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Effect of streambed substrate on macroinvertebrate biodiversity

DUAN Xuehua, WANG Zhaoyin, TIAN Shimin

《环境科学与工程前沿(英文)》 2008年 第2卷 第1期   页码 122-128 doi: 10.1007/s11783-008-0023-y

摘要: Macroinvertebrates are important components of stream ecosystems, and are often used as indicator species for the assessment of river ecology. Numerous studies have shown that substrate is the primary physical environmental variable affecting the taxa richness and density of macroinvertebrates. The aim of this work is to study the effects of the characteristics of streambed substrate, such as grain size, shape, and roughness, on the composition and biodiversity of macroinvertebrates. A field experiment was done on the Juma River, a second-order mountain stream in northern China. Substrata of cobbles, hewn stones, pebbles, coarse sand, and fine sand were used to replace the original gravel and sand bed in a stretch of 30 m in length. The sampling results indicated that the macroinvertebrate assemblage is significantly affected by the grain size, porosity and interstitial dimension of the substrate, while it is rarely affected by the shape and the surface roughness of the experimental substrata. Macroinvertebrate compositions in cobbles and hewn stones were stable and changed least over time. The taxa richness and density of individuals in the substrata of cobbles, hewn stones, and pebbles are much higher than in those of the coarse sand and fine sand.

关键词: Substrata     physical environmental     indicator     ecology     substrate    

Aerobic granular sludge formation based on substrate availability: Effects of flow pattern and fermentation

Quan Yuan, Hui Gong, Hao Xi, Kaijun Wang

《环境科学与工程前沿(英文)》 2020年 第14卷 第3期 doi: 10.1007/s11783-020-1226-0

摘要: Penetration depth and substrate characters affect AGS formation and performance. The relationship between substrate gradient and particle size affects AGS stability. The fermentation process is proposed as a pretreatment to improve AGS stability. The influences of flow patterns (mixed-flow and plug-flow) and fermentation pretreatment on aerobic granular sludge (AGS) formation with various substrate availability levels were investigated by running four identical laboratory-scale sequencing batch reactors (R1–R4), comparing two anaerobic feeding strategies and three kinds of substrates. R1 achieved faster granulation with a fast influent fill step followed by a modified anaerobic mixed-flow phase, but the AGS showed poorer stability with a cracked structure and a high suspended solids concentration in the effluent. The anaerobic plug-flow feeding mode (with influent fed slowly from the bottom) in R2 provided deeper penetration depth for the substance to reach the core of AGS and accordingly strengthen AGS stability. An acidogenic up-flow sludge bed reactor was introduced as a pretreatment to improve the AGS performance by enhancing glucose pre-fermentation (R4). AGS fed with mixed volatile fatty acids (VFA) after glucose fermentation showed similar performance compared with the reactor fed with acetate in the aspects of stability, structure, size distribution and nitrogen removal efficiency, and 74% similarity in the microbial community. For actual wastewater with low VFA concentrations, fermentation treatment was suggested as a promising pretreatment for stable AGS granulation and operation.

关键词: Anaerobic plug-flow feeding mode     Anaerobic mixed-flow mode     Fermentation pretreatment     Substrate gradient     Penetration depth    

V-shaped substrate for surface and volume enhanced Raman spectroscopic analysis of microplastics

《环境科学与工程前沿(英文)》 2022年 第16卷 第11期 doi: 10.1007/s11783-022-1578-8

摘要:

● V-shaped substrate was obtained for SERS analysis of microplastics (diameter ≈ 1 μm).

关键词: SERS     V-shaped     AAO     Microplastic     Atmospheric aerosol    

Elastic modulus and thermal stress in coating during heat cycling with different substrate shapes

Daniel GAONA,Alfredo VALAREZO

《机械工程前沿(英文)》 2015年 第10卷 第3期   页码 294-300 doi: 10.1007/s11465-015-0351-0

摘要:

