About power of phase conversion current displace in junction metal - feroelektrik.

Household appliances utilize single-phase motors to perform everyday jobs whether it is to run a fan in an air conditioner or the compressor in a refrigerator. With the movement of the world going “green” and trying to make everything more efficient, it is a logical step to start with the items that we use every day. This can be done by replacing single-phase motors with three-phase motors in household appliances. Three-phase motors are 14% more efficient than single-phase motors when running at full load and typically cost less over a large range of sizes [1]. One major downside of incorporating three-phase motors in household appliance is that three-phase power is not readily available in homes. With the motor replacement, a single to three-phase converter is necessary to convert the single-phase wall power into the required three-phase input of the motor. One option is active conversion, which uses switches and introduces different stages that produce power loss [2]. An alternative solution is passive conversion that utilizes the resistances within the motor windings along with additional capacitors and inductors, which in theory are lossless. This study focuses on three different single to three-phase passive converters to run both wye and delta-connected three-phase induction motors, and a possible third winding configuration that utilizes one of the three converters. There will be an emphasis on proving the equivalency of two converters, one proposed by Stuart Marinus and Michel Malengret [11] and the other by Otto Smith [12]. Sensitivity analysis is performed to study the effects of variation of torque and converter component tolerances on the system.

2D semiconductors are one of the most promising materials for next-generation electronics. Realizing continuous 2D monolayer semiconductors with single-crystalline structure at the wafer scale is still a challenge. We developed an epitaxial phase conversion (EPC) process to meet these requirements. The EPC process is a two-step process, where the sulfurization process was carried out on pre-deposited Mo-containing films. Traditionally, two-step processes for 2D MoS2 and other chalcogenides have suffered low-quality film and non-discontinuity at monolayer thickness. The reason was regarded as the low lattice quality of precursor film. The EPC process solves these problems by carefully preparing the precursor film and carefully controlling the sulfurization process. The precursor film in the EPC process is epitaxial MoO2 grown on 2″ diameter sapphire substrate by pulsed laser deposition. This epitaxial precursor contains significantly fewer defects compared to amorphous precursor films. Thus fewer defects are inherited by the EPC MoS2 film. Therefore, EPC MoS2 film quality is much better. The EPC prepared monolayer MoS2 devices to show field-effect mobility between 10 ~ 30 cm2·V-1s-1, which is the best among the two-step process. We also developed a CLAP method further to reduce the defects in the precursor oxide film; thus, in-plane texture in the thicker MoS2 film was eliminated, and a single-crystalline structure was obtained in the wafer-scale MoS2 films. The potentially feasible technique to further improve the 2D film quality is pointed out for our next research plan. Meanwhile, the epitaxial phase conversion process was proposed to be as a universal growth method. Last but not least, we demonstrate several potential applications of the wafer-scale single-crystalline MoS2 film we developed, such as logic circuits, flexible electronics, and seeding layer of van der Waal or remote epitaxial growth.

