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The size distribution of airborne bacteria and human pathogenic bacteria in a commercial composting plant

《环境科学与工程前沿(英文)》 2021年 第15卷 第3期 doi: 10.1007/s11783-020-1356-4

摘要:

•Bacterial concentrations from eight stages were 104–105copies/m3.

关键词: Size distribution     Airborne bacteria     Biological diversity     Human pathogenic bacteria     Composting plants    

Particle size distribution and shape control of Au nanoparticles used for particle gun

S. Kida, M. Ichiji, J. Watanabe, I. Hirasawa

《化学科学与工程前沿(英文)》 2013年 第7卷 第1期   页码 60-64 doi: 10.1007/s11705-013-1313-x

摘要: Au nanoparticles are expected for the media to transfer genes into plants. However, the control of particle size distribution (PSD) and shape of Au nanoparticles is too difficult to design and prepare particles with suitable quality for the gene supporting media. Reduction crystallization experiments were performed in aqueous solution in order to clarify the effect of feeding conditions such as feeding profile, feeding rate, and feeding amount on PSD and shape of Au nanoparticles. Ascorbic acid (AsA) was selected as a reducing agent because it is safe for plants. Au particles of 50 nm, 50–200 nm, and 150–400 nm were obtained in batch operation, single-jet, and double-jet, respectively. Moreover, in single-jet and double-jet, the mean size of the obtained Au particles increases with the decrease of feeding rate or the increase of feeding amount. It is concluded that PSD of Au nanoparticles can be controlled in the range of 50–400 nm by changing feeding conditions of AsA and HAuCl aqueous solution.

关键词: reduction crystallization     particle size distribution     gene transferring media    

Soot size distribution in lightly sooting premixed flames of benzene and toluene

Wang LIU, Jiaqi ZHAI, Baiyang LIN, He LIN, Dong HAN

《能源前沿(英文)》 2020年 第14卷 第1期   页码 18-26 doi: 10.1007/s11708-020-0663-6

摘要: The evolution of particle size distribution function (PSDF) of soot in premixed flames of benzene and toluene was studied on a burner stabilized stagnation (BSS) flame platform. The cold gas velocities were changed to hold the maximum flame temperatures of different flames approximately constant. The PSDFs of all the test flames exhibited a bimodal distribution, i.e., a small-size nucleation mode and a large-size accumulation mode. It was observed that soot nucleation and particle growth in the benzene flame were stronger than those in the toluene flame at short residence times. At longer residence times, the PSDFs of the two flames were similar, and the toluene flame showed a larger particle size distribution range and a higher particle volume fraction than the benzene flame.

关键词: premixed flame     soot     particle size distribution function     benzene     toluene    

A comparative study of particle size distribution from two oxygenated fuels and diesel fuel

Xiaoyan SHI, Kebin HE, Jie ZHANG, Yongliang MA, Yunshan GE, Jianwei TAN,

《环境科学与工程前沿(英文)》 2010年 第4卷 第1期   页码 30-34 doi: 10.1007/s11783-010-0011-x

摘要: Oxygenated fuels are known to reduce particulate matter (PM) emissions from diesel engines. In this study, 100% soy methyl ester (SME) biodiesel fuel (B100) and a blend of 10% acetal denoted by A-diesel with diesel fuel were tested as oxygenated fuels. Particle size and number distributions from a diesel engine fueled with oxygenated fuels and base diesel fuel were measured using an Electrical Low Pressure Impactor (ELPI). Measurements were made at ten steady-state operational modes of various loads at two engine speeds. It was found that the geometric mean diameters of particles from SME and A-diesel were lower than that from base diesel fuel. Compared to diesel fuel, SME emitted more ultra-fine particles at rated speed while emitting less ultra-fine particles at maximum speed. Ultra-fine particle number concentrations of A-diesel were much higher than those of base diesel fuel at most test modes.