The elastic modulus of a deposit (Ed) can be obtained by monitoring the temperature (?T) and curvature (?k) of a one-side coated long plate, namely, a one-dimensional (1D) deformation model. The aim of this research is to design an experimental setup that proves whether a 1D deformation model can be scaled for complex geometries. The setup includes a laser displacement sensor mounted on a robotic arm capable of scanning a specimen surface and measuring its deformation. The reproducibility of the results is verified by comparing the present results with Stony Brook University Laboratory’s results. The ?k-?T slope error is less than 8%, and the Ed estimation error is close to 2%. These values reveal the repeatability of the experiments. Several samples fabricated with aluminum as the substrate and 100MXC nanowire (Fe and Cr alloy) as the deposit are analyzed and compared with those in finite element (FE) simulations. The linear elastic behavior of 1D (flat long plate) and 2D (squared plate) specimens during heating/cooling cycles is demonstrated by the high linearity of all ?k-?T curves (over 97%). The Ed values are approximately equal for 1D and 2D analyses, with a median of 96 GPa and standard deviation of 2 GPa. The correspondence between the experimental and simulated results for the 1D and 2D specimens reveals that deformation and thermal stress in coated specimens can be predicted regardless of specimen geometry through FE modeling and by using the experimental value of Ed. An example of a turbine-blade-shaped substrate is presented to validate the approach.

关键词: in-plane     Young’s modulus     curvature temperature     thermal stress     coating    

Crk-associated substrate, vascular smooth muscle and hypertension

TANG Dale

《医学前沿(英文)》 2008年 第2卷 第4期   页码 323-331 doi: 10.1007/s11684-008-0062-6

摘要: Hypertension is characterized by vascular smooth muscle constriction and vascular remodeling involving cell migration, hypertrophy and growth. Crk-associated substrate (CAS), the first discovered member of the adapter protein CAS family, has been shown to be a critical cellular component that regulates various smooth muscle functions. In this review, the molecular structure and protein interactions of the CAS family members are summarized. Evidence for the role of CAS in the regulation of vascular smooth muscle contractility is presented. Contraction stimulation induces CAS phosphorylation on Tyr-410 in arterial smooth muscle, creating the binding site for the Src homology (SH) 2/SH3 protein CrkII, which activates neuronal Wiskott-Aldrich syndrome protein (N-WASP)-mediated actin assembly and force development. The functions of CAS in cell migration, hypertrophy and growth are also summarized. Abelson tyrosine kinase (Abl), c-Src, focal adhesion kinase (FAK), proline-rich tyrosine kinase 2 (PYK2), protein tyrosine phosphatase-proline, glutamate, serine and threonine sequence protein (PTP-PEST) and SHP-2 have been documented to coordinate the phosphorylation and dephosphorylation of CAS. The downstream signaling partners of CAS in the context of cell motility, hypertrophy, survival and growth are also discussed. These new findings establish the important role of CAS in the modulation of vascular smooth muscle functions. Furthermore, the upstream regulators of CAS may be new biologic targets for the development of more effective and specific treatment of cardiovascular diseases such as hypertension.

关键词: Contraction stimulation     phosphatase-proline     molecular structure     discovered     hypertension    

Recent advances in SERS detection of perchlorate

Jumin Hao, Xiaoguang Meng

《化学科学与工程前沿(英文)》 2017年 第11卷 第3期   页码 448-464 doi: 10.1007/s11705-017-1611-9

摘要: Perchlorate has recently emerged as a widespread environmental contaminant of healthy concern. Development of novel detection methods for perchlorate with the potential for field use has been an urgent need. The investigation has shown that surface-enhanced Raman scattering (SERS) technique has great potential to become a practical analysis tool for the rapid screening and routine monitoring of perchlorate in the field, particularly when coupled with portable/handheld Raman spectrometers. In this review article, we summarize progress made in SERS analysis of perchlorate in water and other media with an emphasis on the development of SERS substrates for perchlorate detection. The potential of this technique for fast screening and field testing of perchlorate-contaminated environmental samples is discussed. The challenges and possible solutions are also addressed, aiming to provide a better understanding on the development directions in the research field.

