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Impact of food to microorganism ratio and alcohol ethoxylate dosage on methane production in treatment

Yulun Nie, Xike Tian, Zhaoxin Zhou, Yu-You Li

《环境科学与工程前沿（英文）》 2017年 第11卷 第6期 doi: 10.1007/s11783-017-0947-1

摘要： The effects of food to microorganism (F/M) ratio and alcohol ethoxylate (AE) dosage on the methane production potential were investigated in treatment of low-strength wastewater by a submerged anaerobic membrane bioreactor (SAnMBR). The fate of AE and its acute and/or chronic impact on the anaerobic microbes were also analyzed. The results indicated that AE had an inhibitory effect to methane production potential (lag-time depends on the AE dosage) and the negative effect attenuated subsequently and methane production could recover at F/M ratio of 0.088–0.357. VFA measurement proved that AE was degraded into small molecular organic acids and then converted into methane at lower F/M ratio (F/M<0.158). After long-term acclimation, anaerobic microbe could cope with the stress of AE by producing more EPS (extracellular polymeric substances) and SMP (soluble microbial products) due to its self-protection behavior and then enhance its tolerance ability. However, the methane production potential was considerably decreased when AE was present in wastewater at a higher F/M ratio of 1.054. Higher AE amount and F/M ratio may destroy the cell structure of microbe, which lead to the decrease of methane production activity of sludge and methane production potential.

关键词： Anaerobic membrane bioreactor AnMBR     F/M ratio     Surfactant     Wastewater     Methane production     Influence    

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Nonlinear dynamics of a wind turbine tower

IANNUZZO, F. PENTA, M. MONACO

《机械工程前沿（英文）》 2019年 第14卷 第3期   页码 342-350 doi: 10.1007/s11465-019-0524-3

摘要： The recent proliferation of wind turbines has revealed problems in their vulnerability under different site conditions, as evidenced by recent collapses of wind towers after severe actions. Analyses of structures subjected to variable actions can be conducted through several methods with different accuracy levels. Nonlinear dynamics is the most reliable among such methods. This study develops a numerical procedure to obtain approximate solutions for rigid-plastic responses of structures subjected to base harmonic pulses. The procedure’s model is applied to a wind turbine tower subjected to inertial forces generated by harmonic ground acceleration, and failure is assumed to depend on the formation of shear hinges. The proposed approach provides an efficient representation of the post-elastic behavior of the structure, has a low computational cost and high effectiveness, and uses a limited number of mechanical parameters.

关键词： nonlinear dynamics     plastic shear failure     modal approximation     time history    

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Investigation of wind energy potentials in Brunei Darussalam

M. A. SALAM, M. G. YAZDANI, Q. M. RAHMAN, Dk NURUL, S. F. MEI, Syeed HASAN

《能源前沿（英文）》 2019年 第13卷 第4期   页码 731-741 doi: 10.1007/s11708-018-0528-4

摘要： Conventional power generation mainly depends on natural gas and diesel oil in Brunei Darussalam. The power utility company is now thinking of power generation using natural wind. In this paper, wind energy, being one of the most readily available renewable energy sources, was studied. The wind characteristic, velocity and directions were studied using Weibull distribution based on the measurement of wind speed at two different locations in Brunei Darussalam. These wind speed distributions were modeled using the Wind Power program. The wind rose graph was obtained for the wind direction to analyze the wind power density onshore and offshore. Based on this analysis, it has been found that the wind speed of 3 to 5 m/s has a probability of occurrence of 40%. Besides, the annual energy production at a wind speed of 5 m/s has been found to be in the range between 1000 and 1500 kWh for both the locations in Brunei Darussalam.

关键词： wind speed     Weibull distribution     wind rose     wind energy     wind power    

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Best operating conditions to produce hydroxyapatite nanoparticles by means of a spinning disc reactor

F. D’ Intino,B. de Caprariis,M.L. Santarelli,N. Verdone,A. Chianese

《化学科学与工程前沿（英文）》 2014年 第8卷 第2期   页码 156-160 doi: 10.1007/s11705-014-1427-9

摘要： In this work, Mg doped hydroxyapatite (Mg-HAP) nanoparticles were produced by a reaction-precipitation process by using a spinning disc reactor (SDR) at high rotational speed. The production process of these nanoparticles consisted of the neutralization reaction between two aqueous solutions of calcium chloride and ammonia orthophosphate at room temperature. By operating at pH= 10, a high purity Mg-HAP nanoparticles were obtained. In particular, they were 51 nm in average size when the two reagents were fed over the disc symmetrically at 3 cm from the disc center and a rotational speed of the disc reactor equal to 1400 r/min was adopted.

