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Mercury enrichment in

Chunhao Dai, Pufeng Qin, Zhangwei Wang, Jian Chen, Xianshan Zhang, Si Luo

《环境科学与工程前沿（英文）》 2017年第11卷第1期 doi: 10.1007/s11783-017-0892-z

摘要： Mercury enrichment in response to elevated atmospheric mercury concentrations in the organs of rape ( ) was investigated. Elevated soil mercury content had significant impact on mercury accumulation in rape stems, roots, seeds and seed coats. Leaf mercury in the leaves was mostly affected by atmospheric input while the stems were mostly affected by soil concentrations. Mercury in the aboveground plant tissue mainly derived from atmospheric absorption, and atmospheric mercury absorption in leaves was higher than that in the stems. Mercury enrichment in response to elevated atmospheric mercury concentrations in the organs of rape ( ) was investigated using an open top chamber fumigation experiment and a soil mercury enriched cultivation experiment. Results indicate that the mercury concentration in leaves and stems showed a significant variation under different concentrations of mercury in atmospheric and soil experiments while the concentration of mercury in roots, seeds and seed coats showed no significant variation under different atmospheric mercury concentrations. Using the function relation established by the experiment, results for atmospheric mercury sources in rape field biomass showed that atmospheric sources accounted for at least 81.81% of mercury in rape leaves and 32.29% of mercury in the stems. Therefore, mercury in the aboveground biomass predominantly derives from the absorption of atmospheric mercury.

关键词： Open top chamber Gaseous elemental mercury (GEM) Soil Mercury Brassica napus

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Development of a fan-stirred constant volume combustion chamber and turbulence measurement with PIV

《能源前沿（英文）》 2022年第16卷第6期页码 973-987 doi: 10.1007/s11708-021-0762-z

摘要： A fan-stirred combustion chamber is deve-loped for spherically expanding flames, with P and T up to 10 bar and 473 K, respectively. Turbulence characteristics are estimated using particle image velocimetry (PIV) at different initial pressures (P = 0.5–5 bar), fan frequencies (ω = 0–2000 r/min), and impeller diameters (D = 100 and 114 mm). The flame propagation of methanol/air is investigated at different turbulence intensities (u′=0–1.77 m/s) and equivalence ratios (φ = 0.7–1.5). The results show that u′ is independent of P and proportional to ω, which can be up to 3.5 m/s at 2000 r/min. L_T is independent of P and performs a power regression with ω approximately. The turbulent field is homogeneous and isotropic in the central region of the chamber while the inertial subrange of spatial energy spectrum is more collapsed to –5/3 law at a high Re_T. Compared to laminar expanding flames, the morpho-logy of turbulent expanding flames is wrinkled and the wrinkles will be finer with the growth of turbulence intensity, consistent with the decline of the Taylor scale and the Kolmogorov scale. The determined S_L in the present study is in good agreement with that of previous literature. The S_L and S_T of methanol/air have a non-monotonic trend with φ while peak S_T is shifted to the richer side compared to S_L. This indicates that the newly built turbulent combustion chamber is reliable for further experimental study.

关键词： fan-stirred combustion chamber turbulence characteristics particle image velocimetry (PIV) methanol turbulent expanding flames

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Atmospheric heterogeneous reaction of chlorobenzene on mineral -FeO particulates: a chamber experiment

《环境科学与工程前沿（英文）》 2023年第17卷第11期 doi: 10.1007/s11783-023-1734-9

摘要：

● Photochemical conversion of chlorobenzene (CB) on α-Fe₂O₃ was evaluated.

关键词： Photochemical conversion Chlorobenzene α-Fe₂O₃ PCDD/Fs Mineral particulate

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Pre-chamber turbulent jet ignition of methane/air mixtures with multiple orifices in a large bore constantvolume chamber: effect of air-fuel equivalence ratio and pre-mixed pressure

Xiang LI, Wenzheng ZHANG, Zhong HUANG, Dehao JU, Li HUANG, Mingzhi FENG, Xingcai LU, Zhen HUANG

《能源前沿（英文）》 2019年第13卷第3期页码 483-493 doi: 10.1007/s11708-019-0631-1

摘要： Liquefied natural gas (LNG), mainly composed of methane, is in progress to substitute diesel fuel in heavy-duty marine engine for practical, economic, and environmental considerations. However, natural gas is relatively difficult to be ignited in a large bore combustion chamber. A combustion enhancement technique called pre-chamber turbulent jet ignition (TJI) can permit combustion and flame propagation in a large-bore volume. To investigate the effect of air-fuel equivalence ratio and pre-mixed pressure on pre-chamber TJI of methane/air mixtures with multiple orifices in a large bore volume, experimental tests and computational simulations were implemented to study the discharge of hot turbulent jets from six orifices of the pre-chamber. Different initial pressures and air-fuel equivalence ratios were considered to analyze the characteristics of TJI. The asymmetry of the turbulent jet actuated from six different orifices were found due to the asymmetric orientation of the spark plug, resulting in the inhomogeneous distribution of combustion in the constant volume chamber, which should be considered seriously in the marine engine design. Besides, as the premixed pressure increases, it has more effect on the flame propagation and plays a more important role, as it further increases.