关键词: oxygenated fuel     diesel particulate matter     particle size distribution     biofuel    

火灾标准火烟雾颗粒测量及粒径尺度分布函数研究

疏学明,郑魁,袁宏永,姚斌

《中国工程科学》 2005年 第7卷 第8期   页码 51-55

摘要:

烟雾是火灾探测的重要参量,烟雾颗粒粒径及其尺度分布直接影响到感烟探测器的灵敏度,而目前有关烟雾颗粒粒径的研究相当匮乏。采用扫描迁移率粒子测量仪对火灾标准火烟雾颗粒的粒径大小及其分布进行实验测量,并采用数学拟合方法系统研究了烟雾颗粒粒径分布函数,研究结果表明对数正态分布函数较好地描述了烟雾颗粒尺度分布特征,其结论有益于火灾探测基础研究的发展。

关键词: 烟雾     颗粒     粒径     分布函数    

Structure creation in earthen construction materials: information from dry soil mixtures

Christopher BECKETT, Charles AUGARDE

《结构与土木工程前沿(英文)》 2011年 第5卷 第2期   页码 151-159 doi: 10.1007/s11709-011-0109-7

摘要: There is increasing interest in the use of earthen construction materials, such as rammed earth, due to their inherent sustainability. These materials have been used by man for thousands of years and some of the earliest examples can be found in China. Features of the structures of these materials arise from the means of production. In particular, in situ earthen construction materials exhibit strong anisotropy due to their layered nature. A more subtle structure effect arises from the way that the earth mixture is deposited. This paper reviews and discusses stratification effects in dry soil mixtures, including some original experimental work, and indicates some links between the features of the dry mixtures and earthen construction materials. Improved understanding of the physical processes in play will allow more accurate specification of these materials in the future, and hence spread their use.

关键词: rammed earth     stratification     particle size distribution     pore size distribution    

A spectrometer for measuring particle size distributions in the range of 3 nm to 10 μm

Jieqiong LIU,Jingkun JIANG,Qiang ZHANG,Jianguo DENG,Jiming HAO

《环境科学与工程前沿(英文)》 2016年 第10卷 第1期   页码 63-72 doi: 10.1007/s11783-014-0754-x

摘要: A spectrometer combining electrical mobility sizing and aerodynamic sizing was developed to measure aerosol size distributions in the range of 3 nm to 10 μm. It includes three instruments which cover different size ranges (a nano scanning mobility particle sizer (NSMPS, 3 – 60 nm), a regular scanning mobility particle sizer (RSMPS, 40 – 700 nm), and an aerodynamic particle sizer (APS, 550 nm – 10 μm)). High voltage and sheath flow of the NSMPS and RSMPS were supplied using two home-built control boxes. A LabVIEW program was developed for spectrometer automatic operation. A linear inversion method was applied to correct particle multiple charging effects and to integrate data from the three instruments into a wide-range size distribution. Experiments were conducted to compare distributions in the overlap size ranges measured by three instruments. Good agreement between the NSMPS and RSMPS was achieved after correcting for the difference in counting efficiencies of the two particle counters. Aerodynamic size distributions reported by the APS were converted to mobility size distributions by applying an effective density method. Distributions measured by the RSMPS and APS were consistent in the overlap size range of 550 – 700 nm. A full spectrum in the size range of 3 nm to 10 μm was demonstrated by measuring aerosol generated using a mixture of different sized polystyrene latex spheres.

关键词: spectrometer     particle size distribution     electrical mobility     linear inversion     aerodynamic diameter    

Size-controlled green synthesis of silver nanoparticles assisted by L-cysteine

Wenchao Zhang,Lin Zhang,Yan Sun

《化学科学与工程前沿(英文)》 2015年 第9卷 第4期   页码 494-500 doi: 10.1007/s11705-015-1527-1

摘要: A green and size-controlled synthesis of silver nanoparticles (Ag NPs) in aqueous solution with the assistance of L-cysteine is presented. The size of Ag NPs decreases with the increase of L-cysteine concentration, and thus can be controlled by adjusting L-cysteine concentration. TEM analysis shows that Ag NPs with an average size of 3 nm can be produced in the presence of 1.0 mmol/L L-cysteine, about one sixth of the size of Ag NPs obtained in the absence of L-cysteine (17 nm). The as-synthesized silver colloidal solution is stable and can be stored at room temperature for at least two months without any precipitation. This L-cysteine assisted method is simple, feasible and efficient, and would facilitate the production and application of Ag NPs.

