Synthesis of Magnetic Mno, Co and Ni Nanoparticle by Oleylamie and Oleic Acid

Magnetic MnO, Co, CoO, and Ni nanoparticles are synthesized by thermal decomposition of metal 2,4-pentanedionates in the presence of oleylamine (OLA), oleic acid (OA), and 1-octadecene (ODE). Similar experimental conditions are used to prepare nanoparticles except for the metal starting materials (manganese 2,4-pentanedionate, nickel 2,4-pentanedionate, and cobalt 2,4-pentanedionate). MnO nanoparticles are always obtained as the reaction is controlled with different temperatures, precursor concentrations, ligand ratios, and reaction time. Only three experimental conditions can produce pure phase CoO and Co nanoparticles. The same three experimental conditions lead to the production of pure phase Ni nanoparticles. Other experimental conditions produce mixture phase nanomaterials. The nanoparticle sizes increase with the increase of reaction temperatures. The influence of reaction precursor concentrations on the sizes of the nanoparticles is also studied. The ratio of ligand OLA to OA is used to control the reaction in terms of nanoparticle sizes. It is observed that the reaction time affects nanoparticle growth. The nanoparticles are studied by XRD, TEM, and magnetic measurements. This work presents a facile method to prepare nanoparticles with different sizes, which provides a fundamental understanding of nanoparticle growth in solution.

Cold atmospheric plasma jet applied for TiO2/carbon fiber composite biomaterial

In the present work, Titanium dioxide (TiO2) micro–nanostructured thin films are deposited by a cold atmospheric plasma jet on carbon fiber substrates. The surface morphology, grain size, and structure phase of TiO2 thin films are investigated by scanning electron microscopic (SEM), X-ray diffraction (XRD), and Raman spectrum. As the discharge voltage increased from 5 to 15 kV, the size of these TiO2 particles decreased from 2 to 3 μm to less than 1 μm. The XRD and Raman spectroscopic results show TiO2 on the carbon fiber surface prepared by atmospheric plasma jet is at the mixture phase of anatase and rutile. We also investigated the adhesion and proliferation assays of MC3T3-E1 preosteoblasts on the samples. The surface with smaller TiO2 particles deposited on carbon fiber is more appropriate for attachment of preosteoblasts. Furthermore, the highest proliferation of MC3T3-E1 was found on a sample with smaller TiO2 particles after incubation. Our data suggest that the increased roughness fosters cell attachment and proliferation on the surface of TiO2/carbon fibers.

An improved reduction method for phase stability testing in the single-phase region

A new reduction method for mixture phase stability testing is proposed, consisting in Newton iterations with a particular set of independent variables and residual functions. The dimension of the problem does not depend on the number of components but on the number of components with nonzero binary interaction parameters in the equation of state. Numerical experiments show an improved convergence behavior, mainly for the domain located outside the stability test limit locus in the pressure–temperature plane, recommending the proposed method for any applications in which the problematic domain is crossed a very large number of times during simulations.

Performance Evaluation of a Solar PV/T Water Heater Integrated with Inorganic Salt Based Energy Storage Medium

Thermal and Electrical performance of solar PV/T hybrid water heating system using salt mixture phase change materials in storage tank is analyzed in this study. Compare to all conventional type heaters, the solar PV/T hybrid module collector has ability to produces both electrical energy from PV module and utilizes incident solar energy to heat the water. The sheet and tube type absorber is used to heat up the tube which is attached at the back side of PV module and transfer the heat to flowing water and the electrical energy is tested by connecting the DC load on the PV terminals under glazed and unglazed modes respectively. To enhance the thermal performance, energy storage medium is used as phase change materials at good proportion in the tank. The thermo physical properties of PCM are analyzed by Differential Scanning Calorimetry. This experimental testing is conducted from 8.00 to 17.00 IST in various sunny days and results are compared for glazed and unglazed conditions. The results shows that the average water temperature easily reaches 38-45°C and the final temperature of water never dropped below 34°, the temperature of PCM is 45.6oC, which is 5oC higher than outlet. The amount of heat stored using PCM in tank is 16.86% greater than no-PCM in the tank for constant 0.01 kg/s mass flow rate. The daily average electrical efficiency is 6.4% under glazed mode and 8.8% under unglazed conditions.