关键词： hydroxyapatite     nanoparticles     spinning disc reactor    

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图像水印框架的层级-方向分解分析 Article

M. F. KAZEMI,M. A. POURMINA,A. H. MAZINAN

《信息与电子工程前沿（英文）》 2016年 第17卷 第11期   页码 1199-1217 doi: 10.1631/FITEE.1500165

摘要： 通过一组模拟攻击，基于峰值信噪比（peak signal-to-noise ratio）、结构相似度（structural similarity）等指标评估其性能。

关键词： 层级-方向分解分析；水印框架；轮廓小波嵌入表达；扰码模块；模拟攻击    

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An investigation of reaction furnace temperatures and sulfur recovery

ASADI, M. PAKIZEH, M. POURAFSHARI CHENAR

《化学科学与工程前沿（英文）》 2011年 第5卷 第3期   页码 362-371 doi: 10.1007/s11705-011-1106-z

摘要： In a modern day sulfur recovery unit (SRU), hydrogen sulfide (H S) is converted to elemental sulfur using a modified Claus unit. A process simulator called TSWEET has been used to consider the Claus process. The effect of the H S concentration, the H S/CO ratio, the input air flow rate, the acid gas flow of the acid gas (AG) splitter and the temperature of the acid gas feed at three different oxygen concentrations (in the air input) on the main burner temperature have been studied. Also the effects of the tail gas ratio and the catalytic bed type on the sulfur recovery were studied. The bed temperatures were optimized in order to enhance the sulfur recovery for a given acid gas feed and air input. Initially when the fraction of AG splitter flow to the main burner was increased, the temperature of the main burner increased to a maximum but then decreased sharply when the flow fraction was further increased; this was true for all three concentrations of oxygen. However, if three other parameters (the concentration of H S, the ratio H S/CO and the flow rate of air) were increased, the temperature of the main burner increased monotonically. This increase had different slopes depending on the oxygen concentration in the input air. But, by increasing the temperature of the acid gas feed, the temperature of the main burner decreased. In general, the concentration of oxygen in the input air into the Claus unit had little effect on the temperature of the main burner (This is true for all parameters). The optimal catalytic bed temperature, tail gas ratio and type of catalytic bed were also determined and these conditions are a minimum temperature of 300°C, a ratio of 2.0 and a hydrolysing Claus bed.

关键词： Claus unit     concentration of H2S     tail gas ratio     sulfur recovery     catalytic bed    

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Integrating space and time: a case for phenological context in grazing studies and management

Dawn M. BROWNING, Sheri SPIEGAL, Richard E. ESTELL, Andres F. CIBILS, Raul H. PEINETTI

《农业科学与工程前沿（英文）》 2018年 第5卷 第1期   页码 44-56 doi: 10.15302/J-FASE-2017193

摘要： In water-limited landscapes, patterns in primary production are highly variable across space and time. Livestock grazing is a common agricultural practice worldwide and a concern is localized overuse of specific pasture resources that can exacerbate grass losses and soil erosion. On a research ranch in New Mexico with average annual rainfall of 217 mm, we demonstrate with a quantitative approach that annual seasons vary greatly and examine foraging patterns in Angus-Hereford ( ) cows. We define five seasonal stages based on MODIS NDVI: pre-greenup, greenup, peak green, drydown and dormant, and examine livestock movements in 2008. Daily distance traveled by cows was greater and foraging area expanded during periods with higher precipitation. A regression model including minimum NDVI, rainfall and their interaction explained 81% of the seasonal variation in distance traveled by cows ( <0.01). Cows explored about 81 ha·d while foraging, but tended to explore smaller areas as the pasture became greener (greenup and peak green stages). Cows foraged an average of 9.7 h daily and spent more time foraging with more concentrated search patterns as pastures became greener. Our findings suggest that phenological context can expand the capacity to compare and integrate findings, and facilitate meta-analyses of grazing studies conducted at different locations and times of year.