关键词: nanoparticles     silver     L-cysteine     size distribution     synthesis    

PM10 emissions from industrial coal-fired chain-grate boilers

Xinghua Li, Junzan Han, Lei Duan

《环境科学与工程前沿(英文)》 2017年 第11卷 第6期 doi: 10.1007/s11783-017-0966-y

摘要: Industrial coal-fired boiler is an important air pollutant emission source in China. The chain-grate boiler is the most extensively used type of industrial coal-fired boiler. An electrical low-pressure impactor, and a Dekati Low Pressure Impactor were applied to determine mass and number size distributions of PM at the inlet and the outlet of the particulate emission control devices at six coal-fired chain-grate boilers. The mass size distribution of PM generated from coal-fired chain-grate boilers generally displays a bimodal distribution that contains a submicron mode and a coarse mode. The PM in the submicron mode for burning with raw coal contributes to 33%±10 % of PM emissions, much higher than those for pulverized boilers. And the PM in the submicron mode for burning with briquette contributes up to 86 % of PM emissions. Multiclones and scrubbers are not efficient for controlling PM emission. Their average collection efficiencies for sub-micron particle and super-micron particle are 34% and 78%, respectively. Operating conditions of industrial steam boilers have influence on PM generation. Peak of the submicron mode during normal operation period is larger than the start-up period.

关键词: coal-fired chain-grate boiler     PM10     size distribution     particulate emission control devices     size-dependent collection efficiency    

Simulation of bubble column reactors using CFD coupled with a population balance model

Tiefeng WANG

《化学科学与工程前沿(英文)》 2011年 第5卷 第2期   页码 162-172 doi: 10.1007/s11705-009-0267-5

摘要: Bubble columns are widely used in chemical and biochemical processes due to their excellent mass and heat transfer characteristics and simple construction. However, their fundamental hydrodynamic behaviors, which are essential for reactor scale-up and design, are still not fully understood. To develop design tools for engineering purposes, much research has been carried out in the area of computational fluid dynamics (CFD) modeling and simulation of gas-liquid flows. Due to the importance of the bubble behavior, the bubble size distribution must be considered in the CFD models. The population balance model (PBM) is an effective approach to predict the bubble size distribution, and great efforts have been made in recent years to couple the PBM into CFD simulations. This article gives a selective review of the modeling and simulation of bubble column reactors using CFD coupled with PBM. Bubble breakup and coalescence models due to different mechanisms are discussed. It is shown that the CFD-PBM coupled model with proper bubble breakup and coalescence models and interphase force formulations has the ability of predicting the complex hydrodynamics in different flow regimes and, thus, provides a unified description of both the homogeneous and heterogeneous regimes. Further study is needed to improve the models of bubble coalescence and breakup, turbulence modification in high gas holdup, and interphase forces of bubble swarms.

关键词: bubble column     computational fluid dynamics     bubble breakup and coalescence     population balance model     bubble size distribution    

A novel light fluctuation spectrum method for in-line particle sizing

Shouxuan QIN, Xiaoshu CAI, Li MA

《能源前沿(英文)》 2012年 第6卷 第1期   页码 89-97 doi: 10.1007/s11708-012-0176-z

摘要: This paper discusses two problems in in-line particle sizing when using light fluctuation method. First, by retrieving the ratio of particle concentrations at different time, the intensity of incident light is obtained. There exists narrow error between the calculated and pre-detected value of the intensity of incident light. Secondly, by combining spectrum analysis with Gregory’s theory, a multi-sub-size zone model is proposed, with which the relationship between the distribution of turbidity and the particle size distribution (PSD) can be established, and an algorithm developed to determine the distribution of turbidity. Experiments conducted in the laboratory indicate that the measured size distribution of pulverized coal conforms well with the imaging result.

