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Temporal evolution of charged and neutral nanoparticle concentrations during atmospheric new particle

E. Rohan Jayaratne, Buddhi Pushpawela, Lidia Morawska

《环境科学与工程前沿(英文)》 2016年 第10卷 第5期 doi: 10.1007/s11783-016-0862-x

摘要: Over 100 new particle formation events were studied. In 50 events, charged and neutral particles were not formed at the same time. In 42 of these events the charged particles formed before the neutral particles. Their subsequent growth rates were not determined by the particle charge. The result suggests that ion induced nucleation plays a role in particle formation. Time series of nanoparticle number concentration during new particle formation (NPF) events in the urban environment of Brisbane, Australia, showed that the formation of charged particles often occurred before that of neutral particles. We monitored 241 days during the calendar year 2012 over which NPF events were observed on 108 days. We studied the times at which the charged and neutral particle concentrations in the size range 1.8–3.2 nm reached their peak values and found that they were clearly different in 50 events with the peak neutral particle concentration lagging behind the charged particle concentration during 42 of these events with a mean time lag of 24±12 min. While the charged particles were more likely to form before the neutral particles, once formed, the growth rate of the particles did not depend on their charge. While ion-induced nucleation is not the dominant mechanism of NPF in the atmosphere, our observations suggest that the presence of ions in the atmosphere plays a role that cannot be ignored.

关键词: Charged particles     Cluster ions     Secondary particles     Environmental pollution    

Shear wall layout optimization of tall buildings using Quantum Charged System Search

Siamak TALATAHARI, Mahdi RABIEI

《结构与土木工程前沿(英文)》 2020年 第14卷 第5期   页码 1131-1151 doi: 10.1007/s11709-020-0660-1

摘要: This paper presents a developed meta-heuristic algorithm to optimize the shear walls of tall reinforced concrete buildings. These types of walls are considered as lateral resistant elements. In this paper, Quantum Charged System Search (QCSS) algorithm is presented as a new optimization method and used to improve the convergence capability of the original Charged System Search. The cost of tall building is taken as the objective function. Since the design of the lateral system plays a major role in the performance of the tall buildings, this paper proposes a unique computational technique that, unlike available works, focuses on structural efficiency or architectural design. This technique considers both structural and architectural requirements such as minimum structural costs, torsional effects, flexural and shear resistance, lateral deflection, openings and accessibility. The robustness of the new algorithm is demonstrated by comparing the outcomes of the QCSS with those of its standard algorithm.

关键词: Quantum Charged System Search     shear wall     layout optimization     tall buildings    

Ductility loss of hydrogen-charged and releasing 304L steel

Yanfei WANG, Jianming GONG, Yong JIANG, Wenchun JIANG, Wang JIANG

《机械工程前沿(英文)》 2013年 第8卷 第3期   页码 298-304 doi: 10.1007/s11465-013-0265-7

摘要:

The mechanical properties and fracture behavior of 304L austenitic stainless steel after cathodic hydrogen charging and hydrogen spontaneously releasing are investigated by tensile tests. Flat tensile specimens were cathodic hydrogen charged at various current densities. For each density, two specimens were charged at the same condition. When the charging process completed, one specimen was tensile immediately to fracture and the other was aged to release the hydrogen out of it and then was also tensile to fracture. The resulting tensile properties and micrographs of fracture surfaces of these specimens were evaluated and compared. The results show ductility loss occurred in the hydrogen-charged specimens and the loss increased as the current density increasing. After hydrogen releasing, the specimens recovered a certain extent but not all of its original ductility. Scanning electron microscope (SEM) micrographs of fracture surfaces reveal that irreversible damage had developed in the hydrogen-releasing specimens during the releasing process rather than the charging process. This consequence can be ascribed to the high tensile stress caused by non-uniform hydrogen distribution during hydrogen releasing.

