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INDUCTIVELY COUPLED PLASMA MASS-SPECTROMETRY FOR THE DETERMINATION OF ALUMINUM, CALCIUM, CHLORINE, IRON, MAGNESIUM, MANGANESE AND SODIUM IN FRESH-WATER

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ANALYTICAL LETTERS 1992年第5期25卷 919-936页

作者： VANHAECKE, F VANDECASTEELE, C DAMS, R [a] Laboratory of Analytical Chemistry Ghent University Institute for Nuclear Sciences Gent Belgium

In the frame of a certification campaign organised by BCR (Bureau Communautaire de Reference, Commission of the European Communities, Brussels), Al, Ca, Cl, Fe, Mg, Mn and Na were determined in two candidate reference materials, low mineral content fresh water CRM 398 and high mineral content fresh water CRM 399. The concentration of the elements ranged from 30 ng/g (for Mn) to 80-mu-g/g (for Ca). Metals present at relatively high concentrations were determined under operating conditions of non-optimal sensitivity, but with no loss in precision. The accuracy and precision of the results obtained by ICP-MS were checked by comparing with other analytical techniques and laboratories. The agreement was excellent. This study showed that ICP-MS not only yields excellent results for interference-free elements at trace levels, but is also competitive for less ideal elements e.g. Ca, Fe and Cl.

关键词： ICP-MASS SPECTROMETRY FRESH WATER operation parameters CERTIFICATION CAMPAIGN

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Thermal comfort analysis of radiant cooling panels with dedicated fresh-air system

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INDOOR AND BUILT ENVIRONMENT 2021年第10期30卷 1596-1608页

作者： Qin, S. Y. Cui, X. Yang, C. Jin, L. W. Xi An Jiao Tong Univ Inst Bldg Environm & Sustainable Technol Xian Peoples R China Nanyang Technol Univ Sch Mech & Aerosp Engn Singapore Singapore

Radiant system has been increasingly applied in buildings due to its good thermal comfort and energy-saving potential. In this research, a simplified predicted mean vote (PMV) model and sensible cooling load equation were proposed based on human thermal comfort. Simulations were carried out using Airpak to explore relationships among thermal comfort characteristics, design and operation parameters. Results show that radiant surface temperature, fresh-air supply temperature and the area ratio are correlated approximately linearly with the indoor air temperature, while the relative humidity has little effect on the indoor air temperature. The indoor air velocity in the simulated environment was no more than 0.15 m/s, satisfying the requirements of limit values in the occupied zone. The results indicate that the optimum radiant surface temperature (t(c)) is 19 degrees C to 23 degrees C when fresh-air supply temperature (t(s)) is 26 degrees C. The relative humidity (phi) should be maintained at 50% to 70%, and the area ratio of radiant panels to total surfaces (k(1)) should be kept within 0.15 to 0.38 when the radiant surface temperature is 20 degrees C and the fresh-air supply temperature is 26 degrees C. The simplified PMV model and the sensible load equation can provide reference for panel design based on characteristics of radiant cooling panels with a dedicated fresh-air system.

关键词： Radiant cooling panels Fresh-air system Thermal comfort PMV index operation parameters

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Influence of operational parameters and design of the ejection nozzle on characteristics of finely dispersed aluminum powder: Part I. Influence of operational parameters of the nozzle

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RUSSIAN JOURNAL OF NON-FERROUS METALS 2016年第2期57卷 131-134页

作者： Arkhipov, V. A. Evsevleev, M. Ya. Zharova, I. K. Zhukov, A. S. Zmanovskii, S. V. Kozlov, E. A. Konovalenko, A. I. Tomsk State Univ Res Inst Appl Math & Mech Pr Lenina 36 Tomsk 634050 Russia Innovat Ctr Branch OOO Sual PM Ul Yuzhnaya 2 Irkutsk 666034 Irkutsk Oblast Russia

The results of analyzing the influence of operational parameters of the ejection nozzle on the characteristics of highly dispersed aluminum powder in production conditions at OOO SUAL-PM are presented. Measurements of dispersed characteristics of the spray when spraying the aluminum melt by the ejection nozzle are performed when varying the consumption and temperature of spraying gas in ranges of 0.17-0.21 m(3)/s and 873-933 K, respectively, as well as the melt temperature in limits of 1153-1253 K. The results of determining the median diameter of the particles (d (m) ) and content of the highly dispersed fraction (z) (with a particle diameter no larger than 10 mu m) in the spray are presented. It is shown that, when modifying the operation parameter of the nozzle, the value of d (m) decreases by 3.7-12.4%, while the magnitude of z increases by 0.4-3.2%. It is established that an increase in temperature of spraying gas affects the powder properties most effectively.