关键词: in-line measurement     particle size distribution (PSD)     incident light intensity     particle concentration     light fluctuation    

Synthesis and characterization of magnesium hydroxide by batch reaction crystallization

Xingfu SONG, Shuying SUN, Dengke ZHANG, Jin WANG, Jianguo YU

《化学科学与工程前沿(英文)》 2011年 第5卷 第4期   页码 416-421 doi: 10.1007/s11705-011-1125-9

摘要: Magnesium hydroxide with high purity and uniform particle size distribution was synthesized by the direct precipitation method using MgCl and NaOH as reactive materials and NaCl as additive to improve the crystallization behavior of the product. The particle size distribution, crystal phase, morphology, and surface area of magnesium hydroxide were characterized by Malvern laser particle size analyzer, X-ray diffraction (XRD), scanning electron microscope (SEM) and Branauer-Emmett-Teller (BET) method, respectively. The purity of products was analyzed by the chemical method. The effects of synthesis conditions on the particle size distribution and water content (filtration cake) of magnesium hydroxide were investigated. The results indicated that feeding mode and rate, and reaction temperature had important effects on water content and the particle size distribution of the product, and sodium chloride improved the crystallization behavior of magnesium hydroxide. The ball-like magnesium hydroxides with the particle size distribution of 6.0–30.0 μm and purity higher than 99.0% were obtained. This simple and mild synthesis method was promising to be scaled up for the industrial production of magnesium hydroxide.

关键词: magnesium hydroxide     direct precipitation method     industrial crystallization     particle size distribution    

A better way to do small-for-size liver transplantation in rats

null

《医学前沿(英文)》 2011年 第5卷 第1期   页码 106-110 doi: 10.1007/s11684-011-0113-2

摘要:

Establishing a model for small-for-size liver transplantation is the basis for this study of partial and living donor graft liver transplantation. This study aims to explore a simpler and more effective way of establishing a 30% small-for-size liver transplantation in rats. Sprague-Dawley rats were selected as the donors and recipients. Small-for-size orthotopic liver transplantation was performed using Kamada’s two-cuff method. The donor’s liver was flushed via the abdominal aorta and hepatectomy was performed in situ. The animals were divided into three groups depending on the graft selected, with 40 pairs of rats in each group. In group I, the median lobe of the liver was used as graft; in group II, the right half of the median lobe and the right lobe were used as graft; and in group III, the median and right lobes were used as graft. In groups I and II, the bodyweights of donors were the same as those of recipients; however, in group III the bodyweights of donors were 100–120 g less than those of the recipients. The duration needed for transplantation, the 7-day survival rates, and the technical complication rates were compared among these three groups. The time required for hepatectomy was shorter in group III compared with groups I and II (8.8?±?0.7 min vs. 11.5?±?1.1 min and 10.1?±?1.0 min, P = 0.001). The cold ischemia time for the grafts, the anhepatic times, and the transplantation times for the recipients were not significantly different among the three groups. Compared with groups I and II, the incidence of bleeding, bile leakage, and inferior vena caval strictures were significantly decreased in group III (P<0.05). No significant differences between the three groups were found based on other complications after the operation (P>0.05). Group III had better 7-day survival rates and longer median survival times but the differences were not statistically significant. The method of small for donor bodyweight using the median and right lobes for grafting may be a more effective and simpler way of establishing a 30% small-for-size liver transplantation in rats, as shown by the shorter hepatectomy time and the occurrence of fewer complications after the operation.

