Modeling and simulation of air-gapped current transformer based on Preisach Theory

Current Transformer (CT) modeling, by which CT’s characteristics can be studied has a significant importance in CT selection and design. In spite of numerous studies about closed-core CT model, only a few works have been conducted on air-gapped ones with the following problems: models of which required data is easily-accessible, have poor simulations of magnetization process; on the contrary, models which have satisfactory simulations, are hard to be established because of the hard-to-get required data. Therefore, based on Preisach Theory, a novel air-gapped CT model is deduced from the closed core CT model. The proposed model is accurate and can be established easily. The saturation and remanence properties of closed-core CT and air-gapped CT are simulated and compared.     

A Fuzzy Expert System for Evaluation of Demand-Side Management Alternatives

It is believed that the onset of true competition in the electric power industry may result in the demise of demand-side management (DSM) as it is known today, which is primarily a means of optimizing a utility's load curve. If DSM is to survive, utilities will need to evaluate the large number of possible options more efficiently and effectively than ever before. To reach this goal, the subjective portion of the evaluation process has been formulated into a fuzzy expert system, yielding faster, more efficient, and consistent results. This paper outlines the development of FEDSM, a Fuzzy Expert system designed to evaluate D emand-Side Management alternatives. FEDSM is a user-friendly, visual basic, and spreadsheet-based evaluation tool which allows the user to develop a flexible expert system. FEDSM is tested and evaluated on actual DSM data collected by a public utility in Nebraska, generating promising results.     

Novel inexpensive transition metal phosphide catalysts for upgrading of pyrolysis oil via hydrodeoxygenation

Supported molybdenum/molybdenum‐phosphides as inexpensive catalysts for bio‐oil hydrodeoxygenation (HDO) were in‐house prepared using different support materials, i.e., Al₂O₃, activated carbon (AC), MgAl₂O₄, and Mg₆Al₂(CO₃)(OH)₁₆. The HDO activity of these catalysts were investigated using a 100 mL bench‐scale reactor operating at 300°C with an initial hydrogen pressure of 50 bar for 3 h with a pyrolysis oil (PO). The catalytic efficiencies for bio‐oil HDO for the catalysts were compared with the expensive but commercially available Ru/C catalyst. Addition of small amount of P to the Mo catalysts supported on either AC and Al₂O₃ led to increased degree of deoxygenation (DOD) and oil yield compared with those without P. MoP supported on AC (MoP/AC) demonstrated bio‐oil HDO activity comparable to the Ru/C catalyst. Furthermore, three AC‐supported metal phosphides for PO HDO were compared under the same conditions, and they were found to follow the order of NiP/AC > CoP/AC > MoP/AC. © 2016 American Institute of Chemical Engineers AIChE J, 62: 3664–3672, 2016     

Improving machinability of Inconel 718 with a new hybrid machining technique

In this paper, by joining three non-traditional machining methods — plasma-enhanced machining, cryogenic machining, and ultrasonic vibration assisted machining — a new hybrid machining technique for machining of Inconel 718 is presented. Cryogenic machining reduces the temperature in the cutting zone, and therefore decrease tool wear and increases tool life, while plasma-enhanced machining helps to increase the temperature in the workpiece to make it softer. Also, applying ultrasonic vibrations to the tool helps to improve cutting quality and to prolong tool life by lowering, mainly, the cutting force and improving the dynamic cutting stability. This study experimentally investigates the effect of cutting parameters on cutting performance in the machining of Inconel 718 and compares the results of hybrid machining and conventional machining (CM). It is found that the hybrid method results in better surface finish and improves tool life in hard cutting at low cutting speeds as compared to the CM method.     

CALCULATING PSEUDO-STEADY-STATE HORIZONTAL OIL WELL PRODUCTIVITY IN RECTANGULAR DRAINAGE AREAS USING A SIMPLE METHOD

To determine the economical feasibility of drilling a horizontal well, engineers need reliable methods to estimate its productivity. In this work, a simple-to-use method is developed to rapidly estimate a pseudo-steady-state horizontal well's productivity. Estimations are found to be in excellent agreement with the reliable data in the literature, with average absolute deviation being less than 1%. The tool developed in this study can be of immense practical value for petroleum engineers to make a quick check on a pseudo-steady-state horizontal well's productivity at various conditions without opting for any field trials. The predictive tool is simple and straightforward, and it can be readily implemented in a standard spreadsheet program. The prime application of the method is as a quick-and-easy evaluation tool in conceptual development and scoping studies where horizontal wells are being considered. The method may also serve as a benchmark in numerical reservoir simulation studies.     