关键词: hydrogen embrittlement     ductility loss     hydrogen releasing     control strategy     304L austenitic stainless steel    

Effect of electrokinetic property of charged polyether sulfone membrane on bovine serum albumin fouling

Xiaorong Meng, Shanshan Huo, Lei Wang, Xudong Wang, Yongtao Lv, Weiting Tang, Rui Miao, Danxi Huang

《环境科学与工程前沿(英文)》 2017年 第11卷 第2期 doi: 10.1007/s11783-017-0907-9

摘要: Negatively charged CMPES and positively charged QAPES membranes were fabricated. Charge modification reduced the adhesion forces between PES UF membranes and BSA. QAPES-BSA / was weaker than that of CMPES-BSA at pH 3 and on the contrary at pH 9. Flux decline rate was positively correlated with the adhesion forces of membrane-BSA. Variation of adhesion was consistent with that of potential absolute values. Negatively charged carboxymethylated polyethersulfone (CMPES) and positively charged quaternized polyethersulfone (QAPES) ultrafiltration (UF) membranes were prepared by bulk chemical modification and non-solvent induced phase separation method. The effects of PES membrane interfacial electrokinetic property on the bovine serum albumin (BSA) membrane fouling behavior were studied with the aid of the membrane-modified colloidal atomic force microscopy (AFM) probe. Electrokinetic test results indicated that the streaming potential (D ) of QAPES membrane was not consistent with its expected value, however, within the pH range of 3–10, the potentials of two charged-modified PES membranes were more stable than the unmodified membrane. When pH value was 3, 4.7 or 9, the interaction behavior between charged PES membrane and BSA showed that there was significant linear correlation between the jump distance of membrane-BSA adhesion force ( ) and the potential absolute value. Charged modification significantly reduced the adhesion of PES membrane-BSA, and the adhesion data was good linear correlated with the flux decline rate in BSA filtration process, especially reflected in the CMPES membrane. The above experimental facts proved that the charged membrane interfacial electric double layer structure and its electrokinetic property had strong ties with the protein membrane fouling behavior.

关键词: Charged PES UF membrane     BSA     Electrokinetic characterization     Adhesion force     Jump distance    

Combustion and emission characteristics of a turbo-charged common rail diesel engine fuelled with diesel-biodiesel-DEE

Ni ZHANG, Zuohua HUANG, Xiangang WANG, Bin ZHENG

《能源前沿(英文)》 2011年 第5卷 第1期   页码 104-114 doi: 10.1007/s11708-011-0138-x

摘要: The combustion and emission characteristics of a turbo-charged, common rail diesel engine fuelled with diesel-biodiesel-DEE blends were investigated. The study reports that the brake-specific fuel consumption of diesel-biodiesel-DEE blends increases with increase of oxygenated fuel fractions in the blends. Brake thermal efficiency shows little variation when operating on different diesel-biodiesel-DEE blends. At a low load, the NO emission of the diesel-biodiesel-DEE blends exhibits little variation in comparison with the biodiesel fraction. The NO emission slightly increases with increase in the biodiesel fraction in diesel-biodiesel-DEE blends at medium load. However, the NO emission increases remarkably with increase of the biodiesel fraction at high load. Particle mass concentration decreases significantly with increase of the oxygenated-fuels fraction at all engine speeds and loads; particle number concentration decreases remarkably with increase of the oxygenated-fuels fraction. HC and CO emissions decrease with increasing oxygenated-fuels fraction in these blends.

关键词: Combustion     particulate emissions     diesel-biodiesel-DEE blend     diesel engine    

Calculation of collision frequency function for aerosol particles in free molecule regime in presence

Xiaowei LUO, Yannick BENICHOU, Suyuan YU

《能源前沿(英文)》 2013年 第7卷 第4期   页码 506-510 doi: 10.1007/s11708-013-0275-5

摘要: The collision frequency function for aerosol particles has already been calculated for the free molecule regime and for the continuum range. The present work, taking into account the influence of internal force fields such as magnetic force, electric force and molecular forces, created by particles themselves, recalculated the collision frequency in the case of particles much smaller than the mean free path of the gas (free molecule regime). Attractive forces increase naturally the collision frequency, while repulsive forces decrease it. The calculation was performed for all types of central forces deriving from a potential, including Coulomb forces and Van der Waals forces.