关键词： GPS collars     Jornada Experimental Range     land-surface phenology     livestock movement     LTAR     MODIS NDVI     rangeland    

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Increasing the performance of anaerobic digestion: Pilot scale experimental study for thermal hydrolysis of mixed sludge

PEREZ-ELVIRA, M. FDZ-POLANCO, F. FDZ-POLANCO,

《环境科学与工程前沿（英文）》 2010年 第4卷 第2期   页码 135-141 doi: 10.1007/s11783-010-0024-5

摘要： The performance of a pilot plant operation combining thermal hydrolysis (170°C, 30 min) and anaerobic digestion (AD) was studied, determining the main properties for samples of fresh mixed sludge, hydrolyzed sludge, and digested sludge, in order to quantify the thermal pretreatment performance (disintegration, solubilisation, and dewaterability) and its impact on the anaerobic digestion performance (biodegradability, volatile solids reduction, and digester rheology) and end product characteristics (dewaterability, sanitation, organic and nitrogen content). The disintegration achieved during the thermal treatment enhances the sludge centrifugation, allowing a 70% higher total solids concentration in the feed to anaerobic digestion. The digestion of this sludge generates 40% more biogas in half the time, due to the higher solids removal compared to a conventional digester. The waste generated can be dewatered by centrifugation to 7% dry solids without polymer addition, and is pathogen free.

关键词： anaerobic digestion (AD)     biogas     performance     sludge     thermal hydrolysis    

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Common biases in client involved decision-making in the AEC industry

Sujesh F. SUJAN, Arto KIVINIEMI, Steve W. JONES, Jacqueline M. WHEATHCROFT, Eilif HJELSETH

《工程管理前沿（英文）》 2019年 第6卷 第2期   页码 221-238 doi: 10.1007/s42524-019-0026-3

摘要： Understanding of the constitution of client involved decisions is important for future improvements of the processes. Significant decisions in construction projects are reliant on heuristic processes where assumptions are developed from past experience. The paper presents a methodology to collect empirical data in an unstructured manner utilizing participant intuition and experience regarding project level collaboration, a term easily understood by practitioners. Empirical data collected from 6 focus group discussions in Norway and 18 individual interviews in Finland is associated with biases in decision making aimed at bridging the gap of understanding and literature’s insufficient coverage. An analytic framework was developed to suit the diverse emergence of concepts to allow application of psychological principles in a structured manner to empirical data. The paper contributes by identifying types of cognitive and motivational biases in client involved decisions. The biases are found to be alleviated by one another depending on the particular application of the decision. Findings suggest that normative beliefs exist developed from past experience and habitual thinking. A number of emerged biases in this domain are alleviated from normative beliefs which are discussed in this paper.

关键词： collaboration     construction industry     social science     decision-making     client     cognitive bias     motivational bias     holistic analysis     human factor    

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Bamboo-like -doped carbon nanotubes encapsulating M(Co, Fe)-Ni alloy for electrochemical production of

《化学科学与工程前沿（英文）》 2022年 第16卷 第4期   页码 498-510 doi: 10.1007/s11705-021-2082-6

摘要： The electrochemical conversion of CO2-H2O into CO-H2 using renewable energy is a promising technique for clean syngas production. Low-cost electrocatalysts to produce tunable syngas with a potential-independent CO/H2 ratio are highly desired. Herein, a series of N-doped carbon nanotubes encapsulating binary alloy nanoparticles (MxNi-NCNT, M= Fe, Co) were successfully fabricated through the co-pyrolysis of melamine and metal precursors. The MxNi-NCNT samples exhibited bamboo-like nanotubular structures with a large specific surface area and high degree of graphitization. Their electrocatalytic performance for syngas production can be tuned by changing the alloy compositions and modifying the electronic structure of the carbon nanotube through the encapsulated metal nanoparticles. Consequently, syngas with a wide range of CO/H2 ratios, from 0.5:1 to 3.4:1, can be produced on MxNi-NCNT. More importantly, stable CO/H2 ratios of 2:1 and 1.5:1, corresponding to the ratio to produce biofuels by syngas fermentation, could be realized on Co1Ni-NCNT and Co2Ni-NCNT, respectively, over a potential window of –0.8 to –1.2 V versus the reversible hydrogen electrode. Our work provides an approach to develop low-cost and potential-independent electrocatalysts to effectively produce syngas with an adjustable CO/H2 ratio from electrochemical CO2 reduction.