关键词： marine engine natural gas methane turbulent jet ignition (TJI) pre-chamber

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Design and analyses of open-ended pipe piles in cohesionless soils

Yuan GUO,Xiong (Bill) YU

《结构与土木工程前沿（英文）》 2016年第10卷第1期页码 22-29 doi: 10.1007/s11709-016-0314-5

摘要： Large open-ended pipe pile has been found to be advantageous for use in transportation projects. The current design method, however, is not adequately developed. To close this practice gap, this paper first summarized different design methods for open-ended pipe piles in sandy soils. A major factor for all the design codes is to properly account for the formation and effects of soil plug. The comparison indicates that there is a large variation in the base capacity evaluation among different methods due to the complex behaviors of soil plug. To close the knowledge gap, discrete element method (DEM) was used to simulate the soil plugging process and provide insight on the plugging mechanism. The simulation results show that the arching effect significantly increases the internal unit shear resistance along pipe piles. The porosity distribution and particle contact force distribution from DEM model indicate a large stress concentration occurs at the bottom of the soil plug. Besides, nearly 90% of the plug resistance is provided by the bottom half portion of the soil column. The soil-pile friction coefficient has a significant effect on the magnitude of plug resistance, with the major transition occurred for friction coefficient between 0.3 and 0.4.

关键词： open-ended pipe pile soil plug DEM base capacity

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A novel flow electrode capacitive deionization device with spindle-shaped desalting chamber

《环境科学与工程前沿（英文）》 2023年第18卷第4期 doi: 10.1007/s11783-024-1800-y

摘要：

● A spindle-shaped influent chamber was designed and equipped in FCDI system.

关键词： Spindle-shaped chamber Desalination performance Flow electrode capacitive deionization

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Thermal response of steel framing members in open car park fires

Xia YAN; Marion CHARLIER; Thomas GERNAY

《结构与土木工程前沿（英文）》 2022年第16卷第9期页码 1071-1088 doi: 10.1007/s11709-022-0879-0

摘要： For open car park structures, adopting a performance-based structural fire design is often justified and allowed because the fire does not reach flashover. However, this design approach requires an accurate assessment of temperatures in structural members exposed to car fires. This paper describes a numerical study on the thermal exposure on steel framing members in open car park fires. Steel temperatures are computed by the coupling of computational fluid dynamics and finite element modeling, and by analytical models from the Eurocodes. In addition, the influence of galvanization on the steel temperature evolution is assessed. Results show that temperatures in unprotected beams and columns are influenced by the section geometry, car fire scenario, modeling approach, and use of galvanization. Galvanization slightly delays and reduces peak temperature. Regarding the different models, CFD-FEM (CFD: computational fluid dynamics, FEM: finite-element method) coupled models predict lower temperatures than the Hasemi model, because the latter conservatively assumes that the fire flame continuously touches the ceiling. Further, the Hasemi model cannot account for the effect of reduced emissivity from galvanization on the absorbed heat flux. Detailed temperature distributions obtained in the steel members can be used to complete efficient structural fire designs based on the member sections, structure layout, and use of galvanization.

关键词： open car park localized fire steel frame numerical modeling computational fluid dynamics

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Two-dimensional modeling of sintering of a powder layer on top of nonporous substrate

Tiebing CHEN, Yuwen ZHANG,

《机械工程前沿（英文）》 2010年第5卷第2期页码 143-148 doi: 10.1007/s11465-010-0006-0

摘要： Selective laser sintering (SLS) of a two-component metal powder layer on the top of multiple sintered layers by a moving Gaussian laser beam is modeled. The loose metal powder layer is composed of a powder mixture with significantly different melting points. The physical model that accounts the shrinkage induced by melting is described by using a temperature-transforming model. The effects of the porosity and the thickness of the atop loose powder layer with different numbers of the existing sintered metal powder layers below on the sintering process are numerically investigated. The present work will provide a better understanding to simulate much more complicated three-dimensional SLS process.