关键词: aerosol particles     collision frequency function     coagulation    

Polymer-nanoinorganic particles composite membranes: a brief overview

Zhen-liang XU, Li-yun YU, Ling-feng HAN

《化学科学与工程前沿(英文)》 2009年 第3卷 第3期   页码 318-329 doi: 10.1007/s11705-009-0199-0

摘要: Polymer-nanoinorganic particles composite membranes present an interesting approach for improving the physical and chemical, as well as separation properties of polymer membranes, because they possess characteristics of both organic and inorganic membranes such as good permeability, selectivity, mechanical strength, thermal stability and so on. The preparations and structures of polymer-nanoinorganic particles composite membranes and their unique properties are reviewed.

关键词: polymer     nanoinorganic particles     composite membranes    

Transparent exopolymer particles (TEPs)-associated protobiofilm: A neglected contributor to biofouling

《环境科学与工程前沿(英文)》 2021年 第15卷 第4期 doi: 10.1007/s11783-020-1361-7

摘要:

• Bacteria could easily and quickly attached onto TEP to form protobiofilms.

关键词: Transparent exopolymer particles (TEPs)     TEP-protobiofilm     Bacteria attachment     Biofouling of membrane    

Dynamic characteristics of molten droplets and hot particles falling in liquid pool

Liangxing LI, Weimin MA, Huixiong LI, Tingkuan CHEN,

《能源前沿(英文)》 2010年 第4卷 第2期   页码 246-251 doi: 10.1007/s11708-009-0077-y

摘要: The dynamic characteristics of molten droplets and hot particles at the very beginning of their fall into coolant pools are presented. The falling course of a single droplet or a single hot particle was recorded by a high-speed camera and a curve of velocity . time was obtained. Emphasis was placed on the effects of the droplet’s size and temperature, the coolant’s temperature and properties, and the droplet’s physical properties on the moving behavior. The results for the all cases showed that the velocity of a falling droplet/particle decreased rapidly but rebounded shortly, at the beginning of droplet/particle falling in the coolant. Following such a V-shaped evolution in velocity, the droplet/particle slows down gradually to a comparatively steady velocity. An increase in either coolant temperature or droplet temperature results in a larger velocity variation in the “J-region”, but a smaller deceleration when it moves out of the “J-region”. The elevated volatility of a coolant leads to a steeper deceleration in the “J-region” and beyond. The bigger size of a particle leads to a greater velocity variation in the “J-region” and terminal velocity. A high melting point and thermal conductivity as well as lower heat capacity contribute to dramatic variation in the “J-region” and low terminal velocity.

关键词: dynamic characteristics     molten droplets     high-temperature particles     fuel and coolant interactions    

Selective removal of phenol by spherical particles of

Qingchuan CHEN, Yicun WEN, Yu CANG, Li LI, Xuhong GUO, Rui ZHANG

《化学科学与工程前沿(英文)》 2013年 第7卷 第2期   页码 162-169 doi: 10.1007/s11705-013-1318-5

摘要: Spherical particles of -, - and -cyclodextrin (CD) polymers to efficiently remove phenol from waste water were prepared by reverse suspension polymerization with epichlorohydrin as crosslinker in liquid paraffin. By controlling the amounts of crosslinker and water, well-defined spherical polymer particles with controllable size were obtained. Due to the selective inclusion associations between CD groups and phenol, these CD spherical polymer particles were demonstrated to be ideal candidates for removal of phenol. Among them -CD polymer particles showed the best performance. The kinetics and isothermal equilibrium models were used to fit the experimental data of phenol removal from aqueous solution using these CD polymer particles. It was found that the kinetics followed the Ho and Mckay equation, suggesting that the adsorption process of phenol was controlled by diffusion and the host-guest interaction between CD and phenol. Equilibrium isothermal data can be well fitted by the Freundlich equation. The negative free energy change indicated the spontaneous nature of adsorption of phenol by -, - and -CD spherical polymer particles, while the lowest free energy for -CD polymer reflected its best adsorption ability, compared to - and -CD polymer particles.