关键词: perchlorate     SERS     detection     substrate     modification     nanostructure    

Laser sintering of Cu nanoparticles on PET polymer substrate for printed electronics at different wavelengths

Juan Carlos HERNANDEZ-CASTANEDA, Boon Keng LOK, Hongyu ZHENG

《机械工程前沿(英文)》 2020年 第15卷 第2期   页码 303-318 doi: 10.1007/s11465-019-0562-x

摘要: This study explores the feasibility of different laser systems to sinter screen-printed lines from nonconductive copper nanoparticles (Cu NPs) on polyethylene terephthalate polymer film. These materials are commonly used in manufacturing functional printed electronics for large-area applications. Here, optical and thermal characterization of the materials is conducted to identify suitable laser sources and process conditions. Direct diode (808 nm), Nd:YAG (1064 nm and second harmonic of 532 nm), and ytterbium fiber (1070 nm) lasers are explored. Optimal parameters for sintering the Cu NPs are identified for each laser system, which targets low resistivity and high processing speed. Finally, the quality of the sintered tracks is quantified, and the laser sintering mechanisms observed under different wavelengths are analyzed. Practical considerations are discussed to improve the laser sintering process of Cu NPs.

关键词: laser sintering     copper nanoparticles     printed electronics    

Dewatering of Scenedesmus Obliquus Cultivation Substrate with Microfiltration: Potential and Challenges

Marco Malaguti,Lorenzo Craveri,Francesco Ricceri,Vincenzo Riggio,Mariachiara Zanetti,Alberto Tiraferri,

《工程(英文)》 doi: 10.1016/j.eng.2023.07.010

摘要: In the microalgae harvesting process, which includes a step for dewatering the algal suspension, directly reusing extracted water in situ would decrease the freshwater footprint of cultivation systems. Among various algae harvesting techniques, membrane-based filtration has shown numerous advantages. This study evaluated the reuse of permeate streams derived from Scenedesmus obliquus (S. obliquus) biomass filtration under bench-scale and pilot-scale conditions. In particular, this study identified a series of challenges and mechanisms that influence the water reuse potential and the robustness of the membrane harvesting system. In a preliminary phase of this investigation, the health status of the initial biomass was found to have important implications for the harvesting performance and quality of the permeate stream to be reused; healthy biomass ensured better dewatering performance (i.e., higher water fluxes) and higher quality of the permeate water streams. A series of bench-scale filtration experiments with different combinations of cross-flow velocity and pressure values were performed to identify the operative conditions that would minimize energy requirements while maximizing water productivity. The optimal conditions, 2.2 m·s−1 and 1.4 bar (1 bar = 105 Pa), respectively, were then applied to drive pilot-scale microfiltration tests to reuse the collected permeate as a new cultivation medium for S. obliquus growth in a pilot-scale photo-bioreactor. The investigation revealed key differences between the behavior of the membrane systems at the two scales (bench and pilot). It indicated the potential for beneficial reuse of the permeate stream as the pilot-scale experiments ensured high harvesting performance and growth rates of biomass in permeate water that were highly similar to those recorded in the ideal cultivation medium. Finally, different nutrient reintegration protocols were investigated, revealing that both macro- and micronutrient levels are critical for the success of the reuse approach.

关键词: Scenedesmus obliquus     Microfiltration     Permeate reuse     Harvesting     Microalgae     Pilot-scale    

Microalgae

Sanath KONDAVEETI,Kwang Soon CHOI,Ramesh KAKARLA,Booki MIN

《环境科学与工程前沿(英文)》 2014年 第8卷 第5期   页码 784-791 doi: 10.1007/s11783-013-0590-4

摘要: Renewable algae biomass, was used as substrate for generating electricity in two chamber microbial fuel cells (MFCs). From polarization test, maximum power density with pretreated algal biomass was 102 mW·m (951 mW·m ) at current generation of 276 mA·m . The individual electrode potential as a function of current generation suggested that anodic oxidation process of algae substrate had limitation for high current generation in MFC. Total chemical oxygen demand (TCOD) reduction of 74% was obtained when initial TCOD concentration was 534 mg·L for 150 h of operation. The main organic compounds of algae oriented biomass were lactate and acetate, which were mainly used for electricity generation. Other by-products such as propionate and butyrate were formed at a negligible amount. Electrochemical Impedance Spectroscopy (EIS) analysis pinpointed the charge transfer resistance (112 ?) of anode electrode, and the exchange current density of anode electrode was 1214 nA·cm .