关键词： ejection nozzle aluminum melt spraying gas scattering torch spray highly dispersed powder fraction median diameter of particles operation parameters gas flow rate gas temperature melt temperature

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Optimization of operation conditions for preventing sludge bulking and enhancing the stability of aerobic granular sludge in sequencing batch reactors

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WATER SCIENCE AND TECHNOLOGY 2014年第9期70卷 1519-1525页

作者： Zhou, Jun Wang, Hongyu Yang, Kai Ma, Fang Lv, Bin Wuhan Univ Sch Civil Engn Wuhan 430072 Peoples R China Harbin Inst Technol State Key Lab Urban Water Resource & Environm Harbin 150090 Peoples R China Wuhan Text Univ Sch Environm & Urban Construct Wuhan 430073 Peoples R China

Sludge bulking caused by loss of stability is a major problem in aerobic granular sludge systems. This study investigated the feasibility of preventing sludge bulking and enhancing the stability of aerobic granular sludge in a sequencing batch reactor by optimizing operation conditions. Five operation parameters have been studied with the aim to understand their impact on sludge bulking. Increasing dissolved oxygen (DO) by raising aeration rates contributed to granule stability due to the competition advantage of non-filamentous bacteria and permeation of oxygen at high DO concentration. The ratio of polysaccharides to proteins was observed to increase as the hydraulic shear force increased. When provided with high/low organic loading rate (OLR) alternately, large and fluffy granules disintegrated, while denser round-shape granules formed. An increase of biomass concentration followed a decrease at the beginning, and stability of granules was improved. This indicated that aerobic granular sludge had the resistance of OLR. Synthetic wastewater combined highly and slowly biodegradable substrates, creating a high gradient, which inhibited the growth of filamentous bacteria and prevented granular sludge bulking. A lower chemical oxygen demand/N favored the hydrophobicity of granular sludge, which promoted with granule stability because of the lower diffusion rate of ammonia. The influence of temperature indicated a relatively low temperature was more suitable.

关键词： aerobic granular sludge hydrophobicity operation parameters sequencing batch reactor sludge bulking stability

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Vacuum membrane distillation to remove ethyl acetate from aqueous solutions

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DESALINATION AND WATER TREATMENT 2014年第25-27期52卷 5158-5164页

作者： Li, Xin Li, Jilei Wu, Lili Beijing Inst Technol Sch Chem Engn & Environm Beijing 100081 Peoples R China

Water pollution of volatile organic compounds (VOCs) was a serious environment problem. Vacuum membrane distillation (VMD) was an environmental friendly membrane separation technology to treat VOCs wastewater. Aqueous binary mixtures of ethyl acetate were treated by VMD process. Comparisons were made between different membrane modules for investigating the influence of channel on the membrane separation performance. Three kinds of channel presented different useful area, shape, width, and depth. The arc flow channel was more easier to reduce resistance than square flow channel. operation parameters influencing flux and separation performance were examined: feed-flow rate, feed concentration, vacuum degree, and feed temperature. Vacuum degree and feed temperature had more significant influence on membrane flux and separation factor than other parameters. The effect of membrane type on separation properties was also investigated, the smaller pore membrane was better for increasing the separation factor. Three membrane modules with various channels were used for experiments. VMD is very suitable for low concentration of aqueous solution VOC separation and better experimental separation performance could be obtained.