关键词: cyclodextrin polymer particles     phenol     kinetic models     adsorption isotherm equilibrium models    

Characteristics and mixing state of S-rich particles in haze episodes in Beijing

Jun Hu, Fengkui Duan, Kebin He, Yongliang Ma, Shuping Dong, Xiande Liu

《环境科学与工程前沿(英文)》 2016年 第10卷 第5期 doi: 10.1007/s11783-016-0861-y

摘要: Four types of S-rich particles are identified by SEM/FESEM-EDX With on-line observation, characteristics of S-rich particles are discovered Intensities of formation of S-rich particles are seasonally different Direct individual analysis using Scanning Electron Microscopy combined with online observation was conducted to examine the S-rich particles in PM of two typical polluted haze episodes in summer and winter from 2014 to 2015 in Beijing. Four major types of S-rich particles, including secondary CaSO particles (mainly observed in summer), S-rich mineral particles (SRM), S-rich water droplets (SRW) and (C, O, S)-rich particles (COS) were identified. We found the different typical morphologies and element distributions of S-rich particles and considered that (C, O, S)-rich particles had two major mixing states in different seasons. On the basis of the S-rich particles’ relative abundances, S concentrations and their relationships with PM as well as the seasonal comparison, we revealed that the S-participated formation degrees of SRM and SRW would enhance with increasing PM concentration. Moreover, C-rich matter and sulfate had seasonally different but significant impacts on the formation of COS.

关键词: S-rich particles     Morphology     Element distribution     Mixing state    

Fundamental influences of particles on stirred and unstirred venting processes of foaming systems

Henrik LEIMEISTER,Jörg STEINBACH

《化学科学与工程前沿(英文)》 2014年 第8卷 第2期   页码 141-148 doi: 10.1007/s11705-014-1423-0

摘要: Venting is the common safety measure to protect plant equipment against excessive overpressure. So far, scenarios in which particles were part of the system and should have been accounted for did ignore their presence; the scenarios were treated like a two-phase system. Current research shows that particles can have a major influence on the venting behaviour. Experimental results indicate that particles affect level swell and relief flow especially of foamy systems. Based on those results four different layers of influence of the particle have been identified and are presented in a first model. Based on this model recommendations for the development of new and more complex models are given.

关键词: venting     multi-phase    

Hygroscopicity of ambient submicron particles in urban Hangzhou, China

Jiachen ZHANG, Lin WANG, Jianmin CHEN, Shengmao FENG, Jiandong SHEN, Li JIAO

《环境科学与工程前沿(英文)》 2011年 第5卷 第3期   页码 342-347 doi: 10.1007/s11783-011-0358-7

摘要: In this study, hygroscopicity of size-segregated ambient submicron particles in urban Hangzhou was studied from 28th December 2009 to 18th January 2010, using a hygroscopicity-tandem differential mobility analyzer (H-TDMA). The submicron particles in Hangzhou showed a minor hygroscopic growth at 73% relative humidity (RH), and then grew significantly between 77% and 82% RH. Monomodal distribution accounted for 90% for 30 nm particles, 17% for 50 nm particles, and less than 7% for particles larger than 50 nm at 82% RH. Deconvolution of the bimodal distribution indicated a less hygroscopic group and a more hygroscopic group, with the fraction of the more hygroscopic group increasing with the initial dry particle size and then remaining almost constant for accumulation mode particles. Our results imply that submicron particles in urban Hangzhou were almost entirely externally mixed, and the hygroscopic properties of ambient particles in urban Hangzhou were mainly a function of their size and chemical composition.

关键词: hygroscopicity     hygroscopic tandem differential mobility analyzer (H-TDMA)     submicron ambient particles     Hangzhou    

Collaborative control of fine particles and ozone required in China for health benefit

《环境科学与工程前沿(英文)》 2023年 第17卷 第8期 doi: 10.1007/s11783-023-1692-2

摘要:

● Increased DAAO offsets 3/4 of the decrease of DAAP in 2013–2020.

