Plasma Discharge Process in a Pulsed Diaphragm Discharge System

As one of the most important steps in wastewater treatment, limited study on plasma discharge process is a key challenge in the development of plasma applications. In this study, we focus on the plasma discharge process of a pulsed diaphragm discharge system. According to the analysis, the pulsed diaphragm discharge proceeds in seven stages： （1） Joule heating and heat exchange stage; （2） nucleated site formation; （3） plasma generation （initiation of the breakdown stage）; （4） avalanche growth and plasma expansion; （5） plasma contraction; （6） termination of the plasma discharge; and （7） heat exchange stage. From this analysis, a critical voltage criterion for breakdown is obtained. We anticipate this finding will provide guidance for a better application of plasma discharges, especially diaphragm plasma discharges.

Fault Analysis and Innovation in Slag Discharge System of 440-t/h CFB Boiler

CFB boilers have been widely used in China in recent years with their perfect performances in coal adaptability, load variation capability and lower pollutant emission. The No.3 135-MW CFB unit in Lianzhou Power Plant is the f irst 440-t/h series CFB unit in Guangdong Province. It f inished 72-hour trial operation in Feb. 2004 and was transferred to trial operation. During the trial operation and the next commercial operation, there were some problems happened in the boiler slag discharging system, seriously affecting the safe and reliable operation and the loading capability. After innovation, these problems have been completely solved. Hopefully the solutions may be used for reference to the units with similar problems.

Degradation of Organic Compounds by Active Species Sprayed in a Dielectric Barrier Corona Discharge System

Investigation was made into the degradation of organic compounds by a dielectric barrier corona discharge （DBCD） system. The DBCD, consisting of a quartz tube, a concentric high voltage electrode and a net wrapped to the external wall （used as ground electrode）, was introduced to generate active species which were sprayed into the organic solution through an aerator fixed on the bottom of the tube. The effect of four factors-the discharge voltage, gas flow rate, solution conductivity, and pH of wastewater, on the degradation efficiency of phenol was assessed. The obtained results demonstrated that this process was an effective method for phenol degradation. The degradation rate was enhanced with the increase in power supplied. The degradation efficiency in alkaline conditions was higher than those in acid and neutral conditions. The optimal gas flow rate for phenol degradation in the system was 1.6 L/min, while the solution conductivity had little effect on the degradation.

Decoloration of Azo Dye Sunset Yellow by a Coaxial Insulated-Rod-to-Cylinder Underwater Streamer Discharge System

A coaxial insulated-rod-to-cylinder underwater streamer discharge system capable of injecting plasma into a large volume of water was developed and employed to decolorize azo dye sunset yellow. The rod type anode was covered by an insulator tube with a wall thickness of 0.4 mm. A series of slits with a width of 20 μm to 80 μm and a length of about 4 mm were cut onto the wall of the insulator tube. Depending on the solution conductivity, a cylindrical discharge region with a length of 60 mm and a wall thickness of 5 mm to 11 mm forms in the reactor. The influence of the solution conductivity, pH and pulse frequency on the decoloration of sunset yellow was investigated. The results show that the solution conductivity has little effect, while the solution pH and the pulse frequency have significant influence on the decoloration rate of sunset yellow. The decoloration rate of sunset yellow is increased with the increase in pulse frequency. A lower pH in solution promotes the decoloration of sunset yellow while a higher pH inhibits it.

Experimental Results on Excess Heat Power, Impurity Nuclides and X-Ray Production in Experiments with a High-Voltage Electric Discharge System

It reviewed results on low-energy nuclear reaction （LENR） processes in a high-voltage （1,000-4,000 V） electric discharge system. The experimental results are divided into three sets： excess heat measurements; yield of impurity nuclides （nuclear ash）; X-ray measurements. Up to 8 W of excess power was observed, with a power gain of up to 170% was seen in glow discharge experiments. Up to 300 W of excess power, with a power gain up to 340% was observed in experiments using a high-voltage electrolysis cell. The impurity nuclide yield showing a shift of up to a few per cent from natural isotopic abundances was detected by spark mass spectrometry, by secondary ionic mass spectrometry, and by secondary neutral mass spectrometry. X-ray emission in the range of 0.6-6.0 keV, has been observed. Based on these experimental results we propose a phenomenological model for LENR based on the interaction of an electric discharge with condensed matter （of the cathode）.

A Novel TiO_2 Combined Pulsed Diaphragm Discharge System for Phenol Degradation

A synergistic photocatalysis combined pulsed diaphragm discharge（PDD）system with TiO_2 nanofilm deposited on the surface of quartz diaphragm is developed for the first time for phenol degradation in an aqueous solution.It is observed that the decomposition efficiency of phenol in the TiO_2 combined PDD system is higher than that of the single PDD system under the same conditions,indicating a successful collaboration between the photocatalysis and the plasma decomposition in the present system.Analysis of the solution＇s pH value confirms this collaboration and further reveals that the photocatalytic enhancement effect of phenol degradation is strong at a relatively low supplied voltage.The present TiO_2 combined PDD system exhibits improved efficiencies of pollutant degradation and energy utilization,suggesting a good candidate for wastewater treatment.

