Characterization of a 3-Phase a.c. Free Burning Arc Plasma

A 3-phase a.c. arc plasma reactor with large volume plasma has been developed for the synthesis of new carbon nano-structures. One of the main characteristics of the plasma system is related to the absence of a fixed neutral point. This gives rise to a rich and complex phenomenology related to instabilities and arc motion since the arcs are ＂burning＂ freely in the gas flow between the three electrodes. This paper is dedicated to the analysis of the behavior of such a system under typical conditions using argon and nitrogen as plasma gases. A classification of are configuration, arc commutating, arc interaction, arc motion and arc instabilities are discussed based on ultra high-speed cine camera analysis. A simple model describing the time evolution of the system is also presented and compared with the experimental measurements. The results show that an adequate control could allow the improvement of the overall system.

A new design of stator magnetic system for 3-phase & 12-pole HB stepper

A new design of stato magnetic System is Proposed for 3-phase & 12-pole HB stepper, and it features bet-ter distribution of magntic lield to incare Pullou tope and bopmve Operaonal stability of moor and minimummutual inductance between phase windimp to make design of control circuit easier, and application proved it is as good as expected.

3-Phase Modeling for the Origin of Chinese Lithium-Rich Brines

There are significantly different origins and mineralizations among various lithium-rich brines of the world.As for Clayton Valley,Nevada,the data and interpretations recently presented suggest that the model

Improvement of β-phase crystal formation in a BaTiO3-modified PVDF membrane

In this paper,low temperature plasma is used to modify the surface of barium titanate（BaTiO3）nanoparticles in order to enhance the interfacial compatibility between ferroelectric poly（vinylidene fluoride）（PVDF） and BaTiO3 nanoparticles.The results demonstrate that oxygenic groups are successfully attached to the BaTiO3 surface,and the quantity of the functional groups increases with the treatment voltage.Furthermore,the effect of modified BaTiO3 nanoparticles on the morphology and crystal structure of the PVDF/BaTiO3 membrane is investigated.The results reveal that the dispersion of BaTiO3 nanoparticles in the PVDF matrix was greatly improved due to the modification of the BaTiO3 nanoparticles by air plasma.It is worth noting that the formation of a β-phase in a PVDF/modified BaTiO3 membrane is observably promoted,which results from the strong interaction between PVDF chains and oxygenic groups fixed on the BaTiO3 surface and the better dispersion of BaTiO3 nanoparticles in the PVDF matrix.Besides,the PVDF/modified BaTiO3 membrane at the treatment voltage of 24 k V exhibits a lower water contact angle（≈68.4°） compared with the unmodified one（≈86.7°）.Meanwhile,the dielectric constant of PVDF/BaTiO3 nanocomposites increases with the increase of working voltage.

Fault diagnosis algorithm for 3-phase passive rectifiers based on frequency-domain analysis for acceleration grid power supply in CFETR NBI system

The acceleration grid power supply(AGPS) is a crucial part of the Negative-ion Neutral Beam Injection system in the China Fusion Engineering Test Reactor,which includes a 3-phase passive(diode) rectifier.To diagnose and localize faults in the rectifier,this paper proposes a frequencydomain analysis-based fault diagnosis algorithm for the rectifier in AGPS.First,time-domain expressions and spectral characteristics of the output voltage of the TPTL-NPC inverter-based power supply are analyzed.Then,frequency-domain analysis-based fault diagnosis and frequency-domain analysis-based sub-fault diagnosis algorithms are proposed to diagnose open circuit(OC) faults of diode(s),which benefit from the analysis of harmonics magnitude and phase-angle of the output voltage.Only a fundamental period is needed to diagnose and localize exact faults,and a strong Variable-duration Fault Detection Method is proposed to identify acceptable ripple from OC faults.Detailed simulations and experimental results demonstrate the effectiveness,quickness,and robustness of the proposed algorithms,and the diagnosis algorithms proposed in this article provide a significant method for the fault diagnosis of other rectifiers and converters.

A Device for Measuring 3-Phase Alternating Current at a Distance

We have made a preliminary study on a possibility to build a device, which could measure three-phase alternating current at a distance. This report gives a brief look at the theoretical background related with such a device and derives several mathematical results associated with the theory and the structure of the device. Our results suggest that such a device can be built, assuming the distances between the three current-carrying wires and the two sensors of the device are known accurately enough. There are ways to measure these distances, but this article does not concentrate on them.

Hyperbranched phthalocyanine enabling black-phase formamidinium perovskite solar cells processing and operating in humidity open air

The extreme instability of pureα-phase FAPbI_(3) under high humidity conditions restricts the highthroughput fabrication in unmodified air environments,resulting in poor performance ofα-phase FAPbI_(3) perovskite devices obtained by scalable fabrication methods.Here we synthesized hyperbranched copper phthalocyanine(HCuPc)as a supramolecular additive with twisted phthalocyanine units to realize the molecular-level encapsulation at the grain boundaries through supramolecular interaction,which greatly broadened the processing window of FAPbI_(3) under high humidity.At the same time,unlike traditional encapsulation layer that carrier can only be collected by tunneling effect,the twisted phthalocyanine ring of HCu Pc in perovskite films is more conducive to hole extraction.Finally,a record efficiency was achieved in pure FAPbI_(3) based inverted structured solar cell by blade-coating to the best of our knowledge,even under unmodified humid air conditions(relative humidity of 65%–85%).The best operational stability of 3D pure FAPbI_(3) devices can also be achieved at the same time and unencapsulated HCuPc-FAPbI_(3) device can even operate with negligible degradation for 100 h in the open air(RH 30%–40%).