关键词: Excess deaths     Long-term exposure     Fine particle     Ozone    

Effects of seed particles Al

Xiao Zhang, Biwu Chu, Junhua Li, Chaozhi Zhang

《环境科学与工程前沿(英文)》 2017年 第11卷 第4期 doi: 10.1007/s11783-017-0936-4

摘要: Seed particles Al O , Al (SO ) and H SO were selected to investigate their effects on secondary aerosol (SA) formation in toluene/NO photooxidation under sulfur dioxide (SO ) and ammonia (NH ). Effect of seed particles on SA formation was related to their acid-base properties and the presence of acid or alkaline gases. Under NH -poor condition, SA formation increased with increasing SO concentration due to the acid-catalyzing effect of the oxidation products of SO (i.e. H SO ). The enhancing effect of SO became unobvious under NH -rich condition, because NH would eliminate the acid-catalyzing effect by neutralizing the acid products. Acidic seeds H SO accelerated SA formation under either SO or NH condition. Weak acidic Al (SO ) seeds didn’t affect obviously on SA formation. The inhibiting effect of amphoteric seeds Al O on SA formation was related to the presence of SO / NH due to their acid-base property. Under NH -poor condition, the inhibiting effect of Al O on SA formation decreased with increasing concentration of SO , while under NH -rich condition, the inhibiting effect wasn’t remarkable.

关键词: Seed particle     Secondary aerosol     Sulfur dioxide     Ammonia     Acid-catalyzing effect    

标题 作者 时间 类型 操作

Temporal evolution of charged and neutral nanoparticle concentrations during atmospheric new particle

E. Rohan Jayaratne, Buddhi Pushpawela, Lidia Morawska

期刊论文

Shear wall layout optimization of tall buildings using Quantum Charged System Search

Siamak TALATAHARI, Mahdi RABIEI

期刊论文

Ductility loss of hydrogen-charged and releasing 304L steel

Yanfei WANG, Jianming GONG, Yong JIANG, Wenchun JIANG, Wang JIANG

期刊论文

Effect of electrokinetic property of charged polyether sulfone membrane on bovine serum albumin fouling

Xiaorong Meng, Shanshan Huo, Lei Wang, Xudong Wang, Yongtao Lv, Weiting Tang, Rui Miao, Danxi Huang

期刊论文

Combustion and emission characteristics of a turbo-charged common rail diesel engine fuelled with diesel-biodiesel-DEE

Ni ZHANG, Zuohua HUANG, Xiangang WANG, Bin ZHENG

期刊论文

Calculation of collision frequency function for aerosol particles in free molecule regime in presence

Xiaowei LUO, Yannick BENICHOU, Suyuan YU

期刊论文

Polymer-nanoinorganic particles composite membranes: a brief overview

Zhen-liang XU, Li-yun YU, Ling-feng HAN

期刊论文

Transparent exopolymer particles (TEPs)-associated protobiofilm: A neglected contributor to biofouling

期刊论文

Dynamic characteristics of molten droplets and hot particles falling in liquid pool

Liangxing LI, Weimin MA, Huixiong LI, Tingkuan CHEN,

期刊论文

Selective removal of phenol by spherical particles of

Qingchuan CHEN, Yicun WEN, Yu CANG, Li LI, Xuhong GUO, Rui ZHANG

期刊论文

Characteristics and mixing state of S-rich particles in haze episodes in Beijing

Jun Hu, Fengkui Duan, Kebin He, Yongliang Ma, Shuping Dong, Xiande Liu

期刊论文

Fundamental influences of particles on stirred and unstirred venting processes of foaming systems

Henrik LEIMEISTER,Jörg STEINBACH

期刊论文

Hygroscopicity of ambient submicron particles in urban Hangzhou, China

Jiachen ZHANG, Lin WANG, Jianmin CHEN, Shengmao FENG, Jiandong SHEN, Li JIAO

期刊论文

Collaborative control of fine particles and ozone required in China for health benefit

期刊论文

Effects of seed particles Al

Xiao Zhang, Biwu Chu, Junhua Li, Chaozhi Zhang

期刊论文