Excess Heat Power Registration in Experiments with High Voltage Electric Discharge Systems

The author review results on LENR （low-energy nuclear reaction） processes in the cathodes of a high current glow discharge and a HVEC （high-voltage electrolysis cell）. The cathodes used in the experiments were made of Ni foil, Pd foil, Pd coated Re and solid-state nanostructured Pd. Up to 300 W of excess heat power, with a power gain up to 340%, was observed in experiments using a high-voltage electrolysis cell. Based on these experimental results, we propose a phenomenological model for LENR.

Development and Application of a Shaft-type Tubular Pumping System with a Siphon Discharge Passage

Based on the characteristics of large flow rate , low head , short annual operation time , and high reliability of the city flood-control pumping stations , a new-type shaft tubular pumping system featuring a shaft suction box and a siphon-type discharge passage with a vacuum breaker as the cutoff device was developed , which possesses such advantages as simple structure , reliable cutoff , and high energy performance.Taking some pumping stations as the case studies , in the light of the specified operation conditions , the hydraulic optimal design of the shaft-type tubular pumping system was determined and the optimized shape of the system was recommended.The performance prediction based on the computational fluid dynamics methodology was determined and the model test verification was conducted.The results show that the predicted data agree with the experimental head and efficiency so that both methods can be used to determine the performance of a real pumping station.Finally , the in-situ measurements of a pumping station during the commissioning period further verified that the shaft-type tubular pumping station with a siphon discharge passage is of higher efficiency , more reliable and stable.

Post-Anaesthetic Discharge Scoring System to assess patient recovery and discharge after colonoscopy

AIM: To investigate whether discharge scoring criteria are as safe as clinical criteria for discharge decision and allow for earlier discharge.METHODS: About 220 consecutive outpatients undergoing colonoscopy under sedation with Meperidine plus Midazolam were enrolled and assigned to 2 groups: in Control-group(110 subjects) discharge decision was based on the clinical assessment; in PADSS-group(110subjects) discharge decision was based on the modified Post-Anaesthetic Discharge Scoring System(PADSS).Measurements of the PADDS score were taken every20 min after colonoscopy, and patients were discharged after two consecutive PADSS scores ≥ 9. The investigator called each patient 24-48 h after discharge to administer a standardized questionnaire, to detect any delayed complications. Patients in which cecal intubation was not performed and those who were not found at follow-up phone call were excluded from the study.RESULTS: Thirteen patients(7 in Control-group and6 in PADSS-group) were excluded from the study. Recovery from sedation was faster in PADSS-group than in Control-group(58.75 ± 18.67 min vs 95.14 ± 10.85min, respectively; P < 0.001). Recovery time resulted shorter than 60 min in 39 patients of PADSS-group(37.5%), and in no patient of Control-group(P < 0.001).At follow-up phone call, no patient declared any hospital re-admission because of problems related to colonoscopy and/or sedation. Mild delayed post-discharge symptoms occurred in 57 patients in Control-group(55.3%)and in 32 in PADSS-group(30.7%). The most common symptoms were drowsiness, weakness, abdominal distension, and headache. Only 3 subjects needed to take some drugs because of post-discharge symptoms.CONCLUSION: The Post-Anaesthetic Discharge Scoring System is as safe as the clinical assessment and allows for an earlier patient discharge after colonoscopy performed under sedation.

Probabilistic analysis for the response of nonlinear base isolation system under the ground excitation induced by high dam flood discharge

According to theoretical analysis, a general characteristic of the ground vibration induced by high dam flood discharge is that the dominant frequency ranges over several narrow frequency bands, which is verified by observations from the Xiangjiaba Hydropower Station. Nonlinear base isolation is used to reduce the structure vibration under ground excitation and the advantage of the isolation application is that the low-frequency resonance problem does not need to be considered due to its excitation characteristics, which significantly facilitate the isolation design. In order to obtain the response probabilistic distribution of a nonlinear system, the state space split technique is modified. As only a few degrees of freedom are subjected to the random noise, the probabilistic distribution of the response without involving stochastic excitation is represented by the δ function. Then, the sampling property of the δ function is employed to reduce the dimension of the Fokker-Planck-Kolmogorov （FPK） equation and the low-dimensional FPK equation is solvable with existing methods. Numerical results indicate that the proposed approach is effective and accurate. Moreover, the response probabilistic distributions are more reasonable and scientific than the peak responses calculated by conventional time and frequency domain methods.