关键词: microbial fuel cell (MFC)     algae     bioelectricity     substrate     volatile fatty acid     biomass     COD removal efficiency    

Preparation of D-lysine by chemical reaction and microbial asymmetric transformation

LIU Yi, JIAO Qingcai, YIN Xiaoxing

《化学科学与工程前沿(英文)》 2008年 第2卷 第1期   页码 40-43 doi: 10.1007/s11705-008-0023-2

摘要: The DL-lysine crystals from the racemization of L-lysine was treated as substrate with AS1.1009 intact cells as biocatalysts to produce crystalline D-lysine with a yield of 56.6% from the reaction mixture after simple purification. In the presence of 0.10 molar equivalent of salicylaldehyde, L-lysine racemization can be completed within 4 h in 1.0 mol/L of NaOH at 100°C. The activation energy of the processes was 62187.86 J/mol. The characteristics of AS1.1009 decarboxylase were studied. Under the conditions of pH 8.0, temperature 37°C, cell concentration 10 g/L, tween-80 0.5 g/L, substrate concentration 30 g/L, and the specific activity of up to 3840 U, L-lysine can be completely degraded by the decarboxylase for 12 h under the optimal conditions.

关键词: substrate     temperature     specific activity     presence     decarboxylase    

and nitrate removal from secondary effluent in constructed wetlands using a new manganese-containing substrate

《环境科学与工程前沿(英文)》 2023年 第18卷 第4期 doi: 10.1007/s11783-024-1807-4

摘要:

● MnO2/PCL composite material (MPCM) enhances ammonia and nitrate removal in CWs.

关键词: Constructed wetland     Nitrogen removal     Manganese redox     Polycaprolactone     Nitrous oxide    

Thin-film composite forward osmosis membranes with substrate layer composed of polysulfone blended with

Baicang Liu,Chen Chen,Pingju Zhao,Tong Li,Caihong Liu,Qingyuan Wang,Yongsheng Chen,John Crittenden

《化学科学与工程前沿(英文)》 2016年 第10卷 第4期   页码 562-574 doi: 10.1007/s11705-016-1588-9

摘要: To advance commercial application of forward osmosis (FO), we investigated the effects of two additives on the performance of polysulfone (PSf) based FO membranes: one is poly(ethylene glycol) (PEG), and another is PSf grafted with PEG methyl ether methacrylate (PSf-g-PEGMA). PSf blended with PEG or PSf-g-PEGMA was used to form a substrate layer, and then polyamide was formed on a support layer by interfacial polymerization. In this study, NaCl (1 mol?L ) and deionized water were used as the draw solution and the feed solution, respectively. With the increase of PEG content from 0 to 15 wt-%, FO water flux declined by 23.4% to 59.3% compared to a PSf TFC FO membrane. With the increase of PSf-g-PEGMA from 0 to 15 wt-%, the membrane flux showed almost no change at first and then declined by about 52.0% and 50.4%. The PSf with 5 wt-% PSf-g-PEGMA FO membrane showed a higher pure water flux of 8.74 L?m ?h than the commercial HTI membranes (6–8 L?m ?h ) under the FO mode. Our study suggests that hydrophobic interface is very important for the formation of polyamide, and a small amount of PSf-g-PEGMA can maintain a good condition for the formation of polyamide and reduce internal concentration polarization.

关键词: thin-film composite     forward osmosis     amphiphilic copolymer     interfacial polymerization     poly(ethylene glycol)    

β-Cyclodextrin promoted oxidation of primary amines to nitriles in water

Dongpo SHI, Hongbing JI, Zhong LI

《化学科学与工程前沿(英文)》 2009年 第3卷 第2期   页码 196-200 doi: 10.1007/s11705-009-0051-6

摘要: A facile, efficient and substrate-selective oxidation of the primary amines with NaClO as oxidant catalyzed by cyclodextrin ( CD) has been developed in water for the first time, and the behavior of cyclodextrin that catalyzed the primary amines to nitriles in water was investigated. It was found that the primary amines which could form host-guest complexes with cyclodextrin were oxidized to nitriles with excellent yields at ambient temperature. The results show that cyclodextrin worked not only as a solubilizing agent but also as a catalyst in these reactions.