yes / In all industrial petrochemical plants and refineries, the furnace is the source of heat resulting from fuel combustion with air. The model-based furnace simulation is considered one of the efficient methods help to reduce the energy loss and maintain fixed refinery revenues, conserving energy, and finally reducing external fuel consumption and total fuel cost. In this paper, a model-based simulation is carried out for a natural air draught industrial scale furnace related to Liquified Petroleum Gas (LPG) production plant in Libya to thoroughly investigate the most responsible factors in lowering the furnace butane exit temperature, which is supposed to be two degrees Fahrenheit higher than inlet temperature. Therefore, to resolve this industrial problem, Aspen Hysys V10, coupling with EDR (exchanger design and rating) is used to carry out rigorous model-based simulation. This is specifically used to assess the impact of heat loss from inside the firebox to the surrounding medium and heat loss from the furnace stack and walls, besides the effect of excess air on the furnace efficiency. Furthermore, this research intends to verify whether the operating conditions, such as furnace tubes inlet flow rate, temperature and pumping pressure, are conforming to the upstream process design specifications or need to be adjusted. The results confirm that increasing furnace outlet temperature two degrees Fahrenheit from off specification 190 °F instead of 184 °F is successfully achieved by decreasing upstream stream flowrate 25% below the operating value and cutback excess air gradually until 20%. Also, the results clarify the necessity of increasing the flue gas temperature by 7% over design condition, to gain a significant reduction of heat loss of 31.6% and reach as low as 35.5 MBtu/hr. This improvement is achieved using optimum operating conditions of an excess air of 20%, and flue gas oxygen content of 3.3% delivered to stack. Accordingly, the furnace efficiency has been increased by 18% to hit 58.9%. Furthermore, the heat loss from the furnace walls can be also reduced by 68% from 5.41 MBtu/hr to 1.7 MBtu/hr by increasing the refractory wall thickness to 6 in., which entails an increase in the furnace efficiency by 3.66% to reach 58.96%. Decreasing the heat loss fraction through the refractory wall, pip doors, expansion windows and refractory hair cracks would also increase the efficiency by 21% to reach a high of 59.7%. Accordingly, a significant reduction in daily fuel consumption is observed, which costs 1.7 M$ per year. The outcomes of this research clearly show the potential of reducing the operation and maintenance costs significantly.

Priority organic and emerging contaminants are a growing concern for drinking water treatment due to their increasing presence in the environment. This study developed a predictive model for the sorption of anionic organic contaminants from drinking water on three anion exchange resins: a strong polystyrenic (IRA-910), weak polystyrenic (IRA-96), and a strong polacrylic (A860). The model quantifies the individual mechanisms of sorption using poly-parameter linear free energy relationships (pp-LFERs) and the feasibility of phase conversion (e.g., an ideal gas phase as the reference state) for ionic species was examined. To develop the model, a training set of isotherms was obtained using aliphatic and aromatic carboxylates, phenols, anilines, nitrobenzene, and ibuprofen. These compounds were chosen as model organic contaminants in the environment. The training set and 1-3 test compounds (3-methyl-2-nitrobenzoate, phenol, and 4-nitroaniline) were accurately predicted using the created model for each resin. An understanding of the effects of resin structure on sorption interactions was also developed that focused on ionic functional groups, resin matrix, and hydrophilicity (i.e. water content). It was shown that greater sorption efficiency was achieved when electrostatic (ion exchange) and nonelectrostatic (adsorption) interactions were present together to create a synergistic addition. However, sorption on ion exchangers was poor if the pH of the system approached levels lower than the sorbate pKa. Additionally, weak base exchanges lose exchange capacity as pH levels approach resin pKa (IRA-96 pKa = 6.0). Additional contributions to the sorption mechanisms were observed by studying various electron donating/withdrawing functional groups on the contaminants. It was concluded that π-π and H-bonding interactions contributed a greater amount to the nonelectrostatic mechanisms than cavity formation forces and nonspecific forces. A comparison between the three resins showed that IRA-96 (weak base polystyrenic) had a greater removal capacity than IRA-910 (strong base polystyrenic), followed far behind by A860 (strong base polyacrylate). This is due to differences between the resins, such as the hydrophilicity, the density of the ion exchange group, and the presence of aromatic rings within the matrix structure. Although the modeling method accurately predicted the phase change from aqueous to sorbent phases, it was shown that the SPARC calculated aqueous-gas ion transfer energies were poor estimations of the transfer energy to the ideal gas phase and further study is necessary to accurately determine this value. This modeling methodology is believed to be applicable to emerging contaminants such as pharmaceuticals in water systems and helps further new water treatment technologies while developing a mechanistic understanding of electrostatic and nonelectrostatic interactions in general. This can be applied to additional separation processes such as chemical purification and chromatographic separation. / Civil Engineering