Research on quinoline degradation in drinking water by a large volume strong ionization dielectric barrier discharge reaction system

Quinoline is widely used in the production of drugs as a highly effective insecticide,and its derivatives can also be used to produce dyes.It has a teratogenic carcinogen to wildlife and humans once entering into the aquatic environment.In this study,the degradation mechanism of quinoline in drinking water by a strong ionization dielectric barrier discharge(DBD)lowtemperature plasma with large volume was explored.High concentration of hydroxyl radical(·OH)(0.74 mmol l^(-1))and ozone(O3)(58.2 mg l^(-1))produced by strongly ionized discharge DBD system were quantitatively analyzed based on the results of electron spin resonance and O3 measurements.The influencing reaction conditions of input voltages,initial pH value,·OH inhibitors,initial concentration and inorganic ions on the removal efficiency of quinoline were systematically studied.The obtained results showed that the removal efficiency and TOC removal of quinoline achieved 94.8%and 32.2%,degradation kinetic constant was 0.050 min^(-1) at 3.8 k V and in a neutral pH(7.2).The proposed pathways of quinoline were suggested based on identified intermediates as hydroxy pyridine,fumaric acid,oxalic acid,and other small molecular acids by high-performance liquid chromatography/tandem mass spectrometry analysis.Moreover,the toxicity analysis on the intermediates demonstrated that its acute toxicity,bioaccumulation factor and mutagenicity were reduced.The overall findings provided theoretical and experimental basis for the application of a high capacity strong ionization DBD water treatment system in the removal of quinoline from drinking water.

Cross influence of discharge and circulation on head loss of conduit of pump system with low head

The relationship between the head loss and the discharge and circulation of the conduit of a pump system with low head is an important problem with an obvious influence on the improvement of its hydraulic performance. The velocity circulation from the pump guide vane makes the relationship more complicated, which has to be understood comprehensively. The results indicate that, under the condition of zero circulation, the head loss of the inlet and outlet conduits is in proportion to the square of discharge. Under the condition that the Reynolds number is satisfied with the resistant square area, the conduit loss is in proportion to the square of discharge for the similar working points with different speeds in a certain rotational speed range, indicating that the pump system efficiency is constant. The outlet conduit loss of design discharge for a pump system with low head depends on the velocity circulation from the guide vane exit, and the relationship between the loss and the circulation is an open curve with an upward direction, meaning that there is an optimal circulation for the loss. Under the condition of various working points for a pump system with low head, the head loss of the outlet conduit is under the cross influence of both the discharge and the circulation. As a result, the relationship between the head loss and the discharge is almost linear, and the mechanism needs to be further studied.

A Study on the Mobile Partial Discharge Locating System

This paper studies on the Partial Discharge (PD) Locating System based on a mobile array of ultra-high frequency (UHF) antennas and a vehicle-mounted PD locating system is established. The system consists of omni-directional antenna array for receiving UHF PD signals, a pre-processing circuit for signal amplification and filtering and the high- speed acquisition and control unit of PD pulse signals. The developed locating system is able to simultaneously record the PD pulse signals received by the antenna array. By assessing the time difference of arrival (TDOA), the two-dimensional hyperbolic locating model quickly locates the PD source. Based on the software developed by LabVIEW, it is also possible to display, store and further analyze the acquired signals. Through the simulation of PD signals and the locating experiments with the system, it is proved that the PD locating system possesses the features of rapidity and precision in determining the bearing of PD source.

Numerical simulation of karst groundwater system for discharge prediction and protection design of spring in Fangshan District, Beijing

As the rapid growth of population and social economy, the situation of water resources shortage in Beijing city becomes more and more serious. Karst groundwater in Beijing has great potential for development. The reasonable exploitation of karst groundwater can enhance the water-supply stability of Beijing city. Firstly, the distribution of springs has been investigated in Fangshan, Beijing, and the characteristics of these springs have also been analyzed. Secondly, the hydrogeological conceptual model has been built, based on this, the groundwater flow numerical simulation model was established, and the parameter identification and validation of the model were performed under groundwater level and spring discharge. The results shows that the simulated values of groundwater level and spring discharge are very close to measured values, and the model can be used for groundwater resources evaluation and spring discharge prediction. Finally, a reasonable exploitation design has been developed with three exploitation scenarios considering the spring discharge protection; meanwhile, the quantity of groundwater resources was evaluated in the karst aquifer. The simulation results indicate that different exploitation yields have a significant impact on spring discharge; and the effective measures should be taken to protect the spring discharge.