关键词： electrochemical reduction of CO2     syngas     N-doped carbon nanotubes     encapsulated alloy nanoparticles     CO/H2 ratio    

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全氟化碳乳剂19F磁共振成像的最新进展 Review

Wickline,Gregory M. Lanza

《工程（英文）》 2015年 第1卷 第4期   页码 475-489 doi: 10.15302/J-ENG-2015103

摘要：

19F磁共振成像(MRI) 的研究可追溯到30多年前。多年来，由于各种原因，对19F成像技术的研究进展缓慢。但是在过去的十年间，尤其是最近几年，19F成像的研究和临床相关性呈爆发式发展。部分原因归结为MRI仪器、19F/1H线圈设计以及临床前和临床核磁共振仪的超高速脉冲序列的发展。这些成就再加上对解剖生理学分子成像技术的兴趣以及一批创新造影剂的出现使19F的概念进入了早期的临床评估中。

关键词： 氟     磁共振成像(MRI)     双调线圈     全氟化碳     血管生成术     细胞标记    

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油压极值比与极值比效率

齐茂林

《中国工程科学》 2001年 第3卷 第4期   页码 73-75

摘要：

文章应用基础公式，推导液压系统油压极值比与极值比效率之间的关系式。该式说明，油压极值比越大，极值比效率就越低。提出了油压极值比是可以设计和选择的。

关键词： 油压极值比     极值比效率     液压系统    

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Pressure drop analysis on the positive half-cell of a cerium redox flow battery using computational fluid dynamics: Mathematical and modelling aspects of porous media

Fernando F. Rivera, Berenice Miranda-Alcántara, Germán Orozco, Carlos Ponce de León, Luis F. Arenas

《化学科学与工程前沿（英文）》 2021年 第15卷 第2期   页码 399-409 doi: 10.1007/s11705-020-1934-9

摘要： Description of electrolyte fluid dynamics in the electrode compartments by mathematical models can be a powerful tool in the development of redox flow batteries (RFBs) and other electrochemical reactors. In order to determine their predictive capability, turbulent Reynolds-averaged Navier-Stokes (RANS) and free flow plus porous media (Brinkman) models were applied to compute local fluid velocities taking place in a rectangular channel electrochemical flow cell used as the positive half-cell of a cerium-based RFB for laboratory studies. Two different platinized titanium electrodes were considered, a plate plus a turbulence promoter and an expanded metal mesh. Calculated pressure drop was validated against experimental data obtained with typical cerium electrolytes. It was found that the pressure drop values were better described by the RANS approach, whereas the validity of Brinkman equations was strongly dependent on porosity and permeability values of the porous media.

关键词： CFD simulation     porous media     porous electrode     pressure drop     redox flow battery    

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Development of soft kernel durum wheat

Craig F. MORRIS

《农业科学与工程前沿（英文）》 2019年 第6卷 第3期   页码 273-278 doi: 10.15302/J-FASE-2019259

摘要：

Kernel texture (grain hardness) is a fundamental and determining factor related to wheat ( spp.) milling, baking and flour utilization. There are three kernel texture classes in wheat: soft and hard hexaploid ( ), and very hard durum ( subsp. ). The genetic basis for these three classes lies with the Puroindoline genes. Phenotypically, the easiest means of quantifying kernel texture is with the Single Kernel Characterization System (SKCS), although other means are valid and can provide fundamental material properties. Typical SKCS values for soft wheat would be around 25 and for durum wheat≥80. Soft kernel durum wheat was created via homeologous recombination using the mutation, which facilitated the transfer of ca. 28 Mbp of 5DS that replaced ca. 21 Mbp of 5BS. The 5DS translocation contained a complete and intact locus and both puroindoline genes. Expression of the puroindoline genes in durum grain resulted in kernel texture and flour milling characteristics nearly identical to that of soft wheat, with high yields of break and straight-grade flours, which had small particle size and low starch damage. Dough water absorption was markedly reduced compared to durum flour and semolina. Dough was essentially unchanged and reflected the inherent gluten properties of the durum background. Pasta quality was essentially equal-to-or-better than pasta made from semolina. Agronomically, soft durum germplasm showed good potential with moderate grain yield and resistance to a number of fungal pathogens and insects. Future breeding efforts will no doubt further improve the quality and competitiveness of soft durum cultivars.