关键词： laser sintering melting solidification heat transfer

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The most influential “Top 10 Events” in carbon neutrality and climate change in 2022

《能源前沿（英文）》 2023年第17卷第1期页码 1-4 doi: 10.1007/s11708-023-0869-5

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NC flame pipe cutting machine tool based on open architecture CNC system

Xiaogen NIE, Yanbing LIU

《机械工程前沿（英文）》 2009年第4卷第2期页码 147-152 doi: 10.1007/s11465-009-0025-x

摘要： Based on the analysis of the principle and flame movement of a pipe cutting machine tool, a retrofit NC flame pipe cutting machine tool (NFPCM) that can meet the demands of cutting various pipes is proposed. The paper deals with the design and implementation of an open architecture CNC system for the NFPCM, many of whose aspects are similar to milling machines; however, different from their machining processes and control strategies. The paper emphasizes on the NC system structure and the method for directly creating the NC file according to the cutting type and parameters. Further, the paper develops the program and sets up the open and module NC system.

关键词： flame pipe cutting flame incision tracks CNC open architecture CNC system

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Cavitation in semi-open centrifugal impellers for a miniature pump

LUO Xianwu, LIU Shuhong, ZHANG Yao, XU Hongyuan

《能源前沿（英文）》 2008年第2卷第1期页码 31-35 doi: 10.1007/s11708-008-0011-8

摘要： Cavitation in miniature pumps was investigated experimentally for two semi-open centrifugal impellers. Although both impellers had the same blade cross-section, one impeller had a two-dimensional blade, while the other had a leaned blade. The flows were also analyzed using a numerical model of the three-dimensional turbulent flow in the pumps near the peak efficiency point using the -? turbulence model and the VOF cavitation model. The average cavitation performance of each impeller was satisfactorily predicted by the numerical simulations. The results show that the miniature pumps have similar cavitation performances as an ordinary-size pump, with the cavitation performance of the semi-open impeller reduced by increased axial tip clearances. Also, both the hydraulic and cavitation performance of the semi-open impeller were improved by the leaned blade. The results also show that uniform flow upstream of the impeller inlet will improve the cavitation performance of a miniature pump.

关键词： cavitation performance semi-open impeller increased two-dimensional efficiency

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Analysis of catchment evapotranspiration at different scales using bottom-up and top-down approaches

Xiangyu XU, Dawen YANG,

《结构与土木工程前沿（英文）》 2010年第4卷第1期页码 65-77 doi: 10.1007/s11709-010-0002-9

摘要： Physically-based hydrological models are used to predict catchment water balance through detailed simulation of hydrological processes at small temporal and spatial scales. However, annual catchment water balance can also be easily and simply predicted using lumped conceptual model. Comparison between physically-based hydrological models and lumped conceptual models can help us understand the dominant factors on catchment water balance at different scales. In this paper, a distributed physically-based hydrological model (i.e., bottom-up approach) and a simple water-energy balance model (i.e., top-down approach) are used to predict actual evapotranspiration in nine sub-catchments, and the whole basin of the Luan River in northern China. Both simulations give very close values of annual evapotranspiration and show the same complementary relationship between actual and potential evapotranspiration at annual time scale. From the analysis at different time scales through comparison of the top-down and the bottom-up methods, it is shown that the annual catchment evapotranspiration is controlled mainly by annual precipitation and potential evapotranspiration, and the variability of soil water and vegetation becomes more important at a smaller time scale in the study areas. It is also known that the relationship between potential and actual evapotranspiration shows a highly nonlinear relationship at the annual and catchment scale but can be simplified to a linear relationship at hourly temporal and hillslope scales, which is commonly used in the physically-based hydrological models.

关键词： catchment evapotranspiration distributed hydrological model water-energy balance model top-down and bottom-up approaches

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Evaluation of the harmonic scalpel in open surgery for abdominal aortic aneurysm

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《医学前沿（英文）》 2012年第6卷第1期页码 85-88 doi: 10.1007/s11684-012-0174-x

摘要：

The harmonic scalpel is a hemostatic device primarily designed for use in laparoscopic surgery. During the last few years, many surgeons have begun to use the harmonic scalpel in open surgery. Several papers have cited the benefits of the device compared with conventional knot-tying techniques; however, no evidence showing the advantages of using the harmonic scalpel in complicated abdominal aortic aneurysm (AAA) surgery has been presented. The aim of the present study is to determine the value of the harmonic scalpel in open operation for AAA. A total of 153 patients who underwent open surgery for AAA at the Department of Vascular Surgery of Guangdong General Hospital, China between January 2001 and December 2010, were retrospectively analyzed. Open surgery performed with the harmonic scalpel on 105 patients was compared with open operation using conventional knot-tying techniques on 48 patients. The operative time, intraoperative blood loss, total postoperative drainage fluid volumes, hospital stay, and postoperative complications between the two groups were compared. The harmonic scalpel group was associated with a shorter operation time (113.2±23.6 min vs. 232.1±39.2 min, P<0.01) and lower intraoperative blood loss (126.1±96.6 ml vs. 592.1±207.2 ml, P<0.01). Postoperative drainage fluid volumes were greater in the conventional surgery group than in the harmonic scalpel group (702.1±192.8 ml vs. 198.5±97.4 ml, P<0.01). The hospital stay was shorter for the harmonic scalpel group than for the conventional surgery group (10.7±3.3 d vs. 16.5±4.7 d, P<0.05). No differences between the postoperative complications or hospital mortality of the two groups were found. The harmonic scalpel is a safe and minimally invasive tool in open surgery for AAA and is associated with shorter operative time, shorter hospital stay, and lower intraoperative blood loss and postoperative drainage fluid volumes compared with conventional knot-tying techniques.