关键词： Vacuum membrane distillation Membrane module operation parameters Ethyl acetate solution

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Effects of Operating parameters for Dynamic PWM Variable Spray System on Spray Distribution Uniformity

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IFAC-PapersOnLine 2016年第16期49卷 216-220页

作者： Jiang, Huanyu Zhang, Lijun Shi, Weinan College of Biosystems Engineering and Food Science Zhejiang University Hangzhou310058 China

A dynamic PWM (Pulse Width Modulation) variable spray experiment platform was built up to study the spray distribution characteristics of PWM spray progress. The homogeneity of single nozzle dynamic spraying was evaluated based on this platform under different experiment condition. Carmine solution concentration-absorbance technology was adopted to get the CV (Coefficient of Variation) value of percent area spray coverage. RSM (Response Surface Methodology) with three variables including frequency, duty cycle of PWM control signal and forward velocity of spray was employed to study the effects of these three factors on dynamic spray distribution uniformity. Compared with previous common study of static spraying, the research on this paper can evaluate the actual spray distribution uniformity of dynamic spraying more accurately. Moreover, the platform and the research method can provide references for the settings of PWM variable-rate spray operation parameters in practical plant protection work. © 2016

关键词： Spray nozzles Pulse width modulation Voltage control Coefficient of variation Dynamic variables Experiment platforms Operating parameters operation parameters Response surface methodology Solution concentration Spray distribution

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Methane steam reforming for synthetic diesel fuel production from steam-hydrogasifier product gases

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KOREAN JOURNAL OF CHEMICAL ENGINEERING 2008年第6期25卷 1279-1285页

作者： Jeon, Seok Ku Park, Chan Seung Kim, Sang Done Song, Byung Ho Norbeck, Joseph M. Univ Calif Riverside Dept Chem & Environm Engn Ctr Environm Res & Technol CE CERT Bourns Coll Engn Riverside CA 92521 USA Korea Adv Inst Sci & Technol Dept Chem & Biomol Engn Taejon 305701 South Korea Kunsan Natl Univ Dept Chem Engn Gunsan 573701 Jeonbuk South Korea Hyndai Engn Co Ltd Proc Plant Grp Seoul 158723 South Korea

Steam-methane reforming (SW) reaction was studied using a tubular reactor packed with NiO/gamma-Al2O3 catalyst to obtain synthesis gases with H-2/CO ratios optimal for the production of synthetic diesel fuel from steam-hydrogasification of carbonaceous materials. Pure CH4 and CH4-CO2 mixtures were used as reactants in the presence of steam. SMR runs were conducted at various operation parameters. Increasing temperature from 873 to 1,023 K decreased H CO ratio from 20 to 12. H-2/CO ratio decreased from 16 to 12 with pressure decreasing from 12.8 to 1.7 bars. H-2/CO ratio also decreased from about 11 to 7 with steam/CH4 ratio of feed decreasing from 5 to 2, the lowest limit to avoid severe coking. With pure CH4 as the feed, H-2/CO ratio of synthesis gas could not be lowered to the optimal range of 4-5 by adjusting the operation parameters;however, the limitation in optimizing the H-2/CO ratio for synthetic diesel fuel production Could be removed by introducing CO2 to CH4 feed to make CH4-CO2 mixtures. This effect can be primarily attributed to the contributions by CO2 reforming of CH4 as well as reverse water-gas shift reaction, which led to lower H-2/CO ratio for the synthesis gas. A simulation technique, ASPEN Plus, was applied to verify the consistency between experimental data and Simulation results. The model satisfactorily Simulated changes of H-2/CO ratio versus the operation parameters as well as the effect of CO2 addition to CH4 feed.

关键词： Steam-niethane Reforming operation parameters CO2 Addition to CH4 Feed ASPEN Simulator Optimal H-2/CO Ratio

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Selective reduction of highly concentrated nitrate by electrochemical method using a combination of Zn and Ti/Ir-Ru electrodes

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DESALINATION AND WATER TREATMENT 2017年 95卷 186-191页

作者： Cha, Ho Young Kweon, Ji Hyang Shin, Hyun-Gon Bae, Sungjun Park, Ki Young Konkuk Univ Dept Civil & Environm Syst Engn 120 Neungdong Ro Seoul 05029 South Korea Konkuk Univ Dept Environm Engn 120 Neungdong Ro Seoul 05029 South Korea Shinhan Univ Dept Energy & Environm Engn 40 Bulmadel Ro Dongducheon Si 11340 Gyeonggi Do South Korea