Design of DC Partial Discharge Detecting System for Electrical Equipment

A balancing method was used to build a DC partial discharge （PD） testing circuit for electrical equipment,and a narrow-band detection system was designed using detection resistance and a filter. After signal accessed a high-speed digital acquisition （DAQ） card,the system was triggered to extract a single partial discharge （PD） signal. To eliminate the interference pulses caused by power supply ripple,etc.,the time domain and frequency domain features of pulses were extracted. Based on the features,cluster analysis was used to exclude interference pulses. Two-dimensional and three-dimensional histograms were obtained by use of the Δt method. Then,22 discharge statistical operators were calculated for the two-dimensional charts. Lastly,the defective capacitors were tested to verify the system＇s ability. The results show that the system is capable of PD detection in electrical equipment.

An On-line Monitoring System for Partial Dischargefrom High Voltage Transformer

An on-line monitoring system for partial discharge from high voltage transformer is presented with structure of hardware and principle of software discussed and a new effective method combining DFT with DWT is proposed to get rid of both sinusoidal continuous noise and other external discharges.

Improving plasma sterilization by constructing a plasma photocatalytic system with a needle array corona discharge and Au plasmonic nanocatalyst

Efficient sterilization by a plasma photocatalytic system(PPS)requires strong synergy between plasma and photocatalyst to inactivate microorganisms while suppressing the formation of secondary pollutants.Here,we report that a PPS constructed from a needle array corona discharge and Au/TiO2plasmonic nanocatalyst could remarkably improve the sterilization of Escherichia coli(E.coli)and alleviate formation of the discharge pollutant O3.At 6 kV,the combination of corona discharge and Au/TiO2achieves sterilization efficiency of 100%within an exposure time of 5 min.At 5 kV and an exposure time of 8 min,the presence of Au/TiO2improves sterilization efficiency of the corona discharge from 73%to 91%and reduces the O3concentration from 0.38 to 0.04 ppm,whereas the presence of TiO2reduces the sterilization efficiency and O3concentration to 66%and 0.17 ppm,respectively.The Au/TiO2in the PPS enables a uniform corona discharge,enhances the interaction between plasma,E.coli and nanocatalysts,and suppresses the formation of O3.Further,the Au/TiO2can be excited by ultraviolet-visible light emitted from the plasma to generate electron-hole pairs,and thus contributes to the formation of reactive radicals and the oxidative inactivation of E.coli.The PPS constructed from a needle array corona discharge and Au-based plasmonic nanocatalyst provides a promising approach for developing high-efficiency sterilization techniques.

Integrated CAD/CAPP/CAM system for electric discharge machining

An integrated CAD/CAPP/CAM system modeling for Electric Discharge Machining (EDM) is constructed on the basis of an integrated engineering database. EDM feature objects are developed using the object oriented database provided by AutoCAD R14, and EDM feature modeling is realized in AutoCAD environments.

Analysis of the critical active species for methylene blue decoloration in a dielectric barrier discharge plasma system

In the paper, a hybrid gas–liquid dielectric barrier discharge(DBD) plasma system was set up to treat a methylene blue(MB) solution. The effects of the change of the carrier gas, the gas bubbling rate and different kinds of scavenger addition, including sodium carbonate(Na_2CO_3),para benzoquinone(p-BQ), triethylenediamine and sodium dihydrogen phosphate(NaH_2PO_4),on the MB decoloration were reviewed to clarify the critical active species for the dye decoloration in the DBD plasma system. The obtained results show that higher decoloration of the MB solution could be achieved when O2 was used as the carrier gas, which could be 100% after 20 min discharge treatment, and the result confirmed the crucial effect of O_3 in the MB decoloration. Based on the experiments of the scavenger addition, it could be concluded that O_2·^- and ~1O_2 were two other important reactive oxygen species(ROS) for the MB decoloration.The results of the higher chemical oxygen demand removal and faster disappearance of the characteristic peak of the MB from the UV–vis analysis under O_2 bubbling conditions also proved the critical effect of the ROS formed by O_2 on the MB decoloration.

The Paediatric Observation Priority Score: A System to Aid Detection of Serious Illness and Assist in Safe Discharge

The Paediatric Observation Priority Score (POPS) is a bespoke assessment tool for use in Paediatric Emergency Departments incorporating traditional physiological parameters alongside more subjective observational criteria. Initial performance characteristics of POPS were analysed in a convenience sample of 936 presentations to ED. Triage on the basis of gut instinct parameters identified an additional 261 patients deemed of lowest acuity compared to analysis by physiology scores. Resource consumption increased with increasing acuity on presentation. POPS shows promise in assisting in the assessment process of children presenting to Emergency Departments. Inclusion of subjective triage criteria helps contextualise the physiological parameter scoring by using the experience of staff conducting triage. Initial interpretation of presenting physiology gives a more informed assessment of initial acuity, and thus is better able to identify a child who can be safely managed in the community. The system also allows for rapid detection of those most unwell.