ON THE ORDERING TRANSFORMATIONS IN Ti_3AL-Nb ALLOY

Study was made of the behaviour of ordering transformation in Ti_3AI-Nb alloy,including the ordering at high temperatures,the transformation of high temperature β-phase during cooling,and the decomposition of metastable β-phase during aging.The results show that the ordered primary α_2 and high temperature β in alloy form at 1060℃.The transformation of high temperature β-phase proceed by β→α_2+ω type during cooling,and the decomposition of metastable β and ω type proceeded by(β+ω)_(metustabte)→(α_2+β)_(stable)during aging at 700℃.

A new level set model for cell image segmentation

In this paper we first determine three phases of cell images： background, cytoplasm and nucleolus according to the general physical characteristics of cell images, and then develop a variational model, based on these characteristics, to segment nucleolus and cytoplasm from their relatively complicated backgrounds. In the meantime, the preprocessing obtained information of cell images using the OTSU algorithm is used to initialize the level set function in the model, which can speed up the segmentation and present satisfactory results in cell image processing.

Adaptive optimization of agile organization of command and control resource

Adaptive optimization is one of the means that agile organization of command and control resource （AOC2R） adapts for the dynamic battlefield environment. A math model of the adaptive optimization of AOC2R is put forward by analyzing the interrelating concept and research. The model takes the adaptive process as a multi-stage decision making problem. The 2-phases method is presented to calculate the model, which obtains the related parameters by running the colored Petri net （CPN） model of AOC2R and then searches for the result by ant colony optimization （ACO） algorithm integrated with genetic optimization techniques. The simulation results demonstrate that the proposed algorithm greatly improves the performance of AOC2R.

Simulation and reliability analysis of shunt active power filter based on instantaneous reactive power theory

This paper first discusses the operating principle of instantaneous reactive power theory. Then, the theory is introduced into shunt active power filter and its control scheme is studied. Finally, Matlab/Simulink power system toolbox is used to simulate the system. In the simulation model, as the most common harmonic source, 3-phase thyristor bridge rectifier circuit is constructed. The simulation results before and after the shunt active filter was switched to the system corresponding to different firing angles of the thyristors are presented and analyzed, which demonstrate the practicability and reliability of the proposed shunt active filter scheme.

Modeling and Simulation of Two-Staged Separation Process for an Onshore Early Production Facility

Early Production Facilities are makeshift process deployment that ensures that marginal oilfield operators make revenues from their new discoveries with little cash outlay and limited investment risks. Authors have in past simulated a gas process facility using Hysys without particularly developing mathematical models for the key equipment. There also has been modeling of phase separation dynamics and process simulation but still without models for equipment. We basically developed models for the critical process equipment for early production, sized the equipment with data from a marginal field in the Niger delta region of Nigeria and then ran a dynamic simulation with the sized equipment. The important elements of the deployment are two-phase process vessel, 3-phase process vessel;knock-out drum, produced water treatment unit. Mathematical models were developed and adapted with Mathlab for the equipment sizing whilst ASPEN PLUS was used for simulating the process. Process data retrieved from a marginal field in Nigeria was used as input to quantify the equipment models. Sized equipment was deployed in Hysys V8.8 for a steady and dynamic state. The system simulation was comprised of a two-phase process vessel followed by a 3-phase process vessel [1]. The unwanted gas was sent to knock out drum for removal of entrained liquid droplets before flaring (this was because the volume of gas processed is deemed uneconomical) and produced water to treatment unit for removing droplets of oil before disposal. Gas, oil and water were fed into the first stage separator (2-phase) at 132918.34 Ibmole/hr, 7622.95 Ibmole/hr and 1082.74 Ibmole/hr respectively. The operating pressures of the first and second vessels were at 850 psi and 150 psi respectively. The 2-phase vessel flashed off 96.7% of the gas and increased the liquid recovery by 3.3%. At the end of the second stage separation, oil yield increased by 270 Ibmole/hr, the gas increased by 110.15 Ibmole/hr whilst water reduced by 379 Ibmole/hr. This result confirmed that the vessels were sized to optimize recovery of hydrocarbons entrained in the various phases into the most required oil phase.

Elimination of Partial Overloading of Generators Under Unbalanced Operating Conditions of Power Systems

Unbalanced operating condition in a power system can cause partial overloading of the generators in the network,a condition where one or two of the three phases of the generator become overloaded even if the total 3-phase power output of the generator is within its specified limit.Partial overloading of generators beyond certain limits is undesirable and must be avoided.Distribution systems are often subjected to highly unbalanced operating conditions.Introduction of distributed generations(DGs),therefore,has rendered today’s distribution systems quite susceptible to this problem.Mitigation of this problem requires the issue to be addressed properly during analysis,operation and planning of such systems.Analysis,operation and planning of power networks under unbalanced operating condition require 3-phase load flow study.The existing methods of 3-phase load flow are not equipped to take into account any limit on the loadings of the individual phases of the generators.In the present work,a methodology based on NewtonRaphson(N-R)3-phase load flow with necessary modifications is proposed.The proposed methodology is able to determine the safe loading limits of the generators,and,can be adopted for operation and planning of power networks under unbalanced operating conditions to overcome the above difficulties.Test results on IEEE-37 bus feeder network are presented to demonstrate the effectiveness of the proposed method.