Nonlinear Double-Log Mixing Rule for Viscosity Calculation of Bitumen/Solvent Mixtures Applicable for Reservoir Simulation of Solvent-Based Recovery Processes

Summary Various solvent-based recovery processes for bitumen and heavy-oil reservoirs have gained much interest in recent years. In these processes, viscosity reduction is attained not only because of thermal effects, but also by dilution of bitumen with a solvent. Accurate characterization of the oil/solvent-mixture viscosity is critical for accurate prediction of recovery and effectiveness of such processes. There are varieties of models designed to predict and correlate the mixture viscosities. Among them, the linear log mixing (Arrhenius) model is the most commonly used method in the oil industry. This model, originally proposed for light oils, often show poor performance (40 to 60% error) when applied to highly viscous fluids such as heavy oil and bitumen. The modified Arrhenius model, called the nonlinear log mixing model, gives slightly better predictions compared with the original Arrhenius model. However, the predictions still might not be acceptable because of large deviations from measured experimental data. Calculated mixture-phase viscosity has a significant effect on flow calculations in commercial reservoir simulators. Underestimation of mixture viscosities leads to overprediction of oil-production rates. Using such mixing models in reservoir simulation can lead to inaccuracy in mixture viscosities and hence large uncertainty in model results. In the present study, different correlations and mixing rules available in the literature are evaluated against the mixture-viscosity data for a variety of bitumen/solvent systems. A new form (nonlinear) of the double-log mixing rule is proposed, which shows a significant improvement over the existing models on predicting viscosities of bitumen/solvent mixtures, especially at high temperatures.

Numerical Analysis of Multi-Phase Flow around Supercavitating Body at Various Cavitator Angle of Attack and Ventilation Mass Flux

Cavitation flow is an important issue in many areas of mechanical engineering. In this study, the natural and ventilated cavitation analyses were performed using the developed code for the cavitation flow analysis. The governing equation is the Navier-Stokes equation based on a homogeneous mixture model. This model assumes that all fluids are in an equilibrium state of momentum. The momentum equations are solved using the homogeneous mixture phase, although the continuity equations are solved in the liquid, vapor, and gas phases, separately. Computational analysis was performed for the different injection conditions and inflow velocity conditions under the same conditions as the experiments. The comparison between the cavitation shape and the drag showed good agreement with the experiments. Based on this, this study predicted the change of cavitation shape according to the change of cavitator angle of attack.

ANALISA NPSH KERUSAKAN IMPELLER POMPA CETRIFUGAL CAIRAN CH3OH

Liquid behavior is always influenced by the environment in the form of temperature and pressure (thermodynamics). This temperature and pressure affect the nature of the change in liquid phase into a mixture of water and steam or vice versa. Pumps that function to drain liquid also have temperature and pressure. If the pressure drops and the temperature stays or rises at the pump, the liquid phase changes to a liquid and vapor mixture phase. This phase change in the pump (suction side) is called the phenomenon capitation. Capitation in the pump will cause erosion of the impellers parts, resulting in decreased performance. This study analyzes the erosion of the casing and impeller at the 040-G01S pump of PT. KMI from the point of phenomenon of capitation. The phenomenon of capitation in pump suction empirically can be known if the required NPSHa value is less or equal to the available NPSHr value or NPSHa ≦ NPSHr. The NPSHa value is affected by the suction pump installation configuration. To find out the cause of erosion on the casing and impeller, it is necessary to calculate the NPSH (Net Positive Section Head) required and those available (manufacturers). The results of this study NPSHa value = 4.75 m and NPSHr value = 5 m) or NPSHa ≦ NPSHr at tank level <45%. So it is necessary to modify the installation of the pump suction side piping.