experimental tests and collect data using sensitivity analysis, the weight of each parameter and the interaction of parameters surface-piercing propeller to evaluate the hydrodynamic coefficients on the propeller thrust, propeller torque, and therefore performance, is desired. Based on the results obtained, the parameters of step angle, skew and compared to other parameters, have the greatest impact in changing the propeller efficiency, while changing the ratio Immersion, the change will have little impact on efficiency and propelle

Perspectives of the Apiaceae Hepatoprotective Effects - A Review

The liver has the crucial role in the regulation of various physiological processes and in the excretion of endogenous waste metabolites and xenobiotics. Liver structure impairment can be caused by various factors including microorganisms, autoimmune diseases, chemicals, alcohol and drugs. The plant kingdom is full of liver protective chemicals such as phenols, coumarins, lignans, essential oils, monoterpenes, carotenoids, glycosides, flavonoids, organic acids, lipids, alkaloids and xanthenes. Apiaceae plants are usually used as a vegetable or as a spice, but their other functional properties are also very important. This review highlights the significance of caraway, dill, cumin, aniseed, fennel, coriander, celery, lovage, angelica, parsley and carrot, which are popular vegetables and spices, but possess hepatoprotective potential. These plants can be used for medicinal applications to patients who suffer from liver damage

Catalytic Upgrading of Biomass Model Compounds: Novel Approaches and Lessons Learnt from Traditional Hydrodeoxygenation – a Review

Catalytic hydrodeoxygenation (HDO) is a fundamental process for bio‐resources upgrading to produce transportation fuels or added value chemicals. The bottleneck of this technology to be implemented at commercial scale is its dependence on high pressure hydrogen, an expensive resource which utilization also poses safety concerns. In this scenario, the development of hydrogen‐free alternatives to facilitate oxygen removal in biomass derived compounds is a major challenge for catalysis science but at the same time it could revolutionize biomass processing technologies. In this review we have analysed several novel approaches, including catalytic transfer hydrogenation (CTH), combined reforming and hydrodeoxygenation, metal hydrolysis and subsequent hydrodeoxygenation along with non‐thermal plasma (NTP) to avoid the supply of external H2. The knowledge accumulated from traditional HDO sets the grounds for catalysts and processes development among the hydrogen alternatives. In this sense, mechanistic aspects for HDO and the proposed alternatives are carefully analysed in this work. Biomass model compounds are selected aiming to provide an in‐depth description of the different processes and stablish solid correlations catalysts composition‐catalytic performance which can be further extrapolated to more complex biomass feedstocks. Moreover, the current challenges and research trends of novel hydrodeoxygenation strategies are also presented aiming to spark inspiration among the broad community of scientists working towards a low carbon society where bio‐resources will play a major role.Financial support for this work was provided by the Department of Chemical and Process Engineering of the University of Surrey and the EPSRC grants EP/J020184/2 and EP/R512904/1 as well as the Royal Society Research Grant RSGR1180353. Authors would also like to acknowledge the Ministerio de Economía, Industriay Competitividad of Spain (Project MAT2013‐45008‐P) and the Chinese Scholarship Council (CSC). LPP also thanks Comunitat Valenciana for her postdoctoral fellow (APOSTD2017)

A study into the effect of loading conditions on the resistance of asymmetric high-speed catamaran based on experimental tests

Preparing high speed and sea keeping simultaneously are outstanding features of Catamaran boats (as one of multi-hull boats). In this paper, influence of loading conditions on drag through 6 series of experimental tests has been investigated. Experiments have been executed in a towing tank for model in scale 1 ratio to 11.43. Ultimately, results have been presented to full scale boat by Froude number and ITTC model. Loading conditions consist primarily of both weight of boat and longitudinal central gravity (LCG). Hence, adopted Catamaran has been examined in various loading conditions (light, full and over load) and two LCGs allocated to each weight in order to clarify effect of ones on drag. According to results whatever central gravity comes close to transom (backward position of LCGs), drag diminishes in high speed but increase in boat weight leads to decrease in its impact. As a consequence, the most descent of drag about 9.6% occurred in light load and maximum speed. Keywords: Catamaran, Load conditions, Towing tank, Dra

Turbulent flow analysis and cavitation prediction in axial cooling water pump

The aim of this literature is to investigate the performance and three-dimensional flow field in an axial flow CW pump and observing cavitation phenomenon in specified situations. Computational Fluid Dynamic software FLUENT 6.3 was utilized to simulate the whole flow field of the pump to capture all features in the domain. RNG k-ε model combined with standard wall functions is used to deal with the turbulent nature of the problem. Two principal domains are verified: 1) the rotor domain which includes four moving impellers. 2) the stator domain which includes nine static vanes. Hence, the rotor-stator interaction was treated with Moving Reference Frame (MRF) technique. Pressure contour and streamlines of the simulation are shown here. The performance curve of the model is in good agreement with the reference power plant data. Finally, the cavitation region defined with the vaporization pressure is demonstrated for cases with different flow rates

An empirical evaluation of the sea depth effects for various wave characteristics on the performance of a point absorber wave energy converter

cited By 5In this paper, the effects of sea depth on the performance of a modified point absorber wave energy converter (WEC) are examined using an experimental study. For experimental evaluation of WEC, the general cubic shape is used. For obtaining the final shape of this novel WEC, 3 stages are considered including, still water depth optimization, optimization of geometrical specifications and shape optimization. The focus of this article is on the first stage. In this context, by creating waves with different amplitudes and periods, evaluation is conducted in three different still water depths. WEC oscillation in the directions of heave, surge and pitch are measured and compared. Furthermore, an appropriate scale for building a full scale WEC for operating in the Caspian Sea environment is studied and proposed. Experimental test results show that increasing the water depth causes an increment on the WEC oscillation on the directions of heave and pitch. However, this process is different in the case of surge oscillations; increasing the depth leads to a reduction in WEC oscillation. The analysis of these results shows that the use of point absorber WEC with the dominant motion of pitch in deep water can provide better conditions for energy extraction. © 2017 Elsevier Lt

Evaluation of the main operating parameters of a homogeneous charge compression ignition engine for performance optimization

Homogeneous charge compression ignition engines require a smart control system to regulate the input quantities of the engine in various operational conditions. Achieving an optimum combustion needs an appropriate system response for different engine loads and speeds according to the power acquired from the engine, as well as the amounts of emissions present in the exhaust. Therefore, performing a set of experimental tests together with numerical simulations in a wide range of conditions facilitates calibration of the input parameters of the engine. In this study, the effects of the thermodynamic parameters and the thermokinetic parameters on the engine output in the preliminary design stage were obtained at different speeds to determine the optimum exhaust emissions, the optimum combustion timing and the ranges of misfiring and knock, using multiple-zone thermodynamic modelling. On the assumption that the simulation cycle is closed, the probability density function was used to determine the initial conditions for the temperature and the residual gas from the previous cycle mass distribution in each area inside the cylinder. The results obtained proved that the kinetic properties of the mixture due to the effects of the the air-to-fuel ratio, the percentage of exhaust gas recirculation and the percentage of reformer gas have dominant effects on the output in comparison with the thermodynamic parameters such as the intake pressure and the intake temperature. At low speeds, exhaust gas recirculation retards combustion and delays engine knock. At higher engine speeds, the reformer gas advances combustion and improves misfiring