关键词: liver transplantation     small-for-size     rats    

Effect of Cu-ZSM-5 catalysts with different CuO particle size on selective catalytic oxidation of N,N-Dimethylformamide

《环境科学与工程前沿(英文)》 2022年 第16卷 第10期 doi: 10.1007/s11783-022-1557-0

摘要:

● A series of Cu-ZSM-5 catalysts were tested for DMF selective catalytic oxidation.

关键词: N     N-Dimethylformamide     Selective catalytic oxidation     Cu-ZSM-5     CuO particle size    

Influence of surface cracking, anchor head profile, and anchor head size on cast-in headed anchors in

《结构与土木工程前沿(英文)》   页码 1163-1187 doi: 10.1007/s11709-023-0987-5

摘要: In this study, the concrete cone capacity, concrete cone angle, and load–displacement response of cast-in headed anchors in geopolymer concrete are explored using numerical analyses. The concrete damaged plasticity (CDP) model in ABAQUS is used to simulate the behavior of concrete substrates. The tensile behavior of anchors in geopolymer concrete is compared with that in normal concrete as well as that predicted by the linear fracture mechanics (LFM) and concrete capacity design (CCD) models. The results show that the capacity of the anchors in geopolymer concrete is 30%–40% lower than that in normal concrete. The results also indicate that the CCD model overestimates the capacity of the anchors in geopolymer concrete, whereas the LFM model provides a much more conservative prediction. The extent of the difference between the predictions by the numerical analysis and those of the above prediction models depends on the effective embedment depth of the anchor and the anchor head size. The influence of concrete surface cracking on the capacity of the anchor is shown to depend on the location of the crack and the effective embedment depth. The influence of the anchor head profile on the tensile capacity of the anchors is found to be insignificant.

关键词: cast-in anchor     concrete cone capacity     geopolymer concrete     head size     surface crack     anchor profile    

标题 作者 时间 类型 操作

The size distribution of airborne bacteria and human pathogenic bacteria in a commercial composting plant

期刊论文

Particle size distribution and shape control of Au nanoparticles used for particle gun

S. Kida, M. Ichiji, J. Watanabe, I. Hirasawa

期刊论文

Soot size distribution in lightly sooting premixed flames of benzene and toluene

Wang LIU, Jiaqi ZHAI, Baiyang LIN, He LIN, Dong HAN

期刊论文

A comparative study of particle size distribution from two oxygenated fuels and diesel fuel

Xiaoyan SHI, Kebin HE, Jie ZHANG, Yongliang MA, Yunshan GE, Jianwei TAN,

期刊论文

火灾标准火烟雾颗粒测量及粒径尺度分布函数研究

疏学明,郑魁,袁宏永,姚斌

期刊论文

Structure creation in earthen construction materials: information from dry soil mixtures

Christopher BECKETT, Charles AUGARDE

期刊论文

A spectrometer for measuring particle size distributions in the range of 3 nm to 10 μm

Jieqiong LIU,Jingkun JIANG,Qiang ZHANG,Jianguo DENG,Jiming HAO

期刊论文

Size-controlled green synthesis of silver nanoparticles assisted by L-cysteine

Wenchao Zhang,Lin Zhang,Yan Sun

期刊论文

PM10 emissions from industrial coal-fired chain-grate boilers

Xinghua Li, Junzan Han, Lei Duan

期刊论文

Simulation of bubble column reactors using CFD coupled with a population balance model

Tiefeng WANG

期刊论文

A novel light fluctuation spectrum method for in-line particle sizing

Shouxuan QIN, Xiaoshu CAI, Li MA

期刊论文

Synthesis and characterization of magnesium hydroxide by batch reaction crystallization

Xingfu SONG, Shuying SUN, Dengke ZHANG, Jin WANG, Jianguo YU

期刊论文

A better way to do small-for-size liver transplantation in rats

null

期刊论文

Effect of Cu-ZSM-5 catalysts with different CuO particle size on selective catalytic oxidation of N,N-Dimethylformamide

期刊论文

Influence of surface cracking, anchor head profile, and anchor head size on cast-in headed anchors in

期刊论文