关键词: substrate-selective     amines oxidation     β-cyclodextrin    

Performance analysis of piezoelectric bimorph generator

KAN Junwu, TANG Kehong, ZHAO Hongwei, SHAO Chenghui, ZHU Guoren

《机械工程前沿(英文)》 2008年 第3卷 第2期   页码 151-157 doi: 10.1007/s11465-008-0039-9

摘要: In this paper, the theoretical model and simulation of the performance of a piezoelectric (PZT) bimorph generator is introduced. The generator consists of two piezoelectric plates bonded on a substrate metal plate. For an effective electromechanical coupling coefficient (EECC) and the generated energy, the analytical formulae are established with the thickness ratio and the Young’s modulus ratio as variables. After giving correlative material parameters, the EECC and generated energy can be computed. The results show that there is a optimal thickness ratio for a piezoelectric bimorph generator to achieve the maximum EECC and electrical energy. The EECC and generated energy decrease with an increase of the Young’s modulus ratio. In addition, the influence of mechanical source on electrical energy generation and power output is also considered.

关键词: piezoelectric bimorph     substrate     addition     PZT     mechanical    

Preparation and characterization of EVAL hollow fiber membrane adsorbents filled with cation exchange resins

Fengli ZHANG, Yuzhong ZHANG, Hong LI, Guangfen LI,

《化学科学与工程前沿(英文)》 2009年 第3卷 第4期   页码 462-467 doi: 10.1007/s11705-009-0011-1

摘要: EVAL hollow fiber membrane adsorbents filled with powder D061-type cation exchange resin were prepared through dry-wet spinning process, using hydrophilic copolymer EVAL as the fiber substrate. The microstructures of the membrane adsorbents were observed, and the pure water fluxes, BSA rejection, and static adsorption capacities of membrane adsorbents for BSA were measured. The effect of the resin-filled content on membrane performance has been discussed. The results showed that EVAL hollow fiber membrane adsorbents filled with D061-type cation exchange resins had good adsorption capacity, and the adsorption capacity increased with the quantity of the resin-filled content. The static protein adsorption capacity was 77.14 mg BSA/g membrane adsorbents when D061 resin loading content was 65% at pH 4.5.

关键词: substrate     copolymer EVAL     exchange     EVAL hollow     resin-filled content    

标题 作者 时间 类型 操作

Effect of streambed substrate on macroinvertebrate biodiversity

DUAN Xuehua, WANG Zhaoyin, TIAN Shimin

期刊论文

Aerobic granular sludge formation based on substrate availability: Effects of flow pattern and fermentation

Quan Yuan, Hui Gong, Hao Xi, Kaijun Wang

期刊论文

V-shaped substrate for surface and volume enhanced Raman spectroscopic analysis of microplastics

期刊论文

Elastic modulus and thermal stress in coating during heat cycling with different substrate shapes

Daniel GAONA,Alfredo VALAREZO

期刊论文

Crk-associated substrate, vascular smooth muscle and hypertension

TANG Dale

期刊论文

Recent advances in SERS detection of perchlorate

Jumin Hao, Xiaoguang Meng

期刊论文

Laser sintering of Cu nanoparticles on PET polymer substrate for printed electronics at different wavelengths

Juan Carlos HERNANDEZ-CASTANEDA, Boon Keng LOK, Hongyu ZHENG

期刊论文

Dewatering of Scenedesmus Obliquus Cultivation Substrate with Microfiltration: Potential and Challenges

Marco Malaguti,Lorenzo Craveri,Francesco Ricceri,Vincenzo Riggio,Mariachiara Zanetti,Alberto Tiraferri,

期刊论文

Microalgae

Sanath KONDAVEETI,Kwang Soon CHOI,Ramesh KAKARLA,Booki MIN

期刊论文

Preparation of D-lysine by chemical reaction and microbial asymmetric transformation

LIU Yi, JIAO Qingcai, YIN Xiaoxing

期刊论文

and nitrate removal from secondary effluent in constructed wetlands using a new manganese-containing substrate

期刊论文

Thin-film composite forward osmosis membranes with substrate layer composed of polysulfone blended with

Baicang Liu,Chen Chen,Pingju Zhao,Tong Li,Caihong Liu,Qingyuan Wang,Yongsheng Chen,John Crittenden

期刊论文

β-Cyclodextrin promoted oxidation of primary amines to nitriles in water

Dongpo SHI, Hongbing JI, Zhong LI

期刊论文

Performance analysis of piezoelectric bimorph generator

KAN Junwu, TANG Kehong, ZHAO Hongwei, SHAO Chenghui, ZHU Guoren

期刊论文

Preparation and characterization of EVAL hollow fiber membrane adsorbents filled with cation exchange resins

Fengli ZHANG, Yuzhong ZHANG, Hong LI, Guangfen LI,

期刊论文