Effects of flash annealing and external magnetic field on magnetic properties of relatively high Nd content (37% by weight) NdFeB alloy

Journal of Materials Science: Materials in Electronics - Post modifications such as alloying element addition and/or heat treatment are applied to improve the magnetic properties of NdFeB permanent...     

Generalized differential quadrature analysis of electro-magneto-hydrodynamic dissipative flows over a heated Riga plate in the presence of a space-dependent heat source: The case for strong suction effect

The importance of including an electromagnetic actuator as a moving boundary on the dissipative flows of weakly conducting fluids had led to many published facts. But, nothing is known on the generalized differential quadrature analysis of magnetohydrodynamics over a Riga plate with emphasis on the case of viscous dissipation and space-dependent heat source. After deriving the simplified boundary layer equation that models the transport phenomenon, appropriate variables were used to non-dimensionalize and parameterize the partial differential equations. Thereafter, the resulting set of ordinary differential equations was solved numerically by applying a powerful differential quadrature algorithm. Based on the outcome of the simulation, it can be concluded that the viscous frictional effect can be minimized at the Riga plate either by weakening the suction process or by heightening the magnetic parameter. Moreover, the Lorentz forces have a hastening effect on the fluid motion, in the case when those magnetic causes are directed in the same sense of the developed flow.     

Settling characteristics of coal preparation plant fine tailings using anionic polymers

The objective of solid-liquid separation in thickeners in coal preparation plants is to obtain both a clear supernatant liquid with a low turbidity for reuse and a dense slurry. It is important for the smooth operation of the plant to produce good-quality recirculation water. In this study, settling characteristics of coal tailings (d₈₀=70 μm) taken from the thickener feed of Derekoy Coal Preparation Plant (Manisa, Turkey) were investigated with the use of anionic polymers. In the tests we determined the effects of the process parameters including polymer type, polymer dosage, temperature, suspension pH, and pulp density on the flocculation of the fine tailings of the coal preparation operation. Minefloc anionic polymer showed a better flocculation performance in comparison with other polymers. An optimum settling rate of 300 mm/min was reached at a dosage of 30 g/t-solids, a pulp density of 5%, pH 7.9, and temperature 25 °C using Minefloc polymer.     

Breakage of drops and bubbles in a stirred tank: A review of experimental studies

The rate of breakage of drops and bubbles (fluid particles) in stirred systems is of great consequence on mass,heat, and momentum transport phenomena. Therefore, over the years, the topic has gained a considerable attention fromthe researchers to study and characterize this phenomenon. In present work, the experimental studies of breakage phenomenon in a stirred tank in the last four decadeswere reviewed. The reviewhighlighted the investigated experimental conditions and the major findings concerning the breakagemechanismand the effect of operating conditions. The discrepancy and contradictions of the outcomes of those studies were specified and discussed. Experimental observations and conclusions concerning the breakage characterization parameters,such as deformation, breakage probability, breakage time, and breakage location were presented and commented on. Possible future refinements and prospective were recommended. The review indicated that there are clear discrepancies and contradictions between previous studies regarding the effect of some operating parameters and the values of breakage time, breakage probability, number of daughter particles, and breakage location relative to the impeller. In addition, there are still many scientific gaps that need to be studied and characterized in future by overcoming specific experimental difficulties and uncertainties.     

Study on emulsification of crude oil in water using emulsan biosurfactant for pipeline transportation

In this work, an experimental investigation on removing crude oil from a stainless steel tube using a biosurfactant such as emulsan was studied. The emulsan used in this study was produced by Acinetobacter calcoaceticus PTCC1318. The produced emulsan was able to reduce the surface and interfacial tension of water to 24 mN/m and 3 mN/m, respectively. Also influence of water- oil ratio on emulsifying property was studied. The results showed at CMC concentration, emulsification index (E₂₄) of emulsions decreased with increasing water- oil ratio. At 25°C, 30 mg/L, with a water–oil ratio of 1:2, produced emulsan formed an excellent emulsification of crude oil about 98%. Cleaning parameters tested included washing time and flow rate. It also demonstrated that the emulsan is useful for the tube cleaning with removal percentages of 100% at the room temperature, depending on the washing conditions.     

Sensitivity analysis of potential fuel savings by implementation of fuel economy standards for motorcycle

Due to the decrease in the total petroleum reserves worldwide, and the growing increase in the price of petroleum, fuel consumption has become the dominant factor in the selection of the proper vehicle. However, in some countries such as Malaysia, people tend to use fuel-efficient vehicles such as motorcycles. Statistics shows that in Malaysia, the number of motorcycles is almost half of the total registered vehicles. Therefore, motorcycles as widely used vehicles have an impact on overall energy consumptions in the country. Minimum fuel economy standard can be one of the effective policies to reduce the fuel consumption in transport sector. While the main problem to set the minimum fuel economy standard is to identify the annual fuel economy improvement of the vehicle, this study aims to find a method to calculate the annual fuel economy improvement and to calculate the potential reduction in fuel consumption by implementing a fuel economy standard for motorcycles in Malaysia. The calculation is based on four scenarios of sensitivity analysis which are 5, 10, 15, and 20 % from the baseline fuel economy. While this study only covers the fuel economy standard of motorcycles, the method can be applied to the other types of motor vehicles without major modifications.     

Determination of economic upper limit of drying processes in coal-fired power plants

In this study, the economic assessment of coal drying prior to ga rinding mill process in coal-fired thermal power plants was carried out. In the literature, despite the fact that there are studies regarding drying systems, the advantages and disadvantages of these systems in comparison to each other and the benefits that drying will provide, and the economic factors that are the most important determinants in the practice of the drying system, were not adequately analyzed. In this study, on the other hand, a model was developed to determine the necessary critical cost point in order to identify the appropriate drying system. Through the use of this model, the benefits to be gained from the planned drying system and the financial upper limit required for this investment can be specified. As a model application, eight of the thermal power plants in Turkey were examined. The economic upper limit of a drying system to enable coal to be dried at a rate of 10% was determined through a model study carried out for Catalagzi Power Plant.