关键词： abdominal aortic aneurysm harmonic scalpel minimally invasive

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Experimental study on flow behavior at open channel confluences

WANG Xiekang, WANG Xianye, LU Weizhen, LIU Tonghuan

《结构与土木工程前沿（英文）》 2007年第1卷第2期页码 211-216 doi: 10.1007/s11709-007-0025-z

摘要： Channel confluences are common in natural rivers and hydraulic engineering, and the flow behavior at confluences becomes very complex because of the interaction between the tributary and the main river. In this study, the experiments were performed in a combined flume with a 30º angle between the main and tributary flume located at Sichuan University. The velocity was measured by using a three-component acoustic Doppler velocimeter (ADV) over a grid defined throughout the junction region. Based on the analysis of the velocity at the confluence, the distinctive characteristics of a channel confluence flow may be divided into several zones including a zone of separation immediately downstream of the junction branch channel, the maximum and minimum velocity regions at the upstream and downstream in the confluent channel, and a shear plane developed between the two combining flows downstream of the confluent channel. In addition, secondary circulations in different directions at the higher and lower velocity zones are observed as well.

关键词： ADV different interaction separation downstream

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Effects of inner sleeves on the inner frictional resistance of open-ended piles driven into sand

Janaka J. KUMARA,Yoshiaki KIKUCHI,Takashi KURASHINA,Takahiro YAJIMA

《结构与土木工程前沿（英文）》 2016年第10卷第4期页码 499-505 doi: 10.1007/s11709-016-0335-0

摘要： In open-ended piles, inner friction is developed between inner pile shaft and the inner soil. Inner frictional resistance depends largely on the degree of soil plugging, which is influenced by many factors including pile diameter, relative density and end conditions of piles. In this paper, effects of inner sleeves on inner frictional resistance are discussed. The experiments were conducted on a medium-dense sandy ground using laboratory-scale piles. It was observed that the piles penetrated under partially-plugged or unplugged state. The results suggest that inner frictional resistance, increases with sleeve height, linearly and requires 2 ( is pile outer diameter) of to produce a large as 50% of by ( is total resistance). The results also indicate that bearing capacity increases with wall thickness at the pile tip, which can be attributed to the increase in annular area. The results also indicate that soil plug height is independent of sleeve height. The results also reveal that the penetration of straight piles is closer to unplugged state than the sleeved piles. The results of incremental filling ratio and plug length ratio also indicate that the degree of soil plugging is affected by the sleeve height.

关键词： bearing capacity inner frictional resistance inner sleeve open-ended piles soil plugging

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标题作者时间类型操作

Mercury enrichment in

Chunhao Dai, Pufeng Qin, Zhangwei Wang, Jian Chen, Xianshan Zhang, Si Luo

期刊论文

Development of a fan-stirred constant volume combustion chamber and turbulence measurement with PIV

期刊论文

Atmospheric heterogeneous reaction of chlorobenzene on mineral -FeO particulates: a chamber experiment

期刊论文

Pre-chamber turbulent jet ignition of methane/air mixtures with multiple orifices in a large bore constantvolume chamber: effect of air-fuel equivalence ratio and pre-mixed pressure

Xiang LI, Wenzheng ZHANG, Zhong HUANG, Dehao JU, Li HUANG, Mingzhi FENG, Xingcai LU, Zhen HUANG

期刊论文

Design and analyses of open-ended pipe piles in cohesionless soils

Yuan GUO,Xiong (Bill) YU

期刊论文

A novel flow electrode capacitive deionization device with spindle-shaped desalting chamber

期刊论文

Thermal response of steel framing members in open car park fires

Xia YAN; Marion CHARLIER; Thomas GERNAY

期刊论文

Two-dimensional modeling of sintering of a powder layer on top of nonporous substrate

Tiebing CHEN, Yuwen ZHANG,