High speed and silicon-saving adaptive tuning system for high frequency Gm-C filters

In this paper, a novel adaptive tuning system used in Gm-C continuous time (CT) filters has been presented. The novelty of this method is the generation of quasi-gradient functions for the adaptive algorithm. By this method we have implemented the fully adaptive tuning algorithm on chip, and received more than 95% precision for the all characteristics of Gm-C filter. All the circuit level simulations and prototype fabrication have been done using 0.6 μ CMOS technology of AMS.     

Treatment of landfill waste,leachate and landfill gas: A review

This review aims at the treatment of the entire landfill, including the waste mass and the harmful emissions: leachate and landfill gas. Different landfill treatments (aerobic, anaerobic and semi-aerobic bioreactor landfills, dry-tomb landfills), leachate treatments (anaerobic and aerobic treatments, anammox, adsorption, chemical oxidation, coagulation/flocculation and membrane processes) and landfill gas treatments (flaring, adsorption, absorption, permeation and cryogenic treatments) are reviewed. Available information and the gaps present in current knowledge is summarized. The most significant areas to expand are landfill waste treatments, which in recent years has begun to grow but there is an opportunity for much more. Another area to explore is the treatment of landfill gas, a very large field to which not much effort has been put forth. This review is to compare different treatment methods and give direction to future research.     

Efficient preconcentration and determination of traces of aluminum ion using silica-bonded glycerol sorbent

A solid-phase extraction system was proposed for the determination of aluminum after preconcentration with glycerol-bonded silica gel. The method is rapid and efficient for the enrichment of aluminum ions at trace levels. Optimal sorption conditions were found for sorption and desorption of aluminum ions. The effects of diverse ions on the sorption and recovery of aluminum have been studied and it was shown that the selectivity of the sorption process was very good. A very satisfactory preconcentration factor of 500 was achieved by this method. The lowest concentration of aluminum ions for quantitative recovery was 2ngml(-1). The capacity of sorbent was 400microg per gram of sorbent. The method showed good reproducibility (R.S.D.=2.2% for n=7) and was applied to the determination of aluminum in mineral water, hair and green tea samples.     

Design of an adaptive-robust controller for a powder coating robot and its comparison with inverse dynamic approach

In this research, the design and function of “DAP”, a 3-DOF ‘RRP’ (rotational/prismatic) dual-acting pick-and-place-painting robot, are first briefly presented and, along with its kinematic and dynamic analysis, is studied to eliminate the man presence in industrially polluted environment such as coating processes. The main function of this robot is coating epoxy powder on “Hawle” gate valves at temperatures up to 200°C. Then, the movement and control simulation trend for maneuvering in optimization path are described by non-linear inverse dynamic and adaptive-robust controllers as modern control methods regarding to angle and torque feedback systems in industrial robots. Comparison of these control approaches is considered in relation to uncertainties. The results obtained from this research could greatly satisfy the need for overcoming uncertainties in such combined industrial processes.     

Hybrid connectionist model determines CO_2–oil swelling factor

In-depth understanding of interactions between crude oil and CO_2 provides insight into the CO_2-based enhanced oil recovery(EOR) process design and simulation. When CO_2 contacts crude oil, the dissolution process takes place. This phenomenon results in the oil swelling, which depends on the temperature, pressure, and composition of the oil. The residual oil saturation in a CO_2-based EOR process is inversely proportional to the oil swelling factor. Hence, it is important to estimate this influential parameter with high precision. The current study suggests the predictive model based on the least-squares support vector machine(LS-SVM) to calculate the CO_2–oil swelling factor. A genetic algorithm is used to optimize hyperparameters(у and б~2) of the LS-SVM model. This model showed a high coefficient of determination(R~2= 0.9953) and a low value for the mean-squared error(MSE = 0.0003) based on the available experimental data while estimating the CO_2–oil swelling factor. It was found that LS-SVM is a straightforward and accurate method to determine the CO_2–oil swelling factor with negligible uncertainty. This method can be incorporated in commercial reservoir simulators to include the effect of the CO_2–oil swelling factor when adequate experimental data are not available.