关键词： soft durum wheat     grain hardness     puroindolines     milling     baking     pasta     noodles    

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Controlling interstory drift ratio profiles via topology optimization strategies

《结构与土木工程前沿（英文）》 2023年 第17卷 第2期   页码 165-178 doi: 10.1007/s11709-022-0892-3

摘要： An approach to control the profiles of interstory drift ratios along the height of building structures via topology optimization is proposed herein. The theoretical foundation of the proposed approach involves solving a min–max optimization problem to suppress the maximum interstory drift ratio among all stories. Two formulations are suggested: one inherits the bound formulation and the other utilizes a p-norm function to aggregate all individual interstory drift ratios. The proposed methodology can shape the interstory drift ratio profiles into inverted triangular or quadratic patterns because it realizes profile control using a group of shape weight coefficients. The proposed formulations are validated via a series of numerical examples. The disparity between the two formulations is clear. The optimization results show the optimal structural features for controlling the interstory drift ratios under different requirements.

关键词： interstory drift ratio     aggregation function     bound formulation     min–max problem     topology optimization    

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标题 作者 时间 类型 操作

Impact of food to microorganism ratio and alcohol ethoxylate dosage on methane production in treatment

Yulun Nie, Xike Tian, Zhaoxin Zhou, Yu-You Li

期刊论文

Nonlinear dynamics of a wind turbine tower

IANNUZZO, F. PENTA, M. MONACO

期刊论文

Investigation of wind energy potentials in Brunei Darussalam

M. A. SALAM, M. G. YAZDANI, Q. M. RAHMAN, Dk NURUL, S. F. MEI, Syeed HASAN

期刊论文

Best operating conditions to produce hydroxyapatite nanoparticles by means of a spinning disc reactor

F. D’ Intino,B. de Caprariis,M.L. Santarelli,N. Verdone,A. Chianese

期刊论文

图像水印框架的层级-方向分解分析

M. F. KAZEMI,M. A. POURMINA,A. H. MAZINAN

期刊论文

An investigation of reaction furnace temperatures and sulfur recovery

ASADI, M. PAKIZEH, M. POURAFSHARI CHENAR

期刊论文

Integrating space and time: a case for phenological context in grazing studies and management

Dawn M. BROWNING, Sheri SPIEGAL, Richard E. ESTELL, Andres F. CIBILS, Raul H. PEINETTI

期刊论文

Increasing the performance of anaerobic digestion: Pilot scale experimental study for thermal hydrolysis of mixed sludge

PEREZ-ELVIRA, M. FDZ-POLANCO, F. FDZ-POLANCO,

期刊论文

Common biases in client involved decision-making in the AEC industry

Sujesh F. SUJAN, Arto KIVINIEMI, Steve W. JONES, Jacqueline M. WHEATHCROFT, Eilif HJELSETH

期刊论文

Bamboo-like -doped carbon nanotubes encapsulating M(Co, Fe)-Ni alloy for electrochemical production of

期刊论文

全氟化碳乳剂19F磁共振成像的最新进展

Wickline,Gregory M. Lanza

期刊论文

油压极值比与极值比效率

齐茂林

期刊论文

Pressure drop analysis on the positive half-cell of a cerium redox flow battery using computational fluid dynamics: Mathematical and modelling aspects of porous media

Fernando F. Rivera, Berenice Miranda-Alcántara, Germán Orozco, Carlos Ponce de León, Luis F. Arenas

期刊论文

Development of soft kernel durum wheat

Craig F. MORRIS

期刊论文

Controlling interstory drift ratio profiles via topology optimization strategies

期刊论文