Treatment of wastewater contaminated by highly concentrated nitrate was studied by electrochemical method using a combination of Zn cathode and Ti/Ir-Ru anode in an undivided cell. We observed that almost 76% of initial nitrate (1,000 NO3--N mg/L) was removed in 8 h by electrodenitrification without significant production of undesirable by-products (i.e., nitrite and ammonia). Variations of pH and temperature were also monitored during the electrochemical nitrate reduction, which showed an increase in both pH (up to 12.5) and temperature (up to 41.5 degrees C), resulting in the enhanced nitrate reduction in this study. The nitrate removal efficiency increased (30% -> 76% -> 84%) as the current density increased (20 -> 40 -> 60 mA/cm(2)), but it was not a linear increase due to the increase of hydrogen evolution at high current density. The increase in paired electrode number from one to four led to the enhanced nitrate removal from 72% to 100% in 8 h reaction time. Moreover, we observed a remarkable increase in nitrate removal by using a combination of one anode and two cathodes (86% in 8 h) without productions of nitrite and ammonia due to the acceleration of nitrate reduction by increasing number of cathode.

关键词： Nitrate Electrochemical method Zn cathode Ti/Ir-Ru anode operation parameters

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λ operations on packet sets and the significance of application

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Journal of Convergence Information Technology 2012年第15期7卷 303-312页

作者： Fengchun, Liu Chunying, Zhang Ruitao, Liang Jing, Wang College of Science Hebei United University China

The packet sets introduced the dynamic characteristics into common sets, improving the limited common sets into a new structure and the model of mathematical. The packet sets is a collection of the form of the internal packet sets and the outer packet sets. Or (X F, X F) is packet sets. The packet sets is of dynamics features, as for the common sets can be intersection, union, differential, and other operations, but the packet sets is a promotion of the common sets. Using the dynamic features of the packet sets, and introduced the packet sets operation with the parameters λ (λ = 1,2,...,t), given the packet sets operation with parameters λ of the operation of complement, intersection, union, differential, and give the operation on the relationship theorem between this operation and common sets. By giving the example of the parameters λ of the operation on the packet sets to illustrate the practical significance of the operation, and further promote the application of the packet sets in dynamic information system.

关键词： The Packet Sets l operation Of The Packet Sets operation parameters

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Optimization of a cyclic activated sludge system for norfloxacin wastewater treatment under low-load conditions

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DESALINATION AND WATER TREATMENT 2022年 246卷 111-119页

作者： Gao, Jianlei Guo, Xianglong Yan, Yixin Liu, Yang Yue, Zhihao Zhu, Wanqiu Zhengzhou Univ Sch Ecol & Environm Zhengzhou 450001 Peoples R China Zhengzhou Univ Midea Real Estate Grp Co Ltd Zhengzhou 450001 Peoples R China

A sewage treatment station was used to treat the pharmaceutical intermediate wastewater of norfloxacin. The designed influent was 480 m(3) d(-1), but the actual influent was only 100 m(3) d(-1). Thus, the cyclic activated sludge system (CASS) was under low-load conditions, which demonstrated poor operation. In this experiment, the optimal operating parameters of the CASS under low-load conditions were studied by adjusting the inflow duration, return sludge ratio, aeration time, dissolved oxygen (DO) concentration, and mixed liquid volatile suspended solids (MLVSS) concentration to improve pollutant removal. The results showed that the optimal inflow duration was 4 h, the return sludge ratio was adjusted from 100% to 133%, the aeration time was 6 h, the DO concentration was adjusted from the designed parameter of 2.0 mg L-1 to the range of 2.8 similar to 3.0 mg L-1, and the MLVSS concentration was adjusted from the designed parameter of 2,500 mg L-1 to the range of 2,300 similar to 2,500 mg L-1. Under these optimal operating conditions, the entire effluent could meet the local indirect discharge standard of Henan Province. Furthermore, the guaranteed rate of the effluent reaching the standard exceeded 95%.

关键词： Cyclic activated sludge system Effluent water quality Guarantee rate Low-load conditions operation parameters Pharmaceutical wastewater

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